Power tool architecture with handle-received battery systems

Abstract

A power tool includes a housing having a motor housing supporting an electric motor and a handle assembly extending from the motor housing. A removable battery pack is configured to mount into the handle assembly and has a geometry complementary thereto. The handle assembly provides a first partial grip surface, and the battery pack provides a second partial grip surface such that, when mounted, the handle assembly and the battery pack together form a grip surface for user engagement. The battery pack includes a first housing portion and a second housing portion arranged along a common axis, with at least one first battery cell housed within the first housing portion and a plurality of second battery cells housed within the second housing portion. The first housing portion is received at least partially within the handle assembly, and the second housing portion remains external.

Description

P-WO-TN-2025-0009 / / 1076-0022WO Patent POWER TOOL ARCHITECTURE WITH HANDLE-RECEIVED BATTERY SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 750,185, filed January 27, 2025, entitled POWER TOOL AND BATTERY PACK INCLUDING A GRIP SURFACE, the disclosure of which is hereby incorporated herein by reference in its entirety for all purposes.FIELD

[0002] This disclosure generally relates to power tools and, more particularly, to power tool architectures involving batteries receivable by a handle assembly of a tool and electrical and mechanical interfaces between battery, control electronics, and drive components.BACKGROUND

[0003] Power tools may be provided in different configurations depending on the type of output or operation performed by the power tool, such as drilling, fastening, cutting, or grinding. Some power tools may be powered by a direct current (DC) power source, such as a removable battery pack, that supplies electrical power to a motor and associated control electronics. Such batteries may be receivable by or coupled to a tool housing in various locations and orientations. Electrical coupling between the battery, control electronics, and motor may involve conductors routed within internal cavities of the housing, and the arrangement of these components can influence assembly processes, internal packaging, handle geometry7, and overall tool configuration. Tool housings may be formed from multiple cooperating housing portions that support and enclose electrical and mechanical assemblies, and power tools may be produced in multiple configurations differing in motor characteristics, operating modes, or output assemblies.SUMMARY

[0004] According to an embodiment, a power tool is provided including a housing including a motor housing that supports an electric motor and a handle portion extending from the motor housing, wherein the handle portion provides a partial grip surface; and a battery pack configured to mount into the handle portion, the battery pack having a complementary geometry to the handle portion, wherein the battery pack and the handle portion together form a grip surface for user engagement.

[0005] In an embodiment, the battery pack includes a first housing portion, a second housing portion orientated coaxially with the first housing portion and having a greater circumference than the first housing portion, at least one first battery cell housed within the first housing portion, and a plurality of second battery7cells housed within the second housing portion.

[0006] In an embodiment, the first housing portion is received at least partially into the handle portion of the power tool, and the second housing portion includes complementary geometry7to form the grip surface together with the handle portion.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0007] In an embodiment, the handle portion of the power tool forms a first partial handle portion and the battery pack forms a second partial handle portion that complements the first partial handle to form a grip handle for the power tool when the battery pack is mounted into the handle portion.

[0008] In an embodiment, the second housing portion fully capture the plurality of second battery cells and overlaps a portion of the at least one first battery cell.

[0009] In an embodiment, the battery7pack includes a cell holder including a first cell holder portion configured to hold the at least one first battery7cell along a center axis of the first housing portion, and a second cell holder portion configured to hold the plurality7of second battery cells along a center axis of the second housing portion. In an embodiment, the first housing portion is coaxial with the second housing portion.

[0010] In an embodiment, an adaptor is provided configured to be mountable into the handle portion and including a foot portion forming a battery receptacle for receiving a sliding battery pack.

[0011] Additional features and advantages of various embodiments will be set forth, in part, in the description that follows, and will, in part, be apparent from the description, or may be learned by the practice of various embodiments. The objectives and other advantages of various embodiments w ill be realized and attained by means of the elements and combinations particularly pointed out in the description herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Throughout the drawings, reference numbers can be re-used to indicate correspondence betw een referenced elements. The draw ings are provided to illustrate embodiments of the present disclosure and do not limit the scope thereof.

[0013] FIG. 1 illustrates a perspective view of a powder tool in accordance with the disclosure in an assembled configuration w ith a battery7pack coupled thereto.

[0014] FIG. 2 illustrates a perspective view of the power tool of FIG. 1 with the battery pack separated from the handle assembly and positioned for insertion along a battery insertion axis into the handle assembly.

[0015] FIG. 3 illustrates an exploded perspective view of the power tool of FIG. 1 with the battery pack removed, showing separation between the power train assembly and the handle assembly along a power train assembly attachment axis.

[0016] FIG. 4 illustrates a cross-sectional view of the power tool of FIG. 1 with no battery¬ pack installed.

[0017] FIGS. 5A, 5B, 5C, 5D, 5E, and 5F illustrate the power tool of FIG. 1 showing orthogonal views of the power tool with a first example battery pack coupled thereto.

[0018] FIGS. 6A, 6B, 6C, 6D, 6E, and 6F illustrate left-side elevation, front elevation, rightside elevation, rear elevation, top elevation, and bottom elevation views, respectively, of the battery pack of FIGS. 5A-5F.

[0019] FIGS. 7A and 7B illustrate partially exploded views of the battery pack of FIGS. 6A-6F.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0020] FIGS. 8A and 8B illustrate partially exploded isometric views of the battery pack of FIGS. 6A-6F with portions of the pack housing removed for clarity.

[0021] FIGS. 9 A and 9B illustrate perspective views of a lower-end electronics subassembly of the battery pack of FIGS. 6A-6F.

[0022] FIGS. 10A, 10B, IOC, 10D. 10E, and 10F illustrate various views of abattery assembly of the battery pack of FIGS. 6A-6F.

[0023] FIG. 11 illustrates an isolated view of electrical interconnection members of the battery' pack of FIGS. 6A-6F, without battery cells or internal support structures.

[0024] FIGS. 12A and 12B illustrate isolated views of battery cells and electrical interconnection members of the battery' pack of FIGS. 6A-6F, with housing and support structures omitted.

[0025] FIGS. 13A and 13B illustrate views of an internal support and electrical interconnection structure of the battery assembly of the battery pack of FIGS. 6A-6F.

[0026] FIGS. 14A and 14B illustrate views showing representative placement of battery pack terminals of the battery pack of FIGS. 6A-6F, relative to adjacent battery cells.

[0027] FIGS. 15A. 15B. 15C, and 15D illustrate schematic views of the battery assembly of the battery pack of FIGS. 6A-6F, taken from different viewing orientations.

[0028] FIG. 16 illustrates a schematic elevation view of the battery assembly of the battery pack of FIGS. 6A-6F, showing representative axis relationships.

[0029] FIGS. 17A and 17B illustrate respective views of the power tool of FIG. 1 with a battery' pack installed, with pack housing omitted to show relative battery-cell positioning.

[0030] FIGS. 18A, 18B, 18C, 18D, 18E, and 18F illustrate the power tool of FIG. 1 shoyving orthogonal views yvith a second example battery' pack coupled thereto.

[0031] FIG. 18G illustrates the poyver tool in accordance yvith the disclosure, shoyvn in a representative operating configuration yvith a user’s hand positioned on a handle assembly.

[0032] FIGS. 18H and 181 illustrate a trigger-integrated battery retention interlock member operatively coupled to a trigger assembly.

[0033] FIG. 18J illustrates a top view of the power tool of FIG. 18G showing a receiving space positioned within the housing and aligned with the battery receptacle.

[0034] FIGS. 19A, 19B, 19C, 19D, 19E, and 19F illustrate left-side elevation, front elevation, right-side elevation, rear elevation, top elevation, and bottom elevation views, respectively, of the battery pack of FIGS. 18A-18F.

[0035] FIGS. 20A and 20B illustrate exploded isometric vieyvs of the battery pack of FIGS.18 A- 18F. with internal components separated from a pack housing.

[0036] FIGS. 21A, 21B, 21C, 21D, 21E, 21F, 21G, and 21H illustrate various views of an internal battery assembly of the battery' pack of FIGS. 18A-18F.

[0037] FIG. 22 illustrates an isometric view of an internal support and electrical interconnection structure of the battery' pack of FIGS. 18A-18F, yvith battery' cells omitted.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0038] FIGS. 23A, 23B, 23C. 23D, 23E, and 23F illustrate schematic views of the internal battery assembly of the battery pack of FIGS. 18A-18F. showing representative spatial relationships among battery cells.

[0039] FIG. 24 illustrates an isometric cross-sectional view of the battery pack of FIGS. 18A-18F, showing an internal battery assembly positioned within a pack housing.

[0040] FIGS. 25 A and 25B illustrate views of the power tool of FIG. 1 with the battery pack of FIGS. 18A-18F received by ahandle assembly, with portions shown in outline or section.

[0041] FIG. 25C is a schematic representation of volumetric regions of the battery pack and is not draw n to scale.

[0042] FIG. 25D illustrates a schematic representation of a handle-associated volumetric region of the battery pack when installed in a pow er tool.

[0043] FIG. 26A illustrates a perspective view of a first embodiment of an adapter in accordance with the disclosure, shown separate from a power tool and separate from a battery pack.

[0044] FIG. 26B illustrates an exploded view of the power tool of FIG. 1 with the adapter of FIG. 26A and a battery pack shown separated from one another and from a handle assembly of the power tool.

[0045] FIG. 26C illustrates the power tool of FIG. 1 ith the adapter of FIG. 26A installed in a battery receptacle cavity of the handle assembly and with the battery pack separated from the adapter.

[0046] FIG. 26D illustrates the power tool of FIG. 1 with the adapter of FIG. 26A installed in the handle assembly and the battery7pack coupled to the adapter.

[0047] FIG. 27A illustrates a perspective view7of a second embodiment of an adapter in accordance with the disclosure, shown separate from a power tool and separate from a battery7pack.

[0048] FIG. 27B illustrates an exploded view of the power tool of FIG. 1 with the adapter of FIG. 27A and a battery pack shown separated from one another and from ahandle assembly of the power tool.

[0049] FIG. 27C illustrates the power tool of FIG. 1 with the adapter of FIG. 27A installed in a battery receptacle cavity of the handle assembly and with the battery pack separated from the adapter.

[0050] FIG. 27D illustrates the power tool of FIG. 1 with the adapter of FIG. 27A installed in the handle assembly and the battery pack coupled to the adapter.

[0051] FIG. 28 A illustrates an exploded view of the power tool of FIG. 1 in a partially exploded configuration.

[0052] FIGS. 28B and 28C illustrate additional exploded views of a power train assembly shown in FIG. 28A, from different perspectives.

[0053] FIG. 28D illustrates an assembled view of the power train assembly show n in FIG.28A, separated from the handle assembly.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0054] FIG. 28E illustrates the power train assembly shown in FIG. 28A, positioned on the handle assembly along a tool-head attachment axis, with securing members shown separated from the handle assembly.

[0055] FIG. 28F illustrates the power tool of FIG. 28A in a fully assembled configuration with the power train assembly secured to the handle assembly by the securing members.

[0056] FIGS. 29A and 29B illustrate exploded comparison views of a plurality of power tools configured in accordance with the modular platform architecture, shown from different perspectives.

[0057] FIGS. 30A and 30B illustrate assembled comparison side views of a plurality of power tools configured in accordance with the modular platform architecture.

[0058] FIG. 30C illustrates a separated view of a rear end cap relative to a motor housing portion.

[0059] FIG. 31 illustrates exploded comparison side views of a plurality of power tools configured in accordance with the modular platform architecture, with respective power train assemblies shown separated from a common handle assembly.

[0060] FIGS. 32A and 32B illustrate the handle assembly of the power tool of FIG. 1 shown isolated from other components, with FIG. 32A illustrating an assembled perspective view and FIG. 32B illustrating an exploded perspective view showing internal components including a trigger and control subassembly.

[0061] FIGS. 33A and 33B illustrate exploded perspective views of the trigger and control subassembly of FIG. 32B, shown separated into individual components.

[0062] FIG. 34 illustrates a perspective cross-sectional assembled view of the trigger and control subassembly of the power tool of FIG. 1 , illustrating an example contactless sensing architecture.

[0063] FIGS. 35A and 35B illustrate cross-sectional side views of a portion of the trigger and control subassembly disposed within the handle assembly, showing relative positional relationships in different trigger operating conditions.

[0064] FIG. 36A illustrates a perspective view of a portion of the trigger and control subassembly, showing components associated with a direction control function.

[0065] FIGS. 36B and 36C illustrate front elevational views of a portion of the trigger and control subassembly, showing an example mechanical lockout interaction between a direction control actuator and a trigger.

[0066] FIGS. 37A, 37B, and 37C illustrate perspective views of a portion of the trigger and control subassembly, showing a direction control actuator and an associated actuation element in different discrete positional conditions.

[0067] FIG. 38 illustrates an exploded perspective view of a portion of the trigger and control subassembly, showing relative positioning of a PCB, a sensor element, and multiple actuation elements associated with trigger and direction control.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0068] FIG. 39 illustrates a perspective cross-sectional assembled view of a portion of a trigger and control subassembly, illustrating an example sealed electronics module formed by cooperation between trigger assembly structure and a compliant sealing arrangement.

[0069] FIGS. 40A and 40B illustrate a standalone magnetic field sensing switch assembly- configured as a self-contained user-input module.

[0070] FIG. 41 A illustrates a partially exploded schematic view of a portion of a power tool in accordance with the present disclosure.

[0071] FIGS. 42 A and 42B illustrate perspective views of a motor interconnect structure configured for mounting at or adjacent an axial end of an electric motor.

[0072] FIGS. 43 A and 43B illustrate views of a motor assembly including an electric motor and a motor interconnect mounted at an axial end region of the electric motor.

[0073] FIG. 44A illustrates a perspective view of a portion of a power tool in which a motor assembly is electrically and mechanically coupled to a trigger and control subassembly.

[0074] FIG. 44B illustrates a side cross-sectional view- of the power tool showing a motor assembly mounted to a handle assembly.

[0075] FIG. 45 illustrates a schematic perspective view of a connectorized peripheral interface architecture implemented using a common electronics assembly in accordance with the present disclosure.

[0076] FIG. 46A illustrates a partially exploded perspective view of a trigger and control subassembly of a power tool in accordance with the present disclosure.

[0077] FIG. 46B illustrates a perspective view- of a trigger and control subassembly in a partially assembled condition with portions of a surrounding handle assembly omitted for clarity.

[0078] FIG. 46C illustrates a cross-sectional view of a trigger and control subassembly taken along a sectional plane.

[0079] FIG. 46D illustrates a cross-sectional view of a trigger and control subassembly taken along a sectional plane.

[0080] FIG. 46E illustrates a partially exploded top perspective view of a terminal block and adjacent components of a trigger and control subassembly.

[0081] FIG. 46F illustrates a partially exploded perspective view' of a trigger and control subassembly showing a trigger cavity defined within a handle assembly and portions of a trigger assembly positioned for installation into the trigger cavity.

[0082] FIGS. 47 A, 47B, 47C, and 47D illustrate various views of portions of a handle assembly showing cooperative structural relationships that together define a battery receptacle cavity.

[0083] FIG. 48A illustrates a rear perspective view of a power tool having a motor housing end cap disposed at a rearw ard end of the motor housing.

[0084] FIG. 48B illustrates a partial cross-sectional view' of a power tool showing internal relationships between a printed circuit board user interface components and structural features of a motor housing end cap.P-WO-TN-2025-0009 / / 1076-0022WO Patent

[0085] FIGS. 49A and 49B illustrate cross-sectional side views of a power tool in accordance with the disclosure having a pistol-grip configuration.

[0086] FIGS. 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H illustrate a power tool in accordance with the disclosure, show ing orthogonal and perspective views of the power tool with the battery pack of FIGS. 18A-18F coupled thereto.

[0087] FIG. 51 illustrates a perspective view of the power tool of FIGS. 50A-50H with the battery pack separated from the handle assembly.

[0088] FIG. 52 illustrates a sectional side view of the power tool of FIGS. 50A-50H with the battery pack installed in the handle assembly, taken along a longitudinal plane extending generally along an inline axis of the tool.

[0089] FIGS. 53A and 53B illustrate sectional views taken through a rear motor-interface region of the power tool of FIGS. 50A-50H, showing internal mechanical and electrical components.

[0090] FIG. 53C illustrates a longitudinal sectional view of the power tool of FIGS. 50A-50H with the battery pack removed, showing internal electrical components and battery-interface features.

[0091] FIG. 54A illustrates a side elevation view of the power tool of FIGS. 50A-50H with the battery pack removed.

[0092] FIG. 54B illustrates a rear elevation view of the power tool of FIGS. 50A-50H with the battery pack removed.

[0093] FIG. 55 illustrates an exploded perspective view of the power tool of FIGS. 50A-50H showing a guard assembly separated from a forward portion of the tool.

[0094] FIGS. 56A and 56B illustrate exploded perspective views of the power tool of FIGS.50A-50H showing separation of a removable output module from a forward portion of the housing assembly.

[0095] FIG. 57 illustrates a perspective view of the power tool of FIGS. 50A-50H with a removable locking element separated from a forward portion of the housing assembly.

[0096] FIGS. 58A and 58B illustrate exploded perspective views showing an interface between a housing assembly and a gear case of the power tool of FIGS. 50A-50H.

[0097] FIG. 59 illustrates an exploded perspective view of the power tool of FIGS. 50A-50H showing housing portions, a motor assembly, and a gear case.

[0098] FIGS. 60A. 60B. 60C. 60D. 60E, and 60F illustrate multiple views of a motor and housing arrangement of the power tool of FIGS. 50A-50H.

[0099] FIG. 61 illustrates a view of a motor assembly of the power tool of FIGS. 50A-50H with portions of the housing removed.[000100] FIGS. 62A and 62B illustrate views of a first motor housing portion of the power tool of FIGS. 50A-50H.[000101] FIG. 63 illustrates a second motor housing portion and a handle housing portion of the power tool of FIGS. 50A-50H.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000102] FIGS. 64A and 64B illustrate perspective views of a portion of a power tool in accordance with some aspect of the present disclosure.[000103] FIG. 64C. 64D. and 64E illustrate front, side, and rear views of the power tool of FIG.64A.[000104] FIGS. 65 A, 65B, and 65C and illustrate partially exploded schematic views of a portion of the power tool of FIG. 64 A.[000105] FIGS. 66A, 66B, and 66C illustrate various exploded views of portions of the power tool of FIG. 64A, showing cooperative structural relationships between a front-loading subassembly and a single-piece molded housing.[000106] FIG. 66B illustrates the front-loading subassembly aligned with the housing along the front-loading insertion direction.[000107] FIG. 66C illustrates side views of the front-loading subassembly and the housing, further demonstrating the multi-plane relationship between the side wall portion and the upper wall portion.[000108] FIG. 67 illustrates a partially exploded perspective view of a portion of a front-loading subassembly.[000109] FIG. 68A illustrates a perspective view of a portion of a front-loading subassembly of the power tool, showing structural features that can cooperate to define a potting boat for receiving a sealed electronics module.[000110] FIG. 68B illustrates a perspective cross-sectional assembled view of a portion of a front-loading subassembly installed within a power tool, showing an example trigger and sealed-electronics interface architecture.[000111] FIG. 69 depicts a perspective view of a power tool in accordance with the disclosure having a handle portion extending transversally from a motor housing and a batteiy pack mounted to the handle portion.[000112] FIG. 70 depicts a perspective view of the battery pack of FIG. 69 detached from the power tool.[000113] FIG. 71 depicts a side view of the power tool and the batteiy’ pack of FIG. 69.[000114] FIG. 72 depicts a perspective view of the power tool and the battery pack of FIG. 69 with a housing half of the power tool removed.[000115] FIG. 73 depicts another perspective view of the power tool and the battery pack of FIG.69 with the housing half of the power tool removed.[000116] FIG. 74 depicts a side view of the power tool and the battery’ pack of FIG. 69 with the housing half of the power tool removed.[000117] FIG. 75 depicts a perspective view of the power tool of FIG. 69.[000118] FIG. 76 depicts a bottom perspective view of the power tool of FIG. 69.[000119] FIG. 77 depicts a partial perspective view of the power tool of FIG. 69 with the housing half removed.[000120] FIG. 78 depicts a partial bottom perspective view of the power tool of FIG. 69 with the housing half removed.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000121] FIG. 79 depicts a perspective view of the power tool of FIG. 69 and an adaptor.[000122] FIG. 80 depicts a perspective view of the power tool, the adaptor, and a sliding battery pack mounted to the adaptor of FIG. 79.[000123] FIG. 81 depicts a perspective view of the adaptor and the sliding battery pack of FIG.80 detached from the power tool.[000124] FIG. 82 depicts a perspective view of a power tool in accordance with the disclosure having an elongated body.[000125] FIG. 83 depicts another perspective view of the power tool of FIG. 82.[000126] FIG. 84 depicts a perspective view of the power tool of FIG. 82 with a housing half removed.[000127] FIG. 85 depicts a perspective view of the power tool of FIG. 82 and the battery pack with the housing half removed.[000128] FIG. 86 depicts a perspective view of the power tool of FIG. 82 and the adaptor with the housing half removed.[000129] FIG. 87 depicts a rear perspective view of the battery pack of FIG. 69.[000130] FIG. 88 depicts a front perspective view of the battery pack of FIG. 69.[000131] FIG. 89 depicts a rear exploded view of the battery pack of FIG. 69.[000132] FIG. 90 depicts a front exploded view of the battery pack of FIG. 69.[000133] FIG. 91 depicts a partial exploded view of a cell holder and battery cells of the battery’ pack of FIG. 69.[000134] FIG. 92 depicts another partial exploded view of the cell holder and battery' cells of the battery’ pack of FIG. 69.[000135] Throughout this specification and figures like reference numbers identify like elements.DETAILED DESCRIPTION[000136] Although certain embodiments and examples are described below, it will be understood that the disclosure extends beyond the specifically disclosed embodiments and / or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure herein disclosed should not be limited by any particular embodiments described below.[000137] FIG. 1, FIG. 2, FIG. 3, and FIG. 4 illustrate views of a power tool 10 in accordance with embodiments of the present disclosure. The power tool 10 includes a power train assembly 11 and a handle assembly 12 extending from the power train assembly 11. The power tool 10 is shown as a handheld, battery-powered tool having a removable battery’ pack 1800 at least partially- received within the handle assembly 12. In the illustrated embodiment, the handle assembly 12 and the battery pack 1800 together define a composite grip region 191 configured to be engaged by a user during operation.[000138] FIG. 1 illustrates a perspective view of the power tool 10 in an assembled configuration with a battery pack 1800 coupled thereto. As described herein, the power tool 10 is configured to be selectively couplable with any of a plurality’ of battery- power sources, including the battery¬ pack 1800 (for example, as show n in FIGS. 19A-19F), the battery pack 500 (for example, as shownP-WO-TN-2025-0009 / / 1076-0022WO Patent in FIGS. 6A-6F), or one or more adapters, such as adapter 2600 or adapter 2700, configured to interface between the power tool 10 and different battery pack form factors.[000139] The power train assembly 11 generally defines an upper body of the power tool 10 and can support the output assembly 16. The power train assembly 11 houses an electric motor configured to rotatably drive the output member 18 via one or more gear assemblies and / or hammer mechanisms. The output member 18 can be configured to support or be coupled to a working implement, accessory, or tool attachment depending on the configuration of the power tool 10. In the illustrated embodiment, the output member 18 extends along a motor axis 17, which can correspond to an axis of rotation or motion of the output assembly 16. The output assembly 16 can be configured to provide rotational output, reciprocating output, percussive output, or combinations thereof. As shown in FIG. 3, the power train assembly 11 is separable from the handle assembly 12, and although illustrated with a particular output configuration, can accommodate different motor types, output orientations, or drive mechanisms while maintaining the overall architectural relationships shown in FIG. 1.[000140] The handle assembly 12 extends downwardly from the power train assembly 11 and defines a handle axis 19 that is transverse to the motor axis 17. A trigger assembly 22 is positioned along a forward-facing surface of the handle assembly 12 and is configured to be actuated by a user to control operation of the power tool 10. The trigger assembly 22 is movable relative to the handle assembly 12 along a trigger direction axis 9.[000141] In some embodiments, the power tool 10 may include a motor, an output member, and associated drive and control components that correspond to or are implemented in accordance with motor configurations, output assemblies, gear trains, and / or hammer mechanisms of the ty pe disclosed in U.S. Patent No. 11,705,778, titled “Power Tool with Compact Motor Assembly,” issued on July 18, 2023, and assigned to Black & Decker Inc., which is hereby incorporated by reference in its entirety for all purposes. The incorporation of U.S. Patent No. 11,705,778 is provided to illustrate non-limiting examples of motor and output assembly implementations that may be employed in the power tool 10 and is not intended to limit the present disclosure to any particular motor configuration, component location, or drive arrangement.[000142] The handle assembly 12 defines an exterior grip surface including a first grip surface 112 arranged to be engaged by a user’s hand during operation. The handle assembly 12 further includes an upper handle region 113 adjacent the power train assembly 11 and a lower handle region 114 configured to receive a battery pack. In the battery-installed configuration shown in FIG. 1, the battery pack 1800 includes a second housing portion 1806 positioned externally of the handle assembly 12 such that exterior surfaces of the second housing portion 1806 cooperate with exterior surfaces of the handle assembly 12 to define a portion of the composite grip region 191.[000143] In some embodiments, aspects of the handle-integrated grip architecture described herein, including body -grip configurations in which the handle assembly 12 and the battery pack 1800 together define an elongate, user-engageable grip region extending along a longitudinal direction of the tool, may be implemented in accordance with the power tool housing and body-P-WO-TN-2025-0009 / / 1076-0022WO Patent grip configurations described in International Patent Application No. WO2025137119A1, which is hereby incorporated by reference in its entirety for all purposes.[000144] In some embodiments, aspects of the grip geometry’, finger engagement regions, and / or ergonomic contouring of the handle assembly 12 and the battery pack 1800 forming the composite grip region 191 may be implemented in accordance with the handle and handgrip configurations described in U.S. Patent No. 10,350,744 B2, patented June 26. 2019, titled "Ergonomic handle for power tool,” including multi-region grip surfaces tailored for finger and palm engagement, and U.S. Patent No. 12,233,526 B2, patented July 24, 2023, titled ‘‘Power tool with ergonomic handgrip,” including front, rear, and sidewall gripping regions arranged relative to a trigger axis, each of which is hereby incorporated by reference in its entirety7for all purposes.[000145] The battery pack 1800 can supply electrical pow er to internal assemblies of the power tool 10 when installed. In some embodiments, the battery pack 1800 includes a plurality7of battery cells arranged in series, parallel, or series-parallel configurations to provide a nominal voltage and capacity suitable for operating the power tool. In some cases, the battery pack 1800 includes five battery cells electrically connected in series, with each battery cell having a nominal cell voltage of approximately 3.6 to 4.2 volts, such that the battery pack 1800 provides anominal output voltage of approximately 18 to 20 volts and / or a maximum output voltage of approximately 20 to 25 volts. In other embodiments, the battery pack 1800 may include fewer or greater numbers of battery cells, or different series or parallel groupings, depending on desired power output, runtime, and tool application.[000146] In some embodiments, the battery pack 1800 includes a plurality of series-connected lithium-ion battery cells providing anominal pack voltage greater than approximately 14 volts. In some embodiments, the battery’ pack nominal voltage is between approximately 17.5 volts and approximately 22.5 volts. In some embodiments, the power tool 10 includes an electric motor and associated control circuitry7configured to operate at an operating voltage greater than approximately 14 volts, and the handle assembly 12 and internal electrical architecture of the power tool 10 are configured to receive electrical power from the battery’ pack 1800 at such voltage levels.[000147] Although the power tool 10 is illustrated and described herein as a cordless, battery-powered tool utilizing a handle-integrated battery pack 1800, other power supply configurations may be employed in some embodiments. For example, the battery pack 1800 may utilize different battery chemistries, voltage classes, or cell arrangements, including but not limited to lithium-ion battery packs configured to provide nominal output voltages greater or less than those described herein. In other embodiments, the power tool 10 may be configured for operation using an external power source, such as an AC power supply, with electrical power supplied to the power tool 10 through a power cord or other external electrical interface. Such variations may be implemented without departing from the structural, ergonomic, and modular principles described herein.[000148] In the configuration illustrated in FIG. 1, the handle assembly 12 provides a portion of the composite grip region 191, w ith the battery7pack 1800 forming a complementary portion when installed. This cooperative relationship betw een the handle assembly 12 and the battery pack 1800P-WO-TN-2025-0009 / / 1076-0022WO Patent can allow grip geometry, balance, and ergonomic characteristics of the power tool 10 to be influenced by the configuration of the battery pack 1800. In some embodiments, a rear surface of the handle assembly 12 includes a recessed and contoured region configured to engage a thenar region of a user's hand, while an upper rear portion of the battery pack 1800 provides a rear engagement surface configured to support a proximal palmar region of the user's hand. In some embodiments, when a user grips the composite grip region 191 with an index finger engaging the trigger 22, at least one lower finger of the user’s hand engages the second housing portion 1806 of the battery pack 1800.[000149] Although the power tool 10 is illustrated in FIG. 1 as a handheld, battery -powered tool, the illustrated arrangement is not limited to a particular tool type. The power tool 10 can be configured as, for example, a drill, impact driver, impact tool, grinder, saw, or other powered hand tool. The relative arrangement of the handle assembly 12, power train assembly 11, output assembly 16, and battery pack 1800 can vary depending on application, operating mode, or platform configuration while maintaining a handle-integrated battery architecture in which the battery pack forms part of a user grip.[000150] FIG. 2 illustrates a perspective view of the power tool 10 with the battery pack 1800 separated from the handle assembly 12 and positioned for insertion along a battery insertion axis 21 relative to the handle assembly 12. The handle assembly 12 defines a battery receptacle cavity 115 positioned within the lower handle region 114 and configured to receive at least a portion of the battery pack 1800.[000151] The battery pack 1800 includes a battery housing 1802 having a first housing portion 1804 configured to be at least partially received within the battery receptacle cavity 115 of the handle assembly 12 and a second housing portion 1806 configured to remain external to the handle assembly 12 when the battery’ pack 1800 is installed. The first housing portion 1804 and the second housing portion 1806 are arranged along the battery insertion axis 21, with the first housing portion 1804 having a smaller transverse dimension than the second housing portion 1806.[000152] When the battery pack 1800 is installed into the battery receptacle cavity 115, exterior surfaces of the handle assembly 12 and exterior surfaces of the second housing portion 1806 cooperate along the handle axis 19 to form the composite grip region 191. In use, a user gripping the power tool 10 engages the handle assembly 12 and the battery pack 1800, such that the battery pack 1800 operates as an extension of the handle assembly 12 during normal operation.[000153] FIG. 3 illustrates an exploded perspective view of the power tool 10 with the battery pack 1800 removed, showing separation between the power train assembly 11 and the handle assembly 12 along a power train assembly attachment axis 23. The power train assembly attachment axis 23 defines an assembly and disassembly direction used during manufacturing, initial assembly, or servicing of the power tool 10, along which the power train assembly 11 is attachable to and removable from the handle assembly 12.[000154] The handle assembly 12 is configured as a structural and functional core of the power tool 10 and supports internal mechanical, electrical, and control assemblies. The handle assembly 12 defines the battery7receptacle cavity 115 and supports interfaces for electrical coupling betweenP-WO-TN-2025-0009 / / 1076-0022WO Patent the battery pack 1800 and internal components of the power tool 10. The power train assembly 11 is configured as a discrete module that supports motor and output components associated with the output assembly 16 and the output member 18.[000155] FIG. 4 illustrates a cross-sectional view of the power tool 10 with no battery pack installed. In this view, internal components of the power train assembly 11 are shown arranged along the motor axis 17 within the motor housing 16. These components are supported within the power train assembly 11 and are arranged to transmit mechanical output to the output member 18 positioned at a forw ard end of the power tool 10.[000156] In some embodiments, aspects of motor construction and bearing retention structures may be implemented in accordance with the brushless motor and axial post insert arrangements described in U.S. Patent No. 10,727,715 B2, titled “Brushless motor with axial post inserts for bearing retention,” which teaches examples of axial post inserts configured to retain bearings and improve alignment of rotor and stator assemblies, and which is hereby incorporated by reference in its entirety for all purposes.[000157] In some embodiments, aspects of brushless motor packaging and electrical connection features may be implemented in accordance with the inline stator terminal arrangements described in U.S. Patent No. 12.088,160 B2, titled “Brushless motor with inline stator terminals,” which teaches motor configurations where stator terminals are arranged along an axis of the motor to reduce envelope size and simplify electrical packaging, and which is hereby incorporated by reference in its entirety for all purposes.[000158] In some embodiments, aspects of compact module architecture for motor and drivetrain assemblies configured for pistol-grip tools may be implemented in accordance with the SBS module and compact powertrain arrangements described in U.S. Patent No. 11,095,193 B2, titled “SBS module as used in pistol grip tools,” which teaches discrete motor, gear train, and interface assemblies sized for integration within pistol-grip tool bodies, and which is hereby incorporated by reference in its entirety for all purposes.[000159] In some embodiments, aspects of compact motor implementation within a body-grip tool architecture may be implemented in accordance with the motor and housing configurations described in U.S. Patent No. 11,855,521 B2, titled “Brushless DC motor for a body-grip power tool,” which teaches examples of a brushless DC motor with stator, rotor, bearing support structures, and control circuitry at least partially contained within a grip portion of a tool housing, and which is hereby incorporated by reference in its entirety for all purposes.[000160] In some embodiments, a partition wall 30 is positioned between an upper end of the handle assembly 12 and a lower end of the power train assembly 11, at an interface between the handle assembly 12 and the power train assembly 11. The partition wall 30 provides structural support and separates motor and drivetrain components supported within the power train assembly 11 from electrical and control components supported within the handle assembly 12. A trigger assembly 22 is positioned adjacent and forward of the partition wall 30 for engagement by a user’s index finger when the handle assembly 12 is grasped. Actuation of the trigger assembly 22 alongP-WO-TN-2025-0009 / / 1076-0022WO Patent a trigger direction axis 9 generates a control input for operation of the motor, and in some embodiments provides variable-speed control as a function of trigger travel.[000161] As further shown in FIG. 4, the handle assembly 12 supports internal electrical and control components positioned below the power train assembly 11. In the illustrated embodiment, a PCB 3222 is positioned within the handle assembly 12 adjacent the battery receptacle cavity 115. The PCB 3222 supports control electronics and power switching components configured to control operation of the motor supported within the power train assembly 11. The PCB 3222 is oriented generally transverse to the handle axis 19 and positioned such that electrical coupling to motor-related components is achieved without routing extended wiring through the handle assembly 12. In some embodiments, the PCB 3222 is positioned in close proximity to the trigger assembly 22 to permit direct electrical coupling of trigger-generated control signals without intervening wiring.[000162] The handle assembly 12 further supports tool-side battery terminals positioned ithin the battery receptacle cavity 115 and arranged to electrically mate with corresponding battery terminals of the battery pack 1800 when installed. One or more bus capacitors are positioned adjacent the battery terminal region within the handle assembly 12 and are electrically coupled between the battery terminals and the PCB 3222. In some embodiments, electrical coupling between the batten’ terminals, the bus capacitors, and the PCB 3222 is established through rigid conductors or fixed terminal structures rather than flexible wiring.[000163] In the configuration shown in FIG. 4, the battery’ terminal region, bus capacitors, and PCB 3222 are co-located within a common internal region of the handle assembly 12. This arrangement reduces electrical path length between energy storage, power conditioning, and control electronics, supports compact packaging of high-current electrical components, and facilitates a modular architecture in which electrical and control components remain fixed relative to the handle assembly 12 independent of the pow er train assembly 11.Example Battery Pack Architecture[000164] Battery packs for cordless power tools are commonly designed as removable electrical power sources that are mechanically and electrically coupled to a tool handle but may be treated as self-contained components, separate from the overall structural and ergonomic architecture of the tool. In many conventional designs, the battery pack geometry', internal cell arrangement, and electrical interface placement are dictated primarily by packaging constraints or legacy form factors, with limited coordination between external grip geometry, internal cell layout, and the spatial organization of components within the power tool handle.[000165] As a result, conventional battery’ packs may function primarily as appended power modules rather than as integrated portions of the tool structure. Such arrangements can lead to discontinuities in grip profile, suboptimal w eight distribution, inefficient use of handle volume, and / or increased electrical path lengths betyveen the battery’ pack and internal control or motor components. These factors can negatively affect user comfort, balance, control, and overall system efficiency, particularly in compact or high-performance poyver tools.[000166] Additionally, many battery’ pack designs employ internal cell arrangements that are constrained to uniform orientations or stacked configurations that do not readily accommodateP-WO-TN-2025-0009 / / 1076-0022WO Patent ergonomic handle geometries or modular tool architectures. Such constraints can limit the ability to position the battery’ pack's mass within the handle, increase reliance on external battery volume, and restrict opportunities to optimize electrical interconnection architecture, terminal placement, or proximity to internal control circuitry.[000167] To address these or other challenges, some aspects of the present disclosure relate to battery pack architectures that are intentionally configured as integrated system components, in which external housing geometry', internal battery cell arrangement, and electrical interconnection architecture are coordinated with the handle assembly and internal layout of a power tool. In some embodiments, the battery’ pack is configured to function not only as a removable electrical power source but also as a structural and ergonomic extension of the handle assembly when installed.[000168] In some embodiments, the battery pack includes multiple housing regions having different functional roles, including an insertable housing region configured to be received within a battery receptacle cavity of the handle assembly and an external housing region configured to remain outside the handle assembly and define a user-engageable grip surface. Internal battery cells may be arranged such that one or more battery cells are positioned at least partially within the handle assembly when the battery pack is installed, while one or more other battery cells remain external to the handle assembly, thereby distributing the battery pack’s mass across internal and external regions of the tool.[000169] In some embodiments, internal battery cells are arranged in multiple axially separated cell groups, which may include cells oriented parallel to, offset from, or non-parallel to an insertion axis of the battery pack. Such arrangements may facilitate efficient use of available internal volume, facilitate ergonomic external housing contours, and / or support compact battery' pack geometries while maintaining desired electrical capacity' and voltage characteristics.[000170] In some embodiments, the battery' pack includes an internal support and electrical interconnection structure that positions battery' cells in predetermined spatial relationships selected to shorten conductor routing between adjacent battery cells in a series electrical circuit. By orienting and spatially locating the battery cells to reduce the total collective length of conductors required for electrical interconnection, the architecture can reduce the number of conductors extending along side surfaces of the battery cells, reduce electrical resistance, and facilitate compact, manufacturable internal battery pack designs.[000171] In some embodiments, electrical terminals of the battery pack are positioned at a toolfacing end of the pack housing and arranged to electrically couple with corresponding terminals of the power tool when the battery’ pack is installed. The terminals may be positioned to extend into an interior region of the handle assembly adjacent internal control components, switching elements, or a common circuit board of the power tool, such that electrical coupling is established through direct connectorized interfaces rather than wire harnesses. This configuration can shorten electrical path length, reduce or eliminate intervening wiring, and support compact, integrated electrical architectures within the power tool.[000172] FIGS. 5A, 5B, 5C, 5D, 5E, and 5F illustrate the power tool 10 of FIG. 1, showing orthogonal views of the power tool 10 with a battery' pack 500 coupled thereto. Collectively, theseP-WO-TN-2025-0009 / / 1076-0022WO Patent views illustrate the external geometry, handle integration, and ergonomic relationship between the handle assembly 12 and the battery pack 500 in an installed configuration. In particular, FIGS. 5A, 5B. 5C, 5D, 5E, and 5F illustrate a left-side elevation view, a front elevation view, a right-side elevation view, a rear elevation view, a top elevation view, and a bottom elevation view, respectively, of the power tool 10 and the battery' pack 500.[000173] Referring to FIGS. 5A-5F. the power tool 10 includes a handle assembly 12 and a power train assembly 11 coupled to the handle assembly 12. The power train assembly 11 is configured to house an electric motor and associated drive components and defines an output axis 17. The handle assembly 12 includes a user-engageable grip surface or partial grip surface extending generally along a handle axis 19. The handle assembly 12 further supports user-actuatable controls, including a trigger 22, and internal electrical and control components.[000174] As described herein, the power tool 10 establishes a modular architecture in which the handle assembly 12 provides a structural core for the power tool 10, and the power train assembly 11 forms a distinct non-handle assembly configured to be coupled to the handle assembly 12 as part of a unified power tool assembly. In such an architecture, different power train assemblies, and / or portions thereof, may be selectively paired with the handle assembly 12 during design, manufacturing, or assembly as a common handle assembly, thereby supporting a scalable platform across multiple power tool variants.[000175] Shown in an installed configuration in FIGS. 5A-5F, the battery pack 500 is removably coupled to the handle assembly 12 and extends along a pack longitudinal axis 523. Although illustrated as being substantially coincident w ith the handle axis 19 and with the insertion axis 521 along which the battery pack 500 is received into the power tool 10, it will be appreciated that the pack longitudinal axis 523, the handle axis 19, and the insertion axis 521 may vary in relative orientation across different embodiments. In some embodiments, the pack longitudinal axis 523, the handle axis 19, and the insertion axis 521 are generally parallel to one another. In some cases, one or more of the pack longitudinal axis 523, the handle axis 19, and the insertion axis 521 may be angularly offset relative to one another by a small amount while remaining generally aligned. By way of non-limiting example, the pack longitudinal axis 523 may be oriented within approximately -10 degrees to +10 degrees relative to the handle axis 19 and / or the insertion axis 521. Similarly, the handle axis 19 may be oriented within approximately -10 degrees to +10 degrees relative to the pack longitudinal axis 523 and / or the insertion axis 521.[000176] In the illustrated embodiment, the pack housing 502 includes a first housing portion (not visible in FIGS. 5A-5F) configured to be received within a battery receptacle cavity of the handle assembly 12, and a second housing portion 506 configured to remain external to the handle assembly 12 when the battery pack 500 is installed. The second housing portion 506 defines an external grip section of the battery pack 500 that is dimensioned and contoured to be grasped by a user in combination with the handle assembly 12.[000177] As seen at least in FIGS. 5A-5D, a transitional region 508 is positioned between an exterior envelope of the handle assembly 12 and an exterior envelope of the second housing portionP-WO-TN-2025-0009 / / 1076-0022WO Patent 506 of the baten’ pack 500. The transitional region 508 defines or corresponds to a change in the exterior profile of the assembled handle and batery structure.[000178] In some embodiments, the transitional region 508 defines a substantially seamless transition between the handle assembly 12 and the second housing portion 506. such that the transition is visually and tactually continuous. In other embodiments, the transitional region 508 defines a discernible interface, seam, joint line, or boundary indicative of separate components or housing portions. In some cases, such a discernible interface results from differences between the handle assembly 12 and the pack housing 502, including differences in material, thickness, manufacturing process, tolerance, or assembly method. In some embodiments, the transitional region 508 includes a localized reduction, step, relief, shoulder, or contour variation relative to adjacent grip surfaces, rather than forming a uniform or planar continuation.[000179] Referring to FIGS. 5A-5D, the handle assembly 12 and the second housing portion 506 of the batery pack 500 collectively define a composite grip region 591 extending generally along the handle axis 19. The composite grip region 591 includes an upper grip region 532 defined primarily by the handle assembly 12, a lower grip region 534 defined primarily by the second housing portion 506 of the batery pack 500. and a transition grip region 536 positioned at the transitional region 508.[000180] The upper grip region 532 is configured to be engaged by a proximal portion of a user’s hand during operation of the power tool 10. while the lower grip region 534 is configured to be engaged by a distal portion of the user’s hand. In an operating grip configuration, portions of the user’s hand may simultaneously engage both the upper grip region 532 and the lower grip region 534, such that the handle assembly 12 and the battery pack 500 function together as a single functional gripping structure.[000181] The transition grip region 536 defines an interface zone between the handle assembly 12 and the second housing portion 506 and may include localized contour variations, curvature changes, reliefs, or stepped features relative to adjacent grip surfaces. In some embodiments, the transition grip region 536 accommodates geometric differences between the handle assembly 12 and the batery pack 500 while permiting the user’s hand to span the interface therebetween without requiring a change in grip position during normal operation of the power tool 10.[000182] In some anatomy-aware embodiments, the composite grip region 591 includes a thenar support region 540 positioned along a rearward portion of the handle assembly 12, proximal to the power train assembly 11. The thenar support region 540 may define a curved, recessed, or contoured surface configured to engage or support a thenar region of a user’s hand when the power tool 10 is grasped. In such configurations, the thenar support region 540 cooperates with the upper grip region 532 to stabilize hand placement while permitting a trigger finger of the user to extend forwardly to engage the trigger 22.[000183] In an operating grip configuration, remaining fingers of the user’s hand are positioned to grasp portions of the composite grip region 591 such that at least one finger engages the upper grip region 532 defined by the handle assembly 12 and at least one finger engages the lower grip region 534 defined by the second housing portion 506 of the batery pack 500. In someP-WO-TN-2025-0009 / / 1076-0022WO Patent embodiments, two or more fingers of the user’s hand engage the handle assembly 12 while one or more additional fingers engage the battery pack 500. In some embodiments, two or more fingers of the user’s hand engage the battery pack 500 while one or more additional fingers engage the handle assembly 12.[000184] In some cases, the number of fingers engaging the handle assembly 12 and the number of fingers engaging the battery pack 500 varies depending on hand size, grip posture, or user preference. For example, users with larger hands may engage a greater number of fingers on the battery pack 500, while users with smaller hands may engage a greater number of fingers on the handle assembly 12, or vice versa.[000185] In such arrangements, the user’s hand spans the transition grip region 536, allowing gripping forces and operational reaction forces to be distributed across both the handle assembly 12 and the battery pack 500. This multi-region engagement enables the handle assembly 12 and the battery pack 500 to function together as a unified gripping structure while accommodating variations in hand size, finger placement, and grip posture during operation of the power tool 10.[000186] In some embodiments, the handle assembly 12 and the second housing portion 506 have exterior dimensions that are generally similar in scale such that, when assembled, the handle assembly 12 and the battery pack 500 collectively define a composite grip region 591 capable of being engaged by a user as a single functional gripping structure. In such configurations, adjacent exterior surfaces of the handle assembly 12 and the second housing portion 506 are sized and positioned to permit a user’s hand to span an interface therebetween without requiring a change in grip position or hand posture during normal operation of the power tool 10.[000187] In some embodiments, a perimeter of the second housing portion 506, measured in a plane generally transverse to the handle axis 19 at or near a region of user engagement, is similar to a corresponding perimeter of an adjacent portion of the handle assembly 12. For example, the perimeter of the second housing portion 506 may be within approximately 70% to approximately 130%, 80% to approximately 120%, 85% to approximately 115%, 90% to approximately 110%, or 95% to approximately 105% of the corresponding perimeter of the handle assembly 12. In some embodiments, such perimeter similarity is maintained over at least a portion, a majority portion, or substantially an entirety of an axial length of the assembled handle assembly 12 and battery pack 500.[000188] In some embodiments, a width and / or thickness of the second housing portion 506 is similar to a width and / or thickness of an adjacent portion of the handle assembly 12. As used herein, width and thickness may refer to maximum exterior dimensions measured in orthogonal directions transverse to the handle axis 19 at a location corresponding to a primary user grip region. By way of example, a maximum width, thickness, or both of the second housing portion 506 may be within approximately 70% to approximately 130%, 80% to approximately 120%, 85% to approximately 115%, 90% to approximately 110%, or 95% to approximately 105% of a corresponding maximum width, thickness, or both of the handle assembly 12.[000189] In some embodiments, a largest cross-sectional area of the second housing portion 506, taken in a plane generally transverse to the handle axis 19, is comparable to a largest cross-P-WO-TN-2025-0009 / / 1076-0022WO Patent sectional area of the handle assembly 12. For example, the largest cross-sectional area of the second housing portion 506 may differ from that of the handle assembly 12 by no more than approximately 30%, 20%, 15%, 10%, or 5%. In such configurations, the handle assembly 12 and the battery pack 500 are collectively sized to support load transfer, resistance to operational reaction forces, and sustained manual engagement across the interface therebetween, notwithstanding localized variations in contour, transition geometry, or surface profile.[000190] In some embodiments, a rate of change of at least one exterior dimension of the second housing portion 506 along an axial direction is similar to a rate of change of a corresponding exterior dimension of the handle assembly 12. For example, a change in perimeter, width, thickness, or effective cross-sectional dimension of the second housing portion 506 per unit axial length may be within approximately 70% to approximately 130%, 80% to approximately 120%, 90% to approximately 110%, or 95% to approximately 105% of a corresponding rate of change of the handle assembly 12. In such embodiments, the handle assembly 12 and the battery pack 500 exhibit comparable axial tapering or contour progression, which contributes to a grip geometry that accommodates the user’s hand across the interface therebetween notwithstanding localized contour variations at the transitional region 508.[000191] FIGS. 6A, 6B, 6C, 6D. 6E. and 6F illustrate left-side elevation, front elevation, rightside elevation, rear elevation, top elevation, and bottom elevation views, respectively, of a battery¬ pack 500 in accordance with the present disclosure. As shown, the battery pack 500 includes a pack housing 502 defining an elongate body extending along a pack longitudinal axis 523. The pack housing 502 includes a first housing portion 504, a second housing portion 506 arranged generally along the pack longitudinal axis 523, a transitional region 508 positioned between the first housing portion 504 and the second housing portion 506, a lower base portion 525 positioned adjacent a lower end 522 of the pack housing 502, and a set of battery- pack electrical terminals 526 positioned at an upper end 520 of the pack housing 502 for electrical coupling with a power tool 10.[000192] The pack housing 502 has an axial height Hl measured generally parallel to the pack longitudinal axis 523 between the upper end 520 and the lower end 522, with the axial height Hl corresponding to an overall length of the battery pack 500. In the illustrated embodiments, the first housing portion 504 and the second housing portion 506 are arranged generally along the pack longitudinal axis 523, with the first housing portion 504 configured to be received at least partially within a battery- receptacle cavity- of the handle assembly 12 of the power tool 10 and the second housing portion 506 configured to remain exposed when the battery pack 500 is installed. In some embodiments, the first housing portion 504 and the second housing portion 506 are generally- aligned along the pack longitudinal axis 523, while in other embodiments their respective longitudinal axes are offset by up to approximately -10 degrees to +10 degrees while remaining generally- aligned.[000193] As show n in FIG. 6A, the first housing portion 504 has a first transverse dimension T1 measured generally orthogonal to the pack longitudinal axis 523, and the second housing portion 506 has a second transverse dimension T2 measured generally orthogonal to the pack longitudinalP-WO-TN-2025-0009 / / 1076-0022WO Patent axis 523. The batery pack 500 may present a reduced transverse profile in the first housing portion 504 to facilitate insertion into the handle assembly 12 and an increased transverse profile in the second housing portion 506 to define a user-engageable external grip section.[000194] In some embodiments, the first transverse dimension T1 and the second transverse dimension T2 each refer to a maximum exterior extent of the corresponding housing portion measured orthogonal to the pack longitudinal axis 523 along a selected measurement direction. In some embodiments, the selected measurement direction is consistent across the first housing portion 504 and the second housing portion 506 such that T1 and T2 are directly comparable in a common orientation. The transverse dimensions T1 and T2 are not limited to diameters, radii, or other values associated with circular cross-sections and may instead correspond to widths, thicknesses, or effective outer envelopes of housing portions having non-circular, oval, faceted, lobed, asymmetric, or compound cross-sectional shapes.[000195] In some embodiments, a "width" of a given housing portion refers to a largest side-to-side exterior dimension of that housing portion when viewed from a front or rear elevation, such as the dimension a user would perceive as the left-to-right span of the batery pack when viewing FIG. 6B. In some embodiments, a “thickness” refers to a largest front-to-back exterior dimension of the housing portion when viewed from a side elevation, such as the dimension a user would perceive as the depth of the batery pack when view ing FIG. 6A or FIG. 6C. Both the width and the thickness are measured in directions orthogonal to the pack longitudinal axis 523 and may be taken at a reference axial location corresponding to a primary' grip region or insertion region. Accordingly, the transverse dimensions T1 and T2 represent effective transverse dimensions of the respective housing portions rather than being limited to any single geometric orientation.[000196] Referring to FIGS. 6B and 6C, the first housing portion 504 has a maximum width XI (FIG. 6B) and a maximum thickness Yl (FIG. 6C), and the second housing portion 506 has a maximum width X2 (FIG. 6B) and a maximum thickness Y2 (FIG. 6C). In some embodiments, XI corresponds to a maximum exterior dimension of the first housing portion 504 measured along a first transverse direction orthogonal to the pack longitudinal axis 523, such as a side-to-side direction as viewed in the front elevation of FIG. 6B. Similarly, X2 corresponds to a maximum exterior dimension of the second housing portion 506 measured along that same transverse direction.[000197] In some embodiments, Yl corresponds to a maximum exterior dimension of the first housing portion 504 measured along a second transverse direction orthogonal to the pack longitudinal axis 523 and orthogonal to the first transverse direction, such as a front-to-back direction as viewed in the right-side elevation of FIG. 6C. Likewise, Y2 corresponds to a maximum exterior dimension of the second housing portion 506 measured along that same second transverse direction. In this manner, XI and Yl represent orthogonal transverse dimensions of the first housing portion 504, and X2 and Y2 represent orthogonal transverse dimensions of the second housing portion 506.[000198] In some embodiments, the first transverse dimension T1 corresponds to one of XI or Yl, or to a maximum of XI and Yl. Similarly, the second transverse dimension T2 mayP-WO-TN-2025-0009 / / 1076-0022WO Patent correspond to one of X2 or Y2, or to a maximum of X2 and Y2. In other embodiments, T1 and T2 correspond to effective transverse dimensions derived from Xl / Yl and X2 / Y2, respectively, such as equivalent dimensions based on perimeter, cross-sectional area, or other geometric characterizations of the housing portions.[000199] In some embodiments, the second transverse dimension T2 of the second housing portion 506 is greater than the first transverse dimension T1 of the first housing portion 504. This dimensional relationship reflects a reduced transverse profile of the first housing portion 504 configured for receipt within the handle assembly 12 of the power tool 10 and an enlarged transverse profile of the second housing portion 506 configured to define a user-engageable external grip section when the battery pack 500 is installed.[000200] In some embodiments, the second transverse dimension T2 is greater than the first transverse dimension T1 by at least approximately 5%, 10%, 15%, 20%, 25%, or 30%. In some embodiments, the second transverse dimension T2 is between approximately 105% and approximately 200% of the first transverse dimension Tl, or between approximately 110% and approximately 160% of the first transverse dimension Tl.[000201] Referring again to FIGS. 6B and 6C, in some embodiments the maximum width X2 of the second housing portion 506 is greater than the maximum width XI of the first housing portion 504. In some embodiments, X2 exceeds XI by at least approximately 5%, 10%, 15%, or 20%. In some embodiments, X2 is between approximately 105% and approximately 150% of XI, or between approximately 110% and approximately 130% of XI.[000202] In some embodiments, the maximum thickness Y2 of the second housing portion 506 is greater than the maximum thickness Y1 of the first housing portion 504. In some embodiments, Y2 exceeds Yl by at least approximately 5%, 10%, 15%, or 20%. In some embodiments, Y2 is between approximately 105% and approximately 1 0% of Yl, or between approximately 110% and approximately 140% of Yl.[000203] In some embodiments, both the width and the thickness of the second housing portion 506 exceed the corresponding width and thickness of the first housing portion 504, such that X2 > XI and Y2 > Yl. In other embodiments, only one of the width or the thickness of the second housing portion 506 exceeds that of the first housing portion 504 while the other dimension remains similar or substantially similar.[000204] In some embodiments, a ratio of X2 to XI differs from a ratio of Y2 to Yl, such that the transverse expansion from the first housing portion 504 to the second housing portion 506 is anisotropic rather than uniform in all transverse directions. In such embodiments, the second housing portion 506 may be selectively enlarged more in one transverse direction than in another, rather than being scaled uniformly relative to the first housing portion 504. By way of non-limiting example, the second housing portion 506 may be widened to a greater extent in a side-to-side direction (e.g., increasing X2 relative to XI) while being increased by a lesser amount in a front-to-back direction (e.g., Y2 relative to Yl), or vice versa.[000205] In some embodiments, a cross-sectional area of the second housing portion 506, taken in a plane orthogonal to the pack longitudinal axis 523, is greater than a cross-sectional area of theP-WO-TN-2025-0009 / / 1076-0022WO Patent first housing portion 504 taken in a corresponding plane. In some embodiments, the cross-sectional area of the second housing portion 506 exceeds that of the first housing portion 504 by at least approximately 10%, 20%, 30%. or 40%. In some embodiments, the cross-sectional area of the second housing portion 506 is between approximately 110% and approximately 200% of the cross-sectional area of the first housing portion 504.[000206] In some embodiments, a perimeter of the second housing portion 506, measured in a plane orthogonal to the pack longitudinal axis 523, is greater than a perimeter of the first housing portion 504 measured in a corresponding plane. In some embodiments, the perimeter of the second housing portion 506 exceeds the perimeter of the first housing portion 504 by at least approximately 5%, 10%, 15%, or 20%.[000207] In some embodiments, one or more transverse dimensions of the first housing portion 504 and / or the second housing portion 506 are non-uniform within the respective housing portion. For example, XI, Yl, and / or T1 may vary along an axial direction of the first housing portion 504, and X2, Y2, and / or T2 may vary along an axial direction of the second housing portion 506, rather than remaining constant over the entire axial extent of the respective housing portion.[000208] In some embodiments, such variation may occur gradually or discretely and may be provided to accommodate internal component geometry, structural requirements, ergonomic shaping, or interface geometry with the handle assembly 12. By way of non-limiting example, the second housing portion 506 may include localized enlargements, tapers, recesses, or contour transitions along its length while still defining an overall transverse envelope that is greater than that of the first housing portion 504.[000209] In some embodiments, transverse dimensions of the first housing portion 504 and / or the second housing portion 506 may vary across different transverse directions at a given axial location, such that the housing portions do not exhibit uniform cross-sectional geometry. In such embodiments, XI and Yl, and / or X2 and Y2, may differ from one another at the same axial location, and may further vary along the axial length, while remaining within the comparative relationships described herein.[000210] With continued reference to FIGS. 6A to 6F, the transitional region 508 is positioned between the first housing portion 504 and the second housing portion 506 of the pack housing 502 and defines a geometric transition between portions of the pack housing 502 having different transverse envelopes. In this manner, the transitional region 508 separates a portion of the pack housing 502 primarily configured for insertion and retention within the handle assembly 12 of the power tool 10 from a portion of the pack housing 502 primarily configured for external gripping and user engagement.[000211] In some embodiments, the transitional region 508 defines a stepped surface 510 extending generally outward relative to the pack longitudinal axis 523, such that the second housing portion 506 projects transversely beyond the first housing portion 504. When the battery pack 500 is fully seated within the handle assembly 12, the stepped surface 510 may face or abut a corresponding end surface of the handle assembly 12, thereby defining an axial stop surface thatP-WO-TN-2025-0009 / / 1076-0022WO Patent limits insertion depth and / or provides a load-bearing interface between the battery pack 500 and the power tool 10 during operation.[000212] In other embodiments, the transitional region 508 defines a sloped, tapered, radiused, curved, or smoothly blended surface rather than a discrete step. Such transitional surfaces may extend partially or entirely along the pack longitudinal axis 523 and provide a gradual change in exterior envelope between the first housing portion 504 and the second housing portion 506, such that the transition occurs over an axial distance rather than at a single axial plane.[000213] In some embodiments, the magnitude of the transverse change between the first housing portion 504 and the second housing portion 506 may be characterized by a difference T3 representing an incremental transverse offset between the tw o housing portions measured along a direction orthogonal to the pack longitudinal axis 523. In some configurations, the difference T3 is substantially uniform across multiple exterior sides of the pack housing 502. In other configurations, the difference T3 varies by location, such that the second housing portion 506 projects transversely beyond the first housing portion 504 by a greater amount in some regions than in others, while still maintaining a larger or substantially equal overall transverse envelope.[000214] In some embodiments, the transitional region 508 is axially non-uniform, such that a location, depth, or profile of the transition between the first housing portion 504 and the second housing portion 506 varies along different exterior sides of the pack housing 502. As a result, the transition may occur at different axial positions along different portions of the pack housing 502. Such axial variation may complement contoured, angled, or sculpted interface geometries of the handle assembly 12.[000215] In embodiments in which the transitional region 508 is not uniform along the length of the pack housing 502, the boundary between the first housing portion 504 and the second housing portion 506 need not correspond to a single, discrete planar interface. Instead, the first housing portion 504 and the second housing portion 506 may be defined functionally and volumetrically, rather than solely by a specific geometric edge or step.[000216] In such embodiments, the first housing portion 504 generally corresponds to the portion of the pack housing 502 that is configured to be received within the battery receptacle cavity of the handle assembly 12 of the power tool 10, while the second housing portion 506 generally corresponds to the portion of the pack housing 502 that is configured to remain exposed and form an external, user-engageable grip section when the battery pack 500 is installed. The transitional region 508 may extend across different positions along the exterior of the pack housing 502 such that portions of the housing gradually transition between these two functional regions.[000217] For example, along a first exterior side of the pack housing 502. the first housing portion 504 may extend farther toward the lower end 522 before transitioning to the second housing portion 506, while along another exterior side, the transition may occur closer to the upper end 520. In such cases, the first housing portion 504 may be understood as encompassing all regions of the housing configured for insertion and retention within the handle assembly 12, even if those regions terminate at different locations along the length of the pack housing 502. Similarly, the second housing portion 506 may be understood as encompassing all regions of the housingP-WO-TN-2025-0009 / / 1076-0022WO Patent configured to define the external grip section, even if those regions begin at different locations along the length of the pack housing 502.[000218] The second housing portion 506 includes an exterior surface defining a grip surface 512 of the battery pack 500. The grip surface 512 may extend over at least a portion of the second housing portion 506 and may include contoured regions, surface textures, ribs, material variations, or combinations thereof configured to facilitate manual gripping and handling of the battery pack 500 during installation, removal, or operation of the power tool 10. In some embodiments, the exterior geometry7of the second housing portion 506 includes contoured regions positioned to engage specific anatomical regions of a user’s hand, including regions configured to support a thenar region, a hypothenar region, or a proximal palmar region.[000219] At the lower end 522 of the pack housing 502, the battery pack 500 includes a lower base portion 525 that may define a transverse envelope greater than that of the second housing portion 506. The lower base portion 525 may provide structural reinforcement, accommodate internal components, improve stability when the batten7pack 500 is placed on a support surface, or support one or more user-interface features 518. In some embodiments, the lower base portion 525 is integrally formed with the pack housing 502. In other embodiments, the lower base portion 525 is formed as a separate housing component coupled to the pack housing 502.[000220] The user-interface features 518 supported by the pack housing 502 may include, but are not limited to, battery status indicators, charge-level indicators, state-of-charge indicators, light-emitting elements, buttons, or combinations thereof. In some embodiments, the user-interface features 518 are positioned on multiple exterior sides of the lower base portion 525 such that the user-interface features 518 are visible from different viewing directions when the battery pack 500 is installed on the power tool 10 or when removed. The battery7pack 500 can include at least one user-actuatable button 571 supported by the lower base portion 525. The user-actuatable button 571 may be operable to selectively activate the user-interface features 518 and / or to actuate a retention mechanism for releasing the battery7pack 500 from the power tool 10, and the userinterface features 518 are configured to provide visual and / or tactile information to a user regarding a state of charge, operating condition, functionality, or other status of the battery pack 500.[000221] In some embodiments, the battery pack 500 includes a retention interface 544 positioned along the first housing portion 504 adjacent the upper end 520 of the pack housing 502. The retention interface 544 is configured to cooperate with a complementary retention feature of the handle assembly 12 of the power tool 10 to resist unintended withdrawal of the battery pack 500 when installed, while permitting intentional removal by a user.[000222] In some embodiments, the retention interface 544 includes a user-actuatable release member supported on an exterior portion of the pack housing 502. The retention interface 544 is operatively coupled to an internal retention element configured to be received within, engage, or bias against a corresponding recess, groove, shoulder, or retention feature formed within the handle assembly 12 when the battery pack 500 is seated along the pack longitudinal axis 523.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000223] The retention interface 544 may be implemented as a hog ring, spring ring, resilient ring, split ring, or other elastically deformable retention member. In such embodiments, the retention interface 544 is configured to deflect during insertion of the battery pack 500 into the handle assembly 12 and to expand or seat into a corresponding engagement feature of the handle assembly 12 once the battery pack 500 reaches an installed position. This engagement can provide axial retention, tactile feedback to the user, and / or resistance to vibration-induced loosening during operation.[000224] In some embodiments, the retention interface 544 may be non-circular, segmented, discontinuous, or localized to one or more exterior regions of the first housing portion 504. For example, the retention interface 544 may include one or more resilient tabs, arcuate segments, protrusions, detents, or spring-biased elements arranged to engage the handle assembly 12 at discrete locations.[000225] In some embodiments, the retention interface 544 cooperates with the user-actuatable button 571 and an internal release mechanism such that actuation of the user-actuatable button 571 selectively disengages the retention interface 544 from the handle assembly 12, thereby permitting controlled removal of the battery pack 500. In other embodiments, the retention interface 544 provides passive retention and removal is accomplished by applying a predetermined axial withdrawal force. In this manner, the retention interface 544 provides a robust mechanical coupling between the battery pack 500 and the handle assembly 12 and supports repeated insertion and removal cycles.[000226] Referring to FIG. 6E, the battery' pack 500 includes a set of battery' pack electrical terminals 526 positioned at an upper end 520 of the pack housing 502, which defines a tool-facing end of the battery pack 500. The upper end 520 is configured to be received within a battery' receptacle cavity' of a power tool 10 along an insertion direction substantially parallel to the insertion axis 521, and the battery pack electrical terminals 526 are arranged to electrically couple with corresponding tool-side terminals as the battery' pack 500 is seated within the battery receptacle cavity.[000227] The battery pack electrical terminals 526 include at least a battery pack positive power terminal 528 and a battery pack negative power terminal 529 and may further include additional terminals 530 such as, but not limited to, temperature-sense terminals, intermediate-voltage sense terminals, communication terminals, identification terminals, auxiliary’ power terminals, or control terminals. As described herein, in some embodiments, one or more of the battery pack electrical terminals 526 are positioned within interstitial regions defined between adjacent battery cells housed within the pack housing 502, thereby permitting a compact terminal layout while facilitating direct electrical engagement with corresponding tool-side terminals of the power tool 10.[000228] In some embodiments, the battery' pack electrical terminals 526 are formed as solid conductive members. In some embodiments, the battery' pack electrical terminals 526 have a terminal diameter of about 5 mm and a conductive cross-sectional area of about 20 square mm. In some embodiments, an axial engagement length between the battery' pack electrical terminals 526P-WO-TN-2025-0009 / / 1076-0022WO Patent and corresponding tool-side terminals is about 20 mm when the battery pack 500 is installed in the power tool 10. In some embodiments, the axial engagement length is less than about 20 mm.[000229] When the battery pack 500 is installed in the power tool 10, the battery pack electrical terminals 526 positioned at the upper end 520 may be located adjacent internal control components, switching elements, or motor power terminals of the power tool 10. In some embodiments, one or more of the battery pack electrical terminals 526 are positioned at a distance of about 20 mm from a circuit board, switch assembly, or motor power terminal of the power tool 10 when the battery pack 500 is fully installed. In some embodiments, the distance between the battery pack electrical terminals 526 and such components is less than about 20 mm. Electrical coupling between the battery pack 500 and the power tool 10 may be provided through rigid electrical connectors supported by a circuit board within the handle assembly 12.[000230] Similarly, the second housing portion 506 may define an axially non-uniform profile, such that an upper boundary, lower boundary, or both vary in axial position about the insertion axis 521. In some embodiments, the axial variation of the second housing portion 506 corresponds to, complements, or continues the axial variation of the first housing portion 504, thereby defining a continuous or coordinated exterior profile. In some embodiments, such axially non-uniform profiles are provided to align with or complement a contoured geometry of a handle housing of the power tool 10, including angled, stepped, or sculpted interface surfaces.[000231] In some cases, the transitional region 508 may be shaped to complement a corresponding contour or profile of the handle housing of the power tool 10. By way of nonlimiting example, a first circumferential portion 511 of the transitional region 508 may be positioned at a relatively higher axial location along the insertion axis 521, while a second circumferential portion 513 of the transitional region 508 is positioned at a relatively lower axial location, thereby matching an angled, contoured, or sculpted interface region of the handle housing. This complementary geometry may improve ergonomic continuity, structural engagement, or load distribution when the battery pack 500 is installed.[000232] In some embodiments, the second transverse dimension T2 of the second housing portion 506 is greater than the first transverse dimension T1 of the first housing portion 504 at each circumferential location about the insertion axis 521, such that the second housing portion 506 defines a transverse envelope that is larger than that of the first housing portion 504 around the perimeter of the pack housing 502. In some embodiments, the magnitude of the difference T3 between the first transverse dimension T1 and the second transverse dimension T2 is substantially uniform about the perimeter of the pack housing 502. In some embodiments, the magnitude of the difference T3 varies circumferentially about the insertion axis 521 while the second transverse dimension T2 remains greater than or equal to the first transverse dimension T1 in all circumferential directions.[000233] In some embodiments in which the difference T3 varies circumferentially, the second housing portion 506 may extend transversely beyond the first housing portion 504 by a relatively greater amount in one or more circumferential regions and by a relatively lesser amount in one or more other circumferential regions, while maintaining a transverse envelope that exceeds that ofP-WO-TN-2025-0009 / / 1076-0022WO Patent the first housing portion 504 at each circumferential location. Such configurations permit non-uniform, asymmetric, contoured, or ergonomically sculpted exterior profiles of the second housing portion 506 while preserving the distinction between the insertable section defined by the first housing portion 504 and the external grip section defined by the second housing portion 506.[000234] The second housing portion 506 includes an exterior surface defining a grip surface 512 of the batter}' pack 500. The grip surface 512 may form at least a portion of the external grip section of the battery pack 500 and extend circumferentially around at least a portion of the pack housing 502, including partially or entirely about the perimeter of the second housing portion 506. In some embodiments, the grip surface 512 includes one or more contoured regions, ribs, textures, surface finishes, or combinations thereof configured to facilitate manual gripping and handling of the battery pack 500 during installation, removal, or operation of the power tool 10.[000235] When the battery pack 500 is installed in the power tool 10, such as the power tool 10 of FIG. 1, the grip surface 512 of the second housing portion 506 may be positioned adjacent to a grip surface of the handle housing such that the battery pack 500 and the handle housing collectively define a continuous grip surface extending along a handle axis of the power tool 10. In some such cases, the battery pack 500 may define at least a portion of a user-engageable portion of the handle and is configured to support gripping and reaction forces applied by a user during operation of the power tool 10. thereby functioning as a structural and ergonomic extension of the handle rather than solely as a removable electrical power source.[000236] In some embodiments, the exterior geometry of the second housing portion 506 includes contoured regions configured to engage specific anatomical regions of a user’s hand during operation. For example, the pack housing 502 may include recessed, convex, or angled surface regions positioned to support a thenar region, a hypothenar region, or a proximal palmar region of a user’s hand.[000237] The pack housing 502 can include a lower base portion 525 positioned at or adjacent the lower end 522 of the pack housing 502. The lower base portion 525 may have a transverse envelope that is greater than the transverse envelope of the second housing portion 506. The lower base portion 525 may serve one or more functions, including, but not limited to, providing structural reinforcement, accommodating internal components, improving stability when the battery pack 500 is placed on a support surface, and / or housing user-interface or electrical features.[000238] In some embodiments, the lower base portion 525 defines a widened region relative to the second housing portion 506 such that the battery’ pack 500 has a stepped or flared profile in a lower region thereof. The lower base portion 525 may be integrally formed with the pack housing 502 or may be formed as a separate housing component coupled to the pack housing 502. The presence of the lower base portion 525 may not alter the function of the second housing portion 506 as an external grip section. In some cases, the lower base portion 525 may be considered a part of the second housing portion 506.[000239] In the illustrated embodiments of FIGS. 5A-5C, the user-interface features 518 are positioned along the lower base portion 525 of the pack housing 502 at a plurality of circumferential locations. In some embodiments, the user-interface features 518 are provided onP-WO-TN-2025-0009 / / 1076-0022WO Patent opposite sides of the lower base portion 525 such that the user-interface features 518 are visible from multiple viewing directions about the insertion axis 521. This arrangement may allow the user-interface features 518 to be readily visible to a user both when the battery pack 500 is installed on a power tool 10 and when the battery pack 500 is removed from the power tool 10. The placement of the user-interface features 518 on the lower base portion 525 can allow charge-status or other information to be communicated to the user without interfering with the grip surface defined by the second housing portion 506 and without requiring a particular orientation of the battery pack 500 for viewing.[000240] The battery pack electrical terminals 526 include at least a battery pack positive power terminal and a battery pack negative power terminal. In some embodiments, the battery pack electrical terminals 526 further include one or more additional terminals, such as, but not limited to, a temperature-sense terminal, an intermediate-voltage sense terminal, or other control or communication terminals. As described in more detail herein, in some embodiments, individual battery pack electrical terminals 526 are positioned within interstitial spaces between adjacent battery cells within the batten- pack 500, such that the battery pack electrical terminals 526 are supported at the upper end 520 of the pack housing 502 in a compact arrangement. The interstitial spaces may be sized, shaped, and oriented to receive corresponding terminal projections, blades, pins, or contacts of the power tool 10 when the battery pack 500 is installed, thereby permitting direct electrical engagement between tool-side terminals and the battery’ pack electrical terminals 526.[000241] When the battery pack 500 is installed in a power tool 10, the battery' pack electrical terminals 526 located at the upper end 520 can be positioned adjacent internal electrical and control components of the power tool 10. In some embodiments, the battery pack electrical terminals 526 are positioned adjacent a trigger switch, a switch assembly, motor power terminals, or combinations thereof. In this installed configuration, electrical coupling between the battery pack 500 and the power tool 10 occurs over a relatively’ short electrical path length.[000242] In some embodiments, when the battery pack 500 is fully installed in the pow’er tool 10, the battery’ pack electrical terminals 526 at the upper end 520 are positioned within approximately 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 40 mm, or 50 mm of a closest portion of at least one of a trigger switch, a switch assembly, or motor power terminals of the power tool 10. In some embodiments, the battery pack electrical terminals 526 are positioned within a distance ranging from approximately 10 mm to approximately 30 mm of one, some, or all such components.[000243] In certain embodiments, electrical coupling between the battery pack electrical terminals 526, the trigger switch, the switch assembly, and the motor power terminals is provided through a common circuit board supported within the handle housing of the power tool 10. In some such configurations, the electrical coupling may be provided exclusively by rigid electrical connectors mounted to the circuit board.[000244] In some embodiments, the battery pack electrical terminals 526 are positioned at the upper end 520 of the elongate pack housing 502 such that, when the battery pack 500 is receivedP-WO-TN-2025-0009 / / 1076-0022WO Patent within a handle housing of a power tool 10. electrical engagement between the batten' pack 500 and the power tool 10 occurs at a location adjacent internal control and switching components of the power tool 10. In such embodiments, the battery pack 500 occupies a portion of the handle volume while maintaining electrical coupling at an upper region of the handle housing.[000245] In the illustrated embodiments, the first housing portion 504 and the second housing portion 506 of the pack housing 502 each have a generally oval cross-section when viewed in a plane perpendicular to the insertion axis 521. In such embodiments, each housing portion includes a major transverse dimension and a minor transverse dimension measured orthogonally to one another, such that the transverse extent of the housing portions varies circumferentially about the insertion axis 521. It will be appreciated that other cross-sectional shapes may be used, including but not limited to rounded-rectangular, racetrack-shaped, lobed, faceted, asymmetric, or compound profiles. In some such configurations, the transverse dimensions T1 and T2 may vary continuously or discontinuously about the perimeter of the pack housing 502. In some cases, regardless of the cross-sectional shape employed, the first housing portion 504 remains configured for insertion into a corresponding battery receptacle cavity of a power tool 10, and the second housing portion 506 remains configured to define an external, user-engageable grip surface when the battery pack 500 is installed.[000246] The lower end 522 of the pack housing 502 includes a lower base portion 525 forming a bottom-facing region of the battery pack 500. In the illustrated embodiment, the lower base portion 525 includes a rear cover secured to the pack housing 502 by a plurality of fasteners 592, the fasteners permitting assembly, disassembly, or servicing of internal components of the battery pack 500.[000247] FIGS. 7A and 7B illustrate partially exploded views of the battery pack 500 of FIGS.6A-6F. FIG. 7A illustrates a partially exploded isometric view from a lower-end orientation of the battery pack 500, and FIG. 7B illustrates a partially exploded isometric view from an upper-end orientation of the battery pack 500. In each view, internal components of the battery pack 500 are shown separated from the pack housing 502 generally along the pack longitudinal axis 523.[000248] The battery pack 500 includes a battery assembly 740 configured to be received within the pack housing 502. When assembled, the batten’ assembly 740 extends generally along the pack longitudinal axis 523 and is supported within interior volumes defined by the first housing portion 504 and the second housing portion 506 of the pack housing 502.[000249] The battery assembly 740 includes a first cell group 741 and a second cell group 742 that are positioned at different locations along the length of the battery pack 500 / the pack longitudinal axis 523. In the illustrated embodiment, the first cell group 741 is positioned near the upper end 520 of the pack housing 502, while the second cell group 742 is positioned below the first cell group 741, closer to the lower end 522 of the pack housing 502. In this arrangement, the first cell group 741 and the second cell group 742 occupy separate regions of the pack housing 502 and are arranged in a stacked-along-the-length configuration, rather than being located within the same cross-section or grouped together side-by-side.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000250] Each of the first cell group 741 and the second cell group 742 includes one or more battery cells 745. In the illustrated embodiment of FIGS. 7A and 7B, the individual battery cells 745 are labeled for reference as cell 1, cell 2. cell 3, cell 4, and cell 5. In this example, the first cell group 741 includes two batter}’ cells: cell 1 and cell 5, which are positioned nearer the upper end 520 of the pack housing 502, and the second cell group 742 includes three battery cells: cell 2, cell 3, and cell 4, which are positioned below the first cell group 741 toward the lower end 522 of the pack housing 502. It will be appreciated that this identification is illustrative, and that different reference numbers for the battery cells 745 may be assigned to the first cell group 741 and the second cell group 742 in other embodiments.[000251] In the illustrated embodiment, each battery' cell 745 is elongate and extends generally parallel to the pack longitudinal axis 523. In some embodiments, the battery cells 745 within a given cell group are oriented generally parallel to one another, and selected battery cells within different cell groups may be colinear with one another along a common longitudinal reference axis. In other embodiments, one or more of the battery' cells 745 has a longitudinal axis that is offset relative to another battery cell 745 within the same cell group, within a different cell group, and / or relative to the pack longitudinal axis 523 by up to approximately -10 degrees to +10 degrees, while remaining generally aligned along the length of the battery pack 500.[000252] When the battery pack 500 is assembled, the first cell group 741 is generally positioned within a volume defined by the first housing portion 504 of the pack housing 502, and the second cell group 742 is generally positioned within a volume defined by the second housing portion 506 of the pack housing 502. In this arrangement, at least a portion of one or more battery cells 745 of the first cell group 741 is received within a battery’ receptacle cavity of the power tool 10 and is located within the handle assembly 12 when the battery pack 500 is installed.[000253] By contrast, at least a portion of one or more battery cells 745 of the second cell group 742 remains outside the battery receptacle cavity and is supported within an external grip section defined by the pack housing 502. For example, in some embodiments, the entirety of the first cell group 741 is positioned within the handle assembly 12 of the power tool 10, while the second cell group 742 is positioned entirely below the handle assembly 12. In other embodiments, the first cell group 741 partially overlaps the handle assembly 12, and the second cell group 742 partially overlaps the handle assembly 12 while still extending outward to define the external grip section. In still other embodiments, one or more battery cells 745 of the second cell group 742 extend predominantly or entirely within the external grip section while maintaining electrical connection with battery’ cells of the first cell group 741.[000254] FIGS. 8 A and 8B illustrate partially exploded isometric views of the battery pack 500, with portions of the pack housing 502 removed or omitted for clarity. In particular, FIGS. 8A and 8B show internal components positioned adjacent a lower end 522 of the battery’ pack 500, including portions of the battery assembly 740 and associated lower-end interface and electronics components. FIG. 8A illustrates a partially exploded isometric view from an upper-end orientation, and FIG. 8B illustrates a partially exploded isometric view from a lower-end orientation.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000255] As shown in FIGS. 8A and 8B, the battery pack 500 includes the battery assembly 740 and a lower-end electronics subassembly 848 positioned at or near the lower end 522 of the battery pack 500. These components may include one or more end caps, interface plates, retention features, or support members that cooperate with the battery assembly 740 and the pack housing 502 when assembled.[000256] In the illustrated embodiments, one or more light-transmitting elements 847 are positioned adjacent the lower end region of the batten' pack 500. The light-transmitting elements 847 are configured to convey light from one or more light-emitting components to exterior regions of the pack housing 502 when the battery pack 500 is assembled. The light-transmitting elements 847 may include light pipes, lenses, windows, or other optical transmission structures, and may extend through or align with openings, recesses, or translucent regions of the pack housing 502.[000257] The light-transmitting elements 847 may be positioned adjacent a PCB 546 and may be retained relative to the battery pack 500 by one or more fasteners, clips, adhesive interfaces, or cooperative housing features. In some embodiments, the light-transmitting elements 847 are coupled to a lower-end interface structure that also supports user-interface features, such as indicator windows or button features, as described further below.[000258] FIGS. 9 A and 9B illustrate perspective views of a lower-end electronics subassembly 848 of the batten’ pack 500. FIG. 9A illustrates the lower-end electronics subassembly 848 in an assembled configuration, and FIG. 9B illustrates a partially exploded view in which one or more light-transmitting elements 847 are shown separated from adjacent components for clarity. As shown, the lower-end electronics subassembly 848 includes a PCB 546 positioned adjacent the lower end 522 of the battery pack 500.[000259] In some embodiments, the pack housing 502 is formed from multiple housing portions that meet along a housing parting line located adjacent the lower end 522 of the battery' pack 500. In such embodiments, the PCB 546 is positioned within the housing 502 adjacent the housing parting line and at an axial end of the battery pack 500 opposite battery pack electrical terminals supported at an upper end of the housing.[000260] In some embodiments, a single light-emitting component 599 mounted on the PCB 546 is configured to emit light through more than one externally visible light opening of the housing 502. In some embodiments, the housing 502 defines light openings on opposing sides of the battery pack 500, and one or more light-transmitting elements 847 are configured to direct light from the light-emitting component 599 to the opposing sides of the housing such that the emitted light is visible from multiple directions.[000261] The PCB 546 may support one or more electronic components associated with battery' monitoring, control, protection, communication, and or user-interface functionality. By way of non-limiting example, the PCB 546 may support circuitry for monitoring battery’ pack and or battery' cell voltage, current, temperature, state of charge, or state of health, as well as control or protection circuitry' configured to manage charging and discharging of the battery' cells 745.[000262] In some embodiments, the battery pack 500 includes one or more user-interface features 518 supported at the lower end 522 of the pack housing 502. The user-interface featuresP-WO-TN-2025-0009 / / 1076-0022WO Patent 518 may include one or more light-emiting components 599, one or more light-transmitting elements 847, one or more user-actuatable buttons 571, or combinations thereof.[000263] In some embodiments, the PCB 546 supports one or more light-emiting components 599 corresponding to the user-interface features 518, such as charge-level indicators, status indicators, or warning indicators. Light emited by the light-emiting components 599 may be transmited to exterior regions of the batery pack 500 through one or more light-transmiting elements 847 that are aligned with openings, recesses, or translucent regions of the pack housing 502, as illustrated in FIGS. 9A and 9B.[000264] In some embodiments, the PCB 546 supports or is electrically coupled to one or more user-actuatable butons 571 positioned at the lower end 522 of the batery pack 500. The user-actuatable button 571 may form part of the user-interface features 518 and may be operable to selectively activate one or more visual indicators, initiate a battery status display sequence, and or actuate a retention or release mechanism that permits removal of the bater}' pack 500 from the power tool 10.[000265] When the batery pack 500 is fully assembled, the lower-end electronics subassembly 848 cooperates with the pack housing 502, the batery assembly 740, and the user-interface features 518. including in some embodiments the light-emiting components 599, the lighttransmiting elements 847. and or the user-actuatable buton 571, to provide a compact, robust, and user-accessible interface that supports electrical functionality, visual indication, and mechanical interaction while maintaining the ergonomic and structural characteristics of the batery pack 500.[000266] FIGS. 10A, 10B, 10C, 10D, 10E, and 10F illustrate various views of the batery' assembly 740 of the batery pack 500. The views of FIGS. 10A-10F illustrate example internal structures, batery' cell arrangements, and relative positioning of batery' cells 745 within the batery' assembly 740. FIG. 10A illustrates an isometric view of the batery assembly 740 from a first end, and FIG. 10B illustrates an isometric view of the batery assembly 740 from an opposite end. FIGS.10C-10F illustrate four different side views of the batery' assembly 740 taken from different angular orientations about the pack longitudinal axis 523.[000267] The batery assembly 740 includes an internal support and electrical interconnection structure 1050 configured to support, position, and electrically interconnect a plurality of batery cells 745. The internal support and electrical interconnection structure 1050 defines cell-receiving regions that locate the batery cells 745 in predetermined spatial relationships relative to one another while maintaining the batery cells 745 generally aligned along the pack longitudinal axis 523.[000268] In some embodiments, the internal support and electrical interconnection structure 1050 defines distinct cell-receiving regions corresponding to the first cell group 741 and the second cell group 742 positioned at different locations along the length of the batery' assembly 740 / the pack longitudinal axis 523. The internal support and electrical interconnection structure 1050 may include internal walls, partitioning ribs, support surfaces, retention features, insulating features, orP-WO-TN-2025-0009 / / 1076-0022WO Patent combinations thereof configured to separate adjacent battery cells 745, maintain spacing between battery cells 745. and provide structural rigidity to the battery assembly 740.[000269] As shown in FIGS. 10A-10F. the battery assembly 740 includes five battery cells 745, identified for reference as cell 1, cell 2, cell 3, cell 4. and cell 5. The battery cells 745 are arranged into the first cell group 741 and the second cell group 742 that occupy different longitudinal regions of the battery' assembly 740 rather than being arranged together within a single common cross-section. In the illustrated embodiment, the first cell group 741 includes two battery' cells 745, labeled cell 1 and cell 5, and the second cell group 742 includes three battery' cells 745, labeled cell 2, cell 3, and cell 4. The first cell group 741 and the second cell group 742 are positioned sequentially along the length of the battery' assembly 740 / the pack longitudinal axis 523.[000270] Each battery cell 745 is elongate and extends generally' parallel to the pack longitudinal axis 523. The relative positions of the battery cells 745 within the first cell group 741 and the second cell group 742 are illustrated to demonstrate example spatial relationships between battery cells located in different regions of the battery assembly 740.[000271] The views of FIGS. 10A-10F are illustrative and non-limiting and are provided to demonstrate example arrangements of the battery cells 745 within the battery assembly 740.[000272] FIG. 11 illustrates an isolated view of the electrical interconnection members 1120 without the battery cells 745 or the internal support and electrical interconnection structure 1050. In this view, the electrical interconnection members 1120 are shown in spatial positions corresponding to their installed locations relative to the battery cells 745 when assembled. FIG. 11 illustrates the routing, shape, and relative positioning of the electrical interconnection members 1120 independent of the battery' cells, thereby highlighting the electrical topology and interconnection strategy employed within the battery' pack 500.[000273] In the illustrated embodiment, the electrical interconnection members 1120 are configured to electrically couple the battery cells 745 in a single series electrical circuit. The electrical interconnection members 1120 may be formed from electrically conductive material, such as, but not limited to, nickel, nickel-plated steel, copper, copper alloy, or other suitable conductive metals, and may be provided as stamped conductors, bent conductors, welded conductors, bus bars, or combinations thereof.[000274] The electrical interconnection members 1120 may include a plurality of discrete conductive members, such as a first electrical interconnection member 1120A, a second electrical interconnection member 1120B, a third electrical interconnection member 1120C, a fourth electrical interconnection member 1120D, a fifth electrical interconnection member 1120E, and a sixth electrical interconnection member 1120F (individually or collectively referred to as “electrical interconnection member 1120” or “electrical interconnection members 1120”). Each of the electrical interconnection members 1120 may be configured to electrically couple one or more battery-cell terminals and / or one or more pack terminals when the battery' cells 745 are installed, such that the electrical interconnection members 1120 collectively establish a continuous series electrical path through the plurality of battery cells 745 between a pack negative node and a pack positive node.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000275] In the illustrated embodiment, one or more of the electrical interconnection members 1120 define terminal conductors corresponding to ends of a series electrical circuit, while one or more other electrical interconnection members 1120 define intermediate cell-to-cell electrical connections within the series electrical circuit. For example, the first electrical interconnection member 1120 A and the sixth electrical interconnection member 1120F may correspond to terminal conductors associated with a pack negative node and a pack positive node, respectively, while the remaining electrical interconnection members 1120B, 1120C, 1120D, 1120E electrically couple adjacent battery cells within the battery' pack 500.[000276] As illustrated in FIG. 11, the second electrical interconnection member 1120B includes a generally U-shaped conductive form configured to electrically couple end terminals of two battery cells that are generally longitudinally aligned with one another. The third electrical interconnection member 1120C includes a generally planar conductive form configured to electrically couple end terminals of adjacent battery cells positioned beside one another (radially offset from each other). The fourth electrical interconnection member 1120D includes an elongated conductive portion configured to electrically couple battery cells positioned side-by-side (radially offset from each other) while connecting terminals located at opposite axial ends of those battery cells. The fourth electrical interconnection member 1120D extends generally along a lengthwise direction of the battery assembly 740 and transitions laterally to electrically connect a terminal at one axial end of a first battery cell with a terminal at an opposite axial end of an adj acent battery’ cell. In this manner, the fourth electrical interconnection member 1120D provides a cross-cell electrical connection between laterally adjacent battery cells. The fifth electrical interconnection member 1120E includes a bent or stepped conductive form configured to electrically connect a battery cell of the first cell group 741 yvith a battery- cell of the second cell group 742 (both axially and radially offset from each other).[000277] In some embodiments, one or more of the electrical interconnection members 1120 may be omitted or modified. For example, in some embodiments, the second electrical interconnection member 1120B may be omitted where adjacent battery cells are positioned in direct terminal -to-terminal contact, such that electrical coupling between the adjacent battery cells is achieved without an intervening conductive member. The number, shape, and configuration of the electrical interconnection members 1120 may be varied yvithout departing from the scope of the present disclosure.[000278] In some embodiments, the electrical interconnection architecture of the battery pack 500 is configured to establish a single series electrical circuit through the plurality of battery cells 745 while controlling and minimizing the total conductive length of the electrical interconnection members 1120. As used herein, the total conductive length refers to the cumulative length of all electrically conductive material forming the series electrical path between a first terminal node (i.e., electrical interconnection member 1120A) and a second terminal node (i.e., electrical interconnection member 1120F) of the battery pack 500, including conductive segments extending between weld locations, bends, offsets, transitions, and terminal interfaces.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000279] In the illustrated embodiment, the electrical interconnection members 1120 are arranged such that a majority of the electrical connections between adjacent battery cells 745 are formed at end-terminal regions of the battery cells. In this configuration, electrical coupling is achieved primarily at end faces of the battery cells, rather than by routing conductors along the side surfaces of the battery cells over extended distances. By concentrating electrical interconnections at end-terminal regions, the architecture reduces the amount of conductive material required to traverse between cells located at different positions within the battery' assembly 740.[000280] In some embodiments, the electrical interconnection architecture is configured such that no more than one electrical interconnection member extends generally parallel to a longitudinal axis of a battery- cell 745 along a side surface thereof. In the illustrated embodiment, a single electrical interconnection member (i.e., electrical interconnection member 1120D) extends between opposite end faces of a set of battery cells, such that it crosses a longitudinal axis of at least one battery cell 745. All remaining electrical interconnection members 1120A, 1120B, 1120C, and 1120E are confined to end-terminal regions and do not extend longitudinally along the side surface of a battery cell.[000281] Limiting the number of electrical interconnection members that extend along side surfaces of battery cells reduces the cumulative conductive path length required to electrically couple the battery’ cells in series. In some embodiments, a total conductive length of all electrical interconnection members within the battery pack 500, measured as the sum of linear lengths of electrically conductive material forming the series electrical path between adjacent battery-cell terminals, including bends, offsets, and transitions between terminal regions, is less than approximately 120 mm, less than approximately 100 mm, less than approximately 80 mm, or less than approximately 60 mm. These values reflect an architecture in yvhich electrical connections are short, direct, and localized to terminal regions of the battery cells, rather than distributed along extended sidewall surfaces or routed across the internal volume of the battery' pack.[000282] In some embodiments, the battery' pack includes a plurality of electrical interconnection members 1120 configured to electrically couple adjacent battery cells in series. Each electrical interconnection member 1120 includes one or more welded electrical junctions formed at end terminals of battery cells and a conductive portion extending between those welded electrical junctions. As used herein, an individual interconnection weld span refers to a length of electrically conductive material extending between two welded electrical junctions associated yvith a single electrical interconnection member 1120. In some embodiments, an individual interconnection weld span is approximately 4.4 mm. In some embodiments, an individual interconnection weld span is less than about 5 mm. In some embodiments, individual interconnection weld spans vary' among different electrical interconnection members and may fall within a range of approximately 4.1 mm to approximately 7.5 mm.[000283] In some embodiments, the electrical interconnection members 1120 collectively define a single series electrical path through the battery pack 500. As used herein, a total series interconnection length refers to a cumulative length of electrically conductive material formingP-WO-TN-2025-0009 / / 1076-0022WO Patent the series electrical path between a first terminal node (node NNO) and a second terminal node (node NN5), excluding portions of terminal conductors that extend beyond welded electrical junctions for external electrical engagement. In some embodiments employing five battery cells connected in series, the total series interconnection length corresponds to the sum of four intermediate interconnection weld spans between adjacent battery cells. In some embodiments, the total series interconnection length is approximately 87.6 mm. In some embodiments, the total series interconnection length is less than about 90 mm. In some embodiments, the total series interconnection length is within a range of approximately 80 mm to approximately 110 mm.[000284] In some embodiments, an average interconnection spacing corresponds to an average distance between successive welded electrical junctions associated with adjacent battery cells along the series electrical path, excluding terminal conductors at the ends of the series circuit. In embodiments employing five battery cells connected in series, the average interconnection spacing is calculated across four intermediate interconnection weld spans. In some embodiments, the average interconnection spacing is approximately 21.9 mm. In some embodiments, the average interconnection spacing is less than about 25 mm. In some embodiments, the average interconnection spacing is within a range of approximately 18 mm to approximately 30 mm.[000285] In some embodiments, the electrical interconnection architecture is further characterized by a weld-to-weld average deviation, which corresponds to variation in spacing between successive welded electrical junctions formed by the electrical interconnection members 1120. In some embodiments, the weld-to-weld average deviation is 26.55 mm. In some embodiments, the weld-to-weld average deviation is less than about 27 mm. In some embodiments, the weld-to-weld average deviation is within a range of 20 to 30 mm.[000286] In some embodiments, the electrical interconnection members 1120 are further characterized by a controlled volume of conductive material forming the welded electrical junctions and the conductive portions extending between adjacent battery cells. In some embodiments, a total conductive volume of the electrical interconnection members 1120 is 0.519 cubic centimeters. In some embodiments, the total conductive volume is less than about 0.6 cubic centimeter. In some embodiments, the total conductive volume is within a range of 0.450 to 1.000 cubic centimeters.[000287] In some embodiments, the electrical interconnection members 1120 are further characterized by a controlled mass of conductive material forming the welded electrical junctions and the conductive portions extending between adjacent battery’ cells. In some embodiments, the total mass of conductive material forming the electrical interconnection members 1120 is 4.619 grams. In some embodiments, the total mass is less than about 5 grams. In some embodiments, the total mass is within a range of 4.005 to 8.900 grams.[000288] In some embodiments, the electrical interconnection architecture described herein facilitates a compact internal layout that balances electrical efficiency, manufacturability’, and mechanical robustness. By concentrating electrical connections near battery-cell end terminals, limiting side-extending conductors, and / or controlling total conductive length, the battery packP-WO-TN-2025-0009 / / 1076-0022WO Patent 500 achieves reduced resistive losses, simplified assembly, reduced conductor congestion, and / or improved repeatability of electrical connections.[000289] The electrical interconnection members 1120A-1120F collectively define a single series electrical path through the plurality of battery cells 745. Along this series electrical path, a plurality of electrically distinct connection points or nodes are defined, which may be referenced as node NO, node Nl, node N2, node N3, node N4, and node N5. Each node corresponds to a physical electrical junction between adjacent battery cells or between a battery7cell and a terminal structure of the battery7pack 500.[000290] In the illustrated embodiment, node NO corresponds to a first end of the series electrical circuit, and node N5 corresponds to a second end of the series electrical circuit. Nodes N1-N4 correspond to intermediate nodes located between adjacent battery cells connected in series. The node identifiers N0-N5 are used herein to describe relative positions along the series electrical path and do not denote fixed or absolute voltage values.[000291] In some embodiments, node NO corresponds to a battery pack negative node, and node N5 corresponds to a battery pack positive node. One or more of the intermediate nodes N1-N4 may correspond to intermediate electrical potentials within the series electrical circuit and may be used for sensing, monitoring, balancing, protection, or control functions of the battery pack 500.[000292] Because the battery cells 745 are electrically connected in series, the electrical potential at each successive node N1-N5 relative to node NO increases cumulatively as additional battery7cells are added in series. By way of non-limiting example, node N 1 may correspond to an electrical potential approximately equal to the voltage of a single battery cell relative to node NO, node N2 may correspond to an electrical potential approximately equal to the sum of two cell voltages, node N3 may correspond to an electrical potential approximately equal to the sum of three cell voltages, node N4 may correspond to an electrical potential approximately equal to the sum of four cell voltages, and node N5 may correspond to an electrical potential approximately equal to the sum of five cell voltages in embodiments employing five series-connected cells.[000293] The voltage contribution of each battery7cell may7vary depending on cell chemistry7, state of charge, temperature, or operating condition. Accordingly, the electrical potentials associated with nodes N1-N5 are described herein as approximate and illustrative rather than limiting.[000294] In some embodiments, one or more electrical terminals of the battery pack 500, such as an intermediate-voltage sense terminal, may be electrically coupled to one or more of the intermediate nodes N1-N4. Such intermediate-node connections may be used to provide battery¬ state information to monitoring or control circuitry7, including circuitry supported on the PCB 546 described herein.[000295] By way of non-limiting example, in embodiments using lithium-ion battery7cells having a nominal voltage of approximately 3.6 volts to approximately 3.7 volts per cell, node Nl may be approximately 3.6-3.7 volts relative to node NO, node N2 may be approximately 7.2-7.4 volts relative to node NO, node N3 may be approximately 10.8-11.1 volts relative to node NO, node N4 may be approximately 14.4-14.8 volts relative to node NO, and node N5 may be approximatelyP-WO-TN-2025-0009 / / 1076-0022WO Patent 18.0-18.5 volts relative to node NO. In embodiments using lithium-ion battery cells having a maximum charged voltage of approximately 4.2 volts per cell, node N1 may be approximately 4.2 volts, node N2 may be approximately 8.4 volts, node N3 may be approximately 12.6 volts, node N4 may be approximately 16.8 volts, and node N5 may be approximately 21.0 volts, each relative to node NO. In other embodiments, different cell chemistries, nominal voltages, maximum charged voltages, and series cell counts may be used, and the node voltages may vary accordingly.[000296] The node labeling described above is provided for clarity to illustrate cumulative series potentials and does not require a particular nominal voltage, maximum charged voltage, or chemistry. In some embodiments, one or more of the intermediate nodes N1-N4 may be used to provide intermediate-voltage sense signals for monitoring circuitry, and the electrical interconnection members 1120A-1120F may be configured to expose or define such intermediate nodes at predetermined locations within the battery pack 500.[000297] FIGS. 12A and 12B illustrate isolated views of the battery cells 745 and the electrical interconnection members 1120 of the battery assembly 740, with the pack housing 502 and the internal support and electrical interconnection structure 1050 omitted for clarity. These views are provided to illustrate representative physical placement of the electrical interconnection members 1120 relative to the battery cells 745 when assembled.[000298] Collectively, FIGS. 12A and 12B illustrates the positioning of battery cells 745, including cell 1, cell 3, cell 4, and cell 5. The electrical interconnection members 1120 are coupled to end-terminal regions of the battery cells 745 to establish a continuous series electrical path through the battery assembly 740, with intermediate node locations N0-N5 defined along the series electrical path. The illustrated node locations correspond to physical electrical junctions and are show n to clarify relative ordering along the series circuit.[000299] FIGS. 12A and 12B are illustrative and non-limiting and are provided to visually support previously described electrical interconnection architectures, including connections between battery cells 745 that are laterally adjacent, axially offset, and / or located in different longitudinal regions of the battery assembly 740.[000300] FIGS. 13A and 13B illustrate views of the internal support and electrical interconnection structure 1050 of the battery assembly 740, with the battery cells 745 and the pack housing 502 omitted for clarity. FIG. 13A illustrates an isometric view of the internal support and electrical interconnection structure 1050 from a first orientation, and FIG. 13B illustrates an isometric view from a second orientation.[000301] As shown in FIGS. 13A and 13B, the internal support and electrical interconnection structure 1050 is configured to support, locate, and electrically interconnect the battery' cells 745 of the battery assembly 740 when assembled. The internal support and electrical interconnection structure 1050 defines a plurality' of longitudinally extending cell-receiving regions, including a first cell-receiving region 1301 and a second cell-receiving region 1303, corresponding generally to the first cell group 741 and the second cell group 742 described herein.[000302] The internal support and electrical interconnection structure 1050 further defines internal surfaces, walls, and support features configured to position battery cells at predeterminedP-WO-TN-2025-0009 / / 1076-0022WO Patent locations relative to one another along the length of the battery assembly 740. In the illustrated embodiment, the cell-receiving regions 1301 and 1303 are arranged sequentially along the length of the batter}’ assembly 740 such that battery cells of the first and second cell groups occupy different longitudinal regions rather than being positioned within a single common cross-section.[000303] FIGS . 13 A and 13B further illustrate portions of the electrical interconnection members 1120 positioned relative to the internal support and electrical interconnection structure 1050. The electrical interconnection members 1120 are arranged to cooperate with end-terminal regions of the battery cells when installed, thereby defining a series electrical path through the battery’ assembly 740. Representative node locations N0-N5 are shown to indicate relative ordering of electrical junctions along the series circuit.[000304] As illustrated, the internal support and electrical interconnection structure 1050 may include alignment features 1325, retention features 1327, and conductor-receiving channels or passages 1326 configured to guide, support, or constrain the electrical interconnection members 1120. Such features facilitate controlled placement of conductive members, maintain electrical isolation between adjacent components, and support repeatable assembly of the battery' assembly 740.[000305] FIGS. 14A and 14B illustrate vieyvs of the battery assembly 740 showing representative placement of one or more battery’ pack terminals within the battery assembly 740 relative to adjacent battery’ cells arranged in a 2 + 3 configuration, in yvhich tyvo cells (cell 1 and cell 5) are positioned on a first side of the battery assembly and three cells (cell 2, cell 3, and cell 4) are positioned on an opposite side. The illustrated terminals may include, by way of example, a battery' pack positive power terminal 528, a battery pack negative po er terminal 529, a temperature-sense terminal 530, and an intermediate-voltage or signal terminals 531. FIG. 14A illustrates a view taken generally along the pack longitudinal axis 523 corresponding to a top view of the battery' assembly 740, and FIG. 14B illustrates a corresponding bottom view.[000306] As described herein, the battery assembly 740 includes a plurality of battery cells electrically connected in series. The illustrated arrangement is provided to demonstrate relative spatial relationships between battery cells and terminals and does not require a particular electrical configuration or voltage assignment.[000307] Referring to FIG. 14A, the illustrated view corresponds to a terminal-facing region of the battery assembly 740 adjacent cell 1 and cell 5. Dashed outlines 1454 and 1452 represent projected cylindrical envelopes of cell 1 and cell 5. respectively, corresponding to the full outer extents of those battery cells in the illustrated transverse plane. The dashed outlines are provided to illustrate geometric boundary conditions for terminal placement and do not require that the entirety of cell 1 or cell 5 be present at the illustrated plane.[000308] As shown, an interstitial geometry 1459 is defined between the dashed outlines 1454 and 1452 of cell 1 and cell 5. The interstitial geometry 1459 represents an interior volume between adjacent battery' cells that is available for component placement without increasing an overall transverse envelope of the battery assembly 740.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000309] One or more of the batery pack terminals, including the battery pack positive power terminal 528. the batery pack negative power terminal 529. and one or more additional terminals 530, are positioned at least partially within the interstitial geometry 1459 between the projected cylindrical envelopes of cell 1 and cell 5. The terminals are positioned such that they do not overlap, intrude into, or interfere with the projected cylindrical envelopes of cell 1 or cell 5, thereby avoiding contact with batery' cell housings while occupying otherwise unused interior volume of the batery' assembly 740.[000310] In the illustrated embodiment, the interstitial geometry 1459 is further bounded by tangent lines 1472 and 1474 extending between exterior surfaces of cell 1 and cell 5. In some embodiments, the batery pack positive and negative power terminals 528, 529 are positioned entirely' inward of the tangent lines 1472, 1474. In other embodiments, one or more portions of a batery pack positive or negative power terminal 528, 529 may' contact, coincide with, or extend slightly beyond a tangent line while remaining outside the projected cylindrical envelopes of the batery cells. For example, a batery pack positive or negative power terminal 528, 529 may be positioned such that a portion thereof lies within approximately 0-5 mm, 0-3 mm, or 0-1 mm of a tangent line defined between cell 1 and cell 5.[000311] In some embodiments, the batery’ pack positive and negative power terminals 528, 529 are centered within the interstitial geometry 1459. In other embodiments, the terminals are offset toward cell 1, offset toward cell 5, or asymmetrically positioned within the interstitial geometry’ depending on desired electrical engagement geometry , terminal block design, or mating features of a corresponding power tool. The illustrated arrangement is representative and non-limiting.[000312] By positioning the batery' pack positive and negative power terminals 528, 529 within the interstitial geometry' 1459 defined between the projected cylindrical envelopes of cell 1 and cell 5, the terminal structure occupies interior volume of the batery' pack 500 rather than projecting outward beyond an exterior envelope defined by the battery cells. This configuration allows corresponding tool-side terminals to extend into the interior of the battery pack 500 when the batery pack is seated within a batery receptacle cavity, thereby' reducing a required transverse envelope of the pack housing 502 and supporting reduced handle dimensions.[000313] Referring to FIG. 14B, the illustrated view corresponds to a botom view of the batery assembly 740 adjacent cell 2, cell 3, and cell 4. Dashed outlines 1462, 1464. and 1466 represent projected cylindrical envelopes of cell 2. cell 3, and cell 4, respectively.[000314] Additional dashed outlines 1430 and 1429 represent projected edges of the battery pack positive and negative power terminals 528. 529, respectively. The dashed outlines 1430, 1429 illustrate the transverse extent of the terminals as projected onto the plane of FIG. 14B, even though the terminals are positioned at a different longitudinal location within the batery' assembly 740 and are not physically located at the same longitudinal depth as cell 2, cell 3, or cell 4.[000315] In some embodiments, cell 2, cell 3, and cell 4 do not extend fully into the longitudinal region occupied by the batery' pack positive and negative pow er terminals 528, 529 show n in FIG.14A. Instead, one or more of cell 2, cell 3, or cell 4 may terminate axially short of the terminal region, may extend only partially' along longitudinal sides of cell 1 and cell 5, or may be separatedP-WO-TN-2025-0009 / / 1076-0022WO Patent from the terminal region by internal support structures. Accordingly, the dashed outlines 1462, 1464. and 1466 in FIG. 14B illustrate projected cell boundaries rather than direct terminal adjacency.[000316] As illustrated, the projected outlines 1430. 1429 of the batten’ pack positive and negative power terminals 528. 529 do not align with, intrude into, or occupy interstitial spaces defined between the projected cylindrical envelopes of cell 2, cell 3, and cell 4. This demonstrates that terminal placement within the interstitial geometry between cell 1 and cell 5 (FIG. 14 A) does not require corresponding alignment with interstitial regions of other battery cells positioned elsewhere within the battery assembly 740.[000317] In some embodiments, the battery' pack positive and negative power terminals 528, 529 extend along a longitudinal direction of the battery assembly 740 over a limited axial length selected to correspond to the longitudinal extent of cell 1 and cell 5, each of which may have a nominal longitudinal length of approximately 36 mm, while terminating axially short of cell 2, cell 3, and cell 4. Although the projected outlines 1430, 1429 of the terminals may overlap projected cylindrical envelopes of cell 2, cell 3, or cell 4 when viewed in projection (FIG. 14B), the terminals are longitudinally offset from those battery cells and do not physically’ contact or interfere with them.[000318] In such embodiments, the battery pack positive and negative power terminals 528, 529 may extend along at least a majority portion of the longitudinal length of cell 1 and cell 5, while extending no more than a minor portion, or not at all, along longitudinal extents of cell 2, cell 3, or cell 4. By way of non-limiting example, the battery pack positive and negative power terminals 528, 529 may extend longitudinally by approximately 15 mm to 40 mm, 18 mm to 35 mm, or 20 mm to 30 mm, or approximately 40% to 85%, 50% to 70%, or 55% to 60% of a battery’ cell length. In some embodiments, the battery’ pack positive and negative power terminals 528, 529 terminate at least approximately 1 mm, 2 mm, 3 mm, 5 mm, or 8 mm axially short of a closest portion of cell 2, cell 3, or cell 4, thereby maintaining axial separation while permitting the terminals to extend substantially along the full longitudinal length of cell 1 and cell 5.[000319] The battery assembly 740 can include one or more terminals 530 positioned laterally outward of the battery’ cells. As shown in FIGS. 14A and 14B, the terminals 530 are located outside projected cylindrical envelopes of cell 1, cell 2, cell 3, cell 4, and cell 5, such that the terminals 530 do not overlap with or intrude into adjacent battery’ cells. In this arrangement, the terminals 530 are positioned in exterior regions of the battery assembly 740 that are not constrained by cell-to-cell spacing, interstitial geometry, or tangent-defined boundaries associated with the battery’ cells.[000320] Because the terminals 530 are positioned laterally outside the battery cells, the terminals 530 may extend along a greater longitudinal extent of the battery’ assembly 740 than the battery’ pack positive and negative power terminals 528, 529. In some embodiments, the terminals 530 extend longitudinally along portions of the battery’ assembly adjacent both the upper battery’ cells (cell 1 and cell 5) and the lower battery’ cells (cell 2, cell 3, and cell 4), without contacting or interfering with any of the battery cells. By way’ of non-limiting example, a terminal 530 mayP-WO-TN-2025-0009 / / 1076-0022WO Patent extend along at least approximately 60%, 70%, 80%, 90%, 95%, or 100% of an overall longitudinal length of the battery assembly 740, or may extend continuously from a region adjacent cell 1 and cell 5 to a region adjacent cell 2, cell 3, and cell 4. In some embodiments, the terminals 530 extend substantially along the full longitudinal length of the batteiy assembly 740, subject only to clearance requirements from end caps, housings, interface structures, or other non-cell components.[000321] Although illustrated as terminals 530, it will be appreciated that, in some embodiments, one or both of the battery' pack positive and negative power terminals 528, 529 may be positioned similarly to the terminals 530, such that the terminals 528 and / or 529 are located laterally outside projected cylindrical envelopes of all battery cells from one or more directions. In such embodiments, the terminals 528 and / or 529 may likewise extend along a greater longitudinal extent of the batteiy' assembly 740 without being constrained by interstitial spacing between adjacent batteiy' cells.[000322] FIG. 15A illustrates a schematic side view of the battery assembly 740 showing representative longitudinal positioning, axial alignment, and relative offset of battery cells within the assembly. As shown, the battery assembly 740 includes a first cell group 741 and a second cell group 742 arranged along a longitudinal direction corresponding generally to a pack longitudinal axis 523. The illustrated view is schematic and is provided to show relative positional relationships (e.g., axial alignment, axial offset, collinearity, and lateral offset) rather than requiring any particular absolute size, scale, or spacing.[000323] The first cell group 741 includes cell 1 and cell 5, which are positioned side-by-side (radially offset from each other / on opposite sides of the pack longitudinal axis 523) in the illustrated view. In this configuration, cell 1 and cell 5 have common end portions that are axially aligned, such that corresponding ends (e.g., upper ends as illustrated) of cell 1 and cell 5 lie in a common transverse plane. In some embodiments, axial alignment of the corresponding ends of cell 1 and cell 5 is maintained within approximately 0-5 mm, 0-3 mm, or 0-1 mm. Alternatively, cell 1 and cell 5 may be intentionally staggered, such that one end portion is axially offset relative to the other by approximately 1-10 mm, 2-8 mm, or 3-6 mm, while still being considered part of the first cell group 741.[000324] The second cell group 742 includes cell 2, cell 3, and cell 4, which are positioned below the first cell group 741 along the longitudinal direction (radially offset from each other / the pack longitudinal axis 523 in a space between all three cells). In the illustrated embodiment, cell 2 and cell 3 have corresponding end portions that are axially aligned. In some embodiments, axial alignment of corresponding ends of cell 2 and cell 3 is maintained within approximately 0-5 mm, 0-3 mm, or 0-1 mm. Cell 4 is axially offset relative to cell 2 and cell 3, such that one end portion of cell 4 is shifted longitudinally relative to corresponding end portions of cell 2 and cell 3. By way of non-limiting example, an axial offset of cell 4 relative to cell 3 and / or relative to cell 2 may be approximately 1-15 mm, 2-12 mm, 3-10 mm, or 4-8 mm. In some embodiments, where a nominal cell length is approximately 36 mm, such axial offset corresponds to approximately 3%-40%, 5%-30%, or 10%-25% of the nominal cell length. Alternatively, the axial offset may beP-WO-TN-2025-0009 / / 1076-0022WO Patent smaller (e.g.. <5 mm) or larger (e.g.. >10 mm) to accommodate tolerances, internal structures, or packaging constraints.[000325] In some embodiments, the axial offset between batter}’ cells within the second cell group 742, such as the axial offset between cell 4 and one or more of cell 2 and cell 3, provides functional advantages beyond packaging efficiency. By axially staggering adjacent batten' cells, conductive members, terminal structures, and electrical interfaces associated with different electrical potentials may be spatially separated in the longitudinal direction, thereby reducing the likelihood of unintended electrical contact, arcing, or shorting between conductive elements during assembly, operation, vibration, or deformation of the battery’ assembly 740. In some embodiments, the axial offset is selected such that conductive elements associated with relatively large voltage differentials are prevented from approaching one another within a distance sufficient to permit electrical arcing or inadvertent contact, even under manufacturing tolerances or mechanical deflection. Accordingly, the axial offset configuration may improve electrical isolation, safety, and robustness of the battery assembly 740.[000326] As further illustrated in FIG. 15 A, cell 1 and cell 2 are substantially colinear and share a common longitudinal reference axis 1502, such that principal longitudinal axes of the respective battery cells are aligned along the same longitudinal centerline. In some embodiments, “colinear" includes configurations in which the longitudinal reference axes are coincident within a lateral tolerance of approximately 0-5 mm, 0-3 mm, or 0-2 mm. Cell 3 and cell 4 are positioned laterally adjacent to one another in a side-by-side arrangement and have longitudinal axes that are substantially parallel but laterally offset, and cell 3 and cell 4 are further axially offset relative to one another along the pack longitudinal direction. In the illustrated view, the longitudinal axes of cell 3 and cell 4 are aligned in projection and share a common longitudinal reference axis 1504, notwithstanding the lateral and axial offsets between the cells. In some embodiments, the longitudinal axes of cell 3 and cell 4 are laterally offset by approximately 1-8 mm and axially offset by a corresponding distance while remaining generally aligned along the length of the battery pack and packaged as a paired region.[000327] In the illustrated configuration, cell 5 extends along a different longitudinal reference axis 1506 that is laterally offset relative to the longitudinal reference axis 1504 associated with cell 3 and cell 4, such that cell 5 is not colinear with cell 3 or cell 4. By way of non-limiting example, a lateral offset between the longitudinal reference axis 1506 of cell 5 and the longitudinal reference axis 1504 of cell 3 / cell 4 may be approximately 2-25 mm, 4-20 mm. or 6-15 mm. depending on cell size, housing constraints, and desired overall cross-sectional envelope. Alternatively, the offset may be selected such that cell 5 is radially closer to the pack longitudinal axis 523 than cell 3 and cell 4, or radially farther therefrom, while maintaining the relative 2+3 cell arrangement.[000328] The pack longitudinal axis 523 extends generally through the battery assembly 740 and represents an overall insertion axis and / or reference axis of the battery pack. In some embodiments, one or more battery cells are substantially centered about the pack longitudinal axis 523. Alternatively, one or more battery’ cells are laterally offset from the pack longitudinal axis 523, such as by approximately 1-20 mm, 2-15 mm, or 3-10 mm, to accommodate side-by-side cellP-WO-TN-2025-0009 / / 1076-0022WO Patent placement, axial staggering, and overall packaging geometry. In some embodiments, an average lateral offset of the set of battery cells from the pack longitudinal axis 523 is less than approximately 10 mm or 5 mm, while in other embodiments the set of battery cells is intentionally biased to one side such that the pack longitudinal axis 523 does not pass through a centroid of the battery cell arrangement.[000329] The relative axial alignment, collinearity, axial offset, and lateral offset relationships illustrated in FIG. 15A are provided by way of example and may be varied in other embodiments. For example, different cells within the first cell group 741 or second cell group 742 may be axially aligned or offset by differing amounts, and the longitudinal reference axes 1502, 1504, and 1506 may be laterally shifted relative to one another, provided that the resulting configuration supports desired packaging efficiency, terminal placement, electrical isolation, and integration within the battery assembly 740.[000330] FIGS. 15A-15D illustrate schematic views of the battery assembly 740 taken from different viewing orientations. In particular, FIG. 15A illustrates a left-side view, FIG. 15B illustrates a front view, FIG. 15C illustrates a right-side view, and FIG. 15D illustrates a rear view of the battery assembly 740. FIGS. 14A, 14B, and 15A-15D are intended to be considered together to illustrate representative spatial relationships between battery’ cells and battery’ pack terminals within the battery assembly 740 when viewed from different orientations. The figures convey relative positioning, alignment, offset, and projection effects of internal components, rather than requiring any particular absolute dimensions, scale, or cell geometry'.[000331] As shown across FIGS. 14A-14B and 15A-15D, the battery assembly 740 includes a first cell group 741 and a second cell group 742 positioned at different longitudinal regions of the assembly. The first cell group 741 includes cell 1 and cell 5, which are positioned side-by-side and have corresponding end portions that are axially aligned, such that their ends he in a common transverse plane. Due to this side-by-side and aligned arrangement, one of the cells may be obscured by the other when viewed from certain orientations, as illustrated in FIGS. 15B and 15D.[000332] The second cell group 742 includes cell 2, cell 3, and cell 4, which collectively form a triad of battery cells arranged within a common longitudinal region of the battery assembly 740. Within this triad, different cells exhibit different longitudinal alignment relationships. In the illustrated embodiment, cell 2 is radially aligned with cell 1 along a first longitudinal reference axis 1502. Cell 3 and cell 4 are positioned side-by-side and extend generally parallel to one another along a second longitudinal reference axis 1504 that is laterally offset from the first longitudinal reference axis 1502. In some embodiments, cell 4 is additionally axially offset relative to cell 3 and / or cell 2, such that corresponding end portions of the triad are staggered in the longitudinal direction.[000333] FIGS. 15A-15D collectively illustrate that the triad formed by cell 2, cell 3, and cell 4 includes multiple longitudinal alignment relationships within the same battery’ assembly, with the aligned subsets being laterally offset from one another. As a result of this three-dimensional positioning, portions of the triad overlap in projection when viewed from certain orientations, suchP-WO-TN-2025-0009 / / 1076-0022WO Patent as in FIGS. 15B and 15D, while the underlying longitudinal alignment relationships are more apparent when viewed from other orientations, such as in FIGS. 15A and 15C.[000334] FIGS. 14A and 14B further illustrate end views of the battery assembly 740 showing how the alignment relationships described above manifest in cross-section. In particular, FIG. 14A shows projected outlines of cell 1 and cell 5 and demonstrates placement of battery pack positive and negative power terminals 528, 529 within interior regions that do not overlap projected envelopes of the battery cells. FIG. 14B similarly shows projected outlines of cell 2, cell 3, and cell 4, illustrating that different cells of the triad occupy different lateral positions while remaining packaged within a compact transverse envelope.[000335] When FIGS. 14A, 14B, and 15A-15D are considered together, it can be seen that the apparent overlap, visibility, or relative position of individual battery cells depends on viewing orientation, and that such variation reflects the three-dimensional arrangement of the cells within the battery assembly 740. The illustrated configuration allows different subsets of battery cells to be aligned along different longitudinal reference axes while remaining integrated within a single battery assembly.[000336] The spatial relationships illustrated in FIGS. 14A, 14B, and 15A-15D are provided by way of example and may be varied in other embodiments. For example, relative axial alignment, axial offset, and lateral offset among cell 1, cell 2. cell 3, cell 4. and cell 5 may be adjusted while maintaining the principle that different subsets of cells are aligned along different longitudinal reference axes within a common battery' assembly to support compact packaging, terminal placement, and overall integration.[000337] Referring to FIGS. 11 and 15B, in some embodiments, each individual electrical interconnection member 1120 has an axial length that does not exceed an axial length of any battery cell 745 within the battery' assembly. In the illustrated configuration, electrical interconnection member 1120D, which electrically couples cell 3 to cell 4, is the only electrical interconnection member that extends along a side surface of a battery cell. As shown in FIG. 15B, cells 3 and 4 are axially offset relative to one another, such that an axial span of electrical interconnection member 1120D is shorter than a full axial length of either cell and shorter than the axial length of any other battery cell in the battery assembly. In some embodiments, the battery cells 745 are cylindrical lithium-ion cells having standardized form factors. By way of example, the battery cells 745 may include 18350-format cells having a nominal axial length of approximately 35 mm or 18650-format cells having a nominal axial length of approximately 65 mm. In such embodiments, axial dimensions of the electrical interconnection members 1120 are selected relative to the nominal axial length of the battery cells 745. For example, an axial length of each individual electrical interconnection member 1120 does not exceed the nominal axial length of any battery cell 745 within the battery assembly. In some embodiments, an axial length of electrical interconnection member 1120D is less than approximately 35 mm when used with 18350-format cells and less than approximately 65 mm when used with 18650-format cells.[000338] FIG. 16 illustrates a schematic elevation view of the battery' assembly 740 showing representative relationships between individual battery' cell longitudinal reference axes, a packP-WO-TN-2025-0009 / / 1076-0022WO Patent longitudinal axis 523, and an insertion axis 521. FIG. 16 illustrates a top-side elevation view of the battery assembly 740. This figure may be considered together with FIGS. 14A-14B and FIGS.15A-15D to further illustrate axis relationships and spatial organization within a multi-cell battery assembly, rather than to require any particular absolute geometry or symmetry.[000339] As shown, each battery cell is associated with a respective cell longitudinal reference axis, including a common longitudinal reference axis 1502 associated with cell 1 and cell 2, a longitudinal reference axis 1505 associated with cell 3, a longitudinal reference axis 1606 associated with cell 4, and a longitudinal reference axis 1506 associated with cell 5. The battery' assembly 740 further includes the pack longitudinal axis 523, which represents an overall reference axis of the battery pack, and the insertion axis 521, which represents a direction along which the battery pack may be inserted into or removed from a corresponding battery receptacle. In some embodiments, the pack longitudinal axis 523 and the insertion axis 521 are coincident or substantially coincident, while in other embodiments they are offset or angled relative to one another.[000340] FIG. 16 illustrates that the cell longitudinal reference axes are laterally offset from one another and are not required to coincide with the pack longitudinal axis 523. In the illustrated embodiment, the pack longitudinal axis 523 passes through an interior region of the battery assembly 740 located between adjacent battery cells, rather than intersecting the center of any individual battery’ cell. This configuration alloyvs multiple battery cells to be positioned along different longitudinal reference axes while maintaining a compact overall transverse envelope and a defined insertion direction for the battery' pack.[000341] The schematic view further illustrates a pair of tangent reference lines 1672 and 1674 extending generally parallel to the insertion axis 521 and positioned tangentially relative to outermost extents of selected battery' cells. In the illustrated embodiment, each of the tangent reference lines 1672 and 1674 is tangential to an exterior boundary of cell 1 and to an exterior boundary' of cell 5, such that the tangent reference lines collectively7define laterally opposed transverse boundary limits of the battery' assembly when viewed in the illustrated orientation. In this manner, the tangent reference lines establish a transverse envelope defined jointly by the outermost envelopes of cell 1 and cell 5.[000342] In this configuration, the pack longitudinal axis 523 is positioned between tangent reference lines 1672 and 1674 and extends through an interior region of the battery assembly 740 between cell 1 and cell 5. This relationship illustrates that the global reference axis of the battery assembly need not intersect a center of any individual battery cell, but may instead pass through a region bounded by tangent-defined exterior limits of adjacent cells. In other embodiments, the pack longitudinal axis 523 may be positioned closer to one of the tangent reference lines or may coincide with a tangent reference line.[000343] In some embodiments, the tangent reference lines illustrated in FIG. 16 are used as geometric reference boundaries for evaluating available interior volume, component placement regions, terminal positioning, or housing clearances yvithin the battery' assembly 740. The tangentP-WO-TN-2025-0009 / / 1076-0022WO Patent reference lines are illustrative and do not require that any component lie exactly on or coincide with such lines.[000344] The axis relationships and tangent relationships illustrated in FIG. 16 are provided by way of example and may be varied in other embodiments. For example, lateral spacing between cell longitudinal reference axes, angular relationships between the pack longitudinal axis 523 and the insertion axis 521, and relative placement of tangent reference lines may be adjusted while maintaining a battery assembly in which different subsets of cells extend along different longitudinal reference axes and collectively define interior regions suitable for compact packaging and integration within a power tool.[000345] FIGS. 17A and 17B illustrate respective views of a power tool 10 with a battery pack 500 installed in a handle assembly 12, with the pack housing and internal battery pack components omitted to illustrate the relative positioning of individual battery cells 745 with respect to the handle assembly 12 and a transitional region 508 between the handle assembly 12 and the battery pack 500.[000346] As shown, the battery pack 500 includes a plurality of elongate battery cells 745 electrically coupled to provide power to the power tool 10. The handle assembly 12 defines an interior handle volume configured to receive at least a portion of the battery pack 500. and the transitional region 508 defines a boundary’ between a portion of the battery pack 500 positioned within the handle assembly 12 and a portion of the battery’ pack 500 positioned external to the handle assembly 12.[000347] The battery pack 500 may be configured such that one or more battery cells extend into the handle assembly 12 when the battery' pack 500 is installed. In such configurations, at least a portion of at least one battery’ cell 745 is at least partially received wi thin the interior handle volume of the handle assembly 12. In some cases, one or more additional battery’ cells may remain partially or entirely external to the handle assembly 12.[000348] The extent to which one or more individual battery’ cells 745 extend into the handle assembly 12 may’ vary. For example, a portion of a single battery cell may extend into the handle assembly 12, or portions of two, three, or four battery cells may extend into the handle assembly 12. In some cases, a majority portion of one or more battery cells may be positioned within the handle assembly 12. In some configurations, a majority portion of two, three, or four battery cells may be positioned within the handle assembly 12.[000349] Multiple battery’ cells may extend into the handle assembly 12 by different amounts. For example, two battery cells may each have a portion positioned within the handle assembly 12 and one or more additional battery cells may be partially within the handle assembly 12 or remain predominantly or fully external to the handle assembly 12.[000350] FIGS. 17A and 17B illustrate one example implementation of such a configuration. In the illustrated arrangement, the battery’ pack 500 includes battery’ cells identified as cell 1, cell 2, cell 3, cell 4, and cell 5. As shown, cell 1 and cell 5 extend upwardly into the handle assembly 12 above the transitional region 508, while cell 2, cell 3, and cell 4 extend below the transitional region 508 and remain external to the handle assembly 12.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000351] In the illustrated configuration, the battery cells that extend into the handle assembly 12 do so by different axial amounts. As shown, cell 5 extends further into the handle assembly 12 than cell 1. such that a greater portion of cell 5 is positioned within the handle assembly 12 as compared to cell 1. In this arrangement, a majority portion of cell 5 is positioned within the handle assembly 12, while a portion of cell 1 is positioned within the handle assembly 12 and a remaining portion of cell 1 extends below the transitional region 508.[000352] As further illustrated, cell 2, cell 3, and cell 4 are positioned entirely external to the handle assembly 12, with their respective axial lengths extending below the transitional region 508. The illustrated configuration demonstrates that individual battery cells 745 may extend into the handle assembly 12 to different extents, including configurations in which some battery cells extend into the handle assembly 12 while other battery cells remain fully external thereto, while remaining electrically coupled as part of a common battery pack 500.[000353] It will be appreciated that the number of battery cells that extend at least partially into the handle assembly 12 may vary across embodiments. In some configurations, only a single battery cell extends at least partially into the handle assembly 12. In other configurations two, three, or four battery cells extend at least partially into the handle assembly 12. The remaining battery cells, if any, may remain partially or entirely external to the handle assembly 12.[000354] The extent to which a battery cell extends into the handle assembly 12 may vary. For example, an individual battery cell may have approximately 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, or substantially 100 percent of its axial length positioned within the handle assembly 12. In some configurations, different battery cells extend into the handle assembly 12 by different respective percentages, such that one battery cell is predominantly positioned within the handle assembly 12 while another battery cell is only partially positioned therein. In other configurations, multiple battery cells extend into the handle assembly 12 by similar or identical percentages.[000355] In some embodiments, the axial extent of a battery cell positioned within the handle assembly 12 corresponds to a selected axial length of the battery cell being received within the interior handle volume. For example, a battery cell may extend into the handle assembly 12 by a relatively small axial length such that a substantial portion of the battery cell remains external to the handle assembly 12, by a larger axial length such that a majority portion of the battery cell is positioned within the handle assembly 12, or by an axial length such that substantially an entirety of the battery cell is positioned within the handle assembly 12. The axial length by which each battery cell extends into the handle assembly 12 may be selected independently for each battery¬ cell.[000356] In some embodiments, a battery- cell may extend into the handle assembly 12 by approximately 20 mm, 33 mm, 45 mm, 52 mm, 58 mm, or up to approximately 65 mm, with a remaining portion of the battery cell extending external to the handle assembly 12.[000357] FIGS. 18A, 18B, 18C, 18D, 18E, and 18F illustrate the power tool 10 of FIG. 1, showing orthogonal views of the power tool 10 with a battery pack 1800 coupled thereto. Collectively, these views illustrate the external geometry, handle integration, and ergonomicP-WO-TN-2025-0009 / / 1076-0022WO Patent relationship between the handle assembly 12 and the battery pack 1800 in an installed configuration. In particular, FIGS. 18A-18F illustrate a left-side elevation view, a front elevation view, a right-side elevation view, a rear elevation view, a top elevation view, and a bottom elevation view, respectively, of the power tool 10 and the battery pack 1800.[000358] As compared to FIGS. 5A-5F, FIGS. 18A-18F illustrate the power tool 10 with a different battery pack 1800 coupled to the handle assembly 12 in place of the battery pack 500. Except for the battery pack 1800, the power tool 10 shown in FIGS. 18A-18F may be the same as described herein. In some embodiments, the battery' pack 1800 differs from the battery' pack 500 in some internal battery' architecture, such as the axial distribution, grouping, and / or orientation of battery cells, while including the same total number of battery' cells as the battery' pack 500. By way of non-limiting example, both the battery pack 1800 and the battery pack 500 may include five battery cells electrically coupled in series, while differing in how those battery cells are grouped, positioned, or oriented within the respective pack housings. In some embodiments, the battery pack 1800 provides a different electrical configuration, energy capacity, voltage profile, or internal packaging arrangement as compared to the battery pack 500, while remaining compatible with the handle assembly 12 and the power train assembly 11. Despite such differences, the battery pack 1800 is configured to be received by the handle assembly 12 and to cooperate with the handle assembly 12 to define composite grip region 1891 in a manner similar to that described herein with respect to the battery pack 500. Accordingly, FIGS. 18A-18F illustrate an alternative battery pack embodiment installed on the same power tool platform, demonstrating interchangeability of battery pack architectures while preserving overall tool geometry, handle integration, and user ergonomics.[000359] Referring to FIGS. 18A-18F, the power tool 10 includes the handle assembly 12 and the power train assembly 11 coupled to the handle assembly 12. The power train assembly 11 is configured to house an electric motor and associated drive components and defines the output axis 17. The handle assembly 12 includes a user-engageable grip surface extending generally along the handle axis 19 and supports user-actuatable controls, including the trigger 22, as described herein.[000360] The battery pack 1800 includes a pack housing 1802 extending along a pack longitudinal axis 1823. The pack housing 1802 includes a first housing portion 1804 (not visible in FIGS. 18A-18F) configured to be received within a battery receptacle cavity of the handle assembly 12, a second housing portion 1806 configured to remain external to the handle assembly 12 when the battery pack 1800 is installed, and a transitional region 1808 positioned between the first housing portion 1804 and the second housing portion 1806. In the installed configuration shown in FIGS. 18A-18F, the second housing portion 1806 defines an external grip section of the battery pack 1800 that cooperates with the handle assembly 12 to define a composite grip region 1891 extending generally along the handle axis 19, including an upper grip region 1832 defined primarily by the handle assembly 12, a lower grip region 1834 defined primarily by the battery' pack 1800, and a transition grip region 1836 positioned at the transitional region 1808. The battery' pack 1800 further includes a loyver base portion 1825 positioned at a loyver end of the pack housing 1802, yvith the loyver base portion 1825 supporting one or more user-interface features 1822.P-WO-TN-2025-0009 / / 1076-0022WO Patent Except as otherwise described herein, the external geometry, handle integration, grip-surface relationships, dimensional relationships, ergonomic characteristics, and interface behavior of the battery pack 1800 relative to the handle assembly 12 may be the same as or similar to those described herein with respect to the battery’ pack 500, while internal structure, battery-cell arrangement, and electrical architecture of the battery' pack 1800 may differ as described elsewhere herein.[000361] FIG. 18G illustrates a power tool 1810 shown in a representative operating configuration in which a user’ s hand is positioned on a handle assembly 12 of the power tool 1810. The power tool 1810 may be an embodiment of the power tool 10 described herein and may include any suitable features, components, or configurations described with respect to the power tool 10. In some embodiments, the power tool 1810 is configured to selectively receive and operate with different battery packs, including the battery pack 500, the battery pack 1800, or other battery pack embodiments described herein.[000362] As shown in FIG. 18G, the handle assembly 12 supports the trigger 22 and defines a user-engageable grip region configured to be grasped by a user during operation. A gnp registration line or grip registration plane 1900 is illustrated as a reference feature extending through a central region of the trigger 22 and generally along a direction parallel to the output axis 17 of the power tool 1810. In the illustrated embodiment, the grip registration line or grip registration plane 1900 is positioned substantially coincident with a center of curvature of an upper rear recurve portion of the handle assembly 12.[000363] The grip registration line or grip registration plane 1900 defines a reference datum representative of a nominal or expected hand position of a user when the handle assembly 12 is grasped in an operating grip configuration. In such a configuration, an index finger of the user is positioned to actuate the trigger 22, while remaining fingers wrap around the handle assembly 12 and, in some embodiments, extend onto a portion of an attached battery pack, such as the battery pack 500 or the battery’ pack 1800.[000364] The grip registration line or grip registration plane 1900 permits ergonomic and structural relationships of the power tool 1810 to be described, evaluated, or claimed relative to a human-interface reference rather than solely relative to geometric tool axes. For example, positions of pack housings, battery cells, internal components, centers of mass, grip transitions, or housing contours may be referenced relative to the grip registration line or grip registration plane 1900 to characterize balance, reach, w rist alignment, trigger access, or distribution of gripping forces during operation.[000365] In some embodiments, the grip registration line or grip registration plane 1900 remains substantially consistent across different battery' pack configurations, such that substitution of the battery’ pack 500 with the battery' pack 1800 does not materially alter the nominal hand position on the handle assembly 12. In this manner, FIG. 18G illustrates an anatomy-informed ergonomic reference that supports interchangeability' of battery' pack architectures while preserving consistent user grip, control, and handling characteristics of the power tool 1810.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000366] In an operating grip configuration referenced to the grip registration line or grip registration plane 1900, the handle assembly 12 and an attached batten’ pack, such as the battery pack 500 orthe battery pack 1800, collectively define a composite grip region 591, 1891 extending along the handle axis. In such a configuration, a user’s hand spans the composite grip region 591, 1891 such that different fingers of the user’s hand engage different portions of the composite grip region 591, 1891.[000367] In some embodiments, when the grip registration line or grip registration plane 1900 is occupied, a proximal portion of the user’s hand engages the handle assembly 12 and a distal portion of the user’s hand engages the battery' pack 500 or the battery pack 1800. For example, in some embodiments, an index finger is positioned to actuate the trigger 22, one or more additional fingers (e.g., a middle finger and / or a ring finger) engage the handle assembly 12, and one or more remaining fingers (e g., a ring finger and / or a little finger) engage an exterior surface of the battery pack 500 or 1800 while occupying the composite grip region 591, 1891.[000368] In some embodiments, the exterior surface of the battery pack 500 or 1800 engaged by the user’s finger corresponds to a second housing portion of the battery pack 500 or 1800 that remains external to a battery receptacle of the handle assembly 12 when installed. In such embodiments, the second housing portion is positioned axially adjacent the handle assembly 12 along the handle axis and cooperates with the handle assembly 12 to define a continuous or substantially continuous grip surface forming part of the composite grip region 591. 1891. In an operating grip configuration referenced to the grip registration line or grip registration plane 1900, a lower finger of the user’s hand, including a little finger, may engage the second housing portion while the index finger engages the trigger 22 and one or more other fingers engage the handle assembly 12 within the composite grip region 591, 1891.[000369] In some embodiments, two fingers of the user’s hand engage the handle assembly 12 while at least one finger engages the battery pack 500 or 1800 when the composite grip region 591, 1891 is occupied. In other embodiments, three fingers of the user’s hand engage the handle assembly 12 while at least one finger engages the battery pack 500 or 1800. In still other embodiments, two or more fingers engage the battery pack 500 or 1800 while one or more fingers engage the handle assembly 12, all within the composite grip region 591, 1891.[000370] The distribution of fingers between the handle assembly 12 and the battery pack 500 or 1800 may vary depending on hand size, grip posture, or user preference while remaining referenced to the grip registration line or grip registration plane 1900. Regardless of such variation, the composite grip region 591. 1891 is configured such that at least one finger of the user’s hand engages the handle assembly 12 and at least one finger engages the battery' pack 500 or 1800 in the operating grip configuration.[000371] In some embodiments, when the battery pack 500 or 1800 is matingly received in the power tool 1810, at least a portion of a tool-facing end of the battery pack 500 or 1800 and one or more battery pack electrical terminals are positioned upward of the grip registration line or grip registration plane 1900. In some embodiments, the battery pack electrical terminals are positioned above the grip registration line or grip registration plane 1900 by approximately 0-10 mm, 0-15P-WO-TN-2025-0009 / / 1076-0022WO Patent mm, 0-20 mm, or 0-25 mm when the battery pack 500 or 1800 is fully seated. In some embodiments, the battery pack electrical terminals are positioned at least approximately 9 mm above the grip registration line or grip registration plane 1900 when the battery pack 500 or 1800 is fully seated in the power tool 1810.[000372] FIGS. 18H and 181 illustrate partial cross-sectional views of apower tool 1810 showing the trigger assembly 22 supported by a handle assembly and movable relative to the handle assembly along a trigger displacement axis or trigger actuation path 1879. The trigger assembly 22 is positioned along a forward-facing surface of the handle assembly and is movable between a non-actuated position corresponding to position XI (FIG. 18H) and an actuated position corresponding to position X2 (FIG. 181) to control operation of an electric motor supported by the power tool 1810.[000373] In the illustrated embodiment, the trigger assembly 22 includes a movable trigger body 1885 having an exterior user-engageable surface 1881 configured to be contacted by a user’s finger. In some embodiments, the exterior user-engageable surface 1881 corresponds to arearmost portion of a concave, forward-facing surface of the movable trigger body 1885, providing an ergonomic interface for trigger actuation. Positions XI and X2 correspond to respective positions of the exterior user-engageable surface 1881 along the trigger displacement axis 1879. In some cases, the grip registration line or grip registration plane 1900 passes through the user-engageable surface 1881 / [000374] FIGS. 18H and 181 further illustrate a trigger-integrated battery retention interlock member 1887 operatively coupled to the trigger assembly 22. In the non-actuated position of the trigger assembly 22 corresponding to position XI, the battery retention interlock member 1887 is disposed in a first position that permits removal of a battery pack 1800 from a battery -receiving cavity of the handle assembly along a battery insertion axis 1821. In some embodiments, the battery retention interlock member 1887 is biased toward the first position by a resilient element, such as a spring, flexure, or elastomeric structure, such that the battery pack 1800 is removable when the trigger assembly 22 is not actuated.[000375] As the trigger assembly 22 is displaced from the non-actuated position XI toward the actuated position X2 along the trigger displacement axis 1879, the battery retention interlock member 1887 is correspondingly displaced from the first position toward a second position. In the second position, the battery retention interlock member 1887 extends into a boundary region of the battery pack 1800 and engages, interferes with, or otherwise restricts movement of a portion of the battery pack 1800, thereby inhibiting removal of the battery’ pack 1800 along the battery insertion axis 1821 while the trigger assembly 22 is displaced from the non-actuated position.[000376] In some embodiments, extension of the battery' retention interlock member 1887 into the boundary region of the battery pack 1800 occurs in a radial direction, an axial direction, or a combination thereof relative to the battery’ insertion axis 1821. In some embodiments, the operative coupling between the trigger assembly 22 and the battery’ retention interlock member 1887 is provided by a cam surface, linkage, slot-and-pin interface, flexure, or other motion-translatingP-WO-TN-2025-0009 / / 1076-0022WO Patent structure configured to convert trigger displacement into movement of the batten- retention interlock member 1887.[000377] In some embodiments, the battery retention interlock member 1887 cooperates with a corresponding recess, clearance region, or interlock interface 1889 formed in or adjacent to the battery pack 1800. The interlock interface 1889 provides a designated region for interaction with the battery retention interlock member 1887, enabling a friction-fit or transition-fit battery¬ insertion arrangement while restricting withdrawal of the battery pack 1800 during trigger displacement.[000378] In some embodiments, movement of the battery- retention interlock member 1887 occurs during initial displacement of the trigger assembly 22, prior to or independent of energization of the electric motor. In this manner, the trigger-based battery- retention interlock arrangement illustrated in FIGS. 18H and 181 is configured to inhibit unintended removal of the battery pack 1800 during operation of the power tool 1810, while permitting insertion and removal of the battery pack 1800 when the trigger assembly 22 is in the non-actuated position, without requiring a separate user-actuated battery release mechanism.[000379] FIGS. 18H and 18J further illustrate an embodiment in which the retention interface 544 is implemented as a hog ring disposed in the housing of the power tool. In such embodiments, the battery retention interface 544 is received within a recess or receiving space 1877 of the handle assembly 12 (and / or a terminal block housing) and projects into a battery receptacle cavity-configured to receive the battery- pack 1800 along the battery insertion axis 1821. The battery¬ retention interface 544 may be circumferentially continuous or partially- circumferential and is configured to elastically deform during insertion of the battery- pack 1800.[000380] In some embodiments, the battery- pack 1800 includes a protrusion, groove, shoulder, or circumferential feature configured to engage the battery- retention interface 544 yvhen the batterypack 1800 reaches an installed position. Insertion of the battery- pack 1800 causes elastic deformation of at least one of the battery- retention interface 544 or the cooperating feature of the battery pack 1800, such that the battery- retention interface 544 retains the battery pack 1800 in the battery receptacle by frictional and interference engagement. In some embodiments, yvhen the battery pack 1800 is installed, the battery retention interface 544 is positioned within the handle assembly 12 such that the retention interface is inaccessible from an exterior of the power tool 1810.[000381] As shown in FIGS. 18H and 181, insertion of the battery pack 1800 into the battery receptacle along the battery- insertion axis 1821 causes elastic deformation of the battery retention interface 544 as the battery retention interface 544 rides over or engages a complementary- receiving space, recess, groove, or retention boundary- 1877 formed in the housing of the power tool 1810. Once the battery pack 1800 reaches an installed position, the battery- retention interface 544 is permitted to expand, seat, or partially seat within the receiving space 1877, thereby-providing a frictional and interference-based engagement betyveen the battery- pack 1800 and the poyvertool 1810.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000382] The receiving space 1877 may be formed as an annular recess, pocket, undercut region, or local enlargement of the battery receptacle and may be defined at least in part by a housing portion of the handle assembly or by a terminal block housing disposed within the handle assembly. In some embodiments, the receiving space 1877 is positioned such that, when the battery’ pack 1800 is installed, the battery retention interface 544 is at least partially surrounded by housing structure of the power tool 1810, rendering the battery retention interface 544 inaccessible from an exterior of the power tool.[000383] The engagement between the battery’ retention interface 544 and the receiving space 1877 is configured to resist axial withdrawal of the battery’ pack 1800 from the battery’ receptacle during use while permitting intentional removal when sufficient withdrawal force is applied. In some embodiments, retention is achieved without a user-actuated latch, relying instead on elastic deformation of the battery' retention interface 544, frictional interaction, and geometric interference between the battery’ retention interface 544 and the receiving space 1877. Such an arrangement is particularly suited for friction-fit or transition-fit battery insertion architectures.[000384] In some embodiments, the receiving space 1877 and the battery retention interface 544 together form part of a battery retention assembly that is at least partially disposed within the battery receptacle and at least partially disposed within a terminal block housing or adjacent structural portion of the handle assembly. In such embodiments, the battery retention interface 544 may be considered a rigid detent element configured to engage a corresponding protrusion, groove, or circumferential feature of the battery' pack 1800, with insertion of the battery pack 1800 causing elastic deformation of at least one of the battery retention interface 544 or the battery pack housing.[000385] FIG. 18 J illustrates a top view of the power tool 1810 showing the receiving space 1877 positioned within the housing and aligned with the battery' receptacle. FIG. 18 J further illustrates how the receiving space 1877 may be circumferentially continuous or partially circumferential, and how the receiving space 1877 is positioned to cooperate with the battery retention interface 544 when the battery pack 1800 is installed. In some embodiments, the receiving space 1877 is configured to accommodate manufacturing tolerances, assembly variation, and wear while maintaining consistent retention characteristics.[000386] In some embodiments, the power tool 1810 includes a sensing arrangement configured to detect presence of the battery pack 1800 by detecting a position or state of the battery retention interface 544 relative to the receiving space 1877. Such a sensing arrangement may include, by way of non-limiting example, a conductive sensor, a Hall-effect sensor, an inductive sensor, or a positional switch responsive to movement or seating of the battery retention interface 544.[000387] In other embodiments, the battery retention interface 544 is supported by the battery' pack 1800 rather than by the housing of the power tool 1810. In such embodiments, the battery' retention interface 544 may be implemented as a radially spring-biased circumferential retention feature, such as a hog ring, disposed in a circumferential groove or recess formed in a housing portion of the battery' pack 1800. The battery' retention interface 544 is configured to elastically deform during insertion of the battery pack 1800 into the battery receptacle and to expand or seat into a complementary receiving space, recess, or retention feature formed in the handle assemblyP-WO-TN-2025-0009 / / 1076-0022WO Patent 12 or terminal block housing of the power tool 1810 when the batten’ pack 1800 reaches an installed position. In such embodiments, engagement between the batten’ retention interface 544 and the complementary receiving space provides frictional and interference-based retention of the battery pack 1800 within the battery receptacle.[000388] FIGS. 19A, 19B, 19C, 19D, 19E, and 19F illustrate left-side elevation, front elevation, right-side elevation, rear elevation, top elevation, and bottom elevation views, respectively, of the battery pack 1800 in accordance with the present disclosure. As shown, the battery pack 1800 includes a pack housing 1802 defining an elongate body extending along a pack longitudinal axis 1823.[000389] The battery pack 1800 includes a pack housing 1802 defining a first housing portion 1804 and a second housing portion 1806. The first housing portion 1804 defines an insertable section of the battery pack 1800 that is configured to be at least partially received within the battery receptacle cavity 115 of the handle assembly 12 along an insertion axis 1821. The second housing portion 1806 defines an external section of the battery pack 1800 that remains outside the handle assembly 12 when the battery pack 1800 is installed.[000390] The first housing portion 1804 of the pack housing 1802 can be an embodiment of, and / or can be dimensioned, shaped, or configured in a manner similar to, the first housing portion 504 of the battery pack 500 described herein, such that the first housing portion 1804 is configured to be received within the batter ’ receptacle cavity 115 in substantially the same manner as the battery pack 500. In some embodiments, the first housing portion 1804 mirrors the geometry of the battery pack interface region so as to occupy the same interface region within the battery' receptacle cavity 115. In some embodiments, any suitable dimensions, contours, interface features, retention features, or geometric characteristics described herein with respect to the first housing portion 504 may likeyvise apply to the first housing portion 1804, individually or in combination, to the extent applicable.[000391] The second housing portion 1806 extends from the first housing portion 1804 and is positioned adjacent a lo ver end region of the handle assembly 12 when the battery pack 1800 is installed. In some embodiments, the second housing portion 1806 is contoured to generally folloyv or continue an exterior profile of the handle assembly 12 such that exterior surfaces of the second housing portion 1806 cooperate with exterior grip surfaces of the handle assembly 12 to define a continuous or substantially continuous grip region.[000392] In some embodiments, the second housing portion 1806 of the battery pack 1800 can be an embodiment of, and / or can be dimensioned, shaped, or configured in a manner similar to, the second housing portion 506 of the battery' pack 500 described herein. For example, the second housing portion 1806 may have the same or similar exterior geometry, transverse envelope, grip surface characteristics, ergonomic contours, and interface relationships relative to the handle assembly 12 as those described herein with respect to the second housing portion 506.[000393] In some embodiments, any suitable dimensional relationships, perimeter relationships, yvidth-to-thickness relationships, cross-sectional-area relationships, and / or axial contour progression relationships described herein yvith respect to the second housing portion 506 of theP-WO-TN-2025-0009 / / 1076-0022WO Patent battery pack 500 may likewise apply to the second housing portion 1806, individually or in combination, to the extent applicable.[000394] In some embodiments, the second housing portion 1806 defines an external grip section of the battery’ pack 1800 that remains outside the battery receptacle cavity’ 115 of the handle assembly 12 when installed and cooperates with the handle assembly 12 to define a composite grip region, as described herein. In such embodiments, the second housing portion 1806 occupies substantially’ the same grip interface region relative to the handle assembly 12 as the second housing portion 506, notwithstanding differences in internal battery’ architecture.[000395] In some embodiments, the second housing portion 1806 has an axial length that is shorter than that of the second housing portion 506, for example due to the use of smaller battery cells, a different cell grouping arrangement, or a different internal packaging architecture. In other embodiments, the axial length of the second housing portion 1806 is generally similar to that of the second housing portion 506, while differing primarily in internal configuration rather than external geometry.[000396] A transitional region 1808 is positioned between the first housing portion 1804 and the second housing portion 1806 of the pack housing 1802. The transitional region 1808 defines a geometric and functional transition between the insertable section defined by the first housing portion 1804 and the external section defined by the second housing portion 1806. In some embodiments, the transitional region 1808 of the battery pack 1800 can be an embodiment of, and / or can be dimensioned, shaped, or configured in a manner similar to, the transitional region 508 of the battery pack 500 described herein. For example, the transitional region 1808 may define any suitable stepped, sloped, tapered, radiused, curved, or blended surface geometry as described herein with respect to the transitional region 508, to the extent applicable.[000397] In some embodiments, the transitional region 1808 defines an axial stop surface configured to engage or face a corresponding surface of the handle assembly 12 when the battery pack 1800 is received within the battery receptacle cavity 115, thereby limiting insertion depth and / or providing a load-bearing interface between the battery pack 1800 and the handle assembly 12 during operation. In some embodiments, any suitable dimensions, contour progressions, axial offsets, transverse offsets, interface relationships, or load-transfer characteristics described herein with respect to the transitional region 508 of the battery pack 500 may likewise apply to the transitional region 1808, individually or in combination, to the extent applicable. In some embodiments, the location, axial extent, or profile of the transitional region 1808 may differ from that of the transitional region 508, for example due to differences in internal battery architecture or housing length, while maintaining functional equivalence in handle integration and grip continuity'.[000398] In the installed configuration, the transitional region 1808 is positioned adjacent an interface boundary’ between the handle assembly 12 and the battery’ pack 1800 and contributes to a continuous or composite grip region spanning the handle assembly 12 and the second housing portion 1806, as described herein.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000399] FIG. 20A illustrates a first exploded isometric view in which internal components are separated from the pack housing 1802 along the insertion axis 1821, and FIG. 20B illustrates a second exploded isometric view from an opposing circumferential orientation relative to FIG. 20A.[000400] The battery pack 1800 includes an internal battery assembly 1840 configured to be received within the pack housing 1802. The battery assembly 1840 extends along a longitudinal axis that is generally coincident with the insertion axis 1821 when the battery pack 1800 is assembled.[000401] As compared to the battery pack 500, the battery7assembly 1840 of the battery7pack 1800 includes three axially arranged cell groups rather than two. In the illustrated embodiment, the battery assembly 1840 includes a first cell group 1841, a second cell group 1842, and a third cell group 1843 positioned at different axial locations along the longitudinal axis of the battery assembly 1840.[000402] In the configuration illustrated in FIGS. 20A and 20B, the battery assembly 1840 includes a total of five battery cells 1845 arranged as three axially stacked cell groups and electrically connected in a single series electrical circuit. The first cell group 1841 includes two battery cells 1845, the second cell group 1842 includes two battery cells 1845, and the third cell group 1843 includes one cylindrical battery cell 1845. In some embodiments, the number of battery cells 1845 in one or more of the first, second, or third cell groups 1841, 1842, 1843 may be varied to achieve a desired electrical capacity7, voltage, or form factor, while maintaining a multi-group battery cell arrangement including at least one cylindrical battery cell oriented non-parallel to the insertion axis 1821.[000403] The first cell group 1841 includes two battery cells 1845 arranged generally side-by-side (radially offset from each other). Each cylindrical battery cell 1845 of the first cell group 1841 has a longitudinal axis oriented generally parallel to the insertion axis 1821. In the configuration illustrated in FIGS. 20A and 20B, the battery7cells 1845 of the first cell group 1841 are positioned at substantially^ the same axial location relative to one another along the insertion axis 1821. In some embodiments, one or both battery cells 1845 of the first cell group 1841 may be axially offset relative to one another, such that corresponding axial ends of the battery cells are not aligned along the insertion axis 1821.[000404] The second cell group 1842 includes two battery cells 1845 arranged generally side-by-side (radially offset from each other) and positioned axially adjacent the first cell group 1841. Each cylindrical battery cell 1845 of the second cell group 1842 has a longitudinal axis oriented generally parallel to the insertion axis 1821. In some embodiments, at least one, or both, battery¬ cells 1845 of the second cell group 1842 are generally colinear with corresponding battery cells 1845 of the first cell group 1841, such that the respective longitudinal axes of the colinear battery7cells are substantially aligned along a common line.[000405] In some embodiments, the battery7cells 1845 of the second cell group 1842 are positioned at substantially the same axial location relative to one another, such that corresponding axial ends of the battery cells are generally aligned along the insertion axis 1821. In other embodiments, at least two battery7cells 1845 of the second cell group 1842 are axially' offsetP-WO-TN-2025-0009 / / 1076-0022WO Patent relative to one another, such that one cylindrical batten' cell is positioned slightly forward or rearward of the other along the insertion axis 1821.[000406] The third cell group 1843 includes one battery cell 1845 having a longitudinal axis oriented non-parallel to the insertion axis 1821. In some embodiments, the longitudinal axis of the battery cell 1845 of the third cell group 1843 is oriented substantially perpendicular to the insertion axis 1821.[000407] In some embodiments, the first cell group 1841 and at least a portion of the second cell group 1842 are configured to be received substantially within an interior volume of a handle of a power tool when the battery pack 1800 is installed, while the third cell group 1843 is configured to remain at least partially external to the handle. In such configurations, the battery pack 1800 positions a majority of battery mass within the handle while permitting a batter}' pack housing 1802 surrounding the third cell group 1843 and / or at least part of the second cell group 1842 to define an external grip region that cooperates with a handle housing of the power tool to form a continuous grip profile.[000408] The internal battery assembly 1840 of the battery pack 1800 may include internal support structures, partitioning walls, support bosses, and / or electrical interconnection members that are the same as or similar to those described herein with respect to the battery pack 500, except as demanded by the inclusion of the third cell group 1843 and the transverse orientation of the battery cell thereof.[000409] In some embodiments, the transverse orientation of the battery cell of the third cell group 1843 permits efficient use of available internal volume, facilitates electrical interconnection with the axially oriented battery' cells of the first and second cell groups 1841 , 1842, and facilitates a series electrical interconnection architecture in which electrical interconnection members do not cross longitudinal axes of battery cells, as described in more detail herein.[000410] FIGS. 21A, 21B, 21C, 21D, 21E, 21F, 21G, and 21H illustrate various views of the internal batter}' assembly 1840 of the battery pack 1800. The views of FIGS. 21A-21H illustrate example internal structures, battery cell arrangements, and relative positioning of battery cells 1845 within the internal battery assembly 1840. FIG. 21 A illustrates an isometric view of the internal battery assembly 1840 from a first end, and FIG. 21B illustrates an isometric view of the internal battery assembly 1840 from an opposite end. FIGS. 21C-21H illustrate multiple side, end, and plan views of the internal battery assembly 1840 taken from different angular orientations about the insertion axis 1821.[000411] The internal battery assembly 1840 includes an internal support and electrical interconnection structure 1849 configured to support, position, and electrically interconnect a plurality of battery cells 1845. The internal support and electrical interconnection structure 1849 defines cell-receiving regions that locate the batter ' cells 1845 in predetermined spatial relationships relative to one another while maintaining controlled alignment of the batter ' cells 1845 along the insertion axis 1821.[000412] In some embodiments, the internal support and electrical interconnection structure 1849 defines distinct cell-receiving regions corresponding to a first cell group 1841, a second cellP-WO-TN-2025-0009 / / 1076-0022WO Patent group 1842, and a third cell group 1843 positioned at different axial locations along the length of the internal battery assembly 1840. The internal support and electrical interconnection structure 1849 may include internal walls, partitioning features, support surfaces, retention features, insulating features, or combinations thereof configured to separate adjacent battery cells 1845, maintain spacing between battery' cells 1845, and provide structural rigidity to the internal battery' assembly 1840.[000413] The internal battery' assembly 1840 includes five battery' cells 1845, identified for reference as battery' cells 1845A (cell 1), 1845B (cell 2), 1845C (cell 3), 1845D (cell 4), and 1845E (cell 5) (individually or collectively referred to as “battery7cell 1845” or “battery' cells 1845”). The battery cells 1845 are arranged into the first cell group 1841, the second cell group 1842, and the third cell group 1843, which occupy different axial regions of the internal battery7assembly 1840. In the illustrated embodiment, the first cell group 1841 includes two battery7cells 1845 A and 1845E, the second cell group 1842 includes two battery cells 1845B and 1845D, and the third cell group 1843 includes a single battery cell 1845C. The first, second, and third cell groups 1841, 1842, 1843 are positioned sequentially along the insertion axis 1821.[000414] Battery cells 1845 of the first cell group 1841 and the second cell group 1842 are elongate and have respective longitudinal axes oriented generally parallel to the insertion axis 1821. The battery cell 1845C of the third cell group 1843 has a longitudinal axis oriented nonparallel to the insertion axis 1821 and, in some embodiments, oriented generally transverse to the insertion axis 1821. The relative positions and orientations of the battery cells 1845 within the first, second, and third cell groups 1841, 1842, 1843 are illustrated to demonstrate example spatial relationships between battery7cells located in different regions of the internal battery assembly 1840.[000415] FIG. 22 illustrates an isometric view of the internal support and electrical interconnection structure 1849 of the internal battery7assembly 1840 with the battery cells omitted for clarity7. The internal support and electrical interconnection structure 1849 includes a plurality of battery-cell receiving regions 1851, 1852, and 1853 configured to receive and support battery cells of the first cell group 1841, the second cell group 1842, and the third cell group 1843, respectively. The internal support and electrical interconnection structure 1849 further includes features configured to support and route one or more electrical interconnection conductors 2220 that electrically couple the battery cells when installed.[000416] The battery-cell receiving region 1851 is configured to receive the battery’ cells of the first cell group 1841, the battery-cell receiving region 1852 is configured to receive the battery¬ cells of the second cell group 1842, and the battery -cell receiving region 1853 is configured to receive the battery cell of the third cell group 1843. The battery -cell receiving regions 1851, 1852, and 1853 are positioned at different axial locations along the insertion axis 1821 and maintain the respective orientations of the battery7cells of the corresponding cell groups.[000417] The electrical interconnection conductors 2220 are supported by the internal support and electrical interconnection structure 1849 and are configured to electrically connect the batteryP-WO-TN-2025-0009 / / 1076-0022WO Patent cells of the first, second, and third cell groups 1841, 1842, 1843 in a single series electrical circuit when the battery cells are installed within the battery-cell receiving regions.[000418] The internal support and electrical interconnection structure 1849 includes a contoured wall region 1854 extending along a side of the battery-cell receiving regions 1851 and 1852 corresponding to the first and second cell groups 1841, 1842. The contoured wall region 1854 includes a concave surface profile shaped to follow an exterior curvature of the aligned battery cells received within the battery-cell receiving regions 1851 and 1852, thereby defining a continuous wall contour along the aligned cell groups and providing a reduced-thickness region of the internal support and electrical interconnection structure 1849 along that side.[000419] The internal support and electrical interconnection structure 1849 further includes an upper support surface 1855 positioned adjacent the battery-cell receiving region 1853 corresponding to the third cell group 1843. The upper support surface 1855 defines a generally planar support region configured to engage an interior surface of the pack housing 1802 when assembled and to provide structural support adjacent the third cell group 1843 and the electrical interconnection conductors 2220.[000420] FIGS. 23A. 23B. 23C. 23D. 23E, and 23F illustrate schematic views of the internal battery assembly 1840 of the battery pack 1800 showing representative spatial relationships among battery cells 1845. The views are schematic and are provided to illustrate relative positional relationships, including axial alignment, axial offset, collinearity, lateral offset, and viewingorientation projection effects, without requiring any particular absolute size, scale, or spacing.[000421] Referring generally to FIGS. 23A-23F, the internal battery assembly 1840 includes five battery cells 1845, identified for reference as batten' cells 1845 A (cell 1), 1845B (cell 2), 1845C (cell 3), 1845D (cell 4), and 1845E (cell 5). The battery cells 1845 are arranged into a first cell group 1841, a second cell group 1842, and a third cell group 1843 positioned at different axial locations along a longitudinal direction corresponding generally to the insertion axis 1821 and / or a pack longitudinal axis 1823.[000422] In the illustrated embodiment, the first cell group 1841 includes two battery cells 1845A (cell 1) and 1845E (cell 5). The second cell group 1842 includes two battery cells 1845B (cell 2) and 1845D (cell 4). The third cell group 1843 includes a single battery cell 1845C (cell 3). Individual battery cells of the first cell group 1841 and the second cell group 1842 have longitudinal axes oriented generally parallel to the insertion axis 1821. The battery cell 1845C (cell 3) of the third cell group 1843 has a longitudinal axis oriented non-parallel to the insertion axis 1821 and, in some embodiments, oriented generally perpendicular to the insertion axis 1821.[000423] FIG. 23 A illustrates a schematic end view of the internal battery assembly 1840 showing the first cell group 1841. In the illustrated configuration, cell 1 and cell 5 are positioned side by side and are laterally offset relative to one another. Each of cell 1 and cell 5 has a respective longitudinal reference axis, with the longitudinal reference axis 2304 associated with cell 1 and the longitudinal reference axis 2306 associated with cell 5. The schematic end view illustrates that the longitudinal reference axes of cell 1 and cell 5 are laterally spaced and do not coincide, reflecting a side by side arrangement of the cells within the first cell group 1841.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000424] FIG. 23B illustrates a schematic top view of the internal battery assembly 1840, showing the third cell group 1843 which includes the battery cell 1845C, identified as cell 3. In the illustrated configuration, cell 3 has a longitudinal axis 2308 that is oriented non parallel to the insertion axis 1821 of the battery pack 1800. In some embodiments, the longitudinal axis 2308 of cell 3 is oriented generally perpendicular to the insertion axis 1821.[000425] FIGS. 23C and 23E illustrate schematic side view showing representative axial placement and longitudinal alignment relationships among the first cell group 1841, the second cell group 1842, and the third cell group 1843 along a longitudinal direction of the internal battery assembly 1840. In the illustrated configuration, the first cell group 1841 and the second cell group 1842 occupy different axial regions of the internal battery assembly 1840, and the third cell group 1843 occupies a different axial region than the first cell group 1841 and the second cell group 1842.[000426] Cell 1 of the first cell group 1841 and cell 2 of the second cell group 1842 are positioned in an axially stacked arrangement and are colinear with one another along a common longitudinal reference axis 2304. In addition, cell 5 of the first cell group 1841 and cell 4 of the second cell group 1842 are positioned in an axially stacked arrangement and are colinear with one another along a different longitudinal reference axis 2306 that is laterally offset from the longitudinal reference axis 2304. Cell 3 of the third cell group 1843 is positioned at a different axial location and is associated with the longitudinal axis 2308.[000427] FIGS. 23D and 23F illustrate schematic projection views showing representative collinearity between axially stacked battery cells when viewed from selected orientations. In the FIG. 23D, cell 1 and cell 2 appear aligned along the longitudinal reference axis 2304. In the FIG.23F, cell 3 and cell 4 appear aligned along the longitudinal reference axis 2304. FIGS. 23D and 23F further illustrate the longitudinal axis 2308 associated with cell 3, showing representative positioning of the non-parallel battery cell relative to the axially oriented battery cells of the first and second cell groups 1841 and 1842.[000428] Collectively, FIGS. 23 A to 23F illustrate that the internal battery assembly 1840 of the battery pack 1800 includes axially oriented battery cells in the first cell group 1841 and the second cell group 1842 and includes a non-parallel battery cell in the third cell group 1843. The figures further illustrate representative lateral spacing between battery cell axes, representative collinearity between at least one battery cell of the first cell group 1841 and at least one battery cell of the second cell group 1842, and representative axial positioning of the third cell group 1843 relative to the axially oriented battery cells.[000429] FIG. 24 illustrates an isometric cross-sectional view of the battery pack 1800 showing the internal battery assembly 1840 positioned within the pack housing 1802. The cross section illustrates an axial arrangement of a plurality of battery' cells 1845 within the battery' pack housing 1802 along the insertion axis 1821 and illustrates electrical interconnection members 2220A, 2220B, 2220C, 2220D, 2220E, and 2220F (individually or collectively referred to as “electrical interconnection member 2220” or “electrical interconnection members 2220”).P-WO-TN-2025-0009 / / 1076-0022WO Patent [000430] The internal batery assembly 1840 includes a first cell group 1841 , a second cell group 1842. and a third cell group 1843 positioned at different axial locations along the insertion axis 1821. The first cell group 1841 and the second cell group 1842 include batery cells 1845 having respective longitudinal axes oriented generally parallel to the insertion axis 1821. The third cell group 1843 includes a batery cell 1845 having a longitudinal axis oriented non-parallel to the insertion axis 1821. In some cases, the third cell group 1843 has a longitudinal axis oriented generally perpendicular to the insertion axis 1821.[000431] The first cell group 1841 and the second cell group 1842 are arranged such that at least one batery7cell 1845 of the second cell group 1842 is generally colinear with a battery' cell 1845 of the first cell group 1841, such that the respective longitudinal axes of the colinear batery cells are substantially aligned along a common line. In some embodiments, the batery cells 1845 within the first cell group 1841, or within the second cell group 1842, are positioned at a common axial location such that corresponding axial ends are generally aligned. In some embodiments, the batery cells 1845 within the respective groups of the first or second cell groups 1841, 1842 are axially offset relative to one another such that one batery cell 1845 is positioned more forward or rearward of the other along the insertion axis 1821.[000432] The internal batery assembly 1840 includes one or more electrical interconnection members 2220 arranged to electrically couple the batery cells 1845 of the first, second, and third cell groups 1841, 1842, 1843 in a single series electrical circuit. The electrical interconnection members 2220 may be formed from electrically conductive material including, but not limited to, nickel, nickel-plated steel, copper, copper alloy, or other suitable conductive metals, and may be provided as stamped conductors, bent conductors, welded conductors, bus bars, or combinations thereof.[000433] In some embodiments, the electrical interconnection members 2220 include a plurality of discrete conductive members, such as a first electrical interconnection member 2220A, a second electrical interconnection member 2220B, a third electrical interconnection member 2220C, a fourth electrical interconnection member 2220D, a fifth electrical interconnection member 2220E, and a sixth electrical interconnection member 2220F. Each electrical interconnection member 2220 may be configured to electrically couple one or more batery-cell terminals and / or one or more pack terminals such that the electrical interconnection members 2220 collectively establish a continuous series electrical path through the plurality of batery cells 1845 between a batery pack negative node and a batery pack positive node.[000434] The first and sixth electrical interconnection members 2220A and 2220F define terminal conductors associated with ends of the series electrical circuit, and the second, third, fourth, and fifth electrical interconnection members 2220B, 2220C, 2220D, and 2220E define intermediate cell-to-cell electrical connections within the series electrical circuit.[000435] Each electrical interconnection member 2220 can include one or more welded electrical junctions formed at end terminals of the batery cells and a conductive portion extending between those welded electrical junctions. A weld-to-weld total distance corresponds to a length of conductive material extending between two welded electrical junctions associated with a givenP-WO-TN-2025-0009 / / 1076-0022WO Patent electrical interconnection member 2220. In some embodiments, the weld-to-weld total distance is 4.4 mm. In some embodiments, the weld-to-weld total distance is less than about 4.5 mm. In some embodiments, the weld-to-weld total distance is within a range of 3 mm to 5.7 mm.[000436] In some embodiments, the electrical interconnection members 2220 collectively define a series electrical path through the battery pack. A total weld distance corresponds to a cumulative length of conductive material extending between successive welded electrical junctions along the series electrical path defined by the electrical interconnection members 2220. In some embodiments, the total weld distance is 20.2 mm. In some embodiments, the total weld distance is less than about 25 mm. In some embodiments, the total weld distance is within a range of 20 to 30 mm.[000437] In some embodiments, an average weld distance corresponds to an average spacing between successive welded electrical junctions formed by adjacent electrical interconnection members 2220 along the series electrical path. In some embodiments, the average weld distance is 5.05 mm. In some embodiments, the average weld distance is less than about 6 mm. In some embodiments, the average weld distance is within a range of 4.8 to 6.2 mm.[000438] In some embodiments, the electrical interconnection architecture is further characterized by a weld-to-weld average deviation, which corresponds to variation in spacing between successive welded electrical junctions formed by the electrical interconnection members 2220. In some embodiments, the weld-to-weld average deviation is 1.3 mm. In some embodiments, the weld-to-weld average deviation is less than about 1.5 mm. In some embodiments, the weld-to-weld average deviation is within a range of 0 to 2 mm.[000439] In some embodiments, the electrical interconnection members 2220 are further characterized by a controlled volume of conductive material forming the welded electrical junctions and the conductive portions extending between adjacent battery cells. In some embodiments, a total conductive volume of the electrical interconnection members 2220 is 0.649 cubic centimeters. In some embodiments, the total conductive volume is less than about 0.650 cubic centimeters. In some embodiments, the total conductive volume is within a range of 0.500 to 1.100 cubic centimeters.[000440] In some embodiments, the electrical interconnection members 2220 are further characterized by a controlled mass of conductive material forming the welded electrical junctions and the conductive portions extending between adjacent batten’ cells. In some embodiments, the total mass of conductive material forming the electrical interconnection members 2220 is 5.776 grams. In some embodiments, the total mass is less than about 6.0 grams. In some embodiments, the total mass is within a range of 4.450 to 9.790 grams.[000441] The electrical interconnection members 2220 enable a single series electrical path through the plurality of battery’ cells 1845. Along the series electrical path, a plurality of electrically distinct connection points or nodes are defined and may be referenced as node NN0 (at a terminal electrical interconnection member 2220 A), node NN1 (at an electrical interconnection member 2220B), node NN2 (at an electrical interconnection member 2220C), node NN3 (at an electrical interconnection member 2220D), nodeNN4 (at an electrical interconnection member 2220E), andP-WO-TN-2025-0009 / / 1076-0022WO Patent node NN5 (at a terminal electrical interconnection member 2220F). Each node corresponds to a physical electrical junction between adjacent battery cells 1845 or between a battery cell 1845 and a terminal conductor of the battery pack 1800.[000442] Node NN0 corresponds to a first end of the series electrical circuit and node NN5 corresponds to a second end of the series electrical circuit. Nodes NN1-NN4 correspond to intermediate nodes located between adjacent battery cells 1845 connected in series. The node identifiers NN0-NN5 denote relative positions along the series electrical path and do not denote fixed or absolute voltage values.[000443] In some embodiments, node NN0 corresponds to a battery pack negative node and node NN5 corresponds to a battery pack positive node. Because the battery cells 1845 are electrically connected in series, an electrical potential at each successive node NN 1-NN5 relative tonodeNNO increases cumulatively as additional battery cells 1845 are added in series. By way of non-limiting example, node NN1 may correspond to approximately one cell voltage relative to node NN0, node NN2 may correspond to approximately two cell voltages, node NN3 may correspond to approximately three cell voltages, node NN4 may correspond to approximately four cell voltages, and node NN5 may correspond to approximately five cell voltages.[000444] The voltage contribution of each battery cell 1845 may vary’ depending on chemistry, state of charge, temperature, or operating condition. Accordingly, node potentials are described as approximate and illustrative rather than limiting. By way of non-limiting example, in embodiments employing lithium-ion battery cells 1845 having a nominal voltage of approximately 3.6 volts to approximately 3.7 volts per cell, node NN1 may be approximately 3.6-3.7 volts relative to node NN0, node NN2 may be approximately 7.2-7.4 volts, node NN3 may be approximately 10.8-11.1 volts, node NN4 may be approximately 14.4-14.8 volts, and node NN5 may be approximately 18.0-18.5 volts. In embodiments employing lithium-ion battery’ cells 1845 having a maximum charged voltage of approximately 4.2 volts per cell, node NN1 may be approximately 4.2 volts, node NN2 may be approximately’ 8.4 volts, node NN3 may’ be approximately 12.6 volts, node NN4 may be approximately 16.8 volts, and node NN5 may be approximately 21.0 volts, each relative to node NN0. In other embodiments, different chemistries, nominal voltages, maximum charged voltages, and series cell counts may be used, and the node voltages may vary accordingly.[000445] FIGS. 25 A and 25B illustrate views of a power tool 10 with the battery pack 1800 received by ahandle assembly 12 of the power tool. Portions of the handle assembly 12 and / or the battery pack 1800 are shown in outline, phantom, or section to permit simultaneous visualization of exterior handle geometry and internal components of the battery pack 1800, including the internal battery assembly 1840. The configuration illustrated in FIGS. 25A and 25B shows the battery pack 1800 coupled to the handle assembly 12 in place of other battery' pack embodiments described herein.[000446] FIG. 2 A illustrates the power tool 10 with the battery' pack 1800 installed, with portions of the pack housing omitted or rendered transparent such that individual battery' cells 1845 of the internal battery assembly 1840 are visible. FIG. 25 A is provided to illustrate the spatial relationship between the battery cells 1845 and the handle assembly 12 when the battery’ pack 1800P-WO-TN-2025-0009 / / 1076-0022WO Patent is installed, including the orientation and relative positioning of the battery cells 1845 with respect to the handle assembly 12.[000447] FIG. 25B illustrates a cross-sectional view of the power tool 10 with the battery pack 1800 received by the handle assembly 12. In FIG. 25B, portions of the handle assembly 12 and the battery pack 1800 are shown in section to permit visualization of the internal battery assembly relative to the handle assembly 12. FIGS. 25A and 25B further illustrates an end edge 1016 of a lower handle region 114, thereby identifying a boundary' between of an exterior region below the handle assembly 12.[000448] FIGS. 25 A and 25B illustrate the relative positioning of a plurality of battery' cells 1845 with respect to a handle assembly 12 when a battery' pack is installed on a power tool. The illustrated views emphasize how individual battery cells 1845 are positioned relative to an interior volume of the handle assembly 12 and an exterior region below the handle assembly 12 when the battery pack is in an installed configuration.[000449] The handle assembly 12 includes a lower handle region 114 that terminates at an end edge 1016. The end edge 1016 defines a boundary between an interior volume of the handle assembly 12 and an exterior region below the handle assembly 12. The end edge 1016 provides a spatial reference for evaluating the extent to which individual battery cells 1845 are positioned within or outside the handle assembly 12.[000450] In the illustrated configuration, battery cells 1845 extend across the end edge 1016 such that different portions of the battery cells are positioned on opposite sides of the end edge 1016. This arrangement allows a portion of the battery cells 1845 to be located within the interior volume of the handle assembly 12 while other portions of the battery' cells 1845 are positioned externally to the handle assembly 12.[000451] The relative positions of the battery' cells 1845 with respect to the end edge 1016 show n in FIGS. 25A and 25B illustrate the extent to which portions of the battery' cells 1845 are received w ithin the handle assembly 12 in the installed configuration.[000452] In some embodiments, battery cells 1845 of the first cell group 1841 are positioned substantially within the interior volume of the handle assembly 12 above the end edge 1016. In some embodiments, a lowermost portion of one, some, or each battery cell 1845 of the first cell group 1841 is positioned above the end edge 1016 such that the entirety of that battery cell 1845 is located within the handle assembly’ 12. In some embodiments, each battery cell 1845 of the first cell group 1841 is fully received within the handle assembly 12.[000453] In some embodiments, a substantial portion of one, some, or each battery cell 1845 of the first cell group 1841 is positioned within the handle assembly 12. including at least approximately 75 percent, 80 percent, 85 percent, or substantially 100 percent of a volume of a particular battery cell 1845 of the first cell group 1841.[000454] In some embodiments, battery' cells 1845 of the second cell group 1842 are positioned such that a portion of each battery' cell 1845 extends into the interior volume of the handle assembly 12 while a remaining portion of each battery cell 1845 remains external to the handle assembly 12. In some embodiments, the battery' cells 1845 of the second cell group 1842 straddle the endP-WO-TN-2025-0009 / / 1076-0022WO Patent edge 1016 such that opposing axial portions of the battery cells 1845 are positioned on opposite sides of the end edge 1016.[000455] In some embodiments, battery cells 1845 of the third cell group 1843 are positioned predominantly externally to the handle assembly 12 below the end edge 1016. In some embodiments, a majority of a volume of the battery cell 1845 of the third cell group 1843 is positioned external to the handle assembly 12.[000456] The relative positioning of the first cell group 1841, the second cell group 1842, and the third cell group 1843 with respect to the end edge 1016 provides a battery architecture in which multiple battery' cells 1845 are positioned within the handle assembly 12 while at least one battery' cell 1845 remains external to the handle assembly 12. This arrangement positions a portion of battery mass within the handle assembly 12 to improve balance and handling characteristics of the power tool.[000457] In some embodiments, at least two battery’ cells 1845 are positioned substantially within the handle assembly 12, at least one battery' cell 1845 is positioned partially within the handle assembly 12, and at least one battery cell 1845 is positioned predominantly external to the handle assembly 12. In other embodiments, different distributions of battery cells 1845 relative to the handle assembly 12 may be employed while maintaining a multi-group battery cell architecture.Exemplary Dimensional and Performance Characterization[000458] The following section provides exemplary dimensional, geometric, and electrical performance characteristics associated with battery' packs described herein, including battery pack 500 (e.g., the 2-over-3 battery cell configuration described with reference to FIGS. 5A-17B) and battery pack 1800 (e.g., the 2-2-1 battery' cell configuration described with reference to FIGS. ISA-2513), as coupled to a power tool 10.[000459] The characteristics set forth below are provided to illustrate representative dimensional relationships, interface geometries, and electrical capabilities associated with certain embodiments and configurations. The values are exemplary and non-limiting. In some embodiments, one or more of the characteristics may fall within the ranges identified, while in other embodiments different values, ranges, or combinations may be used without departing from the scope of the disclosure.[000460] Unless otherwise noted, the dimensional and electrical characteristics described below may apply to battery packs configured to be removably coupled to the handle assembly 12 of the power tool 10 and to electrically interface with corresponding tool-side terminals and internal electrical components, as described elsewhere herein.Representative Battery Pack-to-Tool Interface Geometry[000461] In some embodiments, the battery pack includes a pack-to-tool interface region configured to provide controlled mechanical insertion, positional stability, and high-current electrical coupling when the battery' pack is installed in the power tool 10. This interface region is located adjacent a tool -facing end of the battery pack housing, such as the upper end 520 of batteryP-WO-TN-2025-0009 / / 1076-0022WO Patent pack 500 or baten-pack 1800, and is configured to engage corresponding interface surfaces and electrical terminals within a batery receptacle cavity of the handle assembly 12.[000462] In some embodiments, the pack-to-tool interface region includes one or more constraining surfaces that cooperate with complementary surfaces of the power tool 10 to locate the batery pack relative to the tool during insertion and use. As used herein, constraining surface area may refer to the total surface area of such housing surfaces that mechanically locate the batery pack within the tool. In representative embodiments, the constraining surface area is approximately 6,300 mm2, and may fall within a range from approximately 5,000 mm2to approximately 7,500 mm2.[000463] The battery pack is configured to be inserted into the power tool along an insertion axis (e.g., insertion axis 521). In some embodiments, insertion distance refers to a linear distance measured along the insertion axis of the tool interface. A maximum insertion distance of approximately 64.6 mm and a minimum insertion distance of approximately 40.5 mm define acceptable axial engagement ranges that contribute to insertion rigidity and mechanical stability. As shown in FIG. 2, insertion distance 199 may be measured along the batery insertion axis 21 between the batery pack 1800 and the handle assembly 12.[000464] As used herein, minimum and maximum insertion distance values may each be characterized by independent nominal values associated with a given embodiment, while the broader minimum and maximum ranges reflect compatibility across different tool models, handle geometries, or batery-pack variants. Accordingly, the minimum insertion distance and maximum insertion distance are not required to define a single contiguous engagement window within one embodiment.[000465] In some embodiments, the battery-pack includes one or more power terminals positioned at the tool-facing end of the pack housing. Each power terminal may have an axial terminal length of approximately 22 mm, with terminal lengths ranging from approximately 8 mm to approximately 75 mm. Such terminal lengths provide sufficient engagement overlap with corresponding tool-side terminals while accommodating manufacturing tolerances and insertion misalignment.[000466] In some embodiments, the power terminals have a terminal effective diameter of approximately 4.5 mm, with diameters ranging from approximately 2 mm to approximately 6 mm. In combination with this diameter, a terminal contact surface area of approximately 320 mm2may be provided, with contact surface areas ranging from approximately 50 mm2to approximately 1.413 mm2, depending on terminal geometry and contact design.[000467] As used herein, “terminal effective diameter” may refer to a contact or current-carrying diameter, while “terminal outer diameter’ may include insulation, coatings, or non-conductive structural features. The conductive cross-sectional area may correspond to a current-carrying region of the terminal and is not required to correspond directly to either the effective diameter or the outer diameter.[000468] In some embodiments, the power terminals are configured to support a maximum continuous current of approximately 90 amps, with current-handling capability ranging fromP-WO-TN-2025-0009 / / 1076-0022WO Patent approximately 30 amps to approximately 195 amps. As used herein, maximum terminal current may refer to a continuous current delivery rating. Terminal resistance, when referenced, corresponds to a measured resistance value of the assembled terminal and associated conductors.[000469] In some embodiments, the power terminals have a conductive cross-sectional area of approximately 19.6 mm2, with cross-sectional areas ranging from approximately 4.9 mm2to approximately 33.2 mm2. This cross-sectional area contributes to current-carrying capability and resistance control and may be measured through a region constrained by a cell axis keepout area within the battery7pack. Terminal resistance may be measured as part of a completed assembly and, in some embodiments, is characterized as a measured value rather than a predefined design limit.[000470] In some embodiments, a distance between a conductive surface of a battery cell and a corresponding power terminal is approximately 2.65 mm, with such distances ranging from approximately 1.5 mm to approximately 6 mm. This distance may be measured edge-to-edge between a cell conductive surface and a terminal connection to the cell and may represent a minimum conductor spacing.[000471] In some embodiments, the power terminals have an outer diameter of approximately 5 mm, with outer diameters ranging from approximately 2.5 mm to approximately 6.5 mm, depending on terminal construction and insulation requirements.[000472] In some embodiments, the pack-to-tool interface region has an overall interface girth of approximately 85.9 mm, with girths ranging from approximately 78 mm to approximately 105 mm, as measured around a perimeter of the interface region. This interface girth contributes to grip continuity, insertion stability, and compatibility' with handle geometries of the power tool 10.[000473] Representative examples of these interface geometry characteristics are summarized in Table 1.Table 1: Battery Pack-to-Tool Interface GeometryP-WO-TN-2025-0009 / / 1076-0022WO Patent Representative Battery Pack Geometry — 2-2-1 Configuration[000474] In some embodiments, the battery pack includes a 2-2-1 battery cell configuration, such as battery pack 1800. In this configuration, battery cells are arranged along an insertion axis of the battery pack such that portions of the pack are received within the handle assembly 12 of the power tool 10, while other portions extend outward to define a user-grippable portion of the battery' pack.[000475] In some embodiments, the battery' pack has an overall pack length measured along the insertion axis of approximately 105 mm, with pack lengths ranging from approximately 102 mm to approximately 115 mm. This length permits sufficient axial engagement with the power tool 10 while allowing a portion of the battery' pack to extend beyond the tool housing to function as an auxiliary grip.[000476] In some embodiments, the battery pack defines a pack depth measured in a front-to-back direction of approximately 54.4 mm, with depths ranging from approximately 43 mm to approximately 65 mm, and a pack width of approximately 44.2 mm, with widths ranging from approximately 28 mm to approximately 55 mm. Together, the pack depth and width contribute to ergonomic compatibility with the handle assembly 12 and internal clearance for battery cells and interconnection components.[000477] In some embodiments, the battery pack defines an overall pack girth measured around a perimeter of the pack housing at a grip portion of approximately 141.2 mm, with girths extending up to approximately 220 mm in certain embodiments. The pack girth may be selected to provide a comfortable grip profile for a user while maintaining continuity with the geometry of the power tool handle.[000478] In some embodiments, the battery' pack defines a maximum pack cross-sectional area measured perpendicular to the insertion axis at a region of maximum external girth of the battery' pack housing, which in representative embodiments is approximately 800 mm2. This maximum pack cross-sectional area characterizes the external volumetric envelope of the battery pack and may be distinct from internal cell or core pack cross-sections. In representative embodiments, a handle interface cross-sectional area of approximately 1,544 mm2is provided to cooperate with a corresponding cross-section of the handle assembly 12 of the pow er tool 10.[000479] In some embodiments, the battery pack defines a total battery pack displacement volume of approximately 142 cm3, representing the volume occupied by the pack housing and internal components. A portion of this volume may correspond to a pack handle-associated displacement volume of approximately 56.85 cm3, which includes material associated with a bottom cap and grip portion of the battery’ pack. In some embodiments, an internal air displacement volume of approximately 5.25 cm3is provided within the battery pack housing, with air displacement volumes ranging from approximately 4 cm3to approximately 10 cm3, corresponding to non-component cavities within the pack housing.[000480] As used herein, ‘ displacement volume’ may refer to a volume occupied by a component or assembly, including a housing and enclosed components, and may be determined by measurement, CAD-derived volume, or other volumetric determination methods.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000481] As used herein, 'air displacement volume’ may refer to internal void volume within a battery pack that is not occupied by functional components (e.g.. cells, conductors, carriers) and may include cavities formed by housing geometry, assembly clearances, and non-component spaces.[000482] FIG. 25C is a schematic representation of volumetric regions of the battery pack 1800 and is not drawn to scale. The figure is provided to illustrate relative volumetric relationships among components and internal regions of the battery pack rather than precise geometric proportions.[000483] In FIG. 25C, an outer boundary' 2510 generally represents an exterior envelope of the battery pack housing. A volume bounded by the outer boundary 2510 corresponds to a battery pack displacement volume, which includes the volume occupied by the battery pack housing and internal contents.[000484] An inner boundary 2512 generally represents an internally formed surface of the battery pack housing. A volume bounded by the inner boundary 2512 corresponds to an interior battery pack housing cavity volume, which defines an internal cavity region configured to receive the plurality of battery cells and other functional battery pack components, sometimes referred to as a core pack.[000485] FIG. 25C schematically illustrates a plurality of battery cells 1845 positioned within the interior battery pack housing cavity volume, such that the aggregate volume occupied by the battery cells corresponds to a total battery cell displacement volume. FIG. 25C further illustrates one or more non-battery cell regions 2514 representing a non-battery cell core pack volume occupied by functional battery pack components other than the battery7cells 1845, including electrical interconnections (battery' straps), terminals, carriers (cell holder), circuit boards, and associated electronics. FIG. 25C also illustrates an internal air region 2516 representing a void volume within the battery pack housing cavity7volume that is not occupied by functional components, such that the region 2516 corresponds to an internal air displacement volume. Together, the total battery' cell displacement volume, the non-battery cell core pack volume represented by region 2514, and the internal air displacement volume correspond to the interior battery pack housing cavity volume. As such, a ratio of the core pack volume (the total battery7cell displacement volume plus the non-battery cell core pack volume) to the interior battery pack housing cavity volume may be in a range of approximately 0.90 to approximately 0.98.[000486] In FIG. 25C, a section plane 2518 is illustrated extending transverse to the insertion axis 1821. The section plane 2518 represents a reference plane at which a transverse cross-sectional area of the battery pack 1800 may be evaluated. As used herein, battery pack cross-sectional area may refer to an area bounded by an exterior envelope of the battery pack housing (e.g., outer boundary 2510) in a plane transverse to the insertion axis 1821, such as at the section plane 2518. In some embodiments, a maximum battery7pack cross-sectional area corresponds to a largest such transverse area of the exterior envelope taken across a plurality7of planes along the insertion axis 1821.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000487] FIG. 25D illustrates a schematic representation of a handle-associated volumetric region of the battery pack 1800 when installed in a power tool. The figure is schematic in nature, is not drawn to scale, and is provided to illustrate relative volumetric relationships rather than precise geometric proportions. As shown, the battery pack 1800 includes a first housing portion 1804 configured to be received within a battery receptacle cavity of the handle assembly and a second housing portion 1806 configured to remain external to the handle assembly and to cooperate with the handle assembly to form a composite grip region.[000488] A grip registration plane 1900 is illustrated extending transverse to the battery insertion axis and defining a reference boundary associated with a user-grippable handle region of the battery pack. The grip registration plane 1900 is positioned to distinguish portions of the battery pack housing that are associated with handle-related structural material from portions of the battery pack housing associated with a tool-facing interface region.[000489] As used herein, handle displacement volume may refer to a volume defined by an exterior envelope of a handle assembly of the power tool located on a handle-associated side of a grip registration plane 1900. The handle displacement volume is a geometric characterization of the power tool handle and is defined independently of an installation state of a removable battery pack.[000490] As further illustrated in FIG. 25D, a transverse section plane 2528 is shown extending across the handle-associated region on the handle-associated side of the grip registration plane 1900. As used herein, a handle interface cross-sectional area may refer to an area of the exterior envelope 2530 of the handle assembly measured in a plane transverse to the insertion axis at the section plane 2528. The handle interface cross-sectional area characterizes an external geometric envelope of the handle region and is independent of internal cavity geometry, wall thickness, or the presence or absence of a battery pack.[000491] In some embodiments, the battery pack mass may be measured for a completed assembly and may vary depending on cell selection, housing material, and interconnection design.[000492] Representative examples of the battery pack geometry for a 2-2-1 configuration are summarized in Table 2.Table 2: Batery Pack Geometry — 2-2-1 ConfigurationP-WO-TN-2025-0009 / / 1076-0022WO Patent Internal air displacement volume 5.25Representative Battery Cell Characteristics — 18350 Cells[000493] In some embodiments, the battery pack includes a plurality of cylindrical battery cells having an 18350 form factor, such as the battery cells incorporated within battery pack 1800. The characteristics of such battery cells contribute to overall pack geometry, energy density, and electrical performance.[000494] In some embodiments, each battery cell defines a single-cell volume of approximately 8.9 cm3, with cell volumes ranging from approximately 7.7 cm3to approximately 10.2 cm3. The cell volume corresponds to the volumetric envelope of the cylindrical cell and influences packing density within the battery' pack housing.[000495] In some embodiments, each battery cell has an axial length of approximately 35 mm, with cell lengths ranging from approximately 31 mm to approximately 39 mm, and a nominal cell diameter of approximately 18 mm. The cell diameter may be substantially constant across embodiments, while cell length may vary depending on cell construction and internal capacity.[000496] In some embodiments, the mass of each battery cell may be measured as part of a representative sample set and may vary depending on cell chemistry and construction.[000497] In some embodiments, the battery cells are characterized by an internal electrical impedance. Such impedance may be measured within a representative sample lot and may influence power delivery capability, thermal behavior, and voltage drop during high-current operation.[000498] In some embodiments, each battery cell has a nominal electrical capacity' of approximately 1.5 ampere-hours, with capacities ranging from approximately 0.8 ampere-hours to approximately 2.1 ampere-hours. In some embodiments, assuming a battery' pack voltage of approximately 20 volts, the battery' pack may have an energy capacity' of approximately 30 watt-hours, with energy capacities ranging from approximately 16 watt-hours to approximately' 42 watt-hours, depending on cell chemistry', cell count, and configuration.[000499] Representative examples of battery' cell characteristics for 1 350 cells are summarized in Table 3.Table 3: Battery Cell Characteristics and PackEnergy — 18350 CellsP-WO-TN-2025-0009 / / 1076-0022WO PatentRepresentative Core Pack Geometry and Interconnection — 2-2-1 Configuration [000500] In some embodiments, the battery pack includes an internal core pack that supports a plurality of battery cells and associated electrical interconnections, such as within battery pack 1800. The core pack defines a structural and electrical subassembly that houses the battery' cells, the printed circuit board and associated / attached components, electrical conductors, terminals, and interconnection features that collectively deliver electrical power from the cells to the pack-to-tool interface region.[000501] In some embodiments, the core pack defines an overall assembly length measured along the insertion axis of approximately 95.2 mm, with assembly lengths ranging from approximately 92 mm to approximately 110 mm. This assembly length reflects the axial extent of the cell grouping and interconnection structure positioned within the handle assembly 12 of the power tool 10.[000502] In some embodiments, the core pack defines a cross-sectional area measured perpendicular to the insertion axis of approximately 777 mm2, with cross-sectional areas ranging from approximately 750 mm2to approximately 950 mm2. This cross-sectional area corresponds to an upper region of the core pack positioned within the handle assembly of the power tool and accommodates both the battery cells and the associated interconnection components.[000503] In some embodiments, the core pack defines a total core pack displacement volume of approximately 79.95 cm3, with displacement volumes ranging from approximately 72 cm3to approximately 100 cm3. This volume may include the combined volume of the batten' cells, the printed circuit board and associated / attached components, electrical terminals, carrier structures, and interconnection components that collectively form the functional battery' assembly.[000504] In some embodiments, the total displacement volume of the battery cells within the battery pack is approximately 44.5 cm3, with cell displacement volumes ranging from approximately 42 cm3to approximately 51 cm3. In some embodiments, a maximum cell cross-sectional area of approximately 630 mm2is defined at a location of maximum girth of the complete core pack, with such cross-sectional areas ranging from approximately 540 mm2to approximately 720 mm2. This maximum cross-sectional area may differ from the cross-sectional area defined by the uppermost cells alone and may correspond to a region including both cells and interconnection features.[000505] In some embodiments, the core pack is characterized by an electrical impedance that may be measured at a representative state of charge, such as a full state of charge, and may van' depending on cell selection, interconnection design, and conductor geometry.[000506] In some embodiments, the core pack includes one or more cell connectors that electrically couple adjacent battery' cells. Each cell connector may define a connector volume of approximately 0.649 cm3, with connector volumes ranging from approximately 0.5 cm3to approximately 1.1 cm3, and a connector mass of approximately 5.776 g, with connector massesP-WO-TN-2025-0009 / / 1076-0022WO Patent ranging from approximately 4.45 g to approximately 9.79 g. These connector characteristics influence both electrical resistance and overall mass of the battery pack.[000507] As used herein, “weld-to-weld spacing” may refer to a center-to-center spacing between immediately adjacent welds along a given electrical interconnection path, whereas ‘“total weld length” may refer to an aggregate linear length measured across multiple welds along a conductive interconnection feature. “Average weld spacing” may refer to an average spacing calculated across non-uniform weld patterns or across multiple interconnection segments, and “weld spacing deviation” may reflect variation across weld groups or across distinct interconnection paths rather than deviation from a single mean spacing. Accordingly, these weld metrics are not required to be directly comparable or constrained to similar magnitudes.[000508] As used herein, the terms “length” and “distance,” when referring to welds or interconnection features, may be used interchangeably to denote a linear measurement along or between conductive features, unless otherwise specified.[000509] In some embodiments, adjacent battery cells are electrically coupled by welds or similar permanent electrical joints. In representative embodiments, a weld-to-weld spacing of approximately 4.4 mm is provided, with weld spacings ranging from approximately 3 mm to approximately 5.7 mm. In some embodiments, a total weld length across a plurality’ of welds is approximately 20.2 mm, with total weld lengths ranging from approximately 20 mm to approximately 30 mm.[000510] In some embodiments, an average weld spacing of approximately 5.05 mm is provided, with average weld spacings ranging from approximately 4.8 mm to approximately 6.2 mm. In some embodiments, a weld spacing deviation of approximately 1.3 mm may be observed, with deviations extending down to approximately 0 mm in certain assemblies. Such weld spacing characteristics may reflect manufacturing tolerances and interconnection consistency.[000511] Representative examples of core pack geometry and interconnection characteristics for a 2-2-1 battery pack configuration are summarized in Table 4.Table 4: Core Pack Geometry' and Interconnection — 2-2-1 ConfigurationP-WO-TN-2025-0009 / / 1076-0022WO Patent mmRepresentative Electrical Power Capability — 2-2-1 Configuration[000512] In some embodiments, a batten- pack having a 2-2-1 battery cell configuration, such as battery pack 1800, is configured to deliver electrical power to the power tool 10 across a range of operating conditions, including both continuous operation and short-duration high-load events.[000513] In some embodiments, the battery pack may be capable of delivering a continuous electrical current of approximately 25 amperes, with continuous current capability ranging from approximately 20 amperes to approximately 32 amperes, depending on operating conditions, state of charge, and thermal environment. Such continuous current capability7supports sustained operation of the power tool during normal use.[000514] In some embodiments, the battery pack may be capable of delivering a pulsed electrical current of approximately 40 amperes, with pulsed current capability ranging from approximately 30 amperes to approximately 55 amperes for short durations. Such pulsed current delivery may support transient high-load events, such as tool startup or momentary torque increases.[000515] In some embodiments, assuming a battery voltage of approximately 20 volts, the battery pack may be configured to deliver a continuous electrical power of approximately 450 watts, with continuous power deliver}7ranging from approximately 400 watts to approximately 600 watts. In some embodiments, the battery pack may be further capable of delivering pulsed electrical power of approximately 700 watts, with pulsed power deliver}7ranging from approximately 525 watts to approximately 960 watts for short durations.[000516] The electrical power capability described herein may be influenced by cell selection, interconnection design, thermal conditions, and state of charge, and may vary7across different embodiments and operating environments.[000517] Representative examples of electrical power capability for a 2-2-1 batter}' pack configuration are summarized in Table 5.Table 5: Electrical Power Capability — 2-2-1ConfigurationRepresentative Battery Pack Geometry — 2-Over-3 Configuration[000518] In some embodiments, the battery pack includes a 2-over-3 battery cell configuration, such as battery pack 500. In this configuration, a plurality of battery cells are arranged such that a greater number of cells are stacked along a portion of the insertion axis, resulting in an increased pack length and overall energy capacity relative to other configurations.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000519] In some embodiments, the battery pack has an overall pack length measured along the insertion axis of approximately 149 mm, with pack lengths extending up to approximately 160 mm in certain embodiments. This increased length accommodates the additional battery cells of the 2-over-3 configuration while maintaining compatibility with the handle assembly 12 of the power tool 10.[000520] In some embodiments, the battery pack defines a pack depth of approximately 54.4 mm, with depths ranging from approximately 43 mm to approximately 65 mm, and a pack width of approximately 44.2 mm, with widths ranging from approximately 38 mm to approximately 55 mm. These dimensions allow the battery' pack to integrate with the handle geometry of the power tool 10 while providing internal clearance for the additional cells and interconnection components.[000521] In some embodiments, the battery pack defines an overall pack girth of approximately 141.2 mm, measured around a perimeter of the pack housing at a grip portion of the battery pack. The pack girth may be selected to provide a comfortable grip profile for a user and to maintain continuity with adjacent handle surfaces of the power tool.[000522] In some embodiments, the battery pack defines a pack cross-sectional area measured perpendicular to the insertion axis of approximately 1,757 mm2, corresponding to a region of maximum cross-section of the pack housing. In some embodiments, a handle interface cross-sectional area of approximately 1,544 mm2is provided to cooperate with a corresponding crosssection of the handle assembly 12 of the power tool 10.[000523] In some embodiments, the battery' pack defines a total battery pack displacement volume of approximately 199.25 cm3, reflecting the volume occupied by the pack housing and internal components. In some embodiments, a handle displacement volume of approximately 75.9 cm3is provided, corresponding to material associated with a grip portion and bottom cap of the battery pack. In some embodiments, an internal air displacement volume of approximately 3.2 cm3is defined within the battery pack housing, corresponding to non-component cavities.[000524] Representative examples of battery pack geometry for a 2-over-3 configuration are summarized in Table 6.Table 6: Baten' Pack Geometry — 2-Over-3 ConfigurationRepresentative Battery Cell Characteristics — 18650 CellsP-WO-TN-2025-0009 / / 1076-0022WO Patent [000525] In some embodiments, the battery pack includes a plurality of cylindrical battery cells having an 18650 form factor, such as the battery cells incorporated within battery pack 500. The characteristics of such battery cells contribute to the overall energy capacity, power delivery capability, and physical dimensions of the battery pack.[000526] In some embodiments, each battery cell defines a single-cell volume of approximately 16.53 cm3, with cell volumes ranging from approximately 15 cm3to approximately 19 cm3. The increased cell volume relative to smaller cell formats accommodates higher energy storage within each cell.[000527] In some embodiments, each battery' cell has an axial length of approximately 65.2 mm, with cell lengths ranging from approximately 64 mm to approximately 69 mm, and a nominal cell diameter of approximately 18 mm, with diameters ranging from approximately 17.8 mm to approximately 18.9 mm. These dimensional characteristics influence the axial extent and cross-sectional envelope of the battery pack.[000528] In some embodiments, each battery cell has a mass of approximately 50 grams, with cell masses ranging from approximately 42 grams to approximately 65 grams, depending on cell chemistry and construction.[000529] In some embodiments, the battery cells are characterized by an internal electrical impedance of approximately 3.08 milliohms, with impedances ranging from approximately 2.5 milliohms to approximately 4 milliohms, as measured within a representative sample lot. The internal impedance influences voltage drop, thermal behavior, and high-current performance.[000530] In some embodiments, each battery cell has a nominal electrical capacity' of approximately 3 ampere-hours, with capacities ranging from approximately 1.5 ampere-hours to approximately 4.5 ampere-hours. In some embodiments, assuming a battery cell voltage of approximately 4 volts and a battery pack voltage of approximately 20 volts, the battery' pack may have an energy capacity7of approximately 60 watt-hours, with energy capacities ranging from approximately 30 watt-hours to approximately 90 watt-hours, depending on cell chemistry, cell count, and configuration.[000531] Representative examples of battery cell characteristics for 18650 cells are summarized in Table 7.Table 7: Battery Cell Characteristics and PackEnergy — 18650 CellsP-WO-TN-2025-0009 / / 1076-0022WO PatentRepresentative Core Pack Geometry and Electrical Interconnection — 2-Over-3 Configuration[000532] In some embodiments, a battery pack having a 2-over-3 battery cell configuration, such as battery pack 500, includes an internal core pack that supports a plurality of battery' cells and associated electrical interconnections. The core pack defines a structural and electrical subassembly that delivers electrical power from the battery' cells to the pack-to-tool interface region described herein.[000533] In some embodiments, the core pack defines a cross-sectional area measured perpendicular to the insertion axis of approximately 1,400 mm2, with cross-sectional areas ranging from approximately 1,220 mm2to approximately 1,550 mm2. This cross-sectional area corresponds to an upper region of the core pack positioned within the handle assembly 12 of the power tool 10 and accommodates the increased number of battery cells and interconnection components associated with the 2-over-3 configuration.[000534] In some embodiments, the core pack defines a total displacement volume of approximately 107.89 cm3, with displacement volumes ranging from approximately 98.1 cm3to approximately 130 cm3. This displacement volume represents the combined volume of the battery¬ cells, electrical connectors, terminals, and carrier structures that collectively form the functional battery assembly.[000535] In some embodiments, the total displacement volume of the battery cells within the battery- pack is approximately 82.65 cm3, with cell displacement volumes ranging from approximately 73 cm3to approximately 100 cm3. In some embodiments, a maximum cell cross-sectional area of approximately 819 mm2is defined at a region of maximum girth of the complete core pack, with such cross-sectional areas ranging from approximately 730 mm2to approximately 920 mm2.[000536] In some embodiments, the core pack is characterized by an electrical impedance of approximately 16.6 milliohms, with impedance values ranging from approximately 13.1 milliohms to approximately 20 milliohms, as measured at a representative state of charge. The electrical impedance reflects combined resistive effects of the battery cells and electrical interconnections.[000537] In some embodiments, the core pack includes a plurality of cell connectors configured to electrically couple adjacent battery cells. Each cell connector may define a connector volume of approximately 0.519 cm3, with connector volumes ranging from approximately 0.45 cm3to approximately 1.0 cm3, and a connector mass of approximately- 4.619 g. with connector masses ranging from approximately- 4.005 g to approximately 8.9 g.[000538] In some embodiments, adjacent battery cells are electrically coupled by welds or similar permanent electrical joints. In representative embodiments, a weld-to-weld spacing of approximately 4.4 mm is provided, with weld spacings ranging from approximately 4.1 mm to approximately 75 mm, depending on cell layout and interconnection routing. In someP-WO-TN-2025-0009 / / 1076-0022WO Patent embodiments, a total weld length of approximately 87.6 mm is provided across a plurality of welds, with total weld lengths ranging from approximately 80 mm to approximately 110 mm.[000539] In some embodiments, an average weld spacing of approximately 21.9 mm is provided, with average weld spacings ranging from approximately 18 mm to approximately 30 mm. In some embodiments, a weld spacing deviation of approximately 26.55 mm may be observed, with deviations ranging from approximately 20 mm to approximately 30 mm, reflecting manufacturing tolerances and interconnection path variability.[000540] Representative examples of core pack geometry' and electrical interconnection characteristics for a 2-over-3 battery' pack configuration are summarized in Table 8.Table 8: Core Pack Geometry and Electrical Interconnection — 2-Over-3 ConfigurationRepresentative Electrical Power Capability — 2-Over-3 Configuration[000541] In some embodiments, a battery pack having a 2-over-3 battery cell configuration, such as battery pack 500, is configured to deliver increased electrical current and power relative to other battery pack configurations described herein. Such increased electrical capability supports higher-power operation of the power tool 10 and accommodates more demanding load conditions.[000542] In some embodiments, the battery pack may be capable of delivering a continuous electrical current of approximately 56 amperes, with continuous current capability ranging from approximately 30 amperes to approximately 70 amperes, depending on operating conditions, state of charge, and thermal environment. This continuous current capability' supports sustained high-load operation of the power tool.[000543] In some embodiments, the battery pack may be capable of delivering a pulsed electrical current of approximately 140 amperes, with pulsed current capability ranging from approximately 80 amperes to approximately 170 amperes for short durations. Such pulsed current delivery may support transient events such as tool startup, momentary torque spikes, or other short-duration high-demand conditions.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000544] In some embodiments, assuming a battery pack voltage of approximately 20 volts, the battery pack may be configured to deliver a continuous electrical power of approximately 1,021 watts, with continuous power deliver}’ ranging from approximately 400 watts to approximately 1.250 watts. In some embodiments, the battery pack is further capable of delivering pulsed electrical power of approximately 2,210 watts, with pulsed power delivery' ranging from approximately 1,200 watts to approximately 2,600 watts for short durations.[000545] The electrical power capability described herein may be influenced by cell selection, core pack geometry’, electrical interconnection design, thermal conditions, and state of charge, and may vary’ across different embodiments and operating environments.[000546] Representative examples of electrical power capability for a 2-over-3 battery pack configuration are summarized in Table 9.Table 9: Electrical Power Capability — 2-Over-3ConfigurationRepresentative Volumetric Packaging Efficiency Ratios — 2-2-1 Configuration [000547] In some embodiments, a battery pack as described herein is further characterized by volumetric packaging efficiency metrics that relate the volume of active battery cells to the volume of surrounding structural and interconnection components. Such volumetric ratios provide a measure of how efficiently battery cell volume is packaged within a given battery' pack architecture and are largely independent of battery chemistry, cell impedance, or electrical performance characteristics.[000548] In some embodiments, the volumetric packaging efficiency ratios described below are derived from previously disclosed displacement volumes associated with battery’ pack 1800, including total battery cell displacement volume, total core pack displacement volume, and overall battery pack displacement volume, as described herein. In representative embodiments, the total battery pack displacement volume is in a range of approximately 135 cubic centimeters to approximately 150 cubic centimeters, such as a nominal value of approximately 142 cubic centimeters.[000549] In some embodiments, the volumetric ratio values summarized in Tables 10-16 are calculated using nominal battery pack displacement volumes (e.g., approximately 142 cubic centimeters for a 2-2-1 configuration and approximately 199.25 cubic centimeters for a 2-over-3 configuration), while permitting one or more of the numerator quantities (e.g., total battery cell displacement volume or core pack displacement volume) to vary within the ranges disclosed herein. In other embodiments, such volumetric ratios may be calculated using minimum, maximum, or intermediate values of both numerator and denominator quantities, such that theP-WO-TN-2025-0009 / / 1076-0022WO Patent resulting ratio ranges may differ from those expressly tabulated. Accordingly, the ratio values provided herein are exemplary and non-limiting and may be recalculated across full disclosed dimensional and volumetric ranges without departing from the scope of the disclosure. The ratio ranges described herein are not intended to require simultaneous extrema of the underlying parameters unless expressly stated.[000550] In some embodiments, the total battery' cell displacement volume corresponds to the combined displacement volume of a plurality of battery' cells housed within the battery pack. In representative 2-2-1 embodiments, the total battery' cell displacement volume is in a range of approximately 42 cubic centimeters to approximately 47 cubic centimeters, such as a nominal value of approximately 44.5 cubic centimeters, as derived from the sum of individual cell volumes disclosed herein. In other embodiments, including higher-capacity7configurations, the total battery cell displacement volume may be in a range of approximately 78 cubic centimeters to approximately 87 cubic centimeters in representative embodiments, and extending beyond that range in further embodiments.[000551] In some embodiments, each of the plurality of battery cells has an individual cell displacement volume selected from a range of approximately 7.7 cubic centimeters to approximately 10.2 cubic centimeters, corresponding to smaller-format cylindrical cells, or from a range of approximately 15 cubic centimeters to approximately 19 cubic centimeters, corresponding to larger-formal cylindrical cells. The selection of cell volume contributes directly to the total battery' cell displacement volume of the battery' pack.[000552] In some embodiments, a ratio of total battery cell displacement volume to total core pack displacement volume characterizes the fraction of the core pack occupied by battery' cells relative to a printed circuit board and associated / attached components, structural carriers, electrical interconnections, terminals, and other non-cell components. In representative embodiments, this ratio has a nominal value of approximately 0.56, with values ranging from approximately 0.42 to approximately 0.71, indicating that a majority of the core pack volume is occupied by battery cells. Unless otherwise noted, ratio values may be computed using the nominal and range values of the corresponding underlying volumes.[000553] In some embodiments, a ratio of total battery cell displacement volume to overall battery pack displacement volume characterizes the fraction of the entire battery pack volume devoted to energy -storing battery cells. In representative embodiments, this ratio has a nominal value of approximately 0.31, with values ranging from approximately 0.30 to approximately 0.36. In further embodiments encompassing multiple disclosed configurations, the ratio of total battery¬ cell displacement volume to total battery pack displacement volume may fall within a broader range of approximately 0.285 to approximately 0.515, including subranges between approximately 0.30 and approximately 0.50.[000554] In some embodiments, a ratio of total core pack displacement volume to overall battery' pack displacement volume characterizes the fraction of the battery' pack volume occupied by functional battery7components, including battery7cells, printed circuit boards and associated / attached components, electrical connectors, terminals, carriers, and interconnectionP-WO-TN-2025-0009 / / 1076-0022WO Patent structures. In representative embodiments, this ratio has a nominal value of approximately 0.56, with values ranging from approximately 0.51 to approximately 0.70.[000555] The volumetric packaging efficiency ratios described herein provide a geometry-based characterization of battery pack compactness and packaging efficiency that remains applicable as battery cell technology evolves. Because these ratios are derived from physical volumes rather than electrical output alone, they provide a robust framework for comparing different battery pack architectures and for constraining future designs that seek to increase performance without increasing overall size.[000556] Representative examples of volumetric packaging efficiency ratios for a 2-2-1 battery pack configuration are summarized in Table 10.Table 10: Volumetric Packaging Efficiency Ratios — 2-2-1 ConfigurationRepresentative Volumetric Packaging Efficiency Ratios — 2-Over-3 Configuration [000557] In some embodiments, a battery pack having a 2-over-3 battery cell configuration, such as battery' pack 500, is characterized by volumetric packaging efficiency ratios derived from the relative volumes of battery' cells, core pack components, and the overall battery pack housing. In representative embodiments, the total battery pack displacement volume is greater than approximately 190 cubic centimeters, and the total battery' cell displacement volume is in a range of approximately 78 cubic centimeters to approximately 87 cubic centimeters. In some embodiments, the calculation basis for core-pack-related displacement volumes may differ from the calculation basis for aggregate cell displacement volumes, as described below.[000558] In some embodiments, a ratio of total battery cell displacement volume to total core pack displacement volume characterizes the extent to which the core pack volume is occupied by battery cells relative to interconnection structures and support components. In representative embodiments, this ratio has a nominal value of approximately 0.77, with values ranging from approximately 0.56 to approximately 1.02.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000559] In some embodiments, volumetnc ratios involving core pack displacement volume may exceed unity due to measurement methodology, tolerance accumulation, or differences between nominal CAD-derived volumes and as-built measured volumes. For example, in certain embodiments, total battery’ cell displacement volume may be determined based on aggregate individual cell envelopes, while core pack displacement volume may be determined based on a functional or bounded subassembly volume that excludes localized clearances, coatings, or nonload-bearing features. Accordingly, ratio values greater than 1.0 do not require that battery cell volume physically exceed core pack volume within a single embodiment.[000560] In some embodiments, a ratio of total battery cell displacement volume to overall battery pack displacement volume characterizes the fraction of the battery’ pack volume devoted to battery7cells. In representative embodiments, this ratio has a nominal value of approximately 0.42, with values ranging from approximately’ 0.37 to approximately 0.50, and in some embodiments extending upward toward approximately 0.515.[000561] In some embodiments, a ratio of total core pack displacement volume to overall battery pack displacement volume characterizes the fraction of the battery pack volume occupied by functional battery components. In representative embodiments, this ratio has a nominal value of approximately 0.54, with values ranging from approximately 0.49 to approximately 0.65.[000562] Representative examples of volumetric packaging efficiency ratios for a 2-over-3 battery pack configuration are summarized in Table 11.Table 11: Volumetric Packaging Efficiency Ratios (2-0 ver- 3 Configuration)[000563] The ratio ranges described herein reflect variation across disclosed embodiments, configurations, and parameters, and are not intended to require that all minimum and maximum values be achieved simultaneously within a single embodiment.Representative Cell Volume-to-Handle Geometry Ratios[000564] In some embodiments, a battery pack as described herein is further characterized by ratios that relate the volume of energy-storing battery' cells to geometric characteristics of a handleP-WO-TN-2025-0009 / / 1076-0022WO Patent interface region of the power tool 10. Such ratios characterize the extent to which battery cell volume is integrated within ergonomically constrained regions of the tool and provide a systemlevel measure of packaging efficiency that incorporates both battery pack design and tool handle geometry.[000565] In some embodiments, a ratio of total battery cell displacement volume to a handle interface cross-sectional area characterizes the amount of energy storage integrated within a given handle envelope. The handle interface cross-sectional area may correspond to a region of the battery pack configured to cooperate with the handle assembly 12 of the power tool 10 and may be substantially constrained by ergonomic considerations.[000566] In representative embodiments having a 2-2-1 battery cell configuration, such as battery pack 1800, the ratio of total battery cell displacement volume to handle interface cross-sectional area has a nominal value of approximately 0.0288 cm3 / mm2, with values ranging from approximately 0.0272 cm’ / mm2to approximately 0.033 cm’ / mm2. These values reflect the integration of battery cell volume within a compact handle interface geometry.[000567] In representative embodiments having a 2-over-3 battery cell configuration, such as battery pack 500, the ratio of total battery cell displacement volume to handle interface cross-sectional area has a nominal value of approximately 0.0535 cm3 / mm2, with values ranging from approximately 0.0473 cm’ / mm2to approximately 0.0648 cm’ / mm2. These values reflect increased energy storage integrated within substantially the same handle interface geometry’.[000568] The cell volume-to-handle geometry ratios described herein provide an ergonomic and geometry-based characterization of battery pack integration that constrains achievable energy storage without increasing handle size. Because these ratios relate energy' storage directly to handle geometry', they remain applicable as battery’ cell technology’ evolves and provide a robust framework for comparing different battery' pack and tool architectures.[000569] Representative examples of cell volume-to-handle geometry ratios are summarized in Table 12.Table 12: Cell Volume-to-Handle Geometry RatiosP-WO-TN-2025-0009 / / 1076-0022WO Patent Representative Power Density Ratios — 2-2-1 Configuration[000570] In some embodiments, a battery pack as described herein is further characterized by power density ratios that relate electrical power delivery’ capability to the physical size of the battery pack. Such ratios normalize electrical performance by geometric size and provide a comparative measure of performance efficiency that is independent of absolute battery' pack dimensions.[000571] In some embodiments, a ratio of continuous electrical power to total battery' pack displacement volume characterizes sustained power delivery' capability' normalized by pack size. In representative embodiments having a 2-2-1 battery' cell configuration, assuming a battery' pack voltage of approximately 20 volts, such as battery pack 1800, this ratio has a nominal value of approximately 3.17 watts per cubic centimeter, yvith values ranging from approximately' 2.82 watts per cubic centimeter to approximately 4.23 watts per cubic centimeter. This ratio reflects the ability of the battery pack to support continuous operation within a compact volumetric envelope.[000572] In some embodiments, a ratio of pulsed electrical power to total battery' pack displacement volume characterizes short-duration power delivery capability normalized by pack size. In representative embodiments, assuming a battery’ pack voltage of approximately 20 volts, this ratio has a nominal value of approximately 4.93 watts per cubic centimeter, with values ranging from approximately 3.7 watts per cubic centimeter to approximately 6.76 yvatts per cubic centimeter. Such pulsed power density may support transient high-load events, such as tool startup or brief increases in torque demand.[000573] The power density ratios described herein provide a size-normalized characterization of battery' pack performance that remains applicable across different battery' chemistries, cell constructions, and electrical architectures. By normalizing power delivery' by pack volume, these ratios enable meaningful comparison of different battery' pack configurations w'ithout reliance on absolute pow er output alone.[000574] Representative examples of power density ratios for a 2-2- 1 battery pack configuration are summarized in Table 13.Table 13: Power Density' Ratios (2-2-1 Configuration)Representative Power Density Ratios — 2-Over-3 Configuration[000575] In some embodiments, a battery pack having a 2-over-3 battery cell configuration, such as battery pack 500, is characterized by power density' ratios that relate electrical power delivery' capability' to the physical size of the battery' pack. These ratios provide a size-normalized measureP-WO-TN-2025-0009 / / 1076-0022WO Patent of performance that facilitates comparison across batters’ pack configurations and operating conditions.[000576] In some embodiments, a ratio of continuous electrical power to total battery pack displacement volume characterizes sustained power delivery capability normalized by pack size. In representative embodiments, assuming a battery voltage of approximately 20 volts, this ratio has a nominal value of approximately 5.12 watts per cubic centimeter, with values ranging from approximately 2.01 watts per cubic centimeter to approximately 6.27 watts per cubic centimeter. This ratio reflects the ability of the battery' pack to support sustained high-power operation within a compact volumetric envelope.[000577] In some embodiments, a ratio of pulsed electrical power to total battery' pack displacement volume characterizes short-duration power delivery capability normalized by pack size. In representative embodiments, assuming a battery pack voltage of approximately 20 volts, this ratio has a nominal value of approximately 11.1 watts per cubic centimeter, with values ranging from approximately 6.02 watts per cubic centimeter to approximately 13 watts per cubic centimeter. Such pulsed power density may support transient high-load events, including tool startup, rapid acceleration, or brief torque spikes.[000578] The power density ratios described herein provide a normalized characterization of battery pack performance that remains applicable as battery cell technology, electronics, and motor efficiency evolve. By relating power delivery capability to physical volume, these ratios define a performance envelope that constrains future high-power compact tool designs without reliance on absolute voltage, chemistry', or motor configuration.[000579] Representative examples of power density ratios for a 2-over-3 battery pack configuration are summarized in Table 14.Table 14: Power Density Ratios — 2-Over-3 ConfigurationMetric Nominal Min Max Units DescriptionRepresentative Air Displacement-to-Battery Pack Displacement Ratios[000580] In some embodiments, a battery pack as described herein is further characterized by ratios that relate non-component air volume within the battery’ pack housing cavity volume to the overall battery pack displacement volume. Such ratios characterize the extent of unused or nonfunctional volume within the battery' pack housing and provide a measure of dead-volume efficiency.[000581] In some embodiments, an air displacement-to-battery pack displacement ratio characterizes the fraction of the battery' pack housing cavity volume occupied by internal airP-WO-TN-2025-0009 / / 1076-0022WO Patent cavities that do not contain battery cells, printed circuit boards and associated / attached components, electrical connectors, terminals, or structural carrier components. Lower values of this ratio correspond to increased volumetric efficiency and reduced unused internal volume.[000582] In representative embodiments having a 2-2-1 battery’ cell configuration, such as battery pack 1800, the ratio of air displacement volume to battery pack displacement volume has a nominal value of approximately 0.037, with values ranging from approximately 0.028 to approximately 0.070. These values reflect variation in internal cavity' volume associated with manufacturing tolerances, housing geometry', and component placement within the battery pack.[000583] In representative embodiments having a 2-over-3 battery' cell configuration, such as battery pack 500, the ratio of air displacement volume to battery pack displacement volume has a nominal value of approximately 0.016. In some embodiments, this lower ratio reflects a more densely’ packed internal architecture with reduced non-component air volume. Because representative embodiments of the 2-over-3 configuration exhibit reduced internal cavity variation, minimum and maximum values for this ratio are not required to be present in a single embodiment.[000584] The air displacement-to-battery pack displacement ratios described herein provide an additional volumetric efficiency metric that complements the cell volume-based ratios described with reference to Tables 10-14 and further characterize internal space utilization within the battery pack housing.[000585] Representative examples of air displacement-to-battery pack displacement ratios are summarized in Table 15. In some embodiments, the 2-over-3 configuration exhibits a nominal airdisplacement fraction of approximately 0.016. In representative datasets presently characterized, variation about this nominal value was not separately tabulated; accordingly, Table 15 lists a nominal value without mentioning a corresponding minimum and maximum.Table 15: Air Displacement-to-Battery Pack Displacement RatiosRepresentative Cell Volume Relative to Net Usable Battery Pack VolumeP-WO-TN-2025-0009 / / 1076-0022WO Patent [000586] In some embodiments, a battery pack as described herein is further characterized by ratios that relate the volume of energy -storing battery cells to a net usable volume of the battery pack. The net usable volume may be defined as the overall battery pack displacement volume minus internal air displacement volume, thereby excluding non-functional internal cavities from the volumetric efficiency calculation.[000587] In some embodiments, a ratio of total battery cell displacement volume to net usable battery pack volume characterizes how efficiently the usable internal volume of the battery7pack is occupied by energy -storing battery cells. By excluding internal air cavities, this ratio provides a refined measure of functional volumetric efficiency that isolates battery7cell utilization from housing thickness, external geometry', and internal void space.[000588] In representative embodiments having a 2-2-1 battery cell configuration, such as battery pack 1800, the ratio of total battery cell displacement volume to net usable battery pack volume has a nominal value of approximately 0.325, with values ranging from approximately 0.308 to approximately 0.370. These values indicate that a substantial portion of the net usable battery pack volume is occupied by energy -storing battery7cells.[000589] In representative embodiments having a 2-over-3 battery cell configuration, such as battery pack 500, the ratio of total battery cell displacement volume to net usable battery pack volume has a nominal value of approximately 0.422, with values ranging from approximately 0.372 to approximately 0.510. These values reflect increased net functional volumetric efficiency in the higher-capacity configuration, resulting from reduced internal air volume and a more densely packed internal architecture.[000590] The net usable volumetric efficiency ratios described herein complement the volumetric packaging efficiency ratios described with reference to Tables 10 and 11 and the air displacement ratios described with reference to Table 15. Together, these ratios provide a comprehensive characterization of internal space utilization that constrains achievable battery pack designs independent of battery chemistry or electrical performance alone.[000591] Representative examples of cell volume relative to net usable battery pack volume are summarized in Table 16.Table 16: Cell Volume Relative to Net Usable Battery Pack VolumeP-WO-TN-2025-0009 / / 1076-0022WO PatentRepresentative Cell Volume Relative to Handle Displacement Volume[000592] In some embodiments, a batters pack as described herein is further characterized by ratios that relate the volume of energy-storing battery cells to a handle displacement volume associated with the battery pack and the power tool handle region. The handle displacement volume may correspond to a volume of housing material and structural features associated with a handle assembly and bottom cap region of the battery pack, rather than a total internal cavity or envelope volume.[000593] In some embodiments, a ratio of total battery cell displacement volume to handle displacement volume characterizes the degree to which energy storage is integrated relative to handle-related structural material of the battery pack. The handle displacement volume may represent a volume of housing material and structural features associated with a handle assembly and bottom cap region of the battery pack, rather than a total internal cavity or bounding envelope. Accordingly, such ratios provide a system-adjacent measure of packaging efficiency that relates battery energy storage to a user-facing geometric constraint without requiring that the handle displacement volume define a strict volumetric boundary for battery cell placement.[000594] In representative embodiments having a 2-2-1 battery cell configuration, such as battery pack 1800, the ratio of total battery cell displacement volume to handle displacement volume has a nominal value of approximately 0.78, indicating that a substantial volume of energy-storing battery cells is supported relative to the handle-associated structural volume.[000595] In representative embodiments having a 2-over-3 battery cell configuration, such as battery pack 500, the ratio of total battery cell displacement volume to handle displacement volume has a nominal value of approximately 1.09, reflecting increased integration of battery cell volume relative to handle-associated structural material. In some embodiments, values greater than 1 indicate that battery cells occupy regions supported by, adjacent to. or extending beyond portions of the handle-associated structure, rather than being confined within a handle-defined volumetric envelope.[000596] The cell volume-to-handle displacement ratios described above provide an additional system-level characterization of battery pack integration that complements the handle interface cross-sectional area ratios described with reference to Table 12. Together, these ratios constrain achievable energy storage within ergonomically constrained regions of the tool independent of batten- chemistry' or electrical performance alone.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000597] Representative examples of cell volume relative to handle displacement volume are summarized in Table 17.Table 17: Cell Volume Relative to Handle- Associated Structure Volume Configuration Metric Nominal DescriptionRepresentative Internal Handle Cavity Volume and Component Fill Characteristics — 2-2-1 Configuration[000598] In some embodiments, a battery pack as described herein is further characterized by internal volumetric relationships associated with a handle-located portion of the battery pack. These relationships descnbe how effectively internal cavity volume within the handle region is occupied by functional battery pack components and provide an additional geometry-based characterization of volumetric efficiency that is independent of battery chemistry or electrical output capability.[000599] In some embodiments, the battery pack includes a battery pack housing defining an interior handle cavity volume. The interior handle cavity volume corresponds to the volume bounded by an inner surface of the battery pack housing within a defined handle region of the battery pack. The handle region may be defined as a portion of the battery pack configured to be grasped by a user when installed in the power tool and may be bounded along the insertion axis by a plane oriented transverse to the insertion axis at a transition between a user-grippable portion of the battery pack and a tool-facing interface portion of the battery pack.[000600] In some embodiments, the battery pack further includes a plurality of functional battery pack components positioned within the interior handle cavity volume. Such components may include, without limitation, a plurality of battery cells, electrical interconnection elements (e.g., battery straps or bus bars), a PCB, and electronic components mounted to the PCB.[000601] As used herein, component displacement volume refers to the combined volume occupied by the functional battery pack components positioned within the interior handle cavity volume. The component displacement volume may be determined by measurement. CAD-derived volume, or other volumetric determination techniques applied to the components located within the defined cavity region.[000602] In some embodiments, an unoccupied internal volume within the handle region may be defined as a derived quantity corresponding to the difference between the interior handle cavity volume and the component displacement volume. This unoccupied internal volume representsP-WO-TN-2025-0009 / / 1076-0022WO Patent internal cavity volume not occupied by the defined functional components and may include assembly clearances, manufacturing tolerances, and non-component void regions. The unoccupied internal volume is not required to be independently measured.[000603] In some embodiments, a component fill ratio is defined as a ratio of the component displacement volume to the interior handle cavity volume. This ratio provides a quantitative measure of how fully the interior handle cavity volume is occupied by functional battery' pack components.[000604] In representative embodiments having a 2-2-1 battery' cell configuration, such as battery' pack 1800, the interior handle cavity' volume has a nominal value of approximately 67.0 cubic centimeters. In some embodiments, the component displacement volume within the interior handle cavity' volume has a nominal value of approximately' 63.7 cubic centimeters.[000605] In representative embodiments, the resulting component fill ratio has a nominal value of approximately 0.95, indicating that a substantial majority' of the interior handle cavity7volume is occupied by functional battery pack components. In some embodiments, such high component fill ratios reflect a densely packaged internal architecture within ergonomically constrained handle regions of the power tool system.[000606] In some embodiments, the battery pack is further characterized by a relationship between battery7cell volume and the interior handle cavity volume. In such embodiments, a cell-to-cavity volume ratio may be defined as a ratio of a total battery7cell displacement volume associated with the battery pack to the interior handle cavity volume. The total battery cell displacement volume may correspond to the aggregate volume of all battery cells contained within the battery7pack, as described elsewhere herein.[000607] In representative embodiments having a 2-2-1 battery7cell configuration, the total battery' cell displacement volume is approximately 44.5 cubic centimeters, resulting in a nominal cell-to-cavity volume ratio of approximately 0.66 when referenced to the interior handle cavity volume. This ratio provides an additional measure of the extent to which energy-storing battery cells are integrated relative to available internal cavity7volume within the handle region.[000608] The internal cavity7volume, component displacement volume, unoccupied internal volume, and associated ratios described herein provide a geometry-based characterization of internal space utilization within the handle region of the battery pack. These metrics complement the volumetric packaging efficiency ratios described elsewhere in this disclosure and provide additional constraints on battery7pack architectures intended to maximize energy storage and functional component integration within ergonomically constrained tool handles.[000609] Representative examples of internal handle cavity volume characteristics and associated volumetric ratios for a 2-2-1 battery pack configuration are summarized in Table 18.Table 18: Internal Handle Cavity7Utilization and Volumetric Efficiency (2-2-1 Battery7Pack Configuration)P-WO-TN-2025-0009 / / 1076-0022WO PatentP-WO-TN-2025-0009 / / 1076-0022WO PatentExample Adapters[000610] Power tools are often designed around a particular battery pack format. The size, shape, and installation method of the battery pack may be closely integrated with the handle of the tool in order to achieve a compact profile, balanced weight distribution, and a comfortable grip. While this approach can work well for a given battery design, it can also make it difficult to use other battery packs that do not match the original form factor.[000611] As battery technology evolves, newer battery packs may be introduced with different housing shapes, different electrical interfaces, or different installation orientations. In other cases, users may already own battery packs from another tool platform or from an earlier generation of tools. Even if these battery packs are capable of providing suitable electrical power, they may not physically fit within the handle of the tool or may not connect in the intended way.[000612] To address this, some aspects of the present disclosure relate to an adapter that allows a power tool to be used with battery packs that may differ from the battery pack for which the tool was originally designed. The adapter is positioned between the handle assembly of the power tool and a battery pack and provides an intermediate mechanical and electrical interface.[000613] In use, the adapter installs into the battery receptacle of a power tool, in place of a battery pack. Once installed, the adapter provides a separate interface that receives a battery pack. The adapter may be provided in different configurations to accommodate battery' packs having different sizes, shapes, or installation directions. In some embodiments, multiple battery' packs may share a common electrical or mechanical connection interface, and the adapter may be configured to mate with that common interface while accommodating differences in battery pack housing, size, or form factor. In this way, the adapter effectively adapts the battery interface of the power tool without requiring changes to the tool housing or internal components.[000614] Using an adapter can provide several advantages. An adapter can allow legacy battery packs to be used with newer tools, or allow newer battery packs to be used with existing tools. An adapter can allow a single tool platform to support multiple battery pack formats. An adapter can allow battery packs to be positioned relative to the handle in a way that improves balance, handling, or user comfort. Unlike a battery pack, in most cases, the adapter does not itself store electrical energy and instead functions as a structural and electrical intermediary configured to adapt incompatible battery interfaces.[000615] FIG. 26 A illustrates a perspective view of an adapter 2600 in accordance with some embodiments of the present disclosure. The adapter 2600 is shown separate from a power tool and separate from a battery' pack in order to illustrate structural features of the adapter 2600 without obstruction.P-WO-TN-2025-0009 / / 1076-0022WO Patent [000616] FIG. 26B illustrates an exploded view of the power tool 10 of FIG. 1, with the adapter 2600 of FIG. 26A and a battery pack 2630 shown separated from one another and from the handle assembly 12 of the power tool 10. FIG. 26C illustrates the power tool 10 with the adapter 2600 installed in the battery receptacle cavity 115 of the handle assembly 12 and with the battery pack 2630 separated from the adapter 2600. FIG. 26D illustrates the power tool 10 with the adapter 2600 installed in the handle assembly 12 and the battery' pack 2630 coupled to the a...

Claims

P-WO-TN-2025-0009 / / 1076-0022WO Patent WHAT IS CLAIMED IS:

1. A power tool comprising:a housing including a motor housing that supports an electric motor and a handle assembly extending from the motor housing, the handle assembly providing a partial grip surface; and a battery pack configured to mount into the handle assembly, the battery pack having a geometry complementary to the handle assembly,wherein the battery pack and the handle assembly together form a grip surface for user engagement.

2. The power tool of claim 1 , wherein the battery' pack includes a first housing portion, a second housing portion oriented coaxially with the first housing portion and having a greater circumference than the first housing portion, at least one first battery7cell housed within the first housing portion, and a plurality of second battery cells housed within the second housing portion.

3. The power tool of claim 2, wherein the first housing portion is received at least partially into the handle assembly of the power tool, and wherein the second housing portion includes geometry complementary to the handle assembly to form the grip surface together with the handle assembly.

4. The power tool of claim 1, wherein the handle assembly forms a first partial handle assembly and the battery pack forms a second partial handle assembly that complements the first partial handle assembly to form a grip handle for the power tool when the battery pack is mounted into the handle assembly.

5. The power tool of claim 2, wherein the second housing portion fully captures the plurality7of second battery7cells and overlaps a portion of the at least one first battery cell.

6. The power tool of claim 2, wherein the battery pack includes a cell holder having a first cell holder portion configured to hold the at least one first battery' cell along a center axis of the first housing portion, and a second cell holder portion configured to hold the plurality7of second battery cells along a center axis of the second housing portion.

7. The power tool of claim 6, wherein the first housing portion is coaxial with the second housing portion.

8. The power tool of claim 1 , wherein, when the battery pack is mounted in the handle assembly, at least one battery cell of the battery pack is positioned at least partially within the handle assembly and at least one battery cell of the battery pack is positioned at least partially outside the handle assembly.

9. The power tool of claim 1, wherein, when the battery pack is mounted in the handle assembly, at least two battery cells of the battery pack are positioned at least partially within an interior volume defined by the handle assembly.

10. The power tool of claim 1 , wherein, when the battery pack is mounted in the handle assembly, at least four battery7cells of the battery7pack are positioned at least partially within an interior volume defined by the handle assembly.P-WO-TN-2025-0009 / / 1076-0022WO Patent 11. The power tool of claim 10. wherein, when the batery pack is mounted in the handle assembly, at least two batery cells of the batery pack are positioned entirely within the interior volume defined by the handle assembly.

12. The power tool of Claim 1. wherein the electric motor has an operating voltage of greater than approximately 14 volts, wherein the handle assembly extends from the motor housing along a handle axis, the handle assembly comprising an exterior surface defining a first grip surface region configured for user engagement and a batery receptacle cavity positioned inward of the exterior surface and opening at an end of the handle assembly opposite the motor housing, and wherein the battery pack is removably receivable within the batery receptacle cavity along an insertion axis that is substantially coincident with the handle axis, the batery pack having a nominal voltage of greater than approximately 14 volts and comprising:a first housing portion that houses at least a portion of a first set of batery cells and is configured to be at least partially received within the batery receptacle canty: anda second housing portion that houses at least a portion of a second set of battery cells, the second housing portion extending from the first housing portion along the insertion axis and being configured to remain outside the batery receptacle cavity when the batery pack is received by the handle assembly, the second housing portion having an exterior surface defining a second grip surface region,wherein, when the first housing portion of the batery pack is received within the batery’ receptacle cavity, the second grip surface region is positioned adjacent the first grip surface region along the insertion axis such that the first grip surface region and the second grip surface region collectively define a continuous grip surface extending along the handle axis, and wherein the insertion axis extends through a space between the first set of batery’ cells and a space between the second set of batery’ cells.

13. The power tool of claim 1, wherein the handle assembly extends from the motor housing along a handle axis and includes an exterior surface defining a first grip surface region and a batery receptacle cavity positioned inward of the exterior surface and opening at an end of the handle assembly opposite the motor housing, the batery' receptacle cavity being shaped to receive the batery pack along an insertion axis that is substantially coincident with the handle axis, and wherein the batery’ pack comprises:a first housing portion that houses at least a portion of at least one first batery cell and is configured to be at least partially received within the batery’ receptacle cavity’; anda second housing portion that houses at least a portion of at least one second batery cell, the second housing portion extending from the first housing portion and defining a second grip surface region positioned adjacent the first grip surface region such that the first grip surface region and the second grip surface region together form a continuous grip surface extending along the handle axis.

14. The power tool of claim 1, wherein the batery’ pack comprises:a first housing portion consisting of a first set of two batery cells configured to be received within a batery’ receptacle cavity of the handle assembly along an insertion axis; andP-WO-TN-2025-0009 / / 1076-0022WO Patent a second housing portion consisting of a second set of three battery cells extending axially along the insertion axis from the first housing portion and configured to remain at least partially outside the battery receptacle cavity when the first housing portion is received within the battery receptacle cavity, the second housing portion having an exterior surface defining a second grip surface region configured to be positioned adjacent a first grip surface region of the handle assembly,wherein, when the first housing portion is received within the battery receptacle cavity of the handle assembly, the second grip surface region is positioned adjacent the first grip surface region such that the first grip surface region and the second grip surface region collectively define a continuous grip surface extending along a handle axis of the power tool.

15. The power tool of claim 1 , wherein the battery pack includes a housing comprising: a first housing section extending along a longitudinal axis and having a first transverse dimension;a second housing section extending along the longitudinal axis and having a second transverse dimension greater than the first transverse dimension;a terminal wall disposed at an axial end of the first housing section and configured to support battery pack electrical terminals; anda radially spring-biased circumferential retention feature formed on the terminal wall or the first housing section and configured to engage a complementary retention element of the power tool,wherein the first housing section is configured to be received within a receptacle formed by the handle assembly, andwherein the second housing section is configured to remain outside the receptacle to form an external gripping surface of the battery pack.

16. The power tool of claim 1 , wherein the battery pack comprises a housing including: a first cell-receiving region shaped to receive a first set of battery cells arranged side-by-side in a radial direction, each of the first set of battery cells having a longitudinal axis generally parallel to a longitudinal axis of the housing; anda second cell-receiving region adjacent to the first cell-receiving region along the longitudinal axis of the housing and shaped to receive a second set of battery cells arranged side-by-side in a radial direction, the longitudinal axis of the housing being positioned in a space between the battery’ cells of the second set of battery cells, each of the second set of battery cells having a longitudinal axis generally parallel to the longitudinal axis of the housing; and electrical conductors configured to interconnect all battery cells received in the first and second cell-receiving regions in a single series circuit.

17. The power tool of claim 1, wherein the battery pack comprises a housing having a longitudinal axis and being configured to be at least partially received within the handle assembly, and a plurality’ of battery’ cells electrically connected in series to form a single series battery’ circuit, the plurality of battery cells including at least five battery cells,P-WO-TN-2025-0009 / / 1076-0022WO Patent wherein the plurality of battery cells are arranged in a longitudinally stacked configuration along the longitudinal axis of the housing and divided into at least a first cell group and a second cell group that are axially offset from one another, andwherein the first cell group is positioned closer to a first axial end of the housing than the second cell group.

18. The power tool of claim 1, wherein the battery pack is a removable battery pack and comprises a housing having a longitudinal axis and being configured to be removably received by a handle region of the handle assembly,a two-cell portion of the housing containing exactly two battery cells, anda three-cell portion of the housing containing exactly three battery cells,wherein a majority of the two-cell portion is configured to be received within an interior volume of the handle region when the battery pack is installed in the power tool,wherein a majority of the three-cell portion is configured to remain external to the handle region when the battery pack is installed in the power tool, andwherein the three-cell portion of the housing has an outer perimeter that substantially matches a perimeter of the handle region that receives the two-cell portion such that the handle region and the three-cell portion collectively form a continuous handle profile.

19. The power tool of claim 1. wherein the battery pack is a removable battery pack and comprises a housing having a longitudinal axis and a support frame disposed within the housing,a two-cell portion including exactly two battery' cells supported by the support frame, each of the two battery' cells having a longitudinal axis generally parallel to the longitudinal axis of the housing, anda three-cell portion including exactly three battery cells supported by the support frame, each of the three battery cells having a longitudinal axis generally parallel to the longitudinal axis of the housing,wherein the support frame includes a first partitioning wall positioned between and separating the two battery cells of the two-cell portion, andwherein the support frame includes a second partitioning wall positioned between a first cylindrical battery cell of the three-cell portion and two other battery cells of the three-cell portion.

20. The power tool of claim 1. wherein the battery pack is a removable battery pack and comprises a housing having a longitudinal axis,a first two-cell portion of the housing including exactly two battery cells, each of the two battery cells having a longitudinal axis generally parallel to the longitudinal axis of the housing, a second two-cell portion of the housing including exactly two battery cells, each of the two battery cells having a longitudinal axis generally parallel to the longitudinal axis of the housing, anda single-cell portion of the housing including exactly one cylindrical battery cell positioned at a different axial orientation than the battery cells of the first two-cell portion and the second two-cell portion.P-WO-TN-2025-0009 / / 1076-0022WO Patent 21. The power tool of claim 1, wherein the batery pack compnses a housing having a longitudinal axis and five batery cells arranged within the housing as a two-cell group and a threecell group,wherein the five battery cells are electrically connected in a single series electrical circuit by one or more conductive interconnection members, andwherein each conductive interconnection member spans an axial distance along the longitudinal axis of the housing that is less than an axial length of any one of the batery7cells.

22. The power tool of claim 1, wherein the batery7pack comprises a housing and five batery cells arranged within the housing as a first two-cell group, a second two-cell group, and a single-cell group,wherein the five batery cells are electrically connected in a single series electrical circuit by one or more conductive interconnection members, andwherein each conductive interconnection member is configured such that it does not extend across an entire axial length of any batery cell from a first axial end of the batery cell to an opposite axial end of the battery cell.

23. The power tool of claim 1, wherein the batery pack comprises an elongate housing having a longitudinal axis, a distal end, and a proximal end, a plurality7of batery cells disposed within the housing, and a set of batery pack electrical terminals including at least a positive power terminal and a negative power terminal positioned at the distal end of the housing,wherein the batery pack is configured to be received, distal end first, by a batery7receptacle formed by the handle assembly in an upward direction along an insertion axis substantially parallel to the longitudinal axis,wherein the power tool includes a grip registration plane corresponding to a nominal position of a user’s hand when gripping the handle assembly, the grip registration plane extending generally horizontally and substantially bisecting a trigger assembly of the power tool, and wherein, when the batery pack is matingly received in the power tool, at least a portion of the distal end of the housing and the batery pack electrical terminals are positioned upward of the grip registration plane.

24. The power tool of claim 1, further comprising a control assembly disposed within the handle assembly and electrically coupled to the electric motor, and a terminal block supported by the control assembly and comprising a plurality of tool-side batery terminals extending into a batery receptacle cavity formed by the handle assembly,wherein the tool-side batery terminals are configured to electrically mate with the batery¬ pack when the batery7pack is received within the batery receptacle cavity, andwherein, when the batery pack is seated within the batery7receptacle cavity, at least a portion of the tool-side batery terminals extends into an interior region of the batery pack.

25. The power tool of claim 1, wherein the batery7pack is configured for removable insertion into the power tool and comprises a housing, one or more batery7cells disposed within the housing, and a plurality7of batery7terminals exposed at a first end of the housing and configured to electrically connect with the power tool,P-WO-TN-2025-0009 / / 1076-0022WO Patent a printed circuit board disposed within the housing at a location adjacent to a housing parting line and at an end of the housing opposite the battery terminals,state-of-charge circuitry and a user-actuatable push button mounted on the printed circuit board,at least one light opening formed at the housing parting line, andat least one state-of-charge indicator light-emitting diode mounted on the printed circuit board, positioned at the housing parting line and aligned with the at least one light opening, wherein the housing positions the printed circuit board such that the at least one state-of-charge indicator light-emitting diode is supported at the housing parting line and emits light externally from the battery pack through the at least one light opening.

26. The power tool of claim 1, wherein the handle assembly extends from the motor housing along a handle axis and includes an exterior surface defining a grip surface region configured for user engagement and a battery receptacle cavity positioned inward of the exterior surface and opening at an end of the handle assembly opposite the motor housing, and wherein the battery pack is removably receivable within the battery receptacle cavity along an insertion axis that is generally aligned with the handle axis, the battery pack comprising a plurality of battery cells,wherein the battery pack defines a total battery pack displacement volume,wherein the plurality of battery cells define a total battery cell displacement volume, and wherein a ratio of the total battery cell displacement volume to the total battery' pack displacement volume is in a range of approximately 0.285 to approximately 0. 15.

27. A power tool comprising:a motor housing configured to house an electric motor having an operating voltage of greater than approximately 14 volts;a handle housing extending from the motor housing along a handle axis, the handle housing comprising an exterior surface defining a first grip surface region configured for user engagement, and a battery receptacle cavity positioned inward of the exterior surface and opening at an end of the handle housing opposite the motor housing; anda battery pack removably receivable within the battery receptacle cavity along an insertion axis that is substantially coincident with the handle axis, the battery pack having a nominal voltage of greater than approximately 14 volts and comprising:a first housing portion that houses at least a portion of a first set of battery cells and is configured to be at least partially received within the battery’ receptacle canty: anda second housing portion that houses at least a portion of a second set of battery' cells, the second housing portion extending from the first housing portion along the insertion axis and being configured to remain outside the battery’ receptacle cavity’ when the battery' pack is received by the handle housing, the second housing portion having an exterior surface defining a second grip surface region,wherein, when the first housing portion of the battery’ pack is received within the battery receptacle cavity, the second grip surface region is positioned adjacent the first grip surface regionP-WO-TN-2025-0009 / / 1076-0022WO Patent along the insertion axis such that the first grip surface region and the second grip surface region collectively define a continuous grip surface extending along the handle axis, andwherein the insertion axis extends through a space between the first set of battery cells and a space between the second set of batten- cells.

28. The power tool of claim 27, wherein the second grip surface region is contoured such that the continuous grip surface extends without a protruding interface between the handle housing and the second housing portion.

29. The power tool of claim 27, wherein the second housing portion has a greater outer dimension than the first housing portion.

30. The power tool of claim 27, wherein the first housing portion and the second housing portion are coaxially arranged along the insertion axis.

31. The power tool of claim 27, wherein the battery pack includes a stepped surface between the first housing portion and the second housing portion, the stepped surface being shaped to engage an end surface of the handle housing when the battery pack is received within the battery receptacle cavity.

32. The power tool of claim 31, wherein the stepped surface is located around at least one battery cell of the first set of battery cells.

33. The power tool of claim 27, wherein the first set of battery cells is arranged side-by-side in a radial direction, each battery cell of the first set having a longitudinal axis generally parallel to the insertion axis, and wherein the first set of battery cells is located entirely within the handle housing when the battery pack is received in the battery receptacle cavity.

34. The power tool of claim 33, wherein the second set of battery cells is arranged side-by-side in a radial direction, and wherein the first set of battery cells and the second set of battery cells are arranged in an axially stacked configuration along the insertion axis such that the second set of battery cells is positioned axially adjacent the first set of battery cells.

35. The power tool of claim 33, wherein the second set of battery cells is arranged around the insertion axis, and wherein each battery cell of the second set has a longitudinal axis that is at an angle of less than approximately 10 degrees relative to the insertion axis.

36. The power tool of claim 35, wherein the first set of battery cells includes exactly two battery cells, and wherein the second set of battery cells includes exactly three battery cells.

37. The power tool of claim 34, further comprising a third battery cell positioned adjacent the second set of battery cells, the third battery cell having a longitudinal axis oriented non-parallel to the insertion axis.

38. The power tool of claim 37, wherein the first set of battery cells includes exactly two battery cells, wherein the second set of battery cells includes exactly two battery cells, and wherein the third battery cell is a single battery- cell.

39. The power tool of claim 37, wherein the first set of battery cells, the second set of battery cells, and the third battery cell are arranged in a stacked configuration, and wherein the second set of battery cells is positioned between the first set of battery cells and the third battery cell.P-WO-TN-2025-0009 / / 1076-0022WO Patent 40. The power tool of claim 37, wherein a portion of the second housing portion that houses the third batters’ cell has a perimeter that is no more than 25% greater than a perimeter of the first housing portion.

41. The power tool of claim 37, wherein the first set of batters’ cells, the second set of battery cells, and the third battery' cell are electrically connected in series.

42. The power tool of claim 27, wherein the handle axis is generally transverse to a longitudinal axis of the motor housing.

43. The power tool of claim 27, wherein the handle axis is generally parallel to a longitudinal axis of the motor housing.

44. The power tool of claim 27, further comprising a terminal block positioned adj acent an upper end of the battery receptacle cavity7and configured to electrically couple to terminals of the battery pack when the battery' pack is received within the battery' receptacle cavity.

45. The power tool of claim 27, further comprising a retention mechanism configured to releasably retain the battery pack within the battery receptacle cavity.

46. The power tool of claim 27, wherein at least one battery cell of the first set extends along a first axis and at least one battery cell of the second set extends along a second axis that is at an angle in the range of 0 to 10 degrees relative to the first axis.

47. The power tool of claim 27. wherein at least one battery cell of the second set extends at an angle in the range of 0 to 10 degrees relative to the insertion axis.

48. The pow er tool of claim 27, wherein the first housing portion extends along a first axis and the second housing portion extends along a second axis that is at an angle in the range of 0 to 10 degrees relative to the first axis.

49. The pow er tool of claim 27, wherein the second housing portion extends at an angle in the range of 0 to 10 degrees relative to the insertion axis.

50. The power tool of claim 27, further comprising a trigger switch disposed on the handle housing, wherein, in a grip position of a user’s hand with the user’s index finger engaging the trigger switch, a pinky' finger of the user’s hand engages the second housing portion of the battery pack.

51. The power tool of claim 27, wherein a perimeter of the second housing portion is no more than 25% greater than a perimeter of the first housing portion.

52. The power tool of claim 27, wherein at least one battery cell of the first set is electrically connected in series with at least one battery cell of the second set.

53. A power tool system comprising:a power tool including:a motor housing configured to house an electric motor; anda handle housing extending from the motor housing along a handle axis, the handle housing having an exterior surface defining a first grip surface region and a battery7receptacle cavity7positioned inward of the exterior surface and opening at an end of the handle housing opposite the motor housing, the battery receptacle cavity being shaped to receive a battery' pack along an insertion axis that is substantially coincident with the handle axis; andP-WO-TN-2025-0009 / / 1076-0022WO Patent a batery pack receivable in the batery receptacle cavity, wherein the batery pack comprises a first housing portion that houses at least a portion of at least one first batery cell at least partially received within the batery receptacle cavity, and a second housing portion that houses at least a portion of at least one second batery cell extending from the first housing portion and defines a second grip surface region positioned adjacent the first grip surface region such that the first grip surface region and the second grip surface region together form a continuous grip surface extending along the handle axis.

54. The power tool system of claim 53, wherein a perimeter of the second housing portion is no more than 25% greater than a perimeter of the first housing portion.

55. The power tool system of claim 53, further comprising a trigger switch disposed on the handle housing, wherein, in a grip position of a user’s hand with the user’s index finger engaging the trigger switch, a pinky finger of the user’s hand engages the second housing portion of the batery pack.

56. A batery pack for a power tool comprising:a first housing portion consisting of a first set of two batery cells configured to be received within a batery receptacle cavity of a handle housing of the power tool along an insertion axis;a second housing portion consisting of a second set of three batery cells extending axially along the insertion axis from the first housing portion and configured to remain at least partially outside the battery receptacle cavity when the first housing portion is received within the battery’ receptacle cavity, the second housing portion having an exterior surface defining a second grip surface region configured to be positioned adjacent a first grip surface region of the handle housing;wherein, when the first housing portion is received within the battery’ receptacle cavity’ of the handle housing, the second grip surface region is positioned adjacent the first grip surface region such that the first grip surface region and the second grip surface region collectively define a continuous grip surface extending along a handle axis of the power tool.

57. A batery pack housing for a power tool, comprising:a first housing section extending along a longitudinal axis and having a first transverse dimension;a second housing section extending along the longitudinal axis and having a second transverse dimension greater than the first transverse dimension;a terminal wall disposed at an axial end of the first housing section and configured to support batery pack electrical terminals; anda radially spring-biased circumferential retention feature formed on the terminal wall or the first housing section and configured to engage a complementary' retention element of the power tool,wherein the first housing section is configured to be received within a receptacle of the power tool, andwherein the second housing section is configured to remain outside the receptacle to form an external gripping surface of the batery pack.P-WO-TN-2025-0009 / / 1076-0022WO Patent 58. The baten’ pack housing of claim 57, wherein the radially spring-biased circumferential retention feature comprises a hog ring.

59. The batery pack housing of claim 58, wherein the hog ring is seated within a circumferential groove formed in the first housing section and is configured to resist axial withdrawal of the batery pack housing from the receptacle of the power tool.

60. The batery pack housing of claim 58, wherein the hog ring is positioned axially adjacent at least one of a terminal block, a printed circuit board, or an energy' storage component housed within the battery' pack.

61. The batery' pack housing of claim 58, further comprising a sensing arrangement configured to detect presence of the batery pack within the power tool by detecting a position of the hog ring, the sensing arrangement comprising at least one of a conductive sensor, a Hall-effect sensor, an inductive sensor, or a positional switch.

62. The battery pack housing of claim 57, wherein the hog ring retention mechanism is inaccessible from an exterior of the power tool when the first housing section is at least partially received within the receptacle of the power tool.

63. A method of retaining a batery pack within a power tool, comprising: inserting the batery pack into a receptacle of the power tool such that a first housing portion of the batery pack is received within the receptacle and a second housing portion of the batery pack remains outside the receptacle;forming a composite grip handle by positioning an exterior surface of the second housing portion adjacent an exterior surface of a handle housing of the power tool; andretaining the batery' pack within the receptacle using a hog ring retention mechanism, wherein the hog ring retention mechanism is inaccessible from an exterior of the pow er tool when the first housing portion of the batery’ pack is at least partially received within the receptacle of the power tool.

64. A batery pack for a power tool, comprising:a housing including:a first cell-receiving region shaped to receive a first set of batery' cells arranged side-by-side in a radial direction, each of the first set of batery cells having a longitudinal axis generally parallel to a longitudinal axis of the housing; anda second cell-receiving region adjacent to the first cell-receiving region along the longitudinal axis of the housing and shaped to receive a second set of batery cells arranged side-by-side in a radial direction, the longitudinal axis of the housing positioned in a space between the batery cells of the second set of battery cells, each of the second set of batery cells having a longitudinal axis generally parallel to the longitudinal axis of the housing; andelectrical conductors configured to interconnect all batery cells received in the first and second cell-receiving regions in a single series circuit.

65. The battery pack of claim 64. wherein the first set of battery cells includes exactly tw o batery cells, and wherein the second set of batery' cells includes exactly three batery cells.P-WO-TN-2025-0009 / / 1076-0022WO Patent 66. The baten' pack of claim 64, wherein only a single electrical conductor interconnecting the batery cells passes from one side of the longitudinal axis of the housing to an opposite side of the longitudinal axis of the housing.

67. The battery pack of claim 64. wherein the first set of batery cells comprises: a first batery cell having a negative terminal disposed at an axially outer first end of the housing and a positive terminal facing axially inward; anda second battery cell having a positive terminal disposed at the axially outer first end of the housing and a negative terminal facing axially inward;and wherein the second set of batery' cells comprises:a third batery' cell having a negative terminal facing axially inward and a positive terminal disposed at an axially outer second end of the housing;a fourth batery cell having a negative terminal disposed at the axial ly outer second end of the housing and a positive terminal facing axially inward; anda fifth batery cell having a negative terminal disposed at the axially outer second end of the housing and a positive terminal facing axially inward.

68. The batery pack of claim 64, wherein the electrical conductors are configured to interconnect the batery’ cells in the series circuit such that:the negative terminal of the first batery cell forms a first end of the series circuit; the positive terminal of the first batery cell is electrically connected to the negative terminal of the third batery' cell;the positive terminal of the third batery cell is electrically connected to the negative terminal of the fourth batery cell;the positive terminal of the fourth batery' cell is electrically connected to the negative terminal of the fifth batery' cell;the positive terminal of the fifth batery cell is electrically connected to the negative terminal of the second batery cell; andthe positive terminal of the second batery cell forms a second end of the series circuit.

69. The batery pack of claim 68, wherein the electrical connection between the positive terminal of the fourth batery cell and the negative terminal of the fifth batery cell is provided by an elongated electrical conductor that crosses the longitudinal axis of the housing.

70. The batery pack of claim 68, wherein the electrical connection between the positive terminal of the fourth batery cell and the negative terminal of the fifth batery cell is provided by an elongated electrical conductor that passes from one side of the longitudinal axis of the housing to an opposite side of the longitudinal axis of the housing, and wherein no other electrical conductor interconnecting the batery cells passes from one side of the longitudinal axis of the housing to an opposite side of the longitudinal axis of the housing.

71. The batery pack of claim 64, wherein the first cell-receiving region and the second cell-receiving region are longitudinally adjacent along the longitudinal axis of the housing.

72. The batery’ pack of claim 64, wherein the second cell -receiving region has a different transverse dimension than the first cell-receiving region.P-WO-TN-2025-0009 / / 1076-0022WO Patent 73. The batery pack of claim 64, wherein at least one of the batery cells of the second set of batery cells is axially offset relative to another of the batery cells of the second set of batery cells.

74. The batery pack of claim 64, wherein the second set of batery cells are arranged in a triangular patern around the longitudinal axis of the housing.

75. The battery pack of claim 64, wherein the electrical conductors comprise stamped or bent metal connectors configured to couple batery cells in the second cell-receiving region to batery cells in the first cell-receiving region with only a single axial crossover.

76. The battery pack of claim 64, further comprising a batery pack terminal structure at an end of the first cell-receiving region, the terminal structure including at least one electrical terminal positioned in an interstitial space between projected envelopes of the batery cells receivable in the first cell-receiving region.

77. The batery pack of claim 76, wherein the terminal structure comprises terminals for a battery pack positive power terminal, a batery pack negative power terminal, and at least one batery pack signal terminal, each located in interstitial spaces between batery cells.

78. The batery pack of claim 76. w herein the terminal structure is directly mounted to a circuit board within the housing without intervening wiring.

79. The batery pack of claim 64. wherein the housing includes internal partition walls defining boundaries between the batery cells in the first and second cell-receiving regions.

80. The batery pack of claim 64, wherein the second cell-receiving region includes a support boss positioned along the longitudinal axis of the housing.

81. The batery pack of claim 64, wherein the housing is configured such that the batery cells of the first cell-receiving region are fully enclosed, while at least one of the batery' cells of the second cell-receiving region is partially exposed.

82. The batery pack of claim 64, wherein the housing is configured to be w elded or bonded to enclose the batery cells without fasteners.

83. The batery pack of claim 64, further comprising a circuit board supporting state-of-charge indicator light-emiting diodes positioned adjacent a parting line of the housing.

84. The batery pack of claim 83, wherein the state-of-charge indicator light-emiting diodes are configured to illuminate through light pipes extending to opposite sides of the housing.

85. The batery pack of claim 64, further comprising a retention feature configured to engage a detent or spring element of a power tool to removably retain the battery pack in the power tool.

86. The batery pack of claim 85, wherein the retention feature comprises a spring-biased retention element engagement groove formed in an outer surface of the first cell-receiving region.

87. The batery pack of claim 64, w herein the housing further comprises an outer shell portion configured to enclose the first and second cell-receiving regions and define an external section sized to be received within a complementary receptacle of a power tool.P-WO-TN-2025-0009 / / 1076-0022WO Patent 88. The batery pack of claim 87, wherein the outer shell portion includes an annular engagement surface configured to cooperate with a spring-biased retention element.

89. The battery pack of claim 87, wherein the outer shell portion includes an ergonomic grip region surrounding at least part of the second cell-receiving region.

90. The batery pack of claim 87, wherein the outer shell portion includes a terminal end wall carrying batery' pack terminals positioned to directly engage tool-side terminals when the external section is received in the power tool or charger.

91. The batery pack of claim 87, wherein the outer shell portion defines internal guide features configured to receive and locate the first and second cell-receiving regions within the housing.

92. The batery pack of claim 87, wherein the outer shell portion includes internal support ribs configured to support the batery pack circuit board adjacent the terminal end wall.

93. The batery pack of claim 87, wherein the terminal end wall is aligned with the external section such that the batery pack terminals are positioned adjacent a switch assembly or terminal block of a power tool when installed.

94. The batery pack of claim 87. wherein an outer dimension of the housing corresponding to the first cell-receiving region is smaller than an outer dimension of the housing corresponding to the second cell-receiving region.

95. The batery pack of claim 87, wherein the outer shell portion defines a first external section surrounding the first cell -receiving region and a second external section surrounding the second cell-receiving region, the second external section having a greater transverse dimension than the first external section.

96. The batery' pack of claim 87, wherein the first external section is sized to be received within a handle receptacle of a power tool, and the second external section forms an external grip region that remains outside the handle receptacle when the battery' pack is installed.

97. The batery pack of claim 87, wherein a transition between the first external section and the second external section is defined by a step or shoulder configured to limit insertion depth into the power tool and constrain orientation of the batery' pack upon insertion.

98. The battery pack of claim 64, wherein the housing defines openings at a parting line and the battery pack comprises state-of-charge indicator light-emiting diodes positioned on a circuit board adjacent the parting line such that the indicators are visible on opposite sides of the housing.

99. The battery pack of claim 64, wherein the housing defines openings at a parting line and the batery' pack comprises a buton positioned on a circuit board perpendicular to the parting line such that the buton protrudes from the housing for operation.

100. The batery' pack of claim 64, wherein each of the electrical conductors interconnecting the batery' cells has an axial length that is less than an axial length of any of the battery cells received in the first or second cell-receiving regions.

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