Battery pack

Abstract

The invention discloses a battery pack. The battery pack includes: a case; the battery cell is accommodated in the shell, and the battery cell comprises an electrode; the bracket is accommodated in the shell and is used for supporting the battery cell; the first metal plate is contained in the shell, the first metal plate is roughly perpendicular to the central axis of the battery cell, the first metal plate is provided with an opening, and when the battery cell is subjected to thermal runaway, airflow jetted at the electrode penetrates through the opening of the first metal plate; the second metal plate is contained in the shell, the second metal plate is roughly parallel to the first metal plate, the second metal plate and the first metal plate form an exhaust channel, and the exhaust channel guides airflow to be exhausted out of the shell.

Description

Technical Field

[0001] This application relates to the field of power tool technology, and more specifically to a battery pack. Background Technology

[0002] After evolving from manual to fuel-powered systems, most tools widely used in landscaping, construction, and other applications now utilize lithium batteries for power. A key aspect of lithium battery technology is safety, which encompasses both microscopic safety (related to the materials used in the cell's positive and negative electrodes) and macroscopic safety (involving waterproofing, insulation, heat dissipation, fire resistance, resistance to compression and drops). Improving the overall performance of the battery pack and enhancing its adaptability to harsh working conditions requires a comprehensive consideration of these factors.

[0003] This section provides background information related to this application, which is not necessarily prior art. Summary of the Invention

[0004] One objective of this application is to solve or at least alleviate some or all of the aforementioned problems. To this end, this application provides a battery pack. The technical solution adopted in this application is as follows:

[0005] A battery pack includes: a housing; a plurality of battery cells housed within the housing, each battery cell including electrodes; a support frame housed within the housing and supporting the battery cells, the support frame having end faces corresponding to the electrode positions of the battery cells, and the end faces having openings exposing the electrodes; and an end cap housed within the housing and mounted to the end face of the support frame; wherein a sealant is filled between the end cap and the end face, the end cap and / or the end face forming a spacer, the sealant separating several areas defined by the spacer, and the sealant partially covering the electrodes in several areas.

[0006] In some embodiments, multiple electrodes within the same area are electrically connected by a connecting piece.

[0007] In some embodiments, the connecting tab electrically connects multiple electrodes in the same area via an opening in the end face that exposes the electrodes.

[0008] In some embodiments, a groove is formed near the junction of the connecting piece and the electrode.

[0009] In some embodiments, the spacer is disposed around the connecting piece.

[0010] In some embodiments, the bracket and the end cap are coupled by a tongue-and-groove joint.

[0011] In some embodiments, the recessed and / or convex stops are provided with a sealing material, which includes a soft rubber.

[0012] In some embodiments, the cell also includes a cell body, at least a portion of which is not covered by sealant.

[0013] In some embodiments, the sealant includes one or more of one-component silicone, two-component potting compound, and expanding adhesive.

[0014] In some embodiments, the thermal conductivity of the sealant is greater than or equal to 0.3 W / (m·K).

[0015] In some embodiments, the end cap includes a flame-retardant material.

[0016] A battery pack includes: a housing; a battery cell housed within the housing, the battery cell including electrodes; a support frame housed within the housing and supporting the battery cell, the support frame having an end face corresponding to the electrode positions of the battery cell, and the end face having an opening for exposing the electrodes; and an end cap housed within the housing and mounted to the end face of the support frame; wherein a sealant is filled between the end cap and the end face, the sealant covering a plurality of electrodes, the plurality of electrodes covered by the sealant including a first type of electrode and a second type of electrode, the shortest distance between the first type of electrode and the end cap being less than the shortest distance between the second type of electrode and the end cap.

[0017] In some embodiments, the first type of electrode includes the positive electrode of the battery cell.

[0018] In some embodiments, the second type of electrode includes the negative electrode of the battery cell.

[0019] In some embodiments, a recess is formed at the location of the end cap corresponding to the electrode of the battery cell, and the recess depth of the end cap corresponding to the first type of electrode is greater than the recess depth of the end cap corresponding to the second type of electrode.

[0020] In some embodiments, a recessed protrusion is formed on the end cap at the position corresponding to the first type of electrode, facing the first type of electrode.

[0021] In some embodiments, the central local region of the recessed boss has a thin-walled feature.

[0022] In some embodiments, the thickness of the end cap corresponding to the position of the first type of electrode is less than the thickness of the end cap corresponding to the position of the second type of electrode.

[0023] In some embodiments, the end cap is fixedly mounted to the end face of the bracket by fasteners.

[0024] A method for assembling a battery cell module includes: mounting a plurality of battery cells to a bracket, each battery cell including electrodes, the bracket having an end face corresponding to the position of the electrodes of the battery cells, and the end face having an opening for exposing the electrodes; welding a connecting piece to the plurality of electrodes through the opening for exposing the electrodes on the end face; covering the surfaces of the connecting piece and the plurality of electrodes with sealant; and mounting an end cap to the end face of the bracket, wherein the end cap is pressed with sealant.

[0025] In some embodiments, the end cap and / or end face are formed with a spacer, and the sealant is used to separate several areas defined by the spacer.

[0026] In some embodiments, the plurality of electrodes covered by sealant include a first type of electrode and a second type of electrode, wherein the shortest distance between the first type of electrode and the end cap is less than the shortest distance between the second type of electrode and the end cap.

[0027] A battery pack includes: a housing; a battery cell housed within the housing, the battery cell including electrodes; a support frame housed within the housing and supporting the battery cell; a first metal plate housed within the housing, the first metal plate being substantially perpendicular to the central axis of the battery cell and having an opening, through which airflow ejected from the electrodes in the event of thermal runaway of the battery cell passes during thermal runaway; and a second metal plate housed within the housing, the second metal plate being substantially parallel to the first metal plate, the second metal plate and the first metal plate forming an exhaust channel, the exhaust channel guiding airflow out of the housing.

[0028] In some embodiments, the first metal plate has a plurality of openings that correspond one-to-one with the electrode positions of the battery cell.

[0029] In some embodiments, the housing has an airflow outlet, and at least a portion of the airflow outlet is provided with a fireproof element, which is made of a different material than the housing.

[0030] In some embodiments, the fireproof component is a metal plate having an opening located corresponding to an airflow outlet.

[0031] In some embodiments, the first metal plate and / or the second metal plate are made of aluminum alloy.

[0032] In some embodiments, the battery pack further includes a third metal plate and a fourth metal plate. The third metal plate is substantially perpendicular to the central axis of the cell and has an opening through which the airflow ejected from the electrodes passes when thermal runaway occurs in the cell. The fourth metal plate is substantially parallel to the third metal plate, and the third and fourth metal plates form an exhaust channel that guides the airflow out of the casing. The exhaust channel formed by the third and fourth metal plates is located on a different side of the cell than the exhaust channel formed by the first and second metal plates.

[0033] In some embodiments, the support has an end face corresponding to the electrode position of the cell, and the end face has an opening for exposing the electrode; the battery pack also includes an end cap, which is housed within the housing and mounted to the end face of the support; a sealant is filled between the end cap and the end face.

[0034] In some embodiments, a first metal plate is mounted to the end cap, the first metal plate being substantially parallel to the end cap.

[0035] In some embodiments, the opening of the first metal plate corresponds to the opening position of the end face of the bracket.

[0036] In some embodiments, an isolation element is formed on the end cap and / or end face, and a sealant is used to separate several areas defined by the isolation element, with the sealant covering the electrodes in several areas.

[0037] In some embodiments, multiple electrodes in the same area are electrically connected by a connecting piece, which connects the multiple electrodes in the same area through an opening on the end face that exposes the electrodes.

[0038] A battery pack includes: a housing; a cell module housed within the housing; the cell module includes: a plurality of cells, each cell including an electrode; a connecting piece electrically connecting the electrodes of the plurality of cells; wherein the connecting piece includes at least a first layer element and a second layer element, the first layer element being in direct contact with the electrode and at least partially overlapping the second layer element, the thickness of the first layer element being less than or equal to 0.5 mm, and the thickness of the second layer element being greater than or equal to the thickness of the first layer element.

[0039] A battery pack includes: a housing; a cell module housed within the housing; the cell module includes: a plurality of cells, each cell including an electrode; a connecting piece electrically connecting the electrodes of the plurality of cells; wherein the connecting piece includes at least a first layer element and a second layer element, the first layer element being in direct contact with the electrode and at least partially overlapping with the second layer element, the thickness of the first layer element being less than or equal to 2 mm, and the thickness of the second layer element being greater than or equal to the thickness of the first layer element.

[0040] In some embodiments, the first layer element has a first surface and a second surface, the thickness of the first layer element being the distance between the first surface and the second surface; the first surface is in direct contact with the electrode, and the second surface is at least partially covered by the second layer element.

[0041] In some embodiments, the thickness of the second layer element is greater than or equal to 0.5 mm.

[0042] In some embodiments, the thickness of the second layer element is greater than or equal to 0.8 mm.

[0043] In some embodiments, the thickness of the second layer element is greater than or equal to 1.2 mm.

[0044] In some embodiments, the thickness of the second layer element is greater than or equal to 2 mm.

[0045] In some embodiments, the first layer element and the second layer element are made of the same material.

[0046] In some embodiments, both the first layer element and the second layer element are made of copper-nickel composite material.

[0047] In some embodiments, the first layer element and the second layer element are made of different materials, and the thermal conductivity and / or electrical conductivity of the second layer element is greater than that of the first layer element.

[0048] In some embodiments, the second layer element is made of copper.

[0049] In some embodiments, the connecting piece is folded to form a first layer element and a second layer element.

[0050] In some embodiments, the proportion of length occupied solely by the first layer element along the current direction in the connecting piece is less than or equal to the proportion of length jointly occupied by the first layer element and the second layer element.

[0051] In some embodiments, the connecting piece has an opening through which sealant seals the electrode.

[0052] In some embodiments, the overlapping portion of the first layer element and the second layer element is disposed at the portion of the connection portion that is in contact with the positive terminal and / or negative terminal of the battery pack.

[0053] In some embodiments, the battery pack includes a support frame for supporting the battery cells, and a connecting piece is at least partially fixed to the sidewall of the battery cell module formed by the support frame.

[0054] In some embodiments, the battery pack further includes a flexible circuit board, which includes a conductive layer with through-holes for pads at its ends, and a connecting piece having a mounting portion that can be embedded in the through-holes for pads.

[0055] In some embodiments, the flexible circuit board further includes positioning holes, through which the flexible circuit board is fixedly installed to the bracket by interference fit between the positioning holes and the positioning posts on the bracket.

[0056] In some embodiments, the flexible circuit board further includes a substrate, and the shortest distance between the edge of the conductive layer and the edge of the substrate or the edge of the positioning hole is greater than or equal to 2 mm.

[0057] In some embodiments, the flexible circuit board includes a main circuit section and branch circuit sections. The branch circuit sections collect the voltage of one or more cells in the same cell module, and the multiple branch circuit sections converge into the main circuit section.

[0058] In some embodiments, the battery pack further includes a fuse and a heat insulation device, the heat insulation device including a heat insulation element disposed between the fuse and the battery cell adjacent to the fuse.

[0059] In some embodiments, the heat insulation device further includes a heat insulation element sleeved on the main circuit conductor connecting the connecting piece and the positive and / or negative terminals of the battery pack.

[0060] The advantage of this application is that it uses a second layer of elements with enhanced thickness and / or thermal / electrical conductivity to cover or partially cover the first layer of elements of the connecting piece, thereby improving the high current transmission and heat dissipation performance of the cell connecting piece in the battery pack. Attached Figure Description

[0061] Figure 1 This is a schematic diagram illustrating a scenario in which the battery pack powers a power tool in this application;

[0062] Figure 2 This is a perspective view of the battery pack as an embodiment in this application from one viewpoint;

[0063] Figure 3 yes Figure 2 A stereoscopic view of the battery pack shown from another perspective;

[0064] Figure 4 yes Figure 2 A three-dimensional view of the battery cell modules housed inside the battery pack casing shown.

[0065] Figure 5 yes Figure 2 The image shows an exploded view of part of the internal structure of the battery pack after the casing has been removed.

[0066] Figure 6 This is a perspective view of the battery pack inner support, separator, cell electrode, and connecting piece as one embodiment of this application;

[0067] Figure 7 This is a plan view of the inner end cap and the first metal plate of the battery pack as one embodiment in this application;

[0068] Figure 8 yes Figure 2 A cross-sectional view of the battery pack shown;

[0069] Figure 9 yes Figure 8 A schematic diagram showing the shortest distance between the first type of electrode, the second type of electrode and the end cap in the cross-sectional view of the battery pack, and the thickness of the end cap at the corresponding positions of the first type of electrode and the second type of electrode;

[0070] Figure 10 This is a perspective view of the internal connecting piece of the battery pack as one embodiment in this application;

[0071] Figure 11 yes Figure 10 A schematic diagram showing the thickness of the first and second layer components in the connecting piece;

[0072] Figure 12 yes Figure 10 A plan view of the electrode connection portion and opening in the connecting piece shown;

[0073] Figure 13 This is a schematic diagram showing the length occupied by the first layer of components and the length occupied by the second layer of components in the connecting piece along the current direction;

[0074] Figure 14 This is a perspective view of the internal connecting piece of the battery pack, which is another embodiment of this application;

[0075] Figure 15 yes Figure 14 The diagram shows a three-dimensional representation of the first and second layer components formed by folding the connecting piece.

[0076] Figure 16 This is a perspective view of the internal connecting piece of the battery pack, which is yet another embodiment of this application;

[0077] Figure 17 yes Figure 2 Another cross-sectional view of the battery pack shown;

[0078] Figure 18 yes Figure 17 A schematic diagram of the first metal plate, the second metal plate, and the exhaust channel between them in the cross-sectional view of the battery pack shown;

[0079] Figure 19 yes Figure 17 A schematic diagram of the third, fourth, and fifth metal plates and the exhaust passage between them in the cross-sectional view of the battery pack shown;

[0080] Figure 20 This is a schematic diagram of the fuse, heat insulation device, and battery cell in the battery pack as one embodiment of this application;

[0081] Figure 21 yes Figure 20 A partial view of the battery pack's internal heat insulation device installed on the interface board assembly and bracket;

[0082] Figure 22 This is a plan view of the battery pack cell module, flexible circuit board, and bracket as an embodiment of this application;

[0083] Figure 23 yes Figure 22 The diagram shows a plan view of the main circuit, branch circuit, conductive layer, substrate, and positioning holes of the flexible circuit board inside the battery pack.

[0084] Figure 24 yes Figure 22 Partial view of the battery pack's internal support positioning post, flexible circuit board conductive layer pad through hole, and connecting piece mounting part.

[0085] Figure 25 yes Figure 22 A 3D view of the battery pack containing the cell module, flexible circuit board, bracket, and connecting piece;

[0086] Figure 26 This is a table showing the electrical and thermal conductivity of some types of materials;

[0087] Figure 27 This is a table showing the electrical and thermal conductivity of copper-nickel composite materials at the same thickness but different proportions;

[0088] Figure 28 This is a flowchart of an assembly method for a battery cell module as an embodiment of this application.

[0089] Attached image caption:

[0090] 100. Battery pack; 100a. Battery cell module; 200. Power tools; 200a. Ride-on lawnmower; 200b. Electric drill; 200c. Chainsaw; 200d. Pruner; 200e. Hair dryer; 200f. All-terrain vehicle;

[0091] 10. Housing; 11. Airflow outlet; 12. Terminal assembly; 13. Fireproof component; 20. Cell; 21. Electrode; 21a. First type electrode; 21b. Second type electrode; 22. Cell body; 30. Support; 30a. Upper support; 30b. Lower support; 30c. Sleeve; 31. (Support end face) Opening; 32. (Support) Concave-convex stop; 33. Positioning post; 40. End cap; 41. Recessed boss; 42. Thin-walled feature; 43. (End cap) Concave-convex stop; 44. (Between end cap and support) Fastener; 50. Spacer; 51. Area divided by spacer; 61. First metal plate; 62. Second metal plate; 63 / 63a / 63 b / 63c, Exhaust channel; 64, Third metal plate; 65, Fourth metal plate; 66, Fifth metal plate; 67, Fastener (between metal plate and end cap); 70, Connecting piece; 71, First layer component; 71a, First surface; 71b, Second surface; 72, Second layer component; 72a, Overlapping portion; 73, (Connecting piece) Opening; 74, Electrode connection portion; 75, Mounting portion; 80, Heat insulation device; 81, Heat insulation component; 82, Fuse; 83, Interface board assembly; 90, Flexible circuit board / FDC board; 90a, Main circuit section; 90b, Branch circuit section; 91, Conductive layer; 91a, Through-hole pad; 92, Substrate; 93, Positioning hole;

[0092] d1, the shortest distance between the first type of electrode and the end cap; d2, the shortest distance between the second type of electrode and the end cap; d3, the end cap thickness at the location corresponding to the first type of electrode; d4, the end cap thickness at the location corresponding to the second type of electrode; d5, the thickness of the first layer element; d6, the thickness of the second layer element; d7, the shortest distance between the edge of the conductive layer and the edge of the substrate or the edge of the positioning hole. Detailed Implementation

[0093] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0094] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0095] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0096] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0097] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0098] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0099] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0100] In this application, the terms "controller," "processor," "central processing unit," "CPU," and "MCU" are used interchangeably. When using the unit "controller," "processor," "central processing unit," "CPU," or "MCU" to perform a specific function, unless otherwise stated, these functions may be performed by a single or multiple of the aforementioned units.

[0101] In this application, the terms "device," "module," or "unit" are used to describe devices that can be implemented in hardware or software to perform a specific function.

[0102] In this application, the terms “calculation,” “judgment,” “control,” “determine,” “identify,” etc., refer to the operation and process of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0103] With the development of lithium battery technology, it has been widely used in various industries. A major focus in the design process is safety, including not only the safety at the cell level but also the safety at the battery pack level. This means that in addition to improving the safety performance of the cells themselves through improvements in positive and negative electrode materials, it is even more important to consider the overall fire and explosion prevention, heat dissipation and temperature uniformity, insulation and waterproofing of the battery pack. The following detailed description of the battery pack and related solutions proposed in this application, with reference to specific embodiments and accompanying drawings, is provided in detail.

[0104] This application primarily provides a battery pack 100, which is a battery pack for power tools. It can be detachably connected to a power tool 200 to supply power to the power tool 200, and its design needs to adapt to various operating conditions of the power tool 200. (Reference) Figure 1The power tool 200 that accepts power from the battery pack 100 of this application can be of various different types, including but not limited to... Figure 1 The illustrated components include a ride-on lawnmower 200a, an electric drill 200b, a chainsaw 200c, a lawn mower 200d, a blower 200e, and an all-terrain vehicle 200f. In some embodiments, the power tools 200 powered by the battery pack 100 of this application may include handheld power tools, such as pruners and circular saws. In some embodiments, the power tools 200 powered by the battery pack 100 of this application may include benchtop tools, such as miter saws and metal cutters. In some embodiments, the power tools 200 powered by the battery pack 100 of this application may include push tools or ride-on tools, such as push lawnmowers, push snow sweepers, ride-on lawnmowers, and stand-up lawnmowers. In some embodiments, the power tools 200 powered by the battery pack 100 of this application may include outdoor wheeled tools, such as farm vehicles and golf carts. In some embodiments, the power tool 200 receiving power from the battery pack 100 of this application may include robotic tools, such as lawnmowers and snowplows. Alternatively, in some embodiments, the power tool 200 may be garden tools, such as pruning machines, hair dryers, lawnmowers, and mowers. In some embodiments, the power tool 200 may be decorating tools, such as screwdrivers, nail guns, glue guns, sanders, and circular saws. In some embodiments, the power tool 200 may be cleaning tools, such as hair dryers, snowplows, and washing machines. Alternatively, in some embodiments, the power tool 200 may be cutting tools, such as reciprocating saws, jigsaws, circular saws, and chainsaws. In some embodiments, the power tool 200 may be fastening tools, such as electric drills, screwdrivers, and hammer drills. In some embodiments, the power tool 200 may be grinding tools, such as angle grinders and sanders. In some embodiments, the power tool 200 may also be other tools, such as lights and fans. It is understandable that, provided that the characteristics are not contradictory, the power tools 200 that receive power from the battery pack 100 of this application may have more types not shown above. The aforementioned power tools 200 generally have a battery mounting part that can be detachably connected to the battery pack 100. The specific location and structure of the battery mounting part may vary between different power tools 200, and the structural arrangement of different power tools 200 is also different. Taking a ride-on lawnmower as an example, it generally has a frame, a running assembly including at least a running wheel and a running motor, and a cutting assembly including at least a blade and a cutting motor. The battery mounting part is generally located at the front or rear of the frame, which will not be described in detail.

[0105] refer to Figures 2 to 9The battery pack 100 includes a housing 10 and a plurality of battery cells 20. Each battery cell 20 is a component within the battery pack 100 that stores electrical energy. Each battery cell 20 has positive and negative electrodes 21. In some embodiments, the battery cell 20 can be a cylindrical battery, a prismatic battery, or a pouch battery. In some embodiments, the battery cell 20 can be a unitab battery, a bitab battery, a multitab battery, or a omnitab battery. In some embodiments, the battery cell 20 can be a lithium iron phosphate cell or a ternary lithium battery. In some embodiments, the battery cell 20 can also be a sodium-ion cell. In some embodiments, the characteristics of the plurality of battery cells 20 within the battery pack 100 can be different or partially different. The specific number of cells 20 in the battery pack 100 can be adjusted within a certain range. Multiple cells 20 can form one or more cell modules 100a. Within the same cell module 100a, cells 20 are connected in series, in parallel, or in a mixed series-parallel manner. Different cell modules 100a are connected in series or in parallel manner, with each cell module as a unit. Ultimately, the total positive and negative terminals of the battery pack 100 can be formed, that is, the total positive and negative terminals of the battery pack 100 that are fed by external power. They belong to the terminal assembly of the battery pack 100.

[0106] The housing 10 has an internal accommodating space, within which the plurality of battery cells 20 or one or more battery cell modules 100a are accommodated. The accommodating space generally also includes a support 30 for supporting the battery cells 20. In one alternative embodiment of this application, such as... Figures 4 to 9 As shown, the support 30 for the battery cell 20 has an end face corresponding to the position of the electrode 21 of the battery cell 20, and the end face has an opening 31 that can expose the electrode 21 of the battery cell 20. In some embodiments, the opening 31 on the end face of the support 30 corresponds one-to-one with the electrode 21 of the battery cell 20, that is, one opening 31 on the end face of the support 30 exposes one electrode 21 of the battery cell 20; in other embodiments, the opening 31 on the end face of the support 30 has a one-to-many relationship with the electrode 21 of the battery cell 20, that is, one opening 31 on the end face of the support 30 exposes multiple electrodes 21 of the battery cell 20. Meanwhile, in this embodiment, an end cap 40 is also provided in the accommodating space of the housing 10. The end cap 40 is installed on the end face of the bracket 30. The positional relationship between the battery cell 20, the bracket 30 and the end cap 40 is that multiple battery cells 20 are located on one side of the end face of the bracket 30, and the end cap 40 is installed on the other side of the end face of the bracket 30. Through the opening 31 on the end face of the bracket 30, there is a path or space for the sealant to flow between the electrode 21 of the battery cell 20 and the end cap 40.

[0107] Furthermore, in this embodiment, either the end cap 40 or the support 30 end face is provided with an isolator 50, or both the end cap 40 and the support 30 end face are provided with isolators 50. The end cap 40 and the support 30 end face are filled with sealant, which will be separated into several regions 51 defined by the isolator 50. The separated sealant will cover the electrode 21 of the cell 20 in the several regions 51. Specifically, the inner wall of the end cap 40 is mounted facing the outer wall of the end face of the bracket 30. An isolation member 50 is formed on the inner wall of the end cap 40, or the outer wall of the end face of the bracket 30, or the inner wall of the end cap 40 and the outer wall of the end face of the bracket 30. Typically, the isolation member 50 is integral with the end cap 40 or the bracket 30. In some embodiments, the isolation member 50 is an isolation rib formed on the end face of the end cap 40 or the bracket 30. In some embodiments, the isolation member 50 includes an isolation rib disposed on the outer edge of the end face of the end cap 40 or the bracket 30, which can form a common periphery of the above-mentioned several regions 51 and define the outermost periphery covered by sealant.

[0108] The battery cell 20 is located inside the end face of the bracket 30. The opening 31 of the end face of the bracket 30 penetrates the end face of the bracket 30 and corresponds to the position of the electrode 21 of the battery cell 20. The aforementioned isolator 50 can divide and separate the opening 31, that is, it can divide and separate the battery cell 20 electrode 21 exposed by the opening 31 or the position corresponding to the opening 31. In some embodiments, the opening 31 of the end face of the bracket 30 corresponds one-to-one with the battery cell 20 electrode 21. When viewed from the end face of the bracket 30, the aforementioned isolator 50 can divide multiple openings 31 or multiple battery cell 20 electrodes 21 into the same area 51. In other embodiments, the opening 31 of the end face of the bracket 30 and the battery cell 20 electrode 21 have a one-to-many relationship. When viewed from the end face of the bracket 30, the aforementioned isolator 50 can divide one opening 31 or multiple battery cell 20 electrodes 21 exposed by the opening 31 into the same area 51. The opening 31 penetrating the end face of the bracket 30 forms a path or space for the sealant to flow between the inner wall of the end cap 40 and the electrode 21 of the cell 20. However, the presence of the separator 50 isolates the flow path or space of the sealant from each other and they are not completely interconnected. Based on this, when sealant is filled between the inner wall of the end cap 40 and the end face of the bracket 30, the sealant will be separated and restricted in each region 51 by the separator 50. The sealant in different regions 51 is not interconnected. Under the restriction of the separator 50, the sealant in each region 51 covers one or more electrodes 21 of the cell 20 belonging to this region 51 through the opening 31 of the end face of the bracket 30 in this region 51.

[0109] In this embodiment, the end cap 40, together with the bracket 30, divides the electrodes 21 of multiple cells 20 into different regions 51 and separates them with sealant. The electrodes 21 of the cells 20 in each region 51 are covered by the sealant of that region 51. The creepage distance between cells 20 in different regions 51 and between the positive and negative electrodes of the cells 20 is increased, thus enhancing the waterproof capability of the battery pack 100. In addition to the electrodes 21, the cells 20 also include a cell body 22. Taking a cylindrical battery as an example, the positive and negative electrodes 21 are located at both ends of the axial direction of the cells 20, and the majority of the area between the two ends of the cells 20 is the cell body 22. In this embodiment, the electrodes 21 of the cells 20 are covered with sealant, while at least part of the cell body 22 is not covered by sealant, thereby reducing the amount of sealant used and not affecting the heat dissipation of the cells 20.

[0110] In some embodiments, the division of region 51 of the separator 50 is based on the electrical connection relationship between the cells 20. Multiple cells 20 electrodes 21 with electrical connection relationship can be divided into the same region 51, while cells 20 electrodes 21 without electrical connection relationship are located in different regions 51, so as to reasonably increase the creepage distance of the cells 20 and improve the waterproof performance of the battery pack 100. In some embodiments, multiple cells 20 electrodes 21 within the same region 51 are electrically connected by a connecting piece 70. Specifically, the series and parallel connection between cells 20 within the battery pack 100 can be achieved through the connecting piece 70. Taking the positive and negative electrodes 21 of a cylindrical battery located at opposite ends of the axial direction as an example, the bracket 30 and end cap 40 can be arranged along the axial direction of the cell 20. Multiple cells 20 within the battery pack 100 are connected in parallel. The positive electrodes 21 of the parallel cells 20 are exposed through the end face opening 31 of the bracket 30 and electrically connected by the same connecting piece 70. The end cap 40 and / or the isolator 50 on the end face of the bracket 30 can surround the positive electrodes 21 of the parallel cells 20 to the same region 51 and then coat the region 51 with adhesive.

[0111] In some embodiments, multiple electrically connected cell electrodes 21 are exposed through the same opening 31, and the connecting piece 70 can connect the multiple cell electrodes 21 in the opening 31 of the bracket 30; in other embodiments, the multiple electrically connected cell electrodes 21 are each exposed through different openings 31, and the connecting piece 70 can connect the multiple cell electrodes 21 via multiple bracket openings 31. Furthermore, the bracket 30 can also serve to fix the connecting piece 70, and the connecting piece 70 can be fixed to the bracket 30 by bolts, screws, etc., to maintain stability.

[0112] In some embodiments, the separator 50 of the end cap 40 and / or the bracket 30 is disposed around the outer periphery of the connecting piece 70, thereby reducing unnecessary adhesive coverage while dividing the electrically connected electrodes 21 of the cell 20 into the same region 51.

[0113] In some embodiments, the sealant filled between the end cap 40 and the end face of the bracket 30 is a sealing material whose shape can change with the sealing surface and has a certain degree of adhesion. The sealant is not very fluid. In this embodiment, it can seal the electrode 21 of the cell 20 after being pressed by the end cap 40. The sealant may include one or more of single-component silicone, two-component potting compound, expanding adhesive / foaming compound. It is understood that the path and space for the expansion of the adhesive can be designed in advance.

[0114] In some embodiments, the sealant applied to the battery pack 100 should have good thermal conductivity to avoid adversely affecting the heat dissipation of the battery pack 100. Specifically, the thermal conductivity of the applied sealant can be greater than or equal to 0.3 W / (m·K), preferably greater than or equal to 0.4 W / (m·K), and in some embodiments, the thermal conductivity of the sealant is approximately 0.5 W / (m·K).

[0115] In some embodiments, the end cap 40 may include flame-retardant material to improve the fire and explosion protection performance of the battery pack 100. In some embodiments, the end cap 40 is a two-in-one component of a plastic part and a metal plate, as detailed below.

[0116] In some embodiments, to fully ensure the waterproof capability of the battery pack 100, a sealed connection can be achieved between the end cap 40 and the end face of the bracket 30. That is, no water leakage gap is left at the installation location of the end cap 40 and the end face of the bracket 30. In some embodiments, the end cap 40 and the end face of the bracket 30 are coupled through concave-convex stops 32 and 43. The concave-convex stops can be a single stop or a double stop. In some embodiments, the aforementioned isolation member 50 can also be implemented in the form of concave-convex stops. In addition, the assembly of the bracket 30 itself can also be achieved through concave-convex stop coupling to prevent the battery cell 20 supported inside the bracket 30 from being exposed to water or leakage. For example, the bracket 30 is assembled from multiple components (upper bracket 30a, sleeve 30c, lower bracket 30b) along the axial direction of the battery cell 20, and they are coupled and sealed with each other through concave-convex stops.

[0117] In other embodiments, the concave and convex stops on the end faces of the end cap 40 and the bracket 30 are further provided with sealing materials such as soft rubber to enhance the waterproof performance. The soft rubber may be sleeved on the convex stop or embedded in the concave stop. Specifically, concave and convex stops (the end face of the bracket 30 may be provided with a groove, and the end cap 40 may be provided with a rib) may be provided on the outer edge of the area covered by the end cap 40 after installation and filled with soft rubber, so as to work with the sealant filling the end face of the end cap 40 and the bracket 30 to finally form a good sealing environment.

[0118] In another alternative implementation of this application, such as Figures 7 to 9As shown, similar to the previous description, the bracket 30 supporting the battery cell 20 inside the housing 10 has an end face corresponding to the position of the electrode 21 of the battery cell 20. This end face has an opening 31 that exposes the electrode 21 of the battery cell 20. An end cap 40, mounted to the end face of the bracket 30, is also provided inside the housing 10. Sealant is filled between the end cap 40 and the end face of the bracket 30, covering multiple electrodes 21 of the battery cell 20. In this embodiment, the multiple electrodes 21 of the battery cell 20 covered by the sealant may include a first type of electrode 21a and a second type of electrode 21b. The shortest distance d1 between the first type of electrode 21a and the end cap 40 is smaller than the shortest distance d2 between the second type of electrode 21b and the end cap 40. This embodiment reduces the thickness of the sealant covering some of the electrodes 21 of the battery cell 20, so that when thermal runaway occurs in the battery pack 100, the airflow and flame have a breakthrough point for escape, avoiding a more serious explosion. It is understandable that due to differences in the structure and packaging process of the positive and negative electrodes 21 of the cell 20, the thickness of the sealant covering the positive electrode 21 of the cell 20 may be different from the thickness of the sealant covering the negative electrode 21 of the cell 20. However, in this embodiment, multiple cells 20 supported by the same support 30 end face have the same axial height. Taking a cylindrical lithium battery with the positive and negative electrodes 21 located at opposite ends of the axial direction and the positive electrode 21 protruding more than the negative electrode 21 as an example, the distance from the highest point of the positive electrode 21 of the cell 20 exposed through the opening 31 of the support 30 end face along the axial direction and the lowest point of the negative electrode 21 of the cell 20 along the axial direction to a plane perpendicular to the central axis of the cell 20 is the same. Therefore, those skilled in the art should be able to understand the difference between this embodiment and the conventional case.

[0119] In some embodiments, adapted to the cell 20 structure, to facilitate airflow and flame exhaust and pressure relief, the first type of electrode 21a corresponding to the reduced sealant thickness is the positive electrode 21 of the cell 20, while the second type of electrode 21b is the negative electrode 21 of the cell 20. Multiple cell 20 electrodes 21 corresponding to the same end face include the first type of electrode 21a and the second type of electrode 21b. That is, the cell 20 electrodes 21 exposed by the opening 31 on the end face of the same support 30 include both positive and negative electrodes 21. In this case, at least some of the cells 20 are connected in series. In other embodiments, taking a cylindrical battery with positive and negative electrodes 21 located at opposite ends of the axial direction of the cell 20 as an example, if all the electrodes 21 of the cell 20 exposed by the end face opening 31 of the bracket 30 are positive electrodes 21 or all are negative electrodes 21, then the electrodes 21 of the cell 20 covered by the sealant filling between the bracket 30 and one end cap 40 are first type electrodes 21a, that is, positive electrodes 21 of the cell 20, and the electrodes 21 of the cell 20 covered by the sealant filling between the bracket 30 and the other end cap 40 are second type electrodes 21b, that is, negative electrodes 21 of the cell 20. The shortest distance from the positive and negative electrodes 21 to the end cap 40 is not the same, and the shortest distance from the positive electrode 21 to the end cap 40 on its side is smaller. This situation is also consistent with the concept of this embodiment.

[0120] In some embodiments, reducing the minimum distance between the first type of electrode 21a and the end cap 40, i.e., reducing the thickness of the sealant covering the electrode 21 of the battery cell 20, is achieved by designing a recess at the location corresponding to the position of the end cap 40 and the first type of electrode 21a, or by making the recess depth at the location corresponding to the position of the end cap 40 and the first type of electrode 21a greater than the recess depth at the location corresponding to the position of the second type of electrode 21b. Specifically, a recessed protrusion 41 can be formed on the part of the end cap 40 facing the first type of electrode 21a to get closer to the first type of electrode 21a, or recessed protrusions 41 can be formed on the parts of the end cap 40 facing the first and second types of electrodes 21a and 21b, with the recessed protrusion 41 at the location corresponding to the first type of electrode 21a sinking deeper towards the electrode, thereby shortening the distance between them.

[0121] In some embodiments, in addition to reducing the thickness of the sealant covering the electrode 21 to achieve pressure relief and explosion prevention, the material thickness of the portion of the end cap 40 corresponding to the position of the first type of electrode 21a can also be reduced, so that the thickness d3 of the portion of the end cap 40 corresponding to the position of the first type of electrode 21a is less than the thickness d4 of the portion corresponding to the position of the second type of electrode 21b. Specifically, the central local area 42 of the recessed protrusion 41 of the end cap 40 can be further made thin-walled to reduce the thickness of the end cap 40 at this position. This central local area 42 can be roughly aligned axially with the position of the explosion-proof valve to facilitate the discharge and pressure relief of airflow and flame in the event of thermal runaway.

[0122] In some embodiments, the end cap 40 can be fixedly installed to the end face of the bracket 30 by fasteners, specifically, by bolt and nut. The fixing of the end cap 40 can ensure that the shortest distance from the first and second type electrodes 21a and 21b to the end cap 40 meets the expectations to allow the thermal runaway gas flow and flame to be discharged and depressurized. It can also ensure that the sealant covers the electrode 21 of the cell 20 in sections when the end cap 40 and / or the bracket 30 are designed with an isolator 50 to increase the creepage distance and improve the waterproof performance. As mentioned above, the isolator 50 divides the multiple electrode 21 of the cell 20 that have electrical connection into the same area 51. The electrode 21 of the cell 20 in different areas 51 do not have electrical connection. The same area 51 can include both the first type electrode 21a and the second type electrode 21b, or the same area 51 can include only the first type electrode 21a or the second type electrode 21b.

[0123] In some embodiments, the end cap 40 and sealant design can be provided next to the electrode 21 of at least one side of the cell 20, or, the two sides of the cell 20 can each be provided with a bracket 30 with an opening 31 on the end face exposing the electrode 21 and an end cap 40 installed on the end face of the bracket 30, and the end face of the bracket 30 and the end cap 40 are filled with sealant. Further, at least one of the bracket 30 end face and the end cap 40 is provided with an isolation member 50, and / or, the shortest distance between the first and second type electrodes 21a and 21b and the end cap 40 is not equal.

[0124] Following the preceding text, this application also provides an assembly method for a cell module 100a, used to assemble the cell module 100a within the battery pack 100 described above, such as... Figure 28 As shown, the specific steps may include the following:

[0125] S02, multiple battery cells 20 are mounted to a bracket 30, wherein each battery cell 20 has an electrode 21, the bracket 30 has an end face corresponding to the position of the electrode 21 of the battery cell 20, and the end face has an opening 31 that exposes the electrode 21 of the battery cell 20.

[0126] S04, the connecting piece 70 is welded to the plurality of electrodes 21 through the opening 31 of the end face exposing the electrode 21 of the cell 20;

[0127] S06, a sealant is applied to the surfaces of the connecting piece 70 and the plurality of electrodes 21;

[0128] S08, install the end cap 40 onto the end face of the bracket 30, and squeeze the sealant onto the end face.

[0129] Specifically, following the previous text, the bracket 30 of the battery pack 100 has an end face that corresponds to the electrode 21 of the cell 20 and has an opening 31 that exposes the electrode 21 of the cell 20. When assembling the cell module 100a, firstly, multiple cells 20 need to be installed onto the bracket 30. After the cells 20 are installed, the electrodes 21 of these cells 20 will be exposed through the opening 31 on the end face of the bracket 30. These multiple cells 20 installed together constitute a cell module 100a within the battery pack 100. Alternatively, the battery pack 100 may include more than one cell module 100a, such as two cell modules 100a. In this case, the multiple cell modules 100a can be assembled separately. In some embodiments, the bracket 30 may have a limiting structure that defines the position of the supported battery cell 20, or the end face opening 31 of the bracket 30 may also be regarded as a limiting structure. During assembly, multiple battery cells 20 can be installed onto the bracket 30 according to the limiting structure. In some embodiments, the bracket 30 may be assembled by mating upper and lower brackets (upper bracket 30a, sleeve 30c, lower bracket 30b). Taking a cylindrical battery as an example, multiple bracket 30 components may be assembled along the axial direction of the battery cell 20. During assembly, multiple battery cells 20 may be installed into the bracket 30 to be assembled. After the battery cells 20 are arranged, the bracket 30 components are mated and assembled.

[0130] After the battery cell 20 of the battery cell module 100a is installed onto the end face of the bracket 30, the electrodes 21 of the battery cell 20 that need to be electrically connected are welded through the connecting piece 70 according to the series and parallel connection relationship between the battery cells 20. The battery cell 20 electrodes 21 that can be electrically connected by the same connecting piece 70 include parallel positive electrodes 21, parallel negative electrodes 21, and series positive and negative electrodes 21. The multiple battery cell 20 electrodes 21 electrically connected by the same connecting piece 70 have the same potential. The multiple battery cell 20 electrodes 21 are exposed through one or more openings 31 on the end face of the bracket 30. The connecting piece 70 can be welded to multiple electrodes 21 through multiple openings 31, and the multiple battery cell 20 electrodes 21 to be electrically connected are each spot welded to the connecting piece 70. In some embodiments, the connecting piece 70 and the battery cell 20 electrodes 21 are welded by laser welding. In some embodiments, when the connecting piece 70 welds the electrodes 21 through multiple openings 31, the non-opening 31 positions on the end face of the bracket 30 covered by the connecting piece 70 can be fixed to the bracket 30 with bolts, nuts, etc.

[0131] After the battery cell 20 is installed onto the bracket 30 and electrically connected by welding with the connecting piece 70, sealant can be applied to the surface of the connecting piece 70 and the electrode 21 of the battery cell 20. Then, the end cap 40 is installed onto the end face of the bracket 30. The end cap 40 presses down on the end face of the bracket 30 that has been covered with sealant, so that the sealant is squeezed to effectively cover the target component and further fill the water-permeable gaps, thereby significantly improving the waterproof capability of the battery pack 100. Along the direction from the outside to the inside, under the pressure of the end cap 40, the sealant will sequentially cover the connecting piece 70, the welding point of the connecting piece 70 and the electrode 21, and the electrode 21 of the battery cell 20. At the same time, the sealant can fill the opening 31 on the end face of the bracket 30, including the gap between the bracket 30 and the electrode 21 of the battery cell 20 and the gap between the bracket 30 and the side of the battery cell 20, etc., which can be filled by the sealant. After pressing, it can be fixed to the end face of the bracket 30 with bolts or other fasteners.

[0132] In some embodiments, following the foregoing, the end cap 40 and / or the bracket 30 end face are formed with an isolator 50. The sealant covering the connecting piece 70 and the electrode 21 of the cell 20 can be separated into several different areas 51 by the isolator 50 during the process of installing the end cap 40 to the end face of the bracket 30, thereby increasing the creepage distance in the battery pack 100 and improving the waterproof performance.

[0133] In some embodiments, following the foregoing, the portion of the end cap 40 corresponding to the position of the electrode 21 of the battery cell 20 is adjusted in design. This allows the sealant, compressed by the end cap 40, to fill the space between the end cap 40 and the opening 31 of the end face of the bracket 30 after the end cap 40 is installed on the bracket 30. The thickness of the sealant on different electrodes 21 is adjusted during assembly, resulting in varying distances from the electrode 21 of the battery cell 20 to the end cap 40. This allows for a pressure relief breakthrough point for thermal runaway airflow and flame. In some embodiments, a recessed protrusion 41 is provided on the end cap 40 corresponding to the position of the first type of electrode 21a, such as the positive electrode 21 of the battery cell 20, or the material thickness is reduced. This makes the shortest distance between the first type of electrode 21a and the end cap 40 smaller than the shortest distance between other battery cell 20 electrodes 21 (second type of electrode 21b) and the end cap 40. The sealant filling the space between the end cap 40 and the first type of electrode 21a is thinner, allowing airflow and flame to break through the aforementioned portion of the end cap 40 and escape when the battery pack 100 experiences thermal runaway, thus preventing explosion.

[0134] The aforementioned embodiments involving end caps, brackets, and sealant between them optimize the waterproof design near the cell electrodes within the battery pack. The installation result from the end cap to the bracket, as well as the squeezing action during assembly, ensures that the sealant covers the cell electrodes exposed by the opening and further fills the gaps between the bracket and the cell electrode surfaces and the cell sides. The separator further increases the creepage distance within the battery pack. Adjustments to the end cap structure and thickness further improve the pressure relief function of the battery pack under this design. The aforementioned embodiments can meet the increasingly stringent safety requirements of power tool battery packs and adapt to the working conditions of some power tools in wet environments.

[0135] This application also provides another embodiment for improving the thermal runaway pressure relief capability of the battery pack 100, which includes a housing 10 constituting its main body, and an internal accommodating space formed by the housing 10 accommodating the battery cells 20 and a support 30 supporting the battery cells 20. Furthermore, referring to... Figures 17 to 19 The battery pack 100 also includes at least a first metal plate 61 and a second metal plate 62, which are also housed within the battery pack 100 housing 10. The first metal plate 61 is arranged with its plane approximately perpendicular to the central axis of the cell 20, and the second metal plate 62 is arranged with its plane approximately parallel to the plane of the first metal plate 61. In other words, the first and second metal plates 61 and 62 are parallel to and perpendicular to the central axis of the cell 20. Meanwhile, the first metal plate 61 has an opening 31, the position of which corresponds to the electrode 21 of the cell 20 so that the airflow ejected from the electrode 21 when the cell 20 experiences thermal runaway can pass through. The first and second metal plates 61 and 62, which are arranged in parallel, are located on the same side of the cell 20 in the axial direction. Together with the opening 31, they can form an exhaust channel 63 next to the electrode 21 of the cell 20. The airflow entering from the opening 31 of the first metal plate 61 passes through the interplate exhaust channel 63 under the guidance and restriction of the first and second metal plates 61 and 62, and is finally discharged outside the battery pack 100 housing 10, thus realizing the function of pressure relief and explosion prevention.

[0136] Specifically, multiple battery cells 20 are arranged side-by-side within the battery pack 100 and supported by the same bracket 30. The first metal plate 61 may have multiple openings 31, the positions of which correspond one-to-one with the positions of the electrodes 21 of the multiple battery cells 20. That is, during thermal runaway, the airflow ejected from the electrodes 21 of each battery cell 20 has an opening 31 closest to that electrode 21 through which it can pass, providing better guidance. Taking a cylindrical battery as an example, multiple battery cells 20 can be arranged parallel to each other and clustered together. The electrodes 21 of these multiple battery cells 20 are approximately located on the same plane. The first and second metal plates 61 and 62 can be arranged approximately parallel to the plane where the electrodes 21 of the battery cells 20 are located. The openings 31 on the first metal plate 61 can be opened one-to-one towards the positions of each electrode 21. The shape of the openings 31 on the first metal plate 61 can be a regular shape, such as a circle, or an irregular shape. In some embodiments, the correspondence between the openings 31 on the first metal plate 61 and the electrodes 21 of the battery cells 20 can also be one-to-many.

[0137] In some embodiments, the first metal plate 61 and / or the second metal plate 62 are made of alloy materials, including but not limited to aluminum alloy materials. The metal plate materials should have good fire resistance and heat dissipation properties. The materials used for the first metal plate 61 and the second metal plate 62 may be the same or different. In some embodiments, the first metal plate 61 and / or the second metal plate 62 are also mixed with other materials that can improve fire resistance in addition to the alloy materials.

[0138] The battery pack 100 housing 10 is generally provided with an airflow outlet 11 for heat dissipation, which can provide air cooling or natural heat dissipation for the battery pack 100 under normal circumstances. In the event of thermal runaway, under the guidance of the exhaust channel 63 between the first and second metal plates 61 and 62, the relevant airflow and flame will reach the aforementioned airflow outlet 11 or part of the airflow outlet 11. In some embodiments, to avoid damage to the housing 10, strengthen the relevant structural strength, and ensure the smooth discharge of thermal runaway airflow and flame, such as... Figures 17 to 19 As shown, the airflow outlet 11, which is connected to the exhaust channel 63 between the first and second metal plates 61 and 62, is provided with a fireproof component 13. The fireproof component 13 is made of a material different from that of the housing 10 and should have good fireproof and heat dissipation performance. Specifically, the housing 10 can be mainly made of engineering plastics, and the fireproof component 13 can be made of a metal material such as aluminum alloy. In some embodiments, the fireproof component 13 provided at the airflow outlet 11 can be a metal plate or metal mesh with an opening corresponding to the position of the airflow outlet 11.

[0139] In some embodiments, in addition to the first and second metal plates 61 and 62, a greater number of metal plates may be arranged in the battery pack 100, wherein a pair of metal plates may form an exhaust channel 63. Multiple cells 20 arranged in parallel within the battery pack 100 can form a cell module 100a. Taking a cylindrical battery with the electrodes 21 of the cells 20 at both ends of the axial direction as an example, a cell module 100a can include multiple cells 20 arranged in parallel. The electrodes 21 of these multiple cells 20 are arranged on both sides of the cell module 100a. At least one side of the cell module 100a can be provided with the aforementioned first and second metal plates 61 and 62 so that the airflow and flame when the electrode 21 of one side of the cell 20 thermally runs away can leave the housing 10 through the exhaust channel 63a. Furthermore, a third and fourth metal plates 64 and 65 can be provided on the other side of the cell module 100a to form another exhaust channel 63b on the other side of the cell 20 so that the airflow and flame when the electrode 21 of the cell 20 on the other side of the cell 20 can be discharged. When the battery pack 100 contains more than one cell module 100a, each cell module 100a can be configured with the aforementioned paired metal plates. One cell module 100a can be configured with 0, 2, or 4 metal plates, forming 1 or 2 exhaust channels 63. In some embodiments, when the cell 20 electrodes 21 of two cell modules 100a are placed opposite each other to form their respective exhaust channels 63, they can share a single metal plate. Specifically, the positive and negative electrodes 21 of the cell 20 electrodes 21 are located on the left and right sides of the cell module 100a, respectively. The right electrode 21 of one cell module 100a is adjacent to the left electrode 21 of another cell module 100a. The exhaust channel 63b serving the right electrode 21 is constructed by the third and fourth metal plates 64 and 65, and the adjacent exhaust channel 63a serving the left electrode 21 of the other cell module 100a can be constructed by the fourth and fifth metal plates 65 and 66. The two share the fourth metal plate. For the relevant features of other metal plates, please refer to the descriptions of the embodiments of the first and second metal plates 61 and 62 above, which will not be repeated here.

[0140] Following the previous description, in some embodiments, to enhance the pressure relief and explosion-proof capability of the battery pack 100, the above-mentioned end cap 40 sealing solution and metal plate solution can be combined. The end face of the bracket 30 is provided with an opening 31 to expose the electrode 21 of the supported cell 20. The end cap 40 is installed on the end face of the bracket 30 and the space between them is filled with a sealant that can cover the exposed electrode 21 of the cell 20. Then, the battery pack 100 can be optionally provided from the outside to the inside as follows: the housing 10 and its airflow outlet 11, the fireproof component 13 on the inner or outer wall of the housing 10 corresponding to at least part of the airflow outlet 11, the second metal plate 62, the first metal plate 61 and its opening 31 corresponding to the electrode 21 of the cell 20, the end cap 40 and its pressure relief design corresponding to the electrode 21 of the cell 20, the sealant, the connecting piece 70, the bracket 30 and its opening 31 corresponding to the electrode 21 of the cell 20, and the cell 20 and its electrode 21. In other words, when thermal runaway occurs in cell 20, the airflow or flame ejected from its electrode 21 will first pass through the opening 31 of bracket 30, break through the sealant, and then, due to the design of the end cap 40 sinking protrusion 41 or the material thickness reduction, such pressure relief points that are easier to break through will break through the end cap 40, and then reach the first metal plate 61 and pass through its opening 31, enter the exhaust channel 63 between the first and second metal plates 61 and 62, and under the guidance of the channel, reach the airflow outlet 11 of the housing 10, and finally be discharged outside the housing 10 of battery pack 100 through the airflow outlet 11 protected and supported by the fireproof component 13.

[0141] In some embodiments, the planes on which the end cap 40, the first metal plate 61, and the second metal plate 62 are located are approximately parallel. Specifically, assuming that the cylindrical batteries are arranged in parallel and concentrated manner, and the electrodes 21 at both ends of the cell 20 are located on two planes, the end cap 40, the first metal plate 61, and the second metal plate 62 can be arranged approximately parallel to the plane on which one side of the cell 20 electrode 21 is located. In some embodiments, the positions of the opening 31 of the bracket 30, the recessed protrusion 41 or the material thickness reduction portion 42 of the end cap 40, and the opening 31 of the first metal plate 61 correspond to each other, for example, they overlap or at least partially overlap in the airflow jet direction along the axial direction of the cell 20. In some embodiments, such as Figure 17 As shown, the first metal plate 61 is installed on the end cap 40, or the first metal plate 61 and the end cap 40 are designed as a two-in-one component. Specifically, the first metal plate 61 can be an insert of the plastic end cap 40, so that the end cap 40 with the metal plate containing the opening 31 has both waterproof and fireproof capabilities, and the melted plastic will not stick to the outer second metal plate 62 and interfere with the exhaust passage 63 when thermal runaway occurs.

[0142] The aforementioned embodiments involving metal plates and exhaust channels improve the battery pack's ability to relieve pressure, prevent explosions, and prevent fire. The bimetallic plate, located on the same side as the cell electrodes, guides the thermal runaway airflow out of the battery pack through openings on the plate and channels between the plates. The flame-retardant and cooling properties of the metal plate ensure that the opening and channel structure is reliable, not easily damaged, and allows the airflow to effectively dissipate heat within the channels, thereby preventing the spread of fire. The combination of embodiments such as end caps further ensures waterproof performance, improving the safety of the battery pack in multiple ways.

[0143] This application also provides an embodiment for improving the high current transmission and heat dissipation capabilities of a battery pack 100. The battery pack 100 includes a housing 10 constituting its main exterior structure. The internal space formed by the housing 10 accommodates one or more battery cell modules 100a. Each battery cell module 100a includes at least a plurality of battery cells 20 and connecting pieces 70 electrically connecting the electrodes 21 of these battery cells 20. In this embodiment, referring to… Figures 10 to 16 The connecting piece 70 includes at least a first layer element 71 and a second layer element 72, the first layer element 71 and the second layer element 72 at least partially overlap, and the thickness d5 of the first layer element 71 is less than 0.5 mm, and the thickness d6 of the second layer element 72 is greater than or equal to the thickness d5 of the first layer element 71.

[0144] Specifically, the battery cells 20 in the battery pack 100 are connected by connecting pieces 70, and the current is conducted through the connecting pieces 70. As the expectations for the power and other performance of the power tool 200 increase, the requirements for the overcurrent and temperature rise of the connecting pieces 70 of the battery pack 100 for the power tool 200 also increase accordingly. Although increasing the cross-sectional area of ​​the connecting pieces 70 through which the current passes can reduce the connection resistance and improve the overcurrent and temperature rise capabilities, the limited space inside the battery pack 100 and the arrangement of other components must also be considered. At the same time, an excessively thick connecting piece 70 will also make it difficult to weld to the electrode 21 of the battery cell 20. Therefore, the connecting piece 70 can be designed as a multi-layer component structure, and the thickness of each layer and the overlapping part 72a of the multi-layer components can be limited. In this embodiment, the first layer element 71 ensures basic current transmission, and its thickness is less than or equal to 0.5 mm to facilitate welding with the electrode 21 of the cell 20. The second layer element 72, based on the first layer element 71, can collaboratively enhance the overcurrent and temperature rise performance of the connecting piece 70. The thickness of the second layer element 72 is greater than or equal to that of the first layer element 71, and the second layer element 72 at least partially covers the first layer element 71. In some embodiments, the thickness of the first layer element 71 is less than or equal to 2 mm, and the thickness of the second layer element 72 is greater than that of the first layer element 71, and the second layer element 72 at least partially covers the first layer element 71. Compared with the previous embodiment, the thickness of the first layer element 71 is increased, which may impose certain requirements on the welding process between the connecting piece 70 and the electrode 21, such as requiring laser welding.

[0145] like Figure 11 As shown, the first layer element 71 of the connecting piece 70 has a first surface 71a and a second surface 71b. The first surface 71a is in direct contact with the electrode 21 of the battery cell 20 to achieve electrical connection to the battery cell 20, and the second surface 71b is at least partially covered by the second layer element 72. The thickness d5 of the first layer element 71 is defined as the distance between its first and second surfaces 71a and 71b. The second layer element 72 of the connecting piece 70 has a third surface and a fourth surface, and the thickness d6 of the second layer element 72 is defined as the distance between its third and fourth surfaces. In some embodiments, the thickness of the first and second layer elements 71 and 72 is constant, the spacing between the first and second surfaces 71a and 71b and the spacing between the third and fourth surfaces are all constant values, and the spacing between the third and fourth surfaces is greater than or equal to the spacing between the first and second surfaces 71a and 71b. In other embodiments, the thickness of the first layer element 71 is not uniform and / or the thickness of the second layer element 72 is not uniform, the spacing between the first and second surfaces 71a and 71b and the spacing between the third and fourth surfaces are not constant values, and the maximum value of the spacing between the third and fourth surfaces is greater than or equal to the maximum value of the spacing between the first and second surfaces 71a and 71b. In some embodiments, it is assumed that the third surface of the second layer element 72 overlaps with the second surface 71b of the first layer element 71, and the surface area of ​​the second surface 71b of the first element can be greater than or equal to the surface area of ​​the third surface of the second layer element 72. It is understandable that the surface or overlapping portion 72a of a multilayer element is viewed from two different perspectives, as is the thickness of each element or the cross-section through which current flows. If an undisturbed element is considered as a horizontally placed flat plate, the surface or overlapping portion can be viewed from a top view or a bottom view, while the thickness or cross-section is viewed from other perspectives.

[0146] In some embodiments, the thickness d5 of the first layer element 71 is less than or equal to 0.5 mm, and the thickness d6 of the second layer element 72 is greater than d5 and greater than or equal to 0.5 mm. In one embodiment, the thickness d5 of the first layer element 71 is approximately 0.25 mm, and the thickness d6 of the second layer element is approximately 0.5 mm. In one embodiment, the thickness d5 of the first layer element 71 is approximately 0.25 mm, and the thickness d6 of the second layer element 72 is approximately 1 mm. In some embodiments, the thickness d5 of the first layer element 71 is less than or equal to 2 mm, and the thickness d6 of the second layer element 72 is greater than d5 and greater than or equal to 1 mm. Preferably, the thickness d6 of the second layer element 72 is greater than or equal to 1.2 mm, or greater than or equal to 1.5 mm, or greater than or equal to 2 mm.

[0147] In some embodiments, along the current direction, the proportion of length occupied by the first layer element 71 in the connecting piece 70 is less than or equal to the proportion of length occupied by the second layer element 72. The length occupied by the second layer element 72 includes the length occupied by the second layer element 72 alone and the length occupied by the first and second layer elements 71 and 72 together. That is, the length of the second layer element 72 along the current direction, referring to the resistance formula R∝ρ*l / A (ρ is the resistivity of the material, l is the length, and A is the cross-sectional area). Figures 26 to 27 By adjusting the ratio rather than increasing the total length of the connecting piece 70, the resistance of the connecting piece 70 is not increased. Instead, the majority of the current-carrying capacity of the connecting piece 70 is handled by the thickened second-layer element 72 or by the combined first and second-layer elements 71 and 72. This effectively improves the overcurrent and temperature rise capabilities of the connecting piece 70. Specifically, as... Figure 13 As shown, taking two first and second layer elements 71 and 72, which are rectangular in top view, as an example, placed in the same direction and overlapping, assuming that the current flows along the longitudinal direction of the rectangle, the length occupied by the second layer element 72 is the longitudinal length of the second layer element 72, and the length occupied by the first layer element 71 alone is the difference between the longitudinal length of the first layer element 71 and the length of the overlapping part 72a, the latter being less than the former.

[0148] In some embodiments, the first layer element 71 and the second layer element 72 are joined by welding. Specifically, they can be joined by fusion welding methods such as laser welding, or by pressure welding methods such as resistance welding. The overlapping portion 72a of the first and second layer elements 71 and 72 can achieve surface contact, that is, the second surface 71b of the first layer element 71 is in contact or partially in contact with the second layer element 72. In some embodiments, the first layer element 71 and the second layer element 72 are made of the same material to facilitate welding. Specifically, the first and second layer elements 71 and 72 can both be made of copper-nickel composite material. In other embodiments, refer to... Figure 26 , Figure 27 As shown, the first layer element 71 and the second layer element 72 can be made of different materials. The second layer element 72 can be made of a material with higher thermal conductivity and / or electrical conductivity, thereby significantly improving the performance of the connecting piece 70. Specifically, the first layer element 71 can be made of copper-nickel composite material, while the second layer element 72 can be made of pure copper, i.e., industrial pure copper, or further, the second layer element 72 can be made of tin-plated pure copper. In some embodiments, the first and second layer elements 71 and 72 are made of the same material but with different thicknesses, and the second layer element 72 is thicker; in some embodiments, the first and second layer elements 71 and 72 are made of different materials and have the same or different thicknesses, and the second layer element 72 has better thermal conductivity and / or electrical conductivity; in some embodiments, the first and second layer elements 71 and 72 are made of the same material and have the same thickness, and they can be formed by folding the same material.

[0149] In some embodiments, such as Figure 14 , Figure 15 As shown, a connecting piece 70 is folded to form the first layer element 71 and the second layer element 72. That is, the first and second layer elements 71 and 72 are originally different parts of the same connecting piece 70, but after folding, they are located in different layers. In this case, the first and second layer elements 71 and 72 are already interconnected. The first and second layer elements 71 and 72, which have changed position after folding, can also be reinforced by welding. In this embodiment, the first layer element 71 and the second layer element 72 are made of the same material and can have the same thickness, but this makes the connecting piece 70 design easier to implement in terms of manufacturing process.

[0150] In some embodiments, the connecting piece 70 is disposed along the side wall of the cell module 100a within the battery pack 100. Specifically, multiple cells 20 of the cell module 100a can be assembled and supported together by the bracket 30 and form a whole in appearance. The cell module 100a can form part of its own side wall with the outer wall of the bracket 30. The connecting piece 70 can be disposed along or partially along the outer wall of the bracket 30. In the case where the connecting piece 70 is folded, it can also be disposed to wrap around the edge and / or corner of the bracket 30.

[0151] In some embodiments, such as Figure 4 , Figures 17 to 19 As shown, the overlapping portion 72a of the second layer element 72 or the first layer element 71 and the second layer element 72 in the connecting piece 70 is provided in the part of the connecting piece 70 where the current of multiple cells is collected and / or the part where the current transitions between cell modules is performed. Specifically, assuming that multiple cell electrodes 21 are electrically connected through the same connecting piece 70, the connecting piece 70 includes, in its overall structure, a branch section connected to one or more cell electrodes 21 and a main circuit section connected to the positive and negative terminals of the battery pack 100. The overlapping portion 72a of the first and second layer elements 71 and 72 can be provided on the main circuit of the connecting piece 70; or, assuming that the battery pack 100 contains multiple cell modules 100a, some connecting pieces 70 include portions that realize the electrical connection of different cell modules 100a. The overlapping portion 72a of the first and second layer elements 71 and 72 can be provided on the portion of the connecting piece 70 that is connected to other cell modules 100a. In some embodiments, the overlapping portion 72a of the first and second layer elements 71, 72 will at least not cover the cell 21 of the cell 20. The above embodiments can more specifically optimize the design of the high current and high temperature rise parts of the connecting piece 70, and the welding between the electrode 21 and the connecting piece 70 / the first and second layer elements 71, 72 is allowed by the relevant processes.

[0152] Following the preceding text, in some embodiments, to comprehensively improve the safety of the battery pack 100, the aforementioned sealant solution and connecting piece 70 solution can be combined. A bracket 30 supporting the cell module 100a or cell 20 is provided inside the battery pack 100 housing 10. The bracket 30 has an opening 31 on its end face exposing the electrodes 21 of the supported cell 20. The connecting piece 70 can electrically connect to the exposed electrodes 21 of the cell 20 through the opening 31. The opening 31 on the end face of the bracket 30 is filled with sealant to cover the connecting piece 70 and the connected electrodes 21 of the cell 20. Furthermore, an end cap 40 installed to the end face of the bracket 30 is also provided inside the battery pack 100 housing 10. Sealant is filled between the end cap 40 and the end face of the bracket 30, allowing the sealant to evenly and effectively cover the connecting piece 70 and the connected electrodes 21 of the cell 20 during the installation of the end cap 40. In some embodiments, such as... Figures 10 to 15 As shown, the connecting piece 70 has an opening 73. When the sealant fills the opening 31 on the end face of the bracket 30, or further when the end cap 40 is installed on the end face of the bracket 30, the sealant can flow through the opening 73 of the connecting piece 70 to the electrode 21 of the battery cell 20 due to gravity and compression, thereby covering the contact point between the connecting piece 70 and the electrode 21 of the battery cell 20 and the end face of the electrode 21 of the battery cell 20, and thus achieving the sealing and waterproofing of the connecting piece 70 and the electrode 21 of the battery cell 20. Specifically, the opening 73 on the connecting piece 70 may include a groove between the two solder joints of the connecting piece 70 and the electrode 21, as well as an opening near the solder joint. The opening 73 serves two purposes: first, to prevent current from passing directly between the solder joints without passing through the battery cell; and second, to help the sealant cover the electrode of the battery cell.

[0153] In some embodiments, such as Figure 12 As shown, with the electrical connection remaining unchanged, the proportion of the current-ineffective region in the area of ​​the end face of the support 30 covered by the connecting piece 70 is minimized within the allowable range. This current-ineffective region refers to the part of the connecting piece 70 where electrons tend to move along low-resistance paths, resulting in very little current flowing through its cross-section. For example... Figure 12 The portion of the area between the dashed line and the solid line that is not connected by the piece 70 can be considered a region where current is not applied. Specifically, for example... Figure 12 As shown, assuming the connecting piece 70 originally includes a plurality of electrode connecting portions 74 corresponding to the positions of the electrodes 21 of each cell 20, the electrode connecting portions 74 may be circular. In the above embodiment, the original connecting piece 70 is partially cut off in the direction where there are no other electrode connecting portions 74 to be connected.

[0154] This application also provides technical solutions related to battery pack fuses and cell voltage detection within the battery pack. A fuse 82 is installed within the battery pack 100 to provide overcurrent and other safety protections. This fuse can melt and disconnect the charging and discharging circuit of the battery pack 100 when the current exceeds its capacity. However, it generates a large amount of heat radiation during operation. Given the confined space within the battery pack 100, the heat generated by the fuse 82 may pose a safety hazard to the adjacent cell 20. In one alternative embodiment of this application, refer to… Figure 20 , Figure 21 A heat insulation device 80 is provided between the fuse and the nearby battery cell 20 within the battery pack 100. This device can block or mitigate the heat radiation and baking of the battery cell 20 by the fuse 82. In some embodiments, the heat insulation device 80 includes one or more heat insulation elements 81. The heat insulation elements 81 may be composed of a fire-resistant layer made of materials such as mica sheets and a heat insulation layer made of materials such as aerogel. It is understood that the material composition of the heat insulation elements 81 may include more options. In some embodiments, the fuse is disposed on the interface board assembly 83 of the battery pack 100 or the battery cell module 100a. The interface board assembly 83 may be fixed to the bracket 30 or the housing 10. The aforementioned heat insulation device 80 may be fixed to the bracket 30 or the interface board assembly 83 where the fuse is located on the periphery of the battery cell 20 by means of clips, bolts, screws, etc. In some embodiments, such as Figure 20 As shown, similar to the case of fuse 82, the above-mentioned heat insulation device 80 can also be provided between the main circuit wires and other electrical connectors that are electrically connected to the positive and negative terminals of the battery pack 100 or the cell module 100a and the adjacent cell 20, or the above-mentioned heat insulation component 81 can be sleeved on the main circuit wires.

[0155] To ensure the safety of the battery pack 100, parameters such as cell voltage within the pack can be monitored in real time to avoid risks such as overvoltage, overcurrent, and overtemperature. Currently, one possible implementation is to periodically obtain the voltage difference across the two ends of the cell 20 using wires. The arrangement of the wires within the pack can be designed based on the electrical connections between the cells; for example, the cell voltage can be drawn from the connecting piece 70. With increasing performance requirements for the battery pack 100, there are stricter requirements and higher expectations for the internal space arrangement. As the number of cells 20 increases, the above-mentioned wire arrangement suffers from problems such as difficulty in fixing, poor soldering, messy wiring, and large space occupation. Therefore, a battery pack cell voltage detection scheme with stable and reliable electrical parameter transmission and a more compact and neat structure is needed. (Reference) Figures 22 to 25The battery pack 100 also includes a flexible circuit board 90, which includes a substrate 92 and a conductive layer 91 such as copper wires or copper foil disposed within the insulating substrate. It has advantages such as light weight and thinness. In the embodiments of this application, an FDC (Flexible Die-cutting Circuit) board 90 can be used to collect the voltage of multiple cells 20. It can include the voltage of multiple cells 20 in the same cell module 100a, or the voltage of multiple cells 20 in different cell modules 100a. Specifically, the conductive layer 91 of the FDC board 90 can include multiple lines (copper foil) based on the electrical connection relationship between the cell module 100a and its cells 20 in the battery pack 100. Multiple electrically connected electrodes 21 have the same potential and can be connected to the same line.

[0156] In some embodiments, the FDC board 90 can be disposed on a common end face of multiple cell modules 100a and can be fixedly mounted to the bracket 30. For example, as Figure 25 As shown, assuming two battery cell modules 100a are placed vertically, the FDC board 90 can be positioned on their front side plane. Multiple battery cells 20 within the battery cell module 100a are arranged in parallel and extend vertically. Electrodes 21 are located at both axial ends of the battery cells 20, i.e., the upper and lower ends. Connecting pieces 70 can be positioned on the upper and lower side planes of the battery cell module 100a. Each connecting piece 70 can extend a portion towards the front side plane of the battery cell module 100a to provide solder joints for electrical connection with the circuitry on the FDC board 90. The FDC board 90 can be provided with multiple X-shaped positioning holes 93, and the bracket 30 can be provided with positioning posts 33 at corresponding positions. The two are interference-fitted to fix the flexible circuit board 90 to the bracket 30.

[0157] In some embodiments, the FDC board 90 may include a main circuit portion 90a and a branch circuit portion 90b. Continuing from the previous description, a line within the conductive layer 91 connected to a solder joint of a connecting piece 70 to obtain the equipotential values ​​of multiple electrodes 21 interconnected under the connecting piece 70 is considered a branch circuit. The portion of this branch circuit before it is combined with other branches, and the substrate 92 covering this portion of the branch circuit before it is combined, belongs to the branch circuit portion 90b of the FDC board 90. Alternatively, the portion of this branch circuit before it is combined with other branches not belonging to this cell module 100a, and the substrate 92 covering this portion of the branch circuit before it is combined, belongs to the branch circuit portion of the FDC board 90. Multiple branches are combined and connected to the total positive and negative terminals of the battery pack 100. This combined portion of the branches, and the substrate covering them, belongs to the main circuit portion 90a of the FDC board. This main circuit and branch circuit distribution design makes the wiring on the FDC board clearer and neater, and easily avoids wiring crossover. In some embodiments, the FDC board described above can be used not only for monitoring the battery pack voltage but also for monitoring the battery pack temperature. Similarly, the FDC board may include temperature sensors adjacent to one or more cells 20. Each temperature sensor transmits the relevant detection data to the outside of the battery pack 100 through a branch on the board. For example, an NTC (Negative Temperature Coefficient) element may also be provided near the solder joint where the connecting piece 70 extends and is connected to the branch on the FDC board.

[0158] In some embodiments, such as Figure 24 , Figure 25 As shown, to ensure a stable connection between the connecting piece 70 and the flexible circuit board 90 and the reliable transmission of relevant parameters, a mounting portion 75 protruding at an angle from the surrounding plane can be provided at the part of the connecting piece 70 that will connect with the flexible circuit board 90. For example, a buckle formed by folding the connecting piece 70 can be embedded in the through hole of the solder pad at the end of the branch of the flexible circuit board 90, thereby making it difficult for problems such as cold solder joints to occur between the two during soldering. In some embodiments, the shortest distance between the edge of the conductive layer 91 and the edge of the substrate 92, or the edge of the positioning hole 93 in the flexible circuit board 90, is greater than or equal to 2mm. That is, the substrate covering the copper foil inside the board extends at least 2mm beyond the edge of the copper foil to prevent the substrate from being easily peeled off by the copper foil and other conductive layers, causing damage, water ingress, and other problems.

[0159] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. A battery pack, characterized in that, The battery pack includes: case; A battery cell, housed within the housing, the battery cell including electrodes; A bracket, housed within the housing, supports the battery cell; A first metal plate is housed within the housing. The first metal plate is substantially perpendicular to the central axis of the battery cell and has an opening through which the gas flow ejected from the electrodes in the event of thermal runaway of the battery cell passes during thermal runaway. A second metal plate is housed within the housing. The second metal plate is substantially parallel to the first metal plate. The second metal plate and the first metal plate form an exhaust channel, which guides the airflow to exit the housing.

2. The battery pack according to claim 1, characterized in that, The first metal plate has a plurality of openings that correspond one-to-one with the electrode positions of the battery cell.

3. The battery pack according to claim 1, characterized in that, The housing has an airflow outlet, and at least a portion of the airflow outlet is provided with a fireproof component, the fireproof component being made of a different material than the housing.

4. The battery pack according to claim 3, characterized in that, The fireproof component is a metal plate with an opening located corresponding to the airflow outlet.

5. The battery pack according to claim 1, characterized in that, The first metal plate and / or the second metal plate are made of aluminum alloy.

6. The battery pack according to claim 1, characterized in that, The battery pack further includes a third metal plate and a fourth metal plate. The third metal plate is substantially perpendicular to the central axis of the battery cell and has an opening through which the airflow ejected from the electrode passes when the battery cell experiences thermal runaway. The fourth metal plate is generally parallel to the third metal plate, and the third metal plate and the fourth metal plate form an exhaust channel, which guides the airflow to exit the housing; the exhaust channel formed by the third metal plate and the fourth metal plate is located on a different side of the battery cell from the exhaust channel formed by the first metal plate and the second metal plate.

7. The battery pack according to claim 1, characterized in that, The bracket has an end face corresponding to the electrode position of the battery cell, and the end face has an opening that exposes the electrode; the battery pack further includes an end cap, which is housed in the housing and mounted to the end face of the bracket; the end cap and the end face are filled with sealant.

8. The battery pack according to claim 7, characterized in that, The first metal plate is mounted to the end cap, and the first metal plate is substantially parallel to the end cap.

9. The battery pack according to claim 8, characterized in that, The opening of the first metal plate corresponds to the opening position of the end face of the bracket.

10. The battery pack according to claim 7, characterized in that, The end cap and / or the end face are formed with an isolation element, and the sealant is divided into several areas by the isolation element, and the sealant covers the electrodes in the several areas in sections.

11. The battery pack according to claim 10, characterized in that, Multiple electrodes within the same region are electrically connected by a connecting tab, which connects the multiple electrodes within the same region via the opening of the electrode exposed on the end face.

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