Battery pack

Abstract

To provide a battery pack that may be periodically charged with a compatible charger.SOLUTION: A battery pack includes a housing, a core box, a stack of pouch cells, an end plate, battery pack terminals, and a circuit board. The core box is disposed in the housing and has a support surface. The stack of pouch cells is supported by the support surface. Each pouch cell has cell tabs that extend from a common side of the pouch cell. The end plate has slots, and the cell tabs extend through the slots. The battery pack terminals are electrically connected to the stack of pouch cells and can be electrically connected to an electrical device. The circuit board is coupled to the core box opposite the support surface. The circuit board is electrically connected to the stack of pouch cells and the battery pack terminals. The core box, the end plate, and the circuit board cooperate to enclose the stack of pouch cells.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to co-pending U.S. Provisional Patent Application No. 63 / 342,760, filed May 17, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a battery pack, and more particularly, to a battery pack having pouch cells. [Background technology]

[0003] Typically, electrical equipment, such as cordless power tools, are powered by rechargeable batteries that can be periodically recharged with a compatible charger. Summary of the Invention [Means for solving the problem]

[0004] The present disclosure, in one aspect, provides a battery pack having a housing, a core box, a stack of pouch cells, end plates, battery pack terminals, and a circuit board. The core box is disposed within the housing and has a support surface. The stack of pouch cells is supported by the support surface. Each pouch cell has a cell tab extending from a common side of the pouch cells. The end plates have slots, and the cell tabs extend through the slots. The battery pack terminals are electrically connected to the stack of pouch cells and may be electrically connected to an electrical device. The circuit board is coupled to the core box opposite the support surface. The circuit board is electrically connected to the stack of pouch cells and the battery pack terminals. The core box, end plates, and circuit board cooperate to surround the stack of pouch cells.

[0005] In another aspect, the present disclosure provides a battery pack having a housing, a core box disposed within the housing, a stack of pouch cells disposed within the core box, end plates coupled to the core box, and a circuit board coupled to the core box. Each of the pouch cells has a cell tab coupled to a cell tab of an adjacent pouch cell. The pouch cells are electrically connected in series such that an electrical path through the pouch cells is in a serpentine pattern. The end plates have slots, and the cell tabs extend through the slots. The stack of pouch cells is at least partially surrounded by the circuit board and the core box. At least a portion of the cell tabs are disposed on a side of the circuit board opposite a side of the core box.

[0006] In yet another aspect, the present disclosure provides a battery pack having a housing, a core box disposed within the housing, a stack of pouch cells disposed within the core box, an end plate coupled to the core box, an elastic layer, a battery pack terminal, a first circuit board, a second circuit board, a voltage tap, and a thermistor. Each of the pouch cells has a cell tab coupled to a cell tab of an adjacent pouch cell. The pouch cells are electrically connected in series such that an electrical path through the pouch cells is a serpentine pattern. The end plate has a slot, and the cell tab extends through the slot. The elastic layer is disposed between adjacent pouch cells of the stack of pouch cells. The battery pack terminal is configured to electrically connect to the battery pack terminal. The first circuit board is electrically connected to the stack of pouch cells, and the second circuit board is electrically connected to the battery pack terminal. The voltage tap is electrically connected to one of the first circuit board and the second circuit board and electrically connected to the two coupled cell tabs of the adjacent pouch cells. The thermistor is electrically connected to one of the first circuit board and the second circuit board. The core box, the end plates, and the first circuit board cooperate to enclose the stack of pouch cells. [Brief description of the drawings]

[0007] [Figure 1]FIG. 2 is a front oblique view of the battery pack. [Diagram 2] FIG. 2 is a rear perspective view of the battery pack of FIG. [Diagram 3] FIG. 2 is a front view of the battery pack of FIG. [Figure 4] FIG. 2 is a rear view of the battery pack of FIG. [Diagram 5] FIG. 2 is a side view of the battery pack of FIG. [Figure 6] 2 is another side view of the battery pack of FIG. 1. [Figure 7] FIG. 2 is a top view of the battery pack of FIG. [Figure 8] FIG. 2 is a bottom view of the battery pack of FIG. [Figure 9A-9B] FIG. 2 is a perspective view of an upper housing of the battery pack of FIG. 1. [Figure 9C] FIG. 2 is a bottom view of the upper housing of the battery pack of FIG. 1. [Figure 10A-10B] 2A and 2B are perspective and bottom views of an intermediate housing of the battery pack of FIG. 1. [Figure 11] FIG. 2 is a perspective view of a lower housing of the battery pack of FIG. 1. [Figure 12] FIG. 2 is a perspective view of a grip of the battery pack of FIG. [Figure 13] FIG. 2 is a cross-sectional view of the battery pack of FIG. [Figure 14] FIG. 2 is a rear perspective view of the battery pack of FIG. 1 with the housing removed. [Figure 15] FIG. 2 is a front perspective view of the battery pack of FIG. 1 with the housing removed. [Figure 16] 2 is a perspective view of a grip cover of the battery pack of FIG. 1. [Figure 17] FIG. 2 is a perspective view of a core box of the battery pack of FIG. [Figure 18] FIG. 2 is a perspective view of a core box having an end plate of the battery pack of FIG. 1. [Figure 19] FIG. 2 is a perspective view of a core box having battery cells of the battery pack of FIG. 1. [Figure 20]FIG. 2 is a partial cross-sectional view of the battery pack of FIG. [Figure 21] FIG. 2 is a detailed cross-sectional view of the battery pack of FIG. [Figure 22] FIG. 13 is a cross-sectional view of another embodiment of a battery pack. [Figure 23A-23B] 2A and 2B are front and rear perspective views of an end plate of the battery pack of FIG. 1. [Figure 24] FIG. 2 is a partial rear perspective view of the battery pack of FIG. 1 with the housing removed. [Diagram 25] FIG. 2 is a partial rear perspective view of the battery pack of FIG. 1 with the housing removed. [Figure 26A] FIG. 2 is a top view of a circuit board of the battery pack of FIG. [Figure 26B] 2 is a side view of a circuit board of the battery pack of FIG. 1. [Figure 27] 2 is a perspective view of a terminal and a terminal housing of the battery pack of FIG. 1. [Figure 28] FIG. 2 is a perspective view of a positive terminal of the battery pack of FIG. 1. [Figure 29] FIG. 2 is another perspective view of the battery pack of FIG. 1 with the housing removed. [Diagram 30] 2 is another cross-sectional view of the battery pack of FIG. 1. [Diagram 31] FIG. 13 is a detailed view of the snap fit features of the core box circuit board. [Diagram 32] FIG. 13 is a detailed view of the snap fit features of the core box end plates. [Diagram 33] FIG. [Diagram 34] FIG. 13 is a detailed view of another swing welding operation. [Diagram 35] FIG. 13 is a perspective view of another embodiment of a battery pack with the housing removed. [Fig. 36A-36F] 2 shows an assembly process for the battery pack of FIG. 1. [Fig. 36G-36L] 2 shows an assembly process for the battery pack of FIG. 1. [Figure 37] 2 is a top view of a battery cell of the battery pack of FIG. 1. [Figure 38] 33 is a thermal graph of the battery cell of FIG. 32 when the battery is being discharged. [Figure 39] 2 illustrates airflow within the battery pack of FIG. 1 during charging. [Diagram 40] 2 illustrates airflow within the battery pack of FIG. 1 during charging. [Diagram 41] 1 illustrates airflow within different embodiments of a battery pack during charging. [Diagram 42] 1 is a graph showing the temperature of an unvented battery pack during a charging process. [Diagram 43] 1 is a graph showing the temperature of a vented battery pack during a charging process. [Diagram 44] 2 is a graph showing the temperature of the battery pack of FIG. 1 during a charging process. [Diagram 45] 1 is a table comparing the charging processes of different battery packs. [Figure 46] 1 is a graph comparing the temperatures of different battery packs during a charging process. [Figure 47] 1 is a graph comparing the runtime of different battery packs during discharge. [Figure 48] 1 is a table comparing the runtime of different battery packs during discharge. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Other features and aspects of the present invention will become apparent upon consideration of the following detailed description and accompanying drawings.

[0009] Before describing any embodiment of the present disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0010] 1-21 and 23-30, a first embodiment of a battery pack 10 is shown. The battery pack 10 is a rechargeable battery pack configured to selectively supply power to an electric device (e.g., a power tool). The battery pack 10 can be removed from the electric device and charged with a charger. The battery pack 10 includes a housing 14, a battery module 18 disposed within the housing 14, and a circuit module 22. The battery pack 10 can have an overall height of 90 mm to 70 mm. More specifically, the battery pack 10 can have an overall height of 85 mm to 75 mm. More specifically, the battery pack 10 can have an overall height of 80 mm.

[0011] The housing 14 of the battery pack 10 may include a first housing portion 26 (e.g., an upper housing portion), a second housing portion 30 (e.g., a middle housing portion), and a third housing portion 34 (e.g., a lower housing portion). The housing portions 26, 30, 34 are coupled to support the battery module 18 and the circuit module 22. The housing 14 may be formed from a first material (e.g., GF nylon) that is chemically resistant and a second material that absorbs shock if the battery pack 10 is dropped.

[0012] The housing 14 may define a first end 12 (e.g., a forward end), a second end 16 (e.g., a rearward end) opposite the first end 12, a first side 13, and a second side 15 opposite the first side 13. In the illustrated embodiment, the first end 12 and the second end 16 are shorter than the first side 13 and the second side 15.

[0013] 9A-9C, the first housing portion 26 includes a sloped region 24 and a raised region 28. The sloped region is adjacent to the first end 12 of the battery pack 10 and the raised region 28 is adjacent to the second end 16 of the battery pack. The first housing portion 26 has an overall height of d1 (FIG. 20). The overall height d1 is measured from a top surface of the sloped region 24. The overall height d1 may be between 30 mm and 20 mm. The overall height d1 may be between 28 mm and 24 mm. The overall height d1 may be between 26 mm and 25 mm. The overall height d1 may be 25.4 mm.

[0014] The first housing portion 26 may have a thickness of d5 (excluding the angled regions 24 and raised regions 28) (FIG. 20). The thickness d5 may be between 1 mm and 3 mm. The thickness d5 may be between 1.5 mm and 2.5 mm. The thickness d5 may be 2 mm.

[0015] The first housing portion 26 includes a tool interface 38 disposed on the raised region 28. The tool interface 38 is configured to physically couple to an electrical device and a charger. The tool interface 38 includes a set of terminal openings 42 that at least partially expose a set of battery pack terminals (described in more detail below). The set of terminal openings 42 allow the electrical device and charger to be electrically coupled to the battery pack 10, and more specifically, to the battery pack terminals of the battery pack 10. The tool interface 38 may further include guides 54 that allow the battery pack 10 to be easily inserted and removed from the electrical device.

[0016] The first housing portion 26 further includes a plurality of air inlets that allow air to enter the battery pack 10 and cool the battery pack 10. More specifically, the first housing portion 26 may include a first set of air inlets 46 located on the tool interface 38 and a second set of air inlets 50 (FIG. 9C) that extend along the length of the first housing portion 26. The first set of air inlets 46 includes a first group of air inlets 46a on one side of the tool interface 38 and a second group of air inlets 46b on the other side of the tool interface 38. The first set of air inlets 46 may be comprised of a plurality of circular or slot-shaped openings. The second set of air inlets 50 includes a first group of air inlets 50a that extend along the first side 13 and a second group of air inlets 50b that extend along the second side 15. The second set of air inlets 50 is comprised of a plurality of slot-shaped openings.

[0017] The first housing portion 26 may further include a plurality of holes 58 (e.g., threaded holes). The plurality of holes 58 are configured to receive fasteners 60 ( FIG. 13 ) for coupling the first housing portion 26 to the second housing portion 30. In the illustrated embodiment, the fasteners 60 are screws. In the illustrated embodiment, the plurality of holes 58 includes two holes located adjacent the first end 12 and two holes located adjacent the second end 16. In other embodiments, the first housing portion 26 may have fewer or more holes.

[0018] The first housing portion 26 may also include a set of openings 62 configured to receive the pair of gripping members (described in detail below). The openings 62 include a first opening 62a on one side of the tool interface 38 and a second opening 62b on the other side of the tool interface 38. The openings 62a, 62b may be disposed between the sloped region 24 and the raised region 28. More specifically, a portion of the openings 62a, 62b may be disposed on the sloped region 24 and a portion of the openings 62a, 62b may be disposed on the raised region 28.

[0019] The second housing portion 30 is located between the first housing portion 26 and the third housing portion 34. The second housing portion 30 forms a recess 66 that supports the battery module 18. The bottom wall of the second housing portion may have a thickness of d5. The thickness d5 may be between 1 mm and 5 mm. The thickness d5 may be between 3 mm and 4 mm. The thickness d5 may be 3.5 mm.

[0020] The second housing portion 30 includes a plurality of exhaust vents 70 that allow cooling air to exit the battery pack 10. The plurality of exhaust vents 70 includes a first set of exhaust vents 70a disposed along the first side 13 of the housing 14 and a second set of exhaust vents 70b disposed along the second side 15 of the housing 14. The plurality of exhaust vents 70 may be comprised of a plurality of slot-shaped, circular, rectangular, or elliptical openings.

[0021] The second housing portion 30 may also include access openings 72. The access openings 72 allow water to exit the battery pack 10 if water enters the battery pack 10. The access openings 72 are smaller than the exhaust openings 70. The access openings 72 may be located near the first end 12 and the second end 16 of the housing 14. In the illustrated embodiment, the battery pack 10 includes four access openings 72, although other embodiments may have fewer or more access openings.

[0022] The second housing portion 30 further includes a plurality of holes 74 (e.g., threaded holes) configured to receive the fasteners 60. The plurality of holes 74 are configured to align with the plurality of holes 58 of the first housing portion 26.

[0023] The third housing portion 34 is coupled to the second housing portion 30. The third housing portion 34 may not completely cover the second housing portion 30. The third housing portion 34 includes a plurality of holes 78 configured to receive fasteners, a plurality of exhaust ports 82, and an entry opening 80. The plurality of holes 78 align with the plurality of holes 74 of the second housing portion 30. The set of exhaust ports 82 align with the plurality of exhaust ports 70 of the second housing portion 30. The entry opening 80 aligns with the entry opening 72 of the second housing portion 30.

[0024] The housing 14 may further include a status indicator 100 and a fuel gauge button 104. The status indicator 100 may be a set of LED lights. The status indicator 100 may indicate the charge level or health of the battery pack 10. For example, the status indicator 100 may be green when the battery pack 10 is fully charged, or the status indicator 100 may be red when the battery pack 10 is at a low battery. The status indicator 100 is disposed on the sloped region 24 of the first housing portion 26.

[0025] Fuel gauge button 104 is located adjacent to status indicia 100 on sloped region 24 of first housing portion 26. Fuel gauge button 104 allows a user to check the status of battery pack 10 by pressing fuel gauge button 104. The status of battery pack 10 is displayed on status indicia 100. Fuel gauge button 104 may be used when battery pack 10 is not connected to an electrical device or charger.

[0026] The housing 14 also includes a set of grips 88. The set of grips 88 includes a first grip 88a disposed in the first opening 62a and a second grip 88b disposed in the second opening 62b. The set of grips 88 allows a user to easily hold the battery pack 10 and insert the battery pack 10 into an electrical device.

[0027] 7 and 12, the grips 88a, 88b include a compressible portion 92 and a contact plate 96. The contact plate 96 contacts the first housing portion 26 when the compressible portion 92 is compressed. The compressible portion 92 can be compressed by a user to allow the battery pack 10 to be inserted into the electric device. The compressible portion 92 is compressed in a direction perpendicular to the insertion direction of the battery pack 10. The grips 88a, 88b can further include a spring (not shown) that biases the compressible portion 92 to an uncompressed state. When the battery pack 10 is inserted into the electric device, the compressible portion 92 is not compressed, thereby securing the battery pack 10 to the electric device and preventing removal of the battery pack 10 from the electric device.

[0028] The battery pack 10 may include a grip cover 108 (FIGS. 13-16) disposed between the first housing portion 26, the battery module 18, and the circuit module 22. More specifically, the grip cover 108 is disposed between the set of grips 88 and the circuit module 22. The grip cover 108 covers the circuit module 22 and protects the circuit module 22 (and other battery pack interiors) from intrusion when the grips 88a, 88b are compressed. The grip cover 108 may include holes that allow the grip cover 108 to be secured to a portion of the circuit module 22.

[0029] 17 to 20, the battery module 18 includes a core box 112, a stack of pouch cells 114 supported by the core box 112, and end plates 116. The core box 112 is disposed in the recess 66 of the second housing portion 30.

[0030] 17 and 18, the core box 112 includes a first side wall 122, a second side wall 123 opposite the first side wall 122, and a third side wall 124. The first side wall 122 is adjacent to the first side 13, the second side wall 123 is adjacent to the second side 15, and the third side wall 124 is adjacent to the first end 12. The core box 112 also includes a support surface 125. The support surface 125 contacts the second housing portion 30. The side walls 122, 123, 124 and the support surface 125 form a recess 128 that receives the stack of pouch cells 114.

[0031] The core box 112 includes at least one opening 132 disposed on the first side wall 122 and the second side wall 123. The opening 132 may allow a sensor (e.g., a thermistor) to access the middle of the stack of pouch cells 114. The opening 132 may be slot-shaped or rectangular. In the illustrated embodiment, the core box 112 includes two slot-shaped openings 132 on each of the first side wall 122 and the second side wall 123.

[0032] The core box 112 may further include holes 136 (e.g., threaded holes) configured to receive fasteners 140 (e.g., vertical screws). The fasteners 140 couple the core box 112 to the circuit module 22. The holes 136 are disposed on the third side wall 124. The illustrated embodiment includes two holes 136, although in other embodiments, there may be fewer or more holes 136.

[0033] The core box 112 may have an overall height of 60 mm to 30 mm. More specifically, the core box 112 may have an overall height of 50 mm to 40 mm. Even more specifically, the core box 112 may have an overall height of 45.5 mm. The core box 112 has a height that is greater than 50% of the overall height of the battery pack 10. More specifically, the core box 112 has a height that is greater than 55% of the overall height of the battery pack 10. Even more specifically, the core box 112 has a height that is greater than 56% of the overall height of the battery pack 10.

[0034] The support surface 125 of the core box 112 has a thickness of d4 (FIG. 20). The thickness d4 may be between 0.5 mm and 3 mm. More specifically, the thickness d4 of the core box 112 may be between 1 mm and 2.5 mm. Even more specifically, the thickness d4 of the core box 112 may be 2 mm.

[0035] The stack of pouch cells 114 is supported by a support surface 125 of the core box 112. More specifically, the stack of pouch cells 114 is disposed on the support surface 125 of the core box 112. The stack of pouch cells 114 includes a plurality of pouch cells. More specifically, the stack of pouch cells 114 may include at least a first pouch cell 114a (e.g., an upper pouch cell) and a second pouch cell 114b (e.g., a lower pouch cell or a pouch cell furthest from the circuit board). Although the illustrated embodiment includes five pouch cells, the battery pack 10 may include fewer or more pouch cells.

[0036] Each pouch cell (e.g., first pouch cell 114a and second pouch cell 114b) in the stack of pouch cells 114 may have a thickness of d2. The thickness d2 may be between 5 mm and 8 mm. More specifically, the thickness d2 of the pouch cells may be between 6 mm and 7 mm. More specifically, the thickness d2 may be 6.8 mm.

[0037] In the illustrated embodiment, the pouch cell stack 114 has a total height of 50 mm to 20 mm. More specifically, the pouch cell stack 114 has a total height of 40 mm to 30 mm. Even more specifically, the pouch cell stack 114 has a total height of 34 mm. The pouch cell stack 114 has a height that is greater than 30% of the total height of the battery pack 10 and greater than 60% of the total height of the core box 112. More specifically, the pouch cell stack 114 has a height that is greater than 40% of the total height of the battery pack 10 and greater than 70% of the total height of the core box 112. Even more specifically, the pouch cell stack 114 has a height that is greater than 42% of the total height of the battery pack 10 and greater than 74% of the total height of the core box 112.

[0038] Each pouch cell in the stack of pouch cells 114 includes a first cell tab 142 and a second cell tab 146. The first cell tab 142 and the second cell tab 146 extend from a common side of the pouch cell (e.g., the side adjacent the second end 16 when the stack of pouch cells 114 is disposed in the battery pack 10). The first cell tab 142 may be a positive cell tab. The first cell tab 142 may be formed of copper and may have a tensile strength of 145 lbf (645 N) to 160 lbf (712 N). More specifically, the first cell tab 142 may have a tensile strength of 150 lbf (667 N) to 155 lbf (690 N). More specifically, the first cell tab 142 may have a tensile strength of 153.6 lbf (683.2 N). The second cell tab 146 may be a negative cell tab. The second cell tab 146 may be formed of aluminum and may have a tensile strength of 50 lbf (222 N) to 65 lbf (289 N) and a weld shear strength of 40 lbf (177 N) to 55 lbf (245 N). More specifically, the second cell tab 146 may have a tensile strength of 55 lbf (245 N) to 60 lbf (267 N) and a weld shear strength of 45 lbf (200 N) to 50 lbf (222 N). More specifically, the second cell tab 146 may have a tensile strength of 57.9 lbf (257 N) and a weld shear strength of 48.19 lbf (214.4 N). The cell tabs 142, 146 may be flexible so as to be foldable.

[0039] The first pouch cell 114a is the top battery cell, and therefore the first pouch cell 114a is located adjacent to the circuit module 22. The second pouch cell 114b is stacked between the first pouch cell 114a and the support surface 125 of the core box 112. The second pouch cell 114b is the bottom battery cell, and therefore the second pouch cell 114b is adjacent to the support surface 125. In the illustrated embodiment, the stack of pouch cells 114 further includes a third pouch cell 114c located directly below the first pouch cell 114a, a fourth pouch cell 114d located directly below the third pouch cell 114c, and a fifth pouch cell 114e disposed directly below the fourth pouch cell 114d and above the second battery cell 114b.

[0040] 19, the pouch cells in the stack of pouch cells 114 are arranged in an alternating pattern. For example, the first cell tab 142a of the first pouch cell 114a, the first cell tab 142d of the fourth pouch cell 114d, and the first cell tab 142b of the second pouch cell 114b are adjacent to the second side 15, while the first cell tab 142c of the third pouch cell 114c and the first cell tab 142e of the fifth pouch cell 114e are adjacent to the first side 13 of the battery pack 10. Additionally, the second cell tab 146a of the first pouch cell 114a, the second cell tab 146d of the fourth pouch cell 114d, and the second cell tab 146b of the second pouch cell 114b are adjacent the first side 13, while the second tab 146c of the third pouch cell 114c and the second cell tab 146e of the fifth pouch cell 114e are adjacent the second side 15 of the battery pack 10. The alternating pattern allows the stack of pouch cells 114 to be electrically connected in a serpentine pattern (described in more detail below).

[0041] The end plate 116 is coupled to the core box 112. More specifically, the end plate 116 is coupled to the core box 112 opposite the third side wall 124 such that the end plate 116 is adjacent the second end 16. In the illustrated embodiment, the end plate 116 is snap-fitted (e.g., with a detent mechanism) to the core box 112 as shown in FIG. 32. More specifically, the core box 112 includes a protrusion 290 and a slot 306 adjacent the protrusion, and the end plate 116 includes a groove 302 and a protrusion 310. The slot 306 is a vertical slot and extends vertically between the first housing portion 26 and the second housing portion 30. The groove 302 is a horizontal groove and extends axially between the first end 12 and the second end 16. The protrusion 310 is a hook or cantilever. When the end plate 116 is coupled to the core box 112, the projection 290 of the core box 112 is received in the groove 302 of the end plate 116 and the projection 310 of the end plate 116 is received in the slot 306 of the core box 112. The snap fits limit axial movement of the end plate 116 relative to the core box 112. In the illustrated embodiment, there are two snap fits coupling the end plate 116 to the core box 112, although in other embodiments there may be more snap fits. The end plate 116 and core box 112 at least partially surround the stack 114 of pouch cells.

[0042] The end plate 116 includes a first surface 158, a second surface 162, and a set of slots 138 extending from the first surface 158 to the second surface 162. The first surface 158 is adjacent the second end 16 of the battery pack 10 and the second surface 162 is adjacent the stack of pouch cells 114. The set of slots 138 align with the cell tabs 142, 146 of the pouch cells in the stack of pouch cells 114 such that the cell tabs 142, 146 extend through the slots 138.

[0043] The first surface 158 includes a set of slots 138, a set of recesses 174, and a set of shelves 166 located adjacent holes 178. The set of shelves 166 extend toward the second end 16. The set of shelves 166 prevent the terminal tabs from contacting each other and shorting out. The set of recesses 174 are a set of recessed surfaces that may receive sensors (e.g., voltage taps) that measure the discharge condition of each battery cell. The holes 178 (e.g., screw holes) allow the end plate 116 to be coupled to the circuit module 22 when fasteners (e.g., screws) are received in the holes 178.

[0044] The second surface 162 includes a contact surface 170. The contact surface 170 extends toward the stack of pouch cells 114. The contact surface 170 contacts the stack of pouch cells 114 to stabilize the stack of pouch cells 114.

[0045] The cell tabs 142, 146 of the pouch cells 114a-114e are electrically connected to each other outside the end plate 116. In another manner as described above, the cell tabs 142, 146 of the pouch cells 114a-114e are electrically connected to each other between the end plate 116 and the second end 16 of the battery pack 10. The cell tabs 142, 146 are electrically connected to each other by folding the cell tabs 142, 146 against the end plate 116 on top of each other.

[0046] The stack of pouch cells 114 are connected in series such that the electrical path through the stack of pouch cells 114 is in a serpentine pattern. More specifically, the first cell tab 142b of the second pouch cell 114b (located on the second side 15) is connected to the second cell tab 146e of the fifth pouch cell 114e (located on the second side 15), the first cell tab 142e of the fifth pouch cell 114e (located on the first side 13) is connected to the second cell tab 146e of the fourth battery cell 114d (located on the first side 13), the first cell tab 142d of the fourth battery cell 114d (located on the second side 15) is connected to the second cell tab 146c of the third battery cell 114c (located on the second side 15), and the first cell tab 142c of the third battery cell 114c (located on the first side 13) is electrically connected to the second cell tab 146a of the first battery cell 114a. Welds 262 (FIG. 36E) may secure the cell tabs 142, 146 to one another. These connections form an electrical pathway having a serpentine pattern. The stack of pouch cells 114 is electrically connected such that a first cell tab 142a of a first pouch cell 114a is electrically connected to a second cell tab 146b of a second pouch cell 114b.

[0047] The first cell tab 142a of the first pouch cell 114a serves as a first main tab 182, and the second cell tab 146b of the second pouch cell 114b serves as a second main tab 186. The first main tab 182 and the second main tab 186 electrically connect the stack of pouch cells 114 to the circuit module 22.

[0048] The battery module 18 may further include an elastic layer 150 disposed between at least some of the cells in the stack of pouch cells 114. The elastic layer 150 may be a compressible foam expansion pad, an air gap, or a compressible bi-material spacer. The elastic layer 150 allows the pouch cells 114a-114e to expand. In the illustrated embodiment, the battery module 18 includes the elastic layer 150 between all of the adjacent pouch cells (e.g., the first pouch cell 114a and the third pouch cell 114c) in the stack of pouch cells 114. In some of the embodiments, the elastic layer 150 may be present between only some of the cells in the stack of pouch cells 114. For example, the elastic layer 150 may be present only between the first pouch cell 114a and the third pouch cell 114c and between the fifth pouch cell 114e and the second pouch cell 114b.

[0049] The elastic layer 150 has a thickness d3. The thickness d3 of the elastic layer 150 may be 1 mm to 3 mm. More specifically, the thickness d3 of the elastic layer 150 may be 1 mm to 2 mm. Even more specifically, the thickness d3 of the elastic layer 150 may be 1.5 mm. In the illustrated embodiment, the stack 114 of pouch cells including the elastic layer 150 has a height that is greater than 40% of the total height of the battery pack 10 and greater than 75% of the total height of the core box 112. More specifically, the stack 114 of pouch cells including the elastic layer 150 has a height that is greater than 45% of the total height of the battery pack 10 and greater than 80% of the total height of the core box 112. Even more specifically, the stack 114 of pouch cells including the elastic layer 150 has a height that is greater than 50% of the total height of the battery pack 10 and greater than 87% of the total height of the core box 112.

[0050] In some embodiments, the battery pack 10 may have an elastic layer disposed between the second pouch cell 114b and the support surface 125. In other embodiments, the battery pack 10 may have an elastic layer between the stack of pouch cells 114 and the first side wall 122 and / or the second side wall 123 of the core box 112.

[0051] 22 shows another embodiment of the battery pack 10'. The battery pack 10' is similar to the battery pack 10, but the battery pack 10' is more compact. The battery pack 10' does not include an elastic layer between any of the cells.

[0052] The battery module 18 may further include an upper elastic layer 154. The upper elastic layer 154 is disposed between the first pouch cell 114a and the circuit module 22. The upper elastic layer 154 may be of the same material and thickness as the elastic layer 150, or the upper elastic layer 154 may have a different thickness and may be of a different material than the elastic layer 150.

[0053] 25 to 30, the circuit module 22 includes a battery pack terminal 192, a first circuit board 194 (e.g., a lower circuit board), and a second circuit board 198 (e.g., an upper circuit board) disposed on top of the first circuit board 194.

[0054] The battery pack terminals 192 include a first battery pack terminal 226, a second battery pack terminal 230, and a third battery pack terminal 234. The first battery pack terminal 226 is a positive battery terminal. The second battery pack terminal 230 is a negative battery pack terminal. The first battery pack terminal 226 and the second battery pack terminal 230 are configured to supply a connected electrical device. The third battery pack terminal 234 is configured to transmit signals and information to the connected electrical device. The battery pack terminals 192 extend through the terminal opening 42 of the first housing portion 26. In the illustrated embodiment, the battery pack 10 includes three of the third battery pack terminals 234.

[0055] 27 and 28, the first battery pack terminal 226 and the second battery pack terminal 230 include a battery connection portion 238 and a tool connection portion 242. The battery connection portion 238 extends downwardly toward the first circuit board 194 such that the first battery pack terminal 226 and the second battery pack terminal 230 may be electrically coupled to the stack of pouch cells 114. The tool connection portions 242 of the battery pack terminals 226, 230 extend in a direction toward a plane that is coplanar with the end plate 116. The first battery pack terminal 226 and the second battery pack terminal 230 may be formed of EFTEC97 or EFTEC550-E.

[0056] The first circuit board 194 is located on the core box 112. The first circuit board 194 and the core box 112 at least partially surround the stack of pouch cells 114. More specifically, the first circuit board 194 is located on the upper elastic layer 154 and opposite the support surface 125 of the core box 112. The first circuit board 194 covers the core box 112 such that the core box 112, the first circuit board 194, and the end plate 116 cooperate to form an enclosed space and cooperate to surround the stack of pouch cells 114. The first circuit board 194 includes holes 206 (e.g., screw holes) that align with the holes 136 of the core box 112 and the holes 178 of the end plate 116 such that the fasteners 140 can secure the first circuit board 194 to the core box 112 and the end plate 116.

[0057] 31, the first circuit board 194 is secured (e.g., snap-fit) to the core box 112 by at least one snap 286 (e.g., a detent mechanism). In the illustrated embodiment, the core box 112 includes four snaps 286, including two snaps 286 along the first side wall 122 and two snaps 286 on the second side wall 123 of the core box 112. The snaps 286 include hook-shaped or cantilever-shaped protrusions 298. The hook-shaped protrusions 298 extend partially along the first circuit board 194 and limit the vertical movement of the first circuit board 194. The hook-shaped protrusions 298 may be vertically offset from the first circuit board 194 so that the stack of pouch cells 114 has room to expand. In other embodiments, the core box 112 may include fewer or more snaps 286.

[0058] The first circuit board 194 has a flat planar shape. The first circuit board 194 may be an aluminum-backed circuit board having a circuit copper layer, a dielectric layer, and an aluminum layer. The first circuit board 194 may have a thickness of d8. In the illustrated embodiment, the thickness d8 of the first circuit board 194 may be 1 mm to 3 mm. More specifically, the thickness d8 of the first circuit board 194 may be 1.5 mm to 2.5 mm. Even more specifically, the thickness d8 of the first circuit board 194 may be 2 mm.

[0059] The first circuit board 194 includes power routing elements that electrically connect the stack of pouch cells 114 to the battery pack terminals 192. More specifically, the power routing elements electrically connect the first primary cell tab 182 to the first battery pack terminal 226 and the second primary cell tab 186 to the second battery pack terminal 230.

[0060] The first primary cell tab 182 is folded over the first circuit board 194 such that at least a portion of the first primary cell tab 182 is disposed on a side of the first circuit board 194 facing the core box 112. The first primary cell tab 182 is coupled to a first battery pack terminal 226 by a terminal bus bar 210 (e.g., a first bus bar). The terminal bus bar 210 rests directly on the top surface of the first primary cell tab 182 such that the terminal bus bar 210 is directly coupled to the first primary cell tab 182. The first primary cell tab 182 is welded to the terminal bus bar 210 with a weld 266 (FIG. 36I). The weld 266 may be similar to the weld 262 (described in more detail below) and may have a rocker shape.

[0061] Terminal busbar 210 may be one integral piece, or terminal busbar 210 may be formed from multiple sections that are electronically connected. For example, terminal busbar 210 includes a first terminal busbar piece 210a connected to first primary cell tab 182 and a second terminal busbar piece 210b connected to first terminal busbar piece 210a and first battery pack terminal 226. First terminal busbar piece 210a may be formed from copper or a copper alloy such as FAS-680. First terminal busbar piece 210a may have a thickness of 0.1 mm to 0.4 mm and may have a weld shear strength of 145 lbf (645 N) to 160 lbf (712 N). More specifically, first terminal busbar piece 210a may have a thickness between 0.2 mm and 0.3 mm and may have a weld shear strength between 150 lbf (667 N) and 155 lbf (690 N). More specifically, first terminal busbar piece 210a may have a thickness of 0.25 mm and a weld shear strength of 153.6 lbf (683.2 N). Second terminal busbar piece 210b may be formed from copper or a copper alloy such as C1100. Second terminal busbar piece 210b may have a thickness between 1 mm and 1.5 mm. More specifically, second terminal busbar piece 210b may have a thickness between 0.25 mm and 0.75 mm. More specifically, second terminal busbar piece 210b may have a thickness of 0.5 mm. First terminal busbar piece 210a is welded to second terminal busbar piece 210b at weld 266.

[0062] The first and second terminal busbar pieces 210a and 210b may be electrically connected to connection pads 210c disposed on the first circuit board 194. The connection pads 210c may be formed of copper or a copper alloy, such as C110. The connection pads 210c may have a thickness between 0.2 mm and 1.75 mm. More specifically, the connection pads 210c may have a thickness between 0.5 mm and 1.5 mm. More specifically, the connection pads 210c may have a thickness of 0.58 mm. The connection pads 210c electrically connect the first primary cell tab 182 to the first circuit board 194. The welds 266 may extend through the first terminal busbar piece 210a, the second terminal busbar piece 210b, and the connection pads 210c. When thinner terminal busbar pieces are used, a lower power laser may be used to weld the terminal busbar pieces.

[0063] The second primary cell tab 186 is adjacent the support surface 125 of the core box 112. The second primary cell tab 186 is connected to a second battery pack terminal 230 by a terminal bus bar 214 (e.g., a second bus bar). The terminal bus bar 214 includes a first terminal bus bar piece 214a and a second terminal bus bar piece 214b. The first terminal bus bar piece 214a connects the second primary cell tab 186 to the first circuit board 194. The first terminal bus bar piece 214a extends along the end plate 116 and folds over an edge of the first circuit board 194. A first end of the first terminal bus bar piece 214a is welded to the second primary cell tab 186 and a second end of the first terminal bus bar piece 214a is folded over and welded to the first circuit board 194. Welding the first terminal busbar piece 214a directly to the first circuit board 194 helps absorb heat. A separator 246 (e.g., an insulating frame) may be located between the first terminal busbar piece 214a and the cell tabs 142, 146 to prevent short circuits. The separator 246 may be formed of an insulating material. The second terminal busbar piece 214b is connected to the first circuit board 194 and the second terminal 230. Unlike the terminal busbar 210, the first terminal busbar piece 214a and the second terminal busbar piece 214b are not welded, but instead, the first terminal busbar piece 214a and the second terminal busbar piece 214b are physically separated and only electrically connected through the first circuit board 194. The second terminal busbar piece 214b may be electrically connected to a connection pad 214c. Second terminal busbar segment 214b may be welded to connection pad 214c with weld 266.

[0064] The first circuit board 194 includes DFETs (discharge field effect transistors) 218. The DFETs 218 are electrically connected to the power path elements to control the power path. For example, the DFETs 218 may disconnect the power path circuit to prevent overcurrent. In the illustrated embodiment, the first circuit board 194 includes four DFETs 218, but other embodiments may use fewer or more DFETs 218. The DFETs 218 are used to protect the battery pack 10 from overcurrent and overheating. The DFETs 218 are mounted directly on the first circuit board 194 so that the DFETs help absorb heat.

[0065] The first circuit board 194 is electrically connected to the second circuit board 198. A plurality of aluminum standoffs 202 couple the first circuit board 194 to the second circuit board 198. Each standoff in the plurality of aluminum standoffs has a brake torque of 1.1 Nm, a pull strength of 330 N, and a shear force of 154 N at a distance of 6 mm.

[0066] The second circuit board 198 is located on the first circuit board 194. The second circuit board 198 can control the information of the battery pack 10 and discharge current.

[0067] The second circuit board 198 includes a terminal housing 222 that supports the battery pack terminals 192. The terminal housing 222 includes separators 224 that separate and prevent the battery pack terminals 192 from contacting each other. The terminal housing 222 may be formed of an insulating material or plastic. The terminal housing 222 has a section that extends downward toward and may contact the first circuit board 194.

[0068] The second circuit board 198 may further include a secondary terminal support 236. The secondary terminal support 236 may be formed of metal and may be located around the terminal housing 222. The secondary terminal support 236 further supports the battery pack terminals 192 when the battery pack 10 is dropped. The secondary terminal support 236 may have a thickness of d6. The thickness d6 may be between 1 mm and 3 mm. The thickness d6 may be between 1.5 mm and 2.5 mm. The thickness d6 may be 2.25 mm.

[0069] An air gap exists between the secondary terminal support 236 and the first circuit board 194. The air gap may have a thickness of d7. The thickness d7 may be between 1 mm and 2 mm. The thickness d7 may be between 1 mm and 1.5 mm. The thickness d7 may be 1.35 mm.

[0070] The circuit module 22 further includes at least one thermistor 250 and a voltage tap 258. The thermistor 250 monitors the temperature of the pouch cells 114a-114e in the stack of pouch cells 114. The thermistor 250 may be a flex circuit. In the illustrated embodiment, the battery pack includes a first thermistor 250a adjacent the first side 13 and a second thermistor 250b adjacent the second side 15. The thermistors 250a, 250b have a first end 251 that connects to the first circuit board 194 and a second end 252 that extends between the pouch cells 114a-114e in the stack of pouch cells 114. The first end 251 of the thermistors 250a, 250b extends partially between the first side 13 and the second side 15 along the first circuit board 194. More specifically, a first end 251a of the first thermistor 250a extends from the second side 15 along the first circuit board toward the first side 13, and a first end 251b of the second thermistor 250b extends from the first side 13 along the first circuit board 194 toward the second side 15.

[0071] A second end 252 of the thermistors 250a, 250b extends down outside the core box 112. The second end 252 of the thermistors 250a, 250b access the stack of pouch cells 114 by extending through an opening 132 disposed on the side walls 122, 123 of the core box 112 to enter a recess 128 of the core box 112. The second end 252 includes branches 253 extending between the pouch cells 114a-114e. More specifically, the first thermistor 250a includes a first branch 253a extending partially between the first pouch cell 114a and the third pouch cell 114c, while the second thermistor 250b includes a first branch 253b extending partially between the third pouch cell 114c and the fourth pouch cell 114d. The first thermistor 250a may further include a second branch 253c extending partially between the fourth pouch cell 114d and the fifth pouch cell 114e, and the second thermistor may further include a second branch 253d extending partially between the second pouch cell 114b and the fifth pouch cell 114e. The second end 252 may contact the pouch cell 114a-114e at the warmest portion of the pouch cell 114a-114e. Similar to the first end 251, the second end 252 of the thermistor 250a, 250b also extends between the second side 15 and the first side 13.

[0072] The voltage tap 258 monitors the discharge voltage of the stack of pouch cells 114. The voltage tap 258 includes a flex circuit 256 and a voltage sensor 254. The flex circuit 256 is electrically connected to the first circuit board 194 and the end plate 116. The flex circuit 256 extends partially along the first circuit board 194 from the second end 16 to the first end 12. The flex circuit 256 also extends along the end plate 116.

[0073] The voltage sensor 254 is disposed within the recess 174 in the end plate 116 such that the voltage sensor 254 is located between the cell tabs 142 , 146 and the end plate 116 . More specifically, there is a first voltage sensor 254a connected to the first cell tab 142b of the second pouch cell 114b and the second cell tab 146e of the fifth pouch cell 114e, a second voltage sensor 254b connected to the first cell tab 142d of the fourth pouch cell 114d and the second cell tab 146c of the third pouch cell 114c, a third voltage sensor 254c connected to the first cell tab 142e of the fifth pouch cell 114e and the second cell tab 146d of the fourth pouch cell 114d, and a fourth voltage sensor 254d connected to the first cell tab 142c of the third pouch cell 114c and the second cell tab 146a of the first pouch cell 114a. The voltage sensors 254a-254d are welded to the cell tabs 142, 146 with welds 262 such that the voltage sensors 254a-254d measure the voltage at each weld 262. The voltage sensors 254a-254d are coupled to a flex circuit 256. The voltage sensors 254a-254d may be snapped onto the flex circuit 256.

[0074] 33, the weld 262 has an oscillating pattern. The weld 262 includes a first peak 263 (e.g., a positive or highest peak) and a second peak 264 (e.g., a negative or lowest peak). The peaks 263, 264 of the weld 262 are rounded. In the illustrated embodiment, the peaks 263, 264 have different widths. More specifically, the first peak 263 is wider than the second peak 264. In other embodiments, the second peak 264 may be wider than the first peak 263, or the peaks 263, 264 may have the same width. The weld 262 has a flat shape such that a portion of the amplitude of the weld has a straight or flat line. In some embodiments, the straight portion of the weld is one-fifth of the amplitude. In some embodiments, the straight portion of the weld is one-quarter of the amplitude. In some embodiments, the straight portion of the weld is one-third of the amplitude.

[0075] Another weld 262' is shown in FIG. 34. The weld 262' also has an oscillating pattern and includes a first peak 263' and a second peak 264'. The peaks 263', 264' have a pointed shape. The first peak 264' can have a width similar to the thickness of the first peak 263 or the second peak 264 of the weld 262. The second peak 264' is narrower than the first peak 263' and narrower than the second peak 264 of the weld 262. The second peak 264' is narrow enough that the section of the weld 262' near the portion of the second peak 264' is double welded. During welding, the weld pattern of the weld 262' requires the laser to start and stop at the peaks 263', 264' of the weld 262' and the laser to fold back when welding the peaks 263', 264'.

[0076] Circuit module 22 may include a controller (not shown) that controls operation of battery pack 10 based on information from thermistor 250 and voltage tap 258. For example, the controller may prevent battery pack 10 from discharging if the measured temperature exceeds a certain temperature threshold. The controller may also prevent battery pack 10 from discharging if the measured voltage falls below a certain voltage threshold.

[0077] In the illustrated embodiment, the battery pack 10 is an 18 volt battery pack. In the illustrated embodiment, the voltage at the first voltage sensor 254a is 3.6 volts, the voltage at the third voltage sensor 254c is 7.2 volts, the voltage at the second voltage sensor 254b is 10.8 volts, and the voltage at the fourth sensor 254d is 14.4 volts. The voltage at the first primary cell tab 182 is 18 volts. The voltage at the second primary cell tab 186 is 0 volts. The voltage values ​​may vary depending on the cells used in the battery pack 10 and the number of cells used in the battery pack 10.

[0078] FIG. 35 shows another embodiment of a battery pack 1010. The battery pack 1010 is similar to the battery pack 10, and only the differences will be described in detail. The battery pack 1010 includes a core box 1112 including a stack of pouch cells, a first circuit board 1194, a second circuit board 1198 disposed on the top surface of the first circuit board 1194, a thermistor 1250, and a voltage tap 1258. The core box 1112 includes only one opening 1132 on one of the side walls and adjacent to the thermistor 1250. Unlike the battery pack 10, the battery pack 1010 includes only one thermistor 1250, which is located between the stack of cells and the core box 1112. In addition, the voltage tap 1258 of the battery pack 1010 is electrically coupled to the second circuit board 1198 and not coupled to the first circuit board 1194.

[0079] 36A-36L show a method of assembling the battery pack 10. The stack of pouch cells 114 is stacked on the outside of the core box 112. The stack of pouch cells 114 may include an elastic layer 150 between some or all of the pouch cells 114a-114e. The pouch cells 114a-114e are stacked in an alternating pattern. A thermistor 250 is placed between the cells in the stack of pouch cells 114, and the stack of pouch cells 114 with the thermistor 250 is placed on the support surface 125 of the core box 112 (FIG. 36B). Next, the end plate 116 is secured to the core box 112 (FIG. 36C). The end plate 116 may be snap-fitted to the core box 112. The voltage sensor 254 is secured to the end plate 116 and the cell tabs 142, 146 are folded onto the outside of the end plate 116. In some embodiments, the stack of pouch cells 114 is stacked onto the inside of the core box 112. In some embodiments, the cell tabs 142, 146 are folded onto the inside of the core box 112 after the first circuit board 194 is coupled to the core box 112.

[0080] The first circuit board 194 is then coupled to the core box 112 and the end plates 116 such that the first circuit board 194, core box 112, and end plates 116 surround the stack of pouch cells 114 (FIG. 36D). The first circuit board 194 is coupled to the core box 112 and the end plates 116 using fasteners 140 and snaps 286. The cell tabs 142, 146 are then welded such that there are welds 262 connecting adjacent cell tabs 142, 146 (FIG. 36E). A terminal bus bar 210 is then connected to the first primary cell tab 182 and terminal bus bar 214, and a separator 246 is connected to the second primary cell tab 186 (FIG. 36F).

[0081] The next step is fixing the second circuit board 198 to the first circuit board 194 (FIG. 36G). Then, the voltage tap 258 and thermistor 250 are placed so as to be connected to the stack of pouch cells 114 and the first circuit board 194 (FIG. 36H). Next, the electrical elements are welded using welds 266 (FIG. 36I). The welds 266 ensure that the stack of pouch cells 114 is electrically coupled to the first battery pack terminal 226 and the second battery pack terminal 230. In some embodiments, the second circuit board 198 is pre-assembled with the first circuit board 194 so that the second circuit board 198 is placed with the first circuit board 194. In some embodiments, the electrical elements are welded using welds 266 before the voltage tap 258 and thermistor 250 are placed or connected to the first circuit board 194.

[0082] The battery module 18 and circuit module 22 are then sprayed or coated with a thin film to protect the elements from intrusion (FIG. 36J). The thin film may be a polymer such as perylene. The battery module 18 and circuit module 22 may be inserted into the second housing portion 30 (FIG. 36K). The first housing portion 26 may be coupled to the second housing portion 30 with fasteners 60 (FIG. 36L). The fasteners 60 may be inserted from the second housing portion 30 such that the fasteners extend from the second housing portion 30 to the first housing portion 26.

[0083] 37 and 38, the temperature of one of the pouch cells 114a-114e during discharge is shown. The temperature of the pouch cell was taken at a first location 270, a second location 274, and a third location 278. The first location is on a side of the second cell tab 146, the second location 274 is on a side of the first cell tab 142, and the third location 278 faces the cell tabs 142, 146 and is between the first location 270 and the second location 274.

[0084] 38, when the cell is discharged at 50 amps, the cell reaches a maximum temperature of 49 degrees Celsius. When the cell is being discharged at 50 amps, the cell does not reach a temperature higher than 50 degrees Celsius. The maximum temperature occurs at a third location 278. When the cell is placed in the battery pack 10, a thermistor 250 is placed on the cell at the third location 278, whereby the thermistor 250 measures the maximum temperature of the cell. The cell reaches the maximum temperature after 300 seconds of discharge.

[0085] 39 and 40 show a cooling air flow path 282 of the battery pack 10. The cooling air flow path extends between the first set 46 and second set 50 of air inlets disposed on the first housing portion 26 and the set 70 of air outlets disposed on the second housing portion 30. The cooling air flow path 282 passes between the housing 14 and the core box 112. A flow of air (e.g., air from a charger) flows along the cooling air flow path 282 to cool the battery pack 10 to prevent the battery pack 10 from overheating.

[0086] FIG. 41 shows a cooling air flow path 282'' of a conventional battery pack 10''. Unlike the cooling air flow path 282 that passes between the housing 14 and the core box 112, the cooling air flow path 282'' extends from the first housing portion 26'' to the second housing portion 30'' into the core box of the battery pack 10''. As shown in FIG. 37, the conventional battery pack 10'' has a high temperature on the side of the battery pack 10'' (e.g., between the housing and the core box).

[0087] 42-46 compare four different battery packs during charging. The first battery pack may include battery pack vents (e.g., inlet and outlet vents) but does not include airflow. The second battery pack may include airflow but does not include any pack vents. The third battery pack is battery pack 10, which includes pouch cells, cooling air flow paths 282, and pack vents (e.g., inlets 46, 50 and outlet 70). The fourth battery pack includes cylindrical cells, air flow paths, and pack vents.

[0088] Referring to FIG. 42, the first battery pack starts charging at time t1, takes time t2 to become fully charged, and takes time t3 to fully cool down to 30 degrees Celsius. The time t1 it takes for the first battery pack to start charging is 12 minutes. The time t2 it takes for the first battery pack to fully charge is 35 minutes. The time t3 it takes for the first battery pack to fully charge is 97 minutes. The first battery pack has a total charge cycle time (e.g., the sum of t1, t2, and t3) of 145 minutes. The first battery pack receives a charge current of 13.5 amps and experiences current throttling during the charge cycle.

[0089] Referring to FIG. 43, the second battery pack starts charging at time t1', takes time t2' to fully charge, and takes time t3' to fully cool down to 30 degrees Celsius. The time t1' it takes the second battery pack to start charging is 6 minutes. The time t2' it takes the second battery pack to fully charge is 28 minutes. The time t3' it takes the second battery pack to fully charge is 80 minutes. The second battery pack has a total charge cycle time (e.g., the sum of t1', t2', and t3') of 114 minutes. The second battery pack receives a charge current of 18 amps and experiences current throttling during the charge cycle.

[0090] Referring to FIG. 44, battery pack 10 (i.e., the third battery pack) starts charging at time t1'', ​​takes time t2'' to be fully charged, and takes time t3'' to be fully cooled down to 30 degrees Celsius. The time t1'' it takes battery pack 10 to start charging is 2 minutes. The time t2'' it takes battery pack 10 to fully charge is 23 minutes. The time t3'' it takes battery pack 10 to fully charge is 53 minutes. Battery pack 10 has a total charge cycle time (e.g., the sum of t1'', ​​t2'', and t3'') of less than 80 minutes. More specifically, battery pack 10 has a total charge cycle time of 78 minutes. Battery pack 10 has a shorter charge cycle than the charge cycles of the first and second battery packs. Battery pack 10 receives a charge current of 18 amps and, unlike the first and second battery packs, does not experience current throttling during the charge cycle.

[0091] Referring to FIG. 45, the fourth battery pack takes 1 minute to start charging and 44 minutes to fully charge. After charging, the battery pack takes 41 minutes to cool down to 37 degrees Celsius. The total charging cycle for the fourth battery pack is completed within 86 minutes. The fourth battery pack is charged with a current of 12 amps and experiences no current throttling during the charging cycle. Although the fourth battery pack starts charging before battery pack 10, the battery pack takes longer to charge, and therefore the total charging cycle time is longer for the fourth battery pack compared to battery pack 10.

[0092] 47 and 48 compare four different battery cells during discharge. The first battery cell is a 6.0 Ah MP battery cell. The second battery cell is a 12.0 Ah MP battery cell. The third battery cell is a vented 8 Ah battery cell. The fourth battery cell is a 6 Ah pouch cell. The stack of pouch cells 114 may be constructed from the fourth type of battery cell.

[0093] The first battery cell may have a discharge current of 20 amps to 60 amps. When the first battery cell is discharged at any current between 20 amps and 60 amps, it may fully discharge without overheating, but at 60 amps the first battery cell is undervoltage. When the first battery cell is discharged at 20 amps, the first battery cell has a runtime of 17.7 minutes. When the first battery cell is discharged at 60 amps, the first battery cell has a runtime of 5.8 minutes.

[0094] The second battery cell may have a discharge current of 20 amps to 100 amps. When the second battery cell is discharged at any current between 20 amps to 50 amps, it may fully discharge without overheating, but at currents greater than 50 amps, the second battery cell will overheat. When the second battery cell is discharged at 20 amps, the second battery cell has a runtime of 23.4 minutes. When the second battery cell is discharged at 50 amps, the second battery cell has a runtime of 9.6 minutes. When the second battery cell is discharged at 100 amps, it has a runtime of 2.7 minutes before overheating.

[0095] The third battery cell may have a discharge current of 20 amps to 100 amps. When the third battery cell is discharged at any current between 20 amps to 60 amps, it may fully discharge without overheating, but at currents greater than 60 amps, the third battery cell will overheat. When the third battery cell is discharged at 20 amps, the fourth battery cell has a runtime of 35.8 minutes. When the third battery cell is discharged at 60 amps, the third battery cell has a runtime of 9.2 minutes. When the third battery cell is discharged at 100 amps, it has a runtime of 3.6 minutes before overheating.

[0096] The fourth battery cell may have a discharge current of 20 amps to 100 amps. When the fourth battery cell is discharged at any current between 20 amps to 60 amps, it may discharge completely without overheating, but at currents greater than 60 amps, the fourth battery cell will overheat. When the fourth battery cell is discharged at 20 amps, the fourth battery cell has a runtime of 16.7 minutes. When the fourth battery cell is discharged at 60 amps, the fourth battery cell has a runtime of 5.8 minutes. When the fourth battery cell is discharged at 100 amps, it has a runtime of 2.7 minutes before overheating.

[0097] Various features of the invention are set forth in the following claims. [Explanation of symbols]

[0098] 10 Battery pack 14 Housing 18 Battery Module 22 Circuit Module 26 First housing part 30 Second housing part 34 Third housing part 46 First set of air intakes 50 Second set of air intakes 70 Exhaust port 82 Exhaust port 112 Core Box 114 Pouch cell stack 114a first pouch cell 114b Second pouch cell 114c Third pouch cell 114d 4th pouch cell 114e 5th pouch cell 116 End Plate 125 Support surface 142 First Cell Tab 146 Second Cell Tab 150 Elastic layer 192 Battery pack terminal 194 First Circuit Board 198 Second Circuit Board 210 Terminal Busbar 226 1st battery pack terminal 230 Second Battery Pack Terminal 234 3rd Battery Pack Terminal 246 Separator 250 Thermistor 258 Voltage Tap

Claims

1. 1. A battery pack comprising: Housing and a core box disposed within the housing, the core box including a support surface; and a stack of pouch cells supported by the support surface, each pouch cell having a cell tab extending from a common side of the pouch cells; an end plate coupled to the core box, the end plate having a slot defined therein, the cell tabs extending through the slot; a battery pack terminal electrically connected to the stack of pouch cells, the battery pack terminal configured to electrically connect to an electric device; and a circuit board coupled to the core box facing the support surface, the circuit board being electrically connected to the stack of pouch cells and the battery pack terminals; Equipped with The battery pack, wherein the core box, the end plates, and the circuit board cooperate to enclose the stack of pouch cells.

2. 10. The battery pack of claim 1, further comprising an elastic layer disposed between adjacent pouch cells of the stack of pouch cells.

3. 10. The battery pack of claim 1, further comprising an elastic layer disposed between the circuit board and the stack of pouch cells.

4. 2. The battery pack of claim 1, wherein the stack of pouch cells has a height that is greater than 60% of a height of the core box.

5. 5. The battery pack of claim 4, wherein the stack of pouch cells has a height that is greater than 70% of the height of the core box.

6. 10. The battery pack of claim 1, wherein the battery pack has a height of between 85 mm and 75 mm.

7. The battery pack of claim 1 , wherein the core box has a height that is greater than 50% of a total height of the battery pack.

8. The battery pack of claim 7 , wherein the core box has a height that is greater than 55% of the overall height of the battery pack.

9. 10. The battery pack of claim 1, wherein the stack of pouch cells has a height that is greater than 30% of a total height of the battery pack.

10. 10. The battery pack of claim 9, wherein the stack of pouch cells has a height that is greater than 40% of the overall height of the battery pack.

11. The battery pack of claim 1 , wherein the battery pack terminals extend in a direction toward a plane that is coplanar with the end plate.

12. The battery pack of claim 1 , wherein the cell tabs are folded against the end plates.

13. the housing includes an air inlet and an air outlet; a cooling air flow path extending from the air inlet to the air outlet; The battery pack of claim 1 , wherein the cooling air flow path extends between the core box and the housing.

14. The battery pack of claim 1 , wherein the core box is snap-fitted to the end plates.

15. The battery pack of claim 1 , wherein the core box is snap-fit ​​to the circuit board.

16. 1. A battery pack comprising: Housing and a core box disposed within the housing; a stack of pouch cells disposed within the core box, each of the pouch cells including a cell tab that is coupled to a cell tab of an adjacent pouch cell, the pouch cells being electrically connected in series such that an electrical path through the pouch cells is in a serpentine pattern; an end plate coupled to the core box, the end plate having a slot defined therein, the cell tabs extending through the slot; an elastic layer disposed between adjacent pouch cells of the stack of pouch cells; a battery pack terminal electrically connected to the stack of pouch cells, the battery pack terminal configured to electrically connect to an electric device; and a first circuit board electrically connected to the stack of pouch cells; a second circuit board electrically connected to the battery pack terminal; a voltage tap electrically connected to at least one of the first circuit board and the second circuit board and two associated cell tabs of adjacent pouch cells; a thermistor electrically connected to one of the first circuit board and the second circuit board; Equipped with The battery pack, wherein the core box, the end plates, and the first circuit board cooperate to enclose the stack of pouch cells.

Images