Battery pack

Abstract

To provide a battery pack that can suppress misalignment of battery cells between adjacent cells while avoiding damage to the battery cells. [Solution] The battery pack 10P comprises a plurality of battery cells 10 that constitute a secondary battery ND, each having an electrode body 2, a metal battery can 1 comprising a rectangular cylindrical extruded case body 11 having an electrode body 2, a pair of short side portions 112 that house the electrode body and extend in the axial direction (Z direction), and a long side portion 111 perpendicular to the short side portions, with both axial ends 11T open, and a pair of lids 12 that seal the ends, and a restraining mechanism 5 that restrains the battery cells by applying pressure inward in the stacking direction from both ends in the stacking direction (X direction) when the battery cells are stacked with an intervening member 51 having an elastic member 51a sandwiched between the long side portions. A projection 115 is provided extending along the axial direction at the intersection 113 of the long side portion and the short side portion, which is formed to fit with both ends 511, 512 in the width direction (Y direction) perpendicular to the stacking direction of the intervening member.

Description

Technical Field

[0001] The disclosed technology relates to a battery pack that constitutes a secondary battery used as a power source for hybrid vehicles, electric vehicles, and the like.

Background Art

[0002] Generally, secondary batteries used as power sources for hybrid vehicles, electric vehicles, and the like need to flow a large current at a high voltage, so a battery pack in which a plurality of battery cells are assembled is used. In such a battery pack, for example, flat battery cells are arranged and stacked in a vertical row with an intervening member sandwiched between the battery cells, and a restraint mechanism is provided that presses and restrains the outermost battery cell inward in the stacking direction.

[0003] In this battery pack, it is necessary to electrically connect the current collecting terminals of each battery cell restrained by the restraint mechanism with a conductive plate (bus bar). However, when the battery cells are pressed inward in the stacking direction by the restraint mechanism, due to manufacturing errors such as those of the battery cells and intervening members, or uneven pressing, etc., there is a possibility that the battery cells may be displaced in the vertical direction perpendicular to the stacking direction between adjacent battery cells. And if the displacement of the battery cells is large, there is a risk of poor connection between the current collecting terminal and the conductive plate (bus bar).

[0004] As a means for suppressing the displacement of the battery cells, for example, Patent Document 1 discloses a cell holder having a support portion (protrusion) that protrudes toward the wide side surface (long side portion) of the battery cell, and a technique in which the battery cell is supported and fixed at a predetermined position while being sandwiched between the support portions (protrusions) of the cell holder and compressed with a predetermined amount of deformation.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technology described in Patent Document 1, the battery cell is supported and fixed in a state where the wide side (long side) of the battery cell is compressed by a predetermined amount of deformation by the support portion (protrusion) of the cell holder. Therefore, for example, when the internal pressure of the battery cell increases during rapid charging, the wide side (long side) of the battery cell is prone to breakage or damage at the point of deformation caused by the support portion (protrusion) of the cell holder.

[0007] This disclosed technology has been made in view of the aforementioned problems, and aims to provide a battery pack that can suppress misalignment of battery cells between adjacent battery cells while avoiding damage to the battery cells. [Means for solving the problem]

[0008] (1) One aspect of the present invention for solving the above problems is a battery pack comprising: an electrode body; a metal battery can comprising a plurality of battery cells constituting a secondary battery, each having an electrode body, a metal battery can containing the electrode body and having a pair of short side portions extending in the axial direction and a long side portion perpendicular to the short side portions, with both ends in the axial direction open; and a pair of lids that seal the ends; and a restraining mechanism that restrains the battery cells by applying pressure inward from both ends in the stacking direction while the battery cells are stacked with an intervening member having an elastic member sandwiched between the long side portions, wherein projections are provided extending along the axial direction at the intersection of the long side portions and the short side portions, and are formed to fit with both ends in the width direction perpendicular to the stacking direction of the intervening member.

[0009] (2) In the battery pack described in (1), it is preferable that the intersecting portion is recessed inward into the extruded case body between the projection and the long side portion, and that both ends of the intervening member are fitted into the recessed portion.

[0010] (3) In the battery pack described in (1) or (2), it is preferable that a locking claw is formed at the tip of the projection, which engages with both ends of the intervening member.

[0011] (4) In a battery pack described in any one of (1) to (3), it is preferable that both ends of the intervening member are formed so that the elastic member can deform and fit with the projection.

[0012] (5) In a battery pack described in any one of (1) to (4), it is preferable that the intersection portion is provided with a reinforcing portion that connects the inner surface of the long side portion and the inner surface of the short side portion. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view of a battery pack according to one aspect of this embodiment. [Figure 2] Figure 1 is a side view of the battery cells that make up the battery pack shown. [Figure 3A] This is an enlarged cross-sectional view of part A of the battery pack shown in Figure 1. [Figure 3B] Figure 3A is a perspective view of the intervening member. [Figure 4A] This is an enlarged cross-sectional view of part A in modified example 1 of the battery pack shown in Figure 1. [Figure 4B] Figure 4A is a perspective view of the intervening member. [Figure 5A] This is an enlarged cross-sectional view of part A in modified example 2 of the battery pack shown in Figure 1. [Figure 5B] Figure 5A is a perspective view of the intervening member. [Figure 6A] This is an enlarged cross-sectional view of part A in modified example 3 of the battery pack shown in Figure 1. [Figure 6B] Figure 6A is a perspective view of the intervening member. [Modes for carrying out the invention]

[0014] <Detailed description of this battery pack> Next, the overall configuration of the battery pack according to one aspect of the disclosed technology will be described in detail while referring to the drawings. FIG. 1 shows a schematic cross-sectional view of the battery pack according to one aspect of the present embodiment. FIG. 2 shows a side view of the battery cells constituting the battery pack shown in FIG. 1. FIG. 3A shows an enlarged cross-sectional view of part A of the battery pack shown in FIG. 1. FIG. 3B shows a perspective view of the intervening member shown in FIG. 3A. In FIGS. 1 to 6B, the X direction indicates the stacking direction of the battery cells in the battery pack, the Y direction indicates the width direction of the long side surface portion of the extrusion case body, and the Z direction indicates the axial direction of the extrusion case body. The X direction is also the width direction of the short side surface portion, the Y direction is also the vertical direction of the battery cells, and the Z direction is also the axial direction of the electrode body.

[0015] As shown in FIGS. 1 to 3, a battery pack 10P according to one aspect of the disclosed technology includes an electrode body 2, a square tubular extrusion case body 11 that houses the electrode body 2 and has a pair of short side surface portions 112 extending in the axial direction (Z direction) and a long side surface portion 111 orthogonal to the short side surface portions 112, and both ends 11T in the axial direction (Z direction) are open, and a pair of lid bodies 12 that seal the ends 11T, and a metal battery can 1, and a plurality of battery cells 10 that constitute a secondary battery ND. The battery cells 10 are stacked with an intervening member 51 having an elastic member 51a sandwiched between the long side surface portions 111, and a restraint mechanism 5 that pressurizes and restrains the battery cells 10 inward in the stacking direction (X direction) from both ends in the stacking direction.

[0016] Here, the electrode body 2 is an electrode body 2 formed by flatly winding a strip-shaped positive electrode foil 2a, a strip-shaped negative electrode foil 2b, and a strip-shaped separator 2c sandwiched between both electrode foils 2a and 2b, but it is not necessarily limited to this. For example, an electrode body in which a plurality of sheet-shaped positive electrode foils, sheet-shaped negative electrode foils, and sheet-shaped separators sandwiched between both electrode foils are stacked may also be used.

[0017] Also, the battery cells 10 constituting the secondary battery ND may be, for example, lithium-ion secondary batteries. In this case, the positive electrode foil 2a uses, for example, an aluminum foil, and the active material fixed thereto is, for example, a lithium transition metal oxide (LiNi 1 / 3 Co1 / 3 Mn 1 / 3 It is possible to use (such as O2, LiNiO2, etc.). The electrode foil 2b of the negative electrode uses, for example, a copper foil, and the active material fixed thereto can use, for example, graphite, hard carbon, soft carbon, etc. Further, the separator 2c can use, for example, a porous sheet such as polypropylene or polyethylene.

[0018] The metal battery can 1 is, for example, made of aluminum or an aluminum alloy, but it is not necessarily limited to this. The extrusion case body 11 is formed into a rectangular tube body having a substantially rectangular cross-section with a pair of wide long side portions 111 extending in the axial direction (Z direction) and a pair of narrow short side portions 112 (upper short side portion 112a and lower short side portion 112b). The extrusion case body 11 is a tubular body extruded in the axial direction (Z direction), and both ends 11T in the axial direction (Z direction) are open. A safety valve 119 that cracks when the pressure inside the battery can 1 rises above a predetermined value and an injection port 120 for injecting an electrolytic solution are formed in the upper short side portion 112a. The lid body 12 is formed in a flat plate shape and is connected to the end 11T of the extrusion case body 11 by welding or the like as shown in FIG. 2. A current collecting terminal 3 connected to the tab portions 2T formed at both ends in the axial direction (Z direction) of the electrode body 2 is fixed to this lid body 12 via an insulating material 4. Among the pair of lid bodies 12, a positive electrode current collecting terminal 3a is fixed to one lid body 12, and a negative electrode current collecting terminal 3b is fixed to the other lid body 12.

[0019] At the intersection 113 between the long side portion 111 and the short side portion 112, projections 115 are formed to fit with both ends 511, 512 of the intervening member 51 in the width direction (Y direction) perpendicular to the stacking direction (X direction), and these projections extend along the axial direction (Z direction). In other words, at the intersection 113 between the long side portion 111 of the extruded case body 11 and the upper short side portion 112a and lower short side portion 112b, a pair of upper and lower projections 115 protruding in the stacking direction (X direction) extend along the axial direction (Z direction). The ends 511, 512 of the intervening member 51 are sandwiched and fitted between this pair of upper and lower projections 115. Therefore, when the battery cells 10 are pressed inward in the stacking direction (X direction) by the restraining mechanism 5, each battery cell 10 is fixed to the restraining mechanism 5 with the projections 115 fitted with both ends 511, 512 of the intervening member 51 in the Y direction. Therefore, vertical displacement (Y direction) perpendicular to the stacking direction (X direction) is suppressed between the intervening member 51 and the battery cell 10, and vertical displacement (Y direction) is also suppressed between adjacent battery cells 10 with the intervening member 51 in between. Furthermore, since the projection 115 is formed at the intersection 113 of the rigid long side portion 111 and the short side portion 112, when the restraining mechanism 5 pressurizes the battery cell 10 inward in the stacking direction (X direction), the elastic member 51a absorbs the pressurizing force, and the projection 115 fits with both ends 511, 512 of the intervening member 51, so damage or breakage to the long side portion 111 and the short side portion 112 is unlikely to occur. Thus, a battery pack 10P can be made that can suppress the positional displacement of adjacent battery cells 10 while avoiding damage to the battery cells 10.

[0020] Furthermore, it is preferable that a groove 114 is provided between the projection 115 and the long side portion 111, with the intersection 113 recessed inward into the extrusion case body 11, and both ends 511, 512 of the intervening member 51 are fitted into the groove 114. In this case, each battery cell 10 can be fixed to the restraining mechanism 5 with the projection 115 more firmly fitted to both ends 511, 512 of the intervening member 51. As a result, vertical displacement (Y direction) is further suppressed even between adjacent battery cells 10 with the intervening member 51 in between. The intervening member 51 may also be provided with first fitting portions 513 formed to fit into the groove 114 at both ends 511, 512 in the vertical direction (Y direction). In this case, the amount of deformation of the elastic member 51a sandwiched between the long side portions 111 is reduced, and the pressing force P1 applied inward in the stacking direction (X direction) by the restraining mechanism 5 can be reduced.

[0021] Furthermore, a protruding ridge 116 is provided along the axial direction (Z direction) at the center of the long side portion 111 in the vertical direction (Y direction), projecting in the stacking direction (X direction). This protruding ridge 116 is formed to be able to fit with a second fitting portion 519 provided at the central portion 518 in the vertical direction (Y direction) of the intervening member 51 in the battery pack 10P. In this embodiment, the battery pack 10P is provided with an extruded case body 11 (battery cell 10) that has both a projection 115 and a protruding ridge 116, but it is not limited to this, and the battery pack 10P may also be provided with an extruded case body (battery cell) that has no protruding ridge 116 and only a projection 115.

[0022] The restraint mechanism 5 comprises a pair of side pressure plates 52 that press against the long side portion 111 of the outermost battery cell 10 with an insulating member 51b in between, a base 53 that supports the lower end portion 52U of the side pressure plates 52, and a connecting plate (not shown) that connects the left and right side pressure plates 52 (see Figure 1). It also includes a cooling unit 54 that contacts the lower short side portion 112b to cool the battery cell 10. The cooling unit 54 is fixed to the base 53, and a refrigerant flow path 541 with approximately the same width as the battery cell 10 is formed along the axial direction (Z direction) at a position facing each battery cell 10. The multiple battery cells 10 restrained by this restraint mechanism 5 are electrically connected at their respective current collection terminals 3 (the positive electrode current collection terminal 3a and negative electrode current collection terminal 3b described above) via busbars (not shown). In this embodiment, as shown in Figure 1, in addition to the lower short side portion 112b of the extrusion case body 11, a projection 115 that protrudes from the intersection 113 of the lower short side portion 112b and the long side portion 111 on the same plane as the lower short side portion 112b also contacts the cooling portion 54. Therefore, the heat generated in the battery cell 10 can be transferred to the cooling portion 54 not only from the lower short side portion 112b but also from the projection 115, allowing the battery cell 10 to be cooled more reliably.

[0023] The intervening member 51 is interposed between the battery cells 10 in the battery pack 10P, and between the battery cells 10 and the side pressure plate 52, to prevent the pressing force P1 by the restraining mechanism 5 from rising excessively when the pressure inside the battery can 1 increases. The intervening member 51 interposed between the battery cells 10 is, for example, made by bonding elastically deformable plate-shaped elastic members 51a to both sides of a sheet-shaped insulating member 51b perpendicular to the stacking direction (X direction). In contrast, the intervening member 51 interposed between the battery cells 10 and the side pressure plate 52 is made by bonding the elastic member 51a only to the surface of the insulating member 51b facing the battery cells 10. Here, the intervening member 51 is composed of two members, an elastic member 51a and an insulating member 51b, but it is not limited to this, and for example, the intervening member may be composed of one member that has insulating properties and is elastically deformable.

[0024] At both ends of the intervening member 51, located in the vertical direction (Y direction) (specifically, the upper end 511 on the upper side of the vertical direction (Y direction) and the lower end 512 on the lower side), first fitting portions 513 are provided, extending along the axial direction (Z direction) and projecting toward the battery cell 10 adjacent in the stacking direction (X direction). In the battery pack 10P, these first fitting portions 513 are inserted into the groove portions 114 of the extruded case body 11 described above, and the first fitting portions 513 at both ends 511 and 512 are fitted together with the groove portions 114. In addition, at the central portion 518 of the intervening member 51, located in the vertical direction (Y direction), a second fitting portion 519 is provided, recessed inward in the stacking direction (X direction) and extending along the axial direction (Z direction). In the battery pack 10P, the protruding portion 116 of the extruded case body 11 is inserted into the second fitting portion 519, and the second fitting portion 519 and the protruding portion 116 are fitted together.

[0025] <Variation> The embodiments described in detail above are merely illustrative and do not limit the disclosed technology in any way. Therefore, the disclosed technology can be improved and modified in various ways without departing from its gist. Figure 4A shows an enlarged cross-sectional view of part A in Modification 1 of the battery pack shown in Figure 1. Figure 4B shows a perspective view of the intervening member shown in Figure 4A. Figure 5A shows an enlarged cross-sectional view of part A in Modification 2 of the battery pack shown in Figure 1. Figure 5B shows a perspective view of the intervening member shown in Figure 5A. Figure 6A shows an enlarged cross-sectional view of part A in Modification 3 of the battery pack shown in Figure 1. Figure 6B shows a perspective view of the intervening member shown in Figure 6A.

[0026] (Battery pack of modified example 1) In the modified example 1, the battery cell 10B of the battery pack 10P has a metal battery can 1B consisting of an extruded case body 11B and a lid 12, forming a secondary battery ND. As shown in Figure 4A, at the intersection 113B of the long side portion 111 and the short side portion 112 (112a, 112b) of the extruded case body 11B, a projection 115B that protrudes in the stacking direction (X direction) extends along the axial direction (Z direction). At the tip of the projection 115B, a locking claw 115B1 is formed that extends inward (towards the intervening member 51B) in the vertical direction (Y direction). Furthermore, a recessed groove 114B is formed between the projection 115B and the long side portion 111, where the intersection 113B is recessed inward from the extruded case body 11B.

[0027] Furthermore, the intervening member 51B of the battery pack 10P in the modified example 1 is composed of an elastically deformable elastic member 51aB and an insulating member 51bB. At both ends 511 and 512 of this intervening member 51B, first fitting portions 513B, made of the elastic member 51aB, are provided extending along the axial direction (Z direction) and protruding toward the battery cell 10B adjacent in the stacking direction (X direction). The first fitting portion 513B has a tip portion 514 that protrudes toward the battery cell 10B adjacent in the stacking direction (X direction) and a groove portion 515 provided further inward in the stacking direction (X direction) than the tip portion 514. In the battery pack 10P, the tip 514 of the first fitting portion 513B is inserted into the groove portion 114B of the extruded case body 11B described above, and with the locking claw 115B1 of the projection 115 inserted into the groove portion 515 of the first fitting portion 513B, the first fitting portions 513B at both ends 511, 512 and the groove portion 114B are fitted together.

[0028] As described above, in Modification 1, a locking claw 115B1 is formed at the tip of the projection 115B, which engages with both ends 511, 512 of the intervening member 51B. Therefore, when both ends 511, 512 of the intervening member 51B engage with the locking claw 115B1 formed at the tip of the projection 115B, the projection 115B is fitted more firmly with both ends 511, 512 of the intervening member 51B, and each battery cell 10B can be fixed to the restraining mechanism 5. Consequently, vertical (Y-direction) misalignment is further suppressed between adjacent battery cells 10B with the intervening member 51B in between.

[0029] Furthermore, as shown in Figure 4A, the tip surface 115T of the projection 115B is shaped so that it does not extend beyond the outer surface 111S of the long side portion 111 when viewed in the stacking direction (X direction). Therefore, the gap between adjacent battery cells 10B in the stacking direction (X direction) can be reduced, and consequently, the decrease in energy density of the battery pack 10P can be suppressed.

[0030] (Battery pack of modified example 2) In Modification 2, the battery cell 10C of the battery pack 10P has a metal battery can 1C including an extruded case body 11C, which constitutes a secondary battery ND. As shown in Figure 5A, a projection 115C is provided along the axial direction (Z direction) from the short side portion 112 of the intersection 113C of the extruded case body 11C, projecting in the stacking direction (X direction). However, unlike the above embodiment and Modification 1, the intersection 113C is not recessed inward of the extruded case body 11C. The inner surface HN in the width direction (Y direction) of the projection 115C is formed in an inclined shape such that the tip side is thinner than the base side.

[0031] Furthermore, the intervening member 51C of the battery pack 10P in Modification 2 is composed of an elastically deformable elastic member 51aC and an insulating member 51bC. The ends 511 and 512 of the intervening member 51C are formed so that the elastic member 51aC can be compressed and deformed to fit with the projection 115C. That is, as shown in Figures 5A and 5B, in the battery pack 10P, the intervening member 51C fits with the projection 115C due to the compression deformation of the elastic member 51aC at both ends 511 and 512. Specifically, in Figure 5B, the part of the intervening member 51C before the projection 115C contacts it in the battery pack 10P (the part enclosed by the dashed line) has a corner portion 516 made of the elastic member 51aC. In other words, when the intervening member 51C is alone, it does not have a shape that can fit with the projection 115C. In a battery pack 10P in which such an intervening member 51C is interposed between battery cells 10C, the corner portion 516 of the elastic member 51aC is compressed and deformed by the pressure of the inner surface HN in the width direction (Y direction) of the projection 115C, thereby forming the first fitting portion 513C. The first fitting portions 513C at both ends 511, 512 of the intervening member 51C thus formed are fitted in the battery pack 10P while in contact with the projection 115C.

[0032] As described above, since the ends 511 and 512 of the intervening member 51C are formed so that the elastic member 51aC can be compressed and deformed to fit with the projections 115C, it is not necessary to pre-form the ends 511 and 512 of the intervening member 51C into a shape that can fit with the projections 115C. For this reason, the intervening member 51C can be a simple plate-like body, which allows for low cost and improved manufacturing accuracy. Consequently, when the battery cells 10C are pressed inward in the stacking direction (X direction) by the restraining mechanism 5, each battery cell 10C is accurately fixed to the restraining mechanism 5 with the projections 115C fitted with the ends 511 and 512 of the intervening member 51C in the vertical direction (Y direction). As a result, displacement of the battery cells 10C can be suppressed while reducing costs.

[0033] (Battery pack of modified example 3) In the modified example 3, the battery cell 10D of the battery pack 10P has a metal battery can 1D including an extruded case body 11D to constitute a secondary battery ND. As shown in Figure 6A, a projection 115D is provided along the axial direction (Z direction) from the short side portion 112 of the intersection 113D of the extruded case body 11D, projecting in the stacking direction (X direction). However, unlike the above embodiment and modified example 1, the intersection 113D is not recessed inward from the extruded case body 11D. The intersection 113D is also provided with a reinforcing portion 113D1 that connects the inner surface 111N of the long side portion 111 and the inner surface 112N of the short side portion 112 (see Figure 6A). Here, the reinforcing portion 113D1 is formed in a triangular cross-section, but is not limited to this. An inclined surface KS is formed at the tip of the projection 115D, which is inclined in the direction approaching the long side portion 111.

[0034] Furthermore, the intervening member 51D of the battery pack 10P in Modification 3 is also composed of an elastically deformable elastic member 51aD and an insulating member 51bD, similar to Modification 2. The ends 511 and 512 of the intervening member 51D are formed so that the elastic member 51aD can be compressed and deformed to fit with the projection 115D. That is, as shown in Figure 6A, in the battery pack 10P, the elastic member 51aD at both ends 511 and 512 is compressed and deformed to fit with the projection 115D. Specifically, as shown in Figure 6B, in the part of the intervening member 51D before the projection 115D comes into contact with the battery pack 10P (the part enclosed by the dashed line), there is a corner portion 516 made of the elastic member 51aD. In other words, when this intervening member 51D is alone, it does not have a shape that can fit with the projection 115D. In the case of an intervening member 51D in a battery pack 10P, for example, intervening between two battery cells 10, the corner portion 516 of the elastic member 51aD is compressed and deformed by the pressure of the inclined surface KS of the projection 115D of the adjacent battery cell 10D, thereby forming a first fitting portion 513D. The first fitting portions 513D at both ends 511 and 512 of the intervening member 51D thus formed are fitted into the battery pack 10P while in contact with the projection 115D.

[0035] As described above, the intersection 113D is equipped with the inner surface 111N of the long side portion 111 and a reinforcing portion 113D1 connecting this inner surface 111N, thereby increasing the strength of the intersection 113D between the long side portion 111 and the short side portion 112 on which the projection 115D is formed. Therefore, when the battery cells 10D are pressed inward in the stacking direction (X direction) by the restraining mechanism 5, the projection 115D can be stably fitted with both ends 511, 512 in the vertical direction (Y direction) of the intervening member 51D, and each battery cell 10D is precisely fixed by the restraining mechanism 5. As a result, displacement of the battery cells 10D can be suppressed more stably.

[0036] Furthermore, in the embodiments described above, the projections protruding to one side in the stacking direction (X direction) and the projections protruding to the other side of a single battery cell are of the same shape (see Figure 1). However, the projections protruding to one side in the stacking direction (X direction) and the projections protruding to the other side of a single battery cell may be of different shapes. Also, the projections protruding to the upper side in the vertical direction (Y direction) and the projections protruding to the lower side of a single battery cell are of the same shape (see Figure 1). However, the projections protruding to the upper side in the vertical direction (Y direction) and the projections protruding to the lower side of a single battery cell may be of different shapes. [Explanation of Symbols]

[0037] 1, 1B, 1C, 1D Battery cans 2 Electrode body 5 Restraint mechanism 10, 10B, 10C, 10D battery cells 10-pack battery 11, 11B, 11C, 11D Extrusion case body 11T end 12 Lid 51, 51B, 51C, 51D Intervening members 51a, 51aB, 51aC, 51aD Elastic members 111 Long side part 111N (Inner surface of the long side) 112 Short side part 112N (Inner surface of the short side) 113, 113B, 113C, 113D intersection 113D1 Reinforcement section 114, 114B Concave groove part 115, 115B, 115C, 115D protrusion 115B1 Locking claw 511 Upper end (both ends) 512 Lower end (both ends)

Claims

1. A plurality of battery cells comprising an electrode body, a metal battery case comprising an electrode body, a rectangular cylindrical extruded case body that houses the electrode body and has a pair of short sides extending in the axial direction and a long side perpendicular to the short sides, with both ends in the axial direction open, and a pair of lids that seal the ends, and a plurality of battery cells constituting a secondary battery, A battery pack comprising: a restraining mechanism that restrains the battery cells by applying pressure inward from both ends in the stacking direction while the battery cells are stacked with an intervening member having an elastic member sandwiched between the long side portions, At the intersection of the long side portion and the short side portion, projections are provided that are formed to fit with both ends in the width direction perpendicular to the stacking direction of the intervening member, and these projections extend along the axial direction. Battery pack.

2. In the battery pack described in claim 1, Between the projection and the long side portion, there is a groove portion in which the intersection is recessed inward from the extrusion case body. Both ends of the intervening member are fitted into the groove. Battery pack.

3. In the battery pack described in claim 2, A locking claw is formed at the tip of the projection, which engages with both ends of the intervening member. Battery pack.

4. In the battery pack described in claim 1, The ends of the intervening member are formed so that the elastic member can be compressed and deformed to fit with the projection. Battery pack.

5. In the battery pack described in claim 1, The intersection is provided with a reinforcing portion that connects the inner surface of the long side portion with the inner surface of the short side portion. Battery pack.

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