Battery device

Abstract

To provide a battery device whose frame size can be reduced.SOLUTION: A battery device 100 includes: a battery multilayer body 10 in which a plurality of battery cells 11 are stacked; a pair of end plates 20 that are disposed on both ends in a stacking direction of the battery multilayer body; and a case 30 that accommodates the battery multilayer body and the end plates. The case forms an accommodation space 34 with a bottom part 33 and annular wall parts 31 and 32 projecting with respect to the bottom part. The case has, on a short-side wall part 32 that is a part of the annular wall part and intersects with the stacking direction, a wall surface 321 that is in contact with the end plate, and a concave part 323 that is depressed with respect to the wall surface. The end plate has an end surface 26 that is in contact with the wall surface 321, and a concave part 23 that faces the concave part 323 and is depressed with respect to the end surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a battery device. [Background technology]

[0002] One example of a battery device is a battery module disclosed in Patent Document 1. The battery module includes a battery stack in which multiple battery cells are stacked, and a case to house the battery stack. A pair of end plates are provided on both ends of the battery stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-44183 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery stack is compressed and housed in the case. When the battery stack is housed in the case, a pair of pressing jigs is used to pressurize the battery stack. Each pressing jig has a leg piece that is placed in a groove of the end plate. With the leg pieces placed in the groove, the pressing jigs move toward each other to compress the battery stack.

[0005] However, the pressing tool (legs) may deform so that the lower side in the insertion direction expands when the battery stack is compressed. Accordingly, mainly the end plates are deformed so that the lower side in the insertion direction expands when pressed by the pressing tool. In addition, the case needs to be large enough to allow the battery stack to be inserted even when the end plates are deformed. Therefore, there is a risk that the battery module will become large in size.

[0006] One disclosed object is to provide a battery device that can be made compact in size. [Means for solving the problem]

[0007] The battery device disclosed herein is A battery stack (10) in which a plurality of battery cells (11) are stacked; a pair of end plates (20) arranged at both ends of the battery stack in the stacking direction; a case (30) that defines an accommodation space (34) with a bottom (33) and annular walls (31, 32) that protrude from the bottom, and that accommodates a battery stack and end plates in the accommodation space; The case has a cross side wall portion (32) which is a part of the annular wall portion and crosses the stacking direction, the cross side wall portion (32) having a case side contact surface (321) which contacts the end plate and a case side recess (323) which is recessed into the case side contact surface, The end plate has a plate-side contact surface (26) that contacts the case-side contact surface, and a plate-side recess (23) that faces the case-side recess and is recessed relative to the plate-side contact surface.

[0008] The battery device has a space surrounded by the case-side recess and the plate-side recess, into which a pressing tool can be inserted, so that the battery device can be housed in the case by compressing the battery stack and the end plates with the pressing tool.

[0009] In addition, since the battery device has a case-side recess, the space into which the pressing tool can be inserted is larger than in a configuration without a case-side recess. Therefore, even a pressing tool with a thick plate thickness can be inserted into the space surrounded by the case-side recess and the plate-side recess. In other words, a pressing tool that is suppressed in deformation during compression can be used. Therefore, when the end plate is compressed by the pressing tool, deformation that causes the lower part corresponding to the bottom of the case to expand can be suppressed.

[0010] Therefore, there is no need to take into consideration deformation of the end plates when designing the size of the case, and the size of the battery device can be reduced.

[0011] The battery device disclosed herein is A battery stack (10) in which a plurality of battery cells (11) are stacked; a pair of end plates (20a) arranged at both ends of the battery stack in the stacking direction; a case (30a) that defines an accommodation space (34a) between a bottom (33a) and annular walls (31a, 32a) that protrude from the bottom, and that accommodates a battery stack and end plates in the accommodation space; The case has a cross side wall portion (32a) that is a part of the annular wall portion and crosses the stacking direction, The end plate has a plate-side contact surface (26a) that contacts the crossing side wall portion, and a plate-side recess (23a) that faces the crossing side wall portion and is recessed with respect to the plate-side contact surface, The end plate has a lower surface (S2) facing the bottom and an upper surface (S1) opposite the lower surface, and the plate thickness along the stacking direction gradually decreases from the upper surface to the lower surface.

[0012] The battery device has a space surrounded by the intersecting side wall portions and the plate-side recesses. A pressure tool can be inserted into the space. The battery device is configured so that the battery stack and the end plates can be compressed by the pressure tool and housed in the case.

[0013] When the end plate is compressed by the pressing tool, the bottom side of the end plate is deformed in accordance with the deformation of the pressing tool so that the bottom side of the end plate expands. However, the thickness of the end plate in the stacking direction is gradually reduced from the top side to the bottom side. Therefore, even if the end plate is deformed in accordance with the deformation of the pressing tool, the bottom side of the end plate is prevented from expanding more than the top side.

[0014] Therefore, there is no need to take into consideration deformation of the end plates when designing the size of the case, and the size of the battery device can be reduced.

[0015] The aspects disclosed in this specification adopt different technical means to achieve their respective objectives. The claims and the parenthetical symbols described in this section are illustrative of the corresponding relationship with the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the following detailed description and the attached drawings. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a battery device in a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 2 is a perspective view showing a schematic configuration of a pressing jig. [Figure 6] 5A to 5C are cross-sectional views showing a method for manufacturing the battery device in the first embodiment. [Figure 7] 3A to 3C are plan views illustrating a manufacturing method of the battery device in the first embodiment. [Figure 8] FIG. 11 is a plan view showing a schematic configuration of a battery device according to a second embodiment. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 11 is a cross-sectional view showing a schematic configuration of a battery stack in a second embodiment. [Figure 11] 6A to 6C are cross-sectional views showing a method for manufacturing a battery device according to a second embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing a schematic configuration of a case in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, the other parts of the configuration may be applied by referring to the other embodiment described previously.

[0018] In the following, the three mutually perpendicular directions are referred to as the X, Y, and Z directions. Furthermore, the plane defined by the X and Y directions is referred to as the XY plane, the plane defined by the X and Z directions is referred to as the XZ plane, and the plane defined by the Y and Z directions is referred to as the YZ plane.

[0019] (First embodiment) A battery device 100 of a first embodiment will be described with reference to Figures 1 to 7. Note that the battery stack 10 is shown in a simplified form in Figures 2, 3, 6 and 7. Also, in Figure 1, the case 30 is shown in a simplified form.

[0020] <Battery device configuration> As shown in Fig. 1, the battery device 100 includes a battery stack 10, end plates 20 arranged on both ends of the battery stack 10, and a case 30 that houses the battery stack 10 and the end plates 20. A structure including the battery stack 10 and the end plates 20 can also be called a battery stack or cell stack. The battery device 100 is configured so that it can be mounted on a mobile object. The mobile object can be, for example, a vehicle such as an electric car or a hybrid car, or an aircraft.

[0021] <Battery stack> As shown in Fig. 1, the battery stack 10 has multiple battery cells 11 stacked together. The multiple battery cells 11 are stacked in the X direction. Therefore, the stacking direction of the multiple battery cells 11 coincides with the X direction. It can also be said that the multiple battery cells 11 are arranged side by side in one direction. The stacking direction can also be said to be the longitudinal direction of the battery device 100.

[0022] Each battery cell 11 is, for example, a secondary battery that can be charged and discharged. The secondary battery may be, for example, a lithium ion secondary battery. The secondary battery may also be another type of battery, such as a nickel-metal hydride secondary battery. Each battery cell 11 includes a positive electrode plate, a negative electrode plate, a separator, and a cell case that houses these. Each battery cell 11 also includes a positive electrode terminal and a negative electrode terminal, which are not shown. The cell case may be, for example, one that is mainly composed of a metal such as aluminum.

[0023] As an example, each battery cell 11 is a prismatic battery having a flat rectangular parallelepiped shape. The battery cells 11 have side surfaces along the YZ plane. The battery cells 11 are arranged so that their side surfaces face each other. In addition, in the battery stack 10, a resin frame 12 is arranged between adjacent battery cells 11. In other words, the resin frame 12 is arranged between the battery cells 11. Thus, the battery stack 10 has a configuration in which multiple battery cells 11 are stacked with the resin frames 12 interposed between them.

[0024] The resin frame 12 is disposed in the opposing region between adjacent battery cells 11. The resin frame 12 is made of an electrically insulating material. The adjacent battery cells 11 are electrically insulated by the resin frame 12 in the opposing region.

[0025] <End plate> As shown in Fig. 1, the end plates 20 are arranged at both ends of the battery stack 10 in the stacking direction. Thus, the end plates 20 are provided in pairs. It can be said that the battery device 100 is equipped with end plates 20 in two locations. Both end plates 20 have the same configuration. The end plates 20 are made of an electrically insulating material. The battery stack 10 is electrically insulated from the case 30 by the end plates 20.

[0026] The end plates 20 are disposed opposite the side surfaces of the battery cells 11 on both ends. Therefore, the resin frame 12 is disposed on one side surface of the battery cells 11 on both ends, and the end plates 20 are disposed on the other side surface.

[0027] 1, the end plate 20 includes a base portion 21 and a protrusion portion 22 protruding in the X direction from the base portion 21. It can also be said that the protrusion portion 22 protrudes from the base portion 21 toward a short wall portion 32 facing the end plate 20. In this embodiment, as an example, an end plate 20 including a plurality of protrusion portions 22 is adopted.

[0028] 2 and 3, the end plate 20 has an upper surface S1 that follows the XY plane, and a lower surface S2 that is the opposite surface to the upper surface S1 and also follows the XY plane. The protrusion 22 is provided from the upper surface S1 to the lower surface S2. The lower surface S2 is the surface that faces the housing bottom surface S12 of the case 30 when the battery stack 10 and the end plate 20 are housed in the case 30. The state in which the battery stack 10 and the end plate 20 are housed in the case 30 can also be referred to as simply the housed state.

[0029] The end plate 20 has a uniform thickness in the stacking direction from the upper surface S1 to the lower surface S2. More specifically, the thickness of the portion where the protrusion 22 is formed is uniform from the upper surface S1 to the lower surface S2. The thickness of the portion where the recess 23 is formed is uniform from the upper surface S1 to the lower surface S2. The thickness of the portion where the protrusion 22 is formed corresponds to the distance between the surface of the end plate 20 that faces the battery cell 11 and an end surface 26, which will be described later. The thickness of the portion where the recess 23 is formed corresponds to the distance between the surface of the end plate 20 that faces the battery cell 11 and a bottom surface 25, which will be described later.

[0030] The end plate 20 has an end face 26 that contacts a wall surface 321 of the case 30 in the housed state. The end face 26 is the tip surface of the protrusion 22. Thus, the end plate 20 has a plurality of end faces 26. The end faces 26 are surfaces along the YZ plane. It is sufficient that at least a portion of each end face 26 contacts the wall surface 321. The end face 26 corresponds to the plate side contact surface. The wall surface 321 corresponds to the case side contact surface.

[0031] The end plate 20 faces the recess 323 of the case 30 and has a recess 23 recessed in the X direction relative to the end face 26. The recess 23 is formed by two opposing side faces 24 and a bottom face 25 connected to both side faces 24. The side faces 24 are surfaces that extend along the XZ plane. The bottom face 25 is a surface that extends along the YX plane. The recess 23 corresponds to the plate side recess. The recess 323 corresponds to the case side recess.

[0032] The recessed portion 23 is provided adjacent to the protruding portion 22. Therefore, it can be said that the end plate 20 has a plurality of recessed portions 23. Therefore, it can be said that the end plate 20 has uneven portions when viewed in a plan view from the Z direction.

[0033] 3, the recess 23 is provided from the upper surface S1 to the lower surface S2. It can also be said that the recess 23 is open to the upper surface S1. It can also be said that the recess 23 is a groove along the Z direction.

[0034] In this embodiment, as an example, an example is adopted in which the width of each recess 23 is wider than the width of each protrusion 22. The width of the recess 23 and the protrusion 22 is the length in the Y direction. The width of each recess 23 can also be considered as the distance between adjacent protrusions 22. Similarly, the width of each protrusion 22 can also be considered as the distance between adjacent recesses 23.

[0035] As described above, in this embodiment, an end plate 20 having a plurality of recesses 23 is employed. However, the present disclosure is not limited thereto. An end plate 20 having only one recess 23 may also be employed. In this case, the end plate 20 has end faces 26 at only two locations on both sides of the recess 23. Also, an end plate 20 having only one end face 26 may also be employed. In this case, the end plate 20 has recesses 23 at only two locations on both sides of the end face 26. Both sides refer to positions adjacent to each other in the Y direction.

[0036] <Case> 1, 2, and 3, case 30 includes a bottom 33 and annular walls 31 and 32 protruding from bottom 33. Case 30 defines storage space 34 between bottom 33 and annular walls 31 and 32. Case 30 also defines an opening on the side opposite bottom 33.

[0037] The case 30 houses the battery stack 10 and the end plates 20 in a housing space 34. The case 30 is made primarily of a metal such as aluminum.

[0038] The outer shape of the case 30 has a rectangular shape when viewed from a plane in the Z direction. Therefore, the annular walls 31, 32 include two long wall portions 31 and two short wall portions 32. The two long wall portions 31 are provided in positions facing each other. The two short wall portions 32 are provided in positions facing each other. The two long wall portions 31 are provided in continuity with the two short wall portions 32. The long wall portions 31 are walls along the stacking direction. The short wall portions 32 are walls that intersect with the stacking direction and correspond to intersecting side walls. The outer shape can also be called a contour.

[0039] 2 and 3, the case 30 has an accommodation bottom surface S12 which is the surface of the bottom 33 facing the accommodation space 34, and an opening end surface S11 which is the surface of the short wall portion 32 facing the opening end of the accommodation space 34. The opening end surface S11 and the accommodation bottom surface S12 are surfaces along the XY plane.

[0040] 1, the short wall portion 32 has a plurality of protrusions 322. The protrusions 322 are portions that protrude in the X direction from a bottom surface 325, which will be described later. The protrusions 322 can also be said to protrude toward the end plate 20 that faces the short wall portion 32. The protrusions 322 can also be said to protrude toward the opposing short wall portion 32.

[0041] The short wall portion 32 has a wall surface 321 that contacts the end plate 20 in the stored state. The wall surface 321 is a tip surface of the protrusion 322. Therefore, it can be said that the short wall portion 32 has a plurality of wall surfaces 321. More specifically, the wall surface 321 contacts the end surface 26 of the end plate 20. The wall surface 321 is a surface along the YZ plane.

[0042] The short wall portion 32 has a recess 323 recessed in the X direction relative to a wall surface 321. The recess 323 is formed by two opposing side surfaces 324 and a bottom surface 325 continuous with both side surfaces 324. The side surfaces 324 are surfaces that extend along the XZ plane. The bottom surface 325 is a surface that extends along the YX plane.

[0043] The recessed portion 323 is provided adjacent to the protruding portion 322. Therefore, it can be said that the short-side wall portion 32 has a plurality of recessed portions 323. Therefore, it can be said that the short-side wall portion 32 has uneven portions in a plan view from the Z direction.

[0044] 3, the recess 323 is provided from the opening end surface S11 to the storage bottom surface S12. It can also be said that the recess 323 opens to the opening end surface S11. It can also be said that the recess 323 is a groove along the Z direction.

[0045] In the housed state, the recess 323 faces the recess 23. Therefore, in the battery device 100, a space is formed that is surrounded by the recess 323 and the recess 23. This space is the space into which the leg piece 220, which will be described later, is inserted. Therefore, the space can also be called an inserted space.

[0046] The insertion space is formed by the side surfaces 24, 324, the bottom surfaces 25, 325, and the housing bottom surface S12. Since the recess 323 is formed in the case 30, the distance between the bottom surfaces 25, 325 is wider than in a configuration in which the recess 323 is not formed (hereinafter, referred to as a comparative example). In addition, the volume of the insertion space is larger than that of the comparative example.

[0047] In the present embodiment, as an example, an example is adopted in which the width of the recess 323 is equal to the width of the recess 23. Also, the width of the protrusion 322 is equal to the width of the protrusion 22. The width of each recess 323 can be said to be the interval between adjacent protrusions 322. Similarly, the width of each protrusion 322 can be said to be the interval between adjacent recesses 323. And, the width of the recess 323 is wider than the interval between adjacent recesses 323. Therefore, the battery device 100 can increase the volume of the insertion space. The width of the recess 323 and the protrusion 322 is the length in the Y direction.

[0048] As described above, in this embodiment, the short wall portion 32 having a plurality of recesses 323 is adopted. However, the present disclosure is not limited to this. The short wall portion 32 may be adopted even if it has only one recess 323. In this case, the short wall portion 32 has wall surfaces 321 only at two locations on both sides of the recess 323. Also, the short wall portion 32 may be adopted even if it has only one wall surface 321. In this case, the short wall portion 32 has recesses 323 only at two locations on both sides of the wall surface 321.

[0049] 4, the short wall portion 32 has a chamfered portion 326 at the end opposite to the bottom portion 33. This makes it easier to insert the leg piece 220 of the pressing jig 200, which will be described later, into the battery device 100. However, the short wall portion 32 does not necessarily have to have the chamfered portion 326 formed thereon.

[0050] <Manufacturing method> Here, a manufacturing method of the battery device 100 will be described with reference to Figs. 5, 6, and 7. In this manufacturing method, a pressing tool 200 shown in Fig. 5 is used. In this manufacturing method, two pressing tools 200 are used when manufacturing one battery device 100. Therefore, it can be said that the manufacturing equipment for the battery device 100 is equipped with two pressing tools 200. The manufacturing equipment also includes a drive unit for moving the two pressing tools 200. The drive unit is capable of moving the two pressing tools 200 in both directions, approaching and receding.

[0051] The pressing jig 200 includes a base portion 210 and a plurality of leg pieces 220 protruding from the base portion 210. In this embodiment, the pressing jig 200 includes the same number of leg pieces 220 as the number of recesses 23, 323. However, the number of leg pieces 220 may be smaller than the number of recesses 23, 323.

[0052] In this embodiment, the length of the leg piece 220 in the X direction is defined as the plate thickness of the leg piece 220. The plate thickness of the leg piece 220 can be made approximately the same as the length of the inserted space in the X direction. Therefore, the plate thickness of the leg piece 220 can be made thicker than the leg piece used to house the battery stack in the case of the comparative example. The length of the leg piece 220 in the Y direction is defined as the width of the leg piece 220.

[0053] This manufacturing method mainly includes a compression step of compressing the battery stack, and an accommodation step of accommodating the compressed battery stack in a case 30. As shown in Fig. 6, in the compression step, the manufacturing device inserts the leg pieces 220 of each pressurizing jig 200 into the recesses 23 of the corresponding end plates 20. The case 300 is provided with a recess 323. The leg pieces 220 are also inserted into the recesses 323 in the accommodation step. Therefore, the leg pieces 220 may protrude from the recesses 23.

[0054] The manufacturing device moves the two pressing jigs 200 to compress the battery stack in the stacking direction. That is, the two pressing jigs 200 move toward each other with the leg pieces 220 inserted into the recesses 23. More specifically, one pressing jig 200 presses the battery stack in the X1 direction. The other pressing jig 200 presses the battery stack in the X2 direction. This causes the battery stack to be compressed from both sides in the stacking direction. At this time, the battery cases of the battery cells 11 are mainly compressed and shrunk. Therefore, the length of the battery stack is shorter than when it is housed in the case 30. The length here is the length in the X direction.

[0055] 6, the case 30 is provided with an insertion gap L0 so that the battery stack can be inserted with the leg pieces 220 inserted. The insertion gap L0 is the distance in the X direction between the end surface 26 of the battery stack in a compressed state and the wall surface 321. Therefore, the distance in the X direction between the opposing wall surfaces 321 is longer than the length in the X direction of the battery stack in a compressed state.

[0056] Then, in the accommodation step, the manufacturing equipment moves the battery stack compressed by the pressing jig 200 in the Z1 direction. That is, the manufacturing equipment moves the pressing jig 200 and the battery stack in the Z1 direction. In this way, the manufacturing equipment places the battery stack in the accommodation space 34.

[0057] 7, when the battery stack is placed in the accommodation space 34, the end face 26 faces the wall surface 321, and the recesses 23 and 323 face each other. Meanwhile, the leg piece 220 is disposed in both the recess 23 and the recess 323. In other words, the leg piece 220 is disposed in the inserted space.

[0058] The battery stack is compressed by the pressing jig 200. Therefore, the end surface 26 is in contact with the wall surface 321. Alternatively, the battery stack may be in a state where the end surface 26 is in contact with the wall surface 321 to the extent that no binding force is generated against the case 30.

[0059] The manufacturing equipment may move the case 30 in the Z2 direction. The manufacturing equipment may move the case 30 in the Z2 direction while moving the battery stack in the Z1 direction.

[0060] Thereafter, the manufacturing equipment moves the pressing jig 200 in the Z2 direction with the battery stack placed in the accommodation space 34. As a result, the leg pieces 220 are removed from the inserted space.

[0061] By removing the leg pieces 220 from the inserted space, the battery stack is released from the stress caused by the pressing jig 200. That is, the battery stack is in a state in which no stress is applied to it from the pressing jig 200 within the accommodation space 34.

[0062] Therefore, the battery stack generates a restoring force in the X12 direction. As a result, the battery stack presses the case 30 in the X direction. That is, the end face 26 presses the wall face 321 while in contact with the wall face 321. It can also be said that the battery stack generates a restraining force on the case 30 in the X12 direction. In this manner, the battery stack is housed in the case 30 to manufacture the battery device 100. The state in which the battery stack is housed in the case 30 is shown in FIG. 1.

[0063] In this manner, the battery device 100 is manufactured using the pressing jig 200. Therefore, traces caused by the pressing jig 200 remain on at least one of the end plate 20 and the case 30. On the end plate 20, for example, traces remain on parts of the two side surfaces 24 and parts of the bottom surface 25. Similarly, on the case 30, for example, traces remain on parts of the two side surfaces 324 and parts of the bottom surface 325. The traces include traces caused by the pressing jig 200 pinching the end plate 20, traces caused by inserting the leg pieces 220 into the end plate 20 or the case 30, traces caused by pulling the leg pieces 220 out of the end plate 20 or the case 30, and the like.

[0064] <Effects> In the battery device 100, a space is formed that is surrounded by the recess 323 and the recess 23. The leg pieces 220 of the pressing jig 200 can be inserted into this space. Thus, the battery device 100 is configured so that the battery stack 10 and the end plates 20 can be compressed by the pressing jig 200 and housed in the case 30.

[0065] Furthermore, since the battery device 100 has the recess 323, the space into which the leg piece 220 can be inserted is larger than in a configuration without the recess 323. Therefore, even a leg piece 220 having a thick plate thickness can be inserted into the space surrounded by the recess 323 and the recess 23. In other words, a pressing tool 200 that is suppressed from deforming during compression can be used. Therefore, when the end plate 20 is compressed by the pressing tool 200 (leg piece 220), deformation that causes the lower part corresponding to the bottom part 33 of the case 30 to widen can be suppressed.

[0066] Therefore, it is not necessary to set the size of the case 30 in consideration of deformation of the end plate 20. Therefore, the size of the battery device 100 can be reduced.

[0067] <Modification> The width of recess 323 and the width of recess 23 may be different. In other words, the width of recess 323 and the width of recess 23 may be different as long as wall surface 321 and end surface 26 can be in contact with each other. Battery device 100 can achieve the above-mentioned effects even if the width of recess 323 and the width of recess 23 are different.

[0068] Moreover, the width of recess 323 is equal to the width of recess 23. The interval between adjacent recesses 323 is equal to the interval between adjacent recesses 23. The interval between adjacent recesses 323 may be greater than the width of recess 323. That is, the width of protrusion 322 is greater than the width of recess 323. Similarly, the width of protrusion 22 is greater than the width of recess 23. This is preferable because the battery device 100 can have a greater contact area between wall surface 321 and end surface 26.

[0069] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present disclosure.

[0070] The second embodiment will be described below as another embodiment of the present disclosure. The above embodiment and the second embodiment can be implemented alone, but can also be implemented in appropriate combination. The present disclosure is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

[0071] Second embodiment A battery device 100a of the second embodiment will be described with reference to Figures 8 to 12. The battery device 100a differs from the battery device 100 in the case 30a and the end plate 20a. Note that in this embodiment, the reference numerals are followed by "a" to distinguish it from the above embodiment. Components with the same reference numerals as the above embodiment are similar to the above embodiment unless otherwise specified.

[0072] 8 and 9, the end plate 20a includes a base portion 21a, a protrusion 22a, and a recess 23a, similar to the end plate 20. The recess 23a is formed of two opposing side surfaces 24a and a bottom surface 25a connected to both side surfaces 24a. An end surface 26a is the tip surface of the protrusion 22a.

[0073] As shown in FIG. 9 and FIG. 10, the thickness of the end plate 20a in the X direction is different from that of the end plate 20. That is, the plate thickness of the end plate 20a along the stacking direction gradually becomes thinner from the upper surface S1 to the lower surface S2. More specifically, the plate thickness of the portion where the protrusion 22a is formed gradually becomes thinner from the upper surface S1 to the lower surface S2. Therefore, the end surface 26a is inclined with respect to the YZ plane. On the other hand, the plate thickness of the portion where the recess 23a is formed may be uniform from the upper surface S1 to the lower surface S2. The plate thickness of the portion where the recess 23a is formed may also gradually become thinner. The end plate 20a can be applied to the first embodiment.

[0074] 10, L1 is the thickness difference of the end plate 20a. The thickness difference L1 is the distance from the end of the lower surface S2 to the end of the upper surface S1 in the stacking direction of the end plate 20a. The thickness difference L1 can also be said to be the degree of inclination or the inclination of the end surface 26a.

[0075] 8, the case 30a has annular walls 31a, 32a and a bottom 33a, similar to the case 30. The annular walls 31a, 32a have two long walls 31a and two short walls 32a. In the case 30a, the bottom 33a and the annular walls 31a, 32a form a storage space 34a.

[0076] However, case 30a differs from case 30 in the configuration of short-side wall portion 32a. Short-side wall portion 32a does not have a recess 323. Therefore, short-side wall portion 32a has wall surface 321a over the entire surface facing end plate 20a. Wall surface 321a is a surface along the YZ plane, similar to wall surface 321. Short-side wall portion 32a corresponds to an intersecting side wall portion.

[0077] As shown in FIG. 11, the short-side wall 32a before the battery stack is accommodated is provided along the YZ plane. That is, the short-side wall 32a is perpendicular to the stacking direction. However, as shown in FIG. 9, when the battery stack is accommodated in the accommodation space 34a, the short-side wall 32a is inclined along the end plate 20a. That is, the short-side wall 32a deforms along the shape of the end plate 20a with the battery stack accommodated in the accommodation space 34a. The manufacturing method of the battery device 100a is the same as that of the first embodiment, as shown in FIG. 11.

[0078] L2 in Fig. 12 is the amount of deformation in the stacking direction of the case 30a (short side wall portion 32a). The amount of deformation L2 is the amount of displacement when a load is applied evenly from the housing space 34a side to the short side wall portion 32a. In other words, the amount of deformation L2 is the amount of displacement when a load is applied evenly to the entire area of ​​the short side wall portion 32a. It is preferable that the amount of deformation L2 is equal to or greater than the plate thickness difference L1. The amount of deformation L2 can be measured by an experiment, a simulation, or the like.

[0079] In the battery device 100a, a space is formed that is surrounded by the short wall portion 32a and the recessed portion 23a. Therefore, the battery device 100a is configured so that the battery stack can be compressed by the pressing jig 200 and accommodated in the case 30a, similar to the first embodiment.

[0080] When the end plate 20a is compressed by the pressing jig 200, the lower surface S2 side of the end plate 20a is deformed so as to expand in accordance with the deformation of the leg pieces 220 of the pressing jig 200. However, the plate thickness of the end plate 20a along the stacking direction gradually decreases from the upper surface S1 to the lower surface S2. Therefore, even if the end plate 20a is deformed in accordance with the deformation of the leg pieces 220, the lower surface S2 side of the end plate 20a can be prevented from expanding more than the upper surface S1 side.

[0081] Therefore, it is not necessary to set the size of the case 30a in consideration of deformation of the end plate 20a, and the battery device 100a can be made compact in size.

[0082] Furthermore, the battery device 100a is configured so that the deformation amount L2 is equal to or greater than the plate thickness difference L1. This allows the battery device 100a to make the load applied by the battery stack to the short-side wall portion 32a uniform. In other words, the load becomes uniform over the entire short-side wall portion 32a.

[0083] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the equivalent range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more than one element, or less than one element are also within the scope and concept of the present disclosure.

[0084] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple dependent claims. Some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. Furthermore, some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. The claims described in these multiple dependent forms define multiple technical ideas.

[0085] (Technical thought 1) A battery stack (10) in which a plurality of battery cells (11) are stacked; a pair of end plates (20) arranged at both ends of the battery stack in the stacking direction; a case (30) that defines an accommodation space (34) with a bottom (33) and annular walls (31, 32) that protrude from the bottom, and that accommodates the battery stack and the end plates in the accommodation space; The case has a cross side wall portion (32) which is a part of the annular wall portion and crosses the stacking direction, the cross side wall portion (32) having a case side contact surface (321) which contacts the end plate and a case side recess (323) which is recessed with respect to the case side contact surface, The end plate of the battery device has a plate-side contact surface (26) that contacts the case-side contact surface, and a plate-side recess (23) that faces the case-side recess and is recessed relative to the plate-side contact surface.

[0086] (Technical thought 2) the case has a plurality of the case-side recesses and a plurality of the case-side contact surfaces around each of the case-side recesses, The battery device according to Technical Idea 1, wherein the end plate has a plurality of the plate-side recesses and a plurality of the case-side contact surfaces around each of the plate-side recesses.

[0087] (Technical Thought 3) The case has a storage bottom surface (S12) which is a surface of the bottom portion facing the storage space, and an opening end surface (S11) which is a surface of the cross side wall portion facing the opening end of the storage space, The end plate has a lower surface (S2) facing the storage bottom surface and an upper surface (S1) opposite the lower surface, The case recess is open to the opening end surface side, The battery device according to Technical Idea 1 or 2, wherein the plate-side recess is open to the upper surface side.

[0088] (Technical Thought 4) The battery device according to Technical Idea 1, wherein the intersecting side wall portion has a chamfered portion (326) at the end opposite the bottom portion.

[0089] (Technical Thought 5) The battery device according to Technical Idea 1, wherein the width of the case side recess and the width of the plate side recess are different.

[0090] (Technical Thought 6) The width of the case-side recess and the width of the plate-side recess are equal, The interval between adjacent case-side recesses is equal to the interval between adjacent plate-side recesses, The battery device according to Technical Idea 2, wherein the width of the case side recess is wider than the distance between adjacent case side recesses.

[0091] (Technical Thought 7) The width of the case-side recess and the width of the plate-side recess are equal, The interval between adjacent case-side recesses is equal to the interval between adjacent plate-side recesses, The battery device according to Technical Idea 2, wherein the distance between adjacent case side recesses is greater than the width of the case side recesses.

[0092] (Technical Thought 8) The end plate has a lower surface (S2) facing the bottom and an upper surface (S1) opposite the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.Battery device described in technical idea 2.

[0093] (Technical Thought 9) A battery stack (10) in which a plurality of battery cells (11) are stacked; a pair of end plates (20a) arranged at both ends of the battery stack in the stacking direction; a case (30a) that defines an accommodation space (34a) between a bottom (33a) and annular walls (31a, 32a) that protrude from the bottom, and that accommodates the battery stack and the end plates in the accommodation space; The case has a cross side wall portion (32a) that is a part of the annular wall portion and crosses the stacking direction, the end plate has a plate-side contact surface (26a) that contacts the crossing side wall portion, and a plate-side recess (23a) that faces the crossing side wall portion and is recessed with respect to the plate-side contact surface, The end plate has a lower surface (S2) facing the bottom and an upper surface (S1) opposite the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.

[0094] (Technical Thought 10) the intersecting side wall portion deforms to conform to the shape of the end plate when the battery stack and the end plate are housed therein, A battery device described in technical idea 9, wherein the deformation amount (L2) of the intersecting side wall portion in the stacking direction is greater than or equal to the distance (L1) from the end of the lower surface to the end of the upper surface of the end plate in the stacking direction. [Explanation of symbols]

[0095] 100, 100a... battery device, 10... battery stack, 11... battery cell, 12... resin frame, 20, 20a... end plate, 21, 21a... base portion, 22, 22a... convex portion, 23, 23a... concave portion, 24, 24a... side surface, 25, 25a... bottom surface, 26, 26a... end surface, 30, 30a... case, 31, 31a... long wall portion, 32, 32a... short wall portion, 33, 33a... bottom portion, 34, 34a... accommodation space, 321, 321a... wall surface, 322... convex portion, 323... concave portion, 324... side surface, 325... bottom surface, 326... chamfered portion, 200... pressure jig, 210... base portion, 220... leg piece, S1... upper surface, S2... lower surface, S11... opening end surface, S12... accommodation bottom surface, L0... insertion gap, L1... plate thickness difference, L2... deformation amount

Claims

1. A battery stack (10) in which a plurality of battery cells (11) are stacked; A pair of end plates (20) arranged on both ends of the battery stack in the stacking direction; a case (30) that defines an accommodation space (34) with a bottom (33) and annular wall portions (31, 32) protruding from the bottom, and that accommodates the battery stack and the end plates in the accommodation space; The case has a cross side wall portion (32) which is a part of the annular wall portion and crosses the stacking direction, the cross side wall portion (32) having a case side contact surface (321) which contacts the end plate and a case side recess (323) which is recessed with respect to the case side contact surface, The end plate of the battery device has a plate-side contact surface (26) that contacts the case-side contact surface, and a plate-side recess (23) that faces the case-side recess and is recessed relative to the plate-side contact surface.

2. the case has a plurality of the case-side recesses and a plurality of the case-side contact surfaces around each of the case-side recesses, The battery device according to claim 1 , wherein the end plate has a plurality of the plate-side recesses and a plurality of the case-side contact surfaces around each of the plate-side recesses.

3. The case has a storage bottom surface (S12) which is a surface of the bottom portion facing the storage space, and an opening end surface (S11) which is a surface of the intersecting side wall portion facing the opening end of the storage space, The end plate has a lower surface (S2) facing the storage bottom surface and an upper surface (S1) opposite the lower surface, The case recess is open to the opening end surface side, The battery device according to claim 1 , wherein the plate-side recess is open to the upper surface side.

4. 2. The battery device of claim 1, wherein the intersecting side wall has a chamfer (326) at an end opposite the bottom.

5. The battery device according to claim 1 , wherein a width of the case-side recess and a width of the plate-side recess are different.

6. The width of the case-side recess and the width of the plate-side recess are equal, The interval between adjacent case-side recesses is equal to the interval between adjacent plate-side recesses, The battery device according to claim 2 , wherein a width of the case-side recess is greater than a distance between adjacent case-side recesses.

7. The width of the case-side recess and the width of the plate-side recess are equal, The interval between adjacent case-side recesses is equal to the interval between adjacent plate-side recesses, The battery device according to claim 2 , wherein the interval between adjacent case-side recesses is wider than the width of the case-side recesses.

8. The battery device described in claim 2, wherein the end plate has a lower surface (S2) facing the bottom portion and an upper surface (S1) opposite the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.

9. A battery stack (10) in which a plurality of battery cells (11) are stacked; A pair of end plates (20a) arranged at both ends of the battery stack in the stacking direction; a case (30a) that defines an accommodation space (34a) with a bottom (33a) and annular wall portions (31a, 32a) protruding from the bottom, and that accommodates the battery stack and the end plates in the accommodation space; The case has a crossing side wall portion (32a) that is a part of the annular wall portion and crosses the stacking direction, The end plate has a plate-side contact surface (26a) that contacts the crossing side wall portion, and a plate-side recess (23a) that faces the crossing side wall portion and is recessed with respect to the plate-side contact surface, The end plate has a lower surface (S2) facing the bottom and an upper surface (S1) opposite the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.

10. the intersecting side wall portion deforms to conform to the shape of the end plate when the battery stack and the end plate are housed therein, The battery device according to claim 9 , wherein a deformation amount (L2) of the intersecting side wall portion in the stacking direction is equal to or greater than a distance (L1) from an end of the lower surface to an end of the upper surface of the end plate in the stacking direction.

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