Battery device

Abstract

A battery device (100) comprises: a battery stack (10) in which a plurality of battery cells (11) are stacked; end plates (20) that form a pair disposed at both ends of the battery stack in the stacking direction; and a case (30) that houses the battery stack and the end plates. The case forms a housing space (34) with a bottom section (33) and annular wall sections (31, 32) protruding from the bottom section. The case also has, in a short wall section (32) that is a part of the annular wall sections and intersects the stacking direction, a wall surface (321) in contact with the end plates, and a recess (323) recessed with respect to the wall surface. The end plates have an end surface (26) in contact with the wall surface (321), and a recess (23) facing the recess (323) and recessed with respect to the end surface.

Description

battery device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-173007 filed in Japan on October 4, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to a battery device.

[0003] 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 is provided on both ends of the battery stack.

[0004] Japanese Patent Application Laid-Open No. 2021-44183

[0005] The battery stack is compressed and housed in the case. When the battery stack is housed in the case, a pair of pressure jigs is used to pressurize the battery stack. Each pressure jig has legs that are placed in grooves in the end plates. With their legs placed in the grooves, the pressure jigs move toward each other to compress the battery stack.

[0006] However, when compressing the battery stack, the pressing jig (leg pieces) may deform downward in the insertion direction. Accordingly, the end plates, in particular, deform downward in the insertion direction when pressed by the pressing jig. Furthermore, the case must be large enough to allow the battery stack to be inserted even with the end plates deformed. This can result in the battery module becoming larger.

[0007] One disclosed object is to provide a battery device that can be made smaller in size.

[0008] The battery device disclosed herein comprises: a battery stack in which a plurality of battery cells are stacked; paired end plates arranged at both ends of the battery stack in the stacking direction; and a case that forms a storage space with a bottom and an annular wall that protrudes from the bottom, and that houses the battery stack and the end plates in the storage space; the case has, on an intersecting side wall that is part of the annular wall and intersects the stacking direction, a case-side contact surface that contacts the end plates and a case-side recess that is recessed into the case-side contact surface; and the end plates have a plate-side contact surface that contacts the case-side contact surface and a plate-side recess that faces the case-side recess and is recessed into the plate-side contact surface.

[0009] The battery device has a space surrounded by the case recess and the plate recess, and a pressure jig can be inserted into this space. The battery device is configured so that the battery stack and end plates can be compressed by the pressure jig and housed in the case.

[0010] Furthermore, because the battery device has a case-side recess, the space into which a pressure tool can be inserted is larger than in a configuration without a case-side recess. Therefore, even a thick pressure tool can be inserted into the space surrounded by the case-side recess and the plate-side recess. In other words, a pressure tool that suppresses deformation during compression can be used. Therefore, when the end plate is compressed by the pressure tool, deformation that expands downward corresponding to the bottom of the case can be suppressed.

[0011] Therefore, there is no need to consider deformation of the end plates when determining the size of the case, and the size of the battery device can be reduced.

[0012] The battery device disclosed herein comprises: a battery stack in which a plurality of battery cells are stacked; paired end plates arranged at both ends of the battery stack in the stacking direction; and a case that forms a storage space with a bottom and an annular wall that protrudes from the bottom, and that houses the battery stack and the end plates in the storage space; the case has a crossing side wall that is part of the annular wall and crosses the stacking direction; the end plates have a plate-side contact surface that contacts the crossing side wall and a plate-side recess that faces the crossing side wall and is recessed into the plate-side contact surface; the end plates have a lower surface that faces the bottom and an upper surface that is the opposite surface to the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.

[0013] The battery device has a space surrounded by the cross side wall portion and the plate-side recessed portion, and a pressure jig can be inserted into this space. Therefore, the battery device is configured so that the battery stack and end plates can be compressed by the pressure jig and housed in the case.

[0014] When compressed by the pressure jig, the end plate deforms so that the bottom side expands in response to the deformation of the pressure jig. However, the thickness of the end plate along the stacking direction gradually decreases from the top to the bottom. Therefore, even if the end plate deforms in response to the deformation of the pressure jig, the bottom side can be prevented from expanding more than the top side.

[0015] Therefore, there is no need to consider deformation of the end plates when determining the size of the case, and the size of the battery device can be reduced.

[0016] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0017] 8 is a plan view showing a schematic configuration of a battery device in a first embodiment. FIG. 1 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 1 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 1 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 1 is a perspective view showing a schematic configuration of a pressing jig. FIG. 8 is a cross-sectional view showing a method for manufacturing a battery device in a first embodiment. FIG. 9 is a plan view showing a schematic configuration of a battery device in a second embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 9 is a cross-sectional view showing a schematic configuration of a battery stack in a second embodiment. FIG. 9 is a cross-sectional view showing a method for manufacturing a battery device in a second embodiment. FIG. 10 is a cross-sectional view showing a schematic configuration of a case in a second embodiment.

[0018] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be assigned the same reference numerals, and duplicated explanations 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.

[0019] In the following description, the three mutually orthogonal directions are referred to as the X, Y, and Z directions. 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.

[0020] First Embodiment A battery device 100 according to a first embodiment will be described using Figures 1 to 7. Note that Figures 2, 3, 6, and 7 show simplified illustrations of the battery stack 10. Also, Figure 1 shows a simplified illustration of the case 30.

[0021] <Configuration of Battery Device> As shown in Figure 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. The 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 hybrid car, or an aircraft.

[0022] <Battery Stack> As shown in Fig. 1 , the battery stack 10 is made up of multiple stacked battery cells 11. 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.

[0023] Each battery cell 11 is, for example, a rechargeable secondary battery. The secondary battery may be, for example, a lithium-ion secondary battery. Alternatively, the secondary battery may be another type, 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 (not shown). The cell case may be made primarily of a metal, such as aluminum.

[0024] 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. Therefore, the battery stack 10 has a configuration in which multiple battery cells 11 are stacked with the resin frame 12 interposed between them.

[0025] The resin frame 12 is disposed in the opposing region of 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.

[0026] <End Plates> As shown in Figure 1 , the end plates 20 are arranged at both ends of the battery stack 10 in the stacking direction. Therefore, 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.

[0027] The end plates 20 are arranged opposite the side surfaces of the battery cells 11 on both ends. Therefore, the resin frame 12 is arranged on one side surface of the battery cells 11 on both ends, and the end plates 20 are arranged on the other side surface.

[0028] 1 , the end plate 20 includes a base portion 21 and protrusions 22 that protrude in the X direction relative to the base portion 21. The protrusions 22 can also be said to protrude relative to the base portion 21 toward the short-side wall portion 32 that faces the end plate 20. In this embodiment, as an example, an end plate 20 that includes a plurality of protrusions 22 is used.

[0029] 2 and 3 , the end plate 20 has an upper surface S1 that is aligned with the XY plane and a lower surface S2 that is the opposite surface of the upper surface S1 and also aligned with the XY plane. The protrusion 22 extends from the upper surface S1 to the lower surface S2. The lower surface S2 faces the housing bottom surface S12 of the case 30 when the battery stack 10 and end plate 20 are housed in the case 30. The state in which the battery stack 10 and end plate 20 are housed in the case 30 can also be referred to simply as the housed state.

[0030] The end plate 20 has a uniform thickness along 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 facing 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 facing the battery cell 11 and a bottom surface 25, which will be described later.

[0031] The end plate 20 has an end surface 26 that contacts the wall surface 321 of the case 30 in the accommodated state. The end surface 26 is the tip surface of the convex portion 22. Therefore, the end plate 20 has a plurality of end surfaces 26. The end surfaces 26 are surfaces that lie along the YZ plane. It is sufficient that at least a portion of each end surface 26 contacts the wall surface 321. The end surface 26 corresponds to the plate-side contact surface. The wall surface 321 corresponds to the case-side contact surface.

[0032] 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 a plate-side recess. The recess 323 corresponds to a case-side recess.

[0033] The recessed portions 23 are provided adjacent to the protruding portions 22. Therefore, it can be said that the end plate 20 has a plurality of recessed portions 23. Therefore, it can also be said that the end plate 20 has uneven portions when viewed in a plan view from the Z direction.

[0034] 3, the recess 23 is provided from the upper surface S1 to the lower surface S2. The recess 23 can also be said to be open to the upper surface S1. The recess 23 can also be said to be a groove extending along the Z direction.

[0035] 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 widths of the recess 23 and the protrusion 22 are lengths 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.

[0036] As described above, this embodiment employs an end plate 20 having a plurality of recesses 23. However, the present disclosure is not limited to this. 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, one on each side of the recess 23. Furthermore, 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, one on each side of the end face 26. "Both sides" refers to positions adjacent to each other in the Y direction.

[0037] 1, 2, and 3, the case 30 includes a bottom 33 and annular wall portions 31 and 32 protruding from the bottom 33. The case 30 has an accommodation space 34 formed by the bottom 33 and the annular wall portions 31 and 32. The case 30 also has an opening formed on the side opposite the bottom 33.

[0038] 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.

[0039] The outer shape of the case 30 is rectangular (rectangular) when viewed from above in the Z direction. Therefore, the annular wall portions 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 continuous with the two short wall portions 32. The long wall portions 31 are walls that extend 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 referred to as a contour.

[0040] 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 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.

[0041] 1, the short-side 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. It can also be said that the protrusions 322 protrude toward the end plate 20 that faces the short-side wall portion 32. It can also be said that the protrusions 322 protrude toward the opposing short-side wall portion 32.

[0042] The short wall portion 32 has a wall surface 321 that contacts the end plate 20 in the accommodated state. The wall surface 321 is the 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 that extends along the YZ plane.

[0043] The short wall portion 32 has a recess 323 recessed in the X direction relative to the wall surface 321. The recess 323 is formed by two opposing side surfaces 324 and a bottom surface 325 connected to 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.

[0044] The recessed portions 323 are provided adjacent to the protruding portions 322. Therefore, it can be said that the short wall portions 32 have a plurality of recessed portions 323. Therefore, it can be said that the short wall portions 32 have uneven portions when viewed in a plan view from the Z direction.

[0045] 3, the recess 323 is provided from the opening end surface S11 to the storage bottom surface S12. The recess 323 can also be said to be open to the opening end surface S11. The recess 323 can also be said to be a groove extending along the Z direction.

[0046] 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 insertion space.

[0047] The insertion space is formed by the side surfaces 24, 324, the bottom surfaces 25, 325, and the housing bottom surface S12. Because the recess 323 is formed in the case 30, the distance between the bottom surfaces 25, 325 is wider than in a configuration without the recess 323 (hereinafter referred to as the comparative example). The volume of the insertion space is also larger than in the comparative example.

[0048] In this 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. Furthermore, the width of the protrusion 322 is equal to the width of the protrusion 22. The width of each recess 323 can also be considered the distance between adjacent protrusions 322. Similarly, the width of each protrusion 322 can also be considered the distance between adjacent recesses 323. The width of the recess 323 is wider than the distance between adjacent recesses 323. Therefore, the battery device 100 can increase the volume of the insertion space. Note that the widths of the recess 323 and the protrusion 322 are lengths in the Y direction.

[0049] As described above, this embodiment employs a short-side wall portion 32 having a plurality of recesses 323. However, the present disclosure is not limited to this. The short-side wall portion 32 may also be one having only one recess 323. In this case, the short-side wall portion 32 has wall surfaces 321 at only two locations, one on each side of the recess 323. The short-side wall portion 32 may also be one having only one wall surface 321. In this case, the short-side wall portion 32 has recesses 323 at only two locations, one on each side of the wall surface 321.

[0050] 4, the short wall portion 32 has a chamfered portion 326 at the end opposite the bottom portion 33. This makes it easier to insert the leg pieces 220 of the pressing jig 200 (described later) into the battery device 100. However, the short wall portion 32 does not necessarily have to have the chamfered portion 326.

[0051] <Manufacturing Method> Here, a manufacturing method for the battery device 100 will be described using Figures 5, 6, and 7. In this manufacturing method, a pressure tool 200 shown in Figure 5 is used. In this manufacturing method, two pressure tools 200 are used to manufacture one battery device 100. Therefore, it can be said that the manufacturing apparatus for the battery device 100 is equipped with two pressure tools 200. The manufacturing apparatus also includes a drive unit that moves the two pressure tools 200. The drive unit can move the two pressure tools 200 in directions toward and away from each other.

[0052] 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.

[0053] 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 set to be approximately the same as the length of the insertion 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.

[0054] 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 apparatus inserts the leg pieces 220 of each pressing jig 200 into the recesses 23 of the corresponding end plates 20. Note that the case 300 is provided with recesses 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.

[0055] The manufacturing equipment moves the two pressure jigs 200 to compress the battery stack in the stacking direction. That is, the two pressure jigs 200 move toward each other with the leg pieces 220 inserted into the recesses 23. More specifically, one pressure jig 200 presses the battery stack in the X1 direction. The other pressure jig 200 presses the battery stack in the X2 direction. This compresses the battery stack 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 refers to the length in the X direction.

[0056] As shown in Fig. 6, the case 30 has an insertion gap L0 so that a 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.

[0057] 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.

[0058] 7 , when the battery stack is placed in the accommodation space 34, the end surface 26 faces the wall surface 321, and the recesses 23 and 323 face each other. Meanwhile, the leg pieces 220 are arranged in both the recesses 23 and 323. In other words, the leg pieces 220 are arranged in the insertion space.

[0059] 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.

[0060] The manufacturing apparatus may move the case 30 in the Z2 direction. Alternatively, the manufacturing apparatus may move the case 30 in the Z2 direction while moving the battery stack in the Z1 direction.

[0061] Thereafter, the manufacturing device 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 insertion space.

[0062] When the leg pieces 220 are removed from the inserted space, the battery stack is released from the stress caused by the pressing jig 200. In other words, the battery stack is no longer subjected to stress from the pressing jig 200 within the accommodation space 34.

[0063] 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. In other words, the end surface 26 presses the wall surface 321 while in contact with the wall surface 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 .

[0064] In this manner, the battery device 100 is manufactured using the pressing jig 200. As a result, traces from the pressing jig 200 remain on at least one of the end plate 20 and the case 30. For example, traces remain on parts of the two side surfaces 24 and part of the bottom surface 25 of the end plate 20. Similarly, traces remain on parts of the two side surfaces 324 and part of the bottom surface 325 of the case 30. Examples of traces include traces caused by the pressing jig 200 clamping the end plate 20, traces caused by inserting the leg pieces 220 into the end plate 20 or the case 30, and traces caused by pulling the leg pieces 220 out of the end plate 20 or the case 30.

[0065] <Effects> A space is formed in the battery device 100 surrounded by the recess 323 and the recess 23. The leg pieces 220 of the pressing jig 200 can be inserted into this space. Therefore, 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.

[0066] Furthermore, because 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 thick leg piece 220 can be inserted into the space surrounded by the recess 323 and the recess 23. In other words, a pressing jig 200 that is suppressed from deforming during compression can be used. Therefore, when the end plate 20 is compressed by the pressing jig 200 (leg piece 220), deformation that widens downwards corresponding to the bottom 33 of the case 30 can be suppressed.

[0067] Therefore, it is not necessary to design 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.

[0068] <Modifications> The width of the recess 323 may be different from the width of the recess 23. In other words, the width of the recess 323 may be different from the width of the recess 23 as long as it is possible for the wall surface 321 to contact the end surface 26. The battery device 100 can achieve the above-described effects even if the width of the recess 323 is different from the width of the recess 23.

[0069] Furthermore, the width of the recess 323 is equal to the width of the recess 23. The distance between adjacent recesses 323 is equal to the distance between adjacent recesses 23. The distance between adjacent recesses 323 may be wider than the width of the recess 323. In other words, the width of the protrusion 322 is wider than the width of the recess 323. Similarly, the width of the protrusion 22 is wider than the width of the recess 23. This is preferable because the battery device 100 can increase the contact area between the wall surface 321 and the end surface 26.

[0070] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and various modifications are possible without departing from the spirit and scope of the present disclosure.

[0071] A second embodiment will be described below as another aspect of the present disclosure. The above embodiment and the second embodiment can be implemented independently, or can 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.

[0072] Second Embodiment A battery device 100a according to a second embodiment will be described using Figures 8 to 12. The battery device 100a differs from the battery device 100 in the case 30a and end plates 20a. Note that in this embodiment, the letter "a" is added to the reference numerals to distinguish it from the above embodiment. Components with the same reference numerals as the above embodiment are the same as the above embodiment unless otherwise specified.

[0073] 8 and 9, the end plate 20a has 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.

[0074] As shown in Figures 9 and 10, the thickness of the end plate 20a in the X direction is different from that of the end plate 20. That is, the thickness of the end plate 20a along the stacking direction gradually decreases from the upper surface S1 to the lower surface S2. More specifically, the thickness of the portion where the convex portion 22a is formed gradually decreases 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 thickness of the portion where the concave portion 23a is formed may be uniform from the upper surface S1 to the lower surface S2. Note that the thickness of the portion where the concave portion 23a is formed may also gradually decrease. The end plate 20a can also be applied to the first embodiment.

[0075] 10, L1 denotes 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 referred to as the degree of inclination or the inclination of the end surface 26a.

[0076] 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 longitudinal walls 31a and two lateral walls 32a. The case 30a has an accommodation space 34a formed by the bottom 33a and the annular walls 31a, 32a.

[0077] However, the case 30a differs from the case 30 in the configuration of the short wall portion 32a. The short wall portion 32a does not have a recess 323. Therefore, the entire surface of the short wall portion 32a facing the end plate 20a is the wall surface 321a. Note that, like the wall surface 321, the wall surface 321a is a surface along the YZ plane. The short wall portion 32a corresponds to an intersecting side wall portion.

[0078] As shown in FIG. 11 , the short-side wall 32 a is provided along the YZ plane before the battery stack is accommodated. That is, the short-side wall 32 a is perpendicular to the stacking direction. However, as shown in FIG. 9 , when the battery stack is accommodated in the accommodation space 34 a, the short-side wall 32 a is inclined along the end plate 20 a. That is, the short-side wall 32 a deforms along the shape of the end plate 20 a with the battery stack accommodated in the accommodation space 34 a. Note that the manufacturing method of the battery device 100 a is the same as that of the first embodiment, as shown in FIG. 11 .

[0079] L2 in Figure 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 to the short-side wall portion 32a from the housing space 34a side. 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 be equal to or greater than the difference in plate thickness L1. The amount of deformation L2 can be measured by experiment, simulation, or the like.

[0080] The battery device 100a has a space surrounded by the short wall portion 32a and the recess 23a. Therefore, similar to the first embodiment, the battery device 100a is configured so that the battery stack can be compressed by the pressing jig 200 and housed in the case 30a.

[0081] When the end plate 20a is compressed by the pressing jig 200, the bottom surface S2 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 thickness of the end plate 20a in the stacking direction gradually decreases from the top surface S1 to the bottom surface S2. Therefore, even if the end plate 20a is deformed in accordance with the deformation of the leg pieces 220, the bottom surface S2 of the end plate 20a can be prevented from expanding more than the top surface S1.

[0082] Therefore, the size of the case 30a does not need to be determined in consideration of deformation of the end plate 20a, and the size of the battery device 100a can be reduced.

[0083] 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 uniformly apply the load from the battery stack to the short-side wall portion 32a. In other words, the load is uniform across the entire short-side wall portion 32a.

[0084] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less than one element are also within the scope and spirit of the present disclosure.

[0085] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0086] (Technical Idea 1) A battery device comprising: a battery stack (10) in which a plurality of battery cells (11) are stacked; paired end plates (20) arranged at both ends of the battery stack in the stacking direction; and a case (30) which forms a storage space (34) with a bottom (33) and annular wall portions (31, 32) protruding from the bottom, and which stores the battery stack and the end plates in the storage space, wherein the case has, on an intersecting side wall portion (32) which is part of the annular wall and intersects the stacking direction, a case-side contact surface (321) that contacts the end plates and a case-side recess (323) recessed relative to the case-side contact surface, and the end plates have plate-side contact surfaces (26) that contact the case-side contact surface, and plate-side recesses (23) that face the case-side recess and are recessed relative to the plate-side contact surface.

[0087] (Technical Idea 2) A battery device described in Technical Idea 1, wherein 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, and 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.

[0088] (Technical Idea 3) A battery device described in Technical Idea 1 or 2, wherein the case has a storage bottom surface (S12) which is the surface of the bottom facing the storage space, and an opening end surface (S11) which is the 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) which is the opposite surface of the lower surface, the case side recess is open to the opening end surface side, and the plate side recess is open to the upper surface side.

[0089] (Technical Concept 4) The battery device according to any one of Technical Concepts 1 to 3, wherein the intersecting side wall portion has a chamfered portion (326) at an end portion opposite to the bottom portion.

[0090] (Technical Concept 5) The battery device according to any one of Technical Concepts 1 to 4, wherein the width of the case-side recess and the width of the plate-side recess are different.

[0091] (Technical Idea 6) A battery device described in Technical Idea 2, in which the width of the case side recess and the width of the plate side recess are equal, the spacing between adjacent case side recesses and the spacing between adjacent plate side recesses are equal, and the width of the case side recesses is wider than the spacing between adjacent case side recesses.

[0092] (Technical Idea 7) A battery device described in Technical Idea 2, in which the width of the case side recess and the width of the plate side recess are equal, the spacing between adjacent case side recesses and the spacing between adjacent plate side recesses are equal, and the spacing between adjacent case side recesses is wider than the width of the case side recesses.

[0093] (Technical Idea 8) A battery device described in any one of Technical Ideas 1 to 7, 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.

[0094] (Technical Idea 9) A battery device comprising: a battery stack (10) in which a plurality of battery cells (11) are stacked; paired end plates (20a) arranged at both ends of the battery stack in the stacking direction; and a case (30a) which forms a storage space (34a) with a bottom (33a) and annular wall portions (31a, 32a) protruding from the bottom, and which stores the battery stack and the end plates in the storage space, wherein the case has a crossing side wall portion (32a) that is a part of the annular wall portion and crosses the stacking direction, and the end plates have a plate-side contact surface (26a) in contact with the crossing side wall portion and a plate-side recess (23a) that faces the crossing side wall portion and is recessed into the plate-side contact surface, and the end plates have a lower surface (S2) facing the bottom portion and an upper surface (S1) that is the surface opposite the lower surface, and the plate thickness along the stacking direction gradually decreases from the upper surface to the lower surface.

[0095] (Technical Idea 10) The battery device described in Technical Idea 9, wherein 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 together, and the deformation amount (L2) of the intersecting side wall portion in the stacking direction is equal to or greater than the distance (L1) from the end of the lower surface to the end of the upper surface in the stacking direction of the end plate.

Claims

1. A battery device comprising: a battery stack (10) in which a number of battery cells (11) are stacked; a pair of end plates (20) arranged at both ends in the stacking direction of the battery stack; and a case (30) which defines an accommodation space (34) with a bottom (33) and annular wall portions (31, 32) protruding from the bottom, and which accommodates the battery stack and the end plates in the accommodation space, wherein the case has, on an intersecting side wall portion (32) which is part of the annular wall portion and intersects the stacking direction, a case side contact surface (321) that contacts the end plates and a case side recess (323) that is recessed into the case side contact surface, and the end plates have 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 into the plate side contact surface.

2. A battery device as described in claim 1, wherein 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, and 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. A battery device as described in claim 1 or 2, wherein the case has a storage bottom surface (S12) which is the surface of the bottom portion facing the storage space, and an opening end surface (S11) which is the 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) which is the opposite surface to the lower surface, the case side recess is open to the opening end surface side, and the plate side recess is open to the upper surface side.

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

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

6. A battery device as described in claim 2, wherein the width of the case side recess is equal to the width of the plate side recess, the spacing between adjacent case side recesses is equal to the spacing between adjacent plate side recesses, and the width of the case side recesses is wider than the spacing between adjacent case side recesses.

7. A battery device as described in claim 2, wherein the width of the case side recess and the width of the plate side recess are equivalent, the spacing between adjacent case side recesses and the spacing between adjacent plate side recesses are equivalent, and the spacing between adjacent case side recesses is wider than the width of the case side recesses.

8. A battery device as 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 device comprising: a battery stack (10) in which a number of battery cells (11) are stacked; a pair of end plates (20a) arranged at both ends of the battery stack in the stacking direction; and a case (30a) which defines an accommodation space (34a) with a bottom (33a) and annular wall portions (31a, 32a) protruding from the bottom, and which accommodates the battery stack and the end plates in the accommodation space, wherein the case has a cross side wall portion (32a) which is a part of the annular wall portion and crosses the stacking direction, and the end plates have a plate side contact surface (26a) in contact with the cross side wall portion and a plate side recess (23a) which faces the cross side wall portion and is recessed into the plate side contact surface, and the end plates have a lower surface (S2) which faces the bottom portion and an upper surface (S1) which is the opposite surface to the lower surface, and the plate thickness along the stacking direction gradually becomes thinner from the upper surface to the lower surface.

10. A battery device as described in claim 9, wherein 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 together, and the amount of deformation (L2) of the intersecting side wall portion in the stacking direction is equal to or greater than the distance (L1) from the end of the lower surface to the end of the upper surface in the stacking direction of the end plate.

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