power storage unit

Abstract

An electricity storage unit has an electrode body, a current collecting plate connected to a first electrode sheet, and a laminated film. The outer peripheral edge portion of the current collecting plate includes an inner side edge (68) on the electrode body side and an outer side edge (67) on the opposite side of the electrode body with respect to the inner side edge (68). A welding portion (58A, 58B, 58C) and an adhesive portion (70A, 70B, 70C) are formed in the current collecting plate. When a direction from the inner side edge (68) toward the outer side edge (67) is a first direction (D1) and a direction intersecting the first direction (D1) is a second direction (D2), the welding portion (58A, 58B, 58C) and the adhesive portion (70A, 70B, 70C) are arranged in the second direction (D2). The electricity storage unit of the present application can improve the occupancy of the electrode body in the outer body.

Description

Technical Field

[0001] This disclosure relates to energy storage units. Background Technology

[0002] Energy storage units that consist of an electrode body, a current collector connected to the electrode body, and a laminated film sealing the electrode body have been known for a long time.

[0003] For example, the energy storage unit described in Japanese Patent Application Publication No. 2020-173989 includes an electrode body, an outer casing covering the electrode body, and a current collector connected to the electrode body.

[0004] The electrode body is composed of multiple positive plates, multiple diaphragms, and multiple negative plates stacked together. Positive current collector leads are formed on each positive plate, and negative current collector leads are formed on each negative plate.

[0005] The outer casing is formed of two laminated films. On the short side of the outer casing, a current collector protrudes outwards. Specifically, the current collector protrudes outwards between the two laminated films.

[0006] Within the outer casing, a solder joint and an adhesive joint are formed on the upper surface of the current collector. The solder joint is located within the outer casing and has multiple current collector leads soldered onto it. The adhesive joint is formed on the outer side of the solder joint. The adhesive joint bonds the laminate to the upper surface of the current collector. Summary of the Invention

[0007] In the aforementioned energy storage unit, on the upper surface of the current collector plate, the welded and adhesive portions are arranged along the direction in which the current collector plate protrudes from the outer casing to the outside of the outer casing. Therefore, a space is created between the welded and adhesive portions within the outer casing. As a result, the occupancy of the electrode body within the outer casing is reduced.

[0008] The energy storage unit disclosed herein was made in view of the above-mentioned problems, and its purpose is to provide an energy storage unit that can increase the occupancy of the electrode body in the outer casing.

[0009] The energy storage unit disclosed herein includes an electrode body, a current collector plate, and a laminated film. The electrode body is formed by stacking a first electrode sheet, a separator, and a second electrode sheet. The current collector plate is configured to be adjacent to the electrode body and connected to the first electrode sheet. The laminated film seals the electrode body and the current collector plate inside it. The outer peripheral portion of the current collector plate includes an inner side located on the electrode body side and an outer side located on the opposite side of the electrode body relative to the inner side. The current collector plate forms a welded portion for welding to the first electrode sheet and at least one adhesive portion for bonding the laminated film. When the direction from the inner side to the outer side is taken as a first direction and the direction intersecting the first direction is taken as a second direction, the welded portion and the adhesive portion are arranged in the second direction.

[0010] Based on the above-mentioned energy storage unit, it is possible to suppress the waste space generated in the laminated film and to increase the occupancy rate of the electrode body in the laminated film.

[0011] The aforementioned laminated film includes a first film covering one side of the electrode body and a second film covering the other side of the electrode body. The energy storage unit further includes a welded portion that fuses the outer periphery of the first film and the outer periphery of the second film. The welded portion is located outside the current collector and the electrode body, and is formed in a ring shape along the outer periphery of the first film and the outer periphery of the second film.

[0012] The aforementioned adhesive portions are formed in a plurality of open-spaced manner in the second direction, and welding portions are disposed between the adhesive portions.

[0013] A hole is formed in the aforementioned adhesive portion, exposing a portion of the current collector plate. An exposure hole is formed in the portion of the laminate where the hole is located, and a portion of the current collector plate is formed to be exposed to the outside through the hole and the exposure hole.

[0014] The above and other objects, features, aspects and advantages of this disclosure will become apparent from the following detailed description of this disclosure, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a perspective view schematically showing the energy storage device 1, etc., according to this embodiment.

[0016] Figure 2 yes Figure 1 A cross-sectional view of line II-II.

[0017] Figure 3 It is a schematic 3D view showing the energy storage module 20 and the busbars 21, 22, etc.

[0018] Figure 4 This is a three-dimensional view representing the energy storage unit 30.

[0019] Figure 5 This is an exploded perspective view of the energy storage unit 30.

[0020] Figure 6 This is a schematic 3D diagram representing the positive electrode 50.

[0021] Figure 7 This is a schematic top view of the negative electrode 52.

[0022] Figure 8 This is a top view showing the main surface 46 of the positive current collector 37 and the surrounding structure.

[0023] Figure 9 This is a top view showing the main surface 47 of the positive current collector 37.

[0024] Figure 10 This is a top view showing the main surface 48 of the negative current collector 38.

[0025] Figure 11 This is a top view showing the main surface 49 of the negative current collector plate 38.

[0026] Figure 12 This is a cross-sectional view of the energy storage unit 30.

[0027] Figure 13 This is a top view showing the exposed hole 96A and hole portion 71A.

[0028] Figure 14 This is a perspective view of the comparative example, energy storage unit 30A.

[0029] Figure 15 This is a cross-sectional view showing the 30A energy storage unit.

[0030] Figure 16 This is a 3D diagram representing the 50A positive electrode.

[0031] Figure 17 This is a 3D diagram representing the negative electrode 52A.

[0032] Figure 18 This is a top view showing the main surface 46A of the positive current collector 37A.

[0033] Figure 19 This is a top view showing the main surface 48A of the negative current collector 38A. Detailed Implementation

[0034] use Figures 1 to 19 The energy storage unit and energy storage device of this embodiment will be described. Figures 1 to 19 In the structures shown, the same symbols are assigned to the same or substantially the same structures, and repeated descriptions are omitted.

[0035] Figure 1 This is a perspective view schematically showing the energy storage device 1 of this embodiment. The battery pack 100 includes the energy storage device 1 and cooling devices 5 and 6. The energy storage device 1 includes a housing 2, a positive external terminal 3, and a negative external terminal 4.

[0036] The housing 2 is generally rectangular. The housing 2 includes a top plate 10, a bottom plate 11, side walls 12 and 13, and end walls 14 and 15. Side walls 12 and 13 are arranged in the width direction W and extend in the length direction L. End walls 14 and 15 are arranged in the length direction L and extend in the width direction W.

[0037] Positive external terminal 3 and negative external terminal 4 are provided on the upper surface of top plate 10. Positive external terminal 3 and negative external terminal 4 are arranged at an open interval in the width direction W.

[0038] Cooling device 5 is disposed on side wall 12, and cooling device 6 is disposed on side wall 13. Coolant C flows within cooling devices 5 and 6. Furthermore, in Figure 1 In the image, a portion of cooling devices 5 and 6 is viewed in cross-section, with some parts omitted.

[0039] Figure 2 yes Figure 1 A cross-sectional view of line II-II. The energy storage device 1 includes an energy storage module 20, busbars 21 and 22 connected to the energy storage module 20, expansion-absorbing materials 23 and 24, insulating components 25 and 26, and an insulating film 27.

[0040] Figure 3 This is a perspective view schematically showing the energy storage module 20 and busbars 21, 22, etc. The energy storage module 20 includes multiple energy storage units 30, 31, 32 and multiple connecting members 33, 34 stacked in the stacking direction H.

[0041] The structures of energy storage units 31 and 32 are essentially the same as those of energy storage unit 30, so energy storage unit 30 will be described in detail.

[0042] Figure 4 This is a 3D view showing the energy storage unit 30. Figure 5 This is an exploded perspective view of the energy storage unit 30. The energy storage unit 30 includes an electrode body 35, a laminated film 36, a positive current collector 37, and a negative current collector 38.

[0043] The laminate 36 is a stacked structure of resin film, aluminum foil and resin film. The laminate 36 seals the electrode body 35, positive current collector 37, negative current collector 38 and electrolyte (not shown) inside.

[0044] The electrode body 35 is generally rectangular parallelepiped in shape. The electrode body 35 includes an upper surface 40, a lower surface 41, side surfaces 42 and 43, and end faces 44 and 45. Side surfaces 42 and 43 are arranged in the width direction W and extend in the length direction L. End faces 44 and 45 are arranged in the length direction L and extend in the width direction W. Furthermore, the length L of the side surfaces 42 and 43 is longer than the length W of the end faces 44 and 45.

[0045] The positive current collector 37 is located on the side 42 of the electrode body 35, and the negative current collector 38 is located on the side 43 of the electrode body 35.

[0046] The electrode body 35 includes a plurality of positive electrode plates 50, a plurality of separators 51, and a plurality of negative electrode plates 52 stacked in the stacking direction H. Furthermore, the plates are stacked such that the separators 51 are disposed between the positive electrode plates 50 and the negative electrode plates 52.

[0047] Figure 6 This is a schematic perspective view of the positive electrode 50. The positive electrode 50 includes an aluminum foil 54 and a positive electrode binder layer 55 formed on both sides of the aluminum foil 54.

[0048] The aluminum foil 54 is formed into a rectangular shape. An uncoated portion 56 is formed on one long side of the aluminum foil 54 without a positive electrode coating layer 55.

[0049] The aluminum foil 54 includes connecting tabs 57 formed on the uncoated portion 56. Multiple connecting tabs 57 are formed at intervals in the direction in which the aluminum foil 54 extends.

[0050] Figure 7 This is a schematic perspective view of the negative electrode 52. The negative electrode 52 includes a copper foil 60 and a negative electrode adhesive layer 61 formed on both sides of the copper foil 60. The copper foil 60 is formed in a rectangular shape, and an uncoated portion 62 of the uncoated negative electrode adhesive layer 61 is formed on one long side of the copper foil 60. The negative electrode 52 includes a connector 63 formed on the uncoated portion 62. The connector 63 is formed at intervals in the direction in which the copper foil 60 extends.

[0051] return Figure 5 The positive current collector 37 is located on the side 42 of the electrode body 35, and the negative current collector 38 is located on the side 43 of the electrode body 35.

[0052] Here, in the length direction L, the positive current collector 37 is formed to extend from one end of the side 42 to the other end. Similarly, the negative current collector 38 is formed to extend from one end of the side 43 to the other end. Therefore, the positive current collector 37 and the negative current collector 38 are formed elongated in the length direction L.

[0053] The positive electrode current collector 37 is formed in the shape of a flat plate, and includes a main surface 46 and a main surface 47. The main surface 46 is the upper surface, and the main surface 47 is the lower surface. Connecting pieces 57 formed on each positive electrode sheet 50 are welded to the main surface 46.

[0054] Figure 8 This is a top view showing the main surface 46 of the positive current collector 37 and the surrounding structure.

[0055] Multiple adhesive materials 70A, 70B, 70C, and 70D are formed on the main surface 46 of the positive current collector plate 37 at open intervals. Each adhesive material 70A, 70B, 70C, and 70D is formed at open intervals in the length direction L.

[0056] Adhesive materials 70A, 70B, 70C, and 70D are essentially the same; however, adhesive material 70A will be described in detail.

[0057] The adhesive material 70A is formed of a thermoplastic resin or the like. A hole 71A is formed in the adhesive material 70A, and a portion of the main surface 46 is exposed from the hole 71A. Through holes 72A and 73A are formed in the portion of the positive current collector plate 37 exposed from the hole 71A. Furthermore, the through holes 72A and 73A are formed at an open interval along the longitudinal direction L. The through holes 72A and 73A are formed to extend from the main surface 46 to the main surface 47.

[0058] Holes 71B, 71C, and 71D are also formed in the adhesive materials 70B, 70C, and 70D. Through holes 72B, 73B, 72C, 73C, 72D, and 73D are formed in the portion of the positive electrode current collector plate 37 that is exposed from the holes 71B, 71C, and 71D.

[0059] Furthermore, multiple connecting pieces 57 are fused to the portions of the main surface 46 located between the various adhesive materials 70A, 70B, 70C, and 70D. For example, multiple connecting pieces 57 are welded together between adhesive materials 70A and 70B via welding portions 58A. Between adhesive materials 70B and 70C, and between adhesive materials 70C and 70D, multiple connecting pieces 57 are fused to the main surface 46 via welding portions 58B and 58C, respectively.

[0060] The positive current collector 37 includes an outer side 67 and an inner side 68, as well as short sides 28 and 29. The outer side 67 and the inner side 68 are formed to extend along the length direction L. The outer side 67 is located at one end in the width direction W, and the inner side 68 is located at the other end in the width direction W. The inner side 68 is located on the electrode body 35 side, and the outer side 67 is located on the side opposite to the electrode body 35 relative to the inner side 68. The short side 28 is located at one end in the length direction L, and the short side 29 is located at the other end in the length direction L. The short sides 28 and 29 are formed to extend along the width direction W. Here, the direction from the inner side 68 toward the outer side 67 is designated as direction D1, and the direction intersecting direction D1 is designated as direction D2. Furthermore, in this embodiment, direction D2 is the length direction L.

[0061] The adhesive materials 70A, 70B, 70C, 70D and the welded parts 58A, 58B, 58C are arranged in direction D2. In other words, the adhesive materials 70A, 70B, 70C, 70D and the welded parts 58A, 58B, 58C are arranged along the outer edge 67 of the positive electrode current collector 37 in the length direction L.

[0062] Furthermore, the welding part 58A is disposed between the adhesive material 70A and the adhesive material 70B, and the welding parts 58B and 58C are disposed in the same manner.

[0063] Figure 9 This is a top view of the main surface 47 of the positive current collector 37. Multiple adhesive materials 75A, 75B, 75C, and 75D are also formed at intervals along the length direction L on the main surface 47.

[0064] Holes 76A, 76B, 76C, and 76D are formed in each of the adhesive materials 75A, 75B, 75C, and 75D. A portion of the main surface 47 is exposed from each of the holes 76A, 76B, 76C, and 76D. Furthermore, through holes 72A and 73A are formed in the portion of the main surface 47 exposed from hole 76A. Similarly, through holes 72B, 73B, 72C, 73C, 72D, and 73D are formed in the portion of the main surface 47 exposed from holes 76B, 76C, and 76D.

[0065] Here, Figure 8 The adhesive material 70A shown is... Figure 9 The adhesive material 75A shown is formed such that the positive current collector 37 is sandwiched between them and they are opposite each other. That is, the adhesive material 75A is placed below the adhesive material 70A. Similarly, each adhesive material 70B, 70C, 70D is arranged opposite to each adhesive material 75B, 75C, 75D.

[0066] Figure 10 This is a top view showing the main surface 48 of the negative current collector plate 38. Figure 11 This is a top view showing the main surface 49 of the negative current collector 38. In the negative current collector 38, similar to the positive current collector 37, multiple adhesive materials are formed.

[0067] The negative current collector 38 includes an outer side 59, an inner side 69, a short side 19, and a short side 89. The outer side 59 is located at one end in the width direction W, and the inner side 69 is located at the other end in the width direction W. The short side 19 is located at one end in the length direction L, and the short side 89 is located at the other end in the length direction L.

[0068] Here, the direction from the inner side 69 to the outer side 59 is designated as direction D3, and the direction intersecting with direction D3 is designated as direction D4. Furthermore, direction D4 is the length direction L.

[0069] On the main surface 48, multiple adhesive materials 77A, 77B, 77C, 77D and multiple welded parts 58D, 58E, 58F are arranged in the direction D4.

[0070] Furthermore, each adhesive material 77A, 77B, 77C, and 77D is formed in a spaced manner in direction D4 (length direction L), and each welded part 58D, 58E, and 58F is formed between adhesive materials 77A, 77B, 77C, and 77D.

[0071] exist Figure 11 In the main surface 49, multiple adhesive materials 78A, 78B, 78C, and 78D are formed at intervals along the length direction L. Adhesive materials 77A and 78A are arranged opposite each other, with the negative current collector 38 sandwiched between them. Similarly, adhesive materials 77B and 78B are opposite each other, adhesive materials 77C and 78C are opposite each other, and adhesive materials 77D and 78D are opposite each other.

[0072] Holes 80A, 80B, 80C, and 80D are formed in each of the adhesive materials 77A, 77B, 77C, and 77D, and holes 81A, 81B, 81C, and 81D are formed in each of the adhesive materials 78A, 78B, 78C, and 78D.

[0073] Multiple through holes 83A, 84A, 83B, 84B, 83C, 84C, 83D, and 84D are formed in the negative electrode current collector plate 38. Through holes 83A and 84B are formed in the portions of the negative electrode current collector plate 38 that are exposed from the holes 80A and 81A. Similarly, through holes 83B, 84B, 83C, 84C, 83D, and 84D are formed in the portions of the negative electrode current collector plate 38 that are exposed from the holes 80B, 81B, 80C, 81C, 80D, and 81D.

[0074] return Figure 5 The laminated film 36 includes an upper film 39A and a lower film 39B. The upper film 39A is configured to cover the electrode body 35, the positive current collector 37, and the negative current collector 38 from above. The lower film 39B is configured to cover the electrode body 35, the positive current collector 37, and the negative current collector 38 from below. The upper film 39A includes a covering portion 85A and an outer peripheral portion 86A.

[0075] An outer peripheral portion 86A is formed on the outer peripheral edge of the covering portion 85A, and the outer peripheral portion 86A is formed in a ring shape. The covering portion 85A is formed in a way that protrudes upward, so as to cover the electrode body 35 from above.

[0076] The outer peripheral portion 86A includes a shoulder 87A, a shoulder 88A, and connecting pieces 90A and 91A. The shoulders 87A and 88A are formed to extend along the length direction L. The connecting piece 90A is formed to connect one end of the shoulder 87A and one end of the shoulder 88A. The connecting piece 91A is formed to connect the other end of the shoulder 87A and the other end of the shoulder 88A.

[0077] The shoulder 87A is disposed on the main surface 46 of the positive current collector plate 37, and the shoulder 88A is disposed on the main surface 48 of the negative current collector plate 38.

[0078] Multiple exposed holes 92A, 93A, 94A, and 95A are formed at intervals along the length direction L of the shoulder portion 87A. The shoulder portion 87A is arranged such that each exposed hole 92A, 93A, 94A, and 95A is located on the adhesive materials 70A, 70B, 70C, and 70D. The adhesive materials 70A, 70B, 70C, and 70D bond the shoulder portion 87A to the positive electrode current collector plate 37. Furthermore, a portion of the main surface 46 of the positive electrode current collector plate 37 is exposed to the outside through the exposed holes 92A, 93A, 94A, 95A and the holes 71A, 71B, 71C, and 71D.

[0079] Multiple exposed holes 96A, 97A, 98A, and 99A are also formed at intervals along the length direction L on the shoulder portion 88A. Furthermore, the shoulder portion 88A is arranged such that the exposed holes 96A, 97A, 98A, and 99A are located on the adhesive materials 77A, 77B, 77C, and 77D. A portion of the main surface 48 is exposed to the outside through the exposed holes 96A, 97A, 98A, and 99A and the holes 80A, 80B, 80C, and 80D. The adhesive materials 77A, 77B, 77C, and 77D bond the shoulder portion 88A to the negative electrode current collector plate 38.

[0080] The lower membrane 39B is constructed in the same manner as the upper membrane 39A. The lower membrane 39B includes a shoulder 87B, a shoulder 88B, and connecting pieces 90B and 91B. The shoulder 87B is disposed on the main surface 47 of the positive current collector plate 37, and the shoulder 88B is disposed on the main surface 49 of the negative current collector plate 38.

[0081] Multiple exposed holes 92B, 93B, 94B, and 95B are formed at intervals along the length direction L of the shoulder portion 87B. The shoulder portion 87B is arranged such that each exposed hole 92B, 93B, 94B, and 95B is located on the adhesive materials 75A, 75B, 75C, and 75D. Furthermore, a portion of the main surface 47 is exposed through the exposed holes 92B, 93B, 94B, and 95B and the holes 76A, 76B, 76C, and 76D. The adhesive materials 75A, 75B, 75C, and 75D bond the shoulder portion 87B to the positive current collector plate 37.

[0082] Multiple exposed holes 96B, 97B, 98B, and 99B are formed at intervals along the length direction L of the shoulder portion 88B. Furthermore, the shoulder portion 88B is arranged such that the exposed holes 96B, 97B, 98B, and 99B are located on the adhesive materials 78A, 78B, 78C, and 78D. A portion of the main surface 49 is exposed to the outside through the exposed holes 96B, 97B, 98B, and 99B and the holes 81A, 81B, 81C, and 81D. The adhesive materials 78A, 78B, 78C, and 78D bond the shoulder portion 88B to the negative electrode current collector plate 38.

[0083] Figure 12 This is a cross-sectional view showing the energy storage unit 30. Figure 12 In the middle, the outer peripheral edge of the outer peripheral portion 86A and the outer peripheral edge of the outer peripheral portion 86B are located on the outer side of the specific electrode body 35, the positive electrode current collector 37 and the negative electrode current collector 38.

[0084] The outer peripheral edges of the lower surface of the outer peripheral portion 86A and the lower peripheral edges of the outer peripheral portion 86B are bonded together at the welded portion 16. The welded portion 16 is formed in a ring-shaped extension manner. Thus, the electrode body 35, the positive electrode current collector 37, the negative electrode current collector 38, and the electrolyte (not shown) are sealed within the laminated film 36.

[0085] Thus, the positive current collector 37 and the negative current collector 38 are not formed to protrude between the upper membrane 39A and the lower membrane 39B. Therefore, no gap is formed between the positive current collector 37 and the negative current collector 38 and the laminated membrane 36 on the side of the positive current collector 37. As a result, leakage of electrolyte from the energy storage unit 30 to the outside can be suppressed, and foreign matter intrusion into the energy storage unit 30 can be suppressed.

[0086] exist Figure 12 In the positive electrode current collector 37, a portion of the main surface 46 is exposed through the exposure hole 92A and the hole portion 71A. A portion of the main surface 47 is exposed through the exposure hole 92B and the hole portion 76A. Furthermore, in the negative electrode current collector 38, portions of the main surfaces 48 and 49 are exposed from the laminate 36.

[0087] Figure 13 This is a top view showing the exposed hole 92A and the hole portion 71A. The hole portion 71A of the adhesive material 70A extends along the exposed hole 92A of the shoulder portion 87A, and the adhesive material 70A is formed along the exposed hole 92A. The opening area of ​​the exposed hole 96A is larger than the opening area of ​​the hole portion 71A. Moreover, when viewed from a position away from the lamination direction H, the hole portion 71A is located within the exposed hole 92A. As a result, foreign matter intrusion into the laminated film 36 is suppressed.

[0088] As described above, the energy storage unit 30 has been explained, but the energy storage units 31 and 32 are also constructed in the same manner as the energy storage unit 30.

[0089] exist Figure 2 and Figure 3 In the energy storage unit 31, there are electrode bodies 135, laminated film 136, positive current collector 137, and negative current collector 138. Furthermore, in the energy storage unit 31, the positive current collector 137 includes a pair of main surfaces, each main surface having a portion exposed from the laminated film 136. Similarly, each main surface of the negative current collector 138 has a portion exposed from the laminated film 136.

[0090] The energy storage unit 32 includes an electrode body 235, a laminated film 236, a positive current collector 237, and a negative current collector 238. A portion of the laminated film 236 is formed on each main surface of the positive current collector 237. A portion of the laminated film 236 is also formed on each main surface of the negative current collector 238.

[0091] On side 42 of electrode body 35, positive electrode current collector 37, negative electrode current collector 138 and positive electrode current collector 237 are arranged in the stacking direction H. On side 43, negative electrode current collector 38, positive electrode current collector 137 and negative electrode current collector 238 are arranged in the stacking direction H.

[0092] The portion of busbar 21 exposed from the laminate 36 in the negative current collector plate 38 is fused together. The portion of busbar 22 exposed from the laminate 236 in the positive current collector plate 237 is fused together. Furthermore, busbar 21 is connected to the negative external terminal 4, and busbar 22 is connected to the positive external terminal 3.

[0093] The connecting member 33 is formed to extend along the length direction L. The connecting member 33 is disposed between the positive current collector 37 and the negative current collector 138, connecting the positive current collector 37 and the negative current collector 138.

[0094] The portion of the connecting member 33 exposed from the laminate 36 in the positive electrode current collector 37 is fused together, and the portion of the connecting member 33 exposed from the laminate 136 in the negative electrode current collector 138 is fused together.

[0095] A connecting member 34 is disposed between the positive current collector 137 and the negative current collector 238, connecting the positive current collector 137 and the negative current collector 238. The portion of the connecting member 34 exposed in the laminate 136 within the positive current collector 137 is fused together.

[0096] Thus, the energy storage units 30, 31 and 32 are connected in series to the ground via the connecting member 33 and the connecting member 34.

[0097] The insulating member 25 is filled in such a way that it extends from the side wall 12 to the energy storage module 20. Moreover, the insulating member 25 is formed to contact the connecting member 33 and cover the positive current collector 37, the negative current collector 138 and the positive current collector 237.

[0098] Therefore, when the energy storage device 1 is charging and discharging, causing the energy storage module 20 to heat up, the heat of the energy storage module 20 can be dissipated to the cooling device 5 through the connecting member 33, the positive current collector 37, the negative current collector 138, the positive current collector 237 and the insulating member 25.

[0099] The insulating member 26 is filled in such a way that it extends from the side wall 13 to the energy storage module 20. The insulating member 26 is formed to contact the connecting member 34 and covers the negative current collector 38, the positive current collector 137, and the negative current collector 238. Therefore, the heat of the energy storage module 20 can be effectively dissipated to the cooling device 6.

[0100] The expansion-absorbing materials 23 and 24 comprise expansion-forming materials and sealing members that seal the expansion-forming materials. Expansion-absorbing material 23 is disposed between the energy storage module 20 and the top plate 10, and expansion-absorbing material 24 is disposed between the energy storage module 20 and the bottom plate 11.

[0101] Furthermore, during the charging and discharging of the energy storage device 1, the energy storage module 20 deforms by expanding in the stacking direction H. The deformation rate of the energy storage module 20 is small, so the expansion-absorbing materials 23 and 24 deform in a manner that allows the deformation of the energy storage module 20.

[0102] Therefore, even if the energy storage module 20 deforms by expanding, the load applied to the housing 2 can be suppressed, and the deformation of the housing 2 can be suppressed.

[0103] On the other hand, when the battery pack 100 is mounted in a vehicle or the like, vibrations are applied to the energy storage device 1 when the vehicle is in motion. When the energy storage device 1 vibrates, for example, it sometimes vibrates with its center as an antinode.

[0104] At this time, the deformation speed of the energy storage device 1 during vibration is faster than the deformation speed of the energy storage module 20 due to charging and discharging.

[0105] Thus, under high deformation speeds, the rigidity of the expansion-absorbing materials 23 and 24, which contain the expansion-molding material, becomes higher, making them less prone to deformation. As a result, vibration of the energy storage device 1 can be suppressed.

[0106] Figure 14 This is a perspective view of the energy storage unit 30A, a comparative example. The energy storage unit 30A includes an electrode body 35A, a laminated film 36A, a positive current collector 37A, and a negative current collector 38A.

[0107] The outer periphery of the laminate 36A is approximately rectangular in shape. The outer periphery of the laminate 36A includes long sides 305 and 306 and short sides 307 and 308.

[0108] The positive current collector 37A protrudes from the short side 307 to the outside of the laminate 36A, and the negative current collector 38A protrudes from the short side 308 to the outside of the laminate 36A.

[0109] Figure 15 This is a cross-sectional view of the energy storage unit 30A. The electrode body 35A includes multiple positive electrode plates 50A, multiple separators 51A, and multiple negative electrode plates 52A.

[0110] Figure 16 This is a three-dimensional diagram representing the positive electrode 50A. The positive electrode 50A includes an aluminum foil 54A and a positive electrode flux layer 55A.

[0111] A positive electrode flux layer 55A is formed on both sides of an aluminum foil 54A. The aluminum foil 54A is formed in a rectangular shape. Furthermore, an uncoated portion 56A, where the positive electrode flux layer 55A is not coated, is formed on the aluminum foil 54A. The uncoated portion 56A is formed on the short side of the aluminum foil 54A. The positive electrode sheet 50A includes a connecting piece 57A protruding from the uncoated portion 56A.

[0112] Figure 17 This is a perspective view of the negative electrode 52A. The negative electrode 52A includes a copper foil 60A and a negative electrode flux layer 61A. The negative electrode flux layer 61A is formed on both sides of the copper foil 60A. The copper foil 60A is also formed in a rectangular shape. An uncoated portion 62A, where the negative electrode flux layer 61A is not formed, is formed on the short side of the copper foil 60A. The negative electrode 52A includes a connecting piece 63A protruding from the uncoated portion 62A.

[0113] return Figure 15 The laminate 36A comprises an upper membrane 304A and a lower membrane 304B.

[0114] The upper membrane 304A is configured to cover the electrode body 35A from above, and the lower membrane 304B is configured to cover the electrode body 35A from below.

[0115] The positive current collector 37A is formed in the shape of a plate, and includes a main surface 46A and a main surface 47A. The main surface 46A is the upper surface, and the main surface 47A is the lower surface.

[0116] A welding part 310 and an adhesive material 300 are formed on the main surface 46A of the positive electrode current collector 37A, and an adhesive material 301 is formed on the main surface 47A.

[0117] Furthermore, multiple connecting pieces 57A are welded to the welding section 310. Adhesive material 300 bonds the upper membrane 304A and the positive current collector plate 37A. Adhesive material 301 bonds the lower membrane 304B and the positive current collector plate 37A. Adhesive materials 300 and 301 are arranged opposite each other, with the positive current collector plate 37A sandwiched between them.

[0118] A welding portion 311 and an adhesive material 302 are formed on the main surface 48A of the negative electrode current collector 38A, and an adhesive material 303 is formed on the main surface 49A. The adhesive materials 302 and 303 are arranged opposite each other, sandwiching the negative electrode current collector 38A between them. The welding portion 311 welds multiple connecting pieces 63A to the main surface 48A. The adhesive material 302 adheres the upper film 304A to the negative electrode current collector 38A, and the adhesive material 303 adheres the lower film 304B to the negative electrode current collector 38A.

[0119] Figure 18 This is a top view showing the main surface 46A of the positive current collector 37A. The adhesive material 300 is located on the outer side 67A, and the welded part 310 is located on the inner side 68A. Here, a space is formed between the adhesive material 300 and the welded part 310 in the direction D1 from the inner side 68A to the outer side 67A.

[0120] On the other hand, such as Figure 8 As shown, in the energy storage unit 30 of this embodiment, adhesive material 70A, welding part 58A, adhesive material 70B, welding part 58B, adhesive material 70C, welding part 58C, and adhesive material 70D are arranged along direction D2.

[0121] Therefore, in direction D1, the space formed by the adhesive materials 70A, 70B, 70C, 70D and the welded parts 58A, 58B, 58C is suppressed.

[0122] Therefore, in the energy storage unit 30 of this embodiment, the occupancy rate of the electrode body 35 in the laminated film 36 is greater than the occupancy rate of the electrode body 35A in the energy storage module 20A of the comparative example.

[0123] Furthermore, in Figure 8 In the middle, welding parts 58A, 58B, and 58C are formed at intervals, and multiple connecting pieces 57 are welded to the positive electrode current collector plate 37 through each welding part 58A, 58B, and 58C.

[0124] Therefore, during charging and discharging, the current distribution within each positive electrode 50 can be made uniform, and the generation of localized deterioration within the positive electrode 50 can be suppressed.

[0125] Figure 19 This is a top view showing the main surface 48A of the negative current collector plate 38A. Here, in the direction D3 from the inner side 69A to the outer side 59A, the adhesive material 302 and the welded part 311 are arranged with a gap between each other. Therefore, a space is formed between the adhesive material 302 and the welded part 311 in the direction D3.

[0126] On the other hand, such as Figure 10 As shown, in the energy storage unit 30, multiple adhesive materials 77A, 77B, 77C, 77D and multiple welded portions 58D, 58E, 58F are arranged in direction D4, thus suppressing the formation of spaces in direction D3. Therefore, in the energy storage unit 30 of this embodiment, the occupancy rate of the electrode body 35 within the laminated film 36 can be increased. Furthermore, while the above embodiment describes an example of storing electrolyte in each energy storage unit, the technology of this disclosure can also be provided when solid-state batteries are used in each energy storage unit.

[0127] While embodiments of this disclosure have been described, they should be considered illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims and is intended to include all modifications within the equivalent meaning and scope of the claims.

Claims

1. An energy storage unit comprising an electrode body, a current collector, and a laminated film, The electrode body is formed by stacking a first electrode sheet, a diaphragm, and a second electrode sheet, and has a side extending in the length direction. The current collector is configured to be adjacent to the side of the electrode body, extending from one end of the side to the other, and connected to the first electrode plate. The laminated film seals the electrode body, the current collector, and the electrolyte inside. The outer peripheral portion of the current collector includes: an inner side located on the electrode body side, and an outer side located on the opposite side of the electrode body relative to the inner side. The current collector plate forms a welding portion for welding to the first electrode sheet, and at least one adhesive portion for bonding the laminate film. When the direction from the inner side to the outer side is taken as the first direction, and the direction intersecting the first direction, i.e. the length direction, is taken as the second direction, the welded portion and the adhesive portion are arranged in the second direction.

2. The energy storage unit according to claim 1, The laminated film includes a first film covering one side of the electrode body and a second film covering the electrode body from the other side. It also includes a welding portion for fusing the outer periphery of the first membrane and the outer periphery of the second membrane. The welded portion is located on the outer side of the current collector and the electrode body, and is formed in a ring shape along the outer periphery of the first film and the outer periphery of the second film.

3. The energy storage unit according to claim 1 or 2, The adhesive portions are formed in a plurality of spaced-apart configurations in the second direction. The welded portion is disposed between the adhesive portions.

4. The energy storage unit according to claim 1 or 2, A hole is formed in the adhesive portion, exposing a portion of the current collector. The portion of the laminated film where the pores are located has exposed pores. A portion of the current collector is formed to be exposed externally through the holes and the exposed holes.

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