Battery cell, battery module, and battery cell manufacturing method

Abstract

To provide a battery cell with high volumetric efficiency.SOLUTION: A battery cell includes: an electrode assembly in which a positive electrode and a negative electrode are alternately stacked in a first direction; a first current collector unit connected to at least one positive electrode; a second current collector unit connected to at least one negative electrode; and an exterior case that accommodates the electrode assembly, the first current collector unit, and the second current collector unit. The exterior case includes a first casing body and a second casing body. At least a portion of the first current collector unit is located between the first casing body and the electrode assembly in the first direction, and is electrically connected to the first casing body. At least a portion of the second current collector unit is located between the second casing body and the electrode assembly in the first direction, and is electrically connected to the second casing body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery cell, a battery module, and a method for manufacturing a battery cell. [Background technology]

[0002] Various types of battery cells have been known in the past. For example, Japanese Patent Laid-Open Publication No. 2005-310618 (Patent Document 1) discloses a nonaqueous electrolyte secondary battery as one such battery cell. This nonaqueous electrolyte secondary battery includes an electrode plate assembly formed by spirally winding a positive electrode plate having an active material coated on a strip-shaped current collector and a negative electrode plate having an active material coated on a strip-shaped current collector with a separator interposed therebetween. The electrode plate assembly is inserted into a metal exterior case together with a nonaqueous electrolyte. The outermost periphery of the electrode plate assembly is made of a positive electrode current collector that is not coated with an active material. The positive electrode current collector is in contact with the inner wall of the exterior case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-310618 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery cell disclosed in Patent Document 1, the negative electrode current collector (negative electrode current collector) is not in contact with the exterior case, which means there is room for further improvement in volumetric efficiency.

[0005] The present disclosure provides a battery cell with high volumetric efficiency, a battery module including the battery cell, and a method for manufacturing the battery cell. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a battery cell includes an electrode assembly in which positive electrodes and negative electrodes are alternately stacked in a first direction, a first current collector connected to at least one positive electrode, a second current collector connected to at least one negative electrode, and an exterior case that houses the electrode assembly, the first current collector, and the second current collector. The exterior case includes a first case body and a second case body. At least a portion of the first current collector is located between the first case body and the electrode assembly in the first direction and is electrically connected to the first case body. At least a portion of the second current collector is located between the second case body and the electrode assembly in the first direction and is electrically connected to the second case body.

[0007] With this configuration, the first current collecting portion allows the first case body of the exterior case to function as a positive terminal, and the second current collecting portion allows the second case body of the exterior case to function as a negative terminal.

[0008] Furthermore, the first current collecting portion is connected to the first case body at a portion located between the first case body and the laminated electrode body in the first direction. The second current collecting portion is connected to the second case body at a portion located between the lid and the laminated electrode body in the first direction. Therefore, the first current collecting portion and the second current collecting portion can be brought into contact with the exterior case at positions spaced apart from each other in the first direction.

[0009] Therefore, the battery cell can achieve higher volumetric efficiency than a battery cell configuration in which only one of the positive electrode current collecting portion and the negative electrode current collecting portion is in contact with the outer case.

[0010] Preferably, the first case body has a first base to which at least a portion of the first current collector is connected and a first sidewall extending from the outer periphery of the first base in a first direction toward the electrode assembly. The second case body faces the first base and has a second base to which at least a portion of the second current collector is connected and a second sidewall extending from the outer periphery of the second base in a second direction opposite to the first direction. The first sidewall and the second sidewall partially overlap when viewed from a second direction perpendicular to the first direction.

[0011] With this configuration, the laminated electrode body 3, the first current collecting portion, the second current collecting portion, and the insulating material can be reliably sealed within the exterior case.

[0012] Preferably, an insulating material is filled between the first side wall portion and the second side wall portion.

[0013] With this configuration, it is possible to prevent a short circuit between the first case body and the second case body of the exterior case.

[0014] Preferably, the first current collector includes a plurality of first current collector foils, each connected to a different positive electrode. Each first current collector foil has a first portion extending from the positive electrode toward the first base portion and a second portion continuous with the first portion and extending parallel to the first base portion between the first base portion and the electrode body. The second portion is electrically connected to the first case body and faces the negative electrode in the first direction. The second portion is insulated from the negative electrode facing the second portion in the first direction.

[0015] With this configuration, it is possible to prevent a short circuit between the first current collecting portion and the negative electrode that faces a part of the first current collecting portion in the first direction.

[0016] Preferably, the second current collector includes a plurality of second current collector foils, each connected to a different negative electrode. Each second current collector foil has a first portion extending from the negative electrode toward the second base portion and a second portion continuous with the first portion and extending parallel to the second base portion between the second base portion and the electrode body. The second portion is electrically connected to the second case body and faces the positive electrode in the first direction. The second portion is insulated from the positive electrode facing the second portion in the first direction.

[0017] With this configuration, it is possible to prevent a short circuit between the second current collecting portion and the positive electrode that a part of the second current collecting portion faces in the first direction.

[0018] Preferably, the electrode assembly further includes a separator layer containing a solid electrolyte between the positive electrode and the negative electrode.

[0019] According to this configuration, there is no need to inject an electrolyte into the exterior case, so that the discharge and charge of the electrode body can be inspected before the electrode body is housed in the exterior case 2.

[0020] Preferably, one of the first case body and the second case body is a main body of the outer case, and the other is a lid of the outer case.

[0021] According to this configuration, the electrode body can be housed in the exterior case by covering one of the first case body and the second case body, which functions as the main body, with the other.

[0022] According to another aspect of the present disclosure, a battery module includes a plurality of the above-described battery cells, and the battery cells are stacked in the first direction.

[0023] With this configuration, the volumetric efficiency of the battery cells can be improved, and therefore the volumetric efficiency of the battery module can be improved.

[0024] According to yet another aspect of the present disclosure, a method for manufacturing a battery cell includes the steps of: placing a battery cell having an electrode body in which positive electrodes and negative electrodes are alternately stacked in a first direction, a first current collecting portion connected to at least one positive electrode, and a second current collecting portion connected to at least one negative electrode, so that the first current collecting portion contacts a first case body of an outer case in the first direction; moving the first case body and the second case body relatively so that the second current collecting portion contacts the second case body of the outer case in the first direction; and fixing one of the first case body and the second case body relative to the other.

[0025] With this configuration, a battery cell with high volumetric efficiency can be manufactured.

[0026] Preferably, the first case body has a first base to which at least a portion of the first current collector is connected, and a first sidewall extending from the outer periphery of the first base in a first direction toward the electrode body. The second case body faces the first base and has a second base to which at least a portion of the second current collector is connected, and a second sidewall extending from the outer periphery of the second base in a second direction opposite to the first direction. The first sidewall and the second sidewall partially overlap when viewed from a second direction perpendicular to the first direction. The method for manufacturing a battery cell further includes the step of filling an insulating material between the first sidewall and the second sidewall.

[0027] With this configuration, the second case body and the first case body of the exterior case can be insulated from each other, thereby preventing a short circuit between the second case body and the first case body. [Effects of the Invention]

[0028] According to the present disclosure, it is possible to increase the volumetric efficiency of the battery cell. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is a diagram showing a battery cell. [Figure 2] FIG. 2 is a diagram showing a positive electrode current collecting portion and a negative electrode current collecting portion. [Figure 3] FIG. 2 is a diagram showing a battery module. [Figure 4] 10A to 10C are diagrams for explaining a manufacturing method of a battery cell. [Figure 5] 10A and 10B are diagrams for explaining a method for repairing a battery cell. [Figure 6] 10A and 10B are diagrams illustrating modified examples of the battery cell. [Figure 7] 10A and 10B are diagrams illustrating other modified examples of the battery cell. [Figure 8] FIG. 10 is a diagram illustrating yet another modified example of the battery cell. [Figure 9] FIG. 10 is a diagram illustrating yet another modified example of the battery cell. [Figure 10] FIG. 10 is a diagram illustrating yet another modified example of the battery cell. [Figure 11] FIG. 10 is a diagram illustrating yet another modified example of the battery cell. [Figure 12] 10A and 10B are diagrams showing a battery cell according to another embodiment. [Figure 13] 10A and 10B are diagrams showing a battery cell according to still another embodiment. [Figure 14] 10A and 10B are diagrams showing a battery cell according to still another embodiment. [Figure 15] 10A and 10B are diagrams showing a battery cell according to still another embodiment. [Figure 16] 10A and 10B are diagrams showing a battery cell according to still another embodiment. [Figure 17] FIG. 2 is a diagram showing an electrode unit. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0031] The various battery cells described below and battery modules equipped with these battery cells are installed in electric vehicles such as hybrid vehicles that can run using the power of at least one of a motor and an engine, and electric vehicles that run using driving force obtained from electrical energy.

[0032] In the following, terms such as upper, lower, top, and bottom are based on the orientation of the battery cell when it is manufactured. When the battery cell is installed in an electric vehicle, the orientation of the battery cell is not necessarily the same as the orientation at the time of manufacturing.

[0033] [Embodiment 1] (1. Battery cell) Fig. 1 is a diagram showing a battery cell according to the present embodiment. As shown in Fig. 1, the battery cell 1 includes an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4, a negative electrode current collector 5, an insulating material 6, and an insulating sheet 9. For ease of explanation, Fig. 1 shows cross sections of the outer case 2 and the insulating material 6.

[0034] The exterior case 2 houses the laminated electrode assembly 3, the positive electrode current collector 4, and the negative electrode current collector 5. The exterior case 2 includes a main body 2a and a lid 2b. The main body 2a has a bottom 21 and a sidewall 22 extending upward from the outer periphery of the bottom 21. The lid 2b has a top 25 facing the bottom 21 and a sidewall 26 extending downward from the outer periphery of the top 25.

[0035] Either the main body 2a or the lid 2b corresponds to the "first case body" of the present disclosure, and the other corresponds to the "second case body." Either the bottom 21 or the top 25 corresponds to the "first base" of the present disclosure, and the other corresponds to the "second base."

[0036] The lid 2b is placed over the main body 2a so as to cover a portion of the side wall 22 of the main body 2a. The side wall 22 and the side wall 26 partially overlap when viewed from the D2 direction perpendicular to the D1 direction, which is the stacking direction of the laminated electrode body 3.

[0037] The outer case 2 typically has a substantially rectangular parallelepiped shape. However, the shape of the outer case 2 is not limited to this. In this example, an electrolyte is sealed inside the outer case 2. The inside of the outer case 2 is a vacuum.

[0038] The bottom 21 of the main body 2a has an inner wall surface 211 and an outer wall surface 212. The side wall 22 of the main body 2a has an inner wall surface 221 and an outer wall surface 222. The inner wall surface 211 and the inner wall surface 221 are wall surfaces on the laminated electrode body 3 side.

[0039] The top portion 25 of the lid portion 2b has an inner wall surface 251 and an outer wall surface 252. The side wall portion 26 of the lid portion 2b has an inner wall surface 261 and an outer wall surface 262. The inner wall surface 251 and the inner wall surface 261 are wall surfaces on the laminated electrode body 3 side. The inner wall surface 251 faces the inner wall surface 211 of the bottom portion 21.

[0040] There is a gap between the side wall 22 of the main body 2a and the side wall 26 of the lid 2b. Specifically, there is a gap between the outer wall surface 222 of the side wall 22 and the inner wall surface 261 of the side wall 26. More specifically, a portion of the outer wall surface 222 of the main body 2a faces a portion of the inner wall surface 261 of the lid 2b.

[0041] The insulating material 6 is filled between the side wall portion 22 and the side wall portion 26. The insulating material 6 is filled between the outer wall surface 222 and the inner wall surface 261. The insulating material 6 is filled in the region (gap) where the outer wall surface 222 and the inner wall surface 261 face each other. The insulating material 6 insulates the main body portion 2a and the lid portion 2b from each other. The insulating material 6 fixes the lid portion 2b to the main body portion 2a. The insulating material 6 restricts movement of the lid portion 2b relative to the main body portion 2a in the direction D1. Furthermore, the insulating material 6 restricts movement of the lid portion 2b relative to the main body portion 2a in the direction D2 and in a direction perpendicular to the directions D1 and D2 (see the direction D3 in Figure 6).

[0042] In this example, the insulating material 6 is a thermoplastic resin. However, the insulating material 6 is not limited to this and may be an adhesive, a thermosetting resin, or a highly viscous fluid. The insulating material 6 may contain insulating particles. By including insulating particles, contact between the main body 2a and the lid 2b can be more reliably prevented.

[0043] The lid portion 2b is provided with a gas vent valve 7. More specifically, the valve 7 is provided on the side wall portion 26. The valve 7 allows gas generated by the stacked electrode body 3 to be discharged from inside the exterior case 2 to the outside.

[0044] The laminated electrode body 3 includes a plurality of positive electrodes 31, a plurality of negative electrodes 32, and a plurality of separators 33. In the laminated electrode body 3, two electrodes (positive electrodes 31 and negative electrodes 32) having different polarities are alternately stacked in the D1 direction with the separators 33 interposed between them. A restraining force (pressure) is applied to the laminated electrode body 3 in the D1 direction by the lid portion 2b and the main body portion 2a. More specifically, a restraining force is applied to the laminated electrode body 3 in the D1 direction by the top portion 25 and the bottom portion 21.

[0045] In this example, the end of the laminated electrode body 3 on the top 25 side is a positive electrode 31. The end of the laminated electrode body 3 on the bottom 21 side is also a positive electrode 31. The insulating sheet 9 is laminated on the end (positive electrode 31) on the bottom 21 side. Hereinafter, the positive electrode 31 on the end on the top 25 side will also be referred to as the "top-side positive electrode 31." The positive electrode 31 on the end on the bottom 21 side will also be referred to as the "bottom-side positive electrode 31."

[0046] Each positive electrode 31 includes a current collector foil 311 and active materials 312 and 313 coated on both sides of the current collector foil 311. The active material 312 is closer to the top portion 25 than the active material 313.

[0047] Each negative electrode 32 includes a current collector foil 321 and active materials 322 and 323 coated on both sides of the current collector foil 321. The active material 322 is closer to the top portion 25 than the active material 323.

[0048] Each separator 33 is sandwiched between a positive electrode 31 and a negative electrode 32. Each separator 33 is in contact with an active material 313 (or active material 312) and an active material 322 (or active material 323). Each separator 33 is permeated with an electrolyte solution.

[0049] The positive electrodes 31, the negative electrodes 32, the separators 33, and the insulating sheet 9 extend in the D2 direction and the D3 direction (see FIG. 6).

[0050] (2. Positive electrode current collector and negative electrode current collector) 2 is a diagram showing the positive electrode current collector 4 and the negative electrode current collector 5. Hereinafter, the positive electrode current collector 4 and the negative electrode current collector 5 will be described with reference to FIGS.

[0051] The positive electrode current collector 4 includes multiple current collector foils 41, each connected to a different positive electrode 31. In this example, the positive electrode current collector 4 includes five current collector foils 41. Each current collector foil 41 has a portion 411 extending in a direction from the positive electrode 31 toward the top portion 25, and a portion 412 that is continuous with the portion 411 and extends parallel to the top portion 25 between the top portion 25 and the laminated electrode body 3. Therefore, the positive electrode current collector 4 has five portions 411 and five portions 412.

[0052] The portions 412 of each current collector foil 41 are stacked in the direction D1 in a foil-like state. In this example, the portions 412 of the five current collector foils 41 are stacked in the direction D1 in a state where they are in close contact with each other. The portions 412 may or may not be welded to each other. The length of the portions 411 of the current collector foils 41 varies from one current collector foil 41 to another. On the other hand, the length of the portions 412 is the same for all current collector foils 41 in this example.

[0053] Each portion 412 is located between the lid portion 2b and the laminated electrode body 3 in the D1 direction. Each portion 412 is electrically connected to the lid portion 2b. The portion 412 of each current collecting foil 41 is connected to the top portion 25 of the lid portion 2b. More specifically, when pressure is applied in the D1 direction, one portion 412 contacts the inner wall surface 251 of the top portion 25. Each portion 412 faces the top-side positive electrode 31 in the D1 direction. The portion 412 is not insulated from the top-side positive electrode 31 of the laminated electrode body 3 and is overlapped on the top-side positive electrode 31. In this way, each portion 412 is electrically connected to the lid portion 2b and faces the top-side positive electrode 31 of the laminated electrode body 3 in the D1 direction.

[0054] In this example, the current collector foil 41 and the current collector foil 311 ( FIG. 1 ) of the positive electrode 31 are an integrated foil. That is, the current collector foil 41 and the current collector foil 311 are formed from a single piece of foil. In this example, the area not coated with the active materials 312, 313 corresponds to the current collector foil 41, and the area coated with the active materials 312, 313 corresponds to the current collector foil 311. The current collector foil 41 functions as a tab for the positive electrode 31. However, this is not a limitation, and the current collector foil 41 and the current collector foil 311 may be separate bodies. When the current collector foil 41 and the current collector foil 311 are separate bodies, a tab portion (uncoated area) may be provided on the current collector foil 311 in order to weld the current collector foil 41 to the current collector foil 311.

[0055] The negative electrode current collector 5 includes multiple current collector foils 51, each connected to a different negative electrode 32. In this example, the negative electrode current collector 5 includes four current collector foils 51. Each current collector foil 51 has a portion 511 extending in a direction from the negative electrode 32 toward the bottom 21, and a portion 512 that is continuous with portion 511 and extends parallel to the bottom 21 between the bottom 21 and the laminated electrode body 3. Therefore, the negative electrode current collector 5 has four portions 511 and four portions 512.

[0056] The portions 512 of the current collector foils 51 are stacked in the direction D1 in a foil-like state. In this example, the portions 512 of the four current collector foils 51 are stacked in the direction D1 in a state where they are in close contact with each other. The portions 512 may or may not be welded to each other. The length of the portions 511 of the current collector foils 51 varies from one current collector foil 51 to another. On the other hand, the length of the portions 512 is the same for all current collector foils 51 in this example.

[0057] Each portion 512 is located between the main body 2a and the laminated electrode body 3 in the D1 direction. Each portion 512 is electrically connected to the main body 2a. The portion 512 of each current collecting foil 51 is connected to the bottom 21 of the main body 2a. More specifically, when pressure is applied in the D1 direction, one portion 512 contacts the inner wall surface 211 of the bottom 21. Each portion 512 faces the bottom-side positive electrode 31 in the D1 direction. The portion 512 is overlapped on the bottom-side positive electrode 31 of the laminated electrode body 3 while being insulated from the bottom-side positive electrode 31.

[0058] In this way, each portion 512 is electrically connected to the main body 2a and faces the bottom-side positive electrode 31 of the laminated electrode body 3 in the D1 direction. The portion 512 and the bottom-side positive electrode 31 facing the portion 512 in the D1 direction are insulated from each other. The portion 512 and the bottom-side positive electrode 31 are insulated from each other by the insulating sheet 9.

[0059] In this example, the current collector foil 51 and the current collector foil 321 ( FIG. 1 ) of the negative electrode 32 are an integrated foil. That is, the current collector foil 51 and the current collector foil 321 are formed from a single piece of foil. In this example, the area not coated with the active materials 322, 323 corresponds to the current collector foil 51, and the area coated with the active materials 322, 323 corresponds to the current collector foil 321. The current collector foil 51 functions as a tab for the negative electrode 32. However, this is not a limitation, and the current collector foil 51 and the current collector foil 321 may be separate bodies. When the current collector foil 51 and the current collector foil 321 are separate bodies, a tab portion (uncoated area) may be provided on the current collector foil 321 in order to weld the current collector foil 51 to the current collector foil 321.

[0060] As shown in Figure 1, the lid portion 2b of the exterior case 2 is connected to the positive electrode current collector 4. The body portion 2a of the exterior case 2 is connected to the negative electrode current collector 5. The lid portion 2b and the body portion 2a are insulated from each other by an insulating material 6. Therefore, according to the battery cell 1, the lid portion 2b can function as a positive electrode terminal, and the body portion 2a can function as a negative electrode terminal.

[0061] (3. Summary of battery cells) (1) A battery cell 1 includes: (i) a laminated electrode assembly 3 in which negative electrodes 32 and positive electrodes 31 are alternately stacked in the D1 direction; (ii) a negative electrode current collector 5 connected to the plurality of negative electrodes 32; (iii) a positive electrode current collector 4 connected to the plurality of positive electrodes 31; and (iv) an exterior case 2 that houses the laminated electrode assembly 3, the negative electrode current collector 5, and the positive electrode current collector 4. The exterior case 2 includes a main body portion 2a and a lid portion 2b. A portion 512 of the negative electrode current collector 5 is located between the main body portion 2a and the laminated electrode assembly 3 in the D1 direction and is electrically connected to the main body portion 2a. A portion 412 of the positive electrode current collector 4 is located between the lid portion 2b and the laminated electrode assembly 3 in the D1 direction and is electrically connected to the lid portion 2b.

[0062] With this configuration, the negative electrode current collector 5 allows the main body 2a of the outer case 2 to function as a negative electrode terminal, and the positive electrode current collector 4 allows the lid 2b of the outer case 2 to function as a positive electrode terminal.

[0063] Furthermore, the negative electrode current collector 5 is connected to the main body 2a at a portion 512 located between the main body 2a and the laminated electrode assembly 3 in the D1 direction. The positive electrode current collector 4 is connected to the lid 2b at a portion 412 located between the lid 2b and the laminated electrode assembly 3 in the D1 direction. Therefore, the positive electrode current collector 4 and the negative electrode current collector 5 can each be in contact with the exterior case 2 at positions spaced apart from each other in the D1 direction.

[0064] Therefore, the battery cell 1 can achieve higher volumetric efficiency than a battery cell configuration in which only one of the negative electrode current collector and the positive electrode current collector is in contact with the exterior case.

[0065] (2) The main body 2a has a bottom 21 to which the portion 512 of the negative electrode current collector 5 is connected, and a sidewall 22 extending upward from the outer periphery of the bottom 21. The lid 2b faces the bottom 21 and has a top 25 to which the portion 412 of the positive electrode current collector 4 is connected, and a sidewall 26 extending downward from the outer periphery of the top 25. The sidewall 22 and the sidewall 26 partially overlap when viewed from the direction D2 perpendicular to the direction D1. With this configuration, the laminated electrode body 3, the positive electrode current collector 4, the negative electrode current collector 5, and the insulating material 6 can be reliably sealed within the exterior case 2.

[0066] (3) The insulating material 6 is filled between the side wall portion 22 and the side wall portion 26. With this configuration, it is possible to prevent a short circuit between the main body portion 2a and the lid portion 2b of the exterior case 2.

[0067] (4) The negative electrode current collector 5 includes multiple current collector foils 51, each connected to a different negative electrode 32. Each current collector foil 51 has a portion 511 extending from the negative electrode 32 toward the bottom 21 and a portion 512 that is continuous with the portion 511 and extends parallel to the bottom 21 between the bottom 21 and the laminated electrode body 3. The portion 512 is electrically connected to the main body 2a and faces the positive electrode 31 in the D1 direction. The portion 512 is insulated from the positive electrode 31 facing the portion 512 in the D1 direction (i.e., the bottom-side positive electrode 31). This configuration can prevent a short circuit between the negative electrode current collector 5 and the positive electrode 31 that faces the portion 512 of the negative electrode current collector 5 in the D1 direction.

[0068] (5) The positive electrode current collector 4 includes a plurality of current collector foils 41, each connected to a different positive electrode 31. Each current collector foil 41 has a portion 411 extending from the positive electrode 31 toward the top portion 25, and a portion 412 that is continuous with the portion 411 and extends parallel to the top portion 25 between the top portion 25 and the laminated electrode body 3. The portion 412 is electrically connected to the lid portion 2b.

[0069] (4. Battery module) Fig. 3 is a diagram showing a battery module. As shown in Fig. 3, a battery module 800 includes a plurality of battery cells 1, a positive electrode external terminal 810, a negative electrode external terminal 820, and an exhaust duct 830. In the battery module 800, the plurality of battery cells 1 are connected in series. In this example, four battery cells 1 are stacked in the D1 direction.

[0070] For ease of explanation, the battery cell 1 on the positive external terminal 810 side will also be referred to as the "first battery cell 1." The battery cell 1 on the negative external terminal 820 side will also be referred to as the "fourth battery cell 1." The battery cell 1 adjacent to the first battery cell 1 will also be referred to as the "second battery cell 1." The battery cell 1 adjacent to the fourth battery cell 1 will also be referred to as the "third battery cell 1."

[0071] The first battery cell 1 is in contact with the positive external terminal 810. More specifically, the lid portion 2b of the first battery cell 1 is in contact with the positive external terminal 810. More specifically, the top portion 25 of the lid portion 2b is in contact with the positive external terminal 810. The body portion 2a of the first battery cell 1 is in contact with the lid portion 2b of the second battery cell 1. More specifically, the bottom portion 21 of the body portion 2a is in contact with the top portion 25 of the lid portion 2b.

[0072] Similarly, the bottom 21 of the body 2a of the second battery cell 1 is in contact with the top 25 of the lid 2b of the third battery cell 1. The bottom 21 of the body 2a of the third battery cell 1 is in contact with the top 25 of the lid 2b of the fourth battery cell 1.

[0073] The fourth battery cell 1 is in contact with the negative external terminal 820. More specifically, the main body 2a of the fourth battery cell 1 is in contact with the negative external terminal 820. More specifically, the bottom 21 of the main body 2a is in contact with the negative external terminal 820.

[0074] In this way, the battery module 800 can be manufactured by stacking and connecting the battery cells 1 so that the body 2a of one battery cell 1 contacts the lid 2b of another battery cell 1. Therefore, the battery module 800 with high volumetric efficiency can be easily manufactured.

[0075] Exhaust duct 830 is connected to valves 7 provided on sidewall 26 of lid 2b of outer case 2. Exhaust duct 830 covers each valve 7. A portion of exhaust duct 830 is in contact with sidewall 26 of lid 2b of each outer case 2.

[0076] Each valve 7 and exhaust duct 830 allows gas generated by each stacked electrode body 3 to be discharged from inside the exterior case 2 to the outside. By treating the discharged gas in a downstream device, it is possible to prevent the gas from leaking outside without being treated.

[0077] (5. Battery Cell Manufacturing Method) 4 is a diagram illustrating a method for manufacturing the battery cell 1. As shown in FIG. 4, the press machine 900 includes a slide 910 and a bolster 920 provided directly below the slide 910.

[0078] The battery cell 1 having the insulating material 6 before solidification is placed on the bolster 920. The battery cell 1 is placed on the bolster 920 so that the stacking direction (D1) of the laminated electrode body 3 is vertical. The battery cell 1 is placed on the bolster 920 so that the bottom 21 of the main body 2a of the exterior case 2 contacts the bolster 920.

[0079] The press machine 900 applies a compressive force to the battery cell 1 in the directions of arrows A1 and A2 in the direction D1 to compress the battery cell 1. Specifically, the slide 910 is lowered to apply a force in the direction D1 to the battery cell 1. This applies a force in the direction D1 to the laminated electrode body 3. In this state, the insulating material 6 is solidified. The solidification of the insulating material 6 fixes the lid portion 2b to the main body portion 2a. Therefore, even when the slide 910 is raised, the lid portion 2b and the main body portion 2a can continue to apply a force (restraining force) in the direction D1 to the laminated electrode body 3. In other words, a surface pressure can be applied to the laminated electrode body 3.

[0080] In detail, before the insulating material 6 is solidified, the slide 910 and the bolster 920 apply a force in the D1 direction to the battery cell 1, thereby preventing the weight in the D1 direction from concentrating on the side wall portion 26 of the lid portion 2b and the side wall portion 22 of the main body portion 2a.

[0081] The method for manufacturing the battery cell 1 includes the steps of: placing the battery cell 1, which includes a laminated electrode assembly 3 in which negative electrodes 32 and positive electrodes 31 are alternately stacked in the D1 direction, a negative electrode current collector 5 connected to the plurality of negative electrodes 32, and a positive electrode current collector 4 connected to the plurality of positive electrodes 31, using a conveying machine (not shown) so that the negative electrode current collector 5 contacts the main body 2a of the outer case 2 in the D1 direction; and moving the lid portion 2b of the outer case 2 using the conveying machine so that the positive electrode current collector 4 contacts the lid portion 2b in the D1 direction. In this example, the lid portion 2b is placed over the main body 2a by this movement. The method further includes the step of fixing the lid portion 2b to the main body 2a. This method can improve the manufacturing efficiency of the battery cell 1.

[0082] In this example, the lid portion 2b is fixed to the main body portion 2a in a state where the outer case 2 is compressed in the D1 direction by the press machine 900 and the lid portion 2b and the main body portion 2a are insulated from each other. However, depending on the constituent materials of the battery, the above-described fixing can be performed even without the insulating state. The process of fixing the lid portion 2b to the main body portion 2a is typically performed by a machine (not shown).

[0083] In the above, the lid portion 2b is moved to cover the main body portion 2a. However, this is not limiting. Instead of moving the lid portion 2b, the main body portion 2a may be moved. Alternatively, the lid portion 2b and the main body portion 2a may be moved. It is sufficient to move the main body portion 2a and the lid portion 2b relative to each other.

[0084] The manufacturing method further includes a step of filling the gap between the side wall portion 22 and the side wall portion 26 with an insulating material 6. This method can insulate the lid portion 2b from the main body portion 2a, thereby preventing a short circuit between the lid portion 2b and the main body portion 2a.

[0085] (6. Battery cell repair method) FIG. 5 is a diagram illustrating a method for repairing a battery cell 1. As the battery cell 1 is used, the laminated electrode body 3 may become thinner. Specifically, as the battery cell 1 is used, the thickness of the laminated electrode body 3 in the D1 direction decreases compared to the initial state shown in state (A) of FIG. 5. In this state, the force (constraining force, surface pressure) applied to the laminated electrode body 3 in the D1 direction disappears, as shown in state (B). Note that state (B) shows a state in which a gap has formed between portion 412 of the positive electrode current collector 4 and the top portion 25 of the exterior case 2.

[0086] In such cases, the following procedure is performed using the heat press 900A. The battery cell 1 is placed on the bolster 920 of the heat press 900A. Next, as shown in state (C), the slide of the heat press 900A is lowered to the position of the top part 25 of the lid part 2b. In this state, heat is applied to the battery cell 1. Specifically, heat is applied to the exterior case 2 from at least one of the slide 910 and the bolster 920. The heat transferred to the exterior case 2 is also transferred to the insulating material 6. As a result, the solidified (hardened) insulating material 6 softens.

[0087] With the insulating material 6 softened, the slide 910 is further lowered as shown in state (D). Specifically, the slide 910 is moved in the direction of arrow B. This applies a force in the direction D1 to the laminated electrode assembly 3. In this state, the application of heat is stopped, and the insulating material 6 is solidified. The re-solidification of the insulating material 6 fixes the lid portion 2b to the main body portion 2a. Therefore, even when the slide 910 is raised, the lid portion 2b and the main body portion 2a can continue to apply a force in the direction D1 to the laminated electrode assembly 3. In this way, by using the heat press machine 900A to reduce the thickness of the exterior case 2 in the direction D1, it is possible to apply surface pressure to the laminated electrode assembly 3 again. This allows the performance of the battery cell 1 to be restored.

[0088] <Modification> Below, we will explain several modified examples of the battery cell 1. As with the battery cell 1, these modified examples also enable increased volumetric efficiency compared to a battery cell configuration in which only one of the negative electrode current collector and the positive electrode current collector is in contact with the exterior case.

[0089] (First Modification) 1 and 2, etc., has been described as an example of a configuration in which the positive electrode current collector 4 is connected to the lid 2b of the exterior case 2 and the negative electrode current collector 5 is connected to the body 2a of the exterior case 2, but this is not limiting. The positive electrode current collector 4 may be connected to the body 2a of the exterior case 2 and the negative electrode current collector 5 may be connected to the lid 2b of the exterior case 2. In this case, the body 2a side becomes the positive electrode of the battery cell 1, and the lid 2b side becomes the negative electrode of the battery cell 1.

[0090] (Second Modification) In the laminated electrode body 3, the electrodes at both ends of the laminate are positive electrodes 31, but the present invention is not limited to this. The laminated electrode body 3 may also be configured so that the electrodes at both ends of the laminate are negative electrodes 32.

[0091] Alternatively, the laminated electrode body 3 may be configured so that the electrode at the end on the main body 2a side is the positive electrode 31 and the electrode at the end on the lid 2b side is the negative electrode 32. In this configuration, the portion 412 is electrically connected to the lid 2b and faces the negative electrode 32 in the D1 direction. Therefore, the portion 412 and the negative electrode 32 facing the portion 412 in the D1 direction are insulated from each other by an insulating sheet (not shown). This configuration can prevent a short circuit between the positive electrode current collector 4 and the negative electrode 32 that faces the portion 412 of the positive electrode current collector 4 in the D1 direction.

[0092] The laminated electrode body 3 may be configured such that the electrode at the end on the main body 2a side is the negative electrode 32 and the electrode at the end on the lid 2b side is the positive electrode 31. Even in this configuration, short circuits can be prevented by appropriately arranging an insulating sheet.

[0093] (Third Modification) FIG. 6 is a diagram illustrating a third modified example of the battery cell 1. For ease of explanation, the lid portion 2b of the exterior case 2 is omitted from FIG. 6. As shown in FIG. 6, the battery cell 1A further includes a spacer 101 in addition to the exterior case 2, the laminated electrode assembly 3, the positive electrode current collector 4, the negative electrode current collector 5, and the insulating material 6. The battery cell 1A differs from the battery cell 1 in that it includes the spacer 101.

[0094] The spacer 101 is an insulating member. The spacer 101 is disposed between the laminated electrode assembly 3 and the main body 2a of the exterior case 2. More specifically, the spacer 101 is provided inside the main body 2a so as to fit along the inner wall surface 221 (see FIG. 1 ) of the side wall 22 of the main body 2a. The spacer 101 covers the periphery of the laminated electrode assembly 3. In this example, the spacer 101 is in contact with the current collector foil 41 and the current collector foil 51. More specifically, the spacer 101 is in contact with a portion 411 of the current collector foil 41 and a portion 511 of the current collector foil 51.

[0095] According to this configuration, the spacer 101 can prevent the laminated electrode body 3 from becoming misaligned within the exterior case 2. More specifically, the laminated electrode body 3 can be prevented from moving in the directions D2 and D3 within the exterior case 2.

[0096] (Fourth Modification) Fig. 7 is a diagram illustrating a fourth modified example of the battery cell 1. As shown in Fig. 7, the battery cell 1B further includes a positioning frame 102 in addition to an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4, a negative electrode current collector 5, and an insulating material 6. The battery cell 1A differs from the battery cell 1 in that it includes the frame 102. Note that Fig. 7 shows a cross section of part of the frame 102.

[0097] The frame body 102 rises in the direction D1 from the side wall 26 of the lid 2b. More specifically, the frame body 102 rises from the outer wall surface 262 of the side wall 26 (see FIG. 1) in the direction opposite to the direction toward the main body 2a. The frame body 102 protrudes in the direction D1 from the top 25. When the exterior case 2 is viewed from the lid 2b side in the direction D1, the frame body 102 has a rectangular frame shape with an opening formed along the side wall 26.

[0098] With this configuration, when a plurality of battery cells 1B are stacked, it is possible to prevent the battery cells 1B from becoming misaligned with one another.

[0099] (Fifth Modification) Fig. 8 is a diagram illustrating a fifth modified example of the battery cell 1. As shown in Fig. 8, the battery cell 1C, like the battery cell 1, includes an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4, a negative electrode current collector 5, and an insulating material 6. In the battery cell 1C, the main body 2a and lid 2b of the outer case 2 are coated with a highly electrically conductive material.

[0100] Specifically, inner wall surface 211 of bottom portion 21 of main body portion 2a is covered with highly conductive metal layer 103. Outer wall surface 212 of bottom portion 21 is covered with highly conductive metal layer 104. Similarly, inner wall surface 251 of top portion 25 is covered with highly conductive metal layer 105. Outer wall surface 252 of top portion 25 is covered with highly conductive metal layer 106. For example, metal layers 103 to 106 may be formed from the same metal.

[0101] With this configuration, when the battery cells 1C are stacked to form a battery module as shown in FIG. 3, the electrical resistance between adjacent battery cells 1C can be reduced compared to a configuration in which the outer case 2 is not covered.

[0102] (Sixth Modification) FIG. 9 is a diagram illustrating a sixth modified example of the battery cell 1. As shown in FIG. 9, the battery cell 1D includes an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4, and a negative electrode current collector 5. Unlike the battery cell 1, the battery cell 1D does not include an insulating material 6. However, like the battery cell 1, the battery cell 1D also needs to insulate the main body 2a and lid 2b of the outer case 2. For this reason, the battery cell 1D has the following configuration.

[0103] In the battery cell 1D, the side wall 22 of the main body 2a and the side wall 26 of the lid 2b of the exterior case 2 are pre-insulated. Specifically, the outer wall surface 222 of the side wall 22 is covered with an insulating member 107. The inner wall surface 261 of the side wall 26 is covered with an insulating member 108.

[0104] With this configuration, there is no contact between the outer wall surface 222 of the side wall portion 22 and the inner wall surface 261 of the side wall portion 26. This prevents a short circuit between the main body portion 2a and the lid portion 2b.

[0105] In particular, when viewed from the D2 direction, the insulating material overlaps where the main body 2a and the lid 2b overlap, which can further prevent short circuits between the main body 2a and the lid 2b compared to a configuration where the insulating material does not overlap.

[0106] (Seventh Modification) Fig. 10 is a diagram illustrating a seventh modified example of the battery cell 1. As shown in Fig. 10, the battery cell 1E includes an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4, and a negative electrode current collector 5. Like the battery cell 1D, the battery cell 1E does not include an insulating material 6.

[0107] In the battery cell 1E, the side wall 22 of the main body 2a and the side wall 26 of the lid 2b of the exterior case 2 are insulated in advance. Specifically, the inner wall surface 221 of the side wall 22 is covered with an insulating member 109. The inner wall surface 261 of the side wall 26 is covered with an insulating member 110.

[0108] With this configuration, member 110 prevents contact between main body 2a and lid 2b of exterior case 2. Therefore, it is possible to prevent a short circuit between main body 2a and lid 2b. Furthermore, member 109 prevents contact between exterior case 2 and laminated electrode body 3. More specifically, it is possible to prevent contact between side wall 22 of exterior case 2 and laminated electrode body 3. Therefore, it is possible to prevent a short circuit between main body 2a and laminated electrode body 3.

[0109] As with the battery cell 1D described above, the outer wall surface 222 of the side wall portion 22 of the main body portion 2a may also be insulated in advance. That is, the inner wall surface 221 and the outer wall surface 222 of the side wall portion 22 may be insulated in advance. Furthermore, the outer wall surface 262 of the side wall portion of the lid portion 2b may also be insulated in advance. That is, the inner wall surface 261 and the outer wall surface 262 of the side wall portion 26 may be insulated in advance.

[0110] The above is not limitative, and it is sufficient that at least one of the outer wall surface 222 of the side wall portion 22 and the inner wall surface 261 of the side wall portion 26 is insulated. As in the battery cell 1D, it is preferable that both the outer wall surface 222 of the side wall portion 22 and the inner wall surface 261 of the side wall portion 26 are insulated.

[0111] It is preferable to perform an insulating process on the outer wall surfaces 222, 262. With this configuration, it is possible to prevent short circuits between the battery cell 1 and objects external to the battery cell 1.

[0112] (Eighth Modification) Fig. 11 is a diagram illustrating an eighth modified example of the battery cell 1. As shown in Fig. 11, the battery cell 1F includes an outer case 2, a laminated electrode assembly 3, a positive electrode current collector 4A, a negative electrode current collector 5A, and an insulating material 6. The battery cell 1F differs from the battery cell 1 that includes a positive electrode current collector 4 and a negative electrode current collector 5 in that it includes a positive electrode current collector 4A and a negative electrode current collector 5A.

[0113] The positive electrode current collecting part 4A includes a plurality of current collecting foils 41A and an L-shaped positive electrode plate 450. The positive electrode plate 450 has a portion 451 extending in the D1 direction and a portion 452 that is continuous with the portion 451 and extends parallel to the top portion 25 between the top portion 25 and the laminated electrode body 3.

[0114] The portion 451 has an inner surface 4511 on the laminated electrode body 3 side and an outer surface 4512 opposite the inner surface 4511. The portion 452 has an inner surface 4521 on the laminated electrode body 3 side and an outer surface 4522 opposite the inner surface 4521. The inner surface 4521 is in contact with the top-side positive electrode 31. The outer surface 4522 is in contact with the top portion 25 of the exterior case 2. More specifically, the outer surface 4522 is in contact with the inner wall surface 251 of the top portion 25.

[0115] In this example, current collector foil 41A and current collector foil 311 of positive electrode 31 are an integrated foil. Each current collector foil 41A is welded to a portion 451 of positive electrode plate 450 in a collected state. More specifically, each current collector foil 41A is welded to an inner surface 4511 of portion 451.

[0116] The negative electrode current collector 5A includes a plurality of current collector foils 51A and an L-shaped negative electrode plate 550. The negative electrode plate 550 has a portion 551 extending in the D1 direction and a portion 552 that is continuous with the portion 551 and extends parallel to the bottom portion 21 between the bottom portion 21 and the laminated electrode body 3.

[0117] The portion 551 has an inner surface 5511 facing the laminated electrode body 3 and an outer surface 5512 opposite the inner surface 5511. The portion 552 has an inner surface 5521 facing the laminated electrode body 3 and an outer surface 5512 opposite the inner surface 5521. The inner surface 5521 is in contact with the insulating sheet 9. The outer surface 5512 is in contact with the bottom 21 of the exterior case 2. More specifically, the outer surface 5512 is in contact with the inner wall surface 211 of the bottom 21.

[0118] In this example, current collector foil 51A and current collector foil 321 of negative electrode 32 are integrated into one foil. Each current collector foil 51A is welded to portion 551 of negative electrode plate 550 in a collected state. More specifically, each current collector foil 51A is welded to an inner surface 5511 of portion 551.

[0119] According to the above configuration, for example, by making the thickness of the positive electrode plate 450 and the negative electrode plate 550 thinner than the thickness of a plurality of current collector foils 41A stacked together, it is possible to make the battery smaller than the battery cell 1.

[0120] Furthermore, with the above configuration, for example, by making the thickness of positive electrode plate 450 and negative electrode plate 550 greater than the thickness of multiple current collector foils 41A stacked together, the resistance between positive electrode current collector 4A and negative electrode current collector 5A can be made smaller than the resistance between positive electrode current collector 4 and negative electrode current collector 5 in battery cell 1. This reduces the variation in current between the surface of negative electrode current collector 5A that contacts bottom portion 21 and the surface of positive electrode current collector 4A that contacts top portion 25. As a result, the temperature distribution in portions 452 and 552 can be made uniform.

[0121] Furthermore, with the above configuration, for example, by forming the positive electrode current collector 4A and the negative electrode current collector 5A using a metal with higher electrical conductivity than that of the current collector foils 41A and 51A, the resistance between the positive electrode current collector 4A and the negative electrode current collector 5A can be made smaller than the resistance between the positive electrode current collector 4 and the negative electrode current collector 5 in the battery cell 1. This reduces the variation in current between the surface of the negative electrode current collector 5A that contacts the bottom portion 21 and the surface of the positive electrode current collector 4A that contacts the top portion 25. As a result, the temperature distribution in the portions 452 and 552 can be made uniform.

[0122] It is preferable to insulate the surface of each current collector foil 41A. This configuration can prevent short-circuiting between current collector foil 41A and main body 2a of outer case 2. Similarly, it is preferable to insulate the surface of each current collector foil 51A. This configuration can prevent short-circuiting between current collector foil 51A and lid 2b of outer case 2.

[0123] [Embodiment 2] In the first embodiment, a configuration was described in which an electrolyte solution was poured into the exterior case 2 and the laminated electrode body 3 was provided with a separator 33. In the present embodiment, a case will be described in which the battery cell is an all-solid-state battery that does not require an electrolyte solution.

[0124] Fig. 12 is a diagram showing a battery cell 1G according to this embodiment. As shown in Fig. 12, the battery cell 1G includes an outer case 2, a laminated electrode body 3A, a positive electrode current collector 4, a negative electrode current collector 5, an insulating material 6, and an insulating sheet 9. The battery cell 1G differs from the battery cell 1 in that the battery cell 1G includes a laminated electrode body 3A instead of the laminated electrode body 3. The following describes the configuration of the battery cell 1G, focusing on the differences from the battery cell 1.

[0125] The laminated electrode body 3A includes a plurality of positive electrodes 31, a plurality of negative electrodes 32, and a plurality of separator layers 35. The laminated electrode body 3A differs from the laminated electrode body 3 in that it has a plurality of separator layers 35 instead of a plurality of separators 33. Each separator layer 35 includes a solid electrolyte and a binder.

[0126] In the laminated electrode body 3A, positive electrodes 31 and negative electrodes 32 are alternately stacked in the D1 direction with separator layers 35 interposed between them. That is, the laminated electrode body 3A has the separator layers 35 between the positive electrodes 31 and the negative electrodes 32. Note that, similar to the laminated electrode body 3, a restraining force (pressure) is applied to the laminated electrode body 3A in the D1 direction by the lid portion 2b and the main body portion 2a.

[0127] The battery cell 1G is easier to manufacture than the battery cell 1 because it does not require injection of an electrolyte into the exterior case 2. Furthermore, the battery cell 1G achieves the same effects as those achieved by the battery cell 1 according to embodiment 1. Furthermore, the various variations described in embodiment 1 can be applied to the battery cell 1G as appropriate.

[0128] [Embodiment 3] In the second embodiment, a configuration in which the battery cell 1G includes one laminated electrode body 3A has been described. In the present embodiment, a configuration in which the battery cell includes multiple laminated electrode bodies 3A will be described.

[0129] Fig. 13 is a diagram showing a battery cell 1H according to this embodiment. As shown in Fig. 13, the battery cell 1H includes an outer case 2A, three laminated electrode assemblies 3A, three positive electrode current collectors 4, three negative electrode current collectors 5, and an insulating material 6A. The three laminated electrode assemblies 3A are arranged side by side in the D1 direction. The three positive electrode current collectors 4 and the three negative electrode current collectors 5 are also arranged side by side in the D1 direction. The number of laminated electrode assemblies 3A, the number of positive electrode current collectors 4, and the number of negative electrode current collectors 5 are not limited to three, and may be two or more.

[0130] The exterior case 2A includes a main body 2c and a lid 2d. The main body 2c has a bottom 21A and a sidewall 22A extending upward from the outer periphery of the bottom 21A. The lid 2d has a top 25A facing the bottom 21A and a sidewall 26A extending downward from the outer periphery of the top 25A.

[0131] The lid 2d is placed over the main body 2c so as to cover a portion of the side wall 22A of the main body 2c. The side wall 22A and the side wall 26A partially overlap when viewed from the direction D2 perpendicular to the direction D1, which is the stacking direction of the stacked electrode bodies 3A.

[0132] The outer case 2A is typically in the shape of a substantially rectangular parallelepiped, similar to the outer case 2. However, the shape of the outer case 2A is not limited to this.

[0133] The bottom 21A of the main body 2c has an inner wall surface 211A and an outer wall surface 212A. The side wall 22A of the main body 2c has an inner wall surface 221A and an outer wall surface 222A. The inner wall surface 211A and the inner wall surface 221A are wall surfaces on the stacked electrode body 3A side.

[0134] Bottom portion 21A has the same function as bottom portion 21 in embodiment 1. Bottom portion 21A has the same shape as bottom portion 21. Side wall portion 22A has the same function as side wall portion 22 in embodiment 1. To accommodate multiple stacked electrode bodies 3A inside outer case 2A, the length of side wall portion 22A in the D1 direction is longer than the length of side wall portion 22 in the D1 direction.

[0135] The top portion 25A of the lid portion 2d has an inner wall surface 251A and an outer wall surface 252A. The side wall portion 26A of the lid portion 2d has an inner wall surface 261A and an outer wall surface 262A. The inner wall surface 251A and the inner wall surface 261A are wall surfaces on the stacked electrode body 3A side. The inner wall surface 251A faces the inner wall surface 211A of the bottom portion 21A.

[0136] Top portion 25A has the same function as top portion 25 in embodiment 1. Top portion 25A has the same shape as top portion 25. Side wall portion 26A has the same function as side wall portion 26 in embodiment 1. To accommodate multiple stacked electrode bodies 3A inside outer case 2A, the length of side wall portion 26A in the D1 direction is longer than the length of side wall portion 26 in the D1 direction.

[0137] There is a gap between the side wall 22A of the main body 2c and the side wall 26A of the lid 2d. Specifically, there is a gap between the outer wall surface 222A of the side wall 22A and the inner wall surface 261A of the side wall 26A. More specifically, a portion of the outer wall surface 222 of the main body 2a faces a portion of the inner wall surface 261 of the lid 2b.

[0138] The insulating material 6A is filled between the side wall portion 22 and the side wall portion 26. The insulating material 6A is filled between the outer wall surface 222A and the inner wall surface 261A. The insulating material 6A is filled in the region (gap) where the outer wall surface 222A and the inner wall surface 261A face each other. The insulating material 6A insulates the main body portion 2c and the lid portion 2d from each other. The insulating material 6A fixes the lid portion 2d to the main body portion 2c. The insulating material 6A restricts movement of the lid portion 2d relative to the main body portion 2c in the directions D1, D2, and D3.

[0139] The material of the insulating material 6A is the same as that of the insulating material 6 described in embodiment 1. In this example, the length of the insulating material 6A in the D1 direction is longer than the length of the insulating material 6 in the D1 direction. The lid 2d is provided with a gas vent valve 7, similar to the lid 2b in embodiment 1.

[0140] Hereinafter, for ease of explanation, the laminated electrode body 3A on the top 25 side will also be referred to as the "top-side laminated electrode body 3A." The laminated electrode body 3A on the bottom 21 side will also be referred to as the "bottom-side laminated electrode body 3A." The laminated electrode body 3A between the top-side laminated electrode body 3A and the bottom-side laminated electrode body 3A will also be referred to as the "intermediate laminated electrode body 3A."

[0141] Similarly, the positive electrode current collector 4 and negative electrode current collector 5 connected to the top-side laminated electrode body 3A are also referred to as the "top-side positive electrode current collector 4" and the "top-side negative electrode current collector 5," respectively. Similarly, the positive electrode current collector 4 and negative electrode current collector 5 connected to the intermediate laminated electrode body 3A are also referred to as the "intermediate positive electrode current collector 4" and the "intermediate negative electrode current collector 5," respectively. The positive electrode current collector 4 and negative electrode current collector 5 connected to the bottom-side laminated electrode body 3A are also referred to as the "bottom-side positive electrode current collector 4" and the "bottom-side negative electrode current collector 5," respectively.

[0142] In the battery cell 1G, a portion 412 of each current collecting foil 41 in the top-side positive current collecting portion 4 is connected to the top portion 25A of the lid portion 2d. A portion 512 of each current collecting foil 51 in the top-side negative current collecting portion 5 and a portion 412 of each current collecting foil 41 in the intermediate positive current collecting portion 4 are overlapped so as to come into contact in the direction D1. Similarly, a portion 512 of each current collecting foil 51 in the intermediate negative current collecting portion 5 and a portion 412 of each current collecting foil 41 in the bottom-side positive current collecting portion 4 are overlapped so as to come into contact in the direction D1. A portion 512 of each current collecting foil 51 in the bottom-side negative current collecting portion 5 is connected to the bottom portion 21A of the body portion 2c.

[0143] Because the laminated electrode body 3A has a separator layer 35 instead of a separator 33, it can be inspected for discharge and charge before being housed in the outer case 2A. Therefore, by housing only laminated electrode bodies 3A that have been determined to be non-defective in the outer case 2A, the quality of the battery cell 1H can be ensured. Furthermore, the battery cell 1G achieves the same effects as those achieved by the battery cell 1 according to the first embodiment. Furthermore, the various modifications described in the first embodiment can be applied to the battery cell 1G as appropriate.

[0144] The battery cell 1H includes multiple laminated electrode bodies 3A. Therefore, even if the number of positive electrodes 31 and negative electrodes 32 included in each laminated electrode body 3A is reduced compared to the laminated electrode body 3 included in the battery cell 1, the battery cell 1H can exhibit performance equivalent to or better than that of the battery cell 1. Furthermore, because the number of positive electrodes 31 and negative electrodes 32 in the laminated electrode body 3A can be reduced as described above, the defective rate of the laminated electrode body 3A can be reduced.

[0145] [Embodiment 4] In the first to third embodiments, the configuration in which the battery cells 1, 1A to 1H include the stacked electrode bodies 3, 3A has been described. In the present embodiment, the configuration in which the battery cells include a wound electrode body will be described.

[0146] 14 is a diagram showing a battery cell 1P according to the present embodiment. As shown in FIG. 14, the battery cell 1P includes an outer case 2, a wound electrode body 3B, a positive electrode current collector 4, and a negative electrode current collector 5.

[0147] Battery cell 1P differs from battery cells 1, 1A to 1H of embodiments 1 to 3 in that it includes a wound electrode body 3B instead of laminated electrode bodies 3, 3A. Battery cell 1P also differs from battery cells 1, 1A to 1H of embodiments 1 to 3 in that it does not include an insulating sheet 9.

[0148] The wound electrode body 3B has an insulating outer casing 37. The wound electrode body 3B has a winding axis extending in a D3 direction (see FIG. 6) perpendicular to the D1 and D2 directions, and is configured by spirally winding a laminate including a strip-shaped positive electrode, a strip-shaped negative electrode, and a strip-shaped separator around the winding axis. More specifically, the wound electrode body 3B accommodates the spirally wound laminate together with an electrolyte solution within the outer casing 37.

[0149] In wound electrode body 3B, positive electrodes and negative electrodes are alternately stacked from the winding axis toward the outer periphery. Therefore, in wound electrode body 3B, positive electrodes and negative electrodes are alternately stacked at least in direction D1.

[0150] In this example, four current collector foils 41 are connected to the strip-shaped positive electrode. Each current collector foil 41 functions as a positive electrode tab for the wound electrode body 3B. Similarly, four current collector foils 51 are connected to the strip-shaped negative electrode. Each current collector foil 51 functions as a negative electrode tab for the wound electrode body 3B.

[0151] The battery cell 1H having the above configuration has the same effects as those of the battery cell 1 according to embodiment 1. In addition, the various modifications described in embodiment 1 can be applied to the battery cell 1G as appropriate.

[0152] [Embodiment 5] In the first to third embodiments, the laminated electrode bodies 3, 3A are monopolar type electrode bodies, whereas in the present embodiment, the laminated electrode body is a bipolar type electrode body.

[0153] Fig. 15 is a diagram showing a battery cell 1Q according to the present embodiment. As shown in Fig. 15, the battery cell 1Q includes an outer case 2, a laminated electrode body 3C, a positive electrode current collector 4B, and a negative electrode current collector 5B. The battery cell 1Q differs from the battery cells 1, 1A-1H according to the first to third embodiments in that it includes a laminated electrode body 3C instead of the laminated electrode bodies 3, 3A.

[0154] Furthermore, battery cell 1Q differs from battery cells 1, 1A to 1H of embodiments 1 to 3 in that it includes a positive electrode current collector 4B and a negative electrode current collector 5B instead of positive electrode current collectors 4, 4A and negative electrode current collectors 5, 5B. Battery cell 1Q differs from battery cells 1, 1A to 1H of embodiments 1 to 3 in that it does not include insulating sheet 9.

[0155] A restraining force (pressure) is applied to the laminated electrode body 3C in the direction D1 by the lid portion 2b and the main body portion 2a, similar to the laminated electrode body 3. The exterior case 2 is filled with an electrolyte.

[0156] The laminated electrode body 3C is a bipolar type electrode body. The laminated electrode body 3C includes a plurality of bipolar electrodes 350 and a plurality of separators 360. In the laminated electrode body 3C, the plurality of bipolar electrodes 350 are stacked in the D1 direction with the separators 360 interposed therebetween.

[0157] Each bipolar electrode 350 has a current collecting foil 351, a positive electrode 352, and a negative electrode 353. The positive electrode 352 is formed on one side of the current collecting foil 351. The negative electrode 353 is formed on the other side of the current collecting foil 351. In this example, the positive electrode 352 is formed on the surface of the current collecting foil 351 facing the lid portion 2b. The positive electrode 352 is formed on the surface of the current collecting foil 351 facing the main body portion 2a.

[0158] The positive electrode current collector 4B and the negative electrode current collector 5B function as current collectors for the laminated electrode body 3C. Specifically, the positive electrode current collector 4B and the negative electrode current collector 5B function as terminal electrodes for the laminated electrode body 3C.

[0159] The positive electrode current collecting portion 4B is stacked on the bipolar electrode 350 on the top portion 25 side via a separator 360 in the D1 direction. Furthermore, the positive electrode current collecting portion 4B is in contact with the inner wall surface 251 of the top portion 25. The negative electrode current collecting portion 5B is stacked on the bipolar electrode 350 on the bottom portion 21 side via a separator 360 in the D1 direction. Furthermore, the negative electrode current collecting portion 5B is in contact with the inner wall surface 211 of the bottom portion 21.

[0160] More specifically, the positive electrode current collector 4B has a current collector foil 481 and a negative electrode 483. One surface of the current collector foil 481 is in contact with the inner wall surface 251 of the top portion 25. The negative electrode 483 is formed on the other surface of the current collector foil 481. The negative electrode 483 of the positive electrode current collector 4B and the positive electrode 352 of the bipolar electrode 350 adjacent to the positive electrode current collector 4B face each other with the separator 360 interposed therebetween.

[0161] The negative electrode current collector 5B has a current collector foil 581 and a positive electrode 582. One surface of the current collector foil 581 is in contact with the inner wall surface 211 of the bottom 21. The positive electrode 582 is formed on the other surface of the current collector foil 581. The positive electrode 582 of the negative electrode current collector 5B and the negative electrode 353 of the bipolar electrode 350 adjacent to the negative electrode current collector 5B face each other with the separator 360 interposed therebetween.

[0162] As described above, the battery cell 1Q includes (i) a laminated electrode assembly 3C in which negative electrodes 353 and positive electrodes 352 are alternately stacked in the D1 direction, (ii) a negative electrode current collector 5B connected to one negative electrode 353, (iii) a positive electrode current collector 4B connected to one positive electrode 352, and (iv) an exterior case 2 that houses the laminated electrode assembly 3C, the negative electrode current collector 5B, and the positive electrode current collector 4B. The exterior case 2 includes a main body 2a and a lid 2b. The current collector foil 581 of the negative electrode current collector 5 is located between the main body 2a and the laminated electrode assembly 3C in the D1 direction and is electrically connected to the main body 2a. The current collector foil 481 of the positive electrode current collector 4B is located between the lid 2b and the laminated electrode assembly 3C in the D1 direction and is electrically connected to the lid 2b.

[0163] With this configuration, the negative electrode current collecting portion 5B allows the main body 2a of the outer case 2 to function as a negative electrode terminal, and the positive electrode current collecting portion 4B allows the lid 2b of the outer case 2 to function as a positive electrode terminal.

[0164] Furthermore, the negative electrode current collector 5B is connected to the main body 2a by a current collector foil 581 located between the main body 2a and the laminated electrode body 3C in the D1 direction. The positive electrode current collector 4B is connected to the lid 2b by a current collector foil 481 located between the lid 2b and the laminated electrode body 3C in the D1 direction. Therefore, the positive electrode current collector 4B and the negative electrode current collector 5B can each be in contact with the exterior case 2 at positions spaced apart from each other in the D1 direction.

[0165] Therefore, the battery cell 1Q can improve volumetric efficiency compared to a battery cell configuration in which only one of the negative electrode current collector and the positive electrode current collector is in contact with the exterior case.

[0166] [Embodiment 6] In this embodiment, a battery cell having a laminated electrode body with a different configuration from the laminated electrode body 3 of the first embodiment will be described.

[0167] Fig. 16 is a diagram showing a battery cell 1R according to this embodiment. As shown in Fig. 16, the battery cell 1R includes an outer case 2, a laminated electrode body 3D, a positive electrode current collector 4, a negative electrode current collector 5, an insulating material 6, and an insulating sheet 9. The laminated electrode body 3D includes a plurality of electrode units 39.

[0168] The electrode units 39 are stacked in the D1 direction. Each electrode unit 39 is connected to a positive electrode current collector 4 and a negative electrode current collector 5. An insulating sheet 9 is provided between the electrode unit 39 on the main body 2a side and the negative electrode current collector 5. More specifically, the insulating sheet 9 is provided between the electrode unit 39 on the main body 2a side and a portion 512 of the negative electrode current collector 5 (see FIG. 2).

[0169] 17 is a diagram showing an electrode unit 39. As shown in Fig. 17, the electrode unit 39 has a plurality of current collector foils 391 for positive electrodes, a plurality of positive electrode layers 392, a plurality of separator layers 393, a plurality of negative electrode layers 394, and a plurality of current collector foils 395 for negative electrodes. In the electrode unit 39, the current collector foils 391, the positive electrode layers 392, the separator layers 393, the negative electrode layers 394, and the current collector foils 395 are stacked in this order in the D1 direction. The separator layers 393 contain a solid electrolyte and a binder.

[0170] In this example, current collecting foil 398, which functions as a tab for electrode unit 39, is connected to two current collecting foils 391. Current collecting foil 399, which functions as a tab for electrode unit 39, is connected to one current collecting foil 395. Current collecting foil 398 is connected to current collecting foil 41 (FIG. 16). Current collecting foil 399 is connected to current collecting foil 51 (FIG. 16).

[0171] The battery cell 1R having such a configuration has the same effects as those of the battery cell 1 according to embodiment 1. In addition, the various modifications described in embodiment 1 can be applied to the battery cell 1G as appropriate.

[0172] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the scope of the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0173] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1P, 1Q, 1R battery cell, 2, 2A outer case, 2a, 2c main body, 2b, 2d lid, 3, 3A, 3C, 3D laminated electrode body, 3B electrode body, 4, 4A, 4B positive electrode current collector, 5, 5A, 5B negative electrode current collector, 6, 6A insulating material, 7 valve, 9 insulating sheet, 21, 21A bottom, 22, 22A, 26, 26A side wall, 25, 25A top, 31, 352, 582 positive electrode, 32, 353, 483 negative electrode, 33, 360 separator, 35, 393 separator layer, 37 outer case, 39 Electrode unit, 41, 41A, 51, 51A, 311, 321, 351, 391, 395, 398, 399, 481, 581 Current collecting foil, 101 Spacer, 102 Frame, 103, 104, 105, 106 Metal layer, 107, 108, 109, 110 Member, 211, 211A, 221, 221A, 251, 251A, 261, 261A Inner wall surface, 212, 212A, 222, 222A, 252, 252A, 262, 262A Outer wall surface, 312, 313, 322, 323 Active material, 350 Bipolar electrode, 392 Positive electrode layer, 394 Negative electrode layer, 411,412,451,452,511,512,551,552 parts, 450 positive electrode plate, 550 negative electrode plate, 800 battery module, 810 positive electrode external terminal, 820 negative electrode external terminal, 830 exhaust duct, 900 press machine, 900A heat press machine, 910 slide, 920 bolster, 4511,4521,5511,5521 inner surface, 4512,4522,5512,5522 outer surface.

Claims

1. an electrode assembly in which positive electrodes and negative electrodes are alternately stacked in a first direction; a first current collecting portion connected to at least one of the positive electrodes; a second current collecting portion connected to at least one of the negative electrodes; an exterior case that houses the electrode body, the first current collecting portion, and the second current collecting portion; the exterior case includes a first case body and a second case body, at least a portion of the first current collecting portion is located between the first case body and the electrode body in the first direction and is electrically connected to the first case body; a battery cell, wherein at least a portion of the second current collecting portion is located between the second case body and the electrode body in the first direction and is electrically connected to the second case body.

2. the first case body has a first base portion to which at least a portion of the first current collecting portion is connected, and a first sidewall portion extending from an outer periphery of the first base portion in a first direction toward the electrode body in the first direction, the second case body has a second base portion facing the first base portion and to which at least a portion of the second current collecting portion is connected, and a second side wall portion extending from an outer periphery of the second base portion in a second direction opposite to the first direction, The battery cell according to claim 1 , wherein the first side wall portion and the second side wall portion partially overlap each other when viewed from a second direction perpendicular to the first direction.

3. The battery cell according to claim 2 , wherein an insulating material is filled between the first side wall portion and the second side wall portion.

4. the first current collecting portion includes a plurality of first current collecting foils each connected to a different positive electrode, Each of the first current collecting foils has a first portion extending in a direction from the positive electrode toward the first base portion; a second portion continuous with the first portion and extending parallel to the first base portion between the first base portion and the electrode body; the second portion is electrically connected to the first case body and faces the negative electrode in the first direction; The battery cell according to claim 2 , wherein the second portion and the negative electrode facing the second portion in the first direction are insulated from each other.

5. the second current collecting portion includes a plurality of second current collecting foils each connected to a different negative electrode, Each of the second current collecting foils has a first portion extending in a direction from the negative electrode toward the second base portion; a second portion that is continuous with the first portion and extends parallel to the second base portion between the second base portion and the electrode body; the second portion is electrically connected to the second case body and faces the positive electrode in the first direction; The battery cell according to claim 2 , wherein the second portion and the positive electrode facing the second portion in the first direction are insulated from each other.

6. The battery cell according to claim 1 , wherein the electrode assembly further comprises a separator layer containing a solid electrolyte between the positive electrode and the negative electrode.

7. 2. The battery cell according to claim 1, wherein one of the first case body and the second case body is a main body of the outer case, and the other is a lid of the outer case.

8. A battery pack according to claim 1, The battery module, wherein the battery cells are stacked in the first direction.

9. a step of placing a battery cell having an electrode assembly in which positive electrodes and negative electrodes are alternately stacked in a first direction, a first current collecting portion connected to at least one of the positive electrodes, and a second current collecting portion connected to at least one of the negative electrodes, so that the first current collecting portion contacts a first case body of an exterior case in the first direction; moving the first case body and the second case body of the exterior case relatively so that the second current collecting portion contacts the second case body in the first direction; and fixing one of the first case body and the second case body to the other.

10. the first case body has a first base portion to which at least a portion of the first current collecting portion is connected, and a first sidewall portion extending from an outer periphery of the first base portion in a first direction toward the electrode body in the first direction, the second case body has a second base portion facing the first base portion and to which at least a portion of the second current collecting portion is connected, and a second side wall portion extending from an outer periphery of the second base portion in a second direction opposite to the first direction, the first side wall portion and the second side wall portion partially overlap each other when viewed from a second direction perpendicular to the first direction, The battery cell manufacturing method according to claim 9 , further comprising the step of filling an insulating material between the first side wall portion and the second side wall portion.

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