Battery cell, battery module and method for producing a battery cell

Abstract

A battery cell (1, 1A to 1H, 1P to 1R) comprises: an electrode assembly (3, 3A to 3D) in which positive electrodes (31, 352, 392) and negative electrodes (32, 353, 394) are alternately stacked in a first direction; a first current collector unit (4, 4A, 4B) connected to at least one of the positive electrodes (31, 352, 392); a second current collector unit (5, 5A, 5B) connected to at least one of the negative electrodes (32, 353, 394); and an outer casing (2, 2A) accommodating the electrode assembly (3, 3A to 3D), the first current collector unit (4, 4A, 4B), and the second current collector unit (5, 5A, 5B). The outer casing (2, 2A) comprises a first casing body and a second casing body. At least a portion of the first current collector unit (4, 4A, 4B) is located between the first casing body and the electrode assembly (3, 3A to 3D) in the first direction and is electrically connected to the first casing body.At least a portion of the second current collector unit (5, 5A, 5B) is located between the second housing body and the electrode assembly (3, 3A to 3D) in the first direction and is electrically connected to the second housing body.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This non-provisional application is based on Japanese Patent Application No. 2024-023400 filed with the Japan Patent Office on February 20, 2024, the entire contents of which are hereby incorporated by reference. BACKGROUND area

[0002] The present invention relates to a battery cell, a battery module and a method for producing a battery cell. Description of the state of the art

[0003] Conventionally, various battery cells are known. For example, JP 2005-310618 A discloses a non-aqueous electrolyte secondary battery as such a battery cell. The non-aqueous electrolyte secondary battery includes a group of electrode plates obtained by spirally winding a positive plate with an active material deposited on a strip current collector and a negative plate with an active material deposited on a strip current collector via a separator. The group of electrode plates and a non-aqueous electrolyte are inserted into a metallic outer casing. The outermost edge of the group of electrode plates consists of a positive current collector on which no active material is deposited. The positive current collector is in contact with the inner wall of the outer casing. SUMMARY

[0004] In the battery cell disclosed in JP 2005-310618 A, the negative current collector unit (the negative current collector) is not in contact with the outer casing. Therefore, there is still room for further improvement in volume efficiency.

[0005] The present invention serves to provide a battery cell with an increased volume efficiency, a battery module containing the battery cell and a method for producing the battery cell.

[0006] According to a specific aspect of the present invention, a battery cell comprises: an electrode assembly in which positive electrodes and negative electrodes are alternately stacked in a first direction; a first current collector unit connected to at least one of the positive electrodes; a second current collector unit connected to at least one of the negative electrodes; and an outer casing accommodating the electrode assembly, the first current collector unit, and the second current collector unit. The outer casing 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 housing body and the electrode assembly in the first direction and is electrically connected to the second housing body.

[0007] In such a configuration, the first current collector unit can cause the first housing body of the outer casing to function as a terminal for the positive electrodes. The second current collector unit can cause the second housing body of the outer casing to function as a terminal for the negative electrodes.

[0008] Furthermore, a portion of the first current collector unit located between the first housing body and the stacked electrode assembly in the first direction is connected to the first housing body. A portion of the second current collector unit located between the second housing body and the stacked electrode assembly in the first direction is connected to the second housing body. Accordingly, the first current collector unit and the second current collector unit are brought into contact with the outer housing while being separated from each other in the first direction.

[0009] Therefore, according to the battery cell, the volumetric efficiency can be increased compared to a battery cell configuration in which only one of the current collector unit for the positive electrodes and the current collector unit for the negative electrodes is in contact with the outer casing.

[0010] Preferably, the first housing body has a first base connected to the at least a portion of the first current collector unit, and a first sidewall extending from an outer periphery of the first base in a first orientation of the first direction, the first orientation facing the electrode assembly. The second housing body has a second base opposite the first base and connected to the at least a portion of the second current collector unit, and a second sidewall extending from an outer periphery of the second base in a second orientation opposite the first orientation. The first sidewall and the second sidewall partially overlap when viewed in a second direction perpendicular to the first direction.

[0011] With such a configuration, the stacked electrode assembly, the first current collector unit, the second current collector unit, and the insulating material can be securely enclosed in the outer casing.

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

[0013] With such a configuration, a short circuit between the first housing body and the second housing body of the outer housing can be prevented.

[0014] Preferably, the first current collector unit comprises a plurality of first current collector foils, each connected to a different positive electrode among the positive electrodes. The first current collector foils each have a first part extending from the positive electrode toward the first base, and a second part adjoining the first part and extending parallel to the first base between the first base and the electrode assembly. The second part is electrically connected to the first housing body and opposite the negative electrode in the first direction. The second part and the negative electrode opposite the second part in the first direction are insulated from each other.

[0015] With such a configuration, a short circuit between the first current collector unit and the negative electrode opposite to a part of the first current collector unit in the first direction can be prevented.

[0016] Preferably, the second current collector unit comprises a plurality of second current collector foils, each connected to a different negative electrode among the negative electrodes. The second current collector foils each have a first part extending from the negative electrode toward the second base, and a second part adjoining the first part and extending parallel to the second base between the second base and the electrode assembly. The second part is electrically connected to the second housing body and opposite the positive electrode in the first direction. The second part and the positive electrode opposite the second part in the first direction are insulated from each other.

[0017] With such a configuration, a short circuit between the second current collector unit and the positive electrode opposite to a part of the second current collector unit in the first direction can be prevented.

[0018] Preferably, the electrode assembly further comprises a separator layer between the positive electrode and the negative electrode, wherein the separator layer contains a solid electrolyte.

[0019] With such a configuration, no injection of the electrolyte solution into the outer casing is required. Thus, the electrode assembly can be subjected to discharge and charge tests before being inserted into the outer casing.

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

[0021] In such a configuration, one of the first case body and the second case body functioning as a main unit is superposed on the other of the first case body and the second case body, thereby accommodating the electrode assembly in the outer case.

[0022] According to another aspect of the present invention, a battery module comprises a plurality of battery cells including the battery cell described above, and the plurality of battery cells are stacked in the first direction.

[0023] With such a configuration, the volumetric efficiency of the battery cell can be improved, thereby improving the volumetric efficiency of the battery module.

[0024] According to another aspect of the present invention, a method for manufacturing a battery cell comprises: assembling a battery cell having: an electrode assembly in which positive electrodes and negative electrodes are alternately stacked in a first direction; a first current collector unit connected to at least one of the positive electrodes; and a second current collector unit connected to at least one of the negative electrodes such that the first current collector unit is in contact with a first case body of an outer case of the battery cell in the first direction; moving the first case body and a second case body of the outer case relative to each other such that the second current collector unit is in contact with the second case body in the first direction;and attaching one of the first housing body and the second housing body to the other of the first housing body and the second housing body;

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

[0026] Preferably, the first housing body comprises a first base connected to at least a portion of the first current collector unit, and a first sidewall extending from an outer periphery of the first base in a first orientation of the first direction, the first orientation facing the electrode assembly. The second housing body comprises a second base opposite the first base and connected to at least a portion of the second current collector unit, and a second sidewall extending from an outer periphery of the second base in a second orientation opposite the first orientation. The first sidewall and the second sidewall partially overlap when viewed in a second direction perpendicular to the first direction. The method for manufacturing a battery cell further comprises introducing an insulating material between the first sidewall and the second sidewall.

[0027] With such a configuration, the second housing body and the first housing body of the outer housing can be insulated from each other. Therefore, a short circuit between the second housing body and the first housing body can be prevented.

[0028] The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a battery cell. Fig. 2 is a diagram showing a positive current collector unit and a negative current collector unit. Fig. 3 is a diagram showing a battery module. Fig. 4 is a diagram showing a method of manufacturing the battery cell. Fig. 5 is a diagram showing a repair method for the battery cell. Fig. 6 is a diagram showing a variation of the battery cell. Fig. Figure 7 is a diagram showing another variation of the battery cell. Fig. Figure 8 is a diagram showing another variation of the battery cell. Fig. Figure 9 is a diagram showing another variation of the battery cell. Fig. Figure 10 is a diagram showing another variation of the battery cell. Fig. Figure 11 is a diagram showing another variation of the battery cell. Fig. 12 is a diagram showing a battery cell according to another embodiment. Fig. 13 is a diagram showing a battery cell according to another embodiment. Fig. 14 is a diagram showing a battery cell according to another embodiment. Fig. 15 is a diagram showing a battery cell according to another embodiment. Fig. 16 is a diagram showing a battery cell according to another embodiment. Fig. 17 is a diagram showing an electrode unit. DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] The embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, the same reference numerals refer to the same elements. Their names and functionalities are also the same. Therefore, a detailed description thereof will not be repeated.

[0030] Various battery cells and battery modules, including the battery cells (described below), are assembled in hybrid electric vehicles that can run on mechanical power from at least one of an electric motor or an internal combustion engine, or in electrically powered vehicles, such as electric vehicles, that run on motive power derived from electrical energy.

[0031] In the following, the terms "upward," "downward," "top," and "bottom" refer to the position of a battery cell during manufacturing. The position of the battery cell during assembly in an electric vehicle may not necessarily correspond to its position during manufacturing. [Embodiment 1](1st battery cell)

[0032] Fig. 1 is a diagram showing a battery cell according to the present embodiment. As shown in Fig. 1, a battery cell 1 comprises an outer casing 2, a stacked electrode assembly 3, a positive current collector unit 4, a negative current collector unit 5, an insulating material 6 and an insulating film 9. It should be noted that in Fig. 1 shows cross sections of the outer casing 2 and the insulating material 6 for better illustration.

[0033] The outer casing 2 houses the stacked electrode assembly 3, the positive current collector unit 4, and the negative current collector unit 5. The outer casing 2 includes a main unit 2a and a cover 2b. The main unit 2a has a bottom surface 21 and a side wall portion 22 projecting upward from the outer periphery of the bottom surface 21. The cover 2b has a top surface 25 opposite the bottom surface 21 and a side wall portion 26 projecting downward from the outer periphery of the top surface 25.

[0034] Note that one of the main unit 2a and the cover 2b corresponds to a "first housing body" according to the present invention, and the other corresponds to a "second housing body" according to the present invention. One of the bottom surface 21 and the top surface 25 corresponds to a "first base" according to the present invention, and the other corresponds to a "second base" according to the present invention.

[0035] The cover 2b is placed on the main unit 2a to cover part of the side wall portion 22 of the main unit 2a. The side wall portion 22 and the side wall portion 26 partially overlap when viewed from the direction D2 perpendicular to the direction D1, that is, the direction in which the stacked electrode assembly 3 is stacked.

[0036] The outer casing 2 typically has a generally cuboid shape. However, the shape of the outer casing 2 is not limited to this. In this example, the outer casing 2 is filled with an electrolyte solution. The interior of the outer casing 2 is under vacuum.

[0037] The bottom surface 21 of the main unit 2a has an inner wall surface 211 and an outer wall surface 212. The side wall portion 22 of the main unit 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 side of the stacked electrode assembly 3.

[0038] The top surface 25 of the cover 2b has an inner wall surface 251 and an outer wall surface 252. The side wall portion 26 of the cover 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 side of the stacked electrode assembly 3. The inner wall surface 251 is opposite to the inner wall surface 211 of the bottom surface 21.

[0039] A gap exists between the side wall portion 22 of the main unit 2a and the side wall portion 26 of the cover 2b. Specifically, a gap exists between the outer wall surface 222 of the side wall portion 22 and the inner wall surface 261 of the side wall portion 26. Specifically, the outer wall surface 222 of the main unit 2a and the inner wall surface 261 of the cover 2b partially oppose each other.

[0040] The insulating material 6 is inserted between the side wall portion 22 and the side wall portion 26. The insulating material 6 is inserted between the outer wall surface 222 and the inner wall surface 261. The insulating material 6 is inserted in a region (gap) where the outer wall surface 222 and the inner wall surface 261 face each other. The insulating material 6 insulates the main unit 2a and the cover 2b from each other. The insulating material 6 enables the cover 2b to be attached to the main unit 2a. The insulating material 6 restricts the movement of the cover 2b toward the main unit 2a in the D1 direction. The insulating material 6 also restricts the movement of the cover 2b toward the main unit 2a in the D2 direction and in one direction (see D3 direction in Fig. 6) perpendicular to the D1 direction and D2 direction.

[0041] The insulating material 6 in this example is a thermoplastic resin. However, the insulating material 6 is not limited to this and may be an adhesive, a thermosetting resin, or a high-viscosity liquid. The insulating material 6 may contain insulating particles. The presence of the insulating particles can more reliably prevent contact between the main unit 2a and the cover 2b.

[0042] The cover 2b is provided with a gas release valve 7. In particular, the side wall portion 26 is provided with the valve 7. The valve 7 allows the gas generated by the stacked electrode assembly 3 to be released from the outer casing 2.

[0043] The stacked electrode assembly 3 includes a plurality of positive electrodes 31, a plurality of negative electrodes 32, and a plurality of separators 33. In the stacked electrode assembly 3, two types of electrodes with different polarities (positive electrode 31 and negative electrode 32) are alternately stacked in the D1 direction over the separator 33. The cover 2b and the main unit 2a exert a constraining force (pressure) on the stacked electrode assembly 3 in the D1 direction. Specifically, the top surface 25 and the bottom surface 21 exert the constraining force on the stacked electrode assembly 3 in the D1 direction.

[0044] In this example, one end of the stacked electrode assembly 3 on the upper surface 25 side is a positive electrode 31. One end of the stacked electrode assembly 3 on the lower surface 21 side is also a positive electrode 31. The insulating film 9 is stacked on the end (positive electrode 31) on the lower surface 21 side. Hereinafter, the positive electrode 31 forming the end on the upper surface 25 side is also referred to as "upper-side positive electrode 31." The positive electrode 31 forming the end on the lower surface 21 side is also referred to as "lower-side positive electrode 31."

[0045] Each positive electrode 31 includes a current collector foil 311 and active materials 312 and 313 coating the opposite surfaces of the current collector foil 311. The active material 312 is located closer to the side of the top surface 25 than the active material 313.

[0046] Each negative electrode 32 includes a current collector foil 321 and active materials 322 and 323 coating the opposing surfaces of the current collector foil 321. The active material 322 is located closer to the side of the top surface 25 than the active material 323.

[0047] Each separator 33 is located between the positive electrode 31 and the negative electrode 32. Each separator 33 is in contact with the active material 313 (or the active material 312) and the active material 322 (or the active material 323). The electrolyte solution permeates each separator 33.

[0048] Each positive electrode 31, each negative electrode 32, each separator 33 and each insulating film 9 expand in the D2 direction and D3 direction (see Fig. 6). (2. Positive current collector unit and negative current collector unit)

[0049] Fig. 2 is a diagram showing the positive current collector unit 4 and the negative current collector unit 5. Hereinafter, the positive current collector unit 4 and the negative current collector unit 5 will be described with reference to the Fig. 1 and Fig. 2 described.

[0050] The positive current collector unit 4 includes a plurality of current collector foils 41 connected to different positive electrodes 31. In this example, the positive current collector units 4 include five current collector foils 41. Each current collector foil 41 has a portion 411 extending from the positive electrode 31 to the top surface 25 and a portion 412 adjoining the portion 411 and extending parallel to the top surface 25 between the top surface 25 and the stacked electrode assembly 3. Therefore, the positive current collector unit 4 has five portions 411 and five portions 412.

[0051] The parts 412 of the current collector foils 41 are collected and stacked in the D1 direction. In this example, the parts 412 of the five current collector foils 41 are stacked in close physical contact with each other in the D1 direction. The parts 412 may or may not be welded together. The parts 411 are different for each current collector foil 41. However, the parts 412 of the current collector foils 41 are the same in this example.

[0052] The parts 412 are located between the cover 2b and the stacked electrode assembly 3 in the D1 direction. The parts 412 are electrically connected to the cover 2b. The parts 412 of the current collector foils 41 are connected to the upper surface 25 of the cover 2b. In particular, a part 412 is in contact with the inner wall surface 251 of the upper surface 25, and pressure is applied to the part 412 in the D1 direction. The parts 412 are opposite the upper-side positive electrode 31 in the D1 direction. The parts 412 are placed on the upper-side positive electrode 31 without being insulated from the upper-side positive electrode 31 of the stacked electrode assembly 3. In this way, the parts 412 are electrically connected to the cover 2b and opposite the upper-side positive electrode 31 of the stacked electrode assembly 3 in the D1 direction.

[0053] In this example, the current collector foil 41 and the current collector foil 311 ( Fig. 1) the positive electrode 31, a piece of foil. In other words, the current collector foil 41 and the current collector foil 311 are formed from one foil. In this example, a region not coated with active materials 312 and 313 corresponds to the current collector foil 41, and a region coated with active materials 312 and 313 corresponds to the current collector foil 311. The current collector foil 41 functions as a terminal for the positive electrode 31. The present invention is not limited to this. The current collector foil 41 and the current collector foil 311 may be separate components. When the current collector foil 41 and the current collector foil 311 are separate components, a terminal portion (an uncoated region) may be provided on the current collector foil 311 to weld the current collector foil 41 to the current collector foil 311.

[0054] The negative current collector unit 5 comprises a plurality of current collector foils 51 connected to different negative electrodes 32. In this example, the negative current collector units 5 comprise four current collector foils 51. Each current collector foil 51 has a portion 511 extending from the negative electrode 32 toward the bottom surface 21, and a portion 512 adjoining portion 511 and extending parallel to the bottom surface 21 between the bottom surface 21 and the stacked electrode assembly 3. Therefore, the negative current collector unit 5 has four portions 511 and four portions 512.

[0055] The parts 512 of the current collector foils 51 are collected and stacked in the D1 direction. In this example, the parts 512 of the four current collector foils 51 are stacked in the D1 direction in close physical contact with each other. The parts 512 may or may not be welded together. The parts 511 are different for each current collector foil 51. In this example, however, the parts 512 of the current collector foils 51 are the same.

[0056] The parts 512 are located between the main unit 2a and the stacked electrode assembly 3 in the D1 direction. The parts 512 are electrically connected to the main unit 2a. The parts 512 of the current collector foils 51 are connected to the bottom surface 21 of the main unit 2a. Specifically, a part 512 is in contact with the inner wall surface 211 of the bottom surface 21, and pressure is applied to the part 512 in the D1 direction. The parts 512 are opposite the bottom-side positive electrode 31 in the D1 direction. The parts 512 are placed on the bottom-side positive electrode 31 while being insulated from the bottom-side positive electrode 31 of the stacked electrode assembly 3.

[0057] In this way, the parts 512 are electrically connected to the main unit 2a and are opposite the lower-side positive electrode 31 of the stacked electrode assembly 3 in the D1 direction. The part 512 and the lower-side positive electrode 31 opposite the part 512 in the D1 direction are insulated from each other. The parts 512 and the lower-side positive electrode 31 are insulated from each other by the insulating film 9.

[0058] In this example, the current collector foil 51 and the current collector foil 321 ( Fig. 1) the negative electrode 32, a piece of foil. In other words, the current collector foil 51 and the current collector foil 321 are made of one foil. In this example, a region not coated with active materials 322 and 323 corresponds to the current collector foil 51, and a region coated with active materials 322 and 323 corresponds to the current collector foil 321. The current collector foil 51 functions as a terminal for the negative electrode 32. The present invention is not limited to this. The current collector foil 51 and the current collector foil 321 may be separate components. When the current collector foil 51 and the current collector foil 321 are separate components, a terminal portion (an uncoated area) may be provided on the current collector foil 321 to weld the current collector foil 51 to the current collector foil 321.

[0059] As in Fig. As shown in Figure 1, the cover 2b of the outer casing 2 is connected to the positive current collector unit 4. The main unit 2a of the outer casing 2 is connected to the negative current collector unit 5. The cover 2b and the main unit 2a are insulated from each other by insulating material 6. Accordingly, the battery cell 1 can cause the cover 2b to function as the positive terminal and the main unit 2a to function as the negative terminal. (3. Summary of the battery cell)

[0060] (1) The battery cell 1 includes: (i) a stacked electrode assembly 3 in which negative electrodes 32 and positive electrodes 31 are alternately stacked in the D1 direction; (ii) a negative current collector unit 5 connected to the negative electrodes 32; (iii) a positive current collector unit 4 connected to the positive electrodes 31; and (iv) an outer casing 2 that houses the stacked electrode assembly 3, the negative current collector units 5, and the positive current collector units 4. The outer casing 2 includes the main unit 2a and the cover 2b. Parts 512 of the negative current collector unit 5 are located between the main unit 2a and the stacked electrode assembly 3 in the D1 direction and are electrically connected to the main unit 2a. Parts 412 of the positive current collector unit 4 are located between the cover 2b and the stacked electrode assembly 3 in the D1 direction and are electrically connected to the cover 2b.

[0061] In such a configuration, the negative current collector unit 5 can cause the main unit 2a of the outer casing 2 to function as the negative terminal. The positive current collector unit 4 can cause the cover 2b of the outer casing 2 to function as the positive terminal.

[0062] Furthermore, the negative current collector unit 5 is connected to the main unit 2a through parts 512 located between the main unit 2a and the stacked electrode assembly 3 in the D1 direction. The positive current collector unit 4 is connected to the cover 2b through parts 412 located between the cover 2b and the stacked electrode assembly 3 in the D1 direction. Accordingly, the positive current collector unit 4 and the negative current collector unit 5 can be brought into contact with the outer casing 2 while being separated from each other in the D1 direction.

[0063] Therefore, according to the battery cell 1, the volumetric efficiency can be increased compared to a battery cell configuration in which only one of the negative current collector unit and the positive current collector unit is in contact with the outer casing.

[0064] (2) The main unit 2a has a bottom surface 21 connected to the parts 512 of the negative current collector unit 5, and a side wall portion 22 projecting upward from the outer periphery of the bottom surface 21. The cover 2b has a top surface 25 opposite the bottom surface 21 and connected to the parts 512 of the positive current collector unit 4, and a side wall portion 26 projecting downward from the outer periphery of the top surface 25. The side wall portion 22 and the side wall portion 26 partially overlap when viewed from the D2 direction perpendicular to the D1 direction. With such a configuration, the stacked electrode assembly 3, the positive current collector unit 4, the negative current collector unit 5, and the insulating material 6 can be securely enclosed in the outer casing 2.

[0065] (3) The insulating material 6 is inserted between the side wall 22 and the side wall 26. With such a configuration, a short circuit between the main unit 2a and the cover 2b of the outer casing 2 can be prevented.

[0066] (4) The negative current collector unit 5 includes a plurality of current collector foils 51 connected to different negative electrodes 32. Each current collector foil 51 has a part 511 extending from the negative electrode 32 toward the bottom surface 21, and a part 512 adjoining part 511 and extending parallel to the bottom surface 21 between the bottom surface 21 and the stacked electrode assembly 3. The parts 512 are electrically connected to the main unit 2a and opposite the positive electrode 31 in the D1 direction. The parts 512 and the positive electrode 31 (i.e., the bottom-side positive electrode 31) opposite the parts 512 in the D1 direction are insulated from each other. With such a configuration, a short circuit between the negative current collector unit 5 and the positive electrode 31 opposite the parts 512 of the negative current collector unit 5 in the D1 direction can be prevented.

[0067] (5) The positive current collector unit 4 includes a plurality of current collector foils 41 connected to different positive electrodes 31. Each current collector foil 41 has a portion 411 extending from the positive electrode 31 toward the top surface 25, and a portion 412 adjoining portion 411 and extending parallel to the top surface 25 between the top surface 25 and the stacked electrode assembly 3. The portions 412 are electrically connected to the cover 2b. (4th battery module)

[0068] Fig. 3 is a diagram showing a battery module. As shown in Fig. As shown in Figure 3, a battery module 800 includes a plurality of battery cells 1, a positive external terminal 810, a negative external terminal 820, and an exhaust duct 830. In the battery module 800, the battery cells 1 are connected in series. In this example, four battery cells 1 are stacked in the D1 direction.

[0069] Note that, for convenience, a battery cell 1 on the positive external terminal 810 side is also referred to as a "first battery cell 1" hereinafter. A battery cell 1 on the negative external terminal 820 side is also referred to as a "fourth battery cell 1." A battery cell 1 adjacent to the first battery cell 1 is also referred to as a "second battery cell 1." A battery cell 1 adjacent to the fourth battery cell 1 is also referred to as a "third battery cell 1."

[0070] The first battery cell 1 is in contact with the positive external terminal 810. More specifically, the cover 2b of the first battery cell 1 is in contact with the positive external terminal 810. More specifically, the top surface 25 of the cover 2b is in contact with the positive external terminal 810. The main unit 2a of the first battery cell 1 is in contact with the cover 2b of the second battery cell 1. More specifically, the bottom surface 21 of the main unit 2a is in contact with the top surface 25 of the cover 2b.

[0071] Likewise, the bottom side 21 of the main unit 2a of the second battery cell 1 is in contact with the top side 25 of the cover 2b of the third battery cell 1. The bottom side 21 of the main unit 2a of the third battery cell 1 is in contact with the top side 25 of the cover 2b of the fourth battery cell 1.

[0072] The fourth battery cell 1 is in contact with the negative external terminal 820. In particular, the main unit 2a of the fourth battery cell 1 is in contact with the negative external terminal 820. More specifically, the bottom surface 21 of the main unit 2a is in contact with the negative external terminal 820.

[0073] Thus, the battery cells 1 are stacked and connected such that the main unit 2a of one battery cell 1 and the cover 2b of another battery cell 1 are in contact, thereby manufacturing the battery module 800. Accordingly, the battery module 800 with a high volumetric efficiency can be easily manufactured.

[0074] The exhaust duct 830 is connected to the valves 7 in the side walls 26 of the covers 2b of the outer housings 2. The exhaust duct 830 covers the respective valves 7. The exhaust duct 830 is partially in contact with the side wall 26 of the cover 2b of each outer housing 2.

[0075] The respective valves 7 and the exhaust duct 830 allow the gases generated by the respective stacked electrode assemblies 3 to be discharged from the outer casings 2. The discharged gas is treated by a downstream device to prevent untreated gas from escaping to the outside. (5. Manufacturing process for battery cells)

[0076] Fig. 4 is a diagram illustrating a method for manufacturing a battery cell 1. As in Fig. 4, a pressing machine 900 comprises a carriage 910 and a support 920 arranged directly below the carriage 910.

[0077] The battery cell 1 with the insulating material 6 before solidification is mounted on the support 920. The battery cell 1 is stacked on the support 920 such that the direction (D1) in which the stacked electrode assembly 3 is stacked is the vertical direction. The battery cell 1 is mounted on the support 920 such that the bottom surface 21 of the main unit 2a of the outer casing 2 is in contact with the support 920.

[0078] The pressing machine 900 applies a force to the battery cell 1 to compress the battery cell 1 in the D1 direction in the orientations indicated by arrows A1 and A2. Specifically, the carriage 910 is lowered to apply a force in the D1 direction to the battery cell 1. This exerts the force in the D1 direction on the stacked electrode assembly 3. In this state, the insulating material 6 is solidified. By solidifying the insulating material 6, the cover 2b is fixed to the main unit 2a. Therefore, even when the carriage 910 is raised, the cover 2b and the main unit 2a can continue to apply the force in the D1 direction (a constraining force) to the stacked electrode assembly 3. In other words, surface pressure can be applied to the stacked electrode assembly 3.

[0079] In particular, since the support 920 and the slide 910 exert the force in the D1 direction on the battery cell 1 before the insulating material 6 is solidified, the load in the D1 direction can be prevented from being concentrated on the side wall 26 of the cover 2b and the side wall 22 of the main unit 2a.

[0080] The method for manufacturing the battery cell 1 includes: a step of assembling the battery cell 1 with the stacked electrode assembly 3, in which negative electrodes 32 and positive electrodes 31 are alternately stacked in the D1 direction, to the main unit 2a by a transfer machine (not shown), with the negative current collector unit 5 connected to the negative electrodes 32 and the positive electrodes 31 connected to the positive current collector unit 4, so that the negative current collector unit 5 is brought into contact with the outer casing 2 of the main unit 2a in the D1 direction; and a step of moving the cover 2b by the transfer machine so that the positive current collector unit 4 is brought into contact with the cover 2b of the outer casing 2 in the D1 direction. In this example, the movement sets the cover 2b on the main unit 2a.The method further includes a step of attaching the cover 2b to the main unit 2a. According to such a method, the manufacturing efficiency of the battery cell 1 can be improved.

[0081] In this example, the cover 2b is attached to the main unit 2a with the outer casing 2 compressed in the D1 direction by the pressing machine 900, and the cover 2b and the main unit 2a are insulated from each other. However, depending on the component materials of the battery, the cover 2b may be attached to the main unit 2a as described above without isolating the cover 2b and the main unit 2a from each other. Note that the process of attaching the cover 2b to the main unit 2a is generally performed by a machine (not shown).

[0082] In the above illustration, the cover 2b is fitted onto the main unit 2a by moving the cover 2b. The present invention is not limited to this. The main unit 2a may be moved instead of moving the cover 2b. The cover 2b and the main unit 2a may be moved. The main unit 2a and the cover 2b may be moved relative to each other.

[0083] The method further includes a step of inserting insulating material 6 between the side wall 22 and the side wall 26. According to such a method, the cover 2b and the main unit 2a can be insulated from each other. Thus, a short circuit between the cover 2b and the main unit 2a can be prevented. (6. Repair procedures for battery cells)

[0084] Fig. 5 is a diagram illustrating a repair method for the battery cell 1. The use of the battery cell 1 can reduce the thickness of the stacked electrode assembly 3. In particular, the use of the battery cell 1 reduces the thickness of the stacked electrode assembly 3 in the D1 direction compared to the initial state shown in state (A) of Fig. 5. When this happens, the force in the D1 direction (the constraining force, the surface pressure) exerted on the stacked electrode assembly 3 ceases to exist, as shown in state (B). Note that state (B) represents a gap formed between the parts 412 of the positive current collector unit 4 and the top surface 25 of the outer casing 2.

[0085] In this case, the battery cell 1 is treated with a heating press 900A as follows: The battery cell 1 is mounted on the support 920 of the heating press 900A. Then, the carriage of the heating press 900A is lowered to the position of the upper surface 25 of the cover 2b, as shown in state (C). In this state, heat is applied to the battery cell 1. Specifically, heat is applied from at least one of the carriage 910 and the support 920 to the outer casing 2. The heat transferred to the outer casing 2 is also transferred to the insulating material 6. This softens the solidified (hardened) insulating material 6.

[0086] As the insulating material 6 softens, the carriage 910 is further moved downward, as shown in state (D). Specifically, the carriage 910 is moved in the direction of arrow B. This exerts the force in the D1 direction on the stacked electrode assembly 3. In this state, the heat supply is stopped, and the insulating material 6 solidifies. By solidifying the insulating material 6, the cover 2b is fixed to the main unit 2a. Therefore, even with the carriage 910 raised, the cover 2b and the main unit 2a can continue to exert the force in the D1 direction on the stacked electrode assembly 3. In this way, the surface pressure can be applied again to the stacked electrode assembly 3 by reducing the thickness of the outer casing 2 in the D1 direction using the heating press 900A. This can restore the performance of the battery cell 1. <variationen>

[0087] Several variations of battery cell 1 are described below. Similar to battery cell 1, these variations can also increase the volumetric efficiency compared to the battery cell configuration in which only one of the negative current collector unit and the positive current collector unit is in contact with the outer casing. (Variation 1)

[0088] As mentioned above in the Fig. 1, Fig. 2, etc., the positive current collector unit 4 is connected to the cover 2b of the outer casing 2, and the negative current collector unit 5 is connected to the main unit 2a of the outer casing 2. However, the present invention is not limited to this. The positive current collector unit 4 may be connected to the main unit 2a of the outer casing 2, and the negative current collector unit 5 may be connected to the cover 2b of the outer casing 2. In this case, the main unit 2a side is the positive electrode of the battery cell 1, and the cover 2b side is the negative electrode of the battery cell 1. (Variation 2)

[0089] In the stacked electrode assembly 3, the electrodes at the opposite ends of the stack are positive electrodes 31. However, the present invention is not limited thereto. The stacked electrode assembly 3 can be configured so that the negative electrodes 32 are the opposite ends of the stack.

[0090] Alternatively, the stacked electrode assembly 3 may be configured such that the positive electrode 31 is the end on the main unit 2a side, and the negative electrode 32 is the end on the cover 2b side. With such a configuration, the parts 412 are electrically connected to the cover 2b and are opposite to the negative electrode 32 in the D1 direction. Therefore, the part 412 and the negative electrode 32 opposite to the parts 412 in the D1 direction are insulated from each other by an insulating film (not shown). With such a configuration, a short circuit between the positive current collector unit 4 and the negative electrode 32 opposite to the parts 412 of the positive current collector unit 4 in the D1 direction can be prevented.

[0091] The stacked electrode assembly 3 can also be configured so that the negative electrode 32 is the end on the main unit 2a side and the positive electrode 31 is the end on the cover 2b side. Even with this configuration, a short circuit can be prevented by properly disposing the insulating film. (Variation 3)

[0092] Fig. 6 is a diagram showing variation 3 of the battery cell 1. In Fig. 6, the cover 2b of the outer casing 2 is not shown for clarity. As in Fig. 6, a battery cell 1A includes a spacer 101 in addition to the outer casing 2, the stacked electrode assembly 3, the positive current collector unit 4, the negative current collector unit 5, and the insulating material 6. The battery cell 1A differs from the battery cell 1 in that the battery cell 1A includes the spacer 101.

[0093] The spacer 101 is an insulating member. The spacer 101 is arranged between the stacked electrode assembly 3 and the main unit 2a of the outer casing 2. More specifically, the spacer 101 is arranged inside the main unit 2a along the inner wall surface 221 (see Fig. 1) of the side wall 22 of the main unit 2a. The stacked electrode assembly 3 is surrounded by the spacer 101. 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 part 411 of the current collector foil 41 and part 511 of the current collector foil 51.

[0094] With such a configuration, the spacer 101 can prevent misalignment of the stacked electrode assembly 3 within the outer casing 2. In particular, the spacer 101 can prevent the stacked electrode assembly 3 from moving in the D2 direction and D3 direction within the outer casing 2. (Variation 4)

[0095] Fig. Figure 7 is a diagram showing variation 4 of the battery cell 1. As shown in Fig. 7, a battery cell 1B includes, in addition to the outer casing 2, the stacked electrode assembly 3, the positive current collector unit 4, the negative current collector unit 5, and the insulating material 6, a positioning frame 102. The battery cell 1B differs from the battery cell 1 in that the battery cell 1B includes the frame 102. It should be noted that Fig. 7 shows a cross-section of part of the frame 102.

[0096] The frame 102 extends upwards from the side wall 26 of the cover 2b in the D1 direction. In particular, the frame 102 extends from the outer wall surface 262 (see Fig. 1) the side wall 26 is oriented upward in an orientation opposite to the orientation of the main unit 2a. The frame 102 protrudes from the top surface 25 in the D1 direction. When the outer casing 2 is viewed from the side of the cover 2b in the D1 direction, the frame 102 has a rectangular frame shape with an opening along the side wall 26.

[0097] With such a configuration, misalignment between the battery cells 1B can be prevented when stacking the battery cells 1B. (Variation 5)

[0098] Fig. Figure 8 is a diagram showing variation 5 of the battery cell 1. As shown in Fig. 8, a battery cell 1C similar to the battery cell 1 includes an outer casing 2, a stacked electrode assembly 3, a positive current collector unit 4, a negative current collector unit 5, and insulating material 6. In the battery cell 1C, the main unit 2a and the cover 2b of the outer casing 2 are covered with a material having high electrical conductivity.

[0099] Specifically, the inner wall surface 211 of the bottom surface 21 of the main unit 2a is covered with a highly conductive metal layer 103. The outer wall surface 212 of the bottom surface 21 is covered with a highly conductive metal layer 104. Similarly, the inner wall surface 251 of the top surface 25 is covered with a highly conductive metal layer 105. The outer wall surface 252 of the top surface 25 is covered with a highly conductive metal layer 106. For example, the metal layers 103 to 106 may be made of the same metal.

[0100] With such a configuration, the battery module consisting of stacked battery cells 1C as shown in Fig. 3, compared to the configuration in which the outer casing 2 is not covered with a highly conductive metal layer, reduce the electrical resistance between adjacent battery cells 1C. (Variation 6)

[0101] Fig. 9 is a diagram showing variation 6 of the battery cell 1. As in Fig. As shown in Figure 9, a battery cell 1D includes the outer casing 2, the stacked electrode assembly 3, the positive current collector unit 4, and the negative current collector unit 5. Unlike the battery cell 1, the battery cell 1D does not include an insulating material 6. However, like the battery cell 1, the main unit 2a and the cover 2b of the outer casing 2 of the battery cell 1D need to be insulated. For this reason, the battery cell 1D has the following configuration.

[0102] In the battery cell 1D, the side wall 22 of the main unit 2a and the side wall 26 of the cover 2b of the outer casing 2 were previously 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.

[0103] With such a configuration, the outer wall surface 222 of the side wall 22 and the inner wall surface 261 of the side wall 26 do not come into contact with each other. Therefore, a short circuit between the main unit 2a and the cover 2b can be prevented.

[0104] Viewed from the D2 direction, the overlapping portions of the main unit 2a and the cover 2b overlap with the insulating members 107 and 108. This can better prevent a short circuit between the main unit 2a and the cover 2b than in a configuration without insulating members. (Variation 7)

[0105] Fig. 10 is a diagram showing variation 7 of the battery cell 1. As in Fig. 10, a battery cell 1E includes the outer casing 2, the stacked electrode assembly 3, the positive current collector unit 4, and the negative current collector unit 5. As with the battery cell 1D, the battery cell 1E does not include an insulating material 6.

[0106] In the battery cell 1E, the side wall 22 of the main unit 2a and the side wall 26 of the cover 2b of the outer casing 2 were previously insulated. 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.

[0107] With such a configuration, the element 110 prevents contact between the main unit 2a and the cover 2b of the outer casing 2. Therefore, a short circuit between the main unit 2a and the cover 2b can be prevented. Furthermore, the element 109 prevents contact between the outer casing 2 and the stacked electrode assembly 3. In particular, the side wall 22 of the outer casing 2 and the stacked electrode assembly 3 do not come into contact. Therefore, a short circuit between the main unit 2a and the stacked electrode assembly 3 can be prevented.

[0108] Note that, as with the battery cell 1D described above, the outer wall surface 222 of the side wall 22 of the main unit 2a may also be insulated in advance. In other words, the inner wall surface 221 and the outer wall surface 222 of the side wall 22 may be insulated in advance. Furthermore, the outer wall surface 262 of the side wall of the cover 2b may be insulated in advance. In other words, the inner wall surface 261 and the outer wall surface 262 of the side wall 26 may be insulated.

[0109] Regardless, at least one of the outer wall surface 222 of the sidewall 22 and the inner wall surface 261 of the sidewall 26 may be insulated. Preferably, as in the battery cell 1D, both the outer wall surface 222 of the sidewall 22 and the inner wall surface 261 of the sidewall 26 are insulated.

[0110] Preferably, the outer wall surfaces 222 and 262 are insulated. With such a configuration, a short circuit between the battery cell 1 and an object outside the battery cell 1 can be prevented. (Variation 8)

[0111] Fig. 11 is a diagram showing variation 8 of the battery cell 1. As in Fig. 11, a battery cell 1F includes an outer casing 2, a stacked electrode assembly 3, a positive current collector unit 4A, a negative current collector unit 5A, and insulating material 6. The battery cell 1F differs from the battery cell 1 in that the battery cell 1F includes the positive current collector unit 4A and the negative current collector unit 5A, while the battery cell 1 includes the positive current collector unit 4 and the negative current collector unit 5.

[0112] The positive current collector unit 4A comprises a plurality of current collector foils 41A and an L-shaped positive plate 450. The positive plate 450 has a part 451 extending in the D1 direction and a part 452 adjoining part 451 and extending parallel to the top surface 25 between the top surface 25 and the stacked electrode assembly 3.

[0113] Part 451 has an inner side surface 4511 on the stacked electrode assembly 3 side and an outer side surface 4512 opposite the inner side surface 4511. Part 452 has an inner side surface 4521 on the stacked electrode assembly 3 side and an outer side surface 4522 opposite the inner side surface 4521. The inner side surface 4521 is in contact with the top-side positive electrode 31. The outer side surface 4522 is in contact with the top surface 25 of the outer casing 2. In particular, the outer side surface 4522 is in contact with the inner wall surface 251 of the top surface 25.

[0114] In this example, the current collector foil 41A and the current collector foil 311 of the positive electrode 31 are one piece of foil. The current collector foils 41A are collected and welded to the part 451 of the positive plate 450. Specifically, the current collector foils 41A are welded to the inner side surface 4511 of the part 451.

[0115] The negative current collector unit 5A comprises a plurality of current collector foils 51A and an L-shaped negative plate 550. The negative plate 550 has a part 551 extending in the D1 direction and a part 552 adjoining part 551 and running parallel to the bottom surface 21 between the bottom surface 21 and the stacked electrode assembly 3.

[0116] Part 551 has an inner side surface 5511 on the stacked electrode assembly 3 side and an outer side surface 5512 opposite the inner side surface 5511. Part 552 has an inner side surface 5521 on the stacked electrode assembly 3 side and an outer side surface 5512 opposite the inner side surface 5521. The inner side surface 5521 is in contact with the insulating film 9. The outer side surface 5512 is in contact with the bottom surface 21 of the outer casing 2. More specifically, the outer side surface 5512 is in contact with the inner wall surface 211 of the bottom surface 21.

[0117] In this example, the current collector foil 51A and the current collector foil 321 of the negative electrode 32 are one piece of foil. The current collector foils 51A are collected and welded to the part 551 of the negative plate 550. Specifically, the current collector foils 51A are welded to the inner side surface 5511 of the part 551.

[0118] According to the above configuration, for example, a size reduction of the battery cell 1F compared to the battery cell 1 can be achieved by reducing the combined thickness of the positive plate 450 and the negative plate 550 to less than the thickness of the superposed current collector foils 41A.

[0119] Furthermore, according to the above configuration, for example, by increasing the combined thickness of the positive plate 450 and the negative plate 550 to be greater than the thickness of the superimposed current collector foils 41A, the resistances at the positive current collector unit 4A and the negative current collector unit 5A can be reduced to be lower than the resistances at the positive current collector unit 4 and the negative current collector unit 5 of the battery cell 1. Therefore, current fluctuations within the surface of the negative current collector unit 5A in contact with the bottom surface 21 and the surface of the positive current collector unit 4A in contact with the top surface 25 can be reduced. This can uniform the temperature distributions in part 452 and part 552.

[0120] Furthermore, according to the above configuration, for example, by using metals with higher electrical conductivity than the electrical conductivities of the current collector foils 41A and 51A to form the positive current collector unit 4A and the negative current collector unit 5A, the resistances at the positive current collector unit 4A and the negative current collector unit 5A can be reduced to less than the resistances at the positive current collector unit 4 and the negative current collector unit 5 of the battery cell 1. Therefore, current fluctuations in the surface of the negative current collector unit 5A in contact with the bottom surface 21 and the surface of the positive current collector unit 4A in contact with the top surface 25 can be reduced. This allows the temperature distributions in part 452 and part 552 to be uniformed.

[0121] Preferably, the surfaces of the current collector foils 41A are insulated. With such a configuration, a short circuit between the current collector foils 41A and the main unit 2a of the outer casing 2 can be prevented. Likewise, the surfaces of the current collector foils 51A are preferably insulated. With such a configuration, a short circuit between the current collector foils 51A and the cover 2b of the outer casing 2 can be prevented. [Embodiment 2]

[0122] Embodiment 1 has been described, in which the electrolyte solution is injected into the outer casing 2 and the stacked electrode assembly 3 includes a separator 33. In the present embodiment, the battery cell is an all-solid-state battery that does not require an electrolyte solution.

[0123] Fig. 12 is a diagram showing a battery cell 1G according to the present embodiment. As shown in Fig. 12, the battery cell 1G includes an outer casing 2, a stacked electrode assembly 3A, a positive current collector unit 4, a negative current collector unit 5, an insulating material 6, and an insulating film 9. The battery cell 1G differs from the battery cell 1 in that the battery cell 1G includes a stacked electrode assembly 3A instead of the stacked electrode assembly 3. The following describes a configuration of the battery cell 1G, focusing on the differences from the battery cell 1.

[0124] The stacked electrode assembly 3A includes a plurality of positive electrodes 31, a plurality of negative electrodes 32, and a plurality of separator layers 35. The stacked electrode assembly 3A differs from the stacked electrode assembly 3 in that the stacked electrode assembly 3A includes separator layers 35 instead of the separators 33. Each separator layer 35 includes a solid electrolyte and a binder.

[0125] In the stacked electrode assembly 3A, positive electrodes 31 and negative electrodes 32 are alternately stacked in the D1 direction via separator layers 35. In other words, the stacked electrode assembly 3A has a separator layer 35 between the positive electrode 31 and the negative electrode 32. Note that, similar to the stacked electrode assembly 3, a constraining force (pressure) in the D1 direction is applied to the stacked electrode assembly 3A by a cover 2b and a main unit 2a.

[0126] Since the battery cell 1G does not require the injection of the electrolyte solution into the outer casing 2, the battery cell 1G is easy to manufacture compared to the battery cell 1. Furthermore, the battery cell 1G offers the same advantages as the battery cell 1 according to Embodiment 1. Furthermore, the variations of Embodiment 1 described above are applicable to the battery cell 1G, if necessary. [Embodiment 3]

[0127] Embodiment 2 was described with reference to the battery cell 1G including a stacked electrode assembly 3A. In the present embodiment, one battery cell includes a plurality of stacked electrode assemblies 3A.

[0128] Fig. 13 is a diagram showing a battery cell 1H according to the present embodiment. As shown in Fig. As shown in FIG. 13, the battery cell 1H includes an outer casing 2A, three stacked electrode assemblies 3A, three positive current collector units 4, three negative current collector units 5, and an insulating material 6A. The three stacked electrode assemblies 3A are aligned in the D1 direction. The three positive current collector units 4 and the three negative current collector units 5 are also aligned in the D1 direction. Note that the number of stacked electrode assemblies 3A, the number of positive current collector units 4, and the number of negative current collector units 5 are not limited to three and may be at least two.

[0129] The outer casing 2A includes a main unit 2c and a cover 2d. The main unit 2c has a bottom surface 21A and a side wall 22A extending upward from the outer edge of the bottom surface 21A. The cover 2d has a top surface 25A opposite the bottom surface 21A and a side wall 26A extending downward from the outer edge of the top surface 25A.

[0130] The cover 2d is placed on the main unit 2c to cover a portion of the side wall 22A of the main unit 2c. The side wall 22A and the side wall 26A partially overlap when viewed from the D2 direction perpendicular to the D1 direction in which the stacked electrode assemblies 3A are stacked.

[0131] Like the outer casing 2, the outer casing 2A typically has a generally parallelepiped or cuboid shape. However, the shape of the outer casing 2A is not limited thereto.

[0132] The bottom surface 21A of the main unit 2c has an inner wall surface 211A and an outer wall surface 212A. The side wall 22A of the main unit 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 side of the stacked electrode assembly 3A.

[0133] The bottom surface 21A has the same function as the bottom surface 21 according to Embodiment 1. The bottom surface 21A has the same shape as the bottom surface 21. The side wall 22A has the same function as the side wall 22 according to Embodiment 1. Since a plurality of stacked electrode assemblies 3A are accommodated in one outer casing 2A, the length of the side wall 22A in the D1 direction is longer than the length of the side wall 22 in the D1 direction.

[0134] The top surface 25A of the cover 2d has an inner wall surface 251A and an outer wall surface 252A. The side wall 26A of the cover 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 side of the stacked electrode assembly 3A. The inner wall surface 251A is opposite the inner wall surface 211A of the bottom surface 21A.

[0135] The top surface 25A has the same function as the top surface 25 according to Embodiment 1. The top surface 25A has the same shape as the top surface 25. The side wall 26A has the same function as the side wall 26 according to Embodiment 1. Since a plurality of stacked electrode assemblies 3A are accommodated in the outer casing 2A, the length of the side wall 26A in the D1 direction is longer than the length of the side wall 26 in the D1 direction.

[0136] There is a gap between the side wall 22A of the main unit 2c and the side wall 26A of the cover 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. Specifically, a portion of the outer wall surface 222 of the main unit 2a and a portion of the inner wall surface 261 of the cover 2b oppose each other.

[0137] Insulating material 6A is interposed between the side wall 22 and the side wall 26. The insulating material 6A is interposed between the outer wall surface 222A and the inner wall surface 261A. The insulating material 6A is interposed in a region (gap) where the outer wall surface 222A and the inner wall surface 261A oppose each other. The insulating material 6A insulates the main unit 2c and the cover 2d from each other. The cover 2d is fixed to the main unit 2c by the insulating material 6A. The insulating material 6A restricts the movement of the cover 2d relative to the main unit 2c in the D1 direction, D2 direction, and D3 direction.

[0138] The insulating material 6A is made of the same material as the insulating material 6 according to Embodiment 1. Note that in this example, the length of the insulating material 6A in the D1 direction is greater than the length of the insulating material 6 in the D1 direction. Similar to the cover 2b according to Embodiment 1, the cover 2d is provided with a gas vent 7.

[0139] Hereinafter, the stacked electrode assembly 3A on the top side 25 is also referred to as the "stacked top-side electrode assembly 3A" for the sake of simplicity. The stacked electrode assembly 3A on the bottom side 21 is also referred to as the "stacked bottom-side electrode assembly 3A." The stacked electrode assembly 3A between the stacked top-side electrode assembly 3A and the stacked bottom-side electrode assembly 3A on the bottom side is also referred to as the "stacked intermediate electrode assembly 3A."

[0140] Likewise, the positive current collector unit 4 and the negative current collector unit 5 connected to the stacked upper-side electrode assembly 3A are also referred to as the "upper-side positive current collector unit 4" and the "upper-side negative current collector unit 5," respectively. Similarly, the positive current collector unit 4 and the negative current collector unit 5 connected to the stacked intermediate electrode assembly 3A are also referred to as the "positive intermediate current collector unit 4" and the "negative intermediate current collector unit 5," respectively. The positive current collector unit 4 and the negative current collector unit 5 connected to the stacked lower-side electrode assembly 3A are also referred to as the "lower-side positive current collector unit 4" and the "lower-side negative current collector unit 5," respectively.

[0141] In the battery cell 1H, the parts 412 of the current collector foils 41 in the upper-side positive current collector unit 4 are connected to the upper surface 25A of the cover 2d. The parts 512 of the current collector foils 51 in the upper-side negative current collector unit 5 and the parts 412 of the current collector foils 41 in the positive intermediate current collector unit 4 overlap on the upper surface, so that they contact each other in the D1 direction. Likewise, the parts 512 of the current collector foils 51 in the negative intermediate current collector unit 5 and the parts 412 of the current collector foils 41 in the lower-side positive current collector unit 4 overlap on the upper surface, so that they contact each other in the D1 direction. The parts 512 of the current collector foils 51 in the lower side negative current collector unit 5 are connected to the lower side 21A of the main unit 2c.

[0142] Since the stacked electrode assembly 3A has separator layers 35 instead of separators 33, the stacked electrode assembly 3A can be subjected to discharge and charge tests before being inserted into the outer casing 2A. Therefore, only stacked electrode assemblies 3A that are determined to be free of defects are inserted into the outer casing 2A, thereby ensuring the quality of the battery cell 1H. Furthermore, the battery cell 1H offers the same advantages as the battery cell 1 according to Embodiment 1. Furthermore, the variations of Embodiment 1 described above are also applicable to the battery cell 1H, where appropriate.

[0143] The battery cell 1H includes a plurality of stacked electrode assemblies 3A. Therefore, the battery cell 1H can have performance equal to or better than that of the battery cell 1, even though the number of positive electrodes 31 and negative electrodes 32 included in each stacked electrode assembly 3A is reduced to less than the number of stacked electrode assemblies 3 included in the battery cell 1. Furthermore, since the number of positive electrodes 31 and negative electrodes 32 included in the stacked electrode assembly 3A can be reduced as described above, the rejection rate of the stacked electrode assemblies 3A can be reduced. [Embodiment 4]

[0144] Embodiments 1 to 3 have been described with reference to battery cells 1 and 1A to 1H including stacked electrode assemblies 3 and 3A. In the present embodiment, a battery cell includes a wound electrode assembly.

[0145] Fig. 14 is a diagram showing a battery cell 1P according to the present embodiment. As shown in Fig. As shown in Fig. 14, the battery cell 1P includes an outer casing 2, a wound electrode assembly 3B, a positive current collector unit 4, and a negative current collector unit 5.

[0146] Battery cell 1P differs from battery cells 1 and 1A to 1H according to Embodiments 1 to 3 in that battery cell 1P includes a wound electrode assembly 3B instead of stacked electrode assemblies 3 and 3A. Furthermore, battery cell 1P differs from battery cells 1 and 1A to 1H according to Embodiments 1 to 3 in that battery cell 1P does not include an insulating film 9.

[0147] The wound electrode assembly 3B has an insulating outer body 37. The wound electrode assembly 3B has a winding axis extending in the D3 direction (see Fig. 6) extends perpendicular to the D1 direction and D2 direction, and is constructed from a stack including a positive ribbon electrode, a negative ribbon electrode, and a ribbon separator spirally wound around the winding axis. Specifically, the wound electrode assembly 3B includes the spirally wound stack and an electrolyte solution housed in the outer body 37.

[0148] In the wound electrode assembly 3B, the positive electrodes and the negative electrodes are alternately stacked from the winding axis to the outer peripheral side. Therefore, it can be said that in the wound electrode assembly 3B, the positive electrodes and the negative electrodes are alternately stacked at least in the D1 direction.

[0149] In this example, four current collector foils 41 are connected to the positive strip electrode. Each current collector foil 41 acts as the positive terminal of the wound electrode assembly 3B. Similarly, four current collector foils 51 are connected to the negative strip electrode. Each current collector foil 51 acts as the negative terminal of the wound electrode assembly 3B.

[0150] The battery cell 1H having the above configuration offers the same advantages and effects as the battery cell 1 according to Embodiment 1. In addition, the variations of Embodiment 1 described above are applicable to the battery cell 1G as appropriate. [Embodiment 5]

[0151] Embodiments 1 to 3 were described with reference to stacked electrode assemblies 3 and 3A as monopolar electrode assemblies. The present embodiment will be described with reference to a bipolar type stacked electrode assembly.

[0152] Fig. 15 is a diagram showing a battery cell 1Q according to the present embodiment. As shown in Fig. As shown in FIG. 15, the battery cell 1Q includes an outer casing 2, a stacked electrode assembly 3C, a positive current collector unit 4B, and a negative current collector unit 5B. The battery cell 1Q differs from the battery cells 1 and 1A to 1H according to Embodiments 1 to 3 in that the battery cell 1Q includes a stacked electrode assembly 3C instead of the stacked electrode assemblies 3 and 3A.

[0153] Furthermore, the battery cell 1Q differs from the battery cells 1 and 1A to 1H according to Embodiments 1 to 3 in that the battery cell 1Q includes a positive current collector unit 4B and a negative current collector unit 5B instead of the positive current collector units 4 and 4A and the negative current collector units 5 and 5B. The battery cell 1Q differs from the battery cells 1 and 1A to 1H according to Embodiments 1 to 3 in that the battery cell 1Q does not include an insulating film 9.

[0154] Similar to the stacked electrode assembly 3, a constraining force (pressure) in the D1 direction is applied to the stacked electrode assembly 3C by a cover 2b and a main unit 2a. An electrolyte solution is injected into the outer casing 2.

[0155] The stacked electrode assembly 3C is a bipolar electrode assembly. The stacked electrode assembly 3C includes a plurality of bipolar electrodes 350 and a plurality of separators 360. In the stacked electrode assembly 3C, the bipolar electrodes 350 are stacked in the D1 direction via separators 360.

[0156] Each bipolar electrode 350 has a current collector foil 351, a positive electrode 352, and a negative electrode 353. The positive electrode 352 is formed on one surface of the current collector foil 351. The negative electrode 353 is formed on the other surface of the current collector foil 351. In this example, the positive electrode 352 is formed on the cover-side surface of the current collector foil 351. The positive electrode 352 is formed on the main unit-side surface of the current collector foil 351.

[0157] The positive current collector unit 4B and the negative current collector unit 5B function as current collector units for the stacked electrode assembly 3C. Specifically, the positive current collector unit 4B and the negative current collector unit 5B function as terminal electrodes of the stacked electrode assembly 3C.

[0158] The positive current collector unit 4B is stacked on the bipolar electrode 350 on the top side 25 in the D1 direction above the separator 360. Furthermore, the positive current collector unit 4B is in contact with the inner wall surface 251 of the top side 25. The negative current collector unit 5B is stacked on the bipolar electrode 350 on the bottom side 21 in the D1 direction above the separator 360. Furthermore, the negative current collector unit 5B is in contact with the inner wall surface 211 of the bottom side 21.

[0159] Specifically, the positive current collector unit 4B includes 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 surface 25. The negative electrode 483 is in contact with the other surface of the current collector foil 481. The negative electrode 483 of the positive current collector unit 4B and the positive electrode 352 of the bipolar electrode 350 adjacent to the positive current collector unit 4B are opposed to each other via the separator 360.

[0160] The negative current collector unit 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 surface 21. The positive electrode 582 is formed on the other surface of the current collector foil 581. The positive electrode 582 of the negative current collector unit 5B and the negative electrode 353 of the bipolar electrode 350 adjacent to the negative current collector unit 5B face each other via the separator 360.

[0161] As described above, the battery cell 1Q includes: (i) a stacked electrode assembly 3C in which negative electrodes 353 and positive electrodes 352 are alternately stacked in the D1 direction; (ii) a negative current collector unit 5B connected to a negative electrode 353; (iii) a positive current collector unit 4B connected to a positive electrode 352; (iv) and an outer case 2 that houses the stacked electrode assembly 3C, the negative current collector unit 5B, and the positive current collector unit 4B. The outer case 2 includes the main unit 2a and the cover 2b. The current collector foil 581 of the negative current collector unit 5B is located between the main unit 2a and the stacked electrode assembly 3C in the D1 direction and is electrically connected to the main unit 2a.The current collector foil 481 of the positive current collector unit 4B is located between the cover 2b and the stacked electrode assembly 3C in the D1 direction and is electrically connected to the cover 2b.

[0162] With such a configuration, the negative current collector unit 5B can allow the main unit 2a of the outer casing 2 to function as the negative terminal. The positive current collector unit 4B can allow the cover 2b of the outer casing 2 to function as the positive terminal.

[0163] Furthermore, the negative current collector unit 5B is connected to the main unit 2a via the current collector foil 581 located between the main unit 2a and the stacked electrode assembly 3C in the D1 direction. The positive current collector unit 4B is connected to the cover 2b via the current collector foil 481 located between the cover 2b and the stacked electrode assembly 3C in the D1 direction. Accordingly, the positive current collector unit 4B and the negative current collector unit 5B, which are separated from each other in the D1 direction, can be brought into contact with the outer casing 2.

[0164] Therefore, according to the battery cell 1Q, the volumetric efficiency can be increased compared to the battery cell configuration in which only one of the negative current collector unit and the positive current collector unit is in contact with the outer casing. [Embodiment 6]

[0165] The present embodiment will be described with reference to a battery cell having a stacked electrode assembly different from the stacked electrode assembly 3 according to Embodiment 1.

[0166] Fig. 16 is a diagram showing a battery cell 1R according to the present embodiment. As shown in Fig. 16, the battery cell 1R includes an outer casing 2, a stacked electrode assembly 3D, a positive current collector unit 4, a negative current collector unit 5, an insulating material 6, and an insulating film 9. The stacked electrode assembly 3D includes a plurality of electrode units 39.

[0167] The electrode units 39 are stacked in the D1 direction. The electrode units 39 are connected to the positive current collector unit 4 and the negative current collector unit 5. The insulating film 9 is located between the electrode unit 39 on the main unit 2a side and the negative current collector unit 5. Specifically, the insulating film 9 is located between the electrode unit 39 on the main unit 2a side and part 512 (see Fig. 2) the negative current collector unit 5.

[0168] Fig. 17 is a diagram showing the electrode unit 39. As in Fig. As shown in Figure 17, the electrode unit 39 includes a plurality of positive electrode current collector foils 391, a plurality of positive electrode layers 392, a plurality of separator layers 393, a plurality of negative electrode layers 394, and a plurality of negative electrode current collector foils 395. In the electrode unit 39, the current collector foil 391, the positive electrode layer 392, the separator layer 393, the negative electrode layer 394, and the current collector foil 395 are stacked in the D1 direction in the specified order. The separator layer 393 contains a solid electrolyte and a binder.

[0169] In this example, a current collector foil 398, which acts as a terminal of the electrode unit 39, is connected to two current collector foils 391. A current collector foil 399, which acts as a terminal of the electrode unit 39, is connected to a current collector foil 395. The current collector foil 398 is connected to the current collector foil 41 ( Fig. 16). The current collector foil 399 is connected to the current collector foil 51 ( Fig. 16).

[0170] The battery cell 1R having such a configuration offers the same advantages as the battery cell 1 according to Embodiment 1. In addition, the variations of Embodiment 1 described above are applicable to the battery cell 1G as appropriate.

[0171] Although embodiments of the present invention have been described above, the embodiments disclosed herein should be considered in all respects as exemplary and not restrictive. The scope of the present invention is defined by the appended claims. All changes which come within the meaning and range of equivalence of the appended claims are intended to be embraced within their scope. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2024-023400

[0001] JP 2005- 310 618 A [0003, 0004]< / variationen>

Claims

[1] Battery cell (1, 1A to 1H, 1P to 1R), comprising: an electrode assembly (3, 3A to 3D) in which positive electrodes (31, 352, 392) and negative electrodes (32, 353, 394) are alternately stacked in a first direction; a first current collector unit (4, 4A, 4B) connected to at least one of the positive electrodes (31, 352, 392); a second current collector unit (5, 5A, 5B) connected to at least one of the negative electrodes (32, 353, 394); and an outer casing (2, 2A) accommodating the electrode assembly (3, 3A to 3D), the first current collector unit (4, 4A, 4B) and the second current collector unit (5, 5A, 5B), wherein the outer housing (2, 2A) comprises a first housing body and a second housing body, at least a portion of the first current collector unit (4, 4A, 4B) is located between the first housing body and the electrode arrangement (3, 3A to 3D) in the first direction and is electrically connected to the first housing body, and at least a portion of the second current collector unit (5, 5A, 5B) is located between the second housing body and the electrode arrangement (3, 3A to 3D) in the first direction and is electrically connected to the second housing body. [2] Battery cell (1, 1A to 1H, 1P to 1R) according to claim 1, wherein the first housing body a first base connected to the at least one portion of the first current collector unit (4, 4A, 4B), and a first side wall extending from an outer periphery of the first base in a first orientation of the first direction, the first orientation pointing toward the electrode assembly (3, 3A to 3D), wherein the second housing body a second base opposite to the first base and connected to at least a portion of the second current collector unit (5, 5A, 5B), and a second side wall extending from an outer periphery of the second base in a second orientation opposite the first orientation, wherein the first side wall and the second side wall partially overlap, seen in a second direction perpendicular to the first direction. [3] Battery cell (1, 1A to 1H, 1P to 1R) according to claim 2, wherein an insulating material (6, 6A) is inserted between the first side wall and the second side wall. [4] Battery cell (1, 1A to 1H, 1P to 1R) according to claim 2 or 3, wherein the first current collector unit (4, 4A, 4B) comprises a plurality of first current collector foils (41, 41A) each connected to a different positive electrode of the positive electrodes (31, 352, 392), wherein the first current collector foils (41, 41A) each a first part (411) extending from the positive electrode (31, 352, 392) toward the first base, and a second part (412) which adjoins the first part (411) and extends parallel to the first base between the first base and the electrode arrangement (3, 3A to 3D), wherein the second part (412) is electrically connected to the first housing body and is opposite the negative electrode (32, 353, 394) in the first direction, and the second part (412) and the negative electrode (32, 353, 394) opposite the second part (412) in the first direction are insulated from each other. [5] Battery cell (1, 1A to 1H, 1P to 1R) according to claim 2 or 3, wherein the second current collector unit (5, 5A, 5B) comprises a plurality of second current collector foils (51, 51A) each connected to a different negative electrode of the negative electrodes (32, 353, 394), wherein the second current collector foils (51, 51A) each a first part (511) extending from the negative electrode (32, 353, 394) towards the second base, and a second part (512) which adjoins the first part (511) and extends parallel to the second base between the second base and the electrode arrangement (3, 3A to 3D), wherein the second part (512) is electrically connected to the second housing body and is opposite to the positive electrode (31, 352, 392) in the first direction, and the second part (512) and the positive electrode (31, 352, 392) opposite the second part (512) in the first direction are insulated from each other. [6] The battery cell (1G, 1R) according to claim 1, wherein the electrode assembly (3A, 3D) further comprises a separator layer (35, 393) between the positive electrode (31, 392) and the negative electrode (32, 394), the separator layer (35, 393) comprising a solid electrolyte. [7] The battery cell (1, 1A to 1H, 1P to 1R) according to claim 1, wherein one of the first case body and the second case body is a main unit (2a, 2c) of the outer case (2, 2A) and the other of the first case body and the second case body is a cover (2b, 2d) of the outer case (2, 2A). [8] Battery module (800), comprising a plurality of battery cells, including the battery cell (1, 1A to 1H, 1P to 1R) according to claim 1, wherein the plurality of battery cells (1, 1A to 1H, 1P to 1R) are stacked in the first direction. [9] A method for producing a battery cell, comprising: Assembling a battery cell (1, 1A to 1H, 1P to 1R) comprising: an electrode assembly (3, 3A to 3D) in which positive electrodes (31, 352, 392) and negative electrodes (32, 353, 394) are alternately stacked in a first direction; a first current collector unit (4, 4A, 4B) connected to at least one of the positive electrodes (31, 352, 392); and a second current collector unit (5, 5A, 5B) connected to at least one of the negative electrodes (32, 353, 394) such that the first current collector unit (4, 4A, 4B) is in contact with a first casing body of an outer casing (2, 2A) of the battery cell (1, 1A to 1H, 1P to 1R) in the first direction; Moving the first housing body and a second housing body of the outer housing (2, 2A) relative to each other so that the second current collector unit (5, 5A, 5B) is in contact with the second housing body in the first direction; and Attaching one of the first housing body and the second housing body to the other of the first housing body and the second housing body. [10] A method for producing a battery cell according to claim 9, wherein the first housing body a first base connected to the at least one portion of the first current collector unit (4, 4A, 4B), and a first side wall extending from an outer periphery of the first base in a first orientation of the first direction, the first orientation pointing toward the electrode assembly (3, 3A to 3D), wherein the second housing body a second base opposite to the first base and connected to at least a portion of the second current collector unit (5, 5A, 5B), and a second side wall extending from an outer periphery of the second base in a second orientation opposite the first orientation, wherein the first side wall and the second side wall partially overlap, viewed in a second direction perpendicular to the first direction, and the method for producing a battery cell further comprises introducing an insulating material (6, 6A) between the first side wall and the second side wall.

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