Battery module, laminated casing, and method for manufacturing battery cells

Abstract

The present invention provides a battery module, a laminated casing, and a method for manufacturing battery cells that can ensure insulation between the battery cell and the housing with a simple configuration. [Solution] The battery module comprises a plurality of battery cells stacked in the Z direction and a housing that houses the plurality of battery cells. Each battery cell comprises a battery body and a pair of laminated outer casings 30 that sandwich the battery body in the Z direction. The laminated outer casings 30 comprises an outer sheet 31 made of resin, an intermediate sheet 33 made of metal, and an inner sheet 32 ​​made of resin that sandwiches the intermediate sheet 33 together with the outer sheet 31. At least the ends of the pair of laminated outer casings 30 facing the housing, the outer sheet 31 and the inner sheet 32 ​​are provided extending toward the housing side from the intermediate sheet 33.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a battery module, a laminated exterior body, and a battery cell.

Background Art

[0002] Conventionally, there has been known a battery module having a battery cell in which a cell body composed of power generation elements is laminated with a laminated exterior body, and a plurality of the battery cells are stacked and housed in a housing (see, for example, Patent Document 1). In the battery module described in Patent Document 1, a battery cell (battery body) is laminated with a pair of laminated exterior bodies (laminated films). The laminated exterior body includes a sheet-shaped metal layer and a sheet-shaped insulating layer that covers both surfaces of the metal layer, and the battery cell is sandwiched and laminated between the pair of laminated exterior bodies. The end portion of the laminated exterior body is folded back, so that the metal layer at the outer edge of the laminated exterior body is suppressed from contacting the housing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the battery module of Patent Document 1, the laminated exterior body may be thermally deformed due to heat generation of the battery cell, and the shape of the bent portion at the end of the laminated exterior body may change. In Patent Document 1, since the metal layer is exposed at the outer edge of the laminated exterior body, when the shape of the bent portion changes, the metal layer exposed from the outer edge of the laminated exterior body may contact the housing, and there is a problem that insulation cannot be ensured. Furthermore, it is conceivable to separately provide a resin component to cover the metal layer along the outer edge of the laminate casing. However, in this case, it is necessary to provide a new resin component, which increases manufacturing costs and requires space for the resin component, thus increasing the weight of the battery module.

[0005] The present invention aims to provide a battery module, a laminated casing, and a method for manufacturing battery cells that can ensure insulation between the battery cell and the housing with a simple configuration. [Means for solving the problem]

[0006] The battery module of this disclosure has multiple battery cells arranged in a first direction, each laminated by sandwiching a battery body between a pair of laminated casings, and the multiple battery cells are housed in a housing. The laminated casing includes an outer sheet made of resin, an intermediate sheet made of metal, and an inner sheet made of resin, with the intermediate sheet laminated between the outer sheet and the inner sheet. At least at the ends of the laminated casing facing the housing, the outer sheet and the inner sheet extend toward the housing side beyond the intermediate sheet.

[0007] In this configuration, the metal intermediate sheet is not exposed from the edges (outer edges) of the laminated casing. Therefore, even if the edges (outer edges) of the laminated casing come into contact with the housing, a short circuit will not occur between the battery cells and the housing, and the performance of the battery module can be maintained. In addition, since there is no need to fold the edges of the laminated casing or to add separate resin components, manufacturing costs can be reduced compared to conventional designs, and the battery module can be made lighter and more compact. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view showing the schematic configuration of the battery module of the first embodiment. [Figure 2] A perspective view showing the schematic configuration of a battery cell according to the first embodiment. [Figure 3]An exploded perspective view of the battery cell of the first embodiment. [Figure 4] A cross-sectional perspective view showing the schematic configuration of the laminate exterior body of the first embodiment. [Figure 5] A diagram showing a manufacturing method for a battery module according to the first embodiment. [Figure 6] A perspective view showing an example of a mother roll equipped with a laminated outer casing according to the first embodiment, and a slit roll cut from the mother roll. [Figure 7] A diagram showing the positions of the first and second regions in the mother roll of the first embodiment. [Figure 8] A schematic diagram showing the crimping process of the laminated outer casing in the first embodiment. [Figure 9] A diagram illustrating a conventional manufacturing method for a liquid lithium battery module, as an example. [Figure 10] (A) is a schematic diagram showing the cross-sectional shape of the laminate exterior of the second embodiment, and (B) is an enlarged perspective view showing the portion of (A) indicated by the dashed line. [Figure 11] In the second embodiment, this is a schematic diagram showing the process of crimping a pair of laminate outer casings, where (A) shows the state before crimping and (B) shows the state after crimping. [Figure 12] A cross-sectional perspective view of the end of the laminate exterior of the third embodiment. [Figure 13] In the third embodiment, this is a schematic diagram showing the process of crimping a pair of laminate outer casings, where (A) shows the state before crimping and (B) shows the state after crimping. [Figure 14] A diagram showing the schematic configuration of a mother roll equipped with a laminated outer casing according to Modification 1. [Figure 15] A cross-sectional view showing the schematic configuration of the laminate exterior body according to Modification 2. [Figure 16] A cross-sectional view showing the schematic configuration of the laminate exterior body according to Modification 3. [Modes for carrying out the invention]

[0009] [First Embodiment] Hereinafter, a first embodiment of the present disclosure will be described. FIG. 1 is a perspective view showing a schematic configuration of the battery module 1 of the present embodiment. FIG. 2 is a perspective view showing a schematic configuration of one battery cell 20 of the battery module 1. FIG. 3 is an exploded perspective view of the battery cell 20. The battery module 1 includes a housing 10 and a plurality of battery cells 20 housed in the housing 10. These battery cells 20 are stacked along the Z direction (first direction) and housed in the housing 10.

[0010] As shown in FIG. 3, each battery cell 20 includes a battery body portion 21 and a pair of laminate exterior bodies 30 that sandwich the battery body portion 21 from the Z direction. The battery body portion 21 includes a power generation element 211 that constitutes an all-solid-state battery and electrode tabs (a positive electrode tab 212A and a negative electrode tab 212B). Although detailed illustration of the power generation element 211 is omitted, it is composed of a laminate of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. In the present embodiment, as shown in FIGS. 1 to 3, the positive electrode tab 212A is drawn out to the +Y side in the Y direction orthogonal to the Z direction, and the negative electrode tab 212B is drawn out to the -Y side in the Y direction. Also, the direction orthogonal to the Z direction and the Y direction is defined as the X direction.

[0011] The positive electrode layer includes a positive electrode current collector and a positive electrode active material layer. The positive electrode current collector is composed of, for example, a metal foil such as SUS (Steel Use Stainless), aluminum, nickel, iron, stainless steel, titanium, or copper. The positive electrode active material layer is laminated on at least one of the +Z side and -Z side surfaces of the positive electrode current collector. The positive electrode current collector is connected to the positive electrode tab 212A. The positive electrode active material layer is composed of, for example, a positive electrode active material, a sulfide solid electrolyte, a conductive assistant, a binder, and xylene. Examples of the positive electrode active material include lithium-transition metal composite oxides such as LiMn2O4, LiCoO2, LiNiO2, Li(Ni-Mn-Co)O2, and those in which a part of these transition metals is substituted with other elements, lithium-transition metal phosphate compounds, lithium-transition metal sulfate compounds, and the like. Here, an example in which the positive electrode active material layer uses a lithium compound is shown, but a battery using other metals may also be used.

[0012] The solid electrolyte layer is a layer disposed between the positive electrode active material layer and the negative electrode active material layer. The solid electrolyte layer contains a solid electrolyte as a main component, and examples of the solid electrolyte include those composed of a sulfide solid electrolyte, a binder, and xylene.

[0013] The negative electrode layer includes a negative electrode layer and a negative electrode current collector. The negative electrode layer is laminated on the solid electrolyte layer and is composed of, for example, carbon black as a negative electrode active material, a conductive metal, a binder, and NMP (N-methylpyrrolidone). Similar to the positive electrode current collector, the negative electrode current collector is formed of a metal foil such as SUS, aluminum, nickel, iron, stainless steel, titanium, or copper, for example. The negative electrode layer is laminated on at least one of the +Z side and the -Z side surfaces of the negative electrode current collector. The negative electrode current collector is connected to the negative electrode tab 212B.

[0014] In this embodiment, the battery body 21 as described above is sandwiched between a pair of laminate exterior bodies 30, and the ends of the laminate exterior bodies 30 are sealed, whereby the battery body 21 is laminated. FIG. 4 is a cross-sectional perspective view showing the schematic configuration of the laminate exterior body 30, and particularly shows a view in the vicinity of the +X side end facing the wall surface of the housing 10. As shown in FIG. 4, the laminate exterior body 30 is composed of an exterior sheet 31, an interior sheet 32, and an intermediate sheet 33 sandwiched between the exterior sheet 31 and the interior sheet 32. The outer sheet 31 and the inner sheet 32 ​​are insulating sheet materials made of resin. For example, in this embodiment, the outer sheet 31 is made of PET (polyethylene terephthalate), and the inner sheet 32 ​​is made of PP (polypropylene). On the other hand, the intermediate sheet 33 is a metal sheet, and is made of, for example, Al (aluminum).

[0015] Here, the laminated outer casing 30 comprises a first region 30A that includes a predetermined margin from the portion where the power generation element 211 is arranged, with respect to the X direction, and a second region 30B provided outside the first region 30A (on the ±X side). The first region 30A is composed of a three-layer laminate consisting of an outer sheet 31, an intermediate sheet 33, and an inner sheet 32. On the other hand, the second region 30B does not have an intermediate sheet 33 and is composed of a two-layer laminate of an exterior sheet 31 and an interior sheet 32. In other words, the laminated casing 30 has an outer sheet 31 and an inner sheet 32 ​​whose lengths in the X direction are longer than the length of the intermediate sheet 33 in the X direction, and extends outward from the ±X side ends of the intermediate sheet 33, that is, toward the wall side of the housing 10. In the pair of laminated casings 30, the first region 30A laminates the surface of the battery body 21. In the pair of laminated casings 30, the inner sheet 32 ​​of the margin portion of the first region 30A that does not come into contact with the battery body 21 and the inner sheet 32 ​​of the second region 30B are pressed together. As a result, the ends of the pair of laminated casings 30 are joined and the battery body 21 is sealed.

[0016] In this embodiment, as described above, a metal intermediate sheet 33 is not placed in the second region 30B. Therefore, the intermediate sheet 33 is not exposed from the outer edge of the laminated exterior 30. For this reason, in this embodiment, even if the outer edge of the laminated exterior 30 comes into contact with the housing 10, a short circuit does not occur, there is no need to provide a separate insulating resin member on the outer edge of the laminated exterior 30, nor is there a need to fold back the end of the laminated exterior 30 to move the outer edge away from the wall surface of the housing 10.

[0017] [Manufacturing of battery modules and battery cells] Figure 5 is a schematic diagram illustrating a method for manufacturing a battery module. When manufacturing the battery module 1 of this embodiment, as shown in Figure 5(A), a battery body 21 with electrode tabs (positive electrode tab 212A, negative electrode tab 212B) connected to a power generation element 211, and a pair of laminated casings 30 for laminating the battery body 21 are prepared.

[0018] Here, manufacturing individual laminated casings 30 to match the size of each battery cell 20 is inefficient in terms of production, and also inefficient in terms of transporting them from the factory that manufactures the laminated casings 30 to the assembly factory of the battery module 1. Therefore, the laminated casings 30 are usually manufactured as a mother roll that is larger in size than the individual battery cells 20.

[0019] Figure 6 shows an example of a mother roll 40 and a slit roll 41 cut from the mother roll 40. Figure 7 shows the positions of the first region 30A and the second region 30B in the mother roll 40. As shown in Figure 7, the mother roll 40 of this embodiment is a roll body wound from a sheet in which multiple sets of second region 30B, first region 30A, and second region 30B are arranged in the order of second region 30B, first region 30A, and second region 30B along the X direction. Such a mother roll 40 is cut between two adjacent sets of second region 30B in the X direction, that is, at the position shown by the dashed line (cut line C) in Figures 6 and 7. As a result, a slit roll 41 is obtained in which both ends in the X direction become second region 30B, and the first region 30A is positioned between the second region 30B. In this embodiment, a slit roll 41 is formed by slitting the mother roll 40, and a laminated outer casing 30 with dimensions matching the size of the battery cell 20 in the Y direction is cut from the slit roll 41.

[0020] Next, as shown in Figure 5(B), the battery body 21 is sandwiched and laminated between a pair of laminated casings 30. Figure 8 is a schematic diagram showing the crimping process of the laminated outer casing 30. The pair of laminated outer casings 30 are joined using, for example, a pressure jig 50 as shown in Figure 8. The pressurizing jig 50 includes a first pressurizing section 51 that pressurizes the first regions 30A of a pair of laminated outer casings 30 together, and a second pressurizing section 52 that pressurizes the second regions 30B together, and is positioned on both the ±Z sides of the battery cell 20. The second pressurizing section 52 protrudes more towards the opposing pressurizing jig 50 compared to the first pressurizing section 51. The protruding dimension of the second pressurizing section 52 is the same as the thickness of the intermediate sheet 33.

[0021] Furthermore, the pressurizing jig 50 only needs to be placed at the joints between the pair of laminated casings 30, and is not placed at the locations where the power generation element 211 is positioned. In other words, the pressurizing jig 50 is positioned corresponding to the margin portion of the first region 30A and the second region 30B of the laminated casing 30. The pressurizing jig 50 heats the margin portion of the first region 30A and the second region 30B, and applies pressure in the Z direction to press the pair of laminated casings 30 together.

[0022] After the above steps, as shown in Figure 5(C), multiple battery cells 20 are stacked in the Z direction, and as shown in Figure 5(D), the stacked battery cells 20 are housed in the housing 10. In this case, a gap of a predetermined distance (insulation distance) is provided between the ±X side ends of the laminated casing 30 of the battery cell 20 and the wall surface of the housing 10. In this embodiment, even if the outer edge of the laminated casing 30 comes into contact with the housing 10, the intermediate sheet 33 is not exposed from that outer edge as described above, so problems such as short circuits are suppressed.

[0023] (reference) Next, for reference, the manufacturing method of a conventional liquid lithium battery module (comparative example) will be explained using Figure 9. When manufacturing a battery module for a comparative example of a liquid lithium battery, first, as shown in Figure 9(A), an electrode stack 91 and a laminate sheet 92 are prepared. The electrode stack 91 is a laminate formed by stacking a positive electrode and a negative electrode. The positive electrode comprises a positive electrode active material layer and a positive electrode current collector foil, with the positive electrode current collector foil connected to the positive electrode tab. The negative electrode comprises a negative electrode active material layer and a negative electrode current collector foil, with the negative electrode current collector foil connected to the negative electrode tab. The laminate sheet 92, similar to this embodiment, comprises an insulating outer sheet, an insulating inner sheet, and a metallic intermediate sheet, but the intermediate sheet is sandwiched between the outer sheet and the inner sheet over the entire area of ​​the laminate sheet. In other words, a second region 30B, which consists only of the outer sheet and the inner sheet, as in this embodiment, is not provided.

[0024] In the comparative example battery module, as shown in Figure 9(B), each electrode stack 91 is laminated with a laminate sheet 92, and then the outer periphery of the laminate sheet is temporarily sealed. Then, as shown in Figure 9(C), the liquid electrolyte is injected into the internal sealing region sealed with the laminate sheet 92. After this, as shown in Figure 9(D), an aging process is performed to maintain the temperature at a predetermined level for a predetermined time, and then, as shown in Figure 9(E), the gas generated in the internal sealing region is removed.

[0025] After the above, as shown in Figure 9(F), the laminate sheet 92 is sealed, and the pair of opposing laminate sheets 92 are brought into close contact at their outer edges. Furthermore, in the comparative example battery module, the metal intermediate sheet is exposed at the outer edge of the laminate sheet 92. Therefore, as shown in Figure 9(G), the outer edge of the laminate sheet 92 is folded to conceal the outer edge of the laminate sheet 92. The battery cell 94 is then manufactured. Next, as shown in Figure 9(H), multiple battery cells 94 are stacked, and as shown in Figure 9(I), these battery cells 94 are housed in the housing 95.

[0026] The manufacturing method for the all-solid-state battery module 1 of this embodiment, shown in Figure 5, eliminates the need for the bending process of the laminate sheet 92 compared to the comparative example battery module shown in Figure 9. In particular, the all-solid-state battery module 1 of this embodiment also eliminates the need for the temporary sealing process of the laminate sheet 92, the liquid electrolyte injection process, the aging process, and the degassing process, thus enabling a significant reduction in the number of manufacturing steps and greatly lowering manufacturing costs.

[0027] [Effects of this embodiment] The battery module 1 of this embodiment comprises a housing 10 and a plurality of battery cells 20 housed in the housing 10. Each battery cell 20 includes a battery body 21 and a pair of laminated outer casings 30 that sandwich the battery body 21 in the Z direction. The laminated casing 30 includes an outer sheet 31 made of resin, an intermediate sheet 33 made of metal, and an inner sheet 32 ​​made of resin, with the intermediate sheet 33 sandwiched between the outer sheet 31 and the inner sheet 32 ​​in the Z direction. In a pair of laminated casings 30, the battery body 21 is laminated so that the inner sheets 32 face each other, and the battery body 21 is sealed by heating and pressurizing the ends of the laminated casing 30. The laminated casing 30 has a first region 30A where the outer sheet 31, intermediate sheet 33, and inner sheet 32 ​​are laminated, and a second region 30B where the intermediate sheet 33 is not provided and is composed of a laminate of the outer sheet 31 and the inner sheet 32, with the second region 30B located at least at the X direction end of the laminated casing 30. In other words, by positioning the second region 30B at the end of the laminated outer casing 30 facing the housing 10, the outer sheet 31 and the inner sheet 32 ​​extend further toward the housing 10 than the intermediate sheet 33.

[0028] As a result, the metal intermediate sheet 33 is not exposed from the outer edge of the laminated casing 30. Therefore, even if the outer edge of the laminated casing 30 comes into contact with the housing 10, a short circuit will not occur, and the performance of the battery cell 20 can be maintained. Furthermore, in this embodiment, when joining and sealing the second regions 30B of a pair of laminate outer casings 30, there is no metal intermediate sheet 33 in the second region 30B, thus shortening the time required for sealing. Furthermore, there is no need to separately provide a resin component at the end of the laminated casing 30 or to bend the end of the laminated casing 30, which allows for miniaturization and weight reduction of the battery cell 20.

[0029] [Second Embodiment] Next, a second embodiment will be described. In the first embodiment described above, an example was shown in which the second region 30B of the laminate exterior 30 is composed of a laminate formed by laminating a single layer exterior sheet 31 and a single layer interior sheet 32. In contrast, the second embodiment differs from the first embodiment in that the interior sheet 32 ​​in the second region 30B has a two-layer structure. In the following description, the same components are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0030] Figure 10(A) is a schematic diagram showing the cross-sectional shape of the laminate exterior 34 of the second embodiment, and Figure 10(B) is an enlarged perspective view showing an enlarged portion of the dashed line in Figure 10(A). This embodiment is a modification of the laminated casing 30 of the battery module 1 in the first embodiment, and the other configurations are the same as those of the first embodiment. The laminated exterior 34 of this embodiment includes a first region 30A and a second region 30B, similar to the first embodiment. The configuration of the first region 30A is the same as in the first embodiment, and is composed of a laminate of an exterior sheet 31, an intermediate sheet 33, and an interior sheet 32. On the other hand, in this embodiment, the laminated exterior 34 is double-layered in the second region 30B by folding back the interior sheet 32 ​​at its edge.

[0031] In the example shown in Figure 10, in the laminated exterior 34 located on the +Z side, the folded portion of the interior sheet 32 ​​(interior folded portion 32A) is located on the -Z side, and in the laminated exterior 34 located on the -Z side, the interior folded portion 32A is located on the +Z side. In other words, the interior sheet 32 ​​extends from the first region 30A to the second region 30B, from the intermediate sheet 33 to the exterior sheet 31, and the interior folded portion 32A, which is folded back at the edge of the laminated exterior 34, is folded onto the interior sheet 32.

[0032] The manufacturing of the battery cell 20 and battery module 1 using the laminated casing 34 of this embodiment is substantially the same as that of the first embodiment. Therefore, similar to the manufacturing method shown in Figure 5, after laminating the power generation element 211 with the laminated casing 34, the edges of the laminated casing 34 (the margin portion of the first region 30A and the second region 30B) are heated and pressurized using a pressurizing jig to bond them together.

[0033] Figure 11 is a schematic diagram showing the process of crimping a pair of laminate outer casings 34 in this embodiment, with Figure 11(A) showing the state before crimping and Figure 11(B) showing the state after crimping. In this embodiment, before the pair of laminated outer casings 34 are pressed together, the thickness of the inner sheet 32 ​​(dimension in the Z direction) is greater than the thickness of the intermediate sheet 33. Therefore, as shown in Figure 11(A), when the second region 30B is not pressed and the pair of laminated outer casings 34 are not joined, the thickness of the second region 30B is greater than the thickness of the first region 30A.

[0034] In this embodiment, when pressing the pair of laminate outer casings 34 together, a pressing jig 50A is used in which the first pressing section 53 corresponding to the first region 30A and the second pressing section 54 corresponding to the second region 30B are on the same plane, as shown in Figure 11. As described above, in this embodiment, before the pair of laminate outer casings 34 are pressed together, the thickness of the second region 30B is greater than the thickness of the first region 30A, so a gap is created between the opposing interior sheets 32 in the first region 30A. Then, by heating the pair of laminated outer casings 34 using the pressurizing jig 50A and applying pressure in the Z direction, a stronger pressure is applied to the second region 30B compared to the first region 30A. As a result, the interior sheet 32 ​​in the second region 30B is compressed, and as shown in Figure 11(B), the thickness of the first region 30A and the second region 30B become the same.

[0035] [Effects of this embodiment] The battery module of this embodiment can achieve the same effects as the first embodiment described above, and also achieves the following effects. In this embodiment, instead of providing an intermediate sheet 33 in the second region 30B, the interior sheet 32 ​​is configured in multiple layers (two layers in this embodiment), and the thickness of the first region 30A and the second region 30B are the same. Therefore, as a pressure jig 50A used when joining the second regions 30B of a pair of laminate exteriors 34, a jig can be used in which the first pressure section 53 corresponding to the first region 30A and the second pressure section 54 corresponding to the second region 30B are on the same plane. Compared to a jig in which a step is provided between the first and second pressure sections, such a pressure jig 50A has a simpler structure and is easier to position.

[0036] Furthermore, in this embodiment, the thickness of the second region 30B before sealing the pair of laminate outer casings 34 together is greater than that of the first region 30A, and the thickness of the second region 30B after sealing becomes the same as the thickness of the first region 30A. This allows the second regions 30B of the pair of laminate outer casings 34 to be pressed together with greater pressure, thereby improving airtightness and sealing strength. Consequently, the durability of the power generation element 211 against expansion and contraction can be increased. Furthermore, after sealing, the first region 30A and the second region 30B have the same thickness, making it possible to manufacture a battery cell 20 that can suppress snagging due to steps or other unevenness.

[0037] [Third Embodiment] Next, a third embodiment will be described. In the second embodiment described above, a configuration was shown in which the interior sheet 32 ​​is folded back and laminated in a double layer in the second region 30B of the laminate exterior 34. In contrast, the third embodiment differs from the first and second embodiments in that the exterior sheet 31 has a two-layer structure in the second region 30B.

[0038] Figure 12 is a cross-sectional perspective view of the end of the laminate exterior 35 of the third embodiment. This embodiment is a modification of the laminated casing 30 of the battery module 1 in the first embodiment, and the other configurations are the same as those of the first embodiment. The laminated exterior 35 of this embodiment includes a first region 30A and a second region 30B, similar to the first embodiment. The configuration of the first region 30A is the same as in the first embodiment, and is composed of a laminate of an exterior sheet 31, an intermediate sheet 33, and an interior sheet 32. On the other hand, in this embodiment, the laminated outer casing 35 is double-layered in the second region 30B by folding back the outer sheet 31 at its edge.

[0039] In the example shown in Figure 12, in the laminated outer casing 35 located on the +Z side, the folded outer casing portion 31A of the outer sheet 31 is folded back on the +Z side, and in the laminated outer casing 35 located on the -Z side, the folded outer casing portion 31A is located on the -Z side. In other words, the outer sheet 31 extends from the first region 30A to the second region 30B, from the intermediate sheet 33 to the interior sheet 32, and the folded outer casing portion 31A, which is folded back at the edge of the laminated outer casing 35, is folded and laminated on the outer sheet 31.

[0040] The manufacturing of the battery cell 20 and battery module 1 using the laminated casing 35 of this embodiment is substantially the same as that of the first embodiment. Therefore, similar to the manufacturing method shown in Figure 5, after laminating the power generation element 211 with the laminated casing 35, the edges of the laminated casing 35 (the margin portion of the first region 30A and the second region 30B) are heated and pressurized using a pressurizing jig to bond them together.

[0041] Figure 13 is a schematic diagram showing the process of crimping a pair of laminate outer casings 35 in this embodiment, where (A) shows the state before crimping and (B) shows the state after crimping. In this embodiment, when pressing the pair of laminated outer casings 35 together, a pressing jig 50A is used in which the first pressing section 53 corresponding to the first region 30A and the second pressing section 54 corresponding to the second region 30B are on the same plane, as shown in Figure 13. In other words, the pair of laminated outer casings 35 are pressed together using a pressing jig 50A similar to that in the second embodiment.

[0042] Furthermore, in this embodiment, the thickness (dimension in the Z direction) of the outer sheet 31 is greater than the thickness of the intermediate sheet 33. Therefore, when the second region 30B is not pressurized and the pair of laminate outer bodies 35 are not joined, the thickness of the second region 30B is greater than the thickness of the first region 30A. Therefore, in the pre-pressurized state, a gap is created between the outer sheet 31 and the pressurizing jig 50A in the first region 30A. By heating the pair of laminate outer casings 35 using the pressurizing jig 50A and applying pressure in the Z direction, a stronger pressure is applied to the second region 30B compared to the first region 30A. As a result, the outer sheet 31 in the second region 30B is compressed, and as shown in Figure 13, the thickness of the first region 30A and the second region 30B become the same.

[0043] [Effects of this embodiment] The battery module of this embodiment can achieve the same effects and advantages as the second embodiment described above. In this embodiment, the laminated outer casing 35 does not have an intermediate sheet 33 in the second region 30B. Instead, the outer casing sheet 31 is made up of multiple layers (two layers in this embodiment), and the thickness of the first region 30A and the second region 30B are the same. Therefore, similar to the second embodiment, a pressurizing jig 50A can be used when joining the second regions 30B of a pair of laminate exteriors 34, in which the first pressurizing section 53 corresponding to the first region 30A and the second pressurizing section 54 corresponding to the second region 30B are on the same plane. Compared to a jig in which a step is provided between the first pressurizing section and the second pressurizing section, such a pressurizing jig 50A has a simpler structure and is easier to arrange.

[0044] Furthermore, in this embodiment, the thickness of the second region 30B before sealing the pair of laminate outer casings 35 together is greater than that of the first region 30A, and the thickness of the second region 30B after sealing becomes the same as the thickness of the first region 30A. This allows the second regions 30B of the pair of laminate outer casings 35 to be pressed together with greater pressure, thereby improving airtightness and sealing strength. Consequently, the durability of the power generation element 211 against expansion and contraction can be increased. Furthermore, after sealing, the first region 30A and the second region 30B have the same thickness, making it possible to manufacture a battery cell 20 that can suppress snagging due to steps or other unevenness.

[0045] [Differentiation] The present invention is not limited to the embodiments described above, but also includes the following modifications to the extent that the objectives of the present invention can be achieved.

[0046] [Example 1] In the above embodiment, an example was shown in which a second region 30B is provided in the X direction of the laminated outer casings 30, 34, and 35, in which no intermediate sheet 33 is placed at the end. In contrast, the second region 30B may be provided in the Y direction of the laminated outer casings 30, 34, and 35, that is, in the direction in which the electrode tabs (positive electrode tab 212A, negative electrode tab 212B) are pulled out. This makes it possible to suppress short circuits of the battery cell 20 even if a metal member such as the housing 10 comes into contact with it in the Y direction.

[0047] Figure 14 shows the mother roll 40A for obtaining the laminated outer casing according to Modification 1. As shown in Figure 14, the mother roll 40A has alternating first regions 30A and second regions 30B in the X and Y directions, respectively. When using such a mother roll 40A, each laminated outer casing can be cut out by cutting the mother roll 40A along the cut line C shown by the dashed line in Figure 14, that is, along the center position of each second region 30B.

[0048] [Differentiation 2] In the second embodiment, the interior sheet 32 ​​is exemplified as having an interior folded portion 32A that is folded back on the opposite side from the exterior sheet 31 at the edge of the laminated exterior body 34 and folded onto the interior sheet 32, but the embodiment is not limited to this. Figures 15(A) and 15(B) are cross-sectional views showing a laminated exterior according to Modification 2. For example, as shown in the laminated exterior 36A in Figure 15(A), the interior sheet 32 ​​may be folded so that the interior folded portion 32A is folded back towards the exterior sheet 31 at the edge of the laminated exterior 36A and sandwiched between the exterior sheet 31 and the interior sheet 32.

[0049] Alternatively, as shown in Figure 15(B), a resin layer 32B made of the same material as the interior sheet 32 ​​may be laminated on the interior sheet 32. The resin layer 32B may be placed on the opposite side of the interior sheet 32 ​​from the exterior sheet 31, as shown in Figure 15(B), or it may be placed between the interior sheet 32 ​​and the exterior sheet 31.

[0050] [Difference 3] The same applies to the outer folded portion 31A in the third embodiment. Figures 16(A) and 16(B) are cross-sectional views showing a laminated exterior according to Modification 3. For example, as shown in Figure 16(A), the outer sheet 31 may be folded back towards the interior sheet 32 ​​at the edge of the laminated outer body 37A, so that the outer folded portion 31A is positioned between the outer sheet 31 and the interior sheet 32. Alternatively, as shown in Figure 16(B), a resin layer 31B made of the same material as the outer sheet 31 may be laminated on the outer sheet 31.

[0051] [Differentiation Example 4] In the above embodiment, a solid-state battery was exemplified as the battery module 1, but other batteries such as liquid lithium batteries may also be used. This can be applied to any battery in which the battery body, including the power generation element, is laminated with a laminate outer casing. [Explanation of Symbols]

[0052] 1...Battery module, 10...Housing, 20...Battery cell, 21...Battery main body, 30, 34, 35, 36A, 36B, 37A, 37B...Laminated outer casing, 30A...First region, 30B...Second region, 31...Outer sheet, 31A...Outer folded section, 32...Inner sheet, 32A...Inner folded section, 33...Intermediate sheet, 211...Power generation element, 212A...Positive electrode tab, 212B...Negative electrode tab.

Claims

1. Multiple battery cells stacked in the first direction, It comprises a housing that accommodates a plurality of the aforementioned battery cells, The battery cell includes a battery body and a pair of laminated outer casings that sandwich the battery body in a first direction. The laminated exterior comprises an exterior sheet made of resin, an intermediate sheet made of metal, and an interior sheet made of resin that sandwiches the intermediate sheet together with the exterior sheet, and a pair of the laminated exteriors are laminated with the interior sheets facing each other and sandwiching the battery cell. At least at the end of the laminated exterior body facing the housing, the exterior sheet and the interior sheet extend toward the housing side from the intermediate sheet. Battery module.

2. At the aforementioned end, multiple layers of the interior sheet are provided, and the thickness at the end is the same as the thickness of the portion where the exterior sheet, the intermediate sheet, and the interior sheet are laminated. The battery module according to claim 1.

3. At the aforementioned end, multiple layers of the exterior sheet are provided, and the thickness at the end is the same as the thickness of the portion where the exterior sheet, the intermediate sheet, and the interior sheet are laminated. The battery module according to claim 1.

4. A laminated casing for laminating the battery body, Exterior sheet made of resin, An intermediate sheet made of metal, It includes an interior sheet made of resin that sandwiches the intermediate sheet together with the exterior sheet, At the end of the laminate exterior, the exterior sheet and the interior sheet extend outward from the intermediate sheet. Laminated exterior.

5. At the aforementioned end, multiple layers of the interior sheet are provided, and the thickness at the end is the same as the thickness of the portion where the exterior sheet, the intermediate sheet, and the interior sheet are laminated. The laminated exterior body according to claim 4.

6. At the aforementioned end, multiple layers of the exterior sheet are provided, and the thickness at the end is the same as the thickness of the portion where the exterior sheet, the intermediate sheet, and the interior sheet are laminated. The laminated exterior body according to claim 4.

7. A method for manufacturing a battery cell in which the battery body is laminated with a laminate outer casing, The laminate exterior body includes an exterior sheet made of resin, an intermediate sheet made of metal, and an interior sheet made of resin that sandwiches the intermediate sheet together with the exterior sheet, wherein at the end of the laminate exterior body, the exterior sheet and the interior sheet extend outward from the intermediate sheet. The battery body is sandwiched between the pair of laminated outer casings so that the interior sheets face each other. The ends of the laminated outer casing are heated and pressurized to join and seal the opposing inner sheets. A method for manufacturing battery cells.

8. Multiple layers of the interior sheet are provided at the end, and the thickness of the end before sealing the end of the pair of laminated exterior bodies is greater than the portion where the exterior sheet, the intermediate sheet, and the interior sheet are laminated. The ends of the pair of laminated outer casings are heated and pressurized to make the thickness of the ends the same as the thickness of the portion where the outer sheet, the intermediate sheet, and the interior sheet are laminated. A method for manufacturing a battery cell according to claim 7.

9. Multiple layers of the outer sheet are provided at the end, and the thickness of the end before sealing the end of the pair of laminate outer bodies is greater than the portion where the outer sheet, the intermediate sheet, and the interior sheet are laminated. The ends of the pair of laminated outer casings are heated and pressurized to make the thickness of the ends the same as the thickness of the portion where the outer sheet, the intermediate sheet, and the interior sheet are laminated. A method for manufacturing a battery cell according to claim 7.

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