Battery cell, battery module, and method for manufacturing battery cell

Abstract

A battery cell (100) comprises a battery element (110), an exterior member (120), and an adhesive (130). The exterior member (120) comprises an accommodation portion (122) that accommodates the battery element (110), and an extension portion (124) that is drawn out from a peripheral edge portion (123) of the accommodation portion (122) positioned at least partially around the battery element (110). The adhesive (130) bonds the accommodation portion (122) and the extension portion (124) to each other in a state in which the extension portion (124) is at least partially bent toward the accommodation portion (122). The adhesive (130) and the peripheral edge portion (123) are separated from each other.

Description

Battery cell, battery module, and method of manufacturing the battery cell

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

[0002] In recent years, various types of battery cells have been developed. A battery cell includes a battery element and an exterior material that seals the battery element.

[0003] Patent Document 1 describes a secondary battery. The secondary battery includes a battery element and an exterior material that houses the battery element. The exterior material has an enclosure portion that encases the battery element and a joint piece portion that joins the peripheral edge of the exterior material. The joint piece portion is folded multiple times. The enclosure portion and the joint piece portion are bonded to each other via an adhesive.

[0004] Patent Document 2 describes a battery. The battery includes a power-generating cell and a covering member that covers the power-generating cell. The covering member has a base that defines a recess in which the power-generating cell is disposed, and a lid that covers the recess when the power-generating cell is disposed in the recess. The lid includes an extension that extends outward from the outer edge of the base. The extension and the outer edge of the base are bonded to each other with the extension bent toward the outer edge of the base.

[0005] Japanese Patent Application Laid-Open No. 2002-237279 Japanese Patent Application Laid-Open No. 2002-324524

[0006] The exterior material of the battery cell may have a housing portion that houses the battery element and an extension portion that is drawn out from a peripheral portion of the housing portion that is positioned around the battery element. The extension portion may be at least partially folded toward the housing portion. With the extension portion at least partially folded toward the housing portion, the housing portion and the extension portion may be bonded to each other with an adhesive. When the housing portion and the extension portion are bonded to each other, it may be necessary to reduce the area occupied by the battery cell and improve the dimensional accuracy of the battery cell.

[0007] An example of an object of the present invention is to achieve a reduction in the area occupied by the battery cell and an improvement in the dimensional accuracy of the battery cell. Other objects of the present invention will become apparent from the description of this specification.

[0008] One aspect of the present invention is as follows: 1. A battery cell comprising: a battery element; an exterior material having a housing portion that houses the battery element and an extending portion drawn out from a peripheral portion of the housing portion that is at least partially located around the battery element; and an adhesive that bonds the housing portion and the extending portion to each other in a state where the extending portion is at least partially folded toward the housing portion, wherein the adhesive and the peripheral portion are spaced apart. 2. The battery cell described in 1., wherein the extending portion includes a first portion folded toward the housing portion and a second portion folded toward between the housing portion and the first portion. 3. The battery cell described in 1. or 2., wherein the adhesive bonds the housing portion and the extending portion to each other in at least one of a state where the extending portion is folded at least partially non-perpendicular to a direction connecting the battery element and the peripheral portion or a state where the extending portion is at least partially rolled up. 4. The battery cell according to any one of 1. to 3., wherein the exterior material defines an opening that at least partially exposes the adhesive from between the housing portion and the extension portion, and the adhesive does not protrude beyond the opening. 5. The battery cell according to any one of 1. to 4., wherein the adhesive extends along the housing portion. 6. The battery cell according to any one of 1. to 5., wherein the adhesive at least partially contains a photocurable adhesive. 7. The battery cell according to any one of 1. to 5., wherein the adhesive at least partially contains a thermoplastic adhesive. 8. A battery module comprising the battery cell according to any one of 1. to 7., and a housing that houses the battery cell. 9. A method for manufacturing a battery cell, comprising: a step of adhering an accommodation portion of an exterior material that accommodates a battery element and an extension portion that is drawn out from a peripheral portion of the accommodation portion of the exterior material that is at least partially located around the battery element with an adhesive, with the extension portion being at least partially folded toward the accommodation portion; wherein the step of adhering the accommodation portion and the extension portion to each other includes a step of adhering the accommodation portion and the extension portion to each other with the adhesive, with the adhesive and the peripheral portion spaced apart from each other.

[0009] According to the above aspects of the present invention, it is possible to reduce the area occupied by the battery cells and improve the dimensional accuracy of the battery cells.

[0010] 1. A perspective view of a battery module according to an embodiment. FIG. 2. A perspective view of a battery module according to an embodiment with a module housing removed. FIG. 3. A cross-sectional view of the battery module according to an embodiment with a module housing removed. FIG. 4. A cross-sectional view of the battery module according to an embodiment with a module housing removed. FIG. 5. A cross-sectional view of the battery module according to an embodiment with a module housing removed. FIG. 6. A cross-sectional view of the battery module according to an embodiment with a module housing removed.

[0011] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and descriptions thereof will be omitted as appropriate.

[0012] Fig. 1 is a perspective view of a battery module 10 according to an embodiment. Fig. 2 is a perspective view of the battery module 10 according to an embodiment with a module housing 300 removed. Fig. 3 is a cross-sectional view taken along line AA in Fig. 1.

[0013] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the front-to-rear direction of the battery module 10. The Y direction is one of the directions perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery module 10. The Z direction is a direction perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery module 10. The arrow pointing to the X direction, the arrow pointing to the Y direction, and the arrow pointing to the Z direction indicate the rear, right, and up directions of the battery module 10, respectively. In FIG. 3, the white circle with an X indicating the X direction indicates that the tip of the arrow indicating the X direction is pointing into the paper. Hereinafter, as necessary, the tip side of the arrow indicating the X direction will be referred to as the +X side, the opposite side of the tip of the arrow indicating the X direction will be referred to as the -X side, the tip side of the arrow indicating the Y direction will be referred to as the +Y side, the opposite side of the tip of the arrow indicating the Y direction will be referred to as the -Y side, the tip side of the arrow indicating the Z direction will be referred to as the +Z side, and the opposite side of the tip of the arrow indicating the Z direction will be referred to as the -Z side. The relationship between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery module 10 is not limited to the above example.

[0014] As shown in FIGS. 1 to 3, a battery module 10 according to the embodiment includes a plurality of battery cells 100, a plurality of compression pads 200, and a module housing 300.

[0015] As shown in FIG. 3 , the multiple battery cells 100 and the multiple compression pads 200 are stacked alternately in the Y direction. Each compression pad 200 is disposed between adjacent battery cells 100 in the Y direction. Hereinafter, unless otherwise specified, a stack of battery cells 100 refers to the multiple battery cells 100 and the multiple compression pads 200 stacked alternately in the Y direction. As shown in FIGS. 1 to 3 , the X-direction dimension of each battery cell 100 is the longitudinal dimension of each battery cell 100. As shown in FIGS. 1 to 3 , the Z-direction dimension of each battery cell 100 is the lateral dimension of each battery cell 100. As shown in FIGS. 1 to 3 , the Y-direction dimension of each battery cell 100 is the thickness dimension of each battery cell 100. The shape of each battery cell 100 is not limited to this example.

[0016] As shown in FIGS. 1 to 3, each battery cell 100 includes a battery element 110 , an exterior material 120 , a positive terminal 142 , and a negative terminal 144 .

[0017] In FIG. 3 , the battery element 110 of the battery cell 100 located at the extreme end on the +Y side is illustrated by a dashed line. In one example, the battery element 110 includes multiple positive electrodes and multiple negative electrodes (not shown) stacked alternately in the Y direction, and a separator (not shown) located between adjacent positive electrodes and negative electrodes in the Y direction. The battery element 110 according to the embodiment has a substantially rectangular parallelepiped shape having a pair of main surfaces opposite each other in the Y direction, a pair of side surfaces opposite each other in the X direction, and another pair of side surfaces opposite each other in the Z direction. The pair of main surfaces opposite each other in the Y direction are substantially rectangular in shape, with a pair of long sides extending in the X direction and a pair of short sides extending in the Z direction. The pair of side surfaces opposite each other in the X direction are substantially rectangular in shape, with a pair of long sides extending in the Z direction and a pair of short sides extending in the Y direction. The other pair of side surfaces opposite each other in the Z direction are substantially rectangular in shape, with a pair of long sides extending in the X direction and a pair of short sides extending in the Y direction. The area of ​​each main surface of the battery element 110 is larger than the area of ​​any of the four side surfaces of the battery element 110. However, the shape of the battery element 110 is not limited to this example.

[0018] The exterior material 120 seals the battery element 110 and an electrolyte solution (not shown). As shown in FIG. 3, the exterior material 120 includes a first exterior material portion 120a and a second exterior material portion 120b. The first exterior material portion 120a and the second exterior material portion 120b are, for example, laminate films including a metal layer such as an aluminum layer and an insulating layer such as a resin layer covering both sides of the metal layer. The first exterior material portion 120a covers the +Y-side main surface of the battery element 110 and the +Y-side portion of the side surface surrounding the battery element 110 in the Y direction. The second exterior material portion 120b covers the −Y-side main surface of the battery element 110 and the −Y-side portion of the side surface surrounding the battery element 110 in the Y direction. In the embodiment, the first exterior material portion 120a and the second exterior material portion 120b are two sheets of exterior material joined together by a joining method such as heat fusion around the periphery in the Y direction of the battery element 110. However, the exterior material 120 may be a single sheet of exterior material folded back on one of the +Z side and the −Z side of the battery element 110. When the exterior material 120 is a single sheet of exterior material folded back on one of the +Z side and the −Z side of the battery element 110, the exterior materials 120 are joined together by a joining method such as heat fusion around the periphery in the Y direction of the battery element 110, excluding that one of the +Z side and the −Z side of the battery element 110.

[0019] Unless otherwise specified, the first exterior material portion 120a and the second exterior material portion 120b of the embodiment will be described as two exterior materials joined together by a joining method such as heat fusion around the Y-direction periphery of the battery element 110.

[0020] As shown in FIG. 3, the first and second exterior material portions 120a and 120b include a storage portion 122 and a pair of extension portions 124.

[0021] 3 , the housing portion 122 houses the battery element 110. The first exterior material portion 120a in the housing portion 122 covers the +Y side main surface of the battery element 110 and the +Y side portion of the side surface around the Y direction of the battery element 110. The second exterior material portion 120b in the housing portion 122 covers the −Y side main surface of the battery element 110 and the −Y side portion of the side surface around the Y direction of the battery element 110.

[0022] As shown in FIG. 3 , the pair of extension portions 124 are located on both sides of the housing portion 122 in the Z direction. Each extension portion 124 is drawn out from a peripheral portion 123 that is located at least partially around the Y direction periphery of the battery element 110 of the housing portion 122. As shown in FIG. 3 , the extension portion 124 on the +Z side is drawn out from the peripheral portion 123 located on the +Z side of the battery element 110. As shown in FIG. 3 , the extension portion 124 on the −Z side is drawn out from the peripheral portion 123 located on the −Z side of the battery element 110. The first exterior material portion 120a and the second exterior material portion 120b are joined to each other by a joining method such as heat fusion around the Y direction periphery of the battery element 110, including the extension portions 124. Therefore, the exterior material 120, including the pair of extension portions 124, seals the Y direction periphery of the battery element 110.

[0023] The positive electrode terminal 142 is electrically connected to the positive electrode of the battery element 110. The positive electrode terminal 142 is at least partially drawn out from between the first exterior material portion 120a and the second exterior material portion 120b on one of both sides in the X direction of the exterior material 120. The negative electrode terminal 144 is electrically connected to the negative electrode of the battery element 110. The negative electrode terminal 144 is at least partially drawn out from between the first exterior material portion 120a and the second exterior material portion 120b on the other side of the exterior material 120 in the X direction.

[0024] Each battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. An all-solid-state battery does not contain an electrolytic solution. Unless otherwise specified, the following description will be given assuming that each battery cell 100 is a battery cell containing an electrolytic solution.

[0025] The multiple battery cells 100 are electrically connected in a combination of series and parallel connections. Specifically, cell groups including at least two battery cells 100 adjacent to each other in the Y direction and connected in parallel are stacked in the Y direction and connected in series. As shown in FIG. 2 , a terminal group 140 including a positive terminal 142 of a battery cell 100 in one cell group connected in parallel and a negative terminal 144 of a battery cell 100 in another cell group connected in parallel is located on the −X side of the stack of battery cells 100. The positive terminal 142 and the negative terminal 144 in the terminal group 140 are electrically connected to each other by a joining method such as laser welding. A terminal group 140 is also located on the +X side of the stack of battery cells 100. Thus, multiple cell groups are connected in series from a cell group located at one end of the stack of battery cells 100 in the Y direction to a cell group located at the other end of the stack of battery cells 100 in the Y direction.

[0026] The electrical connection of the plurality of battery cells 100 is not limited to the above example. For example, the cell group may include three or more battery cells 100 connected in parallel. Alternatively, a stack of battery cells 100 may be formed by connecting single battery cells 100 in series.

[0027] 1 and 3, the module housing 300 includes a first plate 310, a second plate 320, a third plate 330, a fourth plate 340, a fifth plate 350, and a sixth plate 360. Each plate is made of a conductor such as a metal.

[0028] As shown in FIGS. 1 and 2, the first plate 310 covers the −X side portion of the stack of battery cells 100. As shown in FIGS. 1 and 2, the second plate 320 covers the +X side portion of the stack of battery cells 100. As shown in FIGS. 1 to 3, the third plate 330 covers the −Y side portion of the stack of battery cells 100. As shown in FIGS. 1 to 3, the fourth plate 340 covers the +Y side portion of the stack of battery cells 100. The fifth plate 350 covers the −Z side portion of the stack of battery cells 100, with the thermally conductive adhesive 352 positioned between the stack of battery cells 100 and the fifth plate 350. The thermally conductive adhesive 352 allows heat generated from the stack of battery cells 100 to dissipate toward the fifth plate 350. The sixth plate 360 ​​covers the +Z side portion of the stack of battery cells 100, with the structural adhesive 362 positioned between the stack of battery cells 100 and the sixth plate 360. The structural adhesive 362 bonds the stack of battery cells 100 and the sixth plate 360 ​​to each other. The thermal conductivity of the thermally conductive adhesive 352 is greater than the thermal conductivity of the structural adhesive 362. Therefore, heat generated from the stack of battery cells 100 can be more easily dissipated toward the fifth plate 350 than toward the sixth plate 360.

[0029] In the embodiment, the stack of battery cells 100 is compressed in the Y direction by the third plate 330 and the fourth plate 340. In the embodiment, the stack of battery cells 100 is compressed in the Z direction by the fifth plate 350 and the sixth plate 360.

[0030] FIG. 4 is an enlarged view of a portion of the battery cell 100 according to the embodiment shown in FIG.

[0031] The +Z side end of the battery cell 100 will be described using Figure 4. The -Z side end of the battery cell 100 is similar to the +Z side end of the battery cell 100, except that the +Z side end of the battery cell 100 and the -Z side end of the battery cell 100 are approximately symmetrical.

[0032] As shown in Fig. 4, the extension portion 124 is at least partially bent toward the housing portion 122. Specifically, the extension portion 124 includes an outer extension portion 124a and an inner extension portion 124b. As shown in Fig. 4, the outer extension portion 124a is bent toward the housing portion 122. As shown in Fig. 4, the inner extension portion 124b is bent toward between the housing portion 122 and the outer extension portion 124a.

[0033] In the embodiment, compared to when the inward extending portion 124b is not bent, the inward extending portion 124b can be prevented from protruding in a direction perpendicular to the X direction, for example, in the Y direction or the Z direction. Therefore, compared to when the inward extending portion 124b is not bent, the area occupied by the battery cells 100 in the direction perpendicular to the X direction can be reduced, for example, the area occupied by the stack of battery cells 100 in the Y direction or the Z direction can be reduced. Reducing the area occupied by the battery cells 100 in the direction perpendicular to the X direction creates a space for the stack of battery cells 100 relative to the internal space of the module housing 300, making it easier to comply with dimensional standards and other specifications for the battery module 10. Furthermore, compared to when the inward extending portion 124b is not bent, the dimensional accuracy of the stack of battery cells 100 in the direction perpendicular to the X direction can be improved, for example, the dimensional accuracy of the stack of battery cells 100 in the Y direction or the Z direction can be improved.

[0034] Furthermore, in the embodiment, compared to when the inner extending portion 124b is not bent, it is possible to improve the insulation between the conductor, such as metal foil, exposed from the tip of the inner extending portion 124b and the conductor present around the extending portion 124. For example, at the end on the +Z side of the battery cell 100, it is possible to improve the insulation between the conductor exposed from the tip of the inner extending portion 124b and the sixth plate 360.

[0035] 4, adhesive 130 is at least partially positioned between the -Y side portion of storage portion 122 and inner extending portion 124b. Adhesive 130 bonds the -Y side portion of storage portion 122 and inner extending portion 124b together. Therefore, the bent shape of extending portion 124 is fixed by adhesive 130.

[0036] As shown in FIG. 4 , the peripheral portion 123 and the +Y-side end of the adhesive 130 are spaced apart from each other. The adhesive 130 may be more difficult to harden closer to the peripheral portion 123. Therefore, in the embodiment, the adhesive 130 can be more easily hardened as a whole, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other. The more easily the adhesive 130 hardens, the more likely it is that the folded shape of the extension portion 124 will return to its original, unfolded shape. Therefore, in the embodiment, the area occupied by the battery cell 100 in the direction perpendicular to the X direction can be reduced, and the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction can be improved, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other. By improving the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction, the dimensional difference between the plurality of battery cells 100 can be reduced.

[0037] In the embodiment, the adhesive 130 extends continuously over substantially the entire X direction of the storage portion 122. For example, the adhesive 130 extends continuously in the X direction over 80% or more, preferably 90% or more, and more preferably 100% of the X direction dimension of the storage portion 122. If the folded shape of the extension portion 124 were fixed by a plurality of tapes spaced apart along the X direction instead of the adhesive 130, the portions of the extension portion 124 not fixed by the tapes might extend in a direction perpendicular to the X direction. However, in the embodiment, the adhesive 130 extends in the X direction, so that the storage portion 122 and the extension portion 124 can be continuously bonded to each other in the X direction. Therefore, in the embodiment, compared to when the folded shape of the extension portion 124 is fixed by a plurality of tapes spaced apart along the X direction, the area occupied by the battery cell 100 in the direction perpendicular to the X direction can be reduced and the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction can be improved. Furthermore, in the embodiment, the extension portion 124 is less likely to expand in a direction perpendicular to the X direction compared to when the folded shape of the extension portion 124 is fixed by a plurality of tapes spaced apart from each other along the X direction, and therefore, the insulation between the conductor such as the metal foil contained in the extension portion 124 and the conductor such as the sixth plate 360 ​​present around the extension portion 124 can be improved.

[0038] As shown in FIG. 4 , the exterior material 120 defines an opening 126 that at least partially exposes the adhesive 130 toward the −Y side from between the storage portion 122 and the inner extending portion 124b. In the example shown in FIG. 4 , the −Z side end of the opening 126 is defined by the −Y side surface of the portion of the storage portion 122 that is located on the −Y side with respect to the battery element 110. In the example shown in FIG. 4 , the +Z side end of the opening 126 is defined by the folded portion between the outer extending portion 124a and the inner extending portion 124b. As shown in FIG. 4 , the −Y side end surface of the adhesive 130 does not protrude toward the −Y side beyond the opening 126. In the example shown in FIG. 4 , the −Y side end surface of the adhesive 130 does not protrude toward the −Y side beyond a position that is approximately flush with the −Y side surface of the portion of the storage portion 122 that is located on the −Y side with respect to the battery element 110. Therefore, compared to when the -Y side end face of the adhesive 130 protrudes toward the -Y side beyond the opening 126, the Y-direction occupation area of ​​the stack of battery cells 100 can be reduced, and the Y-direction dimensional accuracy of the stack of battery cells 100 can be improved.

[0039] In one example, the adhesive 130 at least partially contains a photocurable adhesive. An example of a photocurable adhesive is an ultraviolet (UV) curable adhesive. When the adhesive 130 at least partially contains a photocurable adhesive, the adhesive 130 is cured by irradiating it with light such as UV while the uncured adhesive 130 is positioned between the -Y side portion of the accommodation portion 122 and the inner extending portion 124b. The shape and position of the uncured photocurable adhesive can be adjusted relatively easily. Therefore, when the adhesive 130 at least partially contains a photocurable adhesive, the shape and position of the adhesive 130 can be adjusted relatively easily.

[0040] In another example, the adhesive 130 at least partially contains a thermoplastic adhesive. An example of a thermoplastic adhesive is a hot melt adhesive. When the adhesive 130 at least partially contains a thermoplastic adhesive, the adhesive 130 is heated and softened and positioned between the -Y side portion of the accommodation portion 122 and the inner extending portion 124b, and then the adhesive 130 is cooled to harden the adhesive 130. Thermoplastic adhesives are relatively inexpensive. Therefore, when the adhesive 130 at least partially contains a thermoplastic adhesive, the adhesive 130 can be provided at a relatively low cost.

[0041] In the embodiment, as described with reference to Fig. 3 , the structural adhesive 362 is located between the +Z side extension portion 124 and the sixth plate 360. Therefore, at the +Z side end of the battery cell 100, vibrations applied to the battery module 10 can be mitigated by two layers of adhesive, the +Z side adhesive 130 and the structural adhesive 362. Furthermore, in the embodiment, as described with reference to Fig. 3 , the thermally conductive adhesive 352 is located between the -Z side extension portion 124 and the fifth plate 350. Therefore, at the -Z side end of the battery cell 100, vibrations applied to the battery module 10 can be mitigated by two layers of adhesive, the -Z side adhesive 130 and the thermally conductive adhesive 352.

[0042] 5 is a diagram illustrating an example of a manufacturing method for a battery cell 100 according to an embodiment. In FIG. 5, the Y direction is parallel to the vertical direction. The +Y side is the lower side in the vertical direction, and the −Y side is the upper side in the vertical direction.

[0043] In this example, the battery cell 100 according to the embodiment is manufactured as follows.

[0044] First, the battery element 110, the first exterior material portion 120a, and the second exterior material portion 120b are prepared. Next, the first exterior material portion 120a covers the +Y-side main surface of the battery element 110 and the +Y-side portion of the side surface around the battery element 110 in the Y direction, and the second exterior material portion 120b covers the -Y-side main surface of the battery element 110 and the -Y-side portion of the side surface around the battery element 110 in the Y direction. With the battery element 110 covered by the first exterior material portion 120a and the second exterior material portion 120b, the housing portion 122 houses the battery element 110, and the extension portion 124 is drawn out from the peripheral portion 123 of the housing portion 122. Next, the first exterior material portion 120a and the second exterior material portion 120b are joined to each other around the Y-direction of the battery element 110, including the extension portion 124, by a joining method such as heat fusion. By joining the first exterior material portion 120a and the second exterior material portion 120b, the exterior material 120, including the extension portion 124, is sealed around the battery element 110 in the Y direction.

[0045] 5, the outer extending portion 124a of the extending portion 124 is bent toward the storage portion 122, and the second exterior material portion 120b of the extending portion 124 is bent toward between the storage portion 122 and the outer extending portion 124a. By bending the extending portion 124, an opening 126 is defined between the storage portion 122 and the inner extending portion 124b. The opening 126 is open toward the -Y side.

[0046] Next, adhesive 130 containing a photocurable adhesive is prepared. Next, uncured adhesive 130 is introduced through opening 126 into the gap between the -Y side portion of housing portion 122 and inner extending portion 124b. Next, with uncured adhesive 130 compressed in the Z direction by the -Y side portion of housing portion 122 and inner extending portion 124b, UV or other light is irradiated onto adhesive 130 from the -Y side to cure adhesive 130. By curing adhesive 130 while compressed in the Z direction, adhesive 130 can be cured while peripheral portion 123 and the +Y side end of adhesive 130 are spaced apart from each other. The curing of adhesive 130 fixes the folded shape of exterior material 120.

[0047] The adhesive 130 may contain a thermoplastic adhesive instead of a photocurable adhesive. When the adhesive 130 contains a thermoplastic resin, the adhesive 130 in a softened state by heating is allowed to enter the gap between the -Y side portion of the storage portion 122 and the inward extending portion 124b through the opening 126. Next, the softened adhesive 130 is compressed in the Z direction by the -Y side portion of the storage portion 122 and the inward extending portion 124b, and the adhesive 130 is cooled to harden. By hardening the adhesive 130 while compressed in the Z direction, the adhesive 130 can be hardened while the peripheral portion 123 and the +Y side end of the adhesive 130 are spaced apart from each other.

[0048] The fixing of the bent shape of the extension portion 124 by hardening the adhesive 130 may be performed approximately simultaneously on the +Z side extension portion 124 and the −Z side extension portion 124, or may be performed at different times.

[0049] The battery cell 100 is manufactured by fixing the bent shape of the extension portion 124 on both the +Z side and the −Z side.

[0050] Fig. 6 is a diagram showing a first modification of Fig. 4. The first modification shown in Fig. 6 is similar to the embodiment shown in Fig. 4 except for the following points.

[0051] In the example shown in Fig. 6, the extension portion 124 does not have a portion corresponding to the inner extension portion 124b shown in Fig. 4 and is bent toward the housing portion 122. In the example shown in Fig. 6, an adhesive 130 is at least partially located between the housing portion 122 and the extension portion 124. The adhesive 130 bonds the housing portion 122 and the extension portion 124 to each other.

[0052] 6 , the peripheral portion 123 and the end of the adhesive 130 on the +Y side are spaced apart from each other. Therefore, in the same manner as in the embodiment, in Modification 1, it is possible to more easily prevent the folded shape of the extending portion 124 from returning to its original, unfolded shape, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other. Therefore, in Modification 1, it is possible to reduce the area occupied by the battery cell 100 in the direction perpendicular to the X direction and improve the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other.

[0053] As shown in FIG. 6 , the exterior material 120 defines an opening 126 that at least partially exposes the adhesive 130 toward the −Y side from between the storage portion 122 and the inner extending portion 124b. In the example shown in FIG. 6 , the −Z side end of the opening 126 is defined by the −Y side surface of the portion of the storage portion 122 that is located on the −Y side with respect to the battery element 110. In the example shown in FIG. 6 , the +Z side end of the opening 126 is defined by the tip portion of the extending portion 124. The −Y side end face of the adhesive 130 does not protrude beyond the opening 126 to the −Y side. In the example shown in FIG. 6 , the −Y side end face of the adhesive 130 does not protrude beyond a position that is approximately flush with the −Y side surface of the portion of the storage portion 122 that is located on the −Y side with respect to the battery element 110. Therefore, in variant example 1, as in the embodiment, the Y-direction occupation area of ​​the stack of battery cells 100 can be reduced and the Y-direction dimensional accuracy of the stack of battery cells 100 can be improved compared to when the -Y side end face of the adhesive 130 protrudes toward the -Y side beyond the opening 126.

[0054] 6, adhesive 130 bonds housing portion 122 and extension portion 124 to each other in a state in which extension portion 124 is at least partially bent non-perpendicularly with respect to the Z direction connecting battery element 110 and peripheral portion 123. In the example shown in Fig. 6, extension portion 124 is inclined obliquely toward the -Z side approaching housing portion 122 as it moves from peripheral portion 123 toward the -Y side tip of extension portion 124. Therefore, compared to a case in which extension portion 124 is bent perpendicular to the Z direction and arranged parallel to the Y direction, it is possible to prevent the -Y side tip of extension portion 124 from protruding to the -Y side from a position flush with the -Y side surface of housing portion 122.

[0055] Depending on the type of battery cell 100, the thickness of the battery element 110 in the Y direction may be relatively thin. Furthermore, from the perspective of sealing, the extension portion 124 may need to have a certain length. When the thickness of the battery element 110 in the Y direction is relatively thin and the extension portion 124 has a certain length, if the extension portion 124 is bent perpendicularly to the -Y side with respect to the Z direction, the -Y side tip of the extension portion 124 may protrude to the -Y side from a position flush with the -Y side surface of the housing portion 122. If the -Y side tip of the extension portion 124 protrudes to the -Y side from a position flush with the -Y side surface of the housing portion 122, it may be difficult to stack multiple battery cells 100 in the Y direction. However, in Modification 1, the extension portion 124 is bent at least partially non-perpendicularly to the Z direction. Therefore, even if the thickness of the battery element 110 in the Y direction is relatively thin and the extension portion 124 has a certain length, it is possible to prevent the tip of the extension portion 124 on the -Y side from protruding toward the -Y side from a position flush with the -Y side surface of the storage portion 122.

[0056] In Modification 1, the bent shape of the extension portion 124 is fixed by adhesive 130. Fixing the bent shape of the extension portion 124 with tape can be difficult because the shape of the extension portion 124 is unstable except when the extension portion 124 is bent perpendicular to the Z direction. However, by using adhesive 130, it is easier to fix the extension portion 124 in any bent shape than by using tape. Therefore, by using adhesive 130, not only can the extension portion 124 be easily bent perpendicular to the Z direction, but also the extension portion 124 can be easily bent non-perpendicularly to the Z direction.

[0057] The bending shape of the extension portion 124 is not limited to the example shown in Fig. 6. In one example, the extension portion 124 may be inclined obliquely toward the +Z side, away from the storage portion 122, as it moves from the peripheral portion 123 toward the tip of the extension portion 124 on the -Y side. In this example, the adhesive 130 also bonds the storage portion 122 and the extension portion 124 to each other in a state in which the extension portion 124 is at least partially bent non-perpendicularly with respect to the Z direction. Therefore, compared to when the extension portion 124 is bent perpendicular to the Z direction, it is possible to prevent the tip of the -Y side of the extension portion 124 from protruding toward the -Y side from a position flush with the -Y side surface of the storage portion 122.

[0058] Fig. 7 is a diagram showing a second modification of Fig. 4. The second modification shown in Fig. 7 is similar to the embodiment shown in Fig. 4 except for the following points.

[0059] Hereinafter, unless otherwise specified, the folded portion of the extending portion 124 refers to the folded portion of the -Y side portion of the outer extending portion 124a and the folded portion of the -Y side portion of the inner extending portion 124b in the extending portion 124.

[0060] 7, the extending portion 124 is inclined obliquely toward the +Z side away from the storage portion 122 as it moves from the peripheral portion 123 toward the folded-back portion of the extending portion 124. Therefore, also in the example shown in Fig. 7, the adhesive 130 bonds the storage portion 122 and the extending portion 124 to each other in a state in which the extending portion 124 is at least partially folded non-perpendicularly with respect to the Z direction. Therefore, compared to when the extending portion 124 is folded perpendicularly to the Z direction, it is possible to prevent the folded-back portion of the extending portion 124 from protruding toward the -Y side from a position flush with the -Y side surface of the storage portion 122.

[0061] In another example, the extending portion 124 may be inclined obliquely toward the −Z side approaching the storage portion 122 as it moves from the peripheral portion 123 toward the folded portion of the extending portion 124. In this other example as well, the adhesive 130 bonds the storage portion 122 and the extending portion 124 to each other in a state in which the extending portion 124 is at least partially folded non-perpendicularly with respect to the Z direction. Therefore, compared to when the extending portion 124 is folded perpendicularly to the Z direction, it is possible to prevent the folded portion of the extending portion 124 from protruding toward the −Y side from a position flush with the −Y side surface of the storage portion 122.

[0062] 7 , the peripheral portion 123 and the end of the adhesive 130 on the +Y side are spaced apart from each other. Therefore, in the second modification, as in the embodiment, it is possible to more easily prevent the folded shape of the extending portion 124 from returning to its original, unfolded shape, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other. Therefore, in the second modification, it is possible to reduce the area occupied by the battery cell 100 in the direction perpendicular to the X direction and improve the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other.

[0063] 7 , in Modification 2 as well, the -Y side end face of the adhesive 130 does not protrude toward the -Y side beyond the opening 126. Therefore, in Modification 2 as well, as in the embodiment, compared to when the -Y side end face of the adhesive 130 protrudes toward the -Y side beyond the opening 126, it is possible to reduce the Y-direction occupation area of ​​the stack of battery cells 100 and improve the Y-direction dimensional accuracy of the stack of battery cells 100.

[0064] Fig. 8 is a diagram showing a third modification of Fig. 4. The third modification shown in Fig. 8 is similar to the embodiment shown in Fig. 4 except for the following points.

[0065] 8, when viewed from the -X side, the extension portion 124 is curled clockwise from the peripheral portion 123 toward the tip of the extension portion 124. Therefore, in the example shown in Fig. 8, the adhesive 130 bonds the storage portion 122 and the extension portion 124 to each other while the extension portion 124 is at least partially curled. Therefore, compared to when the extension portion 124 is bent perpendicular to the Z direction, it is possible to prevent the extension portion 124 from protruding to the -Y side from a position flush with the -Y side surface of the storage portion 122.

[0066] 8 , the peripheral portion 123 and the end of the adhesive 130 on the +Y side are spaced apart from each other. Therefore, in the same manner as in the embodiment, in Modification 3, it is possible to more easily prevent the folded shape of the extending portion 124 from returning to its original, unfolded shape, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other. Therefore, in Modification 3, it is possible to reduce the area occupied by the battery cell 100 in the direction perpendicular to the X direction and improve the dimensional accuracy of the battery cell 100 in the direction perpendicular to the X direction, compared to when the peripheral portion 123 and the adhesive 130 are in contact with each other.

[0067] As shown in Fig. 8 , in Modification 3 as well, an opening 126 is defined between the storage portion 122 and the extension portion 124 due to the rounded shape of the extension portion 124. As shown in Fig. 8 , in Modification 3 as well, the -Y side end face of the adhesive 130 does not protrude beyond the opening 126 toward the -Y side. Therefore, in Modification 3 as well, as compared to when the -Y side end face of the adhesive 130 protrudes toward the -Y side beyond the opening 126, similar to the embodiment, it is possible to reduce the Y-direction occupation area of ​​the stack of battery cells 100 and improve the Y-direction dimensional accuracy of the stack of battery cells 100.

[0068] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0069] The present specification provides the following aspects. 1.1 A battery cell comprising: a battery element; an exterior material having a housing portion that houses the battery element and an extending portion drawn out from a peripheral portion of the housing portion that is at least partially located around the battery element; and an adhesive that bonds the housing portion and the extending portion to each other when the extending portion is at least partially folded toward the housing portion, wherein the adhesive and the peripheral portion are spaced apart. 1.2 The battery cell described in 1.1, wherein the extending portion includes a first portion folded toward the housing portion and a second portion folded toward between the housing portion and the first portion. 1.3 The battery cell described in 1.1 or 1.2, wherein the adhesive bonds the housing portion and the extending portion to each other when the extending portion is at least partially folded non-perpendicularly with respect to a direction connecting the battery element and the peripheral portion or when the extending portion is at least partially rolled up. 1.4. 1. A battery cell according to any one of 1.1 to 1.3, wherein the exterior material defines an opening that at least partially exposes the adhesive from between the housing portion and the extension portion, and the adhesive does not protrude beyond the opening. 1.5. A battery cell according to any one of 1.1 to 1.4, wherein the adhesive extends along the housing portion. 1.6. A battery cell according to any one of 1.1 to 1.5, wherein the adhesive at least partially contains a photocurable adhesive. 1.7. A battery cell according to any one of 1.1 to 1.5, wherein the adhesive at least partially contains a thermoplastic adhesive. 1.8. A battery module comprising the battery cell according to any one of 1.1 to 1.7, and a housing that houses the battery cell.1.9. A method for manufacturing a battery cell, comprising a step of bonding an accommodation portion of an exterior material that accommodates a battery element and an extension portion of the accommodation portion of the exterior material that is drawn out from a peripheral portion that is located at least partially around the battery element with an adhesive, with the extension portion being at least partially folded toward the accommodation portion, wherein the step of bonding the accommodation portion and the extension portion to each other includes a step of bonding the accommodation portion and the extension portion to each other with the adhesive while the adhesive and the peripheral portion are spaced apart from each other.

[0070] The present specification provides the following aspects. 2.1 A battery cell comprising: a battery element; an exterior material having a housing portion that houses the battery element and an extension portion drawn out from a peripheral portion of the housing portion that is at least partially located around the battery element; and an adhesive that bonds the housing portion and the extension portion to each other in at least one of a state in which the extension portion is at least partially folded non-perpendicularly with respect to a direction connecting the battery element and the peripheral portion or a state in which the extension portion is at least partially rolled. 2.2 The battery cell described in 2.1, wherein the extension portion includes a first portion folded toward the housing portion and a second portion folded toward between the housing portion and the first portion. 2.3 The battery cell described in 2.1 or 2.2, wherein the exterior material defines an opening that at least partially exposes the adhesive from between the housing portion and the extension portion, and the adhesive does not protrude beyond the opening. 2.4 The battery cell described in any one of 2.1 to 2.3, wherein the adhesive extends along the housing portion. 2.5 The battery cell according to any one of 2.1 to 2.4, wherein the adhesive at least partially contains a photocurable adhesive. 2.6 The battery cell according to any one of 2.1 to 2.4, wherein the adhesive at least partially contains a thermoplastic adhesive. 2.7 A battery module comprising: the battery cell according to any one of 2.1 to 2.6; and a housing that houses the battery cell. 2.8 A method for manufacturing a battery cell, comprising: bonding an accommodation portion of an exterior material that houses a battery element, and an extension portion of the exterior material that is drawn out from a peripheral edge portion of the accommodation portion that is located at least partially around the battery element, with an adhesive, in at least one of a state in which the extension portion is at least partially folded non-perpendicularly with respect to a direction connecting the battery element and the peripheral edge portion, or a state in which the extension portion is at least partially rolled.

[0071] This application claims priority based on Japanese Patent Application No. 2024-015461, filed February 5, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0072] 10 Battery module, 100 Battery cell, 110 Battery element, 120 Exterior material, 120a First exterior material portion, 120b Second exterior material portion, 122 Storage portion, 123 Peripheral portion, 124 Extension portion, 124a Outer extension portion, 124b Inner extension portion, 126 Opening, 130 Adhesive, 140 Terminal group, 142 Positive electrode terminal, 144 Negative electrode terminal, 200 Compression pad, 300 Module housing, 310 First plate, 320 Second plate, 330 Third plate, 340 Fourth plate, 350 Fifth plate, 352 Thermally conductive adhesive, 360 Sixth plate, 362 Structural adhesive

Claims

1. A battery cell comprising: a battery element; an exterior material having a housing portion that houses the battery element; and an extension portion that is drawn out from a peripheral portion of the housing portion that is at least partially located around the battery element; and an adhesive that bonds the housing portion and the extension portion to each other with the extension portion at least partially folded toward the housing portion, wherein the adhesive and the peripheral portion are spaced apart from each other.

2. The battery cell according to claim 1, wherein the extension portion includes a first portion bent toward the housing portion and a second portion bent toward between the housing portion and the first portion.

3. A battery cell as described in claim 1 or 2, wherein the adhesive bonds the housing portion and the extension portion to each other in at least one of a state in which the extension portion is at least partially folded non-perpendicularly to the direction connecting the battery element and the peripheral portion, and a state in which the extension portion is at least partially rolled up.

4. The battery cell according to claim 1 or 2, wherein the exterior material defines an opening that at least partially exposes the adhesive from between the housing portion and the extension portion, and the adhesive does not protrude beyond the opening.

5. The battery cell according to claim 1 or 2, wherein the adhesive extends along the housing portion.

6. The battery cell according to claim 1 or 2, wherein the adhesive at least partially contains a photocurable adhesive.

7. The battery cell according to claim 1 or 2, wherein the adhesive comprises at least a thermoplastic adhesive.

8. A battery module comprising: a battery cell according to claim 1 or 2; and a housing that houses the battery cell.

9. A method for manufacturing a battery cell, comprising a step of bonding together with an adhesive a storage portion of an exterior material that stores a battery element and an extension portion that is drawn out from a peripheral portion of the storage portion of the exterior material that is located at least partially around the battery element, with the extension portion being at least partially folded toward the storage portion, wherein the step of bonding together the storage portion and the extension portion includes a step of bonding the storage portion and the extension portion together with the adhesive with the adhesive and the peripheral portion spaced apart from each other.

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