Battery stack

Abstract

To facilitate bending a bundle including a plurality of current collector portions.SOLUTION: A plurality of first current collector portions 112a is pulled out from a laminated portion 100a. An exterior material 200 encases a battery element 100. A first tab 310 is connected to a plurality of first current collector portions 112a. The first current collector portion 112a between the laminated portion 100a and the first tab 310 has a first region RG1. In the first region RG1, the thickness of the bundle including the first current collector portion 112a in the third direction Z decreases from the laminated portion 100a to the first tab 310, and the rate of decrease in the thickness decreases from the laminated portion 100a to the first tab 310.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a battery and a method for manufacturing a battery. [Background technology]

[0002] In recent years, non-aqueous electrolyte secondary batteries, particularly lithium ion secondary batteries, have been developed. The lithium ion secondary battery includes a battery element having a positive electrode, a negative electrode, and a separator. The positive electrode, the negative electrode, and the separator form a laminated portion of the battery element. The lithium ion secondary battery further includes an exterior material that encases the battery element. A positive electrode current collector foil and a negative electrode current collector foil are drawn out from the positive electrode and the negative electrode of the laminated portion of the battery element, respectively. The positive electrode current collector foil and the negative electrode current collector foil are connected to a positive electrode tab and a negative electrode tab, respectively.

[0003] For example, a plurality of battery elements each wrapped in an exterior material may be stacked, as described in Patent Document 1. Patent Document 1 describes bundling a plurality of tabs by folding each tab (positive electrode tab or negative electrode tab) pulled out from the exterior material.

[0004] Patent Document 2 describes folding the exterior material together with the tab toward the battery element. Patent Document 2 describes that by folding the exterior material together with the tab, the length of the exterior material in the direction in which the tab is pulled out can be shortened compared to a case in which the exterior material is not folded, and that the volumetric energy density can be improved.

[0005] Patent Document 3 describes that by forming notches on both sides of the tab in the exterior material, the tab can be easily folded together with the exterior material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2016 / 020999 [Patent Document 2] Japanese Patent Application Publication No. 11-260327 [Patent Document 3] International Publication No. 2019 / 150904 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to shorten the length of the tab required for the tip of the tab to reach a specific position, the tab itself is not bent, but the portion of the exterior material between the laminate and the tab is bent to orient the tip of the tab in a specific direction. In this case, it is necessary to bend a bundle including multiple current collector parts (positive electrode current collector foils or negative electrode current collector foils) that are pulled out from the laminate and exist between the laminate and the tab. However, bending this bundle may cause the current collector parts (current collector foils) to break.

[0008] One object of the present invention is to make it easier to fold a bundle including a plurality of current collector parts. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0009] One aspect of the present invention is a battery element including a laminated portion including a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators, and a plurality of first current collector portions drawn out from the laminated portion; An exterior material that encases the battery element; a first tab connected to the plurality of first current collecting portions; Equipped with The battery has a first region in which the thickness of a bundle including the plurality of first current collector parts between the laminate and the first tab decreases from the laminate to the first tab, and the rate of decrease in thickness decreases from the laminate to the first tab.

[0010] Another aspect of the present invention is A method for manufacturing a battery includes a step of bundling a plurality of first current collector parts pulled out from a laminate including a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators toward a first tab, and joining the plurality of first current collector parts to the first tab while pressing at least a portion of the plurality of first current collector parts between the laminate and the first tab in the thickness direction of the bundle including the plurality of first current collector parts. Effect of the Invention

[0011] According to the above aspect of the present invention, it is possible to easily bend a bundle including a plurality of current collector portions. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a top view of the battery according to the embodiment. [Diagram 2] FIG. 2 is a right side view of the battery shown in FIG. [Diagram 3] FIG. 2 is a rear view of the battery shown in FIG. [Figure 4] FIG. 4 is an enlarged view of a region α shown in FIG. [Diagram 5] 2 is an enlarged view of a first tab and its periphery of the battery shown in FIG. 1. [Figure 6] 6 is a cross-sectional view taken along the line AA′ of FIG. 5. [Figure 7] 7A to 7C are diagrams for explaining an example of a method for manufacturing the battery shown in FIGS. 1 to 6. [Figure 8] 7A to 7C are diagrams for explaining an example of a method for manufacturing the battery shown in FIGS. 1 to 6. [Figure 9] FIG. 7 is a schematic diagram for explaining an example of application of the battery shown in FIGS. 1 to 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0014] In this specification, ordinal numbers such as "first," "second," "third," etc., unless otherwise specified, are used merely to distinguish between similarly named configurations and do not imply any particular characteristics (e.g., order or importance) of the configurations.

[0015] Fig. 1 is a top view of a battery 10 according to an embodiment. Fig. 2 is a right side view of the battery 10 shown in Fig. 1. Fig. 3 is a rear view of the battery 10 shown in Fig. 1. Fig. 4 is an enlarged view of an area α shown in Fig. 3. Fig. 5 is an enlarged view of a first tab 310 and its surroundings of the battery 10 shown in Fig. 1. Fig. 6 is an AA' cross-sectional view of Fig. 5.

[0016] The battery 10 includes a battery element 100, an exterior material 200, a first tab 310, and a second tab 320. The battery element 100 has a laminated portion 100a and a plurality of first current collector portions 112a. The laminated portion 100a includes a plurality of first electrodes 110, a plurality of second electrodes 120, and a plurality of separators 130.

[0017] 1 to 6, the first direction X is the length direction of the battery 10 (battery element 100). The positive direction of the first direction X (the direction indicated by the arrow indicating the first direction X) is the direction from the second tab 320 to the first tab 310, and is the front direction of the battery 10 (battery element 100). The negative direction of the first direction X (the direction opposite to the direction indicated by the arrow indicating the first direction X) is the direction from the first tab 310 to the second tab 320, and is the rear direction of the battery 10 (battery element 100). The second direction Y is a direction intersecting the first direction X, specifically, a direction perpendicular to the first direction X, and is the width direction of the battery 10 (battery element 100). The positive direction of the second direction Y (the direction indicated by the arrow indicating the second direction Y) is the right direction of the battery 10 when the battery 10 is viewed from the positive direction of the first direction X. The negative direction of the second direction Y (the opposite direction to the direction indicated by the arrow indicating the second direction Y) is the left direction of the battery 10 when the battery 10 is viewed from the positive direction of the first direction X. The third direction Z is a direction intersecting both the first direction X and the second direction Y, specifically, a direction perpendicular to both the first direction X and the second direction Y, and is the thickness (height) direction of the battery 10 (battery element 100). The positive direction of the third direction Z (the direction indicated by the arrow indicating the third direction Z) is the upward direction of the battery 10. The negative direction of the third direction Z (the opposite direction to the direction indicated by the arrow indicating the third direction Z) is the downward direction of the battery 10. The same applies to Figs. 7 to 9 described later.

[0018] In FIG. 5, a fold C indicated by a dashed line indicates the position of a fold that is formed when the exterior material 200 is folded between the laminated portion 100a and the first tab 310.

[0019] In this embodiment, the battery 10 is a lithium ion secondary battery. However, the battery 10 may be a battery other than a lithium ion secondary battery.

[0020] An overview of the battery 10 will be described with reference to FIG.

[0021] The first current collector parts 112a are each drawn out from the first electrodes 110 of the laminated part 100a toward the front of the laminated part 100a (positive direction of the first direction X). The exterior material 200 encases the battery element 100. The first tab 310 is connected to the first current collector parts 112a. The first current collector parts 112a between the laminated part 100a and the first tab 310 have a first region RG1 and a second region RG2. The first region RG1 is located closer to the first tab 310 than the laminated part 100a in the first direction X. The second region RG2 is located closer to the laminated part 100a than the first region RG1 in the first direction X. Also, the second region RG2 is located closer to the laminated part 100a than the first tab 310 in the first direction X.

[0022] In the first region RG1, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a (the distance in the third direction Z between two first current collector parts 112a located at both ends in the third direction Z among the plurality of first current collector parts 112a) decreases nonlinearly from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X). Specifically, in the first region RG1, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a decreases from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X), and the rate of decrease in the thickness decreases from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X). For example, in the first region RG1, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a can be matched to or approximated to a downwardly convex function with the position in the first direction X as a variable.

[0023] In the second region RG2, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a (the distance in the third direction Z between two first current collector parts 112a located at both ends in the third direction Z among the plurality of first current collector parts 112a) decreases nonlinearly from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X). Specifically, in the second region RG2, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a decreases from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X), and the rate of decrease in the thickness increases from the laminated part 100a to the first tab 310 (as it moves in the positive direction of the first direction X). For example, in the second region RG2, the thickness in the third direction Z of the bundle including the plurality of first current collector parts 112a can be matched to or approximated to an upwardly convex function with the position in the first direction X as a variable.

[0024] In this embodiment, the thickness (third direction Z) of the first region RG1 of the bundle of the first current collector parts 112a in the vicinity of the first tab 310 can be made thinner than the thickness (third direction Z) of the bundle of the first current collector parts 112a in the vicinity of the first tab 310 in a case where each first current collector part 112a extends straight from the laminated part 100a to the first tab 310. In this case, even if the multiple first current collector parts 112a are folded in the first region RG1 or in the vicinity of the first region RG1, the possibility of each first current collector part 112a being broken is reduced compared to a case where each first current collector part 112a extends straight from the laminated part 100a to the first tab 310. Therefore, the multiple first current collector parts 112a can be easily folded so that the tip of the first tab 310 (the end on the positive side of the first direction X) is directed in a specific direction. For example, the multiple first collector parts 112a and the exterior material 200 are folded so that the first region RG1 of the multiple first collector parts 112a, or the region of the first collector parts 112a between the laminated part 100a and the first tab 310 on the first tab 310 side relative to the first region RG1, forms crease C (Figure 5).

[0025] The multiple first current collector parts 112a between the laminate part 100a and the first tab 310 may further have a region located on the first tab 310 side with respect to the first region RG1. In this region, the minimum value of the thickness in the third direction Z of the bundle including the multiple first current collector parts 112a (the distance in the third direction Z between two first current collector parts 112a located at both ends in the third direction Z among the multiple first current collector parts 112a) is, for example, 50% or more, 65% or more, 80% or more, or 95% or more of the maximum value of the thickness in the third direction Z of the bundle including the multiple first current collector parts 112a.

[0026] The second current collector parts (not shown) drawn from the second electrodes 120 toward the rear of the laminated unit 100a (negative direction of the first direction X) and the second tab 320 may have a relationship similar to that shown in FIG. 6. That is, the second current collector parts (not shown) may have regions corresponding to the first region RG1 and the second region RG2, similar to the first current collector parts 112a. Alternatively, the second current collector parts (not shown) drawn from the second electrode 120 and the second tab 320 may have a relationship different from that shown in FIG. 6. For example, the second current collector parts (not shown) may not have regions corresponding to the first region RG1 and the second region RG2.

[0027] The battery 10 will be described in detail with reference to FIGS.

[0028] The first tab 310 is located at the front of the battery 10 (positive direction in the first direction X), and the second tab 320 is located at the rear of the battery 10 (negative direction in the first direction X). However, the first tab 310 and the second tab 320 may be located on a common side of the battery 10, for example, at the front (positive direction in the first direction X) or rear (negative direction in the first direction X) of the battery 10. In this case, the first tab 310 and the second tab 320 are, for example, aligned in the second direction Y.

[0029] The exterior material 200 encases the battery element 100 together with an electrolyte (not shown). The exterior material 200 has a first exterior material sheet 210 and a second exterior material sheet 220. The first exterior material sheet 210 covers the upper surface (the surface on the positive side of the third direction Z) of the laminated portion 100a, and the second exterior material sheet 220 covers the lower surface (the surface on the negative side of the third direction Z) of the laminated portion 100a. The first exterior material sheet 210 and the second exterior material sheet 220 are bonded to each other in a region surrounding the laminated portion 100a when viewed from the third direction Z. In addition, both sides of the laminated portion 100a of the exterior material 200 in the second direction Y are folded back toward the laminated portion 100a. In detail, as shown in FIG. 4, the portion of the exterior packaging material 200 on the negative side in the second direction Y has a portion folded from the negative direction of the second direction Y toward the positive direction of the third direction Z, and a portion folded back from the folded portion and located on the positive side of the second direction Y with respect to the folded portion. However, the folded shape of the exterior packaging material 200 is not limited to the example shown in FIG. 4. In addition, the portion of the exterior packaging material 200 on the positive side in the second direction Y may have a shape similar to the shape shown in FIG. 4, or may have a shape different from the shape shown in FIG. 4. According to this embodiment, the volume of the battery 10 can be reduced and the volumetric energy density of the battery 10 can be improved, compared to a case in which the exterior packaging material 200 is not folded back.

[0030] In this embodiment, both of the two sides of the laminated portion 100a of the exterior packaging material 200 in the second direction Y are folded back toward the laminated portion 100a. However, only one of the two sides of the laminated portion 100a of the exterior packaging material 200 in the second direction Y may be folded back toward the laminated portion 100a. In other words, at least one of the two sides of the laminated portion 100a of the exterior packaging material 200 in the second direction Y may be folded back toward the laminated portion 100a.

[0031] In this embodiment, the exterior material 200 has two exterior material sheets (a first exterior material sheet 210 and a second exterior material sheet 220). However, the exterior material 200 may have only one exterior material sheet. In this case, the exterior material sheet may be folded back on one of both sides in the second direction Y of the battery element 100 (the laminated portion 100a) so that a part of the exterior material sheet covers the upper surface (the surface on the positive side of the third direction Z) of the laminated portion 100a and another part of the exterior material sheet covers the lower surface (the surface on the negative side of the third direction Z) of the laminated portion 100a, and the part of the exterior material sheet and the other part of the exterior material sheet are bonded together.

[0032] A notch 202 is provided on each of both sides of the first tab 310 in the second direction Y of the exterior material 200. The notch 202 is open in a direction from the laminated portion 100a side toward the first tab 310 side (positive direction of the first direction X) and in a direction from the first tab 310 toward both sides of the first tab 310 in the second direction Y (negative direction of the second direction Y for the notch 202 on the left side (negative side of the second direction Y) and positive direction of the second direction Y for the notch 202 on the right side (positive side of the second direction Y)). In this case, when the exterior material 200 is folded along the crease C between the laminated portion 100a and the first tab 310, the notch 202 can be used as the starting point of the crease C of the exterior material 200. Therefore, in this embodiment, it is easier to fold the exterior material 200 between the laminated portion 100a and the first tab 310 compared to a case in which the notch 202 is not provided. Furthermore, when the notch 202 is provided, it is not necessary to fold the folded-back portions on both sides of the exterior material 200 in the second direction Y from the positive direction of the first direction X toward the positive or negative direction of the third direction Z. The folded-back portions on both sides of the exterior material 200 in the second direction Y are difficult to fold from the positive direction of the first direction X toward the positive or negative direction of the third direction Z. However, in this embodiment, as described above, it is not necessary to fold the folded-back portions on both sides of the exterior material 200 in the second direction Y. Therefore, in this embodiment, it is easier to fold the exterior material 200 between the laminated portion 100a and the first tab 310 compared to when the notch 202 is not provided.

[0033] In the direction from the first tab 310 side toward the laminated unit 100a side (negative direction of the first direction X), the edge of the notch 202 on the laminated unit 100a side is located on the first tab 310 side with respect to the first region RG1 of the multiple first current collector parts 112a. In this case, the distance between the edge of the notch 202 on the laminated unit 100a side and the front surface of the laminated unit 100a (the surface on the positive side of the first direction X) can be made larger than when the edge of the notch 202 on the laminated unit 100a side is aligned with the first region RG1 of the multiple first current collector parts 112a in the direction from the first tab 310 side toward the laminated unit 100a side (negative direction of the first direction X). Therefore, the deterioration of the sealing performance of the exterior material 200 caused by providing the notch 202 can be reduced. However, in the direction from the first tab 310 side toward the laminate 100a side (the negative direction of the first direction X), the edge of the notch 202 on the laminate 100a side may be aligned with the first region RG1 of the multiple first collector portions 112a, or may be located on the laminate 100a side relative to the first region RG1.

[0034] The end of the left notch 202 (negative side in the second direction Y) on the first tab 310 side is located closer to the left end (negative side in the second direction Y) of the first tab 310 than the left end (left side surface) of the laminated unit 100a (negative side in the second direction Y) in the second direction Y. In this case, the length of the fold C can be made shorter than when the end of the left notch 202 (negative side in the second direction Y) on the first tab 310 side is located closer to the left end (left side surface) of the laminated unit 100a (negative side in the second direction Y) than the left end (negative side in the second direction Y) of the first tab 310 in the second direction Y. However, the end of the left notch 202 (negative side in the second direction Y) on the first tab 310 side may be located closer to the left end (negative side in the second direction Y) of the laminated unit 100a in the second direction Y than the left end (negative side in the second direction Y) of the first tab 310. Alternatively, the end of the left notch 202 (negative side in the second direction Y) on the first tab 310 side may be located equidistant from the left end (negative side in the second direction Y) of the first tab 310 and the left end (negative side in the second direction Y) of the laminated unit 100a in the second direction Y. The above-mentioned matters also apply to the end of the right notch 202 (positive side in the second direction Y) on the first tab 310 side.

[0035] The region in which the notch 202 is provided is not limited to this embodiment. For example, the notch 202 may be provided on only one of both sides of the first tab 310 in the second direction Y of the exterior material 200. That is, the notch 202 may be provided on at least one of both sides of the first tab 310 in the second direction Y of the exterior material 200. Even when the notch 202 is provided on only one of both sides of the first tab 310 in the second direction Y of the exterior material 200, the exterior material 200 can be easily folded compared to a case in which the notch 202 is not provided.

[0036] The direction in which the notch 202 is open is not limited to the present embodiment. For example, the notch 202 may not be open in the direction from the first tab 310 to both sides of the first tab 310 in the second direction Y (the negative direction of the second direction Y for the notch 202 on the left side (negative side of the second direction Y) and the positive direction of the second direction Y for the notch 202 on the right side (positive side of the second direction Y)), but may be open only in the direction from the laminated portion 100a side to the first tab 310 side (positive direction of the first direction X). Even in this case, it is possible to make it easier to fold the exterior material 200 between the laminated portion 100a and the first tab 310, compared to a case in which the notch 202 is not provided.

[0037] In addition, the notches 202 on both sides of the second tab 320 of the exterior material 200 in the second direction Y may be the same as the notch 202 on the first tab 310 side, or may be different from the notch 202 on the first tab 310 side. Alternatively, the notch 202 may not be provided on at least one of the first tab 310 side and the second tab 320 side.

[0038] The battery element 100 will be described in detail with reference to FIG.

[0039] The first electrode 110 and the second electrode 120 have different polarities. The first electrode 110, the first current collector 112, the first active material layer 114, the second electrode 120, the second current collector 122, and the second active material layer 124 are a positive electrode, a positive electrode current collector, and a positive electrode active material layer, a negative electrode, a negative electrode current collector, and a negative electrode active material layer, respectively. However, the first electrode 110, the first current collector 112, the first active material layer 114, the second electrode 120, the second current collector 122, and the second active material layer 124 may be a negative electrode, a negative electrode current collector, and a negative electrode active material layer, a positive electrode, a positive electrode current collector, and a positive electrode active material layer, respectively.

[0040] The first electrode 110 has a first current collector 112 and a first active material layer 114. In this embodiment, the first active material layer 114 is located on both the upper surface (the surface on the positive side in the third direction Z) and the lower surface (the surface on the negative side in the third direction Z) of the first current collector 112. However, the first active material layer 114 may be located on only one of the upper surface and the lower surface of the first current collector 112.

[0041] The second electrode 120 has a second current collector 122 and a second active material layer 124. In this embodiment, the second active material layer 124 is located on both the upper surface (the surface on the positive side in the third direction Z) and the lower surface (the surface on the negative side in the third direction Z) of the second current collector 122. However, the second active material layer 124 may be located on only one of the upper surface and the lower surface of the second current collector 122.

[0042] The separator 130 is located between the first electrode 110 and the second electrode 120 that are adjacent to each other in the third direction Z. The separator 130 is provided to prevent contact (i.e., short circuit) between the first electrode 110 and the second electrode 120 that are adjacent to each other in the third direction Z.

[0043] The laminated portion 100a has a plurality of first electrodes 110, second electrodes 120, and separators 130 laminated in the third direction Z. The plurality of first electrodes 110 and the plurality of second electrodes 120 are alternately stacked along the third direction Z such that the separators 130 are located between adjacent first electrodes 110 and second electrodes 120.

[0044] The first current collector portion 112a is connected to the first current collector 112 of the battery element 100. Specifically, the first current collector 112 and the first current collector portion 112a are an integrated conductive portion (conductive foil). In other words, this conductive portion (conductive foil) is the first current collector 112 of the first electrode 110 in a region overlapping with the second electrode 120 and the separator 130 in the third direction Z, and is the first current collector portion 112a on the outside of the laminated portion 100a (the positive side of the laminated portion 100a in the first direction X). The same is true for a second current collector portion (not shown) drawn from the second electrode 120 toward the rear of the laminated portion 100a (the negative direction of the first direction X).

[0045] Figures 7 and 8 are diagrams for explaining an example of a method for manufacturing the battery 10 shown in Figures 1 to 6. Figure 7 corresponds to Figure 6. Figure 8 corresponds to Figure 1.

[0046] First, the battery element 100 is formed. The battery element 100 is formed by alternately stacking a plurality of first electrodes 110 and a plurality of second electrodes 120 such that a separator 130 is disposed between adjacent first electrodes 110 and second electrodes 120.

[0047] Next, as shown in FIG. 7, the multiple first current collector portions 112a are bundled together around a first tab 310, and the multiple first current collector portions 112a are joined to the first tab 310 while at least a portion of the multiple first current collector portions 112a is pressed in the thickness direction (third direction Z) of the bundle including the multiple first current collector portions 112a by a first jig J1 and a second jig J2 between the laminated portion 100a and the first tab 310.

[0048] At least a portion of the first current collector parts 112a is pressed in the thickness direction (third direction Z) of the bundle including the first current collector parts 112a by placing the first current collector parts 112a on the second jig J2 and pressing the first jig J1 from above (positive direction of the third direction Z) to below (negative direction of the third direction Z) the first current collector parts 112a. In this case, it is not necessary to perform a joining process such as welding on the parts of the first current collector parts 112a pressed in the thickness direction (third direction Z) so that distortion, which will be described later, remains. However, the method of pressing the first current collector parts 112a is not limited to the method according to this embodiment.

[0049] The first current collector portions 112a are joined to the first tab 310 by welding, such as heat welding or ultrasonic welding.

[0050] In this embodiment, each of the first current collector portions 112a is joined to the first tab 310 in a state in which it is distorted (i.e., a force that distorts it) into a shape that extends straight from the laminate portion 100a toward the first tab 310. Even after this force is released (e.g., after the first jig J1 and the second jig J2 are separated from the multiple first current collector portions 112a), the distortion imparted to each of the first current collector portions 112a remains. As a result, a first region RG1 and a second region RG2 (FIG. 6) are formed.

[0051] A plurality of second collector portions (not shown) each extending from a plurality of second electrodes 120 toward the rear of the laminate 100a (the negative direction of the first direction X) can also be joined to the second tab 320 in a manner similar to that described using FIG. 7.

[0052] Next, as shown in FIG. 8, the upper surface (the surface on the positive side of the third direction Z) of the laminated portion 100a is covered with the first exterior material sheet 210, and the lower surface (the surface on the negative side of the third direction Z) of the laminated portion 100a is covered with the second exterior material sheet 220. Next, in the region surrounding the laminated portion 100a as viewed from the third direction Z, the first exterior material sheet 210 and the second exterior material sheet 220 are joined to each other, for example, by welding. Next, notches 202 (for example, FIG. 1) are formed at the four corners of the exterior material 200. Next, as shown in FIG. 4, both sides of the laminated portion 100a of the exterior material 200 in the second direction Y are folded back toward the laminated portion 100a.

[0053] In this manner, the battery 10 is manufactured.

[0054] Fig. 9 is a schematic diagram for explaining an example of an application of the battery 10 shown in Fig. 1 to Fig. 6. An example of an application of the battery 10 will be explained using Fig. 9 with reference to Figs.

[0055] In this example, a plurality of batteries 10 (battery elements 100) are stacked along the thickness direction of each battery 10 (third direction Z). The plurality of first current collector portions 112a and the exterior material 200 of each battery 10 (battery element 100) are folded along crease C. The first tabs 310 of each battery 10 (battery element 100) are located in front of each battery element 100 (positive side in the first direction X) and are bundled at a location located at the center of the plurality of batteries 10 (plurality of battery elements 100) in the third direction Z.

[0056] The multiple first current collector portions 112a and the exterior material 200 of each battery 10 (battery element 100) are bent so that the tips (ends on the positive side of the first direction X) of the first tabs 310 are oriented in different directions relative to the direction from the laminated portion 100a toward the first tabs 310 (the positive direction of the first direction X). In the example shown in Fig. 9, the tips (ends on the positive side of the first direction X) of the first tabs 310 of the first-stage battery 10 (battery element 100) are oriented in a direction tilted by a predetermined angle from the positive direction of the first direction X toward the positive direction of the third direction Z from the negative direction of the third direction Z. The tip (end on the positive side of the first direction X) of the first tab 310 of the second stage battery 10 (battery element 100) facing from the negative direction to the positive direction of the third direction Z is tilted at an angle from the positive direction of the first direction X to the positive direction of the third direction Z by an angle smaller than the predetermined angle of the first tab 310 of the first stage battery 10 (battery element 100). The tip (end on the positive side of the first direction X) of the first tab 310 of the third stage battery 10 (battery element 100) facing from the negative direction to the positive direction of the third direction Z is tilted at a predetermined angle from the positive direction of the first direction X to the negative direction of the third direction Z. The tip (the end on the positive side of the first direction X) of the first tab 310 of the fourth row battery 10 (battery element 100) is tilted from the positive direction of the first direction X to the negative direction of the third direction Z by an angle greater than the above-mentioned specified angle of the first tab 310 of the third row battery 10 (battery element 100) with respect to the positive direction of the first direction X.

[0057] Although the embodiments 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. Below, examples of reference forms are given. 1. A battery element having a laminated portion including a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators, and a plurality of first current collector portions drawn out from the laminated portion; An exterior material that encases the battery element; a first tab connected to the plurality of first current collecting portions; Equipped with the plurality of first current collector parts between the laminate and the first tab have a first region in which a thickness of a bundle including the plurality of first current collector parts decreases from the laminate to the first tab, and a rate of decrease in the thickness decreases from the laminate to the first tab. 2. The battery according to 1., the plurality of first current collector parts between the laminate and the first tab are located on the laminate side relative to the first region, and the bundle including the plurality of first current collector parts has a second region in which the thickness of the bundle decreases from the laminate to the first tab, and the rate of decrease in the thickness increases from the laminate to the first tab. 3. The battery according to 1. or 2., The battery, wherein the exterior material has a notch on at least one of both sides of the first tab, the notch opening in a direction from the laminated portion side toward the first tab side. 4. The battery according to 3., a battery, in a direction from the first tab side toward the stacked portion side, the edge of the notch on the stacked portion side is located on the first tab side relative to the first regions of the multiple first collector portions. 5. The battery according to 3. or 4., The battery, wherein the notches open in a direction from the first tab toward both sides of the first tab. 6. The battery according to any one of 3. to 5., A battery, wherein at least one of both sides of the laminated portion of the exterior material is folded back toward the laminated portion. 7. The battery according to any one of 1. to 6., the plurality of first current collector parts and the exterior material are folded so that the first regions of the plurality of first current collector parts, or a region of the plurality of first current collector parts between the laminated portion and the first tab that is on the first tab side relative to the first regions, forms a crease. 8. The battery according to 7., A plurality of the battery elements stacked on top of each other; a battery in which the multiple first collector portions and the exterior material of each battery element are folded so that the tips of the first tabs of each battery element are oriented in different directions relative to the direction from the laminated portion toward the first tabs. 9. A method for manufacturing a battery, comprising the steps of bundling a plurality of first current collector parts pulled out from a laminate including a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators toward a first tab, and joining the plurality of first current collector parts to the first tab while pressing at least a portion of the plurality of first current collector parts between the laminate and the first tab in the thickness direction of the bundle including the plurality of first current collector parts. [Explanation of symbols]

[0058] 10 batteries 100 Battery elements 100a Laminated section 110 1st electrode 112 First current collector 112a First current collector part 114 First active material layer 120 2nd electrode 122 Second current collector 124 Second active material layer 130 Separator 200 Exterior materials 202 Notch 210 First exterior material sheet 220 Second exterior material sheet 310 First Tab 320 Second Tab C Fold J1 First jig J2 Second jig RG1 1st area RG2 2nd area X 1st direction Y Second direction Z 3rd direction

Claims

1. A plurality of batteries stacked on top of each other; Each of the plurality of batteries comprises: a battery element including a laminated portion including a plurality of first electrodes, a plurality of second electrodes, and a separator located between the plurality of first electrodes and the plurality of second electrodes, and a plurality of first current collector portions drawn out from the laminated portion; An exterior material that encases the battery element; a first tab having a base end located on a side where the battery element is located and connected to the first current collector portions; having in each of the plurality of batteries, the plurality of first current collector portions and the exterior material have a folding portion that is folded along a crease formed in a portion of the plurality of first current collector portions and the exterior material that is located between the laminate portion and the base end of the first tab, In each of the plurality of batteries, the base end of the first tab and a tip end of the exterior material bent at the bend portion are oriented in opposite directions in the same direction, the first tabs of the batteries are bundled together; in each of the plurality of batteries, the plurality of first current collector parts between the stacked portion and the first tab have a first region in which a thickness of a bundle including the plurality of first current collector parts decreases from the stacked portion to the first tab, and a rate of decrease in the thickness decreases from the stacked portion to the first tab; a battery stack, in which, in each of the plurality of batteries, the folds of the plurality of first current collector parts are located in one of the first regions of the plurality of first current collector parts and a region of the plurality of first current collector parts on the first tab side relative to the first region.

2. The battery stack according to claim 1 , a battery stack, in which, in each of the plurality of batteries, the plurality of first current collector parts between the stack portion and the first tab are located on the stack portion side with respect to the first region, and the stack has a second region in which the thickness of the bundle including the plurality of first current collector parts decreases from the stack portion to the first tab, and a rate of decrease in the thickness increases from the stack portion to the first tab.

3. The battery stack according to claim 1 or 2, A battery stack, wherein in each of the plurality of batteries, a notch is provided in the exterior material on at least one of both sides of the first tab, the notch opening in a direction from the stacked portion side toward the first tab side.

4. The battery stack according to claim 3 , a battery stack, in which, in each of the plurality of batteries, in a direction from the first tab side toward the stack side, the edge of the notch on the stack side is located on the first tab side relative to the first regions of the plurality of first current collector portions.

5. The battery stack according to claim 3 or 4, a battery stack, wherein in each of the plurality of batteries, the notch is open in a direction from the first tab toward both sides of the first tab.

6. The battery stack according to any one of claims 3 to 5, a battery stack, in which in each of the plurality of batteries, at least one of both sides of the stacked portion of the exterior material is folded back toward the stacked portion.

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