Battery and battery manufacturing method

Abstract

This battery, according to an embodiment of the present invention, comprises: an exterior member; an electrode terminal; an electrode group; a conductive member; and a joining part. The electrode terminal is installed on the exterior member. The electrode group is stored within an interior cavity of the exterior member, and is provided with a protruding current collector tab. The conductive member electrically connects the electrode terminal and the current collector tab. The joining part connects the current collector tab and the conductive member. The joining part includes a recessed portion and an edge portion. The recessed portion is recessed toward the side, of the current collector tab, where the conductive member is positioned. With respect to the recessed portion, a second dimension between both ends in a second direction that crosses a first direction is smaller than a first dimension between both ends in the first direction. The edge portion surrounds the recessed portion, and a remaining amount of burrs is greater at a location adjacent to the recessed portion from the first direction than at a location adjacent to the recessed portion from the second direction.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to batteries and methods for manufacturing batteries. [Background technology]

[0002] Some batteries, such as lithium-ion secondary batteries, have an electrode group including a positive electrode and a negative electrode housed in the internal cavity of a housing member. In this battery, electrode terminals are attached to the housing member. The electrode group includes a current collector and an active material-containing layer supported on the current collector. The current collector includes a current collecting tab as a portion not supported by the active material-containing layer. The current collecting tab is electrically connected to the electrode terminal via a conductive material such as a lead. The current collecting tab includes multiple strip-shaped portions stacked on top of each other.

[0003] During the manufacturing of the above-described battery, the stacked strip portions of the current collecting tab are joined to a conductive member, for example, by ultrasonic bonding. That is, the stacked strip portions of the current collecting tab and the conductive member are joined by mutual deformation. When the strip portions and the conductive member are joined in this manner, a recess is formed at the connection portion, and burrs may be formed around the periphery of the recess. Burrs are protrusions that occur on the periphery during the process of forming the recess, or residual portions of the strip portions. In such joining, it is desirable to reduce the formation of burrs around the periphery of the recess where the strip portions and the conductive member are joined. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-074611 [Patent Document 2] Japanese Patent Application Publication No. 2018-094559 [Patent Document 3] Japanese Patent Application Publication No. 2007-330851 [Patent Document 4] Japanese Patent Application Publication No. 2017-054704 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a battery and a method for manufacturing the battery that can reduce the formation of burrs around the periphery of the recess where the strip portion and the conductive member are joined. [Means for solving the problem]

[0006] The battery of the embodiment includes a housing member, an electrode terminal, an electrode group, a conductive member, and a joint. The electrode terminal is attached to the housing member. The electrode group is housed in an internal cavity of the housing member and includes a protruding current collecting tab. The conductive member electrically connects the electrode terminal and the current collecting tab. The joint connects the current collecting tab and the conductive member. The joint includes a recess and a peripheral portion. The recess is recessed toward the side of the current collecting tab where the conductive member is located, and a first dimension between both ends in the first direction is smaller than a second dimension between both ends in a second direction intersecting the first direction. The peripheral portion surrounds the recess, and a portion adjacent to the recess from the first direction has a larger amount of remaining burrs than a portion adjacent to the recess from the second direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically illustrating an example of a battery according to an embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing the configuration of the electrode group of FIG. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the current collecting tab of the electrode group of FIG. [Figure 4] FIG. 4 is a schematic view showing an example of a recess in a current collecting tab formed in the electrode group of FIG. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a cross section taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a cross section taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a diagram showing the bonding strength when a recessed portion according to the embodiment is formed. [Figure 8] FIG. 8 is a diagram showing the bonding time when a recessed portion according to the embodiment is formed. [Figure 9] FIG. 9 is a diagram showing bonding energy when a recessed portion according to the embodiment is formed. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a battery according to a modified example of the embodiment, taken along a cross section perpendicular to the depth direction of the battery. [Figure 11] FIG. 11 is a perspective view schematically showing an example of a battery according to another modified example of the embodiment. [Figure 12] FIG. 12 is a cross-sectional view schematically showing a joint portion of a battery according to another modified example shown in FIG. 11, taken along a cross section perpendicular to the first direction. [Figure 13] FIG. 13 is a cross-sectional view schematically showing a joint portion of a battery according to another modified example shown in FIG. 11, taken along a cross section perpendicular to the second direction. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] (Embodiment) FIG. 1 shows a battery 1 according to an embodiment. As shown in FIG. 1, the battery 1 includes an electrode group 2 and an exterior member 3. The exterior member 3 includes an exterior container 5 and a lid member 6. The exterior container 5 and the lid member 6 are each formed of a metal such as aluminum, an aluminum alloy, iron, copper, or stainless steel. The battery 1 (exterior container 5) has a depth direction (the direction indicated by arrows X1 and X2), a lateral direction (the direction indicated by arrows Y1 and Y2) that intersects (is perpendicular or substantially perpendicular to) the depth direction, and a height direction (the direction indicated by arrows Z1 and Z2) that intersects (is perpendicular or substantially perpendicular to) both the depth and lateral directions. The depth dimension of the battery 1 and the exterior container 5 is smaller than the lateral dimension and the height dimension. FIG. 1 is a perspective view showing the battery 1 and the exterior container 5 disassembled into individual components.

[0010] The outer container 5 has a bottom wall 7 and a peripheral wall 8. An internal cavity 10 in which the electrode group 2 is housed is defined by the bottom wall 7 and the peripheral wall 8. In the outer container 5, the internal cavity 10 opens toward the side opposite the bottom wall 7 in the height direction. The lid member 6 is attached to the peripheral wall 8 at an end opposite the bottom wall 7. Therefore, the lid member 6 closes the opening of the internal cavity 10 of the outer container 5. The lid member 6 and the bottom wall 7 face each other in the height direction, sandwiching the internal cavity 10 therebetween.

[0011] The electrode group 2 includes a pair of electrodes 13, a pair of current collectors 14, and a pair of current collecting tabs 15. One of the pair of electrodes 13 is a positive electrode 13A, and the other of the pair of electrodes 13 other than the positive electrode 13A is a negative electrode 13B. One of the pair of current collectors 14 is a positive electrode current collector 14A, and the other of the pair of current collectors 14 other than the positive electrode current collector 14A is a negative electrode current collector 14B. One of the pair of current collecting tabs 15 is a positive electrode current collecting tab 15A, and the other of the pair of current collecting tabs 15 other than the positive electrode current collecting tab 15A is a negative electrode current collecting tab 15B. Each of the pair of current collecting tabs 15 has multiple strip-shaped portions bundled together. In the electrode group 2, a separator (not shown) is interposed between the positive electrode 13A and the negative electrode 13B. The separator is made of an electrically insulating material and electrically insulates the positive electrode 13A from the negative electrode 13B.

[0012] The positive electrode current collector 14A is formed from a positive electrode current collector foil or the like. A positive electrode active material-containing layer (not shown) is formed on the surface of the positive electrode current collector 14A. The positive electrode current collector 14A is, for example, an aluminum foil or an aluminum alloy foil. The thickness of the positive electrode current collector 14A is approximately 10 μm to 20 μm. The positive electrode active material-containing layer includes a positive electrode active material. The positive electrode active material-containing layer may optionally contain a binder and a conductive agent. The positive electrode active material is, for example, an oxide, sulfide, or polymer capable of absorbing and releasing lithium ions. The positive electrode current collector tab 15A is a portion of the positive electrode current collector 14A on which the positive electrode active material-containing layer is not supported (unsupported). The positive electrode current collector tab 15A protrudes from the negative electrode 13B and the separator.

[0013] The negative electrode current collector 14B is formed from a negative electrode current collector foil or the like. A negative electrode active material-containing layer (not shown) is formed on the surface of the negative electrode current collector 14B. The negative electrode current collector 14B is, for example, an aluminum foil, an aluminum alloy foil, or a copper foil. The thickness of the negative electrode current collector 14B is approximately 10 μm to 20 μm. The negative electrode active material-containing layer includes a negative electrode active material. The negative electrode active material-containing layer may optionally contain a binder and a conductive agent. The negative electrode active material is, for example, a metal oxide, a metal sulfide, a metal nitride, or a carbon material capable of absorbing and releasing lithium ions. The negative electrode current collector tab 15B is a portion of the negative electrode current collector 14B on which the negative electrode active material-containing layer is not supported (unsupported). The negative electrode current collector tab 15B protrudes from the positive electrode 13A and the separator on the side opposite to the side from which the positive electrode current collector tab 15A protrudes.

[0014] In one example of an electrode group 2, a positive electrode 13A, a negative electrode 13B, and a separator are wound around a winding axis W. The positive electrode 13A is provided offset to one side of the separator in the axial direction along the winding axis W. The negative electrode 13B is provided offset to the opposite side of the separator in the axial direction from the positive electrode 13A. Therefore, a pair of current collector tabs 15 (positive electrode current collector tab 15A and negative electrode current collector tab 15B) protrude outward in the axial direction from the separator. In this case, the positive electrode current collector tab 15A protrudes to one side of the separator in the axial direction. The negative electrode current collector tab 15B protrudes in the opposite direction from the separator to the direction in which the positive electrode current collector tab 15A protrudes.

[0015] In another example of an electrode group 2, multiple positive electrodes 13A and multiple negative electrodes 13B are alternately stacked. That is, the electrode group 2 has a stack structure. The multiple positive electrodes 13A are offset to one side relative to the separator. The multiple negative electrodes 13B are offset to the opposite side of the separator from the positive electrodes 13A. Therefore, a pair of current collecting tabs 15 protrude outward from the separator. Specifically, the positive electrode current collecting tab 15A protrudes from the separator in the lateral direction of the battery 1, and the negative electrode current collecting tab 15B protrudes from the separator on the opposite side of the positive electrode current collecting tab 15A in the lateral direction of the battery 1.

[0016] In the following description, the electrode group 2 is described as being the wound-type electrode group described above, but the electrode group 2 is not limited to this. As shown in Fig. 1 , one of the pair of current collecting tabs 15 protrudes to one side in the lateral direction of the battery 1 (the axial direction along the winding axis W). The other of the pair of current collecting tabs 15 protrudes in the lateral direction of the battery 1 opposite to the direction in which one of the pair of current collecting tabs 15 protrudes. In other words, the positive electrode current collecting tab 15A protrudes to one side in the lateral direction of the battery 1, and the negative electrode current collecting tab 15B protrudes to the other side in the lateral direction of the battery 1.

[0017] In the internal cavity 10, the electrode group 2 is retained (impregnated) with an electrolytic solution (not shown). The electrolytic solution may be a nonaqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent, or may be an aqueous electrolytic solution such as an aqueous solution. Instead of the electrolytic solution, a gel electrolyte or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte is interposed between the positive electrode 13A and the negative electrode 13B in the electrode group, instead of a separator. In this case, the solid electrolyte electrically insulates the positive electrode 13A from the negative electrode 13B.

[0018] In the battery 1, a pair of electrode terminals 16 are attached to the outer surface of the lid member 6. The pair of electrode terminals 16 are exposed to the outside of the battery 1 and are disposed on the outer surface of the lid member 6. Therefore, the pair of electrode terminals 16 are installed in the exterior member 3. The pair of electrode terminals 16 are formed from a conductive material such as metal. One of the pair of electrode terminals 16 is a positive electrode terminal 16A of the battery 1. The other of the pair of electrode terminals 16 other than the positive electrode terminal 16A is a negative electrode terminal 16B of the battery 1. On the outer surface of the lid member 6, an insulating member 18 is provided between each of the pair of electrode terminals 16 and the lid member 6. Each of the pair of electrode terminals 16 is electrically insulated from the exterior container 5 and the lid member 6 by the insulating member 18.

[0019] A pair of conductive members 20 are disposed in the internal cavity 10 of the outer container 5. One of the pair of conductive members 20 is a positive conductive member 20A. The other of the pair of conductive members 20 is a negative conductive member 20B. The positive conductive member 20A forms at least a portion of the electrical path between the positive current collector tab 15A and the positive terminal 16A. Therefore, the positive current collector tab 15A is electrically connected to the positive terminal 16A via at least the positive conductive member 20A. The negative conductive member 20B forms at least a portion of the electrical path between the negative current collector tab 15B and the negative terminal 16B. Therefore, the negative current collector tab 15B is electrically connected to the negative terminal 16B via at least the negative conductive member 20B. Each of the conductive members 20 is formed from a conductive material such as a metal. Examples of conductive materials for the conductive members 20 include aluminum, stainless steel, copper, and iron. The pair of conductive members 20 is, for example, a pair of leads.

[0020] Each of the pair of current collector tabs 15 has a plurality of stacked strip portions. During the manufacture of the battery 1, the plurality of strip portions of each of the pair of current collector tabs 15 are bundled together before electrically connecting each of the current collector tabs 15 to a corresponding one of the electrode terminals 16. Therefore, each of the current collector tabs 15 has the bundled plurality of strip portions electrically connected to a corresponding one of the pair of electrode terminals 16 via a corresponding one of the pair of conductive members 20. Specifically, the bundled plurality of strip portions of the positive electrode current collector tab 15A are electrically connected to the positive electrode terminal 16A via the positive electrode conductive member 20A. The bundled plurality of strip portions of the negative electrode current collector tab 15B are electrically connected to the negative electrode terminal 16B via the negative electrode conductive member 20B. In the example shown in FIG. 1 , each of the pair of conductive members 20 has a pair of legs and is bifurcated. At least one of the pair of legs of each conductive member 20 is connected to the bundled strip-shaped portions of the corresponding one of the current collecting tabs 15. In another example, each conductive member 20 may be configured to have only one leg. In this case, the only leg of each conductive member 20 is connected to the bundled strip-shaped portions of the corresponding one of the current collecting tabs 15.

[0021] 1, a gas release valve 23 and a liquid filling port (not shown) are formed in the lid member 6. Then, a sealing plate 25 that closes the liquid filling port is welded to the outer surface of the lid member 6. Note that the gas release valve 23, the liquid filling port, etc. do not necessarily have to be provided in the battery 1. Furthermore, in the internal cavity 10 of the outer container 5, the current collecting tabs (15A and 15B) and the pair of conductive members 20 are electrically insulated from the outer container 5 by one or more insulating members (not shown).

[0022] Next, the joint 31 formed on each of the pair of current collecting tabs 15 of the electrode group 2 will be described. Specifically, as shown in FIG. 1 , a positive electrode side joint 31A is formed on the positive electrode current collecting tab 15A, and a negative electrode side joint 31B is formed on the negative electrode current collecting tab 15B. Here, the positive electrode side joint 31A is configured similarly to the negative electrode side joint 31B. Therefore, the same description of the configuration as that of the positive electrode side joint 31A also applies to the negative electrode side joint 31B. Therefore, hereinafter, the positive electrode current collecting tab 15A will be described as the current collecting tab 15, and the positive electrode side joint 31A will be described as the joint 31, and descriptions of the negative electrode current collecting tab 15B and the negative electrode side joint 31B will be omitted. Note that the joint 31 does not necessarily have to be formed on both of the pair of current collecting tabs 15. That is, the joint 31 may be formed on only one of the pair of current collecting tabs 15, or on both of the pair of current collecting tabs 15.

[0023] FIG. 2 is a schematic diagram showing a portion of an electrode group 2 housed in a battery 1 according to an embodiment. Similar to FIG. 1, the height, width, and depth directions of the battery 1 are defined in FIG. 2 as well. Furthermore, in the joint 31, the first direction (indicated by arrows Z3 and Z4) coincides with or substantially coincides with the height direction of the battery 1. The second direction (indicated by arrows Y3 and Y4) intersects (is perpendicular or substantially perpendicular to) the first direction. The third direction (indicated by arrows X3 and X4) intersects (is perpendicular or substantially perpendicular to) both the first and second directions. In this embodiment, the second direction coincides with or substantially coincides with the width direction of the battery 1. The third direction coincides with or substantially coincides with the depth direction of the battery 1. Furthermore, the third direction is the depth direction of the joint 31.

[0024] The joint 31 is formed, for example, at the connection between the current collecting tab 15 and a conductive member (not shown in FIG. 2 ). This joins the current collecting tab 15 to the conductive member and electrically connects the current collecting tab 15 and the conductive member. The joint 31 is formed, for example, by a horn (ultrasonic horn) used in ultrasonic bonding. As described above, the electrode group 2 of this embodiment is a wound-type electrode group. Therefore, the ultrasonic horn is placed at an appropriate position on the current collecting tab 15 from the lateral outside of the battery 1. The ultrasonic horn presses the current collecting tab 15 against the conductive member and deforms the current collecting tab 15. The ultrasonic horn forms the joint 31 by indenting the current collecting tab 15 toward the conductive member in the depth direction of the battery 1 and applying ultrasonic vibrations. The joint 31 is preferably formed from the current collecting tab 15 to the conductive member along the depth direction of the battery 1 (the depth direction of the joint 31). As a result, the joint 31 is formed in the depth direction across both the current collecting tab 15 and the conductive member, which increases the bonding strength between the current collecting tab 15 and the conductive member, thereby reducing the occurrence of malfunctions in the battery 1 caused by poor bonding between the current collecting tab 15 and the conductive member.

[0025] FIG. 3 is a schematic diagram showing an enlarged view of the joint 31 formed on the current collecting tab 15. Similar to FIG. 2, the first, second, and third directions of the joint 31 are defined in FIG. 3 as well. As shown in FIG. 3, the joint 31 of this embodiment includes a plurality of recesses and spacing portions 32 formed between the recesses. The joint 31 of this embodiment includes six recesses 311 to 316. The six recesses 311 to 316 are formed close to one another. Specifically, the joint 31 includes a plurality of recesses aligned along the first direction of the joint 31, and a plurality of recesses aligned along the second direction of the joint 31. Therefore, the joint 31 includes a plurality of recesses aligned along at least one of the first and second directions of the joint 31. Hereinafter, the recesses 311 to 316 will also be referred to as the first to sixth recesses, respectively.

[0026] In the bonding portion 31 of this embodiment, the first recess 311 and the second recess 312, the third recess 313 and the fourth recess 314, the fifth recess 315 and the sixth recess 316 are aligned along the second direction of the bonding portion 31 and are formed adjacent to each other. Furthermore, the first recess 311, the third recess 313 and the recess 315 are aligned along the first direction of the bonding portion 31, and the first recess 311 and the third recess 313, and the third recess 313 and the fifth recess 315 are formed adjacent to each other. Similarly, the second recess 312, the fourth recess 314 and the sixth recess 316 are aligned along the first direction of the bonding portion 31, and the second recess 312 and the fourth recess 314, and the fourth recess 314 and the sixth recess 316 are formed adjacent to each other. In this way, in the joint 31, three recesses are formed side by side in the first direction of the joint 31, and two recesses are formed side by side in the second direction of the joint 31, so that six recesses are formed close to each other.

[0027] The separating portion 32 includes a first separating portion 321 and a second separating portion 322. The first separating portion 321 is formed between two recesses adjacent to each other along the first direction of the joining portion 31. Specifically, the first separating portion 321 is formed between the first recess 311 and the third recess 313, the third recess 313 and the fifth recess 315, the second recess 312 and the fourth recess 314, and the fourth recess 314 and the sixth recess 316. The second separating portion 322 is formed between two recesses adjacent to each other along the second direction of the joining portion 31. Specifically, the second separating portion 322 is formed between the first recess 311 and the second recess 312, the third recess 313 and the fourth recess 314, and the fifth recess 315 and the sixth recess 316.

[0028] The first separation portion 321 between the first recess 311 and the third recess 313, and the first separation portion 321 between the second recess 312 and the fourth recess 314 are not or hardly misaligned in the first direction of the joint 31. Similarly, the first separation portion 321 between the third recess 313 and the fifth recess 315, and the first separation portion 321 between the fourth recess 314 and the sixth recess 316 are not or hardly misaligned in the first direction of the joint 31. The second separation portion 322 between the first recess 311 and the second recess 312, the second separation portion 322 between the third recess 313 and the fourth recess 314, and the second separation portion 322 between the fifth recess 315 and the sixth recess 316 are not or hardly misaligned in the first direction of the joint 31 relative to each other. 2 Therefore, in the joint 31, the plurality of first spaced portions 321 form linear or substantially linear spaced portions along the second direction of the joint 31, and the plurality of second spaced portions 322 form linear or substantially linear spaced portions along the first direction of the joint 31.

[0029] FIG. 4 is a schematic diagram showing one of the recesses 311 to 316 formed in the current collecting tab 15. FIG. 5 is a cross-sectional view taken along line VV of the joint 31 shown in FIG. 3. FIG. 6 is a cross-sectional view taken along line VI-VI of the joint 31 shown in FIG. 3. In this embodiment, the recesses 311 to 316 are configured in the same manner. Therefore, the same description of the configuration as for the recess 311 also applies to the recesses 312 to 316. Note that in FIGS. 4 to 6, as in FIGS. 2 and 3, a first direction, a second direction, and a third direction are defined.

[0030] As shown in FIG. 4 , the recess 311 has two pairs of edges E1 and E2, two pairs of inclined surfaces 33 and 34, and a bottom 35. The two pairs of edges E1 and E2 include a pair of edges E1 and a pair of edges E2. The pair of edges E1 are spaced apart from each other in the second direction of the joint 31. One of the pair of edges E1 forms one edge of the recess 311 in the second direction of the joint 31, and the other of the pair of edges E1 forms the other edge of the recess 311 in the second direction of the joint 31. The pair of edges E1 extends along the first direction of the joint 31 between the pair of edges E2. The pair of edges E2 are also spaced apart from each other in the first direction of the joint 31. One of the pair of edges E2 forms one edge of the recess 311 in the first direction of the joint 31, and the other of the pair of edges E2 forms the other edge of the recess 311 in the first direction of the joint 31. The pair of edges E2 extend along the second direction of the joint 31 between the pair of edges E1. Thus, the two pairs of edges E1, E2 form the peripheral edge E of the recess 311.

[0031] The two pairs of inclined surfaces 33, 34 are arranged adjacent to each other. Each of the pair of inclined surfaces 33 is formed in the second direction of the joint 31 from the edge E1 that forms the end of the inclined surface 33 to the bottom 35. Each of the ends E3 of the pair of inclined surfaces 33 is formed closer to the bottom 35 than the edge E1 in the second direction as it moves toward the center of the joint 31 in the first direction. The pair of inclined surfaces 33 are formed so that they move toward one side of the joint 31 in the third direction, i.e., toward the side where the conductive member 20 is located in the third direction of the joint 31 (depth direction of the battery 1), as they move toward the bottom 35.

[0032] Each of the pair of inclined surfaces 34 is formed from an edge E2 forming an end of the inclined surface 34 to a bottom 35 in the first direction of the joint 31. Each of the ends E3 of the pair of inclined surfaces 34 becomes gradually narrower as it approaches the center of the joint 31 in the second direction. 1It is formed on the bottom 35 side with respect to the edge E2 in the direction of .

[0033] Since the two pairs of inclined surfaces 33 and 34 are formed in this way, the two pairs of inclined surfaces 33 and 34 surround the bottom 35 from the outer peripheral side. As shown in FIGS. 4 to 6, the extension surfaces of the two pairs of inclined surfaces 33 and 34 intersect at the intersection point DP. In the present embodiment, the pair of inclined surfaces 33 have the same or substantially the same shape as each other, and the pair of inclined surfaces 34 have the same or substantially the same shape as each other. Specifically, the pair of inclined surfaces 33 and the pair of inclined surfaces 34 are each triangular or substantially triangular. Note that a plurality of intersection points DP may be formed in the recess 311. That is, the extension surfaces of the pair of inclined surfaces 33 and the extension surfaces of the pair of inclined surfaces 34 may intersect at a plurality of points.

[0034] As shown in FIGS. 3 and 4, in the recess 311, let the dimension between both ends of the recess 311 in the second direction of the joint 31 be wa, and the dimension between both ends of the recess 311 in the first direction of the joint 31 be wb. At this time, the dimension wa is smaller than the dimension wb. That is, wa < wb. Therefore, the recess 311 is formed in a rectangular or substantially rectangular shape that is long in the first direction of the joint 31 when viewed from one side in the third direction of the joint 31. At this time, the dimension wa coincides with or substantially coincides with the length of the pair of edges E2, and the dimension wb coincides with or substantially coincides with the length of the pair of edges E1. Also, it is preferable that the dimension wa is 0.2 times or more and 0.8 times or less with respect to the dimension wb.

[0035] Note that the shape of the recess 311 is not limited to the shape shown in FIGS. 3 and 4. The shape of the recess 311 may be any shape that satisfies the condition that the dimension wa is smaller than the dimension wb. For example, when viewed from one side in the third direction of the joint 31, the shape of the recess 311 may be an ellipse, a triangle, or a trapezoid. In these cases, the shape of the recess 311 may be a frustum of a cone, a frustum of a triangular pyramid, or a frustum of a quadrangular pyramid.

[0036] Also, in any of the recesses 311 to 316, when the dimension wa along the second direction and the dimension wb along the first direction are considered, the dimension wa is smaller than the dimension wb. In the present embodiment, since the recesses 311 to 316 are formed in the same or substantially the same shape, the dimension wa is the same or substantially the same in any of the recesses 311 to 316, and the dimension wb is the same or substantially the same in any of the recesses 311 to 316.

[0037] As described above, the recesses 311 to 316 are formed in a plurality in the second direction of the joint portion 31 and also in a plurality in the first direction of the joint portion 31. Here, as shown in FIG. 3 and the like, in the joint portion 31, the dimension between both ends of the joint portion 31 in the second direction of the joint portion 31 is WA, and the dimension between both ends of the joint portion 31 in the first direction of the joint portion 31 is WB. At this time, the dimension WA is smaller than the dimension WB. That is, WA < WB. In one example, the dimension WA is 0.5 mm or more and 5.0 mm or less. Specifically, in the joint portion 31, the recesses 311 to 316 are formed in two side by side in the second direction of the joint portion 31. Therefore, the dimension WA in the second direction of the joint portion 31 is larger than twice the dimension wa along the second direction of each of the recesses 311 to 316. That is, WA > 2×wa. Also, in the joint portion 31, the recesses 311 to 316 are formed in three side by side in the first direction of the joint portion 31. Therefore, the dimension WB in the first direction of the joint portion 31 is larger than three times the dimension wb along the first direction of each of the recesses 311 to 316. That is, WB > 3×wb.

[0038] From these dimensional relationships, the dimension along the first direction in the first separation portion 321 is half of the difference between WB and three times wb, i.e., (WB - 3×wb) / 2. Also, the dimension along the second direction in the second separation portion 322 is the difference between WA and twice wa, i.e., WA - 2×wa. Note that the dimension along the first direction in the first separation portion 321 does not have to be the same for all the plurality of first separation portions 321. However, in the plurality of first separation portions 321 arranged along the first direction of the joint portion 31, the sum of the dimensions along the first direction of the joint portion 31 is WB - 3×wb. For example, the sum of the dimensions along the first direction of both the first separation portion 321 between the recess 311 and the recess 313, and the first separation portion 321 between the recess 313 and the recess 315 is WB - 3×wb. And the sum of the dimensions along the first direction of both the first separation portion 321 between the recess 312 and the recess 314, and the first separation portion 321 between the recess 314 and the recess 316 is WB - 3×wb.

[0039] These dimensional relationships hold regardless of the number of the plurality of recesses. For example, in the joint portion 31, assume that m (m > 1) recesses are formed in the second direction of the joint portion 31 and n (n > 1) recesses are formed in the first direction of the joint portion 31. At this time, the joint portion 31 includes m×n recesses. Also at this time, in the joint portion 31, WA < WB is satisfied. And WA of the joint portion 31 is larger than m times wa of the recess, and WB of the joint portion 31 is larger than n times wb of the recess. That is, WA > m×wa and WB > n×wb. Also, the dimension along the first direction in the first separation portion 321 is 1 / (n - 1) of the difference between WB of the joint portion 31 and n times wb of the recess, i.e., (WB - n×wb) / (n - 1). Also, the dimension along the second direction in the second separation portion 322 is 1 / (m - 1) of the difference between WA of the joint portion 31 and m times wa of the recess, i.e., (WA - m×wa) / (m - 1).

[0040] However, as long as the sum of the dimensions of the joining portion 31 along the first direction of the multiple first separated portions 321 aligned in the first direction is WB-n×wb, the dimensions of each of the first separated portions 321 are not particularly limited. Also, as long as the sum of the dimensions of the joining portion 31 along the second direction of the multiple second separated portions 322 aligned in the second direction of the joining portion 31 is WA-m×wa, the dimensions of each of the second separated portions 322 are not particularly limited.

[0041] The same applies as above when the dimensions of the multiple recesses are different from each other. Even in this case, the dimension between both ends of each recess in the second direction is smaller than the dimension between both ends in the first direction. If the dimensions between both ends of each of the multiple recesses in the second direction are wa1, wa2, ..., wan, and the dimensions between both ends of each of the multiple recesses in the first direction are wb1, wb2, ..., wbm, then WA > wa1 + wa2 + ... + wan, and WB > wb1 + wb2 + ... + wbm.

[0042] When m = 1 and n > 1, that is, assuming that one recess is formed in the second direction of the joint portion 31 and n (n > 1) recesses are formed in the first direction of the joint portion 31. At this time, the joint portion 31 includes n recesses. Also at this time, in the joint portion 31, WA < WB is satisfied. However, since one recess is formed in the second direction of the joint portion 31, the second separation portion 322 is not formed. Therefore, in the joint portion 31, WA = wa. Further, when m > 1 and n = 1, that is, assuming that one recess is formed in the first direction of the joint portion 31 and m (m > 1) recesses are formed in the second direction of the joint portion 31. At this time, the joint portion 31 includes m recesses. Also at this time, in the joint portion 31, WA < WB is satisfied. However, since one recess is formed in the first direction of the joint portion 31, the first separation portion 321 is not formed. Therefore, in the joint portion 31, WB = wb. Also, when m = 1 and n = 1, that is, even when one recess is formed in the joint portion 31, in the joint portion 31, WA < WB is satisfied. However, since one recess is formed in the joint portion 31, the first separation portion 321 and the second separation portion 322 are not formed. Therefore, in the joint portion 31, WA = wa and WB = wb.

[0043] As shown in FIGS. 5 and 6 , the current collecting tab 15 has a surface S1 and a surface S2. The surface S1 faces the side where the conductive member 20 is located in the third direction of the joint 31. The surface S2 faces the opposite side from the surface S1 (opposite the conductive member 20) in the third direction of the joint 31. The surface S1 of the current collecting tab 15 contacts the conductive member 20. As shown in FIG. 5 , in the recess 311, a pair of inclined surfaces 33 are inclined with respect to the surface S1 and the surface S2. The pair of inclined surfaces 33 are formed beyond the surface S1 of the current collecting tab 15 in the third direction of the joint 31. The pair of inclined surfaces 33 are formed from the current collecting tab 15 to the conductive member 20. That is, the pair of inclined surfaces 33 are formed from the surface S2 of the current collecting tab 15 to the inside of the conductive member 20. Furthermore, as shown in FIG. 6 , in the recess 311, a pair of inclined surfaces 34 are inclined with respect to the surface S1 and the surface S2. The pair of inclined surfaces 34 is formed beyond the surface S1 of the current collecting tab 15 in the third direction of the joint 31. The pair of inclined surfaces 34 is formed from the current collecting tab 15 to the conductive member 20. That is, the pair of inclined surfaces 34 is formed from the surface S2 of the current collecting tab 15 to the inside of the conductive member 20. Because two pairs of inclined surfaces 33, 34 are formed in this way, the intersection DP is located inside the conductive member 20 in the third direction of the joint 31. That is, the intersection DP is formed on the side of the surface S1 where the conductive member 20 is located in the third direction of the joint 31.

[0044] The recess distance d of the recess 311 along the third direction is a virtual distance from the surface S2 of the current collecting tab 15 to the intersection point DP. As shown in FIGS. 5 and 6 , in this embodiment, the intersection point DP is formed in the conductive member 20, and therefore the recess distance d of the recess 311 is greater than the thickness of the current collecting tab 15 (i.e., the dimension of the joint 31 along the third direction from the surface S1 to the surface S2). Furthermore, the intersection point DP does not extend beyond the conductive member 20 in the third direction. Therefore, the recess distance d of the recess 311 is smaller than the total thickness of the current collecting tab 15 and the conductive member 20.

[0045] The recess distance d of the recess 311 is greater than half the wa of the recess 311. It is preferable that the recess distance d satisfy the relationship d>wa / 2. Furthermore, since the pair of inclined surfaces 33 are formed to have the same or substantially the same shape as described above, the intersection point DP is located at the center of the recess 311 in the second direction of the joint 31. Therefore, the recess 311 is formed symmetrically with respect to a plane that passes through the intersection point DP and is perpendicular or substantially perpendicular to the second direction. Therefore, as shown in FIG. 5 , the angle θ1 between the pair of inclined surfaces 33 is preferably an acute angle. The angle θ1 between the pair of inclined surfaces 33 is preferably smaller than 45°. Furthermore, the angle θ1 between the pair of inclined surfaces 33 is preferably greater than 30°. That is, it is even more preferable that the angle θ1 between the pair of inclined surfaces 33 is greater than 30° and smaller than 45°. Forming the angle θ1 between the pair of inclined surfaces 33 in this manner can reduce the occurrence of bonding defects, such as breakage of the current collecting tab 15, when the current collecting tab 15 is bonded to the conductive member 20. By forming the angle θ1 at an acute angle in this way, the recess distance d can be increased while maintaining the dimension wa small in the recess. Therefore, the joint 31 can be formed while maintaining the volume of the portion surrounded by the recess small, thereby reducing the amount of burrs generated.

[0046] As shown in FIG. 6 , even in the cross section taken along line VI-VI, the recess distance d of the recess 311 is the distance from the surface S2 of the current collecting tab 15 to the intersection point DP. Because the pair of inclined surfaces 34 are formed to have the same or substantially the same shape as described above, the intersection point DP is located at the center of the recess 311 in the first direction of the joint 31. Therefore, the recess 311 is formed symmetrically with respect to a plane passing through the intersection point DP, which is perpendicular or substantially perpendicular to the first direction. In this case, the angle θ2 between the pair of inclined surfaces 34 is not particularly limited. However, the angle θ2 between the pair of inclined surfaces 34 is determined under the conditions that wb is greater than wa and the angle θ1 between the pair of inclined surfaces 33 is an acute angle. Therefore, it is preferable that the angle θ2 between the pair of inclined surfaces 34 is greater than the angle θ1 between the pair of inclined surfaces 33. Furthermore, it is more preferable that the angle θ2 between the pair of inclined surfaces 34 is an obtuse angle.

[0047] When the dimensions of the recesses are different from each other, a recess distance d is defined for each recess, that is, the recess distance d is preferably greater than half the dimension between both ends of the recess in the second direction.

[0048] As shown in FIGS. 4 and 5 , burrs BR are formed on the peripheral edge E of the recess 311. The burrs BR are formed when the current collecting tab 15 is recessed by the ultrasonic horn. In this embodiment, the ultrasonic horn is pressed against the current collecting tab 15 while vibrating in the first direction of the joint 31, thereby forming the recess 311. At this time, the current collecting tab 15 is pressed toward the side where the conductive member 20 is located by the ultrasonic horn, and vibrations along the first direction of the joint 31 are applied to the current collecting tab 15. Therefore, the ultrasonic horn vibrating along the extension direction of the pair of edges E1 forms the pair of edges E1 on the current collecting tab 15. The ultrasonic horn vibrating in a direction intersecting (perpendicular or approximately perpendicular to) the pair of edges E2 formed on the current collecting tab 15 forms the pair of edges E2 on the current collecting tab 15. Therefore, the amount of remaining burrs BR differs between the pair of edges E1 and the pair of edges E2. In this embodiment, the amount of remaining burrs is greater in the region adjacent to the recess 311 from the first direction than in the region adjacent to the recess 311 from the second direction. The region adjacent to the recess 311 from the first direction is, for example, the region adjacent to the pair of edges E2 from the first direction. The region adjacent to the recess 311 from the second direction is, for example, the region adjacent to the pair of edges E1 from the second direction.

[0049] 4 and 5 do not show the burrs BR formed on the pair of edges E1. Furthermore, the burrs BR do not have to be formed over the entire length of the pair of edges E2. That is, the burrs BR may be formed only on a portion of the pair of edges E2. In the recesses 312 to 316, as in the recess 311, burrs BR are formed on the peripheral edge E, and the amount of burrs BR remaining on the pair of edges E2 is greater than that on the pair of edges E1. Therefore, in the joint 31 of this embodiment, the dimensions of the edge where the amount of burrs BR remaining is greater are smaller than the dimensions of the edge where the amount of burrs BR remaining is smaller.

[0050] As described above, burrs BR are formed on the peripheral edges E of the recesses 311-316. As described above, the recesses 311-316 are formed by an ultrasonic horn vibrating in a vibration direction along the first direction of the joint 31. At this time, as shown in FIGS. 3 and 6, the amount of burrs BR remaining on the edge E2 (referred to as the outermost edge EO) located on the outermost side of the joint 31 in the first direction is greater than that on the other edges E1 and E2. The reason for this difference in the amount of burrs is presumably that burrs formed on edges other than the outermost edge EO are peeled off by pressing and vibrating the current collecting tab 15. Specifically, in the joint 31 of this embodiment, of the pair of edges E2 of the recess 311, the edge E2 located on the outer side of the joint 31 in the first direction is the outermost edge EO. Similarly, of the pair of edges E2 of the recess 312, the edge E2 located on the outer side of the joint 31 in the first direction is the outermost edge EO. Of the pair of edges E2 of the recess 315, the edge E2 located on the outside of the joint 31 in the first direction is the outermost edge EO. Of the pair of edges E2 of the recess 316, the edge E2 located on the outside of the joint 31 in the first direction is the outermost edge EO.

[0051] As described above, in this embodiment, the joint 31 connects the current collecting tab 15 and the conductive member 20. The joint 31 includes a recess and a peripheral edge E. The recess is recessed toward the side of the current collecting tab 15 where the conductive member 20 is located, and the second dimension wa between both ends in the second direction is smaller than the first dimension wb between both ends in the first direction. The peripheral edge E surrounds the recess, and the amount of burrs remaining is greater in the area adjacent to the recess from the first direction than in the area adjacent to the recess from the second direction. By forming the joint 31 in this manner, when the joint 31 is formed using an ultrasonic horn vibrating in the first direction, the dimensions of the area where more burrs BR remain can be reduced compared to other areas. This reduces the total amount of burrs generated when forming the joint 31.

[0052] In this embodiment, the joint 31 is preferably formed from the current collecting tab 15 to the conductive member 20. By forming the joint 31 in this manner, the joint 31 is formed on both sides of the surface S1. This allows the current collecting tab 15 and the conductive member 20 to be sufficiently joined together.

[0053] In this embodiment, it is preferable that the joint 31 has multiple recesses, each of which has one peripheral edge. In the joint 31 formed from a collection of multiple recesses, it is preferable that the fourth dimension WA between both ends in the second direction is smaller than the third dimension WB between both ends in the first direction. By forming multiple recesses in this manner, the joint 31 is formed into a shape that is elongated in the first direction. Therefore, when forming the joint 31 using an ultrasonic horn that vibrates in the first direction, for example, the dimensions of the edge where more burrs BR remain than other edge portions can be made smaller. This reduces the total amount of burrs generated when forming the joint 31.

[0054] In this embodiment, it is preferable that the amount of burrs remaining is greater in the outermost portion of the joint 31 in the first direction among the peripheries of the multiple recesses than in other portions. This makes it possible to reduce the amount of burrs remaining in other portions for the reasons described above, and also to reduce the amount of burrs remaining throughout the entire joint 31. Therefore, it is possible to reduce the amount of burrs that are generated when forming the joint 31.

[0055] In this embodiment, the second dimension wa is preferably 0.2 to 0.8 times the first dimension wb. By forming the recess 311 with such dimensions, the dimension of the recess 311 in a direction intersecting (perpendicular or substantially perpendicular to) the vibration direction can be reduced during joining using an ultrasonic horn that vibrates along the first direction of the joining portion 31. In particular, when the second dimension wa is 0.2 times or more the first dimension wb, the second dimension wa is not too small, reducing the possibility of cutting the current collecting tab 15 to be joined. Furthermore, when the second dimension wa is 0.8 times or less the first dimension wb, a sufficient dimensional difference between the first and second directions can be ensured, thereby fully achieving the effects of this embodiment.

[0056] In this embodiment, the recess distance d of the recess is preferably greater than half the second dimension wa. This allows the recess to be formed small while maintaining the recess distance d large enough for bonding when the recess is formed using an ultrasonic horn vibrating in the first direction. Since the recess size can be reduced, the size of the bonded portion 31 can also be reduced. This reduces the total amount of burrs that occur when forming the bonded portion 31.

[0057] (Example) In the example, the current collecting tab 15 and the conductive member 20 were ultrasonically bonded together using an ultrasonic horn to form a joint 31 having the recess of the embodiment. In the comparative example, the current collecting tab 15 and the conductive member 20 were ultrasonically bonded together using an ultrasonic horn by forming a joint 31 having a recess whose edges E1 and E2 had the same dimensions. In both the example and the comparative example, the number of recesses was one row in the second direction of the joint 31 and three rows in the first direction of the joint 31. Therefore, a total of three recesses were formed at once in each example and comparative example. In both the example and comparative example, the vibration direction of the ultrasonic horn was approximately aligned with the first direction of the joint 31. Furthermore, five tests were performed in both the example and comparative example. The values ​​of θ1, θ2, wa, and wb for each recess were set as shown in the table below.

[0058] [Table 1]

[0059] The results are shown in Figures 7 to 9. The vertical axis in Figure 7 represents the bonding strength, the vertical axis in Figure 8 represents the bonding time, and the vertical axis in Figure 9 represents the bonding energy. The units of the vertical axes in Figures 7 to 9 are arbitrary units corresponding to the respective items. As shown in Figure 7, the bonding strength of the recesses in the Example varies less than the bonding strength of the recesses in the Comparative Example. As shown in Figure 8, the bonding time of the recesses in the Example varies less than the bonding time of the recesses in the Comparative Example. As shown in Figure 9, the bonding energy of the recesses in the Example varies less than the bonding energy of the recesses in the Comparative Example. These results are thought to be due to the fact that the generation of burrs in the recesses in the Example was reduced, thereby improving the stability of the bonding when performing a single bonding (improving the reproducibility of the bonding). Therefore, it was demonstrated that the reduction in the generation of burrs improved the bonding ability of the members by the recesses.

[0060] (Variation) In one modification, the bottom 35 of at least one of the recesses 311-316 may be formed at the same position as the intersection point DP in the third direction. In this case, the bottom 35 coincides with or substantially coincides with the intersection point DP. In this modification, the two pairs of inclined surfaces 33, 34 have the same configuration as the aforementioned embodiment. Therefore, in this modification, the intersection point DP becomes the bottom 35, and the shape of the recess is, for example, a triangular pyramid, a quadrangular pyramid, or a cone. The recess distance d is the depth of the recess. In this modification, as in any of the aforementioned embodiments, the peripheral edge E surrounds the recess, and the amount of remaining burrs is greater in the area adjacent to the recess from the first direction than in the area adjacent to the recess from the second direction. As a result, the battery 1 of this modification also achieves the same effects as the aforementioned embodiment. FIG. 10 is a cross-sectional view schematically illustrating a modified example of the battery 1 according to the embodiment, taken along a cross section perpendicular to the depth direction of the battery 1. The height, width, and depth directions of the battery 1 are also defined for the battery 1 shown in FIG. 10. However, in the battery 1 of this modified example, at the joint 31, the first direction (indicated by arrows Y5 and Y6) coincides or substantially coincides with the width direction of the battery 1. The second direction (indicated by arrows Z5 and Z6) coincides or substantially coincides with the height direction of the battery 1. The third direction coincides or substantially coincides with the depth direction of the battery 1.

[0061] In the battery 1 of this modified example, a pair of current collecting tabs 15 protrude from the same side relative to each other. The pair of current collecting tabs 15 protrude from the electrode group 2 on the side where the pair of electrode terminals 16 are located in the height direction of the battery 1. In this modified example, the pair of current collecting tabs 15 do not contact each other. Specifically, the positive electrode current collecting tab 15A protrudes from the electrode group 2 on the side where the positive electrode terminal 16A is located. The negative electrode current collecting tab 15B protrudes from the electrode group 2 on the side where the negative electrode terminal 16B is located. In this case, as shown in FIG. 10 , similar to any of the above-described embodiments, the peripheral edge E surrounds the recess, and the amount of remaining burrs is greater in the area adjacent to the recess from the first direction than in the area adjacent to the recess from the second direction. This allows the battery 1 of this modified example to achieve the same effects as the above-described embodiments.

[0062] The exterior member of the battery 1 is not limited to a configuration formed from the exterior container 5 and the lid member 6. In one variation, as in Reference Document 1 (WO 2016 / 204147), the exterior portion may be formed from a first exterior member and a second exterior member made of metal. In this case, the first exterior member has a bottom wall and a peripheral wall, and a flange protrudes from the end of the peripheral wall opposite the bottom wall toward the outer periphery of the first exterior member. The second exterior member is attached to the flange of the first exterior member. In another variation, the exterior portion of the battery may be formed from a laminate film with a three-layer structure in which a metal layer is sandwiched between resin layers. In any of the variations, the joint 31 is formed on the current collecting tab 15 in the same manner as in any of the above-mentioned embodiments.

[0063] Fig. 11 is a perspective view schematically illustrating an example of a battery according to a modified embodiment. Similar to Fig. 1, Fig. 11 also defines the height, width, and depth directions of the battery 1, as well as the first, second, and third directions of the joint 31. Fig. 12 is a cross-sectional view of the joint 31 shown in Fig. 11, taken along a cross section perpendicular or substantially perpendicular to the first direction. Fig. 13 is a cross-sectional view of the joint 31 shown in Fig. 11, taken along a cross section perpendicular or substantially perpendicular to the second direction. Similar to Fig. 11, Figs. 12 and 13 also define the height, width, and depth directions of the battery 1, as well as the first, second, and third directions of the joint 31.

[0064] In the modified example shown in FIGS. 11 to 13, the conductive member 20 is formed from multiple components. In the modified example shown in FIGS. 11 to 13, a backup lead 21 as a component of the conductive member 20 is attached to the current collecting tab 15. The positive electrode backup lead 21A is attached to the positive electrode current collecting tab 15A, and the negative electrode backup lead 21B is attached to the negative electrode current collecting tab 15B. The backup lead 21 has a surface S3. The surface S3 faces the opposite side of the joint 31 from the surface S1 (opposite the current collecting tab 15 side) in the third direction, and forms the surface of the joint 31. A pair of inclined surfaces 33 is formed from the surface S3 of the backup lead 21 to the interior of the conductive member 20, and a pair of inclined surfaces 34 is formed from the surface S3 of the backup lead 21 to the interior of the conductive member 20. In this modified example, the recess distance d is the distance from the surface S3 of the backup lead 21 to the intersection DP.

[0065] In this modification, the intersection point DP may be located closer to the conductive member 20 than the surface S1 of the current collecting tab 15 in the third direction. The intersection point DP may be located on the backup lead 21 on the side that contacts the conductive member 20 in the third direction. In this case, the two pairs of inclined surfaces 33, 34 are formed in the third direction from the backup lead 21 on the side that contacts the current collecting tab 15 to the vicinity of the backup lead 21 on the side that contacts the conductive member 20. In this case, as shown in FIGS. 11 to 13 , the peripheral edge E surrounds the recess, and the amount of burrs remaining is greater in the area adjacent to the recess from the first direction than in the area adjacent to the recess from the second direction. This allows the battery 1 of this modification to achieve the same effects as the above-described embodiment.

[0066] According to at least one of these embodiments, a joint connecting a current collecting tab and a conductive member of a battery includes a recess and a peripheral edge. The recess is recessed toward the side of the current collecting tab where the conductive member is located, and has a first dimension between both ends in a first direction that is smaller than a second dimension between both ends in a second direction. The peripheral edge surrounds the recess, and a portion adjacent to the recess in the first direction has a larger amount of burr remaining than a portion adjacent to the recess in the second direction. This makes it possible to provide a battery and a method for manufacturing a battery that can reduce the formation of burrs in the recess that joins the strip portion and the conductive member.

[0067] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. An exterior member; an electrode terminal installed on the exterior member; an electrode group housed in the internal cavity of the exterior member and having protruding current collecting tabs; a conductive member that electrically connects the electrode terminal and the current collecting tab; a joint portion connecting the current collecting tab and the conductive member; Equipped with The joint is a recess in the current collecting tab toward the side where the conductive member is located, the recess having a first dimension between both ends in a first direction that is smaller than a second dimension between both ends in a second direction that intersects the first direction; a peripheral portion surrounding the recess and adjacent to the recess from the first direction, in which a larger amount of burrs remain than in a portion adjacent to the recess from the second direction; battery.

2. The joint is formed from the current collecting tab to the conductive member. The battery of claim 1 .

3. the joint portion includes a plurality of recesses, and the peripheral portion is provided for each of the plurality of recesses; In the joint formed by an aggregate of the plurality of recesses, a fourth dimension between both ends in the second direction is smaller than a third dimension between both ends in the first direction. The battery according to claim 1 or 2.

4. the amount of burrs remaining is greater at an outermost portion of the joint in the first direction among the peripheral portions of the plurality of recesses than at other portions; The battery of claim 3.

5. The second dimension is 0.2 to 0.8 times the first dimension. The battery according to any one of claims 1 to 4.

6. a recessed distance of the recess is greater than half of the second dimension; The battery according to any one of claims 1 to 5.

7. Installing an electrode terminal on an exterior member; forming an electrode group in a state in which the current collecting tabs protrude; housing the electrode group in an internal cavity of the exterior member; forming a recess in the current collecting tab that is recessed toward a side where a conductive member is located, by using a horn that vibrates along a first direction, forming the recess in a state in which a second dimension between both ends in a second direction intersecting the first direction is smaller than a first dimension between both ends in the first direction; forming the recess recessed toward the conductive member in the current collecting tab to connect the current collecting tab to the conductive member, and electrically connecting the electrode terminal and the current collecting tab by the conductive member; A method for manufacturing a battery, comprising:

8. In forming the recess in the current collecting tab, the recess is recessed toward the side where the conductive member is located, forming a plurality of the recesses, forming a peripheral portion surrounding the recess, one for each of the plurality of recesses; the recesses are formed in a state in which a larger amount of burrs remain in portions formed on the outermost sides of the peripheral edge of the recesses in the first direction than in other portions of the peripheral edge; The method for manufacturing the battery according to claim 7 .

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