Battery, joining jig, joining device, and battery manufacturing method

Abstract

To provide a battery that can improve the bonding strength at the bonding portion when bonding a current collecting bundle portion of an electrode group to a lead, while suppressing inappropriate deformation of the bonding portion due to bonding.SOLUTION: A battery according to an embodiment includes an electrode group, a lead, a groove, and one or more recesses. The electrode group includes a current collecting bundle portion that protrudes toward one side in a longitudinal direction. The lead is joined to the current collecting bundle portion while being stacked on the current collecting bundle portion from one side of the electrode group in a thickness direction, which intersects the longitudinal direction. The groove is recessed to the groove bottom toward the side where the lead is located in the thickness direction at the bonding portion between the lead and the current collecting bundle portion, and does not protrude toward the side where the current collecting bundle portion protrudes in the longitudinal direction relative to the lead. Each of the one or more recesses is further recessed from the groove bottom toward the side where the lead is located.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a battery, a joining jig, a joining device, and a method for manufacturing a battery. [Background technology]

[0002] Batteries such as lithium-ion secondary batteries include an electrode group, which includes a positive electrode and a negative electrode. In the electrode group, each of the positive and negative electrodes includes a current collector, and the current collector forms a current collecting bundle portion in which multiple current collecting band portions are bundled. In the electrode group, the current collecting bundle portion protrudes to one side in the longitudinal direction, and in the battery, the current collecting bundle portion of the current collector is electrically connected to a terminal via a lead or the like. The current collecting bundle portion is joined to the lead by ultrasonic welding or the like, and in the battery, a joint portion between the current collecting bundle portion and the lead is formed.

[0003] In battery manufacturing, a current collecting bundle part is joined to a lead using a joining jig having one or more protrusions protruding from a base. To join the current collecting bundle part to the lead, the lead is stacked on the current collecting bundle part from one side in the thickness direction of the electrode group, and the joining target part, where the current collecting bundle part and the lead are stacked, is sandwiched between the joining jig and a stage. Then, with the joining target part sandwiched between the joining jig and the stage, the lead and the current collecting bundle part are joined by, for example, transmitting ultrasonic vibrations to the joining target part through the joining jig. While the joining target part is being joined, one or more protrusions of the joining jig are brought into contact with the joining target part from the side opposite the side where the leads are stacked. Therefore, in the joining portion where the lead and the current collecting bundle part are joined, a recess recessed toward the side where the lead is located is formed in each of the portions where one or more protrusions are in contact.

[0004] Furthermore, by joining the current collecting bundle part to the lead with the base part in contact with the part to be joined in addition to one or more protrusions, the joining strength at the joint is improved. In this case, at the joint part between the lead and the current collecting bundle part, the part where the base part is in contact has a groove bottom that is recessed toward the side where the lead is located, and each of the parts where one or more protrusions are in contact has a recess that is further recessed from the groove bottom toward the side where the lead is located.

[0005] Here, when bonding is performed with the base portion in contact with the part to be bonded in addition to one or more protrusions, depending on the position where the base portion is brought into contact, the contact area, etc., the bonded portion including the current collecting bundle portion may be inappropriately deformed, for example, by excessively expanding the bonded portion toward the side where the current collecting bundle portion protrudes. When bonding the current collecting bundle portion to the lead, it is required to improve the bond strength at the bonded portion while suppressing inappropriate deformation of the bonded portion due to bonding. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2013 / 105361 [Patent Document 2] International Publication No. 2022 / 180737 [Patent Document 3] Japanese Patent Publication No. 2023-24043 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a battery, a joining jig, a joining device, and a method for manufacturing a battery that can improve the joining strength at the joining portion when joining the current collecting bundle portion of the electrode group to the lead, while suppressing inappropriate deformation of the joining portion due to joining. [Means for solving the problem]

[0008] According to an embodiment, a battery includes an electrode group, a lead, a groove, and one or more recesses. The electrode group includes a current collecting bundle portion that protrudes toward one side in the length direction. The lead is conductive and is joined to the current collecting bundle portion while being stacked on one side of the electrode group in the thickness direction that intersects the length direction. The groove includes a groove bottom, and is recessed to the groove bottom toward the side where the lead is located in the thickness direction at the joint between the lead and the current collecting bundle portion. The groove does not protrude toward the side where the current collecting bundle portion protrudes in the length direction relative to the lead. Each of the one or more recesses is further recessed from the groove bottom of the groove toward the side where the lead is located. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a battery according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of the configuration of the electrode group in the battery according to the first embodiment, taken along a cross section perpendicular or substantially perpendicular to the width direction of the electrode group. [Figure 3] FIG. 3 is a schematic diagram showing an example of the joint (connection) portion of one current collecting bundle portion of an electrode group to a lead and the configuration of the surrounding area in a battery according to the first embodiment, viewed from one side in the thickness direction of the electrode group. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a cross section taken along the imaginary line A1 in FIG. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a cross section taken along the imaginary line A2 in FIG. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of a joining device used in manufacturing a battery in the first embodiment. [Figure 7] FIG. 7 is a perspective view schematically showing an example of the configuration of a joining tip portion of the joining jig according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view schematically illustrating an example of a state in which one current collecting bundle portion of the electrode group is joined to a lead in a cross section perpendicular or substantially perpendicular to the width direction of the electrode group in the first embodiment. [Figure 9]FIG. 9 is a cross-sectional view schematically illustrating an example of a state in which one current collecting bundle portion of an electrode group is joined to a lead in a cross section perpendicular or substantially perpendicular to the longitudinal direction of the electrode group in the first embodiment. [Figure 10] FIG. 10 is a schematic diagram showing an example of the joint (connection) portion of one current collecting bundle portion of an electrode group to a lead and the configuration of the surrounding area in a battery according to the first modified example, viewed from one side in the thickness direction of the electrode group. [Figure 11] FIG. 11 is a schematic diagram showing an example of the joint (connection) portion of one current collecting bundle portion of an electrode group to a lead and the configuration of the surrounding area in a battery according to the second modified example, viewed from one side in the thickness direction of the electrode group. [Figure 12] FIG. 12 is a schematic diagram showing an example of the joint (connection) portion of one current collecting bundle portion of an electrode group to a lead and the configuration of the surrounding area in a battery according to the third modified example, viewed from one side in the thickness direction of the electrode group. [Figure 13] FIG. 13 is a cross-sectional view schematically showing a cross section taken along the imaginary line A3 in FIG. [Figure 14] FIG. 14 is a perspective view schematically showing an example of the configuration of a joining tip portion of a joining jig according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings.

[0011] (First embodiment) FIG. 1 schematically illustrates an example of the configuration of a battery 1 according to the first embodiment. The battery 1 of FIG. 1 includes an electrode group 2 and an exterior part 3. The exterior part 3 includes an exterior container 5 and a lid member 6. The battery 1 and the exterior part 3 are defined as having a depth direction (a direction perpendicular or substantially perpendicular to the plane of FIG. 1 ), a lateral direction (direction indicated by arrow Y) that intersects (orthogonal or substantially perpendicular to) the depth direction, and a height direction (direction indicated by arrow Z) that intersects (orthogonal or substantially perpendicular to) both the depth and lateral directions. The dimensions of the battery 1 and the exterior part 3 along the depth direction are smaller than the dimensions along the lateral direction and the height direction, respectively. Note that FIG. 1 illustrates a cross section perpendicular or substantially perpendicular to the depth direction.

[0012] The outer container 5 has a bottom wall 7 and a peripheral wall 8. Inside the outer container 5, 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 to the side on which the bottom wall 7 is located in the height direction. The lid member 6 is attached to the peripheral wall 8 at an end opposite to 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 with the internal cavity 10 sandwiched between them.

[0013] The electrode group 2 includes a positive electrode and a negative electrode. In the electrode group 2, a separator is interposed between the positive electrode and the negative electrode. In the electrode group 2, the separator is formed of an electrically insulating material and electrically insulates the positive electrode from the negative electrode. In the electrode group 2, the positive electrode includes a positive electrode current collector such as a positive electrode current collector foil, and a positive electrode active material-containing layer coated (supported) on the surface of the positive electrode current collector. The positive electrode current collector includes an uncoated portion 11 where the positive electrode active material-containing layer is uncoated (unsupported). In the electrode group 2, the negative electrode includes a negative electrode current collector such as a negative electrode current collector foil, and a negative electrode active material-containing layer coated (supported) on the surface of the negative electrode current collector. The negative electrode current collector includes an uncoated portion 11 where the negative electrode active material-containing layer is uncoated (unsupported). Due to the configuration as described above, in the electrode group 2, the uncoated portion 11 of the positive electrode and the uncoated portion 11 of the negative electrode are formed as a pair of uncoated portions 11. The uncoated portion 11 of the positive electrode is also referred to as the "positive electrode uncoated portion," and the uncoated portion 11 of the negative electrode is also referred to as the "negative electrode uncoated portion."

[0014] FIG. 2 schematically illustrates an example of the configuration of the electrode group 2 in the battery 1 according to the first embodiment. As illustrated in FIGS. 1 and 2, the electrode group 2 has a length direction (the direction indicated by arrows L1 and L2), a width direction (the direction indicated by arrow W) that intersects (is perpendicular or substantially perpendicular to) the length direction, and a thickness direction (the direction indicated by arrows C1 and C2) that intersects (is perpendicular or substantially perpendicular to) both the length direction and the width direction. The dimension of the electrode group 2 along the thickness direction is smaller than the dimension along the length direction and the dimension along the width direction. Note that FIG. 1 illustrates the electrode group 2 as viewed from one side in the thickness direction, and FIG. 2 illustrates the electrode group 2 in a cross section perpendicular or substantially perpendicular to the width direction.

[0015] In one example, the electrode group 2 is formed in a so-called wound structure, in which the positive electrode, the negative electrode, and the separator are wound around a winding axis with a separator interposed between the positive electrode and the negative electrode. In this case, the winding axis of the wound structure of the electrode group 2 is along the length direction of the electrode group 2. In another example, the electrode group 2 is formed in a so-called stack structure, in which multiple positive electrode plates and multiple negative electrode plates are alternately stacked in the thickness direction of the electrode group 2. In this case, in the electrode group 2, multiple positive electrode plates constitute a positive electrode, and multiple negative electrode plates constitute a negative electrode. Then, multiple positive electrode plates and multiple negative electrode plates are stacked with a separator interposed between the positive electrode plate and the negative electrode plate adjacent in the thickness direction (stacking direction).

[0016] In the internal cavity 10, the electrode group 2 is retained (impregnated) with an electrolyte solution (not shown). The electrolyte solution may be an aqueous electrolyte solution such as an aqueous solution, or a nonaqueous electrolyte solution in which an electrolyte is dissolved in an organic solvent. Alternatively, a gel electrolyte or a solid electrolyte may be used instead of the electrolyte solution. When a solid electrolyte is used as the electrolyte, the separator in the electrode group 2 may be formed from the solid electrolyte. A gas release valve and a liquid inlet may be formed in the lid member 6 of the exterior part 3. In this case, a sealing plate that closes the liquid inlet is welded to the outer surface of the lid member 6. The gas release valve, the liquid inlet, etc. may not be provided in the battery 1.

[0017] In the example shown in FIGS. 1 and 2 , in the electrode group 2, the positive electrode uncoated portion (positive electrode uncoated portion 11) protrudes to one side in the longitudinal direction of the electrode group 2. In the electrode group 2, the negative electrode uncoated portion (negative electrode uncoated portion 11) protrudes to the side opposite the side in the longitudinal direction from which the positive electrode uncoated portion protrudes. A current collecting bundle portion 12 is formed in each of the pair of uncoated portions 11. In the example shown in FIGS. 1 and 2 , one current collecting bundle portion 12 is formed in each of the positive electrode uncoated portion and the negative electrode uncoated portion. Each current collecting bundle portion 12 includes a plurality of current collecting band portions 13. In each current collecting bundle portion 12, the multiple current collecting band portions 13 are bundled in a stacked state in the thickness direction of the electrode group 2. Therefore, the stacking direction of the current collecting band portions 13 in each current collecting bundle portion 12 coincides or approximately coincides with the thickness direction of the electrode group 2.

[0018] In the current collecting bundle part 12 of the uncoated positive electrode portion, each of the multiple current collecting band parts 13 bundled together is formed from a positive electrode current collector. In the current collecting bundle part 12 of the uncoated negative electrode portion, each of the multiple current collecting band parts 13 bundled together is formed from a negative electrode current collector. In the electrode group 2, the current collecting bundle part 12 of the uncoated positive electrode portion protrudes to one side in the longitudinal direction, and the current collecting bundle part 12 of the uncoated negative electrode portion protrudes to the side opposite to the side from which the uncoated positive electrode portion protrudes in the longitudinal direction.

[0019] In the example battery 1 of FIG. 1 , the electrode group 2 is housed in the internal cavity 10 with the thickness direction of the electrode group 2 aligned along the depth direction of the battery 1 and the length direction of the electrode group 2 aligned along the lateral direction of the battery 1. The electrode group 2 is disposed in the internal cavity 10 with the width direction of the electrode group 2 aligned along the height direction of the battery 1. Because the electrode group 2 is disposed in the internal cavity 10 in this manner, in the example battery 1 of FIG. 1 , the current collecting bundle portion 12 of the uncoated portion of the positive electrode protrudes to one side in the lateral direction, and the current collecting bundle portion 12 of the uncoated portion of the negative electrode protrudes to the side opposite the side from which the uncoated portion of the positive electrode protrudes.

[0020] In the example battery 1 shown in FIG. 1 , a pair of terminals 15 are attached to the lid member 6. Each of the pair of terminals 15 is exposed to the outside of the battery 1 and is disposed on the outer surface of the lid member 6. The terminals 15 are formed from a conductive material such as metal. One of the pair of terminals 15 serves as a positive terminal of the battery 1, and the other of the pair of terminals 15 serves as a negative terminal of the battery 1. In the example shown in FIG. 1 , an insulating member 16 is disposed on the outer surface of the lid member 6, between each of the pair of terminals 15 and the lid member 6. Each of the pair of terminals 15 is electrically insulated by the insulating member 16 from the exterior part 3, which includes the outer container 5 and the lid member 6.

[0021] In the example shown in FIG. 1 , a pair of leads 17 are housed in the internal cavity 10 of the exterior part 3. Each of the leads 17 is made of a conductive material and is conductive. One of the pair of leads 17 serves as a positive electrode lead, and the other of the pair of leads 17 serves as a negative electrode lead. In the battery 1, the positive electrode terminal is connected to the positive electrode lead, and the negative electrode terminal is connected to the negative electrode lead. In the battery 1, the current collecting bundle part 12 of the uncoated positive electrode part is joined (connected) to the positive electrode lead and is electrically connected to the positive electrode terminal via the positive electrode lead. The current collecting bundle part 12 of the uncoated negative electrode part is joined (connected) to the negative electrode lead and is electrically connected to the negative electrode terminal via the negative electrode lead. Therefore, in each of the pair of uncoated parts 11, the current collecting bundle part 12 is joined (connected) to the corresponding one of the pair of leads 17.

[0022] 1 and 2, a clip (backup lead) 18 is attached to the current collecting bundle portion 12 in each of the pair of uncoated portions 11. Each of the clips 18 is formed from a conductive material. In each of the uncoated portions 11, the current collecting bundle portion 12 is joined (connected) to a corresponding one of the pair of leads 17 via the clip 18. In the internal cavity 10 of the outer container 5, the pair of uncoated portions 11, the pair of leads 17, and the clip 18 are electrically insulated from the outer container 5 and the outer package 3 including the lid member 6 by one or more insulating members (not shown).

[0023] In the example battery 1 shown in FIG. 1 , each of a pair of leads 17 includes a top plate portion 21 and a leg plate portion 22, and each lead 17 is formed with one leg plate portion 22. In the internal cavity 10, the top plate portion 21 of each lead 17 is disposed between the lid member 6 and the electrode group 2 in the height direction of the battery 1. In each lead 17, the leg plate portion 22 is connected to the top plate portion 21. In the internal cavity 10, the leg plate portion 22 of each lead 17 extends along the height direction of the battery 1 from the connection position to the top plate portion 21 toward the side where the bottom wall 7 is located.

[0024] In the battery 1, the leg plate portion 22 of the positive electrode lead is joined to the current collecting bundle portion 12 and the clip 18 in a state where it is stacked on the current collecting bundle portion 12 of the uncoated portion of the positive electrode from one side in the thickness direction of the electrode group 2 (depth direction of the battery 1). In the battery 1, the leg plate portion 22 of the negative electrode lead is joined to the current collecting bundle portion 12 and the clip 18 in a state where it is stacked on the current collecting bundle portion 12 of the uncoated portion of the negative electrode from one side in the thickness direction of the electrode group 2. Therefore, in each of the pair of leads 17, the leg plate portion 22 serves as a joining plate portion that is joined to a corresponding one of the current collecting bundle portions 12. In each of the leads 17, the leg plate portion 22 that serves as the joining plate portion is joined (connected) to a corresponding one of the current collecting bundle portions 12 in a state where it is stacked on top of a corresponding one of the current collecting bundle portions 12 from one side in the thickness direction of the electrode group 2.

[0025] 3 to 5 schematically show an example of the structure of a joint (connection) between a current collecting bundle portion 12 of an electrode group 2 and a lead 17, and the surrounding area, in a battery 1 according to the first embodiment. FIG. 3 shows a view from one side in the thickness direction of the electrode group 2 (the depth direction of the battery 1 and the stacking direction of the multiple current collecting bundle portions 13), and also shows a view from the opposite side to the side where the leads 17 (leg plate portions 22) in the thickness direction of the electrode group 2 are stacked. FIG. 4 shows a cross-sectional view taken along imaginary line A1 in FIG. 3, which is orthogonal or approximately orthogonal to the width direction of the electrode group 2 (the height direction of the battery 1). FIG. 5 shows a cross-sectional view taken along imaginary line A2 in FIG. 3, which is orthogonal or approximately orthogonal to the length direction of the electrode group 2 (the protruding direction of the current collecting bundle portions 12 and the lateral direction of the battery 1).

[0026] The following describes the configuration of the joint (connection) portion of one current collecting bundle part 12 to the lead 17. In the battery 1, the configuration of the joint portion of the current collecting bundle part 12 to the lead 17 in each of the positive electrode uncoated part and the negative electrode uncoated part is the same as the configuration described below.

[0027] As shown in FIGS. 3 to 5 , the clip 18 clamps the current collecting bundle portion 12 from both sides in the thickness direction of the electrode group 2 (the stacking direction of the multiple current collecting bundle portions 13) at and near the joint (connection) where the current collecting bundle portion 12, lead 17, and clip 18 are joined. The clip 18 is attached to the current collecting bundle portion 12 from the side from which the current collecting bundle portion 12 protrudes (the outer side in the longitudinal direction of the electrode group 2) so as to be close to the protruding end E1 of the current collecting bundle portion 12. In a cross section perpendicular or substantially perpendicular to the width direction of the electrode group 2, the clip 18 has a U-shape or a substantially U-shape (see FIGS. 2 and 4 ). The U-shape or substantially U-shape of the clip 18 opens inward in the longitudinal direction of the electrode group 2, i.e., toward the opposite side from the side from which the current collecting bundle portion 12 protrudes (the side indicated by the arrow L2 in FIGS. 3 and 4 ).

[0028] 3 to 5, etc., the leg plate portion 22 of the lead 17 is stacked on the current collecting bundle portion 12 and the clip 18 from one side in the thickness direction of the electrode group 2 (the side indicated by arrow C1 in FIGS. 4 and 5). Then, the leg plate portion 22 of the lead 17 is joined (connected) to the current collecting bundle portion 12 and the clip 18 in a state where it is stacked on the current collecting bundle portion 12 and the clip 18. At the joint portion and its vicinity, the lead 17 abuts against the clip 18 from one side in the thickness direction of the electrode group 2. Furthermore, the leg plate portion 22 is joined to the current collecting bundle portion 12 in a state where its plate width direction is along the length direction of the electrode group 2 (the protruding direction of the current collecting bundle portion 12) and its plate thickness direction is along the thickness direction of the electrode group 2 (the stacking direction of the multiple current collecting band portions 13).

[0029] A groove 23 is formed at the joint between the lead 17 and the current collecting bundle part 12. The groove 23 includes a groove circumferential surface 25 and a groove bottom (groove bottom surface) 26. The groove 23 is recessed toward the lead 17 up to the groove bottom 26, and is recessed toward the side where the lead 17 is located in the thickness direction of the electrode group 2 (the side indicated by arrow C1). The groove 23 opens toward the side opposite the side where the lead 17 is located in the thickness direction of the electrode group 2. The edge of the opening of the groove 23 is formed by the groove circumferential surface 25. A reference surface 27 is formed on the outer surface of the clip 18, facing away from the side where the leads 17 are stacked in the thickness direction of the electrode group 2. In the example shown in FIGS. 3 to 5 , the groove 23 opens at the reference surface 27 of the clip 18. The groove 23 is recessed from the reference surface 27 toward the side where the leads 17 are located, and a step is formed between the reference surface 27 and the groove bottom 26 by the groove peripheral surface 25 .

[0030] Furthermore, the leg plate portion (joining plate portion) 22 of the lead 17 has a pair of plate edges 31, 32 that form both edges in the plate width direction. In the leg plate portion 22, the plate edge (first plate edge) 31 forms the edge on one side in the plate width direction, and the plate edge (second plate edge) 32 forms the edge on the opposite side in the plate width direction from the plate edge 31. In the leg plate portion 22 joined to the current collecting bundle portion 12, the plate edge 31 is located closer to the protruding end E1 of the current collecting bundle portion 12 than the plate edge 32. In other words, at the joint portion and its vicinity, the plate edge 31 is located on the side where the current collecting bundle portion 12 protrudes (the side of the arrow L1 in Figures 3 and 4) relative to the plate edge 32.

[0031] In the joint portion of this embodiment, the entire groove portion 23 including the groove bottom portion 26 is located on the opposite side (inner side in the longitudinal direction of the electrode group 2) from the side from which the current collecting bundle portion 12 protrudes with respect to the plate edge 31 of the leg plate portion 22. Therefore, in the joint portion, the groove portion 23 (groove circumferential surface portion 25 and groove bottom portion 26) does not protrude (does not protrude) from the lead 17 toward the side from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2.

[0032] In a preferred example of this embodiment, at the joint portion, the entire groove portion 23 is located on the side where the current collecting bundle portion 12 protrudes (outside in the longitudinal direction of the electrode group 2) with respect to the plate edge 32 of the leg plate portion 22. In this case, at the joint portion, the groove portion 23 does not protrude (does not protrude) on the side opposite the side where the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2 with respect to the lead 17. Therefore, at the joint portion, the entire groove portion 23 is contained within the range between the plate edges 31, 32 of the leg plate portion 22 in the longitudinal direction of the electrode group 2.

[0033] Furthermore, in this embodiment, one or more recesses 33 are formed in the joint portion. Each of the recesses 33 is recessed further from the groove bottom 26 of the groove 23 toward the side where the lead 17 is located in the thickness direction of the electrode group 2. Due to this configuration, the recess depth of each of the recesses 33 formed in the joint portion is greater than the recess depth up to the groove bottom 26 of the groove 23.

[0034] In one example, each of the recesses 33 does not reach the lead 17, and the bottom of each of the recesses 33 is located at a position close to the reference plane 27 relative to the lead 17. In another example, each of the recesses 33 is recessed from the groove bottom 26 to the lead 17. Each of the recesses 33 is formed in, for example, any of a polygonal pyramid shape, a polygonal truncated pyramid shape, a cone shape, a cone truncated cone shape, and shapes similar thereto. At the joining portion, one or more recesses 33 form a recessed structure portion 30 recessed from the groove bottom 26.

[0035] In the example shown in FIGS. 3 to 5 , the recessed structure 30 is composed of a plurality of (three) recesses 33. The recesses 33 are aligned along the width direction of the electrode group 2, and the recesses 33 form one recessed portion row 35. In the example shown in FIGS. 3 to 5 (recessed portion row 35), the recesses 33 are not shifted or are barely shifted relative to one another in the longitudinal direction of the electrode group 2. Therefore, the distances from the protruding end E1 of the current collecting bundle portion 12 along the longitudinal direction of the electrode group 2 are the same or approximately the same for the recesses 33 that form the recessed portion row 35. In the example shown in FIGS. 3 to 5 , only one recessed portion row 35 is formed in the recessed structure 30. Therefore, the distances from the protruding end E1 of the current collecting bundle portion 12 along the longitudinal direction of the electrode group 2 are the same or approximately the same for the recesses 33 that form the recessed structure 30.

[0036] In a preferred example, the groove 23 (groove bottom 26) does not protrude toward the side from which the current collecting bundle portion 12 protrudes (outside in the longitudinal direction of the electrode group 2) relative to any of the recesses 33 forming the recess row 35. In this case, the groove bottom 26 is not adjacent to any of the recesses 33 from the side from which the current collecting bundle portion 12 protrudes. The groove 23 does not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to the recess row 35, and does not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to the recess structure 30 composed of the multiple recesses 33. In the recess structure 30, for example, the position through which the imaginary line α1 (see FIG. 3) passes is the end on the side from which the current collecting bundle portion 12 protrudes.

[0037] In a more preferred example, the grooves 23 do not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to any of the recesses 33 forming the recess row 35, and do not protrude toward the opposite side from the side from which the current collecting bundle portion 12 protrudes (inward in the longitudinal direction of the electrode group 2). In this case, the groove bottoms 26 are not adjacent to the recesses 33 from either the side from which the current collecting bundle portion 12 protrudes or the side opposite to the side from which the current collecting bundle portion 12 protrudes. The grooves 23 do not protrude toward either the side from which the current collecting bundle portion 12 protrudes relative to the recess row 35 or the side opposite to the side from which the current collecting bundle portion 12 protrudes, and do not protrude toward either one side or the other side in the longitudinal direction of the electrode group 2 relative to the recessed structure 30 formed by the multiple recesses 33. Note that, in the recessed structure 30, for example, the position through which the imaginary line α2 (see FIG. 3) passes is the end opposite to the side from which the current collecting bundle portion 12 protrudes.

[0038] 3 to 5, in the recess row 35, each of the multiple recesses 33 has a gap between adjacent recesses 33. At the joint portion, the groove bottom 26 of the groove 23 extends between adjacent recesses 33 in the recess row 35 in the width direction of the electrode group 2. Therefore, in the example of FIGS. 3 to 5, the multiple recesses 33 constituting the recessed structure 30 include two recesses 33 spaced apart in the width direction of the electrode group 2. The groove bottom 26 of the groove 23 extends between the two recesses 33 spaced apart in the width direction.

[0039] 3 to 5, in the joint portion, the groove bottoms 26 of the grooves 23 are adjacent to the recessed portion rows 35 from the outside in the width direction of the electrode group 2, and are adjacent to the recessed portion rows 35 from both sides in the width direction of the electrode group 2. Therefore, in the example of FIGS. 3 to 5, the groove bottoms 26 of the grooves 23 are adjacent to the recessed structure portion 30 composed of a plurality of recesses 33 from the outside in the width direction of the electrode group 2. In the example of FIGS. 3 to 5, the groove bottoms 26 are adjacent to each of the plurality of recesses 33 from both sides in the width direction of the electrode group 2. In the portion where the recessed portion rows 35 are formed, the groove bottoms 26 and the recessed portions 33 are alternately arranged along the width direction of the electrode group 2 (the arrangement direction of the recessed portion rows 35).

[0040] 3 to 5, the groove bottom 26 of the groove 23 extends between two recesses 33 spaced apart in the width direction of the electrode group 2, and is adjacent to the recessed structure 30 composed of multiple recesses 33 from the outside in the width direction of the electrode group 2. Due to this configuration, the groove bottom 26 is adjacent to at least one of the recesses 33 constituting the recessed structure 30 in the width direction of the electrode group 2.

[0041] In manufacturing the battery 1 configured as described above, after forming the electrode group 2, the current collecting bundle part 12 is joined to a corresponding one of a pair of leads 17 in each of a pair of uncoated portions 11 of the electrode group 2 by ultrasonic welding or the like. At this time, in each of the uncoated portions 11, the lead 17 is stacked on the current collecting bundle part 12 from one side in the thickness direction of the electrode group 2. Then, by joining the joining target parts where the current collecting bundle part 12 and the lead 17 are stacked, the current collecting bundle part 12 is joined to the lead 17 in each of the uncoated portions 11. Then, each of the pair of uncoated portions 11 is electrically connected to a corresponding one of the pair of terminals 15 via a corresponding one of the leads 17.

[0042] In one example, with a corresponding one of a pair of terminals 15 connected to each of the pair of leads 17, each of the pair of uncoated portions 11 is joined to a corresponding one of the pair of leads 17. In another example, after each of the pair of uncoated portions 11 is joined to a corresponding one of the pair of leads 17, each of the pair of terminals 15 is connected to the corresponding one of the pair of leads 17.

[0043] In manufacturing the example battery 1 of FIG. 1 , the electrode group 2, the pair of leads 17, etc. are housed in the internal cavity 10 of the outer container 5, with each of the pair of uncoated portions 11 electrically connected to a corresponding one of the pair of terminals 15 via a corresponding one of the pair of leads 17. Then, with the electrode group 2 and the leads 17 housed in the internal cavity 10, a lid member 6 is attached to the peripheral wall 8 of the outer container 5, and the opening of the internal cavity 10 is closed with the lid member 6. Then, a predetermined process, including injection of an electrolyte solution into the internal cavity 10, is performed, thereby manufacturing the battery 1. The current collecting bundle portion 12 is joined to the leads 17 using a joining device.

[0044] 6 schematically shows an example of the configuration of a bonding device 40 used in manufacturing the battery 1 in the first embodiment. In this embodiment, for example, the bonding device 40 is used to bond each of the current collecting bundle portions 12 of the electrode group 2 to a corresponding one of the leads 17. As shown in FIG. 6 and other figures, the bonding device 40 includes a bonding jig 41, a stage 42 such as an anvil, a pressure unit 45, and an ultrasonic vibrator 43. When bonding parts to be bonded using the bonding device 40, the parts to be bonded are sandwiched between the bonding jig 41 and the stage 42.

[0045] The pressure applying unit 45 applies pressure to the joining jig 41 while the parts to be joined are sandwiched between the joining jig 41 and the stage 42. As a result, the parts to be joined sandwiched between the joining jig 41 and the stage 42 are pressed by the joining jig 41. Note that in one example, the pressure applying unit 45 applies pressure to the stage 42 instead of the joining jig 41. In this case, the parts to be joined sandwiched between the joining jig 41 and the stage 42 are pressed by the stage 42. In another example, the pressure applying unit 45 applies pressure to both the joining jig 41 and the stage 42. In this case, the parts to be joined sandwiched between the joining jig 41 and the stage 42 are pressed by both the joining jig 41 and the stage 42.

[0046] The ultrasonic vibrator 43 generates ultrasonic vibrations when supplied with AC power such as high-frequency power. Then, with the parts to be joined sandwiched between the joining jig 41 and the stage 42, the ultrasonic vibrator 43 transmits the generated ultrasonic vibrations to the parts to be joined through the joining jig 41. Therefore, with the parts to be joined sandwiched between the joining jig 41 and the stage 42, the joining device 40 applies pressure to at least one of the joining jig 41 and the stage 42 and transmits ultrasonic vibrations to the parts to be joined, thereby joining the parts to be joined by ultrasonic welding or the like.

[0047] The joining jig 41 includes a jig body 46 and a joining tip portion 47. In the joining jig 41, the jig body 46 extends from the base end side to the tip end side, and the joining tip portion 47 is connected to the tip end of the jig body 46. In the example shown in Fig. 6, the joining tip portion 47 is bent with respect to the jig body 46. However, in another example, the joining tip portion 47 may not be bent with respect to the jig body 46, but may extend straight or approximately straight with respect to the jig body 46.

[0048] When joining the parts to be joined, the joining tip 47 is brought into contact with the parts to be joined, and the parts to be joined are sandwiched between the joining tip 47 and the stage 42. In addition, in a configuration in which pressure is applied to the joining jig 41 from the pressure unit 45, the joining tip 47 presses the parts to be joined due to the pressure applied from the pressure unit 45. In addition, vibrations generated by the ultrasonic vibrator 43 are transmitted to the parts to be joined through the jig body 46 and the joining tip 47 in this order.

[0049] When joining the current collecting bundle part 12 to the lead 17, an overall thickness T1 and a thickness T2 of the part excluding the lead 17 are defined for the part to be joined, in which the lead 17 is stacked on the current collecting bundle part 12 (see FIG. 6). Here, the thickness T1 corresponds to the overall dimension (total thickness) of the part to be joined along the thickness direction of the electrode group 2, and the thickness T2 corresponds to the dimension of the part to be joined along the thickness direction of the electrode group 2 excluding the lead 17. When forming the example battery 1 of FIG. 1, the thickness T2 corresponds to the thickness of the part to be joined formed by the current collecting bundle part 12 and the clip 18.

[0050] FIG. 7 is a perspective view schematically illustrating an example of the configuration of the joining tip 47 of the joining jig 41 according to the first embodiment. As illustrated in FIG. 7 and other figures, the joining tip 47 includes a base 51 and a protruding base 52 protruding from the base 51. The joining tip 47 of the joining jig 41 defines the protruding direction of the protruding base 52 (the direction indicated by arrow P). In the example illustrated in FIG. 7, a base surface 55 is formed on the base 51, and the protruding base 52 protrudes from the base surface 55 in the protruding direction. The joining tip 47 also defines the width direction (the direction indicated by arrow H) of the protruding base 52, which intersects (is perpendicular or substantially perpendicular to) the protruding direction of the protruding base 52, and the depth direction (the directions indicated by arrows D1 and D2), which intersects (is perpendicular or substantially perpendicular to) both the protruding direction and the width direction.

[0051] The protruding base portion 52 includes a base portion (base surface) 56 and a pair of base side portions (base side surfaces) 57, 58. The base portion 56 faces the protruding direction, and the protruding end (protruding end surface) of the protruding portion of the protruding base portion 52 from the base surface 55 of the base portion 51 is formed by the base portion 56. Each of the base side portions 57, 58 extends from the base portion 51 to the base portion 56 in the protruding direction of the protruding base portion 52 and forms part of the outer peripheral surface of the protruding base portion 52. Each of the base side portions 57, 58 extends from the base of the protrusion of the protruding base portion 52 to the protruding end. The outer peripheral surface of the protruding base portion 52 extends from the base surface 55 to the base portion 56 along the protruding direction of the protruding base portion 52.

[0052] The base side portion (first base side portion) 57 faces one side in the depth direction of the protruding base portion 52 (the side indicated by the arrow D1), and one end of the protruding base portion 52 in the depth direction is formed by the base side portion 57. The base side portion (second base side portion) 58 faces the side opposite to the side of the protruding base portion 52 in the depth direction that the base side portion 57 faces (the side indicated by the arrow D2), and the end of the protruding base portion 52 opposite to the base side portion 57 in the depth direction is formed by the base side portion 58.

[0053] In this embodiment, one or more protrusions 53 are provided on the joining tip 47. Each of the protrusions 53 further protrudes from the pedestal 56 in the protruding direction of the protruding base 52. Therefore, each of the protrusions 53 further protrudes from the protruding end of the protruding base 52. Here, a protrusion length X1 of the protruding base 52 along the protruding direction from the base 51 (base surface) 55 to the pedestal 56 and a protrusion length X2 along the protruding direction from the base 51 (base surface) 55 to the protruding end of one or more protrusions 53 are respectively defined (see FIG. 9 described later). In the joining tip 47, the protrusion length X2 is longer than the protrusion length X1. Each of the protrusions 53 is formed in, for example, a polygonal pyramid shape, a polygonal truncated pyramid shape, a cone shape, a cone truncated cone shape, or any similar shape. In the joining tip 47, one or more protrusions 53 form a convex structure 50 protruding from the pedestal 56.

[0054] Each of the one or more protrusions 53 has a pair of protrusion side portions (protrusion side surfaces) 61, 62. In each of the one or more protrusions 53, each of the protrusion side portions 61, 62 extends from the base portion 56 of the protrusion base portion 52 in the protrusion direction, extending from the protrusion base to the protrusion end of the protrusion 53. In addition, in each of the one or more protrusions 53, each of the protrusion side portions 61, 62 forms a part of the outer peripheral surface of the protrusion 53. In addition, in each of the protrusions 53, the outer peripheral surface extends along the protrusion direction of the protrusion base portion 52 from the base portion 56 to the protrusion end of the protrusion 53.

[0055] In each of the protrusions 53, the protrusion side portion (first protrusion side portion) 61 faces the side (arrow D1 side) in the depth direction that the platform side portion (first platform side portion) 57 faces, and the protrusion side portion (second protrusion side portion) 62 faces the side (arrow D2 side) in the depth direction that the platform side portion (second platform side portion) 58 faces. In each of the protrusions 53, one end in the depth direction is formed by the protrusion side portion 61, and the end opposite to the protrusion side portion 61 in the depth direction is formed by the protrusion side portion 62.

[0056] In the example of FIG. 7 , the convex structure 50 is composed of multiple (three) protrusions 53. The multiple protrusions 53 are aligned along the width direction of the protruding base 52, and a single protrusion row 63 is formed by the multiple protrusions 53. In the example of the convex structure 50 (protrusion row 63) of FIG. 7 , the multiple protrusions 53 are not misaligned or are barely misaligned with each other in the depth direction of the protruding base 52. Therefore, the distances from the base side portions 57 along the depth direction of the protruding base 52 are the same or approximately the same for the multiple protrusions 53 that form the protrusion row 63. The distances from the base side portions 58 along the depth direction of the protruding base 52 are the same or approximately the same for the multiple protrusions 53 that form the protrusion row 63.

[0057] 7, only one projection row 63 is formed in the convex structure 50. Therefore, the distances from the base side portions 57 along the depth direction of the protruding base portions 52 are the same or approximately the same for the multiple projections 53 that make up the convex structure 50. The distances from the base side portions 58 along the depth direction of the protruding base portions 52 are the same or approximately the same for the multiple projections 53 that make up the convex structure 50.

[0058] In one example of this embodiment, the base portion 56 does not protrude toward the side where the base side portion (first base side portion) 57 faces relative to any of the protrusions 53 forming the protrusion row 63. In this case, the protrusion side portion 61 of each protrusion 53 is connected to the base side portion 57 of the protruding base portion 52 without the base portion 56 therebetween. The base portion 56 does not protrude toward the side where the base side portion 57 faces relative to the protrusion row 63, and does not protrude toward the side where the base side portion 57 faces relative to the convex structure portion 50 formed by the multiple protrusions 53. Note that in the convex structure portion 50, for example, the position where the virtual line β1 (see FIG. 7) passes through is the end on the side where the base side portion 57 faces.

[0059] In a preferred example, the base portion 56 does not protrude toward the side toward which the base side portion 57 faces, relative to any of the protrusions 53 forming the protrusion row 63, and does not protrude toward the side toward which the base side portion (second base side portion) 58 faces. In this case, in each of the protrusions 53, the protrusion side portion 61 is connected to the base side portion 57 of the protruding base portion 52 without the base portion 56 therebetween, and the protrusion side portion 62 is connected to the base side portion 58 of the protruding base portion 52 without the base portion 56 therebetween. The base portion 56 does not protrude toward either the side toward which the base side portion 57 faces or the side toward which the base side portion 58 faces, relative to the protrusion row 63, and does not protrude toward either one side or the other side in the depth direction of the protruding base portion 52, relative to the convex structure portion 50 formed by the multiple protrusions 53. In the convex structure portion 50, for example, the position where the imaginary line β2 (see FIG. 7) passes through is the end on the side where the platform side portion 58 faces.

[0060] 7, in the protrusion row 63, each of the multiple protrusions 53 has a gap between adjacent protrusions 53. In the joining tip portion 47, a pedestal portion 56 extends between adjacent protrusions 53 in the protrusion row 63 in the width direction of the protruding base portion 52. Therefore, in the example of FIG. 7, the multiple protrusions 53 constituting the convex structure portion 50 include two protrusions 53 that are spaced apart in the width direction of the protruding base portion 52. The pedestal portion 56 extends between the two protrusions 53 that are spaced apart in the width direction.

[0061] 7, in the joining tip portion 47, the pedestal portion 56 is adjacent to the protrusion row 63 from the outside in the width direction of the protruding base portion 52, and is adjacent to the protrusion row 63 from both sides in the width direction of the protruding base portion 52. Therefore, in the example of FIG. 7, the pedestal portion 56 is adjacent to the convex structure portion 50 composed of the multiple protrusions 53 from the outside in the width direction of the protruding base portion 52. In the example of FIG. 7, the pedestal portion 56 is adjacent to each of the multiple protrusions 53 from both sides in the width direction of the protruding base portion 52. In the portion where the protrusion row 63 is formed, the pedestal portions 56 and the protrusions 53 are arranged alternately along the width direction of the protruding base portion 52 (the arrangement direction of the protrusion row 63).

[0062] 7, the base portion 56 extends between two protrusions 53 spaced apart in the width direction of the protruding base portion 52, and is adjacent to the protruding structure portion 50 made up of the multiple protrusions 53 from the outside in the width direction of the protruding base portion 52. Due to this configuration, the base portion 56 is adjacent to at least one of the protrusions 53 constituting the protruding structure portion 50 in the width direction of the protruding base portion 52.

[0063] When joining the current collecting bundle part 12 to the leads 17, the joining target part, in which the current collecting bundle part 12 and the leads 17 are stacked, is sandwiched between the joining tip part 47 of the joining jig 41 and the stage 42. At this time, as shown in Fig. 6 and other figures, the joining tip part 47 comes into contact with the joining target part from the side opposite to the side on which the leads 17 are stacked in the thickness direction of the electrode group 2. Then, the stage 42 comes into contact with the joining target part from the side on which the leads 17 are stacked in the thickness direction of the electrode group 2.

[0064] Then, with the parts to be joined sandwiched between the joining jig 41 and the stage 42, pressure is applied to at least one of the joining jig 41 and the stage 42 by the pressure unit 45, and the parts to be joined are pressed by at least one of the joining jig 41 and the stage 42. Also, with the parts to be joined sandwiched between the joining jig 41 and the stage 42, ultrasonic vibrations are transmitted to the parts to be joined through the joining jig 41. Thereby, the parts to be joined are joined, and a bonded part is formed where the current collecting bundle part 12 and the lead 17 are joined.

[0065] 8 and 9 schematically show an example of a state in which one current collecting bundle portion 12 of the electrode group 2 is joined to a lead 17 in the first embodiment. FIG. 8 shows a cross section perpendicular or substantially perpendicular to the width direction of the electrode group 2, and FIG. 9 shows a cross section perpendicular or substantially perpendicular to the length direction of the electrode group 2 (the protruding direction of the current collecting bundle portion 12). Also, FIG. 8 shows a part of the joining tip portion 47 in a cross section perpendicular or substantially perpendicular to the width direction of the protruding base portion 52, and the remaining part when viewed from one side in the width direction of the protruding base portion 52. Also, FIG. 9 shows a part of the joining tip portion 47 in a cross section perpendicular or substantially perpendicular to the depth direction of the protruding base portion 52, and the remaining part when viewed from one side in the depth direction of the protruding base portion 52. Also, FIG. 9 shows the protruding length X1 of the protruding base portion 52 from the base portion 51 and the protruding length X2 of one or more protrusions 53 from the base portion 51 for the joining tip portion 47.

[0066] The following describes the joining of one current collecting bundle part 12 to the lead 17. In the manufacture of the battery 1, the joining of the current collecting bundle part 12 to the lead 17 in each of the positive electrode uncoated part and the negative electrode uncoated part is performed in the same manner as described below.

[0067] 8 and 9 , when joining the current collecting bundle part 12 to the lead 17, the joining tip 47 is brought into contact with the part to be joined in a state in which the protruding base 52 and one or more protrusions 53 protrude toward the part to be joined. Therefore, when the part to be joined is being joined, the protruding direction of the protruding base 52 is along the thickness direction of the electrode group 2, and the protruding base 52 protrudes from the base 51 toward the side where the lead 17 is located (the side indicated by arrow C1). When joining the current collecting bundle part 12 to the lead 17, the joining tip 47 is brought into contact with the part to be joined in a state in which the width direction (direction indicated by arrow H) of the protruding base 52 is along the width direction (direction indicated by arrow W) of the electrode group, and the depth direction (directions indicated by arrows D1 and D2) of the protruding base 52 is along the length direction (directions indicated by arrows L1 and L2) of the electrode group. The joining tip portion 47 comes into contact with the part to be joined with the base side portion (first base side portion) 57 of the protruding base portion 52 facing the side from which the current collecting bundle portion 12 protrudes (the side of the arrow L1).

[0068] When joining the current collecting bundle part 12 to the lead 17, pressure is applied to at least one of the joining jig 41 and the stage 42, so that the pedestal 56 and one or more protrusions 53 of the joining tip 47 come into contact with the parts to be joined. Then, while the pedestal 56 and one or more protrusions 53 of the joining tip 47 are in contact with the parts to be joined, ultrasonic vibrations are transmitted to the parts to be joined through the joining tip 47, so that the parts to be joined are joined by ultrasonic welding. By joining the lead 17 to the current collecting bundle part 12 as described above, at the joint between the lead 17 and the current collecting bundle part 12, a groove bottom 26 of the groove 23 is formed at the part where the pedestal 56 comes into contact, and a recess 33 is formed at each of the parts where one or more protrusions 53 come into contact.

[0069] In this embodiment, the base portion 56 and one or more protrusions 53 are brought into contact with the portion to be joined in a state in which the base portion 56 does not protrude beyond the lead 17 on the side in the length direction of the electrode group 2 from which the current collecting bundle portion 12 protrudes. As a result, at the joint portion between the lead 17 and the current collecting bundle portion 12, the groove portion 23 is formed in a state in which it does not protrude beyond the lead 17 on the side in the length direction of the electrode group 2 from which the current collecting bundle portion 12 protrudes.

[0070] In a preferred example, the base 65 and one or more protrusions 53 are brought into contact with the portion to be joined in a state in which the base 56 does not protrude beyond the lead 17 on the side opposite to the side from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2. In this case, at the joint portion between the lead 17 and the current collecting bundle portion 12, the groove 23 is formed in a state in which it does not protrude beyond the lead 17 on either the side from which the current collecting bundle portion 12 protrudes or the side opposite to the side from which the current collecting bundle portion 12 protrudes.

[0071] In one example, the parts to be joined are joined as described above using the joining tip 47 shown in Fig. 7. As a result, grooves 23 and recessed structures 30 similar to those shown in Figs. 3 to 5 are formed in the joint portion between the current collecting bundle part 12 and the lead 17. In this embodiment, in the joining jig 41 used for joining, the pedestal 56 is adjacent to at least one of the one or more protrusions 53 in the width direction of the protruding base 52. Therefore, in the joint portion between the current collecting bundle part 12 and the lead 17, the groove bottom 26 of the groove 23 is adjacent to at least one of the one or more recesses 33 in the width direction of the electrode group 2.

[0072] In another example, in a joining jig 41 used to join the parts to be joined, the pedestal portion 56 does not protrude from the convex structure portion 50 toward the side where the pedestal side portion (first pedestal side portion) 57 faces. In this example, in the joining portion of the current collecting bundle portion 12 and the lead 17, the groove portion 23 can be formed so that the groove portion 23 does not protrude from the concave structure portion 30 toward the side where the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2. In another example, in a joining jig 41 used for joining, the pedestal portion 56 does not protrude from the convex structure portion 50 toward either the side where the pedestal side portion (first pedestal side portion) 57 faces or the side where the pedestal side portion (second pedestal side portion) 58 faces. In this example, at the joint between the current collecting bundle portion 12 and the lead 17, the groove portion 23 can be formed so that the groove portion 23 does not protrude into the recessed structure portion 30 on either the side where the current collecting bundle portion 12 protrudes or the side opposite to the side where the current collecting bundle portion 12 protrudes.

[0073] In one example, one or more recesses 33 are formed with a recession amount that does not reach the leads 17 during bonding. In this case, a bonding jig 41 is used for bonding in which the protrusion length X2 of one or more protrusions 53 from the base 51 is greater than the thickness T2 of the part to be bonded excluding the leads 17. This prevents the base 51 (base surface 55) of the bonding tip portion 47 from contacting the part to be bonded during bonding of the part to be bonded.

[0074] In either case where the recessed amount of each of the one or more recesses 33 does not reach the leads 17, or where the recessed amount reaches the leads 17, a joining jig 41 is used in which the protrusion length X2 of one or more protrusions 53 from the base 51 is greater than the recessed amount of the recess 33. This prevents the base 51 (base surface 55) of the joining tip portion 47 from coming into contact with the parts to be joined when the parts to be joined are joined.

[0075] As described above, in this embodiment, the joining jig 41 is used to join the parts to be joined, in which the pedestal portion 56 forms the protruding end of the protruding base portion 52 that protrudes from the base portion 51, and in which each of the one or more protrusions 53 further protrudes from the pedestal portion 56 in the protruding direction of the protruding base portion 52. In joining the parts to be joined, the pedestal portion 56 and the one or more protrusions 53 of the joining jig 41 are brought into contact with the parts to be joined from the side opposite to the side on which the leads 17 are stacked in the thickness direction of the electrode group 2. By joining the current collecting bundle part 12 to the leads 17 with the pedestal portion 56 in contact with the parts to be joined, the joining strength of the joint is improved.

[0076] Furthermore, in this embodiment, the pedestal portion 56 and one or more protrusions 53 are brought into contact with the parts to be joined in a state in which the pedestal portion 56 does not protrude from the lead 17 toward the side where the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2. As a result, during joining, the portion where the pedestal portion 56 contacts the parts to be joined is somewhat spaced inward in the longitudinal direction of the electrode group 2 from the protruding end E1 of the current collecting bundle portion 12. As described above, the contact of the pedestal portion 56 with the parts to be joined effectively prevents excessive expansion of the joint toward the side where the current collecting bundle portion 12 protrudes due to joining. In other words, inappropriate deformation of the joint portion, including the current collecting bundle portion 12, due to joining is appropriately suppressed. Therefore, during joining of the current collecting bundle portion 12 of the electrode group 2 to the lead 17, the joint strength at the joint portion is improved while inappropriate deformation of the joint portion due to joining is suppressed.

[0077] For example, by suppressing excessive expansion of the joint portion toward the side where the current collecting bundle portion 12 protrudes, when the electrode group 2, the leads 17, etc. are stored in the internal cavity 10 of the outer casing 5, the joint portion of the current collecting bundle portion 12 and the leads 17 is less likely to interfere with the outer casing 5. This makes it easier to insert an assembly including the electrode group 2, the leads 17, etc. into the internal cavity 10 when storing the electrode group 2, the leads 17, etc. in the internal cavity 10 of the outer casing 5. Therefore, when manufacturing the battery 1, the efficiency of the operation of storing the electrode group 2 and the leads 17 in the internal cavity 10 is improved.

[0078] Furthermore, in a preferred example of this embodiment, a joining jig 41 or the like is used for joining, in which the base portion 56 does not protrude beyond the convex structure portion 50 toward the side toward which the base side portion 57 faces, and the groove portion 23 is formed in the joining portion so that the groove portion 23 does not protrude beyond the concave structure portion 30 toward the side toward which the current collecting bundle portion 12 protrudes. This more effectively prevents the joining portion from excessively expanding toward the side toward which the current collecting bundle portion 12 protrudes due to joining. Therefore, inappropriate deformation of the joining portion due to joining is more appropriately suppressed.

[0079] Furthermore, in a preferred example of this embodiment, the base 65 and one or more protrusions 53 are brought into contact with the parts to be joined in a state in which the base 56 does not protrude beyond the lead 17 on the side opposite to the side from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2. This further appropriately suppresses inappropriate deformation of the joining part due to joining.

[0080] In a more preferred example of this embodiment, a joining jig 41 or the like is used for joining so that the base portion 56 does not protrude from the convex structure portion 50 on either the side facing the base side portion 57 or the side facing the base side portion 58. Then, in the joining portion, the groove portion 23 is formed so that the groove portion 23 does not protrude from the concave structure portion 30 on either the side facing the current collecting bundle portion 12 or the side opposite to the side facing the current collecting bundle portion 12. This further appropriately suppresses inappropriate deformation of the joining portion due to joining.

[0081] In one example of this embodiment, a joining jig 41 is used for joining, in which the pedestal portion 56 is adjacent to at least one of the protrusions 53 in the width direction of the protruding base portion 52. In the joining portion of the current collecting bundle portion 12 and the lead 17, the groove bottom 26 of the groove portion 23 is adjacent to at least one of the one or more recesses 33 in the width direction of the electrode group 2. By configuring the joining jig 41 in this manner, the pedestal portion 56 can be formed in the joining jig 41 without protruding from the convex structure portion 50 on either one side or the other in the depth direction of the protruding base portion 52. This makes it possible to form the groove portion 23 (groove bottom 26) in the joining portion without protruding from the concave structure portion 30 on either one side or the other in the length direction of the electrode group 2.

[0082] (Variation) In the first modified example shown in FIG. 10 and the second modified example shown in FIG. 11 , a groove 23 and one or more recesses 33 are formed at the joint between the current collecting bundle part 12 and the lead 17. The groove 23 does not extend beyond the lead 17 toward the side of the electrode group 2 from which the current collecting bundle part 12 protrudes in the longitudinal direction of the electrode group 2. FIGS. 10 and 11 schematically show an example of the joint (connection) between one current collecting bundle part 12 and the lead 17 of the electrode group 2 and the configuration of the surrounding area. FIGS. 10 and 11 show the electrode group 2 viewed from one side in the thickness direction (the depth direction of the battery 1 and the stacking direction of the multiple current collecting band parts 13), and also show the electrode group 2 viewed from the opposite side to the side where the leads 17 (leg plate parts 22) are stacked in the thickness direction.

[0083] In a preferred example of the first and second modified examples, the grooves 23 do not protrude from the lead 17 on the side opposite to the side from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2. Also, in the first and second modified examples, the recessed structure 30 is composed of a plurality of recesses 33. The recessed structure 30 has a recessed portion row 35 formed therein, in which the plurality of recesses 33 are aligned along the width direction of the electrode group 2, and only one recessed portion row 35 is formed. As in the first embodiment and the like, in the recessed structure 30 (recessed portion row 35), the plurality of recesses 33 are not misaligned or are barely misaligned with each other in the longitudinal direction of the electrode group 2.

[0084] In a preferred example of the first and second modified examples, the grooves 23 (groove bottoms 26) do not protrude from any of the recesses 33 forming the recessed structure 30 (recess row 35) toward the side from which the current collecting bundle portion 12 protrudes (outside in the longitudinal direction of the electrode group 2), and do not protrude from the recessed structure 30 toward the side from which the current collecting bundle portion 12 protrudes. In a more preferred example of these modified examples, the grooves 23 do not protrude from any of the recesses 33 forming the recessed structure 30 (recess row 35) toward the side from which the current collecting bundle portion 12 protrudes, and do not protrude from the opposite side from the side from which the current collecting bundle portion 12 protrudes (inside in the longitudinal direction of the electrode group 2). In this case, the grooves 23 do not protrude from the recessed structure 30 to either one side or the other side in the longitudinal direction of the electrode group 2.

[0085] As shown in FIG. 10 and other figures, in the first modified example, the groove bottoms 26 of the grooves 23 extend between adjacent recesses 33 in the recess row 35 in the width direction of the electrode group 2. Therefore, the groove bottoms 26 of the grooves 23 extend between two recesses 33 spaced apart in the width direction. However, in the first modified example, the groove bottoms 26 are not formed in an area outside the recess row 35 in the width direction of the electrode group 2. In other words, the groove bottoms 26 (grooves 23) are not formed in an area outside the recess row 35 in the width direction of the electrode group 2. However, in this modified example, as described above, the groove bottoms 26 of the grooves 23 extend between two recesses 33 spaced apart in the width direction of the electrode group 2. Due to this configuration, in this modified example, the groove bottoms 26 are adjacent to at least one of the recesses 33 constituting the recessed structure 30 in the width direction of the electrode group 2.

[0086] As shown in FIG. 11 and other figures, in the second modified example, in the recess row 35, the multiple recesses 33 are arranged continuously in the width direction of the electrode group 2. Therefore, in the recess row 35, no groove bottoms 26 are formed between the recesses 33 adjacent to each other in the width direction of the electrode group 2. However, in this modified example, as in the first embodiment and other figures, the groove bottoms 26 of the grooves 23 are adjacent to the recess row 35 from the outside in the width direction of the electrode group 2, and are adjacent to the recessed structure 30 composed of the multiple recesses 33 from the outside in the width direction of the electrode group 2. Due to this configuration, in this modified example, the groove bottoms 26 are adjacent to at least one of the recesses 33 constituting the recessed structure 30 in the width direction of the electrode group 2.

[0087] In the first and second modified examples, a joining jig 41 is used to join the current collecting bundle part 12 to the lead 17, in which the pedestal part 56 forms the protruding end of the protruding base part 52 that protrudes from the base part 51 and in which one or more protrusions 53 each protrude further from the pedestal part 56 in the protruding direction of the protruding base part 52. Then, joining is performed in the same manner as in the first embodiment, etc. In these modified examples, during joining, the pedestal part 56 and the one or more protrusions 53 are brought into contact with the part to be joined, in a state in which the pedestal part 56 does not protrude from the lead 17 toward the side in the longitudinal direction of the electrode group 2 from which the current collecting bundle part 12 protrudes. Then, at the joining portion between the lead 17 and the current collecting bundle part 12, the groove bottom 26 of the groove part 23 is formed at the part where the pedestal part 56 is in contact, and a recess 33 is formed at each of the parts where one or more protrusions 53 are in contact.

[0088] In the joining jig 41 used in the first and second modified examples, the base portion 56 is adjacent to at least one of the protrusions 53 constituting the convex structure portion 50 in the width direction of the protruding base portion 52. As in the first embodiment and the like, the convex structure portion 50 of the joining jig 41 has a protrusion row 63 formed therein in which multiple protrusions 53 are aligned along the width direction of the protruding base portion 52, and only one protrusion row 63 is formed. As in the first embodiment and the like, in the convex structure portion 50 (protrusion row 63), the multiple protrusions 53 are not misaligned or are barely misaligned with each other in the depth direction of the protruding base portion 52.

[0089] In a preferred example of the joining jigs 41 of the first and second modified examples, the base portion 56 does not protrude toward the side toward which the base side portion (first base side portion) 57 faces, relative to any of the protrusions 53 that form the convex structure 50 (protrusion row 63), and does not protrude toward the side toward which the base side portion 57 faces, relative to the convex structure 50. Furthermore, in a more preferred example of the joining jigs 41 of these modified examples, the base portion 56 does not protrude toward the side toward which the base side portion 57 faces, relative to any of the protrusions 53 that form the convex structure 50 (protrusion row 63), and does not protrude toward the side toward which the base side portion (second base side portion) 58 faces. In this case, the base portion 56 does not protrude toward either one side or the other of the protruding base portion 52 in the depth direction, relative to the convex structure 50.

[0090] In one modified example, the recessed structure 30 is formed of only one recess 33 at the joint between the current collecting bundle part 12 and the lead 17. In this modified example, the groove part 23 does not protrude from the lead 17 toward the side from which the current collecting bundle part 12 protrudes in the length direction of the electrode group 2. In this modified example as well, in a preferred example, the groove part 23 does not protrude from the lead 17 toward the side opposite to the side from which the current collecting bundle part 12 protrudes in the length direction of the electrode group 2.

[0091] Furthermore, in a preferred example of this modified example, the grooves 23 (groove bottoms 26) do not protrude from the recesses 33 that form the recessed structure 30 toward the side from which the current collecting bundle portions 12 protrude (outside in the longitudinal direction of the electrode group 2). With this configuration, the grooves 23 do not protrude from the recessed structure 30 toward the side from which the current collecting bundle portions 12 protrude. Furthermore, in a more preferred example of this modified example, the grooves 23 do not protrude from the recesses 33 that form the recessed structure 30 toward the side from which the current collecting bundle portions 12 protrude, and do not protrude from the side opposite the side from which the current collecting bundle portions 12 protrude (inside in the longitudinal direction of the electrode group 2). With this configuration, the grooves 23 do not protrude from the recessed structure 30 to either one side or the other side in the longitudinal direction of the electrode group 2.

[0092] In this modified example, the groove bottom 26 is adjacent to the only recess 33 provided in the width direction of the electrode group 2. In one example, the groove bottom 26 is adjacent to the recess 33 only from one side in the width direction, and in another example, the groove bottom 26 is adjacent to the recess 33 from both sides in the width direction. By adopting such a configuration, in this modified example as well, the groove bottom 26 is adjacent to at least one of the recesses 33 that constitute the recessed structure 30 in the width direction of the electrode group 2.

[0093] In this modified example, the current collecting bundle part 12 is joined to the lead 17 in the same manner as in the above-described embodiment, except that a joining jig 41 is used in which only one protrusion 53 protrudes from the pedestal part 56. In this modified example, the pedestal part 56 and the protrusion 53 are brought into contact with the part to be joined, in a state in which the pedestal part 56 does not protrude from the lead 17 on the side in the length direction of the electrode group 2 from which the current collecting bundle part 12 protrudes. Then, at the joint portion between the lead 17 and the current collecting bundle part 12, the groove bottom 26 of the groove part 23 is formed at the part where the pedestal part 56 is in contact, and the recess 33 is formed at the part where the protrusion 53 is in contact.

[0094] In the joining jig 41 used in this modification, the pedestal portion 56 is adjacent to the protrusion 53 that constitutes the convex structure portion 50 in the width direction of the protruding base portion 52. In one example, the pedestal portion 56 is adjacent to the protrusion 53 only from one side in the width direction, and in another example, the pedestal portion 56 is adjacent to the protrusion 53 from both sides in the width direction. By adopting such a configuration, in this modification as well, the pedestal portion 56 is adjacent to at least one of the protrusions 53 that constitute the convex structure portion 50 in the width direction of the protruding base portion 52.

[0095] In a preferred example of the joining jig 41 of this modified example, the base portion 56 does not protrude from the side of the base lateral portion (first base lateral portion) 57 that faces the protrusion 53 that forms the convex structure 50. With this configuration, the base portion 56 does not protrude from the side of the base lateral portion 57 that faces the convex structure 50. Furthermore, in a more preferred example of the joining jig 41 of this modified example, the base portion 56 does not protrude from the side of the base lateral portion 57 that faces the protrusion 53 that forms the convex structure 50, and does not protrude from the side of the base lateral portion (second base lateral portion) 58 that faces. In this case, the base portion 56 does not protrude from the convex structure 50 to either one side or the other of the protruding base portion 52 in the depth direction.

[0096] 12 and 13 , a groove 23 and one or more recesses 33 are also formed at the joint between the current collecting bundle part 12 and the lead 17. The groove 23 does not protrude from the lead 17 toward the side from which the current collecting bundle part 12 protrudes in the length direction of the electrode group 2. In a preferred example of this modification, the groove 23 also does not protrude from the lead 17 toward the side opposite the side from which the current collecting bundle part 12 protrudes in the length direction of the electrode group 2.

[0097] 12 and 13 schematically show an example of the joint (connection) portion of one current collecting bundle portion 12 of the electrode group 2 to the lead 17, and the configuration of the vicinity thereof. Fig. 12 shows the electrode group 2 as viewed from one side in the thickness direction (the depth direction of the battery 1 and the stacking direction of the multiple current collecting bundle portions 13), and also shows the electrode group 2 as viewed from the opposite side to the side where the leads 17 (leg plate portions 22) are stacked in the thickness direction. Fig. 13 shows a cross section taken along imaginary line A3 in Fig. 12, and shows a cross section perpendicular or substantially perpendicular to the width direction of the electrode group 2 (the height direction of the battery 1).

[0098] In this modification, as in the first embodiment and the like, the recessed structure 30 is composed of a plurality of recesses 33. The groove bottom 26 is adjacent to at least one of the recesses 33 constituting the recessed structure 30 in the width direction of the electrode group 2. Also, in this modification, as in the first embodiment and the like, the recessed structure 30 has recess rows 35A and 35B in which a plurality of recesses 33 are aligned along the width direction of the electrode group 2. However, in this modification, a plurality of recess rows 35A and 35B are formed, and the recess rows 35A and 35B are shifted relative to each other in the longitudinal direction of the electrode group 2. Due to this configuration, in this modification, one or more of the plurality of recesses 33 are shifted relative to any of the other recesses 33 in the longitudinal direction of the electrode group 2. Therefore, in one or more of the plurality of recesses 33, the distance from the protruding end E1 of the current collecting bundle portion 12 along the longitudinal direction of the electrode group 2 is different from that of any of the other recesses 33.

[0099] Here, among the plurality of recesses 33, a recess (proximal recess) 33M closest to the protruding end E1 of the current collecting bundle portion 12 and a recess (distalmost recess) 33N farthest from the protruding end E1 of the current collecting bundle portion 12 are defined. In a configuration in which one or more of the plurality of recesses 33 are shifted in the longitudinal direction of the electrode group 2 relative to any of the other recesses 33 as in this modified example, the plurality of recesses 33 include one or more recesses 33M and one or more recesses 33N. Furthermore, depending on the arrangement of the plurality of recesses 33 constituting the recessed structure portion 30, at least one of the recesses 33M and 33N may be present in plural. In the example of FIGS. 12 and 13 , in the recessed structure portion 30, three recesses 33 forming the recessed portion row 35A are recesses (proximal recess) 33M, and three recesses 33 forming the recessed portion row 35B are recesses (distalmost recess) 33N. The recess (most proximal recess) 33M is also referred to as a "first recess", and the recess (most distal recess) 33N is also referred to as a "second recess".

[0100] In a preferred example of this modified example, the groove 23 (groove bottom 26) does not protrude toward the side from which the current collecting bundle portion 12 protrudes (outside in the longitudinal direction of the electrode group 2) relative to one or more recesses 33 that form the recess (closest recess) 33M. For example, in the example of FIGS. 12 and 13 , the groove 23 does not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to any of the three recesses 33 that form the recess row 35A. With this configuration, the groove 23 does not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to the recessed structure 30. Note that in the recessed structure 30 of this modified example, for example, the position through which the virtual line α3 (see FIG. 12 ) passes is the end on the side from which the current collecting bundle portion 12 protrudes.

[0101] Furthermore, in a more preferred example of this modified example, the grooves 23 do not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to one or more recesses 33 that form recess 33M, and do not protrude toward the opposite side from the side from which the current collecting bundle portion 12 protrudes (inward in the longitudinal direction of the electrode group 2) relative to one or more recesses 33 that form recess (furthest recess) 33N. For example, in the example of FIGS. 12 and 13 , the grooves 23 do not protrude toward the side from which the current collecting bundle portion 12 protrudes relative to any of the three recesses 33 that form recess row 35A, and the grooves 23 do not protrude toward the opposite side from the side from which the current collecting bundle portion 12 protrudes relative to any of the three recesses 33 that form recess row 35B. With this configuration, the grooves 23 do not protrude toward either one side or the other in the longitudinal direction of the electrode group 2 relative to the recessed structure portion 30. In the recessed structure 30 of this modified example, for example, the position where the imaginary line α4 (see FIG. 12) passes is the end opposite to the side where the current collecting bundle portion 12 protrudes.

[0102] In addition, in this modified example, the groove bottom 26 of the groove portion 23 extends between recessed portion rows 35A and 35B that are adjacent in the longitudinal direction of the electrode group 2. Therefore, in this modified example, the multiple recessed portions 33 that make up the recessed structure 30 include two recessed portions 33 that are spaced apart in the longitudinal direction of the electrode group 2. The groove bottom 26 of the groove portion 23 extends between the two recessed portions 33 that are spaced apart in the longitudinal direction.

[0103] 14 is a perspective view schematically illustrating an example of the configuration of a joining tip portion 47 of a joining jig 41 according to a third modified example. As shown in FIG. 14 and other figures, this modified example also uses a joining jig 41 in which a pedestal portion 56 forms the protruding end of a protruding pedestal portion 52 that protrudes from a base portion 51, and in which one or more protrusions 53 each protrude further from the pedestal portion 56 in the protruding direction of the protruding pedestal portion 52. The joining jig 41 is used to join the current collecting bundle portion 12 to the lead 17. Then, joining is performed in the same manner as in the above-described embodiment. In this modified example, the pedestal portion 56 and one or more protrusions 53 are brought into contact with the part to be joined in a state in which the pedestal portion 56 does not protrude beyond the lead 17 on the side of the electrode group 2 in the longitudinal direction from which the current collecting bundle portion 12 protrudes. At the joint between the lead 17 and the current collecting bundle portion 12, the groove bottom 26 of the groove portion 23 is formed at the portion where the base portion 56 is in contact, and a recess 33 is formed at each portion where one or more protrusions 53 are in contact.

[0104] In the joining jig 41 used in this modification, the base portion 56 is adjacent to at least one of the protrusions 53 constituting the convex structure portion 50 in the width direction of the protruding base portion 52. Furthermore, similar to the first embodiment, the convex structure portion 50 of the joining jig 41 has protrusion rows 63A and 63B in which multiple protrusions 53 are aligned along the width direction of the protruding base portion 52. However, in this modification, multiple protrusion rows 63A and 63B are formed, and the multiple protrusion rows 63A and 63B are arranged offset from each other in the depth direction of the protruding base portion 52. Due to this configuration, in this modification, one or more of the multiple protrusions 53 are arranged offset from any of the other protrusions 53 in the depth direction of the protruding base portion 52. Therefore, the distance from the base side portion 57 of one or more of the multiple protrusions 53 along the depth direction of the protruding base portion 52 is different from that of any of the other protrusions 53.

[0105] Here, among the multiple protrusions 53, a protrusion (proximal-most protrusion) 53M closest to the base side portion (first base side portion) 57 and a protrusion (distal-most protrusion) 53N farthest from the base side portion 57 are defined. In a configuration in which one or more of the multiple protrusions 53 are shifted in the depth direction of the protruding base portion 52 relative to one of the other protrusions 53, as in this modified example, there are one or more protrusions 53M and one or more protrusions 53N among the multiple protrusions 53. Furthermore, depending on the arrangement of the multiple protrusions 53 constituting the convex structure portion 50, there may be a plurality of at least one of the protrusions 53M and 53N. In the example of FIG. 14 , in the convex structure portion 50, the three protrusions 53 forming the protrusion row 63A are the protrusions (proximal-most protrusions) 53M, and the three protrusions 53 forming the protrusion row 63B are the protrusions (distal-most protrusions) 53N. The protrusions 53M are also referred to as the “first protrusions,” and the protrusions 53N are also referred to as the “second protrusions.” Among the plurality of protrusions 53, the protrusion 53M is farthest from the base side portion (second base side portion) 58, and the protrusion 53N is closest to the base side portion 58.

[0106] In a preferred example of this modification, the base portion 56 does not protrude toward the side of the base side portion 57 of one or more protrusions 53 that become the protrusion (most protrusion) 53M. For example, in the example of FIG. 14 , the base portion 56 does not protrude toward the side of the base side portion 57 of any of the three protrusions 53 that form the protrusion row 63A. With this configuration, the base portion 56 does not protrude toward the side of the base side portion 57 of the convex structure portion 50. Furthermore, in each of the one or more protrusions 53 that become the protrusion 53M, the protrusion side portion (first protrusion side portion) 61 is connected to the base side portion (first base side portion) 57 of the protruding base portion 52 without the base portion 56 therebetween. Note that, in the convex structure portion 50 of this modification, for example, the position through which the virtual line β3 (see FIG. 14 ) passes is the end toward the side toward which the base side portion 57 faces.

[0107] Furthermore, in a more preferred example of this modified example, the base portion 56 does not protrude toward the side of the base side portion 57 facing one or more protrusions 53 that become the protrusion 53M, and does not protrude toward the side of the base side portion 58 facing (the side opposite to the side of the base side portion 57 facing) toward one or more protrusions 53 that become the protrusion (distalmost protrusion) 53N. For example, in the example of FIG. 14 , the base portion 56 does not protrude toward the side of the base side portion 57 facing any of the three protrusions 53 that form the protrusion row 63A, and the base portion 56 does not protrude toward the side of the base side portion 58 facing any of the three protrusions 53 that form the protrusion row 63B. With this configuration, the base portion 56 does not protrude toward either one side or the other of the protruding base portion 52 in the depth direction relative to the convex structure portion 50. Furthermore, in each of the one or more protrusions 53 that become protrusions 53M, the protrusion side portion 61 is connected to the base side portion 57 of the protruding base portion 52 without the base portion 56 therebetween. In each of the one or more protrusions 53 that become protrusions 53N, the protrusion side portion (second protrusion side portion) 62 is connected to the base side portion (second base side portion) 58 of the protruding base portion 52 without the base portion 56 therebetween. In the convex structure portion 50 of this modified example, for example, the position through which the virtual line β4 (see FIG. 14) passes is the end toward which the base side portion 58 faces.

[0108] In one modified example, the recessed structure 30 has three or more recessed portion rows 35 formed therein, each row including a plurality of recessed portions 33 aligned along the width direction of the electrode group 2. In this case, one or more of the plurality of recessed portions 33 are also shifted in the longitudinal direction of the electrode group 2 relative to any of the other recessed portions 33. In this modified example, the recessed portions 33M and 33N are defined in the same manner as in the third modified example. Then, a groove 23 and one or more recessed portions 33 are formed at the joint between the current collecting portion 12 and the lead 17 in the same manner as in any of the examples described above in the third modified example. However, in either case, the groove 23 does not extend beyond the lead 17 toward the side of the electrode group 2 from which the current collecting portion 12 protrudes in the longitudinal direction.

[0109] In this modification, the joining jig 41 has three or more protrusion rows 63, each row including a plurality of protrusions 53 aligned along the width direction of the protruding base portion 52. In this case, one or more of the plurality of protrusions 53 are also shifted in the depth direction of the protruding base portion 52 relative to any of the other protrusions 53. In this modification, the protrusions 53M and 53N are defined in the same manner as in the third modification. The joining tip portion 47 is formed with a pedestal 56 and one or more protrusions 53 in the same manner as in any of the examples described above in the third modification. However, in either case, when joining the current collecting bundle portion 12 to the lead 17, the pedestal 56 and one or more protrusions 53 are brought into contact with the joining target portion in a state in which the pedestal 56 does not protrude beyond the lead 17 toward the side of the electrode group 2 from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2.

[0110] In another modified example, in a configuration in which a recessed portion row 35 in which a plurality of recessed portions 33 are aligned along the width direction of the electrode group 2 is not formed in the recessed structure portion 30, one or more of the plurality of recessed portions 33 are arranged offset in the length direction of the electrode group 2 relative to any of the other recessed portions 33. In this modified example, recessed portions 33M and 33N are defined in the same manner as in the third modified example. Then, a groove portion 23 and one or more recessed portions 33 are formed at the joint portion of the current collecting portion 12 and the lead 17 in the same manner as in any of the examples described above in the third modified example. However, in either case, the groove portion 23 does not protrude from the lead 17 toward the side of the electrode group 2 in the length direction from which the current collecting portion 12 protrudes.

[0111] Furthermore, in this modified example, the joining jig 41 does not have a projection row 63 in which multiple projections 53 are aligned along the width direction of the protruding base portion 52. However, in this modified example, one or more of the multiple projections 53 are also positioned offset in the depth direction of the protruding base portion 52 relative to any of the other projections 53, and projections 53M, 53N are defined in the same manner as in the third modified example. Then, a pedestal portion 56 and one or more projections 53 are formed on the joining tip portion 47 in the same manner as in any of the examples described above in the third modified example. However, in either case, when joining the current collecting bundle portion 12 to the lead 17, the pedestal portion 56 and one or more projections 53 are brought into contact with the part to be joined in a state in which the pedestal portion 56 does not protrude beyond the lead 17 on the side from which the current collecting bundle portion 12 protrudes in the longitudinal direction of the electrode group 2.

[0112] In another modified example, a plurality of current collecting bundle portions 12 are formed in each of the pair of uncoated portions 11. In this case, in each of the pair of uncoated portions 11, the plurality of current collecting bundle portions 12 are formed spaced apart from each other in the thickness direction of the electrode group 2. Even when a plurality of current collecting bundle portions 12 are formed in each of the uncoated portions 11, each of the current collecting bundle portions 12 protrudes to one side in the longitudinal direction of the electrode group 2, and in each current collecting bundle portion 12, the plurality of current collecting band portions 13 are stacked in the thickness direction of the electrode group 2. In this modified example, a plurality of leg plate portions 22 are provided in each of the leads 17, and each of the leads 17 is provided with the same number of leg plate portions 22 as the number of current collecting bundle portions 12 formed in the uncoated portions 11 to be connected. In this modified example, each of the current collecting bundle portions 12 is joined to a corresponding one of the pair of leads 17 by a corresponding one of the leg plate portions 22. In this modification, each of the current collecting bundle portions 12 is joined to the leg plate portion 22 in the same manner as in any of the above-described embodiments.

[0113] In one modified example, the battery 1 is not provided with a clip 18, and no clip 18 is attached to each of the current collecting bundle parts 12. In this case, in each of the uncoated portions 11, the current collecting bundle part 12 is directly joined (connected) to a corresponding one of a pair of leads 17. In this modified example, a groove 23 opens on the outer surface of the current collecting bundle part 12 on the side opposite to the side on which the leads 17 are stacked in the thickness direction of the electrode group 2. In this modified example, each of the current collecting bundle parts 12 is joined to a lead 17 in the same manner as in any of the above-described embodiments.

[0114] In addition, in the above-described embodiment, the exterior part 3 is composed of the exterior container 5 and the lid member 6, but the configuration of the exterior part 3 is not limited to this. In one modified example, the exterior part 3 is composed of a laminate film.

[0115] In addition, in one example such as FIG. 1 , the pair of uncoated portions 11 protrude to opposite sides in the length direction of the electrode group 2, but this is not limited thereto. In one modified example, in the electrode group 2, the negative electrode uncoated portion protrudes toward the side in the length direction from which the positive electrode uncoated portion protrudes. In this case, the pair of uncoated portions 11 are spaced apart from each other in the width direction of the electrode group and do not contact each other. In one example of this modified example, the electrode group 2 is placed in the internal cavity 10 of the outer container 5 with the thickness direction of the electrode group 2 aligned with the depth direction of the battery 1, the length direction of the electrode group 2 aligned with the height direction of the battery 1, and the width direction of the electrode group 2 aligned with the lateral direction of the battery 1. In the internal cavity 10, the pair of uncoated portions 11 (the positive electrode uncoated portion and the negative electrode uncoated portion) protrude toward the side in the height direction of the battery 1 where the lid member 6 is located. In this modification, the current collecting bundle portion 12 is joined to the lead 17 in each of the uncoated portions 11 in the same manner as in any of the above-described embodiments.

[0116] In any of the modified examples described above, at the joint portion of the current collecting bundle portion 12 to the lead 17, the groove portion 23 does not protrude from the lead 17 toward the side where the current collecting bundle portion 12 protrudes in the length direction of the electrode group 2. When joining the current collecting bundle portion 12 to the lead 17, the base portion 56 and one or more protrusions 53 are brought into contact with the part to be joined in a state where the base portion 56 does not protrude from the lead 17 toward the side where the current collecting bundle portion 12 protrudes in the length direction of the electrode group 2.

[0117] Furthermore, in the electrode group 2, at least one of the pair of uncoated portions 11, i.e., at least one of the positive electrode uncoated portion and the negative electrode uncoated portion, may be joined to the lead 17 in the same manner as in any of the above-described embodiments, etc. In other words, one or more of the pair or more current collecting bundle portions 12 formed in the electrode group 2 may be joined to the lead 17 in the same manner as in any of the above-described embodiments, etc.

[0118] According to at least one of these embodiments or examples, the groove recesses to the groove bottom toward the lead's side in the thickness direction at the joint between the lead and the current collecting bundle part, and does not protrude toward the lead's longitudinal side. Each of the one or more recesses recesses further from the groove bottom toward the lead's side. This makes it possible to provide a battery, a joining jig, a joining device, and a battery manufacturing method that can improve the joint strength at the joint when joining the current collecting bundle part of the electrode group to the lead, while suppressing inappropriate deformation of the joint due to joining.

[0119] 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. [Explanation of symbols]

[0120] 1...battery, 2...electrode group, 3...exterior part, 11...uncoated part, 12...current collecting bundle part, 13...current collecting band part, 17...lead, 23...groove part, 26...groove bottom part, 30...recessed structure part, 33...recess, 40...bonding device, 41...bonding jig, 42...stage, 43...ultrasonic vibrator, 45...pressure part, 50...convex structure part, 51...base part, 52...protruding base part, 53...protrusion, 56...base part, 57...base side part (first base side part), 58...base side part (second base side part), E1...protruding end.

Claims

1. an electrode group including a current collecting bundle portion protruding to one side in the longitudinal direction; a lead that is conductive and is joined to the current collecting bundle portion in a state where the lead is stacked on the current collecting bundle portion from one side in a thickness direction of the electrode group that intersects with the length direction; a groove portion having a groove bottom portion, the groove portion being recessed to the groove bottom portion toward the side where the lead is located in the thickness direction at a joint portion between the lead and the current collecting bundle portion, and not protruding toward the side where the current collecting bundle portion protrudes in the length direction relative to the lead; one or more recesses each recessed from the groove bottom toward the lead; A battery comprising:

2. The battery according to claim 1 , wherein the groove does not protrude from the recessed structure formed of the one or more recesses toward a side from which the current collecting bundle portion protrudes.

3. The battery according to claim 1 , wherein the groove bottom of the groove is adjacent to at least one of the one or more recesses in a width direction of the electrode group that intersects both the length direction and the thickness direction.

4. The battery according to claim 3 , wherein the groove bottom of the groove is adjacent to a recessed structure formed of the one or more recesses from the outside in the width direction.

5. The one or more recesses include a plurality of recesses, the plurality of recesses include two recesses spaced apart from each other in the width direction, The groove bottom of the groove portion extends between the two recessed portions spaced apart in the width direction.

4. The battery of claim 3.

6. The battery according to claim 1 , wherein the groove does not protrude from the lead to a side opposite to the side from which the current collecting bundle portion protrudes.

7. A base and a protruding base portion protruding from the base portion, the protruding base portion including a base portion forming a protruding end from the base portion, and a first base side portion extending from the base portion toward the protruding direction while facing one side in a depth direction intersecting with the protruding direction; one or more protrusions each further protruding from the base portion in the protruding direction of the protruding base portion; Equipped with A joining jig in which the base portion does not protrude toward the side of the protruding base portion toward which the first base side portion faces in the depth direction relative to the convex structure portion consisting of the one or more protrusions.

8. The joining jig according to claim 7 , wherein the base portion of the protruding base portion is adjacent to at least one of the one or more protrusions in a width direction of the protruding base portion that intersects both the protruding direction and the depth direction.

9. The joining jig according to claim 8 , wherein the base portion of the protruding base portion is adjacent to the convex structure portion from the outer side in the width direction.

10. the protruding base portion includes a second base side portion extending from the base portion toward the protruding direction and facing the opposite side to the side toward which the first base side portion faces in the depth direction, the base portion does not protrude from the protruding structure portion toward a side toward which the second base side portion faces in the depth direction of the protruding base portion, The joining jig according to claim 7.

11. The joining jig according to any one of claims 7 to 10, a stage that, in joining the current collecting bundle parts to the leads on one side in the longitudinal direction of the electrode group, sandwiches the joining target parts, where the current collecting bundle parts and the leads are stacked, between the joining jig and the stage in a state where the leads are stacked on the current collecting bundle parts from one side in the thickness direction of the electrode group that intersects with the longitudinal direction, and contacts the joining target parts from the side in the thickness direction where the leads are stacked; a pressure applying unit that applies pressure to at least one of the joining jig and the stage while the joining target parts are sandwiched between the joining jig and the stage, thereby bringing the base part of the joining jig and the one or more protrusions of the convex structure part into contact with the joining target parts in a state in which the base part does not protrude from the lead toward the side where the current collecting bundle part protrudes in the length direction; an ultrasonic vibrator that transmits ultrasonic vibrations to the parts to be joined through the joining jig in a state in which the parts to be joined are sandwiched between the joining jig and the stage; A joining device comprising:

12. In an electrode group in which a current collecting bundle portion protrudes to one side in a length direction, a lead is stacked on the current collecting bundle portion from one side in a thickness direction of the electrode group that intersects with the length direction; joining the joining target portions in which the current collecting bundle portions and the leads are stacked, using a joining jig in which a pedestal portion forms a protruding end of a protruding pedestal portion that protrudes from a base portion, and in which one or more protrusions each further protrude from the pedestal portion in a protruding direction of the protruding pedestal portion; In joining the parts to be joined, the pedestal portion and the one or more protrusions of the joining jig are brought into contact with the parts to be joined from the side opposite to the side on which the leads are stacked in the thickness direction, and the pedestal portion and the one or more protrusions are brought into contact with the parts to be joined in a state in which the pedestal portion does not protrude from the leads toward the side on which the current collecting bundle portion protrudes in the length direction; A method for manufacturing a battery, comprising:

13. In the joining jig used to join the parts to be joined, the base side portion of the protruding base portion extends from the base portion toward the protruding direction while facing one side in the depth direction of the protruding base portion that intersects with the protruding direction, and the base portion does not protrude toward the side toward which the base side portion faces in the depth direction relative to the convex structure portion composed of the one or more protrusions, When the base portion and the one or more protrusions are brought into contact with the parts to be joined, the base portion and the one or more protrusions are brought into contact with the parts to be joined in a state in which the base side portion faces a side from which the current collecting bundle portion protrudes. The method of claim 12.

14. The joining method further includes clamping the parts to be joined between the joining jig and a stage. In joining the parts to be joined, the parts to be joined are sandwiched between the joining jig and the stage, and pressure is applied to at least one of the joining jig and the stage, thereby bringing the base portion and the one or more protrusions of the joining jig into contact with the parts to be joined; In joining the parts to be joined, ultrasonic vibrations are transmitted to the parts to be joined through the joining jig in a state where the parts to be joined are sandwiched between the joining jig and the stage. The method of claim 12 or 13.

Images