Secondary battery

Abstract

A secondary battery (1) is provided with: a plurality of current collectors (50) electrically connected to a plurality of electrodes; and a terminal joined to the plurality of current collectors (50), the outer surface of the terminal in a joint (J) between the plurality of current collectors (50) and the terminal having a first concavo-convex region (R1) having a concavo-convex shape, the first concavo-convex region (R1) having: a first concavo-convex pattern (P1) having a plurality of first concavities (U1); and two second concave-convex patterns (P2) having second concave portions (U2) having a larger area than the first concave portions (U1) in plan view of the outer surfaces of the plurality of terminals, the first concave-convex pattern (P1) being located between the two second concave-convex patterns (P2) in plan view.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery. Background Art

[0002] In Patent Document 1, an ultrasonic bonding device is disclosed, which includes an anvil and a sonotrode disposed opposite to the anvil. The ultrasonic bonding device of Patent Document 1 ultrasonically bonds a plurality of objects to be bonded that are overlapped and disposed on the anvil by pressing and vibrating the objects to be bonded with the sonotrode.

[0003] In the ultrasonic bonding device of Patent Document 1, the height of the outermost protrusion among a plurality of protrusions provided on at least one of the anvil and the sonotrode is set to be smaller than the height of the inner protrusion. As a result, in the object to be bonded, generation of cracks at the boundary between the gripped area gripped by the anvil and the sonotrode and the non-gripped area not gripped by the anvil and the sonotrode is suppressed. Therefore, the strength of the joint portion of the object to be bonded is increased, and the bonding state of the joint portion can be stabilized.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-231402 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] However, in the ultrasonic bonding device of Patent Document 1, if the height of the outermost protrusion is smaller than the height of the inner protrusion, the inner protrusion wears out earlier than the outermost protrusion. As a result, if the difference in height between the inner protrusion and the outermost protrusion becomes small, cracks may occur at the boundary between the above-mentioned gripped area and non-gripped area, the strength of the joint portion decreases, and the bonding state of the joint portion may deviate. This is the same in the case where the objects to be bonded are a plurality of current collectors and terminals of a secondary battery.

[0009] The present disclosure has been made in view of the above circumstances, and an object thereof is to stabilize the bonding state between a plurality of current collectors and terminals in a secondary battery.

[0010] Technical Solution for Solving the Technical Problem

[0011] The secondary battery of the present disclosure includes: a laminate in which a plurality of electrodes are laminated; a plurality of current collectors electrically connected to the plurality of electrodes; and terminals joined to the plurality of current collectors. An outer surface of the terminal in a joint portion between the plurality of current collectors and the terminal has a concavo-convex first concavo-convex region. The first concavo-convex region has: a first concavo-convex pattern having a plurality of first concave portions; and two second concavo-convex patterns having a plurality of second concave portions with an area larger than that of the first concave portions when viewed from above the outer surface of the terminal. The first concavo-convex pattern is located between the two second concavo-convex patterns when viewed from above.

[0012] Effect of the Invention

[0013] According to the secondary battery of the present disclosure, it is possible to stabilize the joint state between the plurality of current collectors and the terminal. Description of the Drawings

[0014] Figure 1 is a top view of the secondary battery according to an embodiment of the present disclosure.

[0015] Figure 2 is along Figure 1 a cross-sectional view of the secondary battery taken along line II-II shown.

[0016] Figure 3 is a schematic diagram showing a process of joining a positive terminal and a plurality of current collectors.

[0017] Figure 4 is a top view of a support surface of an anvil.

[0018] Figure 5 is from Figure 4 a perspective view of the anvil when viewed from the direction of arrow V shown.

[0019] Figure 6 is a top view of a pressing surface of a welding head.

[0020] Figure 7 is a side view of the welding head.

[0021] Figure 8 is along Figure 6 a cross-sectional view of the welding head taken along line VIII-VIII shown.

[0022] Figure 9 is along Figure 6 a cross-sectional view of the welding head taken along line IX-IX shown.

[0023] Figure 10 is showing Figure 4 a graph showing the wear amount of the support surface in the anvil according to the embodiment of the present disclosure and the wear amount of the support surface in the anvil of the comparative example shown.

[0024] Figure 11 is a top view of the joint portion of multiple current collectors and the positive terminal as viewed from the positive terminal side.

[0025] Figure 12 is a view showing Figure 11 a partial enlarged view of the first concavo-convex region of the first concavo-convex pattern shown.

[0026] Figure 13 is a cross-sectional view of the joint portion.

[0027] Figure 14 is a view showing Figure 11 a partial enlarged view of the first concavo-convex region of the first concavo-convex pattern, the second concavo-convex pattern, and the third concavo-convex pattern shown.

[0028] Figure 15 is a top view of the joint portion of multiple current collectors and the positive terminal as viewed from the current collector side.

[0029] Figure 16 is Figure 15 an enlarged view of the second concavo-convex region shown.

[0030] Figure 17 is a cross-sectional view of the joint portion along the XVII-XVII line shown in Figure 16 Figure 16 .

[0031] Figure 18 is a cross-sectional view of the joint portion along the XVIII-XVIII line shown in Figure 16 Figure 16 .

[0032] Figure 19 is a top view of the anvil used in the joining process according to the first modification of the embodiment of the present disclosure.

[0033] Figure 20 is a view of the anvil as viewed from the arrow XX shown in Figure 19 Figure 19 .

[0034] Figure 21 is a top view of the anvil used in the joining process according to the second modification of the embodiment of the present disclosure.

[0035] Figure 22 is a top view of the anvil used in the joining process according to the third modification of the embodiment of the present disclosure.

[0036] Figure 23 is a top view of the anvil used in the joining process according to the fourth modification of the embodiment of the present disclosure.

[0037] Figure 24It is a top view of an anvil used in the bonding process according to the fifth modification of the embodiment of the present disclosure.

[0038] Figure 25 It is a top view of an anvil used in the bonding process according to the sixth modification of the embodiment of the present disclosure.

[0039] Figure 26 It is a side view of an anvil and a sonotrode according to the sixth modification of the embodiment of the present disclosure.

[0040] Figure 27 It is a top view of an anvil used in the bonding process according to the seventh modification of the embodiment of the present disclosure.

[0041] Figure 28 It is a top view of an anvil used in the bonding process according to the eighth modification of the embodiment of the present disclosure. Detailed Description of the Embodiment

[0042] Hereinafter, the embodiments will be described in detail with reference to the drawings. It should be noted that the present disclosure is not limited to this embodiment. Each embodiment is an example, and of course, partial replacement or combination of the configurations shown in different embodiments can be made.

[0043] Figure 1 It is a top view of a secondary battery according to the embodiment of the present disclosure. Figure 2 It is along Figure 1 A cross-sectional view of the secondary battery 1 taken along line II-II shown.

[0044] The secondary battery 1 is, for example, a lithium-ion battery. As Figure 1 shown, the secondary battery 1 includes a laminate 10, a positive electrode terminal 20, a negative electrode terminal 30, an outer package 40, and a current collector 50.

[0045] The laminate 10 is housed in the outer package 40. As Figure 2 shown, the laminate 10 has a laminated structure and includes a plurality of sheet-like positive electrodes 11 and negative electrodes 12, and the plurality of positive electrodes 11 and the plurality of negative electrodes 12 are alternately laminated with a separator 13 therebetween.

[0046] The positive electrode terminal 20 is a plate-like member having an L-shaped cross section with a bent surface 21, and one end including the bent surface 21 is located inside the outer package 40. The other end of the positive electrode terminal 20 is located outside the outer package 40. It should be noted that the positive electrode terminal 20 may also be an unbent plate-like member.

[0047] The positive terminal 20 is electrically connected to a plurality of positive electrodes 11 via a plurality of current collectors 50 respectively. The current collectors 50 are metal foils. The positive terminal 20 and the current collectors 50 connected to the positive terminal 20 are formed of the same metal (such as aluminum) as each other. A process of forming a joint J (details will be described below) by electrically joining the positive terminal 20 and the plurality of current collectors 50.

[0048] The negative terminal 30 has an L-shaped cross-section with a bent surface like the positive terminal 20, and one end including the bent surface is located inside the outer package 40. The other end of the negative terminal 30 is located outside the outer package 40. The negative terminal 30 is electrically connected to a plurality of negative electrodes 12 via a plurality of current collectors 50 respectively. The negative terminal 30 and the current collectors 50 connected to the negative terminal 30 are formed of the same metal (such as copper) as each other. A joint J is formed by electrically joining the negative terminal 30 and the plurality of current collectors 50 (details will be described below). It should be noted that the negative terminal 30 and the current collectors 50 connected to the negative terminal 30 may also be formed of different metals. For example, the material of the negative terminal 30 may be copper, and the materials of the current collectors 50 connected to the negative terminal 30 may be nickel, nickel-plated copper, nickel-clad copper, etc.

[0049] As Figure 1 shown, the outer package 40 has a housing portion 41 for housing the laminate 10 and a flange portion 42 around the housing portion 41. An electrolyte (such as a non-aqueous electrolyte) is housed in the housing portion 41.

[0050] The outer package 40 is formed by folding back a single sheet of film. A part of the film is formed into a convex shape by, for example, stamping to form the housing portion 41. By joining the overlapping portions of the film around the housing portion 41, the flange portion 42 is formed, which can prevent the leakage of the electrolyte.

[0051] Next, the joint J between the positive terminal 20 and the plurality of current collectors 50 will be described in detail. Figure 3 is a schematic diagram showing the process of joining the positive terminal 20 and the plurality of current collectors 50.

[0052] The positive terminal 20 and the plurality of current collectors 50 are joined using an ultrasonic bonder 2. The ultrasonic bonder 2 includes: an anvil 3 having a support surface 3a for supporting a workpiece; a sonotrode 4 having a pressing surface 4a for pressing the workpiece; and an ultrasonic vibration generator 5 for applying ultrasonic vibration to the sonotrode 4. The sonotrode 4 presses the positive terminal 20 and the plurality of current collectors 50 along a pressing direction D1, and the pressing direction D1 is along the thickness direction of the positive terminal 20. In addition, the sonotrode 4 vibrates along a vibration direction D2 orthogonal to the pressing direction D1.

[0053] Figure 4 is a top view of the support surface 3a of the anvil 3.Figure 5 is the end view of the anvil 3 when observed from the arrow V shown below. The arrow V is along the third straight line L3 described later. Figure 4 As shown in and

[0054] , when observed from the arrow V, the support surface 3a of the anvil 3 extends in a rectangular shape along the first straight line L1 orthogonal to the vibration direction D2 of the sonotrode 4. It should be noted that the top view of the support surface 3a is to observe the support surface 3a along the pressing direction D1. In addition, on the support surface 3a, a plurality of first protrusions T1, a plurality of second protrusions T2, and a plurality of third protrusions T3 are arranged in a state where the support surface 3a is line-symmetric with the first straight line L1 as the axis of symmetry.

[0054] As Figure 4 shown, the support surface 3a of the anvil 3 extends in a rectangular shape along the first straight line L1 orthogonal to the vibration direction D2 of the sonotrode 4 when observed from above. It should be noted that the top view of the support surface 3a is to observe the support surface 3a along the pressing direction D1. In addition, on the support surface 3a, a plurality of first protrusions T1, a plurality of second protrusions T2, and a plurality of third protrusions T3 are arranged in a state where the support surface 3a is line-symmetric with the first straight line L1 as the axis of symmetry.

[0055] The first protrusion T1, the second protrusion T2, and the third protrusion T3 are each in the shape of a frustum of a square pyramid. That is, the upper surface and the lower surface of each of the first protrusion T1, the second protrusion T2, and the third protrusion T3 are planar. It should be noted that the first protrusion T1, the second protrusion T2, and the third protrusion T3 that overlap with the periphery of the support surface 3a in the top view are formed in a shape that is cut off by the periphery of the support surface 3a in the top view. Hereinafter, regarding the shapes of the first protrusion T1, the second protrusion T2, and the third protrusion T3, the shapes in the state where they are not cut off by the periphery of the support surface 3a2 will be described.

[0056] As Figure 5 shown, the lower surfaces of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3 are located on the first plane S1 orthogonal to the pressing direction D1. In addition, the upper surfaces of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3 are located on the second plane S2 parallel to the first plane S1 (i.e., on the same plane). That is, the heights of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3 are equal to each other.

[0057] As Figure 4 shown, the first range A1 in which a plurality of first protrusions T1 are arranged is located at the central portion of the support surface 3a in the direction along the first straight line L1 in the top view. The lower surface and the upper surface of the first protrusion T1 are square-shaped in the top view. In addition, the plurality of first protrusions T1 are arranged adjacent to each other with the diagonal lines parallel to the first straight line L1. Thus, the plurality of first protrusions T1 are arranged in a matrix along the second straight line L2 and the third straight line L3 that intersect the first straight line L1 in the top view.

[0058] When viewed from above, the second straight line L2 and the third straight line L3 are orthogonal to each other, and the angles formed by the second straight line L2 and the third straight line L3 with the first straight line L1 are equal to each other, being 45°. The side of the lower surface of the first protrusion T1 is parallel to one of the second straight line L2 and the third straight line L3.

[0059] In addition, in two adjacent first protrusions T1, the sides of the lower surfaces are in contact with each other. That is, the cross-section between two adjacent first protrusions T1 is V-shaped.

[0060] The second range A2 in which a plurality of second protrusions T2 are arranged is arranged adjacent to the first range A1 on both outer sides of the first range A1 in the direction along the first straight line L1. In addition, the second range A2 is located at a position deviated from the ranges extending along the second straight line L2 and the third straight line L3 from the first range A1 respectively.

[0061] The lower surface and the upper surface of the second protrusion T2 are square-shaped when viewed from above. When viewed from above, the length of the side in the lower surface of the second protrusion T2 is longer than the length of the side in the lower surface of the first protrusion T1 (specifically, 2 times). That is, when viewed from above, the area of the lower surface of the second protrusion T2 is larger than the area of the lower surface of the first protrusion T1 (specifically, 4 times). In addition, when viewed from above, the area of the upper surface of the second protrusion T2 is larger than the area of the upper surface of the first protrusion T1.

[0062] In addition, a plurality of second protrusions T2 are arranged adjacent to each other with the diagonal of the lower surface parallel to the first straight line L1. Thus, a plurality of second protrusions T2 are arranged in a matrix along the second straight line L2 and the third straight line L3 when viewed from above. The side of the lower surface of the second protrusion T2 is parallel to one of the second straight line L2 and the third straight line L3.

[0063] In addition, in two adjacent second protrusions T2, the sides of the lower surfaces are in contact with each other. That is, the cross-section between two adjacent second protrusions T2 is V-shaped. In addition, in an adjacent second protrusion T2 and the first protrusion T1, the vertices of the lower surfaces are in contact with each other. That is, the cross-section between an adjacent second protrusion T2 and the first protrusion T1 is V-shaped.

[0064] A third range A3 configured with a plurality of third protrusions T3 is located within a range extending from the first range A1 along a second straight line L2 and a third straight line L3, respectively. The plurality of third ranges A3 are located between the first range A1 and the second range A2 in the direction along the first straight line L1. The third range A3 is adjacent to the first range A1 in one direction along the second straight line L2 and the third straight line L3. In addition, the plurality of third ranges A3 are adjacent to the second range A2 in one direction along the second straight line L2 and the third straight line L3.

[0065] The lower surface and the upper surface of the third protrusion T3 are rectangular in a top view. In a top view, the area of the upper surface of the third protrusion T3 is larger than the area of the upper surface of the first protrusion T1 and smaller than the area of the upper surface of the second protrusion T2.

[0066] In addition, among the long side and the short side of the lower surface of the third protrusion T3, the length of the long side is equal to the length of one side of the lower surface of the second protrusion T2, and the length of the short side is equal to the length of one side of the lower surface of the first protrusion T1. The plurality of third protrusions T3 are arranged in a matrix along the second straight line L2 and the third straight line L3 in a top view. The side of the lower surface of the third protrusion T3 is parallel to one of the second straight line L2 and the third straight line L3.

[0067] In addition, among two adjacent third protrusions T3, the sides of the lower surfaces are in contact with each other. That is, the cross-section between two adjacent third protrusions T3 is V-shaped.

[0068] In addition, the adjacent third protrusion T3 and the first protrusion T1 are adjacent to each other in one direction along the second straight line L2 and the third straight line L3. Among the adjacent third protrusion T3 and the first protrusion T1, the sides of the lower surfaces are in contact with each other. That is, the cross-section between the adjacent third protrusion T3 and the first protrusion T1 is V-shaped.

[0069] In addition, the adjacent third protrusion T3 and the second protrusion T2 are adjacent to each other in one direction along the second straight line L2 and the third straight line L3. Among the adjacent third protrusion T3 and the second protrusion T2, the sides of the lower surfaces are in contact with each other. That is, the cross-section between the adjacent third protrusion T3 and the second protrusion T2 is V-shaped.

[0070] In addition, the inclination angles of the side surfaces of the first protruding portion T1, the second protruding portion T2, and the third protruding portion T3 are equal to each other. In the support surface 3a having such a shape, simplification of the manufacturing process can be achieved. Specifically, between the first protruding portion T1, the second protruding portion T2, and the third protruding portion T3, a plurality of grooves having a V-shaped cross-section formed by the side surfaces of the first protruding portion T1, the second protruding portion T2, and the third protruding portion T3 are continuous from one side of the support surface 3a to the other side in a direction along one of the second straight line L2 and the third straight line L3. Therefore, by moving a grinding wheel having a corner with a V-shaped cross-section from one side of the support surface 3a to the other side in a direction along the second straight line L2 and the third straight line L3 to grind the support surface 3a, the above-mentioned plurality of first protruding portions T1, plurality of second protruding portions T2, and plurality of third protruding portions T3 can be formed simply.

[0071] Figure 6 is a top view of the pressing surface 4a of the welding head 4. Figure 7 is a side view of the welding head 4. Figure 8 is along Figure 6 a cross-sectional view of the welding head 4 taken along the line VIII-VIII shown. Figure 9 is along Figure 6 a cross-sectional view of the welding head 4 taken along the line IX-IX shown.

[0072] The pressing surface 4a of the welding head 4 has a rectangular shape extending along a fourth straight line L4 orthogonal to the vibration direction D2 in a top view. It should be noted that the top view of the pressing surface 4a is to observe the pressing surface 4a along the pressing direction D1. In a top view, the corners of the pressing surface 4a are chamfered. In a top view, the area of the pressing surface 4a is smaller than the area of the support surface 3a.

[0073] On the pressing surface 4a, a plurality of sixth protruding portions T6 are arranged in a state where the pressing surface 4a is line-symmetric with respect to the fourth straight line L4 as the axis of symmetry. The plurality of sixth protruding portions T6 are arranged in a matrix along a fifth straight line L5 and a sixth straight line L6 that intersect with the fourth straight line L4 in a top view.

[0074] In a top view, the fifth straight line L5 and the sixth straight line L6 are orthogonal to each other, and the angles formed by the fifth straight line L5 and the sixth straight line L6 with the fourth straight line L4 are equal to each other, being 45°. The side of the lower surface of the sixth protruding portion T6 is parallel to one of the fifth straight line L5 and the sixth straight line L6.

[0075] The lower surface of the sixth protruding portion T6 has a square shape and is a shape in which the width becomes smaller toward the protruding end. The sides of the lower surfaces of two adjacent sixth protruding portions T6 are in contact with each other. In addition, as Figure 7 、 8, as shown in FIGS. 9, the lower surfaces of the plurality of sixth protrusions T6 are each located on a third plane S3 orthogonal to the pressing direction D1.

[0076] In addition, as Figure 6 shown, the plurality of sixth protrusions T6 are arranged such that, in a plan view, the diagonal of the lower surface is parallel to the fourth straight line L4. Hereinafter, the sixth protrusion T6 among the plurality of sixth protrusions T6 whose upper surface overlaps with the fourth straight line L4 in a plan view is referred to as a seventh protrusion T7, and the sixth protrusions T6 located on both sides of the seventh protrusion T7 in the vibration direction D2 are referred to as eighth protrusions T8.

[0077] As Figure 7 shown, in a side view orthogonal to the vibration direction D2, the pressing surface 4a has an arc C that passes through the periphery of the pressing surface 4a in the vibration direction D2 and is convex toward the outside of the soldering head 4. The seventh protrusion T7 does not overlap with the arc C in a side view. The seventh protrusion T7 is in the shape of a truncated cone with a quadrilateral (specifically, a square) upper surface and lower surface. As Figure 7 , 8 shown, the upper surface and the side surface of the seventh protrusion T7 are linear in a cross-sectional view.

[0078] On the other hand, the eighth protrusion T8 is arc-shaped along the arc C in a side view. That is, as Figure 8 , 9 shown, the upper surface and the side surface of the eighth protrusion T8 are in the shape along the arc C in a cross-sectional view. Specifically, the eighth protrusion T8 is obtained by cutting off the upper surface side of the same truncated cone shape as the seventh protrusion T7 with a curved surface whose side view is the arc C. Accordingly, the heights H2a and H2b of the eighth protrusion T8 are lower than the height H1 of the seventh protrusion T7.

[0079] In addition, among the plurality of eighth protrusions T8, the closer the eighth protrusion T8 is to the periphery of the pressing surface 4a in the vibration direction D2 (in other words, the farther away from the center in the vibration direction D2), the lower the height. Specifically, Figure 8 the eighth protrusion T8 shown in Figure 9 is closer to the periphery of the pressing surface 4a in the vibration direction D2 than the eighth protrusion T8 shown in Figure 8 , and the height H2b of the eighth protrusion T8 shown in Figure 9 is lower than the height H2a of the eighth protrusion T8 shown in

[0080] In addition, the height H1 of the seventh protrusion T7 is higher than the heights of the first protrusion T1, the second protrusion T2, and the third protrusion T3 of the above-described anvil 3 (that is, the distance between the first plane S1 and the second plane S2).

[0081] Next, a process of joining the positive terminal 20 to the plurality of current collectors 50 (hereinafter referred to as the joining process) will be described. As Figure 3 shown, the positive terminal 20 is placed in a state where the opposite surface of the bent surface 21 in the positive terminal 20 is in contact with the support surface 3a of the anvil 3. In addition, a plurality of current collectors 50 are arranged on the bent surface 21 of the positive terminal 20 in an overlapping state.

[0082] In addition, when viewed from above along the pressing direction D1, the support surface 3a and the pressing surface 4a face each other in an overlapping state. At this time, when viewed from above along the pressing direction D1, the first range A1, the second range A2, and the third range A3 of the support surface 3a respectively overlap with the plurality of sixth protrusions T6 of the pressing surface 4a.

[0083] Next, the plurality of current collectors 50 are pressed by the pressing surface 4a of the welding head 4 along the pressing direction D1. Furthermore, the welding head 4 vibrates along the vibration direction D2, whereby the positive terminal 20 and the plurality of current collectors 50 are integrated by welding to form a joint J. It should be noted that the negative terminal 30 and the plurality of current collectors 50 are also joined in the same manner using the ultrasonic bonder 2 to form a joint J.

[0084] As described above, the welding head 4 extends along the fourth straight line L4 orthogonal to the vibration direction D2. Thus, on both side portions of the welding head 4 in the direction along the fourth straight line L4, the vibration of the welding head 4 in the joining process generates not only the vibration along the vibration direction D2 but also the vibration along the pressing direction D1. Therefore, in the support surface 3a of the anvil 3, compared with the central portion of the support surface 3a in the direction along the first straight line L1 orthogonal to the vibration direction D2, the load acting on the support surface 3a in the joining process is larger on both side portions of the support surface 3a in the direction along the first straight line L1, and the wear of the support surface 3a is likely to be larger.

[0085] Regarding the technical problem related to the wear of the support surface 3a, as described above, a plurality of first protrusions T1 are located at the central portion of the support surface 3a in the direction along the first straight line L1, and a plurality of second protrusions T2 are located at both end portions of the support surface 3a in the direction along the first straight line L1. In addition, when viewed from above, the area of the upper surface of the second protrusion T2 is larger than the area of the upper surface of the first protrusion T1. Therefore, at both end portions of the support surface 3a in the direction along the first straight line L1, the concentration of the load acting on the support surface 3a in the joining process can be suppressed, and thus the wear of the support surface 3a can be suppressed.

[0086] In addition, as described above, the heights of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3 are equal to each other. Therefore, it is possible to suppress the concentration of load acting on the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3. Therefore, it is possible to equalize the wear amounts of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3.

[0087] In this way, it is possible to suppress the wear of the support surface 3a at both end portions of the support surface 3a in the direction along the first straight line L1, and it is possible to equalize the wear amounts of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3. Therefore, it is possible to stabilize the joining state of the plurality of current collectors 50 and the positive electrode terminal 20 at the joint portion J.

[0088] Figure 10 is a diagram showing Figure 4 the wear amount of the support surface 3a of the anvil 3 according to the embodiment of the present disclosure shown and the wear amount of the support surface in the anvil 6 of the comparative example. Figure 10 The vertical axis of represents the average wear amount of each of the protrusions T1, T2, and T3, Figure 10 and the horizontal axis of represents the number of joining times (so-called shot number) of the current collector 50 and the positive electrode terminal 20.

[0089] The entire support surface of the anvil 6 of the comparative example is formed by the first protrusions T1, which is different from the anvil 3 of the above-described embodiment. That is, the first protrusions T1 are arranged over the entire support surface of the anvil 6 of the comparative example.

[0090] As Figure 10 shown, the average wear amount of the support surface 3a in the anvil 3 of the present embodiment is less than the average wear amount of the support surface in the anvil 6 of the comparative example. In addition, the greater the number of joining times, the greater the difference between the average wear amount of the support surface 3a of the anvil 3 of the present embodiment and the average wear amount of the support surface of the anvil 6 of the comparative example. That is, in Figure 10 it is shown that by suppressing the wear of the support surface 3a at both end portions of the support surface 3a in the direction along the first straight line L1 and equalizing the wear amounts of the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3 as described above, it is possible to suppress the average wear amount of the support surface 3a in the anvil 3 of the present embodiment.

[0091] Next, the state of the outer surface of the joint portion J between the positive electrode terminal 20 and the plurality of current collectors 50 will be described in detail.

[0092] Figure 11 is a plan view of the joint portion J between the plurality of current collectors 50 and the positive electrode terminal 20 as viewed from the positive electrode terminal 20 side. Figure 11The top view of the joint J shown is a top view of the joint J observed from the positive terminal 20 side along the thickness direction of the positive terminal 20. The top view observation of the joint J means observing the joint J along the thickness direction of the positive terminal 20.

[0093] The outer surface of the positive terminal 20 in the joint J has a concavo-convex first concavo-convex region R1, and the first concavo-convex region R1 has a plurality of depressions recessed in the thickness direction of the positive terminal 20. Figure 11 The double-dashed line shown indicates the periphery of the first concavo-convex region R1. The first concavo-convex region R1 is formed when the current collector 50 is pressed by the welding head 4 along the pressing direction D1 in a state where the positive terminal 20 is supported on the support surface 3a of the anvil 3.

[0094] The first concavo-convex region R1 extends along the first direction W1. In a state where the joint J is supported on the anvil 3 during joining, the first direction W1 is substantially orthogonal to the pressing direction D1 and the vibration direction D2, respectively. The first concavo-convex region R1 has a first concavo-convex pattern P1, two second concavo-convex patterns P2, and four third concavo-convex patterns P3. Figure 11 The seventh straight line L7, the eighth straight line L8, the ninth straight line L9, and the tenth straight line L10 shown indicate the boundary lines of the first concavo-convex pattern P1, the second concavo-convex pattern P2, and the third concavo-convex pattern P3 (details will be described below).

[0095] The first concavo-convex pattern P1 is located at the center of the first concavo-convex region R1 in the first direction W1. The first concavo-convex pattern P1 is located between the two second concavo-convex patterns P2 in a top view. Specifically, the first concavo-convex pattern P1 is located between the two second concavo-convex patterns P2 in the first direction W1. The first concavo-convex pattern P1 has a plurality of first concave portions U1.

[0096] It should be noted that regarding the first concave portion U1, and the second concave portion U2 and the third concave portion U3 described below, the first concave portion U1, the second concave portion U2, and the third concave portion U3 that overlap with the periphery of the first concavo-convex region R1 in a top view become shapes cut off by the periphery of the first concavo-convex region R1. Hereinafter, regarding the shapes of the first concave portion U1, the second concave portion U2, and the third concave portion U3, the shapes in a state where they are not cut off by the periphery of the first concavo-convex region R1 will be described.

[0097] The plurality of first concave portions U1 are arranged in a matrix along the second direction W2 and the third direction W3 that intersect each other in a top view. In the present embodiment, the second direction W2 and the third direction W3 are orthogonal to each other in a top view. The second direction W2 and the third direction W3 intersect the first direction W1, respectively.

[0098] Figure 12 is shown Figure 11Partial enlarged view of the first concavo-convex region R1 of the first concavo-convex pattern P1 shown. Figure 12 It is the enlarged view of the range represented by the frame XI of the rectangular shape shown by Figure 11 The bottom B1 of the first recess U1 corresponds to the shape of the upper surface of the first protrusion T1 of the support surface 3a. Specifically, the bottom B1 of the first recess U1 is planar and square-shaped when viewed from above. It should be noted that in this specification, planar means a range having a specified surface roughness that is sufficiently smaller than the step difference between the periphery of the bottom B1 of the first recess U1 in the pressing direction D1 and the bottom B1. The sufficiently small specified surface roughness is 1 / 10 or less of the step difference between the periphery of the bottom B1 of the first recess U1 in the pressing direction D1 and the bottom B1. The surface roughness can be measured by measuring and analyzing the three-dimensional shape of the surface of the bottom B1 using a non-contact surface roughness measuring device such as a laser microscope. The non-contact surface roughness measuring device sets the magnification to 200 times and sets the measurement range of a diameter of 0.05 mm near the center of the bottom B1 of the first recess D1 to obtain the surface roughness. For example, when the measured roughness Ry (μm) is 20 (μm) or less, it can be determined that the bottom B1 is planar. It should be noted that the roughness Ry is the maximum height specified by JIS B0601 (1994) and JIS B 0031 (1994). In the second direction W2 and the third direction W3 respectively, the intervals between the bottoms B1 of two adjacent first recesses U1 (specifically, the distances between the center points of the bottoms B1 of the first recesses U1 when viewed from above) are equal to each other.

[0099] Figure 13 It is a cross-sectional view of the joint portion J. As described above, the upper surfaces of the plurality of first protrusions T1 are located on the same plane, and thus the bottoms B1 of the plurality of first recesses U1 are located on the fourth plane S4 (i.e., on the same plane).

[0100] As Figure 11 shown, the second concavo-convex pattern P2 is located adjacent to the first concavo-convex pattern P1 on both outer sides of the first concavo-convex pattern P1 in the first direction W1. In addition, the second concavo-convex pattern P2 is located at a position deviated from the range extending from the first concavo-convex pattern P1 along the second direction W2 and the third direction W3 when viewed from above. The second concavo-convex pattern P2 has a plurality of second recesses U2.

[0101] The plurality of second recesses U2 are arranged along one of the second direction W2 and the third direction W3 when viewed from above. In the present embodiment, the plurality of second recesses U2 are arranged in a matrix along the second direction W2 and the third direction W3 when viewed from above. When viewed from above, the area of the second recess U2 is larger than the area of the first recess U1.

[0102] Figure 14 It showsFigure 11 A partial enlarged view of the first concavo-convex pattern P1, the second concavo-convex pattern P2, and the first concavo-convex region R1 of the third concavo-convex pattern P3 shown. Figure 14 It is composed of Figure 11 An enlarged view of the range represented by the rectangular frame XIV shown. The bottom B2 of the second recess U2 corresponds to the shape of the upper surface of the second protrusion T2 of the support surface 3a. Specifically, the bottom B2 of the second recess U2 is planar and square-shaped when viewed from above. In addition, the area of the bottom B2 of the second recess U2 is larger than the area of the bottom B1 of the first recess U1. Also, in the first direction W1, the length of the bottom B2 of the second recess U2 is longer than the length of the bottom B1 of the first recess U1.

[0103] In the second direction W2 and the third direction W3 respectively, the intervals between the bottoms B2 of two adjacent second recesses U2 (specifically, the distances between the center points of the bottoms B2 of the second recesses U2 when viewed from above) are equal to each other. Also, in the second direction W2 and the third direction W3 respectively, the intervals between the bottoms B2 of two adjacent second recesses U2 are larger than the intervals between the bottoms B1 of two adjacent first recesses U1.

[0104] As Figure 13 shown, the bottoms B2 of the plurality of second recesses U2, like the bottoms B1 of the plurality of first recesses U1, are located on the fourth plane S4 (i.e., on the same plane). As described above, the upper surfaces of the plurality of first protrusions T1 and the upper surfaces of the plurality of second protrusions T2 are located on the same plane, whereby the bottoms B1 of the plurality of first recesses U1 and the bottoms B2 of the plurality of second recesses U2 are located on the same plane.

[0105] As Figure 11 shown, the third concavo-convex pattern P3 is located within the range extending from the first concavo-convex pattern P1 along the second direction W2 and the third direction W3 respectively. The third concavo-convex pattern P3 is located between the first concavo-convex pattern P1 and the second concavo-convex pattern P2 in the first direction W1. The third concavo-convex pattern P3 is adjacent to the first concavo-convex pattern P1 on one side of the second direction W2 and the third direction W3. In addition, the third concavo-convex pattern P3 is adjacent to the second concavo-convex pattern P2 on one side of the second direction W2 and the third direction W3. The third concavo-convex pattern P3 has a plurality of third recesses U3.

[0106] The plurality of third recesses U3 are arranged along at least one of the second direction W2 and the third direction W3 when viewed from above. When viewed from above, the area of the third recess U3 is larger than the area of the first recess U1 and smaller than the area of the second recess U2.

[0107] Figure 14The bottom B3 of the third recess U3 shown corresponds to the shape of the upper surface of the third protrusion T3 of the support surface 3a. Specifically, the bottom B3 of the third recess U3 is planar and rectangular in a top view. In addition, the area of the bottom B3 of the third recess U3 is larger than the area of the bottom B1 of the first recess U1 and smaller than the area of the bottom B2 of the second recess U2.

[0108] The interval between the bottoms B3 of two third recesses U3 adjacent to each other in the second direction W2 (specifically, the distance between the center points of the bottoms B3 of the third recesses U3 in a top view) is different from the interval between the bottoms B3 of two third recesses U3 adjacent to each other in the third direction W3.

[0109] Specifically, with respect to the third concavo-convex pattern P3 adjacent to the first concavo-convex pattern P1 in the second direction W2, the interval between the bottoms B3 of two third recesses U3 adjacent to each other in the second direction W2 is equal to the interval between the bottoms B2 of two second recesses U2 adjacent to each other in the second direction W2 and the third direction W3, and the interval between the bottoms B3 of two third recesses U3 adjacent to each other in the third direction W3 is equal to the interval between the bottoms B1 of two first recesses U1 adjacent to each other in the second direction W2 and the third direction W3.

[0110] In addition, with respect to the third concavo-convex pattern P3 adjacent to the first concavo-convex pattern P1 in the third direction W3, the interval between the bottoms B3 of two third recesses U3 adjacent to each other in the second direction W2 is equal to the interval between the bottoms B1 of two first recesses U1 adjacent to each other in the second direction W2 and the third direction W3, and the interval between the bottoms B3 of two third recesses U3 adjacent to each other in the third direction W3 is equal to the interval between the bottoms B1 of two first recesses U1 adjacent to each other in the second direction W2 and the third direction W3.

[0111] As Figure 13 shown, the bottoms B3 of the plurality of third recesses U3 are located on the fourth plane S4 (i.e., the same plane) in the same manner as the bottoms B1 of the plurality of first recesses U1 and the bottoms B2 of the plurality of second recesses U2. As described above, the upper surfaces of the plurality of first protrusions T1, the upper surfaces of the plurality of second protrusions T2, and the upper surfaces of the plurality of third protrusions T3 are located on the same plane, whereby the bottoms B1 of the plurality of first recesses U1, the bottoms B2 of the plurality of second recesses U2, and the bottoms B3 of the plurality of third recesses U3 are located on the same plane.

[0112] It should be noted that the seventh straight line L7 and the ninth straight line L9 are parallel to the second direction W2. Additionally, the seventh straight line L7 and the ninth straight line L9 pass between the first concave portion U1 and the third concave portion U3 adjacent to each other in the third direction W3, and between the third concave portion U3 and the second concave portion U2. Moreover, the eighth straight line L8 and the tenth straight line L10 are parallel to the third direction W3. Additionally, the eighth straight line L8 and the tenth straight line L10 pass between the first concave portion U1 and the third concave portion U3 adjacent to each other in the second direction W2, and between the third concave portion U3 and the second concave portion U2. That is, the seventh straight line L7, the eighth straight line L8, the ninth straight line L9, and the tenth straight line L10 correspond to the ridge lines between the mutually adjacent first concavo-convex pattern P1, second concavo-convex pattern P2, and third concavo-convex pattern P3.

[0113] Furthermore, the ranges of the first concavo-convex pattern P1, the second concavo-convex pattern P2, and the third concavo-convex pattern P3 can be determined by depicting the peripheries of the first concavo-convex region R1, the seventh straight line L7, the eighth straight line L8, the ninth straight line L9, and the tenth straight line L10 on an image of the outer surface of the joint J with a magnification of, for example, 100 times. Additionally, regarding the distances between the center points of the bottoms B1 of the above-mentioned first concave portion U1, the distances between the center points of the bottoms B2 of the second concave portion U2, the distances between the center points of the bottoms B3 of the third concave portion U3, the area of the first concave portion U1, the area of the second concave portion U2, the area of the third concave portion U3, the area of the bottom B1 of the first concave portion U1, the area of the bottom B2 of the second concave portion U2, and the area of the bottom B3 of the third concave portion U3, they can also be measured using an image of the outer surface of the joint J with a magnification of, for example, 100 times.

[0114] As described above, in the bonding process, on both sides of the bonding head 4 in the first direction W1 that is orthogonal to the vibration direction D2 in the same way as the first straight line L1, the vibration of the bonding head 4 in the bonding process generates not only vibration along the vibration direction D2 but also vibration along the pressing direction D1. Therefore, compared with the central portion of the first concavo-convex region R1 in the first direction W1, the load acting on the first concavo-convex region R1 on both sides in the first direction W1 is larger in the bonding process, and cracks may occur in the joint J.

[0115] Regarding the technical problem related to the cracking of the joint J, as described above, a plurality of first concave portions U1 are located in the central portion of the first concavo-convex region R1 in the first direction W1, and a plurality of second concave portions U2 are located at both ends of the first concavo-convex region R1 in the first direction W1. Additionally, when viewed from above, the area of the second concave portion U2 is larger than the area of the first concave portion U1. Therefore, at both ends of the first concavo-convex region R1 in the first direction W1, the concentration of the load acting on the joint J in the bonding process can be suppressed.

[0116] In addition, in the case where a plurality of second recesses U2 are located at both end portions of the first concavo-convex region R1 in the first direction W1, by making the area of the second recess U2 larger than the area of the first recess U1, local compression of the joint portion J at both end portions of the first concavo-convex region R1 can be suppressed. Therefore, generation of cracks in the joint portion J can be suppressed, and stabilization of the joint state of the plurality of current collectors 50 and the positive terminal 20 can be achieved at the joint portion J.

[0117] In addition, as described above, the bottom surfaces B1 of the plurality of first recesses U1, the bottom surfaces B2 of the plurality of second recesses U2, and the bottom surfaces B3 of the plurality of third recesses U3 are located on the same plane. Therefore, compared with the case where the bottom surfaces B1 of the plurality of first recesses U1, the bottom surfaces B2 of the plurality of second recesses U2, and the bottom surfaces B3 of the plurality of third recesses U3 are located on different planes from each other, local compression of the joint portion J can be suppressed. Therefore, generation of cracks in the joint portion J can be suppressed, and stabilization of the joint state of the plurality of current collectors 50 and the positive terminal 20 can be achieved at the joint portion J.

[0118] Figure 15 is a top view of the joint portion J of the plurality of current collectors 50 and the positive terminal 20 as viewed from the current collector 50 side. In other words, Figure 15 the top view of the joint portion J shown is a top view showing the joint portion J as viewed from the current collector 50 side along the thickness direction of the positive terminal 20.

[0119] The outer surface of the current collector 50 in the joint portion J has a concavo-convex second concavo-convex region R2, and the second concavo-convex region R2 has a plurality of depressions that are recessed in the thickness direction of the positive terminal 20. The second concavo-convex region R2 is formed by pressing the current collector 50 along the pressing direction D1 by the welding head 4 in a state where the positive terminal 20 is supported on the support surface 3a of the anvil 3. The second concavo-convex region R2 extends along the first direction W1. The second concavo-convex region R2 has a plurality of sixth recesses U6.

[0120] Figure 16 is Figure 15 an enlarged view of the second concavo-convex region R2 shown. Figure 17 is along Figure 16 a cross-sectional view of the joint portion J along the line XVII-XVII shown. Figure 18 is along Figure 16 a cross-sectional view of the joint portion J along the line XVIII-XVIII shown.

[0121] The plurality of sixth recesses U6 and the sixth protrusion T6 (seventh protrusion T7 and eighth protrusion T8 of the pressing surface 4a: refer to Figure 7 、 8, corresponding to the shape of (9). Specifically, the shape of the sixth concave portion U6 located at the central portion of the second concavo-convex region R2 in the vibration direction D2 corresponds to the shape of the seventh protruding portion T7 of the welding head 4. In addition, the shape of the sixth concave portion U6 located on both side portions of the second concavo-convex region R2 in the vibration direction D2 corresponds to the shape of the eighth protruding portion T8. As Figure 16 shown, a plurality of sixth concave portions U6 are arranged in a matrix along the second direction W2 and the third direction W3.

[0122] As described above, the height of the eighth protruding portion T8 of the welding head 4 is lower than the height of the seventh protruding portion T7. In addition, in the vibration direction D2, as approaching the periphery of the second concavo-convex region R2, the depth of the sixth concave portion U6 becomes shallower. Therefore, as Figure 17 , 18 shown, in the case where the seventh straight line L7 connecting the peripheries E of the second concavo-convex regions R2 located on both side portions in the vibration direction D2 is used as a reference, the depth of the bottom B6a of the sixth concave portion U6 located at the central portion in the vibration direction D2 among the plurality of sixth concave portions U6 is the deepest. In addition, in the vibration direction D2, as approaching the periphery E of the second concavo-convex region R2, the depth of the bottom of the sixth concave portion U6 becomes shallower.

[0123] Specifically, among the plurality of sixth concave portions U6 shown in Figure 17 , 18 shown, the bottom B6a of the sixth concave portion U6 located at the central portion of the vibration direction D2 shown in Figure 17 , the bottom B6b of the sixth concave portion U6 located on the outer side than the center in the vibration direction D2 shown in Figure 18 , and the bottom B6c of the sixth concave portion U6 located on the outer side than the center in the vibration direction D2 shown in Figure 17 shown are successively closer to the periphery E of the second concavo-convex region R2 in the vibration direction D2. In addition, the depth of the bottom B6a, the depth of the bottom B6b, and the depth of the bottom B6c become shallower in sequence.

[0124] Accordingly, in the vibration direction D2, as approaching the periphery E of the second concavo-convex region R2, the compression rate of the joint portion J of the bottom of the sixth concave portion U6 becomes lower. That is, in the bonding process, breakage of the current collector 50 at the peripheral portion of the second concavo-convex region R2 in the vibration direction D2 is suppressed. Therefore, the bonding state of the plurality of current collectors 50 to the positive electrode terminal 20 can be stabilized.

[0125] In addition, as described above, the eighth protruding portion T8 of the welding head 4 is in an arc shape along the arc C passing through the periphery of the pressing surface 4a in the vibration direction D2 in a cross-sectional view. Therefore, as Figure 17 , 18As shown, on the outer side of the center in the vibration direction D2, in the sixth concave portion U6 on the periphery E of the second concavo-convex region R2, the outer surface connecting the periphery E and the bottom of the second concavo-convex region R2 is an arc-shaped cross-section substantially along the arc C.

[0126] Accordingly, in the vibration direction D2, in the sixth concave portion U6 on the periphery of the second concavo-convex region R2, the compression rate of the joint J decreases from the bottom toward the periphery E of the second concavo-convex region R2. That is, in the joining process, breakage of the current collector 50 at the periphery of the second concavo-convex region R2 in the vibration direction D2 is suppressed. Therefore, the joining state of the plurality of current collectors 50 to the positive terminal 20 can be stabilized.

[0127] In addition, as described above, the upper surface of the seventh protruding portion T7 of the soldering head 4 is flat. Therefore, the bottom B6a of the sixth concave portion U6 located at the center of the vibration direction D2 shown is flat. Figure 16 As shown.

[0128] Accordingly, at the portion of the joint J with a high compression rate at the center of the vibration direction D2, it is compressed into a flat shape, thereby suppressing breakage of the current collector 50. Therefore, the joining state of the plurality of current collectors 50 to the positive terminal 20 can be stabilized.

[0129] In addition, as described above, the height H1 of the seventh protruding portion T7 corresponding to the second concavo-convex region R2 is higher than the heights of the first protruding portion T1, the second protruding portion T2, and the third protruding portion T3 corresponding to the first concavo-convex region R1, respectively. Accordingly, as Figure 13 shown. The depth De1 corresponding to the depth of the first concave portion U1, the depth of the second concave portion U2, and the depth of the third concave portion U3 of the first concavo-convex region R1 is shallower than the depth De2 corresponding to the deepest portion (i.e., the bottom B6a) of the sixth concave portion U6 of the second concavo-convex region R2. That is, the depth of the first concavo-convex region R1 is shallower than the depth of the second concavo-convex region R2. Accordingly, the compression rate of the joint J on the positive terminal 20 side is lower than the compression rate of the joint J on the current collector 50 side. Therefore, generation of cracks at the joint J on the positive terminal 20 side can be suppressed, and stabilization of the joining state of the plurality of current collectors 50 to the positive terminal 20 can be achieved at the joint J.

[0130] It should be noted that the joining of the plurality of current collectors 50 to the negative terminal 30 is carried out in the same manner as the joining of the plurality of current collectors 50 to the positive terminal 20. That is, in the joint J of the plurality of current collectors 50 to the negative terminal 30, the first concavo-convex region R1 and the second concavo-convex region R2 are formed in the same manner as in the joint J of the plurality of current collectors 50 to the positive terminal 20. Therefore, the joint J of the plurality of current collectors 50 to the negative terminal 30 can achieve stabilization of the joining state of the plurality of current collectors 50 to the negative terminal 30 in the same manner as the above-described joint J of the plurality of current collectors 50 to the positive terminal 20.

[0131] Next, regarding the joint portion J related to the first modification of the embodiment of the present disclosure, the differences from the joint portion J related to the above-described embodiment will be mainly described.

[0132] Figure 19 It is a top view of the anvil 3 used in the joining process related to the first modification of the embodiment of the present disclosure. Figure 20 It is from Figure 19 The end view of the anvil 3 when viewed from the arrow XX shown. The arrow XX is along the third direction W3.

[0133] On the support surface 3a1 of the anvil 3 related to this first modification, the plurality of first protrusions T1 are in the shape of a quadrangular pyramid. In addition, the plurality of third protrusions T3 are triangular in cross-section with a quadrilateral lower surface. It should be noted that the plurality of second protrusions T2 are in the shape of a frustum of a quadrangular pyramid, the same as the second protrusion T2 in the above-described embodiment.

[0134] By performing the joining process using such an anvil 3, the bottom B1 of the first concave portion U1, the bottom B2 of the second concave portion U2, and the bottom B3 of the third concave portion U3 of the first concavo-convex region R1 of the joint portion J have the following shapes. That is, the cross-section of the bottom B1 of the first concave portion U1 corresponding to the shape of the first protrusion T1 is V-shaped. The cross-section of the bottom B3 of the third concave portion U3 corresponding to the shape of the third protrusion T3 is V-shaped. It should be noted that the bottom B2 of the second concave portion U2 corresponding to the shape of the second protrusion T2 is planar and square-shaped when viewed from above, the same as the bottom B2 of the second concave portion U2 in the above-described embodiment.

[0135] Next, regarding the joint portion J related to the second modification of the embodiment of the present disclosure, the differences from the joint portion J related to the first modification of the above-described embodiment will be mainly described. Figure 21 It is a top view of the anvil 3 used in the joining process related to the second modification of the embodiment of the present disclosure.

[0136] The support surface 3a2 of the anvil 3 related to this second modification has, in addition to the plurality of first protrusions T1, the plurality of second protrusions T2, and the plurality of third protrusions T3, a plurality of fourth protrusions T4 and a plurality of fifth protrusions T5. It should be noted that the fourth protrusions T4 and the fifth protrusions T5 that overlap with the periphery of the support surface 3a2 when viewed from above are formed in a shape that is cut off by the periphery of the support surface 3a2 when viewed from above. Hereinafter, regarding the shapes of the fourth protrusions T4 and the fifth protrusions T5, the shapes in the state where they are not cut off by the periphery of the support surface 3a2 will be described.

[0137] A fourth range A4 configured with a plurality of fourth protrusions T4 is disposed adjacent to the two second ranges A2 on both outer sides of the two second ranges A2 in the direction along the first straight line L1. In addition, the fourth range A4 is located at a position deviated from the directions extending along the second straight line L2 and the third straight line L3 from the second range A2, respectively.

[0138] The plurality of fourth protrusions T4 are in the shape of a frustum of a square pyramid. That is, the upper surface and the lower surface of the fourth protrusion T4 are planar. The lower surface and the upper surface of the plurality of fourth protrusions T4 are square-shaped when viewed from above. When viewed from above, the length of the side in the lower surface of the fourth protrusion T4 is longer (specifically, twice) than the length of the side in the lower surface of the second protrusion T2. That is, when viewed from above, the area of the lower surface of the fourth protrusion T4 is larger (specifically, four times) than the area of the lower surface of the second protrusion T2. In addition, when viewed from above, the area of the upper surface of the fourth protrusion T4 is larger than the area of the upper surface of the second protrusion T2.

[0139] In addition, the plurality of fourth protrusions T4 are disposed adjacent to each other with the diagonals of the lower surfaces parallel to the first straight line L1. Thus, the plurality of fourth protrusions T4 are arranged in a matrix along the second straight line L2 and the third straight line L3 when viewed from above. The sides of the lower surface of the plurality of fourth protrusions T4 are parallel to one of the second straight line L2 and the third straight line L3.

[0140] In addition, in two adjacent fourth protrusions T4, the sides of the lower surfaces are in contact with each other. That is, the cross-section between two adjacent second protrusions T2 is V-shaped. In addition, in an adjacent fourth protrusion T4 and second protrusion T2, the vertices of the lower surfaces are in contact with each other. That is, the cross-section between the adjacent fourth protrusion T4 and second protrusion T2 is V-shaped.

[0141] A fifth range A5 configured with a plurality of fifth protrusions T5 is adjacent to the second range A2 in the directions along the second straight line L2 and the third straight line L3, respectively. In addition, the fifth range A5 is adjacent to the fourth range A4 in the directions along the second straight line L2 and the third straight line L3, respectively.

[0142] The plurality of fifth protrusions T5 are triangular in cross-section with the lower surface formed in a quadrilateral shape. The lower surface and the upper surface of the fifth protrusion T5 are rectangular when viewed from above. When viewed from above, the area of the upper surface of the fifth protrusion T5 is larger than the area of the upper surface of the second protrusion T2 and smaller than the area of the upper surface of the fourth protrusion T4.

[0143] In addition, among the long side and the short side on the lower surface of the fifth protrusion T5, the length of the long side is equal to the length of one side of the lower surface of the fourth protrusion T4, and the length of the short side is equal to the length of one side of the lower surface of the second protrusion T2. The plurality of fifth protrusions T5 are arranged along one of the second straight line L2 and the third straight line L3 in a top view. The sides of the lower surfaces of the plurality of third protrusions T3 are parallel to one of the second straight line L2 and the third straight line L3. It should be noted that the plurality of fifth protrusions T5 may also be arranged in a matrix along the second straight line L2 and the third straight line L3 in a top view.

[0144] In addition, among two adjacent fifth protrusions T5, the sides of the lower surfaces are in contact with each other. That is, the cross section between two adjacent fifth protrusions T5 is in a V shape.

[0145] In addition, adjacent fifth protrusions T5 and fifth protrusions T5 are adjacent to each other in the direction along one of the second straight line L2 and the third straight line L3, and among the adjacent fifth protrusions T5 and fifth protrusions T5, the sides of the lower surfaces are in contact with each other. That is, the cross section between the adjacent fifth protrusions T5 and fifth protrusions T5 is in a V shape.

[0146] In addition, adjacent fifth protrusions T5 and fourth protrusions T4 are adjacent to each other in the direction along one of the second straight line L2 and the third straight line L3, and among the adjacent fifth protrusions T5 and fourth protrusions T4, the sides of the lower surfaces are in contact with each other. That is, the cross section between the adjacent fifth protrusions T5 and fourth protrusions T4 is in a V shape.

[0147] In addition, the inclination angles of the side surfaces of the first protrusion T1, the second protrusion T2, the third protrusion T3, the fourth protrusion T4, and the fifth protrusion T5 are equal to each other. Therefore, in the support surface 3a2 having such a shape, simplification of the manufacturing process can be achieved. Specifically, the groove having a V-shaped cross section located between the first protrusion T1, the second protrusion T2, the third protrusion T3, the fourth protrusion T4, and the fifth protrusion T5 is continuous from one side of the support surface 3a2 to the other side in the direction along the second straight line L2 and the third straight line L3. Therefore, by grinding the support surface 3a2 by moving a grinding wheel having a V-shaped corner in the cross section in the direction along the second straight line L2 and the third straight line L3 from one side of the support surface 3a2 to the other side, the above-mentioned number of first protrusions T1, a plurality of second protrusions T2, a plurality of third protrusions T3, a plurality of fourth protrusions T4, and a plurality of fifth protrusions T5 can be easily formed.

[0148] By performing the joining process using such an anvil 3, in addition to the above-described first concavo-convex pattern P1, second concavo-convex pattern P2, and third concavo-convex pattern P3, the first concavo-convex region R1 of the joint portion J of this second modification further has two fourth concavo-convex patterns (not shown) and four fifth concavo-convex patterns (not shown).

[0149] The fourth concavo-convex pattern is located on both outer sides of the two second concavo-convex patterns P2 adjacent to the first concavo-convex pattern P1 in the first direction W1. In other words, the two second concavo-convex patterns P2 are located between the two fourth concavo-convex patterns in the first direction W1. Further, the fourth concavo-convex pattern is located at a position deviated from the range extending from the second concavo-convex pattern P2 along the second direction W2 and the third direction W3 in a plan view. The fourth concavo-convex pattern has a plurality of fourth concave portions (not shown).

[0150] The plurality of fourth concave portions are arranged along one of the second direction W2 and the third direction W3 in a plan view. It should be noted that the plurality of fourth concave portions may also be arranged in a matrix along the second direction W2 and the third direction W3 in a plan view. In a plan view, the area of the fourth concave portion is larger than the area of the second concave portion U2.

[0151] Further, the bottom of the fourth concave portion corresponds to the shape of the upper surface of the fourth protruding portion T4 of the support surface 3a2. Specifically, the bottom of the fourth concave portion is planar and square-shaped in a plan view. In addition, the area of the bottom of the fourth concave portion is larger than the area of the bottom of the fourth concave portion.

[0152] In the second direction W2 and the third direction W3 respectively, the intervals between the bottoms of two adjacent fourth concave portions (specifically, the distances between the centers of the bottoms of the fourth concave portions in a plan view) are equal to each other. Further, in the second direction W2 and the third direction W3 respectively, the intervals between the bottoms of two adjacent fourth concave portions are larger than the intervals between the bottoms B2 of two adjacent second concave portions U2.

[0153] The bottoms of the plurality of fourth concave portions are located on the fourth plane S4 (see Figure 13 ). Therefore, the bottoms B1 of the plurality of first concave portions U1, the bottoms B2 of the plurality of second concave portions U2, the bottoms B3 of the plurality of third concave portions U3, and the bottoms of the plurality of fourth concave portions are located on the same plane.

[0154] The fifth concavo-convex pattern is located within the range extending from the second concavo-convex pattern P2 along the second direction W2 and the third direction W3 respectively. The fifth concavo-convex pattern is located between the second concavo-convex pattern P2 and the fourth concavo-convex pattern in the first direction W1. The fifth concavo-convex pattern is adjacent to the second concavo-convex pattern P2 on one of the second direction W2 and the third direction W3. Further, the fifth concavo-convex pattern is adjacent to the fourth concavo-convex pattern on one of the second direction W2 and the third direction W3. The fifth concavo-convex pattern has a plurality of fifth concave portions (not shown).

[0155] A plurality of fifth recesses are arranged along at least one of a second direction W2 and a third direction W3 in a plan view. In the plan view, the area of the fifth recess is larger than the area of the second recess U2 and smaller than the area of the fourth recess.

[0156] The bottom of the fifth recess corresponds to the shape of the upper surface of the fifth protrusion T5 of the support surface 3a. Specifically, the bottom of the fifth recess is planar and rectangular in a plan view. In addition, the area of the bottom of the fifth recess is larger than the area of the bottom B2 of the second recess U2 and smaller than the area of the bottom of the fourth recess.

[0157] The interval between the bottoms of two adjacent fifth recesses in the second direction W2 (specifically, the distance between the center points of the bottoms of the fifth recesses in a plan view) is different from the interval between the bottoms of two adjacent fifth recesses in the third direction W3.

[0158] Specifically, with respect to the fifth concavo-convex pattern adjacent to the second concavo-convex pattern P2 in the second direction W2, the interval between the bottoms of two adjacent fifth recesses in the second direction W2 is equal to the interval between the bottoms of two adjacent fourth recesses in the second direction W2 and the third direction W3, and the interval between the bottoms of two adjacent fifth recesses in the third direction W3 is equal to the interval between the bottoms B2 of two adjacent second recesses U2 in the second direction W2 and the third direction W3.

[0159] In addition, with respect to the fifth concavo-convex pattern adjacent to the second concavo-convex pattern P2 in the third direction W3, the interval between the bottoms of two adjacent fifth recesses in the third direction W3 is equal to the interval between the bottoms of two adjacent fourth recesses in the second direction W2 and the third direction W3, and the interval between the bottoms of two adjacent fifth recesses in the second direction W2 is equal to the interval between the bottoms B2 of two adjacent second recesses U2 in the second direction W2 and the third direction W3.

[0160] The bottoms B3 of the plurality of third recesses U3 are located on the fourth plane S4 (see Figure 13 ). Therefore, the bottoms B1 of the plurality of first recesses U1, the bottoms B2 of the plurality of second recesses U2, the bottoms B3 of the plurality of third recesses U3, the bottoms of the plurality of fourth recesses, and the bottoms of the plurality of fifth recesses are located on the same plane.

[0161] Next, regarding the joint portion J according to the third modification of the embodiment of the present disclosure, the differences from the joint portion J according to the above-described embodiment will be mainly described. Figure 22 It is a plan view of the anvil 3 used in the joining process according to the third modification of the embodiment of the present disclosure.

[0162] On the support surface 3a3 of the anvil 3 in this third modified example, the first protruding portion T1, the second protruding portion T2, and the third protruding portion T3 are each a frustum of a quadrangular pyramid having a rectangular shape on the lower and upper surfaces. Further, since the lower surface of the first protruding portion T1 has a rectangular shape, the shape of the third protruding portion T3 located in the third range A3 adjacent to the first range A1 in the second direction W2 is different from the shape of the third protruding portion T3 located in the third range A3 adjacent to the first range A1 in the third direction W3.

[0163] By performing the joining process using such an anvil 3, the bottoms B1 of the first concave portions U1, the bottoms B2 of the second concave portions U2, and the bottoms B3 of the third concave portions U3 of the first concavo-convex region R1 of the joint J have the following shapes. That is, the bottom B1 of the first concave portion U1 corresponding to the shape of the first protruding portion T1, the bottom B2 of the second concave portion U2 corresponding to the shape of the second protruding portion T2, and the bottom B3 of the third concave portion U3 corresponding to the shape of the third protruding portion T3 are each planar and rectangular in a plan view.

[0164] Next, regarding the joint J according to the fourth modified example of the embodiment of the present disclosure, the differences from the joint J according to the above-described embodiment will be mainly described. Figure 23 It is a plan view of the anvil 3 used in the joining process according to the fourth modified example of the embodiment of the present disclosure.

[0165] On the support surface 3a4 of the anvil 3 according to this fourth modified example, in a plan view, the second straight line L2 and the third straight line L3 intersect non-perpendicularly. The angle formed by the second straight line L2 and the first straight line L1 is equal to the angle formed by the third straight line L3 and the first straight line L1, for example, 60°. As a result, the first protruding portion T1 and the second protruding portion T2 are each a frustum of a quadrangular pyramid having a rhombus shape on the lower and upper surfaces. Further, the third protruding portion T3 is a frustum of a quadrangular pyramid having a parallelogram shape on the lower and upper surfaces.

[0166] By performing the joining process using such an anvil 3, the second direction W2 and the third direction W3 intersect non-perpendicularly in a plan view.

[0167] In addition, the bottoms B1 of the first concave portions U1, the bottoms B2 of the second concave portions U2, and the bottoms B3 of the third concave portions U3 of the first concavo-convex region R1 of the joint J have the following shapes. That is, the bottom B1 of the first concave portion U1 corresponding to the shape of the first protruding portion T1 and the bottom B2 of the second concave portion U2 corresponding to the shape of the second protruding portion T2 are each planar and rhombus-shaped in a plan view. Further, the bottoms B3 of the third concave portions U3 corresponding to the shape of the third protruding portion T3 are each planar and parallelogram-shaped in a plan view.

[0168] Next, regarding the joint portion J related to the fifth modification of the embodiment of the present disclosure, the differences from the joint portion J related to the above-described embodiment will be mainly described. Figure 24 It is a top view of the anvil 3 used in the joining process related to the fifth modification of the embodiment of the present disclosure.

[0169] On the support surface 3a5 of the anvil 3 related to this fifth modification, in a top view, the second straight line L2 and the third straight line L3 intersect non - orthogonally with each other. In addition, the angle formed by the second straight line L2 and the first straight line L1 is different from the angle formed by the third straight line L3 and the first straight line L1. The angle formed by the second straight line L2 and the first straight line L1 is, for example, 45°, and the angle formed by the third straight line L3 and the first straight line L1 is, for example, 60°. Thus, the first protrusion T1, the second protrusion T2, and the third protrusion T3 are each a frustum of a quadrangular pyramid having a parallelogram - shaped lower surface and upper surface.

[0170] In addition, since the lengths of two adjacent sides on the lower surface of the first protrusion T1 are different, the shape of the third protrusion T3 in the third range A3 adjacent to the first range A1 in the second direction W2 is different from the shape of the third protrusion T3 in the third range A3 adjacent to the first range A1 in the third direction W3.

[0171] By performing the joining process using such an anvil 3, the second direction W2 and the third direction W3 intersect non - orthogonally with each other in a top view. In addition, the angle formed by the second direction W2 and the first direction W1 is different from the angle formed by the third direction W3 and the first direction W1.

[0172] In addition, the bottoms B1 of the first recess U1, the bottoms B2 of the second recess U2, and the bottoms B3 of the third recess U3 of the first concavo - convex region R1 of the joint portion J have the following shapes. That is, the bottom B1 of the first recess U1 corresponding to the shape of the first protrusion T1, the bottom B2 of the second recess U2 corresponding to the shape of the second protrusion T2, and the bottom B3 of the third recess U3 corresponding to the shape of the third protrusion T3 are each planar and parallelogram - shaped in a top view.

[0173] Next, the differences between the joint portion J related to the sixth modification of the embodiment of the present disclosure and the joint portion J related to the first modification of the above - described embodiment will be mainly described. Figure 25 It is a top view of the anvil 3 used in the joining process related to the sixth modification of the embodiment of the present disclosure.

[0174] The support surface 3a6 of the anvil 3 related to this sixth modification has two first ranges A1, three second ranges A2, and eight third ranges A3.

[0175] Two first ranges A1 are arranged in a state of being separated from each other in the direction along the first straight line L1. Three second ranges A2 are arranged between the two first ranges A1 in the direction along the first straight line L1, and are arranged on both outer sides of the two first ranges A1 in the direction along the first straight line L1. The third range A3 is located between the first range A1 and the second range A2 in the direction along the first straight line L1. The third range A3 is adjacent to the first range A1 in the direction along one of the second straight line L2 and the third straight line L3. In addition, the third range A3 is adjacent to the second range A2 in the direction along one of the second straight line L2 and the third straight line L3.

[0176] Figure 26 It is a side view of the anvil 3 and the sonotrode 4 according to the sixth modification of the embodiment of the present disclosure. The sonotrode 4 of this sixth modification has two pressing surfaces 4a. In the joining process, the two pressing surfaces 4a respectively overlap with one first range A1, two second ranges A2 adjacent to the one first range A1, and four third ranges A3 adjacent to the one first range A1 in a top view.

[0177] By performing the joining process using such an anvil 3 and sonotrode 4, two first concavo-convex regions R1 as shown in Figure 11 are formed on the outer surface of the positive electrode terminal 20 of the joint J, and two second concavo-convex regions R2 are formed on the outer surface of the current collector 50 of the joint J.

[0178] Next, regarding the joint J according to the seventh modification of the embodiment of the present disclosure, the differences from the joint J according to the above-described embodiment will be mainly described. Figure 27 It is a top view of the anvil 3 used in the joining process according to the seventh modification of the embodiment of the present disclosure.

[0179] The support surface 3a7 of the anvil 3 according to this seventh modification does not have the third range A3. The second range A2 is located on both outer sides of the first range A1 adjacent to the first range A1 in the direction along the first straight line L1.

[0180] The plurality of V-shaped grooves in cross-section between the first protrusion T1 and the second protrusion T2 of this seventh modification include grooves G1 ( Figure 27 the grooves shown by the dotted lines in ) that are discontinuous from one side to the other side of the support surface 3a in the direction along the second straight line L2 and the third straight line L3. In this case, even if a grinding wheel having a V-shaped corner in cross-section is moved from one side of the support surface 3a to the other side in the direction along the second straight line L2 and the third straight line L3, the groove G1 cannot be formed, and the processing process of the support surface 3a is increased compared with the above-described embodiment.

[0181] By performing the joining process using such an anvil 3, the first concavo-convex region R1 does not have the third concavo-convex pattern P3. The second concavo-convex pattern P2 is located adjacent to the first concavo-convex pattern P1 on both outer sides of the first concavo-convex pattern P1 in the first direction W1.

[0182] Next, the differences between the joint J according to the eighth modification of the embodiment of the present disclosure and the joint J according to the seventh modification of the above-described embodiment will be mainly described. Figure 28 It is a plan view of the anvil 3 used in the joining process according to the eighth modification of the embodiment of the present disclosure.

[0183] In the anvil 3 according to this eighth modification, the first straight line L1 and the second straight line L2 of the support surface 3a8 overlap when viewed from above. The second range A2 is located adjacent to the first range A1 on both outer sides of the first range A1 in the direction along the first straight line L1, similarly to the above-described seventh modification.

[0184] The plurality of V-shaped grooves in cross section between the first protrusion T1 and the second protrusion T2 in this eighth modification include grooves G2 (indicated by a dashed line in Figure 28 ) that are located closer to the inside than the periphery of the support surface 3a in the direction along the second straight line L2. In this case, it is difficult to form the groove G2 using a grinding wheel having a V-shaped corner in cross section, and the machining direction of the support surface 3a becomes complicated compared to the above-described embodiment. This groove is formed, for example, by electrical discharge machining or the like.

[0185] By performing the joining process using such an anvil 3, the first concavo-convex region R1 does not have the third concavo-convex pattern P3. Further, the second direction W2 is the same direction as the first direction W1. In the first direction W1, it is located adjacent to the first concavo-convex pattern P1 on both outer sides of the first concavo-convex pattern P1.

[0186] Similar to the joint J of the above-described embodiment, the joint J of each of the above-described modifications can achieve stabilization of the joining state between the plurality of current collectors 50 and the positive electrode terminal 20, and stabilization of the joining state between the plurality of current collectors 50 and the negative electrode terminal 30.

[0187] It should be noted that the above-described embodiment is for facilitating understanding of the present disclosure, rather than for limiting the interpretation of the present disclosure. The present disclosure can be changed / improved without departing from its gist, and its equivalents are also included in the present disclosure.

[0188] For example, the laminate 10 may also be a wound type. Further, the laminate 10 may also constitute an all-solid-state battery. In this case, the laminate 10 has a positive electrode and a negative electrode, and a solid electrolyte is housed in the housing portion 41.

[0189] In addition, the support surface 3a is of course not limited to a rectangular shape when viewed from above. For example, it may also be a square shape or a circular shape when viewed from above.

[0190] In addition, the plurality of first protruding portions T1, the plurality of second protruding portions T2, the plurality of third protruding portions T3, the plurality of fourth protruding portions T4, and the plurality of fifth protruding portions T5 may also be arranged in a state where their lower surfaces are separated from each other.

[0191] In addition, the plurality of sixth protruding portions T6 on the pressing surface 4a may not have the eighth protruding portion T8, but may be constituted by the seventh protruding portion T7. In this case, the bottoms of the plurality of sixth concave portions U6 in the second concavo-convex region R2 correspond to the shape of the seventh protruding portion T7 and are located on the same plane.

[0192] In addition, the first concavo-convex region R1 and the second concavo-convex region R2 may not extend along the first direction W1, and the lengths in two directions orthogonal to each other when viewed from above are equal. For example, they may also be a square shape, a circular shape, etc. In this case, the pressing surface 4a of the welding head 4 is, for example, a square shape, a circular shape, etc. when viewed from above.

[0193] It should be noted that the present disclosure may also be a combination of the following configurations. (1)

[0195] A secondary battery, comprising:

[0196] A laminate in which a plurality of electrodes are laminated;

[0197] A plurality of current collectors electrically connected to the plurality of electrodes; and

[0198] Terminals joined to the plurality of current collectors,

[0199] The outer surface of the terminal in the joint portion of the plurality of current collectors and the terminal has a concavo-convex first concavo-convex region,

[0200] The first concavo-convex region has:

[0201] A first concavo-convex pattern having a plurality of first concave portions; and

[0202] Two second concavo-convex patterns having second concave portions with an area larger than that of the first concave portions on the outer surface of the terminal when viewed from above,

[0203] The first concavo-convex pattern is located between the two second concavo-convex patterns when viewed from above. (2)

[0205] The secondary battery according to (1),

[0206] The first concavo-convex region extends along a first direction when viewed from above,

[0207] The first concavo-convex pattern is located between the two second concavo-convex patterns in the first direction. (3)

[0209] The secondary battery according to (1) or (2),

[0210] A plurality of the first concave portions are arranged in a matrix along a second direction and a third direction that intersect each other under the top view. (4)

[0212] The secondary battery according to (3),

[0213] A plurality of the second concave portions are arranged along one of the second direction and the third direction under the top view. (5)

[0215] The secondary battery according to (3) or (4),

[0216] The first concavo-convex region further has a third concavo-convex pattern, and the third concavo-convex pattern has a plurality of third concave portions whose areas are larger than those of the first concave portions and smaller than those of the second concave portions under the top view,

[0217] The third concavo-convex pattern is adjacent to the first concavo-convex pattern along one of the second direction and the third direction,

[0218] The second concavo-convex pattern is located at a position deviating from the range extending from the first concavo-convex pattern along the second direction and the third direction under the top view. (6)

[0220] The secondary battery according to any one of (1) to (5),

[0221] The outer surface of the current collector in the joint portion has a concavo-convex second concavo-convex region,

[0222] The depth of the first concavo-convex region is shallower than the depth of the second concavo-convex region. (7)

[0224] The secondary battery according to any one of (1) to (6),

[0225] A plurality of the electrodes have a positive electrode and a negative electrode,

[0226] The laminate is a laminated structure in which the positive electrode and the negative electrode are laminated with a separator therebetween.

[0227] Description of reference numerals

[0228] 1: Secondary battery; 10: Stack; 11: Positive electrode; 12: Negative electrode; 13: Separator; 20: Positive terminal; 30: Negative terminal; 50: Current collector; B1: Bottom of the first recess; B2: Bottom of the second recess; B3: Bottom of the third recess; J: Joint; P1: First concavo-convex pattern; P2: Second concavo-convex pattern; P3: Third concavo-convex pattern; R1: First concavo-convex region; R2: Second concavo-convex region; T1: First protrusion; U1: First recess; U2: Second recess; U3: Third recess; W1: First direction; W2: Second direction; W3: Third direction.

Claims

1. A secondary battery comprising: A laminated body having a plurality of electrodes laminated thereon; a plurality of current collectors electrically connected to the plurality of electrodes; and a terminal joined to the plurality of current collectors, The outer surface of the terminal in the joints between the plurality of current collectors and the terminal has a first concavo-convex region with a concavo-convex shape, The first concave-convex area has: A first concavo-convex pattern having a plurality of first concave portions; and Two second concave-convex patterns, each having a plurality of second concave portions whose areas when viewed from above the outer surface of the terminal are larger than those of the first concave portions, The first concavo-convex pattern is located between the two second concavo-convex patterns in the plan view.

2. The secondary battery according to claim 1, wherein The first concave-convex area extends along a first direction in the plan view, The first concavo-convex pattern is located between two second concavo-convex patterns in the first direction.

3. The secondary battery according to claim 1 or 2, wherein: The plurality of first recesses are arranged in a matrix along a second direction and a third direction that intersect each other in the plan view.

4. The secondary battery according to claim 3, wherein The plurality of second recesses are arranged along one of the second direction and the third direction in the plan view.

5. The secondary battery according to claim 3 or 4, wherein: The first concavo-convex region further has a third concavo-convex pattern, the third concavo-convex pattern having a plurality of third concave portions whose areas in the plan view are larger than the first concave portions and smaller than the second concave portions, The third concavo-convex pattern is adjacent to the first concavo-convex pattern in one of the second direction and the third direction. The second concavo-convex pattern is located at a position deviating from a range extending from the first concavo-convex pattern along the second direction and the third direction in the plan view.

6. The secondary battery according to any one of claims 1 to 5, wherein The outer surface of the current collector in the junction has a second concavo-convex region with a concavo-convex shape, The depth of the first concavo-convex region is shallower than the depth of the second concavo-convex region.

7. The secondary battery according to any one of claims 1 to 6, wherein The plurality of electrodes have positive electrodes and negative electrodes, The laminated body has a laminated structure in which the positive electrode and the negative electrode are laminated with a separator interposed therebetween.

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