Secondary battery

Abstract

The present invention relates to a secondary battery in which one of a first current collector (410) and a second current collector (440) has a first main surface and a through-hole (411) or a recessed portion formed in the first main surface, and the other of the first current collector (410) and the second current collector (440) has a second main surface and a protruding portion (442) protruding from the second main surface and disposed in the through-hole (411) or the recessed portion. A region of the first current collector (410) located around the through-hole (411) or the recess is welded to the second current collector (440).

Description

TECHNICAL FIELD

[0001] The present technology relates to a secondary battery. BACKGROUND

[0002] In a secondary battery, a current collecting structure connected to an electrode body housed in a case is provided. As a conventional current collecting structure, the current collecting structure described in Japanese Patent Application Publication No. 2019-125492 (JP 2019-125492 A) can be cited.

[0003] When a plurality of components are combined to constitute a current collecting structure, it is required to improve the reliability of a secondary battery by connecting the components more stably. The conventional current collecting structure still has room for improvement. SUMMARY

[0004] An object of the present technology is to provide a secondary battery with high reliability.

[0005] The present technology provides the following secondary battery.

[0006] [1] A secondary battery characterized by comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; a case housing the electrode body; and a first electrode terminal electrically connected to the first electrode, the electrode body including a first electrode tab electrically connected to the first electrode, the secondary battery further comprising a current collecting component electrically connecting the first electrode tab and the first electrode terminal, the current collecting component including a first current collector joined to the first electrode tab and a second current collector joined to the first current collector, the first current collector being electrically connected to the first electrode terminal via the second current collector, one of the first current collector and the second current collector having a first main surface and a through-hole or a recess formed in the first main surface, the other of the first current collector and the second current collector having a second main surface and a protrusion protruding from the second main surface and disposed in the through-hole or the recess, and a region of the first current collector located around the through-hole or the recess being joined to the second current collector by welding.

[0007] [2] The secondary battery according to [1], characterized in that the second current collector has a plurality of protrusions separated from each other, and the plurality of protrusions are disposed in one through-hole or one recess.

[0008] [3] The secondary battery according to [1] or [2], characterized in that the first current collector has a thin-walled portion formed around the through-hole or the recess, and a thick-walled portion formed at a position farther from the through-hole or the recess than the thin-walled portion and having a thickness greater than that of the thin-walled portion, and the first current collector is joined to the second current collector by welding in the thin-walled portion.

[0009] [4] The secondary battery according to [3], characterized in that, when viewed from a direction perpendicular to the first main surface, the thin-walled portion is formed to reach an outer periphery of the first current collector.

[0010] [5] The secondary battery according to any one of [1] to [4], characterized by further comprising an insulating member provided between the case and the second current collector, the insulating member having a region not opposed to the second current collector, and in the region not opposed, a positioning mechanism of the insulating member and the first current collector is provided.

[0011] [6] The secondary battery according to any one of [1] to [5], characterized in that the first current collector and the second current collector are plate-shaped members in which the first main surface and the second main surface are surfaces widest, the first current collector and the second current collector are overlaid in a thickness direction in a manner that the first main surface and the second main surface are in contact with each other, and a thickness of the first current collector and the second current collector is 5 mm or less.

[0012] [7] The secondary battery according to any one of [1] to [6], characterized in that, when viewed from a direction perpendicular to the first main surface, the through-hole or the recess is formed to be opened at an outer periphery of the first current collector.

[0013] [8] The secondary battery according to any one of [1] to [6], characterized in that, when viewed from a direction perpendicular to the first main surface, at least a part of the through-hole or the recess has an irregular shape, and the protrusion has a portion along the irregular shape.

[0014] [9] The secondary battery according to any one of [1] to [6], characterized in that, when viewed from a direction perpendicular to the first main surface, the through-hole or the recess has a shape having no axis of symmetry or point of symmetry, and the protrusion is similar to the through-hole or the recess.

[0015]

[10] The secondary battery according to any one of [1] to [9], characterized in that the first current collector and the second current collector are composed of copper or copper alloy.

[0016] The above and other objects, features, aspects and advantages of the present application will become more apparent from the following detailed description of the present application taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a front view showing a configuration of a secondary battery.

[0018] Figure 2 is a view showing the state of the secondary battery viewed from the direction of arrow II. Figure 1

[0019] Figure 3 is a view showing the state of the secondary battery viewed from the direction of arrow III. Figure 1

[0020] Figure 4 is a view showing the state of the secondary battery viewed from the direction of arrow IV. Figure 1

[0021] Figure 5 is a view showing the state of the secondary battery viewed from the direction of arrow V. Figure 1

[0022] Figure 6 is a front sectional view of the secondary battery. Figure 1

[0023] Figure 7 is a sectional view of the negative electrode (VII-VII sectional view in FIG. 7). Figure 8

[0024] Figure 8 is a front view showing the negative electrode.

[0025] Figure 9 is a sectional view of the positive electrode (IX-IX sectional view in FIG. 9). Figure 10

[0026] is a front view showing the positive electrode. Figure 10

[0027] Figure 11 is a view showing the configuration of the periphery of the negative current collector.

[0028] Figure 12 is a view showing the configuration of the periphery of the positive current collector.

[0029] Figure 13 is a flowchart showing the manufacturing method of the secondary battery.

[0030] Figure 14 is a view showing the state in which the current collector is joined to the first electrode body and the second electrode body.

[0031] Figure 15 is a view showing the state in which the sealing plate is assembled to the current collector on the negative electrode side.

[0032] Figure 16 is a view showing the state in which the first electrode body and the second electrode body are overlapped.

[0033] Figure 17 ​​​​​​​is a view showing a process of inserting the first electrode body and the second electrode body into the case main body.

[0034] Figure 18 is a view showing a state in which the sealing plate is assembled to the current collector on the positive electrode side.

[0035] Figure 19 is a view showing a state in which the opening of the case main body is sealed.

[0036] Figure 20 is a view showing a metal plate constituting the current collector.

[0037] Figure 21 is a perspective view showing the configuration of the negative electrode current collector.

[0038] Figure 22 is a view showing a state in which the first current collector is removed from the negative electrode current collector.

[0039] Figure 23 is a plan view showing the first current collector.

[0040] Figure 24 is a plan view showing the second current collector.

[0041] Figure 25 is a plan view showing a state in which the first current collector and the second current collector are combined.

[0042] Figure 26 is a view showing an example of combination of the through hole of the first current collector and the protrusion of the second current collector (1).

[0043] Figure 27 is a view showing an example of combination of the through hole of the first current collector and the protrusion of the second current collector (2).

[0044] Figure 28 is a view showing an example of combination of the through hole of the first current collector and the protrusion of the second current collector (3).

[0045] Figure 29 is a view showing an example of combination of the through hole of the first current collector and the protrusion of the second current collector (4). DETAILED DESCRIPTION

[0046] Hereinafter, an embodiment of the present technology will be described. In this embodiment, there are cases where the same reference signs are attached to the same or corresponding parts and the description thereof is not repeated.

[0047] In the following embodiments, the range of the present technology is not necessarily limited to the number, amount, etc. unless otherwise specifically described. In the following embodiments, each of the constituent elements is not necessarily essential for the present technology unless otherwise specifically described. In addition, the present technology is not limited to a technology that necessarily functions to achieve all the effects mentioned in the present embodiments.

[0048] In the present specification, the description of "comprise", and "include", "have" is open. That is, in the case of including a certain configuration, it can include other configurations other than the configuration, or it can not include.

[0049] When a geometric term, and a term indicating a positional / directional relationship such as the terms "parallel", "orthogonal", "inclined by 45°", "coaxial", "along", etc. are used in the present specification, these terms allow for manufacturing errors or slight variations. In the present specification, when terms such as "upper side", "lower side", etc. indicating a relative positional relationship are used, these terms are used as terms indicating a relative positional relationship in one state, and the relative positional relationship can be reversed or rotated to an arbitrary angle depending on the setting direction of each mechanism (for example, reversing the entire mechanism upside down, etc.).

[0050] In the present specification, "secondary battery" can include nickel-hydrogen batteries and sodium-ion batteries, in addition to lithium-ion batteries. In the present specification, "electrode" can collectively refer to both the positive electrode and the negative electrode.

[0051] In the drawings, when the electrode body possessed by the secondary battery is a laminated electrode body, the long side direction of the laminated surface is taken as the X direction, and when the electrode body is a wound electrode body, the direction along the winding axis thereof is taken as the X direction. In addition, the short side direction of the electrode body when viewed from the X direction is taken as the Y direction, and the long side direction of the electrode body when viewed from the X direction is taken as the Z direction. In order to facilitate understanding of the invention, there are parts in the drawings where the dimensions of each of the constituents are changed from the actual dimensions.

[0052] In the present specification, there are cases where the X direction is referred to as the "width direction" of the secondary battery 1, the electrode body 200, and the housing main body 110, the Z direction is referred to as the "height direction" of the secondary battery 1, the electrode body 200, and the housing main body 110, and the Y direction is referred to as the "thickness direction" of the secondary battery 1, the electrode body 200, and the housing main body 110.

[0053] (Overall configuration of the battery)

[0054] Figure 1 is a front view of the secondary battery 1 according to the present embodiment. Figures 2-5respectively, indicate the state of the secondary battery 1 as viewed in the direction of arrow II, the direction of arrow III, the direction of arrow IV, and the direction of arrow V, respectively. Figure 1 Figure 6 Figure 1

[0055] The secondary battery 1 can be mounted on a battery electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and the like. However, the use of the secondary battery 1 is not limited to the vehicle-mounted use.

[0056] As shown in FIG. 1, the secondary battery 1 includes a case 100, an electrode body 200, an electrode terminal 300, and a current collector 400. Figures 1-6

[0057] When a battery pack including the secondary battery 1 is configured, a plurality of secondary batteries 1 are arranged in the thickness direction thereof. The arranged secondary batteries 1 can be constrained by a constraint member in the arrangement direction (Y direction) to become a battery module, or can be directly supported by the side surface of the case of the battery pack without using the constraint member.

[0058] The case main body 110 is configured by a cylindrical member, and is preferably configured by a square cylindrical member. Thereby, a square secondary battery 1 can be obtained. The case main body 110 is made of metal. Specifically, the case main body 110 is configured by aluminum, an aluminum alloy, iron, or an iron alloy, or the like.

[0059] As shown in FIG. 1, the case main body 110 is configured by a cylindrical member, and is preferably configured by a square cylindrical member. Thereby, a square secondary battery 1 can be obtained. The case main body 110 is made of metal. Specifically, the case main body 110 is configured by aluminum, an aluminum alloy, iron, or an iron alloy, or the like. Figure 1 Figure 2 As shown in FIG. 1, the case main body 110 is configured by a cylindrical member, and is preferably configured by a square cylindrical member. Thereby, a square secondary battery 1 can be obtained. The case main body 110 is made of metal. Specifically, the case main body 110 is configured by aluminum, an aluminum alloy, iron, or an iron alloy, or the like. Figure 2

[0060] ​​​​​​In this embodiment, the outer casing 110 is formed to be longer in the width direction (X direction) than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1. The width of the outer casing 110 in the X direction is preferably 30 cm or more. This allows for the construction of a relatively large (high-capacity) secondary battery 1. The height of the outer casing 110 in the Z direction is preferably 20 cm or less, more preferably 15 cm or less, and even more preferably 10 cm or less. This allows for the construction of a relatively low-height secondary battery 1, for example, improving vehicle mountability.

[0061] The outer casing body 110 includes a pair of first side faces 111 and a pair of second side faces 112. The pair of first side faces 111 form part of the side faces of the outer casing 100. The pair of second side faces 112 form the bottom and top surfaces of the outer casing 100. The pair of first side faces 111 and the pair of second side faces 112 are respectively arranged to intersect each other. The pair of first side faces 111 and the pair of second side faces 112 are connected at their respective ends. The area of ​​each of the pair of first side faces 111 is larger than the area of ​​each of the pair of second side faces 112.

[0062] like Figure 5 As shown, a gas discharge valve 150 is provided on one of the pair of second side portions 112, namely, second side portion 112A. The gas discharge valve 150 extends in the width direction (X direction) of the secondary battery 1. The gas discharge valve 150 extends from the center of the outer casing 110 in the X direction to a point that does not reach either end. The shape of the gas discharge valve 150 can be appropriately modified.

[0063] The thickness of the plate-shaped component in the gas discharge valve 150 is thinner than the thickness of the plate-shaped components other than the gas discharge valve 150 in the housing body 110. As a result, when the pressure inside the housing 100 becomes above a predetermined value, the gas discharge valve 150 ruptures first than other parts in the housing body 110, thus discharging the gas inside the housing 100 to the outside.

[0064] like Figure 2 As shown, a joining portion 115 is formed on another second side surface portion 112B of a pair of second side surface portions 112. The joining portion 115 extends along the width direction (X direction) of the secondary battery 1. In the joining portion 115, the end edges of the plate-shaped members constituting the outer casing body 110 are joined together.

[0065] like Figure 3As shown, an opening 113 (first opening) is provided at the end of the outer casing 110 on the -X side in the X direction. The opening 113 is sealed by a sealing plate 120 (first sealing plate). A joint 115 is formed in the opening 113 to seal the opening 113. The opening 113 and the sealing plate 120 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction. The generally rectangular shape includes a rectangular shape or a shape with rounded corners, etc., that is substantially rectangular.

[0066] A negative terminal 301 (first electrode terminal) is provided on the sealing plate 120. The position of the negative terminal 301 can be changed appropriately. The negative terminal 301 is exposed on the outside of the sealing plate 120.

[0067] like Figure 4 As shown, an opening 114 (second opening) is provided at the end of the outer casing 110 on the +X side in the X direction. The opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 are opposite to each other. The opening 114 is sealed by a sealing plate 130 (second sealing plate). A joint 115 is formed in the opening 114 to seal it. The opening 114 and the sealing plate 130 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction.

[0068] A positive terminal 302 (second electrode terminal) and a liquid injection hole 134 are provided on the sealing plate 130. The positions of the positive terminal 302 and the liquid injection hole 134 can be changed appropriately.

[0069] Sealing plates 120 and 130 are made of metal. Specifically, sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0070] The negative terminal 301 is electrically connected to the negative terminal of the electrode body 200. The negative terminal 301 is mounted on the sealing plate 120, i.e., the housing 100. The negative terminal 301 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. A portion or layer of aluminum or an aluminum alloy may also be provided on the outer surface of the negative terminal 301. The negative terminal 301 is connected to the plate-shaped component 303.

[0071] The plate-shaped member 303 is located on the outside of the sealing plate 120. The plate-shaped member 303 is configured along the sealing plate 120. The plate-shaped member 303 is conductive. The plate-shaped member 303 is configured to ensure the connection area of ​​the busbar, etc., which electrically connects the secondary battery 1 and other adjacent secondary batteries. The connection between the negative terminal 301 and the plate-shaped member 303 can be formed, for example, by laser welding.

[0072] The positive terminal 302 is electrically connected to the positive terminal of the electrode body 200. The positive terminal 302 is mounted on the sealing plate 130, i.e., the housing 100. The positive terminal 302 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. The positive terminal 302 is exposed on the outside of the sealing plate 130. The positive terminal 302 is connected to the plate-shaped component 304.

[0073] The plate-shaped member 304 is located on the outside of the sealing plate 130. The plate-shaped member 304 is configured along the sealing plate 130. The plate-shaped member 304 is conductive. The plate-shaped member 304 is configured to ensure the connection area of ​​the busbar, etc., which electrically connects the secondary battery 1 and other adjacent secondary batteries. The connection between the positive terminal 302 and the plate-shaped member 304 can be formed, for example, by laser welding.

[0074] The injection port 134 is sealed by a sealing component (not shown). Such sealing components can be, for example, blind-hole rivets or other metal parts.

[0075] Electrode body 200 is a flat electrode body having a positive electrode and a negative electrode (described later) stacked on top of each other. Specifically, electrode body 200 is a stacked electrode body in which multiple positive electrodes and multiple negative electrodes are alternately stacked with a diaphragm (not shown). However, in this specification, "electrode body" is not limited to a stacked electrode body, and may also be a wound electrode body in which strip-shaped positive electrodes and strip-shaped negative electrodes are wound together with a strip-shaped diaphragm. The diaphragm may, for example, be made of a polyolefin microporous membrane. When the electrode body is a stacked electrode body including multiple positive electrodes and multiple negative electrodes, positive electrode tabs disposed on each positive electrode can be stacked to form a positive electrode tab group, and negative electrode tabs disposed on each negative electrode can be stacked to form a negative electrode tab group.

[0076] like Figure 6 As shown, the outer casing 100 houses the electrode body 200. Figure 6 In the following section, the first electrode 201, which will be described later, will be illustrated. The first electrode 201 is housed within the outer casing 100 with its long side parallel to the X direction.

[0077] Specifically, inside the insulating sheet (not shown) disposed within the housing 100, one or more stacked electrode bodies are housed together with an electrolyte (not shown). A solid electrolyte may also be used instead of the electrolyte.

[0078] The first electrode 201 includes a generally rectangular main body, a negative electrode tab group 220, and a positive electrode tab group 250. The negative electrode tab group 220 is located at the end of the main body on the -X side in the X direction. The positive electrode tab group 250 is located at the end of the main body on the +X side in the X direction.

[0079] The negative electrode tab group 220 and the positive electrode tab group 250 are formed to protrude from the central part of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0080] The current collector 400 includes a negative current collector 400A and a positive current collector 400B. The electrode body 200 is electrically connected to the negative terminal 301 and the positive terminal 302 via the current collector 400.

[0081] The negative current collector 400A is electrically connected to the negative electrode tab assembly 220 and the negative terminal 301. The negative current collector 400A can be made of a conductive material (more specifically, a metal such as copper or a copper alloy).

[0082] The positive current collector 400B is electrically connected to the positive electrode tab assembly 250 and the positive terminal 302. The positive current collector 400B can be made of a conductive material (more specifically, a metal such as aluminum or an aluminum alloy).

[0083] (Composition of electrode body 200)

[0084] like Figure 8 As shown, the negative electrode 210 (first electrode) includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil. The negative electrode active material layer 212 is formed by coating a negative electrode active material layer slurry using a die coater.

[0085] A negative electrode tab 230, composed of a negative electrode core 211, is provided at one end of the negative electrode 210 in the width direction. When the negative electrodes 210 are stacked, multiple negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length of each negative electrode tab 230 in the protruding direction among the multiple negative electrodes 210 can be appropriately adjusted considering the connection state between the negative electrode tab group 220 and the negative current collector 400A. The shape of the negative electrode tab 230 is not limited to... Figure 8 The illustrated shape.

[0086] like Figure 10 As shown, the positive electrode 240 (second electrode) has a different polarity than the negative electrode 210. The positive electrode 240 includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is an aluminum foil or an aluminum alloy foil. The positive electrode active material layer 242 is formed on the positive electrode core 241 by coating a positive electrode active material layer slurry using a die-coating machine.

[0087] A positive electrode tab 260, composed of a positive electrode core 241, is provided at one end of the positive electrode 240 in the width direction. When the positive electrodes 240 are stacked, multiple positive electrode tabs 260 are stacked to form a positive electrode tab assembly 250. The length of each positive electrode tab 260 in the protruding direction among the multiple positive electrodes 240 can be appropriately adjusted considering the connection state between the positive electrode tab assembly 250 and the positive current collector 400B. The shape of the positive electrode tab 260 is not limited to... Figure 10 The illustrated shape.

[0088] A positive electrode protection layer 243 is disposed at the base of the positive electrode tab 260. However, it is not necessary to provide a positive electrode protection layer 243.

[0089] In a typical example, the thickness of the negative electrode tab 230 (one piece) is less than the thickness of the positive electrode tab 260 (one piece). In this case, the thickness of the negative electrode tab group 220 is less than the thickness of the positive electrode tab group 250.

[0090] (Connection structure between electrode 200 and current collector 400)

[0091] like Figure 11 , Figure 12 As shown, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 each include a positive electrode 240 and a negative electrode 210, respectively. The electrode body 200 may also be composed of three or more electrode bodies.

[0092] Electrode body 200 is formed by overlapping the first electrode body 201 and the second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged along the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0093] The first electrode body 201 includes: a positive electrode tab assembly 250, disposed at one end of the first electrode body 201. Figure 12 ), and is electrically connected to the positive electrode 240; and the negative electrode tab group 220 (first electrode tab), is disposed at the end of the other side of the first electrode body 201 ( Figure 11 ), and electrically connected to the negative terminal 210.

[0094] The second electrode 202 includes: a positive electrode tab assembly 280, disposed at one end of the second electrode 202. Figure 12 ), and is electrically connected to the positive electrode 240; and the negative electrode tab group 270 (second electrode tab), is disposed at the end of the other side of the second electrode body 202 ( Figure 11 ), and electrically connected to the negative terminal 210.

[0095] like Figure 11(As shown in the diagram of the negative electrode side structure), the negative electrode tabs 220 and 270 are electrically connected to the current collector 410 (negative current collector 400A). The current collector 410 (first current collector) for connecting the negative electrode tabs 220 and 270 can be made of a metal plate-shaped component. Alternatively, the current collector 410 can be made of a single component.

[0096] The negative electrode tab assembly 220 has a bent portion 221. The bent portion 221 is the bent part of the negative electrode tab assembly 220. The negative electrode tab assembly 270 has a bent portion 271. The bent portion 271 is the bent part of the negative electrode tab assembly 270.

[0097] Negative electrode tab group 220 and negative electrode tab group 270 are bent in opposite directions with their front ends approaching each other.

[0098] In addition, in the embodiment, the front ends of the negative electrode tab group 220 and the negative electrode tab group 270 are separated from each other, but the technology is not limited to this configuration, and the front ends of the negative electrode tab group 220 and the negative electrode tab group 270 can also be in contact with each other.

[0099] The current collector 410 electrically connects the negative terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. The current collector 410 has a long side in the Z direction and a short side in the Y direction.

[0100] Negative electrode tab assembly 220 and negative electrode tab assembly 270 are respectively located at the junction 410A described later (see reference). Figure 14 It is joined to the current collector 410. The joint 410A can be formed, for example, by ultrasonic joining, resistance welding, laser welding, seam closing, etc.

[0101] An insulating component 510 is disposed between the plate-shaped component 303 and the sealing plate 120. An insulating component 530 is disposed between the current collector 410 and the sealing plate 120. However, the negative terminal 301 can also be electrically connected to the sealing plate 120, and the sealing plate 120 can also function as the negative terminal 301.

[0102] Alternatively, a spacer (not shown) may be disposed between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode tabs 220 and 270). The spacer may be made of an insulating resin component. The negative electrode tabs 220 and 270 are protected by passing through the spacer.

[0103] like Figure 12 As shown in the diagram (for the positive electrode side), positive electrode tab group 250 and positive electrode tab group 280 are electrically connected to current collector 430 (positive current collector 400B), respectively. More specifically, positive electrode tab group 250 is connected to current collector 431, and positive electrode tab group 280 is connected to current collector 432.

[0104] The lengths of the positive tab groups 250, 280 can be appropriately changed. It is preferable that the lengths of the positive tab groups 250, 280 are the same as each other, but they can be different from each other. There are cases where the lengths of the positive tab groups 250, 280 are shorter than those of the negative tab groups 220, 270, and cases where they are longer than those of the negative tab groups 220, 270.

[0105] The current collector 431 for joining the positive tab group 250 is composed of a laminate of a plurality of metal plates 4300 (refer to Figure 20 ) described later. Similarly, the current collector 432 for joining the positive tab group 280 is composed of a laminate of a plurality of metal plates 4300 (refer to Figure 20 ). In the current collectors 431, 432, the number of the metal plates 4300 laminated is two or more, for example, preferably three or more, and more preferably five or more. In addition, it can be, for example, 20 or less, preferably 15 or less, and more preferably 10 or less.

[0106] The current collectors 431, 432 electrically connect the positive terminal 302 with the positive tab group 250 and the positive tab group 280. The current collectors 431, 432 are joined to the current collector 420 in a state of being bent, and are electrically connected to the positive terminal 302.

[0107] The current collector 430 is composed of two current collectors 431, 432, and a more stable current collecting structure can be constituted. However, the scope of the present technology is not limited to this, and for example, the positive tab group 250 and the positive tab group 280 can be joined to one current collector 430. By joining the positive tab group 250 and the positive tab group 280 to one current collector 430, the joining process can be simplified (the number of times can be reduced).

[0108] In the example of Figure 12 , the current collectors 431, 432 are joined to the current collector 420 at a portion where the current collectors 431, 432 overlap each other (the joining portion 420A of Figure 18 ). However, the scope of the present technology is not limited to this, and the current collectors 431, 432 can be joined to the current collector 420 at positions where they are separated from each other or adjacent to each other in the current collector 420.

[0109] The positive tab group 250 and the positive tab group 280 are joined to the current collectors 431, 432 at joining portions 431A, 432A (refer to Figure 14 ) described later, respectively. The joining portions 431A, 432A can be formed, for example, by ultrasonic joining, resistance welding, laser welding, caulking, or the like.

[0110] The junction 431A of the current collector 431 and the positive electrode tab group 250, and the junction 432A of the current collector 432 and the positive electrode tab group 280 are formed at positions that are separated from each other in the XY plane.

[0111] like Figure 12 As shown, in the X direction, a positive electrode tab assembly 250 is disposed between the end of the current collector 431 on the electrode body 200 side (left side in the figure) and the end of the current collector 432 on the electrode body 200 side (left side in the figure) (the gap between current collectors 431 and 432). A positive electrode tab assembly 280 can be disposed in the gap between current collectors 431 and 432, or both positive electrode tab assemblies 250 and 280 can be disposed in the gap between current collectors 431 and 432. Therefore, the gap between current collectors 431 and 432 can be effectively utilized.

[0112] An insulating component 520 is disposed between the plate-shaped component 304 and the sealing plate 130. An insulating component 540 is disposed between the positive terminal 302 and the sealing plate 130. However, the positive terminal 302 can also be electrically connected to the sealing plate 130, and the sealing plate 130 can also function as the positive terminal 302.

[0113] Alternatively, a spacer (not shown) may be disposed between the sealing plate 130 and the main body of the electrode body 200 (excluding the positive electrode tabs 250 and 280). The spacer may be made of an insulating resin component. The positive electrode tabs 250 and 280 are protected by passing through the spacer.

[0114] (Manufacturing process of secondary battery 1)

[0115] The manufacturing method of the secondary battery according to this embodiment will be described below. Figure 13 This is a flowchart illustrating the manufacturing method of secondary battery 1.

[0116] like Figure 13As shown, the method of manufacturing the secondary battery 1 includes a process of making the first electrode body 201 and the second electrode body 202 (S1), a process of joining the negative tab group 220 and the negative tab group 270 to the current collector 410 (S2), a process of joining the positive tab group 250 to the current collector 431 (S3), a process of joining the positive tab group 280 to the current collector 432 (S4), a process of electrically connecting the current collector 410 to which the negative tab group 220 and the negative tab group 270 are joined to the negative terminal 301 (S5), a process of overlapping the first electrode body 201 and the second electrode body 202 (S6), a process of assembling the separator and the insulating sheet to the electrode body 200 (S7), a process of inserting the first electrode body 201 and the second electrode body 202 into the case main body 110 (S8), a process of electrically connecting the current collectors 431 and 432 to which the positive tab groups 250 and 280 are joined to the positive terminal 302 (S9), a process of joining the sealing plates 120 and 130 to the case main body 110 to seal the openings 113 and 114 (S10), and a process of performing a leak inspection (S11).

[0117] Figures 14-19 is a view showing each process in the method of manufacturing the secondary battery 1.

[0118] In the process of making the first electrode body 201 and the second electrode body 202 (S1), it is preferable that the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 are each cut by a portion of the leading end so that the length of the leading end becomes the same length at the time of bundling.

[0119] As shown in Figure 14 After the first electrode body 201 and the second electrode body 202 are made, the negative tab groups 220 and 270 are joined to the current collector 410 (S2), the positive tab group 250 is joined to the current collector 431 (S3), and the positive tab group 280 is joined to the current collector 432 (S4).

[0120] The negative tab groups 220 and 270 are joined to the current collector 410 at the joining portion 410A. The positive tab group 250 is joined to the current collector 431 at the joining portion 431A. The positive tab group 280 is joined to the current collector 432 at the joining portion 432A.

[0121] The current collector 431, the first electrode body 201, the current collector 410, the second electrode body 202, and the current collector 432 are arranged in order in the arrow DR1 direction.

[0122] In Figure 14In the example of FIG. 1, in the height direction of the first electrode body 201 and the second electrode body 202, the current collector 410 and the current collectors 431 and 432 are disposed so as to be offset from the center of the first electrode body 201 and the second electrode body 202 toward one side. In addition, in the height direction of the first electrode body 201 and the second electrode body 202, the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 are respectively disposed so as to be offset from the center of the first electrode body 201 and the second electrode body 202 toward one side.

[0123] However, the scope of the present technology is not limited to this, and the current collector 410 and the current collectors 431 and 432 can also be disposed at the center of the first electrode body 201 and the second electrode body 202 in the height direction of the first electrode body 201 and the second electrode body 202. In addition, the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 can also be respectively disposed at the center of the first electrode body 201 and the second electrode body 202 in the height direction of the first electrode body 201 and the second electrode body 202.

[0124] As shown in FIG. 1, the current collector 410 engaged with the negative tab group 220 and the negative tab group 270 is assembled to the sealing plate 120. The sealing plate 120 has the current collector 440 (second current collector) and the negative terminal 301 pre-installed. The current collector 410 is assembled to the sealing plate 120 via the current collector 440. The current collector 410 is engaged with the current collector 440 at an engagement portion 440A. The engagement portion 440A can be formed by laser welding or the like, for example. As a result of the above, the current collector 410 is electrically connected to the negative terminal 301 (S5). Figure 15

[0125] As shown in FIG. 1, the negative tab group 220 and the negative tab group 270 are bent in the thickness direction of the first electrode body 201 and the second electrode body 202 (a direction orthogonal to the DR1 direction of the first electrode body 201 and the second electrode body 202) so as to overlap the first electrode body 201 and the second electrode body 202 (S6). Here, the negative tab group 220 and the negative tab group 270 are bent so that the leading end portions thereof face each other. Figure 16 Figure 14 Figure 15 In the case of causing the first electrode body 201 and the second electrode body 202 to "overlap", the first electrode body 201 and the second electrode body 202 can directly overlap, or other components can be disposed between the first electrode body 201 and the second electrode body 202. In addition, the first electrode body 201 and the second electrode body 202 can be fixed by a tape or the like, or can not be fixed.

[0126] In the case of causing the first electrode body 201 and the second electrode body 202 to "overlap", the first electrode body 201 and the second electrode body 202 can directly overlap, or other components can be disposed between the first electrode body 201 and the second electrode body 202. In addition, the first electrode body 201 and the second electrode body 202 can be fixed by a tape or the like, or can not be fixed.

[0127] ​​​The aforementioned spacer and insulating sheet are assembled onto the electrode body 200 (S7). However, in this technology, the spacer and insulating sheet are not necessarily essential components. The insulating sheet does not necessarily need to cover the entire surface of the electrode body 200. When the electrode body 200 is covered with an insulating sheet, it is preferable that the spacer is also covered by the insulating sheet.

[0128] like Figure 17 As shown, the first electrode 201 and the second electrode 202, which overlap each other, are inserted into the outer casing 110 with the current collector 430 side as the front end (S8).

[0129] When the electrode body 200 is inserted into the outer casing 110, the electrode body 200 can be pulled from the positive electrode side or pressed from the negative electrode side. When the electrode body 200 is pressed from the negative electrode side, the negative electrode tab group 220 and the negative electrode tab group 270 can be bent simultaneously.

[0130] like Figure 18 As shown, after the electrode body 200 is inserted into the housing body 110, the current collector 430, which is engaged with the positive electrode tab group 250 and the positive electrode tab group 280, is assembled onto the sealing plate 130. The current collector 420 and the positive terminal 302 are pre-installed on the sealing plate 130. The current collector 430 is assembled onto the sealing plate 130 via the current collector 420. The current collector 410 is engaged with the current collector 420 at the joint 420A. The joint 420A can be formed, for example, by laser welding. The result is that the current collector 430 is electrically connected to the positive terminal 302 (S9).

[0131] After electrically connecting the current collectors 431 and 432, which are connected to the positive electrode tabs 250 and 280, and the positive terminal 302, the current collectors 431 and 432 are bent together with the positive electrode tabs 250 and 280. Figure 12 The shape shown. Preferably, current collectors 431 and 432 are bent simultaneously, but current collectors 431 and 432 can also be bent sequentially.

[0132] like Figure 19 As shown, sealing plates 120 and 130 are engaged with the outer casing 110 (S10). Sealing plate 120 seals the opening 113 of the outer casing 110, and sealing plate 130 seals the opening 114 of the outer casing 110. Thus, the first electrode 201 and the second electrode 202 are housed in the outer casing 100.

[0133] After the above-described procedures, a leak check and other inspections are performed (S11). After the leak check, the secondary battery 1 is dried to remove moisture from the casing 100. Then, electrolyte is injected into the interior of the casing 100 through the injection hole 134. During electrolyte injection, the casing 100 is tilted with the sealing plate 130 on top and the sealing plate 120 on the bottom, and electrolyte is injected into the interior of the casing 100 through the injection hole 134 of the sealing plate 130. Then, vacuum charging is performed. During vacuum charging, the injection hole 134 may be temporarily sealed. Then, the injection hole 134 is sealed, and the secondary battery 1 is completed.

[0134] The order of the insertion process of electrode 200 and the connection process of current collector is not limited to the example above. For example, the order of the joining process (S2 to S4) of current collectors 410, 431, and 432 can be appropriately changed.

[0135] In this embodiment, an example is described in which the current collector 430 is electrically connected to the positive terminal 302 in a state where the first electrode 201 and the second electrode 202 are completely disposed within the housing body 110 after the process of inserting the first electrode 201 and the second electrode 202 into the housing body 100 (S8) is completed (S9). However, it is also possible to electrically connect the positive terminal 302 to the electrode 200 before the insertion process (S8) of the electrode 200 into the housing body 110 is completely completed (midway through the insertion process) (S9).

[0136] In this embodiment, an example of bending the current collectors 431 and 432 after the step (S9) of electrically connecting the current collectors 431 and 432 to the positive terminal 302 is described. However, it is also possible to deform the current collectors 431 and 432 before the step (S9) of electrically connecting the current collectors 431 and 432 to the positive terminal 302.

[0137] (Composition of metal plate 4300)

[0138] like Figure 20 As shown, the metal plate 4300 includes a first region 430A that is engaged with the positive electrode tabs 250 and 280, a second region 430B that is engaged with the current collector 420, and a connecting portion 430C, a hole 430D, and a cutout 430E disposed between the first region 430A and the second region 430B.

[0139] In forming the current collector 430, the plurality of metal plates 4300 can be joined to each other in the first region 430A and the second region 430B. The joining of the plurality of metal plates 4300 to each other is preferably performed by, for example, ultrasonic joining, diffusion joining, or the like. In the case of diffusion joining, the plurality of metal plates 4300 are preferably joined to each other by applying pressure to the stacked metal plates 4300 in a state where the stacked metal plates 4300 are heated at a temperature lower than the melting point of the metal plates 4300. The joining of the plurality of metal plates 4300 to each other is performed before the other conductive members (the positive electrode tab groups 250, 280, and the current collector 420) are joined to the first region 430A and the second region 430B.

[0140] The connection portion 430C of the current collector 430 preferably includes a region in which the plurality of metal plates 4300 are not joined to each other. Thus, the current collector 430 is easily bent at the connection portion 430C. The portion of the metal plates 4300 that is bent preferably includes a region in which the plurality of metal plates 4300 are not joined to each other. In addition, the plurality of metal plates 4300 are preferably not joined to each other in the entirety of the portion of the metal plates 4300 that is bent. There can also be a portion in which the plurality of metal plates 4300 are not joined to each other in regions other than the connection portion 430C (the first region 430A and the second region 430B).

[0141] In the region in which the plurality of metal plates 4300 are not joined to each other, the metal plates 4300 can abut each other. In addition, there can be a slight gap between the metal plates 4300. In the region in which the plurality of metal plates 4300 are not joined to each other, the metal plates 4300 are not welded or the like to each other, and a clear boundary is present between the metal plates 4300. For example, a natural oxide film is present on the surface of each metal plate 4300.

[0142] By providing the hole portion 430D and the notch 430E in the connection portion 430C, the cross-sectional area of the connection portion 430C can be reduced, and the current collector 430 is easily bent at the connection portion 430C. In addition, the connection portion 430C can function as a fuse portion.

[0143] The metal plates 4300 can be composed of, for example, aluminum or an aluminum alloy. The thickness of one metal plate 4300 is preferably greater than the thickness of one positive electrode tab 260, and is preferably about three times or more (more preferably about five times or more) the thickness of one positive electrode tab 260.

[0144] (Structure of the Negative Current Collector 400A)

[0145] Next, the structure of the negative current collector 400A will be described with reference to Figures 21-25 to the structure of the negative current collector 400A.

[0146] AsFigures 21-25 As shown, the current collectors 410 and 440 constituting the negative electrode current collector 400A are both composed of plate-shaped members, which are stacked on the insulating member 530 with their respective main surfaces (first main surface and second main surface) facing each other along the thickness direction. The thickness of the current collector 410 (thick-walled portion 410C) and the current collector 440 is preferably about 5 mm or less (more preferably about 2 mm or less). However, the current collectors 410 and 440 in this technology may also have an L-shaped form that allows the plate-shaped members to bend.

[0147] like Figure 21 and Figure 23 As shown, a thin-walled portion 410B with a relatively small thickness and a thick-walled portion 410C with a greater thickness than the thin-walled portion 410B are formed on the main surface of the current collector 410. When viewed from the thickness direction of the current collector 410 (the direction perpendicular to the first main surface), the thin-walled portion 410B is formed to reach the outer periphery of the current collector 410. A line is formed along the thickness direction of the thin-walled portion 410B. Figure 23 A through hole 411 extending perpendicularly to the paper surface. The thickness of the thin-walled portion 410B is preferably about 0.1 mm or more, more preferably about 0.3 mm or more, and even more preferably about 0.5 mm or more. The thickness of the thin-walled portion 410B is preferably about 2 mm or less, more preferably about 1 mm or less, and even more preferably about 0.7 mm or less.

[0148] A stepped difference is provided between the thin-walled portion 410B and the thick-walled portion 410C. A protrusion 412 protruding toward the insulating member 530 is formed at the end of the thick-walled portion 410C away from the thin-walled portion 410B.

[0149] like Figure 22 and Figure 24 As shown, a through hole 441 and a protrusion 442 are formed on the main surface of the current collector 440. The negative terminal 301 is inserted through the through hole 441. The protrusion 442 faces the... Figure 24 The paper protrudes vertically (near the front).

[0150] like Figure 25 As shown, when current collectors 410 and 440 are overlapped, the protrusion 442 of current collector 440 is disposed within the through hole 411 of current collector 410. This fitting suppresses positional misalignment between current collectors 410 and 440. A fitting gap may also be formed between the protrusion 442 and the through hole 411. This fitting gap (shortest distance) is preferably about 1.0 mm or less, more preferably about 0.5 mm or less.

[0151] exist Figure 25In this example, multiple (two) protrusions 442 that are separate from each other are disposed within a through hole 411. This suppresses the relative rotation of the current collectors 410 and 440. Furthermore, compared to the case where there is only one protrusion 442 with a relatively large diameter, the through hole 411 and the protrusion 442 can be easily fitted together.

[0152] The current collectors 410 and 440 are welded together at a joint 440A located around the through hole 411 into which the protrusion 442 is inserted. More specifically, the joint 440A (laser-welded part) is formed together with the through hole 411 on the thin-walled portion 410B. The joint 440A extends in a straight line, substantially parallel to the long side direction of the through hole 411. Two joints 440A are formed such that they sandwich the through hole 411 from both sides in the short side direction. However, the formation of the joint 440A is not limited to this.

[0153] The joint portion 440A is provided near the through hole 411. More specifically, the joint portion 440A is configured to form a gap of about 0.1 mm or more (more preferably about 0.3 mm or more, and even more preferably about 0.5 mm or more) and about 5 mm or less (more preferably about 3 mm or less) between it and the outer edge of the through hole 411.

[0154] like Figure 22 As shown, the insulating member 530 has a region 531 that does not oppose the current collector 440, and a recess 532 provided in the region 531. The region 531 directly opposes the current collector 410. Alternatively, a through hole may be provided instead of the recess 532. When the current collectors 410 and 440 are combined on the insulating member 530, the protrusion 412 of the current collector 410 is disposed in the recess 532 of the insulating member 530. The recess 532 and the protrusion 412 constitute a positioning mechanism that suppresses the positional displacement of the insulating member 530 and the current collector 410 by fitting them together. As a result, the current collectors 410 and 440 can be disposed more stably, and the joint 440A can be formed more stably. In addition, even when impacts or vibrations are applied during the use of a secondary battery, the localized load on the joint 440A can be suppressed more effectively, and damage to the joint 440A can be suppressed.

[0155] Next, refer to Figures 26-29 The shapes of the through hole 411 of the current collector 410 and the protrusion 442 of the current collector 440 will be described. Figures 26-29 This shows the state of the through hole 411 and the protrusion 442 as viewed from the protruding direction of the protrusion 442.

[0156] exist Figure 26 In the example shown, a circular through hole 411 and a protrusion 442 are formed. According to... Figure 26In the illustrated example, the through-hole 411 and the protrusion 442 are easily molded. In addition, position displacement can be suppressed uniformly in all directions.

[0157] In Figure 27 In the illustrated example, a square through-hole 411 and a protrusion 442 are formed. The through-hole 411 and the protrusion 442 are similar in shape. According to Figure 27 In the illustrated example, the relative rotation of the current collectors 410, 440 can be suppressed by forming only one protrusion 442. In addition, when the relative position displacement of the current collectors 410, 440 occurs, since the inner wall of the through-hole 411 and the side wall surface of the protrusion 442 are in contact, the increase in the local load can be suppressed, and the damage to the joint portion 440A formed in the current collectors 410, 440 can be suppressed.

[0158] In Figure 28 In the illustrated example, the through-hole 411 has an irregular shape. That is, the through-hole 411 has a shape having no axis of symmetry or point of symmetry (not line symmetry or point symmetry). Also, the protrusion 442 has a shape following the irregular shape of the through-hole 411. According to Figure 28 In the illustrated example, positioning and rotation restriction in multiple directions can be performed by one through-hole 411 and one protrusion 442. In addition, assembly errors at the time of assembly of the current collectors 410, 440 can be suppressed.

[0159] In Figure 29 In the illustrated example, the through-hole 411 is formed so as to be opened in the outer periphery of the current collector 410. According to Figure 29 In the illustrated example, since the side portion of the through-hole 411 is opened, by slidingly moving the current collectors 410, 440 with respect to each other, the through-hole 411 and the protrusion 442 can be fitted.

[0160] In the present specification, a portion in which a side portion is partially opened as illustrated in Figure 29 is also referred to as a "through-hole" or a "recess". In addition, the combination of the example illustrated in Figures 26-29 may also be applied.

[0161] In the present embodiment, by fitting the through-hole 411 of the current collector 410 and the protrusion 442 of the current collector 440, the position displacement between the plurality of members in the current collecting structure can be suppressed. Thus, the current collector 410 and the current collector 440 can be stably connected, and a joint portion 440A with higher reliability can be formed.

[0162] By providing the through-hole 411 on the current collector 410 side, the state in which the protrusion 442 is disposed inside the through-hole 411 can be visually confirmed at the time of combining the current collectors 410, 440. In addition, the abutment state of the current collector 410 and the current collector 440 can also be confirmed via the through-hole 411.

[0163] Moreover, since the joining portion 440A is arranged in the vicinity of the through-hole 411 that suppresses positional displacement of the current collector 410, 440, the joining portion 440A can be formed in a region where the amount of positional displacement of the current collector 410, 440 is small, and thus the reliability of the welded joint in the joining portion 440A can be improved, and as a result, the reliability of the secondary battery 1 can be improved.

[0164] In addition, by arranging the joining portion 440A in the thin-walled portion 410B of the current collector 410, laser welding can be performed at a relatively low output, and generation of sputtering and damage to surrounding components accompanying the sputtering can be suppressed.

[0165] In addition, by providing the thin-walled portion 410B and the thick-walled portion 410C on one surface of the current collector 410, determination of the front and back surfaces of the current collector 410 becomes easy, and the assembly process of the current collector 410, 440 can be made efficient. By forming the thin-walled portion 410B so as to reach the outer edge of the current collector 410, molding of the current collector 410 including the thin-walled portion 410B becomes easy.

[0166] In the case where the current collector 410, 440 is composed of copper or a copper alloy, it is particularly required to improve the necessity of improving the reliability of the welded joint in the joining portion 440A. At this time, the effects brought about by suppressing positional displacement of the current collector 410, 440 and the insulating member 530 are particularly remarkable. However, the current collector 410, 440 can be an electrically conductive member (preferably a metal member), and the material of these members is not limited to copper or a copper alloy in the present technology.

[0167] In addition, by composing the current collector 410, 440 of a plate-shaped member having a thickness of a prescribed value or less (5 mm or less or 2 mm or less), the space occupied by the negative current collector 400A can be reduced in the thickness direction (X direction) of the current collector 410, 440. As a result, the energy density of the secondary battery 1 is improved.

[0168] In addition, in the present embodiment, by using the current collector 430 composed of a laminate of a plurality of metal plates 4300, a current collector 430 that is easily deformed while suppressing an increase in resistance can be provided. As a result, the positive current collector 400B can be downsized, and the energy density of the secondary battery 1 can be improved.

[0169] In addition, in the present embodiment, in the process (S2) of joining the current collector 410 to the negative tab group 220, 270, as shown in Figure 14The negative tab group 220, 270 is joined to the current collector 410 in a state in which the first electrode body 201 is disposed on one side of the current collector 410 and the second electrode body 202 is disposed on the other side of the current collector 410, as shown. In this state, since the main body portions of the first electrode body 201 and the second electrode body 202 and the current collector 410 are located at relatively far positions, the options of the method of joining are many, and the negative tab group 220, 270 can be made relatively short. By shortening the negative tab group 220, 270, the internal space of the case 100 can be effectively utilized to further increase the energy density of the secondary battery 1.

[0170] In addition, in the present embodiment, since the current collector 431 and the current collector 432 are bent in the same direction with respect to each other in a state in which the first electrode body 201 and the second electrode body 202 overlap, the space on the inner circumferential side of the bent portion of the current collector 431 can be efficiently utilized to dispose the current collector 432. As a result, the positive current collector 400B can be further downsized to increase the energy density of the secondary battery 1.

[0171] In addition, in the present embodiment, by joining the current collectors 431, 432 to the positive tab group 250, 280 in advance (S3, S4), the positive tab group 250, 280 can be protected from damage (deformation, breakage, and the like) in the subsequent overlapping process of the first electrode body 201 and the second electrode body 202 (S6) and the insertion process of the first electrode body 201 and the second electrode body 202 into the case main body 110 (S8). As a result, a secondary battery 1 with high reliability can be provided.

[0172] (Supplement)

[0173] In the present embodiment, an example in which a bent current collector 430 composed of a metal plate laminate is used on the positive side ( Figure 12 ) and a current collector 410 composed of a single member of metal is used on the negative side ( Figure 11 ) is described, but the scope of the present technology is not limited to this, and the same configuration as the negative side can be adopted on the positive side, or the reverse of the above can be adopted on the positive side and the negative side.

[0174] A recessed portion with a bottom can be provided instead of the through-hole 411 (current collector 410) of the present embodiment, and a through-hole can be provided instead of the recessed portion 532 (insulating member 530) of the present embodiment.

[0175] In the present embodiment, an example in which a through-hole 411 is provided in the current collector 410 and a protruding portion 442 is provided in the current collector 440 is described, but these can be reversed, and a configuration in which a protruding portion is provided in the current collector 410 and a through-hole or a recessed portion is provided in the current collector 440 can be adopted.

[0176] Also, instead of the protrusion 412 of the current collector 410 and the recess 532 of the insulating member 530, a recess can be provided in the current collector 410, and a protrusion can be provided in the insulating member 530.

[0177] In the present embodiment, an example in which two negative electrode tab groups 220, 270 are joined to the current collector 410 is described, but the number of electrode tab groups joined to the current collector 410 is not limited to two, and can be one or more than three.

[0178] In the present embodiment, an example in which an electrode tab group in which a plurality of electrode tabs are laminated is joined to a current collector is described, but the scope of the present technology is not limited thereto, and a configuration in which one electrode tab is joined to a current collector can also be employed.

[0179] Embodiments of the present application have been described, but all points of the embodiments disclosed herein should be considered as examples, and are not intended to limit the present application. The scope of the present application is represented by the technical solution, and is intended to include equivalents of the technical solution and all modifications within the scope thereof.

Claims

1. A secondary battery, characterized in that, The secondary battery has the following features: An electrode body includes a first electrode and a second electrode with a polarity different from that of the first electrode; A housing for the electrode body; and The first electrode terminal is electrically connected to the first electrode. The electrode body includes a first electrode tab that is electrically connected to the first electrode. The secondary battery also includes a current collector that electrically connects the first electrode tab to the first electrode terminal. The current collector includes a first current collector that is coupled to the first electrode tab, and a second current collector that is coupled to the first current collector. The first current collector is electrically connected to the first electrode terminal via the second current collector. One of the first current collector and the second current collector has a first main surface and a through hole or recess formed on the first main surface. The first current collector and the other of the second current collector have a second main surface and a protrusion protruding from the second main surface and disposed within the through hole or the recess. The area of ​​the first current collector located around the through hole or the recess is welded to the second current collector.

2. The secondary battery according to claim 1, characterized in that, The second current collector has a plurality of mutually separated protrusions. The plurality of protrusions are disposed within one of the through holes or within one of the recesses.

3. The secondary battery according to claim 1 or 2, characterized in that, The first current collector has: a thin-walled portion formed around the through hole or the recess; and a thick-walled portion formed at a position farther away from the through hole or the recess than the thin-walled portion, and having a thickness greater than the thin-walled portion. In the thin-walled portion, the first current collector is welded to the second current collector.

4. The secondary battery according to claim 3, characterized in that, When viewed from a direction perpendicular to the first main surface, the thin-walled portion is formed to reach the outer periphery of the first current collector.

5. The secondary battery according to claim 1 or 2, characterized in that, It also includes an insulating component disposed between the outer casing and the second current collector. The insulating component has a region that is not opposite to the second current collector. In the misaligned area, a positioning mechanism for the insulating component and the first current collector is provided.

6. The secondary battery according to claim 1 or 2, characterized in that, The first current collector and the second current collector are plate-shaped components in which the first main surface and the second main surface are respectively the widest surfaces. The first current collector and the second current collector overlap in the thickness direction such that the first main surface and the second main surface are in contact with each other. The thickness of the first collector and the second collector is less than 5 mm.

7. The secondary battery according to claim 1 or 2, characterized in that, When viewed from a direction perpendicular to the first main surface, the through hole or the recess is formed at the outer periphery of the first current collector.

8. The secondary battery according to claim 1 or 2, characterized in that, When viewed from a direction perpendicular to the first main surface, at least a portion of the through hole or the recess has an irregular shape, and the protrusion has a portion along the irregular shape.

9. The secondary battery according to claim 1 or 2, characterized in that, When viewed from a direction perpendicular to the first main surface, the through hole or the recess has a shape without an axis of symmetry or a point of symmetry, and the protrusion is similar in shape to the through hole or the recess.

10. The secondary battery according to claim 1 or 2, characterized in that, The first collector and the second collector are made of copper or copper alloy.

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