Secondary battery

Abstract

In the secondary battery, in a direction perpendicular to the first sealing plate, a surface on the first sealing plate side of the first region protrudes toward the first sealing plate side compared with a surface on the first sealing plate side of the second region and a surface on the first sealing plate side of the third region, and in a direction perpendicular to the first sealing plate, a surface on the electrode body side of the second collector member is provided with a surface on the electrode body side of the third collector member. The fourth region has a recess that is recessed toward the first sealing plate side than the fifth region and the sixth region, and at least a portion of the first region is disposed within the recess.

Description

Technical Field

[0001] The present technology relates to secondary batteries. Background Art

[0002] Japanese Patent No. 4537353 discloses a rectangular battery in which a positive electrode terminal is provided on one side surface of a battery case and a negative electrode terminal is provided on the other end. Summary of the Invention

[0003] In pursuit of secondary batteries with higher volumetric energy density and higher reliability, there is room for further improvement in the structure and assembly method of the current collecting portion.

[0004] The purpose of this technology is to provide a secondary battery with higher volume energy density and higher reliability.

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

[0006] [1] A secondary battery comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; a housing body having a first opening; a first sealing plate sealing the first opening; a first electrode tab electrically connected to the first electrode; a first current collecting member electrically connected to the first electrode tab; a second current collecting member joined to the first current collecting member; and a first electrode terminal electrically connected to the second current collecting member and provided on the first sealing plate, wherein the first current collecting member includes a first region, a second region, and a third region, the first region being disposed between the second region and the third region. The second current collecting member includes a fourth region, a fifth region, and a sixth region, the fourth region being arranged between the fifth region and the sixth region, the first electrode tab being connected to the first region, and a surface of the first region on the first sealing plate side protruding toward the first sealing plate compared with a surface of the second region on the first sealing plate side and a surface of the third region on the first sealing plate side in a direction perpendicular to the first sealing plate. In a direction perpendicular to the first sealing plate, on a surface of the second current collecting member on the electrode body side, the fourth region has a recessed portion that is recessed toward the first sealing plate side compared with the fifth region and the sixth region, and at least a portion of the first region is arranged in the recessed portion.

[0007] [2] The secondary battery as described in [1], wherein a first contact area is formed in which the second area abuts the fifth area, and further, a second contact area is formed in which the corresponding areas abut each other between at least one of the first area and the fourth area and between the third area and the sixth area.

[0008] [3] The secondary battery according to [2], wherein a joint portion where the first current collecting member and the second current collecting member are joined is provided at an end portion of the first contact region.

[0009] [4] The secondary battery according to [3], wherein a first gap exists near an end portion of the first contact region opposite to an end portion where the joining portion is formed.

[0010] [5] The secondary battery according to any one of [2] to [4], wherein the second contact region is formed between the third region and the sixth region.

[0011] [6] The secondary battery according to any one of [1] to [5], wherein the thickness of the fourth region is smaller than the thickness of the fifth region and the thickness of the sixth region.

[0012] [7] The secondary battery according to any one of [1] to [6], wherein the portion of the first current collecting member connected to the first electrode tab is closer to the third region than to the second region.

[0013] [8] The secondary battery according to any one of [1] to [7], wherein, in the longitudinal direction of the first sealing plate, an end portion of the third region protrudes outward relative to an end portion of the sixth region.

[0014] The foregoing and other objects, features, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view showing the structure of a secondary battery according to the embodiment.

[0016] Figure 2 It shows the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0017] Figure 3 It shows the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0018] Figure 4 It shows the direction of arrow IV. Figure 1 The diagram shows the state of the secondary battery.

[0019] Figure 5 It shows the direction of arrow V. Figure 1 The diagram shows the state of the secondary battery.

[0020] Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0021] Figure 7 It is a cross-sectional view of the negative plate.

[0022] Figure 8 It is a front view showing the negative electrode plate.

[0023] Figure 9 It is a cross-sectional view of the positive plate.

[0024] Figure 10 It is a front view showing the positive electrode plate.

[0025] Figure 11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown.

[0026] Figure 12 yes Figure 1 The secondary battery is shown in a cross-sectional view taken along line XII-XII.

[0027] Figure 13 This is a flowchart showing a method for manufacturing a secondary battery according to one embodiment.

[0028] Figure 14 This is a perspective view showing a state before two electrode bodies included in a secondary battery according to one embodiment are stacked.

[0029] Figure 15 yes Figure 14 The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0030] Figure 16 It is a perspective view showing a state where a holder and a spacer are attached to the electrode body.

[0031] Figure 17 It is a perspective view showing a state where a sealing plate is attached to the current collector on the negative electrode side.

[0032] Figure 18 yes Figure 17 The electrode body and the current collector are shown in cross-sectional view taken along line XVIII-XVIII.

[0033] Figure 19 This is a first perspective view showing the form of the spacer.

[0034] Figure 20 This is a second perspective view showing the form of the spacer.

[0035] Figure 21 It is a side view showing the positional relationship between the spacer and the insulating sheet.

[0036] Figure 22 It is a perspective view showing a state where the electrode body is inserted into the case body.

[0037] Figure 23 It is a perspective view showing a state where a sealing plate is attached to the current collector on the positive electrode side.

[0038] Figure 24 yes Figure 23 XXIV-XXIV cross-sectional view of the electrode body and current collector shown.

[0039] Figure 25 It is a perspective view showing the structure of a secondary battery.

[0040] Figure 26 It is a side view showing only the connection structure on the negative electrode side of the first sealing plate side.

[0041] Figure 27 It is a longitudinal cross-sectional view showing only the connection structure on the negative electrode side excluding the negative electrode tab group and the electrode body.

[0042] Figure 28 This is a perspective view showing a state before the sealing plate is fixed to the housing body.

[0043] Figure 29 This is a first perspective view showing another embodiment of the joint portion of the current collector.

[0044] Figure 30 This is a second perspective view showing another embodiment of the joint portion of the current collector.

[0045] Figure 31 This is a third perspective view showing another embodiment of the joint portion of the current collector.

[0046] Figure 32 This is a fourth perspective view showing another embodiment of the joint portion of the current collector.

[0047] Figure 33 This is a fifth perspective view showing another embodiment of the joint portion of the current collector. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present technology will be described. The same or corresponding parts may be denoted by the same reference numerals, and their description may not be repeated.

[0049] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc. unless otherwise specified. Furthermore, in the embodiments described below, individual components are not essential to the present technology unless otherwise specified. Furthermore, the present technology is not limited to components that necessarily exhibit all the effects described in the embodiments.

[0050] In this specification, the words “comprise,” “include,” and “have” are not limiting. That is, when a certain component is included, other components other than that component may be included, or other components may not be included.

[0051] In this specification, when geometric terms and expressions indicating positional and directional relationships are used, such as "parallel," "perpendicular," "oblique at 45°," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. In this specification, when expressions such as "upper" and "lower" are used to indicate relative positional relationships, these expressions are intended to indicate a relative positional relationship in a single state. These relative positional relationships can be reversed or rotated to any angle depending on the orientation of the various mechanisms (for example, by turning the entire mechanism upside down).

[0052] In this specification, "secondary battery" is not limited to lithium-ion batteries, but also includes other secondary batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the positive electrode and the negative electrode are collectively referred to as "electrodes".

[0053] In the accompanying drawings, when the electrode body of the secondary battery is a laminated electrode body, the longitudinal direction of the laminated surface is designated as the X direction. When the electrode body is a wound electrode body, the direction along the winding axis is designated as the X direction. Furthermore, when viewed from the X direction, the shorter side of the electrode body is designated as the Y direction, and when viewed from the X direction, the longer side of the electrode body is designated as the Z direction. To facilitate understanding of the present technology, the dimensions of various components in the accompanying drawings may be shown modified from their actual dimensions.

[0054] In this application specification, the first direction (X direction) is sometimes referred to as the "width direction" of the secondary battery, electrode body, and shell body, the second direction (Z direction) is similarly referred to as the "height direction" of the secondary battery or shell body, and the third direction (Y direction) is similarly referred to as the "thickness direction" of the secondary battery or shell body.

[0055] (Implementation: Overall Structure of a Battery)

[0056] Figure 1 It is a front view of the secondary battery 1 according to this embodiment. Figures 2 to 5 They are shown as viewed from the direction of arrow II, arrow III, arrow IV, and arrow V. Figure 1 The diagram shows the state of the secondary battery 1. Figure 6 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view.

[0057] 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), etc. However, the use of the secondary battery 1 is not limited to vehicle use.

[0058] like Figures 1 to 6 As shown, secondary battery 1 includes case 100, electrode assembly 200, electrode terminal 300, and current collector 400. Case 100 includes case body 110, sealing plate 120 (first sealing plate), and sealing plate 130 (second sealing plate).

[0059] To construct a battery pack containing secondary batteries 1, multiple secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 can be restrained in the stacking direction (Y direction) using restraining members to form a battery module, or the battery pack can be directly supported on the side surfaces of the battery pack casing without restraining members.

[0060] The case body 110 is formed of a cylindrical (preferably a square) member. This provides a square-shaped secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is formed of aluminum, an aluminum alloy, iron, or an iron alloy.

[0061] like Figure 1 as well as Figure 2 As shown, a sealing plate 120 (first wall) and a sealing plate 130 (second wall) are provided at both ends of the housing body. The housing body 110 can be formed by, for example, placing the ends of the bent plate-like members in contact with each other ( Figure 2 The illustrated joint 115 is joined together (e.g., laser welded) to form a rectangular cylindrical shape. The corners of the rectangular cylindrical shape may also have rounded corners. Furthermore, the secondary battery in this technology is not necessarily limited to a rectangular secondary battery.

[0062] In this embodiment, the case body 110 is formed longer in the width direction (X direction) of the secondary battery 1 than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1. The X-direction dimension (width) of the case body 110 is preferably approximately 30 cm or greater. This allows for a relatively large (high-capacity) secondary battery 1. The Z-direction dimension (height) of the case body 110 is preferably approximately 20 cm or less, more preferably approximately 15 cm or less, and even more preferably approximately 10 cm or less. This allows for a relatively low-height secondary battery 1, improving its mountability, for example, in a vehicle.

[0063] The shell body 110 includes a pair of first side portions 111 and a pair of second side portions 112. The pair of first side portions 111 constitute a portion of the side surface of the shell 100. The pair of second side portions 112 constitute the bottom portion and the top portion of the shell 100. The pair of first side portions 111 and the pair of second side portions 112 are respectively arranged in a mutually intersecting manner. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. Preferably, the area of each of the pair of first side portions 111 is larger than the area of each of the pair of second side portions 112.

[0064] like Figure 5 As shown, a gas discharge valve 150 is provided on the second side surface 112A of one of the pair of second side surfaces 112. The gas discharge valve 150 extends in the width direction (X direction) of the secondary battery 1. The gas discharge valve 150 extends in the X direction from the center of the case body 110 in the X direction to a point where it does not reach both ends. The shape of the gas discharge valve 150 can be modified as appropriate.

[0065] The thickness of the plate-shaped member at the gas discharge valve 150 is thinner than the thickness of the plate-shaped members of the housing body 110 other than the gas discharge valve 150. Therefore, when the pressure within the housing 100 exceeds a predetermined value, the gas discharge valve 150 ruptures preferentially over other portions of the housing body 110, allowing the gas within the housing 100 to be discharged to the outside.

[0066] like Figure 2 As shown, a joint portion 115 is formed on the other second side surface 112B of the pair of second side surfaces 112. The joint portion 115 extends in the width direction (X direction) of the secondary battery 1. At the joint portion 115, the end edges of the plate-like members constituting the case body 110 are joined.

[0067] like Figure 3 As shown, an opening 113 (first opening) is provided at the first end of the housing body 110 in the first direction (X direction). Opening 113 is sealed by a sealing plate 120. A joint 115 is formed in opening 113 to seal it. Opening 113 and sealing plate 120 have a generally rectangular shape with the Y direction as the short side and the Z direction as the long side. A generally rectangular shape includes a substantially rectangular shape or a substantially rectangular shape, such as a shape with rounded corners.

[0068] The sealing plate 120 (first sealing plate) is provided with a negative electrode terminal 301. The position of the negative electrode terminal 301 can be changed as appropriate.

[0069] like Figure 4As shown, an opening 114 (second opening) is provided at the second end of the housing body 110, opposite the first side in the first direction (X direction). Specifically, opening 114 is located at the end opposite opening 113, with openings 113 and 114 facing each other. Opening 114 is sealed by a sealing plate 130. A joint 115 is formed in opening 114 to seal it. Opening 114 and sealing plate 130 have a generally rectangular shape, with the shorter side extending in the Y direction and the longer side extending in the Z direction.

[0070] The sealing plate 130 (second sealing plate) is provided with a positive electrode terminal 302 and a liquid injection hole 134. The positions of the positive electrode terminal 302 and the liquid injection hole 134 can be changed as appropriate.

[0071] The sealing plates 120 and 130 are made of metal. Specifically, the sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0072] The negative electrode terminal 301 (first electrode terminal) is electrically connected to the negative electrode of the electrode assembly 200 . The negative electrode terminal 301 is attached to the sealing plate 120 , ie, the case 100 .

[0073] The positive electrode terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode assembly 200 . The positive electrode terminal 302 is attached to the sealing plate 130 , ie, the case 100 .

[0074] The negative electrode terminal 301 may be made of a conductive material (more specifically, a metal), such as copper or a copper alloy. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301 .

[0075] The positive electrode terminal 302 is made of a conductive material (more specifically, metal), and can be made of, for example, aluminum or an aluminum alloy.

[0076] The liquid injection hole 134 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used.

[0077] The electrode body 200 is a flat electrode body in which positive plates and negative plates described later are stacked. Specifically, the electrode body 200 is a laminated electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked via a separator 800 described later. However, in this specification, the "electrode body" is not limited to a laminated electrode body, and may also be a wound electrode body in which a strip-shaped positive plate and a strip-shaped negative plate are wound together via a strip-shaped separator. The separator may be composed of a microporous film made of polyolefin, for example. In the case where the electrode body is a laminated electrode body including a plurality of positive plates and a plurality of negative plates, the positive electrode tabs provided on each positive plate are stacked to form a positive electrode tab group, and the negative electrode tabs provided on each negative plate are stacked to form a negative electrode tab group.

[0078] like Figure 6 As shown in FIG. 1 , the housing 100 houses the electrode body 200. Figure 6 , a first electrode body 201 described later is illustrated. The first electrode body 201 is housed in the housing 100 so that its longitudinal direction is parallel to the X direction.

[0079] Specifically, inside the insulating sheet 700 (described later) located within the housing 100, one or more laminated electrode assemblies are housed along with an electrolyte solution (not shown). For example, the electrolyte solution (non-aqueous electrolyte) can be a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) at a volume ratio of 30:30:40 (at 25°C) with LiPF6 dissolved at a concentration of 1.2 mol / L. Alternatively, a solid electrolyte can be used.

[0080] The first electrode body 201 includes a substantially rectangular main body, a negative electrode tab group 220 (a first electrode tab group), and a positive electrode tab group 250 (a second electrode tab group).

[0081] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, described later. The negative electrode tab group 220 is located at the end of the first electrode body 201 on the first side in the first direction (X direction) relative to the main body. In this embodiment, the first side is the sealing plate 120 side. The positive electrode tab group 250 is located at the end of the first electrode body 201 on the second side in the first direction (X direction) relative to the main body. In this embodiment, the second side is the sealing plate 130 side.

[0082] The negative electrode tab group 220 and the positive electrode tab group 250 are formed so as to protrude from the center portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130 , respectively.

[0083] The current collector 400 includes a negative electrode current collector 400A and a positive electrode current collector 400B. The negative electrode current collector 400A and the positive electrode current collector 400B are each formed of a plate-shaped member. The electrode assembly 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400 .

[0084] The negative electrode current collector 400A is disposed on the sealing plate 120 via a resin insulating member. The negative electrode current collector 400A is electrically connected to the negative electrode tab group 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. Details of the negative electrode current collector 400A will be described later.

[0085] The positive electrode current collector 400B is placed on the sealing plate 130 via a resin insulating member. The positive electrode current collector 400B is electrically connected to the positive electrode tab group 250 and the positive electrode terminal 302. The positive electrode current collector 400B is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. The positive electrode tab group 250 can be electrically connected to the sealing plate 130 directly or via the positive electrode current collector 400B. In this case, the sealing plate 130 also functions as the positive electrode terminal 302. Details of the positive electrode current collector 400B will be described later.

[0086] (Structure of Electrode Body 200 )

[0087] Figure 7 is a cross-sectional view of the negative electrode plate 210 ( Figure 8 VII-VII section view in the figure), Figure 8 1 is a front view showing the negative electrode plate 210 .

[0088] like Figure 8 As shown, a plurality of negative electrode tabs 230 (first electrode tabs) formed of a negative electrode core 211 are provided at one end portion in the width direction of the negative electrode plate 210. When the negative electrode plates 210 are stacked, the plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length of each negative electrode tab 230 in the plurality of negative electrode plates 210 in the protruding direction can be appropriately adjusted in consideration of the connection state between the negative electrode tab group 220 and the negative electrode current collector 400A. The shape of the negative electrode tab 230 is not limited to Figure 7 The illustrated shape.

[0089] Figure 9 is a cross-sectional view of the positive electrode plate 240 ( Figure 10 IX-IX section view in the figure), Figure 10 1 is a front view showing the positive electrode plate 240 .

[0090] like Figure 10 As shown, a plurality of positive electrode tabs 260 (second electrode tabs) formed of a positive electrode core 241 are provided at one end in the width direction of the formed positive electrode plate 240. When the positive electrode plates 240 are stacked, the plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. The length of each of the positive electrode tabs 260 in the plurality of positive electrode plates 240 in the protruding direction can be appropriately adjusted in consideration of the connection state between the positive electrode tab group 250 and the positive electrode current collector 400B. The shape of the positive electrode tab 260 is not limited to Figure 10 The illustrated shape.

[0091] The positive electrode protection layer 243 is provided at the base of the positive electrode tab 260 . The positive electrode protection layer 243 does not necessarily need to be provided at the base of the positive electrode tab 260 .

[0092] In a typical example, the thickness of the negative electrode tab 230 (one) is smaller than the thickness of the positive electrode tab 260 (one). In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0093] (Connection Structure between Electrode Body 200 and Current Collector 400)

[0094] Figure 11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown in FIG. Figure 11 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 include a positive electrode (second electrode) and a negative electrode (first electrode), respectively. The electrode body 200 may also be composed of three or more electrode bodies.

[0095] The electrode body 200 is formed by stacking a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0096] The first electrode body 201 includes a negative electrode tab group 220. The negative electrode tab group 220 is electrically connected to a current collector 410 (negative electrode current collector) at a first end 205 in the X direction. The second electrode body 202 includes a negative electrode tab group 270. The negative electrode tab group 270 is electrically connected to another current collector 410 (negative electrode current collector) at a third end 207 in the X direction.

[0097] The negative electrode tab group 220 includes a bent portion 221 and a terminal portion 222. The bent portion 221 is a portion of the negative electrode tab group 220 that is bent relative to the terminal portion 222 on the side connected to the first electrode. The terminal portion 222 is the end portion of the negative electrode tab group 220 located on the side opposite to the side connected to the first electrode.

[0098] The negative electrode tab group 270 includes a bent portion 271 and a terminal portion 272. The bent portion 271 is a portion of the negative electrode tab group 270 that is bent relative to the terminal portion 272 on the side connected to the first electrode. The terminal portion 272 is the end portion of the negative electrode tab group 270 located on the opposite side to the side connected to the first electrode.

[0099] The negative electrode tab group 220 and the negative electrode tab group 270 are bent in opposite directions so that the distal ends 222 and 272 approach each other. In this embodiment, the distal ends 222 and 272 are separated, but the present invention is not limited to this configuration and the distal ends 222 and 272 may also contact each other.

[0100] The negative electrode current collector 400A is electrically connected to the negative electrode terminal 301 and the negative electrode tab group 220 and the negative electrode tab group 270. In this embodiment, the negative electrode current collector 400A is connected to the negative electrode terminal 301 between the electrode assembly 200 and the sealing plate 120.

[0101] The negative electrode current collector 400A includes two current collectors 410 (first current collecting members) and a current collector 430 (second current collecting member).

[0102] Current collector 410 is a plate-shaped member. It has a long side in the Z direction and a short side in the Y direction. Current collector 430 is a plate-shaped member. It has a long side in the Z direction and a short side in the Y direction. Current collectors 410 and 430 are arranged side by side in the X direction. Thus, current collectors 410 and 430 are composed of separate components.

[0103] The negative electrode tab group 220 is described later (see Figure 14 ) is joined to one current collector 410 at a joint portion 411. The negative electrode tab group 270 is joined to a current collector 410 at a joint portion 411. Figure 14 ) is joined to another current collector 410 at a joining portion 411. The joining portion 411 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, or the like. In this embodiment, the negative electrode tab group 220 and one current collector 410 are joined to the negative electrode tab group 270 and another current collector 410, for example, by ultrasonic welding.

[0104] The current collector 430 is joined to one current collector 410 and another current collector 410 at a joint portion (not shown) located at an end in the Z direction. The current collector 430 is connected to the negative electrode terminal 301. The connection between the current collector 430 and the negative electrode terminal 301 can be formed by caulking and / or welding, for example.

[0105] The negative electrode terminal 301 is exposed outside the sealing plate 120. The negative electrode terminal 301 is connected to the plate-shaped member 303. The negative electrode terminal 301 includes a region 301a made of copper or a copper alloy and a region 301b made of aluminum or an aluminum alloy. Preferably, the region 301a made of copper or a copper alloy is connected to the current collector 430.

[0106] The plate-shaped member 303 is located outside the sealing plate 120. It is positioned along the sealing plate 120. The plate-shaped member 303 is electrically conductive. It is positioned to ensure sufficient area for connection to a busbar, etc., that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the negative electrode terminal 301 and the plate-shaped member 303 can be achieved, for example, by laser welding.

[0107] An insulating member 510 is disposed between the plate-shaped member 303 and the sealing plate 120 . An insulating member 520 is disposed between the negative electrode terminal 301 and the sealing plate 120 . An insulating member 530 is disposed between the current collector 430 and the sealing plate 120 .

[0108] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120 . In addition, the sealing plate 120 may also function as the negative electrode terminal 301 .

[0109] A separator 600 (first separator), described below, is placed between the sealing plate 120 and the main body of the electrode assembly 200 (excluding the negative electrode tab group 220). The separator 600 is made of an insulating resin member. The negative electrode tab group 220 passes through the interior of the separator 600, thereby being protected by the separator 600. Alternatively, a configuration without the separator 600 (first separator) is possible.

[0110] The detailed structure of the spacer 600 will be described later. The spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of the spacer 600 serves as a guide to facilitate bending of the curved portions 221 and 271 when bending.

[0111] A resin insulating sheet 700 (electrode body support) is placed between the electrode body 200 and the case body 110. The insulating sheet 700 can be made of, for example, a resin. More specifically, the insulating sheet 700 can be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0112] Figure 12 yes Figure 1 The connection structure between the electrode body 200 and the current collector 400 on the positive electrode side of the secondary battery 1 in this embodiment is different from that on the negative electrode side in that the portion corresponding to one current collector 410 and another current collector 410 on the negative electrode side is composed of a single component.

[0113] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to the current collector 420 (positive electrode current collector) at the second end 206 in the X direction. The second electrode body 202 includes a positive electrode tab group 280. The positive electrode tab group 280 is electrically connected to the current collector 420 (positive electrode current collector) at the fourth end 208 in the X direction.

[0114] The positive electrode tab group 250 includes a bent portion 251 and a terminal portion 252. The bent portion 251 is a portion of the positive electrode tab group 250 that is bent relative to the terminal portion 252 on the side connected to the second electrode. The terminal portion 252 is the end portion of the positive electrode tab group 250 located on the side opposite to the side connected to the second electrode.

[0115] The positive electrode tab group 280 includes a bent portion 281 and a terminal portion 282. The bent portion 281 is a portion of the positive electrode tab group 280 that is bent relative to the terminal portion 282 on the side connected to the second electrode. The terminal portion 282 is the end portion of the positive electrode tab group 280 located on the side opposite to the side connected to the second electrode.

[0116] The positive electrode tab group 250 and the positive electrode tab group 280 are bent in opposite directions so that the terminal ends 252 and 282 approach each other. In this embodiment, the terminal ends 252 and 272 are separated, but the present invention is not limited to this structure. The terminal ends 252 and 282 may also contact each other.

[0117] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. In this embodiment, the positive electrode current collector 400B is connected to the positive electrode terminal 302 between the electrode assembly 200 and the sealing plate 130.

[0118] The positive electrode current collector 400B includes a current collector 420 and a current collector 440. A plate 460 is interposed as an insulating member between the current collector 420 and the current collector 440, and the current collector 420 and the current collector 440 are electrically joined at a position different from the cross section shown in the figure.

[0119] The current collector 420 is a plate-shaped member. The current collector 420 has a long side in the Z direction and a short side in the Y direction. The current collector 420 is composed of a single integral component.

[0120] The positive electrode tab group 250 and the positive electrode tab group 280 are connected at a joint 421 (see Figure 14 ) is joined to the current collector 420, which is composed of a single component. The joining portion 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, for example, by ultrasonic welding.

[0121] The current collector 440 is joined to the current collector 420 at a joint portion (not shown) located at an end in the Z direction. The current collector 440 is connected to the positive electrode terminal 302. The connection between the current collector 440 and the positive electrode terminal 302 can be formed by caulking and / or welding, for example.

[0122] The positive electrode terminal 302 is exposed outside the sealing plate 130 and is provided so as to reach the current collector 440 of the positive electrode current collector 400B provided on the inner surface of the sealing plate 130 . The positive electrode terminal 302 is connected to a plate-like member 304 .

[0123] The plate-shaped member 304 is located outside the sealing plate 130. It is positioned along the sealing plate 130. The plate-shaped member 304 is electrically conductive. It is positioned to ensure sufficient area for connection to a busbar, etc., that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the positive electrode terminal 302 and the plate-shaped member 304 can be achieved, for example, by laser welding.

[0124] An insulating member 510 is disposed between the plate-shaped member 304 and the sealing plate 130 . An insulating member 520 is disposed between the positive electrode terminal 302 and the sealing plate 130 . An insulating member 470 is disposed between the current collector 440 and the sealing plate 130 .

[0125] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130 . In addition, the sealing plate 130 may also function as the positive electrode terminal 302 .

[0126] A spacer 600 (second spacer) is placed between the sealing plate 130 and the main body of the electrode assembly 200 (excluding the positive electrode tab group 250 and 280). The spacer 600 is made of an insulating resin member. The positive electrode tab group 250 and 280 pass through the interior of the spacer 600, thereby being protected by the spacer 600. Alternatively, a configuration without the spacer 600 (second spacer) is possible.

[0127] The detailed structure of the spacer 600 will be described later. The spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of the spacer 600 serves as a guide to facilitate bending of the curved portions 251 and 281.

[0128] The above-mentioned resin insulating sheet 700 (electrode body holder) is arranged between the electrode body 200 and the case body 110 .

[0129] (Manufacturing Process of Secondary Battery 1)

[0130] Hereinafter, a method for manufacturing the secondary battery according to this embodiment will be described. Figure 13 This is a flowchart showing a method for manufacturing a secondary battery according to the first embodiment. Figure 14 This is a perspective view showing a state before two electrode bodies included in the secondary battery according to the first embodiment are stacked. Figure 15 yes Figure 14The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0131] like Figure 13 As shown, in the secondary battery manufacturing method according to this embodiment, first, a first electrode body 201 and a second electrode body 202 are fabricated (step S1). Preferably, the negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 are each partially cut off so that the ends have the same length when tied together.

[0132] like Figures 13 to 15 As shown, after the first electrode body 201 and the second electrode body 202 are fabricated, the negative electrode tab group 220 is joined to one current collector 410 (step S2). The negative electrode tab group 220 is joined to the one current collector 410 at a joining portion 411. Next, the negative electrode tab group 270 is joined to the other current collector 410 (step S3). The negative electrode tab group 270 is joined to the other current collector 410 at a joining portion 411.

[0133] Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged in this order in the first direction (DR1). The positive electrode tab group 250 is placed on one side of the current collector 420 in the first direction (DR1). With the positive electrode tab group 280 placed on the other side of the current collector 420 in the first direction (DR1), the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 (step S4). The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 at the joining portion 421.

[0134] In the height direction of the first electrode body 201 and the second electrode body 202, one current collector 410, the other current collector 410, and the current collector 420 are arranged to one side relative to the center of the first electrode body 201 and the second electrode body 202. This allows the current collector to be shorter and more compact.

[0135] The current collector 410, the other current collector 410, and the current collector 420 are not limited to this configuration. The current collector 410 and the current collector 420 may be arranged 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 this case, the negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 are arranged 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, respectively, corresponding to the current collector 410 and the current collector 420.

[0136] The order of the steps of joining the current collector 410 and the current collector 420 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above-described order, and the order may be changed. The steps of joining the current collector 410 to the first electrode body 201 and the second electrode body 202, respectively, are preferably performed before the step of superimposing the first electrode body 201 and the second electrode body 202, which will be described later, and are preferably performed before the step of joining the current collector 420 to the first electrode body 201 and the second electrode body 202.

[0137] Next, after the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, the first electrode body 201 and the second electrode body 202 are connected in the thickness direction (in the direction of the thickness of the first electrode body 201 and the second electrode body 202). Figure 14 as well as Figure 15 The positive electrode tab group 250 and the positive electrode tab group 280 are bent in a direction perpendicular to the DR1 direction to overlap the first electrode body 201 and the second electrode body 202 (step S5). In other words, the first electrode body 201 and the second electrode body 202 are brought together.

[0138] The phrase "overlapping the first and second electrode bodies" means that the first and second electrode bodies may be directly overlapped, or another member may be placed between the first and second electrode bodies. Furthermore, the first and second electrode bodies may be secured by a band or the like, or not. Furthermore, the first electrode body, current collector, and second electrode body may not be arranged in a straight line in the first direction (DR1 direction), and the first electrode body or the second electrode body may be tilted relative to the current collector with respect to the first direction (DR1 direction).

[0139] The positive electrode tab group 250 and the positive electrode tab group 280 are bent so that their distal ends face each other. In addition, the negative electrode tab group 220 and the negative electrode tab group 270 are also bent so that their distal ends face each other.

[0140] Figure 13 as well as Figure 16 : is a perspective view showing a state where a bracket and a spacer are installed on the electrode body. Figure 16 As shown, next, the separator 600 and the insulating sheet 700 are assembled on the electrode body 200 (step S6 ).

[0141] The insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers at least approximately 50% of the outer surface of the electrode body, and more preferably at least approximately 70%. The insulating sheet 700 preferably covers the entirety of four of the six surfaces of the generally rectangular (flat) electrode body 200, excluding the two surfaces each having the negative electrode tab group 220 and the positive electrode tab group 250 formed thereon.

[0142] Figure 17 It is a perspective view showing a state where the sealing plate 120 is attached to the current collector on the negative electrode side. Figure 18 yes Figure 17 The electrode body and the current collector are shown in cross-sectional view taken along line XVIII-XVIII. Figure 19 as well as Figure 20 These are first and second perspective views showing the configuration of the spacer 600 . Figure 21 700 is a side view showing the positional relationship between the spacer 600 and the insulating sheet 700. Figure 18 The housing body 110 is omitted.

[0143] like Figure 19 as well as Figure 20 As shown, spacer 600 is made of an insulating resin member. It includes a first member 612 and a second member 614, each surrounded by side walls on three sides; and a connecting wall 611 connecting one side wall of each of the first and second members 612, 614. Inside connecting wall 611, a protrusion 616 is provided, extending (in the Z direction) between first and second members 612, 614.

[0144] The first member 612 includes a first plate portion 617, which is arranged to connect three walls. The first plate portion 617 is provided with a plurality of oval first through-holes 617s. The shape and number of the first through-holes 617s can be selected as appropriate and are not limited to those shown. A first protrusion 612p, projecting outward, is provided in the region of the first member 612 opposite the first plate portion 617 (opposite the electrode body).

[0145] The second member 614 includes a second plate portion 618, which is arranged to connect the three walls. The second plate portion 618 is provided with a plurality of oval second through-holes 618s. The shape and number of the second through-holes 618s can be selected as appropriate and are not limited to those shown. A second protrusion 614p, projecting outward, is provided in the region of the second member 614 opposite the second plate portion 618 (opposite the electrode body).

[0146] The first plate portion 617 and the second plate portion 618 are located on the end face side of the electrode body. The plate portion may or may not abut against the end face of the electrode body. In the case of not abutting, the shortest distance from the electrode body is preferably within 2 mm, more preferably within 1 mm. Furthermore, by providing the first through hole 617s and the second through hole 618s, Figure 1When the secondary battery 1 shown is placed with the Z direction facing upward (the direction in which the openings 113 (first opening) and openings 114 (second opening) at both ends of the shell body 110 are arranged on the left and right), even if the electrolyte is pushed out of the electrode body during charging (generally due to expansion of the electrode plates) and flows out of the portion, it is easy to return to the electrode body during discharge (generally due to contraction of the electrode plates).

[0147] The outer dimensions of the spacers 600 (the first and second spacers) are preferably smaller than those of the electrode body 200. Since the electrode body 200 is wrapped around the insulating sheet 700, and the spacers 600 are also wrapped around the insulating sheet 700, making the outer dimensions of the spacers 600 smaller than those of the electrode body 200 improves the ease with which the electrode body 200 can be inserted into the case body 110.

[0148] like Figure 21 As shown, when the electrode body 200 is covered by the insulating sheet 700, it is preferable that the separator 600 is also covered by the insulating sheet 700. In this case, by passing the negative electrode tab group and the positive electrode tab group through the interior of the separator 600, the negative electrode tab group and the positive electrode tab group can be protected by the separator 600. Furthermore, by also covering the separator 600 with the insulating sheet 700, the negative electrode tab group and the positive electrode tab group can be further protected. In addition, it is preferable that the first protrusion 612p and the second protrusion 614p provided on the separator 600 are exposed from the insulating sheet 700.

[0149] like Figure 13 、 Figure 17 as well as Figure 18 As shown, after the negative electrode tab group 220 is joined to the current collector 410, the negative electrode tab group 270 is joined to the current collector 430, and the first electrode body 201 and the second electrode body 202 are superimposed, one current collector 410 and the other current collector 410 are electrically connected to the negative electrode terminal 301 via the current collector 430 (step S7). Alternatively, step S7 can be performed before step S6.

[0150] Specifically, the negative electrode tab group 220 and the negative electrode tab group 270 are bent so that the end portions 222 and 272 face each other.

[0151] The negative electrode terminal 301 and current collector 430 are attached to the sealing plate 120 via an insulating member. The current collector 430 is brought into contact with one current collector 410 and another current collector 410 in the X direction. The plate-shaped member 303 can be connected to the negative electrode terminal 301 at any time. The current collector 430, one current collector 410, and another current collector 410 are joined by laser welding between the sealing plate 120 and the insulating sheet 700.

[0152] Figure 22 : is a perspective view showing a state where the electrode body is inserted into the shell body. Figure 13 as well as Figure 22 As shown, after the first electrode body 201 and the second electrode body 202 are stacked, they are inserted into the case body 110 through the opening 113, with the current collector 420 side leading (step S8). At this time, the first electrode body 201 and the second electrode body 202 can be inserted into the case body 110 in a state where the negative electrode active material layer 212 protrudes toward the negative electrode tab 230 relative to the positive electrode active material layer 242 at the negative electrode tab 230 side of the first electrode body 201 and the second electrode body 202.

[0153] By bringing the sealing plate 120 and the main body of the electrode body 200 (the first electrode body 201 and the second electrode body 202) closer together, the negative electrode tab group 220 and the negative electrode tab group 270 are bent. In addition, it is preferable that the sealing plate 120 and the main body of the electrode body 200 disposed in the case body 110 are brought closer together. Figure 11 As shown, the negative electrode tab group 220 and the negative electrode tab group 270 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 221 and 271 approach the case body 110 in the Y direction.

[0154] After the sealing plate 120 is brought into contact with the housing body 110, the sealing plate 120 is temporarily joined to the housing body 110. By temporarily joining, the sealing plate 120 is partially joined to the opening 113 of the housing body 110. Thus, the sealing plate 120 is positioned relative to the housing body 110.

[0155] When the electrode body 200 is inserted into the case body 110, the electrode body 200 can be pulled from the current collector 420 side or pressed from the current collectors 410 and 430. When the electrode body 200 is pressed from the current collectors 410 and 430 sides, the negative electrode tab group 220 and the negative electrode tab group 270 can be bent simultaneously.

[0156] Figure 23 It is a perspective view showing a state where the sealing plate 130 is attached to the current collector on the positive electrode side. Figure 24 yes Figure 23 The electrode body and the collector are shown in the XXIII-XXIII cross-sectional view. Figure 24 In the embodiment, the housing body 110 is omitted.

[0157] like Figure 13 、 Figure 22 as well as Figure 23As shown, after the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 , the current collector 420 and the positive electrode terminal 302 are electrically connected (step S9 ).

[0158] Specifically, the positive electrode terminal 302 and the current collector 450 are attached to the sealing plate 130 via an insulating member. After the first electrode body 201 and the second electrode body 202 are inserted into the case body 110, the current collector 450 is brought into contact with the current collector 420 protruding from the opening 114 in the X direction. The plate-shaped member 304 can be connected to the positive electrode terminal 302 at any time.

[0159] like Figure 24 As shown, the positive electrode tab group 250 and the positive electrode tab group 280 connected to the current collector 420 are bent so that the end portions 252 and 282 face each other. Figure 24 From the state shown, the sealing plate 130 is brought into contact with the housing body 110. At this time, by bringing the sealing plate 130 and the main body of the electrode body 200 closer together, the positive electrode tab group 250 and the positive electrode tab group 280 are bent. Figure 12 As shown, the positive electrode tab group 250 and the positive electrode tab group 280 are bent along the shape of the spacer 600 so that the folded-back portions of the bent portions 251 and 281 approach the case body 110 in the Y direction.

[0160] After the sealing plate 130 is brought into contact with the housing body 110, the sealing plate 130 is temporarily welded to the housing body 110. This temporary welding partially joins the sealing plate 130 to the opening 114 of the housing body 110. This positions the sealing plate 130 relative to the housing body 110.

[0161] Figure 25 1 is a perspective view showing the structure of the secondary battery 1. Figure 13 as well as Figure 25 As shown, sealing plates 120 and 130 are then joined to case body 110 (step S10 ). Sealing plate 120 seals opening 113 of case body 110 , while sealing plate 130 seals opening 114 of case body 110 . Thus, first electrode assembly 201 and second electrode assembly 202 are housed in case 100 .

[0162] After the above steps, a leak test and other inspections are performed (step S11). After the leak test, the secondary battery 1 is dried to remove moisture from the housing 100. Then, the electrolyte is injected into the interior of the housing 100 from the injection hole 134. When injecting the electrolyte, the sealing plate 130 is facing upward, the sealing plate 120 is facing downward, the housing 100 is tilted, and the electrolyte is injected into the interior of the housing 100 from the injection hole 134 of the sealing plate 130. Then, exhaust charging is performed. During exhaust charging, the injection hole 134 can also be temporarily sealed. Then, the injection hole 134 is sealed, and the secondary battery 1 is completed.

[0163] The order of the electrode assembly 200 insertion step and the current collector connection step is not limited to the example described above. For example, only a portion of the electrode assembly 200 may be inserted into the case body 110 (first step) so that the end of the negative electrode active material layer 212 (second electrode active material layer) on the opening 113 side is positioned outside the case body 110. The negative electrode terminal 301 (first electrode terminal) provided on the sealing plate 120 (first sealing plate) is then electrically connected to the negative electrode tab group 220 and 270 (first electrode tabs). Subsequently, the electrode assembly 200 may be inserted into the case body 110 until the end of the negative electrode active material layer 212 on the opening 113 side is positioned inside the case body 110 (second step). In other words, the negative electrode terminal 301 and the electrode assembly 200 may be electrically connected during the insertion step of the electrode assembly 200 into the case body 110.

[0164] In this embodiment, by providing the negative tab group 220 and the positive tab group 250 in the first electrode body 201 and providing the negative tab group 270 and the positive tab group 280 in the second electrode body 202 , the first electrode body 201 and the second electrode body 202 can have separate electrode tabs.

[0165] According to this configuration, the first electrode body 201 and the second electrode body 202 form a gathered electrode tab, and the electrode tab can be shortened compared to the case where the electrode tab is bent.

[0166] As a result, the volume occupied by the electrode tabs can be reduced, thereby improving the energy density of the secondary battery 1. Furthermore, in a configuration where the first electrode body 201 and the second electrode body 202 are provided with separate electrode tabs, the electrode tabs are easier to bend than in a configuration where the first electrode body 201 and the second electrode body 202 form a single, integrated electrode tab. This facilitates the joining of the electrode tabs to the current collector, enabling stable secondary battery manufacturing. In particular, the stable manufacturing of the secondary battery 1 improves the reliability of the connection between the electrode tabs and the current collector.

[0167] (Specific Structure of Current Collectors 410 and 430)

[0168] Next, refer to Figures 26 to 28 The specific structures of the current collector 410 (first current collecting member) and the current collector 430 (second current collecting member) will be described. Figure 26 This is a side view showing only the connection structure on the negative electrode side of the sealing plate 120 (first sealing plate). Figure 27 This is a longitudinal sectional view showing only the connection structure on the negative electrode side excluding the negative electrode tab group 220 and 270 and the electrode body 200. Figure 28 It is a perspective view showing a state before the sealing plate 120 is fixed to the housing body 110 .

[0169] The current collector 410 has a plate-like shape and includes a first region R1, a second region R2, and a third region R3. The first region R1 is positioned between the second and third regions R2 and R3. The negative electrode tab group 220 and 270 (first electrode tab) is connected to the first region R1. Preferably, the second region R2, first region R1, and third region R3 are arranged in this order along the longitudinal direction of the sealing plate 120.

[0170] The current collector 430 has a plate-like shape and includes a fourth region R4, a fifth region R5, and a sixth region R6. The fourth region R4 is disposed between the fifth region R5 and the sixth region R6.

[0171] The current collector 410 has the following configuration: in the direction perpendicular to the sealing plate 120 (X direction), the surface of the first region R1 on the sealing plate 120 side protrudes toward the sealing plate 120 side compared to the surface of the second region R2 on the sealing plate 120 side and the surface of the third region R3 on the sealing plate 120 side.

[0172] A first chamfered portion RT2 is provided at the end portion of the second region R2 on the fifth region R5 side, and a second chamfered portion RT5 is provided at the end portion of the fifth region R5 on the second region R2 side.

[0173] In this embodiment, since the entire first region R1 protrudes toward the sealing plate 120, a recess 410p is provided on the negative electrode tab group 220, 270 side of the first region R1. Consequently, the negative electrode tab group 220, 270 is connected to the recess 410p of the first region R1. Alternatively, the negative electrode tab group 220, 270 (first electrode tab) side of the first region R1 may be flat.

[0174] In the direction perpendicular to the sealing plate 120 (X direction), the fourth region R4 of the current collector 430 on the electrode body 200 side has a recessed portion 430 p that is recessed toward the sealing plate 120 compared to the fifth region R5 and the sixth region R6 .

[0175] The length (PL1) of the recessed portion 430p in the longitudinal direction (Z direction) is preferably greater than the length of the portion in the first region R1 protruding toward the sealing plate 120 in the longitudinal direction (Z direction). The length of the portion in the first region R1 protruding toward the sealing plate 120 in the longitudinal direction (Z direction) is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more of the length (PL1) of the recessed portion 430p in the longitudinal direction (Z direction).

[0176] Preferably, the first region of the current collector 410 has a protrusion 410q protruding toward the sealing plate 120 . The protrusion 410q has a distal end surface 410q1 located at the distal end in the protrusion direction and outer side surfaces 410q2 located at both ends in the longitudinal direction of the distal end surface 410q1 .

[0177] The recess 430p preferably has a bottom surface 430p1 and inner side surfaces 430p2 provided at both ends of the bottom surface 430p1 in the longitudinal direction. The distal end surface 410q1 of the protrusion 410q faces, abuts, or is in close proximity to the bottom surface 430p1 of the recess 430p. The longitudinal length (PL11) of the distal end surface 410q1 of the protrusion 410q of the current collector 410 in the longitudinal direction (Z direction) is preferably at least 70%, more preferably at least 80%, and even more preferably at least 90%, of the longitudinal length (PL12) of the bottom surface 430p1 of the recess 430p. Furthermore, it is preferably less than 100%.

[0178] In the recess 430p, the length (PL1) of the recess 430p in the longitudinal direction (Z direction) can be greater than the length (TL1) of the negative electrode tab group 220, 270 (first electrode tab) in the longitudinal direction (Z direction). When the negative electrode tab group 220, 270 (first electrode tab) has a trapezoidal shape, the length (Z direction) of the region of the negative electrode tab group 220, 270 that is connected to the current collector 410 is set to the length (TL1) of the negative electrode tab group 220, 270.

[0179] In addition, refer to Figure 11 The length (PL2) of the concave portion 430p in the short-side direction (Y direction) is preferably greater than the length (TL2) of the portion of the negative electrode tab group 220, 270 (first electrode tab) in the width direction (Y direction) that contacts the current collector 410. Furthermore, the entire short-side region of the current collector 430 preferably constitutes the concave portion 430p.

[0180] When current collector 410 and current collector 430 overlap, it is preferred that at least a portion of first region R1 of current collector 410 be positioned within recess 430p of current collector 430. This allows for proper positioning of current collector 410 relative to current collector 430. Consequently, current collector 410 and current collector 430 can be stably connected.

[0181] Preferably, when the first region R1 is disposed within the recess 430p, a first gap S1 can be provided between the first region R1 and the inner side surface of the recess 430p, on the second region side, and a second gap S2 can be provided on the third region side. The first gap S1 and the second gap S2 can absorb any positional deviation of the first region R1 within the recess 430p, facilitating positioning of the first region R1 relative to the recess 430p. Alternatively, only one of the first gap S1 and the second gap S2 may be provided.

[0182] In addition, in the longitudinal direction of the recess 430p ( Figure 26 In the Z direction), the width of the first gap S1 (the part with the largest width of the gap) and the width of the second gap S2 (the part with the largest width of the gap) are preferably less than 5 mm, more preferably less than 3 mm, and further preferably less than 2 mm.

[0183] In addition, a first contact region TR1 may be formed where the second region R2 of the current collector 410 abuts the fifth region R5 of the current collector 430. Furthermore, a second contact region TR2 may be formed where the corresponding regions abut each other between the first region R1 of the current collector 410 and the fourth region R4 of the current collector 430, and between the third region R3 of the current collector 410 and the sixth region R6 of the current collector 430. This allows the current collector 410 and the current collector 430 to be more stably connected.

[0184] In this embodiment, a second contact region TR2 is formed between the third region R3 and the sixth region R6. This configuration further stabilizes the contact between the current collectors 410 and 430. This prevents contact between the first region R1 and the fourth region R4, effectively suppressing loosening.

[0185] Alternatively, the first region R1 and the fourth region R4, the second region R2 and the fifth region R5, and the third region R3 and the sixth region R6 may all be in contact with each other. This configuration allows positioning to be achieved while suppressing looseness.

[0186] The length of the contact surface of the first contact region TR1 where the second region R2 and the fifth region R5 abut is preferably 1 mm or longer, more preferably 2 mm or longer, and even more preferably 3 mm or longer. Furthermore, the first region R1 and the fourth region R4 may form a proximity region (proximity surface). A proximity region refers to a state where there is no contact but little gap, for example, 0.5 mm or less.

[0187] The end of the first contact region TR1 (the upper end in the figure) is provided with a joint portion SG1, which is joined by welding WD. Providing the first contact region TR1 allows for stable welding of the end of the first contact region TR1. Furthermore, after forming the joint portion SG1, loosening of the first contact region TR1 is suppressed even when a load is applied to the first contact region TR1.

[0188] For welding, it is preferable to use high-energy beam welding, and more preferably laser welding using a laser. In this way, a joint portion SG1 with high joining reliability can be formed. At this time, from the side of the collector 410 and the collector 430 ( Figure 26 When irradiating with high-energy radiation (above the region R2), it is preferable to form a V-shaped receiving portion by the first chamfered portion RT2 at the end of the second region R2 and the second chamfered portion RT5 at the end of the fifth region R5. This facilitates the formation of the joint SG1, which is therefore preferred. Alternatively, it is possible to irradiate one region (the current collector) with high-energy radiation and form the joint SG1 between the second region R2 and the fifth region R5 by penetration welding.

[0189] The process of forming the joint portion SG1 can be performed by irradiating the chamfered portion of at least one of the current collector 410 and the current collector 430 with laser light from between the case body 110 and the sealing plate 120 during the step of joining the current collector 410 and the current collector 430 after the electrode body 200 is inserted into the case body 110. However, the process of forming the joint portion SG1 is not limited to this timing.

[0190] Furthermore, the first gap S1 described above can be provided near the end of the first contact region TR1 opposite to the end where the joint SG1 is formed. Providing the first gap S1 can suppress the heat generated during the formation of the joint SG1 from escaping toward the first region R1 and the fourth region R4, thereby enabling stable formation of the joint SG1.

[0191] In the current collector 430, the thickness (t4) of the fourth region R4 is preferably smaller than the thickness (t5) of the fifth region R5 and the thickness (t6) of the sixth region R6. The ratio of the thickness (t4) of the fourth region R4 to the thickness (t5) of the fifth region R5 is preferably approximately 0.3 to 0.8. The ratio of the thickness (t4) of the fourth region R4 to the thickness (t6) of the sixth region R6 is preferably approximately 0.3 to 0.8. The ratio of the thickness (t1) of the first region R1 to the thickness (t2) of the second region R2 is preferably approximately 0.8 to 1.2. The ratio of the thickness (t1) of the first region R1 to the thickness (t3) of the third region R3 is preferably approximately 0.8 to 1.2. The current collector 410 can be formed by bending a plate material.

[0192] The portion of the current collector 410 connected to the negative electrode tab group 220 , 270 may be positioned closer to the third region R3 than to the second region R2 (the lower side in the figure).

[0193] In the longitudinal direction of the sealing plate 120 , the end of the third region R3 may protrude outward relative to the end of the sixth region R6 (a distance P1 in the figure).

[0194] (Other Implementation Methods)

[0195] Reference Figures 29 to 33 , other forms of the second region R2 of the current collector 410 and the fifth region R5 of the current collector 430 will be described. Figures 29 to 33 These are the first to fifth perspective views showing other aspects of the junction between the second region R2 of the current collector 410 and the fifth region R5 of the current collector 430 .

[0196] Figure 29 The joint portion shown is in the following form: Figure 28 In the illustrated joining configuration, the fifth region R5 of the current collector 430 is positioned separately from the insulating member 530. In this joining configuration, since the joining portion SG1 faces the Z direction, the joining operation between the second region R2 and the fifth region R5 can be facilitated. Furthermore, since the joining portion SG1 is separated from the insulating member 530, damage to the insulating member 530 caused by heat can be suppressed.

[0197] Figure 30The shape of the joint shown has the following shape: the second region R2 of the collector 410 is bent vertically toward the electrode body 200 side, and the fifth region R5 of the collector 430 is also bent vertically toward the electrode body 200 side in a manner along the second region R2. As a result, an overlapping region R11 is provided between the second region R2 and the fifth region R5, and a joint SG1 is formed in this region. According to the shape of the joint, since the joint SG1 is oriented in the Z direction, the joining operation of the second region R2 and the fifth region R5 can be easily performed. In addition, since the joint SG1 is separated from the insulating member 530, damage caused by the influence of heat on the insulating member 530 can be suppressed. In addition, the formation area of the joint SG1 can be increased.

[0198] Figure 31 The illustrated joint has the following configuration: the second region R2 of the current collector 410 is bent so as to protrude toward the electrode body 200, and the fifth region R5 of the current collector 430 is also bent toward the electrode body 200 along the second region R2. As a result, the overlapping region R11 between the second region R2 and the fifth region R5 is arranged at an angle relative to the sealing plate 120, and a joint SG1 is formed in this region R11. Due to this joint configuration, since the joint SG1 is tilted toward the Z direction, the joining operation of the second region R2 and the fifth region R5 can be easily performed. In addition, since the joint SG1 is separated from the insulating member 530, damage to the insulating member 530 caused by the influence of heat can be suppressed.

[0199] Figure 32 The illustrated joint configuration is as follows: the second region R2 of the current collector 410 is arranged to extend in the Z direction closer to the electrode body 200 than the first region R1. The fifth region R5 of the current collector 430 is also arranged to extend in the Z direction along the second region R2. Furthermore, the end of the fifth region R5 is arranged to protrude beyond the end of the second region R2. As a result, the joint SG1 can be formed in the fifth region R5 protruding from the second region R2, making it easier to perform welding from an oblique direction. Furthermore, since the joint SG1 is separated from the insulating member 530, damage to the insulating member 530 caused by heat is suppressed.

[0200] for Figure 33In the illustrated joint configuration, the second region R2 of the current collector 410 is provided with a first extension R21 extending obliquely upward from its end toward the electrode body 200. The fifth region R5 of the current collector 430 is separated from the insulating member 530 so as to be in contact with the second region R2. Furthermore, a second extension R51 is provided at the end of the fifth region R5, which bends toward the insulating member 530. As a result, the first extension R21 and the second extension R51 form a receiving portion with a V-shaped cross-section. By forming the receiving portion in this manner, a joint SG1 can be formed in the receiving portion, facilitating welding operations. In addition, the joint SG1 is separated from the insulating member 530, thereby suppressing damage to the insulating member 530 caused by the influence of heat.

[0201] exist Figures 28 to 33 In the disclosed embodiment, the current collectors 410 and 430 may be connected before the electrode body 200 is inserted into the case body 110 or after at least a portion of the electrode body 200 is inserted into the case body 110 .

[0202] While the above embodiment illustrates the current collection structure on the negative electrode side, the current collection structure described in the above embodiment can also be applied to the current collection structure on the positive electrode side. Furthermore, while the above embodiment illustrates an example of using two current collectors 410 on the negative electrode side, it is also possible to use only one current collector 410, as on the positive electrode side. Furthermore, the current collectors 410 and 430 may be connected before the electrode body 200 is inserted into the case body 110.

[0203] While the embodiments of the present invention have been described, the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, and is intended to encompass all modifications within the meaning and scope of the claims and equivalents.

Claims

1. A secondary battery comprising: an electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode; a housing body having a first opening; a first sealing plate for sealing the first opening; a first electrode tab, the first electrode tab being electrically connected to the first electrode; a first current collecting member electrically connected to the first electrode tab; a second current collecting member joined to the first current collecting member; and a first electrode terminal electrically connected to the second current collecting member and provided on the first sealing plate; in, The first current collecting member includes a first region, a second region, and a third region. The first area is arranged between the second area and the third area. The second current collecting member includes a fourth region, a fifth region, and a sixth region. The fourth area is arranged between the fifth area and the sixth area. The first electrode tab is connected to the first region. In a direction perpendicular to the first sealing plate, a surface of the first region on the first sealing plate side protrudes toward the first sealing plate relative to a surface of the second region on the first sealing plate side and a surface of the third region on the first sealing plate side. The fourth region has a recessed portion on the surface of the second current collecting member facing the electrode body in a direction perpendicular to the first sealing plate, which is recessed toward the first sealing plate relative to the fifth and sixth regions. At least a portion of the first region is disposed within the recess.

2. The secondary battery according to claim 1, wherein A first contact region is formed in which the second region contacts the fifth region. Furthermore, a second contact region in which corresponding regions contact each other is formed between at least one of the first region and the fourth region and between the third region and the sixth region.

3. The secondary battery according to claim 2, wherein A joint portion where the first current collecting member and the second current collecting member are joined is provided at an end portion of the first contact region.

4. The secondary battery according to claim 3, wherein A first gap exists near an end portion of the first contact region opposite to the end portion where the joining portion is formed.

5. The secondary battery according to claim 2, wherein The second contact region is formed between the third region and the sixth region.

6. The secondary battery according to claim 1, wherein The thickness of the fourth region is smaller than the thickness of the fifth region and the thickness of the sixth region.

7. The secondary battery according to claim 1, wherein A portion of the first current collecting member connected to the first electrode tab is located closer to the third region than to the second region.

8. The secondary battery according to claim 1, wherein In the longitudinal direction of the first sealing plate, an end portion of the third region protrudes outward from an end portion of the sixth region.

Images