Secondary battery and method for manufacturing secondary battery

Abstract

The invention provides a secondary battery and a method for manufacturing the secondary battery. In a method for manufacturing a secondary battery (1), a step for joining a first current collector member (420) and a second current collector member (450) includes a step for joining the first current collector member (420) and the second current collector member (450) by irradiating a high-energy line (2) to at least one of the first current collector member (420) and the second current collector member (450) from between a case main body (110) and a first sealing plate (130).

Description

Technical Field The present technology relates to a secondary battery and a method for manufacturing the secondary battery. Background Art Japanese Patent No. 4537353 discloses a square secondary battery in which an electrode group (25) is housed in a casing (14) having openings (14a, 14b) at both ends and electrode terminals (21, 23) are respectively attached to cover plates (33, 33') for sealing the openings (14a, 14b). There is a demand for improved energy density and reliability of secondary batteries. From these viewpoints, there is still room for improvement in the secondary battery described in Japanese Patent No. 4537353. Summary of the invention The present technology aims to provide a secondary battery having high energy density and high reliability, and a method for manufacturing the secondary battery. The present technology provides the following secondary battery and method for manufacturing the secondary battery.

[0001] A method for manufacturing a secondary battery, wherein the secondary battery comprises: an electrode body, the electrode body comprising a first electrode, a second electrode having a polarity different from that of the first electrode, and a first electrode sheet electrically connected to the first electrode; a shell, the shell accommodating the electrode body and comprising a shell body having a first opening, and a first sealing plate for sealing the first opening; a first current collecting component, the first current collecting component being electrically connected to the first electrode sheet; a second current collecting component, the second current collecting component being connected to the first current collecting component; and a first electrode terminal, the first electrode terminal being electrically connected to the second current collecting component and being disposed on the first sealing plate, the two The manufacturing method of the secondary battery comprises the following steps, namely: a step of inserting the above-mentioned electrode body into the above-mentioned shell body; and a step of joining the above-mentioned first current collecting component electrically connected to the above-mentioned first electrode via the above-mentioned first electrode sheet and the above-mentioned second current collecting component electrically connected to the above-mentioned first electrode terminal after the above-mentioned electrode body is inserted into the above-mentioned shell body. The step of joining the above-mentioned first current collecting component and the above-mentioned second current collecting component includes the following steps, namely: irradiating at least one of the above-mentioned first current collecting component and the above-mentioned second current collecting component with high-energy rays from between the above-mentioned shell body and the above-mentioned first sealing plate, thereby joining the above-mentioned first current collecting component and the above-mentioned second current collecting component.

[0002] In the manufacturing method of a secondary battery described in [1], the shell body has a second opening at a position opposite to the first opening, the second opening is sealed by a second sealing plate, a second electrode terminal is provided on the second sealing plate, the first electrode sheet is provided at the end of the electrode body on the side close to the first sealing plate, and a second electrode sheet electrically connected to the second electrode is provided at the end of the electrode body on the side close to the second sealing plate. The manufacturing method of the secondary battery further comprises a step of electrically connecting the second electrode sheet to the second electrode terminal.

[0003] In the method for manufacturing a secondary battery described in [2], before the electrode body is inserted into the case body, the second electrode terminal provided on the second sealing plate is electrically connected to the second electrode sheet.

[0004] In the manufacturing method of a secondary battery described in [2], the second electrode has a second electrode core and a second electrode active material layer formed on the second electrode core, and the step of inserting the electrode body into the shell body includes: a first step of inserting a portion of the electrode body into the shell body, and placing the end of the second electrode active material layer on the second opening side outside the shell body; and a second step of placing the end of the second electrode active material layer on the second opening side inside the shell body after the first step, and electrically connecting the second electrode terminal provided on the second sealing plate to the second electrode sheet after the first step and before the second step.

[0005] In the manufacturing method of a secondary battery recorded in any one of [1] to [4], the above-mentioned first electrode has a first electrode core and a first electrode active material layer formed on the above-mentioned first electrode core, and the above-mentioned first collecting component is joined to the above-mentioned second collecting component in a state in which the end of the above-mentioned first electrode active material layer on the side close to the above-mentioned first opening is arranged inside the above-mentioned shell body.

[0006] In the method for manufacturing a secondary battery described in any one of [1] to [5], the first current collecting member and the second current collecting member are joined in a direction orthogonal to the first sealing plate with a resin member disposed between a position where the high-energy beam is irradiated and the main body of the electrode body.

[0007] In the method for manufacturing a secondary battery according to any one of [1] to [6], the thickness of the second current collecting member is greater than the thickness of the first current collecting member.

[0008] In the method for manufacturing a secondary battery described in any one of [1] to [7], the first current collecting component has a first region extending along the first sealing plate, a second region extending in a direction intersecting the first sealing plate, and a first bent portion provided between the first region and the second region; the second current collecting component has a third region extending along the first sealing plate, a fourth region extending in a direction intersecting the first sealing plate, and a second bent portion provided between the third region and the fourth region; the first region and the third region are arranged to overlap, the first region is located closer to the electrode body than the third region, the first electrode sheet is connected to the first region, and the second region and the fourth region are joined.

[0009] In the method for manufacturing a secondary battery according to any one of [1] to [8], a high-energy beam is irradiated onto a boundary between the first current collecting member and the second current collecting member, wherein the boundary is formed by arranging an end portion of the first current collecting member and an end portion of the second current collecting member in a staggered manner.

[0010] In the method for manufacturing a secondary battery described in any one of [1] to [8], a contact surface formed by the contact between the first current collecting component and the second current collecting component, and a separation portion provided at an end of the contact surface and formed by separating the first current collecting component from the second current collecting component are formed, and high-energy rays are irradiated to the end of the contact surface via the separation portion.

[0011] In the method for manufacturing a secondary battery according to any one of [1] to

[10] , a region of the second current collecting member where a gap is formed with the first sealing plate is irradiated with high energy rays.

[0012] A secondary battery, comprising: an electrode body, the electrode body comprising a first electrode, a second electrode having a polarity different from that of the first electrode, and a first electrode sheet electrically connected to the first electrode; a shell, the shell accommodating the electrode body and comprising a shell body having a first opening, and a first sealing plate for sealing the first opening; a first current collecting component, the first current collecting component being electrically connected to the first electrode sheet; a second current collecting component, the second current collecting component being connected to the first current collecting component; and a first electrode terminal, the first electrode terminal being electrically connected to the second current collecting component and being arranged on the first sealing plate, the secondary battery being formed with a contact surface formed by the contact between the first current collecting component and the second current collecting component, and the first current collecting component and the second current collecting component being joined at the end of the contact surface. The foregoing and other objects, features, aspects 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 Figure 1 It is a front view showing the structure of the secondary battery according to the first embodiment. Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery. Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery. Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery. Figure 5 It means when viewed from the direction of arrow V Figure 1 A diagram showing the state of a secondary battery. Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown. Figure 7 It is a front view showing a negative electrode original plate before forming a negative electrode plate. Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate shown. Fig. 9 It is a front view showing a negative electrode plate formed from a negative electrode original plate. Fig.10 It is a front view showing a positive electrode original plate before forming a positive electrode plate. Fig.11 yes Fig.10 XI-XI cross-sectional view of the positive electrode original plate shown. Fig.12 It is a front view showing a positive electrode plate formed from a positive electrode original plate. Fig.13 yes Figure 1 XIII-XIII cross-sectional view of the secondary battery shown. Fig.14 yes Figure 1 A XIV-XIV cross-sectional view of the secondary battery shown. Fig.15 This is a flowchart showing the method for manufacturing the secondary battery according to the first embodiment. Fig.16 It is a perspective view showing a state before two electrode bodies included in the secondary battery of Embodiment 1 are overlapped. Fig.17 yes Fig.16 XVII-XVII cross-sectional view of the electrode body and the current collector shown. Fig.18 It is a perspective view showing a state where a holder and a separator are attached to an electrode body. Fig.19 It is a perspective view showing a state where a sealing plate is attached to a current collector on the negative electrode side. Fig. 20 yes Fig.19 XX-XX cross-sectional view of the electrode body and the current collector shown. Fig.21 It is a perspective view showing a state where the electrode body is inserted into the case body. Fig. 22 It is a perspective view showing a state where a sealing plate is attached to a current collector on the positive electrode side. Fig.23 yes Fig. 22 XXIII-XXIII cross-sectional view of the electrode body and the current collector shown. Fig.24 It means observing from the direction of arrow XXIV Fig. 22 The diagram shows the state of the current collector. Fig.25 yes Fig.24 XXV-XXV cross-sectional view of the current collector shown. Fig.26 It is a perspective view showing the structure of the secondary battery according to the first embodiment. Fig. 27 It is a cross-sectional view showing the structure of a secondary battery according to the second embodiment. Fig.28 It is a perspective view showing the structure of a current collector included in a secondary battery according to Embodiment 3. Fig.29 yes Fig.28 XXIX-XXIX cross-sectional view of the current collector shown. Fig.30 It is a perspective view showing the structure of a current collector included in a secondary battery according to a fourth embodiment. Fig.31 yes Fig.30 XXXI-XXXI cross-sectional view of the current collector shown. Fig.32 It is a perspective view showing the structure of a current collector included in a secondary battery according to a fifth embodiment. Fig.33 yes Fig.32 XXXIII-XXXIII cross-sectional view of the current collector shown. Fig.34 It is a perspective view showing the structure of a current collector included in a secondary battery according to the sixth embodiment. Fig.35 yes Fig.34 XXXV-XXXV cross-sectional view of the current collector shown. Fig.36It is a cross-sectional view showing the structure of a current collector included in a secondary battery according to a seventh embodiment. DETAILED DESCRIPTION Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and description thereof may not be repeated. In addition, in the embodiments described below, when the number, amount, etc. are mentioned, the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, except for the cases where there are special records, each component is not necessarily essential to the present technology. In addition, the present technology is not necessarily limited to the technology that has all the effects mentioned in the present embodiment. In addition, in this specification, the descriptions of "comprise", "include", and "have" are open forms. That is, when a certain structure is included, other structures other than the structure may or may not be included. In addition, in this specification, when geometrical terms and terms indicating position and direction relationships are used, such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along", etc., these terms allow for manufacturing errors or some changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.). In this specification, "secondary battery" is not limited to lithium-ion batteries, and may include other secondary batteries such as nickel-hydrogen batteries and sodium-ion batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode. In addition, in the drawings, the direction along the winding axis of the electrode body of the secondary battery is set as the X direction, the short side direction of the electrode body when viewed from the X direction is set as the Y direction, and the long side direction of the electrode body when viewed from the X direction is set as the Z direction. In addition, in order to facilitate the understanding of the invention, there are parts in which the dimensions of each structure in the drawings are changed from the actual dimensions. In the present application specification, the first direction (X direction) is sometimes referred to as the “width direction” of the secondary battery or the shell body, the second direction (Y direction) is similarly referred to as the “thickness direction” of the secondary battery or the shell body, and the third direction (Z direction) is similarly referred to as the “height direction” of the secondary battery or the shell body. (Implementation Method 1) Hereinafter, the secondary battery 1 according to the first embodiment will be described. (Overall structure of the battery) Figure 1It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 5 They are respectively 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. The secondary battery 1 can be mounted on an 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-mounted use. like Figure 1 to Figure 6 As shown, the secondary battery 1 includes a case 100 , an electrode body 200 , an electrode terminal 300 , and a current collector 400 . The case 100 includes a case body 110 , a sealing plate 120 , and a sealing plate 130 . When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or the battery pack may be directly supported by the side surface of the battery pack housing without using a constraining member. The case body 110 is formed of a cylindrical, preferably rectangular, member. This provides a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, aluminum alloy, iron, or iron alloy. like Figure 1 , Figure 2 As shown in FIG. 1 , a sealing plate 120 (second wall) and a sealing plate 130 (first wall) are provided at both ends of the housing body. The housing body 110 is formed by, for example, bringing the ends of the plate-like members subjected to bending into contact with each other (at Figure 2 The square tube shape can be formed by joining the two members (for example, laser welding) to each other as shown in the joining portion 115 illustrated in FIG. The corners of the "square tube shape" may also have an R shape. In the present embodiment, the shell body 110 is formed in the width direction (X direction) of the secondary battery 1 to be longer than the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X direction is preferably more than 30 cm. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z direction is preferably less than 20 cm, more preferably less than 15 cm, and further preferably less than 10 cm. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved. The housing 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 housing 100. The pair of second side portions 112 constitute the bottom surface portion and the upper surface portion of the housing 100. The pair of first side portions 111 and the pair of second side portions 112 are arranged to intersect each other. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. The area of ​​each of the pair of first side portions 111 is preferably larger than the area of ​​each of the pair of second side portions 112. like Figure 5 As shown, a second side surface 112A of one of the pair of second side surfaces 112 is provided with an exhaust valve 150. The exhaust valve 150 extends along the width direction (X direction) of the secondary battery 1. The exhaust valve 150 extends from the center of the housing body 110 in the X direction along the X direction to an extent that it does not reach both ends. The exhaust valve 150 can be appropriately changed. The thickness of the plate-shaped member in the exhaust valve 150 is formed thinner than the thickness of the plate-shaped member of the housing body 110 other than the exhaust valve 150. Therefore, when the pressure in the housing 100 becomes equal to or higher than a predetermined value, the exhaust valve 150 breaks preferentially compared to other parts in the housing body 110, thereby exhausting the gas in the housing 100 to the outside. like Figure 2 As shown, a joint portion 115 is formed on the other second side portion 112B of the pair of second side portions 112. The joint portion 115 extends along the width direction (X direction) of the secondary battery 1. In the joint portion 115, the edge sides of the plate-like members constituting the case body 110 are joined to each other. like Figure 3As shown, an opening 113 (second opening) is provided at the end of the first side in the first direction (X direction) of the housing body 110. The opening 113 is sealed by a sealing plate 120. A joint 115 is formed in the opening 113 to seal the opening 113. The opening 113 and the sealing plate 120 have a roughly rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. In addition, the roughly rectangular shape includes a substantially rectangular shape such as a rectangular shape or a shape in which the corners of the rectangular shape are rounded. The sealing plate 120 (second sealing plate) is provided with a negative electrode terminal 301. The position of the negative electrode terminal 301 can be changed as appropriate. like Figure 4 As shown, an opening 114 (first opening) is provided at the end of the second side of the housing body 110 on the side opposite to the first side in the first direction (X direction). That is, the opening 114 is located at the end on the side opposite to the opening 113, and the openings 113 and 114 are opposite to each other. The opening 114 is sealed by the sealing plate 130. A joint 115 is formed in the opening 114 to seal the opening 114. The opening 114 and the sealing plate 130 have a generally rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. The sealing plate 130 (first 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. The sealing plate 120 and the sealing plate 130 are made of metal. Specifically, the sealing plate 120 and the sealing plate 130 are made of aluminum, aluminum alloy, iron, iron alloy, or the like. The negative electrode terminal 301 (second electrode terminal) is electrically connected to the negative electrode of the electrode body 200. The negative electrode terminal 301 is attached to the sealing plate 120, that is, the case 100. The positive electrode terminal 302 (first electrode terminal) is electrically connected to the positive electrode of the electrode body 200 . The positive electrode terminal 302 is attached to the sealing plate 130 , that is, the case 100 . The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301 . The positive electrode terminal 302 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy. 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. The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described later. Specifically, the electrode body 200 is a wound electrode body formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate together via a strip-shaped separator not shown. However, in this specification, the "electrode body" is not limited to a wound electrode body, and may also be a stacked electrode body formed by alternately stacking a plurality of positive plates and a plurality of negative plates. The strip-shaped separator can be composed of a polyolefin microporous film, for example. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets arranged on each positive plate may also be stacked to form a positive electrode sheet group, and the negative electrode sheets arranged on each negative plate may also be stacked to form a negative electrode sheet group. In addition, the electrode body 200 may include a plurality of wound electrode bodies, or may include a plurality of stacked electrode bodies. like Figure 6 As shown, the housing 100 accommodates the electrode body 200. Figure 6 In the embodiment, a first electrode body 201 described later is exemplified. The first electrode body 201 is housed in the case 100 so that its winding axis is parallel to the X direction. Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are housed together inside an insulating sheet 700 to be described later and arranged in the housing 100. As the electrolyte (non-aqueous electrolyte), for example, an electrolyte obtained by dissolving LiPF6 at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio (25° C.) of 30:30:40 can be used. In addition, a solid electrolyte may be used instead of the electrolyte. The first electrode body 201 includes a main body (a portion where a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween), a negative electrode sheet group 220 (a second electrode sheet group), and a positive electrode sheet group 250 (a first electrode sheet group). The main body is composed of a negative electrode plate 210 and a positive electrode plate 240 described later. The negative electrode sheet group 220 is located at the end of the first side of the first electrode body 201 in the first direction (X direction) relative to the main body. The first side in this embodiment is the sealing plate 120 side. The positive electrode sheet group 250 is located at the end of the second side of the first electrode body 201 in the first direction (X direction) relative to the main body. The second side in this embodiment is the sealing plate 130 side. The negative electrode sheet group 220 and the positive electrode sheet group 250 are formed to protrude from the central portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130 . 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-like member. The electrode body 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400 . The negative electrode current collector 400A is arranged on the sealing plate 120 via an insulating member made of resin. The negative electrode current collector 400A is electrically connected to the negative electrode sheet group 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy. In addition, the details of the negative electrode current collector 400A will be described later. The positive electrode collector 400B is arranged on the sealing plate 130 via an insulating member made of resin. The positive electrode collector 400B is electrically connected to the positive electrode sheet group 250 and the positive terminal 302. The positive electrode collector 400B is composed of a conductive material (more specifically, a metal), for example, it can be composed of aluminum or an aluminum alloy. In addition, the positive electrode sheet group 250 can also be electrically connected to the sealing plate 130 directly, or electrically connected to the sealing plate 130 via the positive electrode collector 400B. In this case, the sealing plate 130 can also play the role of the positive terminal 302. In addition, the details of the positive electrode collector 400B will be described later. (Structure of Electrode Body 200) Figure 7 2 is a front view showing a negative electrode original plate 210S before forming the negative electrode plate 210. Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate 210S shown in FIG. Fig. 9 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S. The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. Figure 7 and Figure 8 As shown, the negative electrode original plate 210S includes a negative electrode core 211 (second electrode core) 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 core 211 has a negative electrode active material layer 212 formed thereon except for one end portion of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater. The negative electrode active material layer slurry is prepared by kneading graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium so that the mass ratio of graphite:SBR:CMC is about 98:1:1. The negative electrode core 211 coated with the negative electrode active material layer slurry is dried and the water contained in the negative electrode active material layer slurry is removed to form the negative electrode active material layer 212. Furthermore, the negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing. like Fig. 9 As shown, at one end of the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 230 (second electrode sheets) composed of a negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 230 are stacked to form a negative electrode sheet group 220. Thus, the negative electrode sheet group 220 is connected to the negative electrode plate 210. The positions of the respective plurality of negative electrode sheets 230 and the lengths in the protruding direction are appropriately adjusted in consideration of the connection state between the negative electrode sheet group 220 and the negative electrode collector 400A. In addition, the shape of the negative electrode sheet 230 is not limited to Figure 8 The shape illustrated in . Fig.10 is a front view showing a positive electrode original plate 240S before forming a positive electrode plate 240, Fig.11 yes Fig.10 The XI-XI cross-sectional view of the positive electrode original plate 240S shown in FIG. Fig.12 1 is a front view showing a positive electrode plate 240 formed of a positive electrode original plate 240S. The positive electrode plate 240 as the second electrode has a different polarity from the negative electrode plate 210 as the first electrode. The positive electrode plate 240 is manufactured by processing a positive electrode original plate 240S. Fig.10 and Fig.11 As shown, the positive electrode original plate 240S includes a positive electrode core 241 (first electrode core), 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 core body 241 has a positive electrode active material layer 242 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 242 is formed on the positive electrode core body 241 by applying a positive electrode active material layer slurry using a die coater. The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding material, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium in such a manner that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material becomes approximately 97.5:1:1.5. The positive electrode protection layer 243 is in contact with the positive electrode core 241 and is formed at one end of the positive electrode active material layer 242 in the width direction. The positive electrode protection layer 243 is formed on the positive electrode core 241 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 243 has a resistance greater than that of the positive electrode active material layer 242. The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14. The positive electrode core 241 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried and the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed to form the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, the positive electrode original plate 240S including the positive electrode core 241, the positive electrode active material layer 242 and the positive electrode protective layer 243 is formed by compressing the positive electrode active material layer 242. The positive electrode plate 240 is formed by cutting the positive electrode original plate 240S into a predetermined shape. The positive electrode original plate 240S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing. like Fig.12 As shown, at one end of the width direction of the positive electrode plate 240 formed by the positive electrode original plate 240S, a plurality of positive electrode sheets 260 (first electrode sheets) composed of a positive electrode core 241 are provided. When the positive electrode plate 240 is wound, the plurality of positive electrode sheets 260 are stacked to form a positive electrode sheet group 250. Thus, the positive electrode sheet group 250 is connected to the positive electrode plate 240. The positions of the plurality of positive electrode sheets 260 and the lengths of the protruding directions are appropriately adjusted in consideration of the connection state between the positive electrode sheet group 250 and the positive electrode collector 400B. In addition, the shape of the positive electrode sheet 260 is not limited to Fig.12 The shape illustrated in . A positive electrode protection layer 243 is provided at the root of each of the plurality of positive electrode sheets 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode sheet 260. In a typical example, the thickness of the negative electrode sheet 230 (one sheet) is smaller than the thickness of the positive electrode sheet 260 (one sheet). In this case, the thickness of the first electrode sheet 220 is smaller than the thickness of the second electrode sheet 250. (Connection Structure of Electrode Body 200 and Current Collector 400) Fig.13 yes Figure 1 The XIII-XIII cross-sectional view of the secondary battery shown in FIG. Fig.13As 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 (first electrode) and a negative electrode (second electrode), respectively. Alternatively, the electrode body 200 may be composed of three or more electrode bodies. The electrode body 200 is formed by overlapping 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. The first electrode body 201 includes a negative electrode sheet group 220. The negative electrode sheet 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 sheet group 270. The negative electrode sheet group 270 is electrically connected to a current collector 430 (negative electrode current collector) at a third end 207 in the X direction. The negative electrode sheet group 220 has a bent portion 221 and a front end portion 222. The bent portion 221 is a portion of the negative electrode sheet group 220 bent relative to the front end portion 222 on the side connected to the first electrode. The front end portion 222 is a portion of the negative electrode sheet group 220 located on the side opposite to the side connected to the first electrode. The negative electrode sheet group 270 has a bent portion 271 and a front end portion 272. The bent portion 271 is a portion of the negative electrode sheet group 270 bent relative to the front end portion 272 on the side connected to the first electrode. The front end portion 272 is a portion of the negative electrode sheet group 270 located on the side opposite to the side connected to the first electrode. The negative electrode sheet group 220 and the negative electrode sheet group 270 are bent in opposite directions so that the front ends 222 and 272 approach each other. In this embodiment, the front ends 222 and 272 are separated, but the present invention is not limited to this structure, and the front ends 222 and 272 may also contact each other. The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the negative electrode sheet group 220 and the negative electrode sheet group 270. The negative electrode current collector 400A in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120. The negative electrode current collector 400A includes a current collector 410 , a current collector 430 (third current collecting member), and a current collector 440 (fourth current collecting member). The current collector 410 is a plate-shaped component. The current collector 410 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 430 is a plate-shaped component. The current collector 430 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 410 and the current collector 430 are arranged side by side in the Y direction. In this way, the current collector 410 and the current collector 430 are composed of independent components. The negative electrode sheet group 220 is joined to the collector 410 at a joining portion 411 described later. The negative electrode sheet group 270 is joined to the collector 430 at a joining portion 431 described later. The joining portions 411 and 431 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the negative electrode sheet group 220 and the collector 410, and the negative electrode sheet group 270 and the collector 430 are joined, for example, by ultrasonic bonding. The current collector 440 is joined to the current collector 410 and the current collector 430 at a joint portion (not shown) located at an end in the Z direction. The current collector 440 is connected to the negative electrode terminal 301. The connection between the current collector 440 and the negative electrode terminal 301 can be formed by caulking and / or welding, for example. The negative electrode terminal 301 is provided so as to be exposed outside the sealing plate 120 and reach the current collector 440 of the negative electrode current collector 400A provided on the inner surface side of the sealing plate 120 . The negative electrode terminal 301 is connected to the plate-like member 303 . The plate-like member 303 is located outside the sealing plate 120. The plate-like member 303 is arranged along the sealing plate 120. The plate-like member 303 has conductivity. The plate-like member 303 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the negative terminal 301 and the plate-like member 303 can be formed by, for example, laser welding or the like. An insulating member 510 is disposed between the plate-like 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 440 and the sealing plate 120 . However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120 . In addition, the sealing plate 120 may also play the role of the negative electrode terminal 301 . A separator 600 is disposed between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode sheet group 220). The separator 600 is composed of an insulating resin member. The separator 600 includes a first member 610 and a second member 620. The first member 610 and the second member 620 are engaged with each other at the joints (not shown) at both ends in the Z direction. The end portions of the first member 610 and the second member 620 on the electrode body 200 side in the X direction protrude in the Y direction. Thus, the spacer 600 plays a guiding role when the bent portions 221 and 271 are bent, so that the bent portions 221 and 271 are easily bent. An insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110. The insulating sheet 700 may be made of resin, for example. More specifically, the material of the insulating sheet 700 may be polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO). Fig.14 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 parts corresponding to the current collectors 410 and 430 on the negative electrode side are composed of one member. The first electrode body 201 includes a positive electrode sheet group 250. The positive electrode sheet 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 sheet group 280. The positive electrode sheet group 280 is electrically connected to the current collector 420 (positive electrode current collector) at the fourth end 208 in the X direction. The positive electrode sheet group 250 has a bent portion 251 and a front end portion 252. The bent portion 251 is a portion of the positive electrode sheet group 250 bent relative to the front end portion 252 on the side connected to the second electrode. The front end portion 252 is a portion of the positive electrode sheet group 250 located at the end opposite to the side connected to the second electrode. The positive electrode sheet group 280 has a bent portion 281 and a front end portion 282. The bent portion 281 is a portion of the positive electrode sheet group 280 bent on the side connected to the second electrode relative to the front end portion 282. The front end portion 282 is a portion of the positive electrode sheet group 280 located on the side opposite to the side connected to the second electrode. The positive electrode sheet group 250 and the positive electrode sheet group 280 are bent in opposite directions so that the front ends 252 and 282 approach each other. In addition, in this embodiment, the front ends 252 and 282 are separated, but the present invention is not limited to this structure, and the front ends 252 and 282 may also contact each other. The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the positive electrode sheet group 250 and the positive electrode sheet group 280. The positive electrode current collector 400B in this embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130. The positive electrode current collector 400B includes a current collector 420 (first current collecting member) and a current collector 450 (second current collecting member). The current collector 420 is a plate-shaped member. The current collector 420 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 420 is composed of a single integral member. The positive electrode sheet group 250 and the positive electrode sheet group 280 are joined to the collector 420 composed of one component at a joining portion 421 described later. The joining portion 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the positive electrode sheet group 250 and the positive electrode sheet group 280 are joined to the collector 420, for example, by ultrasonic bonding. The current collector 450 is joined to the current collector 420 at a joining portion (not shown) located at an end in the Z direction. The current collector 450 is connected to the positive electrode terminal 302. The connection between the current collector 450 and the positive electrode terminal 302 can be formed by caulking and / or welding, for example. The positive electrode terminal 302 is provided so as to be exposed outside the sealing plate 130 and reach the current collector 450 of the positive electrode current collector 400B provided on the inner surface side of the sealing plate 130 . The positive electrode terminal 302 is connected to the plate-like member 304 . The plate-like member 304 is located outside the sealing plate 130. The plate-like member 304 is arranged along the sealing plate 130. The plate-like member 304 has conductivity. The plate-like member 304 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the positive terminal 302 and the plate-like member 304 can be formed by, for example, laser welding or the like. 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 530 is disposed between the current collector 450 and the sealing plate 130 . However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130 . In addition, the sealing plate 130 may also play the role of the positive electrode terminal 302 . A separator 600 is disposed between the sealing plate 130 and the main body of the electrode body 200 (excluding the positive electrode sheet group 250, 280). The separator 600 is composed of an insulating resin member. The separator 600 includes a first member 610 and a second member 620. The first member 610 and the second member 620 are engaged with each other at the engaging portions (not shown) at both ends in the Z direction. The end portions of the first member 610 and the second member 620 on the electrode body 200 side in the X direction protrude in the Y direction. Thus, the spacer 600 plays a guiding role when the bent portions 251 and 281 are bent, so that the bent portions 251 and 281 are easily bent. An insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 . (Manufacturing process of secondary battery 1) Hereinafter, a method for manufacturing the secondary battery according to the present embodiment will be described. Fig.15 This is a flowchart showing the method for manufacturing the secondary battery according to the first embodiment. Fig.16 It is a perspective view showing a state before two electrode bodies included in the secondary battery of Embodiment 1 are overlapped. Fig.17 yes Fig.16 XVII-XVII cross-sectional view of the electrode body and the current collector shown. like Fig.15 As shown, in the manufacturing method of the secondary battery of this embodiment, first, the first electrode body 201 and the second electrode body 202 are manufactured (S1 process). For each of the negative electrode sheet group 220, the positive electrode sheet group 250, the negative electrode sheet group 270 and the positive electrode sheet group 280, a part of the front end is cut off so that the length of the front end becomes the same length when bundled. like Figure 15 to Figure 17 As shown, after the first electrode body 201 and the second electrode body 202 are manufactured, the negative electrode sheet group 220 is joined to the current collector 410 (step S2). The negative electrode sheet group 220 is joined to the current collector 410 at the joining portion 411. Next, the negative electrode sheet group 270 is joined to the current collector 430 (step S3). The negative electrode sheet group 270 is joined to the current collector 430 at the joining portion 431. Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged in the first direction (DR1 direction) in sequence. The positive electrode sheet group 250 is arranged on one side of the current collector 420 in the first direction (DR1 direction). With the positive electrode sheet group 280 arranged on the other side of the current collector 420 in the first direction (DR1 direction), the positive electrode sheet group 250 and the positive electrode sheet group 280 are joined to the current collector 420 (S4 process). The positive electrode sheet group 250 and the positive electrode sheet group 280 are joined to the current collector 420 at the joining portion 421. The current collectors 410, 420 and 430 are arranged offset to one side of 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. Thus, the current collectors can be made shorter and smaller. In addition, the current collector 410, the current collector 420, and the current collector 430 are not limited to this structure. The current collector 410, the current collector 420, and the current collector 430 may also 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, in the height direction of the first electrode body 201 and the second electrode body 202, in coordination with the current collector 410, the current collector 420, and the current collector 430, the negative electrode sheet group 220, the positive electrode sheet group 250, the negative electrode sheet group 270, and the positive electrode sheet group 280 are each arranged at the center of the first electrode body 201 and the second electrode body 202. In addition, the order of the steps of joining the collector 410, the collector 420, and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above, and the order may be changed. The step of joining the collector 410 and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is preferably performed before the step of overlapping the first electrode body 201 and the second electrode body 202 described later, and is preferably performed before the step of joining the collector 420 to the first electrode body 201 and the second electrode body 202. Next, after the positive electrode sheet group 250 and the positive electrode sheet group 280 are bonded to the current collector 420, the first electrode body 201 and the second electrode body 202 are bonded in the thickness direction (in the same direction as the thickness of the first electrode body 201 and the second electrode body 202). Fig.16 and Fig.17 The positive electrode sheet group 250 and the positive electrode sheet group 280 are bent in a direction perpendicular to the DR1 direction of the electrode body 200, so that the first electrode body 201 and the second electrode body 202 are overlapped (step S5). That is, the first electrode body 201 and the second electrode body 202 are gathered together. The so-called "overlapping the first electrode body and the second electrode body" means that the first electrode body and the second electrode body can be directly overlapped, or other components can be arranged between the first electrode body and the second electrode body. In addition, the first electrode body and the second electrode body can be fixed by tape or the like, or they can be not fixed. Furthermore, the first electrode body, the current collector, and the second electrode body can also be arranged in a straight line in the first direction (DR1 direction), and the first electrode body or the second electrode body can also be inclined relative to the first direction (DR1 direction) relative to the current collector. The positive electrode sheet group 250 and the positive electrode sheet group 280 are folded so that their front ends face each other. Also, the negative electrode sheet group 220 and the negative electrode sheet group 270 are folded so that their front ends face each other. Fig.18 1 is a perspective view showing a state where a retainer and a separator are installed on an electrode body. Fig.18 As shown, next, the separator 600 and the insulating sheet 700 are assembled to the electrode body 200 (step S6 ). In addition, the insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers an area of ​​50% or more of the outer surface of the electrode body, and more preferably covers an area of ​​70% or more. The insulating sheet 700 preferably covers the entirety of at least four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, excluding the two surfaces on which the negative electrode sheet group 220 and the positive electrode sheet group 250 are formed. Fig.19 It is a perspective view showing a state where a sealing plate 120 is attached to a current collector on the negative electrode side. Fig. 20 yes Fig.19XX-XX cross-sectional view of the electrode body and the current collector shown. like Fig.15 , Fig.19 and Fig. 20 As shown, after the negative electrode sheet group 220 is joined to the current collector 410, the negative electrode sheet group 270 is joined to the current collector 430, and the first electrode body 201 and the second electrode body 202 are overlapped, the current collector 410 and the current collector 430 are electrically connected to the negative electrode terminal 301 via the current collector 440 (step S7). Alternatively, the step S7 may be performed before the step S6. Specifically, the negative electrode sheet group 220 and the negative electrode sheet group 270 are bent so that the front end portions 222 and 272 face each other. The negative terminal 301 and the current collector 440 are mounted on the sealing plate 120 via the insulating member. The current collector 440 is brought into contact with the current collector 410 and the current collector 430 in the X direction. In addition, the plate-shaped member 303 may be connected to the negative terminal 301 at any time. The current collector 440 is joined to the current collector 410 and the current collector 430 by laser welding between the sealing plate 120 and the insulating sheet 700. Fig.21 2 is a perspective view showing a state where an electrode body is inserted into a shell body. Fig.15 and Fig.21 As shown, after the first electrode body 201 and the second electrode body 202 are overlapped, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 from the opening 113 with the current collector 420 at the leading end (step S8 ). The negative electrode sheet group 220 and the negative electrode sheet group 270 are bent 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) close to each other. In addition, it is preferred that the sealing plate 120 and the case body 110 are brought close to each other by bringing the sealing plate 120 and the main body of the electrode body 200 disposed in the case body 110 close to each other. Fig.13 As shown, the negative electrode sheet group 220 and the negative electrode sheet 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. 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. When inserting the electrode body 200 into the case body 110, the electrode body 200 may be pulled from the current collector 420 side or pressed from the current collectors 410 and 430 sides. When the electrode body 200 is pressed from the current collectors 410 and 430 sides, the negative electrode sheet group 220 and the negative electrode sheet group 270 may be bent at the same time. Fig. 22 It is a perspective view showing a state where a sealing plate 130 is attached to a current collector on the positive electrode side. Fig.23 yes Fig. 22 XXIII-XXIII cross-sectional view of the electrode body and the current collector shown. Fig.24 It means observing from the direction of arrow XXIV Fig. 22 The diagram shows the state of the current collector. Fig.25 yes Fig.24 XXV-XXV cross-sectional view of the current collector shown in FIG. Fig.23 , the housing body 110 is omitted. like Fig.15 and Figure 22 to Figure 25 As 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 ). Specifically, the positive terminal 302 and the current collector 450 are mounted on the sealing plate 130 via the 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. In addition, the plate-shaped member 304 may be connected to the positive terminal 302 at any time. like Fig.25 As shown, the current collector 420 (first current collector component) has a first region 10 extending along the sealing plate 130, a second region 20 extending in a direction perpendicular to the sealing plate 130, and an intermediate portion 15 (first bent portion) located between the first region 10 and the second region 20. The current collector 450 (second current collector component) has a third region 30 extending along the sealing plate 130, a fourth region 40 extending in a direction perpendicular to the sealing plate 130, and an intermediate portion 35 (second bent portion) located between the third region 30 and the fourth region 40. The second region 20 and the fourth region 40 extend from the ends of the first region 10 and the third region 30 toward the electrode body 200. exist Fig.25In the example, in the middle portions 15 and 35, the current collectors 420 and 450 are each bent at an approximately right angle. However, the bending angle of the current collectors 420 and 450 is not limited to 90°. A bending angle of 45° or more and 135° or less can be appropriately adopted. In addition, cutouts can be provided at both ends of the bent portion of the current collectors 420 and 450 in the width direction (Y direction) to facilitate bending processing. The bent processed portion may include an R processed portion. The first region 10 of the current collector 420 and the third region 30 of the current collector 450 are arranged to overlap each other. The first region 10 is located closer to the electrode body 200 than the third region 30. The first region 10 of the current collector 420 is connected to the positive electrode sheet groups 250 and 280. The first region 10 and the third region 30 may overlap when viewed from the X direction, and do not necessarily need to abut against each other. However, the first region 10 and the third region 30 are preferably arranged close to each other to a certain extent, for example, the gap between them is preferably 5.0 mm or less, more preferably 3.0 mm or less, and further preferably 1.0 mm or less. When viewed from the X direction orthogonal to the sealing plate 130, the area of ​​the overlapping portion between the first region 10 and the third region 30 is preferably 100 mm. 2 When viewed from the X direction, the area of ​​the third region 30 may be formed larger than the area of ​​the first region 10. Here, the area of ​​the overlapping portion of the first region 10 and the third region 30 is preferably 50% or more of the area of ​​the third region 30, and more preferably 70% or more. In addition, an insulating member may be provided between the first region 10 and the third region 30. The insulating member provided between the first region 10 and the third region 30 may be composed of, for example, an insulating tape or a resin plate. A fuse portion consisting of a through hole, a thin wall portion (groove portion), or a cutout may be formed in the current collector 420 or the current collector 450. Thus, when an external short circuit occurs, the fuse portion melts and the current can be cut off. In addition, the fuse portion may be provided in any of the first region 10, the second region 20, the third region 30, and the fourth region 40. The second region 20 of the current collector 420 and the fourth region 40 of the current collector 450 are arranged to overlap each other. Thus, a contact region R11 is formed where the current collector 420 and the current collector 450 overlap each other. When the current collector 420 and the current collector 450 are connected, the high energy beam 2 is irradiated to at least one of the current collector 420 and the current collector 450 located in the contact region R11 from between the sealing plate 130 and the end of the case body 110 on the opening 114 side. In addition, the high energy beam 2 is irradiated to at least one of the current collector 440 and the current collector 450 from between the sealing plate 130 and the end of the case body 110 on the opening 114 side. The high energy beam 2 is, for example, laser. As a result, the current collector 420 and the current collector 450 are welded and connected at the welding position P1 of the contact region R11. In one example, when the current collector 420 and the current collector 450 are joined, the end portion of the positive electrode active material layer 242 (first electrode active material layer) on the opening 114 side is disposed inside the case body 110 . The welding method of the current collector 420 and the current collector 450 is, for example, penetration welding. The current collector 450 may be provided with a thin wall portion and the current collectors may be welded at the thin wall portion, or the current collector 450 may be provided with a through hole and the current collectors may be welded at a position away from the through hole. In the present embodiment, the contact region R11 is formed to extend along the X-Y plane direction. Therefore, the high-energy line 2 for joining the current collector 420 and the current collector 450 can be irradiated from a direction parallel to the Z direction. As a result, it is possible to configure the high-energy line 2 to be unlikely to interfere with the case body 110 or the sealing plate 130. In addition, the connection between the current collectors on the sealing plate 120 side (negative electrode side) can also be configured in the same manner as the connection between the current collectors on the sealing plate 130 side (positive electrode side). In addition, the current collector 420 on the sealing plate 130 side (positive electrode side) can also be configured by being divided into a plurality of (two) parts, like the current collectors 410 and 430 on the sealing plate 120 side (negative electrode side). like Fig.23 As shown, the positive electrode sheet group 250 and the positive electrode sheet group 280 connected to the current collector 420 are bent so that the front end portions 252 and 282 face each other. Figure 23 to Figure 25 In the state shown, the sealing plate 130 is in contact with the housing body 110. At this time, the positive electrode sheet group 250 and the positive electrode sheet group 280 are bent by bringing the sealing plate 130 and the main body of the electrode body 200 close to each other. Fig.14 As shown, the positive electrode sheet group 250 and the positive electrode sheet group 280 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 251 and 281 approach the case body 110 in the Y direction. 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. By temporarily joining, the sealing plate 130 is partially joined to the opening 114 of the housing body 110. Thus, the sealing plate 130 is positioned relative to the housing body 110. Fig.26 1 is a perspective view showing the structure of a secondary battery according to Embodiment 1. Fig.15 and Fig.26 As shown, next, the sealing plate 120 and the sealing plate 130 are joined to the housing body 110 (step S10). The sealing plate 120 seals the opening 113 of the housing body 110, and the sealing plate 130 seals the opening 114 of the housing body 110. Thus, the first electrode body 201 and the second electrode body 202 are accommodated in the housing 100. After the above steps, a leakage check and other inspections are performed (S11 step). After the leakage check, the secondary battery 1 is dried to remove moisture from the shell 100. Then, the electrolyte is injected into the shell 100 from the injection hole 134. When injecting the electrolyte, the sealing plate 130 is located at the top and the sealing plate 120 is located at the bottom, so that the shell 100 is tilted, and the electrolyte is injected into the shell 100 from the injection hole 134 of the sealing plate 130. After that, exhaust charging is performed. During exhaust charging, the injection hole 134 can also be temporarily sealed. After that, the injection hole 134 is sealed, and the secondary battery 1 is completed. In addition, the order of the insertion process of the electrode body 200 and the connection process of the current collectors is not limited to the above example. For example, after only a portion of the electrode body 200 is inserted into the shell body 110 so that the end of the opening 113 side in the negative electrode active material layer 212 (the second electrode active material layer) becomes a state arranged outside the shell body 110 (the first process), the negative terminal 301 (the second electrode terminal) provided on the sealing plate 120 (the second sealing plate) is electrically connected to the negative electrode sheet group 220, 270 (the second electrode sheet), and then the electrode body 200 is further inserted into the shell body 110 until the end of the opening 113 side in the negative electrode active material layer 212 becomes a state arranged inside the shell body 110 (the second process). That is, the negative terminal 301 can be electrically connected to the electrode body 200 in the middle of the insertion process of inserting the electrode body 200 into the shell body 110. In this embodiment, by providing the negative electrode sheet group 220 and the positive electrode sheet group 250 in the first electrode body 201, and providing the negative electrode sheet group 270 and the positive electrode sheet group 280 in the second electrode body 202, it is possible to form a structure in which the first electrode body 201 and the second electrode body 202 have independent electrode sheets. With this structure, the electrode sheet can be shortened compared with the case where the first electrode body 201 and the second electrode body 202 form an integral electrode sheet and the electrode sheet is bent. As a result, the volume occupied by the electrode sheet can be reduced, so the energy density of the secondary battery 1 can be improved. In addition, in the structure in which the first electrode body 201 and the second electrode body 202 are provided with independent electrode sheets, the electrode sheet is easy to bend compared with the case in which the first electrode body 201 and the second electrode body 202 form an integral electrode sheet, so it is easy to join the electrode sheet with the collector, and the secondary battery can be stably manufactured. In particular, by being able to stably manufacture the secondary battery 1, the reliability of the connection between the electrode sheet and the collector can be improved. In this embodiment, by providing the contact region R11, the weldable region of the collectors can be ensured, so that the collectors can be stably connected to each other. When the collectors are connected to each other by irradiating the high energy line 2 from between the opening 114 of the housing body 110 and the sealing plate 130, the weldable range of the collectors can be easily ensured for irradiation of the high energy line 2 from the second direction (Z direction) intersecting the first direction in which the openings 113 and 114 are arranged. Furthermore, by irradiating at least one of the current collector 420 and the current collector 450 with high-energy line 2 from between the sealing plate 130 and the end on the opening 114 side of the shell body 110, the current collector 420 and the current collector 450 are welded, and after the electrode body 200 is inserted into the shell body 110, the current collectors on the opening 114 side can be stably connected to each other. In the present embodiment, a separator 600 (resin member) is disposed between the welding position P1 where the high-energy beam 2 is irradiated and the main body of the electrode body 200 in the X direction orthogonal to the sealing plate 130. Therefore, it is possible to suppress the reflection of the laser or the metal sputtering from contacting the electrode body 200 when the current collectors 420 and 450 are joined, and the electrode body 200 can be effectively protected. Secondary batteries according to Embodiments 2 to 7 are described below. Regarding the secondary batteries according to Embodiments 2 to 7, description of the same structure as the secondary battery 1 according to Embodiment 1 and the same structure between Embodiments 2 to 7 will not be repeated. In Embodiments 2 to 7, the connection between the current collectors on the sealing plate 130 side is described, but the connection between the current collectors on the sealing plate 120 side may be configured similarly to the connection between the current collectors on the sealing plate 130 side. (Implementation Method 2) Fig. 27 2 is a cross-sectional view showing the structure of a secondary battery according to Embodiment 2. Fig. 27 As shown, in the secondary battery of the second embodiment, the front end portions 222A and 272A of the negative electrode sheet group 220A and the negative electrode sheet group 270A are bent in the same direction in the Y direction. After that, the first electrode body 201A and the second electrode body 202A are inserted into the housing body, and the sealing plate 120 is brought into contact with the housing body. As a result, the negative electrode sheet group 220A and the negative electrode sheet group 270A are bent in the same direction with the front end portions 222A and 272A facing the same direction, respectively. In order to make it easier for the front end portions 222A and 272A to bend in the same direction, the third component 630A of the separator 600A is provided between the negative electrode sheet group 220A and the negative electrode sheet group 270A. By bending the front end portions 222A and 272A of the negative electrode sheet group 220A and the negative electrode sheet group 270A in the same direction in the Y direction, the first electrode body 201 on which the current collector 410 is mounted and the second electrode body 202 on which the current collector 430 is mounted can be prepared with the same structure. Thus, the first electrode body 201 on which the current collector 410 is mounted and the second electrode body 202 on which the current collector 430 is mounted can be configured as one type, so that the manufacturing process can be simplified. (Implementation method 3) Fig.28 It is a perspective view showing the structure of a current collector included in a secondary battery according to Embodiment 3. Fig.29 yes Fig.28 XXIX-XXIX cross-sectional view of the current collector shown. like Fig.29 As shown, the current collector 420B (first current collector component) has a first region 10B extending along the sealing plate 130, a second region 20B extending in a direction intersecting the sealing plate 130, and an intermediate portion 15B (first bent portion) located between the first region 10B and the second region 20B. The current collector 450B (second current collector component) has a third region 30B extending along the sealing plate 130, a fourth region 40B extending in a direction intersecting the sealing plate 130, and an intermediate portion 35B (second bent portion) located between the third region 30B and the fourth region 40B. The first region 10B of the current collector 420B overlaps with the third region 30B of the current collector 450B. The first region 10B is located closer to the electrode body 200 than the third region 30B. The first region 10B of the current collector 420B is connected to the positive electrode sheet groups 250 and 280 . The second region 20B of the current collector 420B and the fourth region 40B of the current collector 450B have a substantially L-shape. The second region 20B and the fourth region 40B are folded back to be inclined from the YZ plane and to have a convex shape toward the case body 110 . The second region 20B constitutes a first protruding region that protrudes toward the electrode body 200 more than the first region 10B, and the fourth region 40B constitutes a second protruding region that protrudes toward the electrode body 200 more than the third region 30B. The second region 20B and the fourth region 40B are arranged to overlap, thereby forming a contact region R31 where the current collector 420B and the current collector 450B overlap each other. An end portion (front end portion) of the fourth region 40B (second protruding region) on the side away from the third region 30B is in contact with the insulating member 530 . Preferably, in the first region 10B and the third region 30B, there is a gap G1 between the current collector 420B and the current collector 450B. As a result, it is easy for the current collectors to preferentially contact each other in the contact region R31. In addition, the reaction force generated by the bending of the electrode sheet acts on the current collector 420B, so that the current collector 420B and the current collector 450B can be closely attached. The size of the gap G1 (X direction) is preferably less than 2.0 mm, and more preferably less than 1.0 mm. In this embodiment, by providing the contact region R31, the weldable region of the collectors can be ensured, so that the collectors can be stably connected to each other. When the collectors are connected to each other by irradiating the high energy line 2 from between the opening 114 of the housing body 110 and the sealing plate 130, the weldable range of the collectors can be easily ensured for irradiation of the high energy line 2 from a direction intersecting the first direction in which the openings 113 and 114 are arranged. (Implementation 4) Fig.30 It is a perspective view showing the structure of a current collector included in a secondary battery according to a fourth embodiment. Fig.31 yes Fig.30 XXXI-XXXI cross-sectional view of the current collector shown. like Fig.31 As shown, the current collector 420C (first current collector component) has a first region 10C and a second region 20C extending along the sealing plate 130, and an intermediate portion 15C located between the first region 10C and the second region 20C. The current collector 450C (second current collector component) has a third region 30C and a fourth region 40C extending along the sealing plate 130, and an intermediate portion 35C located between the third region 30C and the fourth region 40C. In the first region 10C of the current collector 420C and the fourth region 40C of the current collector 450C, a contact region R41 is formed where the current collector 420C and the current collector 450C contact each other in the first direction (X direction). The ends of the current collector 420C and the current collector 450C are arranged to be offset in the Z direction, and the boundary portion is irradiated with the high-energy beam 2 to form a welding position P1. That is, the current collector 420C and the current collector 450C are welded to each other at the ends of the contact region R41. The contact region R41 includes the contact surface between the current collector 420C and the current collector 450C. The contact region R41 extends on a surface intersecting the first direction (X direction). The contact region R41 extends along the Y direction and the Z direction. The contact region R41 is preferably arranged along the sealing plate 130 . In the fourth region 40C, a gap G2 exists between the current collector 450C and the insulating member 530 . This increases the distance between the current collector 450C and the insulating member 530 , making it difficult for heat to be transferred to the insulating member 530 when the current collectors are joined together by the high-energy wire 2 . The size of the gap G2 (in the X direction) is preferably, for example, 0.1 mm or more, more preferably 0.5 mm or more, and further preferably 1.0 mm or more. The size of the gap G2 (in the X direction) is preferably, for example, 5.0 mm or less, more preferably 2.0 mm or less, and further preferably 1.0 mm or less. In this embodiment, by providing the contact region R41, a region where the collectors can be joined can be ensured, thereby facilitating stable connection of the collectors. In particular, the joining portion of the collectors can be ensured without requiring high precision in positioning the collectors to be joined. Furthermore, since the portion where the ends of the current collector 420C and the current collector 450C are offset in the Z direction is used as the welding position P1, the space occupied by the current collector in the X direction can be reduced, thereby improving the energy density of the secondary battery 1. (Implementation 5) Fig.32 It is a perspective view showing the structure of a current collector included in a secondary battery according to a fifth embodiment. Fig.33 yes Fig.32 XXXIII-XXXIII cross-sectional view of the current collector shown. like Fig.33As shown, the current collector 420D (first current collector component) has a first region 10D and a second region 20D extending along the sealing plate 130, and an intermediate portion 15D located between the first region 10D and the second region 20D. The current collector 450D (second current collector component) has a third region 30D and a fourth region 40D extending along the sealing plate 130, and an intermediate portion 35D located between the third region 30D and the fourth region 40D. In the second region 20D of the current collector 420D and the fourth region 40D of the current collector 450D, a contact region R51 is formed where the current collector 420D and the current collector 450D contact each other in the first direction (X direction). At the end of the contact region R51, the current collector 420D and the current collector 450D are bent in a direction away from each other. The high energy beam 2 is irradiated to the end of the contact region R51 through the separation portion, thereby forming a welding position P1. That is, at the end of the contact region R51, the current collector 420D and the current collector 450D are welded and connected. Fig.33 In the structure, it is difficult to produce welding edge collapse. The contact region R51 includes the contact surface between the current collector 420D and the current collector 450D. The contact region R51 extends on the surface intersecting the first direction (X direction). The contact region R51 extends along the Y direction and the Z direction. The contact region R51 is preferably arranged along the sealing plate 130 . In the fourth region 40D, a gap G2 exists between the current collector 450D and the insulating member 530 . This increases the distance between the current collector 450D and the insulating member 530 , making it difficult for heat to be transferred to the insulating member 530 when the current collectors are joined together by the high-energy wire 2 . (Implementation method 6) Fig.34 It is a perspective view showing the structure of a current collector included in a secondary battery according to the sixth embodiment. Fig.35 yes Fig.34 XXXV-XXXV cross-sectional view of the current collector shown. like Fig.35 As shown, the thickness of the collector 450E in the present embodiment in the X direction is thicker than the thickness of the collector 420E in the X direction. Thus, since the allowable amount of heat when the collectors are joined together by the high-energy wire 2 can be ensured in the collector 450E, the heat when the collectors are joined together by the high-energy wire can be difficult to be transferred to the insulating member 530. For example, the thickness of the collector 450E is preferably 1.2 times or more of the thickness of the collector 420E, more preferably 1.5 times or more, and further preferably 2.0 times or more. In addition, for comparison of the thickness of each collector, it is preferred to compare the thickness of the base (the portion of the usual thickness without the concave-convex) of each collector. The current collector 420E is provided with a fuse portion 422E. When the current collector generates excessive heat, the current collector preferentially melts at the fuse portion 422E in the positive electrode current collector which is as far away from the insulating member as possible. In this embodiment, as in Embodiment 5, a separation portion is formed at the end of the contact region R61 where the current collector 420E and the current collector 450E are separated. The high-energy beam 2 is irradiated to the end of the contact region R61 through the separation portion, thereby forming a welding position P1. That is, the current collector 420E and the current collector 450E are welded and connected at the end of the contact region R61. (Implementation 7) Fig.36 It is a cross-sectional view showing the structure of a current collector included in a secondary battery according to a seventh embodiment. like Fig.36 As shown, the current collector 420F (first current collector component) has a first region 10F extending along the sealing plate 130, a second region 20F, and an intermediate portion 15F located between the first region 10F and the second region 20F. The current collector 450F (second current collector component) has a third region 30F extending along the sealing plate 130, a fourth region 40F, and an intermediate portion 35F located between the third region 30F and the fourth region 40F. In the second region 20F of the current collector 420F and the fourth region 40F of the current collector 450F, a contact region R71 is formed where the current collector 420F and the current collector 450F contact each other in the first direction (X direction). In addition, the thickness of the current collector 450F is greater than the thickness of the current collector 420F. In addition, for the comparison of the thickness of each current collector, it is preferable to compare the thickness of the base (the portion of the normal thickness where the concavo-convex is not formed) of each current collector. In this embodiment, as in Embodiments 5 and 6, a separation portion is formed at the end of the contact region R71 where the current collector 420F and the current collector 450F are separated. The high-energy beam 2 is irradiated to the end of the contact region R71 through the separation portion, thereby forming a welding position P1. That is, the current collector 420F and the current collector 450F are welded and connected at the end of the contact region R71. The contact region R71 includes the contact surface between the current collector 420F and the current collector 450F. The contact region R71 extends on the surface intersecting the first direction (X direction). The contact region R71 extends along the Y direction and the Z direction. The contact region R71 is preferably arranged along the sealing plate 130 . In the fourth region 40F, a gap G2 exists between the current collector 450F and the insulating member 530 . This increases the distance between the current collector 450F and the insulating member 530 , making it difficult for heat to be transferred to the insulating member 530 when the current collectors are joined together by the high-energy wire 2 . In the fourth to seventh embodiments, by providing the contact regions R41, R51, R61, and R71, it is also possible to ensure the regions where the current collectors can be bonded to each other, thereby facilitating the stable connection of the current collectors to each other. In particular, it is possible to ensure the bonding sites between the current collectors without requiring the mutual positioning of the bonded current collectors to be highly accurate. In addition, it is preferable that the sealing plates 120 and 130 each have a pair of long sides arranged in parallel with each other and short sides arranged in parallel with each other and shorter than the pair of long sides. Here, the direction in which the long sides extend is referred to as the long side direction. In the above-mentioned embodiments 1 to 7, in the process of connecting the current collectors to each other by irradiating the high-energy beam 2, the sealing plate 130 is arranged approximately parallel to the YZ plane, and when the sealing plate 130 is projected onto the opening 114 along the X direction, the sealing plate 130 overlaps approximately 100% of the area of ​​the opening 114, but the present technology is not limited to this. For example, in the above-mentioned process, the sealing plate 130 may be in a state of being inclined relative to the YZ plane, for example, it may be inclined to a degree of 30° or less (more preferably to a degree of 15° or less, and further preferably to a degree of 10° or less). In addition, it is preferred that when the sealing plate 130 is projected onto the opening 114 along the X direction, the sealing plate 130 is in a state of overlapping with an area of ​​60% or more (preferably to a degree of 80% or more, and more preferably to a degree of 90% or more) of the area of ​​the opening 114. Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A method for manufacturing a secondary battery, the secondary battery comprising: an electrode body comprising a first electrode, a second electrode having a polarity different from that of the first electrode, and a first electrode sheet electrically connected to the first electrode; a case that accommodates the electrode body and includes a case body having a first opening and a first sealing plate that seals the first opening; a first current collecting component electrically connected to the first electrode sheet; a second current collecting member connected 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, The method for manufacturing the secondary battery is characterized in that it comprises the following steps, namely: The step of inserting the electrode body into the casing body; and After the electrode body is inserted into the case body, the first current collecting member electrically connected to the first electrode via the first electrode sheet is joined to the second current collecting member electrically connected to the first electrode terminal. The step of joining the first current collecting member to the second current collecting member includes irradiating at least one of the first current collecting member and the second current collecting member with high energy rays from between the case body and the first sealing plate to join the first current collecting member to the second current collecting member.

2. The method for manufacturing a secondary battery according to claim 1, characterized in that: The housing body has a second opening at a position opposite to the first opening, and the second opening is sealed by a second sealing plate. The second sealing plate is provided with a second electrode terminal. The first electrode sheet is provided at an end portion of the electrode body on the first sealing plate side. A second electrode sheet electrically connected to the second electrode is provided at an end of the electrode body on the second sealing plate side. The method for manufacturing a secondary battery further includes the step of electrically connecting the second electrode sheet and the second electrode terminal.

3. The method for manufacturing a secondary battery according to claim 2, characterized in that: Before the electrode body is inserted into the case main body, the second electrode terminal provided on the second sealing plate is electrically connected to the second electrode sheet.

4. The method for manufacturing a secondary battery according to claim 2, characterized in that: The second electrode includes a second electrode core and a second electrode active material layer formed on the second electrode core. The step of inserting the electrode body into the housing body comprises: A first step is to insert a portion of the electrode body into the case body so that an end portion of the second electrode active material layer on the second opening side is disposed outside the case body; and A second step is to place the end of the second electrode active material layer on the second opening side in the housing body after the first step. After the first step and before the second step, the second electrode terminal provided on the second sealing plate is electrically connected to the second electrode sheet.

5. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: The first electrode includes a first electrode core and a first electrode active material layer formed on the first electrode core. The first current collecting member and the second current collecting member are joined together in a state where an end portion of the first electrode active material layer on the first opening side is arranged inside the case body.

6. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: The first current collecting member and the second current collecting member are joined to each other in a state where a resin member is disposed between a position where the high-energy beam is irradiated and a main body of the electrode body in a direction perpendicular to the first sealing plate.

7. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: The second current collecting member is thicker than the first current collecting member.

8. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: The first current collecting member includes a first region extending along the first sealing plate, a second region extending in a direction intersecting the first sealing plate, and a first bent portion provided between the first region and the second region. The second current collecting member includes a third region extending along the first sealing plate, a fourth region extending in a direction intersecting the first sealing plate, and a second bent portion provided between the third region and the fourth region. The first region and the third region are arranged to overlap each other, and the first region is located closer to the electrode body than the third region. The first region is connected to the first electrode sheet. The second region and the fourth region are joined.

9. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: A high-energy beam is irradiated toward a boundary between the first current collecting member and the second current collecting member, wherein the boundary is formed by arranging an end portion of the first current collecting member and an end portion of the second current collecting member in a staggered manner.

10. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: A contact surface formed by the first current collecting member and the second current collecting member contacting each other, and a separation portion provided at an end of the contact surface and formed by separating the first current collecting member and the second current collecting member are formed, and The end of the contact surface is irradiated with high-energy rays through the separation portion.

11. The method for manufacturing a secondary battery according to any one of claims 1 to 4, characterized in that: A high-energy beam is irradiated onto a region of the second current collecting member where a gap is formed between the second current collecting member and the first sealing plate.

12. A secondary battery, characterized in that: have: an electrode body comprising a first electrode, a second electrode having a polarity different from that of the first electrode, and a first electrode sheet electrically connected to the first electrode; a case that accommodates the electrode body and includes a case body having a first opening and a first sealing plate that seals the first opening; a first current collecting component electrically connected to the first electrode sheet; a second current collecting member connected 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, The secondary battery is formed with a contact surface formed by the first current collecting member and the second current collecting member contacting each other. The first current collecting member and the second current collecting member are joined to each other at an end portion of the contact surface.

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