Secondary battery and method for manufacturing same

Abstract

The invention provides a secondary battery and a manufacturing method thereof. The housing main body has an outer peripheral surface portion, a first end face, and a second end face. The outer peripheral surface portion extends around an axis in a first direction. The first end surface is located at an end of the first side and extends in a direction intersecting the first direction. The second end surface is located at an end of the second side and extends in a direction intersecting the first direction. The first sealing plate has a first covering portion. The first covering portion covers at least a portion of the first end surface from the first direction. The second sealing plate is provided with a second covering part. The second covering portion covers at least a portion of the second end surface from the first direction. A first joining portion is formed so as to span the outer peripheral surface portion and the first covering portion. A second joining portion is formed so as to span the outer peripheral surface portion and the second covering portion.

Description

Technical Field The present technology relates to a secondary battery and a method for manufacturing the same. Background Art As a prior art document that discloses the structure of a secondary battery, there is Japanese Patent Gazette No. 4537353. The secondary battery described in Japanese Patent Gazette No. 4537353 includes an electrode body, a shell, and a cover plate. The electrode body is placed in the shell. The shell is provided with openings at both ends for inserting the electrode group. The cover plate is combined with the opening. The cover plate is arranged on the inner side of the shell to seal the opening. In the secondary battery described in Japanese Patent No. 4537353, the sealing plate cannot be positioned relative to the case body, and there is a possibility that the joint between the case body and the sealing plate cannot be stably formed. Therefore, there is still room for improving the reliability of the joint. Summary of the invention The present technology has been made to solve the above-mentioned problems, and an object of the present invention is to provide a secondary battery and a method for manufacturing the same that can improve the reliability of a joint between a case body and a sealing plate. The present technology provides the following secondary batteries.

[0001] A secondary battery, comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and a shell that accommodates the electrode body; The housing comprises: a housing body having a first opening located at an end portion on a first side in a first direction, and a second opening located at an end portion on a second side opposite to the first side in the first direction; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening; The housing body includes an outer peripheral surface portion extending around the axis of the first direction, a first end surface located at the end portion of the first side and extending in a direction intersecting the first direction, and a second end surface located at the end portion of the second side and extending in a direction intersecting the first direction. The first sealing plate has a first covering portion covering at least a portion of the first end surface from the first direction, The second sealing plate has a second covering portion that covers at least a portion of the second end surface from the first direction. A first joint portion is formed so as to span the outer peripheral surface portion and the first covering portion. A second joining portion is formed so as to straddle the outer peripheral surface portion and the second covering portion.

[0002] In the secondary battery described in [1], The housing body includes a joining portion extending along the first direction on the outer peripheral surface portion.

[0003] In the secondary battery described in [1] or [2], The electrode body comprises: Main body; a first electrode sheet group electrically connected to the first electrode and located on the first side relative to the main body; and A second electrode sheet group is electrically connected to the second electrode and is located on the second side with respect to the main body.

[0004] The secondary battery according to any one of [1] to [3], comprising: a first electrode terminal electrically connected to the first electrode and mounted on the first sealing plate; and a second electrode terminal which is electrically connected to the second electrode and is mounted on the second sealing plate.

[0005] The secondary battery according to any one of [1] to [4], comprising: a first separator located between the electrode body and the first sealing plate; and a second separator located between the electrode body and the second sealing plate.

[0006] In the secondary battery described in any one of [1] to [5], The housing body has an inner peripheral surface extending around the axis in the first direction. The first sealing plate has a first portion which enters the interior of the housing body closer to the first opening and faces the inner peripheral surface of the housing body. The second sealing plate has a second portion which enters the interior of the housing body closer to the second opening and faces the inner peripheral surface of the housing body. The first joining portion and the second joining portion are welded portions. The present technology provides the following method for manufacturing a secondary battery.

[0007] A method for manufacturing a secondary battery, comprising the following steps: Prepare a shell body, wherein the shell body has a first opening located at an end portion of a first side in a first direction, a second opening located at an end portion of a second side in the first direction opposite to the first side, an outer peripheral surface portion extending around an axis in the first direction, a first end surface located at an end portion of the first side and extending in a direction intersecting the first direction, and a second end surface located at an end portion of the second side and extending in a direction intersecting the first direction; inserting an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode into the interior of the housing body; The first opening is sealed by bringing a first sealing plate into contact with the first end surface so as to cover at least a portion of the first end surface from the first direction, and performing a joining process from the outer peripheral side around the axis in the first direction to form a joining portion so as to straddle the first sealing plate and the outer peripheral surface of the housing body; and The second opening is sealed by bringing the second sealing plate into contact with the second end surface so as to cover at least a portion of the second end surface from the first direction, and performing a joining process from the outer peripheral side around the axis in the first direction to form a joining portion so as to span the outer peripheral surface of the second sealing plate and the shell body.

[0008] In the method for manufacturing a secondary battery described in [7], The case body is formed by bending a plate-shaped member into a cylindrical shape and joining both ends of the plate-shaped member bent into the cylindrical shape to each other.

[0009] In the method for manufacturing a secondary battery described in [8], The process of joining the two ends of the plate-like member to each other includes welding by irradiating energy beams a plurality of times.

[0010] In the method for manufacturing a secondary battery described in [8], The process of joining the two ends of the plate-like member to each other includes welding by irradiating energy beams multiple times. The welding process of irradiating the energy beam multiple times has the following steps, namely: welding a first region of the housing body including the first side end portion; and The second region of the housing body including the second side end is welded. In welding the first region and the second region, the end portion on the first side and the end portion on the second side serve as the start point or end point of welding. When the end portion on the first side becomes the starting point of welding, the end portion on the second side becomes the starting point of welding. When the end portion on the first side becomes the end point of welding, the end portion on the second side becomes the end point of welding.

[0011] In the method for producing a secondary battery according to any one of [7] to

[10] , In the step of sealing the first opening, the process of forming the joining portion includes welding by irradiating energy beams a plurality of times.

[0012] In the method for manufacturing a secondary battery described in

[11] , The energy beam is irradiated a plurality of times to perform welding so that the first sealing plate and the housing body are joined via the plurality of joining portions. Adjacent joining portions among the plurality of joining portions are formed so that parts of the adjacent joining portions overlap with each other.

[0013] In the method for producing a secondary battery according to any one of [7] to

[12] , At least one of the step of sealing the first opening and the step of sealing the second opening includes the step of rotating the case body around an axis in the first direction.

[0014] In the method for manufacturing a secondary battery described in

[13] , At least one of the step of sealing the first opening and the step of sealing the second opening includes pressing the case body until the case body is deformed so that the electrode body is sandwiched between the case body.

[0015] The method for manufacturing a secondary battery according to

[13] or

[14] comprises the following steps: Before the step of sealing the first opening, temporarily joining the first sealing plate to the housing body; and Before the step of sealing the second opening, the second sealing plate is temporarily joined to the case body.

[0016] In the method for producing a secondary battery according to any one of [7] to

[15] , At least a part of the step of sealing the first opening and the step of sealing the second opening are performed simultaneously.

[0017] In the method for producing a secondary battery according to any one of [7] to

[16] , The housing body has an inner peripheral surface extending around the axis in the first direction. The first sealing plate has a first portion which enters the interior of the housing body closer to the first opening and faces the inner peripheral surface of the housing body. The second sealing plate has a second portion which enters the interior of the housing body closer to the second opening and faces the inner peripheral surface of the housing body. In the step of sealing the first opening and the step of sealing the second opening, the first sealing plate and the shell body are welded, and the second sealing plate and the shell body are welded by irradiating energy lines from the outer peripheral side of the axis around the first direction. 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 This is a front view showing the structure of a secondary battery according to one embodiment of the present technology. 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 yes Figure 1 A front cross-sectional view of a secondary battery is shown. Figure 6 It is a front view showing a negative electrode original plate before forming a negative electrode plate. Figure 7 yes Figure 6 VII-VII cross-sectional view of the negative electrode original plate shown. Figure 8 It is a front view showing a negative electrode plate formed from a negative electrode original plate. Fig. 9 It is a front view showing a positive electrode original plate before forming a positive electrode plate. Fig.10 yes Fig. 9 XX cross-sectional view of the positive electrode original plate shown. Fig.11 It is a front view showing a positive electrode plate formed from a positive electrode original plate. Fig.12 It is a diagram showing an electrode body and a current collector taken out from a secondary battery. Fig.13 It is a front view of the connection structure between the negative electrode sheet group and the negative electrode collector. Fig.14 It is a cross-sectional view of the connection structure between the negative electrode sheet group and the negative electrode current collector. Fig.15 It is a diagram showing the step of inserting the electrode body into the case body. Fig.16 This is a diagram showing a step of placing a separator between a sealing plate and an electrode body. Fig.17 It is a cross-sectional view showing a joining portion of a case included in a secondary battery according to one embodiment. Fig.18 It is a perspective view showing a joined state of a case body and a first sealing plate included in a secondary battery according to a comparative example. Fig.19 This is a flowchart showing a method for manufacturing a secondary battery according to one embodiment. Fig. 20 This is a bottom view showing the joining method when molding the case body. Fig.21 It is a bottom view showing a joining method when molding a case body according to a first modification example of one embodiment. Fig. 22 It is a perspective view showing a method of joining a case body and a first sealing plate included in a secondary battery according to one embodiment. Fig.23 It is a side view showing a state immediately after the casing body and the first sealing plate are started to be joined together. Fig.24 It is a side view showing a state where the short side portions are joined while the case body and the first sealing plate are rotated. Fig.25 It is a side view showing a state where the long side portions are joined while the case body and the first sealing plate are rotated. Fig.26 It is a bottom view showing a joining path when joining the case body and the first sealing plate. Fig. 27 It is a bottom view showing a first welding path when joining the case body and the first sealing plate according to the modification. Fig.28 It is a bottom view showing a second welding path when joining the case body and the first sealing plate according to the modification. Fig.29 It is a bottom view showing a third welding path when joining the case body and the first sealing plate according to the modification. Fig.30 It is a perspective view showing a joined state of a case body and a first sealing plate included in a secondary battery according to a second modification of one 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 the 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 as the first direction, the short side direction of the electrode body perpendicular to the first direction and observed from the first direction is set as the Y direction as the second direction, and the long side direction of the electrode body perpendicular to the first direction and observed from the first direction is set as the Z direction as the third 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. (Overall structure of the battery) Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 4 They are respectively viewed from the direction of arrow II, arrow III, and arrow IV. Figure 1The diagram shows the state of the secondary battery 1. Figure 5 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 5 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 first sealing plate 120 , and a second 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 on the side 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 first sealing plate 120 and a second sealing plate 130 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 joint portion 115 shown in the example in the figure can be formed into a square tube shape by joining them together (for example, laser welding). The corner of the "square tube shape" can also have an R shape. The joint portion 115 in this embodiment extends along the first direction (X direction) on the outer peripheral surface of the shell body 110. 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 3 As shown, a first opening 113 is provided at the end of the first side in the first direction (X direction) of the housing body 110. The first opening 113 is sealed by a first sealing plate 120. The first opening 113 and the first sealing plate 120 have a substantially rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. The first sealing plate 120 is provided with a negative electrode terminal 301 (first electrode terminal), a liquid injection hole 124, and a gas exhaust valve 125. The positions of the negative electrode terminal 301, the liquid injection hole 124, and the gas exhaust valve 125 can be changed as appropriate. like Figure 4 As shown, a second opening 114 is provided at the end of the second side opposite to the first side in the first direction (X direction) of the housing body 110. The second opening 114 is sealed by a second sealing plate 130. The second opening 114 and the second sealing plate 130 have a substantially rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. The second sealing plate 130 is provided with a positive electrode terminal 302 (second electrode terminal), a liquid injection hole 134, and a gas exhaust valve 135. The positions of the positive electrode terminal 302, the liquid injection hole 134, and the gas exhaust valve 135 can be changed as appropriate. The first sealing plate 120 and the second sealing plate 130 are made of metal. Specifically, the first sealing plate 120 and the second sealing plate 130 are made of aluminum, aluminum alloy, iron, iron alloy, or the like. In the present embodiment, the thickness of each of the first sealing plate 120 and the second sealing plate 130 is thicker than the thickness (plate thickness) of the housing body 110. Thus, in the first sealing plate 120 and the second sealing plate 130, which occupy a smaller volume than the housing body 110, the thermal influence when forming the first bonding portion 140 and the second bonding portion 141 described later can be mitigated, and perforation during bonding can be suppressed. The negative electrode terminal 301 is electrically connected to the negative electrode of the electrode body 200 . The negative electrode terminal 301 is attached to the first sealing plate 120 , that is, the case 100 . The positive electrode terminal 302 is electrically connected to the positive electrode of the electrode body 200 . The positive electrode terminal 302 is attached to the second 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 holes 124 and 134 are sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used. The exhaust valves 125 and 135 break when the pressure in the housing 100 reaches a predetermined value or more, and exhaust the gas in the housing 100 to the outside. 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 can 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 provided on each positive plate can also be stacked to form a positive electrode sheet group, and the negative electrode sheets provided on each negative plate can also be stacked to form a negative electrode sheet group. like Figure 5 As shown, the case 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the case 100 so that the winding axis thereof 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 electrode body 200 includes a main body (a portion in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween), a negative electrode sheet group 220 (a first electrode sheet group), and a positive electrode sheet group 250 (a second 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 electrode body 200 on the first side in the first direction (X direction) relative to the main body. The first side in this embodiment is the first sealing plate 120 side. The positive electrode sheet group 250 is located at the end of the second side in the first direction (X direction) relative to the main body. The second side in this embodiment is the second sealing plate 130 side. The negative electrode sheet group 220 and the positive electrode sheet group 250 are formed so as to protrude from the center portion of the electrode body 200 toward the first sealing plate 120 or the second sealing plate 130 , respectively. The current collector 400 includes a negative electrode current collector 410 (first current collector) and a positive electrode current collector 420 (second current collector). The negative electrode current collector 410 and the positive electrode current collector 420 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 410 is disposed on the first sealing plate 120 via a resin insulating member. The negative electrode current collector 410 is electrically connected to the negative electrode sheet group 220 and the negative electrode terminal 301. The negative electrode current collector 410 is made of a conductive material (more specifically, metal), such as copper or a copper alloy. The positive electrode collector 420 is arranged on the second sealing plate 130 via an insulating member made of resin. The positive electrode collector 420 is electrically connected to the positive electrode sheet group 250 and the positive terminal 302. The positive electrode collector 420 is composed of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode sheet group 250 can also be electrically connected to the second sealing plate 130 directly or via the positive electrode collector 420. In this case, the second sealing plate 130 can also play the role of the positive terminal 302. (Structure of Electrode Body 200) Figure 6 2 is a front view showing a negative electrode original plate 210S before forming a negative electrode plate 210 (first electrode). Figure 7 yes Figure 6 The VII-VII cross-sectional view of the negative electrode original plate 210S shown in FIG. Figure 8 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 the negative electrode original plate 210S. Figure 6 and Figure 7 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil. The negative electrode 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 to remove the water contained in the negative electrode active material layer slurry, thereby forming 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 Figure 8 As shown, at one end in the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 230 formed by the 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. As a result, the negative electrode sheet group 220 is connected to the negative electrode plate 210 (first electrode). 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 410. In addition, the shape of the negative electrode sheet 230 is not limited to Figure 8 The shape illustrated in . Fig. 9 2 is a front view showing a positive electrode original plate 240S before forming a positive electrode plate 240 (second electrode). Fig.10 yes Fig. 9 The XX-sectional view of the positive electrode original plate 240S shown in FIG. Fig.11 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. 9 and Fig.10 As shown, the positive electrode original plate 240S includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is an aluminum foil or an aluminum alloy foil. The positive electrode 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 to remove the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry, thereby forming the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, by compressing the positive electrode active material layer 242, a 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. The positive electrode original plate 240S 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.11 As shown, at one end portion in the width direction of the positive electrode plate 240 formed by the positive electrode original plate 240S, a plurality of positive electrode sheets 260 formed by the 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 in a state of being connected to the positive electrode plate 240 (the second electrode). The positions of the respective plurality of positive electrode sheets 260 and the lengths in the protruding direction are appropriately adjusted in consideration of the state in which the positive electrode sheet group 250 is connected to the positive electrode collector 420. In addition, the shape of the positive electrode sheet 260 is not limited to Fig.11 The shape illustrated in . The 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 negative electrode sheet group 220 is smaller than the thickness of the positive electrode sheet group 250. (Connection Structure of Electrode Body 200 and Current Collector 400) Fig.12 FIG. 2 is a diagram showing an electrode body 200 and a current collector 400 taken out of a secondary battery 1. Fig.12 As shown in FIG. 1 , the electrode body 200 is formed by stacking two electrode bodies 201 and 202, each of which is a wound electrode body. Fig.12In the example shown, a structure in which two wound electrode bodies are stacked is shown, but the electrode body 200 may be composed of one wound electrode body, three or more wound electrode bodies, or a stacked electrode body. The negative electrode sheet group 220 is joined to the negative electrode current collector 410 at a joining portion 434 , and the positive electrode sheet group 250 is joined to the positive electrode current collector 420 at a joining portion 454 . Fig.13 It is a front view of the connection structure between the negative electrode sheet group and the negative electrode collector. Fig.14 It is a cross-sectional view of the connection structure between the negative electrode sheet group and the negative electrode current collector. like Fig.13 and Fig.14 As shown, the negative electrode current collector 410 electrically connects the negative electrode terminal 301 and the negative electrode sheet group 220. The negative electrode current collector 410 in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the first sealing plate 120. The negative electrode current collector 410 includes a first conductive member 430 and a second conductive member 440. The first conductive member 430 and the second conductive member 440 are joined at a joining portion 433. The first conductive member 430 and the second conductive member 440 are joined by, for example, laser welding. The first conductive member 430 is bonded to the negative electrode sheet group 220 at a bonding portion 434. The bonding portion 434 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the first conductive member 430 and the negative electrode sheet group 220 are bonded, for example, by ultrasonic bonding. The second conductive member 440 is connected to the negative terminal 301 at a joint portion 441. The joint portion 441 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In the present embodiment, the negative terminal 301 and the second conductive member 440 are joined, for example, by providing a through hole in the second conductive member 440, inserting the negative terminal 301 into the through hole, riveting the negative terminal 301 to the second conductive member 440, and then welding the riveted portion and the second conductive member 440. The first conductive member 430 includes a first planar portion 431 and a second planar portion 432. The first planar portion 431 is connected to the second conductive member 440. The second planar portion 432 is connected to the negative electrode sheet group 220. The second planar portion 432 is disposed along the first sealing plate 120. A step portion 435 is provided between the first plane portion 431 and the second plane portion 432. With respect to the step portion 435, the first plane portion 431 and the second plane portion 432 are positioned differently in the first direction (X direction) when the secondary battery 1 is assembled. Thus, the first plane portion 431 and the second plane portion 432 can be arranged in one direction. The step portion 435 extends along the third direction (Z direction). A first insulating member 510 (resin member) is disposed between the negative electrode terminal 301 and the first sealing plate 120. A second insulating member 520 (resin member) is disposed between the first sealing plate 120 and the first conductive member 430 and the second conductive member 440. In addition, the first insulating member 510 and the second insulating member 520 may be an integral member. The negative electrode terminal 301 is attached to the first sealing plate 120 via the first insulating member 510 . The negative electrode terminal 301 is exposed outside the first sealing plate 120 and reaches the second conductive member 440 of the negative electrode collector 410 provided on the inner surface of the first sealing plate 120 . As the assembly order of each component, first, the negative electrode terminal 301 and the second conductive component 440 are mounted on the first sealing plate 120 together with the first insulating component 510 and the second insulating component 520. Next, the first conductive component 430 electrically connected to the electrode body 200 is mounted on the second conductive component 440. At this time, the first conductive component 430 is arranged on the first insulating component 510 in such a manner that a part of the first conductive component 430 overlaps with the second conductive component 440. Next, the first conductive component 430 and the second conductive component 440 are welded and connected at the joint 434. The negative electrode terminal 301 may be electrically connected to the first sealing plate 120 . In addition, the first sealing plate 120 may also play the role of the negative electrode terminal 301 . In addition, Fig.13 and Fig.14 In FIG. 4 , the negative electrode current collector 410 is exemplified as being composed of two members (the first conductive member 430 and the second conductive member 440 ), but the negative electrode current collector 410 may be composed of a single member. exist Fig.13 and Fig.14 , the connection structure on the negative electrode side is shown, but the basic connection structure on the positive electrode side is also the same as that on the negative electrode side. (Step of Inserting Electrode Body 200) Fig.15 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.15 As shown, a resin insulating sheet 700 (electrode body holder) is arranged between the electrode body 200 and the case body 110 . The insulating sheet 700 may be made of, for example, resin. More specifically, the insulating sheet 700 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO). The insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers 50% or more of the outer surface of the electrode body, and more preferably covers 70% or more of the area. The insulating sheet 700 preferably covers the entirety of four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for at least two surfaces each having the negative electrode sheet group 220 and the positive electrode sheet group 250 formed thereon. Fig.16 This is a diagram showing a step of placing the first separator 600 between the first sealing plate 120 and the electrode body 200 . like Fig.16 As shown, the negative electrode sheet group 220 arranged from the electrode body 200 toward the first sealing plate 120 is bent from the center of the first sealing plate 120 in the Y direction toward the end, and then folded back toward the center. The separator 600 is provided in a manner to accommodate the bent portion of the negative electrode sheet group 220. The first separator 600 is arranged between the electrode body 200 and the first sealing plate 120. The first spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are respectively slid along the Y direction from the end side toward the center side of the first sealing plate 120 and are engaged with each other through the engaging parts 630a and 630b. Thus, the first spacer 600 is fixed to the first sealing plate 120 via the second insulating component 520, so that the position stability of the first spacer 600 is increased. The secondary battery 1 according to this embodiment includes a second separator (not shown). The second separator is disposed between the electrode assembly and the second sealing plate. The second separator may have the same structure as the first separator 600. In addition, the first separator 600 and the second separator may have different shapes. (Joint Structure of Case Body 110 and Sealing Plates 120, 130) Fig.17 1 is a cross-sectional view showing a joint portion of a case included in a secondary battery according to one embodiment. Fig.17 In order to facilitate understanding of the present invention, structures other than the housing 100 are omitted. like Fig.17 As shown, the housing body 110 has an outer peripheral surface portion 116 , a first end surface 117 , and a second end surface 118 . The outer peripheral surface 116 extends around the axis of the first direction (X direction). In addition, the outer peripheral surface 116 extends along the first direction (X direction). In addition, the outer peripheral surface 116 extends substantially parallel to the first direction (X direction), but due to processing errors during the manufacture of the shell body 110, there is a situation where it is inclined from the first direction (X direction). In addition, the surface of the outer peripheral surface 116 may also be formed with concave and convex or step differences. The first end surface 117 is located at the end of the first side in the first direction (X direction). The first end surface 117 extends in a direction intersecting the first direction (X direction). In the present embodiment, the first end surface 117 extends in a direction substantially orthogonal to the first direction (X direction). The first end surface 117 extends in a direction substantially orthogonal to the first direction (X direction), so that the first sealing plate 120 can be easily abutted. The second end face 118 is located at the end of the second side in the first direction (X direction). The second end face 118 extends in a direction intersecting the first direction (X direction). In the present embodiment, the second end face 118 extends in a direction substantially orthogonal to the first direction (X direction). The second end face 118 extends in a direction substantially orthogonal to the first direction (X direction), so that the second sealing plate 130 is easily abutted. The first sealing plate 120 has a first covering portion 127. The first covering portion 127 covers at least a portion of the first end surface 117 from the first direction (X direction). Therefore, the first sealing plate 120 is easily and stably positioned relative to the housing body 110. The first covering portion 127 in this embodiment covers the entire surface of the first end surface 117 from the first direction (X direction). The second sealing plate 130 has a second covering portion 137. The second covering portion 137 covers at least a portion of the second end surface 118 from the first direction (X direction). Therefore, the second sealing plate 130 is easily and stably positioned relative to the housing body 110. The second covering portion 137 in this embodiment covers the entire surface of the second end surface 118 from the first direction (X direction). The first joint portion 140 is formed so as to span the outer peripheral surface portion 116 and the first covering portion 127. The first end surface 117 and the first covering portion 127 are joined by the first joint portion 140. The second joint portion 141 is formed so as to span the outer peripheral surface portion 116 and the second covering portion 137. The second end surface 118 and the second covering portion 137 are joined by the second joint portion 141. The first joint portion 140 and the second joint portion 141 are formed, for example, by laser welding. In addition, the first joint portion 140 and the second joint portion 141 are not limited to laser welding, and may also be a joining method such as ultrasonic welding or resistance welding. Since the first joint portion 140 and the second joint portion 141 are located on the outer peripheral surface portion 116 of the case body 110, they can be arranged at a position away from the resin insulating member provided between the electrode terminal 300 and the sealing plates 120 and 130, compared with the case where the sealing plate is entirely inserted into the inner side of the case body and the joint portion is formed between the outer peripheral surface of the sealing plate and the end surface of the case body. As a result, the thermal influence on the insulating member during the joining can be reduced. Since the secondary battery according to the comparative example has a different casing structure from the secondary battery 1 according to one embodiment of the present technology, the same structure as the secondary battery 1 according to one embodiment of the present technology will not be described repeatedly. Fig.18 It is a perspective view showing a joined state of a case body and a first sealing plate included in a secondary battery according to a comparative example. like Fig.18 As shown, the secondary battery 9 according to the comparative example includes a case 900 . The case 900 includes a case body 910 and a first sealing plate 920 . The housing body 910 has a first end face 917 and an inner peripheral face 919. The first end face 917 is located at the first side end in the first direction (X direction). The inner peripheral face 919 extends toward the inside of the housing body 910 around the axis of the housing body 910 in the first direction (X direction). The first sealing plate 920 covers the first opening 913. The outer periphery of the first sealing plate 920 contacts the inner periphery 919 of the housing body 910. The inner periphery 919 and the outer periphery of the first sealing plate 920 are joined by a first joining portion 940. The first joining portion 940 is formed so as to span the outer surface of the first sealing plate 920 and the end surface of the housing body 910. When forming the first joint portion 940, when the first sealing plate 920 is inserted into the interior of the shell body 910, the first sealing plate 920 can also be configured at any position in the first direction (X direction), so it is difficult to determine the position of the first sealing plate 920 in the first direction (X direction). On the other hand, Fig.17 As shown, in this embodiment, since the first covering portion 127 of the first sealing plate 120 can be brought into contact with the first end surface 117 of the housing body 110 relative to the housing body 110, it is easy to position the first sealing plate 120 relative to the housing body 110. Thus, it is easy to join the housing body 110 and the first sealing plate 120. Therefore, the first joining portion 140 can be stably formed. Hereinafter, a method for manufacturing the secondary battery according to the present embodiment will be described. Fig.19This is a flowchart showing a method for manufacturing a secondary battery according to one embodiment. Fig. 20 This is a bottom view showing the joining method when forming the shell body. In addition, in order to easily understand the welding path, Fig. 20 The welding path in FIG. 1 is shown in a manner that deviates from the position of the actual welded portion. like Fig.19 As shown, as a manufacturing method of the secondary battery 1 involved in this embodiment, first, a shell body is prepared (S1 process). In the process of preparing the shell body 110 (S1 process), a square cylindrical member constituting the shell body 110 is formed by bending a plate-like member into a cylindrical shape and joining the two ends of the plate-like member bent into a cylindrical shape. In joining the two ends of the plate-like component, the two ends of the plate-like component can be welded by irradiating the energy beam multiple times. In addition, it is not necessarily necessary to irradiate multiple times. In this embodiment, the two ends of the plate-like component are welded by irradiating the laser twice. Thus, the joint 115 is formed. Specifically, first, in the first laser irradiation, the laser (not shown) passes through the Fig. 20 The first region R1 of the housing body 110 including the first side end is welded along the welding path 115a. Next, in the second laser irradiation, the laser passes through the first region R1 along the direction of the arrow. Fig. 20 The second region R2 including the second side end portion of the housing body 110 is welded using the welding path 115b. In welding the first region R1 and the second region R2, the first end and the second end serve as the start or end point of welding. In the present embodiment, the first end and the second end serve as the end point of welding. The laser welding divided into two times can be performed in a manner that the welding distance of one side is longer than the welding distance of the other side. In this embodiment, the welding path 115b for welding the second region R2 is longer than the welding path 115a for welding the first region R1. As a result, compared with the case where the welding distances are the same, the distance from the end point of the welding path 115a to the starting point of the welding path 115b can be shortened. As a result, since the distance where the laser is not irradiated can be shortened, the overall welding time can be shortened. Fig.21 It is a bottom view showing a joining method when molding a case body according to a first modification example of one embodiment. In the first laser irradiation in this modification, the laser light (not shown) passes through the Fig.21 The second region R2 including the second side end of the housing body 110A is welded along the welding path 115c. Next, in the second laser irradiation, the laser passes through the second region R2 along the direction of the arrow. Fig.21The first region R1 including the first side end of the case body 110A is welded along the welding path 115d in the welding path 115d. Thus, the joint portion 115A is formed. In the method for joining the case body of the secondary battery according to this modification, the end of the first side and the end of the second side serve as the starting point of welding. Thus, the molten portion during welding flows toward the opening side of the case body 110A, which can more effectively prevent the abutment with the sealing plate from becoming unstable. Next, if Fig.19 As shown, the first electrode terminal is electrically connected to the electrode body (step S2 ). In this embodiment, the negative electrode sheet group 220 of the electrode body 200 is electrically connected to the negative electrode terminal 301 (first electrode terminal) provided on the first sealing plate 120 via the negative electrode current collector 410 . Next, the positive electrode sheet group 250 of the electrode assembly 200 is connected to the first conductive member 430 of the positive electrode current collector 420. This step may be performed after the step S3 described later. Next, the electrode body 200 is inserted into the interior of the case body 110 (step S3). Fig.15 As shown, the electrode body 200 is inserted into the case body 110 by inserting the positive electrode current collector 420 from the first opening 113 . Next, the second electrode terminal is connected to the electrode body (step S4 ). In this embodiment, the positive electrode sheet group 250 of the electrode body 200 is electrically connected to the positive electrode terminal 302 (second electrode terminal) provided on the second sealing plate 130 via the positive electrode collector 420 . At any time during the above steps, after the electrode sheet is folded, the first separator 600 and the second separator are disposed between the electrode body 200 and the sealing plates 120 and 130 . Next, if Fig.19 As shown, the housing body 110 and the sealing plates 120 and 130 are temporarily joined (step S5 ). Before the process of sealing the first opening 113, at least a portion of the first end face 117 covering the first opening 113 (the first covering portion 127) is temporarily joined to the first end face 117. Temporary joining is to temporarily fix the sealing plate to the shell body by point joining in the joining portion. The temporary joining in this embodiment is formed, for example, by point joining one point each on the four sides of a pair of first side portions 111 and a pair of second side portions 112. In addition, the temporary joining may also be, for example, a relatively short line (for example, less than 1 cm). In addition, temporary joining may not be necessary. Fig. 22 It is a perspective view showing a method of joining a case body and a first sealing plate included in a secondary battery according to one embodiment. Next, if Fig. 22 As shown, the first opening 113 is sealed (step S6). In addition, the second opening 114 is sealed (step S6). The process of sealing the first opening 113 and the process of sealing the second opening 114 are at least partially performed simultaneously. In the present embodiment, the process of sealing the first opening 113 and the process of sealing the second opening 114 are performed so that the start and the end are substantially the same. In addition, the process of sealing the first opening 113 and the process of sealing the second opening 114 may be repeated as part of these processes. In addition, these processes may be started at the same time but not ended at the same time, or may be started at different times but ended at the same time. In the case where part of these processes are repeated, either the sealing of the first opening 113 or the sealing of the second opening 114 may be performed first. The first opening 113 is sealed by bringing the first sealing plate 120 into contact with the first end face 117 in a manner that covers at least a portion of the first end face 117 from the first direction (X direction), and performing a joining process from the outer peripheral side of the axis around the first direction (X direction) to form a joining portion in a manner that spans the first sealing plate 120 and the outer peripheral surface portion 116 of the shell body 110. Similar to the joining of the first sealing plate 120, before the step of sealing the second opening 114, at least a portion of the second end face 118 covering the second opening 114 is temporarily joined to the second end face 118. The second sealing plate 130 is brought into contact with the second end face 118 so as to cover at least a portion of the second end face 118 from the first direction (X direction), and a joining process is performed from the outer peripheral side around the axis in the first direction (X direction) to form a joining portion so as to straddle the second sealing plate 130 and the outer peripheral surface portion 116 of the housing body 110, thereby sealing the second opening 114. In addition, temporary joining may not necessarily be performed. Fig.23 It is a side view showing a state immediately after the casing body and the first sealing plate are started to be joined together. Fig.24 It is a side view showing a state where the short side portions are joined while the case body and the first sealing plate are rotated. Fig.25 It is a side view showing a state where the long side portions are joined while the case body and the first sealing plate are rotated. Fig.26 FIG. 2 is a bottom view showing a joining path when joining the housing body and the first sealing plate. Figure 23 to Figure 25 In FIG. 1 , only the housing body is shown. Figure 23 to Figure 26 In the example of the joining on the negative electrode side, the same joining method can be adopted in the joining on the positive electrode side. In addition, in order to facilitate the understanding of the welding path, Fig.26The welding path in FIG. 1 is shown in a manner that deviates from the position of the actual welded portion. like Figure 22 to Figure 25 As shown, at least one of the steps of sealing the first opening 113 and sealing the second opening 114 can be performed by rotating the housing body 110 around an axis in the first direction (X direction) (in Fig. 22 In the present embodiment, in both the process of sealing the first opening 113 and the process of sealing the second opening 114, the shell body 110 is rotated to perform welding using the laser 3. The laser 3 may be a pulse type or a continuous oscillation type. The shell body 110 is pressed by a holding device (not shown) until elastic deformation occurs. Thus, the electrode body 200 is clamped by the shell body 110. The shell body 110 is pressed by the holding device at the first side portion 111 having a larger area than the second side portion 112. In addition, the deformation of the shell body 110 is not limited to elastic deformation. In addition, an insulating sheet 700 may be sandwiched between the shell body 110 and the electrode body 200. In this embodiment, the housing body 110 is continuously rotated while the housing body 110 is bonded. The focal length of the laser beam 3 is adjusted by moving the bonding device 2 to match the continuous rotation of the housing body 110 . like Fig.26 As shown, laser welding is started from a position P1 deviated from the boundary between the outer peripheral surface 116 and the first covering portion 127 in the first direction (X direction). When viewed from the direction intersecting the first direction (X direction), the laser passes through the welding path 116a which is inclined at more than 45° relative to the first end face 117. Thereafter, the laser is continuously irradiated to the boundary between the outer peripheral surface 116 and the first covering portion 127 starting from the welding path 116a. The entire circumference of the housing 100 in the first direction (X direction) is welded through the welding path 116b located at the boundary between the outer peripheral surface 116 and the first covering portion 127. After welding is repeated to a part of the welding path 116b, the laser is moved from the welding path 116b to the position P2 deviated in the first direction (X direction) through the welding path 116c, and the laser irradiation is stopped. By performing laser welding in this order, since the welding path 116 b along the first end surface 117 does not include a welding start point and an end point, stable heat input can be performed in the joining of the case body 110 and the first sealing plate 120 . In addition, in the present embodiment, the position P1 is offset from the boundary between the outer peripheral surface 116 and the first covering portion 127 to the housing body 110 side in the first direction (X direction), but may be offset to the first sealing plate 120 side. In addition, regarding the joining path of the present embodiment, an example is given in which the start and end points of welding are not included in the boundary between the outer peripheral surface 116 and the first covering portion 127, but the present invention is not limited to this structure. The joining path may also be a structure in which at least one of the start and end points of welding is located at the boundary between the outer peripheral surface 116 and the first covering portion 127. Next, a modification of the joining process by laser welding will be described. Figure 27 to Figure 29 FIG. 1 is a bottom view showing first to third welding paths when joining the housing body and the first sealing plate according to the modification. Figure 27 to Figure 29 In FIG. 1 , a state in which the first bonding portion 140 is formed on the second side surface portion 112 is exemplified. The first joint portion 140 involved in the modification is welded by irradiating the laser eight times. Specifically, the four plane portions, namely the pair of first side portions 111 and the pair of second side portions 112 in the outer peripheral surface portion 116, and the four corner portions therebetween are laser welded separately. In addition, irradiating the laser multiple times means that the laser is scanned multiple times, and does not mean each amplitude of the pulsed laser. like Fig. 27 As shown, a portion of the first joint portion 140 is formed by the first welding path 116d. The first welding path 116d is a path in which the laser irradiation is stopped at a position deviated from the first direction (X direction) after scanning the boundary between the outer peripheral surface portion 116 and the first covering portion 127 with the rotation of the housing body 110 stopped. Next, if Fig.28 As shown in FIG. 1 , after the housing body 110 is rotated and stopped, a part of the first joint portion 140 is formed by the second welding path 116e. The second welding path 116e is a path in which laser irradiation is started from a position deviated in the first direction (X direction) relative to the boundary between the outer peripheral surface portion 116 and the first covering portion 127 in a state in which the rotation of the housing body 110 is stopped, and after the laser is scanned on the boundary between the outer peripheral surface portion 116 and the first covering portion 127, the laser irradiation is stopped at a position deviated from the first direction (X direction). Next, if Fig.29As shown in FIG. 1 , after the housing body 110 is rotated and stopped, a portion of the first joint portion 140 is formed by the third welding path 116f. The third welding path 116f is a path in which laser irradiation is started from a position offset in the first direction (X direction) relative to the boundary between the outer peripheral surface portion 116 and the first covering portion 127 in a state in which the rotation of the housing body 110 is stopped, and the boundary between the outer peripheral surface portion 116 and the first covering portion 127 is scanned with laser light. As described above, laser welding is performed in a state where the rotation of the shell body 110 is stopped, and then the shell body 110 is rotated, and the next laser welding is performed in a state where the rotation of the shell body 110 is stopped. The above-mentioned action is repeated 8 times to form the first joint 140. When laser welding is performed, the shell body 110 is rotated 45° each time in a manner such that 4 plane portions or 4 corner portions are located directly below the joining device when viewed from the first direction (X direction). The focal length of the laser welding is changed and adjusted each time the shell body 110 is rotated. In addition, it is also possible to laser weld the four plane portions of a pair of first side portions 111 and a pair of second side portions 112 of the outer peripheral surface portion 116 in a state where the rotation of the shell body 110 is stopped, and laser weld each of the four corner portions while rotating the shell body 110. Similar to the welding path in the present embodiment, the starting point and the end point of the laser welding performed in multiple times in this modification are deviated from the first direction (X direction). The joining paths of the laser welding performed in multiple times are partially repeated in the direction along the first end face 117. In this modification, for example, the first welding path 116d and the second welding path 116e are partially repeated, and the second welding path 116e and the third welding path 116f are partially repeated. In this way, by welding by irradiating energy lines (laser) for a plurality of times, the first sealing plate 120 and the outer peripheral surface 116 of the housing body 110 are joined through a plurality of joints. Adjacent joints among the plurality of joints are formed so that a portion of each of the adjacent joints overlaps, so that the entire circumference of the housing 100 in the first direction (X direction) is reliably joined. After the above steps, the electrolyte solution is injected into the case 100 from the injection hole, and the secondary battery 1 is completed. Hereinafter, a secondary battery according to a second variant of one embodiment will be described. Since the bonding structure between the casing body and the sealing plate of the secondary battery according to this variant is different from that of the secondary battery 1 according to one embodiment of the present technology, the same structure as that of the secondary battery 1 according to one embodiment of the present technology will not be described repeatedly. Fig.30It is a perspective view showing a joined state of a case body and a first sealing plate included in a secondary battery according to a second modification of one embodiment. The secondary battery 1B according to the present modification example includes a case 100B. The case 100B includes a case body 110B and a first sealing plate 120B. The housing body 110B has an inner peripheral surface portion 119B. The inner peripheral surface portion 119B extends around the axis in the first direction (X direction). The first sealing plate 120B has a first covering portion 127B and a first portion 128B. The first covering portion 127B covers the end portion of the first side of the housing body 110B from the first direction (X direction). The first portion 128B enters the interior of the housing body 110B from the first opening 113 and faces the inner peripheral surface 119B of the housing body 110B. The first joint portion 140B is formed so as to span the first sealing plate 120B and the outer peripheral surface 116B. The first joint portion 140B is a welded portion formed by laser welding. In the process of sealing the first opening 113B, the first joint portion 140B is welded from the outer peripheral side (in the direction of the X axis) around the first direction (the X axis). Fig.30 The first sealing plate 120B and the first end surface 117 of the housing body 110B are welded by irradiating the first sealing plate 120B with a laser beam (in the DR1 direction). Since the first portion 128B is arranged to fit into the inner peripheral surface portion 119B of the case body 110B, the position of the first sealing plate 120B is further stabilized relative to the case body 110B. As a result, laser welding can be stably performed. The first sealing plate 120B has a convex portion 129B on its outer surface. The convex portion 129B is provided adjacent to the first covering portion 127B. This can prevent the first covering portion 127B of the first sealing plate 120B from being excessively melted during laser welding, thereby preventing weld collapse from occurring on the outer surface. In addition, Fig.30 , the structure of the negative electrode side is shown, but the same structure as the negative electrode side can also be adopted for the positive electrode side. In addition, the second sealing plate can also adopt the same structure as the first sealing plate 120B. Specifically, the second sealing plate has a second portion not shown. The second portion enters the interior of the shell body from the second opening and is opposite to the inner peripheral surface 119B of the shell body. The second joining portion is a welding portion formed by laser welding. The second sealing plate and the outer peripheral surface 116B of the shell body 110B are welded. When the first joint portion 140B and the second joint portion are formed by laser welding, even if the laser is directed from the outer peripheral side (at the center of the first direction (X direction) around the axis) Fig.30The laser beam can also be blocked by the first portion 128B (in the DR1 direction) by entering the inner peripheral surface portion 119B of the shell body 110B, thereby suppressing the penetration of the laser beam during laser welding. In the secondary battery 1 and the manufacturing method thereof according to one embodiment of the present technology, the shell body 110 and the first sealing plate 120 are joined by arranging the first sealing plate 120 in a manner abutting against the first end face 117 of the shell body 110. Compared with the case where the shell body and the sealing plate are joined by inserting the first sealing plate into the inner circumference of the shell body, the first sealing plate 120 can be stably positioned relative to the shell body 110 in the first direction (X direction), and the joining state of the joining portion can be stabilized. Thus, the reliability of the first joining portion 140 joining the shell body 110 and the first sealing plate 120 can be improved. By also adopting the same structure as the first sealing plate 120 on the second sealing plate 130 side, the reliability of the second joining portion 141 can be improved. In the secondary battery 1 according to one embodiment of the present technology, the case body 110 is joined using the joining portion 115 extending in the first direction (X direction), so that one metal plate can be bent and the bent ends can be joined to each other, thereby efficiently manufacturing the case body 110. In addition, by arranging the joining portion 115, the first joining portion 140, and the second joining portion 141 on the outer peripheral side of the case body 110, the joining portion 115 can be formed from the outer peripheral side of the case body 110 using one joining device, so that the case 100 can be efficiently joined. In the secondary battery 1 according to one embodiment of the present technology, by providing the negative electrode sheet group 220 (first electrode sheet group) and the positive electrode sheet group 250 (second electrode sheet group) of the electrode body 200, the energy density of the electrode body 200 can be increased, thereby forming a secondary battery with excellent output characteristics. In a secondary battery 1 according to one embodiment of the present technology, a negative terminal 301 (first electrode terminal) and a positive terminal 302 (second electrode terminal) are respectively provided on a first sealing plate 120 and a second sealing plate 130, and when the secondary battery 1 is placed on a portion of the peripheral surface of the shell body 110 as a bottom surface, the secondary battery can be made thinner. In the secondary battery 1 according to one embodiment of the present technology, the first separator 600 and the second separator can be used to prevent the electrode body 200 from being too close to the first sealing plate 120 and the second sealing plate 130. As a result, the electrode body 200 can be arranged not directly below the bonding position between the sealing plates 120 and 130 and the case body 110, so that even if the laser enters the inside of the case 100 from between the sealing plates 120 and 130 and the case body 110, damage to the electrode body 200 can be suppressed. In a modified example of the secondary battery 1 involved in one embodiment of the present technology, by providing a portion (the first portion 128B and the second portion) on the sealing plate that is opposite to the inner circumferential surface portion 119B of the shell body 110B, even if the laser during welding of the sealing plate and the shell body 110B passes from the welding position to the inner circumferential surface portion 119B side of the shell body 110B, the first portion 128B and the second portion of the sealing plate can block the laser, thereby preventing the laser from penetrating during welding. In the method for manufacturing the secondary battery 1 according to one embodiment of the present technology, the joint 115 , the first joint 140 , and the second joint 141 can be formed from the axial outer peripheral side in the first direction (X direction), so the case 100 can be manufactured efficiently. In the manufacturing method of the secondary battery 1 according to one embodiment of the present technology, the laser beam for joining the case body 110 and the sealing plates 120 and 130 can be irradiated multiple times, thereby dispersing the heat input to the case body 110 and reducing the thermal influence on the case body 110. In addition, if the laser beam is irradiated multiple times, the stroke of the laser beam can be shortened, so the joining device can be miniaturized. In the manufacturing method of the secondary battery 1 according to one embodiment of the present technology, the laser is irradiated multiple times, and both the first end and the second end of the joint 115 are made to be the starting point or the end point of welding. Thus, compared with the case where the joint 115 is formed by one joint and the first end and the second end of the joint 115 are made to be the starting point or the end point of welding and the joint state is not unified, the joint state of the first end and the second end can be unified, thereby stably forming the joint 115. In a method for manufacturing a secondary battery 1 according to one embodiment of the present technology, the first joining portion 140 and the second joining portion 141 can be formed while the shell body 110 is rotated. Therefore, compared with a structure in which the shell body 110 is stationary and the joining device moves around the shell body 110, the joining device 2 can be miniaturized, and the secondary battery 1 can be manufactured efficiently. In a manufacturing method of a secondary battery 1 according to one embodiment of the present technology, the shell body 110 is gripped by a manufacturing device to the extent that the shell body 110 can clamp the electrode body 200. When the shell body 110 is rotated for joining, the electrode body 200 can be kept stationary inside the shell body 110, thereby preventing damage to the electrode body 200. In the method for manufacturing the secondary battery 1 according to one embodiment of the present technology, by temporarily joining the case body 110 and the sealing plates 120 and 130 before joining them, positional deviation between the case body 110 and the sealing plates 120 and 130 can be suppressed when the case body 110 is rotated for joining. In the method for manufacturing the secondary battery 1 according to one embodiment of the present technology, the secondary battery 1 can be efficiently manufactured by forming the first joining portion 140 and the second joining portion 141 at the same time. 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 secondary battery, characterized in that: have: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and a shell that accommodates the electrode body, The housing comprises: a housing body having a first opening located at an end portion on a first side in a first direction, and a second opening located at an end portion on a second side opposite to the first side in the first direction; a first sealing plate for sealing the first opening; as well as a second sealing plate for sealing the second opening, The housing body has an outer peripheral surface extending around the axis of the first direction, a first end surface located at the end of the first side and extending in a direction intersecting the first direction, and a second end surface located at the end of the second side and extending in a direction intersecting the first direction. The first sealing plate has a first covering portion that covers at least a portion of the first end surface from the first direction. The second sealing plate has a second covering portion that covers at least a portion of the second end surface from the first direction. A first joint portion is formed so as to span the outer peripheral surface portion and the first covering portion, A second joining portion is formed so as to straddle the outer peripheral surface portion and the second covering portion.

2. The secondary battery according to claim 1, characterized in that: The housing body includes a joining portion extending along the first direction on the outer peripheral surface portion.

3. The secondary battery according to claim 1 or 2, characterized in that: The electrode body comprises: Main body; a first electrode sheet group electrically connected to the first electrode and located on the first side relative to the main body; and A second electrode sheet group is electrically connected to the second electrode and is located on the second side with respect to the main body.

4. The secondary battery according to claim 1 or 2, characterized in that: have: a first electrode terminal electrically connected to the first electrode and mounted on the first sealing plate; and a second electrode terminal which is electrically connected to the second electrode and is mounted on the second sealing plate.

5. The secondary battery according to claim 1 or 2, characterized in that: have: a first separator located between the electrode body and the first sealing plate; and a second separator located between the electrode body and the second sealing plate.

6. The secondary battery according to claim 1 or 2, characterized in that: The housing body has an inner peripheral surface extending around the axis in the first direction. The first sealing plate has a first portion which enters the interior of the housing body relative to the first opening and faces the inner peripheral surface of the housing body. The second sealing plate has a second portion that enters the interior of the housing body relative to the second opening and faces the inner peripheral surface of the housing body. The first joining portion and the second joining portion are welded portions.

7. A method for manufacturing a secondary battery, characterized in that: The following processes are available, namely: Preparing a shell body, wherein the shell body has a first opening portion located at an end portion of a first side in a first direction, a second opening portion located at an end portion of a second side in the first direction opposite to the first side, an outer peripheral surface portion extending around an axis in the first direction, a first end surface located at an end portion of the first side and extending in a direction intersecting the first direction, and a second end surface located at an end portion of the second side and extending in a direction intersecting the first direction; inserting an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode into the interior of the housing body; The first opening is sealed by bringing a first sealing plate into contact with the first end surface so as to cover at least a portion of the first end surface from the first direction, and performing a joining process from the outer peripheral side around the axis in the first direction to form a joining portion so as to straddle the first sealing plate and the outer peripheral surface of the housing body; and The second opening is sealed by bringing the second sealing plate into contact with the second end surface so as to cover at least a portion of the second end surface from the first direction, and performing a joining process from the outer peripheral side around the axis in the first direction to form a joining portion so as to span the second sealing plate and the outer peripheral surface portion of the shell body.

8. The method for manufacturing a secondary battery according to claim 7, characterized in that: The housing body is formed by bending a plate-shaped member into a cylindrical shape and joining both ends of the plate-shaped member bent into the cylindrical shape to each other.

9. The method for manufacturing a secondary battery according to claim 8, characterized in that: The process of joining the two ends of the plate-like member to each other includes welding by irradiating energy beams a plurality of times.

10. The method for manufacturing a secondary battery according to claim 8, characterized in that: The process of joining the two ends of the plate-like member to each other includes welding by irradiating energy beams multiple times. The welding process of irradiating the energy line multiple times has the following steps, namely: welding a first region of the housing body including the end portion on the first side; and welding the second region of the housing body including the second side end portion, In welding the first region and the second region, the end portion on the first side and the end portion on the second side serve as a start point or an end point of welding. When the end portion on the first side becomes the starting point of welding, the end portion on the second side becomes the starting point of welding, When the end portion on the first side becomes the end point of welding, the end portion on the second side becomes the end point of welding.

11. The method for manufacturing a secondary battery according to any one of claims 7 to 10, characterized in that: In the step of sealing the first opening, the process of forming the joining portion includes welding by irradiating energy beams a plurality of times.

12. The method for manufacturing a secondary battery according to claim 11, characterized in that: The welding is performed by irradiating the energy beam a plurality of times, so that the first sealing plate and the housing body are joined via the plurality of joining portions. Adjacent joining portions among the plurality of joining portions are formed so that parts of the adjacent joining portions overlap with each other.

13. The method for manufacturing a secondary battery according to claim 7 or 8, characterized in that: At least one of the step of sealing the first opening and the step of sealing the second opening includes the step of rotating the case body around an axis in the first direction.

14. The method for manufacturing a secondary battery according to claim 13, characterized in that: At least one of the step of sealing the first opening and the step of sealing the second opening includes pressing the case body until the case body is deformed so that the electrode body is sandwiched between the case bodies.

15. The method for manufacturing a secondary battery according to claim 13, characterized in that: The following processes are available, namely: Before the step of sealing the first opening, temporarily joining the first sealing plate to the housing body; and Before the step of sealing the second opening, the second sealing plate is temporarily joined to the case body.

16. The method for manufacturing a secondary battery according to claim 7 or 8, characterized in that: At least a part of the step of sealing the first opening and the step of sealing the second opening are performed simultaneously.

17. The method for manufacturing a secondary battery according to claim 7 or 8, characterized in that: The housing body has an inner peripheral surface extending around the axis in the first direction. The first sealing plate has a first portion which enters the interior of the housing body relative to the first opening and faces the inner peripheral surface of the housing body. The second sealing plate has a second portion that enters the interior of the housing body relative to the second opening and faces the inner peripheral surface of the housing body. In the step of sealing the first opening and the step of sealing the second opening, the first sealing plate and the shell body are welded, and the second sealing plate and the shell body are welded by irradiating energy lines from the outer peripheral side of the axis around the first direction.

Images