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 secondary battery, a case main body has a first opening at one end thereof and a second opening at the other end thereof, the first opening is sealed by a first sealing plate, the second opening is sealed by a second sealing plate, a first through-hole is provided in a region on the side of the second opening from the end of the electrode body on the side of the second opening, and a second through-hole is provided in the region on the side of the second opening from the end of the electrode body on the side of the second opening. The first through hole is sealed by a first sealing member. This configuration makes it possible to manufacture a secondary battery more efficiently and stably.

Description

Technical Field

[0001] The present technology relates to a secondary battery and a method for manufacturing the secondary battery. Background Art

[0002] Japanese Patent Gazette No. 4537353 discloses a square secondary battery in which an electrode group (25) is housed in a battery case (14) having openings (14a, 14b) at both ends, and electrode terminals (21, 23) are respectively mounted on covers (33, 33') for sealing the openings (14a, 14b).

[0003] By forming a rectangular battery with a positive terminal on one side of the battery case and a negative terminal on the other end, a low-height battery pack can be easily obtained. However, there is still room for further improvement in order to obtain a battery that can be manufactured efficiently and stably. Summary of the invention

[0004] An object of the present technology is to provide a secondary battery and a method for manufacturing a secondary battery that can be manufactured efficiently and stably.

[0005] The present technology provides the following secondary battery and method for manufacturing the secondary battery.

[0006] [1] A secondary battery comprising: an electrode body including a first electrode, a second electrode having a polarity different from that of the first electrode, and a separator disposed between the first electrode and the second electrode; and an outer casing accommodating the electrode body and an electrolyte, the outer casing comprising: a case body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening. A first electrode terminal electrically connected to the first electrode is provided on the first sealing plate, a second electrode terminal electrically connected to the second electrode is provided on the second sealing plate, a first electrode sheet group electrically connected to the first electrode is provided at one end of the electrode body, and a second electrode sheet group electrically connected to the second electrode is provided at the other end of the electrode body, and a first through hole is provided in a region of the shell body that is closer to the second opening than the end of the side where the second opening of the electrode body is located, and the first through hole is sealed by a first sealing component.

[0007] [2] In the secondary battery described in [1], a second through hole is provided in a region of the case body closer to the first opening than an end portion of the electrode body on the first opening side, and the second through hole is sealed by a second sealing member.

[0008] [3] In the secondary battery described in [1] or [2], when the distance between the first sealing plate and the end of the electrode body on the side where the first sealing plate is located is set to D1, and the distance between the second sealing plate and the end of the electrode body on the side where the second sealing plate is located is set to D2, there is a relationship of D2>D1.

[0009] [4] A method for manufacturing a secondary battery, the secondary battery comprising: an electrode body, the electrode body including a first electrode, a second electrode having a polarity different from that of the first electrode, and a separator arranged between the first electrode and the second electrode; and an outer body, the outer body accommodating the electrode body and an electrolyte, the outer body comprising: a shell body, the shell body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate, the first sealing plate sealing the first opening; and a second sealing plate, the second sealing plate sealing the second opening, the first sealing plate being provided with a first electrode terminal electrically connected to the first electrode, and the second sealing plate being provided with a first electrode terminal electrically connected to the first electrode. The sealing plate is provided with a second electrode terminal electrically connected to the second electrode, a first electrode sheet group electrically connected to the first electrode is provided at one end of the electrode body, and a second electrode sheet group electrically connected to the second electrode is provided at the other end of the electrode body, and the shell body is provided with a first through hole in a region closer to the second opening than the end of the side where the second opening of the electrode body is located, and the first through hole is sealed by a first sealing component, wherein the manufacturing method of the secondary battery having the above structure has the following steps, namely: a step of injecting electrolyte into the outer body from the first through hole; and a step of sealing the first through hole by the first sealing component.

[0010] 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

[0011] Figure 1 It is a front view of a secondary battery.

[0012] Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0013] Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery.

[0014] Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0015] Figure 5 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0016] Figure 6 It is a front view showing a negative electrode original plate before forming a negative electrode plate.

[0017] Figure 7 yes Figure 6 VII-VII cross-sectional view of the negative electrode original plate shown.

[0018] Figure 8 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0019] Fig. 9 It is a front view showing a positive electrode original plate before forming a positive electrode plate.

[0020] Fig.10 yes Fig. 9 XX cross-sectional view of the positive electrode original plate shown.

[0021] Fig.11 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0022] Fig.12 It is a diagram showing an electrode body and a current collector taken out from a secondary battery.

[0023] Fig.13 It is a diagram showing the connection structure between the negative electrode sheet group and the negative electrode current collector.

[0024] Fig.14 yes Fig.13 Front view of the connection structure shown.

[0025] Fig.15 yes Fig.13 A cross-sectional view of the connection structure shown.

[0026] Fig.16 It is a diagram showing the step of inserting the electrode body into the case body.

[0027] Fig.17 It is a diagram showing a step of providing a separator between the first sealing plate and the electrode body.

[0028] Fig.18 It is a cross-sectional view showing a state where a separator is provided between the first sealing plate and the electrode body.

[0029] Fig.19 It is a diagram showing a modified example of the spacer.

[0030] Fig. 20 This is a diagram showing an example of a mechanism for pressing the electrode assembly via the first sealing plate and the separator.

[0031] Fig.21 It means viewing from the Z axis direction Fig. 20A diagram showing the state of the mechanism.

[0032] Fig. 22 This is a three-dimensional diagram of another type of spacer.

[0033] Fig.23 This is a three-dimensional diagram of another type of spacer.

[0034] Fig.24 This is a three-dimensional diagram of another type of spacer.

[0035] Fig.25 It is a flowchart showing each process of the manufacturing method of a secondary battery. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.).

[0040] In this specification, "battery" is not limited to lithium-ion batteries, and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode. In addition, "electrode plate" may be collectively referred to as positive electrode plate and negative electrode plate.

[0041] (Overall structure of the battery)

[0042] 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 1 The 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.

[0043] 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.

[0044] like Figure 1 to Figure 5 As shown, the secondary battery 1 includes an outer casing 100 , an electrode body 200 , and a current collector 300 . The outer casing 100 includes a case body 110 , a first sealing plate 121 , and a second sealing plate 122 .

[0045] In this application specification, there is Figure 1 to Figure 5 The X-axis direction (first direction) shown is called the "width direction" of the secondary battery 1 or the shell body 110. Similarly, the Y-axis direction (second direction) is called the "thickness direction" of the secondary battery 1 or the shell body 110. Similarly, the Z-axis direction (third direction) is called the "height direction" of the secondary battery 1 or the shell body 110. In addition, in the description of this disclosure, the Z-axis direction is consistent with the direction of the sky and the earth. Therefore, in Figure 1 In the secondary battery 1 shown in the figure, the upper side in the figure is vertically upward, and the lower side in the figure is vertically downward. Figure 2 Indicates the state viewed from the bottom.

[0046] 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-axis 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.

[0047] 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.

[0048] like Figure 1 , Figure 2As shown in FIG. 1 , a first sealing plate 121 and a second sealing plate 122 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 joint portion 110A shown in the example in FIG. 1 (e.g., laser welding) to each other. The corner of the "square tube shape" may also have an R shape.

[0049] In the present embodiment, the case body 110 is formed to be longer in the width direction (X-axis direction) of the secondary battery 1 than in the thickness direction (Y-axis direction) and the height direction (Z-axis direction) of the secondary battery 1. Therefore, a pair of opposing first walls 110Y is defined by a surface on one side and a surface on the opposite side, and a pair of opposing second walls 110Z is defined by a surface on the upper side and a surface on the lower side in the figure, and the area of ​​the pair of first walls 110Y is larger than the area of ​​the pair of second walls 110Z.

[0050] The dimension (width) of the shell body 110 in the X-axis direction is preferably 30 cm or more. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z-axis direction is preferably 20 cm or less, more preferably 15 cm or less, and further preferably 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0051] like Figure 3 As shown, a first opening 111 is provided at one end of the housing body 110. The first opening 111 is sealed by a first sealing plate 121. A negative terminal 131 (first electrode terminal) and an exhaust valve 151 are provided on the first sealing plate 121. The positions of the negative terminal 131 and the exhaust valve 151 can be changed appropriately. The first opening 111 and the first sealing plate 121 have a substantially rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction.

[0052] like Figure 4 As shown, a second opening 112 is provided at one end of the housing body 110. The second opening 112 is sealed by a second sealing plate 122. A positive terminal 132 (second electrode terminal) and an exhaust valve 152 are provided on the second sealing plate 122. The positions of the positive terminal 132 and the exhaust valve 152 can be changed appropriately. The second opening 112 and the second sealing plate 122 have a substantially rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction.

[0053] The first sealing plate 121 and the second sealing plate 122 are made of metal. Specifically, the first sealing plate 121 and the second sealing plate 122 are made of aluminum, aluminum alloy, iron, iron alloy, or the like.

[0054] The negative electrode terminal 131 is electrically connected to the negative electrode of the electrode body 200 . The positive electrode terminal 132 is electrically connected to the positive electrode of the electrode body 200 .

[0055] The negative electrode terminal 131 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 131 .

[0056] The positive electrode terminal 132 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy.

[0057] The exhaust valves 151 and 152 rupture when the pressure in the outer casing 100 reaches a predetermined value or more, and exhaust the gas in the outer casing 100 to the outside.

[0058] 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 electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets provided on each positive plate may also be stacked to form a positive electrode sheet group, and the negative electrode sheets provided on each negative plate may also be stacked to form a negative electrode sheet group.

[0059] In the present embodiment, a first through hole 141 and a second through hole 142 are provided on the second wall 110Z side of the upper surface side of the housing body 110 shown in the figure. The first through hole 141 is sealed by a first sealing member 701. The second through hole 142 is sealed by a second sealing member 702. The first sealing member 701 and the second sealing member 702 can be fixed to the housing body 110 by riveting, for example, using blind rivets or other metal members. The first sealing member 701 and the second sealing member 702 can also be fixed to the housing body 110 by welding.

[0060] Although it is also described in the "manufacturing process of the secondary battery 1" described later, when the first through hole 141 is used as an injection hole for the electrolyte, the second through hole 142 functions as a gas (air) discharge hole in the housing body 110. On the other hand, when the second through hole 142 is used as an injection hole for the electrolyte, the first through hole 141 functions as a gas (air) exhaust hole in the housing body 110.

[0061] like Figure 5 As shown, the outer casing 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the outer casing 100 so that the winding axis thereof is parallel to the X-axis direction.

[0062] Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are housed together inside an insulating sheet 600 described later and arranged in the outer casing 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.

[0063] The electrode body 200 includes a negative electrode sheet group 210A (first electrode sheet group) provided at an end (first end) on the side of the first sealing plate 121, and a positive electrode sheet group 220A (second electrode sheet group) provided at an end (second end) on the side of the second sealing plate 122. The negative electrode sheet group 210A and the positive electrode sheet group 220A are connected to the negative electrode and the positive electrode of the electrode body 200, respectively. The negative electrode sheet group 210A and the positive electrode sheet group 220A are formed to protrude from the main body of the electrode body 200 (the part formed by stacking the positive electrode plate and the negative electrode plate via the separator) toward the first sealing plate 121 and the second sealing plate 122. As a result, the main surfaces of the negative electrode sheet group 210A and the positive electrode sheet group 220A are arranged in a direction opposite to a pair of first walls 110Y, and the end side surfaces of each are arranged in a direction opposite to a pair of second walls 110Z.

[0064] The current collector 300 includes a negative electrode current collector 310 (first current collector) and a positive electrode current collector 320 (second current collector). The negative electrode current collector 310 and the positive electrode current collector 320 are each formed of a plate-like member. The electrode body 200 is electrically connected to the negative electrode terminal 131 and the positive electrode terminal 132 via the current collector 300 .

[0065] The negative electrode current collector 310 is disposed on the first sealing plate 121 via a resin insulating member. The negative electrode current collector 310 is electrically connected to the negative electrode sheet group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, metal), such as copper or a copper alloy.

[0066] The positive electrode collector 320 is arranged on the second sealing plate 122 via an insulating member made of resin. The positive electrode collector 320 is electrically connected to the positive electrode sheet group 220A and the positive terminal 132. The positive electrode collector 320 is composed of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode sheet group 220A can also be electrically connected to the second sealing plate 122 directly or via the positive electrode collector 320. In this case, the second sealing plate 122 can also serve as the positive terminal 123.

[0067] When the distance between the first sealing plate 121 and the end of the electrode body 200 on the first sealing plate 121 side is set to D1, and the distance between the second sealing plate 122 and the end of the electrode body 200 on the second sealing plate 122 side is set to D2, there is a relationship of D2>D1. Here, the end 200t1 on the first sealing plate 121 side of the electrode body 200 refers to the end of the separator, and similarly, the end 200t2 on the second sealing plate 122 side of the electrode body 200 refers to the end of the separator.

[0068] Here, the separator is arranged between the positive electrode and the negative electrode, and the width of the separator (in the X direction in the figure) is larger than the width of the negative electrode plate 210 and the positive electrode plate 220 constituting the electrode body 200 described later, so the end of the separator protrudes from the ends of the negative electrode plate 210 and the positive electrode plate 220. Therefore, the end of the separator refers to the end of the separator protruding from the ends of the negative electrode plate 210 and the positive electrode plate 220. In addition, the negative electrode sheet 210B protruding from the negative electrode plate 210 and the positive electrode sheet 220B protruding from the positive electrode plate 220 are not included in the width of the negative electrode plate 210 and the positive electrode plate 220 constituting the electrode body 200.

[0069] In this way, the space between the electrode body 200 and the sealing plate is larger on the second sealing plate 122 side than on the first sealing plate 121 side. Therefore, when used as an injection hole for the electrolyte, it is preferred to use the first through hole 141 on the second sealing plate 122 side, which is not opposite to the electrode body 200, as an injection hole for the electrolyte. Therefore, it is preferred that the second through hole 142 on the first sealing plate 121 side is used as an exhaust hole for the gas (air) in the housing body 110. In addition, the second through hole 142 may also be used as an injection hole for the electrolyte.

[0070] The first through hole 141 and the second through hole 142 are preferably provided in the space between the electrode body 200 and the sealing plate where the entire hole opening does not face the electrode body 200 , but a portion of the hole opening may be provided in the space between the electrode body 200 and the sealing plate.

[0071] It is not necessary to provide both the first through hole 141 and the second through hole 142 . By providing at least the first through hole 141 , it can be used as an electrolyte injection hole and also as a gas (air) exhaust hole in the exterior body 100 .

[0072] (Structure of Electrode Body 200)

[0073] 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 8It is a front view showing the negative electrode original plate 210S.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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 210B formed by the negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 210B are stacked to form a negative electrode sheet group 210A. The positions of the plurality of negative electrode sheets 210B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the negative electrode sheet group 210A is connected to the negative electrode collector 310. In addition, the shape of the negative electrode sheet 210B is not limited to Figure 8 The shape illustrated in .

[0079] Fig. 9 2 is a front view showing a positive electrode original plate 220S before forming a positive electrode plate 220 (second electrode). Fig.10 yes Fig. 9 The XX cross-sectional view of the positive electrode original plate 220S shown in FIG. Fig.11 1 is a front view showing a positive electrode plate 220 formed of a positive electrode original plate 220S.

[0080] The positive electrode plate 220 is manufactured by processing the positive electrode original plate 220S. Fig. 9 and Fig.10 As shown, the positive electrode original plate 220S includes a positive electrode core 221, a positive electrode active material layer 222, and a positive electrode protective layer 223. The positive electrode core 221 is an aluminum foil or an aluminum alloy foil.

[0081] The positive electrode core body 221 has a positive electrode active material layer 222 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 222 is formed on the positive electrode core body 221 by applying a positive electrode active material layer slurry using a die coater.

[0082] 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.

[0083] The positive electrode protection layer 223 is in contact with the positive electrode core 221 and is formed at one end of the positive electrode active material layer 222 in the width direction. The positive electrode protection layer 223 is formed on the positive electrode core 221 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 223 has a resistance greater than that of the positive electrode active material layer 222.

[0084] 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.

[0085] The positive electrode core 221 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 222 and the positive electrode protective layer 223. Furthermore, the positive electrode original plate 220S including the positive electrode core 221, the positive electrode active material layer 222 and the positive electrode protective layer 223 is formed by compressing the positive electrode active material layer 222. The positive electrode plate 220 is formed by cutting the positive electrode original plate 220S into a predetermined shape. The positive electrode original plate 220S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0086] like Fig.11As shown, at one end in the width direction of the positive plate 220 formed by the positive original plate 220S, a plurality of positive electrode sheets 220B formed by the positive electrode core 221 are provided. When the positive plate 220 is wound, the plurality of positive electrode sheets 220B are stacked to form a positive electrode sheet group 220A. The positions of the plurality of positive electrode sheets 220B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the positive electrode sheet group 220A is connected to the positive electrode collector 320. In addition, the shape of the positive electrode sheet 220B is not limited to Fig.11 The shape illustrated in .

[0087] A positive electrode protection layer 223 is provided at the root of each of the plurality of positive electrode sheets 220B. The positive electrode protection layer 223 need not necessarily be provided at the root of the positive electrode sheet 220B. In addition, the thickness of the positive electrode protection layer 223 is preferably smaller than the thickness of the positive electrode active material layer 222 .

[0088] In a typical example, the thickness of the negative electrode sheet 210B (one sheet) is smaller than the thickness of the positive electrode sheet 220B (one sheet). In this case, the thickness of the negative electrode sheet group 210A is smaller than the thickness of the positive electrode sheet group 220A.

[0089] (Connection Structure of Electrode Body 200 and Current Collector 300)

[0090] Fig.12 FIG. 2 is a diagram showing an electrode body 200 and a current collector 300 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.12 In 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.

[0091] The negative electrode sheet group 210A is joined to the negative electrode collector 310 at the joining portion 310A, and the positive electrode sheet group 220A is joined to the positive electrode collector 320 at the joining portion 320A. The joining portions 310A and 320A can be formed by, for example, ultrasonic welding, resistance welding, laser welding, riveting, or the like.

[0092] Fig.13 It is a diagram showing the connection structure between the negative electrode sheet group 210A and the negative electrode current collector 310 . Fig.14 , Fig.15 They are Fig.13 The front view and cross-sectional view of the connection structure shown.

[0093] like Figure 13 to Figure 15As shown, the negative electrode current collector 310 is connected to the negative electrode terminal 131 between the electrode body 200 and the first sealing plate 121. The negative electrode current collector 310 includes a first conductive member 311 and a second conductive member 312. The first conductive member 311 and the second conductive member 312 are joined at a joint 313.

[0094] The negative electrode sheet group 210A is joined to the first conductive member 311 of the negative electrode current collector 310 at the joint 310A. The first conductive member 311 is connected to the second conductive member 312 at the joint 313. The joint 313 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, riveting, or the like.

[0095] The first conductive member 311 and the second conductive member 312 are attached to the inner surface side of the first sealing plate 121 via the resin insulating member 410. The insulating member 410 is provided so as to reach the inner surface side from the outer surface side of the first sealing plate 121 via the through hole provided in the first sealing plate 121. In addition, the insulating member 410 may be composed of a plurality of members including a member disposed between the negative electrode terminal 131 and the first sealing plate 121, and a member disposed between the first conductive member 311 and the second conductive member 312 and the first sealing plate 121.

[0096] The negative terminal 131 is mounted on the first sealing plate 121 via an insulating member 410A made of resin. The negative terminal 131 is configured to be exposed on the outside of the first sealing plate 121 and reach the second conductive member 312 of the negative electrode collector 310 provided on the inner surface side of the first sealing plate 121. The negative terminal 131 and the second conductive member 312 can be connected, for example, by ultrasonic bonding, resistance welding, laser welding, riveting, etc. In the present embodiment, a through hole is provided in the second conductive member 312, the negative terminal 131 is inserted into the through hole, and after the negative terminal 131 is riveted on the second conductive member 312, the riveted portion and the second conductive member 312 are welded at the joint 131A, thereby connecting the negative terminal 131 to the second conductive member 312.

[0097] As the assembly order of each component, first, the negative terminal 131 and the second conductive component 312 are mounted on the first sealing plate 121 together with the insulating components 410 and 410A. Next, the first conductive component 311 connected to the electrode body 200 is mounted on the second conductive component 312. At this time, the first conductive component 311 is arranged on the insulating component 410 in a manner that a part of the first conductive component 311 overlaps with the second conductive component 312. Next, the first conductive component 311 and the second conductive component 312 are welded and connected at the joint 313. In addition, the insulating components 410 and 410A may also be composed of one component.

[0098] The negative electrode terminal 131 may be electrically connected to the first sealing plate 121 . In addition, the first sealing plate 121 may also function as the negative electrode terminal 131 .

[0099] In addition, Figure 13 to Figure 15 In FIG. 1 , the negative electrode current collector 310 is exemplified as being composed of two members (the first conductive member 311 and the second conductive member 312 ), but the negative electrode current collector 310 may be composed of a single member.

[0100] exist Figure 13 to Figure 15 , 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.

[0101] (Step of Inserting Electrode Body 200)

[0102] Fig.16 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.16 As shown, an insulating sheet 600 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0103] The insulating sheet 600 may be made of, for example, resin. More specifically, the insulating sheet 600 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0104] The insulating sheet 600 does not necessarily need to cover the entire surface of the electrode body 200. Preferably, the insulating sheet 600 covers 50% or more of the outer surface of the electrode body, and more preferably covers 70% or more of the area. Preferably, the insulating sheet 600 covers the entirety of at least four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for the two surfaces each having the negative electrode sheet group 210A and the positive electrode sheet group 220A.

[0105] Fig.17 This is a diagram showing a step of placing the separator 510 between the first sealing plate 121 and the electrode body 200 . Fig.18 It is a cross-sectional view showing a state where the separator 510 is arranged between the first sealing plate 121 and the electrode body 200 .

[0106] like Fig.17 , Fig.18 As shown, the negative electrode sheet group 210A from the electrode body 200 toward the first sealing plate 121 is bent from the center of the first sealing plate 121 in the Y-axis direction toward the end, and then folded back toward the center. A separator 510 is provided to accommodate the bent negative electrode sheet group 210A (bent portion).

[0107] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 are each slid along the Y-axis direction from the end side toward the center side of the first sealing plate 121 and engaged with each other. As a result, the spacer 510 is fixed to the first sealing plate 121 via the insulating member 410, and the stability of the position of the spacer 510 is increased.

[0108] like Fig.18 As shown, the separator 510 forms an internal space for accommodating the negative electrode current collector 310, and the front end portion of the negative electrode sheet group 210A is also accommodated in the internal space of the separator 510. The separator 510 has a hole portion for allowing the negative electrode sheet group 210A to pass through.

[0109] The material of the separator 510 is not particularly limited, but an insulating material such as resin is preferably used. More specifically, a sheet made of polyolefin (PO) is preferably used. Insulating sheet 600 may be interposed between separator 510 and electrode body 200 .

[0110] Refer again Fig.16 In the manufacturing method of the secondary battery 1 of the present embodiment, after the negative electrode terminal 131 is electrically connected to the negative electrode sheet group 210A, the electrode body 200 is inserted into the case body 110 from the end side of the positive electrode sheet group 220A side through the first opening 111. When the electrode body 200 is inserted to a predetermined position of the case body 110, the positive electrode sheet group 220A protrudes from the second opening 112 of the case body 110 to the outside of the case body 110. Thus, after the electrode body 200 is inserted into the case body 110, the positive electrode terminal 132 and the positive electrode sheet group 220A can be connected.

[0111] When the negative electrode terminal 131 mounted on the first sealing plate 121 is electrically connected to the negative electrode sheet group 210A after the electrode body 200 is inserted into the case body 110, the negative electrode sheet group 210A is required to have a length that allows the negative electrode sheet group 210A of the electrode body 200 housed in the case body 110 to sufficiently protrude to the outside of the case body 110. By electrically connecting the negative electrode terminal 131 mounted on the first sealing plate 121 to the negative electrode sheet group 210A before the electrode body 200 is inserted into the case body 110, the length of the negative electrode sheet group 210A can be shortened compared to the case where the electrode body 200 is installed after being inserted into the case body 110. As a result, the volume occupancy rate of the negative electrode plate 210 and the positive electrode plate 220 in the internal space of the case body 110 can be increased.

[0112] In addition, Fig.16In the example, after the separator 510 for accommodating the bent portion of the negative electrode sheet group 210A is arranged, the electrode body 200 is inserted into the shell body 110. In this way, the bent portion of the negative electrode sheet group 210A can be protected during the insertion process of the electrode body 200. Preferably, an opening 510h for passing the electrolyte is provided in the separator 510 at a position opposite to the second through hole 142. The shape of the opening 510h is not limited to a circle, and any shape is acceptable as long as it is a shape that allows the electrolyte to pass.

[0113] In addition, Fig.16 In the example, the electrode body 200 is inserted into the case body 110 in a state where the electrode body 200 is covered by the insulating sheet 600 . This can prevent the electrode body 200 from being damaged when being inserted into the case body 110 .

[0114] During the insertion process of the electrode body 200, the case body 110 can be held at a predetermined angle. As one example, the electrode body 200 is preferably inserted in a state where the case body 110 is held so that the X-axis direction (the width direction of the case body 110) intersects with the horizontal direction at an angle of less than ±45°. For example, the case body 110 is tilted so that the upper end of the first opening 111 into which the electrode body 200 is inserted is located above the upper end of the second opening 112 in the vertical direction, so that the electrode body 200 can be inserted into the case body 110.

[0115] The step of inserting the electrode body 200 is not limited to a method of pressing the electrode body 200 from the first opening 111 side, and may be a method of pulling the electrode body 200 from the second opening 112 side, for example.

[0116] When the positive electrode sheet group 220A is observed from the first through hole 141 provided in the second wall 110Z, the positive electrode sheet group 220A can be bent to avoid the first through hole 141. This is because the injectability of the electrolyte can be improved. Similarly, when the negative electrode sheet group 210A is observed from the second through hole 142 provided in the second wall 110Z, the negative electrode sheet group 210A can be bent to avoid the second through hole 142. With this structure, in the manufacturing process of the secondary battery 1 described later, the injectability of the electrolyte can be improved.

[0117] Fig.19 5 is a diagram showing a modified example of the spacer 510. Figure 16 to Figure 18 In the example of FIG. 1 , a spacer 510 is disposed at a portion of the first sealing plate 121 in the height direction (Z-axis direction). Fig.19As shown, the separator 510 may be arranged over substantially the entire area in the height direction of the first sealing plate 121. In this case, the separator 510 may also have a portion protruding toward the electrode body 200 side more than the vicinity of the negative electrode sheet group 210A (the second area) at a position separated from the negative electrode sheet group 210A in the Z-axis direction (the first area). A step difference (preferably a step difference of 1 mm or more) may also be formed at the boundary between the first area and the second area. In this way, damage to the negative electrode sheet group 210A caused when the electrode body 200 is inserted into the case body 110 can be suppressed.

[0118] (Mechanism for pressing the electrode body)

[0119] Fig. 20 This is a diagram showing an example of a mechanism for pressing the electrode body 200 via the first sealing plate 121 and the separator 510A. Fig.21 It means viewing from the Z axis direction Fig. 20 The spacer 510A is a modified example of the spacer 510 described above.

[0120] like Fig. 20 , Fig.21 As shown, the separator 510A is arranged in a position avoiding the negative electrode sheet group 210A and the negative electrode collector 310 (a position separated from the negative electrode sheet group 210A and the negative electrode collector 310) in the height direction (Z-axis direction) of the first sealing plate 121 and the electrode body 200. More specifically, the separator 510A is arranged in two positions in a manner of clamping the negative electrode sheet group 210A in the Z-axis direction. Preferably, the separator 510A presses the portion of the electrode body 200 where the negative electrode sheet group 210A is not provided. It is particularly preferred to press the portion of the diaphragm that protrudes from the end of the negative electrode plate 210. The separator 510A may also be arranged only on one side of the negative electrode sheet group 210A in the Z-axis direction. The separator 510A may be fixed to the first sealing plate 121 and / or the electrode body 200, for example, by bonding, welding, tape bonding, etc. In addition, the separator 510A may also be in contact with the negative electrode sheet group 210A.

[0121] It is preferable to provide a through hole, a cutout, a slit, etc. in the spacer 510A at a position opposite to the first through hole 141. In addition, it is preferable to provide a through hole, a cutout, a slit, etc. in the spacer 510A at a position opposite to the exhaust valve 151. Thus, the function of the first through hole 141 or the exhaust valve 151 can be more reliably ensured.

[0122] exist Fig. 20 , Fig.21In the example, the electrode body 200 is inserted into the case body 110 by pressing the electrode body 200 via the separator 510A. The electrode body 200 may be further inserted by holding the electrode body 200 at the beginning of the insertion process of the electrode body 200 and pressing the electrode body 200 via the separator 510A after a part of the electrode body 200 is inserted into the case body 110.

[0123] Instead of the above-mentioned separator, a separator fixed to the electrode body 200 may be provided. The separator is fixed to the electrode body 200 by, for example, sticking with a tape.

[0124] In addition, from the perspective of protecting the positive electrode sheet group 220A, the separator 510 and the separator 510A may be disposed on the positive electrode sheet group 220A side. In the separator disposed on the positive electrode sheet group 220A side, it is also preferred to provide an opening for passing the electrolyte at a position opposite to the first through hole 141. The shape of the opening may be any shape as long as it allows the electrolyte to pass.

[0125] Here, refer to Figure 22 to Figure 24 Other types of spacers are shown in the drawings. Fig. 22 is a three-dimensional diagram of another type of spacer 510B. Fig.23 is a three-dimensional diagram of another type of spacer 510C. Fig.24 This is a perspective view of another type of spacer 510D.

[0126] Fig. 22 The separator 510B shown has a rectangular opening 510h1 on the side facing the electrode body 200. In the case of the separator 510B, the opening 510h1 is positioned at a position not facing the first through hole 141 (or the second through hole 142).

[0127] Fig.23 The separator 510C shown has an inclined slit-shaped opening 510h2 on the side facing the electrode body 200. When the slit-shaped opening 510h2 is provided, a sufficient opening area can be ensured, and the flow path area required for degassing and liquid injection can be ensured, which has the advantage of preventing the injected solvent from accumulating.

[0128] Fig.24 The separator 510D shown is provided with a rectangular opening 510h3 on the side opposite to the first through hole 141 (or the second through hole 142). The opening 510h3 is arranged at a position perpendicular to the bending direction of the electrode sheet. As a result, the curling of the diaphragm or the damage of the electrode (including the sheet) caused by the influence of the injection can be prevented, the pressing when the electrode body is inserted can be made uniform, and the bent electrode sheet can be prevented from being squeezed out of the space in the separator.

[0129] The outer shape, opening position and shape of the separator are not limited to the above-mentioned separator, but by appropriately setting openings in the separator configured for the purpose of protecting the positive electrode sheet group 220A and the negative electrode sheet group 210A, it is possible to suppress damage to the electrode body, suppress unwanted short circuits, and suppress reduction in electrolyte injection properties.

[0130] (Manufacturing process of secondary battery 1)

[0131] Fig.25 1 is a flow chart showing each step of the method for manufacturing the secondary battery 1. Fig.25 As shown, in S10, the shell body 110 is prepared. Next, in S20, the electrode body 200 is made. In S30, the electrode terminals provided on the first sealing plate 121 and the second sealing plate 122 are electrically connected to the electrode sheet group of the electrode body 200. At this time, first, the negative terminal 131 is electrically connected to the negative electrode sheet group 210A (S31), and then, the separator 510 is arranged between the first sealing plate 121 on the negative electrode side and the electrode body 200 (S40), and then the electrode body 200 is inserted into the shell body 110 (S50). At this time, the positive electrode sheet group 220A protrudes from the second opening 112 of the shell body 110 to the outside of the shell body 110. After the electrode body 200 is inserted into the shell body 110, the positive terminal 132 is electrically connected to the positive electrode sheet group 220A (S32).

[0132] In this embodiment, an example is described in which the negative terminal 131 is connected to the negative electrode sheet group 210A (S31), the electrode body 200 is inserted (S50), and the positive terminal 132 is connected to the positive electrode sheet group 220A (S32). However, the scope of the present technology is not limited to this, and sometimes the process is carried out in the order of connecting the positive terminal 132 to the positive electrode sheet group 220A (S32), inserting the electrode body 200 (S50), and connecting the negative terminal 131 to the negative electrode sheet group 210A (S31).

[0133] After the connection between the electrode terminal and the electrode sheet group (S30) is completed, the first opening 111 and the second opening 112 are sealed (S60) by the first sealing plate 121 and the second sealing plate 122. The sealing process by the first sealing plate 121 and the second sealing plate 122 is performed by, for example, laser welding.

[0134] The process (S61) of sealing the first opening 111 using the first sealing plate 121 on the negative electrode side can be performed after the process (S50) of inserting the electrode body 200 into the shell body 110, and the process (S62) of sealing the second opening 112 using the second sealing plate 122 on the positive electrode side can be performed after the process (S32) of electrically connecting the positive terminal 132 to the positive electrode sheet group 220A.

[0135] Therefore, for example, the step (S61) of sealing the first opening 111 with the first sealing plate 121 may be performed before the step (S32) of electrically connecting the positive electrode terminal 132 to the positive electrode sheet group 220A, or the step (S61) of sealing the first opening 111 with the first sealing plate 121 may be performed after the step (S62) of sealing the second opening 112 with the second sealing plate 122. Furthermore, at least a part of the steps (S61, S62) of sealing with the first sealing plate 121 and the second sealing plate 122 may be performed simultaneously.

[0136] Next, a process (S70) of injecting electrolyte into the outer body 100 from the first through hole 141 is performed. It is preferred to use the first through hole 141 on the side of the second sealing plate 122 where the space between the electrode body 200 and the sealing plate is larger as an injection port for the electrolyte. On the other hand, since the second through hole 142 is provided on the opposite side, it is preferred to use the second through hole 142 as a vent for the gas (air or nitrogen, etc.) in the outer body 100. Thus, it is possible to improve the injection property of the electrolyte into the outer body 100.

[0137] By injecting the electrolyte into the shell body 110 from the first through hole 141 in the shell body 110, which is arranged in an area closer to the second opening 112 side than the end of the second opening 112 side of the electrode body 200, it is possible to inject the electrolyte from the area of ​​the shell body 110 that is not opposite to the electrode body 200 (except for the sheet group), so the injection property is improved. In addition, by providing the first through hole 141 in the shell body 110, it is easy to inject the electrolyte into the shell body 110 when the long side direction of the shell body 110 is oriented in the horizontal direction or when the long side direction of the shell body 110 is oriented in a state close to the horizontal direction. As a result, damage to the electrode body 200 can be more effectively suppressed. Alternatively, dripping can also be suppressed.

[0138] When injecting the electrolyte into the outer casing 100, the outer casing 100 is preferably placed on a horizontal plane so that the second wall 110Z provided with the first through hole 141 is on the upper side. On the other hand, the outer casing 100 may be tilted (the second through hole 142 is on the lower side) so that the second wall 110Z is at an angle of 45 degrees or less, preferably at an angle of 30 degrees or less, and more preferably at an angle of 15 degrees or less, and the electrolyte may be injected into the outer casing 100. Thus, the injection property of the electrolyte into the outer casing 100 can be improved.

[0139] After the electrolyte is injected into the outer body 100, the first through hole 141 is sealed by the first sealing member 701 (first sealing step), and the second through hole 142 is sealed by the second sealing member 702 (second sealing step). Either the first sealing step or the second sealing step may be performed first. The first sealing member 701 and the second sealing member 702 are fixed to the housing body 110 by riveting, for example, using blind rivets or other metal parts. Alternatively, the first sealing member 701 and the second sealing member 702 are fixed to the housing body 110 by welding.

[0140] Here, after performing one of the first sealing step and the second sealing step, a charging step of charging the electrode body 200 is performed, and after the charging step, the other of the first sealing step and the second sealing step is performed. After the through-holes on one side are sealed, charging is performed to discharge the generated gas to the outside of the outer casing 100. By sealing the through-holes on the other side thereafter, expansion of the outer casing 100 can be suppressed.

[0141] (summary)

[0142] The secondary battery 1 and the method for manufacturing the secondary battery 1 according to the present embodiment can be summarized as follows.

[0143] The secondary battery 1 includes an electrode body 200 including a negative electrode original plate 210S, a positive electrode original plate 220S having a different polarity from the negative electrode original plate 210S, and a separator disposed between the negative electrode original plate 210S and the positive electrode original plate 220S; and an outer casing 100 accommodating the electrode body 200 and an electrolyte. The outer casing 100 includes a case body 110 having a first opening 111 at one end thereof and a second opening 112 at the other end thereof; a first sealing plate 121 for sealing the first opening 111; and a second sealing plate 122 for sealing the second opening 112. A negative terminal 131 electrically connected to the negative electrode original plate 210S is provided on the first sealing plate 121, and a positive terminal 132 electrically connected to the positive electrode original plate 220S is provided on the second sealing plate 122. A negative electrode sheet group 210A electrically connected to the negative electrode original plate 210S is provided at one end of the electrode body 200, and a positive electrode sheet group 220A electrically connected to the positive electrode original plate 220S is provided at the other end of the electrode body 200. The case body 110 is provided with a first through hole 141 in a region closer to the second opening 112 side than the end of the electrode body 200 on the second opening 112 side, and the first through hole 141 is sealed by a first sealing member 701.

[0144] In the secondary battery 1 according to one example, a second through hole 142 is provided in a region of the case body 110 that is closer to the first opening 111 than the end of the electrode body 200 on the first opening 111 side, and the second through hole 142 is sealed by a second sealing member 702. When the secondary battery 1 is manufactured, the first through hole 141 can be used as an electrolyte injection port, and the second through hole 142 can be used as a gas (air) exhaust hole in the outer body 100.

[0145] Regarding the secondary battery 1 involved in one example, when the distance between the first sealing plate 121 and the end of the electrode body 200 on the first sealing plate 121 side is set to D1, and the distance between the second sealing plate 122 and the end of the electrode body 200 on the second sealing plate 122 side is set to D2, there is a relationship of D2>D1. The space between the electrode body 200 and the sealing plate is larger on the second sealing plate 122 side than on the first sealing plate 121 side, so it is preferable to use the first through hole 141 located on the second sealing plate 122 side as a liquid injection hole for the electrolyte.

[0146] The method for manufacturing the secondary battery 1 having the above-described structure includes the steps of injecting an electrolyte solution into the outer casing 100 from the first through hole 141 and sealing the first through hole 141 with the first sealing member 701 .

[0147] (Function and Effect)

[0148] According to the secondary battery 1 of this embodiment, the secondary battery 1 can be manufactured efficiently and the liquid injection property can be improved. For example, for the secondary battery 1, by arranging the long side direction of the outer casing 100 in a horizontal manner, the liquid injection property of the electrolyte into the outer casing 100 can be improved. As a result, the secondary battery 1 can be manufactured more efficiently and stably.

[0149] 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, a second electrode having a polarity different from that of the first electrode, and a separator disposed between the first electrode and the second electrode; as well as an outer casing that contains the electrode body and the electrolyte, The outer casing comprises: a housing body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate for sealing the first opening; as well as a second sealing plate for sealing the second opening, The first sealing plate is provided with a first electrode terminal electrically connected to the first electrode. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode. A first electrode sheet group electrically connected to the first electrode is provided at one end of the electrode body. A second electrode sheet group electrically connected to the second electrode is provided at the other end of the electrode body. The case body is provided with a first through hole in a region closer to the second opening than an end of the electrode body on the side where the second opening is located. The first through hole is sealed by a first sealing member.

2. The secondary battery according to claim 1, characterized in that: A second through hole is provided in a region of the case body that is closer to the first opening than an end of the electrode body on the side where the first opening is located. The second through hole is sealed by a second sealing member.

3. The secondary battery according to claim 1 or 2, characterized in that: When D1 is a distance between the first sealing plate and the end of the electrode body where the first sealing plate is located, and D2 is a distance between the second sealing plate and the end of the electrode body where the second sealing plate is located, a relationship of D2>D1 is established.

4. A method for manufacturing a secondary battery, characterized in that: The secondary battery has: an electrode body including a first electrode, a second electrode having a polarity different from that of the first electrode, and a separator disposed between the first electrode and the second electrode; as well as an outer casing that contains the electrode body and the electrolyte, The outer casing comprises: a housing body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate for sealing the first opening; as well as a second sealing plate for sealing the second opening, The first sealing plate is provided with a first electrode terminal electrically connected to the first electrode. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode. A first electrode sheet group electrically connected to the first electrode is provided at one end of the electrode body. A second electrode sheet group electrically connected to the second electrode is provided at the other end of the electrode body. The case body is provided with a first through hole in a region closer to the second opening than an end of the electrode body on the side where the second opening is located. The first through hole is sealed by a first sealing member. in, The method for manufacturing the secondary battery having the above structure comprises the following steps, namely: a step of injecting the electrolyte solution into the outer casing through the first through hole; and a step of sealing the first through hole with the first sealing member.

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