Secondary battery and method for manufacturing same

Abstract

The invention provides a secondary battery and a manufacturing method thereof. In a secondary battery, a first electrode tab group (210A) includes a plurality of first electrode tabs (210B) having different first lengths from a base portion of the first electrode tab group (210A) to a first bonding portion (310A), and a second electrode tab group (220A) includes a plurality of second electrode tabs (220B) having different second lengths from a base portion of the second electrode tab group (220A) to a second bonding portion (320A). The maximum value L1 of the first length in the first electrode sheet group (210A) and the maximum value L2 of the second length in the second electrode sheet group (210A) satisfy the relationship L2 / L1 > 1.2.

Description

Technical Field

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

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

[0003] From the viewpoint of stably and efficiently manufacturing a highly reliable secondary battery and from the viewpoint of improving energy density, the battery described in Japanese Patent No. 4537353 still has room for further improvement. Summary of the invention

[0004] The present technology aims to provide a secondary battery and a method for manufacturing the secondary battery, which can stably and efficiently manufacture a secondary battery with high energy density and high reliability.

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

[0006] [1] A secondary battery, comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode, the electrode body having a first electrode sheet group electrically connected to the first electrode at a first end thereof, and a second electrode sheet group electrically connected to the second electrode at a second end located on the opposite side to the first end; a case that accommodates the electrode body; and a first electrode terminal and a second electrode terminal that are disposed in the case, the case comprising: a case body having a first opening and a second opening that is opposite to the first opening; a first sealing plate that seals the first opening and is provided with the first electrode terminal; and a second sealing plate that seals the second opening and is provided with the second electrode terminal, the first electrode terminal and the first electrode terminal being connected to each other. The electrode sheet group is electrically connected, the second electrode terminal is electrically connected to the second electrode sheet group, the first electrode sheet group has a first joint portion, the first joint portion is joined to the first other component in a manner of forming a conductive path for conducting electricity to the first electrode terminal, the second electrode sheet group has a second joint portion, the second joint portion is joined to the second other component in a manner of forming a conductive path for conducting electricity to the second electrode terminal, the first electrode sheet group includes a plurality of first electrode sheets with first lengths different from each other from the root of the first electrode sheet group to the first joint portion, the second electrode sheet group includes a plurality of second electrode sheets with second lengths different from each other from the root of the second electrode sheet group to the second joint portion, and the maximum value L1 of the first length in the first electrode sheet group and the maximum value L2 of the second length in the second electrode sheet group satisfy the relationship of L2 / L1>1.2.

[0007] [2] In the secondary battery described in [1], the first other component is housed in the shell and included in the first current collector that electrically connects the first electrode to the first electrode terminal, the second other component is housed in the shell and included in the second current collector that electrically connects the second electrode to the second electrode terminal, the first electrode sheet group has a first bent portion, the front end side of the first bent portion in the first electrode sheet group is joined to the first current collector to form a first joint portion, and the second electrode sheet group has a second bent portion, the front end side of the second bent portion in the second electrode sheet group is joined to the second current collector to form a second joint portion.

[0008] [3] In the secondary battery described in [2], a region of the first current collector where the first joining portion is located is arranged along the first sealing plate, and a region of the second current collector where the second joining portion is located is arranged along the second sealing plate.

[0009] [4] In the secondary battery described in any one of [1] to [3], an electrolyte is contained in the shell, a through hole is formed in the second sealing plate, the through hole is sealed by a sealing component, the first electrode has a first active material layer, the second electrode has a second active material layer, and in the direction connecting the first sealing plate and the second sealing plate, a first distance D1 from an end of the first active material layer on the side close to the first sealing plate to the first sealing plate and a second distance D2 from an end of the second active material layer on the side close to the second sealing plate to the second sealing plate satisfy the relationship D2>D1.

[0010] [5] The secondary battery according to any one of [1] to [4], further comprising: a first separator disposed between the first sealing plate and the electrode body; and a second separator disposed between the second sealing plate and the electrode body.

[0011] [6] In the secondary battery according to any one of [1] to [5], the minimum value L1' of the first length in the first electrode sheet group and the minimum value L2' of the second length in the second electrode sheet group satisfy the relationship of L2' / L1'>1.5.

[0012] [7] In the secondary battery according to any one of [1] to [6], the thickness of the plurality of second electrode sheets is greater than the thickness of the plurality of first electrode sheets.

[0013] [8] A method for manufacturing a secondary battery, comprising the following steps: a step of preparing a shell body, wherein the shell body has a first opening and a second opening opposite to the first opening; a step of forming an electrode body, wherein the electrode body includes a first electrode and a second electrode having a polarity different from that of the first electrode, the electrode body having a first electrode sheet group electrically connected to the first electrode at a first end thereof, and a second electrode sheet group electrically connected to the second electrode at a second end located on the opposite side to the first end; a step of inserting the electrode body into the shell body from the side where the second end is located through the first opening after the electrode body is formed; a step of electrically connecting a first electrode terminal provided on a first sealing plate to the first electrode sheet group; a step of electrically connecting a second electrode terminal provided on a second sealing plate to the second electrode sheet group after the first electrode terminal is electrically connected to the first electrode sheet group; a step of electrically connecting the first electrode terminal to the first electrode sheet group A process of sealing the first opening with a first sealing plate after connection; and a process of sealing the second opening with a second sealing plate after electrically connecting the second electrode terminal to the second electrode sheet group, wherein the first electrode sheet group has a first joint portion, which is joined to the first other component in a manner of forming a conductive path for conducting electricity to the first electrode terminal, and the second electrode sheet group has a second joint portion, which is joined to the second other component in a manner of forming a conductive path for conducting electricity to the second electrode terminal, the first electrode sheet group includes a plurality of first electrode sheets with first lengths different from each other from the root of the first electrode sheet group to the first joint portion, and the second electrode sheet group includes a plurality of second electrode sheets with second lengths different from each other from the root of the second electrode sheet group to the second joint portion, and the maximum value L1 of the first length in the first electrode sheet group and the maximum value L2 of the second length in the second electrode sheet group satisfy the relationship of L2 / L1>1.2.

[0014] [9] In the method for manufacturing a secondary battery according to [8], the first electrode terminal is electrically connected to the first electrode sheet group before the electrode body is inserted into the case body.

[0015]

[10] In the method for manufacturing a secondary battery described in [8] or [9], the first other component is housed in the shell body and included in the first current collector that electrically connects the first electrode to the first electrode terminal, and the second other component is housed in the shell body and included in the second current collector that electrically connects the second electrode to the second electrode terminal.

[0016]

[11] In the method for manufacturing a secondary battery according to any one of [8] to

[10] , before the electrode body is inserted into the case body, the first other component is joined to the first electrode sheet group, and the second other component is joined to the second electrode sheet group.

[0017]

[12] The method for manufacturing a secondary battery according to any one of [8] to

[11] , further comprising the step of covering the electrode body before being inserted into the case body with an insulating electrode body holder.

[0018]

[13] In the method for manufacturing a secondary battery described in any one of [8] to

[12] , the method further comprises the following steps, namely: a step of injecting electrolyte into the shell body through the injection hole formed in the second sealing plate; and a step of sealing the injection hole using a sealing member, injecting electrolyte into the shell body in a state where the shell body is inclined in a manner such that the direction connecting the first sealing plate and the second sealing plate intersects with the horizontal direction and the second sealing plate is located above the first sealing plate in the vertical direction.

[0019]

[14] In the method for manufacturing a secondary battery according to

[13] , the electrolyte is injected into the case body with the separator disposed between the first sealing plate and the electrode body.

[0020] 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

[0021] Figure 1 It is a front view of a secondary battery.

[0022] Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0023] Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery.

[0024] Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0025] Figure 5 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0026] Figure 6 It is a front view showing a negative electrode original plate before forming a negative electrode plate.

[0027] Figure 7 yes Figure 6 VII-VII cross-sectional view of the negative electrode original plate shown.

[0028] Figure 8 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0029] Fig. 9 It is a front view showing a positive electrode original plate before forming a positive electrode plate.

[0030] Fig.10 yes Fig. 9 XX cross-sectional view of the positive electrode original plate shown.

[0031] Fig.11 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0032] Fig.12 It is a diagram showing an electrode body and a current collector taken out from a secondary battery.

[0033] Fig.13 It is a diagram showing the connection structure between the negative electrode sheet group and the negative electrode current collector.

[0034] Fig.14 yes Fig.13 Front view of the connection structure shown.

[0035] Fig.15 yes Fig.13 A cross-sectional view of the connection structure shown.

[0036] Fig.16 It is a diagram showing the step of inserting the electrode body into the case body.

[0037] Fig.17 This is a diagram showing a step of placing a separator between a sealing plate and an electrode body.

[0038] Fig.18 It is a cross-sectional view showing a state where a separator is arranged between a sealing plate and an electrode body.

[0039] Fig.19 It is a diagram showing the connection structure between the positive electrode sheet group and the positive electrode current collector.

[0040] Fig. 20 yes Fig.19 A cross-sectional view of the connection structure shown.

[0041] Fig.21 It is a cross-sectional view showing a modified example of a separator disposed between a sealing plate and an electrode body.

[0042] Fig. 22 Yes means Fig.21 A diagram of the separator on the negative electrode side is shown.

[0043] Fig.23 Yes means Fig.21 A diagram of the separator on the positive electrode side is shown.

[0044] Fig.24 This is a diagram for explaining the difference in length of a plurality of negative electrode sheets included in a negative electrode sheet group.

[0045] Fig.25 It is a diagram for explaining the length of the negative electrode sheet from the root portion to the joining portion of the negative electrode sheet group.

[0046] Fig.26 This is a diagram for explaining the difference in length of a plurality of positive electrode sheets included in a positive electrode sheet group.

[0047] Fig. 27 This is a diagram for explaining the length of the positive electrode sheet from the root of the positive electrode sheet group to the joining portion.

[0048] Fig.28 This is a diagram for explaining the distance from the end of the electrode active material layer on the sealing plate side to the sealing plate.

[0049] Fig.29 It is a flowchart showing each process of the manufacturing method of a secondary battery. DETAILED DESCRIPTION

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.).

[0054] 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.

[0055] (Overall structure of the battery)

[0056] 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.

[0057] 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.

[0058] 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 sealing plate 121 (first sealing plate), and a sealing plate 122 (second sealing plate).

[0059] 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, and similarly, the Y-axis direction (second direction) is called the “thickness direction” of the secondary battery 1 or the shell body 110, and similarly, the Z-axis direction (third direction) is called the “height direction” of the secondary battery 1 or the shell body 110.

[0060] 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.

[0061] 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.

[0062] like Figure 1 , Figure 2 As shown in FIG. 1 , sealing plates 121 and 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.

[0063] In the present embodiment, the shell body 110 is formed in the width direction (X-axis direction) of the secondary battery 1 to be longer than the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X-axis 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-axis 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.

[0064] like Figure 3 As shown, an opening 111 (first opening) is provided at one end of the housing body 110. The opening 111 is sealed by a sealing plate 121. The sealing plate 121 is provided with a negative terminal 131 (first electrode terminal), a liquid injection hole 141, and an exhaust valve 151. The positions of the negative terminal 131, the liquid injection hole 141, and the exhaust valve 151 can be appropriately changed. The opening 111 and the sealing plate 121 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction.

[0065] like Figure 4 As shown, an opening 112 (second opening) is provided at the other end of the housing body 110. The opening 112 is sealed by a sealing plate 122. The sealing plate 122 is provided with a positive terminal 132 (second electrode terminal), a liquid injection hole 142, and an exhaust valve 152. The positions of the positive terminal 132, the liquid injection hole 142, and the exhaust valve 152 can be appropriately changed. The opening 112 and the sealing plate 122 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction.

[0066] The sealing plates 121 and 122 are made of metal. Specifically, the sealing plates 121 and 122 are made of aluminum, aluminum alloy, iron, iron alloy, or the like.

[0067] 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 .

[0068] 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 .

[0069] 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.

[0070] The liquid injection holes 141 and 142 are sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The electrode body 200 includes a negative electrode sheet group 210A (first electrode sheet group) provided at the end (first end) on the sealing plate 121 side, and a positive electrode sheet group 220A (second electrode sheet group) provided at the end (second end) on the sealing plate 122 side. 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 portion (the portion where the positive electrode plate and the negative electrode plate are stacked via the separator) of the electrode body 200 toward the sealing plates 121 and 122, respectively.

[0076] 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 .

[0077] The negative electrode current collector 310 is disposed on the 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, a metal), for example, copper or a copper alloy.

[0078] The positive electrode collector 320 is arranged on the sealing plate 122 via an insulating member 420 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 sealing plate 122 directly or via the positive electrode collector 320. In this case, the sealing plate 122 can also serve as the positive terminal 132.

[0079] (Structure of Electrode Body 200)

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 .

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] like Fig.11 As 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 .

[0094] 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 does not necessarily need to be provided at the root of the positive electrode sheet 220B.

[0095] 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.

[0096] (Connection Structure of Electrode Body 200 and Current Collector 300)

[0097] 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.

[0098] The negative electrode sheet group 210A is joined to the negative electrode collector 310 at the joint 310A, and the positive electrode sheet group 220A is joined to the positive electrode collector 320 at the joint 320A. The joints 310A and 320A can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, riveting, etc. The joints 310A and 320A constitute a conductive path between the negative electrode sheet group 210A and the positive electrode sheet group 220A and the negative terminal 131 and the positive terminal 132.

[0099] (Connection Structure between Electrode Body 200 and Negative Electrode Current Collector 310)

[0100] 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.

[0101] like Figure 13 to Figure 15 As shown, the negative electrode current collector 310 is connected to the negative electrode terminal 131 between the electrode body 200 and the 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.

[0102] 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.

[0103] The first conductive member 311 and the second conductive member 312 are attached to the inner surface side of the sealing plate 121 via an insulating member 410 made of resin.

[0104] The negative terminal 131 is mounted on the 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 sealing plate 121 and reach the second conductive member 312 of the negative electrode collector 310 provided on the inner surface side of the 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.

[0105] As the assembly order of each component, first, the negative terminal 131 and the second conductive component 312 are mounted on the 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.

[0106] The negative electrode terminal 131 may also be electrically connected to the sealing plate 121. In addition, the sealing plate 121 may also play the role of the negative electrode terminal 131.

[0107] 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.

[0108] (Step of Inserting Electrode Body 200)

[0109] Fig.16 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.16As shown, an insulating sheet 600 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0110] 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).

[0111] 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.

[0112] Fig.17 This is a diagram showing a step of placing the separator 510 between the 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 sealing plate 121 and the electrode body 200 .

[0113] like Fig.17 , Fig.18 As shown, the negative electrode sheet group 210A from the electrode body 200 toward the sealing plate 121 is bent from the center of the sealing plate 121 in the Y-axis direction toward the end, and then folded back toward the center. The separator 510 is arranged to accommodate the bent negative electrode sheet group 210A (bent portion).

[0114] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 are joined to each other by sliding along the Y-axis direction from the end side toward the center side of the sealing plate 121. Thus, the spacer 510 is fixed to the sealing plate 121 via the insulating member 410, so that the stability of the position of the spacer 510 is increased.

[0115] 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.

[0116] 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 .

[0117] Refer again Fig.16 In the method for manufacturing the secondary battery 1 of this embodiment, the electrode body 200 is inserted into the case body 110 while the electrode body 200 is covered by the insulating sheet 600. This can prevent the electrode body 200 from being damaged when inserted into the case body 110.

[0118] When the electrode body 200 is inserted, 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 opening 111 into which the electrode body 200 is inserted is located above the upper end of the opening 112 in the vertical direction, so that the electrode body 200 can be inserted into the case body 110.

[0119] The electrode body 200 may be inserted by pressing the electrode body 200 from the opening 111 side or by pulling the electrode body 200 from the opening 112 side.

[0120] (Connection Structure between Electrode Body 200 and Positive Electrode Current Collector 320)

[0121] Fig.19 It is a diagram showing the connection structure between the positive electrode sheet group 220A and the positive electrode current collector 320 . Fig. 20 yes Fig.19 A cross-sectional view of the connection structure shown.

[0122] like Fig.19 and Fig. 20 As shown, the positive electrode collector 320 is provided on the inner surface side of the sealing plate 122, and is connected to the electrode body 200 and the positive electrode terminal 132. The positive electrode collector 320 includes a first conductive component 321 (first component) and a second conductive component 322 (second component). The first conductive component 321 and the second conductive component 322 are joined at a joint 323. The first conductive component 321 and the second conductive component 322 are mounted on the inner surface side of the sealing plate 122 via a resin insulating component 420.

[0123] The first conductive member 321 has a step portion 321A. The step portion 321A extends along the long side direction (Z-axis direction) of the rectangular sealing plate 122. Fig. 20 As shown, at one side relative to the step portion 321A ( Fig. 20In the region (the first region) on the left side of the step portion 321A, the first conductive component 321 is provided along the sealing plate 122 and is bonded to the positive electrode sheet group 220A (bonding portion 320A). Fig. 20 In the region (the second region) on the right side of the electrode, the first conductive component 321 is provided so as to overlap with the second conductive component 322. These structures are also the same on the negative electrode side (see Figure 13 to Figure 15 ).

[0124] exist Fig.19 and Fig. 20 , the shape of the positive electrode sheet group 220A before being bent is shown, but in the completed secondary battery 1, the positive electrode sheet group 220A is stored in the case body 110 in a bent state. It is preferred that the positive electrode sheet group 220A is bent (reformed) to a state close to the final shape before the electrode body 200 is stored in the case body 110.

[0125] The positive electrode sheet group 220A is joined to the first conductive member 321 of the positive electrode current collector 320 at the joint 320A. The first conductive member 321 is connected to the second conductive member 322 at the joint 323. The joint 323 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, riveting, or the like.

[0126] The positive terminal 132 is mounted on the sealing plate 122 via an insulating component 420A made of resin. The positive terminal 132 is configured to be exposed on the outside of the sealing plate 122 and reach the second conductive component 322 of the positive electrode collector 320 provided on the inner surface side of the sealing plate 122. The positive terminal 132 and the second conductive component 322 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 component 322, the positive terminal 132 is inserted into the through hole, and after the positive terminal 132 is riveted on the second conductive component 322, the riveted portion and the second conductive component 322 are welded at the joint 132A, thereby connecting the positive terminal 132 to the second conductive component 322.

[0127] As the assembly order of each component, first, the positive terminal 132 and the second conductive component 322 are mounted on the sealing plate 122 together with the insulating components 420 and 420A. Next, the first conductive component 321 connected to the electrode body 200 is mounted on the second conductive component 322. At this time, the first conductive component 321 is arranged on the insulating component 420 in a manner that a part of the first conductive component 321 overlaps with the second conductive component 322. Next, the first conductive component 321 and the second conductive component 322 are welded and connected at the joint 323. In addition, the insulating components 420 and 420A may also be composed of one component.

[0128] The positive electrode terminal 132 may also be electrically connected to the sealing plate 122. In addition, the sealing plate 122 may also play the role of the positive electrode terminal 132.

[0129] In addition, Fig.19 and Fig. 20 In FIG. 1 , the positive electrode current collector 320 is exemplified as being composed of two members (the first conductive member 321 and the second conductive member 322 ), but the positive electrode current collector 320 may be composed of a single member.

[0130] (Modification of Spacer)

[0131] Fig.21 The diagram shows a modified example of the separator disposed between the sealing plates 121 and 122 and the electrode body 200 . Fig. 22 , Fig.23 They are respectively Fig.21 The diagram shows a separator 510 on the negative electrode side and a separator 520 on the positive electrode side.

[0132] Figure 21 to Figure 23 The separators 510 and 520 shown in the example respectively have: through holes 510A and 520A, which are connected to the injection holes 141 and 142 respectively; through holes 510B and 520B, which are connected to the exhaust valves 151 and 152; recesses 510C and 520C, which are used to avoid interference with the negative electrode collector 310 and the positive electrode collector 320; and recesses 510D and 520D, which are used to avoid interference with the negative electrode sheet group 210A and the positive electrode sheet group 220A. In addition, the separators 510 and 520 do not necessarily have to be of the same type of structure. For example, the through hole or the recess may be provided only on one side, or they may be composed of different materials.

[0133] By forming the through holes 510A, 510B, 520A, 520B and the recesses 510C, 510D, 520C, 520D in the separators 510 and 520, the separators 510 and 520 can be arranged in a manner that avoids interference with the electrode body 200 and the current collector 300 inside the case body 110 and does not hinder the functions of the injection holes 141 and 142 and the exhaust valves 151 and 152. For example, the separators 510 and 520 can also be fixed (fitted, bonded, welded, etc.) to the sealing plates 121 and 122.

[0134] The structures of the through holes 510A, 510B, 520A, 520B and the recesses 510C, 510D, 520C, 520D are not limited to Figure 21 to Figure 23 For example, a cutout portion or a slit portion may be provided instead of the through hole.

[0135] (Structure of electrode sheet)

[0136] Next, refer to Figure 24 to Figure 27 The structures of the negative electrode sheet 210B and the positive electrode sheet 220B will be described.

[0137] like Fig.24 As shown, the plurality of negative electrode sheets 210B included in the negative electrode sheet group 210A are bent respectively, and the collected negative electrode sheets 210B reach the joint 310A. Therefore, the lengths of the plurality of negative electrode sheets 210B are different from each other. Fig.24 , the longest negative electrode sheet 210B1 and the shortest negative electrode sheet 210B2 in the negative electrode sheet group 210A are schematically shown. Fig.25 , the length L1 (the maximum value of the first length) of the negative electrode sheet 210B1 (the longest negative electrode sheet 210B) from the base of the negative electrode sheet group 210A to the junction 310A is shown.

[0138] like Fig.26 As shown, the plurality of positive electrode sheets 220B included in the positive electrode sheet group 220A are bent respectively, and the collected positive electrode sheets 220B reach the joint 320A. Therefore, the lengths of the plurality of positive electrode sheets 220B are different from each other. Fig.26 , the longest positive electrode sheet 220B1 and the shortest positive electrode sheet 220B2 in the positive electrode sheet group 220A are schematically shown. Fig. 27 , the length L2 (the maximum value of the second length) of the positive electrode sheet 220B1 (the longest positive electrode sheet 220B) from the base of the positive electrode sheet group 220A to the junction portion 320A is shown.

[0139] also, Fig.25 and Fig. 27 The lengths L1 and L2 shown are measured in a state where the negative electrode plate 210 and the positive electrode plate 220 are extended in one plane and the negative electrode sheet 210B1 and the positive electrode sheet 220B1 are not bent. Fig.25 and Fig. 27 The lengths L1 and L2 shown are the lengths along the negative electrode sheet 210B1 and the positive electrode sheet 220B1 , which are different from the straight-line distances when the negative electrode sheet 210B1 and the positive electrode sheet 220B1 are bent.

[0140] In the present embodiment, the length L1 of the negative electrode sheet 210B1 from the root of the negative electrode sheet group 210A to the joint 310A (see Fig.25 ), and the length L2 of the positive electrode sheet 220B1 from the root of the positive electrode sheet group 220A to the joint 320A (see Fig. 27) satisfies the relationship of L2 / L1>1.2 (more preferably L2 / L1>1.5). That is, the longest negative electrode sheet 210B1 among the plurality of negative electrode sheets 210B is formed shorter than the longest positive electrode sheet 220B1 among the plurality of positive electrode sheets 220B.

[0141] The length L1′ of the negative electrode sheet 210B2 from the root of the negative electrode sheet group 210A to the joint 310A (reduced to Fig.25 The negative electrode sheet 210B1 is replaced by the negative electrode sheet 210B2 for reference), and the length L2′ of the positive electrode sheet 220B2 from the root of the positive electrode sheet group 220A to the junction 320A (the length L2′ of the positive electrode sheet 220B2 from the root of the positive electrode sheet group 220A to the junction 320A) Fig. 27 The positive electrode sheet 220B1 is replaced by the positive electrode sheet 220B2 for reference) satisfies the relationship of L2' / L1'>1.5 (more preferably L2' / L1'>1.8). That is, the shortest negative electrode sheet 210B2 among the plurality of negative electrode sheets 210B is formed shorter than the shortest positive electrode sheet 220B2 among the plurality of positive electrode sheets 220B.

[0142] Thus, in the secondary battery 1, the negative electrode sheet 210B is formed relatively short, and the positive electrode sheet 220B is formed relatively long. The average value L10 of the length from the root of the negative electrode sheet group 210A to the joint 310A related to the plurality of negative electrode sheets 210B is smaller than the average value L20 of the length from the root of the positive electrode sheet group 220A to the joint 320A related to the plurality of positive electrode sheets 220B.

[0143] (Distance from active material layer to sealing plate)

[0144] Fig.28 1 is a diagram for explaining the distance from the end of the electrode active material layer on the sealing plate side to the sealing plates 121 and 122. Fig.28 , the distance D2 from the end of the positive electrode active material layer 222 on the sealing plate 122 side to the sealing plate 122 is greater than the distance D1 from the end of the negative electrode active material layer 212 on the sealing plate 121 side to the sealing plate 121. That is, on the positive electrode side (sealing plate 122 side), a larger space than on the negative electrode side (sealing plate 121 side) is formed between the active material layer and the sealing plate.

[0145] In this case, it is preferred that the electrolyte is injected into the outer casing 100 from the injection hole 142 on the positive electrode side. By injecting from the positive electrode side where a relatively large gap is formed, the space for temporarily storing the electrolyte can be enlarged, so that the injection process can be performed efficiently. In addition, the situation where the electrolyte is ejected from the injection hole 142 can be effectively suppressed. In addition, even if a part of the sealing component that seals the injection hole 142 protrudes toward the inner side of the sealing plate 122, it is more effective to suppress the protruding sealing component from contacting the electrode body 200. As the sealing component, a component that includes a resin sealing portion or a rubber portion in a portion can also be used.

[0146] (Manufacturing process of secondary battery 1)

[0147] Fig.29 1 is a flow chart showing each step of the method for manufacturing the secondary battery 1. Fig.29 As shown, in S10, the case body 110 is prepared. Next, in S20, the electrode body 200 is manufactured. In S30, the electrode terminals on the sealing plates 121 and 122 are electrically connected to the electrode sheet group of the electrode body 200. Fig.29 In the example, first, the negative electrode terminal 131 is electrically connected to the negative electrode sheet group 210A (S31), and then the positive electrode terminal 132 is electrically connected to the positive electrode sheet group 220A (S32).

[0148] More specifically, after the negative terminal 131 is electrically connected to the negative electrode sheet group 210A (S31), first, the first conductive component 321 of the positive electrode collector 320 is joined to the positive electrode sheet group 220A (S32A), and then, the separator 510 is arranged between the sealing plate 121 on the negative electrode side and the electrode body 200 (S41). Thereafter, the electrode body 200 is inserted into the shell body 110 (S50). 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 by joining the first conductive component 321 to the second conductive component 322 (S32B), and the separator 520 is arranged between the sealing plate 122 on the positive electrode side and the electrode body 200 (S42).

[0149] After the connection between the electrode terminal and the electrode sheet group (S30), the installation of the separators 510 and 520 (S40), and the insertion of the electrode body 200 (S50) are all completed in the above order, the openings 111 and 112 are sealed respectively by the sealing plates 121 and 122 (S60). The sealing process based on the sealing plates 121 and 122 is performed by laser welding, for example.

[0150] In the present technology, the order of connecting the electrode terminal and the electrode sheet group (S30), setting the separators 510 and 520 (S40), and inserting the electrode body 200 (S50) is not limited to Fig.29 For example, the negative terminal 131 and the negative electrode sheet group 210A may be electrically connected (S31) and the separator 510 may be provided (S41) after the electrode body 200 is inserted (S50) or in the middle of the electrode body 200 being inserted (S50).

[0151] exist Fig.29 In the example, after the step (S61) of sealing the opening 111 with the sealing plate 121 on the negative electrode side is performed, the step (S62) of sealing the opening 112 with the sealing plate 122 on the positive electrode side is performed, but the step (S61) of sealing the opening 111 with the sealing plate 121 may be performed after the step (S62) of sealing the opening 112 with the sealing plate 122. Furthermore, at least a part of the steps (S61, S62) of sealing with the sealing plates 121 and 122 may be performed simultaneously.

[0152] (summary)

[0153] The secondary battery 1 and the manufacturing method thereof according to the present embodiment will be generally described as follows. However, the scope of the present technology is not necessarily limited to the examples in the present embodiment.

[0154] The secondary battery 1 of this embodiment comprises: an electrode body 200, which includes a negative electrode plate 210 (first electrode) and a positive electrode plate 220 (second electrode), and the electrode body 200 has a negative electrode sheet group 210A (first electrode sheet group) at one end thereof and a positive electrode sheet group 220A (second electrode sheet group) at the other end thereof; an outer casing 100 (shell), which accommodates the electrode body 200; and a negative terminal 131 (first electrode terminal) and a positive terminal 132 (second electrode terminal), which are arranged on the outer casing 100.

[0155] The outer casing 100 includes: a case body 110 having an opening 111 (first opening) and an opening 112 (second opening) opposite to the opening 111; a sealing plate 121 (first sealing plate) that seals the opening 111 and is provided with a negative terminal 131; and a sealing plate 122 (second sealing plate) that seals the opening 112 and is provided with a positive terminal 132. The negative terminal 131 is electrically connected to the negative electrode sheet group 210A, and the positive terminal 132 is electrically connected to the positive electrode sheet group 220A. The negative electrode sheet group 210A has a joint portion 310A (first joint portion), which is joined to the first conductive component 311 (first other component) of the negative electrode collector 310 (first collector) in a manner that forms a conductive path for conducting electricity to the negative electrode terminal 131, and the positive electrode sheet group 220A has a joint portion 320A (second joint portion), which is joined to the first conductive component 321 (second other component) of the positive electrode collector 320 (second collector) in a manner that forms a conductive path for conducting electricity to the positive electrode terminal 132. In addition, the electrode sheet group may also be joined to a sealing plate or an electrode terminal.

[0156] like Fig.29As shown, the manufacturing method of the secondary battery 1 of the present embodiment comprises: a step (S10) of preparing a shell body 110, wherein the shell body 110 has an opening 111 and an opening 112 opposite to the opening 111; a step (S20) of making an electrode body 200, wherein the electrode body 200 includes a negative electrode plate 210 and a positive electrode plate 220, and the electrode body 200 has a negative electrode sheet group 210A (a first electrode sheet group) including a negative electrode sheet 210B electrically connected to the negative electrode plate 210 at one end thereof, and has a positive electrode sheet group 220A (a second electrode sheet group) including a positive electrode sheet 220B electrically connected to the positive electrode plate 220 at the other end thereof; a step (S31) of electrically connecting the negative terminal 131 provided on the sealing plate 121 to the negative electrode sheet group 210A; and a step (S32) of electrically connecting the positive electrode A process (S32A) of joining the first conductive component 321 of the collector 320 to the positive electrode sheet group 220A; a process (S41) of configuring the separator 510 between the sealing plate 121 on the negative electrode side and the electrode body 200; a process (S50) of inserting the electrode body 200 into the shell body 110; after the electrode body 200 is inserted into the shell body 110, joining the first conductive component 321 and the second conductive component 322 to electrically connect the positive terminal 132 to the positive electrode sheet group 220A (S32B); a process (S42) of configuring the separator 520 between the sealing plate 122 on the positive electrode side and the electrode body 200; a process (S61) of sealing the opening 111 using the sealing plate 121; and a process (S62) of sealing the opening 112 using the sealing plate 122. In addition, the negative electrode sheet group 210A may include a plurality of negative electrode sheets 210B1 having the same length (first length) from the root of the negative electrode sheet group 210A to the junction 310A. The positive electrode sheet group 220A may include a plurality of positive electrode sheets 220B1 having the same length (second length) from the root of the positive electrode sheet group 220A to the junction 320A.

[0157] The step (S31) of electrically connecting the negative electrode terminal 131 to the negative electrode sheet group 210A includes joining the negative electrode sheet group 210A to the first conductive member 311 of the negative electrode collector 310 at the joint 310A. The step (S32) of electrically connecting the positive electrode terminal 132 to the positive electrode sheet group 220A includes joining the positive electrode sheet group 220A to the first conductive member 321 of the positive electrode collector 320 at the joint 320A.

[0158] In the secondary battery 1, the negative electrode sheet group 210A includes a plurality of negative electrode sheets 210B (first electrode sheets) having different lengths (first lengths) from the root of the negative electrode sheet group 210A to the junction 310A, and the positive electrode sheet group 220A includes a plurality of positive electrode sheets 220B (second electrode sheets) having different lengths (second lengths) from the root of the positive electrode sheet group 220A to the junction 320A. For the longest electrode sheet, the length L1 of the negative electrode sheet 210B1 from the root of the negative electrode sheet group 210A to the junction 310A and the length L2 of the positive electrode sheet 220B1 from the root of the positive electrode sheet group 220A to the junction 320A satisfy the relationship of L2 / L1>1.2 (more preferably L2 / L1>1.5).

[0159] In addition, for the shortest electrode sheet, the length L1' of the negative electrode sheet 210B2 from the root of the negative electrode sheet group 210A to the joint 310A and the length L2' of the positive electrode sheet 220B2 from the root of the positive electrode sheet group 220A to the joint 320A satisfy the relationship L2' / L1'>1.5 (preferably L2' / L1'>1.8).

[0160] For the negative electrode sheet group 210A and the positive electrode sheet group 220A, the front end side of their bent portions is joined to the negative electrode collector 310 and the positive electrode collector 320 to form the joints 310A and 320A, respectively. The region where the joint 310A in the negative electrode collector 310 is located is arranged along the sealing plate 121, and the region where the joint 320A in the positive electrode collector 320 is located is arranged along the sealing plate 122. However, the negative electrode collector 310 and the positive electrode collector 320 do not necessarily extend parallel to the sealing plates 121 and 122, and for example, an inclination of about ±30° is allowed.

[0161] In the direction connecting the sealing plate 121 and the sealing plate 122 (X-axis direction), the distance D1 (first distance) from the end of the negative electrode active material layer 212 (first active material layer) on the sealing plate 121 side to the sealing plate 121, and the distance D2 (second distance) from the end of the positive electrode active material layer 222 (second active material layer) on the sealing plate 122 side to the sealing plate 122 satisfy the relationship D2>D1 (more preferably D2 / D1>1.2, and further preferably D2 / D1>1.5).

[0162] A separator 510 (first separator) and a separator 520 (second separator) are respectively arranged between the sealing plate 121 and the electrode body 200 and between the sealing plate 122 and the electrode body 200. The separators 510 and 520 are preferably formed to abut against the region of the electrode body 200 where the negative electrode sheet group 210A and the positive electrode sheet group 220A are not formed.

[0163] For example, the thickness of the negative electrode sheet 210B (one sheet) is 5 μm or more and 20 μm or less, and the thickness of the positive electrode sheet 220B (one sheet) is 5 μm or more (preferably 8 μm or more) and 20 μm or less. Here, it is preferred that the thickness (second thickness) of each of the plurality of positive electrode sheets 220B is greater than the thickness (first thickness) of each of the plurality of negative electrode sheets 210B. As an example, it is preferred that the thickness of the positive electrode sheet 220B (one sheet) is 1.2 times or more (more preferably 1.5 times or more) the thickness of the negative electrode sheet 210B (one sheet).

[0164] The number of negative electrode sheets 210B constituting the negative electrode sheet group 210A (the first number of sheets S1) and the number of positive electrode sheets 220B constituting the positive electrode sheet group 220A (the second number of sheets S2) may be the same or different. As one example, it is preferably 0.5<S1 / S2<1.5 (more preferably 0.8<S1 / S2<1.2).

[0165] In the present embodiment, the step (S31) of electrically connecting the negative terminal 131 to the negative electrode sheet group 210A is performed before the step (S50) of inserting the electrode body 200 into the case body 110, but the scope of the present technology is not limited thereto. The step (S31) of electrically connecting the negative terminal 131 to the negative electrode sheet group 210A can be performed in the middle of the step (S50) of inserting the electrode body 200 into the case body 110, or can be performed after the step (S50) of inserting the electrode body 200 into the case body 110.

[0166] In addition, in the present embodiment, the first conductive component 311 of the negative electrode collector 310 is joined to the negative electrode sheet group 210A, and the first conductive component 321 of the positive electrode collector 320 is joined to the positive electrode sheet group 220A before the step (S50) of inserting the electrode body 200 into the case body 110, but the scope of the present technology is not limited to this.

[0167] The electrode body 200 before being inserted into the case body 110 may be covered by the insulating sheet 600. However, in the present technology, the insulating sheet 600 covering the electrode body 200 is not necessarily required.

[0168] When the electrolyte is injected into the case body 110 through the injection hole 142 formed in the sealing plate 122 on the positive electrode side, the electrolyte is preferably injected in a state where the case body 110 is tilted so that the direction connecting the sealing plates 121 and 122 (X-axis direction) intersects with the horizontal direction and the sealing plate 122 on the positive electrode side is located vertically above the sealing plate 121 on the negative electrode side. At this time, the electrolyte is preferably injected in a state where the separator 510 is arranged between the sealing plate 121 on the negative electrode side and the electrode body 200.

[0169] However, it is not necessary to tilt the housing body 110 when injecting liquid in the present technology. In addition, the tilt angle when the housing body 110 is tilted for injection can also be appropriately changed. As one example, it is preferred that the direction connecting the sealing plates 121 and 122 (X-axis direction) is tilted by 30° or more relative to the horizontal direction, more preferably by 45° or more or 60° or more, and most preferably, the direction connecting the sealing plates 121 and 122 (X-axis direction) is approximately vertical (tilted at an angle close to 90° relative to the horizontal direction).

[0170] (Function and Effect)

[0171] According to the secondary battery 1 of this embodiment, by inserting the electrode body 200 into the shell body 110 having the openings 111 and 112 facing each other and respectively providing the negative terminal 131 and the positive terminal 132 on the sealing plates 121 and 122 for sealing the openings 111 and 112, the height of the secondary battery 1 can be reduced and the mountability of the secondary battery 1 on the vehicle can be improved.

[0172] In addition, the maximum value L1 of the length from the root of the negative electrode sheet group 210A to the joint 310A and the maximum value L2 of the length from the root of the positive electrode sheet group 220A to the joint 320A satisfy a predetermined relationship (L2 / L1>1.2). That is, the negative electrode sheet 210B is formed relatively short, and the positive electrode sheet 220B is formed relatively long.

[0173] By forming the negative electrode sheet 210B relatively short, the volume occupied by the electrode assembly 200 in the space inside the case body 110 can be increased, and thus the energy density of the secondary battery 1 can be increased.

[0174] Furthermore, since the positive electrode sheet 220B is formed relatively long, when the electrode assembly 200 is inserted into the case body from the positive electrode sheet group 220A side, the positive electrode sheet group 220A and the first conductive member 321 of the positive electrode collector 320 can be easily joined at the opening 112 side of the case body 110 .

[0175] Furthermore, by arranging the regions where the joints 310A, 320A of the negative electrode current collector 310 and the positive electrode current collector 320 with the negative electrode sheet group 210A and the positive electrode sheet group 220A are located along the sealing plates 121 , 122 , the energy density of the secondary battery 1 can be further increased.

[0176] Furthermore, by electrically connecting the relatively short negative electrode sheet group 210A to the negative electrode terminal 131 ( S31 ) before electrically connecting the relatively long positive electrode sheet group 220A to the positive electrode terminal 132 ( S32 ), damage to the negative electrode sheet group 210A can be effectively suppressed.

[0177] In addition, when the electrolyte is injected in a state where the shell body 110 is tilted in such a way that the sealing plate 122 on the positive electrode side is located vertically above the sealing plate 121 on the negative electrode side, by arranging the separator 510 between the sealing plate 121 on the negative electrode side and the electrode body 200, the separator 510 can hold the electrode body 200, thereby effectively suppressing damage to the negative electrode sheet group 210A.

[0178] As described above, according to the secondary battery 1 and the method for manufacturing the same according to the present embodiment, a secondary battery having high energy density and high reliability can be manufactured stably and efficiently.

[0179] 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, the electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode, the electrode body having a first electrode sheet group electrically connected to the first electrode at a first end thereof, and a second electrode sheet group electrically connected to the second electrode at a second end located on the opposite side to the first end; a shell that accommodates the electrode body; and a first electrode terminal and a second electrode terminal, which are arranged on the housing, The housing comprises: a housing body having a first opening and a second opening opposite to the first opening; a first sealing plate for sealing the first opening and provided with the first electrode terminal; and a second sealing plate for sealing the second opening and provided with the second electrode terminal, The first electrode terminal is electrically connected to the first electrode sheet group. The second electrode terminal is electrically connected to the second electrode sheet group. The first electrode sheet group has a first joint portion joined to a first other member so as to form a conductive path for conducting electricity to the first electrode terminal. The second electrode sheet group has a second joint portion joined to a second other member so as to form a conductive path for conducting electricity to the second electrode terminal. The first electrode sheet group includes a plurality of first electrode sheets having first lengths from a base of the first electrode sheet group to the first joining portion that are different from each other. The second electrode sheet group includes a plurality of second electrode sheets having second lengths from a base of the second electrode sheet group to the second joining portion that are different from each other. The maximum value L1 of the first length in the first electrode sheet group and the maximum value L2 of the second length in the second electrode sheet group satisfy the relationship of L2 / L1 > 1.

2.

2. The secondary battery according to claim 1, characterized in that: The first other component is housed in the housing and is included in a first current collector that electrically connects the first electrode and the first electrode terminal. The second other component is housed in the housing and is included in a second current collector that electrically connects the second electrode and the second electrode terminal. The first electrode sheet group has a first bent portion, and the front end side of the first bent portion in the first electrode sheet group is joined to the first current collector to form the first joint portion. The second electrode sheet group includes a second bent portion, and a front end side of the second bent portion in the second electrode sheet group is joined to the second current collector to form the second joined portion.

3. The secondary battery according to claim 2, characterized in that: The region where the first joint portion is located in the first current collector is arranged along the first sealing plate. A region of the second current collector where the second joining portion is located is arranged along the second sealing plate.

4. The secondary battery according to any one of claims 1 to 3, characterized in that An electrolyte is contained in the shell. The second sealing plate has a through hole formed therein, and the through hole is sealed by a sealing member. The first electrode has a first active material layer, and the second electrode has a second active material layer. In the direction connecting the first sealing plate and the second sealing plate, a first distance D1 from the end of the first active material layer on the side close to the first sealing plate to the first sealing plate, and a second distance D2 from the end of the second active material layer on the side close to the second sealing plate to the second sealing plate satisfy the relationship D2>D1.

5. The secondary battery according to any one of claims 1 to 3, characterized in that: The device further comprises: a first separator disposed between the first sealing plate and the electrode body; and A second separator is disposed between the second sealing plate and the electrode body.

6. The secondary battery according to any one of claims 1 to 3, characterized in that: The minimum value L1' of the first length in the first electrode sheet group and the minimum value L2' of the second length in the second electrode sheet group satisfy the relationship of L2' / L1'>1.

5.

7. The secondary battery according to any one of claims 1 to 3, characterized in that The thickness of the plurality of second electrode sheets is greater than the thickness of the plurality of first electrode sheets.

8. A method for manufacturing a secondary battery, characterized in that: The following processes are available, namely: A step of preparing a housing body, wherein the housing body has a first opening and a second opening opposite to the first opening; A step of forming an electrode body, wherein the electrode body includes a first electrode and a second electrode having a polarity different from that of the first electrode, wherein the electrode body has a first electrode sheet group electrically connected to the first electrode at a first end thereof, and has a second electrode sheet group electrically connected to the second electrode at a second end located on the opposite side to the first end; After the electrode body is manufactured, a step of inserting the electrode body into the casing body from the side where the second end portion is located through the first opening; A step of electrically connecting a first electrode terminal provided on a first sealing plate to the first electrode sheet group; After the first electrode terminal is electrically connected to the first electrode sheet group, a second electrode terminal provided on the second sealing plate is electrically connected to the second electrode sheet group; After electrically connecting the first electrode terminal to the first electrode sheet group, sealing the first opening with the first sealing plate; and After the second electrode terminal is electrically connected to the second electrode sheet group, the second opening is sealed with the second sealing plate. The first electrode sheet group has a first joint portion joined to a first other member so as to form a conductive path for conducting electricity to the first electrode terminal. The second electrode sheet group has a second joint portion joined to a second other member so as to form a conductive path for conducting electricity to the second electrode terminal. The first electrode sheet group includes a plurality of first electrode sheets having first lengths from a base of the first electrode sheet group to the first joining portion that are different from each other. The second electrode sheet group includes a plurality of second electrode sheets having second lengths from a base of the second electrode sheet group to the second joining portion that are different from each other. The maximum value L1 of the first length in the first electrode sheet group and the maximum value L2 of the second length in the second electrode sheet group satisfy the relationship of L2 / L1 > 1.

2.

9. The method for manufacturing a secondary battery according to claim 8, characterized in that: Before the electrode body is inserted into the case body, the first electrode terminal is electrically connected to the first electrode sheet group.

10. The method for manufacturing a secondary battery according to claim 8 or 9, characterized in that: The first other component is housed in the case body and is included in a first current collector that electrically connects the first electrode and the first electrode terminal. The second other member is housed in the case body and is included in a second current collector that electrically connects the second electrode and the second electrode terminal.

11. The method for manufacturing a secondary battery according to claim 8 or 9, characterized in that: Before the electrode body is inserted into the case body, the first other member is joined to the first electrode sheet group, and the second other member is joined to the second electrode sheet group.

12. The method for manufacturing a secondary battery according to claim 8 or 9, characterized in that: The method further includes covering the electrode body before being inserted into the case body with an insulating electrode body holder.

13. The method for manufacturing a secondary battery according to claim 8 or 9, characterized in that: The method further comprises the following steps: a step of injecting an electrolyte into the case body through a liquid injection hole formed in the second sealing plate; and The step of sealing the injection hole by using a sealing member, The electrolyte is injected into the case body with the case body tilted so that the direction connecting the first sealing plate and the second sealing plate intersects the horizontal direction and the second sealing plate is located vertically above the first sealing plate.

14. The method for manufacturing a secondary battery according to claim 13, characterized in that: The electrolyte solution is injected into the case body with a separator disposed between the first sealing plate and the electrode body.

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