Method for manufacturing secondary battery

Abstract

To improve the energy density of a secondary battery.SOLUTION: Preparing a case body having a first opening and a second opening facing the first opening, the case body including a first electrode and a second electrode having a polarity different from a polarity of the first electrode, the case body having a first electrode tab at a first end portion, the first electrode tab being connected to the first electrode; The method includes a step of preparing an electrode body having a second electrode tab connected to a second electrode at a second end opposite to the first end, a step of electrically connecting a first electrode terminal provided on a first sealing plate and the first electrode tab, a step of inserting the electrode body into a case body from a second end side through the first opening after electrically connecting the first electrode terminal and the first electrode tab, a step of sealing the first opening with the first sealing plate after the electrode body is inserted into the case body, a step of electrically connecting a second electrode terminal provided on the second sealing plate and the second electrode tab, and a step of sealing the second opening with the second sealing plate after electrically connecting the second electrode terminal and the second electrode tab.SELECTED DRAWING: Figure 28

Description

[Technical Field]

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

[0002] Japanese Patent No. 4537353 (Patent Document 1) shows a rectangular secondary battery in which an electrode group (25) is housed in a case (14) having openings (14a, 14b) at both ends, and electrode terminals (21, 23) are attached to cap plates (33, 33') that seal the openings (14a, 14b). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4537353 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for further improvements in the energy density of secondary batteries. From the viewpoint of improving energy density, there is room for further improvement in the battery described in Patent Document 1.

[0005] An object of the present technology is to provide a manufacturing method for a secondary battery that can obtain a secondary battery with high energy density. [Means for solving the problem]

[0006] The present technology provides the following method for manufacturing a secondary battery.

[0007] [1] A process of preparing a case body having a first opening and a second opening opposite the first opening; a process of producing an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode, with a first electrode tab connected to the first electrode at a first end and a second electrode tab connected to the second electrode at a second end opposite to the first end; a process of electrically connecting a first electrode terminal provided on a first sealing plate to the first electrode tab; a process of inserting the electrode body into the case body from the second end side through the first opening after electrically connecting the first electrode terminal to the first electrode tab; and a process of inserting the electrode body into the case body. a step of electrically connecting a first electrode terminal and a second electrode tab to the first electrode terminal; a step of inserting the electrode body into a case body and then sealing the first opening with a first sealing plate; and a step of electrically connecting a second electrode terminal and the second electrode tab to the first electrode terminal and then sealing the second opening with the second sealing plate, wherein in the step of electrically connecting the first electrode terminal and the first electrode tab, the first electrode tab is electrically connected to the first electrode terminal in a curved state via a first conductive member, the first conductive member has a region that is arranged along the first sealing plate, and the first electrode tab is joined to a surface of the first conductive member that faces the electrode body in the region that is arranged along the first sealing plate.

[0008] [2] The method for manufacturing a secondary battery according to [1], wherein the first conductive member is disposed on the first sealing plate via an insulating member.

[0009] [3] The method for manufacturing a secondary battery described in [1] or [2], further comprising the step of placing a spacer between the first sealing plate and the electrode body before the step of inserting the electrode body into the case body from the second end side through the first opening after electrically connecting the first electrode terminal and the first electrode tab.

[0010] [4] The method for manufacturing a secondary battery described in [1] or [2], wherein, in the short-side direction of the first sealing plate, the first electrode terminal is offset to one side from the center of the first sealing plate, and the joint between the first conductive member and the first electrode tab is offset to the other side from the center of the first sealing plate. [Effects of the Invention]

[0011] According to the present technology, by inserting an electrode assembly into a case body having a first opening and a second opening facing each other and providing a first electrode terminal and a second electrode terminal on a first sealing plate and a second sealing plate sealing the first opening and the second opening, respectively, the height of the secondary battery can be reduced and the secondary battery can be more easily mounted in a vehicle. Furthermore, after electrically connecting the first electrode terminal and the first electrode tab, the electrode assembly is inserted into the case body through the first opening from the second end side. In other words, by attaching the first sealing plate to the first electrode tab before inserting the electrode assembly into the case body, the length of the first electrode tab can be made relatively short compared to when the first sealing plate is attached to the first electrode tab after inserting the electrode assembly into the case body. As a result, the volume occupied by the electrode assembly in the space within the case body can be increased, thereby improving the energy density of the secondary battery. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a front view of the secondary battery. [Figure 2] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow II. [Figure 3] 3 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow III. [Figure 4] 4 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow IV. FIG. [Figure 5] FIG. 2 is a front cross-sectional view of the secondary battery shown in FIG. [Figure 6] FIG. 2 is a front view showing a negative electrode blank before being formed into a negative electrode plate. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII of the negative electrode plate shown in FIG. 6. FIG. [Figure 8] FIG. 2 is a front view showing a negative electrode plate formed from a negative electrode original plate. [Figure 9] FIG. 2 is a front view showing a positive electrode plate before it is formed into a positive electrode plate. [Figure 10] 10 is a cross-sectional view taken along the line XX in FIG. 9. [Figure 11] FIG. 2 is a front view showing a positive electrode plate formed from a positive electrode original plate. [Figure 12] FIG. 2 is a diagram showing an electrode assembly and a current collector taken out from a secondary battery. [Figure 13] FIG. 2 is a diagram showing a connection structure between a negative electrode tab group and a negative electrode current collector. [Figure 14] FIG. 14 is a front view of the connection structure shown in FIG. [Figure 15] FIG. 14 is a cross-sectional view of the connection structure shown in FIG. [Figure 16] 10A and 10B are diagrams showing a process of inserting the electrode body into the case body. [Figure 17] 10A and 10B are diagrams showing a step of arranging a spacer between the sealing plate and the electrode body. [Figure 18] FIG. 10 is a cross-sectional view showing a state in which a spacer is disposed between the sealing plate and the electrode body. [Figure 19] 10A and 10B are diagrams showing modified examples of the spacer; [Figure 20] 10A and 10B are diagrams showing an example of a mechanism for pressing an electrode body via a sealing plate and a spacer. [Figure 21] FIG. 21 is a diagram showing the mechanism shown in FIG. 20 as viewed from the Z-axis direction. [Figure 22] FIG. 10 is a diagram (part 1) showing a modified example of the spacer. [Figure 23] FIG. 10 is a diagram (part 2) showing a modified example of the spacer. [Figure 24] FIG. 10 is a diagram (part 3) showing a modified example of the spacer. [Figure 25] FIG. 10 is a diagram (part 4) showing a modified example of the spacer. [Figure 26] FIG. 5 is a diagram showing a modified example of the spacer. [Figure 27] FIG. 6 is a diagram showing a modified example of the spacer. [Figure 28] FIG. 2 is a flow chart showing each step of a method for manufacturing a secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0014] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0015] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0016] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0017] In this specification, the term "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the term "electrode" may collectively refer to positive and negative electrodes. Furthermore, the term "electrode plate" may collectively refer to positive and negative plates.

[0018] (Overall battery configuration) Fig. 1 is a front view of a secondary battery 1 according to the present embodiment. Figs. 2 to 4 are views of the secondary battery 1 shown in Fig. 1 as viewed from the directions of arrows II, III, and IV, respectively. Fig. 5 is a front cross-sectional view of the secondary battery 1 shown in Fig. 1.

[0019] The secondary battery 1 can be mounted in an electric vehicle (BEV: Battery Electric Vehicle), a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a hybrid electric vehicle (HEV: Hybrid Electric Vehicle), etc. However, the use of the secondary battery 1 is not limited to being mounted in a vehicle.

[0020] 1 to 5, the secondary battery 1 includes an exterior body 100, an electrode assembly 200, and a current collector 300. The exterior body 100 includes a case main body 110, a sealing plate 121 (first sealing plate), and a sealing plate 122 (second sealing plate).

[0021] In this specification, the X-axis direction (first direction) shown in Figures 1 to 5 may be referred to as the "width direction" of the secondary battery 1 or the case body 110, the Y-axis direction (second direction) may be referred to as the "thickness direction" of the secondary battery 1 or the case body 110, and the Z-axis direction (third direction) may be referred to as the "height direction" of the secondary battery 1 or the case body 110.

[0022] When configuring a battery pack including the secondary batteries 1, multiple 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 surface of the battery pack case without using a constraining member.

[0023] The case body 110 is made of a cylindrical, preferably rectangular, member. This results in a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0024] As shown in Figures 1 and 2, sealing plates 121, 122 are provided at both ends of the case body. The case body 110 can be formed into a rectangular tube shape, for example, by abutting the edges of bent plate-like members (joint 110A shown in Figure 2) and joining them together (for example, by laser welding). The corners of the "rectangular tube" may be rounded.

[0025] In this embodiment, the case body 110 is formed so that it is longer in the width direction (X-axis direction) of the secondary battery 1 than in the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X-axis direction is preferably about 30 cm or more. This allows for the construction of a relatively large (high-capacity) secondary battery 1. The dimension (height) of the case body 110 in the Z-axis direction is preferably about 20 cm or less, more preferably about 15 cm or less, and even more preferably about 10 cm or less. This allows for the construction of a relatively low-height secondary battery 1, which improves, for example, the mountability in a vehicle.

[0026] 3, an opening 111 (first opening) is provided at one end of the case body 110. The opening 111 is sealed by a sealing plate 121. The sealing plate 121 is provided with a negative electrode terminal 131 (first electrode terminal), a liquid inlet hole 141, and a gas release valve 151. The positions of the negative electrode terminal 131, the liquid inlet hole 141, and the gas release valve 151 can be changed as appropriate. The opening 111 and the sealing plate 121 have a substantially rectangular shape with the Y-axis direction as the short side direction and the Z-axis direction as the long side direction.

[0027] 4, an opening 112 (second opening) is provided at one end of the case body 110. The opening 112 is sealed by a sealing plate 122. The sealing plate 122 is provided with a positive electrode terminal 132 (second electrode terminal), a liquid inlet hole 142, and a gas release valve 152. The positions of the positive electrode terminal 132, the liquid inlet hole 142, and the gas release valve 152 can be changed as appropriate. The opening 112 and the sealing plate 122 have a substantially rectangular shape with the Y-axis direction as the short side direction and the Z-axis direction as the long side direction.

[0028] The sealing plates 121 and 122 are made of metal. Specifically, the sealing plates 121 and 122 are made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0029] The negative electrode terminal 131 is electrically connected to the negative electrode of the electrode assembly 200. The positive electrode terminal 132 is electrically connected to the positive electrode of the electrode assembly 200.

[0030] The negative electrode terminal 131 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy. The outer surface of the negative electrode terminal 131 may be provided with a portion or layer made of aluminum or an aluminum alloy.

[0031] The positive electrode terminal 132 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy.

[0032] The liquid inlet holes 141 and 142 are sealed with a sealing member (not shown), which may be, for example, a blind rivet or other metal member.

[0033] Gas exhaust valves 151 and 152 break when the pressure inside exterior body 100 reaches or exceeds a predetermined value, and exhaust gas inside exterior body 100 to the outside.

[0034] The electrode assembly 200 is a flat-shaped electrode assembly having positive and negative electrode plates, which will be described later. Specifically, the electrode assembly 200 is a wound-type electrode assembly in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound together with a strip-shaped separator (not shown) interposed therebetween. However, in this specification, the "electrode assembly" is not limited to a wound-type electrode assembly, but may also be a stacked-type electrode assembly in which multiple positive electrode plates and multiple negative electrode plates are alternately stacked. The electrode assembly may include multiple positive electrode plates and multiple negative electrode plates, and the positive electrode tabs provided on each positive electrode plate may be stacked to form a positive electrode tab group, or the negative electrode tabs provided on each negative electrode plate may be stacked to form a negative electrode tab group.

[0035] 5, the exterior body 100 houses the electrode assembly 200. The electrode assembly 200 is housed in the exterior body 100 so that its winding axis is parallel to the X-axis direction.

[0036] Specifically, one or more wound electrode bodies are housed together with an electrolytic solution (electrolyte), not shown, inside an insulating sheet 600 (described below) disposed within the exterior housing 100. The electrolytic solution (non-aqueous electrolytic solution) may be, for example, 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, in which LiPF6 is dissolved at a concentration of 1.2 mol / L. Note that a solid electrolyte may be used instead of the electrolytic solution.

[0037] The electrode assembly 200 includes a negative electrode tab group 210A (first electrode tab group) provided at an end (first end) on the sealing plate 121 side, and a positive electrode tab group 220A (second electrode tab group) provided at an end (second end) on the sealing plate 122 side. The negative electrode tab group 210A and the positive electrode tab group 220A are connected to the negative electrode and positive electrode, respectively, of the electrode assembly 200. The negative electrode tab group 210A and the positive electrode tab group 220A are formed so as to protrude from a main body portion of the electrode assembly 200 (a portion where positive electrode plates and negative electrode plates are stacked with a separator interposed between them) toward the sealing plates 121, 122, respectively.

[0038] 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 made of a plate-shaped member. The electrode assembly 200 is electrically connected to the negative electrode terminal 131 and the positive electrode terminal 132 via the current collector 300.

[0039] The negative electrode current collector 310 is disposed on the sealing plate 121 via a resin insulating member 410. The negative electrode current collector 310 is electrically connected to the negative electrode tab group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy.

[0040] The positive electrode current collector 320 is disposed on the sealing plate 122 via a resin insulating member 420. The positive electrode current collector 320 is electrically connected to the positive electrode tab group 220A and the positive electrode terminal 132. The positive electrode current collector 320 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy. The positive electrode tab group 220A may be electrically connected to the sealing plate 122 directly or via the positive electrode current collector 320. In this case, the sealing plate 122 may also serve as the positive electrode terminal 132.

[0041] (Configuration of electrode body 200) FIG. 6 is a front view showing a negative electrode plate 210S before the negative electrode plate 210 (first electrode) is formed, FIG. 7 is a cross-sectional view taken along line VII-VII of the negative electrode plate 210S shown in FIG. 6, and FIG. 8 is a front view showing the negative electrode plate 210 formed from the negative electrode plate 210S.

[0042] The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. As shown in Figures 6 and 7, 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.

[0043] A negative electrode active material layer 212 is formed on both surfaces of the negative electrode substrate 211 except for one end portion. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater.

[0044] The negative electrode active material layer slurry is prepared by kneading graphite as the 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 approximately 98:1:1.

[0045] The negative electrode substrate 211 coated with the negative electrode active material layer slurry is dried to remove water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. The negative electrode active material layer 212 is then compressed to form a negative electrode base plate 210S including the negative electrode substrate 211 and the negative electrode active material layer 212. The negative electrode base plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode base plate 210S can be cut by laser processing using energy beam irradiation, mold processing, cutter processing, or the like.

[0046] As shown in FIG. 8, a plurality of negative electrode tabs 210B each made of a negative electrode core 211 is provided at one end in the width direction of a negative electrode plate 210 formed from a negative electrode original plate 210S. When the negative electrode plate 210 is wound, the plurality of negative electrode tabs 210B are stacked to form a negative electrode tab group 210A. The position and length in the protruding direction of each of the plurality of negative electrode tabs 210B are adjusted as appropriate, taking into account the state in which the negative electrode tab group 210A is connected to the negative electrode current collector 310. The shape of the negative electrode tabs 210B is not limited to the example shown in FIG. 8.

[0047] FIG. 9 is a front view showing a positive electrode plate 220S before the positive electrode plate 220 (second electrode) is formed, FIG. 10 is a cross-sectional view of the positive electrode plate 220S shown in FIG. 9 taken along line XX, and FIG. 11 is a front view showing a positive electrode plate 220 formed from the positive electrode plate 220S.

[0048] The positive electrode plate 220 is manufactured by processing a positive electrode original plate 220S. As shown in Figures 9 and 10, 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.

[0049] A positive electrode active material layer 222 is formed on both surfaces of the positive electrode core 221 except for one end portion. The positive electrode active material layer 222 is formed on the positive electrode core 221 by applying a positive electrode active material layer slurry using a die coater.

[0050] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as the positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium so that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material is approximately 97.5:1:1.5.

[0051] The positive electrode protective layer 223 is in contact with the positive electrode core 221 and is formed on one end of the positive electrode active material layer 222 in the width direction. The positive electrode protective layer 223 is formed on the positive electrode core 221 by applying a positive electrode protective layer slurry using a die coater. The positive electrode protective layer 223 has a larger electrical resistance than the positive electrode active material layer 222.

[0052] The positive electrode protective layer slurry is 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 is approximately 83:3:14.

[0053] The positive electrode substrate 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, thereby forming the positive electrode active material layer 222 and the positive electrode protective layer 223. The positive electrode active material layer 222 is then compressed to form a positive electrode base plate 220S including the positive electrode substrate 221, the positive electrode active material layer 222, and the positive electrode protective layer 223. The positive electrode base plate 220S is cut into a predetermined shape to form the positive electrode plate 220. The positive electrode base plate 220S can be cut by laser processing using energy beam irradiation, mold processing, cutter processing, or the like.

[0054] As shown in FIG. 11 , a plurality of positive electrode tabs 220B each made of a positive electrode core 221 is provided at one end in the width direction of a positive electrode plate 220 formed from a positive electrode original plate 220S. When the positive electrode plate 220 is wound, the plurality of positive electrode tabs 220B are stacked to form a positive electrode tab group 220A. The position and length in the protruding direction of each of the plurality of positive electrode tabs 220B are adjusted as appropriate, taking into account the state in which the positive electrode tab group 220A is connected to the positive electrode current collector 320. The shape of the positive electrode tabs 220B is not limited to the example shown in FIG. 11 .

[0055] The base of each of the positive electrode tabs 220B is provided with a positive electrode protective layer 223. The positive electrode protective layer 223 does not necessarily have to be provided at the base of the positive electrode tab 220B.

[0056] In a typical example, the thickness of the negative electrode tab 210B (one piece) is smaller than the thickness of the positive electrode tab 220B (one piece). In this case, the thickness of the negative electrode tab group 210A is smaller than the thickness of the positive electrode tab group 220A.

[0057] (Connection structure between electrode body 200 and current collector 300) Fig. 12 is a diagram showing the electrode body 200 and current collector 300 removed from the secondary battery 1. As shown in Fig. 12, the electrode body 200 is formed by stacking two electrode bodies 201 and 202, each of which is a wound electrode body. The example shown in Fig. 12 shows a structure in which two wound electrode bodies are stacked, but the electrode body 200 may be composed of one wound electrode body, three or more wound electrode bodies, or a stacked electrode body.

[0058] The negative electrode tab group 210A is joined to the negative electrode current collector 310 at a joint 310A, and the positive electrode tab group 220A is joined to the positive electrode current collector 320 at a joint 320A. The joints 310A, 320A can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, or the like. The joints 310A, 320A form conductive paths between the negative electrode tab group 210A and the positive electrode tab group 220A and the negative electrode terminal 131 and the positive electrode terminal 132.

[0059] Fig. 13 is a diagram showing a connection structure between a negative electrode tab group 210A and a negative electrode current collector 310. Fig. 14 and Fig. 15 are a front view and a cross-sectional view, respectively, of the connection structure shown in Fig. 13.

[0060] 13 to 15 , 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.

[0061] The negative electrode tab group 210A is joined to the first conductive member 311 of the negative electrode current collector 310 at a joint 310A. The first conductive member 311 is connected to the second conductive member 312 at a joint 313. The joint 313 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, caulking, or the like.

[0062] 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.

[0063] The negative electrode terminal 131 is attached to the sealing plate 121 via a resin insulating member 410A. The negative electrode terminal 131 is exposed to the outside of the sealing plate 121 and is provided so as to reach the second conductive member 312 of the negative electrode current collector 310 provided on the inside side of the sealing plate 121. The negative electrode terminal 131 and the second conductive member 312 can be connected by, for example, ultrasonic bonding, resistance welding, laser welding, or crimping. In the present embodiment, a through hole is provided in the second conductive member 312, the negative electrode terminal 131 is inserted into the through hole, the negative electrode terminal 131 is crimped onto the second conductive member 312, and then the crimped portion and the second conductive member 312 are welded at a joint 131A, thereby connecting the negative electrode terminal 131 and the second conductive member 312.

[0064] The assembly procedure for each component is as follows: first, the negative electrode terminal 131 and the second conductive member 312 are attached to the sealing plate 121 together with the insulating members 410 and 410A. Next, the first conductive member 311 connected to the electrode body 200 is attached to the second conductive member 312. At this time, the first conductive member 311 is placed on the insulating member 410 so that a portion of the first conductive member 311 overlaps the second conductive member 312. Next, the first conductive member 311 and the second conductive member 312 are welded together at the joint 313. Note that the insulating members 410 and 410A may be formed from a single member.

[0065] However, the negative electrode terminal 131 may be electrically connected to the sealing plate 121. Alternatively, the sealing plate 121 may serve as the negative electrode terminal 131.

[0066] 13 to 15 show an example of the negative electrode current collector 310 made up of two parts (the first conductive member 311 and the second conductive member 312), but the negative electrode current collector 310 may be made up of a single part.

[0067] Although the connection structure on the negative electrode side is shown in FIGS. 13 to 15, the basic connection structure on the positive electrode side is the same as that on the negative electrode side.

[0068] (Step of inserting the electrode body 200) 16 is a diagram showing a process of inserting the electrode body 200 into the case body 110. As shown in FIG. 16, an insulating sheet 600 (electrode body holder) made of resin is placed between the electrode body 200 and the case body 110.

[0069] The insulating sheet 600 may be made of, for example, resin. More specifically, the material of the insulating sheet 600 may be, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0070] The insulating sheet 600 does not necessarily have to cover the entire surface of the electrode assembly 200. The insulating sheet 600 preferably covers approximately 50% or more, and more preferably approximately 70% or more, of the area of ​​the outer surface of the electrode assembly. Of the six faces of the approximately rectangular parallelepiped (flat) electrode assembly 200, the insulating sheet 600 preferably covers the entire four faces other than at least the two faces on which the negative electrode tab group 210A and the positive electrode tab group 220A are formed.

[0071] Fig. 17 is a diagram showing a process of placing a spacer 510 between the sealing plate 121 and the electrode body 200. Fig. 18 is a cross-sectional view showing a state in which the spacer 510 has been placed between the sealing plate 121 and the electrode body 200.

[0072] 17 and 18, the negative electrode tab group 210A extending from the electrode body 200 toward the sealing plate 121 is curved from the center toward the edge in the Y-axis direction of the sealing plate 121, and then folded back toward the center. A spacer 510 is arranged to accommodate the curved negative electrode tab group 210A (curved portion).

[0073] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 are engaged with each other by sliding them along the Y-axis direction from the end side toward the center of the sealing plate 121. This fixes the spacer 510 to the sealing plate 121 via the insulating member 410, increasing the stability of the position of the spacer 510.

[0074] 18, the spacer 510 forms an internal space for accommodating the negative electrode current collector 310, and the tip portion of the negative electrode tab group 210A is also accommodated in the internal space of the spacer 510. The spacer 510 has a hole that allows the negative electrode tab group 210A to pass through.

[0075] The material of the spacer 510 is not particularly limited, but it is preferable to use an insulating material such as resin. More specifically, it is preferable to use a sheet made of polyolefin (PO). Furthermore, an insulating sheet 600 may be interposed between the spacer 510 and the electrode assembly 200.

[0076] 16 , in the method for manufacturing the secondary battery 1 according to the present embodiment, after the negative electrode terminal 131 and the negative electrode tab group 210A are electrically connected, the electrode assembly 200 is inserted into the case body 110 through the opening 111 from the end side on the positive electrode tab group 220A side. When the electrode assembly 200 is inserted to a predetermined position in the case body 110, the positive electrode tab group 220A protrudes from the opening 112 of the case body 110 to the outside of the case body 110. This allows the positive electrode terminal 132 to be connected to the positive electrode tab group 220A after the electrode assembly 200 is inserted into the case body 110.

[0077] When the negative electrode terminal 131 attached to the sealing plate 121 and the negative electrode tab group 210A are electrically connected after the electrode assembly 200 is inserted into the case body 110, the negative electrode tab group 210A is required to have a length that allows the negative electrode tab group 210A of the electrode assembly 200 housed in the case body 110 to sufficiently protrude outside the case body 110. By electrically connecting the negative electrode terminal 131 attached to the sealing plate 121 and the negative electrode tab group 210A before inserting the electrode assembly 200 into the case body 110, the length of the negative electrode tab group 210A can be reduced compared to when the connection is made after the electrode assembly 200 is inserted into the case body 110. As a result, the volume occupancy of the negative electrode plate 210 and the positive electrode plate 220 in the internal space of the case body 110 can be increased.

[0078] 16, a spacer 510 that accommodates the curved portion of the negative electrode tab group 210A is placed before the electrode body 200 is inserted into the case body 110. In this way, the curved portion of the negative electrode tab group 210A can be protected during the electrode body 200 insertion process.

[0079] 16, the electrode body 200 is inserted into the case body 110 while covered with the insulating sheet 600. This makes it possible to prevent damage to the electrode body 200 when it is inserted into the case body 110.

[0080] During the step of inserting the electrode body 200, the case body 110 can be held at a predetermined angle. As an example, it is preferable to insert the electrode body 200 while holding the case body 110 so that the X-axis direction (the width direction of the case body 110) intersects with the horizontal direction at an angle of approximately ±45° or less. For example, the electrode body 200 can be inserted into the case body 110 with the case body 110 tilted in the vertical direction so that the upper end of the opening 111, into which the electrode body 200 is inserted, is positioned higher than the upper end of the opening 112.

[0081] The step of inserting the electrode body 200 is not limited to a mode in which the electrode body 200 is pushed in from the opening 111 side, but may be a mode in which the electrode body 200 is pulled from the opening 112 side, for example.

[0082] FIG. 19 is a diagram showing a modified example of the spacer 510. In the examples of FIGS. 16 to 18, the spacer 510 is disposed over a portion of the sealing plate 121 in the height direction (Z-axis direction). However, as shown in FIG. 19, the spacer 510 may be disposed over substantially the entire height direction of the sealing plate 121. In this case, the spacer 510 may have a portion that protrudes toward the electrode assembly 200 at a position (first region) spaced apart from the negative electrode tab group 210A in the Z-axis direction relative to the vicinity of the negative electrode tab group 210A (second region). A step (preferably a step of approximately 1 mm or more) may be formed at the boundary between the first region and the second region. This can prevent damage to the negative electrode tab group 210A when the electrode assembly 200 is inserted into the case body 110.

[0083] (Mechanism for pressing the electrode body) Fig. 20 is a diagram showing an example of a mechanism for pressing the electrode body 200 via the sealing plate 121 and the spacer 510A. Fig. 21 is a diagram showing the mechanism shown in Fig. 20 as viewed from the Z-axis direction. The spacer 510A is a modified example of the spacer 510 described above.

[0084] As shown in FIGS. 20 and 21 , the spacer 510A is disposed in a position (apart from the negative electrode tab group 210A and the negative electrode current collector 310) that avoids the negative electrode tab group 210A and the negative electrode current collector 310 in the height direction (Z-axis direction) of the sealing plate 121 and the electrode assembly 200. More specifically, the spacer 510A is disposed in two separate locations so as to sandwich the negative electrode tab group 210A in the Z-axis direction. The spacer 510A preferably presses against a portion of the electrode assembly 200 where the negative electrode tab group 210A is not provided. In particular, it is preferable for the spacer 510A to press against a portion where the separator protrudes beyond the end of the negative electrode plate 210. The spacer 510A may be disposed on only one side of the negative electrode tab group 210A in the Z-axis direction. The spacer 510A can be fixed to the sealing plate 121 and / or the electrode assembly 200 by, for example, adhesive bonding, welding, or tape application. The spacer 510A may be in contact with the negative electrode tab group 210A.

[0085] It is preferable to provide a through-hole, a notch, a slit, or the like in the spacer 510A at a position facing the liquid inlet 141. It is also preferable to provide a through-hole, a notch, a slit, or the like in the spacer 510A at a position facing the gas release valve 151. This makes it possible to more reliably ensure the function of the liquid inlet 141 or the gas release valve 151.

[0086] 20 and 21, the electrode body 200 is inserted into the case body 110 by pressing the electrode body 200 via the spacer 510A. At the beginning of the insertion process of the electrode body 200, the electrode body 200 is held so that a portion of the electrode body 200 is inserted into the case body 110, and then the electrode body 200 may be further inserted by pressing the electrode body 200 via the spacer 510A.

[0087] Next, further modifications of the spacer 510A will be described with reference to FIGS.

[0088] The spacer 510B shown in Fig. 22 has two protrusions 510B1. Each of the two protrusions 510B1 has a tapered shape in which the width in the Y-axis direction decreases toward the tip. The tips of the two protrusions 510B1 are inserted between the electrode bodies 201, 202 and the inner surface of the case body 110. During the insertion process of the electrode body 200, the electrode bodies 201, 202 can be pressed into the inside of the case body 110 via the protrusions 510B1.

[0089] 23 has a protrusion 510C1. The protrusion 510C1 has a tapered shape in which the width in the Y-axis direction decreases toward the tip. The tip of the protrusion 510C1 is inserted between the electrode assemblies 201 and 202. In the process of inserting the electrode assembly 200, the electrode assemblies 201 and 202 can be pressed into the case body 110 via the protrusion 510C1.

[0090] The shapes of the protrusions 510B1 and 510C1 can be changed as appropriate. For example, the tips of the protrusions 510B1 and 510C1 may have a curved shape (R-shape).

[0091] 24 is fixed to the insulating sheet 600 at a joint 510D1. The joint 510D1 can be formed by, for example, heat welding, adhesion, fitting, taping, etc. In the process of inserting the electrode body 200, the electrode bodies 201, 202 can be pressed into the inside of the case body 110 via the spacer 510D and the insulating sheet 600.

[0092] 24 shows a structure in which insulating sheet 600 partially covers spacer 510D, but insulating sheet 600 may also be configured to completely cover spacer 510D. Also, instead of or in addition to joint 510D1 between spacer 510D and insulating sheet 600, a joint between insulating sheets 600 may be provided.

[0093] 25 also serves as an insulating part that provides insulation between the negative electrode current collector 310 and the sealing plate 121. With this configuration, the spacer 510E can more stably press the electrode body 200 during the step of inserting the electrode body 200. The spacer 510E can be fitted into a recess 121A provided in the sealing plate 121.

[0094] Two spacers 510F (FIG. 26) are arranged separately on either side of the negative electrode current collector 310. The insulating member 410 includes a first insulating member 411 (gasket) provided between the negative electrode terminal 131 and the sealing plate 121, and a second insulating member 412 provided between the negative electrode current collector 310 and the sealing plate 121. The spacer 510F fits into a recess 121A provided in the sealing plate 121.

[0095] 25 and 26, the spacers 510E, 510F can be fixed to the sealing plate 121 by a recess-and-protrusion fit between the spacers 510E, 510F and the sealing plate 121. Instead of or in addition to this recess-and-protrusion fit, other fixing means (adhesion, welding, tape, etc.) may be used. Also, latch fixing may be used.

[0096] 27 is arranged to cross the curved portion of the negative electrode tab group 210A in the Z-axis direction. In the process of inserting the electrode body 200, the electrode body 200 can be pressed into the case body 110 via the spacer 510G.

[0097] Instead of the above-described spacers, spacers may be arranged that are fixed to the electrode assembly 200. The spacers are fixed to the electrode assembly 200 by, for example, attaching tape.

[0098] (Manufacturing process of secondary battery 1) FIG. 28 is a flow chart showing each step of the manufacturing method of the secondary battery 1. As shown in FIG. 28, in S10, the case body 110 is prepared. Next, in S20, the electrode assembly 200 is fabricated. In S30, the electrode terminals provided on the sealing plates 121 and 122 are electrically connected to the electrode tab group of the electrode assembly 200. At this time, the negative electrode terminal 131 is first electrically connected to the negative electrode tab group 210A (S31), then a spacer 510 is placed between the negative electrode side sealing plate 121 and the electrode assembly 200 (S40), and further, the electrode assembly 200 is inserted into the case body 110 (S50). At this time, the positive electrode tab group 220A protrudes outside the case body 110 through the opening 112 of the case body 110. After the electrode assembly 200 is inserted into the case body 110, the positive electrode terminal 132 is electrically connected to the positive electrode tab group 220A (S32).

[0099] In the present embodiment, an example has been described in which the steps are performed in the order of connecting the negative electrode terminal 131 and the negative electrode tab group 210A (S31), inserting the electrode body 200 (S50), and connecting the positive electrode terminal 132 and the positive electrode tab group 220A (S32). However, the scope of the present technology is not limited to this, and there are also cases in which the steps are performed in the order of connecting the positive electrode terminal 132 and the positive electrode tab group 220A (S32), inserting the electrode body 200 (S50), and connecting the negative electrode terminal 131 and the negative electrode tab group 210A (S31).

[0100] After the connection between the electrode terminals and the electrode tab group (S30) is completed, the openings 111 and 112 are sealed with sealing plates 121 and 122, respectively (S60). The sealing step with sealing plates 121 and 122 is performed by, for example, laser welding.

[0101] The step (S61) of sealing the opening 111 with the negative electrode side sealing plate 121 may be performed after the step (S50) of inserting the electrode body 200 into the case body 110, and the step (S62) of sealing the opening 112 with the positive electrode side sealing plate 122 may be performed after the step (S32) of electrically connecting the positive electrode terminal 132 and the positive electrode tab group 220A.

[0102] Therefore, for example, the step (S61) of sealing opening 111 with sealing plate 121 may be performed before the step (S32) of electrically connecting positive electrode terminal 132 and positive electrode tab group 220A, or the step (S61) of sealing opening 111 with sealing plate 121 may be performed after the step (S62) of sealing opening 112 with sealing plate 122. Furthermore, at least some of the steps (S61, S62) of sealing with sealing plates 121, 122 may be performed simultaneously.

[0103] (summary) The above-described method for manufacturing the secondary battery 1 according to this embodiment can be summarized as follows.

[0104] As shown in FIG. 28, the method for manufacturing the secondary battery 1 includes the steps of: preparing a case body 110 having an opening 111 and an opening 112 opposite to the opening 111 (S10); fabricating an electrode body 200 including a negative electrode plate 210 and a positive electrode plate 220, the electrode body 200 having, at one end, a negative electrode tab group 210A including a negative electrode tab 210B connected to the negative electrode plate 210, and a positive electrode tab group 220A including a positive electrode tab 220B connected to the positive electrode plate 220 (S20); electrically connecting a negative electrode terminal 131 provided on a sealing plate 121 to the negative electrode tab group 210A (S31); the electrode body 200 is inserted into the case body 110 from the end side on the positive electrode tab group 220A side through the opening 111 (S50); the electrode body 200 is inserted into the case body 110 and then electrically connected to the positive electrode tab group 220A (S32); the electrode body 200 is inserted into the case body 110 and then electrically connected to the positive electrode terminal 132 provided on the sealing plate 122 (S61); and the electrode body 200 is inserted into the case body 110 and then electrically connected to the positive electrode terminal 132 and the positive electrode tab group 220A (S62).

[0105] In one example of a method for manufacturing a secondary battery 1, the electrode body 200 may be covered with an insulating sheet 600 before being inserted into the case body 110. However, in the present technology, the insulating sheet 600 covering the electrode body 200 is not necessarily required.

[0106] The method for manufacturing a secondary battery 1 according to an example further includes a step (S40) of arranging a spacer 510 between the sealing plate 121 and the electrode body 200. However, in the present technology, the step (S40) of arranging the spacer 510 is not necessarily required.

[0107] By disposing the spacer 510, the electrode body 200 can be inserted into the case body 110 by pressing the electrode body 200 via the spacer 510. When pressing the electrode body 200 via the spacer 510, the electrode body 200 may be pressed via the spacer 510 by pressing the sealing plate 121 from the X-axis direction, or the electrode body 200 may be pressed via the spacer 510 by moving the sealing plate 121 toward the electrode body 200 while holding it (clamping it in the Y-axis direction).

[0108] In the method for manufacturing the secondary battery 1, the electrode body 200 is held and a portion of the electrode body 200 is inserted into the case body 110, and then the electrode body 200 is pressed by the sealing plate 121 via the spacer 510, so that the electrode body 200 can be inserted into the case body 110 until the sealing plate 121 abuts against the case body 110. As a result, at least the entire portion of the electrode body 200 except for the positive electrode tab group 220A is disposed within the case body 110.

[0109] In the secondary battery 1 according to one example, in the step (S50) of inserting the electrode assembly 200 into the case body 110, the spacer 510 abuts at a position spaced apart from the negative electrode tab group 210A at the end of the electrode assembly 200 on the sealing plate 121 side. It is preferable that the spacer 510 presses the exposed portion of the separator included in the electrode assembly 200 directly or indirectly via an insulating sheet 600 or the like. However, the position at which the spacer 510 abuts against the electrode assembly 200 can be changed as appropriate. It is also not necessary for the spacer 510 to abut against the electrode assembly 200.

[0110] In this embodiment, the spacer disposed on the negative electrode side has been described, but a similar spacer may be disposed on the positive electrode side. Spacers may be disposed on both the negative electrode side and the positive electrode side, or on only one of the negative electrode side and the positive electrode side.

[0111] (Action and effect) The secondary battery 1 according to the present embodiment has a structure in which the electrode assembly 200 is inserted into a case body 110 having openings 111 and 112 facing each other, and the negative electrode terminal 131 and the positive electrode terminal 132 are respectively provided on sealing plates 121 and 122 that seal the openings 111 and 112, thereby reducing the height of the secondary battery 1 and improving the vehicle mountability of the secondary battery 1. Furthermore, after electrically connecting the negative electrode terminal 131 and the negative electrode tab group 210A, the electrode assembly 200 is inserted into the case body 110 through the opening 111 from the positive electrode tab group 220A side. In other words, by attaching the sealing plate 121 to the negative electrode tab group 210A before inserting the electrode assembly 200 into the case body 110, it is possible to form the length of the negative electrode tab group 210A relatively short compared to a case in which the sealing plate 121 is attached to the negative electrode tab group 210A after the electrode assembly 200 is inserted into the case body 110. As a result, the volume occupied by the electrode body 200 in the space inside the case body 110 can be increased, and the energy density of the secondary battery 1 can be improved.

[0112] Furthermore, in the above example, a spacer 510 is placed between the sealing plate 121 and the electrode assembly 200, and the electrode assembly 200 is inserted into the case body 110 by pressing the electrode assembly 200 via the spacer. This prevents excessive load from being applied to the negative electrode tab group 210A during the electrode assembly 200 insertion process, and can prevent damage to the negative electrode tab group 210A. Therefore, the secondary battery 1 can be manufactured more efficiently and stably.

[0113] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0114] 1 secondary battery, 100 outer casing, 110 case body, 110A joint, 111, 112 opening, 121, 122 sealing plate, 121A recess, 131 negative electrode terminal, 131A joint, 132 positive electrode terminal, 141, 142 liquid injection hole, 151, 152 gas release valve, 200, 201, 202 electrode body, 210 negative electrode plate, 210A negative electrode tab group, 210B negative electrode tab, 210S negative electrode base plate, 211 negative electrode core, 212 negative electrode active material layer, 220 positive electrode plate, 220A positive electrode tab group, 220B positive electrode tab, 220S positive electrode base plate, 221 positive electrode core, 222 positive electrode active material layer, 223 positive electrode protective layer, 300 Current collector, 310; negative electrode current collector, 310A; joint portion, 311; first conductive member, 312; second conductive member, 313; joint portion, 320; positive electrode current collector, 320A; joint portion, 410, 410A; insulating member, 411; first insulating member, 412; second insulating member, 510, 510A, 510B, 510C, 510D, 510E, 510F, 510G; spacers, 510B1, 510C1; protrusion, 510D1; joint portion, 511; first spacer, 512; second spacer, 600; insulating sheet.

Claims

1. preparing a case body having a first opening and a second opening opposite the first opening; preparing an electrode assembly including a first electrode and a second electrode having a polarity different from that of the first electrode, the electrode assembly having a first electrode tab connected to the first electrode at a first end and a second electrode tab connected to the second electrode at a second end opposite to the first end; a step of electrically connecting a first electrode terminal provided on a first sealing plate to the first electrode tab; a step of electrically connecting the first electrode terminal and the first electrode tab, and then inserting the electrode body into the case body from the second end side through the first opening; a step of electrically connecting a second electrode terminal provided on a second sealing plate to the second electrode tab after inserting the electrode body into the case body; a step of inserting the electrode body into the case body and then sealing the first opening with the first sealing plate; and sealing the second opening with the second sealing plate after electrically connecting the second electrode terminal and the second electrode tab. a first conductive member having a region that is arranged along the first sealing plate, and the first electrode tab is joined to a surface of the first conductive member that faces the electrode body and that is arranged along the first sealing plate.

2. The method for manufacturing a secondary battery according to claim 1 , wherein the first conductive member is disposed on the first sealing plate via an insulating member.

3. After electrically connecting the first electrode terminal and the first electrode tab, and before inserting the electrode body into the case body from the second end side through the first opening, 3. The method for manufacturing a secondary battery according to claim 1, further comprising the step of: disposing a spacer between the first sealing plate and the electrode body.

4. In the short-side direction of the first sealing plate, the first electrode terminal is located offset to one side from the center of the first sealing plate, The method for manufacturing a secondary battery according to claim 1 , wherein the joint between the first conductive member and the first electrode tab is located offset from the center of the first sealing plate to the other side.

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