Secondary battery and method of manufacturing secondary battery

Abstract

To provide a secondary battery that can be manufactured efficiently and stably, and a method of manufacturing the secondary battery.SOLUTION: In a secondary battery 1, a first resin member 161 is disposed between a negative electrode terminal 131 and a first sealing plate 121, the negative electrode terminal 131 and a negative electrode current collector 310 are connected to each other by a welding portion L1, the welding portion L1 extends through the negative electrode terminal 131, and the welding portion L1 is provided in the negative electrode terminal 131 on an outer side with respect to the negative electrode current collector 310. With this configuration, the negative electrode terminal 131 and a negative electrode tab group 210A can be electrically joined to each other with an electrode assembly 200 being disposed in a case main body 110. As a result, a secondary battery can be manufactured efficiently while increasing the volume energy density of the secondary battery.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present technology relates to a secondary battery and 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 battery 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] By forming a rectangular battery with a positive electrode terminal on one side of the battery case and a negative electrode terminal on the other end, it is easy to form a low-height assembled battery. However, there is room for further improvement in order to obtain a battery with a higher volumetric energy density and a secondary battery that can be produced efficiently and stably.

[0005] An object of the present technology is to provide a secondary battery that can be produced efficiently and stably, and a method for producing a secondary battery. [Means for solving the problem]

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

[0007] [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; and an exterior body that accommodates the electrode body and an electrolyte, wherein the exterior body includes a case body having a first opening at one end, and a first sealing plate that seals the first opening, the electrode body has a first electrode tab group at one end including a plurality of first electrode tabs provided on the first electrode, a first electrode current collecting member is connected to the first electrode tab group, a first electrode terminal is connected to the first electrode current collecting member, a first resin member is disposed between the first electrode terminal and the first sealing plate, the first electrode terminal and the first electrode current collecting member are connected by a welded portion, the welded portion penetrates the first electrode terminal, and the welded portion is provided in a region of the first electrode terminal that is outer than the first electrode current collecting member.

[0008] [2] The secondary battery according to [1], wherein the first sealing plate and the first resin member are joined together.

[0009] [3] The secondary battery according to [1] or [2], wherein the first electrode terminal and the first resin member are joined.

[0010] [4] The secondary battery according to any one of [1] to [3], wherein the first electrode tab group is connected to the first electrode current collecting member in a folded state, and the bonding surfaces of the first electrode tab group and the first electrode current collecting member are oriented along the first sealing plate.

[0011] [5] The secondary battery according to any one of [1] to [4], wherein the first electrode collecting member has a first region and a second region, the first region is positioned closer to the electrode body than the second region in a direction perpendicular to the first sealing plate, a first electrode terminal is connected to the first region, and a first electrode tab group is connected to the second region.

[0012] [6] The secondary battery according to any one of [1] to [5], wherein the first electrode terminal includes a first metal region made of a first metal and a second metal region made of a second metal different from the first metal.

[0013] [7] An electrode assembly including a first electrode and a second electrode having a polarity different from that of the first electrode, and an exterior body that houses the electrode assembly and an electrolyte, wherein the exterior body includes a case body having a first opening at one end and a first sealing plate that seals the first opening, the electrode assembly has a first electrode tab group at one end that includes a plurality of first electrode tabs provided on the first electrode, a first electrode current collecting member is connected to the first electrode tab group, a first electrode terminal is connected to the first electrode current collecting member, a first resin member is disposed between the first electrode terminal and the first sealing plate, and A method for manufacturing a secondary battery having a configuration in which a first electrode terminal and a first electrode current collecting member are connected by a weld, the weld penetrates the first electrode terminal, and the weld is formed in a region of the first electrode terminal that is positioned outside the first electrode current collecting member, the method comprising: an arrangement step of arranging an electrode body in a case body and sealing a first opening with a first sealing plate; and a welding step of irradiating the first electrode terminal with energy rays from the outer surface side, and welding the first electrode terminal and the first electrode current collecting member to which the first electrode tab group is connected.

[0014] [8] The method for manufacturing a secondary battery according to [7], wherein the welding step includes a step of pressing an assembly including the first sealing plate, the first resin member, and the first electrode terminal against the first electrode current collecting member to weld the first electrode terminal and the first electrode current collecting member. Effect of the Invention

[0015] According to the present technology, it is possible to provide a secondary battery that can be produced efficiently and stably, and a method for producing a secondary battery. [Brief description of the drawings]

[0016] [Figure 1] FIG. [Diagram 2] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow II. [Diagram 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. [Diagram 5] FIG. [Figure 6] FIG. 2 is an exploded perspective view of the first sealing plate. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] 2 is a front cross-sectional view of the secondary battery shown in FIG. [Figure 9] FIG. 2 is a front view showing a negative electrode original plate before the negative electrode plate is formed. [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 negative electrode plate formed from the negative electrode original plate. [Figure 12] FIG. 2 is a front view showing a positive electrode original plate before the positive electrode plate is formed. [Figure 13] 13 is a cross-sectional view of the positive electrode plate taken along line XIII-XIII of FIG. 12. [Figure 14] FIG. 2 is a front view showing a positive electrode plate formed from a positive electrode original plate. [Figure 15] FIG. 2 is a diagram showing an electrode assembly and a current collector taken out from a secondary battery. [Figure 16] FIG. 4 is a diagram showing a connection structure between a negative electrode tab group and a negative electrode current collector. [Figure 17] FIG. 17 is a cross-sectional view of the connection structure shown in FIG. [Figure 18] 11A to 11C are diagrams showing a process of inserting the electrode body into the case body. [Figure 19] FIG. 2 is a flow chart showing each step of a method for producing a secondary battery. [Figure 20] FIG. 4 is a schematic diagram showing another embodiment of a secondary battery. [Figure 21] FIG. 4 is a schematic diagram showing another embodiment of a secondary battery. [Figure 22] FIG. 4 is a schematic diagram showing another embodiment of a secondary battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 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 will not be repeated.

[0018] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0019] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0020] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, 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 one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0021] 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. In addition, the term "electrode plate" may collectively refer to positive and negative plates.

[0022] (Overall battery configuration) Fig. 1 is a front view of a secondary battery 1 according to this embodiment. Fig. 2 to Fig. 4 show the secondary battery 1 shown in Fig. 1 as viewed from the directions of arrows II, III, and IV, respectively. Fig. 5 is a perspective view of a first sealing plate 121, Fig. 6 is an exploded perspective view of the first sealing plate 121, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 5. Fig. 8 is a front cross-sectional view of the secondary battery 1 shown in Fig. 1.

[0023] 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 on a vehicle.

[0024] 1 to 4, 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 first sealing plate 121, and a second sealing plate 122.

[0025] In this specification, the X-axis direction (first direction) shown in Figs. 1 to 4 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. In addition, in the description of this disclosure, the Z-axis direction is assumed to coincide with the vertical direction. Therefore, in the secondary battery 1 shown in Fig. 1, the upper side in the figure is vertically upward, and the lower side in the figure is vertically downward. Therefore, Fig. 2 shows the state as viewed from the bottom.

[0026] When configuring an assembled battery 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 restraining member to form a battery module, or the assembled battery may be directly supported on the side surface of a battery pack case without using a restraining member.

[0027] 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.

[0028] 1 and 2, a first sealing plate 121 and a second sealing plate 122 are provided at both ends of the case body. The case body 110 can be formed into a square tube shape, for example, by abutting the edges of bent plate-like members (joint 110A shown in FIG. 2) and joining them together (for example, by laser welding). The corners of the "square tube" may have a rounded shape.

[0029] In this embodiment, the case body 110 is formed to be longer in the width direction (X-axis direction) of the secondary battery 1 than in the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the secondary battery 1.

[0030] The dimension (width) of the case body 110 in the X-axis direction is preferably about 30 cm or more. This allows a relatively large (high capacity) secondary battery 1 to be constructed. 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 a relatively low height secondary battery 1 to be constructed, improving the mountability in a vehicle, for example.

[0031] As shown in FIG. 3, a first opening 111 is provided at one end of the case body 110. The first opening 111 is sealed by a first sealing plate 121. A negative electrode terminal 131 (first electrode terminal) is provided at the first sealing plate 121. Although not shown, a gas exhaust valve and a liquid injection port may be appropriately provided at the first sealing plate 121. The first opening 111 and the first 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. The negative electrode terminal 131 may be provided flush with the first sealing plate 121, or may be provided so as to slightly protrude from the first sealing plate 121 as shown in the figure.

[0032] As shown in FIG. 4, a second opening 112 is provided at one end of the case body 110. The second opening 112 is sealed by a second sealing plate 122. A positive electrode terminal 132 (second electrode terminal) is provided at the second sealing plate 122. Although not shown, a gas exhaust valve and a liquid injection port may be appropriately provided at the first sealing plate 121. The second opening 112 and the second sealing plate 122 have a substantially rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. The positive electrode terminal 132 may be provided flush with the second sealing plate 122, or may be provided so as to slightly protrude from the second sealing plate 122 as shown in the figure.

[0033] First sealing plate 121 and second sealing plate 122 are made of metal. Specifically, first sealing plate 121 and second sealing plate 122 are made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0034] 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.

[0035] Negative electrode terminal 131 is made of a conductive material (more specifically, a metal), and preferably includes a first metal region made of a first metal and a second metal region made of a second metal different from the first metal. This can improve the reliability of the connection with the connected component. For example, the first metal region and negative electrode current collector 310 described below are preferably made of the same metal or an alloy thereof.

[0036] For example, the first metal is preferably copper or a copper alloy, the second metal is preferably aluminum or an aluminum alloy, and the negative electrode current collector 310 is preferably copper or a copper alloy. The negative electrode terminal 131 having two metal regions may be made of a clad material, or may be made of individual parts made of each metal that are integrated together by mechanical bonding, metal bonding, or both. The metal bonding may be selected from, for example, laser welding, ultrasonic bonding, friction welding, etc., but the method is not limited thereto.

[0037] More specifically, as a first example, it is preferable that the negative electrode terminal 131 includes a portion made of copper or a copper alloy and a portion made of aluminum or an aluminum alloy, the negative electrode current collector 310 made of copper or a copper alloy is connected to the portion made of copper or a copper alloy in the negative electrode terminal 131, and the portion made of aluminum or an aluminum alloy in the negative electrode terminal 131 is exposed to the outer surface side of the first sealing plate 121. As a second example, it is preferable that the negative electrode current collector 310 includes a portion made of copper or a copper alloy and a portion made of aluminum or an aluminum alloy, the negative electrode terminal 131 made of aluminum or an aluminum alloy is connected to the portion made of aluminum or an aluminum alloy in the negative electrode current collector 310, and the negative electrode tab group 210A is connected to the portion made of copper or a copper alloy in the negative electrode current collector 310.

[0038] 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.

[0039] The gas exhaust valve breaks when the pressure inside the exterior body 100 reaches or exceeds a predetermined value, and exhausts the gas inside the exterior body 100 to the outside. The liquid injection port is used as an inlet for introducing an electrolyte into the interior of the exterior body and as an exhaust port.

[0040] 7 to 9, the structure on the first sealing plate 121 side and the structure on the second sealing plate 122 side will be described. Since the structures on the first sealing plate 121 side and the second sealing plate 122 side are the same, the structure on the first sealing plate 121 side will be described here.

[0041] The structure on the first sealing plate 121 side includes the first sealing plate 121, a first resin member 161, a negative electrode terminal 131, and two negative electrode current collectors 310. When viewed from the electrode body 200 described below, the two negative electrode current collectors 310 are located closest to the electrode body 200, and the negative electrode terminal 131, the first resin member 161, and the first sealing plate 121 are stacked in this order in a direction away from the electrode body 200. Thus, the entire negative electrode terminal 131 is located outside the negative electrode current collector 310.

[0042] In this way, by positioning the two negative electrode current collectors 310 at positions closest to the electrode body 200, it is possible to efficiently manufacture a secondary battery as described below, and to obtain a secondary battery with a higher volumetric energy density.

[0043] The first sealing plate 121 has a generally rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. A rectangular first through hole 121h is provided in the generally central portion of the first sealing plate 121. The shape of the first through hole 121h is not limited to a rectangular shape, but it is preferable that the shape of the first through hole 121h matches the shape of the negative electrode terminal 131.

[0044] The first resin member 161 is disposed inside the first sealing plate 121 (on the electrode body 200 side), and has a substantially rectangular shape with the Y-axis direction as the short side direction and the Z-axis direction as the long side direction. Since it is disposed inside the first opening 111, it is designed to have dimensions smaller than the outer dimensions of the first sealing plate 121. A known resin material can be used for the first resin member 161. For example, PPS (polyphenylene sulfide), PP (polypropylene), PFA (perfluoroalkoxyalkane), PTFE (polytetrafluoroethylene), etc. are preferable.

[0045] The first resin member 161 has a first base surface 161a, a rectangular first electrode through hole 161h provided in the center of the first base surface 161a, a first annular protruding wall 161W provided to surround the first electrode through hole 161h and protruding toward the first sealing plate 121, a first surrounding wall 161b provided to surround the outer periphery of the first base surface 161a and protruding on the electrode body 200 side, and a first rib 161r extending in the longitudinal direction on the electrode body 200 side of the first base surface 161a so as to divide the short side direction into two. The first rib 161r may be provided over the entire longitudinal direction, or may be divided from the short side at a substantially central region as shown in the figure.

[0046] The first annular protruding wall 161W is located inside the first through hole 121h of the first sealing plate 121, and functions as an insulating member between the negative electrode terminal 131 and the first sealing plate 121. When the negative electrode terminal 131 is made to protrude further from the first through hole 121h of the first sealing plate 121, it is preferable that the first annular protruding wall 161W also protrudes further from the first through hole 121h.

[0047] The negative electrode terminal 131 has a first protruding electrode 131a that passes through the first through hole 121h and the first electrode through hole 161h and protrudes outward from the first sealing plate 121, and a first flange electrode 131b that is located on the electrode body 200 side of the first protruding electrode 131a and extends outward in a rectangular shape in a planar view.

[0048] The negative electrode current collector 310 has a rectangular shape accommodated in a rectangular region surrounded by the first surrounding wall 161b and the first rib 161r on the electrode body 200 side of the first resin member 161. The negative electrode current collector 310 has a first region 310a and a second region 310b, and in a direction perpendicular to the first sealing plate 121, the first region 310a is disposed closer to the electrode body 200 than the second region 310b. A step portion 310c is provided between the first region 310a and the second region 310b. By providing the step portion 310c and connecting a negative electrode tab group 210A described later to the first region 310a close to the electrode body 200 side, space saving is achieved and the mounting efficiency of the electrode body 200 can be improved.

[0049] 7, the negative electrode terminal 131 and the negative electrode current collector 310 are connected by a welded portion L1. The welded portion L1 penetrates the negative electrode terminal 131, and is provided in a region of the negative electrode terminal 131 that is outside (farther from the electrode body 200) than the negative electrode current collector 310. The welded portion L1 is provided linearly along the short side direction.

[0050] Here, the welded portion L1 is preferably joined by a molten solidified portion (a metal melted and solidified), a weld nugget, or the like, and for example, a welding method in which an energy beam is irradiated from outside, such as laser welding, is adopted. The welded portion L1 is preferably provided not on the outer peripheral edge of the first flange electrode 131b of the negative electrode terminal 131, but on a portion away from the outer peripheral edge (the first protruding electrode 131a side).

[0051] The first sealing plate 121 and the first resin member 161 are joined together. A known technique such as resin molding or adhesion is used to connect the first sealing plate 121 and the first resin member 161. The negative electrode terminal 131 and the first resin member 161 are joined together. A known technique such as resin molding or adhesion is used to connect the negative electrode terminal 131 and the first resin member 161.

[0052] Here, in order to ensure airtightness between first sealing plate 121 and first resin member 161, and between negative electrode terminal 131 and first resin member 161, it is preferable to perform a surface treatment to enhance airtightness in the area where they contact each other. The areas where they contact each other are annular area A1 and annular area A2 shown in Fig. 7. For example, the surface treatment may be a method such as chemical etching, laser processing, blast processing, or coupling processing.

[0053] The electrode body 200 is a flat-shaped electrode body having a positive electrode plate and a negative electrode plate, which will be described later. Specifically, the electrode body 200 is a wound-type electrode body in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are both wound via a band-shaped separator (not shown). However, in this specification, the "electrode body" is not limited to a wound-type electrode body, and may be a laminated electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated. The electrode body may include a plurality of positive electrode plates and a plurality of negative electrode plates, and the positive electrode tabs provided on each positive electrode plate may be laminated to form a positive electrode tab group, or the negative electrode tabs provided on each negative electrode plate may be laminated to form a negative electrode tab group.

[0054] As shown in Fig. 8, the exterior body 100 houses the electrode body 200. The electrode body 200 is housed in the exterior body 100 so that the winding axis of the electrode body 200 is parallel to the X-axis direction.

[0055] Specifically, one or more wound electrode bodies are accommodated together with an electrolytic solution (electrolyte) (not shown) inside an insulating sheet 600 (electrode body holder) described below that is arranged in the exterior body 100. As the electrolytic solution (non-aqueous electrolytic solution), for example, LiPF6 dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio (25°C) of 30:30:40 can be used. Note that a solid electrolyte may be used instead of the electrolytic solution.

[0056] The electrode body 200 includes a negative electrode tab group 210A (first electrode tab group) provided at an end (first end) on the first sealing plate 121 side, and a positive electrode tab group 220A (second electrode tab group) provided at an end (second end) on the second 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 of the electrode body 200, respectively. 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 body 200 toward the first sealing plate 121 and the second sealing plate 122.

[0057] 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 made of plate-like members as described above. The electrode body 200 is electrically connected to the negative electrode terminal 131 and the positive electrode terminal 132 via the current collector 300.

[0058] The negative electrode current collector 310 is provided on the first sealing plate 121. 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.

[0059] The structure on the first sealing plate 121 side includes the first sealing plate 121, a first resin member 161, a negative electrode terminal 131, and two negative electrode current collectors 310. When viewed from the electrode body 200 described below, the two negative electrode current collectors 310 are located at positions closest to the electrode body 200, and the negative electrode terminal 131, the first resin member 161, and the first sealing plate 121 are stacked in this order in a direction away from the electrode body 200. Thus, the entire negative electrode terminal 131 is located outside the negative electrode current collector 310.

[0060] Since the structure on the second sealing plate 122 side is the same as the structure on the first sealing plate 121 side, in FIG. 7, the first resin member 161, negative electrode terminal 131, and negative electrode current collector 310 on the first sealing plate 121 side can be replaced with the second resin member 162, positive electrode terminal 132, and positive electrode current collector 320 as the structure on the second sealing plate 122 side.

[0061] (Configuration of electrode body 200) FIG. 9 is a front view showing the negative electrode original plate 210S before the negative electrode plate 210 (first electrode) is formed, FIG. 10 is a cross-sectional view taken along line XX of the negative electrode original plate 210S shown in FIG. 9, and FIG. 11 is a front view showing the negative electrode plate 210 formed from the negative electrode original plate 210S.

[0062] The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. As shown in Figures 9 and 10, 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.

[0063] A negative electrode active material layer 212 is formed on both sides of the negative electrode core 211 except for one end portion. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry with a die coater.

[0064] 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.

[0065] The negative electrode core 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. Furthermore, the negative electrode active material layer 212 is compressed to form a negative electrode original plate 210S including the negative electrode core 211 and 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 using energy beam irradiation, die processing, cutter processing, or the like.

[0066] As shown in Fig. 11, a plurality of negative electrode tabs 210B made of a negative electrode core 211 are 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 appropriately adjusted taking into consideration 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 that exemplified in Fig. 11.

[0067] FIG. 12 is a front view showing the positive electrode original plate 220S before the positive electrode plate 220 (second electrode) is formed, and FIG. 13 is a cross-sectional view taken along line XIII-XIII of the positive electrode original plate 220S shown in FIG. 12, and FIG. 13 is a front view showing the positive electrode plate 220 formed from the positive electrode original plate 220S.

[0068] The positive electrode plate 220 is manufactured by processing a positive electrode original plate 220S. As shown in Fig. 12 and Fig. 13, 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.

[0069] A positive electrode active material layer 222 is formed on both sides 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 with a die coater.

[0070] 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.

[0071] The positive electrode protective layer 223 is in contact with the positive electrode core 221 and is formed at one end in the width direction of the positive electrode active material layer 222. The positive electrode protective layer 223 is formed on the positive electrode core 221 by applying a positive electrode protective layer slurry with a die coater. The positive electrode protective layer 223 has a larger electric resistance than the positive electrode active material layer 222.

[0072] 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.

[0073] 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 active material layer 222 is compressed to form a 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. The positive electrode original plate 220S is cut into a predetermined shape to form the positive electrode plate 220. The positive electrode original plate 220S can be cut by laser processing using energy beam irradiation, die processing, cutter processing, or the like.

[0074] As shown in Fig. 14, a plurality of positive electrode tabs 220B made of a positive electrode core 221 are 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 appropriately adjusted in consideration of 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 that exemplified in Fig. 14.

[0075] A positive electrode protection layer 223 is provided at the base of each of the positive electrode tabs 220B. The positive electrode protection layer 223 does not necessarily have to be provided at the base of the positive electrode tab 220B.

[0076] 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.

[0077] (Connection structure between electrode body 200 and current collector 300) Fig. 15 is a diagram showing the electrode body 200 and the current collector 300 taken out from the secondary battery 1. As shown in Fig. 15, the electrode body 200 has a negative electrode tab group 210A provided at one end and a positive electrode tab group 220A provided at the other end. Although this electrode body 200 shows one wound type electrode body, it may be composed of two or more wound type electrode bodies, or may be composed of a stacked type electrode body.

[0078] 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 bonding, resistance welding, laser welding, crimping, or the like.

[0079] 16 and 17 are diagrams showing a connection structure between a negative electrode tab group 210A and a negative electrode current collector 310. In the diagrams, there are two electrode bodies 200, and each negative electrode tab group 210A is joined to a second region 310b of a negative electrode current collector 310. Furthermore, a welded portion L1 is formed in the negative electrode current collector 310 by a welding method in which an energy beam is irradiated from outside, such as laser welding, and the negative electrode current collector 310 is fixed to a negative electrode terminal 131 (see FIG. 7).

[0080] As shown in FIG. 17, the negative electrode tab group 210A is connected to the second region 310b of the negative electrode current collector 310 in a folded state when housed inside the case body 110. The joint surface between the negative electrode current collector 310 and the second region 310b is arranged in a direction along the first sealing plate 121. By adopting such an arrangement, the space of the current collector is saved, and a secondary battery with a higher volumetric energy density can be obtained. When arranged in a direction along the first sealing plate 121, it is preferable that the negative electrode tab group 210A is parallel to the second region 310b, but it does not have to be strictly parallel, and for example, the inclination may be about ±45 degrees.

[0081] Although the connection structure on the negative electrode side is shown in FIG. 16 and FIG. 17, the basic connection structure on the positive electrode side is similar to that on the negative electrode side.

[0082] (Step of Inserting the Electrode Body 200) 18 is a diagram showing a process of inserting the electrode body 200 into the case body 110. As shown in FIG.

[0083] The sheet 600 may be made of, for example, resin. More specifically, the material of the sheet 600 may be, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0084] The sheet 600 does not necessarily have to cover the entire surface of the electrode body 200. The sheet 600 preferably covers an area of ​​about 50% or more, and more preferably about 70% or more, of the outer surface of the electrode body. Of the six faces of the approximately rectangular parallelepiped (flat) electrode body 200, the 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, respectively.

[0085] Although not shown, a spacer may be disposed to keep a constant space between first sealing plate 121 and electrode assembly 200. The same applies to between second sealing plate 122 and electrode assembly 200.

[0086] In the manufacturing method of the secondary battery 1 according to the present embodiment, the negative electrode tab group 210A of the electrode body 200 is joined to the second region 310b of the negative electrode current collector 310. Next, the electrode body 200 is inserted into the case body 110 through the first opening 111 from the end side on the positive electrode tab group 220A side up to a predetermined position of the case body 110.

[0087] Next, the assembly including the first sealing plate 121, the first resin member 161, and the negative electrode terminal 131 is pressed against the negative electrode current collector 310, and the negative electrode terminal 131 and the negative electrode current collector 310 are welded to form a weld L1 (see FIG. 7).

[0088] The welding may be performed using ultrasonic welding, resistance welding, laser welding, or the like.

[0089] It is preferable that the joint surface between the negative electrode tab group 210A and the second region 310b of the negative electrode current collector 310 is curved in a direction (parallel) along the first sealing plate 121 after assembly into a secondary battery. It does not have to be strictly curved, and for example, the inclination may be about ±45 degrees. Ultimately, as shown in FIG. 17, it is preferable that the negative electrode tab group 210A is curved so that the negative electrode current collector 310 is pressed against the negative electrode terminal 131 side by the elasticity of the negative electrode tab group 210A.

[0090] Next, with the electrode body 200 of the negative electrode tab group 210A placed inside the case body 110, the first sealing plate 121 is welded to the first opening 111 of the case body 110.

[0091] The welding is performed by a welding method in which energy rays, such as laser welding, are irradiated from the outside of first sealing plate 121.

[0092] When there are multiple negative electrode tab groups 210A, the bending directions of the negative electrode tab groups 210A do not necessarily have to be the same direction as shown in Fig. 17. A spacer may be disposed to keep the space between the first sealing plate 121 and the electrode body 200 constant. In this case, the negative electrode tab group 210A may be positioned inside the spacer.

[0093] For the positive electrode tab group 220A, similarly to the negative electrode tab group 210A side, the positive electrode tab group 220A is joined to the second region 320b of the positive electrode current collector 320, and an assembly including the second sealing plate 122, the second resin member 162, and the positive electrode terminal 132 is pressed against the positive electrode current collector 320, and the positive electrode terminal 132 and the positive electrode current collector 320 are welded to form a welded portion.

[0094] 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 first opening 111 side, and may be a mode in which the electrode body 200 is pulled from the second opening 112 side, for example.

[0095] (Manufacturing process of secondary battery 1) Fig. 19 is a flow diagram showing each step of the manufacturing method of the secondary battery 1. As shown in Fig. 19, in S10, the case body 110 is prepared. Next, in S20, the electrode body 200 is produced (S21), and thereafter, the electrode body 200 is covered with a sheet 600 (S22). In S30, the electrode body 200 is inserted into the case body 110 (S31).

[0096] Next, a weld L1 is provided by a welding method that irradiates an energy beam, such as laser welding, from the outside of the first opening 111 to electrically join the negative electrode terminal 131 and the negative electrode current collector 310 (S32). Similarly, on the second sealing plate 122 side, the positive electrode terminal 132 and the positive electrode current collector 320 are electrically joined.

[0097] Next, in S60, first opening 111 and second opening 112 are sealed with first sealing plate 121 and second sealing plate 122. The sealing step with first sealing plate 121 and second sealing plate 122 is performed by, for example, laser welding. Note that first opening 111 and second opening 112 may be sealed (S60) with first sealing plate 121 and second sealing plate 122 before the step of electrically joining negative electrode terminal 131 and negative electrode current collector 310 (S32) and the step of electrically connecting positive electrode terminal 132 and positive electrode current collector 320.

[0098] The step (S61) of sealing the first opening 111 with the negative electrode-side first sealing plate 121 may be performed either before or after the step (S32) of inserting the electrode body 200 into the case body 110.

[0099] As described above, the structure applied to the negative electrode side of the present disclosure can also be applied to the positive electrode side. As shown in Fig. 20, the configuration adopted in the secondary battery 1 is described as a case in which a negative electrode terminal 131 is provided on one end surface of the exterior body 100, a positive electrode terminal 132 is provided on the other end surface, and the structure shown in Fig. 7 is adopted for each terminal structure, but for example, as shown in Fig. 21, the configuration of the present disclosure may be adopted only on one end surface of the exterior body 100 (the area surrounded by A in Fig. 21), and a known connection structure may be adopted on the other end surface (the area surrounded by B in Fig. 21).

[0100] Furthermore, as shown in FIG. 22, the configuration of the present disclosure can also be adopted when the secondary battery has a negative electrode terminal 131 and a positive electrode terminal 132 provided on one side (the area surrounded by A and B in FIG. 22).

[0101] (summary) The above-mentioned contents regarding the secondary battery 1 and the manufacturing method of the secondary battery 1 according to the present embodiment can be summarized as follows.

[0102] This secondary battery 1 includes an electrode assembly 200 including a negative electrode original plate 210S and a positive electrode original plate 220S having a polarity different from that of the negative electrode original plate 210S, and an exterior body 100 that houses the electrode assembly 200 and an electrolyte, the exterior body 100 including a case body 110 having a first opening 111 at one end and a first sealing plate 121 that seals the first opening 111, and the electrode assembly 200 includes a negative electrode tab group 21 including a plurality of negative electrode tabs 210B provided on the negative electrode original plate 210S at one end. 0A, a negative electrode current collector 310 is connected to the negative electrode tab group 210A, a negative electrode terminal 131 is connected to the negative electrode current collector 310, a first resin member 161 is disposed between the negative electrode terminal 131 and the first sealing plate 121, the negative electrode terminal 131 and the negative electrode current collector 310 are connected by a weld L1, the weld L1 penetrates the negative electrode terminal 131, and the weld L1 is provided in an outer region of the negative electrode terminal 131 that is farther from the electrode body 200 than the negative electrode current collector 310.

[0103] With this configuration, the negative electrode terminal 131 and the negative electrode tab group 210A can be electrically joined with the electrode body 200 placed inside the case body 110. As a result, a secondary battery can be manufactured efficiently, and a secondary battery with a higher volumetric energy density can be obtained.

[0104] In the secondary battery 1 according to one example, the first sealing plate 121 and the first resin member 161 are joined together. In the secondary battery 1 according to one example, the negative electrode terminal 131 and the first resin member are joined together. With this configuration, the secondary battery can be manufactured more efficiently, and the secondary battery has a higher volumetric energy density.

[0105] In a secondary battery 1 according to one example, the negative electrode tab group 210A is connected to the negative electrode current collector 310 in a folded state, and the joint surface between the negative electrode tab group 210A and the negative electrode current collector 310 is oriented along the first sealing plate 121. This configuration saves space in the current collector, and a secondary battery with a higher volumetric energy density is obtained.

[0106] In the secondary battery 1 according to one example, the negative electrode current collector 310 has a first region 310a and a second region 310b, and in a direction perpendicular to the first sealing plate 121, the first region 310a is disposed closer to the electrode body 200 than the second region 310b, the negative electrode terminal 131 is connected to the first region 310a, and the negative electrode tab group 210A is connected to the second region 310b. This configuration results in a secondary battery with a higher volumetric energy density. A plurality of negative electrode current collectors 310 may be used, and a plurality of negative electrode tab groups 210A may be provided, each of which may be joined to a different negative electrode current collector 310. Note that a plurality of negative electrode tab groups 210A may be provided, and each of which may be joined to a different portion of one negative electrode current collector 310.

[0107] In the secondary battery 1 according to one example, the negative electrode terminal 131 includes a first metal region made of a first metal, and a second metal region made of a second metal different from the first metal.

[0108] The method for manufacturing this secondary battery 1 includes an arrangement step of arranging the electrode body 200 in the case body 110 and sealing the first opening 111 with the first sealing plate 121 in the secondary battery 1 having any of the configurations described above, and a welding step of irradiating the negative electrode terminal 131 with energy rays from the outer surface side and welding the negative electrode terminal 131 and the negative electrode current collector 310 to which the negative electrode tab group 210A is connected.

[0109] According to the manufacturing method of the secondary battery according to the example, the welding step includes a step of preparing an assembly 700 in which the first sealing plate 121 and the first resin member 161 are joined and the first resin member 161 and the negative terminal 131 are joined, and the negative terminal 131 and the negative current collector 310 are welded using the assembly 700. By preparing the assembly 700 in advance in this way, the components can be fixed by joining each member, rather than fixing each component by crimping the terminal as in the conventional method. As a result, the secondary battery can be manufactured stably and efficiently, the space for the current collector can be reduced, and a secondary battery with high volumetric energy density can be obtained.

[0110] (Action and effect) According to the secondary battery and the method for manufacturing the secondary battery according to the present embodiment, as described above, it is possible to efficiently manufacture the secondary battery and to improve the reliability of the joints between the components.

[0111] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as 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 scope and meaning equivalent to the claims. [Explanation of symbols]

[0112] 1 secondary battery, 100 exterior body, 110 case body, 110A, 310A, 320A joint portion, 111 first opening, 112 second opening, 121 first sealing plate, 121h first through hole, 122 second sealing plate, 131 negative electrode terminal, 131a first protruding electrode, 131b first flange electrode, 132 positive electrode terminal, 132a second protruding electrode, 132b second flange electrode, 161 first resin member, 161W first annular protruding wall, 161a first base surface, 161b first surrounding wall, 161h, 162h through hole, 161r first rib, 162 second resin member, 162W second annular protruding wall, 162a second base surface, 162b second surrounding wall, 162r second rib, 200 electrode body, 210 Negative electrode plate, 210A negative electrode tab group, 210B negative electrode tab, 210S negative electrode original 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 original 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 first region, 310b, 320a, 320b second region, 310c, 320c step portion, 320 positive electrode current collector, 600 sheet.

Claims

1. An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; an exterior body that accommodates the electrode assembly and an electrolyte; Equipped with The exterior body is a case body having a first opening at one end; a first sealing plate that seals the first opening, the electrode body has a first electrode tab group including a plurality of first electrode tabs provided on the first electrodes at one end, A first electrode current collecting member is connected to the first electrode tab group, A first electrode terminal is connected to the first electrode current collecting member, a first resin member is disposed between the first electrode terminal and the first sealing plate; the first electrode terminal and the first electrode current collecting member are connected by a welded portion, the weld portion penetrates the first electrode terminal, The welded portion is provided in a region of the first electrode terminal that is outer than the first electrode current collecting member. Secondary battery.

2. The first sealing plate and the first resin member are joined together. The secondary battery according to claim 1 .

3. The first electrode terminal and the first resin member are joined together. The secondary battery according to claim 1 .

4. the first electrode tab group is connected to the first electrode current collecting member in a folded state, a bonding surface between the first electrode tab group and the first electrode current collecting member is disposed in a direction along the first sealing plate; The secondary battery according to claim 1 .

5. the first electrode current collecting member has a first region and a second region, In a direction perpendicular to the first sealing plate, the first region is disposed at a position closer to the electrode body than the second region, The first electrode terminal is connected to the first region, the first electrode tab group is connected to the second region; The secondary battery according to claim 1 .

6. the first electrode terminal includes a first metal region made of a first metal and a second metal region made of a second metal different from the first metal; The secondary battery according to claim 1 .

7. An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; an exterior body that accommodates the electrode assembly and an electrolyte; Equipped with The exterior body is a case body having a first opening at one end; a first sealing plate that seals the first opening, the electrode body has a first electrode tab group including a plurality of first electrode tabs provided on the first electrodes at one end, A first electrode current collecting member is connected to the first electrode tab group, A first electrode terminal is connected to the first electrode current collecting member, a first resin member is disposed between the first electrode terminal and the first sealing plate; the first electrode terminal and the first electrode current collecting member are connected by a welded portion, the weld portion penetrates the first electrode terminal, the welded portion is formed in a region of the first electrode terminal that is disposed outside the first electrode current collecting member. A method for manufacturing a secondary battery having the following configuration: a disposing step of disposing the electrode body in the case body and closing the first opening with the first sealing plate; a welding step of irradiating an energy ray from an outer surface side of the first electrode terminal to weld the first electrode terminal and the first electrode current collecting member to which the first electrode tab group is connected; A method for manufacturing a secondary battery comprising the steps of:

8. The welding step includes: pressing an assembly including the first sealing plate, the first resin member, and the first electrode terminal against the first electrode current collecting member to weld the first electrode terminal and the first electrode current collecting member; The method for producing the secondary battery according to claim 7 .

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