Secondary battery and method for manufacturing secondary battery

Abstract

The invention provides a secondary battery and a method for manufacturing the secondary battery. In the secondary battery (1), a first resin member is disposed between a negative electrode terminal and a first sealing plate, the negative electrode terminal and a negative electrode current collector are connected by a welding portion, the welding portion penetrates through the negative electrode terminal, and the welding portion is provided on the negative electrode terminal at a position outside the negative electrode current collector. With this configuration, it is possible to electrically join the negative electrode terminal and the negative tab group in a state in which the electrode body is disposed within the case main body. As a result, a secondary battery can be efficiently manufactured, and a secondary battery having a higher volumetric energy density can be obtained.

Description

Technical Field

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

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

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

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

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

[0006] [1] A secondary battery, comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer body accommodating the electrode body and an electrolyte, the outer body including: a shell body having a first opening at one end thereof; and a first sealing plate for sealing the first opening, the electrode body having a first electrode sheet group at one end thereof, the first electrode sheet group including a plurality of first electrode sheets arranged on the first electrode, a first electrode current collecting component connected to the first electrode sheet group, a first electrode terminal connected to the first electrode current collecting component, a first resin component arranged between the first electrode terminal and the first sealing plate, the first electrode terminal and the first electrode current collecting component being connected by a welding portion, the welding portion penetrating the first electrode terminal, the welding portion being arranged at a region of the first electrode terminal that is outside the first electrode current collecting component.

[0007] [2] In the secondary battery described in [1], the first sealing plate is joined to the first resin member.

[0008] [3] In the secondary battery described in [1] or [2], the first electrode terminal is joined to the first resin member.

[0009] [4] In the secondary battery according to any one of [1] to [3], the first electrode sheet group is connected to the first electrode current collecting member in a bent state, and the bonding surface between the first electrode sheet group and the first electrode current collecting member is arranged along the first sealing plate.

[0010] [5] In the secondary battery described in any one of [1] to [4], the first electrode collector component has a first region and a second region, the first region is arranged closer to the electrode body than the second region in a direction perpendicular to the first sealing plate, the first region is connected to the first electrode terminal, and the second region is connected to the first electrode sheet group.

[0011] [6] In the secondary battery according to any one of [1] to [5], the first electrode terminal includes a first metal region composed of a first metal and a second metal region composed of a second metal different from the first metal.

[0012] [7] A method for manufacturing a secondary battery, wherein the secondary battery comprises: an electrode body, the electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing, the outer casing accommodating the electrode body and an electrolyte, the outer casing comprising: a shell body, the shell body having a first opening at one end thereof; and a first sealing plate, the first sealing plate sealing the first opening, the electrode body having a first electrode sheet group at one end thereof, the first electrode sheet group comprising a plurality of first electrode sheets arranged on the first electrode, a first electrode current collecting component connected to the first electrode sheet group, and a first electrode current collecting component connected to the first electrode current collecting component. The first electrode terminal has a first resin component arranged between the first electrode terminal and the first sealing plate, the first electrode terminal and the first electrode collector component are connected by a welding portion, the welding portion penetrates the first electrode terminal, and the welding portion is formed in the first electrode terminal in an area arranged at a position closer to the outside than the first electrode collector component. The manufacturing method of a secondary battery having the above structure has the following steps, namely: a configuration step, wherein the electrode body is configured in the shell body and the first opening is blocked by the first sealing plate; and a welding step, wherein the first electrode terminal is irradiated with energy lines from the outer surface side to weld the first electrode terminal and the first electrode collector component connected to the first electrode sheet group.

[0013] [8] In the method for manufacturing a secondary battery described in [7], the welding step includes the following steps: pressing the assembly including the first sealing plate, the first resin member, and the first electrode terminal against the first electrode collector member, and welding the first electrode terminal and the first electrode collector member.

[0014] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view of a secondary battery.

[0016] Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0017] Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery.

[0018] Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0019] Figure 5 This is a perspective view of the first sealing plate.

[0020] Figure 6 This is an exploded perspective view of the first sealing plate.

[0021] Figure 7 yes Figure 6 Sectional view along line VII-VII.

[0022] Figure 8 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0023] Fig. 9 It is a front view showing a negative electrode original plate before forming a negative electrode plate.

[0024] Fig.10 yes Fig. 9 XX cross-sectional view of the negative electrode original plate shown.

[0025] Fig.11 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0026] Fig.12 It is a front view showing a positive electrode original plate before forming a positive electrode plate.

[0027] Fig.13 yes Fig.12 The XIII-XIII cross-sectional view of the positive electrode original plate shown.

[0028] Fig.14 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0029] Fig.15 It is a diagram showing an electrode body and a current collector taken out from a secondary battery.

[0030] Fig.16 It is a diagram showing the connection structure between the negative electrode sheet group and the negative electrode current collector.

[0031] Fig.17 yes Fig.16 A cross-sectional view of the connection structure shown.

[0032] Fig.18 It is a diagram showing the step of inserting the electrode body into the case body.

[0033] Fig.19 It is a flowchart showing each process of the method for manufacturing a secondary battery.

[0034] Fig. 20 It is a schematic diagram showing another embodiment of a secondary battery.

[0035] Fig.21 It is a schematic diagram showing another embodiment of a secondary battery.

[0036] Fig. 22 It is a schematic diagram showing another embodiment of a secondary battery. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and the description thereof may not be repeated.

[0038] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, except for the cases where there are special records, each component is not necessarily essential to the present technology. In addition, the present technology is not necessarily limited to the technology that has all the effects mentioned in the present embodiment.

[0039] In addition, in this specification, the descriptions of "comprise", "include", and "have" are open forms. That is, when a certain structure is included, other structures other than the structure may be included or may not be included.

[0040] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships are used, such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along", etc., these terms allow for manufacturing errors or some changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0041] In this specification, "battery" is not limited to lithium-ion batteries, and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode. In addition, "electrode plate" may be collectively referred to as positive electrode plate and negative electrode plate.

[0042] (Overall structure of the battery)

[0043] Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 4 They are respectively viewed from the direction of arrow II, arrow III, and arrow IV. Figure 1 The diagram shows the state of the secondary battery 1. Figure 5 is a perspective view of the first sealing plate 121. Figure 6 is an exploded perspective view of the first sealing plate 121. Figure 7 yes Figure 5 Sectional view along line VII-VII. Figure 8 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view.

[0044] The secondary battery 1 can be mounted on an electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use.

[0045] like Figure 1 to Figure 4 As shown, the secondary battery 1 includes an outer casing 100 , an electrode body 200 , and a current collector 300 . The outer casing 100 includes a case body 110 , a first sealing plate 121 , and a second sealing plate 122 .

[0046] In this application specification, there is Figure 1 to Figure 4 The X-axis direction (first direction) shown is called the "width direction" of the secondary battery 1 or the shell body 110. Similarly, the Y-axis direction (second direction) is called the "thickness direction" of the secondary battery 1 or the shell body 110. Similarly, the Z-axis direction (third direction) is called the "height direction" of the secondary battery 1 or the shell body 110. In addition, in the description of this disclosure, the Z-axis direction is consistent with the direction of the sky and the earth. Therefore, in Figure 1 In the secondary battery 1 shown in the figure, the upper side in the figure is vertically upward, and the lower side in the figure is vertically downward. Figure 2 Indicates the state viewed from the bottom.

[0047] When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y-axis direction) by a constraining member to form a battery module, or the battery pack may be directly supported on the side of the battery pack housing without using a constraining member.

[0048] The case body 110 is formed of a cylindrical, preferably rectangular, member. This provides a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, aluminum alloy, iron, or iron alloy.

[0049] like Figure 1 , Figure 2 As shown in FIG. 1 , a first sealing plate 121 and a second sealing plate 122 are provided at both ends of the housing body. The housing body 110 is formed by, for example, bringing the ends of the plate-like members subjected to bending into contact with each other (at Figure 2 The square tube shape can be formed by joining the joint portion 110A shown in the example in FIG. 1 (e.g., laser welding) to each other. The corner of the "square tube shape" may also have an R shape.

[0050] In the present embodiment, the case body 110 is formed longer in the width direction (X-axis direction) of the secondary battery 1 than in the thickness direction (Y-axis direction) and the height direction (Z-axis direction) of the secondary battery 1 .

[0051] The dimension (width) of the shell body 110 in the X-axis direction is preferably 30 cm or more. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z-axis direction is preferably 20 cm or less, more preferably 15 cm or less, and further preferably 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0052] like Figure 3 As shown, a first opening 111 is provided at an end of one side of the shell body 110. The first opening 111 is sealed by a first sealing plate 121. A negative terminal 131 (first electrode terminal) is provided on the first sealing plate 121. Although not shown in the figure, an exhaust valve and a liquid injection port may be appropriately provided on the first sealing plate 121. The first opening 111 and the first sealing plate 121 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. The negative terminal 131 may also be arranged to be on the same surface as the first sealing plate 121, as shown in the figure, or may be arranged to protrude slightly from the first sealing plate 121.

[0053] like Figure 4As shown, a second opening 112 is provided at the other end of the shell body 110. The second opening 112 is sealed by a second sealing plate 122. A positive terminal 132 (second electrode terminal) is provided on the second sealing plate 122. Although not shown in the figure, an exhaust valve and a liquid injection port may be appropriately provided on the first sealing plate 121. The second opening 112 and the second sealing plate 122 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. The positive terminal 132 may also be arranged to be on the same surface as the second sealing plate 122, as shown in the figure, or may be arranged to protrude slightly from the second sealing plate 122.

[0054] The first sealing plate 121 and the second sealing plate 122 are made of metal. Specifically, the first sealing plate 121 and the second sealing plate 122 are made of aluminum, aluminum alloy, iron, iron alloy, or the like.

[0055] The negative electrode terminal 131 is electrically connected to the negative electrode of the electrode body 200 . The positive electrode terminal 132 is electrically connected to the positive electrode of the electrode body 200 .

[0056] The negative terminal 131 is made of a conductive material (more specifically, a metal), preferably including a first metal region made of a first metal and a second metal region made of a second metal different from the first metal. Thus, the reliability of the connection with the connected component can be improved. For example, the first metal region and the negative electrode collector 310 described later are preferably made of the same metal or an alloy thereof.

[0057] For example, copper or a copper alloy is preferred as the first metal, aluminum or an aluminum alloy is preferred as the second metal, and copper or a copper alloy is preferred as the negative electrode current collector 310. The negative electrode terminal 131 having two metal regions may be made of a cladding material, or may be made into one single component made of each metal by mechanical bonding or metal bonding, or both. Metal bonding may be selected from, for example, laser welding, ultrasonic bonding, friction welding, etc., but the construction method is not limited thereto.

[0058] More specifically, as a first example, it is preferred 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 portion made of copper or a copper alloy in the negative electrode terminal 131 is connected to the negative electrode current collector 310 made of copper or a copper alloy, and the portion made of aluminum or an aluminum alloy in the negative electrode terminal 131 is exposed on the outer surface side of the first sealing plate 121. As a second example, it is preferred 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 portion made of aluminum or an aluminum alloy in the negative electrode current collector 310 is connected to the negative electrode terminal 131 made of aluminum or an aluminum alloy, and the portion made of copper or a copper alloy in the negative electrode current collector 310 is connected to the negative electrode sheet group 210A.

[0059] The positive electrode terminal 132 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy.

[0060] The exhaust valve ruptures when the pressure in the outer casing 100 exceeds a predetermined value, and exhausts the gas in the outer casing 100 to the outside. The liquid injection port is used as an inlet for introducing electrolyte into the inner part of the outer casing and as an exhaust port.

[0061] Reference Figure 7 to Figure 9 The structure of the first sealing plate 121 side and the structure of the second sealing plate 122 side are described. Since the structures of the first sealing plate 121 side and the second sealing plate 122 side are the same, the structure of the first sealing plate 121 side is described here.

[0062] The structure on the first sealing plate 121 side includes the first sealing plate 121, the first resin member 161, the negative electrode terminal 131, and two negative electrode collectors 310. When viewed from the electrode body 200 described later, the two negative electrode 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. Therefore, the entire negative electrode terminal 131 is located outside the negative electrode collector 310.

[0063] In this way, by positioning the two negative electrode current collectors 310 closest to the electrode body 200 , the secondary battery can be efficiently manufactured as described below, and a secondary battery with a higher volume energy density can be obtained.

[0064] The first sealing plate 121 has a substantially 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 substantially central portion of the first sealing plate 121. The shape of the first through hole 121h is not limited to a rectangle, but is preferably a shape that matches the shape of the negative terminal 131.

[0065] The first resin part 161 is arranged on the inner side of the first sealing plate 121 (the electrode body 200 side), and has a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. Because it is arranged inside the first opening 111, it is designed with a size smaller than the outer dimensions of the first sealing plate 121. For the first resin part 161, a known resin material can be used. For example, PPS (polyphenylene sulfide), PP (polypropylene), PFA (perfluoroalkoxyalkane), PTFE (polytetrafluoroethylene), etc. are preferred.

[0066] The first resin member 161 includes 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 so as to surround the first electrode through hole 161h and protrude toward the first sealing plate 121, a first surrounding wall 161b provided so as to surround the outer periphery of the first base surface 161a and protrude toward the electrode body 200, and a first rib 161r extending along the long side direction so as to divide the short side direction into two on the electrode body 200 side of the first base surface 161a. The first rib 161r may be provided over the entire long side direction, or may be cut off from the short side in a substantially central region as shown in the figure.

[0067] The first annular protruding wall 161W is located inside the first through hole 121h of the first sealing plate 121, thereby functioning as an insulating member between the negative electrode terminal 131 and the first sealing plate 121. When the negative electrode terminal 131 is further protruded from the first through hole 121h of the first sealing plate 121, the first annular protruding wall 161W may also be further protruded from the first through hole 121h.

[0068] The negative terminal 131 includes: a first protruding electrode 131a, which protrudes from the first sealing plate 121 to the outside through the first through hole 121h and the first electrode through hole 161h; and a first flange electrode 131b, which is located on the side of the first protruding electrode 131a close to the electrode body 200 and extends outward into a rectangle when viewed from above.

[0069] The negative electrode collector 310 has a rectangular shape contained in a rectangular area 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 collector 310 has a first area 310a and a second area 310b, and in a direction perpendicular to the first sealing plate 121, the first area 310a is arranged at a position closer to the electrode body 200 than the second area 310b. A step portion 310c is provided between the first area 310a and the second area 310b. By providing the step portion 310c and connecting the negative electrode sheet group 210A described later to the first area 310a close to the electrode body 200 side, space saving can be achieved, thereby improving the actual installation efficiency of the electrode body 200.

[0070] like Figure 7 As shown, the negative terminal 131 and the negative current collector 310 are connected by a weld L1. The weld L1 penetrates the negative terminal 131 and is provided in a region of the negative terminal 131 that is outside the negative current collector 310 (the side away from the electrode body 200). The weld L1 is provided in a linear shape along the short side direction.

[0071] Here, it is preferred that the weld portion L1 is joined by a melt-solidified portion (a portion where the metal melts and solidifies) and a weld nugget, for example, by a welding method such as laser welding that irradiates energy lines from the outside. The weld portion L1 may not be provided at the outer peripheral edge portion of the first flange electrode 131b of the negative terminal 131, but may be provided at a portion away from the outer peripheral edge (on the first protruding electrode 131a side).

[0072] The first sealing plate 121 is joined to the first resin member 161. For the connection between the first sealing plate 121 and the first resin member 161, a known technique such as resin molding or bonding can be used. The negative electrode terminal 131 is joined to the first resin member 161. For the connection between the negative electrode terminal 131 and the first resin member 161, a known technique such as resin molding or bonding can be used.

[0073] Here, in order to ensure the airtightness between the first sealing plate 121 and the first resin member 161 and between the negative electrode terminal 131 and the first resin member 161, it is preferable to perform a surface treatment to improve the airtightness of the contact area between the two. Figure 7 The annular region A1 and the annular region A2 are shown. For example, the surface treatment includes chemical etching, laser processing, sandblasting, and coupling processing.

[0074] The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described later. Specifically, the electrode body 200 is a wound electrode body formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate together via a strip-shaped separator not shown. However, in this specification, the "electrode body" is not limited to a wound electrode body, and may also be a stacked electrode body formed by alternately stacking a plurality of positive plates and a plurality of negative plates. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets provided on each positive plate may also be stacked to form a positive electrode sheet group, and the negative electrode sheets provided on each negative plate may also be stacked to form a negative electrode sheet group.

[0075] like Figure 8 As shown, the outer casing 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the outer casing 100 so that the winding axis thereof is parallel to the X-axis direction.

[0076] Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are contained together inside an insulating sheet 600 (electrode body holder) described later and arranged in the outer casing 100. As the electrolyte (non-aqueous electrolyte), for example, an electrolyte obtained by dissolving LiPF6 at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a ratio of 30:30:40 by volume (25° C.) can be used. In addition, a solid electrolyte may be used instead of the electrolyte.

[0077] The electrode body 200 includes a negative electrode sheet group 210A (first electrode sheet group) provided at an end (first end) on the first sealing plate 121 side, and a positive electrode sheet group 220A (second electrode sheet group) provided at an end (second end) on the second sealing plate 122 side. The negative electrode sheet group 210A and the positive electrode sheet group 220A are connected to the negative electrode and the positive electrode of the electrode body 200, respectively. The negative electrode sheet group 210A and the positive electrode sheet group 220A are formed to protrude from the main body of the electrode body 200 toward the first sealing plate 121 and the second sealing plate 122.

[0078] 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 formed 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 .

[0079] 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 sheet group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy.

[0080] The structure on the first sealing plate 121 side includes the first sealing plate 121, the first resin member 161, the negative electrode terminal 131, and two negative electrode collectors 310. When viewed from the electrode body 200 described later, the two negative electrode 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 order in the direction away from the electrode body 200. Therefore, the entire negative electrode terminal 131 is located outside the negative electrode collector 310.

[0081] In addition, since the structure of the second sealing plate 122 side is the same as that of the first sealing plate 121 side, Figure 7In the embodiment, the first resin member 161 , the negative electrode terminal 131 , and the negative electrode collector 310 on the first sealing plate 121 side can be replaced with the second resin member 162 , the positive electrode terminal 132 , and the positive electrode collector 320 as the structure on the second sealing plate 122 side.

[0082] (Structure of Electrode Body 200)

[0083] Fig. 9 2 is a front view showing a negative electrode original plate 210S before forming a negative electrode plate 210 (first electrode). Fig.10 yes Fig. 9 The XX-sectional view of the negative electrode original plate 210S shown in FIG. Fig.11 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S.

[0084] The negative electrode plate 210 is manufactured by processing the negative electrode original plate 210S. Fig. 9 and Fig.10 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil.

[0085] The negative electrode core 211 has a negative electrode active material layer 212 formed thereon except for one end portion of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater.

[0086] The negative electrode active material layer slurry is prepared by kneading graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium so that the mass ratio of graphite:SBR:CMC is about 98:1:1.

[0087] The negative electrode core 211 coated with the negative electrode active material layer slurry is dried to remove the water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, the negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0088] like Fig.11As shown, at one end in the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 210B formed by the negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 210B are stacked to form a negative electrode sheet group 210A. The positions of the plurality of negative electrode sheets 210B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the negative electrode sheet group 210A is connected to the negative electrode collector 310. In addition, the shape of the negative electrode sheet 210B is not limited to Fig.11 The shape illustrated in .

[0089] Fig.12 2 is a front view showing a positive electrode original plate 220S before forming a positive electrode plate 220 (second electrode). Fig.13 yes Fig.12 The XIII-XIII cross-sectional view of the positive electrode original plate 220S shown in FIG. Fig.13 1 is a front view showing a positive electrode plate 220 formed of a positive electrode original plate 220S.

[0090] The positive electrode plate 220 is manufactured by processing the positive electrode original plate 220S. Fig.12 and Fig.13 As shown, the positive electrode original plate 220S includes a positive electrode core 221, a positive electrode active material layer 222, and a positive electrode protective layer 223. The positive electrode core 221 is an aluminum foil or an aluminum alloy foil.

[0091] The positive electrode core body 221 has a positive electrode active material layer 222 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 222 is formed on the positive electrode core body 221 by applying a positive electrode active material layer slurry using a die coater.

[0092] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding material, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium in such a manner that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material becomes approximately 97.5:1:1.5.

[0093] The positive electrode protection layer 223 is in contact with the positive electrode core 221 and is formed at one end of the positive electrode active material layer 222 in the width direction. The positive electrode protection layer 223 is formed on the positive electrode core 221 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 223 has a resistance greater than that of the positive electrode active material layer 222.

[0094] The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14.

[0095] The positive electrode core 221 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried and the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed to form the positive electrode active material layer 222 and the positive electrode protective layer 223. Furthermore, the positive electrode original plate 220S including the positive electrode core 221, the positive electrode active material layer 222 and the positive electrode protective layer 223 is formed by compressing the positive electrode active material layer 222. The positive electrode plate 220 is formed by cutting the positive electrode original plate 220S into a predetermined shape. The positive electrode original plate 220S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0096] like Fig.14 As shown, at one end in the width direction of the positive plate 220 formed by the positive original plate 220S, a plurality of positive electrode sheets 220B formed by the positive electrode core 221 are provided. When the positive plate 220 is wound, the plurality of positive electrode sheets 220B are stacked to form a positive electrode sheet group 220A. The positions of the plurality of positive electrode sheets 220B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the positive electrode sheet group 220A is connected to the positive electrode collector 320. In addition, the shape of the positive electrode sheet 220B is not limited to Fig.14 The shape illustrated in .

[0097] A positive electrode protection layer 223 is provided at the root of each of the plurality of positive electrode sheets 220B. The positive electrode protection layer 223 does not necessarily need to be provided at the root of the positive electrode sheet 220B.

[0098] In a typical example, the thickness of the negative electrode sheet 210B (one sheet) is smaller than the thickness of the positive electrode sheet 220B (one sheet). In this case, the thickness of the negative electrode sheet group 210A is smaller than the thickness of the positive electrode sheet group 220A.

[0099] (Connection Structure of Electrode Body 200 and Current Collector 300)

[0100] Fig.15 FIG. 2 is a diagram showing an electrode body 200 and a current collector 300 taken out of a secondary battery 1. Fig.15 As shown, the electrode body 200 has a negative electrode sheet group 210A at one end and a positive electrode sheet group 220A at the other end. Although one wound electrode body is shown for the electrode body 200, it may be composed of two or more wound electrode bodies or a stacked electrode body.

[0101] The negative electrode sheet group 210A is joined to the negative electrode collector 310 at the joining portion 310A, and the positive electrode sheet group 220A is joined to the positive electrode collector 320 at the joining portion 320A. The joining portions 310A and 320A can be formed by, for example, ultrasonic welding, resistance welding, laser welding, riveting, or the like.

[0102] Fig.16 and Fig.17 1 is a diagram showing the connection structure between the negative electrode sheet group 210A and the negative electrode collector 310. In the figure, there are two electrode bodies 200, and each negative electrode sheet group 210A is connected to the second region 310b of the negative electrode collector 310. In addition, the negative electrode collector 310 is formed with a welding portion L1 by a welding method such as laser welding that irradiates energy rays from the outside, thereby fixing the negative electrode collector 310 to the negative terminal 131 (see Figure 7 ).

[0103] like Fig.17 As shown, the negative electrode sheet group 210A is connected to the second region 310b of the negative electrode collector 310 in a bent state while being housed inside the shell body 110. The bonding surface between the negative electrode collector 310 and the second region 310b is arranged in the direction along the first sealing plate 121. Through such a configuration structure, space saving of the collector can be achieved, thereby obtaining a secondary battery with a higher volume energy density. In addition, when configured in the direction along the first sealing plate 121, the negative electrode sheet group 210A is preferably parallel to the second region 310b, but it may not be strictly parallel, for example, it may be inclined at about ±45 degrees.

[0104] exist Fig.16 and Fig.17 , the connection structure on the negative electrode side is shown, but the basic connection structure on the positive electrode side is also the same as that on the negative electrode side.

[0105] (Step of Inserting Electrode Body 200)

[0106] Fig.18 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.18 As shown, a resin sheet 600 (electrode body holder) is arranged between the electrode body 200 and the case body 110 .

[0107] The sheet 600 may be made of resin, for example. More specifically, the sheet 600 may be made of polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0108] The sheet 600 does not necessarily need to cover the entire surface of the electrode body 200. Preferably, the sheet 600 covers an area of ​​50% or more of the outer surface of the electrode body, and more preferably covers an area of ​​70% or more. Preferably, the sheet 600 covers the entirety of four surfaces of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for at least two surfaces each having a negative electrode sheet group 210A and a positive electrode sheet group 220A.

[0109] Although not shown, a spacer may be disposed to keep a constant space between the first sealing plate 121 and the electrode body 200 . The same applies to the space between the second sealing plate 122 and the electrode body 200 .

[0110] In the method for manufacturing secondary battery 1 of this embodiment, negative electrode sheet group 210A of electrode body 200 is joined to second region 310b of negative electrode current collector 310. Next, electrode body 200 is inserted into case body 110 from the end side on the positive electrode sheet group 220A side through first opening 111 to a predetermined position of case body 110.

[0111] 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 collector 310, and the negative electrode terminal 131 and the negative electrode collector 310 are welded to form a welded portion L1 (see Figure 7 ).

[0112] When welding is performed, ultrasonic welding, resistance welding, laser welding, or the like is used.

[0113] Preferably, the joint surface between the negative electrode sheet group 210A and the second region 310b of the negative electrode current collector 310 is bent along the direction (parallel) of the first sealing plate 121 after the secondary battery is assembled. It may not be strictly bent, for example, it may be inclined at about ±45 degrees. Fig.17 As shown, the negative electrode sheet group 210A is bent, and the negative electrode current collector 310 is pressed against the negative electrode terminal 131 side by the elastic force of the negative electrode sheet group 210A.

[0114] Next, in a state where the electrode body 200 of the negative electrode sheet group 210A is disposed in the case body 110 , the first sealing plate 121 is welded to the first opening 111 of the case body 110 .

[0115] The welding is performed from the outside of the first sealing plate 121 by a welding method using energy beams such as laser welding.

[0116] When there are multiple negative electrode sheet groups 210A, the bending direction of the negative electrode sheet group 210A does not necessarily have to be the same as Fig.17In order to keep the space between the first sealing plate 121 and the electrode body 200 constant, a separator may be disposed. In this case, the negative electrode sheet group 210A may be located inside the separator.

[0117] For the positive electrode sheet group 220A, similarly to the negative electrode sheet group 210A side, the positive electrode sheet group 220A is joined to the second region 320b of the positive electrode collector 320, the assembly including the second sealing plate 122, the second resin component 162 and the positive electrode terminal 132 is pressed against the positive electrode collector 320, and the positive terminal 132 and the positive electrode collector 320 are welded to form a welded portion.

[0118] The step of inserting the electrode body 200 is not limited to the method of pushing the electrode body 200 from the first opening 111 side, and for example, the electrode body 200 may be pulled from the second opening 112 side.

[0119] (Manufacturing process of secondary battery 1)

[0120] Fig.19 1 is a flow chart showing each step of the method for manufacturing the secondary battery 1. Fig.19 As shown, in S10, case body 110 is prepared. Next, in S20, electrode body 200 is prepared (S21), and then electrode body 200 is covered with sheet 600 (S22). In S30, electrode body 200 is inserted into case body 110 (S31).

[0121] Next, a welding portion L1 is formed from the outside of the first opening 111 by a welding method such as laser welding that irradiates energy beams, and the negative electrode terminal 131 is electrically joined to the negative electrode collector 310 (S32). Similarly, the positive electrode terminal 132 is electrically joined to the positive electrode collector 320 on the second sealing plate 122 side.

[0122] Next, in S60, the first opening 111 and the second opening 112 are sealed using the first sealing plate 121 and the second sealing plate 122. The sealing process based on the first sealing plate 121 and the second sealing plate 122 is performed, for example, by laser welding. In addition, the first opening 111 and the second opening 112 may be sealed (S60) using the first sealing plate 121 and the second sealing plate 122 before the process (S32) of electrically connecting the negative terminal 131 to the negative electrode collector 310 and the process of electrically connecting the positive terminal 132 to the positive electrode collector 320.

[0123] The step ( S61 ) of sealing the first opening 111 with the first sealing plate 121 on the negative electrode side may be performed before or after the step ( S32 ) of inserting the electrode assembly 200 into the case main body 110 .

[0124] In addition, the structure applied to the negative electrode side of the present disclosure as described above can also be applied to the positive electrode side. Fig. 20 As shown in the figure, the structure adopted by the secondary battery 1 is described as follows, that is, a negative terminal 131 is provided on one end surface of the outer casing 100, and a positive terminal 132 is provided on the other end surface, and the respective terminal structures are adopted. Figure 7 The structure shown, but for example can also be Fig.21 As shown in FIG. 1 , only one end surface of the outer casing 100 (by Fig.21 The area surrounded by A) adopts the structure disclosed in the present invention, and a well-known connection structure is adopted for the end face of the other side.

[0125] And, if Fig. 22 As shown in the figure, as a secondary battery, when a negative terminal 131 and a positive terminal 132 are provided on one side, the structure of the present disclosure (by Fig. 22 The area enclosed by A and B).

[0126] (summary)

[0127] The secondary battery 1 and the method for manufacturing the secondary battery 1 according to the present embodiment can be summarized as follows.

[0128] The secondary battery 1 includes: an electrode body 200, the electrode body 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 outer body 100, the outer body 100 accommodating the electrode body 200 and the electrolyte, the outer body 100 including: a shell body 110, the shell body 110 having a first opening 111 at one end thereof; and a first sealing plate 121, the first sealing plate 121 sealing the first opening 111, the electrode body 200 having a plurality of electrodes disposed at one end thereof A negative electrode sheet group 210A including a negative electrode sheet 210B of a negative electrode original plate 210S, a negative electrode collector 310 is connected to the negative electrode sheet group 210A, a negative electrode terminal 131 is connected to the negative electrode collector 310, a first resin component 161 is arranged between the negative terminal 131 and the first sealing plate 121, the negative terminal 131 and the negative electrode collector 310 are connected by a welding portion L1, the welding portion L1 penetrates the negative terminal 131, and the welding portion L1 is arranged in an outer area of ​​the negative terminal 131, which is farther away from the electrode body 200 than the negative electrode collector 310.

[0129] With this structure, the negative electrode terminal 131 can be electrically connected to the negative electrode sheet group 210A while the electrode body 200 is disposed in the case body 110. As a result, the secondary battery can be efficiently manufactured, and a secondary battery with a higher volume energy density can be obtained.

[0130] In one example of the secondary battery 1, the first sealing plate 121 is bonded to the first resin member 161. In one example of the secondary battery 1, the negative electrode terminal 131 is bonded to the first resin member. With this structure, the secondary battery can be manufactured more efficiently and has a higher volume energy density.

[0131] In one example of the secondary battery 1, the negative electrode sheet group 210A is connected to the negative electrode collector 310 in a bent state, and the bonding surface between the negative electrode sheet group 210A and the negative electrode collector 310 is arranged along the first sealing plate 121. With this structure, the space of the current collector can be saved, so that a secondary battery with a higher volume energy density can be obtained.

[0132] In a secondary battery 1 of one example, the negative electrode collector 310 has a first region 310a and a second region 310b. In a direction perpendicular to the first sealing plate 121, the first region 310a is arranged at a position closer to the electrode body 200 than the second region 310b. The negative terminal 131 is connected to the first region 310a, and the negative electrode sheet group 210A is connected to the second region 310b. With this structure, a secondary battery with a higher volume energy density is achieved. It is also possible to use multiple negative electrode collectors 310 and set multiple negative electrode sheet groups 210A so that the multiple negative electrode sheet groups 210A are respectively joined to different negative electrode collectors 310. In addition, it is also possible to set multiple negative electrode sheet groups 210A and make them respectively joined to different parts of one negative electrode collector 310.

[0133] In one example of the secondary battery 1 , 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.

[0134] The manufacturing method of the secondary battery 1 comprises: a configuration step, in which, in a secondary battery 1 having any of the structures described above, an electrode body 200 is configured in a shell body 110, and the first opening 111 is blocked by a first sealing plate 121; and a welding step, in which an energy line is irradiated from the outer surface side to the negative terminal 131, and the negative terminal 131 and the negative electrode collector 310 connected to the negative electrode sheet group 210A are welded.

[0135] According to a manufacturing method of a secondary battery of one example, the welding process includes a process of preparing an assembly 700 formed by joining the first sealing plate 121 with the first resin component 161 and the first resin component 161 with the negative terminal 131, and welding the negative terminal 131 and the negative electrode collector 310 using the assembly 700. By preparing the assembly 700 in advance in this way, it is possible to fix the components by joining the components instead of using the riveting of the terminal as in the past. As a result, it is possible to manufacture stably and efficiently, and the space of the collector can be reduced, so that a secondary battery with high volume energy density can be obtained.

[0136] (Function and Effect)

[0137] According to the secondary battery and the method for manufacturing the secondary battery of the present embodiment, as described above, the secondary battery can be efficiently manufactured and the reliability of the joints of the components can be improved.

[0138] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, It is characterized in that have: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing that houses the electrode body and the electrolyte, The outer casing comprises: a housing body having a first opening at one end thereof; and a first sealing plate for sealing the first opening, The electrode body has a first electrode sheet group at one end thereof, the first electrode sheet group including a plurality of first electrode sheets provided on the first electrode. A first electrode current collecting member is connected to the first electrode sheet group. The first electrode current collecting member is connected to a first electrode terminal. 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 via a welding portion, The welding portion penetrates the first electrode terminal, The welding portion is provided in a region of the first electrode terminal that is located outside the first electrode current collecting member.

2. The secondary battery according to claim 1, It is characterized in that The first sealing plate is bonded to the first resin member.

3. The secondary battery according to claim 1, It is characterized in that The first electrode terminal is joined to the first resin member.

4. The secondary battery according to claim 1, It is characterized in that The first electrode sheet group is connected to the first electrode current collecting member in a bent state. The bonding surface between the first electrode sheet group and the first electrode current collecting member is arranged along the first sealing plate.

5. The secondary battery according to claim 1, It is characterized in that The first electrode current collecting member has a first region and a second region, The first region is arranged at a position closer to the electrode body than the second region in a direction perpendicular to the first sealing plate. The first region is connected to the first electrode terminal. The first electrode sheet group is connected to the second region.

6. The secondary battery according to any one of claims 1 to 5, It is characterized in that The first electrode terminal includes a first metal region formed of a first metal and a second metal region formed of a second metal different from the first metal.

7. A method for manufacturing a secondary battery, It is characterized in that The secondary battery has: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing that houses the electrode body and the electrolyte, The outer casing comprises: a housing body having a first opening at one end thereof; and a first sealing plate for sealing the first opening, The electrode body has a first electrode sheet group at one end thereof, the first electrode sheet group including a plurality of first electrode sheets provided on the first electrode. The first electrode sheet group is connected to a first electrode current collecting member. The first electrode current collecting member is connected to a first electrode terminal. 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 via a welding portion, The welding portion penetrates the first electrode terminal, The welding portion is formed in a region of the first electrode terminal disposed outside the first electrode current collecting member. The method for manufacturing the secondary battery having the above structure comprises the following steps, namely: a disposing step of disposing the electrode body in the housing body and blocking the first opening with the first sealing plate; and The welding step irradiates the first electrode terminal with an energy beam from the outer surface side to weld the first electrode terminal and the first electrode current collecting member to which the first electrode sheet group is connected.

8. The method for manufacturing a secondary battery according to claim 7, It is characterized in that 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, and welding the first electrode terminal and the first electrode current collecting member.

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