Secondary battery and method for manufacturing the same

Abstract

A secondary battery in which an electrode body having a positive electrode connector group at one end is housed in a battery case, wherein a first positive electrode collector has a first region arranged between a sealing plate and the electrode body, and a second region arranged between a first side wall of a square outer packaging body constituting the battery case and the electrode body, the positive electrode connector group is connected to the second positive electrode collector in a bent state, and the second positive electrode collector is welded to the second region.

Description

Technical Field

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

[0002] Secondary batteries such as alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used as power sources for driving electric vehicles (EVs), hybrid electric vehicles (HEVs, PHEVs), and the like.

[0003] In these secondary batteries, a battery case is formed by an outer package having an opening and a bottomed cylindrical shape, and a sealing plate for sealing the opening. An electrode body consisting of a positive plate, a negative plate and a separator is contained in a battery case together with an electrolyte. A positive terminal and a negative terminal are mounted on the sealing plate. The positive terminal is electrically connected to the positive plate via a positive current collector, and the negative terminal is electrically connected to the negative plate via a negative current collector.

[0004] As such a secondary battery, a secondary battery has been proposed, which includes an electrode group in which a positive electrode and a negative electrode are wound with a separator therebetween, current collecting tabs are formed at both ends of the electrode group, and the current collecting tabs are welded to leads while being bent in a direction extending relative to the winding axis of the electrode group (Patent Document 1 below).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-14881 Summary of the invention

[0008] Means used to solve problems

[0009] A secondary battery according to one embodiment of the present invention includes:

[0010] An electrode body including a positive electrode plate and a negative electrode plate,

[0011] A square outer packaging body having an opening and accommodating the electrode body,

[0012] The sealing plate for sealing the opening, and

[0013] The terminal mounted on the sealing plate,

[0014] The electrode body has a positive electrode connector at one end and a negative electrode connector at the other end.

[0015] The square outer packaging body has a bottom, a pair of first side walls arranged in mutually opposing directions, and a pair of second side walls arranged in mutually opposing directions.

[0016] The positive electrode connector group or the negative electrode connector group is electrically connected to the terminal via a first current collector and a second current collector.

[0017] The first current collector includes a first region disposed between the sealing plate and the electrode body, and a second region bent from an end of the first region and disposed between the first side wall on one side and the electrode body.

[0018] The positive electrode tab group or the negative electrode tab group is connected to the second current collector in a bent state.

[0019] The second current collector is welded to the second region.

[0020] According to the configuration of a secondary battery according to one embodiment of the present invention, a secondary battery has a higher volume energy density and an easy-to-assemble structure.

[0021] It can be configured as follows:

[0022] comprising a plurality of the above-mentioned electrode bodies,

[0023] The plurality of second current collectors connected to the respective positive electrode tab groups or the negative electrode tab groups of the plurality of electrode bodies are welded to the second region of the first current collector.

[0024] It can be configured as follows:

[0025] The positive electrode terminal group or the negative electrode terminal group provided in one of the electrode bodies is divided into a plurality of groups.

[0026] The second current collector is provided with a plurality of the second current collectors connected to the plurality of the positive electrode tab groups or the plurality of the negative electrode tab groups, respectively.

[0027] The plurality of second current collectors are welded to the second region of the first current collector.

[0028] It can be configured as follows:

[0029] The second current collector includes a second region connecting portion and a tab connecting portion,

[0030] The second region connecting portion is welded to the second region.

[0031] The positive electrode connector group or the negative electrode connector group is connected to the connector connection portion.

[0032] A distance between the first side wall on one side and the joint connecting portion is smaller than a distance between the first side wall on one side and the second region connecting portion.

[0033] It can be configured as follows:

[0034] The second current collector is provided with a recessed portion.

[0035] A through hole is provided inside the recessed portion.

[0036] The second current collector is welded to the second region inside the recess.

[0037] It can be configured as follows:

[0038] The second current collector has a plate-shaped region arranged along one side of the first side wall.

[0039] The positive electrode tab group or the negative electrode tab group is connected to a surface of the plate-shaped region that is located on the electrode body side.

[0040] It can be configured as follows:

[0041] Notches are provided at both ends of the second region in the width direction.

[0042] It can be configured as follows:

[0043] In the second current collector, a fuse portion is provided between a welded portion between the second current collector and the second region and a joined portion between the second current collector and the positive electrode tab group or the negative electrode tab group.

[0044] It can be configured as follows:

[0045] At least one of the positive electrode tab group and the negative electrode tab group is provided at a position offset toward the sealing plate in the electrode body.

[0046] A method for manufacturing a secondary battery according to one embodiment of the present invention is a method for manufacturing a secondary battery, wherein the secondary battery comprises:

[0047] An electrode body including a positive electrode plate and a negative electrode plate,

[0048] A square outer packaging body having an opening and accommodating the electrode body,

[0049] The sealing plate for sealing the opening, and

[0050] The terminal mounted on the sealing plate,

[0051] The electrode body has a positive electrode connector at one end and a negative electrode connector at the other end.

[0052] The square outer packaging body has a bottom, a pair of first side walls arranged in mutually opposing directions, and a pair of second side walls arranged in mutually opposing directions.

[0053] The positive electrode connector group or the negative electrode connector group is electrically connected to the terminal via a first current collector and a second current collector.

[0054] The manufacturing method of the secondary battery has the following steps:

[0055] The step of installing the first current collector on the sealing plate;

[0056] A step of connecting the positive electrode tab assembly or the negative electrode tab assembly to the second current collector;

[0057] a step of bending the positive electrode tab assembly or the negative electrode tab assembly and changing the orientation of the second current collector connected to the positive electrode tab assembly or the negative electrode tab assembly; and

[0058] A step of welding the second current collector to which the positive electrode tab group or the negative electrode tab group is connected to the first current collector attached to the sealing plate.

[0059] According to the method for manufacturing a secondary battery according to one embodiment of the present invention, a secondary battery having a higher volume energy density can be easily manufactured.

[0060] It can be configured as follows:

[0061] The first current collector includes a first region disposed between the sealing plate and the electrode body, and a second region bent from an end of the first region and disposed between the first side wall on one side and the electrode body.

[0062] The second current collector to which the positive electrode tab group or the negative electrode tab group is connected is welded to the second region.

[0063] It can be configured as follows:

[0064] The second current collector is provided with a recessed portion.

[0065] A through hole is provided in the recessed portion.

[0066] The second current collector is welded in the second region by irradiating the recess with high energy rays.

[0067] It can be configured as follows:

[0068] Notches are provided at both ends of the second region in the width direction.

[0069] The second current collector is welded to the second region while the notch portion is held.

[0070] It can be configured as follows:

[0071] The above terminal is the negative terminal,

[0072] The first current collector is a first negative electrode current collector.

[0073] The first region is the negative electrode first region.

[0074] The second region is the negative electrode second region.

[0075] The second current collector is a second negative electrode current collector.

[0076] further comprising a first positive electrode current collector and a second positive electrode current collector,

[0077] The first positive electrode current collector includes: a positive electrode first region disposed between the sealing plate and the electrode body, and a positive electrode second region disposed between the other first side wall and the electrode body.

[0078] The process is as follows:

[0079] The step of installing the first positive electrode current collector on the sealing plate;

[0080] A step of connecting the positive electrode terminal assembly to the second positive electrode current collector;

[0081] The step of bending the positive electrode tab assembly and changing the orientation of the second positive electrode current collector connected to the positive electrode tab assembly;

[0082] The step of disposing the positive electrode second region of the first positive electrode collector mounted on the sealing plate and the negative electrode second region of the first negative electrode collector mounted on the sealing plate between the second positive electrode collector connected to the positive electrode tab group and the second negative electrode collector connected to the negative electrode tab group;

[0083] A step of reducing the distance between the second positive electrode current collector and the second negative electrode current collector;

[0084] The step of welding the positive electrode second region to the second positive electrode current collector and welding the negative electrode second region to the second negative electrode current collector.

[0085] According to the present invention, a secondary battery having a higher volume energy density can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] [ Figure 1 ] Figure 1 It is a perspective view of a secondary battery according to an embodiment.

[0087] [ Figure 2 ] Figure 2 It is along Figure 1 A cross-sectional view of a secondary battery taken along line II-II.

[0088] [ Figure 3A ] Figure 3AThe figure shows the outer surface side of the battery to which the positive electrode terminal, the negative electrode terminal, the first positive electrode collector, and the first negative electrode collector are attached.

[0089] [ Figure 3B ] Figure 3B The figure shows the inner surface side of the battery to which the positive electrode terminal, the negative electrode terminal, the first positive electrode collector, and the first negative electrode collector are attached.

[0090] [ Figure 4 ] Figure 4 It is a top view of the positive electrode plate according to the embodiment.

[0091] [ Figure 5 ] Figure 5 It is a plan view of the negative electrode plate according to the embodiment.

[0092] [ Figure 6 ] Figure 6 It is a top view of the electrode body according to the embodiment.

[0093] [ Fig. 7A ] Fig. 7A It is a plan view of a second positive electrode current collector according to the embodiment.

[0094] [ Figure 7B ] Figure 7B It is along Fig. 7A A cross-sectional view of the second positive electrode current collector taken along line VIIB-VIIB in FIG.

[0095] [ Figure 8 ] Figure 8 It is a cross-sectional view showing a state where a positive electrode tab group is connected to the second positive electrode current collector.

[0096] [ Fig. 9 ] Figure 8 It is a perspective view of an electrode body to which a second positive electrode current collector and a second negative electrode current collector are attached.

[0097] [ Fig.10 ] Fig.10 It is a cross-sectional view of the vicinity of the connection portion between the second positive electrode current collector and the positive electrode tab group, and is a view showing a state where the positive electrode tab group is bent and fixed.

[0098] [ Fig.11 ] Fig.11 It is a perspective view of an electrode body group including a plurality of electrode bodies.

[0099] [ Fig. 12A ] Fig. 12A This is a diagram showing a state where the first positive electrode collector and the first negative electrode collector are arranged between the second positive electrode collector and the second negative electrode collector.

[0100] [ Fig. 12B ] Fig. 12B This is a diagram showing a state where the distance between the second positive electrode current collector and the second negative electrode current collector is reduced.

[0101] [ Fig. 12C ] Fig. 12C This is a diagram showing a state where the first positive electrode current collector is connected to the second positive electrode current collector, and the first negative electrode current collector is connected to the second negative electrode current collector.

[0102] [ Fig.13 ] Fig.13 It is a perspective view of the sealing plate and the electrode assembly group after the first positive electrode collector and the second positive electrode collector are connected, and the first negative electrode collector and the second negative electrode collector are connected.

[0103] [ Fig.14 ] Fig.14 It is a development view of the electrode body holder according to the embodiment.

[0104] [ Fig.15 ] Fig.15 It is a cross-sectional view of the vicinity of the connection portion between the second positive electrode current collector and the positive electrode tab group in another embodiment, and is a view showing a state where the positive electrode tab group is bent and fixed.

[0105] [ Fig.16 ] Fig.16 It is a cross-sectional view showing a state where a positive electrode tab group is connected to a second positive electrode current collector in another embodiment.

[0106] [ Fig.17 ] Fig.17 It is a cross-sectional view of the vicinity of the connection portion between the second positive electrode current collector and the positive electrode tab group in another embodiment, and is a view showing a state where the positive electrode tab group is bent and fixed.

[0107] [ Fig.18 ] Fig.18 This is a diagram showing a state in which a second positive electrode current collector is connected to a first positive electrode current collector in another embodiment. DETAILED DESCRIPTION

[0108] The configuration of the secondary battery 20 according to the embodiment will be described below. It should be noted that the present invention is not limited to the following embodiment.

[0109] Figure 1 and Figure 2The secondary battery 20 shown has a battery case 100, which includes a square outer package 1 with an opening and a bottomed square tube, and a sealing plate 2 that seals the opening of the square outer package 1. The square outer package 1 has a bottom 1a, a pair of first side walls 1b, 1c, and a pair of second side walls 1d, 1e. A pair of first side walls 1b, 1c are arranged in mutually opposing directions, and a pair of second side walls 1d, 1e are arranged in mutually opposing directions. The area of ​​a pair of first side walls 1b, 1c is smaller than the area of ​​a pair of second side walls 1d, 1e. The square outer package 1 and the sealing plate 2 are preferably made of metal, more preferably aluminum or iron. The electrode body 3 including the positive electrode plate 4 and the negative electrode plate 5 is contained in the square outer package 1 together with the electrolyte. The electrode body 3 involved in the embodiment is a flat wound electrode body in which a strip-shaped positive electrode plate 4 and a strip-shaped negative electrode plate 5 are wound with a strip-shaped separator. In the electrode body 3 , a positive electrode tab group 40 is provided at one end portion in the direction in which the winding axis extends, and a negative electrode tab group 50 is provided at the other end portion in the direction in which the winding axis extends.

[0110] A positive terminal 8 and a negative terminal 9 are mounted on the sealing plate 2. The positive electrode tab group 40 is electrically connected to the positive terminal 8 via the positive electrode collector 6. The positive electrode collector 6 includes a first positive electrode collector 61 and a second positive electrode collector 62. The negative electrode tab group 50 is electrically connected to the negative terminal 9 via the negative electrode collector 7. The negative electrode collector 7 includes a first negative electrode collector 71 and a second negative electrode collector 72.

[0111] The positive electrode connector group 40 includes a plurality of positive electrode connectors 4b. The second positive electrode collector 62 has an area arranged along the first side wall 1b of the square outer package 1. The positive electrode connector group 40 is connected to the area of ​​the second positive electrode collector 62 arranged along the first side wall 1b in a bent state. The second positive electrode collector 62 has a plate-like area arranged along the first side wall 1b of the square outer package 1, and the positive electrode connector group 40 is connected to the surface of the electrode body 3 side of the plate-like area. The inclination of the plate-like area relative to the first side wall 1b is preferably less than ±30°, more preferably less than ±15°, and further preferably less than ±10°. The plate-like area is more preferably substantially parallel to the first side wall 1b (for example, the inclination of the plate-like area relative to the first side wall 1b is within ±5°).

[0112] The negative electrode connector group 50 includes a plurality of negative electrode connectors 5b. The second negative electrode current collector 72 has an area arranged along the first side wall 1c of the square outer package 1. The negative electrode connector group 50 is connected to the area of ​​the second negative electrode current collector 72 arranged along the first side wall 1c in a bent state. The second negative electrode current collector 72 has a plate-like area arranged along the first side wall 1c of the square outer package 1, and the negative electrode connector group 50 is connected to the surface of the electrode body 3 side of the plate-like area. The inclination of the plate-like area relative to the first side wall 1c is preferably less than ±30°, more preferably less than ±15°, and further preferably less than ±10°. The plate-like area is more preferably substantially parallel to the first side wall 1c (for example, the inclination of the plate-like area relative to the first side wall 1b is within ±5°).

[0113] An outer insulating member 10 made of resin is arranged between the sealing plate 2 and the positive electrode terminal 8. An inner insulating member 11 made of resin is arranged between the sealing plate 2 and the first positive electrode collector 61. An outer insulating member 12 made of resin is arranged between the sealing plate 2 and the negative electrode terminal 9. An inner insulating member 13 made of resin is arranged between the sealing plate 2 and the first negative electrode collector 71.

[0114] The electrode body 3 is arranged inside an electrode body holder 14 formed by folding a resin insulating sheet into a box or bag shape.

[0115] The sealing plate 2 is provided with an electrolyte injection hole 15, which is sealed by a sealing member 16. The sealing plate 2 is provided with a gas discharge valve 17 which ruptures when the pressure in the battery case 100 exceeds a predetermined value to discharge the gas in the battery case 100.

[0116] Next, a method for manufacturing the secondary battery 20 and details of each structure will be described.

[0117] [Attachment of the terminal and the first current collector to the sealing plate]

[0118] The sealing plate 2 has a positive terminal mounting hole near one end and a negative terminal mounting hole near the other end. An external insulating component 10 is arranged on the outer surface side around the positive terminal mounting hole of the sealing plate 2, and an internal insulating component 11 and a first positive electrode collector 61 are arranged on the inner surface side around the positive terminal mounting hole of the sealing plate 2. In addition, the positive terminal 8 is inserted from the outside of the battery into the through hole of the external insulating component 10, the positive terminal mounting hole of the sealing plate 2, the through hole of the internal insulating component 11, and the through hole of the first positive electrode collector 61, and the positive terminal 8 is riveted to the first positive electrode collector 61. In addition, it is more preferable to weld the riveted portion of the positive terminal 8 to the first positive electrode collector 61.

[0119] An external insulating member 12 is arranged on the outer surface side around the negative terminal mounting hole of the sealing plate 2, and an internal insulating member 13 and a first negative electrode collector 71 are arranged on the inner surface side around the negative terminal mounting hole of the sealing plate 2. Then, the negative terminal 9 is inserted from the outside of the battery into the through hole of the external insulating member 12, the negative terminal mounting hole of the sealing plate 2, the through hole of the internal insulating member 13, and the through hole of the first negative electrode collector 71, and the negative terminal 9 is riveted to the first negative electrode collector 71. In addition, it is more preferable to weld the riveted portion of the negative terminal 9 to the first negative electrode collector 71.

[0120] Figure 3A and Figure 3B It is a perspective view of the sealing plate 2 to which the positive electrode terminal 8 , the first positive electrode current collector 61 , the negative electrode terminal 9 , and the first negative electrode current collector 71 are attached. Figure 3A Indicates the external side of the battery, Figure 3B Indicates the internal side of the battery.

[0121] The first positive electrode current collector 61 has a first region 61a arranged along the sealing plate 2, and a second region 61b bent from the end of the first region 61a. In the state of the secondary battery 20, the first region 61a is arranged between the sealing plate 2 and the electrode body 3. The second region 61b extends from the first region 61a to the bottom 1a of the square outer package 1. The second region 61b is arranged between the first side wall 1b of the square outer package 1 and the electrode body 3.

[0122] The first negative electrode current collector 71 has a first region 71a arranged along the sealing plate 2, and a second region 71b bent from the end of the first region 71a. In the state of the secondary battery 20, the first region 71a is arranged between the sealing plate 2 and the electrode body 3. The second region 71b extends from the first region 71a to the bottom 1a of the square outer package 1. The second region 71b is arranged between the first side wall 1c of the square outer package 1 and the electrode body 3.

[0123] In the second region 61b of the first positive electrode collector 61, it is preferred to provide notch portions 61c at both ends in the width direction. When the second region 61b is connected to the second positive electrode collector 62 described later, by holding the notch portion 61c, welding can be performed more stably, and a higher quality joint can be stably formed. The notch portion 61c is preferably arranged on the bottom 1a side of the square outer package 1 in the second region 61b compared to the above-mentioned internal insulating component 11. The notch portion 61c is preferably provided near the end of the first region 61a side in the second region 61b. It should be noted that it is also preferred to provide notch portions 71c at both ends in the width direction for the second region 71b of the first negative electrode collector 71. In the case where the internal insulating component 11 has a wall portion covering a portion of the second region 61b, it is preferred that the notch portion 61c has an area not covered by the wall portion of the internal insulating component 11.

[0124] The positive terminal 8 and the first positive electrode collector 61 are preferably made of metal, more preferably aluminum. The negative terminal 9 and the first negative electrode collector 71 are preferably made of metal, more preferably copper. It should be noted that the negative terminal 9 may include an area composed of aluminum and an area composed of copper. In this case, it is preferred that the area composed of copper is connected to the first negative electrode collector 71 made of copper, so that the area composed of aluminum is exposed on the outside of the battery.

[0125] [Positive plate]

[0126] First, a method for manufacturing a positive electrode plate will be described.

[0127] [Preparation of positive electrode active material layer slurry]

[0128] Lithium nickel cobalt manganese composite oxide as a 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 are mixed in a mass ratio of lithium nickel cobalt manganese composite oxide: PVdF: carbon material to be 97.5:1:1.5 to prepare a positive electrode active material layer slurry.

[0129] [Preparation of positive electrode protective layer slurry]

[0130] Alumina powder, a carbon material as a conductive material, polyvinylidene fluoride (PVdF) as a binder, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium were mixed so that the mass ratio of alumina powder:carbon material:PVdF was 83:3:14 to prepare a protective layer slurry.

[0131] [Formation of Positive Electrode Active Material Layer and Positive Electrode Protective Layer]

[0132] As a positive electrode core, the positive electrode active material layer slurry and the positive electrode protective layer slurry prepared by the above method are applied on both sides of the aluminum foil by a die coater. At this time, the positive electrode active material layer slurry is applied to the center of the width direction of the positive electrode core. In addition, the positive electrode protective layer slurry is applied to the ends of the width direction of the area coated with the positive electrode active material layer slurry.

[0133] The positive electrode core coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried to remove the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry. The positive electrode active material layer and the positive electrode protective layer are thereby formed. Thereafter, the positive electrode active material layer is compressed to form a positive electrode original plate. The positive electrode original plate is cut into a predetermined shape as a positive electrode plate 4. It should be noted that the cutting of the positive electrode original plate can be performed by irradiating energy rays such as lasers, molds, or cutters.

[0134] Figure 4 It is a top view of the positive electrode plate 4. The positive electrode plate 4 has areas where a positive electrode active material layer 4a is formed on both sides of the positive electrode core. A plurality of positive electrode connectors 4b are provided at one end in the width direction of the positive electrode plate 4. The positive electrode connector 4b is composed of an exposed portion of the positive electrode core. A positive electrode protective layer 4c having a lower conductivity than the positive electrode active material layer 4a is provided at the root of the positive electrode connector 4b. As the positive electrode protective layer 4c, it can be set as an insulating layer made of resin, a layer containing ceramics and a resin binder, etc. In addition, the positive electrode protective layer 4c can contain a conductive material such as a carbon material. It should be noted that the positive electrode protective layer 4c may not be provided.

[0135] [Negative plate]

[0136] Next, a method for manufacturing the negative electrode plate will be described.

[0137] [Preparation of Negative Electrode Active Material Layer Slurry]

[0138] Graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as a binder, and water as a dispersion medium were kneaded so that the mass ratio of graphite:SBR:CMC was 98:1:1 to prepare a negative electrode active material layer slurry.

[0139] [Formation of Negative Electrode Active Material Layer]

[0140] The negative electrode active material layer slurry prepared by the above method was applied to both surfaces of a copper foil having a thickness of 8 μm as a negative electrode core by a die coater.

[0141] The negative electrode core coated with the negative electrode active material layer slurry is dried to remove the water contained in the negative electrode active material layer slurry. Thus, the negative electrode active material layer is formed. Thereafter, the negative electrode active material layer is compressed into a negative electrode original plate. The negative electrode original plate is cut into a predetermined shape to serve as a negative electrode plate 5. It should be noted that the cutting of the negative electrode original plate can be performed by irradiating energy rays such as laser, a mold or a cutter, etc.

[0142] Figure 5 : is a top view of the negative electrode plate 5. The negative electrode plate 5 has regions where negative active material layers 5a are formed on both sides of the negative electrode core. A plurality of negative electrode tabs 5b are provided at one end in the width direction of the negative electrode plate 5. The negative electrode tabs 5b are formed by the exposed portion of the negative electrode core.

[0143] [Production of electrode body]

[0144] The strip-shaped positive electrode plate 4 and the strip-shaped negative electrode plate 5 produced by the above method are wound with a strip-shaped separator made of polyolefin to produce a flat wound electrode body 3. The electrode body 3 has a flat region in the center and curved portions at both ends of the flat region. One outer surface of the flat region is the first main surface 3a, and the other outer surface of the flat region is the second main surface 3b.

[0145] Figure 6 : is a top view of the electrode body 3. A positive electrode terminal assembly 40 having a plurality of positive electrode terminals 4b stacked is provided at one end in the direction in which the winding axis of the electrode body 3 extends. A negative electrode terminal assembly 50 having a plurality of negative electrode terminals 5b stacked is provided at the other end in the direction in which the winding axis of the electrode body 3 extends. It should be noted that in a direction perpendicular to the direction in which the winding axis of the electrode body 3 extends and in a direction perpendicular to the thickness direction of the electrode body 3 ( Figure 6 In the vertical direction in the winding direction), the center of the positive electrode terminal assembly 40 and the center of the negative electrode terminal assembly 50 are from one side of the winding axis ( Figure 6 The upper side of the offset configuration.

[0146] It should be noted that the shape of the positive electrode terminal 4b and / or the negative electrode terminal 5b when viewed from above can be set to a shape in which the width gradually increases from the front end to the root. If it is configured in this way, the positive electrode terminal 4b and / or the negative electrode terminal 5b will not be easily damaged even when the secondary battery 20 is subjected to impact or vibration. In addition, it is more effective to set the corner of the root to an R shape. It should be noted that by providing the positive electrode protective layer 4c at the root of the positive electrode terminal 4b in the above manner, the damage to the positive electrode terminal 4b can be suppressed. In addition, by providing the negative electrode active material layer 5a at the root of the negative electrode terminal 5b, the damage to the negative electrode terminal 5b can be suppressed.

[0147] [Second Positive Electrode Current Collector and Second Negative Electrode Current Collector]

[0148] Fig. 7A It is a plan view of the second positive electrode current collector 62 . Figure 7B It is along Fig. 7A VIIB-VIIB line in FIG. The second positive electrode collector 62 has a second region connection portion 62a, an inclined portion 62b, and a joint connection portion 62c. The second region connection portion 62a is connected to the second region 61b of the first positive electrode collector 61. The positive electrode joint group 40 is connected to the joint connection portion 62c. The inclined portion 62b is inclined relative to the second region connection portion 62a and the joint connection portion 62c, respectively, to connect the second region connection portion 62a and the joint connection portion 62c. A height difference is formed between the second region connection portion 62a and the joint connection portion 62c by the inclined portion 62b. It should be noted that the angle of the inclined portion 62b relative to the second region connection portion 62a and the angle of the inclined portion 62b relative to the joint connection portion 62c are not particularly limited. It should be noted that the shape of the second positive electrode collector 62 is not limited. The second positive electrode collector 62 can also be set to a flat plate shape.

[0149] The second region connecting portion 62a is provided with a recessed portion 62d. The portion provided with the recessed portion 62d is thinner than the surrounding portion. A through hole 62e is provided inside the recessed portion 62d. Inside the recessed portion 62d, the second region 61b is joined to the second region connecting portion 62a.

[0150] The second region connecting portion 62a is provided with a fuse portion 62f. The fuse portion 62f is a portion that is fused when an excess current flows through the secondary battery 20. The fuse portion 62f is a portion whose cross-sectional area is reduced by forming a fuse hole 62g in the second region connecting portion 62a. The fuse portion 62f is preferably provided between a position where the second region 61b is joined and a position where the positive electrode tab assembly 40 is joined in the second positive electrode current collector 62. The fuse portion 62f may be a portion where the cross-sectional area is reduced, or may be a portion where a notch or a thin-walled portion is provided.

[0151] The second negative electrode collector 72 may have the same shape as the second positive electrode collector 62. The second positive electrode collector 62 is preferably made of metal, more preferably aluminum. The second negative electrode collector 72 is preferably made of metal, more preferably copper, nickel or iron.

[0152] The second positive electrode current collector 62 does not need to have the fuse 62 f. Also, the second negative electrode current collector 72 does not need to have the fuse.

[0153] [Connection between the first current collector and the connector assembly]

[0154] like Figure 8As shown, the positive electrode tab assembly 40 is arranged on the tab connection portion 62c of the second positive electrode current collector 62, and the tab connection portion 62c is joined to the positive electrode tab assembly 40 to form a joint portion 63. For joining, ultrasonic welding (ultrasonic joining), resistance welding, welding based on high energy beams such as laser irradiation, etc. can be used. The tab connection portion 72c of the second negative electrode current collector 72 and the negative electrode tab assembly 50 can also be joined using the same method.

[0155] Preferably, the joint portion 63 is located at the tab connection portion 62c of the second positive electrode current collector 62 in the width direction ( Figure 8 In the left and right direction), toward the root side of the positive electrode terminal group 40 ( Figure 8 With such a configuration, when the positive electrode tab assembly 40 is bent, a curved shape can be stably formed near the root of the positive electrode tab assembly 40 more reliably. Thus, damage to the positive electrode tab assembly 40 can be suppressed. In addition, even if the positive electrode tab 4b is displaced, the positive electrode tab assembly 40 can be stably joined to the tab connection portion 62c.

[0156] like Figure 8 As shown, it is preferred that the front end of the positive electrode tab assembly 40 extends from the tab connection portion 62c of the second positive electrode current collector 62 to the outside ( Figure 8 In the state where the positive electrode tab assembly 40 is protruding (left side in the middle), the positive electrode tab assembly 40 is joined to the tab connection portion 62c. Thereby, the positive electrode tab assembly 40 and the tab connection portion 62c can be joined more stably.

[0157] Fig. 9 : is a perspective view of the electrode body 3 to which the second positive electrode collector 62 and the second negative electrode collector 72 are mounted. The lower end portion of the second positive electrode collector 62 (the portion that becomes the end portion on the bottom 1a side of the square outer package 1) is preferably located below the lower end portion of the positive electrode tab group 40 (the portion that becomes the end portion on the bottom 1a side of the square outer package 1). If it is such a structure, in the process of bending the positive electrode tab group 40 described later, the positive electrode tab group 40 can be bent more reliably and stably. It should be noted that the same is true for the second negative electrode collector 72 and the negative electrode tab group 50.

[0158] [Bending of the joint assembly]

[0159] like Fig.10 As shown in FIG. 1 , the positive electrode tab assembly 40 is bent. Fig. 9As shown, the tab connection portion 62c of the second positive electrode current collector 62 arranged substantially parallel to the first main surface 3a and the second main surface 3b of the electrode body 3 is bent so as to be in a state substantially perpendicular to the winding axis of the electrode body 3 (for example, the inclination of the tab connection portion 62c relative to the winding axis is less than ±15°) by bending the positive electrode tab group 40. In addition, the tape 80 as a fixing member is attached in a manner spanning the first main surface 3a of the electrode body 3-the tab connection portion 62c-the second main surface 3b of the electrode body 3. With such a configuration, the bent state of the positive electrode tab group 40 can be maintained more stably. In addition, the bent positive electrode tab group 40 can be made elastic, and when the second positive electrode current collector 62 is pressed toward the electrode body 3 side, the second positive electrode current collector 62 can move in a direction close to the electrode body 3. It should be noted that when the positive electrode tab group 40 is bent, the second positive electrode current collector 62 itself is not bent.

[0160] like Fig.10 As shown, the positive terminal assembly 40 has a contact area 40b that contacts the terminal connection portion 62c, a root area 40a that is arranged on the root side of the positive terminal assembly 40 compared to the contact area 40b, and a front end area 40c that is arranged on the front end side of the positive terminal assembly 40 compared to the contact area 40b. The front end area 40c is fixed with a tape 80 in a state where it is bent from the contact area 40b, thereby improving the assembly performance in the subsequent process. It should be noted that by providing the front end area 40c, the contact area 40b can be widely provided, and when the positive terminal assembly 40 is joined to the terminal connection portion 62c, it can be joined more stably. It should be noted that the front end area 40c may not be provided.

[0161] It should be noted that the negative electrode tab assembly 50 is also fixed in a bent state similarly to the positive electrode tab assembly 40 .

[0162] [Electrode body group]

[0163] The electrode assembly 300 is manufactured by stacking a plurality of electrode assemblies 3 in a state where the positive electrode tab assembly 40 and the negative electrode tab assembly 50 are respectively folded, and wrapping and fixing them with an electrode assembly fixing member 90 such as a tape. Fig.11 3D is a perspective view of an electrode assembly 300. Each positive electrode connector assembly 40 is arranged on the same side, and each negative electrode connector assembly 50 is arranged on the same side. In addition, in each electrode assembly 3, the positive electrode connector assembly 40 is bent in the same direction. In each electrode assembly 3, the negative electrode connector assembly 50 is bent in the same direction. The electrode assembly 300 involved in the embodiment includes two electrode assemblies 3. It should be noted that the number of electrode assemblies 3 included in the electrode assembly 300 is not limited to two.

[0164] The adhesive tape 80 as a fixing member attached across the first main surface 3a of the electrode body 3, the joint connecting portion 62c, and the second main surface 3b of the electrode body 3 preferably includes a first adhesive tape 80a and a second adhesive tape 80b. Fig.11 As shown, it is preferred that the first tape 80a is attached to the tab connection portion 62c of the second positive electrode current collector 62 above the junction 63 between the tab connection portion 62c and the positive electrode tab assembly 40, and the second tape 80b is attached below the junction 63 between the tab connection portion 62c and the positive electrode tab assembly 40. With such a configuration, the bending state of the positive electrode tab assembly 40 can be stably maintained. It should be noted that the same is true for the tab connection portion 72c of the second negative electrode current collector 72.

[0165] like Fig.11 As shown, it is preferred that the upper end of the first tape 80a disposed on the upper side is disposed above the upper end of the positive electrode tab assembly 40, and the lower end of the second tape 80b disposed on the lower side is disposed below the lower end of the positive electrode tab assembly 40. With such a configuration, the curved shape of the positive electrode tab assembly 40 can be more reliably maintained.

[0166] like Fig.11 As shown, in the stacking direction of the electrode bodies 3, the second positive electrode collectors 62 mounted on the electrode bodies 3 are arranged at intervals and connected to the second regions 61b of the first positive electrode collectors 61. The same is true for the second negative electrode collectors 72.

[0167] In the electrode body 3 according to the embodiment, the joint 63 of the positive electrode tab group 40 and the tab connecting portion 62 c is arranged between the lower end of the first tape 80 a and the upper end of the second tape 80 b .

[0168] It should be noted that, in the embodiment, the two tapes, the first tape 80a and the second tape 80b, may be one tape. In this case, it is preferred that the upper end of one tape is arranged above the upper end of the positive electrode joint group 40, and the lower end of one tape is arranged below the lower end of the positive electrode joint group 40. The tape 80 may cover the portion of the joint connection portion 62c where the joint portion 63 is formed. The second negative electrode current collector 72 and the negative electrode joint group 50 side may also be arranged in the same configuration.

[0169] [Connection between the first current collector and the second current collector]

[0170] The second region 61b of the first positive electrode collector 61 is arranged inside the second region connecting portion 62a of the second positive electrode collector 62, and the second region 71b of the first negative electrode collector 71 is arranged inside the second region connecting portion 72a of the second negative electrode collector 72. Furthermore, the second region 61b of the first positive electrode collector 61 is connected to the second region connecting portion 62a of the second positive electrode collector 62. In addition, the second region 71b of the first negative electrode collector 71 is joined to the second region connecting portion 72a of the second negative electrode collector 72. As a joining method, ultrasonic welding (ultrasonic joining), resistance welding, welding based on high energy beams such as laser irradiation, etc. can be used. It is particularly preferable to use welding based on high energy beams such as laser irradiation.

[0171] Figures 12A to 12C The diagram is a cross-sectional view of the second region 61b of the first positive electrode collector 61, the second region 71b of the first negative electrode collector 71, the second region connecting portion 62a of the second positive electrode collector 62, and the second region connecting portion 72a of the second negative electrode collector 72 at each stage along the winding axis of the electrode body 3.

[0172] like Fig. 12A As shown, the second region 61b of the first positive current collector 61 and the second region 71b of the first negative current collector 71 are arranged between the second region connecting portion 62a of the second positive current collector 62 and the second region connecting portion 72a of the second negative current collector 72. At this time, the distance D1 between the inner surface of the second region connecting portion 62a and the inner surface of the second region connecting portion 72a is preferably greater than the distance D2 between the outer surface of the second region 61b and the outer surface of the second region 71b. It should be noted that D1 is preferably larger than D2 by 0.1 to 5 mm, and more preferably larger by 0.2 to 3 mm.

[0173] Then, if Fig. 12B As shown in FIG. 1 , the second region connecting portion 62a and / or the second region connecting portion 72a are changed in position on the inner side so that the distance between the second region connecting portion 62a and the second region connecting portion 72a becomes smaller. Thus, the distance D1 between the inner surface of the second region connecting portion 62a and the inner surface of the second region connecting portion 72a is changed to D1′. At this time, the difference between D2 and D1′ is preferably 0 to 0.2 mm.

[0174] exist Fig. 12B In the state shown, the second region connecting portion 62a and the second region connecting portion 72a are irradiated with high energy lines such as laser, so that the second region 61b of the first positive electrode collector 61 and the second region connecting portion 62a of the second positive electrode collector 62 are joined by welding, and the second region 71b of the first negative electrode collector 71 and the second region connecting portion 72a of the second negative electrode collector 72 are joined by welding.

[0175] like Fig. 12C As shown, the joint 64, which is the welded portion between the second region 61b and the second region connecting portion 62a, is formed in the recess 62d. Also, the joint 74, which is the welded portion between the second region 71b and the second region connecting portion 72a, is formed in the recess 72d.

[0176] By setting Figures 12A to 12C By welding the first positive electrode collector 61 and the second positive electrode collector 62, and the first negative electrode collector 71 and the second negative electrode collector 72 in a simpler method, the first positive electrode collector 61 and the second positive electrode collector 62, and the first negative electrode collector 71 and the second negative electrode collector 72 can be welded more stably. Thus, the highly reliable joints 64 and 74 can be formed.

[0177] The portion where the recess 62d and the recess 72d are formed is a portion that is thinner than the surrounding portion. By welding in a manner that the joint 64 and the joint 74 are formed in the thin portion, a joint with higher quality can be formed more stably. Thus, a secondary battery with higher reliability is achieved. In addition, by using the through hole 62e to determine whether there is a gap or the size of the gap between the second region 61b and the second region connecting portion 62a, the second region 61b and the second region connecting portion 62a can be more stably joined by welding. It should be noted that the same is true for the through hole 72e.

[0178] Fig.13 It is a perspective view showing a state where the first positive electrode collector 61 and the second positive electrode collector 62 , and the first negative electrode collector 71 and the second negative electrode collector 72 are connected, respectively.

[0179] [Electrode body holder]

[0180] Fig.14 It is a development view of the electrode body holder 14 . Fig.14 The insulating sheet constituting the electrode body holder 14 is bent at the dotted line portion to form a box-shaped electrode body holder 14. The electrode body holder 14 has a holder bottom 14a, a holder first main surface 14b, a holder second main surface 14c, a holder first side surface 14d, a holder second side surface 14e, a holder third side surface 14f, a holder fourth side surface 14g, a holder fifth side surface 14h, and a holder sixth side surface 14i.

[0181] When the electrode body holder 14 is formed into a box shape, the holder first side surface 14d, the holder second side surface 14e, and the holder third side surface 14f have overlapping regions, and the holder fourth side surface 14g, the holder fifth side surface 14h, and the holder sixth side surface 14i have overlapping regions.

[0182] The electrode assembly 300 is inserted into the square outer package 1 while the electrode assembly 300 is arranged in the box-shaped electrode assembly holder 14. The sealing plate 2 is joined to the square outer package 1, and the opening of the square outer package 1 is sealed by the sealing plate 2. The electrolyte is injected from the electrolyte injection hole 15 provided in the sealing plate 2, and the electrolyte injection hole 15 is sealed by the sealing member 16. Thus, the secondary battery 20 is obtained.

[0183] [Secondary battery]

[0184] In the secondary battery 20 involved in the embodiment, the positive electrode collector 6 is formed to include a first positive electrode collector 61 and a second positive electrode collector 62. If it is such a structure, when the positive electrode tab group 40 is bent, the positive electrode collector 6 can be bent without bending the positive electrode tab group 40, and a secondary battery with high volume energy density can be made more stably using a simpler method. It should be noted that it is more effective when the number of electrode bodies 3 accommodated in the battery shell 100 is more than 2. According to the present invention, the degree of freedom of the number of electrode bodies 3 accommodated in the battery shell 100 is improved. According to the present invention, when the number of electrode bodies 3 accommodated in the battery shell 100 is more than 2, the positive electrode collector 6 can also be made into a complex shape and a secondary battery with high reliability can be stably manufactured. The present invention is particularly effective when the number of electrode bodies 3 accommodated in the battery shell 100 is more than 2 and is an odd number.

[0185] In the secondary battery 20, the tab connection portion 62c of the second positive electrode current collector 62 is arranged on the first side wall 1b side of the square outer package 1 compared to the second region connection portion 62a of the second positive electrode current collector 62. With such a configuration, the space between the first side wall 1b and the electrode body 3 can be more effectively utilized, so that the power generation portion of the electrode body 3 can be made larger, resulting in a secondary battery with a higher volume energy density. It should be noted that the same is true for the second negative electrode current collector 72.

[0186] It is preferred that the positive electrode tab group 40 is offset toward the sealing plate 2 in the electrode body 3. Thus, the conductive path from the positive electrode tab group 40 to the positive terminal 8 can be shortened to form a secondary battery 20 with a low internal resistance. It is preferred that the negative electrode tab group 50 is offset toward the sealing plate 2 in the electrode body 3. Thus, the conductive path from the negative electrode tab group 50 to the negative terminal 9 can be shortened to form a secondary battery 20 with a low internal resistance.

[0187] It is preferable to arrange an insulating member (not shown) different from the electrode body holder 14 between the overlapping region of the second region 61b of the first positive electrode collector 61 and the second region connecting portion 62a of the second positive electrode collector 62 and the first side wall 1b of the square outer package 1. In addition, it is preferable to arrange an insulating member (not shown) different from the electrode body holder 14 between the overlapping region of the second region 71b of the first negative electrode collector 71 and the second region connecting portion 72a of the second negative electrode collector 72 and the first side wall 1c of the square outer package 1. With such a configuration, even when the secondary battery 20 is subjected to impact or vibration, damage to the joint between the components, the positive electrode connector assembly 40 or the negative electrode connector assembly 50 can be suppressed.

[0188] Fig.15 2 is a cross-sectional view of the vicinity of the joint 63 of the second positive electrode current collector 62 and the positive electrode tab assembly 40 in another embodiment, and is a view showing a state where the positive electrode tab assembly 40 is bent and fixed. Fig.15 As shown, the portion where the joint 63 is formed in the tab connection portion 62c of the second positive electrode current collector 62 can be covered with the tape 80. Even if there are burrs or metal powder generated when the joint 63 is formed in the portion where the joint 63 is formed in the tab connection portion 62c of the second positive electrode current collector 62, the tape 80 can be used to suppress the movement of the burrs or metal powder.

[0189] In addition, if Fig.15 As shown, the portion of the positive electrode tab assembly 40 where the joint 63 is formed can be covered with the tape 81. Even if there are burrs or metal powder generated when the joint 63 is formed in the portion of the positive electrode tab assembly 40, the tape 81 can suppress the movement of the burrs or metal powder. The tape 81 is preferably attached before the positive electrode tab assembly 40 is bent.

[0190] It should be noted that the adhesive material can be applied or attached to the portion of the joint portion 63 formed in the tab connection portion 62c of the second positive electrode current collector 62 and / or the portion of the joint portion 63 formed in the positive electrode tab assembly 40. In addition, the portion of the joint portion 63 formed in the tab connection portion 62c of the second positive electrode current collector 62 and / or the portion of the joint portion 63 formed in the positive electrode tab assembly 40 can be covered with a hot melt resin. In addition, the tab connection portion 72c of the second negative electrode current collector 72 and the negative electrode tab assembly 50 can also be set to the same structure.

[0191] In the secondary battery 20 involved in the above-mentioned embodiment, a second positive electrode collector 62 and a second negative electrode collector 72 are installed on one electrode body 3. However, it is not limited to this. Multiple second positive electrode collectors and / or multiple second negative electrode collectors can be installed on one electrode body 3. Other embodiments of installing multiple second positive electrode collectors on one electrode body 3 are described below. It should be noted that multiple second negative electrode collectors can be installed on one electrode body 3 using the same method. In other embodiments, the description of the parts common to the secondary battery 20 of the above-mentioned embodiment is omitted.

[0192] like Fig.16 As shown, the positive electrode connector group 40 is divided into two bundles, and the connector connection portion 162c of the second positive electrode collector 162 is connected by welding to one bundle of positive electrode connector groups 40A and the other bundle of positive electrode connector groups 40B, respectively, to form a joint portion 163. Preferably, one bundle of positive electrode connector groups 40A is concentrated on the first main surface 3a side, and the other bundle of positive electrode connector groups 40B is concentrated on the second main surface 3b side. It should be noted that the second positive electrode collector 162 can be set to the same structure as the second positive electrode collector 62 involved in the above embodiment.

[0193] like Fig.17 As shown, the positive electrode connector group 40A bundled on the side of the first main surface 3a is bent toward the center side in the thickness direction of the electrode body 3, and the positive electrode connector group 40B bundled on the side of the second main surface 3b is bent toward the center side in the thickness direction of the electrode body 3. In this state, it is fixed by the tape 80 serving as a fixing component.

[0194] like Fig.18 As shown, the second positive electrode collector 162 connected to the positive electrode tab group 40A of one electrode body 3 and the second positive electrode collector 162 connected to the positive electrode tab group 40B are connected to the first positive electrode collector 61 by welding. The second positive electrode collector 162 has a second region connecting portion 162a, an inclined portion 162b and a tab connecting portion 162c. The second region connecting portion 162a is connected to the second region 61b of the first positive electrode collector 61. It should be noted that the configuration in other embodiments is particularly effective when the thickness of one of the electrode bodies 3 becomes large.

[0195] <Others>

[0196] In the above embodiment, the electrode body is an example of a wound type electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, but the present invention is not limited thereto and may be a stacked type electrode body including a plurality of positive electrode plates and a plurality of negative electrode plates.

[0197] In the above embodiment, an example of manufacturing a wound electrode body by winding a positive electrode plate having a plurality of positive electrode tabs and a negative electrode plate having a plurality of negative electrode tabs is shown, but the present invention is not limited thereto. A positive electrode tab group or a negative electrode tab group may also be formed by cutting off the exposed portion of the positive electrode core body or the exposed portion of the negative electrode core body wound in the wound electrode body.

[0198] In the above embodiment, an example is shown in which the positive electrode current collector 6 and the negative electrode current collector 7 are each composed of two members, but the positive electrode current collector 6 and the negative electrode current collector 7 may each be composed of one member.

[0199] As for the positive electrode plate, the negative electrode plate, the separator, the electrolyte, and the like, known materials can be used.

[0200] The aluminum mentioned above includes aluminum and aluminum alloys mainly composed of aluminum. The copper mentioned above includes copper and copper alloys mainly composed of copper. The iron mentioned above includes iron alloys mainly composed of iron. The nickel mentioned above includes nickel alloys mainly composed of nickel.

[0201] The adhesive tape preferably has a base material and an adhesive layer formed on the base material. The base material is preferably made of polyethylene, polypropylene, polyester, nylon, vinyl chloride, Teflon (registered trademark), polyimide, Kapton (registered trademark), polyphenylene sulfide or polyethylene naphthalate. The material of the adhesive layer is preferably made of acrylic adhesive, silicone adhesive, rubber adhesive, etc. However, it is not limited to these materials. It should be noted that the adhesive layer preferably has adhesiveness at room temperature.

[0202] As an embodiment, an example in which the fixing member is an adhesive tape is shown, but the invention is not limited thereto. As the fixing member, a resin frame, a metal frame, a ceramic frame, a clip-shaped member, etc. can be considered. It should be noted that as the fixing member, an adhesive tape is more preferred.

[0203] A pressure-sensitive current-blocking device can be provided on the conductive path between the positive electrode connector group and the positive electrode terminal, or the conductive path between the negative electrode connector group and the negative electrode terminal. The current-blocking device is a device that operates when the pressure in the battery case becomes greater than a specified value, cuts off the conductive path between the positive electrode connector group and the positive electrode terminal, or the conductive path between the negative electrode connector group and the negative electrode terminal, and blocks the flow of current.

[0204] Description of Reference Numerals

[0205] 20 Secondary batteries

[0206] 100 Battery Case

[0207] 1 Square outer packaging

[0208] 1a Bottom

[0209] 1b, 1c First side wall

[0210] 1d, 1e Second side wall

[0211] 2 Sealing plate

[0212] 3 Electrode body

[0213] 3a 1st main surface

[0214] 3b Second main surface

[0215] 300 Electrode assembly

[0216] 4 Positive plate

[0217] 4a Positive electrode active material layer

[0218] 4b Positive terminal

[0219] 4c Positive electrode protection layer

[0220] 40 Positive terminal set

[0221] 40a Root zone

[0222] 40b Abutment area

[0223] 40c front area

[0224] 5 Negative plate

[0225] 5a Negative electrode active material layer

[0226] 5b Negative terminal

[0227] 50 Negative terminal set

[0228] 6. Positive electrode collector

[0229] 61 1st positive electrode current collector

[0230] 61a Area 1

[0231] 61b Area 2

[0232] 61c Notch

[0233] 62 Second positive electrode current collector

[0234] 62a Second area connection portion

[0235] 62b Inclined portion

[0236] 62c Connector connection

[0237] 62d recess

[0238] 62e Through hole

[0239] 62f Fuse

[0240] 62g Fuse Hole

[0241] 63, 64 joint

[0242] 7 Negative electrode collector

[0243] 71 First negative electrode current collector

[0244] 71a Area 1

[0245] 71b Area 2

[0246] 71c Notch

[0247] 72 Second negative electrode current collector

[0248] 72a Second area connection portion

[0249] 72b Inclined portion

[0250] 72c Connector connection

[0251] 72d concavity

[0252] 72e Through hole

[0253] 74 Joint

[0254] 8 Positive terminal

[0255] 9 Negative terminal

[0256] 10, 12 External insulation parts

[0257] 11, 13 Internal insulation parts

[0258] 14 Electrode body support

[0259] 14a Bracket bottom

[0260] 14b Bracket first main surface

[0261] 14c Bracket second main surface

[0262] 14d Bracket first side

[0263] 14e Bracket 2nd side

[0264] 14f Bracket third side

[0265] 14g Bracket 4th side

[0266] 14h Bracket side 5

[0267] 14i Bracket side 6

[0268] 15 Electrolyte filling hole

[0269] 16 Sealing parts

[0270] 17 Gas exhaust valve

[0271] 80 Tape

[0272] 80a 1st tape

[0273] 80b Second tape

[0274] 81 Tape

[0275] 90 Electrode body fixing parts

[0276] 40A, 40B positive terminal set

[0277] 162 Second positive electrode current collector

[0278] 162a Second area connection part

[0279] 162b Inclined portion

[0280] 162c Connector connection

[0281] 163 Joint

Claims

1. A secondary battery comprising: An electrode body including a positive electrode plate and a negative electrode plate, A square outer packaging body having an opening and accommodating the electrode body, The sealing plate for sealing the opening, and The terminal is mounted on the sealing plate, In the first direction, the electrode body has a positive electrode tab group at one end and a negative electrode tab group at the other end. The square outer packaging body has a bottom, a pair of first side walls arranged in directions opposite to each other, and a pair of second side walls arranged in directions opposite to each other. The positive electrode connector group or the negative electrode connector group is electrically connected to the terminal via a first current collector and a second current collector. The first current collector includes a first region disposed between the sealing plate and the electrode body, and a second region bent from an end of the first region and disposed between the first side wall on one side and the electrode body. The second current collector includes a tab connection portion and a second region connection portion, The joint connection portion and the second region connection portion are formed so as to be aligned in a second direction, the second direction being orthogonal to the first direction and parallel to the thickness direction of the sealing plate, The positive electrode tab group or the negative electrode tab group is connected to the tab connection portion of the second current collector at a joint portion in a bent state. The second region connection portion does not overlap with the positive electrode tab group or the negative electrode tab group in the first direction, The second current collector is welded to the second region at the second region connecting portion so as to overlap with the second region in the first direction.

2. The secondary battery according to claim 1, It comprises a plurality of the electrode bodies, The plurality of second current collectors connected to the respective positive electrode tab groups or the negative electrode tab groups of the plurality of electrode bodies are welded to the second region of the first current collector.

3. The secondary battery according to claim 1 or 2, wherein: The positive electrode terminal group or the negative electrode terminal group provided in one electrode body is divided into a plurality of groups, The second current collectors are provided to be connected to the plurality of positive electrode tab groups or the plurality of negative electrode tab groups, respectively. The plurality of second current collectors are welded to the second region of the first current collector.

4. The secondary battery according to claim 1 or 2, wherein: The second current collector includes a second region connecting portion and a tab connecting portion, The second region connecting portion is welded to the second region, The positive electrode connector group or the negative electrode connector group is connected to the connector connection portion. A distance between the first side wall on one side and the joint connecting portion is smaller than a distance between the first side wall on one side and the second region connecting portion.

5. The secondary battery according to claim 1 or 2, wherein: The second current collector is provided with a recessed portion, A through hole is provided inside the recessed portion. The second current collector is welded to the second region inside the recess.

6. The secondary battery according to claim 1 or 2, wherein: The second current collector has a plate-shaped region arranged along one side of the first side wall. The positive electrode tab group or the negative electrode tab group is connected to a surface of the plate-shaped region that is located on the electrode body side.

7. The secondary battery according to claim 1 or 2, wherein: Notches are provided at both ends of the second region in the width direction.

8. The secondary battery according to claim 1 or 2, wherein: The second current collector is provided with a fuse portion between a welded portion between the second current collector and the second region and a joined portion between the second current collector and the positive electrode tab group or the negative electrode tab group.

9. The secondary battery according to claim 1 or 2, wherein: At least one of the positive electrode tab group and the negative electrode tab group is provided at a position offset toward the sealing plate in the electrode body.

10. A method for manufacturing a secondary battery, which is the following method for manufacturing a secondary battery, wherein the secondary battery comprises: An electrode body including a positive electrode plate and a negative electrode plate, A square outer packaging body having an opening and accommodating the electrode body, The sealing plate for sealing the opening, and The terminal is mounted on the sealing plate, In the first direction, the electrode body has a positive electrode tab group at one end and a negative electrode tab group at the other end. The square outer packaging body has a bottom, a pair of first side walls arranged in directions opposite to each other, and a pair of second side walls arranged in directions opposite to each other. The positive electrode connector group or the negative electrode connector group is electrically connected to the terminal via a first current collector and a second current collector. The first current collector includes a first region and a second region, The second current collector includes a tab connection portion and a second region connection portion, The joint connection portion and the second region connection portion are formed so as to be aligned in a second direction, the second direction being orthogonal to the first direction and parallel to the thickness direction of the sealing plate, The second region connection portion does not overlap with the positive electrode tab group or the negative electrode tab group in the first direction, The manufacturing method of the secondary battery comprises the following steps: a step of attaching the first current collector to the sealing plate in the first region; A step of connecting the positive electrode tab assembly or the negative electrode tab assembly to the tab connection portion of the second current collector at a junction; a step of bending the positive electrode tab group or the negative electrode tab group and changing the direction of the second current collector connected to the positive electrode tab group or the negative electrode tab group; and The step of welding the second region connecting portion of the second current collector connected to the positive electrode tab group or the negative electrode tab group to the second region of the first current collector attached to the sealing plate so as to overlap with the second region in the first direction.

11. The method for manufacturing a secondary battery according to claim 10, wherein: The first current collector includes a first region disposed between the sealing plate and the electrode body, and a second region bent from an end of the first region and disposed between the first side wall on one side and the electrode body. The second current collector to which the positive electrode tab group or the negative electrode tab group is connected is welded to the second region.

12. The method for manufacturing a secondary battery according to claim 11, wherein: The second current collector is provided with a recessed portion, A through hole is provided in the recess, The second current collector is welded in the second region by irradiating the recess with high energy rays.

13. The method for manufacturing a secondary battery according to claim 11 or 12, wherein: Notches are provided at both ends of the second region in the width direction. The second current collector is welded to the second region while holding the notch portion.

14. The method for manufacturing a secondary battery according to claim 11 or 12, wherein: The terminal is a negative terminal, The first current collector is a first negative electrode current collector, The first region is a negative electrode first region, The second region is a negative electrode second region, The second current collector is a second negative electrode current collector, further comprising a first positive electrode current collector and a second positive electrode current collector, The first positive electrode current collector includes: a positive electrode first region disposed between the sealing plate and the electrode body, and a positive electrode second region disposed between the other first side wall and the electrode body. The manufacturing method of the secondary battery has the following steps: The step of mounting the first positive electrode current collector on the sealing plate; A step of connecting the positive electrode tab assembly to the second positive electrode current collector; The step of bending the positive electrode tab assembly and changing the direction of the second positive electrode current collector connected to the positive electrode tab assembly; The step of disposing the positive electrode second region of the first positive electrode collector mounted on the sealing plate and the negative electrode second region of the first negative electrode collector mounted on the sealing plate between the second positive electrode collector connected to the positive electrode tab group and the second negative electrode collector connected to the negative electrode tab group; a step of reducing the distance between the second positive electrode current collector and the second negative electrode current collector; and The step of welding the positive electrode second region to the second positive electrode current collector and welding the negative electrode second region to the second negative electrode current collector.

Images