Battery and method for manufacturing the same

Abstract

This invention provides a battery capable of effectively preventing foreign matter from intruding into the electrode body. The battery of this invention includes: an electrode body, which is formed by stacking a positive electrode plate and a negative electrode plate separated by a separator; an outer casing having an opening for housing the electrode body; a sealing plate for closing the opening; and a positive terminal and a negative terminal mounted on the sealing plate. The sealing plate has an injection hole for injecting electrolyte. One of the surfaces of the electrode body parallel to the stacking direction of the positive and negative electrode plates faces the sealing plate. The positive electrode plate is disposed in a manner that protrudes from one surface onto the sealing plate. The positive electrode tab on one side is electrically connected to the positive terminal via a positive current collector disposed between the electrode body and the sealing plate. The negative electrode tab on one side of the negative electrode plate, which protrudes from one side, is electrically connected to the negative terminal via a negative current collector disposed between the electrode body and the sealing plate. The positive electrode tab and the positive current collector are welded together, and the negative electrode tab and the negative current collector are welded together. An electrically insulating porous body is disposed between one side and the positive current collector and between one side and the negative current collector.

Description

Technical Field

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

[0002] Batteries such as alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used in stationary battery systems for suppressing output fluctuations of driving power supplies for electric vehicles (EVs), hybrid electric vehicles (HEVs, PHEVs), solar power generation, wind power generation, etc., and for peak shifting of system power for storing electricity at night and using it during the day.

[0003] For the above-mentioned battery, foreign matter is sometimes mixed in during its assembly process, especially if the mixed foreign matter is a metal foreign matter, it may cause an internal short circuit. The mechanism of internal short circuit is as follows. First, when the metal foreign matter adheres to the positive electrode material, the metal foreign matter is dissolved into metal ions in the electrolyte due to the higher potential of the positive electrode, and the metal ions are precipitated as metal when they reach the negative electrode. Then, the metal is precipitated in a manner that grows toward the positive electrode, and when the metal penetrates the diaphragm and contacts the positive electrode, an internal short circuit is caused.

[0004] In order to prevent foreign matter such as metal foreign matter from entering the battery, the secondary battery is usually assembled in a clean room. In addition, during the assembly process, foreign metal matter attached to the electrode body is removed by blowing, suction, magnetic attraction, wiping with a polishing tape, etc.

[0005] Patent Document 1 proposes a sealed battery in which an electrode body is inserted into a bag-shaped porous body, and the porous body with the inserted electrode body is inserted into a sealed container.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2009-87812 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] However, in the method described in Patent Document 1, the method and advantages of disposing a porous body between the electrode body and the lid of the sealed container are not specifically described, and the specific method is unknown.

[0011] The present invention has been made in view of the above-mentioned situation, and an object of the present invention is to provide a battery capable of effectively suppressing the intrusion of foreign matter into an electrode body.

[0012] Solutions for solving problems

[0013] The battery of the present invention has the following structure, which includes: an electrode body, which is formed by stacking a positive electrode plate and a negative electrode plate with a separator; an outer body, which has an opening, and the outer body accommodates the electrode body; a sealing plate, which seals the opening; and a positive electrode external terminal and a negative electrode external terminal, the positive electrode external terminal and the negative electrode external terminal are mounted on the sealing plate, and the sealing plate is provided with an injection hole for injecting electrolyte into the outer body, one of the surfaces of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate is opposite to the sealing plate, and the positive electrode plate is protruding from the one surface The positive electrode tab arranged on the one surface side is electrically connected to the positive electrode external terminal by means of the positive electrode collector arranged between the electrode body and the sealing plate, and the negative electrode tab of the negative electrode plate arranged on the one surface side in a manner protruding from the one surface is electrically connected to the negative electrode external terminal by means of the negative electrode collector arranged between the electrode body and the sealing plate, the positive electrode tab and the positive electrode collector are welded together, the negative electrode tab and the negative electrode collector are welded together, and an electrically insulating porous body is arranged between the one surface and the positive electrode collector and between the one surface and the negative electrode collector.

[0014] The porous body may also be disposed on other surfaces of the electrode body that are parallel to the stacking direction of the positive electrode plate and the negative electrode plate.

[0015] It may also be a structure having the following structure, wherein the electrode body includes: a first electrode body element, which includes the positive electrode plate and the negative electrode plate; and a second electrode body element, which includes the positive electrode plate and the negative electrode plate, the first electrode body element having a first positive electrode tab group including a plurality of the positive electrode tabs and a first negative electrode tab group including a plurality of the negative electrode tabs, the second electrode body element having a second positive electrode tab group including a plurality of the positive electrode tabs and a second negative electrode tab group including a plurality of the negative electrode tabs, the first positive electrode tab group and the second positive electrode tab group are respectively welded to the positive electrode collector, the first negative electrode tab group and the second negative electrode tab group are respectively welded to the negative electrode collector, and the respective porous bodies are respectively arranged on the surface of the first electrode body element constituting the one surface and the surface of the second electrode body element constituting the one surface.

[0016] Furthermore, the first electrode body element and the second electrode body element may have the same structure.

[0017] In addition, the respective porous bodies are porous bodies that are independent of each other and are different members. Therefore, the respective porous bodies may have the same structure.

[0018] An insulating sheet may be disposed between the outer casing and the electrode body.

[0019] The porous body may be formed of a nonwoven fabric.

[0020] In the positive electrode tab and the negative electrode tab, at least a portion of a side end portion protruding from the one surface may be covered with the porous body.

[0021] The manufacturing method of the battery of the present invention includes the following steps: a step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form an electrode body; a step of covering, with an electrically insulating porous body, a surface of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate, at least a surface on which the positive electrode tab and the negative electrode tab are arranged; a step of welding the positive electrode tab to the positive electrode collector and welding the negative electrode tab to the negative electrode collector; a step of electrically connecting the positive electrode collector to the positive electrode external terminal and electrically connecting the negative electrode collector to the negative electrode external terminal; a step of inserting the electrode body into an outer casing having an opening and sealing the opening with a sealing plate; and a step of injecting an electrolyte into the outer casing from an injection hole provided in the sealing plate.

[0022] Another method for manufacturing a battery of the present invention comprises the following steps: a step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form a first electrode body element; a step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form a second electrode body element; a step of covering, with an electrically insulating porous body, a surface of the first electrode body element parallel to the stacking direction of the positive electrode plate and the negative electrode plate, at least the surface on which the positive electrode tab and the negative electrode tab are arranged; a step of stacking the positive electrode plate and the negative electrode plate ...; a step of stacking the positive electrode plate and the negative electrode plate via a separator; a step of stacking the positive electrode plate and the negative electrode plate via a separator; a step of stacking the positive electrode plate and the negative electrode plate via a separator. The present invention relates to a process of covering the surface of the second electrode body element parallel to the stacking direction of the positive electrode plate and the negative electrode plate with a porous body, at least the surface on which the positive electrode tab and the negative electrode tab are arranged; the process of welding the positive electrode tab and the positive electrode collector of the first electrode body element and welding the negative electrode tab and the negative electrode collector; the process of electrically connecting the positive electrode collector and the positive electrode external terminal and electrically connecting the negative electrode collector and the negative electrode external terminal; and the process of integrating the first electrode body element and the second electrode body element into one.

[0023] Effects of the Invention

[0024] The battery of the present invention has a porous body arranged between the surface opposite to the sealing plate and the sealing plate in the surface of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate, so that it can more effectively prevent metal foreign matter generated when the positive electrode tab and the negative electrode tab protruding from the surface are welded to the positive electrode collector and the negative electrode collector from entering the interior of the electrode body from the stacking gap of the surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a perspective view of a secondary battery according to an embodiment.

[0026] Figure 2 yes Figure 1 Cross-sectional view along line II-II.

[0027] Figure 3 It is a top view of the positive plate.

[0028] Figure 4 It is a top view of the negative plate.

[0029] Figure 5 It is a top view of the electrode body according to the embodiment.

[0030] Figure 6 This is a diagram showing a state where the positive electrode tab group is connected to the second positive electrode current collector, and the negative electrode tab group is connected to the second negative electrode current collector.

[0031] Figure 7 It is a view showing the surface of the sealing plate on the electrode body side after the first positive electrode current collector and the first negative electrode current collector are attached.

[0032] Figure 8 This is a view showing the surface of the sealing plate on the electrode body side after the second positive electrode current collector is attached to the first positive electrode current collector and the second negative electrode current collector is attached to the first negative electrode current collector.

[0033] Fig. 9 It is a schematic perspective view of an electrode body.

[0034] Fig.10 It is a schematic perspective view showing an electrode body and a capturing member according to an embodiment.

[0035] Fig.11 It is a schematic perspective view showing an electrode body and a capturing member according to another embodiment.

[0036] Fig.12 This is a schematic perspective view showing an electrode body and a capturing member according to still another embodiment. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following description of preferred embodiments is essentially for illustration only and is not intended to limit the present invention, its applicable objects or its uses. In the following drawings, for simplicity of description, the same reference numerals are used to represent components having substantially the same functions.

[0038] (Implementation Method 1)

[0039] The following describes the structure of a rectangular secondary battery 20 as a secondary battery according to Embodiment 1. In addition, the present invention is not limited to the following embodiment.

[0040] like Figure 1 and Figure 2 As shown, the square secondary battery 20 has a battery case 100, which includes a square outer body 1 with a bottomed square tube having an opening and a sealing plate 2 that seals the opening of the square outer body 1. The square outer body 1 and the sealing plate 2 are preferably made of metal. An electrolyte and an electrode body 3 including a positive electrode plate and a negative electrode plate are contained in the square outer body 1. As described later, in this embodiment, the electrode body 3 includes a first electrode body element and a second electrode body element, and the two electrode body elements have the same structure.

[0041] A positive electrode tab group 40A including a plurality of positive electrode tabs 40 and a negative electrode tab group 50A including a plurality of negative electrode tabs 50 are provided at the end of the electrode body 3 on the sealing plate 2 side. The positive electrode tab group 40A is electrically connected to the positive electrode terminal 7 via the second positive electrode collector (positive electrode collector) 6b and the first positive electrode collector 6a. The negative electrode tab group 50A is electrically connected to the negative electrode terminal 9 via the second negative electrode collector (negative electrode collector) 8b and the first negative electrode collector 8a.

[0042] The first positive electrode collector 6a, the second positive electrode collector 6b, and the positive electrode terminal 7 are preferably made of metal, more preferably aluminum or an aluminum alloy. An external insulating member 10 made of resin is arranged between the positive electrode terminal 7 and the sealing plate 2. An internal insulating member 11 made of resin is arranged between the first positive electrode collector 6a and the second positive electrode collector 6b and the sealing plate 2.

[0043] The first negative electrode collector 8a, the second negative electrode collector 8b and the negative terminal 9 are preferably made of metal, more preferably copper or a copper alloy. In addition, the negative terminal 9 preferably has a portion formed of aluminum or an aluminum alloy and a portion formed of copper or a copper alloy. In this case, it is preferred that the portion formed of copper or a copper alloy is connected to the first negative electrode collector 8a, and the portion formed of aluminum or an aluminum alloy protrudes to the outside than the sealing plate 2. An external side insulating member 12 made of resin is arranged between the negative terminal 9 and the sealing plate 2. An internal side insulating member 13 made of resin is arranged between the first negative electrode collector 8a and the second negative electrode collector 8b and the sealing plate 2.

[0044] An electrode body holder 14 formed of a resin sheet is arranged between the electrode body 3 and the square outer body 1. The electrode body holder 14 is preferably formed by bending a resin insulating sheet into a bag or box shape. The electrode body holder 14 is used to reliably maintain an electrically insulating state between the electrode body 3 and the square outer body 1. In addition, in order to more reliably prevent the electrode body 3 from contacting the square outer body 1, it is preferred that a plurality of pores are not formed in the electrode body holder 14. That is, the electrode body holder 14 is preferably non-porous.

[0045] 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 breaks when the pressure in the battery case 100 exceeds a predetermined value to discharge the gas in the battery case 100 to the outside of the battery case 100.

[0046] Next, a method for manufacturing the rectangular secondary battery 20 and each structure thereof will be described in detail.

[0047] [Positive plate]

[0048] First, a method for manufacturing a positive electrode plate will be described.

[0049] [Preparation of positive electrode active material mixture layer slurry]

[0050] A positive electrode active material mixture layer slurry is prepared by mixing 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 a mass ratio of lithium nickel cobalt manganese composite oxide: PVdF: carbon material of 97.5:1:1.5.

[0051] [Preparation of positive electrode protective layer slurry]

[0052] Alumina powder, graphite as a conductive material, polyvinylidene fluoride (PVdF) as a binder, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium were mixed at a mass ratio of alumina powder:graphite:PVdF of 83:3:14 to prepare a protective layer slurry.

[0053] [Formation of Positive Electrode Active Material Mixture Layer and Positive Electrode Protective Layer]

[0054] The positive electrode active material mixture layer slurry and the positive electrode protective layer slurry prepared by the above method were applied to both sides of the aluminum foil with a thickness of 15 μm as the positive electrode core using a die coating machine. At this time, the positive electrode active material mixture layer slurry was applied to the center of the positive electrode core in the width direction. In addition, the positive electrode protective layer slurry was applied to both ends of the region in the width direction where the positive electrode active material mixture layer slurry was applied.

[0055] The positive electrode core coated with the positive electrode active material mixture layer slurry and the positive electrode protective layer slurry is dried to remove the NMP in the slurry. Thus, the positive electrode active material mixture layer and the protective layer are formed. After that, it is passed between a pair of pressing rollers to compress the positive electrode active material mixture layer to form a positive electrode original plate. The positive electrode original plate is cut into a predetermined size.

[0056] Figure 3 It is a top view of the positive electrode plate 4 .

[0057] [Negative plate]

[0058] Next, a method for manufacturing the negative electrode plate will be described.

[0059] [Preparation of negative electrode active material mixture layer slurry]

[0060] Graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium were mixed at a mass ratio of graphite:SBR:CMC of 98:1:1 to prepare a negative electrode active material mixture layer slurry.

[0061] [Formation of Negative Electrode Active Material Mixture Layer]

[0062] The negative electrode active material mixture layer slurry prepared in the above-described manner was applied to both surfaces of a copper foil having a thickness of 8 μm, which was a negative electrode core, using a die coater.

[0063] The negative electrode core coated with the negative electrode active material mixture layer slurry is dried to remove the water in the slurry. Thus, the negative electrode active material mixture layer is formed. After that, it is passed between a pair of pressing rollers to compress the negative electrode active material mixture layer to form a negative electrode original plate. The negative electrode original plate is cut into a predetermined size.

[0064] Figure 4 It is a top view of the negative electrode plate 5 .

[0065] [Production of electrode body]

[0066] The positive electrode plate 4 and the negative electrode plate 5 produced by the above-described method are stacked with a separator interposed therebetween to produce a stacked electrode body 3 . Figure 5 It is a plan view of the electrode body 3. A positive electrode tab group 40A including a plurality of positive electrode tabs 40 and a negative electrode tab group 50A including a plurality of negative electrode tabs 50 are provided at one end of the electrode body 3.

[0067] Then, as described later, a porous body is disposed on the stacking end surface of the electrode body 3 (a surface parallel to the stacking direction of the positive electrode plates 4 and the negative electrode plates 5 , a surface where the end surfaces of the positive electrode plates 4 and the negative electrode plates 5 are exposed).

[0068] [Connection between current collector and tab]

[0069] In this embodiment, if Figure 6 As shown, the electrode body 3 includes a first electrode body element 3a and a second electrode body element 3b. The first electrode body element 3a and the second electrode body element 3b are manufactured by the same method as the manufacturing method of the electrode body 3 described above.

[0070] The first positive electrode tab group 40A1 of the first electrode body element 3a and the second positive electrode tab group 40A2 of the second electrode body element 3b are both connected to the second positive electrode collector (positive electrode collector) 6b, and the first negative electrode tab group 50A1 of the first electrode body element 3a and the second negative electrode tab group 50A2 of the second electrode body element 3b are both connected to the second negative electrode collector (negative electrode collector) 8b. The first positive electrode tab group 40A1 is welded to the second positive electrode collector 6b to form a welded connection 60a, and the second positive electrode tab group 40A2 is welded to the second positive electrode collector 6b to form a welded connection 60b. The negative electrode tab group 50A1 is welded to the second negative electrode collector 8b to form a welded connection 61a, and the negative electrode tab group 50A2 is welded to the second negative electrode collector 8b to form a welded connection 61b.

[0071] The second positive electrode current collector 6b is formed with a thin wall portion 6c, and a current collector opening 6d is formed in the thin wall portion 6c. The second positive electrode current collector 6b is connected to the first positive electrode current collector 6a in the thin wall portion 6c. A current collector through hole 6e is formed at a position of the second positive electrode current collector 6b that is opposite to the electrolyte injection hole 15 of the sealing plate 2.

[0072] The second negative electrode current collector 8b has a thin portion 8c, and a current collector opening 8d is formed in the thin portion 8c. The second negative electrode current collector 8b is connected to the first negative electrode current collector 8a at the thin portion 8c.

[0073] The positive electrode tab group 40A and the second positive electrode current collector 6 b can be connected by ultrasonic welding, resistance welding, laser welding, or the like.

[0074] [Installation of components on the sealing plate]

[0075] Figure 7 1 is a diagram showing the surface of the sealing plate 2 on the battery interior side to which the various components are mounted. The various components are mounted on the sealing plate 2 in the following manner.

[0076] An external insulating member 10 is arranged on the outer side of the battery around the positive terminal insertion hole 2a of the sealing plate 2. An internal insulating member 11 and a first positive electrode collector 6a are arranged on the inner side of the battery around the positive terminal insertion hole 2a of the sealing plate 2. Afterwards, the positive terminal 7 is inserted from the outside of the battery into the through hole of the external insulating member 10, the positive terminal insertion hole 2a of the sealing plate 2, the through hole of the internal insulating member 11, and the terminal connection hole of the first positive electrode collector 6a, and the top of the positive terminal 7 is embedded in the first positive electrode collector 6a. Thus, the positive terminal 7 and the first positive electrode collector 6a are fixed to the sealing plate 2. In addition, it is preferred that the embedded portion of the positive terminal 7 is welded and connected to the first positive electrode collector 6a.

[0077] An external insulating member 12 is arranged on the outer side of the battery around the negative terminal insertion hole 2b of the sealing plate 2. An internal insulating member 13 and a first negative electrode collector 8a are arranged on the inner side of the battery around the negative terminal insertion hole 2b of the sealing plate 2. After that, 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 insertion hole 2b of the sealing plate 2, the through hole of the internal insulating member 13, and the terminal connection hole of the first negative electrode collector 8a, and the top of the negative terminal 9 is embedded in the first negative electrode collector 8a. Thus, the negative terminal 9 and the first negative electrode collector 8a are fixed to the sealing plate 2. In addition, it is preferred that the embedded portion of the negative terminal 9 is welded to the first negative electrode collector 8a.

[0078] A liquid injection opening 11a is provided at a portion of the inner insulating member 11 that faces the electrolyte injection hole 15 provided in the sealing plate 2. A cylindrical portion 11b is provided at the edge of the liquid injection opening 11a.

[0079] [Connection between the first current collector and the second current collector]

[0080] Figure 8 This is a view showing the surface of the sealing plate 2 on the battery interior side after the second positive electrode collector 6b is attached to the first positive electrode collector 6a and the second negative electrode collector 8b is attached to the first negative electrode collector 8a.

[0081] The second positive electrode collector 6b connected to the first positive electrode tab group 40A1 and the second positive electrode tab group 40A2 is arranged on the inner side insulating member 11 in a manner that a portion thereof overlaps with the first positive electrode collector 6a. Then, the thin-walled portion 6c is irradiated with laser, and the second positive electrode collector 6b is welded to the first positive electrode collector 6a to form a welded connection portion 62. In addition, the second negative electrode collector 8b connected to the first negative electrode tab group 50A1 and the second negative electrode tab group 50A2 is arranged on the inner side insulating member 13 in a manner that a portion thereof overlaps with the first negative electrode collector 8a. Then, the thin-walled portion 8c is irradiated with laser, and the second negative electrode collector 8b is welded to the first negative electrode collector 8a to form a welded connection portion 63.

[0082] [Manufacturing of Secondary Batteries]

[0083] To make Figure 8 The two positive electrode tab groups 40A1, 40A2 and the two negative electrode tab groups 50A1, 50A2 are bent in such a manner that the upper surface of the first electrode body element 3a and the upper surface of the second electrode body element 3b are in contact directly or through other components. Thus, the two electrode body elements 3a, 3b are integrated into one. Then, the two electrode body elements 3a, 3b are arranged in an electrode body holder 14 formed of an insulating sheet and formed into a box shape or a bag shape.

[0084] The first positive electrode tab group 40A1 and the second positive electrode tab group 40A2 are bent in different directions, respectively. Also, the first negative electrode tab group 50A1 and the second negative electrode tab group 50A2 are bent in different directions, respectively.

[0085] The two electrode body elements 3a and 3b surrounded by the electrode body holder 14 are inserted into the square outer body 1. Then, the sealing plate 2 is welded to the square outer body 1, and the opening of the square outer body 1 is sealed by the sealing plate 2. Then, the electrolyte is injected into the square outer body 1 through the electrolyte injection hole 15 provided in the sealing plate 2. After that, the electrolyte injection hole 15 is sealed with a sealing member such as a blind rivet. In this way, the square secondary battery 20 is completed.

[0086] <Attachment of porous body to electrode body and electrode body element>

[0087] In this embodiment, if Fig. 9 As shown, the stacked end faces of the electrode body 3 (the first electrode body element 3a and the second electrode body element 3b) have four faces, and the first end face 31 on which a plurality of positive electrode tabs 40 and negative electrode tabs 50 protrude is as shown in FIG. Figure 8 As described in the column [Manufacturing of secondary battery], the plurality of positive electrode tabs 40 are bundled together to form a positive electrode tab group 40A (a first positive electrode tab group 40A1, a second positive electrode tab group 40A2), and are welded to the second positive electrode current collector 6b ( Figure 6 ). Similarly, the plurality of negative electrode tabs 50 are bundled together to form a negative electrode tab group 50A (a first negative electrode tab group 50A1 and a second negative electrode tab group 50A2), and are welded to the second negative electrode current collector 8b.

[0088] The inventors of the present invention have conducted research and found that when performing these welding operations, dust is generated and a lot of metal powder (foreign matter) is generated. Fig. 9 When the electrode body 3 shown is welded to the second positive electrode collector 6b and the second negative electrode collector 8b respectively, metal powder will adhere to the second positive electrode collector 6b, the portion of the positive electrode tab group 40A located near the second positive electrode collector 6b, the second negative electrode collector 8b and the portion of the negative electrode tab group 50A located near the second negative electrode collector 8b.

[0089] When the electrolyte is subsequently injected, the metal powder is pressed into the interior of the electrode body 3 , which may cause an internal short circuit.

[0090] In particular, when the number of positive plates 4 and negative plates 5 constituting the electrode body 3 (the first electrode body element 3a and the second electrode body element 3b) is increased in order to increase the output of the battery, the number of positive electrode tabs 40 included in the positive electrode tab group 40A (the first positive electrode tab group 40A1 and the second positive electrode tab group 40A2) and the number of negative electrode tabs 50 included in the negative electrode tab group 50A (the first negative electrode tab group 50A1 and the second negative electrode tab group 50A2) also increase accordingly, and therefore, when welding them to the second positive electrode collector 6b and the second negative electrode collector 8b, it is necessary to increase the welding output. If the welding output is increased, the amount of metal powder generated will increase, and therefore the possibility of internal short circuit will increase.

[0091] Therefore, in this embodiment, if Fig.10 As shown, the capture members 70, 71, 72 formed of a nonwoven fabric as an electrically insulating porous body are arranged to cover the surface of the electrode body 3 parallel to the stacking direction of the positive electrode plate 4 and the negative electrode plate 5 and are the stacking end faces (first end face 31, second end face 32, third end face) where the end faces of the positive electrode plate 4 and the negative electrode plate 5 are exposed. In this case, it is preferred to fix the capture members 70, 71, 72 to the stacking end faces using an adhesive, an adhesive tape, etc. When fixing, the capture members 70, 71, 72 can be bonded to the stacking end faces, or the surface of the outermost layer of the electrode body 3 after stacking can be bonded to the capture members 70, 71, 72. In addition, since the positive electrode tab group 40A and the negative electrode tab group 50A protrude from the first end face 31, holes 77, 77 for the positive electrode tab group 40A and the negative electrode tab group 50A to pass through are formed in the first capture member 71.

[0092] If the capturing members 70, 71, 72 are configured in this way, the capturing members 70, 71, 72 covering the first end face 31, the second end face 32 and the third end face will capture the metal powder generated when the positive electrode tab group 40A is welded to the second positive electrode collector 6b and when the negative electrode tab group 50A is welded to the second negative electrode collector 8b, thereby preventing the metal powder from adhering to the first end face 31, the second end face 32 and the third end face.

[0093] When the assembly of the rectangular secondary battery 20 is completed, the first capturing member 70 is disposed between the first end face 31 and the second positive electrode current collector 6b and between the first end face 31 and the second negative electrode current collector 8b. Therefore, even if the electrolyte is injected, the metal powder remains captured by the hole portions of the first capturing member 70, the second capturing member 71, and the third capturing member 72 and does not enter the interior of the electrode body 3. Therefore, an internal short circuit caused by the metal powder can be prevented.

[0094] In addition, only the first catching member 70 may be provided, and the second catching member 71 and the third catching member 72 may be omitted.

[0095] Preferably, the first capturing member 70 is disposed on the end surfaces of the first electrode body element 3a and the second electrode body element 3b before welding the positive electrode tab group 40A to the second positive electrode current collector 6b and before welding the negative electrode tab group 50A to the second negative electrode current collector 8b.

[0096] At this time, the first catching member 70 disposed on the end surface of the first electrode body element 3a and the first catching member 70 disposed on the end surface of the second electrode body element 3b are preferably separate members. In addition, it is preferred that each of the first catching members 70 has a hole for inserting the positive electrode tab group 40A and the negative electrode tab group 50A.

[0097] The average pore diameter of the nonwoven fabric (porous body) constituting the capture members 70, 71, and 72 is not particularly limited as long as it is a size that can capture foreign matter such as metal foreign matter, and is preferably in the range of 20 μm or more and 100 μm or less. In particular, with regard to metal foreign matter that affects the short circuit and performance degradation of the battery, most of the metal foreign matter of about 20 μm in size is mixed into the square secondary battery 20. Therefore, if the average pore diameter of the porous body is less than 20 μm, it is sometimes difficult to capture metal foreign matter, and if the average pore diameter of the porous body is greater than 100 μm, it is sometimes difficult to keep the captured metal foreign matter in the porous body. The average pore diameter of the porous body is the average value of the pore diameters of 10 arbitrary locations selected on the image and obtained by SEM measurement.

[0098] The nonwoven fabric preferably contains fibers made of a resin such as polyester, polyolefin, polyamide, polyurethane or polystyrene, or electrically insulating fibers such as glass fibers, ceramic fibers or cellulose fibers, and a known method can be used for its production.

[0099] (Implementation Method 2)

[0100] The battery of the second embodiment is the same as the first embodiment except that the shape of the capturing member is different from that of the first embodiment. Therefore, the differences from the first embodiment will be described below.

[0101] Fig.11 The shape of the capture member 75 in this embodiment is shown. In Embodiment 1, an independent capture member 70, 71, 72 is configured for each of the four stacked end faces, but in this embodiment, it is configured to continuously cover the four stacked end faces with a single strip-shaped capture member 75. That is, a single capture member 75 is configured, for example, to cover the first end face 31, then bends to cover the second end face 32, and then further bends to cover the third end face. As in Embodiment 1, holes 77, 77 for the positive electrode tab group 40A and the negative electrode tab group 50A to pass through are formed in the portion of the capture member 75 covering the first end face 31.

[0102] Compared with the first embodiment, in the present embodiment, it is easier to attach the capture member 75 to the electrode body 3 , and the effects obtained in the first embodiment can also be obtained in the second embodiment in the same manner.

[0103] (Implementation method 3)

[0104] The battery of the third embodiment is the same as the first embodiment except that the shape of the capturing member is different from that of the first embodiment. Therefore, the differences from the first embodiment will be described below.

[0105] Fig.12 The shapes of the capture members 71, 72, and 73 in this embodiment are shown. The second capture member 71 and the third capture member 72 are the same capture members as those in Embodiment 1, but the first capture member 73 is different from that in Embodiment 1. Specifically, the first capture member 73 in this embodiment is not formed with holes 77, 77 through which the positive electrode tab group 40A and the negative electrode tab group 50A pass, but instead has an H-shaped cutout 79.

[0106] The length of the cut corresponding to the vertical line of the H-shape is substantially the same as the width of each of the positive electrode tab 40 and the negative electrode tab 50 , and the length of the cut corresponding to the horizontal line of the H-shape is substantially the same as the width of each of the positive electrode tab group 40A and the negative electrode tab group 50A in the stacking direction.

[0107] The two tongue-shaped non-woven fabric parts of the first capturing member 73 of the present embodiment, which are separated from the cutout corresponding to the horizontal line of the letter H to the two sides, are arranged on the side portions of the positive electrode tab group 40A and the negative electrode tab group 50A respectively (the side arrangement portion of the positive electrode tab 40 constituting the positive electrode tab group 40A and the side arrangement portion of the negative electrode tab 50 constituting the negative electrode tab group 50A), and cover these side portions, thereby preventing foreign matter such as metal powder from entering between adjacent positive electrode tabs 40, 40 and between adjacent negative electrode tabs 50, 50 from these side portions.

[0108] Compared with the first embodiment, in the present embodiment, foreign matter can be more reliably prevented from entering the interior of the electrode body 3 .

[0109] (Other embodiments)

[0110] The above-mentioned embodiments are examples of the present invention, and the present invention is not limited to these examples, and these examples may be combined with known techniques, conventional techniques, and known techniques, or partially replaced. In addition, the modified inventions that are easily conceived by those skilled in the art are also included in the present invention.

[0111] The electrode body may be a structure in which the positive electrode plate, the negative electrode plate, and the separator are stacked and then wound. The electrode body element may also be a wound structure.

[0112] In the above embodiment, an example in which two electrode body elements are arranged in an exterior body is shown, but the number of electrode body elements may be one or three or more.

[0113] In the above-described embodiment, an example is shown in which the positive electrode current collector and the negative electrode current collector are each composed of two members, but the positive electrode current collector and the negative electrode current collector may each be composed of one member.

[0114] As for the positive electrode plate, the negative electrode plate, the separator, the electrolyte, and the like, known materials can be used.

[0115] The electrically insulating porous body constituting the capture component may be, in addition to nonwoven fabric, a porous polymer film formed of polyolefin resins, fluorine resins, etc., or a sheet formed of inorganic materials such as zeolite, zirconia, silica, alumina, titanium dioxide and other ceramic materials.

[0116] The capturing member may be arranged so as to cover at least the first end surface, and preferably so as to cover the second end surface as well.

[0117] Description of Reference Numerals

[0118] 1. Square outer casing (outer casing); 2. Sealing plate; 3. Electrode body; 3a. First electrode body element; 3b. Second electrode body element; 4. Positive plate; 5. Negative plate; 6a. First positive electrode collector; 6b. Second positive electrode collector; 7. Positive terminal (positive external terminal); 8a. First negative electrode collector; 8b. Second negative electrode collector; 9. Negative terminal (negative external terminal); 14. Electrode body holder (insulating sheet); 15. Electrolyte injection hole; 20. Square secondary battery (battery); 31. First end face (one of the faces of the electrode body parallel to the stacking direction of the positive plate and the negative plate) , a first end face of the electrode body; 32, a second end face (the other face of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate); 40, a positive electrode tab; 40A, a positive electrode tab group; 40A1, a first positive electrode tab group; 40A2, a second positive electrode tab group; 50, a negative electrode tab; 50A, a negative electrode tab group; 50A1, a first negative electrode tab group; 50A2, a second negative electrode tab group; 60, 61, 62, 63, a welding connection portion; 70, 73, a first capturing member (porous body); 71, a second capturing member (porous body); 72, a third capturing member (porous body); 75, a capturing member (porous body).

Claims

1. A battery, wherein: The battery includes: The electrode body is formed by stacking the positive electrode plate and the negative electrode plate with the separator between them; an outer casing having an opening, the outer casing housing the electrode body; a sealing plate that closes the opening; and A positive electrode external terminal and a negative electrode external terminal, wherein the positive electrode external terminal and the negative electrode external terminal are mounted on the sealing plate, The sealing plate is provided with a liquid injection hole for injecting electrolyte into the outer casing. One of the surfaces of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate faces the sealing plate, The positive electrode tab of the positive electrode plate provided on the one surface side in a manner protruding from the one surface is electrically connected to the positive electrode external terminal via a positive electrode current collector disposed between the electrode body and the sealing plate. The negative electrode tab of the negative electrode plate provided on the one surface side in a manner protruding from the one surface is electrically connected to the negative electrode external terminal via a negative electrode current collector disposed between the electrode body and the sealing plate. The positive electrode tab and the positive electrode current collector are welded together. The negative electrode tab and the negative electrode current collector are welded together. An electrically insulating porous body is disposed between the one surface and the positive electrode current collector and between the one surface and the negative electrode current collector, and the porous body covers the one surface so as to surround the positive electrode tab and the negative electrode tab. In the positive electrode tab and the negative electrode tab, at least a portion of a side end portion protruding from the one surface is covered with the porous body.

2. The battery according to claim 1, wherein The porous body is also disposed on the other surface of the electrode body that is parallel to the stacking direction of the positive electrode plate and the negative electrode plate.

3. The battery according to claim 1 or 2, wherein: The electrode body comprises: a first electrode body element, comprising the positive electrode plate and the negative electrode plate; and a second electrode body element, comprising the positive electrode plate and the negative electrode plate, The first electrode body element includes a first positive electrode tab group including a plurality of the positive electrode tabs and a first negative electrode tab group including a plurality of the negative electrode tabs. The second electrode body element includes a second positive electrode tab group including a plurality of the positive electrode tabs and a second negative electrode tab group including a plurality of the negative electrode tabs. The first positive electrode tab group and the second positive electrode tab group are respectively welded to the positive electrode collector. The first negative electrode tab group and the second negative electrode tab group are respectively welded to the negative electrode collector. The porous bodies are disposed on the surface of the first electrode body element constituting the one surface and the surface of the second electrode body element constituting the one surface, respectively.

4. The battery according to claim 1 or 2, wherein An insulating sheet is disposed between the outer casing and the electrode body.

5. The battery according to claim 1 or 2, wherein The porous body is formed of a nonwoven fabric.

6. A method for manufacturing a battery, wherein: The manufacturing method of the battery comprises the following steps: A step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form an electrode body; A step of covering at least one surface of the electrode body parallel to the stacking direction of the positive electrode plate and the negative electrode plate, on which the positive electrode tab and the negative electrode tab are arranged, with an electrically insulating porous body so as to surround the periphery of the positive electrode tab and the periphery of the negative electrode tab, and covering at least a portion of the lateral end portions of the positive electrode tab and the negative electrode tab protruding from the one surface with the porous body; The step of welding the positive electrode tab to the positive electrode collector and welding the negative electrode tab to the negative electrode collector; The step of electrically connecting the positive electrode current collector to the positive electrode external terminal and electrically connecting the negative electrode current collector to the negative electrode external terminal; a step of inserting the electrode body into an outer casing having an opening and sealing the opening with a sealing plate; and and injecting an electrolyte solution into the outer casing from an injection hole provided in the sealing plate.

7. A method for manufacturing a battery, wherein: The manufacturing method of the battery comprises the following steps: A step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form a first electrode body element; A step of stacking a positive electrode plate including a positive electrode tab and a negative electrode plate including a negative electrode tab via a separator to form a second electrode body element; A step of covering at least one of the surfaces of the first electrode element parallel to the stacking direction of the positive electrode plate and the negative electrode plate, on which the positive electrode tab and the negative electrode tab are arranged, with an electrically insulating porous body so as to surround the periphery of the positive electrode tab and the periphery of the negative electrode tab, and covering at least a portion of the lateral end portions of the positive electrode tab and the negative electrode tab protruding from the one surface with the porous body; A step of covering, with an electrically insulating porous body, at least a surface on which the positive electrode tab and the negative electrode tab are arranged, among surfaces of the second electrode element parallel to the stacking direction of the positive electrode plate and the negative electrode plate; The step of welding the positive electrode tab and the positive electrode current collector of the first electrode body element and welding the negative electrode tab and the negative electrode current collector; The step of electrically connecting the positive electrode current collector and the positive electrode external terminal and electrically connecting the negative electrode current collector and the negative electrode external terminal; and A step of integrating the first electrode body element and the second electrode body element into one.

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