Secondary battery

Abstract

The exposed portion of the wound positive electrode core is bundled and connected to the positive electrode collector. A tape is attached across the separator located on the outermost surface of the wound electrode body and the outermost surface of the exposed portion of the wound positive electrode core. The tape has a porous substrate and an adhesive layer provided on the substrate. The tape has an area where the adhesive layer (b) is not provided on the substrate (a) between the adhesive portion between the tape and the separator located on the outermost surface of the wound electrode body and the adhesive portion between the tape and the outermost surface of the exposed portion of the wound positive electrode core.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery. Background Art

[0002] Secondary 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] The above-mentioned secondary batteries sometimes have foreign matter mixed in during their assembly, especially when the mixed foreign matter is a conductive foreign matter such as a metal foreign matter, which sometimes causes an internal short circuit. For example, if a metal foreign matter is attached to the positive plate, due to the high potential of the positive plate, the metal foreign matter dissolves into metal ions in the electrolyte, and if the metal ions reach the negative plate, they precipitate as metal. In addition, the metal precipitates in a manner that grows toward the positive plate, and when the metal pierces the separator and contacts the positive plate, an internal short circuit is caused. In addition, the mixed metal foreign matter may also directly pierce the separator and cause an internal short circuit.

[0004] Patent Document 1 proposes a secondary battery for preventing internal short circuits caused by foreign matter mixed in, wherein an insulating member covers the positive electrode exposure portion or the negative electrode exposure portion together with the end of the separator adjacent to the periphery of the positive electrode exposure portion or the negative electrode exposure portion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-49073 Summary of the invention

[0008] A secondary battery according to a technical solution of the present disclosure has:

[0009] a first electrode plate having a first electrode active material layer formed on a first electrode core;

[0010] a second electrode plate having a second electrode active material layer formed on a second electrode core; and

[0011] A flat wound electrode body is formed by winding the first electrode plate and the second electrode plate with a separator interposed therebetween.

[0012] in,

[0013] The wound electrode body has a first electrode core exposed portion wound at one end portion in a direction in which a winding axis of the wound electrode body extends, and has a second electrode core exposed portion wound at the other end portion in a direction in which the winding axis extends,

[0014] The exposed portion of the wound first electrode core is bundled and connected to the first electrode current collector.

[0015] A separator is disposed on the outermost surface of the wound electrode body.

[0016] A tape is attached across the separator disposed on the outermost surface of the wound electrode body and the outermost surface of the exposed portion of the wound first electrode core body.

[0017] The belt comprises a porous base material and an adhesive layer provided on the base material.

[0018] The tape has a region where the adhesive layer is not provided on the substrate between a bonding portion between the tape and a separator disposed on the outermost surface of the wound electrode body and a bonding portion between the tape and the outermost surface of the exposed portion of the wound first electrode core.

[0019] According to the structure of the secondary battery of one technical solution of the present disclosure, a tape is attached across the separator arranged on the outermost surface of the wound electrode body and the outermost surface of the exposed portion of the wound first electrode core, so that foreign matter can be prevented from invading the wound electrode body from between the separator located on the outermost surface of the wound electrode body and the exposed portion of the wound first electrode core. In addition, the base material of the tape is porous, and an area where no adhesive layer is provided on the base material is formed between the bonding portion between the tape and the separator arranged on the outermost surface of the wound electrode body and the bonding portion between the tape and the outermost surface of the exposed portion of the wound first electrode core, so that the electrolyte will not be hindered from infiltrating into the wound electrode body. Therefore, it is possible to prevent the generation of a portion of insufficient electrolyte in the wound electrode body. In addition, when a portion of insufficient electrolyte is generated in the wound electrode body, problems such as reduced battery characteristics or lithium precipitation may occur.

[0020] The porous substrate is preferably a nonwoven fabric.

[0021] Preferably, the nonwoven fabric has a unit area weight of 40 g / m 2 ~100g / m 2 ,

[0022] The average fiber diameter of the fibers constituting the nonwoven fabric is 8 μm to 60 μm.

[0023] Preferably, the first electrode plate is a positive electrode plate, and the second electrode plate is a negative electrode plate.

[0024] According to one aspect of the present disclosure, the electrolyte solution is not blocked from penetrating into the wound electrode body, and metallic foreign matter can be prevented from invading the wound electrode body. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view showing the interior of the secondary battery according to the embodiment, with the front portion of the battery case and the front portion of the insulating sheet removed.

[0026] Figure 2 It is a top view of the secondary battery in the embodiment.

[0027] Figure 3A It is a plan view of the positive electrode plate in the embodiment.

[0028] Figure 3B It is a plan view of the negative electrode plate in the embodiment.

[0029] Figure 4 It is a diagram showing a method of sandwiching the exposed portion of the wound positive electrode substrate and the positive electrode current collector by using a horn and anvil when ultrasonic bonding is performed in the manufacturing process of the secondary battery according to the embodiment.

[0030] Figure 5 It is a cross-sectional view of the outermost periphery of the exposed positive electrode core portion of the wound electrode body in the embodiment, and is a cross-sectional view along the direction of the winding axis of the wound electrode body.

[0031] Figure 6 It is a plan view of a belt according to an embodiment.

[0032] Fig. 7A It is a plan view of a flat wound electrode body in the embodiment.

[0033] Figure 7B It is a side view of the flat wound electrode body in the embodiment.

[0034] Figure 8 This is a cross-sectional view of the vicinity of the outermost periphery of the exposed portion of the positive electrode core of a wound electrode body according to another embodiment, and is a cross-sectional view along the direction of the winding axis of the wound electrode body.

[0035] Fig. 9 It is a cross-sectional view of the outermost periphery of the exposed positive electrode core portion of the wound electrode body in a state where no tape is attached, and is a cross-sectional view along the direction of the winding axis of the wound electrode body. DETAILED DESCRIPTION

[0036] A secondary battery according to one embodiment of the present disclosure will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical concept of the present invention.

[0037] First, the structure of a prismatic secondary battery as a secondary battery of one embodiment will be described.

[0038] like Figure 1 and Figure 2 As shown, the square secondary battery 100 has a square outer body 1 with an opening at the top and a sealing plate 2 for sealing the opening. The battery case 200 is composed of the square outer body 1 and the sealing plate 2. The square outer body 1 and the sealing plate 2 are respectively made of metal, for example, aluminum or aluminum alloy. A flat wound electrode body 3 formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate with a strip-shaped separator is contained in the square outer body 1 together with a non-aqueous electrolyte. The positive electrode plate is a component in which a positive electrode active material layer containing a positive electrode active material is formed on a metal positive electrode core. The positive electrode plate has a positive electrode core exposed portion in which the positive electrode core is exposed along the length direction. The negative electrode plate is a component in which a negative electrode active material layer containing a negative electrode active material is formed on a metal negative electrode core. The negative electrode plate has a negative electrode core exposed portion in which the negative electrode core is exposed along the length direction. The positive electrode core can be made of aluminum or aluminum alloy, for example. The negative electrode core can be made of, for example, copper or a copper alloy.

[0039] In the wound electrode body 3, a positive electrode core body, i.e., a positive electrode core body exposed portion 4c, on which a positive electrode active material layer is not formed is arranged in a wound state at one end side in the direction in which the winding axis of the wound electrode body 3 extends. The positive electrode core body exposed portion 4c is wound without a separator or a negative electrode plate to form a stacked state. A positive electrode current collector 6 is connected to the wound positive electrode core body exposed portion 4c. The positive electrode current collector 6 can be made of, for example, aluminum or an aluminum alloy.

[0040] In the wound electrode body 3, a negative electrode core body, i.e., a negative electrode core body exposed portion 5c, which is a negative electrode core body without a negative electrode active material layer, is arranged in a wound state at the other end side in the direction in which the winding axis of the wound electrode body 3 extends. The negative electrode core body exposed portion 5c is wound without a separator or a positive electrode plate to form a stacked state. A negative electrode current collector 8 is connected to the wound negative electrode core body exposed portion 5c. The negative electrode current collector 8 can be made of, for example, copper or a copper alloy.

[0041] The tape 30 is pasted across the separator 20 located at the outermost surface of the wound electrode body 3 and the outermost surface of the wound positive electrode core exposed portion 4 c .

[0042] The positive terminal 7 has a flange portion 7a disposed on the battery exterior side of the sealing plate 2 and an insertion portion inserted into the through hole provided in the sealing plate 2. The positive terminal 7 is made of metal, for example, it can be made of aluminum or an aluminum alloy. In addition, the negative terminal 9 has a flange portion 9a disposed on the battery exterior side of the sealing plate 2 and an insertion portion inserted into the through hole provided in the sealing plate 2. The negative terminal 9 is made of metal, for example, it can be made of copper or a copper alloy. In addition, the negative terminal 9 may also have a portion made of aluminum or an aluminum alloy and a portion made of copper or a copper alloy. In this case, it is preferred that the portion made of aluminum or an aluminum alloy protrudes outwardly from the sealing plate 2, and the portion made of copper or a copper alloy is connected to the negative electrode collector 8.

[0043] The positive electrode current collector 6 is fixed to the sealing plate 2 via an inner insulating member 10 made of resin, and the positive electrode terminal 7 is fixed to the sealing plate 2 via an outer insulating member 11 made of resin. In addition, the negative electrode current collector 8 is fixed to the sealing plate 2 via an inner insulating member 12 made of resin, and the negative electrode terminal 9 is fixed to the sealing plate 2 via an outer insulating member 13 made of resin.

[0044] The wound electrode body 3 is housed in the square outer body 1 in a state covered by the insulating sheet 14. The sealing plate 2 is connected to the opening edge of the square outer body 1 by welding by laser welding or the like. The sealing plate 2 has an electrolyte injection hole 16, and after the electrolyte is injected into the square outer body 1, the electrolyte injection hole 16 is sealed by a sealing plug 17. The sealing plate 2 is formed with a gas discharge valve 15 for discharging gas when the pressure in the battery case 200 becomes a predetermined value or more.

[0045] Hereinafter, the details of each structure will be described.

[0046] [Positive plate]

[0047] First, a method for manufacturing a positive electrode plate will be described.

[0048] [Preparation of positive electrode active material layer slurry]

[0049] 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 are mixed in a mass ratio of lithium nickel cobalt manganese composite oxide: PVdF: carbon material of 97.5:1:1.5 to prepare a positive electrode active material layer slurry.

[0050] [Formation of Positive Electrode Active Material Layer]

[0051] The positive electrode active material layer slurry prepared by the above method is applied to both sides of an aluminum foil with a thickness of 15 μm as a positive electrode core by a die coater. The positive electrode core coated with the positive electrode active material layer slurry is dried, and the NMP in the slurry is removed. Thus, a positive electrode active material layer is formed. Thereafter, a pair of pressing rollers are used to compress the positive electrode active material layer to form a positive electrode original plate. The positive electrode original plate is cut into a predetermined size.

[0052] Figure 3A 4 is a plan view of the positive electrode plate 4. Positive active material layers 4b are formed on both sides of the positive electrode core 4a. At one end of the positive electrode plate 4 in the width direction, a positive electrode core exposed portion 4c is provided along the length direction of the positive electrode plate 4 where the positive electrode core 4a is exposed.

[0053] [Negative plate]

[0054] Next, a method for manufacturing the negative electrode plate will be described.

[0055] [Preparation of Negative Electrode Active Material Layer Slurry]

[0056] 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 mixed at a mass ratio of graphite:SBR:CMC of 98:1:1 to prepare a negative electrode active material layer slurry.

[0057] [Formation of Negative Electrode Active Material Layer]

[0058] The negative electrode active material layer slurry prepared by the above method is applied to both sides of a copper foil with a thickness of 8 μm as a negative electrode core by a die coater. The negative electrode core coated with the negative electrode active material layer slurry is dried, and water in the slurry is removed. Thus, a negative electrode active material layer is formed. Thereafter, the negative electrode active material layer is compressed by a pair of pressing rollers to form a negative electrode original plate. The negative electrode original plate is cut into a predetermined size.

[0059] Figure 3B : is a plan view of the negative electrode plate 5. Negative electrode active material layers 5b are formed on both sides of the negative electrode core 5a. At one end of the negative electrode plate 5 in the width direction, a negative electrode core exposed portion 5c is provided along the length direction of the negative electrode plate 5 where the negative electrode core 5a is exposed.

[0060] [Production of wound electrode body]

[0061] The positive electrode plate 4 and the negative electrode plate 5 obtained by the above method are wound into a flat shape with a separator 20 made of polyethylene, for example, interposed therebetween, thereby obtaining a flat wound electrode body 3 having a positive electrode core exposed portion 4c wound at one end and a negative electrode core exposed portion 5c wound at the other end.

[0062] [Installing parts to the sealing plate]

[0063] Next, a method for attaching the positive electrode current collector 6 , the positive electrode terminal 7 , the negative electrode current collector 8 , and the negative electrode terminal 9 to the sealing plate 2 will be described.

[0064] First, an external insulating member 11 is arranged on the battery external side of the sealing plate 2, and an internal insulating member 10 and a positive electrode collector 6 are arranged on the battery internal side of the sealing plate 2. Next, the insertion portion of the positive terminal 7 is inserted from the battery external side into the through-holes respectively provided in the external insulating member 11, the sealing plate 2, the internal insulating member 10, and the positive electrode collector 6, and the top end side of the insertion portion of the positive terminal 7 is riveted to the positive electrode collector 6. Thus, the positive terminal 7, the external insulating member 11, the sealing plate 2, the internal insulating member 10, and the positive electrode collector 6 are fixed integrally. In addition, it is preferred that the riveted portion of the top end of the insertion portion of the positive terminal 7 is welded to the positive electrode collector 6.

[0065] Similarly, an external insulating member 13 is arranged on the battery external side of the sealing plate 2, and an internal insulating member 12 and a negative electrode collector 8 are arranged on the battery internal side of the sealing plate 2. Next, the insertion portion of the negative terminal 9 is inserted from the battery external side into the through holes respectively provided in the external insulating member 13, the sealing plate 2, the internal insulating member 12, and the negative electrode collector 8, and the top end side of the insertion portion of the negative terminal 9 is riveted to the negative electrode collector 8. Thus, the negative terminal 9, the external insulating member 13, the sealing plate 2, the internal insulating member 12, and the negative electrode collector 8 are fixed integrally. In addition, it is preferred that the riveted portion of the top end of the insertion portion of the negative terminal 9 is welded to the negative electrode collector 8.

[0066] [Attachment of current collector to wound electrode body]

[0067] The positive electrode current collector 6 is arranged on the outer surface of the positive electrode core exposed portion 4c stacked by winding. Figure 4 As shown, ultrasonic bonding is performed by sandwiching the stacked positive electrode core exposed portion 4c and the positive electrode current collector 6 with the welding head 90 and the anvil 91 of the ultrasonic bonding device. As a result, the wound positive electrode core exposed portion 4c is connected to the positive electrode current collector 6. In addition, the negative electrode core exposed portion 5c and the negative electrode current collector 8 stacked by winding can also be connected in the same way. In addition, the connection method is not limited to ultrasonic bonding, and resistance welding and laser welding can also be used.

[0068] [Structure of wound electrode body]

[0069] Fig. 9 4 is a cross-sectional view of the outermost surface of the exposed portion 4c of the wound positive electrode core of the wound electrode body 3. Fig. 9 It is a cross-sectional view along the direction of the winding axis of the wound electrode body 3. In addition, Fig. 9 3 is a diagram showing a state where the tape 30 is not attached to the wound electrode body 3. The separator 20 is arranged at the outermost periphery of the wound electrode body 3. In the wound electrode body 3, the outermost layer in the negative electrode plate 5 is located closer to the outermost layer in the positive electrode plate 4.

[0070] Although in Fig. 9 Although some parts are omitted, the exposed portion 4c of the positive electrode core body stacked by winding is bundled and connected to the positive electrode current collector 6. In the secondary battery having the wound electrode body 3, when the electrolyte is injected into the battery case 200, as shown in FIG. Fig. 9 As shown, there is a possibility that the foreign matter 80 may enter between the positive electrode plate 4 and the separator 20 or between the negative electrode plate 5 and the separator 20 together with the electrolyte, thereby causing an internal short circuit.

[0071] In order to suppress such an internal short circuit, when a tape is attached from the separator 20 located at the outermost periphery of the wound electrode body 3 to the outermost surface of the positive electrode core exposed portion 4c, it is possible to suppress the intrusion of foreign matter into the wound electrode body 3. However, it becomes difficult for the electrolyte to enter the wound electrode body 3. In addition, a portion where the electrolyte is insufficient is generated in the wound electrode body 3, which may cause uneven charging and discharging reactions or lithium metal precipitation.

[0072] [Paste of tape]

[0073] like Figure 5 As shown, a tape 30 is attached from the separator 20 located on the outermost surface of the flat wound electrode body 3 to the outermost surface of the wound positive electrode core exposed portion 4c. The tape 30 has a porous substrate 30a and an adhesive layer 30b provided on one surface of the substrate 30a.

[0074] like Figure 6 As shown, two adhesive layers 30b are provided on one surface of the base material 30a along the length direction of the tape 30. The two adhesive layers 30b are provided separately in the width direction of the tape 30.

[0075] like Figure 5 As shown, a separator 20 is arranged on the outermost surface of the wound electrode body 3. In the wound electrode body 3, the layer located closest to the outermost circumference of the wound electrode body 3 in the negative electrode plate 5 is closer to the outermost circumference of the wound electrode body 3 than the layer located closest to the outermost circumference of the wound electrode body 3 in the positive electrode plate 4.

[0076] The substrate 30a of the tape 30 is connected to the separator 20 located at the outermost periphery of the wound electrode body 3 by means of an adhesive layer 30b. In addition, the substrate 30a of the tape 30 is connected to the outermost surface of the exposed portion 4c of the wound positive electrode core by means of an adhesive layer 30b. Between the portion of the tape 30 connected to the separator 20 and the portion of the tape 30 connected to the exposed portion 4c of the positive electrode core, there is an area where the adhesive layer 30b is not formed on the substrate 30a. In addition, the substrate 30a is a porous member through which the electrolyte can pass. By having such a structure, the electrolyte will not be hindered from penetrating into the wound electrode body 3, and the intrusion of foreign matter into the wound electrode body 3 can be suppressed.

[0077] As the porous substrate 30a, nonwoven fabric is particularly preferred. When the substrate 30a is nonwoven fabric, foreign matter can be effectively captured. The nonwoven fabric is preferably composed of fibers such as fibers containing resins such as polyester, polyolefin, polyamide, polyurethane or polystyrene, glass fibers, ceramic fibers or cellulose fibers.

[0078] The weight per unit area of ​​the nonwoven fabric is preferably 40 g / m 2 ~100g / m 2 By setting the unit area weight of the nonwoven fabric to 40 g / m 2 As a result, it is possible to more effectively suppress the intrusion of foreign matter into the wound electrode body 3. In addition, by setting the weight per unit area of ​​the nonwoven fabric to 100 g / m 2 Next, a structure can be adopted in which the electrolyte solution easily enters the wound electrode body 3 .

[0079] The average fiber diameter of the fibers constituting the nonwoven fabric is preferably 8 μm to 60 μm. By setting the average fiber diameter of the fibers to 8 μm or more, it is possible to more effectively suppress the intrusion of foreign matter into the wound electrode body 3. In addition, by setting the average fiber diameter of the fibers to 60 μm or less, it is possible to set a structure that allows the electrolyte to easily enter the wound electrode body 3. The average fiber diameter of the fibers is the average value of the diameters of any 10 locations selected on the image measured by SEM.

[0080] Furthermore, when foreign matter having a diameter of 20 μm or more enters the wound electrode body 3, an internal short circuit is likely to occur. 2 This can more effectively suppress foreign matter with a diameter of 20 μm or more from entering wound electrode body 3 . Also, by setting the average fiber diameter of the fibers constituting the nonwoven fabric to 8 μm or more, foreign matter with a diameter of 20 μm or more can more effectively suppress foreign matter with a diameter of 20 μm or more from entering wound electrode body 3 .

[0081] In addition, as the porous base material 30a, in addition to the nonwoven fabric, a porous polymer film made of a polyolefin resin, a fluorine resin, or the like can be used.

[0082] As the adhesive layer 30 b , a member selected from rubber-based adhesives, acrylic-based adhesives, polyethylene-based adhesives, etc., or a mixture thereof is preferable, but the adhesive layer 30 b is not limited thereto.

[0083] like Fig. 7A and Figure 7B As shown, the flat wound electrode body 3 has a flat portion 3a having a substantially uniform thickness and curved portions 3b formed at both ends of the flat portion 3a. The outer surface of the curved portion 3b is curved.

[0084] The length of the flat portion 3a in the direction perpendicular to the winding axis of the wound electrode body 3 (in Fig. 7A and Figure 7B Here, the length L2 of the region where the tape 30 is attached in the wound electrode body 3 is preferably 0.5×L1 or more, and more preferably 0.8×L1 or more.

[0085] In addition, the tape 30 is preferably attached to both outer surfaces of the flat portion 3a of the wound electrode body 3. In this case, one tape 30 can be attached to one outer surface of the flat portion 3a, and the other tape 30 can be attached to the other outer surface of the flat portion 3a. Alternatively, one tape 30 can be attached across one outer surface of the flat portion 3a, the curved portion 3b, and the other outer surface of the flat portion 3a.

[0086] In the above description, an example is described in which the tape 30 is attached to the wound electrode body 3 after the positive electrode current collector 6 is connected to the positive electrode core exposed portion 4 c. However, the tape 30 may be attached to the wound electrode body 3 before the positive electrode current collector 6 is connected to the positive electrode core exposed portion 4 c.

[0087] like Figure 5 As shown in FIG. 1 , it is preferred that the center side end of the tape 30 is arranged at a position further outward than the outer end of the negative electrode plate 5 in the direction in which the winding axis of the wound electrode body 3 extends. That is, it is preferred that when the wound electrode body 3 is viewed in the stacking direction of the positive electrode plate 4, the separator 20, and the negative electrode plate 5 along the flat portion 3a, the negative electrode plate 5 and the tape 30 are arranged so as not to overlap. This can suppress the separator 20 from moving toward the center side ( Figure 5 The tape 30 is bent at the lower middle side to locally generate a thick portion in the flat portion 3a of the wound electrode body 3. Alternatively, the tape 30 and the negative electrode plate 5 may be arranged so as to overlap.

[0088] In addition, it is preferable that one end side of the tape 30 in the width direction is connected to the inclined region of the positive electrode core exposed portion 4 c by the adhesive layer 30 b .

[0089] In addition, the width of the substrate 30a can be set to about 5 mm to 30 mm, for example. However, it is not limited to this. In addition, the width of the adhesive layer 30b can be set to about 2 mm to 10 mm, for example. However, it is not limited to this. The width of the area of ​​the substrate 30a that is provided between the two adhesive layers 30b and where the adhesive layer 30b is not formed can be set to about 1 mm to 25 mm, for example. However, it is not limited to this.

[0090] The tape 30 may be arranged on the outer surface of the exposed portion 4c of the wound positive electrode core body on the side where the positive electrode current collector 6 is not arranged. For example, the tape 30 may be attached to the portion of the outer surface of the exposed portion 4c of the wound positive electrode core body that contacts the anvil or welding head for ultrasonic bonding before ultrasonic bonding. In addition, the tape 30 may be attached to the portion of the outer surface of the exposed portion 4c of the wound positive electrode core body that contacts the anvil or welding head for ultrasonic bonding after ultrasonic bonding.

[0091] <Another Implementation>

[0092] like Figure 8 As shown, the tape 30 may be partially attached to the positive electrode collector 6. If such a structure is adopted, foreign matter attached to the positive electrode collector 6 or burrs formed on the positive electrode collector 6 can be retained on the positive electrode collector 6 by the tape 30.

[0093] Alternatively, after the tape 30 is attached to the separator 20 and the positive electrode core exposed portion 4 c , the positive electrode current collector 6 may be connected to the positive electrode core exposed portion 4 c .

[0094] <Others>

[0095] As for the positive electrode plate, the negative electrode plate, the separator, the electrolyte, and the like, known materials can be used.

[0096] Description of Reference Numerals

[0097] 100, square secondary battery; 200, battery case; 1, square outer body; 2, sealing plate; 3, wound electrode body; 3a, flat portion; 3b, curved portion; 4, positive electrode plate; 4a, positive electrode core; 4b, positive electrode active material layer; 4c, positive electrode core exposed portion; 5, negative electrode plate; 5a, negative electrode core; 5b, negative electrode active material layer; 5c, negative electrode core exposed portion; 6, positive electrode collector; 7, positive electrode terminal; 7a, convex edge; 8, negative electrode collector; 9, negative electrode terminal; 9a, flange; 10, internal insulating member; 11, external insulating member; 12, internal insulating member; 13, external insulating member; 14, insulating sheet; 15, gas discharge valve; 16, electrolyte injection hole; 17, sealing plug; 20, separator; 30, belt; 30a, substrate; 30b, adhesive layer; 80, foreign matter; 90, welding head; 91, anvil.

Claims

1. A secondary battery, The secondary battery has: a first electrode plate having a first electrode active material layer formed on a first electrode core; a second electrode plate having a second electrode active material layer formed on a second electrode core; and A flat wound electrode body is formed by winding the first electrode plate and the second electrode plate with a separator interposed therebetween. in, The wound electrode body has a first electrode core exposed portion wound at one end portion in a direction in which a winding axis of the wound electrode body extends, and has a second electrode core exposed portion wound at the other end portion in a direction in which the winding axis extends, The exposed portion of the wound first electrode core is bundled and connected to the first electrode current collector. A separator is disposed on the outermost surface of the wound electrode body. A tape is attached across the separator disposed on the outermost surface of the wound electrode body and the outermost surface of the exposed portion of the wound first electrode core body. The belt comprises a porous base material and an adhesive layer provided on the base material. The tape has a region where the adhesive layer is not provided on the substrate between a bonding portion between the tape and a separator disposed on the outermost surface of the wound electrode body and a bonding portion between the tape and the outermost surface of the exposed portion of the wound first electrode core.

2. The secondary battery according to claim 1, wherein The porous substrate is a nonwoven fabric.

3. The secondary battery according to claim 2, wherein: The unit area weight of the nonwoven fabric is 40 g / m 2 ~100g / m 2 , The average fiber diameter of the fibers constituting the nonwoven fabric is 8 μm to 60 μm.

4. The secondary battery according to any one of claims 1 to 3, wherein The first electrode plate is a positive electrode plate, and the second electrode plate is a negative electrode plate.

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