JP2003151634A - Nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery with sufficient leakage resistance, good battery characteristic, and easy to manufacture. SOLUTION: This nonaqueous secondary battery contains a battery element constituted by winding or stacking a rechargeable positive electrode, a rechargeable negative electrode, and a separator; an adhesive tape for fixing a part or the whole of the outermost peripheral surface of the battery element; and an electrolyte, and the adhesive tape swells the nonaqueous electrolyte at the degree of swelling of 1 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous secondary battery having excellent resistance to liquid leakage, and more particularly to a lithium ion secondary battery.

[0002]

2. Description of the Related Art In recent years, along with the development of electronic portable equipment, there has been a remarkable development of a battery as a driving source thereof. Among them, the lithium-ion secondary battery has particularly attracted attention because it has a high energy density. At present, generally known lithium-ion secondary batteries include a lithium composite oxide containing a transition metal such as cobalt, nickel, and manganese as a positive electrode active material, and a carbon material containing a graphite or an amorphous material as a negative electrode active material. Using a substance capable of reversibly occluding and releasing lithium such as alloys and amorphous metal oxides, an aprotic organic solvent such as propylene carbonate and ethylene carbonate, and LiPF ₆ , LiB as an electrolytic solution.
An electrolyte such as F ₄ or LiClO ₄ is used, and has a mechanism for charging / discharging by moving lithium ions between the positive and negative electrodes. Since the active material used for both electrodes has a high energy density, the battery can be made smaller and lighter. For this reason, lithium ion secondary batteries have come to be widely used in camera-integrated VTRs or mobile devices such as mobile phones, which are desired to be made smaller and lighter.

Particularly, recently, the outer casing of a lithium ion secondary battery has been changed from a metal can such as stainless steel or aluminum to a laminated film in which a layer of a metal foil such as aluminum and a layer of a polymer sheet are bonded with an adhesive. Sheet-type batteries have been developed that are lighter in weight and thinner than batteries. Laminated films have lower strength than metal cans, and the joints when formed into a bag shape are generally sealed with each other by heat-sealing laminated films or resin, and welding in metal cans Since the strength is lower than that of the joining by the method described above, it is necessary to take sufficient measures against the situation that the outer casing is damaged due to the handling at the time of manufacturing the battery or after handling the battery and the electrolyte leaks. Therefore, a solid electrolyte battery in which a gel-like solid electrolyte containing a plasticizer is arranged between the positive and negative electrodes has been studied.

However, if a large amount of a plasticizer is added to the solid electrolyte, the ionic conductivity is improved, but it becomes difficult to maintain the mechanical strength, so that an internal short circuit may occur due to impact or slight deformation. . As a result, the amount of plasticizer is limited to secure the mechanical strength of the solid electrolyte, and a solid electrolyte with sufficient ionic conductivity cannot be obtained, and the ionic conductivity is lower than that of conventional liquid-type batteries. The current situation is that the rate characteristics and cycle characteristics of batteries are insufficient. Further, in order to provide a solid electrolyte between electrodes in battery production, it is necessary to apply a solid electrolyte containing a plasticizer to the surface of an electrode or a separator, or insert a film of a solid electrolyte formed into a film shape between the electrodes. For this reason, it is necessary to introduce new equipment and increase the number of production steps as compared with the conventional liquid battery, which causes a problem of increasing the manufacturing cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has sufficient liquid leakage resistance and good battery characteristics, and is easy to manufacture and low in cost. A liquid secondary battery and a method for manufacturing the same are provided.

[0006]

Means for Solving the Problems The present inventors have made extensive studies to solve the above problems. As a result, the adhesive tape that fixes a part or the whole of the outermost peripheral surface when the battery element consisting of the positive electrode, the negative electrode, and the separator is wound or laminated without using the solid electrolyte described above may swell the electrolytic solution. It was possible to improve the leakage resistance. Generally, the method of injecting the electrolytic solution into the battery is to put the battery element inside the outer casing,
In order to charge and discharge, a positive electrode and a negative electrode are provided with lead portions capable of conducting current, and then an electrolytic solution is injected into the inside of the outer casing, and then the injected portion is sealed to make a sealed state. The required amount of electrolyte injected into the battery is theoretically the amount that the positive electrode, the negative electrode, and the separator absorb to the saturated state, that is, the total amount of voids in the positive electrode, the negative electrode, and the separator is added to the battery element. It can exert its performance. But,
In this injection method, a part of the injected electrolyte solution accumulates between the battery case and the battery element.Therefore, an excess amount of electrolyte solution is usually applied between the case and the battery element compared to the above required amount. The reality is that it is added.

As a result of detailed examination of the liquid leakage, the present inventors have revealed that the electrolytic solution existing between the battery element and the outer casing is the main cause of the liquid leakage. Therefore, in the present invention, an adhesive tape for fixing a part or the whole area of the outermost peripheral surface when the battery element is wound or laminated swells the electrolytic solution at a high swelling degree of 1 or more, which causes leakage. By absorbing the electrolytic solution existing between the outer package and the outer package, it is possible to improve the liquid leakage resistance without lowering the productivity and the battery performance of the conventional battery element. When the adhesive tape swells the electrolytic solution, it is sufficient that the film and / or the adhesive constituting the adhesive tape can swell. Further, when the battery element is wound or laminated using a conventionally used adhesive tape having no swelling performance, a part or the whole of the outermost peripheral surface is fixed, and the adhesive tape of the present invention is provided on the outer peripheral portion. There is no problem with pasting.

Therefore, the present invention proposes the following secondary battery. A battery element formed by winding or stacking a chargeable / dischargeable positive electrode, a negative electrode, and a separator, an adhesive tape for fixing a part or the entire outermost peripheral surface of the battery element, and a non-aqueous electrolyte solution. The non-aqueous secondary battery according to claim 1, wherein the adhesive tape is capable of swelling the non-aqueous electrolyte with a swelling degree of 1 or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive tape used in the present invention is not particularly limited as long as it can swell the electrolytic solution at a swelling degree of 1 or more. The degree of swelling is shown by the following formula. Swelling degree = mass of electrolytic solution swollen on adhesive tape / mass of adhesive tape before soaking in electrolytic solution The swelling degree is measured by immersing the adhesive tape in the electrolytic solution and keeping it at room temperature (25 ° C) for 3 days. After that, the mass is measured and calculated. When the degree of swelling is less than 1, it is necessary to add a large amount of adhesive tape into the battery in order to absorb the excess electrolytic solution existing between the battery element and the outer package due to the swelling of the adhesive tape. It is practically difficult because the energy is reduced. When the degree of swelling is 1 or more, an improvement in liquid leakage resistance is observed, but when it is 4 or more, it is possible to impart liquid leakage resistance with a small amount of adhesive tape, and thus the energy density per volume of the battery is not reduced.
When the pressure-sensitive adhesive tape swells the electrolytic solution, it is sufficient that either or both of the film and the adhesive constituting the pressure-sensitive adhesive tape can swell. Since the solvent used in the electrolytic solution is generally highly polar, it is easier for the adhesive tape material to swell if it is highly polar.

The material of the film used in the pressure-sensitive adhesive tape of the present invention is not particularly limited, but polymers such as polypropylene, polyethylene, polyethylene terephthalate, polyphenylene sulfide and polytetrafluoroethylene can be used, but these have low polarity and are electrolyzed. It is difficult for the liquid to swell, so it is necessary to select an adhesive with a high swelling property.

On the other hand, as the material of the film having high polarity and high swelling property, (1) unsaturated carboxylic acid ester polymers such as polymethyl acrylate and polymethyl methacrylate, and unsaturated such as polyacrylic acid and polymethacrylic acid Carboxylic acid polymers, vinyl polymers such as polyvinyl acetate and polyvinyl alcohol, polyvinyl fluoride, polyvinylidene fluoride, fluorine-containing polymers such as vinylidene fluoride / propylene hexafluoride copolymer, polyacrylonitrile, acrylonitrile / methyl acrylate copolymer Cyano group-containing polymers such as polymer, polyvinylidene cyanide, etc., polymers obtained by addition polymerization of chlorine-containing polymers such as polyvinyl chloride, polyvinylidene chloride, etc., (2) polyaddition polymers such as polyurethane, polyurea, polycarbonate, ( 3) Poly Ester, polyamide, and the like polymers according polycondensation of polyimide.

Since these polymers have a crosslinked structure, they can be prevented from being dissolved by the electrolytic solution. In order for the polymer to have a crosslinked structure, it can be obtained by adding a crosslinking component together with a monomer and polymerizing. The crosslinking component refers to a monomer having a functional group that gives a self-crosslinking structure during the polymerization during the polymerization.
The molecular weight of the polymer is 10,000 to 500,000.
The range is 0, preferably 100,000 to 1,000,000. If the molecular weight is too low, it is easily dissolved in the electrolytic solution, and if the molecular weight is too high, the viscosity becomes too high and handling becomes difficult.

The adhesive of the pressure-sensitive adhesive tape used in the present invention is not particularly limited as long as it is not substantially dissolved or decomposed by the electrolytic solution. For example, the main polymer is an acrylic resin, vinyl resin, fluorine resin, polyamide. Examples thereof include thermoplastic resins such as amino resins, phenol resins, polyester resins, epoxy resins, thermosetting resins such as isocyanate resins, and rubbers such as polyisobutylene, silicone rubber, nitrile rubber, and neoprene. In particular, acrylic resins having polar groups such as carboxylic acids are preferable from the viewpoint of swelling property, and acrylates such as ethyl acrylate and butyl acrylate and copolymers of carboxylic acids such as acrylic acid and methacrylic acid and the like. Those obtained by cross-linking are particularly preferable.

The thickness and size of the pressure-sensitive adhesive tape are determined in consideration of the degree of swelling of the pressure-sensitive adhesive tape, and when the relationship of the following formula (1) is satisfied, it has excellent battery performance and leakage resistance. . 0.2 ≦ (Wp × SWp) / (We−ρs × Vcal) ≦ 1.0 (1) Wp: Mass of adhesive tape SWp: Swelling degree of adhesive tape We: Total amount of electrolyte injected into battery ρs: Specific gravity of the electrolytic solution Vcal: Total volume of voids in the positive electrode / negative electrode / separator (calculated value) where Vcal is the amount of voids in the positive electrode / negative electrode / separator (calculated value). It is calculated from the difference between the true specific gravity of each material forming the separator and the actually measured specific gravity, and the volume occupied by them.

When the amount of the adhesive tape added is small and (Wp × SWp) / (We−ρs × Vcal) in the above formula (1) is less than 0.2, the amount of the electrolyte absorbed by the adhesive tape is small and liquid leakage occurs. However, the amount of the adhesive tape added is large and (Wp × SWp) / (We−
When ρs × Vcal) exceeds 1.0, the electrolyte solution in the voids in the material such as the positive electrode, the negative electrode, and the separator is also absorbed, and the battery performance such as cycle characteristics is deteriorated. Particularly preferably, (Wp × SWp) / (We-ρs × Vcal) in the formula (1)
Is preferably 0.3 to 0.8 in terms of liquid leakage resistance and battery performance.

[0016] Of the lithium salt of the electrolyte used in the present invention
As a specific example, LiPF₆, LiBF_Four, LiAsF
₆, LiClO_Four, LiSbF₆, LiI, LiBr,
LiCl, LiAlCl_Four, LiHF₂, LiSCN,
CF₃SO₃Li, C_FourF₃SO₃Li, (CF₃SO
₂)₂NLi, (C₂F_FiveSO₂)₂NLi, (CF ₃
SO₂)₃CLi, (C_FourF₉SO₂)₂NLi, or
Include mixtures of these.

The solvent used for the electrolytic solution is as follows. Organic carbonates such as propylene carbonate, butylene carbonate, ethylene carbonate, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, gamma butyl lactone, propiolactone, ethyl butyrate, butyl butyrate, propyl butyrate, ethyl propionate, butyl propionate, etc. The organic ester, diglyme, tetrahydrofuran, diethyl ether, an organic ether such as silicone oil, an organic amine such as pyridine and triethylamine, an organic nitrile such as acetonitrile and propionitrile, or at least a part thereof is contained. The solubility parameter when these aprotic organic solvents are mixed can be determined by the mixing ratio. Among these, propylene carbonate, ethylene carbonate,
Highly polar organic carbonates such as diethyl carbonate, methyl ethyl carbonate and dimethyl carbonate are preferred in terms of battery performance.

As the positive electrode active material of the present invention, all known materials capable of electrochemically occluding and releasing lithium ions can be used, but among them, a material containing lithium is preferable. For example, the general formula Li _X M _Y N _Z O ₂ (M
Are transition metal elements Co, Ni, Fe, Mn, Cr,
At least one metal selected from V, Ti, and Cu, N is at least one metal selected from Al, In, Sn, and B, 0 <X ≦ 1.1, 0.5 <Y ≦ 1.
0, Z ≦ 0.1) is preferable, and further, a lithium oxide composite metal oxide having the general formula Li _X Co _Y N _Z O ₂ (N is
At least one metal selected from Al, In, Sn, and B, 0 <X ≦ 1.1, 0.5 <Y ≦ 1.0, Z ≦
Cobalt lithium salts of 0.1) are more preferable.

A known conductive agent such as activated carbon, various cokes, and non-graphite carbonaceous materials such as carbon black and graphite are added to the positive electrode active material, and a specific conductive agent is added to a specific positive electrode active material. By using a compounded mixture in a specific amount as the positive electrode, the capacity retention rate of room temperature charge / discharge cycle characteristics can be increased. That is, 100 parts by mass of the lithium acid composite metal oxide having an average particle diameter of 1 to 25 μm and the ratio of the average particle diameter to the average particle diameter of the composite metal oxide are 0.2 to
Graphite powder of 40 (preferably having an aspect ratio (minimum projected area / maximum projected area) of 0.2 or less) 2
A mixture of 10 parts by mass and 0.5 to 5 parts by mass of a non-graphitic carbonaceous powder having a ratio of the average particle size to the average particle size of the composite metal oxide of 0.001 to 0.03, or 10 of lithium acid composite metal oxide having an average particle size of 1 to 25 μm
When a mixture of 0 parts by mass and 2 to 10 parts by mass of graphite powder having an average particle size of 3 μm or less (preferably crushed and then graphitized or heat-treated) is used as a positive electrode, room temperature charge / discharge cycle characteristics are obtained. A non-aqueous secondary battery having a high capacity maintenance rate can be obtained.

The positive electrode coating liquid is obtained by mixing a solvent capable of dissolving the positive electrode active material, the conductive agent and the binder. The solid content concentration of the coating liquid is not particularly limited, but is usually 30% by mass to 80% by mass, preferably 40% by mass to 70% by mass. When applied and dried as a positive electrode coating liquid on a substrate, it may be molded together with a collector material if necessary, or alternatively, a collector such as an aluminum foil or a copper foil may be used as a substrate. . Further, as such a coating method, an arbitrary coating device such as a die coater, a reverse roll coater or a comma bar coater can be used.

As the current collector of the positive electrode, Al, Cu, Ni,
A metal foil or net of stainless steel or the like having a thickness of about 8 to 100 μm is used, but it is particularly preferable to use a metal foil or net of Al. As the binder, polyvinylidene fluoride, Teflon (registered trademark), fluororubber, polyethylene, nitrile rubber, polybutadiene, butyl rubber, styrene / butadiene rubber, styrene butadiene latex, polysulfide rubber, nitrocellulose, cyanoethylcellulose, and the above various compositions. Of latex, acrylonitrile, vinyl fluoride, chloroprene, hexafluoropropylene, tetrafluoroethylene, trifluoromonochloroethylene, maleic anhydride, and a copolymer of vinylidene fluoride with one or more of them. Particularly preferable binders include polyvinylidene fluoride, Teflon, and fluororubber.

Next, as the negative electrode active material of the present invention, a material capable of inserting and extracting lithium such as a carbon material, an amorphous alloy, an amorphous metal oxide and an amorphous metal nitride can be used, but a carbon material is particularly preferable. Here, the carbon material refers to a material containing carbon as a main component, graphite and graphitic material, coke, graphite and coke hybrid material, graphitized and carbonized carbon fiber, carbon black, acetylene black, graphitized and Examples include carbonized meso-micro carbon beads, carbon whiskers, carbonized non-graphitizable carbon, and resin fired bodies. As the current collector of the negative electrode, a metal foil or mesh of Cu, Ni, stainless steel or the like having a thickness of about 6 to 100 μm is used.

As the binder, polyvinylidene fluoride, Teflon, fluororubber, polyethylene, nitrile rubber, polybutadiene, butyl rubber, styrene / butadiene rubber, styrene butadiene latex, polysulfide rubber, nitrocellulose, cyanoethylcellulose, and the above various compositions are used. Latex, acrylonitrile, vinyl fluoride,
A copolymer of vinylidene fluoride with one or more of chloroprene, hexafluoropropylene, tetrafluoroethylene, trifluoromonochloroethylene and maleic anhydride is used. Particularly preferred binders include copolymers of vinylidene fluoride with one or more of styrene / butadiene rubber, styrene-butadiene latex, polyvinylidene fluoride and maleic anhydride.

As a processing method using these materials as an electrode, the same method as in the case of the positive electrode can be used. Further, a separator can be provided between the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode. As an example of this separator, a porous sheet or a nonwoven fabric made of a material such as polyethylene, polypropylene or cellulose is used.
In the present invention, the battery form of the secondary battery is not particularly limited, and it can be applied to any form such as a cylinder type, a square type, a thin angle type, a card type, a coin type, and a sheet type. Further, it can be applied to an electrode having any structure such as a wound structure, a laminated structure, and a zigzag structure. Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.

[0025]

Example 1 LiCoO ₂ was synthesized by mixing lithium hydroxide and cobalt hydroxide as a positive electrode active material and then heating in air at a temperature of 800 ° C. for 8 hours. This LiCoO ₂ 10
2.5 parts by mass of graphite having an average particle size of 3 μm and 2.5 parts by mass of non-graphite carbonaceous powder having an average particle size of 0.04 μm were mixed with 0 part by mass to form a compound. To 100 parts by mass of this compound, 4 parts by mass of polyvinylidene fluoride polymer (KF polymer # 1100 manufactured by Kureha Chemical Industry Co., Ltd.) as a binder was added together with N-methyl-2-pyrrolidone, and solid content was 65% after dispersion.
A positive electrode coating liquid of was obtained. The coating solution was applied and dried on both sides of an aluminum foil having a thickness of 15 μm so that the applied amount was 260 ± 3 g / m ^2, and the bulk density of the active material was 2.9 ± 0.3 g with a roll press. The press was performed so that the pressure would be / cm ³ .

On the other hand, as the negative electrode active material, natural graphite: BF-
15SP (made by Chuetsu Graphite Industry Co., Ltd.) 2 parts by mass as a solid content of a latex containing a polymer polymerized with a composition of styrene 50 wt% and butadiene 50 wt% and 1.5 parts by mass of carboxymethyl cellulose per 100 parts by mass. Was mixed in and dissolved in water to obtain a negative electrode coating liquid. Apply this to both sides of 12μm thick copper foil with a coating amount of 93 ± 3g / m
After coating and drying so as to be ² , a roll press was pressed so that the bulk density of the active material was 1.3 ± 0.3 g / cm ³ .

The width of the positive electrode and the negative electrode produced as described above is 5
A tab was welded to each piece cut to 0 mm and a length of 25 cm, and then wound with a cylindrical winding core having a diameter of about 19 mm through a separator of a polyethylene microporous film having a thickness of 25 μm to produce a coil. At the end of winding of this coil, the film material is a copolymer of vinylidene fluoride and propylene hexafluoride with a mixing ratio of 8: 2, and the adhesive is a copolymer of ethyl acrylate and methacrylic acid with a mixing ratio of 9: 1. It was fixed with an adhesive tape having a size of 50 μm, a width of 40 mm, and a length of 25 mm formed of a united body. The swelling degree of this adhesive tape was 3.2 times.

This coil was pressure-molded with a load of 3000 N for 60 seconds by a hot press machine heated to 80 ° C. to form a flat shape, and then the depth was about 3.2 mm, the width was 35 mm, and the height was 5 mm.
The coil was inserted into a laminate film in which a bag-shaped aluminum foil and a polymer sheet were joined, each having a cup-shaped concavo-convex portion with an internal dimension of 5 mm, and an electrolyte solution in which LiBF ₄ was dissolved at 1.5 mol / l (mixed solvent: Ethylene carbonate / gamma butyrolactone (volume ratio 1:
1)) was put in about 2.6 g, and the bag-shaped laminated film was sealed while reducing the pressure to 8000 Pa to prepare a battery as shown in FIG.

This battery was charged at a constant current of 0.5 C for the first cycle in a constant temperature bath at 20 ° C. for 8 hours at a constant potential of 4.2 V (potential between the positive electrode and the negative electrode), and then at 3 C at a constant current of 0.5 C. .0
Charge and discharge characteristics were evaluated by discharging to V potential (here, 1.0
C is a current value capable of discharging the amount of electricity in a fully charged state in 1 hour, and 1.0 C of this battery corresponds to 700 mA. ), The same excellent cycle characteristics as when using a conventionally used pressure-sensitive adhesive tape having no swelling performance (other conditions are the same) were shown.

As an evaluation of liquid leakage resistance, after the first charge / discharge,
Approximately 3 m at two corners of the battery laminate film
After making a hole of m × 3 mm, this battery was placed in a metal container and was subjected to a centrifugal treatment for 30 minutes at a rotation speed of 2000 rpm.
It was a very small amount such as g. The value of the equation (1) is 0.
It was 433.

[0031]

Example 2 Instead of the adhesive tape in Example 1,
The film material is a copolymer of acrylonitrile and methyl acrylate with a mixing ratio of 9: 1, and the adhesive is made of polyisobutylene. Thickness 50 μm, width 40 mm, length 25 m
A battery was prepared and evaluated in the same manner as in Example 1 except that an adhesive tape having a size of m was used. In the evaluation of the leakage resistance of the obtained battery, the mass reduction was 0.013 g as shown in Table 1.
And showed good results. The swelling degree of this adhesive tape is 4.
It was 7 times. The value of the equation (1) was 0.532. The cycle characteristics of the obtained battery also showed good results as in Example 1.

[0032]

Example 3 Instead of the adhesive tape in Example 1,
Except for using an adhesive tape having a thickness of 50 μm, a width of 40 mm, and a length of 25 mm, the film material is polyurethane, and the adhesive is a copolymer of ethyl acrylate and methacrylic acid with a mixing ratio of 9: 1. A battery was prepared and evaluated in the same manner as in Example 1. In the evaluation of the liquid leakage resistance of the obtained battery, the mass reduction was 0.010 g, which is a good result as shown in Table 1. The swelling degree of this adhesive tape was 5.5 times. The value of the formula (1) was 0.733. The cycle characteristics of the obtained battery also showed good results as in Example 1.

[0033]

Example 4 Instead of the adhesive tape in Example 1,
Except for using an adhesive tape having a thickness of 50 μm, a width of 40 mm, and a length of 35 mm, the film material is polyethylene, and the adhesive is a copolymer of ethyl acrylate and methacrylic acid with a mixing ratio of 9: 1. A battery was prepared and evaluated in the same manner as in Example 1. In the evaluation of the leakage resistance of the obtained battery, the mass reduction was 0.092 g, which is a good result as shown in Table 1. The swelling degree of this adhesive tape was 1.4 times. The value of the formula (1) was 0.282. The cycle characteristics of the obtained battery also showed good results as in Example 1.

[0034]

Comparative Example 1 Instead of the adhesive tape in Example 1,
The film material is polyethylene and the adhesive is polyisobutylene, thickness 50 μm, width 40 mm, length 3
A battery was prepared and evaluated in the same manner as in Example 1 except that an adhesive tape having a size of 5 mm was used. In the evaluation of the leakage resistance of the obtained battery, the mass reduction was 0.47 as shown in Table 1.
It was as large as 5 g, showing a result that the liquid leakage resistance was not sufficient. The swelling degree of this adhesive tape was 0.3 times. The value of the above formula (1) was 0.033. On the other hand, the cycle characteristics of the obtained battery showed good results as in Example 1.

[0035]

Comparative Example 2 Instead of the adhesive tape in Example 1,
The film material is Teflon, the adhesive is polyisobutylene, thickness 50μm, width 40mm, length 35m
A battery was prepared and evaluated in the same manner as in Example 1 except that an adhesive tape having a size of m was used. In the evaluation of the leakage resistance of the obtained battery, the mass reduction was 0.489 g as shown in Table 1.
The results showed that the liquid leakage resistance was not sufficient. The swelling degree of this adhesive tape was 0.1 times. The value of the formula (1) was 0.013. On the other hand, the cycle characteristics of the obtained battery showed good results as in Example 1.

[0036]

[Table 1]

[0037]

EFFECTS OF THE INVENTION According to the present invention, when the battery element comprising the positive electrode, the negative electrode and the separator is wound or laminated by using the adhesive tape which swells the electrolytic solution with the swelling degree of 1 or more as described above. By fixing part or all of the outer peripheral surface, it is possible to realize a non-aqueous electrolyte secondary battery having good leakage resistance and cycle characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing a battery prepared by inserting a positive electrode / negative electrode coil into a laminate film having a cup-shaped concavo-convex portion, filling an electrolytic solution, and sealing under a reduced pressure.

[Explanation of symbols]

1 battery 2 Laminated film 3 Positive electrode tab 4 Negative tab

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Claims (2)

[Claims] 1. A battery element formed by winding or stacking a chargeable / dischargeable positive electrode, a negative electrode, and a separator, an adhesive tape for fixing a part or all of the outermost peripheral surface of the battery element, and a non-aqueous material. A non-aqueous secondary battery comprising an electrolytic solution, wherein the adhesive tape is capable of swelling the non-aqueous electrolytic solution with a swelling degree of 1 or more. 2. The non-aqueous secondary battery according to claim 1, wherein the amount of the adhesive tape satisfies the following formula (1). 0.2 ≦ (Wp × SWp) / (We−ρs × Vcal) ≦ 1.0 (1) Wp: Mass of adhesive tape SWp: Swelling degree of adhesive tape We: Total amount of electrolyte injected into battery ρs: Specific gravity of electrolyte Vcal: Total volume of voids in the positive electrode / negative electrode / separator (calculated value)