JPH11162252A - High polymer electrolyte and nonaqueous electrolyte battery provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent short-circuit even through winding, easily fabricate a cylindrical or rectangular battery, and improve mechanical strength and efficient discharge performance by integrally forming a polymer and a nonwoven cloth swelled or wetted by an electrolyte. SOLUTION: A polymer with its mechanical strength swelled and wetted by an electrolyte is formed integrally with nonwoven polymer swelled or wetted by an electrolyte. In this case, the non-woven cloth serves to reinforce endurance to tension from all ways from a polymeric membrane swelled or wetted by an electrolyte, and if this polymeric electrolyte is wound between positive and negative electrodes, an electrode group can be fabricated without membrane cracks and breaks. For example, as a polymer having properties swelled or wetted by an electrolyte, polyphenyl vinylidene powder is decomposed in n- methyl-2-porolydone-(NMP), non-woven cloth consisting mainly of polypropylene is immersed in this solution, and is immersed in water, and NMP is washed out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer electrolyte and a non-aqueous electrolyte battery provided with the same.

[0002]

2. Description of the Related Art In recent years, with the development of electronic devices, the appearance of new high-performance batteries is expected. As typical batteries, there are a lithium battery and a lithium ion battery (hereinafter collectively referred to as a lithium-based battery). In lithium-based batteries, most of the amount of lithium ions involved in the electrode reaction in the charge / discharge reaction is not lithium ions dissolved in the electrolyte, but lithium ions released from the electrode active material move in the electrolyte. As a result, the lithium ion travels a long distance. In addition, while the transport numbers of protons and hydroxide ions in the electrolytic solution of the aqueous battery show values close to 1, the transport numbers of lithium ions in the electrolytic solution of the lithium battery at room temperature are usually 0.5. In the following, the moving speed of ions in the electrolyte is governed by the concentration diffusion of ions. Further, since the organic electrolyte has a higher viscosity than the aqueous solution, the diffusion speed of ions is low. Therefore, the lithium-based battery has a problem that the charge / discharge performance at a high rate is inferior to that of the aqueous solution-based battery.

As one means for solving these problems, lithium ions can pass not only in the electrolyte inside the pores of the polymer membrane but also in the polymer electrolyte itself. A porous polymer electrolyte has been proposed that enables charge and discharge at a higher rate than a battery.

[0004]

However, the porous polymer electrolyte membrane has a low mechanical strength, complicates the winding process, and is liable to cause a short circuit due to the winding. There is a problem that it is difficult to manufacture a type battery. Therefore, the present invention has been made in view of the above-mentioned problems, and a polymer having a mechanical strength that is unlikely to cause a short circuit even when wound and that can easily produce a cylindrical or square battery. Provide electrolyte,
It is still another object of the present invention to provide a non-aqueous electrolyte battery that is not inferior to conventional batteries in high-rate discharge performance.

[0005]

According to a first aspect of the present invention, there is provided a polymer electrolyte comprising a polymer which swells or wets with an electrolyte, and a nonwoven fabric. A second invention is characterized in that the polymer and the nonwoven fabric are integrally formed. A third invention is characterized in that the polymer is formed on all or a part of the pores of the nonwoven fabric, or on all or a part of the pores of the nonwoven fabric, and on one surface or both surfaces of the nonwoven fabric. A fourth invention is characterized in that the main components of the polymer and the nonwoven fabric which swell or wet with the electrolyte are made of the same substance. The fifth invention is
The polymer swelled or wetted by the electrolytic solution has lithium ion conductivity and has pores. According to a sixth aspect of the present invention, the polymer swelled or wetted by the electrolytic solution is selected from polyvinylidene fluoride, polyvinyl chloride, and polyacrylonitrile, or two or more of these, or one or more of these. It is characterized by including a copolymer. The seventh invention is characterized in that the polymer which swells or wets with the electrolytic solution contains two or more kinds of copolymers, and contains polyvinylidene fluoride as a subcomponent thereof. The invention is characterized by combining these inventions. In addition, the eighth
Non-aqueous electrolyte battery according to the invention of the first, second, third, fourth,
It is characterized by comprising the polymer electrolyte of the invention of 5, 6, or 7, or an invention of a combination thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In a polymer electrolyte according to the present invention, a polymer having low mechanical strength and swelling or wetting by an electrolytic solution is present together with a nonwoven fabric having high mechanical strength. That is, the polymer electrolyte is wound between the positive electrode and the negative electrode so as to function as a reinforcing material for the nonwoven fabric to withstand the pulling of the polymer film swollen or wetted by the electrolyte from all directions. In the case of, the electrode group can be produced without cracking or breaking of the film,
Thus, a cylindrical or prismatic battery can be easily manufactured.

Further, the polymer electrolyte according to the present invention has a high mechanical strength even in the thickness direction of the membrane because it has a non-woven fabric, so that it is compared with a conventional porous polymer electrolyte membrane alone. As a result, the occurrence of a short circuit when winding is performed can be significantly reduced.

Further, the polymer electrolyte of the present invention contains a polymer which swells or wets with the electrolytic solution, so that the polymer electrolyte is charged at a higher rate than a liquid nonaqueous electrolyte battery (using a separator). Discharge is possible. When the nonwoven fabric is made of the same material as the polymer, the nonwoven fabric also swells or wets with the electrolytic solution, so that ions can move therethrough.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments.

(Example 1) A polymer electrolyte membrane was produced as follows. 12 g of PVdF powder having an average molecular weight of 60,000 and having a property of swelling or wetting by the electrolytic solution was dissolved in 88 g of n-methyl-2-pyrrolidone (hereinafter referred to as NMP). Next, a thickness of 31 μm mainly composed of polypropylene (hereinafter referred to as PP).
m, a nonwoven fabric having a basis weight of 11 g / m ² was immersed in this solution in order to make the solution exist in the mesh of the nonwoven fabric and on the front and back sides. Further, this was immersed in water to wash out the NMP, thereby producing a polymer electrolyte membrane having a porosity of 60% and a thickness of 40 μm.

Next, lithium cobaltate (LiCoO)
₂ ) 70 wt%, acetylene black 6 wt%, polyvinylidene fluoride (hereinafter referred to as PVdF) 9 wt%
%, NMP 15 wt% mixed to a thickness of 20μ
m on an aluminum foil, dried at 150 ° C.
The MP was evaporated. After the above operation was performed on both surfaces of the aluminum foil, it was pressed to obtain a positive electrode plate. The thickness of the positive electrode plate after pressing was 170 μm.

In addition, graphite 81 wt%, PVdF
A mixture of 9 wt% and NMP 10 wt% has a thickness of 1
It was applied on a 4 μm copper foil and dried at 150 ° C. to evaporate NMP. After performing the above operation on both surfaces of the copper foil, it was pressed to obtain a negative electrode plate. The thickness of the negative electrode plate after pressing was 190 μm.

The above-prepared positive electrode plate and negative electrode plate are wound with the above-mentioned polymer electrolyte membrane interposed therebetween, and the length is 1 mm.
The battery was inserted into a cylindrical stainless steel case having a diameter of 80 mm and a diameter of 6.5 mm to assemble a cylindrical battery. Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 1: 1 inside the battery, and 1 mol
3.0 g of an electrolytic solution in which 1 / l of LiPF ₆ was dissolved was injected by vacuum injection, and the polymer electrolyte membrane was swollen by the electrolyte. Thus, the design capacity is 1400 mA
h, 100 batteries (A) of Example 1 of the present invention were manufactured.

Example 2 In Example 2, a nonwoven fabric was made of P
Instead of those having P as the main component, an average molecular weight of 60,0
Example 1 except that a polymer electrolyte membrane having a porosity of 60% and a thickness of 40 μm was manufactured using a PVdF having a thickness of 30 μm and a basis weight of 10 g / m ^2. Design capacity 140 having the same configuration as
0 mAh of the battery (B) of Example 1 according to the present invention
Made individually.

(Comparative Example 1) As Comparative Example 1, a solution prepared by dissolving 12 g of PVdF powder having an average molecular weight of 60,000 in 88 g of NMP was immersed in water to wash out the NMP, to obtain a porosity of 60% and a thickness of 40 μm. Except for using a polymer electrolyte membrane without a nonwoven fabric, 100 conventionally known batteries (a) having the same configuration as in Example 1 and having a design capacity of 1400 mAh were manufactured.

(Result 1) Table 1 shows that these batteries (A),
4 is a table showing the state of occurrence of defects at the time of manufacturing the batteries of (B) and (a). From the table, when the batteries (A) and (B) according to the present invention are wound using a machine to form an electrode group, the short-circuit occurrence rate during assembly is lower than that of the conventionally known battery (a). It has dropped significantly.

Next, using these batteries (A), (B) and (a), the batteries were charged at 0 ° C. with a current of 0.2 CA to 4.1 V, and subsequently with a constant voltage of 4.1 V. After charging for 2 hours, the battery was discharged to 2.5 V at a current of 1 CA.

FIG. 1 shows the battery (A) of Example 1 and Example 2
7 is a comparison of the discharge characteristics in the above test when using the battery (B) of Comparative Example 1 and the battery (A) of Comparative Example 1.
From the figure, it is understood that the batteries (A) and (B) according to the present invention exhibit discharge characteristics comparable to those of the conventionally known battery (a).

Therefore, the batteries (A) and (B) of the present invention
It can be understood that, compared to the conventionally known battery (a), the workability of winding the electrode group and the like is improved, and the battery exhibits the same discharge characteristics. In the case of a flat wound electrode, since it is bent almost 180 degrees at the beginning of winding, a short circuit is likely to occur at the beginning of winding. However, it is understood that the present invention also has an effect that a short circuit at the beginning of winding is less likely to occur. Was.

Example 3 A polymer electrolyte membrane was prepared as follows. 88 g of n was obtained by mixing 12 g of polyacrylonitrile (hereinafter referred to as PAN) powder having an average molecular weight of 60,000 and having a property of swelling or wetting with an electrolytic solution.
-Methyl-2-pyrrolidone (hereinafter referred to as NMP). Next, a 30 μm-thick sheet made from PAN having an average molecular weight of 60,000 and a basis weight of 10 g /
In order to make this solution exist in the mesh and the front and back of the non-woven fabric of m ² , it was immersed in the solution. This was further immersed in water to wash out the NMP, thereby obtaining a polymer electrolyte membrane having a porosity of 60% and a thickness of 40 μm.

Next, lithium cobaltate (LiCo
O ₂ ) 70 wt%, acetylene black 6 wt%, polyvinylidene fluoride (PVdF) 9 wt%, n-methyl-
A mixture of 15 wt% of 2-pyrrolidone (NMP) was applied on an aluminum foil having a thickness of 20 μm,
Dry at <RTIgt; C </ RTI> to evaporate the NMP. After the above operation was performed on both surfaces of the aluminum foil, it was pressed to obtain a positive electrode plate. The thickness of the positive electrode plate after pressing was 170 μm.

Further, graphite 81 wt%, PVdF
A mixture of 9 wt% and NMP 10 wt% has a thickness of 1
It was applied on a 4 μm copper foil and dried at 150 ° C. to evaporate NMP. After performing the above operation on both surfaces of the copper foil, it was pressed to obtain a negative electrode plate. The thickness of the negative electrode plate after pressing was 190 μm.

A polymer electrolyte membrane is interposed between the positive electrode plate and the negative electrode plate prepared as described above, and is wound to a length of 180 m.
m, and inserted into a cylindrical stainless steel case having a diameter of 6.5 mm to assemble a cylindrical battery. Inside the battery, ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 1: 1 and mixed at 1 mol / l.
The electrolyte 3.0g which was dissolved LiPF ₆ in addition by vacuum infusion, to swell the polymer electrolyte membrane by the electrolyte. Thus, a battery (C) of Example 3 according to the present invention having a nominal capacity of 1400 mAh was manufactured.

Example 4 As Example 4, a nonwoven fabric was made of P
A polymer electrolyte membrane having a porosity of 60% and a thickness of 40 μm is used by using a polypropylene (PP) having a thickness of 31 μm and a basis weight of 11 g / m ² instead of the one containing AN as a main component. A battery (D) of Example 1 according to the present invention having a nominal capacity of 1400 mAh and having the same configuration as that of Example 3 described above except that it was manufactured was manufactured.

(Comparative Example 2) As Comparative Example 1, a solution of 12 g of PAN powder having an average molecular weight of 60,000 dissolved in 88 g of NMP was immersed in water to wash out the NMP, thereby obtaining a porosity of 60% and a thickness of 40 μm. A conventionally known battery (E) having a nominal capacity of 1400 mAh and having the same configuration as in Example 1 except that a polymer electrolyte membrane having no nonwoven fabric was used was manufactured.

(Result 2) Table 2 shows that these batteries (C),
It is a table | surface which shows the failure occurrence state at the time of battery manufacture of (D) and (E). As can be seen from the table, the batteries (C) and (D) according to the present invention have a significantly higher short-circuit occurrence rate during assembly as compared with the known battery (E) when the electrode group is manufactured by winding using a machine. Has declined.

Next, using these batteries (C), (D) and (E), the batteries were charged at 0 ° C. with a current of 0.2 CA to 4.1 V, and subsequently charged at a constant voltage of 4.1 V for 2 hours. After that, the battery was discharged to 2.5 V at a current of 1 CA.

FIG. 3 shows the battery (C) of Example 3 and Example 4
9 is a comparison of the discharge characteristics in the above test when the battery (D) of Comparative Example 2 and the battery (E) of Comparative Example 2 were used.
From these figures, it can be seen that the batteries (C) and (D) according to the present invention
Was found to exhibit discharge characteristics comparable to those of the known battery (E).

Example 5 As Example 5, PAN was used as a polymer having a property of swelling or wetting by an electrolytic solution.
Is a non-woven fabric having a thickness of 30 μm and a basis weight of 10 g / m ² made of PVC having an average molecular weight of 60,000 using polyvinyl chloride having an average molecular weight of 60,000 (hereinafter, referred to as PVC). Except that the nominal capacity 14 is the same as that of the third embodiment.
A battery (F) of Example 5 according to the present invention having a capacity of 00 mAh was manufactured.

Example 6 In Example 6, PVC was used as a polymer having a property of swelling or wetting by an electrolytic solution.
Example 5 except that a polymer electrolyte membrane having a porosity of 60% was manufactured so as to have a thickness of 40 μm using a copolymer consisting of PVC having an average molecular weight of 60,000 and polyvinylidene fluoride instead of A battery (G) of Example 6 according to the present invention having a nominal capacity of 1400 mAh and the same configuration as that of Example 6 was produced.

Example 7 As Example 7, a nonwoven fabric was made of P
A polymer electrolyte membrane having a porosity of 60% and a thickness of 40 μm is used by using a polypropylene (PP) having a thickness of 31 μm and a basis weight of 11 g / m ² instead of the one containing VC as a main component. A battery (H) of Example 5 according to the present invention having a nominal capacity of 1400 mAh and having the same configuration as that of Example 5 described above was manufactured except that it was manufactured.

Comparative Example 3 As Comparative Example 3, a conventionally known battery (I) having a nominal capacity of 1400 mAh and having the same configuration as that of Comparative Example 2 except that PVC was used instead of PAN was manufactured. .

(Result 3) Table 3 shows that these batteries (F),
5 is a table showing the state of occurrence of defects at the time of manufacturing the batteries of (G), (H) and (I). From the table, the battery (F) according to the present invention,
In (G) and (H), it was found that when the electrode group was produced by winding by a machine, the short-circuit occurrence rate during assembly was extremely low as compared with the known battery (I). In addition, also in the discharge performance, similar to the result 2, compared with the known battery (I),
It was found that the battery exhibited discharge characteristics comparable to those of the prior art.

In the above embodiment, as a method for producing a microporous polymer membrane, NMP is removed by immersing a solution of a polymer in NMP in water. The material is not limited to NMP, and any material capable of dissolving a polymer may be used. For example, carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and ethers such as dimethyl ether and diethyl ether are exemplified.

Further, the liquid in which the solution in which the polymer is dissolved is immersed is not limited to water, and is not capable of dissolving the polymer and compatible with the solvent in which the polymer is dissolved. Should be fine. For example, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol, hydrocarbons such as hexane, benzene, toluene and xylene, methyl chloride, halogenated carbon such as dichloromethane, carbon tetrachloride, dichloroethane and trichloroethane, phenol and the like Phenols,
Examples include ethers such as diethyl ether, ketones such as acetone, fatty acids such as formic acid and acetic acid, esters such as methyl formate, ethyl formate, methyl acetate and ethyl acetate, and nitrogen compounds such as nitromethane, nitroethane, nitrobenzene and acetonitrile. Is done.

When the solvent is removed from the polymer solution using the polymer of such a combination, a solvent for dissolving the polymer, and a liquid for immersing the solution in which the polymer is dissolved, the solvent removed The portion where was present becomes a hole, whereby a microporous polymer membrane can be manufactured.

As a method for producing a porous polymer for producing a porous polymer electrolyte, in addition to the above-described methods, a stretching method,
A method for removing fine particles from a polymer to which fine particles have been added, a method for removing a solidified polymer by cooling a high-temperature polymer solution, and a fine needle made of stainless steel after a nonporous polymer film is manufactured. We tried a method of physically drilling through holes using. Among these, batteries manufactured by a method using fine needles of stainless steel exhibited excellent charge / discharge characteristics as in the case of using a wet method, but sufficient porosity was not obtained by other methods. Was.

The polymer used for the porous polymer electrolyte may be polyvinyl chloride (PVD) in addition to the above-mentioned PVdF.
C), using polyacrylonitrile (PAN), polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polymethyl acrylate, polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinyl pyrrolidone, polyethylene imine, polybutadiene, polystyrene and polyisoprene. An attempt was made to produce a porous polymer electrolyte and a battery using the same. When PVdF, PVC and PAN were used, the charge / discharge characteristics, particularly the high rate discharge characteristics, were excellent. In addition, PAN is more preferable because PVdF and PVC have considerably large swellability. Furthermore, since PAN has excellent heat resistance and flame retardancy, it does not impair battery performance even when used at high temperatures.

In the above embodiment, polyvinylidene fluoride is used as the polymer which swells or wets with the electrolytic solution. However, the polymer is not limited to polyvinylidene fluoride, and polyethers such as polyvinyl chloride, polyethylene oxide and polypropylene oxide are used. , Polyacrylonitrile, polyvinylidene fluoride, polyvinylidene chloride, polymethyl methacrylate, polymethyl acrylate, polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinyl pyrrolidone, polyethylene imine, polybutadiene, polystyrene, polyisoprene, or derivatives thereof. May be used alone or as a mixture. Further, a polymer obtained by copolymerizing various monomers constituting the above polymer may be used.

In the above embodiment, a mixed solution of EC and DEC is used as the electrolytic solution contained in the polymer. However, the present invention is not limited to this, and ethylene carbonate, propylene carbonate, dimethyl Carbonate, diethyl carbonate, γ-butyrolactone, sulfolane, dimethyl sulfoxide, acetonitrile, dimethylformamide, dimethylacetamide, 1,
A polar solvent such as 2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dioxolan or methyl acetate, or a mixture thereof may be used.

In addition, in the above-described embodiment, LiPF ₆ is used as the lithium salt to be contained in the electrolytic solution. In addition, LiBF ₄ , LiAsF ₆ , LiCl
O ₄ , LiSCN, LiI, LiCF ₃ SO ₃ , LiC
l, LiBr, LiCF ₃ CO ₂ or Li (CF ₃ S
A lithium salt such as O ₂ ) ₂ N or a mixture thereof may be used.

In the above embodiment, LiCoO ₂ was used as the positive electrode active material, but the present invention is not limited to this. In addition, as the inorganic compound, the composition formula Li
_x MO ₂ or Li _y M ₂ O ₄ (where M is a transition metal, 0
≦ x ≦ 1, 0 ≦ y ≦ 2), a complex oxide having tunnel-like vacancies, or a metal chalcogenide having a layered structure can be used. As a specific example, L
iCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O
₄ , MnO ₂ , FeO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , T
iS _{2 and the} like. Examples of the organic compound include a conductive polymer such as polyaniline. In addition, the above-mentioned various active materials may be mixed and used irrespective of an inorganic compound or an organic compound.

In the above embodiment, graphite is used as the negative electrode active material.
alloys of one or more of 1, Si, Pb, Sn, Zn or Cd with lithium, transition metal composite oxides such as LiFe ₂ O ₃ , transition metal oxides such as WO ₂ , MoO ₂ , graphite, A carbonaceous material such as carbon, lithium nitride such as Li ₅ (Li ₃ N), or a metallic lithium foil, or a mixture thereof may be used.

[0044]

As described above, according to the present invention, a polymer electrolyte comprising a polymer which swells or wets with an electrolyte and a nonwoven fabric has an improved mechanical strength of a membrane and a conventional porous material. Compared with the polymer electrolyte membrane, the membrane can be wound by a machine without cracking or breaking, and a cylindrical or prismatic battery can be easily manufactured. In addition, since the polymer electrolyte of the present invention has a nonwoven fabric, the mechanical strength is high even in the thickness direction of the membrane, and short-circuiting occurs when winding is performed as compared with the conventional case. Can be suppressed.

Furthermore, since the polymer electrolyte of the present invention contains a polymer that swells or wets with the electrolyte, it can be charged and discharged at a higher rate than a liquid nonaqueous electrolyte battery. In addition, when the nonwoven fabric is made of the same material as the polymer that swells or wets with the electrolytic solution, the nonwoven fabric also swells or wets with the electrolytic solution, so that ions can move in the nonwoven fabric and the battery performance is significantly improved. be able to.

[Brief description of the drawings]

FIG. 1 shows a battery (A) according to the present invention in Example 1, a battery (B) according to the present invention in Example 2, and Comparative Example 1
FIG. 5 is a view showing a discharge curve after leaving the battery (a).

FIG. 2 is a cross-sectional view of a non-aqueous electrolyte secondary battery having flat-wound electrodes.

FIG. 3 shows a battery (C) according to the present invention in Example 3, a battery (D) according to the present invention in Example 4, and Comparative Example 2
FIG. 5 is a view showing a discharge curve after leaving the battery (E).

[Description of Signs] 1 Rectangular nonaqueous electrolyte secondary battery 2 Flat wound electrode 3 Case 4 Lid 5 Safety valve 6 Positive electrode terminal 7 Separator (polymer solid electrolyte) 8 Positive electrode 9 Negative electrode

[Table 1]

[Table 2]

[Table 3]

Claims (8)

[Claims] 1. A polymer electrolyte comprising a polymer which swells or wets with an electrolyte and a nonwoven fabric. 2. The polymer electrolyte according to claim 1, wherein the polymer and the nonwoven fabric are integrally formed. 3. The non-woven fabric according to claim 2, wherein the polymer is formed on all or a part of the holes of the non-woven fabric, or on all or a part of the holes of the non-woven fabric, and on one or both surfaces of the non-woven fabric.
The polymer electrolyte according to the above. 4. The polymer electrolyte according to claim 1, wherein the main components of the polymer and the nonwoven fabric which swell or wet with the electrolytic solution are composed of the same substance. 5. The polymer according to claim 1, 2, 3 or 4, wherein the polymer which swells or wets with the electrolytic solution has lithium ion conductivity and has pores. Molecular electrolyte. 6. A polymer which swells or wets with an electrolyte solution is selected from polyvinylidene fluoride, polyvinyl chloride, and polyacrylonitrile, or two or more thereof, or a copolymer of one or more thereof. 6. The method according to claim 1, further comprising:
The polymer electrolyte according to the above. 7. The polymer according to claim 1, wherein the polymer swelled or wetted by the electrolyte contains at least two kinds of copolymers, and contains polyvinylidene fluoride as an auxiliary component. 7. The polymer electrolyte according to 5 or 6. 8. A non-aqueous electrolyte battery comprising the polymer electrolyte according to claim 1, 2, 3, 4, 5, 6, or 7.