JPH09139200A - Manufacture of non-aqueous electrolyte battery and positive pole component member for non-aqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stability and reliability for discharge property of minute current or long-duration storage. SOLUTION: In a non-aqueous electrolyte battery provided with a negative pole component members 2d and 3, positive pole component members 1, 2a, and 2b, and a non-aqueous electrolyte 2e as battery power generation elements, the faces of the positive pole component members 1, 2a, and 2b in contact with at least non-aqueous electrolyte 2e is covered with a film 5 of a pyridine high polymer molecule compound. It is desirable that the pyridine high polymer molecule compound is at least one type of poly-2-vynil pyridine hydrochloride and poly-4-vynil pyridine hydrochloride, and that the viscosity average molecule weight is 21000 or more. Pyridine high polymer molecule compound solution is applied on a face in contact with the non-aqueous electrolyte, and an adsorption layer is formed by applying heating treatment at a 50 to 100 deg.C if required.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery and a method for manufacturing a positive electrode constituent member for a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art Recently, as a non-aqueous electrolyte battery, a negative electrode using a light metal such as lithium or sodium as a negative electrode active material, a positive electrode using a metal oxide, sulfide or halide as a positive electrode active material, and a non-aqueous electrolyte. Batteries equipped with a liquid as a battery power generation element have been attracting attention as batteries having high voltage, high energy density and long-term reliability. For example, lithium-ion batteries, which use manganese dioxide (MnO ₂ ), fluorocarbon (CF ₂ ) _n , thionyl chloride (SOCl ₂ ) as a positive electrode active material, are often used as calculators, clock power supplies and memory backup batteries. There is. That is, a non-aqueous electrolyte battery such as a lithium-ion battery has a smaller self-discharge than a silver battery or an alkaline battery and thus can be used for a long period of time. Therefore, it is used as a power source for the calculator, the clock and the like.
In addition, this non-aqueous electrolyte battery is required to have stable discharge characteristics over a long period of time by a minute current in response to the development and development of driven electronic devices. here,
The minute current is at most several μA, but in order to secure stable discharge characteristics, high reliability of the battery itself is important.

On the other hand, even in the case of a secondary battery used as an operating power source by being incorporated in various equipment systems such as a mobile phone and a portable image pickup device, it is possible to reduce the size and weight of the mobile phone and the portable image pickup device. Along with this, a lithium ion battery having a high energy density is required as a power source. In this type of non-aqueous electrolyte battery, for example, LiCl0 ₄ , LiBF ₄ , LiAsF ₆ is used as an electrolytic solution in an organic solvent such as propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone, and tetrahydrofuran. An organic electrolytic solution (non-aqueous electrolytic solution) obtained by dissolving a lithium salt such as is used. Further, as a positive electrode constituent member such as a positive electrode supporting a positive electrode active material, a positive electrode can also serving as a positive electrode terminal, and a positive electrode current collector, austenitic stainless steel having a nickel content of 3 to 20% by weight is generally used. ing.

[0004]

However, in the case of the non-aqueous electrolyte battery having the above-mentioned structure, the internal resistance of the battery increases during storage of the battery, and the required performance cannot be sufficiently exhibited, and Inconveniences such as loss of function are often observed. That is, during storage of the non-aqueous electrolyte battery, austenitic stainless steel or the like forming the positive electrode constituent member is eluted into the non-aqueous electrolyte solution, and this is deposited on the negative electrode to form a passivation film. The resistance may increase and the battery life may be shortened. In an extreme case, the positive electrode structural member may be corroded and perforated, which may cause structural damage. Then, such a phenomenon depends on the nickel content in the austenitic stainless steel as a constituent material, and becomes more remarkable as the nickel content increases.

To solve the problem when the positive electrode constituent member is made of austenitic stainless steel, it has been attempted to make it of ferritic stainless steel containing almost no nickel and less susceptible to cracking under stress. For example
When stored at a high temperature of 60 to 80 ° C for a long period of time, the phenomenon of elution into the non-aqueous electrolyte is observed as in the case of austenitic stainless steel.

[0006] As described above, the conventional non-aqueous electrolyte primary battery and non-aqueous electrolyte secondary battery are concerned about problems such as stable discharge of minute current or deterioration of battery function during long-term storage. Therefore, it cannot be said that it is practically sufficiently satisfactory in terms of reliability.

The present invention has been made in view of such circumstances, and has a stable discharge of a minute current and a good stability for long-term storage, and functions as a highly reliable non-aqueous electrolyte battery. And a method capable of manufacturing a positive electrode structural member for a non-aqueous electrolyte battery exhibiting a highly reliable battery function.

[0008]

According to a first aspect of the present invention, there is provided a non-aqueous electrolyte battery including a negative electrode constituent member, a positive electrode constituent member, and a non-aqueous electrolyte solution as a battery power generating element, It is a non-aqueous electrolyte battery characterized in that at least a surface of a positive electrode constituent member in contact with the non-aqueous electrolyte is coated with a film of a pyridine polymer compound.

According to a second aspect of the present invention, in the non-aqueous electrolyte battery according to the first aspect, the pyridine polymer compound is poly-
It is characterized in that it is at least one of 2-vinylpyridine hydrochloride and poly-4-vinylpyridine hydrochloride.

According to a third aspect of the present invention, in the non-aqueous electrolyte battery according to the first or second aspect, the pyridine polymer compound has a viscosity average molecular weight of 21,000 or more, such as poly-2-vinylpyridine hydrochloride and poly-. It is characterized in that it is at least one of 4-vinylpyridine hydrochloride.

According to a fourth aspect of the present invention, in the method for producing a positive electrode constituent member for a non-aqueous electrolyte battery, a pyridine polymer compound solution is applied to at least a surface of the positive electrode constituent member that is in contact with the non-aqueous electrolyte solution and heated. A method for manufacturing a positive electrode constituent member for a non-aqueous electrolyte battery, which comprises subjecting the material to a treatment to form an adsorption layer made of a pyridine-based polymer compound. Claim 5
In the method for producing a positive electrode structural member for a non-aqueous electrolyte battery according to claim 4, the heat treatment temperature is 50 to 100 ° C.

The present invention was made based on the results of the following tests and studies. That is, among positive electrode constituent members such as a positive electrode structure that supports a positive electrode active material, a positive electrode can that also serves as a positive electrode terminal, and a positive electrode current collector, at least the surface of the positive electrode constituent member that is in contact with the non-aqueous electrolyte solution should have a pyridine polymer solution When a pyridine-based polymer compound film is coated by applying heat treatment at a temperature of 50 to 100 ° C., the coating film is not dissolved or damaged by the non-aqueous electrolyte solution, Based on this finding, the inventors of the present invention have achieved the present invention based on this finding. Further, in addition, as long as the positive electrode constituent member is coated with a film (adsorption layer) made of a pyridine-based polymer compound on the surface of the region in contact with the non-aqueous electrolyte,
Focusing on the fact that this coating layer significantly improves the corrosion resistance to non-aqueous electrolyte (improves the corrosion resistance), exhibits stable discharge characteristics over a long period of time, and functions as a highly reliable non-aqueous electrolyte battery. It was done.

In the present invention, the pyridine type polymer compound coated on at least the surface of the positive electrode structural member which is in contact with the non-aqueous electrolyte is, for example, poly-2-vinylpyridine hydrochloride or poly-4-vinylpyridine hydrochloride. Alternatively, a mixture of these may be used. Here, it is preferable that the average molecular weight of poly-2-vinylpyridine hydrochloride or poly-4-vinylpyridine hydrochloride is 21,000 or more as determined by the viscosity method.

In the present invention, the pyridine-based polymer compound film (adsorption layer) is formed on the surface of the required region of the positive electrode structural member by applying a pyridine-based polymer compound solution prepared by using an aqueous solution of HClO ₄ or the like as a solvent. , For example 50
It is carried out by heat treatment at a temperature of ~ 100 ° C.
This heat treatment temperature is appropriately selected depending on the composition and concentration of the pyridine polymer compound solution, but is generally 100
If the temperature exceeds ℃, the coating layer tends not to exhibit the required corrosion resistance, so it is preferable to set the temperature to 100 ℃ at most. In the present invention, examples of the positive electrode active material include active materials such as manganese dioxide, fluorocarbon, and thionyl chloride. The positive electrode active material is applied to a support surface made of stainless steel to form a positive electrode. . Further, examples of the negative electrode include metallic lithium foil and metallic sodium foil.

Examples of the non-aqueous electrolyte used in the present invention include ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfolane, acetonitrile, 1,2-dimethoxymethane, 1,3-dimethoxypropane, dimethyl ether, Lithium perchlorate (LiClO ₄ ), hexafluorophosphoric acid is added to an organic solvent (non-aqueous solvent) consisting of at least one selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl carbonate, diethyl carbonate and ethylmethyl carbonate. About 0.5 to 1.5 mol / l of lithium salt (electrolyte) such as lithium (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ). A dissolved non-aqueous electrolytic solution is generally mentioned. Instead of the non-aqueous electrolyte solution, an ion conductive solid electrolyte, for example, a polymer solid electrolyte obtained by compounding a lithium salt with a polymer compound may be used.

Further, as the separator for insulating and separating the negative electrode and the positive electrode, for example, a nonwoven fabric of polyolefin resin such as polyethylene or polypropylene or a porous film can be used.

According to the first aspect of the invention, in the non-aqueous electrolyte battery, at least the surface of the positive electrode constituent member in contact with the non-aqueous electrolyte is made of a pyridine-based polymer compound having excellent corrosion resistance to the non-aqueous electrolyte. It is covered with a film. That is, a pyridine-based polymer compound that acts as an inhibitor to the non-aqueous electrolyte solution and suppresses corrosion covers the surface of, for example, an outer can that also serves as a positive electrode terminal. Due to the action and effect of suppressing corrosion, the positive electrode constituent member contributes to maintaining and exhibiting a stable battery function, and functions as a highly reliable battery.

It is considered that the reason why the corrosion of the positive electrode constituent member is suppressed is as follows. First,
First, some of the N atoms of all pyridine rings in the pyridine-based polymer forming the coating film are not subjected to protonation,
This is because the lone electron pair of N atom causes chemical adsorption on the metal surface. Secondly, the N atom of the pyridine ring, which has undergone protonation to become N ⁺ , is physically adsorbed on the cathode site on the metal surface, and then the electron is supplied from the metal surface to reduce the N atom before it is isolated. This is because chemical adsorption occurs on the metal surface due to electron pairs.

In the invention of claim 2, the pyridine polymer compound is poly-2-vinylpyridine hydrochloride or poly-4-
The use of at least one vinylpyridine hydrochloride promotes stable battery functioning and high reliability of the positive electrode structural member.

In the third aspect of the invention, the pyridine polymer compound is at least one of poly-2-vinylpyridine hydrochloride and poly-4-vinylpyridine hydrochloride having a viscosity average molecular weight of 21,000 or more. Since the corrosion inhibiting performance of the structural member is further improved, the functional stability and high reliability of the battery can be easily achieved.

[0021] In the invention of claim 4, a positive electrode constituent member in which at least the surface in contact with the non-aqueous electrolytic solution is corrosion-inhibited with respect to the non-aqueous electrolytic solution can be provided easily and with good yield, so that it is stable. It will greatly contribute to the provision of highly reliable batteries that retain and exhibit battery functions.

According to the invention of claim 5, in the formation of the coating layer of the pyridine type polymer compound, the heat treatment temperature after application of the solution is set to 50 to 100 ° C. to suppress corrosion of the non-aqueous electrolyte. The positive electrode structural member thus prepared can be provided more easily and with higher yield.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

Example 1 FIG. 1 is a sectional view showing the structure of the main part of a non-aqueous electrolyte battery according to this example, and FIG. 2 is a partially enlarged sectional view of FIG. In FIGS. 1 and 2, reference numeral 1 denotes a stainless steel outer can that also serves as a positive electrode terminal in which a nonaqueous electrolytic solution (organic electrolytic solution) -based battery power generating element 2 is housed, and 3 denotes an outer case in which the battery power generating element 2 is housed. It is a stainless steel sealing body that also serves as a negative electrode terminal for airtightly sealing the opening of the can 1 by caulking and fixing it through an insulating packing material 4 made of synthetic resin. Here, the outer can 1 that also serves as a positive electrode terminal is referred to as a positive electrode constituent member together with a porous metal body (or current collector) 2a and a positive electrode mixture (positive electrode) 2b that form a part of a battery power generation element 2 described later.

In the above structure, the inner wall surface (side wall surface and bottom surface) of the outer can 1 which also serves as the positive electrode terminal is made of, for example, poly.
A thin film (adsorption film) 5 of 4-vinylpyridine hydrochloride is provided. That is, while rotating the outer can 1 horizontally, HClO in which 20 ppm of poly-4-vinylpyridine hydrochloride having a viscosity average molecular weight of about 22000 was dissolved in the peripheral portion of the bottom surface of the outer can 1.
12 μl of ₄ aqueous solution (HClO ₄ concentration 1N) was injected, and the poly-4-vinylpyridine hydrochloride solution was applied to the side wall surface and the bottom surface of the outer can 1 by the centrifugal force by the rotation, and the pressure was reduced by a vacuum dryer. On the other hand, heat treatment is carried out at 80 ° C. for about 5 hours to form a thin film 5 of poly-4-vinylpyridine hydrochloride.

Further, the battery power generating element 2 includes a conductive porous metal body (for example, a stainless steel-based metal sintered body) 2a impregnated with a non-aqueous electrolyte, manganese dioxide (a positive electrode active material), a conductive material and Positive electrode mixture (positive electrode) 2 made of a binder
b, a separator 2c made of a microporous polypropylene resin film having a thickness of 0.025 mm, a negative electrode 2d made of, for example, a metallic lithium foil, and a non-aqueous electrolyte 2e.

The non-aqueous electrolyte battery having the above structure was stored at a temperature of 60 ° C. for 100 days and the number of corrosion occurrences was examined. All 100 non-aqueous electrolyte batteries used in the test showed corrosion occurrence. Was not recognized.

On the other hand, for comparison, in the non-aqueous electrolyte battery having the above-described structure, the same condition is used except that the coating of the poly-4-vinylpyridine hydrochloride thin film 5 on the inner wall surface of the outer can 1 is omitted. When the same test was performed on 100 non-aqueous electrolyte batteries thus prepared, corrosion was found on 14 of them.

Example 2 In this example, in the case of Example 1 described above, the side wall and the bottom of the outer can 1 were coated with a solution of poly-4-vinylpyridine hydrochloride by centrifugal force due to rotation, and then vacuum dried. It shows the effect of the heat treatment when the heat treatment is carried out while reducing the pressure in the machine to form the coating of the poly-4-vinylpyridine hydrochloride thin film 5.

That is, the heat treatment temperature is 45 ° C., 50 ° C., 80
℃, 100 ℃ or 105 ℃, and set the required poly-4-vinylpyridine hydrochloride thin film 5 on the inner wall of the outer can 1, respectively.
Table 1 shows the results of the same test using the attached outer can 1 for each 100 non-aqueous electrolyte batteries similar to those shown in FIG.

Table 1 Heat treatment temperature (° C) Number of corrosion occurrences Non-aqueous electrolyte battery 2a 45 7 Non-aqueous electrolyte battery 2b 50 0 Non-aqueous electrolyte battery 2c 80 0 Non-aqueous electrolyte battery 2d 100 0 Non-aqueous electrolyte Battery 2e 105 6 As can be seen from Table 1, the heat treatment temperature is 45 ° C or 1
When the temperature was set to 05 ° C, sufficient corrosion inhibition or prevention effect could not be added to the outer can 1, but the heat treatment temperature was 50%.
It was confirmed that when the temperature was set to ℃ or 100 ℃, stable battery function was exhibited without the occurrence of corrosion.

Example 3 In this example, in the case of Example 1, the poly-4-vinylpyridine hydrochloride solution was applied to the side wall surface and the bottom surface of the outer can 1 by centrifugal force due to rotation and then vacuum dried. Concentration of the poly-4-vinylpyridine hydrochloride solution, coating amount, and heat treatment conditions (temperature and time) when the thin film 5 of poly-4-vinylpyridine hydrochloride is coated by heat treatment under reduced pressure with a machine. ) Shows the effect of.

That is, the solution concentration is set to 5 ppm to 20 ppm, the coating amount is 5 to 20 μl, the heat treatment temperature is set to 50 to 100 ° C., and the heat treatment time is set to 1 to 20 hours. Using the outer can 1 with the poly-4-vinylpyridine hydrochloride thin film 5 coated with the poly-4-vinylpyridine hydrochloride thin film 5 described above, 100 non-aqueous electrolyte batteries similar to those shown in FIG. Table 2 shows the results of the same test.

Table 2 Solution concentration Coating amount Heat treatment time Corrosion generation (ppm) (μl) Temperature (° C), time (h) Number Non-aqueous electrolyte battery 3a 5 10 100 1 0 Non-aqueous electrolyte battery 3b 20 5 50 20 0 Non-aqueous electrolyte battery 3c 10 15 90 5 0 Non-aqueous electrolyte battery 3d 5 25 70 10 0 Non-aqueous electrolyte battery 3e 5 20 90 5 0 As can be seen from Table 2, poly-4-vinylpyridine hydrochloride It was confirmed that even if the concentration of the solution, the coating amount, the heating time, etc. were changed, the occurrence of corrosion was not observed and a stable battery function was exhibited.

In the above, the non-aqueous electrolyte primary battery using poly-4-vinylpyridine hydrochloride as the pyridine-based polymer compound has been exemplified, but poly-2-vinylpyridine hydrochloride is used instead of poly-2-vinylpyridine hydrochloride. With vinyl pyridine hydrochloride, or with poly-4-vinyl pyridine hydrochloride
Similar effects can be obtained by using a mixed system with 2-vinylpyridine hydrochloride. In addition, similar effects can be obtained in the non-aqueous electrolyte secondary battery.

[0036]

As described above, according to the non-aqueous electrolyte battery of the present invention, at least the surface of the positive electrode constituent member, which is easily eluted by the non-aqueous electrolyte solution, in contact with the non-aqueous electrolyte solution has a high pyridine content. The coating with the molecular compound layer imparts excellent corrosion resistance to the non-aqueous electrolyte. The positive electrode components such as stainless steel are not corroded or damaged by the non-aqueous electrolyte, so that the phenomenon of resistance increase inside the battery due to metal deposition on the negative electrode surface is also avoided and stable discharge characteristics over a long period of time. Is ensured, it functions as a highly reliable non-aqueous electrolyte battery.

Further, according to the method for producing a positive electrode constituent member for a non-aqueous electrolyte battery according to the present invention, a stable positive electrode constituent member for a non-aqueous electrolyte solution can be easily provided with a good yield. It greatly contributes to the practical application of a non-aqueous electrolyte battery having high properties.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a configuration example of a main part of a non-aqueous electrolyte battery according to an embodiment.

FIG. 2 is a partially enlarged vertical sectional view of the non-aqueous electrolyte battery shown in FIG.

[Explanation of symbols]

 1 ... Outer can 2 ... Battery power generating element 2a ... Porous body (current collector) 2b ... Positive electrode 2c ... Separator 2d ... Negative electrode 2e ... Non-aqueous electrolyte 3 ... Sealing body 4 ... Insulation Packing material 5 ... Adsorption film (pyridine-based polymer compound layer)

Claims (5)

[Claims] 1. A non-aqueous electrolyte battery comprising a negative electrode constituent member, a positive electrode constituent member, and a non-aqueous electrolyte solution as a battery power generating element, wherein at least one of the positive electrode constituent members is in contact with the non-aqueous electrolyte solution. Is covered with a film of a pyridine polymer compound. 2. The non-aqueous electrolyte battery according to claim 1, wherein the pyridine polymer compound is at least one of poly-2-vinylpyridine hydrochloride and poly-4-vinylpyridine hydrochloride. . 3. The pyridine polymer compound is at least one of poly-2-vinylpyridine hydrochloride and poly-4-vinylpyridine hydrochloride having a viscosity average molecular weight of 21,000 or more. The non-aqueous electrolyte battery according to claim 2. 4. A method for producing a positive electrode constituent member for a non-aqueous electrolyte battery, wherein a pyridine-based polymer compound solution is applied to at least a surface of the positive electrode constituent member that is in contact with the non-aqueous electrolyte solution, and heat treatment is performed to obtain pyridine. A method for manufacturing a positive electrode constituent member for a non-aqueous electrolyte battery, which comprises forming an adsorption layer made of a polymer compound. 5. The method for producing a positive electrode constituent member for a non-aqueous electrolyte battery according to claim 4, wherein the heat treatment temperature is 50 to 100 ° C.