JPS60216463A - Cell - Google Patents

Abstract

PURPOSE:To decrease the aging change of a cell, extend its life, and improve the reliability by using a specific copolymer made of dimethyl siloxane and polyethylene oxide and metal ions of I or II group as the main constituent of an ion conductive material. CONSTITUTION:An ion conductive compound containing a bridge-solidified copolymer made of dimethyl siloxane and polyethylene oxide as expressed by a constitutional formula and an electrolyte made of metal ions of I or II group is used as the main constituent of the ion conductive material of a cell. Accordingly, the solid cell having no danger of leakage and high reliability can be formed. Furthermore, the cell has little aging deterioration and can be stored and used at a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to radio waves, and particularly to a battery containing an ionically conductive compound whose main component is a polymer compound.

(Prior Art) In recent years, with the rapid spread of small or portable electronic devices, the demand for small, high-performance batteries as their power sources is rapidly increasing. These batteries are required not only to have high performance such as high energy density and high rate discharge, but also to have a long life and high reliability.

Batteries are generally classified into wet type batteries and solid-state batteries depending on the materials used, but at present, batteries called wet type batteries have good characteristics and are low in price, so they are widely put into practical use. .

However, since wet-type batteries use an electrolyte solution as an ion-conductive material, that is, a material containing a liquid such as water or an organic solvent, there is always the problem of liquid leaking to the outside of the battery. This may cause deterioration of battery performance and damage to peripheral components. Although great efforts have been made to improve the leakage of wet batteries, the risk of leakage still cannot be completely eliminated and the batteries have the disadvantage of being insufficient in terms of high reliability.

On the other hand, solid-state batteries inherently have the potential to be highly reliable and long-lasting batteries, but they have not been widely put into practical use mainly due to the characteristics of the solid electrolyte that is the ionic conductive material, and drawbacks such as price and processability. This has not yet been achieved.

In order to improve the above-mentioned drawbacks of conventional batteries, the inventors have developed solid ion-conductive materials containing a series of polymer compounds as main components. In other words, the patent application 1986-0
22570.56-022571.

The ionically conductive circular body compositions disclosed in Patent No. 56-029090 and No. 56-029091 are examples of such compositions.

The ionic conductive circular body composition is an organic polymer compound.

It mainly consists of three components: an organic solvent and an electrolyte, and has relatively high ionic conductivity and good mechanical workability. Batteries using this ion conductive material are superior to wet batteries in terms of reliability and superior to solid batteries in terms of practicality.

However, since conventional ionically conductive circular body compositions contain organic solvents, the organic solvents tend to vaporize in small amounts in storage environments, particularly in high-temperature environments, and as a result, ionic conductivity may deteriorate over time. be. Even if the degree of deterioration over time is very small, it will affect the product's lifespan.

This is a major drawback in batteries that require high reliability.

(Object of the Invention) An object of the present invention is to provide a battery that eliminates such conventional drawbacks.

(Structure of the Invention) According to the present invention, dimethylsiloxane and poly(ethylene oxide) are used as ionically conductive materials for batteries.
A battery is obtained which is characterized in that it uses as a main component an ionically conductive compound containing a copolymer with a metal ion of Group 1 or Group 2 of the periodic table, and an electrolyte comprising a metal ion of Group 1 or Group 2 of the periodic table.

Copolymers of dimethylsiloxane and poly(ethylene oxide) are generally copolymers of dimethyldichlorosilane and poly(ethylene oxide).
(ethylene glycol), and is obtained as an alternating comonomer by dehydrochloric acid polycondensation reaction. Copolymers using poly(ethylene glycol) with relatively small repeating units, such as di(ethylene glycol), tri(ethylene glycol), or tetra(ethylene glycol), are liquid. Since this copolymer has an ethylene oxide group in its main chain, it can easily dissolve and dissociate electrolytes such as lithium perchlorate and sodium thiocyanate. Furthermore, the dimethylsiloxane group functions to lower the glass transition point of the copolymer and increase the mobility of ions.

By crosslinking and solidifying a copolymer having such properties and further dispersing an electrolyte, a solid ionically conductive compound can be obtained. Therefore, when forming a lithium battery etc., by using a solid positive electrode active material,
A complete solid state battery is obtained. Further, this ion conductive compound is a material that can realize the excellent mechanical properties of a polymer compound, and can be easily processed into various battery shapes such as a stacked type, a rolled type, or a sheet type.

(Example) 5- Hereinafter, the present invention will be explained in detail by way of an example with reference to FIGS. 1 and 2.

A case will be described in which a coin-type battery as shown in FIG. 1 is manufactured using lithium as a negative electrode active material and manganese dioxide as a positive electrode active material.

The ion conductive diaphragm 1 was prepared as follows.

65.1 gr of dimethyldichlorosilane and 55.6 gr of tetra(ethylene glycol) were reacted in benzene with stirring for 72 hours while maintaining the temperature at 0°C, and the reaction was further heated to 60°C to promote the reaction for 72 hours. After that, the reaction was completed at a temperature of 60°C under reduced pressure for 48 hours to complete the reaction.
A copolymer was obtained. Progress and completion of the desired reaction was confirmed by nuclear magnetic resonance spectroscopy (NMR).

Next, the obtained copolymer 1. Mix Ogr, 0.15 gr of triethylene glycol dimethacrylate, and 0.12 gr of hendiyl peroxide, and after casting this on a Teflon plate, heat it at a temperature of 120°C for 24 hours to solidify the "C" crosslinking. A white film 6- with a thickness of 60 μm was obtained.

After immersing this membrane in acetone to wash away decomposition products, uncrosslinked substances, unreacted monomers, etc., a solution of 31 parts by weight of lithium perchlorate dissolved in acetone per 20 parts by weight of the membrane was added to the membrane. After swelling, the acetone was dried and removed to solidify to obtain a thin film of the ionically conductive compound. Through this operation, lithium perchlorate, which is an electrolyte, was introduced into the membrane. The introduced lithium perchlorate was quantified by halogen analysis and found to have a composition ratio of 131i%. This thin film was punched out to a diameter of 20 mm to obtain an ion conductive diaphragm 1.

A thin film of the above-mentioned ion conductive compound was punched out to a diameter of 10 m, sandwiched between lithium foils, and the ionic conductivity was measured using alternating current at a frequency of 1 K Hz, and the result was 3.2×10 8
The values of /c and m were obtained. Fortunately, this thin film had good strength and flexibility, and could be easily processed into various shapes.

Positive electrode body 2 was prepared as follows.

As the ion conductive material, an ion conductive composition composed of polyvinylidene fluoride, lithium perchlorate and propylene carbonate was used, and manganese dioxide and carbon as a conductive agent were mixed in a weight ratio of 4:15.
: 1, and then 0.7g of this mixture was heated to
Pressure molding was performed at ookg/cd. This results in a diameter of 18
A positive electrode body 2 having a thickness of about 1.0 mm and a thickness of about 1.0 mm was obtained.

The negative electrode body 3 was prepared by punching out a lithium sheet with a thickness of 0.4 rrvn into a diameter of 17wn.

Next, positive electrode body 2. Ion conductive diaphragm 1. The negative electrode body 3 is stacked and housed in upper and lower outer cases 4 and 5 as shown in FIG.
The end of the outer case 5 was caulked and sealed via the insulating ring 6 to produce a coin-type battery with an outer diameter of 22mm and a thickness of 23cm. A load resistor of 100Ω to 100Ω was connected to this battery, and the discharge characteristics were measured, and the results are shown in A of FIG. Furthermore, after storing this battery in a constant temperature bath at a temperature of 60°C for 20 days,
The discharge characteristics were measured in the same manner. The results are shown in FIG. 2B. Despite being stored at high temperatures, good properties were obtained with almost no property deterioration. Furthermore, this battery did not leak or burst at all during storage and characteristic measurements.

In addition, (a) In this example, battery production 1!8! All steps up to this point were performed in an argon inert gas atmosphere.

(b) In this example, a polymer compound obtained by crosslinking and solidifying a copolymer of dimethylsiloxane and tetra(ethylene oxide) was used as the material for the ion-conductive diaphragm 1. Even if we change the number of ethylene oxide groups, i.e. di(ethylene oxide), tri(
A similar effect was obtained with ethylene oxide).

(c) In this example, lithium perchlorate was used as the electrolyte for the ion conductive diaphragm 1, but the ethylene oxide group in the ion conductive compound has the effect of increasing solubility in various electrolytes. Similar effects were obtained using electrolytes such as lithium thiocyanate, lithium borofluoride, and sodium thiocyanate.

As described above, the present invention has the following effects.

(1) Highly reliable solid-state batteries can be created without the risk of leakage.

9- (II) It has little deterioration over time and can be stored and used at high temperatures.

(iii) The ion conductive diaphragm has good mechanical workability, and batteries of various shapes can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a coin-type battery according to the present invention, and FIG. 2 shows its discharge characteristics. 1... Ion conductive diaphragm, 2... Positive electrode body, 3... Negative electrode body, 4, 5... Exterior case, 6... °Insulation ring, A...discharge characteristics, B...discharge characteristics after storage at a temperature of 60°C for 20 days. 10-

Claims (1)

[Claims] As an ion-conductive material for batteries, the main component is an ion-conductive compound containing a copolymer of cross-linked solidified tilsiloxane and poly(ethylene oxide), and an electrolyte consisting of metal ions from Group I or Group II of the periodic table. A battery characterized by being used as a battery.