JPH04206149A - Inorganic nonaqueous electrolyte battery and manufacture thereof - Google Patents

Abstract

PURPOSE:To heighten utilization factor for an active material of thionyl chloride in high rate discharge and obtain a battery having a large capacity by arranging cracks at least on the surface of a porous body of a positive electrode. CONSTITUTION:In a battery which uses oxyhalide as solvent for electrolyte and positive electrode active material and uses lithium as negative electrode active material, cracks 12 having a prescribed range of width and length are provided on the surface of a porous body 3 of a positive electrode. The porous body 3 is formed by mixing a prescribed volume of acetylene black and graphite together, and dispersion solution of polytetrafluoroethylene, ethyl alcohol and water are added so as to be kneaded together. Next, the kneaded material is pushed out by means of a screw so as to be formed in a columnar shape by means of a molding machine. The porous body 3 obtained by this manufacturing method has the cracks 12 on the surface, and the cracks extend inside of the porous body. Thereby, solution of thionyl chloride can infiltrate easily into the porous body 3 in high rate discharge so that the discharge capacity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inorganic non-aqueous electrolyte battery using an oxyhalide as a solvent of an electrolyte and a positive electrode active material, and lithium as a negative electrode active material.

Conventional technology Inorganic non-aqueous electrolyte batteries that use oxyhalides such as thionyl chloride as the electrolyte solvent and positive electrode active material and lithium as the negative electrode active material have a lower energy density than other non-aqueous electrolyte batteries. Recently, it has been attracting attention due to its high temperature and excellent low-temperature properties.

A conventional inorganic non-aqueous electrolyte battery will be described below.

FIG. 4 is a sectional view of a conventional inorganic non-aqueous electrolyte battery. In FIG. 4, 1 is a negative electrode made of lithium, 2 is a separator made of glass fiber nonwoven fabric, and 3 is a positive electrode porous body made of carbon. 4 is a positive electrode current collector rod made of nickel;
5 is a battery container made of stainless steel that also serves as a negative electrode current collector. 6 is a sealing plate made of stainless steel, and this sealing plate 6
The outer periphery of the battery container 5 is welded to the opening of the battery container 5. A glass seal 7 is formed on the inner peripheral side of the sealing plate 6, and after injecting electrolyte from a metal tube 9 that has been welded to the glass seal 7 in advance, the upper end of the positive electrode current collector rod 4 and the metal tube 9 are welded. The inside of the battery is sealed. The electrolyte for this battery is, for example, thionyl chloride:LiAec (!
4 dissolved in a ratio of 1.5 mol/1 is used, and the above-mentioned thionyl chloride acts as a positive electrode active material.

10 is a separator paper made of the same material as the separator. 8 is a void, and 11 is a free thionyl chloride electrolyte present in the void 8.

FIG. 3 is a perspective view of a conventional positive electrode porous body. The material consists of acetylene black, graphite, and a fluororesin as a binder, and the weight ratio thereof is 90:10:10.

The shape is cylindrical, and the porosity is 80%.

The manufacturing method involves extruding a mixture of acetylene black, graphite, binder, methanol, and water into a column shape using a hydraulic extrusion molding machine or a screw extrusion molding machine. The amount of binder at this time was 120 i or less of the total amount of the positive electrode porous material.

Problems to be Solved by the Invention However, in the above configuration, during high rate discharge, the free thionyl chloride liquid outside the positive electrode porous body, which serves as the positive electrode active material, does not enter the positive electrode porous body, and the discharge capacity is reduced. The problem was that there were few.

The present invention solves the above-mentioned conventional problems, and aims to provide a large-capacity inorganic non-aqueous electrolyte battery that increases the utilization rate of thionyl chloride active material in high-rate discharge.

Means for Solving the Problems To achieve this object, the inorganic non-aqueous electrolyte battery of the present invention is provided with a crack on at least the surface of the positive electrode porous body, preferably a crack extending from the surface of the positive electrode porous body to the inside thereof. It has a configuration with.

Effect: With this configuration, the thionyl chloride solution, which is the positive electrode active material, sufficiently penetrates into the inside of the positive electrode porous body, and as a result, it is possible to realize an improvement in the discharge capacity during high rate discharge.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

Since the battery structure of the present invention is the same as the conventional one, it will be explained with reference to FIG. FIG. 4 is a sectional view of an inorganic non-aqueous electrolyte battery. In FIG. 4, 1 is a negative electrode made of lithium with a thickness of 0.9 nua, 2 is a separator made of a nonwoven glass fiber fabric with a thickness of 0.2 nm, 4 is a positive electrode current collector rod made of nickel, and 5 is a negative electrode made of lithium with a thickness of 0.9 nua.
Reference numeral denotes a battery container made of stainless steel and serving as a negative electrode current collector with a thickness of 0.3+mn; 6, a sealing plate 1 made of stainless steel; and the outer periphery of the sealing plate 6 is welded to the opening of the battery container 5. In this welding method, metals are thermally melted and bonded by irradiating laser light. A glass seal 7 is formed on the inner peripheral side of the sealing plate 6, and after injecting an electrolyte through a metal tube 9 that has been welded to the glass seal 7 in advance, the upper ends of the positive electrode current collector rod 4 and the metal tube 9 are exposed to a laser beam. The interior of the battery is closed by welding by irradiation. Reference numeral 10 indicates a separator paper made of the same material as the separator, 8 indicates a void, and 11 indicates a free thionyl chloride electrolyte, which is present between the void 8 and the separator 2 and the positive electrode porous body 3 of the present invention. exists in

Furthermore, the thionyl chloride electrolyte is also contained in the separator 2 and the positive electrode porous body 3.

FIG. 1 shows a perspective view of a positive electrode porous body according to an example of the present invention.

A crack 12 with a width of 0.05 to 0.3wn and a length of 1 to 5M is provided on the surface of the positive electrode porous body 3. This positive electrode porous body 3 is a mixture of acetylene black, graphite, and a fluororesin binder. In addition, the porosity is 82% so that the thionyl chloride solution can be impregnated.

Figure 2 shows a cross-sectional view of the positive porous body shown in Figure 1 taken along the X-X'' axis.There are cracks 12 on the surface of the positive porous body 3, and these cracks are as shown by 13. It extends to the inside of the positive electrode porous body 3.

The method for manufacturing the positive electrode porous body of the present invention will be explained below. 90 parts by weight of acetylene black with a particle size of about 50 μm and 10 parts by weight of graphite with a particle size of 20 μm are mixed. A polytetrafluoroethylene dispersion solution (solid content 50%) was added to 100 parts by weight of the mixture thoroughly mixed in a dry method.
0 parts by weight and 50 parts by weight of ethyl alcohol and 100 parts by weight of seven bottles were added and kneaded. This kneaded material is molded into a columnar shape using a screw extrusion molding machine. The screw diameter of the screw extrusion molding machine was 15 cm, and the rotation speed was 10 rpm. Now extrude it into a column shape with a diameter of 10 mm and a length of 301 W.
Cut into l. The positive electrode porous body obtained by this manufacturing method has cracks on the surface, and the cracks further extend into the inside of the positive electrode porous body. The binder content of the obtained positive electrode porous body was 17% of the total amount, and the porosity was 82%.

In order to create a crack in a columnar positive electrode porous body, it must be formed into a columnar shape using a screw extruder, and the binder content in the positive electrode porous body must be increased from 15'o to 30% of the total amount. If it is less than δ, cracks may occur or it cannot be obtained by molding with a screw extrusion 7 molding machine. 30 on the other hand? At δ or more, it becomes difficult for the thionyl chloride solution to penetrate into the positive electrode porous body, and the discharge capacity decreases. The reason why cracks form is that the kneaded material is cut by the screw blades and the cut surface remains as a crack.The reason cracks form at 15% is that the bonding strength of the kneaded material is strong (because the cut surface by the screw This is because the difference between the bond strength and the bond strength is large.

The discharge characteristics of the battery of this example configured as described above will be explained below. Figure 5 shows two types of batteries: the present invention and the conventional battery.
A comparison of 120 ohm continuous characteristics at 0°C is shown. A is a battery according to an embodiment of the present invention, and B is a conventional battery. A positive electrode porous body having a diameter of 10 mm and a length of 30 wn was prepared in the same manner. The same amount of electrolyte solution, 4.0 (5), was injected. Battery dimensions are AA size, height is 50.5mm, diameter is 14.5mm
It is mm.

It was prepared in the same manner with the amount of lithium being 580 mg.

As shown in FIG. 5, the battery A of the present invention has a discharge capacity that is approximately 30% larger than the conventional battery B. As described above, according to this example, by providing cracks on the surface of the positive electrode porous body, the thionyl chloride solution easily penetrates into the positive electrode porous body during high rate discharge, and the discharge capacity can be improved.

In this example, thionyl chloride was used as the electrolytic solution and the positive electrode active material, but sulfolyl chloride, sulfuryl chloride, etc. may be used instead.

Effects of the Invention As described above, the present invention uses an oxyhalide as a solvent of an electrolytic solution and a positive electrode active material, uses lithium as a negative electrode active material,
In an inorganic non-aqueous electrolyte battery comprising a positive porous body facing the negative electrode with a separator in between, it is preferable that cracks are provided on the surface of the positive porous body so that the cracks are removed from the surface of the porous body. By extending to the inside, the oxyhalide solution can easily penetrate into the positive electrode porous body, and the effect of increasing the discharge capacity especially in high rate discharge can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a porous positive electrode used in the battery of the present invention, FIG. 2 is a cross-sectional view taken along line xx' in FIG. 1, and FIG. 3 is a perspective view of a conventional porous positive electrode. FIG. 4 is a sectional view of a typical inorganic non-aqueous electrolyte battery, and FIG. 5 is a comparison diagram of the discharge performance of a conventional inorganic non-aqueous electrolyte battery according to the present invention. 1... Negative electrode, 2... Separator, 3...
・Porous positive electrode, 5...Battery container, 6...
... Sealing plate, 11... Thionyl chloride solution,
12...Crack, 13...Crack extending inside the positive electrode porous body.

Claims (3)

[Claims] (1) In an inorganic non-aqueous electrolyte battery comprising an oxyhalide as an electrolyte solvent and a positive electrode active material, lithium as a negative electrode active material, and a positive electrode porous body facing the negative electrode with a separator interposed therebetween, the An inorganic non-aqueous electrolyte battery in which a crack is provided at least on the surface of a positive electrode porous body. (2) The inorganic non-aqueous electrolyte battery according to claim 1, wherein a crack is provided extending from the surface of the positive electrode porous body to the inside thereof. (3) In an inorganic non-aqueous electrolyte battery comprising an oxyhalide as an electrolytic solution solvent and a positive electrode active material, lithium as a negative electrode active material, and a positive electrode porous body facing the negative electrode with a separator interposed therebetween, the The positive electrode porous body is molded by screw extrusion, and the molded positive electrode porous body contains an inorganic non-aqueous material in which the fluororesin binder content of the molded positive electrode porous body is from 15% to 30% of the total amount, and at least cracks are provided on the surface. Method of manufacturing electrolyte batteries.