JPS59217946A - Manufacture of nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To obtain a nonaqueous electrolyte battery having an increased discharge capacity by subjecting a molded positive mixture containing carbon fluoride as an active material to heat treatment at high temperature and in the atmosphere. CONSTITUTION:In assembling a battery in which an alkali metal such as metallic fluoride is used as a positive active material and nonaqueous electrolyte is used, a molded positive mixture 4 is subjected to heat treatment carried out at 200-380 deg.C in the atmosphere. After the positive mixture pellet 4 is installed in a plate-like separator 3, the separator 3 is brought into contact with the negative lithium electrode 2 before the battery is sealed, thereby constituting a coin- type battery. By thus subjecting the positive mixture 4 to heat treatment in the atmosphere, low discharge voltage which is disadvantage of the conventional battery is eliminated and an increased discharge capacity is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a non-aqueous electrolyte battery.

Structure of conventional examples and their problems Typical non-aqueous electrolyte batteries that use alkaline gold as the cathode active material are fluorinated carbon V that uses fluorinated carbon as the anode active material and lithium as the cathode active material. There is a lithium battery.

The conventional structure of this type of coin-type battery was to place an anode mixture formed into a disc shape with a separator in between a cathode sealing lid to which lithium was crimped, and a non-aqueous non-aqueous battery consisting of an organic solvent and an inorganic electrolyte. A predetermined amount of electrolyte was injected, and a case that also served as an anode terminal was placed over and sealed.

Batteries that use alkali metals such as lithium as the cathode active material have strong reactivity with water, so
An organic solvent from which water has been removed is used as the electrolyte, and each of the other layers constituting the battery is sufficiently dried, and the battery assembly is also carried out in air or an inert gas atmosphere from which water has been removed.

Lithium batteries that use carbon heptadide as the anode active material differ from manganese dioxide used in manganese/lithium batteries, which are the other typical lithium battery, because carbon fluoride itself is water repellent. Drying the anode mixture takes 15 minutes.
Drying was carried out at a temperature of 0° C. or lower, usually about 6° C. to 100° C. Under these conditions, it was possible to dry the battery to a level of moisture that did not cause problems in terms of battery characteristics. Batteries constructed in this manner have excellent storage stability and a flat discharge voltage, so they have been widely used in electronic devices such as electronic watches. However, the operating voltage is 2.7~2.
9. Since it is about 0.2V lower than the 2.9 to 3.1V of a manganolithium battery using manganese dioxide as anode active material, the range of usage limits for ICs, LSIs, etc. is narrow, and the field of use of batteries is ICs that are limited or selected to match this voltage.

Since LSI must be used, there is a problem in that it causes an increase in the cost of the equipment.

Purpose of the Invention The present invention has been developed by heat-treating an anode mixture containing fluorocarbon as an active material in the atmosphere at a higher temperature than ever before. The purpose is to eliminate the drawback of low battery operating voltage and to increase discharge capacity.

Structure of the Invention The present invention is characterized in that an anode mixture consisting of fluorocarbon as an active material, a conductive material, and a binder is molded according to the battery size, and then heat-treated in the atmosphere at a temperature of 200 to 380°C. It's an old thing. With this heat treatment,
By adsorbing oxygen to the anode mixture and making the adsorbed oxygen contribute to the discharge reaction, it is possible to increase the discharge voltage and increase the discharge capacity.

Description of examples Hereinafter, the present invention will be explained in detail with reference to Examples.

As shown in Fig. 1, a dish-shaped separator 3 is placed on a sealing lid 1 that has been pressurized with metallic lithium 2, and after pouring an electrolyte consisting of globylene carbonate, dimethoxy/ethane, and lithium borofluoride, an anode mixture is prepared. pellet 4 to lithium 2
to face. The mixture was made by mixing 100 parts of carbon heptanoide, 10 parts of acetylene black, and 5 parts of fluororesin binder in a weight ratio, forming a disc-shaped pellet VC with a diameter of 14.0 vm and a thickness of 0.6 trrrn, and then heating it at 260°C. The mixture was heated in an electric furnace at a temperature of 3 hours and then cooled. This mixture pellet 4 is housed in a dish-shaped separator 3 and is paired with lithium 2. Thereafter, the case 5 was placed on the sealing lid 1, and the end of the case was curled inward and sealed by tightening the gasket 6 to form a coin-shaped battery having a diameter of 20 mm and a thickness of 1.6 mm. For heat treatment of the mixture, 80℃, 1
40℃, 200℃, 260'C, 320℃, 380℃,
Experiments were conducted at each heating temperature of 440°C. Moreover, the heat treatment time was 3 hours in all cases.

FIG. 2 shows the discharge curves at 20° C. with a load resistance of 3 kΩ for a battery a using a mixture heated at 260° C. of the present invention and a battery A using a conventional mixture dried at 80° C. As is clear from FIG. 2, in the battery of the present invention, the battery voltage during discharging is kept high and the discharge duration is also extended.

The discharge voltage (at 50% discharge) and discharge duration at 20°C with a 30Ω load at each heat treatment temperature are shown in Figures 3 and 4.
As shown in the figure, a battery using an anode mixture heat-treated at 200 to 380°C has a high discharge voltage and a long discharge duration. This is thought to be because oxygen in the air is adsorbed by the anode mixture by heating the anode mixture to a high temperature in the air, and this adsorbed oxygen acts as an anode active material.

Although the mechanism of the discharge reaction is not clear,
Generally speaking, the battery reaction between carbon fluoride and lithium is (CF)n+ nLi −+ nC+ nLiF, and the actual operating voltage in the battery is 2.7 to 2.9V,
The discharge capacity is obtained at a utilization rate of approximately 90% of the theoretical capacity of fluorocarbon of 864 mAh/q. In a battery using an anode mixture subjected to high-temperature heat treatment, in addition to the above reaction, the reaction between adsorbed oxygen and lithium 02+ 4Li-+ 2Li20 (
E'2.9'V) occurs. That is, adsorbed oxygen acts as an anode active material, resulting in an operating voltage of 2.8~
3. It is thought that the discharge capacity was higher than the filling amount of fluorocarbon.

In the heat treatment at a temperature of 200° C. or lower, the adsorption reaction between the anode mixture and oxygen does not take place sufficiently, and only a discharge reaction of fluorocarbon occurs. When the temperature reaches over 380℃,
The fluorocarbon and the binder in the mixture begin to decompose,
On the contrary, this resulted in a decrease in discharge voltage and discharge capacity.

From this, in order to make the anode mixture adsorb oxygen and stably increase the discharge voltage and capacity, it is necessary to
It can be said that heat treatment of the anode mixture at a temperature of °C is suitable. Regarding the heating time, a heating time of 10 minutes or more is effective, but 1 to 6 hours is appropriate in view of the reliability of oxygen adsorption and the decomposition of fluorocarbon and binder due to long heating.

Effects of the Invention As described above, the present invention provides an anode mixture for a non-aqueous electrolyte battery containing fluorocarbon as an active material at a temperature of 200 to 380% in the atmosphere.
By heat-treating at a temperature of .degree. C., one of the drawbacks of conventional batteries, that is, the discharge voltage is low, can be solved, and the discharge capacity can be increased.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a flat non-aqueous electrolyte battery obtained according to an example of the present invention, Figure 2 is a diagram showing the discharge curves of the battery of the present invention and a conventional battery, and Figure 3 is a diagram showing the anode mixture. Figure 4 shows the relationship between the heat treatment temperature of the anode mixture and the discharge sustaining voltage when each battery is discharged at 60%. Figure 4 shows the heat treatment temperature of the anode mixture and the discharge duration when each battery is discharged. FIG. 1...lunar palate, 2...cathode lithium, 3
... Separator, 4 ... Anode mixture, 5
・・・・・・Case, 6-・・・Gasket. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4.5 Figure 2 o zoo 4oo 6θo ao. Continuous U valve interval (h) 43Fig. 10θ 200 300 40゜1 mark (°0)

Claims (1)

[Claims] Fluorinated carbon is used as the anode active material, alkali metal is used as the cathode active material,
A method for manufacturing batteries using non-aqueous electrolytes as the electrolyte, in which a molded anode mixture is exposed to an odor of 200 to 38
A method for manufacturing a non-aqueous electrolyte battery characterized by heat treatment at a temperature of 0°C.