JPS61237369A - Organic electrolyte cell - Google Patents

Abstract

PURPOSE:To suppress increase of shortcircuit current and inner resistance by adding active carbon into a cell thereby adsorbing or decomposing the impurities contained in organic electrolyte. CONSTITUTION:The positive electrode black mix 5 is molded into a pellet by adding 10wt% of acetylene black and active carbon into 100wt% of active substance or carbon fluoride then mixing 5wt% of rubber binder. The electrolyte is composed of gamma-butyrolactone and 1,2-dimethoxy ethane dissolved with 1mol/l of lithium fluoroboride. These cell members are mounted in the case 1 and the sealing board 2 then the end section of case is caulked through a polypropylene packing 7 thus to produce a flat cell. When compared with conventional cell A, the shortcircuit current level will increase by 20-30% while the inner impedance after storage is low and the storage characteristic is stable. The adding quantity of active carbon is in the range of 0.01-0.035mg/mAh per capacity.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in organic electrolyte batteries.

Conventional technology Organic electrolyte batteries have high energy and are long-lasting.

Due to its excellent leakage resistance, it has come to be used as a power source for various electronic devices, including small electronic devices such as watches and calculators, as well as cameras and computers.

Problems to be Solved by the Invention As described above, organic electrolyte batteries are high-energy and highly reliable batteries, but on the other hand, because they use an inorganic electrolyte dissolved in an organic solvent as the electrolyte, they are not compatible with aqueous solutions. Compared to batteries that use electrolyte, there was a problem that the electrolyte contained less conductive dust, making it difficult to extract a large current. In particular, a 7-notium fluoride battery that uses carbon fluoride as a positive electrode active material and lithium as a negative electrode active material has a problem in that the voltage drops significantly at the beginning of discharge, which is a problem in applications where large currents flow.

One reason for this is that the conductivity of the organic electrolyte itself is low, but impurities such as peroxide contained in the organic electrolyte may form a passivation film of organic matter on the surface of the negative electrode active material. It is possible to form a

This passivation film became a resistor, making it difficult to extract large currents. In addition, when storing batteries for a long period of time, the formation of a film progresses, especially due to high temperature storage, resulting in a large increase in internal impedance.

The present invention solves the characteristic disadvantage of conventional organic electrolyte batteries in that it is difficult to extract such a large current, and also eliminates the initial voltage drop phenomenon seen in fluorocarbon/lithium batteries. The purpose of this is to suppress the increase in internal impedance.

Means for Solving the Problems In the present invention, in order to solve these problems, activated carbon is added to the battery, and preferably the positive electrode active material 1
mAh This o, o○3~0.06■ is added.

Effect: According to this configuration, the activated carbon adsorbs or decomposes impurities such as peroxide contained in the organic electrolyte, and the active state of the surface of the negative electrode active material is maintained, resulting in an increase in short circuit current and internal damage. The increase in resistance can be suppressed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG. 1st
The figure shows a flat fluorocarbon/lithium organic electrolyte battery. In the figure, 1 is a battery case made of stainless steel;
2 is a sealing plate made of the same material, and 3 is a negative electrode active material made of a lithium sheet, which is press-bonded to the sealing plate 2. 4 is a positive electrode current collector made of titanium, which is spot welded to the inner surface of the case 1.

No. 6 was prepared by mixing 5 parts by weight of each of a positive electrode mixture and a fluorocarbon binder as an active material, and molding the mixture into a pellet shape. 6 is a separator made of polypropylene nonwoven fabric,
The electrolyte used was γ-butyrolactone and lithium borofluoride dissolved in 1 mole/β in 1,2 dimethoxyethane. These battery members were used in case 1. After loading into the sealing plate 2, the ends of the case were caulked and sealed via the polypropylene backing 7, and each battery was sealed to form a flat battery with a diameter of 23 m, a thickness of 2, and a weight of 120 mAh. Average value of short circuit current (1), 1sK at 20℃
The following table shows the discharge duration under Ω load (I[), the degree of voltage drop at the beginning of discharge (III), and the average internal impedance after storage at 80°C for one month.

As shown in the table, among the batteries to which the activated carbon of the present invention was added, C- and -G had a short circuit current value of 20% compared to the conventional battery A.
It has increased by ~30%. Furthermore, the internal impedance after storage is small, and it can be said that the storage characteristics are stable. The amount of activated carbon added is 0. 0, 1 which is less than Oo3”/mJi-h
Battery B, in which part by weight was added, did not provide sufficient effects.

On the other hand, Battery H with 10i parts added, which is 0.06"/nAh or more, is good in terms of current and storage. The time will become shorter.

Therefore, the effective range is 0.003 to 0.06
"Zth. More preferably, the amount of activated carbon added to batteries D to F is in the range of about 9.01 to 0.0351 per capacity.

Among these batteries, conventional battery A that does not contain activated carbon
FIG. 2 shows a discharge curve when the battery of the present invention was discharged at 20"C with a resistance of 15 to .OMEGA. as a load.

As shown in the figure, the voltage drop in battery cells at the beginning of discharge is small;
It can be seen that the discharge curve is more flat.

In addition, in the example, activated carbon was added to the positive electrode mixture, but between the separator 6 and the positive electrode mixture 5 or between the case 1 and the positive electrode mixture 5.
A similar effect was obtained even if the addition was made during the period.

In addition, although the example deals with a battery that uses carbon heptadide as the positive electrode active material, organic electrolyte batteries that use metal oxides such as manganese dioxide or copper oxide as the positive electrode active material can also produce a large current. The result was obtained.

Effects of the Invention As is clear from the above description, the battery of the present invention in which activated carbon is added can draw a large current and withstand applications with heavy loads. Furthermore, there is little increase in internal impedance due to storage in a high-temperature atmosphere, and long-term reliability can be ensured.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a battery in an embodiment of the present invention, and FIG.
The figure shows the discharge curves of a battery according to an embodiment of the present invention and a conventional battery at 20"C and a load of 15Ω. 1. Case, 2. Sealing plate. , 3...
...Negative electrode, 4...Positive electrode current collector, 5...
... Positive electrode mixture, 6 ... Separator, 7 ...
...Insulated banking.

Claims (2)

[Claims] (1) A battery that uses an alkali metal as the negative electrode active material, a metal oxide or carbon fluoride as the positive electrode active material, and an inorganic electrolyte dissolved in an organic solvent as the electrolyte. An organic electrolyte battery characterized by the addition of activated carbon. (2) The organic electrolyte battery according to claim 1, wherein the amount of activated carbon added to the battery is 0.003 mg to 0.06 mg per 1 mAh of electric capacity of the positive electrode.