JPS63126153A - Organic electrolyte cell - Google Patents

Abstract

PURPOSE:To reduce the carbon powder amount of a conductive material necessary to give the electron conductivity to a positive electrode, to increase the filler active substance amount consequently, and to improve the utilization efficiency of the active substance, by using an active substance which is made by absorbing graphite over the surface of copper oxide and chalcopyrite. CONSTITUTION:An active substance is made by absorbing graphite powder to a copper oxide and chalcopyrite beforehand, and an organic electrolyte cell with a positive electrode 4 which consists of a conductive material of carbon powder and a binder, and a negative electrode 2 which consists of lithium or an alloy mainly of lithium is composed. By absorbing the graphite powder at the surface of the copper oxide and the chalcopyrite, the specific gravity of the cell itself is not almost changed, but the good adhesive property of the graphite powder at the surface and the graphite powder or the carbon black of the conductive material makes a uniform mixing even with a small amount of conductive material. Therefore, the active substance can be increased at the amount of reducing the carbon powder, resulting in an increase of the electric capacity of the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement in an organic electrolyte battery using a mixture of copper oxide and chalcopyrite as a positive electrode active material and lithium or a lithium-based alloy as a negative electrode active material.

BACKGROUND OF THE INVENTION As conventional organic electrolyte batteries, so-called 3V class lithium batteries have been put into practical use, using graphite fluoride, manganese dioxide, thionyl chloride, sulfur dioxide, etc. as positive electrode active materials.

Recently, attention has been paid to the excellent storage properties and leakage resistance of organic electrolyte batteries, and so-called 1.5v class lithium batteries, which are directly compatible with conventional dry batteries, alkaline manganese batteries, silver oxide batteries, etc., have recently been developed. development is underway. Particularly in the field of button-shaped batteries used in small precision electronic devices such as electronic watches and portable calculators, some of them have already been put into practical use. As this type of battery, lithium batteries using copper oxide, iron disulfide, bismuth oxide, lead bismuth oxide, etc. as positive electrode active materials are known. Among these, copper oxide/lithium batteries that use copper oxide as an all-positive electrode active material can be said to be the most promising battery system, as they have large capacity, excellent voltage flatness, and good storage characteristics.

However, this battery system has the drawback that the voltage temporarily drops before the voltage settles to a constant value at the beginning of battery discharge.

As a measure to eliminate this drawback, Japanese Patent Application Laid-Open No. 68-2060
No. 56 proposes the use of chalcopyrite, which has a higher discharge voltage, mixed with copper oxide, which is a positive electrode active material.

The present invention relates to an improvement in a battery using this mixture of copper oxide and chalcobite as the active material of the positive electrode. Generally, this kind of active material is non-conductive, and a suitable conductive material, usually carbon powder, is used. A method is adopted in which the electrodes are mixed to make the electrodes conductive. The carbon powder used as the conductive material must itself have high conductivity, and graphite powder or carbon blank powder is usually used.

Problems to be Solved by the Invention However, since the internal volume of a battery is constant, using carbon powder as a conductive material means that the amount of active material decreases, and the battery's electricity This means that the capacity will decrease. Therefore, it is desirable that the amount of this carbon powder be as small as possible. On the other hand, the specific gravity of graphite powder, which is a carbon powder used as a conductive material in batteries, is about 2.2 mm, although it varies depending on the type, whereas carbon black has a specific gravity of about 1.8 mm. , the specific gravity of copper oxide used as an active material is 6.3, and the specific gravity of chalcopyrite is 4.2. Because of this large difference in specific gravity, in order to give good conductivity to the electrode, it is necessary to use a graphite powder with a specific gravity of 10 to 2.
It is necessary to mix as much as 0% and 8 to 16% as carbon black, which inevitably causes a problem that the electric capacity of the battery decreases.

The object of the present invention is to reduce the amount of carbon powder to be mixed as much as possible, and to obtain a battery with a large electric capacity.

Means for Solving the Problem In order to solve this problem, the present invention uses copper oxide and chalcopyrite l active materials on which graphite powder has been adsorbed in advance, and a positive electrode consisting of carbon powder as a conductive material and a binder. The present invention provides an organic electrolyte battery having a gold negative electrode made of lithium or an alloy consisting entirely of lithium.

Function As mentioned above, the specific gravity of copper oxide, which is an active material, is 6.3 and the specific gravity of chalcopyrite is 4.2, whereas the specific gravity of graphite powder, which is a conductive material, is 2.2, and the specific gravity of carbon blank is 6.3. 1.8, and it can be said that it is essentially impossible to uniformly mix materials with such a difference in specific gravity. In the present invention, by completely adsorbing graphite powder on the surface of copper oxide and chalcopyrite, the specific gravity of the graphite powder itself hardly changes, but good adhesion between the graphite powder on the surface and the graphite powder or carbon black of the conductive material is achieved. This method uses the effect that even a small amount of conductive material can be mixed uniformly due to its properties.

That is, when copper oxide and graphite powder, or chalcopyrite and graphite powder are mixed and stirred under reduced pressure with vibration, the graphite powder easily adsorbs to the surface of the copper oxide or chalcopyrite. Even when a mixture of copper oxide and chalcopyrite is mixed with graphite and stirred under reduced pressure while being vibrated, the graphite is similarly adsorbed onto the surface of each comb. As a result, when this mixture of copper oxide and chalcopyrite is used as a positive electrode active material, when the conventional mixture of copper oxide and chalcopyrite is used, the amount of carbon powder in the conductive material is 1 for graphite.
0 to 20% and 8 to 15% for carbon blank, but 6 to 10% for graphite and 6 for carbon black.
reduced to ~8%. As a result, the amount of active material can be increased by the amount of carbon powder reduced, and the electric capacity of the battery can be increased. It has also been found that in order for graphite to adsorb onto the surface of copper oxide or chalcopyrite, the optimum specific surface area of graphite is 50 to 100 m/g.

Example The present invention will be explained below with reference to Examples.

Example 1 Copper oxide (CuO) and chalcopyrite (CuFeS2)
The active material is a mixture of copper oxide and chalcopyrite, which has been surface-treated to adsorb graphite, and the conductive material graphite powder and the binder tetrafluoroethylene 6.
Aqueous dispersions of fluorinated propylene copolymers were mixed in the proportions shown in Table 1, and after drying, a diameter of 8.
581171. Pressure mold it into a disk shape with a thickness of 0.7 mm, and use it as a positive electrode. Note that the weight ratio of copper oxide and chalcopyrite was 6:4. The theoretical charging amount of electricity for these positive electrodes is also shown in Table 1.

Table 1 Using these positive electrodes, the button-shaped battery shown in FIG. 1 was completely assembled. Let the respective batteries be -fA-E.

In Figure 1, 1 is a sealing plate made of nickel-plated stainless steel, and its inner surface has a diameter of 6.8M and a thickness of 0.
．． A negative electrode 2 made of 75B lithium is pressure-bonded. The theoretical amount of electricity charged in the negative electrode is 56 mAh. 3 is a polypropylene separator, propylene carbonate and 1
．． A solvent mixed with 2-dimethoxyethane at a volume ratio of 1:1 is impregnated with an electrolytic solution in which lithium perchlorate is dissolved at a ratio of 1 mole/β. 4 is the disk-shaped positive electrode, which is further pressure-molded within a nickel-plated stainless steel battery case S. 6 is a gas Kent made of polypropylene. The dimensions of the completed battery are 9.5jLm in diameter.
, to a height of 2.0.

FIG. 2 shows the characteristics of these batteries when discharged at 20'C under a load of 30 Ω, and FIG. 3 shows the characteristics when discharged under a load of 6 Ω.

As is clear from Figure 2, when a mixture of copper oxide and chalcopyrite without surface treatment is used as an active material,
It can be seen that even at a discharge of 20Ω, which is a relatively low load, a battery containing 6% graphite powder as a conductive material has greatly inferior characteristics. On the other hand, in the battery cell of the present invention, which uses a mixture of surface-treated oxidized steel and chalcopyrite as an active material, although the graphite powder as a conductive material accounts for 6%, the conductive material is added to the untreated active material. 10chi, 16% mixed battery B,
It can be seen that it has better characteristics than C.

In addition, when discharging with a load of 5Ω, which is assumed to be a strong load pulse discharge when used in an electronic watch, etc., as shown in Figure 3, it is clear that the battery of the present invention has poor discharge voltage characteristics and active material utilization. , D, and H are located right next to each other.

In other words, even though the same copper oxide and chalcopyrite active materials are used and the battery configuration is the same, there is a large difference due to the effect of adsorbing graphite on the surface of the copper oxide and chalcopyrite. It can be said that there is.

Example 2 A study was conducted with the same battery configuration as in Example 1, but with the conductive material changed to acetylene plaque, which is a type of carbon black. The positive electrode configuration is shown in Table 2.

Table 2 The characteristics of these batteries A' to E' when discharged at 20°C with a load of 30 Ω connected to them as in Example 1 are shown in Figure 4. The characteristics when discharged are shown in the 6th
The figure shows n.

As is clear from FIG. 4, the battery D',! 'Batteries' are superior in terms of voltage characteristics and discharge utilization rate compared to conventional batteries ', B' and C'. Furthermore, in the case of heavy load discharge shown in FIG. 5, the difference is even more remarkable.

In other words, by adsorbing graphite powder on the surface of copper oxide and chalcopyrite active materials, significant improvements in the discharge voltage and amount of electricity of the battery were observed, regardless of the type of conductive carbon powder. .

Effects of the Invention As is clear from the above, according to the present invention, by using as an active material a material in which graphite is completely adsorbed on the surface of copper oxide and chalcopyrite, it is possible to obtain the necessary properties for imparting electronic conductivity to the positive electrode. By reducing the amount of carbon powder in the conductive material, increasing the amount of filled active material, and improving the utilization rate of the active material, we have created a battery with better voltage characteristics and higher capacity density than conventional batteries. This has the effect of being able to provide the following.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a button-shaped battery used in an example of the present invention, and Figures 2 and 3 are comparisons of characteristics between the battery of the present invention and a conventional battery when graphite powder is used as the conductive material in the positive electrode. 4 and 5 are characteristic comparison diagrams between a battery of the present invention and a conventional battery when a carbon blank is used as the conductive material of the positive electrode. 1...Sealing plate, 2...Negative electrode, 3...
...Separator, 4...Positive electrode, 5...
・Case, 6...Gasket. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Sealing plate Z---λ tumor 3---Separator/4-Positive electrode No. 1 Figure 5-Booth B -Cut Suzut Figure 2 θ 5l)l)
7ρθO Genden Ginkanpe) Figure 3 7), 50
/θθ discharge last time (phantom figure 4 0 5θo
10ρ0 Hou J Sakuma ((Ji

Claims (2)

[Claims] (1) Copper oxide (CuO) and chalcopyrite (CuFe)
A positive electrode using a mixture of S_2) as an active material, and a negative electrode using lithium or an alloy mainly composed of lithium as an active material.
An organic electrolyte battery characterized in that the positive electrode is made of copper oxide and chalcopyrite with graphite powder adsorbed on the surface, carbon powder as a conductive material, and a binder. (2) The organic electrolyte battery according to claim 1, wherein the carbon powder of the conductive material is graphite or carbon black.