JPS63307668A - Nonaqueous electrolyte cell - Google Patents

Abstract

PURPOSE:To prevent the rise of the internal resistance after storage by using lithium as the negative electrode active material and cupric oxide as the positive electrode active material and adding acetylacetone aluminum to a nonaqueous electrolyte. CONSTITUTION:A negative electrode 4 using lithium as the active material, a nonaqueous electrolyte, and a positive electrode 1 using cupric oxide as the active material are provided. Acetylacetone aluminum is added to the nonaqueous electrolyte. Aluminum ions are deposited on the surface of the lithium negative electrode 4 to form an aluminum film, the reaction between the lithium negative electrode 4 and moisture is suppressed by the existence of this aluminum film, and the deposition of metal copper on the surface of the lithium negative electrode 4 is suppressed. The rise of the internal resistance is thereby suppressed.

Description

Detailed Description of the Invention A. Field of Industrial Application The present invention relates to a nonaqueous electrolyte battery comprising a negative electrode using lithium as an active material, a nonaqueous electrolyte, and a positive electrode using cupric oxide as an active material. It is related to.

Conventional technology Non-aqueous electrolyte batteries using lithium as an active material have the advantage of having high energy density and low self-discharge. If cupric oxide is used as the positive electrode active material, the electric voltage will be reduced to about TSVA, and it has the advantage of being compatible with existing alkaline batteries, mercury batteries, silver batteries, etc., which is attracting attention. ing.

However, when this type of battery is stored, moisture enters the battery and an oxide film is formed on the surface of the lithium negative electrode, and metal copper, which is a reaction product of the positive electrode dissolved in the electrolyte, is deposited on the surface of the lithium negative electrode. The problem is that internal resistance increases and battery capacity decreases.

Problems to be Solved by the Invention The present invention aims to improve the storage characteristics of a nonaqueous electrolyte battery that uses lithium as a negative electrode active material and cupric oxide as a positive electrode active material.

20 Means for Solving the Problems Aluminum acetylacetonate is added to the non-aqueous electrolyte. The amount of aluminum acetylacetonate added is preferably in the range of 001 to CL50 mol/l based on the non-aqueous electrolyte.

When aluminum acetylacetonate is dissolved in an electrolytic solution, aluminum ions precipitate on the surface of the lithium negative electrode to form an aluminum film, and the presence of this aluminum film suppresses the reaction between the silium negative electrode and water. At the same time, precipitation of metallic copper on the surface of the lithium negative electrode is suppressed, and an increase in internal resistance is suppressed.

The positive electrode of the example was made of commercially available special grade 2nd oxide @90% by weight, approximately 5% by weight of graphite as a conductive agent, and 5% by weight of fluororesin powder as a binder.
After adding and mixing the respective weights*, this mixture is weighed approximately 2 tons/
A molded body having a diameter of 15, QW, and thickness tlls was obtained by placing the molded body under pressure at a pressure of -, and this molded body was heat-treated at a temperature of 200 to 500°C.

For the negative electrode, a lithium plate was compressed to a thickness of about α6M, and this lithium rolled plate was made with a diameter of 15.01 mm. It is a punched piece.

The electrolyte was a mixed solvent of propylene carbonate and 1.2 dimethoxyethane with t-1 lithium perchlorate.
-etblI! A polypropylene nonwoven fabric was used as a separator, and the diameter was 2α01L.
A battery (4) of the present invention having a thickness of 2.5M and a thickness of 2.5M was prepared.

FIG. 1 shows a longitudinal cross-sectional view of the battery of the present invention (11 is a cupric oxide positive electrode, and the positive electrode ffr is connected through a positive electrode current collector (2).
(It is pressed to the inner bottom surface of the negative electrode can (6). (4) is a lithium negative electrode, which is pressed to the inner bottom surface of the negative electrode can (6) via the negative electrode current collector (5). (7) is a separator. , (81
is an insulating backing, (91 is a positive electrode inner layer.

Next, in order to investigate the superiority f of the battery of the present invention, a comparative battery (f) which was the same as the battery of the present invention except that aluminum acetylacetonate was added to the electrolytic solution was prepared. The battery of the present invention and the comparative battery were prepared by IE Ikeaki, and were pre-discharged to about 5% of the discharge capacity to form completed batteries.

Figure 8g2 shows the change in internal resistance over time when these batteries were stored at a temperature of 60° C. and a humidity of 90%.

It can be seen from FIG. 2 that the increase in internal resistance after storage in the battery (A) of the present invention is suppressed compared to the comparative battery (A).

The reason for this is that in the case of the battery of the present invention, aluminum film acetylacetonate added to the electrolyte solution forms an aluminum film on the surface of the lithium negative electrode, and the presence of this aluminum film causes a reaction between the lithium negative electrode and moisture or a reaction between the lithium negative electrode and the surface of the lithium negative electrode made of metallic copper. This is thought to be because the precipitation of is suppressed.

Incidentally, since the aluminum film on the surface of the lithium negative electrode is easily removed during discharging, there is no problem in the normal discharging reaction.

In addition, Figure 3 shows the internal resistance of the battery after changing the amount of aluminum acetylacetone added and storing it for one month at a temperature of 60°C and 90% m. From Figure 4, the amount of aluminum acetylacetone added is (LO1~0.
It can be seen that a range of 50 is preferable.

As a means of forming an aluminum film on the surface of the lithium negative electrode, for example, aluminum may be vapor-deposited on a separator as disclosed in JP-A No. 61-294756, or as disclosed in U.S. Pat. No. 4.05-886. Methods have been proposed in which aluminum foil is placed on the surface of the negative electrode, but the manufacturing process for these is complicated;
Also, there is no question about the uniformity of the aluminum coating.

In contrast, in the battery of the present invention, an aluminum coating with excellent uniformity can be formed simply by adding it to a non-aqueous electrolyte.

In addition, the anhydrous salt of acetylacetonaluminum as an additive can be sufficiently dehydrated and subjected to segmentation, and is particularly useful in non-aqueous electrolyte batteries.

Effects of the Invention As mentioned above, in a non-aqueous electrolyte battery that uses lithium as a negative electrode active material and cupric oxide as a positive electrode active material, by adding acetylacetonaluminum to the non-aqueous electrolyte, the It is possible to suppress the increase in internal resistance, and its industrial value is extremely large.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of the battery of the present invention, Figure 2 is a diagram showing the relationship between the internal resistance of the battery and storage period, and Figure 5 is a diagram showing the relationship between the addition chamber of aluminum acetylacetonate and the internal resistance of the battery. It is. Hato... Cupric oxide positive electrode, (2;... Positive electrode current collector. (Fan... Positive electrode can, (41... Lithium negative electrode, (51
... Negative electrode current collector, (6)... Before negative electrode, (7)...
・Separator, (8)...Insulating backing, prisoner・
...Battery of the present invention, however)...Comparison battery.

Claims (2)

[Claims] (1) A negative electrode using lithium as an active material, a non-aqueous electrolyte,
1. A non-aqueous electrolyte battery comprising a positive electrode containing cupric oxide as an active material, the non-aqueous electrolyte comprising aluminum acetylacetonate added to the non-aqueous electrolyte. (2) The non-aqueous electrolyte battery according to claim (1), wherein the amount of aluminum acetylacetone added is in the range of 0.01 to 0.50 mol/l relative to the non-aqueous electrolyte.