JPH0254626B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvement of an organic electrolyte battery using lithium as a negative electrode active material, and aims to improve storage performance. In organic electrolyte batteries that use an organic solvent for the electrolyte, there is a problem in that the electrolyte is oxidized by the positive electrode active material during storage, resulting in a decrease in discharge performance after storage. In view of such circumstances, the present invention provides an organic electrolyte battery using lithium as a negative electrode active material by adding salicylic acid ester to the electrolyte.
This prevents oxidation of the electrolytic solution and improves storage performance without causing a decline in discharge performance. In the present invention, salicylic acid esters include:
For example, phenyl salicylate, p-octylphenyl salicylate, etc. are used. And these salicylic acid esters are present in the electrolyte at a concentration of 0.02 to 0.5
% (weight %, hereinafter the same) is preferably added.
This is because if the amount of salicylic acid ester added is less than 0.02%, the oxidation prevention effect of the electrolyte will not be sufficient, and if it exceeds 0.5%, the oxidation prevention effect will increase, but the discharge performance will deteriorate, such as a decrease in closed circuit voltage. This is because it occurs. In the organic electrolyte battery of the present invention, as the positive electrode active material, for example, manganese dioxide, iron sulfide, copper sulfide, copper oxide, carbon fluoride, silver chromate, etc. are used, and as the electrolyte, for example, propylene carbonate, γ- butyrolactone, tetrahydrofuran,
A solution in which an electrolyte such as lithium perchlorate or lithium borofluoride is dissolved in a solvent such as 1,2-dimethoxyethane or 1,3-dioxolane alone or in a mixture of two or more is used. Next, the present invention will be explained with reference to Examples. FIG. 1 is a sectional view showing a flat organic electrolyte battery. In the drawing, 1 is a positive electrode, 2 is a stainless steel mesh, and 3 is a positive electrode can that also serves as a positive terminal. 4 is a separator made of polypropylene nonwoven fabric or the like, and 5 is a negative electrode can that also serves as a negative electrode terminal. 6 is a stainless steel mesh spot welded to the inner surface of the negative electrode can 5; 7 is a negative electrode;
is crimped to. 8 is an annular gasket made of synthetic resin such as polypropylene. The positive electrode 1 was prepared by filling a mold with 290 mg of a mixture consisting of 100 parts by weight of manganese dioxide (parts by weight, the same applies hereinafter), 10 parts of phosphorous graphite, and 2 parts of polytetrafluoroethylene, which had been heat-treated at 400°C for 4 hours. , after preforming at 1 t/cm ² , a stainless steel mesh 2 is placed on the preform layer, and a diameter of 16 at 7 t/cm ² is formed.
The negative electrode 7 is made of a lithium plate with a diameter of 14 mm and a thickness of 0.2 mm, and the battery has a diameter of 20 mm and a thickness of 1.6 mm. The electrolyte is a mixed solvent of propylene carbonate and 1,2-dimethoxyethane with a volume ratio of 1:1, in which 1 mole of lithium perchlorate is dissolved, and for the battery, phenyl salicylate is added to this electrolyte. The additives shown in Table 1 were injected, and the injected amount was 75μ for each battery. Table 1 shows the results of measuring the internal resistance (internal resistance at 20°C) of these batteries initially and after storage at 60°C for 20 days. In addition, 80% of the above batteries (before storage)
Table 1 also shows the results of measuring the closed circuit voltage after discharging for 5 seconds at -10°C and 300Ω during % discharge.

【table】

[Table] As shown in Table 1, the addition of phenyl salicylate reduces the increase in internal resistance due to storage, and the effect of adding phenyl salicylate is obvious. Note that if the amount added increases, the closed circuit voltage during heavy load discharge will decrease, so the amount added should be 0.02 to 0.5.
A range of % is preferred.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the organic electrolyte battery of the present invention. 7...Negative pole.

Claims (1)

[Scope of Claims] 1. An organic electrolyte battery using lithium as a negative electrode active material, characterized in that a salicylic acid ester is added to the electrolyte. 2. The organic electrolyte battery according to claim 1, wherein the amount of salicylic acid ester added is 0.02 to 0.5% by weight.