JPH0560231B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention provides a negative electrode that uses light metals such as lithium, sodium, or alloys thereof as an active material, and a negative electrode that uses metal oxides, sulfides, halides, etc. as active materials. The present invention relates to a non-aqueous electrolyte battery including a positive electrode and a non-aqueous electrolyte consisting of a solvent and a solute, and particularly relates to improvements in the non-aqueous electrolyte.

(b) Prior Art Various solvents and solutes have been proposed for constituting the non-aqueous electrolyte used in this type of battery. Specifically, as disclosed in Japanese Patent Publication No. 57-32866, propylene carbonate, γ-butyrolactone, dimethoxyethane, dioxolane, tetrahydrofuran, etc. are used as solvents,
Also, known solutes include lithium perchlorate and lithium borofluoride.

Now, in recent years, as the field of application of this type of battery has expanded, there has been a demand for improvements in battery characteristics, and one of these is the desire to improve high rate discharge characteristics.

Incidentally, from the viewpoints of electrical conductivity and ion diffusion, a solvent suitable for high rate discharge is required to have high conductivity and low viscosity. However, in general, a Western medium with a high dielectric constant has a high viscosity, and a solvent with a low viscosity has a low dielectric constant.

Therefore, it is possible to obtain a solvent having a high dielectric constant and low viscosity by mixing a high viscosity solvent and a low viscosity solvent, but an appropriate mixed solvent has not yet been found. Therefore, conventional non-aqueous electrolyte batteries have had problems with high rate discharge characteristics.

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are to improve the high rate discharge characteristics of non-aqueous electrolyte batteries.

(d) Means for Solving the Problems The present invention uses a mixed solvent containing at least propylene carbonate and 1,2-dichloroethane as a solvent constituting the non-aqueous electrolyte.

(E) Effect A mixed solvent containing at least propylene carbonate and 1,2-dichloroethane causes solute to dissociate more easily than a single solvent or other mixed solvents, and the energy for solute movement decreases, causing negative electrode active material The reaction between the ions and the positive electrode active material is carried out smoothly.

(f) Examples Examples of the present invention will be described in detail below.

Propylene carbonate and 1,2-
A mixed solvent containing dichloroethane and dichloroethane at a mixing ratio of 1:1 is used, and an electrolytic solution is prepared by dissolving 1 mol/mol of lithium perchlorate as a solute in this mixed solvent.

The positive electrode uses manganese dioxide as an active material that has been heat-treated in a temperature range of 350 to 430 degrees Celsius, and this manganese dioxide and
A mixture of carbon powder as a conductive agent and fluororesin powder as a binder in a weight ratio of 85:10:5 was pressure-molded and heat-treated at 250 to 350°C, and the negative electrode was lithium. A battery A of the present invention having a diameter of 20.0 mm, a thickness of 2.5 mm, and a battery capacity of 120 mAH is obtained by punching a rolled plate into a predetermined size. This battery is called A.

Comparative Example Next, in order to examine the superiority of the battery of the present invention, we prepared a comparative battery B using propylene carbonate alone as a solvent, a comparative battery C using 1,2-dichloroethane alone, and a comparative battery C using propylene carbonate and 1,2-dichloroethane alone. Comparative battery D was prepared using a mixed solvent of - dichloroethane at a mixing ratio of 1:1.
Note that the comparative batteries B, C, and D are the same as the examples of the present invention except for the solvent.

Figure 1 shows the discharge characteristics of these batteries when they were discharged at a constant resistance of 500Ω at 25°C. As is clear from FIG. 1, the battery A of the present invention is the comparative battery B,
The high rate discharge characteristics are improved compared to C and D.

FIG. 2 is a diagram showing the relationship between the mixing ratio of the mixed solvent in the battery of the present invention and the discharge capacity of the battery.

(g) Effects of the invention As mentioned above, the gist of the present invention is to use a mixed solvent containing at least propylene carbonate and 1,2-dichloroethane as a solvent, and this mixed solvent tends to dissociate the solute. In addition, since the energy of solute movement is reduced and the reaction between the ions of the negative electrode active material and the positive electrode active material occurs smoothly, a non-aqueous electrolyte battery with excellent high rate discharge characteristics can be obtained. This greatly contributes to expanding the uses of this type of battery.

[Brief explanation of the drawing]

FIG. 1 is a comparison diagram of the high rate discharge characteristics of the battery of the present invention and a comparative battery, and FIG. 2 is a diagram showing the relationship between the mixing ratio of the mixed solvent in the battery of the present invention and the discharge capacity of the battery. A: Batteries of the present invention, B, C, D: Comparative batteries.

Claims (1)

[Claims] 1 A device comprising a negative electrode having a light metal such as lithium or sodium or an alloy thereof as an active material, a positive electrode, and a non-aqueous electrolyte comprising a solvent and a solute, wherein the solvent contains at least propylene carbonate and 1,2 - dichloroethane.