JPH0782841B2 - Non-aqueous electrolyte battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery provided with a negative electrode using lithium or a lithium alloy as an active material, a positive electrode, and a non-aqueous electrolyte containing a solvent and a solute. It is about.

(B) Conventional technology This type of battery has the advantages of high energy density per unit volume and low self-discharge.

By the way, lithium perchlorate is generally used as a solute that constitutes the electrolytic solution, but when lithium perchlorate is used, low-temperature characteristics are difficult, and lithium perchlorate has a very high oxidizing power. Therefore, there is a problem that the organic solvent is oxidized.

Therefore, for example, JP-A-58-66264 and JP-A-58-163
When a lithium salt containing fluorine such as lithium trifluoromethanesulfonate, lithium hexafluorophosphate or lithium tetrafluoroborate disclosed in Japanese Patent No. 176 is used as a solute, the low temperature characteristics can be improved and the fluorine content can be improved. Since the lithium salt containing is not oxidative, the problem of oxidizing the organic solvent can be solved.

C. Problems to be Solved by the Invention However, when a lithium salt containing fluorine is used as a solute,
Moreover, as disclosed in, for example, Japanese Examined Patent Publication No. 55-15067, when the nickel which is generally used as a positive electrode constituent member of a non-aqueous electrolyte battery is combined with stainless steel containing almost no nickel, the positive electrode constituent member is corroded. However, there is a problem that the positive electrode constituent member dissolved in the electrolytic solution is deposited on the surface of the negative electrode, causing a voltage drop, a decrease in discharge capacity, etc., and degrading the storage characteristics of the battery.

D. Means for solving the problem In a non-aqueous electrolyte battery that uses a lithium salt containing fluorine as a solute that constitutes the non-aqueous electrolyte, use nickel or nickel alloy containing 30% by weight or more of nickel as a positive electrode constituent member. It is characterized by

It is considered that the corrosion of the positive electrode constituent member when the lithium salt containing fluorine is used as the solute is due to the destruction of the passive chromium oxide film formed on the surface of the stainless steel as the positive electrode constituent member. Then, the lithium salt containing fluorine has no oxidizing action, and therefore the corrosion phenomenon progresses.

However, when nickel or a nickel alloy containing 30% by weight or more of nickel is used as the positive electrode constituent member like the battery of the present invention, a passive oxide film is more likely to be formed in nickel than in the case of chromium, and a chromium oxide film Since the nickel oxide film is more stable in the non-aqueous electrolyte solution containing the lithium salt containing fluorine as a solute than in the case, corrosion of the positive electrode component made of nickel or nickel alloy containing a large amount of nickel is suppressed. Become.

F. Embodiments The first embodiment of the present invention will be described below with reference to the drawings.
The figure shows a longitudinal sectional view of the battery of the present invention. In the figure, (1) is a negative electrode obtained by punching a rolled lithium plate into a predetermined shape, which is press-bonded to the inner bottom surface of a negative electrode can (2) made of stainless steel (SUS304). ing. (3) is a mixture of manganese dioxide as an active material, carbon powder as a conductive agent and fluororesin powder as a binder in a weight ratio of 85: 10: 5, and the mixture is pressure-molded and then 250-350. A positive electrode obtained by heat treatment at ° C is pressed against the inner bottom surface of the positive electrode can (4), which is the gist of the present invention. Here, stainless steel containing 30% by weight of nickel and 20% by weight of chromium was used as the constituent member of the positive electrode can.

In addition, (5) is a separator made of polypropylene non-woven fabric, and the separator is a non-aqueous electrolysis in which 1 mol / mol of lithium trifluoromethanesulfonate as a solute is dissolved in an equal volume mixed solvent of propylene carbonate and 1.2 dimethoxyethane. Liquid is impregnated. (6) is an insulating packing. The battery dimensions were 20.0 mm in diameter, 0.25 mm in thickness, and 120 mAH in battery capacity. This battery of the present invention is referred to as (A).

Next, for comparison, comparative batteries (B) and (C) similar to the batteries of the present invention except that the constituent members of the positive electrode can differ as shown in Table 1 were prepared.

2 and 3 show discharge characteristic comparison diagrams of the battery of the present invention and the comparative battery, and FIG. 2 is a discharge characteristic diagram when the battery is immediately discharged at a constant resistance of 500 Ω at room temperature after assembly. FIG. 3 is a discharge characteristic diagram when the battery was stored at 60 ° C. for 3 months and then discharged at a constant resistance of 500Ω at room temperature.

As is clear from FIG. 2 and FIG. 3, there is no difference in the characteristics due to the difference in the positive electrode can constituent members in the discharge after the battery is assembled, but a remarkable difference is recognized in the discharge after the high temperature storage.

Table 2 shows the measurement results of the internal impedance of each battery before storage and after storage at high temperature. The measurement was performed at a frequency of 1 KHz.

As is clear from the results in Table 2, the comparative battery (B)
In (C), the internal impedance increases after storage, whereas in the battery (A) of the present invention, the internal impedance hardly increases even after storage.

Moreover, when the battery after storage was electrolyzed, a comparative battery (B)
In (C), the surface of the lithium negative electrode was discolored black, but in the battery (A) of the present invention, such a phenomenon was not observed.

Furthermore, when observing the positive electrode can after storage with a metallurgical microscope,
In the case of the comparative batteries (B) and (C), considerable pitting corrosion was observed, but in the case of the batteries (A) of the present invention, almost no corrosion was observed.

Although only the case of the positive electrode canister was illustrated as the positive electrode constituent member in disclosing the present invention, the present invention is not limited to this, and it is obvious that the present invention can be applied to these when using a positive electrode current collector or a positive electrode canister. is there.

As described above, in the non-aqueous electrolyte battery using the lithium salt containing fluorine as the solute constituting the non-aqueous electrolyte, as described above, nickel or nickel alloy containing 30% by weight or more of nickel is used as the positive electrode constituent member. By
The corrosion phenomenon of the positive electrode constituent member, which is a problem peculiar to this type of battery, can be suppressed, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of the battery of the present invention, FIGS. 2 and 3 show the relationship between battery voltage and discharge time, FIG. 2 is an initial discharge characteristic diagram, and FIG. 3 is storage at 60 ° C. for 3 months. It is a discharge characteristic diagram after it is done. (1) …… Lithium negative electrode, (2) …… Negative electrode can, (3)…
… Positive electrode, (4) …… Positive electrode can, (5) …… Separator,
(6) ... Insulating packing.

Claims (1)

[Claims] 1. A negative electrode comprising lithium or a lithium alloy as an active material, a positive electrode, and a non-aqueous electrolyte comprising a solvent and a solute composed of a lithium salt containing fluorine. A non-aqueous electrolyte battery comprising nickel or a nickel alloy containing 30% by weight or more of nickel.