JPH063736B2 - Non-aqueous solvent battery - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a non-aqueous solvent battery, and more particularly to a non-aqueous solvent battery having an improved electrolytic solution that also serves as a positive electrode active material.

[Technical background of the invention and its problems]

Non-aqueous solvent batteries that use light metals such as lithium, sodium, and aluminum as the negative electrode active material have the characteristics of high energy density, excellent storage characteristics, and a wide operating temperature range. It is often used as a backup power source. Among them, batteries using lithium for the negative electrode and sulfur oxyhalides such as thionyl chloride (SOCl ₂ ) and sulfuryl chloride (SO ₂ Cl ₂ ) as the positive electrode active material are attracting attention because of their particularly high energy density. . Such a battery has a positive electrode composed of carbon and a metal current collector and generally dissolves a Lewis acid such as aluminum chloride (AlCl ₃ ) or aluminum bromide (AlBr ₃ ) and a Lewis base such as lithium chloride or lithium bromide. Liquid sulfur oxyhalide is used as the electrolyte. Therefore, the liquid oxyhalide serves as both the positive electrode active material and the electrolytic solution, and by using a positive electrode having an appropriate shape, a battery having excellent high rate discharge characteristics can be expected.

By the way, in the battery described above, the oxyhalide of sulfur, which is the positive electrode active material, is in direct contact with lithium of the negative electrode, so that a LiCl film, which is a reaction product, is formed on the surface of the negative electrode lithium. This LiCl film has a function of preventing direct contact between the negative electrode lithium and the oxyhalide, and plays a role of preventing deterioration of battery capacity during storage. However, at the time of discharging, it works as a resistance portion and causes a voltage drop at the initial stage of discharging. The degree of this voltage drop is so small that it can be ignored when the discharge current is very small on the order of μA, but it cannot be ignored when it is a large current discharge.
There is a so-called voltage delay phenomenon, in which after a considerable amount of film growth or during low-temperature discharge, a large voltage drop occurs with the start of discharge, and it takes a considerable amount of time to recover to a predetermined voltage. It was

For this reason, some proposals have been made to solve the above problems. For example, in Japanese Examined Patent Publication No. 57-37992, the surface of the negative electrode is treated with a homopolymer of vinyl chloride or vinylidene chloride or a copolymer of vinyl chloride and vinyl acetate. Coating with a vinyl polymer such as a polymer is disclosed. However, according to such a method, the voltage delay phenomenon is remarkably improved, but when the battery is stored at high temperature and then discharged with a large current, it takes a little time to recover the voltage.

[Object of the Invention]

An object of the present invention is to provide a non-aqueous solvent battery having a small voltage drop even in the initial stage of large current discharge, a short voltage recovery time, and excellent discharge characteristics.

[Outline of Invention]

The present invention provides a non-aqueous solvent battery composed of a negative electrode composed of a light metal such as lithium, a positive electrode containing carbon as a main constituent material, and an electrolytic solution containing sulfur oxyhalide as a main component and also serving as a positive electrode active material. A copolymer of vinyl chloride and vinylidene chloride is added to the electrolytic solution. Thus, the battery in which the copolymer of vinyl chloride and vinylidene chloride is present in the electrolytic solution does not show a large voltage drop even if a large current is applied after storage, and the voltage recovery time is short. In this case, the degree of shortening of the voltage recovery time is remarkably higher than that of a battery in which a homopolymer such as vinyl chloride or vinylidene chloride and a mixture thereof, or a vinyl polymer such as vinyl chloride-vinyl acetate copolymer is added to the electrolytic solution. Are better.

The content of the vinyl chloride-vinylidene chloride copolymer in the electrolytic solution is preferably in the range of 0.2 to 10 g / l. The reason for this is that when the content of the copolymer is less than 0.2 g / l, the suppression of voltage drop cannot be sufficiently exhibited, but when the amount exceeds 10 g / l, the effect is almost zero. Not only does it not increase, but the discharge capacity of the battery may decrease.

The vinyl chloride-vinylidene chloride copolymer used in the present invention has a weight ratio of vinyl chloride and vinylidene chloride of 95: 5-1.
It is desirable that the range is 0 to 90, and more preferably 95: 5 to 50:50.

Embodiments of the Invention Embodiments of the present invention will be described below with reference to the drawings.

Example 1 in the figure is, for example, a step with an open upper surface that also serves as a negative electrode terminal.
It is a bottomed cylindrical can body made of stainless steel. Inner surface of this can body 1
A cylindrical negative electrode 2 made of metallic lithium is pressure-bonded to the
It Inside the can body 1 inside the negative electrode 2, tubular stainless steel is used.
A cylindrical porous carbon layer is pressure bonded to the outside of the metal current collector 3 of the net body.
Structured positive electrode56 made of non-woven glass
₁, 6_TwoIt is provided through. The positive electrode5
Is, for example, commercially available acetylene black and polytetraflu
Mix with oloethylene and mix this kneaded product with a stainless steel net.
A circle with the metal collector 3 of the body so that the collector is inside
After being formed into a tubular shape, it is dried under vacuum at 150 ° C and then mixed.
It is produced by forming the paste into the porous carbon layer 4.

Further, wherein the positive electrode 5 above the can body 1, insulating paper 7 is provided with a hole in the center that is supported by the separator _61. A metal top 8 is sealed by laser welding or the like in the upper surface opening of the can body 1, and a pipe-shaped positive electrode terminal 10 is provided with a glass sealing material 11 in a hole 9 at the center of the metal top 8. It is electrically insulated and fixed to the metal top 8 via. The lower end of the positive electrode terminal 10 is connected to the metal current collector 3 of the positive electrode 5 via a lead wire 12. Then, the electrolytic solution 13 injected from the pipe-shaped positive electrode terminal 10 is accommodated in the can body 1. This electrolytic solution 13 is a commercially available solution of vinyl chloride-vinylidene chloride copolymer (copolymerization) in a solution prepared by dissolving 1.5 mol / mol of aluminum chloride (AlCl ₃ ) and lithium chloride (LiCl) in thionyl chloride (SOCl ₂ ). Ratio 80:20) to 2.5 /
It was added. The pipe-shaped positive electrode terminal 10
For example, a needle body 14 made of stainless steel is inserted into the positive electrode terminal 10 by laser welding the tip of the terminal 10 and the inserted needle body 14.

Comparative Example 1 A battery having the same structure as that of the example was assembled except that a 1.5 mol / concentration AlCl ₃ / LiCl system containing no vinyl chloride-vinylidene chloride copolymer was used as the electrolytic solution.

Comparative Example 2 A battery having the same structure as that of the example was assembled except that the electrolyte solution used was 1.5 mol / concentration of AlCl ₃ / LiCl system containing 2.5 g of vinyl chloride homopolymer / addition.

Comparative Example 3 A battery having the same structure as that of the example was assembled, except that the electrolyte solution used was an AlCl ₃ / LiCl system having a concentration of 1.5 mol / concentration containing 2.5 g of a vinylidene chloride homopolymer / addition.

Comparative Example 4 As an electrolytic solution, 2.5 g of a mixed polymer prepared by mixing a vinyl chloride homopolymer and a vinylidene chloride homopolymer in a weight ratio of 80:20 was added, and 1.5 mol / concentration of AlCl ₃ / L was added.
A battery having the same structure as that of the example was assembled except that the iCl type was used.

Comparative Example 5 As an electrolytic solution, a vinyl chloride-vinyl acetate copolymer (copolymerization ratio 86:14) of 2.5 g / 1.5 mol / concentration was added.
A battery having the same structure as that of the example was assembled except that an AlCl ₃ / LiCl system was used.

Then, regarding the batteries of this example and Comparative Examples 1 to 5,
After assembling, the product was stored at 60 ° C for 20 days, then discharged with a constant resistance of 30Ω, and the minimum voltage at the start of discharge and the voltage were 2.
The time to return to 5 V, and the average operating voltage and discharge capacity were measured. The results are shown in the table below.

As is clear from the above, the battery containing the vinyl chloride-vinylidene chloride copolymer in the electrolytic solution has a smaller initial voltage drop than the conventional battery, and has a short voltage recovery time, and further has a discharge capacity. It turns out that also improves.

〔The invention's effect〕

As described in detail above, according to the present invention, a non-aqueous solvent battery having excellent discharge characteristics, such as suppressing a voltage drop even at the initial stage of a large current discharge, shortening a voltage recovery time, and improving a discharge capacity, can be provided. Can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a non-aqueous solvent battery showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Can body, 2 ... Negative electrode, 3 ... Metal collector, 4 ... Porous carbon layer, 5 ... Positive electrode, 6 ₁ , 6 ₂ ... Separator, 8 ... Metal top, 10 ... Pipe-shaped positive electrode terminal, 13 ... Electrolysis liquid.

Claims (1)

[Claims] 1. A non-electrode comprising a negative electrode composed of a light metal such as lithium, sodium and aluminum, a positive electrode containing carbon as a main constituent material, and an electrolytic solution containing sulfur oxyhalide as a main component and also serving as a positive electrode active material. In a water solvent battery,
A non-aqueous solvent battery, wherein a copolymer of vinyl chloride and vinylidene chloride is added to the electrolytic solution.