JPH0775165B2 - Non-aqueous solvent battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) 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.

(Prior Art) A non-aqueous solvent battery using at least one light metal such as lithium, sodium, aluminum, potassium, and calcium as a negative electrode active material has a large energy density, excellent storage characteristics, and a wide operating temperature range. Due to its features, it is often used as a backup power source for calculators, clocks, and memories. 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. For this reason,
The liquid oxyhalide serves both as a positive electrode active material and an 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 the battery capacity during storage. But,
It acts as a resistance component during discharge and causes a voltage drop at the beginning of discharge. 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 in the case of large current discharge, especially when stored at high temperature for a long time.
After a considerable amount of LiCl film growth or during low-temperature discharge, a large voltage drop occurs with the start of discharge, and it takes a considerable time to recover the prescribed voltage. there were.

For this reason, some proposals have been made to solve the above problems. For example, JP-A-56-7360 discloses a homopolymer of vinyl chloride or vinylidene chloride or vinyl chloride and vinyl acetate during electrolysis. Dissolving a vinyl-based polymer such as a copolymer with is disclosed.

(Problems to be Solved by the Invention) Although the voltage delay phenomenon is certainly improved by dissolving the vinyl polymer having a chlorine substituent in the electrolytic solution as described above, the electrolytic solution containing only the vinyl polymer is dissolved. When it is used, when the battery is stored for a long period of time, the addition effect of the vinyl polymer is weakened, resulting in a large voltage drop at the start of discharge and a long time until the battery recovers to a predetermined voltage.

The object of the present invention is to solve the above-mentioned problems, to provide a non-aqueous solvent battery in which the voltage drop is small in the early stage of large current discharge, the voltage recovery time is short, and this effect does not deteriorate even after long-term storage of the battery. To do.

[Structure of Invention]

(Means and Actions for Solving Problems) The non-aqueous solvent battery of the present invention comprises a negative electrode composed of at least one light metal such as lithium, sodium, aluminum, potassium and calcium, a positive electrode containing carbon as a main constituent, and sulfur. In a non-aqueous solvent battery composed of an electrolytic solution containing oxyhalide as a main component and also serving as a bioactive material, 0.2 to 10 g of a vinyl polymer having a chlorine substituent is contained in the electrolytic solution.
/ l and tin compound 1-10wt% of the vinyl polymer
% Is added.

The vinyl-based polymer having a chlorine substituent in the present invention,
It mainly refers to homo- or copolymers and mixtures of polymers having a structure represented by the following general formula.

For example, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride copolymer, ethylene-
Examples thereof include vinyl chloride copolymers and vinyl chloride-vinyl acetate copolymers.

The amount of these vinyl-based polymers added to the electrolytic solution is
It is desirable that the amount is 0.2 to 10 g per electrolytic solution, that is, 0.2 to 10 g / percent, and particularly 0.3 to 5 g / percent. This is because when the addition amount of the vinyl-based polymer is less than 0.2 g /, the effect of suppressing the voltage drop cannot be sufficiently exhibited, but when the amount exceeds 10 g /, the effect is hardly increased. Not only that, but on the contrary, the discharge capacity of the battery may decrease.

Further, the tin compound in the present invention means an organic tin compound such as di-t-butyl stannic chloride, di-n-octyltin maleate polymer, di-n-butyltin bismalein ester salt or stannous chloride. , Inorganic tin compounds such as stannic chloride and stannous oxide may be used. The addition amount of these tin compounds may be 1 to 10 wt% of the amount of the vinyl polymer added to the electrolytic solution. If the amount of this tin compound added is less than 1 wt%, the effect of suppressing the voltage drop will not last for a long time, while if it exceeds 10 wt%, the long-term sustainability of the effect will hardly improve, and rather the battery performance May be deteriorated.

In the non-aqueous solvent battery according to the present invention, the effect of improving the voltage delay phenomenon can be maintained for a long time by adding a tin compound to a predetermined amount of the vinyl polymer.
The reason for this is not clear in detail, but it is considered that the above-mentioned effects are exhibited by the small amount of tin compound and the vinyl polymer acting synergistically in the electrolytic solution.

(Example) Hereinafter, the Example of this invention is described with reference to drawings.

Example FIG. 1 is a sectional view showing the structure of a non-aqueous solvent battery in this example and a comparative example.

Reference numeral 1 in the figure denotes a bottomed cylindrical can body made of, for example, stainless steel, the top surface of which also serves as a negative electrode terminal is opened. A cylindrical negative electrode 2 made of metallic lithium is pressure-bonded to the inner surface of the can body 1. The negative electrode 2 inside of the can body 1, the separator 6 ₁ tubular porous positive electrode 5 having a structure in which crimp the carbon layer 4 on the outer side of the metal current collector 3 of the tubular stainless meshes body is made of glass nonwoven , 6 ₂ are provided. The positive electrode 5 is obtained by mixing, for example, a commercially available acetylene block and polytetrafluoroethylene, and molding the kneaded material together with the metal current collector 3 made of a stainless steel net into a cylindrical shape so that the current collector is inside. After that, it is dried under vacuum at 150 ° C. to form the kneaded material into the porous carbon layer 4.

In addition, in the can body 1 above the positive electrode 5 , the separator
Insulating paper 7 is provided with a hole in supported center 6 _1. A metal top 8 is sealed by laser welding or the like in the upper opening of the can body 1, and a pipe-shaped positive electrode terminal 10 is inserted in a central hole 9 of the metal top 8 via a glass sealing material 11. And is electrically insulated and fixed to the metal top 8. The lower end of the positive electrode terminal 10 is a lead wire 12
It is connected to the metal current collector 3 of the positive electrode 5 via.
Then, the electrolytic solution 13 injected from the pipe-shaped positive electrode terminal 10 is accommodated in the can body 1.

Further, a needle body 14 made of, for example, stainless steel is inserted in the pipe-shaped positive electrode terminal 10, and the needle body 14 inserted into the tip of the terminal 10 is inserted.
The positive electrode terminal 10 is sealed by laser welding of and.

As an example, in an electrolyte solution containing aluminum chloride (AlCl ₃ ) and lithium chloride (LiCl) in an amount of 1.5 mol / mol in thionyl chloride (SOCl ₂ ), the total amount of polyvinyl chloride was 5 w.
90 batteries were prepared using an electrolytic solution in which polyvinyl chloride added with t% di-t-butyl stannic chloride was added and dissolved at a concentration of 2 g /.

Comparative Example 1 Polyvinyl chloride to which di-t-butyl stannic chloride was not added was added and dissolved in an electrolytic solution in which AlCl ₃ and LiCl were dissolved in SOCl ₂ at 1.5 mol / mol, respectively, at a concentration of 2.0 g / Batteries (90 pieces) having the same structure as the example except that the above electrolytic solution was used were assembled.

Comparative Example 2 An electrolytic solution obtained by adding and dissolving di-t-butyl stannic chloride at a concentration of 0.1 g / into an electrolytic solution in which AlCl ₃ and LiCl were dissolved in SOCl ₂ at 1.5 mol / mol, respectively was used. Other than that, batteries (90 pieces) having the same structure as the example were assembled.

Comparative Example 3 In an electrolyte solution in which AlCl ₃ and LiCl were dissolved in SOCl ₂ at 1.5 mol / mol, 0.5 wt% of di-t-based on the total amount of polyvinyl chloride was used.
2 g of polyvinyl chloride added with butyl stannic chloride
90 batteries were prepared using the electrolyte solution added and dissolved at the concentration of.

Comparative Example 4 ₂ g of polyvinyl chloride prepared by adding di-t-butyl stannic chloride in an amount of 12 mol% of the total amount of polyvinyl chloride in an electrolyte solution in which AlCl ₃ and LiCl were dissolved in SOCl ₂ at 1.5 mol / mol, respectively. 90 batteries were prepared using an electrolyte solution added and dissolved at a concentration of /.

Comparative Example 5 Polyvinyl chloride containing 5 wt% S ₂ Cl ₂ of polyvinyl chloride was added at a concentration of 2 g / into an electrolyte solution in which AlCl ₃ and LiCl were dissolved in SOCl ₂ at 1.5 mol / mol. 90 batteries were prepared using the dissolved electrolyte.

Then, after assembling the batteries of this example and Comparative Examples 1 to 5 at 20 ° C., 30 pieces were taken out after 6 months, 12 months, and 24 months, respectively, and constant resistance discharge of 30Ω was performed.
The time until the voltage returned to 2.5 V after the start of discharge, the average operating voltage and the discharge capacity were measured.

The results are shown in Table 1.

As is clear from Table 1, the batteries of Examples in which both di-t-butyl stannic chloride and polyvinyl chloride were added to the electrolytic solution did not contain di-t-butyl stannic chloride, It can be seen that the voltage recovery time at the start of discharge is shorter than that of the battery of Comparative Example 1 in which only polyvinyl chloride is added. This difference in voltage recovery time becomes more remarkable as the storage period becomes longer. Further, it can be seen that the battery of the example has a remarkably short voltage recovery time at the start of discharge as compared with the battery of the comparative example 2 in which only di-t-butyl stannic chloride is added. Furthermore,
Compared with the batteries of Comparative Examples 1 and 2, the batteries of Examples did not show a large voltage drop at the start of discharge even when discharged with a large current after storage, had a large average operating voltage and discharge capacity, and were hardly deteriorated by long-term storage. Not really. In addition to the above-mentioned effects, the battery of the present invention has excellent discharge characteristics at low temperatures and little capacity deterioration due to long-term storage at low temperatures.

〔The invention's effect〕

As described in detail above, according to the present invention, a non-aqueous solvent having excellent discharge characteristics after long-term storage, such as short voltage recovery time at the beginning of large current discharge and suppression of long-term deterioration of discharge voltage and discharge capacity. You can get a battery.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of the structure of a non-aqueous solvent battery. 1 ... Can body, 2 ... Negative electrode, 3 ... Metal current collector, 4 ... Porous carbon layer, 5 ... Positive electrode, 6 ₁ , 6 ₂ ... Separator, 8 ...
… Metal top, 10 …… Pipe-shaped positive electrode terminal, 13 …… Electrolyte.

Claims (1)

[Claims] 1. A negative electrode composed of at least one of light metals such as lithium, sodium, aluminum, potassium, and calcium, 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 non-aqueous solvent battery composed of, 0.2 to 10 g / l of a vinyl polymer having a chlorine substituent and a tin compound are added to the electrolyte solution in an amount of 1 to 10 wt% of the vinyl polymer. Non-aqueous solvent battery.