JPH0521072A - Inorganic non-aqueous electrolyte battery - Google Patents

Abstract

(57) [Summary] [Objective] To provide an inorganic non-aqueous electrolyte battery in which the voltage drop in the initial stage of discharge is small. In an inorganic non-aqueous electrolyte battery in which thionyl chloride also serves as a positive electrode active material and a solvent for an electrolyte solution, AlCl ₃ or LiCl and AlCl ₃ having a higher concentration than the above LiCl are used as electrolytes in the electrolyte solution, and Contains sulfuryl chloride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic non-aqueous electrolyte battery in which thionyl chloride as a positive electrode active material also serves as a solvent for an electrolyte.

[0002]

2. Description of the Related Art Inorganic non-aqueous electrolysis in which thionyl chloride is used as a positive electrode active material, an alkali metal or the like is used as a negative electrode, a carbon porous molded body is used as a positive electrode, and thionyl chloride as the positive electrode active material also serves as a solvent of an electrolytic solution. Liquid batteries have high energy density,
It has excellent characteristics such as operating at low temperature, has less self-discharge, and has a so-called hermetic seal for sealing, so it has an excellent hermetically sealed state and battery performance is stable over a long period of time. Therefore, it is said that the battery has long-term reliability (for example, “Latest Battery Technology”, Realize Co., Ltd., June 1990).
Issued on the 25th of the month, p173).

By the way, the characteristics of this type of battery will be explained by taking an example of a representative battery, a thionyl chloride-lithium type inorganic non-aqueous electrolyte battery, in this battery thionyl chloride as a positive electrode active material and lithium as a negative electrode. Since it is in direct contact with LiCl (lithium chloride)
A film is formed on the lithium surface of the negative electrode, which suppresses self-discharge during storage of the battery and prevents deterioration of the discharge capacity.

[0004]

However, during discharge,
Since the LiCl coating on the lithium surface of the negative electrode provides resistance,
The voltage drops at the beginning of discharge. In particular, when discharging with a large current, the voltage drop at the initial stage of discharging becomes large, which hinders the normal operation of the device using the battery, which is a serious problem.

Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional inorganic non-aqueous electrolyte battery and to provide an inorganic non-aqueous electrolyte battery with a small voltage drop at the initial stage of discharge.

[0006]

According to the present invention, AlCl ₃ (trihydrate aluminum) is used as an electrolyte of an electrolytic solution without using LiAlCl ₄ (lithium aluminum tetrachloride) which has been widely used in inorganic non-aqueous electrolyte batteries. (Aluminum chloride) or LiCl (lithium chloride) and AlCl ₃ having a higher concentration than the above LiCl, and by containing sulfuryl chloride in the electrolytic solution, the voltage drop at the initial stage of discharge is suppressed, and It has been achieved.

That is, the voltage drop at the initial stage of discharge is due to the fact that the LiCl film on the lithium surface of the negative electrode becomes a resistance at the start of discharge, and discharge can be performed only at a voltage lower than the normal voltage until the LiCl film disappears. When the LiCl concentration in the electrolytic solution is lower than the AlCl ₃ concentration, LiCl and AlCl ₃ try to form LiAlCl ₄ in the electrolytic solution, and the LiCl coating on the lithium surface of the negative electrode dissolves into the electrolytic solution. And the voltage drop at the beginning of discharge is reduced.

However, since the self-discharge of the battery is increased by itself, the sulfuryl chloride is contained in the electrolytic solution to control the thickness of the LiCl film on the lithium surface of the negative electrode to reduce the self-discharge. Of.

The reason why sulfuryl chloride controls the thickness of the LiCl coating on the lithium surface of the negative electrode is that sulfuryl chloride is easier to form a LiCl coating than thionyl chloride. The reaction of thionyl chloride and sulfuryl chloride with respect to lithium is as follows.

First, the reaction between thionyl chloride and lithium is as follows, and the reaction between 4Li + 2SOCl ₂ → 4LiCl + S + SO ₂ sulfuryl chloride and lithium is as follows. 2Li + SO ₂ Cl ₂ → 2LiCl + SO ₂

In the present invention, the concentration of AlCl ₃ in the electrolytic solution is preferably 1 to 1.4 mol / l. When the concentration of AlCl ₃ in the electrolytic solution is lower than 1 mol / l, sufficient conductivity cannot be obtained, and when the concentration of AlCl _{3 in} the electrolytic solution is higher than 1.4 mol / l, Li is generated by discharge.
Since the AlCl ₄ concentration becomes too high, the discharge characteristics deteriorate and the low temperature characteristics deteriorate.

The concentration of LiCl in the electrolytic solution is 0 to 0.
It is preferably 6 mol / l. LiC in electrolyte
When the l concentration is higher than 0.6 mol / l, the LiCl coating on the lithium surface of the negative electrode is less eluted into the electrolytic solution, and the effect of suppressing the voltage drop at the initial stage of discharge cannot be sufficiently exerted.

The concentration of sulfuryl chloride in the electrolytic solution is preferably 5 to 15% by weight or more. When the concentration of sulfuryl chloride in the electrolytic solution is lower than 5% by weight, the effect of controlling the LiCl coating on the lithium surface of the negative electrode is not sufficiently exerted, and when the concentration of sulfuryl chloride in the electrolytic solution becomes higher than 15% by weight. However, the flatness of the closed circuit voltage may be deteriorated or the operating temperature range may be narrowed.

In the battery of the present invention, thionyl chloride is used as the positive electrode active material, and this thionyl chloride is used as the positive electrode active material and also as the solvent of the electrolytic solution.

The electrolytic solution was prepared by adding AlCl _{3 to} this thionyl chloride.
Alternatively, LiCl and AlCl _{3 having a} higher concentration than LiCl
Is prepared by dissolving.

In the present invention, the electrolytic solution contains sulfuryl chloride, but the sulfuryl chloride may be added to the electrolytic solution prepared, or may be added to thionyl chloride at the time of preparing the electrolytic solution. You may.

For the negative electrode, an alkali metal such as lithium, sodium or potassium, an alkaline earth metal such as calcium or magnesium, or an alkali metal alloy such as lithium-calcium or lithium-aluminum is used.

As the separator, a glass fiber non-woven fabric is usually used, but any material other than the glass fiber non-woven fabric may be used as long as it has a resistance to thionyl chloride and a function as a separator, for example, ethylene-tetrafluoroethylene copolymer. A microporous film of a polymer or the like can be used, or a glass fiber non-woven fabric coated with an ethylene-tetrafluoroethylene copolymer can be used.

[0019]

EXAMPLES Next, the present invention will be described more specifically with reference to examples.

Example 1 Lithium chloride-lithium system was used by using lithium as a negative electrode and using as an electrolyte solution thionyl chloride in which 1.2 mol / l of AlCl ₃ was dissolved and 5% by weight of sulfuryl chloride was contained. Then, an AA-type inorganic non-aqueous electrolyte battery having the structure shown in FIG. 1 was produced.

Referring to the battery shown in FIG. 1, reference numeral 1 is a negative electrode, and the negative electrode 1 is formed into a cylindrical shape by pressing a lithium sheet onto the inner peripheral surface of a cylindrical battery case 2 made of stainless steel and having a bottom. Has been done.

Reference numeral 3 is a positive electrode, and this positive electrode 3 comprises a carbon porous molded body whose main constituent material is carbon in which a small amount of polytetrafluoroethylene is added to acetylene black as a binder. Is installed through.

The separator 4 is made of a glass fiber non-woven fabric whose fiber surface is coated with ethylene-tetrafluoroethylene copolymer and has a cylindrical shape.

Reference numeral 5 is an electrolytic solution. This electrolytic solution 5 uses thionyl chloride, which is a positive electrode active material, as a solvent for the electrolytic solution. It is prepared by dissolving AlCl _{3 in} this thionyl chloride, and sulfuryl chloride is added. Contains.

In this battery, since the thionyl chloride of the positive electrode active material also serves as the electrolytic solution solvent as described above, a large amount of electrolytic solution 5 is injected into the battery, unlike other batteries, As can be seen from the fact that thionyl is the positive electrode active material, the positive electrode 3 does not itself react, but the reaction site between the positive electrode active material thionyl chloride and the lithium ions ionized and eluted from the negative electrode 1. Is provided.

Reference numeral 6 is a positive electrode current collector made of a stainless steel rod, 7 is a battery lid, and this battery lid 7 has a body 8, a glass layer 9 and a positive electrode terminal 10, and the body 8 is made of stainless steel. The raised outer peripheral portion is joined to the open end of the battery case 2 by welding.

The glass layer 9 is provided on the inner peripheral surface of the body 8. The glass layer 9 insulates the body 8 and the positive electrode terminal 10 from each other, and the constituent glass is formed on the outer peripheral surface of the body 8.
The inner peripheral surface is fused and the constituent glass is fused to the outer peripheral surface of the positive electrode terminal 10 at the inner peripheral surface to seal between the body 8 and the positive electrode terminal 10.

The positive electrode terminal 10 is made of stainless steel, and a part of it has a pipe shape at the time of battery assembly and is used as an electrolyte injection port. The positive electrode terminal 10 is inserted into the hollow portion after the electrolyte is injected. The upper part of the electric body 6 is welded and sealed.

Reference numeral 11 denotes a bottom insulating material, and this bottom insulating material 11 is made of glass fiber nonwoven fabric and insulates the positive electrode 3 and the battery case 2 which also serves as a negative electrode terminal.

Reference numeral 12 denotes an upper insulating material. This upper insulating material 12 is made of the same glass fiber non-woven fabric as the bottom insulating material 11, and has a body 8 of the battery lid 7 which also serves as the positive electrode 3 and the negative electrode terminal.
Is insulated from.

The battery was assembled as follows. First, a lithium sheet was pressure-bonded to the inner peripheral surface of a bottomed cylindrical battery case 2 to form a negative electrode 1, and the separator 4 was arranged in a cylindrical shape along the inner peripheral surface of the negative electrode 1.

Next, the bottom insulating material 11 is arranged on the bottom of the battery case 2, and the cylindrical positive electrode 3 is provided on the inner peripheral side of the separator 4.
Is inserted, the upper insulating material 12 is arranged on the positive electrode 3, the battery lid 7 is fitted into the opening of the battery case 2, and the outer peripheral portion of the body 8 of the battery lid 7 and the open end of the battery case 2 are connected. Welded and joined with a carbon dioxide laser.

Next, the electrolytic solution is injected into the battery through the pipe portion of the battery lid 7, the positive electrode current collector 6 is inserted into the pipe portion after the electrolytic solution is injected, and the lower end of the positive electrode current collector 6 is attached to the upper insulating material. 12
To reach the inside of the positive electrode 3, and the upper portion of the positive electrode current collector 6 was welded and sealed to the upper end of the pipe portion to configure the positive electrode terminal 10 and the battery was assembled in the state shown in FIG.

Example 2 As an electrolytic solution, 0.6 mol of LiCl was added to thionyl chloride.
/ L and AlCl _{3 in an amount} of 1.2 mol / l and containing sulfuryl chloride in an amount of 5% by weight. A water electrolyte battery was produced.

Comparative Example 1 As an electrolytic solution, 1.2 AlAl ₄ was added to thionyl chloride.
A thionyl chloride-lithium-based AA-type inorganic non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that the solution dissolved in mol / l was used.

The batteries of Examples 1 and 2 and the battery of Comparative Example 1 were discharged at a discharge resistance of 100Ω and the discharge characteristics at the initial stage of discharge were examined. The result is shown in FIG.

As shown in FIG. 2, in the battery of Comparative Example 1 corresponding to the conventional battery, the voltage dropped to 2.55 V at the initial stage of discharge, but in the battery of Example 1, the voltage drop was 3.06 V. The battery of Example 2 had a voltage drop of up to 2.80 V, which was smaller than that of the battery of Comparative Example 1.

[0038]

As described above, according to the present invention, AlCl ₃ or LiCl and the above-mentioned Li are used as the electrolyte of the electrolytic solution.
By using AlCl ₃ having a higher concentration than Cl and including sulfuryl chloride in the electrolytic solution, it was possible to provide an inorganic non-aqueous electrolytic solution battery having a small voltage drop at the initial stage of discharge.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an inorganic non-aqueous electrolyte battery according to the present invention.

FIG. 2 is a diagram showing the discharge characteristics of the batteries of Examples 1 and 2 and the battery of Comparative Example 1 at the initial stage of discharge.

[Explanation of symbols]

1 negative electrode 3 positive electrode 4 separator 5 Electrolyte

Claims (2)

[Claims] 1. Thionyl chloride as a solvent for a positive electrode active material and an electrolytic solution, a negative electrode 1 made of an alkali metal, an alkaline earth metal or an alkali metal alloy, a positive electrode 3 made of a carbon porous molded body, and a separator 4. In an inorganic non-aqueous electrolyte battery having an electrolyte solution 5, AlCl ₃ or LiCl as an electrolyte of the electrolyte solution 5 is used.
And a higher concentration of AlCl ₃ than LiCl, and the electrolytic solution 5 contains sulfuryl chloride, an inorganic non-aqueous electrolytic solution battery. 2. The concentration of AlCl _{3 in} the electrolytic solution 5 is 1 to
The concentration of LiCl is 0 to 0.6 mo at 1.4 mol / l.
The inorganic non-aqueous electrolyte battery according to claim 1, wherein the concentration is 1 / l and the concentration of sulfuryl chloride is 5 to 15% by weight.