JPS60200465A - Method of manufacturing electrolyte for nonaqueous- solvent cell - Google Patents

Abstract

PURPOSE:To provide a nonaqueous-solvent cell excellent in initial discharge characteristics, by using an electrolyte manufactured by adding lithium to a solution containing thionyl chloride as the main constituent, then stirring the mixture and leaving it quiet at the room temperature and thereafter filtering the mixture, to reduce the voltage drop of the cell even at the initial stage of large-current discharge. CONSTITUTION:1.2mol/l of AlCl3 is dissolved in SOCl2. 1.2mol/l of LiCl is then dissolved in the solution. After that, about 2g of lithium pieces, each of which has a size of 10mm. (length), 10mm. (width) and 0.5mm. (thickness), are added to 100ml of the solution. This mixture is stirred for 3 days. The mixture is thereafter filtered to remove the liquid of the lithium pieces. The filtered liquid is used as electrolyte to assemble a thionyl-chloride cell. When the cell is discharged through a fixed resistance of 30OMEGA, it is understood that the cell A which is an embodiment of the present invention undergoes a smaller voltage drop at the initial stage of discharge than a cell B as a comparison object and is therefore excellent in initial discharge characteristics, as shown in the drawing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for producing an electrolyte for a non-aqueous battery, and particularly to a method for producing an electrolyte for a thionyl chloride battery.

[Technical background of the invention and its problems]

Nonaqueous solvent batteries that use lithium or sodium as negative electrode active materials have high energy density, excellent storage characteristics, and a wide operating temperature range, and are often used as backup power sources for calculators, watches, and memories. Such a battery consists of a negative electrode, an electrolyte, and a positive electrode.
Generally, an alkali metal such as lithium or sodium is used as the negative electrode, and propylene carbonate or r-
A solution prepared by dissolving electrolytic materials such as lithium perchlorate and lithium fluoroborate in a non-aqueous solvent such as butyrolactone and dimethoxyethane is used, and manganese dioxide, graphite fluoride, etc. are used as the positive electrode, respectively.

The so-called lithium-thionyl chloride-based battery, which uses lithium in the negative electrode and thionyl chloride (5OCzz) as the main positive electrode active material, is attracting attention because of its high energy density.

These cells have a positive electrode consisting of a porous carbon body and a metal current collector, and typically contain lithium chloride (LiCI) and aluminum chloride (HTCLS) dissolved in thionyl chloride (SOC/2) used as the electrolyte. ing.

Therefore, 5ocz serves both as a positive electrode active material and as an electrolyte.

By the way, in the above-mentioned lithium-thionyl chloride battery, since the positive electrode active material 5OCf is in direct contact with the negative electrode lithium, the reaction product LICI! is deposited on the negative electrode lithium surface.
A film is formed. The generated LICJ film has the function of preventing direct contact between the negative electrode lithium and SOCl2,
It serves to prevent battery capacity deterioration during storage. However, during discharge, it acts as a resistance component and causes a voltage drop in the early stage of discharge. Furthermore, since the LtCJ film peels off due to discharge and the voltage recovers accordingly, there is no problem in the middle or late stage of discharge, but a large voltage drop is induced in the early stage of discharge, especially during large current discharge. lead to shortcomings.

[Purpose of the invention]

The present invention aims to provide a method for producing an fC electrolyte suitable for non-aqueous solvent batteries that can suppress a significant voltage drop at the initial stage of large current discharge.

[Summary of the invention]

The present inventors produced an electrolytic solution by adding all lithium pieces or lithium powder to a solution containing thionyl chloride as a main component, stirring it at room temperature, letting it stand, and then pouring it into a trap. discovered a non-aqueous solvent battery tray that can prevent significant voltage drop during large current discharge by housing a lithium negative electrode and a positive electrode mainly composed of porous carbon in a can with a separator in between. . The reason why a non-aqueous solvent battery with excellent fc% properties can be obtained by using such an electrolytic solution is presumed to be due to the following reason.

That is, one of the mechanisms by which a vc I', lC/film is formed on the surface of the lithium negative electrode is direct contact between the lithium negative electrode and 5OCt, but 5OCt, which also serves as a solvent for the electrolyte, 2
When only 5 oz2 is brought into contact with lithium without dissolving the electrolyte, the rate of film formation is slower in the axial direction than when lithium is brought into contact with an electrolyte solution in which the electrolyte is dissolved. Are known. This indicates that dissolving in the electrolyte -55OCI2 has some effect on the lithium surface.
The reason for this is thought to be water contained in the electrolyte. In many cases, the electrolyte in lithium thionichloride)V cells is klcl, and LiCl! However, these reagents are highly hygroscopic and it is extremely difficult to dry them completely.
However, in practical use, some water will be mixed in. Therefore, the mixed water causes AJ(OH)Cl to enter the electrolyte.
, is dissolved, and this A/(0)1)CI! It is thought that 2 reacts with lithium and forms a LiCJ film on the lithium surface. For this reason, by adding lithium pieces or lithium powder to a solution containing thionyl chloride as the main component and stirring it at room temperature, the above-mentioned! M(OH)C
It is presumed that J is quickly removed by reacting with lithium pieces and the like, and that by using it as a % solution after filtration, it is possible to suppress the formation of an LICJ film on the surface of the lithium negative electrode.

[Embodiments of the invention]

The present invention will be explained in detail below.

Example First, A7CI on 5ocz2! s'fr: l, 2
rnol! // Dissolve and change LICI! 'lc1.
2moI! /I! After dissolving fc, the size is 10XIOXo,5+i for the solution w t 100m7
Approximately 2 g of +++ lithium pieces were added in total, stirred for 3 days, and then passed through the mouth to remove the lithium pieces to produce an electrolytic solution.

Next, the obtained electrolyte was used to assemble an AA size thionyl chloride battery as shown in FIG.

1 in the figure is a stainless steel can that also serves as a negative electrode terminal. A cylindrical negative electrode 2 made of metallic lithium is crimped onto the inner peripheral surface of the can 1.

Inside the negative electrode 2, a separator 4 made of, for example, glass fiber non-woven fabric, with a positive electrode 3 disposed inside the negative electrode 2;
The positive electrode 3 is housed through a bottom paper 5 made of the same nonwoven fabric placed near the bottom of the can ◎This positive electrode 3 is made by mixing commercially available acetylene black, polytetrafluoroethylene, and a solvent, and then using this mixture. is formed into a cylindrical shape together with a metal current collector 6 made of a stainless steel net so that the current collector 6 is on the inside, and then dried under a vacuum of 150"0 to form a porous carbon layer. It is produced by

Further, in the can body 1 above the positive electrode 3, an insulating paper 7 supported by the separator 4 and having a hole in the center is disposed. A metal top 8 is sealed to the upper opening of the can body 1 by laser welding or the like. This metal top 8
A hole 9 is opened in the center. This person 9 has a pipe-shaped positive terminal 10 with a metal-glass sealing material 11'f.
It is electrically insulated and fixed to the metal top 8 via c. The lower end of this positive electrode terminal 10 is connected to the metal current collector 6 of the positive electrode 3 via a lead wire 12. An electrolytic solution 13 manufactured by the method described above is injected into the can body 1 through the pipe-shaped positive electrode terminal 10 and accommodated therein. A plug 14 made of, for example, a stainless steel ring is inserted into the pipe-shaped positive terminal 10, and the hole of the positive terminal 10 is sealed by laser welding the tip of the terminal 10 and the inserted plug 14. There is.

Comparative Example An electrolytic solution having the same composition as that of the example was produced except that no lithium pieces were added, and this electrolytic solution was used to perform the above-mentioned 'fc
A thionyl chloride battery with the same structure as the mx diagram was assembled.

After manufacture, the batteries of this example and comparative example were stored at 20° 0 for 3 months and discharged at a constant resistance of 30Ω, resulting in the characteristic diagram shown in FIG. 2. In addition, A in FIG. 2 shows the characteristic line of the battery of this example, and B shows the characteristic line of the battery of the comparative example. As is clear from this figure 2,
It can be seen that by using an electrolytic solution treated with lithium pieces, it is possible to obtain a lithium thionyl chloride battery with a small voltage drop at the initial stage of discharge and excellent initial discharge characteristics.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide a method for producing an electrolytic solution suitable for a non-aqueous solvent battery that suppresses voltage drop even in the early stage of large current discharge and has excellent initial discharge characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a lithium thionyl chloride battery according to an example of the present invention, and FIG. 2 is a diagram showing the discharge characteristics of the battery of this example and the battery of a comparative example at the initial stage of large current discharge. 1... Can body, 2... Negative electrode, 3... Positive electrode, 4...
Separator, 6... Metal current collector, 8... Metal top, 10... Pipe-shaped positive terminal, 13... Electrolyte solution.

Claims (1)

[Claims] A non-aqueous non-aqueous product in which a lithium negative electrode and a positive electrode mainly composed of porous carbon are disposed in a can with a separator interposed therebetween, and an electrolytic solution containing an oxyhalide as a main component and which also serves as a positive electrode active material is housed in the can. In the production of the electrolytic solution for a solvent battery, lithium pieces or lithium powder are added to the solution containing the oxyhalide as a main component, stirred at room temperature, allowed to stand, and then sipped. A method for producing an electrolyte for a non-aqueous battery.