JPS59209274A - Nonaqueous solvent battery - Google Patents

Abstract

PURPOSE:To prevent voltage drop even in an initial stage of high rate discharge by adding a specified molar ratio of aluminium chloride and lithium carbonate to electrolyte also acting as positive active material mainly comprising oxyhalide of sulfur. CONSTITUTION:A negative electrode 2 comprising at least one of lithium, sodium, and aluminium and a positive electrode 3 mainly comprising porous carbon are accommodated in a can 1 with a separator 4 interposed, and electrolyte also acting as positive active material mainly comprising oxyhalide of sulfur is placed in the can 1. Electrolyte in which a molar ratio of lithium carbonate to aluminium chloride is 0.5 or more is used. Thereby, growth of a LiCl film generating on the lithium negative electrode is suppressed, and when the battery is discharged in a high rate, the LiCl film is easily broken and voltage drop is prevented.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to improvements in non-aqueous solvent batteries.

[Technical background of the invention and its problems]

Nonaqueous solvent batteries that use lithium and sodium as negative electrode active materials have a high energy density, excellent storage characteristics, and a wide operating temperature range, and are often used as power sources for calculators, watches, memory devices, and Quazzo batteries. has been done. Such batteries are composed of a negative electrode, an electrolyte, and a positive electrode. Generally, lithium or sodium is used as the negative electrode, and lithium perchlorate or borax is used as the electrolyte in a nonaqueous solvent such as propylene carbonate, γ-butyrolactone, or dimethoxyethane. A solution prepared by dissolving an electrolyte such as lithium chloride is used as the positive electrode, and manganese dioxide, fluoride, and graphite are respectively used as the positive electrode.

Among the above-mentioned batteries, so-called lithium-thionyl chloride batteries, which use lithium in the negative electrode9 and thionyl chloride (SOcz2) as the main positive electrode active material, are attracting attention because of their particularly high energy density. Such a battery has a positive electrode made of a carbon and metal current collector, and uses 5OCt2 in which a Lewis acid and a Lewis base are dissolved as an electrolyte. Among the Lewis acids, aluminum chloride (A/!, C2
3), lithium chloride (LICt) as the Lewis base,
Lithium carbonate (L12C03) and the like are used. 9- 5OC1y serves as both a positive electrode active material and an electrolyte, but the film formed on the lithium negative electrode prevents direct contact between the positive and negative electrodes and maintains its function as a battery. .

By the way, in the lithium-thionyl chloride-based battery, since the positive electrode active material 5OCt2 is in direct contact with the negative electrode lithium, a LiCt film, which is a reaction product, is formed on the surface of the negative electrode lithium. This produced LiC4 film has the function of preventing direct contact between the negative electrode lithium and 5OCt2, and plays a role in preventing battery capacity deterioration during storage.
During discharge, it acts as a resistance component and causes a voltage drop at the beginning of discharge. The degree of this voltage drop is negligible when the discharge current is microampere-order, but it can be ignored when the discharge current is large, especially when stored at high temperatures for a long time and the growth of the LICt film is inhibited. When discharging occurs after a considerable discharge or at low temperatures, there is a drawback that a large voltage drop occurs at the start of discharging, and it takes a considerable amount of time to recover to a predetermined voltage.

On the other hand, a non-aqueous solvent battery (Japanese Unexamined Patent Publication No. 57-3372) has been proposed that includes an electrolytic solution using L12CO3 as a Lewis base. However, such a battery cannot effectively suppress the voltage drop in the early stage of discharge.

[Purpose of the invention]

The present invention aims to provide a nonaqueous solvent battery that does not cause a voltage drop even during the initial stage of large current discharge.

[Summary of the invention]

In the present invention, a negative electrode such as lithium and a positive electrode mainly composed of porous carbon are provided in a can with a separator interposed therebetween.
)' as the main positive electrode active material, aluminum chloride (HTC
In a battery containing an electrolytic solution containing t3) and lithium carbonate (L12CO3), by using an electrolytic solution in which the molar ratio of aluminum chloride and lithium carbonate is 0.5 or more of lithium carbonate to aluminum chloride,
Suppresses the growth of LiC4 film that forms on the lithium negative electrode,
When discharging a large current, the main purpose is to facilitate the destruction of the LiC2 film and prevent a significant voltage drop.

The above aluminum chloride (Atct3) and lithium carbonate (
The reason for limiting the molar ratio of L12C03) is that htct
, if Li3Co3 is less than 0.5, the effect of inhibiting the growth of the LiC2 film on the Li negative electrode cannot be sufficiently exerted. In addition, Li2Co5 for htct3
A molar ratio of 1.3 is sufficient.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to 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 pressure-bonded to the inner peripheral surface of the can 1.

Inside the can body 1 inside the negative electrode 2, the positive electrodes are housed via a separator 41r42 made of, for example, a nonwoven fabric made of glass fiber, which is disposed inside the can body 1 and near the bottom surface of the can body 1.

For example, to make this positive electrode, mix a commercially available polytetrafluoroethylene emulsion with 5-acetylene black at a ratio of 1 (hvt%), add water and ethyl alcohol, and stir at room temperature for about 2 hours. Forming into a sheet, pressing it onto a metal current collector 5 made of a stainless steel net, drying the sheet under vacuum at 150°C to form a band having a porous carbon layer 6, and winding this into a spiral shape. built by.

Further, in the can body 1 above the positive electrode, an insulating paper 7 supported by the separator 41 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. A hole 9 is opened in the center of this metal top 8. A positive electrode terminal 10 in the form of a knob is fixed in this hole 9 through a metal-glass sealing material 11 in an electrically insulated manner. The lower end of this positive electrode terminal 10 is connected to the metal current collector 5 of the positive electrode 3 with a lead wire 12.
connected via. And, inside the can body 1 is the above-mentioned) J? Electrolytic solution 13 injected from the tube-shaped positive electrode terminal 10 hole is accommodated. As this electrolyte 13, the following 6
- Three types of compositions A to C shown below were used. After the electrolyte 13 is injected, a seal 14 made of stainless steel, for example, is inserted into the /f tube-shaped positive electrode terminal 0, and the terminal 10 and the inserted seal 14 are laser welded. The hole of the positive electrode terminal 10 is then sealed.

Composition of electrolytic solution> Electrolytic solution A...AtCl3: 1.8 mol/l, L
i2Co3: 0.6 mol/lc molar ratio 3:1) was added to distilled 5OC62.

Electrolyte B...AtC63: 1.8 mol/l, L
i2Co3: O19 mol/l (molar ratio 2:1) was added to distilled 5OC62.

Electrolyte C...htct3: t, s mol/l, L
12Co3: 1.8 mol/l (molar ratio 1:1) was added to distilled 5OCt2. Therefore, each battery using the above three types of electrolytes was stored at 25°C for one week after assembly, and the 8Ω When discharge was performed with a constant resistance of , the characteristic diagram shown in FIG. 2 was obtained. In Fig. 2, A indicates the initial discharge curve of the battery using electrolyte A, B indicates the discharge curve of the battery using electrolyte B, and C indicates the discharge curve of the battery using electrolyte C. This is the same discharge curve. As is clear from this figure 2,
Compared to batteries using electrolyte A, batteries using electrolytes B and C have much smaller voltage drops, and htct3 and Li2CO
It can be seen that a battery using an electrolytic solution having a molar ratio of 10.5 or more to Li2Co3 to htct has excellent initial discharge characteristics.

In the above embodiments, a spirally wound strip of a metal current collector with a porous carbon layer crimped onto the metal current collector was used as the positive electrode, but the present invention is not limited thereto.

For example, a positive electrode made of a cylindrical porous carbon body with a metal current collector disposed on the outer or inner circumferential surface may be used.

〔Effect of the invention〕

As described in detail above, according to the present invention, a voltage drop can be significantly suppressed even in the initial stage of large current discharge, and a non-aqueous solvent battery with excellent initial discharge characteristics can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a non-aqueous solvent battery showing an embodiment of the present invention, and FIG. 2 is a diagram showing the discharge characteristics of the battery of this embodiment at the initial stage of large battery discharge. 1... Can body, 2... Negative electrode, l... Positive electrode, 4! ,
4□...Separator, 5...Metal current collector, 6...
Porous carbon layer, 8...Metal, 10... Pipe-shaped positive electrode terminal, 13... Electrolyte. Applicant's representative Patent attorney Takehiko Suzue 9- Continued from page 1 0 Inventor Yoshiyasu Aoki 3-4-10 Minamishinyo, Tokyo Parts Store Toshiba Battery Co., Ltd. 0 Applicant Toshiba Battery Co., Ltd. 322-3-4-10, Minamishinayo, Tokyo Parts Store

Claims (1)

[Claims] A negative electrode made of at least one of lithium, sodium, and aluminum and a positive electrode mainly composed of porous carbon are provided in the can with a separator interposed therebetween, and the positive electrode mainly contains sulfur oxyhalide in the can. A non-aqueous solvent battery containing an electrolyte as an active material, characterized in that the electrolyte contains aluminum chloride and lithium carbonate in a molar ratio of 0.5 or more of lithium carbonate to aluminum chloride. A non-aqueous solvent battery.