JPH0259589B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a non-aqueous solvent battery, and particularly to a non-aqueous solvent battery with an improved electrolyte that also serves as a positive electrode active material. [Technical background of the invention and its problems] Nonaqueous solvent batteries that use light metals such as lithium, sodium, and aluminum as negative electrode active materials have the characteristics of high energy density, excellent storage characteristics, and a wide operating temperature range. Because of this, they are often used as backup batteries for calculators, watches, and memory. Among these, batteries that use 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 high energy density. These cells have positive electrodes consisting of carbon and metal current collectors, typically aluminum chloride (AlCl ₃ ), aluminum bromide (AlBr ₃ )
A liquid oxyhalide of sulfur is used as an electrolyte, which is a solution of a Lewis acid such as lithium chloride or a Lewis base such as lithium chloride or lithium bromide. Therefore, the liquid oxyhalide serves both as a positive electrode active material and as an electrolyte, and by using a positive electrode with an appropriate shape, a battery with excellent high rate discharge characteristics can be expected. By the way, since the sulfur oxyhalide, which is the positive electrode active material of the battery described above, is in direct contact with the lithium of the negative electrode, a LiCl film, which is a reaction product, is generated on the surface of the negative electrode lithium. This LiCl film has the function of preventing direct contact between the negative electrode lithium and the oxyhalide, and 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. The degree of this voltage drop is negligible when the discharge current is minute on the μA order, but it cannot be ignored when the discharge current is large, and especially when stored at high temperatures for a long time, considerable growth of the LiCl film occurs. After discharging or at low temperatures, there is a problem in that a significant voltage drop occurs at the start of discharge, and it takes a considerable amount of time to recover to a predetermined voltage. [Object of the Invention] The present invention aims to provide a non-aqueous solvent battery that exhibits a small voltage drop even in the early stages of large current discharge. [Summary of the invention] The present invention provides a negative electrode made of a light metal such as lithium,
In a nonaqueous solvent battery composed of a positive electrode mainly composed of carbon and an electrolytic solution that also serves as a positive electrode active material and mainly composed of a sulfur oxyhalide, a solution containing the oxyhalide as the electrolytic solution is used. The main idea is to use one to which methacrolein is added. By using such an electrolytic solution containing methacrolein, a nonaqueous solvent battery with excellent initial discharge characteristics that does not show a significant voltage drop even when discharged at a large current after storage and has a short voltage recovery time can be obtained. can be obtained. The above methacrolein may be either a monomer or a polymer. Such methacrolein is 1 to 25 c.c. for monomers and 0.2 c.c. for polymers per 1 solution containing sulfur oxyhalides.
It is desirable to add in the range of ~10g. The reason for this is that if the amount of methacrolein added is less than the above lower limit value, the addition effect will be insufficient, whereas if it exceeds the upper limit value, no increase in effect will be observed, or the discharge capacity of the battery will decrease. . [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. Example 1 Reference numeral 1 in the figure denotes a stainless steel can which also serves as a negative electrode terminal with an open top surface, and a cylindrical negative electrode 2 made of metallic lithium is crimped onto the inner surface of this can. Inside the can 1 inside the negative electrode 2, a positive electrode 5 having a structure in which a cylindrical porous carbon layer 4 is crimped onto the outside of a metal current collector 3 made of a cylindrical stainless steel mesh is housed in a cage made of glass fiber nonwoven fabric. shaped separators 6 ₁ , 6 ₂
It is provided through. The positive electrode 5 is made by mixing, for example, commercially available acetylene black and polytetrachloroethylene, and molding this mixture into a cylindrical shape together with a metal current collector 3 made of a stainless steel mesh so that the current collector 3 is on the inside. After that, the porous carbon layer 4 is produced by drying the kneaded product under vacuum at 150°C. Further, in the can body 1 above the positive electrode 5 , an insulating paper 7 having a hole in the center and supported by the separator ₆₁ 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 the metal top 8, and a pipe-shaped positive electrode terminal 10 is fixed to the metal top 8 in an electrically insulated manner through a metal-glass sealing material 11. ing. The positive electrode terminal 10 has a lead wire 1 at its lower end.
2 to the metal current collector 3 of the positive electrode 5 . The can body 1 accommodates an electrolytic solution 13 injected from the pipe-shaped positive electrode terminal 10. This electrolytic solution 13 is a solution in which aluminum chloride (AlCl ₃ ) and lithium chloride (LiCl) are dissolved in thionyl chloride (SOCl ₂ ) at a concentration of 1.5 moles, and methacrolein (monomer liquid) is added at a concentration of 2 c.c.
It was added. Further, a needle body 14 made of stainless steel, for example, is inserted into the pipe-shaped positive electrode terminal 10, and the hole of the positive electrode terminal 10 is sealed by laser welding the tip of the terminal 10 and the inserted needle body 14. Comparative example 1 1.5 each of AlCl ₃ and LiCl in SOCl ₂ as electrolyte
A battery having the same structure as in Example 1 was assembled except that a battery without the addition of mol/dissolved methacrolein was used. Therefore, the batteries of Example 1 and Comparative Example 1 were stored at 25°C for 3 months after assembly.
When a constant resistance discharge of 30Ω was performed and the characteristics at the initial stage of discharge were investigated, the characteristic diagram shown in FIG. 2 was obtained. In addition,
In FIG. 2, A shows the discharge curve of the battery of Example 1, and B shows the discharge curve of the battery of Comparative Example. As is clear from Figure 2, methacrolein (monomer liquid)
It can be seen that the battery of Example 1, which uses an electrolytic solution to which . Example 2 2 g of polymethacrolein produced by polymerizing in dimethylformamide using azobisisobutyronitrile as a polymerization initiator was added at 1.2 mol/1.
A battery having the same structure as in Example 1 was assembled except that an electrolytic solution added to an AlCl ₃ /LiCl-based thionyl chloride solution was used. Comparative example 2 1.2 each of AlCl ₃ and LiCl in SOCl ₂ as electrolyte
A battery having the same structure as in Example 1 was assembled except that a battery containing no added mole/dissolved polymethacrolein was used. Therefore, the batteries of Example 2 and Comparative Example 2 were stored at 45°C for 20 days after assembly, and 30Ω
A constant resistance discharge was conducted to examine the minimum voltage at the start of discharge and the time it took for the voltage to recover to 2.5V. The results are shown in the table below.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide a non-aqueous solvent battery with excellent initial discharge characteristics, such as suppressing voltage drop and shortening voltage recovery time even in the initial stage of large current discharge.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a nonaqueous solvent battery showing an example of the present invention, and FIG. 2 is a diagram showing the discharge characteristics at the initial stage of large current discharge in the battery of Example 1 and the battery of Comparative Example 1. . 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 terminal, 13... Electrolyte.

Claims (1)

[Claims] 1. In a nonaqueous solvent battery composed of a negative electrode made of light metals such as lithium, sodium, and aluminum, a positive electrode mainly composed of carbon, and an electrolyte that also serves as a positive electrode active material and mainly composed of sulfur oxyhalide. . A non-aqueous solvent battery, characterized in that the electrolyte is a solution containing the oxyhalide to which methacrolein is added.