JPS62128454A - Nonaqueous solvent cell - Google Patents

Abstract

PURPOSE:To shorten voltage recovering time and improve discharge characteristics, by adding a vinyl polymer having the chlorine substituent of 57-70wt% into electrolytic solution. CONSTITUTION:A vinyl polymer having the chlorine substituent of 57-70wt% is added into electrolytic solution. The vinyl polymer having the chlorine substitu ent is the simple substance, the copolymer, or the mixture of a construction represented by the attached chemical formula. The content of these vinyl polymers in the electrolyte is kept in the range of 0.2-10g/l. In a concrete form, the cylindrical negative electrode 2 of metal lithium is fixedly pressed to the inner surface of a can 1, and the positive electrode 5 of a construction in which a cylindrical porous carbon layer 4 is fixedly pressed to the outside of the metal current collecting body 3 of the cylindrical mesh body made of stainless steel is provided into the can 1 inside the negative electrode 2, with being intervened by the separators 61, 62 of glass nonwoven fabric. Thus, voltage recovering time on the early time of great current discharge is shortened, further discharge voltage and discharge capacity are improved and so on, a nonaqueous solvent cell which is excellent in discharge characteristics can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Practical Field of the Invention] The present invention relates to a non-aqueous solvent battery, and more particularly to a non-aqueous solvent battery having an improved electrolyte that also serves as a positive electrode active material.

[Technical background of the invention and its problems]

Non-aqueous solvent batteries that use at least 1 of light metals such as lithium, sodium, aluminum, potassium, and calcium as negative electrode active materials have the features of high energy density, excellent storage characteristics, and a wide operating temperature range. From, one calculator watch.

It is often used as a backup power source for memory. 1
Among them, lithium was used for the negative electrode, and thionyl chloride (SOcz) and sulfuryl chloride (80° CI) were used as the positive electrode active material.
! Batteries using sulfur oxyhalides such as t) are attracting attention because of their particularly high energy density.

These cells have positive electrodes consisting of carbon and metal current collectors, typically Lewis acids such as aluminum chloride (AICJm), aluminum bromide (AIBra), and lithium chloride.
A liquid oxyhalide of sulfur in which a Lewis base such as lithium bromide is dissolved is used as the electrolyte. 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, in the above-mentioned battery, since the sulfur oxyhalide which is the positive electrode active material 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 L rcl 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 on the order of Pa orders, but it cannot be ignored when the discharge current is large, especially when stored at high temperatures for long periods of time. After considerable film growth has occurred or during discharge at low temperatures, a solar voltage drop occurs as soon as discharge begins.
It takes a considerable amount of time to recover to the specified voltage.
There was a problem called the so-called voltage delay phenomenon. The degree of this voltage delay phenomenon varies greatly depending on the temperature and time during battery storage, the current during discharge, etc., but it is considered that there is a practical problem if the voltage recovery time takes 15 seconds or more.

For this reason, several proposals have been made to solve the above problems, such as Japanese Patent Application Laid-Open No. 56-7360.
The publication discloses dissolving a vinyl polymer such as a homopolymer of vinyl chloride, vinylidene chloride, or a copolymer of vinyl chloride and vinyl acetate in an electrolytic solution. Although the voltage retardation phenomenon is certainly improved by dissolving vinyl polymers with chlorine substituents in the electrolyte, as a result of our research, we found that the degree of voltage recovery is lower than that of vinyl polymers with chlorine substituents. It has been found that the amount of chlorine substituents in the polymer is highly dependent on the amount of chlorine substituents in the polymer.

[Purpose of the invention]

The present invention aims to provide a non-aqueous solvent battery that has a small voltage drop even in the early stages of large current discharge, a short voltage recovery time, and excellent discharge characteristics.

[Summary of the invention]

The present invention relates to a non-aqueous solvent battery comprising a negative electrode made of a light metal such as lithium, a positive electrode mainly made of carbon, and an electrolyte that also serves as a positive electrode active material and made mainly of sulfur oxyhalide. , is characterized in that a vinyl polymer having 57 to 70% by weight of chlorine substituents is added to the electrolytic solution. In this way, a battery using an electrolyte containing a vinyl polymer having 57 to 70% by weight of chlorine substituents does not show a significant voltage drop at the start of discharge even when discharged at a large current after storage. recovery time is also short.

In this case, the degree of shortening of the voltage recovery time is much better than when a vinyl polymer having the same chlorine substituent group is added, but the amount of the chlorine substituent group is outside the above range. Furthermore, in addition to the above-mentioned effects, the battery of the present invention has features such as excellent discharge characteristics at low temperatures and little capacity deterioration due to long-term storage.

The vinyl polymer having a chlorine substituent in the present invention is
Refers to single polymers, copolymers, and mixtures of polymers having the structure represented by the following general formula.

The content of these vinyl polymers in the electrolyte is in the range of 0.2 to 9/l, particularly 0.2 to 9/l.
It is desirable to keep it within the range of . This is because if the content of the copolymer is less than 0.211/1, the effect of suppressing voltage drop etc. cannot be sufficiently exerted, and on the other hand, the amount is less than 0.211/1. ! i
This is because if it exceeds I/l, not only will the effect hardly increase, but the discharge capacity of the battery may even decrease.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 to 6 FIG. 1 is a sectional view showing the structure of a non-aqueous solvent battery in this example and a comparative example.

1 in the figure is a bottomed cylindrical can made of stainless steel, for example, with an open top that also serves as a negative electrode terminal.

A cylindrical negative electrode 2 made of metallic lithium is pressure-bonded to the inner surface of the can 1. 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 mounted. 6.

6! provided through. The positive electrode 5 is made by, for example, mixing commercially available acetylene black and polytetrafluoroethylene, and molding this mixture together with a stainless steel mesh metal current collector 3 into a cylindrical shape so that the current collector is on the inside. After that, it is dried under vacuum at 150° C. to form the porous carbon layer 4 from the mixed wire.

Further, in the can body 1 above the positive electrode 5, an insulating paper 7 having a central hole supported by the separator 6 is disposed. A metal top 8 is provided at the top opening of the can body 1.
is sealed by laser welding or the like, and a pipe-shaped positive electrode terminal 10 is electrically insulated and fixed to the metal top 8 through a glass sealing material 11 in the hole 9 at the center of the metal top 8. has been done. The lower end of the positive electrode terminal 10 is connected to the metal current collector 3 of the positive electrode 5 via a lead wire 12. The can body 1 accommodates an electrolytic solution 13 injected from the pipe-shaped positive electrode terminal 10.

Furthermore, an enclosure 14 made of, for example, a stainless steel ring is inserted into the pipe-shaped positive terminal 10, and the positive terminal 1
0 is sealed. .

As Examples 1 to 6, aluminum chlorides (AICIs) and lithium chloride (L
57.5, 58.6, 60, 64.5, 6, respectively, in an electrolytic solution containing 1.5 mol/l of iCA')
Six types of batteries were fabricated using electrolytes to which vinyl polymers (2y/Il) having chlorine substituents of weight coefficients of 7.5 and 69.5 were added.

Comparative Example 1゜5OCI, AlCl! and L iCA! each/F 1
-, 40 mol/l dissolved in electrolyte solution
1[: A battery having the same structure as in Example was assembled except that an electrolyte containing a vinyl polymer (a type of chlorinated polyethylene) having 1% of chlorine substituents was used.

Comparative Example 2 A vinyl polymer (polyvinyl chloride) with chlorine and ft substituents of 56.7 to 1 was added to an electrolytic solution in which 1.5 mol/l each of AlCls and LiCl were dissolved in 5OCIt.
A battery having the same structure as the example was assembled except that an electrolyte containing .

Comparative Example 3゜5OCI, Medium 1CAlCl, LiC1T each/z
The structure was the same as that of the example except that an electrolytic solution in which a vinyl polymer (polyvinylidene chloride) having 73.1% by weight of chlorine substituents was added to an electrolytic solution containing 1.5 mol/1 atom was used. Assembled the battery. After assembling, the batteries of Examples 1 to 6 and Comparative Examples 1 to 3 were stored at 60°C for 40 days, and then discharged at a constant resistance of 30Ω, resulting in a voltage of 2.5
The time taken to return to v, the average operating voltage, and the discharge capacity were measured.

The results are shown in FIG. 2 and Table 1.

As is clear from Figure 2 and Table 1, 57~
The battery containing a vinyl polymer with chlorine substituents of 70% and 41% has a shorter voltage recovery time of less than 15 seconds at the start of discharge compared to the battery containing a vinyl polymer with a chlorine content outside the above range. , and the discharge capacity is also large. Furthermore, it was confirmed that the battery according to the present invention has excellent discharge characteristics at low temperatures and less capacity deterioration due to long-term storage compared to the battery of the comparative example.

〔Effect of the invention〕

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

[Brief explanation of drawings]

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

Claims (1)

[Claims] Consisting of a negative electrode made of at least one of the light metals lithium, sodium, aluminum, potassium, and calcium, a positive electrode mainly made of carbon, and an electrolyte that also serves as a positive electrode active material and made mainly of sulfur oxyhalide. In the non-aqueous solvent battery, 57 to 70
A non-aqueous solvent battery characterized by adding a vinyl polymer having chlorine substituents in the amount of % by weight.