JPS60225349A - Nonaqueous electrolyte cell - Google Patents

Abstract

PURPOSE:To improve the long-time shelf life of a nonaqueous electrolyte cell by coating at least the portion kept in contact with a gasket among surfaces of a positive electrode can and a negative electrode can containing positive electrode and negative electrode active materials with a Teflon film. CONSTITUTION:A negative electrode 3 made of a light metal such as lithium, sodium, aluminum, a positive electrode 6 made of manganese dioxide, carbon fluoride, iron sulfide, etc., and a separator 7 impregnated with a nonaqueous electrolyte are laminated and stored between a positive electrode can 4 and a negative electrode can 1, which are sealed with a gasket 8 to form a nonaqueous electrolyte cell. In this case, at least the portion kept in contact with the gasket 8 among surfaces of the positive electrode and negative electrode cans 4, 1 is coated with a water-repellant Teflon film. Accordingly, the infiltration of water from outside can be prevented even if the gasket 8 has some slacks after a long time, thus the long-time shelf life can be improved.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a non-hydroelectronic battery using a light metal as the negative electrode active material.
This invention relates to improving the long-term storage stability of liquid batteries.

<Prior Art> In recent years, so-called non-aqueous electrolyte batteries that use a light metal such as lithium for the negative electrode and a non-aqueous organic electrolyte for the 1m solution have attracted attention. The reason for this is that their high energy density and long-term storage stability are much superior to batteries using conventional aqueous electrolytes.

In these non-aqueous electrolyte batteries, since the active material hardly dissolves in the electrolyte, it was thought that the cause of the deterioration of the electrical properties after storage for a period of time was moisture entering from outside the battery. In reality, the long-term shelf life of conventional non-aqueous electrolyte batteries of this type is said to be approximately 5 years, and after that time, moisture from the outside enters through the battery seal and reacts with active materials such as lithium. It has been confirmed that this causes deterioration. Recently, this type of battery has been required to have a long shelf life of 10 years or more for use as a backup power source for watches and computer memories, and there has been a strong demand for improved sealing properties of the battery.

<Objective of the Invention> The present invention aims to provide a non-aqueous electrolyte battery that enables long-term storage performance of 10 years or more.

<Structure of the Invention> The present invention improves the sealing performance by sealing the positive electrode and electrode can, in which the positive electrode and negative electrode active materials are collected, by coating the can surface that comes into contact with the gasket with a Teflon film. Same as above.

In accordance with the present invention (to explain with a specific example), in a battery having a cross-sectional structure as shown in FIG.
As shown in the enlarged view of the sealing part in the figure, the can surface is coated with a Teflon film, which further improves the sealing performance.

Conventionally, 18 chromium and 8 chromium were used as positive electrode and electrode can materials.
Polypropylene has generally been used as a gasket material for stainless steel mesh, such as Nickel.

However, if the structure shown in FIG. 1 is used as is, no matter how strongly the gasket is compressed to improve its adhesion to the can, it will not be possible to achieve long-term storage of more than five years. The reason for this is thought to be that after a long period of time, stress relaxation or "loosening" of the gasket occurred, and eventually moisture in the outside air entered through the gap between the can and the gasket. The present invention eliminates these conventional drawbacks,
By coating the surfaces of the positive electrode and the sealed portion of the electrode can with water-repellent Teflon, even if the gasket relaxes stress, it extremely effectively prevents moisture from entering through the gap between the can and the gasket. . L-shi will be explained in detail below using a real sister example.

<Sister Example of the Invention> Sister Example An electrode can 1 was produced by drawing from an SO8,504 stainless steel plate (0.25 m thick), and four positive electrode cans were produced from an 817S450 stainless steel plate (0.25 m thick) by drawing. The electrode can 1 is equipped with a stainless steel mesh (8υ5516,
50 mesh) was spot welded and lithium foil (126 mesh) was spot welded.
m thickness) tl'16mK was punched and crimped onto the stainless steel mesh. Next, a separator 7 made of a polypropylene nonwoven fabric is placed on it, and propylene carbon futons, l-1,
Inject 1 mole of lithium perchlorate dissolved in an equal ratio mixture of 2 dimethoxyethane into an electrolyte tube and peel. The positive electrode active material is
Mix 185 parts of Mn0, black@10s, and 5 parts of Teflon powder, weigh 550119, and put it in a stainless steel mesh (8υ551
6.50 mesh). In this case, MnO* is commercially available MnO! , was heated to 400°C for 4 hours.

After 6 ft of this compressed positive electrode active material was placed on the separator, the positive electrode can 4 was finally assembled via a gasket 8 made of polypropylene.

The end of the positive electrode can was sufficiently bent inward by caulking to form a battery. It should be noted that these packings were not so-called trenches, but had been sufficiently water-removed in advance by distillation or drying, and all assembly was done in an argon atmosphere. Also, the battery size in this case is 20w
k, and the total height was 1.6M.

A comparative study was conducted on various sealing part configurations as described below, using basically the same composition and manufacturing method.

(1) The gasket contact surface of the positive electrode and electrode can,
It was baked with Teflon and coated with a gold film of about 58 μm thick.

(2) Teflon spray was applied to the gasket surface to provide a 5 μm Teflon coating.

(3) A gasket was fabricated by cutting using Teflon resin (polytetrafluoroethylene resin).

In addition to these five types of sealing part configurations, 50 batteries each were manufactured by adding the conventional example, and a long-term storage test was conducted.

As an accelerated test for long-term storage evaluation, the voltage at 500 Ω load was measured at -10°C after being left at 60°C and 90° relative humidity for 108 days (equivalent to 5 years) and 200 days (equivalent to 10 years). was measured.

The results are shown in Table 1. Each value is the average value of n=50.

Table 1 As shown in the results in Table 1, compared to conventional batteries, the storage stability is improved in the case of (υ, +21, (3)) in which Teflon is used in the sealing part. I understand.

Among them, the case (1) in which the surfaces of the positive electrode and negative 1 wax can are coated with a thick Teflon film (ri) has extremely good storage stability and
child. The reason for this is that the gasket has been relaxed by 16 points.
l on the sealing part! t + winding with a gap, moisture in the outside air is the gold N in the can
Table 11IIt: It is believed that IJt+ had entered the battery, and it is thought that the water repellency of C9 and Teflon was effective in coating the metal surface of the can [flk with Teflon film]. It will be done. In addition, 60℃, 90% IRH
It was confirmed in an experiment in '411 that 200 days at room temperature is equivalent to about 10 years at room temperature.

<Effects of the invention> As detailed above, by utilizing the water repellency of Teflon,
It has been found that the Teflon coating on the surfaces of the positive and negative electrode cans can more effectively prevent moisture from entering through the metal surface than simply interposing Teflon in the sealing part.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a battery according to the present invention, an actual sister example, and No. 21 is an enlarged view of the main part of the seal in FIG. 1. 1... Negative electrode can 2... Stainless steel mesh - 5... Lithium foil 4... Positive electrode can 5°/° stainless steel mesh 6...
- Positive electrode active material 7... Separator 8... Gasket 9.10... Teflon coating layer

Claims (1)

[Claims] Light metals such as lithium, sodium, and aluminum are used as negative electrode active materials, manganese dioxide, and carbon fluoride. In a non-aqueous electrolyte battery consisting of a positive electrode active material such as iron sulfide and a non-aqueous electrolyte, at least the portion of the surface of the positive electrode and negative electrode cans that contain the positive electrode and negative electrode active materials that come into contact with the gasket is coated with a Teflon film. A non-aqueous electrolyte battery characterized by being coated with.