JPS5875763A - Organic solvent battery - Google Patents

Abstract

PURPOSE:To improve the electrolyte-holding ability of a separator, and prevent increase of the internal resistance and interruption of the electric-discharge reaction by using as the separator, a nonwoven fabric consisting of a glass fiber and a complex fiber which is prepared by coating part of polypropylene fiber with polyethylene. CONSTITUTION:In a positive can 1 made of a stainless steel or a metallic plate, a positive mixture 2 principally consisting of a positive active material such as manganese dioxide or carbon fluoride is installed. A negative terminal 3 is attached to the positive can 1, with a gasket 4 interposed between them. A negative active material 5 made of lithium metal is pressed and fixed upon the inner wall of the terminal 3. A separator 6 made of a nonwoven fabric, which consists of a glass fiber with a diameter of 0.1-1.0mum and a complex fiber prepared by coating part of polypropylene fiber with polyethylene, is situated between the positive mixture 2 and the negative active material 5. An organic solvent electrolyte which is prepared by dissolving lithium perchlorate, lithium borofluoride or the like into propylene carbonate, 1,2-dimethoxyethane or the like is poured into such a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in separators for organic solvent batteries using light metals as negative electrode active materials.

General C:, Light Metal Specific I: In order to avoid the reaction between metallic lithium and water, organic solvent batteries using metallic lithium as the negative electrode active material must be However, the discharge reaction in organic solvent batteries is a reaction in which lithium ions move to the positive electrode side and produce reaction products within the positive electrode mixture. As the reaction progresses, the positive electrode mixture swells.

The polypropylene nonwoven fabric described above does not have good liquid retention properties, so in conventional batteries, as the positive electrode mixture swells, the electrolyte in the mixture is absorbed, and the electrolyte in the separator The disadvantages of this method are that the battery gradually decreases and eventually becomes depleted, the internal resistance of the battery increases, the discharge pressure decreases, and the discharge reaction is interrupted because the liquid communication is cut off.

Therefore, there was a need for a separator with strong liquid retention properties that would prevent electrolyte from migrating to the positive electrode mixture side.

According to Hibiki, a non-woven fabric is made by intertwining glass fibers with a Fi fiber diameter of 0.1 to 1.0 μm and composite fibers in which a part of the surface of polypropylene fibers is covered with polyethylene, using a nine separator. The purpose is to obtain an organic solvent battery with low internal resistance without interruption of the discharge reaction.

Glass fiber Fi used in the battery separator of the present invention,
The fiber diameter is 0.1 to 1.0 μm and the electrolyte retention capacity is high. However, the strength of glass fiber alone is weak and unsuitable, and although the strength can be obtained by intertwining C niboripropylene fibers and heat-sealing them, in addition, a part of the surface of the polypropylene fibers is covered with polyethylene. When the composite fibers and glass fibers are intertwined and heat-sealed, the strength is sufficient.

Polypropylene fiber and glass lI1. The electrolyte retention capacity is greater than that in combination with a battery, and the discharge characteristics of the battery are improved.

Table 1: -j constant results of electrolyte holding power of each separator. Separator (a) Fi This invention product has a fiber diameter of 0.
．． Composite *M in which the surfaces of glass fibers and polypropylene fibers of 1 to 1.0 μm are coated with polyethylene at a coverage rate of 50%.
The separator (b) is composed of a nonwoven fabric with a fiber diameter of 0.1 to 1.0. The separator (a) is a nonwoven fabric made of am glass fiber and polypropylene fiber, and the separator (a) is a nonwoven fabric made of polypropylene alone.

Table 1 The electrolyte retention strength shown in Table 1 was measured as follows:
Immerse each separator in electrolyte solution for 30 minutes and take it out.
Glass plate tilted at an angle of 45°
It was calculated as (10017k).

As shown in Table 1, the separator of the present invention has superior electrolyte retention ability compared to the conventional separator.

Next, an embodiment of the m-solvent battery of the present invention will be described with reference to FIG.

1 is a positive electrode can made of a metal plate such as stainless steel.

The positive electrode can 1 houses a positive electrode mixture 2 mainly composed of positive electrode active materials such as manganese dioxide and carbon fluoride. 3F
The negative electrode terminal plate 3 is fitted to the positive electrode can II through the backing 4, and a negative electrode active material 5 made of metallic lithium is crimped onto the inner surface of the negative electrode terminal plate 3. The interface between the positive electrode mixture 2 and the negative electrode active material 5 is made of a nonwoven fabric made of glass fibers with a fiber diameter of 0.1 to 1.0 μm and composite fibers in which a portion of the surface of polypropylene fibers is coated with polyethylene. A separator 6 is arranged. The battery is made up of an organic solvent electrolyte in which lithium perchlorate, lithium borofluoride, etc. are dissolved in propylene carbonate, 1,2-dimethoxyethane, etc.

Figure 2 shows that a mixture of 90% by weight of manganese dioxide, 9% by weight of phosphorous graphite, and 1% by weight of polytetrafluoroethylene was used as a positive electrode mixture with a diameter of 201° and a thickness of 0.51°.
A metal lithium disk with a diameter of 18" and a thickness of 0.25" was used as the negative electrode active material.
As an electrolyte, a mixture of propylene carbonate and 1,2-dimethoxyethane with a volume ratio of 1:1 was used, in which lithium perchlorate was dissolved at a ratio of 1 mol/l. Coverage rate of 0.1 to 1.0 μm glass fiber and polypropylene fiber surface with polyethylene: 50-
The discharge curve of the example battery (A) of this @mei using a nonwoven fabric composed of composite fibers coated with conjugate fibers is shown. The discharge is 500
It was carried out at a constant current of μA, and the horizontal axis shows the utilization rate with respect to the theoretical discharge capacity I of the positive electrode mixture.

@2 In the figure, (A) is an example of the present invention, but (0) is a comparative example using a conventional non-woven polypropylene fabric,
(B) is a comparative example using a nonwoven fabric separator made of glass fibers and polypropylene fibers with a fiber diameter of 0.1 to 1.0 μm. B) + (o
) It can be seen that the discharge utilization rate is significantly better than that of 0.0 or more.As described above, the present invention uses a fiber diameter of 0.1-1.
By using a nonwoven fabric made of 0 μm glass fiber and a composite fiber made of polypropylene fibers partially coated with polyethylene as a separator, the separator's electrolyte retention ability is good, and the positive electrode mixture expands due to discharge. This also prevents the electrolyte in the separator from decreasing or depleting, increasing internal resistance and discharging the reaction.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the organic solvent battery of the present invention, and FIG.
The figure is a comparison diagram of the discharge curve with a conventional battery.0 2...Positive electrode mixture 5...Negative electrode active material 6...
separator

Claims (1)

[Claims] (1) In an organic solvent battery 12 that uses a light metal as a negative electrode active material, a nonwoven fabric made of glass fiber and a composite fiber in which a portion of the surface of polypropylene fiber is coated with polyethylene is used as a separator, and the positive electrode mixture and Between negative electrode active material
2 intervening organic solvent cells 0