JPS63195965A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To increase the safety and discharge performance by shrinking and bending in the winding core direction a separator extruding from an electrode body by heating the lower part of the electrode body to cover the lower edge of the electrode body. CONSTITUTION:A cathode 1, an anode 2, and a separator 3 interposed between them are spirally wound to form an electrode body. The separator extruded from the lower edge of the electrode body is heated to shrink and bend and to cover the lower part of the electrode body. Disadvantages such as the difficulty of inserting the electrode body into a case caused by an increase in the outer diameter of the electrode body due to the formation of the wrinkle of the separator and an increase in the dispersion of discharge performance caused by uneven penetration of electrolyte are prevented. The coming off of a positive mix is also prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a cathode plate made of metallic lithium, an anode plate,
This invention relates to a cylindrical lithium battery having a spiral electrode body with a separator interposed between the two electrode plates.

Conventional technology Conventionally, the following three methods have been used to construct the separator of this implantable body.
The cross-sectional views of each electrode body are shown in FIGS. 3 to 5.

The first method is to use manganese dioxide as the core material of expanded metal or net, as shown in Figure 3.

A strip separator 3 is interposed between an anode plate 1 made by filling and drying a mixture containing fluorinated graphite or the like as an active material, and a cathode plate 2 containing lithium metal as an active material, so that the entire structure is spirally formed. This is the way to do it.

The second method is to construct an anode plate 1 covered with a separator 3 and a cathode plate 2 in a spiral shape, as shown in FIG.

In the third method, as shown in FIG. 6, each of the anode and cathode 1 and 2 is covered with a separator 3 to form a spiral structure.

Problems to be Solved by the Invention In the conventional configuration, in the case of the first method, the separator 3
Since the upper and lower parts of the electrode body are open, there is a high risk that the anode mixture will fall off in the winding core part, which has a small curved diameter, and cause an internal short circuit, especially in the lower part of the electrode body.

Further, in the case of the second and third methods, wrinkles occur in the separator at the shaded area A in FIG. 6 when the separator is wound spirally. This increases the outer diameter of the polarized body, making it difficult to insert it into the case. Therefore, the electrode plate size must be made thinner or shorter to cope with the problem, resulting in a reduction in discharge capacity. Furthermore, since it is difficult for the electrolytic solution to penetrate uniformly into the wrinkled portions, there is also the problem that variations in discharge characteristics increase.

The present invention solves the above problems and aims to improve safety and discharge characteristics.

Means for Solving the Problems In order to solve these problems, the present invention provides a method of heating at least the lower part of both the upper and lower ends of the electrode body constructed by the first method to protrude from the electrode body. The lower end surface of the electrode plate constituting the electrode body is covered by shrinking and bending the separator in the direction of the winding core.

Function: This configuration solves the problems of internal short circuits caused by falling of the anode mixture and deterioration and variation in discharge characteristics.

Embodiment FIG. 1 is a sectional view of a cylindrical lithium battery according to an embodiment of the present invention, which will be described in detail below.

In FIG. 1, an anode plate 1 is made by applying an anode mixture containing manganese dioxide as a living substance to a core material made of an expanded net made of titanium or stainless steel, and then drying the mixture. 4 is an anode lead plate made of the same material as the core material and spot welded to the core material.

The cathode plate 2 is made of metal lithium, and a cathode current collector 5 is crimped to the negative side thereof.

The separator 3 is a nonwoven fabric made of polypropylene, polyethylene, or a mixture of polypropylene and polyethylene.
The microporous membrane sheet was cut into wide strips for the anode and cathode (1, 2). In this example, a microporous membrane sheet made of polypropylene was used.

Next, a separator is interposed between these anodes and cathodes 1 and 2, and the whole is spirally wound to form an electrode body.

and at least the lower end face of the electrode body, that is, the
, 2 (the heating temperature varies depending on the material of the separator, but in the case of this example it was heated to 14
(0 to 180"C), and then shrinking and bending to cover the lower part of the electrode body.Furthermore, in this example, the above operation was also carried out on the upper part of the electrode body, and as shown in Fig. 2, the lower part of the electrode body was covered. The upper and lower parts were covered with separators, thereby completing the structure of the spiral electrode body.

Next, the lower insulating plate 7 is attached to the electrode body and inserted into the case 8, the upper insulating plate 6 is attached, and a step is formed on the upper part of the case 8. lithium perchlorate was dissolved as a solute in a mixed solvent of dimethoxyethane and 1,2 dimethoxyethane). After attaching the sealing plate 9, the open end of the case 8 is caulked to complete the assembly of the battery.

Table 1 shows the number of internal short circuits between the inventive product and the conventional product, and 2
The average (n=1o), maximum, and minimum values of discharge capacity when performing 300Ω constant resistance discharge at 0'C are summarized. As is clear from these results, the present invention is extremely excellent in eliminating internal short circuits and stabilizing discharge characteristics.

Table 1 Effects of the Invention As described above, according to the present invention, the wrinkles of the separator that occur when a spiral electrode body is constructed by covering the electrode plate with a bag-like separator in advance as in the conventional case can be avoided. Difficult to insert into υ case with large outer diameter. In addition, there is no large variation in the discharge characteristics due to uneven penetration of the electrolyte, and since the upper and lower ends of the polarized body are covered by the heating and shrinkage of the separator, the anode mixture is difficult to fall off. Moreover, even if the mixture falls off, it can be prevented from spilling out.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a cylindrical lithium battery according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing the structure of a spiral electrode body according to an embodiment of the present invention, and FIGS. The figure is a vertical cross-sectional view showing the structure of a conventional spiral electrode body, and FIG. 6 is a diagram showing a wrinkled portion when a conventional separator-covering target plate is fully wound. 1... Positive and negative plates, 2... Cathode plates, 3...
... Separator, 4... Anode core material, 5...
... Anode lead plate, 6... Cathode current collector. Name of agent: Patent attorney Toshio Nakao and 1 other person f-
Omote Hakama Hayashi 2 - Sanugoku yoko ゛ - ° Biba Shi Ichi Tough --- P 舒 1 8 ~ 1 - 9... - C 组

Claims (1)

[Claims] An electrode body is formed by winding an anode plate and a cathode plate in a spiral shape with a band-shaped separator having a width wider than the two electrode plates interposed therebetween. An organic electrolyte battery characterized in that at least the lower end face is bent in the direction of the winding core to cover the end face of the anode and cathode plates.