JPS63175345A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To case making a battery as well as to improve a contact between a positive electrode and battery case by forming a current collecting body with a memory alloy deformable as required. CONSTITUTION:A positive electrode current collecting body 8 interposed between a positive electrode 7 and battery case 3 is formed with a shape alloy deformable in a flat state at a low temperature and a spring state at a normal temperature in a flat shape organic electrolyte battery. Therefore a contact between a positive electrode and battery case is improved in a normal temperature operation, a current collecting body becomes a flat state in a low temperature assembling, and thereby a battery can be made easily and excellently.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in organic electrolyte batteries.

BACKGROUND OF THE INVENTION Since organic electrolyte batteries have a high energy density, thin and flat coin-shaped batteries are now required. In order to construct such a thin battery, it is necessary to fill the lower part of the battery case with the positive electrode all at once, as in a conventional button-shaped battery. Since the backing also requires a certain thickness, there is a limit to how thin the battery can be made. Therefore,
A configuration is adopted in which the backing is pushed into the periphery of the bottom of the battery case and the bottom of the battery case is used as a seat for the backing. In this case, since the positive electrode does not contact the side surfaces of the case, but only the bottom surface, it is necessary to ensure sufficient electrical contact between the positive electrode and the case, which also serves as its terminal.

Conventionally, there have been the following methods for electrically contacting the positive electrode and the case.

(1) Fill one side of the current collector with a mixture, peel off part of the mixture, and weld the current collector and case.

(2) An uneven portion is formed on the inner surface of the battery case by welding a current collector 8 such as a metal net in advance, and a positive electrode mixture is pressure-bonded onto the uneven portion (FIG. 4).

(3) As shown in FIG. 6, the current collector 8 has an upper end of its side peripheral wall surrounding the side surface of the molded positive electrode, and holds the molded positive electrode floating above the battery case, and is located below the battery case. The contacting inward bent portion has a curved surface or a cone-shaped inclined portion, and is pressurized by deforming spring elasticity (Japanese Patent Application No. 1982-
50936).

Problems to be Solved by the Invention In the method (1) above, the contact between the positive electrode and the case is complete;
Although the discharge characteristics are good, the manufacturing process is very complicated, resulting in high costs. In addition, the capacity decreases because part of the mixture is peeled off, and conversely, if the filling amount is increased by the amount removed, the electrode plates become thicker, which is disadvantageous for flat batteries. (Compared to (1), the manufacturing process is greatly simplified and is effective to some extent even for flat batteries, but it still requires a current collector welding process and requires a positive electrode mixture.) The crimpability of the method (3) is simple, and the crimpability is effective because it utilizes spring elasticity, but
Since the shape of the current collector has a curved surface or a cone-shaped slope from the beginning of manufacturing and assembly, the thickness of the components inside the battery is inevitably increased, and when the battery is sealed, the overall thickness, that is, the total height of the battery, is reduced. This causes unnecessary force to act inside the battery, causing problems such as unstable leakage resistance due to electrolyte splashing out due to increased internal pressure, and variations in the total height of the battery. These methods (1) to (3) all affect the discharge performance of the battery.

There are advantages and disadvantages in storage performance, leakage resistance, and manufacturing process.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a flat organic electrolyte battery that has good contact between the positive electrode and the battery case and is easy to manufacture.

゛Means for solving the problem In order to solve this problem, the present invention provides a current collector made of a shape memory alloy that is flat at low temperatures and deforms into a spring shape at room temperature between the inner bottom surface of the battery case and the positive electrode. It is something that involves the body.

Effect: According to this configuration, reliable contact between the positive electrode and the case can be obtained. In addition, when assembling the battery, since the current collector is flat, it is easy to load the mixture, and the smooth sealing prevents the electrolyte from spilling out during sealing, making the total height of the battery stable. Since it deforms into a spring-like shape, the positive electrode mixture can be better crimped, which helps improve battery performance.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of an organic electrolyte battery to which the present invention is applied. In the figure, 1 is a stainless steel sealing plate, 2 is a polypropylene insulating backing, 3 is a stainless steel battery case, and 4 is a sealing plate 1. A negative electrode sheet of lithium is crimped onto the uneven surface of the inner surface, 6 is a separator made of polypropylene nonwoven fabric, 6 is a thick impregnated material,
7 is a positive electrode mainly composed of manganese dioxide, to which acetylene black as a conductive material and styrene pumediene rubber as a binder are added and mixed and pressure-molded into a disk shape; 8 is a main element of the present invention having a spring shape; The positive electrode current collector is made of a shape memory alloy, and the electrolytic solution is a solution of lithium perchlorate in a mixed solvent of propylene carbonate and dimethoxyethane, which is impregnated into the impregnating material 6, separator S, and positive electrode 7. has been done. Here, the positive electrode current collector 8 is a titanium or nickel alloy that has a flat shape at low temperatures as shown in FIG. 2a, and deforms into a spring shape at room temperature as shown in FIG. A shape memory alloy manufactured by the company was used. That is, during battery assembly, the positive electrode current collector is kept at a low temperature and handled in a flat shape, and after battery assembly, it is returned to room temperature and deformed as shown in Figure 2 to improve the pressure bond between the positive electrode case and the positive electrode mixture. It is.

The metal net current collector shown in FIG. 4 of the conventional example is welded to a case, an uneven part is formed, and a positive electrode mixture is pressed onto the uneven part.The battery is made up of a metal net current collector shown in FIG. 6 of the conventional example. B9 The battery shown in FIG. 1, which is an embodiment of the present invention, is a battery in which the shown inwardly bent part has a cone-shaped inclined part and uses a deformable spring-like elastic positive electrode current collector. A battery with a diameter of 23 mm and a height of 2.6 Trr1 nm was fabricated. 100 each in the table below
internal resistance of prototype batteries, number of liquids spilling out during battery assembly,
This figure shows the distribution of battery height dimensions.

Effects of the Invention As is clear from the above explanation, by using a current collector made of a shape memory alloy that is flat at low temperatures and deforms into a spring shape at room temperature between the battery case and the positive electrode, the case and the positive electrode are This has the advantage that the internal resistance is small due to sufficient contact between the battery and the battery, the variation in the total height of the battery is small, the manufacturing process is stable and simple, and mass productivity can be improved.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of an organic electrolyte battery of the present invention, Figure 2 is a positive electrode current collector of the present invention, where a is a cross-sectional view showing the shape at low temperature, and b is a cross-sectional view showing the shape at room temperature. Fig. 3 a, b,
c is a sectional view of a positive electrode current collector of another example, and FIGS. 4 and 6 are longitudinal sectional views of a conventional organic electrolyte battery. 1... Sealing plate, 2... Insulating backing, 3... Battery case, 4... Negative electrode, 6
... Separator, 6 ... Impregnation material, 7.
...Positive electrode, 8...Positive electrode current collector. Name of agent: Patent attorney Toshio Nakao and 1 other person
salary

Claims (1)

[Claims] A negative electrode made of a light metal as an active material, a positive electrode, and an organic electrolyte are interposed between a battery case that also serves as a positive terminal, a sealing plate that also serves as a negative terminal, and the battery case and the sealing plate, with the bottom of the battery case serving as a seat. The battery is sealed with compressed insulating packing and has a current collector interposed between the inner bottom surface of the battery case and the positive electrode, wherein the current collector is flat at low temperatures and spring-like at room temperature. An organic electrolyte battery comprising a deformable shape memory alloy.