JPH10125304A - Sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed battery which has an superior safety device that operates during failures at elevated temperature and which uses a sealing element for which productivity is good to close the opening of a battery case. SOLUTION: A sealed battery comprises a lid plate 2 having a valve hole 3 in approximately the center; a valve plate 1 secured to approximately the center of the lid plate 2 to close the valve hole 3; a terminal board 7 having a gas vent 9 and located above the lid plate 2; an insulator 5 insulating the lid plate 2 from the terminal board 7; and a shape-memory-alloy plate 4 located above the periphery of the lid plate 2 and having one end sandwiched between the periphery of the lid plate 2 and the insulator 5 and the other end put into contact with the terminal board 7. The battery also includes a sealing element, such that the shape memory alloy plate 4 is deformed at a predetermined temperature and higher, so that the other end of the shape memory alloy plate 4 leaves the terminal board 7, the sealing element closing the opening of a battery case 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed battery in which the opening of a battery case is sealed with a sealing member having a safety device which operates when an abnormality occurs due to an increase in temperature, and more particularly to the sealing member.

[0002]

2. Description of the Related Art As a conventional sealing body having a safety device which operates when an abnormality occurs due to a rise in temperature, for example, Japanese Utility Model Laid-Open No.
There is one described in JP-A-6359. In the sealing body described in this publication, electrical connection between the lid plate and the terminal plate is made by contact via a PTC element (positive temperature coefficient element). The PTC element operates as a current suppressing element by increasing the resistance value of the element at the time of abnormality accompanied by a temperature rise. However, there is a problem that a PTC element that cannot completely cut off the current only by suppressing the current is unsafe.

On the other hand, in the sealing body described in Japanese Utility Model Application Laid-Open No. Sho 62-5564, the shape memory alloy is deformed at the time of an abnormality accompanied by a temperature rise, so that the current can be completely cut off. However, the electrical connection between the lid plate and the terminal plate is performed by welding one end of a spring-shaped shape memory alloy to the terminal plate and bringing the other end of the shape memory alloy into contact with the lid plate by the elastic force of the spring. Therefore, a welding process is indispensable for this sealing body. Therefore, this sealing body has a problem that the manufacturing process is complicated and the productivity is very poor because of the presence of the welding process.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a sealed battery having an excellent safety device which operates in the event of an abnormality accompanied by a rise in temperature, and which closes the opening of the battery case with a sealing body having good productivity. It is intended to provide.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a cover plate having a valve hole at a substantially central portion, a valve plate fixed to a substantially central portion of the cover plate so as to close the valve hole, and a gas vent hole. A terminal plate located above the lid plate, an insulator for insulating between the lid plate and the terminal plate, and an insulator located above the peripheral portion of the lid plate and having one end insulated from the peripheral portion of the lid plate. A sealing member which is sandwiched by the body and has the other end in contact with the terminal plate, and wherein the shape memory alloy plate is deformed at a predetermined temperature or more and the other end of the shape memory alloy plate is separated from the terminal plate. And the opening of the battery case is hermetically sealed with the sealing body.

The sealing member has a resin body sandwiched between a substantially central portion of the cover plate and the terminal plate, and the resin body has a guide hole communicating the valve hole and the gas vent hole. Preferably, the guide hole and the shape memory alloy plate are separated by a resin body.

[0007]

First, it will be mentioned that the battery sealing body of the present invention has an excellent safety device which operates in the event of an abnormality accompanied by a temperature rise.

[0008] The battery sealing body of the present invention has two types of safety devices, a current interrupt system and a valve system.

In the current interruption method, an electric connection between the lid plate and the terminal plate is held by an end of the shape memory alloy plate located above the peripheral portion of the lid plate between the peripheral portion of the lid plate and the insulator. And that the other end of the shape memory alloy plate is in contact with the terminal plate, and in the event of an abnormality involving a rise in temperature, the shape memory alloy plate deforms and separates from the terminal plate, The electrical connection between the lid plate and the terminal plate is interrupted. However, this current cut-off method does not cause a problem that the current cannot be cut off completely as in the case of using a PTC element.

[0010] On the other hand, the valve system means that the communication between the inside of the battery and the outside of the battery is closed, that is, the closing of the valve hole existing substantially at the center of the cover plate is performed by closing the valve plate so as to close the valve hole. When the temperature of the battery rises and the internal pressure of the battery exceeds a predetermined value, the valve hole is damaged due to breakage of the valve plate or peeling off from the lid plate. Being open,
The communication between the inside of the battery and the outside of the battery releases pressure inside the battery.

It is to be noted that the battery sealing body of the present invention is characterized in that the current interrupting method is constituted by an upper portion of the peripheral portion of the cover plate and the valve system is constituted by a substantially central portion of the cover plate. It is compatible with the system.

From the above, it can be said that the battery sealing body of the present invention has an excellent safety device that operates when an abnormality occurs due to an increase in temperature.

The sealing body of the battery of the present invention has a resin body sandwiched between a substantially central portion of the cover plate and the terminal plate, and the resin body has a guide hole communicating with the valve hole and the gas vent hole. Has,
The reason why the guide hole and the shape memory alloy plate are preferably separated by a resin body is as follows.

When the shape memory alloy plate deforms and separates from the terminal plate, a spark may be generated. Also, when the valve hole is opened, gas and electrolyte in the battery case are discharged from the valve hole into the sealing body. Therefore, when the discharged gas or electrolyte is flammable and the valve hole is opened and the flammable gas or electrolyte is present near the contact point of the terminal plate with the shape memory alloy plate, When a spark occurs, the battery may ignite. However, if there is a guide hole that communicates the valve hole and the gas vent hole and there is a resin body that separates the valve hole from the shape memory alloy plate, even if the valve hole is opened, the flammable gas or electrolytic Since the liquid is guided from the valve hole to the gas vent hole and does not exist near the contact point of the terminal plate with the shape memory alloy plate, there is no ignition of the battery due to the spark.

[0015] A valve plate may be provided between the resin body and the cover plate, and the resin body may function as follows.

When the valve plate is a hot-melt fixable thin film obtained by laminating a metal thin plate and a hot-melt fixable film, and the valve hole is closed by hot-melt fixing the hot-melt fixable film to the lid plate, the battery is closed. When stored at a high temperature, the hot-melt adhesive film melts and the adhesiveness of the valve plate to the cover plate decreases. Therefore, when the valve plate is a hot-melt adhesive thin film obtained by laminating a metal thin plate and a hot-melt adhesive film, the resin body sandwiched between the substantially central portion of the cover plate and the terminal plate is used as the valve plate. By configuring the fixing portion with the cover plate to be pressed against the cover plate, it is possible to prevent a decrease in the fixability of the valve plate to the cover plate due to storage of the battery at a high temperature.

Next, the fact that the battery sealing body of the present invention has good productivity will be described.

In the battery sealing body of the present invention, the electrical connection between the lid plate and the terminal plate is established by connecting one end of the shape memory alloy plate located above the peripheral portion of the lid plate to the peripheral portion of the lid plate and the insulator. This is achieved by being sandwiched and the other end of the shape memory alloy plate being in contact with the terminal plate. Thereby, the sealing body of the battery of the present invention can be manufactured by a method of stacking the lid plate to which the valve plate is fixed, the shape memory alloy plate, the insulator, and the terminal plate in this order. Therefore, in the battery sealing body of the present invention, since the welding process is present, the manufacturing process is complicated, and the above-described problem of extremely low productivity does not occur.

From the above, it can be said that the battery sealing body of the present invention has good productivity.

Even when the sealing body has a resin body sandwiched between the substantially central portion of the cover plate and the terminal plate, the addition of this resin body does not add a welding step. Since the resin body is incorporated in the terminal plate, and the lid plate to which the valve plate is fixed, the shape memory alloy plate, the insulator, and the terminal plate in which the resin body is incorporated are stacked in this order, the sealing body can be manufactured. It can be said that the battery sealing body of the present invention has good productivity.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sealed battery according to the present invention will be described below with reference to the drawings by using a cylindrical spiral battery. However, the embodiments described below embody the technical idea of the present invention and do not limit the present invention.

FIG. 1 is a schematic structural sectional view of the sealed battery according to the present invention, and FIG. 2 is an exploded schematic structural sectional view of the sealing body of FIG.

[Production of Sealing Body] A valve plate 1 which is a hot-melt adhesive thin film obtained by laminating a 20-μm-thick aluminum thin plate and a 40-μm-thick hot-melt adhesive polyethylene film is placed in a stainless steel lid plate 2. On the bottom surface, the valve hole 3 and the vicinity of the valve hole 3 are arranged so as to cover the same, and the hot-melt fixable polyethylene film is disposed in contact with the lid plate 2.
The valve plate 1 was hot-melt-fixed to the cover plate 2 by hot pressing at 40 ° C. × 10 seconds. Note that the entire surface of the valve plate 1 except for the portion facing the valve hole 3 is fixed to the lid plate 2. When the internal pressure of the battery becomes equal to or higher than a predetermined value, the valve hole 3 is opened due to breakage of the valve plate 1 or peeling from the cover plate 2, and the internal pressure of the battery is released.

Next, as shown in FIG.
A ring-shaped shape memory alloy plate 4, an insulator 5 made of polypropylene, and a terminal plate 7 made of stainless steel in which a resin body 6 is incorporated are stacked.

Then, as shown in FIG. 1, the peripheral portion of the cover plate 2 is caulked to the shape memory alloy plate 4, the insulator 5, and the terminal plate 7 which are memorized so as to be deformed at a predetermined temperature.
A sealing body was prepared.

The electrical connection between the cover plate 2 and the terminal plate 7 is made by contacting one end (outer side of the ring) of the shape memory alloy plate 4 with the peripheral portion of the cover plate 2 and the other end of the shape memory alloy plate 4. The end (the inner peripheral side of the ring) is in contact with the terminal plate 7. The insulator 5 electrically insulates one end of the lid plate 2 and one end of the shape memory alloy plate 4 from the terminal plate 7. Therefore, when the temperature of the sealed battery becomes equal to or higher than a predetermined value, the shape memory alloy plate 4 is deformed (the shape memory alloy plate 4 in FIGS. The electrical connection between the end and the terminal plate 7 is cut off.

The resin body 6 is sandwiched between a substantially central portion of the cover plate 2 and the terminal plate 7. And the resin body 6 is provided with the valve hole 3.
And a guide hole 10 communicating the gas hole 9 with the gas vent hole 9 to isolate the valve hole 3 from the shape memory alloy plate 4. Further, the resin body 6 presses the fixed portion of the valve plate 1 with the cover plate 2 against the cover plate 2. Therefore, as described in the section of the operation, the resin body 6
Prevents the ignition of the battery due to the spark when the shape memory alloy plate 4 is deformed and separates from the terminal plate 7 and the decrease in the adhesion of the valve plate 1 to the cover plate 2 when the battery is stored at a high temperature. I do.

[Preparation of Positive Electrode with Current Collector] A positive electrode having an appropriate viscosity is prepared by mixing manganese dioxide as an active material, graphite as a conductive material, a fluororesin as a binder, and water at a predetermined ratio. A mixture was prepared.

This positive electrode mixture was coated on an expanded metal made of stainless steel and rolled with a roller to produce a rolled positive electrode.

The rolled positive electrode plate was cut into a predetermined size and dried to prepare a positive electrode.

The expanded metal was exposed by removing a part of the mixture layer of the positive electrode.

A current collector plate 11 made of a stainless steel sheet was spot-welded to the exposed portion to produce a positive electrode 12 with a current collector plate.

[Preparation of negative electrode with current collector plate] A metal lithium plate was cut into a predetermined size to prepare a negative electrode.

A current collecting plate 13 made of a nickel thin plate was pressure-bonded to a part of the negative electrode to produce a negative electrode 14 with a current collecting plate.

[Preparation of Spiral Electrode Body] The positive electrode 12 with a current collector and the negative electrode 14 with a current collector are
5 to form a spiral electrode body.

[Preparation of Electrolyte Solution] Lithium perchlorate was dissolved in a solvent composed of propylene carbonate and 1,2-dimethoxyethane to prepare an electrolyte solution.

[Preparation of Sealed Battery] The spiral electrode body, the battery case opening side insulating plate 16 and the battery case bottom insulating plate 17 were inserted into the battery case 8.

Next, a fitting groove 18 is formed near the opening of the battery case 8, and the insulating gasket 1 is inserted into the fitting groove 18.
9 was assigned.

Then, the current collector plate 13 on the negative electrode side was spot-welded to the bottom of the battery case 8, and the current collector plate 11 on the positive electrode side was spot-welded to the cover plate 2 of the sealing body.

Then, the electrolytic solution was injected into the battery case 8, and the electrolytic solution was sufficiently permeated into the electrodes and the like.

Thereafter, the vicinity of the opening of the battery case 8 was caulked to the above-mentioned sealing body to produce a sealed battery.

[0042]

The battery sealing body of the present invention has two types of safety devices, a current interrupting type and a valve type, as safety devices that operate in the event of an abnormality accompanied by an increase in temperature. In the battery sealing body of the present invention, the current interrupting method is configured at an upper portion of a peripheral portion of the cover plate, and the valve method is configured at substantially the center of the cover plate, so that the current interrupting method and the valve method are performed. I have both.

Further, in the battery sealing body of the present invention, one end of the shape memory alloy plate located above the peripheral portion of the lid plate is electrically connected to the insulator of the lid plate and the terminal plate. And that the other end of the shape memory alloy plate is in contact with the terminal plate. Thereby, the sealing body of the battery of the present invention can be manufactured by a method of stacking the lid plate to which the valve plate is fixed, the shape memory alloy plate, the insulator, and the terminal plate in this order.

Therefore, by implementing the present invention, there is provided an excellent safety device which operates at the time of an abnormality accompanied by a temperature rise,
In addition, it is possible to provide a sealed battery in which the opening of the battery case is sealed with a sealing body having good productivity.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of the structure of a sealed battery according to the present invention.

FIG. 2 is an exploded schematic structural sectional view of the sealing body of FIG. 1;

[Explanation of symbols]

 1. Valve plate 2. Lid plate 3. Valve hole 4. Shape memory alloy plate 5. Insulator 6. Resin body 7. Terminal plate 8. Battery case 9. Gas vent hole 10.・ Guide hole

Claims (2)

[Claims] A cover plate having a valve hole at a substantially central portion thereof; a valve plate fixed to a substantially central portion of the cover plate so as to close the valve hole; A terminal plate located above, an insulator for insulating between the lid plate and the terminal plate, and an insulator positioned above a peripheral portion of the lid plate and having one end insulated from a peripheral portion of the lid plate. A shape memory alloy plate sandwiched by a body and having the other end in contact with the terminal plate. The shape memory alloy plate is deformed at a predetermined temperature or more, and the other end of the shape memory alloy plate is the terminal plate. A sealed battery comprising: a sealing member separated from the battery case, wherein the sealing member seals an opening of the battery case. 2. The sealing body has a resin body sandwiched between a substantially central portion of the lid plate and the terminal plate, and the resin body has a guide hole communicating the valve hole and the gas vent hole. 2. The sealed battery according to claim 1, wherein the guide hole and the shape memory alloy plate are separated by the resin body. 3.