JPH0334049Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a safety valve device for a battery, and in particular, the present invention relates to a safety valve device for a battery, and in particular, an outer can that also serves as a unipolar terminal housing a power generation element and a terminal member of the other polarity are connected via an insulator. The present invention relates to a simple safety valve device suitable for a battery having a metal sealing lid that is airtightly fixed, and a joint between the outer can and the sealing lid is welded by, for example, laser welding.

(B) Prior art In the battery of the above structure, compared to a battery structure in which an insulating packing is interposed between the outer can and the sealing lid, such as a conventional nickel-cadmium battery, the battery is Since almost the entire body is made of metal, it has the advantage of increasing capacity and achieving high sealing.

When a safety valve device is attached to a battery having such a high sealing property, a safety valve device that does not impair the high sealing property and has a simple structure is required.

Therefore, a structure may be considered in which a gas vent hole is formed in the metal sealing lid, the gas vent hole is closed with a thin metal plate, and the peripheral end of the metal thin plate is welded to the sealing lid (see FIG. 1). This is because when the internal pressure of the battery rises abnormally, the metal thin plate is pressed by the gas generated inside and the welded part between the metal thin plate and the sealing lid is severed, and during this time the gas escapes and prevents damage to the battery. Because the extraction hole is blocked with a thin metal plate,
There is no loss of airtightness.

FIG. 1 is a cross-sectional view of a battery equipped with the safety valve device described above, and FIG. 2 is an enlarged cross-sectional view of a main part for explaining the operation of the safety valve device in FIG.

In FIGS. 1 and 2, reference numeral 1 denotes an exterior can that also serves as a positive terminal, in which a power generating element 2 is housed. 3 is attached to the opening of the outer can 1, and the joint part is welded 10, for example by laser welding.
The negative electrode terminal member 5 is airtightly fixed to the central through hole of the metal sealing lid with an insulating member 4 interposed therebetween. Reference numeral 6 denotes a metal ring that is fitted onto the head of the negative electrode terminal member 5 and is tightened and fixed by a pressing portion that presses the head.

The sealing lid 3 is further provided with a gas vent hole 31.
The gas vent hole 31 is closed with a thin metal plate 7 made of stainless steel, for example, and the peripheral edge of the thin metal plate 7 is welded to the sealing lid 3.
It is set to 0.

In such a structure, the operation of the safety valve device is normally in the state shown in Fig. 2A, but if the gas pressure inside the battery rises abnormally due to abnormal heat generation due to an internal short circuit, for example, the state shown in Fig. 2B occurs. The thin metal plate 7 is bent upward by the gas pressure (arrow), and when the pressure reaches a predetermined pressure or higher, the welded part 20 is cut as shown in Figure 2C, and the gas inside the battery is released into the atmosphere through the gap. It is.

(c) Problems to be solved by the invention The battery (comparative battery) equipped with the safety valve device having the structure shown in FIGS. , it is excellent in terms of airtightness. however,
When a thin metal plate is constructed from a simple flat plate,
The operation of the safety valve device is observed when the gas pressure becomes considerably high, but sufficient operation cannot be obtained when the gas pressure is low, and there is a problem in terms of the operational response of the safety valve device.

Note that it is possible to reduce the adhesive strength of the peripheral edge of the thin metal plate so that the safety piece device operates even at low gas pressure, but in this case, it is not preferable because it reduces the sealing performance of the battery. I can't say that.

Therefore, the present invention has been made in view of these points, and it is an object of the present invention to provide a battery having a safety valve device with high sealing performance and excellent operational responsiveness.

(d) Means for Solving the Problems A battery equipped with the safety valve device of the present invention includes an outer case that also serves as a unipolar terminal, a metal sealing lid, a terminal member of the other polarity, an insulator, a thin metal plate, and a power generation element. The unipolar terminal-doubling exterior can has an opening at one end, the metal sealing lid has a gas vent hole, and the insulator has a gas vent hole in the metal sealing lid. and other polarity terminal members,
The thin metal plate consists of a peripheral portion and a central portion,
The metal sealing lid is welded to one end of the unipolar terminal-cum-exterior can and closes the opening, and the other polarity terminal member is airtightly attached to the metal sealing lid via the insulator. the thin metal plate covers and closes the gas vent hole;
The central portion of the thin metal plate protrudes toward the inside of the unipolar terminal-cum-casing can through the gas vent hole, and the peripheral end portion of the thin metal plate is welded and bonded to the metal sealing lid. It consists of the
The power generation element is housed in a space constituted by the unipolar terminal-cum-contact outer can and the metal sealing lid, and when the internal pressure of the battery increases, the center portion of the metal thin plate is connected to the unipolar terminal. It is characterized in that the outer can that also serves as a terminal protrudes outward and is inverted, so that the adhesive portion is cut and the gas is released outside the space.

(E) Effect With the structure of the present invention, the central part of the thin metal plate protrudes toward the inside of the outer case that also serves as a unipolar terminal through the gas vent hole, so that when the internal pressure of the battery rises, the central part of the thin metal plate The stress caused by the metal thin plate becomes larger than that in the case where the metal thin plate is made of a flat plate. The stress caused by this gas is then applied to the center of the thin metal plate to increase the internal volume of the battery.
This central portion has good operational response, protrudes toward the outside of the unipolar terminal-cum-casing can, and is reversed.

As a result, a large peeling force is applied to the bonded area at the peripheral edge of the thin metal plate, which acts as a fulcrum.
It will be disconnected from here. In this way, gas is released to the outside of the battery, and rupture of the outer can etc. can be prevented.

(f) Example The present invention will be illustrated below, but it has the same features as the comparative battery described in the prior art section above.
The explanation will be omitted.

The battery of the present invention basically has the structure shown in FIG. The difference from the battery shown in FIG. 1 lies in the structure of the thin metal plate. The structure of the thin metal plate 7' used in the battery of the present invention is shown in FIG. 3A as a cross-sectional view of the main part thereof. In this way, the thin metal plate 7'
The central portion of the metal sealing lid 3 protrudes toward the inside of the outer can 1 that also serves as a unipolar terminal through a gas vent hole 31 formed in the metal sealing lid 3 . Further, the peripheral edge of the thin metal plate 7' is
A bonding portion 20 is configured by being welded to the metal sealing lid 3.

When the gas pressure within the battery (indicated by the arrow) increases from the state shown in FIG. 3A, the gas within the battery presses against the thin metal plate 7', particularly at its center.

Then, when the gas pressure exceeds a certain value, the central part of the thin metal plate 7' is
protruding toward the outside of the unipolar terminal dual-purpose outer can 1;
Invert. Furthermore, it is deformed to the state shown in FIG. 3B, and the vicinity of the peripheral edge of the thin metal plate 7' is
It stands up at a certain angle. Therefore, the bonded portion 20 acts as a fulcrum, and a large peeling force is applied thereto. As a result, compared to the structure shown in FIG. 2, as shown in FIG. The metal sheet 7' is cut. As described above, the battery of the present invention has excellent operational response of its safety valve device.

(g) Effects of the invention As detailed above, the battery of the invention equipped with a safety valve device consists of an outer can that also serves as a unipolar terminal, a metal sealing lid, a terminal member of the other polarity, an insulator, and a thin metal plate. , a battery comprising a power generating element, wherein the unipolar terminal-cum-functional exterior can has an opening at one end, and the metal sealing lid has a gas vent hole,
The insulator insulates the metal sealing lid and the other polarity terminal member, the metal thin plate includes a peripheral end portion and a central portion, and the metal sealing lid insulates the metal sealing lid from the unipolar terminal terminal member. The other polarity terminal member is welded to one end of the can and closes the opening, the other polarity terminal member is hermetically fixed to the metal sealing lid via the insulator, and the metal thin plate is The gas vent hole is covered and closed, the central portion of the thin metal plate projects toward the inside of the unipolar terminal-cum-casing can through the gas vent hole, and the peripheral end portion of the thin metal plate is The power generation element is welded to the metal sealing lid to form an adhesive part, and the power generating element is housed in a space constituted by the unipolar terminal-cum-exterior can and the metal sealing lid, and the battery internal pressure is When raised, the central portion of the thin metal plate protrudes toward the outside of the unipolar terminal-cum-casing can and is reversed, cutting the adhesive portion and releasing gas to the outside of the space. Therefore, without impairing the high airtightness characteristic of this type of battery, it is possible to prevent battery destruction by ensuring that the gas inside the battery is released into the atmosphere with good operational response in the event of an abnormality. Yes, and its practical value is extremely large.

The present invention can be applied to various battery systems, including non-aqueous electrolyte batteries, alkaline primary batteries, and secondary batteries.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a battery equipped with a safety valve device of a comparative example, Figs. 2 A, B, and C are diagrams explaining the operation of the safety valve device of the same battery, and Fig. 3 A, B, and C are diagrams of a battery according to the present invention. It is a figure explaining operation of a safety valve device. 1... Exterior can, 2... Power generation element, 3... Metal sealing lid,
31... Gas vent hole, 5... Negative electrode terminal member, 6... Metal ring, 7, 7'... Metal thin plate, 10, 20... Adhesive part.

Claims (1)

[Scope of claim for utility model registration] An exterior can 1 that also serves as a unipolar terminal, a metal sealing lid 3,
Other polarity terminal member 5, insulator 4, and thin metal plate 7'
and a power generation element 2, the unipolar terminal-cum-exterior case 1 has an opening at one end, the metal sealing lid 3 has a gas vent hole 31, and the The insulator 4 insulates the metal sealing lid 3 and the other polarity terminal member 5, the metal thin plate 7' consists of a peripheral part and a central part, and the metal sealing lid 3 insulates the other polarity terminal member 5. It is welded to one end of the outer can 1 that also serves as a polar terminal, and closes the opening, and the other polar terminal member 5 is hermetically fixed to the metal sealing lid 3 via the insulator 4. The thin metal plate 7' covers and closes the gas vent hole 31, and the central portion of the thin metal plate 7' extends toward the inside of the unipolar terminal-cum-casing can 1 through the gas vent hole 31. The peripheral edge of the metal thin plate 7' is welded to the metal sealing lid 3 to form an adhesive part 20, and the power generation element 2 is connected to the unipolar terminal-cum-exterior can 1. The thin metal plate 7' is housed in a space formed by the metal sealing lid 3, and when the internal pressure of the battery increases, the central portion of the thin metal plate 7' protrudes toward the outside of the unipolar terminal outer can 1. . A battery characterized in that the adhesive portion 20 is cut when the battery is inverted, and the gas is released out of the space.