JPH04529Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to an explosion-proof sealing structure suitable for cylindrical lithium batteries and the like.

[Prior art] For example, Utility Model Application Publication No. 56-26863 and Utility Model Application Publication No. 61-
As described in Publication No. 87458, etc., the following explosion-proof sealing structure is known for lithium batteries and the like.

A composite lid is fitted to the inner periphery of the open end of a bottomed cylindrical metal battery case via an insulating sealing gasket, and the open end of the case is caulked inward to form a connection with the outer periphery of the composite lid. In the basic structure in which the sealing gasket is compressed between the two, a safety valve device for explosion-proofing is constructed in the part of the composite lid.

In other words, the above composite lid has a structure in which a diaphragm plate is sandwiched between a metal inner cover plate and a terminal plate, and the terminal plate and diaphragm plate are integrated by caulking the outer periphery of the inner cover plate. ing. There is a considerable space between the central portion of the terminal plate and the diaphragm plate, and a sharp cutting edge with a gas vent hole is provided in the center of the terminal plate, protruding toward the inner surface. A pressure hole (valve hole) is formed in the center of the inner cover plate, and this hole is closed with a diaphragm plate.

When the pressure inside the battery increases abnormally, the pressure acts on the diaphragm plate through the pressure guiding hole, causing it to expand upward. Then, the diaphragm plate comes into contact with the cutting blade and breaks. This allows the gas inside the battery to be safely released to the outside through the gas vent hole.

[Problems that the invention aims to solve] In the conventional structure described above, there is a hole (gas vent hole) created when the cutting edge is formed in the center of the terminal board, so it is difficult to insert the lead for external wiring here. There was a problem that it was difficult to weld the terminals. In the conventional structure, the outer peripheral portion of the terminal plate is in close contact with the diaphragm plate, and these three parts are integrated by caulking the inner cover plate. Therefore, it has not been possible to form a cutting edge with a gas vent hole near the outer periphery of the terminal plate.

This idea was devised in view of the above-mentioned conventional problems, and its purpose was to avoid creating a hole in the central convex part of the terminal board due to the formation of the cutting edge, and to create a seal with a highly reliable explosion-proof function. It's about providing structure.

<Means for Solving the Problems> Therefore, in this invention, in the basic structure in which the opening of the battery case is closed with a sealing gasket and a composite lid as described above, the composite lid is configured as follows.

(a) The above-mentioned composite lid has a structure in which a flexible diaphragm plate and an airtight sheet are overlapped and sandwiched on the outermost periphery of a metal inner lid plate, and this is further combined with a terminal plate.

(b) The diaphragm plate has a spacer in the center that is convex outward, and has an outer peripheral rib in the outer periphery that is convex outward, and the part between the spacer and the outer rib is It is a thin pressure sensitive part.

(c) The inner cover plate has a rising portion formed by bending the outer periphery upward, and a pressure guiding hole is formed in the flat plate portion.

(d) The rising portion of the inner cover plate is curled inward, and the outer circumferential rib of the diaphragm plate is hugged by the caulked portion.

(e) The terminal board has a central convex part whose central part becomes convex outward, and a cutting edge with a gas vent hole is provided on the outer circumferential side of the central convex part, protruding toward the inner surface. There is.

(f) The inner surface of the outer peripheral part of the terminal plate abuts the caulked rising part of the inner cover plate, and the tip of the cutting edge of the terminal plate faces the outer surface of the pressure sensitive part of the diaphragm plate. , a tip end portion of the spacer of the diaphragm plate faces an inner surface of the central convex portion of the terminal plate.

《Operation》 If the pressure inside the battery case becomes abnormally high,
The pressure acts on the diaphragm plate through the pressure guiding hole, causing the pressure sensing portion to swell outward. Then, the pressure sensitive part comes into contact with the cutting blade and breaks, and the internal gas is completely released from the gas vent hole.

<<Embodiment>> FIGS. 1 to 5 show the configuration of an embodiment of the present invention. In Fig. 1, 1 is a cylindrical metal battery case with a bottom, 2 is an insulating sealing gasket,
3 shows a composite lid which is the main part of the present invention.

An annular beading portion 1a is formed near the open end of the battery case 1, and a sealing gasket 2 is fitted into the inner periphery of the upper portion of the annular beading portion 1a.
A composite lid 3 is fitted into the inner periphery of the lid. The open end of the battery case 1 is caulked inward as shown by 1b, whereby the sealing gasket 2 is sandwiched between the battery case 1 and the composite lid 3 and compressed.

FIG. 5 shows the shape of the sealing gasket 2 as a single item. As shown in the figure, the gasket 2 includes a thick cylindrical portion 2a compressed between the case 1 and the composite lid 3;
It has a thin flat plate part 2b, and the flat plate part 2b has a central large pressure-conducting hole 2c, three small holes 2d,
A square internal wiring hole 2e and an internal wiring shot prevention piece 2f are formed.

The composite lid 3 includes a metal inner lid plate 40 and a terminal plate 50.
A flexible plastic diaphragm plate 60 is interposed between the two.

As shown in FIG. 4, the diaphragm plate 60
A cylindrical spacer 61 divided into four parts is protruded from the center of the upper surface, and a ring-shaped outer circumferential rib 62 is formed on the outer periphery of the upper surface. This spacer 61 and the outer peripheral rib 6
2 is a thin pressure sensitive part 63 that expands outward in response to high pressure. Note that a thin airtight sheet 64 is bonded to the lower surface side of the diaphragm plate 60. The airtight sheet 64 has a structure in which a thin metal plate is laminated with a plastic sheet.

As shown in FIG. 3, the inner cover plate 50 has a rising portion 51 formed by bending the outer periphery of a disk upward, and a large pressure-conducting hole 5 in the center of the disk.
2 is formed. As shown in FIG. 1, the diaphragm plate 60 is placed on the inner cover plate 50, and the rising portion 51 of the inner cover plate 50 is curled inward, and the diaphragm plate 60 is caused by the caulked portion. The outer circumferential rib 62 is hugged.

As shown in FIG. 2, the terminal board 40 has a central convex portion 41 that is convex outward at the center, and a round gas vent hole 42 in the flat plate portion on the outer peripheral side of the central convex portion 41.
Two cutting blades 44 each having triangular gas vent holes 43 are formed. The cutting blade 44 projects obliquely downward.

Further, as shown in FIG. 1, when the battery assembly is completed, the lower surface of the outer peripheral surface of the terminal plate 40 is in contact with the caulked rising portion 51 of the inner cover plate 50. Further, the tip of the cutting edge 44 of the terminal plate 40 faces the upper surface of the pressure sensing portion 63 of the diaphragm plate 60 with an appropriate distance therebetween. Further, the upper end of the spacer 61 at the center of the diaphragm plate 60 faces the lower surface of the central convex portion 41 of the terminal plate 40 with an appropriate distance therebetween.

Although not shown in the figure, a power generating element of a lithium battery is housed in the battery case 1, the negative electrode is connected to the battery case 1 by internal wiring, and the positive electrode is connected to the inner cover plate 50 by internal wiring. A lead piece for internal wiring on the positive electrode side is welded to the lower surface of the inner cover plate 50 at the internal wiring hole 2e of the sealing gasket 2. Inner cover plate 50
It is electrically connected to the terminal board 40 by a caulked rising portion 51. This connection may be spot welded.

In the above configuration, the internal pressure of the battery acts on the lower surface of the diaphragm plate 60 through the pressure guide hole 2c of the sealing gasket 2 and the pressure guide hole 52 of the inner cover plate 50, pushing it upward. When the diaphragm plate 60 is slightly displaced upward, the spacer 61 comes into contact with the lower surface of the terminal plate 40. When the pressure further increases, the pressure sensing portion 63 on the outer peripheral side of the spacer 61 deforms so as to bulge upward. Then, the upper surface of the pressure sensitive part 63 comes into contact with the cutting blade 44, and when this contact pressure increases to a certain extent, the pressure sensitive part 63 breaks around the point of contact with the cutting blade 44. As a result, the internal gas is discharged to the outside through the broken diaphragm plate 60 and the gas vent holes 42 and 43 of the terminal plate 40.

By the way, in the conventional structure, the central portion of the diaphragm plate serves as the pressure sensitive part, and it is easy to increase the amount of displacement (bulge amount) of the pressure sensitive part when receiving high pressure. In the present invention, since the outer circumferential portion of the diaphragm plate 60 is used as the pressure sensitive part 63, it can be said that the configuration is such that it is difficult to increase the amount of displacement (swelling amount) of the pressure sensitive part 63. Therefore, in the present invention, a spacer 61 is provided on the diaphragm plate 60 to restrict the deformation of the central portion of the diaphragm plate 60, and the deformation due to high pressure is caused by the pressure sensitive part 63.
We are trying to make sure that this occurs in a concentrated manner.

Further, an outer peripheral rib 62 is provided on the diaphragm plate 60, and this is configured to be directly embraced by the rising portion 51 of the inner cover plate 50, so that when the pressure sensitive portion 63 is about to bulge upward and deform, the diaphragm plate 60 This prevents the outer periphery from being pulled toward the center and moving. This is also effective in increasing the amount of swelling of the pressure sensing portion 63. If the outer circumferences of the diaphragm plate and the terminal plate are caulked together at the rising part of the inner cover plate as in the conventional structure, the fixing force of the outer circumferential rib 62 of the diaphragm plate 60 becomes very weak, and the outer circumferential rib 62 is easily pulled toward the center and moves.

<<Effects of the invention>> As explained in detail above, according to the explosion-proof sealing structure of the battery according to this invention, there is no gas vent hole associated with the formation of the cutting edge in the central convex part of the terminal board, and this part has no external Lead plates that require wiring can be welded without any problems. Also, by doing this, the explosion-proof valve structure is located on the outer circumferential side of the composite lid, but according to the configuration of the present invention, the reliability of the explosion-proof function is sufficiently high.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of an explosion-proof sealing structure according to an embodiment of the present invention, FIG. 2 is a plan view of a terminal plate in the same embodiment, and FIG. 3 is a plan view of an inner cover plate in the same embodiment. FIG. 4 is a plan view and a sectional view of a diaphragm plate in the same embodiment, and FIG. 5 is a plan view and a sectional view of a sealing gasket in the same embodiment. 1...Battery case, 2...Sealing gasket, 3
... Composite lid, 40 ... Terminal board, 41 ... Central convex part, 42 ... Gas vent hole, 43 ... Gas vent hole,
44... Cutting blade, 50... Inner cover plate, 51... Rising part, 52... Pressure conducting hole, 60... Diaphragm plate,
61...Spacer, 62...Outer circumferential rib, 63...
Pressure sensitive part, 64...airtight sheet.

Claims (1)

[Scope of Claim for Utility Model Registration] A composite lid is fitted to the inner circumference of the open end of a bottomed cylindrical metal battery case via an insulating sealing gasket, and the open end of the case is caulked inward. 1. An explosion-proof sealing structure for a battery, wherein the sealing gasket is compressed between the composite lid and the outer periphery of the composite lid, the composite lid having the following configurations (a) to (f). (a) The above-mentioned composite lid has a structure in which a flexible diaphragm plate and an airtight sheet are overlapped and sandwiched on the outermost periphery of a metal inner lid plate, and this is further combined with a terminal plate. (b) The diaphragm plate has a spacer in the center that is convex outward, and has an outer peripheral rib in the outer periphery that is convex outward, and the part between the spacer and the outer rib is It is a thin pressure sensitive part. (c) The inner cover plate has a rising portion formed by bending the outer periphery upward, and a pressure guiding hole is formed in the flat plate portion. (d) The rising portion of the inner cover plate is curled inward, and the outer circumferential rib of the diaphragm plate is hugged by the caulked portion. (e) The terminal board has a central convex part whose central part becomes convex outward, and a cutting edge with a gas vent hole is provided on the outer circumferential side of the central convex part, protruding toward the inner surface. There is. (f) The inner surface of the outer peripheral part of the terminal plate abuts the caulked rising part of the inner cover plate, and the tip of the cutting edge of the terminal plate faces the outer surface of the pressure sensitive part of the diaphragm plate. , a tip end of the spacer of the diaphragm plate faces an inner surface of the central convex portion of the terminal plate.