JPH03134952A - Package type cell - Google Patents

Abstract

PURPOSE:To release generated gas to the outside smoothly by furnishing an exterior resin case with a gas exhaust hole conjugate with the safety valve device of a cell, and arranging a heat resistant foamed substance between the safety valve device and gas exhaust hole. CONSTITUTION:A resin case 2 accommodates an element cell 1 so that its pin-shaped terminals 1A, 1B are exposed. The case 2 is provided with a gas exhaust hole 2a conjugate with the safety device of the element cell 1, and heat resistant foamed substance 3 is arranged between the safety valve device and exhaust hole 2a. This permits the gas in the cell to pass easily through the foamed substance 3 even though the heat emitted from the cell actuates the safety device of cell, and the gas sputters out from the exhaust hole 2a provided in the package, which prevents rupture and/or explosion of the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an explosion-proof construction of a packaged battery that is optimal for supplying power to a circuit board.

BACKGROUND OF THE INVENTION In recent years, electronics such as ICs and LSIs have made remarkable progress, and demand for primary and secondary batteries as power sources for electronic precision equipment that utilizes these devices is rapidly increasing. In addition, with the diversification of devices, these types of batteries are becoming increasingly diverse, and not only are they used singly, but batteries in which multiple batteries are electrically connected in series or in parallel are becoming increasingly necessary. There is. Lithium batteries, which use alkali metals such as lithium as negative electrode active materials and metal oxides, halides, graphite fluoride, etc. as positive electrode active materials, are being used as high energy density batteries. be. Because this type of battery has a high energy density, safety designs such as a safety valve are usually installed in the battery to ensure safety in the event of heat generation due to an abnormal condition such as a short circuit. be.

Problems to be Solved by the Invention As described above, a tsuku-sokage type battery, which is designed for safety by installing a safety valve on the battery and is molded inside a package, may be in an abnormal state such as a short circuit, excessive charging, or discharging, and the battery may be damaged inside the package. When the battery's safety valve was activated, the lack of a gas exhaust hole caused internal pressure to build up inside the package, which in extreme cases could cause the package to burst and damage the equipment used.

Means for Solving the Problems The present invention provides a packaged battery that solves the above-mentioned problems. Specifically, a gas exhaust hole connected to the battery's safety valve device is provided in the exterior resin case, a heat-resistant foam is placed between the battery's safety valve device and the gas exhaust hole, and the surrounding area is molded and fixed with resin. This constitutes a packaged battery.

Function: According to the packaged battery of the present invention, when the battery generates heat due to an abnormality caused by external or internal factors, the internal pressure of the battery increases and the safety valve is activated, the generated gas can be smoothly released to the outside. It is.

Embodiment FIG. 1 shows a packaged battery according to the present invention, 1 is a unit cell, and pin-shaped positive terminal IA and negative terminal I are attached to the positive and negative terminal surfaces of the unit cell by resistance welding, laser welding, etc.
B is fixed by welding. 2 is a resin case housing the unit cell so as to expose the exposed portion of the pin-shaped terminal of the unit cell, and the material thereof is a thermoplastic resin such as ABS resin, polypropylene resin, or polycarbonate resin. . The resin case 2 is provided with a gas exhaust hole 2a connected to a safety valve device of the unit cell, and a heat-resistant foam 3 is disposed between the safety valve device and the gas exhaust hole.

The heat-resistant foam 3 is a foam made of a corrosion-resistant metal such as nickel, SUS, or copper, a silicone resin, an epoxy resin, or a urea resin foam, and has a foaming degree of 50% or more. 4 is a molding resin material that fills the space of the resin case, and is a normal urethane resin.

These include Epoquine resin, UV-curable acrylic resin, etc.

Reference numeral 5 denotes a lid that closes the opening of the resin case 2, and is made of the same material as the case material, and the two are ultrasonically welded and integrated as shown in Figure 2 to form a packaged battery. It consists of

FIG. 3 is a sectional view of essential parts showing an example of a safety valve device for a unit cell. A is a valve body that expands upward as the internal pressure of the battery rises, and a plate plate B with a valve hole B1 in the center, The bent portion B2 of the dish plate is bent inward by a terminal plate C having a cutting blade C1 and a gas vent hole C2 at the top, and the valve body A is fixed thereto by caulking. Therefore, when an abnormality occurs in the battery and the internal pressure of the battery increases, the valve body bulges upward, and the valve body A is destroyed by the cutting blade C1 provided on the terminal board C, releasing the gas inside the battery to the outside.

Next, regarding the effectiveness of the present invention, a manganese dioxide lithium battery with a diameter of 17.5 mm, a height of 33.5 mm, and a capacitance of 1300 mAh was constructed, and a package type battery with a width of 50 mm, a height of 27 mm, and a depth of 25 mm was constructed.
A short circuit was caused in an atmosphere at a temperature of 60° C., and the number of bursts of the packaged batteries at that time was compared. The results are shown in Table 1. Invention product 1 in the table is a nickel foam with a foaming degree of 60%, invention product 2 is a silicone resin foam with a foaming degree of 55%, and invention product 3 is a foam with a foaming degree of 70%. 5US
434, and a normal urethane resin was used as the molding resin. As a comparative example, a package type battery was constructed by molding a normal urethane resin without using a foam as in the present invention.

The number of tests was 200 for each type.As is clear from Table 1, in the product of the present invention in which a foam with a foaming degree of 50% or more is provided in the safety valve device part of the battery, the battery is either external or internal. If the battery's safety device is activated due to heat generation (in the case of the test product, the battery surface temperature rose to approximately 130'C), the gas inside the battery will easily pass through the foam made of heat-resistant material. The waste can be scattered outside through the waste exhaust hole provided in the package, and the waste can be released outside the package before the internal pressure inside the package reaches a dangerous state, thereby preventing the battery from bursting or exploding.

In addition, if the degree of foaming is 50% or less, please refer to 43% or more for details.
At 49%, it takes a little time to exhaust the scum, so the sound when exhausting the scum becomes louder, but it is still effective. However, if it was less than 43%, some rupture occurred, which was an unfavorable experimental result.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a packaged battery according to the present invention;
FIG. 2 is a schematic cross-sectional view of the packaged battery taken along the X-Y line in FIG. 1, and FIG. 3 is a cross-sectional view of a main part of the battery safety valve device. 1...Battery, LA, IB...Terminal,
2...Resin case, 2a...Exhaust hole, A...Valve body, B...Dish plate, C...
...Terminal board, 3...Foamed resin, 4...
・Mold resin, 5...Resin lid, B1...
・・Valve hole, B2・・Bending part, C1・・・・
...Cutting blade, C2...Gas vent hole.

Claims (3)

[Claims] (1) In addition to providing a safety valve device with a gas vent hole on the surface of the unit cell terminal, batteries equipped with pin terminals of various shapes are housed in an exterior resin case so that the exposed terminal part of the pin terminal is exposed. The battery is a packaged battery in which the inner space of the outer resin case is molded with resin, and a foam is disposed in a portion that abuts the gas exhaust hole of the safety valve device of the unit cell, and the foam is in the outer resin case. A packaged battery connected to a gas vent hole. (2) The packaged battery according to claim 1, wherein the foam is a heat-resistant metal or resin. (3) The packaged battery according to claim 1, wherein the foam has an expansion rate of 50% or more.