JPH0714559U - Square sealed battery - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a prismatic sealed battery which is equipped with a safety valve device having excellent pressure responsiveness and excellent in liquid leakage resistance even at high temperatures. [Constitution] A hollow rivet (3) of another polarity terminal is attached to a through hole provided in a part of the metal sealing lid (2) through an insulating member. The membrane valve body (4) is installed on the seat of the hollow rivet. The terminal cap (5) is installed on the top of the membranous valve,
Hollow rivet, membrane valve and terminal cap flange
(6) is crimped and fixed by crimping by the valve body clamping plate (7).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rectangular sealed battery as a power source for driving a portable device, and more particularly to an explosion-proof and safety structure against a rise in battery internal pressure and a rise in battery temperature at the time of short circuit, overcharge, overdischarge, etc. is there.

[0002]

[Prior art and its problems]

 In recent years, large currents and large outputs are required for batteries as power sources, such as laptop computers, portable information devices such as word processors, camera-integrated VTRs, AV devices such as LCD TVs, mobile communication devices such as mobile phones, etc. There is a wide variety of developing devices and there is a demand for batteries with higher energy density.

Since the cylindrical type, which is widely used as a sealed battery at present, has a circular portion in its cross section, when it is mounted on a device, there is a lot of waste in the storage portion in terms of volume. From the viewpoint of effectively utilizing a small space, it is preferable to use a prismatic sealed battery.

On the other hand, in the case of the prismatic sealed battery, a method of welding a metal lid plate to the opening of a metal bottomed rectangular tube containing a power generating element by using laser light has a point of productivity and reliability. It has been confirmed as the best result in the past.

However, in the prismatic sealed battery, the structure of the positive electrode terminal and the safety valve still has problems in downsizing, productivity, and reliability. That is, in a conventional cylindrical closed battery, as shown in FIG. 3, it is mounted by caulking a sealing body 28 also serving as another polar terminal at the opening of a cylindrical outer can 21 which also serves as one polar terminal having a built-in power generation element. The structure of attachment is common. In the figure, 22 is an insulating packing, 23 is a membrane valve, 24 is a sealing plate, 25 is an exhaust hole, 26 is a terminal cap, and 27 is a gas vent hole. However, in a square sealed battery, the case opening is square and the shape of the insulating member is also rectangular, so it is technically difficult to crimp, and even if it is crimped, a circular insulating member Since it is difficult to crimp with a uniform force as described above, there is a drawback that the liquid leakage resistance is poor. Also, this technical difficulty increases as the rectangular battery case becomes thinner.

[0006] Therefore, as an example of what is used for a prismatic sealed battery, as shown in Fig. 4, a hermetic structure using an insulating member 33 such as a glass seal or a ceramic seal is adopted, and an outer can also serving as a unipolar terminal. In some cases, 31 and the metal sealing lid 32 are welded together by laser welding or the like, and the other polarity terminal pin 34 is fixed through the insulating member 33.

However, in such a battery, due to its high airtightness, if the battery internal pressure rises due to misuse or abnormal environment, the outer can may abnormally swell and the battery may burst. In addition, in order to prevent the battery from bursting and to have a structure in which the insulating member 33 is destroyed when the internal pressure of the battery rises, the adhesion between the insulating member 33 and the metal sealing lid 32 or the insulating member 33 and the terminal pin 34 should be improved. It must be weakened, which will cause electrolyte leakage.

As described in Japanese Utility Model Publication No. 4-4359, the battery structure shown in FIG. 5 is a main part of the structure of a square sealed battery in which a rubber valve body is used as a safety valve. The metal sealing lid 42 is sandwiched from above and below by the insulating packing 44 and the insulating packing 45, the hollow rivet 43 is inserted into the through hole 49 of the insulating packing, and the washer 46 for current collection is inserted into the through hole 49 of the insulating packing, and the whole is lengthwise. Apply pressure to and expand and crimp the leg tips of the hollow rivet.

Next, the rubber valve body 50 is placed on the seat of the hollow rivet, and the terminal cap 47 and the seat of the hollow rivet 43 are spot-welded from above while pressurizing with the terminal cap 47 having the gas vent hole 48. The lid 40 is obtained as described above. 41 is an outer can.

Although this structure can be equipped with a safety valve having particularly good pressure responsiveness, a gap is apt to be formed between the rubber valve body and the seat of the hollow rivet, so that moisture in the outside air enters the battery and the battery is activated. There is a problem with the resistance to liquid leakage, which promotes the deterioration of substances and electrolytes and causes the electrolyte to leak from the gaps.

In view of the above problems, FIG. 6 attaches a film-shaped valve body made of a laminate of a heat-fusible resin film and a thin metal plate to the seat of the hollow rivet by heat-sealing, and closes the through hole of the hollow rivet. This is intended to improve the liquid leakage resistance. In the figure, 51 is an outer can, 52 is a metal sealing lid, 53 is a hollow rivet, 54 is an insulating packing, 55 is an insulating packing, 56 is a current collecting washer, 57 is a terminal cap, 58 is a gas vent hole, 59 Is a through hole, 60 is a membranous valve element, 61 is a cutting edge, and 62 is a through hole.

This heat-fusible resin film is made of, for example, a polypropylene-based resin in which 6 wt% of maleic anhydride is graft-polymerized to polypropylenelen to give a metal-fusible property. With this method, a safety valve with good pressure responsiveness can be obtained, but when exposed to high temperature, the heat-fusible resin film fused to the seat of the hollow rivet softens, and there is a problem that liquid leakage occurs. .

[0013] Therefore, it is an object of the present invention to provide a prismatic sealed battery with a safety valve device having a good pressure responsiveness and, at the same time, a battery excellent in liquid leakage resistance even at a high temperature.

[0014]

[Means for Solving the Problems]

 The present invention is provided with an outer can that also contains a power generation element and also serves as a unipolar terminal, a metal sealing lid that is electrically conductively fixed to the outer can and closes the opening of the outer can, and a part of the metal sealing lid. In a battery in which a hollow rivet is attached to the through hole via an insulating member, a membranous valve body is installed on the seat of the hollow rivet, and the membranous valve body is fastened by a valve body clamping plate to secure the hollow rivet. The problem described above is solved by closing the through hole of the rivet.

[0015]

[Action]

 According to the battery of the present invention, when the internal pressure of the battery rises due to overcharging, overdischarging, etc., the membrane-shaped valve element breaks and opens, releasing the internal pressure of the battery to the outside and preventing the battery from exploding. Furthermore, since the membrane valve body is fastened to the seat of the hollow rivet by the valve clamp plate, there is no liquid leakage due to softening of the heat-fusible resin film even at high temperatures, and it has excellent liquid leakage resistance. .

[0016]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of a sealed battery according to an embodiment. In FIG. 1, reference numeral 1 denotes an outer can that also serves as a negative electrode terminal and has a power generating element (not shown) built therein. Reference numeral 2 denotes a metal sealing lid that is conductively fixed to the opening of the outer can 1, and the joint between the two is welded by laser welding. The outer can 1 and the metal lid 2 are made of nickel-plated iron having a thickness of 0.4 mm. Reference numeral 3 is a hollow rivet made of aluminum, 4 is a membrane valve body, 5 is a nickel-plated terminal cap made of stainless steel having a thickness of 0.15 mm, 6 is a flange portion of the terminal cap, and 7 is nickel-plated. A 0.2 mm-thick stainless steel bottom plate provided with a through hole at the bottom is used for assembling these as shown in FIG. First, the leg portion of the hollow rivet 3 is inserted into the through hole at the bottom of the valve body holding plate 7, and the membrane valve body 4 and the terminal cap 5 are installed on the seat of the hollow rivet 3. Then, the opening edge portion of the valve element holding plate 7 is caulked inward, and the membrane valve element 4 and the flange portion 6 of the terminal cap 5 are fastened and fixed.

Near the center of the terminal cap 5, the terminal cap 5 is bent in a direction opposite to the direction of the membranous valve body 4 to form a top hat. Further, at the center of the terminal cap 5, there is a cutting blade 8 and a gas vent hole 9 which are bent toward the above-mentioned membrane valve body 4, and the tip portion of the cutting blade 8 and the surface of the membrane valve body 4 are provided. The distance to and is 0.5 mm. The cutting blade 8 and the gas vent hole 9 are formed by cutting a portion corresponding to two sides of a triangle in the central portion of the terminal cap 5 and bending the triangular cut portion toward the membrane valve body 4 side. It is formed.

The membranous valve element 4 is made of a laminate of a 20 μm-thick aluminum thin metal plate and a 50 μm-thick heat-fusion resin film. This heat-fusible resin film is made of polypropylene-based resin in which 6% by weight of maleic anhydride is graft-polymerized to polypropylene to give a fusion property to a metal.

Next, the metal sealing lid 2 is sandwiched between the insulating packing 10 and the insulating packing 11 made of polypropylene resin from above and below, and the membrane valve body 4 and the flange portion 6 of the terminal cap 5 are clamped by the valve body clamping plate 7. The hollow rivet 3 thus prepared is inserted into the through holes 14 of the insulating packings 10 and 11, and the washer 13 for current collection made of aluminum is inserted into the through hole 14 of the insulating packing 10, and the whole is vertically pressed to vertically press the whole leg of the hollow rivet 3. Expand and crimp.

The battery was assembled as described above.

In the embodiment, the film-shaped valve body is made of a laminate of a resin film and a metal thin plate, but may be a metal thin plate such as an aluminum thin plate, a nickel thin plate or a stainless steel thin plate.

Further, the insulating member 10 and the insulating member 11 may be coated with a sealing material such as blown asphalt in order to increase airtightness.

[0024]

[Effect of device]

 As described above, according to the present invention, it is possible to obtain a prismatic sealed battery having a safety valve device with good pressure responsiveness and excellent liquid leakage resistance, and its practical value is extremely large. Is.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a sealed battery according to an embodiment of the present invention.

FIG. 2 is an assembly view of a membrane valve body according to an embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a conventional sealed battery.

FIG. 4 is a sectional view of a main part of a conventional sealed battery.

FIG. 5 is a sectional view of a main part of a conventional sealed battery.

FIG. 6 is a sectional view of a main part of a conventional sealed battery.

[Explanation of symbols]

 1 Exterior Can 2 Metal Sealing Lid 3 Hollow Rivet 4 Membrane Valve Body 5 Terminal Cap 6 Terminal Cap Flange 7 Membrane Valve Body Clamping Cap 8 Cutting Edge 9 Gas Venting Hole 10 Upper Insulating Packing 11 Lower Insulating Packing 12 Through Hole 13 Collection washer 14 Through hole

Claims (1)

[Scope of utility model registration request] 1. An outer can (1) which also functions as a unipolar terminal and which houses a power generating element, a metal sealing lid (2) which is electrically conductively fixed to the outer can and closes the opening of the outer can, and the metal sealing. In a prismatic sealed battery in which a hollow rivet (3) of another polarity terminal is attached to a through hole provided in a part of a lid via an insulating member, a membranous valve element (is attached to the seat of the hollow rivet (3). 4) is installed, the through hole (12) of the hollow rivet (3) is always closed by the membrane valve body (4), and the terminal cap (5) is installed on the membrane valve body (4). A corner characterized in that the hollow rivet (3), the membrane valve body (4) and the flange portion (6) of the terminal cap (5) are caulked and fixed by caulking by the valve body holding plate (7). Type sealed battery.