JPH0714558U - Square sealed battery - Google Patents

Abstract

(57) [Summary] [Purpose] Having a safety valve device with good pressure response, and
(EN) A square sealed battery having excellent liquid leakage resistance. [Structure] A hollow rivet (3) of another polarity terminal is disposed in a through hole provided in a part of a metal sealing lid (2) through an insulating member. Hollow rivet seat and flange on terminal cap (7)
(8) and are joined and fixed. The through hole (12) of the hollow rivet is closed by the membrane valve body (10) made of a laminate of a heat-fusible resin film and a thin metal plate.

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]

 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.

At present, sealed batteries are roughly classified into a cylindrical type and a rectangular type due to the difference in shape. Since the cylindrical sealed battery has a circular portion in its cross section, when mounted in a device, there is a lot of waste in the storage part due to its volume. From the viewpoint of effectively utilizing a small space, it is preferable to use a rectangular closed 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 the conventional cylindrical sealed battery, as shown in FIG. 3, a sealing body 28 provided with a film-like valve body 23 is provided with a cylindrical exterior body that also serves as a unipolar terminal having a power generation element built in via an insulating member 22. Generally, the can 21 is caulked and fixed by the opening edge. In the figure, 24 is a sealing plate, 25 is an exhaust hole, 26 is a terminal cap, and 27 is a gas vent hole.

However, in the case of the prismatic sealed battery, the opening of the outer can becomes square and the shape of the insulating member also becomes square, so that it is technically difficult to crimp, and the crimp is difficult. However, since it is difficult to crimp with a uniform force like a circular insulating member, there is a drawback that the liquid leakage resistance is poor.

[0008] Therefore, as an example of what is adopted for a prismatic sealed battery, a hermetic structure using an insulating member 33 such as a glass seal or a ceramic seal is adopted as shown in FIG. 4, 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.

The battery structure shown in FIG. 5 is, as described in Japanese Utility Model Publication No. 4-4359, an essential part of the structure of a square sealed battery in which an exhaust valve element is used as a safety valve. The metal sealing lid 52 is sandwiched from above and below by the insulating packing 54 and the insulating packing 55, the hollow rivet 53 is inserted into the through hole 59 of the insulating packing, and the washer 56 for current collection is inserted from the lower part thereof, and the whole body is vertically oriented. Apply pressure to and expand and crimp the leg tips of the hollow rivet.

Next, the exhaust valve element 60 is placed on the seat of the hollow rivet 53, and the flange 58 of the terminal cap 57 and the seat of the hollow rivet 53 are spot-welded while pressing the terminal cap 57 from above. The lid 61 is obtained as described above. Incidentally, 51 is an outer can.

[0012]

[Problems to be solved by the device]

 However, although this structure can be equipped with a safety valve with particularly good pressure response, a gap is easily created between the exhaust valve body and the seat of the hollow rivet, and moisture in the outside air penetrates into the battery and There is a problem with the leakage resistance, which promotes the deterioration of the electrolyte and the electrolyte, and also causes the electrolyte to leak from the gap.

[0013]

[Means for Solving the Problems]

 The present invention is provided with an outer can that also incorporates 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 of another polarity terminal is placed through an insulating member through a transparent hole, a hollow membrane of a heat-fusible film and a thin metal plate is used as a transparent valve of the hollow rivet in the seat of the hollow rivet. The above problem is solved by closing the hole.

[0014]

[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 through hole of the hollow rivet is normally closed by the membrane valve, it has excellent resistance to liquid leakage.

[0015]

【Example】

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

FIG. 1 is a 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 denotes a hollow rivet made of aluminum. The metal sealing lid 2 is sandwiched from above and below by an insulating packing 4 and an insulating packing 5 made of polypropylene resin, and the hollow rivet 3 is inserted into the through holes 11 of the insulating packings 4 and 5. The washer 6 for current collection made of aluminum is inserted into the lower part of this, and the whole is vertically pressed to expand and crimp the leg tips of the hollow rivet 3. Reference numeral 12 is a through hole.

Then, as shown in FIG. 2, a membranous valve body 10 in which a heat-fusible resin film 10 b having a thickness of 50 μm is bonded to a metal thin plate 10 a having a thickness of 20 μm is heat-sealed to a seat of the hollow rivet 3. . Then, the flange 8 of the terminal cap 7 having the gas vent hole 9 on the seat of the hollow rivet 3 was laser spot welded to obtain the lid 13.

The membranous valve body 10 is formed by integrally bonding the heat-fusible resin film 10b and the aluminum thin metal plate 10a by heat bonding with a hot roller. The heat-fusible resin film 10b is made of polypropylene-based resin in which 6% by weight of maleic anhydride is graft-polymerized to polypropylene so as to have a metal-fusible property.

The terminal cap 7 is made of nickel-plated stainless steel SUS304 having a thickness of 0.2 mm, and the vicinity of the center thereof is bent in a direction opposite to the membranous valve body 10 to form a top hat shape. ing.

The battery was assembled as described above.

In this embodiment, a 20 μm aluminum thin plate was used as the metal thin plate, but similar characteristics were obtained with a stainless thin plate having a thickness of 7 μm to 10 μm and a nickel thin plate having a thickness of 5 to 10 μm.

Further, in this embodiment, the polypropylene resin is used as the heat-fusible resin film of the membrane valve element, but a polyethylene resin may be used.

[0023]

[Effect of device]

 From the above, according to the present invention, it is possible to obtain a sealed battery having a safety valve device with good pressure response and excellent leak resistance, and its practical value is extremely large. .

[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 a membranous 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.

[Explanation of symbols]

 1 Outer Can 2 Metal Sealing Lid 3 Hollow Rivets 4 Upper Insulating Packing 5 Lower Insulating Packing 6 Current Collection Washers 7 Terminal Caps 8 Flange 9 Gas Venting Hole 10 Membrane Valve 10a Metal Sheet 10b Thermal Adhesive Resin Film 11 Through Hole 12 Through Hole 13 Lid Body 21 Exterior Can 22 Insulation Member 23 Membrane Valve 24 Sealing Plate 25 Exhaust Hole 26 Terminal Cap 27 Gas Venting Hole 28 Sealing Body 31 Exterior Can 32 Metal Sealing Lid 33 Insulation Member such as Glass or Ceramic Seal 34 Terminal pin 41 Outer can 42 Thin part 51 Outer can 52 Metal sealing lid 53 Hollow rivet 54 Insulating packing 55 Insulating packing 56 Current collecting washer 57 Terminal cap 58 Gas vent hole 59 Through hole 60 Exhaust valve body 61 Lid body

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[Procedure amendment]

[Submission date] January 26, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 3]

[Figure 1]

[Figure 4]

[Figure 5]

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. A hollow rivet (3) of another polarity terminal arranged via an insulating member is attached to a through hole provided in a part of the lid, and a seat of the hollow rivet (3) and a flange (8) of the terminal cap (7). ) Is bonded and fixed to the heat sealed resin film (10a) and the metal thin plate (10).
A prismatic sealed battery characterized in that the through hole (12) of the hollow rivet (3) is closed by the membrane valve body (10) made of the laminate of b).