JPH07183012A - Square sealed battery - Google Patents

Abstract

PURPOSE:To protect a safety valve when a sealing body of a square sealed battery is welded and surely weld the sealing body. CONSTITUTION:A square sealed battery has a cathode cap 8 which is arranged in the center on the upper surface of a sealing body 3 whose opening end 1c is fi to the opening end of a rectangular, square outer jacket can 1 and whole circumference is welded, and incorporates a safety valve 9 which opens when internal pressure is abnormally increased, and in which a hole 8c which opens along the long side surface 1a side and through which the internal pressure is exhausted to the outside is installed. The welding surface between the opening end of the outer jacket can 1 and the sealing body 3 is inclined toward the outside and obliquely downward against the cathode cap 8.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a prismatic sealed battery.

[0002]

2. Description of the Related Art A nickel hydrogen battery has been adopted as a successor to a nicad battery (nickel cadmium secondary battery). This nickel-metal hydride battery uses nickel for the positive electrode and a hydrogen storage alloy for the negative electrode, and has a higher energy capacity per unit volume than Nicad batteries, and has various characteristics such as charge / discharge characteristics, rapid charging characteristics, and life characteristics. Also has characteristics comparable to Nicad batteries.

By the way, since ordinary Ni-Cd batteries and nickel-hydrogen batteries have a cylindrical shape, a dead space is generated when they are housed in a device, which is a serious problem especially in cordless devices that are small and lightweight. It has become to. Therefore, a prismatic battery has been used in which a dead space is eliminated when the device is stored in a device and the battery capacity is increased accordingly.

The prismatic sealed battery has a flat rectangular parallelepiped shape as shown in FIG. 3, for example, the height is the same as that of the cylindrical battery, and the long side surface 1a is the same as the diameter of the cylindrical battery and the short side surface. 1
The length b is one-third the length of the long side surface 1a, and is formed to have a size corresponding to a space for accommodating one cylindrical battery when three are arranged. Then, the power generation element 2 (FIG. 4) is fitted into the outer can 1, and after the electrolytic solution is injected, the sealing body 3 is fitted and attached to the rectangular upper opening end 1c,
The entire circumference is welded to form a closed structure.

As shown in FIGS. 3 and 4, the sealing body 3 is fitted into a rectangular lid plate 4 and a hole 4a formed in the center of the lid plate 4 in a liquid-tight manner via a gasket 5 to be mounted. The lower end is caulked and fixed to the lid plate 4 together with one end of the lead plate 7 to which the anode current collector of the power generating element 2 is connected, and the upper surface is substantially flush with the upper surface of the lid plate 4 and barely exposed, and a small hole is formed in the center. A rivet 6 having a hole 6a and a rivet 6 placed on the rivet 6 and fixed by welding via flanges 8a provided on both sides of the outer can 1 facing the respective short side surfaces 1b (FIG. 3). It is composed of an anode cap 8 provided with a notch 8c serving as a gas escape path at each lower end of each side surface 8b facing the long side surface 1a, a safety valve 9 which is built in the anode cap 8 and closes a hole 6a of the rivet 6. ing.

The safety valve 9 is opened by the gas pressure applied through the hole 6a of the rivet 6 when the internal pressure of the battery abnormally rises and exceeds a predetermined pressure for some reason, so that the gas in the outer can 1 is cut out 8c in the anode cap 8. 8c to the outside,
Lower the battery internal pressure. The nickel-hydrogen battery has a structure in which the gas generated during overcharging is completely consumed inside the battery, but a safety valve 9 is built-in in case of emergency.

[0007]

However, when the lid plate 4 of the sealing body 3 is welded to the opening end 1c of the outer can 1, the welded portion with the lid plate 4 on the long side surface 1a of the outer can 1 is the anode cap. Since it is closer to the notch 8c of No. 8, the influence of heat due to welding, for example, radiant heat, reflected heat in laser welding, melting heat of combustible material such as the gasket 5 near the welded portion, etc. from the notch 8c of the anode cap 8. Enter the anode cap 8,
Part of the safety valve 9 formed of a rubber member will be melted. As a result, the effective sectional area of the safety valve 9 is reduced, the pressure (valve opening pressure) to be operated cannot be guaranteed, and there is a possibility that the safety valve 9 may be operated at a pressure lower than a predetermined pressure. For this reason,
During normal use, especially during normal charging, the safety valve 9 may open and the electrolyte solution may leak out, damaging the device incorporating the battery.

Further, when the rubber type safety valve 9 is melted, a gas containing soot is generated and discharged from the cutout 8c of the anode cap 8 to the outside. The soot-containing gas blocks all or part of the laser beam L during laser welding, so that light is not uniformly collected. As a result, the welding bead on the long side surface 1 a side of the outer can 1 is formed. And, depending on the case, a bead cannot be formed, resulting in poor welding, and a gap is generated in the fitting portion between the outer can 1 and the sealing body 3, which causes leakage of the electrolytic solution inside.

The present invention has been made in view of the above points, and is a rectangular airtight seal that protects a safety valve built in an anode cap when welding an outer can and a sealing body and prevents welding defects. The purpose is to provide a battery.

[0010]

In order to achieve the above object, according to the present invention, a sealing body is fitted and attached to the opening end of a rectangular outer can whose opening end has a rectangular shape and welded over the entire circumference. An anode cap that is arranged at the center of the upper surface of the anode, has a built-in safety valve that opens when the internal pressure rises abnormally, and has a hole that opens toward the long side of the opening end to discharge the internal pressure to the outside. In the prismatic sealed battery including the above, the welding surface between the opening end of the outer can and the sealing body is an inclined surface that is inclined outward and obliquely downward with respect to the anode cap.

[0011]

When laser welding the long side opening end of the outer can and the sealing body, the reflected light of the laser beam and most of the radiant heat are reflected outward by the welding surface due to the inclined welding surface. Penetration of the cap is greatly reduced. This protects the safety valve built into the anode cap. Further, the soot-containing gas is not generated from the safety valve, the laser beam is not blocked, and the sealing welding is performed well. As a result, it is possible to manufacture a sealed battery in which the working pressure of the safety valve is stable and the sealing welded portion is highly reliable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The same members as those in FIG. 4 are designated by the same reference numerals. FIG. 1 is an upper cross-sectional view of a prismatic sealed battery to which the present invention is applied, in which a sealing body 3 is liquid-tight in a lid plate 4 and a hole 4a formed in the center of the lid plate 4 via a gasket 5. A rivet 6 which is fitted and mounted, and whose lower end is caulked and fixed to the lid plate 4 together with one end of the lead plate 7 to which the anode current collector of the power generating element 2 is connected, and the rivet 6 in which a small hole 6a is formed in the center. An anode cap 8 provided with a notch 8c at substantially the center of each lower end of each side surface 8b fixed and fixed on the outer side surface 1a of the outer can 1 and a hole 6a of a rivet 6 built in the anode cap 8;
It is constituted by a safety valve 9 that closes the valve.

The outer can 1 is formed such that the open end faces 1d of the long side faces 1a on the notch 8c side of the anode cap 8 are inclined outward and obliquely downward at a slight angle α,
When laser-welding the fitting portion of the sealing body with the lid plate 4, welding heat, radiant heat, and the like are reflected outward, that is, in a direction away from the anode cap 8. This inclination angle α is 0.
The range is 1 ° to 3 °.

The range in which the opening end surface 1d of the long side surface 1a is provided with an inclination is sufficient as long as it includes at least the notch 8c of the anode cap 8 and its vicinity, and the vicinity of both ends apart from the anode cap 8 is particularly an inclined surface. No need. However, it is troublesome to make the inclined surface only near the center of the end face 1d of the long side surface 1a, and therefore it is easier to make the inclined surface over the entire length. Further, the open end surface of the short side surface 1b (FIG. 3) of the outer can 1 is also separated from the anode cap 8, and there is almost no influence at the time of welding, and it is not particularly necessary to make it an inclined surface.

The operation will be described below. When the sealing body 3 is fitted and attached to the opening end 1c of the outer can 1, and laser welding is performed, the laser beam L is applied to the fitting portion between the opening end 1d of the long side surface 1a of the outer can 1 and the lid 4, that is, the welding surface. Is irradiated, the fitting portion is welded, and at this time, welding heat and radiant heat are reflected. However, since the end surface 1d of the long side surface 1a is an inclined surface, most of the welding heat and the radiant heat are reflected in a direction away from the anode cap 8 as indicated by an arrow A, that is, outward. As a result, the penetration of the anode cap 8 from the notch 8c is extremely reduced, and the safety valve 9 built in the anode cap 8 is protected from the reflected heat and the radiant heat. This prevents the safety valve 9 from melting.
Therefore, the safety valve 9 has stable operating pressure and high reliability.

Since the melting of the safety valve 9 is prevented, the soot-containing gas is not generated from the safety valve 9, the laser beam is not blocked, and the welding of the outer can 1 and the lid 4 is very good. To be done. As a result, the sealing body 3
Is satisfactorily welded to the outer can 1 over the entire circumference thereof, and the electrolytic solution does not leak from the welded portion. FIG. 2 shows another embodiment of the present invention, in which the end surface 1d of the long side surface 1a of the outer can 1 is an inclined surface and the upper surface 4b of the lid 4 is also an inclined surface having the same inclination angle α as the end surface 1d. The upper end surface 1d of the long side surface 1a and the upper surface 4b of the lid 4 are continuous inclined surfaces. In this way, by making the upper end surface 1d of the long side surface 1a and the upper surface 4b of the lid body 4 continuous, the welding heat and radiant heat of the welded portion can be more effectively reflected to the anode cap 8 to the outside. Therefore, the safety valve 9 built in the anode cap 8 can be better protected.

[0017]

As described above, according to the present invention, it is possible to protect the safety valve built in the cap when welding the sealing body to the outer can and to perform good sealing welding. As a result, the working pressure of the safety valve is stable,
Moreover, there is an effect that it is possible to manufacture a prismatic sealed battery with a highly reliable sealing weld.

[Brief description of drawings]

FIG. 1 is a top sectional view of a prismatic sealed battery according to the present invention including an anode cap.

FIG. 2 is a top sectional view of a prismatic sealed battery according to another embodiment of the present invention.

FIG. 3 is a top perspective view of a conventional prismatic sealed battery including an anode cap.

4 is a sectional view taken along the line IV-IV in FIG.

[Explanation of symbols]

 1 Exterior Can 2 Power Generation Element 3 Sealing Body 4 Lid Plate 5 Gasket 8 Anode Cap 8c Notch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ken Saito Ken Jobanshita, Iwaki-shi, Fukushima Prefecture Hashidashi, Funao-cho 23-6 Furukawa Battery Co., Ltd. Iwaki Plant (72) Naoyoshi Hinotsu Jobanshita, Iwaki-shi, Fukushima Prefecture 23-6, Furukawa Battery Co., Ltd. Iwaki Plant

Claims (3)

[Claims] 1. A valve is provided at the center of the upper surface of a sealing body that is fitted and attached to the opening end of a rectangular outer can whose opening end is rectangular and welded over the entire circumference, and opens when the internal pressure rises abnormally. In the prismatic sealed battery having a built-in safety valve and facing the long side of the opening end and having a hole for discharging the internal pressure to the outside, the opening end of the outer can and the sealing A prismatic sealed battery, wherein a welding surface with a body is an inclined surface which is inclined outward and obliquely downward with respect to the anode cap. 2. The prismatic sealed battery according to claim 1, wherein the inclined surface is an open end surface of a long side surface of the outer can. 3. The prismatic sealed battery according to claim 1, wherein the inclined surface is an open end surface of a long side surface of the outer can and an upper surface of the sealing body facing the long side surface.