JP3069760B2 - Square sealed battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular sealed battery.

[0002]

2. Description of the Related Art Nickel-metal hydride batteries (nickel-cadmium secondary batteries) have been replaced by nickel-metal hydride batteries. This nickel-metal hydride battery uses nickel for the positive electrode and a hydrogen-absorbing alloy for the negative electrode, has a higher energy capacity per unit volume than the nickel-cadmium battery, and has various characteristics such as charge / discharge characteristics, quick charge characteristics, and life characteristics. Also has characteristics comparable to those of the NiCd battery.

[0003] By the way, ordinary nickel-cadmium batteries and nickel-metal hydride batteries have a cylindrical shape, so that a dead space is generated when they are stored in a device, and this is a serious problem particularly in a cordless device that is reduced in size and weight. It has become to. For this reason, a rectangular battery has been used in which a dead space is eliminated when the battery is stored in a device, and the battery capacity is increased accordingly.

A rectangular sealed battery has a flat rectangular parallelepiped shape as shown in FIG. 4. For example, the height is the same as the cylindrical battery, the long side 1a is the same length as the diameter of the cylindrical battery, and the short side. 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 generating element 2 (FIG. 5) is fitted into the outer can 1, and after the electrolyte is injected, the sealing body 3 is fitted and mounted on the rectangular upper opening end 1c.
The entire circumference is welded to form a closed structure.

[0005] sealing body 3, the recess in the center as shown in FIG. 5
Shape but with a flat cover plate 4 than to be formed in the center of the cover plate 4
The gasket 5 is inserted into the hole 4a formed in the center of the formed recess.
And the lower end is fixed to the lid plate 4 together with one end of the lead plate 7 to which the anode current collector of the power generation element 2 is connected, and the head thereof rises at the entire peripheral edge of the gasket 5. Rivet 6 whose upper surface is covered with the upper portion and is substantially flush with the upper surface of the cover plate 4 and is exposed, and a small hole 6a is formed in the center.
Are welded and fixed via flanges 8a provided on both sides facing the short sides 1b (FIG. 4) of the outer can 1, respectively, on the upper surface of the head of the rivet 6, and fixed to the long sides 1a. Notch 8 at each lower end of each side face 8b to serve as a gas escape path
c, an anode cap 8, and a safety valve 9 housed in the anode cap 8 and closing the hole 6 a of the rivet 6.

When the internal pressure of the battery rises abnormally for some reason and exceeds a predetermined pressure, the safety valve 9 opens by the gas pressure applied through the hole 6a of the rivet 6, and the gas in the outer can 1 is cut off by the notch 8c of the anode cap 8, 8c to the outside,
Decrease battery internal pressure. The nickel-metal hydride battery has a structure in which gas generated at the time of overcharge is completely consumed inside the battery, but has a safety valve 9 built in in case of an emergency.

[0007]

However, when the cover plate 4 of the sealing body 3 is welded to the open end 1c of the outer can 1, the welded portion of the cover plate 4 is connected to the anode cap 8 on the long side 1a of the outer can 1. The notch 8c of the anode cap 8 due to the influence of heat due to welding, for example, radiant heat, reflected heat in laser welding, and heat of fusion of a combustible material such as a rising portion of the gasket 5 near the welded portion. Through the anode cap 8 to form a safety valve 9 formed of a rubber-based member.
Will melt a part of it. As a result, the effective cross-sectional area of the safety valve 9 decreases, and the pressure (valve opening pressure) to be operated cannot be guaranteed, and the safety valve 9 may operate at a pressure lower than the predetermined pressure. For this reason, there is a possibility that the safety valve 9 is opened during normal use, particularly during normal charging, and the internal electrolyte leaks out, possibly damaging equipment incorporating the battery.

When the rubber-based safety valve 9 melts, a gas containing soot and the like is generated, and is discharged to the outside through the notch 8 c of the anode cap 8. In particular, all or a part of the laser beam L is blocked by the soot-containing gas during laser welding, and condensing is not performed uniformly.
The weld bead on the long side surface 1a side varies, and in some cases, the bead cannot be formed, resulting in poor welding. A gap is generated in the fitting portion between the outer can 1 and the sealing body 3, which causes leakage of the internal electrolyte. There are problems such as becoming.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a rectangular sealed battery that protects a safety valve incorporated in a cap when welding an outer can and a sealing body and prevents poor welding. The purpose is to provide.

[0010]

According to the present invention, in order to achieve the above-mentioned object, a closure is fitted to the open end of a rectangular outer can having an open end in a rectangular shape and is welded over the entire circumference. A square sealed battery, which is disposed at the center of the upper surface of the body, has a built-in safety valve that opens when the internal pressure rises abnormally, and has a cap formed with a gas escape path for discharging the internal pressure to the outside, The escape path is provided on the side of the cap facing the short side of the outer can.

[0011]

When the sealing body fitted to the rectangular opening end of the outer can is welded over the entire circumference, a gas escape path is opened on the side of the cap closest to the welded portion facing the long side of the outer can. The safety valve built into the cap is protected from welding heat. Since the safety valve is protected from the heat of fusion, the fusion is prevented, the generation of gas containing soot and the like is eliminated, and the sealing welding is performed well. As a result, it is possible to manufacture a sealed battery in which the operating pressure of the safety valve is stable and the sealed weld portion is highly reliable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The same members as those in FIG. 4 are denoted by the same reference numerals. Figure 1 is a top perspective view of a prismatic sealed battery according to the present invention, the sealing member 3 is fitted and attached to the open end 1c of the outer can 1, positive electrode cap at the top center of the sealing body 3 1
0 is provided. The anode cap 10 has flanges 10a, 10a formed on both sides facing the short side surfaces 1b of the outer can 1, and a hole is provided substantially at the center of a continuous portion between the flanges 10a, 10a and the side surfaces 10b, 10b. 10c, 1
0c is drilled. These holes 10c serve as escape paths for gas. And the anode cap 10 is used for the outer can 1.
Each side surface 10d facing each long side surface 1a is completely closed.

The anode cap 10 is placed on the bare upper surface of the head of a rivet 6 fitted and mounted via a gasket 5 in a hole 4a of a cover plate 4 as in FIG. 10a are welded and fixed to the upper surface of the head of the rivet 6 and are electrically and mechanically connected. The anode cap 10 has a built-in safety valve (not shown) made of a rubber-based member, and closes the opening end of the gas vent hole 6 a of the rivet 6 . And re
The head of the bed 6 is the rising portion of the entire periphery of the gasket 5.
Covered by

The operation will be described below. When the sealing body 3 is fitted and mounted on the open end 1c of the outer can 1 and laser-welded, the side faces 10d and 10d of the anode cap 10 facing the long side surfaces 1a and 1a of the outer can 1 are closed. The safety valve 9 built in even near the welded portion of the plate 4 is not affected by the heat of welding. On the other hand, the hole 10 of the anode cap 10
c, 10c are open to the short side surfaces 1b, 1b side of the outer can 1. However, the distance from the opening end on the short side 1b side to the hole 10c of the cap 10 is long, so that when the opening end and the cover plate 4 are laser-welded, radiant heat, reflected heat, and rise of the gasket 5 near the welded portion. The heat of melting of the combustible material such as a part does not enter the anode cap 10 through the hole 10c. This protects the safety valve 9 contained in the anode cap 10 when the sealing body 3 is welded.

Further, since the safety valve 9 is not melted when the sealing body 3 is welded, soot-containing gas is not generated from the safety valve 9 and a laser beam is prevented from being interrupted during laser welding. Is done. As a result, the sealing body 3
Is welded to the outer can 1 satisfactorily over the entire circumference, and the electrolyte does not leak from the welded portion. Then, the safety valve 9 has a stable operating pressure and high reliability.

FIG. 2 shows a second embodiment of the anode cap 10 , wherein one end is opened substantially at the center of each flange 10a at the lower end of each side surface 10b so as to face the inside of the anode cap 10, and each multi-end is opened. Open at the tip of each flange 10a
The gas vent passages 10e and 10e are integrally formed, and the inside and the outside of the anode cap 10 communicate with each other to form a gas escape passage. The passages 10e and 10e are long and
The safety valve 9 in the anode cap 10 can be protected when the sealing body 3 is welded because the opening is made facing the short side surface of the outer can 1.

FIG. 3 shows a third embodiment of the anode cap 10 , and the anode cap 1 of the second embodiment shown in FIG.
0 vent passage 10e, bent substantially at a right angle from the middle to 10e, the flange 10a, so as to face the long side of the outer can 1 at substantially the center of 10a is obtained by opening. Since the passages 10f and 10f are long and bent in the middle, the safety valve 9 can be protected during welding, similarly to the anode cap 10 shown in FIG.

[0018]

As described above, according to the present invention, it is possible to protect the safety valve incorporated in the cap at the time of welding the sealing body to the outer can, and to perform good sealing welding. As a result, the operating pressure of the safety valve is stable,
In addition, there is an effect that it is possible to manufacture a highly sealed rectangular sealed battery having a sealed weld portion.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a second embodiment of the anode cap of FIG. 1;

FIG. 3 is a perspective view showing a third embodiment of the anode cap of FIG. 1;

FIG. 4 is a top perspective view of a conventional rectangular sealed battery including an anode cap.

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer can 2 Power generation element 3 Sealing body 4 Cover plate 5 Gasket 10 Anode cap 10c Gas vent hole 10e, 10f Gas vent passage

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-203157 (JP, A) JP-A 63-106060 (JP, U) JP-A 1-115162 (JP, U) JP-A 60-106 3656 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 2 / 12,2 / 04,2 / 30

Claims (1)

(57) [Claims] An opening end of a rectangular outer can having a rectangular shape is fitted at the opening end and arranged at the center of the upper surface of a sealing body welded over the entire circumference, and is opened when an internal pressure rises abnormally. In a rectangular sealed battery having a built-in safety valve and a cap formed with a gas escape path for discharging the internal pressure to the outside, the sealing body has a recess except that a recess is formed at the center.
Punch a flat lid plate in the center of the recess formed in the center of the lid plate.
Rivet fixed by caulking to the hole
And the safety valve are stored and welded to the top of the rivet.
And the gasket is
Standing part on the entire periphery to cover the side of the head of the rivet
And a gas escape passage formed in the cap is provided on a side of the cap facing the short side of the outer can.