JP3149010B2 - 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 structure of a rectangular sealed battery, and more particularly to a structure of an insulating plate interposed between an upper sealing portion of a metal square case and a positive terminal cap of a sealing plate having a safety device. .

[0002]

2. Description of the Related Art In recent years, as AV devices and communication devices have become smaller and lighter, there has been a demand for the development of smaller and more space-efficient batteries. Under such circumstances, the demand for a prismatic sealed battery with good storage efficiency in equipment has been rapidly increasing. These prismatic sealed batteries are
As shown in FIG. 1, an open end 2 of a rectangular case 2 made of stainless steel or nickel-plated steel plate in which a power generating element 1 is housed.
A sealing plate 3 is fitted and mounted, and a fitting portion is welded by a laser welding machine to form a liquid-tight structure. The sealing plate 3 has an anode rivet 5 fixed via an insulating packing 4.
And a positive electrode terminal cap 7 having a lower end welded and fixed to the upper end of the anode rivet 5 and a safety device 6 incorporated therein. After the sealing plate 3 is welded, an insulating plate 8 is interposed between the sealing plate 3 and the positive electrode terminal cap 7, and the positive electrode terminal cap 7 has a small gap G (0.1 mm or less) over the entire circumference in the hole 8a. ) And heat-shrinkable exterior resin tube 9
Thus, the rectangular case 2 and the insulating plate 8 are integrally coated. The upper surface of the exterior resin tube 9 is opened slightly larger than the hole 8a of the insulating plate 8, and the upper surface of the positive electrode terminal cap 7 is slightly higher and bare.

[0003]

However, in the rectangular sealed battery having the above structure, a gap G (0.1 mm or less) is provided over the entire circumference between the positive electrode terminal cap 7 and the hole 8a of the insulating plate 8. The open end 2a of the square case 2
When the insulating plate 8 is interposed between the insulating plate 8 and the positive electrode terminal cap 7 of the sealing plate 3, the insulating plate 8 is easily dropped or displaced due to vibrations or other causes during the battery manufacturing process, resulting in heat. There is a problem that poor covering of the shrinkable exterior resin tube 9 occurs.

In the case where the insulating plate 8 is bonded and fixed to the sealing plate 3 in order to prevent the insulating plate 8 from dropping or displacing in the covering step with the exterior resin tube 9, an adhesive is applied after the bonding step or bonding. There is also a problem that a drying process for drying is required, and the battery manufacturing process becomes complicated.
The present invention has been made in view of the above points, and an object of the present invention is to provide a rectangular sealed battery in which a manufacturing process is simplified and coating defects of a heat-shrinkable exterior resin tube are significantly reduced. .

[0005]

According to the present invention, a rectangular case accommodating a power generating element is provided.
A positive electrode terminal cap is provided and a sealing plate fitted and fixed to the opening end of the rectangular case, and the positive electrode terminal cap placed on the sealing plate is inserted with a slight gap and the head is slightly In a rectangular sealed battery provided with an insulating plate provided with a hole that protrudes, and a heat-shrinkable exterior resin tube that integrally covers the rectangular case and the insulating plate, an inner surface of the insulating plate opposite to the hole is provided. And a configuration in which projections are provided to abut against opposing outer surfaces of the positive electrode terminal cap.

[0006]

When the insulating plate is mounted on the sealing body, the projections formed on the opposite inner surfaces of the holes into which the positive electrode terminal caps are fitted abut against the side surfaces of the positive electrode terminal caps. This allows the insulating plate to be accurately positioned and held by the positive electrode terminal cap, thereby preventing the insulating plate from falling off and being displaced when covering the heat-shrinkable exterior resin tube. As a result, the rate of occurrence of coating defects becomes extremely small.

[0007]

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 shown in FIG. 1 are denoted by the same reference numerals. In FIG. 2, a rectangular case 2 is formed in a flat rectangular parallelepiped shape from stainless steel or nickel-plated steel plate, and a power generation element 1 is housed inside. A sealing plate 3 is fitted to the open end 2a of the rectangular case 2, and the fitted portion is welded over the entire circumference by a laser welding machine to form a liquid-tight structure. The positive electrode terminal cap 7
The anode rivet 5 has a cylindrical shape with a lid, and has a lower end welded to a hole 3a provided at the center of the sealing plate 3 through an insulating packing 4 in a liquid-tight manner and fixed by caulking to an upper end of a cylindrical anode rivet 5. .

The safety device 6 incorporated in the positive electrode terminal cap 7 is a valve element formed of a rubber member, and is opened when the internal pressure of the battery exceeds a predetermined pressure.
The internal pressure is discharged to the outside from an opening (not shown) provided at the lower end of both side walls of the battery to protect the battery. The insulating plate 10 has the same shape as the outer shape of the opening end 2a of the rectangular case 2 and is formed to have a plate thickness slightly lower than the height of the positive electrode terminal cap 7, and has a positive electrode terminal in the center as shown in FIG. Square hole 10a slightly larger than cap 7
Is provided. The square hole 10a is set to be larger than the positive electrode terminal cap 7 by 0.1 mm or less over the entire circumference. Then, the inner surface 10 facing the square hole 10a
b , 10c, a projection 10 is provided substantially at the center near the upper open end.
d and 10e are formed facing each other. These projections 1
As shown in FIG. 3, 0d and 10e each have a curved surface having a convex end, and a height h of projection from each inner surface is 0.1 mm.
It is set in the range of 0.3 mm.

The insulating plate 10 is placed on the sealing plate 3, the positive terminal cap 7 is fitted into the hole 10a, and the projections 10d and 10e abut on the opposing surfaces of the positive terminal cap 7. The rectangular case 2 is integrally covered with a heat-shrinkable exterior resin tube 9. The procedure in the manufacturing process of the insulating plate 10 and the heat-shrinkable exterior resin tube 9 will be described below.

After the sealing plate 3 having the positive electrode terminal cap 7 is fitted and welded to the open end 2a of the rectangular case 2 in which the power generating element 1 is housed, the insulating plate 10 is placed on the sealing plate 3. The positive electrode terminal cap 7 is inserted into the hole 10a. At this time, the tips of the protrusions 10d and 10e formed on the inner surfaces 10b and 10c of the hole 10a abut against the opposing side surfaces 7b and 7c of the positive electrode terminal cap 7 with a slight pressing force. As a result, the insulating plate 10 is locked and held by the positive electrode terminal cap 7, is prevented from dropping from the sealing plate 3 or being displaced, and is accurately positioned and held on the insulating plate 10.

Next, the rectangular case 2 and the insulating plate 10 are integrally covered with a heat-shrinkable exterior resin tube 9. The exterior resin tube 9 has an upper surface slightly larger than the hole 10a of the insulating plate 10, and the upper surface (head) 7a of the positive electrode terminal cap 7 and the periphery of the hole 10a are exposed.
The upper surface 7a of the positive electrode terminal cap 7 is slightly higher than the upper surface of the exterior resin tube 9.

As described above, the insulating plate 10 has the hole 10a slightly larger than the positive terminal cap 7 over the entire circumference (0.
The tip of two projections 10d and 10e formed opposite to the inner surface of the hole 10a is in contact with the side surface of the positive electrode terminal cap 7 with a slight pressing force. A slight gap G is formed between each inner surface excluding the portion of 10e and each opposing outer surface of the positive electrode terminal cap 7.
(0.1 mm or less) is formed. Thus, when the battery internal pressure exceeds a predetermined pressure and the safety device 6 operates, the internal pressure is discharged to the outside through the gap, and the battery is protected.

When the hole 10a of the insulating plate 10 is formed slightly larger (0.1 mm or less) over the entire circumference than the positive electrode terminal cap 7, if the height h of the projections 10d and 10e is less than 0.1 mm, the battery manufacturing process When the insulating plate 10 is dropped or misaligned in the inside, when it exceeds 0.3 mm, poor fitting to the positive electrode terminal cap 7 is seen. FIG. 4 is a graph showing the height dimensions of the protrusions 10d and 10e and the occurrence rate of coating defects due to the detachment and displacement of the insulating plate 10.

Here, each of the rectangular sealed batteries is formed by using the insulating plate 10 according to the present invention and the conventional insulating plate 8 shown in FIG.
Table 1 shows the results of comparing the rates of occurrence of defects due to the detachment and displacement of the insulating plates 10 and 8 up to the step of manufacturing 00 pieces and covering with the heat-shrinkable exterior resin tube 9.

[0015]

[Table 1] As is clear from Table 1, during the manufacturing process of the rectangular sealed battery using the insulating plate according to the present invention, the insulating plate has a very large effect of preventing the insulating plate from falling off and the defective coating due to displacement.

[0016]

As described above, according to the present invention, during the manufacturing process of covering the case of the rectangular sealed battery and the insulating plate with the outer resin tube, the insulating plate easily falls due to vibration or other causes. It is possible to prevent the occurrence of misalignment or misalignment, to minimize the rate of occurrence of defective coating of the heat-shrinkable exterior resin tube, and to dry the bonding step and the adhesive for fixing the insulating plate. This eliminates the need for a drying step and the like, and has an excellent effect that the battery manufacturing step can be simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional rectangular sealed battery.

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

FIG. 3 is a plan view of the insulating plate of FIG. 2;

4 is a graph showing the dimensions of protrusions formed on the insulating plate of FIG. 2 and the occurrence rate of coating defects due to dropouts and positional deviations.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation element 2 Square case 3 Sealing plate 4 Insulation packing 5 Anode rivet 6 Safety device 7 Positive electrode terminal cap 9 Heat shrink exterior resin tube 10 Insulation plate

────────────────────────────────────────────────── ─── Continuing from the front page Examiner Masahiro Takagi (56) References JP-A-5-1159 (JP, A) JP-A-7-335190 (JP, A) JP-A 7-27051 (JP, U) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 2/02-2/08

Claims (2)

(57) [Claims] 1. A rectangular case accommodating a power generating element, a sealing plate provided with a positive electrode terminal cap and fitted and fixed to an open end of the rectangular case, and a small positive electrode terminal cap mounted on the sealing plate. A rectangular shape provided with an insulating plate fitted with a gap and having a hole whose head is slightly exposed, and a heat-shrinkable exterior resin tube integrally covering the rectangular case and the insulating plate. The sealed battery according to claim 1, wherein a protrusion is provided on an inner surface of the insulating plate opposite to the hole of the insulating plate, the protrusion being in contact with an outer surface of the positive electrode terminal. 2. The gap between the inner surface of the hole of the insulating plate and the outer surface of the positive electrode terminal cap facing each other is 0.1 mm or less, and the height of each projection from the inner surface is in the range of 0.1 mm to 0.3 mm. The sealed rectangular battery according to claim 1, wherein