JP2001229898A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to decrease the erroneous drilling at the welded position by the use of laser welding either between the mouth plate and the battery case, or between the reinforcing plate and the battery case. SOLUTION: A protruding portion is installed at a part of an insulating plate made of resin positioned near a part welded with a laser, and of a face which contacts with the battery case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reduction of welding failure of a battery using laser welding for welding a periphery of a sealing plate and a case or a reinforcing plate and a case.

[0002]

2. Description of the Related Art In recent years, with the spread of various portable devices, sealed storage batteries have been widely used, and nickel cadmium batteries, nickel hydrogen batteries, and lithium secondary batteries are representative. In particular, in recent years, with the downsizing of devices, the spread of prismatic storage batteries has been remarkable.

[0003] As an example of the structure of a prismatic battery, an electrode group composed of positive and negative electrodes and a separator is housed in a battery case.
There is a structure in which the sealing plate is laser-welded to the case opening and sealed, or after the electrode group is stored in the case, for the purpose of reinforcement, the reinforcing plate is connected to the case by laser welding,
There is a structure in which a sealing plate is sealed in a case opening by a crimp method.

[0004] On the other hand, batteries used in portable equipment are sometimes used in the market under severe conditions where a drop impact or repeated vibration is applied. In such a case, the electrode group repeatedly moves and vibrates inside the battery, and the lead portion protruding from the upper part of the electrode group deforms, and inside the case or
Contact with the end of the electrode plate above the electrode group causes a so-called internal short circuit of the battery. In order to prevent this, a resin insulating plate is generally provided between the electrode group and the sealing plate or between the electrode group and the reinforcing plate (Japanese Patent Application Laid-Open No. 10-284110,
JP-A-11-25993).

[0005]

However, the conventional insulating plate has an outer periphery formed along the inner surface of the case.
Since the inner surface of the case and the outer peripheral surface of the insulating plate were in close contact, when laser welding the case opening and the sealing plate or laser welding the case and the reinforcing plate, heat during laser welding was transmitted to the case, A portion of the insulating plate that was in contact with the melt was melted and flowed into the laser weld.

[0006] Since the resin of the insulating plate that has flowed in is instantaneously evaporated by heat during laser welding, a perforated portion (so-called blowhole) is generated in the welded portion, and the electrolytic solution inside the battery is discharged from the perforated portion. There was a problem of liquid leakage.

The present invention solves the above-mentioned problems, and when a battery is formed by using laser welding, dissolution of a resinous insulating plate disposed near a laser-welded portion is prevented. The purpose of the present invention is to provide a battery having excellent laser weld reliability.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve this problem, a battery according to the present invention is provided with a protrusion on a surface of a resinous insulating plate arranged near a laser welded portion in contact with a battery case. By reducing the contacting parts, during laser welding of the case and the sealing plate or laser welding of the case and the reinforcing plate, the melting of the resinous insulating plate due to the heat transmitted to the case is reduced, and the resin It prevents the inflow, and prevents poor perforation of the welded portion.

As a first embodiment, there is provided a battery in which an insulating plate and a reinforcing plate are disposed between an electrode group and a sealing plate in a battery case, and the battery case and the reinforcing plate are laser-welded.
A projection is provided on a part of the surface of the insulating plate that contacts the battery case.

As a second embodiment, there is provided a battery in which an insulating plate is disposed between an electrode group in a battery case and a sealing plate, and the battery case and the sealing plate are laser-welded. The protrusion is provided on a part of the surface in contact with the battery case.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 3 is a schematic sectional view of a prismatic lithium secondary battery in which an insulating plate of the present invention is arranged. In FIG. 3, reference numeral 1 denotes a metallic battery case. Reference numeral 2 denotes a metallic sealing plate fixed to the upper portion of the case 1 via a gasket 3 having electrical insulation and airtightness. Reference numeral 4 denotes a reinforcing plate fixed to the case 1 by laser welding, and reference numeral 5 denotes an electrode group including a positive electrode, a negative electrode, and a separator. A positive electrode lead 6 and a negative electrode lead 7 are provided between the electrode group 5 and the sealing plate 2. The number of the insulating plate of the present invention is eight. As shown in the figure, the upper part of the insulating plate 8 is fixed to the reinforcing plate 4 and the lower part thereof is pressed against the electrode group so as to be in close contact with the electrode group to suppress the movement of the electrode group in the case.

FIG. 1A shows an insulating plate 8 used in the present embodiment, and another shape shown in FIG. 1B is conceivable.

The lithium secondary battery provided with the insulating plate of FIG. 1A was designated as battery A of the present invention, and the battery provided with the conventional insulating plate shown in FIG. 2 was designated as a comparative battery. It is shown in (Table 1).

[0015]

[Table 1]

As is clear from Table 1, the battery of the present invention has an excellent effect in reducing defective laser welding holes.

Example 2 FIG. 4 shows a cross section of a prismatic nickel-metal hydride storage battery. Reference numeral 11 denotes a nickel-plated iron battery case, a positive electrode plate using nickel hydroxide as a positive electrode active material, and a negative electrode active material. Electrode group 12 constituted by inserting a negative electrode plate using a hydrogen storage alloy through a nonwoven fabric separator made of polypropylene, into an insulating plate 13 of the present invention shown in FIG.
Is installed, an aqueous solution of potassium hydroxide having a concentration of 1.3 mol / l is injected as an electrolytic solution.

Thereafter, the nickel current collecting lead 14 taken out of the positive electrode plate is resistance-welded to a nickel-plated iron washer 15. Reference numeral 16 denotes a rivet also serving as a nickel-plated iron terminal, which is swaged with a washer 15 via an insulating gasket 17 made of resin. Finally, 18 sealing plates were arranged at the opening of the rectangular case, and the periphery of the sealing plate was welded and sealed by laser welding.
And

A battery similar to the above was prepared except that the battery was constituted by the conventional insulating plate shown in FIG. 2, and this was used as a comparative battery.

Table 2 shows the occurrence rate of perforation defects due to laser welding at this time.

[0021]

[Table 2]

As is evident from Table 2, the battery of the present invention has an excellent effect in terms of reducing the defects of laser welding holes in the sealing plate.

[0023]

As described above, according to the battery of the present invention, the projection is provided around the resinous insulating plate disposed near the laser welded portion, and the portion in contact with the battery case is reduced, so that the battery case is reduced. During laser welding of the sealing plate and the sealing plate or laser welding of the case and the reinforcing plate, the melting of the resinous insulating plate due to the heat transmitted to the case is reduced, preventing the resin from flowing into the welded part, and the hole opening defect of the welded part And a battery with excellent laser weld reliability can be provided.

[Brief description of the drawings]

1A is a perspective view showing an insulating plate of the present invention, and FIG. 1B is a perspective view showing another insulating plate of the present invention.

FIG. 2 is a perspective view showing a conventional insulating plate.

FIG. 3 is a cross-sectional view showing a lithium secondary battery on which the insulating plate of the present invention is disposed.

FIG. 4 is a sectional view showing a nickel-metal hydride battery on which the insulating plate of the present invention is arranged.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 battery case 2 sealing plate 3 gasket 4 reinforcing plate 5 electrode group 6 positive electrode lead 7 negative electrode lead 8 insulating plate 11 battery case 12 electrode group 13 insulating plate 14 current collecting lead 15 washer 16 rivet 17 insulating gasket 18 sealing plate

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshimi Shinomiya 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Terms (Reference) 5H011 AA09 DD13 DD21 5H040 AA18 JJ00

Claims (3)

[Claims] 1. A battery, comprising: a battery case accommodating an electrode group having a separator disposed between a positive electrode plate and a negative electrode plate; and a sealing plate sealing an opening of the battery case. A battery in which a protrusion is provided around a resinous insulating plate disposed near a welded portion. 2. A battery case for accommodating an electrode group having a separator disposed between a positive electrode plate and a negative electrode plate, and a sealing plate for sealing an opening of the battery case, wherein an insulating plate is provided between the electrode group and the sealing plate. A battery in which a reinforcing plate is provided and the battery case and the reinforcing plate are laser-welded, wherein the projecting portion is provided on a part of a surface of the insulating plate in contact with the battery case. 3. A battery case accommodating an electrode group having a separator disposed between a positive electrode plate and a negative electrode plate, and a sealing plate sealing an opening of the battery case. An insulating plate is provided between the electrode group and the sealing plate. A battery in which the battery case and the sealing plate are laser-welded, wherein a protrusion is provided on a part of a surface of the insulating plate in contact with the battery case.