JPS6065443A - Manufacturing method for sealed type battery - Google Patents

Abstract

PURPOSE:To prevent the direct advance of laser beam into the container of a battery and perform welding by irradiating a position separated from a joint surface between the opening end of a battery container and the erected periphery of a battery cover with laser beam at the joint section between them. CONSTITUTION:A battery container 1 is formed by deep-drawing a stainless steel sheet and a battery cover 2 is also made of the stainless steel sheet. While a battery being assembled is fixed to a jig 11 and a joint section between the opening end of the container 1 and the erected periphery of the cover 2 is being irradiated with laser beam 12 from above, welding is performed by rotating the jig one time. In this case, a position separated by l from a joint surface between the opening end 1a of the container 1 and the erected periphery 2a of the cover 2 is irradiated with laser beam 12 and a weld section 9 is formed by melting an end 1a and a periphery 2a. As a result, the inner part of the battery container is not directly irradiated with laser beam 12 and acceptable laser welding is enabled by preventing a thermal adverse effect from being exerted on battery contents.

Description

DETAILED DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a sealed battery in which the battery contents are less likely to deteriorate, in order to improve a method for manufacturing a sealed battery by laser welding the peripheral edge of the battery.

In a battery that requires a high level of airtightness for a long period of time, for example, as shown in FIG.
Fit the battery cover 2 with the glass seal 3, and then close the battery container 1.
A so-called hermetic seal sealing structure is adopted in which the open end of the battery cover 2 and the rising edge of the battery cover 2 are welded together using a laser beam. However, since laser light travels in a very straight line, if there is even a slight gap between the opening end of the battery container 1 and the rising edge of the battery cover 2, the laser light may enter the battery container 1 from there. This will cause undesirable thermal effects on battery contents such as the negative electrode 5 and separator 6 that are housed in the battery container 1.

In order to avoid such thermal effects on the battery contents, the battery lid 2 is press-fitted into the opening of the battery container 1 to ensure close contact between the opening end of the battery container l and the rising edge of the battery lid 2. However, since the battery container is made of stainless steel plate by deep drawing, there are problems with dimensional accuracy, and laser welding involves rotating the battery or directing the laser beam to the open end of the battery container 1. Welding is carried out along the joint between the opening end of the battery container 1 and the rising peripheral edge of the battery cover 2, and welding is carried out over the entire circumference of the joint between the opening end of the battery container 1 and the rising peripheral edge of the battery cover 2. As the battery cover shrinks due to temperature drop in the previously welded part, the battery lid is drawn towards the welded part, and the joint surface of the part to be welded later tends to open up, which prevents the battery contents from deteriorating due to the laser beam as described above. It is difficult to completely prevent this.

Therefore, as seen in Japanese Patent Application Laid-Open No. 58-10364, a laser beam is irradiated obliquely onto the joint surface between the open end of the battery container and the rising edge of the battery cover, and the battery content is determined by direct irradiation of the laser beam. Methods have been proposed to prevent the deterioration of objects.

The present invention has been made to solve the above-mentioned problems using a method different from the above-mentioned proposed method. By laser welding the open end of the battery container and the rising edge of the battery cover by irradiating a laser beam at a position away from the joint surface with the rising edge, the laser beam can directly enter the battery container. The objective was achieved by preventing this.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing a state in which a sealed battery according to the present invention is being manufactured. In the figure, 1 is a battery container formed by deep drawing a stainless steel plate. Reference numeral 2 denotes a battery lid fitted into the opening of the battery container 1. This battery lid 2 has a glass seal 3 formed on the inner circumference of an annular main body portion formed of stainless steel. A metal pipe 4 is welded. 5 is a negative electrode made of lithium, 6 is a separator made of glass fiber non-woven fabric, 7 is a positive electrode made of a carbon porous molded body formed by adding polytetrafluoroethylene as a binder to acetylene black,
Reference numeral 8 denotes a top cover paper made of the same material as the separator 6, which is placed inside the battery container 1, the negative electrode 5 being in contact with the inner peripheral surface of the battery container 1, and the battery container 1 serving as a negative electrode terminal. It also serves a role.

Fig. 3 shows a laser welding method in which the battery being assembled shown in Fig. 1 is fixed to a jig 11, and a laser beam 12 is applied from above.
Welding is performed by irradiating the joint between the open end of the battery container 1 and the vertical edge of the battery lid 2, and then rotating the jig 11 once.

At this time, as shown in detail in FIG. 4, the laser beam 12 is irradiated to a position a distance β away from the joint surface between the open end 1a of the battery container 1 and the rising peripheral edge 2a of the battery cover 2. When the laser beam 12 is irradiated in this way, as shown in FIG. 5, the open end 1a of the battery container 1 and the raised peripheral edge 2a of the battery M2 are melted to form a welded part 9. The open end 1a of the battery container 1 and the rising peripheral edge 2a of the battery M2 are laser welded. However, the laser beam 12 is transmitted to the open end 1a of the battery container 1 and the rising edge 2a of the battery lid 2.
Since the laser beam 12 is irradiated at a position slightly away from the bonding surface within the range where welding is possible, even if the adhesion of the bonding surface is insufficient, the laser beam 12 will not be directly irradiated into the battery container 1. Therefore, the contents of the battery in the battery container 1 are not adversely affected by heat.

The irradiation position of the laser beam is set between the open end of the battery container 1 and the battery lid 2.
The thermal form W of the battery contents (upper cover paper 8
(confirmed by melting by Raded light)
Shown in the table. The thickness of the battery cover 2 is 0. (Imm) The thickness of the battery container 1 was 0.3 mm, and the laser welding was performed using a carbon dioxide gas laser with an output of 1 kW and by rotating the battery at a rotation speed of 8 Orpm.

Table 1 As shown in Table 1, the laser beam irradiation position is set to the battery container 1.
By positioning the battery cover 2 at a distance of 0.2 mm from the joint surface between the open end of the battery cover 2 and the standing edge of the battery lid 2, thermal effects on the battery contents were eliminated.

The irradiation position of the laser beam is set between the open end of the battery container 1 and the battery lid 2.
It is up to you whether to shift it from the joint surface with the second periphery towards the battery container 1 side or towards the battery cover 2 side, but if you shift it towards the battery cover 2 side as shown in the example, the battery cover 2
Since the two periphery edges melt from the inside to the outside, the gap between the joint surfaces is filled, which is preferable.

The irradiation position of the laser beam is set between the open end of the battery container I and the battery lid 2.
The distance from the joint surface with the rising peripheral edge of the ljQ varies depending on the output of the laser beam and the opening time when ljQ is irradiated, but it is usually preferably in the range of 0.15 to 0.25 mm.

By positioning the table slightly away from the table surface, remarkable effects as shown in Table 1 can be produced, but in practice, it is simply a matter of not shifting the irradiation position of the laser beam, and no special equipment is required. In addition, after welding the open end of the battery container 1 and the rising edge of the battery lid 2, the above-mentioned battery is manufactured using thionyl chloride from the metal pipe 4. An electrolytic solution in which lithium aluminum chloride is dissolved is injected, and then a stainless steel positive electrode current collector rod IO is inserted into the pipe 4, its lower end is inserted into the positive electrode 7, and its upper end is welded to the bagob 4,
A sealed battery as shown in FIG. 2 is completed. In this battery, thionyl chloride as an electrolyte solvent simultaneously functions as a positive electrode active material. - In the examples, a case of a thionyl chloride-lithium battery was given as an example, but the present invention is not limited thereto. The present invention can also be applied to inorganic non-aqueous electrolyte-based sealed batteries in which the positive electrode active material is an alkali metal such as lithium and the negative electrode active material, as well as organic electrolyte-based sealed batteries.

[Brief explanation of the drawing]

1 and 2 are partial sectional views showing an example of a sealed battery according to the present invention, with FIG. 1 showing the state during manufacturing and FIG. 2 showing the state after manufacturing. FIG. 3 is a perspective view showing the laser welding method for the battery shown in FIGS. 1 and 2, and FIG. 4 is a joint between the open end of the battery container and the rising edge of the battery lid during laser welding according to the present invention. FIG. 5 is an enlarged sectional view of the main part of the part shown in FIG. 4 after welding. l...Battery container, 1a...Open end of battery container,
2...Battery cover, 2a...Rising peripheral edge of battery cover, 12...Laser light patent applicant Hitachi Maxell Ltd. Figure 3, Figure W4

Claims (1)

[Claims] (11) When manufacturing a sealed battery in which the open end of the battery container and the rising edge of the battery lid are laser welded, the battery lid is fitted into the opening of the battery container, and the open end of the battery container and the rising edge of the battery lid are welded together. The opening end of the battery container and the rising periphery of the battery cover are laser beamed at a position away from the joint surface of the opening end and the rising periphery at the joint with the rising periphery. A method for manufacturing a sealed battery, which involves welding.