JPH023269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a lithium battery with a lead body in which a lead body is connected at least to the cathode can side.

Lithium batteries have an extremely long lifespan and have superior leakage resistance compared to alkaline batteries, so they are widely used as power supplies for IC memory backups. In these applications, lead bodies are often spot-welded directly to the cathode and anode cans of the battery, and the other ends of the lead bodies are soldered to a printed circuit board as they are.

FIG. 1 is a diagram for explaining a conventional manufacturing method of a lithium battery with a lead body. In the conventional method, the lithium battery was assembled in advance, and then the lead bodies 8, 8 were spot-welded to predetermined positions of the anode can 1 and the cathode can 2, respectively.

That is, first, the anode 3 and the separator 4, which are mainly made of manganese dioxide, for example, are sequentially inserted into the bottom of the anode can 1. Apart from this, a wire mesh 7 is fixed to the inner surface of the cathode can 2 in advance by spot welding,
A cathode 5 made of metallic lithium is crimped and held on the wire mesh 7, and an annular gasket 6 is fitted around the outer periphery of the anode can 2. The assembly of the cathode can 2, cathode 5, and gasket 6 is inserted through the opening of the anode can 1, and the opening of the anode can 1 is bent inward and tightened to complete the assembly of the battery. after that,
A lead body 8 is attached to each of the anode can 1 and the cathode can 2.
were fixed by spot welding.

However, in this method, the lead body 8 is attached to the cathode can 2.
There is a problem when spot welding. That is,
Usually, the outermost layer of the cathode can 2 is a nickel layer, and a thin nickel plate is also used as the lead body 8. Therefore, in order to reliably weld the lead body 8 to the cathode can 2, a temperature of around 1500° C. is required, but spot welding under such high temperature conditions has a large thermal effect on the cathode 5. The melting point of metallic lithium is approximately 186°C, so when the temperature is raised to the above-mentioned temperature, the cathode 5 near the weld part will partially melt.
It passes through the separator 4 and comes into contact with the anode 3, causing an internal short circuit. Further, as the separator 4, a non-woven fabric made of synthetic fibers, a microporous film, or the like is usually used, and the function of the separator 4 is lost due to the formation of holes in some parts due to the thermal effects during welding.

To prevent this from happening,
The cathode can 2 and the lead body 8 are spot welded using a small current.
Welding must be done in a short time, and welding conditions must be strictly controlled. When spot welding is performed using a small current and a short time as described above, the welding strength between the cathode can 2 and the lead body 8 inevitably becomes weak, resulting in a poor connection between the two.

An object of the present invention is to eliminate the drawbacks of the prior art and to provide a method for manufacturing a lithium battery with a lead body in which the cathode can and the lead body can be reliably welded, and which does not cause problems such as internal short circuits. be.

In order to achieve this object, the present invention fixes a part of the auxiliary lead body to the outer surface of the cathode can by welding such as spot welding, assembles a lithium battery using the cathode can, and then attaches the auxiliary lead body to the outer surface of the cathode can. The lead body is connected to the lead body by spot welding or the like.

Next, embodiments of the present invention will be described with reference to FIGS. 2 to 5.

The cathode can 2 is made of a clad plate of nickel and stainless steel, and as shown in FIG. 2, a thin nickel layer 9 is disposed on the outside and a thin stainless steel layer 10 is disposed on the inside. One end of a rectangular auxiliary lead body 11 made of a thin nickel plate is fixed in advance to the outer surface of the cathode can 2 by spot welding 12.
This cathode can 2 is used to assemble a battery, but the auxiliary lead body 1 is
1 protrudes from the outer periphery of the cathode can 2 and prevents the cathode can 2 from getting caught during supply.
The length and fixing position of the cathode can 2 are taken into consideration, and the cathode can 2 remains in close contact with the outer surface of the cathode can 2 while remaining flat.

Using this cathode can 2, a button type battery as shown in FIG. 4 is assembled. That is, the cathode can 2
A wire mesh 7 is fixed to the inner surface of the can by spot welding, and a cathode 5 made of metallic lithium is crimped onto the inner surface of the can, and a part of the wire mesh 7 is buried in the cathode 5, thereby creating a connection between the cathode can 2 and the cathode 5. Electrical connections and holding of the cathode 5 are made. A gasket 6 made of a synthetic resin molded product is tightly fitted onto the outer periphery of the cathode can 2 .

On the other hand, an anode 3 made of a mixture of manganese dioxide and a conductive additive is inserted into the bottom of the anode can 1.
A separator 4 made of a nonwoven fabric of polypropylene fibers is placed thereon. Thereafter, the cathode can 2 holding the cathode 5 and gasket 6 is transferred to the anode can 1.
Then, the opening of the anode can 1 is bent inward and tightened to complete the assembly of the battery.

Next, as shown in FIG. 5, the other end of the auxiliary lead body 11 that is not spot welded 12 is bent up and the main lead body 13 on the cathode side is connected to it by spot welding 14. On the other hand, the main lead body 15 on the anode side is directly connected to the lower surface of the anode can 1 by spot welding 16 to obtain a lithium battery with a lead body.

The present invention is constructed as described above, and since the auxiliary lead body is welded to the cathode can before assembling the battery, the heat generated during welding does not affect the cathode or separator. Therefore, internal short circuits do not occur, welding conditions for the auxiliary lead body and the cathode can can be arbitrarily selected, and welding can be performed reliably. Note that when the auxiliary lead body and the main lead body are connected by spot welding or the like, the welding point is separated from the cathode, so there is no concern that the cathode will melt due to the heat generated during welding.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view to explain the assembly process of a conventional lithium battery with a lead;
Figures 2 to 5 are for explaining embodiments of the present invention. Figures 2 and 3 are a sectional view and a plan view of a cathode can to which an auxiliary lead body is fixed, and Figure 4 is a cathode can. FIG. 5 is a cross-sectional view of a lithium battery that has been assembled using a can, and FIG. 5 is a partially cut-away front view of the lithium battery with the lead body connected thereto. 2... Cathode can, 5... Cathode, 11... Auxiliary lead body, 12... Spot welding, 13... Main lead body, 14... Spot welding.

Claims (1)

[Claims] 1. A part of the auxiliary lead body 11 is fixed to the outer surface of the cathode can 2 by welding, a lithium battery is assembled using the cathode can 2, and then the main lead body is attached to the auxiliary lead body 11. 1
A method for manufacturing a lithium battery with a lead body, characterized by connecting 3.