JPH0150061B2 - - 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 directly to the Prunt board.

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 cathode 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 if the temperature is raised to the above-mentioned high temperature, the cathode 5 near the weld 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,
Spot welding the cathode can 2 and lead body 8 with a small current.
Welding must be done in a short time, and welding conditions must be strictly controlled. Furthermore, 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 arranges an auxiliary lead body on the top surface of the cathode can with a length that fits within the diameter of the cathode can, and welds one end of the auxiliary lead body to the vicinity of the periphery of the cathode can. After fixing the auxiliary lead body, the cathode can is used to assemble a lithium battery, and then the auxiliary lead body is folded near the welded part and the free end side of the auxiliary lead body is pulled out radially outward of the cathode can, and the auxiliary lead The main lead body is connected to the free side end of the body.

Next, embodiments of the present invention will be described with reference to the drawings. 2 to 6 are diagrams showing a first embodiment of the present invention.

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. The left end of a rectangular auxiliary lead body 11 made of a thin nickel layer and slightly shorter than the diameter of the cathode can 2 is fixed in advance to the upper surface of the cathode can 2 by spot welding 12. This cathode can 2 is used to assemble a battery, but in order to avoid any hindrance to the supply of the cathode can 2 within the automatic battery assembly device,
In other words, the length and fixing position of the auxiliary lead body 11 are taken into consideration so that the auxiliary lead body 11 does not protrude from the outer periphery of the cathode can 2 and cause the cathode can 2 to be caught during feeding. 2
adheres to the outer surface of the

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 wire by spot welding, and a cathode 5 made of metallic lithium is crimped onto the wire mesh 7, so that a part of the wire mesh 7 is electrically connected to the cathode 5 and holds the cathode 5. 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 FIGS. 5 and 6, the free end side of the auxiliary lead body 11 is folded back to protrude from the cathode can 2 by using the vicinity of the spot weld 12 of the auxiliary lead body 11 as a folded part. The main lead body 13 on the cathode side is connected 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.

FIG. 7 and FIG. 8 are diagrams for explaining a second embodiment of the present invention. By forming one cut 17 in the center of the rectangular auxiliary lead body 11 along its longitudinal direction, two strip parts 18 are formed.
A, 18B and both strips 18 on the opposite side of the incision
A connecting portion 19 that connects A and 18B is provided. Then, the end of one of the strips 18A on the incision side is fixed to the cathode can 2 by spot welding 12. In this embodiment as well, the length and fixing position are taken into consideration so that the auxiliary lead body 11 fits within the diameter of the cathode can 2, and when the auxiliary lead body 11 is spot welded 12, it is attached to the top surface of the cathode can 2. They are in close contact as a flat plate.

A lithium battery is assembled in the same manner as in the first embodiment using the cathode can 2 with the auxiliary lead body 11 attached. After that, as shown in FIG.
The area near the spot weld 12 of 1 is folded back as a folded part, and one strip part 18 is folded along the notch 17.
B is extended from the other strip portion 18A, and the main lead body 13 on the cathode side is spot-welded 14 to the free end of the strip portion 18B.

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, welding can be performed reliably, and sufficient welding strength can be obtained. In addition, when welding the auxiliary lead body to the cathode can, for example, as described in Japanese Patent Application Laid-open No. 58-35863, one end of the auxiliary lead body is welded to the center of the cathode can, and the auxiliary lead body is free to be welded. If the end side is raised above the battery plane and welded to the main lead body, the battery will get in the way when the two are connected. In other words, in order to avoid problems with the supply of cathode cans in the automatic battery assembly equipment, the auxiliary lead body should not protrude radially outward from the cathode can, and as mentioned above, the auxiliary lead body should be Since one end is welded to the center of the cathode can, the length of the auxiliary lead body is limited to approximately the radius of the cathode can. Therefore, the auxiliary lead body is short, and since it is welded at the center of the cathode can, the position of the weld between the auxiliary lead body and the main lead body is on the plane of the battery, which makes it difficult to weld them together. Batteries get in the way.

In this regard, in the present invention, one end of the auxiliary lead body is welded near the periphery of the cathode can, and the vicinity of the welded part is used as a folded part to pull out the free end side of the auxiliary lead body to the outside in the radial direction of the battery. The position of the welded part between the and the main lead body can be removed from the flat surface of the battery, so the battery does not get in the way when connecting the two, and when connecting the two by welding etc. Since the welding point is far from the cathode, 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;
2 to 6 are for explaining the first embodiment of the present invention, and FIGS. 2 and 3 are sectional views and plan views of the cathode can to which the auxiliary lead body is fixed, and FIG. 4 is a plan view of the cathode can. A sectional view of a lithium battery assembled using the cathode can, Figures 5 and 6 are a front view and a plan view of the lithium battery with the lead body connected to it, and Figures 7 and 8. 7 is a plan view of a cathode can to which an auxiliary lead body is fixed, and FIG. 8 is a diagram for explaining a second embodiment of the present invention.
The figure is a perspective view of a lithium battery to which this lead body is connected. 2... Cathode can, 5... Cathode, 11... Auxiliary lead body, 12... Spot welding, 13... Main lead body, 14... Spot welding.

Claims (1)

[Claims] 1. An auxiliary lead body 11 of a length that fits within the diameter of the cathode can 2 is placed on the top surface of the cathode can 2, and one end of the auxiliary lead body 11 is fixed near the periphery of the cathode can 2 by welding. A lithium battery is assembled using the cathode can 2, and then the auxiliary lead body 11 is assembled.
The free end side of the auxiliary lead body 11 is pulled out to the outside in the radial direction of the cathode can 2 by using the vicinity of the welded part as the folded part,
The main lead body 1 is attached to the free end side of the auxiliary lead body 11.
A method for manufacturing a lithium battery with a lead body, characterized in that 3 is connected.