JPS5835865A - Manufacture of lithium battery with lead body - Google Patents

Abstract

PURPOSE:To obtain a lithium battery with a lead body which causes no such harm as an internal short circuit by using a negative can to which an auxiliary lead body is attached, folding the auxiliary lead body so that its free end side protrudes from the negative can, and connecting the said free end to a main body. CONSTITUTION:A metallic net 7 is fixed to the inner wall of a negative can 2 by a spot welding, and a negative electrode 5 made of lithium metal is pressed and fixed upon the net 7 so as to hold the electrode 5 and to make part of the net 7 to be electrically connected to the electrode 5. A gasket 6 consisting of a formed synthetic-resin member is closely attached around the outer circumference of the can 2. After a positive electrode 3 made of mixture consisting of manganese dioxide and a conductive auxiliary agent is inserted onto the bottom of a positive can 1, a separator 4 made of a non-woven fabric consisting of polypropylene fiber is placed on the electrode 3. After that, the negative can 2 is attached to the opening of the positive can 1, and the opening of the can 1 is inwardly curled so as to caulk the battery, thereby constituting a battery. An auxiliary lead body 11 is folded on a folding part located near a spot-welding part 12 so as to make its free end to protrude from the can 2, and a main lead body 13 on the negative electrode side is connected to the above free end by a spot welding 14. A main lead body 15 on the positive electrode side is directly connected to the lower surface of the can 1 by a spot welding 16.

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 a very long life and have superior leakage resistance compared to alkaline batteries, etc., so they are
It has been praised as a power source for C memory backup.

In these applications, lead bodies are often directly spot-welded 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, a lithium battery is assembled in advance, and then lead bodies 8.8 are spot-welded to predetermined positions of the anode can 1 and the cathode can 20, respectively.

That is, first, the can bottom K of the anode can 1 is sequentially inserted with the anode 3 mainly made of manganese dioxide, for example, and the separator 4. Separately, a wire mesh 7 is previously fixed to the inner surface of the cathode can 2 by spot welding, and the A cathode 5 made of metallic lithium is crimped and held on a wire mesh 7, and an annular gasket 6 is fitted around the outer periphery of the cathode can 2. This assembly of cathode can 2, cathode 5, and gasket 6 is inserted through the opening of anode can 1,
The opening of the anode can 1 is bent inward and then tightened to complete the assembly of the battery. Thereafter, the lead bodies 8 were fixed to the anode can 1 and the cathode can 2 by spot welding, respectively.

However, this method has a problem when spot welding the lead body 8 to the cathode can 2. That is, normally the cathode can 2
The outermost layer is a nickel layer trap, 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 about 186°C, so when the temperature is raised to the above-mentioned temperature, the cathode 5 near the weld part will partially melt, which will pass through the separator 4 and come into contact with the anode 3, causing an internal short circuit. . Further, as the separator 4, a synthetic fiber nonwoven fabric, a microporous film, or the like is usually used, and the function of the separator 4 is lost due to holes being formed in some parts due to the thermal influence during welding.

To prevent this from happening, remove the cathode can 2.
It is necessary to spot weld the lead body 8 with a small current in a short time, and welding conditions must be strictly controlled. In addition, when spot welding is performed with a small current and in a short time as described above, the welding strength between the cathode can 2 and the lead body 8 is inevitably weak (
Therefore, a connection failure may occur between the two.

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

In order to achieve this object, the present invention arranges an auxiliary lead body on the top surface of the cathode can so as to fit within the diameter of the cathode can before assembling the battery, and welds one end of the auxiliary lead body by spot welding or other method. It sticks to the cathode can. Then, a lithium battery is assembled using this cathode can with an auxiliary lead body, and then the free end side of the auxiliary lead body is folded back using the vicinity of the welded part of the auxiliary lead body as a folding part, and the auxiliary lead body is made to protrude from the cathode can. The main lead body is connected to the free end side 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 has a thin nickel layer 9 on the outside and a thin stainless steel layer 10 on the inside, as shown in FIG. The left end of a rectangular auxiliary lead body 11 made of a thin nickel plate and slightly shorter than the diameter of the cathode can 2 is fixed to the upper surface of the cathode can 2 in advance by spot welding 12 . A battery is assembled using this cathode can 2, but the auxiliary lead body 11 is supplied so as to protrude from the outer periphery of the cathode can 2 so as not to cause any trouble in supplying the cathode can 2 within the automatic battery assembly device. The length and fixing position of the auxiliary lead body 11 are taken into consideration so that the cathode can 2 will not get caught at times, and the auxiliary lead body 11 is closely attached to 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, a wire mesh 7 is fixed to the inner surface of the cathode can 2 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. It will be done.

A gasket 6 made of a synthetic resin molded product is tightly sealed around 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, and a layer 4 made of a nonwoven fabric of polypropylene fibers is placed on the anode 3. The cathode can 2 holding the cathode 5 and gasket 6 is fitted into the opening of the anode can 1, and 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 auxiliary lead body 1
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 1 as a folded part, 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 10 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. If one cut l7 is formed in the center of the rectangular auxiliary lead body 11 along its longitudinal direction, then K
From this, two strip portions 18A.

18B, and a connecting portion 19 that connects both assembled piece portions 18A and i8B on the side opposite to the incision. Then, the end of one of the strips 18A on the notch side is fixed to the cathode can 2 by spot welding 12. In this embodiment as well, the length and fixing position are arranged 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.

Thereafter, as shown in FIG. 8, the area near the spot weld 12 of the auxiliary lead body 11 is folded back, and one strip portion 18B is folded into the other strip portion 18A along the notch 17.
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 has the above-mentioned configuration, 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 connecting the auxiliary lead body and the main IJ-de body, the auxiliary lead body is folded back and protrudes from the cathode can, so the battery does not get in the way when connecting the two, and it is possible to weld the two together. Since the welding point is far away from the cathode when connecting with the welding method, there is no concern that the cathode will melt due to the heat generated during welding.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view for explaining the assembly process of a conventional lithium battery with a lead body, and FIGS. 2 to 6 are for explaining the first embodiment of the present invention. Figures 2 and 3 are a sectional view and a plan view of a cathode can with an auxiliary lead attached, Figure 4 is a sectional view of a lithium battery assembled using the cathode can, and Figures 5 and 6.
The figure shows a front view and a plan view of the main lead body connected to the lithium battery, Figures 7 and 8 are diagrams for explaining the second embodiment of the present invention, and Figure 7 shows the auxiliary lead. FIG. 8 is a plan view of the cathode can with the body fixed thereto, and a perspective view of the lithium battery to which the present lead body is connected. 2...Cathode can, 5...Cathode, 11...
...Auxiliary lead body, 12... Spot welding, 13... Main lead body, 14... Spot welding. -2; 73 towns

Claims (1)

[Claims] Before assembling the battery, an auxiliary lead body is placed on the top surface of the cathode can so that it fits within the diameter of the cathode can, one end of the auxiliary lead body is fixed to the cathode can by welding, and lithium is transferred using the cathode can. After assembling the battery, the free end side of the auxiliary lead body is folded back as a folded part near the welding part of the auxiliary lead body to protrude from the cathode can, and the main lead body is connected to the free end side of the auxiliary lead body. A manufacturing method for a lithium battery with a lead body.