JPS6023955A - Manufacture of cylindrical lithium battery - Google Patents

Abstract

PURPOSE:To fast and uniformly weld a collector net and a negative electrode can by arranging one roller electrode in the negative can and the other roller electrode on the external surface of the negative eletrode can and seam-resistance-welding a collector net on the internal surface of the negative electrode can while the negative electrode can or the roller electrodes are being rotated. CONSTITUTION:A collector net 2 made of stainless steel is contained in a negative electrode can 1 made of stainless steel that is drawn cylindrically with the bottom along the internal surface of the negative electrode can 1 and one roller electrode 21 is contained in the negative electrode can 1 and then the other roller electrode 22 is arranged on the external surface of the negative electrode can 1. Seam resistance welding is performed by simultaneously rotating these two roller electrodes 21 and 22 while the negative electrode can 1 and the collector net 2 are being inserted. In addition, the position of the roller electrodes 21 and 22 is moved the can bottom side and the collector net 2 and the negative electrode can 1 are welded almost all regions by performing seam resistance welding in the same way. For example, the welding conditions are 600gr for applied force 500A for welding current, 20mm./sec for welding speed, and 60rpm for the rotational speed of the roller electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION Accordingly, it is an object of the present invention to quickly and uniformly weld a current collector network on the negative electrode side to the inner circumferential surface of a negative electrode can.

In a cylindrical lithium battery, in order to reduce the contact resistance between the negative electrode can and the lithium, it is necessary to bring the lithium into close contact with the inner peripheral surface of the negative electrode can. Therefore, after inserting a cylindrical lithium into the negative electrode can, the lithium is expanded in the radial direction and crimped onto the inner peripheral surface of the negative electrode can, but the inner peripheral surface of the negative electrode can is originally not uneven. Because it is formed like this, there are no irregularities sufficient to hold lithium, and as a result, the lithium that has once adhered may separate from the inner circumferential surface of the negative electrode can and become an obstacle when inserting the separator or positive electrode. , there are problems such as a decrease in current collection ability on the negative electrode side and an increase in internal resistance.

Therefore, we spot-welded a current collector network to the inner peripheral surface of the negative electrode can.
It has been proposed to press lithium onto this current collection network to increase the adhesion between the negative electrode can and the lithium, but this proposed method
Because the welding is done through welding, the welding strength is not constant, and the mechanical deformation of the current collector network is large due to localized pressure during welding. Other parts rise up, which prevents lithium from being evenly bonded, resulting in a lower current-collecting ability and less effectiveness than expected. In addition, in spot welding, the molten metal adhering to the tip of the electrode must be removed after every 8-point contact in order to be able to perform the next weld, which requires a large number of welding points, such as the welding between the negative electrode can and the current collector grid. It is unsuitable for such cases, and causes a significant decrease in efficiency, as well as variations among products. Furthermore, in the welding process, deterioration over time such as corrosion or cracking is likely to occur at the welding point, which is a major drawback especially in batteries using a highly corrosive electrolyte such as thionyl chloride-lithium batteries.

The present invention solves the above-mentioned drawbacks of the prior art, and in welding the current collecting network to the inner peripheral surface of the negative electrode can, a pair of roller electrodes is used, one roller electrode is placed inside the negative electrode can,
The other roller electrode is placed on the outer circumferential surface of the negative electrode can, and the current collecting network is brought into seam resistance/8 contact with the inner circumferential surface of the negative electrode can without rotating the negative electrode can or the roller electrode, thereby welding the current collecting network and the negative electrode can. This allows the process to be carried out quickly and uniformly.

In other words, in the case of seam resistance/contact as in the present invention,
Unlike spot welding, it is possible to weld continuously, welding can be done quickly, there is little variation between products, and since welding is performed while applying pressure to the welded part with the roller surface, There is no partial lifting of the current collection network, and no corrosion or cracking occurs at welding points. Therefore, even when a highly corrosive electrolytic solution is used, there is no problem, and it is suitable for manufacturing, for example, a cylindrical lithium thionyl chloride battery.

In the present invention, the conditions for seam resistance welding vary depending on the material, shape, dimensions, etc. of the negative electrode can and current collector network, but usually the applied force is 300 to 900 gr, and the welding current is 300 gr.
It is preferable to set the welding speed to 800 A and a welding speed of 10 to 30 mm/sec. Further, in order to perform welding over the entire circumference, it is sufficient to rotate the roller electrode or the negative electrode can, but it is usually easier and preferable to rotate the roller electrode. The rotation speed at this time varies depending on other welding conditions, but is preferably 30 to 90 rpm.

Next, embodiments of the present invention will be described with reference to the drawings.

A stainless steel current collection net 2 is placed in a stainless steel negative electrode can 1 which is deep-drawn into a cylindrical shape with a bottom, along the inner peripheral surface of the negative electrode can 1, and one Coke electrode 21 is placed inside the negative electrode can 1. , the other roller electrode 22 is arranged on the outer peripheral surface of the negative electrode can 1, and seam resistance welding is performed by simultaneously rotating these two roller electrodes 21 and 22 with the negative electrode can 1 and the current collecting net 2 sandwiched therebetween. I did it. The positions of the roller electrodes 21 and 22 were moved to the can bottom side, and seam resistance welding was performed in the same manner as described above to weld the current collection net 2 and the negative electrode can 1 over almost the entire area.

The welding conditions were: applied force 600 gr, welding current 500 A, welding speed 20 mm/sec, and roller electrode rotation speed 6.
It was 0 rpm.

Next, a cylindrical body of lithium 3 is inserted into the negative electrode can 1 with the current collecting network 2 seam resistance welded to the inner circumferential surface as described above, and a rod for expanding the lithium 3 is inserted into the lithium cylindrical body. The cylindrical body is expanded in the radial direction from the inner circumferential side, and the outer circumferential surface is used as the current collection net 2.
And it was crimped onto the negative electrode can 1 (FIG. 3).

After the lithium 3 is brought into close contact with the inner circumferential surface of the negative electrode can 1 via the current collector 11i32 as described above, the expanding rod is pulled up and the isolation paper 4 is placed inside the cylindrical body of the lithium 3 constituting the negative electrode. Insert the separator 5, the positive electrode 6 and the upper separator 7, and then insert the stainless steel pipe 10 into the center of the glass layer 9.
After welding the battery lid 8 and inserting it into the opening of the negative electrode can 1 and welding the outer peripheral edge of the battery lid 8 and the open end of the negative electrode can 1 with a carbon dioxide laser, the electrolytic solution is injected from the pipe 10. ,
After injecting the electrolyte, a stainless steel positive electrode current collector 11 is inserted into the metal vibrator 10, and its lower part is embedded in the positive electrode 6.
The head was welded to the vibrator 10 and sealed to produce a cylindrical lithium thionyl chloride battery as shown in FIG. The positive electrode 6 used was a carbon porous molded body formed by adding polytetrafluoroethylene as a binder and graphite to maintain strength to an acetylene blank.
The electrolytic solution used is lithium aluminum tetrachloride dissolved in thionyl chloride, and thionyl chloride also functions as a positive electrode active material.

In manufacturing the above-mentioned cylindrical lithium battery, the welding between the current collection network 2 and the inner circumferential surface of the negative electrode can 1 is performed quickly and uniformly, and the time required for welding is approximately 1/2 that of conventional groove and groove welding. 3, and no floating of the current collection grid was observed.

It goes without saying that the term lithium used in this specification includes not only lithium itself, but also lithium alloys of lithium and, for example, aluminum, mercury, zinc, cadmium, and the like.

[Brief explanation of drawings]

Figures 1 and 2 schematically show the state in which a current collection network is seam resistance welded to the inner circumferential surface of a negative electrode can by the method of the present invention. Figure 1 is a perspective view thereof, and Figure 2 is a perspective view thereof. FIG. Figure 3 shows a state in which a current collecting network is crimped onto the negative electrode can, and then lithium is crimped onto the inner peripheral surface of the negative electrode can through the current collecting network, and Figure 4 shows a cylindrical shape manufactured by the method of the present invention. It is a ¥41+ cross-sectional view showing a lithium alloy. 1. Negative electrode can, 2. Current collection network, 3. Lithium,
21, 22...Roller electrode distance 1 figure left 2 figure 3 figure 7 t4 figure

Claims (1)

[Claims] (1) A current collection network is welded to the inner circumferential surface of a bottomed cylindrical negative electrode can,
In manufacturing a cylindrical lithium battery in which lithium is brought into close contact with the inner peripheral surface of the negative electrode can through the current collecting network, a pair of roller electrodes is used to weld the current collecting network to the inner peripheral surface of the negative electrode can, and one roller electrode is welded to the inner peripheral surface of the negative electrode can. The current collecting network is placed in the negative electrode can, the other roller electrode is placed on the outer peripheral surface of the negative electrode can, and the current collecting network is seam resistance welded to the inner peripheral surface of the negative electrode can without rotating the negative electrode can or the roller electrode. A method for manufacturing a cylindrical lithium battery.