Novel welding method for anode tab and foamed nickel of battery

Abstract

The invention discloses a novel welding method for an anode tab and foamed nickel of a battery. A substrate of an anode plate is square plate-shaped foamed nickel. The method comprises the following steps that 1, the foamed nickel is fixed and leveled; 2, opening seams are formed in the end faces on the left side and the right side of the foamed nickel correspondingly; 3, first tabs are inserted into the opening seams, and the first tabs and the opening seams to be welded are welded; 4, the foamed nickel is prepressed horizontally; 5, first exposed ends of the first tabs are leveled; 6, second tabs are aligned and combined with the first tabs, and the first tabs and the second tabs to be welded are welded; and 7, the first exposed ends of the first tabs and the second tabs are wrapped with adhesive tapes. According to the technology, a mode that the first tabs are inserted into the end faces on the left side and the right side of the foamed nickel for spot welding is adopted, so that the surface and a three-dimensional space of the foamed nickel are maximized; the amount of adhesive powder of the foamed nickel is increased; the battery capacity is improved; the problem that the surface thickness of a positive plate is inconsistent is solved; and the battery performance is improved.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a welding method for a battery positive tab and nickel foam. Background technique [0002] At present, the matrix of the positive electrode of the battery is usually made of foamed nickel. Taking nickel-metal hydride batteries as an example, the normal process is: 1. Foamed nickel pressing groove (pattern printing); 2. Pre-pressing the thickness of foamed nickel; 3. Brushing powder; 4. . Tablet pressing; 5. Cutting; 6. Powder blowing; 7. Welding tabs; 8. Adhesive tape. This process is the current conventional practice, but this practice has some adverse effects: first, the foamed nickel substrate needs to be divided into a part of the area for welding tabs, this part of the area is called the tab welding area, this area is due to the use of Therefore, the traditional process needs to carry out the step of blowing powder after powder brushing, which is used to purge the additional active...

AI Technical Summary

Problems solved by technology

This process is the current conventional practice, but this practice has some adverse effects: first, the foamed nickel substrate needs to be divided into a part of the area for welding tabs, this part of the area is called the tab welding area, this area is due to the use of Therefore, the traditional process needs to carry out the step of blowing powder after powder brushing, which is used to purge the additional active substances attached to the tab welding area; secondly, due to the tab welding in the On the surface of foamed nickel, if the lugs are welded first, the paste powder cannot be evenly spread on the foamed nickel due to the protrusion of the tabs when brushing the powder. In the third aspect, the surface thickness of the entire pole piece will increase the thickness of the pole plate in this area by more than 0.2mm due to the adhesive tape on the pole piece, so that the overall plane thickness difference is ≥ 0.2mm, which corresponds to the uniformity of the polarity. The reaction and winding absolutely require the uniformity of the winding core and the full use of the foamed nickel material. There are flaws in the aspects; the fourth aspect, this process is divided into powdering and diversion in terms of function, that is, the surface of the foamed nickel is powdered, The tabs are responsible for diversion. In this process, the tabs are welded on the surface of the foamed nickel so that the two are intertwined and cannot be unified, which is detrimental to the consistency of the overall battery

[0003] In addition, due to the defects of this process, it is unfavorable to make high-power batteries or high-capacity batteries in actual production.

In the production of high-power batteries, under normal circumstances, even if the adhesive tape is attached, the area of ​​the exposed foamed nickel is ≥ n X 40mm2 (where n represents the number of tabs, and 40mm2 is the area of ​​the usual tab welding area). Foamed nickel will generate more heat during the reaction process, and in severe cases, it will burn out the entire electrode group, resulting in the scrapping of the battery

For the production of high-capacity batteries, first of all, the surface area and three-dimensional volume of the foamed nickel cannot be fully utilized. After deducting the share of this part of the volume, the battery capacity will lose at least 1%; Alignment, which increases the difficulty and tightness of winding; third, the deformation of the foamed nickel produced after spot welding the lug angle and pressing the cap will cause the plane thickness difference between the two to be ≥ 0.1mm, and problems such as winding cores will appear. Inconsistency, unevenness and other problems, which may cause short circuit or micro short circuit of the battery

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