Battery melt

Ive welded batteries on forklifts its very safe to do so only if the caps are off! Do not mess with a freshly charged battery with the caps on ever they will explode. Other then that they make steel molds that u may be able to reweld a threaded terminal on the good side the issue tho is number 1 did that melt actually make a hole? Battery junk. Next is finding the mold and parts and a solder stick by far and away ur cheaper replacing it. If it was a 1000$ cell with multiple interconnectors weld er up!

The procedure is literally using an oxyacetleyne torch and running it over all the open caps to insure no built up gas is present then set the mold warm up the lead then add filler