Hi all,
The cable has become disconnected, can I somehow fix it as the rest of the battery are good. I tried to solder it (that's why it looks a little burned ) but the soldering lead refuses to stick to the battery part (what looks like aluminum foil).

Replace the battery, every time you touch that with your soldering iron you're risking igniting it in your face.

The tabs are from Aluminum, no way to re-solder them with normal solder.

You're better off throwing it away before it explodes.

That tab was made to be longer than it is. So the heat of soldering the wire on wouldn't get to the cell. Now you want to solder a lot closer to the actual cell and try to get the right solder without over heating the cell, which is pretty likely to happen.

Plus its a cheap pack made of low quality cells that fail easier than more expensive packs. Is it really worth it if it burns down in the truck next month (or week) and its junk? Or worse possibly.

Its an inexpensive battery. Play around with it if you want, but don't count on it and make sure it cant make an expensive problem.

As you already found out, it’s nearly impossible with regular solder. I had this same dilemma a couple months ago and asked at my local hobby shop, luckily the guy next to me explained I needed flux that works on aluminum. Right at the hobby shop he pulled out his phone and pulled up what I needed on eBay and claimed it worked great. Its a Russian brand. I was doubtful but it works great! Doesn’t take much heat. I don’t know how to post the eBay link but if you pm me I’ll try and send it to you or you can search “Flux for low-temperature soldering of aluminum.Made in Russia. It has a blue label. I tore an aluminum can and did a couple quick test to get used to it but it’s a low temp flux so you don’t have to worry about putting a bunch of heat into a lipo

Flux won't lower the melting point of the solder, it just cleans the surface and helps the solder flow after it melts. You'll still need to apply heat.

I am pretty sure tabs like that need to be spot welded, not soldered.

They do come spot welded but the aluminum tab they generally spot weld to the tab to be soldered it torn


Here I tore off the tab that is used for spot welding and tore the aluminum tab leaving just a little to resemble how his, and the part that’s hard to solder


Here is the flux that was recommended to me and works well





I am in no way advocating anyone doing this and of course it would be best to just buy a new pack. Rather than cutting open some of the other packs Ive refurbished like this Just spent a few minutes on a battery ready for the recycle bin to show it is possible and I use packs like this in job site radios etc.

If you do resolder, make sure you save the little foam pieces, or at least tape and isolate the tabs