Battery terminal question

[Deanwvu]

Hello all,

I just built a microwave transformer spot welder. The specific purpose of the welder is to add terminals to the tiny tabs of the Nissan Leaf battery cells. (The original copper terminals were removed by a prior owner--don't ask me why--I have no idea)

So, I plan to spot weld on some copper tabs to which I can then wire the packs together in series.

What is the minimum gauge sheet copper I should use for this pack so I can pump about 40 amps through it. I doubt it will be 40 amp continuous, but I would like it to be able to handle it.

Should I be using another material? Perhaps nickel tabs, similar to the ones we use in power tool packs?

Any insight would be helpful! I don't want to ruin the batteries by adding too much heat to the pack as well, so I do not want the electrode terminals to be thicker than necessary...

Does anyone know how thick the original copper leads are on a new Leaf cell??

 

[dnmun]

why not just solder some copper wire onto the tabs? you will get better conduction from the tabs than spot welding. nickel has four times the resistance of copper.

just pretin the ends of the tabs and the copper wire and while the wire is still hot then put the wire onto the tab and reflow the solder between them and then hit the tab with the sponge to cool it fast.

 

[Deanwvu]

That would work on the negative tab. It is copper.


The positive tab is aluminum. I've had difficulties attempting to solder to aluminum. Any advice?