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I have collected about 50 18650 batteries, most new. I will be dropping comments as i go about my build process and learning. This about the strips that connect the batteries, shopping for a electrode welder not, looks like a 200 dollar expense to get something reasonable. China made so far, us made are crazy exensive.
bare copper corrodes, so its often plated with nickle.
plain copper bars cannot be welded to the nickle plated cells (or tabs)
so either nickle plated copper (best) or nickle strips (common) are used.if you were not welding them, copper can be used, but then you would want to coat it so it doesnt corrode.. some people do this with solder, or with a silver compound…. the silver coating is more common with larger EV bus bars, than smaller ebike packs.
When a Copper bus or strip is coated with Nickel then welded to an 18650 cell, is the Copper welded to the cell or just the Nickel coating? Maybe this should be better asked in the ultimate suppository for welding 18650 cells.
We know that Nickel oxidises a lot less than Copper ; almost no significant oxidation.
But if you heat up Copper past certain temperatures, I oxides crazy fast in contact with the oxygen from the air. And that resulting layer of copper-oxide is not good at conducting electricity.Gold, on the other hand, does not oxidise at all (it’s a very noble metal), so gold-plated connectors make for very reliable connection in Hi-Fi equipement.
The thing is gold is way too expensive. So the Nickel-plating of Copper is good enough 2 years ago
