So, I've been waiting on a few different orders of pure nickel plate. Sadly, my main order of a 1 kg roll of high purity nickel is taking a long time... but I also ordered some pure nickel that is not just straight plate. Surprisingly, one of the cheapest sources came very quickly (took 9 days from when I ordered it, including weekends):
https://www.aliexpress.com/item/1M-18650-Lithium-Battery-Nickel-Strip-Li-ion-Batteries-nickel-plate-belt-tape-For-18650-Battery/32823318769.html
**EDIT*** good chance this is nickel plated steel.... will confirm shortly... but first test says it is NOT pure nickel
I figure this kind of configuration can reduce the number of welds you need per a battery, and should conduct better considering it's a solid piece. And for $1.50 a meter, shipped... pretty damn good price. And the speed in which I got it is pretty impressive for such a cheap item (given, aliexpress sellers are hit or miss, sometimes you get lucky, sometimes no so much when it comes to shipping speed, when using the cheap free shipping options). The only slight negative was that while I ordered 6 meters from them, they sent them as 6 individual meters, not 1 piece of 6 meters. But, that's not so bad... again, especially not at $1.5 a meter.
Anyway, I still need to test this nickel strip to confirm it is pure nickel, and not steel plated nickel (the price being as low as it is, I definitely wanna test it). Not sure the best way to do this... is scuffing the metal then placing it in a salt water solution for a few days the best way?
As I said, I ordered a number of different nickel strip products like this from different sellers. Waiting on some that is setup for batteries that are offset (ie. if you packed them tighter together, instead of lined up like this strip requires). I'll be posting my experience here (and testing each to confirm they are pure).