Will this work?

[Upnorth]

I am building a 15s3p LifePO4 26650 pack.

I wanted to use something better than nickel strip.
The brass shim stock I have is “yellow brass”, I think. Likely not the best conductor but way better than nickel strip. The shim stock is .010” (.254mm) so it should be good.

The trouble is that I cannot get my KWeld to spot weld the brass. Even at 125joules, even when slotting the brass. What I find works well is cutting a window and spot welding a small square of nickel over it, then spot welding that nickel to the battery…..

Is this a sound plan? It seems to be working very well.
I am using 25joules on the 0.15mm nickel, on tests it tears off the battery and leaves a small tab of it on the battery, very similar to the power tool packs I harvested some 18650 cells fromView attachment 1

 

[Chalo]

My cursory research suggests that brass is 28% as electrically conductive as copper, versus 22% for pure nickel.

I think the bad welds you're getting by using brass probably add more resistance than the marginal improvement in material conductivity can offset.

 

[Upnorth]

Interesting…. If the resistance of the two are that close I would have thought that the brass would weld more like the nickel….

 

[Chalo]

Brass isn't a weldable material, generally speaking. The zinc boils out and disrupts the integrity of the joint. Industrially, it's joined by brazing with an alloy of at least 15% silver content.

 

[fatty]

As above, the advantages is not in the resistivity of the material, but rather the large CSA. Sculpt those same busbars from standard nickel sheet and spot weld directly to batteries, and you will have a winner.