I m building a battery pack from used cells 32700 lfp. 16s10p. 

These r extracted from medical devices powertools scooters. etc. That company filed - n + side with a power tool. 

This cell shows 100 mOhms rusted place or 7mOhm sides depend on the probe place . How can fix it or should i spotweld  close to side. 

Thnx for help

29 minutes ago, occuplus said:

should i spotweld  close to side

If you spotweld, it should not matter whether you weld at the scratched portion or not, I'm pretty certain... if you have spare cells and time, spotweld a few together and measure the combined cell resistance, I would imagine that you will find, that since welding melts metal, the connection will be as good as welding to a non-scratched portion of the cell...

spotweld is the best option. the cells will rust further on the exposed scratched surface, the anti oxidation coating was removed.

I used to do the same, grind the spotweld leftovers off to make a smooth surface for future spotwelds, until I saw that the cells rust on the grinded areas and over time the rust spreads over the anode to form bumps under the cell wrapping.

I now salvage cells by grinding(dremel) the original spotwelds off between cells, trim the original spotweld to the desired shape, and spotweld nickel strips over the original spotweld.