DKblock Open Source Custom 18650 Battery Packs

This type of building battery packs is certainly not for high current applications as we need.
It’s for low power stationary battery packs such as powerwalls. There are similar designs available/in use for powerwalls and even with low currents there are safety issues.
For high currents connections between individual cell(s) groups have to be as short and solid as possible: (spot)welded, no connectors and no electronics in between.