/diy/ - Do It Yourself

Hello /ohm/, /g/ tourist here.
Thinking of making my own PCB's to house 200+ 18650/21700 cells for e-moto battery packs in 14p20s config.
I need to pull about 300A from the pack and my current way of doing it is spot welding nickel strips for the 12p, soldering thicker copper strips for the 20s, and shrink/kapton wrapping them up into packs and chucking them in a box
It's pretty tedious and labour intensive, I was thinking of making a PCB-box that I can just throw the cells in and spot weld them, but not sure if there's any PCB's capable of handling 300A in this config without ridiculous pricing.
I see some guys doing smaller packs with thick copper PCB's - 48v 50A kinda stuff, but nothing 100+ amps, not sure if it's even possible/feasible.
what you you guys think?