So you can't do it therefore it is impossible and nobody can do it.I can repair or rebuild almost any automotive engine and many transmissions and diff but I cannot rebuild a battery pack which cost over 22K for that Audi part only. A brand new 2.0 gas engine for that car is less than half that, I can buy a brand new short block for under 3K for that car.
https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/battery/80a915100k/
You can pick and chose your vehicle for your "new short block $3000" so can I pick and chose a PHEV with cheap rebuildable battery? Clearly one can not replace any Audi engine for $3k. $3k would be a start paying labor costs. The topic is an Audi PHEV.