Prisoners may find it difficult to make the commute and show up on time for a factory shift.

But actually yes, their labor contribution is a significant component in the supply chain.

For example, if an undocumented worker labors to produce food, that frees up another person's labor for working in a factory.

Some of the things used in the automotive industry that are made by prisoners:
-wiring harnesses
-interior components like seat covers, upholstery, and floor mats
-lighting components like headlights and interior lights
-repair and refurbishment of government fleet vehicles; brakes, body work, painting, mechanical repairs, etc..., which also frees up the labor of skilled mechanics to work on returning broken EVs to the road

Other goods and services produced by prisoners that indirectly assist the production of EV's include:
-circuit boards, mostly for government use, but lower demand for civilian circuit board manufacturing capacity lowers the prices of EV components
-office furniture
-eye-wear, including prescription lenses and safety glasses that might be worn in the EV factories
-metalworking, including making toolboxes, lockers and shelves that may be found in EV factories
-government warehouse & distribution jobs free up civilian labor that can go into EV supply chain logistics