Interestingly enough the “Clean Energy for America” bill pushes for additional tax incentives on EV's built by companies using union labor:

More specifically, the proposal says that electric vehicles assembled in the United States would qualify for a $10,000 tax credit while EVs that are built at facilities whose production workers are members of, or represented by, a labor union would be eligible for the full $12,500 credit.

It doesn't even make a lot of sense as an incentive to have workers unionize, since why would workers care what price what they're selling cars for. The law would only exist to benefit existing unions.