EV batteries remain mysterious or even suspect for many consumers, including people leery of buying used EVs due to battery-life concerns. Regulators also need to know what’s inside cells: The Inflation Reduction Act requires automakers to source a growing percentage of batteries and even minerals from North America to be eligible for up to $7,500 in consumer tax credits. If that’s not complicated enough, battery materials such as cobalt and nickel are being scrutinized to ensure they’re ethical...