 A piece of 1950s technology has become a critical system in EVs and hybrid vehicles. The 12-volt lead-acid battery. That same box of energy that started engines and powered electrical accessories from the 1958 Boulevard Cruisers to the current internal combustion engines is getting a makeover. In the new electrified vehicles and those with self-driving capabilities, the 12-volt battery has a direct role in the vehicle's critical safety systems and reducing emissions in hybrid vehicles.