Traditionally the 12V battery has been the electrical energy storage device used in passenger vehicles. The most common chemistry has been lead acid, however, as of 2020 we are seeing a move towards lithium iron phosphate.
12V System Voltage Limits
High level overview of the automotive based 12V system voltage limits.
Mastering 12V Lithium Iron Phosphate (LiFePO4) Batteries
Unravelling Benefits, Limitations, and Optimal Operating Voltage for Enhanced Energy Storage, by Christopher Autey