Lithium ion batteries power electric vehicles. There are several different configurations (small cylindrical cells, pouch cells, prismatic cells). There are also several different chemistries (particularly for the cathode materials). Individual cells are combined together to create battery modules and groups of modules are combined to produce a battery pack. All together there could be several thousand individual battery cells in an EV’s pack. The voltage of a typical pack is in the 300-400 volt range. Lithium ion batteries require careful monitoring of the temperature and voltage of each cell and must be continuously balanced to avoid degraded performance and short pack life. The size of a pack is given by the number of kilowatt-hours (kWh) of energy that it can hold. A typical EV pack might hold 60-150 kWh. Some packs are air-cooled while others are liquid-cooled. Battery packs are extremely heavy (well over 1,000 pounds) and are often placed low, under the vehicle floor, to produce a low center of gravity to enhance handling performance. The bigger the pack, the further you can go.
(Image source: Jaguar)