400-Volt Architecture
400-volt architecture, also called a 400V system, is an approximate voltage class for an EV's high-voltage electrical system. It does not mean that the battery remains at exactly 400 volts.
What the label means
The actual pack voltage depends on the number and arrangement of cells, their state of charge, temperature and electrical load. The class still helps describe the voltage range for which the battery, inverter, charging equipment and other high-voltage components are designed. See Nominal Cell and Pack Voltage for the distinction between a nominal label and operating voltage.
Charging power depends on both voltage and current, together with the limits of the charger, cable, vehicle and battery. A 400V label therefore does not establish peak charging power, average charging power or charging time by itself. Some vehicles can also adapt between a charger's voltage and the battery system rather than requiring both sides to use the same architecture.
For the pack structure behind the voltage class, see EV Battery Pack.