The invention relates to a
system and method for vehicle power supply. The
system comprises a
main battery, an auxiliary power source, an external charging interface, an energy conversion unit, a
control unit and a drive unit, wherein the
main battery is a storage battery; the external charging interface is connected with the power source to acquire
electric energy; the energy conversion unit is respectively connected with the
main battery, the auxiliary power source, the drive unit and the external charging interface; and the
control unit is used for controlling the main battery, the auxiliary power source, energy conversion unit and the drive unit, thereby realizing
energy management and
vehicle driving. The invention is characterized in that the auxiliary power source is an infrequently-used component, and is installed in the installation space of the auxiliary power source only when necessary; and when the auxiliary power source is installed, the
operation mode of the energy conversion unit comprises at least one of the following: a main battery independent
operation mode, an auxiliary power source independent
operation mode, and a main battery / auxiliary power source common operation mode.