A structure of a battery disconnection unit for an electric vehicle comprises a first high voltage relay switching to a position for supplying DC power supplied from the battery to the inverter or to a position for interrupting the supply of the corresponding DC power; a second high voltage relay switching to a position for supplying DC power supplied from the charger to the battery or to a position for interrupting the supply of the corresponding DC power; a PCB including a printed wired circuit electrically connected to the second high voltage relay and providing a DC power supply path between the charger and the battery; a substrate installed to support the first and second high voltage relays; and a metal bracket supporting the PCB and the substrate and operating as a heat sink radiating heat.