The invention discloses a new energy automobile battery box, and belongs to the field of batteries. The new energy automobile battery box comprises two box bodies arranged side by side, wherein a connecting seat is arranged on the outer surface of each box body; the connecting seats and a connecting part are detachably connected; the connecting part is arranged on the exterior of the box bodies; the connecting part can displace in a horizontal direction; the interior of each box body is sealed in a vacuum state; and the connecting part is connected with an engine and a charging port separately. The new energy automobile battery box has a built-in backup battery and a charge-discharge determination strategy; batteries can be charged when the new energy automobile is parked temporarily and at nights, so that time conversion can be provided for automobile endurance; and however, a memory effect on the batteries is not caused, so that the new energy automobile battery box has the characteristic of prolonging the service life of the batteries.