The invention provides a storage battery unit capable of promoting heat radiation of an auxiliary device arranged below a storage battery module and preventing heat energy from staying in the unit; the storage battery unit comprises the storage battery module (11) having a plurality of batteries, and a storage battery frame (14) keeping the storage battery module (11) relative to the vehicle frame members, wherein the storage battery unit is configured in a space below the vehicle luggage tank; the storage battery frame comprises a frame assemble body (20) configured above the storage battery module (11), a lower rigid body (30) arranged below the storage battery module (11), and a connecting member (40) connecting the frame assemble body (20) with the lower rigid body (30) made of metal; the bottom surface of the lower rigid body (30) is provided with a DC-DC converter (12).