Battery pack with lead-plates

Batteries 1 are housed in the external case 2 with electrodes 1A oriented opposite the inside surface of a heat radiating section 10 established on at least one of the opposing surfaces of the external case 2. The lead-plates 3 connected to the battery 1 electrodes 1A are thermally coupled to the inside surfaces of the heat radiating sections 10. The external case 2 is made of plastic and provided with inward protruding regions 12 on the inside surfaces of the heat radiating sections 10, and the inward protruding regions 12 make surface contact and thermally couple with the lead-plates 3. The heat radiating sections 10 have depressions 13 outside the inward protruding regions 12, and battery 1 heat is transferred from the lead-plates 3 to the heat radiating section 10 inward protruding regions 12 and radiated from the external case 2 to the outside.