SECONDARY BATTERY UNIT

A secondary battery unit arranged within a heat source unit that is internally provided with a heat source. The secondary battery unit comprises: a secondary battery; a heat transfer material layer which is arranged so as to contact the outer peripheral surface of the secondary battery; a heating device which is arranged to heat the secondary battery with the heat transfer material layer therebetween; a heat insulation material layer which is arranged on the outer peripheries of the heat transfer material layer and the heating device so as to face the heat source and which has a lower thermal conductivity and a shorter length than the heat transfer material layer; and a heat dissipation part which contacts the heat transfer material layer and an external heat dissipation part of the heat source unit and dissipates the heat from the secondary battery to the outside of the heat source unit.