Patent ID: 8232764

Claim:
A power receiving device, comprising: a power receiving coil having a spiral coil; a rectifier rectifying an alternating voltage generated in the power receiving coil; a secondary battery to which a direct current voltage rectified in the rectifier is charged; and a magnetic foil arranged in at least one of a position between the spiral coil and the secondary battery, and a position between the spiral coil and the rectifier, wherein the magnetic foil comprises a body of a plurality of stacked magnetic alloy ribbons comprising an amorphous alloy or an iron-based microcrystal alloy, and each magnetic alloy ribbon has an average thickness in a range of 5 to 25 μm, wherein the magnetic foil has a μr′·t value in a range of 30000 or more and 1320000 or less, where the μr′ is a real component of relative permeability of the magnetic foil, t [μm] is a plate thickness of the magnetic foil which is a total thickness of the plurality of the stacked magnetic alloy ribbons, and the μr′·t value is a product of the real component μr′ of the relative permeability and the plate thickness t, and wherein a power receiving rate of the power receiving coil is 0.25 W/h or higher.