Patent ID: 7915858

Claim:
A planar battery charging system, comprising: a primary power transmission side formed of an array of primary windings adapted to generate magnetic flux substantially perpendicular to a charging surface; and a secondary power receiving side comprising a secondary winding associated with a battery to be charged and being adapted to receive said magnetic flux when placed on said charging surface, said secondary winding being provided with electromagnetic shielding on the side of said winding opposite from the side to be placed on the charging surface; wherein the relative dimensions of the primary windings and the secondary winding are chosen to meet the conditions that (a) the area enclosed by the secondary winding is greater than the area enclosed by a primary winding, (b) the secondary winding or said shielding will always fully enclose a primary winding when a secondary winding is placed on said charging surface, and (c) a single primary winding generates sufficient power to charge a said battery.