A wireless charging system for charging a chargeable electrical energy source of a heating device for aerosol-gene rating articles comprises: —a charging device (3) comprising a planar flat transmitter coil (30), configured to supply an alternating current (I) to the planar flat transmitter coil (30); —a wirelessly chargeable electrical energy source (4) of a heating device (2) for aerosol-generating articles, comprising an electrical energy storage (41) and a tubular receiver coil (40) connected to the electrical energy storage (41), wherein the tubular receiver coil (40) has a longitudinal axis (42) and is adapted to be arranged in a charging position relative to the planar flat transmitter coil (30), wherein in the charging position the longitudinal axis (42) of the tubular receiver coil (40) extends in a plane parallel to the planar flat transmitter coil (30) and in radial direction relative to the planar flat transmitter coil (30), and wherein the tubular receiver coil (40) is arranged to overlap at least a portion of the planar flat transmitter coil (30).