Nokia Lumia 920 comes with an amazing charging technology called the 'Qi Wireless Charging'. Qi which is pronounced as 'chee' means 'energy flow' in Chinese. This technology requires two devices for it to work. The first device is a base station that acts as the energy source and the other that acts as a energy receiver. Thus, both the devices are two planar coils that rely on magnetic induction theory for the energy flow. The distance between these coils need to be 5-40 mm.
Nokia teamed up with TDK to implement Qi Wireless charging in its Lumia x20 series devices. TDK is on the forefront of this technology and has recently
announced the development of a 0.57 mm thick receiving coil that can be implemented in mobile devices.
Now, Nokia Lumia 920 has the same coil at the back panel which aids in wireless charging. The base station can be bought separately and comes in various designs. Also, one of the requirement of this technology is that the base station needs to be a flat surface which is evident with the design of the charging accessories available for Nokia Lumia 920.
Image Courtesy: Google, TDK, Nokia