Wireless Charging

Inductive charging (also known as "wireless charging") uses an electromagnetic field to transfer energy between two objects. This is usually done with a charging station. Energy is sent through an inductive coupling to an electrical device, which can then use that energy to charge batteries or run the device.

Induction chargers use an induction coil to create an alternating electromagnetic field from within a charging base station, and a second induction coil in the portable device takes power from the electromagnetic field and converts it into electrical current to charge the battery. The two induction coils in proximity combine to form an electrical transformer. Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling. Recent improvements to this resonant system include using a movable transmission coil i.e. mounted on an elevating platform or arm, and the use of advanced materials for the receiver coil made of silver plated copper or sometimes aluminum to minimize weight and decrease resistance due to the skin effect.

Advantages

• Protected connections – no corrosion when the electronics are all enclosed, away from water or oxygen in the atmosphere.

• Safer for medical implants – for embedded medical devices, allows recharging/powering through the skin rather than having wires penetrate the skin, which would increase the risk of infection.

• Durability – Without the need to constantly plug and unplug the device, there is significantly less wear and tear on the socket of the device and the attaching cable.

• No e-waste

• Non-radiative energy transfer

Disadvantages

• Lower efficiency, waste heat – The main disadvantages of inductive charging are its lower efficiency and increased resistive heating in comparison to direct contact. Implementations using lower frequencies or older drive technologies charge more slowly and generate heat within most portable electronics.

• Slower charging – due to the lower efficiency, devices can take longer to charge when supplied power is the same amount.

• More expensive – Inductive charging also requires drive electronics and coils in both device and charger, increasing the complexity and cost of manufacturing.