Wireless Charging Technology: Cutting the Cord for Mobile

Pierre Wattre
The Nokia Lumia is one of the first devices with wireless charging technology built-in.

What do radios, phones and the Internet have in common? All of them have been improved by cutting the cord. In 2013, the wires will slowly disappear with wireless charging technology.

The History of Wireless Charging Technology

The greatest geek who ever lived, aka Nikola Tesla, was the first man being able to send electricity wirelessly thanks to the “Tesla coils”. In 1899, Tesla managed to transmit 100 million volts of power over a distance of 26 miles, where it lit up a bank of 200 light bulbs and an electric motor.

The first attempt at wireless charging was by Nikola Tesla at Wardenclyffe Tower.

In 1901, Tesla built a laboratory and what will be call the Tesla tower in Wardenclyffe, New Jersey. It was an early wireless transmission tower intended for commercial trans-Atlantic wireless telephony, broadcasting, and proof-of-concept demonstrations of wireless power transmission. Unfortunately the tower was never fully operational, and because of funding shortage, the tower was demolished in 1917.

Since then, like many Tesla inventions, wireless electricity was a field in which research was not the priority, and has not improved for many years, because the focus was on wireless transmission of information, that has been done through radio waves and antennaes.

The Comeback of Wireless Charging

The Nokia Lumia is one of the first devices with wireless charging technology built-in.

Many people own the first widespread product using wireless charging without knowing it: yes, it’s electric toothbrushes. They use inductive coupling, which uses magnetic fields that are a natural part of current’s movement through wire. One coil is in the charging base, connected to the plug, the second coil is in the toothbrush, connected to the battery.

Besides electric toothbrushes, many applications exist where wireless charging can be applied, such as smartphones, tablets, laptops, and electric vehicles. Smartphones have been a strong driver for the market uptake of wireless charging products, as they consume way more energy than the mobile phones of the past decade, which led to many people having bad experiences with their smartphones.

However, in the early 2000s, many wireless chargers existed, using different frequencies, meaning that each model of device needed its own charger. To reach market uptake, there was a need for more standardization in the field of wireless power, which came in 2010 with the Wireless Power Consortium (WPC).

The Wireless Power Consortium

The Wireless Power Consortium (WPC) was started in 2009 to create a wireless charging standard called Qi. WPC specifies transmitter topologies and ensures backward compatibilities with existing WPC receiver products.

The Wireless Power Consortium had a large display at CES 2013, as their number of members has grown from 80 members to 140 in the past year. They displayed products from Nokia, LG, Samsung, and other members of the Consortium.

Some phones already include the Qi standard, such as Nokia Lumia 920, and others have to go through a little upgrade (change of back cover or sleeve needed) to be compatible with the Qi technology. The WPC announced in September 2012 that 8,5 million smartphones have shipped with wireless charging integrated as per its standard. 

Wireless Charging for Laptops and Tablets Is Coming Soon

 At CES 2013 in Las Vegas, a Texas Instruments device was on display that charged a tablet wirelessly, but it is currently not available in stores as the Qi standard for devices requiring more than 5W is not ready yet. According to members of the Wireless Power Consortium, the Qi standard for tablets and laptops should be available in 2013 (already in early Q2 for tablets).

More Wireless Charging

 The wireless charging mentioned before is the one that will know a market uptake in 2013 in many different products, but there are other wireless charging technologies besides inductive coupling, such as resonance, with standards defined by the Alliance for Wireless Power (A4WP) since 2012 (also partly used by some WPC products, the technology rely on two coils. The first one, when travelled by electricity, is resonating as a certain frequency, and receiver coils resonating at the same frequency will receive electricity from the transmitting coil) and long-distance wireless power (from space to earth for example).