Wireless Charging Appears Ready for Prime Time
Sixto Ortiz Jr.
APR 12, 2013 08:54 AM
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Wireless technology has offered convenience for people who use smartphones, laptops, and other mobile devices except in one area: charging batteries. For this task, users still generally must have a charger and be near an electrical outlet.

Now, though, even this activity appears ready to go mobile.

A number of organizations are working on wireless-charging technologies and hope to roll them out this year. Some even promise to let users charge devices on specially equipped everyday objects such as tabletops.

Earlier wireless-charging approaches proved cumbersome, expensive, unattractive, or just unpopular. However, proponents say, that's about to change.

As with most young technologies, there are competing approaches, so it could take time to adopt one or two standards that will work with most devices.

Driving Forces

Convenience is a key factor behind the push for wireless charging, which could eliminate the need for users to carry multiple chargers for their different devices, noted Wesley Dean, research analyst for energy and power systems for Frost & Sullivan, a market-research firm.

This has become increasingly important because battery storage has not kept up with smartphones' growing power demand, causing the devices to need charging more often, explained Jason DePreaux, principal analyst for emerging power technologies at IMS Research.

Charging Goes Mobile

Even though wireless charging is only now becoming important, the principal technology behind it has been around for a bit more than 100 years. Back then, Nikola Tesla demonstrated the use of resonators to inductively transfer electricity from a source to a device needing power, said David Baarman, director of advanced technologies for Fulton Innovation, which developed eCoupled wireless-charging technology.

Some approaches have delivered wireless charging but only, for example, via special cases or covers for devices.

However, said IMS Research's DePreaux, consumers didn't widely adopt these approaches because they didn't want to have to spend more money on phone-mounted devices to enable wireless charging.

In addition, accessories such as cases could make a product less attractive or interfere with its operations, explained Wireless Power Consortium (WPC) chair Menno Treffers, who is also Philips Electronics' senior director of standardization.

A Close Look

According to Frost & Sullivan's Dean, magnetic inductive charging is the secret sauce behind wireless charging.

This approach uses induction coils to establish an electromagnetic field — which enables power transmission — between transferring and receiving devices.

The sending device creates an electromagnetic field at a frequency that resonates with a coil in the receiving device.

The device being charged then uses its coil to convert the electromagnetic field back to usable power.

Dueling Approaches

Four primary wireless-charging approaches exist for mobile devices.

The WPC's Qi. The WPC — an international industry group with about 140 members—is promoting the Qi (pronounced "chee") wireless-charging standard. Members include France Telecom, Fulton Innovation, HTC, Huawei Technologies, LG Electronics, Motorola Mobility, NEC, Nokia, Panasonic, Philips Electronics, Ricoh, Samsung Electronics, Sony, Texas Instruments, Toshiba, and Verizon Wireless.

Qi uses resonant magnetic induction to cause electricity to travel via magnetic fields between a power-supply coil and a receiving coil.

The process starts when a user places a mobile device on the charging station, explained Fulton's Baarman.

Both transmitter and receiver have communications units that use signals in a format defined by the Qi specification.

The process includes a ping phase in which the base station looks for a compatible device. In the identification and configuration phase, the station identifies and authenticates the power receiver. The station then collects the receiver's configuration information, determines it uses the same charging protocol, establishes its needs, and transfers the correct amount of power.

Three phones sold in the US work with existing Qi charging stations: the Nokia Lumia 920, the Windows Phone 8, and the Google Nexus 4.

Several other phones could work with the Qi standard but don't yet come from the factory with all of the necessary functionality.

Power Matters Alliance's Power2.0. Proctor & Gamble and Powermat Technologies, which develops wireless energy-transfer products, established the PMA in March 2012 to develop a group of standards, called Power 2.0, that enable advanced wireless charging via magnetic induction.

The PMA's Smart Wireless Power Technical Working Group has developed two smartphone specifications.

One addresses the physical and logical interfaces for a wireless charging card that could be inserted—and perhaps eventually embedded—in smartphones.

The other specifications define the PMA protocol, which lets users charge wireless devices at compatible charging stations located in restaurants, stores, and other places.

AT&T, Google, and Starbucks — which could include charging stations in its many shops — are PMA members. The only Power 2.0 products available are Powermat's own line of accessories and chargers. So far, no product certification program is in place.

Alliance for Wireless Power. In May 2012, Qualcomm, Samsung, Ever Win International, Gill Industries, Peiker Acustic, Powermat Technologies, and SK Telecom formed the A4WP.

On 2 January 2013, this consortium of global wireless-power and mobile-industry companies approved a specification for a technology that simultaneously charges multiple devices.

The A4WP is now working on branding and certification for its technology, which has a simple transmitter-antenna design and power-control system.

It also enables the transfer of power through nonmetallic surfaces, which provides greater flexibility in building transmitting stations than other approaches allow.

In addition, A4WP's technology would reduce complexity by enabling longer-distance power transfer without multicoil repeaters.

A4WP president Kamil A. Grajski, who is also Qualcomm's vice president of engineering, said his organization's technology would enable inductive charging even when the magnetic coupling is weak.

This would let users perform wireless charging without having to worry about either precise positioning of the mobile device or direct contact between device and charger, he explained.

Companies could thus incorporate wireless-charging surfaces into unconventional settings such as furniture or vehicles.

Intel's Wireless Charging Technology. The chipmaker's WCT will turn a notebook computer into a charging station using internal resonance charging. Users launch an application on their laptop and then place their smartphone within an inch of it.

Proponents say vendors will release Intel-chip-based ultrabook computers and smartphones with WCT capabilities in the second half of this year.

Charging Challenges

Wireless charging faces numerous challenges.

According to Vishal Sapru, Frost & Sullivan's power supplies and batteries research manager, wireless charging is less efficient and thus slower than wired approaches.

Also, the longer charging period can overheat batteries and shorten their lives.

And if users charge multiple devices near one another, the various magnetic fields might generate interference, making the charging process even less efficient.

Because of all of these factors, wireless charging won't replace wired charging but instead will help users when the latter isn't possible, said Ifi Majid, Nokia's North American head of product marketing for smart devices.

Meanwhile, the number of proposed wireless-charging technologies could delay the adoption of a single standard, as well as confuse both consumers and device manufacturers.

Charging Forward

For wireless power transfer to succeed, public charging stations will have to be available.

When Nokia unveiled its new Lumia smartphones, which users can charge wirelessly, it announced one partnership with Virgin Atlantic to set up stations at airport lounges and another with Coffee Bean & Tea Leaf to have them in their coffee houses.

IMS's DePreaux said that the development of longer-lasting device batteries — something not foreseen for the near future — would greatly undercut wireless power's marketplace momentum.

For now, though, he noted, the nascent market is small but growing fairly rapidly, with several million mobile devices with integrated wireless-charging capabilities shipping this year. However, he added, this is still a small fraction of the 1 billion smartphones in use today.

By 2020, though, the market for wireless power for mobile devices will surpass $5 billion annually, according to Pike Research.

"The barriers to adoption for wireless power are lifting, and it's clear that this is an environmentally friendly set of technologies that, before the end of the decade, could contribute to a significant reduction in carbon emissions and energy used to produce, ship, and dispose of conventional charging equipment," said Pike research director Eric Woods. "Wireless power will become a ubiquitous form of charging in many applications."

Sixto Ortiz Jr.

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