The idea of wireless phone charging is tempting: to put your device on the table to quickly charge its battery while you eat lunch or wait for a plane, without having to carry a tangled charger or find an electrical outlet. Many phones today offer this feature, and wireless charging pads are starting to appear in airports and restaurants.
But calling current technology “wireless” is still a bit of an exaggeration. It is true that the phone is no longer tied with a cable, but the charging pad is still plugged into a power socket, and the phone must be placed on top of the charging pad precisely in a certain way. So this technology is ultimately not very different from using a power cable. But that appears to be changing with the birth of two new forms of technology, one that’s truly wireless and that allows the phone to absorb power on its own from a remote source. Another big boost may come from Apple, which, according to news reports, is likely to introduce wireless charging in upcoming iPhone releases. This could make the idea become mainstream, and the technology Apple chooses, whether it’s the current system or a newer version, can influence industry trends.
Cordless charging systems rely on inductive coupling technology, the same technology that has been used for decades to charge electric toothbrushes and robotic vacuums. A spool of wire in the charging dock generates a magnetic field that flows through a spool of wire inside the phone, generating alternating current that charges the battery. Since the two spools of transmitting and receiving wires must be in contact with each other at a distance of only a few millimeters, the phone must be positioned in a certain way on the charging dock. This process is not compatible with the efficient use of energy, and is relatively slow, as it takes three hours to charge the Samsung Galaxy 7 device.
But it appears that there is an advanced technology that will be faster and able to free users from charging platforms. This technology – called “resonant coupling”, an upgraded version of inductive coupling technology – has the same basic architecture but with the addition of a few wire spools and additional electronic circuits in both the charger and the phone. As Alex Grozen, chief executive of Waitricity, an MIT spin-off that markets resonant charging technology, says the extra components make the transmission spool more efficient and tune it to a magnetic field at a specific frequency. “Then something magical happens,” Grozen says. “All of a sudden, the transmitting and receiving spools of wire don’t have to be perfectly aligned, and they don’t have to be the same size.”
Now the charging pad can be more than a foot away from the phone, plus it can transmit power at the same speed as a physical wire and across hard surfaces. This means that the charger can be installed under a table, which makes it a great surface to charge multiple devices, and users can place phones anywhere on it. “You can give your phone a ‘mini-meal of energy’ throughout the day, and charge it a little bit from time to time,” Grozen says.”.
It now provides a Galaxy phone S6And a few other phones have the possibility of resonance charging. But the high rate of power transfer that this technology provides makes it useful for more than phones. At the Consumer Electronics Show in January in Las Vegas, Dell unveiled a Latitude tablet containing a resonant charging receiver made by WhiteCity. Grozen says they are currently collaborating with General Motors to develop a garage floor charger case, where an electric car driver can stop in order to automatically recharge the car. According to Grozen, this technology may become available in cars by 2018, and he adds that wireless charging will make things easier for self-driving cars as well. .
But resonant coupling still falls short of delivering enough for some. Startups Energos and Ossia are developing a different charging technology that can power devices across a room or even a home. This happens by sending energy on radio frequency waves, similar to the Internet signals broadcast by Wi-Fi base stations. These two companies have been promising long-life chargers for more than a year. Steve Reason, CEO of Energos, recently told The Verge.The Verge The company’s wireless transmitters that can charge devices from several feet away will hit the market in 2017.
Longer shipping distances may come with some sacrifice in return. One of the challenges to long-range charging is that, says Menno Trivers, president of the Wireless Power Consortium(WPC), a global organization of manufacturers that oversees the application of inductive and resonant charging standards – “so energy efficient, so costly, and electromagnetic emissions so high that these products may have difficulty obtaining regulatory approval.” Trivers thinks this technology could be more suitable for powering small devices, including hearing aids, activity trackers, thermostats and smoke detectors that need less than 1 watt of power.
But that doesn’t mean it can’t be used with phones. Indeed, says David Green, director of wireless energy research at IHS Markit, a UK market analytics firm, all three technologies could have a place in the future of wireless charging. High-energy inductive and resonant charging can recharge phones from short distances very quickly, while drops of energy from long-range radiofrequency transmission can keep batteries full.
Many in the industry are now watching Apple to see which technology it will choose for the iPhone. The company is already introducing inductive charging technology in smartwatches, so it may decide to adopt the same technology with phones. On the other hand, its recent move to join the Wireless Power Consortium may mean that iPhones will come with inductive or resonant charging technology. And in light of Energos’ recent deal with Apple’s chip supplier Dialog Semiconductor, Apple may also be on the way to using long-range wireless power transmission technology on its phones, according to technology website Venturebit. Meanwhile, Harlan Sur, an analyst at JPMorgan, believes that Apple may come up with a dedicated wireless charging platform made by Broadcom.
Whichever technology Apple chooses, its decision could push wireless charging technology to be an integral part of the industry’s trend. No one can predict what Apple CEO Tim Cook is up to, Grozen says, but “all indications are that something is in the pipeline.”