It’s been over a century since Nikola Tesla first demonstrated wireless power transmission was theoretically possible, yet we still haven’t seen it become a reality for mainstream consumers. Everyone is still reaching for the charging cable on a daily basis. How long must we wait for a wireless solution?
In the last decade, there has been an explosion of battery-powered devices. Mobile phones have now surpassed the total number of PC’s in the world, and as devices get smaller and more specialized, we can only expect the number of these devices to grow exponentially. But despite all the advancements in mobile technology, batteries continue to be one of the major constraints in moving mobile innovation forward. There are many products today that allow users to charge devices “wirelessly” by placing them on a charging mat, but that still requires the user to leave the device in a certain location for a period of time while it charges. True wireless charging, where the user can freely continue to move about and use the device while it is charging, will be a key technology as gadgets make the next leap of innovation.
Wireless Power transmission is hard. Currently, the solutions fall into two different categories–near field (or nonradiative) and far field (or radiative). Near field is the most prevalent wireless charging technique, mostly seen in the various charging pads that are currently available. Near-field charging works through various types of coupling methods, where the power transmitted dissipates exponentially as you move away from the transmitter, meaning you can really only get a few centimeters away at best.
Far-field techniques on the other hand, potentially offer true mobile, wireless power transmission. Unfortunately, they’re also more difficult to control. Far-field transmission requires the transmitter to send focused energy packets in the direction of a receiver, taking into account the various reflective properties we already see with wireless signals like bouncing off walls, furniture, etc. Far-field power transmission is typically done in two ways–lasers and microwaves. Laser technology is the more hazardous of the two, and is being used in more controlled environments for the time being. Microwaves show much more promise for mainstream wireless charging applications, and are already present in many consumer technologies.
WiTricity is probably the most well known company in this space, first demoing their capabilities by wirelessly powering a light bulb back in 2007. Since then, they have kept a relatively low profile, focusing on research and development. They are also a member of the Rezence alliance, a large consortium of tech companies attempting to standardize wireless charging. However, this technology is still based on near-field techniques, meaning this is limited to extreme short distances (less than 5 cm). This technology does show promise, such as being able to charge multiple devices with different amperages at the same time, but you can essentially think of it as charging pads 2.0. You still have to give up using your device by placing it on a surface while it needs to be charged.
Enter Energous, the darling of CES 2015. It was there, they unveiled a new product called WattUp, which takes aim at truly charging devices wireless with far-field techniques. The current iteration of the product can charge devices up to 15 feet away, meaning you can place the base station in a high traffic area like your living room or office, and have your devices charging simply by being in the room. At CES, an Energous representative told me they plan on integrating their transmitters into TV’s later this year, turning your living TV into a wireless charging hotspot. They also plan on selling a standalone transmitter by the end of the year, as well as a receiver/case to fit most smartphones, allowing you to retrofit any smartphone to wirelessly charge it. However, the end goal is to get the technology embedded directly into the smartphone as a first class citizen.
But is it safe? Energous is using the exact same 2.4 frequency that Wi-Fi uses today, which is less penetrative than existing cellular phone signals. Leveraging BLE, the transmitter and receiver negotiate when power is needed, and the transmitter beams small pockets of power in the direction necessary for the receiver to harvest it. Long story short, your devices charge and your body is safe.
It’s only a matter of time before Apple and Google push their way into this space, and it will be interesting to see how they choose to do it. Apple has already made several acquisitions of companies that they believed were way ahead in different areas of emerging tech, which have led to significant advantages for their platform, so it will be interesting to see if Google and Apple get into a bidding war for Energous. They could also be investing heavily internally and may have a solution of their own that is nearing primetime. Regardless, Energous’s splash at CES has demonstrated this technology is closer to reality than many may have expected, and I would not be surprised to see Apple or Google swoop in and buy them in 2015.
Although this technology is in its infancy, it doesn’t take much imagination to see where it can go in the next few years, potentially evolving into the infrastructure necessary to get us to an always on and connected mobile world. Wireless charging is also a key building block for wearables, allowing the devices to charge and be worn for extended periods of time without needing to be removed. This could also be big for things like smart clothing, where it may not be practical for a large battery to be attached to it. If the technology today can exist over WiFi, the coming years should usher in the ability to deliver this functionality over cellular type range as well, allowing us to truly break free from the charging cable. Within the decade, I believe we’ll look back in disbelief of the time when we had to consciously charge our devices.