True wireless charging has been in development for many years, but it is closer than ever

The transition from plugging the cable into the smartphone to placing it on the wireless charging pad is small but convenient. There are no more disruptive connections. Putting the phone in a compatible coffee table or small room in a car to share a wireless network feels like living in the future.

But at home, the wireless charger still needs to be plugged into a wall outlet and using the phone on the charger is more difficult than connecting to a cable. It feels like we are still a long way from perfection.

This is where remote wireless charging comes into play-a technology that transfers energy safely enough to charge the battery of a smartphone or other device from the other end of the room. In the future, when we sit in a bar or restaurant, take a nap on an airplane or stroll in a shopping mall, our smartphones will be constantly charged and automatically connect to charging stations, just like connecting Wi-Fi routers and 5G to the mast of today.

As early as 2018, we wrote about this future potential for the first time, when many companies were studying ways to adopt the Qi (pronounced chee) wireless charging standard and turn it into truly wireless.

A year later, in early 2019, a new alliance between Wi-Charge, Alarm.com, and Allegion promised to use remote wireless charging to power smart home devices such as door locks, motion sensors, alarms, security cameras, and smoke alarms. With this technology, many smart home products can obtain constant power without the need for wall outlets or battery packs.

The Israeli company Wi-Charge was established in 2012 and is still researching this technology, and has won innovation awards at the CES technology exhibition in 2018, 2019 and 2021. It uses a focused beam of invisible infrared light from a transmitter (installed on the ceiling of a room, for example) to a receiver embedded in the aforementioned device. Then use micro-photovoltaic cells to convert infrared light into electrical energy.

Designed to power low-energy devices such as sensors and door locks, the transmission power is less than 10 watts, so it is not suitable for smartphones and other more power-hungry products.

However, although this is a solution for home remote wireless power supply, the other three technology companies also hope to power smart phones in this way. The first to showcase its technology was the Chinese company Xiaomi, which released the Mi Air Charge system in January 2021. This also uses the base station to transmit power, this time using an "extremely narrow millimeter-wide beam," which is said to be able to charge a mobile phone about 5W.

This is at the low end expected by today's wireless charging boards, but if power is continuously fed into the smartphone battery, then high speed is not that important. The base station contains 144 antennas, which can send "several meters" of energy through the air and charge multiple devices such as smartphones at the same time. Xiaomi stated that this is “not science fiction,” but did not specify when it plans to sell the technology to the public.

In the same week, Motorola also announced remote wireless charging technology. Here, a pair of smart phones can be charged 100 cm from the charger itself. The technology is based on the Qi standard; Motorola also stated that it can charge up to seven mobile phones at a time, but did not specify their battery charging speed.

Like Xiaomi, Motorola did not give any indication of when this technology will be commercially available, but it must be a positive thing to see that it is under development.

Recently, in late February 2021, we have the Chinese company Oppo, which demonstrated another remote wireless charging technology. The demonstration comes from a 30-second video showing a concept phone with a scrollable screen that can be charged from a distance; Oppo refers to this technology as wireless air charging.

Xiaomi’s demonstration seems to show that power is transmitted wirelessly from the base station to the mobile phone on the other side of the room, but now it seems that Oppo’s system has a low degree of freedom. A video shows how to fix the phone directly above the charging pad. Although it is slightly tilted to different angles, the user carefully places it in a place above the charger.

These technologies are likely to be improved in the next few months and years, but it seems doubtful whether any technology can be commercialized within a period of time, certainly not this year.

But for now, we are very happy to see that many companies are committed to developing solutions that will one day bring true wireless power to our mobile phones, smart watches, smart home devices and other products.