On January 30, Xiaomi launched the air separation charging technology for the mobile terminal. The mobile phone does not need to be placed on the charging board. It can be charged when playing games and brushing web pages in bed.

Motorola also demonstrated its space charging technology more than an hour before Xiaomi early this morning. Its charging transmitter is more compact.

When the iPhone X was just released in 2017, the wireless charging power of the mobile phone was only 7.5W. Just over three years later, Xiaomi pushed the wireless charging power of the mobile phone to 80W last October.

At present, the wireless charging power produced by Huawei and oppo is about 40W, and that of Xiaomi is 50W. After the wireless charging power reaches the wired charging level, the “true wireless” charging method of space charging may become the next technical breakthrough.

In fact, the principle of wireless charging technology was first proved feasible in the MIT Laboratory in 2007. Researchers used copper coils as electromagnetic resonators to realize wireless power transmission.

However, it was not until 10 years later that Apple commercialized the technology on a large scale. It can be seen that the wireless charging technology is difficult to achieve commercial mass production. The concept of space charging has been put forward for seven to eight years.

Why are Motorola and Xiaomi releasing the space charging technology one after another today? What are the technical problems behind the application of space charging technology and mobile phones that need to be broken through? What are the “old guns” in the space charging field? Will the space charging technology become the next milestone in the wireless charging industry?

01. radio frequency technology is the future, “high efficiency and accurate charging” is the key

In fact, wireless charging technology is mainly divided into three categories: electromagnetic induction technology, electromagnetic resonance technology and radio frequency technology.

At present, the most common wireless charging technology used by apple, Samsung, huami OV and other manufacturers is electromagnetic induction technology, which mainly converts and transmits energy through electromagnetic coils.

For example, all kinds of wireless charging boards and wireless charging bases use this technology, and the Qi standard we are familiar with is based on this technology.

Of course, the development of electromagnetic induction technology has been relatively mature. One of its biggest features is that it has high charging efficiency, and the conversion rate is usually about 80%. Its disadvantages are also obvious, that is, the mobile phone must be close to the charging board, and the free charging distance is almost zero.

Electromagnetic resonance technology is slightly further than electromagnetic induction in terms of charging distance. It can allow wireless charging of about 10cm, but the charging efficiency is relatively low, and the conversion rate is about 70%.

At present, there are some charging boards in the market, which allow users to be fixed at the bottom of their desks, and their mobile phones can be charged when they are placed on the desktop. They use electromagnetic resonance technology.

Now we see that the space charging technology released by Xiaomi is a kind of wireless RF technology. The principle of this technology is to use the space electric field as the medium for energy transmission. In this way, there can be a significant breakthrough in the charging distance and the charging method can become more flexible.

Xiaomi’s wireless charging system consists of 144 antennas, which can transmit energy to the mobile phone in the form of millimeter wave extremely narrow beam, and the mobile phone terminal receives it through the micro beacon antenna. It can realize long-distance wireless charging with a power of 5W within a radius of several meters.

In Motorola’s space charging scheme, the transmitter is smaller, about the same size as the common wireless charging base, and can charge multiple devices at the same time. However, Motorola did not disclose the specific power of its space charging scheme.

In fact, the two wireless charging technologies of electromagnetic induction and electromagnetic resonance are not “truly wireless” and still need to keep the equipment close to the charging base. Wireless RF technology will undoubtedly become the main technology implementation path to break through this limitation in the future.

Of course, the problem of space charging is also obvious, that is, the charging efficiency is relatively low. In the choice of wireless charging technology route, there is a sense that “you can’t have both fish and bear’s paws”.

However, due to the fast power consumption and large battery capacity of mobile phones, the most critical factor that has the greatest impact on the experience must be the charging speed. The charging speed is determined by the power, and the low charging efficiency has undoubtedly become one of the main obstacles between the space charging and the mobile phones.

In addition, another challenge of charging the mobile phone is that the mobile phone may be constantly moving, so accurate positioning of the mobile phone becomes very critical. More accurate positioning can also significantly improve the charging efficiency and avoid energy waste.

In the in-depth communication between the reporter and wangyanteng, engineer of Xiaomi fast charging team, he agreed that the technologies related to the frequency and power of the space charging transmitter and the technologies related to the accurate positioning of the charged equipment are two very important points.

However, he said in particular that these two points are important, but there are many sub items, each of which is full of technical challenges.

02. millimeter wave can also be used for charging. Most of the “big guys” in the industry are still American and Japanese enterprises

As a way of wireless charging, wireless RF technology also has an obvious advantage that it can use a wide variety of RF types, including millimeter wave, centimeter wave, infrared, Bluetooth and even WiFi.

Therefore, it also provides convenience for enterprises in the industry to choose different technical routes and differentiated competition.

In the field of space charging, American enterprises started relatively early, such as ossia and energy, which have a development history of more than 10 years.

Ossia still appears frequently in the public eye. They were founded in the United States in 2008 and put forward the concept of wireless charging as early as the end of 2013. Three years later, they showed their own space charging scheme for the first time – the wireless charging base station COTA.

COTA is in a barrel shape and large in size. It is said that the device can be directionally charged within a range of about 3 meters. Ossia also specially designed a battery for this charging system, which can be charged across the air, which is very friendly to all kinds of remote controls in home life.

COTA uses the centimeter wave technology. The initial frequency is about 2.4GHz, which is very close to the frequency of WiFi. Therefore, the mobile phone does not need to add much hardware to realize COTA charging across the air.

This cm wave space charging process is similar to “pairing”, which is similar to Bluetooth or WiFi pairing. After receiving the signal from COTA, the mobile phone will send it in reverse to COTA, so that COTA can confirm its position, establish a transmission path, and then transmit energy.

However, the power of this COTA space charging is only about 1W, and the actual utilization value is not high. It is only displayed as a concept product.

It is worth mentioning that foreign media reported that ossia had cooperated with Wal Mart in a pilot project to charge electronic labels on about 1000 shelves through a COTA transmitter embedded in the ceiling of the supermarket.

This idea is very creative, from which we can see that the technology at that time only had certain use value for such products with low battery capacity, low power consumption and low charging demand.

When it comes to wireless charging technology, American energy is an unavoidable giant. It was founded in 2010. Five years after its establishment, it demonstrated its wattup wireless charging technology in 2015, which can charge multiple devices in the air within a range of about 4.6 meters.

Wattup uses the WiFi band, and the power of the transmitting device has certain advantages, about 10W.

It is worth mentioning that in 2017, energy entered into a partnership with dialog, an apple chip supplier, which said it would jointly develop ultra long-distance wireless charging technology. In 2019, they also entered into a cooperation with vivo, a domestic mobile phone manufacturer, to cooperate on wireless charging technology.

Now, two years later, vivo may have made a big move in the field of wireless charging technology.

Compared with the two established enterprises, guru, another young American start-up founded in 2017, boldly used millimeter wave technology. In 2020, they launched an isolated charging device, which looks like a “desk lamp”. When the mobile phone is placed under the lamp, it can be charged in an isolated space.

It is understood that guru uses the radio frequency lens technology to concentrate the radio into a beam and send it to the mobile phone and other equipment installed with the receiving unit through the air.

The radio frequency lens technology is said to be one of the key technologies in the field of space charging.

However, guru’s wireless charging desk lamp cannot charge the device when it is covered.

Compared with guru, the air separation charging scheme shown by Xiaomi today is more mature. It can not only realize the unobstructed charging, but also increase the charging power to about 5W.

5W power may not be enough in the current mobile phone industry, but don’t forget that most of the solutions launched by the first mover enterprises in the United States only have about 1w-2w charging power. One of the main reasons why they can’t be applied in the consumer electronics field on a large scale is that the charging efficiency is not available.

In addition, just a year ago, the standard charging plug of Apple iPhone was still 5V 1a, and the power was 5W. It can be said that the power of space charging has reached the level of early wired charging.

03. the large-scale implementation still needs to solve the cost problem, and the implementation of consumption concepts and standards is difficult

The centralized appearance of the two mobile phone manufacturers’ space charging technology today is actually the result of the long technical accumulation of the industry for more than ten years.

However, we can see that there are still many challenges in the large-scale commercial use of space charging in the consumer field, whether it is the concept product displayed or the small-scale commercial use at the to B end.

From the demonstration videos of Xiaomi and the cases of American enterprises, it is not difficult to see that the “space charging pile”, that is, the transmitting end equipment for space charging, is still relatively large, the process is relatively complex, and the RF materials used are also relatively expensive.

How to reduce the cost to a reasonable range and a range acceptable to consumers on the basis of taking into account the transmission power and frequency is still a big problem.

In addition, the power of the current demonstration scheme of space charging still needs to be further improved, and the search and positioning of equipment need to be more accurate, because the actual family living environment is very complex, which will further improve the requirements for positioning accuracy.

In addition to the technical problems, in fact, during the early development of the space charging, many questions about the technology were partly focused on whether it would have an impact on human health.

In the early years, many people even thought that mobile phone signals and WiFi signals would produce radiation to the body and affect health, but in fact, these radio waves were almost harmless to the human body.

For example, millimeter waves are different from α、γ and β X-ray, which will not produce chemical reaction to the irradiated object, and thus will not cause any DNA change to the object. At present, no experimental data show that millimeter wave radiation will have a negative impact on human health.

▲ non ionizing radiation and ionizing radiation

But even so, it takes time to educate the consumer market, and it is understandable that early users have some doubts about this location-based technology.

On the other hand, the implementation of technology is inseparable from the improvement of industry rules. Each country will also formulate relevant laws and regulations according to its own situation.

According to the current situation, even ossia and energy, which can be called veterans in the industry, have not obtained the technical certification of all frequency bands used by them by FCC in the United States.

China started late in the field of wireless charging technology, and there is still much room to catch up. There are also more areas to be filled and improved in the formulation of industrial laws and regulations.

With regard to the air separation charging technology launched by Xiaomi today, the reporter also had in-depth exchanges with people in the industry who are deeply invested in the charging head network. They generally believe that this technology presentation is more conceptual.

“The commercialization of the space charging technology in the smart phone field still needs to solve a series of problems, including safety, regulations, costs and so on. It is conservatively estimated that it will take several years,” an insider told reporters.

04. conclusion: wireless charging is hard to win, and self-developed technology can break the wrist

In the first three years of the development of mobile phone wireless charging, the charging power has been improved by leaps and bounds, from 7.5W to 80W, more than ten times. Since 2021, with the release of Xiaomi space charging technology, the way of wireless charging has undergone disruptive changes.

It seems that wireless charging can get rid of the shackles of cables for the first time and achieve “true wireless”. Of course, there are still many areas to be improved in terms of charging power, conversion rate, cost, safety, laws and regulations, and it will take some time before it is truly commercial.

However, it can be seen that from screen to fast charging, from photographing to chip, more and more mobile phone core technologies are moving from pure supply chain technology to the downstream of the industrial chain. More terminal manufacturers begin to pay more attention to mastering core technologies from the source and increase their own proportion of self-research.

There is no doubt that in the smart phone war in 2021, technology is still a hard currency at a time when the head effect is prominent and the brand effect is enhanced.
Editor ajx

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