Xiaomi’s space charging matrix has arrived! Can wireless charging of cars still come？
When it comes to wireless charging, many partners will applaud this function. Whether you are driving or going to work, you can charge it by putting it on the charging panel, at least you don’t have to carry all kinds of wire harnesses with you, but wireless charging can’t be truly wireless, and you still need to be close to the charging version; In many cases, the Qi charging panel can degauss the anti-shake function and chips of some electronic products, so such charging is still considered by many users as a "chicken rib function".
But it’s 2021, and the charging technology should make a breakthrough. Can we really get rid of the bondage? Xiaomi took out the research and development results: air charging technology. This technology can realize wireless charging at any position within a radius of several meters around the charging pile. Even if the mobile phone is held in your hand or in your pocket, it can be continuously charged as long as it is within the range of the charging pile.
The charging of millet in the air is different from the charging panel with the size of a CD, and its volume is close to that of a charging receiver of an indoor air purifier. Inside, five phase interference antennas are used for the spatial positioning of mobile phones, and they are composed of 144 transmitting antennas. Millimeter waves are directionally transmitted to mobile phones through beamforming. Xiaomi’s space charging technology only supports 5 watts of power at most, which is quite different from traditional wireless charging which can only be charged on the charging board.
Similarly, with the popularization of a large number of new energy vehicles, the charging problem is still a problem that many new energy vehicle owners want to solve. Many charging platforms, complicated charging operations, gun jumping and charging failures are unavoidable problems in the charging process, which makes the wireless charging technology of automobiles more and more valued. Although the wireless charging has greatly improved the user’s non-inductive charging experience, there is still no technology to support its mass production. Next, let’s take a look at which car companies are developing wireless charging technology.
■ Car companies that take stock of wireless charging technology
Zhiji automobile
First of all, the first thing is the brand-new new force of making cars — — Zhiji Automobile, it can be said that a press conference of Zhiji Automobile challenged the battery cruising range again and the technical specifications of the industry for charging facilities. It not only has a long battery life of 1,000 kilometers, but also is equipped with the world’s first mass production equipment of 11KW high-power wireless charging equipment. Officially, its charging efficiency is almost the same as that of traditional plug-in charging equipment.
Moreover, the official stressed that "Zhiji automobile adopts the principle of electromagnetic induction, and this technology installs two coupling coils at the ground end and the vehicle end, and uses the magnetic field coupling between the two coils to realize the transmission of energy from the transmitting end to the receiving end. Through wireless charging technology, we can avoid the direct connection between on-board charger and the ground power supply "; It is worth noting how to solve the charging efficiency of 11 kW, battery temperature control technology and battery thermal runaway protection. However, judging from the time planning of Zhiji Auto’s new car, it will not be officially delivered until 2022, so Zhiji Auto handed over the wireless charging technology to time.
Qualcomm Halo wireless charging
For the brand Qualcomm, everyone is certainly familiar with it. Nearly 85% of Android mobile device terminals in China are using chips from Qualcomm Snapdragon series. But it is not only a global leader in semiconductor chips, but also a research and development company for technologies such as navigation, satellite and radio frequency interconnection. The car wireless charging technology it developed was first used in the FE electric formula contest a few years ago.
Its Qualcomm Halo wireless charging system is based on electromagnetic resonance for wireless charging. Moreover, it has a higher coupling coefficient in charging efficiency and reduces the system current, and the energy loss during charging is lower than that of the current in the traditional cable. At the same time, Qualcomm Halo can adjust the charging power according to the user’s demand, and its range can range from 6.6 kW to 20 kW, so there is no need to worry about the charging efficiency. When it is used in the FE electric formula contest, it is more convenient for the safety car to rescue in time, at least it is not necessary to charge and pull out the gun for something.
In addition, Qualcomm also conducted experiments with BMW i8 and BMW 530e iPerformance models; Among them, in 2018, the BMW 530e iPerformance became the first car in the world equipped with wireless charging function.
In addition to the two companies mentioned above, there are also automobile manufacturers such as Audi, BMW, Mercedes-Benz, Volvo and Toyota that are studying wireless charging technology for electric vehicles. However, there are not many institutions engaged in the research of this technology in the domestic market, mainly Huawei, ZTE New Energy, BYD, BAIC New Energy, Zhonghui Chuangzhi, Xinbian Technology, Sensible Technology and other enterprises, but there is no production model supporting wireless charging in the domestic market at present. If Zhiji Automobile can achieve mass production around 2022, it will naturally stand out among domestic automobile brands.
■ What is the principle of wireless charging?
Let’s talk about the difference between wireless charging and wireless charging before taking stock of wireless charging technology. "Remote charging" sounds quite high-end and "black technology", but it is actually a kind of wireless charging. From the perspective of usage, there are three categories of wireless charging at present: electromagnetic induction, radio frequency and electromagnetic resonance wireless charging..These technologies are suitable for short-range, medium-short-range and long-distance power transmission respectively.
The wireless charging methods such as mobile phones and headphones currently used by everyone are actually electromagnetic induction wireless charging, but the charging equipment must have a coil and can work normally when touched at a very close distance.
The charging technology released by Xiaomi is radio frequency wireless charging, which transmits wireless signals through the built-in antenna. After receiving the signals, the charging equipment will convert the wireless signals into electricity to realize charging. The working distance of wireless charging can reach several meters, which is why Xiaomi will release it as a key technology.
The last electromagnetic resonance wireless charging also needs a coil, but the working distance of this technology is longer; In terms of technical characteristics, electromagnetic resonance wireless charging solves the problems of touch charging, charging location and more charging equipment brought by electromagnetic induction, and it is more convenient to use among the three wireless charging in terms of use cost. At the same time, it is also one of the important directions for the research and development of getting off the bus.
■ What are the difficulties in wireless charging of automobiles?
Although we have listed the wireless charging technologies currently used in the market, there are still insurmountable obstacles to the charging technology, although it solves the problems of "non-inductive charging" experience of users and the space occupied by charging.
Slow charging efficiency
First of all, the wireless charging technology has not been commercialized. At present, the highest charging power of passenger cars is only 11 kilowatts, but its low charging efficiency is equivalent to traditional wired conduction charging, and the overall equipment cost will increase accordingly. The price of a wireless charging panel with several kilowatts is about 10,000 yuan, and its charging efficiency is equivalent to the AC slow charging pile attached by the manufacturer. From this point of view, under the same charging efficiency, there is no doubt that the requirements for space are almost the same as wired charging, which is no different from household charging piles.
At present, the output power of a small number of passenger car wireless charging systems exceeds 20 kW, but the power of most schemes is less than 10 kW. At the same time, in the process of wireless charging, the charging transmission efficiency is only 80% at the fastest, compared with the wired charging efficiency of 95%, wireless charging can only be regarded as an inefficient and low-energy charging method.
It is difficult to charge safely
The second point is that charging is safe and difficult. At present, the new energy market can be said to have just solved the problems of battery fire and battery spontaneous combustion at the industry level, but from the safety point of view, the primary safety problem of automobile wireless charging technology is the means of electromagnetic wave transmitting energy.
Compared with the problem of wireless charging and heating of mobile phones and headphones, whether the electromagnetic radiation of cars will harm human body requires not only specific demonstration on the technical level, but also the safety construction of users’ psychology. In this case, the single learning cost is enough for the whole industry to invest more manpower, material resources and financial resources. Moreover, the construction of wireless charging infrastructure is still a challenge. For the current automobile charging alliance, it is not difficult to build a wireless charging parking lot, but whether it can be popularized as a public resource and the application scenarios after popularization need to be faced.
Wireless charging specification!
Finally, wireless charging technology needs the final location — — National standard for wireless charging. New technologies need to be popularized, and standards must be unified first; At the beginning of 2020, the National Standardization Administration Committee issued the "Wireless Charging System for Electric Vehicles Part 1: General Requirements" (GB/T 38775.1). Wireless charging system for electric vehicles Part 2: Communication protocol between on-board charger and charging equipment (GB/T 38775.2) and other four national standards. Standardized technical requirements, performance requirements, functional requirements, test requirements and test methods, interoperability requirements and other requirements;
(Domestic R&D team for car wireless charging)
However, judging from the current development plan, most of the standards for wireless charging interconnection will be promulgated in 2020, and the standards for wireless charging facilities will be promulgated in 2022. Before that, it was a process of exploring and formulating standards, and it was not difficult to use it. According to the research period of new energy enterprises for batteries, this technology will be perfect at least in the next decade.
However, it is undeniable that a small number of enterprises that are at the forefront of science and technology have a lot of experience in the research of wireless charging technology. Although they have failed to achieve mass production, it is enough for more brand partners to see the advanced technology.
■ State Comments:
On the whole, as a promising technology, if it is put into commercial use in the future, I believe it will set off another wave. Just like when Apple’s mobile phone was extremely simplified, it abandoned the buttons. Some partners may think that developing a power exchange station in this way can save more time than developing wireless charging, but in essence, the progress of science and technology is a further upgrade of human laziness, from fast charging to overcharging, building a power exchange network to future wireless charging, from efficiency to "non-inductive experience". However, wireless charging is only an experience at present, and we can only wait for the progress of science and technology and look forward to the arrival of wireless charging in automobiles.