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Wireless charging is expected to relieve the "mileage anxiety" of electric vehicles

Time: 2022.10.06

One of the biggest obstacles to the promotion of electric vehicles is charging, or the lack of charging infrastructure. There is a widespread "mileage anxiety" among car owners, who worry about running out of power and being trapped away from the electric vehicle charging station. But what if the car doesn't need a charging pile at all?

According to a report recently released by Nikkei Asia, the road using built-in wireless charging technology has been tested in Japan and may become a practical facility by 2025.

At the Research Center of Dalin Group, a Japanese construction company, electric vehicles can travel at a speed of 15 kilometers per hour on such roads. Uninterrupted electronic coils are buried under the road surface, and separate coils are also installed inside the electric vehicle, which can generate current in the coils of the vehicle by using magnetic field induction. The concrete used in the pavement is reinforced with fibers to increase durability. The 24/7 driverless bus will become one of the main beneficiaries of this breakthrough technology.

However, the report adds that the technology is still far from perfect. It points out that wireless charging is not as effective as using traditional cables due to transmission loss.

At present, not only in Japan, enterprises and institutions in many countries and regions have carried out research on wireless charging of electric vehicles, trying to fundamentally solve the problem of "mileage anxiety".

Ideas are not new

In fact, people have long been used to charging smart phones wirelessly. On September 20, Gizmodo, a well-known American technology blog, reported that the Wireless Charging Alliance, a global standardization organization promoting wireless charging technology, launched the first "wireless charging" standard QI in 2008. The first widely used mobile phone using the QI standard was the Nokia Lumia 920 in 2012.

This technology can be traced back to 1894, when Nicola Tesla, a science major, used resonant induction coupling to realize the wireless lighting of incandescent bulbs in New York City. Therefore, the idea of wireless power transmission is not new. Demonstration facilities have been installed or are under construction in many parts of the world.

In 2017, a 100 meter long section of the road in France was installed with wireless charging. When the car runs at a speed of 40 kilometers per hour on this "wireless road", it can be recharged for about 2 kilometers per kilometer. The speed of vehicles on this road can reach up to 100 kilometers per hour.

In 2018, a 2-kilometer long road in Sweden was installed with electric rails and charging facilities on the central axis. When a special device is installed on an electric vehicle, it will fall into the groove of the electric rail to charge the vehicle while driving. This is just like the track racing car we played when we were young. It's just that we replaced the toy car with a real car.

In 2020, Israel will install a wireless charging cable on a 600 meter long road. The technology is being tested. If all tests are successful, an 18 km bus lane will be built between the city and the airport.

In June this year, Italy built a 1.05km dedicated wireless charging road to demonstrate dynamic wireless power transmission. This road is equipped with electric wires in asphalt pavement, and vehicles can collect power through special receivers. When the car is traveling at the speed of 40 kilometers per hour, it can be charged at the speed of 1.5 kilometers per kilometer.

In 2023, Detroit, the United States, will put into use a 1.6 km long wireless charging road, which will be transformed. By then, cars with special receivers installed under the car will be able to drive and charge on the road.

How far is the future

Like many other emerging technologies that are gradually entering the mainstream market, vehicle wireless charging is not yet mature and still faces many technical problems that need to be overcome.

eetasia. Com reported that the positioning of wireless charging is not to completely replace wired charging, but to provide a convenient experience. This means that electric vehicles can use wireless charging mode in public places or outdoors, and can be directly charged without wiring after parking, and do not need to unplug the charging line when driving away; When used outdoors, it is safe to charge even under the conditions of snow, water and dust pollution.

According to the article, from the perspective of wireless charging technology for electric vehicles, the biggest R&D challenge is safety and mass production.

Wireless charging transmits power wirelessly. Even the low-power 5W wireless charging on mobile phones faces many security problems, including electromagnetic interference, heat generation, metal foreign matters, etc. The biggest security threat is metal foreign matters, which will absorb electromagnetic energy and generate heat violently, leading to disastrous consequences. The charging power of electric vehicles is 1000 times higher than that of mobile phones, and the threat of metal foreign matters will become more serious. In the system design, it is necessary to monitor whether there are threatening metal foreign objects between the two ends of the battery.

Problems with mass production include validation, reliability, and cost. The first problem encountered in large-scale commercial production is related regulatory certification. The wireless charging product itself is a powerful electromagnetic energy transmitter, which is difficult to pass relevant electromagnetic interference regulations; The coil in the system is a very unstable component, and its characteristics will change due to the interference of various factors such as production deviation and temperature. The system needs to overcome the coil factor through the adjustment mechanism to maintain its functional operation. The biggest problem in mass production is cost. At present, the cost of electric vehicle wireless charging system is very high.

According to the American media Auto World website, many participants, including Nissan, BMW and Renault, have been exploring wireless technology for many years. In fact, the BMW 530e inductive charging pilot project was rated as the green car technology of 2020 by Green Car Magazine. However, it has not "taken off" in any meaningful way. High cost and lack of standards are the stumbling blocks hindering the development of automobile wireless charging.

In general, in view of the hot trend of energy conservation and green energy development, wireless charging solutions for electric vehicles are expected to grow at a considerable rate in the next few years. With the continuous innovation of future transportation through disruptive technologies, it may soon become a thing of the past to worry about where to charge electric vehicles