The invisible revolution in wireless charging is underway

　　Wireless charging

　　In the first four months of this year, my country's new energy vehicle sales increased by 83% year-on-year, still maintaining a rapid development momentum. As electric vehicles continue to expand market penetration, the downstream industry chain is also actively seeking to change the charging scene through technological innovation. Wireless charging is one of the directions: allowing consumers to charge without piles, and even charge while driving.

　　Only by overcoming "bad" can we turn into "good"

　　It is reported that wireless charging of electric vehicles mainly uses electromagnetic induction or magnetic field resonance technology. A "receiving board" is installed on the vehicle chassis, and a "launching board" connected to the power grid is installed on the ground. Through the proximity of the two boards, the electromagnetic fields are coupled or resonate with each other in the near field. , to achieve power transmission. At present, wireless charging is mainly divided into two types: static and dynamic. Static wireless charging refers to charging when parking; dynamic wireless charging realizes charging while the vehicle is driving through a wireless charging system laid under the road. Wang Zhe said that the technology currently closest to mass production is static wireless charging. The charging efficiency can reach up to 95.4% (laboratory results) and the lowest is no less than 85%, which is basically comparable to wire charging; while dynamic wireless charging is expected to be 3~ Industrialization will be achieved in 5 years.

　　Wang Zhe believes that it is the future trend for electric vehicles to be equipped with wireless charging functions. For users, wireless charging only requires parking the vehicle directly into the parking space to charge. Wireless charging has no exposed high-voltage cables, which avoids safety hazards. Compared with wired charging, it is superior in safety and convenience. The China Electric Vehicle Hundreds Association also mentioned in the "Public Sector Charging Infrastructure Development Report (2019)" that wireless charging is an important means to solve the problem of charging electric vehicles in the driverless stage.

　　However, in actual operation, after the vehicle is parked in the parking space, it is required that the center of the receiving end coil on the vehicle and the ground transmitting end signal circle coincide with each other and the offset does not exceed 10cm (according to reports, Yougan Technology has increased this number to 20cm). The car owner can only charge wirelessly after reversing the car accurately and entering the designated location. In addition, if there are metal foreign objects in the energy path of wireless charging, it will cause heat and even risk of fire. Small metal objects such as paper clips and pins will affect charging. Therefore, the detection of metal foreign objects before achieving safe charging has become a core difficulty, and many companies are currently working on solving this problem.

　　Cost is another challenge. It is understood that Evatran, the leader in wireless charging in North America, provides rear-mounted wireless charging products for Tesla, BMW i3 and Nissan Leaf. The charging power is 3.6kW and 7.2kW, and the prices are US$6,000 and US$13,000. Wang Zhe mentioned that in terms of cost, if the shipment volume can reach more than 30,000 sets, the shipping price can be controlled within 10,000 yuan, and the cost reduction will be more conducive to the popularization of this technology. According to him, at present, if it is a low-power version of wireless charging products, the cost will increase by about several thousand yuan; if it is a high-power version, it will increase by 15,000 to 20,000 yuan; the main cost is at the transmitter, and the receiver only accounts for about 30 %.

　　Wang Zhe also clarified the issue of electromagnetic leakage that consumers are worried about: "The coupling coefficient of the device is relatively high, which means that almost all the emitted energy is received by the receiving end, and very little energy is radiated in the air. During the wireless charging process, There will be almost no impact if people are in or around the vehicle. We have done EMC testing (electromagnetic compatibility testing) for the whole vehicle, and the wireless charging energy field scattered into the space is not as large as the amount of radiation from a mobile phone placed to the ear. .”

　　The "undercurrent" after the "silence" continues

　　In fact, in 2014, ZTE New Energy signed relevant cooperation agreements with vehicle companies such as Beiqi Foton, Xiamen Kinglong, Yutong, Dongfeng, Shudu, and more than 20 cities across the country to provide wireless charging technology for buses. However, little news about the progress of the cooperation project appears in the newspapers. The reporter recently called an industry insider who had worked for ZTE New Energy and received a reply: ZTE New Energy's wireless charging project has been ongoing, but the specific details cannot be disclosed.

　　Previously, relevant people from ZTE New Energy have publicly stated: "At present, our wireless charging projects are concentrated in the field of passenger cars, and many car companies are actively seeking cooperation. Each car project will take three years, and the largest planning Will be released in 2020."

　　The latest report from Research and Markets shows that the electric vehicle wireless charging market is expected to reach US$407 million by 2025, with a compound annual growth rate of 117.56% from 2020 to 2025. In the global market, many companies are deploying wireless charging technology. Domestic companies include ZTE New Energy, Yougan Technology, Zhonghui Chuangzhi and other technology companies and scientific research institutes, and foreign companies include WiTricity, Evatran, Bombardier, Elix, etc. Currently, in addition to electric vehicle wireless charging system manufacturers who are increasing investment, some vehicle companies and component suppliers are also conducting independent or cooperative development. Wang Zhe’s point of view is: “Whoever can take the lead in mass production will influence industry standards and prompt more new energy vehicle companies to try this new technology.”

　　There are various signs that car companies intend to accelerate the marketization of wireless charging technology. It is understood that in 2016, Evatran developed the Plugless Power system for Tesla, allowing Model S owners to enjoy wireless charging services. In 2018, SAIC Roewe launched the Marvel The Porsche Taycan, which will be launched at the end of 2019, has a wireless charging equipment power of 11kW; the GAC Aion S, which was unveiled at the Shanghai Auto Show this year, also has a wireless charging equipment power of 11kW. At CES 2019, Honda exhibited its newly developed Wireless Vehicle-to-Grid wireless charging technology, which wirelessly connects electric vehicles to the power grid, allowing the vehicle to charge and discharge while parked on a pad.

　　Industrial development can only be achieved by setting standards

　　Internationally, wireless charging standards for electric vehicles are divided into two categories: First, the wireless power supply vehicle charging technical guide released by the International Society of Automated Engineers (SAE) in 2018 - SAE TIR J2954, which is a relatively recognized standard in the market. , putting wireless charging on the track of standardization; the second is the European standardization organization-IEC and ISO. IEC is responsible for the formulation of standards for ground vehicle segments, including ground equipment and wall-mounted equipment, and ISO formulates relevant vehicle-side wireless charging standards. It is understood that in China, the organization that sets standards for the vehicle end is China Automotive Technology and Research Center Co., Ltd., and the structure that sets standards for the ground end is the China Electricity Council.

　　"The threshold for wireless charging to be made into car-grade products is relatively high because it must comply with many test standards and meet hundreds of requirements. At present, the national standard for wireless charging has not yet been released." Wang Zhe said, "2020 In 2019, wireless charging products for electric vehicles are likely to be shipped in large quantities. It is expected that in the middle or late this year, my country's wireless charging standards for electric vehicles will form from a draft to a final version that can be released to the outside world. The introduction of the standard will promote the prosperity and development of the industry."

　　In January 2018, the National Standards Committee publicly solicited opinions on 365 proposed national standard projects, including "Special Requirements for Commercial Vehicle Applications of Electric Vehicle Wireless Charging Systems" and "Electric Vehicle Wireless Charging System Interoperability and Testing." The document points out that my country is an international leader in three aspects: electric vehicle wireless charging technology research, product development, and application promotion, but standardization lags behind, and it is necessary to achieve "standards to follow" as soon as possible. Our country has carried out standardization work on conductive charging and battery swapping of electric vehicles. Wireless charging, as the third way to provide energy to electric vehicles, has not yet been standardized in our country, which does not match our country's technological and industrial leadership. The wireless charging application of electric vehicles has special advantages, and standardization is a prerequisite for its promotion and development. Wireless charging systems can be used for unattended automatic charging of electric vehicles in garages, parking lots, charging stations and other places, greatly improving land use efficiency, building a new model for the construction and operation of public service facilities for electric vehicle charging, and accelerating the implementation of new energy vehicles in my country development strategy. For power companies, car companies, equipment manufacturers, operating companies, and users who have devoted themselves to the development and application of automotive wireless charging systems, the lack of standards has hindered the application and promotion of wireless charging technology in the field of electric vehicles.

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