Special planning ｜ RTS life-and-death quality assurance and safety of power exchange
In the investigation of power exchange, we can see that among the options that think the biggest problem of power exchange is what, 36.95% people choose the quality assurance problem as the most concerned issue. During the investigation and interview, it is generally believed that the battery replaced by your own car will be an old battery or a battery with signs of attenuation. It will affect the cruising range or cause vehicle damage. On the issues of quality assurance and power exchange safety, this paper makes an all-round analysis in the chapter of quality assurance and power exchange safety in "RTS for Power Exchange" specially planned by Sina Automobile.
The state has issued relevant testing and construction standards for batteries, charging piles and stations of new energy vehicles.
The national testing standards for new energy electric vehicles include complete vehicles, parts, interfaces and facilities. The power batteries of new energy electric vehicles belong to the category of spare parts. For the testing of power batteries for new energy electric vehicles, the General Administration of Quality Supervision, Inspection and Quarantine of China and the National Standardization Administration of China jointly issued six national standards on May 15th, 2015, which were fully implemented in 2016.
There is no clear policy on the specific index range of battery quality assurance and attenuation. The battery core, connection board and circuit board are basically agreed according to the warranty of the car company. For example, BYD is a lifetime battery warranty; Roewe guarantees the battery attenuation; Beiqi New Energy has a lifetime warranty for some models’ batteries, and the batteries enjoy a trade-in discount; Jianghuai, Emgrand and Changan guarantee the battery for at least five years; Qichen reduces the repurchase fee by 10,000 for every 10% attenuation of the battery; The 8-year warranty of imported brand Tesla’s battery components is unlimited mileage.
However, there is no clear numerical value for reference. If consumers have doubts about the battery life of the purchased vehicle, the battery attenuation range will be decided by the manufacturer. A brand needs to test the battery in the store and form a report, and then the manufacturer will decide whether the vehicle is in normal attenuation, and the battery is divided into "normal attenuation" and "abnormal attenuation", and "normal attenuation" is not covered by the lifetime warranty.
According to the fact that the battery is shared with the battery, the battery is not actually a private part. In fact, it also reduces the time for rapid battery decay. According to the charging requirements of the battery in the power exchange station, the battery is uniformly charged in the constant temperature and humidity environment of the power exchange station by alternating current slow charging, so that the service life is prolonged and the loss is low. Moreover, people, batteries and cars are safer because of the operation of special personnel and robots. The battery pack can be guaranteed for 600,000 kilometers. The direct charging mode of electric vehicles, especially fast charging, is difficult to achieve attenuation of less than 20% in 8 years and 150 thousand kilometers.
Many consumers are puzzled, will there be old batteries installed in their cars, which will reduce the cruising range or cause problems in the vehicles? In fact, this problem, the power station is more worried than consumers about battery problems, or the situation of old batteries. According to Wei Lai Li Bin’s explanation, after each battery with low battery capacity is replaced in the power station, the battery detection system of the power station will be started to judge the "survival" state of this battery, and whether to save and continue to use this battery is equivalent to a "physical examination" of the battery every time it is replaced. The system will "take off the shelf" the battery that is not suitable for loading into the car, which is convenient for future use as an energy-eating battery. In this process, BAIC New Energy is also in use. Therefore, the battery in the battery replacement can be more "healthy" than in your own car.
In terms of power supply, the Specification for Power Supply System of Electric Vehicle Charging and Replacing Power Station issued by State Grid Corporation in August 2017 clearly stated that when enterprises build high/low voltage charging and replacing power stations, they need to build according to the approved design specifications for power distribution and transformation, and do a good job in the installation and operation of protective devices and related power supply design requirements. According to the scale and application situation of charging and replacing power stations, the standards of different load levels are constructed. According to the requirements, there are seven power supply design standards, including power supply requirements, power quality indicators, safety requirements, power metering, power supply monitoring functions and signs.
After consulting a large number of materials, it is found that there is only one technical specification for the construction of power exchange station, which is the Technical Specification for the Operation Management System of Intelligent Charging and Switching Service Network for Electric Vehicles Based on the Internet of Things issued by State Grid Corporation in 2011, and the development plan of electric vehicles, the development plan of charging service network for electric vehicles in the Twelfth Five-Year Plan of State Grid Corporation, is also released. At that time, the commercial operation mode of "mainly replacing electricity, supplemented by plug-in, centralized charging and unified distribution" was put forward, and the operation management system of intelligent charging and replacing service network was developed in a unified way, and the demonstration operation of charging and replacing network and battery leasing pilot were carried out. Since then, the relevant departments have failed to issue other specifications and standards for the field of electric vehicle replacement with rapid technological innovation. Until May 2012, the Development Plan of Energy-saving and New Energy Vehicles (2012-2020) issued by the State Council proposed to explore new energy vehicles, battery leasing, charging and replacing services and other business models, and encouraged the establishment of independent charging and replacing enterprises to gradually realize the marketization and socialization of the construction and management of charging and replacing facilities.
This development plan will push the field of power exchange to the market-oriented experimental period, that is, during this period, in 2016, the electric bus founded Aodong New Energy and cooperated with BAIC New Energy to promote electric taxis. Up to now, Aodong has built 81 power exchange stations in Beijing. By the end of 2017, AUTO will build and operate 130-150 power stations nationwide, which can serve 13,000-15,000 electric vehicles.
By summing up and drawing lessons from the failure of international power exchange stations, domestic power exchange stations have improved a lot in technology, such as high-power connectors. In 2016, this technology was applied in the cooperation between Aodong New Energy and BAIC New Energy to promote the replacement of electric taxis. In the 81 power exchange stations built in Beijing, Aodong New Energy adopts the high-voltage electrical connection technology with plane spring coil to solve the problem of high-power connection and ensure the follow-up when the car bumps.
Weilai is more advanced. In order to solve the subtle problems in power exchange and ensure the unification of each power exchange, Weilai has specially developed a power exchange system, which covers an area of only three parking spaces and can replace the battery of an ES8 in just three minutes. This system is highly technical and has more than 300 patents.
However, although the technology has been improved, the power station is still limited by the weather, or it cannot be replaced or has minor defects. In the few days when the author made an unannounced visit, he caught up with the heavy rain in Beijing. Due to the accumulated water, the gap between Weilai Power Station and the ground was very small, and it was easy to cause the accumulated water to flood in in the case of heavy rain. Although Beiqi New Energy’s power exchange station is relatively high off the ground, the vehicles washed by rain water enter the power exchange station with rain water, which is easy to cause the sensor to get wet, resulting in the robot arm not being able to accurately aim at the battery shell screws, and the power exchange failed in the interview. Finally, after the position is determined by the naked eye of the staff, it is replaced in place again.
Through analysis, we know that changing the power station can delay the battery decay time and greatly improve the battery life. In addition, through the relevant national codes and standards, the standards of power station construction are also being improved. As far as the former Better Place and Tesla power stations are concerned, the technical level of power station in China has reached the leading position. Looking at the whole power exchange industry from the perspective of the safety of power exchange stations, consumers can be completely at ease. In the next article of "RTS for Power Exchange" specially planned by Sina Auto, we will analyze the parts that need to be improved from the operation of the power exchange station.