As the cleanest energy source, hydrogen energy was widely used at the Beijing Winter Olympics. In addition to the full use of hydrogen energy in the torch, hydrogen fuel cell vehicles have also achieved large-scale demonstration operation in various competition areas of the Winter Olympic Games. However, the leap from fuel vehicles to hydrogen energy vehicles is not simply from "burning oil" to "burning hydrogen", behind which is the exploration and application of a series of the latest technologies such as the core technology of hydrogen fuel cell engines, multi-coupling safety technologies, and all-climate power battery technology.
Carbon emissions were reduced by 94.8 kg per 100 km
"A hydrogen fuel cell is actually a power generation device that can continue to operate as long as there is hydrogen as an energy source." As the core supplier of fuel cell engines for the Beijing Winter Olympics, Yu Min, executive deputy manager of Beijing Yihuatong Technology Co., Ltd., said that hydrogen fuel cell vehicles are an important technical means to achieve energy transformation and green and low-carbon development, compared with traditional vehicles, their energy conversion efficiency can reach more than 65%, 2 to 3 times that of the internal combustion engine, and the engine working temperature is lower, the operating noise, vibration is smaller, and the vehicle comfort performance is better.
Hydrogen energy buses running in the Winter Olympic Games area (Courtesy of Beijing Yihuatong Technology Co., Ltd.)
The hydrogen energy bus serving the Winter Olympic Games only takes 10 to 15 minutes to ensure that the vehicle travels about 300 kilometers, and the single hydrogen refueling endurance of the group car can reach 500 kilometers, which greatly saves the fuel refueling time compared with electric vehicles.
However, hydrogen is chemically reactive and easy to escape when stored. In order to ensure vehicle safety, the cylinders loaded with hydrogen have high strength, high durability, high reliability, and place parts related to hydrogen fuel in an open environment, making it difficult for hydrogen to accumulate at high concentrations. The car is also equipped with a hydrogen system leak monitoring and early warning system, which can immediately sense and close the cylinder valve once a leak occurs.
Yu Min introduced that the hydrogen fuel cell engine only produces electricity, water and heat during operation, compared with fuel buses, fuel cell buses can reduce carbon dioxide emissions by 94.8 kg per 100 kilometers. The application of hydrogen energy vehicles in the Winter Olympics has practiced the concept of "green Olympics" and can also enhance the public's awareness of green travel. After the End of the Winter Olympics, the vehicles will be converted to local buses and group cars for continued use.
Can also be quickly "started" in low temperature environment
The 212 hydrogen-fueled buses put into use in Yanqing All apply all-climate power battery technology, and even if they are parked for a long time in an environment of minus 30 degrees Celsius, the power battery can quickly heat up to a reasonable operating temperature within a few minutes.
All-climate power battery (Courtesy of Rongsheng Mengguli New Energy Technology Co., Ltd.)
As a member of the R&D team of the all-climate power battery technology, Mao Yongzhi, chief engineer of Rongshengmeng Guli New Energy Technology Co., Ltd., introduced that in the cold environment, the low temperature cold start of hydrogen fuel cells still needs lithium battery assistance to adapt to the complex and rapid winter Olympic security needs. Lithium-ion batteries have poor low-temperature discharge performance, and low-temperature charging can easily lead to the precipitation of lithium, "the poor experience of consumers is the main reason why new energy vehicles are difficult to promote in cold areas."
Technicians adopt a sandwich structure design, the high-power metal heating sheet and the battery plate are arranged and connected at intervals, which can greatly increase the heat transfer area, shorten the heat transfer distance, and use the battery's own energy for rapid heating. Considering factors such as economy, safety, and controllability, the all-climate power battery is heated from minus 20 degrees Celsius to above zero 10 degrees Celsius, which only needs to consume 4.5% of its own electricity, and the endurance can increase by 10% to 30%.
Mao Yongzhi introduced that allowing the vehicle power battery to work in a reasonable temperature range can improve the power performance of the vehicle in a low temperature environment and extend the driving range. Whether the vehicle is in driving, staying or charging, the heating system works, quickly raises the battery temperature to normal operating range, and ensures battery safety through temperature control devices.
Add a "heart" to boost power performance
The steep curves and steep slopes of the mountain road leading to the National Alpine Ski Center are no small test for the mountain operation ability of hydrogen buses. At present, the use scenarios of new energy buses are mostly flat urban roads. And the bus is heavy, the corner is bound to slow down first, the driver frequently ramps up on the slope curve, the passenger's riding comfort declines, and they will experience a sense of frustration. If not handled properly, there may also be a risk of slipping.
Dual motor coupling automatic variable speed electric drive system without power interruption (Courtesy of Beijing Polytechnic Huachuang Electric Vehicle Technology Co., Ltd.)
Zhao Mingjie, an engineer of Beijing Polytechnic Huachuang Electric Vehicle Technology Co., Ltd., who participated in the research and development of the "dual motor coupling automatic transmission electric drive system without power interruption", introduced that the new energy vehicles on the market are mostly single motor direct drive or design with transmissions, and the dual motor structure used by hydrogen energy buses in Yanqing District is equivalent to one more "heart" of the vehicle, even if one motor power is cleared when shifting gears, the other can still continue to output power to ensure smooth operation of the vehicle.
Through technical research, the scientific research team has realized the integrated design of dual motors and gearboxes, and the power controller has realized the efficient coordination of the two motors, the overall power performance of the vehicle has been significantly enhanced, and the energy consumption of 100 kilometers has been reduced. Zhao Mingjie said that after repeated tests and verification, compared with the single motor power system, the new system has performed well in six aspects: torque, power, climbing, speed, comfort and economy.