The domestic new energy bus technology line is becoming more and more unified

Bus shows will not be bustling without new energy buses.

At the Beijing Road Transport Vehicle Show, new energy buses are still the focus of the audience. The first commercial vehicle network reporter noticed that not only CSR, Yutong, Suzhou Jinlong, Foton, Jindu, Dajinlong, and youth seven hybrid buses were competing on the same stage, but also Ankai, Shaolin, Changlong and FAW. , Shen Long, CSR, Hagrid, Zhongda and other 8 pure electric buses compete for each other.

Judging from the vehicles participating in this exhibition, whether it is a hybrid bus or a pure electric bus, the technical route has a trend of unification.

Pure electric: more use of lithium iron phosphate battery pack super-capacity mode getting hot This reporter learned that in the exhibition of eight pure electric passenger cars, the use of lithium iron phosphate batteries. Among them, Ankai, Changlong Jiangsu, and Shanghai Shenlong are bus companies using the technical route of ultracapacitors of lithium iron phosphate battery packs.

It is understood that battery life has always been a major obstacle to the development of pure electric vehicles, for pure electric passenger cars, the power battery components that can be carried are lithium iron phosphate batteries and lithium manganate batteries. But at present, why domestic bus companies are so fond of lithium iron phosphate batteries?
“The reason why we use lithium iron phosphate batteries is because it is more stable than manganese batteries.” A technician from Shenzhen Century New Energy Battery Co., Ltd. who is in charge of its battery pack is on the stand of Jiefang pure electric bus. Said. According to him, lithium iron phosphate batteries have the characteristics of faster charge and discharge speeds, higher capacity, and higher temperature resistance than lithium iron manganese batteries. More importantly, lithium iron phosphate batteries also have higher reliability than lithium manganate batteries. If it is not properly controlled, lithium manganate will most likely explode under strong collisions. "But it cannot be denied that lithium iron phosphate batteries also have its drawbacks. For the moment, the capacity of lithium iron phosphate batteries has reached the limit. In other words, the mileage of a single charge of lithium iron phosphate battery is difficult to improve at the present level."

Therefore, various bus companies are trying to improve the utilization efficiency of lithium iron phosphate batteries, and the technical route of the lithium iron phosphate battery pack super capacitors is an extremely popular exploration.

“The start-up and stop of pure electric buses is the time when most of the power is consumed. The supercapacitors provide instantaneous power output, which is complementary to the backup power supply of the engine or other uninterrupted system. It just can relieve the discharge capacity of the battery pack at this time. Improve the use efficiency of the battery pack. In addition, the super capacitor also has the effect of improving the charging efficiency and reducing the charging time, said Shanghai Shenlong technical staff.

The same way of using this model, the Ankai quick-change pure electric bus, emphasizes the quick change of battery. “A safe value has been set on the electric bus, and about the number of kilometers to travel will be without electricity. The driver will know at a glance. When there is insufficient power, the driver can contact in advance and the staff will be on the platform. Prepare to make a change.” In addition, it is understood that Ankai also signed an agreement with Guoxuan Hi-Tech and the State Grid to standardize battery and battery replacement and distribution to facilitate the operation of staff.

Hybrid power: the degree of localization of the technical route is mainly based on the parallel system
The hybrid exhibition car at the auto show is the most technical route used in parallel, and there is also a clear trend that the degree of localization of hybrid powertrains is increasing.

CSR Hybrid Bus Participating in the Exhibition

It is understood that in accordance with the combination of the engine and the motor, the hybrid bus has three types: tandem type, parallel type and series-parallel hybrid type. "The two parallel-parallel hybrid systems can work together at the same time, or they can work independently to drive the car. This system is suitable for a variety of driving conditions, especially for complex road conditions. It also has a simple structure and The advantage of low cost. The form of series connection is equivalent to the role of the engine only as a generator, and its operation is only to supply the electric power needed for the vehicle. There are very few vehicles currently using this route." Hybrid in the era of CSR At the bus booth, a researcher told reporters.

The technician said that the CSR era hybrid system is almost entirely self-developed. "The CSR Times has built asynchronous and permanent magnet motor drive systems, complete vehicle control systems, moderate and deep hybrid systems, and pure electric systems. The electric vehicle technology development platform has relatively complete intellectual property rights."

Next to the Daikin Dragon Hybrid Bus, the reporter learned that although its system is not independently developed by Xiamen Jinlong, the hybrid system developed by Guangxi Yuchai is used, with the Lithium Manganese Lithium Manganese battery of CITIC Guoan League and the 6th block of Chongqing Lijiang. AMT transmission. “This car, we have been conducting relevant tests in Xiamen before, and also used the hybrid system of Eaton and other international brands in the United States, but in comparison, the current system is optimized.”

Although Zhongtong Hybrid Bus did not come to the exhibition, at the exhibition site, Yu Chunyin, deputy general manager of Zhongtong Bus, told reporters that Zhongtong's 10-meter long parallel hybrid electric-electric hybrid bus adopts a coaxial parallel structure, with Low-speed high-torque permanent magnet synchronous motor coaxial layout, with a compact structure, high mechanical efficiency and good reliability. "In short, its greatest advantages lie in much lower energy consumption, higher cost performance, and major components that are all independently developed by China."