Pure electric bus company wrestling charging speed

In recent years, the development momentum of electric passenger cars is undeniable. Given the obvious advantages of electric vehicles in energy conservation and emission reduction, the government has given a lot of financial subsidies to purchase electric buses. Many bus companies have also launched their electric bus projects. The willingness of enterprises to take market share with the development of electric passenger cars coincides with the idea that local governments hope to improve the environmental quality through electric passenger cars.

However, in actual use, electric buses are faced with many limitations such as long battery charging time, short mileage and short service life. If they can not effectively solve the contradiction between charging speed and mileage, the further development of electric bus is bound to be hindered .

In the "12th Five-Year" national "863" program with the support of lithium-ion battery technology research has made major breakthroughs, at present the vast majority of domestic electric bus companies using lithium iron phosphate technology, lithium iron phosphate battery technology in theoretical research and market applications Are mature. The lithium titanate battery technology to adapt to the rapid performance of the excellent cause of electric bus industry widespread concern. Foreign lithium titanate battery technology research tends to mature, there are already domestic examples of lithium titanate battery rapid charging technology. Recently, the reporter interviewed a number of electric bus companies to understand the lithium iron phosphate technology and lithium titanate battery technology in the charging speed of the latest developments.

Lithium titanate battery technology to achieve rapid charging

In April 2011, Chongqing Bus Company purchased 6 Hengtong fast-charging pure electric buses and invested 609-line demonstration operation. This is the world's first demonstration of fast charging electric bus running circuit. After more than a year of operation, traveling 50,000 km, charging more than 2,000 times, experienced a mountainous area in Chongqing and 44 ℃ high temperature test.

In July 2012, Chongqing Bus re-entered 25 fast-charging electric buses in the airport area for commercial operation. The route is 34 kilometers long and has a steep slope. It runs 170 to 200 kilometers per day and charges 5 to 6 times for each charge of 8 ~ 10 minutes.

This fast-charging pure electric bus using lithium titanate battery technology, lithium titanate battery technology has drawn widespread concern in the electric bus industry for some time, with lithium titanate battery technology, electric bus can achieve rapid charging, mileage on the Requirements are relatively low, a single charge can be completed only need to reach the mileage of the bus shuttle back and forth distance can be shorter charging time to ensure that the electric bus on time operation. Because do not need full charge and discharge, coupled with the chemical composition of lithium titanate, lithium titanate battery life can usually reach 6 to 8 years.

Despite the advantages of short charging time and long battery life, lithium titanate batteries have the disadvantage of large charging load (a charging pole needs 450 kilowatts). The promotion of mass production is limited by the construction of charging stations. Therefore, in the development of lithium titanate Battery technology at the same time must consider the latter part of the electric bus operation of the market, with particular emphasis on the construction of charging stations.

Reporters learned from relevant responsible persons that SGCC built the world's first large-scale bus rapid charging station at Chongqing Airport Bus Terminal in June 2012 and set up 6 double-gun charging posts for 40 to 50 fast-charging passenger cars Charging, by the bus driver on their own charge. Charging station construction investment of about 15 million yuan, the charging method is exactly the same with refueling. Charging station covers an area of ​​more than 1000 square meters, provided by the local bus company to provide land, the State Grid to provide funding and power sources, and is responsible for specific construction issues. At present, the charging station can fully meet the Chongqing city in the use of lithium titanate battery bus charging needs. In order to further develop the fast-charging electric bus, Chongqing is building another fast charging station, and another fast charging station is in the demonstration stage.

According to the relevant person in charge of Hengtong introduction, lithium titanate batteries have now been able to achieve single-cell high rate (6C) full charge and discharge conditions to achieve 20,000 cycles, the battery attenuation of less than 20%, after the group can reach 10,000 to 12,000 cycles , Fast-charging pure electric bus only loaded 140 Ah battery life mileage of 40 to 50 kilometers.

Traditional lithium technology charging speed has improved

Compared to lithium titanate battery technology, lithium iron phosphate battery technology and lithium manganese oxide battery technology is the traditional lithium battery technology, but also the current mainstream lithium battery technology, Japan and South Korea's main lithium-manganese battery technology, the United States main lithium iron phosphate battery Technology route, China electric bus industry to use lithium iron phosphate battery technology.

Lithium manganese oxide battery technology and lithium iron phosphate battery technology in the theoretical research and market applications have been more mature, but both battery technologies exist slow charging technology, although the battery life can be extended to make up for charging speed Slow defects, but to extend the range of mileage means that more batteries must be used. The increase in the number of batteries will lead to an increase in the cost of the vehicle as well as an increase in the weight of the vehicle body, which will affect the enthusiasm of the bus company in using the electric bus. At the same time, an increase in the weight of the vehicle will also affect the number of passengers and the normal use of the vehicle. How to handle the contradiction between charging speed, battery cost, mileage and normal operation of electric bus is the question that electric bus companies that use lithium iron phosphate battery technology must think at present. Reporters interviewed a number of electric bus industry learned that lithium iron phosphate battery technology has greatly improved the charging speed, while reducing battery costs and extend battery life has also made great progress.

According to the relevant person in charge of Anhui Ankai Automobile Co., Ltd., Ankai electric buses are currently using lithium iron phosphate battery technology, battery life up to 230 ~ 260 km, to meet the needs of the city bus running a single day, full of electricity needs It took 4 hours. As the battery life mileage can meet the needs of single-day operation of electric buses, the problem of longer charging time will not affect the normal use of buses, and the use of lower electricity prices at night to achieve peak-shifting charging and reduce the operation of electric buses cost. Ankai pure electric bus since 2010, a large-scale operation of the market, so far the operation of the Ankai pure electric bus as a whole in good condition.

Suzhou Jinlong Bus is an important enterprise that develops and produces pure electric bus. Suzhou Jinlong Pure Electric Bus adopts both lithium iron phosphate battery technology and ternary lithium manganese battery technology. According to the relevant person in charge of Suzhou Golden Dragon introduction, Suzhou Jinlong pure electric bus mileage of up to 220 kilometers, to meet the needs of a single bus operation. The battery charging speed is shortened to one and a half hours, the vehicle purchase cost of about 2000000 yuan, 500000 yuan subsidies, local government in Jiangsu subsidies 500000 yuan, the battery design life of 3 years 150,000 kilometers and 4 years 20 Two thousand kilometers. Suzhou Jinlong pure electric bus in the market has been more mature use of a lot of procurement of Suzhou Jinlong pure electric bus company reflects the Suzhou Jinlong pure electric bus in the actual use of the security risks are small, battery storage capacity in the design cycle No obvious.