28 March 2016, Volume 34 Issue 6
    

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  • New energy vehicle research and development in China
    OUYANG Minggao
    Science & Technology Review. 2016, 34(6): 13-20. https://doi.org/10.3981/j.issn.1000-7857.2016.06.001
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    New energy vehicles have developed rapidly in China in recent years, and have become the brightening point in the automobile fields for technology innovation and industry upgrade. Breakthroughs in the core technology have enhanced the performances of vehicle products, and the incentive policies in market penetration have promoted the industrialization process. In this paper, the technical progress in new energy vehicle researches and applications under the national research and development programs are reviewed, and research topics in the next five years are summarized as well.
    • Spescial Issues
  • An overview of xEVs battery technologies
    HUANG Xuejie
    Science & Technology Review. 2016, 34(6): 28-31. https://doi.org/10.3981/j.issn.1000-7857.2016.06.002
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The materials, cell design, manufacturing and BMS technologies of Li-ion batteries are summarized. LiMn2O4 is widely used for light EVs and HEVs. It is also commonly used to mix with NCM for improving cell's safety and rate performance. LiFePO4 shows very high stability and it is suitable for long life and safety batteries for PHEVs and other EVs which need batteries with medium energy density and long cycling life. NCM and NCA have higher specific capacity and they are used for high energy type cells with ceramic coating layers on separator and/or electrodes for improving safety. Graphite is almost the only anode for EV cells and the effort to add Si to carbonaceous anode material is continuing. Liquid electrolyte with higher charge cutting voltage and wide working temperature range is being developed. Small cylinder cells, large size prismatic metal can cells and soft pack cells co-exist for different designs of xEVs. Machines made in China for cell manufacturing grow quickly with improved technologies. Large efforts are still to be made from xEV side and cell side to improve safety and reliability of battery packs. Li-ion battery is the best candidate of electricity storage unit for xEVs at present and in the near future. Its energy density will reach 300 (W·h)/kg at cell level in the near future and will serve the new energy vehicles in the next decade.
  • On the safety issues of lithium ion battery
    HE Xiangming, FENG Xuning, OUYANG Minggao
    Science & Technology Review. 2016, 34(6): 32-38. https://doi.org/10.3981/j.issn.1000-7857.2016.06.003
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The safety of lithium ion battery power system should be enhanced before the massive application of electric vehicles. The safety problem needs to be fully combed in order to improve the safety of the vehicle power battery system. This paper attempts to interpret the safety problem of lithium ion power battery system and to find further solutions. The safety of power battery system is divided into three levels in this paper, namely, "evolution", "trigger" and "propagation". The "evolution" refers to that the failure may be experienced a long evolutionary process before the battery safety accident occurs. The "trigger" is the turning point of the "evolution", and can also be unexpected events that destroy the power battery system upon vehicle accidents. The thermal runaway mechanism of lithium ion power battery is expounded, and different triggering ways of thermal runaway are analyzed. On the issue of the "trigger" of the safety accident of the power battery, the most critical point is the thermal runaway. Its "propagation" should be prevented when thermal runaway "trigger" occurs. Understanding more about the thermal runaway "propagation" mechanism can help designers to optimize safety design, prevent thermal runaway "propagation", and reduce the degree of damage caused by safety incidents. Based on the discussion on the "evolution", "trigger" and "propagation", this paper puts forward a number of measures for accident prevention and safety monitoring.
  • A review on the key issues of the lithium-ion battery management
    LU Languang, LI Jianqiu, HUA Jianfeng, OUYANG Minggao
    Science & Technology Review. 2016, 34(6): 39-51. https://doi.org/10.3981/j.issn.1000-7857.2016.06.004
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Lithium ion battery is widely used in new energy vehicles, given its high energy/power density, extended longevity, and environment friendliness. However, composed of hundreds of lithium ion cells, the battery system is very complex and subject to many safety constraints. Therefore, safety, durability and power output capability of lithium ion batteries must be well managed on board. It is essential for a battery management system (BMS) to guarantee that the lithium ion battery works within safe status, thereby ensuring safety, durability and power output capability of the lithium ion battery system. A typical BMS is composed of sensors, actuators, controllers, etc. The key technologies of the BMS include: sensor and signal synchronization, state estimation of cell and battery pack (state of charge-SOC, state of health-SOH, state of function-SOF, state of energy-SOE, and state of safety-SOS), cell variation identification and balancing, safe charging control, fault diagnosis, etc. Advanced BMS design requires systematic research of battery mechanism and long-time technological accumulation. Basically, performance tests and researches are essential to the characteristics and mechanisms of safety, durability and power output capability of lithium ion battery. Based on deep understanding of the battery performance, semi-empirical and empirical models can be established for cell and battery systems. Furthermore, model-based state estimation and performance optimization algorithms can be developed in BMS integration and design, and the battery system can thus safely work at its optimal status.
  • Fuel Cell Technologies for vehicle applications
    HOU Ming, YI Baolian
    Science & Technology Review. 2016, 34(6): 52-61. https://doi.org/10.3981/j.issn.1000-7857.2016.06.005
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In this paper, the state of the art of fuel cells for vehicles are reviewed. Based on the technology chain of vehicular fuel cells, the bottle-necks and research hot-points are elucidated in terms of materials, components and stacks. Particularly, the fuel cell materials include catalyst, ion exchange membrane and gas diffusion layer; the fuel cell components include membrane electrode assembly and bipolar plates; and the system components include air compressor, humidifier, hydrogen recirculation pump and hydrogen cylinder. Currently, some domestic FC materials have reached the standards of commercial products. The authors encourage industry partners to invest FC enterprises and build up relative production lines, promoting domestical FC technology progress.
  • Progress of membrane electrode assembly technology for proton exchange membrane fuel cell
    WANG Cheng, ZHAO Bo, ZHANG Jianbo
    Science & Technology Review. 2016, 34(6): 62-68. https://doi.org/10.3981/j.issn.1000-7857.2016.06.006
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Membrane electrode assembly is a key component for multiphase mass transport and electrochemical reaction, which determines the performance, durability and cost of proton exchange membrane fuel cell. In this paper, the current technology status and commercial targets for membrane electrode assembly are analyzed. After the two traditional manufacturing methods, the third generation ordered membrane electrode assembly has attracted great research interest in the fuel cell development. The latest progress of the ordered membrane electrode assembly with ultra-low Pt loading in recent years is introduced in detail. Currently the best ordered membrane electrode assembly with 0.118 mg/cm2 Pt total loading can achieve the performance of 861 mW/cm2 @ 0.692 V, 0.137 g/kW and cost of $5/kW, the Q/△T value also reaches 1.45. From the viewpoint of reducing the Pt content and reducing the cost of the fuel cell power generation system, the ordered membrane electrode assembly with the function of self-humidifiaction is an important direction in the next generation membrane electrode assembly development.
  • Power semiconductor devices used in electric vehicle drive systems
    WEN Xuhui, NING Puqi, MENG Jinlei, ZHANG Jin, LIU Jun, KONG Liang
    Science & Technology Review. 2016, 34(6): 69-73. https://doi.org/10.3981/j.issn.1000-7857.2016.06.007
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    On-board motor drive converter is the most important part of electric vehicle (EV) drive while the power semiconductor devices are its core. Comparison and analysis of EV drive converters, from mini car to big bus, are presented in terms of topology, control scheme and various key indexes such as power density etc. It is concluded that power semiconductor chip and its packaging are the highlight of innovation. The development of IGBT chip and its packaging technologies are described. The characteristics of silicon carbide are introduced. Further SiC device and its application research area are also discussed.
  • An overview of development status of traction battery industry for electric vehicles
    XIAO Chengwei, WANG Jiqiang
    Science & Technology Review. 2016, 34(6): 74-83. https://doi.org/10.3981/j.issn.1000-7857.2016.06.008
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Traction battery, as a key component, plays an important role in the mass application of electric vehicles. In the field of its R&D, US, Japan, Germany, Korea and China have all formulated their national-level plans for traction batteries respectively. In the field of traction battery industrialization, lithium-ion battery is the mainstream product, and China, Japan and Korea are the three major suppliers and competitors. Their products involve different material chemistries, capacities and manufacturing processes, the energy density ranges from 89 to 245 (W·h)/kg, and mass production is realized. The category of material chemistry and related technical parameters have also been proposed for the future traction battery industrialization. Issues faced by manufacturing equipment, material chemistry, system integration and evaluation for the traction battery are pointed out at the end of this overview.
  • Key technology of BJEV C30 electric vehicle and its demonstration applications
    CHEN Ping, LIANG Chen, SI Hai
    Science & Technology Review. 2016, 34(6): 84-89. https://doi.org/10.3981/j.issn.1000-7857.2016.06.009
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Development of electric vehicles has important implications for saving energy and emission reduction. It also can reduce the PM2.5 emissions and improve the air level, especially in the urban district. Based on market analysis and demand, Beijing Electric Vehicle Co., Ltd. has developed the C30 electric vehicle platform, which adopts a new vehicle configuration, takes power batteries as the core, and integrates vehicle safety and reliability to ensure handling and stability. Through the development and implementation of the high pressure integrated system, high voltage parts design is realized. Due to whole vehicle development and lightweight design, EV200 achieves 80 kg lighter than EV150. Based on ISO26262 and AUTOSAR4.0 standards, the integrated controller of the vehicle is improved, which combines coordination, refinement and intelligence strategies. Depending on the vehicle demand, the high energy density battery system, high efficiency permanent magnet synchronous motor and controller-integrated system are developed as well. Since its launch to the market, the C30 platform models have been sold for more than 6748 units, covering areas such as private, taxi, rental and logistics.
  • SAIC Roewe 550 plug-in hybrid electric system
    LENG Hongxiang, GE Hailong, SUN Jun, XU Zheng, WANG Lei, WANG Jian, LUO Sidong, LUAN Yunfei
    Science & Technology Review. 2016, 34(6): 90-97. https://doi.org/10.3981/j.issn.1000-7857.2016.06.010
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    RRoewe 550 plug-in hybrid electric vehicle (PHEV) is designed and developed by Shanghai E-Propulsion Auto Technology Co., Ltd (SEAT). Since its debut in early 2014 the supply has always been inadequate to the blooming market demand, thanks to its excellent demonstrated performance and reliability. An indepth analysis of the electric drive unit (EDU), which is the core technology of Roewe 550 PHEV, is presented in terms of vehicle energy economy and dynamic performance. The benchmark by THS of Prius III is used in the theoretical analysis and simulation. The authors hope that this article can provide the reader with some insights into Roewe 550 PHEV.
  • Tesla electric vehicle technology analysis
    GUO Xiaoji
    Science & Technology Review. 2016, 34(6): 98-104. https://doi.org/10.3981/j.issn.1000-7857.2016.06.011
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    This paper starts with Tesla's technology roadmap and design principle, then analyzes the technical advantages of Tesla electric vehicle from aspects of battery, motors, body materials, safety, intelligentization and charging. Finally, it explores Tesla's corporate vision from its decision of opening patents.
  • Research on car-sharing business models of electric vehicles
    DING Xiaohua, WANG Mian, CHEN Yan, ZHANG Yingjie, ZHANG Wenjie
    Science & Technology Review. 2016, 34(6): 105-110. https://doi.org/10.3981/j.issn.1000-7857.2016.06.012
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Car-sharing is an innovative business model. First, this paper presents an overview of global car-sharing development in recent years, and its rapid development in North America. Then, the paper compares, through big data analysis, the operation modes and consumer characteristics of French AUTOLIB and Chinese EVCARD, the two commercial cases of electric car-sharing. This is followed by a deeper analysis of the travel costs of the aforementioned two kinds of electric car-sharing. According to relevant computations, it is shown that AUTOLIB and EVCARD have great similarity in membership's gender structure, age distribution, average single rental mileage, and average single trip speed, and that both membership's daily lease time distributions display different consumption purposes. Besides, in comparison with taxi fares, it is found out that once a single trip time overpasses 25 minutes EVCARD has quite remarkable price competitive advantage which is only 50% price of the same city taxi fares, while the figure of AUTOLIB is 70%. In some degree this research reveals the difference between AUTOLIB and EVCARD regarding development feature and stage.

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