ABSTRACT
In order to reduce the dependence of oil and the vehicle exhaust, many countries have paid more and more attention to the development of electric vehicles. However, the capacity and the power of battery are lower than the fuel. It caused that the driving distance of electric vehicle is limited by the battery [1]-[6]. The inconsistency of battery is one of the most important problems about the short-driving distance of electric vehicle [7]-[11]. The problem will become worse together with the growth of using time and the increase of aging degree. It aects the battery characteristic and the operating eciency of electric vehicle. The battery consistency detectors and the battery maintenance are important in the City-Business-Scale of electric vehicle. Without battery consistency detection and battery maintenance, the battery may damage and the economic performance of electric vehicle operation may be aected. In order to define the battery consistency, Reference [12] proposed a method about the battery discharging capacity consistency and the battery discharging voltage consistency base on standard deviation. However, it didn’t solve the problem about the evaluation of battery consistency. Reference [9] built a mathematical model about the relationship between battery consistency and the service life and defined the damage coecient of battery capacity. The method can be used in the estimation of battery life, but it can’t be used in real-time operation. Reference [13] evaluated the circulation characteristics of battery and determined the battery cycle life formula. However, it was also dicult to solve
the problem of real-time detection and maintenance. Reference [14] evaluated the SOC of the battery and the battery life state by the Kalman filter method. The method can reflect the intrinsic characteristics of the battery. But it was dicult to accomplish in vehicle control unit (VCU). Reference [15] proposed a consistency evaluation method based on the standard deviation of voltage. Because the working voltage of battery may change with the current and the temperature, error appears in real-time operation. According to the dierent characteristics of battery in dierent aging levels, four maintenance strategies in dierent aging levels were introduced in this paper. And the Lithium-ion+ battery consistency based on the resistance was studied. A consistency evaluation method based on resistance standard deviation was proposed. The electric vehicle test was carried out to verify the eectiveness of the new method.
