Test And Research Of The Performance Of BEV

Due to the energy crisis and environmental pollution problems, electric vehiclesas the ideal means of transport in the future, has been widespread attention. However,due to the current immaturity of technology of it, and therefore cannot meet the needsof consumers. In order to improve the performance of electric vehicles, theresearchers are increasing emphasis on testing of electric vehicles in domestic andoverseas. But current domestic-related testing works are not perfect. So it is moreimportant and urgent to formulate feasible test scheme and test performance of EVand put forward the optimization suggestion of EV.Firstly, on the basis of domestic and international electric vehicle test-relatedinformation, this paper presents several easy evaluation indicators, such as indicatorsof power, economy, battery safety availability. These indicators represent the abilityof the power system through the transmission output, energy consumption per unitdistance, battery voltage and temperature variations before and after work, etc. Thenon the basis of these indicators, this paper presents the evaluation indicators of keycomponents such as operating characteristics of motor, battery dischargecharacteristics. These indicators focus on torque characteristics, speed characteristicsand efficiency of motor, consistency and discharge efficiency of battery pack. Finally,theoretical mathematical models of vehicle efficiency and driving range wereanalyzed. Through in-depth analysis on subjects, this paper established energyefficiency mathematical model of BEV and found that the most obvious influences onenergy efficiency of pure electric vehicles are transmission, motor and battery. Andthis paper proposed energy efficiency indicators to evaluate energy loss of some keyparts such as batteries, motors, transmission. On the basis of the mathematical modelof driving range, this paper found that battery voltage, capacity, depth of discharge,discharge efficiency, motor efficiency, transmission efficiency, body weight, roadrolling resistance coefficient, air resistance coefficient, frontal area, speed and otherfactors will affect the vehicle’s driving range. Regard to the limited conditions andcapacity, this paper proposed several influencing indexs, such as battery voltage, battery capacity, vehicle weight, driving speed, motor power and so on.Then this article describes the main principles of the dynamometer test, relativeperformance of vehicle and the main test equipment. And this article used domesticstandards as reference guide, and formulated test methods of internal resistance,rolling resistance coefficient of bench and obtained bench resistance and rollingresistance coefficient by testing and analyzing. Then based on the principles of forceof pure electric vehicles on the bench and working conditions, the loading force wasdetermined by calculating in this paper. At last, this article formulated specific testmethods such as dynamic performance, economic indicator, safety and availabilityindicators of battery, part characteristics of the motor and battery, and vehicleefficiency and so on. At the same time, methods of processing and analysis ofexperimental data were described in this paper.According to the test method, this paper carried a lot of bench test on EV.Through the processing and analyzing of experimental data, this paper receiveddynamics parameters, economic parameters, safety and availability indicators ofbattery, part characteristics of the motor and battery, and also discovered that motor isthe biggest factor affecting efficiency of EV and some influence law of battery size,weight, speed and other factors on the mileage of the vehicle. For example, accordingto the results of test, this paper found that dynamic performance of vehicle andconsistency and safety of batteries are good, and energy consumption per kilometer isonly0.09kWh. And this paper found that motor efficiency is most impact on theefficiency of BEV, so the designing of motor is very important. Also we found thatbattery have the strongest influence with driving range. The second one is vehicleweight. The third one is speed. The fourth one is motor power. In the end, accordingto the test results and related information, this paper puts forward some suggestions tooptimize the design of EV. Such as, selection of battery parameter, group technologyof battery, heat management of battery, designs of motor, the control methodoptimization and lightweight body and so on.At last, the current problems and future study direction are briefly discussed.