Research On Routine Testing Method Of Power Lithium Ion Battery For Electric Vehicle

In recent years,the electric vehicle industry develops rapidly.The realiability and safety of power lithium ion batteries are gradually becoming the bottleneck for the healthy development of electric vehicles.In order to ensure the realiability and safety of electric cars,the power lithium ion batteries of electric vehicles are to be equipped with a battery management system(BMS).The BMS monitors and controls the main performance status parameters such as voltage,current,temperature,state of charge of the power lithium ion batteries.The testing equipment needs to have the following key technologies in order to test lithium ion batteries of the electric vehicles.At the beginning,the testing equipment needs to communicate with the BMS of the lithium ion batteries.Secondly,in order to analysis and process the data in the later period,we need to receive and translate the Controller Area Network(CAN)messages into the actual physical information.The core of this paper: according to the communication protocol between the electric vehicle the charging pile and BMS on GB/T 27930-2015,a communication method which is between the facility and the BMS of the power lithium ion batteries and a translation method from CAN to the physical information are introduced in this paper.The relevant program code is solidified into the software system control unit of the testing device.The two functions of the BMS communication and the CAN messages translation are successfully implemented in the testing device.The parameter information of the power lithium ion batteries can be obtained by a series of fast tests in order to judge the performance status of the power lithium ion batteriesThe main contents of this paper are as following:Firstly,the main parameters of the power lithium ion batteries regarding the realiability and safety was obtained by analysising the domestic and foreign testing standards of power lithium ion batteries.The necessity and significance of the routine testing methods on power lithium ion batteries are further analyzed.Secondly,one of the key technologies of the routine testing for power lithium ion batteries is to realize the communication with the BMS.According to GB/T 27930-2015,a communication method between the tester and the BMS of the power lithium ion batteries was developed and was further integrated into software system control unit of the tester.The communication with the BMS of the power lithium ion batteries was successfully released and the information of the CAN messages was collected.Thirdly,another key technology of the routine testing for power lithium ion batteries is to translate the CAN messages into actual physical information.According to GB/T 27930-2015,a method which can translate the CAN messages into actual physical information is integrated into software system control unit of the testing device.The facility has obtained the performance parameters information such as the voltage,temperature,capacity of the power lithium ion batteries.Finally,the voltage and temperature of the power lithium ion batteries can be directly obtained by the testing equipment translating the CAN messages.The testing equipment can achieve the DC internal resistance,capacity and state of charge of the lithium ion batteries by setting the experiment and analyzing and processing the experimental data.By the acquisition of the main parameters of power lithium ion batteries,the basic performance of the lithium ion batteries can be judged.The feasibility of the two methods is verified.