Experimental Investigation Of Battery Parameters In The Thermal Management

Now the new energy vehicles has been widespread concern around the world. As the core of pure electric vehicles, the performance and cycle life of power Battery determines the Usability and cost of the vehicle. Battery thermal management system sensitively affect the battery performance. This paper studies the battery temperature control rules and methods in the liquid-type BTMS, and to Explore the influence of the battery performance by BTMS from the point of view battery characteristic parameter. Looking for a suitable thermal environment and working status of the battery.First of all, researcher established a method to quickly determine the initial SOC of battery, this approach from the perspective of power and energy combines with the open circuit voltage. Good to make up for the shortcomings of Ah Law.Then the researchers set up a test bench, including the charge and discharge system, circulatory system and many more. At the same time, the researchers designed software programs and hardware devices of control system, and to analyze the monitoring and control method of this experiment. Researcher used LabVIEW software to edit some experimental procedures for Improving the automation of experiments. These programs increase work efficiency to make experimental control and data more accurate. Researcher summed up a corresponding conclusions from Sensitivity, timeliness and handling of Inlet temperature and coolant flow rate.After the completion of building test bench and setting experimental methods, researcher study the performance of the battery pack in discharge and charging condition. Experiment control variable to set different boundary condition values for operating temperature(10℃,30℃,45℃),discharge rate(1C,1.5C,2C)and charging current(10A,15 A,20A). Researcher analyzed variation of battery performance In battery thermal management system.In discharge experiments, researcher analyzed the effect of temperature and discharge rate on voltage,SOC and heating power. The following conclusions:Low temperature and high discharge rate make battery performance deteriorate, and high temperature and low discharge rate effect the balance of battery voltage. Temperature affects the battery’s energy efficiency, The lowing of temperature makes the actual available capacity reduce, after discharge residual energy increases. But the discharge rate has little effect on the actual available capacity of the battery.In the late of discharge, the battery heating power increases rapidly, and a sharp decline in output, but the total power change is not large, this is a conservation imagination. So, in practical applications when the battery is discharged to the Late stage, we should pay more attention to the loss of battery output power and the rise of temperature, avoid the shortages of battery output power and high temperature with taking timely measures.In charging experiment, the researcher analyzed the influence of temperature and charging current on the battery voltage, the charging time and the heating power. The following conclusions:High temperature and high charging current increase the total value of the battery voltage and the imbalance of battery, and charging current is much more sensitive than the charging temperature in the influence on voltage.High temperature and high charge current can reduce the charging time, but it will damage the battery too, in practical applications we should control the charging temperature and charging current to reduce not only the charging time but also the charging damage. This requires to grasp the highest point of efficiency in the experiment and practice.The higher the temperature and the smaller the heating power, large charging current make the heating power increases.