Design And Control Of Thermal Management System For Vehicle Power Battery Pack

Seeing the world is facing environment problems as well as energy security issues,new energy vehicles have been served as one important direction of future automotive industry.However,the bottleneck of new energy vehicle development is the Li-on battery.The key problem is that the current power battery temperature conditions and the use of vehicles operating conditions do not match.There are three major issues: 1)In low temperature environment,battery system's charging capability is getting worse,as a result vehicle's driving range is affected.2)In high temperature condition,battery's cycle life as well as calendar life,will fade significantly,and battery's safety is also concerned.3)The cell temperature variation inside the battery pack also leads to performance decay of battery pack.Therefore,it is necessary to design a thermal management system for battery pack in electric vehicle.To resolve these problems,the aim of this thesis is to design an active liquid based thermal management system.The system mainly includes: battery pack,thermal sources(both heating and cooling),control pipelines,and thermal management control unit.The thermal management unit monitors the battery cell's temperature,and controls the heating or cooling source,and utilizes different control paths by switching pumps and valves,finally keeps battery pack's temperature is proper area.The thesis delivered a detailed design of the thermal management system,which includes: thermal system architecture,battery pack system design,sensor/actuator implementation,control strategy design,and the hardware and software design.Focus on the three problems,the system has been designed,simulated and validated.Also,to evaluate the engineering feasibility,the energy consumption is considered as an important factor in design and validation.The validation result shows this thermal control system can reach all system design goals.The engineering solution have passed prototype review and bench testing,and the vehicle based validation has been in process.