EV Battery Thermal Management With Waste-Heat Feedback Control
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Solution Overview
Problem
Modern electric vehicles face challenges in managing thermal loads efficiently, particularly in heavy-duty commercial vehicles, where battery systems generate waste heat that can reduce battery lifespan and impact other system components, necessitating effective thermal management systems to maintain optimal temperatures and preserve battery capacity.
Innovation Solution
A thermal management system for electric vehicles that utilizes a battery coolant loop and a refrigeration loop, incorporating chillers, pumps, and electronic expansion valves, with a controller that adjusts compressor speed, condenser fan speed, and electronic expansion valve positions based on measured temperatures and pressures to optimize cooling and heating, thereby managing thermal loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal management system is implemented to cool the battery system, then battery lifespan and performance are improved, but system complexity and power consumption increase
Solution Approach 1:
The thermal management system is designed to perform multiple functions: cooling the battery during operation, heating the battery during cold conditions using waste heat from the exhaust manifold, and regulating temperatures across different operating conditions. This multi-functionality reduces the need for separate dedicated systems for each thermal management task.
Solution Approach 2:
The system dynamically adjusts operational parameters including coolant flow rate through the battery coolant pump, refrigerant flow through electronic expansion valves, and compressor speed based on real-time temperature sensors and battery conditions. This parameter modulation allows the system to adapt to varying thermal loads and environmental conditions efficiently.
2Reliability
If active cooling is used to maintain optimal battery temperature, then battery performance is improved, but power consumption increases
Solution Approach 1:
The system captures waste heat from the exhaust manifold that would otherwise be discarded and redirects it to heat the battery coolant during cold operating conditions. This converts a harmful waste product into a useful thermal resource, reducing the need for additional heating power consumption while improving overall thermal efficiency.
Solution Approach 2:
The thermal management system operates periodically based on detected thermal conditions rather than continuously. The controller activates the coolant pump, compressor, and expansion valves only when temperature thresholds are exceeded, allowing the system to rest and consume minimal power during stable thermal conditions.
3Loss of energy
If waste heat from the battery is utilized for heating the coolant, then thermal efficiency is improved, but control precision becomes more difficult
Solution Approach 1:
The system incorporates multiple temperature sensors positioned at strategic locations including the battery, coolant lines, and exhaust manifold. These sensors provide continuous feedback to the controller, which dynamically adjusts the operation of the coolant pump, expansion valves, and other components to maintain precise temperature control while maximizing waste heat utilization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system enhances thermal efficiency, reduces power consumption, and extends battery lifespan by maintaining optimal temperatures, ensuring efficient operation and increased vehicle range by effectively managing thermal loads in electric vehicles.
Implementation Method 1
heating, utilizing waste heat from a battery, a battery coolant of a battery coolant loop to form a heated battery coolant
Implementation Method 2
heating a refrigerant of a battery refrigeration loop by exchanging heat with the heated battery coolant
Implementation Method 3
controlling a position of a first electronic expansion valve based upon the first refrigerant temperature and the first refrigerant pressure
Implementation Method 4
compressing the refrigerant of the battery refrigeration loop after heating the refrigerant
Implementation Method 5
condensing the refrigerant of the battery refrigeration loop after compressing the refrigerant
Data Source
AI summary
The present disclosure provides a method of managing thermal loads in an electric vehicle and controlling various electronic components of a thermal management system. The method may comprise heating a battery coolant of a battery coolant loop utilizing waste heat from a battery to form a heated battery coolant, heating a refrigerant of a battery refrigeration loop by exchanging heat with the heated battery coolant, and measuring refrigerant temperature(s) and pressure(s) at an output of a chiller. The measured temperature(s) and pressure(s) may be utilized by the thermal management system as feedback signals for performing a proportional-integral-derivative control to compute an electronic expansion valve position command. Battery temperature(s) and/or battery coolant temperature(s) may be measured and utilized by the thermal management system as feedback signals for computing a pump speed command and performing a proportional-integral-derivative control to compute a compressor speed command and a condenser fan speed command.