EV Battery Thermal Management With Ejector-Assisted Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery thermal management systems for electric and hybrid electric vehicles lack energy efficiency and complexity, failing to effectively manage temperature during high-speed charging and do not incorporate energy boosting elements to reduce power consumption.
Innovation Solution
A dual-evaporator vapor compression system equipped with an ejector to boost compressor inlet pressure, utilizing directional control valves and a controller to optimize refrigerant and coolant flow for efficient temperature control in both heating and cooling modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional vapor compression system is used for battery thermal management, then the system can cool the battery, but the power consumption is high and energy efficiency is low
Solution Approach 1:
The ejector changes the operating parameters of the refrigeration cycle by increasing the inlet pressure to the compressor, which reduces the compression ratio and power consumption while maintaining cooling effectiveness
Solution Approach 2:
The ejector acts as an intermediary device that uses the expansion of high-pressure refrigerant to drive the suction of low-pressure refrigerant, replacing part of the compressor's work and reducing overall power consumption
2Adaptability or versatility
If separate HVAC and battery cooling systems are used, then each system can be optimized independently, but the system complexity increases
Solution Approach 1:
The patent merges the HVAC and battery cooling systems into a single integrated refrigeration cycle, sharing common components such as the compressor, condensers, and ejector, thereby reducing system complexity while maintaining independent control capabilities through dedicated expansion valves and flow control mechanisms
Solution Approach 2:
Common components in the integrated system serve multiple functions: the first condenser can cool both cabin air and battery coolant, the second condenser can heat the battery, and the ejector enhances the performance of the entire refrigeration cycle for both cooling applications
3Reliability
If the compressor always operates to cool the battery, then the battery temperature can be controlled, but the energy efficiency decreases
Solution Approach 1:
The system dynamically adjusts the refrigeration cycle operation by controlling the ejector and expansion valves to match the actual cooling demand of the battery, avoiding continuous full-power compressor operation and improving energy efficiency while maintaining temperature control
Solution Approach 2:
The system uses temperature sensors and control logic to monitor battery temperature and adjust the refrigeration cycle operation accordingly, activating cooling only when necessary and modulating the ejector and valve positions to optimize energy efficiency based on real-time conditions
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
The system enhances energy efficiency by reducing power consumption and simplifies installation and operation, effectively managing battery temperature during high-speed charging.
Implementation Method 1
an ejector to boost compressor inlet pressure
Implementation Method 2
a first condenser for heating a passenger cabin of the EV, a second condenser for heating the battery
Implementation Method 3
a compressor, a chiller for cooling the battery
Implementation Method 4
a first condenser for heating a passenger cabin of the EV, a second condenser for heating the battery
Implementation Method 5
a first evaporator for cooling the passenger cabin
Data Source
AI summary
A battery thermal management system (BTMS) for an electric vehicle and a hybrid electric vehicle is provided. The BTMS includes a refrigerant circuit having an evaporator, a chiller, one or more condensers, a compressor, an ejector, a primary directional control valve (DCV), a secondary DCV, an ejector DCV, a compressor input and output DCVs, a reference DCV, throttling valves, and controller to cool or heat the battery and passenger cabin. A coolant circuit having the battery, battery cooler, a battery output DCV, and a battery input DCV is communicated with the refrigerant circuit via the chiller. The battery input and output DCVs are coupled to the battery cooler and coupled to each other to isolate the refrigerant circuit. The controller controls the DCVs based on an optimal battery temperature range, coolant temperature, ambient temperature, passenger cabin temperature, and optimal passenger cabin temperature range.