EV Battery Cooling via External Evaporator and Thermal Conduction
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Solution Overview
Problem
Existing battery cooling systems for electric vehicles are inefficient and bulky due to the need for large radiators and fans, and they fail to effectively manage rapid temperature increases during high-power charging cycles, leading to battery degradation.
Innovation Solution
A cooling device that utilizes an air conditioner with a second evaporator located outside the battery container, in contact with a thermally conductive part such as a radiator, allowing for efficient heat exchange through natural or forced convection, and includes flexible conduits and flaps for ambient air cooling, reducing system size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling circuit with pump, radiator and fan is used to cool the battery, then the battery temperature can be controlled, but the system becomes bulky, heavy and complex
Solution Approach 1:
The patent merges the battery cooling function with the vehicle's existing air conditioning system. The AC system's evaporator, compressor, and refrigerant circulation infrastructure are combined with the battery cooling function, eliminating the need for separate cooling components and reducing overall system complexity
Solution Approach 2:
The air conditioning system is made multi-functional by enabling it to serve both the passenger compartment cooling and the battery cooling purposes. The refrigerant circulation system performs dual functions, reducing the need for dedicated battery cooling equipment
2Temperature
If the evaporator is located inside the battery tray to cool the batteries, then cooling efficiency improves, but the tray volume increases and connection becomes complex
Solution Approach 1:
The evaporator is extracted from the battery tray interior and relocated to an external position. The evaporator is mounted on the outer surface of the battery container, eliminating the need to increase tray volume while maintaining effective cooling through thermal contact with the container walls
Solution Approach 2:
The battery container wall acts as an intermediary thermal conductor between the evaporator and the batteries. The evaporator cools the container wall, which then conducts heat away from the batteries, eliminating the need for direct evaporator-battery contact
3Productivity
If rapid charging is performed to reduce charging time, then productivity improves, but heat generation increases significantly
Solution Approach 1:
The cooling system operates continuously during rapid charging to remove heat as it is generated. The refrigerant circulation maintains continuous heat extraction from the batteries, preventing temperature accumulation that would otherwise occur during high-power charging cycles
Solution Approach 2:
The heat generated during rapid charging, which is normally a harmful effect, is converted into a manageable thermal transfer problem. The refrigerant system captures and removes this heat energy, transforming the charging process into a controlled thermal management scenario that enables sustained high-power charging
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 solution effectively maintains battery temperature below 40°C, even during rapid charging, while minimizing system complexity and cost, and allows for efficient cooling without increasing the battery tray's volume or manufacturing costs.
Implementation Method 1
a second evaporator suitable for cooling the battery or batteries
Implementation Method 2
The heat exchange between the second evaporator and the inside of the tank takes place by contact between this evaporator and a thermally conductive part of the tank
Implementation Method 3
the said second evaporator is located outside the tank and is in contact with a thermally conductive part of this tank
Implementation Method 4
efficient cooling without increasing the battery tray's volume or manufacturing costs
Data Source
Figure 1~3
AI summary
The invention relates to a device for cooling the battery or batteries (11) of a motor vehicle, especially an electric vehicle, said vehicle comprising a temperature regulating unit in which the evaporator and the condenser (3) are interconnected by a main circuit (4, 5) containing a refrigerant liquid, said main circuit (4, 5) being connected to a branch circuit (7, 8) for guiding the refrigerant liquid to a second evaporator (9) for cooling the battery or batteries (11) contained in a case (10). The invention is characterised in that the second evaporator (9) is arranged outside the case (10) and is in contact with a thermally conductive (14) part of said case (10).