Battery Cooling Loop Using Flow Boiling for Fast Charging
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Solution Overview
Problem
Conventional battery cooling systems for electric vehicles are heavy, noisy, inefficient, and not optimized for battery pack cooling, leading to reduced battery life during fast charging due to high temperatures.
Innovation Solution
A battery cooling system that uses a refrigerant with a boiling temperature between 30° C to 55° C, operating without a compressor or expansion valve, employing forced liquid convection and boiling modes to manage heat, and integrating with the vehicle's HVAC system for auxiliary cooling, with sensors and variable speed components to adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional HVAC systems with compressors are used for battery cooling, then cooling capability is provided, but weight increases, noise and vibration increase, and cost increases
Solution Approach 1:
The patent removes the compressor from the conventional HVAC system, extracting the harmful component that generates noise, vibration, and excessive weight. The cooling system operates without a compressor by using a refrigerant that evaporates at battery operating temperatures, eliminating the need for mechanical compression while maintaining cooling capability.
Solution Approach 2:
The patent replaces the mechanical compressor-based cooling system with a phase-change-based cooling system. Instead of using mechanical compression to achieve cooling, the system relies on the natural evaporation and condensation of a specially selected refrigerant (such as Novec 649 or CO2) that operates at atmospheric or near-atmospheric pressure, substituting mechanical action with thermodynamic phase transitions.
2Temperature
If conventional HVAC systems with compressors are used for battery cooling, then cooling capability is provided, but noise and vibration increase
Solution Approach 1:
The patent removes the compressor from the conventional HVAC system, extracting the harmful component that generates noise, vibration, and excessive weight. The cooling system operates without a compressor by using a refrigerant that evaporates at battery operating temperatures, eliminating the need for mechanical compression while maintaining cooling capability.
Solution Approach 2:
The patent replaces the mechanical compressor-based cooling system with a phase-change-based cooling system. Instead of using mechanical compression to achieve cooling, the system relies on the natural evaporation and condensation of a specially selected refrigerant (such as Novec 649 or CO2) that operates at atmospheric or near-atmospheric pressure, substituting mechanical action with thermodynamic phase transitions.
3Temperature
If conventional HVAC systems are used for battery cooling, then cooling is provided, but efficiency is reduced
Solution Approach 1:
The patent changes the key parameter of refrigerant boiling point to match battery operating temperatures. By selecting refrigerants with boiling points between -30°C and 50°C (such as Novec 649 with -12°C boiling point or CO2 with -78°C sublimation point), the system achieves efficient heat transfer at atmospheric pressure without requiring high-energy compression cycles, thereby improving overall cooling efficiency.
Solution Approach 2:
The patent utilizes phase transitions (evaporation and condensation) of the refrigerant as the core cooling mechanism. The refrigerant evaporates at battery operating temperatures, absorbing heat directly from the battery, and then condenses elsewhere in the system, releasing the absorbed heat. This phase-change-based cooling is inherently more efficient than conventional compressor-based systems for battery temperature ranges.
4Productivity
If fast charging is performed, then charging speed increases, but battery temperature increases reducing battery life
Solution Approach 1:
The patent utilizes phase transitions (evaporation and condensation) of the refrigerant as the core cooling mechanism. The refrigerant evaporates at battery operating temperatures, absorbing heat directly from the battery, and then condenses elsewhere in the system, releasing the absorbed heat. This phase-change-based cooling is inherently more efficient than conventional compressor-based systems for battery temperature ranges.
Solution Approach 2:
The patent implements continuous cooling during fast charging operations. The cooling system operates concurrently with fast charging, with the refrigerant continuously evaporating to absorb heat generated during charging and condensing to reject the heat externally. This continuous cooling action maintains battery temperature within optimal ranges throughout the entire fast charging process, preventing temperature-related degradation.
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
Enables fast charging without the drawbacks of compressor-based systems, providing enhanced cooling power and extending battery life by maintaining temperatures within optimal ranges, while reducing weight, noise, and vibration.
Implementation Method 1
During fast charge and discharge operation, flow boiling is performed in the coolant loop and the first refrigerant between the evaporator and the condenser is in a liquid and vapor state
Implementation Method 2
an evaporator having a first body including an exterior surface arranged in contact with the battery pack and a first channel
Implementation Method 3
A condenser includes a second body with a second channel having an inlet and an outlet
Data Source
AI summary
A battery cooling system for a battery pack includes an evaporator having an exterior surface arranged in contact with the battery pack, an inlet and an outlet. A condenser has an inlet and an outlet. A pump has an inlet and an outlet. A first conduit connects the outlet of the evaporator to an inlet of the condenser. A second conduit connects the outlet of the condenser to the inlet of the pump. A third conduit connects the outlet of the pump to the inlet of the condenser. A fan is arranged adjacent to the condenser. During operation, a first refrigerant flows through a coolant loop passing through the evaporator, the first conduit, the condenser, the second conduit, the pump and the third conduit. During normal charge and discharge operation, liquid phase cooling is performed and during fast charge and discharge operation, flow boiling is performed.