Two-Phase Battery Pack Cooling for Thermal Runaway Mitigation
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Solution Overview
Problem
Current thermal management systems for large metal-ion battery packages, such as lithium-ion batteries in aircraft, are inadequate for reliable heat dissipation and fire safety, especially during thermal runaway failures, and external fire protection systems are difficult to implement effectively.
Innovation Solution
A thermal management system utilizing a two-phase coolant flow with thermally conductive inter-cell separators, condenser heat exchangers, and suppressant nozzles to manage thermal energy and mitigate fires, incorporating a coolant that changes phase from liquid to vapor at 10-45°C, enhancing heat transfer and fire suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air cooling is used for battery packages, then the system is simple and easy to implement, but heat dissipation efficiency is insufficient and fire safety is compromised
Solution Approach 1:
The patent employs a two-phase coolant system utilizing phase change (liquid to vapor) for highly efficient heat removal from battery cells. The coolant circulates through channels in contact with battery surfaces, absorbing heat during evaporation and releasing it during condensation in an external heat exchanger, achieving superior thermal management compared to simple air cooling
Solution Approach 2:
The invention leverages phase transition of the coolant from liquid to vapor state during heat absorption from battery cells, and from vapor back to liquid in the condenser. This phase change mechanism provides high latent heat transfer efficiency, enabling effective heat dissipation while maintaining system compactness
2Reliability
If external fire protection systems are installed, then fire mitigation capability is improved, but system complexity and difficulty of implementation increase significantly
Solution Approach 1:
The two-phase coolant system serves dual functions: thermal management during normal operation and fire suppression during thermal runaway events. The same coolant that cools the batteries also acts as a fire suppressant when injected through nozzles, eliminating the need for separate fire protection systems and reducing overall system complexity
Solution Approach 2:
The system uses its own coolant resource for both cooling and fire suppression purposes. The coolant circulates through the thermal management system and can be redirected through suppressant nozzles to extinguish fires, making the system self-sufficient and avoiding additional fire protection infrastructure
3Temperature
If thermally conductive inter-cell separators are used, then heat transfer between cells is improved, but risk of thermal runaway propagation increases
Solution Approach 1:
The inter-cell separators incorporate thermally conductive materials specifically at strategic locations to enhance heat removal from individual cells to the coolant system, while the overall separator structure maintains thermal isolation between cells. This localized thermal management prevents runaway propagation by quickly extracting heat at critical points without creating thermal bridges between cells
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 efficiently dissipates thermal energy and prevents or mitigates thermal runaway by using a two-phase coolant flow with phase change and suppressant nozzles, ensuring reliable operation and safety in battery packages.
Implementation Method 1
incorporating a coolant that changes phase from liquid to vapor at 10-45°C
Implementation Method 2
utilizing a two-phase coolant flow
Implementation Method 3
the flow of coolant changes phase from liquid to vapor phase in a range of 10 degrees to 45 degrees Celsius
Implementation Method 4
condenser heat exchangers
Implementation Method 5
thermally conductive inter-cell separators
Data Source
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AI summary
A battery system of an aircraft includes one or more battery packages. Each battery package includes a plurality of battery cells. A thermal management system is fluidly connected to the one or more battery packages. The cooling system has a flow of coolant flowing therethrough. Thermal energy is dissipated from the one or more battery packages via a phase change of the flow of coolant. A method of managing thermal energy of a battery package includes conducting thermal energy from a plurality of battery cells via a conductive inter-cell separator located between adjacent battery cells, and transferring the thermal energy from the inter-cell separator to a flow of coolant in thermal communication with the conductive inter-cell separator, thereby causing a phase change in the flow of coolant resulting in cooling of the plurality of battery cells. The thermal energy is then dissipated from the flow of coolant.