Aircraft Battery Thermal Circuit for Cold Soak Capacity Loss
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Solution Overview
Problem
Aircraft batteries face capacity loss and reduced vehicle range due to cold soak conditions, especially during cruise at high altitudes or in uncontrolled environments, where conventional thermal management techniques are insufficient.
Innovation Solution
A battery thermal management system incorporating a liquid heat exchange circuit, air heat exchange circuit, and a liquid-air heat exchanger, with a coolant pump and flow restrictors to regulate heat transfer, along with a method to control temperature by varying flow areas and using a bypass valve to maintain battery warmth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If batteries are exposed to cold soak conditions during cruise, then vehicle range is reduced and capacity is lost, but adding thermal management systems increases device complexity
Solution Approach 1:
The patent combines the liquid heat exchange circuit and air heat exchange circuit into a single thermal management system with a common controller, integrating multiple thermal management functions into one unified system rather than separate independent systems
Solution Approach 2:
The thermal management system performs multiple functions including heating batteries during cold soak, cooling batteries during charging/discharging, and adapting to different flight phases (cruise, climb, descent), making a single system that handles various thermal management needs
2Temperature
If a liquid heat exchange circuit is used to prevent cold soak, then battery temperature is maintained, but system complexity and fluid management requirements increase
Solution Approach 1:
The patent introduces a thermal fluid as an intermediary substance that transfers heat between the batteries and the heat exchange circuits, enabling indirect thermal management rather than direct contact heating or cooling
Solution Approach 2:
The system uses a liquid-based heat exchange circuit with a coolant pump to circulate thermal fluid through channels in contact with batteries, applying hydraulic principles for thermal management
3Measurement precision
If flow restrictors are added to regulate heat transfer, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent controls heat transfer by changing the flow rate parameter of the thermal fluid through flow restrictors and pump speed control, adjusting physical parameters to achieve precise temperature management
4Device complexity
If batteries are located in unclimate-controlled compartments, then aircraft structure is simplified, but batteries experience cold soak and capacity loss
Solution Approach 1:
The thermal management system allows batteries to self-regulate their temperature by using waste heat from the aircraft's air conditioning system or engine exhaust when available, and activating heating only when necessary, reducing the need for dedicated climate-controlled compartments
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 effectively prevents capacity loss and reduces recharging time, maintaining vehicle range by efficiently managing battery temperature during cold soak conditions.
Implementation Method 1
a liquid-air heat exchanger. The liquid-air heat exchanger is positioned on the liquid heat exchange circuit and the air heat exchange circuit to exchange heat therebetween
Implementation Method 2
The system includes a coolant pump fluidically connected to the liquid heat exchange circuit
Implementation Method 3
The system includes at least one flow restrictor positioned in the liquid heat exchange circuit
Implementation Method 4
The system can include a battery heat exchanger positioned on the liquid heat exchange circuit
Data Source
AI summary
A battery thermal management system for an air vehicle includes a liquid heat exchange circuit, an air heat exchange circuit, and a liquid-air heat exchanger. The liquid-air heat exchanger is positioned on the liquid heat exchange circuit and the air heat exchange circuit to exchange heat therebetween. The system includes a coolant pump fluidically connected to the liquid heat exchange circuit, a flow restrictor positioned in the liquid heat exchange circuit, and a battery in thermal communication with the liquid heat exchange circuit. A method for controlling a thermal management system for an air vehicle includes sensing a temperature of a battery with a temperature sensor, varying a flow area of a flow path through a liquid heat exchange circuit with the flow restrictor if the temperature is below a pre-determined threshold, and operating a pump to provide heating to the battery if the temperature is below the pre-determined threshold.