Compressible Graphene Foam Thermal Resistor for Runaway Prevention
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Solution Overview
Problem
Current thermal management systems for heat-generating devices, such as batteries, face challenges in efficiently managing heat across a range of operating conditions, particularly at high and low ambient temperatures, due to limited control over thermal conductance, leading to thermal runaway and performance degradation.
Innovation Solution
A variable thermal resistor system utilizing a reversibly-compressible, open-pore graphene foam that modulates heat transport between a heat source and a heat sink by controlling the degree of compression, enabling continuous tuning of thermal conductance and functioning as both a thermal switch and regulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional thermal switches or regulators are used, then thermal conductance can be modulated, but the tuning range is limited and continuous control is not achieved
Solution Approach 1:
The patent employs a compressible graphene foam structure that can be dynamically compressed to different degrees, enabling continuous tuning of thermal conductance. The foam's porous structure allows it to be compressed reversibly, providing dynamic control over heat transport pathways without requiring complex mechanical switching mechanisms.
Solution Approach 2:
The invention changes the physical state and density parameters of the graphene foam through compression. By varying the compression degree, the thermal conductance parameter is continuously adjusted, achieving a wide tuning range from highly conductive (compressed) to insulative (relaxed) states without altering the material composition.
2Ease of operation
If binary thermal switch states are used, then simple control is achieved, but continuous tuning of thermal conductance is not possible
Solution Approach 1:
The compressible graphene foam provides a dynamic transition between thermal states. Instead of abrupt binary switching, the foam allows gradual compression to achieve any intermediate thermal conductance value, maintaining operational simplicity while enabling continuous tuning through a single control parameter (compression degree).
3Volume of moving object
If existing solid-state thermal regulators are used, then compact design is achieved, but switching ratio and operating temperature window are limited
Solution Approach 1:
The patent uses graphene foam, a composite material with exceptional thermal properties. Graphene's high intrinsic thermal conductivity combined with the foam's porous structure enables both compact design and wide operating temperature window. The material maintains structural integrity and functional performance across extreme temperatures, from cryogenic to high-temperature environments.
4Reliability
If thermal management is not adequately controlled, then system simplicity is maintained, but thermal runaway and performance degradation occur
Solution Approach 1:
The compressible graphene foam provides self-regulating thermal management. When compressed, it automatically increases thermal conductance to dissipate heat; when relaxed, it provides insulation. This passive, self-service mechanism enhances thermal safety without requiring complex active control systems, sensors, or external power sources.
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 provides efficient thermal management with a large tuning range, maintaining optimal temperatures across varying conditions, and preventing thermal runaway, with a switching ratio of about 8.09 and a temperature window of 10°C, demonstrating reliability and rapid response times.
Implementation Method 1
modulating heat transport between a heat source and a heat sink based on a degree of compression of a graphene foam within the variable thermal resistors
Implementation Method 2
reversibly-compressible, open-pore graphene foam
Data Source
AI summary
Variable thermal resistors, systems, and methods suitable for modulating heat transport between a heat source and a heat sink based on a degree of compression of a reversibly-compressible, open-pore graphene foam within the variable thermal resistors. The variable thermal resistor is configured to controllably vary heat transport therethrough by controlling the degree of compression of the graphene foam.