Graphite Heat Spreader Assembly for Multi-Axis Heat Flux Control
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Solution Overview
Problem
Power electronic devices, particularly those made from silicon carbide, generate high heat flux due to a smaller device footprint, necessitating improved cooling solutions while maintaining a compact package size, and existing graphite layers do not provide uniform heat-spreading capabilities across multiple axes.
Innovation Solution
A heat spreader assembly comprising a metal layer encasing a single-layer graphite layer with multiple adjacent graphite pieces, each having different thermal conductivity axes to balance heat spreading across three dimensions, enhancing thermal conductivity and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single conventional graphite layer is used for heat spreading, then the structure remains simple, but the heat-spreading capability is non-uniform across different axes
Solution Approach 1:
The single graphite layer is segmented into multiple graphite pieces (first, second, and third graphite pieces) arranged in a layered configuration. Each piece has its thermal conductivity oriented in a different direction, allowing uniform heat spreading across all three spatial axes by combining the anisotropic heat conduction paths of individual segments.
Solution Approach 2:
Different regions of the heat spreader are assigned different thermal conductivity characteristics. The first graphite piece has high thermal conductivity in a first direction, the second graphite piece has high thermal conductivity in a second direction perpendicular to the first, and the third graphite piece has high thermal conductivity in a third direction. This local differentiation of thermal properties achieves uniform overall heat spreading.
2Area of stationary object
If silicon carbide is used for power electronic devices, then device footprint is reduced, but heat flux increases
Solution Approach 1:
The heat spreader utilizes three-dimensional stacking of graphite pieces with different thermal conductivity orientations to manage the increased heat flux. By arranging graphite pieces in multiple layers with perpendicular thermal conductivity directions, the system distributes heat conduction paths across three dimensions, effectively managing the high heat flux from the compact silicon carbide device.
3Volume of moving object
If compact package size is maintained, then device integration is improved, but cooling performance may be compromised
Solution Approach 1:
Multiple graphite pieces are nested within a single metal layer to form a compact heat spreader assembly. The first, second, and third graphite pieces are arranged in a nested configuration where smaller graphite pieces are positioned between larger ones, maximizing heat spreading capability within a minimal volume while maintaining compact package size.
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 solution provides enhanced heat flux distribution and cooling performance by balancing thermal conductivity across multiple axes, improving heat spreading and cooling efficiency in compact power electronic assemblies.
Implementation Method 1
The single-layer graphite layer includes three or more adjacent graphite pieces having high thermal conductivity along a thickness direction. At least one of the graphite pieces has low thermal conductivity along a first axis and the high thermal conductivity along a second axis.
Data Source
AI summary
Embodiments are directed to an electronic-cell assembly. The electronic-cell assembly includes an heat spreader and a power electronics device. The heat spreader includes a metal layer and a single-layer graphite layer. The metal layer encases the single-layer graphite layer and defines a power device recess in an outer surface of the metal layer. The single-layer graphite layer includes three or more adjacent graphite pieces having high thermal conductivity along a thickness direction. The power electronics device is disposed within the power device recess of the outer surface of the heat spreader. At least one of the graphite pieces has low thermal conductivity along a first axis and the high thermal conductivity along a second axis. The first axis and the second axis are perpendicular to the thickness direction. At least one of the graphite pieces has the high thermal conductivity along the first axis and the low thermal conductivity along the second axis.