Pyrolytic Graphite Inserts in Power Card Baseplates
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Solution Overview
Problem
High-power DC/DC converters face thermal challenges due to significant heat generation, leading to increased cost, weight, and complexity, as standard aluminum baseplates have thermal limitations, necessitating the use of additional heat sinks and increased size and weight to manage heat dissipation effectively.
Innovation Solution
Incorporating annealed pyrolytic graphite (PG) inserts into the baseplate of a power card, which enhances thermal conductivity while maintaining electrical conductivity, allowing for efficient heat dissipation without the need for separate heat sinks, thereby reducing temperature rise and improving overall performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aluminum baseplate is used for heat dissipation, then thermal conductivity is improved compared to dielectric material, but thermal limitations still exist requiring additional heat sinks and increasing device size and weight
Solution Approach 1:
The patent uses a composite structure combining aluminum baseplate with pyrolytic graphite inserts. The graphite inserts have superior thermal conductivity in the plane of the insert, working synergistically with the aluminum baseplate to achieve better heat dissipation than aluminum alone, while avoiding the need for additional large heat sinks that would increase weight.
Solution Approach 2:
The pyrolytic graphite inserts are strategically positioned at locations where heat-generating components are mounted. This local enhancement of thermal conductivity directly at the heat source areas provides targeted heat dissipation improvement without requiring uniform thickening of the entire baseplate or addition of large external heat sinks.
2Temperature
If aluminum baseplate is used for heat dissipation, then thermal conductivity is improved compared to dielectric material, but device size and complexity increase due to additional heat sinks
Solution Approach 1:
The patent merges the baseplate structure with heat dissipation functionality by embedding pyrolytic graphite inserts directly within the aluminum baseplate. This integration eliminates the need for separate additional heat sinks and simplifies the overall structure, as the baseplate itself becomes the primary heat dissipation path.
Solution Approach 2:
The composite of aluminum and pyrolytic graphite creates a material system with enhanced thermal properties that eliminates the need for complex multi-component heat dissipation systems. The graphite-aluminum composite provides sufficient heat dissipation capability within the baseplate structure itself.
3Temperature
If pyrolytic graphite inserts are added to increase thermal conductivity, then temperature rise is reduced, but cost increases
Solution Approach 1:
Rather than using pyrolytic graphite throughout the entire baseplate, the patent employs graphite inserts only at specific locations where heat-generating components are mounted. This localized approach reduces the total amount of expensive graphite material required while still achieving significant temperature reduction at the critical heat dissipation points.
Solution Approach 2:
The patent optimizes the parameters of the graphite inserts including their size, shape, and positioning to achieve the necessary thermal performance at minimum cost. By carefully controlling the insert dimensions and locations, the design achieves effective heat dissipation with reduced material usage compared to full-graphite or larger-insert designs.
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 use of PG inserts in the power card baseplate effectively reduces temperature rise by up to 30°C, enabling the design of high-power DC/DC converters with reduced cost, weight, and complexity, while maintaining thermal performance, thus improving reliability and meeting future power demands.
Implementation Method 1
The first layer is a material that is both thermally and electrically conductive... the insert can dissipate heat generated by the circuit card assembly
Data Source
AI summary
A printed circuit board (PCB) assembly is provided. The PCB assembly is adapted for mounting at least one heat-generating electrical device and providing integrated heat dissipating capability to dissipate heat generated by the electrical device. The PCB assembly has a top surface and a bottom surface and comprises a signal carrying layer and an insert of pyrolytic graphite (PG). The signal carrying layer, disposed between the top surface and the bottom surface, comprises a material that is both thermally conductive and electrically conductive (such as at least one of aluminum, copper, and silver and alloys thereof) and has at least a portion lying in a first plane. The insert of PG is disposed within at least a portion of the first plane of the signal carrying layer, is in thermal contact with the signal carrying layer, and is constructed and arranged to have its greatest electrical conductivity in the first plane. Optionally, a conductive via can be formed in portions of the signal carrying layer not occupied by the insert of PG, where the conductive via operably couples a first side of the signal carrying layer to a second side of the signal carrying layer.