Base Plate Inflection Point for Power Module Thermal Contact
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Solution Overview
Problem
Power semiconductor modules experience thermomechanical stress and increased heat transfer resistance due to differing heat expansion coefficients, leading to excessive temperatures and potential overheating when pressed against a heat sink.
Innovation Solution
A base plate with an uneven shaped first surface featuring at least one inflection point is designed to optimize heat transfer resistance by adjusting its geometry based on operating temperature and power loss, ensuring minimal distance variation between the base plate and heat sink, thereby maintaining optimal thermal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat base plate is used, then the structure is simple and easy to manufacture, but the heat transfer resistance increases due to distance variation under thermomechanical stress
Solution Approach 1:
The base plate incorporates a pre-defined curvature or uneven surface geometry on its lower side, transforming the flat surface into a curved or contoured surface. This curvature is specifically designed to compensate for the expected deflection under operating temperatures, ensuring that the base plate maintains optimal contact with the heat sink surface despite thermal expansion and mechanical stress.
Solution Approach 2:
The base plate is pre-formed with an uneven surface geometry during manufacturing, before the module is assembled and subjected to thermal stress. This preliminary shaping anticipates the future deflection that will occur during operation, so that when the module is heated and pressurized, the base plate naturally conforms to the heat sink surface, minimizing distance variation and heat transfer resistance.
2Reliability
If the base plate geometry is optimized for minimal heat transfer resistance, then thermal contact is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention modifies the geometric parameters of the base plate, specifically the surface profile, curvature radius, and elevation distribution, to optimize thermal contact. By carefully selecting and adjusting these geometric parameters during the design phase, the base plate achieves improved heat transfer characteristics while maintaining compatibility with standard manufacturing processes for pressed or injection-molded components.
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 effectively reduces heat transfer resistance and prevents overheating by optimizing the base plate's geometry to maintain minimal distance and ensure efficient cooling, even under varying power loss conditions.
Implementation Method 1
heat transfer resistance between the base plate and the heat sink
Implementation Method 2
thermomechanical stress occurs due to different heat expansion coefficients of different components of the module
Data Source
AI summary
A power semiconductor module is to be pressed to a heat sink with a first surface of a first side of a base plate. To reduce the heat transfer resistance between the base plate and the heat sink, the first surface has, at least in a state, when the power semiconductor module is not pressed against the heat sink, at least one inflection point.