Thermal Interface Material Sheet With Embedded Sensors
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Solution Overview
Problem
Existing methods for measuring chip temperature in power electronic modules are laborious, expensive, and often damage the modules, while also being unsuitable for modules without a base plate or those with complex cooling systems, and do not account for base plate deformation which can reduce heat transfer and lead to intolerable chip temperatures.
Innovation Solution
A thermal interface material sheet with integrated thin film sensors, such as PVD grown resistive temperature sensors or piezo resistive strain gauges, that can measure temperature and pressure without affecting heat transfer, allowing for accurate monitoring of chip conditions without damaging the module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spring loaded thermocouples are used to measure case temperature, then temperature measurement is achieved, but the measurement is inaccurate when thermal interface material is present and the method is not suitable for modules without base plates or with complex cooling systems
Solution Approach 1:
The patent combines the temperature sensor with the thermal interface material itself, creating an integrated solution where the TIM sheet contains embedded temperature sensors. This merging eliminates the need for separate spring-loaded thermocouples and allows the same structure to serve both as thermal interface material and as a sensing element, thereby improving both measurement accuracy and adaptability across different module types.
Solution Approach 2:
The thermal interface material sheet is designed to be universally applicable across different power electronic module types, including those with and without base plates, and various cooling system configurations. The integrated sensors are positioned to measure temperatures at multiple locations regardless of the specific module or cooling system architecture, making the solution adaptable and versatile.
2Measurement precision
If holes are drilled to place thermocouples in contact with the base plate, then temperature measurement is possible, but the power electronic module is damaged and electrical wires affect electrical operation
Solution Approach 1:
The patent extracts the temperature sensing function from the traditional thermocouple approach and integrates it directly into the thermal interface material sheet. This eliminates the need to drill holes into the base plate or module, thereby preserving module integrity and avoiding interference with electrical operations while still enabling accurate temperature measurement at the interface.
Solution Approach 2:
The thermal interface material sheet acts as an intermediary between the power electronic module and the cooling device, and simultaneously serves as the medium for temperature sensing. By embedding sensors within this intermediary layer, the patent achieves temperature measurement without direct contact that would require drilling or inserting wires into the module, thus maintaining reliability.
3Measurement precision
If solid thermal interface materials are used for measurement, then the material should be removed from measurement locations, but this complicates the measurement process and may affect thermal performance
Solution Approach 1:
The patent merges the temperature sensing function with the solid thermal interface material by embedding sensors within the TIM sheet structure. This integration allows the material to remain in place during measurement without requiring removal or special handling, simplifying the measurement process while maintaining both thermal performance and measurement accuracy.
4Stability of the object's composition
If base plate deformation is allowed to occur during operation, then the module can withstand thermal cycling and power cycling, but heat transfer from module to heatsink is reduced and chip temperatures rise to intolerable values
Solution Approach 1:
The patent implements preliminary monitoring by embedding temperature sensors in the thermal interface material sheet before the module operates. This allows continuous monitoring of temperatures at the interface and enables detection of conditions that precede intolerable chip temperatures, allowing for preventive action before damage occurs.
Solution Approach 2:
The integrated temperature sensors provide real-time feedback on the thermal conditions at the interface between the module and heatsink. This feedback mechanism allows monitoring of the effects of base plate deformation on heat transfer, enabling detection of when deformation is causing temperatures to rise to dangerous levels.
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
Enables accurate and non-invasive temperature and pressure monitoring within power electronic modules, maintaining heat transfer efficiency and preventing damage from intolerable chip temperatures, even in modules with deformation, by using a carbon-based sheet with insulating layers and sensors that can be used with various cooling devices without modification.
Implementation Method 1
PVD grown resistive temperature sensors
Implementation Method 2
piezo resistive strain gauges
Implementation Method 3
thermal interface material sheet disposed between the cooling device and the power electronic module
Implementation Method 4
PVD grown resistive temperature sensors
Data Source
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AI summary
A thermal interface material sheet, method of manufacturing a thermal interface material sheet and an electrical device. The thermal interface material sheet is to be disposed between a heat generating electrical component and a cooling device, the thermal interface material sheet comprising at least one thin film sensor and electrical conductors connected to the at least one thin film sensor for measuring a property related to the heat generating electrical component.