Cement Encapsulation for High-Temperature Power Electronics
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Solution Overview
Problem
Current encapsulation materials for power electronics and sensor systems are limited to a temperature range of below 200°C, restricting the operating range of modern power semiconductors like SiC, and lack improved thermal protection against environmental influences.
Innovation Solution
An electrical device with an encapsulation compound comprising a cement mass containing particles and fibers with higher thermal conductivity than the cement, which increases the thermal conductivity of the encapsulating mass, allowing for efficient heat dissipation and extended operating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional encapsulation materials (epoxy compounds, silicon masses) are used, then the encapsulation provides protection against environmental influences, but the operating temperature range is limited to below 200°C
Solution Approach 1:
The patent uses a composite encapsulation material consisting of cement compound as the base matrix combined with inorganic fibers (such as alumina, silica, or zirconia) as reinforcement. This composite structure provides both the high temperature resistance required for operating ranges up to 300-350°C and the protective properties against environmental influences. The inorganic fibers enhance the thermal stability and mechanical strength of the cement-based encapsulation, enabling it to withstand extreme temperatures while maintaining protective functionality.
Solution Approach 2:
The invention fundamentally changes the material composition parameters of the encapsulation by replacing organic polymer-based materials (epoxy, silicon) with inorganic cement-based materials. This parameter change in the chemical composition enables the encapsulation to withstand significantly higher temperatures. The cement compound undergoes hydraulic setting and forms a stable inorganic matrix that maintains its structural integrity and protective properties at temperatures where traditional encapsulation materials would degrade.
2Temperature
If the operating temperature range is extended to 300-350°C, then modern power semiconductors can operate beyond 200°C, but the thermal management requirements become more critical
Solution Approach 1:
The composite structure of cement compound with inorganic fibers creates a material with optimized thermal properties. The inorganic fibers (alumina, silica, zirconia) have high thermal stability and contribute to heat dissipation pathways within the encapsulation. This composite approach allows the encapsulation to handle the increased thermal loads generated by power semiconductors operating at 300-350°C, transforming the thermal management challenge into an opportunity for enhanced device performance.
Solution Approach 2:
The patent replaces the need for complex external thermal management systems with an intrinsically thermally stable encapsulation material. By using cement compound with inorganic fibers, the encapsulation itself becomes part of the thermal management solution, providing passive heat dissipation and thermal stability without requiring additional active cooling mechanisms, thereby reducing energy losses.
3Loss of energy
If cement compound is used as encapsulation material, then thermal conductivity can be significantly increased, but the material selection and processing complexity increases
Solution Approach 1:
The cement-based encapsulation combined with inorganic fibers creates a composite material that naturally provides enhanced thermal conductivity. The inorganic fiber network within the cement matrix establishes efficient heat transfer pathways, improving thermal management. This composite approach simplifies the overall system design by integrating thermal management functionality directly into the encapsulation material, reducing the need for separate thermal management components and associated processing steps.
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 significantly enhances thermal conductivity and heat dissipation, enabling higher operating temperatures, increased efficiency, and reduced installation space for electrical devices, while maintaining protection against environmental influences.
Implementation Method 1
The cement hardens hydraulically, i.e. a chemical reaction with water takes place to form stable, insoluble compounds. In this case, the cement can be in the form of a finely ground powder at the start of the process or before hydration, which reacts with water or added water to form hydrates, solidifies and hardens.
Implementation Method 2
An electrical device with an encapsulation compound comprising a cement mass containing particles and fibers with higher thermal conductivity than the cement, which increases the thermal conductivity of the encapsulating mass, allowing for efficient heat dissipation and extended operating temperatures.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an electrical device (10) comprising an electrical component (12) that is at least partially covered by a covering material (20) that comprises a cement material (22). Said covering material (20) also comprises particles (24a, 24b) having a first material and fibres (26) having a second material, wherein said first material and second material possess a higher coefficient of thermal conductivity than the cement of the cement material (22).