Power Module Expansion Joint Layout for Stress and Flashover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power modules with metal-ceramic substrates face thermomechanical stresses due to differing thermal expansion coefficients, leading to bending and potential electrical flashover issues.
Innovation Solution
A power module design featuring a ceramic layer with interruptions acting as expansion joints, flanked by metal-free regions, and symmetrical metal layers to mitigate thermomechanical stresses and prevent electrical flashover, while allowing for increased conductor track density and space-efficient design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous metal layer is used on the ceramic substrate, then electrical conductivity and component connectivity are improved, but the risk of electrical flashover between adjacent metal sections increases
Solution Approach 1:
The continuous metal layer is segmented into separate metal sections by the interruption in the ceramic layer. This segmentation physically isolates adjacent metal sections, preventing electrical flashover while maintaining connectivity within each section. The metal layer is divided into discrete regions that are electrically isolated from one another by the metal-free expansion joint region.
Solution Approach 2:
The metal-free region acts as an intermediary barrier between adjacent metal sections. This intermediate zone, created by the ceramic interruption, provides electrical isolation and prevents direct electrical discharge between metal sections, thereby eliminating flashover risk while allowing thermal expansion accommodation.
2Productivity
If metal sections are placed close to interruptions to maximize space utilization, then conductor track density is improved, but the risk of electrical flashover between metal layers increases
Solution Approach 1:
The ceramic layer is segmented with interruptions that create metal-free regions, physically separating metal sections even when they are positioned closely together. This segmentation allows high conductor track density while maintaining electrical isolation, as the interruption breaks the continuous ceramic path that would otherwise allow flashover.
Solution Approach 2:
The metal-free expansion joint region serves as an intermediary protective zone between metal sections. This intermediate region, devoid of conductive material, provides a safety margin that prevents electrical flashover even when metal sections are positioned at minimal distances to maximize space utilization.
3Strength
If a single continuous ceramic layer is used, then structural integrity is improved, but thermomechanical stresses cause bending and potential failure
Solution Approach 1:
The continuous ceramic layer is segmented into separate ceramic sections by introducing interruptions. These interruptions create expansion joints that allow independent movement of adjacent ceramic sections under thermal stress, preventing the accumulation of thermomechanical stresses that would otherwise cause bending and potential failure of a continuous ceramic structure.
4Ease of manufacture
If metal layers are made asymmetrical to optimize component placement, then ease of manufacture is improved, but bending due to thermomechanical stresses worsens
Solution Approach 1:
The ceramic layer is segmented with interruptions positioned to create metal-free regions that serve as expansion joints. This segmentation allows the metal layers to be asymmetrical for optimized component placement while the interruptions prevent bending by allowing differential thermal expansion, thus decoupling the symmetry requirement from the manufacturing flexibility.
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 bending and electrical flashover risks, enhances thermal management, and enables higher conductor track densities on the component side, improving the structural integrity and operational reliability of power modules.
Implementation Method 1
Due to the different thermal expansion coefficients of the metal in the metal layer on the one hand and the ceramic in the ceramic layer on the other hand, thermomechanical stresses regularly arise, which can even lead to bending of the metal-ceramic substrate
Implementation Method 2
an insulation layer, which is preferably made of a ceramic
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2F
AI summary
The invention relates to a power module (1) for electrical components (19), said module comprising: - a ceramic layer (30), a primary metal layer (10) and a secondary metal layer (20), the primary metal layer (10) and the secondary metal layer (20) being provided on opposite sides of the ceramic layer (30), the ceramic layer (30) having a first ceramic portion (31) and a second ceramic portion (32) spaced apart from the first ceramic portion (31) by a gap (5), and a metal-free region being formed below and above the gap (5) which serves as an expansion joint.