Busbar Contact Lug Segmentation for Stress-Resistant Power Modules
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Solution Overview
Problem
Existing power module arrangements in motor vehicles face challenges in maintaining electrical conductivity over long service lives, particularly due to mechanical stress, temperature changes, and exposure to moisture and salt, which can lead to line breakage and reduced reliability.
Innovation Solution
A contact device comprising a busbar with contact connection lugs that are integrally bonded to external contact surfaces using a weld seam connection, with strategically placed through-openings to reduce mechanical and thermomechanical stresses, ensuring flexibility and maintaining electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welded connections are used to connect power modules to capacitors or electric machines, then electrical conductivity is achieved, but mechanical stress and vibrations can cause line breakage and reduce service life
Solution Approach 1:
The contact connection lug is segmented by introducing through-openings that divide the welded connection into multiple separate contact elements. This segmentation allows each contact element to independently accommodate mechanical stress and vibrations, preventing stress concentration and line breakage while maintaining electrical conductivity through parallel current paths.
Solution Approach 2:
The structural parameters of the contact connection lug are changed by adding through-openings, which transforms the solid continuous structure into a perforated structure. This parameter change reduces the lug's rigidity and allows it to flex under mechanical stress, thereby reducing stress-induced negative influencing factors while maintaining electrical conductivity.
2Reliability
If continuous welded connections are used in contact connection lugs, then electrical conductivity is maximized, but mechanical and thermomechanical stresses increase the risk of line breakage
Solution Approach 1:
The continuous welded connection is segmented into multiple discrete contact elements by through-openings. This creates multiple parallel electrical paths that collectively maintain conductivity while distributing mechanical stress across separate zones, preventing stress concentration and improving resistance to line breakage.
Solution Approach 2:
The through-openings act as pre-designed stress relief zones that cushion mechanical and thermomechanical stresses before they can propagate through the entire contact connection lug. This beforehand cushioning prevents stress concentration and reduces the risk of line breakage while preserving electrical conductivity through the remaining material.
3Reliability
If the contact connection lug is made rigid to ensure stable electrical contact, then contact stability is improved, but flexibility to accommodate stress is reduced
Solution Approach 1:
The structural parameters of the contact connection lug are modified by introducing through-openings, which changes the rigidity-flexibility balance. The lug maintains sufficient rigidity for stable electrical contact while gaining localized flexibility in the regions around the through-openings to accommodate mechanical stress and thermal expansion.
Solution Approach 2:
Different regions of the contact connection lug have different mechanical properties: the solid regions provide rigidity for stable electrical contact, while the regions around the through-openings provide flexibility to accommodate stress. This local quality differentiation resolves the contradiction between contact stability and stress adaptability.
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 contact device effectively reduces the impact of mechanical and thermomechanical stresses, enhancing the operational reliability and service life of power module arrangements by maintaining electrical conductivity and flexibility in the contact region.
Implementation Method 1
The electrical contacting of at least one contact connection lug with at least one external contact surface of one of the functional components is formed by means of an integral bond, in particular by means of a welded connection.
Implementation Method 2
the integral bond is interrupted by at least one through-opening in the contact connection lug such that at least two contact elements which exclusively have portions of the formed integral bond are formed on the contact connection lug
Data Source
AI summary
A contact device for electrically contacting at least two electrical functional components within a connection interface. The contact device includes at least one busbar which extends from a first to a second contact region. When the functional component is electrically contacted by different contact regions of the busbar, a current path can be formed within the busbar between the first and the second contact region. Each contact region has at least one contact connection lug for integral connection to an external contact surface. The electrical contacting of at least one contact connection lug with an external contact surface of one of the functional components is formed via an integral bond. The integral bond is interrupted by at least one through-opening in the contact connection lug such that at least two contact elements which exclusively have portions of the formed integral bond are formed on the contact connection lug.