Spring Busbar Contacts for Stress-Free Inverter Module Joining
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Solution Overview
Problem
Existing power electronic devices face mechanical stresses and crack formations during assembly due to uncontrolled bending of busbars during laser welding, leading to potential material flaking and moisture ingress, and require costly specialized tools for joining.
Innovation Solution
The use of spring contacts with convex curved end regions for busbar formation between power electronic components, allowing for automatic tolerance balancing and reliable line contact creation without additional tools, and enabling secure electrical connections through welding, soldering, or conductive gluing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If busbars are bent to ensure gap-free contact during laser welding, then welding reliability is improved, but mechanical stresses and crack formations occur in the encapsulation and casting compound
Solution Approach 1:
The busbar is pre-formed with a curved end region before the joining process, which automatically compensates for tolerance deviations during assembly. This preliminary shaping eliminates the need for additional bending operations during welding, preventing stress-induced crack formations while ensuring reliable gap-free contact.
2Manufacturing precision
If specialized tools are used for the joining process, then joining precision is improved, but device complexity and cost increase
Solution Approach 1:
The busbar's own curved geometry serves as the adjustment mechanism, automatically compensating for tolerance deviations through its elastic deformation capability. This self-adjusting feature eliminates the need for external specialized tools, reducing device complexity and cost while maintaining high joining precision.
Solution Approach 2:
The busbar end region is designed with dynamic elasticity, allowing it to deform and adapt to tolerance variations during the joining process. This dynamic behavior enables precise alignment and gap-free contact without requiring complex rigid positioning tools.
3Ease of manufacture
If rigid busbars are used for connection, then manufacturing simplicity is improved, but tolerance compensation capability deteriorates
Solution Approach 1:
Only the end region of the busbar is given elastic properties through curved geometry, while the rest of the busbar remains rigid for structural stability. This localized elasticity provides tolerance compensation capability without compromising overall manufacturing simplicity and structural integrity.
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
This solution minimizes mechanical stresses, prevents crack formations, ensures reliable electrical connections over all tolerance levels, and eliminates the need for specialized tools, enhancing the durability and production efficiency of power electronic devices.
Implementation Method 1
at least one of the two contact tabs, the first contact tab and/or the second contact tab, is designed as a spring contact and an end region of the spring contact presses against the other respective contact tab
Implementation Method 2
an end region of the spring contact presses against the other respective contact tab when forming the at least one busbar and forms a line contact between the first contact tab and the second corresponding contact tab. The end region of the spring contact is curved convex with respect to the other respective contact tab.
Implementation Method 3
The first contact tab and the second contact tab are connected to each other permanently along the line contact
Implementation Method 4
The first contact tab and the second contact tab comprise a weld connection along the line contact
Implementation Method 5
The first contact tab and the second contact tab comprise an electrically conductive glue connection along the line contact
Data Source
AI summary
The disclosure relates to power electronic devices with busbars and a method for their fabrication. In particular, the disclosure relates to the connection of semiconductor power modules and intermediate circuit capacitor in a commutation cell of an inverter of an electrically powered motor vehicle.