Laser Welded Bus Bar on Power Circuit Board
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Solution Overview
Problem
Existing methods for manufacturing power circuit boards face limitations in connecting bus bars to conductive tracks, particularly in accommodating varying dimensions and ensuring reliable high-current transmission, which is challenging especially in the automotive field.
Innovation Solution
A process involving laser welding of bus bars to conductive tracks on power circuit boards, where the bus bar thickness at the weld spot is less than twice the track thickness, allowing for precise and reliable connections, and optionally connecting additional bus bars to facilitate high-current conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the width and thickness of conductive tracks are increased to pass high currents, then the current carrying capacity is improved, but the circuit size becomes incompatible with required dimensions
Solution Approach 1:
The patent transitions from two-dimensional track width/thickness adjustments to three-dimensional bus bar structures with varying thickness profiles. By introducing vertical dimension control through thickness restrictions at weld spots, the solution achieves high current capacity without increasing planar circuit board area.
Solution Approach 2:
The bus bar is designed with non-uniform thickness distribution, featuring restricted thickness zones at welding locations and larger thickness zones for current conduction. This local quality variation allows the bus bar to optimize both welding performance and current carrying capacity independently.
2Strength
If conventional connection methods (screwing, brazing, press-fitting) are used to connect bus bars to tracks, then mechanical strength is improved, but the process complexity and time increase
Solution Approach 1:
The patent replaces mechanical connection methods (screwing, press-fitting, brazing) with laser welding technology. This substitution eliminates complex mechanical assembly processes while achieving strong, reliable electrical and mechanical connections through direct metallurgical bonding.
Solution Approach 2:
The invention changes the connection process parameters by using laser welding with controlled energy input. By adjusting laser power, speed, and focus position, the process achieves optimal weld quality without the complexity of mechanical fastening systems.
3Productivity
If laser welding is used to connect bus bars to conductive tracks, then production speed and precision are improved, but the bus bar thickness must be restricted to less than two times the track thickness
Solution Approach 1:
The bus bar is segmented into functional zones: welding zones with restricted thickness for laser welding compatibility, and conduction zones with larger thickness for current carrying. This segmentation allows the bus bar to meet both welding process requirements and electrical performance requirements.
Solution Approach 2:
The thickness restriction zones are built into the bus bar design before welding. This preliminary geometric preparation ensures that the bus bar is pre-configured for successful laser welding, eliminating the need for post-manufacturing thickness reduction operations.
4Quantity of substance
If a single thick bus bar is used for high current transmission, then current carrying capacity is improved, but reliable laser welding becomes difficult to achieve
Solution Approach 1:
The bus bar features localized thickness variations with restricted thickness zones precisely at welding positions. This local quality control ensures optimal laser welding conditions at joint locations while maintaining sufficient overall thickness for high current transmission capability.
Solution Approach 2:
The invention changes the geometric parameters of the bus bar by introducing controlled thickness restrictions. This parameter modification enables the bus bar to satisfy both the high current transmission requirement (adequate overall cross-section) and the reliable laser welding requirement (controlled joint area geometry).
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 process enables efficient, flexible, and economical industrial implementation, accommodating various material thicknesses and enabling high production rates with reliable electrical connections suitable for high-power applications.
Implementation Method 1
the bus bar and the conductive track are laser welded at one or more weld spots
Data Source
AI summary
The invention relates to a process for manufacturing a power circuit board in which, on the one hand, a printed circuit board including an insulating substrate and a conductive track on one of the sides of the substrate, and on the other hand, a bus bar element, are provided. The bus bar element is welded to the conductive track using a laser. In order to make it possible to produce the weld by laser welding, even with a relatively thick bus bar, the welding is carried out in a zone that is thinner relative to the maximum thickness of the bus bar. Thus, a printed circuit board is obtained with a bus bar having a thick zone for conducting high currents and a thinner zone in order to allow the bus bar to be welded to the conductive track by laser welding.