Busbar Laser Weld Pattern for Low-Heat Battery Connections
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Solution Overview
Problem
Existing battery module manufacturing processes face challenges in minimizing the size and weight of busbar assemblies while reducing electrical resistance and avoiding faulty connections, which can lead to module malfunction and increased costs due to rework or scrapping.
Innovation Solution
A method of laser welding a lattice portion of a busbar assembly to a terminal collection plate, controlling the welding process to manage heat distribution and avoid localized heating, which allows for precise electrical connections and reduced distortion, using a pattern that spaces out weld points to mitigate heat input and maintain a flat busbar assembly shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple weld points are used to join the busbar assembly, then the electrical connection reliability is improved, but the localized heating and distortion increase
Solution Approach 1:
The welding process uses periodic action by implementing a skip welding pattern where weld points are spaced at intervals rather than continuous welding. The laser welds selected tabs at discrete locations (first, second, third weld points) with gaps between them, allowing heat to dissipate and preventing excessive localized heating while still achieving reliable electrical connections through multiple distributed weld points.
2Weight of stationary object
If the busbar assembly size is reduced, then the vehicle weight and packaging volume are minimized, but the manufacturing precision and welding quality become more difficult to maintain
Solution Approach 1:
The welding process applies segmentation by dividing the welding operation into discrete, separated weld points rather than continuous welding. The laser welds specific tabs at defined locations (first weld point, second weld point, third weld point) with controlled spacing, enabling precise heat management and maintaining welding quality even in reduced-size busbar assemblies. This segmented approach allows each weld point to be independently controlled for optimal quality.
3Productivity
If continuous welding is performed across the busbar assembly, then the manufacturing speed is improved, but the heat input and distortion increase
Solution Approach 1:
The welding process implements periodic action through skip welding, where the laser performs welding at discrete intervals (first weld point, then after moving to second weld point, then third weld point) rather than continuous welding. This periodic welding pattern maintains manufacturing efficiency by automating the process while preventing excessive heat accumulation and distortion by allowing thermal dissipation between weld points.
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 approach results in a more efficient, repeatable, and reliable manufacturing process that minimizes electrical resistance and maintains the busbar assembly's intended shape, enhancing the reliability and performance of battery modules by ensuring consistent and high-quality electrical connections.
Implementation Method 1
A method of laser welding a lattice portion of a busbar assembly, the lattice portion comprising copper, to a terminal collection plate of the busbar assembly, the terminal collection plate comprising aluminium
Implementation Method 2
controlling a laser welding system to perform a welding process to weld the lattice portion and the terminal collection plate together at a plurality of weld points
Implementation Method 3
Between the first and a subsequent weld point, the busbar assembly at the subsequent weld point may be at a lower temperature than the busbar at the first position (or another prior welded position) due to the welding of the first (or prior) point causing localised heating of the busbar at the first (or prior) position
Implementation Method 4
Welding the lattice portion and the terminal collection plate together at a first weld point may cause a temperature gradient having a localised high temperature region at the first weld point and a low temperature region elsewhere
Data Source
AI summary
The present disclosure relates to busbar assemblies (206) and battery modules (200). A method comprises welding a lattice portion (302) and a terminal collection plate (304) together by welding a first weld point (402), welding at a second weld point (404), and welding at a third point (406) between the first and the second weld points.