Busbar Welding with Cut-Away Guide and U-Curved Link for Battery Cells
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Solution Overview
Problem
In battery systems, reliable and stable laser welding of busbars to electrode terminals is challenging due to dimensional errors, leading to gaps and unstable connections, which hinder efficient electrical connection.
Innovation Solution
The battery system incorporates a busbar with a cut-away portion and an exposure gap that guides the electrode terminal's protruding portion, allowing for fillet and penetration welds to ensure stable attachment, and includes a U-curved linking portion to absorb positional displacements, reducing stress and enhancing connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cut-away portion is provided in the busbar and electrode terminals are inserted into it, then the busbar can accommodate dimensional errors of battery cells, but gaps are generated between the busbar and electrode terminals due to varying intervals, making reliable laser welding difficult
Solution Approach 1:
A welding ring is introduced as an intermediary component between the busbar and electrode terminals. The welding ring fills the gap caused by dimensional variations and provides a stable interface for laser welding, ensuring reliable electrical connection while accommodating the adaptability requirement for varying intervals between electrode terminals
Solution Approach 2:
The welding ring is nested within the cut-away portion of the busbar and surrounds the electrode terminal, creating a hierarchical structure where the welding ring is positioned between the busbar and electrode terminal. This nested configuration allows the welding ring to mediate the connection while maintaining electrical conductivity and mechanical stability
2Reliability
If the inner shape of the welding ring is made equal to the outer shape of the electrode terminal to eliminate gaps, then welding stability improves, but the welding ring cannot be inserted smoothly into the electrode terminal
Solution Approach 1:
The welding ring is designed with non-uniform thickness, where the thickness varies at different angular positions. This local variation in thickness creates regions of different flexibility, allowing the welding ring to be inserted smoothly into the electrode terminal while maintaining sufficient rigidity for stable laser welding at the connection interface
3Ease of manufacture
If the welding ring is made thin to facilitate insertion, then insertion ease improves, but the welding ring lacks sufficient strength for reliable laser welding
Solution Approach 1:
The welding ring features non-uniform thickness distribution, with thinner sections for easy insertion and thicker sections at critical welding zones. This local quality variation ensures that the welding ring maintains sufficient strength and rigidity where needed for reliable laser welding, while remaining easy to insert in other regions
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 configuration enables reliable and stable laser welding of busbars to electrode terminals, even with dimensional errors, ensuring low resistance electrical connections and preventing detachment, while allowing for efficient detection and correction of positional gaps during the welding process.
Implementation Method 1
A boundary between the inserted electrode terminals and the busbar is irradiated with a laser beam, and both the electrode terminals and the busbar are melted and connected to each other at the boundary therebetween
Implementation Method 2
both the electrode terminals and the busbar are melted and connected to each other
Implementation Method 3
The busbar is welded by a fillet weld part that welds the inner edge of the cut-away portion to the welding surface of the electrode terminal, and a penetration weld part that welds the boundary with respect to the welding surface
Data Source
AI summary
A plurality of battery cells are connected by a busbar. Electrode terminals of the battery cells each include a protruding portion and a welding surface around the protruding portion. The busbar includes a welding plate portion being in surface-contact with the welding surface and having a cut-away portion for guiding the protruding portion, and an exposure gap that exposes the welding surface between the inner side of the cut-away portion and the protruding portion. The busbar is welded to the welding surface in a predetermined welding width (H) by both of a fillet weld part and a penetration welding portion such that the inner edge of the cut-away portion as the fillet weld part is welded to the welding surface, and the boundary between the busbar and the welding surface is welded by the penetration welding portion.