Auxiliary Tab Structure for Bend-Resistant Battery Laser Welding
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Solution Overview
Problem
Secondary batteries face issues with damage due to fatigue loading during ultrasonic welding between electrode tabs and auxiliary tabs, and the welded portions can break during bending.
Innovation Solution
The secondary battery incorporates an auxiliary tab as a single plate strongly laser-welded with a current collecting portion, using a flexible rigid material in the auxiliary tab to prevent breakage during bending. The laser welding involves a linear and circular welding portion to ensure strong and durable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic welding is used to join electrode tab and auxiliary tab, then the welding process is simple and fast, but the welded portion is susceptible to fatigue loading damage and breakage during bending
Solution Approach 1:
The patent replaces ultrasonic welding (mechanical vibration-based) with laser welding (optical/thermal-based) to join the auxiliary tab to the current collecting portion. This substitution eliminates the fatigue loading issues associated with ultrasonic welding while maintaining efficient joining, as laser welding creates a more robust weld seam resistant to bending and fatigue stresses
Solution Approach 2:
The auxiliary tab is constructed using a composite structure with a rigid base material (aluminum or copper) and a flexible material layer. This composite construction allows the welded portion to withstand bending stresses while maintaining joint integrity, solving the breakage problem during bending operations
2Strength
If the auxiliary tab is made completely rigid, then the welding strength is high, but the welded portion breaks during bending operations
Solution Approach 1:
The auxiliary tab employs local quality by having different regions with different properties: the base material (aluminum or copper) provides rigidity and welding strength, while the flexible material layer provides bendability. This localized differentiation allows the structure to maintain strength where needed while accommodating bending without breakage
Solution Approach 2:
The auxiliary tab uses a composite material structure combining rigid aluminum or copper with flexible material. This composite construction enables the welded portion to resist breakage during bending while maintaining adequate welding strength, as the rigid component handles the welding load and the flexible component accommodates bending stresses
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 effectively prevents damage from fatigue loading and breakage during bending, ensuring the reliability and longevity of the secondary battery.
Implementation Method 1
an auxiliary tab as a single plate and a current collecting portion are strongly laser-welded
Data Source
AI summary
The present invention relates to a secondary battery and a method for manufacturing same, by strongly laser welding between the auxiliary tab and a current collecting portion of a single plate. To this end, disclosed is a secondary battery and a method for manufacturing same, wherein the secondary battery comprises: an electrode assembly having an electrode tab; an auxiliary tab which is a metal single plate mechanically and electrically coupled to the electrode tab; and a current collecting portion which is mechanically and electrically coupled to the auxiliary tab, wherein the auxiliary tab comprises: a tab connection portion welded to the electrode tab; a current collecting connection portion welded to the current collecting portion and disposed parallel to the tab connection portion; and a bending portion which connects between the tab connection portion and the current collecting connection portion and surrounds one side of the current collecting portion.