Secondary Battery Auxiliary Tab Structure for Bending-Durable 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 includes 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 welding speed and productivity are improved, but the welded portion becomes vulnerable to fatigue loading and may break during bending
Solution Approach 1:
The patent replaces ultrasonic welding (mechanical vibration-based) with laser welding (energy beam-based) for joining the auxiliary tab to the current collecting portion. This substitution eliminates the fatigue loading issues associated with ultrasonic welding while maintaining high productivity, as laser welding provides stronger, more durable welds resistant to bending and fatigue.
Solution Approach 2:
The patent changes the welding method from ultrasonic to laser welding, fundamentally altering the welding parameters and mechanism. Laser welding provides deeper penetration, higher strength, and better fatigue resistance compared to ultrasonic welding, thereby resolving the reliability issue while maintaining efficiency.
2Strength
If rigid material is used in auxiliary tab for structural strength, then strength and rigidity are improved, but the welded portion becomes prone to breakage during bending operations
Solution Approach 1:
The patent introduces a bending portion with flexible material in the auxiliary tab structure. This flexible portion is specifically designed to accommodate bending operations without causing weld breakage, while the rest of the auxiliary tab maintains its rigid structure for strength. The flexible portion acts as a buffer that absorbs bending stresses.
Solution Approach 2:
The auxiliary tab is segmented into different portions with different properties: a rigid portion for structural strength and a flexible bending portion for accommodating deformation. This segmentation allows each part to perform its specific function optimally without compromising the other.
3Reliability
If laser welding is applied to join auxiliary tab and current collecting portion, then weld strength and fatigue resistance are improved, but manufacturing complexity and process time increase
Solution Approach 1:
The patent replaces complex ultrasonic welding equipment and processes with laser welding technology. While laser welding requires precise positioning, it eliminates the need for complex mechanical pressure application and vibration generation systems, potentially simplifying the overall manufacturing setup while improving weld quality.
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
the current collecting connection portion welded to the current collecting portion by laser welding
Data Source
AI summary
The present invention relates to a secondary battery and a method for manufacturing same, and the technical problem to be solved is to prevent damage due to fatigue loading that may occur during ultrasonic welding between an electrode tab and an auxiliary tab, 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.