Cylindrical Battery Cell Collector Thickening for Laser Cap Welding
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Solution Overview
Problem
The existing cylindrical battery cell welding process faces challenges with a low process window and high defect rate due to the difficulty in welding the cap to the current collecting component using laser penetration welding.
Innovation Solution
A cylindrical battery cell design that includes a thickened portion on the current collecting component, increasing its thickness at the welding position with the cap, thereby reducing the risk of false welding or penetration during laser penetration welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser penetration welding is performed to connect the cap and the current collecting component, then welding connection is achieved, but the process window is low and defect rate is high due to thickness mismatch
Solution Approach 1:
The current collecting component is designed with a thickened portion at the welding location, creating local variation in thickness. This allows the welding area to have increased thickness (0.5-1.5mm) while the rest of the component maintains its original thin profile, enabling reliable laser penetration welding without affecting other areas of the component
Solution Approach 2:
The thickness parameter of the current collecting component is specifically modified at the welding position by adding a thickened portion. This parameter change creates optimal conditions for laser penetration welding by ensuring the laser can properly penetrate through the cap and into the current collecting component, establishing a reliable process window
2Strength
If the cap thickness is greater than the current collecting component thickness, then structural strength is improved, but welding penetration or false welding occurs due to thickness mismatch
Solution Approach 1:
Instead of uniformly increasing the current collecting component thickness, a localized thickened portion is added only at the welding position. This maintains the overall lightweight design while providing sufficient thickness (0.5-1.5mm) at the critical welding area to prevent welding penetration and false welding defects
3Reliability
If welding is performed to connect the cap and current collecting component, then electrical connection is established, but thermal impact affects the electrode assembly
Solution Approach 1:
The thickened portion acts as a thermal buffer or intermediary layer between the welding zone and the electrode assembly. Its increased thickness provides thermal mass that absorbs and dissipates welding heat, reducing the thermal impact transmitted to the electrode assembly while maintaining effective electrical connection
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
The design enhances the welding quality by reducing the difficulty of welding and the defect rate, while also minimizing thermal impact on the electrode assembly and improving adhesion between the cap and the current collecting component.
Implementation Method 1
when laser penetration welding is performed to connect the cap and the current collecting component
Implementation Method 2
minimizing thermal impact on the electrode assembly
Data Source
AI summary
A cylindrical battery cell including a housing, an electrode assembly, a cap and a current collecting component is provided. The housing includes an end wall and a side wall surrounding the end wall. An opening is formed on one side of the side wall facing away from the end wall. The electrode assembly is disposed in the housing, and a first tab is provided on one side of the electrode assembly facing the opening. The cap is disposed on a side where the opening located, and is welded and connected to the side wall to seal the opening. The current collecting component is disposed on one side of the electrode assembly facing the opening, and the current collecting component is welded and connected to the first tab. The current collecting component includes a current collecting body and a thickened portion welded and connected to the cap.