Battery Electrode Tab Laser Welding to Reduce Weld Voids
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Solution Overview
Problem
Existing methods of laser welding electrode tabs to current collecting units in secondary batteries often result in voids or welding failure portions, leading to increased battery resistance.
Innovation Solution
The method involves sandwiching the electrode tab between a transparent material and the current collecting unit and applying laser to penetrate the transparent material, ensuring the electrode tab is stacked without gaps, using a pressure of 100 N or more, and employing a transparent material with a melting point of 800°C or more, such as crystallized glass, quartz glass, barium fluoride glass, or sapphire glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser welding is performed by stacking electrode tabs on current collecting unit without additional components, then the manufacturing process is simple, but voids are generated in the welded zone increasing battery resistance
Solution Approach 1:
A transparent pressing member is introduced as an intermediary component between the laser and the electrode tab/current collecting unit interface. This pressing member applies pressure during laser welding to eliminate voids while remaining transparent to laser radiation, thus improving welded zone quality without significantly complicating the manufacturing process
Solution Approach 2:
The transparency parameter of the pressing member is specifically selected to allow laser radiation to pass through while providing mechanical pressure. By changing the material parameter (transparency) of the pressing member, the system achieves both void elimination and process simplicity
2Manufacturing precision
If pressure is applied to sandwich electrode tab between transparent material and current collecting unit, then voids are reduced in welded zone, but manufacturing complexity increases
Solution Approach 1:
The transparent pressing member serves as a mediator that combines the functions of pressure application and laser transmission. This single component replaces complex multi-component pressing mechanisms, reducing manufacturing complexity while maintaining welded zone quality
Solution Approach 2:
By selecting materials with appropriate transparency parameters and mechanical properties, the pressing member achieves both void reduction through pressure and ease of manufacture through simple material selection rather than complex mechanical design
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 significantly reduces voids in the welded zone, thereby minimizing battery resistance and ensuring stable welding.
Implementation Method 1
applying laser to penetrate the transparent material
Implementation Method 2
laser is applied to penetrate the transparent material, thereby welding between the current collecting unit and the positive electrode tab
Implementation Method 3
welding between the electrode tab and the current collecting unit by sandwiching the electrode tab between a transparent material and the current collecting unit and then applying laser to penetrate the transparent material
Implementation Method 4
the transparent material has a melting point of 800° C. or more
Data Source
AI summary
Provided is a technique to reduce voids between an electrode tab and a current collecting unit in a portion where the electrode tab and the current collecting unit are welded. The secondary battery manufacturing method disclosed herein is a method of manufacturing a secondary battery including an electrode body having an electrode tab and a current collecting unit electrically connected to the electrode body. This method includes: welding between the electrode tab and the current collecting unit, by sandwiching the electrode tab between a transparent material and the current collecting unit and then applying laser to penetrate the transparent material.