Electrode Assembly Foreign Particle Prevention
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Solution Overview
Problem
Rechargeable lithium batteries are prone to short circuits and explosions due to foreign particles generated during the ultrasonic welding process, which can cause safety issues and manufacturing challenges.
Innovation Solution
Incorporating a foreign particle preventing member, such as an adhesive tape or insulation resin, along the boundaries of the electrode uncoated regions to prevent particles from entering the electrode assembly and causing short circuits, which are wound together with the electrodes and separator to minimize particle movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic welding process is used to integrate overlapped uncoated regions, then manufacturing efficiency is improved, but foreign particles are generated and may cause short circuits
Solution Approach 1:
An insulating member is introduced as an intermediary component between the electrodes and the welding horn during ultrasonic welding. This mediator prevents direct contact between the horn and the electrode uncoated regions, thereby preventing metal particles from being generated and entering the electrode assembly while still allowing the welding process to proceed effectively
Solution Approach 2:
The insulating member is placed in advance on the electrode uncoated regions before the ultrasonic welding process begins. This preliminary protective action prevents the harmful effect of particle generation at the source, blocking the path by which particles would otherwise enter the electrode assembly during welding
2Reliability
If welding process is performed to integrate overlapped uncoated regions, then electrical resistance is reduced, but particles are generated at contacting surfaces
Solution Approach 1:
The insulating member serves as a mediator that enables the welding process to occur without direct metal-to-metal contact between the horn and electrode. This intermediary approach maintains the beneficial electrical connection while eliminating the harmful particle generation mechanism
Solution Approach 2:
The harmful function of particle generation is extracted and separated from the useful welding function by introducing the insulating member. The welding process continues to integrate the uncoated regions and reduce resistance, but the particle generation pathway is removed from the system
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 solution effectively reduces the occurrence of short circuits and enhances the safety and manufacturing efficiency of rechargeable battery electrode assemblies by preventing foreign particles from entering the assembly during the welding process.
Implementation Method 1
An ultrasonic welding process may be used to integrate the overlapped uncoated regions, but vibration occurs and particles may be generated at contacting surfaces between a horn and a substrate during the ultrasonic welding process
Data Source
AI summary
An electrode assembly includes: a first electrode including a first electrode coated region and a first electrode uncoated region at one side of the first electrode coated region; a separator overlapping the first electrode; a second electrode including a second electrode coated region and a second electrode uncoated region at one side of the second electrode coated region; and a foreign particle preventing member on at least one of the first electrode uncoated region and the second electrode uncoated region. The second electrode coated region overlaps the first electrode coated region with the separator therebetween, and the foreign particle preventing member is repeatedly wound about an axis together with the first electrode, the separator, and the second electrode.