Pouch Battery Stepped Sealing for Tab Positioning
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Solution Overview
Problem
The miniaturization of pouch type lithium secondary batteries leads to narrow gaps between electrode tabs, making it difficult to accurately position the tabs during the sealing process, resulting in electrical shorts and sealing defects.
Innovation Solution
A pouch type lithium secondary battery design that incorporates a stepped part in the sealing portion for electrode tabs, surrounded by an insulating member, which reduces the risk of electrical shorts and improves sealing pressure distribution, using protection tapes to maintain insulation and facilitate proper sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery size is minimized, then the weight and volume are reduced, but the gap between electrode tabs becomes very narrow making positioning difficult
Solution Approach 1:
The sealing portion is divided into a first sealing portion and a second sealing portion at different heights, creating distinct sealing zones. The electrode tabs are positioned in the first sealing portion while the protection tape is sealed in the second sealing portion, separating the positioning function from the sealing function to improve manufacturing precision in miniaturized batteries
Solution Approach 2:
The invention introduces a vertical height dimension to the sealing structure by creating stepped portions at different heights. This multi-level sealing structure allows electrode tabs and protection tapes to be sealed at different vertical positions, providing additional spatial freedom for accurate positioning in narrow gaps
2Length of moving object
If the battery width is reduced, then the overall dimensions are minimized, but it becomes difficult to weld electrode tabs to electrode plates and maintain proper seal
Solution Approach 1:
The sealing process is segmented into two distinct operations: first sealing the electrode tabs in the first sealing portion, then sealing the protection tapes in the second sealing portion. This segmentation allows each sealing operation to be optimized independently, improving welding and sealing workability even in reduced-width batteries
Solution Approach 2:
The electrode tabs are first positioned and sealed in the first sealing portion before the protection tapes are sealed in the second sealing portion. This preliminary action ensures proper positioning and welding of electrode tabs before the final protection tape sealing, maintaining manufacturing ease in miniaturized designs
3Productivity
If electrode tabs are not properly positioned at stepped part, then manufacturing speed is maintained, but electrical short or sealing defects occur
Solution Approach 1:
The stepped sealing structure creates a vertical height difference between the first and second sealing portions. This height dimension provides a built-in positioning guide that ensures electrode tabs are correctly positioned before sealing, maintaining both productivity and reliability without requiring complex positioning mechanisms
Solution Approach 2:
The stepped sealing structure itself serves as a positioning mechanism. The geometry of the first and second sealing portions automatically guides the electrode tabs and protection tapes into correct positions during the sealing process, eliminating the need for external positioning devices and ensuring reliable electrical isolation
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 design stabilizes the sealing quality, enhances manufacturing efficiency by improving workability, and ensures reliable sealing while reducing the risk of electrical shorts and defects.
Implementation Method 1
surrounded by an insulating member, which reduces the risk of electrical shorts and improves sealing pressure distribution
Implementation Method 2
the sealed pouch type bare cell is manufactured by bonding upper and lower pouch films to open peripheral parts by heating
Data Source
AI summary
A pouch type lithium secondary battery includes: an electrode assembly including electrode tabs respectively connected to two electrodes, the two electrodes having different polarities; and a case to house the electrode assembly such that the electrode tabs extend to the outside of the case, wherein one stepped part through which the two electrode tabs simultaneously extend is formed in a sealing portion of the case. In the electrode sealing portion of the pouch type lithium secondary battery having short width, sealing of the case is improved by the one stepped part, thereby improving efficiency of the manufacturing process of the battery.