Rolling Press Degassing for Fine Gas Removal in Pouch Cells
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Solution Overview
Problem
Existing methods fail to completely remove even a fine gas generated and trapped between a negative electrode, a positive electrode, and a separator of the electrode assembly, and the fine gas trapped between the negative electrode, the positive electrode, and the separator may cause lithium precipitation in the subsequent secondary activation process, which has a negative impact on the performance and lifespan of the secondary battery.
Innovation Solution
A secondary battery degassing apparatus that includes a first and second rolling press with pressing rollers configured to press the secondary battery, pressing the fine gas trapped between the electrodes and separator outward to reduce lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a degas hole is formed in the pouch and suction is applied in a vacuum chamber, then gas can be removed from the battery cell, but fine gas trapped between the negative electrode, positive electrode, and separator cannot be completely removed
Solution Approach 1:
The patent replaces the vacuum suction method with a mechanical pressing method. A pressing member is inserted into the pouch case and applies direct mechanical pressure to the electrode assembly, forcing trapped gas outward through the pouch structure. This mechanical substitution enables complete gas removal including fine gas between electrodes and separator, preventing lithium precipitation that vacuum suction could not eliminate.
Solution Approach 2:
The pressing member acts as an intermediary tool that transmits force from the external pressing mechanism to the electrode assembly inside the pouch. This intermediary enables indirect access to the trapped gas by applying pressure through the pouch case structure, allowing gas to be pushed outward without directly opening or damaging the sealed pouch.
2Reliability
If the pouch case is sealed by thermal fusion, then the battery cell is sealed, but trapped gas cannot escape during activation process
Solution Approach 1:
The patent performs preliminary gas removal by inserting the pressing member and applying pressure before the pouch case is thermally fused and sealed. By removing gas in advance through mechanical pressing, the subsequent sealing process traps minimal gas, preventing pressure buildup and lithium precipitation during later activation processes.
Solution Approach 2:
The patent extracts trapped gas from the electrode assembly by applying external pressure that forces gas outward through the pouch structure. This extraction occurs before sealing, removing the harmful gas substance that would otherwise remain trapped and cause problems during battery activation.
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 apparatus effectively removes the fine gas trapped between the electrodes and separator, improving the performance and lifespan of the secondary battery by minimizing lithium precipitation.
Implementation Method 1
a first rolling press including a plurality of first pressing rollers spaced apart at a predetermined interval; a second rolling press which is disposed to face the first rolling press, the second rolling press including a plurality of second pressing rollers spaced apart at a predetermined interval
Data Source
AI summary
A secondary battery degassing includes a first rolling press on which a plurality of first pressing rollers are mounted at a predetermined interval; a second rolling press which is disposed to face the first rolling press and on which a plurality of second pressing rollers are mounted at a predetermined interval; a first driving device configured to allow a distance between the first rolling press and the second rolling press to vary; and a second driving device driven to allow the first pressing roller and the second pressing roller to rotate. The first pressing roller and the second pressing roller is in rolling contact with the secondary battery disposed between the first rolling press and the second rolling press to press the secondary battery.