Pouch Cell Degassing During Formation Charging
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Solution Overview
Problem
The conventional lithium ion secondary battery cell formation process is inefficient due to the backflow of degassed gas into the electrode assembly, leading to prolonged process times, increased labor, and reduced productivity, as well as capacity reduction and safety concerns.
Innovation Solution
A lithium ion secondary battery manufacturing system that includes a chamber with a pressure plate and a pointed portion to remove gas generated during charging by boring a hole in the pouch of the battery, allowing real-time discharge of gases and utilizing a temperature control device to optimize charging conditions, along with a controller to manage the operation of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional formation process is used to charge the lithium ion secondary battery, then the battery cell is formed with a passivation film, but gas generated during charging flows back into the electrode assembly causing capacity reduction and requiring prolonged process time
Solution Approach 1:
The patent extracts the harmful gas from the charging system by introducing a dedicated gas discharge path through the pressure plate. The pressure plate includes a discharge path that allows gas to be removed from the battery cell during charging, preventing gas backflow into the electrode assembly while maintaining the formation process functionality.
Solution Approach 2:
The pressure plate serves as an intermediary component between the charging system and the battery cell. It provides both pressing force for cell formation and a controlled gas discharge path, mediating between the need to maintain cell structure and the need to remove harmful gas during charging.
2Productivity
If gas is allowed to accumulate during battery formation charging, then the charging process can be completed, but the gas flows back into the electrode assembly deteriorating cell performance
Solution Approach 1:
The harmful gas is extracted from the battery cell through the discharge path in the pressure plate. This allows continuous charging without gas accumulation, improving productivity while eliminating the harmful backflow effect that would otherwise require additional degassing steps.
Solution Approach 2:
The gas that would normally be harmful is now channeled through a controlled discharge path. The pressure plate converts the potentially harmful gas accumulation into a controlled discharge process, where gas is removed through designated paths without contaminating the electrode assembly, thus improving both productivity and cell performance.
3Stability of the object's composition
If the battery is pressed during charging to prevent expansion, then cell structure is maintained, but gas cannot be discharged without creating additional complexity
Solution Approach 1:
The pressure plate performs multiple functions simultaneously: it applies pressing force to maintain cell structure during charging and provides a gas discharge path to remove generated gas. This multi-functionality eliminates the need for separate gas removal mechanisms, reducing device complexity while maintaining structural stability.
Solution Approach 2:
The patent merges the structural support function and gas discharge function into a single integrated pressure plate component. The discharge path is incorporated directly into the pressure plate structure, combining what would otherwise be separate systems into one unified component, thereby simplifying the overall device.
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 reduces the initial charging time and overall production time for lithium ion secondary batteries, enhances productivity, prevents gas backflow, and extends the practical service life by ensuring efficient gas removal and controlled temperature conditions.
Implementation Method 1
a pointed portion provided in the chamber and configured to bore a hole in a pouch of the lithium ion secondary battery to enable gas generated during the electrical charging to be removed from the pouch
Implementation Method 2
a pressure plate provided in the chamber and configured to press the lithium ion secondary battery when the lithium ion secondary battery is electrically charged
Implementation Method 3
a temperature control device provided in the chamber and configured to adjust an internal temperature of the chamber
Implementation Method 4
a pump configured to create a vacuum pressure in the chamber
Data Source
AI summary
A lithium ion secondary battery system includes a chamber to accommodate a lithium ion secondary battery, a charging/discharging device for electrically charging and discharging the lithium ion secondary battery, a pressure plate disposed in the chamber and configured to press the lithium ion secondary battery when the lithium ion secondary battery is electrically charged, a pointed portion disposed in the chamber and configured to bore a hole in a pouch of the lithium ion secondary battery to enable gas generated during the electrical charging of the lithium ion secondary battery to be removed from the pouch, and a sealer configured to seal the pouch after the gas is removed.