Lithium Battery Cell Degassing via Electrolyte Vaporization
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Solution Overview
Problem
Conventional lithium battery cell degassing methods result in incomplete bubble removal and electrolyte solution loss, increasing production costs and time due to the difficulty in handling gel electrolyte solutions.
Innovation Solution
A degassing method involving a sealed bag with a degassing tube, where negative pressure is applied to vaporize electrolyte solution, separating remnant gas and mixing it with vaporized solution to form a mixed gas, which is then extracted and liquefied, allowing for complete bubble removal without electrolyte loss, by using a pressure chamber and controlled gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vacuum degassing is used to remove bubbles from activated lithium battery cells, then bubble removal is attempted, but the gel electrolyte solution is difficult to flow and bubbles cannot be completely removed while much time is spent
Solution Approach 1:
The patent changes the physical state of the electrolyte solution from liquid to vapor by heating it to a temperature above its boiling point (e.g., 100°C or higher). This phase change allows the electrolyte to flow more easily as vapor, enabling complete bubble removal through the degassing tube without the time-consuming process of moving gel electrolyte under vacuum.
Solution Approach 2:
The patent utilizes the phase transition of the electrolyte solution from liquid to vapor through heating. The vaporized electrolyte rises through the degassing tube and condenses back to liquid form, carrying bubbles with it. This phase transition mechanism efficiently removes bubbles without requiring prolonged vacuum application to move gel electrolyte.
2Reliability
If conventional vacuum degassing is used to extract bubbles, then gas is removed, but electrolyte solution is extracted together with the gas and loss of electrolyte solution is unavoidable
Solution Approach 1:
The patent uses phase transition to separate electrolyte loss from bubble removal. The electrolyte vaporizes, carries bubbles through the degassing tube, then condenses back to liquid form inside the tube. The condensed liquid electrolyte flows back into the battery cell through the same degassing tube, while bubbles are vented externally. This eliminates electrolyte loss that occurs in conventional vacuum degassing where electrolyte is extracted with the gas.
Solution Approach 2:
The degassing tube serves as an intermediary channel that facilitates the separation of electrolyte and bubbles. It allows electrolyte vapor to pass through during heating, enables bubble escape, and provides a pathway for condensed electrolyte to return to the cell. This intermediary structure prevents electrolyte loss by keeping the electrolyte circulation path separate from the bubble venting path.
3Quantity of substance
If more electrolyte solution is filled during assembly to compensate for degassing loss, then electrolyte loss is compensated, but production costs are increased
Solution Approach 1:
By using phase transition (vaporization and condensation), the patent enables electrolyte to be recovered and returned to the battery cell during the degassing process itself. This eliminates the need to overfill the cell during assembly to compensate for subsequent electrolyte loss, thereby reducing material waste and lowering production costs.
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 method enables efficient and complete bubble removal from lithium battery cells, reducing production time and costs while maintaining electrolyte solution integrity, thereby enhancing battery performance and reducing manufacturing time.
Implementation Method 1
providing a negative pressure on an external surface of the sealed bag to inflate the sealed bag and thereby decompress the sealed bag to vaporize a part of the electrolyte solution
Implementation Method 2
extracting the mixed gas via the degassing tube, therefore the vaporized electrolyte is pressurized to be liquefied in the degassing tube
Data Source
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AI summary
A degassing method for a lithium battery cell includes the following steps: providing a lithium battery cell (100) including a sealed bag (110), a degassing tube (120) is arranged on the sealed bag (110) and an end of the degassing tube (120) is communicated with a space in the sealed bag (110), the sealed bag (110) is filled with electrolyte solution (130) and a remnant gas (131) is contained therein; providing a negative pressure on an external surface of the sealed bag (110) to inflate the sealed bag (110) and therefore decompress the sealed bag (110) to vaporize a part of the electrolyte solution (130), and the remnant gas (131) is separated from the liquid electrolyte solution (130) and mixed with the vaporized electrolyte solution (130) to form a mixed gas (132); extracting the mixed gas (132) via the degassing tube (120), therefore the vaporized electrolyte (130) is pressurized to be liquefied in the degassing tube (120), and the remnant gas (131) is discharged through the degassing tube (120).