Battery Electrolyte Filling With Air-Permeable Port Sealing
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Solution Overview
Problem
The existing methods for manufacturing secondary batteries, such as lithium ion batteries, face inefficiencies in impregnating nonaqueous electrolytes into the electrode body, leading to prolonged manufacturing times and potential electrolyte volatilization.
Innovation Solution
A manufacturing method involving the use of a first sealing member with an air-permeable film to create negative pressure within the battery case, allowing efficient impregnation of the electrolyte while minimizing volatilization, by temporarily sealing the solution introduction port with an air-permeable film that allows air permeation but restricts vapor permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solution introduction port is kept open during impregnation, then the impregnation efficiency is improved, but the electrolyte volatilizes to the outside
Solution Approach 1:
The patent employs a flexible sealing bag that can be temporarily attached to the solution introduction port. This thin film structure allows controlled sealing - the bag can be inflated to seal the port during impregnation to prevent volatilization, then deflated and removed to allow efficient electrolyte introduction. The flexible nature of the bag enables it to adapt to the port opening while providing effective sealing when needed.
Solution Approach 2:
The sealing bag transitions between different states - uninflated/open for efficient electrolyte introduction, and inflated/sealed for preventing volatilization during impregnation. This dynamic state change allows the system to optimize for different operational requirements at different times, resolving the contradiction between impregnation efficiency and volatilization prevention.
2Loss of substance
If the solution introduction port is sealed during impregnation, then the electrolyte volatilization is prevented, but the impregnation efficiency decreases
Solution Approach 1:
The sealing bag provides dynamic sealing capability - it can be inflated to create a seal when volatilization prevention is needed, and deflated when efficient electrolyte introduction is required. This temporal separation of sealing and open states allows the system to achieve both volatilization prevention and impregnation efficiency at different stages of the process.
Solution Approach 2:
The sealing bag is prepared in advance and can be quickly deployed to seal the solution introduction port before impregnation begins. This preliminary preparation ensures that when sealing is needed, it can be implemented immediately without compromising the impregnation process that follows.
3Loss of substance
If a non-air-permeable sealing member is used, then the electrolyte volatilization is prevented, but air permeation is blocked affecting impregnation
Solution Approach 1:
The sealing bag's permeability characteristics are dynamically controlled through inflation and deflation. When inflated, it provides effective sealing against volatilization. When deflated, it allows air permeation necessary for efficient impregnation. This dynamic control resolves the contradiction between maintaining volatility prevention and allowing necessary air exchange.
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 enhances the impregnation efficiency of the nonaqueous electrolyte into the electrode body, reducing manufacturing time and minimizing electrolyte loss, thereby improving the overall production process.
Implementation Method 1
the first sealing member includes an air permeable film having air permeability. Air permeation is enabled between the inside of the battery case after the temporary sealing and external atmosphere via the air permeable film. The permeability of a vapor derived from the nonaqueous electrolyte with respect to the air permeable film is smaller than the permeability of water vapor with respect to the air permeable film.
Data Source
AI summary
Provided is a technique capable of improving impregnation efficiency of a nonaqueous electrolyte into an electrode body. A manufacturing method herein disclosed includes producing a negative pressure in an inside of a battery case; introducing a nonaqueous electrolyte into the inside of the battery case; establishing communication between the inside of the battery case and external atmosphere; temporarily sealing a solution introduction port using a first sealing member, impregnating the electrode body with a nonaqueous electrolyte; opening the solution introduction port; and, sealing the solution introduction port using a second sealing member. Herein, the first sealing member includes an air permeable film. Air permeation is enabled between the inside of the battery case after the temporary sealing and external atmosphere. The permeability of a vapor derived from the nonaqueous electrolyte with respect to the film is smaller than the permeability of water vapor.