Battery Vent Assembly Membrane for Electrolyte Shielding
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Solution Overview
Problem
Components in vented cells or batteries, such as flame arresters and pressure valves, are prone to contamination and damage due to electrolyte leakage during service, handling, or transportation, leading to clogging and loss of functionality.
Innovation Solution
A vent assembly incorporating an expanded polytetrafluoroethylene (ePTFE) membrane is used to shield these components from electrolyte contact, supported by an elastomeric seal within a vent body, ensuring tight sealing and protection against contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame arrester or pressure valve is directly exposed in the vent opening, then gas release is enabled, but the component becomes contaminated or damaged by electrolyte leakage during service, handling, or transportation
Solution Approach 1:
An ePTFE membrane is introduced as an intermediary component between the electrolyte and the flame arrester/pressure valve. The membrane allows gas molecules to pass through while blocking electrolyte liquid, thereby protecting the component from contamination while maintaining venting functionality
Solution Approach 2:
A thin ePTFE membrane is used to create a selective barrier that permits gas transmission while preventing electrolyte contact with the component. The membrane's porous structure allows gas molecules to diffuse through while its hydrophobic properties repel the electrolyte liquid
2Reliability
If an ePTFE membrane is added to shield the component, then protection from electrolyte contamination is achieved, but the device complexity increases
Solution Approach 1:
The ePTFE membrane is nested within the existing vent body structure, fitting into the available space without requiring a completely new design. The membrane is positioned between the vent opening and the component, utilizing the existing geometric configuration of the vent assembly
Solution Approach 2:
The thin film nature of the ePTFE membrane allows it to be integrated into the existing vent assembly with minimal additional volume and structural modification, adding protection without significantly increasing device complexity
3Reliability
If a seal is added between the vent body and membrane, then tight sealing is achieved, but the device complexity increases
Solution Approach 1:
The elastomeric seal utilizes its inherent elastic properties to create a tight seal between the vent body and membrane when compressed during assembly. The seal's self-generating sealing force eliminates the need for additional sealing mechanisms or complex fastening systems
Solution Approach 2:
The elastomeric seal's ability to deform and conform to the mating surfaces changes the sealing interface from a rigid to a flexible contact, ensuring tight sealing while accommodating manufacturing tolerances and assembly variations
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 ePTFE membrane effectively prevents electrolyte contamination, maintaining component functionality and compliance with safety standards during transportation and service, while allowing gas release.
Implementation Method 1
an expanded polytetrafluoroethylene (ePTFE) membrane in the vent assembly to protect the flame arrester and/or the pressure valve from being contaminated by the electrolyte
Data Source
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AI summary
A vent assembly for a battery or a electrochemical cell may include a vent body configured to connect to a battery casing or a electrochemical cell body, a flame arrester and/or a pressure valve disposed in the vent body, a membrane disposed in the vent body between a vent opening of the battery or the electrochemical cell and the flame arrester and/or the pressure valve, and that is configured to shield the flame arrester and/or the pressure valve from electrolyte solution of the battery or the electrochemical cell, and a seal disposed between the vent body and the membrane. Also, a battery including a vent assembly.