Segmented Membrane Degassing Unit for Low-Pressure Battery Venting
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Solution Overview
Problem
Existing degassing units for electronics cases, particularly battery cases, have high opening pressures due to material limitations, making them non-reclosable and inefficient for rapid pressure relief, which is critical for preventing case bursting in high-voltage storage devices.
Innovation Solution
A degassing unit with a segmented membrane and support ribs that allows for a low opening pressure of up to 50 mbar, enabling rapid gas release while maintaining a sealed state, utilizing a single impermeable membrane with segmentation lines and convex shape for enhanced sealing and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional PTFE membrane is used for degassing, then the membrane can maintain sealing properties, but the opening pressure is high (150-300 mbar) and the membrane cannot be reclosed after bursting
Solution Approach 1:
The membrane is divided into multiple segments (at least two) that are connected at the rim but can move independently. The segmentation lines create gaps between segments under pressure, allowing the membrane to open at low pressure (≤50 mbar) while maintaining sealing when closed. This resolves the contradiction by enabling both low opening pressure and reliable sealing through the segmented structure.
Solution Approach 2:
The membrane transitions from a static, fixed structure to a dynamic one where segments can move relative to each other. Under normal conditions, segments remain closed together providing sealing. When pressure differential exceeds the elastic restoring force, segments separate to allow gas passage, and can return to closed position when pressure equalizes, enabling reclosability.
2Productivity
If the total open area of the degassing opening is increased to at least 200 mm2 for rapid pressure relief, then emergency venting efficiency improves, but the membrane becomes more difficult to close again after opening
Solution Approach 1:
The membrane is divided into multiple segments that can separate to create a large total open area (≥200 mm2) for rapid pressure relief. Each segment acts independently and can return to its closed position through elastic restoration, enabling the large opening area to be achieved without sacrificing reclosability.
Solution Approach 2:
The membrane material properties are selected to provide appropriate elastic restoring force that can close segments after they have separated. The elasticity parameter is optimized so that segments can withstand the forces during rapid opening while still returning to closed position, enabling both high productivity during emergency venting and ease of reclosure.
3Stress or pressure
If segmentation lines penetrate through the membrane to create gaps for low-pressure opening, then opening pressure decreases to ≤50 mbar, but the membrane structure becomes more complex
Solution Approach 1:
The membrane is segmented by penetration lines that create controlled gaps. These segmentation lines are simple linear features that divide the membrane into segments, achieving low opening pressure (≤50 mbar) through the gaps while adding minimal structural complexity compared to a fully integrated membrane design.
Solution Approach 2:
The segmented membrane maintains its flexibility and thin-film characteristics despite the segmentation lines. The segments remain connected at the rim and can move elastically, preserving the membrane's simple, flexible nature while enabling low-pressure opening through the segmentation gaps.
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 solution achieves rapid and efficient pressure relief with a low opening pressure, ensuring the case remains sealed during normal conditions and prevents external contamination, while being cost-effective and easy to manufacture.
Implementation Method 1
If the internal pressure of the case exceeds the external pressure, the segments of the membrane move away from each other. Thus, the degassing unit opens. Gas from inside the case may escape to the environment.
Implementation Method 2
In an unloaded state of the degassing membrane, i.e. if an outside pressure of the case equals its internal pressure, the segments of the membrane contact each other along the segmentation line, i.e. the segmentation line has vanishing width. Thereby, the degassing unit is closed.
Data Source
AI summary
A degassing unit for an electronics case includes a base body attachable to the electronics case and configured to seal against a perimeter of an aperture in the electronics case, the base body including a degassing opening, a membrane covering the degassing opening of the base body and including at least one segmentation line penetrating through the membrane, and at least one support rib abutting adjacent segments of the membrane along the at least one segmentation line. Each of the membrane and the at least one support rib has a convex shape facing away from the base body.