Open-Pored Pressure Equalization Filter for Battery Housings

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Solution Overview

Problem

Current pressure compensation devices in large-format battery systems face issues with mechanical damage, oil contamination, and particulate contamination due to their susceptibility to pressure fluctuations and environmental factors, leading to reduced service life and increased risk of explosion or corrosion.

Innovation Solution

A pressure compensation device utilizing an open-pored element with an average pore diameter of 2 to 100 μm, designed to be lipophobic and hydrophobic, which provides improved filter functionality, reduced susceptibility to oil contamination, and enhanced mechanical robustness, ensuring effective gas exchange and protection against mechanical damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a hermetically sealed housing is used, then protection against moisture and dust is improved, but pressure fluctuations cause overpressures or underpressures that negatively influence cell service life

Engineering Contradiction:
Improvemoisture and dust penetrationVSAvoidcell service life
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies a porous membrane material that allows pressure equalization between the housing interior and exterior while blocking moisture and dust. The porous structure enables gas permeability for pressure compensation while the pore size is sufficient to filter harmful particles and liquid droplets, thus resolving the contradiction between hermetic sealing and pressure equalization.

Inventive Principle:
Principle #31Porous materials

2Reliability

If the dead volume is filled with solid or liquid substances, then pressure compensation is improved, but the weight of the battery system significantly increases

Engineering Contradiction:
Improvepressure compensationVSAvoidbattery system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The porous membrane passively compensates for pressure differences by allowing air to pass through when pressure differences occur, eliminating the need for heavy solid or liquid filling materials. This provides pressure compensation functionality while maintaining lightweight battery system design.

Inventive Principle:
Principle #31Porous materials

3Object-affected harmful factors

If microporous membranes with pore diameter under 1 μm are used, then moisture blocking is improved, but oil contamination and particulate deposition significantly reduce service life

Engineering Contradiction:
Improvemoisture blockingVSAvoidservice life
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent specifies a porous membrane with pore diameter of 1 μm to 100 μm, which is larger than conventional microporous membranes. This larger pore size prevents oil and particulate matter from blocking the pores through capillary effects, while still providing sufficient moisture blocking capability, thus significantly extending service life.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent changes the critical parameter of pore diameter from under 1 μm to 1 μm - 100 μm. This parameter change fundamentally alters the interaction with contaminants: larger pores prevent oil and particle accumulation while maintaining moisture blocking function, thereby resolving the service life issue.

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If breathable water block elements are used, then moisture penetration is prevented, but water vapor condensation accumulates in the housing interior

Engineering Contradiction:
Improvemoisture penetrationVSAvoidcondensate accumulation
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The porous membrane with 1 μm to 100 μm pore diameter allows water vapor to pass through while blocking liquid water through surface tension effects. This prevents condensate accumulation in the housing interior while still providing effective moisture blocking, resolving the contradiction between moisture protection and vapor permeability.

Inventive Principle:
Principle #31Porous materials

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 open-pored element effectively compensates for pressure differences, reduces contamination risks, and extends the service life of the device by preventing oil and particulate penetration, while maintaining high breathability and mechanical strength, thus enhancing the safety and reliability of battery systems.

Implementation Method 1

The present invention relates to a pressure compensation device for a housing having a dead volume, in particular an electrochemical power source, with at least one open-pored element

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

an open-pored element with an average pore diameter of 2 to 100 μm, designed to be lipophobic and hydrophobic

Methodology Applied
Scientific EffectLipophobic effect: Hydrophobe

Implementation Method 3

designed to be lipophobic and hydrophobic, which provides improved filter functionality

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentEP2503199B1Pressure equalisation device with filter function for housing with a dead volume
Publication Date: 2016.09.28 CARL FREUDENBERG KG
  • EP2503199B1 patent drawingFigure 1~2F
  • EP2503199B1 patent drawingFigure 3A~3H
  • EP2503199B1 patent drawingFigure 4A~5D

AI summary

A pressure equalization device (7) for a housing (1) having a dead volume, in particular an electrochemical power source, with at least one open-pore element (9) having a mean pore diameter of 2 to 100 µm, preferably of 5 to 50 µm, solves the problem of providing an improved or at least an alternative embodiment for a pressure equalization device, which is characterized in particular by an improved filter function and a lower susceptibility to oil contamination and mechanical damage.The present invention also relates to the use of at least one open-pore element (9) in electrochemical power sources, such as double-layer capacitors, batteries, or fuel cells, in housings (1) thereof, in transport containers for electrochemical power sources, in housings (1) for electrical components, such as converters or rectifiers, in control cabinets, in chemical, biochemical, or biological reactors, or in electric motors as a pressure equalization element. This allows the aforementioned components to be designed with adequate ventilation and protected against the potential ingress of liquids and dirt particles into the interior of the housing.