Folded Membrane Carrier for Battery Case Cold Venting

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Solution Overview

Problem

Conventional venting units for battery cases are inadequate for releasing moderate gas pressures during cold venting events due to limited membrane area, and adapting emergency degassing units for cold venting risks dust or water ingress.

Innovation Solution

A venting unit with a membrane assembly comprising carrier segments and film hinges, allowing the membrane to be folded to increase the gas exchange area, while maintaining a sealed barrier against dust and water, using polytetrafluoroethylene or polyethylene terephthalate membrane segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the membrane area is increased to release moderate gas pressure during cold venting, then the gas exchange capacity is improved, but the installation space requirement increases

Engineering Contradiction:

Improvegas exchange capacityVSAvoidinstallation space

Core Design Contradiction:

Quantity of substanceVSArea of stationary object

Solution Approach 1:

The membrane is folded along film hinges to transform from a flat two-dimensional configuration to a three-dimensional folded structure. This dimensional transformation allows the membrane area to exceed the vent opening area while fitting within the same installation space, resolving the contradiction between gas exchange capacity and space requirement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The folded membrane structure is nested within the housing part, with the membrane carrier folded along film hinges to create a compact configuration. The membrane assembly is embedded in the housing part, allowing the expanded membrane area to be contained within the original space envelope.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Quantity of substance

If emergency degassing units are adapted for cold venting, then the gas release capability is improved, but the risk of dust or water ingress increases

Engineering Contradiction:

Improvegas release capabilityVSAvoiddust or water ingress risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A flexible membrane made of hydrophobic material (polytetrafluoroethylene or polyethylene terephthalate) is used to cover the vent opening. The membrane remains intact during cold venting, allowing gas passage while blocking dust and water. The membrane is folded along film hinges to increase surface area while maintaining the protective barrier function.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The membrane material is selected to be porous or permeable to gas molecules while maintaining a continuous barrier against larger particles like dust and water droplets. The membrane segments are fixed to the carrier around the flow windows, creating a selective barrier that allows gas exchange while preventing harmful factor ingress.

Inventive Principle:

Principle #31Porous materials

3Quantity of substance

If spring-loaded valves are adapted for cold venting, then the pressure relief function is improved, but the risk of unintentional opening in rough operating conditions increases

Engineering Contradiction:

Improvepressure relief functionVSAvoidunintentional opening risk

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Instead of a spring-loaded valve mechanism, a flexible membrane is used that responds passively to pressure differential. The membrane allows gas passage when internal pressure exceeds external pressure by flexing through the flow windows, while the hydrophobic material and membrane integrity prevent opening under rough operating conditions like gravel road vibration or pot-hole impacts.

Inventive Principle:

Principle #30Flexible shells and thin films

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 design enables efficient release of high venting volumes with minimal aperture size, preventing dust and water ingress, and maintaining the battery case's integrity during cold venting events.

Implementation Method 1

The membrane assembly allows gas to exit or enter through the vent opening, while blocking water and dust

Methodology Applied

Scientific EffectHydrophobic barrier: Hydrophobe

Implementation Method 2

The membrane segments are designed to stay intact during such a cold venting incident. Thus, the case remains sealed against the environment with respect to dust or water

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 3

By folding the membrane carrier at the film hinges between its carrier segments, the membrane is erected in the direction perpendicular to the diameter or width of the vent opening. This allows increasing the total area available for gas exchange

Methodology Applied

Scientific EffectFolding: Folding

Data Source

PatentUS20260081302A1Folded membrane carrier for battery case venting

Publication Date: 2026.03.19 MANN HUMMEL GMBH

AI summary

A venting unit for a battery case, the venting unit comprising a housing part delimiting a vent opening, and a membrane assembly spanning across the vent opening and comprising a membrane carrier comprising carrier segments and flow windows respectively disposed through the carrier segments, and membrane segments respectively covering the flow windows. Each adjacent pair of the carrier segments is folded against one another along a film hinge disposed therebetween.