Pouch Cell Degassing Channel With Pressure-Activated Closing Element

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Solution Overview

Problem

Lithium-ion pouch cells in vehicle batteries face issues with uncontrolled gas release due to decomposition reactions, leading to potential damage or destruction from increased internal pressure, which reduces energy density and requires additional safety measures.

Innovation Solution

Integration of a degassing channel with a closing element that automatically opens when excess pressure occurs, allowing controlled and directed gas release, preventing uncontrolled bursting and protecting neighboring cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pouch cell is used without a degassing channel, then the structure remains simple and energy density is maintained, but uncontrolled gas accumulation causes increased internal pressure leading to pouch bursting or damage

Engineering Contradiction:

ImprovesafetyVSAvoidstructure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pouch cell structure is segmented by introducing a dedicated degassing channel that separates the gas venting function from the sealed pouch structure. This allows the pouch to maintain its integrity while providing a controlled pathway for gas release, resolving the contradiction between safety and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A degassing channel acts as an intermediary element between the pouch interior and exterior, providing a controlled interface for gas release. This intermediary structure enables safe gas venting without compromising the overall pouch integrity or requiring complex additional safety systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If additional safety measures are added to protect against uncontrolled degassing, then safety is improved, but energy density is reduced due to additional space requirements

Engineering Contradiction:

ImprovesafetyVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The harmful function of uncontrolled gas accumulation is extracted from the pouch cell system by introducing a dedicated degassing channel. This separates the gas venting function from the energy-storing function, allowing safety measures that minimize impact on energy density.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The degassing channel utilizes the flexible pouch film structure to create an integrated safety feature that requires minimal additional space. The channel is formed within or as part of the existing pouch structure, avoiding significant volume consumption and preserving energy density.

Inventive Principle:

Principle #30Flexible shells and thin films

3Quantity of substance

If the pouch cell is designed with high energy density, then space utilization is optimized, but the pouch becomes more susceptible to damage from internal pressure increase

Engineering Contradiction:

Improveenergy densityVSAvoidresistance to pressure

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The harmful effect of gas generation during battery operation is converted into a beneficial controlled venting process through the degassing channel. The channel transforms the potential damage-causing pressure buildup into a controlled gas release mechanism, allowing high energy density design without compromising pressure resistance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of operation

If a degassing channel is integrated into the pouch bag, then controlled gas release is enabled, but the fluid-tight sealing is compromised

Engineering Contradiction:

Improvecontrolled degassingVSAvoidfluid-tight sealing

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The pouch structure exhibits local quality differentiation: the majority of the pouch maintains fluid-tight sealing properties, while the specific region of the degassing channel provides controlled gas permeability. This localized functional differentiation enables both sealed operation and controlled degassing.

Inventive Principle:

Principle #3Local quality

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 ensures safe and controlled degassing, preventing damage to the pouch cell and surrounding components, maintaining energy density and reducing the need for additional safety measures.

Implementation Method 1

when excess pressure occurs in the interior of the bag, the closing element is pressed out of the degassing channel by the excess pressure

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4020675A1Pouch cell

Publication Date: 2022.06.29 POWERCO SE

Figure 1~2
Figure 3

AI summary

The invention relates to a pouch cell (2) comprising a pouch bag (4), wherein a degassing channel (10) penetrating the pouch bag (4) is provided, which connects a pouch interior with an environment, wherein a closing element (12) is seated in the degassing channel (10), and wherein the closing element (12) is designed such that when an overpressure occurs in the pouch interior, the closing element (12) is forced out of the degassing channel (10) by the overpressure, thereby releasing the degassing channel (10).