Battery Cell Housing Cover Flap for Protected Burst Venting

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Solution Overview

Problem

Direct cooling of high-performance battery cells can lead to pressure differentials in the cooling system, causing the burst region of the cell housing to become weakened, potentially resulting in leakage or unintended opening, which compromises the safety and reliability of pressure dissipation.

Innovation Solution

A cell housing design featuring a cover flap that is fastened pressure-tightly over the burst region, absorbing pressure fluctuations and ensuring the burst region is not mechanically stressed, with a gaseous volume maintaining a predefined standard pressure to ensure controlled pressure dissipation, and the cover flap can detach or burst to dissipate pressure safely.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If direct cooling is used to cool battery cells, then cooling efficiency is improved, but pressure differentials cause the burst region to weaken and potentially leak or open unintentionally

Engineering Contradiction:

Improvecooling efficiencyVSAvoidburst region integrity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cell housing is segmented into a pressure-tight envelope portion and a separate burst region portion. The burst region is designed as a distinct structural element that can fail independently without compromising the entire housing integrity, allowing controlled pressure relief while maintaining cooling efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The burst region is pre-designed with specific geometric features and material properties that enable it to burst at a predetermined pressure threshold. This preliminary design ensures that when excessive pressure occurs, the burst region will fail in a controlled manner to relieve pressure before it can damage other components or cause uncontrolled thermal runaway.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the burst region is designed to function at atmospheric pressure, then manufacturing is simplified, but pressure fluctuations in the cooling system cause the burst region to bulge and form cracks

Engineering Contradiction:

Improveburst region designVSAvoidburst region stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The burst region is designed with localized geometric features such as notches, holes, or varying wall thicknesses that create stress concentration points. These local quality modifications enable the burst region to respond predictably to pressure changes by bursting at specific locations while the rest of the housing maintains its structural integrity and atmospheric pressure compatibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The burst region incorporates geometric parameters such as notch radius, hole diameter, or wall thickness variations that are optimized to create controlled stress distribution. By changing these geometric parameters, the burst region can be tuned to withstand normal pressure fluctuations during manufacturing and assembly while still bursting at the desired pressure threshold during operation.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the burst region is exposed to cooling medium pressure, then cooling contact is maximized, but pressure strokes cause the burst region to weaken over time

Engineering Contradiction:

Improvecooling contactVSAvoidburst region strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The burst region is extracted from the pressure-tight envelope portion of the housing and designed as a separate structural element. This extraction allows the burst region to be positioned where it can contact the cooling medium for efficient heat transfer, while its specialized design protects it from the damaging effects of pressure strokes that would otherwise weaken the main housing structure over time.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Enhances operational safety and reliability by preventing mechanical stress on the burst region, ensuring controlled pressure dissipation, and allowing for potential reuse of the cover flap, thus improving the safety and sustainability of battery cell cooling systems.

Implementation Method 1

the cover flap is configured to absorb pressure fluctuations of the cooling medium so that the burst region is not mechanically stressed

Methodology Applied

Scientific EffectPressure fluctuation absorption: Absorption (physical)

Implementation Method 2

the positive pressure in the interior of the cell housing can be dissipated over the burst region as desired

Methodology Applied

Scientific EffectPressure dissipation: Depressurisation

Data Source

PatentUS20240088512A1Cell housing with protection of a burst region

Publication Date: 2024.03.14 DR ING H C F PORSCHE AG

AI summary

A cell housing (10) of a directly cooled battery cell and a battery cell having the cell housing (10) are provided, as well as a vehicle having such a battery cell. The cell housing (10) is configured so that a cooling medium flows directly around it. The cell housing (10) has at least one burst region (11) configured to burst at a defined positive pressure inside the cell housing (10) and to dissipate the positive pressure. Furthermore, the cell housing (10) has a cover flap (12) that is fastened to the cell housing (10) in a pressure-tight manner and extends completely across the burst region (11).