Aircraft Battery Pack Barriers for Thermal Runaway Containment

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Solution Overview

Problem

Aircraft battery packs face the risk of thermal runaway propagation, which can lead to catastrophic failure due to undetectable defects or manufacturing variability, posing severe consequences in aerospace applications where weight and power density are critical considerations.

Innovation Solution

Incorporating a battery pack design with cylindrical cells surrounded by anti-propagation barriers that include gaps between the barrier walls and cell walls, optimized in size and configuration to contain debris and reduce failure propagation, combined with flow control devices and sensing circuitry to manage thermal events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick barrier walls are used to prevent thermal runaway propagation, then safety is improved, but weight and power density deteriorate

Engineering Contradiction:
ImprovesafetyVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs thin barrier walls (thin films) instead of thick protective structures. The barrier walls are designed to be sufficiently thin to maintain low weight while still providing effective containment of thermal runaway events. This is achieved through careful optimization of barrier thickness to provide adequate protection without excessive mass penalty.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent optimizes the thickness parameter of the barrier walls to achieve the right balance between safety and weight. By adjusting this critical parameter, the design achieves adequate thermal runaway containment while minimizing the weight penalty associated with protective structures.

Inventive Principle:
Principle #35Parameter changes

2Power

If barrier walls are placed close to battery cells to maximize power density, then power density is improved, but thermal runaway containment capability deteriorates

Engineering Contradiction:
Improvepower densityVSAvoidthermal runaway containment
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent optimizes the gap distance parameter between barrier walls and battery cells to achieve the optimal balance between power density and thermal runaway containment. This parameter optimization allows the system to maintain high cell packing density while ensuring adequate containment capability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If gaps are added between barrier walls and cells to reduce failure propagation, then thermal runaway containment is improved, but device complexity increases

Engineering Contradiction:
Improvethermal runaway containmentVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces gaps that segment the space between barrier walls and battery cells. This segmentation creates distinct containment zones that improve thermal runaway containment while the gaps themselves are simple geometric features that do not significantly increase manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4418409A1Battery pack suitable for aircraft preventing propagation of cell failures
Publication Date: 2024.08.21 ROLLS ROYCE PLC
  • EP4418409A1 patent drawingFigure 1A~1B
  • EP4418409A1 patent drawingFigure 2A~2B
  • EP4418409A1 patent drawingFigure 3A~3C

AI summary

Battery packs 100, which may be used in vehicles including aircraft 10, 20, are disclosed. One such battery pack 100 comprises: a plurality of cylindrical battery cells 101, each one of the plurality of cells 101 having a cylindrical outer cell wall 1010 that extends in a z-direction between opposed first and second ends of the cell 1011, 1012; a carrier structure 112 that locates the battery cells 101 relative to one another and arranges them in an array 1000 in an x-y plane perpendicular to the z-direction; and a plurality of barriers 102 for preventing propagation of thermal runaway between cells 101 of the array 1000, each one of the plurality of barriers 102 forming a barrier wall 1020 that surrounds a group of one or more of the cells 101. A gap is defined between the barrier wall 1020 of each respective barrier 102 and the outer cell wall 1010 of each of the respective one or more cells 101 enclosed by the respective barrier. The gap 103 may be sized to reduce a likelihood of a cell failure propagating to other cells 101 of the array 1000.