Aircraft Battery Mitigation System for Thermal Runaway

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Solution Overview

Problem

Commercial aircraft face inefficiencies due to the use of bleed air for subsystems, which reduces engine efficiency and adds weight, and lithium-ion batteries are prone to thermal runaway, posing risks during operating cycles.

Innovation Solution

The implementation of a rechargeable lithium cobalt oxide battery system with dielectric separators made of fiber composite for thermal barriers, a chassis with flow channels for condensate management, a battery monitoring unit, a metal enclosure with a vent valve for pressure equalization, and a ventilation conduit to mitigate thermal runaway and failure consequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If lithium-ion batteries are used to provide backup electrical power, then weight is reduced and energy density is increased, but thermal runaway risk increases

Engineering Contradiction:
Improvebattery weightVSAvoidthermal runaway risk
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The battery pack is divided into multiple cell groups, with each group separated by thermal barrier elements. This segmentation prevents thermal runaway from propagating across the entire battery pack, isolating failures to specific segments while maintaining the overall battery system's operational reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Thermal barrier elements are introduced as intermediary components between battery cells. These barriers act as mediators that block heat transfer and prevent thermal runaway propagation, allowing the battery system to maintain high energy density while incorporating safety mechanisms against thermal runaway risks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If thermal barrier elements are added to prevent thermal runaway, then safety is improved, but device complexity increases

Engineering Contradiction:
Improvethermal runaway preventionVSAvoidbattery pack structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thermal barrier elements serve multiple functions simultaneously: they provide thermal isolation to prevent runaway propagation, act as structural support within the battery pack, and facilitate modular assembly. This multi-functionality reduces the need for additional separate safety components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If bleed air is used to power subsystems, then subsystem operation is ensured, but engine efficiency decreases and aircraft weight increases

Engineering Contradiction:
Improvesubsystem power availabilityVSAvoidengine efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical bleed air system with an electrical power system using lithium-ion batteries. This substitution eliminates the need for ducts, valves, and controls associated with bleed air, reducing aircraft weight and improving engine efficiency while maintaining reliable power availability for subsystems through the battery-based electrical system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration reduces the risk of thermal runaway, manages condensate effectively, and ensures safe power delivery while preventing overcharging and pressure buildup, enhancing the reliability and safety of the battery system during aircraft operations.

Implementation Method 1

a plurality of dielectric separators between the battery cells for creating thermal barriers between opposing surfaces of the battery cells

Methodology Applied
Scientific EffectThermal barrier: Thermal Insulation

Implementation Method 2

the lower fixation plate including a plurality of flow channels positioned to collect condensate from the battery cells and move the collected condensate away from the battery cells

Methodology Applied
Scientific EffectCondensate collection: Condensation

Implementation Method 3

the enclosure having ductile containment walls, a normally closed vent configured to open when pressure inside the enclosure corresponds to a battery failure event, and at least one pressure equalization orifice

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP2959521B1Aircraft including mitigation system for rechargeable batteries
Publication Date: 2019.04.10 THE BOEING CO
  • EP2959521B1 patent drawingFigure 1
  • EP2959521B1 patent drawingFigure 2
  • EP2959521B1 patent drawingFigure 3

AI summary

An aircraft comprises a rechargeable battery including an array of battery cells, and means for mitigating consequences of failure of the rechargeable battery due to aircraft operating cycle.