Liquid-Cooled Battery Casing for Thermal Runaway Non-Propagation

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Solution Overview

Problem

Aircraft batteries face challenges in thermal regulation due to the risk of thermal runaway, particularly in high electricity demand scenarios, where existing solutions like metallic heat exchange plates are not suitable and may not meet the stringent requirements for non-propagation of thermal runaway, as mandated by certifications like RTCA DO-311A.

Innovation Solution

A battery thermal protection device with a housing containing a network of channels for thermal regulation liquid, which vaporizes to enhance cooling, and is designed to withstand pressure from potential cell explosions, using additive manufacturing for complex geometry and ensuring sufficient mechanical strength, while minimizing pressure losses and optimizing temperature uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metallic heat exchange plate is used for battery cooling, then thermal regulation capability is improved, but device mass increases significantly

Engineering Contradiction:
Improvethermal regulation capabilityVSAvoiddevice mass
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent uses a liquid cooling system with channels instead of solid metallic plates. The cooling liquid circulates through the channel network to absorb and transport heat, replacing the need for heavy metallic heat exchange plates while maintaining effective thermal regulation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The housing structure incorporates a network of channels that allow cooling liquid to flow through, creating a porous-like thermal management structure. This enables heat dissipation through fluid circulation rather than relying on solid conductive materials, reducing overall device mass.

Inventive Principle:
Principle #31Porous materials

2Strength

If the housing wall thickness is increased to withstand explosion pressure, then mechanical strength is improved, but heat transfer efficiency decreases

Engineering Contradiction:
Improvemechanical strengthVSAvoidheat transfer efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The housing employs different wall thicknesses in different locations: thicker walls in areas requiring explosion containment and thinner walls where heat transfer is prioritized. This localized variation optimizes both mechanical strength and thermal efficiency without compromising either function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The housing combines materials with different properties to simultaneously achieve high mechanical strength for explosion resistance and good thermal conductivity for heat transfer. The composite structure allows optimization of each material's properties for its specific function.

Inventive Principle:
Principle #40Composite materials

3Temperature

If a network of channels is integrated into the housing, then thermal regulation efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvethermal regulation efficiencyVSAvoidhousing structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling channels are integrated directly into the housing structure itself, merging the structural and thermal management functions into a single component. This eliminates the need for separate cooling plates or attachments, reducing overall system complexity despite the intricate channel network.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing serves multiple functions simultaneously: structural containment, explosion resistance, and thermal management through integrated channels. This multi-functionality reduces the need for additional separate components, thereby simplifying the overall device architecture.

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

4Temperature

If the cooling liquid volume is increased to absorb more heat, then thermal absorption capacity is improved, but pressure losses in channels increase

Engineering Contradiction:
Improvethermal absorption capacityVSAvoidpressure losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The channels are designed with smooth curved transitions instead of sharp angles, reducing turbulence and pressure losses. The optimized flow paths minimize energy dissipation while allowing sufficient cooling liquid volume for effective heat absorption.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The channel dimensions, cross-sectional area, and flow velocity are optimized to balance thermal absorption capacity with pressure loss minimization. By adjusting these parameters, the system achieves effective cooling while maintaining efficient fluid circulation.

Inventive Principle:
Principle #35Parameter changes

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 effectively prevents thermal runaway propagation, ensuring secure battery operation in aircraft, meeting aeronautical standards, and preserving undamaged cells in case of adjacent cell failures, while maintaining mechanical integrity and efficient heat management.

Implementation Method 1

a network of channels 24 arranged in the main body 21 of the housing, comprising a plurality of channels 24 along the walls 220 of the cavities, for example, partially surrounding each cavity in which a cell is received, for cooling the cells contained in the cavities

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the channel network is sized so that the volume of liquid along each cavity is sufficient to absorb a determined quantity of heat energy corresponding to a safety threshold, considering a static volume of liquid

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

A battery protection device is proposed according to claim 1... the housing 20 includes a main body 21 comprising a set of partitions 22, the set of partitions 22 defining walls 220 delimiting cavities 23 open at at least one end to each receive a cell

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4165712B1Device for protecting and cooling a battery
Publication Date: 2023.11.08 AIRBUS DEFENCE & SPACE SAS
  • EP4165712B1 patent drawingFigure 1~2
  • EP4165712B1 patent drawingFigure 3~4
  • EP4165712B1 patent drawingFigure 5~6

AI summary

Proposed is a device (10) for protecting a battery, comprising a casing (20) suitable for containing a set of electrical energy storage cells of the battery, characterised in that the casing comprises: - a casing body that extends around the cells and comprises a set of partition walls (22) forming cavities (23), which are open at at least one end in order to each receive one of the cells, each cavity being delimited by a wall (220) intended to come into contact with one of the cells, and - at least one network of channels (24) running along the walls of the cavities, the channels being arranged in the partition walls and filled by a temperature control liquid, the network of channels containing the temperature control liquid having such dimensions that at least one predetermined volume of temperature control liquid runs along the wall of each cavity in order to be able to absorb a predetermined quantity of heat energy corresponding to a heat energy safety threshold.