Battery Module Thermal Switch Discharge for Runaway Containment

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Solution Overview

Problem

Existing battery modules face challenges in preventing thermal runaway propagation, particularly in aviation applications, where external heat sources can trigger thermal runaway in cells, and current safety features like fuses and circuit interrupt devices are inadequate.

Innovation Solution

Implementing a passive control system with thermal switches and load resistors in each cell to rapidly discharge the cell to a low state-of-charge when a temperature threshold is reached, preventing thermal runaway by reducing the cell's energy state and minimizing exothermic reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal management systems and software monitoring are used to prevent thermal runaway, then battery safety is improved, but device complexity and cost increase

Engineering Contradiction:
Improvebattery safetyVSAvoidthermal management system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the battery pack into modular units with individual containment features. Each battery cell or module is isolated within its own fire-resistant enclosure, creating segmented compartments that prevent thermal runaway propagation between adjacent cells. This segmentation approach maintains safety while avoiding the need for complex system-wide thermal management infrastructure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts and removes the flame and hot gas from the battery system by providing dedicated venting pathways that direct combustion products away from adjacent battery cells. The containment structure captures and isolates the thermal runaway event, preventing it from affecting other parts of the battery pack, thereby eliminating the need for active thermal management systems.

Inventive Principle:
Principle #2Taking out (Extraction)

2Quantity of substance

If battery density is increased to improve energy storage, then energy capacity is improved, but thermal runaway propagation risk increases

Engineering Contradiction:
Improveenergy capacityVSAvoidthermal runaway propagation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

High-density battery cells are divided into isolated compartments with fire-resistant barriers between them. This segmentation allows the battery pack to achieve high overall energy capacity while preventing thermal runaway in one cell from propagating to adjacent cells, thus resolving the contradiction between energy density and safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fire-resistant containment structures and thermal barriers serve as intermediary elements between adjacent high-density battery cells. These intermediaries absorb and block thermal energy transfer, allowing high-capacity cells to be packed closely together without increasing thermal runaway propagation risk.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 passive control system effectively prevents thermal runaway by rapidly discharging cells to a low state-of-charge, reducing the risk of exothermic reactions and ensuring compliance with aviation safety standards by preventing fragment and flame release.

Implementation Method 1

a fire-resistant containment structure that mechanically prevents the propagation of thermal runaway between adjacent battery cells

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4229708B1Systems and methods for mechanical prevention of thermal runaway propagation
Publication Date: 2026.04.15 ELECTRIC POWER SYSTEMS INC
  • EP4229708B1 patent drawingFigure 1
  • EP4229708B1 patent drawingFigure 2A
  • EP4229708B1 patent drawingFigure 2B

AI summary

A method of validating a battery module for flight can comprise: coupling an external heating source to the battery module, the battery module including a plurality of cells; gradually applying heat to the battery module via the external heating source, wherein a cell in the plurality of cells that exceeds a temperature threshold is rapidly discharged to a state-of-charge between 0% and 25%; and verifying no fragments and no flames are released outside the battery module