Battery Cell Disconnect Assembly Using Low-Temp Expanding Microparticles

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Solution Overview

Problem

Existing devices fail to reliably detect thermal runaway in electrochemical batteries early enough to prevent propagation, often triggering due to pressure or temperature increases at advanced stages, leading to unnecessary disconnections and potential total destruction.

Innovation Solution

A disconnection device using microparticles that expand at a temperature threshold below 150°C, causing deformation of a surrounding capsule and exerting pressure on a weakening zone to break the connection between electrochemical elements, and a short-circuiting device that connects terminals of opposite polarities using expanding microparticles within a conductive or non-conductive capsule.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If disconnection devices activate at high temperature thresholds, then thermal runaway detection is provided, but early detection and prevention capability is lost

Engineering Contradiction:
Improvethermal runaway detectionVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention lowers the activation threshold from high temperature (where thermal runaway is already advanced) to a specific temperature range (e.g., 130°C) that occurs earlier in the thermal runaway process. This enables timely detection and prevention before the situation becomes uncontrollable.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The microparticles are pre-configured to expand at a predetermined temperature threshold that occurs early in the thermal runaway process. This preliminary action enables the disconnection device to activate before thermal runaway progresses to dangerous stages, allowing preventive measures to be taken in advance.

Inventive Principle:
Principle #10Preliminary action

2Temperature

If expandable materials with high temperature thresholds are used, then thermal stability is maintained, but early thermal runaway detection capability is reduced

Engineering Contradiction:
Improvethermal stabilityVSAvoiddetection precision
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The invention precisely controls the expansion threshold of the microparticles to a specific temperature (e.g., 130°C) rather than using materials with high or indefinite thresholds. This precise parameter setting enables accurate detection of early thermal runaway while maintaining appropriate thermal stability below the threshold.

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

Enables early detection and prevention of thermal runaway by activating at lower temperatures, reducing unnecessary disconnections and effectively preventing the propagation of thermal runaway phenomena.

Implementation Method 1

microparticles (5) capable of expanding when their temperature reaches a threshold value, said threshold value being less than 150°C

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the expansion of the microparticles causes a deformation of the capsule, this deformation exerting pressure in the vicinity of said at least one weakening zone, the pressure causing a tear of said at least one weakening zone

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP4046233B1Disconnecting device and short circuiting device comprising a thermally activable element
Publication Date: 2024.05.22 SAFT GRP SA
  • EP4046233B1 patent drawingFigure 1a~2a
  • EP4046233B1 patent drawingFigure 2b~3

AI summary

A disconnection device, in particular for disconnecting two electrically connected electrochemical elements. The present invention also relates to a device for short-circuiting two electrodes of opposite polarity in an electrochemical element. The subject matter of the invention includes an assembly comprising: • a) a connecting part (3) and • b) a disconnection device (4), the disconnection device being intended to disconnect two electrochemical elements (1, 2) connected by the connecting part (3), the disconnection device (4) comprising: • i) microparticles (5) capable of expanding when their temperature reaches a threshold value, the threshold value being below 150°C, • ii) a capsule (4a, 4b) enclosing all of the microparticles (5), the capsule (4a, 4b) being arranged such that when the temperature of the microparticles (5) reaches the threshold value, the expansion of the microparticles disconnects the connection between the two electrochemical elements (1, 2).