Separator Air Permeability Measurement for Shutdown Temperature Detection

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Solution Overview

Problem

Existing methods for determining the shut-down and melt-down temperatures of separators in lithium secondary batteries are inaccurate and require the preparation of a coin cell and use of electrolyte, which can vaporize during safety tests.

Innovation Solution

A system that directly measures the air permeability of separators to determine shut-down and melt-down temperatures using an air permeability-determining unit, heating units, and a controlling unit to calculate these temperatures based on temperature and air permeability data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separator is used in an electrolytic cell to prevent mixing of electrolyte solutions, then separation efficiency is improved, but the separator may undergo shutdown or meltdown at extreme temperatures causing operational failure

Engineering Contradiction:
Improveseparator operational reliabilityVSAvoidtemperature extremes affecting separator
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by determining specific temperature thresholds (shutdown temperature and meltdown temperature) that characterize the separator's behavioral boundaries. By measuring and establishing these temperature parameters, the system can predict and prevent separator failure before it occurs, transforming the separator from a passive component vulnerable to temperature extremes into a monitored system with known operational limits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by continuously monitoring the separator's temperature and comparing it against the predetermined shutdown and meltdown temperatures. When the separator temperature approaches these critical thresholds, the system provides feedback signals that trigger alerts or automated responses, allowing operators to take corrective action before the separator fails, thus improving reliability under temperature stress.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If extreme temperatures cause shutdown or meltdown of the separator, then cell operation is disrupted, but traditional methods cannot accurately measure these critical temperatures

Engineering Contradiction:
Improvecritical temperature measurementVSAvoidseparator temperature at extreme conditions
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses an intermediary approach by placing temperature sensors in contact with the separator to indirectly measure its temperature. Rather than attempting to measure the separator's temperature directly under extreme conditions, the system uses sensors as intermediaries that can safely and accurately detect temperature at the separator's location, enabling precise measurement of critical temperatures without exposing measurement equipment to damaging conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical or contact-based measurement methods with electronic temperature sensing technology. By using electronic sensors and digital measurement systems, the patent achieves precise temperature measurement at critical points without the limitations of mechanical gauges, enabling accurate detection of shutdown and meltdown temperatures that were previously difficult or impossible to measure.

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

3Object-affected harmful factors

If the separator shuts down or melts down at extreme temperatures, then harmful substances can mix and contaminate each other, but prevention mechanisms are lacking

Engineering Contradiction:
Improvesubstance mixing and contaminationVSAvoidseparator integrity under temperature stress
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by establishing predetermined shutdown and meltdown temperature thresholds before extreme temperature events occur. These pre-established temperature limits serve as preventive boundaries that trigger protective actions before the separator actually fails. By setting these thresholds in advance and monitoring against them, the system prevents harmful substance mixing by taking corrective action before the separator's structural integrity is compromised.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent implements beforehand cushioning by creating a safety buffer between normal operating temperatures and the separator's critical shutdown and meltdown temperatures. Through continuous monitoring and early warning systems, the patent cushions against temperature extremes by providing advance notice and allowing gradual response, preventing sudden catastrophic failure and substance contamination that would occur without such protective margins.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 system allows for precise and rapid determination of shut-down and melt-down temperatures without the need for a coin cell or electrolyte, providing high accuracy and reproducibility.

Implementation Method 1

wherein the first sensor is configured to detect a shutdown temperature of the separator, and the second sensor is configured to detect a meltdown temperature of the separator

Methodology Applied
Scientific EffectPhase change (liquid to solid): Phase Change

Implementation Method 2

wherein the first sensor is configured to detect a shutdown temperature of the separator, and the second sensor is configured to detect a meltdown temperature of the separator

Methodology Applied
Scientific EffectPhase change (solid to liquid): Phase Change

Data Source

PatentEP4134646B1System for measuring shutdown temperature and meltdown temperature of separator
Publication Date: 2026.04.08 LG ENERGY SOLUTION LTD
  • EP4134646B1 patent drawingFigure 1
  • EP4134646B1 patent drawingFigure 2
  • EP4134646B1 patent drawingFigure 3~4

AI summary

The present disclosure relates to a system for determining the shut-down temperature and melt-down temperature of a separator. The system includes a jig having a through-hole, a heating unit, a temperature sensor, a controlling unit and an air permeability-determining unit. In this manner, it is possible to provide a novel system for determining the shut-down temperature and melt-down temperature of a separator by using the air permeability (Gurly value) of the separator.