Li-Ion Battery Surface Strain Gauges for Local Degradation Detection

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Solution Overview

Problem

Conventional methods for determining lithium-ion battery degradation only monitor pressure variations across the entire principal surface, failing to identify specific positions of maximum volume expansion, which is crucial for improving battery safety and performance.

Innovation Solution

A degradation-determination system comprising at least four pressure detecting units installed on the battery surfaces, which detect pressure at corresponding installation positions and a degradation determining unit that estimates the coordinates of the maximum volume expansion position based on measured values from these units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure monitoring is performed across the entire principal surface to determine battery degradation, then degradation detection capability is provided, but the ability to locally identify specific positions of maximum volume expansion is lost

Engineering Contradiction:
Improvedegradation detection capabilityVSAvoidlocal position information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent divides the battery surface into multiple discrete measurement zones by installing pressure detecting units at specific positions (corners and center of each surface). This segmentation allows the system to capture localized pressure variations while maintaining overall degradation monitoring capability, thereby identifying both general degradation status and specific local expansion positions.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If only overall pressure variation is monitored, then the system remains simple, but the ability to identify local degradation positions is lost

Engineering Contradiction:
Improvesystem simplicityVSAvoidlocal position identification
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges global degradation monitoring with local position identification by combining pressure detecting units at multiple strategic positions. The degradation determining unit integrates pressure data from all positions to simultaneously assess overall battery degradation status and identify specific local expansion positions, achieving both functions without requiring separate complex systems.

Inventive Principle:
Principle #5Merging (Combining)

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 local identification of battery degradation positions, improving safety and performance by accurately determining the coordinates of maximum volume expansion, thereby facilitating targeted maintenance and charging control.

Implementation Method 1

at least four pressure detecting units that are installed on one or more surfaces of the secondary battery and each of which is configured to detect pressure of a battery surface at a corresponding installation position

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP3817127B1Degradation determination system and degradation determination method for secondary battery
Publication Date: 2025.04.23 MINEBEAMITSUMI INC
  • EP3817127B1 patent drawingFigure 1
  • EP3817127B1 patent drawingFigure 2~3
  • EP3817127B1 patent drawing

AI summary

A degradation-determination system includes at least four strain gauges that are installed on a principal surface of a lithium-ion battery and each of which is configured to detect pressure of a battery surface at a corresponding installation position, and a degradation determining unit configured to determine degradation of the lithium-ion battery based on measured values at the strain gauges. The degradation determining unit is configured to estimate a maximum expansion position where volume expansion is maximal in a region defined by the strain gauges, of the surface of the lithium-ion battery.