Piezoelectric Battery Separator for Dendrite Detection

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Solution Overview

Problem

Current lithium-ion batteries lack a reliable method to detect the presence of metallic dendrites, which can lead to catastrophic failures due to internal shorts, particularly in rugged applications, and there is a need for improved safety and lifespan monitoring.

Innovation Solution

The implementation of an electrical device and method that monitors the electric field within the battery's separator material using piezoelectric sensors to detect changes in electric field intensity, allowing for early detection of dendrite formation and prevention of internal shorts through a battery management system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If piezoelectric separator elements are added to enable dendrite detection, then battery safety and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvebattery safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the separator element's mechanical function with a sensing function by incorporating piezoelectric material into the separator. This merging allows the separator to simultaneously perform its primary role of preventing dendrite-induced shorts and its secondary role of detecting dendrite formation through piezoelectric signal generation when mechanically stressed by growing dendrites.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The separator element is designed to serve multiple functions: it acts as both a physical barrier between electrodes and a sensing element for dendrite detection. The piezoelectric material enables the separator to detect mechanical deformations caused by dendrite growth while maintaining its primary separation function, thus achieving multi-functionality without adding separate dedicated sensing components.

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

2Measurement precision

If pulse generation and comparison circuits are added for dendrite detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedendrite detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the battery's own operational pulses (charging/discharging cycles) as the test signal source. The controller generates a test pulse during normal battery operation and compares it with the piezoelectric separator's response signal. This self-service approach eliminates the need for external dedicated test equipment while maintaining detection precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The dendrite detection is performed periodically by injecting test pulses at specific intervals during battery charging/discharging cycles. The controller applies periodic test pulses and compares the piezoelectric separator's response signals at these intervals, enabling continuous monitoring without requiring constant active measurement, thus balancing precision with system simplicity.

Inventive Principle:
Principle #19Periodic action

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 approach enhances battery safety by enabling the detection of dendrite growth before it causes a short, providing insights into the battery's health and state over time, and can be implemented relatively inexpensively within existing designs using capacitance measurement techniques.

Implementation Method 1

a dielectric piezoelectric separator element disposed between the first conductive electrode and the second conductive electrode and configured to provide a second pulse

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2991135B1Methods for dendrite detection and devices for batteries and dendrite sensors
Publication Date: 2018.10.03 LOCKHEED MARTIN CORP
  • EP2991135B1 patent drawingFigure 1
  • EP2991135B1 patent drawingFigure 2
  • EP2991135B1 patent drawingFigure 3~5

AI summary

An electrical device is provided. The electrical device includes a pulse generator configured to generate a first pulse. The electrical device also includes a battery. The battery includes a first conductive electrode configured to receive the first pulse from the pulse generator, a second conductive electrode coupled to the first conductive electrode, and a dielectric separator element coupled to the first conductive electrode and the second conductive electrode and configured to provide a second pulse. The second pulse is based on the first pulse and based on the electrical properties of the dielectric separator element. The electrical device also includes a controller coupled to the pulse generator and the dielectric separator element. The controller is configured to compare the first pulse with the second pulse.