In-situ Battery Monitoring via RF Impedance Reflectometry

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Solution Overview

Problem

Aircraft batteries with advanced Lithium-ion chemistries face electrolyte instabilities at elevated temperatures, making it difficult to accurately assess battery health and risk of failure using traditional state of charge (SOC) measurements based on voltage and temperature alone.

Innovation Solution

An in-situ battery monitoring system that injects RF or high-frequency test signals into battery cells to measure impedance behavior, combining this data with temperature and SOC assessments to detect anomalies and predict potential failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional state of charge (SOC) measurements based on voltage and temperature are used, then the measurement method is simple, but the measurement precision of battery health assessment is insufficient

Engineering Contradiction:
Improvebattery health assessment accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an RF signal as an intermediary to probe the battery's internal impedance characteristics. The RF signal interacts with the cathode-anode assembly and electrolyte, providing indirect information about battery health that complements direct voltage and temperature measurements, thereby improving assessment accuracy without requiring complex internal sensors

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional electrical measurement methods with RF electromagnetic field-based impedance measurement. By using RF signals to excite the battery and measuring the resulting impedance response, the system obtains more comprehensive health information that goes beyond what conventional voltage and temperature sensors can provide

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

2Use of energy by moving object

If advanced Lithium-ion chemistries with higher energy densities are used, then the energy density increases, but the stability of the battery decreases due to electrolyte instabilities

Engineering Contradiction:
Improveenergy densityVSAvoidbattery stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent performs preliminary detection of electrolyte instabilities and internal anomalies using RF impedance measurement before they develop into critical failures. By continuously monitoring impedance changes at elevated temperatures, the system can identify early signs of degradation and take preventive actions, allowing the battery to operate safely at higher energy densities

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where RF impedance measurements are continuously compared against baseline values and thresholds. When impedance changes indicate electrolyte instability or internal degradation, the system provides feedback that can trigger alerts or control actions to prevent failure, thereby maintaining reliability alongside high energy density operation

Inventive Principle:
Principle #23Feedback

3Reliability

If comprehensive battery health assessment including RF impedance measurement is implemented, then the reliability of battery operation improves, but the device complexity increases

Engineering Contradiction:
Improvebattery operation safetyVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the RF monitoring system to serve multiple functions: impedance measurement, anomaly detection, localization, and health assessment. By making the system multi-functional, the patent reduces the need for separate dedicated systems for each function, thereby improving reliability without proportionally increasing overall system complexity

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

Solution Approach 2:

The patent divides the battery into multiple monitorable segments or zones by using RF signal reflection and impedance variation at different locations. This segmentation allows targeted monitoring of specific high-risk areas (such as individual cells or connections) rather than requiring comprehensive monitoring of the entire battery system, reducing complexity while maintaining safety

Inventive Principle:
Principle #1Segmentation

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

Provides a comprehensive assessment of battery health by identifying risks of short circuits and other structural issues, enhancing safety by preventing venting and fire risks through continuous monitoring of cathode-anode assembly integrity.

Implementation Method 1

use reflectometry to measure the relative in-situ radio frequency (RF) impedance behavior of the cathode-anode assemblies within the battery cells

Methodology Applied
Scientific EffectReflectometry: Reflection

Implementation Method 2

measure the relative in-situ radio frequency (RF) impedance behavior

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentEP2787360B1In-situ battery monitoring system
Publication Date: 2022.06.29 THE BOEING CO
  • EP2787360B1 patent drawingFigure 1
  • EP2787360B1 patent drawingFigure 2
  • EP2787360B1 patent drawingFigure 3A~3C

AI summary

The present disclosure provides a system (170) and method for battery (140) monitoring. The disclosed method involves injecting (120, 130) at least one test signal into the battery, and receiving (150, 160) at least one response signal from the battery. The response signal(s) comprises at least one reflected signal. The method further involves comparing, with at least one processor (110), the response signal(s) with at least one baseline signal to produce at least one comparison signal. Also, the method involves detecting, with at least one processor, at least one anomaly within the battery by using the comparison signal(s). Further, the method involves determining, with at least one processor, a location at least one anomaly within the battery by using the comparison signal(s).