Multispectral Impedance Measurement for Battery Cell Isolation
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Solution Overview
Problem
There is a long-felt need to integrate near real-time broadband impedance measurements into battery management systems (BMS) to enhance battery diagnostics, as conventional systems primarily sense voltage, current, or temperature.
Innovation Solution
The development of an in-line rapid impedance measurement device and methods for performing in-line fast impedance spectroscopy, utilizing a switch network operable under a switching algorithm, to rapidly perform targeted impedance measurements on battery packs, modules, or cells, and to isolate individual cells to distinguish between non-repeatable and repeatable deviant impedance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery management systems use voltage, current, or temperature sensing, then the system complexity is low, but the diagnostic capability is insufficient
Solution Approach 1:
The patent transitions from conventional voltage, current, and temperature sensing to impedance spectroscopy measurements. By changing the measurement parameter from simple electrical quantities to complex impedance across multiple frequencies, the system gains enhanced diagnostic capability to detect battery health, degradation, and failure modes while managing the increased complexity through efficient measurement algorithms.
2Measurement precision
If broadband impedance measurements are performed across all cells, then measurement precision is improved, but the measurement time increases
Solution Approach 1:
The patent divides the battery pack into individual cell segments and performs impedance measurements selectively. Instead of measuring all cells simultaneously or sequentially across the entire pack, the system segments the measurement process to focus on specific cells or groups based on diagnostic needs, thereby reducing total measurement time while maintaining precision for critical cells.
Solution Approach 2:
The implementation uses periodic impedance measurements at selected frequency points rather than continuous broadband sweeping. By periodically sampling impedance at strategic frequencies and using equivalent circuit modeling to interpolate full broadband characteristics, the system achieves accurate diagnostic information with significantly reduced measurement time compared to traditional broadband spectroscopy.
3Loss of information
If impedance measurements are performed on the entire battery pack, then the measurement coverage is complete, but the ability to isolate individual cell defects is reduced
Solution Approach 1:
The patent extracts individual cell impedance data from the overall pack measurement by using switching networks to isolate specific cells during measurement. This extraction capability allows the system to obtain both pack-level and cell-level impedance information, enabling precise defect localization to individual cells while maintaining efficient measurement throughput through selective isolation rather than measuring every cell in every measurement cycle.
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 solution enables rapid, broadband AC impedance measurements, providing advanced diagnostics and prognostics capabilities for battery health assessment, allowing for the identification of failing cells within a pack or module and enabling timely interventions.
Implementation Method 1
Impedance (Z) extends the concept of resistance (Q) to alternating current (AC) circuits and possesses both magnitude and phase
Data Source
AI summary
An in-line rapid impedance measurement device and methods of performing in-line rapid impedance spectroscopy including a switch network operable under a switching algorithm useful to rapidly perform targeted impedance measurements to assess state of health, defect or failure of battery packs or modules having a plurality of electrochemical cells interconnected in series or parallel and to isolate individual cells within a pack or module to distinguish between non-repeatable anomalous impedance measurements from repeatable deviant impedance measurements and identify the source of deviant impedance measurements.