System and method for magnetic resonance mapping of physical and chemical changes in conducting structures
Inventors
Jerschow, Alexej • ILOTT, Andrew J. • MOHAMMADI, Mohaddese • SILLETTA, Emilia • ROMANENKO, Konstantin
Assignees
Publication Number
US-12352711-B2
Publication Date
2025-07-08
Expiration Date
2036-04-14
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Abstract
A method of diagnosing a conducting structure includes providing the conducting structure in a magnetic field, immersing the conducting structure in a detection medium, or placing a detection medium in the vicinity of the conducting structure, exciting nuclear or electronic spins within the detection medium using a broad-band excitation pulse, receiving an NMR or ESR spectrum from the detection medium, obtaining a frequency distribution of the detection medium, and indirectly measuring internal characteristics of the conducting structure by characterizing frequency changes in the frequency distribution. Conducting structures are analyzed on the basis of changes in magnetic susceptibilities and internal electric current distributions, which may change over the course of a charging/discharging cycle, and a result of degradation and failure of the conducting structure. The conducting structure may be, for example, a battery, a capacitor, a supercapacitor, a fuel cell, or a catalyst material.
Core Innovation
The invention provides a method and system for diagnosing internal characteristics of conducting structures, such as batteries, capacitors, supercapacitors, fuel cells, or catalyst materials, by using magnetic resonance to indirectly measure their properties. The conducting structure is placed in a magnetic field and immersed in or surrounded by a detection medium containing nuclear or electronic spins. These spins are excited with an electromagnetic signal, and an NMR or ESR spectrum is received from the detection medium. By obtaining frequency distributions from the detection medium and characterizing changes in these frequency distributions, the internal chemical and physical changes within the conducting structure can be indirectly detected without requiring radiofrequency access inside the device.
The problem addressed arises from the difficulty of applying conventional magnetic resonance techniques to commercial batteries and other conducting structures due to their encasement in conductive materials that are opaque to radiofrequency fields. Existing methods often require special cell designs or destructive analysis, which are time-consuming, costly, and may alter the information during disassembly. There is a need for improved technology capable of nondestructively and rapidly measuring the state of charge, current distributions, and defects in conducting structures within typical commercial configurations.
This invention solves the problem by indirectly measuring the magnetic field variations in the detection medium caused by magnetic susceptibility changes, permanent magnetism, and internal electric current distributions within the conducting structure. These changes reflect oxidation state variations, charge distribution, and material inhomogeneities during operation. The method includes modeling susceptibilities or currents within the conducting structure to fit measured frequency distributions in the surrounding medium. The approach enables non-invasive, fast, and spatially resolved monitoring of conductors even when enclosed in conductive materials, thereby offering diagnostics of state of charge, defects, and operational behaviors.
Claims Coverage
The claims include multiple independent claims directed to systems and non-transitory computer-readable media configured to diagnose internal characteristics of conducting structures by exciting and receiving electromagnetic signals from a detection medium external to the structure and modeling internal changes based on magnetic susceptibility or current distributions.
Indirect detection of internal characteristics using a detection medium
The system excites nuclear or electronic spins in a detection medium external to the conducting structure in a magnetic field, obtains frequency distributions of the detection medium at different times, and detects frequency changes to indirectly measure internal characteristics of the conducting structure.
Modeling internal characteristics based on current distributions
Internal characteristics are modeled by assigning one or more regions within the conducting structure given current distributions and calculating generated magnetic fields affecting the detection medium; parameters are fit by minimizing differences between calculated and measured frequency distributions.
Modeling internal characteristics based on magnetic susceptibility differences
Internal characteristics are modeled by assigning one or more regions within the conducting structure given magnetic susceptibilities and calculating generated magnetic fields impacting the detection medium; susceptibilities are fit by minimizing differences between calculated and measured frequency distributions.
System components for diagnosis
Includes a magnet to generate the magnetic field, at least one radiofrequency coil positioned within the magnet, and a holder configured to receive the conducting structure, which may include separate detection medium chambers on either side of a conducting structure chamber.
Use of various detection media and conducting structures
The detection medium may be water, oil, trimethyl silane, or water doped with a paramagnetic species. The conducting structure can be a battery, capacitor, supercapacitor, fuel cell, or catalyst material.
Measurement of state of charge through frequency distribution
The system or media include processors configured to measure the state of charge of the conducting structure by converting frequency distributions of the detection medium into a state of charge.
The claims cover systems and methods utilizing magnetic resonance excitation and measurement of an external detection medium to indirectly determine internal properties of conducting structures by modeling frequency changes according to current distributions or magnetic susceptibilities, incorporating components such as magnets, radiofrequency coils, holders with detection medium, and various materials, enabling noncontact diagnosis and state of charge measurement.
Stated Advantages
Enables nondestructive, noncontact diagnosis of conducting structures even when encased in conductive materials.
Permits in situ and operando measurement of state of charge, internal current distributions, and detection of defects.
Provides a fast and spatially resolved method for analyzing chemical and physical changes inside commercial batteries.
Allows sensitive detection of oxidation state changes via magnetic susceptibility variations.
Uses indirect measurement through detection medium to overcome radiofrequency penetration limitations.
Potential for high-throughput and automated analysis with machine learning to classify defects.
Enhances diagnostic capability for battery health, performance, and production quality control.
SPRITE imaging enables distortion-free visualization in presence of strong local magnetic fields.
Method applicable to various conducting structures beyond batteries, including capacitors and catalysts.
Documented Applications
Non-invasive diagnosis and state of charge determination of batteries, including lithium-ion pouch cells and commercial cells.
Mapping internal current distributions within batteries during charge and discharge cycles.
Detection and localization of physical and chemical defects inside battery cells and catalyst materials.
Monitoring degradation and failure mechanisms in electrochemical devices in situ.
Rapid quality control and screening of cells during manufacturing including unfinished cells.
Magnetic resonance mapping in supercapacitors, fuel cells, and catalyst materials.
Use of SPRITE imaging for distortion-free magnetic field mapping in batteries containing strongly magnetic components.
Potential use in devices incorporating batteries, such as cell phones, where the entire device can be analyzed.
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