Fiber-optics-based spectroscopic sensing of battery systems

Abstract

A battery sensing system and a method of battery sensing are disclosed. The system includes an optical system configured to provide and direct a light beam through a first optical fiber to one or more cells contained within a battery housing and an analyzer configured to obtain absorption / scattering, fluorescence and / or Raman spectra based on an interaction of the light beam with the one or more cells and provide information on a status of the one or more cells.

Description

FIBER-OPTICS-BASED SPECTROSCOPIC SENSING OF BATTERY SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 63 / 671,398, filed July 15, 2024, the entirety of which is incorporated herein by reference.GOVERNMENT SUPPORT

[0002] This inventio was made with government support under NM-80NSSC24M0163 awarded by the National Aeronautics and Space Administration. The government has certain rights in the invention.TECHNICAL FIELD

[0003] The present application relates generally to spectroscopic sensing, particularly to systems, devices, and method of fiber-optic-based-spectroscopic sensing of battery systems.BACKGROUND

[0004] In battery-based energy storage systems, storing and delivering the electrochemical energy in a safe, reliable, and predictable manner is vital for the success of the application and the premise for applying any new battery technologies for mobile or stationary energy storage systems. For these purposes, a battery management system is a component to manage and utilize the electrochemical energy. A typical battery management system monitors output electrochemical parameters such as voltage, capacity, and temperature, etc., to evaluate various battery operation parameters, such as state-of-charge (SOC), state of health (SOH), and possibility of thermal runaway. Monitoring the chemical information within the cells of practical battery packs has been a long-standing challenge.SUMMARY

[0005] According to examples of the present disclosure, a battery sensing system is disclosed. The system comprises an optical system configured to provide and direct a light beam to one or more cells contained within a battery housing and an analyzer configured to obtain absorption / scattering, fluorescence, and / or Raman spectra based on an interaction of the light beam with the one or more cells and provide information on a status of the one or more cells. The optical system comprises a light source, one or more collection optics, and an optical fiber to provide the light beam to the one or more cells. The light source comprises one or moreblue light emitting diodes, lasers, and broadband light. The status comprises chemical information within the one or more cells. The analyzer is configured to operate while the battery is in operation. The analyzer is configured to interpret chemical signatures of the one or more cells based on spectral signatures and evolution of spectral features are live-correlated with electrochemical parameters. The analyzer is configured to provide information related to a fundamental chemistry behind observed electrochemical properties and predict a health and a failure of the one or more cells based on the spectral features that are live-correlated.

[0006] According to examples of the present disclosure, a method for battery sensing is disclosed. The method comprises providing and directing a light beam to one or more cells contained within a battery housing by an optical system and obtaining absorption / scattering, fluorescence, and / or Raman spectra based on an interaction of the light beam with the one or more cells and providing information on a status of the one or more cells by an analyzer. The optical system comprises a light source, one or more collection optics, and an optical fiber to provide the light beam to the one or more cells. The laser source comprises one or more blue light emitting diodes, lasers, and broadband light. The status comprises chemical information within the one or more cells. The method further comprises operating the analyzer at the same time that the battery is in operation. The method further comprises interpreting, by the analyzer, chemical signatures of the one or more cells based on spectral signatures and correlating an evolution of spectral features with electrochemical parameters. In the method wherein providing, by the analyzer, information related to a fundamental chemistry behind observed electrochemical properties and predicting, by the analyzer, a health and a failure of the one or more cells based on the spectral features are correlated.BRIEF DESCRIPTION OF THE FIGURES

[0007] FIG. 1 shows a system of the fiber-optics-based spectroscopic sensing technology according to examples of the present disclosure.

[0008] FIG. 2 shows a system for Raman- or fluorescence-based spectroscopic sensing platform according to examples of the present disclosure.

[0009] FIG. 3 shows a system for absorption / scattering-based spectroscopic sensing according to examples of the present disclosure.

[0010] FIG. 4 shows a system for absorption / scattering-based spectroscopic sensing via a fiber circulator according to examples of the present disclosure.

[0011] FIG. 5 shows a system of the high-throughput fiber-optics-based spectroscopic sensing enabled by an optical switch according to examples of the present disclosure.

[0012] FIG. 6A and FIG. 6B show fluorescence spectra at a few selected voltage points of the first cycle according to examples of the present disclosure.

[0013] FIG. 7A, FIG. 7B, and FIG. 7C show evolution of (FIG. 7A) voltage profile, (FIG. 7B) in-cell fluorescence intensity, and (FIG. 7C) average wavelength of fluorescence spectra of a fiber-implanted Li1.3Nbo.3Mno.4O2 cell according to examples of the present disclosure.

[0014] FIG. 8A, FIG. 8B, and FIG. 8C show evolution of (FIG. 8A) voltage profile, (FIG. 8B) in-cell fluorescence intensity, and (FIG. 8C) average wavelength of fluorescence spectra of a fiber-implanted LiNio.8Mno.1Coo.1O2 cell according to examples of the present disclosure.DETAILED DESCRIPTION

[0015] A battery management system (BMS) is a component for safe, reliable, and effective utilization of electrochemical energy and an indispensable element of energy storage systems for space missions. A typical BMS monitors electrochemical parameters such as voltage, state-of-charge, and temperature etc. Monitoring the chemical information within the cells of practical battery packs, which holds the key to the performance of the cells and the pack, has been a long-standing challenge. Without such a capability, how chemical information, in which the properties of batteries are rooted, changes in the battery cells during their operation, will be an unanswerable question. It will subsequently pose a significant hindrance in understanding why unwanted battery incidents (e.g. voltage drop, capacity fading, sudden failure, etc.) happen and how these incidents can be predicted and prevented.

[0016] Among all methods of measuring the chemical properties of materials / molecules or a system, spectroscopy, either based on Raman, photoluminescence (e.g. fluorescence), or absorption / scattering, is the most feasible and effective approach with a high sensitivity and specificity. However, battery cells for realistic applications are a fully sealed system that intrinsically forbid measurements of chemical properties within the cells without interrupting the operation. Without the chemical information, how dynamics of physicochemical processes in batteries, in which the properties of the batteries are rooted, changes during cell operation will be an unanswerable question. It will subsequently pose a significant hindrance in understanding why unwanted battery incidents (e.g. voltage drop, capacity fading, etc.) happen and how these incidents can be predicted and prevented.

[0017] Optical -fiber-based probes are ideally suited to probe the chemical information inside of batteries. Optical fibers transmit light via the total reflection principle, realized via apure silica core (higher refractive index) and a fluorine-doped silica cladding (lower refractive index). Optical fibers are thin, ranging from tens - hundreds of pm, and have a high conformality to the surrounding subjects. In the past few years, there has been a significant amount of effort in using optical fibers to live-monitor physical parameters, such as temperature, pressure, and stress, in battery systems. However, directly using optical fiber to measure spectroscopy, either Raman, fluorescence, or absorption, inside batteries, has been very rare. Considering these advantages, using fiber-optics-based spectroscopic techniques, either Raman, fluorescence, and direction absorption, to probe chemical information in batteries is enriched with exciting opportunities to address the challenge of live-monitoring chemical processes associated with energy storage.

[0018] According to examples of the present disclosure, a fiber optics-based sensing technology is disclosed that enables live-collection of Raman, fluorescence, and absorption spectra in battery cells and live-correlation between electrochemical and spectroscopic properties. It can reveal the fundamental chemistry behind the observed electrochemical properties. This technology greatly advances the diagnosis and prognosis technology of battery systems and will render a transformative impact on mobile and stationary energy storage systems and photonic-based characterization technologies. The fiber-optics-based spectroscopic sensing platform could be based on three configurations.

[0019] FIG. 1 shows a system 100 of fiber-optics-based spectroscopic sensing technology according to examples of the present disclosure. The disclosed fiber optics-based sensing technology enables live-collection of absorption / scattering, fluorescence, and / or Raman spectra within battery cells. Fiber-optics-based spectroscopy has been well applied in many non-battery -related fields, such as optogenetics, in which activities of neuron are picked up and communicated by optical fibers implanted in organs. Similar to living systems, battery systems also strongly rely on complex chemical reactions in the cell and optical fibers are best suited to pick up and reveal the chemical information in the batteries. Optical fibers are known for their robustness, tolerance to harsh conditions, and reliability, allowing the applications in various conditions. Moreover, optical fibers are thin (~ 150 pm) and have a high conformality to the surrounding subjects, allowing feasible integration into various types of battery cells (e.g. cylindrical, pouch, etc.). In this technology, light source 102, such as one or more blue light emitting diodes, lasers, and / or broadband light, are applied as the excitation source for fluorescence and / or Raman spectra, respectively, through lens 104 and onto optical fiber 106 to probe an interior of battery 108, such as electrolyte 112 and / or electrode 114. Optical fiber 106 can be integrated within a housing of battery 108 to provide absorption / scattering,fluorescence or Raman sensingl lO based on the light from light source 102. The return light from battery 108 is then collected for analysis by excitation / collection optics 116. All spectral acquisition and battery operation can be operated synchronously. The chemical signatures interpreted based on the spectral signatures and the evolution of spectral features can be live- correlated with electrochemical parameters. The correlation can reveal the fundamental chemistry behind the observed electrochemical properties and finally predict the health and failure of cells and battery systems.

[0020] Fiber Optical Raman and Fluorescence-based Spectroscopic Sensing. FIG. 2 shows a system 200 for Raman- or fluorescence-based spectroscopic sensing platform according to examples of the present disclosure. Light source 202, such as a fiber-coupled laser, controlled by a computer-controlled shutter 204 and attenuator 206, is used as the excitation source for fluorescence and / or Raman spectra via optical fiber 208. Light source 202 can comprise a laser, which can be a laser, operable to produce a laser beam at one or more of the following wavelengths: such as 405 nm, 442 nm, 457 nm, 473 nm, 488 nm, 514 nm, 532 nm, 561 nm, 633 nm, 660 nm, 671 nm, 785 nm, 880 nm, 976 nm, 1064 nm. These wavelengths are just examples of the wavelengths that can be produced by light source 202. The light from optical fiber 208 is directed through lens 214 and onto beamsplitter or a dichroic beamsplitter 212 that is used to divert the laser beam and couple the laser beam used for laser excitation 218 into an optical fiber 216, which is implanted into battery or battery cell 220. Optical fiber 216 allows fiber end laser excitation 222 within excitation / collection cone 224 to probe side reaction products 226 inside of battery or battery cell 220, either in electrolyte, electrode, or electrolyte-electrode interphase. The excited optical signal 228 (e.g. fluorescence and / or Raman spectra) can be collected by optical fiber 216. After passing through lens 214 and beamsplitter / dichroic beamsplitter 212, the excited optical signals pass through a long-pass filter 210 for further filtering of excitation laser and are diverted, using beam splitter 236 and lens 238, to CMOS camera 240 and coupled, using beam splitter 236 and lens 242, into another optical fiber 244 connected to CCD-array spectrometer 246. CMOS camera 240 directly visualizes the surface of optical fiber 216 implanted into battery or battery cell 220, allowing fast and feasible optical beam alignment. CCD-array spectrometer 246 can directly reveal the fluorescence / Raman spectra excited by the light source 202. The power of light source 202 can be monitored by power monitor 232 based on light transmitted through beam splitter 212.

[0021] System 200, including fiber-coupling of the laser and measurement platform, has a small footprint, instead of relying on bulk-size lab benchtop-like microscopes and spectrometers. The small footprint and the modular design ensure the feasible application andtransportability of the system in various terrestrial / aerospace / aeronautic systems. The operation of system 200, including shutter control, spectra acquisition, image acquisition, and data processing, is fully automated by Python / Matlab codes, providing real-time monitoring of the spectroscopic status of battery 230.

[0022] Fiber Optical Absorption / Scattering-based Spectroscopic Sensing. FIG. 3 shows a system 300 for absorption / scattering-based spectroscopic sensing platform according to examples of the present disclosure. The example system 300 is similar to configuration shown in FIG. 2, except that the light source 302 is broadband, either in the visible or near infrared region. Also, the long pass filter 210 is not needed for filtering the excitation light. The broadband light from light source 302 is conducted into the battery 328, absorbed or scattered by the side reaction species in the battery 328, either electrode, electrolyte, or electrolyte-electrode interphase. The broadband light after absorption / scattering is collected by the optical fiber 316 and passes through the beamsplitter 312, visualized via the camera 340 and analyzed via the spectrometer 346. The camera 340 or the CCD detector 346 can be based on visible light analysis (i.e. Si-based) or near-infrared light analysis (i.e. InGaAs-based).

[0023] As shown in FIG. 3, light source 302, such as a fiber-coupled broadband light source, controlled by a computer-controlled shutter 304 and attenuator 306, is used as the excitation source for absorption / scattering via optical fiber 308. The light from optical fiber 308 is directed through lens 310 and onto beamsplitter or a dichroic beamsplitter 312 that is used to divert the light beam and couple the light beam used for broadband illumination 318 into an optical fiber 316, which is implanted into battery or battery cell 328. Optical fiber 316 allows fiber end laser excitation 322 within excitation / collection cone 324 to probe side reaction products 326 inside of battery or battery cell 328, either in electrolyte, electrode, or electrolyte-electrode interphase. The excited optical signal 328 (e.g. broadband after absorption / scattering) can be collected by optical fiber 316. After passing through lens 314 and beamsplitter / dichroic beamsplitter 312, the excited optical signals are reflected by beam splitter 336 and passes through lens 328 to CMOS camera 340, and coupled, using beam splitter 336 and lens 342, into another optical fiber 344 connected to CCD-array spectrometer 346. CMOS camera 340 directly visualizes the surface of optical fiber 316 implanted into battery or battery cell 328, allowing fast and feasible optical beam alignment. CCD-array spectrometer 346 can directly reveal the absorption / scattering spectra excited by the light source 302. The power of light source 302 can be monitored by power monitor 332 based on light transmitted through beam splitter 312.

[0024] It should be noted that the system of FIG. 2 and the system of FIG. 3 can be combined together to realize alternating Raman / fluorescence-based sensing and absorption / scattering-based sensing. It can be realized via having both laser and broadband light coupled into the same optical fiber. Raman / fluorescence-based sensing and absorption / scattering-based sensing can be switched by switching the light (i.e. laser or broadband) coupled into the optical fiber via optical shutters.

[0025] Fiber Optical Absorption / Scattering-based Spectroscopic Sensing-Based on fiber circulator.

[0026] FIG. 4 shows a system 400 for absorption / scattering-based spectroscopic sensing via a fiber circulator according to examples of the present disclosure. The configuration shown in FIG. 3 can be simplified by replacing the beamsplitter scheme, e.g., beamsplitter 312, 336, via fiber circulator 410. The broadband light 402, which is controlled by a shutter 404 and attenuator 406, is coupled into a fiber circulator 410. The broadband light is then diverted into battery or battery cell 414 via the fiber circulator 410 and the light after scattering / absorption is diverted into the spectrometer 418.

[0027] Fiber-optics switch for enabling multiple cell monitoring.

[0028] FIG. 5 shows a system 500 for high-throughput fiber-optics-based spectroscopic sensing enabled by an optical switch according to examples of the present disclosure. In some examples, the spectroscopic sensing of FIG. 1, FIG. 2, FIG. 3, and / or FIG. 4 can be integrated with optical switch technologies, schematically shown in FIG. 5, and greatly enhanced the throughput of the system. The basic platform shown in FIG. 2, FIG. 3, and FIG. 4 can only run one single cell at a time. To enable spectroscopic sensing of multiple battery cells, an optical switch can be integrated into the systems of FIG. 1, FIG. 2, FIG. 3, and / or FIG. 4, by coupling the input of optical switch 508 with the incident light and then mating the output of optical switch 508 with the optical fibers implanted into the batteries 514A, 514B, 514C, 514D, 514E, 514F, 514G, 514H . Such configuration enables multiple channels for the platform, similar to the multi-channel battery testing platform. It allows the system to select the cell to which the incident light 502 (either broadband or laser) is conducted. As the optical switch 508 is bidirectional, the excited spectra of the cell can be transported back to the platform by the optical switch 508. This configuration greatly enhances the efficiency of the system and its applicability when simultaneous multiple cell monitoring is needed. This addition is compatible with both Raman, photoluminescence, absorption / scattering-based spectroscopic sensing.

[0029] Type of optical fiber for in-battery implantation. The optical fiber implanted into the battery can be flexible in refractory index type (i.e. step-index or gradient index), size (25 um - 1000 um), numerical aperture number (i.e. NA value, 0.1, 0.22, 0.39, 0.50), cladding material (doped silica or fluoropolymer, etc.), and coating material (acrylate, polyimide, etc.).

[0030] Example of application of the systems. Understanding the Mn dissolution of Lii.3Nbo.3Mno.402-based Li-ion batteries via photoluminescence (i.e. fluorescence)-based sensing.

[0031] First, the systems, as discussed above, can be used to study the evolution of chemical information in Lii.3Nbo.3Mno.402-based Li-ion batteries. Li1.3Nbo.3Mno.4O2 is an emerging cathode material of Li-ion batteries, featuring a high energy density and earth abundant Mn-based chemistry. Because of these features, Li1.3Nbo.3Mno.4O2 has been under the spotlight in recent years. However, Mn-based cathode materials, including Li1.3Nbo.3Mno.4O2, are intrinsically susceptible to Mn dissolution issues. Understanding the relationship between Mn dissolution and electrochemistry is the key to solve this problem and optimize its performance. In terms of realistic applications, live-monitoring the status of Mn dissolution can reveal how healthy the battery is and provide key information for chemistry -based diagnosis and prognosis. Typically, dissolved Mn species in Li-ion battery electrolyte is fluorescent, making the developed platform ideally suited for investigation.

[0032] FIG. 6A and FIG. 6B show fluorescence spectra at a few selected voltage points of the first cycle according to examples of the present disclosure. The image of the optical fiber surface is also shown for direct visualization of the intensity of the fluorescence. At OCV (open circuit voltage) state, the fluorescence generated inside of the battery is very weak, demonstrated by both the weak spectral intensity and faint fluorescence image. During the first charge process, the fluorescence intensity gradually rises, suggesting the dissolution of Mn beings during the charge process. Such a process is also seen from the brighter fluorescence images during the first charge process. The intensity is maximized at the fully charged. Also, during the first charge process, the average wavelength is also subject to slight increase, from 540 nm at the OCV state to 561 nm at the fully charged state, reflected by the slight change of the color of the image (from greyish green 602 to yellowish green 604). During the first discharge process, the fluorescence intensity decreases and the intensity dims, minimized around ~ 3.0 V. When approaching the first fully discharged state (i.e. 1.5 V), the fluorescence intensity rises again. During this entire discharge process, the average wavelength slightly shifts from lower wavelength, from 567 nm to 560 nm, reflected by fluorescence image color change from yellowish green 606 to green 608. Such a highly dynamic process proves theeffectiveness of the fiber-optics-based approach in probing the chemical information of battery electrolyte inside of the battery.

[0033] FIG. 6A and FIG. 6B show fluorescence spectra collected in a Li1.3Nbo.3Mno.4O2 cell via the fiber-optics sensing platform at various (FIG. 6A) charged and (FIG. 6B) discharged conditions according to examples of the present disclosure. The microscope image of the optical fiber surface showing the fluorescence collected in the battery is also shown for direct visualization.

[0034] FIG. 7A, FIG. 7B, and FIG. 7C show evolution of (FIG. 7A) voltage profile, (FIG. 7B) in-cell fluorescence intensity, and (FIG. 7C) average wavelength of fluorescence spectra of a fiber-implanted Li1.3Nbo.3Mno.4O2 cell according to examples of the present disclosure.

[0035] Besides the first cycle, the measurement was extended to multiple cycles and correlated the battery voltage profile, fluorescence intensity, average wavelength of fluorescence statistically, as shown in FIG. 7A, FIG. 7B, and FIG. 7C. Such a correlation reveals a very clear picture of the Mn dissolution mechanism. In the first charged process, before reaching 4.2 V (first mark 702, FIG. 7A, FIG. 7B, and FIG. 7C), the onset of oxygen oxidation of Li1.3Nbo.3Mno.4O2, the fluorescence intensity largely remains unchanged. It suggests the electrode material is highly stable during the Mn3+-Mn4+oxidation in the first cycle. Upon the initiation of oxygen oxidation after 4.2 V, the fluorescence intensity starts to rise, suggesting oxygen oxidation triggers Mn dissolution. When the electrode is approaching the fully charged state, the electrode is at a highly polarized kinetic-controlled state. At this state, the oxygen loss of the electrode, either via direct oxygen gas release or decomposing the electrolyte solvent, releases a significant amount of Mn ions from the lattice, leading to Mn complex molecular ions with increasing concentration. It leads to a highly distinctive intensity maxima (first red mark), corresponding to the fully charged (i.e. also the most unstable) state in the voltage profile.

[0036] When the cell switches from a charge process to a discharge process, the electrode switches from the highly polarized kinetic-controlled state to a more thermodynamically stable state, reflected by the abrupt voltage drop from 4.8 V to 4.2 V within a short amount of time. Thus, starting from the onset of the discharge process, Mn dissolution and electrolyte decomposition is quickly suppressed. As the released Mn ions in electrolytes are spontaneously consumed by the reductive deposition of the Mn ions at the anode, the amount of free Mn complex molecular ions decreases considerably in the beginning of the discharge process. At ~ 2.5 V of the discharge process, the fluorescence intensity reaches alocal minimum (square mark 708). Further lowering the cell voltage toward 1.5 V leads to considerable formation of low valence (i.e. 2+) Mn ions on the surface, causing another rise of Mn dissolution into the electrolyte. Following the first cycle, the fluorescence intensity demonstrates a similar trend. A very obvious phenomenon is that the intensity quickly increases when approaching the fully charged state (circle marks 706), due to the strong tendency of oxygen loss and Mn dissolution. Also, as the cycle number increases, a general upward trend in intensity is observed, suggesting the Mn dissolved in electrolyte gradually accumulates with cycling. Apart from these clearly visible effects, a less apparent phenomenon is that local intensity minimums are observed with a regular pattern. By correlating with the voltage profile of the battery, it was found that the time periods when local intensity minimum appears (square marks 708) generally match the time periods of voltage plateaus. It suggests that Mn dissolution and electrolyte decomposition is greatly suppressed when a major bulk- phase reaction is in progress.

[0037] Besides the intensity evolution, the average wavelength of fluorescence spectra demonstrates an interesting evolution. A general trend is that the average wavelength shifts to higher wavelengths during discharge and shifts to lower wavelengths during discharge. The reason for the phenomenon can be that the LUMO energy of the fluorescent Mn complexes decreases / increases coherently with the higher / lower voltage. To put it differently, at a more electron-withdrawing potential field (i.e. higher voltage), the unfilled electronic states of the fluorescent complexes shift to lower energies. A major and obvious exception to this trend is that the average wavelength at the non-first-cycle fully charged states exhibit a “notch”, as shown in FIG. 7C at 710. The most likely reason for this effect is due to the oxygen release triggered reductive-like Mn dissolution, causing a brief lift of the LUM0-H0M0 energy gap. All the above-mentioned spectral evolution, data correlation, and mechanistic analysis strongly support the feasibility of the experimental approach and the power of fiber-optics-based spectroscopy-electrochemistry correlation.

[0038] Example of application of the systems. Application of the system for understanding the electrolyte properties of LiNio.sCoo.iMno.i Ch-based Li-ion batteries via photoluminescence (i.e. fluorescence)-based sensing.

[0039] FIG. 8A, FIG. 8B, and FIG. 8C show evolution of (FIG. 8A) voltage profile, (FIG. 8B) in-cell fluorescence intensity, and (FIG. 8C) average wavelength of fluorescence spectra of a fiber-implanted LiNio.8Mno.1Coo.1O2 cell according to examples of the present disclosure.

[0040] Besides Lii.sNbo.sMno^Ch-based Li-ion batteries, the disclosed fiber-opticsbased spectroscopic sensing technology was applied to LiNio.sCoo.iMno.iCh-based Li-ion batteries. It has been well known that LiNio.8Coo.1Mno.1O2 is the most successful Li-ion battery cathode materials to-date, as seen from its successful application in various high-end EVs and eVTOLs. Understanding the electrolyte chemical properties of LiNio.8Coo.iMno.i02-based batteries, i.e. the “blood” of these high energy batteries, holds great significance for fundamental energy science and realistic applications. FIG. 8A, FIG. 8B, and FIG. 8C show the evolution of electrochemical properties, fluorescence intensity, average wavelength of a fiber-implanted LiNio.8Coo.1Mno.1O2 cell for multiple cycles according to examples of the present disclosure.

[0041] With consecutive battery cycling, the fluorescence intensity and average wavelength demonstrate a highly correlated evolution pattern. The major trend is summarized as follows. For the first charge process, the fluorescence intensity change is largely minimal. When the voltage reaches the fully charged state (i.e. 4.4 V), the fluorescence intensity exhibits an abrupt increase (first mark 802). Upon discharge, for the first 2-4 cycles, the fluorescence intensity still presents local maxima (marks 804) when the cell switches from charge to discharge. As the cycle number increases, such a trend gradually diminishes, gradually replaced by sharp intensity maxima at the fully charged states (marks 806). Another obvious phenomenon is that, when the cell switches from discharge to charge, an abrupt intensity drop of fluorescence intensity is observed (red marks). Such an abrupt intensity drop is followed by a slow drop of fluorescence during charge, until the local intensity maxima prior to the fully charged state (marks 808). With consecutive cycling, the overall trend of the intensity is decreasing, unlike the increasing fluorescence of Lii.sNbo.sMno^CL-based cells. The fluorescence intensity evolution shows a strong correlation with the average wavelength evolution. The intensity spikes at the fully charged states match with a series of wavelength minima (marks 810) and the intensity abrupt drops at the fully discharged states match with a series of wavelength maxima (marks 812). The regularly appearing local intensity minima prior to the fully charged states match with a series of average wavelength maxima (marks 814). In recent years, although the energy storage mechanism of LiNio.8Coo.1Mno.1O2 has been under investigation via various spectroscopic approaches, the results shown in FIG. 8A, FIG. 8B, and FIG. 8C are distinctive compared to the existing studies, representing an “in-cell” investigation in real batteries.

[0042] The technology is enriched with great commercialization opportunities for the battery market, by providing a unique and smart method of system diagnosis and prognosis. Itis expected that the technology will find a strong application perspective for commercial battery packs, regardless of the chemistry of the battery cells (e.g. Li-ion, Na-ion, etc.). Thus, the technology is not limited to the scenario of a particular type of battery and can be widely applied in various applications, such as transportation, aerospace, and stationary energy storage.

[0043] The description of the different illustrative embodiments has been presented for purposes of illustration and description, and may be not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other illustrative embodiments. The embodiment or embodiments selected may be chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as may be suited to the particular use contemplated.

[0044] While the foregoing disclosure has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be clear to one of ordinary skill in the art from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the disclosure and may be practiced within the scope of the appended claims. For example, all the methods, systems, and / or component parts or other aspects thereof can be used in various combinations. All patents, patent applications, websites, other publications or documents, and the like cited herein are incorporated by reference in their entirety for all purposes to the same extent as if each individual item were specifically and individually indicated to be so incorporated by reference.

[0045] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein.

[0046] While the present teachings have been illustrated with respect to one or more implementations, alterations and / or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the present teachings may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of theother implementations as may be desired and advantageous for any given or particular function. As used herein, the terms “a”, “an”, and “the” may refer to one or more elements or parts of elements. As used herein, the terms “first” and “second” may refer to two different elements or parts of elements. As used herein, the term “at least one of A and B” with respect to a listing of items such as, for example, A and B, means A alone, B alone, or A and B. Those skilled in the art will recognize that these and other variations are possible. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” Further, in the discussion and claims herein, the term “about” indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the intended purpose described herein. Finally, “exemplary” indicates the description is used as an example, rather than implying that it is an ideal.

[0047] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompasses by the following claims.

[0048] The examples set forth herein represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

[0049] It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0050] Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like may be used herein for ease of description to describe the relationship of one component and / or feature to another component and / or feature, or other component(s) and / orfeature(s), as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation(s) depicted in the figures.

[0051] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Claims

What is claimed is:

1. A battery sensing system, the system comprising; an optical system configured to provide and direct a light beam through a first optical fiber to one or more cells contained within a battery housing; and an analyzer configured to obtain aborption / scattering, fluorescence and / or Raman spectra based on an interaction of the light beam with the one or more cells and provide information on a status of the one or more cells.

2. The system of claim 1, wherein the optical system comprises a light source, one or more collection optics, and a second optical fiber to provide the light beam to the one or more cells.

3. The system of claim 2, wherein the light source comprises one or more blue light emitting diodes, lasers, and broadband light sources.

4. The system of claim 1, further comprising an optical switch to provide switching the light beam to one or more additional batteries for sensing.

5. The system of claim 1, wherein the status comprises chemical information within the one or more cells.

6. The system of claim 1, wherein the analyzer is configured to operate while the battery is in operation.

7. The system of claim 1, wherein the analyzer is configured to interpret chemical signatures of the one or more cells based on spectral signatures and evolution of spectral features are live-correlated with electrochemical parameters.

8. The system of claim 7, wherein the analyzer is configured to provide information related to a fundamental chemistry behind observed electrochemical properties and predict a health and a failure of the one or more cells based on the spectral features that are live- correlated.

9. A method for battery sensing, the method comprising; providing and directing a light beam through a first optical fiber to one or more cells contained within a battery housing by an optical system; and obtaining absorption / scattering, fluorescence and / or Raman spectra based on an interaction of the light beam with the one or more cells and providing information on a status of the one or more cells by an analyzer.

10. The method of claim 9, wherein the optical system comprises a light source, one or more collection optics, and a second optical fiber to provide the light beam to the one or more cells.

11. The method of claim 10, wherein the light source comprises one or more blue light emitting diodes, lasers, and broadband light.

12. The method of claim 9, further comprising switching, by an optical switch, the light beam to one or more additional batteries for sensing.

13. The method of claim 9, wherein the status comprises chemical information within the one or more cells.

14. The method of claim 9, further comprising operating the analyzer at a same time that the battery is in operation.

15. The method of claim 9, further comprising interpreting, by the analyzer, chemical signatures of the one or more cells based on spectral signatures and correlating an evolution of spectral features with electrochemical parameters.

16. The method of claim 15, wherein providing, by the analyzer, information related to a fundamental chemistry behind observed electrochemical properties and predicting, by the analyzer, a health and a failure of the one or more cells based on the spectral features that are correlated.

17. A battery sensing system, the system comprising;an optical system configured to provide and direct a light beam through a first optical fiber to one or more cells contained within a plurality of battery housings; an optical switch for switching the light beam to each of the plurality of battery housings; and an analyzer configured to obtain absorption / scattering, fluorescence and / or Raman spectra based on an interaction of the light beam with the one or more cells of each of the plurality of battery housing and provide information on a status of the one or more cells of each of the plurality of battery housings.

18. The battery sensing system of claim 17, wherein the status comprises chemical information within the one or more cells of each of the plurality of battery housings.

19. The system of claim 17, wherein the analyzer is configured to operate while each of the battery housing are in operation.

20. The system of claim 17, wherein the analyzer is configured to interpret chemical signatures of the one or more cells based on spectral signatures and evolution of spectral features are live-correlated with electrochemical parameters.

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