A battery lithium precipitation and dendrite growth detection system and method, battery and battery pack

Abstract

This application discloses a battery lithium plating and dendrite growth detection system, method, battery, and battery pack, relating to the field of battery safety monitoring technology. The detection system includes: a fiber optic sensing module with a fiber optic surface plasmon resonance sensing probe extending into the battery cell and positioned between the negative electrode and the separator, for acquiring resonance wavelength signals; a temperature compensation module with a stress-free fiber optic grating temperature sensor deployed inside the battery cell, for acquiring internal temperature signals; a spectral calculation module for receiving the above two signals, fusing the signals, and extracting spectral feature parameters; and a graded early warning module for determining the stage of lithium plating and dendrite growth at the negative electrode interface based on a comparison of the spectral feature parameters with a preset threshold, and outputting a corresponding level of early warning signal. This application achieves non-electrical signal sensing through in-situ fiber optic sensing, solving the problems of missed lithium plating detection and delayed early warning in traditional technologies, thus improving battery safety.

Description

Technical Field

[0001] This application relates to the field of battery safety monitoring technology, and in particular to a battery lithium plating and dendrite growth detection system, method, battery, and battery pack. Background Technology

[0002] With the development of digital operation and maintenance in the new energy vehicle industry, the accuracy of battery lifecycle safety monitoring data has gradually become a key concern. In existing technologies, the lithium plating state inside the battery is mainly determined by monitoring voltage anomalies through the battery management system or by offline imaging methods such as X-rays and CT scans. However, these methods generally suffer from problems such as missed lithium plating detection and delayed early warnings, making it difficult to meet the needs of battery lifecycle safety monitoring.

[0003] In practical applications of battery safety monitoring, existing methods often suffer from signal lag and false alarms due to either difficulty in capturing microscopic changes in ion concentration at the negative electrode interface through indirect characterization or inability to simultaneously perform in-situ real-time monitoring due to offline detection. Significant deviations can lead to inaccurate safety control conclusions, increase disassembly and verification costs, or even trigger safety accidents, thereby reducing the service safety of battery packs and the efficiency of research and development verification. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a battery lithium plating and dendrite growth detection system, method, battery and battery pack that can solve the problems of missed lithium plating detection and delayed early warning.

[0005] In a first aspect, embodiments of this application provide a battery lithium plating and dendrite growth detection system, the battery lithium plating and dendrite growth detection system comprising: The fiber optic sensing module includes a fiber optic surface plasmon resonance sensing probe encapsulated in an electrolyte-resistant capillary. The fiber optic surface plasmon resonance sensing probe extends into the cell and is positioned between the negative electrode plate and the separator. The fiber optic surface plasmon resonance sensing probe is externally connected to a fiber optic signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface. The temperature compensation module includes a stress-free fiber optic temperature sensor installed inside the battery cell to acquire the internal temperature signal of the battery cell. The spectral calculation module receives the resonance wavelength signal and the temperature signal, fuses the two signals to eliminate the wavelength drift component caused by temperature, and extracts spectral feature parameters. The graded early warning module is used to determine the stage of lithium plating and dendrite growth at the negative electrode interface based on the comparison results of the spectral characteristic parameters and preset thresholds, and output an early warning signal of the corresponding level.

[0006] In one possible implementation, the fiber optic surface plasmon resonance sensing probe includes: Single-mode optical fiber, with the sensing end face treated by grinding and polishing; A gold film is deposited on the polished end face of a single-mode fiber to excite the surface plasmon resonance effect. An electrolyte-resistant capillary is sleeved around the periphery of the single-mode optical fiber, with the end face of the single-mode optical fiber located at the end face of the electrolyte-resistant capillary or extending outward therefrom, so that the gold film can contact the electrolyte. A sealing structure is provided to fill the gap between the electrolyte-resistant capillary and the single-mode optical fiber, as well as the junction between the end face of the electrolyte-resistant capillary and the single-mode optical fiber, for the purpose of blocking the electrolyte.

[0007] By adopting the above technical solution, through the electrolyte-resistant capillary sealing structure and the single-mode fiber end-face gold film design, the optical path is ensured to be open while achieving electrolyte isolation and protection, thereby improving the corrosion resistance and long-term operational stability of the sensing probe inside the battery.

[0008] In one possible implementation, the fiber surface plasmon resonance sensing probe and the stress-free fiber grating temperature sensor are connected in series on the same fiber optic bus and operate in different wavelength channels to transmit the resonant wavelength signal and the temperature signal respectively based on the same optical path.

[0009] By adopting the above technical solution, the sensing and temperature measurement signals are integrated into the same optical fiber bus, which reduces the number of internal fiber leads in the battery, simplifies the packaging process, and reduces signal transmission loss.

[0010] In one possible implementation, the spectral calculation module is specifically used for: The temperature sensitivity coefficient and refractive index sensitivity coefficient of the optical fiber surface plasmon resonance sensing probe were pre-calibrated. Based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, a decoupling relationship between temperature and refractive index is constructed. Using the temperature signal, the wavelength shift component caused by temperature is separated and subtracted from the resonant wavelength signal to obtain the resonant wavelength shift caused only by the change in ion concentration at the negative electrode interface and lithium metal deposition.

[0011] By adopting the above technical solution, a dual-coefficient decoupling algorithm based on temperature sensitivity and refractive index sensitivity is used to eliminate the interference of ambient temperature fluctuations on optical signals, thereby improving the purity and accuracy of lithium plating detection data.

[0012] In one possible implementation, the spectral characteristic parameters include the resonant wavelength shift, the minimum reflectance, and the full width at half maximum (FWHM); the spectral calculation module is further used for: Based on the reflection spectrum acquired and demodulated by the fiber optic signal demodulator, the reflection value at the point of lowest reflectance is determined as the minimum reflectance value. On either side of the point of lowest reflectivity, find the two wavelengths corresponding to the point where the reflectivity rises to half the sum of the minimum reflectivity and one. Define the interval between the two wavelengths as the full width at half maximum (FWHM).

[0013] By adopting the above technical solution and defining the minimum reflectance and the full width at half maximum (FWHM) calculation method, the quantitative extraction of the peak shape characteristics of surface plasmon resonance spectrum was realized, providing a data basis for identifying the spectral broadening effect caused by dendrite growth.

[0014] In one possible implementation, the hierarchical early warning module pre-stores a multi-level threshold mapping table calibrated based on the lithium plating evolution law; The graded early warning module determines whether the current state is characterized by no lithium plating, initial deposition, dendrite formation, or short circuit risk by comparing the spectral feature parameters with the multi-level threshold mapping table. The initial deposition state is determined by the resonance wavelength drift reaching a first warning threshold; the dendrite formation state is determined by the resonance wavelength drift reaching a second warning threshold, the resonance wavelength drift rate reaching a rate threshold, the minimum reflectance being lower than a first lower limit threshold, and the full width at half maximum (FWHM) of the reflection spectrum exceeding a preset broadening threshold; the short-circuit risk state is determined by the resonance wavelength drift reaching a third warning threshold, the minimum reflectance being lower than a second lower limit threshold, and the full WHM of the reflection spectrum exceeding a preset broadening threshold.

[0015] Using the above technical solution, a multi-level threshold mapping table is calibrated based on the evolution law of lithium plating. By jointly determining the resonance wavelength drift, drift rate, minimum reflectivity, and full width at half maximum (FWHM), a multi-stage classification of no lithium plating, initial deposition, dendrite formation, and short-circuit risk is achieved.

[0016] In one possible implementation, the graded early warning module is further used to perform joint discrimination based on cell operating condition information, and to configure discrimination logic differently according to the charging stage: During the constant current charging phase, when the resonant wavelength drift rate exceeds the reference rate threshold under the corresponding charging rate, a warning signal for the initial deposition state is triggered. During the constant voltage charging stage, when the resonant wavelength drift increases in the opposite direction and the increase exceeds the preset fluctuation threshold during the natural decrease of current, a warning signal for the dendrite formation state or the short circuit risk state is triggered. During the resting phase, when the amount of resonant wavelength drift decreases less than the value at the end of constant voltage charging compared to the value at the end of constant voltage charging, a warning signal for the dendrite formation state or the short circuit risk state is triggered. The cell operating condition information includes at least one of voltage, current, temperature, state of charge, and number of cycles.

[0017] By adopting the above technical solution, combining voltage, current, temperature, state of charge and number of cycles, and adapting to the differentiated discrimination logic of constant current, constant voltage and resting stages, false alarms caused by operating condition fluctuations are filtered out, and the confidence of the warning results under different charging scenarios is improved.

[0018] Secondly, embodiments of this application also provide a method for detecting lithium plating and dendrite growth in batteries, the method comprising the following steps: An optical fiber surface plasmon resonance sensing probe is inserted into the cell and positioned between the negative electrode plate and the separator. The optical fiber surface plasmon resonance sensing probe is connected to an external optical fiber signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface. The internal temperature signal of the battery cell is obtained by using a stress-free fiber optic grating temperature sensor deployed inside the battery cell. The resonant wavelength signal and temperature signal are received by the spectral calculation module, the two signals are fused to eliminate the wavelength drift component caused by temperature and extract spectral feature parameters; The graded early warning module uses the comparison results of the spectral characteristic parameters and preset thresholds to determine the stage of lithium plating and dendrite growth at the negative electrode interface, and outputs the corresponding level of early warning signal.

[0019] Thirdly, embodiments of this application also provide a smart battery, including a battery cell, a packaging shell, and a battery lithium plating and dendrite growth detection system as described in any possible implementation of the first aspect; wherein, the battery cell includes a negative electrode sheet, a separator, and an electrolyte; and the packaging shell is used to encapsulate the battery cell.

[0020] Fourthly, embodiments of this application also provide a battery pack, the battery pack including a plurality of smart batteries as described in the third aspect.

[0021] The battery lithium plating and dendrite growth detection system, method, battery, and battery pack provided in this application embodiment acquire the surface plasmon resonance wavelength signal at the negative electrode interface through an optical fiber sensing module and acquire the internal temperature signal of the battery cell through a temperature compensation module. The two signals are fused to eliminate the wavelength drift component caused by temperature and extract spectral feature parameters to determine the stage of lithium plating and dendrite growth at the negative electrode interface and output a corresponding level of warning signal, thereby improving battery safety.

[0022] To make the above-mentioned objects, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This illustration shows one of the functional block diagrams of a battery lithium plating and dendrite growth detection system provided in an embodiment of this application; Figure 2 This illustrates a second functional block diagram of another battery lithium plating and dendrite growth detection system provided in an embodiment of this application; Figure 3 A flowchart of a battery lithium plating and dendrite growth detection method provided in an embodiment of this application is shown; Figure 4 A flowchart of another battery lithium plating and dendrite growth detection method provided in an embodiment of this application is shown.

[0024] Explanation of key component symbols: In the diagram: 110 - Fiber optic sensing module; 120 - Temperature compensation module; 130 - Spectral calculation module; 140 - Graded early warning module; 150 - Communication interface module. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0026] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] To enable those skilled in the art to utilize the content of this application, and in conjunction with the specific application scenario of "power battery safety monitoring," the following implementation methods are provided. Those skilled in the art can apply the general principles defined herein to monitoring scenarios of other electrochemical devices without departing from the spirit and scope of this application.

[0028] The systems, methods, smart batteries, or battery packs described in the embodiments of this application can be applied to any scenario requiring monitoring of battery status. The embodiments of this application do not limit the specific cell chemistry system or application environment, and any detection scheme using the embodiments of this application is within the scope of protection of this application.

[0029] It is worth noting that, prior to this application, research has found that in the existing technology, mainstream battery monitoring solutions generally adopt single-dimensional electrical signal inference or offline observation methods. Various monitoring signals are independent of each other and lack a fusion processing mechanism, resulting in lagging monitoring results that are difficult to reflect the true internal state and cannot support the active protection requirements in high-safety scenarios.

[0030] Based on this, embodiments of this application provide a battery lithium plating and dendrite growth detection system, method, battery, and battery pack. The system acquires the surface plasmon resonance wavelength signal at the negative electrode interface through an optical fiber sensing module and the internal temperature signal of the battery cell through a temperature compensation module. A spectral calculation module fuses the two signals to eliminate temperature-induced wavelength drift components and extract spectral characteristic parameters. A graded early warning module determines the stage of lithium plating and dendrite growth based on the spectral characteristic parameters and outputs a corresponding level of early warning signal. This improves the safety management capability throughout the battery's entire lifecycle under limited wiring resources.

[0031] To facilitate understanding of this application, the technical solutions provided in this application will be described in detail below with reference to specific embodiments.

[0032] Please see Figure 1 , Figure 1 This is one of the functional block diagrams of a battery lithium plating and dendrite growth detection system provided in an embodiment of this application.

[0033] like Figure 1 As shown in the embodiment of this application, the battery lithium plating and dendrite growth detection system includes: an optical fiber sensing module 110, a temperature compensation module 120, a spectral calculation module 130, and a graded early warning module 140.

[0034] The fiber optic sensing module 110 includes a fiber optic surface plasmon resonance sensing probe encapsulated in an electrolyte-resistant capillary. The fiber optic surface plasmon resonance sensing probe extends into the battery cell and is positioned between the negative electrode plate and the separator. The fiber optic surface plasmon resonance sensing probe is externally connected to a fiber optic signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface.

[0035] Here, the fiber optic sensing module 110 emits probe light to the fiber optic surface plasmon resonance sensing probe via a fiber optic signal demodulator and receives the reflected light signal returning from between the negative electrode and the separator. By performing spectral analysis on the reflected light signal, the surface plasmon resonance wavelength signal is obtained. The resonance wavelength signal is the wavelength corresponding to the lowest reflectance in the reflection spectrum, directly reflecting the interface composite refractive index, and is sensitive to ion concentration and lithium deposition.

[0036] Here, the fiber optic surface plasmon resonance sensing probe provided in this embodiment is encapsulated with an electrolyte-resistant capillary, possessing the ability to withstand electrolyte corrosion inside the battery cell, thereby maintaining the stability of the probe during long-term operation inside the battery cell. The fiber optic surface plasmon resonance sensing probe is disposed between the negative electrode plate and the separator to obtain the interface refractive index change signal at that location.

[0037] The temperature compensation module 120 includes a stress-free fiber optic temperature sensor installed inside the battery cell to acquire the internal temperature signal of the battery cell.

[0038] Here, a stress-free fiber Bragg grating temperature sensor detects the ambient temperature inside the battery cell and converts the temperature change into a wavelength drift signal of the fiber Bragg grating, which is then output as the temperature signal. This provides an accurate reference data source for subsequent temperature drift interference elimination.

[0039] The spectral calculation module 130 is used to receive the resonance wavelength signal and the temperature signal, fuse the two signals to eliminate the wavelength drift component caused by temperature and extract spectral feature parameters.

[0040] Here, the spectral processing module 130 acquires the resonant wavelength signal and the temperature signal through an optical fiber signal demodulator, ensuring the alignment of the two signals on the time axis. The spectral processing module 130 performs synchronous processing and fusion on the acquired two signals to eliminate the wavelength drift component caused by temperature and extract spectral characteristic parameters reflecting the state of the negative electrode interface. In this way, the interference of ambient temperature fluctuations on the optical signal can be eliminated, improving the purity of the lithium plating detection data.

[0041] The graded early warning module 140 is used to determine the stage of lithium plating and dendrite growth at the negative electrode interface based on the comparison results of the spectral characteristic parameters and the preset threshold, and output an early warning signal of the corresponding level.

[0042] Here, the graded early warning module 140 receives the spectral feature parameters output by the spectral calculation module 130 and compares them with a preset threshold; based on the comparison result, it determines the current stage of lithium plating and dendrite growth at the negative electrode interface and generates an early warning signal of the corresponding level.

[0043] In this embodiment, the battery lithium plating and dendrite growth detection system includes an optical fiber sensing module 110, equipped with an optical fiber surface plasmon resonance sensing probe extending into the battery cell and positioned between the negative electrode sheet and the separator, for acquiring resonance wavelength signals; a temperature compensation module 120, equipped with a stress-free fiber optic grating temperature sensor deployed inside the battery cell, for acquiring internal temperature signals; a spectral calculation module 130, for receiving the above two signals, fusing the signals, and extracting spectral feature parameters; and a graded early warning module 140, for determining the stage of lithium plating and dendrite growth at the negative electrode interface based on the comparison results of the spectral feature parameters and a preset threshold, and outputting a corresponding level of early warning signal. This application achieves non-electrical signal sensing through in-situ optical fiber sensing, solving the problems of missed lithium plating detection and delayed early warning in traditional technologies, and improving battery safety.

[0044] In one possible implementation, the fiber optic surface plasmon resonance sensing probe includes: a single-mode fiber, a gold film, an electrolyte-resistant capillary, and a sealing structure. The sensing end face of the single-mode fiber is polished; the gold film is deposited on the polished end face of the single-mode fiber to excite the surface plasmon resonance effect. The electrolyte-resistant capillary is sleeved around the periphery of the single-mode fiber, with the end face of the single-mode fiber located at or extending outward from the end face of the electrolyte-resistant capillary, allowing the gold film to contact the electrolyte; the sealing structure fills the gap between the electrolyte-resistant capillary and the single-mode fiber, and at the junction of the end face of the electrolyte-resistant capillary and the single-mode fiber, to block the electrolyte.

[0045] Here, single-mode fiber refers to single-mode silica fiber.

[0046] In one alternative implementation, the cladding diameter of the single-mode fiber can be set to... The core diameter can be set to 9 The sensing end face of the single-mode optical fiber is sequentially made of 15mm thick material. 9 3 1 and 0.5 The grinding discs are used to grind and polish the end face to make it flat, smooth and perpendicular to the fiber axis.

[0047] The gold film is deposited on the polished fiber end face using a magnetron sputtering process.

[0048] In one alternative implementation, the base vacuum level of magnetron sputtering can be better than... The sputtering power can be set to 50W-100W, the deposition rate can be set to 0.1nm / s-0.2nm / s, and the gold film thickness can be controlled between 45nm-55nm.

[0049] In one alternative implementation, a 2nm-5nm chromium or titanium transition layer can be deposited on the polished end face of the single-mode fiber before gold film deposition to improve the adhesion between the gold film and the fiber end face.

[0050] Electrolyte-resistant capillary tubes are made of stainless steel or glass.

[0051] In one alternative implementation, the capillary inner diameter can be set to 150. -200 The outer diameter can be set to 0.3mm-0.5mm, and the length can be set to 5mm-10mm. The end face of the single-mode optical fiber extends 0-0.2mm beyond the end face of the capillary tube, so that the end face of the gold film is basically flush with or slightly exposed to the end face of the capillary tube.

[0052] The sealing structure uses electrolyte-resistant UV-curable epoxy resin to fill the gaps and junctions between the electrolyte-resistant capillary and the single-mode optical fiber.

[0053] In one alternative implementation, an electrolyte-resistant UV-curable adhesive can be used for sealing and curing.

[0054] In this way, the electrolyte-resistant capillary encapsulation and sealing structure effectively blocks electrolyte erosion and protects the gold film sensitive structure, improving the long-term stability of the fiber surface plasmon resonance sensing probe inside the battery cell. At the same time, the smooth outer wall of the electrolyte-resistant capillary can reduce mechanical damage to the diaphragm and electrode.

[0055] In one possible implementation, the fiber optic surface plasmon resonance sensing probe is arranged on the interface between the negative electrode surface and the diaphragm, with the sensor end face facing the negative electrode surface and a distance of 0.1mm-0.5mm from the negative electrode surface, and the sensor axis parallel to the negative electrode surface.

[0056] Here, during the cell stacking or winding process, the optical fiber surface plasmon resonance sensing probe is positioned in the spatial region where lithium dendrites first form. The optical fiber surface plasmon resonance sensing probe is fixed by the stacking clamping force or winding tension, so that the detection light field directly acts on the starting position of lithium deposition and dendrite growth.

[0057] This allows for the immediate detection of abrupt changes in the interfacial refractive index during the initial dendrite nucleation stage, improving the timeliness of early lithium plating detection.

[0058] It should be understood that the above-mentioned dimensions and material parameters are only specific examples of this application, and those skilled in the art can make adaptive adjustments to the cladding diameter, gold film thickness, and capillary size according to the actual specifications of the battery cell.

[0059] In one possible implementation, multiple fiber optic surface plasmon resonance sensing probes can be set up for large-capacity single cells or battery packs.

[0060] Here, multiple optical fiber surface plasmon resonance sensing probes can share the same optical fiber bus through wavelength division multiplexing or time division multiplexing technology, or they can be led out independently; multiple probes are arranged in different regions inside the cell, including local hot spots where lithium plating is prone to occur.

[0061] In this way, by deploying multiple points, it is possible to cover multiple high-risk areas where lithium dendrites may germinate, avoid blind spots in single-point monitoring, and improve the reliability and spatial resolution of the detection results.

[0062] In one possible implementation, the stress-free fiber optic temperature sensor is arranged in a stress-free location inside the cell, including the edge of the diaphragm or the root of the tab.

[0063] Here, the stress-free fiber Bragg grating temperature sensor is positioned at the aforementioned location to avoid mechanical compression of the fiber Bragg grating caused by electrode expansion or winding tension during the charging and discharging process of the battery cell, thereby preventing measurement errors introduced by stress.

[0064] This ensures that the wavelength drift signal acquired by the stress-free fiber optic temperature sensor is caused only by temperature changes, thus improving the accuracy of temperature measurement.

[0065] In one possible implementation, the stress-free fiber grating temperature sensor and the fiber surface plasmon resonance sensing probe are connected in series on the same fiber optic bus, and the two operate in different wavelength channels to transmit the resonant wavelength signal and the temperature signal respectively based on the same optical path.

[0066] Here, the operating wavelength of the optical fiber surface plasmon resonance sensing probe is set to around 1550nm; the center wavelength of the stress-free fiber grating temperature sensor is set to around 1560nm; the optical fiber signal demodulator has a built-in wavelength division multiplexing unit to separate the two signals according to the wavelength difference.

[0067] This reduces the number of internal fiber leads in the battery cell and enables synchronous monitoring of refractive index and temperature using the same fiber optic bus.

[0068] In one possible implementation, the fiber optic signal demodulator continuously acquires the reflection spectrum at a sampling rate of 1Hz-100Hz and extracts the resonant wavelength. and minimum reflectivity Simultaneously, the center wavelength change measured by the stress-free fiber optic temperature sensor is acquired through another channel or in a time-division manner. .

[0069] Here, the fiber optic signal demodulator includes a broadband light source, a fiber optic circulator, a spectral analysis unit, and a photodetector; the wavelength range of the broadband light source is 1200nm-1700nm to cover the SPR resonance peak; the fiber optic circulator is used to separate incident light and reflected light; the spectral analysis unit includes a grating spectrometer or a tunable filter; and the photodetector is used to convert optical signals into electrical signals.

[0070] This provides a high spatiotemporal resolution base data source for the spectral calculation module 130.

[0071] In one possible implementation, the stress-free fiber optic temperature sensor is only sensitive to temperature.

[0072] For example, the temperature sensitivity coefficient based on a stress-free fiber optic grating temperature sensor The relationship between wavelength shift and temperature change can be obtained using the following formula, which reflects the characteristic that fiber gratings are only sensitive to temperature:

[0073] in, The change in center wavelength measured by a stress-free fiber optic grating temperature sensor. The temperature sensitivity coefficient of the stress-free fiber optic temperature sensor. This represents the change in temperature.

[0074] In one possible implementation, the spectral calculation module 130 pre-calibrates the temperature sensitivity coefficient and refractive index sensitivity coefficient of the optical fiber surface plasmon resonance sensing probe; based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, a temperature-refractive-index decoupling relationship is constructed; using the temperature signal, the wavelength drift component caused by temperature is separated and subtracted from the resonant wavelength signal to obtain the resonant wavelength drift caused only by the change in ion concentration at the negative electrode interface and lithium metal deposition.

[0075] Here, the spectral calculation module 130 obtains the temperature sensitivity coefficient and the refractive index sensitivity coefficient by injecting a calibration liquid with a known refractive index or by conducting a temperature control experiment; based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, a decoupling expression is established; the temperature signal is substituted into the decoupling expression to calculate the wavelength drift component caused by temperature; and the wavelength drift component caused by temperature is removed from the resonant wavelength signal.

[0076] For example, based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, the resonant wavelength shift can be calculated using the following formula. This formula eliminates the coupling effect of temperature changes on the surface plasmon resonant wavelength signal through double-coefficient decoupling:

[0077] in, The total resonant wavelength drift is the amount measured by the surface plasmon resonance sensing probe of the optical fiber. The refractive index sensitivity coefficient, The change in refractive index This is the temperature sensitivity coefficient. The temperature change is the amount of data collected by the stress-free fiber optic temperature sensor.

[0078] In this way, the dual-coefficient decoupling algorithm can accurately isolate the cross-sensitivity effect of temperature and refractive index, thereby improving the accuracy of spectral feature parameter extraction.

[0079] In one possible implementation, the spectral characteristic parameters include the resonant wavelength shift, the minimum reflectance, and the full width at half maximum (FWHM). The spectral calculation module is further configured to: determine the reflectance value at the point of lowest reflectance as the minimum reflectance based on the reflectance spectrum acquired and demodulated by the fiber optic signal demodulator; and on both sides of the point of lowest reflectance, find the two wavelengths corresponding to the point where the reflectance rises to half the sum of the minimum reflectance and one, and define the interval between the two wavelengths as the full WHM.

[0080] Here, the spectral calculation module 130 performs peak-finding processing on the reflectance spectrum after subtracting the wavelength shift component caused by temperature, and locates the point of lowest reflectance to determine the resonant wavelength. and minimum reflectivity Based on the minimum reflectance value, calculate the reflectance increase to ( The left wavelength corresponding to +1) / 2 and right wavelength The difference between the right wavelength and the left wavelength It has been determined to be half-height full-width FWHM.

[0081] This enables the quantitative extraction of key features of the reflectance spectrum, providing standardized data input for graded early warning.

[0082] In one possible implementation, lithium ions are reduced and deposited on the surface of the negative electrode during charging. When the deposition is uniform, the ion concentration gradient near the interface is stable, and the refractive index changes slowly. Once localized non-uniform deposition occurs, local ion depletion leads to a sudden change in the interface refractive index. At the same time, the dielectric constant of lithium metal itself differs significantly from that of the electrolyte, and its accumulation alters the resonance conditions, manifested as a change in the resonance wavelength. Drift occurs, minimum reflectivity Things have changed.

[0083] Here, the spectral calculation module 130 extracts characteristic parameters from the reflectance spectrum after deducting the wavelength drift component caused by temperature, based on the above physical correlation.

[0084] For example, based on the reflectance spectrum after subtracting the wavelength shift component caused by temperature, the spectral calculation module 130 can extract spectral feature parameters in the following way, which can obtain feature information reflecting the multi-physical dimensions of lithium dendrite growth, specifically including: Resonant wavelength The wavelength corresponding to the lowest reflectance in the reflectance spectrum is a direct reflection of the interface composite refractive index and is sensitive to ion concentration and lithium deposition. Resonance wavelength shift The calculation formula is This reflects the cumulative amount of change in refractive index; Minimum reflectivity The reflectance value at the resonance peak is related to absorption and scattering near the gold film surface; an increase in lithium dendrites will decrease it. ; Full width at half maximum (FWHM) is the half-width at half-maximum of the resonance peak, reflecting the interface uniformity. Dendritic growth leads to peak broadening. Drift rate For a unit of time The change in reflects the dendrite growth rate.

[0085] This will provide multi-dimensional data support for subsequent tiered early warning systems.

[0086] In one possible implementation, the graded early warning module 140 pre-stores a multi-level threshold mapping table calibrated based on the lithium plating evolution law; the graded early warning module 140 determines whether the current state is a non-lithium plating state, an initial deposition state, a dendrite formation state, or a short-circuit risk state by comparing the spectral feature parameters with the multi-level threshold mapping table.

[0087] Here, the multi-level threshold mapping table is preset with a first warning threshold, a second warning threshold, a third warning threshold, a rate threshold, a first lower limit threshold, a second lower limit threshold, and a preset broadening threshold; the graded warning module 140 monitors the evolution trend of the spectral feature parameters in real time; When the resonant wavelength drift reaches the first warning threshold, it is determined that the current state is in the initial deposition stage; When the resonant wavelength drift reaches the second warning threshold, the resonant wavelength drift rate reaches the rate threshold, the minimum reflectivity is lower than the first lower limit threshold, and the full width at half maximum exceeds the preset broadening threshold, it is determined that the current state is dendrite formation. When the resonant wavelength drift reaches the third warning threshold, the minimum reflectivity is lower than the second lower limit threshold, and the full width at half maximum (FWHM) exceeds the preset widening threshold, it is determined that the current state is in a short-circuit risk state.

[0088] In this way, based on the joint criteria of multi-dimensional characteristic parameters, we can distinguish the different risk levels of lithium and dendrite growth, and avoid misjudgment by a single parameter.

[0089] In one possible implementation, the graded early warning module 140 is further used to perform joint discrimination by combining cell operating condition information and to configure discrimination logic differently according to the charging stage.

[0090] Here, the graded early warning module 140 acquires cell operating condition information, which includes at least one of voltage, current, temperature, state of charge, and number of cycles; the graded early warning module 140 adaptively switches the discrimination logic according to the current charging stage: During the constant current charging stage, the graded early warning module 140 focuses on the resonant wavelength drift rate. When the resonant wavelength drift rate exceeds the reference rate threshold under the corresponding charging rate, an early warning signal for the initial deposition state is triggered. During the constant voltage charging stage, the graded early warning module 140 focuses on the reverse growth characteristics of the resonant wavelength drift. When the resonant wavelength drift increases in the reverse direction during the natural decrease of current and the increase exceeds the preset fluctuation threshold, an early warning signal for the dendrite formation state or the short circuit risk state is triggered. During the resting phase, the graded early warning module 140 focuses on the characteristics of the resonant wavelength drift reduction. When the resonant wavelength drift reduction is less than the value at the end of constant voltage charging, an early warning signal for the dendrite formation state or the short circuit risk state is triggered.

[0091] In this way, by introducing cell operating condition information and contextual constraints of the charging stage, environmental interference and false signals can be effectively filtered out, thereby improving the accuracy of the early warning system.

[0092] Please see Figure 2 , Figure 2 This is the second functional block diagram of a battery lithium plating and dendrite growth detection system provided in another embodiment of this application. This embodiment mainly optimizes the transformation from single-cell early warning to battery pack safety control.

[0093] like Figure 2 As shown in the embodiment of this application, the battery lithium plating and dendrite growth detection system includes: The system includes an optical fiber sensing module 110, a temperature compensation module 120, a spectral calculation module 130, a graded early warning module 140, and a communication interface module 150. The connection relationship and functional description of the optical fiber sensing module 110, temperature compensation module 120, spectral calculation module 130, and graded early warning module 140 can refer to the relevant content of the aforementioned system embodiment and can achieve the same technical effect, so they will not be described in detail here.

[0094] The graded early warning module 140 is connected to the communication interface module 150. The communication interface module 150 is used to interface with an external battery management system to forward the early warning signal output by the graded early warning module 140 to the battery management system, triggering the battery management system to execute a graded response.

[0095] Here, if microscopic lithium plating anomalies at the single-cell level are not addressed in time, they can easily evolve into thermal runaway at the battery pack level. By adding a communication interface module 150 as a signal bridge between the detection system and the battery management system, the communication interface module 150 sends warning signals to the battery management system, and the battery management system executes specific control actions, thus realizing a closed loop from sensing to control.

[0096] Specifically, the graded early warning module 140 is configured to output early warning signals to the communication interface module 150; the communication interface module 150 is configured to interface with an external battery management system and forward the early warning signals to the battery management system; the battery management system is configured to execute corresponding safety strategies based on the level of the received early warning signals: when an early warning signal of initial deposition state is received, data is recorded and relevant personnel are alerted through the dashboard; when an early warning signal of dendrite formation state is received, the charging rate is limited or the charging power is reduced; when an early warning signal of short circuit risk state is received, the high-voltage circuit is disconnected.

[0097] For example, the limiting charging rate can be set to be reduced to below 0.2C.

[0098] In this way, by linking the communication interface module 150 with the external battery management system, the microscopic abnormal signals of a single cell are transformed into battery pack safety protection actions, effectively blocking the evolution path from local lithium plating to systemic thermal runaway, and improving the safety of the battery pack under high-risk operating conditions.

[0099] Based on the same application concept, this application also provides a battery lithium plating and dendrite growth detection method corresponding to the battery lithium plating and dendrite growth detection system provided in the above embodiments. Since the principle of solving the problem by the method in this application is similar to that of the battery lithium plating and dendrite growth detection system in the above embodiments of this application, the implementation of the method can be referred to the implementation of the method, and the repeated parts will not be described again.

[0100] like Figure 3 As shown, Figure 3 A flowchart illustrating a method for detecting lithium plating and dendrite growth in a battery, provided as an embodiment of this application. The method includes the following steps: S310. Insert the fiber surface plasmon resonance sensing probe into the cell and position it between the negative electrode plate and the separator. Connect the fiber surface plasmon resonance sensing probe to an external fiber signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface.

[0101] Here, a probe light is emitted to the fiber optic surface plasmon resonance sensing probe using a fiber optic signal demodulator, and the reflected light signal returned from between the negative electrode and the diaphragm is received; the surface plasmon resonance wavelength signal is obtained by performing spectral analysis on the reflected light signal.

[0102] The specific implementation method, technical details and technical effects of step S310 can be found in the relevant description of the fiber optic sensing module 110 in the system embodiment, and will not be repeated here.

[0103] S320: Use a stress-free fiber optic grating temperature sensor installed inside the battery cell to obtain the internal temperature signal of the battery cell. Here, a stress-free fiber optic temperature sensor installed inside the battery cell is used to sense the ambient temperature and convert the temperature change into a wavelength drift signal to output the temperature signal.

[0104] The specific implementation method, technical details and technical effects of step S320 can be found in the description of the temperature compensation module 120 in the system embodiment for deploying sensors and acquiring temperature signals, and will not be repeated here.

[0105] S330: Receive the resonant wavelength signal and temperature signal, fuse the two signals to eliminate the wavelength drift component caused by temperature and extract spectral feature parameters; Here, the surface plasmon resonance wavelength signal and the temperature signal are acquired by an optical fiber signal demodulator; the two acquired signals are processed to eliminate the wavelength drift component caused by temperature and extract spectral characteristic parameters reflecting the state of the negative electrode interface.

[0106] The specific implementation method, technical details and technical effects of step S330 can be found in the relevant description of the spectral calculation module 130 in the system embodiment, and will not be repeated here.

[0107] S340. Based on the comparison results between the spectral characteristic parameters and the preset threshold, determine the stage of lithium plating and dendrite growth at the negative electrode interface, and output a warning signal of the corresponding level.

[0108] Here, the spectral characteristic parameters are compared with preset thresholds, and the stage of lithium plating and dendrite growth at the negative electrode interface is determined based on the comparison results, and a corresponding warning signal is generated.

[0109] The specific implementation method, technical details and technical effects of step S340 can be found in the description of the threshold comparison, judgment stage and output warning signal of the graded warning module 140 in the system embodiment, and will not be repeated here.

[0110] In one possible implementation, the fiber optic surface plasmon resonance sensing probe includes: Single-mode optical fiber, with the sensing end face treated by grinding and polishing; A gold film is deposited on the polished end face of a single-mode fiber to excite the surface plasmon resonance effect. An electrolyte-resistant capillary is sleeved around the periphery of the single-mode optical fiber, with the end face of the single-mode optical fiber located at the end face of the electrolyte-resistant capillary or extending outward therefrom, so that the gold film can contact the electrolyte. A sealing structure is provided to fill the gap between the electrolyte-resistant capillary and the single-mode optical fiber, as well as the junction between the end face of the electrolyte-resistant capillary and the single-mode optical fiber, for the purpose of blocking the electrolyte.

[0111] In one possible implementation, the fiber surface plasmon resonance sensing probe and the stress-free fiber grating temperature sensor are connected in series on the same fiber optic bus and operate in different wavelength channels to transmit the resonant wavelength signal and the temperature signal respectively based on the same optical path.

[0112] In one possible implementation, the method further includes: pre-calibrating the temperature sensitivity coefficient and refractive index sensitivity coefficient of the optical fiber surface plasmon resonance sensing probe. Based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, a decoupling relationship between temperature and refractive index is constructed. Using the temperature signal, the wavelength shift component caused by temperature is separated and subtracted from the resonant wavelength signal to obtain the resonant wavelength shift caused only by the change in ion concentration at the negative electrode interface and lithium metal deposition.

[0113] In one possible implementation, the spectral characteristic parameters include the resonant wavelength shift, the minimum reflectance, and the full width at half maximum (FWHM); the spectral calculation module is further used for: Based on the reflection spectrum acquired and demodulated by the fiber optic signal demodulator, the reflection value at the point of lowest reflectance is determined as the minimum reflectance value. On either side of the point of lowest reflectivity, find the two wavelengths corresponding to the point where the reflectivity rises to half the sum of the minimum reflectivity and one. Define the interval between the two wavelengths as the full width at half maximum (FWHM).

[0114] In one possible implementation, the method also pre-stores a multi-level threshold mapping table calibrated based on the lithium plating evolution law; By comparing the spectral feature parameters with the multi-level threshold mapping table, it can be determined whether the current state is characterized by no lithium plating, initial deposition, dendrite formation, or short-circuit risk. The initial deposition state is determined by the resonance wavelength drift reaching a first warning threshold; the dendrite formation state is determined by the resonance wavelength drift reaching a second warning threshold, the resonance wavelength drift rate reaching a rate threshold, the minimum reflectance being lower than a first lower limit threshold, and the full width at half maximum (FWHM) of the reflection spectrum exceeding a preset broadening threshold; the short-circuit risk state is determined by the resonance wavelength drift reaching a third warning threshold, the minimum reflectance being lower than a second lower limit threshold, and the full WHM of the reflection spectrum exceeding a preset broadening threshold.

[0115] In one possible implementation, the method further includes: performing joint discrimination based on cell operating condition information, and configuring discrimination logic differently according to the charging stage. During the constant current charging phase, when the resonant wavelength drift rate exceeds the reference rate threshold under the corresponding charging rate, a warning signal for the initial deposition state is triggered. During the constant voltage charging stage, when the resonant wavelength drift increases in the opposite direction and the increase exceeds the preset fluctuation threshold during the natural decrease of current, a warning signal for the dendrite formation state or the short circuit risk state is triggered. During the resting phase, when the amount of resonant wavelength drift decreases less than the value at the end of constant voltage charging compared to the value at the end of constant voltage charging, a warning signal for the dendrite formation state or the short circuit risk state is triggered. The cell operating condition information includes at least one of voltage, current, temperature, state of charge, and number of cycles.

[0116] Please see Figure 4 , Figure 4 This is a flowchart illustrating a battery lithium plating and dendrite growth detection method according to another embodiment of this application. This embodiment mainly optimizes the problem of transitioning from single-cell early warning to battery pack safety control.

[0117] like Figure 4 As shown in the embodiments of this application, the battery lithium plating and dendrite growth detection method includes: S410. Insert the fiber surface plasmon resonance sensing probe into the cell and position it between the negative electrode plate and the separator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface.

[0118] S420: The internal temperature signal of the battery cell is obtained by using a stress-free fiber optic grating temperature sensor installed inside the battery cell.

[0119] S430: Receive the resonant wavelength signal and temperature signal, fuse the two signals to eliminate the wavelength drift component caused by temperature and extract spectral characteristic parameters.

[0120] S440. Based on the comparison results between the spectral characteristic parameters and the preset threshold, determine the stage of lithium plating and dendrite growth at the negative electrode interface, and output a warning signal of the corresponding level.

[0121] The descriptions of S410 to S440 can be referenced from those of S310 to S340, and the same technical effects can be achieved, so they will not be elaborated further.

[0122] S450. The warning signal is sent to the battery management system so that the battery management system performs a graded response to the warning signal.

[0123] Here, if microscopic lithium plating anomalies at the single-cell level are not addressed in time, they can easily evolve into thermal runaway at the battery pack level. By introducing actions from the battery management system, a closed loop from sensing to control can be achieved.

[0124] Specifically, the graded response steps may include: obtaining the grade of the warning signal; if the warning signal is in the initial deposition state, controlling the battery management system to record the event and alert relevant personnel; if the warning signal is in the dendrite formation state, controlling the battery management system to limit the charging rate or reduce the charging power; if the warning signal is in the short circuit risk state, controlling the battery management system to disconnect the high-voltage circuit and stop charging.

[0125] For example, the limiting charging rate can be set to be reduced to below 0.2C; the disconnection of the high-voltage circuit is specifically achieved by cutting off the high-voltage main relay.

[0126] In this way, by introducing a linkage mechanism of the battery management system, the microscopic abnormal signals of a single cell are transformed into macroscopic safety protection actions of the battery pack, effectively blocking the evolution path from local lithium plating to systemic thermal runaway, and improving the safety of the battery pack under high-risk operating conditions.

[0127] Based on the same concept, this application also provides a smart battery, including a battery cell, a packaging shell, and a battery lithium plating and dendrite growth detection system as described above; wherein, the battery cell includes a negative electrode sheet, a separator, and an electrolyte; and the packaging shell is used to encapsulate the battery cell.

[0128] In one possible implementation, the side wall of the packaging shell is provided with an optical fiber lead-out hole, and the optical fiber lead-out hole is double-sealed with hot melt adhesive and UV-curable adhesive to prevent electrolyte leakage and maintain the airtightness of the packaging; the pigtail of the optical fiber surface plasmon resonance sensing probe in the battery lithium plating and dendrite growth detection system extends through the optical fiber lead-out hole to the outside of the packaging shell for connection to an external optical fiber signal demodulator.

[0129] Here, in the cell stacking or winding process, the surface plasma resonance sensing probe of the optical fiber is positioned between the negative electrode and the separator, and the pigtail is fixed to the surface of the cell with electrolyte-resistant tape; after the aluminum-plastic film heat sealing is completed, hot melt adhesive is first injected through the optical fiber lead hole for preliminary sealing, and then UV curing adhesive is coated on the outer periphery of the hole and cured by light to form a double sealing structure.

[0130] This ensures the extraction of fiber optic signals while effectively resisting long-term corrosion from the electrolyte inside the battery cell, thus improving the sealing reliability and environmental adaptability of the smart battery throughout its entire life cycle.

[0131] In one possible implementation, the battery cell is a pouch cell with a single-cell capacity of 5Ah, and is fabricated using a lamination process; the end face of the optical fiber surface plasmon resonance sensing probe is 0.1mm-0.5mm away from the surface of the negative electrode sheet, and its axis is parallel to the surface of the negative electrode sheet.

[0132] Here, in the stacking process, the stacking clamping force is used to temporarily fix the plasma resonance sensing probe on the optical fiber surface, ensuring that the probe is located in the spatial region where lithium dendrites first form, so that the detection light field directly acts on the starting position of lithium deposition and dendrite growth.

[0133] This improves the sensitivity to detecting minute changes in the refractive index at the interface during the initial stage of lithium plating, enabling ultra-early warning.

[0134] Based on the same concept, embodiments of this application also provide a battery pack including a plurality of the aforementioned smart batteries.

[0135] In one possible implementation, the fiber optic surface plasmon resonance sensing probes in the plurality of smart batteries are connected in series on the same fiber optic bus via wavelength division multiplexing or time division multiplexing technology. The fiber optic bus is connected to a shared fiber optic signal demodulator to achieve distributed online monitoring of lithium plating at the battery pack level.

[0136] Here, the operating wavelength of the fiber surface plasmon resonance sensing probe in different smart batteries can be set in a preset range of around 1550nm, and the center wavelength of the stress-free fiber grating temperature sensor is set to around 1560nm; the fiber optic signal demodulator has a built-in wavelength division multiplexing unit, which separates the refractive index signal and the temperature signal according to the wavelength difference, thereby realizing the simultaneous transmission of two types of signals on a single fiber optic bus.

[0137] This significantly reduces the number of internal fiber optic cables in the battery pack, lowers wiring complexity, and reduces system costs by sharing a demodulator.

[0138] In one possible implementation, the battery pack further includes a battery management system, which is connected to a communication interface within each smart battery to receive graded warning signals and execute graded responses.

[0139] Here, when any smart battery outputs a warning signal indicating the initial deposition state, the battery management system records the event and pushes a prompt message to the vehicle's dashboard; when it outputs a warning signal indicating dendrite formation, the battery management system limits the charging rate to below 0.2C or reduces the discharge power; when it outputs a warning signal indicating a short circuit risk state, the battery management system controls the high-voltage main relay to disconnect, cuts off the high-voltage circuit, and stops charging to prevent thermal runaway from spreading within the battery pack.

[0140] In this way, the microscopic lithium plating anomaly signal at the single cell level can be transformed into an active safety protection action at the battery pack level, effectively blocking the evolution path from local lithium plating to systemic thermal runaway.

[0141] In this embodiment, the computer program, when run by the processor, can also execute other machine-readable instructions to perform other methods as described in the embodiments. For details on the specific execution steps and principles, please refer to the description of the embodiments, which will not be repeated here.

[0142] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0143] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0144] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0145] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0146] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0147] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A battery lithium plating and dendrite growth detection system, characterized in that, include: The fiber optic sensing module includes a fiber optic surface plasmon resonance sensing probe encapsulated in an electrolyte-resistant capillary. The fiber optic surface plasmon resonance sensing probe extends into the cell and is positioned between the negative electrode plate and the separator. The fiber optic surface plasmon resonance sensing probe is externally connected to a fiber optic signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface. The temperature compensation module includes a stress-free fiber optic temperature sensor installed inside the battery cell to acquire the internal temperature signal of the battery cell. The spectral calculation module is used to receive the resonance wavelength signal and the temperature signal, fuse the two signals to eliminate the wavelength drift component caused by temperature and extract spectral feature parameters; The graded early warning module is used to determine the stage of lithium plating and dendrite growth at the negative electrode interface based on the comparison results of the spectral characteristic parameters and preset thresholds, and output an early warning signal of the corresponding level.

2. The battery lithium plating and dendrite growth detection system according to claim 1, characterized in that, The fiber optic surface plasmon resonance sensing probe includes: Single-mode optical fiber, with the sensing end face treated by grinding and polishing; A gold film is deposited on the polished end face of a single-mode fiber to excite the surface plasmon resonance effect. An electrolyte-resistant capillary is sleeved around the periphery of the single-mode optical fiber, with the end face of the single-mode optical fiber located at the end face of the electrolyte-resistant capillary or extending outward therefrom, so that the gold film can contact the electrolyte. A sealing structure is provided to fill the gap between the electrolyte-resistant capillary and the single-mode optical fiber, as well as the junction between the end face of the electrolyte-resistant capillary and the single-mode optical fiber, for the purpose of blocking the electrolyte.

3. The battery lithium plating and dendrite growth detection system according to claim 1 or 2, characterized in that, The optical fiber surface plasmon resonance sensing probe and the stress-free fiber grating temperature sensor are connected in series on the same optical fiber bus and operate in different wavelength channels to transmit the resonance wavelength signal and the temperature signal respectively based on the same optical path.

4. The battery lithium plating and dendrite growth detection system according to claim 1, characterized in that, The spectral calculation module is specifically used for: The temperature sensitivity coefficient and refractive index sensitivity coefficient of the optical fiber surface plasmon resonance sensing probe were pre-calibrated. Based on the temperature sensitivity coefficient and the refractive index sensitivity coefficient, a decoupling relationship between temperature and refractive index is constructed. Using the temperature signal, the wavelength shift component caused by temperature is separated and subtracted from the resonant wavelength signal to obtain the resonant wavelength shift caused only by the change in ion concentration at the negative electrode interface and lithium metal deposition.

5. The battery lithium plating and dendrite growth detection system according to claim 4, characterized in that, The spectral characteristic parameters include resonance wavelength shift, minimum reflectance, and full width at half maximum (FWHM); the spectral calculation module is also used for: Based on the reflection spectrum acquired and demodulated by the fiber optic signal demodulator, the reflection value at the point of lowest reflectance is determined as the minimum reflectance value. On either side of the point of lowest reflectivity, find the two wavelengths corresponding to the point where the reflectivity rises to half the sum of the minimum reflectivity and one. Define the interval between the two wavelengths as the full width at half maximum (FWHM).

6. The battery lithium plating and dendrite growth detection system according to claim 1, characterized in that, The hierarchical early warning module has a multi-level threshold mapping table pre-stored based on the lithium plating evolution law; The graded early warning module determines whether the current state is characterized by no lithium plating, initial deposition, dendrite formation, or short circuit risk by comparing the spectral feature parameters with the multi-level threshold mapping table. The initial deposition state is determined by the resonance wavelength drift reaching a first warning threshold; the dendrite formation state is determined by the resonance wavelength drift reaching a second warning threshold, the resonance wavelength drift rate reaching a rate threshold, the minimum reflectance being lower than a first lower limit threshold, and the full width at half maximum (FWHM) of the reflection spectrum exceeding a preset broadening threshold; the short-circuit risk state is determined by the resonance wavelength drift reaching a third warning threshold, the minimum reflectance being lower than a second lower limit threshold, and the full WHM of the reflection spectrum exceeding a preset broadening threshold.

7. The battery lithium plating and dendrite growth detection system according to claim 6, characterized in that, The graded early warning module is also used to perform joint judgment based on the battery cell operating condition information, and to configure the judgment logic differently according to the charging stage: During the constant current charging phase, when the resonant wavelength drift rate exceeds the reference rate threshold under the corresponding charging rate, a warning signal for the initial deposition state is triggered. During the constant voltage charging stage, when the resonant wavelength drift increases in the opposite direction and the increase exceeds the preset fluctuation threshold during the natural decrease of current, a warning signal for the dendrite formation state or the short circuit risk state is triggered. During the resting phase, when the amount of resonant wavelength drift decreases less than the value at the end of constant voltage charging compared to the value at the end of constant voltage charging, a warning signal for the dendrite formation state or the short circuit risk state is triggered. The cell operating condition information includes at least one of voltage, current, temperature, state of charge, and number of cycles.

8. A method for detecting lithium plating and dendrite growth in batteries, characterized in that, Includes the following steps: An optical fiber surface plasmon resonance sensing probe is inserted into the cell and positioned between the negative electrode plate and the separator. The optical fiber surface plasmon resonance sensing probe is connected to an external optical fiber signal demodulator to obtain the surface plasmon resonance wavelength signal at the negative electrode interface. The internal temperature signal of the battery cell is obtained by using a stress-free fiber optic grating temperature sensor deployed inside the battery cell. The resonant wavelength signal and temperature signal are received, the two signals are fused to eliminate the wavelength drift component caused by temperature, and spectral characteristic parameters are extracted. Based on the comparison results between the spectral characteristic parameters and the preset threshold, the stage of lithium plating and dendrite growth at the negative electrode interface is determined, and a corresponding warning signal is output.

9. A smart battery, characterized in that, Includes battery cells, packaging housings, and a battery lithium plating and dendrite growth detection system according to any one of claims 1 to 7; in, Battery cell, including negative electrode plate, separator and electrolyte; A housing for encapsulating the battery cell.

10. A battery pack, characterized in that, Includes multiple smart batteries as described in claim 9.

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