Multi-parameter distributed optical fiber sensing system and method for monitoring battery arrays of energy storage systems

Abstract

A multi-parameter distributed optical fiber sensing system and method for monitoring a battery array of an energy storage system, which relates to the technical field of battery performance monitoring and is used to solve the problem that it is difficult to perform large-scale and multi-parameter monitoring on the performance of the battery array of the energy storage system in the prior art. The technical key points of the present invention include: the data acquisition subsystem includes a tunable light source and a multi-parameter signal acquisition module. The multi-parameter signal acquisition module is used to collect signal data such as the battery temperature, battery electrolyte density, and battery gas concentration of the battery array. It includes multiple groups of multi-parameter sensing units composed of a beam splitter coupler and a multi-parameter sensing probe. The multi-parameter sensing probe includes optical fiber sensors such as a fiber Bragg grating, a fiber Fabry-Perot cavity, and a gas absorption chamber; the data processing subsystem is used to demodulate the collected signals and obtain the values of the battery temperature, electrolyte density, and battery gas concentration in real time. The present invention can realize multi-parameter distributed sensing of the performance of the battery array of the energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of battery performance monitoring, and particularly relates to a multi-parameter distributed optical fiber sensing system and method for monitoring a battery array of an energy storage system. Background Art

[0002] With the development of the new energy industry, the number of energy storage systems is increasing, which has led to an increasing number of safety accidents such as fires and explosions in energy storage systems. An energy storage system includes a battery array composed of thousands of batteries. The current monitoring technology mainly conducts sampling temperature monitoring on the battery array of the energy storage system through electrical temperature sensors such as thermistors, and it is impossible to monitor each battery in the battery array, resulting in the inability to detect battery failures in a timely manner. In addition, the current monitoring technology often can only monitor the temperature and voltage of the battery array of the energy storage system, and cannot monitor deeper internal parameters of the battery, such as electrolyte density and gas concentration, etc., so it is difficult to measure the health status of the battery array. Generally speaking, the current monitoring technology is difficult to achieve large-scale and multi-parameter monitoring of the battery array of the energy storage system.

[0003] Electrical sensors often cannot do without metal materials and are easily eroded by the highly corrosive environment in the battery. In contrast, optical fiber sensors have the advantages of small size, corrosion resistance, electromagnetic interference resistance, etc., and can withstand the highly corrosive environment in the battery. Optical fiber sensors have various structures, such as fiber Bragg gratings, fiber Fabry-Perot cavities, tilted fiber gratings, fiber Michelson interferometers, fiber Mach-Zehnder interferometers, etc. These optical fiber sensor structures can achieve sensing of various different parameters. However, these optical fiber sensor structures often can only achieve single-point sensing and cannot achieve large-scale sensing. On the other hand, there are currently distributed optical fiber sensing technologies based on Rayleigh scattering, Brillouin scattering, and Raman scattering, but these distributed optical fiber sensing technologies can only achieve sensing of temperature and strain and cannot achieve multi-parameter sensing. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a multi-parameter distributed optical fiber sensing system and method for monitoring a battery array of an energy storage system to solve the problem that the prior art is difficult to perform large-scale and multi-parameter monitoring on the performance of the battery array of the energy storage system.

[0005] According to one aspect of the present invention, there is provided a multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system. The system includes a data acquisition subsystem and a data processing subsystem, and the output of the data acquisition subsystem is connected to the input of the data processing subsystem; wherein,

[0006] The data acquisition subsystem includes a tunable light source, a multi-parameter signal acquisition module, and a data acquisition card. The tunable light source is used to output laser light. The tunable light source is connected to the multi-parameter signal acquisition module. The multi-parameter signal acquisition module is used to collect a first signal including battery temperature, electrolyte density inside the battery, and battery gas concentration data in the battery array, and send the first signal to the data acquisition card;

[0007] The multi-parameter signal acquisition module consists of: a first fiber optic coupler, a fiber optic circulator, a second fiber optic coupler, a polarization beam splitter, a multi-parameter sensing unit group, a first photodetector, and a second photodetector; the input port of the first fiber optic coupler is connected to the tunable light source, and the output port is respectively connected to the input port of the second fiber optic coupler and the first port of the fiber optic circulator; the second port of the fiber optic circulator is connected to the multi-parameter sensing unit group, and the third port is connected to the input port of the second fiber optic coupler; the output port of the second fiber optic coupler is connected to the input port of the polarization beam splitter; the output ports of the polarization beam splitter are respectively connected to the input port of the first photodetector and the input port of the second photodetector; the output ports of the first photodetector and the second photodetector are both connected to the data acquisition channels of the data acquisition card.

[0008] Further, the multi-parameter sensing unit group includes multiple groups of sensing units connected in parallel, each consisting of a splitting coupler and a multi-parameter sensing probe; wherein, the output port of the splitting coupler of each group is respectively connected to the multi-parameter sensing probe of that group and the input port of the splitting coupler of the next group.

[0009] Further, the multi-parameter sensing probe consists of a fiber Bragg grating, a fiber Fabry - Perot cavity, and a gas absorption chamber; wherein, the fiber Fabry - Perot cavity is an empty cavity and is not closed.

[0010] Further, the included angle between the optical fiber main axis of the output port of the second fiber optic coupler and the optical fiber main axis of the input port of the polarization beam splitter is 45°.

[0011] Further, the data acquisition subsystem further includes a total fiber coupler and a light source instantaneous frequency signal acquisition module. The input port of the total fiber coupler is connected to the tunable light source, and the output port is connected to the light source instantaneous frequency signal acquisition module. The light source instantaneous frequency signal acquisition module is used to collect a second signal corresponding to the instantaneous frequency of the tunable light source. The light source instantaneous frequency signal acquisition module includes: an auxiliary fiber coupler, an auxiliary delay optical fiber, a first Faraday rotator, a second Faraday rotator, and a third photodetector. The input port of the auxiliary fiber coupler is connected to the total fiber coupler, the output port is respectively connected to one end of the auxiliary delay optical fiber and the second Faraday rotator, the reflection port is connected to the input port of the third photodetector, the other end of the auxiliary delay optical fiber is connected to the first Faraday rotator, and the output port of the third photodetector is connected to the data acquisition channel of the data acquisition card.

[0012] Further, the data acquisition subsystem further includes a gas reference spectral signal acquisition module. The gas reference spectral signal acquisition module is used to collect a third signal after the laser emitted by the tunable light source is absorbed by gas molecules. The gas reference spectral signal acquisition module includes a gas cell and a fourth photodetector. The gas cell is respectively connected to the output port of the total fiber coupler and the input port of the fourth photodetector, and the output port of the fourth photodetector is connected to the data acquisition channel of the data acquisition card.

[0013] Further, the data processing subsystem includes a storage module, a light source phase noise compensation module, a light source wavelength correction module, a multi-parameter spectral demodulation module, a temperature value acquisition module, an electrolyte density value acquisition module, and a gas concentration value acquisition module. Among them,

[0014] The storage module is used to store the first performance change relationship between the pre-calibrated battery temperature and its corresponding spectral center wavelength, the second performance change relationship between the battery electrolyte density and its corresponding spectral center wavelength, the third performance change relationship between the battery gas concentration and its corresponding spectral absorption intensity, and the standard gas absorption spectrum.

[0015] The light source phase noise compensation module is used to perform noise compensation on the first signal and the third signal by using the collected second signal. The specific process includes: preprocessing the collected second signal to obtain the instantaneous phase of the second signal, and using the instantaneous phase to resample the first signal and the third signal to obtain the first resampled signal and the third resampled signal corresponding to the phase noise compensation.

[0016] The light source wavelength correction module is used to correct the first resampled signal by using the standard gas absorption spectrum and the third resampled signal. The specific process includes: First, identify the central wavelengths of two absorption peaks in the third resampled signal according to the central wavelengths of two absorption peaks in the standard gas absorption spectrum. Then, calculate the scaling factor and the translation factor according to the central wavelengths. The calculation expressions of the scaling factor α and the translation factor β are as follows:

[0017]

[0018]

[0019] In the formula, λ1 and λ2 represent the central wavelengths of two absorption peaks in the standard gas absorption spectrum; λ1′ and λ2′ represent the central wavelengths of two absorption peaks in the third resampled signal. Finally, correct the first resampled signal according to the scaling factor α and the translation factor β.

[0020] The multi-parameter spectrum demodulation module is used to demodulate the corrected first resampled signal to obtain the first central wavelength in the spectral data corresponding to the fiber Bragg grating in each multi-parameter sensing probe, the second central wavelength in the spectral data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

[0021] The battery temperature value acquisition module is used to calculate and obtain the battery temperature value according to the first performance change relationship and the first central wavelength.

[0022] The electrolyte density value acquisition module is used to calculate and obtain the electrolyte density value according to the second performance change relationship, the second central wavelength, and the battery temperature value.

[0023] The gas concentration value acquisition module is used to calculate and obtain the battery gas concentration value according to the third performance change relationship and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

[0024] Further, the process of demodulating the corrected first resampled signal in the multi-parameter spectrum demodulation module includes: First, perform a fast Fourier transform on the corrected first resampled signal to obtain the reflection peaks corresponding to the fiber Bragg grating, the fiber Fabry-Perot cavity, and the gas absorption chamber connected in each multi-parameter sensing probe. Then, select the reflection peaks corresponding to each fiber Bragg grating, the fiber Fabry-Perot cavity, and the gas absorption chamber to perform an inverse Fourier transform to obtain the spectral data corresponding to each fiber Bragg grating, the fiber Fabry-Perot cavity, and the gas absorption chamber, so as to obtain the first central wavelength, the second central wavelength, and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

[0025] Further, the system further includes a display and alarm subsystem, which is configured to display in real time the temperature value of the battery array, the electrolyte density value, and the gas concentration value, and set a temperature threshold, an electrolyte density threshold, and a gas concentration threshold to give an alarm when the temperature value exceeds the temperature threshold, the electrolyte density value exceeds the electrolyte density threshold, or the gas concentration value exceeds the gas concentration threshold.

[0026] According to another aspect of the present invention, there is provided a multi-parameter distributed optical fiber sensing method for monitoring a battery array of an energy storage system, the method comprising the following steps:

[0027] Step 1: Immerse the probes of multiple groups of multi-parameter sensing probes into the electrolyte of the battery array; the multi-parameter sensing probes include fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers; wherein, the fiber Fabry-Perot cavity is a cavity and is not closed;

[0028] Step 2: Collect a first signal including data on the battery temperature, the electrolyte density inside the battery, and the battery gas concentration in the battery array, a second signal corresponding to the instantaneous frequency of the tunable light source, and a third signal after the laser emitted by the tunable light source is absorbed by gas molecules;

[0029] Step 3: Use the second signal to perform noise compensation on the first signal and the third signal to obtain a first resampled signal and a third resampled signal after noise compensation;

[0030] Step 4: Use the standard gas absorption spectrum and the third resampled signal to correct the first resampled signal to obtain a corrected first resampled signal;

[0031] Step 5: Perform demodulation processing on the corrected first resampled signal to obtain a first central wavelength in the spectral data corresponding to the fiber Bragg grating in each group of multi-parameter sensing probes, a second central wavelength in the spectral data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber;

[0032] Step 6: Calculate and obtain the battery temperature value according to the first central wavelength and a pre-calibrated first performance change relationship; calculate and obtain the electrolyte density value according to the second central wavelength, the battery temperature value, and a pre-calibrated second performance change relationship; calculate and obtain the battery gas concentration value according to the absorption intensity of the spectrum corresponding to the gas absorption chamber and a pre-calibrated third performance change relationship.

[0033] The beneficial technical effects of the present invention are:

[0034] The present invention provides a multi-parameter distributed optical fiber sensing system and method for monitoring a battery array of an energy storage system, which can realize large-scale and multi-parameter monitoring of the performance of the battery array of the energy storage system. The system of the present invention multiplexes a large number of point-type optical fiber sensors, including but not limited to fiber Bragg gratings, fiber Fabry-Perot cavities, gas absorption cells, tilted fiber Bragg gratings, etc. A variety of point-type optical fiber sensors can be connected in series or in parallel to form a multi-parameter sensing probe unit to realize multi-parameter monitoring of the battery array of the energy storage system; multiple identical multi-parameter sensing probe units are connected in parallel to form a large-scale monitoring network to further realize large-scale multi-parameter monitoring of the battery array of the energy storage system; it can ensure that there is no signal crosstalk between each multi-parameter sensing probe unit, and it can also ensure that there is no signal crosstalk between each point-type optical fiber sensor that composes the multi-parameter sensing probe unit. Further, a light source phase noise compensation module can compensate for the non-linear frequency sweep error generated by the tunable light source during the wavelength scanning process, and a light source wavelength correction module can correct the wavelength drift error generated by the tunable light source due to environmental factor changes. The present invention can realize distributed multi-parameter sensing for the battery array of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention can be better understood by referring to the following description in conjunction with the accompanying drawings. The accompanying drawings, together with the following detailed description, are included in this specification and form a part of this specification, and are used to further illustrate the preferred embodiments of the present invention and explain the principles and advantages of the present invention.

[0036] Figure 1 It is a schematic structural diagram of a multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system provided by an embodiment of the present invention;

[0037] Figure 2 It is another schematic structural diagram of a multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system provided by an embodiment of the present invention;

[0038] Figure 3 It is a schematic diagram of the connection manner of multiple multi-parameter sensing probes in an embodiment of the present invention; wherein, (a) is the series connection manner; (b) is the parallel connection manner;

[0039] Figure 4 It is a schematic flowchart of a multi-parameter distributed optical fiber sensing method for monitoring a battery array of an energy storage system provided by an embodiment of the present invention;

[0040] Figure 5Schematic diagram of the principle for multiplexing and demodulating signals collected by a multi-parameter sensing probe in an embodiment of the present invention; wherein, (a) shows the relationship between the frequency and time when the reference light and the reflected lights corresponding to the fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber in a multi-parameter sensing probe reach a photodetector; (b) shows the reflection peaks corresponding to the fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber in a multi-parameter sensing probe; (c) shows the reflection spectra corresponding to the fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber in a multi-parameter sensing probe.

[0041] Figure 6 Example diagram of the spatial position distribution of probes obtained by demultiplexing 20 multi-parameter sensing probes in an embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the response relationships of a fiber Bragg grating, a fiber Fabry-Perot cavity, and a gas absorption chamber to temperature, electrolyte density, and gas concentration in an embodiment of the present invention; wherein, (a) is the linear fitting relationship between the central wavelength of the fiber Bragg grating and the battery temperature; (b) is the linear fitting relationship between the central wavelength of the fiber Fabry-Perot cavity and the battery electrolyte density; (c) is the linear fitting relationship between the central wavelength of the fiber Fabry-Perot cavity and the battery temperature; (d) is the linear fitting relationship between the absorption intensity of the gas absorption chamber and the battery gas concentration. Detailed implementation manners

[0043] To enable those skilled in the art to better understand the solution of the present invention, the exemplary embodiments or examples of the present invention will be described below in conjunction with the accompanying drawings. Based on the embodiments or examples in the present invention, all other embodiments or examples obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0044] To solve the problem that it is difficult to achieve large-scale and multi-parameter sensing in the existing battery array monitoring technology for energy storage systems, the present invention provides a multi-parameter distributed optical fiber sensing system and method for monitoring a battery array of an energy storage system. The present invention uses multiple groups of multi-parameter sensing probe units to achieve multi-parameter distributed monitoring of the battery array of the energy storage system. Among them, each multi-parameter sensing probe is composed of point-type optical fiber sensors such as a fiber Bragg grating, a fiber Fabry-Perot cavity, and a gas absorption chamber, which are respectively used to monitor the temperature of the battery array, the electrolyte concentration of the battery array, and the gas concentration inside the battery array, so as to realize the health status monitoring of the battery array of the energy storage system.

[0045] An embodiment of the present invention provides a multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system, as Figure 1 、 2As shown, the system includes a data acquisition subsystem 1 and a data processing subsystem 2. The output of the data acquisition subsystem 1 is connected to the input of the data processing subsystem 2. Among them, the data acquisition subsystem 1 includes a tunable light source 11, a multi-parameter signal acquisition module 12, and a data acquisition card 13. The tunable light source 11 is used to output laser light. The tunable light source 11 is connected to the multi-parameter signal acquisition module 12. The multi-parameter signal acquisition module 12 is used to acquire a first signal including battery temperature, electrolyte density inside the battery, and battery gas concentration data in the battery array, and send the first signal to the data acquisition card 13;

[0046] The multi-parameter signal acquisition module 12 consists of: a first fiber optic coupler 121, a fiber optic circulator 123, a second fiber optic coupler 124, a polarization beam splitter 122, a multi-parameter sensing unit group 125, a first photodetector 126, and a second photodetector 127. The input port of the first fiber optic coupler 124 is connected to the tunable light source 11, and the output ports are respectively connected to the input port of the second fiber optic coupler 124 and the first port of the fiber optic circulator 123. The second port of the fiber optic circulator 123 is connected to the multi-parameter sensing unit group 125, and the third port is connected to the input port of the second fiber optic coupler 124. The output port of the second fiber optic coupler 124 is connected to the input port of the polarization beam splitter 122. The output ports of the polarization beam splitter 122 are respectively connected to the input ports of the first photodetector 126 and the second photodetector 127. The output ports of the first photodetector 126 and the second photodetector 127 are both connected to the data acquisition channels of the data acquisition card 13. Among them, the included angle between the optical fiber main axis of the output port of the second fiber optic coupler 124 and the optical fiber main axis of the input port of the polarization beam splitter 122 is 45°.

[0047] In this embodiment, optionally, the multi-parameter sensing unit group 125 includes multiple groups of sensing units connected in parallel, each consisting of a beam splitting coupler and a multi-parameter sensing probe. Among them, the output ports of the beam splitting coupler of each group are respectively connected to the multi-parameter sensing probe of this group and the input port of the beam splitting coupler of the next group.

[0048] In this embodiment, optionally, the multi-parameter sensing probe consists of, but is not limited to, a fiber Bragg grating, a fiber Fabry-Perot cavity, and a gas absorption chamber. Among them, the fiber Fabry-Perot cavity is a cavity and is not closed. Fiber optic sensor devices such as fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers can be connected in series, as shown in Figure 3 (a), or can be connected in parallel, as shown in Figure 3 (b).

[0049] In this embodiment, optionally, the data acquisition subsystem 1 further includes a total fiber coupler 14 and a light source instantaneous frequency signal acquisition module 15. The input port of the total fiber coupler 14 is connected to the tunable light source 11, and the output port is connected to the light source instantaneous frequency signal acquisition module 15. The light source instantaneous frequency signal acquisition module 15 is used to collect a second signal corresponding to the instantaneous frequency of the tunable light source. The light source instantaneous frequency signal acquisition module 15 includes: an auxiliary fiber coupler 151, an auxiliary delay optical fiber 152, a first Faraday rotator 153, a second Faraday rotator 154, and a third photodetector 155. The input port of the auxiliary fiber coupler 151 is connected to the total fiber coupler 14, and the output port is respectively connected to one end of the auxiliary delay optical fiber 152 and the second Faraday rotator 154. The reflection port is connected to the input port of the third photodetector 155. The other end of the auxiliary delay optical fiber 152 is connected to the first Faraday rotator 153. The output port of the third photodetector 155 is connected to the data acquisition channel of the data acquisition card 13.

[0050] In this embodiment, optionally, the data acquisition subsystem 1 further includes a gas reference spectrum signal acquisition module 16. The gas reference spectrum signal acquisition module 16 is used to collect a third signal after the laser emitted by the tunable light source is absorbed by gas molecules. The gas reference spectrum signal acquisition module 16 includes a gas cell 161 and a fourth photodetector 162. The gas cell 161 is respectively connected to the output port of the total fiber coupler 14 and the input port of the fourth photodetector 162. The output port of the fourth photodetector 162 is connected to the data acquisition channel of the data acquisition card 13.

[0051] In this embodiment, optionally, the data processing subsystem 2 includes a storage module 21, a light source phase noise compensation module 22, a light source wavelength correction module 23, a multi-parameter spectrum demodulation module 24, a temperature value acquisition module 25, an electrolyte density value acquisition module 26, and a gas concentration value acquisition module 27. Among them, the storage module 21 is used to store the first performance change relationship between the pre-calibrated battery temperature and its corresponding spectral center wavelength, the second performance change relationship between the battery electrolyte density and its corresponding spectral center wavelength, the third performance change relationship between the battery gas concentration and its corresponding spectral absorption intensity, and the standard gas absorption spectrum.

[0052] The light source phase noise compensation module 22 is used to perform noise compensation on the first signal and the third signal by using the collected second signal to compensate for the non-linear frequency sweep error caused by the tunable light source 11 during the wavelength scanning process. The specific process includes: preprocessing the collected second signal to obtain the instantaneous phase of the second signal, and using the instantaneous phase to resample the first signal and the third signal to obtain the first resampled signal and the third resampled signal corresponding to the phase noise compensation.

[0053] The light source wavelength correction module 23 is used to correct the first resampled signal by using the standard gas absorption spectrum and the third resampled signal, so as to correct the wavelength drift error generated by the tunable light source 11 due to environmental factor changes; the specific process includes: First, identify the central wavelengths of the two absorption peaks in the third resampled signal according to the central wavelengths of the two absorption peaks in the standard gas absorption spectrum; then, calculate and obtain the scaling factor and the translation factor according to the central wavelengths; among them, the calculation expressions of the scaling factor α and the translation factor β are:

[0054]

[0055]

[0056] In the formula, λ1 and λ2 represent the central wavelengths of the two absorption peaks in the standard gas absorption spectrum; λ1′ and λ2′ represent the central wavelengths of the two absorption peaks in the third resampled signal; finally, correct the horizontal axis of the first resampled signal according to the scaling factor α and the translation factor β;

[0057] The multi-parameter spectrum demodulation module 24 is used to demodulate the corrected first resampled signal to obtain the first central wavelength in the spectrum data corresponding to the fiber Bragg grating in each multi-parameter sensing probe, the second central wavelength in the spectrum data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber;

[0058] The temperature value acquisition module 25 is used to calculate and obtain the battery temperature value according to the first performance change relationship and the first central wavelength; the electrolyte density value acquisition module 26 is used to calculate and obtain the electrolyte density value according to the second performance change relationship, the second central wavelength and the battery temperature value; the gas concentration value acquisition module 27 is used to calculate and obtain the battery gas concentration value according to the third performance change relationship and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

[0059] In this embodiment, optionally, the process of demodulating the corrected first resampled signal in the multi-parameter spectrum demodulation module 24 includes: First, perform a fast Fourier transform on the corrected first resampled signal to obtain the reflection peaks corresponding to the fiber Bragg grating, the fiber Fabry-Perot cavity, and the gas absorption chamber connected in each multi-parameter sensing probe; then, select the reflection peaks corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber for inverse Fourier transform to obtain the spectrum data corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber, so as to obtain the first central wavelength, the second central wavelength, and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

[0060] In this embodiment, optionally, the system further includes a display and alarm subsystem 3. The display and alarm subsystem 3 is configured to display in real time the temperature value of the battery array, the electrolyte density value, and the gas concentration value, and set a temperature threshold, an electrolyte density threshold, and a gas concentration threshold to trigger an alarm when the temperature value exceeds the temperature threshold, the electrolyte density value exceeds the electrolyte density threshold, or the gas concentration value exceeds the gas concentration threshold.

[0061] Another embodiment of the present invention provides a multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system, as Figure 2 shown. The system includes: a tunable light source 11, a data acquisition card 13, a main optical fiber coupler 14, an auxiliary optical fiber coupler 151, an auxiliary delay optical fiber 152, a first Faraday rotator mirror 153, a second Faraday rotator mirror 154, a gas cell 161, a first optical fiber coupler 121, an optical fiber circulator 123, a second optical fiber coupler 124, a polarization beam splitter 122, a first multi-parameter optical fiber coupler 1251, a second multi-parameter optical fiber coupler 1252, a third multi-parameter optical fiber coupler 1253, a first multi-parameter sensing probe 1254, a second multi-parameter sensing probe 1255, a third multi-parameter sensing probe 1256, a first photodetector 126, a second photodetector 127, a third photodetector 155, and a fourth photodetector 162.

[0062] The laser output of the tunable light source 11 is connected to the total fiber coupler 14. The first port of the total fiber coupler 14 is connected to the auxiliary fiber coupler 151, the second port is connected to the gas cell 161, and the third port is connected to the first fiber coupler 121. The first port of the auxiliary fiber coupler 151 is connected to the auxiliary delay optical fiber 152, and the second port is connected to the second Faraday rotator 154. The auxiliary delay optical fiber 152 is connected to the first Faraday rotator 153. The reflection port of the auxiliary fiber coupler 151 is connected to the third photodetector 155, and the third photodetector 155 is connected to the data acquisition channel of the data acquisition card 13; the gas cell 161 is connected to the fourth photodetector 162, and the fourth photodetector 162 is connected to the data acquisition channel of the data acquisition card 13; the first port of the first fiber coupler 121 is connected to the second fiber coupler 124, and the second port is connected to the first port of the fiber circulator 123. The second port of the fiber circulator 123 is connected to the first optical coupler 1251, and the third port is connected to the second fiber coupler 124. The first port of the first optical coupler 1251 is connected to the first multi-parameter sensing probe 1254, and the second port is connected to the second optical coupler 1252. The first port of the second optical coupler 1252 is connected to the second multi-parameter sensing probe 1255, and the second port is connected to the third optical coupler 1253. The first port of the third optical coupler 1253 is connected to the third multi-parameter sensing probe 1256, and the second port is idle or used for connecting a series of subsequent multi-parameter sensing probes. The second fiber coupler 124 is connected to the polarization beam splitter 122, and the polarization beam splitter 122 is connected to the first photodetector 126 and the second photodetector 127. The first photodetector 126 and the second photodetector 127 are connected to the data acquisition channel of the data acquisition card 13.

[0063] In this embodiment, optionally, the central wavelength of the tunable light source 11 is 1550 nm, and the non-hop mode wavelength tuning range is greater than 60 nm. The linearly swept laser beam output by the tunable light source 11 is divided into three paths by the total fiber coupler 14. One path is used to assist in correcting the nonlinear error of the light source sweep frequency, one path is used to correct the wavelength drift error of the light source, and one path is used to multiplex a series of fiber multi-parameter sensing probes to realize multi-parameter distributed battery array monitoring; the output light of the tunable light source 11 is divided into three parts. Among them, the first port accounts for 1%, the second port accounts for 1%, and the third port accounts for 98%; the coupling ratio of the auxiliary fiber coupler 151 is 50:50; the coupling ratio of the second fiber coupler 124 is 50:50; the coupling ratio of the first fiber coupler 121 is 99:1, where the first port accounts for 1% and the second port accounts for 99%.

[0064] In this embodiment, optionally, the first fiber coupler 121, the fiber circulator 123, the second fiber coupler 124, and the polarization beam splitter 122 are all polarization-maintaining fiber devices.

[0065] In this embodiment, optionally, the splitting ratios of optical splitter 1251, optical splitter 1252, and optical splitter 1253 are all 99:1, where the first port accounts for 1% and the second port accounts for 99%.

[0066] In this embodiment, optionally, the gas filled in the gas cell can be hydrogen cyanide or acetylene, and the filled gas is selected according to the wavelength range of the tunable light source 11. The selection principle is that the gas has at least two absorption peaks between the wavelengths of 1520 nm and 1580 nm.

[0067] In this embodiment, optionally, the bandwidths of the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector are 80 MHz.

[0068] In this embodiment, optionally, the first multi-parameter sensing probe, the second multi-parameter sensing probe, and the third multi-parameter sensing probe are all composed of an optical fiber Bragg grating, an optical fiber Fabry-Perot cavity, and a gas absorption chamber. Among them, the spectral center wavelength of the optical fiber Bragg grating is about 1550 nm; the cavity length of the optical fiber Fabry-Perot cavity is about 100 μm, and the cavity is not closed, and the external liquid can enter the cavity; the gas absorption chamber is open, allowing the surrounding gas to enter the absorption chamber. The optical fiber Bragg grating is used to monitor the temperature of the battery, the optical fiber Fabry-Perot cavity is used to monitor the density of the battery electrolyte, and the gas absorption chamber is used to monitor the gas concentration of the battery.

[0069] The fiber Bragg grating (FBG) sensor is a type of grating optical sensor with a periodic refractive index modulation structure in the fiber core. The change in ambient temperature will cause changes in the grating period and the effective refractive index of the grating, resulting in a change in the spectral center wavelength of the fiber Bragg grating. Therefore, it can be used for battery temperature monitoring.

[0070] The fiber Fabry-Perot (FP) sensor is a type of interferometric optical sensor composed of two parallel reflective end faces in the optical fiber. The cavity sandwiched between the two end faces can accommodate the external liquid, and the change in the liquid refraction will cause a change in the optical path difference between the two end faces, resulting in a change in the spectral center wavelength of the fiber Fabry-Perot cavity. Therefore, it can be used for refractive index sensing. Since there is a linear correlation between the density and refractive index of the battery electrolyte, the fiber Fabry-Perot cavity can also be used for monitoring the density of the battery electrolyte.

[0071] The gas absorption cell (GC) consists of two fiber collimators and a cavity. The cavity is sandwiched between two facing fiber collimators. The ambient gas is dispersed in the cavity. The laser beam irradiates the gas in the cavity through one fiber collimator and is then received by the other fiber collimator. For a specific gas, a gas absorption peak will be generated at a specific wavelength, and the intensity of the absorption peak is proportional to the gas concentration. Therefore, it can be used for battery gas concentration sensing.

[0072] In this embodiment, optionally, a series of sensor arrays equivalent to the sensor array composed of the third optical splitter coupler 1253 and the third multi-parameter sensing probe 1256 can be connected after the second port of the third optical splitter coupler 1253, and an optical amplifier can be connected as a relay after the optical power decays to a certain extent to achieve the multiplexing of an infinite number of sensor arrays.

[0073] Another embodiment of the present invention provides a multi-parameter distributed optical fiber sensing method for monitoring a battery array of an energy storage system, as Figure 4 shown. The method includes the following steps:

[0074] Step 1: Immerse the probes of multiple groups of multi-parameter sensing probes into the electrolyte of the battery array; the multi-parameter sensing probes include fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption cells; among them, the fiber Fabry-Perot cavity is a cavity and is not closed;

[0075] Step 2: Use the multi-parameter distributed optical fiber sensing system in the above embodiment to collect a first signal (i.e., the multi-parameter sensing signal in the figure) including the battery temperature, the density of the electrolyte in the battery, and the battery gas concentration data in the battery array, a second signal corresponding to the instantaneous frequency of the tunable light source (i.e., the light source instantaneous frequency in the figure), and a third signal after the laser emitted by the tunable light source is absorbed by gas molecules (i.e., the gas reference spectrum in the figure); among them, for the collection process of the first signal: the laser beam is divided into two paths by the first fiber coupler. The laser output from the first port enters the second fiber coupler as the reference light, and the laser output from the second port enters the first optical splitter coupler through the fiber optic circulator as the signal light and enters the first multi-parameter sensing probe from the first port of the first optical splitter coupler. The reflected light passes through the fiber optic circulator again along the original path and enters the second fiber coupler and is mixed with the reference light; similarly, the reflected lights from the second multi-parameter sensing probe, the third multi-parameter sensing probe, and a series of subsequent sensor arrays all pass through the fiber optic circulator and enter the second fiber coupler and are mixed with the reference light. The generated mixed signal is detected by a photodetector after passing through a polarization beam splitter and is collected by a data acquisition card for subsequent processing;

[0076] Step 3: Use the second signal to perform noise compensation on the first signal and the third signal, and obtain the first resampled signal after noise compensation (i.e., the multi-parameter sensing signal after non-linear compensation in the figure) and the third resampled signal (i.e., the gas reference spectrum after non-linear compensation in the figure);

[0077] Step 4: Use the standard gas absorption spectrum and the third resampled signal to correct the first resampled signal, and obtain the first resampled signal after correction (i.e., the multi-parameter sensing signal after wavelength correction in the figure);

[0078] Step 5: Perform demodulation processing on the first resampled signal after correction, and obtain the first central wavelength in the spectral data corresponding to the fiber Bragg grating in each group of multi-parameter sensing probes, the second central wavelength in the spectral data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber;

[0079] Step 6: Calculate and obtain the battery temperature value according to the first central wavelength and the pre-calibrated first performance change relationship; calculate and obtain the electrolyte density value according to the second central wavelength, the battery temperature value and the pre-calibrated second performance change relationship; calculate and obtain the battery gas concentration value according to the absorption intensity of the spectrum corresponding to the gas absorption chamber and the pre-calibrated third performance change relationship.

[0080] In this embodiment, optionally, Step 3 is to compensate for the non-linear frequency sweep error caused by the tunable light source during the wavelength scanning process. The specific compensation process includes: First, read the second signal I1(t) collected by the light source instantaneous frequency acquisition module, and perform preprocessing on the second signal I1(t), that is: obtain the real part and the imaginary part of the second signal through Hilbert transform, and perform arctangent operation on the real part and the imaginary part to obtain the instantaneous phase Φ1(t) of the second signal, which is proportional to the instantaneous frequency of the light source; Then, read the third signal I2(t) collected by the gas reference spectrum acquisition module, and resample the third signal I2(t) at equal phase intervals with the instantaneous phase Φ1(t) to obtain the third resampled signal I2’(t) after phase noise compensation; Read the first signal I3(t) collected by the multi-parameter signal acquisition module, and resample the first signal I3(t) at equal phase intervals with the instantaneous phase Φ1(t) to obtain the first resampled signal I3’(t) after phase noise compensation.

[0081] In this embodiment, optionally, step four is to correct the wavelength drift error caused by environmental factor changes of the tunable light source. The specific process of the correction includes: First, read the standard gas absorption spectrum I0 in the storage module, and read the third resampled signal I2’(t); identify the central wavelengths λ1 and λ2 of the two absorption peaks in the standard gas absorption spectrum I0, and identify the central wavelengths λ1’ and λ2’ of the two absorption peaks in the third resampled signal I2’(t); according to the central wavelengths λ1 and λ2, and the central wavelengths λ1’ and λ2’, obtain the scaling factor α and the translation factor β. The expression of the scaling factor α is α = (λ1 - λ2) / (λ1’ - λ2’), and the expression of the translation factor β is β = (λ1’*λ2 - λ2’*λ1) / (λ1’ - λ2’); read the first resampled signal I3’(t), obtain the horizontal axis X of the first resampled signal I3’(t), and correct the first resampled signal I3’(t) according to the scaling factor α and the translation factor β to obtain the corrected horizontal axis X’, and the expression of the horizontal axis X’ is X’ = α*X + β; replace the original horizontal axis X with the horizontal axis X’ to obtain the corrected first resampled signal, that is, the wavelength correction signal I3”(t).

[0082] In this embodiment, optionally, the principle for demodulation in step five is as follows: The change of the electric field of the reference light with time when it reaches the photodetector can be expressed as: E R (t) = E R0 exp{jφ(t)}, where E R0 represents the initial amplitude of the reference light electric field, and φ(t) represents the change of the phase of the reference light with time; the change of the electric field of the partial reflected light of the signal light with time when it reaches the photodetector can be expressed as: E P (t - τ) = E P0 exp{jφ(t - τ)}, where E P0 represents the initial amplitude of the signal light electric field, and φ(t - τ) represents the change of the phase of the signal light with time. Due to there being many reflection points, the reflected light generated by these reflection points coherently superposes with the reference light to form the final mixed-frequency signal, and its intensity can be expressed as:

[0083]

[0084] In the formula, E Pm represents the initial amplitude of the electric field of the m-th reflection point, r m represents the electric field amplitude reflectivity of the m-th reflection point, and τ m represents the time delay of the m-th reflection point relative to the reference light.

[0085] It can be seen that the final mixed-frequency signal contains the reflectivity r m related to the time delay τ mInformation. By appropriately processing the data, the spectral signal corresponding to a certain time delay can be demodulated, and the time delay corresponds to the position of the sensing unit. Therefore, the spectral data of multiple sensing units are obtained.

[0086] The specific process of demodulation processing includes: performing a fast Fourier transform on the wavelength correction signal I3”(t) to obtain the reflection peaks corresponding to the fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers connected in each multi-parameter sensing probe; then, selecting the reflection peaks corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber for inverse Fourier transform to obtain the spectral data corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber, as well as the central wavelengths corresponding to the three spectral data.

[0087] Taking an example further, the specific formation process of the mixed-frequency signal and the demodulation process of the spectral signal are as Figure 5 shown. The relationship between the frequency and time of the reference light after reaching the photodetector is as Figure 5 (shown by the solid line in (a)) (LO). Since the positions of each multi-parameter sensing probe and the fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers that make up the multi-parameter sensing probe in the optical fiber link are different, the corresponding reflected lights have different time delays after reaching the photodetector, as Figure 5 (shown in (a)). The reflected light of the fiber Bragg grating in the first multi-parameter sensing probe is denoted as S11, the reflected light of the fiber Fabry-Perot cavity is denoted as S12, and the reflected light of the gas absorption chamber is denoted as S13; similarly, the reflected lights of the fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber in the second multi-parameter sensing probe can be denoted as S21, S22, and S23, and so on. These reflected lights interfere with the reference light to generate beat frequency signals with frequencies f 11 、f 12 and f 13 respectively. These beat frequency signals are superimposed to form an aliased signal that is detected by the photodetector and collected by the data acquisition card.

[0088] Then, performing a fast Fourier transform (FFT) on the mixed-frequency signal can obtain the reflection peaks (S11), (S12), and (S13) corresponding to the fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber in the first multi-parameter sensing probe, as Figure 5 (shown in (b)). Similarly, the reflection peaks corresponding to the fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers in the second and subsequent multi-parameter sensing probes can also be obtained, as Figure 6 shown.

[0089] Use window functions to separately select three reflection peaks and perform inverse Fourier transform (IFFT) to obtain the spectra of the fiber Bragg grating (S11 spectrum), the fiber Fabry-Perot cavity (S12 spectrum), and the gas absorption chamber (S13 spectrum) in the first multi-parameter sensing probe, as shown in Figure 5 (c). Similarly, continue to connect a series of sensing units composed of optical splitters and multi-parameter sensing probes after the second port of the first optical splitter, and thus multiplexing of a series of multi-parameter sensing probes can be achieved, and demodulation of each sensing unit can be realized according to the above steps.

[0090] In this embodiment, optionally, for obtaining the battery temperature value in step six, first, the first performance change relationship between the battery temperature and its corresponding spectral center wavelength needs to be pre-calibrated: obtain the spectral center wavelengths corresponding to a series of signals at known battery temperatures collected by the fiber Bragg grating sensor, and obtain the linear fitting function y1 = a1*T + b1, where y1 is the spectral center wavelength, T is the temperature, and a1 and b1 are fitting coefficients, as shown in Figure 7 (a); according to the above linear fitting function, the first performance change relationship can be obtained as: T’ = (y1’ - b1) / a1, where y1’ is the spectral center wavelength corresponding to the fiber Bragg grating in actual measurement, and T’ is the temperature value to be measured; then, when the battery temperature changes, since its corresponding spectral center wavelength also shifts, the battery temperature value in the battery array can be calculated according to the pre-calibrated first performance change relationship.

[0091] For obtaining the battery electrolyte density value, first, the second performance change relationship between the electrolyte density and its corresponding spectral center wavelength needs to be pre-calibrated: obtain the spectral center wavelengths corresponding to a series of signals at known battery electrolyte densities collected by the fiber Fabry-Perot cavity sensor, and obtain the linear fitting function y2 = a2*ρ + b2, where y2 is the spectral center wavelength, ρ is the electrolyte density, and a2 and b2 are fitting coefficients, as shown in Figure 7 (b); obtain the spectral center wavelengths corresponding to a series of signals at known battery temperatures collected by the fiber Fabry-Perot cavity sensor, and obtain the linear fitting function y3 = a3*T + b3, where y3 is the spectral center wavelength, T is the temperature, and a3 and b3 are fitting coefficients, as shown in Figure 7(c); according to the above two linear fitting functions, the second performance change relationship can be obtained as: ρ’ = (y2’ - a3 * T’ - b2) / a2 + (a3 * b3) / (a1 * a2), where y2’ is the central wavelength of the spectrum corresponding to the fiber Fabry - Perot cavity obtained in the actual measurement, T’ is the temperature value to be measured obtained in the previous step, and ρ’ is the electrolyte density value to be measured; then, when the density of the battery electrolyte changes, the corresponding spectral central wavelength also shifts, and the battery array electrolyte density value can be calculated according to the pre - calibrated second performance change relationship.

[0092] For obtaining the battery gas concentration value, first, a third performance change relationship between the battery gas concentration and its corresponding spectral absorption intensity needs to be pre - calibrated: A series of spectral absorption intensities corresponding to signals at known gas concentrations collected through the gas absorption chamber are obtained, and a linear fitting function y4 = a4 * c + b4 is obtained, where y4 is the spectral absorption intensity, c is the gas concentration, and a4 and b4 are fitting coefficients, as Figure 7 (d); according to the above linear fitting function, the third performance change relationship can be obtained as: c’ = (y4’ - b4) / a4, where y4’ is the absorption intensity of the spectrum corresponding to the gas absorption chamber obtained in the actual measurement, and c’ is the gas concentration value to be measured; then, when the battery gas concentration changes, the corresponding spectral absorption intensity also changes, and the battery array gas concentration value can be calculated according to the pre - calibrated third performance change relationship.

[0093] In this embodiment, optionally, after step six, there is also step seven: setting a temperature threshold, an electrolyte density threshold, and a gas concentration threshold, and giving an alarm when the battery temperature value exceeds the temperature threshold, the battery electrolyte density value exceeds the electrolyte density threshold, and the battery gas concentration value exceeds the gas concentration threshold.

[0094] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field understand that, within the scope of the present invention thus described, other embodiments can be envisioned. Regarding the scope of the present invention, the disclosure of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

Claims

1. A multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system, characterized in that: It includes a data acquisition subsystem and a data processing subsystem, and the output of the data acquisition subsystem is connected to the input of the data processing subsystem; wherein, The data acquisition subsystem includes a tunable light source, a multi-parameter signal acquisition module and a data acquisition card. The tunable light source is used to output laser light. The tunable light source is connected to the multi-parameter signal acquisition module. The multi-parameter signal acquisition module is used to acquire a first signal including battery temperature, electrolyte density inside the battery, and battery gas concentration data in the battery array, and send the first signal to the data acquisition card; The multi-parameter signal acquisition module consists of: a first fiber optic coupler, an optical fiber circulator, a second fiber optic coupler, a polarization beam splitter, a multi-parameter sensing unit group, a first photodetector and a second photodetector; the input port of the first fiber optic coupler is connected to the tunable light source, and the output ports are respectively connected to the input port of the second fiber optic coupler and the first port of the optical fiber circulator; the second port of the optical fiber circulator is connected to the multi-parameter sensing unit group, and the third port is connected to the input port of the second fiber optic coupler; the output port of the second fiber optic coupler is connected to the input port of the polarization beam splitter; the output ports of the polarization beam splitter are respectively connected to the input ports of the first photodetector and the second photodetector; the output ports of the first photodetector and the second photodetector are both connected to the data acquisition channels of the data acquisition card; Wherein, the multi-parameter sensing unit group includes multiple groups of sensing units connected in parallel and composed of a beam splitting coupler and a multi-parameter sensing probe; wherein, the output port of the beam splitting coupler of each group is respectively connected to the multi-parameter sensing probe of this group and the input port of the beam splitting coupler of the next group.

2. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 1, characterized in that: The multi-parameter sensing probe consists of a fiber Bragg grating, a fiber Fabry-Perot cavity and a gas absorption chamber; wherein, the fiber Fabry-Perot cavity is a hollow cavity and is not closed.

3. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 2, characterized in that: The included angle between the fiber optic main axis of the output port of the second fiber optic coupler and the fiber optic main axis of the input port of the polarization beam splitter is 45°.

4. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 3, characterized in that: The data acquisition subsystem further includes a total fiber optic coupler and a light source instantaneous frequency signal acquisition module. The input port of the total fiber optic coupler is connected to the tunable light source, and the output port is connected to the light source instantaneous frequency signal acquisition module; the light source instantaneous frequency signal acquisition module is used to acquire a second signal corresponding to the instantaneous frequency of the tunable light source. The light source instantaneous frequency signal acquisition module consists of: an auxiliary fiber optic coupler, an auxiliary delay optical fiber, a first Faraday rotator, a second Faraday rotator and a third photodetector. The input port of the auxiliary fiber optic coupler is connected to the total fiber optic coupler, the output ports are respectively connected to one end of the auxiliary delay optical fiber and the second Faraday rotator, the reflection port is connected to the input port of the third photodetector, the other end of the auxiliary delay optical fiber is connected to the first Faraday rotator, and the output port of the third photodetector is connected to the data acquisition channels of the data acquisition card.

5. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 4, characterized in that: The data acquisition subsystem further includes a gas reference spectrum signal acquisition module, which is used to acquire a third signal after the laser emitted by the tunable light source is absorbed by gas molecules. The gas reference spectrum signal acquisition module consists of a gas cell and a fourth photodetector; The gas cell is respectively connected to the output port of the total fiber coupler and the input port of the fourth photodetector, and the output port of the fourth photodetector is connected to the data acquisition channel of the data acquisition card.

6. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 5, characterized in that: The data processing subsystem includes a storage module, a light source phase noise compensation module, a light source wavelength calibration module, a multi-parameter spectrum demodulation module, a temperature value acquisition module, an electrolyte density value acquisition module, and a gas concentration value acquisition module; among them, The storage module is used to store the first performance change relationship between the pre-calibrated battery temperature and its corresponding spectral center wavelength, the second performance change relationship between the battery electrolyte density and its corresponding spectral center wavelength, the third performance change relationship between the battery gas concentration and its corresponding spectral absorption intensity, and the standard gas absorption spectrum; The light source phase noise compensation module is used to perform noise compensation on the first signal and the third signal by using the acquired second signal; the specific process includes: preprocessing the acquired second signal to obtain the instantaneous phase of the second signal, and using the instantaneous phase to resample the first signal and the third signal to obtain the corresponding first resampled signal and third resampled signal after phase noise compensation; The light source wavelength calibration module is used to calibrate the first resampled signal by using the standard gas absorption spectrum and the third resampled signal; the specific process includes: first, identifying the center wavelengths of two absorption peaks in the third resampled signal according to the center wavelengths of two absorption peaks in the standard gas absorption spectrum; then, calculating the scaling factor and the translation factor according to the center wavelengths; among them, the calculation expressions for the scaling factor α and the translation factor β are: In the formula, λ1 and λ2 represent the center wavelengths of two absorption peaks in the standard gas absorption spectrum; λ1′ and λ2′ represent the center wavelengths of two absorption peaks in the third resampled signal; finally, calibrating the first resampled signal according to the scaling factor α and the translation factor β; The multi-parameter spectrum demodulation module is used to demodulate the calibrated first resampled signal to obtain the first center wavelength in the spectral data corresponding to the fiber Bragg grating in each multi-parameter sensing probe, the second center wavelength in the spectral data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber; The temperature value acquisition module is used to calculate and obtain the battery temperature value according to the first performance change relationship and the first center wavelength; The electrolyte density value acquisition module is used to calculate and obtain the electrolyte density value according to the second performance change relationship, the second center wavelength, and the battery temperature value; The gas concentration value acquisition module is used to calculate and obtain the battery gas concentration value according to the third performance change relationship and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

7. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 6, characterized in that: The process of demodulating the corrected first resampled signal in the multi-parameter spectrum demodulation module includes: First, perform a fast Fourier transform on the corrected first resampled signal to obtain the reflection peaks corresponding to the fiber Bragg gratings, fiber Fabry-Perot cavities, and gas absorption chambers connected in each multi-parameter sensing probe; Then, select the reflection peaks corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber for inverse Fourier transform to obtain the spectral data corresponding to each fiber Bragg grating, fiber Fabry-Perot cavity, and gas absorption chamber, so as to obtain the first central wavelength, the second central wavelength, and the absorption intensity of the spectrum corresponding to the gas absorption chamber.

8. The multi-parameter distributed optical fiber sensing system for monitoring a battery array of an energy storage system according to claim 7, characterized in that: The system further includes a display and alarm subsystem, which is used to display the battery array temperature value, electrolyte density value, and gas concentration value in real time, and set temperature thresholds, electrolyte density thresholds, and gas concentration thresholds to give an alarm when the temperature value exceeds the temperature threshold, the electrolyte density value exceeds the electrolyte density threshold, and the gas concentration value exceeds the gas concentration threshold.

9. A multi-parameter distributed optical fiber sensing method for monitoring a battery array of an energy storage system, characterized in that, It includes the following steps: Step 1: Immerse the probes of multiple groups of multi-parameter sensing probes into the electrolyte of the battery array; The multi-parameter sensing probe includes a fiber Bragg grating, a fiber Fabry-Perot cavity, and a gas absorption chamber; among them, the fiber Fabry-Perot cavity is a cavity and is not closed; Step 2: Collect a first signal including battery temperature, electrolyte density inside the battery, and battery gas concentration data in the battery array, a second signal corresponding to the instantaneous frequency of the tunable light source, and a third signal after the laser emitted by the tunable light source is absorbed by gas molecules; Step 3: Use the second signal to perform noise compensation on the first signal and the third signal to obtain a noise-compensated first resampled signal and a third resampled signal; Step 4: Use the standard gas absorption spectrum and the third resampled signal to correct the first resampled signal to obtain a corrected first resampled signal; Step 5: Perform demodulation processing on the corrected first resampled signal to obtain the first central wavelength in the spectral data corresponding to the fiber Bragg grating in each group of multi-parameter sensing probes, the second central wavelength in the spectral data corresponding to the fiber Fabry-Perot cavity, and the absorption intensity of the spectrum corresponding to the gas absorption chamber; Step 6: Calculate and obtain the battery temperature value according to the first central wavelength and the pre-calibrated first performance change relationship; Calculate and obtain the electrolyte density value according to the second central wavelength, the battery temperature value, and the pre-calibrated second performance change relationship; Calculate and obtain the battery gas concentration value according to the absorption intensity of the spectrum corresponding to the gas absorption chamber and the pre-calibrated third performance change relationship.

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