A hybrid monitoring battery structure health system based on fiber optic spr and fbg sensors

Abstract

The application discloses a kind of hybrid monitoring battery structure health system based on optical fiber SPR and FBG sensor, including broadband light source, first optical fiber circulator, first optical fiber coupler, second optical fiber circulator, first signal transmission optical fiber, second signal transmission optical fiber, third signal transmission optical fiber, battery, first FBG sensor, second FBG sensor, third FBG sensor, optical fiber SPR sensor, light detector, second optical fiber coupler, optical spectrum analyzer and computer.The application is first implanted in the inside of battery with optical fiber SPR sensor and optical fiber FBG sensor, and simultaneously, two FBG sensors are pasted on the surface of battery;Then, the refractive index change of battery electrolyte is monitored by optical fiber SPR sensor, and the stress strain and temperature change of battery electrolyte and electrode are monitored by FBG sensor;Finally, optical signal is converted into electrical signal by light detector, and it is transmitted to optical spectrum analyzer and computer, so as to realize the health monitoring of battery inside.

Description

TECHNICAL FIELD

[0001] The application relates to a hybrid monitoring battery structure health system based on an optical fiber SPR and FBG sensor, and belongs to the technical fields of optical fiber grating sensing and battery health monitoring. BACKGROUND

[0002] As important electronic devices, batteries have played a vital role in consumer electronics, electric vehicles, intermittent renewable energy such as wind and solar, and storage of nuclear energy. With the wide application of batteries, their reliability, life, volume energy density and safety have become the focus of attention. The product quality and safety of batteries are directly related to the user experience, and even life safety, and advanced battery performance monitoring technology can provide an effective means to improve the use quality of batteries. At present, the performance monitoring of batteries mainly adopts external detection technology, however, in the terminal detection of batteries, although sensors for temperature, strain and other sensing technologies have been developed, these sensors are usually only attached to the outside of the battery, the response is lagging, and the complex electrochemical reaction process inside the battery cannot be sensed. Therefore, it is crucial to develop a sensing technology that can be implanted in the battery.

[0003] Optical fiber sensors have the advantages of small volume, small fusion loss, full compatibility with optical fibers, and can be embedded in intelligent materials, and their resonance wavelength is sensitive to changes in temperature, strain, refractive index, concentration and other external environments, and have been widely used in fiber lasers, optical fiber communication and various sensing fields. Due to the low invasiveness (chemical inertness), small volume, electromagnetic interference resistance and insulator characteristics of the optical fiber sensor, it has a wide application prospect in the field of battery structure health monitoring.

[0004] One of the focuses of lithium-ion battery health monitoring is the measurement of heat generation rate during operation. Due to high power input or output, lithium-ion batteries will experience significant temperature rise or thermal runaway during use, and the accumulated heat in the battery will cause performance degradation and safety hazards. For example, under adverse conditions such as overcharge / discharge and short circuit, hot spots will occur in individual batteries, eventually leading to rapid rise in internal temperature and pressure and causing explosion and combustion. Therefore, it is very important to quantitatively measure the heat generation rate of the battery under normal and adverse conditions. At present, for the thermal monitoring of lithium-ion batteries, thermocouples or electromechanical sensors are usually used on their surface.

[0005] Another focus of lithium-ion battery health detection is the volume change during operation. The chemical and mechanical stress generated by the electrode during the charging and discharging process of the lithium-ion battery, and the volume change of the electrode material caused thereby are the factors affecting the cycle life of the battery. At present, through in-situ means such as electrochemical transmission electron microscopy and atomic force microscopy, the changes in the morphology of the electrode material (such as cracking, collapse, etc.) caused by stress during the charging and discharging process of the battery can be directly observed, but these devices are expensive and require special test samples, and are difficult to use for commercial purposes. At the microscale, especially for the detection of stress changes inside the battery, there is still a lack of effective technical means.

[0006] Therefore, it is of important theoretical and application value to develop a system capable of meeting the real-time monitoring of battery health, including the temperature, stress and ion concentration changes inside the battery. SUMMARY

[0007] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a hybrid monitoring battery structural health system based on fiber SPR and FBG sensors. A plurality of FBG sensors and SPR sensors are implanted in the electrolyte, electrode, electrode and electrolyte interface inside the battery or attached to the surface of the battery. The stress and strain, temperature, electrolyte refractive index or concentration change inside the battery and the electrode surface temperature change are monitored respectively. The structural health monitoring of the battery is realized through signal modulation and demodulation. The present application has application prospects in the field of battery health detection.

[0008] To achieve the above purpose, the present application is implemented by using the following technical scheme:

[0009] The present application provides a hybrid monitoring battery structural health system based on fiber SPR and FBG sensors, comprising:

[0010] a broadband light source, a first fiber optic circulator, a first fiber optic coupler, a second fiber optic circulator, a first signal transmission optical fiber, a second signal transmission optical fiber, a third signal transmission optical fiber, a battery, a light detector, a second fiber optic coupler, a spectrum analyzer, a computer, a first FBG sensor, a fiber SPR sensor, a second FBG sensor, and a third FBG sensor, wherein:

[0011] The broadband light source is fixedly connected with the first fiber optic circulator;

[0012] The rear end of the first fiber optic circulator is connected with the first fiber optic coupler and the light detector respectively;

[0013] The first fiber optic coupler is connected with three second fiber optic circulators and the first, second and third signal transmission optical fibers in sequence;

[0014] The first signal transmission fiber, the second signal transmission fiber, and the third signal transmission fiber are respectively connected to the first FBG sensor, the fiber optic SPR sensor, and the second FBG sensor, wherein:

[0015] The first FBG sensor and the fiber optic SPR sensor are placed in the internal electrolyte of the battery. The second FBG sensor and the third FBG sensor are connected in series and attached to the outer surface of the battery. The second FBG sensor is located on the positive electrode surface of the battery, and the third FBG sensor is located on the negative electrode surface of the battery.

[0016] The first, second, and third signal transmission optical fibers pass through the battery and are connected to the three photodetectors respectively.

[0017] The photodetector is fixedly connected to the second fiber optic coupler, the spectrometer, and the computer in sequence.

[0018] Furthermore, the structure of the fiber optic SPR sensor is based on a Cu-unclad fiber optic SPR sensor, with a sensing layer length of 13~17 mm and a metal thin film thickness of 40 nm, 50 nm, or 60 nm. The fiber optic SPR sensor can monitor the change in the refractive index of the electrolyte with concentration.

[0019] Furthermore, the first FBG sensor, the second FBG sensor, and the third FBG sensor have different center wavelengths, which are used for monitoring battery temperature and positive and negative electrode stress and strain, respectively.

[0020] Furthermore, the battery is any one of lithium-ion batteries, sodium-ion batteries, lead-acid batteries, air batteries, sodium-sulfur batteries, and nickel-based batteries.

[0021] Furthermore, the electrolyte inside the battery is any one of a liquid electrolyte, a colloidal electrolyte, or a solid electrolyte.

[0022] Furthermore, the first signal transmission fiber, the second signal transmission fiber, and the third signal transmission fiber are core-cladding structure single-mode silica fibers with a core refractive index of 1.4680 and a diameter of 9.0 μm, a cladding refractive index of 1.4512 and a diameter of 125 μm, a coating diameter of 250 mm, and a numerical aperture of 0.22.

[0023] Furthermore, the first signal transmission optical fiber is connected to the front and rear ends of the optical fiber SPR sensor respectively, and is used to transmit the optical signal of the sensor.

[0024] The second signal transmission optical fiber is connected to the front and rear ends of the first FBG sensor respectively, and is used to transmit the optical signal of the sensor.

[0025] The third signal transmission optical fiber connects the second FBG sensor and the third FBG sensor in series, and is used for conducting optical signals of the two sensors.

[0026] Further, the broadband light source is any one of an SLD broadband light source, an ASE broadband light source or an SLED broadband light source, and provides laser with a wavelength range of 1510nm-1590nm.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The present application provides a hybrid monitoring battery structure health system based on fiber SPR and FBG sensors, which implants multiple FBG sensors and SPR sensors in the electrolyte, the electrode, the electrode and electrolyte interface inside the battery or pastes on the surface of the battery, respectively monitors the stress and strain, the electrolyte refractive index change and the electrode temperature change inside the battery, and realizes the structure health monitoring of the battery through system analysis. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a system schematic diagram for monitoring battery structure health based on fiber SPR sensors and FBG sensors;

[0030] Figure 2 It is a layout schematic diagram of fiber SPR sensors and FBG sensors in the battery interior and surface;

[0031] Figure 3 It is a FBG sensor structure schematic diagram;

[0032] Figure 4 It is a fiber SPR sensor structure schematic diagram;

[0033] Figure 5 It is a FBG sensor wavelength drift schematic diagram;

[0034] Figure 6 It is a center wavelength and transmission intensity change curve diagram of the fiber SPR sensor under different concentrations.

[0035] In the figure: 1, broadband light source; 2, first optical fiber circulator; 3, first optical fiber coupler; 4, second optical fiber circulator; 5, first signal transmission optical fiber; 6, second signal transmission optical fiber; 7, third signal transmission optical fiber; 8, battery; 9, optical detector; 10, second optical fiber coupler; 11, optical spectrum analyzer; 12, computer; 81, first FBG sensor; 82, fiber SPR sensor; 83, second FBG sensor; 84, third FBG sensor. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example

[0037] like Figure 1 As shown, this embodiment introduces a hybrid monitoring system for battery structural health based on fiber optic SPR and FBG sensors, including: a broadband light source 1, a first fiber optic circulator 2, a first fiber optic coupler 3, a second fiber optic circulator 4, a first signal transmission fiber 5, a second signal transmission fiber 6, a third signal transmission fiber 7, a battery 8, a photodetector 9, a second fiber optic coupler 10, a spectrum analyzer 11, a computer 12, a first FBG sensor 81, a fiber optic SPR sensor 82, a second FBG sensor 83, and a third FBG sensor 84. Here:

[0038] The broadband light source 1 is fixedly connected to the first fiber optic circulator 2;

[0039] The rear end of the first fiber optic circulator 2 is connected to the first fiber optic coupler 3 and the photodetector 9, respectively.

[0040] The first fiber optic coupler 3 is connected in sequence to three second fiber optic circulators 4, as well as the first signal transmission fiber 5, the second signal transmission fiber 6, and the third signal transmission fiber 7.

[0041] The first signal transmission fiber 5, the second signal transmission fiber 6, and the third signal transmission fiber 7 are respectively connected to the first FBG sensor (81), the fiber optic SPR sensor (82), and the second FBG sensor (83).

[0042] The first signal transmission fiber 5, the second signal transmission fiber 6, and the third signal transmission fiber 7 pass through the battery 8 and are connected to the three photodetectors 9 respectively.

[0043] The photodetector 9 is fixedly connected to the second fiber optic coupler 10, the spectrometer 11 and the computer (12) in sequence.

[0044] like Figure 2 As shown, the first FBG sensor 81 ( Figure 3 ), Fiber optic SPR sensor 82 ( Figure 4 The second FBG sensor 83 is embedded in the electrolyte of the battery 8, that is, it is located inside the battery 8. The second FBG sensor 83 and the third FBG sensor 84 are connected in series and are surface-mounted on the surface of the battery 8. The second FBG sensor 83 is located on the positive electrode surface of the battery 8, and the third FBG sensor 84 is located on the negative electrode surface of the battery 8.

[0045] As an embodiment, when the battery 8 has a structural health problem, the concentration of the electrolyte of the battery 8 will change, and the temperature of the positive and negative electrodes will rise, and the strain near the electrodes will occur, at this time, due to the changes of the temperature and stress strain, the center wavelengths of the first FBG sensor 81, the second FBG sensor 83, and the third FBG sensor 84 will drift as shown in Figure 5 Due to the change of the electrolyte concentration, the output spectrum of the fiber SPR sensor 82 will change as shown in Figure 6 .

[0046] As an embodiment, as shown in Figure 3 , the center wavelengths of the first FBG sensor 81, the second FBG sensor 83, and the third FBG sensor 84 are 1530 nm, 1540 nm, and 1550 nm respectively, which are used for monitoring the battery temperature and the stress strain of the positive and negative electrodes of the battery respectively.

[0047] As an embodiment, as shown in Figure 4 , the fiber SPR sensor 82 is located in the electrolyte of the battery 8, and its specific structure is a Cu-unclad fiber SPR sensor based on a sensing layer length of 15 mm and a sensing layer metal film thickness of 50 nm. The sensor is used to monitor the concentration change of the refractive index of the electrolyte.

[0048] As an embodiment, the battery is a lithium ion battery, and the electrolyte is a liquid electrolyte.

[0049] As an embodiment, the first signal transmission fiber 5, the second signal transmission fiber 6, and the third signal transmission fiber 7 are core-clad structure single-mode quartz optical fibers, with a core refractive index of 1.4680, a diameter of 9.0 μm, a cladding refractive index of 1.4512, a diameter of 125 μm, a coating layer diameter of 250 mm, and a numerical aperture of 0.22, wherein:

[0050] The first signal transmission fiber 5 is connected to the front end and the rear end of the fiber SPR sensor 82 respectively, for conducting the optical signal of the sensor;

[0051] The second signal transmission fiber 6 is connected to the front end and the rear end of the first FBG sensor 81 respectively, for conducting the optical signal of the sensor;

[0052] The third signal transmission fiber 7 connects the second FBG sensor 83 and the third FBG sensor 84 in series, for conducting the optical signals of the two sensors.

[0053] As an embodiment, the broadband light source 1 is an Automatic Stabilization Equipment (ASE) broadband light source, which provides laser with a wavelength range of 1510nm-1590nm.

[0054] The application provides a hybrid monitoring battery 8 structure health system based on fiber SPR and FBG sensors, which implants multiple FBG sensors and SPR sensors into electrolyte, electrodes, electrode and electrolyte interfaces or pastes on the surface of the battery 8, respectively monitors stress and strain, electrolyte refractive index change and electrode temperature change in the battery 8, and realizes the structure health monitoring of the battery 8 through system analysis, and has application prospect in the health detection field of the battery 8.

[0055] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the technical principles of the present application, several improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A hybrid monitoring battery structure health system based on fiber optic SPR and FBG sensors, characterized in that, The application relates to a battery temperature and stress-strain monitoring system, which comprises the following components: a broadband light source (1), a first optical fiber circulator (2), a first optical fiber coupler (3), a second optical fiber circulator (4), a first signal transmission optical fiber (5), a second signal transmission optical fiber (6), a third signal transmission optical fiber (7), a battery (8), a light detector (9), a second optical fiber coupler (10), a spectrum analyzer (11), a computer (12), a first FBG sensor (81), a fiber SPR sensor (82), a second FBG sensor (83) and a third FBG sensor (84), wherein: the broadband light source (1) is fixedly connected with the first optical fiber circulator (2); the rear end of the first optical fiber circulator (2) is connected with the first optical fiber coupler (3) and the light detector (9) respectively; the first optical fiber coupler (3) is sequentially connected with three second optical fiber circulators (4) and the first signal transmission optical fiber (5), the second signal transmission optical fiber (6) and the third signal transmission optical fiber (7); the first signal transmission optical fiber (5), the second signal transmission optical fiber (6) and the third signal transmission optical fiber (7) are connected with the first FBG sensor (81), the fiber SPR sensor (82) and the second FBG sensor (83) respectively, wherein: the first FBG sensor (81) and the fiber SPR sensor (82) are arranged in the internal electrolyte of the battery (8), the second FBG sensor (83) and the third FBG sensor (84) are arranged on the outer surface of the battery (8) in series, the second FBG sensor (83) is arranged on the positive electrode surface of the battery (8), and the third FBG sensor (84) is arranged on the negative electrode surface of the battery (8); the first signal transmission optical fiber (5), the second signal transmission optical fiber (6) and the third signal transmission optical fiber (7) are connected with three light detectors (9) after penetrating through the battery (8); the light detectors (9) are fixedly connected with the second optical fiber coupler (10), the spectrum analyzer (11) and the computer (12) in sequence; the fiber SPR sensor (82) is a Cu-unclad fiber SPR sensor, the first FBG sensor (81), the second FBG sensor (83) and the third FBG sensor (84) have different central wavelengths and are used for monitoring the temperature and stress-strain of the battery, and the first signal transmission optical fiber (5), the second signal transmission optical fiber (6) and the third signal transmission optical fiber (7) are core-clad structure single-mode quartz optical fibers. The length of the fiber SPR sensor (82) is 13-17 mm, the thickness of the sensing layer metal film is any one of 40 nm, 50 nm and 60 nm, and the fiber SPR sensor can monitor the change of the refractive index of the electrolyte with the concentration. The battery (8) is any one of a lithium ion battery, a sodium ion battery, a lead-acid battery, an air battery, a sodium-sulfur battery and a nickel-based battery. The electrolyte in the battery (8) is any one of a liquid electrolyte, a gel electrolyte and a solid electrolyte. ​ ​ ​ ​ ​ 2. The hybrid monitoring battery structure health system based on fiber-optic SPR and FBG sensors according to claim 1, wherein, ​ 3.The hybrid monitoring system for battery structure health based on optical fiber SPR and FBG sensors according to claim 1, wherein, ​ 4. The system according to claim 3, wherein the system is characterized by, ​ 5.The hybrid monitoring system for battery structure health based on optical fiber SPR and FBG sensors according to claim 1, wherein, The core refractive index of the first signal transmission fiber (5), the second signal transmission fiber (6) and the third signal transmission fiber (7) is 1.4680, the diameter is 9.0 μm, the cladding refractive index is 1.4512, the diameter is 125 μm, the coating layer diameter is 250 mm, and the numerical aperture is 0.

22.

6. The system according to claim 5, wherein the system is characterized by, The first signal transmission fiber (5) is connected with the front end and the rear end of the fiber SPR sensor (82) respectively, and is used for conducting the optical signal of the sensor; The second signal transmission fiber (6) is connected with the front end and the rear end of the first FBG sensor (81) respectively, and is used for conducting the optical signal of the sensor; The third signal transmission fiber (7) connects the second FBG sensor (83) and the third FBG sensor (84) in series, and is used for conducting the optical signal of the two sensors. 7.The hybrid monitoring system for battery structure health based on fiber SPR and FBG sensors according to claim 1, wherein, The broadband light source (1) is any one of an SLD broadband light source, an ASE broadband light source or an SLED broadband light source, and provides laser with a wavelength range of 1510 nm-1590 nm.

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