CN113078375B - Battery monitoring system and monitoring method - Google Patents

Abstract

The invention discloses a battery monitoring system and a monitoring method, comprising a multi-wavelength light source, a wavelength division multiplexer, a light guide fiber unit and a spectrum scanner, wherein the multi-wavelength light source is used for providing a multi-wavelength detection optical signal, and the spectrum scanner is used for receiving and processing a response optical signal output by the light guide fiber; the multi-wavelength detection optical signal is injected into the optical fiber unit through the wavelength division multiplexer, and the response optical signal output by the optical fiber is processed through the spectrum scanner. The invention introduces the micro-nano light guide fiber detection technology into the battery safety early warning field, and realizes the in-situ monitoring of a plurality of parameters such as the internal pressure, temperature, strain, dendritic crystal growth process and the like of the battery.

Description

A battery monitoring system and monitoring method

technical field

The invention relates to the battery field, in particular to a battery monitoring system and a monitoring method.

Background technique

Lithium batteries are the main direction for the development of next-generation green new energy. Most of the existing commercial batteries are lithium-ion batteries. In order to obtain higher battery efficiency, lithium batteries are the preferred object of the next-generation batteries. However, lithium batteries are prone to grow dendrites after a large number of cycles or in extreme environments where the working environment is unstable. Once the dendrites pierce the separator, the battery will short-circuit and even cause the battery to explode, posing a greater safety hazard. .

The separator is a key part inside the battery, located between the positive and negative electrodes of the battery. Its function is: on the one hand, it separates the materials of the positive and negative electrodes to prevent short circuit due to the contact between the positive and negative electrodes; on the other hand, it keeps the electrolyte The ions in the battery pass through the diaphragm to complete the charging and discharging process. However, in situ monitoring of dendrites and their growth process has not been realized yet.

Contents of the invention

Purpose of the invention: The purpose of the invention is to provide a battery monitoring system and monitoring method, which can realize high-precision, in-situ and real-time monitoring of the internal environment of the battery.

Technical solution: A battery monitoring system of the present invention, which includes a multi-wavelength light source, a wavelength division multiplexer, an optical fiber unit, and a spectrum scanner. The multi-wavelength light source is used to provide multi-wavelength detection optical signals, and the spectrum scanner is used to provide Receiving and processing the response optical signal output by the optical fiber; the multi-wavelength detection optical signal is injected into the optical fiber unit through the wavelength division multiplexer, and the response optical signal output by the optical fiber is processed by the spectrum scanner.

The monitoring system of the present invention adopts a multi-wavelength light source, and the light source is connected to a wavelength division multiplexer, and the wavelength division multiplexer couples multiple wavelength signals to multiple optical fibers, so that the signals of each wavelength are used for safety warnings monitor. Embedding the system in the battery diaphragm can improve the spatial resolution of the sensor and more comprehensively monitor the dendrite growth process inside the battery and the regional distribution of parameters such as temperature and pressure inside the battery. The principle of the present invention to improve the spatial resolution and the measurement accuracy of the internal parameters of the battery is as follows: on the one hand, multiple light guide fibers are embedded in the diaphragm in parallel or in a grid shape, and the light guide fibers cover the entire diaphragm coverage area, so the covered area of the light guide fibers can be monitored. On the other hand, the structural units embedded in the optical fiber itself make the optical fiber very sensitive to changes in the surrounding environment, and can monitor various parameters to be measured such as temperature, pressure, and dendrite growth process.

The present invention adopts the following technical solutions to improve the spatial resolution and the measurement accuracy of the internal parameters of the battery: the method uses the optical fiber and the microstructure made on the optical fiber as the physical quantity sensing element in the sensing system, and the optical fiber is also used for signal transmission Medium, the front-end signal source outputs multi-wavelength laser signals, and the wavelength division multiplexer (WDM) is used to inject the signals of each wavelength into multiple optical fibers to monitor the status of different areas, and each response signal is output through WDM respectively to the spectrometer to obtain monitoring results in real time.

Among them, the light guide fiber unit is arranged at the position to be monitored, and the light guide fiber unit includes a number of parallel or crossed light guide fibers; the cross arrangement can adopt a well-shaped network structure, wherein the light guides in different directions in the well-shaped network structure The angle between the fibers can be between 0-180 degrees, which is properly selected according to the actual application scenario.

Preferably, the optical fiber unit includes a plurality of optical fibers, the diameter of each optical fiber is less than 125 μm, that is, the size of the optical fiber is in the field of micro-nano size, and its diameter is less than 125 μm, and the micro-nano optical fiber is sensitive to the surrounding refractive index , once dendrite growth occurs, the refractive index environment of the optical fiber will change, so in-situ real-time monitoring of the dendrite growth process can be realized.

Optionally, there are microstructures (grating, FP cavity, V-shaped groove, inclined groove and other structures on the optical fiber, and the surface of the structure can be plated with sensitizing materials), and the microstructure on the optical fiber can be used for temperature, pressure, strain Monitoring of other parameters.

The surface of the optical fiber is covered with an anti-corrosion layer to prevent the optical fiber from being corroded by the electrolyte; in addition, a sensitizing material can be coated on the optical fiber to improve the accuracy of parameter measurement.

Wherein, the above-mentioned optical fiber unit includes several optical fibers arranged in parallel, and the wavelength division multiplexer includes a first wavelength division multiplexer and a second wavelength division multiplexer; the output end of the multi-wavelength light source is connected to the first wavelength division multiplexer connected to the input end of the device, the output end of the first wavelength division multiplexer is connected to one end of the optical fiber, the other end of the optical fiber is connected to the input end of the second wavelength division multiplexer, and the second wavelength division multiplexer The output of the detector is connected to the input of the spectrum scanner.

Optionally, the above-mentioned monitoring system also includes a circulator, the optical fiber unit includes several optical fibers arranged in parallel, the output end of the multi-wavelength light source is connected to the a port of the circulator, and the b port of the circulator is connected to the wavelength division multiplexer The other end of the wavelength division multiplexer is connected with the optical fiber, and the c port of the circulator is connected with the spectrum scanner.

The monitoring system can choose the following four types of structures:

(1) The monitoring system includes a multi-wavelength light source, a wavelength division multiplexer, a spectral scanner, a data acquisition and analysis unit, and the optical fiber is distributed in parallel; the specific optical path is: the output of the multi-wavelength light source is connected to the first wavelength division At the input end of the multiplexer, the first wavelength division multiplexer decomposes multiple wavelengths respectively to connect to the optical fibers F ₁ ～F _m , and discrete microstructures are made on the optical fibers F ₁ ～F _m , each The output of the optical fiber is connected to the input port of the second wavelength division multiplexer, the output port of the second wavelength division multiplexer is connected to the spectrum scanner, and the spectrum scanner is connected to the data acquisition and analysis unit.

The monitoring method specifically includes the following steps:

Step 1. Multi-wavelength detection optical signals are demultiplexed by the first wavelength division multiplexer and injected into each optical fiber respectively, and the response optical signals output by each optical fiber are combined by the second wavelength division multiplexer and output to the spectrum scanner ;

Step 2. The spectrum scanner processes the received signal, and separately analyzes the event information carried by each wavelength signal. Events such as pressure, temperature, strain, dendrite length, etc.;

Step 3, comprehensively analyzing the measurement results of multiple wavelength signals to determine the location where each event occurs, the size of the signal, the size of the area covered by the event, and the like.

(2) Based on the first multi-wavelength light source, the first wavelength division multiplexer, the second wavelength division multiplexer, the first spectral scanner, the second wavelength light source, the third wavelength division multiplexer, and the fourth wavelength division multiplexer A user, a second spectrum scanner, a data acquisition and analysis unit, and a structure in which the optical fiber is distributed in a grid; the specific optical path is: in the horizontal direction, the output of the first multi-wavelength light source is connected to the input of the first wavelength division multiplexer At the end, the first wavelength division multiplexer decomposes multiple wavelengths to connect to the optical fibers F ₁ ～F _m . Discrete microstructures are made on the optical fibers F ₁ ～F _m , and the output of each optical fiber Connect the input port of the second wavelength division multiplexer, the output port of the second wavelength division multiplexer is connected to the first spectrum scanner; on the vertical direction: the output of the second multi-wavelength light source is connected to the third wavelength division multiplexer At the input end, the third wavelength division multiplexer decomposes multiple wavelengths respectively to connect to the optical fibers F ₁ ~ F _n . Discrete microstructures are made on the optical fibers F ₁ ~ F _n , and each optical fiber The output is connected to the input port of the fourth wavelength division multiplexer, the output port of the fourth wavelength division multiplexer is connected to the second spectrum scanner, and both the first spectrum scanner and the second spectrum scanner are connected to the data acquisition and analysis unit. The light guide fibers in the horizontal and vertical directions are distributed in a grid pattern.

(3) Based on the structure of multi-wavelength light source, circulator, wavelength division multiplexer, spectral scanner, and data acquisition and analysis unit; the specific optical path is: the output of the multi-wavelength light source is connected to the a port of the circulator, and the b port of the circulator is connected to the wave The input end of the division multiplexer, the wavelength division multiplexer decomposes multiple wavelengths to connect to the optical fiber F ₁ ~F _m , and the optical fiber F ₁ ~F _m is made with discrete microstructures, and the circulator The c port is connected to the spectrum scanner, and the spectrum scanner is connected to the data acquisition and analysis unit.

(4) The system structure includes a first multi-wavelength light source, a first circulator, a first wavelength division multiplexer, a first spectral scanner, a second multi-wavelength light source, a second circulator, a second wavelength division multiplexer, The structure of the second spectral scanner, data acquisition and analysis unit, the specific optical path is: the output of the first multi-wavelength light source is connected to the a port of the first circulator, and the b port of the first circulator is connected to the input end of the first wavelength division multiplexer , the first wavelength division multiplexer decomposes multiple wavelengths to connect to the optical fibers F ₁ ～F _m , and discrete microstructures are made on the optical fibers F ₁ ～F _m , and the c-port of the first circulator is connected to The first spectral scanner; the output of the second multi-wavelength light source is connected to the a port of the second circulator, and the b port of the second circulator is connected to the input end of the second wavelength division multiplexer, and the second wavelength division multiplexer combines multiple wavelengths Disassembled to connect to the optical fibers F ₁ ~ F _n respectively, discrete microstructures are made on the optical fibers F ₁ ~ F _n , the c port of the second circulator is connected to the second spectrum scanner; the first spectrum scanner and The second spectrum scanner is simultaneously connected to the data acquisition and analysis unit. The light guide fibers in the horizontal and vertical directions are distributed in a grid pattern.

Among them, the data acquisition and analysis unit can judge the change of the refractive index around the optical fiber according to the intensity change of each wavelength signal, determine the thickness of the dendrite growth, and judge the change of pressure and temperature according to the drift of the wavelength; and can pass Comprehensively analyze the measurement results of multiple optical fibers, distinguish each measurement signal, and confirm the signal type, such as pressure, temperature, or dendrite, and monitor the internal working process of the battery in real time and in a distributed manner.

The present invention also provides a monitoring method for the above-mentioned battery monitoring system, comprising the following steps:

(1) The optical fiber unit is arranged in the diaphragm area of the battery or embedded inside the diaphragm, and the optical fiber is output to the spectrum scanner;

(2) The spectrum scanner processes each received response optical signal, and separately analyzes the event information carried by each wavelength signal;

(3) Comparatively analyze the response optical signals of multiple optical fibers to determine the location where each event occurs and the size of the area covered by the event.

Preferably, the change of the refractive index around the optical fiber is obtained according to the change of the intensity of the optical signal in response to each wavelength, and the thickness of the dendrite growth is determined; the change of pressure and temperature is obtained according to the shift of the wavelength. And by comprehensively analyzing the measurement results of multiple optical fibers, each measurement signal can be distinguished, and the signal type can be confirmed, such as pressure, temperature or dendrite, etc. At the same time, the internal working process of the battery can be monitored in real time and distributed.

The present invention utilizes a multi-wavelength light source, a wavelength division multiplexer, a plurality of optical fibers arranged in parallel or intersecting, a circulator, and related optoelectronic accessories involved in the above devices, to realize real-time monitoring of the internal working state of the battery, and to timely provide warning sign. The sensing system designed in the present invention can be embedded in the battery diaphragm, improve the spatial resolution of battery monitoring, and more comprehensively monitor various parameters to be measured, such as temperature, pressure, strain, and dendrite growth process inside the battery.

In the present invention, the optical fiber sensing technology is applied to the monitoring and early warning of the battery. It is a kind of optical fiber sensing system based on the wavelength division utilization technology to monitor the safety of the battery. In situ monitoring. The technical difficulty of the present invention lies in the in-situ monitoring of the inside of the battery. It is necessary to feed back the data inside the battery in real time without affecting the efficiency of the battery. The battery itself is a sealed structure, and it is not easy to implant sensors. performance. The micro-nano optical fiber used in the present invention has the characteristics of small size, light weight, passive, and anti-electromagnetic interference. If it is embedded in the battery separator, the effect on battery efficiency is very weak, and the micro-nano optical fiber responds to changes in the surrounding refractive index. Very sensitive, very suitable for embedding the separator to realize the safety warning of the battery. Therefore, the present invention innovatively proposes to weave the micro-nano optical fiber into a well-shaped network, embed it in the diaphragm, and then use wavelength division multiplexing technology to monitor the battery diaphragm in situ to realize battery safety warning.

Beneficial effect:

The invention introduces the micro-nano optical fiber detection technology into the field of battery safety early warning, and realizes in-situ monitoring of multiple parameters such as internal pressure, temperature, strain, and dendrite growth process of the battery. The special structural form proposed by the present invention determines that it can realize fully distributed measurement inside the battery without affecting the ion penetration function of the diaphragm itself.

The system of the invention uses a multi-wavelength light source, and the multi-wavelength signals of the light source are decomposed by a wavelength division multiplexer and coupled to a plurality of optical fibers, so that the signals of each wavelength are used for safety early warning and monitoring. The system is embedded in the battery diaphragm, which can improve the spatial resolution of diaphragm monitoring and more comprehensively monitor the working process inside the battery. The invention has great significance in battery safety early warning.

Description of drawings

Figure 1 is a structural diagram of a wavelength division multiplexing sensing system in which optical fibers are distributed in parallel.

Fig. 2 is a structural diagram of a wavelength division multiplexing sensing system in which optical fibers are distributed in a grid pattern.

Fig. 3 is a structural diagram of a wavelength division multiplexing sensing system in which single-ended detection optical fibers are distributed in parallel.

Fig. 4 is a structural diagram of a wavelength division multiplexing sensing system in which single-ended detection optical fibers are distributed in a grid pattern.

detailed description

The present invention will be further described in detail below in conjunction with the examples.

The diameter of the optical fiber used in the following embodiments is less than 125 microns, and the wavelength range of the multi-wavelength light source used is between 260nm-4000nm.

Example 1:

The monitoring system of this embodiment is suitable for in-situ monitoring of batteries. As shown in Figure 1, the monitoring system of this embodiment includes a multi-wavelength light source 1, a wavelength division multiplexer 2, an optical fiber unit 3, and a wavelength division multiplexer 4 . Spectrum scanner 5. Data acquisition and analysis unit 6. The light guide fiber unit 3 includes m light guide fibers arranged in parallel, where m is a positive integer.

This embodiment adopts the wavelength division multiplexing sensing system, and the optical path connection mode of the system is as follows: the output of the multi-wavelength light source 1 is connected to the input end of the wavelength division multiplexer 2, and the wavelength division multiplexer 2 decomposes and connects multiple wavelengths respectively Optical fiber 3 (F ₁ ~F _m ), discrete microstructures are made on optical fiber 3 (F ₁ ~F _m ), the output of each optical fiber is connected to the input port of wavelength division multiplexer 4, and the wavelength division The output port of the multiplexer 4 is connected to the spectrum scanner 5, and the spectrum scanner 5 is connected to the data acquisition and analysis unit 6. The specific optical path is shown in FIG. 1 .

The specific monitoring process includes the following steps:

Step 1. The optical signals containing multiple wavelengths output by the multi-wavelength light source 1 are separated by the wavelength division multiplexer 1 and then respectively introduced into each optical fiber 3, and the signals containing sensing information output by the optical fiber are output to the wavelength division multiplexer. 4, the wavelength division multiplexer 4 summarizes the sensing information of each optical fiber to the spectrum scanner 5, and finally, the spectrum scanner 5 sends the signal to the data acquisition and analysis unit 6 for processing and analysis;

Step 2, the data acquisition and analysis unit 6 can judge the change of the refractive index around the optical fiber according to the intensity change of each wavelength signal on the one hand, and then determine the height of dendrite growth; on the other hand, judge the pressure and temperature according to the drift of the wavelength The change.

Step 3. Combining the measurement results of multiple optical fibers, and distinguishing the position of the signal point (pressure, temperature or dendrite) for each measurement signal, the working process inside the battery can be monitored in real time and in a distributed manner.

Example 2:

As shown in Figure 2, the monitoring system of this embodiment includes a first multi-wavelength light source 7, a first wavelength division multiplexer 8, a first optical fiber unit 9, a second wavelength division multiplexer 10, a first spectral scanning Instrument 11, second multi-wavelength light source 12, third wavelength division multiplexer 13, second optical fiber unit 14, fourth wavelength division multiplexer 15, second spectrum scanner 16, data acquisition and analysis unit 17. The first light guiding fiber unit 9 includes m light guiding fibers arranged in parallel in the horizontal direction, and the second light guiding fiber unit 14 includes n light guiding fibers arranged in parallel in the vertical direction, where m and n are positive integers.

The connection mode of the system optical path for sensing in this embodiment is as follows:

In the horizontal direction, the output terminal of the first multi-wavelength light source 7 is connected to the input terminal of the first wavelength division multiplexer 8, and the second wavelength division multiplexer 10 decomposes a plurality of wavelengths respectively to connect the optical fiber 9 (F ₁ ～F _m ), discrete microstructures are made on the optical fiber (F ₁ ～F _m ), the output of each optical fiber F ₁ ～F _m is connected to the input port of the second wavelength division multiplexer 10, and the second The output port of the wavelength division multiplexer 10 is connected to the first spectrum scanner 11 , and the first spectrum scanner 11 is connected to the data acquisition and analysis unit 17 .

In the vertical direction: the output of the second multi-wavelength light source 12 is connected to the input end of the third wavelength division multiplexer 13, and the third wavelength division multiplexer 13 decomposes a plurality of wavelengths respectively and connects the optical fiber 14 (F ₁ to F _n ), discrete microstructures are made on the optical fiber 14 (F ₁ to F _n ), and the output of each optical fiber (F ₁ to F _n ) is connected to the input port of the fourth wavelength division multiplexer 15 , the output port of the fourth wavelength division multiplexer 15 is connected to the second spectrum scanner 16, and the second spectrum scanner 16 is connected to the data acquisition and analysis unit 17, and the specific optical path is shown in FIG. 2 . The light guide fibers in the horizontal and vertical directions are distributed in a grid pattern.

The sensing process steps are as follows:

Step 1, in the horizontal direction: the optical signals containing multiple wavelengths output by the first multi-wavelength light source 7 are separated by the first wavelength division multiplexer 8 and then respectively guided into each light guide fiber 9 (F ₁ ~F _m ), and the light guide The signals containing sensing information output by the fibers 9 (F ₁ ~F _m ) are output to the second wavelength division multiplexer 10, and the second wavelength division multiplexer 10 summarizes the sensing information of each optical fiber to the spectrum scanner 11; The optical signals containing multiple wavelengths output by the second multi-wavelength light source 12 are respectively introduced into each optical guide fiber 14 (F ₁ ~ F _n ) by the third wavelength division multiplexer 13, and the optical guide fiber 14 (F ₁ ～F _n ) output the signal containing sensing information to the fourth wavelength division multiplexer 15, and the fourth wavelength division multiplexer 15 summarizes the sensing information of each optical fiber to the second spectral scanner 16; finally , the first spectrum scanner 11 and the second spectrum scanner 16 simultaneously send signals to the data acquisition and analysis unit 17 for processing and analysis.

Step 2, the data acquisition and analysis unit 17 can judge the change of the refractive index around the optical fiber according to the intensity change of each wavelength signal on the one hand, and then determine the height of dendrite growth; on the other hand, judge the pressure and temperature according to the drift of the wavelength The change.

Step 3. Combining the measurement results of multiple optical fibers, and distinguishing the position of the signal point (pressure, temperature or dendrite) for each measurement signal, the working process inside the battery can be monitored in real time and in a distributed manner.

Example 3:

The system structure of this case includes a third multi-wavelength light source 18 , a first circulator 19 , a fifth wavelength division multiplexer 20 , a third optical fiber unit 21 , a third spectrum scanner 22 , and a data acquisition and analysis unit 23 . The third light guiding fiber unit includes m light guiding fibers arranged in parallel in the horizontal direction.

The specific implementation steps of this case for sensing are as follows:

The system optical path connection mode is as follows: the output of the third multi-wavelength light source 18 is connected to the a port of the first circulator 19, the b port of the circulator 19 is connected to the input end of the fifth wavelength division multiplexer 20, and the fifth wavelength division multiplexer 20 decompose multiple wavelengths respectively to connect to the optical fiber 21 (F ₁ ~F _m ), on which _a discrete microstructure is made, and the c port of the _circulator 19 is connected to the first The three spectral scanners 22, the third spectral scanner 22 are connected to the data acquisition and analysis unit 23, and the specific optical path is shown in FIG. 3 .

The sensing process steps are as follows:

Step 1, the optical signal containing multiple wavelengths output by the third multi-wavelength light source 18 is sent to the a port of the circulator 19, and the signal is decomposed by the fifth wavelength division multiplexer 20 through the b port of the circulator 19 and then introduced into each guide respectively Optical fibers 21 (F ₁ ～F _m ), the back reflection/scattering signals inside each optical fiber (F ₁ ～F _m ) are output to the spectrum scanner 22 through ports b and c of the circulator 19, and finally, the spectrum scanning The instrument 22 sends the signal to the data acquisition and analysis unit 23 for processing and analysis;

Step 2, the data acquisition and analysis unit 23 can judge the change of the refractive index around the optical fiber according to the intensity change of each wavelength signal on the one hand, and then determine the height of dendrite growth; on the other hand, judge the pressure and temperature according to the drift of the wavelength The change.

Step 3. Using optical time domain reflectometry to integrate the measurement results of multiple optical fibers, and distinguish the position of the signal point (pressure, temperature or dendrite) for each measurement signal, the battery can be monitored in real time and in a distributed manner. internal working process.

Example 4:

The system structure of this embodiment includes a fourth multi-wavelength light source 24, a second circulator 25, a sixth wavelength division multiplexer 26, a fourth optical fiber unit 27, a fourth spectrum scanner 28, and a fifth multi-wavelength light source 29 , a third circulator 30 , a seventh wavelength division multiplexer 31 , a fifth optical fiber unit 32 , a fifth spectrum scanner 33 , and a data acquisition and analysis unit 34 . The fourth optical fiber unit 27 includes m optical fibers arranged in parallel in the horizontal direction, and the fifth optical fiber unit 32 includes n optical fibers arranged in parallel in the vertical direction.

The specific implementation steps of this case for sensing are as follows:

The system optical path connection mode is as follows: the output of the fourth multi-wavelength light source 24 is connected to the a port of the second circulator 25, the b port of the second circulator 25 is connected to the input end of the sixth wavelength division multiplexer 26, and the sixth wavelength division multiplexer Use the device 26 to decompose multiple wavelengths respectively to connect to the optical fiber 27 (F ₁ ~F _m ), on which the optical fiber 27 (F ₁ ~F _m ) is made with discrete microstructures, the second circulator 25 The c port is connected to the fourth spectral scanner 28; the output of the fifth multi-wavelength light source 29 is connected to the a port of the circulator 30, the b port of the third circulator 30 is connected to the input end of the wavelength division multiplexer 31, and the seventh wavelength division multiplexer The multiple wavelengths are decomposed by the device 31 to connect to the optical fiber 32 (F ₁ ˜F _n ), and discrete microstructures are made on the optical fiber 32 (F ₁ ˜F _n ). The third circulator 30 The c port is connected to the fifth spectrum scanner 33; the fourth spectrum scanner 28 and the fifth spectrum scanner 33 are connected to the data acquisition and analysis unit 34 at the same time, and the specific optical path is shown in FIG. 4 . The light guide fibers in the horizontal and vertical directions are distributed in a grid pattern.

The sensing process steps are as follows:

Step 1. The optical signal containing multiple wavelengths output by the fourth multi-wavelength light source 24 is sent to the a port of the second circulator 25, and the signal is decomposed by the sixth wavelength division multiplexer 26 through the b port of the second circulator 25 Import each optical fiber 27 respectively, and the back reflection/scattering signal inside each optical fiber is output to the fourth spectral scanner 28 through the b, c ports of the second circulator 25; The optical signals of two wavelengths are sent to the a port of the circulator 30, and the signal is decomposed by the seventh wavelength division multiplexer 31 through the b port of the third circulator 30, and then respectively introduced into each optical fiber 32 (F ₁ ~ F _n ), The back reflection/scattering signals inside each optical fiber 32 (F ₁ ~ F _n ) are output to the fifth spectral scanner 33 through the b and c ports of the third circulator 30; finally, the fourth spectral scanner 28 and the fourth spectral scanner The five spectral scanners 33 simultaneously send signals to the data acquisition and analysis unit 34 for processing and analysis;

Step 2, the data acquisition and analysis unit 34 can judge the change of the refractive index around the optical fiber according to the intensity change of each wavelength signal on the one hand, and then determine the height of the dendrite growth; on the other hand, judge the pressure and temperature according to the drift of the wavelength The change.

Step 3. Using optical time domain reflectometry to integrate the measurement results of multiple optical fibers, and distinguish the position of the signal point (pressure, temperature or dendrite) for each measurement signal, the battery can be monitored in real time and in a distributed manner. internal working process.

Claims (7)

1. A battery monitoring system, characterized by: the optical fiber detection device comprises a multi-wavelength light source, a wavelength division multiplexer, a light guide fiber unit and a spectrum scanner, wherein the multi-wavelength light source is used for providing a multi-wavelength detection optical signal, and the spectrum scanner is used for receiving and processing a response optical signal output by the light guide fiber; the multi-wavelength detection optical signal is injected into the light guide fiber unit through the wavelength division multiplexer, the light guide fiber is implanted into a single battery, and the response optical signal output by the light guide fiber is processed through the spectrum scanner; the light guide fiber unit comprises a plurality of light guide fibers which are distributed in parallel or in a cross way, and the light guide fibers are embedded into the battery diaphragm; the light guide fiber is provided with a microstructure.

2. The battery monitoring system of claim 1, wherein: the light guide fiber unit comprises a plurality of light guide fibers arranged in parallel or in a crossed mode, and the wavelength division multiplexer comprises a first wavelength division multiplexer and a second wavelength division multiplexer; the output end of the multi-wavelength light source is connected with the input end of the first wavelength division multiplexer, the output end of the first wavelength division multiplexer is connected with one end of the light guide fiber, the other end of the light guide fiber is connected with the input end of the second wavelength division multiplexer, and the output end of the second wavelength division multiplexer is connected with the input end of the spectrum scanner.

3. The battery monitoring system of claim 1, wherein: the optical fiber unit comprises a plurality of optical fibers arranged in parallel or in a crossed mode, the output end of the multi-wavelength light source is connected with the port a of the circulator, the port b of the circulator is connected with the wavelength division multiplexer, the other end of the wavelength division multiplexer is connected with the optical fibers, and the port c of the circulator is connected with the spectrum scanner.

4. The battery monitoring system of claim 1, wherein: the light guide fiber unit comprises light guide fibers, and the diameters of the light guide fibers are smaller than 125 mu m.

5. The battery monitoring system of claim 4, wherein: the surface of the light guide fiber is covered with an anticorrosive layer.

6. A battery monitoring method using the battery monitoring system according to claim 1, characterized in that: the battery monitoring method comprises the following steps:

(1) Embedding the light guide fiber into the diaphragm, and outputting a signal to the spectrum scanner by the light guide fiber;

(2) The spectrum scanner processes each received response optical signal and respectively analyzes event information carried by each wavelength signal;

(3) And comparing and analyzing the response optical signals of the plurality of optical fibers to determine the occurrence position of each event and the size of the area covered by the event.

7. The battery monitoring method according to claim 6, wherein: obtaining the change of the refractive index around the light guide fiber according to the intensity change of each wavelength response optical signal, and determining the growth thickness of the dendrite; the variation of pressure and temperature is obtained according to the drift amount of the wavelength.

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