Early warning system and method for falling of insulating coating of polar plate of alkaline water electrolysis tank

Abstract

The invention discloses an early warning system and method for falling of an insulating coating of a polar plate of an alkaline water electrolysis tank. The early warning system comprises a flexible latticed piezoresistor film pre-embedded in an insulating coating on the outer edge surface of a polar plate, an optical fiber sensor pre-embedded in the insulating coating on the outer edge surface of the polar plate, a resistance value data acquisition module, an optical signal data acquisition module, optical signal data of the optical fiber sensor and a monitoring and early warning system comprising an analysis and alarm module. The monitoring and early warning system analyzes and judges whether the coating falls off or not according to the resistance value data and the optical signal data, and sends out an alarm signal when the coating falls off; the flexible latticed piezoresistor film is connected with the resistance value data acquisition module through a resistance data outgoing line, the optical fiber sensor is connected with the optical signal data acquisition module through an optical signal data outgoing line, and the resistance value data acquisition module and the optical signal data acquisition module are respectively connected with the monitoring and early warning system. According to the invention, online real-time monitoring and active early warning of the insulating coating state of the electrolytic cell polar plate are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of alkaline water electrolyzers, and in particular to an early warning system and method for the shedding of insulating coatings on polar plates of alkaline water electrolyzers. Background Art

[0002] The alkaline water hydrogen electrolyzer is the core equipment for producing hydrogen through water electrolysis. It uses alkaline water as a raw material and produces hydrogen through electrolysis. The plates of the alkaline water electrolyzer are the charged components of the cell and consist of a pole frame and a main plate connected to the frame. The outer edge of the plate, located on the periphery of the pole frame (for circular plates, this is called the outer plate circle), is coated with an epoxy resin coating for insulation and safety.

[0003] However, the existing alkaline water hydrogen production electrolyzer still has the following problems: First, the plates on existing alkaline water electrolyzers are exposed to high current density, highly corrosive electrolytes, high temperature and high humidity environments for a long time, which can easily cause the insulating coating on the outer edge of the plates to break or fall off. Once the coating breaks or falls off, due to the small spacing between the plates (usually only 2 to 3 mm), the damage or shedding of the coating will expose the metal substrate at the outer edge of the plate, which may cause metal impurities (such as detached welding slag) to accidentally fall and cause a short circuit between the outer edges of adjacent plates. On the one hand, this leads to a decrease in electrolysis efficiency, short-circuit current diversion, a reduction in effective electrolysis current, and a 10% to 30% increase in energy consumption. On the other hand, it can also lead to safety issues such as fire and overheating caused by short circuits.

[0004] Secondly, the insulating coating on the outer surface of the plate has uneven coating thickness (usually 50~200 μm), which makes the weak areas of the coating more likely to peel off under thermal stress, further increasing the possibility of coating peeling or damage, posing a safety hazard.

[0005] Third, the insulating coating on the outer edge surface of the plate in the existing technology lacks an efficient coating shedding monitoring mechanism and usually relies on regular shutdown inspections (such as high-voltage withstand voltage tests). The maintenance cost is high, and traditional manual inspections are difficult to detect micron-level coating damage, and fault response is delayed.

[0006] Therefore, it is necessary to develop an early warning system and method for the peeling of the insulating coating of the alkaline water electrolyzer plate to solve the above problems. Summary of the Invention

[0007] To address the above issues, the present invention proposes an early warning system and method for the delamination of the insulating coating on the plates of alkaline water electrolyzers. This system aims to overcome the above-mentioned shortcomings of the prior art and achieve online real-time monitoring and active early warning of the insulating coating status of the plates of alkaline water electrolyzers. The specific technical solution is as follows: An early warning system for the shedding of insulating coating on the plates of an alkaline water electrolyzer, comprising: A flexible grid-like varistor film embedded in the insulating coating on the outer edge of the plate is used to monitor coating shedding. An optical fiber sensor embedded in the insulating coating on the outer surface of the electrode plate is used to monitor stress changes in the insulating coating; A resistance data acquisition module, configured to acquire resistance data of the flexible grid-shaped varistor film; An optical signal data acquisition module, configured to send, acquire, recover and process the optical signal data transmitted by the optical fiber sensor; A monitoring and early warning system including an analysis and alarm module for collecting and processing the resistance value data and the light signal data, analyzing and judging whether the coating has fallen off based on the resistance value data and the light signal data, and issuing an alarm signal when the coating has fallen off; Among them, the flexible grid-shaped varistor film is connected to the resistance value data acquisition module through a resistance data lead line, and the optical fiber sensor is connected to the optical signal data acquisition module through an optical signal data lead line. The resistance value data acquisition module and the optical signal data acquisition module are respectively connected to the monitoring and early warning system.

[0008] When the coating falls off, the stress generated by the coating falling off will act on the flexible grid-shaped varistor film, causing the resistance value of the flexible grid-shaped varistor film to change; therefore, when the resistance value change of the flexible grid-shaped varistor film exceeds the set threshold, the monitoring and early warning system determines that the coating may have fallen off.

[0009] In addition, when the coating falls off, the stress generated by the coating falling off will also act on the optical fiber of the optical fiber sensor, causing the local strain of the optical fiber of the optical fiber sensor to increase. The optical fiber sensor can detect the changes in these strains. The monitoring and early warning system can accurately locate the location of coating shedding based on the optical signal data and optical signal change data measured by the optical fiber sensor.

[0010] In the present invention, the insulating coating of the alkaline water electrolyzer plate is a composite coating, which includes a base transition layer, an intermediate layer and a surface layer in sequence. The flexible grid-shaped varistor film and the optical fiber sensor are pre-buried between the intermediate layer and the surface layer, respectively, and the coating of the coating adjacent to the flexible grid-shaped varistor film penetrates and fills the grid space of the flexible grid-shaped varistor film.

[0011] Preferably, the base transition layer uses a conductive microporous nickel layer with a thickness of 20~50 μm, which is formed by electroplating to enhance the adhesion of the coating, and its bonding force is ≥15 MPa; the intermediate layer uses an epoxy resin-silicon carbide composite coating with a thickness of 150~300 μm and a silicon carbide content of 10%~20% to provide insulation, wear resistance and alkali resistance, and its pH is greater than 14; the surface layer uses an insulating polyaniline PANI coating with a thickness of 20~50 μm.

[0012] In the present invention, the outer edge surface of the electrode plate of the alkaline water electrolyzer is divided into N monitoring areas along the circumferential direction. The number of the flexible grid-shaped varistor films is N, and the N flexible grid-shaped varistor films are correspondingly pre-buried in the insulating coating of the N monitoring areas, thereby forming a zoned monitoring of the shedding of the insulating coating of the electrode plate of the alkaline water electrolyzer.

[0013] When the change in resistance of the flexible grid-shaped varistor film exceeds a set threshold, the monitoring and early warning system issues a warning signal of coating peeling. The monitoring and early warning system also reports the specific area information of the coating peeling site around the outer edge of the plate based on the partition position of the flexible grid-shaped varistor film where the resistance has changed, making it convenient for maintenance personnel to carry out coating repairs in a timely and targeted manner.

[0014] Preferably, the flexible mesh-shaped varistor film is made of a conductive polymer material and is screen-printed to form a grid structure with a line width of 0.1 mm and a pitch of no more than 5 mm. Each grid unit is a pressure-sensitive unit. When the coating peels off, stress is generated that acts on the flexible mesh-shaped varistor film, changing the conductive flux within the flexible mesh-shaped varistor film, thereby causing a sudden change in the resistance of the flexible mesh-shaped varistor film.

[0015] Preferably, the optical fiber sensor adopts a multi-axis fiber grating sensor with multi-directional sensing capability or an OFDR optical fiber sensor with higher optical signal change positioning accuracy; the optical fiber of the optical fiber sensor is arranged in a serpentine-like manner along the circumference of the electrode plate in the coating of the alkaline water electrolyzer electrode plate, and the optical fiber of the optical fiber sensor arranged in a serpentine-like manner is interspersed and woven on the grid space of the flexible grid-like varistor film along the serpentine-like path.

[0016] The above-mentioned serpentine winding arrangement of the optical fiber of the optical fiber sensor, on the one hand, increases and expands the monitoring density and monitoring range of the optical fiber sensor on the electrode coating; on the other hand, since the optical fiber of the optical fiber sensor arranged in a serpentine winding manner is interspersed and woven on the grid space of the flexible grid-like piezoresistive film, the flexible grid-like piezoresistive film and the optical fiber sensor can simultaneously monitor the coating shedding situation in the same part, thereby increasing the accuracy of coating shedding monitoring.

[0017] In the present invention, the resistance value data acquisition module includes an ADC analog / digital converter, a voltage divider circuit and a multiplexer. The flexible grid-shaped piezoresistive film located in each partition on each electrode plate is connected to the ADC analog / digital converter through the multiplexer, and the ADC analog / digital converter is connected to a monitoring and early warning system. When the optical fiber sensor adopts an OFDR optical fiber sensor, the optical signal data acquisition module includes an OFDR optical fiber demodulator, the optical fiber of the optical fiber sensor is connected to the OFDR optical fiber demodulator, and the OFDR optical fiber demodulator is connected to the monitoring and early warning system.

[0018] Among them, the OFDR demodulator is used to obtain the strain distribution along the optical fiber; the multiplexer is used to select the flexible grid-shaped piezoresistive film in different partitions; and the ADC analog / digital converter is used to convert the resistance value of the flexible grid-shaped piezoresistive film into a digital signal for processing by the monitoring and early warning system (host computer).

[0019] The use of a multiplexer in the resistance value data acquisition module can reduce the number of wires required from multiple flexible grid-shaped varistor film partitions to the monitoring device, simplify wiring complexity, and reduce system costs.

[0020] As a further improvement, an alkaline water electrolyzer plate insulation coating peeling warning system of the present invention is also provided with a coating peeling detection enhancement module, which includes microcapsules dispersed in the surface coating, and the microcapsules are at least one of microcapsules containing conductive nanomaterials, microcapsules containing fluorescent nanomaterials, and microcapsules containing magnetic nanomaterials; when the coating is locally peeled off or cracked, the microcapsules rupture to release the nanomaterials, and penetrate into the flexible grid-like varistor film or attach to the optical fiber of the optical fiber sensor, thereby causing a sudden change in the resistance of the flexible grid-like varistor film, or changing the medium properties around the optical fiber of the optical fiber sensor, resulting in a sudden change in the optical signal of the optical fiber sensor; through the sudden change in the resistance of the flexible grid-like varistor film and the sudden change in the optical signal of the optical fiber sensor, the sensitivity and reliability of coating peeling monitoring are enhanced.

[0021] Preferably, the microcapsules are not only dispersed in the surface coating layer, but also dispersed in the middle coating layer.

[0022] The microcapsules in the present invention adopt a double-layer or multi-layer structure design, the outer layer is a protective layer to ensure that it will not break and release under normal conditions; the inner layer contains nanomaterials with specific functions.

[0023] Preferably, the microcapsules have a size range of 5 to 50 μm and are uniformly dispersed in the coating. The rupture threshold is designed to be slightly lower than the peel strength of the coating to ensure activation at the slight damage stage.

[0024] Preferably, the conductive nanomaterial in the microcapsule can be silver nanoparticles, copper nanoparticles or carbon nanotubes, which have extremely high conductivity and can penetrate into the varistor grid after the microcapsule ruptures, which can significantly improve the local conductivity and response speed, thereby enhancing the overall sensitivity of the flexible grid-like varistor film; the conductive nanomaterial can also be polyaniline nanoparticles or polypyrrole nanoparticles, which not only have good conductive properties but also have certain flexibility. They can form new conductive paths while filling cracks, thereby enhancing the overall sensitivity of the flexible grid-like varistor film.

[0025] Preferably, the conductive nanomaterial in the microcapsules is a wet conductive nanomaterial carrying a conductive liquid (e.g., conductive ionized water) to further extend its conductivity. When the coating is shed, the wet conductive nanomaterial is released, and the wet properties of the conductive nanomaterial are utilized to expand the conductive area, further improving conductivity.

[0026] Preferably, the conductive nanomaterial in the microcapsule can be replaced with a conductive liquid to prepare a microcapsule containing a conductive liquid, which has good conductive extensibility and low cost.

[0027] Preferably, the fluorescent nanomaterial in the microcapsule is quantum dots (QDs): as fluorescent markers, when the microcapsule ruptures, the quantum dots are released and come into contact with the optical fiber surface. By absorbing and re-emitting light, they can change the refractive index of the medium surrounding the optical fiber, thereby affecting the OFDR signal, thereby enhancing the sensitivity and reliability of coating shedding monitoring.

[0028] Preferably, the magnetic nanomaterial in the microcapsule can be Fe3O4 nanoparticles, which can not only indirectly affect the strain sensing ability of the optical fiber by changing the magnetic field distribution around the optical fiber, but also affect its optical properties by changing the dielectric constant around the optical fiber, thereby enhancing the sensitivity and reliability of coating shedding monitoring.

[0029] When the coating falls off and the microcapsules containing conductive nanomaterials rupture, the released conductive nanomaterials penetrate into the flexible mesh varistor film, thereby increasing the conductive path of the flexible mesh varistor film, causing the resistance of the flexible mesh varistor film to drop significantly. The monitoring and early warning system is used to determine the partition where the resistance of the flexible mesh varistor film has dropped significantly, and this partition is where the coating has fallen off.

[0030] When the coating falls off and the microcapsules containing fluorescent nanomaterials rupture, the released nanofluorescent materials (quantum dots) will produce a strong fluorescence signal under a lower excitation light intensity, directly changing the refractive index of the medium surrounding the optical fiber of the optical fiber sensor, thereby significantly reducing the intensity of the received optical fiber sensing signal. The specific location of the coating shedding can be identified and located through the monitoring and early warning system.

[0031] When the coating falls off and the microcapsules containing magnetic nanomaterials rupture, the released magnetic nanomaterials are exposed on the surface of the optical fiber, thereby changing the magnetic properties of the medium surrounding the optical fiber. The change in refractive index caused by the change in magnetic field leads to more light leakage or scattering, which significantly reduces the intensity of the backscattered light received by the OFDR system. The specific location of the coating shedding can be identified and located through the monitoring and early warning system.

[0032] Preferably, the nanomaterial contained in the microcapsule has a size of 5 to 50 μm and is uniformly dispersed in the coating. The rupture threshold of the microcapsule is lower than the peeling strength of the coating.

[0033] The various microcapsules in the present invention can be used alone or in combination according to actual needs to achieve synergistic enhancement of the flexible grid-shaped piezoresistive film and optical fiber sensing signal monitoring, thereby improving the performance of the entire monitoring and early warning system.

[0034] Preferably, the alkaline water electrolyzer is further provided with a temperature sensor for detecting the surface temperature of the electrode coating, and the temperature sensor is connected to a monitoring and early warning system to compensate for the measurement error of the resistance of the flexible grid-shaped varistor film caused by temperature changes.

[0035] A method for warning the loss of insulating coating on the plates of an alkaline water electrolyzer comprises pre-embedding a flexible grid-shaped varistor film in the insulating coating on the outer surface of the plate, and online monitoring the resistance of the flexible grid-shaped varistor film via a monitoring and warning system. Simultaneously, a fiber optic sensor is pre-embedded in the insulating coating on the outer surface of the plate, and online monitoring of the optical signal received by the fiber optic sensor and information on changes in the optical signal is performed via the monitoring and warning system. The monitoring and warning system employs multi-signal fusion analysis to synchronously monitor the resistance of the flexible grid-shaped varistor film, the optical signal received by the fiber optic sensor, and information on changes in the optical signal. When both the change in the resistance of the flexible grid-shaped varistor film and the change in the optical signal received by the fiber optic sensor exceed a set threshold, the monitoring and warning system issues a warning signal indicating coating loss. The monitoring and warning system also locates the zone on the outer edge of the plate where the coating has fallen off based on the circumferential position of the flexible grid-shaped varistor film with a resistance exceeding the threshold. Furthermore, the monitoring and warning system locates the specific location of the coating loss based on the optical signal and information on changes in the optical signal acquired by the fiber optic sensor.

[0036] As a further improvement, the present invention provides an early warning method for the shedding of the insulating coating of the plate of an alkaline water electrolyzer, further comprising uniformly distributing microcapsules containing conductive nanomaterials in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the flexible grid-shaped varistor to resistance changes, and uniformly distributing microcapsules containing fluorescent nanomaterials or microcapsules containing magnetic nanomaterials in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the optical signal received by the optical fiber sensor to changes; when the coating is shed, the microcapsules containing the conductive nanomaterials rupture and release the conductive nanomaterials that penetrate into the flexible grid-shaped varistor film, thereby increasing the conductive path of the flexible grid-shaped varistor film and causing the resistance of the flexible grid-shaped varistor film to drop significantly, thereby enhancing the sensitivity and reliability of the monitoring and early warning system for detecting coating shedding; when the coating is shed, the microcapsules containing the fluorescent nanomaterials rupture and release the nanofluorescent materials. A strong fluorescence signal is generated at a lower excitation light intensity, which directly changes the refractive index of the medium surrounding the optical fiber of the optical fiber sensor, thereby significantly reducing the received optical fiber sensing signal intensity. The monitoring and early warning system monitors the optical signal data and optical signal change data measured by the optical fiber sensor, identifies and locates the location of coating shedding, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in detecting coating shedding. When the coating shedding, the microcapsules containing magnetic nanomaterials are ruptured and the magnetic nanomaterials released are exposed to the surface of the optical fiber, thereby changing the magnetic properties of the medium surrounding the optical fiber. The refractive index change caused by the magnetic field change leads to more light leakage or scattering, which significantly reduces the backscattered light intensity received by the OFDR system in the monitoring and early warning system, so that the location of coating shedding can be identified and accurately located by the OFDR system, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in detecting coating shedding.

[0037] Preferably, the monitoring and early warning system synchronously processes the resistance change of the flexible grid varistor film and the optical signal change of the optical fiber sensor caused by the sudden stress change of the coating shedding through multi-signal fusion analysis. If the resistance exceeds the specified threshold (such as the resistance drop rate > 90%) and the optical signal change exceeds the specified threshold, it is determined that the coating has fallen off; and a graded alarm function is realized. When the first-level alarm (single-point abnormality) occurs, the monitoring and early warning system prompts to check the specified location area; when the second-level alarm (multi-point abnormality) occurs, the alkaline water electrolyzer automatically reduces the load and the monitoring and early warning system triggers an audible and visual alarm.

[0038] The beneficial effects of the present invention are: First, the present invention provides an early warning system and method for the loss of insulating coating on the plates of an alkaline water electrolyzer. A flexible grid-shaped varistor film and an optical fiber sensor are integrated into the insulating coating on the outer edge of the plate. By utilizing the change in the electrical characteristics (resistance) of the flexible grid-shaped varistor film when the coating is lost, and the change in the optical signal caused by the stress deformation of the optical fiber of the optical fiber sensor when the coating is lost, an online dual monitoring and early warning mechanism for coating loss events on the plate is realized, and the coating loss monitoring is reliable.

[0039] Secondly, the present invention provides an early warning system and method for the peeling of the insulating coating of the plate of an alkaline water electrolyzer. The flexible grid-shaped varistor film with an innovative structure has a large monitoring coverage area. The outer edge of the electrode plate is divided into zones, and a corresponding flexible grid-shaped varistor film is set in the coating of each electrode zone. On the one hand, the number of resistor lead wires is greatly reduced, and on the other hand, the specific zone position where the coating has fallen off can be located. The monitoring results of the optical fiber sensor are further combined to achieve precise positioning of the coating falling off position.

[0040] Third, the present invention provides an early warning system and method for the peeling of insulating coating on the plates of alkaline water electrolyzers, which is equipped with a coating peeling detection enhancement module. Through the microcapsule enhanced detection mechanism, it causes a sudden change in the resistance of the flexible grid-shaped varistor film and a sudden change in the optical signal of the optical fiber sensor when the coating peels off, thereby significantly enhancing the sensitivity and reliability of coating peeling monitoring.

[0041] Fourth, the present invention provides an early warning system and method for the loss of insulating coating on the plates of alkaline water electrolyzers. A base transition layer is provided on the metal substrate surface at the outer edge of the plate. The base transition layer uses a conductive microporous nickel layer with a thickness of 20 to 50 μm. This can increase the adhesion of the coating by 200%, extend the service life from 2 years to 5 years, and reduce short-circuit accidents by 95%.

[0042] Fifth, the present invention provides an early warning system and method for the peeling of insulating coating on the plates of an alkaline water electrolyzer, which can achieve high-precision, real-time online monitoring of the peeling status of the coating on the outer edge of the plates of the water electrolyzer. Through real-time online monitoring, the specific location of the coating peeling can be quickly and accurately located, facilitating the timely repair of the peeled coating, avoiding unplanned downtime, and reducing annual maintenance costs by 40%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the overall principle of an early warning system for the insulation coating shedding of an alkaline water electrolyzer plate of the present invention; Figure 2 It is a schematic diagram of the layered structure of the insulating coating of the plate of the alkaline water electrolyzer; Figure 3: Schematic diagram of the optical fiber sensor in the outer edge coating of the alkaline water electrolyzer plate being interwoven and woven into the grid space of the flexible grid-like piezoresistive film.

[0044] In the figure: 1. electrode plate, 2. base transition layer, 3. middle layer, 4. flexible grid-shaped varistor film, 5. surface layer, 6. optical fiber of the optical fiber sensor, 7. resistance data lead-out line, 8. optical signal data lead-out line. DETAILED DESCRIPTION

[0045] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] Example 1: like Figures 1 to 3 The present invention shows an embodiment of an early warning system for the insulation coating of an alkaline water electrolyzer plate, comprising: A flexible grid-shaped varistor film 4 embedded in the insulating coating on the outer edge of the plate 1 is used to monitor the shedding of the coating; An optical fiber sensor embedded in the insulating coating on the outer surface of the electrode plate 1 is used to monitor stress changes in the insulating coating; A resistance data acquisition module, configured to acquire resistance data of the flexible grid-shaped varistor film; An optical signal data acquisition module, configured to send, collect, recover and process the optical signal data transmitted by the optical fiber sensor; A monitoring and early warning system including an analysis and alarm module for collecting and processing the resistance value data and the light signal data, analyzing and judging whether the coating has fallen off based on the resistance value data and the light signal data, and issuing an alarm signal when the coating has fallen off; Among them, the flexible grid-shaped varistor film 4 is connected to the resistance value data acquisition module through the resistance data lead line 7, and the optical fiber sensor is connected to the optical signal data acquisition module through the optical signal data lead line 8. The resistance value data acquisition module and the optical signal data acquisition module are respectively connected to the monitoring and early warning system.

[0047] When the coating falls off, the stress generated by the coating falling off will act on the flexible grid-shaped varistor film 4, causing the resistance value of the flexible grid-shaped varistor film 4 to change; therefore, when the resistance value change of the flexible grid-shaped varistor film 4 exceeds the set threshold, the monitoring and early warning system determines that the coating may have fallen off.

[0048] In addition, when the coating falls off, the stress generated by the coating falling off will also act on the optical fiber 6 of the optical fiber sensor, causing the local strain of the optical fiber 6 of the optical fiber sensor to increase. The optical fiber sensor can detect the changes in these strains. The monitoring and early warning system can accurately locate the location of the coating falling off based on the optical signal data and optical signal change data measured by the optical fiber sensor.

[0049] In this embodiment, the insulating coating of the alkaline water electrolyzer plate is a composite coating, which includes a base transition layer 2, an intermediate layer 3 and a surface layer 4 in sequence. The flexible grid-shaped varistor film 4 and the optical fiber sensor are pre-buried between the intermediate layer 3 and the surface layer 5, respectively, and the coating of the coating adjacent to the flexible grid-shaped varistor film 4 penetrates and fills the grid space of the flexible grid-shaped varistor film 4.

[0050] Preferably, the base transition layer uses a conductive microporous nickel layer with a thickness of 20~50 μm, which is formed by electroplating to enhance the adhesion of the coating, and its bonding force is ≥15 MPa; the intermediate layer uses an epoxy resin-silicon carbide composite coating with a thickness of 150~300 μm and a silicon carbide content of 10%~20% to provide insulation, wear resistance and alkali resistance, and its pH is greater than 14; the surface layer uses an insulating polyaniline PANI coating with a thickness of 20~50 μm.

[0051] In this embodiment, the outer edge surface of the electrode plate of the alkaline water electrolyzer is divided into N monitoring areas along the circumferential direction. The number of the flexible grid-shaped varistor films is N, and the N flexible grid-shaped varistor films are pre-buried in the insulating coating of the N monitoring areas, thereby forming a zoned monitoring of the shedding of the insulating coating of the electrode plate of the alkaline water electrolyzer.

[0052] When the change in resistance of the flexible grid-shaped varistor film exceeds a set threshold, the monitoring and early warning system issues a warning signal of coating peeling. The monitoring and early warning system also reports the specific area information of the coating peeling site around the outer edge of the plate based on the partition position of the flexible grid-shaped varistor film where the resistance has changed, making it convenient for maintenance personnel to carry out coating repairs in a timely and targeted manner.

[0053] Preferably, the flexible mesh-shaped varistor film is made of a conductive polymer material and is screen-printed to form a grid structure with a line width of 0.1 mm and a pitch of no more than 5 mm. Each grid unit is a pressure-sensitive unit. When the coating peels off, stress is generated that acts on the flexible mesh-shaped varistor film, changing the conductive flux within the flexible mesh-shaped varistor film, thereby causing a sudden change in the resistance of the flexible mesh-shaped varistor film.

[0054] Preferably, the optical fiber sensor adopts a multi-axis fiber grating sensor with multi-directional sensing capability or an OFDR optical fiber sensor with higher optical signal change positioning accuracy; the optical fiber of the optical fiber sensor is arranged in a serpentine-like manner along the circumference of the electrode plate in the coating of the alkaline water electrolyzer electrode plate, and the optical fiber of the optical fiber sensor arranged in a serpentine-like manner is interspersed and woven on the grid space of the flexible grid-like varistor film along the serpentine-like path.

[0055] The above-mentioned serpentine winding arrangement of the optical fiber of the optical fiber sensor, on the one hand, increases and expands the monitoring density and monitoring range of the optical fiber sensor on the electrode coating; on the other hand, since the optical fiber of the optical fiber sensor arranged in a serpentine winding manner is interspersed and woven on the grid space of the flexible grid-like piezoresistive film, the flexible grid-like piezoresistive film and the optical fiber sensor can simultaneously monitor the coating shedding situation in the same part, thereby increasing the accuracy of coating shedding monitoring.

[0056] In this embodiment, the resistance value data acquisition module includes an ADC analog / digital converter, a voltage divider circuit and a multiplexer. The flexible grid-shaped piezoresistive film located in each partition on each electrode plate is connected to the ADC analog / digital converter through the multiplexer, and the ADC analog / digital converter is connected to the monitoring and early warning system; when the optical fiber sensor adopts an OFDR optical fiber sensor, the optical signal data acquisition module includes an OFDR optical fiber demodulator, the optical fiber of the optical fiber sensor is connected to the OFDR optical fiber demodulator, and the OFDR optical fiber demodulator is connected to the monitoring and early warning system.

[0057] Among them, the OFDR demodulator is used to obtain the strain distribution along the optical fiber; the multiplexer is used to select the flexible grid-shaped piezoresistive film in different partitions; and the ADC analog / digital converter is used to convert the resistance value of the flexible grid-shaped piezoresistive film into a digital signal for processing by the monitoring and early warning system (host computer).

[0058] The use of a multiplexer in the resistance value data acquisition module can reduce the number of wires required from multiple flexible grid-shaped varistor film partitions to the monitoring device, simplify wiring complexity, and reduce system costs.

[0059] As a further improvement, an alkaline water electrolyzer plate insulation coating peeling warning system of the present invention is also provided with a coating peeling detection enhancement module, which includes microcapsules dispersed in the surface coating, and the microcapsules are at least one of microcapsules containing conductive nanomaterials, microcapsules containing fluorescent nanomaterials, and microcapsules containing magnetic nanomaterials; when the coating is locally peeled off or cracked, the microcapsules rupture to release the nanomaterials, and penetrate into the flexible grid-like varistor film or attach to the optical fiber of the optical fiber sensor, thereby causing a sudden change in the resistance of the flexible grid-like varistor film, or changing the medium properties around the optical fiber of the optical fiber sensor, resulting in a sudden change in the optical signal of the optical fiber sensor; through the sudden change in the resistance of the flexible grid-like varistor film and the sudden change in the optical signal of the optical fiber sensor, the sensitivity and reliability of coating peeling monitoring are enhanced.

[0060] Preferably, the microcapsules are not only dispersed in the surface coating layer, but also dispersed in the middle coating layer.

[0061] The microcapsules in the present invention adopt a double-layer or multi-layer structure design, the outer layer is a protective layer to ensure that it will not break and release under normal conditions; the inner layer contains nanomaterials with specific functions.

[0062] Preferably, the microcapsules have a size range of 5 to 50 μm and are uniformly dispersed in the coating. The rupture threshold is designed to be slightly lower than the peel strength of the coating to ensure activation at the slight damage stage.

[0063] Preferably, the conductive nanomaterial in the microcapsule can be silver nanoparticles, copper nanoparticles or carbon nanotubes, which have extremely high conductivity and can penetrate into the varistor grid after the microcapsule ruptures, which can significantly improve the local conductivity and response speed, thereby enhancing the overall sensitivity of the flexible grid-like varistor film; the conductive nanomaterial can also be polyaniline nanoparticles or polypyrrole nanoparticles, which not only have good conductive properties but also have certain flexibility. They can form new conductive paths while filling cracks, thereby enhancing the overall sensitivity of the flexible grid-like varistor film.

[0064] Preferably, the conductive nanomaterial in the microcapsules is a wet conductive nanomaterial carrying a conductive liquid (e.g., conductive ionized water) to further extend its conductivity. When the coating is shed, the wet conductive nanomaterial is released, and the wet properties of the conductive nanomaterial are utilized to expand the conductive area, further improving conductivity.

[0065] Preferably, the conductive nanomaterial in the microcapsule can be replaced with a conductive liquid to prepare a microcapsule containing a conductive liquid, which has good conductive extensibility and low cost.

[0066] Preferably, the fluorescent nanomaterial in the microcapsule is quantum dots (QDs): as fluorescent markers, when the microcapsule ruptures, the quantum dots are released and come into contact with the optical fiber surface. By absorbing and re-emitting light, they can change the refractive index of the medium surrounding the optical fiber, thereby affecting the OFDR signal, thereby enhancing the sensitivity and reliability of coating shedding monitoring.

[0067] Preferably, the magnetic nanomaterial in the microcapsule can be Fe3O4 nanoparticles, which can not only indirectly affect the strain sensing ability of the optical fiber by changing the magnetic field distribution around the optical fiber, but also affect its optical properties by changing the dielectric constant around the optical fiber, thereby enhancing the sensitivity and reliability of coating shedding monitoring.

[0068] When the coating falls off and the microcapsules containing conductive nanomaterials rupture, the released conductive nanomaterials penetrate into the flexible mesh varistor film, thereby increasing the conductive path of the flexible mesh varistor film, causing the resistance of the flexible mesh varistor film to drop significantly. The monitoring and early warning system is used to determine the partition where the resistance of the flexible mesh varistor film has dropped significantly, and this partition is where the coating has fallen off.

[0069] When the coating falls off and the microcapsules containing fluorescent nanomaterials rupture, the released nanofluorescent materials (quantum dots) will produce a strong fluorescence signal under a lower excitation light intensity, directly changing the refractive index of the medium surrounding the optical fiber of the optical fiber sensor, thereby significantly reducing the intensity of the received optical fiber sensing signal. The specific location of the coating shedding can be identified and located through the monitoring and early warning system.

[0070] When the coating falls off and the microcapsules containing magnetic nanomaterials rupture, the released magnetic nanomaterials are exposed on the surface of the optical fiber, thereby changing the magnetic properties of the medium surrounding the optical fiber. The change in refractive index caused by the change in magnetic field leads to more light leakage or scattering, which significantly reduces the intensity of the backscattered light received by the OFDR system. The specific location of the coating shedding can be identified and located through the monitoring and early warning system.

[0071] Preferably, the nanomaterial contained in the microcapsule has a size of 5 to 50 μm and is uniformly dispersed in the coating. The rupture threshold of the microcapsule is lower than the peeling strength of the coating.

[0072] The various microcapsules in this embodiment can be used individually or in combination according to actual needs to achieve synergistic enhancement of the flexible grid-shaped piezoresistive film and optical fiber sensing signal monitoring, thereby improving the performance of the entire monitoring and early warning system.

[0073] Preferably, the alkaline water electrolyzer is further provided with a temperature sensor for detecting the surface temperature of the electrode coating, and the temperature sensor is connected to a monitoring and early warning system to compensate for the measurement error of the resistance of the flexible grid-shaped varistor film caused by temperature changes.

[0074] In this embodiment, the flexible grid-shaped varistor film can use PI film as the substrate with a thickness of 50 μm, and the pressure-sensitive material is a carbon black / silicone rubber composite. A grid with a line width of 0.1 mm and a spacing of no more than 5 mm is formed by screen printing; the lead-out pads are printed with silver paste and located on both sides of the edge of the film.

[0075] In this embodiment, the microcapsules containing conductive nanomaterials are prepared using silver nanoparticles (Ag NPs) with a particle size of approximately 20 nm. The preparation method uses an emulsion polymerization method to disperse the silver nanoparticles in an aqueous phase and use urea-formaldehyde resin as a protective layer to form microcapsules with an average particle size of 20 μm.

[0076] The microcapsules containing the conductive nanomaterials can be added to the intermediate layer coating and the surface layer coating before coating at a mass ratio of 3% to 5% and uniformly dispersed.

[0077] In this embodiment, the microcapsules containing magnetic nanomaterials are prepared using Fe3O4 nanoparticles with a particle size of about 10 nm. The preparation method adopts a chemical coprecipitation method to disperse the Fe3O4 nanoparticles in an aqueous phase and use silicon dioxide (SiO2) as a protective layer to form microcapsules with an average particle size of 20 μm.

[0078] The microcapsules containing the magnetic nanomaterials can be added to the intermediate layer coating and the surface layer coating before coating at a mass ratio of 3% to 5% and uniformly dispersed.

[0079] In this embodiment, the preparation of the microcapsules containing fluorescent nanomaterials uses CdSe / ZnS core-shell structure quantum dots (QDs) with an emission wavelength of 600 nm. The preparation method uses a solvent evaporation method to disperse the quantum dots in an organic solvent and use polyurethane as a protective layer to form microcapsules with an average particle size of 20 μm.

[0080] The microcapsules containing fluorescent nanomaterials can be added to the intermediate layer coating and the surface layer coating before coating at a mass ratio of 3% to 5% and uniformly dispersed.

[0081] Example 2: A method for warning the loss of insulating coating on the plates of an alkaline water electrolyzer comprises pre-embedding a flexible grid-shaped varistor film in the insulating coating on the outer surface of the plate, and online monitoring the resistance of the flexible grid-shaped varistor film via a monitoring and warning system. Simultaneously, a fiber optic sensor is pre-embedded in the insulating coating on the outer surface of the plate, and online monitoring of the optical signal received by the fiber optic sensor and information on changes in the optical signal is performed via the monitoring and warning system. The monitoring and warning system employs multi-signal fusion analysis to synchronously monitor the resistance of the flexible grid-shaped varistor film, the optical signal received by the fiber optic sensor, and information on changes in the optical signal. When both the change in the resistance of the flexible grid-shaped varistor film and the change in the optical signal received by the fiber optic sensor exceed a set threshold, the monitoring and warning system issues a warning signal indicating coating loss. The monitoring and warning system also locates the zone on the outer edge of the plate where the coating has fallen off based on the circumferential position of the flexible grid-shaped varistor film with a resistance exceeding the threshold. Furthermore, the monitoring and warning system locates the specific location of the coating loss based on the optical signal and information on changes in the optical signal acquired by the fiber optic sensor.

[0082] As a further improvement, the present invention provides an early warning method for the shedding of the insulating coating of the plate of an alkaline water electrolyzer, further comprising uniformly distributing microcapsules containing conductive nanomaterials in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the flexible grid-shaped varistor to resistance changes, and uniformly distributing microcapsules containing fluorescent nanomaterials or microcapsules containing magnetic nanomaterials in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the optical signal received by the optical fiber sensor to changes; when the coating is shed, the microcapsules containing the conductive nanomaterials rupture and release the conductive nanomaterials that penetrate into the flexible grid-shaped varistor film, thereby increasing the conductive path of the flexible grid-shaped varistor film and causing the resistance of the flexible grid-shaped varistor film to drop significantly, thereby enhancing the sensitivity and reliability of the monitoring and early warning system for detecting coating shedding; when the coating is shed, the microcapsules containing the fluorescent nanomaterials rupture and release the nanofluorescent materials. A strong fluorescence signal is generated at a lower excitation light intensity, which directly changes the refractive index of the medium surrounding the optical fiber of the optical fiber sensor, thereby significantly reducing the received optical fiber sensing signal intensity. The monitoring and early warning system monitors the optical signal data and optical signal change data measured by the optical fiber sensor, identifies and locates the location of coating shedding, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in detecting coating shedding. When the coating shedding, the microcapsules containing magnetic nanomaterials are ruptured and the magnetic nanomaterials released are exposed to the surface of the optical fiber, thereby changing the magnetic properties of the medium surrounding the optical fiber. The refractive index change caused by the magnetic field change leads to more light leakage or scattering, which significantly reduces the backscattered light intensity received by the OFDR system in the monitoring and early warning system, so that the location of coating shedding can be identified and accurately located by the OFDR system, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in detecting coating shedding.

[0083] Preferably, the monitoring and early warning system synchronously processes the resistance change of the flexible grid varistor film and the optical signal change of the optical fiber sensor caused by the sudden stress change of the coating shedding through multi-signal fusion analysis. If the resistance exceeds the specified threshold (such as the resistance drop rate > 90%) and the optical signal change exceeds the specified threshold, it is determined that the coating has fallen off; and a graded alarm function is realized. When the first-level alarm (single-point abnormality) occurs, the monitoring and early warning system prompts to check the specified location area; when the second-level alarm (multi-point abnormality) occurs, the alkaline water electrolyzer automatically reduces the load and the monitoring and early warning system triggers an audible and visual alarm.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An early warning system for the peeling of the insulating coating of the plate of an alkaline water electrolyzer, characterized in that: include: A flexible grid-like varistor film embedded in the insulating coating on the outer edge of the plate is used to monitor coating shedding. An optical fiber sensor embedded in the insulating coating on the outer surface of the electrode plate is used to monitor stress changes in the insulating coating; A resistance data acquisition module, configured to acquire resistance data of the flexible grid-shaped varistor film; An optical signal data acquisition module, configured to send, collect, recover and process the optical signal data transmitted by the optical fiber sensor; A monitoring and early warning system including an analysis and alarm module for collecting and processing the resistance value data and the light signal data, analyzing and judging whether the coating has fallen off based on the resistance value data and the light signal data, and issuing an alarm signal when the coating has fallen off; Among them, the flexible grid-shaped varistor film is connected to the resistance value data acquisition module through a resistance data lead line, and the optical fiber sensor is connected to the optical signal data acquisition module through an optical signal data lead line. The resistance value data acquisition module and the optical signal data acquisition module are respectively connected to the monitoring and early warning system.

2. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 1, characterized in that: The insulating coating of the alkaline water electrolyzer plate is a composite coating, which includes a base transition layer, an intermediate layer and a surface layer in sequence. The flexible grid-shaped varistor film and the optical fiber sensor are pre-buried between the intermediate layer and the surface layer, respectively, and the coating of the coating adjacent to the flexible grid-shaped varistor film penetrates and fills the grid space of the flexible grid-shaped varistor film.

3. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 2, characterized in that: The base transition layer uses a conductive microporous nickel layer with a thickness of 20~50 μm, which is formed by electroplating to enhance the adhesion of the coating, and its bonding force is ≥15 MPa; the intermediate layer uses an epoxy resin-silicon carbide composite coating with a thickness of 150~300 μm and a silicon carbide content of 10%~20% to provide insulation, wear resistance and alkali resistance, and its pH is greater than 14; the surface layer uses an insulating polyaniline PANI coating with a thickness of 20~50 μm.

4. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 1, characterized in that: The outer edge surface of the electrode plate of the alkaline water electrolyzer is divided into N monitoring areas along the circumferential direction. The number of the flexible grid-shaped varistor films is N, and the N flexible grid-shaped varistor films are pre-buried in the insulating coating of the N monitoring areas, thereby forming a zoned monitoring of the shedding of the insulating coating of the electrode plate of the alkaline water electrolyzer.

5. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 1, characterized in that: The flexible grid-shaped varistor film is made of a conductive polymer material and is formed into a grid structure with a line width of 0.1 mm and a spacing of no more than 5 mm through a screen printing process. Each grid unit is a pressure-sensitive unit. When the coating falls off, the resistance of the flexible grid-shaped varistor film changes suddenly.

6. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 4, characterized in that: The optical fiber sensor adopts a multi-axis fiber grating sensor with multi-directional sensing capability or an OFDR optical fiber sensor with higher optical signal change positioning accuracy; the optical fiber of the optical fiber sensor is arranged in a serpentine-like manner along the circumference of the electrode plate in the coating of the alkaline water electrolyzer electrode plate, and the optical fiber of the optical fiber sensor arranged in a serpentine-like manner is interspersed and woven on the grid space of the flexible grid-like piezoresistive film along the serpentine-like path.

7. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 6, characterized in that: The resistance value data acquisition module includes an ADC analog / digital converter, a voltage divider circuit and a multiplexer. The flexible grid-shaped piezoresistive film located in each partition of each electrode plate is connected to the ADC analog / digital converter through the multiplexer, and the ADC analog / digital converter is connected to the monitoring and early warning system. When the optical fiber sensor adopts an OFDR optical fiber sensor, the optical signal data acquisition module includes an OFDR optical fiber demodulator, the optical fiber of the optical fiber sensor is connected to the OFDR optical fiber demodulator, and the OFDR optical fiber demodulator is connected to the monitoring and early warning system.

8. The early warning system for the insulation coating peeling off of the plate of an alkaline water electrolyzer according to claim 1, characterized in that: A coating shedding detection enhancement module is also provided, which includes microcapsules dispersed in the surface coating, and the microcapsules are at least one of microcapsules containing conductive nanomaterials, microcapsules containing fluorescent nanomaterials, and microcapsules containing magnetic nanomaterials. When the coating partially peels off or cracks, the microcapsules rupture to release the nanomaterials, and penetrate into the flexible grid-shaped piezoresistive film or adhere to the optical fiber of the optical fiber sensor, thereby causing a sudden change in the resistance of the flexible grid-shaped piezoresistive film, or changing the medium properties around the optical fiber of the optical fiber sensor, resulting in a sudden change in the optical signal of the optical fiber sensor. The sensitivity and reliability of coating shedding monitoring are enhanced by the sudden change in the resistance of the flexible grid-shaped piezoresistive film and the sudden change in the optical signal of the optical fiber sensor.

9. A method for early warning of the peeling of the insulating coating of the plate of an alkaline water electrolyzer, characterized in that: The method includes pre-embedding a flexible grid-shaped varistor film in the insulating coating on the outer surface of the electrode plate, and online monitoring of the resistance of the flexible grid-shaped varistor film through a monitoring and early warning system; at the same time, pre-embedding an optical fiber sensor in the insulating coating on the outer surface of the electrode plate, and online monitoring of the optical signal received by the optical fiber sensor and the optical signal change information through the monitoring and early warning system; the monitoring and early warning system adopts multi-signal fusion analysis to synchronously monitor the resistance of the flexible grid-shaped varistor film and the optical signal received by the optical fiber sensor and the optical signal change information; when the resistance change value of the flexible grid-shaped varistor film and the optical signal change value received by the optical fiber sensor simultaneously exceed the set threshold value, the monitoring and early warning system issues a coating shedding warning signal; the monitoring and early warning system also locates the partition where the coating has shedding on the outer edge of the electrode plate based on the partition position of the flexible grid-shaped varistor film whose resistance exceeds the threshold value on the circumferential direction of the outer edge of the electrode plate; at the same time, the monitoring and early warning system also locates the specific location of the coating shedding based on the optical signal and optical signal change information obtained by the optical fiber sensor.

10. The method for early warning of plate insulation coating shedding of an alkaline water electrolyzer according to claim 1, characterized in that: The invention also includes microcapsules containing conductive nanomaterials uniformly distributed in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the flexible grid-shaped varistor to resistance changes, and microcapsules containing fluorescent nanomaterials or microcapsules containing magnetic nanomaterials uniformly distributed in the insulating coating on the outer surface of the plate, which can enhance the sensitivity of the optical signal received by the optical fiber sensor. When the coating falls off, the microcapsules containing conductive nanomaterials are ruptured and the conductive nanomaterials released penetrate into the flexible grid-shaped varistor film, thereby increasing the conductive path of the flexible grid-shaped varistor film and causing the resistance of the flexible grid-shaped varistor film to drop significantly, thereby enhancing the sensitivity and reliability of the monitoring and early warning system for detecting coating shedding. When the coating falls off, the nano-fluorescent materials released by the rupture of the microcapsules containing fluorescent nanomaterials produce strong fluorescence under lower excitation light intensity. The optical signal directly changes the refractive index of the medium surrounding the optical fiber of the optical fiber sensor, thereby significantly reducing the received optical fiber sensing signal intensity. The monitoring and early warning system monitors the optical signal data and optical signal change data measured by the optical fiber sensor, identifies and locates the location of coating shedding, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in monitoring coating shedding. When the coating shedding, the microcapsules containing magnetic nanomaterials rupture and release magnetic nanomaterials that are exposed on the surface of the optical fiber, thereby changing the magnetic properties of the medium surrounding the optical fiber. The refractive index change caused by the magnetic field change leads to more light leakage or scattering, which significantly reduces the backscattered light intensity received by the OFDR system in the monitoring and early warning system, so that the location of coating shedding can be identified and accurately located by the OFDR system, thereby further enhancing the sensitivity and reliability of the monitoring and early warning system in monitoring coating shedding.

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