Method and device for online detection of alkali leakage of electrolytic cell gasket

Abstract

The invention discloses a method and device for on-line detection of alkali leakage of an electrolytic cell gasket. The device comprises a deformable detector carrier, and the detector carrier is attached to the outer circle surface of a polar plate through deformation profiling or arranged on the outer circle surface of the polar plate at a certain interval; a plurality of detection parts are integrated on the detector carrier, the plurality of detection parts form a space sensor array arranged around the electrolytic cell in a specific number mode on the periphery of the electrolytic cell, and the number of the detection parts corresponds to a position code of a preset monitoring point on the electrolytic cell model; data of each detection component is sampled at a specific frequency to form data chains, each data chain is analyzed in real time, and gradient mutation of the data chains is used as a leakage judgment basis. The method has the advantages of high response speed, high detection sensitivity and high positioning precision, and various key indexes comprehensively exceed those of a traditional method; in the aspect of economic benefits, the operation and maintenance cost is reduced, and accident loss is reduced; and the safety is high, passive coping is upgraded to active protection, and the safety risk caused by alkali liquor leakage is thoroughly solved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by alkaline water electrolysis, and in particular to a method and a device for online detection of alkali leakage of an electrolytic cell gasket. Background Art

[0002] The electrolyzer operates under high pressure, high temperature and strong alkaline environment. The sealing gasket between the end plate and the electrode plate is prone to aging or deformation due to long-term mechanical stress, chemical corrosion and thermal cycle, resulting in alkaline solution leakage. In the scenario of green electricity hydrogen production, the current density of the electrolyzer is increased to more than 10,000 A / m², the Joule heat increases significantly, the temperature gradient in the gasket area intensifies, and the risk of leakage is higher. The volatility of renewable energy (wind power, photovoltaic) causes the electrolyzer to start and stop frequently, and the gasket is subjected to periodic thermal stress, which accelerates aging and leakage. At present, manual inspections and video monitoring are generally adopted, which cannot detect early leaks in time.

[0003] Manual inspection and video surveillance have the following defects: Lag: Relying on manual inspection or offline detection, early leakage cannot be detected in real time; High false alarm rate: Single sensors (such as humidity sensors) are easily affected by the high humidity environment inside the electrolyzer; Difficult to locate: Leakage points are mostly located in the hidden gaps between the end pressure plates, which are difficult to accurately locate using conventional means.

[0004] In view of the above, it is necessary to provide a real-time, high-precision device and method for detecting alkali leakage from electrolytic cell gaskets, combining multi-parameter sensing with intelligent algorithms to achieve early warning of leakage, and linking safety measures such as shutdown and isolation to avoid equipment damage or safety accidents caused by the spread of alkali solution. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a method and device for online detection of alkali leakage in electrolytic cell gaskets.

[0006] To achieve the above object, the technical solution of the present invention is as follows: a method for online detection of alkali leakage of electrolytic cell gaskets, comprising a deformable detector carrier, wherein the detector carrier is arranged on the outer circumferential surface of the electrode plate by deforming and conforming or maintaining a certain distance; A number of detection components are integrated on the detector carrier. The detection components are specifically numbered and arranged around the electrolytic cell to form a spatial sensor array. The numbers of the detection components correspond to the position codes of the preset monitoring points on the electrolytic cell model. The data of each detection component is sampled at a specific frequency to form a data chain, and each data chain is analyzed in real time. The gradient mutation of the data chain is used as a basis for leakage judgment, and the data is located at the monitoring point on the electrolytic cell model.

[0007] Furthermore, the detection component includes a temperature detection sensor for monitoring the circumferential temperature change at a preset point; the temperature detection sensor is one or more of a grating temperature sensor, a thermistor, a flexible thin-film temperature sensor, a thermocouple, and an infrared temperature sensor.

[0008] Furthermore, a humidity detection sensor is used to monitor the circumferential humidity change at a preset point; the humidity detection sensor is one or more of a capacitive humidity sensor, a resistive humidity sensor, a flexible thin-film humidity sensor, and an optical fiber humidity sensor.

[0009] Furthermore, the detector carrier is a flexible circuit board, enabling the detector carrier to have degrees of freedom of deformation in the axial and / or radial directions of the electrolytic cell.

[0010] Furthermore, the detection component further includes a microchannel impedance sensor. A serpentine microchannel is etched on the side of the detector carrier facing the electrolytic cell. A solid-state flexible conductive composite material is formed in the microchannel, and a pH-responsive hydrogel layer is coated on the surface. The electrolyte at the leakage point passes through the hydrogel layer and enters the microchannel to change the impedance value.

[0011] Furthermore, the solid-state flexible conductive composite material is formed by uniformly embedding silver nanowires (AgNWs) as conductive fillers into a polydimethylsiloxane (PDMS) solid matrix. The PDMS precursor is infiltrated into the AgNWs network by vacuum-assisted filling, and an embedded structure is formed after curing. Then, the AgNWs and the PDMS prepolymer are heated and crosslinked to obtain the solid-state flexible conductive composite material.

[0012] Furthermore, the solid-state flexible conductive composite material is made of a conductive nanofluid. Its preparation method is as follows: A conductive composite material is formed by doping silver nanowires (AgNWs) into a polydimethylsiloxane (PDMS) matrix. The AgNWs nanoparticles are uniformly dispersed in the PDMS liquid medium to form a conductive nanofluid, which is heated, crosslinked, and cured to form the solid-state flexible conductive composite material. The PDMS serves as an elastic matrix to provide flexibility, and the AgNWs endow the material with conductivity by forming a conductive network.

[0013] Furthermore, the width of the microchannel is 200 ± 50 μm. The microchannel includes a 200-nm silicon nitride anti-permeation bottom layer formed by chemical vapor deposition; an intermediate layer with a 10-μm spin-coated perfluoropolyether coating and a contact angle > 110°; and a surface layer formed by sputtering a 50-nm gold film to prevent electrolytic corrosion.

[0014] An on-line device for detecting alkali leakage of electrolytic cell gaskets. The detector carrier includes at least an annular circuit board module wound around the periphery of the gasket between the end pressing plate and the electrode plate. Detection components are provided on several turns of the annular circuit board module to form a spatial sensor array. The annular circuit board module has a circumferential flexible circuit board arranged along the circumferential direction of the electrolytic cell and an axial flexible circuit board arranged along the axial direction of the electrolytic cell. The circumferential flexible circuit board and the axial flexible circuit board are arranged in a ladder shape.

[0015] Furthermore, several axial flexible circuit boards are distributed between two circumferential flexible circuit boards. The distance between the two circumferential flexible circuit boards is greater than the distance between the electrode plates. A circumferential telescopic compensation component is provided at the connection end of the two circumferential flexible circuit boards, and an axial telescopic compensation component is provided on the axial flexible circuit board.

[0016] The advantages and beneficial effects of the present invention are as follows: An on-line method for detecting alkali leakage of electrolytic cell gaskets has a fast response speed, high detection sensitivity, and high positioning accuracy. All key indicators comprehensively exceed traditional methods. In terms of economic benefits, it reduces operation and maintenance costs and reduces accident losses. It has high safety, upgrades from passive response to active protection, and completely solves the safety risks caused by alkali liquid leakage. Description of the Drawings

[0017] Figure 1 is an axonometric view of the on-line device for detecting alkali leakage of electrolytic cell gaskets of the present invention installed on the electrolytic cell; Figure 2 is an axonometric view of the alkali leakage monitoring device composed of the detector carrier in the present invention; Figure 3 is an explosion diagram between the detector carrier and the detection component in the present invention; Figure 4 is a front view of a single annular circuit board module in the present invention; Figure 5 is a structural diagram of the circumferential telescopic compensation component in the present invention; Figure 6 is a structural diagram of the ladder-shaped flexible circuit board unit in the present invention; Figure 7 is a structural diagram of the axial telescopic compensation component in the present invention; Figure 8 is a structural diagram of the positioning ring groove formed between two electrode plates in the present invention; In the figure: 1. Detector carrier; 2. Electrolytic cell; 3. Detection component; 4. Ring circuit board module; 5. Plate electrode; 6. Gasket; 7. Spatial sensor array; 8. Flexible circuit board unit; 9. Latitudinal expansion compensation component; 10. Latitudinal flexible circuit board; 11. Axial flexible circuit board; 12. Ladder-shaped; 13. Axial expansion compensation component; 14. Spring; 15. Adjusting screw; 16. Retaining piece; 17. Adjusting nut; 18. Pleated structure; 19. Step; 20. Positioning ring groove; 21. Positioning convex rod; 22. Perforation. Specific implementation manner

[0018] The following combines the accompanying drawings and embodiments to further describe the specific implementation manner of the present invention. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and cannot be used to limit the protection scope of the present invention.

[0019] A method for on-line detecting alkali leakage of the gasket of an electrolytic cell includes a deformable detector carrier 1, and the detector carrier 1 is arranged on the outer circumferential surface of the plate electrode 5 by deforming and conforming or maintaining a certain distance. Since the electrolytic cell 2 is usually cylindrical, a week of tie rods are pulled between the two end plates, and there is a certain distance between the tie rods and the plate electrode 5. The detector carrier 1 can be arranged within this interval distance. And the surface of the electrolytic cell 2 is a cylindrical curved surface. In this embodiment, the deformable detector carrier 1 can be adapted to be arranged on the surface of the electrolytic cell 2, and the surrounding design can form a dead-angle-free monitoring. In the prior art, relying on manual inspection, only the sides facing the inspection route can be visually inspected by the naked eye, while it is not convenient to inspect the back, top, and bottom surfaces of the electrolytic cell 2. The surrounding arrangement in this embodiment has the advantages of dead-angle-free, fully automatic, and timely monitoring.

[0020] Specifically, the detector carrier 1 is a flexible circuit board, enabling the detector carrier 1 to have degrees of freedom of deformation in the axial and / or radial directions of the electrolytic cell 2. The flexible circuit board is based on polyimide (PI) or polyester (PET) and can be bent and folded. Detection components 3 are arranged on the flexible circuit board. It can be understood that a reinforcing plate can be arranged on the flexible printed circuit board (FPC) to provide the installation foundation required by the detection components 3. Its deformation ability features bending, folding, twisting, and even winding into a cylindrical shape. Moreover, it is thin and suitable for use in scenarios with limited space. In this embodiment, it is applied between the electrode plates 5 of the electrolytic cell 2. Multiple layers of FPC can achieve complex wiring through metallized holes. A number of detection components 3 are integrated on the detector carrier 1. The number of detection components 3 forms a spatial sensor array 7 arranged in a surrounding manner around the electrolytic cell 2 at a specific number. The numbers of the detection components 3 correspond to the position codes at the preset monitoring points on the electrolytic cell 2 model. The data of each detection component 3 are sampled at a specific frequency to form a data chain, and each data chain is analyzed in real time. The gradient mutation of the data chain is used as the basis for leakage judgment, and the monitoring point position on the electrolytic cell 2 model is located. It can be understood that the spatial sensor array 7 composed of the detection components 3 actually uses the electrolytic cell 2 body as the basis for shape support, and utilizes the shape variability of the flexible circuit board to compensate for the minor axial or radial deformations generated by the electrolytic cell 2 during variable load operation. At the same time, the position of the detection components 3 is fixed by the flexible circuit board, and an electrical connection is also formed between the detection components 3 and the control module through the flexible circuit board. The control module issues detection instructions, and the corresponding detection components 3 collect certain data at specific positions on the electrolytic cell 2 and then transmit the data signal back to the control module through the flexible circuit board to form a data chain. The control module can analyze the data chain automatically or manually to obtain whether the working state of the corresponding data collection point is normal.

[0021] Specifically, as Figure 1-8 shown, the detector carrier includes at least an annular circuit board module 4 wound around the periphery of the gasket 6 between the end pressing plate and the electrode plate 5. The annular gasket 6 is clamped between the electrode plates 5 of the electrolytic cell 2. Then, when in use, at least an annular circuit board template is arranged around the gasket 6, so that the annular circuit board module 4 is arranged around the outer periphery of the corresponding gasket 6. For example, in the scenario of green hydrogen production by electrolysis, when the current density of the electrolytic cell 2 increases to more than 10,000 A / m², the Joule heat increases significantly, the temperature gradient in the gasket 6 area intensifies, and the leakage risk is high. Or in the application of renewable energy, such as wind power and photovoltaic power, their volatility causes the electrolytic cell 2 to start and stop frequently, and the gasket 6 bears periodic thermal stress, resulting in aging and leakage; when the electrolyte leaks onto the corresponding annular circuit board module 4, the monitoring data of its corresponding monitoring components will change significantly. By following the clues according to the changes, the corresponding leakage point can be found, greatly improving the detection accuracy.

[0022] Specifically, as an embodiment of the annular circuit board module 4, a detection component 3 is provided on each of several turns of the annular circuit board module 4 to form a spatial sensor array 7; the annular circuit board module 4 can adopt a modular detachable structure. For example, the annular circuit board module 4 is divided into six segments (each flexible circuit board unit 8 has an arc length of 60°) and connected by spring 14 thimbles, so as to adapt to different diameter electrodes 5, and at least one circumferential expansion compensation component 9 is provided at the six formed interfaces.

[0023] Furthermore, the flexible circuit board unit 8 has a circumferential flexible circuit board 10 arranged along the circumferential direction of the electrolytic cell 2 and an axial flexible circuit board 11 arranged along the axial direction of the electrolytic cell 2, and the circumferential flexible circuit board 10 and the axial flexible circuit board 11 are arranged in a ladder shape 12. Two circumferential flexible circuit boards 10 are arranged in parallel with each other. During installation, the two circumferential flexible circuit boards 10 can be respectively attached to the outer walls of the two electrodes 5, and several axial flexible circuit boards 11 arranged between the two circumferential flexible circuit boards 10 can be provided with detection components 3, so that several detection components 3 are distributed in an interval ring shape outside the gasket 6. It can be understood that corresponding detection components 3 can also be provided on the circumferential flexible circuit board 10 to monitor the relevant monitoring data of the electrode 5.

[0024] Furthermore, several axial flexible circuit boards 11 are distributed between the two circumferential flexible circuit boards 10. The distance between the two circumferential flexible circuit boards 10 is greater than the distance between the electrodes 5. A circumferential expansion compensation component 9 is provided at the connection end of the two circumferential flexible circuit boards 10, and an axial expansion compensation component 13 is provided on the axial flexible circuit board 11.

[0025] As an embodiment of the circumferential expansion compensation component 9, a structure of a spring 14 and an adjusting screw 15 can be adopted to realize a connection with adjustable elastic force, so that the circumferential flexible circuit board 10 can be tightly fixed on the electrolytic cell 2. Specifically, a spring 14 is connected to one end of the two circumferential flexible circuit boards 10 to be connected, an adjusting screw 15 is connected to the end of the spring 14, and a retaining piece 16 for the adjusting screw 15 to pass through is provided at the other end. After the adjusting screw 15 passes through the retaining piece 16, an adjusting nut 17 is screwed.

[0026] Specifically, as an embodiment of the axial expansion compensation component 13, a corrugated structure 18 is formed on the axial flexible circuit board 11. The corrugated structure 18 can be a prefabricated corrugation or a wavy structure on the flexible circuit board, so that it can deform according to the axial expansion and contraction of the electrolytic cell 2, release the deformation stress, so that it will not move its position after the repeated expansion and contraction deformation of the electrolytic cell 2, resulting in a change in the monitoring position, and always maintain monitoring, and it is not easy to be damaged after repeated deformation.

[0027] Further, steps 19 can be provided on both sides of the electrode plate 5. The steps 19 on two adjacent electrode plates 5 form a positioning ring groove 20 for installing the annular circuit board mold. The circumferential flexible circuit board 10 can be sleeved and positioned on the steps 19, and the axial flexible circuit board 11 is spanned across the gap between two electrode plates 5. A positioning convex rod 21 for positioning the circumferential flexible circuit board 10 can also be formed on the steps 19, and a through hole 22 matching with it is opened on the circumferential flexible circuit board 10. Moreover, the through hole 22 can be set in a waist-shaped hole, so as to provide the freedom degree of circumferential telescopic compensation.

[0028] As an embodiment, the detection component 3 includes a temperature detection sensor, and the temperature detection sensor is used to monitor the circumferential temperature change at a preset point. The temperature detection sensor is one or more of a grating temperature sensor, a thermistor, a flexible thin-film temperature sensor, a thermocouple, and an infrared temperature sensor. Its specific monitoring principle is that the circumferential temperature gradient of the gasket 6 is monitored by the temperature detection sensor. Because when leakage occurs, the local temperature drops by ≥2°C due to the evaporation and heat absorption of the lye at the leakage point. A data chain is formed through the temperature monitoring to analyze the temperature mutation situation.

[0029] The resistance value of the thermistor changes with temperature. Its advantages are low cost, fast response, and small volume. It can be directly printed or surface-mounted on a flexible circuit board (such as polyimide). Its disadvantage is poor linearity and calibration is required.

[0030] The grating temperature sensor is also small in volume and fast in response, suitable for corrosion-resistant environments, and has the advantage of high temperature detection accuracy.

[0031] The flexible thin-film temperature sensor utilizes the change of the thin-film resistance of metals (platinum, nickel) or carbon-based materials. It is designed specifically for flexibility and can withstand repeated bending. It can be integrated into printed electronics processes, such as inkjet printing. The customization cost is relatively high.

[0032] The thermocouple generates voltage based on the temperature difference between two metals and is high-temperature resistant. It can be designed into a flexible thin-film structure, such as a nickel-chromium / nickel-silicon thin film. Its disadvantage is that the signal is weak and an amplifier circuit is required.

[0033] The infrared temperature sensor detects the infrared energy radiated by an object. It is a non-contact measurement and can integrate a micro infrared probe on a flexible circuit board to perform infrared detection on the temperature of a specific area.

[0034] In actual use, the above temperature detection sensors can be adaptively selected according to user requirements or actual scenarios.

[0035] As another embodiment, a humidity detection sensor is used to monitor the circumferential humidity change at a preset point. The humidity detection sensor can detect the sudden change in humidity around the gasket 6. Due to the leakage of the electrolyte at the leakage point, the humidity at the leakage point will increase significantly. Specifically, during monitoring, when the humidity increase rate ≥ 3% / s, a warning is triggered.

[0036] The humidity detection sensor is one or more of a capacitive humidity sensor, a resistive humidity sensor, a flexible thin-film humidity sensor, and an optical fiber humidity sensor. Specifically, the capacitive humidity sensor has the advantages of high sensitivity and low power consumption and is suitable for flexible circuits; it can be printed or sprayed on a flexible substrate.

[0037] For the resistive humidity sensor, the resistance value of the moisture-absorbing material (such as electrolyte or polymer) changes with humidity. It can be set on a flexible substrate such as PET or polyimide, and carbon nanotube / polymer composite materials or graphene oxide are used as the humidity-sensitive materials. The advantages are simple structure, low cost, and easy integration.

[0038] The flexible thin-film humidity sensor changes its electrical properties by adsorbing water molecules through a thin-film material (such as alumina or polyelectrolyte) and is manufactured using magnetron sputtering, inkjet printing, or roll-to-roll (R2R) processes. The advantages are ultra-thin (micrometer level), bendable and conformable to curved surfaces; it can be integrated with other sensors (temperature, pressure); The optical fiber humidity sensor monitors based on the principle that the refractive index of the fiber grating or coating material changes with humidity. Its flexible design principle can use flexible optical fibers (such as polymer optical fibers) embedded in the FPC; a silica porous film is deposited by the sol-gel method to form a humidity-sensitive coating. The advantages are anti-electromagnetic interference, suitable for high-humidity or corrosive environments, and can be monitored in a long-distance distributed manner; The temperature and humidity signals outside the gasket 6 are collected in real time, and the sampling frequency ≥ 10 Hz. If one of the following conditions is met, a primary warning is triggered: the absolute value of the temperature gradient ≥ 2 °C / cm; the humidity increase rate ≥ 3% / s. If both occur simultaneously, a high-level alarm is triggered and an interlock response is started. Through the signal intensity difference of the sensor array and combined with the model of the electrolytic cell 2, the leakage point is located to the specific gasket 6 number (accuracy ±2 cm).

[0039] It can be understood that in order to increase durability and improve the protection effect, a polytetrafluoroethylene (PTFE) coating can be covered on the surfaces of the temperature detection sensor and the humidity detection sensor to make it resistant to strong alkali environments. The applicability improvements of various detection components 3 for the polytetrafluoroethylene (PTFE) coating are as follows: The metal joints of the thermocouple (such as nickel-chromium / nickel-silicon) are corrosion-resistant by themselves. The PTFE coating can cover the non-joint areas (such as leads or flexible substrates), exposing only the joint parts. For full encapsulation, breathable PTFE or an ultra-thin coating (<10μm) needs to be selected to avoid hindering heat conduction. A local coating process can be used to protect only the circuit part, and the joints are exposed through laser micro-holes.

[0040] For flexible thin-film temperature sensors (platinum / nickel thin films), the temperature-sensing layer of the thin-film sensor can be fully encapsulated with PTFE. Since it relies on the change of metal resistance and does not need to directly contact the environment, the insulation of PTFE does not affect the resistance measurement. The platinum thin film can be directly deposited on the PTFE substrate by magnetron sputtering to form an integrated corrosion-resistant structure.

[0041] The thermistor needs to avoid the PTFE completely wrapping the thermistor body, otherwise the response speed will be significantly reduced. Only the leads and solder joints can be coated, and the temperature-sensing part is exposed through micro-structures (such as openings), or a porous PTFE coating can be used.

[0042] For capacitive humidity sensors, if the PTFE completely covers the humidity-sensing layer, it will block the contact of water molecules and cause failure. Local breathable windows can be designed, such as laser drilling or nano-porous PTFE. Micro-scale pores with a pore diameter of 1 - 5μm are made on the PTFE coating to allow water molecules to pass through but block the penetration of alkaline liquids.

[0043] For fiber optic humidity sensors, the optical fiber itself can be fully encapsulated with PTFE, and only the humidity-sensing coating area (such as fiber Bragg gratings) needs to be locally exposed. The sol-gel method can be used to coat a porous SiO2 humidity-sensing layer on the surface of the optical fiber, and then PTFE is covered to protect the non-sensitive area.

[0044] For resistive humidity sensors, the PTFE full encapsulation will block the humidity contact, and the circuit part needs to be protected by selective coating. The humidity-sensing area is made of a hydrophilic material (such as graphene oxide), and the surrounding is isolated from the alkaline environment by PTFE.

[0045] The following issues should be noted when using the PTFE coating process: Coating thickness: Temperature sensors: ≤20μm (to avoid excessive thermal resistance). Humidity sensors: Local area ≤5μm (micro-hole design).

[0046] Adhesion enhancement: Flexible substrates (such as polyimide) need to be pretreated by plasma to improve the bonding force of PTFE.

[0047] Selective coating: Use masking technology or laser engraving to coat PTFE only in non-sensitive areas.

[0048] As an improved embodiment, the detection component 3 further includes a microchannel impedance sensor. A serpentine microchannel is etched on the side of the detector carrier 1 facing the electrolytic cell 2. For example, the microchannel has a line width of 200 μm and a depth of 150 μm. Further, the microchannel is designed with weather resistance. Specifically, the microchannel includes a 200-nm silicon nitride anti-permeation bottom layer formed by chemical vapor deposition; an intermediate layer of 10-μm perfluoropolyether coating spin-coated (contact angle > 110°); and a surface layer of 50-nm gold film sputtered to form anti-electrolytic corrosion.

[0049] A solid-state flexible conductive composite material is formed in the microchannel. It is silver nanowires (AgNWs) with a diameter of 50 nm and a length of 20 μm doped into a polydimethylsiloxane (PDMS) matrix (volume ratio 8%). The normal impedance value is stably maintained at 2.5 kΩ ± 5%. And a pH-responsive hydrogel layer is coated on the surface. At the leakage point, the electrolyte penetrates through the hydrogel layer into the microchannel to change the impedance value. At both ends of the serpentine microchannel, wires built into a flexible circuit board are connected to a control module, and the control module monitors the change in the impedance value of the solid-state flexible conductive composite material in the serpentine microchannel. The thickness of the pH-responsive hydrogel layer coated on the surface of the microchannel is 30 μm. When the alkali solution leaks, the pH-responsive hydrogel layer swells by 300% when encountering alkali (pH > 12), accelerating the inward penetration of the alkali solution.

[0050] When the alkali solution penetrates into the microchannel: AgNWs are dissolved by the alkali solution, resulting in a sudden drop in the local impedance value (sensitivity up to 0.8 Ω / μl).

[0051] Dual-threshold detection is set. Early warning threshold one: impedance drop rate ≥ 50 Ω / s (corresponding to leakage rate ≥ 0.2 ml / min). Alarm threshold two: absolute impedance value < 500 Ω (corresponding to leakage rate ≥ 1 ml / min).

[0052] As an embodiment of the solid-state flexible conductive composite material, the solid-state flexible conductive composite material is formed by uniformly embedding silver nanowires (AgNWs) as conductive fillers into a polydimethylsiloxane (PDMS) solid matrix. PDMS serves as an elastic matrix to provide flexibility, and AgNWs endow the material with conductivity by forming a conductive network. Then, the prepared flexible solid-state flexible conductive composite material is installed in the microchannel, and then the surface is encapsulated with a pH-responsive hydrogel layer.

[0053] The specific manufacturing method of the flexible solid-state flexible conductive composite material is as follows: Using vacuum-assisted filling, the PDMS precursor is infiltrated into the AgNWs network (indicating that it is linear), and an embedded structure is formed after curing. Then, the AgNWs and the PDMS prepolymer are heated and crosslinked to obtain the solid-state flexible conductive composite material.

[0054] As another embodiment of the solid-state flexible conductive composite material, the solid-state flexible conductive composite material is made of a conductive nanofluid, and its preparation method is as follows: A conductive composite material is formed by doping silver nanowires (AgNWs) in a polydimethylsiloxane (PDMS) matrix. The AgNWs nanoparticles are uniformly dispersed in the PDMS liquid medium to form a conductive nanofluid, and then cured by heating cross-linking to form a solid-state flexible conductive composite material. Similarly, PDMS is used as an elastic matrix to provide flexibility, and AgNWs endow the material with conductivity by forming a conductive network. The difference between this embodiment and the previous embodiment is that in this embodiment, the uncured liquid AgNWs-PDMS mixed raw material can be directly injected into the microchannel to make its shape more conform to the microchannel, and then cured and encapsulated with a hydrogel layer.

[0055] During detection, spatial positioning can be formed through the spatial sensor array 7. If an abnormality occurs in a certain monitoring area, it can be directly located to the corresponding part of the electrolytic cell 2, and a hierarchical response mechanism can be formed: Primary warning (single-index abnormality): The impedance drop rate of a single segment of the microchannel > 30 Ω / s; Start local purging (nitrogen flow rate 2 L / min).

[0056] Advanced alarm (multi-index composite): The impedance of any segment < 800 Ω and ΔT ≥ 1.5 °C / cm in the corresponding area; Trigger a 50% reduction in the current density of this electrolysis unit.

[0057] Emergency shutdown (confirm leakage): The impedance at the same position < 500 Ω and the humidity rise rate > 2% / s; Cut off the power supply of the corresponding end plate and activate the emergency sealant (silicone material with a swelling rate of 600%).

[0058] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for online detection of alkali leakage in electrolytic cell gaskets, characterized in that: It comprises a deformable detector carrier, and the detector carrier is arranged on the outer circumferential surface of the electrode plate by deforming and conforming to the shape or maintaining a certain distance; A number of detection components are integrated on the detector carrier. The detection components are specifically numbered and arranged around the electrolytic cell to form a spatial sensor array. The numbers of the detection components correspond to the position codes of the preset monitoring points on the electrolytic cell model. The data of each detection component is sampled at a specific frequency to form a data chain, and each data chain is analyzed in real time. The gradient mutation of the data chain is used as a basis for leakage judgment, and the data is located at the monitoring point on the electrolytic cell model.

2. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 1, characterized in that: The detection component includes a temperature detection sensor, which is used to monitor the circumferential temperature change at a preset point; the temperature detection sensor is one or more of a grating temperature sensor, a thermistor, a flexible film temperature sensor, a thermocouple, and an infrared temperature sensor.

3. A method for online detection of alkali leakage of electrolytic cell gasket according to claim 1 or 2, characterized in that: Humidity detection sensor, the humidity detection sensor is used to monitor the circumferential humidity changes at preset points; the humidity detection sensor is one or more of a capacitive humidity sensor, a resistive humidity sensor, a flexible film humidity sensor, and an optical fiber humidity sensor.

4. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 3, characterized in that: The detector carrier is a flexible circuit board, so that the detector carrier has a degree of freedom of deformation in the axial direction and / or radial direction of the electrolytic cell.

5. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 1, characterized in that: The detection component also includes a microchannel impedance sensor, in which a microchannel is etched on the side of the detector carrier facing the electrolytic cell, a solid flexible conductive composite material is formed in the microchannel, and a pH-responsive hydrogel layer is coated on the surface. At the leakage point, the electrolyte passes through the hydrogel layer and enters the microchannel to change the impedance value.

6. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 5, characterized in that: The solid-state flexible conductive composite material is formed by uniformly embedding silver nanowires (AgNWs) as conductive fillers in a polydimethylsiloxane (PDMS) solid matrix, infiltrating the PDMS precursor into the AgNWs network by vacuum-assisted filling, and forming an embedded structure after curing, and then heating and cross-linking the AgNWs and the PDMS prepolymer to obtain a solid-state flexible conductive composite material.

7. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 5, characterized in that: The solid-state flexible conductive composite material is made of conductive nanofluid, and its preparation method is as follows: silver nanowires (AgNWs) are doped in a polydimethylsiloxane (PDMS) matrix to form a conductive composite material, AgNWs nanoparticles are uniformly dispersed in a PDMS liquid medium to form a conductive nanofluid, and the solid-state flexible conductive composite material is formed by cross-linking and curing by heating.

8. The method for online detection of alkali leakage of electrolytic cell gasket according to claim 5, characterized in that: The microchannel has a line width of 200±50 μm and comprises a 200nm silicon nitride anti-penetration bottom layer deposited by chemical vapor phase; an intermediate layer of a 10μm perfluoropolyether coating by spin coating; and an anti-electrolytic corrosion surface layer formed by sputtering a 50nm gold film.

9. The device for online detection of alkali leakage of electrolytic cell gasket according to claim 1, characterized in that: The detector carrier includes at least an annular circuit board module that is arranged around the periphery of a gasket between the end pressure plate and the electrode plate, and detection components are provided on several circles of the annular circuit board modules to form a spatial sensor array; the annular circuit board module has a latitudinal flexible circuit board arranged along the circumference of the electrolytic cell, and an axial flexible circuit board arranged along the axial direction of the electrolytic cell, and the latitudinal flexible circuit board and the axial flexible circuit board are arranged in a ladder shape.

10. The device for online detection of alkali leakage of electrolytic cell gasket according to claim 9, characterized in that: A plurality of axial flexible circuit boards are distributed between two latitudinal flexible circuit boards, the spacing between the two latitudinal flexible circuit boards is greater than the spacing between the plates, a latitudinal telescopic compensator is provided at the connecting ends of the two latitudinal flexible circuit boards, and an axial telescopic compensator is provided on the axial flexible circuit board.

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