Alkaline hydrogen production diaphragm surface resistance testing device for simulating pressurization working condition

Abstract

The invention discloses an alkaline hydrogen production diaphragm surface resistance testing device for simulating a pressurization working condition. Comprising a left side end plate, a right side end plate, an insulation sealing gasket, an insulation electrolyte containing cavity, an electrode plate, a diaphragm fixing plate block and a fastening assembly, each electrolyte containing cavity is provided with a liquid injection / drainage connector and a gas pressurization connector, an electrolyte is injected to form a liquid phase, and a gas phase space is reserved above the liquid phase; the gas phase space is pressurized through an external gas source, a pressure regulating valve and a pressure monitoring part, so that controllable absolute pressure or differential pressure is formed on the two sides of the diaphragm by electrolyte, and the operation condition of the pressurized electrolytic cell is simulated; and then measuring system resistance by adopting an alternating current impedance method under target pressure, and calculating diaphragm surface resistance by combining blank resistance and the effective area. The device is simple in structure, good in sealing performance and controllable in pressure, obtained data are closer to real pressurization working conditions, and the device is suitable for electrical property evaluation and research of the alkaline electrolytic water diaphragm.

Description

Technical Field

[0001] This invention relates to the field of testing technology for hydrogen production through water electrolysis, and in particular to a device for testing the surface resistance of an alkaline hydrogen production diaphragm under controlled voltage conditions to simulate pressurized conditions. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is widely used due to its mature technology and low cost. The diaphragm, as a key component of the electrolyzer, directly affects the cell voltage drop and system energy consumption due to its sheet resistance. In industrial applications, alkaline electrolyzers are often operated at a certain pressure to improve hydrogen delivery efficiency and reduce subsequent compression costs. Simultaneously, absolute pressure changes or transient differential pressures may occur between the anode and cathode chambers during start-up, shutdown, load fluctuations, or system control. Under pressurized conditions, the pore structure and wetting state of the diaphragm may change, leading to deviations in sheet resistance from atmospheric pressure test results. Existing diaphragm sheet resistance tests are mostly conducted under atmospheric pressure or open environments, making it difficult to achieve pressure-controlled simulation tests under closed conditions, resulting in insufficient comparability of the obtained data with actual pressurized operating conditions. Therefore, developing an experimental device and method that allows for controllable adjustment of the pressure on both sides of the diaphragm in a closed system and conducts AC impedance testing at a target pressure is of great significance for obtaining diaphragm electrical performance data that more closely reflects real-world operating conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a device and method for testing the surface resistance of an alkaline hydrogen production diaphragm under different pressures based on gas-phase pressurization, overcoming the shortcomings of existing technologies such as uncontrollable test pressure and mismatch with the operating conditions of pressurized electrolyzers. The core concept of this invention is to establish mutually isolated electrolyte cavities on both sides of the diaphragm, and to create a controllable absolute pressure or differential pressure across the diaphragm by maintaining a gas phase space above the electrolyte and applying gas-phase pressurization; subsequently, the system resistance is measured using AC impedance spectroscopy under this pressure, thereby obtaining the surface resistance of the diaphragm under pressurized conditions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: First, the present invention provides an alkaline hydrogen production diaphragm surface resistance testing device for simulating pressurized working conditions, comprising: left and right end plates (31, 32), left and right electrode plates (41, 42), left and right insulating electrolyte cavities (51, 52), left and right diaphragm fixing plates (61, 62), multilayer insulating sealing gaskets and fastening components; The left and right end plates (left and right end plates (31, 21) are used for sealing devices; The left and right electrode plates (41, 42) are disposed on both sides of the diaphragm. The center of the electrode plate is provided with a through hole or a mesh opening, and the outer edge of the electrode plate is provided with tabs for electrical connection. The left and right insulating electrolyte cavities (51, 52) are provided with a through hole in the center and are respectively provided with a liquid injection / drainage interface and a gas pressurization interface, which are used to form a liquid phase electrolyte and a gas phase space above it in the cavity; The left and right diaphragm fixing plates (61, 62) are used to clamp the diaphragm to be tested; The multi-layer insulating gasket is divided into a large-opening insulating gasket and a small-opening insulating gasket. The large-opening insulating gasket is placed on both sides of the insulating electrolyte cavity, and the small-opening insulating gasket is placed on both sides of the electrode plate, diaphragm, and diaphragm fixing plate to seal the gaps between the structures. The fastening assembly includes an insulating bolt (8) and a nut (9) for pressing the above components along the thickness direction to form a sealed test cavity.

[0005] Preferably, the device also includes: an external gas source (10), a pressure regulating valve (11), and a pressure monitoring component (12) to pressurize the gas phase space. The external gas source (10) is connected to the pressure regulating valve (11) and the pressure monitoring component (12) to pressurize the gas phase space; The gas pressurization interface is connected to an external gas supply and pressure control unit. The pressure control unit includes at least a pressure regulating valve, a pressure monitoring component, and a safety pressure relief component, which are used to stably control the gas phase pressure at the target value.

[0006] Preferably, the injection / drainage interfaces of the left and right insulating electrolyte cavities (51, 52) are located at the lower part of the cavity. By injecting electrolyte, the liquid level is made higher than the central opening area of ​​the electrode plates (41, 42), while a gas phase space is reserved in the upper part of the cavity for gas pressurization.

[0007] Furthermore, preferably, the left and right insulating electrolyte cavities (51, 52) are isolated from each other and are independently pressurized through their respective gas pressurization interfaces to simulate the isobaric or differential pressure conditions on both sides of the diaphragm.

[0008] Preferably, the central opening of the electrode sheet (41, 42) is a mesh-like or porous structure to facilitate the flow of electrolyte.

[0009] In addition, the present invention also provides a method for measuring the surface resistance of an alkaline hydrogen production diaphragm under different pressures using any of the experimental apparatus described above, comprising the following steps: (1) Diaphragm pretreatment: Soak the diaphragm to be tested in an alkaline solution (such as 30 wt% KOH) for 24 h to fully wet it; (2) Assembly of the device: Stack the left end plate, sealing gasket, left electrolyte chamber, left electrode plate, left diaphragm fixing plate, diaphragm, right diaphragm fixing plate, right electrode plate, right electrolyte chamber, and right end plate in that order, and tighten them with a torque of 1 to 2 N·m. (3) Electrolyte injection: Electrolyte is injected through the injection / drainage ports of the left and right electrolyte cavities respectively, so that the electrolyte level is higher than the center opening of the electrode plate and a gas phase space is retained in the upper part of the cavity; (4) Pressurization and stabilization: Gas is introduced into the gas phase space of at least one side cavity, and the gas phase pressure is adjusted to the target pressure through the pressure regulating valve and maintained for a preset time to stabilize the pressure; (5) Electrochemical testing: Connect the electrode tabs to the electrochemical workstation and use the AC impedance method for testing, with a frequency range of 1 Hz to 10 Hz. 6 Hz; (6) Data processing: Read the real axis intercept of the Nyquist plot at the high-frequency end to calculate the resistance value, and then calculate the resistance value according to the formula R. A = (R Z R0)×A, where R Z For the diaphragm test resistor, R0 is the blank device resistance, and A is the effective test area; the calculated R... A This refers to the surface resistance of the diaphragm under a specific pressure.

[0010] Preferably, the target pressure in step (4) is 0.1-3.0 MPa; or it is set according to the working conditions of the electrolytic cell under test, and the pressure fluctuation is recorded in real time by the pressure monitoring component for data correction.

[0011] Furthermore, the experimental method of the present invention provides test results that can be used to evaluate the change in the surface resistance of the diaphragm under different pressures, explore the influence of pressure on the surface resistance of the diaphragm, and simulate real working conditions.

[0012] Preferably, in this invention, the end plate material is selected from polytetrafluoroethylene, polyetheretherketone, or a combination thereof; The insulating electrolyte cavity has a liquid inlet / outlet and a gas inlet / outlet, and the material is selected from polytetrafluoroethylene; The electrode sheet has its own tabs, and the material is selected from nickel, nickel alloy, stainless steel or titanium; The insulating and sealing gasket material is selected from polytetrafluoroethylene film, polyphenylene sulfide film, polyetheretherketone film, or a combination thereof; The diaphragm fixing plate is made of polytetrafluoroethylene; The fastening assembly includes an insulated screw and an insulated nut, and the material is selected from polytetrafluoroethylene, polyetheretherketone or a combination thereof; The left insulating electrolyte cavity, the left diaphragm fixing plate, the right diaphragm fixing plate, the right insulating electrolyte cavity, and the insulating sealing gasket are all provided with through holes of the same size in their centers. The size of the through holes is smaller than the area of ​​the diaphragm to be tested. The electrode sheet has a mesh-like opening in the central area to facilitate the flow of electrolyte.

[0013] In particular, the present invention preferably has the following characteristics: the thickness of the left end plate and the right end plate is 10-20 mm; the thickness of the left insulating electrolyte cavity and the right insulating electrolyte cavity is 5-20 mm; the thickness of the left diaphragm fixing plate and the right diaphragm fixing plate is 5-20 mm; the thickness of the left stainless steel sheet and the right stainless steel sheet is 0.3-1.0 mm; and the thickness of the insulating sealing gasket is 0.2-0.5 mm.

[0014] In particular, the bolt is larger than the thickness of the parts stacked together.

[0015] Assembly and usage method of the device: Stack the following components from left to right: left transparent end plate, insulating gasket, left insulating electrolyte cavity, insulating gasket, left electrode plate, insulating gasket, left diaphragm fixing plate, insulating gasket, diaphragm, insulating gasket, right diaphragm fixing plate, insulating gasket, right electrode plate, insulating gasket, right insulating electrolyte cavity, insulating gasket, and right transparent end plate. Then, use a torque wrench and bolt nuts to tighten the test device through the bolt holes to complete the assembly of the electrolytic cell. Tighten with a torque wrench to a torque of 1-2 N·m. An experimental method for determining the surface resistivity of an alkaline hydrogen production diaphragm using the aforementioned testing apparatus simulates actual operating conditions by controlling the pressure across the diaphragm through the introduction of different amounts of gas. The method includes the following steps: (1) Diaphragm pretreatment: Soak the diaphragm to be tested in an alkaline solution (such as 30 wt% KOH) for 24 h to fully wet it; (2) Assembly of the device: Stack the left end plate, sealing gasket, left electrolyte chamber, left electrode plate, left diaphragm fixing plate, diaphragm, right diaphragm fixing plate, right electrode plate, right electrolyte chamber, and right end plate in that order, and tighten them with a torque of 1 to 2 N·m. (3) Electrolyte injection: Electrolyte is injected through the injection / drainage ports of the left and right electrolyte cavities respectively, so that the electrolyte level is higher than the center opening of the electrode plate and a gas phase space is retained in the upper part of the cavity; (4) Pressurization and stabilization: Gas is introduced into the gas phase space of at least one side cavity, and the gas phase pressure is adjusted to the target pressure through the pressure regulating valve and maintained for a preset time to stabilize the pressure; (5) Electrochemical testing: Connect the electrode tabs to the electrochemical workstation and use the AC impedance method for testing, with a frequency range of 1 Hz to 10 Hz. 6 Hz; The beneficial effects of this invention are as follows: (1) More realistic working condition simulation: By controlling the pressure on both sides of the diaphragm, the working environment of the diaphragm in the anode and cathode chambers of the real electrolytic cell can be simulated. The measured surface resistance data is closer to the actual application and has important value for evaluating the performance degradation and pressure effect of the diaphragm under operating conditions.

[0016] (2) Pressure is controllable and repeatable: Pressure stabilization control is achieved through pressure regulating valve and pressure monitoring components, and comparable data at different pressure points can be obtained on the same device and the same sample.

[0017] (3) Supports isobaric and differential pressure testing: The two cavities are isolated from each other and can be pressurized independently, which can realize the simulation of pressurization conditions with isobaric pressure on both sides, and can also carry out performance research under differential pressure conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the test device of the present invention in an unassembled and disassembled state.

[0019] Figure 2 This is a schematic diagram of the overall structure of the testing device of the present invention in its assembled state.

[0020] Figure 3 This is a cross-sectional view of the end plate of the testing device of the present invention in a specific embodiment.

[0021] Figure 4 This is a cross-sectional view of the insulating electrolyte cavity in a specific embodiment of the testing device of the present invention.

[0022] Figure 5 This is a cross-sectional view of the electrode sheet in a specific embodiment of the testing device of the present invention.

[0023] Figure 6 This is a cross-sectional view of the diaphragm fixing plate in a specific embodiment of the testing device of the present invention.

[0024] Figure 7 This is a cross-sectional view of the small-opening insulating gasket and the large-opening insulating gasket in a specific embodiment of the testing device of the present invention.

[0025] Figure 8 This is a schematic diagram of a specific implementation of a pressurization experiment using the testing device of the present invention in a specific embodiment.

[0026] exist Figure 1 The experimental setup includes: left and right end plates (31, 32), left and right electrode plates (41, 42), left and right insulating electrolyte cavities (51, 52), left and right diaphragm fixing plates (61, 62), multi-layer insulating sealing gaskets, and fastening components.

[0027] exist Figures 3-7The diagram shows a cross-sectional view of the components of the testing apparatus of the present invention in a specific embodiment.

[0028] exist Figure 8 The schematic diagram of the specific implementation of the pressurization experiment includes an external air source (10), a pressure regulating valve (11), and a pressure monitoring component (12). Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0030] In one embodiment, the end plates (11, 21) are made of polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), or a combination thereof; the insulating electrolyte chambers (51, 52) are made of PTFE or PEEK; the electrode sheets (41, 42) are made of nickel, nickel alloy, stainless steel, or titanium; and the insulating sealing gaskets are made of PTFE film, polyphenylene sulfide (PPS) film, or PEEK film. A gas pressurization interface is provided at the top of the electrolyte chamber and connected to a pressure control unit, which includes a pressure regulating valve, a pressure gauge or pressure sensor, and a safety relief valve. During testing, electrolyte is injected to cover the central opening of the electrode sheets while maintaining a gas phase space. The gas phase space is then pressurized and stabilized before AC impedance testing.

[0031] Example 1 according to Figure 1 and Figure 2 As shown, the following components are stacked from left to right: left transparent end plate, insulating gasket, left insulating electrolyte cavity, insulating gasket, left electrode plate, insulating gasket, left diaphragm fixing plate, insulating gasket, insulating gasket, right diaphragm fixing plate, insulating gasket, right electrode plate, insulating gasket, right insulating electrolyte cavity, insulating gasket, and right transparent end plate. Using a torque wrench, bolts, and nuts, the electrolytic cell is tightened through the bolt holes on the entire assembly, completing the assembly of the testing device. This completes the assembly of the testing device of the present invention.

[0032] Example 2 Using the testing apparatus described in Example 1, the implementation process of this method is illustrated by taking the determination of the surface resistivity of a commercial diaphragm under different pressure environments as an example.

[0033] (1) Preparation before testing 1) Prepare a 30 wt% KOH basic alkaline solution as the electrolyte; 2) A commercially available diaphragm was soaked in a 30 wt% KOH basic alkaline solution for 24 hours; 3) Use tweezers to remove a commercial diaphragm and remove excess alkali solution from the diaphragm surface; (2) Assembly of the device 1) Assembly of an apparatus for testing blank resistance without a diaphragm. Reference Figure 1 Assemble the testing equipment in sequence; 2) such as Figure 2 As shown; tighten using a torque wrench with a torque of 1.5 N·m.

[0034] (3)Injection Electrolyte is injected through the injection / drainage ports of the electrolyte chambers on both sides until the liquid level is higher than the center opening area of ​​the electrode plate, and a gas phase space is reserved in the upper part of the chamber; the injection port valve is then closed.

[0035] (4) Pressurization and Stabilization Connect the gas source to the gas pressurization port via the pressure regulating valve; pressurize both chambers to the target pressure (e.g., 0.1 MPa, 0.5 MPa, 1.0 MPa, etc.) and stabilize the pressure for 5-10 minutes; if differential pressure testing is required, different pressures can be set for each side.

[0036] (5) Electrochemical testing Connect the electrode tabs to the electrochemical workstation and perform AC impedance testing. Test conditions: open circuit potential, 10mV sinusoidal perturbation, frequency range 10... 6 Hz-1Hz. The total resistance is obtained by reading the real intercept of each curve at the high-frequency end.

[0037] (6) Blank correction and calculation The resistance R0 of the blank device was measured under the same assembly and pressure conditions; the total resistance R was measured under the diaphragm condition. Z ; diaphragm surface resistance according to R A =(R Z The area is calculated as R0)×A, where A is the effective test area.

[0038] (7) Results Analysis By comparing the changes in RA at different pressure points, the electrical performance characteristics of the diaphragm under pressurized conditions are obtained, providing a basis for diaphragm selection and operating condition design.

[0039] As can be seen from the results of the above embodiments, the present invention can achieve the following technical effects: (1) More realistic working condition simulation: By controlling the pressure on both sides of the diaphragm, the working environment of the diaphragm in the anode and cathode chambers of the real electrolytic cell can be simulated. The measured surface resistance data is closer to the actual application and has important value for evaluating the performance degradation and pressure effect of the diaphragm under operating conditions.

[0040] (2) Pressure is controllable and repeatable: Pressure stabilization control is achieved through pressure regulating valve and pressure monitoring components, and comparable data at different pressure points can be obtained on the same device and the same sample.

[0041] (3) Supports isobaric and differential pressure testing: The two cavities are isolated from each other and can be pressurized independently, which can realize the simulation of pressurization conditions with isobaric pressure on both sides, and can also carry out performance research under differential pressure conditions.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for testing the surface resistance of an alkaline hydrogen production diaphragm under simulated pressurized conditions, characterized in that, include: Left and right end plates (31, 32), left and right electrode plates (41, 42), left and right insulating electrolyte cavities (51, 52), left and right diaphragm fixing plates (61, 62), multi-layer insulating sealing gaskets and fastening components; The left and right end plates (left and right end plates (31, 21) are used for sealing devices; The left and right electrode plates (41, 42) are disposed on both sides of the diaphragm. The center of the electrode plate is provided with a through hole or a mesh opening, and the outer edge of the electrode plate is provided with tabs for electrical connection. The left and right insulating electrolyte cavities (51, 52) are provided with a through hole in the center and are respectively provided with a liquid injection / drainage interface and a gas pressurization interface, which are used to form a liquid phase electrolyte and a gas phase space above it in the cavity; The left and right diaphragm fixing plates (61, 62) are used to clamp the diaphragm to be tested; The multi-layer insulating gasket is divided into a large-opening insulating gasket and a small-opening insulating gasket. The large-opening insulating gasket is placed on both sides of the insulating electrolyte cavity, and the small-opening insulating gasket is placed on both sides of the electrode plate, diaphragm, and diaphragm fixing plate to seal the gaps between the structures. The fastening assembly includes an insulating bolt (8) and a nut (9) for pressing the above components along the thickness direction to form a sealed test cavity.

2. The experimental apparatus according to claim 1, characterized in that: The device also has an external gas source (10), a pressure regulating valve (11) and a pressure monitoring component (12) to pressurize the gas phase space; The external gas source (10) is connected to the pressure regulating valve (11) and the pressure monitoring component (12) to pressurize the gas phase space; The gas pressurization interface is connected to an external gas supply and pressure control unit. The pressure control unit includes at least a pressure regulating valve, a pressure monitoring component, and a safety pressure relief component, which are used to stably control the gas phase pressure at the target value.

3. The experimental apparatus according to claim 1, characterized in that: The injection / drainage ports of the left and right insulating electrolyte cavities (51, 52) are located at the bottom of the cavity. By injecting electrolyte, the liquid level is made higher than the central opening area of ​​the electrode plates (41, 42). At the same time, a gas phase space is reserved in the upper part of the cavity for gas pressurization.

4. The experimental apparatus according to claim 3, characterized in that: The left and right insulating electrolyte cavities (51, 52) are isolated from each other and are independently pressurized through their respective gas pressurization interfaces to simulate the equal pressure or differential pressure conditions on both sides of the diaphragm.

5. The experimental apparatus according to claim 1 or 3, characterized in that: The center opening of the electrode plates (41, 42) is a mesh-like or porous structure to facilitate the flow of electrolyte.

6. An experimental method for determining the surface resistance of a membrane in alkaline water electrolysis using the experimental apparatus described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Diaphragm pretreatment: Soak the diaphragm to be tested in an alkaline solution for 24 h to fully wet it; (2) Assembly of the device: Stack the left end plate, sealing gasket, left electrolyte chamber, left electrode plate, left diaphragm fixing plate, diaphragm, right diaphragm fixing plate, right electrode plate, right electrolyte chamber, and right end plate in that order, and tighten them with a torque of 1 to 2 N·m. (3) Electrolyte injection: Electrolyte is injected through the injection / drainage ports of the left and right electrolyte cavities respectively, so that the electrolyte level is higher than the center opening of the electrode plate and a gas phase space is retained in the upper part of the cavity; (4) Pressurization and stabilization: Gas is introduced into the gas phase space of at least one side cavity, and the gas phase pressure is adjusted to the target pressure through the pressure regulating valve and maintained for a preset time to stabilize the pressure; (5) Electrochemical testing: Connect the electrode tabs to the electrochemical workstation and use the AC impedance method for testing, with a frequency range of 1Hz to 10Hz. 6 Hz; (6) Data processing: Read the real axis intercept of the Nyquist plot at the high-frequency end to calculate the resistance value, and then calculate the resistance value according to the formula R. A = (R Z R0)×A, where R Z For the diaphragm test resistor, R0 is the blank device resistance, and A is the effective test area; the calculated R... A This refers to the surface resistance of the diaphragm under a specific pressure.

7. The experimental method according to claim 6, characterized in that: The target pressure in step (4) is 0.1-3.0 MPa; or it can be set according to the working conditions of the electrolytic cell under test, and the pressure fluctuation is recorded in real time by the pressure monitoring component for data correction.

8. An experimental method according to claim 6 or 7 for evaluating the change in sheet resistance of a diaphragm under different pressures, exploring the effect of pressure on the sheet resistance of the diaphragm, and simulating real working conditions.

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