Proton exchange membrane water electrolysis cell bipolar plate corrosion monitoring system

Abstract

The invention relates to a proton exchange membrane water electrolysis cell bipolar plate corrosion monitoring system, the test system comprises two independent water electrolysis cells: a first water electrolysis cell (6) and a second water electrolysis cell (15), the water outlet of the first water electrolysis cell (6) is sequentially connected with a first peristaltic pump (3) and a first buffer pool (2) through pipelines, and then is connected with the liquid inlet of the second water electrolysis cell (15); a liquid outlet of the second water electrolysis tank (15) is sequentially connected with a second buffer tank (11) and a second peristaltic pump (10) through a pipeline and then is connected with a water inlet of the first water electrolysis tank (6), the first water electrolysis tank (6) is used for liquid storage, and the second water electrolysis tank (15) is used for an electrochemical corrosion reaction; the peristaltic pump drives the electrolyte to flow between the two water electrolysis cells, and the corrosion performance is tested under the simulated working environment of a metal bipolar plate of the water electrolysis cell of the proton exchange membrane. Compared with the prior art, the method has the remarkable advantages that the real service environment of the bipolar plate of the proton exchange membrane water electrolysis cell is highly restored, the corrosion condition of the bipolar plate can be reflected in real time, and the universality is high.

Description

Technical Field

[0001] The invention relates to the technical field of green hydrogen energy, and in particular to a bipolar plate corrosion monitoring system for a proton exchange membrane water electrolyzer. Background Art

[0002] With the large-scale exploitation and depletion of fossil energy such as oil and coal, the global demand for clean energy and environmental protection technology continues to increase. As an efficient hydrogen energy storage and release technology, proton exchange membrane water electrolysis cells are showing broad application prospects. Proton exchange membrane water electrolysis cells have the advantages of no pollution, low operating temperature, fast startup speed and easy operation. They directly use abundant water resources for electrolysis to produce high-purity hydrogen, and thus have become an important focus of attention in the research field.

[0003] As one of the key components of the proton exchange membrane water electrolysis cell, the bipolar plate plays an important role in conducting current, separating products and supporting membrane electrodes. It also undertakes the heat dissipation and water management functions of the entire water electrolysis system. The metal bipolar plate has the advantage of excellent mechanical properties, which provides convenience for the manufacture of highly thinned bipolar plates, which not only reduces the weight and volume of the water electrolysis stack, but also further improves the power density of the water electrolysis stack. In addition, it also has good electrical and thermal conductivity, low processing cost, and easy large-scale production, making metal bipolar plates the development direction of bipolar plates for proton exchange membrane water electrolysis cells.

[0004] However, the widespread application of metal bipolar plates still faces some challenges. The presence of a passivation film on the surface of the metal bipolar plate will lead to an increase in contact resistance, especially when the metal bipolar plates of the proton exchange membrane water electrolyzer work in harsh environments for a long time. Acidic environments, high temperatures, electrode potentials, saturated hydrogen and oxygen atmospheres, etc. are prone to corrosion, causing metal ion loss, resulting in a decrease in membrane conductivity and catalyst contamination, which reduces the output performance of the water electrolysis stack and shortens its life. According to the bipolar plate function and service environment requirements, the metal bipolar plate needs to be surface modified. By applying a coating on the surface of the metal bipolar plate, the conductivity and corrosion resistance of the metal plate can be improved, thereby extending the service life of the bipolar plate.

[0005] Existing technologies generally use water contact angle, contact resistance, electrochemical properties, etc. to understand the key characteristics of the coating, such as hydrophilicity, conductivity, and corrosion resistance. In addition, microscopic observation and chemical analysis can reveal the microstructure and composition of the coating. For example, scanning electron microscopy (SEM) can observe the surface and cross-sectional morphology of the sample at the initial stage and before and after corrosion, X-ray diffraction (XRD) can be used to determine the crystal structure of the substance, and X-ray photoelectron spectroscopy (XPS) can be used to confirm the chemical state of the surface composition and elements of the material. At present, researchers usually use an electrochemical three-electrode system to conduct experimental studies on the corrosion properties of metal bipolar plate surface coatings. This method involves measuring the corrosion current density of the sample under a specific polarization state to determine the corrosion resistance of the coating, providing a scientific basis for the optimal design of metal bipolar plate coatings and ensuring their reliability and performance under harsh operating conditions. Such as:

[0006] Chinese patent publication number CN115598053A discloses a method and device for evaluating the corrosion resistance of metal bipolar plates of fuel cells. The invention proposes a device for evaluating the corrosion performance of metal bipolar plates of fuel cells. A pressure pump is set to control the internal electrolyte pressure, which can simulate the corrosion state of metal bipolar plates under erosion corrosion. The innovation of this method is that it makes up for the defect that the corrosion of bipolar plates in the actual operating environment cannot be truly simulated when using static solution testing. However, it requires manual adjustment of the valve opening, the operation steps are relatively complicated, and it is mainly applicable to the field of fuel cells. The water electrolysis cell needs to operate in a corrosive solution saturated with hydrogen or oxygen. After the gas environment is introduced, the pressure cannot be guaranteed to be the same under the same pressure difference, which will affect the repeatability of the electrolyte flow behavior.

[0007] Chinese patent publication number CN 111198154 A discloses a continuous corrosion visualization test device for fuel cell metal bipolar plates. The invention proposes a real-time visualization test method that can successfully obtain the morphology and metallographic structure photos of the fuel cell metal bipolar plates during the corrosion process through an optical camera sensor, which is convenient for accurately evaluating the corrosion resistance of the metal bipolar plates. The device is equipped with an air inlet and an air outlet pipe connected to the cell body at the top of the corrosion cell, and gas can be introduced into the solution. However, if gas is continuously introduced during the test, bubbles will adhere to the electrode surface, thereby affecting the accuracy of the electrochemical corrosion performance test results. At the same time, this test device does not fully consider the impact of electrolyte erosion corrosion on the performance of metal bipolar plates, so this method is not suitable for corrosion performance testing of bipolar plates in proton exchange membrane water electrolysis cells.

[0008] In summary, the existing research results show that the current electrochemical corrosion test system is mainly aimed at fuel cell applications, and in the corrosion evaluation of the bipolar plate of the proton exchange membrane water electrolyzer, the difference between the gas-liquid two-phase environment and the actual service environment is not fully considered. At the same time, the potential impact of the erosion corrosion of the electrolyte on the performance of the plate is also ignored. Summary of the invention

[0009] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a corrosion performance testing system that truly simulates the working environment of the metal bipolar plate of the proton exchange membrane water electrolyzer, so as to realize the combined effects of erosion corrosion and electrochemical corrosion of saturated hydrogen or oxygen electrolyte.

[0010] The purpose of the present invention can be achieved by the following technical solutions: a proton exchange membrane water electrolysis cell bipolar plate corrosion monitoring system, the test system includes a fluid circulation system, a gas circulation system, an optical receiving system, an electrochemical workstation and a host computer. The fluid circulation system includes two independent water electrolysis cells: a first water electrolysis cell and a second water electrolysis cell, the outlet of the first water electrolysis cell is connected to the first peristaltic pump and the first buffer cell in turn through a pipeline, and then connected to the inlet of the second water electrolysis cell, the outlet of the second water electrolysis cell is connected to the second buffer cell and the second peristaltic pump in turn through a pipeline, and then connected to the inlet of the first water electrolysis cell, wherein the first water electrolysis cell is used for liquid storage, and the second water electrolysis cell is used for electrochemical corrosion reaction; the peristaltic pump drives the electrolyte to flow between the two water electrolysis cells, and simulates the working environment of the metal bipolar plate of the proton exchange membrane water electrolysis cell to perform corrosion performance testing. The first peristaltic pump is responsible for driving the electrolyte through the first buffer cell, and through the inlet on the side of the second water electrolysis cell, so that the electrolyte enters the second water electrolysis cell. The liquid outlet of the second water electrolysis cell is connected to the second buffer cell and the second peristaltic pump in sequence, and the electrolyte is finally directed back to the first water electrolysis cell, thereby realizing the interconnection of two independent water electrolysis cells. This process corresponds to the complete circulation path of the electrolyte.

[0011] Furthermore, the first water electrolysis cell comprises a constant temperature heating belt, an upper cover and a cell body, wherein the constant temperature heating belt surrounds the outside of the cell body of the first water electrolysis cell, wherein the cell body is connected to the air source through an air inlet pipe on the upper cover, and a flow meter and a pressure reducing valve are provided on the connecting pipeline, and the air outlet pipe is connected to the back pressure valve.

[0012] Furthermore, the upper cover is provided with at least four threaded holes, which are respectively used to connect the water inlet pipe, the water outlet pipe, the air inlet pipe and the air outlet pipe; each pipe on the upper cover relies on the through-hole screw to squeeze the O-ring to fill the gap between the pipe and the hole to form a sealing structure.

[0013] The gas circulation system includes a pressure reducing valve, a flow meter and a back pressure valve. The gas first reduces its pressure through the pressure reducing valve, then flows into the flow meter, and uses the air inlet pipe on the upper cover of the first water electrolysis cell to introduce the gas into the bottom of the electrolyte, and then rises to the surface of the electrolyte. The air outlet pipe is connected to the back pressure valve to maintain a constant pressure of 0.1 to 3 MPa inside the first water electrolysis cell. Finally, the gas enters the exhaust pipeline through the air outlet. This process corresponds to the complete circulation path of the gas.

[0014] The gas circulation system introduces gas into the electrolyte in two stages: high flow and low flow. In the first stage, the gas flow rate into the first water electrolysis cell is 20-30 ml / min by adjusting the pressure reducing valve, and the peristaltic pump is started to make the electrolyte flow. After at least 20 minutes of gas introduction, the electrolyte reaches a saturated state. In the second stage, low-flow gas is introduced into the electrolyte to maintain its saturation state, specifically by adjusting the pressure reducing valve to keep the flow meter value at 0.3-0.7 ml / min.

[0015] The built-in water pipe material of the peristaltic pump has the characteristics of withstanding sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, perchloric acid and their mixtures, with a pH range of 0 to 5 and a high temperature range of 50 to 200°. There are two opposite threaded holes on the side of the buffer tank, which are used for the entry and discharge of the electrolyte respectively.

[0016] Furthermore, the second water electrolysis cell comprises an upper fixture, a lower fixture, electrodes and an annular sealing ring, and the bipolar plate to be tested is fixed by the upper fixture and the lower fixture, and sealed by the annular sealing ring.

[0017] Furthermore, the electrodes include a working electrode, an auxiliary electrode and a reference electrode, wherein the working electrode is placed inside the lower fixture, and the auxiliary electrode and the reference electrode are placed on the side of the upper fixture, and the side of the upper fixture is also provided with a liquid inlet and a liquid outlet.

[0018] Furthermore, a V-shaped through hole is opened in the center of the upper clamp of the second water electrolysis cell, an observation window is arranged at the bottom of the V-shaped through hole, an optical sensor is arranged on the observation window, and the optical sensor receives the Raman signal in the corrosion process and transmits it to the host computer.

[0019] Furthermore, the distance between the lens of the optical sensor and the bipolar plate to be tested is 2 to 3 mm;

[0020] The observation window is made of quartz material.

[0021] Furthermore, the working electrode, auxiliary electrode and reference electrode are connected to an electrochemical workstation, and the electrochemical workstation is connected to a host computer.

[0022] The upper clamp is a structure with two ends concave toward the middle, and its cross-sectional shape is similar to the letter "H".

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] According to the working environment requirements of the metal bipolar plate of the proton exchange membrane water electrolyzer, the present invention needs to meet the following key criteria when testing the electrochemical corrosion performance: first, ensure that the clamped bipolar plate fits tightly with the fixture without gaps; second, the electrolyte should reach a saturated state of hydrogen or oxygen to simulate the gas environment in actual working conditions; finally, a flowing electrolyte should be used during the test to restore the actual effect of the electrolyte flushing on the surface of the bipolar plate. The present invention fully considers these criteria and adopts the synergy between the various parts of the system to ensure that the test environment and the actual working environment are seamlessly matched, thereby obtaining accurate and reliable electrochemical performance evaluation results.

[0025] The present invention improves the single water electrolysis cell used in the past and replaces it with two independent water electrolysis cells, which are used for liquid storage and reaction respectively. By introducing a peristaltic pump, the electrolyte is connected between the two separate water electrolysis cells. During the test, the electrolyte flow is controllable and stable, and the corrosion and flushing effect of the electrolyte on the bipolar plate in the actual operation of the proton exchange membrane water electrolysis cell is truly simulated. In the traditional single water electrolysis cell, bubbles may gather on the electrode surface when gas is directly introduced, and the flowing electrolyte can quickly take away these bubbles, ensuring the electrochemical corrosion performance of the bipolar plate The reliability and accuracy of the test results; in addition, the present invention focuses on the design of the saturated gas atmosphere. The air inlet end is connected to a pressure reducing valve and a flow meter to realize real-time monitoring and control of the gas flow. The air outlet is connected to a back pressure valve to keep the pressure in the first water electrolysis cell stable. Two stages are designed to introduce gas into the electrolyte. In the first stage, high-flow gas is introduced into the electrolyte to ensure that the electrolyte is in a saturated state. In the second stage, the gas flow is reduced. This is because the entire test device is sealed, and only the gas consumed during the corrosion test needs to be supplemented to ensure the saturated state of the solution, thereby reducing the amount of gas used and reducing losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a connection diagram of a water electrolysis cell corrosion monitoring device;

[0027] Figure 2 A schematic diagram of the connection assembly of the first water electrolysis cell;

[0028] Figure 3 for Figure 2 Middle AA section view;

[0029] Figure 4 A schematic diagram of the assembly of the second water electrolysis cell;

[0030] Figure 5 for Figure 4Middle BB section view;

[0031] Figure 6 This is a schematic diagram of a through-hole screw;

[0032] Figure 7 It is a schematic diagram of an O-ring;

[0033] Figure 8 The current density curves were measured under oxygen and non-oxygen conditions.

[0034] Symbols in the figure: host computer 1, first buffer tank 2, first peristaltic pump 3, water outlet 4, air outlet 5, first water electrolysis cell 6, air inlet 7, constant temperature heating belt 8, water inlet 9, second peristaltic pump 10, second buffer tank 11, pressure reducing valve 12, flow meter 13, liquid outlet 14, second water electrolysis cell 15, optical sensor 16, reference electrode 17, auxiliary electrode 18, liquid inlet 19, working electrode 20, back pressure valve 21, electrochemical workstation 22, cell body 23, O-ring 24, through-hole screw 25, upper cover 26, bipolar plate 27, annular sealing ring 28, observation window 29, upper clamp 30, lower clamp 31;

[0035] Figure 1 middle: For the circuit, For waterways, For the gas path. DETAILED DESCRIPTION

[0037] The device and implementation process of the present invention are further described below in conjunction with the accompanying drawings: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] like Figure 1-7 As shown, a system for monitoring the corrosion performance of metal bipolar plates in a proton exchange membrane water electrolysis cell includes a gas circulation system, a fluid circulation system, an optical receiving system, an electrochemical workstation and a host computer. The system consists of two independent water electrolysis cells, one of which is used for liquid storage and the other for reaction. A peristaltic pump is used to push the electrolyte to flow between the two water electrolysis cells, which helps to avoid the problem of inaccurate results due to insufficient consideration of the flushing of the corrosive electrolyte, and also solves the defect of unstable test results caused by the accumulation of bubbles on the electrode surface. Specifically,

[0040] The fluid circulation system is mainly composed of a first water electrolysis cell 6 and a second water electrolysis cell 15. The electrolyte flow outlet of the first water electrolysis cell 15 is connected to the first peristaltic pump 3, and the first peristaltic pump 3 is responsible for driving the electrolyte through the first buffer cell 2 and entering the second water electrolysis cell 15 through the liquid inlet 19 on the side of the second water electrolysis cell 15. The liquid outlet 14 of the second water electrolysis cell 15 is connected to the second buffer cell 11 and the second peristaltic pump 10 in sequence, and finally the electrolyte is redirected back to the first water electrolysis cell 3, so that the two independent water electrolysis cells are connected to each other. This process corresponds to the complete circulation path of the electrolyte. Figure 1 .

[0041] Among them, Figures 1 to 3 As shown, the first water electrolysis cell 6 includes a constant temperature heating belt 8, an upper cover 26 and a cell body 23. The constant temperature heating belt 8 is used to heat the electrolyte outside the first water electrolysis cell 6. There are at least four threaded holes on the upper cover 26, which are a water inlet 9, a water outlet 4, an air inlet 7 and an air outlet 5. The four inlets and outlets are filled with the gaps between the pipes and the holes through through-hole screws 25 and O-rings 24; the air inlet 7 is connected to the flow meter 13 and the pressure reducing valve 12 in sequence for controlling and measuring the gas flow, and the air outlet 5 is connected to the back pressure valve 21; the water outlet 4 is connected to the first peristaltic pump 3, the first buffer tank 2 and the liquid inlet 19 of the second water electrolysis cell 15 in sequence through a hose; the electrolyte enters the second buffer tank 11 and the second peristaltic pump 10 through the liquid outlet 14 of the second water electrolysis cell 15, and finally returns to the water inlet 9 of the first water electrolysis cell. The whole process corresponds to the complete path of the electrolyte flow;

[0042] like Figure 1 , 4 As shown in Figures 5 to 5, the second water electrolysis cell 15 assembly includes an upper clamp 30, a lower clamp 31, three electrodes, an annular sealing ring 28 and a bipolar plate 27. The bipolar plate is fixed by the cooperation between the upper clamp 30 and the lower clamp 31. The working electrode 20 is placed on the side of the lower clamp, and the reference electrode 17 and the auxiliary electrode 18 as well as the relative liquid inlet 19 and the liquid outlet 14 are placed on the side of the upper clamp. The three-electrode system is connected to the electrochemical workstation 22 for collecting the electrochemical corrosion performance test results and transmitting them to the host computer 1; the bottom of the V-groove of the upper clamp is an observation window 29, and the upper part of the upper clamp is an optical sensor 16 for receiving Raman signals during the corrosion process and transmitting the results to the host computer 1.

[0043] like Figures 6-7 As shown, the O-ring 24 is placed in the hole of the upper cover, and the through-hole screw squeezes the sealing ring to ensure the sealing during installation;

[0044] The flow meter 13 is used to monitor the flow change of the gas in the pipeline in real time;

[0045] The upper clamp 30 and the lower clamp 31 are made of high temperature and acid resistant materials, and the clamping surfaces have precise flatness and small roughness;

[0046] Two peristaltic pumps are used to control the electrolyte flow rate to be stable, and the built-in water pipes of the peristaltic pumps are acid-resistant and high-temperature-resistant water pipes.

[0047] The two buffer tanks can be used as electrolyte flow buffer components to prevent the peristaltic pump from directly transporting and extracting electrolyte to the second water electrolysis tank, thereby reducing the disturbance of the electrolyte.

[0048] The side of the buffer tank is provided with a liquid inlet and a liquid outlet opposite to each other.

[0049] The host computer can respectively obtain the Raman signal received by the optical receiving system and the electrochemical data measured by the electrochemical workstation.

[0050] The working process of this embodiment:

[0051] Step 1: Cut the metal bipolar plate sample into a suitable size as required, and fasten it into the second water electrolysis cell 15 by means of the upper clamp 30 and the lower clamp 31 using the sealing function of the annular sealing ring. In addition, the reference electrode 17 and the auxiliary electrode 18 are installed in the second water electrolysis cell 15 by means of a combination of through-hole screws 25 and O-rings 24;

[0052] Step 2: Pour an acidic solution of diluted H2SO4 with a pH value of 3 and 0.5ppm HF into the first water electrolysis cell 6, and on the premise of ensuring that the upper cover 26 is tightly connected to the cell body 23, start the power supply of the constant temperature heating belt 8 wrapped around the outside of the first water electrolysis cell 6, set the temperature to 80°C and start heating;

[0053] Step 3: Connect the gas circulation system, connect the inlet pipe end to the oxygen cylinder, connect the outlet pipe end to the exhaust pipe, and connect the components of the fluid circulation system in sequence;

[0054] Step 4: Set the pressure of the back pressure valve 21 to 1 MPa, then open the oxygen cylinder valve, adjust the pressure reducing valve 12 until the flow meter 13 shows that the gas flow rate is 25 ml / min, the gas continues to be injected into the solution through the air inlet 7, and start the peristaltic pump to make the electrolyte flow;

[0055] Step 5: Connect the three electrodes to the electrochemical workstation, create the configuration parameters for the constant potential polarization experiment, set the test potential to 1.6 V, and ensure that the wires of the optical receiving system are connected correctly.

[0056] Step 6: After oxygen is continuously introduced for 25 minutes, the electrolytes of the two water electrolysis cells have reached saturation and the flow of the electrolyte has stabilized. The pressure reducing valve is adjusted again until the flow meter shows a gas flow rate of 0.5 ml / min, and this flow rate is maintained unchanged during the subsequent tests;

[0057] Step 7: Turn on the power of the potentiostat and optical sensor, collect and analyze data.

[0058] The advantages of this embodiment are: Figure 8 As shown, the focus is on the regulation of saturated gas environment (see Figure 8 The oxygen curve in the middle) fully considers the influence of saturated gas electrolyte on the corrosion process; in order to reduce the violent disturbance of the electrolyte caused by the peristaltic pump driving the electrolyte to flow directly into and out of the second water electrolytic cell, a buffer cell is introduced between the peristaltic pump and the second water electrolytic cell. This buffer cell transition design is intended to maintain the stability of the electrolyte; the use of advanced in-situ observation technology can not only obtain electrochemical data including corrosion current, corrosion potential and AC impedance at different corrosion times through the three-electrode system, but also obtain Raman signals in the whole corrosion process through the optical receiving system, which is used to judge the changes in the plate material during the corrosion process, which is conducive to better analysis of the corrosion behavior of the bipolar plate.

[0059] Example 2

[0060] This embodiment is for corrosion tests that do not require saturated gas electrolyte or corrosion tests that do not consider the influence of gas. There is no need to introduce a gas circulation system to control the inflow and discharge of gas, and the experiment can be carried out quickly, making the entire test system more applicable.

[0061] Compared with Example 1, the gas inlet and outlet on the cover of the first water electrolysis cell 6 in the system of this embodiment is in a closed state and is not connected to a gas source, as follows:

[0062] The water electrolysis cell comprises a first water electrolysis cell and a second water electrolysis cell which are interconnected. The first water electrolysis cell 6 comprises a constant temperature heating belt 8, an upper cover 26 and a cell body 23. The constant temperature heating belt 8 is used to heat the electrolyte outside the first water electrolysis cell 6. The upper cover has a water inlet 9 and a water outlet 4. The water inlet and outlet are filled with a through-hole screw 25 and an O-ring 24 to fill the gap between the pipe and the hole; the water outlet is connected to the first peristaltic pump 3, the first buffer tank 2 and the liquid inlet 19 of the second water electrolysis cell 15 in sequence through a hose. The electrolyte enters the second buffer tank 11 and the second peristaltic pump 10 through the liquid outlet 14 of the second water electrolysis cell 15, and finally returns to the water inlet 9 of the first water electrolysis cell. The whole process corresponds to The complete path of electrolyte flow; the second water electrolysis cell assembly includes an upper clamp 30, a lower clamp 31, three electrodes, an annular sealing ring 28 and a bipolar plate 27. The bipolar plate is fixed by the mutual cooperation of the upper clamp 30 and the lower clamp 31. The working electrode 20 is placed on the side of the lower clamp, and the reference electrode 17 and the auxiliary electrode 18 and the relative liquid inlet 19 and the liquid outlet 14 are placed on the side of the upper clamp. The three-electrode system is connected to the electrochemical workstation 22 for collecting the electrochemical corrosion performance test results and transmitting them to the host computer 1; the bottom of the V-groove of the upper clamp is an observation window 29, and the upper part of the upper clamp is an optical sensor 16 for receiving Raman signals during the corrosion process and transmitting the results to the host computer 1.

[0063] The O-shaped sealing ring is placed in the hole of the upper cover, and the through-hole screw squeezes the sealing ring to ensure the sealing during installation;

[0064] The upper and lower clamps are made of high temperature and acid resistant materials, and the clamping surfaces have precise flatness and small roughness;

[0065] The peristaltic pump can control the electrolyte flow to be stable.

[0066] The built-in water pipe of the peristaltic pump is an acid-resistant and high-temperature-resistant water pipe.

[0067] The buffer tank can be used as an electrolyte flow buffer component to prevent the peristaltic pump from directly transporting and extracting electrolyte to the second water electrolysis tank, thereby reducing the disturbance of the electrolyte.

[0068] The side of the buffer tank is provided with a liquid inlet and a liquid outlet opposite to each other.

[0069] The host computer can respectively obtain the Raman signal received by the optical receiving system and the electrochemical data measured by the electrochemical workstation.

[0070] The working process of this embodiment:

[0071] Step 1: Cut the metal bipolar plate sample into a suitable size as required, and fasten it into the second water electrolysis cell 15 by means of the upper clamp 30 and the lower clamp 31 using the sealing function of the annular sealing ring. In addition, the reference electrode 17 and the auxiliary electrode 18 are installed in the second water electrolysis cell 15 by means of a combination of through-hole screws 25 and O-rings 24;

[0072] Step 2: Pour an acidic solution of diluted H2SO4 with a pH value of 3 and 0.5ppm HF into the first water electrolysis cell 6, and on the premise of ensuring that the upper cover 26 is tightly connected to the cell body 23, start the power supply of the constant temperature heating belt wrapped around the outside of the first water electrolysis cell 6, set the temperature to 80°C and start heating;

[0073] Step 3: Use non-through-hole screws to seal the air inlet and the air outlet on the upper cover 26 of the first water electrolysis cell, then connect the components of the fluid circulation system in sequence, and then start the peristaltic pump to let the electrolyte flow;

[0074] Step 4: Connect the three electrodes to the electrochemical workstation, create the configuration parameters for the constant potential polarization experiment, set the test potential to 1.6 V, and ensure that the wires of the optical receiving system are connected correctly.

[0075] Step 5: Turn on the power of the electrochemical workstation and the optical sensor, collect and analyze the data.

[0076] The advantages of this embodiment are: Figure 8 For corrosion tests that do not require saturated gas electrolyte or do not consider the effect of gas (see Figure 8 There is no need to introduce a gas circulation system to control the inflow and discharge of gas, so the experiment can be carried out quickly, making the whole test system more applicable.

Claims

1. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system, characterized in that: The test system comprises two independent water electrolysis cells: a first water electrolysis cell (6) and a second water electrolysis cell (15); the water outlet of the first water electrolysis cell (6) is connected to a first peristaltic pump (3) and a first buffer cell (2) in sequence through a pipeline, and then connected to a liquid inlet of the second water electrolysis cell (15); the liquid outlet of the second water electrolysis cell (15) is connected to a second buffer cell (11) and a second peristaltic pump (10) in sequence through a pipeline, and then connected to a water inlet of the first water electrolysis cell (6); the first water electrolysis cell (6) is used for liquid storage, and the second water electrolysis cell (15) is used for electrochemical corrosion reaction; the peristaltic pump drives the electrolyte to flow between the two water electrolysis cells, and performs a corrosion performance test in a simulated working environment of a metal bipolar plate of a proton exchange membrane water electrolysis cell.

2. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 1, characterized in that: The first water electrolysis cell (6) comprises a constant temperature heating belt (8), an upper cover (26) and a cell body (23), wherein the constant temperature heating belt (8) surrounds the outside of the first water electrolysis cell body (23), wherein the cell body (23) is connected to an air source via an air inlet pipe on the upper cover (26), and a flow meter (13) and a pressure reducing valve (12) are provided on the connecting pipeline, and the air outlet pipe is connected to a back pressure valve (21).

3. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 2, characterized in that: The upper cover (26) is provided with at least four threaded holes, which are respectively used to connect the water inlet pipe, the water outlet pipe, the air inlet pipe and the air outlet pipe; each pipe on the upper cover (26) relies on the through-hole screw (25) to squeeze the O-type sealing ring (24) to fill the gap between the pipe and the hole to form a sealing structure.

4. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 2, characterized in that: The gas from the gas source is reduced in pressure by the pressure reducing valve (12) and then flows into the flow meter (13), then enters the bottom of the electrolyte in the first water electrolysis cell (6), and then rises to above the surface of the electrolyte, maintaining a constant pressure inside the first water electrolysis cell (6) between 0.1 and 3 MPa. Finally, the gas enters the exhaust pipeline through the outlet pipe.

5. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 2, characterized in that: The gas flow rate entering the first water electrolysis cell (6) is controlled to be 20-30 ml / min by adjusting the pressure reducing valve (12), and the peristaltic pump is started at the same time to allow the electrolyte to flow. After the electrolyte reaches a saturated state, the pressure reducing valve (12) is adjusted to keep the gas flow rate entering the first water electrolysis cell (6) at 0.3-0.7 ml / min, so that the electrolyte is maintained in a saturated state.

6. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 1, characterized in that: The second water electrolysis cell (15) comprises an upper clamp (30), a lower clamp (31), electrodes and an annular sealing ring (28); the bipolar plate to be tested is fixed by the upper clamp (30) and the lower clamp (31), and is sealed by the annular sealing ring (28).

7. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 6, characterized in that: The electrodes include a working electrode (20), an auxiliary electrode (18) and a reference electrode (17), wherein the working electrode (20) is placed inside the lower fixture (31), and the auxiliary electrode (18) and the reference electrode (17) are placed on the side of the upper fixture (30), and the side of the upper fixture (30) is also provided with a liquid inlet and a liquid outlet.

8. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 1 or 6, characterized in that: A V-shaped through hole is provided at the center of the upper fixture (30) of the second water electrolysis cell (15), an observation window is provided at the bottom of the V-shaped through hole, and an optical sensor (16) is provided on the observation window. The optical sensor (16) receives the Raman signal during the corrosion process and transmits it to the host computer (1).

9. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 8, characterized in that: The distance between the lens of the optical sensor (16) and the bipolar plate to be tested is 2 to 3 mm; The observation window is made of quartz material.

10. A proton exchange membrane water electrolyzer bipolar plate corrosion monitoring system according to claim 7, characterized in that: The working electrode (20), the auxiliary electrode (18) and the reference electrode (17) are connected to an electrochemical workstation (22), and the electrochemical workstation (22) is connected to a host computer (1).

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