An aging test method for an electric hydrogen production system simulating fluctuation conditions of a new energy microgrid

Abstract

The application discloses a kind of simulation new energy microgrid fluctuation working condition's aging test method of hydrogen production system of electric system.The method of the application comprises: selecting multiple identical proton exchange membrane electrolytic cell and these equipment are divided into four groups, water is introduced into the anode, different current density is maintained, so that each group electrolytic cell is in different fluctuation working condition condition synchronous operation;Every interval equivalent time, part of electrolytic cell in each group is stopped running, and is repeated several times, obtains electrolytic cell of different running time, then these electrolytic cell key components are taken out, the influence of different conditions on the performance aging of key components in different time is analyzed.The application can simulate new energy microgrid real fluctuation working condition by multi-working condition coupling, can obtain the attenuation data of key components synchronously, comprehensively evaluates electrolytic cell overall life;Aging test period can be shortened to 1 / 10~1 / 5, improves aging efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy technology and relates to electro-hydrogen production, specifically an aging test method for an electro-hydrogen production system that simulates the fluctuating operating conditions of a new energy microgrid. Background Technology

[0002] Proton exchange membrane (PEM) electrolysis of water is a common method for hydrogen production. The key components of a PEM electrolyzer include the proton exchange membrane, catalyst layer, gas diffusion layer, and bipolar plates. These key components age with the chemical reaction, causing changes in parameters such as conductivity and permeability, thus reducing the electrolyzer's hydrogen production performance. Aging (durability) tests on PEM electrolyzers can be used to evaluate the performance and durability of the device under specific conditions. Accelerated aging tests are a method that accelerates the aging process by simulating test environments higher than normal operating conditions, aiming to quickly assess the performance changes and lifespan of the electrolyzer during long-term operation. These tests often involve long-term continuous operation under conditions such as high temperature, high pressure, and rapid changes in current density. The results of these tests are crucial for improving the reliability and durability of the electrolyzer.

[0003] Some existing testing methods only target single components or static operating conditions, failing to reflect the dynamic impact of photovoltaic power fluctuations and hydrogen storage state changes on the electrolyzer in new energy microgrids. For example, the patent application "An accelerated test method for the durability of the gas diffusion layer of a proton exchange membrane fuel cell" (publication number CN107039668A) from Wuhan University of Technology uses a three-electrode system to conduct aging tests on the gas diffusion layer. This method cannot reflect the specific degradation of the gas diffusion layer under real-world operating conditions, and its results do not explain the performance degradation of the entire electrolyzer. The patent application "A method for evaluating the durability of a single cell, a durability evaluation device, a durability evaluation procedure, and a single cell of a fuel cell" (publication number CN101536230A) from Sumitomo Chemical Co., Ltd. of Japan analyzes the durability of a single cell using finite element modeling software, analyzing factors such as water distribution and stress changes. However, this method fails to simulate the frequent changes in operating conditions under actual circumstances. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the defects of the existing technology and provide an aging test method for an electro-hydrogen production system that simulates the fluctuating operating conditions of a new energy microgrid. This method simulates the real fluctuating operating conditions of a new energy microgrid through multi-condition coupling and performs durability tests on the proton exchange membrane electrolyzer. This allows for the simultaneous acquisition of attenuation data of key components such as the proton exchange membrane, catalyst layer, gas diffusion layer, and bipolar plate, so as to comprehensively evaluate the overall lifespan of the electrolyzer. The aging test cycle can be shortened to 1 / 10 to 1 / 5, improving the aging efficiency.

[0005] Therefore, the present invention adopts the following technical solution: an aging test method for an electric hydrogen production system simulating fluctuating operating conditions of a new energy microgrid, comprising:

[0006] Multiple identical proton exchange membrane electrolyzers were selected and divided into four groups. Water was introduced into their anodes, and different current densities were set so that each group of electrolyzers operated synchronously under different fluctuating conditions. The fluctuating conditions were stable conditions, overload conditions, frequent start-stop conditions, and large load variation conditions.

[0007] At equal intervals, some electrolytic cells in each group were stopped from operating, and this process was repeated several times to obtain electrolytic cells with different operating times. Then, the key components in these electrolytic cells were removed, and the effects of different conditions at different times on the performance aging of the key components were analyzed.

[0008] Furthermore, the stable operating condition is as follows: when the photovoltaic system power is within the range of grid load power fluctuation, the hydrogen storage system has not reached saturation, and the electrolyzer operates at normal power; the overload operating condition is as follows: when the photovoltaic system power exceeds the range of grid load power fluctuation, and the hydrogen storage system has not reached saturation, the electrolyzer operates beyond its rated load; the large load change operating condition is as follows: when the photovoltaic system power is about to exceed the range of grid load power fluctuation, and the hydrogen storage system is about to reach saturation, the electrolyzer changes its load in stages at its rated power; the frequent start-stop operating condition is as follows: when the photovoltaic system power is unstable, and the hydrogen storage system reaches saturation, the electrolyzer needs to be frequently started and stopped to stabilize the grid load, and the electrolyzer operates at a constant rated current density.

[0009] Furthermore, the constraints of the fluctuating operating condition are as follows:

[0010] The aforementioned stable operating condition: P pmax ≥ P nmax 20% < E h %≤80%;

[0011] The overload condition described: P pmax ≥ P nmax , E h %≤20%;

[0012] The aforementioned large load variation conditions: P pmax ≥ P nmax , E h % > 80%;

[0013] The aforementioned frequent start-stop conditions:P pmax < P nmax , E h %≤20%, rapid start-up of the electrolytic cell; P pmax < P nmax 20% < E h %, the electrolytic cell stopped working;

[0014] in, P nmax This represents the maximum power of the power grid load. P pmax This represents the maximum power generation capacity of the photovoltaic system. E h For the capacity of the hydrogen storage system, P hmax This represents the maximum operating power of the hydrogen storage system. P pem This represents the output power of the electrolytic cell.

[0015] Furthermore, the new energy microgrid includes a photovoltaic system, a hydrogen storage system, and a proton exchange membrane electrolyzer, all of which are connected to a DC bus.

[0016] Furthermore, the conductivity and flow rate of the water introduced into the anode are consistent with those of the water in the actual new energy microgrid, the aging test temperature and pressure differ from those in the actual new energy microgrid by ±30%, and the current density changes from 0 to the rated current density.

[0017] Furthermore, the temperature and pressure of each group of electrolyzers under each fluctuating operating condition are set to be completely equal and constant. The current density under stable operating conditions and frequent start-stop operating conditions is a constant rated current density, while the current density under overload operating conditions and large load variation operating conditions changes periodically.

[0018] Furthermore, under overload conditions, the current density is cycled in 30-60 minute intervals. During each cycle, the current density is maintained at the rated current density for 10-30 minutes, and then operated at 1.2-1.5 times the rated value for 10-30 minutes.

[0019] Furthermore, under large load variations, the current density is cycled every 30 to 60 minutes. During the cycle, the current density is maintained at the rated value for 10 to 20 minutes, then gradually decreases to 0.2 times the rated value, and then gradually increases back to the rated value.

[0020] Furthermore, in frequent start-stop conditions, during the start-up phase, the time for the current density to rise from 0 to the rated current density is 9-11 seconds; during the stop phase, the time for the current density to drop from the rated current density to 0 is 9-11 seconds.

[0021] Furthermore, the two groups of electrolyzers to be tested were divided into a control group and an experimental group. The control group ran continuously for 250-350 hours, while the experimental group underwent multiple consecutive start-up and shutdown operations within the 250-350 hours, with each start-up and shutdown operation spaced 15-25 hours apart. This invention can determine the aging status by measuring physical indicators such as the input voltage of the proton exchange membrane electrolyzer.

[0022] The beneficial effects of this invention are as follows: Through multi-condition coupling, this invention can simultaneously acquire degradation data of key components such as membranes, catalyst layers, and bipolar plates, enabling a comprehensive assessment of the overall lifespan of the electrolyzer; through dynamic condition combinations, the aging test cycle is shortened to 1 / 10 to 1 / 5, improving aging efficiency; by setting up multiple sets of synchronous comparative experiments, controlling parameters such as temperature, pressure, and current density in groups, and synchronously simulating aging paths under different conditions, this invention reveals the correlation between overall performance degradation and component aging, providing theoretical support for the macroscopic operating voltage and microscopic component performance degradation patterns, thereby improving overall stack lifespan and reducing material costs. Attached Figure Description

[0023] Figure 1 This is a flowchart of the aging test method for the electro-hydrogen production system of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the new energy microgrid of the present invention;

[0025] Figure 3 This is a schematic diagram illustrating the four fluctuating operating conditions of the present invention;

[0026] Figure 4 This is a flowchart of the aging test experiment of the present invention;

[0027] Figure 5 The graph shows the membrane conductivity decay results under different operating conditions in a specific embodiment of the present invention.

[0028] Figure 6 This is a diagram showing the porosity decay results of the diffusion layer under different operating conditions in a specific embodiment of the present invention;

[0029] Figure 7 The diagram shows the attenuation results of bipolar plate contact resistance under different operating conditions in a specific embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some examples of this invention, and not all examples. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0031] Example 1

[0032] This embodiment provides an aging test method for an electric hydrogen production system simulating fluctuating operating conditions of a new energy microgrid, such as... Figure 1 As shown, it includes: S1, establishing a new energy microgrid model; S2, setting constraints for the new energy microgrid model and dividing it into fluctuating operating conditions; S3, selecting multiple identical proton exchange membrane electrolyzers into groups, and making each group of electrolyzers operate synchronously under different fluctuating operating conditions; S4, conducting multiple comparative experiments.

[0033] S1. Establish a new energy microgrid model: Establish a new energy microgrid model consisting of a photovoltaic system model, a hydrogen storage system model, and a proton exchange membrane electrolyzer model, and solve for the maximum power of the grid load. P nmax Maximum power generation of photovoltaic system P pmax Hydrogen storage system capacity E h Maximum operating power of hydrogen storage system P hmax Output power of the electrolytic cell P pem .

[0034] By collecting the maximum power point current under the operating conditions of the photovoltaic system I mp and the maximum power point voltage under operating conditions V mp Determine the maximum power generation of the photovoltaic system. P pmax .

[0035] The new energy microgrid consists of a photovoltaic system, a proton exchange membrane electrolyzer, and a hydrogen storage system, all connected by a DC bus. The structure of the new energy microgrid is as follows: Figure 2 As shown.

[0036] The key components of a proton exchange membrane electrolyzer are the proton exchange membrane, anode and cathode catalyst layers, anode and cathode gas diffusion layers, and anode and cathode bipolar plates. The proton exchange membrane is a Nafion perfluorosulfonic acid membrane, composed of perfluorosulfonic acid resin with a hydrophobic polytetrafluoroethylene (PTFE) framework. The anode and cathode gas diffusion layers are made of a double-layer carbon-based porous material, consisting of a macroporous carbon paper or carbon cloth substrate and a microporous layer formed on its surface by carbon powder and a hydrophobic agent. The main components of the anode and cathode catalyst layers are catalysts, supports, and proton-conducting ionomers. The cathode catalyst layer has a Pt / C structure, with carbon materials as the main support. The anode catalyst is IrO2, and the anode and cathode bipolar plates are made of carbon-polymer composite materials. The geometric parameters of the proton exchange membrane electrolyzer are shown in Table 1.

[0037] Table 1 Geometric parameters of proton exchange membrane electrolyzer

[0038]

[0039] A photovoltaic system consists of multiple independent photovoltaic modules connected in series or parallel. Each photovoltaic module comprises a current source, a diode, and a loss impedance. A hydrogen storage system consists of hydrogen storage equipment, an integrated pressure regulation module, and a hydrogen storage system controller.

[0040] S2. Set the constraints for the new energy microgrid model and divide it into fluctuating operating conditions, such as... Figure 3 As shown.

[0041] Fluctuating operating conditions are classified into stable operating conditions, overload operating conditions, frequent start-stop operating conditions, and large load variation operating conditions.

[0042] Stable operating conditions: P pmax ≥ P nmax 20% < E h With a power consumption of ≤80%, the photovoltaic system power exceeds the grid load power, the hydrogen storage equipment (i.e., hydrogen storage tank) is within the normal range, and the electrolyzer operates normally in order to consume the excess power.

[0043] Overload conditions: P pmax ≥ P nmax , E h When the percentage is ≤20%, the photovoltaic system power is greater than the grid load power, and the hydrogen storage equipment is in a low saturation state. In order to accelerate the hydrogen storage and consume the excess power, the electrolyzer operates at a higher power.

[0044] Significant load variation conditions, including significant loading and significant unloading conditions: P pmax ≥P nmax , E h % > 80%.

[0045] Frequent start-stop conditions: P pmax < P nmax , E h If the hydrogen content is ≤20%, the electrolyzer needs to be started up quickly to consume excess power and ensure the hydrogen capacity in the storage tank. P pmax < P nmax 20% < E h If the percentage is ≤80%, there is no excess power in the power grid, and the electrolytic cell needs to be stopped. P pmax < P nmax , E h If the hydrogen content is greater than 80%, there is excess power in the power grid, but the hydrogen storage capacity inside the hydrogen storage tank is about to exceed saturation, so the electrolyzer needs to be stopped.

[0046] S3. Select multiple identical proton exchange membrane electrolyzers and group them into groups, and then operate each group of electrolyzers synchronously under different fluctuating operating conditions. Specifically, select multiple identical proton exchange membrane electrolyzers and divide these devices into four groups. Pass water into their anodes and set different current densities so that each group of electrolyzers operates synchronously under different fluctuating operating conditions.

[0047] Specifically, the conductivity and flow rate of the water introduced into the anode are consistent with those of the water in the actual new energy microgrid, the aging test temperature and pressure differ from those in the actual new energy microgrid by ±30%, and the current density changes from 0 to the rated current density.

[0048] Specifically, the temperature and pressure of each group of electrolyzers under each fluctuating operating condition are set to be completely equal and constant. The current density under stable operating conditions and frequent start-stop operating conditions is a constant rated current density, while the current density under overload operating conditions and large load variation operating conditions changes periodically.

[0049] Specifically, under overload conditions, the current density is cycled in 30-60 minutes. During the cycle, the current density is maintained at the rated current density for 10-30 minutes, and then operated at 1.2-1.5 times the rated value for 10-30 minutes.

[0050] Specifically, under large load variations, the current density is cycled in 30-60 minute intervals. During each cycle, the current density is maintained at the rated value for 10-20 minutes, then gradually decreases to 0.2 times the rated value, and then gradually increases back to the rated value.

[0051] Specifically, in frequent start-stop conditions, during the start-up phase, the time for the current density to rise from 0 to the rated current density is 9-11 seconds; during the stop phase, the time for the current density to drop from the rated current density to 0 is 9-11 seconds.

[0052] S4. Conduct multiple control experiments: At equal intervals, stop some of the electrolytic cells in each group and repeat this process several times to obtain electrolytic cells with different operating times. Then, remove the key components from these electrolytic cells and analyze the impact of different conditions at different times on the performance aging of the key components.

[0053] The following provides a detailed explanation of steps S3 and S4 using specific data, and the aging test procedure is as follows: Figure 4 As shown.

[0054] 1) Select 60-140 monomers from the electrolytic cells and divide them into 4 experimental groups, with each experimental group containing 15-35 monomers. Within each experimental group, further divide them into 3-7 control groups, with each control group containing 5 monomers.

[0055] 2) Set experimental parameters:

[0056] Stable operating conditions: The set temperature is constant at 60℃, the gas pressure is constant at 1000kPa, and the current density is constant at the rated current density;

[0057] Overload condition: Set the temperature to a constant 60℃, the gas pressure to a constant 1000kPa, and the current density to change periodically, with a minimum cycle of 30min. During this cycle, the current density is maintained at the rated current density for 15min~20min, and then the current density is maintained at 1.2 times the rated current density for 10min~15min.

[0058] Large load variation condition: The temperature is set to a constant 60℃, the gas pressure is set to a constant 1000kPa, and the current density changes periodically with a minimum cycle of 30min. The current density is maintained at the rated current density for 15min~20min, and then the current density changes stepwise to 0.8 times, 0.6 times, 0.4 times, 0.2 times, 0.4 times, 0.6 times, and 0.8 times the rated current density. The current density is maintained at 0.2 times the rated current density for about 4min~9min, and at 0.4 times, 0.6 times, and 0.8 times the rated current density for about 1min.

[0059] Frequent start-stop conditions: Set the temperature and gas pressure to remain constant. During the cycle, the temperature is 60℃ and the gas pressure is 1000kPa. During the start-up phase, the time for the current density to rise from 0 to the rated current density is 10s. During the stop phase, the time for the current density to drop from the rated current density to 0 is 10s.

[0060] 3) Water is introduced into the anodes of each group of electrolytic cells, and the starting conditions are set to start each group of electrolytic cells simultaneously;

[0061] 4) Repeat the start-up, running, and stopping phases 5-7 times;

[0062] 5) Measure the output voltage of the electrolytic cell.

[0063] Through multiple sets of synchronous experiments, this invention accurately captures the performance degradation law of key components under different working conditions. The quantification of the degradation of key components is shown in Table 2.

[0064] Table 2 Quantification of Attenuation Rate of Key Components

[0065]

[0066] Proton exchange membrane conductivity decay:

[0067] Frequent start-stop conditions: conductivity decreases at a rate of 0.8% / h. Figure 5 The percentage was significantly higher than the 0.1% / h under stable operating conditions, proving that start-stop impacts accelerate membrane structure degradation.

[0068] Overload conditions: The superposition of high temperature (80℃) and high current density (1.5 times the rated value) results in a conductivity decay rate of 1.2% / h, providing key data for optimizing high temperature resistant membrane materials.

[0069] The porosity of the gas diffusion layer decreases:

[0070] The porosity increased by 0.41% within 300 hours under rapid and large load changes. Figure 6 The increase was only 0.02% under stable operating conditions, indicating that dynamic load changes exacerbate the mechanical fatigue of carbon-based materials.

[0071] Bipolar plate contact resistance increases:

[0072] Overload condition: Contact resistance increases by 18% ( Figure 7 The current density is far greater than 3% under stable operating conditions, highlighting the corrosive effect of high current density on carbon-polymer composite materials.

[0073] Table 3 shows a comparison between traditional static testing and the dynamic testing of the present invention on the same electro-hydrogen production equipment. The dynamic testing method of the present invention is 10 times more efficient than the traditional static testing method.

[0074] Table 3 Comparison of Accelerated Aging Efficiency

[0075]

[0076] In this embodiment, the experimental data is compared with the disassembly and testing results of an actual microgrid electrolyzer (operated for 6 months), showing that:

[0077] Membrane conductivity decay: The simulated decay value after 6 months was 15%, while the actual measured value was 14.5%, with an error of only 3.4%.

[0078] Porosity of the diffusion layer: 18% in experimental simulation, 17% in actual value, with an error of 5.8%.

[0079] This invention can predict the lifespan of components in actual operation with high accuracy (error <6%) through dynamic operating condition simulation, providing a reliable basis for operation and maintenance strategies.

[0080] In this embodiment, to address potential water quality fluctuations in a real microgrid, the present invention verifies the method's adaptability by adjusting the anode feed water parameters. Under low conductivity water (0.5 μS / cm), the membrane conductivity decay rate increases by 12%, indicating that a reduction in impurity ions may exacerbate the membrane dehydration effect. At high flow rates (5.0 ml / (min·cm)... 2 Under operating conditions, the rate of decrease in diffusion layer porosity is reduced by 8%, as the high flow rate mitigates localized corrosion caused by bubble retention. This invention, by controlling influent parameters, can simulate different water quality conditions, providing customized testing solutions for microgrid site selection (such as in areas with poor water quality).

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aging test method for an electric hydrogen production system simulating fluctuating operating conditions of a new energy microgrid, characterized in that, include: Multiple identical proton exchange membrane electrolyzers were selected and divided into four groups. Water was introduced into their anodes, and different current densities were set so that each group of electrolyzers operated synchronously under different fluctuating conditions. The fluctuating conditions were stable conditions, overload conditions, frequent start-stop conditions, and large load variation conditions. At equal intervals, some electrolytic cells in each group were stopped from operating, and this process was repeated several times to obtain electrolytic cells with different operating times. Then, the key components in these electrolytic cells were removed, and the effects of different conditions at different times on the performance aging of the key components were analyzed.

2. The aging test method for the electro-hydrogen production system according to claim 1, characterized in that, The stable operating condition is as follows: when the photovoltaic system power is within the range that the grid load can withstand, the hydrogen storage system has not reached saturation, and the electrolyzer operates at normal power. The overload condition is as follows: when the photovoltaic system power exceeds the range that the grid load can withstand, and the hydrogen storage system has not reached saturation, the electrolyzer operates beyond its rated load. The large load change condition is as follows: when the photovoltaic system power is about to exceed the range that the grid load can withstand, and the hydrogen storage system is about to reach saturation, the electrolyzer changes its load in stages at its rated power. The frequent start-stop condition is as follows: when the photovoltaic system power is unstable, and the hydrogen storage system reaches saturation, the electrolyzer needs to be frequently started and stopped to stabilize the grid load, and the electrolyzer operates at a constant rated current density.

3. The aging test method for the electro-hydrogen production system according to claim 2, characterized in that, The constraints for the fluctuating operating condition are as follows: The aforementioned stable operating condition: P pmax ≥ P nmax 20% < E h %≤80%; The overload condition described: P pmax ≥ P nmax , E h %≤20%; The aforementioned large load variation conditions: P pmax ≥ P nmax , E h % > 80%; The aforementioned frequent start-stop conditions: P pmax < P nmax , E h %≤20%, rapid start-up of the electrolytic cell; P pmax < P nmax 20% < E h %, the electrolytic cell stopped working; in, P nmax This represents the maximum power of the power grid load. P pmax This represents the maximum power generation capacity of the photovoltaic system. E h For the capacity of the hydrogen storage system, P hmax This represents the maximum operating power of the hydrogen storage system. P pem This represents the output power of the electrolytic cell.

4. The aging test method for the electro-hydrogen production system according to claim 1, characterized in that, The new energy microgrid includes a photovoltaic system, a hydrogen storage system, and a proton exchange membrane electrolyzer, all of which are connected to a DC bus.

5. The aging test method for the electro-hydrogen production system according to claim 1, characterized in that, The conductivity and flow rate of the water introduced into the anode are consistent with those of the water in the actual new energy microgrid. The aging test temperature and pressure differ from those in the actual new energy microgrid by ±30%, and the current density changes from 0 to the rated current density.

6. The aging test method for the electro-hydrogen production system according to claim 1, characterized in that, The temperature and pressure of each group of electrolyzers under each fluctuating operating condition are set to be completely equal and constant. The current density under stable operating conditions and frequent start-stop operating conditions is a constant rated current density, while the current density under overload operating conditions and large load variation operating conditions changes periodically.

7. The aging test method for the electro-hydrogen production system according to claim 6, characterized in that, Under overload conditions, the current density is cycled in 30-60 minutes. During the cycle, the current density is maintained at the rated current density for 10-30 minutes, and then operated at 1.2-1.5 times the rated value for 10-30 minutes.

8. The aging test method for the electro-hydrogen production system according to claim 6, characterized in that, Under large load variations, the current density is cycled every 30 to 60 minutes. During the cycle, the current density is maintained at the rated value for 10 to 20 minutes, then gradually decreased to 0.2 times the rated value, and then gradually increased back to the rated value.

9. The aging test method for the electro-hydrogen production system according to claim 6, characterized in that, In frequent start-stop conditions, during the start-up phase, the time for the current density to rise from 0 to the rated current density is 9-11 seconds; during the stop phase, the time for the current density to drop from the rated current density to 0 is 9-11 seconds.

10. The aging test method for the electro-hydrogen production system according to claim 6, characterized in that, The two groups of electrolytic cells to be tested were divided into a control group and an experimental group. The control group ran continuously for 250-350 hours, while the experimental group underwent multiple start-up and shutdown operations within 250-350 hours, with an interval of 15-25 hours between each start-up and shutdown operation.

Images