A method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance

Abstract

The application relates to a kind of proton exchange membrane electrolytic cell internal temperature measuring methods based on EIS impedance, the EIS impedance parameter in the proton exchange membrane electrolytic cell is simulated by external numerical simulation analysis software, three-dimensional thermal model is established, the relationship between the EIS impedance parameter and internal temperature of the proton exchange membrane electrolytic cell is obtained, and then the internal temperature of the corresponding position of the proton exchange membrane electrolytic cell is obtained.Compared with the prior art, the application has higher accuracy, lower cost, simpler and more compact structure, no pollution, no need to break the electrolytic cell structure to measure the internal temperature of the electrolytic cell, and it can measure the internal temperature of each cell in the electrolytic stack, and provide temperature parameters for intelligent control and active safety control of the electrolytic cell.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production by water electrolysis, and in particular to a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance. Background Technology

[0002] Currently, hydrogen energy has become a clean energy carrier supporting the development of new power systems, and hydrogen production from renewable energy sources is one of the best solutions. Proton exchange membrane electrolyzers can adapt to the intermittent and fluctuating nature of renewable energy power generation, demonstrating enormous application potential and representing an important direction for achieving sustainable energy development in the future. During the operation of the electrolyzer, changes in temperature and physical properties affect the performance of key components such as the membrane electrode assembly (MEA), thus impacting the electrolyzer's efficiency and lifespan. Furthermore, large-scale water electrolysis for hydrogen production generates significant heat, which must be transferred through the electrolyzer. This necessitates thermal management of the electrolyzer, making internal temperature measurement crucial for effective thermal management.

[0003] Currently, the commonly used methods for measuring the temperature of electrolytic cells are thermocouples and resistance temperature detectors (RTDs). These two methods mostly measure from outside the electrolytic cell and can only measure a limited area. Due to the thermal inertia of the electrolytic cell, there is a significant time delay between the surface temperature signal and the internal temperature signal, resulting in a considerable temperature difference between the outer surface and the interior, making it difficult to obtain the internal temperature. Numerical models can be used to estimate the internal temperature of the electrolytic cell, but the accuracy of the simulation depends on the complexity of the underlying model, and the simulation time is also long. If distributed fiber optic sensors are installed inside the electrolytic cell, internal temperature information can be obtained, but this requires modifying the internal structure of the electrolytic cell, and the fiber optic measuring device and its installation are relatively complex. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, which can accurately estimate the internal temperature of the electrolyzer online without damaging the internal structure of the proton exchange membrane electrolyzer.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance includes the following steps:

[0007] A1: Set the water temperature inside the proton exchange membrane electrolyzer to simulate the water circulation during the operation of the proton exchange membrane electrolyzer. When the proton exchange membrane electrolyzer and the water circulation reach thermal equilibrium, connect an EIS impedance measuring instrument to obtain the EIS impedance parameters of the proton exchange membrane electrolyzer at that temperature.

[0008] A2: Referring to step A1, obtain the EIS impedance parameters in the proton exchange membrane electrolyzer at different temperatures;

[0009] A3: Input the EIS impedance parameters obtained in step A2 into external numerical simulation analysis software, set the same working conditions for simulation, establish a three-dimensional thermal model, obtain the temperature at different locations inside the proton exchange membrane electrolyzer, and then simulate multiple working conditions to obtain the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer, and input it into the temperature analyzer.

[0010] A4: Replace the water in the proton exchange membrane electrolyzer with electrolyte, turn on the proton exchange membrane electrolyzer for normal operation, use the EIS impedance meter to detect the EIS impedance parameters under the current operating conditions, input the data into the temperature analyzer, and obtain the internal temperature of the corresponding position of the proton exchange membrane electrolyzer according to the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer in step A3.

[0011] Furthermore, in step A1, the proton exchange membrane electrolyzer is set to a constant temperature water tank; and a circulating water pump is connected to simulate the water circulation during the operation of the proton exchange membrane electrolyzer.

[0012] Furthermore, the circulating water pump is equipped with a flow control component to regulate the water flow rate and simulate the electrolyte flow in the proton exchange membrane electrolyzer under different operating conditions.

[0013] Furthermore, the constant temperature water tank contains an intelligent water temperature control component, which can provide a water source with a constant temperature for the proton exchange membrane electrolyzer.

[0014] Further, in step A1, the EIS impedance measuring instrument includes a power excitation module and an impedance calculation module. The power excitation module is used to generate a DC load current and an AC excitation current, both of which are applied to the proton exchange membrane electrolyzer; the impedance calculation module performs EIS impedance calculation based on the collected current and voltage data.

[0015] Further, in step A1, the EIS impedance parameters include the EIS impedance magnitude, EIS phase angle, real part of impedance, imaginary part of impedance, and parameters obtained by data processing using impedance, such as capacitance or resistance in the equivalent circuit method.

[0016] Furthermore, in step A3, the specific operation process for establishing the three-dimensional thermal model is as follows:

[0017] B1: Establish a three-dimensional model of each component of the proton exchange membrane electrolyzer in the numerical simulation analysis software. First, import the geometric model of the proton exchange membrane electrolyzer into the simulation software or establish the geometric model of the proton exchange membrane electrolyzer in the simulation software. Set the physicochemical parameters of each module in the geometric model. After setting, divide the geometric model into meshes and establish a three-dimensional simulation model.

[0018] B2: Select a certain working condition for simulation, calculate the temperature at a certain position on the inner surface of the proton exchange membrane electrolyzer, and compare it with the experimental measurement value to determine the accuracy of the three-dimensional thermal model. If the accuracy meets the requirements, the three-dimensional thermal model is established; otherwise, return to step B1 to modify the model parameters of the three-dimensional simulation model.

[0019] Further, in step B1, the geometric model of the proton exchange membrane electrolyzer includes: an anode plate module, an oxygen chamber module, an anode diffusion layer module, a catalyst coating membrane module, a cathode diffusion layer module, a hydrogen chamber module, and a cathode plate module.

[0020] Furthermore, the physicochemical parameters of each module within the geometric model specifically include: selecting heat-generating elements, setting physical fields, setting the heating power of the heat-generating elements, the specific heat capacity, thermal conductivity, and convective heat transfer coefficient of the heat transfer elements, setting the conductivity of the electrodes, setting the diffusion coefficient and flow rate of the electrolyte, and setting boundary conditions.

[0021] Furthermore, the heat-generating element is a catalyst-coated film, including a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

[0022] Furthermore, the calculation formulas for heat generation and heat transfer of each module within the geometric model are as follows:

[0023]

[0024] q c =h(T) h -T l )

[0025]

[0026] Where, q r The heat flux density representing heat conduction, q c The heat flux density represents heat convection, k represents thermal conductivity, h represents convective heat transfer coefficient, and T represents heat flux density. h T represents a higher temperature. l Representing a lower temperature, q represents the heat flux density of thermal radiation, σ represents the blackbody radiation constant, δ represents the emissivity, and T a T represents the absolute temperature of the first radiating surface. bThis represents the absolute temperature of the second radiating surface.

[0027] Furthermore, the kinetics of the electrode reaction within the geometric model are governed by the Butler-Volmer equation, calculated as follows:

[0028]

[0029]

[0030] Among them, i a α represents the current density of the anode electrode. V，a i represents the specific surface area of ​​the anode gas diffusion electrode. o，a The exchange current density representing the anodic electrochemical reaction, α a The charge transfer coefficient of the anode is represented by F, and F represents the Faraday constant, η. act，a R represents the over-point potential of the anodic reaction, R represents the gas constant, and T represents the thermodynamic temperature.

[0031] i c α represents the current density of the cathode electrode. V，c i represents the specific surface area of ​​the cathode gas diffusion electrode. o，c The exchange current density representing the cathodic electrochemical reaction, α c η represents the charge transfer coefficient of the cathode. act，c This represents the over-point of the cathode reaction.

[0032] Furthermore, the flow of liquid and gas in the geometric model is calculated using the continuity equation, the Navier-Stokes equation, and the total energy equation, as shown in the following formulas:

[0033]

[0034]

[0035]

[0036] Where ρ represents fluid density and t represents time. Represents the partial differential operator, u represents the fluid velocity, p represents the fluid pressure, τ represents the fluid stress tensor, g represents the gravitational acceleration, and C represents the partial differential operator. V represents specific heat capacity, T represents the temperature of the fluid, k represents the thermal conductivity, and Q represents the heat source per unit volume per unit time.

[0037] Furthermore, in step B2, if the accuracy reaches within 5%, the three-dimensional thermal model is established; otherwise, return to step B1 to modify the model parameters of the three-dimensional model.

[0038] Further, in step A3, the internal temperature is the temperature at a certain location inside the proton exchange membrane electrolyzer, including the highest temperature, the lowest temperature, and the average temperature.

[0039] Furthermore, in step A3, the relationship between the EIS impedance parameter and the internal temperature of the proton exchange membrane electrolyzer is a functional relationship or a lookup table; if it is a functional relationship, it is expressed as: T = f(a, b, c, ...), where T is the internal temperature of the proton exchange membrane electrolyzer, and a, b, c, ... are the EIS impedance parameters; if it is a lookup table, the internal temperature of the proton exchange membrane electrolyzer can be obtained by looking up the table. The three-dimensional simulation model can analyze the temperature distribution inside the proton exchange membrane electrolyzer, and can also plot the electrochemical impedance spectrum of the electrolyzer under corresponding operating conditions, which can then be used to deduce the relationship between the electrochemical impedance spectrum and the internal temperature of the electrolyzer.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) This invention does not require the implantation of sensors inside the electrolyzer, and will not damage the internal structure of the proton exchange membrane water electrolyzer. It only requires the use of an external electrolyzer EIS impedance measuring instrument to measure parameters such as voltage and current of the electrolyzer, calculate the EIS impedance, and transmit the impedance information to the internal temperature analyzer of the electrolyzer. The analyzer can quickly estimate the required internal temperature of the electrolyzer based on the established correspondence between the electrolyzer impedance and the internal temperature of the electrolyzer.

[0042] (2) The three-dimensional thermal model established by the present invention can calculate the temperature field of the entire electrolytic cell and obtain the temperature distribution inside the electrolytic cell. Temperature measurement points can be selected according to actual engineering needs to monitor the local temperature inside the electrolytic cell, obtain the average temperature, and evaluate the temperature consistency inside the electrolytic cell.

[0043] (3) Based on the established relationship between the impedance and internal temperature of the electrolytic cell, this invention can quickly and relatively accurately estimate the internal temperature information of the electrolytic cell, providing temperature parameters for intelligent management and active safety control of the electrolytic cell, and improving the safety of the electrolytic cell. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of Example 1;

[0045] For clarity, Figure 1 In the EIS impedance measuring instrument, the power excitation module and impedance calculation module are represented separately; however, in actual instruments, the two modules are integrated into the same chassis.

[0046] Figure 2 This is a flowchart illustrating the process of establishing a three-dimensional thermal model using numerical simulation analysis software in Example 1.

[0047] Figure 3 The circuit diagram of the second-order RC equivalent circuit of the electrolytic cell in Example 1 is shown.

[0048] Figure 4 The impedance curves of the electrolytic cell at different temperatures in Example 1 are shown.

[0049] Figure 5 This is a geometric model diagram of the proton exchange membrane electrolyzer shown in Example 1.

[0050] Explanation of markings in the diagram:

[0051] 1-Anode plate module, 2-Anode diffusion layer module, 3-Catalyst coating film module, 4-Cathode diffusion layer module, 5-Cathode plate module. Detailed Implementation

[0052] To make the objectives, technical solutions, and innovations of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0053] Example 1

[0054] See Figure 1 and Figure 2 This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance. This method can accurately estimate the internal temperature of the electrolyzer online without damaging its internal structure. The method includes the following steps:

[0055] A1: Set the water temperature inside the proton exchange membrane electrolyzer to 60℃ to simulate the water circulation during operation. Once the proton exchange membrane electrolyzer and water circulation reach thermal equilibrium, connect an EIS impedance meter to obtain the EIS impedance of the proton exchange membrane electrolyzer at that temperature. Figure 3 As shown, by using impedance data over a wide frequency range, a second-order RC equivalent circuit model can be established to obtain the specific values ​​of R and C in the equivalent circuit and quantitatively describe the impedance parameters.

[0056] A2: Referring to step A1, the EIS impedance in the proton exchange membrane electrolyzer at 70℃ and 80℃ is obtained, and the corresponding equivalent circuit model parameters can be acquired. For example... Figure 4 As shown in Table 1, the impedance curves of the electrolytic cell at different temperatures were obtained. The parameters of the second-order RC equivalent circuit model of the electrolytic cell at different temperatures were then compiled.

[0057] Table 1. Parameters of the second-order RC equivalent circuit at different temperatures

[0058]

[0059] A3: Input the EIS impedance parameters obtained in step A2 into external numerical simulation analysis software, set the same working conditions for simulation, establish a three-dimensional thermal model, obtain the temperature at different locations inside the proton exchange membrane electrolyzer, and then simulate multiple working conditions to obtain the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer, and input it into the temperature analyzer.

[0060] A4: Replace the water in the proton exchange membrane electrolyzer with electrolyte, turn on the proton exchange membrane electrolyzer for normal operation, use the EIS impedance meter to detect the EIS impedance parameters under the current operating conditions, input the data into the temperature analyzer, and obtain the average internal temperature T of the proton exchange membrane electrolyzer based on the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer in step A3. in .

[0061] In this embodiment, in step A1, the proton exchange membrane electrolyzer is set to a constant temperature water tank; a circulating water pump is connected to simulate the water circulation during operation of the proton exchange membrane electrolyzer. The circulating water pump is equipped with a flow control component to adjust the water flow rate and simulate the electrolyte flow in the proton exchange membrane electrolyzer under different operating conditions. The constant temperature water tank contains an intelligent water temperature control component, which can provide a constant temperature water source for the proton exchange membrane electrolyzer.

[0062] In this embodiment, in step A1, the EIS impedance measuring instrument includes a power excitation module and an impedance calculation module. The power excitation module generates a DC load current and an AC excitation current, both of which are applied to the proton exchange membrane electrolyzer. The impedance calculation module performs EIS impedance calculation based on the collected current and voltage data. In this embodiment, the EIS impedance parameter is the resistance R in the equivalent circuit method. P1 .

[0063] In this embodiment, the specific operation process of establishing the three-dimensional thermal model in step A3 is as follows, see below. Figure 2 As shown:

[0064] B1: Establish a three-dimensional model of each component of the proton exchange membrane electrolyzer in the numerical simulation analysis software, see [link to relevant documentation]. Figure 5First, the geometric model of the proton exchange membrane electrolyzer is imported into the simulation software or the geometric model of the proton exchange membrane electrolyzer is established in the simulation software. The physicochemical parameters of each module in the geometric model are set. After the setting is completed, the geometric model is divided into meshes to establish a three-dimensional simulation model.

[0065] B2: Select three sets of operating conditions for simulation. The calculated average surface temperatures of the proton exchange membrane electrolyzer are 30.17℃, 39.85℃, and 51.63℃, respectively. Compare these with the experimental measurements of 29.31℃, 40.63℃, and 50.23℃. The errors are 2.93%, 1.92%, and 2.79%, respectively, all less than 5%, indicating that the accuracy meets the requirements. The three-dimensional thermal model is now complete. If the accuracy does not meet the requirements, return to step B1 to modify the model parameters of the three-dimensional model.

[0066] In this embodiment, in step B1, the geometric model of the proton exchange membrane electrolyzer includes: an anode plate module 1, an oxygen chamber module, an anode diffusion layer module 2, a catalyst coating membrane module 3, a cathode diffusion layer module 4, a hydrogen chamber module, and a cathode plate module 5. Setting the physicochemical parameters of each module within the geometric model specifically includes: selecting heat-generating elements, setting the physical field, setting the heating power of the heat-generating elements, the specific heat capacity, thermal conductivity, and convective heat transfer coefficient of the heat transfer elements, setting the conductivity of the electrodes, setting the diffusion coefficient and flow rate of the electrolyte, and setting boundary conditions. The heat-generating elements are mainly catalyst coating membranes, including a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

[0067] In this embodiment, in the electrolytic cell, the cathode and anode catalysts are coated on both sides of the proton exchange membrane to form a catalyst-coated membrane. The main thermal conductivity exists between the catalyst-coated membrane and the diffusion layers on both sides; the main thermal conductivity and convection exist between the diffusion layers and the fluid; the main thermal conductivity and convection exist between the fluid and the electrode plates; and the main thermal convection and radiation exist between the electrode plates and the outside air. The calculation formula is shown below.

[0068]

[0069] q c =h(T) h -T l )

[0070]

[0071] Where, q r The heat flux density representing heat conduction, q c The heat flux density represents heat convection, k represents thermal conductivity, h represents convective heat transfer coefficient, and T represents heat flux density. h T represents a higher temperature. lRepresenting a lower temperature, q represents the heat flux density of thermal radiation, σ represents the blackbody radiation constant, δ represents the emissivity, and T a T represents the absolute temperature of the first radiating surface. b This represents the absolute temperature of the second radiating surface.

[0072] The kinetics of the electrode reaction are controlled by the Butler-Volmer equation.

[0073]

[0074]

[0075] Among them, i a α represents the current density of the anode electrode. V,a i represents the specific surface area of ​​the anode gas diffusion electrode. o,a The exchange current density representing the anodic electrochemical reaction, α a The charge transfer coefficient of the anode is represented by F, and F represents the Faraday constant, η. act,a R represents the over-point potential of the anodic reaction, R represents the gas constant, and T represents the thermodynamic temperature.

[0076] i c α represents the current density of the cathode electrode. V,c i represents the specific surface area of ​​the cathode gas diffusion electrode. o,c The exchange current density representing the cathodic electrochemical reaction, α c η represents the charge transfer coefficient of the cathode. act,c This represents the over-point of the cathode reaction.

[0077] The flow of liquids and gases in an electrolyzer can be described using the continuity equation, the Navier-Stokes equation, and the total energy equation.

[0078]

[0079]

[0080]

[0081] Where ρ represents fluid density and t represents time. Represents the partial differential operator, u represents the fluid velocity, p represents the fluid pressure, τ represents the fluid stress tensor, g represents the gravitational acceleration, and C represents the partial differential operator. V represents specific heat capacity, T represents the temperature of the fluid, k represents the thermal conductivity, and Q represents the heat source per unit volume per unit time.

[0082] In this embodiment, in step B1, the components of the proton exchange membrane electrolyzer include an electrode plate, an anode diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, and a cathode diffusion layer; the heat-generating element is mainly a catalyst-coated membrane; the catalyst-coated membrane includes a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

[0083] In this embodiment, in step A3, the equivalent circuit model parameter R P1 and internal temperature T in The relationship between them is a functional relationship, expressed as: T in =-0.027R P1 2 +186.22R P1 -127.21, where T in R is the internal temperature of the proton exchange membrane electrolyzer. P1 The values ​​of the selected resistance parameters in the equivalent circuit model are multiplied by 10. 3 .

[0084] In this embodiment, in step A4, the temperature analyzer can analyze and calculate the internal temperature based on the detected EIS impedance characteristic parameters and the relationship between the existing EIS impedance parameters and the internal temperature. Using an electrolyte at 55°C to simulate the operation of an electrolytic cell, the internal temperature can be measured as 55.31°C, and the calculation result is relatively accurate.

[0085] Example 2

[0086] See Figure 1 and Figure 2 This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance. This method can accurately estimate the internal temperature of the electrolyzer online without damaging its internal structure. The method includes the following steps:

[0087] A1: Set the water temperature inside the proton exchange membrane electrolyzer to 60℃ to simulate the water circulation during the operation of the proton exchange membrane electrolyzer. When the proton exchange membrane electrolyzer and the water circulation reach thermal equilibrium, connect an EIS impedance measuring instrument to obtain the EIS impedance of the proton exchange membrane electrolyzer at this temperature.

[0088] A2: Referring to step A1, obtain the EIS impedance in the proton exchange membrane electrolyzer at 70℃ and 80℃. For example... Figure 4 As shown in Table 2, the impedance curves of the electrolytic cell at different temperatures were obtained. The real part data of the impedance at a selected frequency point (0.126Hz in this example) at different temperatures were then obtained.

[0089] Table 2 Real part of impedance at 0.126Hz at different temperatures

[0090] Water temperature / ℃ 60 70 80 <![CDATA[Z-real / Ω·cm 2 ]]> 0.00668 0.00645 0.00631

[0091] A3: Input the EIS impedance parameters obtained in step A2 into external numerical simulation analysis software, set the same working conditions for simulation, establish a three-dimensional thermal model, obtain the temperature at different locations inside the proton exchange membrane electrolyzer, and then simulate multiple working conditions to obtain the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer, and input it into the temperature analyzer.

[0092] A4: Replace the water in the proton exchange membrane electrolyzer with electrolyte, turn on the proton exchange membrane electrolyzer for normal operation, use the EIS impedance meter to detect the EIS impedance parameters under the current operating conditions, input the data into the temperature analyzer, and obtain the average internal temperature T of the proton exchange membrane electrolyzer based on the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer in step A3. in .

[0093] In this embodiment, in step A1, the proton exchange membrane electrolyzer is set to a constant temperature water tank; a circulating water pump is connected to simulate the water circulation during operation of the proton exchange membrane electrolyzer. The circulating water pump is equipped with a flow control component to adjust the water flow rate and simulate the electrolyte flow in the proton exchange membrane electrolyzer under different operating conditions. The constant temperature water tank contains an intelligent water temperature control component, which can provide a constant temperature water source for the proton exchange membrane electrolyzer.

[0094] In this embodiment, in step A1, the EIS impedance measuring instrument includes a power excitation module and an impedance calculation module. The power excitation module generates a DC load current and an AC excitation current, both of which are applied to the proton exchange membrane electrolyzer. The impedance calculation module performs EIS impedance calculation based on the collected current and voltage data. In this embodiment, the EIS impedance parameter is the real part of the impedance at a point at the end of the low-frequency band (0.126Hz in this example).

[0095] In this embodiment, the specific operation process of establishing the three-dimensional thermal model in step A3 is as follows, see below. Figure 2 As shown:

[0096] B1: Establish a three-dimensional model of each component of the proton exchange membrane electrolyzer in the numerical simulation analysis software, see [link to relevant documentation]. Figure 5 First, the geometric model of the proton exchange membrane electrolyzer is imported into the simulation software or the geometric model of the proton exchange membrane electrolyzer is established in the simulation software. The physicochemical parameters of each module in the geometric model are set. After the setting is completed, the geometric model is divided into meshes to establish a three-dimensional simulation model.

[0097] B2: Select three sets of operating conditions for simulation. The calculated average surface temperatures of the proton exchange membrane electrolyzer are 30.58℃, 40.12℃, and 51.34℃, respectively. Compare these with the experimental measurements of 30.13℃, 39.82℃, and 50.45℃. The errors are 1.49%, 0.75%, and 1.76%, respectively, all less than 5%, indicating that the accuracy meets the requirements. The three-dimensional thermal model is now complete. If the accuracy does not meet the requirements, return to step B1 to modify the model parameters of the three-dimensional model.

[0098] In this embodiment, in step B1, the geometric model of the proton exchange membrane electrolyzer includes: an anode plate module 1, an oxygen chamber module, an anode diffusion layer module 2, a catalyst coating membrane module 3, a cathode diffusion layer module 4, a hydrogen chamber module, and a cathode plate module 5. Setting the physicochemical parameters of each module within the geometric model specifically includes: selecting heat-generating elements, setting the physical field, setting the heating power of the heat-generating elements, the specific heat capacity, thermal conductivity, and convective heat transfer coefficient of the heat transfer elements, setting the conductivity of the electrodes, setting the diffusion coefficient and flow rate of the electrolyte, and setting boundary conditions. The heat-generating elements are mainly catalyst coating membranes, including a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

[0099] In this embodiment, in the electrolytic cell, the cathode and anode catalysts are coated on both sides of the proton exchange membrane to form a catalyst-coated membrane. The main thermal conductivity exists between the catalyst-coated membrane and the diffusion layers on both sides; the main thermal conductivity and convection exist between the diffusion layers and the fluid; the main thermal conductivity and convection exist between the fluid and the electrode plates; and the main thermal convection and radiation exist between the electrode plates and the outside air. The calculation formula is shown below.

[0100]

[0101] q c =h(T) h -T l )

[0102]

[0103] Where, q r The heat flux density representing heat conduction, q c The heat flux density represents heat convection, k represents thermal conductivity, h represents convective heat transfer coefficient, and T represents heat flux density. h T represents a higher temperature. l Representing a lower temperature, q represents the heat flux density of thermal radiation, σ represents the blackbody radiation constant, δ represents the emissivity, and T a T represents the absolute temperature of the first radiating surface. b This represents the absolute temperature of the second radiating surface.

[0104]

[0105]

[0106] Among them, i a α represents the current density of the anode electrode. V,a i represents the specific surface area of ​​the anode gas diffusion electrode. o,a The exchange current density representing the anodic electrochemical reaction, α a The charge transfer coefficient of the anode is represented by F, and F represents the Faraday constant, η. act,a R represents the over-point potential of the anodic reaction, R represents the gas constant, and T represents the thermodynamic temperature.

[0107] i c α represents the current density of the cathode electrode. V,c i represents the specific surface area of ​​the cathode gas diffusion electrode. o,c The exchange current density representing the cathodic electrochemical reaction, α c η represents the charge transfer coefficient of the cathode. act,c This represents the over-point of the cathode reaction.

[0108] The flow of liquids and gases in an electrolyzer can be described using the continuity equation, the Navier-Stokes equation, and the total energy equation.

[0109]

[0110]

[0111]

[0112] Where ρ represents fluid density and t represents time. Represents the partial differential operator, u represents the fluid velocity, p represents the fluid pressure, τ represents the fluid stress tensor, g represents the gravitational acceleration, and C represents the partial differential operator. V represents specific heat capacity, T represents the temperature of the fluid, k represents the thermal conductivity, and Q represents the heat source per unit volume per unit time.

[0113] In this embodiment, in step B1, the components of the proton exchange membrane electrolyzer include an electrode plate, an anode diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, and a cathode diffusion layer; the heat-generating element is mainly a catalyst-coated membrane; the catalyst-coated membrane includes a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

[0114] In this embodiment, in step A3, the relationship between the real part of the impedance at a certain point at the end of the low-frequency band (0.126Hz in this example) and the internal temperature is a functional relationship, expressed as: T in =75.541Z real2 -1.035Z real +3.605, where T in Z represents the internal temperature of the proton exchange membrane electrolyzer. real This is the value of the real part of the impedance at 0.126Hz in the low-frequency range, and it is multiplied by 10. 3 .

[0115] In this embodiment, in step A4, the temperature analyzer can analyze and calculate the internal temperature based on the detected EIS impedance characteristic parameters and the relationship between the existing EIS impedance parameters and the internal temperature. Using an electrolyte at 55°C to simulate the operation of an electrolytic cell, the internal temperature can be measured as 54.91°C, and the calculation result is relatively accurate.

[0116] Example 3

[0117] See Figure 1 and Figure 2 This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, which can accurately estimate the internal temperature of the electrolyzer online without damaging the internal structure of the proton exchange membrane electrolyzer.

[0118] Compared with Example 1, most of them are the same, except that in step A2, the impedance mode data of selected frequency points (5.008Hz in this example) at different temperatures are sorted out, as shown in Table 3.

[0119] Table 3 Impedance modulus at 5.008 Hz at different temperatures

[0120] Water temperature / ℃ 60 70 80 <![CDATA[Z / Ω·cm 2 ]]> 0.00617 0.00625 0.00641

[0121] Example 4

[0122] See Figure 1 and Figure 2 This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, which can accurately estimate the internal temperature of the electrolyzer online without damaging the internal structure of the proton exchange membrane electrolyzer.

[0123] Compared with Example 1, most of them are the same, except that in step A2, the impedance angle data of the selected frequency point (198.623Hz in this example) at different temperatures are collected, as shown in Table 4.

[0124] Table 4 Impedance angle at 198.623Hz at different temperatures

[0125]

[0126] Example 5

[0127] See Figure 1 and Figure 2This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, which can accurately estimate the internal temperature of the electrolyzer online without damaging the internal structure of the proton exchange membrane electrolyzer.

[0128] Compared with Example 1, most of the data are the same, except that the imaginary part of the impedance at a selected frequency point (7.945Hz in this example) at different temperatures is obtained, as shown in Table 5.

[0129] Table 5. Imaginary part of impedance at 7.945Hz at different temperatures.

[0130] Water temperature / ℃ 60 70 80 <![CDATA[Z-imag / Ω·cm 2 ]]> -0.0004176 -0.0003039 -0.0002501

[0131] Example 6

[0132] See Figure 1 and Figure 2 This embodiment provides a method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, which can accurately estimate the internal temperature of the electrolyzer online without damaging the internal structure of the proton exchange membrane electrolyzer.

[0133] Compared to Example 2, most aspects are the same, except that the EIS impedance parameter in this example is the real part of the impedance at a certain point at the end of the low-frequency band (0.159Hz in this example), and the relationship between the real part of the impedance and the internal temperature of the electrolytic cell is obtained. In step A3, since a relatively ideal functional relationship between the real part of the impedance and the internal temperature of the electrolytic cell cannot be obtained in this example, a lookup table is established, and an interpolation method is used to look up the table to estimate the internal temperature of the electrolytic cell. The lookup table of the relationship between the real part of the 0.159Hz impedance and the internal temperature of the electrolytic cell is shown in Table 6.

[0134] Table 6.0.159Hz Relationship between Real Part of Impedance and Internal Temperature of Electrolytic Cell (Lookup Table)

[0135] Water temperature / ℃ Z-real / Ω·cm2 Water temperature / ℃ Z-real / Ω·cm2 10 0.0121 50 0.00703 20 0.00906 60 0.00665 30 0.00881 70 0.00643 40 0.00811 80 0.00629

[0136] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention. It should be noted that the data given in this embodiment is only for better explanation and to make the process of this method clearer and more intuitive.

Claims

1. A method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance, characterized in that, Includes the following steps: A1: Set the water temperature inside the proton exchange membrane electrolyzer to simulate the water circulation during the operation of the proton exchange membrane electrolyzer. When the proton exchange membrane electrolyzer and the water circulation reach thermal equilibrium, connect an EIS impedance measuring instrument to obtain the EIS impedance parameters of the proton exchange membrane electrolyzer at that temperature. A2: Referring to step A1, obtain the EIS impedance parameters of the proton exchange membrane electrolyzer at different temperatures; A3: Input the EIS impedance parameters obtained in step A2 into external numerical simulation analysis software, set the same working conditions for simulation, establish a three-dimensional thermal model, obtain the temperature at different locations inside the proton exchange membrane electrolyzer, and then simulate multiple working conditions to obtain the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer, and input it into the temperature analyzer. A4: Replace the water in the proton exchange membrane electrolyzer with electrolyte, turn on the proton exchange membrane electrolyzer for normal operation, use the EIS impedance meter to detect the EIS impedance parameters under the current operating conditions, input the data into the temperature analyzer, and obtain the internal temperature of the corresponding position of the proton exchange membrane electrolyzer according to the relationship between the EIS impedance parameters and the internal temperature of the proton exchange membrane electrolyzer in step A3.

2. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 1, characterized in that, In step A1, the proton exchange membrane electrolyzer is set to a constant temperature water tank; and a circulating water pump is connected to simulate the water circulation during the operation of the proton exchange membrane electrolyzer. The circulating water pump is equipped with a flow control component to adjust the water flow rate and simulate the electrolyte flow in the proton exchange membrane electrolyzer under different operating conditions.

3. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 1, characterized in that, In step A1, the EIS impedance measuring instrument includes a power excitation module and an impedance calculation module.

4. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 1, characterized in that, In step A1, the EIS impedance parameters include the EIS impedance magnitude, EIS phase angle, real part of impedance, imaginary part of impedance, and capacitance or resistance in the equivalent circuit method.

5. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 1, characterized in that, The specific steps for establishing the three-dimensional thermal model in step A3 are as follows: B1: Establish a three-dimensional model of each component of the proton exchange membrane electrolyzer in the numerical simulation analysis software. First, import the geometric model of the proton exchange membrane electrolyzer into the simulation software or establish the geometric model of the proton exchange membrane electrolyzer in the simulation software. Set the physicochemical parameters of each module in the geometric model. After setting, divide the geometric model into meshes and establish a three-dimensional simulation model. B2: Select a certain working condition for simulation, calculate the temperature at a certain position on the inner surface of the proton exchange membrane electrolyzer, and compare it with the experimental measurement value to determine the accuracy of the three-dimensional thermal model. If the accuracy meets the requirements, the three-dimensional thermal model is established; otherwise, return to step B1 to modify the model parameters of the three-dimensional model.

6. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 5, characterized in that, In step B1, the geometric model of the proton exchange membrane electrolyzer includes: an anode plate module, an oxygen chamber module, an anode diffusion layer module, a catalyst coating membrane module, a cathode diffusion layer module, a hydrogen chamber module, and a cathode plate module. The physicochemical parameters of each module in the geometric model specifically include: selecting heat-generating elements, setting physical fields, setting the heating power of heat-generating elements, specific heat capacity, thermal conductivity, and convective heat transfer coefficient of heat transfer elements, setting the conductivity of electrodes, setting the diffusion coefficient and flow rate of electrolyte, and setting boundary conditions. The heat-generating element is a catalyst-coated membrane, including a proton exchange membrane, an anode catalyst layer, and a cathode catalyst layer.

7. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 5, characterized in that, The calculation formulas for heat generation and heat transfer of each module within the geometric model are as follows: q c =h(T h -T l ) Where, q r The heat flux density representing heat conduction, q c The heat flux density represents heat convection, k represents thermal conductivity, h represents convective heat transfer coefficient, and T represents heat flux density. h T represents a higher temperature. l Representing a lower temperature, q represents the heat flux density of thermal radiation, σ represents the blackbody radiation constant, δ represents the emissivity, and T represents the lower temperature. a T represents the absolute temperature of the first radiating surface. b This represents the absolute temperature of the second radiating surface.

8. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 6, characterized in that, The kinetics of the electrode reaction within the geometric model are governed by the Butler-Volmer equation, calculated as follows: Among them, i a α represents the current density of the anode electrode. V,a i represents the specific surface area of ​​the anode gas diffusion electrode. o,a The exchange current density representing the anodic electrochemical reaction, α a The charge transfer coefficient of the anode is represented by F, and F represents the Faraday constant, η. act,a R represents the over-point potential of the anodic reaction, R represents the gas constant, and T represents the thermodynamic temperature. i c α represents the current density of the cathode electrode. V,c i represents the specific surface area of ​​the cathode gas diffusion electrode. o,c The exchange current density representing the cathodic electrochemical reaction, α c η represents the charge transfer coefficient of the cathode. act,c This represents the over-point of the cathode reaction.

9. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 6, characterized in that, The flow of liquid and gas in the geometric model is calculated using the continuity equation, the Navier-Stokes equation, and the total energy equation, as shown in the following formulas: Where ρ represents fluid density and t represents time. Represents the partial differential operator, u represents the fluid velocity, p represents the fluid pressure, τ represents the fluid stress tensor, g represents the gravitational acceleration, and C represents the partial differential operator. V represents specific heat capacity, T represents the temperature of the fluid, k represents the thermal conductivity, and Q represents the heat source per unit volume per unit time.

10. The method for measuring the internal temperature of a proton exchange membrane electrolyzer based on EIS impedance according to claim 9, characterized in that, In step A3, the internal temperature is the temperature at a certain location inside the proton exchange membrane electrolyzer, including the highest temperature, the lowest temperature, and the average temperature.

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