Method, device and equipment for analyzing output voltage of proton exchange membrane fuel cell

Abstract

The invention relates to the technical field of fuel cells, in particular to an output voltage analysis method, device and equipment of a proton exchange membrane fuel cell, and the method comprises the following steps: establishing an equivalent circuit model, a gas flow model and a thermodynamic model of a target proton exchange membrane fuel cell; constructing a simulation model of the proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and simulating stack starting based on the simulation model to obtain an output voltage change result and a temperature change result of the target proton exchange membrane fuel cell; and obtaining an output voltage analysis result of the target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result. Therefore, the problems that modeling based on an electrochemical model is limited in applicable scene and low in modeling precision are solved, the applicable scene is wide, and the modeling precision is accurate.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cells, and in particular to a method, device and equipment for analyzing the output voltage of a proton exchange membrane fuel cell. Background Art

[0002] Proton Exchange Membrane Fuel Cell (PEMFC) energy storage system has the advantages of high power density, high energy conversion efficiency, rapid start-up at low temperature and environmental friendliness. Applied in power systems, PEMFC can quickly participate in auxiliary services such as grid peak regulation and frequency regulation. The electrochemical laws and voltage output characteristics of PEMFC startup conditions directly affect its grid-related performance, mainly including the steady-state and dynamic characteristics of the output voltage, and therefore have been widely studied.

[0003] The modeling and analysis of the hydrogen-electric coupling system based on PEMFC already has good dynamic performance characteristics, but most of the previous considerations based on this model focused more on the dynamic behavior of the connection with the grid, without considering the actual dynamic characteristics of the PEMFC itself, resulting in inaccurate modeling.

[0004] In the study of PEMFC dynamic output characteristics in related technologies, the electrochemical model is widely used. The modeling of this model is relatively simple and it is easy to collect and fit the experimental parameters in actual engineering. By introducing empirical parameters for modeling, it is easy to show its electrical characteristics. However, this method has great limitations and cannot conduct more detailed analysis and research on more complex working conditions and its own characteristics. Summary of the invention

[0005] The present application provides a method, device and equipment for analyzing the output voltage of a proton exchange membrane fuel cell to solve the problems of limited applicable scenarios and low modeling accuracy of modeling based on electrochemical models. The method has a wide range of applicable scenarios and accurate modeling accuracy.

[0006] The first embodiment of the present application provides a method for analyzing the output voltage of a proton exchange membrane fuel cell, comprising the following steps:

[0007] Establish the equivalent circuit model, gas flow model and thermodynamic model of the target proton exchange membrane fuel cell;

[0008] Constructing a simulation model of the target proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and simulating the start-up of the fuel cell stack based on the simulation model to obtain output voltage change results and temperature change results of the target proton exchange membrane fuel cell;

[0009] The output voltage analysis result of the target proton exchange membrane fuel cell is obtained according to the output voltage change result and the temperature change result.

[0010] Optionally, in some embodiments, the equivalent circuit model of the target proton exchange membrane fuel cell is:

[0011] V fc =E Nernst -U act -U ohm -U con ;

[0012] Among them, V fc is the output voltage of a single battery, E Nernst is the Nernst voltage, U act is the activation overvoltage, U ohm is the ohmic overvoltage, U con is the concentration difference overvoltage.

[0013] Optionally, in some embodiments, obtaining the output voltage analysis result of the target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result includes:

[0014] Based on the equivalent circuit model, determining the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration difference overpotential according to the output voltage change result and the temperature change result;

[0015] The output voltage analysis result of the target proton exchange membrane fuel cell is generated according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration overpotential.

[0016] Optionally, in some embodiments, the gas flow model includes: an anode flow channel hydrogen pressure balance equation and a cathode flow channel oxygen pressure balance equation, wherein the anode flow channel hydrogen pressure balance equation is:

[0017]

[0018] in, is the hydrogen partial pressure, R is the gas constant, T is the battery temperature, V a is the total volume of the anode flow channel of the stack, is the molar mass of hydrogen entering the anode channel, is the molar flow rate of hydrogen participating in the electrochemical reaction; is the molar flow rate of hydrogen flowing out of the anode channel, is the hydrogen excess coefficient ratio, N is the number of battery cells, I is the current, Ka is the hydrogen flow coefficient, To relieve the pressure of hydrogen,

[0019] The oxygen pressure balance equation of the cathode flow channel is:

[0020]

[0021] in, is the oxygen partial pressure, V c is the total volume of the cathode flow channel of the stack, is the molar flow rate of oxygen entering the cathode channel, is the molar flow rate of oxygen participating in the electrochemical reaction, is the molar flow rate of oxygen flowing out of the cathode channel, is the oxygen excess coefficient ratio, K c is the oxygen flow coefficient, Relieve pressure for oxygen.

[0022] Optionally, in some embodiments, the thermodynamic model is:

[0023]

[0024] Among them, C t_fc is the stack heat capacity, T f ' c is the stack temperature, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the stack surface.

[0025] A second aspect of the present application provides an output voltage analysis device for a proton exchange membrane fuel cell, comprising:

[0026] Establishing a module for establishing an equivalent circuit model, a gas flow model and a thermodynamic model of a target proton exchange membrane fuel cell;

[0027] A simulation module, used for constructing a simulation model of the target proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and simulating the start-up of the fuel cell stack based on the simulation model to obtain output voltage change results and temperature change results of the target proton exchange membrane fuel cell;

[0028] An analysis module is used to obtain an output voltage analysis result of the target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result.

[0029] Optionally, in some embodiments, the equivalent circuit model of the target proton exchange membrane fuel cell is:

[0030] V fc =E Nernst -U act -U ohm -U con ;

[0031] Among them, V fc is the output voltage of a single battery, E Nernst is the Nernst voltage, U act is the activation overvoltage, U ohm is the ohmic overvoltage, U con is the concentration difference overvoltage.

[0032] Optionally, in some embodiments, the analysis module comprises:

[0033] a determination unit, configured to determine, based on the equivalent circuit model, the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration difference overpotential according to the output voltage change result and the temperature change result;

[0034] A generating unit is used to generate an output voltage analysis result of the target proton exchange membrane fuel cell according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential and the dynamic response characteristics of the concentration overpotential.

[0035] Optionally, in some embodiments, the gas flow model includes: an anode flow channel hydrogen pressure balance equation and a cathode flow channel oxygen pressure balance equation, wherein the anode flow channel hydrogen pressure balance equation is:

[0036]

[0037] in, is the hydrogen partial pressure, R is the gas constant, T is the battery temperature, V a is the total volume of the anode flow channel of the stack, is the molar mass of hydrogen entering the anode channel, is the molar flow rate of hydrogen participating in the electrochemical reaction; is the molar flow rate of hydrogen flowing out of the anode channel, is the hydrogen excess coefficient ratio, N is the number of battery cells, I is the current, K a is the hydrogen flow coefficient, To relieve the pressure of hydrogen,

[0038] The oxygen pressure balance equation of the cathode flow channel is:

[0039]

[0040] in, is the oxygen partial pressure, V c is the total volume of the cathode flow channel of the stack, is the molar flow rate of oxygen entering the cathode channel, is the molar flow rate of oxygen participating in the electrochemical reaction, is the molar flow rate of oxygen flowing out of the cathode channel, is the oxygen excess coefficient ratio, K c is the oxygen flow coefficient, Relieve pressure for oxygen.

[0041] Optionally, in some embodiments, the thermodynamic model is:

[0042]

[0043] Among them, C t_fc is the stack heat capacity, T f ' c is the stack temperature, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the stack surface.

[0044] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the output voltage analysis method of a proton exchange membrane fuel cell as described in the above embodiment.

[0045] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the output voltage analysis method of a proton exchange membrane fuel cell as described in the above embodiment.

[0046] Therefore, this application can be used to study the voltage output characteristics of proton exchange membrane fuel cells in hydrogen-electric coupling systems, optimize the output performance of hydrogen production systems, and enhance the understanding of the laws of multi-energy flow coupling within the system. Based on the basic electrochemical model of proton exchange membrane fuel cells, dynamic gas pressure and thermodynamic models are introduced to analyze the laws of voltage output; and the startup process is simulated by load current changes to study the "undershoot" phenomenon of the thermodynamic electromotive force and analyze its causes; based on the above analysis, the output response characteristics of the thermodynamic electromotive force, activation overpotential, ohmic overpotential and concentration difference overpotential that determine the output voltage of the battery are concluded.

[0047] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0049] Figure 1 A flow chart of a method for analyzing the output voltage of a proton exchange membrane fuel cell provided in accordance with an embodiment of the present application;

[0050] Figure 2 The schematic diagram of the working principle of a proton exchange membrane fuel cell and the thermal balance diagram of a fuel cell stack according to an embodiment of the present application is shown in FIG. Figure 2 (a) is a schematic diagram of the working principle of proton exchange membrane fuel cells. Figure 2 (b) is a schematic diagram of the thermal balance of the proton exchange membrane fuel cell stack;

[0051] Figure 3 The diagram is a schematic diagram of a polarization curve and a schematic diagram of each voltage loss curve of a proton exchange membrane fuel cell provided according to an embodiment of the present application, wherein: Figure 3 (a) is a schematic diagram of the polarization curve of a proton exchange membrane fuel cell. Figure 3 (b) is a schematic diagram of the voltage loss curves of the proton exchange membrane fuel cell;

[0052] Figure 4 This is a schematic diagram of the dynamic response of temperature and output voltage during the startup of a proton exchange membrane fuel cell according to an embodiment of the present application, wherein: Figure 4 (a) is a schematic diagram of the dynamic response of temperature and output voltage during the startup of the proton exchange membrane fuel cell. Figure 4 (b) is a schematic diagram of the dynamic response of the output voltage during the startup of the proton exchange membrane fuel cell;

[0053] Figure 5 The figure is a schematic diagram of the dynamic response of the thermodynamic electromotive force, activation overpotential, ohmic overpotential and concentration difference overpotential provided according to one embodiment of the present application, wherein: Figure 5 (a) is a schematic diagram of the dynamic response of thermodynamic electromotive force and activation overpotential. Figure 5 (b) is a schematic diagram of the dynamic response of ohmic overpotential and concentration difference overpotential;

[0054] Figure 6 A schematic diagram of the structure of an output voltage analysis device for a proton exchange membrane fuel cell provided according to an embodiment of the present application;

[0055] Figure 7It is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0056] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0057] The output voltage analysis method, device and equipment of the proton exchange membrane fuel cell of the embodiment of the present application are described below with reference to the accompanying drawings. In view of the limitations of the applicable scenarios of the modeling based on the electrochemical model mentioned in the above background technology and the low modeling accuracy, the present application provides an output voltage analysis method for a proton exchange membrane fuel cell, in which an equivalent circuit model, a gas flow model and a thermodynamic model of the target proton exchange membrane fuel cell are established, and a simulation model of the proton exchange membrane fuel cell is constructed according to the equivalent circuit model, the gas flow model and the thermodynamic model, and the output voltage change result and the temperature change result of the target proton exchange membrane fuel cell are obtained by simulating the start-up of the stack based on the simulation model, and the output voltage analysis result of the target proton exchange membrane fuel cell is obtained according to the output voltage change result and the temperature change result. Thus, the problem of the limitations of the applicable scenarios of the modeling based on the electrochemical model and the low modeling accuracy is solved, and the applicable scenarios are wide and the modeling accuracy is accurate.

[0058] Specifically, Figure 1 A schematic flow chart of a method for analyzing the output voltage of a proton exchange membrane fuel cell provided in an embodiment of the present application.

[0059] like Figure 1 As shown, the output voltage analysis method of the proton exchange membrane fuel cell includes the following steps:

[0060] In step S101, an equivalent circuit model, a gas flow model and a thermodynamic model of a target proton exchange membrane fuel cell are established.

[0061] It should be noted that the target proton exchange membrane fuel cell of the embodiment of the present application can be as follows Figure 2 As shown, Figure 2 The PEMFC working principle diagram and stack thermal balance diagram are provided.

[0062] Specifically, the embodiment of the present application can establish an equivalent circuit model of a target proton exchange membrane fuel cell. According to the output characteristics of PEMFC, the basic expression of the output voltage of a single cell can be:

[0063] V fc =E Nernst -Uact -U ohm -U con ; (1)

[0064] Among them, E Nernst is the Nernst voltage, U actt is the activation overvoltage, U ohm is the ohmic overvoltage, U con It is the concentration difference overvoltage.

[0065] in,

[0066]

[0067] Where ΔG is Gibbs free energy, ΔS is entropy change, F is Faraday constant, and T stack is the battery operating temperature, T ref is the reference temperature, R is the gas constant, and are the partial pressures of hydrogen and oxygen respectively, ξ1-ξ4 are parameter coefficients, is the oxygen concentration at the interface between the cathode film and the reaction gas; I is the output current of the battery, R c is the impedance of the external circuit, R M is the equivalent membrane impedance of the proton membrane, J is the current density of the battery, J max is the maximum current density, and b is the coefficient of the equation.

[0068] Based on the above electrochemical model, the four subsystems of Nernst voltage, activation overvoltage, ohmic overvoltage and concentration difference overvoltage can be encapsulated to obtain a steady-state simulation model of PEMFC.

[0069] Since the PEMFC stack is composed of n batteries connected in series, if the differences between the individual batteries are not considered, the accuracy of the output voltage of the entire stack will be reduced. Therefore, the stack can be divided into multiple units, and the following assumptions are made for each unit:

[0070] (1) The gases in the fuel cell are ideal gases and are evenly distributed;

[0071] (2) The gas pressure in the battery gas flow channel is equal everywhere;

[0072] (3) The temperature and humidity of the single cell are equal everywhere, and the water is liquid;

[0073] (4) The performance parameters of each single cell are the same, and the battery stack performance parameters are the accumulation of the performance parameters of each single cell.

[0074] Therefore, when the fuel cell stack is composed of n identical single cells connected in series, the stack voltage V stack It can be expressed as

[0075] Vstack =n·V fc ; (4)

[0076] Here, the embodiment of the present application can also establish a gas flow model of a target proton exchange membrane fuel cell.

[0077] Based on the above assumptions, the law of conservation of matter and the ideal gas state equation, it can be concluded that the reaction gas pressure is proportional to the gas content in the fuel cell stack. The gas content can be obtained by deducting the sum of the gas flow rate participating in the electrochemical reaction and the gas flow rate flowing out of the fuel cell stack from the gas flow rate entering the fuel cell stack, as shown in the following formula.

[0078] The hydrogen pressure balance equation in the anode channel is:

[0079]

[0080] in, is the hydrogen partial pressure, R is the gas constant, T is the battery temperature, V a is the total volume of the anode flow channel of the stack, is the molar mass of hydrogen entering the anode channel, is the molar flow rate of hydrogen participating in the electrochemical reaction; is the molar flow rate of hydrogen flowing out of the anode channel, is the hydrogen excess coefficient ratio, N is the number of battery cells, I is the current, K a is the hydrogen flow coefficient, To relieve the pressure of hydrogen,

[0081] The oxygen pressure balance equation in the cathode channel is:

[0082]

[0083] in, is the oxygen partial pressure, V c is the total volume of the cathode flow channel of the stack, is the molar flow rate of oxygen entering the cathode channel, is the molar flow rate of oxygen participating in the electrochemical reaction, is the molar flow rate of oxygen flowing out of the cathode channel, is the oxygen excess coefficient ratio, K c is the oxygen flow coefficient, Relieve pressure for oxygen.

[0084] Here, the embodiment of the present application can establish a thermodynamic model of a target proton exchange membrane fuel cell.

[0085] The thermodynamic model is not based on a single cell but on the entire battery stack. Figure 2 (b) The thermal equilibrium diagram and the law of conservation of energy establish the following dynamic equation:

[0086] According to the law of conservation of energy:

[0087]

[0088] In the formula, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the stack surface.

[0089] The heat balance equation of the battery stack can be expressed as:

[0090]

[0091] Among them, C t_fc is the heat capacity of the battery stack, T′ fc is the stack temperature, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the stack surface.

[0092] in,

[0093]

[0094] Where ΔH is the enthalpy of hydrogen combustion, is the rate of hydrogen consumption, UA HX_fc is a measure of the capacity of the heat exchanger, T cw,in and T cw,out are the temperatures of the inflow and outflow water, T amb is the ambient temperature, T′ fc is the stack temperature, R t_fc is the thermal resistance of the battery stack.

[0095] Among them, the coefficient UA HX_fc It can be calculated by the empirical formula:

[0096] UA HX_fc =h cond_fc +h conv_fc I fc ; (10)

[0097] In the formula, h cond_fc and h conv_fc are the conduction and convection parameters of the heat exchanger, respectively, and I fc is the stack current.

[0098] During the actual implementation process, the embodiment of the present application adds gas dynamics and thermodynamics models on the basis of the basic application model of proton exchange membrane fuel cells, takes into account the characteristics of the internal energy conversion mechanism, and adopts a differential dynamic model to describe in detail its internal heterogeneous energy conversion law, making the system more accurate and extensive in modeling accuracy and application scenarios, and describes in detail the change law and characteristics of its internal voltage components, which can effectively improve the understanding of the output change law of proton exchange membrane fuel cells and improve its modeling accuracy.

[0099] In step S102, a simulation model of a target proton exchange membrane fuel cell is constructed according to an equivalent circuit model, a gas flow model and a thermodynamic model, and the stack startup is simulated based on the simulation model to obtain output voltage change results and temperature change results of the target proton exchange membrane fuel cell.

[0100] The embodiment of the present application constructs a simulation model of a proton exchange membrane fuel cell based on an equivalent circuit model, a gas flow model, and a thermodynamic model. To verify and analyze the correctness of the simulation model established in the embodiment of the present application, the model is built and the subsystem is packaged in Matlab / Simulink. The system simulation parameters are shown in Table 1:

[0101] Table 1

[0102] parameter Value parameter Value ΔG 237.18 kJ / mol <![CDATA[R mem ]]> <![CDATA[0.003Ω / cm 2 ]]> F 96485C / mol <![CDATA[R ele ]]> <![CDATA[0.00024Ω / cm 2 ]]> R 8.314 J / (mol K) <![CDATA[A cell ]]> <![CDATA[400cm 2 ]]> <![CDATA[j0]]> <![CDATA[12×10 -8 A / cm 2 ]]> <![CDATA[V a ]]> <![CDATA[0.005m 3 ]]> <![CDATA[λ H2 ]]> 1.5 <![CDATA[K a ]]> 0.065mol / (s·atm) <![CDATA[P H2,p ]]> 3atm <![CDATA[V c ]]> <![CDATA[0.01m 3 ]]> <![CDATA[λ O2 ]]> 1.5 <![CDATA[K c ]]> 0.065mol / (s·atm) <![CDATA[P O2,p ]]> 3atm ΔH 285.5 kJ / mol

[0103] It is understandable that the steady-state performance of PEMFC is usually measured using polarization curves. Typical polarization curves are as follows: Figure 3 As shown in (a), the horizontal axis of the polarization curve is the current density, and the vertical axis is the output voltage of the battery. According to the change trend of the polarization curve, the polarization curve can be divided into three regions: activation polarization region, ohmic polarization region and concentration polarization region. Figure 3 (a) shows that as the current density increases, the output voltage shows a gradual downward trend. It drops faster at low current density, tends to be gentle at intermediate current density, and finally shows a rapid downward trend when approaching the limiting current density. The results are consistent with the changes in the theoretical polarization curve of the fuel cell, verifying the effectiveness of the simulation model.

[0104] Figure 3 In (b), as the current density increases, the activation polarization voltage first increases rapidly and then gradually stabilizes; the slope of the ohmic polarization voltage increases relatively constantly; and the concentration polarization voltage changes greatly when approaching the limiting current density.

[0105] After obtaining the simulation model of the target proton exchange membrane fuel cell, the startup process of the fuel cell stack can be simulated to perform dynamic performance simulation on the target proton exchange membrane fuel cell.

[0106] In the process of simulating the startup of the battery stack, the load current is mainly increased from 0 A to 20 A. Considering that the model is built in the Simulink environment, in order to avoid errors in operation caused by inputting 0 as the initial value into the system, the initial current is set from 0 A to 0.1 A. Figure 4 (a) is a simulation diagram of the dynamic response of the stack temperature and stack output voltage when the load current increases from 0.1A to 20A. It can be seen from the figure that at the moment of stack startup, the stack output voltage immediately drops from 36.5V 20 minutes ago, and then stabilizes at 27.35V; the stack temperature remains at 25℃ before 20 minutes, and after experiencing a sharp change in load current, the temperature rises slowly, and finally stabilizes at 40.8℃ after about 25 minutes.

[0107] In step S103, the output voltage analysis result of the target proton exchange membrane fuel cell is obtained according to the output voltage change result and the temperature change result.

[0108] Specifically, the simulation model constructed in the embodiment of the present application takes into account the impact of the temperature change of the battery stack on the dynamic performance of the battery stack. Figure 4 (a) The change of the output voltage of the fuel cell stack at the moment of startup, i.e., 20 minutes, is partially enlarged. Figure 4 As shown in (b), the stack output voltage dropped from 36.5V to 26.6V, then slowly rose for about 25 minutes and stabilized at 28.35V. This shows that the output voltage of the stack undershoots at the moment of startup, and the undershoot is 1.75V. At the same time, the stack output voltage undershoots, and the stack temperature response time is also as long as about 25 minutes, which is almost equal to the output voltage response time. Therefore, it can be inferred that during the startup of the PEMFC, the change in the stack temperature has a greater impact on the stack output performance.

[0109] Optionally, in some embodiments, the output voltage analysis results of the target proton exchange membrane fuel cell are obtained according to the output voltage change results and the temperature change results, including: based on an equivalent circuit model, determining the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration overpotential according to the output voltage change results and the temperature change results; generating the output voltage analysis results of the target proton exchange membrane fuel cell according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration overpotential.

[0110] The following will analyze and explain the dynamic response characteristics of the stack output voltage in the figure above from the perspective of stack temperature. According to formula (1), the output voltage of the PEMFC stack monomer is divided into four parts (thermodynamic electromotive force, activation overpotential, ohmic overpotential and concentration difference overpotential), and the dynamic response of the potential of each part during the startup process is analyzed. The dynamic characteristics of the voltage of each part are as follows: Figure 5 shown.

[0111] Depend on Figure 5 (a) It can be seen that the thermodynamic electromotive force is about 1.251V before startup. Its value remains unchanged at the moment of startup and then slowly decreases to 1.237V after about 25 minutes. This is mainly because the entropy of the system changes to a negative value when hydrogen and oxygen undergo electrochemical reaction. The increase in the temperature of the PEMFC stack after startup will cause the thermodynamic electromotive force of the monomer to decrease. Figure 5 (a) It can be seen that the activation overpotential before starting is 0.17V (due to the initial input current not being 0A). At the moment of starting, its value immediately rises from 0.17V to 0.53V, and then slowly drops to 0.51V after about 25 minutes. This is mainly because the temperature of the stack is low when it is just started, the catalyst activity is poor, the activation energy barrier is high, and a large voltage loss is required for the hydrogen-oxygen electrochemical reaction to occur. As the temperature of the stack slowly rises after starting, the catalyst activity also improves, the activation energy barrier decreases, and the activation overpotential slowly decreases. Figure 5 (b) It can be seen that the ohmic overpotential before startup is about 1.25×10 -4 V, the value immediately changes from 1.25×10 -4 V rises to 0.062V, and then slowly decreases to 0.048V after about 25 minutes. From formula (2), it can be seen that this is mainly due to the change in the equivalent resistance of the proton exchange membrane at the moment of startup, which leads to this change in ohmic overpotential. Figure 5 (b) It can be seen that the concentration difference overpotential before startup is 4.5×10 -6 V, its value immediately changes from 4.5×10 -6 V increases to 0.00118V and does not change with the stack temperature.

[0112] Through the analysis of the dynamic response of the above four parts of potential, it can be concluded that at the moment of stack startup, the PEMFC monomer thermodynamic electromotive force will not change immediately, but will slowly decrease with the increase of temperature, while the activation overpotential, ohmic overpotential and concentration difference overpotential will all increase immediately. Among them, the activation overpotential and ohmic overpotential both have overshoot phenomenon, which is also the main reason for the undershoot phenomenon of output voltage during stack startup.

[0113] It can be seen from the above figure that during the startup of the PEMFC stack, the response time of the voltage is basically consistent with the response time of the stack temperature, which is about 25 minutes.

[0114] According to the output voltage analysis method of the proton exchange membrane fuel cell proposed in the embodiment of the present application, by establishing an equivalent circuit model, a gas flow model and a thermodynamic model of the target proton exchange membrane fuel cell, and constructing a simulation model of the proton exchange membrane fuel cell based on the equivalent circuit model, the gas flow model and the thermodynamic model, the output voltage change result and the temperature change result of the target proton exchange membrane fuel cell are obtained by simulating the start-up of the stack based on the simulation model, and the output voltage analysis result of the target proton exchange membrane fuel cell is obtained based on the output voltage change result and the temperature change result. Thus, the problem of limited applicable scenarios and low modeling accuracy of modeling based on electrochemical models is solved, and the applicable scenarios are wide and the modeling accuracy is accurate.

[0115] Next, the output voltage analysis device of the proton exchange membrane fuel cell proposed in accordance with the embodiment of the present application will be described with reference to the accompanying drawings.

[0116] Figure 6 Schematic diagram of a block diagram of an output voltage analysis device for a proton exchange membrane fuel cell according to an embodiment of the present application.

[0117] like Figure 6 As shown, the output voltage analysis device 10 of the proton exchange membrane fuel cell includes: a building module 100 , a simulation module 200 and an analysis module 300 .

[0118] The establishment module 100 is used to establish an equivalent circuit model, a gas flow model and a thermodynamic model of a target proton exchange membrane fuel cell.

[0119] The simulation module 200 is used to construct a simulation model of the target proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and to simulate the stack startup based on the simulation model to obtain the output voltage change result and temperature change result of the target proton exchange membrane fuel cell.

[0120] The analysis module 300 is used to obtain an output voltage analysis result of a target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result.

[0121] Optionally, in some embodiments, the equivalent circuit model of the target proton exchange membrane fuel cell is:

[0122] V fc =E Nernst -U act -U ohm -U con ;

[0123] Among them, V fc is the output voltage of a single battery, E Nernst is the Nernst voltage, U actis the activation overvoltage, U ohm is the ohmic overvoltage, U con is the concentration difference overvoltage.

[0124] Optionally, in some embodiments, the analysis module includes: a determination unit and a generation unit.

[0125] Among them, the determination unit is used to determine the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential and the dynamic response characteristics of the concentration difference overpotential based on the equivalent circuit model and the output voltage change results and the temperature change results.

[0126] A generating unit is used to generate an output voltage analysis result of a target proton exchange membrane fuel cell according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential and the dynamic response characteristics of the concentration difference overpotential.

[0127] Optionally, in some embodiments, the gas flow model includes: an anode flow channel hydrogen pressure balance equation and a cathode flow channel oxygen pressure balance equation, wherein the anode flow channel hydrogen pressure balance equation is:

[0128]

[0129] in, is the hydrogen partial pressure, R is the gas constant, T is the battery temperature, V a is the total volume of the anode flow channel of the stack, is the molar mass of hydrogen entering the anode channel, is the molar flow rate of hydrogen participating in the electrochemical reaction; is the molar flow rate of hydrogen flowing out of the anode channel, is the hydrogen excess coefficient ratio, N is the number of battery cells, I is the current, K a is the hydrogen flow rate, To relieve the pressure of hydrogen,

[0130] The oxygen pressure balance equation in the cathode channel is:

[0131]

[0132] in, is the oxygen partial pressure, V c is the total volume of the cathode flow channel of the stack, is the molar flow rate of oxygen entering the cathode channel, is the molar flow rate of oxygen participating in the electrochemical reaction, is the molar flow rate of oxygen flowing out of the cathode channel, is the oxygen excess coefficient ratio, K c is the oxygen flow coefficient, Relieve pressure for oxygen.

[0133] Optionally, in some embodiments, the thermodynamic model is:

[0134]

[0135] Among them, C t_fc is the stack heat capacity, T f ' c is the stack temperature, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the stack surface.

[0136] It should be noted that the above explanation of the embodiment of the output voltage analysis method of the proton exchange membrane fuel cell is also applicable to the output voltage analysis device of the proton exchange membrane fuel cell of this embodiment, and will not be repeated here.

[0137] According to the output voltage analysis device of the proton exchange membrane fuel cell proposed in the embodiment of the present application, by establishing an equivalent circuit model, a gas flow model and a thermodynamic model of the target proton exchange membrane fuel cell, a simulation model of the proton exchange membrane fuel cell is constructed based on the equivalent circuit model, the gas flow model and the thermodynamic model, and the output voltage change result and temperature change result of the target proton exchange membrane fuel cell are obtained by simulating the start-up of the stack based on the simulation model, and the output voltage analysis result of the target proton exchange membrane fuel cell is obtained based on the output voltage change result and the temperature change result. Thus, the problem of limited applicable scenarios and low modeling accuracy of modeling based on electrochemical models is solved, and the applicable scenarios are wide and the modeling accuracy is accurate.

[0138] Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0139] A memory 701 , a processor 702 , and a computer program stored in the memory 701 and executable on the processor 702 .

[0140] When the processor 702 executes the program, the output voltage analysis method of the proton exchange membrane fuel cell provided in the above embodiment is implemented.

[0141] Furthermore, the electronic device further comprises:

[0142] The communication interface 703 is used for communication between the memory 701 and the processor 702 .

[0143] The memory 701 is used to store computer programs that can be executed on the processor 702 .

[0144] The memory 701 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0145] If the memory 701, the processor 702 and the communication interface 703 are implemented independently, the communication interface 703, the memory 701 and the processor 702 can be connected to each other through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0146] Optionally, in a specific implementation, if the memory 701, the processor 702 and the communication interface 703 are integrated on a chip, the memory 701, the processor 702 and the communication interface 703 can communicate with each other through an internal interface.

[0147] The processor 702 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0148] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for analyzing the output voltage of a proton exchange membrane fuel cell.

[0149] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0150] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0151] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0152] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0153] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0154] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for analyzing the output voltage of a proton exchange membrane fuel cell, characterized in that: The following steps are involved: Establish the equivalent circuit model, gas flow model and thermodynamic model of the target proton exchange membrane fuel cell; Constructing a simulation model of the target proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and simulating the start-up of the fuel cell stack based on the simulation model to obtain output voltage change results and temperature change results of the target proton exchange membrane fuel cell; The output voltage analysis result of the target proton exchange membrane fuel cell is obtained according to the output voltage change result and the temperature change result.

2. The method according to claim 1, characterized in that The equivalent circuit model of the target proton exchange membrane fuel cell is: V fc =E Nernst -IN act -IN ohm -IN con ; Among them, V fc is the output voltage of a single battery, E Nernst is the Nernst voltage, U act is the activation overvoltage, U ohm is the ohmic overvoltage, U con is the concentration difference overvoltage.

3. The method according to claim 2, characterized in that The step of obtaining the output voltage analysis result of the target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result includes: Based on the equivalent circuit model, determining the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration difference overpotential according to the output voltage change result and the temperature change result; The output voltage analysis result of the target proton exchange membrane fuel cell is generated according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration overpotential.

4. The method according to claim 1, characterized in that: The gas flow model includes: an anode flow channel hydrogen pressure balance equation and a cathode flow channel oxygen pressure balance equation, wherein the anode flow channel hydrogen pressure balance equation is: in, is the hydrogen partial pressure, R is the gas constant, T is the battery temperature, V a is the total volume of the anode flow channel of the stack, is the molar mass of hydrogen entering the anode channel, is the molar flow rate of hydrogen participating in the electrochemical reaction; is the molar flow rate of hydrogen flowing out of the anode channel, is the hydrogen excess coefficient ratio, N is the number of battery cells, I is the current, K a is the hydrogen flow coefficient, To relieve the pressure of hydrogen, The oxygen pressure balance equation of the cathode flow channel is: in, is the oxygen partial pressure, V c is the total volume of the cathode flow channel of the stack, is the molar flow rate of oxygen entering the cathode channel, is the molar flow rate of oxygen participating in the electrochemical reaction, is the molar flow rate of oxygen flowing out of the cathode channel, is the oxygen excess coefficient ratio, K c is the oxygen flow coefficient, Relieve pressure for oxygen.

5. The method according to claim 1, characterized in that The thermodynamic model is: Among them, C t_fc is the stack heat capacity, T f ' c is the stack temperature, is the stack heat absorption rate, P tot_fc is the total mass entering the stack, P fc is the power consumed by the load, is the speed at which cooling water removes heat. is the heat loss rate on the surface of the battery stack.

6. An output voltage analysis device for a proton exchange membrane fuel cell, characterized in that: include: Establishing a module for establishing an equivalent circuit model, a gas flow model and a thermodynamic model of a target proton exchange membrane fuel cell; A simulation module, used for constructing a simulation model of the target proton exchange membrane fuel cell according to the equivalent circuit model, the gas flow model and the thermodynamic model, and simulating the start-up of the fuel cell stack based on the simulation model to obtain output voltage change results and temperature change results of the target proton exchange membrane fuel cell; An analysis module is used to obtain an output voltage analysis result of the target proton exchange membrane fuel cell according to the output voltage change result and the temperature change result.

7. The device according to claim 6, characterized in that The equivalent circuit model of the target proton exchange membrane fuel cell is: V fc =E Nernst -IN act -IN ohm -IN con ; Among them, V fc is the output voltage of a single battery, E Nernst is the Nernst voltage, U act is the activation overvoltage, U ohm is the ohmic overvoltage, U con is the concentration difference overvoltage.

8. The device according to claim 7, characterized in that The analysis module comprises: a determination unit, configured to determine, based on the equivalent circuit model, the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential, and the dynamic response characteristics of the concentration difference overpotential according to the output voltage change result and the temperature change result; A generating unit is used to generate an output voltage analysis result of the target proton exchange membrane fuel cell according to the dynamic response characteristics of the thermodynamic electromotive force, the dynamic response characteristics of the activation overpotential, the dynamic response characteristics of the ohmic overpotential and the dynamic response characteristics of the concentration overpotential.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the output voltage analysis method for a proton exchange membrane fuel cell as described in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the output voltage analysis method of a proton exchange membrane fuel cell as described in any one of claims 1 to 5.

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