Fuel cell recovery method
By operating at high current density and low voltage and reducing the cathode metering ratio to achieve an under-oxygen state, the problem of lack of fuel cell recovery methods in the prior art without additional pipeline control systems or inert gas is solved, and the recovery of fuel cell performance and the improvement of catalyst activity is achieved.
Patent Information
- Application Number
- CN202411581711.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-03-04
AI Technical Summary
There is a lack of a variety of reversible attenuation methods for resuming reversible attenuation of fuel cell recovery using reactants available in fuel cell systems in the absence of additional pipeline control systems or inert gases.
By obtaining the reference voltage of the fuel cell, controlling it to operate at high current density and low voltage, the cathode metering ratio is reduced to achieve an under-oxygen state, and continuing to operate at low current density to restore the catalytic layer.
It is achieved without additional pipeline control systems or inert gases to restore the performance of the fuel cell, remove impurities, increase the activity of the catalyst, and quickly reduce the oxides in the catalytic layer.
Smart Images
Figure CN119560592A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of fuel cells, and in particular to a fuel cell recovery method. Background Art
[0002] Proton exchange membrane fuel cells are electrochemical devices that can convert chemical energy into electrical energy. They are widely used in the fields of transportation and engineering machinery because of their advantages such as high energy conversion rate, no pollution, and fast startup speed. However, their rapid performance degradation and short lifespan seriously hinder the large-scale commercialization of fuel cells. There are many mechanisms that lead to the degradation of proton exchange membrane fuel cells, such as the oxide film formed on the surface of the Pt catalyst, the poisoning of the catalyst by pollutants, the adsorption of impurities on the catalyst surface, and flooding / membrane drying caused by long-term operation of the stack. These reversible losses can be restored through some specific operations, thereby extending the service life of the stack and enhancing durability.
[0003] The related art usually uses a hydrogen pump method to recover the fuel cell. This method requires external current excitation and additional supply of inert gas to the cathode. The related art also uses a loading and unloading cycle operation method. This method is more suitable for the activation of new fuel cells and has a poor effect on the recovery of fuel cell performance. The related art also uses the cathode "oxygen starvation" principle to recover the fuel cell, but the additional pipelines and pulse controllers will increase the complexity of the fuel cell system and its control strategy. Although this method can increase the reduction rate of the oxide in the cathode catalyst layer, it will increase the concentration of hydrogen in the cathode cavity. When the cathode is passed through air again, it is more likely to cause catalytic combustion reactions in the catalyst layer, which also creates greater safety hazards.
[0004] Therefore, it is particularly important to develop a fuel cell recovery method that can recover multiple reversible decays using available reactants in the fuel cell system without additional piping control systems or inert gases. Summary of the invention
[0005] To solve the above technical problems, the present application provides a fuel cell recovery method that can solve the current problem of lack of a fuel cell recovery method that can recover multiple reversibly decayed fuel cells using available reactants in the fuel cell system without additional pipeline control systems or inert gases.
[0006] The technical solutions provided by this application are as follows:
[0007] The present application provides a fuel cell recovery method, the fuel cell recovery method comprising:
[0008] Obtaining a reference voltage of the fuel cell;
[0009] Controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time, wherein the first preset current density is greater than a first preset current density threshold, and the first preset voltage is less than a first preset voltage threshold;
[0010] reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density;
[0011] measuring a target voltage of the fuel cell after the fuel cell has been running for the second preset time;
[0012] The reference voltage and the target voltage are compared, and a recovery result of the fuel cell is generated based on the comparison result.
[0013] In some optional embodiments, operating the fuel cell at a first preset current density and a first preset voltage for a first preset time, wherein the first preset current density is greater than a first preset current density threshold, and the first preset voltage is less than a first preset voltage threshold, comprises:
[0014] The current density of the fuel cell is increased to the first preset current density so that the operating voltage of the fuel cell is lower than the first preset voltage, and the fuel cell is controlled to operate at the first preset current density and the first preset voltage for a first preset time; the first preset time ranges from 10min to 20min.
[0015] In some optional embodiments, the step of reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density, comprises:
[0016] reducing the current density of the fuel cell from the first preset current density to the second preset current density;
[0017] reducing the cathode stoichiometric ratio of the fuel cell to a second preset cathode stoichiometric ratio, and controlling the fuel cell to operate at the second preset cathode stoichiometric ratio and the second preset current density for a third preset time;
[0018] reducing the cathode stoichiometric ratio of the fuel cell from the second preset cathode stoichiometric ratio to the preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a fourth preset time at the second preset current density and the oxygen-deficient state;
[0019] The range of the third preset time is 0min-5min; the range of the fourth preset time is 0min-10min; the second preset time includes the third preset time and the fourth preset time.
[0020] In some optional embodiments, after operating the fuel cell at the first preset current density and the first preset voltage for a first preset time, the method further comprises:
[0021] Increasing the cathode stoichiometric ratio of the fuel cell to a first preset cathode stoichiometric ratio, and controlling the fuel cell to operate at the first preset current density for a fifth preset time; wherein the fifth preset time ranges from 0 min to 5 min;
[0022] In some optional implementations, obtaining the reference voltage of the fuel cell includes:
[0023] Obtaining a first reference voltage of the fuel cell at a first target current density; obtaining a second reference voltage of the fuel cell at a second target current density; obtaining a third reference voltage of the fuel cell at a third target current density;
[0024] The first reference voltage, the second reference voltage, and the third reference voltage are determined as the reference voltages.
[0025] In some optional implementations, measuring the target voltage of the fuel cell after running for a second preset time includes:
[0026] Repeat the steps of controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time, to controlling the fuel cell to operate at a second preset current density and an oxygen-deficient state for a second preset time;
[0027] measuring a first target voltage of the fuel cell at the first target current density; measuring a second target voltage of the fuel cell at the second target current density; measuring a third target voltage of the fuel cell at the third target current density;
[0028] The first target voltage, the second target voltage, and the third target voltage are determined as the target voltages.
[0029] In some optional implementations, comparing the reference voltage with the target voltage and generating a recovery result of the fuel cell based on the comparison result includes:
[0030] determining a difference between the reference voltage and the target voltage;
[0031] A recovery result of the fuel cell is generated according to a difference between the reference voltage and the target voltage.
[0032] In some optional implementations, determining the difference between the reference voltage and the target voltage includes:
[0033] A first difference between the first target voltage and the first reference voltage is determined; a second difference between the second target voltage and the second reference voltage is determined; and a third difference between the third target voltage and the third reference voltage is determined.
[0034] In some optional implementations, generating a recovery result of the fuel cell according to a difference between the reference voltage and the target voltage includes:
[0035] When the first difference, the second difference, and the third difference are all smaller than a preset difference threshold, determining that the recovery result of the fuel cell is a result that the fuel cell is fully recovered;
[0036] When any one of the first difference, the second difference, and the third difference is greater than or equal to the preset difference threshold, it is determined that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered.
[0037] In some optional embodiments, after determining that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered, the method further includes:
[0038] Controlling the fuel cell to operate at the second current density for a fifth preset time, wherein the fifth preset time ranges from 0 min to 10 min;
[0039] Restoring the cathode stoichiometric ratio of the fuel cell to the second preset cathode stoichiometric ratio, and controlling the fuel cell to operate for a sixth preset time at the second preset cathode stoichiometric ratio; wherein the sixth preset time ranges from 0 min to 5 min, and the second preset cathode stoichiometric ratio is greater than the preset cathode stoichiometric ratio;
[0040] Repeat the steps of reducing the cathode metering ratio of the fuel cell to a preset cathode metering ratio, comparing the reference voltage and the target voltage, and generating a recovery result of the fuel cell based on the comparison result, until it is determined that the recovery result of the fuel cell is a result of complete recovery of the fuel cell, or the number of times the recovery result of the fuel cell is generated is greater than a preset maximum number of times.
[0041] The fuel cell recovery method provided by the present application obtains a reference voltage of the fuel cell; operates the fuel cell at a first preset current density and a first preset voltage for a first preset time, wherein the first preset current density is greater than the first preset current density threshold, and the first preset voltage is less than the first preset voltage threshold, and the large gas flow rate and the large amount of condensed water generated at a large current density can remove impurities that block pores in the gas diffusion layer and adsorb on the surface of the catalyst, which is conducive to constructing a transmission channel for water and gas, and increasing the active reaction sites of the catalyst, and the low voltage at a large current density is also helpful to reduce the oxides in the catalyst layer. The cathode stoichiometric ratio of the fuel cell is reduced to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and the fuel cell is controlled to operate for a second preset time at a second preset current density and an oxygen-deficient state, wherein the second preset current density is less than the first preset current density; the target voltage of the fuel cell after the second preset time is measured; the reference voltage and the target voltage are compared, and a recovery result of the fuel cell is generated based on the comparison result, wherein the oxygen-deficient operation at a small current density can quickly reduce the oxides in the catalyst layer using the low voltage and the hydrogen generated at the cathode, and the fuel cell is effectively recovered, and multiple reversible decays are recovered using the available reactants in the fuel cell system without an additional pipeline control system or an inert gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0043] Figure 1 is a flow chart of a fuel cell recovery method according to an embodiment of the present invention. DETAILED DESCRIPTION
[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0045] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0046] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.
[0047] Since there is currently a lack of a fuel cell recovery method that can use available reactants in the fuel cell system to recover multiple reversible decays without an additional pipeline control system or inert gas, in order to effectively remove impurities that clog the pores in the gas diffusion layer and adsorb on the catalyst surface, construct a water and gas transmission channel, increase the active reaction sites of the catalyst, and quickly reduce the oxides in the catalytic layer, the present application provides a fuel cell recovery method that uses available reactants in the fuel cell system to recover multiple reversible decays without an additional pipeline control system or inert gas.
[0048] See also Figure 1 , Figure 1 This is a flow chart of a fuel cell recovery method proposed according to an embodiment of the present invention. The present application provides a fuel cell recovery method, the fuel cell recovery method comprising:
[0049] S101. Obtain a reference voltage of the fuel cell.
[0050] Optionally, the fuel cell is a fuel cell stack composed of a plurality of fuel cell units, ie, monolithic cells.
[0051] In an optional embodiment, obtaining the reference voltage of the fuel cell includes:
[0052] Obtaining a first reference voltage of the fuel cell at a first target current density; obtaining a second reference voltage of the fuel cell at a second target current density; obtaining a third reference voltage of the fuel cell at a third target current density;
[0053] The first reference voltage, the second reference voltage, and the third reference voltage are determined as the reference voltages.
[0054] Optionally, the reference voltage is the voltage of the fuel cell at three target current densities.
[0055] Optionally, the first target current density, the second target current density, and the third target current density can be set according to actual business needs, and are not limited here. For example, the first target current density can be 100 mA / cm 2 , the second target current density can be 1000mA / cm 2 , the third target current density can be 2000mA / cm 2 .
[0056] Optionally, before obtaining the reference voltage of the fuel cell, the fuel cell is connected to a load, hydrogen is introduced to the anode of the fuel cell, air is introduced to the cathode, and then the fuel cell is tested at 100 mA / cm 2 , 1000mA / cm 2 , 2000mA / cm 2 The reference voltage.
[0057] By measuring the reference voltage, a reference point can be established to represent the initial voltage level before the fuel cell begins to recover, so that by comparing the difference between the voltage after recovery and the reference voltage, it can be more accurately determined whether the performance of the fuel cell has recovered to the expected level; using the reference voltage as a reference can ensure that there is a uniform standard each time the fuel cell recovery is evaluated, which improves the repeatability of the results and the efficiency and quality of fuel cell maintenance and management.
[0058] S102. Operate the fuel cell at a first preset current density and a first preset voltage for a first preset time, wherein the first preset current density is greater than a first preset current density threshold, and the first preset voltage is less than a first preset voltage threshold.
[0059] In an optional embodiment, controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time includes:
[0060] The current density of the fuel cell is increased to the first preset current density so that the operating voltage of the fuel cell is lower than the first preset voltage, and the fuel cell is controlled to operate at the first preset current density and the first preset voltage for a first preset time; the first preset time ranges from 10min to 20min.
[0061] Optionally, the fuel cell is loaded to a first preset current density, wherein the first preset current density can be set according to the performance of the fuel cell itself, which is not limited here. For example, the fuel cell can be loaded to 2500 mA / cm 2 or 2600mA / cm 2 or 2700mA / cm 2 of high current density.
[0062] Optionally, the first preset current density threshold and the first preset voltage threshold can be set according to actual business needs and are not limited here. For example, the first preset current density threshold can be the current density at which the fuel cell can operate normally, and the first preset voltage threshold can be 0.4V.
[0063] Optionally, the first preset time can be set according to actual business needs and is not limited here. Exemplarily, the first preset time can be 15 minutes.
[0064] Optionally, the fuel cell is operated at 2500 mA / cm 2 or 2600mA / cm 2 or 2700mA / cm 2 The high current density can be maintained for 15 minutes while the voltage of the fuel cell is kept below 0.4V. The condition that the minimum single cell voltage is greater than 0.05V can be increased to protect the fuel cell.
[0065] By operating under high current density and low voltage conditions, part of the oxide can be reduced and the membrane electrode can be wetted at the same time; and a large amount of condensed water will be generated under high current density, which can remove impurities that block the pores in the gas diffusion layer and impurities adsorbed on the catalyst surface, which is beneficial to constructing water and gas transmission channels and increasing the active reaction sites of the catalyst.
[0066] S103. Reduce the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and control the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density.
[0067] Optionally, the cathode stoichiometric ratio of the fuel cell refers to the molar ratio of oxygen to hydrogen in the cathode reaction, or the ratio of the amount of oxygen involved in the reaction to the theoretical amount of oxygen required. The preset cathode stoichiometric ratio can be set according to actual business needs, and is not limited here. For example, the preset cathode stoichiometric ratio can be set to a cathode stoichiometric ratio less than 1, and can be set to 0.7.
[0068] Optionally, the second preset current density can be set according to actual business needs, which is not limited here. For example, the second preset current density can be 200 mA / cm 2 .
[0069] In an optional embodiment, the step of reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density, comprises:
[0070] reducing the current density of the fuel cell from the first preset current density to the second preset current density;
[0071] Setting the cathode stoichiometric ratio of the fuel cell to a second preset cathode stoichiometric ratio, and controlling the fuel cell to operate at the second preset cathode stoichiometric ratio and the second preset current density for a third preset time;
[0072] reducing the cathode stoichiometric ratio of the fuel cell from the second preset cathode stoichiometric ratio to the preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a fourth preset time at the second preset current density and the oxygen-deficient state;
[0073] The range of the third preset time is 0min-5min; the range of the fourth preset time is 0min-10min; the second preset time includes the third preset time and the fourth preset time.
[0074] Optionally, the second preset cathode stoichiometric ratio can be set according to actual business needs, which is not limited here. For example, the second preset cathode stoichiometric ratio can be 200 mA / cm 2 The cathode stoichiometric ratio allows normal operation at low current densities.
[0075] Optionally, the third preset time ranges from 0min to 5min, which can be set according to actual business needs, and is not limited here. For example, the third preset time can be 3min. The fourth preset time ranges from 0min to 10min, which can be set according to actual business needs, and is not limited here. For example, the fourth preset time can be 5min.
[0076] Optionally, the fuel cell is deloaded by reducing the current density of the fuel cell from 2500 mA / cm 2 or 2600mA / cm 2 or 2700mA / cm 2 The maximum current density is reduced to 200 mA / cm 2 The cathode stoichiometric ratio was gradually reduced until it reached 0.7. The cathode stoichiometric ratio was 200 mA / cm 2 The reaction was run for 5 min at a current density of 1.50 and a cathode stoichiometry of 0.7.
[0077] Optionally, at 200 mA / cm 2 During the operation of low current density, the single cell voltage of the fuel cell can be guaranteed to be greater than 0.05V. If the single cell voltage is lower than 0.05V, the cathode stoichiometric ratio can be appropriately increased to protect the battery.
[0078] By operating at low current density with oxygen deficiency, low voltage and hydrogen generated at the cathode can quickly reduce the oxides in the catalyst layer, effectively recovering the fuel cell.
[0079] In an optional embodiment, after operating the fuel cell at the first preset current density and the first preset voltage for a first preset time, the method further comprises:
[0080] The cathode stoichiometric ratio of the fuel cell is increased to a first preset cathode stoichiometric ratio, and the fuel cell is controlled to operate at the first preset current density for a fifth preset time; wherein the fifth preset time ranges from 0 min to 5 min.
[0081] Optionally, the first preset cathode stoichiometric ratio can be set according to the performance of the fuel cell, which is not limited here. For example, if the cathode stoichiometric ratio of the fuel cell under high current density is 1.8, it can be increased to 1.9 or 2; if the cathode stoichiometric ratio of the fuel cell under high current density is 2, it can be increased to 2.1 or 2.2.
[0082] Optionally, the range of the fifth preset time is 0min-5min, which can be set according to actual business needs and is not limited here. Exemplarily, the fifth preset time can be 2min.
[0083] Optionally, the cathode stoichiometric ratio of the fuel cell is increased to a first preset cathode stoichiometric ratio, and the fuel cell is controlled to operate at a high current density for 2 minutes, so that excess liquid water can be purged to avoid local flooding during the next load reduction process.
[0084] S104. Measure the target voltage of the fuel cell after running for a second preset time.
[0085] In an optional embodiment, measuring the target voltage of the fuel cell after running for a second preset time includes:
[0086] Repeat the steps of controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time, to controlling the fuel cell to operate at a second preset current density and an oxygen-deficient state for a second preset time;
[0087] measuring a first target voltage of the fuel cell at the first target current density; measuring a second target voltage of the fuel cell at the second target current density; measuring a third target voltage of the fuel cell at the third target current density;
[0088] The first target voltage, the second target voltage, and the third target voltage are determined as the target voltages.
[0089] Optionally, the fuel cell is measured after running for a second preset time at 100 mA / cm 2 , 1000mA / cm 2 , 2000mA / cm 2 The target voltages under the current density of are respectively used as the first target voltage, the second target voltage, and the third target voltage.
[0090] S105. Compare the reference voltage and the target voltage, and generate a recovery result of the fuel cell based on the comparison result.
[0091] In an optional embodiment, comparing the reference voltage with the target voltage and generating a recovery result of the fuel cell based on the comparison result includes:
[0092] determining a difference between the reference voltage and the target voltage;
[0093] A recovery result of the fuel cell is generated according to a difference between the reference voltage and the target voltage.
[0094] In an optional embodiment, determining the difference between the reference voltage and the target voltage includes:
[0095] A first difference between the first target voltage and the first reference voltage is determined; a second difference between the second target voltage and the second reference voltage is determined; and a third difference between the third target voltage and the third reference voltage is determined.
[0096] In an optional embodiment, generating the recovery result of the fuel cell according to the difference between the reference voltage and the target voltage includes:
[0097] When the first difference, the second difference, and the third difference are all smaller than a preset difference threshold, determining that the recovery result of the fuel cell is a result that the fuel cell is fully recovered;
[0098] When any one of the first difference, the second difference, and the third difference is greater than or equal to the preset difference threshold, it is determined that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered.
[0099] Optionally, the preset difference threshold may be set according to actual business requirements, which is not limited here. Exemplarily, the preset difference threshold may be 5 mV.
[0100] Optionally, at 100 mA / cm 2 , 1000mA / cm 2 , 2000mA / cm 2 The three target voltages measured at current density of 100 mA / cm 2 , 1000mA / cm 2 , 2000mA / cm 2 When the three differences of the reference voltage at the current density are all less than 5 mV, the recovery result of the fuel cell is determined to be a result that the fuel cell has fully recovered. When any one of the above three differences is greater than or equal to 5 mV, the recovery result of the fuel cell is determined to be a result that the fuel cell has not fully recovered.
[0101] Difference comparison provides a direct quantitative indicator, which helps to accurately determine whether the performance of the fuel cell has returned to normal levels. Using a fixed reference voltage as a comparison standard ensures the consistency of the test results, making the recovery evaluation comparable. In addition, multiple differences represent the performance of the fuel cell under different working conditions, which can provide a more detailed performance evaluation and improve the accuracy of the evaluation results.
[0102] In an optional embodiment, after determining that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered, the method further includes:
[0103] operating the fuel cell at the second current density for a fifth preset time, wherein the fifth preset time ranges from 0 min to 10 min;
[0104] The cathode stoichiometric ratio of the fuel cell is restored to the second preset cathode stoichiometric ratio, and the fuel cell is operated for a sixth preset time at the second preset cathode stoichiometric ratio; wherein the sixth preset time ranges from 0 min to 5 min, and the second preset cathode stoichiometric ratio is greater than the preset cathode stoichiometric ratio;
[0105] Repeat the steps of reducing the cathode metering ratio of the fuel cell to a preset cathode metering ratio, comparing the reference voltage and the target voltage, and generating a recovery result of the fuel cell based on the comparison result, until it is determined that the recovery result of the fuel cell is a result of complete recovery of the fuel cell, or the number of times the recovery result of the fuel cell is generated is greater than a preset maximum number of times.
[0106] Optionally, the range of the fifth preset time is 0min-10min, which can be set according to actual business needs and is not limited here. Exemplarily, the fifth preset time can be 5min.
[0107] Optionally, the range of the sixth preset time is 0min-5min, which can be set according to actual business needs and is not limited here. Exemplarily, the sixth preset time can be 2min.
[0108] Optionally, the preset maximum number of times can be set according to actual business needs and is not limited here. Exemplarily, the preset maximum number of times can be 4 times or 6 times.
[0109] Optionally, after determining that the recovery result of the fuel cell is that the fuel cell has not been fully recovered, the cathode stoichiometric ratio of the fuel cell is restored to a level where the fuel cell has a current of 200 mA / cm 2 the cathode stoichiometric ratio that can operate normally under a small current density, controlling the fuel cell to operate at the cathode stoichiometric ratio for 2 minutes, repeatedly reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio, until comparing the reference voltage and the target voltage, and generating a recovery result of the fuel cell based on the comparison result, until it is determined that the recovery result of the fuel cell is a result of complete recovery of the fuel cell, or the number of times the recovery result of the fuel cell is generated is greater than a preset maximum number of times.
[0110] After determining that the recovery result of the fuel cell is that the fuel cell has not been fully recovered, the fuel cell is repeatedly recovered until the recovery result is that the fuel cell has been fully recovered, or the number of recovery results of the fuel cell is judged to be greater than a preset maximum number, which can ensure that the performance of the fuel cell is restored to the best state as much as possible, improve its working efficiency and reliability, and ensure that the performance of the fuel cell reaches the predetermined standard and meets the use requirements.
[0111] The fuel cell recovery method provided in the present application obtains a reference voltage of the fuel cell; operates the fuel cell at a first preset current density and a first preset voltage for a first preset time, the first preset current density is greater than a first preset current density threshold, and the first preset voltage is less than a first preset voltage threshold, the cathode stoichiometric ratio of the fuel cell is reduced to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controls the fuel cell to operate at a second preset current density and an oxygen-deficient state for a second preset time, the second preset current density is less than the first preset current density; measures a target voltage of the fuel cell after the fuel cell has been running for the second preset time; compares the reference voltage and the target voltage, and generates a recovery result of the fuel cell based on the comparison result.
[0112] The following is an overall description of the fuel cell recovery method proposed in one embodiment of the present application:
[0113] Connect the fuel cell to the load, introduce hydrogen to the anode of the fuel cell, introduce air to the cathode, and obtain the fuel at 100mA / cm 2 , 1000mA / cm 2 , 2000mA / cm 2 The reference voltage at the current density of
[0114] Load the fuel cell to 2500mA / cm 2 or 2600mA / cm 2 or 2700mA / cm 2 The fuel cell is controlled to operate at a high current density for 15 minutes, while the voltage of the fuel cell is kept below 0.4V, and the condition that the minimum single cell voltage is greater than 0.05V can be increased to protect the fuel cell;
[0115] Increasing the cathode stoichiometric ratio of the fuel cell to a first preset cathode stoichiometric ratio, and controlling the fuel cell to operate at a high current density for 2 minutes, so as to purge excess liquid water and avoid local flooding during the next load reduction process;
[0116] The current density of the fuel cell was increased from 2500 mA / cm 2 or 2600mA / cm 2 or 2700mA / cm 2The maximum current density is reduced to 200 mA / cm 2 The current density was kept at a low level and the cathode stoichiometric ratio was maintained for 3 min. The cathode stoichiometric ratio was then gradually reduced until the cathode stoichiometric ratio reached 0.7. The current density was maintained at 200 mA / cm 2 The current density and cathode stoichiometry ratio of 0.7 were run for 5 min at 200 mA / cm 2 During the low current density operation, it is necessary to ensure that the single cell voltage of the fuel cell is greater than 0.05V. If the single cell voltage is lower than 0.05V, the cathode stoichiometric ratio can be appropriately increased to protect the battery.
[0117] Repeatedly load the fuel cell to a high current density of 200 mA / cm 2 and a cathode stoichiometric ratio of 0.7 for 5 min, respectively measuring the current density of the fuel cell at 100 mA / cm after the fuel cell runs for a second preset time. 2 , 1000mA / cm 2 , 2000mA / cm 2 The target voltages under the current density of are respectively used as the first target voltage, the second target voltage, and the third target voltage.
[0118] Determining a difference between the reference voltage and the target voltage; generating a recovery result of the fuel cell according to the difference;
[0119] After determining that the recovery result of the fuel cell is that the fuel cell has not been fully recovered, the fuel cell is operated at 200 mA / cm 2 The fuel cell is operated at a normal cathode stoichiometric ratio for 2 minutes at a small current density, and then the cathode stoichiometric ratio is gradually reduced to 0.7, so that the fuel cell is operated under an oxygen-deficient state for 5 minutes, and the above operation is repeated, and the reference voltage and the target voltage are compared, and a recovery result of the fuel cell is generated based on the comparison result, until it is determined that the recovery result of the fuel cell is a result of complete recovery of the fuel cell, or the number of times the recovery result of the fuel cell is generated is greater than a preset maximum number of times.
[0120] The fuel cell recovery method provided in this application has the following beneficial effects:
[0121] (1) Using available reactants in the fuel cell system to recover multiple reversible decays without additional piping control systems or inert gases, it has the advantages of simple and convenient operation;
[0122] (2) By operating at a high current density to generate a large gas flow and a large amount of condensed water, impurities that block the pores in the gas diffusion layer and adsorb on the catalyst surface can be removed, which is beneficial to constructing water and gas transmission channels and increasing the active reaction sites of the catalyst. At the same time, the low voltage under high current density also helps to reduce the oxides in the catalyst layer;
[0123] (3) By operating at low current density with oxygen deficiency, low voltage and hydrogen generated at the cathode can quickly reduce the oxides in the catalyst layer, effectively restoring the fuel cell.
[0124] The optional embodiments of the present application are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. A fuel cell recovery method, characterized in that: The fuel cell recovery method comprises: Obtaining a reference voltage of the fuel cell; Controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time, wherein the first preset current density is greater than a first preset current density threshold, and the first preset voltage is less than a first preset voltage threshold; reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density; measuring a target voltage of the fuel cell after the fuel cell has been running for the second preset time; The reference voltage and the target voltage are compared, and a recovery result of the fuel cell is generated based on the comparison result.
2. The fuel cell recovery method according to claim 1, characterized in that: The step of operating the fuel cell at a first preset current density and a first preset voltage for a first preset time includes: The current density of the fuel cell is increased to the first preset current density so that the operating voltage of the fuel cell is lower than the first preset voltage, and the fuel cell is controlled to operate at the first preset current density and the first preset voltage for a first preset time; the first preset time ranges from 10min to 20min.
3. The fuel cell recovery method according to claim 1, characterized in that: The step of reducing the cathode stoichiometric ratio of the fuel cell to a preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a second preset time at a second preset current density and in the oxygen-deficient state, wherein the second preset current density is less than the first preset current density, comprises: reducing the current density of the fuel cell from the first preset current density to the second preset current density; Setting the cathode stoichiometric ratio of the fuel cell to a second preset cathode stoichiometric ratio, and controlling the fuel cell to operate at the second preset cathode stoichiometric ratio and the second preset current density for a third preset time; reducing the cathode stoichiometric ratio of the fuel cell from the second preset cathode stoichiometric ratio to the preset cathode stoichiometric ratio so that the fuel cell reaches an oxygen-deficient state, and controlling the fuel cell to operate for a fourth preset time at the second preset current density and the oxygen-deficient state; The range of the third preset time is 0min-5min; the range of the fourth preset time is 0min-10min; the second preset time includes the third preset time and the fourth preset time.
4. The fuel cell recovery method according to claim 1, characterized in that: After operating the fuel cell at the first preset current density and the first preset voltage for a first preset time, the method further includes: The cathode stoichiometric ratio of the fuel cell is increased to a first preset cathode stoichiometric ratio, and the fuel cell is controlled to operate at the first preset current density for a fifth preset time; wherein the fifth preset time ranges from 0 min to 5 min.
5. The fuel cell recovery method according to claim 1, characterized in that: The step of obtaining a reference voltage of the fuel cell comprises: Obtaining a first reference voltage of the fuel cell at a first target current density; obtaining a second reference voltage of the fuel cell at a second target current density; obtaining a third reference voltage of the fuel cell at a third target current density; The first reference voltage, the second reference voltage, and the third reference voltage are determined as the reference voltages.
6. The fuel cell recovery method according to claim 1, characterized in that: Measuring a target voltage of the fuel cell after running for a second preset time includes: Repeat the steps of controlling the fuel cell to operate at a first preset current density and a first preset voltage for a first preset time, to controlling the fuel cell to operate at a second preset current density and an oxygen-deficient state for a second preset time; measuring a first target voltage of the fuel cell at the first target current density; measuring a second target voltage of the fuel cell at the second target current density; measuring a third target voltage of the fuel cell at the third target current density; The first target voltage, the second target voltage, and the third target voltage are determined as the target voltages.
7. The fuel cell recovery method according to claim 6, characterized in that: The comparing the reference voltage and the target voltage, and generating a recovery result of the fuel cell based on the comparison result, comprises: determining a difference between the reference voltage and the target voltage; A recovery result of the fuel cell is generated according to a difference between the reference voltage and the target voltage.
8. The fuel cell recovery method according to claim 7, characterized in that: The determining the difference between the reference voltage and the target voltage includes: A first difference between the first target voltage and the first reference voltage is determined; a second difference between the second target voltage and the second reference voltage is determined; and a third difference between the third target voltage and the third reference voltage is determined.
9. The fuel cell recovery method according to claim 8, characterized in that: The step of generating a recovery result of the fuel cell according to a difference between the reference voltage and the target voltage includes: When the first difference, the second difference, and the third difference are all smaller than a preset difference threshold, determining that the recovery result of the fuel cell is a result that the fuel cell is fully recovered; When any one of the first difference, the second difference, and the third difference is greater than or equal to the preset difference threshold, it is determined that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered.
10. The fuel cell recovery method according to claim 9, characterized in that: After determining that the recovery result of the fuel cell is a result that the fuel cell is not fully recovered, the method further includes: Controlling the fuel cell to operate at the second current density for a fifth preset time, wherein the fifth preset time ranges from 0 min to 10 min; Restoring the cathode stoichiometric ratio of the fuel cell to the second preset cathode stoichiometric ratio, and controlling the fuel cell to operate for a sixth preset time at the second preset cathode stoichiometric ratio; wherein the sixth preset time ranges from 0 min to 5 min, and the second preset cathode stoichiometric ratio is greater than the preset cathode stoichiometric ratio; Repeat the steps of reducing the cathode metering ratio of the fuel cell to a preset cathode metering ratio, comparing the reference voltage and the target voltage, and generating a recovery result of the fuel cell based on the comparison result, until it is determined that the recovery result of the fuel cell is a result of complete recovery of the fuel cell, or the number of times the recovery result of the fuel cell is generated is greater than a preset maximum number of times.
Citation Information
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Fuel cell control method, device, computer equipment, readable storage medium and program product
CN122781915A