Humidity control method and system of fuel cell, cell and device

Abstract

The invention discloses a humidity control method and system of a fuel cell, the cell and a device, and the control method comprises the following steps: in a working state, collecting pile temperature Tmonitor and air path humidity RHmonitor data in real time, and when it is monitored that the pile temperature Tmonitor reaches a preset target value Tset and the air path humidity RHmonitor does not reach a preset target humidity RHset, determining that the air path humidity RHmonitor does not reach the preset target humidity RHset; wherein the Tset and the RHset are set according to the current running current density, the ratio RHratio of the air path humidity RHmonitor to the target humidity RHset is calculated, the RHratio is compared with a lower limit threshold RHlowerlimit or an upper limit threshold RHupperlimit, the flow Qair of the air path is adjusted according to the comparison result, the flow Qair is set according to the current running current density, when the RHratio is smaller than the set lower limit threshold RHlowerlimit, the flow Qair is reduced; and when the RHratio is greater than a set upper limit threshold value RHupperlimit, the flow rate Qair is increased. The internal humidity stability of the membrane electrode is effectively guaranteed, the performance of a fuel cell engine is remarkably improved, the service life of the fuel cell engine is prolonged, and the membrane electrode has wide working condition adaptability.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a humidity control method, system, battery and device for a fuel cell. Background Art

[0002] With the growing global demand for clean energy, hydrogen fuel cells, as a highly efficient and environmentally friendly energy conversion device, have garnered widespread attention. The membrane electrode (MAE) is a key component in fuel cells, directly determining the output power of the fuel cell engine. However, the performance and lifespan of the MAE are significantly affected by the humidity environment within it.

[0003] In the existing technology, traditional fuel cell engine humidity control methods have many shortcomings. On the one hand, for different power points, basically similar temperature and humidity control parameters are set, ignoring the optimal temperature and humidity conditions required by the membrane electrode under different current densities. On the other hand, when the temperature of the fuel cell stack reaches the target value, if the humidity of the air path deviates, it cannot be accurately adjusted according to the actual situation, making the membrane electrode prone to humidity discomfort. For example, when the humidity of the air path is low, the proton exchange membrane is prone to drying out due to water loss, resulting in a decrease in proton conductivity, thereby reducing the performance of the fuel cell; when the humidity of the air path is too high, water is easily accumulated inside the membrane electrode, causing flooding, hindering gas diffusion, and also significantly reducing the performance of the fuel cell. At the same time, it also accelerates the attenuation of the membrane electrode. These problems have seriously restricted the promotion and application of fuel cell engines.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide a humidity control method, system, battery and device for a fuel cell.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The object of the present invention is to provide a method, system, battery and device for controlling humidity of a fuel cell.

[0007] In order to achieve the above object, a specific embodiment of the present invention provides the following technical solutions:

[0008] A method for controlling humidity of a fuel cell comprises the following steps:

[0009] In the working state, the stack temperature T is collected in real time monitor and air humidity RH monitor Data (preferably, the data collection interval is 100ms), when the stack temperature T monitorReach the preset target value T set The air humidity RH monitor The preset target humidity RH is not reached set When T set and RH set To set according to the current operating current density, calculate the air path humidity RH monitor and target humidity RH set The ratio RH ratio =RH monitor / RH set :

[0010] RH ratio With the lower threshold RH lowerlimit Or upper threshold RH upperlimit Compare and adjust the air flow Q according to the comparison results. air Adjust the flow rate Q air To set according to the current operating current density: when RH ratio Less than the set lower threshold RH lowerlimit When the flow rate Q is reduced air When RH ratio Greater than the set upper threshold RH upperlimit When increasing the flow rate Q air RH lowerlimit The value is selected from 0.85-0.95, RH upperlimit The value is selected from 1.05-1.15.

[0011] In one or more embodiments of the present invention, T set and RH set The settings are:

[0012] Current density is 0-0.5A / cm 2 Within the range, T set Range is 30-50℃, RH set Range is 50-70%;

[0013] Current density is 0.5-1.0A / cm 2 Within the range, T set Range is 40-60℃, RH set Range is 40-60%;

[0014] Current density is 1.0-1.5A / cm 2 Within the range, T set Range is 50-70℃, RH set Range is 30-50%;

[0015] Current density is 1.5-2.5A / cm 2 Within the range, Tset Range is 70-80℃, RH set The range is 20-40%.

[0016] In one or more embodiments of the present invention, the flow rate Q air The setting is, where the stoichiometric ratio (referring to the stoichiometric ratio of air) is:

[0017] Current density is 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is 2.8-3.4;

[0018] Current density is 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is 2.4-2.8;

[0019] Current density is 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is 2.0-2.4;

[0020] Current density is 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is 1.7-2.0.

[0021] In one or more embodiments of the present invention, reducing the flow rate Q air To reduce the air flow rate, reduce the air flow rate by 5%-15%, but not lower than the minimum input air flow rate.

[0022] In one or more embodiments of the present invention, the minimum input air flow rate is set according to the current operating current density:

[0023] Current density is 0-0.5A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.8;

[0024] Current density is 0.5-1.0A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.4;

[0025] Current density is 1.0-1.5A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.0;

[0026] Current density is 1.5-2.5A / cm 2 Within the range, Q airThe minimum input air flow rate is the flow rate corresponding to a metering ratio of 1.7.

[0027] In one or more embodiments of the present invention, the flow rate Q is increased air To: Increase the air flow rate by 5%-15%.

[0028] In one or more embodiments of the present invention, the stack temperature T is collected. monitor Data from a temperature sensor; and / or

[0029] Collect the air path humidity RH monitor The data is collected using a humidity sensor.

[0030] In one or more embodiments of the present invention, a humidity control system implements a humidity control method for a fuel cell.

[0031] In one or more embodiments of the present invention, a fuel cell includes a main body and a humidity control system disposed on the main body to control the humidity thereof.

[0032] In one or more embodiments of the present invention, the power device includes at least a power output device driven by a fuel cell.

[0033] Compared with the prior art, the humidity control method, system, battery, and device for the fuel cell of the present invention utilize humidity sensors and temperature sensors to monitor the air path humidity and stack temperature in real time. When the stack temperature reaches a preset target value but the air path humidity does not reach the preset target value, the air side flow rate is adjusted based on the ratio of the air humidity to the target humidity. When the ratio is below the lower threshold, the air flow rate is reduced to prevent the proton exchange membrane from drying out; when the ratio is above the upper threshold, the air flow rate is increased to prevent the membrane electrode from flooding. Through a precise adjustment mechanism, the internal humidity of the membrane electrode is effectively guaranteed to be stable, significantly improving the performance of the fuel cell engine and extending its service life. It also has a wide range of adaptability to working conditions and can be widely used in various fuel cell engine systems.

[0034] In addition, the solution of the present invention also achieves the following technical effects:

[0035] (1) Precise adaptation to operating conditions. Taking into full account the different requirements of the membrane electrode for humidity under different current densities, the control parameters are dynamically adjusted to ensure that the membrane electrode is in a humidity environment close to the optimal one under various operating conditions. From an electrochemical perspective, under low-current density conditions, increasing the target range of air path humidity can ensure that the proton exchange membrane maintains sufficient water content, maintains a high proton conductivity, and ensures the electrochemical activity of the fuel cell; under high-current density conditions, reducing the relative humidity range on the air side can effectively prevent the membrane electrode from being flooded, maintain the smoothness of gas diffusion, and ensure the normal kinetic process of the fuel cell reaction. This precise adaptation significantly improves the performance of the fuel cell engine under different operating conditions.

[0036] (2) High-precision humidity control. Utilizing real-time monitoring data and a precise adjustment strategy based on a set humidity ratio, the system can quickly and accurately respond to changes in air path humidity, preventing the membrane electrode from drying out or flooding, ensuring stable operation of the fuel cell engine, and extending the service life of the membrane electrode.

[0037] (3) Improve the stability and reliability of the fuel cell engine system. A stable and suitable humidity environment helps maintain the stability of the chemical reactions inside the fuel cell engine. When the membrane electrode humidity is within the ideal range, the output voltage fluctuation of the fuel cell is reduced and the power output is more stable. This not only improves the reliability of the fuel cell engine in practical applications, but also reduces the requirements for subsequent power conversion and storage equipment, reducing system costs. At the same time, stable humidity conditions can reduce the stress impact on various components of the fuel cell engine caused by sudden changes in humidity, thereby improving the durability of the entire system.

[0038] (4) Universal applicability. The method's dynamic adjustment mechanism and precise regulation strategy make it widely applicable. Fuel cell engines of different types and specifications, although different in structure and performance, all face the challenge of humidity control. By establishing a universal control logic and dynamic adjustment model, the present invention can flexibly adjust control parameters according to the membrane electrode characteristics and operating conditions of different fuel cell engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 is a schematic diagram of a fuel cell engine humidity control method according to an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of the fuel cell engine humidity control method in Example 1 of the present invention;

[0042] Figure 3 Schematic diagram of a fuel cell engine humidity control method in Example 2 of the present invention;

[0043] Figure 4 Schematic diagram of a fuel cell engine humidity control method in Example 3 of the present invention;

[0044] Figure 5 The average voltage and RH in Comparative Example 1 of the present inventionratio Change curve;

[0045] Figure 6 The average voltage and RH in Comparative Example 2 of the present invention ratio Change curve;

[0046] Figure 7 The average voltage and RH in Comparative Example 3 of the present invention ratio Change curve. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0048] Example 1

[0049] In this embodiment, the fuel cell engine operates at different current densities under different operating conditions, including temperature parameters, humidity parameters, and air stoichiometric ratio parameters. 2 Within the range, T set 40℃, RH set 60%, Q air The corresponding metering ratio is 3.2; at 0.5-1.0A / cm 2 Within the range, T set 50℃, RH set 50%, Q air The corresponding metering ratio is 2.6; at 1.0-1.5A / cm 2 Within the range, T set 60℃, RH set 40%, Q air The corresponding metering ratio is 2.2; at 1.5-2.5A / cm 2 Within the range, T set 75℃, RH set 30%, Q air The corresponding metering ratio is 1.9.

[0050] The humidity control method during the operation of the fuel cell engine is as follows: Figure 2 As shown, the stack temperature T is continuously collected in real time during operation. monitor and air humidity RH monitor Data, when the stack temperature T is monitored monitor Reach the preset target value T set The air humidity RHmonitor Target RH not reached set Calculate the current air humidity RH monitor and target humidity RH set The ratio RH ratio If RH ratio If it is less than 0.9, the air flow rate is reduced to 95% of the original air flow rate, that is, between 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 3.04, which meets the minimum flow requirement in this range, that is, the metering ratio is not less than 2.8; in the range of 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.47, which meets the minimum flow requirement in this range, that is, the metering ratio is not less than 2.4; in the range of 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.09, which meets the minimum flow requirement in this range, that is, the metering ratio is not less than 2.0; in the range of 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 1.81 to meet the minimum flow requirement in this range, that is, the metering ratio is not less than 1.7. ratio If it is greater than 1.1, the air flow rate on the increased side is 105% of the original air flow rate, that is, in the range of 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 3.36; in the range of 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.73; at 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.31; at 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.0. ratio In the range of 0.9-1.1, the air side flow rate is adjusted to the original input parameters, and the fuel cell engine operates normally, that is, there is no need to adjust Q air The corresponding metering ratio should be adjusted.

[0051] Example 2

[0052] In this embodiment, the fuel cell engine operates at different current densities under different operating conditions, including temperature parameters, humidity parameters, and air stoichiometric ratio parameters. 2 Within the range, T set 50℃, RH set 70%, Q airThe corresponding metering ratio is 3.4; at 0.5-1.0A / cm 2 Within the range, T set 60℃, RH set 60%, Q air The corresponding metering ratio is 2.8; at 1.0-1.5A / cm 2 Within the range, T set 70℃, RH set 50%, Q air The corresponding metering ratio is 2.4; at 1.5-2.5A / cm 2 Inside, T set Range is 80℃, RH set 40%, Q air The corresponding stoichiometric ratio is 2.0.

[0053] The humidity control method during the operation of the fuel cell engine is as follows: Figure 3 As shown, the stack temperature T is continuously collected in real time during operation. monitor and air humidity RH monitor Data, when the stack temperature T is monitored monitor Reach the preset target value T set The air humidity RH monitor Target RH not reached set Calculate the current air humidity RH monitor and target humidity RH set The ratio RH ratio If RH ratio If it is less than 0.85, the air flow rate is reduced to 85% of the original air flow rate, that is, between 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.89, which meets the minimum flow requirement in this range, that is, the metering ratio is not less than 2.8; in the range of 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.38, which does not meet the minimum flow requirement of this interval, that is, the metering ratio is not less than 2.4, so the metering ratio is set to 2.4; in 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.04 to meet the minimum flow requirement in this range, that is, the metering ratio is not less than 2.0; in the range of 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 1.7 to meet the minimum flow requirement in this interval, that is, the metering ratio is not less than 1.7. ratio If it is greater than 1.15, the air flow rate on the increased side is 115% of the original air flow rate, that is, between 0-0.5A / cm 2 Within the range, Qair The corresponding metering ratio is adjusted to 3.9; at 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 3.22; at 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.76; at 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.3. ratio In the range of 0.85-1.15, the air side flow rate is adjusted to the original input parameters, and the fuel cell engine operates normally, that is, there is no need to adjust Q air The corresponding metering ratio should be adjusted.

[0054] Example 3

[0055] In this embodiment, the fuel cell engine operates at different current densities under different operating conditions, including temperature parameters, humidity parameters, and air stoichiometric ratio parameters. 2 Within the range, T set 30℃, RH set 50%, Q air The corresponding metering ratio is 3.0; at 0.5-1.0A / cm 2 Within the range, T set 40℃, RH set 40%, Q air The corresponding metering ratio is 2.5; at 1.0-1.5A / cm 2 Within the range, T set 50℃, RH set 30%, Q air The corresponding metering ratio is 2.1; at 1.5-2.5A / cm 2 Within the range, T set 70℃, RH set 40%, Q air The corresponding metering ratio is 1.8.

[0056] The humidity control method during the operation of the fuel cell engine is as follows: Figure 4 As shown, the stack temperature T is continuously collected in real time during operation. monitor and air humidity RH monitor Data, when the stack temperature T is monitored monitor Reach the preset target value T set The air humidity RH monitor Target RH not reached set Calculate the current air humidity RH monitor and target humidity RH setThe ratio RH ratio If RH ratio If it is less than 0.95, the air flow rate is reduced to 90% of the original air flow rate, that is, between 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.85 to meet the minimum flow requirement in this range, that is, the metering ratio is not less than 2.8; in the range of 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.38, which does not meet the minimum flow requirement of this interval, that is, the metering ratio is not less than 2.4, so the metering ratio is set to 2.4; in 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.0 to meet the minimum flow requirement in this range, that is, the metering ratio is not less than 2.0; in the range of 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 1.71 to meet the minimum flow requirement in this range, that is, the metering ratio is not less than 1.7. ratio If it is greater than 1.05, the air flow rate on the increased side is 105% of the original air flow rate, that is, in the range of 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 3.15; in the range of 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.63; at 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 2.21; at 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is adjusted to 1.89. ratio If the air side flow rate is within the range of 0.95-1.05, the fuel cell engine can operate normally without adjusting Q. air The corresponding metering ratio should be adjusted.

[0057] Comparative Example 1

[0058] The same as Example 1, except that the air flow rate during the operation of the fuel cell engine is always output according to the set value, even if the air humidity RH monitor and target humidity RH set The ratio RH ratio It is not within the range of 0.9 to 1.1, nor is it effective for the air side flow rate Q air Make adjustments.

[0059] By selecting 1.0A / cm 2The measured data of the fuel cell engine during operation are shown below. The average voltage of this comparative example and Example 1 is varied with RH. ratio The change curves are compared, and the results are as follows Figure 5 As shown. In RH ratio Within the time range below 0.9, the average voltages of both this comparative example and Example 1 show a slow decline phenomenon, but the average voltage decline of Example 1 is smaller than that of this comparative example. And after a period of time, the average voltage of Example 1 begins to gradually recover to 0.720~0.721V in the previous state, while the average voltage in this comparative example gradually decreases to 0.716~0.717V. This is precisely because the actual humidity inside the engine is too low at this time, causing the membrane electrode inside the fuel cell stack to be dry, so the average voltage begins to slowly decline. However, Example 1 utilizes real-time monitoring data and a precise adjustment strategy based on a set humidity ratio, which can quickly and accurately respond to changes in air path humidity. At this time, the air side flow rate is reduced, avoiding the problem of continuous over-drying of the membrane electrode, thereby reducing the output voltage fluctuation of the fuel cell and gradually returning the average voltage to a normal state, ensuring the stable operation of the fuel cell engine.

[0060] Comparative Example 2

[0061] The same as Example 2, except that the air flow rate during the operation of the fuel cell engine is always output according to the set value, even if the air humidity RH monitor and target humidity RH set The ratio RH ratio It is not within the range of 0.85 to 1.15, nor is it effective for the air side flow rate Q air Make adjustments.

[0062] By selecting 1.5A / cm 2 The measured data of the fuel cell engine during operation are shown below. The average voltage in this comparative example and Example 2 is varied with RH. ratio The change curves are compared, and the results are as follows Figure 6 As shown. In RH ratioIn the time range above 1.15, the average voltages of both this comparative example and Example 2 show a slow decline phenomenon, but the average voltage decline of Example 2 is smaller than that of this comparative example. And after a period of time, the average voltage of Example 2 begins to gradually recover to 0.697~0.698V in the previous state, while the average voltage in this comparative example gradually decreases to 0.693~0.694V. This is precisely because the actual humidity inside the engine is too high at this time, causing the membrane electrode inside the fuel cell stack to be wet, so the average voltage begins to slowly decline. However, Example 2 utilizes real-time monitoring data and a precise adjustment strategy based on a set humidity ratio, which can quickly and accurately respond to changes in air path humidity. At this time, the air side flow is increased to avoid the problem of continuous wetness or even partial flooding of the membrane electrode, thereby reducing the output voltage fluctuation of the fuel cell and gradually restoring the average voltage to a normal state, ensuring the stable operation of the fuel cell engine.

[0063] Comparative Example 3

[0064] The same as Example 3, except that the air flow rate during the operation of the fuel cell engine is always output according to the set value, even if the air humidity RH monitor and target humidity RH set The ratio RH ratio It is not within the range of 0.95 to 1.05, nor is it effective for the air side flow rate Q air Make adjustments.

[0065] By selecting 2.0A / cm 2 The measured data of the fuel cell engine during operation are shown below. The average voltage in this comparative example and Example 3 is varied with RH. ratio The change curves are compared, and the results are as follows Figure 7 As shown. In RH ratio Within the time range higher than 1.05, the average voltages of both this comparative example and Example 3 show a slow decline phenomenon, but the average voltage decline of Example 3 is smaller than that of this comparative example. And after a period of time, the average voltage of Example 3 begins to gradually recover to 0.649~0.650V in the previous state, while the average voltage in this comparative example gradually decreases to 0.645~0.647V. This is precisely because the actual humidity inside the engine is too high at this time, causing the membrane electrode inside the fuel cell stack to be wet, so the average voltage begins to slowly decline. However, Example 3 utilizes real-time monitoring data and a precise adjustment strategy based on a set humidity ratio, which can quickly and accurately respond to changes in air path humidity. At this time, the air side flow is increased to avoid the problem of continuous wetness or even partial flooding of the membrane electrode, thereby reducing the output voltage fluctuation of the fuel cell and gradually restoring the average voltage to a normal state, ensuring the stable operation of the fuel cell engine.

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0067] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for controlling humidity of a fuel cell, comprising the following steps: In the working state, the stack temperature T is collected in real time monitor and air humidity RH monitor Data, when the stack temperature T is monitored monitor Reach the preset target value T set The air humidity RH monitor The preset target humidity RH is not reached set When T set and RH set To set according to the current operating current density, calculate the air path humidity RH monitor and target humidity RH set The ratio RH ratio =RH monitor / RH set : RH ratio With the lower threshold RH lowerlimit Or upper threshold RH upperlimit Compare and adjust the air flow Q according to the comparison results. air Adjust the flow rate Q air To set according to the current operating current density: when RH ratio Less than the set lower threshold RH lowerlimit When the flow rate Q is reduced air When RH ratio Greater than the set upper threshold RH upperlimit When increasing the flow rate Q air .

2. The method for controlling humidity of a fuel cell according to claim 1, wherein: The T set and RH set The settings are: Current density is 0-0.5A / cm 2 Within the range, T set Range is 30-50℃, RH set Range is 50-70%; Current density is 0.5-1.0A / cm 2 Within the range, T set Range is 40-60℃, RH set Range is 40-60%; Current density is 1.0-1.5A / cm 2 Within the range, T set Range is 50-70℃, RH set The range is 30-50%; the current density is 1.5-2.5A / cm 2 Within the range, T set Range is 70-80℃, RH set The range is 20-40%.

3. The method for controlling humidity of a fuel cell according to claim 1, wherein: The flow rate Q air The setting is, where the stoichiometric ratio is: Current density is 0-0.5A / cm 2 Within the range, Q air The corresponding metering ratio is 2.8-3.4; Current density is 0.5-1.0A / cm 2 Within the range, Q air The corresponding metering ratio is 2.4-2.8; Current density is 1.0-1.5A / cm 2 Within the range, Q air The corresponding metering ratio is 2.0-2.4; Current density is 1.5-2.5A / cm 2 Within the range, Q air The corresponding metering ratio is 1.7-2.

0.

4. The method for controlling humidity of a fuel cell according to claim 1, wherein: The reduced flow rate Q air To reduce the air flow rate, reduce the air flow rate by 5%-15%, but not lower than the minimum input air flow rate.

5. The method for controlling humidity of a fuel cell according to claim 4, wherein: The minimum input air flow rate is set according to the current operating current density: Current density is 0-0.5A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.8; Current density is 0.5-1.0A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.4; Current density is 1.0-1.5A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to the metering ratio of 2.0; Current density is 1.5-2.5A / cm 2 Within the range, Q air The minimum input air flow rate is the flow rate corresponding to a metering ratio of 1.

7.

6. The method for controlling humidity of a fuel cell according to claim 1, wherein: The increased flow rate Q air To: Increase the air flow rate by 5%-15%.

7. The method for controlling humidity of a fuel cell according to claim 1, wherein: Collect the stack temperature T monitor Data from temperature sensors; and / or Collect the air path humidity RH monitor The data is collected using a humidity sensor.

8. A humidity control system, implementing the humidity control method for a fuel cell according to any one of claims 1 to 7.

9. A fuel cell comprising a main body and the humidity control system according to claim 8 provided in the main body to control the humidity thereof.

10. A power plant comprising at least a power output device driven by the fuel cell according to claim 9.

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