CN115939467B - Method for controlling water content of fuel cell stack in fuel cell system - Google Patents

Abstract

This application provides a method for controlling the water content of the fuel cell stack in a fuel cell system. According to the changing requirements of the stack water content in the fuel cell system, at least one characteristic curve is determined; the characteristic curve represents the output voltage of the fuel cell stack as the output The changing relationship of current; among them, the power control subsystem monitors the output voltage and current of the stack in real time, and automatically adjusts the output electric energy of the stack to keep the voltage and current output by the stack within the described characteristic curve; when the water content of the stack is required When increasing, reduce the voltage value of the characteristic curve; when the stack water content needs to be reduced, increase the voltage value of the characteristic curve. Under certain operating conditions, the lower the voltage of the characteristic curve, the greater the output current of the stack, and the more water is generated, thus increasing the water content of the stack; conversely, the higher the voltage of the characteristic curve, the smaller the output current of the stack, and the more water is generated. less, thus reducing the water content of the stack.

Description

Method for controlling water content of fuel cell stack in fuel cell system

Technical field

The present application relates to the technical field of fuel cells, and specifically relates to a method for controlling the water content of a fuel cell stack in a fuel cell system.

Background technique

The fuel cell system includes the fuel cell stack, subsystems such as anode gas supply, cathode gas supply and cooling management that control the reaction parameters of the fuel cell, and the power control subsystem that controls the output power of the fuel cell. Humidity during fuel cell stack operation affects the overall performance of the stack and needs to be maintained at an appropriate level. Inappropriate operating parameters of the fuel cell will cause the water content inside the stack to be too low or too high, causing the membrane electrode to dry out or be flooded, causing the stack performance to decline.

The existing technology jointly controls the specific working condition parameters of the anode gas supply, cathode gas supply, coolant and other fluids of the fuel cell stack through the cathode gas supply subsystem, anode gas supply subsystem and cooling management subsystem, and through the power control subsystem The system uses a target current control strategy to control the output current and water production of the fuel cell stack, thereby controlling the water content of the fuel cell stack. However, since the cathode gas supply subsystem, anode gas supply subsystem, cooling management subsystem and power control subsystem need to coordinate with each other, the load changing rate is low and the response to output power changes is slow.

In order to improve the dynamic response speed of the fuel cell system's output power changes, a characteristic curve control strategy is proposed, that is, first setting a characteristic curve of the relationship between the output voltage of the fuel cell stack and the change of the output current, and the power control subsystem monitors the stack in real time. Output voltage and current, and automatically adjust the output power of the stack to keep the voltage and current output by the stack on the described characteristic curve. However, this control strategy only guarantees the relationship between the output voltage and output current of the fuel cell stack, and does not directly control the output current of the fuel cell stack at the target current. Therefore, it cannot directly control the fuel cell stack like the existing technology. output current, water production and moisture content.

Therefore, it is necessary to provide a new solution for controlling the water content of the fuel cell stack in the fuel cell system in order to improve the characteristic control strategy of the fuel cell system output dynamic response speed.

Contents of the invention

In view of this, embodiments of this specification provide a method for controlling the water content of the fuel cell stack in the fuel cell system based on the characteristic curve control strategy, which is applied to the process of water balance in the operation of the fuel cell stack.

The embodiments of this specification provide the following technical solutions:

Embodiments of this specification provide a method for controlling the water content of a fuel cell stack in a fuel cell system. The method for controlling the water content of a fuel cell stack in a fuel cell system includes:

Determine at least one characteristic curve; the characteristic curve represents the relationship between the output voltage of the fuel cell stack and the output current as the operating conditions change, under the control of the power control subsystem; wherein, the power control subsystem monitors in real time The stack outputs voltage and current, and automatically adjusts the stack's output electric energy to keep the voltage and current output by the stack on the described characteristic curve;

According to the changing demand of stack water content in the fuel cell system, the characteristic curve is moved up or down; by moving the characteristic curve upward, the output voltage of the fuel cell stack is increased, thereby reducing the output current of the fuel cell stack and reducing generation Water, reduce the water content of the stack, or move the characteristic curve downward to reduce the output voltage of the fuel cell stack, thereby increasing the output current of the fuel cell stack, increasing the generated water, and increasing the water content of the stack;

Among them, the upward-moving characteristic curve has a fuel cell stack output voltage higher than the current characteristic curve; the downward-moving characteristic curve has a lower fuel cell stack output voltage than the current characteristic curve.

Embodiments of this specification also provide a device for controlling the water content of the fuel cell stack in the fuel cell system. The device for controlling the water content of the fuel cell stack in the fuel cell system includes:

Obtaining module, used to determine at least one characteristic curve; the characteristic curve represents the relationship between the output voltage of the fuel cell stack and the output current as the working conditions change and under the control of the power control subsystem; wherein, the power The control subsystem monitors the output voltage and current of the stack in real time, and automatically adjusts the output power of the stack to keep the voltage and current output by the stack on the characteristic curve;

The operation module is used to move the characteristic curve up or down according to the changing requirements of the stack water content in the fuel cell system; by moving the characteristic curve upward, the fuel cell stack output voltage is increased, thereby reducing the fuel cell stack Output current, reduce water generation, and reduce the water content of the stack, or move the characteristic curve downward to reduce the output voltage of the fuel cell stack, thereby increasing the output current of the fuel cell stack, increasing water generation, and increasing the water content of the stack;

Among them, the upward-moving characteristic curve has a fuel cell stack output voltage higher than the current characteristic curve; the downward-moving characteristic curve has a lower fuel cell stack output voltage than the current characteristic curve.

Embodiments of this specification also provide a system for controlling the water content of a fuel cell stack in a fuel cell system, including a memory, a processor, and a computer program. The computer program is stored in the memory, and the processor runs the The computer program executes the method for controlling the water content of the fuel cell stack in the fuel cell system in any technical solution of the embodiments of this specification.

Embodiments of this specification also provide a readable storage medium, which stores a computer program. When the computer program is executed by a processor, it is used to implement the fuel cell in any technical solution of the embodiments of this specification. Method for controlling the water content of fuel cell stacks in the system.

Compared with the existing technology, the beneficial effects achieved by at least one of the above technical solutions adopted in the embodiments of this specification at least include:

The fuel cell system is based on the characteristic curve operation control method, which has the advantage of fast response to changes in output power. By moving the current characteristic curve up or down, the stack output voltage and current are changed so that the stack output voltage and current run at a real-time Generated up/down shift characteristic curve. When the water content of the stack needs to be increased, reduce the voltage value of the characteristic curve; when the water content of the stack needs to be reduced, increase the voltage value of the characteristic curve without changing the specific working conditions of anode gas supply, cathode gas supply, coolant and other fluids. Under the conditions of various parameters, the output current of the stack and the reactants consumed can be changed, thereby affecting the actual gas supply metering ratio, etc., and adjusting the water content of the stack.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of various subsystems related to the operation of a fuel cell stack in this application;

Figure 2 is a schematic diagram of various characteristic curves of the fuel cell stack operation in this application;

Figure 3 is a flow chart of a method for controlling the water content of a fuel cell stack in a fuel cell system in this application;

Figure 4 is a schematic diagram of a control device for water content of a fuel cell stack in a fuel cell system in this application;

Figure 5 is a schematic structural diagram of a system for controlling the water content of a fuel cell stack in a fuel cell system in this application.

Detailed ways

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following describes the implementation of the present application through specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. This application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, as long as there is no conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

To illustrate, the following describes various aspects of embodiments that are within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is illustrative only. Based on this application, those skilled in the art will appreciate that one aspect described herein can be implemented independently of any other aspect, and that two or more of these aspects can be combined in various ways. For example, apparatuses may be implemented and/or methods practiced using any of the numbers and aspects set forth herein. Additionally, such apparatus may be implemented and/or methods practiced using other structures and/or functionality in addition to one or more of the aspects set forth herein.

It should also be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic concept of the present application. The drawings only show the components related to the present application and are not based on the number, shape and number of components during actual implementation. Dimension drawing, in actual implementation, the type, quantity and proportion of each component can be arbitrarily changed, and the component layout type may also be more complex.

Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, one skilled in the art will understand that practices may be practiced without these specific details.

There is a characteristic curve control strategy to improve the dynamic response speed of the fuel cell system's output power change. That is, first set a characteristic curve of the relationship between the output voltage of the fuel cell stack and the change of the output current, and the power control subsystem monitors the stack in real time. Output voltage and current, and automatically adjust the output power of the stack to keep the voltage and current output by the stack on the described characteristic curve. However, this control strategy only guarantees the relationship between the output voltage and output current of the fuel cell stack and does not directly control the output current of the fuel cell stack at the target current. Therefore, it cannot directly control the output current and water content of the fuel cell stack. Production volume and moisture content.

In response to this problem, the embodiment of this specification proposes a control scheme for the water content of the fuel cell stack in the fuel cell system: the fuel cell system operates based on the characteristic curve control strategy. During the operation of the fuel cell system, the specific characteristic curve is based on the electric current. The power control subsystem executes the characteristic curve control strategy based on the real-time generated characteristic curve, that is, monitors the voltage and current output by the stack in real time, and adjusts the output electric energy of the stack to make the stack output The voltage and current remain on this real-time generated characteristic curve (see the up/down shift characteristic curve in Figure 2).

Therefore, when the water content of the stack needs to be increased, the voltage value of the characteristic curve is reduced; when the water content of the stack needs to be reduced, the voltage value of the characteristic curve is increased. Under normal operating conditions of the fuel cell stack, that is, during the operation of the fuel cell system, the various working conditions parameters are sufficient to meet the energy supply of the stack output voltage and current, and the various working condition parameters do not need to be adjusted. The lower the characteristic curve voltage, the fuel The greater the output current of the battery stack, the more water is generated, thereby increasing the water content of the fuel cell stack; conversely, the higher the characteristic curve voltage, the smaller the output current of the fuel cell stack is, and the less water is generated, thus reducing the Moisture content.

When the stack water content changes and the demand remains unchanged, the currently used characteristic curve does not need to be adjusted. The power control subsystem monitors the voltage and current output by the stack in real time, and adjusts the stack output power to make the fuel cell stack output voltage and the current remains on the current characteristic curve.

Therefore, under the characteristic curve control strategy, the output voltage and current of the fuel cell stack can respond quickly with rapid changes in the anode gas supply, cathode gas supply, and coolant, and the fuel cell electricity can be generated in real time according to the changing needs of the stack water content. The stack output voltage and current need to comply with the characteristic curve, so that the stack water generation rate and water content can be controlled and adjusted, and the stack water content can be adjusted. The fuel cell system in the embodiment of this specification adopts a characteristic curve control strategy to achieve rapid response to dynamic changes in output power. In order to solve the problem that this control method cannot directly control the output current value and adjust the water content of the fuel cell stack, by moving up/down Characteristic curve is used to adjust the output current of the fuel cell stack, the reactant consumption rate, and the water generation rate, and thereby adjust the water content in the fuel cell stack.

The following describes the technical solutions provided by each embodiment of the present application with reference to the accompanying drawings.

As shown in FIG. 3 , a method for controlling the water content of a fuel cell stack in a fuel cell system according to an embodiment of this specification includes steps S310 to S320. Step S310: Determine at least one characteristic curve; the characteristic curve represents the relationship between the output voltage of the fuel cell stack and the output current under the control of the power control subsystem as the working conditions change; wherein, the power control subsystem The system monitors the output voltage and current of the stack in real time and automatically adjusts the output power of the stack to keep the voltage and current output by the stack on the characteristic curve. Step S320: Move the characteristic curve upward or downward according to the changing requirements of the stack water content in the fuel cell system; by moving the characteristic curve upward, the fuel cell stack output voltage is increased, thereby reducing the fuel cell stack output current. , reduce the generated water, reduce the stack water content, or move the characteristic curve downward to reduce the fuel cell stack output voltage, thereby increasing the fuel cell stack output current, increasing the generated water, and increasing the stack water content; among them, the upward shift characteristic The curve has a higher fuel cell stack output voltage than the current characteristic curve; the downwardly shifted characteristic curve has a lower fuel cell stack output voltage than the current characteristic curve.

Specifically, the fuel cell system includes a fuel cell stack, and an anode gas supply subsystem that provides hydrogen as fuel for the fuel cell stack. The subsystem includes a hydrogen supply valve (as a supply source of high-pressure hydrogen), a circulation pump or an injector. (resending the remaining hydrogen discharged from the anode into the stack for recycling), water vapor separator (separating the liquid water droplets in the anode exhaust gas, protecting the normal operation of the circulation pump or ejector) and one-way valve (limiting the high-pressure hydrogen from The counterflow of the circulation pump to the water vapor separator ensures the anode gas); the cathode air supply subsystem provides air as an oxidant for the fuel cell stack. This subsystem includes an air compressor (as a supply source of compressed air), an intercooler ( Cooling the air that has been heated up under pressure), humidifier (using the hot and humid air discharged from the stack to increase the humidity of the air entering the stack, so that the stack membrane electrodes can operate under appropriate humidity conditions and improve the stack's operating performance and lifespan ) and back pressure valve (to limit exhaust gas emissions to increase cathode pressure and improve stack operating performance); a cooling management subsystem that provides coolant to the fuel cell stack to control the stack operating temperature. This subsystem includes a cooling pump (as The power source for coolant circulation), proportional valve (distributes the high-temperature coolant discharged from the stack to the deionizer and radiator), deionizer (uses materials such as ion exchange resin to absorb impurity ions in the coolant to reduce The ion concentration in the coolant reduces the corrosiveness and conductivity of the coolant in the system), the radiator and the radiator fan (the radiator fan drives the air to flow through the radiator to cool the high-temperature coolant flowing in the radiator, and then returns to the cooling pump to provide cooling for the stack). In some embodiments, the power control subsystem is a fuel cell stack output DC transformer, using a switching DCDC.

Based on the various subsystems related to regulating the water content of the stack in the fuel cell system, the voltage and current output by the stack are monitored in real time through the power control subsystem, and the output power of the stack is automatically adjusted to keep the voltage and current output by the stack at the same characteristic. On the curve, this characteristic curve represents the relationship between the output voltage of the fuel cell stack and the output current under the control of the power control subsystem as the working conditions change.

The electric energy output by the electrochemical reaction in the stack is related to the operating parameters such as reactant concentration, catalyst status, reaction pressure, etc. The same stack uses different working parameters, which will change the voltage or current output by the stack. In some embodiments, the fuel cell stack operates with different metering ratios, causing the stack output voltage and current to change. Therefore, through the characteristic curves of different voltage and current points, the metering ratio of the stack operation can be changed.

Therefore, the embodiments of this specification are based on the characteristic curve operation mode and self-judge the need to reduce/increase the stack water content according to the control instructions of the fuel cell system or the operating process of the fuel cell system, that is, the demand for stack water content in the fuel cell system changes. Move the current characteristic curve up or down to generate an upward shift characteristic curve or a downward shift characteristic curve in real time. By moving the characteristic curve upward, the fuel cell stack output voltage is increased, thereby reducing the fuel cell stack output current. Reduce the generated water and reduce the stack water content, or move the characteristic curve downward to reduce the fuel cell stack output voltage, thereby increasing the fuel cell stack output current, increasing the generated water, and increasing the stack water content. In some embodiments, a relatively low frequency is used to adjust the characteristic curve to achieve an upward or downward shift of the characteristic curve, thereby realizing stack operation without changing the specific working conditions parameters of fluids such as anode gas supply, cathode gas supply and coolant. Changes in the output current and consumed reactants will affect the actual gas supply metering ratio, etc., and realize the adjustment of the water content of the stack.

As shown in the example of Figure 2, if the current characteristic curve is the reference characteristic curve, moving the reference characteristic curve up or down can generate an upward movement characteristic curve or a downward movement characteristic curve in real time: the upward movement characteristic curve is relative to the current characteristic curve With a high voltage, the output current of the stack is reduced, thereby reducing the amount of water generated; when the downward-moving characteristic curve has a low voltage relative to the current characteristic curve, the output current of the stack is increased, thereby increasing the amount of water generated.

In some embodiments, the characteristic curve is moved up or down according to the changing requirements of the stack water content in the fuel cell system, including: if the fuel cell system is set to reduce the stack water content, according to the current characteristic curve , move the reference characteristic curve upward and the degree of upward movement to generate an upward movement characteristic curve in real time. Alternatively, if the fuel cell system is set to increase the water content of the stack, a downward shift characteristic curve is generated in real time based on the current characteristic curve, the downward shift reference characteristic curve and the downward shift degree.

In some embodiments, aiming at the goals of long-term stable operation of the stack, high-performance output, high-reliability operation, and low-cost maintenance, under preset working conditions, the influence of the operation strategy and parameters is considered, and the test samples are tested on the test bench. Based on the running and debugging results, the current characteristic curve obtained by optimization is as shown in the reference characteristic curve F in Figure 2. The reference characteristic curve corresponds to the changing range of the stack output current from 0 to 100%, and the corresponding changing range of the stack output voltage from 400 to 300V. The expression is V=F=aI+b, a and b are coefficients. In other embodiments, the current characteristic curve may not be a reference characteristic curve but may correspond to a characteristic curve under specific operating conditions.

Based on the changing relationship of the characteristic curve corresponding to the stack output voltage and current, if the fuel cell system is set to reduce the water content of the stack, an upward shift characteristic curve is generated based on the baseline characteristic curve, the upward shift baseline characteristic curve, and the degree of shift. Specifically, when the working conditions do not change, the current characteristic curve is moved upward. By moving the characteristic curve upward to the upwardly shifted characteristic curve generated in real time, the output voltage of the fuel cell stack is increased, and the output voltage is increased. As the current decreases, less water is produced. This upward-shifted reference characteristic curve has the highest fuel cell stack output voltage, which is discovered through a large number of experiments and characteristic curve operation rules, as detailed below. The degree of upward movement includes the degree of deviation from the reference characteristic curve and the stack output voltage/current corresponding to the upward movement of the reference characteristic curve during the upward movement of the characteristic curve.

In some embodiments, the upward-shifting reference characteristic curve U required to generate the upward-shifting characteristic curve in real time is designed to quickly and effectively reduce the water content of the stack while limiting the impact on stack performance and reliability. Based on the stack operating characteristics, through The running and debugging results of the test sample on the test bench are optimized. In this example, the variation range of the stack output current is 0 to 100%, and the corresponding stack output voltage is on the upward-shifting reference characteristic curve U. Its corresponding expression is V=U=cI+d, and its range is 420 to 330V. ; c, d are coefficients.

If the fuel cell system is set to increase the water content of the stack, a downward shift characteristic curve is generated in real time based on the baseline characteristic curve, the downward shift baseline characteristic curve, and the downward shift degree. Specifically, when the working conditions do not change, the current characteristic curve is moved downward. By moving the characteristic curve downward to a shifted characteristic curve generated in real time, the output voltage of the fuel cell stack is reduced and the output current is increased. , the generated water increases. Similarly, the downward-shifted reference characteristic curve has the lowest fuel cell stack output voltage, which is found through a large number of experiments and the operating rules of the characteristic curve, as detailed below. The degree of downward shift includes the degree of deviation from the reference characteristic curve and the stack output voltage/current corresponding to the downwardly shifted reference characteristic curve during the downward shift operation of the characteristic curve.

Similarly, in this example, the variation range of the stack output current is 0 to 100%, and the corresponding stack output voltage is on the downward-shifting reference characteristic curve D, which corresponds to the expression V=D=eI+f, and its range is 380 ~270V; e and f are coefficients.

Therefore, during the operation of the stack, the target humidity value is R0 (65% in this example), the actual measured value is R1 (for example, 30~90%), and the deviation coefficient is defined as θ=0.2*(R1-65%). The deviation The coefficient only represents the relationship between relative changes in humidity and is not limited to a specific value. When changing the operating relative humidity of the stack, when θ>0, the current characteristic curve moves upward to a real-time generated upward characteristic curve S2, specifically S2=Uθ+F(1-θ), which is higher than the reference characteristic curve F, In order to achieve smaller output current, reduce the moisture generated inside the stack, thereby reducing its relative humidity;

When θ<0, the current characteristic curve moves downward to a real-time generated downward characteristic curve S2. Specifically, S2=D|θ|+F(1-|θ|), which is lower than the reference characteristic curve F to achieve a better Large output current increases the amount of moisture generated inside the stack, thereby increasing its relative humidity.

In some embodiments, an upward shift reference characteristic curve and a downward shift reference characteristic curve are determined by operating the fuel cell system under various preset operating conditions; the upper shift reference characteristic curve and the downward shift reference characteristic curve limit each The characteristic curve corresponds to the range of the relationship between the stack output voltage and the output current. The upward-moving reference characteristic curve has the highest stack output voltage, and the downward-moving reference characteristic curve has the lowest stack output voltage.

Specifically, according to various preset working conditions of the stack electrochemical reaction, the highest and lowest operating range of the stack output voltage can be determined. Based on the stack output current and voltage conforming to the characteristic curve law, there is a stack output There is a characteristic curve corresponding to the highest voltage, such as moving the reference characteristic curve upward; at the same time, there is a characteristic curve corresponding to the lowest output voltage of the stack, such as moving the reference characteristic curve downward. It is determined through experiments that multiple characteristic curves corresponding to the stack output voltage and current can be generated between the upward-shifted reference characteristic curve and the downward-shifted reference characteristic curve.

In some embodiments, the preset working conditions corresponding to the stack output voltage and current include various working condition parameters of the stack operation, wherein the working condition parameters include the gas supply pressure, flow rate, respectively corresponding to the anode and cathode of the fuel cell. Temperature, humidity and composition, including the temperature, flow rate, conductivity, composition and other parameters of the coolant.

Specifically, the electric energy output by the electrochemical reaction of the stack is related to the operating parameters. Under the specific operating conditions of the stack, the above working parameters are set to sufficient energy supply to maintain the output voltage and current of the stack in compliance with a characteristic curve. Regularity, that is, it will not happen that the output voltage and current of the stack cannot meet the operating rules of the characteristic curve because the corresponding setting amount of a certain working condition parameter is insufficient. Therefore, when the stack is operating under sufficient conditions corresponding to the preset working conditions, if the water content demand of the stack changes, the characteristic curve will be moved up or down to achieve different consumption of reactants by the stack, thereby changing the metering ratio. , to achieve changes in the water content of the stack. Specifically, an upward/downward shift characteristic curve is generated in real time. By moving the characteristic curve upward, the fuel cell stack output voltage is increased, thereby reducing the fuel cell stack output current, reducing water generation, reducing the stack water content, or changing the characteristic curve Move downward to reduce the fuel cell stack output voltage, thereby increasing the fuel cell stack output current, increasing water generation, and increasing the stack water content.

In some embodiments, when the operating conditions of the cathode gas supply subsystem, anode gas supply subsystem and cooling management subsystem remain unchanged, when the characteristic curve is moved up or down, the power control subsystem real-time The stack output voltage and current are monitored and maintained on the characteristic curve.

Specifically, when the operating conditions of the cathode gas supply subsystem, anode gas supply subsystem and cooling management subsystem do not need to be changed, when the characteristic curve is moved up or down, the power supply is monitored in real time through the power control subsystem. The voltage and current output by the stack are maintained on a characteristic curve generated in real time. The characteristic curve can be an upward-moving characteristic curve or a downward-moving characteristic curve. Moreover, the relationship between the voltage and current changes on this characteristic curve also satisfies the upper and lower reference characteristic curves corresponding to the highest and lowest voltage operating ranges.

As shown in Figure 2, when the operating conditions of the cathode gas supply subsystem, anode gas supply subsystem and cooling management subsystem do not need to be changed, if they have the same gas supply volume and gas supply composition, and the working conditions will not As a result, the voltage and current output of the stack cannot be realized. When the characteristic curve is moved up or down, the voltage and current points output by the stack move along the iso-conditional curve shown in Figure 2 and remain on an upward-moving characteristic curve or a downward-moving characteristic curve generated in real time, that is, at The intersection point of the iso-conditional curve and the real-time generated characteristic curve. For example, if the intersection point of the upward-moving characteristic curve and the iso-conditional curve moves relatively to the upper left, the voltage will increase relatively, the current will decrease relatively, and the amount of water generated will decrease; under the same gas supply volume and gas supply composition, the reactor reaction metering ratio will become larger. Not only does it reduce the amount of water generated, but because the air intake does not increase, the exhaust volume increases, thereby increasing the drainage volume and reducing the relative humidity of the stack. In addition, when the intersection point of the downshift characteristic curve and the iso-conditional curve moves to the lower right, the voltage is relatively reduced, the current is relatively increased, and the amount of water generated increases; under the same gas supply volume and gas supply composition, the reactor reaction metering ratio becomes smaller, not only Increasing the amount of water generated, since the air intake volume does not increase, the exhaust volume decreases, thereby reducing the drainage volume and achieving an increase in the relative humidity of the stack. For example, in the above-mentioned stack water content operation adjustment process, there is no need to change the operating condition parameters of the fuel cell stack during operation, and the stack water content can be changed only by changing the setting of the power control subsystem.

Even if the stack operates under different operating conditions such as air supply volume, as long as the stack is in a clear and sufficient air supply environment and the characteristic curve is moved up or down, the voltage will be relatively increased and the output current of the stack will be reduced. , the generated water is reduced, thereby reducing the water content of the stack. Relatively lowering the voltage, the output current of the stack increases, and more water is generated, thereby increasing the water content of the stack.

As shown in the example of Figure 4, an embodiment of this specification provides a device 40 for controlling the water content of a fuel cell stack in a fuel cell system, which includes:

The acquisition module 41 determines at least one characteristic curve; the characteristic curve represents the relationship between the output voltage of the fuel cell stack and the output current as the working conditions change and under the control of the power control subsystem; wherein, the power control The subsystem monitors the output voltage and current of the stack in real time, and automatically adjusts the output power of the stack to keep the voltage and current output by the stack on the characteristic curve;

The operation module 42 is used to move the characteristic curve upward or downward according to the changing requirements of the stack water content in the fuel cell system; by moving the characteristic curve upward, the fuel cell stack output voltage is increased, thereby reducing the fuel cell voltage. The stack output current can reduce the generated water and reduce the stack water content, or move the characteristic curve downward to reduce the fuel cell stack output voltage, thereby increasing the fuel cell stack output current, increasing the generated water, and increasing the stack water content;

Among them, the upward-moving characteristic curve has a fuel cell stack output voltage higher than the current characteristic curve; the downward-moving characteristic curve has a lower fuel cell stack output voltage than the current characteristic curve.

The device of the embodiment shown in Figure 4 can be used to perform the steps in the method embodiment shown in Figure 3. The implementation principles and technical effects are similar and will not be described again here.

The control system 50 for the water content of the fuel cell stack in the fuel cell system as shown in the example of Figure 5 may include: a processor 51, a memory 52, and a computer program; where the memory is used to store the computer program, and the memory may also be a flash memory. (flash). The computer program is, for example, an application program, functional module, etc. that implements the above method. A processor, configured to execute the computer program stored in the memory to implement each step performed by the device in the above method. For details, please refer to the relevant descriptions in the previous method embodiments.

Optionally, the memory can be either independent or integrated with the processor.

When the memory is a device independent of the processor, the device may also include:

Bus 53 is used to connect the memory and the processor.

The present invention also provides a readable storage medium. A computer program is stored in the readable storage medium. When the computer program is executed by a processor, the computer program is used to implement the methods provided by the above-mentioned various embodiments.

The readable storage medium may be a computer storage medium or a communication medium. Communication media includes any medium that facilitates transfer of a computer program from one place to another. Computer storage media can be any available media that can be accessed by a general purpose or special purpose computer. For example, a readable storage medium is coupled to a processor such that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium may also be an integral part of the processor. The processor and the readable storage medium may be located in Application Specific Integrated Circuits (ASIC for short). Additionally, the ASIC can be located in the user equipment. Of course, the processor and the readable storage medium may also exist as discrete components in the communication device. Readable storage media can be read-only memory (ROM), random-access memory (RAM), CD-ROM, tapes, floppy disks, optical data storage devices, etc.

It should be noted that the terms “first”, “second”, “third”, “fourth”, etc. (if present) in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects. , and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the invention described herein are capable of being practiced in sequences other than those illustrated or described herein.

The same and similar parts between the various embodiments in this specification can be referred to each other, and each embodiment focuses on its differences from other embodiments. In particular, for the product embodiments described later, since they correspond to the methods, the description is relatively simple. For relevant details, please refer to the partial description of the system embodiments.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. All are covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims (10)

1. A method of controlling a water content of a fuel cell stack in a fuel cell system, the method comprising:

determining at least one characteristic; the characteristic curve represents the change relation of the output voltage of the fuel cell stack along with the output current under the control of the power control subsystem along with the change of working conditions; the electric power control subsystem monitors the output voltage and current of the electric pile in real time, and automatically adjusts the output electric energy of the electric pile, so that the output voltage and current of the electric pile are kept on the characteristic curve;

performing an up-shift or down-shift operation on the characteristic curve according to the stack water content change requirement in the fuel cell system; the characteristic curve is moved upwards to improve the output voltage of the fuel cell stack, so that the output current of the fuel cell stack is reduced, the generated water is reduced, the water content of the stack is reduced, or the characteristic curve is moved downwards to reduce the output voltage of the fuel cell stack, so that the output current of the fuel cell stack is improved, the generated water is increased, and the water content of the stack is improved;

wherein the upward-shifting characteristic curve has a higher fuel cell stack output voltage than the current characteristic curve; the downshifting characteristic has a lower fuel cell stack output voltage than the current characteristic.

2. The method for controlling the water content of a fuel cell stack in a fuel cell system according to claim 1, wherein the shifting up or down of the characteristic curve according to the stack water content variation demand in the fuel cell system comprises:

if the fuel cell system is set to reduce the water content of the electric pile, generating an upward movement characteristic curve in real time according to the reference characteristic curve, the upward movement reference characteristic curve and the upward movement degree;

alternatively, if the fuel cell system is set to increase the stack water content, a downward movement characteristic is generated in real time based on the reference characteristic, the downward movement reference characteristic, and the degree of downward movement.

3. The method of controlling the water content of a fuel cell stack in a fuel cell system according to claim 2, wherein an upward-shifting reference characteristic and a downward-shifting reference characteristic are determined by operating the fuel cell system in respective preset operating conditions; the upward movement reference characteristic curve and the downward movement reference characteristic curve limit the range of the change relation of the stack output voltage corresponding to each characteristic curve along with the stack output current, wherein the upward movement reference characteristic curve has the highest fuel cell stack output voltage, and the downward movement reference characteristic curve has the lowest fuel cell stack output voltage.

4. A method of controlling the water content of a fuel cell stack in a fuel cell system according to claim 3, wherein the preset operating conditions corresponding to the output voltage and current of the stack include operating parameters of the stack, wherein the operating parameters include the air supply pressure, flow rate, temperature, humidity and composition corresponding to the anode and cathode of the fuel cell, respectively, and further include the temperature, flow rate, conductivity and composition of the coolant.

5. A method of controlling the water content of a fuel cell stack in a fuel cell system according to claim 3, wherein the characteristic curve is shifted up or down in real time without changing the operating conditions of the cathode gas supply subsystem, the anode gas supply subsystem and the cooling management subsystem, and the power control subsystem monitors the voltage and current outputted from the stack in real time and maintains the voltage and current on the characteristic curve.

6. A control apparatus for a water content of a fuel cell stack in a fuel cell system, characterized in that the control apparatus for a water content of a fuel cell stack in a fuel cell system comprises:

the acquisition module is used for determining at least one characteristic curve; the characteristic curve represents the change relation of the output voltage of the fuel cell stack along with the output current under the control of the power control subsystem along with the change of working conditions; the electric power control subsystem monitors the output voltage and current of the electric pile in real time, and automatically adjusts the output electric energy of the electric pile, so that the output voltage and current of the electric pile are kept on the characteristic curve;

the operation module is used for performing upward movement or downward movement operation on the characteristic curve according to the change requirement of the water content of the electric pile in the fuel cell system; the characteristic curve is moved upwards to improve the output voltage of the fuel cell stack, so that the output current of the fuel cell stack is reduced, the generated water is reduced, the water content of the stack is reduced, or the characteristic curve is moved downwards to reduce the output voltage of the fuel cell stack, so that the output current of the fuel cell stack is improved, the generated water is increased, and the water content of the stack is improved;

wherein the upward-shifting characteristic curve has a higher fuel cell stack output voltage than the current characteristic curve; the downshifting characteristic has a lower fuel cell stack output voltage than the current characteristic.

7. The control apparatus for fuel cell stack moisture content in a fuel cell system according to claim 6, wherein the shifting up or down of the characteristic curve according to the stack moisture content change demand in the fuel cell system comprises:

if the fuel cell system is set to reduce the water content of the electric pile, generating an upward movement characteristic curve in real time according to the reference characteristic curve, the upward movement reference characteristic curve and the upward movement degree;

alternatively, if the fuel cell system is set to increase the stack water content, a downward movement characteristic is generated in real time based on the reference characteristic, the downward movement reference characteristic, and the degree of downward movement.

8. The control apparatus for fuel cell stack water content in a fuel cell system according to claim 7, wherein an upward-shifting reference characteristic and a downward-shifting reference characteristic are determined by operating the fuel cell system in respective preset operating conditions; the upward movement reference characteristic curve and the downward movement reference characteristic curve limit the range of the change relation of the stack output voltage corresponding to each characteristic curve along with the stack output current, wherein the upward movement reference characteristic curve has the highest fuel cell stack output voltage, and the downward movement reference characteristic curve has the lowest fuel cell stack output voltage.

9. A control system for the water content of a fuel cell stack in a fuel cell system, comprising: a memory, a processor, and a computer program stored in the memory, the processor running the computer program to perform the method of controlling the water content of a fuel cell stack in a fuel cell system according to any one of claims 1 to 5.

10. A readable storage medium, characterized in that the readable storage medium has stored therein a computer program which, when executed by a processor, is adapted to carry out the method of controlling the water content of a fuel cell stack in a fuel cell system according to any one of claims 1-5.