CN117276585A

CN117276585A - Fuel cell system, humidification system, method of operating a fuel cell system, and computer program product

Info

Publication number: CN117276585A
Application number: CN202210669877.4A
Authority: CN
Inventors: 董仁; S·雅诺什
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2023-12-22

Abstract

Disclosed is a humidification system (17) for a fuel cell system (1) including an intake passage (13) for supplying air to a cathode inlet (113) of a stack (11) and an air compressor (14) provided on the intake passage for pressurizing the air, the humidification system being provided downstream of the air compressor and including: a humidification channel (171) with an adjustable first flow capacity and a bypass channel (172) with an adjustable second flow capacity arranged in parallel; a humidifier provided in the humidification passage and humidifying air; a humidification controller (16) configured to be capable of controlling the first and second flow capacities based at least on the humidity control target in a manner that ensures that at least one of the first and second flow capacities is non-zero. A fuel cell system, a method of operating the same, and a corresponding computer program product are also disclosed. The problem that the error calibration causes a stop is avoided.

Description

Fuel cell system, humidification system, method of operating a fuel cell system, and computer program product

Technical Field

The present invention relates to the field of fuel cells, in particular fuel cell systems for vehicles, in particular to a humidification system for a fuel cell system, a corresponding method of operating a fuel cell system and a corresponding computer program product.

Background

A fuel cell is an electrochemical power generation device that directly converts chemical energy into electric energy, and is a widely paid attention and development as a next-generation energy source because it consumes no fossil fuel and has almost zero emission. Among the various types of fuel cells, proton exchange membrane fuel cells are a widely used type that has important advantages of low operating temperature, rapid start-up, and the like, and thus the proton exchange membrane fuel cells are particularly suitable for electric vehicles.

In proton exchange membrane fuel cells, hydrogen is typically used as the fuel, air or pure oxygen as the oxidant, with the polymer membrane as the electrolyte, conducting protons (hydrogen cations) generated in the anode region to the cathode region. For proton exchange membrane type fuel cells, maintaining the humidity of the normal proton exchange membrane is very critical, which directly affects the optimal performance of the proton exchange membrane, since the ionic conductivity depends in particular on the hydration level, and a greater hydration capacity leads to a higher conductivity and thus to a more efficient cell. However, too high a hydration level may also lead to the formation of a liquid water layer, which may cause performance and reliability problems, such as blocking of porous paths by the liquid water layer, and thus voltage loss at high current densities, voltage instability, unreliable start-up at zero temperature conditions, etc. Therefore, it is very important to control the humidity in the fuel cell.

Currently, humidifiers, such as self-humidifiers, water tanks, jet humidifiers, and the like, are commonly used to increase the humidity of air supplied to the fuel cell stack. Specifically, air is pressurized by an air compressor, one path of air after pressurization passes through a humidifier to obtain air with increased humidity, and the path of air is supplied to the fuel cell stack through a humidifying valve. At the same time, the other air is mixed with the humidified air by bypassing the humidifier through the bypass valve to adjust the air of the desired humidity as needed. In operation, the humidifying valve is always fully opened, and the humidity of the mixed air is controlled by continuously controlling the bypass valve.

However, if the cathode humidity of the fuel cell stack is still high when the bypass valve is fully open, there is no measure that can be taken to reduce the humidity. For this reason, it is proposed to control humidity by controlling the opening degrees of both the humidification valve and the bypass valve. However, if the fuel cell system is misclassified, the system may determine that both valves need to be closed at the same time in some cases, at which time the fuel cell system may have to be shut down, which is very disadvantageous.

For this reason, there is a continuing need for improvement.

Disclosure of Invention

It is an object of the present invention to provide an improved humidification system for a fuel cell system, a corresponding method of operating a fuel cell system and a corresponding computer program product, which overcome at least one of the above mentioned disadvantages and/or any other disadvantages which may not be mentioned herein.

According to a first aspect of the present invention, there is provided a humidification system for a fuel cell system, wherein the fuel cell system includes an intake passage for supplying air to a cathode inlet of a stack of the fuel cell system and an air compressor provided on the intake passage for pressurizing the air, the humidification system being provided downstream of the air compressor and including: a humidification channel and a bypass channel disposed in parallel relationship to each other, wherein the humidification channel has an adjustable first flow capacity and the bypass channel has an adjustable second flow capacity; a humidifier provided in the humidification passage and humidifying air; and a humidification controller configured to be capable of controlling the first and second through-flow capacities based at least on the humidity control target in a manner that ensures that at least one of the first and second through-flow capacities is non-zero.

According to a second aspect of the present invention, there is provided a fuel cell system, wherein the fuel cell system includes the humidification system.

According to a third aspect of the present invention, there is provided a method for operating the fuel cell system, the method comprising at least: determining a humidity control target for the fuel cell system; and controlling the first and second through-flow capacities based at least on the humidity control target in a manner that ensures that at least one of the first and second through-flow capacities is non-zero.

According to an alternative embodiment of the present invention, a basic configuration state of the first and second through-flow capacities is determined by judging an area in which the humidity control target is located and the first and/or second through-flow capacities are adjusted based on the basic configuration state.

According to a fourth aspect of the present invention, there is provided a computer program product, in particular a computer readable program carrier, comprising or storing computer program instructions configured to implement the method when executed by a processor.

According to certain exemplary embodiments of the present invention, by calibrating the humidification valve and the bypass valve in common with respect to the humidity control target, situations in which both the humidification valve and the bypass valve need to be closed due to separate calibration may be avoided.

Drawings

The principles, features and advantages of the present invention may be better understood by describing the present invention in more detail with reference to the drawings. The drawings include:

fig. 1 schematically shows a schematic diagram of a part of a fuel cell system according to an exemplary embodiment of the present invention.

Fig. 2 shows a flowchart of a method for operating a fuel cell system according to an exemplary embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous technical effects to be solved by the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and a plurality of exemplary embodiments. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Fig. 1 schematically shows a schematic diagram of a part of a fuel cell system according to an exemplary embodiment of the present invention. Here, only parts closely related to the present invention are shown for the sake of clarity.

The fuel cell system 1 may be used in a vehicle to provide electrical power to drive a vehicle motor to provide power and/or to cause an on-board system to perform various functions. As shown in fig. 1, the fuel cell system 1 is, for example, a Proton Exchange Membrane Fuel Cell (PEMFC) system and includes a stack 11. The stack 11 includes an anode 111 and a cathode 112. During operation of the fuel cell system 1, hydrogen and air need to be supplied to the anode 111 and the cathode 112 of the stack 11, respectively. The hydrogen molecules entering the anode 111 are adsorbed by the catalyst and ionized into hydrogen ions and electrons, the hydrogen ions are transferred to the cathode 112 via a proton exchange membrane (not shown in particular) in the stack 11, and the electrons flow to the cathode 112 through an external circuit (not shown) to form an electric current. Air enters the cathode 112 from the cathode inlet 113, oxygen in the air combines with hydrogen ions and electrons at the cathode 112 into water molecules, and is discharged from the cathode outlet 114 to the exhaust passage 12 together with other residual gas components in the air.

In order to supply air to the stack 11, the fuel cell system 1 includes an intake passage 13 configured to supply air to a cathode inlet 113 of the stack 11, an air compressor 14 provided on the intake passage 13 and configured to pressurize the air, and an intercooler 15 provided on the intake passage 13 downstream of the air compressor 14 and configured to cool the pressurized air. The air compressor 14 may be any type of machine for compressing a gas that is operable to draw air into the intake passage 13 from the environment external to the fuel cell system 1. The temperature, pressure and flow rate of the air discharged from the air compressor 14 are all increased due to the pressurizing action of the air compressor 14. The operation of the air compressor 14 (e.g., power of the air compressor 14, spindle speed, etc.) may be controlled, for example, by a fuel cell control unit (FCU) (not shown) of the fuel cell system 1 based on the operating conditions of the fuel cell system 1 (e.g., power or current of the fuel cell system 1, etc.). The intercooler 15 may be any suitable cooling device capable of cooling a gas (e.g., an air cooling device, a liquid cooling device, or a combination thereof), and the intercooler 15, when in operation, cools the pressurized air as it passes therethrough. The temperature of the pressurized air is reduced as a result of being cooled by the intercooler 15.

It will be appreciated by those skilled in the art that although intercooler 15 is shown herein, in some cases, for example, intercooler 15 may in principle be omitted if the temperature of the pressurized air is not significantly increased or the temperature after the increase is allowed or downstream components may cool the air such that the temperature of the air entering cathode inlet 113 is appropriate.

As shown in fig. 1, the fuel cell system 1 may further include a humidification controller 16 to control the humidification operation of the fuel cell system 1. The humidification controller 16 may communicate with the fuel cell control unit to receive humidification adjustment requests, for example, from the fuel cell control unit.

In order to maintain the water content in the stack 11 at a suitable level, the fuel cell system 1 further comprises a humidification system 17. A humidifying system 17 is provided on the intake passage 13 downstream of the intercooler 15. Humidification system 17 includes a humidification passage 171 and a bypass passage 172 configured to be connected between intercooler 15 and cathode inlet 113, respectively. The humidification passage 171 is provided with a humidification valve 173 capable of adjusting the flow capacity of the humidification passage 171, which is referred to herein as a first flow capacity, and the bypass passage 172 is provided with a bypass valve 174 capable of adjusting the flow capacity of the bypass passage 172, which is referred to herein as a second flow capacity. As schematically shown in fig. 1, the humidification valve 173 and the bypass valve 174 may be controlled by the humidification controller 16, i.e., the first and second throughflow capacities may be automatically, in particular electronically, adjusted by the humidification controller 16. "automatically" is relative to manually.

By "flow capacity" is meant herein the capacity of a channel to allow fluid to pass through, which is generally characterized by the effective cross-sectional area of the channel for the flow of fluid. In other words, the first and second through-flow capacities may be controlled by controlling the opening degrees of the humidification valve 173 and the bypass valve 174, respectively.

Humidification system 17 also includes a humidifier 175 disposed on humidification channel 171 to humidify the air. Humidifier 175 may be any suitable humidifying device that humidifies air as it passes therethrough, such as a liquid water jet humidifier, a wet film humidifier, a bubbling humidifier, a permeable film humidifier, or the like. The humidifier 175 may also be a self-humidifier configured to humidify the air to be supplied to the cathode inlet 113 with the off-gas discharged from the cathode outlet 114 because the off-gas discharged from the cathode outlet 114 has a higher water content than the air to be supplied to the cathode inlet 113, in which case the exhaust passage 12 may pass through the humidifier 175. The invention is not limited in this regard.

As one example, the humidification controller 16 may be configured to respond to a humidification adjustment request from the fuel cell system 1 based on the relative humidity RH of the air at the outlet of the intercooler 15 _ICDs The first and second throughflow capacities are adjusted to control the relative humidity of the air entering the cathode inlet 113. Specifically, when the operating condition of the fuel cell system 1 (e.g., the power or current of the fuel cell system) changes, the fuel cell control unit sends a humidification adjustment request to the humidification controller 16, for example, indicating the desired relative air humidity RH entering the cathode inlet 113 _CIP . For example, the desired relative humidity RH _CIP The calibration or calculation may be performed in advance based on the operation conditions of the fuel cell system 1, such as the power or current, the power of the compressor, and the like. The humidification controller 16 responds to the humidification adjustment request based on the relative humidity RH of the air at the outlet of the intercooler 15 _ICDs The first and second throughflow capacities are adjusted to adjust the relative proportion of the portion of the air that is humidified by the humidification passage 171 as it passes through the humidification system 17 to the portion that is not humidified by the bypass passage 172 directly. In this way, the degree to which air is humidified as it passes through the humidification system 17 can be accurately controlled to control the relative humidity of the air entering the cathode inlet 113. By cooperative control of the humidification valve 173 and the bypass valve 174, the humidification system 17 can more precisely control the relative humidity of the air entering the cathode inlet 113 relative to the humidification system of the related art to precisely maintain the stack moisture content in the fuel cell system 1 at a desired level, thereby ensuring reliable and efficient operation of the fuel cell system 1.

Relative humidity RH of air at the outlet of intercooler 15 _ICDs Can be determined in a number of ways, for example by direct measurement by a sensor of the corresponding typeOr indirectly through measurement data of other sensors. The invention is not limited in this regard.

The humidification controller 16 is configured to, for example, adjust the desired relative air humidity RH into the cathode inlet 113 indicated by the humidification adjustment request _CIP Relative humidity RH with the determined air at the outlet of the charge air cooler 15 _ICDs Compare and based on the desired relative humidity RH of the air _CIP Relative humidity RH with the determined air at the outlet of the charge air cooler 15 _ICDs Difference RH _CIP -RH _ICDs To determine adjustment target values for the first and second throughflow capacities. The adjusted target values of the first and second throughflow capacities may be correlated, for example, by calibration, with the aforementioned difference and/or fuel cell operating conditions, such as operating parameters of the air compressor 14, for example, by MAP MAPs. In one exemplary embodiment, the adjustment target values for the valve opening of the humidification valve 173 and the bypass valve 174 described above may be correlated, for example, by calibration, with the aforementioned difference and/or the power of the air compressor 14 (since the power of the air compressor 14 determines the flow of air in the intake passage 13). The humidification controller 16 is further configured to control the humidity of the air at a desired relative humidity RH _CIP Relative humidity RH with the determined air at the outlet of the charge air cooler 15 _ICDs When the difference becomes large (for example, the relative humidity of the air taken into the cathode inlet 113 needs to be increased, the air taken into the air intake passage 13 through the air compressor 14 becomes drier than before) according to the operating state of the stack 11, the first through-flow capacity is increased and/or the second through-flow capacity is decreased, and when the relative humidity RH of the air is desired _CIP Relative humidity RH with the determined air at the outlet of the charge air cooler 15 _ICDs When the difference becomes small (for example, the relative humidity of the air taken into the cathode inlet 113 needs to be reduced, and the air taken into the intake passage 13 through the air compressor 14 becomes more humid than before) depending on the operating state of the stack 11, the first through-flow capacity is reduced and/or the second through-flow capacity is increased. In this way, the relative humidity RH of the air can be expected _CIP And the determined relative humidity RH of the air at the outlet of the intercooler 15 _ICDs Is faster when at least one of them is changedAnd more precisely adjusts the ratio of the portion of the air that is humidified by the humidifying passage 171 to the portion that is not humidified by the bypass passage 172 when passing through the humidifying system 17. In this way, the relative humidity of the air entering the cathode inlet 113 can be controlled more quickly and more accurately, thereby ensuring reliable and efficient operation of the fuel cell system 1.

In the above-described embodiment, the influence of the temperature change of the air from the outlet of the intercooler 15 to the cathode inlet 113 on the relative humidity of the air is not considered, but it is assumed that the temperature of the air from the outlet of the intercooler 15 to the cathode inlet 113 does not change. It is known that under certain other conditions, an increase in the temperature of the air will cause its relative humidity to decrease and a decrease in the temperature will cause its relative humidity to increase.

In order to more precisely control the relative humidity of the air entering the cathode inlet 113, the humidification controller 16 is further configured to modify the adjustment of the first and second throughflow capacities based on the temperature change of the air from the outlet of the intercooler 15 to the cathode inlet 113. In this way, the influence of the temperature change of the air from the outlet of the intercooler 15 to the cathode inlet 113 on the relative humidity of the air can be corrected, thereby enabling more accurate control of the relative humidity of the air entering the cathode inlet 113. This makes it possible to more accurately maintain the stack water content in the fuel cell system 1 at a desired level, thereby ensuring reliable and efficient operation of the fuel cell system 1.

It will also be appreciated by those skilled in the art that in other embodiments, the air temperature at the cathode inlet 113 may be pre-calibrated based on the operating conditions of the fuel cell system (including the humidification system 17) to correlate to the target adjustment values for the first and second throughflow capacities, rather than taking into account the specific temperature at the outlet of the intercooler 15.

As is apparent from the above description, the relative humidity of the air at the cathode inlet 113 of the fuel cell system 1 is associated with various factors as a subject of adjustment, which is complicated. However, a relationship may be established between various factors, such as by calibration, to determine the adjusted target values of the first and second throughflow capacities as desired. In this regard, only a few exemplary association factors are given above, but it is apparent that the present invention is not limited thereto, and the association factors may be changed or adjusted according to actual system conditions or operating scenarios.

Regardless of the complexity of the system, the correlation factor is, in effect, the relationship between the humidity control target at the cathode inlet 113 and the adjustment targets for the first and second throughflow capacities, as determined by the system based on the operating conditions. In other words, it is essentially a matter of how to adjust the first and second through-flow capacities according to the humidity control target to facilitate the implementation of the humidity control target.

As one example, the humidity control target may be an indication of a desired relative humidity RH of the air entering the cathode inlet 113 _CIP Which may be sent by the fuel cell control unit to the humidification controller 16.

Based on the above description, it will be appreciated by those skilled in the art that the desired relative humidity RH of air given by the fuel cell control unit is due to the influence of the air taken in from the intake passage 13 through the air compressor 14, the intercooler 15, the humidifier 175, and the corresponding piping, etc _CIP May be determined based on the operating conditions of the fuel cell system 1 (e.g., power or current of the fuel cell system) without consideration of these influencing factors, or may be a humidity control target given by comprehensively considering these influencing factors and/or other possible influencing factors. Thus, the "humidity control target" as referred to herein refers to a control target to be achieved directly or indirectly by adjusting the first and/or second throughflow capacity, i.e., may be a desired relative air humidity RH at the cathode inlet 113 _CIP Relative humidity RH to the desired air may also be _CIP Other humidity control objectives are relevant.

That is, in practice, the specific relationship between the humidity control target and the first and second throughflow capacities is not of great concern to the present invention, and the relationship therebetween may be determined in various ways, particularly in a calibrated manner. Such a relationship may be referred to as a predetermined relationship, in particular a predetermined calibration relationship, for example in the form of a MAP.

However, if it is determined that both the humidification valve 173 and the bypass valve 174 need to be closed, for example, according to a predetermined relationship during the operation of the fuel cell system 1, this will cause no air to enter the stack 11, and the fuel cell system 1 has to be stopped.

For this reason, according to the present invention, it is necessary to avoid the situation where the humidification valve 173 and the bypass valve 174 are closed at the same time during humidity adjustment.

According to an exemplary embodiment of the present invention, the situation that the first through-flow capability and the second through-flow capability are simultaneously zero may be avoided, for example, by properly calibrating the relationship between the humidity control target and the first through-flow capability and the second through-flow capability.

In the following, one possible embodiment will be described exemplarily and cooperatively for explaining the basic principle of the present invention.

Assuming that the humidification passage 171 and the bypass passage 172 have the same maximum flow capacity, the air humidity at the cathode inlet 113 is maximum when the bypass valve 174 is fully closed and the humidification valve 173 is fully opened, under other conditions, the corresponding humidity control target T is t=tmax, where Tmax may be exemplarily represented as 200% for easier understanding for more specific description (it is noted that this is not the true actual relative humidity, but the humidity of the air discharged from the humidifier 175 is taken as a reference humidity reference, and represented as 200%); if both bypass valve 174 and humidification valve 173 are fully open (the humidified air will be diluted by a factor of two, ignoring the relative humidity of the ambient air itself), the corresponding humidity control target t=t1, which may be represented exemplarily as t1=100% with respect to the above-mentioned reference humidity reference; if the humidification valve 173 is fully opened, the air humidity at the cathode inlet 113 will decrease as the bypass valve 174 is gradually opened to the maximum flow, and the corresponding humidity control target T is in the range of T1 to Tmax; if bypass valve 174 is fully open and humidification valve 173 is fully closed, then only non-humidified gas enters cathode inlet 113, where the air humidity at cathode inlet 113 is minimal, and the corresponding humidity control target T is t=tmin, which may be expressed as 0% (note that this is not true relative humidity either); if the bypass valve 174 is fully opened, as the humidification valve 173 is gradually opened to the maximum flow, the air humidity at the cathode inlet 113 will rise accordingly, with the corresponding humidity control target T being between Tmin-T1.

Thus, by controlling the humidification valve 173 and the bypass valve 174 in cooperation, a range of relative humidity variation corresponding to 0% -200% can be obtained at the cathode inlet 113, without also giving a case where the humidification valve 173 and the bypass valve 174 are completely closed at the same time.

Having described above that the bypass valve 174 and the humidification valve 173 are in different states to achieve the corresponding humidity control ranges, according to an exemplary embodiment of the present invention, the basic on-off states of the humidification valve 173 and the bypass valve 174, particularly, which valve can be kept fully open, may be determined according to the interval in which the humidity control target is located, and then adjusted accordingly. For example, when the humidity control target T is determined to be in the interval of T1 to Tmax, it may be determined that the opening degree of the bypass valve 174 may be controlled in a state where the humidification valve 173 is fully opened to achieve the humidity control target. This control makes it no longer possible for the humidification valve 173 and the bypass valve 174 to be closed simultaneously. The control targets of other intervals can be realized in a corresponding mode, and the detailed description is omitted.

Of course, it will be appreciated by those skilled in the art that the adjustment need not be made on the basis of having at least one valve fully open. Regardless of the adjustment, it is sufficient to ensure that the bypass valve 174 and the humidification valve 173 are not completely closed at the same time. In particular, for the air entering the cathode inlet 113, it may be necessary to control the flow rate thereof in addition to the humidity thereof, and for this reason, "fully open" given above is only one example, and it may be practically required to be in an appropriate open state as required. For example, the relative relationship between the first and second throughflow capacities may be determined based on the humidity control target, and then the actual sizes of the first and second throughflow capacities may be determined based on the flow adjustment target, but ensuring that at least one of the first and second throughflow capacities is non-zero.

To this end, the invention relates to a method for controlling a fuel cell system 1. Fig. 2 shows a flow chart of an exemplary embodiment of the method. As shown in fig. 2, the method comprises the steps of: s1) determining a humidity control target T of the fuel cell system 1; s2) adjusting the first through-flow capability and the second through-flow capability according to a predetermined relationship based on the humidity control target T, wherein the predetermined relationship is at least used for characterizing the relationship between the first through-flow capability, the second through-flow capability and the humidity control target such that for any humidity control target, the first through-flow capability and the second through-flow capability cannot be zero at the same time, i.e. at least one of the first through-flow capability and the second through-flow capability is non-zero. This may be ensured by co-calibrating the first and second throughflow capacities.

The invention also relates to a computer program product, in particular a computer readable program carrier, having stored thereon program instructions which, when executed by a processor, are capable of performing the above-mentioned method.

Although specific embodiments of the invention have been described in detail herein, they are presented for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications can be made without departing from the spirit and scope of the invention.

List of reference numerals

1. Fuel cell system

11. Electric pile

111. Anode

112. Cathode electrode

113. Cathode inlet

114. Cathode outlet

12. Exhaust passage

13. Air inlet channel

14. Air compressor

15. Intercooler

16. Humidification controller

17. Humidification system

171. Humidification channel

172. Bypass passage

173. Humidification valve

174. Bypass valve

175. Humidifier

Claims

1. A humidification system (17) for a fuel cell system (1), wherein the fuel cell system (1) includes an intake passage (13) for supplying air to a cathode inlet (113) of a stack (11) of the fuel cell system (1) and an air compressor (14) provided on the intake passage (13) for pressurizing the air, the humidification system (17) being provided downstream of the air compressor (14) and comprising:

a humidification channel (171) and a bypass channel (172) arranged in parallel relationship to each other, wherein the humidification channel (171) has an adjustable first flow capacity and the bypass channel (172) has an adjustable second flow capacity;

a humidifier (175) provided in the humidification passage (171) and humidifying the air; and

a humidification controller (16), the humidification controller (16) configured to be capable of controlling the first and second through-flow capacities based at least on the humidity control objective in a manner that ensures that at least one of the first and second through-flow capacities is non-zero.

2. The humidification system (17) of claim 1, wherein,

the fuel cell system (1) further comprises an intercooler (15) located downstream of the air compressor (14) and upstream of the humidification system (17); and/or

A humidifying valve (173) capable of adjusting the first through-flow capacity is arranged on the humidifying channel (171); and/or

The bypass passage (172) is provided with a bypass valve (174) capable of adjusting the second flow capacity.

3. The humidification system (17) of claim 1 or 2, wherein,

the humidification controller (16) is configured to control the first throughput capability and the second throughput capability based on at least a predetermined relationship for characterizing a relationship between the first throughput capability, the second throughput capability, and the humidity control target; and/or

The humidity control target is based on a desired relative humidity of air entering the cathode inlet (113) of the stack (11).

4. A humidification system (17) according to claim 3, wherein,

the predetermined relationship is determined by co-calibrating the first and second throughflow capacities relative to the humidity control target; and/or

The humidity control target is a desired relative humidity of air entering the cathode inlet (113) of the stack (11).

5. A fuel cell system (1), wherein the fuel cell system (1) comprises a humidification system (17) according to any one of claims 1-4.

6. A method for operating a fuel cell system (1) according to claim 5, the method comprising:

determining a humidity control target of the fuel cell system (1); and

the first and second through-flow capacities are controlled in a manner that ensures that at least one of the first and second through-flow capacities is non-zero based at least on the humidity control target.

7. The method of claim 6, wherein,

the first through-flow capability and the second through-flow capability are controlled based on at least a predetermined relationship characterizing a relationship between the first through-flow capability, the second through-flow capability and the humidity control target.

8. The method according to claim 6 or 7, wherein,

and determining basic configuration states of the first through-flow capacity and the second through-flow capacity by judging the area where the humidity control target is located, and adjusting the first through-flow capacity and/or the second through-flow capacity based on the basic configuration states.

9. The method of claim 8, wherein,

the region includes at least a first section and a second section that do not overlap each other, wherein:

maintaining the second throughflow capacity non-zero, in particular maximum, while the humidity control target is in the first interval, the humidity control target being achieved by adjusting the first throughflow capacity;

when the humidity control target is in the second interval, the first throughflow capacity is kept non-zero, in particular kept maximum, while the humidity control target is achieved by adjusting the second throughflow capacity.

10. The method of claim 9, wherein,

the first interval is defined by a first endpoint and a second endpoint without including the first endpoint and the second endpoint, and the second interval is defined by the second endpoint and a third endpoint without including the second endpoint and the third endpoint, wherein:

maintaining the second through-flow capacity non-zero, in particular maximum, while the humidity control target is at the first end point, while the first through-flow capacity is zero;

maintaining a non-zero, in particular a maximum, first and second throughflow capacity when the humidity control target is at the second end point;

when the humidity control target is at the third end point, the first through-flow capacity is kept non-zero, in particular at a maximum, and the second through-flow capacity is kept zero.

11. The method of claim 10, wherein,

the first end point is smaller than the second end point, and the second end point is smaller than the third end point.

12. A computer program product, in particular a computer readable program carrier, comprising or storing computer program instructions configured to implement the method of any one of claims 6-11 when executed by a processor.