CN116190716A - Hydrogen purging system, control method and fuel cell assembly system - Google Patents

Abstract

The invention belongs to the field of fuel cells, and particularly relates to a hydrogen purging system, a control method and a fuel cell assembly system. The hydrogen purging system comprises a fuel cell stack, a gas supply pipeline group, a return gas pipeline group and a purging pipeline group. The fuel cell stack comprises a stack hydrogen inlet and a stack hydrogen outlet; the gas supply pipeline group is connected to the hydrogen inlet of the electric pile and comprises a hydrogen source and a first control valve which are connected along the gas flow direction; the air return pipeline group is connected to the hydrogen outlet of the electric pile and comprises a first water-vapor separator and a hydrogen circulating pump which are connected along the air flow direction, and the outlet end of the hydrogen circulating pump is connected between the first control valve and the fuel cell electric pile; the purge line set is capable of storing hydrogen and is connected between the hydrogen source and an outlet end of the hydrogen circulation pump, and is configured to flow hydrogen toward the stack hydrogen inlet and recover stored hydrogen from the stack hydrogen outlet after the fuel cell stack is stopped. The hydrogen purging system can solve the problem that wet hydrogen stays in a galvanic pile to cause icing to damage the galvanic pile.

Description

Hydrogen purging system, control method and fuel cell assembly system

Technical Field

The invention belongs to the field of fuel cells, and particularly relates to a hydrogen purging system, a control method and a fuel cell assembly system.

Background

In the operation process of the fuel cell system, a large amount of water is generated, particularly the water on the hydrogen side is not easy to discharge, and after the ambient temperature is lower than zero, the water can freeze to damage the membrane electrode of the fuel cell, so that irreversible damage is caused.

The existing fuel cell system can circulate the hydrogen in the tail hydrogen row into the electric pile by adding a water-vapor separator and a hydrogen circulating pump so as to remove liquid water from the electric pile. According to the technical scheme, liquid water can only be discharged out of the electric pile through the water-vapor separator, and gaseous water in saturated wet hydrogen cannot be solved. In the shutdown process of the fuel cell, the temperature of the electric pile is high and cannot be quickly reduced, so that gaseous water cannot be discharged out of the electric pile, and the fuel cell can be liquefied into liquid water and frozen under the condition of low ambient temperature, thereby causing damage to the electric pile.

Disclosure of Invention

The invention provides a hydrogen purging system, a control method and a fuel cell assembly system, which are used for solving the technical problems in the prior art.

The first aspect of the invention provides a hydrogen purging system, which comprises a fuel cell stack, a gas supply pipeline group, a return gas pipeline group and a purging pipeline group. The fuel cell stack comprises a stack hydrogen inlet and a stack hydrogen outlet; the gas supply pipeline group is connected to the hydrogen inlet of the electric pile and comprises a hydrogen source and a first control valve which are connected along the gas flow direction; the air return pipeline group is connected to the hydrogen outlet of the electric pile and comprises a first water-vapor separator and a hydrogen circulating pump which are connected along the air flow direction, and the outlet end of the hydrogen circulating pump is connected between the first control valve and the fuel cell electric pile; the purge line set is capable of storing hydrogen and is connected between the hydrogen source and the outlet end of the hydrogen circulation pump, and is arranged to inject hydrogen toward the hydrogen inlet of the stack after the fuel cell stack stops operating and to recover the stored hydrogen from the hydrogen outlet of the stack.

Optionally, the purge line set includes a hydrogen chamber, a second control valve, a third control valve, and a fourth control valve; the hydrogen chamber comprises a first chamber inlet, a second chamber inlet and a chamber outlet, wherein the first chamber inlet is connected with a hydrogen source through a fourth control valve, the second chamber inlet is connected with the outlet end of the hydrogen circulating pump through a second control valve, and the chamber outlet is connected between the first control valve and the outlet end of the hydrogen circulating pump through a third control valve.

Optionally, the purge line set further comprises a second water-vapor separator connected between the second chamber inlet and the second control valve.

Optionally, the fourth control valve is a constant pressure relief valve.

Optionally, the hydrogen purging system further comprises a first sensor group and a second sensor group;

the first sensor group is connected with the gas supply pipeline group and is used for detecting the pressure and the humidity of hydrogen entering the fuel cell stack;

the second sensor group is connected to the hydrogen chamber for detecting intra-cavity pressure and intra-cavity humidity of the hydrogen chamber.

The second aspect of the present invention provides a control method, where the control method is applied to the above-mentioned hydrogen purging system, the hydrogen purging system further includes a control module, the control module is connected with the first control valve, the second control valve, the third control valve, the first water-vapor separator and the hydrogen circulating pump by signals, and the control module is configured to:

acquiring a system shutdown signal, and closing a first control valve;

under the condition that the first control valve is closed, controlling the hydrogen circulating pump to operate for a prolonged period;

under the condition that the hydrogen pressure is lower than the preset hydrogen pressure, the second control valve and the third control valve are controlled to be opened;

and under the condition that the hydrogen humidity is lower than the preset hydrogen humidity, the second control valve, the third control valve and the hydrogen circulating pump are controlled to be closed.

Optionally, controlling the hydrogen circulation pump to extend comprises:

and controlling the hydrogen circulating pump to operate in the limit operation state for a preset period of time.

Optionally, the hydrogen purging system further comprises a second water-vapor separator connected between the second chamber inlet and the second control valve, the second water-vapor separator being in signal connection with the control module;

the control module is further configured to:

acquiring intra-cavity pressure and intra-cavity humidity;

when the pressure in the cavity is larger than the first preset pressure in the cavity or the humidity in the cavity is larger than the first preset humidity in the cavity, the second water-vapor separator is controlled to be opened for air release;

and when the pressure in the cavity is smaller than the second preset pressure in the cavity and the humidity in the cavity is smaller than the second preset humidity in the cavity, controlling the second water-vapor separator to be closed, wherein the second preset pressure is lower than the first preset pressure in the cavity, and the second preset humidity in the cavity is lower than the first preset humidity in the cavity.

Optionally, the control module is further configured to:

acquiring a system starting signal;

determining target hydrogen pressure and target hydrogen humidity according to the system load;

and respectively controlling the first control valve and the hydrogen circulating pump according to the target hydrogen pressure and the target hydrogen humidity.

A third aspect of the present invention provides a fuel cell assembly system comprising the hydrogen purging system described above.

Compared with the prior art, the invention has the following beneficial effects:

in the hydrogen purging system provided by the invention, the gas supply pipeline group comprises a hydrogen source capable of providing hydrogen and a first control valve for controlling the pressure of the hydrogen flowing out of the hydrogen source, and the hydrogen provided by the hydrogen source enters the fuel cell stack through the stack hydrogen inlet. And part of fluid generated after the hydrogen is subjected to electrochemical reaction in the fuel cell stack flows out through a stack hydrogen outlet and flows into a return air pipeline group, water is separated from the fluid flowing out from the stack hydrogen outlet through a first water-vapor separator, then the fluid is pumped back to a stack hydrogen inlet through a hydrogen circulating pump, the discharged hydrogen is circulated back to the stack hydrogen inlet, and the waste of hydrogen is avoided, so that a hydrogen supply loop is formed.

Particularly, in the invention, the purging pipeline group can store dry hydrogen with certain pressure, after the fuel cell stack stops working, the air supply pipeline group stops working, the dry hydrogen stored in the purging pipeline group can flow into the fuel cell stack through part of pipelines in the air supply pipeline group so as to replace wet hydrogen remained in the fuel cell stack, the replaced wet hydrogen flows out from a hydrogen outlet of the stack, water is separated by the first water-vapor separator, and then the water is pumped into the purging pipeline group by the hydrogen circulating pump so as to be stored for purging in the next shutdown, the hydrogen waste is reduced in the whole process, and the problem that the wet hydrogen stays in the stack to cause icing damage the stack can be solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a hydrogen purging system provided in accordance with one embodiment of the present invention;

FIG. 2 is one of the flowcharts of the control method provided in accordance with one embodiment of the present invention;

FIG. 3 is a second flowchart of a control method according to one embodiment of the present invention;

FIG. 4 is a third flowchart of a control method according to one embodiment of the present invention;

fig. 5 is a connection block diagram of a control module according to one embodiment of the present invention.

Reference numerals

1. A hydrogen source; 2. a first control valve; 3. a fuel cell stack; 4. a first water-vapor separator; 5. a hydrogen circulation pump; 6. a second control valve; 7. a hydrogen chamber; 8. a second water-vapor separator; 9. a third control valve; 10. a fourth control valve; 11. a first sensor group; 12. a second sensor group; 13. and a control module.

Detailed Description

To further clarify the above and other features and advantages of the present invention, a further description of the invention will be rendered by reference to the appended drawings. It should be understood that the specific embodiments presented herein are for purposes of explanation to those skilled in the art and are intended to be illustrative only and not limiting.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

Referring to fig. 1, a first aspect of the present invention provides a hydrogen purging system including a fuel cell stack 3, a supply line set, a return line set, and a purge line set. The fuel cell stack 3 includes a stack hydrogen inlet and a stack hydrogen outlet. The gas supply line group is connected to the hydrogen inlet of the stack and includes a hydrogen source 1 and a first control valve 2 connected in the direction of the gas flow. The return air pipeline group is connected to a hydrogen outlet of the electric pile and comprises a first water-vapor separator 4 and a hydrogen circulating pump 5 which are connected along the air flow direction, and the outlet end of the hydrogen circulating pump 5 is connected between the first control valve 2 and the fuel cell electric pile 3. The purge line group is capable of storing hydrogen and is connected between the hydrogen source 1 and the outlet end of the hydrogen circulation pump 5, and is configured to inject hydrogen toward the stack hydrogen inlet after the fuel cell stack 3 stops operating and to recover the stored hydrogen from the stack hydrogen outlet.

Specifically, the fuel cell stack 3 is a place where electrochemical reaction occurs, and is a core part of the fuel cell. The fuel cell stack 3 mainly obtains hydrogen through a gas supply line group including a hydrogen source 1 capable of supplying hydrogen and a first control valve 2 for controlling the pressure of the hydrogen flowing out of the hydrogen source 1, the hydrogen supplied from the hydrogen source 1 entering the fuel cell stack 3 through a stack hydrogen inlet. Part of the fluid generated after the hydrogen is subjected to electrochemical reaction in the fuel cell stack 3 flows out through a stack hydrogen outlet and flows into a return air pipeline group. It should be noted that, the fluid flowing out from the hydrogen outlet of the electric pile includes liquid water and wet hydrogen, the fluid flowing out from the hydrogen outlet of the electric pile first passes through the first water-vapor separator 4 and then separates out the liquid water, and then is pumped back to the hydrogen inlet of the electric pile by the hydrogen circulating pump 5, and the discharged hydrogen is circulated back to the hydrogen inlet of the electric pile, so that the waste of hydrogen is avoided, and a hydrogen supply loop is formed.

Particularly, in the invention, the purging pipeline group can store hydrogen with certain pressure, after the fuel cell stack 3 stops working, the first control valve 2 closes the hydrogen source 1, the hydrogen stored in the purging pipeline group can flow into the fuel cell stack 3 through part of pipelines in the gas supply pipeline group so as to replace the saturated wet hydrogen remained in the fuel cell stack 3, the replaced saturated wet hydrogen flows out from a hydrogen outlet of the stack, water is separated by the first water-vapor separator 4 and then pumped into the purging pipeline group by the hydrogen circulating pump 5 for storage, so as to be used for purging in the next shutdown, the hydrogen waste is reduced in the whole process, and the problem that the wet hydrogen is retained in the stack to cause icing damage to the stack can be solved.

The hydrogen gas source 1 includes, for example, a hydrogen cylinder, a high-pressure gas tank in which hydrogen gas is stored, and the like, but is not limited thereto. The first control valve 2 is preferably a proportional valve that reduces the pressure of the hydrogen gas discharged from the hydrogen source 1 to reduce the operating pressure of the fuel cell stack 3.

Further, the purge line set includes a hydrogen chamber 7, a second control valve 6, a third control valve 9, and a fourth control valve 10. The hydrogen chamber 7 comprises a first chamber inlet, a second chamber inlet and a chamber outlet, wherein the first chamber inlet is connected to the hydrogen source 1 through a fourth control valve 10, and the second chamber inlet is connected to the outlet end of the hydrogen circulating pump 5 through a second control valve 6; the chamber outlet is connected between the first control valve 2 and the outlet end of the hydrogen circulation pump 5 by a third control valve 9.

Specifically, the hydrogen chamber 7 is configured to store hydrogen at a certain pressure, and in the case where the hydrogen pressure in the hydrogen chamber 7 is insufficient, the hydrogen source 1 is capable of supplying hydrogen and flowing into the hydrogen chamber 7 from the first chamber inlet through the fourth control valve 10 to ensure that the pressure in the hydrogen chamber 7 is constant. After the fuel cell stack 3 stops working, a lot of saturated wet hydrogen exists in the fuel cell stack 3, at the moment, the first control valve 2 is closed, the second control valve 6 and the third control valve 9 are opened, the hydrogen circulation pump 5 is kept open, hydrogen in the hydrogen chamber 7 flows out from the outlet of the chamber and enters the fuel cell stack 3 to replace the saturated wet hydrogen in the fuel cell stack 3, and the saturated wet hydrogen flows back to the hydrogen chamber 7 after passing through the first water-vapor separator 4 and the hydrogen circulation pump 5 for purging in the next shutdown.

It should be noted that, the saturated wet hydrogen gas can be condensed in the hydrogen chamber 7 to reduce the gaseous water content in the hydrogen gas, and a desiccant or the like may be disposed in the hydrogen chamber 7 to ensure the drying of the hydrogen gas. In addition, the hydrogen chamber 7 may be a closed container connected to a pipeline and capable of storing hydrogen.

It should be further noted that the second control valve 6 and the third control valve 9 are used to control the on-off of the pipeline, including, but not limited to, an electric ball valve.

Preferably, the fourth control valve 10 is a constant pressure reducing valve, thus ensuring a constant pressure in the hydrogen chamber 7.

In an embodiment of the invention, the purge line set further comprises a second water-vapor separator 8, the second water-vapor separator 8 being connected between the second chamber inlet and the second control valve 6.

Specifically, the mixture (wet hydrogen and liquid water) displaced from the fuel cell stack 3 is subjected to two water-vapor separations, namely the first water-vapor separator 4 and the second water-vapor separator 8, respectively, to ensure that the hydrogen gas entering the hydrogen chamber 7 is free of liquid water. Of course, in case the hydrogen chamber 7 needs to be exhausted, it is also possible to exhaust it through the second water-vapor separator 8.

In an embodiment of the present invention, the purge line set further includes a first sensor set 11 and a second sensor set 12. The first sensor group 11 is connected to the gas supply line group for detecting the hydrogen pressure and the hydrogen humidity entering the fuel cell stack 3. A second sensor group 12 is connected to the hydrogen chamber 7 for detecting intra-cavity pressure and intra-cavity humidity of the hydrogen chamber 7. Specifically, the hydrogen pressure and hydrogen humidity entering the fuel cell stack 3 are detected by the first sensor group 11, and the intra-cavity pressure and intra-cavity humidity of the hydrogen chamber 7 are detected by the second sensor group 12. Because of the pressure and humidity sensing capability, in an alternative embodiment, the sensor sets are a combination of pressure and humidity sensors.

Referring to fig. 2 to 5, a second aspect of the present invention provides a control method for the above-mentioned hydrogen purging system, the hydrogen purging system further includes a control module 13, the control module 13 is in signal connection with the first control valve 2, the second control valve 6, the third control valve 9, the first water-vapor separator 4 and the hydrogen circulating pump 5, and the control module 13 is configured to:

step S1, acquiring a system shutdown signal, and closing a first control valve 2;

step S2, controlling the hydrogen circulating pump 5 to extend operation under the condition that the first control valve 2 is closed;

step S3, controlling the second control valve 6 and the third control valve 9 to be opened under the condition that the hydrogen pressure is lower than the preset hydrogen pressure;

in step S4, in the case that the hydrogen humidity is lower than the preset hydrogen humidity, the second control valve 6, the third control valve 9 and the hydrogen circulation pump 5 are controlled to be closed.

Before the system is shut down, in order to ensure that the fuel cell operates normally, the hydrogen source 1 supplies hydrogen normally, and accordingly, the first control valve 2 is opened normally. The hydrogen circulation pump 5 normally pumps the wet hydrogen discharged from the stack hydrogen outlet back to the stack hydrogen inlet, and thus the first water-vapor separator 4 and the second hydrogen circulation pump 5 normally operate.

In step S1, a system shutdown signal may be generated by an input unit, such as a key, a touch display screen, etc., and a shutdown operation is triggered to generate the system shutdown signal, at this time, the fuel cell stops operating, and accordingly, the first control valve 2 needs to be closed to shut off the hydrogen source 1, so as to avoid supplying hydrogen to the fuel cell stack 3.

In step S2, under the condition that the first control valve 2 is closed, the hydrogen source 1 cannot provide hydrogen to the fuel cell stack 3, so that the hydrogen circulation pump 5 continues to operate, so that the wet hydrogen and the liquid water discharged from the hydrogen outlet of the stack flow through the first water-vapor separator 4 to separate the liquid water, and the wet hydrogen continues to circulate into the fuel cell stack 3 to carry out the liquid water therein.

In the process of bringing out the liquid water in the fuel cell stack 3 by the wet hydrogen, a part of the hydrogen is consumed through the fuel cell stack 3, and the pressure of the wet hydrogen gradually decreases.

In step S3, in the case where the hydrogen pressure is detected to be lower than the preset hydrogen pressure, it is indicated that most of the liquid water in the fuel cell stack 3 is carried out at this time, and it is difficult to ensure that the remaining liquid water in the fuel cell stack 3 is carried out continuously because the hydrogen pressure is relatively low. At this time, the second control valve 6 and the third control valve 9 are controlled to be opened, the third control valve 9 is opened to open the chamber outlet of the hydrogen chamber 7, and hydrogen in the hydrogen chamber 7 is led out and flows into the hydrogen inlet of the electric pile, so that the residual liquid water and saturated wet hydrogen in the hydrogen chamber 7 are blown out, and as the second control valve 6 is opened, the replaced wet hydrogen can flow back into the hydrogen chamber 7 from the second chamber inlet through the hydrogen circulating pump 5 for the next purging. Of course, the displaced liquid water may be discharged through the first water-vapor separator 4.

It should be noted that the intra-cavity pressure in the hydrogen chamber 7 is greater than the wet hydrogen pressure remaining in the circuit, and the hydrogen circulation pump 5 can ensure a good purge effect in the case of operation.

It can be appreciated that the hydrogen in the hydrogen chamber 7 mixes with the wet hydrogen in the fuel cell stack 3 during the process of replacing the wet hydrogen in the fuel cell stack, so that the hydrogen humidity in the loop can be neutralized to achieve the purpose of reducing the hydrogen humidity. In step S4, when the hydrogen humidity is controlled to be lower than the preset hydrogen humidity, the second control valve 6, the third control valve 9, and the hydrogen circulation pump 5 are controlled to be closed, and the purging is completed.

It should be noted that, the preset hydrogen humidity is a multiple test evaluation value, and the risk of pile failure caused by low-temperature icing can be effectively reduced under the condition that the preset hydrogen humidity is lower than the predicted hydrogen humidity. Next, the hydrogen pressure and the hydrogen humidity can be acquired by the first sensor group 11.

In a specific application, the preset hydrogen pressure is 20Kpa, the preset hydrogen humidity is 50%, and when the first sensor group 11 detects that the hydrogen pressure is lower than 20Kpa, the second control valve 6 and the third control valve 9 are opened to reduce the humidity of the hydrogen in the intermediate loop. When the hydrogen humidity is lower than 50%, the second control valve 6, the third control valve 9 and the hydrogen circulation pump 5 are closed, and the purging is completed.

Further, the operation of extending in controlling the hydrogen circulation pump 5 includes: the hydrogen circulation pump 5 is controlled to operate in the limit operation state for a preset period of time. Specifically, the hydrogen circulation pump 5 is operated for a prolonged period of time throughout the purge process to ensure the circulation of hydrogen in the circuit, wherein the hydrogen circulation pump 5 is operated at a limited operating condition, i.e., maximum rotational speed. For example, after the signal for closing the first control valve 2 is acquired, the hydrogen circulation pump 5 is operated at a maximum rotation speed for 2S, ensuring that the liquid water in the fuel cell stack 3 is rapidly brought out, and the air pressure is rapidly reduced to reach the opening conditions of the second control valve 6 and the third control valve 9 as soon as possible.

In an alternative embodiment, the hydrogen purging system further comprises a second water-vapor separator 8, the second water-vapor separator 8 being connected between the second chamber inlet and the second control valve 6, the second water-vapor separator 8 being in signal connection with the control module 13. The control module 13 is further configured to:

step S10, obtaining intra-cavity pressure and intra-cavity humidity;

step S20, when the intra-cavity pressure is larger than the preset intra-cavity pressure or the intra-cavity humidity is larger than the first preset intra-cavity humidity, the second water-vapor separator 8 is controlled to be opened for air release;

and step S30, when the intra-cavity pressure is smaller than a second preset intra-cavity pressure and the intra-cavity humidity is smaller than the second preset intra-cavity humidity, the second water-vapor separator 8 is controlled to be closed, wherein the second preset pressure is lower than the first preset intra-cavity pressure, and the second preset intra-cavity humidity is lower than the first preset intra-cavity humidity.

In step S10, as described above, the intra-cavity pressure and the intra-cavity humidity in the hydrogen chamber 7 can be determined by the second sensor group 12 to determine that the hydrogen pressure and the hydrogen humidity meet the purge requirement.

In step S20, when the pressure in the chamber is greater than the preset pressure, it indicates that the pressure in the chamber is too high, and at this time, the second water-vapor separator 8 is controlled to exhaust, so as to decompress the hydrogen chamber 7. When the humidity in the cavity is higher than the first preset humidity, the fact that the humidity of hydrogen in the cavity is too high is indicated at the moment, part of the hydrogen in the cavity can be directly discharged through the second water-vapor separator 8 until the pressure in the cavity is lower than the set pressure value of the fourth control valve 10, and the hydrogen source 1 is filled with dry hydrogen to reduce the humidity of the hydrogen.

In step S30, in the case where the intra-cavity pressure and the intra-cavity humidity are determined to satisfy the conditions, the second water-vapor separator 8 is controlled to be turned off, in other words, in the case where the intra-cavity pressure is lower than the second preset intra-cavity pressure and the intra-cavity humidity is lower than the second preset intra-cavity humidity, the hydrogen in the hydrogen chamber 7 satisfies the conditions of the next purge.

It can be seen that the next purging requirement is satisfied by the pressure and humidity in the chamber of the hydrogen chamber 7 through steps S10 to S30. Of course, steps S10 to S30 may be performed before the system is turned off, or may be performed after the system is turned off.

It will be appreciated that the fourth control valve 10 determines the lowest pressure in the hydrogen chamber 7, i.e. the intra-cavity pressure in the hydrogen chamber 7 is always higher than the set value of the fourth control valve 10. I.e. the first preset intra-cavity pressure and the second preset intra-cavity pressure are higher than the set value of the fourth control valve 10.

For example, in a specific application, the fourth control valve 10 has a set point of 50Kpa, a first preset intra-cavity pressure of 60Kpa, a second preset intra-cavity pressure of 55Kpa, a first preset intra-cavity humidity of 40% and a second preset intra-cavity humidity of 30%.

Before the system is shut down, if the pressure in the cavity is higher than 60Kpa, the second water-vapor separator 8 is started to deflate; if the humidity in the cavity is higher than 40%, the second water-vapor separator 8 is turned on to deflate until the pressure in the cavity is lower than 50Kpa, the fourth control valve 10 is turned on, and the hydrogen source 1 supplies hydrogen to the hydrogen chamber 7. In this way, the intra-cavity pressure in the hydrogen chamber 7 is lower than 55Kpa, and the intra-cavity humidity is lower than 30%, so that the second water-vapor separator 8 is ensured to be in a closed state as much as possible.

After the system is shut down, in the process of replacing the hydrogen in the fuel cell stack 3 by the hydrogen in the hydrogen chamber 7, the intra-cavity pressure and the intra-cavity humidity in the hydrogen chamber 7 are dynamically changed, and the second water-vapor separator 8 is opened under the condition of meeting the deflation until the intra-cavity pressure and the intra-cavity humidity in the hydrogen chamber 7 are proper, and the second water-vapor separator 8 is closed.

It will be appreciated that in the on state of the system, there is a situation where the intra-cavity pressure is between 55Kpa and 60Kpa and the intra-cavity humidity is between 30% and 40% for the hydrogen chamber 7, and the second water-vapor separator 8 is in the off state, as described above, the hydrogen chamber 7 has the function of condensing the wet hydrogen to reduce the intra-cavity pressure and the intra-cavity humidity.

After the system is shut down, hydrogen in the fuel cell stack 3 is replaced in the purging process, when the pressure in the cavity is between 55Kpa and 60Kpa and the humidity in the cavity is between 30% and 40%, the second water-vapor separator 8 is in a closed state until the pressure in the cavity is greater than 60Kpa or the humidity in the cavity is greater than 40%, and at this time, the second water-vapor separator 8 is opened until a closing condition is satisfied. During the purge, although it may occur that the second water-vapor separator 8 cannot be triggered to open, wet hydrogen may condense within the hydrogen chamber 7 to further reduce the pressure and humidity.

In an embodiment of the invention, the control module 13 is further configured to:

step S100, acquiring a system start-up signal;

step S200, determining target hydrogen pressure and target hydrogen humidity according to the system load;

step S300, the first control valve 2 and the hydrogen circulation pump 5 are controlled according to the target hydrogen pressure and the target hydrogen humidity, respectively.

In step S100, the system power-on signal can be generated through the input unit, and the description thereof will not be repeated here.

In step S200, the target hydrogen pressure and the target hydrogen humidity may be determined according to the load power, as will be understood by those skilled in the art.

In step S300, when the target hydrogen pressure is too low or too high, the opening of the first control valve 2 may be adjusted to ensure that the pressure entering the hydrogen inlet of the stack is appropriate. When the humidity of the target hydrogen is too high or too low, the rotating speed of the hydrogen circulating pump 5 can be adjusted to adjust the flow of the wet hydrogen, so that the humidity of the hydrogen entering the hydrogen inlet of the electric pile is controlled to be proper.

The water-steam separator is internally provided with a drainage exhaust valve, the air release and drainage can be controlled by opening and closing the drainage exhaust valve, and the opening and closing fingers of the water-steam separator can close the drainage exhaust valve or open the drainage exhaust valve.

In addition, control module 13 includes, but is not limited to, a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, application Specific Integrated Circuits (ASICs), field Programmable Gate Array (FPGA) circuits, any other type of Integrated Circuit (IC), and a state machine, among others.

A third aspect of the present invention provides a fuel cell assembly system comprising the hydrogen purging system described above. In other words, the hydrogen purging system is a subsystem of the fuel cell assembly system, and since the fuel cell assembly system is provided with the hydrogen purging system, it is obvious that the hydrogen purging system has all the advantages brought by the hydrogen purging system, and the detailed description is not repeated here.

Further, it will be understood by those skilled in the art that if all or part of the sub-modules involved in the product provided by the embodiments of the present invention are combined, replaced by fusion, simple variation, mutual transformation, etc., such as placing each component in a moving position; or the products formed by the two are integrally arranged; or a removable design; it is within the scope of the present invention to replace the corresponding components of the present invention with devices/apparatuses/systems that may be combined to form a device/apparatus/system having a specific function.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (10)

1. A hydrogen purging system, the hydrogen purging system comprising:

a fuel cell stack (3) comprising a stack hydrogen inlet and a stack hydrogen outlet;

the gas supply pipeline group is connected to the hydrogen inlet of the electric pile and comprises a hydrogen source (1) and a first control valve (2) which are connected along the gas flow direction;

the return air pipeline group is connected to the hydrogen outlet of the electric pile and comprises a first water-vapor separator (4) and a hydrogen circulating pump (5) which are connected along the air flow direction, and the outlet end of the hydrogen circulating pump (5) is connected between the first control valve (2) and the fuel cell electric pile (3); and

and the purging pipeline group can store hydrogen and is connected between the hydrogen source (1) and the outlet end of the hydrogen circulating pump (5), and is arranged to spray hydrogen towards the hydrogen inlet of the electric pile after the operation of the fuel cell electric pile (3) is stopped and recover and store the hydrogen from the hydrogen outlet of the electric pile.

2. The hydrogen purging system according to claim 1, wherein the purge line set comprises a hydrogen chamber (7), a second control valve (6), a third control valve (9) and a fourth control valve (10);

the hydrogen chamber (7) comprises a first chamber inlet, a second chamber inlet and a chamber outlet, wherein the first chamber inlet is connected with the hydrogen source (1) through a fourth control valve (10), the second chamber inlet is connected with the outlet end of the hydrogen circulating pump (5) through a second control valve (6), and the chamber outlet is connected between the first control valve (2) and the outlet end of the hydrogen circulating pump (5) through a third control valve (9).

3. The hydrogen purging system according to claim 2, wherein the purge line set further comprises a second water-vapor separator (8), the second water-vapor separator (8) being connected between the second chamber inlet and the second control valve (6).

4. Hydrogen purging system according to claim 2, characterized in that the fourth control valve (10) is a constant pressure relief valve.

5. The hydrogen purging system as claimed in claim 2, further comprising a first set of sensors (11) and a second set of sensors (12);

the first sensor group (11) is connected to the gas supply pipeline group for detecting the pressure and the humidity of hydrogen entering the fuel cell stack (3);

the second sensor group (12) is connected to the hydrogen chamber (7) for detecting intra-cavity pressure and intra-cavity humidity of the hydrogen chamber (7).

6. A control method, characterized in that it is applied to a hydrogen purging system according to claim 5, further comprising a control module (13), said control module (13) being in signal connection with said first control valve (2), said second control valve (6), said third control valve (9), said first water-vapor separator (4) and said hydrogen circulation pump (5), said control module (13) being configured to:

acquiring a system shutdown signal, and closing the first control valve (2);

controlling the hydrogen circulation pump (5) to operate in an extending mode under the condition that the first control valve (2) is closed;

controlling the second control valve (6) and the third control valve (9) to be opened under the condition that the hydrogen pressure is lower than a preset hydrogen pressure;

and under the condition that the hydrogen humidity is lower than a preset hydrogen humidity, controlling the second control valve (6), the third control valve (9) and the hydrogen circulation pump (5) to be closed.

7. The control method according to claim 6, characterized in that controlling the hydrogen circulation pump (5) to extend operation includes:

and controlling the hydrogen circulating pump (5) to operate in the limit operation state for a preset period of time.

8. The control method according to claim 6, characterized in that the hydrogen purging system further comprises a second water-vapor separator (8), the second water-vapor separator (8) being connected between the second chamber inlet and the second control valve (6), the second water-vapor separator (8) being in signal connection with the control module (13);

the control module (13) is further configured to:

acquiring the pressure in the cavity and the humidity in the cavity;

controlling the second water-vapor separator (8) to be opened for air release when the pressure in the cavity is larger than the first preset pressure in the cavity or the humidity in the cavity is larger than the first preset humidity in the cavity;

and when the pressure in the cavity is smaller than the second preset pressure in the cavity and the humidity in the cavity is smaller than the second preset humidity in the cavity, controlling the second water-vapor separator (8) to be closed, wherein the second preset pressure is lower than the first preset pressure in the cavity, and the second preset humidity in the cavity is lower than the first preset humidity in the cavity.

9. The control method according to claim 6, characterized in that the control module (13) is further configured to:

acquiring a system starting signal;

determining target hydrogen pressure and target hydrogen humidity according to the system load;

and respectively controlling the first control valve (2) and the hydrogen circulating pump (5) according to the target hydrogen pressure and the target hydrogen humidity.

10. A fuel cell assembly system, characterized in that it comprises a hydrogen purging system according to any one of claims 1 to 5.

Images