CN115224326A - A kind of fuel cell air control method using molecular sieve - Google Patents

Abstract

The invention relates to the field of fuel cells, in particular to a fuel cell air control method using molecular sieves, which comprises arranging the molecular sieve downstream of an air compressor in an air intake pipeline, and arranging the molecular sieve between an intercooler and a fuel cell. Between the stacks, the air compressor is used to increase the adsorption pressure of the molecular sieve, and the molecular sieve adsorbs nitrogen in the air; the air compressor feeds the air adsorbed by the molecular sieve into the inlet of the cathode chamber of the fuel cell stack; reduces the adsorption pressure of the molecular sieve and adsorbs the molecular sieve The nitrogen is desorbed and discharged to the atmosphere through the nitrogen desorption pipeline. By controlling the pressure of the air compressor and the switching of the pipeline, the invention makes the molecular sieve adsorb the air passing through the intercooler, so that the nitrogen is separated from the air and adsorbed to the molecular sieve, so that the oxygen concentration of the air entering the stack is increased, and the performance of the stack is improved. ; Set the air compressor before the molecular sieve, the molecular sieve has a higher working efficiency and a longer life, and the nitrogen adsorbed on the molecular sieve can also be desorbed by adjusting the pressure, and the desorbed nitrogen can be directly used for the purging of the stack , reduce the residual oxygen after purging, and avoid the damage caused by residual oxygen to the stack.

Description

A kind of fuel cell air control method using molecular sieve

technical field

The invention relates to the field of fuel cells, in particular to a fuel cell air control method using molecular sieves.

Background technique

Oxygen is an important reaction raw material for fuel cells. The existing fuel cell system technology only uses ambient air as a raw material without any component treatment. The existing air system consists of air filtration, air compressors, intercoolers, humidifiers. It is equipped with a throttle valve and a three-way valve to adjust the gas pressure. The concentration of oxygen can only be determined by the oxygen concentration in the air flow and cannot be adjusted. Since the increase of oxygen concentration can improve the performance of the stack, the oxygen content of the air in the natural environment is too low, the oxygen concentration of the fuel cell into the stack cannot be increased, which limits the power generation of the stack; in addition, when the stack is purged, the existing The purging mode of the technical stack adopts air purging. After purging, there will be residual oxygen in the air, and the residual oxygen will cause damage to the stack. The above methods are not conducive to improving the efficiency and reliability of the system. However, in the prior art, there is still no technical solution that can better solve the problem of adjusting the oxygen concentration in the air by the fuel cell system.

SUMMARY OF THE INVENTION

In view of the technical defects and technical drawbacks existing in the prior art, the embodiments of the present invention provide a fuel cell air control method using molecular sieves that overcomes the above problems or at least partially solves the above problems. The limitation of oxygen content on the stack.

An embodiment of the present invention provides a fuel cell air control method using molecular sieves, and the fuel cell air control method includes:

The molecular sieve is arranged downstream of the air compressor in the air intake pipeline, and the molecular sieve is arranged between the intercooler and the fuel cell stack. The air compressor is used to increase the adsorption pressure of the molecular sieve, and the molecular sieve adsorbs nitrogen in the air. ;

The air compressor feeds the air adsorbed by the molecular sieve into the inlet of the cathode chamber of the fuel cell stack;

Reduce the adsorption pressure of the molecular sieve, desorb the nitrogen adsorbed by the molecular sieve, and discharge it to the atmosphere through the nitrogen desorption pipeline.

Further, the fuel cell air control method includes:

At least a first molecular sieve and a second molecular sieve are arranged, and the first molecular sieve and the second molecular sieve are respectively connected to the air compressor and the nitrogen desorption pipeline;

When the first molecular sieve is communicated with the air compressor, the second molecular sieve is controlled to communicate with the nitrogen desorption pipeline; when the second molecular sieve is communicated with the air compressor, the first molecular sieve is controlled to communicate with the nitrogen desorption pipeline.

Further, the fuel cell air control method includes:

An air supplementary circuit is provided, the air inlet of the air supplementary circuit is arranged in the air intake pipeline between the air compressor and the intercooler, and the air outlet of the air supplementary circuit is arranged in the air inlet between the molecular sieve and the fuel cell stack. The air intake line adjusts the oxygen concentration entering the fuel cell stack through the air supplementary line.

Further, the fuel cell air control method includes:

Determine the target requirement of oxygen concentration into the stack according to the performance of the fuel cell stack;

By controlling the opening of the air supplementary circuit valve, the air flow of the air intake line and the air supplementary circuit is distributed.

Further, the fuel cell air control method includes controlling the first molecular sieve and the second molecular sieve to communicate alternately with the air compressor according to preset conditions.

Further, the fuel cell air control method includes:

The preset condition is an alternate setting time determined according to the working conditions of the fuel cell and the performance of the molecular sieve. When the alternate setting time is reached, the valves between the first molecular sieve, the second molecular sieve and the air compressor are switched.

Further, the fuel cell air control method includes:

Reduce the adsorption pressure of the molecular sieve by disconnecting the connection between the molecular sieve and the air compressor, so that the molecular sieve can desorb nitrogen;

In the working mode of the fuel cell, the nitrogen is discharged to the atmosphere through the nitrogen discharge branch of the nitrogen desorption pipeline;

In the fuel cell purge mode, nitrogen is fed into the cathode chamber inlet of the fuel cell stack through the nitrogen purge branch of the nitrogen desorption pipeline.

Further, the fuel cell air control method further includes:

Determine the purging timing according to the shutdown state of the fuel cell system;

When it is determined that the purging opportunity is reached, the fuel cell purging mode is activated, and the valve of the nitrogen discharge branch is closed;

Reduce the speed of the air compressor and reduce the opening of the valve downstream of the air compressor.

The embodiments of the present invention can at least partially achieve the following technical effects:

The present invention is a method for controlling the air system of a fuel cell where the molecular sieve is arranged downstream of the air compressor. An intercooler is arranged between the molecular sieve and the air compressor, and the molecular sieve is adsorbed through the intercooler by controlling the pressure of the air compressor and the switching of the pipeline. air from the air compressor, so that nitrogen is separated from the air and adsorbed to the molecular sieve, which increases the oxygen concentration of the air entering the stack, thereby improving the performance of the stack; moreover, if the air compressor is set before the molecular sieve, the molecular sieve works more efficiently Longer life, in addition, the nitrogen adsorbed on the molecular sieve can be desorbed by adjusting the pressure, and the desorbed nitrogen can be directly used for the purging of the stack, reducing the residual oxygen after purging, and avoiding the residual oxygen to the stack. damage.

Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure described in the written description and appended drawings.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the attached image:

FIG. 1 is a schematic diagram of a fuel cell air treatment system utilizing molecular sieves according to an embodiment of the present invention.

FIG. 2 is a flowchart of a fuel cell air control method using molecular sieves according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a low tail emission fuel cell air treatment system using molecular sieves according to an embodiment of the present invention.

FIG. 4 is a flowchart of a method for controlling air in a low tail emission fuel cell using molecular sieves according to an embodiment of the present invention.

5 is a schematic diagram of an oxygen cycle fuel cell air treatment system using molecular sieves according to an embodiment of the present invention.

6 is a flow chart of a method for controlling air in an oxygen-circulating fuel cell using molecular sieves according to an embodiment of the present invention.

Description of the drawings: 1. Fuel cell stack; 2. Air intake pipeline; 3. Nitrogen desorption pipeline; 4. Air supplementary pipeline; 5. Hydrogen tail exhaust pipeline; 6. Oxygen circulation circuit; 21. Air filter 22, air compressor; 23, molecular sieve; 24, intercooler; 25, humidifier; 31, nitrogen discharge branch; 32, nitrogen purge branch; 33, nitrogen tail discharge branch.

Detailed ways

In order to describe in detail the technical content, achieved objects and effects of the present invention, the following descriptions are given with reference to the embodiments and the accompanying drawings.

The drawings and the following description describe alternative embodiments of the invention to teach those skilled in the art how to practice and reproduce the invention. In order to teach the technical solutions of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate that modifications or substitutions derived from these embodiments will fall within the scope of the present invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention.

Molecular sieve adsorption and separation technology has been applied in medical, industrial and other fields. Molecular sieve adsorption is a physical process. The larger the dipole moment of the molecule, the stronger the attraction and adsorption. Nitrogen and oxygen are both quadrupole moments, and nitrogen The quadrupole distance is much larger than that of oxygen, so the force between nitrogen atoms and cations is stronger, and it is preferentially adsorbed. Therefore, molecular sieves can use the difference of each component in the mixed gas to achieve separation. Molecular sieves not only have selective adsorption, but also the adsorption capacity of the adsorbate changes with the adsorption pressure. When the partial pressure of the adsorbate increases, the adsorbent The adsorption capacity of the adsorbate increases; when the partial pressure decreases, the adsorption capacity decreases. In the embodiment of the present invention, the characteristics of molecular sieves are combined with the stacking air of the fuel cell system, and the characteristics of nitrogen and oxygen can be better utilized on the basis of using atmospheric air, thereby improving the efficiency and reliability of the fuel cell system.

Example 1

In this embodiment, a fuel cell air treatment system using molecular sieves is provided, referring to FIG. 1 , the fuel cell air treatment system includes an air intake line 2 connected to the inlet of the cathode chamber of the fuel cell stack 1 , The air intake line 2 is provided with an air filter 21, an air compressor 22, an intercooler 24 and a molecular sieve 23. The air filter 21, the air compressor 22 and the intercooler 24 are connected in sequence, and the molecular sieve 23 is provided with Between the intercooler 24 and the fuel cell stack 1 , the molecular sieve 23 is also connected to the nitrogen desorption pipeline 3 .

Through the structure of this embodiment, nitrogen can be adsorbed on the molecular sieve by the adsorption force of the air compressor. After the nitrogen is separated, the oxygen enters the stack through the air compressor, which increases the oxygen concentration of the cathode, thereby improving the performance of the stack; In the embodiment, the air compressor is arranged before the molecular sieve, and an intercooler is added between the molecular sieve and the air compressor, which can make the molecular sieve work more efficiently and have a longer life. In this embodiment, a dryer or the like may also be provided to adjust the humidity of the incoming gas.

Preferably, the nitrogen desorption pipeline 3 includes a nitrogen purging branch 32 , and both ends of the nitrogen purging branch 32 are respectively connected to the molecular sieve 23 and the inlet of the cathode chamber of the fuel cell stack 1 . In the purging mode, desorbed nitrogen can be used for purging to achieve effective improvement. The original purging scheme uses air as the purging gas, and the air contains oxygen, which is an unfavorable factor. Using nitrogen purging can effectively improve the stack. performance.

Preferably, the fuel cell air handling system further includes an air supplementary circuit 4, and the air inlet of the air supplementary circuit 4 is arranged in the air intake pipe 2 between the air compressor 22 and the intercooler 24, and the air The air outlet of the supplementary path 4 is arranged in the air intake line 2 between the molecular sieve 23 and the fuel cell stack 1 . The air supplementary circuit 4 can effectively and conveniently adjust the oxygen concentration of the air compressor input to the fuel cell stack, ensuring that the oxygen concentration can be adjusted in a larger range, and can meet the needs of different oxygen concentrations. Adjust the oxygen concentration into the stack.

Preferably, the molecular sieve 23 includes at least a first molecular sieve and a second molecular sieve, and the first molecular sieve and the second molecular sieve are connected in parallel. Due to the large pressure fluctuations in adsorption and desorption, alternating use of two molecular sieves can effectively avoid pressure fluctuations and achieve pressure balance. Further, molecular sieves can also be arranged in parallel, for example, 3, 4, 5, or 6, or a plurality of sieves in series and then connected in parallel, and the installation methods can be reasonably configured as required.

Preferably, the nitrogen desorption pipeline 3 further includes a nitrogen discharge branch 31 , the nitrogen discharge branch 31 is communicated with the atmosphere, and a three-way valve is provided on the nitrogen discharge branch 31 . In the working mode of the fuel cell, it can be desorbed by the molecular sieve at the same time, and the nitrogen desorbed by the molecular sieve can be directly discharged to the atmosphere in the working mode.

Preferably, the air supplementary path 4 can also be provided with a valve, and the air intake volume of different paths can be adjusted according to the opening degree of the control valve.

Preferably, valves are respectively arranged between the first molecular sieve and the second molecular sieve and the nitrogen desorption pipeline and the valve of the air compressor. In this embodiment, the first molecular sieve and the second molecular sieve can be opened and closed independently. The first molecular sieve can be connected to the air compressor or the nitrogen desorption pipeline separately. Of course, the opening of the valve can also be adjusted. To adjust the communication relationship between different molecular sieves and each pipeline, for example, the air compressor and valve opening can adjust the adsorption pressure of the first molecular sieve and the second molecular sieve, or each molecular sieve 23 can be provided with different pressure adjustment structures. Preferably, when the first molecular sieve is communicated with the air compressor, the second molecular sieve is communicated with the nitrogen desorption pipeline; when the second molecular sieve is communicated with the air compressor, the first molecular sieve is communicated with the nitrogen desorption pipeline to realize alternate use of molecular sieves , to ensure the pressure balance in the pipeline; and under the premise of uninterrupted operation of the cathode of the fuel cell, the nitrogen adsorption and desorption process of the molecular sieve can be realized online to ensure the continuous use of the molecular sieve.

This embodiment also provides a fuel cell air control method using molecular sieves. First, the molecular sieve 23 is installed, and the air intake pipe 2 connected to the inlet of the cathode chamber of the fuel cell stack is connected to the air filter 21 and the air compressor in sequence. 22. Intercooler 24 and molecular sieve 23, the molecular sieve 23 is arranged downstream of the air compressor 22, and an intercooler is arranged upstream of the molecular sieve, that is, between the intercooler 24 and the fuel cell stack 1; the molecular sieve can be It can be stored in a storage tank, can also be stored in a bag body, or can be installed in a pipeline, with convenient installation and low cost.

The control method after installation includes: using the adsorption force of the air compressor to increase the pressure of the air intake pipeline, thereby increasing the adsorption pressure of the molecular sieve, increasing the adsorption force of the molecular sieve, so that the molecular sieve adsorbs and separates the nitrogen in the air, so as to obtain an increase in the oxygen concentration. The air after adsorption, the air compressor then inputs the air after adsorption into the inlet of the cathode chamber of the fuel cell stack, wherein the concentration of oxygen in the air after adsorption into the stack is higher than the concentration of oxygen in atmospheric air, and its concentration can be Adjust by controlling the parameters of the air compressor.

Preferably, in order to ensure the pressure balance and make the system more stable, the molecular sieve can be set as the first molecular sieve and the second molecular sieve in parallel, and the first molecular sieve and the second molecular sieve are alternately used to achieve the pressure balance in the nitrogen adsorption and desorption process; For example, when the first molecular sieve is adsorbed to a certain extent, alternate molecular sieves, so that the second molecular sieve is in the fuel cell working mode for nitrogen adsorption, while the first molecular sieve is used for nitrogen desorption. run.

Preferably, in order to be more conducive to the adjustment of the oxygen concentration in the inlet gas, and to expand the adjustment range, an air supplementary circuit is also arranged downstream of the air compressor, and the air inlet of the air supplementary circuit is provided at the air compressor and the intercooler. The air intake pipeline between the air supply pipelines, the air outlet of the air supplementary pipeline is arranged in the air intake pipeline between the molecular sieve and the fuel cell stack, and the oxygen concentration entering the fuel cell stack is adjusted through the air supplementary pipeline. It can also be adjusted via an intercooler.

Preferably, the adsorption pressure of the molecular sieve can be reduced by an air compressor and other equipment to realize the desorption of nitrogen adsorbed by the molecular sieve; the desorbed nitrogen is input into the nitrogen desorption pipeline, and the nitrogen is passed through the nitrogen desorption pipeline in the working mode of the fuel cell. The nitrogen discharge branch is discharged to the atmosphere; in the fuel cell purging mode, nitrogen is input into the cathode chamber inlet of the fuel cell stack through the nitrogen purging branch of the nitrogen desorption pipeline.

Preferably, as shown in FIG. 2, a fuel cell air control method using molecular sieve is provided, comprising:

S101 starts the fuel cell stack, and opens the valve of the nitrogen discharge branch in the fuel cell air handling system;

S102 determines the target requirement of oxygen concentration into the stack according to the performance of the fuel cell stack;

S103 distributes the air flow of the air intake pipe into the intercooler and the air supplementary circuit by controlling the valve opening;

S104 controls the first molecular sieve and the second molecular sieve to alternately communicate with the air compressor according to preset conditions;

S105 judges whether the purging timing is reached, if so, go to S106; if not, go to S104;

S106 closes the valve of the nitrogen discharge branch in the fuel cell air handling system;

S107 Reduce the speed of the air compressor and reduce the opening of the valve downstream of the air compressor;

In S108, it is determined that the purging is completed, and the power is turned off.

In this embodiment, the molecular sieve is arranged downstream of the air compressor in the air intake pipeline, an intercooler is added between the molecular sieve and the air compressor, and a dryer can also be added, and the air compressor is used to increase the size of one of the molecular sieves. The adsorption pressure enables the molecular sieve to automatically absorb a large amount of nitrogen in the air; the air compressor feeds the air (with high oxygen concentration) adsorbed by the molecular sieve into the inlet of the cathode chamber of the fuel cell stack; in S101, different pipelines can be set, By controlling the valve, the gas passing through the molecular sieve is matched into the air compressor or discharged to the atmosphere; in S102, according to the performance requirements of the stack, it is pre-calculated how much oxygen concentration can be improved corresponding to how much the stack performance can be improved, and in S103 according to the preset target The flow distribution is carried out. Among them, the high temperature and high pressure gas entering the intercooler is cooled by the intercooler and then passed through the molecular sieve, which can increase the service life of the molecular sieve. The molecular sieve performs nitrogen adsorption, and the output gas is high-concentration oxygen. The concentration can be obtained by calculation or experiment. The gas passing through the air supplementary path is the air in the atmosphere, and the oxygen concentration can be known. According to the preset oxygen concentration requirement, the gas flow of different pipelines can be calculated separately, and then the valve is opened according to the flow distribution. In step S104, the preset condition can be a preset time, for example, when it reaches 1 hour, switch the molecular sieve valve, connect the molecular sieve in adsorption with the nitrogen discharge branch, and the other molecular sieve, that is, the molecular sieve after desorption and The air compressor is connected and used alternately. The molecular sieve connected with the nitrogen discharge branch will automatically desorb the nitrogen adsorbed by the molecular sieve due to the decrease of the adsorption pressure, and will be discharged to the atmosphere through the nitrogen desorption pipeline. That is, the molecular sieve desorbs the adsorbed nitrogen from the molecular sieve during decompression, and discharges it back into the ambient air. When the next pressurization is performed, nitrogen can be re-adsorbed to increase the oxygen concentration. The whole process forms a periodic dynamic cycle process; in S106 . In S107, in the fuel cell purge mode, the nitrogen desorbed from the molecular sieve can be used for purging according to the purge flow requirement, and the nitrogen purge branch of the nitrogen desorption pipeline is input to the inlet of the cathode chamber of the fuel cell stack. , so as to avoid residual oxygen in the purging; among them, slowly reducing the speed of the air compressor and reducing the opening of the valve downstream of the air compressor can avoid the phenomenon of air compressor surge and ensure that the nitrogen purging process is more stable.

Based on the same inventive concept, the present embodiment also provides a fuel cell system and a vehicle. Since the principle of the problem solved by the fuel cell system and the vehicle is similar to the fuel cell air treatment system using molecular sieves in the foregoing embodiments, the present embodiment For the implementation of the embodiment, reference may be made to the implementation of the aforementioned fuel cell air treatment system using molecular sieves, and repeated details will not be repeated.

An embodiment of the present invention further provides a fuel cell system, including a fuel cell stack, the inlet of the cathode chamber of the fuel cell stack and the air intake pipe of the fuel cell air treatment system using molecular sieve described in any one of the above embodiments The road is connected. The fuel cell system of this embodiment can adjust the concentration of oxygen and has high efficiency and reliability.

Embodiments of the present invention also provide a vehicle, the vehicle including the fuel cell system described in any of the above embodiments.

Example 2

Based on the same inventive concept as in Embodiment 1, this embodiment provides a low tail-emission fuel cell air treatment system using molecular sieves. Referring to FIG. 3 , it includes an air intake line 2 connected to the inlet of the cathode chamber of the fuel cell stack 1 , The air intake line 2 is provided with an air filter 21, an air compressor 22, an intercooler 24 and a molecular sieve 23. The air filter 21, the air compressor 22 and the intercooler 24 are connected in sequence, and the molecular sieve 23 is provided with Between the intercooler 24 and the fuel cell stack 1, the molecular sieve 23 is also connected to the nitrogen desorption pipeline 3, and the nitrogen desorption pipeline 3 is provided with a nitrogen tail exhaust branch 33, and the nitrogen tail The exhaust branch 33 communicates with the hydrogen tail exhaust pipeline 5 of the fuel cell stack. In this embodiment, adding an intercooler and a dryer between the molecular sieve and the air compressor can not only increase the oxygen concentration, but also use the nitrogen from the molecular sieve to reduce the hydrogen concentration in the tail exhaust through the nitrogen tail exhaust branch. The intercooler also The oxygen concentration in the stack can be adjusted through the air supplementary circuit.

Preferably, the nitrogen desorption pipeline 3 includes a nitrogen purging branch 32 , and both ends of the nitrogen purging branch 32 are respectively connected to the molecular sieve 23 and the inlet of the cathode chamber of the fuel cell stack 1 . In the purging mode, desorbed nitrogen can be used for purging to achieve effective improvement. The original purging scheme uses air as the purging gas, and the air contains oxygen, which is an unfavorable factor. Using nitrogen purging can effectively improve the stack. performance.

Preferably, the low tail exhaust fuel cell air treatment system further includes an air supplementary circuit 4, and the air inlet of the air supplementary circuit 4 is arranged in the air intake line 2 between the air compressor 22 and the intercooler 24, The air outlet of the air supplementary circuit 4 is arranged in the air intake line 2 between the molecular sieve 23 and the fuel cell stack 1; the air supplementary circuit 4 directly introduces the air from the air compressor outlet into the stack, which can more effectively and conveniently adjust the fuel input. The oxygen concentration of the battery stack ensures that the range in which the oxygen concentration can be adjusted becomes larger, which can meet the needs of different oxygen concentrations.

Preferably, the low tail exhaust fuel cell air treatment system further includes an air supplementary circuit 4 and a humidifier 25, the humidifier 5 is arranged between the molecular sieve 23 and the fuel cell stack 1, and the air supplementary circuit 4 The air inlet is provided in the air intake line 2 between the air compressor 22 and the intercooler 24 , and the air outlet of the air supplementary line 4 is provided in the air intake line 2 between the molecular sieve 23 and the humidifier 25 . In this embodiment, setting a humidifier behind the molecular sieve can directly increase the humidity of the incoming oxygen.

Preferably, the molecular sieve 23 includes at least a first molecular sieve and a second molecular sieve, and the first molecular sieve and the second molecular sieve are connected in parallel. Due to the large pressure fluctuations in adsorption and desorption, alternating use of two molecular sieves can effectively avoid pressure fluctuations and achieve pressure balance. Further, the molecular sieves can also be set up in parallel, or in parallel after a plurality of series, and the installation method can be reasonably configured as required.

Preferably, in order to facilitate control, such as switching between the purging mode and the normal working mode, a three-way valve may be provided on the nitrogen desorption pipeline 3, the nitrogen tail exhaust branch 33, and the nitrogen purging branch 32, respectively. Each pipeline is equipped with a corresponding valve, or a three-way valve can be set on one of the pipelines. In the fuel cell working mode, the molecular sieve desorption can be carried out at the same time, and the nitrogen desorbed by the molecular sieve is output through the hydrogen tailpipe of the fuel cell stack, thereby reducing the concentration of hydrogen and improving the safety performance.

This embodiment also provides an air control method for a low tail exhaust fuel cell using molecular sieves. First, the air filter on the air intake pipeline connected to the inlet of the cathode chamber of the fuel cell stack, the air compressor intercooler and the molecular sieve are sequentially connected. Connect the molecular sieve between the intercooler and the fuel cell stack; set the nitrogen desorption pipeline of the molecular sieve, and connect the nitrogen tail exhaust branch of the nitrogen desorption pipeline to the fuel cell stack. The hydrogen tail exhaust pipeline is connected, so that the desorbed nitrogen is discharged through the hydrogen tail exhaust pipeline.

The treatment process after installation includes: increasing the adsorption pressure of the molecular sieve by the adsorption force of the air compressor, the molecular sieve adsorbs the nitrogen in the air, separates the nitrogen from the air, and separates the adsorbed air, and the oxygen concentration in the air after adsorption is high. , the air compressor will input the adsorbed air into the inlet of the cathode chamber of the fuel cell stack; ensure that the oxygen concentration in the stack is increased and can be controlled; when the adsorption pressure of the molecular sieve is reduced, the molecular sieve will desorb the adsorbed nitrogen, and the The desorbed nitrogen is fed into the hydrogen tailpipe of the fuel cell stack through the nitrogen tailpipe branch provided on the nitrogen desorption pipeline.

Preferably, in order to ensure the pressure balance and make the system more stable, the molecular sieve can be set as the first molecular sieve and the second molecular sieve in parallel, and the first molecular sieve and the second molecular sieve are alternately used to achieve the pressure balance in the nitrogen adsorption and desorption process; For example, when the first molecular sieve is adsorbed to a certain extent, alternate molecular sieves, so that the second molecular sieve is in the fuel cell working mode for nitrogen adsorption, while the first molecular sieve is used for nitrogen desorption. run.

Preferably, in order to be more conducive to the adjustment of the oxygen concentration in the inlet gas and to expand the adjustment range, an air supplementary circuit and a humidifier are arranged between the fuel cell stack and the molecular sieve, and the humidifier is arranged between the molecular sieve and the electric sieve. Between the stacks, the air inlet of the air supplementary path is arranged in the air inlet line between the air compressor and the intercooler, and the air outlet of the air supplementary path is arranged in the air inlet between the molecular sieve and the humidifier. Air line.

The oxygen concentration entering the fuel cell stack is regulated by an air make-up circuit.

Preferably, the adsorption pressure of the molecular sieve can be reduced by an air compressor and other equipment to realize the desorption of nitrogen adsorbed by the molecular sieve; the desorbed nitrogen is input into the nitrogen desorption pipeline, and the nitrogen is passed through the nitrogen desorption pipeline in the working mode of the fuel cell. The nitrogen tail exhaust branch is input into the hydrogen tail exhaust pipe and discharged; in the fuel cell purging mode, nitrogen is input into the cathode chamber inlet of the fuel cell stack through the nitrogen purging branch of the nitrogen desorption pipeline.

Preferably, as shown in FIG. 4 , a method for controlling air in a low tail exhaust fuel cell using molecular sieves is provided, including:

S201 starts the fuel cell stack, and opens the valve of the nitrogen discharge branch in the low tail exhaust fuel cell air handling system;

S202 determines the target requirement of oxygen concentration into the stack according to the performance of the fuel cell stack;

S203 distributes the air flow of the air intake pipe into the intercooler and the air supplementary circuit by controlling the valve opening;

S204 discharges the desorbed nitrogen through the hydrogen tailpipe;

S205 controls the first molecular sieve and the second molecular sieve to communicate alternately with the air compressor according to preset conditions;

S206 judges whether the purging timing is reached, if so, go to S207; if not, go to S205;

S207 Close the valve of the nitrogen discharge branch in the low tail exhaust fuel cell air handling system;

S208 reduces the speed of the air compressor and reduces the opening of the valve downstream of the air compressor;

S209 determines that the purging is over, and shuts down.

In this embodiment, the nitrogen adsorbed by the molecular sieve can be desorbed by itself by reducing the pressure, or it can be desorbed by an external pressure reduction or other methods. The desorbed nitrogen is input through the nitrogen tail exhaust branch set on the nitrogen desorption pipeline. The hydrogen tailpipe of the fuel cell stack can reduce the concentration of hydrogen in the tailpipe. The purging timing in S206 is that the fuel cell stack is in the shutdown state, and it is necessary to avoid water retention in the stack, which will affect the performance; in S209, the timing for the end of purging is determined according to the fuel cell system. ice.

Based on the same inventive concept, the present embodiment also provides a fuel cell system and a vehicle, because the principle of the problem solved by the fuel cell system and the vehicle is similar to the low tail exhaust fuel cell air treatment system using molecular sieves in the foregoing embodiment Therefore, for the implementation of this embodiment, reference may be made to the implementation of the aforementioned low-tail exhaust fuel cell air treatment system using molecular sieves, and repeated details will not be repeated.

An embodiment of the present invention further provides a fuel cell system, including a fuel cell stack, the inlet of the cathode chamber of the fuel cell stack is connected to the air treatment system of the low tail exhaust fuel cell air treatment system using molecular sieve according to any one of the above embodiments. The air intake lines are connected. The fuel cell system of this embodiment can adjust the concentration of oxygen, has high efficiency and reliability, and can effectively reduce the concentration of hydrogen emissions.

Embodiments of the present invention also provide a vehicle, the vehicle including the fuel cell system described in any of the above embodiments.

Example 3

Based on the same inventive concept as Embodiment 1, this embodiment provides an oxygen cycle fuel cell air treatment system using molecular sieves. Referring to FIG. 5 , it includes an air intake line 2 connected to the inlet of the cathode chamber of the fuel cell stack 1 , and The air outlet pipeline connected to the outlet of the cathode chamber of the fuel cell stack, the air inlet pipeline 2 is provided with an air filter 21, an air compressor 22, an intercooler 24 and a molecular sieve 23. The compressor 22 and the intercooler 24 are connected in sequence, the molecular sieve 23 is arranged between the intercooler 24 and the fuel cell stack 1, and the molecular sieve 23 is also provided with a degassing port connected to the nitrogen desorption pipeline 3, so The outlet of the air outlet pipeline is connected with the air intake pipeline downstream of the air compressor to form an oxygen circulation pipeline 6 . In this embodiment, while increasing the oxygen concentration, oxygen can be used more effectively through the designed oxygen circulation pipeline, and the oxygen humidity of the stack can be introduced into the stack, thereby increasing the humidification of the gas entering the stack. Among them, the oxygen circulation circuit can use the oxygen circulation pump or the ejector and other equipment to make more effective use of the oxygen circulation and improve the oxygen utilization rate.

Preferably, the nitrogen desorption pipeline 3 includes a nitrogen purging branch 32 , and both ends of the nitrogen purging branch 32 are respectively connected to the molecular sieve 23 and the inlet of the cathode chamber of the fuel cell stack 1 . In the purging mode, desorbed nitrogen can be used for purging to achieve effective improvement. The original purging scheme uses air as the purging gas, and the air contains oxygen, which is an unfavorable factor. Using nitrogen purging can effectively improve the stack. performance.

Preferably, the nitrogen desorption pipeline 3 includes a nitrogen tail exhaust branch 33 , and both ends of the nitrogen exhaust branch 33 are respectively connected with the molecular sieve 23 and the hydrogen exhaust pipeline 5 of the fuel cell stack 1 . In the normal working mode, the nitrogen gas from the molecular sieve can be used to reduce the hydrogen concentration in the tail exhaust through the nitrogen exhaust branch 33 .

Preferably, the low tail exhaust fuel cell air treatment system further includes an air supplementary circuit 4, and the air inlet of the air supplementary circuit 4 is arranged in the air intake line 2 between the air compressor 22 and the intercooler 24, The air outlet of the air supplementary circuit 4 is arranged in the air intake pipeline 2 between the molecular sieve 23 and the fuel cell stack 1; the air supplementary circuit 4 directly introduces the high-pressure air from the air compressor outlet into the stack, which can more effectively and conveniently adjust the air intake. The oxygen concentration of the fuel cell stack ensures that the adjustable range of the oxygen concentration becomes larger, which can meet the needs of different oxygen concentrations.

Preferably, the low tail exhaust fuel cell air treatment system further includes an air supplementary circuit 4 and a humidifier 25, the humidifier 5 is arranged between the molecular sieve 23 and the fuel cell stack 1, and the air supplementary circuit 4 The air inlet is provided in the air intake line 2 between the air compressor 22 and the intercooler 24 , and the air outlet of the air supplementary line 4 is provided in the air intake line 2 between the molecular sieve 23 and the humidifier 25 .

Preferably, the molecular sieve 23 includes at least a first molecular sieve and a second molecular sieve, and the first molecular sieve and the second molecular sieve are connected in parallel. Due to the large pressure fluctuations in adsorption and desorption, alternating use of two molecular sieves can effectively avoid pressure fluctuations and achieve pressure balance. Further, the molecular sieves can also be set up in parallel, or in parallel after a plurality of series, and the installation method can be reasonably configured as required.

Preferably, in order to facilitate control, such as switching between the purging mode and the normal working mode, a three-way valve may be provided on the nitrogen desorption pipeline 3, the nitrogen tail exhaust branch 33, and the nitrogen purging branch 32, respectively. Each pipeline is equipped with a corresponding valve, or a three-way valve can be set on one of the pipelines. In the fuel cell working mode, the molecular sieve desorption can be carried out at the same time, and the nitrogen desorbed by the molecular sieve is output through the hydrogen tailpipe of the fuel cell stack, thereby reducing the concentration of hydrogen and improving the safety performance.

This embodiment also provides an oxygen circulation fuel cell air control method using molecular sieves. First, the air filter, the air compressor intercooler and the molecular sieve on the air intake pipeline connected to the inlet of the cathode chamber of the fuel cell stack are sequentially connected , the molecular sieve is arranged between the intercooler and the fuel cell stack; the nitrogen desorption pipeline of the molecular sieve is set, and the air outlet pipeline of the fuel cell stack is connected with the air outlet pipeline arranged downstream of the air compressor. The air intake pipeline is connected to form an oxygen circulation pipeline 6 .

The treatment process after installation includes: increasing the adsorption pressure of the molecular sieve by the adsorption force of the air compressor, the molecular sieve adsorbs the nitrogen in the air, separates the nitrogen from the air, and separates the adsorbed air, and the oxygen concentration in the air after adsorption is high. , the air compressor feeds the adsorbed air into the inlet of the cathode chamber of the fuel cell stack, and the air outlet pipeline of the fuel cell is connected with the air inlet pipeline to form an oxygen circulation pipeline, which will be discharged from the stack. Oxygen with high humidity is brought into the intake pipeline, thereby increasing the humidity of the gas entering the stack, which can effectively humidify the gas entering the stack; ensure that the oxygen concentration entering the stack is increased and can be controlled; when the adsorption pressure of the molecular sieve is reduced, The molecular sieve desorbs the adsorbed nitrogen, and the desorbed nitrogen is removed through the nitrogen desorption pipeline.

Preferably, in order to ensure the pressure balance and make the system more stable, the molecular sieve can be set as the first molecular sieve and the second molecular sieve in parallel, and the first molecular sieve and the second molecular sieve are alternately used to achieve the pressure balance in the nitrogen adsorption and desorption process; For example, when the first molecular sieve is adsorbed to a certain extent, alternate molecular sieves, so that the second molecular sieve is in the fuel cell working mode for nitrogen adsorption, while the first molecular sieve is used for nitrogen desorption. run.

Preferably, in order to be more conducive to the adjustment of the oxygen concentration in the inlet gas and to expand the adjustment range, an air supplementary circuit and a humidifier are arranged between the fuel cell stack and the molecular sieve, and the humidifier is arranged between the molecular sieve and the electric sieve. Between the stacks, the air inlet of the air supplementary path is arranged in the air inlet line between the air compressor and the intercooler, and the air outlet of the air supplementary path is arranged in the air inlet between the molecular sieve and the humidifier. The gas pipeline is used to adjust the oxygen concentration entering the fuel cell stack through the air supplementary circuit.

Preferably, the adsorption pressure of the molecular sieve can be reduced by an air compressor and other equipment to realize the desorption of nitrogen adsorbed by the molecular sieve; the desorbed nitrogen is input into the nitrogen desorption pipeline, and the nitrogen is passed through the nitrogen desorption pipeline in the working mode of the fuel cell. The nitrogen tail exhaust branch is input into the hydrogen tail exhaust pipe and discharged; in the fuel cell purging mode, nitrogen is input into the cathode chamber inlet of the fuel cell stack through the nitrogen purging branch of the nitrogen desorption pipeline.

Preferably, as shown in FIG. 6 , a method for controlling the air of an oxygen circulation low tail exhaust fuel cell using molecular sieves is provided, including:

S301 starts the fuel cell stack, and opens the valve of the nitrogen discharge branch in the oxygen cycle fuel cell air treatment system;

S302 determines the target requirement of oxygen concentration into the stack according to the performance of the fuel cell stack;

S303 distributes the air flow of the air intake pipe into the intercooler and the air supplementary circuit by controlling the valve opening;

S304 discharges the desorbed nitrogen gas through the hydrogen tailpipe;

S305 controls the first molecular sieve and the second molecular sieve to communicate alternately with the air compressor according to preset conditions;

S306 controls to open the valve in the oxygen circulation pipeline, and input the oxygen discharged from the stack into the air intake pipeline;

S307 judges whether the purging timing is reached, if so, go to S308; if not, go to S305;

S308 closes the valve of the nitrogen discharge branch in the oxygen cycle fuel cell air treatment system;

S309 reduces the speed of the air compressor and reduces the opening of the valve downstream of the air compressor;

S310 determines that the purging is over, and shuts down.

In this embodiment, in S306, in addition to increasing the oxygen concentration, an oxygen circulation pipeline is also designed, which can more effectively utilize the oxygen humidity of the stack to humidify the gas entering the stack. It can also be combined with a humidifier to control the humidity of the incoming gas, which is more conducive to adjustment and cost reduction.

Based on the same inventive concept, this embodiment also provides a fuel cell system and a vehicle. Since the principle of the problem solved by the fuel cell system and the vehicle is similar to the oxygen cycle fuel cell air treatment system using molecular sieves in the foregoing embodiment, Therefore, for the implementation of this embodiment, reference may be made to the implementation of the aforementioned oxygen cycle fuel cell air treatment system using molecular sieves, and repeated details will not be repeated.

An embodiment of the present invention further provides a fuel cell system, including a fuel cell stack, the inlet of the cathode chamber of the fuel cell stack is connected to the air of the oxygen cycle fuel cell air treatment system using molecular sieve described in any one of the above embodiments The intake pipes are connected. The fuel cell system of this embodiment can adjust the concentration of oxygen, has high efficiency and reliability, and can ensure the humidity of the oxygen entering the stack.

Embodiments of the present invention also provide a vehicle, the vehicle including the fuel cell system described in any of the above embodiments.

In the above embodiment, the corresponding molecular sieve amount or other parameters can be matched according to the oxygen concentration requirements, so as to improve the stack performance according to the requirements, the air supplementary circuit can be used to adjust the oxygen concentration in the stack, and nitrogen purging can be realized to reduce the tail exhaust. The hydrogen concentration, in implementation 3, can also realize the circulation of oxygen, and it is more convenient to adjust the humidity of the incoming gas.

Words such as "first", "second", etc. used in the description and the claims are used to modify the corresponding element, which does not mean that the element has any ordinal number, nor does it mean that a certain element is related to the corresponding element. The order of another element, the use of the ordinal numbers is only used to clearly distinguish one element with a certain designation from another element with the same designation.

Similarly, it is to be understood that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or its description. However, this method of the invention should not be construed to reflect the intention that the invention as claimed requires more features than are expressly recited in each claim. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.

Claims (8)

1. A fuel cell air control method utilizing molecular sieve is characterized in that, described fuel cell air control method comprises, The molecular sieve is arranged downstream of the air compressor in the air intake pipeline, and the molecular sieve is arranged between the intercooler and the fuel cell stack. The air compressor is used to increase the adsorption pressure of the molecular sieve, and the molecular sieve adsorbs nitrogen in the air. ; The air compressor feeds the air adsorbed by the molecular sieve into the inlet of the cathode chamber of the fuel cell stack; Reduce the adsorption pressure of the molecular sieve, desorb the nitrogen adsorbed by the molecular sieve, and discharge it to the atmosphere through the nitrogen desorption pipeline. 2. The fuel cell air control method using molecular sieves according to claim 1, wherein the fuel cell air control method comprises: At least a first molecular sieve and a second molecular sieve are arranged, and the first molecular sieve and the second molecular sieve are respectively connected to the air compressor and the nitrogen desorption pipeline; When the first molecular sieve is communicated with the air compressor, the second molecular sieve is controlled to communicate with the nitrogen desorption pipeline; when the second molecular sieve is communicated with the air compressor, the first molecular sieve is controlled to communicate with the nitrogen desorption pipeline. 3. The fuel cell air control method using molecular sieves according to claim 1, wherein the fuel cell air control method comprises: An air supplementary circuit is provided, the air inlet of the air supplementary circuit is arranged in the air intake pipeline between the air compressor and the intercooler, and the air outlet of the air supplementary circuit is arranged in the air inlet between the molecular sieve and the fuel cell stack. The air intake line adjusts the oxygen concentration entering the fuel cell stack through the air supplementary line. 4. The fuel cell air control method using molecular sieves according to claim 3, wherein the fuel cell air control method comprises: Determine the target requirement of oxygen concentration into the stack according to the performance of the fuel cell stack; By controlling the opening of the air supplementary circuit valve, the air flow of the air intake line and the air supplementary circuit is distributed. 5 . The fuel cell air control method using molecular sieves according to claim 2 , wherein the fuel cell air control method comprises: controlling the first molecular sieve and the second molecular sieve to communicate alternately with the air compressor according to preset conditions. 6 . 6. The fuel cell air control method using molecular sieves according to claim 5, wherein the fuel cell air control method comprises: The preset condition is an alternate setting time determined according to the working conditions of the fuel cell and the performance of the molecular sieve. When the alternate setting time is reached, the valves between the first molecular sieve, the second molecular sieve and the air compressor are switched. 7. The fuel cell air control method using molecular sieves according to claim 1, wherein the fuel cell air control method comprises: Reduce the adsorption pressure of the molecular sieve by disconnecting the connection between the molecular sieve and the air compressor, so that the molecular sieve can desorb nitrogen; In the working mode of the fuel cell, the nitrogen is discharged to the atmosphere through the nitrogen discharge branch of the nitrogen desorption pipeline; In the fuel cell purge mode, nitrogen is fed into the cathode chamber inlet of the fuel cell stack through the nitrogen purge branch of the nitrogen desorption pipeline. 8. The fuel cell air control method using molecular sieves according to claim 7, wherein the fuel cell air control method further comprises: Determine the purging timing according to the shutdown state of the fuel cell system; When it is determined that the purging timing is reached, the fuel cell purging mode is activated, and the valve of the nitrogen discharge branch is closed; Reduce the speed of the air compressor and reduce the opening of the valve downstream of the air compressor.

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