阅读说明：本技术 一种具有双极尾气压力联动平衡功能的燃料电池系统 (Fuel cell system with bipolar tail gas pressure linkage balance function ) 是由 邓波 汤浩 宋亚婷 于 2021-08-04 设计创作，主要内容包括：本发明提供一种具有双极尾气压力联动平衡功能的燃料电池系统,属于燃料电池技术领域,包括电堆模块、氢气子系统、空气子系统、热管理子系统、尾气子系统和附属控制系统,尾气子系统包括双极尾气压力联动平衡装置、阴阳极尾气切断阀、阴阳极尾气背压阀、阴阳极尾气排液阀、系统阴阳极尾气排出口、冷凝水排出口以及管路,双极尾气压力联动平衡装置包括壳体、弹性隔膜、隔膜固定件、阴阳极尾气腔体、阴阳极尾气进口、阴阳极尾气出口和阴阳极腔排液口。本发明利用双极尾气压力联动平衡装置将阴阳极尾气物理隔离,同时通过背压调节过程实现阴阳极出堆压力的平衡,提高燃料电池系统在全功率范围内压力稳定性,适用于快速变载运行过程及紧急停机过程。(The invention provides a fuel cell system with a bipolar tail gas pressure linkage balancing function, which belongs to the technical field of fuel cells and comprises a galvanic pile module, a hydrogen subsystem, an air subsystem, a heat management subsystem, a tail gas subsystem and an auxiliary control system, wherein the tail gas subsystem comprises a bipolar tail gas pressure linkage balancing device, a cathode and anode tail gas stop valve, a cathode and anode tail gas back pressure valve, a cathode and anode tail gas discharge valve, a system cathode and anode tail gas discharge port, a condensate water discharge port and a pipeline, and the bipolar tail gas pressure linkage balancing device comprises a shell, an elastic diaphragm, a diaphragm fixing part, a cathode and anode tail gas cavity, a cathode and anode tail gas inlet, a cathode and anode tail gas outlet and a cathode and anode cavity liquid discharge port. The invention physically isolates the cathode and anode tail gases by using the bipolar tail gas pressure linkage balancing device, realizes the balance of the cathode and anode stack outlet pressure through the backpressure regulation process, improves the pressure stability of the fuel cell system in the full power range, and is suitable for the rapid load-changing operation process and the emergency shutdown process.)

1. A fuel cell system with a bipolar tail gas pressure linkage balance function comprises a galvanic pile module (100), and a hydrogen subsystem (200), an air subsystem (300), a heat management subsystem (400), a tail gas subsystem (500) and an auxiliary control system (600) which are connected with the galvanic pile module (100), and is characterized in that the tail gas subsystem (500) comprises a bipolar tail gas pressure linkage balance device (5), an anode tail gas cut-off valve (501), an anode tail gas backpressure valve (502), a cathode tail gas cut-off valve (503), a cathode tail gas backpressure valve (504), an anode tail gas drain valve (508), a cathode tail gas drain valve (509), a system anode tail gas discharge port (505), a system cathode tail gas discharge port (506), a condensed water discharge port (507) and a pipeline for connection;

the bipolar tail gas pressure linkage balancing device (5) comprises a shell (520), an elastic diaphragm (521), a diaphragm fixing piece (522), an anode tail gas cavity (523), a cathode tail gas cavity (524), an anode tail gas inlet (525), an anode tail gas outlet (526), a cathode tail gas inlet (527), a cathode tail gas outlet (528), an anode cavity liquid outlet (529) and a cathode cavity liquid outlet (530);

the elastic diaphragm (521) is fixed through a diaphragm fixing piece (522), and the interior of the shell (520) is divided into an anode tail gas cavity (523) and a cathode tail gas cavity (524); the anode tail gas inlet (525) and the cathode tail gas inlet (527) are respectively connected with the pile anode tail gas discharge pipe (71) and the pile cathode tail gas discharge pipe (72); the anode tail gas outlet (526) is connected to a system anode tail gas outlet (505) through an anode tail gas backpressure valve (502) by a pipeline, and the anode tail gas stop valve (501) is connected with the anode tail gas backpressure valve (502) in parallel; the cathode tail gas outlet (528) is connected to a system cathode tail gas outlet (506) through a cathode tail gas backpressure valve (504) through a pipeline, and a cathode tail gas cut-off valve (503) is connected with the cathode tail gas backpressure valve (504) in parallel; the anode cavity liquid outlet (529) is connected to a condensed water outlet (507) through an anode tail gas liquid outlet valve (508) through a pipeline; and the cathode cavity liquid outlet (530) is connected to a condensed water outlet (507) through a cathode tail gas liquid outlet valve (509) by a pipeline.

2. The fuel cell system with bipolar exhaust gas pressure linkage balancing function according to claim 1, characterized in that the auxiliary control system (600) comprises a data collector (601), a controller (602), a load (603) and other control components (604); the data acquisition unit (601) is used for acquiring a voltage-saving detection signal of the galvanic pile module (100) and transmitting the voltage-saving detection signal to the controller (602); the controller (602) realizes data acquisition, interaction, operation, analysis or processing of pressure, temperature and flow signals under various instructions, and controls the operation processes of starting, running, stopping and the like of the fuel cell system and the backpressure regulation process; a load (603) for converting electrical energy generated by the fuel cell system into another form of energy; other control components (604) comprise a module power supply, a transformer, a contactor, a signal conversion module, a communication conversion module, a safety protection component and the like, and are used as auxiliary accessories of the control system.

3. The fuel cell system with the bipolar tail gas pressure linkage balancing function according to claim 2, wherein the back pressure adjusting process includes three modes of anode tail gas back pressure adjustment, cathode tail gas back pressure adjustment or anode tail gas back pressure and cathode tail gas back pressure adjustment; taking the back pressure regulation of the anode tail gas as an example, the back pressure regulation process specifically comprises the following steps:

when receiving an anode tail gas backpressure regulation instruction, the controller (602) compares a currently collected anode pressure detection value Psn with a preset anode pressure target value Psn, and when the anode pressure target value Psn is higher than the anode pressure detection value Psn, the opening degree of the anode tail gas backpressure valve (502) is reduced, otherwise, the opening degree of the anode tail gas backpressure valve (502) is increased; further comparing the anode pressure target value Psn with the anode pressure detection value Psn, when the anode pressure target value Psn is lower than or equal to the anode pressure detection value Psn, maintaining the opening of the anode tail gas backpressure valve (502), otherwise, reducing the opening of the anode tail gas backpressure valve (502); further judging whether a shutdown instruction is received, finishing the anode tail gas backpressure regulating process when the shutdown instruction is received, and otherwise, continuously comparing the anode pressure target value Psn with the anode pressure detection value Psn;

the anode pressure detection value Psn is an arithmetic average value of an anode stack entering pressure detection value Ps1, an anode stack outlet pressure detection value Ps5 or an anode stack entering pressure detection value Ps1 and an anode stack outlet pressure detection value Ps5, and the anode pressure target value Psn is an arithmetic average value of an anode stack entering pressure value Ps1, an anode stack outlet pressure value Ps5 or an anode stack entering pressure value Ps1 and an anode stack outlet pressure value Ps5 corresponding to the optimal working state of the galvanic pile module (100);

the back pressure adjusting process of the cathode tail gas is the same as the back pressure adjusting process of the anode tail gas.

4. The fuel cell system having a bipolar exhaust gas pressure-balanced function according to any one of claims 1 to 3, wherein the operating state control method of the anode exhaust gas cutoff valve (501) and the anode exhaust gas back pressure valve (502) is as follows: when the fuel cell system regulates the anode tail gas back pressure, the anode tail gas back pressure valve (502) works, and the anode tail gas stop valve (501) is closed; when the fuel cell system does not adjust the anode tail gas back pressure, the anode tail gas cut-off valve (501) works, and the anode tail gas back pressure valve (502) is closed; when the fuel cell system is in an emergency exhaust state, both the anode off-gas back-pressure valve (502) and the anode off-gas shut-off valve (501) are in an open state.

5. The fuel cell system having a bipolar exhaust gas pressure-balanced function according to any one of claims 1 to 3, wherein the operating state control method of the cathode exhaust gas cutoff valve (503) and the cathode exhaust gas backpressure valve (504) is as follows: when the fuel cell system regulates the back pressure of the cathode tail gas, the back pressure valve (504) of the cathode tail gas works, and the cut-off valve (503) of the cathode tail gas is closed; when the fuel cell system does not adjust the back pressure of the cathode tail gas, the cathode tail gas cut-off valve (503) works, and the cathode tail gas back pressure valve (504) is closed; when the fuel cell system is in an emergency exhaust state, both the cathode off-gas backpressure valve (504) and the cathode off-gas shutoff valve (503) are in an open state.

6. The fuel cell system with the bipolar exhaust gas pressure linkage balancing function according to any one of claims 1 to 3, wherein the anode stack outlet pressure Pe2 is equal to the sum of a pressure drop Δ Pe3 flowing through the stack anode exhaust gas discharge pipe (71) and a pressure drop Δ Pe2 flowing through the anode exhaust gas cavity (523), a pressure drop Δ Pe1 flowing through the anode exhaust gas outlet (526) to the system anode exhaust gas outlet (505), and an atmospheric pressure Pe1 received by the system anode exhaust gas outlet (505), namely: pe2 ═ Δ Pe3+ Δ Pe2+ Δ Pe1+ Pe 1;

the cathode stack-out pressure Pe4 is equal to the sum of the pressure drop Δ Pe6 flowing through the stack cathode tail gas discharge pipe (72) and the pressure drop Δ Pe5 flowing through the cathode tail gas cavity (524), the pressure drop Δ Pe4 flowing through the cathode tail gas outlet (528) to the system cathode tail gas exhaust outlet (506), and the atmospheric pressure Pe3 to which the system cathode tail gas exhaust outlet (506) is exposed, namely: pe4 ═ Δ Pe6+ Δ Pe5+ Δ Pe4+ Pe 3;

the length of the stack anode tail gas discharge pipe (71) and the length of the stack cathode tail gas discharge pipe (72) are short, and the corresponding pressure drop delta Pe3 and the corresponding pressure drop delta Pe6 are ignored; the atmospheric pressure Pe1 and the atmospheric pressure Pe3 are approximately equal in value;

furthermore, when the numerical difference between the anode stack-out pressure Pe2 and the cathode stack-out pressure Pe4 is large, the numerical difference between the pressure drop delta Pe1 and the pressure drop delta Pe4 is large, and when delta Pe1 is more than delta Pe4, the elastic diaphragm (521) expands towards the cathode tail gas cavity (524), so that the volume of the cathode tail gas cavity (524) is reduced, the pressure drop delta Pe5 is increased, the difference between the delta Pe1 and the delta Pe4 is balanced, and the cathode and anode stack-out pressure balance is further ensured; when the delta Pe1 is less than the delta Pe4, the elastic diaphragm (521) expands towards the anode tail gas cavity (523), so that the volume of the anode tail gas cavity (523) is reduced, and the pressure drop delta Pe2 is increased to balance the difference between the delta Pe1 and the delta Pe4, thereby ensuring the pile-forming pressure balance of the cathode and the anode.

7. The fuel cell system with bipolar exhaust gas pressure linkage balancing function according to any one of claims 1 to 3, wherein the elastic membrane (521) comprises rubber, polytetrafluoroethylene, ethylene propylene diene monomer or fluororubber.

8. The fuel cell system with bipolar exhaust gas pressure linkage balancing function according to any one of claims 1 to 3, wherein the housing (520) is square, cylindrical or butterfly.

Technical Field

The invention belongs to the technical field of fuel cells, and particularly relates to a fuel cell system with a bipolar tail gas pressure linkage balancing function.

Background

The fuel cell has the characteristics of high energy conversion efficiency, low working temperature, low noise, zero pollution and the like, and has a tendency of explosive development in recent years. The fuel cell is an electrochemical reaction device which directly converts chemical energy into electric energy through electrochemical reaction of hydrogen and oxygen, generally comprises a fuel cell stack, a gas transmission and monitoring system, a tail gas system, a heat dissipation system, a control system, a hydrogen safety system, an auxiliary power supply and an electric energy output system, and can be used in the scenes of vehicles, aerospace, fixed power stations, underwater devices and the like.

In recent years, key materials of fuel cells have great breakthrough, so that the performance of fuel cell stacks is improved quickly, and the power density and the service life of the stacks are continuously new and high. However, many system integrators have found that the performance and life of the stack is greatly compromised when the stack is integrated into a fuel cell system, one of the most important reasons being stack performance consistency and flow field drainage problems caused directly or indirectly by stack pressure management problems. In order to reduce the proton conduction resistance and the water diffusion performance, the thickness of a proton exchange membrane serving as a core material of a galvanic pile is thinner and thinner, so that an obvious effect is brought to the performance improvement of the galvanic pile to a certain extent, but the thickness reduction of the proton exchange membrane also brings a great problem to the pressure management of the cathode and the anode of the galvanic pile, and the pressure difference between two sides of the membrane is generally required to be not more than 35 kPa. Particularly, when the galvanic pile develops towards the direction of high power density, the drainage performance and the back pressure capability of the galvanic pile are required to be good, so that the problems of the single-side flow field pressure difference of the cathode and the anode of the galvanic pile, the membrane pressure difference of the double sides of the cathode and the anode of the galvanic pile and the back pressure of the galvanic pile are interwoven into a whole. When the differential pressure of the single-side flow field of the cathode and the anode of the galvanic pile is low, the operation window of the differential pressure of the two sides of the cathode and the anode membrane is widened, and the control difficulty of the differential pressure of the two sides of the membrane is reduced, but the drainage performance of the flow field is poor when the differential pressure of the single-side flow field of the cathode and the anode is low, and local flooding is easily caused; when the differential pressure of a flow field on one side of the cathode and the anode of the galvanic pile is higher, the drainage capability of the flow fields on two sides of the cathode and the anode of the galvanic pile can be greatly enhanced, but the operation window of the differential pressure on two sides of the cathode and the anode membranes is narrowed, and the difficulty in managing the whole pressure of the galvanic pile is increased.

The influence of the whole pressure management problem of the galvanic pile on different operation conditions is different, and the influence is mainly summarized into two aspects: on one hand, the cathode and anode pressure management of the fuel cell system in the steady-state operation and loading and unloading processes is not in place, and unipolar or bipolar pressure fluctuation occurs, so that the internal reaction of the electric pile is unbalanced, and the problems of electric pile performance reduction, local water logging or local drying and the like are easily caused; on the other hand, in the emergency state of the system, the emergency capacity of the system on pressure management cannot keep up, so that the cathode and anode pressure of the system is excessively high instantaneously, membrane materials are damaged, and the service life of a fuel cell is shortened.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a fuel cell system with a bipolar tail gas pressure linkage balancing function, anode tail gas and cathode tail gas in the operation process of a fuel cell change the tail gas flow resistance through a bipolar pressure linkage device, so that the pressure of the cathode and anode tail gas of a stack outlet can be correlated under various system operation states, the stack outlet pressure keeps mutual balance, the pressure coping capability of the system under the conditions of steady-state working condition, dynamic load and unload power, fault condition, emergency shutdown and the like is enhanced, and the pressure operation range of the fuel cell system is greatly widened.

The specific technical scheme of the invention is as follows:

a fuel cell system with bipolar tail gas pressure linkage balance function comprises a stack module 100, and a hydrogen subsystem 200, an air subsystem 300, a heat management subsystem 400, a tail gas subsystem 500 and an auxiliary control system 600 which are connected with the stack module 100, and is characterized in that the tail gas subsystem 500 comprises a bipolar tail gas pressure linkage balance device 5, an anode tail gas cut-off valve 501, an anode tail gas back-pressure valve 502, a cathode tail gas cut-off valve 503, a cathode tail gas back-pressure valve 504, an anode tail gas drain valve 508, a cathode tail gas drain valve 509, a system anode tail gas drain outlet 505, a system cathode tail gas drain outlet 506, a condensed water drain outlet 507 and pipelines for connection;

the bipolar tail gas pressure linkage balancing device 5 comprises a shell 520, an elastic diaphragm 521, a diaphragm fixing member 522, an anode tail gas cavity 523, a cathode tail gas cavity 524, an anode tail gas inlet 525, an anode tail gas outlet 526, a cathode tail gas inlet 527, a cathode tail gas outlet 528, an anode cavity liquid outlet 529 and a cathode cavity liquid outlet 530;

the elastic diaphragm 521 is fixed by a diaphragm fixing member 522, and divides the inside of the casing 520 into an anode tail gas cavity 523 and a cathode tail gas cavity 524; the anode tail gas inlet 525 and the cathode tail gas inlet 527 are respectively connected with the stack anode tail gas discharge pipe 71 and the stack cathode tail gas discharge pipe 72; the anode tail gas outlet 526 is connected to the system anode tail gas outlet 505 through an anode tail gas backpressure valve 502 by a pipeline, and the anode tail gas stop valve 501 is connected with the anode tail gas backpressure valve 502 in parallel; the cathode tail gas outlet 528 is connected to the system cathode tail gas outlet 506 through the cathode tail gas backpressure valve 504 by a pipeline, and the cathode tail gas cut-off valve 503 is connected with the cathode tail gas backpressure valve 504 in parallel; the anode cavity liquid outlet 529 is connected to a condensed water outlet 507 through an anode tail gas liquid outlet valve 508 through a pipeline; the cathode chamber drain port 530 is connected to a condensate drain port 507 via a cathode exhaust drain valve 509 via a pipe.

Further, the elastic diaphragm 521 has strong elastic deformation capability, high compactness and good isolation to hydrogen molecules, and comprises rubber, polytetrafluoroethylene, ethylene propylene diene monomer or fluororubber and the like.

Further, the housing 520 may be square, cylindrical, butterfly, or any other shape.

Further, the auxiliary control system 600 includes a data collector 601, a controller 602, a load 603, and other control components 604; the data acquisition unit 601 is used for acquiring the voltage-saving detection signal of the stack module 100 and transmitting the voltage-saving detection signal to the controller 602; the controller 602, under various instructions, realizes data acquisition, interaction, operation, analysis or processing of pressure, temperature and flow signals, and controls the operation processes of starting, running, stopping and the like of the fuel cell system and the backpressure regulation process; the load 603 is used to convert the electrical energy generated by the fuel cell system into another form of energy; the other control components 604 include a module power supply, a transformer, a contactor, a signal conversion module, a communication conversion module, a safety protection component and the like, and are used as auxiliary accessories of the control system.

Further, the backpressure regulating process comprises three modes of anode tail gas backpressure regulation, cathode tail gas backpressure regulation or joint regulation of the anode tail gas backpressure and the cathode tail gas backpressure, and balance of the pile outlet pressure of the cathode and the anode can be realized;

taking the back pressure regulation of the anode tail gas as an example, the back pressure regulation process specifically comprises the following steps:

when receiving an anode tail gas backpressure regulation instruction, the controller 602 compares a currently acquired anode pressure detection value Psn with a preset anode pressure target value Psn, and when the anode pressure target value Psn is higher than the anode pressure detection value Psn, reduces the opening degree of the anode tail gas backpressure valve 502, otherwise increases the opening degree of the anode tail gas backpressure valve 502; further comparing the anode pressure target value Psn with the anode pressure detection value Psn, when the anode pressure target value Psn is lower than or equal to the anode pressure detection value Psn, maintaining the opening of the anode tail gas backpressure valve 502, otherwise, reducing the opening of the anode tail gas backpressure valve 502; further judging whether a shutdown instruction is received, finishing the anode tail gas backpressure regulating process when the shutdown instruction is received, and otherwise, continuously comparing the anode pressure target value Psn with the anode pressure detection value Psn;

the anode pressure detection value Psn is an arithmetic average value of an anode stack entering pressure detection value Ps1, an anode stack outlet pressure detection value Ps5 or an anode stack entering pressure detection value Ps1 and an anode stack outlet pressure detection value Ps5, and the anode pressure target value Psn is an arithmetic average value of an anode stack entering pressure value Ps1, an anode stack outlet pressure value Ps5 or an anode stack entering pressure value Ps1 and an anode stack outlet pressure value Ps5 corresponding to the optimal working state of the galvanic pile module 100;

the back pressure adjusting process of the cathode tail gas is the same as the back pressure adjusting process of the anode tail gas.

Further, the working state control method of the anode off-gas cut-off valve 501 and the anode off-gas backpressure valve 502 is as follows: when the fuel cell system adjusts the anode tail gas back pressure, the anode tail gas back pressure valve 502 works, and the anode tail gas cut-off valve 501 is closed; when the fuel cell system does not adjust the anode tail gas back pressure, the anode tail gas cut-off valve 501 works, and the anode tail gas back pressure valve 502 is closed; when the fuel cell system is in the emergency exhaust state, both the anode off-gas back-pressure valve 502 and the anode off-gas cutoff valve 501 are in the open state.

Further, the method for controlling the operating states of the cathode off-gas cut-off valve 503 and the cathode off-gas back-pressure valve 504 is as follows: when the fuel cell system performs the adjustment of the back pressure of the cathode tail gas, the back pressure valve 504 of the cathode tail gas works, and the cut-off valve 503 of the cathode tail gas is closed; when the fuel cell system does not adjust the cathode tail gas back pressure, the cathode tail gas cut-off valve 503 works, and the cathode tail gas back pressure valve 504 is closed; when the fuel cell system is in the emergency exhaust state, both the cathode off-gas back-pressure valve 504 and the cathode off-gas cutoff valve 503 are in the open state.

Further, the anode stack-out pressure Pe2 is equal to the sum of the pressure drop Δ Pe3 flowing through the stack anode tail gas discharge pipe 71 and the pressure drop Δ Pe2 flowing through the anode tail gas cavity 523, the pressure drop Δ Pe1 flowing through the anode tail gas outlet 526 to the system anode tail gas discharge port 505, and the atmospheric pressure Pe1 received by the system anode tail gas discharge port 505, that is: pe2 ═ Δ Pe3+ Δ Pe2+ Δ Pe1+ Pe 1;

the cathode stack-out pressure Pe4 is equal to the sum of the pressure drop Δ Pe6 flowing through the stack cathode tail gas exhaust pipe 72 and the pressure drop Δ Pe5 flowing through the cathode tail gas cavity 524, the pressure drop Δ Pe4 flowing through the cathode tail gas outlet 528 to the system cathode tail gas exhaust port 506, and the atmospheric pressure Pe3 experienced by the system cathode tail gas exhaust port 506, namely: pe4 ═ Δ Pe6+ Δ Pe5+ Δ Pe4+ Pe 3;

the lengths of the stack anode tail gas discharge pipe 71 and the stack cathode tail gas discharge pipe 72 are short, and the corresponding pressure drop delta Pe3 and pressure drop delta Pe6 can be ignored; the atmospheric pressure Pe1 and the atmospheric pressure Pe3 are approximately equal in value;

furthermore, when the numerical difference between the anode stack-out pressure Pe2 and the cathode stack-out pressure Pe4 is large, the numerical difference between the pressure drop Δ Pe1 and the pressure drop Δ Pe4 is large, and when Δ Pe1 is greater than Δ Pe4, the elastic diaphragm 521 expands towards the cathode tail gas cavity 524, so that the volume of the cathode tail gas cavity 524 is reduced, the pressure drop Δ Pe5 is increased, the difference between Δ Pe1 and Δ Pe4 is balanced, and the cathode and anode stack-out pressure balance is further ensured; when the delta Pe1 is less than the delta Pe4, the elastic diaphragm 521 expands towards the anode tail gas cavity 523, so that the volume of the anode tail gas cavity 523 is reduced, and the pressure drop delta Pe2 is increased to balance the difference between the delta Pe1 and the delta Pe4, thereby ensuring the pile-forming pressure balance of the cathode and the anode.

The invention has the beneficial effects that:

1. the invention provides a fuel cell system with a bipolar tail gas pressure linkage balancing function, which is characterized in that a tail gas subsystem is provided with a bipolar tail gas pressure linkage balancing device to physically isolate anode tail gas and cathode tail gas, and has the pressure linkage balancing function, so that the requirement of pile cathode and anode pressure management is met, the pressure stability of the fuel cell system in a full power range is improved, and the tolerance of the pile cathode and anode pressure management system to the pile cathode and anode single-pole flow resistance range is enhanced;

2. in order to respond to the dynamic change of the power consumption of the load, the supply amount of hydrogen at the anode side and air at the cathode side of the fuel cell needs to be changed continuously along with the load change rate, and when the change rate is higher, the differential pressure at the two sides of the cathode and the anode can fluctuate unstably;

3. the invention also provides a buffering and balancing space for the cathode and anode tail gas emission difference suddenly increased in the emergency shutdown process, avoids the problem of cathode and anode pressure unbalance of the galvanic pile in the emergency shutdown process, improves the stability of cathode and anode differential pressure in the emergency shutdown process, and enhances the emergency capacity of differential pressure management of a system in a fault state.

Drawings

Fig. 1 is a schematic structural diagram of a bipolar tail gas pressure linkage balancing device according to embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of a fuel cell system having a bipolar tail gas pressure linkage balancing function according to embodiment 1 of the present invention;

FIG. 3 is a schematic diagram of the bipolar pressure linkage balancing process according to embodiment 1 of the present invention;

FIG. 4 is a back pressure regulation control method according to embodiment 1 of the present invention;

the reference numbers are as follows:

100: a stack module; 200: a hydrogen subsystem; 300: an air subsystem; 400: a thermal management subsystem; 500: an exhaust subsystem; 600: an auxiliary control system; 5: a bipolar tail gas pressure linkage balancing device; 501: an anode tail gas cut-off valve; 502: an anode tail gas back pressure valve; 503: a cathode tail gas cut-off valve; 504: a cathode tail gas back pressure valve; 505: a system anode tail gas outlet; 506: a system cathode tail gas outlet; 507: a condensed water discharge port; 508: an anode tail gas drain valve; 509: a cathode tail gas drain valve; 520: a housing; 521: an elastic diaphragm; 522: a diaphragm mount; 523: an anode tail gas cavity; 524: a cathode tail gas cavity; 525: an anode tail gas inlet; 526: an anode tail gas outlet; 527: a cathode tail gas inlet; 528: a cathode tail gas outlet; 529: an anode cavity drain port; 530: a cathode cavity drain port; 1: a fuel cell stack; 121: a hydrogen stack inlet temperature sensor; 122: a hydrogen stack inlet pressure sensor; 123: a hydrogen stack outlet temperature sensor; 124: a hydrogen stack-out pressure sensor; 125: an air inlet temperature sensor; 126: an air in-pile pressure sensor; 127: an air stack-out temperature sensor; 128: an air stack pressure sensor; 129: a temperature sensor for the cooling liquid entering the reactor; 130: the cooling liquid enters the pile pressure sensor; 131: a coolant out-of-stack temperature sensor; 132: a coolant discharge pressure sensor; 201: a high pressure hydrogen storage cylinder set; 202: an air source pressure sensor; 203: a primary pressure reducing valve; 204: a secondary pressure reducing valve; 205: a safety valve; 206: a hydrogen inlet pile front switch valve; 207: a hydrogen pre-stack flow meter; 301: an air compressor; 302: an air source pressure sensor; 303: a pressure reducing valve; 304: a safety valve; 305: an air inlet pile front switch valve; 306: an air pre-stack flow meter; 401: an expansion tank; 402: a heat exchanger; 403: a flow meter; 404: a coolant pump; 405: a refrigerant inlet; 406: a refrigerant outlet; 601: a data acquisition unit; 602: a controller; 603: a load; 604: other control components; 71: a pile anode tail gas discharge pipe; 72: a stack cathode tail gas discharge pipe; 73: a pipeline from the anode tail gas outlet 526 to the system anode tail gas outlet 505; 74: a cathode tail gas outlet 528 to the system cathode tail gas exhaust outlet 506.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the following embodiments and the accompanying drawings.

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

Example 1

The present embodiment provides a fuel cell system with bipolar tail gas pressure linkage balancing function, which is configured as shown in fig. 2 and includes a stack module 100, and a hydrogen subsystem 200, an air subsystem 300, a thermal management subsystem 400, a tail gas subsystem 500 and an auxiliary control system 600 connected to the stack module 100.

The stack module 100 comprises a fuel cell stack 1, a hydrogen inlet stack temperature sensor 121 and a hydrogen inlet stack pressure sensor 122 at a hydrogen inlet stack port of the stack, a hydrogen outlet stack temperature sensor 123 and a hydrogen outlet stack pressure sensor 124 at a cathode tail gas outlet stack port of the stack, an air inlet stack temperature sensor 125 and an air inlet stack pressure sensor 126 at an air inlet stack port of the stack, an air outlet stack temperature sensor 127 and an air outlet stack pressure sensor 128 at a cathode tail gas outlet stack port of the stack, a cooling liquid inlet stack temperature sensor 129 and a cooling liquid inlet stack pressure sensor 130 at a cooling liquid inlet stack port of the stack, and a cooling liquid outlet stack temperature sensor 131 and a cooling liquid outlet stack pressure sensor 132 at a cooling liquid outlet stack; the temperature and pressure sensors at each position are used to detect the temperature and pressure at the corresponding position in real time, and feed back the detection signals to the controller 602.

The hydrogen subsystem 200 comprises a high-pressure hydrogen storage cylinder group 201, an air source pressure sensor 202, a primary pressure reducing valve 203, a secondary pressure reducing valve 204, a safety valve 205, a hydrogen pile-entering front switch valve 206, a hydrogen pile-entering front flowmeter 207, a pipeline and a pipeline connecting piece which are connected in sequence; wherein, the primary pressure reducing valve 203 is used for reducing the pressure of the high-pressure hydrogen (generally 70MPa or 35MPa) from the high-pressure hydrogen storage cylinder group 201 to the medium pressure (generally 5-8MPa), and the medium pressure hydrogen is reduced to the required pressure (generally lower than 0.6MPa) at the inlet end of the fuel cell through the secondary pressure reducing valve 204; the safety valve 205 is used for relieving pressure of a relevant part connected with the safety valve when an abnormal condition occurs so as to protect relevant components of the fuel cell system from pressure impact; the hydrogen inlet front switch valve 206 is used for cutting off or conducting the inlet hydrogen; the hydrogen flow meter 207 is used for detecting the flow of the hydrogen entering the reactor and feeding back a flow detection signal to the controller 602 for processing. The hydrogen flow path in the operation process of the fuel cell system is as follows: the high-pressure hydrogen from the high-pressure hydrogen storage cylinder group 201 is sequentially decompressed to the appropriate pressure of the fuel cell by the primary decompression valve 203 and the secondary decompression valve 204, and then sequentially passes through the safety valve 205, the hydrogen pile-entering front switch valve 206 and the hydrogen pile-entering front flowmeter 207 and then enters the pile hydrogen pile inlet of the fuel cell pile 1 in the pile module 100.

The air subsystem 300 comprises an air compressor 301, an air source pressure sensor 302, a pressure reducing valve 303, a safety valve 304, an air pile-entering front switch valve 305, an air pile-entering front flow meter 306, and pipelines and pipeline connectors which are connected in sequence; wherein the pressure reducing valve 303 is used to reduce the pressure of the compressed air from the air compressor 301 to the required pressure at the inlet end of the fuel cell (typically below 0.6 MPa); the safety valve 304 is used for relieving pressure of a relevant part connected with the safety valve when an abnormal condition occurs so as to protect relevant components of the fuel cell system from pressure impact; the air inlet-to-pile switching valve 305 is used for cutting off or conducting inlet air; the pre-stack air flow meter 306 is used for detecting the flow rate of stack air and feeding back a flow rate detection signal to the controller 602 for processing. The air circulation path in the operation process of the fuel cell system is as follows: the compressed air from the air compressor 301 flows through a pressure reducing valve 303, a safety valve 304, an air pre-stack switching valve 305, an air pre-stack flow meter 306, and then enters the stack air inlet of the fuel cell stack 1 in the stack module 100.

The heat management subsystem 400 comprises a refrigerant inlet 405, a refrigerant outlet 406, an expansion water tank 401, a heat exchanger 402, a flowmeter 403 and a coolant pump 404 which are sequentially connected; the expansion water tank 401 is used for supplying cooling liquid to the cooling liquid loop or balancing volume change of the cooling circulation loop caused by temperature or pressure; the heat exchanger 402 is used for transferring heat generated by the fuel cell stack 1, wherein a cooling liquid flows through the hot side of the heat exchanger, a refrigerant medium flows through the cold side of the heat exchanger, and the refrigerant medium is supplied from the outside of the system; the flow meter 403 is used for detecting the flow rate of the cooling liquid and feeding back a flow signal to the controller 602; the coolant pump 404 is configured to provide a head pressure to the coolant to overcome the resistance of the components of the coolant circuit and to facilitate flow through the coolant circuit. The cooling liquid circulation path in the operation process of the fuel cell system is as follows: cooling liquid from a fuel cell stack 1 in the stack module 100 sequentially passes through a heat exchanger 402, a flow meter 403 and a cooling liquid pump 404, then returns to the fuel cell stack 1, and enters a stack cooling liquid inlet pipeline for continuous circulation; in the process, the refrigerant medium flows in from the refrigerant inlet 405, takes heat of the cooling liquid through the cold side of the heat exchanger 402, and then flows out from the refrigerant outlet 406.

The tail gas subsystem 500 comprises a bipolar tail gas pressure linkage balancing device 5, an anode tail gas cut-off valve 501, an anode tail gas backpressure valve 502, a cathode tail gas cut-off valve 503, a cathode tail gas backpressure valve 504, an anode tail gas drain valve 508, a cathode tail gas drain valve 509, a system anode tail gas discharge port 505, a system cathode tail gas discharge port 506, a condensed water discharge port 507 and a pipeline for connection; as shown in fig. 1, the bipolar tail gas pressure linkage balancing device 5 includes a housing 520, an elastic diaphragm 521, a diaphragm fixing member 522, an anode tail gas cavity 523, a cathode tail gas cavity 524, an anode tail gas inlet 525, an anode tail gas outlet 526, a cathode tail gas inlet 527, a cathode tail gas outlet 528, an anode cavity drain 529, and a cathode cavity drain 530; the elastic diaphragm 521 is made of rubber and is fixed by a diaphragm fixing piece 522, so that the inside of the square shell 520 is divided into an anode tail gas cavity 523 and a cathode tail gas cavity 524; the anode tail gas inlet 525 and the cathode tail gas inlet 527 are respectively connected with the stack anode tail gas discharge pipe 71 and the stack cathode tail gas discharge pipe 72; the anode tail gas outlet 526 is connected to the system anode tail gas outlet 505 through an anode tail gas backpressure valve 502 by a pipeline, and the anode tail gas stop valve 501 is connected with the anode tail gas backpressure valve 502 in parallel; the cathode tail gas outlet 528 is connected to the system cathode tail gas outlet 506 through the cathode tail gas backpressure valve 504 by a pipeline, and the cathode tail gas cut-off valve 503 is connected with the cathode tail gas backpressure valve 504 in parallel; the anode cavity liquid outlet 529 is connected to a condensed water outlet 507 through an anode tail gas liquid outlet valve 508 through a pipeline; the cathode chamber drain port 530 is connected to a condensate drain port 507 via a cathode exhaust drain valve 509 via a pipe. The tail gas circulation path in the operation process of the fuel cell system is as follows: anode tail gas from a fuel cell stack 1 in the stack module 100 enters a tail gas subsystem 500, enters an anode tail gas cavity 523 through an anode tail gas inlet 525 of a bipolar tail gas pressure linkage balancing device 5, flows out of an anode tail gas outlet 526 after pressure balancing, is divided into two branches through a pipeline, respectively passes through an anode tail gas backpressure valve 502 and an anode tail gas stop valve 501, and then flows to a system anode tail gas outlet 505; cathode tail gas from a fuel cell stack 1 in the stack module 100 enters a tail gas subsystem 500, enters a cathode tail gas cavity 524 through a cathode tail gas inlet 527 of a bipolar tail gas pressure linkage balancing device 5, flows out of a cathode tail gas outlet 528 after pressure balancing, is divided into two branches through a pipeline, respectively passes through a cathode tail gas backpressure valve 504 and a cathode tail gas cut-off valve 503, and then flows to a system cathode tail gas outlet 506; the anode tail gas of the anode tail gas cavity 523 and the cathode tail gas of the cathode tail gas cavity 524 in the bipolar tail gas pressure linkage balancing device 5 are balanced, and gas-liquid separation is completed; the condensed water from the anode tail gas cavity 523 flows out through the anode cavity drain 529 and flows to the condensed water outlet 507 through the anode tail gas drain valve 508; the condensed water from the cathode off-gas chamber 524 flows out through the cathode chamber drain port 530, passes through the cathode off-gas drain valve 509, and flows to the condensed water drain port 507.

The auxiliary control system 600 comprises a data collector 601, a controller 602, a load 603 and other control components 604; the data acquisition unit 601 is used for acquiring the voltage-saving detection signal of the stack module 100 and transmitting the voltage-saving detection signal to the controller 602; the controller 602, under various instructions, realizes data acquisition, interaction, operation, analysis or processing of pressure, temperature and flow signals, and controls the operation processes of starting, running, stopping and the like of the fuel cell system and the backpressure regulation process; the load 603 is used to convert the electrical energy generated by the fuel cell system into another form of energy; the other control components 604 include a module power supply, a transformer, a contactor, a signal conversion module, a communication conversion module, a safety protection component and the like, and are used as auxiliary accessories of the control system.

The back pressure adjusting process comprises three modes of anode tail gas back pressure adjustment, cathode tail gas back pressure adjustment or common adjustment of the anode tail gas back pressure and the cathode tail gas back pressure, and the balance of the pile-forming pressure of the cathode and the anode can be realized;

taking the anode tail gas back pressure regulation as an example, as shown in fig. 4, the back pressure regulation process specifically includes:

when receiving an anode tail gas backpressure regulation instruction, the controller 602 compares a currently acquired anode pressure detection value Psn with a preset anode pressure target value Psn, and when the anode pressure target value Psn is higher than the anode pressure detection value Psn, reduces the opening degree of the anode tail gas backpressure valve 502, otherwise increases the opening degree of the anode tail gas backpressure valve 502; further comparing the anode pressure target value Psn with the anode pressure detection value Psn, when the anode pressure target value Psn is lower than or equal to the anode pressure detection value Psn, maintaining the opening of the anode tail gas backpressure valve 502, otherwise, reducing the opening of the anode tail gas backpressure valve 502; and further judging whether a shutdown instruction is received, finishing the anode tail gas backpressure regulating process when the shutdown instruction is received, and otherwise, continuously comparing the anode pressure target value Psn with the anode pressure detection value Psn. The anode pressure detection value Psn is an arithmetic average of an anode stack entering pressure detection value Ps1 measured by the hydrogen stack entering pressure sensor 122, an anode stack outlet pressure detection value Ps5 measured by the hydrogen stack outlet pressure sensor 124 or an anode stack entering pressure detection value Ps1 and an anode stack outlet pressure detection value Ps5, and the anode pressure target value Psn is an arithmetic average of an anode stack entering pressure value Ps1, an anode stack outlet pressure value Ps5 or an anode stack entering pressure value Ps1 and an anode stack outlet pressure value Ps5 corresponding to the optimal working state of the stack module 100; the back pressure adjusting process of the cathode tail gas is the same as the back pressure adjusting process of the anode tail gas. Although the process only appears to adjust the anode tail gas back pressure, the bipolar pressure linkage balancing device 5 actually links the cathode and anode stack pressure together, so that the aim of increasing or decreasing the bipolar back pressure is achieved.

Further, the working state control method of the anode off-gas cut-off valve 501 and the anode off-gas backpressure valve 502 is as follows: when the fuel cell system adjusts the anode tail gas back pressure, the anode tail gas back pressure valve 502 works, and the anode tail gas cut-off valve 501 is closed; when the fuel cell system does not adjust the anode tail gas back pressure, the anode tail gas cut-off valve 501 works, and the anode tail gas back pressure valve 502 is closed; when the fuel cell system is in the emergency exhaust state, both the anode off-gas back-pressure valve 502 and the anode off-gas cutoff valve 501 are in the open state.

Further, the method for controlling the operating states of the cathode off-gas cut-off valve 503 and the cathode off-gas back-pressure valve 504 is as follows: when the fuel cell system performs the adjustment of the back pressure of the cathode tail gas, the back pressure valve 504 of the cathode tail gas works, and the cut-off valve 503 of the cathode tail gas is closed; when the fuel cell system does not adjust the cathode tail gas back pressure, the cathode tail gas cut-off valve 503 works, and the cathode tail gas back pressure valve 504 is closed; when the fuel cell system is in the emergency exhaust state, both the cathode off-gas back-pressure valve 504 and the cathode off-gas cutoff valve 503 are in the open state.

As shown in fig. 3, the working principle of the bipolar tail gas pressure linkage balancing device 5 in this embodiment to realize the cathode and anode stack-out pressure balance specifically includes:

the anode stack-out pressure Pe2 is equal to the sum of the pressure drop Δ Pe3 flowing through the stack anode tail gas discharge pipe 71 and the pressure drop Δ Pe2 flowing through the anode tail gas cavity 523, the pressure drop Δ Pe1 flowing through the anode tail gas outlet 526 to the pipe 73 of the system anode tail gas discharge port 505, and the atmospheric pressure Pe1 received by the system anode tail gas discharge port 505, that is: pe2 ═ Δ Pe3+ Δ Pe2+ Δ Pe1+ Pe 1;

the cathode stack-out pressure Pe4 is equal to the sum of the pressure drop Δ Pe6 flowing through the stack cathode tail gas exhaust pipe 72 and the pressure drop Δ Pe5 flowing through the cathode tail gas cavity 524, the pressure drop Δ Pe4 flowing through the cathode tail gas outlet 528 to the pipeline 74 of the system cathode tail gas exhaust port 506, and the atmospheric pressure Pe3 received by the system cathode tail gas exhaust port 506, namely: pe4 ═ Δ Pe6+ Δ Pe5+ Δ Pe4+ Pe 3;

in order to ensure that the pressure balance effect of the pressure passing through the bipolar tail gas pressure linkage balance device 5 is good, the lengths of the pile anode tail gas discharge pipe 71 and the pile cathode tail gas discharge pipe 72 are short, and the corresponding pressure drop delta Pe3 and the corresponding pressure drop delta Pe6 can be ignored; the atmospheric pressure Pe1 and the atmospheric pressure Pe3 are approximately equal in value;

the following three cases can be classified according to the operation requirements of the fuel cell system:

the first condition is as follows: wide power range operating pressure adaptation process for fuel cell systems

When the fuel cell system operates at low power, the hydrogen flow and the air flow required by the fuel cell stack 1 are relatively small, the anode tail gas and the cathode tail gas flow are also relatively small, the pressure drop formed by the anode tail gas and the cathode tail gas at each part of the stack after the stack is discharged is relatively small, the deformation amount of the elastic diaphragm 521 in the bipolar pressure linkage balancing device 5 is relatively small, and the cathode and anode stack discharge tail gas pressure can be kept similar; when the fuel cell system is gradually loaded to high power, the hydrogen flow and the air flow required by the fuel cell stack 1 are gradually increased, the flows of anode tail gas and cathode tail gas are also gradually increased, the pressure drop formed by the anode tail gas and the cathode tail gas at each part of the stack is gradually increased, the pressure drop difference formed by the tail 73 pipeline and the tail 74 pipeline is gradually increased, and at the moment, the deformation amount of the elastic diaphragm 521 is gradually increased so as to keep the pressure of the cathode and anode stack outlet tail gas close; the greater the difference in the flow rate of the off-gas between the cathode and anode of the fuel cell system, the greater the amount of deformation of the elastic diaphragm 521. When the numerical difference between the anode stack-out pressure Pe2 and the cathode stack-out pressure Pe4 is large, the numerical difference between the pressure drop Δ Pe1 and the pressure drop Δ Pe4 is large, and when Δ Pe1 is greater than Δ Pe4, the elastic diaphragm 521 expands towards the cathode tail gas cavity 524, so that the volume of the cathode tail gas cavity 524 is reduced, the pressure drop Δ Pe5 is increased, the difference between Δ Pe1 and Δ Pe4 is balanced, and the cathode and anode stack-out pressure balance is further ensured; when the delta Pe1 is less than the delta Pe4, the elastic diaphragm 521 expands towards the anode tail gas cavity 523, so that the volume of the anode tail gas cavity 523 is reduced, and the pressure drop delta Pe2 is increased to balance the difference between the delta Pe1 and the delta Pe4, thereby ensuring the pile-forming pressure balance of the cathode and the anode.

Case two: fuel cell system rapid variable load operating pressure adaptation process

In the rapid variable load operation process of the fuel cell system, the flow rate of the cathode and anode tail gas can be greatly changed, so that the pressure drop of the 73 pipelines and the 74 pipelines at the tail part of the cathode and anode can be continuously changed, the elastic diaphragm 521 is continuously adjusted to compensate the pressure drop difference formed by the 73 pipelines and the 74 pipelines at the tail part, and the pressure balance of the cathode and anode stack-out tail gas is ensured.

Case three: fuel cell system emergency shutdown pressure adaptation process

When the fuel cell system encounters a fault condition and an emergency shutdown occurs, the load 603 is emergently disconnected, the fuel cell stack 1 stops outputting electric energy, the hydrogen and air supply valves at the front end of the fuel cell stack 1 are emergently closed, because the electrochemical reaction of the fuel cell stack 1 stops, the amount of gas discharged by cathode and anode tail gas can be instantaneously and suddenly increased, the pressure drop difference formed by the tail 73 pipeline and the 74 pipeline is instantaneously increased due to the difference of the cathode and anode tail gas discharge rates, the elastic diaphragm 521 is instantaneously deformed to compensate the pressure drop difference formed by the tail 73 pipeline and the 74 pipeline, the pressure balance of the cathode and anode stack tail gas is ensured, a buffer space is provided for pressure fluctuation, and the pressure fluctuation of the cathode and anode stack tail gas is avoided from being greatly fluctuated.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.

Also, while for purposes of simplicity of explanation, the various method embodiments described above are shown as a series of acts or combination, it will be appreciated by those skilled in the art that the present invention is not limited by the illustrated ordering of acts, as some steps may occur in other orders or concurrently in accordance with the invention.