Fuel cell system, control method, fuel cell unit, fuel cell stack, and vehicle

Abstract

The present invention relates to the field of new energy technology, and specifically to a fuel cell system, a control method, a fuel cell unit, a fuel cell stack and a vehicle. The system comprises a fuel cell stack and a gas-liquid separation device, the fuel cell stack comprises a hydrogen outlet manifold, and the gas-liquid separation device is connected to the hydrogen outlet manifold; an auxiliary channel and a tail channel are also provided on the fuel cell stack, and the hydrogen outlet manifold is connected to the auxiliary channel through the tail channel; the system also comprises an auxiliary pump, and the gas-liquid separation device is connected to the auxiliary channel through the auxiliary pump; the present invention uses the auxiliary pump to send the gas separated by the gas-liquid separation device into the auxiliary channel through the auxiliary channel, and then re-flows into the hydrogen outlet manifold through the tail channel; thereby, the airflow velocity in the anode outlet manifold of the fuel cell stack can be increased, thereby enhancing the drainage capacity of the anode outlet manifold of the fuel cell stack; by controlling the rotation speed of the auxiliary pump, the flow rate of the system and the liquid water content in the mixed airflow at the outlet of the fuel cell stack can be adjusted.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and in particular to a fuel cell system, a control method, a fuel cell unit, a fuel cell stack and a vehicle. Background Art

[0002] Water management in proton exchange membrane fuel cell systems is one of the key factors affecting the operation of fuel cell systems. The mixture exiting the stack on the hydrogen side of the fuel cell mainly contains hydrogen, nitrogen and water. The water in the mixture exiting the stack often exists in the form of a mixture of gaseous water and liquid water; and under the influence of parameters such as temperature and pressure, the form of water transforms between gaseous water and liquid water. Due to the huge difference in density between the gas phase and liquid phase of water, the liquid water content is more sensitive to the flow state.

[0003] Reference Figure 1 The existing fuel cell anode side system includes: a hydrogen storage device 1, a pressure reducing valve 2, a safety valve 3, a hydrogen control valve 4, a hydrogen reflux collection port 5, a fuel cell stack 6, a gas-liquid separation device 7, a liquid storage cavity 8, a hydrogen reflux drive device 9, a water discharge valve 10 and a hydrogen discharge valve 11;

[0004] The fuel cell stack 6 is formed by a front end plate 6a and a rear end plate 6d sandwiching a plurality of fuel cell units 6b, and a hydrogen inlet manifold 6c and a hydrogen outlet manifold 6e are provided on the fuel cell stack 6;

[0005] The hydrogen storage device 1, the pressure reducing valve 2, the safety valve 3, the hydrogen control valve 4, the hydrogen reflux collection port 5, and the hydrogen inlet manifold 6c are connected in sequence to realize the hydrogen supply (into the stack) of the hydrogen storage device 1 to the fuel cell 6; the hydrogen outlet manifold 6e is connected to the gas-liquid separation device 7 to realize gas-liquid separation of the hydrogen mixture discharged from the fuel cell 6, and the separated gas is sent back to the hydrogen reflux collection port 5 (reflux system) through the hydrogen reflux driving device 9 (hydrogen circulation pump 12 or ejector), and is mixed with the newly supplied hydrogen to enter the fuel cell 6; the hydrogen discharge valve 11 can also directly discharge hydrogen through the gas-liquid separation device 7; the separated liquid is sent to the liquid storage cavity 8 and discharged by controlling the drain valve 10.

[0006] The existing anode side reflux system circulates the hydrogen-containing mixed gas, which helps to evenly distribute the anode mixed gas concentration. At the same time, the reflux increases the anode gas flow rate, which helps the liquid water generated in the fuel cell unit 6b to flow out of the single-chip battery flow channel along the air flow.

[0007] The existing anode side reflux system circulates with the hydrogen-containing mixed gas, and the liquid water produced by the fuel cell unit 6b is carried out of the monolithic battery hydrogen flow channel with the air flow, and then enters the outlet manifold formed by the stacking of many fuel cell monolithic outlets. The hydrogen mixed gas flow area of ​​the fuel cell anode outlet manifold is larger than the hydrogen flow channel in the monolithic battery, and the air flow velocity is relatively low. Especially in the area near the tail section of the fuel cell stack 6, there is a lack of upstream mixed gas flow, the local air flow velocity is low, and the ability to carry liquid water is poor.

[0008] The fuel cell system may be in various working postures during actual vehicle operation. One of them is that the outlet end of the fuel cell stack 6 is tilted and raised. Figure 2 In this state, the mixed gas flow drains water against gravity, and the water carrying capacity becomes poor, which easily leads to water blockage at the tail end of the fuel cell outlet manifold. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a fuel cell system, control method, fuel cell unit, stack and vehicle that solve the problems of poor drainage capacity and tilted water blockage of the anode outlet manifold of the existing fuel cell stack in the prior art, increase the air flow velocity in the anode outlet manifold, and thus enhance the drainage capacity of the anode outlet manifold.

[0010] In order to solve the above technical problems, the first technical solution adopted by the present invention is:

[0011] A fuel cell system, in particular a fuel cell anode outlet manifold reflux system, the system comprising a fuel cell stack and a gas-liquid separation device, the fuel cell stack comprising a hydrogen outlet manifold, the gas-liquid separation device being in communication with the hydrogen outlet manifold;

[0012] The fuel cell stack is also provided with an auxiliary channel and a tail channel, and the hydrogen outlet manifold is connected with the auxiliary channel through the tail channel;

[0013] The system further comprises an auxiliary pump, and the gas-liquid separation device is connected with the auxiliary channel via the auxiliary pump.

[0014] Preferably, the system further comprises a stack-entry pipeline, which comprises a hydrogen storage device, a pressure reducing valve, a safety valve, a hydrogen control valve, and a hydrogen reflux collection port;

[0015] The fuel cell stack is provided with a hydrogen inlet manifold, and the hydrogen storage device, the pressure reducing valve, the safety valve, the hydrogen control valve, the hydrogen reflux collection port, and the hydrogen inlet manifold are sequentially connected to form a stack entry channel.

[0016] Preferably, the system further comprises a reflux pipeline, which comprises a liquid storage chamber, a hydrogen reflux drive device, a water drain valve and a hydrogen discharge valve;

[0017] The liquid storage cavity, the hydrogen reflux driving device, and the hydrogen exhaust valve are respectively connected to the gas-liquid separation device;

[0018] The drain valve is communicated with the liquid storage cavity.

[0019] In order to solve the above technical problems, the second technical solution adopted by the present invention is:

[0020] A control method of the above fuel cell system, including a flow control method of a fuel cell outlet manifold recirculation system;

[0021] The flow control method of the fuel cell outlet manifold recirculation system comprises:

[0022] Obtain whether the current flow rate of the fuel cell system is greater than a first preset interval, if so, reduce the speed of the auxiliary pump; if not, increase the speed of the auxiliary pump.

[0023] The control method also includes a method for controlling the liquid water content of the mixed gas flow at the outlet of the stack;

[0024] The method for controlling the liquid water content of the mixed gas flow at the stack outlet comprises:

[0025] Obtain whether the liquid water content of the mixed gas flow at the stack outlet of the current fuel cell system is greater than a second preset range, if so, increase the speed of the auxiliary pump; if not, reduce the speed of the auxiliary pump.

[0026] In order to solve the above technical problems, the third technical solution adopted by the present invention is:

[0027] A fuel cell unit comprises a body, wherein the body is provided with a hydrogen inlet, a hydrogen outlet and an auxiliary port.

[0028] Preferably, in the vertical direction, the lowest point of the auxiliary port is higher than the lowest point of the hydrogen outlet.

[0029] In order to solve the above technical problems, the fourth technical solution adopted by the present invention is:

[0030] A fuel cell stack, comprising a front end plate, a rear end plate, a rear end channel and a plurality of the above-mentioned fuel cell units; the fuel cell units are located between the front end plate and the rear end plate;

[0031] The front end plate and the rear end plate are provided with openings corresponding to the hydrogen inlet, the hydrogen outlet, and the auxiliary port;

[0032] The hydrogen inlet of the fuel cell unit and the openings corresponding to the front plate and the rear plate form a hydrogen inlet manifold;

[0033] The hydrogen outlet of the fuel cell unit and the openings corresponding to the front plate and the rear plate form a hydrogen outlet manifold;

[0034] The auxiliary port of the fuel cell unit and the corresponding openings of the front plate and the rear plate form a hydrogen auxiliary port manifold;

[0035] The hydrogen outlet manifold is communicated with the auxiliary port manifold through a tail end channel.

[0036] In order to solve the above technical problems, the fifth technical solution adopted by the present invention is:

[0037] A vehicle adopts one or more of the above-mentioned fuel cell system, the above-mentioned control method, the above-mentioned fuel cell unit or the above-mentioned fuel cell stack.

[0038] The beneficial effects of the present invention are as follows: the gas separated by the gas-liquid separation device is sent into the auxiliary channel through the auxiliary pump, and then flows back into the hydrogen outlet manifold through the tail end channel; thereby, the air flow velocity in the anode outlet manifold of the fuel cell stack can be increased, thereby enhancing the drainage capacity of the anode outlet manifold of the fuel cell stack; the fuel cell anode outlet manifold reflux system is driven by the auxiliary pump, and the flow rate of the fuel cell anode outlet manifold reflux system can be achieved by the rotation speed of the auxiliary pump, which is flexible and adjustable, and can realize different flow rates of outgoing mixed gas to pass through the gas-liquid separation device, thereby indirectly adjusting the liquid water content in the mixed gas flow at the outlet of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural diagram of the anode side system of a fuel cell in the prior art;

[0040] Figure 2 A schematic diagram of the tilted water blocking of a fuel cell stack in the prior art (where g is the direction of gravity acceleration);

[0041] Figure 3 A structural diagram of a fuel cell anode outlet manifold recirculation system according to a specific embodiment of the present invention;

[0042] Figure 4 A schematic diagram of a fuel cell unit according to a specific embodiment of the present invention;

[0043] Figure 5 A schematic diagram of the structure of a battery stack according to a specific embodiment of the present invention;

[0044] Description of labels:

[0045] 1. Hydrogen storage device; 2. Pressure reducing valve; 3. Safety valve; 4. Hydrogen control valve; 5. Hydrogen reflux collection port; 6. Fuel cell; 6a. Front end plate; 6b. Fuel cell unit; 6b1. Hydrogen inlet; 6b2. Hydrogen outlet; 6b3. Auxiliary port; 6c. Hydrogen inlet manifold; 6d. Rear end plate; 6e. Hydrogen outlet manifold; 6f. Auxiliary channel; 6g. Tail end channel; 7. Gas-liquid separation device; 8. Liquid storage cavity; 9. Hydrogen reflux drive device; 10. Drain valve; 11. Hydrogen drain valve; 12. Circulation pump; 13. Liquid water droplets. DETAILED DESCRIPTION

[0046] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0047] Embodiment 1

[0048] A fuel cell anode outlet manifold reflux system, comprising a stack inlet pipeline, a reflux pipeline, a fuel cell stack 6 and a gas-liquid separation device 7, wherein the fuel cell stack 6 comprises a hydrogen outlet manifold 6e, and the gas-liquid separation device 7 is connected to the hydrogen outlet manifold 6b2;

[0049] The fuel cell stack 6 is also provided with an auxiliary channel 6f and a tail channel 6g, and the hydrogen outlet 6b2 manifold is connected with the auxiliary channel 6f through the tail channel 6g;

[0050] The system further comprises an auxiliary pump, and the gas-liquid separation device 7 is connected to the auxiliary channel 6f via the auxiliary pump.

[0051] The inlet pipeline includes a hydrogen storage device 1, a pressure reducing valve 2, a safety valve 3, a hydrogen control valve 4, and a hydrogen reflux collection port 5;

[0052] The fuel cell stack 6 is provided with a hydrogen inlet manifold 6c, and the hydrogen storage device 1, the pressure reducing valve 2, the safety valve 3, the hydrogen control valve 4, the hydrogen reflux collection port 5, and the hydrogen inlet manifold 6c are sequentially connected to form an inlet channel.

[0053] The system further comprises a reflux pipeline, which comprises a liquid storage chamber 8, a hydrogen reflux drive device 9, a water discharge valve 10 and a hydrogen discharge valve 11;

[0054] The liquid storage cavity 8, the hydrogen reflux driving device 9, and the hydrogen discharge valve 11 are respectively connected to the gas-liquid separation device 7;

[0055] The drain valve 10 is communicated with the liquid storage cavity 8 .

[0056] Embodiment 2

[0057] A flow control method for a fuel cell outlet manifold recirculation system according to a first embodiment includes:

[0058] Obtain whether the current flow rate of the fuel cell system is greater than a first preset interval, if so, reduce the speed of the auxiliary pump; if not, increase the speed of the auxiliary pump.

[0059] Embodiment 3

[0060] A method for controlling the liquid water content of the mixed gas flow at the outlet of the stack 6 according to the first embodiment;

[0061] The method for controlling the liquid water content of the mixed gas flow at the outlet of the stack 6 includes:

[0062] Obtain whether the liquid water content of the mixed gas flow at the outlet of the stack 6 of the current fuel cell system is greater than the second preset range, if so, increase the speed of the auxiliary pump; if not, reduce the speed of the auxiliary pump.

[0063] Embodiment 4

[0064] A fuel cell unit 6b comprises a body, wherein the body is provided with a hydrogen inlet 6b1, a hydrogen outlet 6b2 and an auxiliary port 6b3.

[0065] In the vertical direction, the lowest point of the auxiliary port 6b3 is higher than the lowest point of the hydrogen outlet 6b2.

[0066] Embodiment 5

[0067] A fuel cell stack 6, comprising a front end plate 6a, a rear end plate 6d, a rear end channel 6g and a plurality of fuel cell units 6b described in the fourth embodiment; the fuel cell units 6b are located between the front end plate 6a and the rear end plate 6d;

[0068] The front end plate 6a and the rear end plate 6d are provided with openings corresponding to the hydrogen inlet 6b1, the hydrogen outlet 6b2, and the auxiliary port 6b3;

[0069] The hydrogen inlet 6b1 of the fuel cell unit 6b and the corresponding openings of the front plate 6a and the rear plate 6d form a hydrogen inlet 6b1 manifold;

[0070] The hydrogen outlet 6b2 of the fuel cell unit 6b and the corresponding openings of the front end plate 6a and the rear end plate 6d form a hydrogen outlet 6b2 manifold;

[0071] The auxiliary port 6b3 of the fuel cell unit 6b and the corresponding openings of the front end plate 6a and the rear end plate 6d form a hydrogen auxiliary port 6b3 manifold;

[0072] The hydrogen outlet 6b2 manifold is connected to the auxiliary port 6b3 manifold through the tail end channel 6g.

[0073] Embodiment 6

[0074] A vehicle adopts one or more of the fuel cell system described in the first embodiment, the control method described in the second or third embodiment, the fuel cell unit 6b described in the fourth embodiment, or the fuel cell stack 6 described in the fifth embodiment.

[0075] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control method for a fuel cell system, characterized in that: The fuel cell system comprises a fuel cell stack and a gas-liquid separation device, the fuel cell stack comprises a hydrogen outlet manifold, and the gas-liquid separation device is in communication with the hydrogen outlet manifold; The stack is also provided with an auxiliary channel and a tail channel, and the hydrogen outlet manifold is connected to the auxiliary channel through the tail channel; the system also includes an auxiliary pump, and the gas-liquid separation device is connected to the auxiliary channel through the auxiliary pump; The system also includes a stack entry pipeline, which includes a hydrogen storage device, a pressure reducing valve, a safety valve, a hydrogen control valve, and a hydrogen reflux collection port; a hydrogen inlet manifold is provided on the fuel cell stack, and the hydrogen storage device, the pressure reducing valve, the safety valve, the hydrogen control valve, the hydrogen reflux collection port, and the hydrogen inlet manifold are sequentially connected to form a stack entry channel; The system further comprises a reflux pipeline, which comprises a liquid storage cavity, a hydrogen reflux drive device, a water discharge valve and a hydrogen discharge valve; the liquid storage cavity, the hydrogen reflux drive device and the hydrogen discharge valve are respectively connected to the gas-liquid separation device; the water discharge valve is connected to the liquid storage cavity; The control method includes a flow control method for a fuel cell outlet manifold recirculation system; the flow control method for a fuel cell outlet manifold recirculation system includes: obtaining whether the flow of the current fuel cell system is greater than a first preset interval, and if so, reducing the speed of the auxiliary pump; if not, increasing the speed of the auxiliary pump.

2. The control method of the fuel cell system according to claim 1, characterized in that: The control method also includes a method for controlling the liquid water content of the mixed gas flow at the outlet of the fuel cell stack; the method for controlling the liquid water content of the mixed gas flow at the outlet of the fuel cell stack includes: obtaining whether the liquid water content of the mixed gas flow at the outlet of the fuel cell stack of the current fuel cell system is greater than a second preset interval, and if so, increasing the speed of the auxiliary pump; if not, reducing the speed of the auxiliary pump.

3. A fuel cell unit, characterized in that: The fuel cell unit is based on the control method of the fuel cell system in claim 1 or 2, and comprises a main body, on which a hydrogen inlet, a hydrogen outlet and an auxiliary port are provided.

4. The fuel cell unit according to claim 3, characterized in that: In the vertical direction, the lowest point of the auxiliary port is higher than the lowest point of the hydrogen outlet.

5. A battery stack, characterized in that: It comprises a front end plate, a rear end plate, a tail end channel and a fuel cell unit as described in any one of claims 3 or 4; the fuel cell unit is located between the front end plate and the rear end plate; the front end plate and the rear end plate are provided with openings corresponding to a hydrogen inlet, a hydrogen outlet and an auxiliary port; the hydrogen inlet of the fuel cell unit and the openings corresponding to the front end plate and the rear end plate form a hydrogen inlet manifold; the hydrogen outlet of the fuel cell unit and the openings corresponding to the front end plate and the rear end plate form a hydrogen outlet manifold; the auxiliary port of the fuel cell unit and the openings corresponding to the front end plate and the rear end plate form a hydrogen auxiliary port manifold; the hydrogen outlet manifold is connected to the auxiliary port manifold through the tail end channel.

6. A vehicle, characterized in that: Adopt one or more of the control method described in any one of claims 1-2, the fuel cell unit described in any one of claims 3-4 or the fuel cell stack described in claim 5.

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