Method and device for controlling nitrogen removal of anode of fuel cell

Abstract

The invention discloses a fuel cell anode nitrogen removal control method and device, and the method comprises the steps: controlling a switch valve to be opened, a first drainage valve to be closed, a second drainage valve to be closed, and a nitrogen removal valve to be closed in an initial state of an electric pile; when the electric pile works, the liquid level of a water storage tank of the first-stage gas-water separator and the liquid level of a water storage tank of the second-stage gas-water separator are obtained; and if the liquid level of the water storage tank of the second-stage gas-water separator is smaller than the liquid level upper limit, the second drainage valve is in a closed state, and the interval duration from last closing of the nitrogen removal valve is larger than the first duration, the switching valve is controlled to be closed, and the nitrogen removal valve is controlled to be opened. Therefore, the water content of the gas discharged by the two-stage water diversion and nitrogen removal valve is low, the amount of the discharged gas can be accurately controlled, the nitrogen removal time is shortened, and the hydrogen utilization rate is increased. In addition, the two-stage water diversion channel is cut off through the switching valve and the one-way valve, and hydrogen pressure fluctuation in the system can be avoided when the nitrogen removal valve discharges gas.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a method and device for controlling nitrogen exhaust from an anode of a fuel cell. Background Art

[0002] During the operation of the fuel cell system, impurities in the anode gas and nitrogen that penetrates from the cathode to the anode will continue to accumulate during the hydrogen circulation process. If they are not discharged in time, the anode hydrogen concentration will decrease, causing the performance of the fuel cell system to decline and even causing reverse polarity.

[0003] The fuel cell system generally discharges impurity gases through a nitrogen exhaust valve. However, when the nitrogen exhaust valve is opened, the pressure at the inlet and outlet of the anode of the fuel cell stack will fluctuate greatly, and the pressure difference between the inlet and outlet of the anode will increase, which can easily cause the performance of the fuel cell stack to deteriorate or even cause irreversible mechanical damage.

[0004] In addition, when the anode of the fuel cell system discharges nitrogen, the amount of gas discharged needs to be precisely controlled. If the discharge amount is not enough to reach the required amount, the hydrogen concentration at the anode cannot be fully restored; conversely, if the discharge amount exceeds the required amount, the corresponding fuel gas will be wasted, resulting in low hydrogen utilization. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a method and device for controlling nitrogen exhaust from the anode of a fuel cell, so as to reduce the pressure fluctuation at the inlet and outlet of the anode of the fuel cell stack and increase the utilization rate of hydrogen.

[0006] According to a first aspect of the present invention, a method for controlling nitrogen discharge from an anode of a fuel cell is provided, which is used by a control system for nitrogen discharge from an anode of a fuel cell; the control system for nitrogen discharge from an anode of a fuel cell comprises a primary gas-water separator, a first drain valve, a secondary gas-water separator, a second drain valve, a switch valve, a nitrogen discharge valve and a check valve;

[0007] The inlet of the first-level gas-water separator is connected to the anode outlet of the stack, the first drain valve is connected to the drain port of the first-level gas-water separator, and the second drain valve is connected to the drain port of the second-level gas-water separator; the hydrogen return port of the second-level gas-water separator is connected to the inlet of the one-way valve; the outlet of the one-way valve and the hydrogen return port of the first-level gas-water separator are both connected to the hydrogen circulation confluence port of the stack; the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve, and the outlet of the switch valve is connected to the inlet to the second-level gas-water separator;

[0008] The fuel cell anode nitrogen exhaust control method comprises:

[0009] In the initial state of the stack, the switch valve is controlled to be opened, the first drain valve is controlled to be closed, the second drain valve is controlled to be closed, and the nitrogen exhaust valve is controlled to be closed;

[0010] When the battery stack is working, obtaining the liquid level of the water tank of the primary gas-water separator and the liquid level of the water tank of the secondary gas-water separator;

[0011] If the liquid level in the water tank of the secondary gas-water separator is lower than the upper liquid level limit, the second drain valve is in a closed state, and the interval from the last closure of the nitrogen exhaust valve is greater than a preset first time length, the switch valve is controlled to close, and the nitrogen exhaust valve is controlled to open, so as to discharge the mixed gas in the secondary gas-water separator.

[0012] Optionally, the method further includes:

[0013] If the opening time of the nitrogen exhaust valve is greater than the preset second time, the nitrogen exhaust valve is controlled to be closed and the switch valve is controlled to be opened.

[0014] Optional:

[0015] The first duration is determined according to the nitrogen concentration of the mixed gas.

[0016] Optionally, the method further includes:

[0017] If the liquid level of the water tank of the secondary gas-water separator is greater than or equal to the upper liquid level limit, the second drain valve of the secondary gas-water separator is controlled to open.

[0018] Optionally, the method comprises:

[0019] After the second drain valve is opened, if the liquid level of the water tank of the secondary gas-water separator is lower than the lower limit of the liquid level, the second drain valve of the secondary gas-water separator is controlled to be closed.

[0020] Optionally, the method further includes:

[0021] If the liquid level of the water tank of the primary gas-water separator is greater than or equal to the upper limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to open;

[0022] After the first drain valve is opened, if the liquid level of the water tank of the primary gas-water separator is lower than the lower limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to be closed.

[0023] According to a second aspect of the present invention, there is provided a fuel cell anode nitrogen exhaust control device, comprising:

[0024] An initial module, used to control the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen exhaust valve to close when the stack is in an initial state;

[0025] An acquisition module, used to acquire the liquid level of the water tank of the primary gas-water separator and the liquid level of the water tank of the secondary gas-water separator when the battery stack is working;

[0026] The control module is used to control the switch valve to close and the nitrogen exhaust valve to open when the liquid level of the water tank of the secondary gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last closure of the nitrogen exhaust valve is greater than a preset first time length, so as to discharge the mixed gas in the secondary gas-water separator.

[0027] According to a third aspect of the present invention, there is provided a fuel cell anode nitrogen exhaust control system, comprising:

[0028] Primary gas-water separator, first drain valve, secondary gas-water separator, second drain valve, switch valve, nitrogen exhaust valve and one-way valve;

[0029] Wherein, the inlet of the first-level gas-water separator is connected to the outlet of the anode of the battery stack, the first-level gas-water separator is equipped with a water storage tank, the water storage tank of the first-level gas-water separator is provided with a first-level upper liquid level sensor and a first-level lower liquid level sensor, the drain outlet of the first-level gas-water separator is connected to the first drain valve, the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve, and the outlet of the switch valve is connected to the inlet to the second-level gas-water separator; the second-level gas-water separator is equipped with a water storage tank, the water storage tank of the second-level gas-water separator is provided with a second-level upper liquid level sensor and a second-level lower liquid level sensor, and the drain outlet of the second-level gas-water separator is connected to the second drain valve;

[0030] The exhaust port of the secondary gas-water separator is connected to the nitrogen exhaust valve, and the hydrogen return port of the secondary gas-water separator is connected to the inlet of the one-way valve; the outlet of the one-way valve and the hydrogen return port of the primary gas-water separator are both connected to the hydrogen circulation confluence port of the fuel cell stack;

[0031] The fuel cell anode nitrogen exhaust control system is applicable to the aforementioned fuel cell anode nitrogen exhaust control method when exhausting nitrogen.

[0032] According to a fourth aspect of the present invention, a fuel cell is provided, wherein the fuel cell executes the above-mentioned fuel cell anode nitrogen exhaust control method when exhausting nitrogen.

[0033] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0034] A method and device for controlling nitrogen discharge from the anode of a fuel cell provided in an embodiment of this specification, by controlling the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen discharge valve to close in the initial state of the stack; when the stack is working, the water tank level of the first gas-water separator and the water tank level of the second gas-water separator are obtained; if the water tank level of the second gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last nitrogen discharge valve closure is greater than the preset first time, the switch valve is controlled to close, and the nitrogen discharge valve is controlled to open, so as to discharge the mixed gas in the second gas-water separator. In this way, by adopting the two-stage water separation, the water content of the gas discharged by the nitrogen discharge valve is small, which is conducive to accurately controlling the amount of gas discharged, reducing the nitrogen discharge time, and increasing the utilization rate of hydrogen. In addition, by cutting off the two-stage water separation channel by the switch valve and the one-way valve, the hydrogen pressure fluctuation in the system can be avoided when the nitrogen discharge valve discharges the gas.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0037] Figure 1 A flow chart of a method for controlling nitrogen exhaust from an anode of a fuel cell in an embodiment of the present invention is shown.

[0038] Figure 2 A schematic diagram of a fuel cell anode nitrogen exhaust control system in an embodiment of the present invention is shown.

[0039] Figure 3 A block diagram of a fuel cell anode nitrogen exhaust control device in an embodiment of the present invention is shown.

[0040] legend:

[0041] Primary gas-water separator-1; water storage tank-10, first drain valve-11; switch valve-2, secondary gas-water separator-3, water storage tank-30, second drain valve-31, one-way valve-4, nitrogen exhaust valve-5. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0045] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The applicant found that during the operation of the fuel cell system, impurities in the anode gas and nitrogen that penetrates from the cathode to the anode will continue to accumulate during the hydrogen circulation process. If they are not discharged in time, the anode hydrogen concentration will decrease, resulting in a decrease in the performance of the fuel cell system and even causing reverse polarity.

[0047] The fuel cell system generally discharges impurity gases through a nitrogen exhaust valve. However, when the nitrogen exhaust valve is opened, the pressure at the inlet and outlet of the anode of the fuel cell stack will fluctuate greatly, and the pressure difference between the inlet and outlet of the anode will increase, which can easily cause the performance of the fuel cell stack to deteriorate or even cause irreversible mechanical damage.

[0048] In addition, when the anode of the fuel cell system discharges nitrogen, the amount of gas discharged needs to be precisely controlled. If the discharge amount is not enough to reach the required amount, the hydrogen concentration at the anode cannot be fully restored; conversely, if the discharge amount exceeds the required amount, the corresponding fuel gas will be wasted, resulting in low hydrogen utilization.

[0049] In the prior art, an independent pressure-stabilizing chamber can be set up to increase the volume of the pressure-stabilizing chamber, which can reduce the hydrogen pressure fluctuation of the fuel cell stack to a certain extent and is beneficial to the stability of the anode inlet and outlet pressures of the fuel cell stack. However, in this method, since the nitrogen exhaust valve is connected to the fuel cell stack outlet, the exhausted gas contains a large amount of water vapor, making it difficult to control the nitrogen exhaust amount and the hydrogen utilization rate is low.

[0050] Based on the above situation, an embodiment of the present invention provides a method for controlling nitrogen discharge from the anode of a fuel cell, which adopts a two-level water separation. When the fuel cell stack is working, the anode circulating gas coming out of the stack passes through the first-level gas-water separator and then enters the second-level gas-water separator, and finally circulates back to the stack. The first drain valve and the second drain valve are opened and closed according to the upper and lower liquid level sensor signals, the nitrogen discharge valve is opened and closed according to the calibrated setting time, and the switch valve is opposite to the nitrogen discharge valve switch. When the nitrogen discharge valve is opened, the two-stage water separation channel is cut off by the switch valve and the one-way valve, so that the second-level gas-water separator is completely isolated from the stack, and the circulating gas is circulated back to the stack from the first-level gas-water separator. In this way, the pressure fluctuation of the anode inlet and outlet of the stack can be reduced, and the hydrogen utilization rate can be increased.

[0051] Specifically, combined with Figure 1 The method includes steps 101 to 103:

[0052] Step 101: When the stack is in an initial state, control the switch valve to be opened, the first drain valve to be closed, the second drain valve to be closed, and the nitrogen exhaust valve to be closed;

[0053] In this embodiment, a fuel cell anode nitrogen exhaust control method is used by a fuel cell anode nitrogen exhaust control system; Figure 2 The fuel cell anode nitrogen exhaust control system comprises a primary gas-water separator 1, a first drain valve 11, a secondary gas-water separator 3, a second drain valve 31, a switch valve 2, a nitrogen exhaust valve 5 and a one-way valve 4;

[0054] Wherein, the inlet of the first-level gas-water separator 1 is connected to the outlet of the anode of the battery stack, the first-level gas-water separator 1 is equipped with a water storage tank 10, the water storage tank 10 of the first-level gas-water separator is provided with a first-level upper liquid level sensor and a first-level lower liquid level sensor, the drain outlet of the first-level gas-water separator is connected to the first drain valve 11, the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve 2, and the outlet of the switch valve 2 is connected to the inlet to the second-level gas-water separator 3; the second-level gas-water separator 3 is equipped with a water storage tank 30, the water storage tank 30 of the second-level gas-water separator 3 is provided with a second-level upper liquid level sensor and a second-level lower liquid level sensor, and the drain outlet of the second-level gas-water separator 3 is connected to the second drain valve 31;

[0055] The exhaust port of the secondary gas-water separator 3 is connected to the nitrogen exhaust valve 5, and the hydrogen return port of the secondary gas-water separator 3 is connected to the inlet of the one-way valve 4; the outlet of the one-way valve 4 and the hydrogen return port of the primary gas-water separator 1 are both connected to the hydrogen circulation confluence port of the fuel cell stack.

[0056] In this embodiment, the fuel cell anode nitrogen exhaust control system also includes a controller, which is connected to the first drain valve, the second drain valve, the switch valve, the nitrogen exhaust valve, the one-way valve and each liquid level sensor, and is used to control the opening and closing of the first drain valve, the second drain valve, the switch valve, the nitrogen exhaust valve and the one-way valve.

[0057] In this embodiment, in the initial state of the stack, the controller controls the switch valve to open, the first drain valve of the primary gas-water separator to close, the second drain valve of the secondary gas-water separator to close, and the nitrogen exhaust valve to close. The primary gas-water separator is connected to the secondary gas-water separator.

[0058] Step 102: When the fuel cell stack is working, obtaining the liquid level of the water tank of the primary gas-water separator and the liquid level of the water tank of the secondary gas-water separator;

[0059] After the stack starts working, the generated mixed gas enters the primary gas-water separator from the stack anode outlet. At this time, the mixed gas contains a lot of water, and most of the water can be separated through the primary gas-water separator and the secondary gas-water separator.

[0060] After the mixed gas enters the first-stage gas-water separator, the liquid level in the water tank of the first-stage gas-water separator begins to rise. When the liquid level in the water tank rises and triggers the first-stage upper liquid level sensor, the first drain valve opens to drain water. Then the liquid level in the water tank of the first-stage gas-water separator begins to drop. When the liquid level in the water tank drops to the lower limit of the liquid level, the first-stage lower liquid level sensor is triggered and the first drain valve closes.

[0061] Since the switch valve is open at this time, the primary gas-water separator is connected to the secondary gas-water separator, and the mixed gas enters the secondary gas-water separator through the switch valve.

[0062] Step 103: If the liquid level of the water tank of the secondary gas-water separator is less than the upper liquid level limit, the second drain valve is in a closed state, and the interval time from the last closure of the nitrogen exhaust valve is greater than a preset first time length, the switch valve is controlled to be closed, and the nitrogen exhaust valve is controlled to be opened, so as to discharge the mixed gas in the secondary gas-water separator.

[0063] In this embodiment, when the liquid level in the water tank of the secondary gas-water separator is greater than the upper liquid level limit, the first-level upper liquid level sensor will be triggered, the second drain valve will open, and then the liquid level in the water tank of the secondary gas-water separator will begin to drop. When the liquid level in the water tank drops to the lower liquid level limit, the second-level lower liquid level sensor will be triggered, and the second drain valve will be closed.

[0064] When the liquid level of the water tank of the secondary gas-water separator is less than the upper limit of the liquid level and no drainage is performed, that is to say, the second drain valve is in a closed state. At this time, it is necessary to calculate the interval time from the last time the nitrogen discharge valve was closed. If the interval time is longer than the preset first time, the switch valve will be controlled to close. At this time, the primary gas-water separator is isolated from the secondary gas-water separator. At the same time, the nitrogen discharge valve is controlled to open, so as to discharge the mixed gas in the secondary gas-water separator. Among them, most of the water is separated from the mixed gas in the secondary gas-water separator, and the mixed gas mainly includes nitrogen and hydrogen. Since the secondary gas-water separator is isolated from the primary gas-water separator, and the one-way valve can prevent the mixed gas in the hydrogen return pipeline from entering the secondary gas-water separator, when discharging nitrogen, the hydrogen pressure fluctuation in the system can be effectively prevented.

[0065] After the nitrogen exhaust valve is opened, if the opening time of the nitrogen exhaust valve is greater than the preset second time, the nitrogen exhaust valve is controlled to be closed, and the switch valve is controlled to be opened at the same time, so that the first-level gas-water separator and the second-level gas-water separator are connected again.

[0066] It should be noted that, in one embodiment, the first duration can be determined according to the nitrogen concentration of the mixed gas. If the nitrogen concentration in the mixed gas is high, the first duration can be reduced and the nitrogen emission frequency can be increased.

[0067] In summary, the embodiment of this specification provides a fuel cell anode nitrogen discharge control method and device, by controlling the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen discharge valve to close in the initial state of the stack; when the stack is working, the water tank level of the first gas-water separator and the water tank level of the second gas-water separator are obtained; if the water tank level of the second gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last nitrogen discharge valve closure is greater than the preset first time, then the switch valve is controlled to close, and the nitrogen discharge valve is controlled to open, which is used to discharge the mixed gas in the second gas-water separator. In this way, by adopting the two-stage water separation, the water content of the gas discharged by the nitrogen discharge valve is small, which is conducive to accurately controlling the amount of gas discharged, reducing the nitrogen discharge time, and increasing the utilization rate of hydrogen. In addition, by cutting off the two-stage water separation channel by the switch valve and the one-way valve, the hydrogen pressure fluctuation in the system can be avoided when the nitrogen discharge valve discharges the gas.

[0068] Based on the same inventive concept, Figure 3 As shown, an embodiment of the present invention further provides a fuel cell anode nitrogen exhaust control device, comprising:

[0069] An initial module, used to control the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen exhaust valve to close when the stack is in an initial state;

[0070] An acquisition module, used to acquire the liquid level of the water tank of the primary gas-water separator and the liquid level of the water tank of the secondary gas-water separator when the battery stack is working;

[0071] The control module is used to control the switch valve to close and the nitrogen exhaust valve to open when the liquid level of the water tank of the secondary gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last closure of the nitrogen exhaust valve is greater than a preset first time length, so as to discharge the mixed gas in the secondary gas-water separator.

[0072] Optionally, the control module is further configured to:

[0073] If the opening time of the nitrogen exhaust valve is greater than the preset second time, the nitrogen exhaust valve is controlled to be closed and the switch valve is controlled to be opened.

[0074] Optionally, the control module is further configured to:

[0075] The first duration is determined according to the nitrogen concentration of the mixed gas.

[0076] Optionally, the control module is further configured to:

[0077] If the liquid level of the water tank of the secondary gas-water separator is greater than or equal to the upper liquid level limit, the second drain valve of the secondary gas-water separator is controlled to open.

[0078] Optionally, the control module is further configured to:

[0079] After the second drain valve is opened, if the liquid level of the water tank of the secondary gas-water separator is lower than the lower limit of the liquid level, the second drain valve of the secondary gas-water separator is controlled to be closed.

[0080] Optionally, the control module is further configured to:

[0081] If the liquid level of the water tank of the primary gas-water separator is greater than or equal to the upper limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to open;

[0082] After the first drain valve is opened, if the liquid level of the water tank of the primary gas-water separator is lower than the lower limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to be closed.

[0083] In summary, the embodiment of this specification provides a fuel cell anode nitrogen discharge control method and device, by controlling the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen discharge valve to close in the initial state of the stack; when the stack is working, the water tank level of the first gas-water separator and the water tank level of the second gas-water separator are obtained; if the water tank level of the second gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last nitrogen discharge valve closure is greater than the preset first time, then the switch valve is controlled to close, and the nitrogen discharge valve is controlled to open, which is used to discharge the mixed gas in the second gas-water separator. In this way, by adopting the two-stage water separation, the water content of the gas discharged by the nitrogen discharge valve is small, which is conducive to accurately controlling the amount of gas discharged, reducing the nitrogen discharge time, and increasing the utilization rate of hydrogen. In addition, by cutting off the two-stage water separation channel by the switch valve and the one-way valve, the hydrogen pressure fluctuation in the system can be avoided when the nitrogen discharge valve discharges the gas.

[0084] According to a third aspect of the present invention, there is provided a fuel cell anode nitrogen exhaust control system, comprising:

[0085] Primary gas-water separator, first drain valve, secondary gas-water separator, second drain valve, switch valve, nitrogen exhaust valve and one-way valve;

[0086] Wherein, the inlet of the first-level gas-water separator is connected to the outlet of the anode of the battery stack, the first-level gas-water separator is equipped with a water storage tank, the water storage tank of the first-level gas-water separator is provided with a first-level upper liquid level sensor and a first-level lower liquid level sensor, the drain outlet of the first-level gas-water separator is connected to the first drain valve, the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve, and the outlet of the switch valve is connected to the inlet to the second-level gas-water separator; the second-level gas-water separator is equipped with a water storage tank, the water storage tank of the second-level gas-water separator is provided with a second-level upper liquid level sensor and a second-level lower liquid level sensor, and the drain outlet of the second-level gas-water separator is connected to the second drain valve;

[0087] The exhaust port of the secondary gas-water separator is connected to the nitrogen exhaust valve, and the hydrogen return port of the secondary gas-water separator is connected to the inlet of the one-way valve; the outlet of the one-way valve and the hydrogen return port of the primary gas-water separator are both connected to the hydrogen circulation confluence port of the fuel cell stack;

[0088] The fuel cell anode nitrogen exhaust control system is applicable to the aforementioned fuel cell anode nitrogen exhaust control method when exhausting nitrogen.

[0089] According to a fourth aspect of the present invention, a fuel cell is provided, comprising the above-mentioned fuel cell anode nitrogen exhaust control system, wherein the fuel cell executes the above-mentioned fuel cell anode nitrogen exhaust control method when exhausting nitrogen.

[0090] In summary, the embodiment of this specification provides a fuel cell anode nitrogen discharge control method and device, by controlling the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen discharge valve to close in the initial state of the stack; when the stack is working, the water tank level of the first gas-water separator and the water tank level of the second gas-water separator are obtained; if the water tank level of the second gas-water separator is less than the upper limit of the liquid level, the second drain valve is in a closed state, and the interval time from the last nitrogen discharge valve closure is greater than the preset first time, then the switch valve is controlled to close, and the nitrogen discharge valve is controlled to open, which is used to discharge the mixed gas in the second gas-water separator. In this way, by adopting the two-stage water separation, the water content of the gas discharged by the nitrogen discharge valve is small, which is conducive to accurately controlling the amount of gas discharged, reducing the nitrogen discharge time, and increasing the utilization rate of hydrogen. In addition, by cutting off the two-stage water separation channel by the switch valve and the one-way valve, the hydrogen pressure fluctuation in the system can be avoided when the nitrogen discharge valve discharges the gas.

[0091] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for controlling nitrogen exhaust from anode of a fuel cell, characterized in that: Used by the fuel cell anode nitrogen exhaust control system; the fuel cell anode nitrogen exhaust control system includes a primary gas-water separator, a first drain valve, a secondary gas-water separator, a second drain valve, a switch valve, a nitrogen exhaust valve and a one-way valve; The inlet of the first-level gas-water separator is connected to the anode outlet of the stack, the first drain valve is connected to the drain port of the first-level gas-water separator, and the second drain valve is connected to the drain port of the second-level gas-water separator; the hydrogen return port of the second-level gas-water separator is connected to the inlet of the one-way valve; the outlet of the one-way valve and the hydrogen return port of the first-level gas-water separator are both connected to the hydrogen circulation confluence port of the stack; the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve, and the outlet of the switch valve is connected to the inlet to the second-level gas-water separator; The fuel cell anode nitrogen exhaust control method comprises: In the initial state of the stack, the switch valve is controlled to be opened, the first drain valve is controlled to be closed, the second drain valve is controlled to be closed, and the nitrogen exhaust valve is controlled to be closed; When the battery stack is working, obtaining the liquid level of the water tank of the primary gas-water separator and the liquid level of the water tank of the secondary gas-water separator; If the liquid level in the water tank of the secondary gas-water separator is lower than the upper liquid level limit, the second drain valve is in a closed state, and the interval from the last closure of the nitrogen exhaust valve is greater than a preset first time length, the switch valve is controlled to close, and the nitrogen exhaust valve is controlled to open, so as to discharge the mixed gas in the secondary gas-water separator.

2. The method according to claim 1, characterized in that The method further comprises: If the opening time of the nitrogen exhaust valve is greater than a preset second time, the nitrogen exhaust valve is controlled to be closed and the switch valve is controlled to be opened.

3. The method according to claim 1, characterized in that: The first duration is determined according to the nitrogen concentration of the mixed gas.

4. The method according to claim 1, characterized in that: The method further comprises: If the liquid level of the water tank of the secondary gas-water separator is greater than or equal to the upper liquid level limit, the second drain valve of the secondary gas-water separator is controlled to open.

5. The method according to claim 4, characterized in that The method comprises: After the second drain valve is opened, if the liquid level of the water tank of the secondary gas-water separator is lower than the lower limit of the liquid level, the second drain valve of the secondary gas-water separator is controlled to be closed.

6. The method according to claim 1, characterized in that The method further comprises: If the liquid level of the water tank of the primary gas-water separator is greater than or equal to the upper limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to open; After the first drain valve is opened, if the liquid level of the water tank of the primary gas-water separator is lower than the lower limit of the liquid level, the first drain valve of the primary gas-water separator is controlled to be closed.

7. A fuel cell anode nitrogen exhaust control device, characterized in that: include: The initial module is used to control the switch valve to open, the first drain valve to close, the second drain valve to close, and the nitrogen exhaust valve to close when the stack is in the initial state; An acquisition module, used to acquire the liquid level of the water tank of the first-stage gas-water separator and the liquid level of the water tank of the second-stage gas-water separator when the fuel cell stack is working; The control module is used to control the switch valve to close and the nitrogen exhaust valve to open when the liquid level of the water tank of the secondary gas-water separator is less than the upper liquid level limit, the second drain valve is in a closed state, and the interval time from the last closure of the nitrogen exhaust valve is greater than a preset first time length, so as to discharge the mixed gas in the secondary gas-water separator.

8. A fuel cell anode nitrogen exhaust control system, characterized in that: include: Primary gas-water separator, first drain valve, secondary gas-water separator, second drain valve, switch valve, nitrogen exhaust valve and one-way valve; Wherein, the inlet of the first-level gas-water separator is connected to the outlet of the anode of the battery stack, the first-level gas-water separator is equipped with a water storage tank, the water storage tank of the first-level gas-water separator is provided with a first-level upper liquid level sensor and a first-level lower liquid level sensor, the drain outlet of the first-level gas-water separator is connected to the first drain valve, the exhaust port of the first-level gas-water separator is connected to the inlet of the switch valve, and the outlet of the switch valve is connected to the inlet to the second-level gas-water separator; the second-level gas-water separator is equipped with a water storage tank, the water storage tank of the second-level gas-water separator is provided with a second-level upper liquid level sensor and a second-level lower liquid level sensor, and the drain outlet of the second-level gas-water separator is connected to the second drain valve; The exhaust port of the secondary gas-water separator is connected to the nitrogen exhaust valve, and the hydrogen return port of the secondary gas-water separator is connected to the inlet of the one-way valve; the outlet of the one-way valve and the hydrogen return port of the primary gas-water separator are both connected to the hydrogen circulation confluence port of the fuel cell stack; The fuel cell anode nitrogen exhaust control system is applicable to the fuel cell anode nitrogen exhaust control method described in any one of claims 1 to 6 when exhausting nitrogen.

9. A fuel cell, characterized in that: The fuel cell executes the fuel cell anode nitrogen exhaust control method as described in any one of claims 1-6 when exhausting nitrogen.

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