Air system, fuel cell system and method for improving activity of stack catalyst

Abstract

The invention relates to an air system, a fuel cell system and a method for improving the activity of an electric pile catalyst, the air system is suitable for activation of an electric pile and comprises an air source, an air supply pipeline, an air pressure control assembly and an air flow controller, the air source is communicated with one end of the air supply pipeline, and the other end of the air supply pipeline is communicated with the electric pile; the air supply pipeline comprises a cathode air path and an anode inlet branch, the cathode air path is connected with the cathode inlet end of the electric pile in a breakover mode, the anode inlet branch is connected with the anode inlet end of the electric pile in a breakover mode, and the air pressure control assembly is used for controlling the pressure of air entering the cathode and the anode of the electric pile. The air flow controller is used for controlling the flow of air entering the inlet end of the galvanic pile anode, so that a hydrogen-air interface for removing impurities of a galvanic pile catalyst is formed on the galvanic pile anode, and the recovery and improvement of the activity of the catalyst are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to an air system, a fuel cell system and a method for improving the activity of a fuel cell catalyst. Background Art

[0002] Before the fuel cell system is officially put into use, or when the performance of the fuel cell system stack deteriorates, the membrane electrode assembly of the stack must be activated to restore and improve the performance of the stack. During the catalyst activation stage of the membrane electrode, in order to remove CO and NO that are easily adsorbed on the surface of the platinum catalyst in the anode and cathode of the stack, X 、SO X Impurities such as CO, NO X 、SO X Impurities such as these can poison the platinum catalyst), and in order to restore and enhance the activity of the catalyst, the “empty start” method is usually used in the activation test phase.

[0003] The key to "empty-to-air start" is to form a hydrogen-air interface on the anode side of the fuel cell stack. The hydrogen-air interface will cause a high potential at the cathode of the fuel cell stack, which is conducive to the oxidation and removal of impurity components at the cathode. At the same time, oxygen infiltrates into the anode, which can also oxidize the impurities at the anode and peel them off the platinum catalyst.

[0004] In the related art, air with a higher hydrogen pressure than that on the anode side is usually provided to the cathode side, so that the air on the cathode side naturally permeates through the proton exchange membrane to the anode, thereby forming a hydrogen-air interface with hydrogen on the anode side. However, since the function of the proton exchange membrane is to conduct protons and block gases (such as hydrogen / air, etc.), electrons, water molecules, etc., it is difficult to penetrate the air on the cathode side to the anode by relying solely on the permeation of the proton exchange membrane, and the permeation amount is small. The maintenance time of the hydrogen-air interface on the anode side is short, so that the catalyst layer cannot be effectively oxidized to remove CO and NO that may cause platinum catalyst poisoning. X 、SO X It is difficult to restore or improve the activity of the catalyst due to impurities. Summary of the invention

[0005] The existing technical solutions rely on the permeation of proton exchange membranes, which makes it difficult to permeate the cathode air to the anode in a short time. The permeation of the proton exchange membrane is small, and the maintenance time of the hydrogen-air interface on the anode side is short, which cannot effectively remove CO and NO that cause platinum catalyst poisoning. X 、SO XThe present invention proposes an air system, a fuel cell system and a method for improving the activity of the catalyst in the fuel cell stack, which adopts a system design scheme of directly introducing the cathode side air into the anode inlet, and a corresponding control strategy of introducing the cathode side air into the anode, which can accurately control the air flow and pressure entering the anode side, form an effective hydrogen-air interface on the anode side, and realize the recovery and improvement of the catalyst activity.

[0006] In order to achieve the above-mentioned object, the present invention proposes an air system for improving the activity of a fuel cell catalyst, which is suitable for activation of a fuel cell. The air system comprises an air source, an air supply pipeline, an air pressure control component and an air flow controller. The air source is connected to one end of the air supply pipeline, and the other end of the air supply pipeline is connected to the fuel cell.

[0007] The air supply pipeline includes a cathode air path and an anode inlet branch, the cathode air path can be conductively connected to the cathode inlet end of the fuel cell stack, the anode inlet branch can be conductively connected to the anode inlet end of the fuel cell stack, the air pressure control component is used to control the air pressure entering the positive and negative poles of the fuel cell stack, and the air flow controller is used to control the air flow entering the anode inlet end of the fuel cell stack.

[0008] In some technical solutions, the air system further includes an air exhaust pipeline, one end of which is connected to the cathode outlet of the fuel cell stack, and the other end of which is connected to the exhaust port of the air system;

[0009] The air pressure control assembly includes an air compressor and an air back pressure valve, wherein the air compressor is arranged on the cathode air path, and the air back pressure valve is arranged on the air exhaust pipeline;

[0010] The air flow controller is a cathode air flow valve arranged on the cathode air path.

[0011] In some technical solutions, the air system further includes an air pressure monitoring component, which includes a cathode air path pressure sensor provided at the cathode inlet end of the fuel cell stack and an anode inlet pressure sensor provided at the anode inlet end of the fuel cell stack;

[0012] and / or,

[0013] The air system further includes an air humidifier, the dry side of the air humidifier is connected to the cathode inlet end of the stack through the cathode air path, and the wet side of the air humidifier is connected to the cathode outlet end of the stack through the air exhaust pipeline, and the air humidifier is used to adjust the air humidity.

[0014] An air inlet stop valve is provided on the cathode air path between the dry side of the air humidifier and the cathode inlet end of the stack, an air outlet stop valve is provided on the air discharge pipeline between the wet side of the air humidifier and the cathode outlet end of the stack, and the air back pressure valve is provided on the air discharge pipeline connected to the exhaust port on the wet side of the air humidifier.

[0015] An anode air supply valve is provided on the anode inlet branch.

[0016] According to another aspect of the present invention, the present invention further provides a fuel cell system for improving the activity of a fuel cell catalyst, comprising:

[0017] Battery stack,

[0018] an air system as described above, and

[0019] A hydrogen system comprises a hydrogen source, a hydrogen supply pipeline and a hydrogen pressure control component, wherein the hydrogen source is connected to one end of the hydrogen supply pipeline, the other end of the hydrogen supply pipeline is connected to the anode inlet of the fuel cell stack, and the hydrogen pressure control component is used to control the pressure of hydrogen entering the anode inlet of the fuel cell stack.

[0020] In some technical solutions, the hydrogen supply pipeline includes an anode hydrogen path and a hydrogen pressure regulating branch, the anode hydrogen path can be conductively connected to the anode inlet end of the fuel cell stack, one end of the hydrogen pressure regulating branch is connected to the anode inlet end of the fuel cell stack, and the other end is connected to the exhaust port of the hydrogen system.

[0021] The hydrogen pressure control assembly includes a hydrogen spray valve arranged on the anode hydrogen path, and a hydrogen pressure relief valve arranged on the hydrogen pressure regulating branch path;

[0022] and / or,

[0023] The hydrogen system further comprises a hydrogen exhaust pipeline, one end of which is connected to the anode outlet of the fuel cell stack, and the other end of which is connected to the exhaust port of the hydrogen system.

[0024] The hydrogen exhaust pipeline comprises a water discharge branch and a hydrogen discharge branch which are arranged in parallel. A water discharge valve is arranged on the water discharge branch, and a hydrogen discharge valve is arranged on the hydrogen discharge branch.

[0025] According to another aspect of the present invention, the present invention further provides a method for improving the activity of a fuel cell catalyst, which is used for activating the above-mentioned fuel cell system, comprising the following steps:

[0026] S10: obtaining a first hydrogen pressure of the anode of the fuel cell stack while stopping supplying hydrogen to the anode of the fuel cell stack;

[0027] S20: introducing air into the cathode air path to establish the cathode air path pressure of the fuel cell stack, so as to form a first air pressure at the cathode of the fuel cell stack, wherein the first air pressure is greater than the first hydrogen pressure;

[0028] S30: supplying air to the anode of the fuel cell stack by using the anode inlet branch to form a second air pressure at the anode of the fuel cell stack, wherein the second air pressure is higher than the first hydrogen pressure;

[0029] S40: Stop supplying air to the anode of the fuel cell stack through the anode inlet branch, and control the hydrogen system to supply hydrogen to the anode of the fuel cell stack, wherein a second hydrogen pressure of the supplied hydrogen is higher than the second air pressure.

[0030] Some technical solutions also include:

[0031] S50: Obtain the hydrogen-air mixed pressure at the anode of the fuel cell stack, where the hydrogen-air mixed pressure is the gas pressure of hydrogen at the second hydrogen pressure and air at the second air pressure mixed at the anode of the fuel cell stack, and adjust the cathode air path pressure to form a third air pressure, where the third air pressure is higher than the hydrogen-air mixed pressure.

[0032] Some technical solutions also include:

[0033] S60: Control the fuel cell system to operate at a low-voltage load current for a preset time.

[0034] In some technical solutions, in S50, the pressure difference between the third air pressure and the hydrogen-air mixed pressure is controlled to be between 20 and 40 kPa.

[0035] In some technical solutions, in S60, the average value of the single-chip voltage of the fuel cell stack is monitored in real time, and the average value of the single-chip voltage is controlled to be lower than a preset voltage value.

[0036] The present invention adopts the above technical solution to have at least the following beneficial effects:

[0037] 1. The air system for improving the activity of the catalyst of the fuel cell stack proposed in the present invention directly introduces the air on the cathode side of the fuel cell stack into the anode inlet through the anode inlet branch, and adjusts the air pressure and flow rate entering the anode through the air pressure control component and the air flow controller respectively, so as to form a hydrogen-air interface on the anode side of the fuel cell stack that is conducive to the activation of the catalyst of the fuel cell stack;

[0038] 2. The fuel cell system proposed in the present invention improves the activity of the catalyst in the stack. The air on the cathode side of the stack is directly introduced into the anode inlet by adding an anode inlet branch. The pressure difference between the cathode and cathode is controlled by regulating the air pressure and flow at the anode inlet, and the required amount of air is supplied to the anode. Then, hydrogen with controllable pressure and flow is input into the anode inlet to form an effective hydrogen-air interface on the anode side, and a high potential is formed on the cathode side, which can effectively oxidize and remove CO and NO that cause platinum catalyst poisoning on the cathode side. X 、SO X The air from the cathode side enters the anode and can also effectively oxidize and remove CO and NO in the platinum catalyst on the anode side. X 、SO X Impurities such as chlorine, etc., restore and improve the activity of the anode catalyst, improve and restore the performance of the battery stack, and extend the service life of the battery;

[0039] 3. A method for improving the activity of fuel cell catalysts proposed in the present invention, which adjusts the air pressure and flow rate of the air input at the anode inlet by adjusting the air compressor speed and the opening of the anode air supply valve, and monitors through the anode inlet pressure sensor and the cathode air flow sensor to achieve controllability of the anode input air pressure and flow rate. In the specific execution steps, the residual hydrogen on the anode side is first discharged, and then air with a preset pressure and flow rate is introduced into the anode, and finally hydrogen with a certain flow rate and pressure is introduced into the anode, so that an effective hydrogen-air interface can be formed on the anode side, and used for the activation of the cathode and cathode catalysts, so as to achieve the recovery and improvement of the fuel cell performance;

[0040] 4. The present invention proposes a method for improving the activity of the catalyst of the fuel cell stack, which controls the pressure difference between the positive and negative electrodes of the fuel cell stack to be between 20 and 40 kPa to ensure that the air on the cathode side is replenished to the anode side through the proton exchange membrane without causing damage to the proton exchange membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 A schematic diagram of the structure of a fuel cell system according to an embodiment of the present invention;

[0043] Figure 2 This is a control diagram of the method for improving the activity of fuel cell catalyst according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0045] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0046] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The text of this case specification and the attached Figure 1-2 The abbreviations of the equipment and instruments involved are explained as follows:

[0048] Stack: This article refers to the battery stack;

[0049] AFM: Air Flow Meter, this article refers to the cathode air flow valve;

[0050] AC: Air Compressor, this article refers to air compressor;

[0051] AIC: Air Inter Cooler, this article refers to the intercooler;

[0052] AHM: Air HuMdifier, this article refers to air humidifier;

[0053] ABV: Air By-pass Valve, this article refers to the air bypass valve;

[0054] ACV: Air Cutoff Valve, the air inlet cutoff valve ACV1, air outlet cutoff valve ACV2, anode air supply valve ACV3 involved in this article;

[0055] ABPV: Air Back Pressure Valve, this article refers to the air back pressure valve;

[0056] FSV: Fuel Supply Valve, this article refers to the hydrogen supply valve;

[0057] FIJ: Fuel InJector, this article refers to the hydrogen injection valve;

[0058] FDV: Fuel Drain Valve, this article refers to the drain valve;

[0059] FPV: Fuel Purge Valve, this article refers to the hydrogen purge valve;

[0060] FRV: Fuel Relief Valve, this article refers to the hydrogen pressure relief valve;

[0061] APT: Air Pressure Transducer, the APT12 involved in this article is the cathode air path pressure sensor;

[0062] ATE: Air Temperature Emitter. The ATE12 mentioned in this article is the air inlet temperature sensor.

[0063] FPT: Fuel Pressure Transducer. The FPT11 mentioned in this article is the anode inlet pressure sensor.

[0064] Before a fuel cell is put into use, or when the performance of the stack decays, the stack membrane electrode assembly must be activated and tested. A series of treatment methods are used to activate the catalyst on the electrode surface, thereby improving the efficiency and life of the fuel cell. The most common activation method is electrochemical activation, which means applying voltage to the electrode surface to cause the catalyst on the electrode surface to undergo a redox reaction, thereby activating the catalyst. This method can improve the activity of the catalyst, thereby improving the efficiency and life of the fuel cell.

[0065] Due to the different partial pressures and concentrations of gases at the cathode and anode of the fuel cell and sealing reasons, oxygen on the cathode side will leak or penetrate into the anode through the proton exchange membrane. When the fuel cell stack is started, hydrogen is injected into the anode, causing hydrogen and oxygen to meet at the anode. At this time, a floating hydrogen-oxygen interface is formed at the anode. The design idea of ​​the present invention is to form an effective and stable hydrogen-air interface on the anode side in a controllable manner. At this time, a high potential will be formed on the cathode side, which can effectively oxidize and remove CO and NO that cause platinum catalyst poisoning on the cathode side. X 、SO XThe air from the cathode side enters the anode, which can also effectively oxidize and remove CO and NO in the platinum catalyst on the anode side. X 、SO X Impurities such as impurities can be removed to restore and enhance the activity of the anode side catalyst, thereby improving and restoring the performance of the fuel cell stack.

[0066] In one embodiment of the present invention, an air system for improving the activity of a fuel cell stack catalyst is proposed. The air system is suitable for activating the fuel cell stack and includes an air source, an air supply pipe, an air pressure control component and an air flow controller. The air source is connected to one end of the air supply pipe, and the other end of the air supply pipe is connected to the fuel cell stack.

[0067] The air supply pipeline includes a cathode air path and an anode inlet branch. The cathode air path can be conductively connected to the cathode inlet end of the fuel cell stack, and the anode inlet branch can be conductively connected to the anode inlet end of the fuel cell stack. The air pressure control component is used to control the air pressure entering the cathode and cathode of the fuel cell stack, and the air flow controller is used to control the air flow entering the anode inlet end of the fuel cell stack, thereby forming a hydrogen-air interface at the anode of the fuel cell stack that is beneficial to the removal of impurities from the fuel cell catalyst.

[0068] See also Figure 1 In a specific implementation of this embodiment, the cathode air path is connected to the air source, cathode air flow valve AFM (i.e., air flow controller), air compressor AC, intercooler AIC, air humidifier AHM, air inlet stop valve ACV1, air inlet temperature sensor ATE12, cathode air path pressure sensor APT12 and the cathode inlet of the stack in sequence along the air flow direction. Among them, the cathode air flow valve AFM is used to regulate the air flow on the air supply pipeline, and the air pressure on the air supply pipeline can be adjusted by adjusting the speed of the air compressor AC. The air humidifier AHM is used to adjust the humidity of the supply air. The dry side inlet of the air humidifier AHM is connected to the air source, and the dry side outlet is connected to the cathode of the stack; the air pressure and flow entering the cathode inlet of the stack can be adjusted by adjusting the opening of the air inlet stop valve ACV1, the air inlet temperature sensor ATE12 is used to monitor the air temperature at the cathode inlet of the stack, and the cathode air path pressure sensor APT12 is used to monitor the air pressure entering the cathode inlet of the stack.

[0069] The anode inlet branch is connected to the air outlet of the air humidifier AHM and the anode inlet of the stack. The anode inlet branch is provided with an anode air supply valve ACV3, and the anode inlet pressure sensor FPT11 is arranged at the anode inlet of the stack. The pressure flow of the air entering the anode side is adjusted by adjusting the opening of the anode air supply valve ACV3, and the anode inlet pressure sensor FPT11 is used to monitor the air pressure entering the anode inlet of the stack.

[0070] In addition, it also includes an air discharge pipeline, an air outlet stop valve ACV2 is set on the air discharge pipeline between the cathode outlet of the stack and the wet side inlet of the air humidifier AHM, an air back pressure valve ABPV is set on the air discharge pipeline connecting the wet side outlet of the air humidifier AHM and the exhaust port, and an air bypass valve ABV is set on the air discharge pipeline connecting the intercooler AIC and the exhaust port. Among them, the valve bodies involved are all solenoid valves, which can be selectively controlled for on-off and opening.

[0071] In this embodiment, an anode inlet branch is added to supply air from the cathode to the anode, and an anode air supply valve ACV3 with adjustable opening is provided on the anode inlet branch to accurately control the pressure and flow of air supplied to the anode, thereby providing the possibility of forming an effective hydrogen-air interface.

[0072] In another embodiment of the present invention, a fuel cell system for improving the activity of a fuel cell stack catalyst is provided, which includes, in addition to the above-mentioned air system, a fuel cell stack and a hydrogen system.

[0073] Among them, the hydrogen system includes a hydrogen source, a hydrogen supply pipeline and a hydrogen pressure control component. The hydrogen source is connected to one end of the hydrogen supply pipeline, and the other end of the hydrogen supply pipeline is connected to the anode inlet of the fuel cell stack. The hydrogen pressure control component is used to control the hydrogen pressure entering the anode inlet of the fuel cell stack.

[0074] See also Figure 1 In a specific implementation of the present embodiment, the hydrogen supply pipeline includes an anode hydrogen circuit and a hydrogen pressure regulating branch circuit, the anode hydrogen circuit can be conductively connected to the anode inlet end of the stack, one end of the hydrogen pressure regulating branch circuit is connected to the anode inlet end, and the other end is connected to the exhaust port. Among them, the anode hydrogen circuit is connected to the hydrogen source, the hydrogen supply valve FSV, the hydrogen injection valve FIJ, the anode inlet pressure sensor FPT11 and the anode inlet end of the stack in sequence along the flow direction of hydrogen. Among them, the hydrogen injection valve FIJ is used to adjust the hydrogen pressure, and the anode inlet pressure sensor FPT11 is used to monitor the hydrogen pressure entering the anode inlet end of the stack; a hydrogen pressure relief valve FRV is provided on the hydrogen pressure regulating branch circuit.

[0075] More specifically, the hydrogen system also includes a hydrogen exhaust pipeline, one end of which is connected to the anode outlet of the fuel cell stack, and the other end is connected to the exhaust port. The hydrogen exhaust pipeline includes a drainage branch and a hydrogen exhaust branch arranged in parallel. A drainage valve FDV is arranged on the drainage branch, and a hydrogen exhaust valve FPV is arranged on the hydrogen exhaust branch.

[0076] In this embodiment, an anode inlet branch is added to introduce air from the cathode side of the stack directly into the anode inlet, and the pressure difference between the cathode and cathode is controlled by regulating the air pressure and flow at the anode inlet, and the required amount of air is supplied to the anode; then, an effective hydrogen-air interface is formed on the anode side by inputting hydrogen with controllable pressure and flow into the anode inlet.

[0077] In another embodiment of the present invention, a method for improving the activity of a fuel cell catalyst is provided. The method is started before the fuel cell is officially put into use or when the fuel cell performance decays. Figure 2 , specifically including the following steps:

[0078] S10: obtaining a first hydrogen pressure of the anode of the fuel cell stack while stopping supplying hydrogen to the anode of the fuel cell stack;

[0079] Specifically, the anode inlet pressure sensor FPT11 is used for detection and recording.

[0080] S20: introducing air into the cathode air path to establish the cathode air path pressure of the fuel cell stack, so as to form a first air pressure at the cathode of the fuel cell stack, wherein the first air pressure is greater than the first hydrogen pressure;

[0081] Specifically, the air inlet stop valve ACV1 and the air outlet stop valve ACV2 are opened, and the air compressor AC speed and the air back pressure valve ABPV opening are adjusted to establish the cathode air path pressure.

[0082] S30: supplying air to the anode of the stack by using the anode inlet branch to form a second air pressure at the anode of the stack, wherein the second air pressure is higher than the first hydrogen pressure;

[0083] Specifically, the cathode air path pressure sensor APT12 and the cathode air flow sensor FC20 are monitored. When the cathode air pressure and flow reach the set value, the anode air supply valve ACV3 is opened, and the air pressure entering the anode is monitored in real time through the anode inlet pressure sensor FPT11.

[0084] S40: stopping supplying air to the anode of the fuel cell stack through the anode inlet branch, and controlling the hydrogen system to supply hydrogen to the anode of the fuel cell stack, wherein a second hydrogen pressure of the supplied hydrogen is higher than the second air pressure;

[0085] Specifically, the hydrogen supply valve FSV, the hydrogen injection valve FIJ and the hydrogen pressure relief valve FRV are opened to supply hydrogen to the anode, thereby forming a hydrogen-air interface at the anode of the stack.

[0086] S50: obtaining a hydrogen-air mixed pressure at the anode of the stack, the hydrogen-air mixed pressure being a gas pressure of hydrogen at the second hydrogen pressure and air at the second air pressure mixed at the anode of the stack, adjusting the cathode air path pressure to form a third air pressure, the third air pressure being higher than the hydrogen-air mixed pressure, so that the air at the cathode of the stack enters the anode of the stack through the proton exchange membrane to supplement the air forming the hydrogen-air interface;

[0087] Among them, by adjusting the cathode air circuit pressure, a pressure difference is formed between the anode and the cathode of the fuel cell stack, and the pressure difference is between 20 and 40 kPa, so as to ensure that the air on the cathode side is replenished to the anode through the proton exchange membrane without causing damage to the proton exchange membrane.

[0088] S60: The fuel cell is operated at a low-voltage load current for a preset time to fully remove CO and NO in the cathode and anode of the fuel cell stack that cause platinum catalyst poisoning. X and SO X impurities, restore and enhance the activity of the fuel cell catalyst layer.

[0089] Among them, the low-voltage load current is 30-50A; and by real-time monitoring of the average voltage of the single-chip stack, when the average voltage of the single-chip stack is lower than 0.85V, it proves that the empty start of the fuel cell is completed and enters the next stage of activation.

[0090] The control details in the above steps are described in detail as follows:

[0091] At the beginning of the fuel cell startup, the hydrogen system is in a state of stopping hydrogen supply. Since the first hydrogen pressure remains on the anode side at this time, the cathode air line pressure needs to be established first, and the air pressure entering the anode is adjusted by the air compressor AC and the anode air supply valve ACV3. The second air pressure entering the anode needs to be higher than the first hydrogen pressure to discharge hydrogen through the hydrogen exhaust pipeline. The air flow rate required to enter the anode is positively correlated with the impurities adsorbed on the surface of the platinum catalyst. At the same time, combined with the volume of the anode cavity of the stack and the volume of the anode stack pipeline in the actual project, the pressure of the air entering the anode can be set to be 20 to 40 kPa higher than the cathode side pressure. The pressure difference can be adjusted according to the actual project test. Under the pressure difference control, sufficient power is provided to supply air to the anode to achieve full removal of the first hydrogen pressure remaining at the anode. In the process of introducing air into the anode, the air pressure of the cathode can be fine-tuned to maintain the stability of the system; then hydrogen is supplied to the anode of the stack to form a hydrogen-air interface at the anode. At this time, the second hydrogen pressure of the supplied hydrogen is higher than the second air pressure. Preferably, it can be higher than the first air pressure and the second air pressure by about 20kPa to improve the hydrogen supply efficiency. The mean value of the single-chip voltage of the stack is monitored in real time. It is generally believed that when the mean value of the single-chip voltage is higher than 0.85V, it is considered that an effective hydrogen-air interface has been formed to cause a high potential. If the mean value of the single-chip voltage is higher than 1.2V, the hydrogen injection valve FIJ can be closed. In the process of the anode operating at a low-electric load current, a third air pressure can be formed by adjusting the cathode air path pressure. The third air pressure is higher than the hydrogen-air mixed pressure of the anode, so that the air at the cathode of the stack enters the anode of the stack through the proton exchange membrane to supplement the air forming the hydrogen-air interface. Specifically, the pressure difference between the third air pressure and the hydrogen-air mixture pressure is controlled to be between 20 and 40 kPa to avoid damage to the proton exchange membrane. The average voltage of the single chip is monitored in real time. When the average voltage of the single chip is lower than 0.85 V, it can be considered that the "air-to-air start" is completed and enter the next stage of activation. In the "air-to-air start" stage, it is important to control the anode-cathode pressure difference not to be too low. Usually, the anode-cathode pressure difference does not exceed 50 kPa. The specific decision can be made based on the membrane electrode performance of the specific project.

[0092] This embodiment adjusts the air pressure and flow rate of the air input to the anode inlet by adjusting the air compressor AC speed and the opening of the anode air supply valve ACV3, and monitors through the anode inlet pressure sensor and the cathode air flow sensor to achieve controllability of the anode input air pressure and flow rate. In the specific execution steps, the residual hydrogen on the anode side is first discharged, and then air with a preset pressure and flow rate is introduced into the anode, and finally hydrogen with a certain flow rate pressure is introduced into the anode, so that an effective hydrogen-air interface can be formed on the anode side, which is used for the activation of the cathode and anode catalyst layers, thereby realizing the recovery and improvement of the fuel cell performance.

[0093] In another embodiment of the present invention, a controller is provided, which includes a storage unit and a processing unit, wherein the storage unit is used to store a computer program, and the processing unit is used to execute the steps of the above-mentioned method for improving the activity of the catalyst of the fuel cell stack according to the computer program.

[0094] The controller is electrically connected to the air system, hydrogen system and fuel cell stack respectively. Specifically, it is connected to the equipment, valves and sensor units on each pipeline respectively, and is used to control the start and stop of the equipment, the opening and closing of the valves and the reception and processing of sensor signals (including but not limited to temperature signals, pressure signals, humidity signals and flow signals).

[0095] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

[0096] Those skilled in the art should understand that although the present invention is described in the form of multiple embodiments, not every embodiment includes only one independent technical solution. Such description in the specification is only for the sake of clarity. Those skilled in the art should understand the specification as a whole and regard the technical solutions involved in each embodiment as being able to be combined into different embodiments to understand the scope of protection of the present invention.

Claims

1. An air system for improving the activity of fuel cell catalyst, characterized in that: Suitable for activation of a fuel cell stack, the air system comprises an air source, an air supply pipeline, an air pressure control component and an air flow controller, the air source is connected to one end of the air supply pipeline, and the other end of the air supply pipeline is connected to the fuel cell stack; The air supply pipeline includes a cathode air path and an anode inlet branch, the cathode air path can be conductively connected to the cathode inlet end of the fuel cell stack, the anode inlet branch can be conductively connected to the anode inlet end of the fuel cell stack, the air pressure control component is used to control the air pressure entering the positive and negative poles of the fuel cell stack, and the air flow controller is used to control the air flow entering the anode inlet end of the fuel cell stack.

2. The air system according to claim 1, characterized in that The air system further comprises an air exhaust pipeline, one end of which is connected to the cathode outlet of the fuel cell stack, and the other end of which is connected to the exhaust port of the air system; The air pressure control assembly includes an air compressor and an air back pressure valve, wherein the air compressor is arranged on the cathode air path, and the air back pressure valve is arranged on the air exhaust pipeline; The air flow controller is a cathode air flow valve arranged on the cathode air path.

3. The air system according to claim 2, characterized in that The air system further comprises an air pressure monitoring assembly, wherein the air pressure monitoring assembly comprises a cathode air path pressure sensor disposed at the cathode inlet end of the fuel cell stack and an anode inlet pressure sensor disposed at the anode inlet end of the fuel cell stack; and / or, The air system further includes an air humidifier, the dry side of the air humidifier is connected to the cathode inlet end of the stack through the cathode air path, and the wet side of the air humidifier is connected to the cathode outlet end of the stack through the air exhaust pipeline, and the air humidifier is used to adjust the air humidity. An air inlet stop valve is provided on the cathode air path between the dry side of the air humidifier and the cathode inlet end of the stack, an air outlet stop valve is provided on the air discharge pipeline between the wet side of the air humidifier and the cathode outlet end of the stack, and the air back pressure valve is provided on the air discharge pipeline connected to the exhaust port on the wet side of the air humidifier. An anode air supply valve is provided on the anode inlet branch.

4. A fuel cell system for improving the activity of a fuel cell stack catalyst, characterized in that: include: Battery stack, The air system according to any one of claims 1 to 3, and A hydrogen system comprises a hydrogen source, a hydrogen supply pipeline and a hydrogen pressure control component, wherein the hydrogen source is connected to one end of the hydrogen supply pipeline, the other end of the hydrogen supply pipeline is connected to the anode inlet of the fuel cell stack, and the hydrogen pressure control component is used to control the pressure of hydrogen entering the anode inlet of the fuel cell stack.

5. The fuel cell system according to claim 4, characterized in that: The hydrogen supply pipeline includes an anode hydrogen path and a hydrogen pressure regulating branch, wherein the anode hydrogen path is conductively connected to the anode inlet of the stack, one end of the hydrogen pressure regulating branch is connected to the anode inlet of the stack, and the other end is connected to the exhaust port of the hydrogen system. The hydrogen pressure control assembly includes a hydrogen spray valve arranged on the anode hydrogen path, and a hydrogen pressure relief valve arranged on the hydrogen pressure regulating branch path; and / or, The hydrogen system further comprises a hydrogen exhaust pipeline, one end of which is connected to the anode outlet of the fuel cell stack, and the other end of which is connected to the exhaust port of the hydrogen system. The hydrogen exhaust pipeline comprises a water discharge branch and a hydrogen discharge branch which are arranged in parallel. A water discharge valve is arranged on the water discharge branch, and a hydrogen discharge valve is arranged on the hydrogen discharge branch.

6. A method for improving the activity of a fuel cell catalyst, characterized in that: The activation method for the fuel cell system according to claim 4 or 5 comprises the following steps: S10: obtaining a first hydrogen pressure of the anode of the fuel cell stack while stopping supplying hydrogen to the anode of the fuel cell stack; S20: introducing air into the cathode air path to establish the cathode air path pressure of the fuel cell stack, so as to form a first air pressure at the cathode of the fuel cell stack, wherein the first air pressure is greater than the first hydrogen pressure; S30: supplying air to the anode of the fuel cell stack by using the anode inlet branch to form a second air pressure at the anode of the fuel cell stack, wherein the second air pressure is higher than the first hydrogen pressure; S40: Stop supplying air to the anode of the fuel cell stack through the anode inlet branch, and control the hydrogen system to supply hydrogen to the anode of the fuel cell stack, wherein a second hydrogen pressure of the supplied hydrogen is higher than the second air pressure.

7. The method according to claim 6, characterized in that Also includes: S50: Obtain the hydrogen-air mixed pressure at the anode of the fuel cell stack, where the hydrogen-air mixed pressure is the gas pressure of hydrogen at the second hydrogen pressure and air at the second air pressure mixed at the anode of the fuel cell stack, and adjust the cathode air path pressure to form a third air pressure, where the third air pressure is higher than the hydrogen-air mixed pressure.

8. The method according to claim 6, characterized in that Also includes: S60: Control the fuel cell system to operate at a low-voltage load current for a preset time.

9. The method according to claim 7, characterized in that: In S50, the pressure difference between the third air pressure and the hydrogen-air mixed pressure is controlled to be between 20 and 40 kPa.

10. The method according to claim 8, characterized in that In S60, the average value of the single-cell voltage of the fuel cell stack is monitored in real time, and the average value of the single-cell voltage is controlled to be lower than a preset voltage value.

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