A control method, device and vehicle of a fuel cell system

Abstract

The present invention discloses a control method, device and vehicle of a fuel cell system, wherein the fuel cell system comprises a controller, an air subsystem and a hydrogen subsystem, wherein the air subsystem comprises a humidity regulating valve, the hydrogen subsystem comprises a hydrogen pump and a drain valve, and the controller is respectively connected to the humidity regulating valve, the hydrogen pump and the drain valve, and the method comprises: obtaining the hydrogen pump power of the hydrogen pump in the running state; determining the current humidity state of the stack based on the hydrogen pump power and the preset hydrogen pump power reference value; if the humidity state is the first-level humidity state, adjusting the opening of the humidity regulating valve; if the humidity state is the second-level humidity state, adjusting the opening of the humidity regulating valve and the drainage time of the drain valve. The control method compares the hydrogen pump power with the normal state reference value, and diagnoses the flooding of the stack in advance, so as to stabilize the water content of the stack within an appropriate range.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell control technology, and in particular to a control method, device and vehicle for a fuel cell system stack. Background Art

[0002] Fuel cells convert part of the Gibbs free energy in the chemical energy of fuel into electrical energy through electrochemical reactions. They are not limited by the Carnot cycle effect and therefore have high thermal efficiency. A fuel cell system for a vehicle generally includes an air system, a hydrogen system, and a cooling system. Hydrogen is used as fuel, and hydrogen and air are introduced into the anode and cathode of the fuel cell respectively for chemical reactions to generate electrical energy. Currently, in the automotive field, proton exchange membrane fuel cells are the most widely used. The hydrogen and air required for the fuel cell reaction enter the gas diffusion layer through the conduction of the anode and cathode flow fields of the bipolar plate, and then enter the catalyst layer through the diffusion layer. Hydrogen is adsorbed by the anode catalyst particles and dissociated into protons and electrons. Protons reach the cathode catalyst layer through the proton exchange membrane in the form of hydrated protons. Electrons cannot pass through the proton exchange membrane and can only reach the cathode from the external circuit electronic load. At the cathode catalyst layer, oxygen atoms, protons, and electrons undergo electrochemical reactions under the action of catalysts to generate water.

[0003] The proton exchange membrane of the fuel cell stack needs to have a certain water content to conduct protons. If the water content is too low, its conductivity will decrease, resulting in an increase in the battery's ohmic voltage loss. When the water content is low, the activity of the catalyst layer interface will also decrease. When the water content is too high, it will cause water flooding inside the stack, which will hinder the transfer of oxygen, reduce the reaction efficiency of the catalyst, prevent the normal electrochemical reaction, and reduce battery performance. The greater the current density, the greater this impact. Flooding of the stack will affect the electrochemical performance and reliable durability of the stack. Therefore, how to control the water content within an appropriate range is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The embodiments of the present application provide a control method, device and vehicle for a fuel cell system stack. The control method can diagnose water flooding in the stack in advance, and adjust the control parameters of the humidity regulating valve and the drain valve according to different water flooding conditions of the stack, so as to stabilize the water content of the stack within an appropriate range.

[0005] In a first aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0006] A fuel cell system with automatic water supply and drainage, the fuel cell system comprising a controller, an air subsystem and a hydrogen subsystem, the air subsystem comprising a humidity regulating valve, the hydrogen subsystem comprising a hydrogen pump and a drain valve, the controller being connected to the humidity regulating valve, the hydrogen pump and the drain valve respectively, the method comprising: obtaining the hydrogen pump power of the hydrogen pump in a running state; determining the current humidity state of the fuel cell stack based on the hydrogen pump power and a preset hydrogen pump power reference value, the humidity state reflecting the flooding condition of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the humidity of the fuel cell stack in a normal state; if the humidity state is a first-level humidity state, adjusting the opening of the humidity regulating valve; if the humidity state is a second-level humidity state, adjusting the opening of the humidity regulating valve and the drainage time of the drain valve.

[0007] Preferably, the humidity state includes a humidity increase state, an excessive humidity state, a slight flooding state, and a severe flooding state.

[0008] Preferably, the current humidity state of the fuel cell stack is determined based on the hydrogen pump power and a preset hydrogen pump power reference value, including: comparing the hydrogen pump power with the hydrogen pump power reference value; if it is determined that the hydrogen pump power is greater than the hydrogen pump power reference value and less than or equal to a first preset power, the hydrogen pump power is in periodic fluctuations, and the cumulative duration of the peak of the periodic fluctuation exceeds a preset percentage within a single timing cycle, then it is determined that the fuel cell stack is in the humidity increasing state, wherein the first preset power is greater than the hydrogen pump power reference value.

[0009] Preferably, if it is determined that the hydrogen pump power is greater than or equal to the second preset power, it is determined that the fuel cell stack is in the excessive humidity state, and the second preset power is greater than the first preset power; if it is determined that the hydrogen pump power is greater than or equal to the third preset power, it is determined that the fuel cell stack is in the slightly flooded state, and the third preset power is greater than the second preset power; if it is determined that the hydrogen pump power is greater than or equal to the fourth preset power, it is determined that the fuel cell stack is in the severely flooded state, and the fourth preset power is greater than the third preset power.

[0010] Preferably, if the humidity state is a first-level humidity state, the opening of the humidity regulating valve is adjusted, including: if the humidity state is an increased humidity state, the opening of the humidity regulating valve is reduced by a first preset opening; if the humidity state is an excessive humidity state, the opening of the humidity regulating valve is reduced by a second preset opening, and the first preset opening is smaller than the second preset opening.

[0011] Preferably, if the humidity state is a second-level humidity state, the opening of the humidity regulating valve and the drainage time of the drain valve are adjusted, including: if the humidity state is a slightly flooded state, the opening of the humidity regulating valve is reduced by the second preset opening, and the drainage time of the drain valve is increased by the first preset time; if the humidity state is a severely flooded state, the opening of the humidity regulating valve is reduced by a third preset opening, and the drainage time of the drain valve is increased by a second preset time, the second preset opening is smaller than the third preset opening, and the first preset time is smaller than the second preset time.

[0012] Preferably, after adjusting the opening of the humidity controlling valve, it also includes: restoring the opening of the humidity controlling valve to an initial opening, and judging whether the battery stack is still in a normal operating state after a preset waiting time, and if not, using the adjusted opening of the humidity controlling valve as the initial opening.

[0013] Preferably, after adjusting the opening of the humidity controlling valve and the drainage time of the drain valve, it also includes: restoring the opening of the humidity controlling valve to the initial opening and restoring the drainage time of the drain valve to the initial time, and judging whether the battery stack is still in a normal operating state after a preset waiting time, if not, taking the adjusted opening of the humidity controlling valve as the initial opening, and taking the adjusted drainage time of the drain valve as the initial time.

[0014] In a second aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0015] A device for implementing the method described in any one of the first aspects above, comprising:

[0016] An acquisition module, used to acquire the hydrogen pump power when the hydrogen pump is in operation;

[0017] A humidity state determination module is used to determine the current humidity state of the fuel cell stack based on the hydrogen pump power and a preset hydrogen pump power reference value, wherein the humidity state reflects the flooding of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the humidity of the fuel cell stack being in a normal state;

[0018] A first-stage regulating module, used for regulating the opening of the humidity regulating valve if the humidity state is the first-stage humidity state;

[0019] The second-level regulating module is used to adjust the opening of the humidity regulating valve and the drainage time of the drainage valve if the humidity state is the second-level humidity state.

[0020] In a third aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0021] A vehicle comprises: a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any one of the methods described in the first aspect when executing the program.

[0022] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0023] The control method of the fuel cell system stack provided by the embodiment of the present invention obtains the hydrogen pump power of the current hydrogen pump in the operating state, analyzes that the higher the stack current, the higher the hydrogen pump speed, the higher the hydrogen pump power, and the corresponding relationship between the hydrogen pump speed and the hydrogen pump power is different when the stack is in different water flooding conditions, and determines the relationship between the water flooding condition of the stack and the hydrogen pump power, that is, the more serious the water flooding of the stack, the greater the power consumption of the hydrogen pump at the same speed, thus, the water flooding condition of the stack can be determined according to the hydrogen pump power and the hydrogen pump power reference value. The control method can diagnose the water flooding condition of the stack in advance through the hydrogen pump power, and adjust the control parameters of the humidity valve and the drain valve according to the different water flooding conditions of the stack, so as to stabilize the water flooding condition of the stack within an appropriate range, which is conducive to avoiding water flooding of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic structural flow chart of a fuel cell system provided by an embodiment of the present invention;

[0026] Figure 2 A flow chart of a control method for a fuel cell system stack provided by an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of a curve showing the relationship between the hydrogen pump speeds under different stack currents provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of a curve showing the relationship between the hydrogen pump speed and the hydrogen pump power under different fuel cell stack flooding conditions provided by an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of a curve showing the change of hydrogen pump power over time under a humidity increase state provided by an embodiment of the present invention;

[0030] Figure 6 A schematic diagram of a flow chart of stack flooding diagnosis and control provided by an embodiment of the present invention;

[0031] Figure 7 A schematic diagram of the structure of a control device for a fuel cell system stack provided in an embodiment of the present invention;

[0032] Figure 8 A schematic structural diagram of a vehicle provided in an embodiment of the present invention.

[0033] Reference numerals:

[0034] 10-air flow meter; 11-air compressor; 12-intercooler; 13-humidity control valve; 131-humidity bypass branch; 14-pressure relief valve; 15-humidifier; 16-air pressure sensor for inlet air; 17-air pressure sensor for outlet air; 18-back pressure valve; 20-proportional valve; 21-hydrogen pressure sensor for inlet hydrogen; 22-hydrogen pressure sensor for outlet hydrogen, 23-gas-liquid separator; 24-hydrogen pump; 25-drain valve; 26-nitrogen discharge valve. DETAILED DESCRIPTION

[0035] The embodiments of the present application provide a control method, device and vehicle for a fuel cell system stack. The control method can diagnose water flooding in the stack in advance, and adjust the control parameters of the humidity regulating valve and the drain valve according to different water flooding conditions of the stack, so as to stabilize the water content of the stack within an appropriate range.

[0036] The overall idea of ​​the technical solution of the embodiment of the present application is as follows:

[0037] A control method for a fuel cell system stack, the fuel cell system comprising a controller, an air subsystem and a hydrogen subsystem, the air subsystem comprising a humidity regulating valve, the hydrogen subsystem comprising a hydrogen pump and a drain valve, the controller being connected to the humidity regulating valve, the hydrogen pump and the drain valve respectively, the method comprising: obtaining the hydrogen pump power of the hydrogen pump in operation; determining the current humidity state of the stack based on the hydrogen pump power and a preset hydrogen pump power reference value, the humidity state reflecting the flooding of the stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the humidity of the stack in a normal state; if the humidity state is a first-level humidity state, adjusting the opening of the humidity regulating valve; if the humidity state is a second-level humidity state, adjusting the opening of the humidity regulating valve and the drainage time of the drain valve.

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] In a first aspect, an embodiment of the present invention provides a method for controlling a fuel cell system stack. Specifically, Figure 1As shown, the fuel cell system includes a controller 200, an air subsystem 300 and a hydrogen subsystem 400, wherein the air subsystem 300 includes a humidity control valve 13, and the hydrogen subsystem 400 includes a hydrogen pump 24 and a drain valve 25. The controller is connected to the humidity control valve 13, the hydrogen pump 24 and the drain valve 25, respectively. Figure 2 As shown, the method includes the following steps S101 to S104:

[0040] Step S101: obtaining the hydrogen pump power of the hydrogen pump in operation.

[0041] It should be noted that, in the fuel cell system provided in the present application, the humidity regulating valve is specifically used to adjust the humidity of the air entering the fuel cell stack, the hydrogen pump is used to adjust the mixing ratio of the hydrogen entering the fuel cell stack inlet, the mixing ratio is the ratio of the hydrogen at the fuel cell stack outlet to the fresh hydrogen, and the drain valve is used to discharge part of the gas or part of the water.

[0042] In a specific embodiment, Figure 1 As shown, the air subsystem in the fuel cell system may specifically include: an air flow meter 10, an air compressor 11, an intercooler 12, a humidity control valve 13, a humidity bypass branch 131, a pressure relief valve 14, a humidifier 15, an inlet air pressure sensor 16, an outlet air pressure sensor 17, and a back pressure valve 18.

[0043] The humidity control valve 13 is a three-way valve. When the humidity control valve 13 is fully closed, the air flow direction is the humidity control valve 13, the humidity bypass branch 131, and the battery stack; when the humidity control valve 13 is fully opened, the air flow direction is the humidity control valve 13, the humidifier 15, and the battery stack; when the humidity control valve 13 is between fully open and fully closed, part of the air at the outlet of the humidity control valve 13 enters the humidifier 15, and the other part enters the humidity bypass branch 131. The larger the opening of the humidity control valve 13, the greater the humidity of the air inlet of the battery stack, and the smaller the opening of the humidity control valve 13, the smaller the humidity of the air inlet of the battery stack.

[0044] The airflow direction of the entire air subsystem is: air flow meter 10, air compressor 11, intercooler 12, humidity control valve 13, humidifier 15, inlet air pressure sensor 16, fuel cell stack, outlet air pressure sensor 17, back pressure valve 18. When the pressure relief valve 14 is opened, a part of the air enters the pressure relief valve 14 to bypass.

[0045] The hydrogen subsystem may specifically include: a proportional valve 20, a hydrogen pressure sensor 21 for entering the stack, a hydrogen pressure sensor 22 for exiting the stack, a gas-liquid separator 23, a hydrogen pump 24, a drain valve 25, and a nitrogen exhaust valve 26. The gas flow direction of the entire hydrogen system is: a proportional valve 20, a hydrogen pressure sensor 21 for entering the stack, a fuel cell, a hydrogen pressure sensor 22 for exiting the stack, a gas-liquid separator 23, and a hydrogen pump 24. The function of the hydrogen pump 24 is to mix the hydrogen at the outlet of the fuel cell with the fresh hydrogen at the outlet of the proportional valve 20 and enter the inlet of the fuel cell, so as to realize the recycling of hydrogen and provide a hydrogen metering ratio. When the drain valve 25 is opened, part of the gas or water at the outlet of the gas-liquid separator 23 enters the drain valve 25, and when the nitrogen exhaust valve 26 is opened, part of the gas at the outlet of the gas-liquid separator 23 enters the nitrogen exhaust valve 26.

[0046] The controller 200 is respectively connected to the air flow meter 10, the air compressor 11, the intercooler 12, the humidity regulating valve 13, the pressure relief valve 14, the humidifier 15, the stack inlet air pressure sensor 16, the stack outlet air pressure sensor 17, the back pressure valve 18, the proportional valve 20, the stack inlet hydrogen pressure sensor 21, the stack outlet hydrogen pressure sensor 22, the hydrogen pump 24, the drain valve 25 and the nitrogen exhaust valve 26, and mainly detects the signals of various actuators and sensors, such as the speed of the air compressor 11, the opening of the back pressure valve 18, the air flow, voltage, current, etc., and effectively controls them, and diagnoses the operating status of the fuel cell stack and components.

[0047] The method provided in this embodiment is applied to a controller to execute each step, or is applied to a control device that is communicatively connected to the controller to execute each step, and there is no limitation on this.

[0048] Specifically, the method for obtaining the hydrogen pump power when the hydrogen pump is in operation includes: obtaining the speed of the current hydrogen pump in operation, and calculating the hydrogen pump power according to the speed and a preset model formula, wherein the preset model formula is a relationship between the speed and power of the hydrogen pump, for example: power (w) = 2π × torque (Nm) × speed (rpm) / 60. Alternatively, obtaining the hydrogen pump power when the hydrogen pump is in operation may also include: obtaining operation data collected by the fuel cell controller of the vehicle, and determining the hydrogen pump power based on the operation data.

[0049] Step S102: Based on the hydrogen pump power and a preset hydrogen pump power reference value, determine the current humidity state of the fuel cell stack, wherein the humidity state reflects the flooding condition of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the normal humidity of the fuel cell stack.

[0050] The humidity state of the battery stack provided in the present application may include: humidity increase state, excessive humidity state, slight flooding state and severe flooding state, wherein the degree of flooding gradually increases from humidity increase state, excessive humidity state, slight flooding state to severe flooding state. Of course, in the specific implementation process, there are many kinds of humidity states of the battery stack, for example, it may also include: moderate flooding state, wherein the degree of flooding gradually increases from humidity increase state, excessive humidity state, slight flooding state, moderate flooding state to severe flooding state.

[0051] First, the severity of flooding is divided into five states from low to high, including normal operation, increased humidity, excessive humidity, minor flooding, and severe flooding. The air humidity at the stack inlet is set to correspond to different flooding severity levels. Specifically, when the stack of the fuel cell system is in normal operation, the air humidity at the stack inlet is generally around 40%; when the stack is in an increased humidity state, the air humidity at the stack inlet is generally above 80%; when the stack is in an excessive humidity state, a minor flooding state, or a severe flooding state, the air humidity at the stack inlet is generally above 100%, and the liquid water inside the stack gradually increases.

[0052] Specifically, before determining the current humidity state of the fuel cell stack based on the hydrogen pump power and a preset hydrogen pump power reference value, it may also include: establishing a corresponding relationship between the hydrogen pump speed and the hydrogen pump power under different fuel cell stack humidity states.

[0053] Specifically, by setting the humidity state of the fuel cell stack to normal operation state, increased humidity state, excessive humidity state, slight water flooding state and severe water flooding state, the hydrogen pump speed is adjusted for each humidity state to obtain the corresponding hydrogen pump power at different hydrogen pump speeds.

[0054] As an example, the method for adjusting the speed of the hydrogen pump may include: adjusting the current of the fuel cell stack and adjusting the speed of the hydrogen pump.

[0055] Specifically, under normal operating conditions, when the fuel cell system power output is low and the stack current is small, the required hydrogen flow rate for recirculation from the stack outlet to the hydrogen pump is also small, and the controller controls the target speed of the hydrogen pump to be low; when the fuel cell system power output is high and the stack current is large, the required hydrogen flow rate for recirculation from the stack outlet to the hydrogen pump is also large, and the controller controls the target speed of the hydrogen pump to be high. In short, the higher the stack current, the higher the speed of the hydrogen pump. Figure 3 Shown is the corresponding hydrogen pump speed under different stack currents.

[0056] like Figure 4As shown in the figure, the corresponding relationship curve between the hydrogen pump speed and the hydrogen pump power under different severity of stack flooding analyzed in this application, the horizontal axis is the hydrogen pump speed, the vertical axis is the hydrogen pump power, a is the normal operation state, b is the humidity increase state, c is the excessive humidity state, d is the slight flooding state, and e is the serious flooding state. It can be seen from the figure that the more serious the stack flooding, the greater the hydrogen pump power consumption at the same speed, that is, when the hydrogen pump power is constant, the greater the hydrogen pump power, the more serious the stack flooding.

[0057] Among them, the hydrogen pump power in the humidity increased state is very close to that in the normal operating state, with a power difference of less than 10%. The hydrogen pump power in the excessive humidity state is 10%-30% higher than that in the normal operating state. The hydrogen pump power in the slight flooding state is 30%-50% higher than that in the normal operating state. The hydrogen pump power in the severe flooding state is more than 50% higher than that in the normal operating state.

[0058] Next, the humidity status of the battery stack includes: humidity increase status, excessive humidity status, slight flooding status and severe flooding status. Figure 2 Taking the execution of the steps in the method by the controller as an example, the control method provided by this embodiment is described in detail.

[0059] In a specific embodiment, the current humidity state of the fuel cell stack is determined based on the hydrogen pump power and a preset hydrogen pump power reference value, which may specifically include: comparing the hydrogen pump power with the hydrogen pump power reference value; if it is determined that the hydrogen pump power is greater than the hydrogen pump power reference value and is less than or equal to the first preset power, the hydrogen pump power is in periodic fluctuations, and the cumulative duration of the peak of the periodic fluctuation exceeds a preset percentage within a single timing cycle, then it is determined that the fuel cell stack is in an increased humidity state, wherein the first preset power is greater than the hydrogen pump power reference value.

[0060] Specifically, the hydrogen pump power reference value can be obtained through experimental calibration, that is, the humidity of the fuel cell stack is stabilized in normal operating conditions, the corresponding hydrogen pump power under different hydrogen pump powers is measured, the operation is repeated at least 20 times, the 20 sets of data are averaged, and the hydrogen pump power corresponding to the normal humidity of the fuel cell stack is determined.

[0061] Optionally, the first preset power is 110% of the hydrogen pump power reference value.

[0062] Specifically, when the stack is in normal operation, the power of the hydrogen pump is generally a horizontal curve with relatively small fluctuations. Since the hydrogen pump power when the stack is in a state of increased humidity is slightly different from that in a normal operation state, in order to more accurately determine whether the current stack is in a state of increased humidity, this application analyzes the hydrogen pump power in a state of increased humidity and establishes a curve of the relationship between the hydrogen pump power in a state of increased humidity and time, such as Figure 5As shown, the horizontal axis is time and the vertical axis is hydrogen pump power. Under the condition of increased humidity, the power of the hydrogen pump fluctuates periodically, f is the peak, g is the trough, and the trough is the hydrogen pump power when the humidity of the stack is in a normal state, where the peak power value is 20%-30% higher than the trough value. When the cumulative time of the peak in a timing cycle (for example: 60s) exceeds the preset percentage of the timing cycle (for example: 50%), the stack is diagnosed as a state of increased humidity.

[0063] In a specific embodiment, the current humidity state of the fuel cell stack is determined based on the hydrogen pump power and a preset hydrogen pump power reference value, and may also include: if it is determined that the hydrogen pump power is greater than or equal to the second preset power, then the fuel cell stack is determined to be in an excessive humidity state, and the second preset power is greater than the first preset power; if it is determined that the hydrogen pump power is greater than or equal to the third preset power, then the fuel cell stack is determined to be in a slightly flooded state, and the third preset power is greater than the second preset power; if it is determined that the hydrogen pump power is greater than or equal to the fourth preset power, then the fuel cell stack is determined to be in a severely flooded state, and the fourth preset power is greater than the third preset power.

[0064] It should be noted that the second preset power, the third preset power and the fourth preset power here can be obtained through experimental calibration.

[0065] Optionally, the second preset power may be between 110% and 130% of the hydrogen pump power reference value, the third preset power may be between 130% and 150% of the hydrogen pump power reference value, and the fourth preset power may be 150% of the hydrogen pump power reference value.

[0066] Step S103: if the humidity state is the first level humidity state, adjusting the opening of the humidity control valve;

[0067] Step S104: If the humidity state is the second level humidity state, the opening of the humidity control valve and the drainage time of the drainage valve are adjusted.

[0068] In a specific embodiment, the first-level humidity state includes a humidity increase state and an excessive humidity state. If the humidity state is the first-level humidity state, the opening of the humidity regulating valve is adjusted, which may include: if the humidity state is an increased humidity state, the opening of the humidity regulating valve is reduced to a first preset opening; if the humidity state is an excessive humidity state, the opening of the humidity regulating valve is reduced to a second preset opening, and the first preset opening is smaller than the second preset opening.

[0069] In a specific embodiment, the second-level humidity state includes a slight flooding state and a severe flooding state. If the humidity state is the second-level humidity state, the opening of the humidity regulating valve and the drainage time of the drain valve are adjusted, including: if the humidity state is a slight flooding state, the opening of the humidity regulating valve is reduced by a second preset opening, and the drainage time of the drain valve is increased by a first preset time; if the humidity state is a severe flooding state, the opening of the humidity regulating valve is reduced by a third preset opening, and the drainage time of the drain valve is increased by a second preset time, the second preset opening is smaller than the third preset opening, and the first preset time is smaller than the second preset time.

[0070] It should be noted that the first preset opening, the second preset opening, the third preset opening, the first preset time length and the second preset time length here can all be obtained through test calibration.

[0071] Optionally, the first preset opening can be between 4%-6% of the initial opening, for example: 5% initial opening, the first preset opening can be between 8%-12% of the initial opening, for example: 10% initial opening, and the second preset opening can be between 14%-16% of the initial opening, for example: 15% initial opening.

[0072] Optionally, the first preset time may be between 10%-30% of the initial drainage time, for example, 20% of the initial drainage time, and the second preset time may be between 40%-60% of the initial drainage time, for example, 50% of the initial drainage time.

[0073] Specifically, the humidity control valve can adjust the humidity of the air entering the battery stack. Reducing the opening of the humidity control valve can reduce the humidity of the air in the battery stack. The drain valve is used to discharge part of the gas or water at the outlet of the gas-liquid separator. Increasing the drainage time of the drain valve can reduce the water content in the battery stack. When the humidity state of the battery stack is in the first level, the opening of the humidity control valve is adjusted according to the degree of flooding to effectively control the humidity state of the battery stack; when the humidity state of the battery stack is in the second level, the opening of the adjustment valve and the drainage time of the drain valve are adjusted to effectively control the humidity state of the battery stack.

[0074] For example, if Figure 6 As shown, the process of diagnosing and controlling the flooding state of the fuel cell stack may include: when it is determined that the hydrogen pump power is greater than the reference value and does not exceed 10% of the reference value under normal operating conditions within a 60-second timing cycle, further determine whether the hydrogen pump fluctuates periodically and whether the cumulative duration of the peak exceeds 50% of a single timing cycle. If so, it is determined to be a humidity increase state, and at the same time, the opening of the humidity control valve is reduced by 5% of the total opening, and then the next judgment is made. For example: the initial opening of the humidity control valve is half open (50%). When it is determined to be a humidity increase state, the opening of the humidity control valve is reduced to 45%.

[0075] When the hydrogen pump power increases by 10%-30% over the normal operating baseline value, the fuel cell stack is diagnosed as being in a state of excessive humidity. At the same time, the humidity control valve opening is reduced by 10% of the total opening. After 60 seconds, the next diagnosis is performed. For example, if the initial opening of the humidity control valve is half open, when it is judged to be in a state of excessive humidity, the opening of the humidity control valve is reduced to 40%.

[0076] When the hydrogen pump power increases by more than 30%-50% of the normal operating baseline value, the fuel cell stack is diagnosed as slightly flooded. At the same time, the humidity control valve opening is reduced by 10% of the total opening, and the drainage time of the drain valve is increased by 20% on the original basis. After 60 seconds of timing, the next diagnosis is performed. For example: the initial opening of the humidity control valve is half open, and the initial drainage time of the drain valve is 1 minute. When it is judged to be slightly flooded, the opening of the humidity control valve is reduced to 40%, and the drainage time of the drain valve is adjusted to 1 minute and 12 seconds.

[0077] When the hydrogen pump power increases by more than 50% of the normal operating baseline value, the fuel cell stack is diagnosed as being in a severe flooding state. At the same time, the humidity control valve opening is reduced by 15% of the total opening, and the drainage time of the drain valve is increased by 50% on the original basis. After 60 seconds of timing, the next diagnosis is performed. For example: the initial opening of the humidity control valve is half open, and the initial drainage time of the drain valve is 1 minute. When it is judged to be in a severe flooding state, the opening of the humidity control valve is reduced to 35%, and the drainage time of the drain valve is adjusted to 1 minute and 30 seconds.

[0078] Furthermore, in order to match the opening of the humidity control valve with the operation of the current fuel cell system and reduce the frequent adjustment of the humidity control valve, in a specific embodiment, after adjusting the opening of the humidity control valve, it can also include: restoring the opening of the humidity control valve to the initial opening, and judging whether the fuel cell stack is still in a normal operating state after a preset waiting time, if not, using the adjusted opening of the humidity control valve as the initial opening.

[0079] In order to make the opening of the humidity controlling valve and the drainage time of the drain valve match the operation of the current fuel cell system and reduce the frequent adjustment of the humidity controlling valve and the drain valve, after adjusting the opening of the humidity controlling valve and the drainage time of the drain valve, it can also include: restoring the opening of the humidity controlling valve to the initial opening and restoring the drainage time of the drain valve to the initial time, and judging whether the fuel cell stack is still in normal operation after a preset waiting time, if not, taking the adjusted opening of the humidity controlling valve as the initial opening, and taking the adjusted drainage time of the drain valve as the initial time.

[0080] Specifically, after adopting different humidity control valve openings and drain valve durations according to different water flooding fault states of the battery stack, the battery stack state is restored to normal operating state, and another judgment is made after a preset waiting time to determine whether the battery stack is in normal operating state (that is, whether the humidity state of the battery stack is in normal operating state). If not, the opening of the humidity control valve after the above adjustment is used as the initial opening, and the drainage time of the drain valve after the above adjustment is used as the initial time. If so, the opening of the humidity control valve adopts the initial opening, and the drainage time of the drain valve adopts the original time.

[0081] Here, judging after a preset waiting time can effectively avoid measurement errors. Optionally, the preset waiting time can be 60s.

[0082] As an implementation mode, the method for determining whether the fuel cell stack is in a normal operating state may include: obtaining a hydrogen pump power value at a current hydrogen pump speed, and determining a current humidity state of the fuel cell stack.

[0083] In summary, a control method for a fuel cell system stack provided by an embodiment of the present invention can quantify the severity of stack flooding by comparing the hydrogen pump power fluctuation curve and the hydrogen pump power with the normal state reference value, and adjust the control parameters of the humidity regulating valve and the drain valve according to different stack flooding states to avoid stack flooding. Compared with the traditional fuel cell system stack flooding fault diagnosis method, this control method does not need to rely on hydrogen pressure sensors and stack impedance meters, avoids misjudgment caused by sensor signal fluctuations, has lower costs and better effects.

[0084] In the second aspect, based on the same inventive concept, this embodiment provides a control device for a fuel cell system stack, such as Figure 7 As shown, the device comprises:

[0085] An acquisition module 401 is used to acquire the hydrogen pump power when the hydrogen pump is in operation;

[0086] The humidity state determination module 402 is used to determine the current humidity state of the fuel cell stack based on the hydrogen pump power and a preset hydrogen pump power reference value, wherein the humidity state reflects the flooding of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the normal humidity of the fuel cell stack;

[0087] The first-stage adjustment module 403 is used to adjust the opening of the humidity control valve if the humidity state is the first-stage humidity state;

[0088] The second-level regulating module 404 is used to adjust the opening of the humidity regulating valve and the drainage time of the drainage valve if the humidity state is the second-level humidity state.

[0089] In an optional embodiment, the humidity state includes an increased humidity state, an excessive humidity state, a slight flooding state, and a severe flooding state.

[0090] In an optional embodiment, the humidity state determination module 402 is specifically used to: compare the hydrogen pump power with the hydrogen pump power reference value; if it is determined that the hydrogen pump power is greater than the hydrogen pump power reference value and is less than or equal to the first preset power, the hydrogen pump power is in periodic fluctuations, and the peak of the periodic fluctuation lasts for more than a preset percentage in a single timing cycle, then it is determined that the fuel cell stack is in an increased humidity state, wherein the first preset power is greater than the hydrogen pump power reference value.

[0091] In an optional embodiment, the humidity status determination module 402 is specifically used to: if it is determined that the hydrogen pump power is greater than or equal to the second preset power, then it is determined that the fuel cell stack is in an excessive humidity state, and the second preset power is greater than the first preset power; if it is determined that the hydrogen pump power is greater than or equal to the third preset power, then it is determined that the fuel cell stack is in a slightly flooded state, and the third preset power is greater than the second preset power; if it is determined that the hydrogen pump power is greater than or equal to the fourth preset power, then it is determined that the fuel cell stack is in a severely flooded state, and the fourth preset power is greater than the third preset power.

[0092] In an optional embodiment, the first-stage adjustment module 403 is specifically used to: if the humidity state is an increased humidity state, reduce the opening of the humidity control valve by a first preset opening; if the humidity state is an excessive humidity state, reduce the opening of the humidity control valve by a second preset opening, and the first preset opening is smaller than the second preset opening.

[0093] In an optional embodiment, the second-stage adjustment module 404 is specifically used to: if the humidity state is a slight flooding state, reduce the opening of the humidity regulating valve by a second preset opening, and increase the drainage time of the drain valve by a first preset time; if the humidity state is a severe flooding state, reduce the opening of the humidity regulating valve by a third preset opening, and increase the drainage time of the drain valve by a second preset time, the second preset opening is smaller than the third preset opening, and the first preset time is smaller than the second preset time.

[0094] In an optional embodiment, the device also includes: a first judgment module, used to restore the opening of the humidity control valve to the initial opening, and determine whether the battery stack is still in a normal operating state after a preset waiting time. If not, the adjusted opening of the humidity control valve is used as the initial opening.

[0095] In an optional embodiment, the device also includes: a second judgment module, used to restore the opening of the humidity controlling valve to the initial opening and the drainage time of the drain valve to the initial time, and determine whether the battery stack is still in normal operation after a preset waiting time. If not, the adjusted opening of the humidity controlling valve is used as the initial opening, and the adjusted drainage time of the drain valve is used as the initial time.

[0096] The specific implementation process can refer to the corresponding description in the system embodiment provided in the first aspect above, and will not be repeated here.

[0097] An embodiment of the present invention provides a device for implementing the method described in any one of the first aspects above. Its implementation principle and technical effects are the same as those of the aforementioned method embodiments. For the sake of brief description, for matters not mentioned in the device embodiment, reference can be made to the corresponding contents in the aforementioned method embodiments.

[0098] On the third aspect, based on the same inventive concept, Figure 8 As shown, this embodiment provides a vehicle 500, including: a memory 501, a processor 502, and a computer program 503 stored in the memory and executable on the processor, and when the processor 501 executes the program, the steps of the control method of the fuel cell system stack described in the first aspect are implemented.

[0099] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0100] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0101] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A module that specifies functions in one or more boxes.

[0102] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction module, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0104] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0105] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A control method for a fuel cell system, characterized in that: The fuel cell system includes a controller, an air subsystem and a hydrogen subsystem, the air subsystem includes a humidity control valve, the hydrogen subsystem includes a hydrogen pump and a drain valve, the controller is connected to the humidity control valve, the hydrogen pump and the drain valve respectively, and the method includes: Obtaining the hydrogen pump power of the hydrogen pump in a running state; Based on the hydrogen pump power and a preset hydrogen pump power reference value, determining the current humidity state of the fuel cell stack, wherein the humidity state reflects the flooding condition of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the normal humidity state of the fuel cell stack; If the humidity state is the first level humidity state, adjusting the opening of the humidity regulating valve; If the humidity state is the second level humidity state, the opening of the humidity regulating valve and the drainage time of the drainage valve are adjusted; The first-level humidity state includes an increased humidity state and an excessive humidity state, and the second-level humidity state includes a slight flooding state and a severe flooding state; the current humidity state of the fuel cell stack is determined based on the hydrogen pump power and a preset hydrogen pump power reference value, including: comparing the hydrogen pump power with the hydrogen pump power reference value; if it is determined that the hydrogen pump power is greater than the hydrogen pump power reference value and less than or equal to the first preset power, the hydrogen pump power is in periodic fluctuations, and the peak of the periodic fluctuation lasts for a cumulative period of more than a preset percentage within a single timing cycle, then it is determined that the fuel cell stack is in the increased humidity state, wherein the first preset power is greater than the hydrogen pump power reference value.

2. The control method according to claim 1, characterized in that: If it is determined that the hydrogen pump power is greater than or equal to the second preset power, it is determined that the fuel cell stack is in the excessive humidity state, and the second preset power is greater than the first preset power; If it is determined that the hydrogen pump power is greater than or equal to the third preset power, it is determined that the fuel cell stack is in the slightly flooded state, and the third preset power is greater than the second preset power; If it is determined that the hydrogen pump power is greater than or equal to the fourth preset power, it is determined that the fuel cell stack is in the severe flooding state, and the fourth preset power is greater than the third preset power.

3. The control method according to claim 1, characterized in that: If the humidity state is the first level humidity state, adjusting the opening of the humidity control valve includes: If the humidity state is a humidity increase state, reducing the opening of the humidity regulating valve by a first preset opening; If the humidity state is an over-humidity state, the opening of the humidity control valve is reduced by a second preset opening, and the first preset opening is smaller than the second preset opening.

4. The control method according to claim 3, characterized in that: If the humidity state is the second level humidity state, adjusting the opening of the humidity control valve and the drainage time of the drainage valve includes: If the humidity state is a slight flooding state, the opening of the humidity regulating valve is reduced by the second preset opening, and the drainage time of the drainage valve is increased by the first preset time; If the humidity state is a severe flooding state, the opening of the humidity regulating valve is reduced by a third preset opening, and the drainage time of the drain valve is increased by a second preset time, the second preset opening is smaller than the third preset opening, and the first preset time is smaller than the second preset time.

5. The control method according to claim 1, characterized in that: After adjusting the opening of the humidity control valve, the method further includes: The opening of the humidity control valve is restored to the initial opening, and after a preset waiting time, it is determined whether the battery stack is still in a normal operating state. If not, the adjusted opening of the humidity control valve is used as the initial opening.

6. The control method according to claim 1, characterized in that: After adjusting the opening of the humidity control valve and the drainage time of the drainage valve, the method further includes: The opening of the humidity controlling valve is restored to the initial opening and the drainage time of the drain valve is restored to the initial time, and after a preset waiting time, it is determined whether the battery stack is still in normal operation. If not, the opening of the humidity controlling valve after adjustment is used as the initial opening, and the drainage time of the drain valve after adjustment is used as the initial time.

7. A device for implementing the method according to any one of claims 1 to 6, characterized in that: include: An acquisition module, used to acquire the hydrogen pump power when the hydrogen pump is in operation; A humidity state determination module is used to determine the current humidity state of the fuel cell stack based on the hydrogen pump power and a preset hydrogen pump power reference value, wherein the humidity state reflects the flooding of the fuel cell stack, wherein the hydrogen pump power reference value is the hydrogen pump power corresponding to the humidity of the fuel cell stack being in a normal state; A first-stage regulating module, used for regulating the opening of the humidity regulating valve if the humidity state is the first-stage humidity state; A second-level regulating module, used for adjusting the opening of the humidity regulating valve and the drainage time of the drainage valve if the humidity state is the second-level humidity state; The first-level humidity state includes an increased humidity state and an excessive humidity state, and the second-level humidity state includes a slight flooding state and a severe flooding state; the current humidity state of the fuel cell stack is determined based on the hydrogen pump power and a preset hydrogen pump power reference value, including: comparing the hydrogen pump power with the hydrogen pump power reference value; if it is determined that the hydrogen pump power is greater than the hydrogen pump power reference value and less than or equal to the first preset power, the hydrogen pump power is in periodic fluctuations, and the peak of the periodic fluctuation lasts for a cumulative period of more than a preset percentage within a single timing cycle, then it is determined that the fuel cell stack is in the increased humidity state, wherein the first preset power is greater than the hydrogen pump power reference value.

8. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the method according to any one of claims 1 to 6 are implemented.

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