Fuel cell control method, system, device and computer readable storage medium

Abstract

The present invention discloses a fuel cell control method, system, device and computer-readable storage medium, the method comprising: obtaining the AC impedance of a fuel cell stack, determining the dry-wet state of the fuel cell stack according to the AC impedance; if the dry-wet state of the fuel cell stack is a flooded state, determining the flooded area of ​​the fuel cell stack; according to the flooded area, adjusting the speed of the hydrogen circulation pump to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state. Through the present invention, when fuel cell flooding occurs, flooding can be eliminated in a timely, efficient and accurate manner, thereby improving the service life and use efficiency of the fuel cell.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell technology, and in particular to a fuel cell control method, system, device and computer-readable storage medium. Background Art

[0002] Fuel cell vehicles have many advantages, such as short hydrogen refueling time, long driving range, and high fuel efficiency, and have become a new energy vehicle type that countries are focusing on developing. A fuel cell is a power generation system that converts chemical energy in a fuel into electrical energy. In the prior art, the two main types of fuel cells are proton exchange membrane fuel cells and solid oxide fuel cells. Among them, proton exchange membrane fuel cells use hydrogen as fuel and can convert chemical energy into electrical energy at a relatively low temperature. This type of fuel cell that uses hydrogen as fuel is called a hydrogen fuel cell.

[0003] The hydrogen fuel cell system includes a fuel cell stack as the main body, which is composed of hydrogen in the anode cavity and oxygen in the cathode cavity participating in the electrochemical reaction. According to the current stack structure, when the stack is loaded with fuel and fully reacts, a large amount of water vapor will be generated in the flow channel of the stack. The condensed water is not blown out in time by the high-pressure gas, but accumulates in the cathode flow channel. At the same time, it will penetrate into the anode flow channel through the exchange membrane and accumulate, resulting in water flooding inside the stack, which reduces the electrochemical conversion efficiency of the stack. In severe cases, it will cause irreversible damage to the proton exchange membrane in the stack. Summary of the invention

[0004] The main purpose of the present invention is to provide a fuel cell control method, system, device and computer-readable storage medium, aiming to solve the technical problem of reduced electrochemical conversion efficiency of the fuel cell stack due to water flooding inside the fuel cell stack.

[0005] To achieve the above object, the present invention provides a fuel cell control method, which is applied to a fuel cell system, wherein the fuel cell system includes a fuel cell stack and a hydrogen circulation pump connected to the fuel cell stack; the fuel cell control method includes the following steps:

[0006] Acquiring an AC impedance of a fuel cell stack, and determining a dry or wet state of the fuel cell stack according to the AC impedance;

[0007] If the dry-wet state of the fuel cell stack is a flooded state, determining a flooded area of ​​the fuel cell stack;

[0008] According to the flooded area, the rotation speed of the hydrogen circulation pump is adjusted to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state.

[0009] Optionally, the fuel cell system includes a DC-DC converter connected in series with the fuel cell stack; the AC impedance includes an ohmic impedance; and the step of obtaining the AC impedance of the fuel cell stack and determining the dry and wet state of the fuel cell stack according to the AC impedance includes:

[0010] Outputting a current disturbance signal of a preset frequency to the fuel cell stack through the DC-DC converter to obtain the ohmic impedance of the fuel cell stack based on feedback of the current disturbance signal;

[0011] Determining whether the ohmic impedance matches a preset flooding impedance interval;

[0012] If the ohmic impedance is within the range of the flooding impedance, it is determined that the dry-wet state of the fuel cell stack is a flooding state.

[0013] Optionally, the step of determining the flooded area of ​​the fuel cell stack comprises:

[0014] Obtaining an average voltage value of the fuel cell stack and a deviation from the mean corresponding to each cell in the fuel cell stack;

[0015] Determine a target mean difference that is greater than a preset voltage value among the mean differences, and determine a target battery stack single chip corresponding to the target mean difference;

[0016] According to the target fuel cell stack single chip, a flooded area of ​​the fuel cell stack is determined, and the flooded area includes a head and / or a tail of the fuel cell stack.

[0017] Optionally, the step of obtaining the average voltage value of the fuel cell stack and the deviation from the mean corresponding to each cell in the fuel cell stack includes:

[0018] Obtaining the voltage value and number of each cell in the fuel cell stack, and adding up the voltage values ​​to obtain the total voltage value of the fuel cell stack;

[0019] Calculating a quotient between the total voltage value and the number of cells, and using the quotient as an average voltage value of the fuel cell stack;

[0020] The differences between the average voltage value and each of the voltage values ​​are calculated, and the differences are used as the deviations from the mean corresponding to the single cell of the battery stack.

[0021] Optionally, the step of adjusting the rotation speed of the hydrogen circulation pump according to the flooded area so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state includes:

[0022] If the flooded area is the head of the fuel cell stack, the speed of the hydrogen circulation pump is reduced by a preset first speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state;

[0023] If the flooded area is the tail of the fuel cell stack, the rotation speed of the hydrogen circulation pump is increased by a preset second rotation speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state.

[0024] Optionally, the step of adjusting the rotation speed of the hydrogen circulation pump so that the dry-wet state of the fuel cell stack is in a dry-wet equilibrium state comprises:

[0025] Adjusting the rotation speed of the hydrogen circulation pump and acquiring the ohmic resistance in the AC impedance in real time, and determining whether the ohmic resistance matches a preset dry-wet balance impedance interval;

[0026] If the ohmic resistance matches the dry-wet balance impedance interval, the dry-wet state of the fuel cell stack is determined to be a dry-wet balance state, and the current rotation speed of the hydrogen circulation pump is maintained for a preset time.

[0027] Optionally, the fuel cell system includes stack cooling water, an exhaust valve and a drain valve; after the step of determining the dry and wet state of the fuel cell stack according to the AC impedance, the method further includes:

[0028] If the dry or wet state of the fuel cell stack is a flooded state, the current temperature of the stack cooling water is increased by a preset temperature value, and the pulse frequency of the exhaust valve and the pulse frequency of the drain valve are simultaneously increased by a preset frequency value.

[0029] In addition, to achieve the above-mentioned purpose, the present invention further provides a fuel cell control system, the fuel cell control system comprising:

[0030] A dryness and wetness detection module, used to obtain the AC impedance of the fuel cell stack, and determine the dryness and wetness state of the fuel cell stack according to the AC impedance;

[0031] A flooding identification module; if the dry and wet state of the fuel cell stack is a flooding state, determining the flooding area of ​​the fuel cell stack;

[0032] The operating condition adjustment module is used to adjust the rotation speed of the hydrogen circulation pump according to the flooded area so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state.

[0033] In addition, to achieve the above-mentioned purpose, the present invention also provides a fuel cell control device, including a processor, a memory, and a fuel cell control program stored in the memory and executable by the processor, wherein when the fuel cell control program is executed by the processor, the steps of the fuel cell control method as described above are implemented.

[0034] The present invention also provides a computer-readable storage medium, on which a fuel cell control program is stored, wherein when the fuel cell control program is executed by a processor, the steps of the fuel cell control method as described above are implemented.

[0035] The fuel cell control method in the technical solution of the present invention is applied to a fuel cell system through the steps, and the fuel cell system includes a fuel cell stack and a hydrogen circulation pump connected to the fuel cell stack; the fuel cell control method includes the following steps: obtaining the AC impedance of the fuel cell stack, and determining the dry and wet state of the fuel cell stack according to the AC impedance; if the dry and wet state of the fuel cell stack is a flooded state, determining the flooded area of ​​the fuel cell stack; according to the flooded area, adjusting the speed of the hydrogen circulation pump to make the dry and wet state of the fuel cell stack a dry and wet equilibrium state. The present invention solves the technical problem of reduced electrochemical conversion efficiency of the stack caused by flooding inside the stack.

[0036] In the existing technology, in order to deal with the flooding phenomenon of fuel cells, the humidity of the gas entering the fuel cell stack or the tail exhaust emission cycle is mainly adjusted according to the output current of the fuel cell stack system until the flooding phenomenon disappears. However, this method of regulating the fuel cell has low efficiency in eliminating the flooding phenomenon and the flooding phenomenon can only be partially eliminated. In the long run, the fuel cell is more likely to suffer greater damage than when no flooding occurs, resulting in a decrease in the electrochemical efficiency of the fuel cell stack.

[0037] The present invention mainly determines the wet and dry state of the fuel cell accurately through the AC impedance of the fuel cell, and further determines the flooding area where the flooding occurs when determining that the fuel cell is flooded, and can more accurately determine the specific position of the fuel cell stack where the flooding occurs, so as to adjust the rotation speed of the hydrogen circulation pump in a targeted manner according to the specific position where the flooding occurs, thereby achieving efficient, comprehensive and accurate elimination of the flooding phenomenon, avoiding damage to the fuel cell caused by the flooding phenomenon, and ensuring and improving the electrochemical conversion efficiency of the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the terminal structure of the hardware operating environment of the fuel cell control device involved in the embodiment of the present invention;

[0039] Figure 2 This is a schematic flow chart of a first embodiment of a fuel cell control method of the present invention;

[0040] Figure 3 This is a detailed flow chart of step S10 in the first embodiment of the fuel cell control method of the present invention;

[0041] Figure 4 A schematic flow chart of a second embodiment of a fuel cell control method according to the present invention;

[0042] Figure 5 A schematic diagram of the fuel cell system architecture involved in the fuel cell control method of the present invention;

[0043] Figure 6 A graph showing a polarization curve of a fuel cell stack with a current disturbance applied thereto in the fuel cell control method of the present invention;

[0044] Figure 7 A Nyquist curve diagram of a fuel cell involved in the fuel cell control method of the present invention;

[0045] Figure 8 A schematic diagram of a specific example of a fuel cell control method of the present invention;

[0046] Fig. 9 It is a schematic diagram of the framework structure of the fuel cell control system of the present invention.

[0047] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0049] Since the present invention is mainly a technical solution centered around the flooding phenomenon of fuel cells, in order to facilitate understanding of the various embodiments of the present invention, the flooding phenomenon discovered by the present invention and the reasons why the flooding phenomenon occurs at different positions of the fuel cell stack are first described:

[0050] During the operation of the fuel cell system, the voltage of several cells at the head or tail of the stack may be too low, which is called "single low". In severe cases, single low voltage of a cell may cause the fuel cell system to fail to operate or cause irreversible damage to the stack.

[0051] There are many reasons for the "single low" phenomenon of a single cell, one of the main reasons is that the stack is partially "flooded" during operation, especially the anode "flooding", which is more harmful. The anode "flooding" will cause the local gas flow channel of the stack to be blocked, liquid water will cover the surface of the catalyst, and hydrogen will not be able to react effectively with the catalyst, thus deteriorating the performance of the single cell, reducing the voltage, and corroding the catalyst.

[0052] An embodiment of the present invention provides a fuel cell control device.

[0053] like Figure 1 As shown, Figure 1 It is a structural schematic diagram of the hardware operating environment of the fuel cell control device involved in the embodiment of the present invention.

[0054] like Figure 1 As shown, the fuel cell control device may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display (Display), an input unit such as a control panel, and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WIFI interface). The memory 1005 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 1005 may optionally be a storage system independent of the aforementioned processor 1001. The memory 1005 as a computer storage medium may include a fuel cell control program.

[0055] Those skilled in the art will understand that Figure 1 The hardware structure shown in the figure does not constitute a limitation of the device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0056] Continue to refer to Figure 1 , Figure 1 The memory 1005 as a computer-readable storage medium may include an operating system, a user interface module, a network communication module, and a fuel cell control program.

[0057] exist Figure 1 In the embodiment, the network communication module is mainly used to connect to the server and perform data communication with the server; and the processor 1001 can call the fuel cell control program stored in the memory 1005 and execute the steps in the following embodiments.

[0058] Based on the hardware structure of the controller described above, various embodiments of the fuel cell control method of the present invention are proposed.

[0059] An embodiment of the present invention provides a fuel cell control method.

[0060] Please refer to Figure 2 , Figure 2 The flowchart of the first embodiment of the fuel cell control method of the present invention is shown in FIG. 1 ; in the first embodiment of the present invention, the fuel cell control method is applied to a fuel cell system, the fuel cell system includes a fuel cell stack and a hydrogen circulation pump connected to the fuel cell stack; the fuel cell control method includes the following steps:

[0061] Step S10, obtaining the AC impedance of the fuel cell stack, and determining the dry and wet state of the fuel cell stack according to the AC impedance;

[0062] In this embodiment, in order to facilitate understanding of the fuel cell system, reference can be made to Figure 5 , Figure 5 FIG. 1 is a schematic diagram of the fuel cell system architecture involved in the fuel cell control method of the present invention. Figure 5 As shown in the figure, the fuel cell system is electrically connected to the load, including the Fuel Cell Stacks and HRB (hydrogen circulation pump), and from left to right and from top to bottom, it also includes CVM (Cell voltage monitor, fuel cell single chip voltage inspection instrument), DC / DC Converter, WDV (drain valve), GPV (exhaust valve), LWS (water separator), PCV (proportional valve), SSV (hydrogen inlet valve), HFT (filter), HFM (flow meter), HPR (pressure reducing valve), HTK (hydrogen storage bottle), and the internal connection structure of the fuel cell system is:

[0063] The fuel cell single chip voltage inspection instrument is arranged on the fuel cell stack and is electrically connected to the fuel cell stack. The DC-DC converter is connected in series with the fuel cell stack, the fuel cell stack is connected to the water distributor through a pipeline and is close to the negative electrode side of the fuel cell stack, one end of the water distributor is connected to the drain valve through a pipeline, and the other end is connected to the inlet end of the hydrogen circulation pump through a pipeline, and the pipeline between the water distributor and the hydrogen circulation pump is also connected to the exhaust valve, one end of the proportional valve is connected to the outlet end of the hydrogen circulation pump through a pipeline, the other end of the proportional valve is connected to one end of the hydrogen inlet valve through a pipeline, the other end of the hydrogen inlet valve is connected to one end of the filter through a pipeline, the other end of the filter is connected to one end of the pressure reducing valve through a pipeline, and a flow meter is also arranged in the pipeline between the other end of the filter and one end of the pressure reducing valve, and one end of the pressure reducing valve is connected to the gas outlet end of the hydrogen storage bottle through a pipeline.

[0064] Based on the above fuel cell system, the AC impedance of the fuel cell stack is obtained, and the dry and wet state of the fuel cell stack is determined according to the AC impedance. The AC impedance may include one or a combination of ohmic impedance, anode activation impedance, cathode activation impedance, and mass transfer impedance.

[0065] The dry and wet states can be divided into: flooded state and dry and wet balanced state. Only in the dry and wet balanced state can the fuel cell ensure high performance release. In the flooded state, as the flooding becomes more and more serious, the fuel cell will be more and more seriously damaged, seriously affecting the performance of the fuel cell.

[0066] In addition, refer to Figure 5 In addition to the above-mentioned fuel cell system, the causes of anode flooding also need to be supplemented:

[0067] When the low-temperature dry new hydrogen from the hydrogen storage bottle meets the high-temperature and high-humidity anode waste hydrogen, a large amount of liquid water is condensed and carried into the fuel cell stack inlet in the mixed gas. The circulation of these anode residual hydrogen generally uses a hydrogen circulation pump, and the suction of the booster equipment will also bring the liquid water at the anode outlet of the fuel cell stack back to the inlet.

[0068] Especially in winter, low temperatures will cause more water vapor to condense. The liquid water accumulated at the anode entrance of the stack will easily flow into the first few cells at the anode end, blocking the gas flow channel, causing local "flooding" of the first few cells at the anode end and a drop in the cell voltage. At the same time, if the hydrogen flow into the stack is too large, liquid water will also be blown to the middle or tail of the stack with the hydrogen and gather. The difficulty of the fuel cell system lies in the estimation of the internal state of the stack, especially the estimation of the water state, which is similar to the estimation of the internal combustion state of a traditional internal combustion engine.

[0069] like Figure 3 As shown, in one embodiment, the fuel cell system includes a DC-DC converter connected in series with the fuel cell stack; the AC impedance includes an ohmic impedance; and the step S10 includes:

[0070] Step S11, outputting a current disturbance signal of a preset frequency to the fuel cell stack through the DC-DC converter to obtain the ohmic impedance of the fuel cell stack based on feedback of the current disturbance signal;

[0071] The EIS (alternating current impedance) function of the DC-DC converter is used to set and output a current disturbance signal of a preset frequency to the fuel cell stack, and the fuel cell stack can feedback its ohmic impedance η after receiving the current disturbance signal. ohmic , where the preset frequency can be 1000 Hz or other frequency values, which are not limited here.

[0072] As for the DC-DC converter outputting the current disturbance signal of the preset frequency, the fuel cell stack can be fed back based on the ohmic impedance of the current disturbance signal. The principle can be referred to Figure 6 ,like Figure 6 As shown:

[0073] The horizontal axis represents the DC current, and the vertical axis represents the battery voltage of the fuel cell. A small current disturbance (small signal current response) is applied to the DC current, thereby generating a small voltage disturbance (small signal voltage perturbation), and thus obtaining the corresponding impedance information. The pseudo-linear part of the jV curve refers to the stack polarization curve. Pseudo-linearity refers to a non-proportional, non-linear relationship, and the first-order derivative is not a constant.

[0074] Step S12, determining whether the ohmic impedance matches a preset flooding impedance interval;

[0075] Step S13: If the ohmic impedance is within the water flooding impedance interval, it is determined that the dry-wet state of the fuel cell stack is a water flooding state.

[0076] By comparing and matching the acquired ohmic impedance with the preset flooding impedance interval, if it is in this interval, it is considered to match the preset flooding impedance interval, thereby determining that the dry-wet state of the fuel cell stack is a flooded state. Otherwise, it does not match, and the dry-wet state of the fuel cell stack is determined to be a dry-wet equilibrium state. In addition, the ohmic impedance can also be compared with a preset database under the dry-wet equilibrium state of the stack, so as to analyze whether the anode of the stack is in a flooded state. The flooding impedance interval can be set according to the specifications of different fuel cells, and is not limited here.

[0077] In addition, it is necessary to further explain that the reason why this embodiment uses ohmic impedance can be seen in Figure 7 .like Figure 7 As shown,

[0078] The horizontal axis is the real part of the total impedance, and the vertical axis is the imaginary part of the total impedance. Ω Represents the stack resistance, Z fA The Faraday impedance of the stack anode, Z fC The Faraday impedance of the cathode of the battery stack. Ω The interval is η ohmic , that is, ohmic resistance, that is, ohmic loss. Ω , Z Ω +Z fA ), is η act , A Represents the anode activation loss, that is, the anode activation impedance. Ω +Z fA , Z Ω +ZfA +Z fC ) represents the cathode activation loss, that is, the cathode activation impedance.

[0079] Reference Figure 7 The corresponding relationship between the impedance information and the principle of the fuel cell system is ohmic impedance, anode activation impedance, cathode activation impedance, and mass transfer impedance. If the applied small current signal (current disturbance signal) is high frequency, only ohmic impedance will be obtained, and ohmic impedance corresponds to the dry and wet state of the membrane.

[0080] In one embodiment, the fuel cell system includes a stack cooling water and exhaust valve and a drain valve; after the step of determining the dry and wet state of the fuel cell stack according to the AC impedance, the method further includes:

[0081] If the dry or wet state of the fuel cell stack is a flooded state, the current temperature of the stack cooling water is increased by a preset temperature value, and the pulse frequency of the exhaust valve and the pulse frequency of the drain valve are simultaneously increased by a preset frequency value.

[0082] For example, if the dry and wet state of the fuel cell stack is a flooded state, the current temperature of the stack cooling water can be increased by 2°C, and the pulse switching frequency of the drain valve WDV and the exhaust valve GPV can be increased by 500ms. Of course, the preset temperature value and the preset frequency value can also be set to other values ​​according to actual needs, which are not limited here. In this embodiment, by increasing the stack cooling water and the pulse switching frequency of the drain valve and the exhaust valve, the condensed water can be removed in a timely and efficient manner, and the damage to the fuel cell from the beginning of the flooding can be avoided as much as possible.

[0083] Step S20, if the dry / wet state of the fuel cell stack is a flooded state, determining a flooded area of ​​the fuel cell stack;

[0084] If the dry and wet state of the fuel cell stack is a flooded state, the flooded area of ​​the fuel cell stack is determined, and the flooded area includes the head and / or tail of the fuel cell stack, specifically, a first stack monolithic set of a preset number of the head of the fuel cell stack and a second stack monolithic set of a preset number of the tail of the fuel cell stack. In addition, the fuel cell stack can also be divided into the head and / or tail equally. Assuming that the number of fuel cell stack monolithic chips is 40, the first 20 monolithic chips are the head of the fuel cell stack, and the last 20 monolithic chips are the tail of the fuel cell stack.

[0085] Step S30, adjusting the rotation speed of the hydrogen circulation pump according to the flooded area so that the dry-wet state of the fuel cell stack is in a dry-wet equilibrium state.

[0086] Depending on whether the flooded area is the head or the tail of the fuel cell stack, the rotation speed of the hydrogen circulation pump is regulated differently so that the dry-wet state of the fuel cell stack is in a dry-wet equilibrium state.

[0087] In addition, after the fuel cell stack enters the dry-wet equilibrium state, control parameters such as the target temperature of the fuel cell stack cooling water, the pulse switching frequency of the drain valve WDV, the exhaust valve GPV, and the speed of the hydrogen circulation pump are restored to the preset calibration values.

[0088] In one embodiment, step S30 includes:

[0089] Step a, if the flooded area is the head of the fuel cell stack, reducing the speed of the hydrogen circulation pump by a preset first speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state;

[0090] Step b: if the flooded area is the tail of the fuel cell stack, the speed of the hydrogen circulation pump is increased by a preset second speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state.

[0091] If the flooded area is the head of the fuel cell stack, the current speed of the hydrogen circulation pump needs to be reduced by a certain speed. For example, if the current speed is 6200 rpm, the current speed can be gradually reduced to 1200 rpm to obtain 5000 rpm.

[0092] If the flooded area is the tail of the fuel cell stack, the current speed of the hydrogen circulation pump needs to be increased by a certain amount. For example, if the current speed is 5800 rpm, the current speed can be gradually increased to 1500 rpm to obtain 7300 rpm.

[0093] Through this embodiment, different speed controls can be set for the hydrogen circulation pump according to different flooded areas. When the flooded area is the head, the proportion of waste hydrogen usage is reduced by reducing the speed, thereby eliminating the flooding phenomenon at the head. When the flooded area is the tail, the proportion of waste hydrogen usage is increased by increasing the speed, thereby eliminating the flooding phenomenon at the tail.

[0094] In another embodiment, the step of adjusting the rotation speed of the hydrogen circulation pump in step S30 so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state includes:

[0095] Step c, adjusting the rotation speed of the hydrogen circulation pump and obtaining the ohmic resistance in the AC impedance in real time, and determining whether the ohmic resistance matches a preset dry-wet equilibrium impedance interval;

[0096] Step d: if the ohmic resistance matches the dry-wet balance impedance interval, the dry-wet state of the fuel cell stack is determined to be a dry-wet balance state, and the current speed of the hydrogen circulation pump is maintained for a preset time.

[0097] In this embodiment, in the process of adjusting the speed of the hydrogen circulation pump, it is necessary to obtain the ohmic resistance of the fuel cell stack in real time and determine whether the ohmic resistance matches the preset dry-wet balance impedance interval. If it matches, it is considered that the dry-wet state of the fuel cell stack has changed from the flooded state to the dry-wet balance state, and the current speed of the hydrogen circulation pump is maintained for a preset time to ensure the stability of the hydrogen circulation pump and the fuel cell system. The dry-wet balance impedance interval and the preset time can be set according to actual needs and are not limited here.

[0098] In addition, in one embodiment, the step of adjusting the rotation speed of the hydrogen circulation pump in step S30 so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state includes:

[0099] Adjusting the rotation speed of the hydrogen circulation pump and obtaining in real time whether the maximum deviation from the mean of the voltage of a single cell in the fuel cell stack is less than a second preset voltage value;

[0100] If the maximum deviation from the mean is less than the second preset voltage value, the dry-wet state of the fuel cell stack is determined to be a dry-wet equilibrium state, and the current speed of the hydrogen circulation pump is maintained for a preset time.

[0101] The second preset voltage value is different from the above preset voltage value, and the second preset voltage value can be set according to actual needs, such as 30mV.

[0102] The present invention mainly determines the wet and dry state of the fuel cell accurately through the AC impedance of the fuel cell, and further determines the flooding area where the flooding occurs when determining that the fuel cell is flooded, and can more accurately determine the specific position of the fuel cell stack where the flooding occurs, so as to adjust the rotation speed of the hydrogen circulation pump in a targeted manner according to the specific position where the flooding occurs, thereby achieving efficient, comprehensive and accurate elimination of the flooding phenomenon, avoiding damage to the fuel cell caused by the flooding phenomenon, and ensuring and improving the electrochemical conversion efficiency of the fuel cell stack.

[0103] Please refer to Figure 4 , Figure 4 The figure is a flow chart of the second embodiment of the fuel cell control method of the present invention; further, based on the first embodiment of the fuel cell control method of the present invention, the second embodiment of the fuel cell control method of the present invention is proposed. In this embodiment, the step S20 includes:

[0104] Step S21, obtaining an average voltage value of the fuel cell stack and a deviation from the mean corresponding to each cell in the fuel cell stack;

[0105] The average voltage value of the fuel cell stack can be obtained by obtaining the entire voltage value of the fuel cell stack and dividing the entire voltage value by the number of cells in the stack. Alternatively, the total voltage of the fuel cell stack can be obtained by obtaining the voltage values ​​of each cell in the stack and then adding them together to obtain the average voltage value. After determining the average voltage value, the deviation from the mean corresponding to each cell in the stack is obtained.

[0106] In one embodiment, the step S21 includes:

[0107] Step e, obtaining the voltage value and number of each cell in the fuel cell stack, and superimposing each of the voltage values ​​to obtain the total voltage value of the fuel cell stack;

[0108] Step f, calculating a quotient between the total voltage value and the number of cells, and using the quotient as an average voltage value of the fuel cell stack;

[0109] Step g, calculating the differences between the average voltage value and each of the voltage values, and using the differences as the deviations from the mean corresponding to the single cell of the battery stack.

[0110] In this embodiment, the total voltage of the fuel cell stack is obtained by obtaining the voltage values ​​of each cell stack and then adding them up, and then the average voltage value is obtained. Specifically, the fuel cell control system also includes an FCU (fuel cell control unit), which detects and reports the voltage values ​​of each cell stack in a cycle of 10ms through a fuel cell cell voltage patrol meter, reports them to the fuel cell control unit, and adds up each of the voltage values ​​to obtain the total voltage value of the fuel cell stack, and then calculates the quotient between the total voltage value and the number of cells, and uses the quotient as the average voltage value of the fuel cell stack, and then calculates each difference between the average voltage value and each of the voltage values, and then obtains the deviation from the mean corresponding to each cell stack.

[0111] The above calculation process can be expressed as follows:

[0112] Average voltage Vn is the battery voltage of each cell in the stack, n is the total number of cells in the stack, and the average voltage difference of the cell in the stack is V dev (V dev =V ave -V n ).

[0113] Through this embodiment, the average voltage value can be determined more accurately, and thus the flooded area where the flooding phenomenon occurs can be accurately determined.

[0114] Step S22, determining a target mean difference greater than a preset voltage value among the mean differences, and determining a target battery stack single chip corresponding to the target mean difference;

[0115] Step S23, determining a flooded area of ​​the fuel cell stack according to the target stack single chip, wherein the flooded area includes a head and / or a tail of the fuel cell stack.

[0116] If each of the deviations from the mean has a target deviation from the mean greater than a preset voltage value, then the target stack single chip corresponding to the target deviation from the mean is determined, and then the position of the target stack single chip in the fuel cell stack is determined. The preset voltage value can be set according to actual needs.

[0117] For example, in one example: FCU calculates the average voltage V based on the battery stack single chip voltage information reported by CVM ave , the voltage difference between each chip is V dev , if the V of the first 15 cells in the stack dev If the maximum value is greater than 50mV, it means that the front of the battery stack is flooded. If the V dev If the maximum value is greater than 50mV, it means that the tail of the battery stack is flooded.

[0118] Through the above second embodiment, the flooding area of ​​the fuel cell, that is, the flooding location, can be accurately determined, and then the working conditions of the fuel cell system can be adjusted specifically to accurately eliminate the flooding phenomenon in the fuel cell, thereby improving the service life and use efficiency of the fuel cell.

[0119] To further understand the above embodiments of the present invention, please refer to Figure 8 , Figure 8 The figure is a schematic diagram of a specific example of the fuel cell control method of the present invention. The overall process of the present invention in an actual application scenario can be:

[0120] Set the EIS current disturbance frequency to 1000HZ to monitor the ohmic impedance of the stack. The FCU compares the current ohmic impedance with the preset database under the dry-wet equilibrium state of the stack to determine whether the stack is flooded.

[0121] If it is not in a flooded state, the control parameters such as the target temperature of the stack cooling water, the pulse switching frequency of the drain valve WDV, the exhaust valve GPV, and the speed of the hydrogen circulation pump are restored to the calibrated values;

[0122] If the battery is flooded, the target temperature of the stack cooling water is adjusted 2°C higher than the original calibration parameter, and the pulse switching frequency of the drain valve WDV and the exhaust valve GPV is adjusted faster by 500ms.

[0123] The FCU calculates the average voltage and the average voltage deviation of each cell based on the cell voltage information reported by the CVM.

[0124] The maximum value of the current 15-cell voltage deviation from the average is greater than 50mV, confirming that the front part of the stack is flooded, and the speed of the hydrogen circulation pump is reduced by 1200rpm;

[0125] When the maximum value of the voltage difference of the 15 tail cells is greater than 50mV, it is confirmed that the tail of the stack is flooded, and the speed of the hydrogen circulation pump is increased by 1500rpm;

[0126] Continue to operate for 3 minutes according to the current operating conditions of the fuel cell system;

[0127] Determine whether the ohmic impedance returns to the preset dry-wet balance value, or determine whether the maximum single-chip voltage is less than 30mV;

[0128] If one of the above conditions is met, control parameters such as the target temperature of the stack cooling water, the pulse switching frequency of the drain valve WDV, the exhaust valve GPV, and the speed of the hydrogen circulation pump are restored to the preset calibration values.

[0129] In addition, refer to Fig. 9 The present invention further provides a fuel cell control system, the fuel cell control system comprising:

[0130] A dryness and wetness detection module A10 is used to obtain the AC impedance of the fuel cell stack and determine the dryness and wetness state of the fuel cell stack according to the AC impedance;

[0131] A flooding identification module A20, if the dry and wet state of the fuel cell stack is a flooding state, determines a flooding area of ​​the fuel cell stack;

[0132] The operating condition adjustment module A30 is used to adjust the rotation speed of the hydrogen circulation pump according to the flooded area so that the dry-wet state of the fuel cell stack is in a dry-wet equilibrium state.

[0133] Optionally, the dryness and wetness detection module A10 is further used for:

[0134] Outputting a current disturbance signal of a preset frequency to the fuel cell stack through the DC-DC converter to obtain the ohmic impedance of the fuel cell stack based on feedback of the current disturbance signal;

[0135] Determining whether the ohmic impedance matches a preset flooding impedance interval;

[0136] If the ohmic impedance is within the range of the flooding impedance, it is determined that the dry-wet state of the fuel cell stack is a flooding state.

[0137] Optionally, the flooding identification module A20 is further used to:

[0138] Obtaining an average voltage value of the fuel cell stack and a deviation from the mean corresponding to each cell in the fuel cell stack;

[0139] Determine a target mean difference that is greater than a preset voltage value among the mean differences, and determine a target battery stack single chip corresponding to the target mean difference;

[0140] According to the target fuel cell stack single chip, a flooded area of ​​the fuel cell stack is determined, and the flooded area includes a head and / or a tail of the fuel cell stack.

[0141] Optionally, the flooding identification module A20 is further used to:

[0142] Obtaining the voltage value and number of each cell in the fuel cell stack, and adding up the voltage values ​​to obtain the total voltage value of the fuel cell stack;

[0143] Calculating a quotient between the total voltage value and the number of cells, and using the quotient as an average voltage value of the fuel cell stack;

[0144] The differences between the average voltage value and each of the voltage values ​​are calculated, and the differences are used as the deviations from the mean corresponding to the single cell of the battery stack.

[0145] Optionally, the flooding identification module A20 is further used to:

[0146] If the flooded area is the head of the fuel cell stack, the speed of the hydrogen circulation pump is reduced by a preset first speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state;

[0147] If the flooded area is the tail of the fuel cell stack, the rotation speed of the hydrogen circulation pump is increased by a preset second rotation speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state.

[0148] Optionally, the operating condition adjustment module A30 is further used for:

[0149] Adjusting the rotation speed of the hydrogen circulation pump and acquiring the ohmic resistance in the AC impedance in real time, and determining whether the ohmic resistance matches a preset dry-wet balance impedance interval;

[0150] If the ohmic resistance matches the dry-wet balance impedance interval, the dry-wet state of the fuel cell stack is determined to be a dry-wet balance state, and the current rotation speed of the hydrogen circulation pump is maintained for a preset time.

[0151] Optionally, the operating condition adjustment module A30 is further used for:

[0152] If the dry or wet state of the fuel cell stack is a flooded state, the current temperature of the stack cooling water is increased by a preset temperature value, and the pulse frequency of the exhaust valve and the pulse frequency of the drain valve are simultaneously increased by a preset frequency value.

[0153] The specific implementation of the fuel cell control system of the present invention is basically the same as the above-mentioned embodiments of the fuel cell control method, and will not be repeated here.

[0154] In addition, the present invention also provides a computer-readable storage medium. The computer-readable storage medium of the present invention stores a fuel cell control program, wherein when the fuel cell control program is executed by a processor, the steps of the fuel cell control method described above are implemented.

[0155] The method implemented when the fuel cell control program is executed can refer to the various embodiments of the fuel cell control method of the present invention, and will not be described in detail here.

[0156] Those skilled in the art will appreciate 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. Moreover, 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.

[0157] 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 system that specifies the functions of a box or boxes.

[0158] 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 product including an instruction system, 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.

[0159] 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.

[0160] It should be noted that in the claims, any reference signs placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The present invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several systems, several of these systems may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0161] 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.

[0162] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A fuel cell control method, characterized in that: The fuel cell control method is applied to a fuel cell system, wherein the fuel cell system comprises a fuel cell stack and a hydrogen circulation pump connected to the fuel cell stack; the fuel cell control method comprises the following steps: Acquiring an AC impedance of a fuel cell stack, and determining a dry or wet state of the fuel cell stack according to the AC impedance; If the dry-wet state of the fuel cell stack is a flooded state, determining a flooded area of ​​the fuel cell stack; According to the flooded area, adjusting the rotation speed of the hydrogen circulation pump to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state; The step of determining the flooded area of ​​the fuel cell stack comprises: Obtaining the voltage value and number of each cell in the fuel cell stack, and adding up the voltage values ​​to obtain the total voltage value of the fuel cell stack; Calculating a quotient between the total voltage value and the number of cells, and using the quotient as an average voltage value of the fuel cell stack; Calculating each difference between the average voltage value and each of the voltage values, and using the difference as the deviation from the mean corresponding to the battery stack single chip; Determine a target mean difference that is greater than a preset voltage value among the mean differences, and determine a target battery stack single chip corresponding to the target mean difference; According to the target stack monolithic chip, a flooded area of ​​the fuel cell stack is determined, wherein the flooded area includes a head and / or a tail of the fuel cell stack; wherein the head of the fuel cell stack includes a set of a preset number of first stack monolithic chips at the head of the fuel cell stack, and the tail of the fuel cell stack includes a set of a preset number of second stack monolithic chips at the tail of the fuel cell stack; The step of adjusting the rotation speed of the hydrogen circulation pump according to the flooded area to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state comprises: If the flooded area is the head of the fuel cell stack, the speed of the hydrogen circulation pump is reduced by a preset first speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state; If the flooded area is the tail of the fuel cell stack, the rotation speed of the hydrogen circulation pump is increased by a preset second rotation speed value to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state.

2. The fuel cell control method according to claim 1, characterized in that: The fuel cell system includes a DC-DC converter connected in series with the fuel cell stack; The AC impedance includes ohmic impedance; the step of obtaining the AC impedance of the fuel cell stack and determining the dry and wet state of the fuel cell stack according to the AC impedance includes: Outputting a current disturbance signal of a preset frequency to the fuel cell stack through the DC-DC converter to obtain the ohmic impedance of the fuel cell stack based on feedback of the current disturbance signal; Determining whether the ohmic impedance matches a preset flooding impedance interval; If the ohmic impedance is within the range of the flooding impedance, it is determined that the dry-wet state of the fuel cell stack is a flooding state.

3. The fuel cell control method according to claim 1, characterized in that: The step of adjusting the rotation speed of the hydrogen circulation pump to make the dry-wet state of the fuel cell stack a dry-wet equilibrium state includes: Adjusting the rotation speed of the hydrogen circulation pump and acquiring the ohmic resistance in the AC impedance in real time to determine whether the ohmic resistance matches a preset dry-wet balance impedance interval; If the ohmic resistance matches the dry-wet balance impedance interval, the dry-wet state of the fuel cell stack is determined to be a dry-wet balance state, and the current rotation speed of the hydrogen circulation pump is maintained for a preset time.

4. The fuel cell control method according to claim 1, characterized in that: The fuel cell system includes a stack cooling water, an exhaust valve and a drain valve; after the step of determining the dry and wet state of the fuel cell stack according to the AC impedance, the method further includes: If the dry or wet state of the fuel cell stack is a flooded state, the current temperature of the stack cooling water is increased by a preset temperature value, and the pulse frequency of the exhaust valve and the pulse frequency of the drain valve are simultaneously increased by a preset frequency value.

5. A fuel cell control system, characterized in that: The fuel cell control system comprises: A dryness and wetness detection module, used to obtain the AC impedance of the fuel cell stack, and determine the dryness and wetness state of the fuel cell stack according to the AC impedance; A flooding identification module; if the dry and wet state of the fuel cell stack is a flooding state, the flooding area of ​​the fuel cell stack is determined; the flooding identification module is also used to obtain the voltage value and the number of each chip in the fuel cell stack, and superimpose each of the voltage values ​​to obtain the total voltage value of the fuel cell stack; calculate the quotient between the total voltage value and the number of chips, and use the quotient as the average voltage value of the fuel cell stack; calculate each difference between the average voltage value and each of the voltage values, and use the difference as the deviation from the mean corresponding to the stack chip; determine a target deviation from the mean that is greater than a preset voltage value among each deviation from the mean, and determine a target stack chip corresponding to the target deviation from the mean; according to the target stack The monolithic chip is used to determine the flooded area of ​​the fuel cell stack, the flooded area includes the head and / or tail of the fuel cell stack, wherein the head of the fuel cell stack includes a preset number of first stack monolithic chip sets at the head of the fuel cell stack, and the tail of the fuel cell stack includes a preset number of second stack monolithic chip sets at the tail of the fuel cell stack; the flooding identification module is also used to reduce the speed of the hydrogen circulation pump by a preset first speed value if the flooded area is the head of the fuel cell stack so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state; if the flooded area is the tail of the fuel cell stack, increase the speed of the hydrogen circulation pump by a preset second speed value so that the dry-wet state of the fuel cell stack is a dry-wet equilibrium state; The operating condition adjustment module is used to adjust the rotation speed of the hydrogen circulation pump according to the flooded area until the dry-wet state of the fuel cell stack is in a dry-wet equilibrium state.

6. A fuel cell control device, characterized in that: The fuel cell control device includes a processor, a memory, and a fuel cell control program stored in the memory and executable by the processor, wherein when the fuel cell control program is executed by the processor, the steps of the fuel cell control method as described in any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a fuel cell control program, wherein when the fuel cell control program is executed by a processor, the steps of the fuel cell control method according to any one of claims 1 to 4 are implemented.

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