Fuel cell single-low control method and system, computer equipment and storage medium

Abstract

The invention relates to the technical field of fuel cells, and discloses a fuel cell single-low control method and system, computer equipment and a storage medium, and the method comprises the following steps: obtaining voltages of all cells in a stack, and determining whether the cells in the stack are in a single-low state according to an average value of the voltages of all the cells; if the batteries are in the single low state, the nitrogen concentration in the electric pile and the wetting uniformity of all the batteries are obtained respectively, and a first control mode and / or a second control mode are / is selected to adjust the batteries in the electric pile; wherein the first control mode is used for adjusting the nitrogen concentration in the galvanic pile based on the exhaust frequency; according to the method and the device, the reasons of single low occurrence of the battery can be effectively identified, and the proper control mode is selected according to different single low reasons to accurately regulate and control the battery, so that the battery can be quickly separated from the single low state, and the battery wettability uniformity in the electric pile is improved. And the control method can be suitable for a complex and changeable environment.

Description

Technical Field

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

[0002] Proton exchange membrane (PEM) plays a basic role in separating the reaction gases on the cathode and anode sides of the fuel cell. However, the proton exchange membrane cannot completely prevent the transmission of gases. During the operation of the fuel cell, nitrogen and other gas impurities in the air on the cathode side will gradually penetrate into the anode side. As the working time increases, nitrogen and other impurity gases gradually accumulate in the anode circulation system, diluting the hydrogen fuel gas. If the nitrogen concentration increases to above a certain percentage, such as 50%, it will seriously affect the operation of the fuel cell stack (a single low state occurs). The commonly used solution is to set an exhaust valve in the anode circulation loop of the fuel cell stack, and use a fixed frequency to open the exhaust valve to discharge nitrogen and other impurity gases from the anode side. The problem with the existing technology is that the processing method is single, lacks automatic adjustment capability, and is not suitable for complex working conditions and changing environments.

[0003] Furthermore, due to the complex driving conditions of the vehicle, long-term high-power driving or long-term low-power driving may cause the proton exchange membrane in the fuel cell to become flooded or dry, resulting in a significant reduction in the proton transfer efficiency of the proton exchange membrane and a single low state. The commonly used solution is to increase or decrease the air flow rate to achieve different degrees of purging of the battery stack cathode to alleviate the flooding or drying of the proton exchange membrane. The problem with the existing technology is also that the processing method is single and the efficiency is low, and the state of the proton exchange membrane cannot be effectively changed for different forms of environment. Summary of the invention

[0004] The present invention aims to solve the above-mentioned problems and provides a fuel cell single low control method, system, computer device and storage medium to solve the problem that the existing fuel cell cannot promptly and effectively solve the single low state when the single low state occurs.

[0005] To achieve this object, the present invention adopts the following technical solutions: A fuel cell single low control method comprises the following steps: Obtain the voltage of all batteries in the battery stack, and determine whether the battery in the battery stack is in a single low state based on the average voltage of all batteries; If the battery is in a single low state, the nitrogen concentration in the battery stack and the wetting uniformity of all batteries are obtained respectively, and the first control mode and / or the second control mode are selected to adjust the batteries in the battery stack; Among them, the first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency; The second control mode adjusts the wetting uniformity of the cells in the stack based on the operating parameters.

[0006] Preferably, the first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency, comprising the following steps: Setting a first pressure difference threshold; Obtain the open-loop exhaust frequency based on the current stack current; The average voltage values ​​ΔU1 and ΔU2 of the stack before and after the first exhaust of the exhaust valve are obtained respectively, and the absolute difference between ΔU1 and ΔU2 is calculated and recorded as variable ΔU3; If the variable ΔU3 is greater than the first pressure difference threshold, the variable of the open-loop exhaust frequency is increased based on the nitrogen concentration to reduce the nitrogen concentration in the fuel cell stack.

[0007] Preferably, increasing the variable of the open-loop exhaust frequency based on the nitrogen concentration includes the following control steps: Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals; Each interval corresponds to a different exhaust frequency, and the absolute increments of the exhaust frequencies corresponding to adjacent intervals are consistent, all Δf; The nitrogen concentration is directly proportional to the exhaust frequency. The higher the nitrogen concentration, the greater the variable of increasing the open-loop exhaust frequency based on the nitrogen concentration.

[0008] Preferably, the wetting uniformity of the battery in the battery stack includes the following judging steps: Setting a second pressure difference threshold and a third pressure difference threshold; Obtain the highest voltage and the lowest voltage of all batteries in the battery stack, and calculate the absolute difference between the highest voltage and the lowest voltage, which is recorded as U4; Calculate the absolute differences between the highest voltage and the lowest voltage and the average voltage, respectively, and record them as ΔU5 and ΔU6; When and only when U4 is greater than the second pressure difference threshold, and U5 and ΔU6 are both greater than the third pressure difference threshold, it is determined that the wetting uniformity of the batteries in the battery stack is poor.

[0009] Preferably, the second control mode adjusts the wetting uniformity of the batteries in the battery stack based on the operating parameters, comprising the following steps: Obtain the current battery stack current and determine the vehicle's operating status based on the current obtained; Determine the wetting status of the battery in the battery stack according to the operating status of the vehicle; The wet state of the battery includes a flooded state and a dry state.

[0010] Preferably, if the battery is in a flooded state, the following control steps are included: Increase the speed of the hydrogen circulation pump to increase the hydrogen flow at the cathode inlet of the fuel cell stack; Increase the opening of the proportional valve to increase the hydrogen pressure at the cathode inlet of the fuel cell stack; Increase the speed of the air compressor to increase the air flow at the anode inlet of the stack; Increase the temperature of the cooling circulating fluid, reduce the temperature difference between the cooling circulating fluid and the fuel cell stack, and increase the evaporation rate of water on the proton exchange membrane.

[0011] Preferably, if the battery is in a dry state, the following control steps are included: Reduce drainage frequency and increase the humidity of circulating hydrogen; Increase the residence time of the air in the humidifier to increase the humidity of the air entering the cathode of the fuel cell stack; Lower the temperature of the cooling circulating fluid, increase the temperature difference between the cooling circulating fluid and the fuel cell stack, and slow down the evaporation rate of water on the proton exchange membrane.

[0012] Preferably, based on the aging degree of the exhaust valve, a third control mode is further included, wherein the third control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust time; The third control mode comprises the following steps: Obtain the open-loop exhaust duration based on the current stack current; Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals; Each interval corresponds to a different exhaust time, and the absolute increments of the exhaust time corresponding to adjacent intervals are consistent, both ΔT; The nitrogen concentration is directly proportional to the exhaust time. The higher the nitrogen concentration, the greater the variable of the open-loop exhaust time based on the nitrogen concentration.

[0013] A fuel cell single low control system, the fuel cell single low control system is used to implement the above control method, including: The parameter module is used to obtain various operating parameters in the battery stack and calculate the judgment data through the obtained parameters; A judgment module, used to receive various judgment data from the parameter module, and identify the state of the battery in the fuel cell through the received various judgment data; A selection module, used for selecting an adaptive control mode for a fuel cell in an abnormal state; The regulating module is used to receive the signal from the selecting module and adjust various operating parameters in the fuel cell stack so that the fuel cell stack returns to normal working state.

[0014] A computer device comprising: Memory and processor; The memory is used to store at least one program; When the program is executed by a processor, the processor implements the control method as described in any one of claims 1-8.

[0015] A storage medium includes a computer program, and the computer program implements the above control method when executed by a processor.

[0016] The contribution of the present invention is that the present invention can effectively identify the cause of single low battery, and select appropriate control modes (first control mode and second control mode) according to different single low causes to precisely regulate the battery, so that the battery can be out of the single low state while maintaining a stable internal environment, and the control method of the present invention can be applicable to complex and changeable environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the fuel cell low control method of the present invention; Figure 2 It is a flow chart of regulating and controlling the nitrogen concentration in the fuel cell stack based on the exhaust frequency in the first control mode of the present invention; Figure 3 is a schematic diagram of a control method when a battery is in a flooded state in the second control mode of the present invention; Figure 4 is a schematic diagram of a control method when the battery is in a dry state in the second control mode of the present invention; Figure 5 It is a flow chart of regulating and controlling the nitrogen concentration in the fuel cell stack based on the exhaust valve aging degree and the exhaust frequency in the third control mode of the present invention; Figure 6 is a schematic diagram of the structure of a control system in one embodiment of the present invention; Figure 7 It is a structural schematic diagram of the computer device and storage medium in the present invention. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The drawings provide embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing the embodiments of the present invention and are not intended to limit this application.

[0020] It is understood that the terms "first", "second", etc. used in this application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is a transmission of electrical signals or data between the connected objects.

[0021] When used herein, the singular forms "a", "a person" and "the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0022] like Figure 1 As shown, a fuel cell single low control method comprises the following steps: Obtain the voltage of all batteries in the battery stack, and determine whether the battery in the battery stack is in a single low state based on the average voltage of all batteries; Specifically, determining whether a battery in the battery stack is in a single low state includes the following steps: Set the interval time Δt (1s) and the voltage difference warning value (90mV); At time t1, the average voltage of all batteries in the battery stack is obtained, which is recorded as U(t1); At time t1+Δt, the average voltage of all batteries in the battery stack is obtained, which is recorded as U(t2); Compare the absolute difference between U(t1) and U(t2) with the voltage difference warning value. If the absolute difference between U(t1) and U(t2) is greater than the voltage difference warning value, it is determined that the battery in the stack is in a single low state. If the battery is in a single low state, the nitrogen concentration in the battery stack and the wetting uniformity of all batteries are obtained respectively, and the first control mode and / or the second control mode are selected to adjust the batteries in the battery stack; Further explanation: the battery in the battery stack is in a single low state mainly including the following two situations: The first situation is that the nitrogen concentration in the anode chamber of the fuel cell stack is too high, exceeding the specified threshold (50%), diluting the hydrogen in the anode of the fuel cell stack, resulting in reduced efficiency of the proton exchange membrane in the battery and reduced power generation, thus presenting a single low state.

[0023] The second situation is that the proton exchange membrane in the battery is not in a good wetting state, and the proton exchange membrane is in a polarized state, causing the proton exchange membrane to be too wet (flooded state) or too dry (dry state), thereby affecting the proton transmission of the protons by the proton exchange membrane, affecting the power generation performance, and the battery is in a single low state.

[0024] If you need to solve the single-low state of the battery, you first need to clarify the cause of the single-low state. Therefore, you need to obtain the nitrogen concentration in the battery stack and the wetting uniformity of all batteries respectively. Use the above two indicators to judge the specific cause of the single-low state of the battery. After determining the cause of the single-low state, select the appropriate control mode to alleviate the single-low state until the battery returns to normal working state.

[0025] Further explanation: due to the complex operating conditions of the fuel cell system, it is possible that the nitrogen concentration exceeds the standard and the battery wetting uniformity is poor at the same time. The first control mode and the second control mode of the present invention do not interfere with each other. The first control mode and the second control mode can be selected at the same time to adjust the batteries in the fuel cell stack to ensure that the batteries can work normally and extend the battery life.

[0026] Further explanation, the first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency; the first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency includes the following steps: Obtain the open-loop exhaust frequency based on the current stack current; The open-loop exhaust frequency is the exhaust frequency of the fuel cell system during open-loop control. The open-loop exhaust frequency corresponding to the current current can be determined by looking up the table. Specifically, the open-loop exhaust frequency is also the minimum exhaust frequency of the fuel cell system. Setting a first pressure difference threshold; The average voltage values ​​ΔU1 and ΔU2 of the stack before and after the first exhaust of the exhaust valve are obtained respectively, and the absolute difference between ΔU1 and ΔU2 is calculated and recorded as variable ΔU3; If the variable ΔU3 is greater than the first pressure difference threshold, the variable of the open-loop exhaust frequency is increased based on the nitrogen concentration, thereby reducing the nitrogen concentration in the fuel cell stack.

[0027] To further illustrate, the variable of increasing the open-loop exhaust frequency based on nitrogen concentration includes the following control steps: Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals (such as Figure 2 is divided into k intervals as shown); Each interval corresponds to a different exhaust frequency, and the absolute increments of the exhaust frequencies corresponding to adjacent intervals are consistent, all Δf; The nitrogen concentration is directly proportional to the exhaust frequency. The higher the nitrogen concentration, the greater the variable of increasing the open-loop exhaust frequency based on the nitrogen concentration.

[0028] Further explanation: in the first control mode, the nitrogen concentration range is 0%-50%. When the nitrogen concentration in the anode of the fuel cell stack exceeds 50%, the exhaust valve will be opened intermittently according to the nitrogen concentration value until the nitrogen concentration in the anode of the fuel cell stack drops to 0%. The exhaust valve will then be opened according to the open-loop exhaust frequency under the current current.

[0029] The number of intervals divided in the first control mode is not less than 2, and the absolute increment Δf of the exhaust frequency corresponding to adjacent intervals is generally 10%-15% of the open-loop exhaust frequency.

[0030] Further explanation, the second control mode adjusts the wetting uniformity of the battery in the battery stack based on the operating parameters, and the wetting uniformity of the battery in the battery stack includes the following judgment steps: Setting a second pressure difference threshold and a third pressure difference threshold; Obtain the highest voltage and the lowest voltage of all batteries in the battery stack, and calculate the absolute difference between the highest voltage and the lowest voltage, which is recorded as U4; Calculate the absolute differences between the highest voltage and the lowest voltage and the average voltage, respectively, and record them as ΔU5 and ΔU6; When and only when U4 is greater than the second pressure difference threshold, and U5 and ΔU6 are both greater than the third pressure difference threshold, it is determined that the wetting uniformity of the batteries in the battery stack is poor.

[0031] Further explanation, the second control mode adjusts the wetting uniformity of the battery in the battery stack based on the operating parameters, including the following steps: Obtain the current battery stack current and determine the vehicle's operating status based on the current obtained; Determine the wetting status of the battery in the battery stack according to the operating status of the vehicle; The wet state of the battery includes a flooded state and a dry state.

[0032] Specifically, the operating state of the vehicle includes a high-power operating state and a low-power operating state. When the vehicle current is less than a preset current, the vehicle is in a low-power operating state, otherwise it is in a high-power operating state.

[0033] To further explain, if the vehicle has a low battery condition (nitrogen concentration is not high) when operating at high power, it means that the overall wetting degree of the proton exchange membrane in the battery is relatively high (a large amount of liquid water is generated in the battery stack under high power, and the liquid water cannot be discharged from the battery stack in time, causing the liquid water to accumulate on the proton exchange membrane, blocking the holes in the proton exchange membrane). At this time, the wetting state of the battery is a flooded state.

[0034] If the vehicle has a low battery condition (nitrogen concentration is not high) when operating at low power, it means that the overall wetting degree of the proton exchange membrane in the battery is low (under low power, the hydrogen and air intake in the battery stack are very low, resulting in a sudden decrease in liquid water produced in the battery stack, and the proton exchange membrane cannot be well wetted. Therefore, protons cannot be well transferred on the proton exchange membrane, affecting the battery's power generation state). At this time, the battery's wetting state is dry.

[0035] Further explanation, such as Figure 3 As shown, if the battery is in a flooded state, the control steps include the following: Increase the speed of the hydrogen circulation pump to increase the hydrogen flow at the cathode inlet of the fuel cell stack; The increase in hydrogen flow can better purge the anode of the battery stack, thereby taking away more water and alleviating the flooding condition; Increase the opening of the proportional valve to increase the hydrogen pressure at the cathode inlet of the fuel cell stack; The increase in hydrogen pressure can increase the pressure difference between hydrogen and air, thereby inhibiting the diffusion of cathode liquid water to the anode and reducing the wetting degree of the stack anode; Increase the speed of the air compressor to increase the air flow at the anode inlet of the stack; The increase in air flow can increase the purge gas flow of the cathode of the battery stack, so that more water is blown out, thereby alleviating the flooding state; in order to further increase the efficiency of air purge, the present embodiment also includes the following air flow control steps: The air flow rate at the anode inlet of the fuel cell stack was increased to 1.3 times and 1.1 times of the original air flow rate respectively, and the cathode of the fuel cell stack was purged by alternating 1.3 times the original air flow rate and 1.1 times the original air flow rate with equal duration.

[0036] The changing airflow can better remove the moisture at the cathode of the battery stack, allowing the battery to quickly get rid of the flooded state.

[0037] Increase the temperature of the cooling circulating fluid, reduce the temperature difference between the cooling circulating fluid and the fuel cell stack, and increase the evaporation rate of water on the proton exchange membrane.

[0038] The reduction of the temperature difference between the cooling circulating fluid and the fuel cell stack (controlled at 3°C-5°C) will increase the temperature of the fuel cell stack, thereby increasing the evaporation rate of water in the fuel cell stack and reducing the water content in the fuel cell stack.

[0039] Further explanation, such as Figure 4 As shown, if the battery is in a dry state, the control steps include the following: Reduce drainage frequency and increase the humidity of circulating hydrogen; Increase the residence time of the air in the humidifier to increase the humidity of the air entering the cathode of the fuel cell stack; Lower the temperature of the cooling circulating fluid, increase the temperature difference between the cooling circulating fluid and the fuel cell stack, and slow down the evaporation rate of water on the proton exchange membrane.

[0040] To further explain, if the battery is in a dry state, at this time, since the vehicle is in a low-power operation state, the intake of hydrogen and air are both at a low level. In this embodiment, the drainage frequency is reduced to increase the humidity of the circulating hydrogen, thereby moistening the proton exchange membrane on the anode side of the battery stack. Furthermore, by increasing the residence time of the air at the anode of the battery stack entering the humidifier, the air carries more water, thereby moistening the proton exchange membrane on the cathode side of the battery stack. On the other hand, the temperature difference between the cooling circulating fluid and the battery stack can also be increased (controlled at 5°C-8°C) to reduce the temperature in the battery stack, thereby reducing the evaporation rate of water in the battery stack and delaying the drying rate of the proton exchange membrane in the battery.

[0041] In another embodiment of the present invention, taking into account the aging degree of the exhaust valve (wear of the sealing surface will cause the leakage rate to change, and the control accuracy of the exhaust valve will be affected), a third control mode is also set. The third control mode changes the number of interval divisions of the nitrogen concentration according to the aging degree of the exhaust valve, and prolongs the service life of the exhaust valve by changing the opening frequency of the exhaust valve.

[0042] Specifically, Figure 5 As shown, based on the aging degree of the exhaust valve, a third control mode is also included, and the third control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust time; The third control mode comprises the following steps: Obtain the open-loop exhaust duration based on the current stack current; Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals (such as Figure 5 As shown, it is divided into p intervals); Each interval corresponds to a different exhaust time, and the absolute increments of the exhaust time corresponding to adjacent intervals are consistent, both ΔT; The nitrogen concentration is directly proportional to the exhaust time. The higher the nitrogen concentration, the greater the variable of the open-loop exhaust time based on the nitrogen concentration.

[0043] Further explanation, the number of intervals divided in the third control mode is less than the number of intervals divided in the first control mode (i.e., p < k), thereby reducing the number of times the exhaust valve is opened and delaying the aging time of the exhaust valve. On the other hand, since the number of times the exhaust valve is opened is reduced, the opening time of the exhaust valve each time is increased. Specifically, the absolute increment ΔT of the exhaust time corresponding to adjacent intervals is 20%-30% of the open-loop exhaust time.

[0044] Select the appropriate control mode by judging the aging degree of the exhaust valve (judged by the leakage rate): If the exhaust valve is not aged very much, the first control mode is selected to control the exhaust of the exhaust valve. In the first control mode, the nitrogen concentration interval is divided more finely. Relatively speaking, the higher the control accuracy, the smaller the effect of the change of nitrogen concentration in the stack anode on the anode voltage (the anode voltage increases smoothly without sudden changes, ensuring the stability of the working environment of the stack anode).

[0045] If the degree of aging of the exhaust valve is high, the third control mode is selected to perform exhaust control on the exhaust valve. The number of nitrogen concentration intervals in the third control mode is smaller than that in the first control mode. Relatively speaking, the exhaust valve needs to be opened less times, and the frequency of exhaust valve wear is reduced, thereby increasing the service life of the exhaust valve. However, compared with the first control mode, the third control mode is not as accurate in controlling voltage changes as the first control mode, and is suitable for use when the exhaust valve is highly aged.

[0046] This embodiment also provides a fuel cell single low control system, such as Figure 6 As shown, the fuel cell single low control system is used to implement the above control method, including: The parameter module is used to obtain various operating parameters in the battery stack and calculate the judgment data through the obtained parameters; specifically, the parameter module needs to obtain the parameters in the battery stack including the voltage of all batteries, the nitrogen concentration in the battery stack, the open-loop exhaust frequency, the open-loop exhaust duration, the hydrogen flow rate, the air flow rate, the hydrogen pressure, the air pressure, the battery stack current, the battery stack temperature, the coolant temperature and other data; the judgment data includes the average voltage value, the average voltage value of the battery stack before and after the exhaust valve is exhausted for the first time, and other calculation data used to identify the battery status; A judgment module, used to receive various judgment data from the parameter module, and identify the state of the battery in the fuel cell (including wet state, dry state, low power operation state, high power operation state, etc.) through the received various judgment data; A selection module, used for selecting an adaptive control mode for a fuel cell in an abnormal state; The regulating module is used to receive the signal from the selecting module and adjust various operating parameters in the fuel cell stack so that the fuel cell stack returns to normal working state.

[0047] Each module in the above control system (parameter module, judgment module, selection module and adjustment module) can be embedded in or independent of the processor of the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0048] This embodiment also provides a computer device, such as Figure 7As shown, it includes: a memory and a processor; the memory is used to store at least one program; when the program is executed by the processor, the processor implements the control method in the above embodiment. Specifically, the computer device includes a bus and a processor, a memory and a network interface connected to the bus respectively. Among them, the processor is used to provide computing and control capabilities; the memory includes a storage medium (storing an operating system, a computer program and a database) and an internal memory (providing an environment for the operation of the operating system and the computer program); the network interface is used to connect and communicate with an external terminal.

[0049] This embodiment further provides a storage medium, including a computer program, and when the computer program is executed by a processor, the control method in the above embodiment is implemented.

[0050] The present invention can effectively identify the cause of single low battery, and select appropriate control modes (first control mode, second control mode and third control mode) according to different single low battery causes to accurately regulate the battery, so that the battery can be out of the single low state while maintaining a stable internal environment, and the control method of the present invention can be applicable to complex and changeable environments.

[0051] Although the present invention is disclosed through the above embodiments, the protection scope of the present invention is not limited thereto. Without departing from the concept of the present invention, any deformation, replacement, etc. made to the above components shall fall within the scope of the claims of the present invention.

Claims

1. A fuel cell single low control method, characterized in that: The steps include: Obtain the voltage of all batteries in the battery stack, and determine whether the battery in the battery stack is in a single low state based on the average voltage of all batteries; If the battery is in a single low state, the nitrogen concentration in the battery stack and the wetting uniformity of all batteries are obtained respectively, and the first control mode and / or the second control mode are selected to adjust the batteries in the battery stack; Among them, the first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency; The second control mode adjusts the wetting uniformity of the cells in the stack based on the operating parameters.

2. The fuel cell single low control method according to claim 1, characterized in that: The first control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust frequency and includes the following steps: Setting a first pressure difference threshold; Obtain the open-loop exhaust frequency based on the current stack current; The average voltage values ​​ΔU1 and ΔU2 of the stack before and after the first exhaust of the exhaust valve are obtained respectively, and the absolute difference between ΔU1 and ΔU2 is calculated and recorded as variable ΔU3; If the variable ΔU3 is greater than the first pressure difference threshold, the variable of the open-loop exhaust frequency is increased based on the nitrogen concentration to reduce the nitrogen concentration in the fuel cell stack.

3. The fuel cell single low control method according to claim 2, characterized in that: The variable of increasing the open loop exhaust frequency based on nitrogen concentration includes the following control steps: Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals; Each interval corresponds to a different exhaust frequency, and the absolute increments of the exhaust frequencies corresponding to adjacent intervals are consistent, all Δf; The nitrogen concentration is directly proportional to the exhaust frequency. The higher the nitrogen concentration, the greater the variable of increasing the open-loop exhaust frequency based on the nitrogen concentration.

4. The fuel cell single low control method according to claim 1, characterized in that: The wetting uniformity of the battery in the battery stack includes the following judgment steps: Setting a second pressure difference threshold and a third pressure difference threshold; Obtain the highest voltage and the lowest voltage of all batteries in the battery stack, and calculate the absolute difference between the highest voltage and the lowest voltage, which is recorded as U4; Calculate the absolute differences between the highest voltage and the lowest voltage and the average voltage, respectively, and record them as ΔU5 and ΔU6; When and only when U4 is greater than the second pressure difference threshold, and U5 and ΔU6 are both greater than the third pressure difference threshold, it is determined that the wetting uniformity of the batteries in the battery stack is poor.

5. The fuel cell single low control method according to claim 4, characterized in that: The second control mode adjusts the wetting uniformity of the battery in the battery stack based on the operating parameters and includes the following steps: Obtain the current battery stack current and determine the vehicle's operating status based on the current obtained; Determine the wetting status of the battery in the battery stack according to the operating status of the vehicle; The wet state of the battery includes a flooded state and a dry state.

6. The fuel cell single low control method according to claim 5, characterized in that: If the battery is flooded, the following control steps are included: Increase the speed of the hydrogen circulation pump to increase the hydrogen flow at the cathode inlet of the fuel cell stack; Increase the opening of the proportional valve to increase the hydrogen pressure at the cathode inlet of the fuel cell stack; Increase the speed of the air compressor to increase the air flow at the anode inlet of the stack; Increase the temperature of the cooling circulating fluid, reduce the temperature difference between the cooling circulating fluid and the fuel cell stack, and increase the evaporation rate of water on the proton exchange membrane.

7. The fuel cell single low control method according to claim 6, characterized in that: If the battery is in a dry state, the control steps include the following: Reduce drainage frequency and increase the humidity of circulating hydrogen; Increase the residence time of the air in the humidifier to increase the humidity of the air entering the cathode of the fuel cell stack; Lower the temperature of the cooling circulating fluid, increase the temperature difference between the cooling circulating fluid and the fuel cell stack, and slow down the evaporation rate of water on the proton exchange membrane.

8. The fuel cell single low control method according to claim 1, characterized in that: Based on the aging degree of the exhaust valve, a third control mode is also included, wherein the third control mode adjusts the nitrogen concentration in the fuel cell stack based on the exhaust time; The third control mode comprises the following steps: Obtain the open-loop exhaust duration based on the current stack current; Divide the nitrogen concentration in the fuel cell stack into equally spaced intervals; Each interval corresponds to a different exhaust time, and the absolute increments of the exhaust time corresponding to adjacent intervals are consistent, both ΔT; The nitrogen concentration is directly proportional to the exhaust time. The higher the nitrogen concentration, the greater the variable of the open-loop exhaust time based on the nitrogen concentration.

9. A fuel cell single low control system, the fuel cell single low control system is used to implement the control method according to any one of claims 1 to 8, characterized in that: include: The parameter module is used to obtain various operating parameters in the battery stack and calculate the judgment data through the obtained parameters; A judgment module, used to receive various judgment data from the parameter module, and identify the state of the battery in the fuel cell through the received various judgment data; A selection module, used for selecting an adaptive control mode for a fuel cell in an abnormal state; The regulating module is used to receive the signal from the selecting module and adjust various operating parameters in the fuel cell stack so that the fuel cell stack returns to normal working state.

10. A computer device, characterized in that: include: Memory and processor; The memory is used to store at least one program; When the program is executed by a processor, the processor implements the control method as described in any one of claims 1-8.

11. A storage medium comprising a computer program, characterized in that: When the computer program is executed by a processor, the control method according to any one of claims 1 to 8 is implemented.

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