Hydrogen fuel cell system and safety protection control method thereof

Abstract

The application provides a hydrogen fuel cell system and a safety protection control method thereof, and belongs to the technical field of hydrogen fuel cells. The method comprises the following steps: obtaining the insulation resistance of a packaging box with an internal stack and the hydrogen concentration value inside the packaging box; determining whether the hydrogen concentration value is less than or equal to a preset upper limit value of the hydrogen concentration and whether the insulation resistance is greater than or equal to a preset lower limit value of the insulation resistance; if yes, controlling the hydrogen fuel cell system to normally operate, obtaining the humidity value inside the packaging box to adaptively adjust the opening degree of a proportional valve arranged inside the hydrogen fuel cell system and the operating state of an air compressor; and if no, controlling the hydrogen fuel cell system to stop operating, adjusting the opening degree of the proportional valve according to the hydrogen concentration value and the insulation resistance, and controlling the air compressor to rotate. The application can ensure the safe operation of the hydrogen fuel cell system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen fuel cell, in particular to a hydrogen fuel cell system and a safety protection control method thereof. BACKGROUND

[0002] In view of the problems of poor pressing precision of the stack, aging of the sealing ring of the stack or long-time non-operation of the hydrogen fuel cell system, the hydrogen fuel cell is prone to hydrogen leakage, and the leaked hydrogen will first gather in the small space of the packaging box body, and if the gathered hydrogen is not diluted and purged to the atmospheric environment in time, a certain safety hazard will be caused; in addition, the insulation performance and internal environment humidity level of the hydrogen fuel cell are also important indicators affecting the safety performance of the system. SUMMARY

[0003] The main purpose of the present application is to provide a hydrogen fuel cell system and a safety protection control method thereof, by combining the insulation resistance value, the internal hydrogen concentration value and the internal humidity value of the packaging box body, specific control is performed on the adjustable proportional valve and the air compressor provided in the air supply subsystem, so as to ensure the safe operation of the hydrogen fuel cell system.

[0004] To achieve the above-mentioned purpose, one aspect of the present application provides a hydrogen fuel cell system, which comprises a stack subsystem and an air supply subsystem;

[0005] The stack subsystem comprises a stack, a packaging box body and a purge pipe, the stack is arranged in the interior of the packaging box body, and the outlet of the packaging box body is connected to the atmospheric environment through the purge pipe;

[0006] The air supply subsystem comprises a first filter, an air compressor, a intercooler and an adjustable proportional valve, the inlet of the first filter is connected to the atmospheric environment, the outlet of the first filter is connected to the inlet of the air compressor, the first outlet of the air compressor is connected to the inlet of the intercooler, and the outlet of the intercooler is connected to the inlet of the packaging box body through the adjustable proportional valve.

[0007] Further, the air supply subsystem further comprises a humidifier, an expander, an inlet stack stop valve and an outlet stack stop valve;

[0008] The outlet of the intercooler is connected to the first inlet of the humidifier, the first outlet of the humidifier is connected to the first inlet of the stack through the inlet stack stop valve, the first outlet of the stack is connected to the second inlet of the humidifier through the outlet stack stop valve, the second outlet of the humidifier is connected to the first inlet of the expander, the second outlet of the air compressor is connected to the second inlet of the expander, and the outlet of the expander is connected to the atmospheric environment.

[0009] Furthermore, the hydrogen fuel cell system also includes a hydrogen supply subsystem, which includes a hydrogen storage tank, a hydrogen pressure regulating chamber, an ejector, a gas-liquid separator, a pressure reducing valve, a hydrogen proportional valve, a hydrogen discharge valve, and a drain valve.

[0010] The outlet of the hydrogen storage cylinder is connected to the inlet of the hydrogen pressure stabilizing chamber through the pressure reducing valve. The outlet of the hydrogen pressure stabilizing chamber is connected to the first inlet of the ejector through the hydrogen proportional valve. The outlet of the ejector is connected to the second inlet of the fuel cell stack. The second outlet of the fuel cell stack is connected to the inlet of the gas-liquid separator. The first outlet of the gas-liquid separator is connected to the second inlet of the ejector. The second outlet of the gas-liquid separator is connected to the atmospheric environment through the hydrogen discharge valve and the drain valve, respectively.

[0011] Furthermore, the hydrogen fuel cell system also includes a thermal management subsystem, which includes a radiator, a PTC heater, an expansion tank, a deionizer, a water pump, a second filter, and a three-way valve.

[0012] The third outlet of the fuel cell stack is connected to the inlet of the radiator, the inlet of the PTC heater, and the first inlet of the expansion tank. The outlets of the radiator and the PTC heater are connected to the inlet of the water pump via the three-way valve. The outlet of the radiator is connected to the second inlet of the expansion tank. The outlet of the expansion tank is connected to the inlet of the deionizer and the inlet of the water pump. The outlet of the deionizer is connected to the inlet of the water pump. The outlet of the water pump is connected to the inlet of the second filter. The outlet of the second filter is connected to the third inlet of the fuel cell stack.

[0013] To achieve the above objectives, another aspect of this application proposes a safety protection and control method applied to the aforementioned hydrogen fuel cell system, the method comprising:

[0014] Obtain the hydrogen concentration value inside the encapsulation box and the insulation resistance value of the encapsulation box;

[0015] Determine whether the hydrogen concentration value is less than or equal to a preset upper limit value for hydrogen concentration, and whether the insulation resistance value is greater than or equal to a preset lower limit value for insulation resistance.

[0016] If so, the hydrogen fuel cell system is controlled to operate normally, the humidity value inside the encapsulation box is obtained, and the opening degree of the adjustable proportional valve and the operating status of the air compressor are adaptively adjusted according to the humidity value.

[0017] If not, the hydrogen fuel cell system is stopped, and the opening of the adjustable proportional valve is adjusted according to the hydrogen concentration value and the insulation resistance value, and the air compressor is controlled to rotate.

[0018] Furthermore, the adaptive adjustment of the opening degree of the adjustable proportional valve and the operating status of the air compressor based on the humidity value includes:

[0019] Determine whether the humidity value is less than or equal to a preset upper limit humidity value;

[0020] If so, the opening of the adjustable proportional valve is adjusted to the preset first opening to keep the air compressor's operating state unchanged;

[0021] If not, the opening of the adjustable proportional valve is adjusted to a preset second opening, which is greater than the first opening, and the air compressor is controlled to rotate.

[0022] Further, adjusting the opening degree of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes:

[0023] When the hydrogen concentration value is detected to be greater than the upper limit of the hydrogen concentration and the insulation resistance value is greater than or equal to the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset third opening degree, which is greater than the second opening degree.

[0024] Further, adjusting the opening degree of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes:

[0025] When the hydrogen concentration value is detected to be less than or equal to the upper limit of the hydrogen concentration and the insulation resistance value is less than the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset fourth opening degree, which is greater than the third opening degree.

[0026] Further, adjusting the opening degree of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes:

[0027] When the hydrogen concentration value is detected to be greater than the upper limit of the hydrogen concentration and the insulation resistance value is less than the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset fifth opening degree, which is greater than the fourth opening degree and less than 100%.

[0028] Furthermore, the method also includes: when the hydrogen fuel cell system is in the start-up phase, adjusting the opening of the adjustable proportional valve to 100%.

[0029] This application includes at least the following beneficial effects: By replacing the original bypass valve with an adjustable proportional valve in the air supply subsystem, the surge problem caused by the air compressor in the air supply subsystem can be eliminated during the start-up phase of the hydrogen fuel cell system, thus optimizing the structural design. By monitoring the insulation resistance, internal hydrogen concentration, and internal humidity of the encapsulation box of the built-in fuel cell stack, the opening degree of the adjustable proportional valve and the operating status of the air compressor in the hydrogen fuel cell system and its air supply subsystem can be effectively adjusted. This allows for the dilution and purging of hydrogen accumulated inside the encapsulation box into the atmosphere when hydrogen leakage occurs. It also allows for the purging of a large amount of humid ambient air inside the encapsulation box into the atmosphere, ensuring that the hydrogen concentration and ambient humidity inside the encapsulation box remain within a safe range. This improves the insulation performance of the hydrogen fuel cell, ensures the safe operation of the hydrogen fuel cell system, and guarantees personnel safety. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a hydrogen fuel cell system provided in an embodiment of this application;

[0031] Figure 2 This is a flowchart illustrating a security protection and control method provided in an embodiment of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of systems and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0033] It is understood that the terms "first," "second," etc., used in this application may be used to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0035] Hydrogen, as a clean, zero-carbon secondary energy source, can be used as fuel in hydrogen fuel cell vehicles. It works by converting chemical energy into electrical energy through an electrochemical reaction between hydrogen and oxygen in the air, thus powering the vehicle. However, hydrogen has a wide combustion range (4.1%-74.1% by volume), a low ignition energy, and readily forms flammable mixtures in air. Once it encounters an ignition source, it is prone to combustion or explosion. Furthermore, hydrogen molecules are small, making them highly susceptible to permeation and leakage from materials.

[0036] In hydrogen fuel cells, the stack is typically sealed using built-in sealing rings. However, considering issues such as poor stack pressing accuracy, aging of the stack sealing rings, or prolonged periods of inactivity of the hydrogen fuel cell system, hydrogen fuel cells are prone to hydrogen leakage. The leaked hydrogen will first accumulate in large quantities inside the confined enclosure. If measures are not taken in time to dilute the accumulated hydrogen and purge it into the atmosphere, it will pose certain safety hazards.

[0037] Furthermore, the insulation performance and internal humidity level of a hydrogen fuel cell are also important indicators affecting the system's safety performance. When a hydrogen fuel cell is operating, its internal environment needs to be kept relatively dry. This may be related to factors such as thin insulation plates and short creepage distances. When the ambient humidity is high, water vapor condenses into water droplets that adhere to the cooler bipolar plates. At this time, electrons can travel from the current collector across the insulation plate to the end plate, causing conductivity between the bipolar plates and the end plate. Therefore, the insulation resistance decreases, potentially endangering personal safety. Thus, certain measures are needed to ensure that the internal humidity of the hydrogen fuel cell is safely controllable.

[0038] In view of this, this application provides a hydrogen fuel cell system and its safety protection and control method. This solution replaces the original bypass valve with an adjustable proportional valve in the air supply subsystem, eliminating surge problems caused by the air compressor in the air supply subsystem during the start-up phase of the hydrogen fuel cell system, thus optimizing the structural design. By monitoring the insulation resistance, internal hydrogen concentration, and internal humidity of the encapsulation box of the built-in fuel cell stack, the opening degree of the adjustable proportional valve and the operating status of the air compressor in the hydrogen fuel cell system and its air supply subsystem can be effectively adjusted. This allows for the dilution and purging of accumulated hydrogen inside the encapsulation box into the atmosphere when hydrogen leakage occurs. It also allows for the purging of a large amount of humid ambient air inside the encapsulation box into the atmosphere, ensuring that the hydrogen concentration and ambient humidity inside the encapsulation box remain within a safe range. This improves the insulation performance of the hydrogen fuel cell, ensures the safe operation of the hydrogen fuel cell system, and guarantees personnel safety.

[0039] Figure 1This is a schematic diagram of a hydrogen fuel cell system provided in an embodiment of this application. The hydrogen fuel cell system includes a stack subsystem, an air supply subsystem, a hydrogen supply subsystem, and a thermal management subsystem.

[0040] Specifically, the fuel cell stack subsystem includes a fuel cell stack 101, an enclosure 102, and a purge pipe 103. The fuel cell stack 101 is disposed inside the enclosure 102. The outlet of the enclosure 102 is connected to the atmospheric environment through the purge pipe 103. A hydrogen sensor 104 and a humidity sensor 105 are disposed inside the enclosure 102. An insulation detector 106 is disposed on the outer surface of the enclosure 102. The hydrogen sensor 104 is used to detect the hydrogen concentration inside the enclosure 102, the humidity sensor 105 is used to detect the humidity inside the enclosure 102, and the insulation detector 106 is used to detect the insulation resistance of the enclosure 102 online. When a hydrogen leak occurs in the hydrogen fuel cell, a large amount of hydrogen accumulated inside the encapsulation box 102 is discharged into the atmosphere through the purge pipe 103; and when the ambient humidity inside the encapsulation box 102 exceeds the safe range, the humid air inside the encapsulation box 102 is also discharged into the atmosphere through the purge pipe 103.

[0041] Specifically, the air supply subsystem is mainly used to provide an appropriate amount of air for the electrochemical reaction of the fuel cell stack 101. It includes a first filter 201, an air compressor 202, an intercooler 203, a humidifier 204, an expander 205, an adjustable proportional valve 206, an infeed shut-off valve 207, and an outfeed shut-off valve 208. The first filter 201 is preferably a particulate filter to filter impurities in the air.

[0042] The inlet of the first filter 201 is connected to the atmospheric environment, and the outlet of the first filter 201 is connected to the inlet of the air compressor 202. The first outlet of the air compressor 202 is connected to the inlet of the intercooler 203, and the outlet of the intercooler 203 is connected to the inlet of the encapsulation housing 102 through the adjustable proportional valve 206. By adjusting the opening of the adjustable proportional valve 206 and the operating state of the air compressor 202, the amount of air entering the encapsulation housing 102 can be increased to a certain extent, thereby improving the efficiency of hydrogen and / or ambient humid air inside the encapsulation housing 102 being discharged to the atmospheric environment.

[0043] The outlet of the intercooler 203 is connected to the first inlet of the humidifier 204. The first outlet of the humidifier 204 is connected to the first inlet of the fuel cell stack 101 via the inlet shut-off valve 207. This forms a first pipeline between the first outlet of the humidifier 204 and the first inlet of the fuel cell stack 101. This first pipeline passes through the enclosure 102, and the inlet shut-off valve 207 is installed on this first pipeline. This first pipeline is used to supply high-quality air to the fuel cell stack 101. The first outlet of the fuel cell stack 101 is connected to the second inlet of the humidifier 204 via the outlet shut-off valve 208. This forms a second pipeline between the first outlet of the fuel cell stack 101 and the second inlet of the humidifier 204. A pipeline runs through the enclosure 102, and a stack-out stop valve 208 is installed on the second pipeline. The second pipeline is used to transport excess air discharged from the fuel cell stack 101 to the humidifier 204, so that the humidifier 204 can mix and exchange the moisture in the excess air discharged from the fuel cell stack 101 with the moisture in the air transported by the intercooler 203. The second outlet of the humidifier 204 is connected to the first inlet of the expander 205, and the second outlet of the air compressor 202 is connected to the second inlet of the expander 205. The outlet of the expander 205 is connected to the atmospheric environment, so that the expander 205 can recover energy from the gas discharged from the air compressor 202 and the humidifier 204, thereby increasing system efficiency.

[0044] Specifically, the hydrogen supply subsystem is mainly used to provide an appropriate amount of hydrogen for the electrochemical reaction of the fuel cell stack 101. It includes a hydrogen storage cylinder 301, a hydrogen pressure stabilizing chamber 302, an ejector 303, a gas-liquid separator 304, a pressure reducing valve 305, a hydrogen proportional valve 306, a hydrogen discharge valve 307, and a drain valve 308.

[0045] The outlet of the hydrogen storage cylinder 301 is connected to the inlet of the hydrogen pressure regulating chamber 302 via the pressure reducing valve 305. The outlet of the hydrogen pressure regulating chamber 302 is connected to the first inlet of the ejector 303 via the hydrogen proportioning valve 306. The outlet of the ejector 303 is connected to the second inlet of the fuel cell stack 101, forming a third pipeline between the first inlet of the ejector 303 and the second inlet of the fuel cell stack 101. This third pipeline passes through the encapsulation housing 102 and is used to supply high-quality hydrogen to the fuel cell stack 101. The second outlet of the fuel cell stack 101 is connected to the inlet of the gas-liquid separator 304, meaning that the gas-liquid separator 304 separates from the gas-liquid separator at the second outlet of the fuel cell stack 101. A fourth pipeline is formed between the inlets of the separator 304 and the encapsulation housing 102. This fourth pipeline is used to transport excess hydrogen discharged from the fuel cell stack 101 to the gas-liquid separator 304, so that the gas-liquid separator 304 can separate the hydrogen discharged from the fuel cell stack 101 into liquid water and gas, and then transport the separated hydrogen back to the fuel cell stack 101 for recycling. The first outlet of the gas-liquid separator 304 is connected to the second inlet of the ejector 303. The second outlet of the gas-liquid separator 304 is connected to the atmospheric environment through the hydrogen discharge valve 307 and the drain valve 308.

[0046] Specifically, the thermal management subsystem is used to control the operating temperature environment of the fuel cell stack 101. It includes a radiator 401, a PTC (Positive Temperature Coefficient) heater 402, an expansion tank 403, a deionizer 404, a water pump 405, a second filter 406, and a three-way valve 407. The heat dissipation efficiency can be improved by installing a fan on the radiator 401. The second filter 406 is preferably a particulate filter to filter impurities in the flowing coolant.

[0047] The third outlet of the fuel cell stack 101 is connected to the inlet of the radiator 401, the third outlet of the fuel cell stack 101 is connected to the inlet of the PTC heater 402, the third outlet of the fuel cell stack 101 is connected to the first inlet of the expansion tank 403, the outlet of the radiator 401 is connected to the inlet of the water pump 405 through the three-way valve 407, the outlet of the PTC heater 402 is connected to the inlet of the water pump 405 through the three-way valve 407, the outlet of the radiator 401 is connected to the second inlet of the expansion tank 403, the outlet of the expansion tank 403 is connected to the inlet of the deionizer 404, the outlet of the expansion tank 403 is connected to the inlet of the water pump 405, the outlet of the deionizer 404 is connected to the inlet of the water pump 405, the outlet of the water pump 405 is connected to the inlet of the second filter 406, and the outlet of the second filter 406 is connected to the third inlet of the fuel cell stack 101.

[0048] The hydrogen fuel cell system proposed in this application eliminates the surge problem caused by the air compressor in the air supply subsystem when the hydrogen fuel cell system is in the start-up phase by replacing the original bypass valve with an adjustable proportional valve in the air supply subsystem, thus optimizing the structural design.

[0049] Figure 2 This is a schematic flowchart of an optional safety protection and control method provided in an embodiment of this application, mainly applied to the aforementioned hydrogen fuel cell system. Figure 2 The method may include, but is not limited to, steps S501 to S504:

[0050] Step S501: Obtain the hydrogen concentration value inside the encapsulation box and the insulation resistance value of the encapsulation box;

[0051] Step S502: Determine whether the hydrogen concentration value is less than or equal to the preset upper limit of hydrogen concentration and whether the insulation resistance value is greater than or equal to the preset lower limit of insulation resistance. If yes, it means that there is no hydrogen leakage inside the encapsulation box and the overall insulation performance is good. At this time, proceed to step S503. If no, proceed to step S504.

[0052] Step S503: Control the normal operation of the hydrogen fuel cell system, obtain the humidity value inside the encapsulation box, and then make adaptive adjustments to the opening degree of the adjustable proportional valve and the operating status of the air compressor based on the humidity value.

[0053] Step S504: Control the hydrogen fuel cell system to stop operating, then adjust the opening of the adjustable proportional valve according to the hydrogen concentration value and the insulation resistance value, and control the air compressor to rotate.

[0054] Steps S501 to S504, as shown in the embodiments of this application, combine the insulation resistance of the encapsulation box, the internal hydrogen concentration, and the internal humidity to specifically control the adjustable proportional valve and air compressor in the air supply subsystem, thereby ensuring the safe operation of the hydrogen fuel cell system.

[0055] It should be noted that when the hydrogen fuel cell system is in normal operation, steps S501 to S502 can be repeated to perform system safety testing and determination.

[0056] In step S503 of some embodiments, the opening degree of the adjustable proportional valve and the operating state of the air compressor are adaptively adjusted according to the humidity value. Specific implementation methods include the following:

[0057] Determine whether the humidity value is less than or equal to the preset upper limit of humidity;

[0058] If so, it means that the ambient humidity of the fuel cell stack inside the enclosure is low. At this time, adjust the opening of the adjustable proportional valve to the preset first opening, and keep the air compressor running unchanged. Only maintain the small amount of air required for the fuel cell stack to purge during normal operation, so that the hydrogen concentration and ambient humidity inside the enclosure are stable within a safe range.

[0059] If not, it indicates that the ambient humidity of the fuel cell stack is relatively high, which may easily lead to a decrease in the overall insulation performance. In this case, the opening of the adjustable proportional valve is adjusted to the preset second opening, which is greater than the first opening, and the air compressor is controlled to rotate, so that more air enters the encapsulation box to quickly remove the humid gas in the environment, thereby reducing the ambient humidity of the fuel cell stack.

[0060] It should be noted that if the opening of the adjustable proportional valve is adjusted to the second opening and the air compressor is controlled to rotate, this operating state needs to be maintained for a specific period of time so that the humidity inside the enclosure can be restored to a safe range as soon as possible.

[0061] The first opening value ranges from 5% to 10%, the second opening value ranges from 15% to 25%, and the first opening value is preferably set to 8%, and the second opening value is preferably set to 20%.

[0062] It should be noted that the upper limit of hydrogen concentration, the lower limit of insulation resistance, and the upper limit of humidity are all set based on the past practical experience of technical personnel, and this application does not make specific limitations on them.

[0063] In step S504 of some embodiments, the opening degree of the adjustable proportional valve is adjusted according to the hydrogen concentration value and the insulation resistance value. Specific implementations include the following three cases:

[0064] In the first scenario, when the hydrogen concentration value is detected to be greater than the upper limit of the hydrogen concentration value and the insulation resistance value is greater than or equal to the lower limit of the insulation resistance value, it indicates that there is hydrogen leakage inside the packaging box but the overall insulation performance is good. At this time, the opening of the adjustable proportional valve is adjusted to the preset third opening degree, which is greater than the second opening degree. The rotation of the air compressor is used to allow more air to enter the packaging box to quickly dilute the leaked hydrogen and discharge it into the atmosphere, thereby reducing the hydrogen concentration inside the packaging box.

[0065] It should be noted that if the opening of the adjustable proportional valve is adjusted to the third opening and the air compressor is controlled to rotate, this operating state needs to be maintained for a specific period of time so that the hydrogen concentration inside the encapsulation box can be restored to within a safe range as soon as possible.

[0066] In the second scenario, when the hydrogen concentration value is less than or equal to the upper limit of the hydrogen concentration value and the insulation resistance value is less than the lower limit of the insulation resistance value, it indicates that there is no hydrogen leakage inside the packaging box, but the overall insulation performance is poor, which may endanger personal safety. In this case, the opening of the adjustable proportional valve is adjusted to the preset fourth opening degree, which is greater than the third opening degree. The rotation of the air compressor is used to allow more air to enter the packaging box to quickly blow out the humid air inside the packaging box, thereby reducing the ambient humidity of the fuel cell stack and improving the overall insulation performance.

[0067] It should be noted that if the opening degree of the adjustable proportional valve is adjusted to the fourth opening degree and the air compressor is controlled to rotate, this operating state needs to be maintained for a specific period of time so that the insulation resistance of the enclosure can be restored to within the safe range as soon as possible.

[0068] In the third scenario, when the hydrogen concentration is detected to be greater than the upper limit and the insulation resistance is less than the lower limit, it indicates that there is hydrogen leakage inside the enclosure and the overall insulation performance is poor, posing a serious safety risk. In this case, the opening of the adjustable proportional valve is adjusted to a preset fifth opening, which is greater than the fourth opening and less than 100%. The rotation of the air compressor allows a large amount of air to enter the enclosure, which not only quickly dilutes the leaked hydrogen and discharges it into the atmosphere to reduce the hydrogen concentration inside the enclosure, but also quickly blows out the humid air inside the enclosure to reduce the humidity of the environment where the fuel cell stack is located.

[0069] It should be noted that if the opening degree of the adjustable proportional valve is adjusted to the fifth opening degree and the air compressor is controlled to rotate, this operating state needs to be maintained for a specific period of time so that the insulation resistance of the enclosure and the internal hydrogen concentration can be restored to within a safe range as soon as possible.

[0070] The value range of the third opening is 55%-65%, the value range of the fourth opening is 75%-85%, and the value range of the fifth opening is 85%-95%. The third opening is preferably set to 60%, the fourth opening is preferably set to 80%, and the fifth opening is preferably set to 90%.

[0071] In some embodiments, the safety protection control method further includes: when the hydrogen fuel cell system is in the start-up phase, adjusting the opening of the adjustable proportional valve to 100%, so that the adjustable proportional valve in the fully open state can replace the bypass valve function, thereby solving the surge problem of the air compressor.

[0072] The safety protection and control method proposed in this application monitors the insulation resistance, internal hydrogen concentration, and internal humidity of the encapsulation box of the built-in fuel cell stack. This allows for effective adjustment of the opening of the adjustable proportional valve and the operating status of the air compressor in the hydrogen fuel cell system and its air supply subsystem. In the event of hydrogen leakage from the fuel cell, the hydrogen accumulated inside the encapsulation box can be diluted and purged into the atmosphere. Furthermore, a large amount of humid air inside the encapsulation box can be purged into the atmosphere, ensuring that the hydrogen concentration and humidity inside the encapsulation box remain within a safe range. This improves the insulation performance of the hydrogen fuel cell, ensures the safe operation of the hydrogen fuel cell system, and guarantees personnel safety.

[0073] Although the description of this application has been quite detailed and particularly focused on several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment. Rather, it should be considered as effectively covering the intended scope of this application by referring to the appended claims and taking into account the prior art, which provides for a broad possible interpretation of these claims. Furthermore, the foregoing description of this application with respect to embodiments foreseeable by the inventors is intended to provide a useful description, and non-substantial modifications to this application that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A safety protection and control method for a hydrogen fuel cell system, characterized in that, The hydrogen fuel cell system includes a stack subsystem and an air supply subsystem. The stack subsystem includes a fuel cell stack, a housing, and a purge pipe. The fuel cell stack is disposed inside the housing, and the outlet of the housing is connected to the atmosphere via the purge pipe. The air supply subsystem includes a first filter, an air compressor, an intercooler, and an adjustable proportional valve. The inlet of the first filter is connected to the atmosphere, the outlet of the first filter is connected to the inlet of the air compressor, the first outlet of the air compressor is connected to the inlet of the intercooler, and the outlet of the intercooler is connected to the inlet of the housing via the adjustable proportional valve. A hydrogen sensor and a humidity sensor are installed inside the housing, and an insulation detector is installed on the outer surface of the housing. The hydrogen sensor detects the hydrogen concentration inside the housing, the humidity sensor detects the humidity inside the housing, and the insulation detector detects the insulation resistance of the housing online. The method includes: Obtain the hydrogen concentration value inside the encapsulation box and the insulation resistance value of the encapsulation box; Determine whether the hydrogen concentration value is less than or equal to a preset upper limit value for hydrogen concentration, and whether the insulation resistance value is greater than or equal to a preset lower limit value for insulation resistance. If so, the hydrogen fuel cell system is controlled to operate normally, the humidity value inside the encapsulation box is obtained, and the opening degree of the adjustable proportional valve and the operating status of the air compressor are adaptively adjusted according to the humidity value. If not, the hydrogen fuel cell system is stopped, and the opening of the adjustable proportional valve is adjusted according to the hydrogen concentration value and the insulation resistance value, and the air compressor is controlled to rotate.

2. The safety protection and control method according to claim 1, characterized in that, The adaptive adjustment of the opening degree of the adjustable proportional valve and the operating status of the air compressor based on the humidity value includes: Determine whether the humidity value is less than or equal to a preset upper limit humidity value; If so, the opening of the adjustable proportional valve is adjusted to the preset first opening to keep the air compressor's operating state unchanged; If not, the opening of the adjustable proportional valve is adjusted to a preset second opening, which is greater than the first opening, and the air compressor is controlled to rotate.

3. The safety protection and control method according to claim 2, characterized in that, The step of adjusting the opening of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes: When the hydrogen concentration value is detected to be greater than the upper limit of the hydrogen concentration and the insulation resistance value is greater than or equal to the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset third opening degree, which is greater than the second opening degree.

4. The safety protection and control method according to claim 3, characterized in that, The step of adjusting the opening of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes: When the hydrogen concentration value is detected to be less than or equal to the upper limit of the hydrogen concentration and the insulation resistance value is less than the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset fourth opening degree, which is greater than the third opening degree.

5. The safety protection and control method according to claim 4, characterized in that, The step of adjusting the opening of the adjustable proportional valve based on the hydrogen concentration value and the insulation resistance value includes: When the hydrogen concentration value is detected to be greater than the upper limit of the hydrogen concentration and the insulation resistance value is less than the lower limit of the insulation resistance value, the opening degree of the adjustable proportional valve is adjusted to a preset fifth opening degree, which is greater than the fourth opening degree and less than 100%.

6. The safety protection and control method according to claim 1, characterized in that, The method further includes: when the hydrogen fuel cell system is in the start-up phase, adjusting the opening of the adjustable proportional valve to 100%.

7. The safety protection and control method according to claim 1, characterized in that, The air supply subsystem also includes a humidifier, an expander, an infeed shut-off valve, and an outfeed shut-off valve; The outlet of the intercooler is connected to the first inlet of the humidifier. The first outlet of the humidifier is connected to the first inlet of the fuel cell stack through the inlet shut-off valve. The first outlet of the fuel cell stack is connected to the second inlet of the humidifier through the outlet shut-off valve. The second outlet of the humidifier is connected to the first inlet of the expander. The second outlet of the air compressor is connected to the second inlet of the expander. The outlet of the expander is connected to the atmospheric environment.

8. The safety protection and control method according to claim 1, characterized in that, The hydrogen fuel cell system also includes a hydrogen supply subsystem, which includes a hydrogen storage tank, a hydrogen pressure regulating chamber, an ejector, a gas-liquid separator, a pressure reducing valve, a hydrogen proportional valve, a hydrogen discharge valve, and a drain valve. The outlet of the hydrogen storage cylinder is connected to the inlet of the hydrogen pressure stabilizing chamber through the pressure reducing valve. The outlet of the hydrogen pressure stabilizing chamber is connected to the first inlet of the ejector through the hydrogen proportional valve. The outlet of the ejector is connected to the second inlet of the fuel cell stack. The second outlet of the fuel cell stack is connected to the inlet of the gas-liquid separator. The first outlet of the gas-liquid separator is connected to the second inlet of the ejector. The second outlet of the gas-liquid separator is connected to the atmospheric environment through the hydrogen discharge valve and the drain valve, respectively.

9. The safety protection and control method according to claim 1, characterized in that, The hydrogen fuel cell system also includes a thermal management subsystem, which includes a radiator, a PTC heater, an expansion tank, a deionizer, a water pump, a second filter, and a three-way valve. The third outlet of the fuel cell stack is connected to the inlet of the radiator, the inlet of the PTC heater, and the first inlet of the expansion tank. The outlets of the radiator and the PTC heater are connected to the inlet of the water pump via the three-way valve. The outlet of the radiator is connected to the second inlet of the expansion tank. The outlet of the expansion tank is connected to the inlet of the deionizer and the inlet of the water pump. The outlet of the deionizer is connected to the inlet of the water pump. The outlet of the water pump is connected to the inlet of the second filter. The outlet of the second filter is connected to the third inlet of the fuel cell stack.

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