An Online Diagnosis Method, Storage Medium and System for a Humidifier of a Fuel Cell System

Abstract

The present invention provides an online diagnosis method, storage medium and system for a humidifier of a fuel cell system. The method includes: maintaining the fuel cell within a preset temperature range and performing the following steps: purging the cathode of the fuel cell until the wet side of the humidifier is in a pressure holding state and the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) at this time; respectively obtaining the wet side pressure and wet side temperature of the humidifier before and after the interval time when the dry side of the humidifier is connected to the atmospheric environment; obtaining the gas leakage rate of the humidifier according to the ideal gas law; when the gas leakage rate is greater than a preset failure value, perform the steps of: determining that the humidifier fails and giving a prompt. The beneficial effect of the present invention is: diagnosing the leakage rate of the humidifier online, and then judging whether the humidifier reaches the end of its life, so as to replace the humidifier in time and improve the life of the fuel cell system.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and particularly to an online diagnosis method, a storage medium, and a system for a humidifier of a fuel cell system. Background Art

[0002] A humidifier is a component used for air humidification in a fuel cell engine. Generally, a membrane humidifier is adopted. That is, air with high humidity enters one side of the humidifier, generally the air at the cathode outlet of the fuel cell, and dry air, that is, the air to enter the fuel cell, enters the other side. Due to the humidity difference between the air on both sides of the humidifier membrane, the moisture in the wet-side air will permeate through the membrane to the dry-side air, so as to achieve the purpose of humidifying the dry-side air entering the fuel cell.

[0003] Over time, micropores or even larger holes will appear in the membrane material of the humidifier. The air with higher pressure on the dry side will leak to the air side with lower pressure on the wet side and then be discharged out of the system. In this way, the amount of air entering the fuel cell will decrease. If it cannot be diagnosed in time, the fuel cell will be in a non-optimal working state for a long time, thus affecting the service life of the fuel cell. Summary of the Invention

[0004] To solve the above problems, the present invention provides an online diagnosis method, a storage medium, and a system for a humidifier of a fuel cell system. Among them, an online diagnosis method for a humidifier of a fuel cell system includes the steps of:

[0005] Maintain the fuel cell within a preset temperature range and perform the following steps:

[0006] Purge the cathode of the fuel cell until the wet side of the humidifier is in a pressure-holding state and the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) at this time;

[0007] Obtain the wet-side pressure and wet-side temperature of the humidifier before and after the time interval when the dry side of the humidifier is connected to the atmospheric environment respectively;

[0008] Obtain the gas leakage rate of the humidifier according to the ideal gas law;

[0009] When the gas leakage rate is greater than a preset failure value, perform the steps of:

[0010] Determine that the humidifier fails and give a prompt.

[0011] Further, the ideal gas law satisfies:

[0012] Q1 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1

[0013] Wherein, Q1 is the gas leakage rate of the humidifier, and the unit is m 3 / s; n is the amount of substance of air, with the unit of mol; R is the molar gas constant, with the unit of J / (mol*K); Tc1 is the wet side temperature of the humidifier before the interval time, with the unit of K; Pm1 is the wet side pressure of the humidifier before the interval time, with the unit of Pa; Tc2 is the wet side temperature of the humidifier after the interval time, with the unit of K; Pm2 is the wet side pressure of the humidifier after the interval time, with the unit of Pa; tm1 is the interval time, with the unit of s.

[0014] Furthermore, the ideal gas law is satisfied as:

[0015] Q2 = n*R[Tc1 / Pm1 - Tc2 / Pm2] / tm1 - Qc

[0016] where, Q2 is the revised value of Q1, with the unit of m 3 / s; Qc is the leakage rate of the pipeline where the wet side of the humidifier is located, with the unit of m 3 / s.

[0017] Further, the cathode purges the fuel cell until the wet side of the humidifier is in a pressure holding state and at this time the wet side pressure of the humidifier is not less than 30 KPa (gauge pressure), which specifically includes the steps of:

[0018] Run the air compressor at a preset speed to purge the fuel cell through the cathode, and adjust the opening of the second valve component so that the wet side pressure of the humidifier is not less than 30 KPa (gauge pressure) and not greater than 150 KPa (gauge pressure);

[0019] Then gradually open the bypass valve, and at the same time gradually close the second valve component and when the second valve component is in the closed state, the wet side pressure of the humidifier is not less than 30 KPa (gauge pressure);

[0020] Then close the air compressor and the first valve component and keep the bypass valve in the open state, the wet side of the humidifier is in a pressure holding state and the wet side pressure is not less than 30 KPa (gauge pressure); where, the air compressor is arranged on the cathode inlet pipeline, the second valve component is arranged on the cathode outlet pipeline and is arranged near the wet side outlet end of the humidifier, the first valve component is arranged on the cathode outlet pipeline and is arranged between the fuel cell and the humidifier; the bypass valve is arranged on the cathode bypass pipeline, and the cathode bypass pipeline is used to connect the cathode inlet pipeline with the atmospheric environment.

[0021] Further, the specific steps for obtaining the wet side pressure and wet side temperature of the humidifier before and after the interval time when the dry side of the humidifier is connected to the atmospheric environment include:

[0022] Obtain the wet side pressure and wet side temperature of the humidifier before and after the interval time respectively.

[0023] Further, the obtaining of the wet side pressure and wet side temperature of the humidifier before and after the time interval when the dry side of the humidifier is connected to the atmospheric environment specifically includes the steps of:

[0024] Obtain the wet side pressure and wet side temperature of the humidifier in a pressure-holding state; synchronously connect the dry side of the humidifier to the atmospheric environment until the time interval, and then obtain the wet side pressure and wet side temperature of the humidifier again.

[0025] Further, the obtaining of the wet side pressure and wet side temperature of the humidifier before and after the time interval when the dry side of the humidifier is connected to the atmospheric environment specifically includes the steps of:

[0026] Connect the dry side of the humidifier to the atmospheric environment; respectively obtain the wet side pressure and wet side temperature of the humidifier before and after the time interval; or,

[0027] Connect the dry side of the humidifier to the atmospheric environment; when the wet side pressure of the humidifier drops to the first target pressure range, obtain the wet side pressure and wet side temperature of the humidifier, and record the acquisition time t1; when the wet side pressure of the humidifier drops to the second target pressure range, obtain the wet side pressure and wet side temperature of the humidifier again, and record the acquisition time t2; wherein, the difference between the acquisition time t2 and the acquisition time t1 is the time interval.

[0028] Further, the method further includes the steps of:

[0029] When the gas leakage rate is not greater than the preset failure value, execute the steps of: determining that the humidifier is effective and giving a prompt; and / or,

[0030] Stop maintaining the fuel cell within a preset temperature range and shut down the accessories of the fuel cell system; and / or,

[0031] Before maintaining the fuel cell within a preset temperature range, the method further includes the steps of: obtaining a shutdown instruction; executing the shutdown purge strategy of the fuel cell.

[0032] The present invention also provides a computer storage medium, which stores multiple instructions, and the instructions are applicable to be loaded and executed by a processor for the online diagnosis method of the humidifier of the fuel cell system.

[0033] The present invention also provides an online diagnosis system for a humidifier of a fuel cell system, including:

[0034] A fuel cell, a cathode inlet pipeline, a cathode outlet pipeline, a cathode bypass pipeline, a humidifier, a thermal management system, and a controller;

[0035] Wherein, the cathode inlet gas pipeline, the dry side of the humidifier, the fuel cell, the wet side of the humidifier, and the cathode outlet gas pipeline are connected in sequence; an air compressor is provided in the cathode inlet gas pipeline; a first valve member is provided between the fuel cell and the wet side of the humidifier; a second valve member is provided in the cathode outlet gas pipeline; the cathode inlet gas pipeline is connected to the atmospheric environment through the cathode bypass pipeline; the thermal management system is used to adjust the temperature of the fuel cell; the controller is configured to execute the online diagnosis method for the humidifier of the fuel cell system described in any one of the above.

[0036] Further, the thermal management system includes: a cooling pump, a radiator, a heater, and a thermostat; wherein,

[0037] One end of the cooling pump is connected to the fuel cell outlet, and the other end is respectively connected to one end of the radiator and one end of the heater. The other end of the heater is connected to one end of the thermostat, and the other end of the radiator is connected to the other end of the thermostat.

[0038] Further, along the gas flow direction, an air filter and an intercooler are sequentially provided in the cathode inlet gas pipeline, and both ends of the air compressor are respectively connected to the air filter and the intercooler.

[0039] The beneficial effects brought by the technical solution provided by the present invention are: without additionally increasing the components of the fuel cell engine, an online diagnosis method for the humidifier of the fuel cell system is provided, which is used to maintain the pressure on the wet side of the humidifier, and according to the rate of pressure reduction, online diagnose the gas leakage rate of the humidifier, and then judge whether the humidifier reaches the end of its life, so as to replace the humidifier in time and improve the life of the fuel cell system. Description of the Drawings

[0040] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0041] Figure 1 is a flowchart of the online diagnosis method for the humidifier of the fuel cell system disclosed in the embodiment of the present invention;

[0042] Figure 2 is a framework diagram of the online diagnosis system for the humidifier of the fuel cell system disclosed in the embodiment of the present invention.

[0043] Wherein: A-1 - fuel cell, A-2 - cathode inlet pipeline, A-3 - thermal management system, A-4 - cathode outlet pipeline, A-5 - cathode bypass pipeline, C-1 - pressure sensor 1, C-2 - air filter, C-3 - flow and temperature integrated sensor, C-4 - air compressor, C-5 - intercooler, C-6 - bypass valve, C-7 - air intake throttle valve, C-8 - pressure sensor 2, C-9 - humidifier, C-10 - temperature and pressure integrated sensor, C-11 - fuel cell outlet throttle valve, C-12 - air back pressure valve, W-1 - fuel cell outlet temperature sensor, W-2 - cooling pump, W-3 - radiator, W-4 - heater, i.e., PTC; W-5 - thermostat, W-6 - fuel cell inlet temperature sensor. Detailed implementation manners

[0044] For a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation manners of the present invention will now be described in detail with reference to the accompanying drawings.

[0045] As Figure 1 shown, the present invention provides an online diagnosis method for a humidifier of a fuel cell system, including the steps of:

[0046] S1, maintaining the fuel cell within a preset temperature range;

[0047] And performing the following steps:

[0048] S2, purging the fuel cell at the cathode until the wet side of the humidifier is in a pressure-holding state and the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) at this time;

[0049] S3, respectively obtaining the wet side pressure and wet side temperature of the humidifier before and after the dry side of the humidifier is connected to the atmospheric environment for an interval time;

[0050] S4, obtaining the gas leakage rate of the humidifier according to the ideal gas law;

[0051] When the gas leakage rate is greater than a preset failure value, perform the steps of:

[0052] S5, determining that the humidifier fails and giving a prompt.

[0053] Further, the ideal gas law is satisfied as:

[0054] Q1 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1

[0055] Wherein, Q1 is the gas leakage rate of the humidifier, with the unit of m 3 / s; n is the amount of substance of air, with the unit of mol; R is the molar gas constant, with the unit of J / (mol*K); Tc1 is the wet-side temperature of the humidifier before the interval time, with the unit of K; Pm1 is the wet-side pressure of the humidifier before the interval time, with the unit of Pa; Tc2 is the wet-side temperature of the humidifier after the interval time, with the unit of K; Pm2 is the wet-side pressure of the humidifier after the interval time, with the unit of Pa; tm1 is the interval time, with the unit of s.

[0056] In this embodiment, without adding additional components to the fuel cell engine, the online diagnosis of the humidifier is realized. First, the wet side of the humidifier is kept under pressure (i.e., in a steady pressure state, with the gauge pressure not less than 30 KPa (gauge pressure)) through cathode purging, and then the cathode purging is stopped. According to the pressure drop of the wet side of the humidifier caused by leakage to the dry side of the humidifier, the gas leakage rate of the wet side of the humidifier leaking to the dry side of the humidifier is obtained online, and then it is judged whether the humidifier reaches the end of its life, so as to replace the humidifier in time, thereby ensuring the best working state of the fuel cell and preventing the insufficient air intake into it due to the damage of the membrane material of the humidifier from affecting the working life (because of the damage of the membrane material, the low-oxygen cathode exhaust gas from the fuel cell leaks through the membrane material on the wet side of the humidifier to the dry side of the humidifier to form the cathode intake air volume of the fuel cell, resulting in that although the cathode intake air volume meets the conditions during the operation of the fuel cell, the oxygen amount carried by it cannot meet the working requirements), thereby improving the service life of the fuel cell and reducing the use cost and maintenance cost of the fuel cell.

[0057] Since Pm1 and Pm2 in the ideal gas law are absolute pressures, in practical applications, if the value detected by the pressure sensor is gauge pressure, it needs to be converted to absolute pressure; if the value detected by the pressure gauge is absolute pressure, no conversion is required. Similarly, since the gauge pressure of the wet side of the humidifier in the pressure-keeping (steady pressure) state is not less than 30 KPa, if the value detected by the pressure gauge is gauge pressure, it is directly judged whether it is lower than 30 KPa. If the value detected by the pressure gauge is absolute pressure, it needs to be converted to gauge pressure before judgment, or it is judged whether it is lower than (30 KPa + atmospheric pressure value) for judgment. The above should all fall within the protection scope of this application. Similarly, since the units of Tc1 and Tc2 in the ideal gas law are K, in practical applications, when the temperature unit detected by the temperature sensor is °C, it needs to be converted to the unit of K; when the temperature range detected by the temperature sensor is K, no conversion is required. Similarly, for the interval time, it can be converted as needed according to the conversion relationship between units, which will not be elaborated here.

[0058] Furthermore, the ideal gas law satisfies:

[0059] Q2 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1 - Qc

[0060] Wherein, Q2 is the revised value of Q1, with the unit of m 3 / s; Qc is the leakage rate of the pipeline where the wet side of the humidifier is located, with the unit of m 3 / s.

[0061] In this embodiment, the accuracy and scientificity of the online diagnosis of the humidifier are improved, and misjudgment caused by pipeline leakage is avoided, making it more scientific, real and reliable. In practical applications, the leakage rate of the pipeline where the wet side of the humidifier is located can be obtained through a test bench or based on empirical values (the main leakage points are the valve parts at the front and rear ends to keep the wet side of the humidifier in a pressure-holding state (or a constant-pressure state) (i.e., the first valve part and the second valve part described below)).

[0062] Further, the cathode purges the fuel cell until the wet side of the humidifier is in a pressure-holding state and at this time the pressure of the wet side of the humidifier is not less than 30 KPa (gauge pressure), which specifically includes the steps:

[0063] Run the air compressor at a preset speed to purge the fuel cell with the cathode, and adjust the opening of the second valve part so that the pressure of the wet side of the humidifier is not less than 30 KPa (gauge pressure) and not greater than 150 KPa (gauge pressure);

[0064] Then gradually open the bypass valve, and at the same time gradually close the second valve part and when the second valve part is in a closed state, the pressure of the wet side of the humidifier is not less than 30 KPa (gauge pressure);

[0065] Then close the air compressor and the first valve part and keep the bypass valve in an open state, and the wet side of the humidifier is in a pressure-holding state and the pressure of the wet side is not less than 30 KPa (gauge pressure); wherein, the air compressor is arranged on the cathode inlet pipeline, the second valve part is arranged on the cathode outlet pipeline and is arranged near the wet side outlet end of the humidifier, and the first valve part is arranged on the cathode outlet pipeline and is arranged between the fuel cell and the humidifier; the bypass valve is arranged on the cathode bypass pipeline, and the cathode bypass pipeline is used to connect the cathode inlet pipeline with the atmospheric environment.

[0066] In this embodiment, while the cathode purge enables the wet side of the humidifier to reach a constant-pressure state, it ensures that the pressure of the wet side of the humidifier is not lower than 30 KPa (gauge pressure), which not only protects the fuel cell from being affected, but also meets the pressure drop requirement of the wet side of the humidifier.

[0067] Further, the steps for obtaining the pressure and temperature of the wet side of the humidifier before and after the interval time when the dry side of the humidifier is connected to the atmospheric environment specifically include:

[0068] Obtain the wet side pressure and wet side temperature of the humidifier before and after the interval time respectively.

[0069] In this embodiment, the wet side pressure and wet side temperature of the humidifier obtained before and after the interval time are after the dry side of the humidifier is connected to the atmospheric environment.

[0070] In other embodiments, different from the above embodiment, the obtaining of the wet side pressure and wet side temperature of the humidifier before and after the interval time when the dry side of the humidifier is connected to the atmospheric environment specifically includes the steps:

[0071] Obtain the wet side pressure and wet side temperature of the humidifier in the pressure holding state; synchronously connect the dry side of the humidifier to the atmospheric environment until the interval time and then obtain the wet side pressure and wet side temperature of the humidifier again.

[0072] In this embodiment, the wet side pressure and wet side temperature of the humidifier obtained before the interval time are before the dry side of the humidifier is not connected to the atmospheric environment; and the wet side pressure and wet side temperature of the humidifier obtained after the interval time are after the dry side of the humidifier is connected to the atmospheric environment.

[0073] In some other embodiments, different from the above embodiment, the obtaining of the wet side pressure and wet side temperature of the humidifier before and after the interval time when the dry side of the humidifier is connected to the atmospheric environment specifically includes the steps:

[0074] Connect the dry side of the humidifier to the atmospheric environment; obtain the wet side pressure and wet side temperature of the humidifier before and after the interval time respectively.

[0075] In this embodiment, the wet side pressure and wet side temperature of the humidifier obtained before and after are obtained after the dry side of the humidifier is connected to the atmospheric environment.

[0076] Further, connect the dry side of the humidifier to the atmospheric environment; when the wet side pressure of the humidifier drops to the first target pressure range, obtain the wet side pressure and wet side temperature of the humidifier, and record the acquisition time t1; when the wet side pressure of the humidifier drops to the second target pressure range, obtain the wet side pressure and wet side temperature of the humidifier again, and record the acquisition time t2; wherein, the difference between the acquisition time t2 and the acquisition time t1 is the interval time.

[0077] In this embodiment, the interval time and the gas leakage rate of the humidifier are obtained through the pressure set value. Of course, in practical applications, the pressure value and the gas leakage rate of the humidifier can also be obtained by setting the interval time. Thereby improving the applicable range of the present application, meeting the gas leakage rate acquisition methods of different humidifiers, and having strong practicability.

[0078] Further, on the basis of any of the above embodiments, the online diagnosis method for the humidifier of the fuel cell system further includes the steps:

[0079] When the gas leakage rate is not greater than the preset failure value, perform the steps of determining that the humidifier is effective and giving a prompt.

[0080] In this embodiment, if the humidifier is effective, a prompt is also given, so as to facilitate the user to know whether the humidifier needs to be replaced. Of course, when the humidifier is effective, a prompt may not be given, and only a prompt for ineffectiveness and the need for replacement is given.

[0081] Further, on the basis of any of the above embodiments, after step S5, the following steps are further included:

[0082] Stop maintaining the fuel cell within the preset temperature range and shut down the accessories of the fuel cell system.

[0083] In this embodiment, after the online judgment of whether the humidifier is effective is completed, the accessories of the fuel cell system (such as components of the thermal management system, valves, humidifiers, etc.) can be shut down, so as to shut down the fuel cell system.

[0084] Further, on the basis of any of the above embodiments, before maintaining the fuel cell within the preset temperature range (i.e., step S1), the following steps are further included: obtaining a shutdown instruction; executing the shutdown purge strategy of the fuel cell.

[0085] In this embodiment, the online diagnosis of the humidifier can be executed together with the shutdown instruction. After the shutdown purge strategy is executed, the online diagnosis step of the humidifier is executed, so as to simplify the control logic of the entire fuel system and be easy to implement. Moreover, the thermal management requirements for shutdown purge and online diagnosis of the humidifier can be the same. The accessories of the fuel system only need to be shut down once when the two requirements are executed sequentially, and the connection is smooth. In practical applications, the online diagnosis step of the humidifier can be executed together with the shutdown instruction according to the set interval time, so as to save the shutdown time and at the same time realize the online diagnosis of the humidifier.

[0086] The present invention also discloses a computer storage medium, which stores multiple instructions, and the instructions are suitable for being loaded and executed by a processor to perform the online diagnosis method of the humidifier of the fuel cell system according to any of the above embodiments.

[0087] As Figure 2 shown, the present invention also discloses an online diagnosis system for a humidifier of a fuel cell system, including:

[0088] Fuel cell A-1, cathode inlet gas pipeline A-2, cathode outlet gas pipeline A-4, cathode bypass pipeline A-5, humidifier C-9, thermal management system A-3 and controller; wherein, the cathode inlet gas pipeline A-2, the dry side of the humidifier C-9, the fuel cell A-1, the wet side of the humidifier C-9, and the cathode outlet gas pipeline A-4 are connected in sequence; the cathode inlet gas pipeline A-2 is provided with an air compressor C-4; a first valve member (equivalent to the fuel cell outlet throttle C-11 in the following text) is provided between the fuel cell A-1 and the wet side of the humidifier C-9; the cathode outlet gas pipeline A-4 is provided with a second valve member (equivalent to the air back pressure valve C-12 in the following text); the cathode inlet gas pipeline A-2 is connected to the atmospheric environment through the cathode bypass pipeline A-5; the thermal management system A-3 is used to adjust the temperature of the fuel cell A-1; the controller is used to execute the fuel cell system humidifier online diagnosis method described in any one of the above embodiments.

[0089] Further, the thermal management system A-3 includes: a cooling pump W-2, a radiator W-3, a heater W-4, and a thermostat W-5; wherein, one end of the cooling pump W-2 is connected to the outlet of the fuel cell A-1, and the other end is respectively connected to one end of the radiator W-3 and one end of the heater W-4, the other end of the heater W-4 is connected to one end of the thermostat W-5, and the other end of the radiator W-3 is connected to the other end of the thermostat W-5; a fuel cell outlet temperature sensor W-1 is provided between the cooling pump W-2 and the outlet of the fuel cell A-1; a fuel cell inlet temperature sensor W-6 is provided between the thermostat W-5 and the inlet of the fuel cell A-1.

[0090] Further, the cathode inlet gas pipeline A-2 is sequentially provided with an air filter C-2 and an intercooler C-5 along the gas flow direction, and both ends of the air compressor C-4 are respectively connected to the air filter C-2 and the intercooler C-5.

[0091] Exemplarily, as Figure 2 shown, a fuel cell system humidifier online diagnosis system includes: a fuel cell A-1, a cathode inlet gas pipeline A-2, a cathode outlet gas pipeline A-4, a cathode bypass pipeline A-5, a humidifier C-9, a thermal management system A-3 and a controller; wherein, the cathode inlet gas pipeline A-2, the dry side of the humidifier C-9, the fuel cell A-1, the wet side of the humidifier C-9, and the cathode outlet gas pipeline A-4 are connected in sequence; the cathode inlet gas pipeline A-2 is provided with an air compressor C-4; a first valve member (i.e., Figure 2 the fuel cell outlet throttle C-11 in Figure 2 is provided between the fuel cell A-1 and the wet side of the humidifier C-9); a second valve member (i.e.,

[0092] The cathode inlet gas pipeline A-2 is connected to the inlet of the cathode of the fuel cell A-1, and is used to input compressed air into the cathode of the fuel cell A-1, so as to supply the oxygen required for the reaction of the fuel cell A-1.

[0093] The humidifier C-9 is used to humidify the air before entering the fuel cell A-1 to adjust the humidity of the oxygen input into the fuel cell A-1, and the air compressor C-4 is used to pressurize the air input from the outside. The air in the cathode inlet gas pipeline A-2 enters the fuel cell A-1 after being humidified by the humidifier C-9.

[0094] As Figure 2 shown, the specific connection relationship of the humidifier online diagnosis system of this fuel cell system is as follows:

[0095] A pressure sensor 1 C-1, an air filter C-2, and a flow and temperature integrated sensor C-3 are provided upstream of the air compressor C-4 on the cathode inlet gas pipeline A-2. The pressure sensor 1 C-1 is arranged at the inlet of the cathode inlet gas pipeline A-2. The air pressure can be detected by the pressure sensor 1 C-1, and the temperature at which water is completely vaporized can be determined by querying the table corresponding to the air pressure and the complete vaporization of water. The input end of the air filter C-2 is connected to the pressure sensor 1 C-1, the output end of the air filter C-2 is connected to the input end of the air compressor C-4, and the air filter C-2 filters the air before entering the air compressor C-4. A flow and temperature integrated sensor C-3 is provided between the air filter C-2 and the air compressor C-4, and the flow and temperature integrated sensor C-3 can monitor the air flow and temperature entering the cathode inlet gas pipeline A-2. The output end of the air compressor C-4 is connected to the input end of the intercooler C-5, and the output end of the intercooler C-5 is connected to the dry side input end of the humidifier C-9. The inlet and outlet of the cathode of the fuel cell A-1 are respectively connected to the dry side output end of the humidifier C-9 and the wet side input end of the humidifier C-9.

[0096] A pressure sensor 2 C-8 is provided between the air intake throttle valve C-7 and the fuel cell A-1, which is used to monitor the dry side pressure of the humidifier C-9. A temperature and pressure integrated sensor C-10 is provided between the fuel cell outlet throttle valve C-11 and the fuel cell A-1, which is used to monitor the wet side pressure and wet side temperature of the humidifier C-9.

[0097] An air back pressure valve C-12 is provided at the wet side output end of the humidifier C-9, which is used to adjust the humidity of the air entering the cathode outlet gas pipeline A-4.

[0098] The thermal management system A-3 includes: a cooling pump W-2, a radiator W-3, a heater W-4, and a thermostat W-5. The inlet of the fuel cell A-1 is connected to the output of the thermostat W-5. The input terminals 1 and 2 of the thermostat W-5 are respectively connected to the output of the radiator W-3 and the output of the heater W-4. The input terminals of the radiator W-3 and the heater W-4 are both connected to the output of the cooling pump W-2. The input terminal of the cooling pump W-2 is connected to the outlet of the fuel cell A-1.

[0099] One end of the cathode bypass pipeline A-5 is connected to the cathode air inlet pipeline A-2, and the other end is connected to the cathode air outlet pipeline A-4, and a bypass valve C-6 is provided on the cathode bypass pipeline A-5. The air in the cathode air inlet pipeline A-2 can be introduced into the cathode air outlet pipeline A-4 through the cathode bypass pipeline A-5, and the residual hydrogen in the cathode air outlet pipeline A-4 can be diluted with air when the fuel cell A-1 is turned on and off, thereby improving safety.

[0100] Exemplarily, a fuel cell system humidifier online diagnosis method based on the above system of the present disclosure includes the steps of:

[0101] (1) During system shutdown, the shutdown purge strategy of fuel cell A-1 is executed. The inlet coolant temperature of fuel cell A-1 is adjusted to Tfc by controlling heater W-4, radiator W-3, and thermostat W-5, 50℃≤Tfc≤70℃, and this temperature is maintained until the shutdown is completed.

[0102] (2) At the same time, the air compressor C-4 is working, and the speed of the air compressor C-4 is Qc, and the cathode of the fuel cell A-1 is purged at a preset speed. At this time, the bypass valve C-6 is closed, the air intake throttle valve C-7 is fully opened, and the first valve member (i.e. Figure 2 The fuel cell outlet throttle valve C-11 in the fuel cell is fully opened, and the second valve member (i.e. Figure 2 The opening of the air back pressure valve C-12 in the fuel cell A-1 is adjusted to maintain the pressure on the cathode side of the fuel cell A-1 at Pc, 30kPa≤Pc≤150kPa (gauge pressure); the air intake temperature is adjusted through the intercooler C-5, and after the cathode purge time tc, 0≤tc≤300 seconds, the tc time is when the fuel cell A-1 is purged to a constant resistance value, that is, the water content inside the fuel cell A-1 remains unchanged;

[0103] (3) Maintain the speed of air compressor C-4 unchanged, and then gradually open the bypass valve C-6 to a certain angle. The angle is calibrated. Different systems have different angles. At the same time, gradually close the air back pressure valve C-12 until the air back pressure valve C-12 is completely closed. At this time, the wet side pressure Pc of the humidifier is ≥30kPa (gauge pressure).

[0104] (4) After step (3), the wet side temperature Tc and pressure Pc0 of the humidifier C-9 are obtained through the temperature and pressure integrated sensor C-10. Then, the air compressor C-4 and the fuel cell outlet throttle valve C-11 are closed, and the bypass valve C-6 is in the open state. The wet side of the humidifier C-9 is in a pressure-holding state and the wet side pressure is not less than 30 KPa (gauge pressure). Meanwhile, the dry side of the humidifier C-9 is connected to the atmospheric environment. When Pc0 drops to the first target pressure range Pm1 (0 < Pm1 ≤ 70 kPa (gauge pressure)), the acquisition moment is recorded as t1.

[0105] (5) After the moment t1, the wet side pressure Pc1 and wet side temperature Tc1 of the humidifier C-9 when the wet side pressure of the humidifier C-9 drops to the first target pressure range are monitored through the temperature and pressure integrated sensor C-10, where 50°C ≤ Tc1 ≤ 70°C. The dry side pressure value Pa1 of the humidifier C-9 is obtained through the pressure sensor two C-8, and Pa1 is generally the atmospheric pressure at this time.

[0106] (6) When the wet side pressure of the humidifier C-9 drops to the second target pressure range Pm2 (0 < Pm2 < 70 kPa (gauge pressure)), the wet side pressure Pc2 and wet side temperature Tc2 of the humidifier C-9 at this time are obtained again, and the acquisition moment is recorded as t2. The temperature change value ΔT1 = Tc2 - Tc1, and the interval time is tm1 = t2 - t1.

[0107] In practical applications, the second target pressure range Pm2 should be less than the first target pressure range Pm1, and the first target pressure range Pm1 should not be greater than the wet side pressure of the humidifier when the cathode purge is until the wet side of the humidifier is in a pressure-holding state. The set value of the wet side pressure of the humidifier when the cathode purge is until the wet side of the humidifier is in a pressure-holding state can be set to any point value or range value not less than 30 KPa.

[0108] (7) According to the ideal gas state equation PV = nRT, the gas leakage rate Q1 (unit: m 3 / s) of the humidifier C-9 can be obtained. Q1 = n * R (Tc1 / Pm1 - Tc2 / Pm2) / tm1, where n is the amount of substance of air, unit: mol; R is the molar gas constant, unit: J / (mol*K). In this embodiment, R = 8.314 J / (mol*K); Tc1 is the wet side temperature of the humidifier C-9 before the interval time, unit: K; Pm1 is the wet side pressure of the humidifier C-9 before the interval time, unit: Pa; Tc2 is the wet side temperature of the humidifier C-9 after the interval time, unit: K; Pm2 is the wet side pressure of the humidifier C-9 after the interval time, unit: Pa; tm1 is the interval time, unit: s.

[0109] The ideal gas law is satisfied:

[0110] Q2 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1 - Qc

[0111] Wherein, Q2 is the revised value of Q1, with the unit of m 3 / s; Qc is the leakage rate of the pipeline where the wet side of the humidifier C-9 is located, with the unit of m 3 / s.

[0112] (8) Set the preset failure value of the gas leakage rate of the humidifier C-9 as Qm. When the gas leakage rate of the humidifier C-9 is greater than Qm, it is determined that the humidifier C-9 fails and an alarm prompt is given, so that the staff can replace the humidifier C-9 in time; when the gas leakage rate is not greater than the preset failure value Qm, it is determined that the humidifier C-9 is effective and a prompt is given.

[0113] The beneficial effects of the present invention are: without additionally increasing the components of the fuel cell engine, an online diagnosis method for the humidifier of the fuel cell system is provided, which is used to online diagnose the gas leakage rate of the humidifier according to the pressure reduction rate by maintaining the pressure on the wet side of the humidifier, and then judge whether the humidifier reaches the end of its life, so as to replace the humidifier in time and improve the life of the fuel cell system.

[0114] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An on-line diagnostic method for a humidifier of a fuel cell system, characterized in that, Including the steps: Maintain the fuel cell within a preset temperature range and perform the following steps: Purge the fuel cell at the cathode until the wet side of the humidifier is in a pressure-maintained state and the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) at this time; Obtain the wet side pressure and wet side temperature of the humidifier before and after the dry side of the humidifier is connected to the atmospheric environment at intervals; Obtain the gas leakage rate of the humidifier according to the ideal gas law; The ideal gas law satisfies: Q1 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1 Q2 = n * R[Tc1 / Pm1 - Tc2 / Pm2] / tm1 - Qc Among them, Q1 is the gas leakage rate of the humidifier, with the unit of m 3 / s; n is the amount of substance of air, with the unit of mol; R is the molar gas constant, with the unit of J / (mol*K); Tc1 is the wet side temperature of the humidifier before the interval time, with the unit of K; Pm1 is the wet side pressure of the humidifier before the interval time, with the unit of Pa; Tc2 is the wet side temperature of the humidifier after the interval time, with the unit of K; Pm2 is the wet side pressure of the humidifier after the interval time, with the unit of Pa; tm1 is the interval time, with the unit of s; Q2 is the revised value of Q1, with the unit of m 3 / s; Qc is the leakage rate of the pipeline where the wet side of the humidifier is located, with the unit of m 3 / s; When the gas leakage rate is greater than the preset failure value, perform the steps: Determine that the humidifier fails and give a prompt.

2. The online diagnostic method for a humidifier of a fuel cell system according to claim 1, wherein The step of purging the fuel cell at the cathode until the wet side of the humidifier is in a pressure-maintained state and the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) specifically includes the steps: Run the air compressor at a preset speed to purge the fuel cell at the cathode, and adjust the opening of the second valve so that the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure) and not greater than 150 KPa (gauge pressure); Then gradually open the bypass valve, and at the same time gradually close the second valve and when the second valve is in a closed state, the pressure on the wet side of the humidifier is not less than 30 KPa (gauge pressure); Then close the air compressor and the first valve and keep the bypass valve in an open state, the wet side of the humidifier is in a pressure-maintained state and the wet side pressure is not less than 30 KPa (gauge pressure); wherein, the air compressor is arranged on the cathode inlet pipeline, the second valve is arranged on the cathode outlet pipeline and is arranged near the wet side outlet end of the humidifier, the first valve is arranged on the cathode outlet pipeline and is arranged between the fuel cell and the humidifier; the bypass valve is arranged on the cathode bypass pipeline, and the cathode bypass pipeline is used to connect the cathode inlet pipeline to the atmospheric environment.

3. The online diagnosis method of the humidifier of the fuel cell system according to claim 1, characterized in that, The step of obtaining the wet side pressure and wet side temperature of the humidifier before and after the dry side of the humidifier is connected to the atmospheric environment at intervals specifically includes the steps: Obtain the wet side pressure and wet side temperature of the humidifier in a pressure-maintained state; synchronously connect the dry side of the humidifier to the atmospheric environment and obtain the wet side pressure and wet side temperature of the humidifier again at the interval time.

4. The online diagnosis method for a humidifier of a fuel cell system according to claim 1, wherein The step of obtaining the wet side pressure and wet side temperature of the humidifier before and after the dry side of the humidifier is connected to the atmospheric environment at intervals specifically includes the steps: Connect the dry side of the humidifier to the atmospheric environment; respectively obtain the wet side pressure and wet side temperature of the humidifier before and after the interval time; or, Connect the dry side of the humidifier to the atmospheric environment; when the wet side pressure of the humidifier drops to the first target pressure range, obtain the wet side pressure and wet side temperature of the humidifier, and record the acquisition time t1; when the wet side pressure of the humidifier drops to the second target pressure range, obtain the wet side pressure and wet side temperature of the humidifier again, and record the acquisition time t2; wherein, the difference between the acquisition time t2 and the acquisition time t1 is the interval time.

5. The online diagnosis method for the humidifier of the fuel cell system according to claim 1, wherein, It further includes the steps of: When the gas leakage rate is not greater than the preset failure value, execute the steps of: determining that the humidifier is effective and giving a prompt; and / or, Stop maintaining the fuel cell within the preset temperature range and shut down the accessories of the fuel cell system. and / or, Before maintaining the fuel cell within the preset temperature range, it further includes the steps of: obtaining a shutdown instruction; executing the shutdown purge strategy of the fuel cell.

6. A computer storage medium, characterized in that, The computer storage medium stores multiple instructions, and the instructions are suitable for being loaded and executed by a processor to perform the online diagnosis method for a humidifier of a fuel cell system according to any one of claims 1-5.

7. An online diagnostic system for a humidifier of a fuel cell system, characterized in that, It includes: A fuel cell, a cathode inlet pipeline, a cathode outlet pipeline, a cathode bypass pipeline, a humidifier, a thermal management system, and a controller; Wherein, the cathode inlet pipeline, the dry side of the humidifier, the fuel cell, the wet side of the humidifier, and the cathode outlet pipeline are connected in sequence; an air compressor is provided on the cathode inlet pipeline; a first valve member is provided between the fuel cell and the wet side of the humidifier; a second valve member is provided on the cathode outlet pipeline; the cathode inlet pipeline is connected to the atmospheric environment through the cathode bypass pipeline; the thermal management system is used to adjust the temperature of the fuel cell; the controller is used to execute the online diagnosis method for a humidifier of a fuel cell system according to any one of claims 1-5.

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