A device and method for detecting the sealing performance of a fuel cell air system

Abstract

The present invention relates to the field of detecting the sealing of fuel cell air pipelines, and discloses a device and method for detecting the sealing of a fuel cell air system, comprising an intake throttle, a humidifier, a fuel cell stack, a tail exhaust throttle, and several groups of sensors. The intake throttle is connected to the gas inlet of the fuel cell stack through the humidifier, and the tail exhaust throttle is connected to the gas outlet of the fuel cell stack through the humidifier. Sensors are respectively arranged on the connecting pipe between the intake throttle and the humidifier, on the connecting pipe between the humidifier and the gas outlet of the fuel cell stack, and on the connecting pipe between the humidifier and the tail exhaust throttle, and the sensors are used to detect gas. The present invention can realize online judgment of whether the humidifier has internal leakage problems by using the value collected by the oxygen concentration sensor and the fuel cell stack operating current. At the same time, it can also judge whether the throttle, humidifier, and pipeline in the battery air system have external leakage problems by changing the pressure value in the pipeline and the value collected by the oxygen concentration sensor after shutdown.

Description

Technical Field

[0001] The present invention relates to the field of detecting the sealing performance of fuel cell air pipelines, and in particular to a device and method for detecting the sealing performance of a fuel cell air system. Background Art

[0002] The air source in the fuel cell engine is mainly provided by the air compressor. The air in the air pipeline is generally humidified by a humidifier before entering the fuel cell stack for reaction. The phenomenon of reduced air flow into the fuel cell stack will cause the performance of the fuel cell stack to decline. At the same time, the sealing of the air circulation branch will also have a certain impact on the protection of the fuel cell stack performance after shutdown.

[0003] Therefore, whether each component has external or internal leakage during normal operation or after shutdown of the fuel cell stack will affect the stable operation of the engine. However, there is still a lack of online methods to detect whether the components on the air circulation branch of the fuel cell engine have internal or external leakage. Summary of the Invention

[0004] In order to solve the problem that the existing technology cannot detect the sealing of components on the air circulation branch online, and thus cannot determine whether the components are leaking, the present invention provides a fuel cell air system sealing detection device and method.

[0005] The technical solutions of the present invention are as follows:

[0006] A device for detecting the sealing of a fuel cell air system comprises: an intake throttle, a humidifier, a fuel cell stack, a tail exhaust throttle and several groups of sensors, wherein the intake throttle is connected to the gas inlet of the fuel cell stack through the humidifier, and the tail exhaust throttle is connected to the gas outlet of the fuel cell stack through the humidifier, and the sensors are respectively arranged on the connecting pipeline between the intake throttle and the humidifier, the connecting pipeline between the humidifier and the gas outlet of the fuel cell stack, and the connecting pipeline between the humidifier and the tail exhaust throttle, and the sensors are used to detect gas.

[0007] Furthermore, the sensor includes two groups of temperature sensors, two groups of pressure sensors and an oxygen concentration sensor. The temperature sensors are used to collect the temperature of the gas, the pressure sensors are used to collect the pressure value of the gas, and the oxygen concentration sensor is used to detect the oxygen concentration in the gas.

[0008] Furthermore, a group of temperature sensors and a group of pressure sensors are provided on the connecting pipeline between the intake throttle and the humidifier, which are used to collect the temperature and pressure values ​​of the gas before entering the humidifier. A group of temperature sensors and a group of pressure sensors are provided on the connecting pipeline between the humidifier and the gas outlet of the fuel cell stack, which are used to collect the temperature and pressure values ​​of the gas before entering the humidifier. The oxygen concentration sensor is provided on the connecting pipeline between the humidifier and the tail exhaust throttle, and the oxygen concentration sensor detects the oxygen concentration of the gas at the outlet of the humidifier.

[0009] Furthermore, an intercooler is included, and the intercooler is used to reduce the temperature of the gas. The cooled gas enters the humidifier through the intake throttle.

[0010] Furthermore, an air compressor is included, which heats and pressurizes the gas. The air compressor is connected to the intercooler and the intake throttle valve in sequence.

[0011] Furthermore, an air filter is included, which is used to remove particulate impurities in the gas. The air filter, air compressor, intercooler and intake throttle are connected in sequence.

[0012] A method for detecting the sealing performance of a fuel cell air system, comprising:

[0013] S1: By detecting the operating status of the battery stack, it is determined whether the battery stack is in normal working state or shutdown / stop state, and the atmospheric pressure in the environment is detected at the same time;

[0014] S2: By collecting the oxygen content of the air before entering the stack and the oxygen consumption when entering the stack under normal working conditions, the actual oxygen content of the air when leaving the stack is calculated, and then compared with the oxygen content of the air collected by the oxygen concentration sensor. The comparison result is used to determine whether the humidifier in the fuel cell air system has internal leakage;

[0015] S3: By collecting the pressure value of the dry side of the humidifier and the pressure value at the air outlet of the stack after the stack is shut down, and comparing the value collected by the pressure sensor with the atmospheric pressure value in the environment after the stack is shut down for a period of time, it is determined by the comparison results whether there is leakage in the intake throttle, tail exhaust throttle, humidifier and pipeline in the fuel cell air system.

[0016] Furthermore, the S2 includes the following:

[0017] S21: The oxygen content in the air is V, as determined by the atmospheric pressure table. According to the ideal gas state equation:

[0018] pV=nRT (1);

[0019] The temperature and pressure values ​​are obtained by the temperature sensor and pressure sensor at the humidifier inlet, and the actual oxygen flow rate in the air before entering the pile is corrected to Q in-stack ,

[0020] In formula (1), p is the pressure, V is the gas volume, T is the temperature, n is the amount of gas, and R is the molar gas constant;

[0021] S22: By obtaining the actual load current I of the fuel cell stack under normal working conditions, the actual oxygen consumption of the fuel cell stack is calculated as:

[0022] Q stack =MO2*n*I / 4F*10^(-8) (2);

[0023] In formula (2), MO2 is the molar mass of oxygen, n is the number of cells in the stack, I is the load current, and F is the Faraday constant;

[0024] S23: The oxygen flow rate when air leaves the stack is obtained by the above formula (1) and formula (2): Q1 out-stack =Q in-stack -Q stack , combined with formula (1) and the temperature and pressure values ​​obtained by the temperature sensor and pressure sensor at the air outlet of the stack, the actual oxygen flow rate in the air after leaving the stack is corrected to Q2 out-stack , calculate the oxygen content in the air at this time is V2;

[0025] S24: The oxygen content of the air collected by the oxygen concentration sensor is set to V3, and V3 is compared with V2 in S23. If V2 is less than V3, it indicates that the humidifier has an internal leak, otherwise it indicates that the humidifier is working normally.

[0026] Furthermore, by judging the size of the pressure sensor collected value within 3 hours of the fuel cell stack shutdown and the atmospheric pressure value in the environment, if the pressure sensor collected value is less than the atmospheric pressure value in the environment and the oxygen concentration sensor collects 0, it indicates that the air pipeline is sealed normally; otherwise, it indicates that the pipeline and / or the intake throttle, tail exhaust throttle, and humidifier have sealing failures.

[0027] Furthermore, the S1 detects the atmospheric pressure in the environment through the fuel cell controller.

[0028] The beneficial effects of the present invention include at least: the present invention can realize online judgment of whether the humidifier has internal leakage through the values ​​collected by the oxygen concentration sensor and the operating current of the fuel cell stack, and further achieve the effect of analyzing the performance of the humidifier and the fuel cell stack; at the same time, it can also judge whether the throttle, humidifier and pipeline in the battery air system have external leakage problems through the changes in the pressure value in the pipeline after shutdown and the collected value of the oxygen concentration sensor, and further achieve the purpose of avoiding the formation of hydrogen-oxygen interface in the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of the fuel cell air system sealing detection device of the present invention.

[0030] Figure 2 It is a schematic flow chart of the steps for detecting the sealing performance of the fuel cell air system of the present invention.

[0031] Figure 3 This is a schematic flow chart of the specific steps for detecting the sealing performance of the fuel cell air system of the present invention.

[0032] in:

[0033] 1-Intake throttle;

[0034] 2-Humidifier;

[0035] 3- battery stack;

[0036] 4-Tail exhaust throttle;

[0037] 5-Sensor;

[0038] 501-temperature sensor; 502-pressure sensor; 503-oxygen concentration sensor;

[0039] 6-Intercooler;

[0040] 7-Air compressor;

[0041] 8-Air filter. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Combine Figure 1-2As shown, the present invention discloses a device for detecting the sealing of a fuel cell air system, comprising: an intake throttle 1, a humidifier 2, a fuel cell stack 3, a tail exhaust throttle 4 and several groups of sensors 5, wherein the intake throttle 1 is connected to the gas inlet of the fuel cell stack 3 through the humidifier 2, and the tail exhaust throttle 4 is connected to the gas outlet of the fuel cell stack 3 through the humidifier 2, and the sensors 5 are respectively arranged on the connecting pipeline between the intake throttle 1 and the humidifier 2, the connecting pipeline between the humidifier 2 and the gas outlet of the fuel cell stack 3, and the connecting pipeline between the humidifier 2 and the tail exhaust throttle 4, and the sensors 5 are used to detect gas.

[0044] Furthermore, the sensor 5 includes two groups of temperature sensors 501, two groups of pressure sensors 502 and an oxygen concentration sensor 503. The temperature sensor 501 is used to collect the temperature of the gas, the pressure sensor 502 is used to collect the pressure value of the gas, and the oxygen concentration sensor 503 is used to detect the oxygen concentration in the gas.

[0045] Furthermore, a group of temperature sensors 501 and a group of pressure sensors 502 are provided on the connecting pipeline between the intake throttle valve 1 and the humidifier 2, which are used to collect the temperature and pressure values ​​of the gas before entering the humidifier 2. A group of temperature sensors 501 and a group of pressure sensors 502 are provided on the connecting pipeline between the humidifier 2 and the gas outlet of the fuel cell 3, which are used to collect the temperature and pressure values ​​of the gas before entering the humidifier 2. The oxygen concentration sensor 503 is provided on the connecting pipeline between the humidifier 2 and the tail exhaust throttle valve 4, and the oxygen concentration sensor 503 detects the oxygen concentration of the gas at the outlet of the humidifier 2.

[0046] A group of temperature sensors 501 and a group of pressure sensors 502 are provided on the connecting pipeline between the intake throttle valve 1 and the humidifier 2, which are used to collect the temperature and pressure values ​​of the air before it enters the humidifier 2. A group of temperature sensors 501 and a group of pressure sensors 502 are provided on the connecting pipeline between the humidifier 2 and the gas outlet of the fuel cell 3, which are used to collect the temperature and pressure values ​​of the air when the air reacts through the fuel cell 3 and flows out from the gas outlet of the fuel cell 3 to the pipeline connected to the humidifier 2. What is collected here is the temperature and pressure value of the air that is about to enter the humidifier 2 on the pipeline connecting the fuel cell 3, the humidifier 2 and the tail exhaust throttle valve. After the unreacted gas, water vapor and part of the liquid water in the fuel cell enter the humidifier 2, the dry side air is humidified. The oxygen concentration sensor 503 at the wet outlet position of the humidifier 2 detects the oxygen concentration of the gas at the outlet of the humidifier 2. The dry side air refers to the air entering from the intake throttle valve 1.

[0047] Furthermore, an intercooler 6 is included, and the intercooler 6 is used to reduce the temperature of the gas. The cooled gas enters the humidifier through the intake throttle valve 1.

[0048] Furthermore, an air compressor 7 is included, which heats and pressurizes the gas. An intercooler 6 reduces the temperature of the gas at the rear end of the air compressor 7. The air compressor 7 is connected to the intercooler 6 and the intake throttle valve 1 in sequence.

[0049] Furthermore, an air filter 8 is included, and the air filter 8 is used to remove particulate impurities in the gas. The air filter 8, the air compressor 7, the intercooler 6 and the intake throttle valve 1 are connected in sequence.

[0050] A method for detecting the sealing performance of a fuel cell air system, comprising:

[0051] S1: By detecting the operating status of the battery stack, it is determined whether the battery stack is in normal working state or shutdown / stop state, and the atmospheric pressure in the environment is detected at the same time;

[0052] S2: By collecting the oxygen content of the air before entering the stack and the oxygen consumption when entering the stack under normal working conditions, the actual oxygen content of the air when leaving the stack is calculated, and then compared with the oxygen content of the air collected by the oxygen concentration sensor. The comparison result is used to determine whether the humidifier in the fuel cell air system has internal leakage;

[0053] S3: By collecting the pressure value of the dry side of the humidifier and the pressure value at the air outlet of the stack after the stack is shut down, and comparing the value collected by the pressure sensor with the atmospheric pressure value in the environment after the stack is shut down for a period of time, it is determined by the comparison results whether there is leakage in the intake throttle, tail exhaust throttle, humidifier and pipeline in the fuel cell air system.

[0054] Furthermore, the S2 includes the following:

[0055] S21: The oxygen content in the air is V, as determined by the atmospheric pressure table. According to the ideal gas state equation:

[0056] pV=nRT (1);

[0057] The temperature and pressure values ​​are obtained by the temperature sensor and pressure sensor at the humidifier inlet, and the actual oxygen flow rate in the air before entering the pile is corrected to Q in-stack ,

[0058] In formula (1), p is the pressure, V is the gas volume, T is the temperature, n is the amount of gas, and R is the molar gas constant;

[0059] S22: By obtaining the actual load current I of the fuel cell stack under normal working conditions, the actual oxygen consumption of the fuel cell stack is calculated as:

[0060] Q stack =MO2*n*I / 4F*10^(-8) (2);

[0061] In formula (2), MO2 is the molar mass of oxygen, n is the number of cells in the stack, I is the load current, and F is the Faraday constant;

[0062] S23: The oxygen flow rate when air leaves the stack is obtained by the above formula (1) and formula (2): Q1 out-stack =Q in-stack -Q stack , combined with formula (1) and the temperature and pressure values ​​obtained by the temperature sensor and pressure sensor at the air outlet of the stack, the actual oxygen flow rate in the air after leaving the stack is corrected to Q2 out-stack , calculate the oxygen content in the air at this time is V2;

[0063] S24: The oxygen content of the air collected by the oxygen concentration sensor is set to V3, and V3 is compared with V2 in S23. If V2 is less than V3, it indicates that the humidifier has an internal leak, otherwise it indicates that the humidifier is working normally.

[0064] Furthermore, by judging the size of the pressure sensor collected value within 3 hours of the fuel cell stack shutdown and the atmospheric pressure value in the environment, if the pressure sensor collected value is less than the atmospheric pressure value in the environment and the oxygen concentration sensor collects 0, it indicates that the air pipeline is sealed normally; otherwise, it indicates that the pipeline and / or the intake throttle, tail exhaust throttle, and humidifier have sealing failures.

[0065] The detection device provided by the present invention includes two groups of pressure sensors. After the fuel cell stack is shut down, the pressure value inside the fuel cell air system is collected by the pressure sensor, and the collected pressure value is compared with the atmospheric pressure in the environment to determine whether the air path pipeline is sealed normally. Here, for the pressure value collected by the fuel cell air system, it is only necessary to take the collection value of any one group of the two groups of pressure sensors. The air path pipeline refers to the pipeline used to connect components and transport gas in the detection device.

[0066] Furthermore, the S1 detects the atmospheric pressure in the environment through the fuel cell controller.

[0067] Combine Figure 3 As shown, the present invention determines whether the fuel cell stack is in a normal working state or a shutdown / stop state by detecting the operating state of the engine.

[0068] When the stack is in normal operation, the atmospheric pressure in the environment is detected by the fuel cell controller, and the oxygen content in the air is obtained from the atmospheric pressure value table as V. When the air gas is heated and pressurized by the air compressor, the mass flow rate of oxygen in the air will change. Therefore, according to the ideal gas state equation pV = nRT, and the temperature and pressure values ​​at the humidifier inlet, the actual oxygen flow rate in the air when entering the stack can be corrected to Q. in-stack .

[0069] Then, the fuel cell controller can know the actual load current of the fuel cell stack when the engine is running, which is I. According to the load current value of the fuel cell stack, the actual gas consumption of the fuel cell stack can be obtained. stack =MO2*n*I / 4F*10^(-8), unit is kg / s, where MO2 is the molar mass of oxygen, n is the number of cells in the stack, I is the load current, and F is the Faraday constant; the oxygen content in the gas after the air leaves the stack, Q1, can be obtained. out-stack =Q in-stack -Q stac k. When air passes through the stack and reacts, its temperature and pressure change. This can be corrected based on the ideal gas state equation PV = nRT and the stack air outlet temperature and pressure value to obtain the actual oxygen flow rate in the air after leaving the stack, which is Q2 out-stack The oxygen content in the air at this time is calculated using the modified value as V2. The oxygen content V2 in the air at this time is compared with the oxygen concentration V3 collected by the oxygen concentration sensor. If the stack oxygen concentration V2 is less than the oxygen concentration V3 collected by the oxygen concentration sensor, it indicates that air is leaking from the dry side of the humidifier to the wet outlet, causing the oxygen concentration sensor to collect a value higher than that at the stack outlet. After long-term operation, the increase in cross-talk leakage may lead to insufficient stack gas and performance degradation.

[0070] When the fuel cell stack is detected to be shut down, the fuel cell controller detects the gas pressure in the environment. After the shutdown, it collects the pressure value on the dry side of the humidifier and the pressure value at the air outlet of the fuel cell stack to determine the difference between the value collected by the pressure sensor and the atmospheric pressure value in the environment within 3 hours of the shutdown. If the value collected by the pressure sensor is less than the pressure value in the environment and the oxygen concentration sensor is zero, it indicates that the air pipeline is sealed normally and there is no major leakage. Otherwise, it indicates that the pipeline or throttle may have a sealing failure problem.

[0071] The unit of oxygen flow rate Q in the present invention is g / s, which represents the mass of oxygen passing through per unit time; the oxygen content V, also known as the oxygen content, represents the volume occupied by oxygen in the current volume of gas. The oxygen flow rate is converted to oxygen content to facilitate comparison with the value collected by the oxygen concentration sensor.

[0072] The present invention can realize online judgment of whether the humidifier has internal leakage through the values ​​collected by the oxygen concentration sensor and the operating current of the fuel cell stack, and further achieve the effect of analyzing the performance of the humidifier and the fuel cell stack; at the same time, it can also judge whether the throttle, humidifier and pipeline in the battery air system have external leakage problems through the changes in the pressure value in the pipeline after shutdown and the collected value of the oxygen concentration sensor, and further achieve the purpose of avoiding the formation of hydrogen-oxygen interface in the fuel cell stack.

[0073] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for detecting the leak tightness of a fuel cell air system, characterized in that: include: An intake throttle, a humidifier, a fuel cell stack, a tail exhaust throttle, and several groups of sensors, wherein the intake throttle is connected to the gas inlet of the fuel cell stack through the humidifier, and the tail exhaust throttle is connected to the gas outlet of the fuel cell stack through the humidifier. The sensors are respectively arranged on the connecting pipes between the intake throttle and the humidifier, the connecting pipes between the humidifier and the gas outlet of the fuel cell stack, and the connecting pipes between the humidifier and the tail exhaust throttle, and the sensors are used to detect gas; The sensors include two sets of temperature sensors, two sets of pressure sensors and an oxygen concentration sensor. The temperature sensors are used to collect the temperature of the gas, the pressure sensors are used to collect the pressure value of the gas, and the oxygen concentration sensor is used to detect the oxygen concentration in the gas. Wherein, a group of temperature sensors and a group of pressure sensors are provided on the connecting pipeline between the intake throttle and the humidifier, for collecting the temperature and pressure values ​​of the gas before entering the humidifier; a group of temperature sensors and a group of pressure sensors are provided on the connecting pipeline between the humidifier and the gas outlet of the fuel cell stack, for collecting the temperature and pressure values ​​of the gas before entering the humidifier; the oxygen concentration sensor is provided on the connecting pipeline between the humidifier and the tail exhaust throttle, and the oxygen concentration sensor detects the oxygen concentration of the gas at the humidifier outlet; The intercooler is used to reduce the temperature of the gas, and the cooled gas enters the humidifier through the intake throttle valve; Among them, it also includes an air compressor, which heats and pressurizes the gas. The air compressor is connected to the intercooler and the intake throttle in sequence.

2. A fuel cell air system sealing detection device according to claim 1, characterized in that: The air filter is also included, and the air filter is used to remove particulate impurities in the gas. The air filter, the air compressor, the intercooler and the intake throttle are connected in sequence.

3. A method for detecting the sealing performance of a fuel cell air system, comprising the detection device according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: By detecting the operating status of the battery stack, it is determined whether the battery stack is in normal working state or shutdown / stop state, and the atmospheric pressure in the environment is detected at the same time; S2: By collecting the oxygen content of the air before entering the stack and the oxygen consumption when entering the stack under normal working conditions, the actual oxygen content of the air when leaving the stack is calculated, and then compared with the oxygen content of the air collected by the oxygen concentration sensor. The comparison result is used to determine whether the humidifier in the fuel cell air system has internal leakage; S3: By collecting the pressure value of the dry side of the humidifier and the pressure value at the air outlet of the stack after the stack is shut down, and comparing the value collected by the pressure sensor with the atmospheric pressure value in the environment after the stack is shut down for a period of time, it is determined by the comparison results whether there is leakage in the intake throttle, tail exhaust throttle, humidifier and pipeline in the fuel cell air system.

4. The method for detecting the sealing performance of a fuel cell air system according to claim 3, wherein: The S2 includes the following: S21: The oxygen content in the air is V, as determined by the atmospheric pressure table. According to the ideal gas state equation: pV=nRT (1); The temperature and pressure values ​​are obtained by the temperature sensor and pressure sensor at the humidifier inlet, and the actual oxygen flow rate in the air before entering the pile is corrected to Q in-stack , where p is the pressure, V is the gas volume, T is the temperature, n is the amount of gas, and R is the molar gas constant; S22: By obtaining the actual load current I of the fuel cell stack under normal working conditions, the actual oxygen consumption of the fuel cell stack is calculated as: Q stack =M O2 *n*I / 4F*10^(-8) (2); In formula (2), M O2 is the molar mass of oxygen, n is the number of cells in the stack, I is the load current, and F is the Faraday constant; S23: The oxygen flow rate when air leaves the stack is obtained by the above formula (1) and formula (2): Q1 out-stack =Q in-stack -Q stack , combined with formula (1) and the temperature and pressure values ​​obtained by the temperature sensor and pressure sensor at the air outlet of the stack, the actual oxygen flow rate in the air after leaving the stack is corrected to Q2 out-stack , calculate the oxygen content in the air at this time is V2; S24: The oxygen content of the air collected by the oxygen concentration sensor is set to V3, and V3 is compared with V2 in S23. If V2 is less than V3, it indicates that the humidifier has an internal leak, otherwise it indicates that the humidifier is working normally.

5. The method for detecting the sealing performance of a fuel cell air system according to claim 4, wherein: By judging the difference between the value collected by the pressure sensor and the atmospheric pressure value in the environment within 3 hours of the fuel cell stack shutdown, if the value collected by the pressure sensor is less than the atmospheric pressure value in the environment and the oxygen concentration sensor is 0, it indicates that the air pipeline is sealed normally. Otherwise, it indicates that there is leakage in the pipeline and / or the intake throttle, tail exhaust throttle, and humidifier.

6. The method for detecting the sealing performance of a fuel cell air system according to claim 3, wherein: The S1 detects the atmospheric pressure in the environment through the fuel cell controller.

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