A fuel cell anode gas component real-time detection device

Abstract

The present application relates to a kind of fuel cell anode gas component real-time detection device, be arranged in the water separator rear end of hydrogen supply system, the detection device includes condenser, dryer, hydrogen concentration analyzer and controller;Mixed gas exported from the water separator rear end of hydrogen supply system is cooled down in turn by condenser, residual water vapor is separated by dryer, then input to the hydrogen concentration analyzer to measure the hydrogen volume percentage in mixed gas after discharge;First pressure sensor, temperature and humidity integrated sensor are arranged on the pipeline between the water separator and condenser, and the controller is calculated to obtain the mixed gas component of the anode outlet of electric pile according to the measurement data of first pressure sensor, temperature and humidity integrated sensor and hydrogen concentration analyzer.Compared with prior art, the present application has the advantages of high real-time and high accuracy.

Description

Technical Field

[0001] This invention relates to the field of fuel cell measurement technology, and in particular to a real-time detection device for fuel cell anode gas components. Background Technology

[0002] Hydrogen fuel cells generate electricity through the chemical reaction of hydrogen and oxygen. They feature negative emissions, zero pollution, and high energy efficiency, making them a promising direction for future new energy vehicle power. Hydrogen supply systems with recirculation components can improve hydrogen utilization. However, because nitrogen-based gases diffuse from the proton exchange membrane to the anode in the cathode chamber, the hydrogen concentration in the anode chamber decreases, leading to a drop in the stack's output voltage and, in severe cases, even damaging the stack's lifespan.

[0003] Hydrogen venting via a venting valve can increase the hydrogen concentration at the fuel cell stack anode. However, current venting strategies mostly employ fixed-period venting, which is insufficient to handle varying operating conditions. If anode gas composition information is available, it can be directly used as the trigger signal for the venting valve. However, due to the presence of water vapor, a single hydrogen concentration analyzer is insufficient to accurately measure the hydrogen concentration at the fuel cell stack anode.

[0004] Therefore, there is an urgent need to design a device that can detect the composition of the anode gas in the fuel cell stack in real time, so as to provide guidance for the control of the hydrogen venting valve, thereby maintaining the hydrogen concentration at the anode of the fuel cell stack within a reasonable range and ensuring the output characteristics and lifespan of the fuel cell stack. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a real-time detection device for fuel cell anode gas components with high real-time performance and high accuracy.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] This invention provides a real-time detection device for anode gas components in a fuel cell, which is installed at the downstream end of the water separator in a hydrogen supply system. The detection device includes a condenser, a dryer, a hydrogen concentration analyzer, and a controller.

[0008] The mixed gas output from the water separator of the hydrogen supply system is cooled by a condenser and separated from residual water vapor by a dryer before being fed into the hydrogen concentration analyzer to measure the volume percentage of hydrogen in the mixed gas before being discharged.

[0009] A first pressure sensor and a temperature and humidity sensor are installed on the pipeline between the water separator and the condenser. The controller calculates the mixed gas composition at the anode outlet of the fuel cell stack based on the measurement data from the first pressure sensor, the temperature and humidity sensor, and the hydrogen concentration analyzer.

[0010] Preferably, the gas components of the mixed gas flowing into the detection device include hydrogen, nitrogen and water vapor, and the gas components of the mixed gas flowing out of the dryer include hydrogen and nitrogen.

[0011] Preferably, the controller calculates the mixed gas composition at the anode outlet of the fuel cell stack based on the measurement data from the first pressure sensor, the integrated temperature and humidity sensor, and the hydrogen concentration analyzer. The calculation expressions are as follows:

[0012]

[0013]

[0014]

[0015] in: These represent the volume fractions of hydrogen, nitrogen, and water vapor in the mixed gas at the anode outlet of the fuel cell stack, respectively; p1 is the total pressure of the mixed gas measured by the first pressure sensor; RH is the relative humidity of water vapor measured by the integrated temperature and humidity sensor; and T1 is the temperature of the mixed gas measured by the integrated temperature and humidity sensor. p represents the volume fraction of hydrogen in the mixed gas at the downstream end of the dryer, as measured by a hydrogen concentration analyzer. sat (T1) is the saturated vapor pressure of water at temperature T1.

[0016] Preferably, a second pressure sensor and a temperature sensor are installed on the pipeline between the dryer and the hydrogen concentration analyzer. The second pressure sensor and the temperature sensor are respectively connected to the controller to detect the dynamic information of the gas entering the front end of the hydrogen concentration analyzer.

[0017] Preferably, the condenser discharges its internal condensate through a built-in drain valve.

[0018] Preferably, the drying cotton in the dryer is replaced periodically.

[0019] Preferably, the output pipe of the hydrogen concentration analyzer is also equipped with a flow control valve to control the flow rate of the incoming mixed gas.

[0020] Preferably, a flow sensor is also installed on the pipeline between the dryer and the hydrogen concentration analyzer, and the controller controls the flow control valve through the measurement data of the flow sensor to control the flow rate of the mixed gas flowing in.

[0021] Preferably, the flow rate of the controlled inflow of mixed gas is less than a set value.

[0022] Preferably, the output of the controller is connected to the hydrogen discharge valve located at the rear end of the water separator of the hydrogen supply system to control the hydrogen discharge operation, thereby increasing the hydrogen concentration at the anode of the fuel cell stack.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1) By pre-installing a dryer in the detection pipeline, the presence of water vapor prevents the single hydrogen concentration analyzer from accurately measuring the hydrogen concentration of the fuel cell stack anode mixed gas, thus enabling real-time results of the fuel cell stack anode gas composition.

[0025] 2) The condenser is designed to reduce the temperature of the high-temperature mixed gas at the anode of the fuel cell stack to meet the requirements of the hydrogen analyzer; and a drain valve is installed in the condenser to drain the liquid water condensed in the condenser pipes and prevent blockage of the pipes.

[0026] 3) Regularly replacing the drying cotton in the dryer ensures the accuracy of the hydrogen analyzer.

[0027] 4) Control the flow rate of the anode gas composition real-time detection device by using a flow control valve, and keep the flow rate of this branch as low as possible to reduce the impact of the anode gas composition real-time detection device on the fuel cell system.

[0028] 5) This invention can realize the real-time detection of the gas concentration of each component at the anode of a fuel cell, which has a guiding role in the control of the hydrogen supply system of the fuel cell. On the one hand, it can verify the accuracy of the hydrogen concentration observer at the anode of the fuel cell; on the other hand, it can provide guidance for the calibration of hydrogen discharge control of the hydrogen supply system of the fuel cell, especially to cope with the changing operating conditions, thereby maintaining the hydrogen concentration at the anode of the fuel cell stack within a reasonable range, and ensuring the output characteristics and life of the fuel cell stack. Attached Figure Description

[0029] Figure 1 This is a general layout diagram of the real-time detection device for anode gas components in this invention;

[0030] Figure 2 This is a schematic diagram of the real-time detection device for anode gas components according to the present invention;

[0031] Attached figures: ① heat exchanger, ② drain valve, ③ dryer, ④ hydrogen concentration analyzer, ⑤ flow control valve, ⑥ controller. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] Example

[0034] like Figure 1 and Figure 2 As shown, this embodiment provides a real-time detection device for the anode gas components of a fuel cell, which is installed downstream of the water separator in the hydrogen supply system. The device includes a condenser ①, a drain valve ②, a dryer ③, a hydrogen concentration analyzer ④, a flow control valve ⑤, and a controller ⑥. The sensors include two pressure sensors, one flow sensor, one temperature sensor, and one temperature and humidity sensor.

[0035] The condenser ① is used to reduce the temperature of the high-temperature mixed gas at the anode of the fuel cell stack to meet the requirements of the hydrogen analyzer ④.

[0036] Drain valve ② is used to drain the liquid water condensed in the condenser pipes to prevent blockage of the pipes.

[0037] Dryer ③ is used to absorb water vapor in the mixed gas. To ensure the accuracy of the hydrogen analyzer ④, the drying cotton in dryer ③ needs to be replaced regularly.

[0038] Flow control valve ⑤ is used to control the flow rate of the anode gas composition real-time detection device and to keep the flow rate of this branch as low as possible to reduce the impact of the anode gas composition real-time detection device on the fuel cell system.

[0039] The pressure sensor and the integrated temperature and humidity sensor are located at the front end of condenser ①, and the measured values ​​are recorded as p1, T1, and RH, respectively. The flow sensor, pressure sensor, and temperature sensor are located at the rear end of dryer ③, and the measured values ​​are recorded as... p2, T2.

[0040] The controller ⑥ collects sensor information to calculate the composition of the mixed gas at the anode outlet of the fuel cell stack and issues commands to actuators such as the hydrogen discharge valve.

[0041] Fuel cell anode gas composition detection:

[0042] Assumptions: The gas composition at the fuel cell anode outlet is hydrogen, nitrogen, and water vapor; that is, the gas composition flowing into the fuel cell anode gas composition real-time monitoring device is hydrogen, nitrogen, and water vapor. (The air at the fuel cell cathode contains 21% oxygen and 78% nitrogen, and oxygen reacts extensively at the cathode; therefore, the diffusion of oxygen across the proton exchange membrane is negligible compared to the diffusion of nitrogen across the membrane.) The dryer completely absorbs the water vapor in the anode gas composition real-time monitoring device, meaning the gas composition flowing into the hydrogen concentration analyzer is hydrogen and nitrogen.

[0043] Expression of gas partial pressure of the mixture at the front end of the condenser:

[0044]

[0045] Where: p an_outThe total pressure of the mixed gas at the anode outlet of the fuel cell stack (kPa), i.e., the sensor measurement value p1 (kPa); Hydrogen partial pressure at the anode outlet of the fuel cell stack (kPa); Nitrogen partial pressure at the anode outlet of the fuel cell stack (kPa); Partial pressure of water vapor at the anode outlet of the fuel cell stack (kPa).

[0046] Expression of water vapor partial pressure before condenser:

[0047]

[0048] Among them: relative humidity of water vapor at the anode outlet of the RH fuel cell stack, i.e., the value measured by the integrated temperature and humidity sensor; Saturated vapor pressure (kPa) of the outlet water at the anode of the fuel cell stack; T an_out The temperature (K) of the mixed gas at the anode outlet of the fuel cell stack is T1, which is the value measured by the temperature and humidity sensor.

[0049] Expression of saturated vapor pressure of water:

[0050]

[0051] The composition of hydrogen and nitrogen gas remains unchanged before and after passing through the dryer, and their partial pressures are as follows:

[0052]

[0053] in: The volume fraction of hydrogen in the mixed gas at the back end of the dryer.

[0054] Partial pressures of hydrogen and nitrogen at the anode outlet of the fuel cell stack:

[0055]

[0056]

[0057] The composition of the mixed gas at the anode outlet of the fuel cell stack was determined by measurements taken from pressure sensors, temperature and humidity sensors, and hydrogen concentration analyzers as follows:

[0058]

[0059]

[0060]

[0061] in: The mole fractions of hydrogen, nitrogen, and water vapor in the mixed gas at the anode outlet of the fuel cell stack are also equal to their volume fractions.

[0062] The method of this invention solves the problem that a single hydrogen concentration analyzer is difficult to accurately measure the hydrogen concentration of the fuel cell stack anode mixed gas. It can obtain real-time results of the fuel cell stack anode gas composition and can be used to verify the accuracy of anode hydrogen concentration observers and anode nitrogen concentration observers, as well as guide hydrogen removal strategies.

[0063] The fuel cell anode gas component detection proposed in this invention can be directly code-built and automatically compiled on the Simulink platform, and the program can be burned into an embedded system, which can be directly applied to fuel cell test benches and vehicles.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A real-time detection device for anode gas components in a fuel cell, installed at the downstream end of the water separator in a hydrogen supply system, characterized in that, The detection device includes a condenser, a dryer, a hydrogen concentration analyzer, and a controller; The mixed gas output from the water separator of the hydrogen supply system is cooled by a condenser and separated from residual water vapor by a dryer before being fed into the hydrogen concentration analyzer to measure the volume percentage of hydrogen in the mixed gas before being discharged. A first pressure sensor and a temperature and humidity sensor are installed on the pipeline between the water separator and the condenser. The controller calculates the mixed gas composition at the anode outlet of the fuel cell stack based on the measurement data from the first pressure sensor, the temperature and humidity sensor, and the hydrogen concentration analyzer. The gas components of the mixed gas flowing into the detection device include hydrogen, nitrogen and water vapor, and the gas components of the mixed gas flowing out of the dryer include hydrogen and nitrogen. The controller calculates the mixed gas composition at the anode outlet of the fuel cell stack based on the measurement data from the first pressure sensor, the integrated temperature and humidity sensor, and the hydrogen concentration analyzer. The calculation expressions are as follows: in: , , These represent the volume fractions of hydrogen, nitrogen, and water vapor in the mixed gas at the anode outlet of the fuel cell stack, respectively. The total pressure of the air-fuel mixture as measured by the first pressure sensor. The relative humidity of water vapor measured by the integrated temperature and humidity sensor. The temperature of the air-fuel mixture is measured by an integrated temperature and humidity sensor. This represents the volume fraction of hydrogen in the mixed gas at the rear end of the dryer, as measured by a hydrogen concentration analyzer. For temperature The saturated vapor pressure of water at that time.

2. The real-time detection device for fuel cell anode gas components according to claim 1, characterized in that, A second pressure sensor and a temperature sensor are installed on the pipeline between the dryer and the hydrogen concentration analyzer. The second pressure sensor and the temperature sensor are respectively connected to the controller to detect the dynamic information of the gas entering the front end of the hydrogen concentration analyzer.

3. The real-time detection device for fuel cell anode gas components according to claim 1, characterized in that, The condenser discharges its internal condensate through a built-in drain valve.

4. The real-time detection device for fuel cell anode gas components according to claim 1, characterized in that, The drying cotton in the dryer needs to be replaced periodically.

5. The real-time detection device for fuel cell anode gas components according to claim 1, characterized in that, The output pipe of the hydrogen concentration analyzer is also equipped with a flow control valve to control the flow rate of the mixed gas flowing in.

6. The real-time detection device for fuel cell anode gas components according to claim 5, characterized in that, A flow sensor is also installed on the pipeline between the dryer and the hydrogen concentration analyzer. The controller controls the flow control valve based on the measurement data from the flow sensor to control the flow rate of the mixed gas flowing in.

7. A real-time detection device for fuel cell anode gas components according to claim 6, characterized in that, The flow rate of the mixed gas entering the system is less than a set value.

8. The real-time detection device for fuel cell anode gas components according to claim 1, characterized in that, The output of the controller is connected to the hydrogen discharge valve installed at the rear end of the water separator of the hydrogen supply system to control the hydrogen discharge operation, thereby increasing the hydrogen concentration at the anode of the fuel cell stack.

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