A hydrogen circulation structure of a fuel cell system and a temperature and humidity parameter control method thereof

Abstract

The present application relates to the technical field of fuel cell, and discloses a hydrogen circulation structure of fuel cell system and a temperature and humidity parameter control method thereof, the hydrogen circulation structure of fuel cell system comprises a hydrogen circulation management unit, the hydrogen circulation management unit is connected with a cell stack through an out-stack main pipeline and an in-stack main pipeline, a hydrogen circulation branch of the anode out-stack main pipeline is provided with a circulating cooler, a gas-liquid separation liquid discharger, a hydrogen heat exchanger and a circulating pump, a cooling liquid pump is arranged on a total pipeline of a cooling circulation unit, the cooling liquid pump outlet is divided into a first branch and a second branch, the first branch is provided with a first regulating valve, a heater and a hydrogen heat exchanger, the second branch is provided with a second regulating valve and a radiator cell stack, a third branch is connected with the pipeline between the first branch and the second branch and the cooling liquid pump inlet at one end and connected with a cooling liquid tank at the other end.The present application can avoid the liquid water from entering the hydrogen circulation pump to cause the pump assembly damage, improve the fuel cell stability and solve other problems.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, and particularly relates to a hydrogen circulation structure of a fuel cell system and a temperature and humidity parameter control method thereof. BACKGROUND

[0002] A fuel cell is an electrochemical reaction device for directly converting chemical energy into electrical energy. A proton exchange membrane fuel cell is a fuel cell with the largest development scale at present, and has the characteristics of high energy conversion efficiency, low working temperature, small noise and zero pollution, and can be used in vehicles, aerospace, fixed power stations and underwater devices and other scenes. In the working process of the proton exchange membrane fuel cell, hydrogen is introduced into the anode of the cell stack, and air or oxygen is introduced into the cathode. Hydrogen generates protons and electrons under the action of anode catalyst, protons reach the cathode in a hydrated state through a proton exchange membrane, and electrons reach the cathode through an external circuit. Oxygen combines with protons and electrons to generate water and release heat under the action of cathode catalyst. When the electrons flow from the anode to the cathode through the external circuit, an electric current is generated to supply power to the load.

[0003] In the working process of the proton exchange membrane fuel cell system, pure hydrogen is introduced into the anode in excess. After the electrode reaction, there is unreacted hydrogen remaining. If it is directly discharged into the atmosphere, it will cause environmental pollution and waste of energy, and has great safety hazards. The hydrogen supply and management system of the proton exchange membrane fuel cell is mainly used for delivering hydrogen to the anode of the cell stack, and recycling the unreacted hydrogen to the anode of the cell stack to improve the hydrogen utilization rate and the efficiency of the cell stack. Due to the generation of water and heat during the internal electrochemical reaction process of the cell stack, the hydrogen circulation process will redistribute the water and heat to a certain extent. Therefore, the hydrogen circulation process plays an important role in the fuel utilization rate, durability and internal water balance of the entire system, is a key technology of the fuel cell, and directly affects the performance and reliability.

[0004] The main problems of the hydrogen circulation system of the fuel cell at present are: 1. The frequency of the variable load of the fuel cell is relatively large, and the heat and water produced by the cell stack change in the variable load process, which affects the heat and water of the hydrogen circulation process, so the hydrogen circulation system requires strong adaptability and controllability in the variable load process of the fuel cell; 2. The water content of the exhaust gas carried by the anode of the fuel cell stack is relatively large, and the relative humidity of the exhaust gas is relatively high, so the water is easy to condense in the circulation process, and the accumulated condensate causes the pipeline resistance to be relatively large, affecting the flowability of the circulating fluid, and the condensate entering the circulating pump causes the service life of the pump components to decrease rapidly, and if the condensate is not properly managed, the condensate will enter the cell stack, causing the anode of the cell stack to be flooded; 3. The operating parameters and control parameters of the anode circulation process are coupled together, the temperature and humidity parameters of the circulation loop are not actively controlled, and are often in a passive state, so when the fuel cell has abnormal phenomena, it cannot be actively intervened; 4. The relative humidity of the hydrogen circulation loop of the cell stack has a large hysteresis, and other interference factors in the dynamic process can easily cause large fluctuations in the relative humidity and dew point temperature, and further cause the water and heat management of the cell stack to be unbalanced. SUMMARY

[0005] The present application aims to provide a fuel cell system hydrogen circulation structure and a temperature and humidity parameter control method thereof to solve the above-mentioned problems of the prior art.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] A fuel cell system hydrogen circulation structure, comprising: a cell stack unit, a hydrogen circulation management unit, and a cooling circulation unit.

[0008] The hydrogen circulation management unit comprises an anode exhaust stack main pipeline, an anode stack inlet main pipeline, a gas source branch, a hydrogen circulation branch, and an exhaust branch; one end of the anode exhaust stack main pipeline is connected with the anode exhaust port of the cell stack unit, and the other end is divided into the hydrogen circulation branch and the exhaust branch; one end of the anode stack inlet main pipeline is connected with the anode stack inlet port of the cell stack unit, and the other end is connected with the convergence point of the hydrogen circulation branch and the gas source branch; a circulating cooler, a gas-liquid separation liquid discharger, a hydrogen heat exchanger, and a circulating pump are sequentially arranged on the hydrogen circulation branch.

[0009] The cooling circulation unit comprises one main pipeline and three branches, a cooling liquid pump is arranged on the main pipeline, the outlet end of the cooling liquid pump is divided into a first branch and a second branch, the first branch and the second branch are connected at the pipeline convergence point of the inlet end of the cooling liquid pump; the first branch is provided with a first adjusting valve, a heater, and a hydrogen heat exchanger; the second branch is provided with a second adjusting valve and a radiator, and the second branch is also connected with the cell stack of the cell stack unit; one end of the third branch is connected with the pipeline between the convergence point of the first branch and the second branch and the inlet of the cooling liquid pump, and the other end is connected with a cooling liquid tank.

[0010] The principle and advantages of the present scheme are: in actual application, by setting a circulating cooler, a gas-liquid separation liquid discharger, a hydrogen heat exchanger and a circulating pump in the hydrogen circulation branch, the wet hydrogen gas containing moisture and heat at the anode out-of-stack port of the cell stack unit is condensed, liquid is discharged and heated, the circulating gas is first condensed to reduce the moisture content of the gas, then gas-liquid separation and liquid discharge are performed, and liquid water is discharged to avoid the problems of large pipeline resistance drop and poor gas flowability caused by liquid water accumulation in the hydrogen circulation process. Finally, by increasing the temperature to reduce the relative humidity, the gas flow stability is improved, and the problem of pump assembly damage caused by liquid water entering the hydrogen circulation pump is avoided. The present application also has strong anti-interference ability. When the battery stack operating current, voltage and external environment temperature change, the hydrogen circulation loop temperature and relative humidity change. The controller can immediately issue adjustment instructions to the circulating cooler and heater, so that the temperature and relative humidity quickly tend to the target value, and the fuel cell system has strong adaptability to variable load conditions and can improve the stability of the fuel cell system under variable load conditions and complex operating environments.

[0011] Preferably, as an improvement, a first relative humidity sensor, a first temperature sensor and a first pressure sensor are arranged on the anode-in-stack main pipeline; a second pressure sensor and a second temperature sensor are arranged on the anode-out-stack main pipeline; a third temperature sensor is arranged on the pipeline between the heater and the hydrogen heat exchanger; a fourth temperature sensor is arranged on the pipeline connected to the inlet of the cell stack unit; and a fifth temperature sensor is arranged on the pipeline between the cell stack outlet and the junction of the first branch and the second branch.

[0012] Technical effect: By arranging multiple temperature and humidity sensors and pressure sensors, the overall situation of multiple pipelines is realized.

[0013] Preferably, as an improvement, the first relative humidity sensor is used to detect the relative humidity of the anode-in-stack gas as a first relative humidity value, the first temperature sensor is used to detect the temperature of the anode-in-stack gas as a first temperature value, and the first pressure sensor is used to detect the pressure of the anode-in-stack gas as a first pressure value; the second pressure sensor is used to detect the pressure of the anode-out-stack gas as a second pressure value, and the second temperature sensor is used to detect the temperature of the anode-out-stack gas as a second temperature value; the third temperature sensor is used to detect the medium temperature of the pipeline section between the heater and the hydrogen heat exchanger as a third temperature value; the fourth temperature sensor is used to detect the temperature of the cell stack-in cooling liquid as a fourth temperature value; and the fifth temperature sensor is used to detect the temperature of the cell stack-out cooling liquid as a fifth temperature value.

[0014] Technical effect: It is convenient to adjust the temperature, pressure, humidity and the like under multiple working conditions.

[0015] Preferably, as an improvement, the battery stack unit comprises a battery stack, a cathode inlet stack pipeline, a cathode inlet stack port, a cathode outlet stack port, a cathode outlet stack pipeline, a cooling liquid inlet stack port, a cooling liquid outlet stack port, an anode inlet stack port, an anode outlet stack port, a load line, and a voltage collection line; the cathode reaction gas in the cathode inlet stack pipeline enters the battery stack through the cathode inlet stack port, the anode reaction gas in the anode inlet stack pipeline enters the battery stack through the anode inlet stack port, and the battery stack cooling liquid of the cooling circulation unit enters the battery stack through the cooling liquid inlet stack port; the cooling liquid outlet stack port is used to take out the battery stack cooling liquid, the cathode outlet stack port is used to discharge the remaining cathode reaction gas of the battery stack, and the anode outlet stack port is used to discharge the remaining anode reaction gas of the battery stack.

[0016] Technical effects: The cathode and anode reaction gases inside the battery stack perform electrochemical reactions, and the reaction process generates electric energy, heat energy, and water; the electric energy is consumed by the load, the heat energy is taken out from the cooling liquid outlet stack port by the battery stack cooling liquid, the remaining cathode reaction gas of the battery stack is discharged from the cathode outlet stack port into the cathode outlet stack pipeline, and the remaining anode reaction gas of the battery stack is discharged from the anode outlet stack port into the anode outlet stack pipeline, so as to facilitate the normal operation of the battery stack unit.

[0017] Preferably, as an improvement, the system further comprises an electronic control unit, which comprises a data collector, a controller, a load, and a control component; the data collector is used to collect, convert, and transmit the battery stack voltage signals in real time; the controller comprises a first temperature control unit TC1, a third temperature control unit TC3, and a first relative humidity control unit HC1, and the controller operates and sends instructions to the system according to a preset control method; the load is used to execute the controller instructions to consume the electric energy generated by the battery stack; and the control component is an auxiliary functional component of the electronic control unit.

[0018] Technical effects: Through the electronic control unit, it is convenient to adjust according to different use conditions to adapt to various working conditions.

[0019] Preferably, as an improvement, the first pressure value, the second temperature value, and the second pressure value are system operation state monitoring values, and the first temperature value, the third temperature value, the fourth temperature value, the fifth temperature value, and the first relative humidity value are control target variables.

[0020] Technical effects: The temperature of the hydrogen circulation loop is convenient to control.

[0021] Preferably, as an improvement, a gas source hydrogen pressure stabilizing device is arranged on the gas source branch, and the gas source hydrogen pressure stabilizing device is closed-loop controlled with the first pressure value.

[0022] Technical effects: The hydrogen pressure stabilizing device is convenient to control the hydrogen supply amount through interlocking control with the first pressure value.

[0023] Preferably, as an improvement, the exhaust branch is provided with an exhaust device, which performs exhaust action intermittently according to the exhaust and drainage requirements of the battery stack.

[0024] Technical effects: By setting the exhaust device, the excess water and gas can be easily discharged.

[0025] Preferably, as an improvement, the circulating cooler comprises a wind-cooled or liquid-cooled type.

[0026] Technical effects: The wind-cooled system is suitable for extremely low temperature scenarios, because the liquid-cooled system may freeze the pipes and cooling liquid in extremely low temperature environment, and even break the pipes. The wind-cooled system can effectively avoid such adverse phenomena and ensure normal operation of the system. When the heat generation is small, the wind-cooled system is suitable. According to the actual use, the cooling method is selected to facilitate the normal operation of the system.

[0027] A temperature and humidity parameter control method of a hydrogen circulation structure of a fuel cell system, comprising:

[0028] Collecting the current value and voltage value of the battery stack operation;

[0029] According to the current value and voltage value, the hydrogen circulation pump rotating speed, temperature set value and relative humidity set value are determined;

[0030] The temperature value is judged. When the difference between the temperature set value and the detected value is greater than the minimum threshold value, the controller TC1 output value is obtained through the PI or PID control law;

[0031] The difference between the controller TC1 output value and the third temperature value is judged. When the difference between the controller TC1 output value and the third temperature value is greater than the minimum threshold value, the controller TC3 output value is obtained through the PI or PID control law;

[0032] The heater power is adjusted according to the controller TC3 instruction;

[0033] The difference between the controller TC1 output value and the third temperature value is judged. When the difference between the controller TC1 output value and the third temperature value is less than or equal to the minimum threshold value, the difference between the temperature set value and the detected value is judged. When the difference between the temperature set value and the detected value is less than or equal to the minimum threshold value, the heater maintains the state;

[0034] The difference between the relative humidity set value and the detected value is judged. When the difference between the relative humidity set value and the detected value is greater than the minimum threshold value, the controller HC1 output value is obtained through the PI or PID control law;

[0035] The circulating cooler cooling medium flow is adjusted according to the controller HC1 instruction;

[0036] If the difference between the relative humidity set value and the detected value is less than or equal to the minimum threshold value, the result is yes, and the cooler maintains the state;

[0037] Otherwise, return to the first step. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A schematic diagram of a hydrogen circulation structure of a fuel cell system;

[0039] Figure 2 An example control block diagram of the temperature and humidity parameter control of the hydrogen circulation loop.

[0040] Figure 3 An example control logic flow chart of the temperature and humidity parameter control of the hydrogen circulation loop. DETAILED DESCRIPTION

[0041] The following is further described in detail through specific embodiments:

[0042] The reference signs in the drawings of the specification include: a cell stack unit 100, a hydrogen circulation management unit 200, a cooling circulation unit 300, an electric control unit 400, a cell stack 101, a cathode inlet stack pipeline 110, a cathode inlet stack port 111, a cathode outlet stack port 112, a cathode outlet stack pipeline 113, a cooling liquid inlet stack port 120, a cooling liquid outlet stack port 121, an anode inlet stack port 130, an anode outlet stack port 131, an anode outlet stack main pipeline 210, a second pressure sensor 211, a second temperature sensor 212, a hydrogen circulation branch 220, a circulation cooler 221, a gas-liquid separation liquid discharger 222, a hydrogen heat exchanger 223, a circulation pump 224, an exhaust branch 230, an exhaust device 231, a gas source branch 240, a gas source hydrogen pressure stabilizing device 241, an anode inlet stack main pipeline 250, a first relative humidity sensor 251, a first temperature sensor 252, a first pressure sensor 253, a main pipeline 310, a cooling liquid pump 311, a first branch 320, a first regulating valve 321, a heater 322, a third temperature sensor 323, a second branch 330, a second regulating valve 331, a radiator 332, a fourth temperature sensor 333, a fifth temperature sensor 334, a third branch 340, a cooling liquid tank 341, a data collector 410, a controller 420, a load 430, a control assembly 440.

[0043] The embodiment is basically as shown in the accompanying drawings: Figure 1

[0044] A hydrogen circulation structure of a fuel cell system, comprising: a cell stack unit 100, a hydrogen circulation management unit 200, a cooling circulation unit 300, and an electric control unit 400;

[0045] ​The battery stack unit 100 comprises a battery stack 101, a cathode inlet stack pipe 110, a cathode inlet stack port 111, a cathode outlet stack port 112, a cathode outlet stack pipe 113, a cooling liquid inlet stack port 120, a cooling liquid outlet stack port 121, an anode inlet stack port 130, an anode outlet stack port 131, a load line, and a voltage collection line. During the operation of the fuel cell system, the cathode reaction gas of the cathode inlet stack pipe 110 enters the battery stack 101 through the cathode inlet stack port 111, the anode reaction gas of the anode inlet stack pipe enters the battery stack 101 through the anode inlet stack port 130, and the battery stack cooling liquid of the cooling circulation unit 300 enters the battery stack 101 through the cooling liquid inlet stack port 120. The cathode and anode reaction gases inside the battery stack 101 perform electrochemical reactions, and the reaction process generates electric energy, heat energy and water. The electric energy is consumed by the load 430, the heat energy is taken out from the cooling liquid outlet stack port 121 by the battery stack cooling liquid, the battery stack cathode reaction residual gas is discharged from the cathode outlet stack port 112 into the cathode outlet stack pipe 113, and the battery stack anode reaction residual gas is discharged from the anode outlet stack port 131 into the anode outlet stack pipe, so as to facilitate the normal operation of the battery stack 101.

[0046] In order to recycle the battery stack anode gas and effectively manage water and gas, the hydrogen circulation management unit 200 comprises an anode outlet stack main pipe 210, an anode inlet stack main pipe 250, a gas source branch 240, a hydrogen circulation branch 220 and an exhaust branch 230. One end of the anode outlet stack main pipe 210 is connected to the anode outlet stack port 131 of the battery stack unit 100, and the other end is divided into the hydrogen circulation branch 220 and the exhaust branch 230. One end of the anode inlet stack main pipe 250 is connected to the anode inlet stack port 130 of the battery stack unit 100, and the other end is connected to the junction of the hydrogen circulation branch 220 and the gas source branch 240. The hydrogen circulation branch 220 is sequentially provided with a circulating cooler 221, a gas-liquid separation liquid discharger 222, a hydrogen heat exchanger 223 and a circulating pump 224.

[0047] During the operation of the fuel cell system, the remaining gas from the anode outlet pipe of the cell stack after the anode reaction of the cell stack is divided into two paths, one of which enters the hydrogen circulation branch 220, and the other of which enters the exhaust branch 230; the anode outlet wet hydrogen gas containing water and heat that enters the hydrogen circulation branch 220 first flows through the circulating cooler 221 to be cooled, and part of the gaseous water is condensed into liquid water during the cooling process; the liquid water flows with the gas to the gas-liquid separation liquid discharger 222, and the gas and the liquid water are separated in the gas-liquid separation liquid discharger 222; the liquid water is discharged from the hydrogen circulation loop, and the gas flows through the hydrogen heat exchanger 223 to be heated, and then is combined with the hydrogen from the gas source branch 240, and is transported into the anode inlet manifold 250 by the circulating pump 224, and then enters the cell stack 101; the gas source branch 240 is provided with a gas source hydrogen pressure stabilizing device 241, the gas source hydrogen pressure stabilizing device 241 is closed-loop controlled with the first pressure value, and the hydrogen pressure stabilizing device controls the hydrogen supply amount through interlocking control with the first pressure value; the part entering the exhaust branch 230 is intermittently discharged through the exhaust device 231 when the system issues an exhaust instruction; the exhaust branch 230 is provided with the exhaust device 231, which facilitates the discharge of excess water and gas; and the exhaust device 231 performs the exhaust action intermittently according to the exhaust and drainage requirements of the cell stack.

[0048] By setting the condensation, liquid discharge and heating functions, the circulating gas is first condensed to reduce the water content of the gas, then gas-liquid separation and liquid discharge are performed, and the liquid water is discharged to avoid the problems of large pipeline resistance drop and poor gas flowability caused by the accumulation of liquid water in the hydrogen circulation process, and finally the relative humidity is reduced by heating to improve the gas flow stability and avoid the problem of pump assembly damage caused by the entry of liquid water into the hydrogen circulating pump 224.

[0049] The cooling circulation unit 300 includes one main path 310 and three branches, the main path 310 is provided with a cooling liquid pump 311, the outlet end of the cooling liquid pump 311 is divided into a first branch 320 and a second branch 330, the first branch 320 is provided with a first adjusting valve 321, a heater 322 and a hydrogen heat exchanger 223; the first branch 320 and the second branch 330 are combined at the inlet end of the cooling liquid pump 311; the second branch 330 is provided with a second adjusting valve 331 and a radiator 332, and the second branch 330 is also connected to the cell stack 101; one end of a third branch 340 is connected to the pipeline between the combination point of the first branch 320 and the second branch 330 and the inlet of the cooling liquid pump 311, and the other end is connected to a cooling liquid tank 341.

[0050] During the operation of the fuel cell system, the first branch 320 of the cell stack cooling liquid medium carries the heat generated by the cell stack into the hydrogen heat exchanger 223 to exchange heat with the circulating hydrogen gas on the cold side and the hot side, the cold side of the hydrogen heat exchanger 223 flows through the circulating wet hydrogen gas, and the hot side flows through the cell stack cooling liquid from the cooling circulation unit 300; the heater 322 serves as an auxiliary heat source to warm the first branch 320 medium; the heat generated by the cell stack is transferred or consumed by the radiator 332 of the second branch 330; the circulating cooler 221 includes air-cooled or liquid-cooled.

[0051] The electric control unit 400 includes a data collector 410, a controller 420, a load 430, and a control component 440; the data collector 410 is used to collect, convert, and transmit the voltage signal of the cell stack 101 in real time; the controller 420 includes a first temperature control unit TC1, a third temperature control unit TC3, and a first relative humidity control unit HC1, and the controller 420 operates and sends instructions according to a preset control method; the load 430 is used to execute the instructions of the controller 420 to consume the electric energy generated by the cell stack 101; and the control component 440 is an auxiliary functional component of the electric control unit 400.

[0052] The first relative humidity sensor 251, the first temperature sensor 252, and the first pressure sensor 253 are arranged on the anode inlet stack pipeline 250; the second pressure sensor 211 and the second temperature sensor 212 are arranged on the anode outlet stack pipeline 210; the third temperature sensor 323 is arranged on the pipeline between the heater 322 and the hydrogen heat exchanger 223; the fourth temperature sensor is arranged on the pipeline connected to the inlet of the cell stack unit 100, and the fifth temperature sensor 334 is arranged on the pipeline between the outlet of the cell stack and the junction of the first branch 320 and the second branch 330.

[0053] The first relative humidity sensor 251 is used to detect the relative humidity of the anode inlet gas as a first relative humidity value, the first temperature sensor 252 is used to detect the temperature of the anode inlet gas as a first temperature value, and the first pressure sensor 253 is used to detect the pressure of the anode inlet gas as a first pressure value; the second pressure sensor 211 is used to detect the pressure of the anode outlet gas as a second pressure value, and the second temperature sensor 212 is used to detect the temperature of the anode outlet gas as a second temperature value; the third temperature sensor 323 is used to detect the temperature of the medium in the pipeline section between the heater 322 and the hydrogen heat exchanger 223 as a third temperature value; the fourth temperature sensor is used to detect the temperature of the cell stack inlet cooling liquid as a fourth temperature value; and the fifth temperature sensor 334 is used to detect the temperature of the cell stack outlet cooling liquid as a fifth temperature value.

[0054] The first pressure value, the second temperature value, and the second pressure value are used as system operation state monitoring values, and the first temperature value, the third temperature value, the fourth temperature value, the fifth temperature value, and the first relative humidity value are used as control target variables.

[0055] In the temperature control process of the battery stack cooling loop, the fourth temperature value or the fifth temperature value is associated with the cooling source flow of the radiator 332. In the same working condition, when the cooling source flow increases, the fourth temperature value or the fifth temperature value decreases, and when the cooling source flow decreases, the fourth temperature value or the fifth temperature value increases.

[0056] In the temperature difference control process of the battery stack cooling loop, the difference between the fifth temperature value and the fourth temperature value is the battery stack temperature difference, and the battery stack temperature difference is associated with the rotating speed of the cooling liquid pump 311. In the same working condition, the greater the rotating speed of the cooling liquid pump 311, the smaller the battery stack temperature difference, and the smaller the rotating speed of the cooling liquid pump 311, the greater the battery stack temperature difference.

[0057] In the temperature control process of the hydrogen circulation loop, the first temperature value and the third temperature value are associated with the heating power of the heater 322. When the heat exchange loop is disturbed, the third temperature value changes, and the response rate is relatively fast. The first temperature value also has a certain lagging change, and the response rate is relatively slow. According to the change of the third temperature value, the heating power of the heater 322 is controlled in a large range in advance, and then the heating power of the heater 322 is controlled in a small range according to the difference between the first temperature and the given value, so that the first temperature is relatively constant. The output of the first temperature control unit is the given value of the third temperature controller, and the output of the third temperature unit is directly sent to the heater 322 to change the heating power.

[0058] The main disturbances of the heat exchange loop include: the change of the battery stack current and the change of the cooling liquid temperature, the periodic change of the cooling liquid temperature caused by the temperature control process of the radiator 332, and the change of the cooling liquid flow caused by the battery stack temperature difference control process; the battery stack inlet temperature and the inlet relative humidity are in a coupled state, when the battery stack inlet temperature changes, the relative humidity changes accordingly. In order to control the relative humidity in different working conditions, the inlet relative humidity and the cooling medium flow of the cooler are controlled by PI or PID closed loop control, and the inlet temperature is treated as a disturbance. When the inlet temperature changes during the variable load process or other dynamic processes, the relative humidity is still controllable. By associating the cooler with the target relative humidity and associating the heating device with the target temperature, the temperature and the relative humidity can be independently controlled according to the demand, indirectly realizing the quantitative adjustment of the water content in the hydrogen circulation loop according to the operation condition of the battery stack 101, achieving the purpose of active control of the water content of the anode inlet gas of the battery stack, avoiding the problems of water flooding or over-drying of the battery stack 101, and improving the stability and reliability of the fuel cell system.

[0059] When the battery stack 101 runs current, voltage changes, or external environment temperature changes, etc., the hydrogen circulation branch 220 temperature and relative humidity change, which is transmitted to the controller 420 to send adjustment instructions to the cooler and heater 322 in real time, so that the temperature and relative humidity quickly tend to target values, that is, the adjustment is enabled. Therefore, the application has strong anti-interference ability, strong adaptability to fuel cell variable load working conditions, and can improve the stability of the fuel cell system under variable load working conditions and complex operating environment.

[0060] A temperature and humidity parameter control method for a hydrogen circulation structure of a fuel cell system, as shown in Figure 2

[0061] The hydrogen circulation loop temperature and humidity parameter control system includes a temperature control main loop C10, a temperature control auxiliary loop C20, and a relative humidity control loop C30. The temperature control main loop C10 is a custom control system, and the temperature control auxiliary loop C20 is a follow-up system. The set value of the auxiliary controller C22 changes with the output of the main controller C12.

[0062] In the temperature control process, the anode stack inlet temperature set value and the anode stack inlet temperature sensor feedback signal are compared in the comparison mechanism C11, and the result is transmitted to the anode stack inlet temperature control unit TC1. The output of the control unit TC1 is input to the comparison mechanism C21, which also receives the feedback value from the auxiliary circulating water temperature sensor. The output of the comparison mechanism C21 is input to the auxiliary circulating water temperature control unit TC3, and the output of the control unit TC3 is input to the heater 322. The heater 322 performs corresponding actions according to the input, and the result is fed back to the hydrogen circulation management unit 200 and the cooling circulation unit 300, thereby changing the controlled anode stack inlet temperature and gradually tending to the set value.

[0063] The controlled temperature change is input as a disturbance to the hydrogen circulation loop in the relative humidity control process, causing the relative humidity value of the hydrogen circulation loop to change. The relative humidity value is fed back to the comparison mechanism C31 through the first relative humidity sensor 251. The comparison mechanism C31 compares the relative humidity set value with the feedback value, and the comparison result is transmitted to the relative humidity control unit HC1. The output of the control unit HC1 is input to the circulating cooler 221, and the circulating cooler 221 changes its flow according to the input instruction. The result causes the relative humidity of the hydrogen circulation branch 220 to change and gradually tend to the set value.

[0064] As shown in Figure 3 ​As shown, after the system starts, the running current and voltage of the battery stack 101 are collected, and the temperature, pressure, and relative humidity of the cooling circulation unit 300 and the hydrogen circulation unit are collected; the minimum threshold of the difference between the target value and the detected value is determined according to the running current and voltage of the battery stack 101, the temperature setting value Ts1*, the relative humidity setting value RH1*, and the target value; when the difference between the temperature setting value Ts1* and the detected value Ts1 is greater than the minimum threshold, the controller TC1 compares the difference between the target temperature value and the detected value with the minimum threshold, and obtains the output value of the controller TC1 through the PI or PID control law, otherwise, the program returns to the starting step; whether the difference between the output value signal of the controller TC1 and the third temperature value is greater than the minimum threshold, if yes, the controller TC3 compares the difference between the temperature setting value and the detected value with the minimum threshold, and obtains the output value of the controller TC3 through the PI or PID control law, and the power of the heater 322 is adjusted according to the instruction of the controller TC3, if no, the program returns to the starting step; then, whether the difference between the output value of the controller TC1 and the third temperature value is less than or equal to the minimum threshold, if yes, whether the difference between the temperature setting value Ts1* and the detected value Ts1 is less than or equal to the minimum threshold, if yes, the heater 322 maintains the state, if no, the program returns to the starting step.

[0065] When the difference between the relative humidity setting value and the detected value is greater than the minimum threshold, the controller HC1 compares the difference between the temperature setting value and the detected value with the minimum threshold, and obtains the output value of the controller HC1 through the PI or PID control law, the cooling medium flow of the circulating cooler 221 is adjusted according to the instruction of the controller HC1, and whether the difference between the relative humidity setting value RH1* and the detected value RH1 is less than or equal to the minimum threshold is continuously judged, if yes, the cooler maintains the state, if no, the program returns to the starting step.

[0066] The above is only an embodiment of the present application, and the specific technical solutions and / or common knowledge of characteristics in the scheme are not described in detail. It should be noted that, for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like in the description can be used to explain the content of the claims.

Claims

1. A hydrogen circulation structure for a fuel cell system, characterized in that, include: Battery stack unit, hydrogen circulation management unit, cooling circulation unit; The hydrogen circulation management unit includes an anode outlet main pipeline, an anode inlet main pipeline, a gas source branch, a hydrogen circulation branch, and an exhaust branch. One end of the anode outlet main pipeline is connected to the anode outlet of the battery stack unit, and the other end is divided into a hydrogen circulation branch and an exhaust branch. One end of the anode inlet main pipeline is connected to the anode inlet of the battery stack unit, and the other end is connected to the junction of the hydrogen circulation branch and the gas source branch. A circulating cooler, a gas-liquid separator drainer, a hydrogen heat exchanger, and a circulating pump are sequentially installed on the hydrogen circulation branch. The cooling circulation unit includes a main line and three branch lines. A coolant pump is installed on the main line. The outlet of the coolant pump is divided into a first branch and a second branch. The first branch and the second branch merge at the inlet of the coolant pump. The first branch is equipped with a first regulating valve, a heater, and a hydrogen heat exchanger. The second branch is equipped with a second regulating valve and a radiator. The second branch is also connected to the battery stack of the battery stack unit. One end of the third branch is connected to the pipeline between the junction of the first branch and the second branch and the inlet of the coolant pump, and the other end is connected to the coolant tank. A first relative humidity sensor and a first temperature sensor are installed on the anode feed gas main. The first relative humidity sensor is used to detect the relative humidity of the anode feed gas as a first relative humidity value, and the first temperature sensor is used to detect the temperature of the anode feed gas as a first temperature value. A third temperature sensor is installed on the pipeline between the heater and the hydrogen heat exchanger. The third temperature sensor is used to detect the medium temperature of the pipeline section between the heater and the hydrogen heat exchanger as the third temperature value. It also includes an electronic control unit, which includes a data acquisition unit, a controller, a load, and control components. The data acquisition unit is used to acquire, convert, and transmit the battery stack voltage signal in real time. The controller includes a first temperature control unit TC1, a third temperature control unit TC3, and a first relative humidity control unit HC1. The controller performs calculations and sends instructions to the system according to a preset control method. The load is used to execute the controller instructions and consume the electrical energy generated by the battery stack. The control components are auxiliary functional components of the electronic control unit.

2. The hydrogen circulation structure of a fuel cell system according to claim 1, characterized in that: A first pressure sensor is installed on the anode inlet main pipe; a second pressure sensor and a second temperature sensor are installed on the anode outlet main pipe; a fourth temperature sensor is installed on the pipe connecting the radiator and the inlet of the battery stack unit; and a fifth temperature sensor is installed on the pipe between the battery stack outlet and the junction of the first branch and the second branch.

3. The hydrogen circulation structure of a fuel cell system according to claim 2, characterized in that: The first pressure sensor is used to detect the pressure of the gas entering the anode as the first pressure value; the second pressure sensor is used to detect the pressure of the gas exiting the anode as the second pressure value; the second temperature sensor is used to detect the temperature of the gas exiting the anode as the second temperature value; and the fourth temperature sensor is used to detect the temperature of the coolant entering the battery stack as the fourth temperature value. The fifth temperature sensor is used to detect the temperature of the coolant exiting the battery stack as the fifth temperature value.

4. The hydrogen circulation structure of a fuel cell system according to claim 1, characterized in that: The battery stack unit includes a battery stack, a cathode inlet pipe, a cathode outlet, a cathode outlet, a cathode outlet pipe, a coolant inlet, a coolant outlet, an anode inlet, an anode outlet, a load line, and a voltage acquisition line. The cathode reaction gas from the cathode inlet pipe enters the battery stack through the cathode outlet, and the anode reaction gas from the anode inlet pipe enters the battery stack through the anode outlet. The battery stack coolant from the cooling circulation unit enters the battery stack through the coolant inlet. The coolant outlet is used to remove the battery stack coolant, the cathode outlet is used to discharge the remaining cathode reaction gas, and the anode outlet is used to discharge the remaining anode reaction gas.

5. The hydrogen circulation structure of a fuel cell system according to claim 3, characterized in that: The first pressure value, the second temperature value, and the second pressure value are system operation status monitoring values, while the first temperature value, the third temperature value, the fourth temperature value, the fifth temperature value, and the first relative humidity value are control target variables.

6. The hydrogen circulation structure of a fuel cell system according to claim 3, characterized in that: A hydrogen pressure stabilizing device is installed on the gas source branch, and the hydrogen pressure stabilizing device is controlled in a closed loop with the first pressure value.

7. The hydrogen circulation structure of a fuel cell system according to claim 3, characterized in that: An exhaust device is installed on the exhaust branch, and the exhaust device is intermittently activated to perform exhaust actions according to the exhaust and drainage needs of the battery stack.

8. The hydrogen circulation structure of a fuel cell system according to claim 1, characterized in that: The circulating cooler can be either air-cooled or liquid-cooled.

9. A method for controlling temperature and humidity parameters in the hydrogen circulation structure of a fuel cell system according to any one of claims 1-8, characterized in that, include: Collect the operating current and voltage values ​​of the battery stack, and collect the temperature, pressure, and relative humidity values ​​of the cooling circulation unit and the hydrogen circulation management unit; The hydrogen circulation pump speed, temperature setpoint, relative humidity setpoint, target value, and minimum threshold for detection values ​​are determined based on the battery stack's operating current and voltage. Temperature parameter control process: When the difference between the temperature setpoint and the first temperature value is greater than the minimum threshold, the first temperature control unit TC1 obtains its output value through PI or PID control based on the comparison result between the temperature setpoint and the first temperature value and the minimum threshold; otherwise, it returns to the beginning of the program. Next, it checks whether the difference between the output value of the first temperature control unit TC1 and the third temperature value is greater than the minimum threshold. If the result is yes, the third temperature control unit TC3 obtains its output value through PI or PID control based on the comparison result between the temperature setpoint and the first temperature value and the minimum threshold. The heater power is adjusted according to the instructions of the third temperature control unit TC3. If the result is no, the program returns to the beginning. Then, it checks whether the difference between the output value of the first temperature control unit TC1 and the third temperature value is less than or equal to the minimum threshold. If the result is yes, it checks whether the difference between the temperature setpoint and the first temperature value is less than or equal to the minimum threshold. If the result is yes, the heater maintains its state; if the result is no, the program returns to the beginning. Humidity parameter control process: When the difference between the relative humidity setpoint and the first relative humidity value is greater than the minimum threshold, the first relative humidity control unit HC1 obtains the controller output value through PI or PID control law based on the comparison result between the difference between the relative humidity setpoint and the first relative humidity value and the minimum threshold. The cooling medium flow rate of the circulating cooler is adjusted according to the instruction of the first relative humidity control unit HC1. It continues to judge whether the difference between the relative humidity setpoint and the first relative humidity value is less than or equal to the minimum threshold. If the result is yes, the cooler maintains its state; if the result is no, it returns to the program start step.

Images