Fuel cell stack durability accelerated test method and durability accelerated test device

Abstract

The present invention belongs to the field of fuel cell detection technology, and discloses a fuel cell stack durability accelerated test method and durability accelerated test device, in order to solve the problem that the existing test method cannot realize the function of rapidly increasing or decreasing the temperature of the stack during the accelerated working condition test, and cannot consider the impact of the rapid change of the working temperature of the stack on the durability; a multi-nozzle hydrogen injector is used to control the anode reaction gas supply, and an air flow controller is used in combination with a control strategy to control the cathode reaction gas supply; and a temperature control system is used to adjust and control the fuel cell stack working temperature and the reaction gas supply temperature under accelerated aging conditions in real time. The durability accelerated test results of the fuel cell stack are obtained through the above control process. The present invention realizes the function of rapidly adjusting the reaction gas supply and the stack working temperature under accelerated aging conditions, so that the fuel cell stack durability accelerated test system can be used for accelerated aging tests to obtain accurate test results.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cell detection, and in particular relates to a fuel cell stack durability accelerated testing method and a durability accelerated testing device. Background Art

[0002] At present, fuel cells have the advantages of no pollution, high energy conversion efficiency, fast start-up speed, low vibration during operation, and lower operating temperature than internal combustion engines. However, fuel cells also have difficulties that limit their commercial application. One of the most critical issues is the life of the fuel cell, that is, durability. Through various durability tests on fuel cell stacks, we can have a good understanding of the life of the fuel cell stack and the mechanism of durability attenuation, and contribute to increasing the life of the fuel cell stack. The durability test of the fuel cell stack is extremely time-consuming, usually requiring thousands of hours of measurement, and also consuming manpower and material resources, which brings great limitations to the durability test of the fuel cell stack.

[0003] There are two load conditions in the durability test of fuel cell stacks: steady state and dynamic. Fuel cell stacks will experience various attenuations during long-term operation under dynamic load conditions. The durability test of dynamic loads that simulate the actual operating conditions of vehicles can better reflect the actual situation. Different dynamic conditions will cause different attenuation rates. If the attenuation rate is made faster and the same attenuation effect is achieved in a shorter time under the condition of changing the dynamic conditions, this is undoubtedly of great significance for durability research. The existing patent CN111082093A provides a hydrogen fuel cell durability test system and working method, which can test the durability of fuel cells. However, the load change frequency of the durability accelerated test is faster and the change range is larger. The working conditions of the stack will also change rapidly, such as gas flow, working temperature, and working pressure, so the test system needs to be improved. The prior art does not mention the aspect of accelerated durability testing. In order to shorten the time of durability testing, it is necessary to design a fuel cell stack durability accelerated test system and its working method.

[0004] Through the above analysis, the problems and defects of the prior art are as follows:

[0005] (1) The durability test of fuel cell stacks is extremely time-consuming, usually requiring thousands of hours of measurement, and is labor-intensive and material-intensive, which greatly limits the durability test of fuel cell stacks. When the existing fuel cell stack test system and device are used for accelerated stack testing, there are problems with delayed and untimely supply of reaction gas, and a long time is required for temperature control and adjustment when the stack temperature needs to change significantly. The existence of these problems leads to inaccurate results of accelerated stack durability tests.

[0006] (2) The existing fuel cell stack test system and method are mainly aimed at steady-state performance testing. When used for constant-current fuel cell stack durability testing, the working parameters such as reaction gas flow, operating temperature, working pressure, and intake air humidity are stable and can be well controlled. When used for dynamic condition durability testing, the above working parameters will undergo transient changes, affecting the fuel cell stack performance and further affecting the fuel cell stack durability test results. Under the condition of accelerated condition durability testing of the fuel cell stack, the existing test system and method cannot meet the test requirements for rapid response of the working parameters, and the durability test results cannot fully reflect the impact of the accelerated condition on the durability of the fuel cell stack. In particular, the existing test system and method cannot realize the function of rapidly increasing or decreasing the temperature of the fuel cell stack during accelerated condition testing, and cannot consider the impact of rapid changes in the fuel cell stack operating temperature on durability, which is a function that future research on accelerated durability testing of the fuel cell stack needs to have.

[0007] The significance of solving the above problems and defects is:

[0008] According to the requirements of fuel cell stack accelerated testing for reaction gas control and rapid temperature regulation, the present invention designs a stack durability accelerated testing system and device, proposes a corresponding testing method, and provides a solution for the stack durability accelerated testing, thereby eliminating the influence of reaction gas supply delay and slow temperature regulation on inaccurate stack durability test results. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a fuel cell stack durability accelerated testing method and durability accelerated testing device.

[0010] The present invention is implemented as follows: a fuel cell stack durability accelerated testing method, comprising:

[0011] A multi-nozzle hydrogen injector is used to control the anode reaction gas supply, and an air flow controller is used in combination with a control strategy to control the cathode reaction gas supply;

[0012] And using the temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time;

[0013] The durability accelerated test result of the fuel cell stack is accurately obtained through the above control process.

[0014] Further, the use of a multi-nozzle hydrogen injector to control the anode reaction gas supply includes:

[0015] Step 1, nitrogen purge is performed, the first three-way valve and the second three-way valve close the hydrogen air channel, and the fuel cell is officially operated after the nitrogen purge is completed;

[0016] Step 2, air is provided by a high-pressure air source, passes through a first three-way valve, a first pressure reducing valve, a first filter, an air flow controller, a first humidifier to the inside of the fuel cell stack, and finally exhausts the exhaust gas through a first back pressure valve;

[0017] In step 3, hydrogen is provided by a high-pressure hydrogen source, and the hydrogen passes through a second three-way valve, a second pressure reducing valve, a second filter, a multi-nozzle hydrogen injector, and a second humidifier to the interior of the fuel cell stack. The exhaust gas generated at the anode of the fuel cell stack is recovered by a hydrogen recovery system and finally enters the hydrogen branch.

[0018] Further, the method of controlling the cathode reaction gas supply by using an air flow controller in combination with a control strategy includes:

[0019] In the first step, when the fuel cell is officially running, the initial cathode reaction gas supply is set to be much larger than the actual demand, and the air flow controller is controlled to supply air according to the set initial cathode reaction gas supply;

[0020] In the second step, the data acquisition module and the control module monitor and analyze the changes in the electronic load operating conditions, and send control signals to the multi-nozzle hydrogen injector and the air flow controller to ensure that the gas supply meets the actual gas supply requirements.

[0021] Furthermore, the required theoretical gas supply is determined by the current density required by the electronic load, and the required actual gas supply is obtained by multiplying the theoretical gas supply by the excess coefficient;

[0022] The air flow controller adopts an excess coefficient of not less than 2.5 on the cathode side. When the operating current density changes from low to high, a feedforward adjustment method is adopted to change the gas flow 10 seconds in advance.

[0023] Furthermore, the use of a temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time includes:

[0024] (1) The coolant is driven by an electronically controlled circulation pump into the coolant channel inside the fuel cell stack. The coolant is provided by the first coolant storage tank. At this time, the second valve is closed;

[0025] (2) When the coolant needs to be heated so that the temperature of the fuel cell stack quickly reaches the working requirement, the heater heats the coolant and then delivers it to the fuel cell coolant flow channel. At this time, the third valve is closed, and the coolant directly enters the fuel cell stack through the third bypass pipe without passing through the radiator, and the electronic fan is turned off;

[0026] (3) When the coolant does not need to be heated, the heater does not work, the third valve is opened, the coolant passes through the radiator, and the electronic fan is turned on;

[0027] (4) When cooling the battery stack, close the first valve and the first electronic fan, and open the second valve and the second electronic fan. At this time, the coolant temperature of the second temperature control subsystem is the same as the room temperature, and cooling is performed.

[0028] In the present invention, when hydrogen leakage or abnormal voltage fluctuation occurs in the fuel cell stack, the system determines that the fuel cell stack is in a dangerous situation, and the alarm device sounds an alarm. At the same time, the system cuts off the supply of hydrogen and air, opens the nitrogen channel to purge the fuel cell stack to protect the fuel cell stack;

[0029] In the present invention, the electrochemical workstation measures and characterizes the aging of the fuel cell stack;

[0030] In the present invention, the supply of hydrogen and air is cut off after all cycles are completed, and the system enters a shutdown state after nitrogen purge is completed.

[0031] Another object of the present invention is to provide a fuel cell stack durability accelerated test device, which is provided with a high-pressure air source, a nitrogen source and a high-pressure hydrogen source connected to the fuel cell stack through pipelines, as well as an electronic load and an electrochemical workstation;

[0032] The pipeline between the high-pressure air source and the fuel cell stack is sequentially connected with a first three-way valve, a first pressure reducing valve, a first pressure sensor, a first filter, an air flow controller, a first flow sensor, a first bypass valve, a first humidifier, a first temperature sensor and a first humidity sensor;

[0033] The pipeline between the high-pressure hydrogen source and the fuel cell stack is sequentially connected with a second three-way valve, a second pressure reducing valve, a second pressure sensor, a second filter, a multi-nozzle hydrogen injector, a second flow sensor, a second bypass valve, a second humidifier, a second temperature sensor and a second humidity sensor, and the fuel cell stack is connected to the second three-way valve through a hydrogen recovery system;

[0034] The first three-way valve is connected to the second three-way valve via a pipeline, and the nitrogen source is connected to the first three-way valve and the second three-way valve via a connecting pipeline.

[0035] The fuel cell stack is connected to the first radiator and the second radiator through pipelines. The output end of the first radiator is connected to the fuel cell stack through the first coolant storage tank, the first valve, the heater, the third temperature sensor, and the electronically controlled circulating water pump in sequence. The output end of the second radiator is connected to the fuel cell stack through the second coolant storage tank, the second valve, the first valve, the heater, the third temperature sensor, and the electronically controlled circulating water pump in sequence.

[0036] Furthermore, a first bypass pipe is connected between the first bypass valve and the first temperature sensor, a second bypass pipe is connected between the second bypass valve and the second temperature sensor, and a third bypass pipe is connected between the second valve and the heater.

[0037] Furthermore, the first radiator and the second radiator are connected to a first electronic fan and a second electronic fan respectively.

[0038] Furthermore, the high-pressure air source, the nitrogen source and the high-pressure hydrogen source are respectively connected to a first manual safety valve, a second manual safety valve and a third manual safety valve through pipelines.

[0039] Furthermore, a data acquisition and control system is provided, which is connected to each detector group and electronic load, electrochemical workstation, and alarm device through connecting lines, and the alarm device is connected to the fuel cell stack.

[0040] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0041] (1) The existing fuel cell test system gas supply device generally uses a pressure regulating valve for direct supply, and does not use an injector. Different from the mechanical opening adjustment of the traditional pressure regulating valve, the injector is a component based on the principle of time control. By changing the timing, duty cycle, frequency, and quantity of the solenoid valve opening, the hydrogen intake volume can be adjusted as desired, and has excellent response characteristics.

[0042] (2) Based on the injector, a multi-nozzle injector is selected. When the anode flow demand is small, only one valve is opened and a small duty cycle is given. As the flow increases, the duty cycle gradually increases until it is fully open. If a larger flow is required, multiple valves are opened in sequence. The air intake volume during the accelerated aging test is larger than that of the general aging test. The multi-nozzle hydrogen injector not only solves the problem of the dynamic follow-up of the anode gas, but also solves the problem of gas supply when the flow changes greatly, making the dynamic response faster and more accurate.

[0043] (3) Since the flow rate on the cathode side is much larger than that on the anode side, the injector is not applicable here, so other methods are used on the cathode side, such as the cathode reaction gas excess coefficient is not less than 2.5, so that the actual gas supplied is much more than the theoretical gas consumption, which alleviates the problem of gas response lag to a certain extent and avoids the test system supplying insufficient reaction gas to affect the durability test results of the stack. If it is necessary to examine the effect of the reaction gas supply on the durability of the stack, the cathode excess coefficient can be adjusted.

[0044] (4) The cathode side air flow controller adopts a feedforward adjustment method. When the current density changes from low to high, feedforward adjustment is performed through the PID controller to output the flow value 10 seconds in advance. Since the operating conditions of the fuel cell stack are known, the feedforward adjustment method can effectively solve the problem of gas shortage caused by the delayed response of the cathode gas.

[0045] (5) Using high-precision and high-sensitivity flow sensors to monitor the flow of reactant gases can determine whether the reactant gas supply can meet the requirements of the fuel cell stack accelerated test.

[0046] (6) The present invention adds a heating device to the temperature control system to enable it to have a coolant heating function. When the fuel cell stack is just started, it takes a long time (especially in winter) for the fuel cell stack to reach the operating temperature by its own heat generation, which will affect the durability test results of the stack; when the fuel cell needs to be raised from a certain operating temperature to a higher temperature according to the durability test requirements, quickly heating the coolant can also reduce the impact of the temperature rise stage on the durability test results.

[0047] (7) The temperature control system using two sets of temperature control subsystems has a rapid cooling function. Temperature will also affect the durability of the fuel cell stack. When the stack needs to be operated from high temperature to low temperature, the first temperature control subsystem can be turned off and the second temperature control subsystem can be started to achieve a rapid cooling function.

[0048] (8) The temperature control system uses air cooling to cool the coolant. The coolant is cooled by an electronic fan when passing through the radiator. The radiator and the coolant storage tank are located at the same horizontal plane and at the same height. When the electronic fan dissipates heat from the coolant in the radiator, it can also dissipate heat from the coolant storage tank.

[0049] (9) The electronic fan and the electronically controlled circulating water pump of the temperature control system adopt the synchronous control principle when working to achieve the effect of rapid cooling.

[0050] (10) When the coolant needs to be heated, the third valve 43 controls the coolant to flow directly to the water tank without passing through the radiator, thus saving heating time.

[0051] (11) The alarm device can detect voltage fluctuations and hydrogen leaks, and alarm when voltage fluctuations exceeding normal conditions or hydrogen leaks are detected. At the same time, the nitrogen supply system can not only purge at the end of each cycle, but also purge the fuel cell stack when the alarm device sounds an alarm, thereby protecting the fuel cell stack while ensuring personal safety.

[0052] Comparative technical or experimental results.

[0053] Existing stack testing technology is mainly aimed at steady-state performance testing. When the dynamic operating conditions do not change dramatically, the response speed of the reaction gas supply and the stack operating temperature regulation can basically meet the requirements of the stack durability test. However, during the accelerated test of the stack durability, due to the dramatic dynamic changes in the test conditions and the frequency, the response speed of the reaction gas supply and the stack operating temperature regulation is difficult to keep up, resulting in the stack being short of gas, the temperature being too high or too low, and the durability test results under accelerated aging conditions being inaccurate. The present invention adopts a method of controlling the anode reaction gas supply with a multi-nozzle hydrogen injector, controlling the cathode reaction gas supply with an air flow controller combined with a control strategy design, and adjusting the operating temperature with a temperature control system of two sets of temperature control subsystems, so as to realize the function of rapid regulation of the reaction gas supply and the stack operating temperature under accelerated aging conditions, so that the fuel cell stack durability accelerated test system proposed by the present invention can be used for accelerated aging tests and obtain accurate test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 It is a schematic structural diagram of a fuel cell stack durability acceleration test device provided by an embodiment of the present invention;

[0056] In the figure: 1, high-pressure air source; 2, first three-way valve; 3, first pressure reducing valve; 4, first pressure sensor; 5, first filter; 6, air flow controller; 7, first flow sensor; 8, first bypass valve; 9, first bypass pipeline; 10, first humidifier; 11, first temperature sensor; 12, first humidity sensor; 13, first back pressure valve; 14, first manual safety valve; 15, nitrogen source; 16, second manual safety valve; 17, high-pressure hydrogen source; 18, second three-way valve; 19, second pressure reducing valve; 20, second pressure sensor; 21, second filter; 22, multi-nozzle hydrogen injector; 23, second flow sensor; 24, second bypass valve; 25, second bypass pipeline; 26. Second humidifier; 27. Second temperature sensor; 28. Second humidity sensor; 29. ​​Second back pressure valve; 30. Third manual safety valve; 31. Fuel cell stack; 32. Electronic load; 33. Electrochemical workstation; 34. Alarm device; 35. Data acquisition and control system; 36. Electronically controlled circulating water pump; 37. Third temperature sensor; 38. Heater; 39. First valve; 40. First coolant storage tank; 41. First radiator; 42. First electronic fan; 43. Third valve; 44. Third bypass pipe; 45. Second valve; 46. Second coolant storage tank; 47. Second radiator; 48. Second electronic fan; 49. Fourth temperature sensor; 50. Hydrogen recovery system.

[0057] Figure 2 It is a schematic diagram of a reference operating condition provided by an embodiment of the present invention.

[0058] Figure 3 It is a schematic diagram of the accelerated aging condition provided by an embodiment of the present invention.

[0059] Figure 4 It is a flow chart of a control system provided by an embodiment of the present invention.

[0060] Figure 5 It is a flow chart of a temperature control system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0062] In view of the problems existing in the prior art, the present invention provides a fuel cell stack durability accelerated testing method and durability accelerated testing device, and the present invention is described in detail below in conjunction with the accompanying drawings.

[0063] The present invention provides a fuel cell stack durability accelerated test method, comprising: using a multi-nozzle hydrogen injector to control the anode reaction gas supply, and using an air flow controller in combination with a control strategy to control the cathode reaction gas supply;

[0064] And using the temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time;

[0065] The durability accelerated test result of the fuel cell stack is accurately obtained through the above control process.

[0066] Preferably, the controlling the supply of anode reaction gas by using a multi-nozzle hydrogen injector comprises:

[0067] Step 1, nitrogen purge is performed, the first three-way valve and the second three-way valve close the hydrogen air channel, and the fuel cell is officially operated after the nitrogen purge is completed;

[0068] Step 2, air is provided by a high-pressure air source, passes through a first three-way valve, a first pressure reducing valve, a first filter, an air flow controller, a first humidifier to the inside of the fuel cell stack, and finally exhausts the exhaust gas through a first back pressure valve;

[0069] In step 3, hydrogen is provided by a high-pressure hydrogen source, and the hydrogen passes through a second three-way valve, a second pressure reducing valve, a second filter, a multi-nozzle hydrogen injector, and a second humidifier to the interior of the fuel cell stack. The exhaust gas generated at the anode of the fuel cell stack is recovered by a hydrogen recovery system and finally enters the hydrogen branch.

[0070] The method of controlling the cathode reaction gas supply by using an air flow controller in combination with a control strategy includes:

[0071] In the first step, when the fuel cell is officially running, the initial cathode reaction gas supply is set to be much larger than the actual demand, and the air flow controller is controlled to supply air according to the set initial cathode reaction gas supply;

[0072] In the second step, the data acquisition module and the control module monitor and analyze the changes in the electronic load operating conditions, and send control signals to the multi-nozzle hydrogen injector and the air flow controller to ensure that the gas supply meets the actual gas supply requirements.

[0073] The required theoretical gas supply is determined by the current density required by the electronic load, and the actual gas supply required is obtained by multiplying the theoretical gas supply by the excess coefficient.

[0074] The air flow controller adopts an excess coefficient of not less than 2.5 on the cathode side. When the operating current density changes from low to high, a feedforward adjustment method is adopted to change the gas flow 10 seconds in advance.

[0075] The method of using the temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time includes:

[0076] (1) The coolant is driven by an electronically controlled circulation pump into the coolant channel inside the fuel cell stack. The coolant is provided by the first coolant storage tank. At this time, the second valve is closed;

[0077] (2) When the coolant needs to be heated so that the temperature of the fuel cell stack quickly reaches the working requirement, the heater heats the coolant and then delivers it to the fuel cell coolant flow channel. At this time, the third valve is closed, and the coolant directly enters the fuel cell stack through the third bypass pipe without passing through the radiator, and the electronic fan is turned off;

[0078] (3) When the coolant does not need to be heated, the heater does not work, the third valve is opened, the coolant passes through the radiator, and the electronic fan is turned on;

[0079] (4) When cooling the battery stack, close the first valve and the first electronic fan, and open the second valve and the second electronic fan. At this time, the coolant temperature of the second temperature control subsystem is the same as the room temperature, and cooling is performed.

[0080] The specific steps may include:

[0081] Step 1: nitrogen purge, the first three-way valve and the second three-way valve close the hydrogen air channel, and the fuel cell is officially operated after the nitrogen purge is completed;

[0082] Step 2: air is provided by a high-pressure air source, passes through a first three-way valve, a first pressure reducing valve, a first filter, an air flow controller, a first humidifier to the inside of the fuel cell stack, and finally exhausts the exhaust gas through a first back pressure valve;

[0083] Step 3: Hydrogen is provided by a high-pressure hydrogen source, and the hydrogen passes through a second three-way valve, a second pressure reducing valve, a second filter, a multi-nozzle hydrogen injector, and a second humidifier to the inside of the fuel cell stack. The tail gas generated at the anode of the fuel cell stack is recovered by a hydrogen recovery system and finally enters the hydrogen branch.

[0084] Step 4: At the end of the cycle, whether to purge with nitrogen is selected. If nitrogen purge is selected, nitrogen is provided by a nitrogen source and enters the anode and cathode through the first three-way valve and the second three-way valve. At this time, the three-way valve closes the hydrogen and air inlets and opens the nitrogen inlet. After passing through the air flow controller, the bypass valve is opened and enters the fuel cell stack through the bypass pipe. The cathode nitrogen tail gas is discharged from the first back pressure valve, and the anode nitrogen tail gas is discharged from the second back pressure valve. The hydrogen recovery system is closed;

[0085] Step 5: The data acquisition module and the control module monitor and analyze the changes in the working conditions of the electronic load, and send control signals to the multi-nozzle hydrogen injector and the air flow controller to ensure that the gas supply reaches the actual gas supply required;

[0086] Step 6: When the fuel cell stack leaks hydrogen or experiences abnormal voltage fluctuations, the system determines that the fuel cell stack is in a dangerous situation, and the alarm device sounds an alarm. At the same time, the system cuts off the supply of hydrogen and air, and opens the nitrogen channel to purge the fuel cell stack to protect the fuel cell stack.

[0087] Step 7: The electrochemical workstation measures and characterizes the aging of the fuel cell stack;

[0088] Step 8: After all cycles are completed, the hydrogen and air supply are cut off, and the system enters the shutdown state after the nitrogen purge is completed.

[0089] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0090] Example

[0091] like Figure 1 As shown, the fuel cell stack durability accelerated test device provided by the embodiment of the present invention is provided with a high-pressure air source 1, a nitrogen source 15 and a high-pressure hydrogen source 17 connected to the fuel cell stack 31 through pipelines, as well as an electronic load 32 and an electrochemical workstation 33;

[0092] The pipeline between the high-pressure air source 1 and the fuel cell stack 31 is sequentially connected with a first three-way valve 2, a first pressure reducing valve 3, a first pressure sensor 4, a first filter 5, an air flow controller 6, a first flow sensor 7, a first bypass valve 8, a first humidifier 10, a first temperature sensor 11 and a first humidity sensor 12;

[0093] The pipeline between the high-pressure hydrogen source 17 and the fuel cell stack 31 is sequentially connected with a second three-way valve 18, a second pressure reducing valve 19, a second pressure sensor 20, a second filter 21, a multi-nozzle hydrogen injector 22, a second flow sensor 23, a second bypass valve 24, a second humidifier 26, a second temperature sensor 27 and a second humidity sensor 28, and the fuel cell stack is connected to the second three-way valve through a hydrogen recovery system;

[0094] The first three-way valve 2 is connected to the second three-way valve 18 through a pipeline, and the nitrogen source 15 is connected to the first three-way valve 2 and the second three-way valve 18 through a connecting pipeline.

[0095] The fuel cell stack 31 is connected to the first radiator 41 and the second radiator 47 through pipelines. The output end of the first radiator 41 is connected to the fuel cell stack 31 through the first coolant storage tank 40, the first valve 39, the heater 38, the third temperature sensor 37, and the electronically controlled circulating water pump 36 in sequence. The output end of the second radiator 47 is connected to the fuel cell stack 31 through the second coolant storage tank 46, the second valve 45, the first valve 39, the heater 38, the third temperature sensor 37, and the electronically controlled circulating water pump 36 in sequence.

[0096] A first bypass pipe 9 is connected between the first bypass valve 8 and the first temperature sensor 11 , a second bypass pipe 25 is connected between the second bypass valve 24 and the second temperature sensor 27 , and a third bypass pipe is connected between the second valve and the heater.

[0097] The first heat sink 41 and the second heat sink 47 are connected to a first electronic fan 42 and a second electronic fan 48 , respectively.

[0098] The high-pressure air source 1, the nitrogen source 15 and the high-pressure hydrogen source 17 are respectively connected to a first manual safety valve, a second manual safety valve and a third manual safety valve through pipelines.

[0099] The data acquisition and control system 35 is connected to each detector group and electronic load, electrochemical workstation, and alarm device through connecting lines, and the alarm device 34 is connected to the fuel cell stack.

[0100] The first detector group includes a first pressure reducing valve 3 , a first pressure sensor 4 , an air flow controller, a first flow sensor 7 , a first humidifier 10 , a first temperature sensor 11 , and a first humidity sensor 12 .

[0101] The second detector group includes a second pressure reducing valve 19 , a second pressure sensor 20 , a multi-nozzle hydrogen injector 22 , a second flow sensor 23 , a second humidifier 26 , a second temperature sensor 27 , and a second humidity sensor 28 .

[0102] The third detector group includes a third temperature sensor 37 and a fourth temperature sensor 49. The fourth detector group is an alarm device. The temperature control system includes an electrically controlled circulating water pump 36, a heater 38, a third temperature sensor 37, a first valve 39, a first coolant storage tank 40, a first radiator 41, a first electronic fan 42, a second valve 45, a second coolant storage tank 46, a second radiator 47, a second electronic fan 48, a third valve 43, a third bypass pipe 44, and a fourth temperature sensor 49.

[0103] The first radiator 41, the first electronic fan 42, the first coolant storage tank 40, the third valve 43, and the third bypass pipe 44 are the first temperature control subsystem; the second radiator 47, the second electronic fan 48, and the second coolant storage tank 46 are the second temperature control subsystem.

[0104] Fuel cell stack durability testing is time-consuming, labor-intensive, and has high test costs. If existing tests are to be more in line with actual conditions, the cycle conditions used by the electronic load are generally extracted based on the actual operating data of fuel cell vehicles (hereinafter referred to as the benchmark cycle conditions). In order to reduce the duration of the durability test, accelerate the attenuation rate of the fuel cell, and reduce the test cost, accelerated aging test conditions can be used during the test. Accelerated aging test conditions can be designed according to the aging mechanism and calculated and analyzed through an aging simulator, and finally the accelerated aging test conditions with the corresponding acceleration multiples are obtained, which saves time and achieves the same aging effect.

[0105] When the fuel cell is running, nitrogen purge is first performed. At this time, the first three-way valve 2 and the second three-way valve 18 close the hydrogen air channel. After the nitrogen purge is completed, the fuel cell is officially operated. Air is provided by a high-pressure air source, first passes through the first three-way valve 2, the first pressure reducing valve 3, the first filter 5, the air flow controller, the first humidifier 10 to the inside of the fuel cell stack, and finally discharges the tail gas through the first back pressure valve 13. At the same time, hydrogen is provided by a high-pressure hydrogen source, and hydrogen passes through the second three-way valve 18, the second pressure reducing valve 19, the second filter 21, the multi-nozzle hydrogen injector 22, and the second humidifier 26 to the inside of the fuel cell stack 31. The tail gas generated at the anode of the fuel cell stack 31 is recovered by the hydrogen recovery system and finally enters the hydrogen branch. At the end of a cycle, it is possible to choose whether to purge with nitrogen. If nitrogen purge is selected, nitrogen is provided by a nitrogen source and enters the anode and cathode through the first three-way valve 2 and the second three-way valve 18. At this time, the three-way valve closes the hydrogen and air inlets and opens the nitrogen inlet. After passing through the air flow controller, the bypass valve is opened and enters the fuel cell stack through the bypass pipe. The cathode nitrogen tail gas is discharged by the first back pressure valve 13, and the anode nitrogen tail gas is discharged by the second back pressure valve 29. At this time, the hydrogen recovery system is closed. The high-pressure air source, nitrogen source, and high-pressure hydrogen source all have manual safety valves.

[0106] When the fuel cell stack is running, the frequency and amplitude of the accelerated aging test conditions change rapidly, so the gas supply system and temperature control system need to be dynamically regulated with better followability. In terms of the gas supply system: the data acquisition and control system monitors and analyzes the changes in the electronic load working conditions. The theoretical gas supply required at this time can be determined by the current density required by the electronic load. The theoretical gas supply multiplied by the excess coefficient is the actual gas supply required. At this time, the control signal is sent to the multi-nozzle hydrogen injector and the air flow controller to make the gas supply meet the requirements; the gas supply changes with the current density required by the electronic load. The multi-nozzle hydrogen injector on the anode side can achieve a good dynamic response effect. In order to avoid the occurrence of gas shortage due to rapid changes in working conditions on the cathode side, the following improvements are made: 1) In the existing experiments, the excess coefficient generally used on the cathode side is 1.5-2.5. In order to alleviate the gas shortage, an excess coefficient of not less than 2.5 is used; 2) When the working current density changes from low to high, the feedforward adjustment method is used to change the gas flow 10s in advance. In terms of the temperature control system: the coolant is driven by the electronically controlled circulating pump to enter the coolant channel inside the fuel cell stack, and the coolant is provided by the first coolant storage tank 40, and the second valve 45 is closed. When the coolant needs to be heated so that the temperature of the stack quickly reaches the working requirements, the heater heats the coolant and then delivers it to the fuel cell coolant flow channel. At this time, the third valve 43 is closed, and the coolant enters the stack directly through the third bypass pipe 44 without passing through the radiator, and the electronic fan is turned off. When the coolant does not need to be heated, the heater does not work. At this time, the third valve 43 is opened, the coolant passes through the radiator, and the electronic fan is turned on. The temperature measured by the fourth temperature sensor 49 defaults to the operating temperature of the fuel cell stack, and the temperature measured by the third temperature sensor 37 is the temperature of the coolant entering the fuel cell stack 31. The accelerated aging experiment also needs to take into account the impact of temperature on the durability of the stack. When the stack needs to be cooled, the first valve 39 and the first electronic fan 42 are closed, and the second valve 45 and the second electronic fan 48 are opened. At this time, the coolant temperature of the second temperature control subsystem is roughly the same as the room temperature, which can achieve a rapid cooling effect.

[0107] When a fuel cell stack leaks hydrogen or experiences abnormal voltage fluctuations, the system determines that the fuel cell stack is in a dangerous situation and the alarm device sounds an alarm. At the same time, the system cuts off the supply of hydrogen and air and opens the nitrogen channel to purge the fuel cell stack to protect the fuel cell stack.

[0108] The electrochemical workstation can be used to measure and characterize the aging of fuel cell stacks.

[0109] After all cycles are completed, the hydrogen and air supply is cut off, and the system enters the shutdown state after the nitrogen purge is completed. The flow chart of the entire control system is as follows Figure 4 The flow chart of the temperature control system is shown in Figure 5 shown.

[0110] In an embodiment of the present invention, the gas supply of the test system changes with the electronic load. In order to alleviate the problem of delayed dynamic response of the gas supply, a multi-nozzle hydrogen injector is used to supply hydrogen. At the same time, since the cathode gas flow is relatively large, it is not suitable to use an injector, so an excess coefficient ≥ 2.5 and a feedforward adjustment method are used to supply gas; the temperature control system can not only realize the heating function but also the rapid cooling function.

[0111] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0112] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A fuel cell stack durability accelerated testing method, characterized in that: The fuel cell stack durability accelerated testing method comprises: A multi-nozzle hydrogen injector is used to control the anode reaction gas supply, and an air flow controller is used in combination with a control strategy to control the cathode reaction gas supply; And using the temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time; Accurately obtain the durability accelerated test result of the fuel cell stack through the above control process; The use of a multi-nozzle hydrogen injector to control the anode reaction gas supply includes: Step 1, nitrogen purge is performed, the first three-way valve and the second three-way valve close the hydrogen air channel, and the fuel cell is officially operated after the nitrogen purge is completed; Step 2, air is provided by a high-pressure air source, passes through a first three-way valve, a first pressure reducing valve, a first filter, an air flow controller, a first humidifier to the inside of the fuel cell stack, and finally exhausts the exhaust gas through a first back pressure valve; Step 3, hydrogen is provided by a high-pressure hydrogen source, and the hydrogen passes through a second three-way valve, a second pressure reducing valve, a second filter, a multi-nozzle hydrogen injector, and a second humidifier to the inside of the fuel cell stack. The tail gas generated at the anode of the fuel cell stack is recovered by a hydrogen recovery system and finally enters the hydrogen branch; The method of controlling cathode reaction gas supply by using an air flow controller in combination with a control strategy includes: In the first step, when the fuel cell is officially running, the initial cathode reaction gas supply is set to be much larger than the actual demand, and the air flow controller is controlled to supply air according to the set initial cathode reaction gas supply; In the second step, the data acquisition module and the control module monitor and analyze the changes in the electronic load operating conditions, and send control signals to the multi-nozzle hydrogen injector and the air flow controller to ensure that the gas supply meets the actual gas supply requirements.

2. The fuel cell stack durability accelerated testing method according to claim 1, characterized in that: The required theoretical gas supply is determined by the current density required by the electronic load, and the actual gas supply required is obtained by multiplying the theoretical gas supply by the excess coefficient. The air flow controller adopts an excess coefficient of not less than 2.5 on the cathode side. When the operating current density changes from low to high, a feedforward adjustment method is adopted to change the gas flow 10 seconds in advance.

3. The fuel cell stack durability accelerated testing method according to claim 1, characterized in that: The method of using the temperature control system to adjust and control the fuel cell stack operating temperature and the reaction gas supply temperature under accelerated aging conditions in real time includes: (1) The coolant is driven by an electronically controlled circulation pump into the coolant channel inside the fuel cell stack. The coolant is provided by the first coolant storage tank. At this time, the second valve is closed; (2) When the coolant needs to be heated so that the temperature of the fuel cell stack quickly reaches the working requirement, the heater heats the coolant and then delivers it to the fuel cell coolant flow channel. At this time, the third valve is closed, and the coolant directly enters the fuel cell stack through the third bypass pipe without passing through the radiator, and the electronic fan is turned off; (3) When the coolant does not need to be heated, the heater does not work, the third valve is opened, the coolant passes through the radiator, and the electronic fan is turned on; (4) When cooling the battery stack, close the first valve and the first electronic fan, and open the second valve and the second electronic fan. At this time, the coolant temperature of the second temperature control subsystem is the same as the room temperature, and cooling is performed.

4. A fuel cell stack durability accelerated testing device, characterized in that: The fuel cell stack durability accelerated test device is provided with a high-pressure air source, a nitrogen source and a high-pressure hydrogen source connected to the fuel cell stack through pipelines, as well as an electronic load and an electrochemical workstation; The pipeline between the high-pressure air source and the fuel cell stack is sequentially connected with a first three-way valve, a first pressure reducing valve, a first pressure sensor, a first filter, an air flow controller, a first flow sensor, a first bypass valve, a first humidifier, a first temperature sensor and a first humidity sensor; The pipeline between the high-pressure hydrogen source and the fuel cell stack is sequentially connected with a second three-way valve, a second pressure reducing valve, a second pressure sensor, a second filter, a multi-nozzle hydrogen injector, a second flow sensor, a second bypass valve, a second humidifier, a second temperature sensor and a second humidity sensor, and the fuel cell stack is connected to the second three-way valve through a hydrogen recovery system; The first three-way valve is connected to the second three-way valve via a pipeline, and the nitrogen source is connected to the first three-way valve and the second three-way valve via a connecting pipeline; The fuel cell stack is connected to the first radiator and the second radiator through pipelines. The output end of the first radiator is connected to the fuel cell stack through the first coolant storage tank, the first valve, the heater, the third temperature sensor, and the electronically controlled circulating water pump in sequence. The output end of the second radiator is connected to the fuel cell stack through the second coolant storage tank, the second valve, the first valve, the heater, the third temperature sensor, and the electronically controlled circulating water pump in sequence.

5. The fuel cell stack durability accelerated testing device according to claim 4, characterized in that: A first bypass pipeline is connected between the first bypass valve and the first temperature sensor, a second bypass pipeline is connected between the second bypass valve and the second temperature sensor, and a third bypass pipeline is connected between the second valve and the heater.

6. The fuel cell stack durability accelerated testing device according to claim 4, characterized in that: The first heat sink and the second heat sink are connected to a first electronic fan and a second electronic fan respectively.

7. The fuel cell stack durability accelerated testing device according to claim 4, characterized in that: The high-pressure air source, nitrogen source and high-pressure hydrogen source are respectively connected to a first manual safety valve, a second manual safety valve and a third manual safety valve through pipelines.

8. The fuel cell stack durability accelerated testing device according to claim 4, characterized in that: A data acquisition and control system is also provided, which is connected to each detector group and electronic load, electrochemical workstation and alarm device through connecting lines, and the alarm device is connected to the fuel cell stack.

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