A fuel cell thermal characteristics testing system and method using an infrared thermal imager and coupled thermocouples for combined temperature measurement

Abstract

The present invention discloses a fuel cell thermal characteristics testing system and method for combined temperature measurement using an infrared thermal imager and coupled thermocouples. The system includes components such as a fuel cell engine, a cooling and heat dissipation circuit, a thermal characteristics testing device, an electronic load and its control instrument, and a data acquisition device. The testing system can accurately measure the key thermophysical parameters of the fuel cell and the main operating parameters of the cooling and heat dissipation system in real time under steady-state and dynamic conditions, and then analyze the heat generation and heat dissipation characteristics of the fuel cell. The testing system also uses a thermal characteristics testing device based on an infrared thermal imager and coupled thermocouples to test the temperature distribution of the fuel cell stack. It can quickly locate the key thermal management areas in the stack and test and evaluate the temperature consistency between the units in the stack. It is particularly suitable for the research and development and evaluation of thermal management technologies for future high-power, full-operation fuel cell engines.

Description

Technical Field

[0001] The present invention relates to the field of testing of hydrogen fuel cell engines for vehicles, and in particular to a thermal characteristic testing system and method for a hydrogen fuel cell engine. Background Art

[0002] The world is currently undergoing a "clean, low-carbon, safe, and efficient" energy transformation. The trend toward energy conservation and emission reduction has given rise to a sustainable hydrogen economy. Fuel cells, as efficient and clean electrochemical engines, are considered the most promising new energy power system, and their research and development technology continues to advance.

[0003] Fuel cell engines are composed of hundreds of stacked proton exchange membrane cells. During operation, approximately half of their energy is dissipated as heat. Numerous studies have shown that the performance and lifespan of fuel cell engines are significantly affected by the stack's operating temperature and temperature uniformity. Therefore, thermal management is crucial to ensuring efficient and stable operation of fuel cell engines.

[0004] In recent years, companies have continued to develop high-power products, with each of these new products boasting high power, long life, and high power density. Developing high-power, full-load fuel cell engines requires overcoming bottlenecks in thermal management technology, facing challenges such as improving heat dissipation efficiency, enhancing temperature control, ensuring temperature uniformity, and increasing waste heat utilization.

[0005] The research and development of thermal management technology is based on the laws of thermal state changes of the management object. Breakthroughs in thermal management technology require knowledge of the thermal characteristics of fuel cell engines, and the steady-state and transient changes of key thermal characteristic parameters of fuel cell engines under different operating conditions as data support. Existing automotive fuel cell engines are constantly innovating in the direction of high power and variable loads, while high-power fuel cells with a large increase in the number of single cells face the thermal management problem of poor temperature consistency of the stack. In the field of fuel cell engine thermal management research, domestic and foreign scholars have conducted corresponding research on the thermal characteristics of fuel cell engines through modeling simulation and experimental testing. However, existing research is mostly based on the analysis of system heat generation and heat dissipation under steady-state conditions. The thermal characteristics of fuel cell engines mastered by existing research institutes are difficult to meet the latest needs of subsequent high-power fuel cell engine thermal management development, and existing test equipment is also unable to meet the development needs of advanced thermal management technologies for high-power, full-operating fuel cells. There are mainly the following deficiencies:

[0006] 1. There is a lack of experimental research on the system heat dissipation characteristics of high-power fuel cells under steady-state operation and variable load conditions;

[0007] 2. The temperature variation patterns of each unit inside the fuel cell stack when the load of a high-power fuel cell engine changes are not yet clear. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the prior art and provide a fuel cell thermal characteristics testing system and method using an infrared thermal imager and coupled thermocouples for combined temperature measurement. The technical solutions provided by the present invention are as follows:

[0009] The present invention provides a fuel cell thermal characteristics test system for combined temperature measurement using an infrared thermal imager and a coupled thermocouple, which includes a fuel cell engine, a cooling and heat dissipation circuit, a thermal characteristics test device, an electronic load and its control instrument, and a data acquisition device;

[0010] The fuel cell engine includes a fuel cell, a hydrogen supply circuit for supplying anode hydrogen to the fuel cell, an air supply circuit for supplying cathode air to the fuel cell, a voltage inspection device, and an FCU controller. The hydrogen supply circuit and the air supply circuit are respectively connected to the fuel cell. The voltage inspection device monitors the output voltage of each single fuel cell and transmits the data to the FCU controller. The FCU controller monitors and controls the actual operating status of the fuel cell engine in real time.

[0011] The cooling and heat dissipation circuit is connected to the fuel cell and is used to dissipate the heat generated when the fuel cell is working and maintain the operating temperature between 70 and 85°C; the cooling and heat dissipation circuit includes a cooling water pump, a main radiator, a deionizer, a compensation water tank, and a PTC heater; the cooling water pump, the main radiator, and the deionizer are connected in sequence through a cooling water pipeline, and the two ends of the cooling water pipeline are respectively connected to the cooling water inlet and outlet of the fuel cell heat dissipation jacket to form a large loop, and the compensation water tank is connected to the cooling water pipeline through the inlet and outlet pipes for pipeline water replenishment; the PTC heater is connected to the cooling water pipeline through a pipeline, and the PTC heater is connected to the main radiator in parallel; a cooling water outlet temperature sensor is installed at the cooling water outlet of the fuel cell heat dissipation jacket, and a cooling water inlet temperature sensor is installed at the cooling water inlet of the fuel cell heat dissipation jacket; a circulating cooling water flow meter is installed on the cooling water pipeline;

[0012] The thermal characteristics testing device includes an overhead infrared thermal imager and a coupled thermocouple array attached to the surface of the fuel cell. The infrared thermal imager is used to comprehensively detect the surface temperature distribution of the fuel cell, and the coupled thermocouple array is used to correct the temperature measurement value of the infrared thermal imager and measure the temperature value of the characteristic area.

[0013] The electronic load and its control instrument are connected to the fuel cell, and the electronic load and its control instrument feed the current output by the fuel cell back to the power grid, control the operating current of the fuel cell engine in a constant current mode, and measure the output performance parameters of the fuel cell engine in real time;

[0014] The data acquisition device is used to obtain the data signals converted and output by the thermocouple array and each sensor and communicate with the FCU controller.

[0015] As a preferred embodiment of the present invention, the hydrogen supply circuit includes a hydrogen source connected in sequence, a hydrogen delivery pipeline connecting the hydrogen source and the hydrogen inlet of the fuel cell, and an anode hydrogen flowmeter, a hydrogen circulation pump and an anode hydrogen temperature sensor arranged in sequence on the hydrogen delivery pipeline.

[0016] As a preferred embodiment of the present invention, the air supply circuit includes an air pipeline, and an air filter, an air compressor, an intercooler, a humidifier, a cathode air flow meter, and a cathode air temperature sensor arranged in sequence on the air pipeline; the air compressor is equipped with an auxiliary radiator for assisting the air compressor in heat dissipation.

[0017] As a preferred embodiment of the present invention, the coupled thermocouple array is arranged on the fuel cell to measure the temperature values of the fuel cell insulation layer, the first and last single cells, the guide area, the current collecting area, the center of the stack and the local high temperature area;

[0018] The coupled thermocouple array adopts a small temperature difference measurement method based on coupled thermocouples to directly measure the temperature difference thermoelectric potential, thereby reducing the temperature transmission error and the positive and negative deviations of the thermocouples.

[0019] As a preferred solution of the present invention, a cathode exhaust temperature sensor is provided at the tail discharge of the fuel cell stack to monitor the drain and exhaust temperatures of the fuel cell.

[0020] As a preferred embodiment of the present invention, the electronic load and its control instrument include an inverter circuit module, a main controller, current and voltage sensors, a transformer, and a grid synchronization signal; the inverter circuit module performs DC / DC boost conversion on the current output by the fuel cell engine, and then converts the output DC power into AC power synchronized with the AC grid via a transformer according to the grid synchronization signal, so that it can be incorporated into the AC grid for consumption and utilization, thereby achieving high efficiency and energy saving; the main controller is respectively connected to the current and voltage sensors and the inverter circuit module, and the main controller is used to monitor the power output of the fuel cell engine and implement load power regulation of the load, select constant current or constant voltage mode, and obtain AC grid synchronization signal.

[0021] The present invention also provides a method for testing the fuel cell thermal characteristics test system using the above-mentioned infrared thermal imager and coupled thermocouples for combined temperature measurement, which comprises the following steps:

[0022] Before the test begins, turn on the thermal imager, set the parameters according to the environmental conditions, check the connection of the thermocouple array, and then perform a temperature test on the fuel cell;

[0023] During the test, cooling water inlet temperature sensors were installed at the inlet and outlet of the fuel cell cooling water to measure the cooling water temperature, and a circulating cooling water flow meter was installed in the pipeline to measure the cooling water circulation flow rate. Combined with the ambient temperature value measured by the temperature sensor in the environment, the heat generation and heat dissipation characteristics of the fuel cell can be quantitatively calculated, thereby obtaining the heat generation power of the fuel cell under different operating conditions;

[0024] A cathode exhaust temperature sensor is installed at the tail of the fuel cell stack to monitor the drainage and exhaust temperatures of the fuel cell. A cathode inlet temperature sensor is installed in the air supply circuit to monitor the air inlet temperature. An anode inlet temperature sensor is installed in the hydrogen supply circuit to monitor the hydrogen inlet temperature. Combined with the air flow measured by the cathode inlet flowmeter, a simple estimate of the heat dissipation value of the fuel cell drainage and exhaust can be made.

[0025] The electronic load and its control instrument are equipped with current and voltage sensors to measure the power output of the fuel cell in real time. The anode inlet flow meter is installed in the hydrogen supply circuit to test the hydrogen consumption of the fuel cell. The heat dissipation value calculated by the cooling and heat dissipation circuit is combined with the estimated heat dissipation value of the drainage and exhaust gas to analyze the energy flow of the fuel cell engine, thereby determining the power conversion efficiency of the tested fuel cell engine.

[0026] From the start-up process of the fuel cell to the stable operation of the stack under various operating conditions and the switching between various operating conditions, the thermal characteristics test system uses graphical curves to intuitively display the changing trends of the values of each temperature measurement point, and at the same time calculates and analyzes the heat generation and energy flow of the fuel cell; at the same time, the temperature distribution on the fuel cell surface is monitored and analyzed through the infrared image displayed by the infrared thermal imager and the temperature values measured by the thermocouple array.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. Based on the development trend of high-power and full-operating-condition automotive fuel cell engines, the present invention designs a test system that can comprehensively and accurately measure the thermal characteristics of fuel cells. Various sensors with good adaptability and various powerful test instruments are selected, and a data acquisition system based on virtual instruments is used to accurately and efficiently collect various data information in real time for subsequent analysis and calculation.

[0029] 2. The present invention can comprehensively and accurately measure the temperature distribution on the surface of the fuel cell. The designed thermal characteristics test system can, while photographing or recording the changes in the infrared image of the fuel cell, use the temperature values measured by the thermocouple array to correct the infrared values and further accurately monitor the temperature changes in key parts.

[0030] In summary, the present invention provides a technical solution for a thermal characteristics testing system suitable for high-power automotive fuel cell engines. On the basis of real-time measurement and analysis of the overall heat generation and dissipation characteristics of the fuel cell, an infrared thermal imager and a coupled thermocouple array are used to test and evaluate the temperature consistency between each single cell unit of the fuel cell, in order to cope with the new challenges posed by the high-power and variable load development trend of automotive fuel cell engines for thermal management. It aims to provide testing means and data basis for the research of advanced thermal management technologies such as precise temperature control, waste heat utilization, and improved temperature uniformity, which is of great significance for promoting energy saving and high efficiency of fuel cell vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a structural schematic diagram of a specific embodiment of the present invention;

[0032] Figure 2 Shown is a hardware architecture design diagram of an embodiment;

[0033] Figure 3 Shown is a diagram of the arrangement of measurement points of a coupled thermocouple array according to an embodiment;

[0034] Description of reference numerals:

[0035] 1- Air filter, 2- Centrifugal air compressor, 3- Intercooler, 4- Humidifier, 5- Auxiliary radiator, 6- Infrared thermal imager, 7- Deionizer, 8- Cathode inlet flow meter, 9- Cathode inlet temperature sensor, 10- Cooling water inlet temperature sensor, 11- Circulating cooling water flow meter, 12- Fuel cell stack, 13- Thermocouple array, 14- PTC heater, 15- Main radiator, 16- Hydrogen circulation pump, 17- Anode inlet flow meter, 18- Anode inlet temperature sensor, 19- Cooling water outlet temperature sensor, 20- Hydrogen source, 21- Stack tail exhaust, 22- Cathode exhaust temperature sensor, 23- Compensating water tank, 24- Cooling water pump, 25- Electronic load and its control instrument, 26- AC power grid. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. To make the drawings more concise and intuitive, each figure only schematically shows the parts related to the present invention, omitting some system structures that are not closely related to the present invention. They do not represent the complete structure of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] In the description of the present invention, it should be noted that the specific models of various sensors are only preferred embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can choose other different types of sensors to test the corresponding parameters and obtain other implementation methods.

[0038] In the description of the present invention, it should be understood that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be internal communication between two components; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In response to the problems of the lack of experimental research on the thermal characteristics of existing fuel cells under the development trend of high power and the unknown law of temperature difference change of single battery cells, the present invention provides a thermal characteristic testing system that combines an infrared thermal imager and a coupled thermocouple to test the surface temperature distribution of fuel cells. It aims to provide testing means and data basis for the research of advanced thermal management technologies such as precise temperature control, waste heat utilization, and improved temperature uniformity of high-power fuel cells, which is of great significance for promoting energy saving and high efficiency of fuel cell vehicles.

[0040] A structural diagram of a preferred embodiment of the present invention is shown in FIG. Figure 1 As shown, the hardware architecture design is as follows Figure 2 As shown, the thermocouple array measurement points are arranged as follows Figure 3 shown.

[0041] The fuel cell thermal characteristics test system for combined temperature measurement using an infrared thermal imager and a coupled thermocouple of the present invention comprises: a fuel cell engine, a cooling and heat dissipation circuit, a thermal characteristics test device, an electronic load and its control instrument, and a data acquisition device;

[0042] The fuel cell engine includes a fuel cell (i.e., a fuel cell stack 12), a hydrogen supply circuit for supplying anode hydrogen to the fuel cell, an air supply circuit for supplying cathode air to the fuel cell, a voltage inspection device, and an FCU controller. The hydrogen supply circuit and the air supply circuit are respectively connected to the fuel cell. The voltage inspection device monitors the output voltage of each single fuel cell and transmits the data to the FCU controller.

[0043] The air supply circuit for supplying cathode air to the fuel cell includes an air pipeline, and an air filter 1, an air compressor 2, an intercooler 3, a humidifier 4, a cathode air flow meter 8, and a cathode air temperature sensor 9 arranged in sequence on the air pipeline; the air compressor is equipped with an auxiliary radiator 5 for assisting the air compressor in heat dissipation.

[0044] The hydrogen supply circuit for supplying anode hydrogen to the fuel cell includes a hydrogen source 20 connected in sequence, a hydrogen delivery pipeline connecting the hydrogen source 20 and the hydrogen inlet of the fuel cell, and an anode hydrogen flowmeter 17, a hydrogen circulation pump 16 and an anode hydrogen temperature sensor 18 arranged in sequence on the hydrogen delivery pipeline.

[0045] The cooling and heat dissipation circuit is the core component of the thermal characteristic test system. It plays the role of implementing the thermal management strategy to effectively control the operating temperature of the fuel cell stack and monitor key thermal characteristic parameters. The cooling and heat dissipation circuit is connected to the fuel cell and is used to dissipate the heat generated when the fuel cell is working; the cooling and heat dissipation circuit includes a cooling water pump 24, a main radiator 15, a deionizer 7, a compensation water tank 23, and a PTC heater 14; the cooling water pump 24, the main radiator 15, and the deionizer 7 are connected in sequence through a cooling water pipeline, and the two ends of the cooling water pipeline are respectively connected to the cooling water inlet and outlet of the fuel cell heat dissipation jacket to form a large loop. The compensation water tank 23 is connected to the cooling water pipeline through the inlet and outlet pipes for pipeline water replenishment; the PTC heater 14 is connected to the cooling water pipeline through a pipeline, and the PTC heater 14 is connected in parallel with the main radiator 15; a cooling water outlet temperature sensor 19 is installed at the cooling water outlet of the fuel cell heat dissipation jacket, and a cooling water inlet temperature sensor 10 is installed at the cooling water inlet of the fuel cell heat dissipation jacket; a circulating cooling water flow meter 11 is installed on the cooling water pipeline.

[0046] The electronic load and its control instrument are used to control the working current of the fuel cell and consume the electric energy generated by the fuel cell. The electronic load and its control instrument are connected to the fuel cell and are used to monitor and consume the electric energy output of the fuel cell; the electronic load and its control instrument include an inverter circuit module, a main controller, a current and voltage sensor, a transformer and a grid synchronization signal; the inverter circuit module performs DC / DC boost conversion on the current output by the fuel cell engine, and then converts the output DC power into AC power synchronized with the AC grid through the transformer according to the grid synchronization signal, so that it can be incorporated into the AC grid 26 for consumption and utilization, which is efficient and energy-saving; the main controller is connected to the current and voltage sensor, and the current and voltage sensor is connected to the inverter circuit module. The main controller is used to monitor the electric energy output of the fuel cell engine and implement load power regulation, select constant current or constant voltage mode, obtain AC grid synchronization signal and other test control functions.

[0047] The thermal characteristics test device is a key component of the test system, including an infrared thermal imager 6 and a thermocouple array 13. The infrared thermal imager 6 is used to comprehensively measure the thermal state of the fuel cell surface. At the same time, the coupled thermocouple array 13 is used to correct the temperature measurement data of the infrared thermal imager and measure the precise temperature values of key locations such as the insulation layer, the first and last single cells, the guide area, the current collecting area, the center of the stack, and the local high-temperature area.

[0048] In one embodiment of the present invention, Figure 1 As shown, a cooling water inlet temperature sensor 10 is set at the inlet and outlet of the fuel cell cooling water to measure the cooling water temperature, and a circulating cooling water flow meter 11 is set in the pipeline to test the cooling water circulation flow. Combined with the ambient temperature value measured by the temperature sensor in the environment, the heat generation and heat dissipation characteristics of the fuel cell can be quantitatively calculated, thereby obtaining the heat generation power of the fuel cell under different working conditions.

[0049] In this preferred embodiment, if Figure 1 As shown, a cathode exhaust temperature sensor 22 is provided at the tail row of the fuel cell stack to monitor the drainage and exhaust temperatures of the fuel cell, a cathode inlet temperature sensor 9 is provided in the air supply circuit to monitor the air inlet temperature, and an anode inlet temperature sensor 18 is provided in the hydrogen supply circuit to monitor the hydrogen inlet temperature. Combined with the air flow measured by the cathode inlet flowmeter 8, a simple estimate of the heat dissipation value of the drainage and exhaust of the fuel cell can be made.

[0050] In this preferred embodiment, if Figure 1 As shown, the electronic load and its control instrument are equipped with a current and voltage sensor 26, which can measure the electrical energy output of the fuel cell in real time. The anode inlet flow meter 17 is installed in the hydrogen supply circuit to test the hydrogen consumption of the fuel cell. The heat generation and heat dissipation value calculated by the cooling and heat dissipation circuit is combined with the estimated drainage and exhaust heat dissipation value to perform energy flow analysis on the fuel cell engine, thereby obtaining the electrical energy conversion efficiency of the tested fuel cell engine.

[0051] In this preferred embodiment, sensors that are easy to install, have high precision, and good stability are selected based on the test function requirements, performance indicators, and test environment. Among them, based on the temperature value and precision requirements of the temperature measurement object, the temperature sensor in the test system uses the inexpensive and highly sensitive OMEGA brand 5TC series T-type thermocouple, specifically the model TT-T-36-SLE, and uses a thermocouple with a wire diameter of 36. The thermocouple has a thin wire diameter, a small measuring point, and a small thermal inertia. The test accuracy can reach ±0.4%, and it has the advantages of good linearity and high stability. The circulating cooling water flow meter 11 uses the Jiangsu Yichen Industrial model LGWY-50 turbine flow meter with a quick-release chuck to test the flow value of the circulating cooling water. Its range can meet the large flow of fuel cell cooling water. , 0.5 level accuracy, high precision and very easy to install; the hydrogen flowmeter adopts ALICAT's thermal gas mass flowmeter, which is small in size, convenient and accurate in measurement; in addition, the electronic load in this preferred embodiment uses Kewell's KDLF300-800-1000 fuel cell dedicated DC feedback electronic load, which can apply load to the fuel cell in various ways such as constant voltage, constant current and constant power. It is suitable for high-voltage, high-current, high-power fuel cell engines with a maximum power of up to 300kW, and can integrate the electric energy output by the fuel cell into the power grid for utilization, saving energy.

[0052] In this preferred embodiment, the hardware architecture of the data acquisition device based on the virtual instrument system is designed according to the type of sensor and the type of signal it outputs. Figure 2 As shown in the figure, the data acquisition device uses an 8-slot CompactDAQ Ethernet chassis, model cDAQ-9188, designed by National Instruments for remote measurement. The NI-9214 thermocouple input module acquires and processes the voltage signals output by T-type thermocouples, while the NI-9208 current input module acquires and processes the analog signals output by other sensors. The main controller issues control commands to components such as the fuel cell stack, air compressor, cooling water pump, and radiator electronic fan, thereby adjusting the fuel cell operating status or thermal management strategy. The infrared thermal imager is directly connected to the computer, displaying real-time thermal images and communicating with the test system via the RS232 protocol, transmitting values such as the global maximum temperature and the local maximum and minimum temperatures to the test system.

[0053] In this preferred embodiment, the measurement point arrangement positions of the thermocouple array are determined according to the two principles of correcting the temperature value measured by the thermal imager and monitoring the temperature of the key area on the surface of the fuel cell, such as Figure 3As shown in the figure. The upper measuring points 1-7 are used to calibrate the temperature values measured by the thermal imager. Measuring points a, b, c, d and measuring points A, B, C, D are respectively placed on the insulation layer and the first or last piece of the fuel cell. This is because the presence of the insulation layer and end plates creates special heat dissipation conditions for the first and last pieces of the single cell, often leading to poor performance issues such as low first piece temperature. Therefore, when arranging the measuring points of the thermocouple array, special attention is paid to changes in the surface temperature of the insulation layer and the first and last pieces of the single cell. The lower two groups of measuring points H, I, J, K and h, i, j, k are set at the common global maximum temperature to monitor changes in the maximum temperature of the fuel cell surface.

[0054] The following briefly describes the main test functions of the thermal characterization test system. Before testing begins, turn on the thermal imager, set the parameters according to environmental conditions, and check the connections of the thermocouple array before performing a temperature test on the fuel cell. From the start-up process of the fuel cell stack to its stable operation under various operating conditions and the process of switching between operating conditions, the thermal characterization test system uses graphs and curves to intuitively display the changing trends of the values at each temperature measurement point. It also calculates and analyzes the heat generation and energy flow of the fuel cell. Furthermore, the temperature distribution on the fuel cell surface is monitored and analyzed using the infrared image displayed by the infrared thermal imager and the temperature values measured by the thermocouple array.

[0055] This preferred embodiment of the present invention conducted a thermal characteristics test on a fuel cell engine with a rated output power of 120kW. Application verification proved that the test system can basically realize the required functions, work stably and reliably, and can timely and intuitively discover areas in the fuel cell stack where thermal management is more difficult or the temperature is abnormal. It points out the optimization direction for the thermal management of high-power fuel cell engines and provides data support, which is helpful for the development of advanced thermal management technologies such as precise temperature control and waste heat utilization, and is of great significance for promoting energy saving and efficiency of fuel cell vehicles.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fuel cell thermal characteristics testing system using an infrared thermal imager and a coupled thermocouple for temperature measurement, characterized in that: Including fuel cell engine, cooling and heat dissipation circuit, thermal characteristics test equipment, electronic load and its control instrument and data acquisition equipment; The fuel cell engine includes a fuel cell, a hydrogen supply circuit for supplying anode hydrogen to the fuel cell, an air supply circuit for supplying cathode air to the fuel cell, a voltage inspection device, and an FCU controller. The hydrogen supply circuit and the air supply circuit are respectively connected to the fuel cell. The voltage inspection device monitors the output voltage of each single fuel cell and transmits the data to the FCU controller. The FCU controller monitors and controls the actual operating status of the fuel cell engine in real time. The cooling and heat dissipation circuit is connected to the fuel cell and is used to dissipate the heat generated when the fuel cell is working and maintain the operating temperature between 70 and 85°C; the cooling and heat dissipation circuit includes a cooling water pump, a main radiator, a deionizer, a compensation water tank, and a PTC heater; the cooling water pump, the main radiator, and the deionizer are connected in sequence through a cooling water pipeline, and the two ends of the cooling water pipeline are respectively connected to the cooling water inlet and outlet of the fuel cell heat dissipation jacket to form a large loop, and the compensation water tank is connected to the cooling water pipeline through the inlet and outlet pipes for pipeline water replenishment; the PTC heater is connected to the cooling water pipeline through a pipeline, and the PTC heater is connected to the main radiator in parallel; a cooling water outlet temperature sensor is installed at the cooling water outlet of the fuel cell heat dissipation jacket, and a cooling water inlet temperature sensor is installed at the cooling water inlet of the fuel cell heat dissipation jacket; a circulating cooling water flow meter is installed on the cooling water pipeline; The thermal characteristics testing device includes an overhead infrared thermal imager and a coupled thermocouple array attached to the surface of the fuel cell. The infrared thermal imager is used to comprehensively detect the surface temperature distribution of the fuel cell, and the coupled thermocouple array is used to correct the temperature measurement value of the infrared thermal imager and measure the temperature value of the characteristic area; the coupled thermocouple array is arranged on the fuel cell and is used to measure the temperature values of the fuel cell insulation layer, the first and last single cells, the guide area, the collecting area, the center of the stack and the local high-temperature area; the coupled thermocouple array adopts a small temperature difference measurement method based on coupled thermocouples to directly measure the temperature difference thermoelectric potential, thereby reducing the temperature transmission error and the positive and negative deviation of the thermocouple; a cathode exhaust temperature sensor is provided at the tail of the fuel cell stack to monitor the drainage and exhaust temperatures of the fuel cell; The electronic load and its control instrument are connected to the fuel cell, and the electronic load and its control instrument feed the current output by the fuel cell back to the power grid, control the operating current of the fuel cell engine in a constant current mode, and measure the output performance parameters of the fuel cell engine in real time; The data acquisition device is used to obtain the data signals converted and output by the thermocouple array and each sensor and communicate with the FCU controller.

2. The fuel cell thermal characteristics testing system for combined temperature measurement using an infrared thermal imager and coupled thermocouples as claimed in claim 1, characterized in that: The hydrogen supply circuit includes a hydrogen source connected in sequence, a hydrogen delivery pipeline connecting the hydrogen source and the hydrogen inlet of the fuel cell, and an anode hydrogen flowmeter, a hydrogen circulation pump and an anode hydrogen temperature sensor arranged in sequence on the hydrogen delivery pipeline.

3. The fuel cell thermal characteristics testing system for combined temperature measurement using an infrared thermal imager and coupled thermocouples as claimed in claim 1, characterized in that: The air supply circuit includes an air pipeline, and an air filter, an air compressor, an intercooler, a humidifier, a cathode air flow meter, and a cathode air temperature sensor arranged in sequence on the air pipeline; the air compressor is equipped with an auxiliary radiator for assisting the air compressor in dissipating heat.

4. The fuel cell thermal characteristics testing system for combined temperature measurement using an infrared thermal imager and coupled thermocouples as claimed in claim 1, characterized in that: The electronic load and its control instrument include an inverter circuit module, a main controller, current and voltage sensors, a transformer, and a grid synchronization signal; the inverter circuit module performs DC / DC boost conversion on the current output by the fuel cell engine, and then converts the output DC power into AC power synchronized with the AC grid via a transformer according to the grid synchronization signal, so that it can be incorporated into the AC grid for consumption and utilization, achieving high efficiency and energy saving; the main controller is respectively connected to the current and voltage sensor and the inverter circuit module. The main controller is used to monitor the power output of the fuel cell engine and implement load power regulation of the load, select constant current or constant voltage mode, and obtain AC grid synchronization signals.

5. A method for testing a fuel cell thermal characteristics test system using an infrared thermal imager and coupled thermocouples for combined temperature measurement according to claim 1, characterized in that: The steps include: Before the test begins, turn on the thermal imager, set the parameters according to the environmental conditions, check the connection of the thermocouple array, and then perform a temperature test on the fuel cell; During the test, cooling water inlet temperature sensors were installed at the inlet and outlet of the fuel cell cooling water to measure the cooling water temperature, and a circulating cooling water flow meter was installed in the pipeline to measure the cooling water circulation flow rate. Combined with the ambient temperature value measured by the temperature sensor in the environment, the heat generation and heat dissipation characteristics of the fuel cell can be quantitatively calculated, thereby obtaining the heat generation power of the fuel cell under different operating conditions; A cathode exhaust temperature sensor is installed at the tail of the fuel cell stack to monitor the drain and exhaust temperatures of the fuel cell. A cathode inlet temperature sensor is installed in the air supply circuit to monitor the air inlet temperature. An anode inlet temperature sensor is installed in the hydrogen supply circuit to monitor the hydrogen inlet temperature. Combined with the air flow measured by the cathode inlet flow meter, a simple estimate of the heat dissipation value of the fuel cell drain and exhaust can be made. The electronic load and its control instrument are equipped with current and voltage sensors to measure the power output of the fuel cell in real time. The anode inlet flow meter is installed in the hydrogen supply circuit to test the hydrogen consumption of the fuel cell. The heat dissipation value calculated by the cooling and heat dissipation circuit is combined with the estimated heat dissipation value of the drainage and exhaust gas to analyze the energy flow of the fuel cell engine, thereby determining the power conversion efficiency of the tested fuel cell engine. From the start-up process of the fuel cell to the stable operation of the stack under various operating conditions and the switching between various operating conditions, the thermal characteristics test system uses graphical curves to intuitively display the changing trends of the values of each temperature measurement point, and at the same time calculates and analyzes the heat generation and energy flow of the fuel cell; at the same time, the temperature distribution on the fuel cell surface is monitored and analyzed through the infrared image displayed by the infrared thermal imager and the temperature values measured by the thermocouple array.

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