Fuel cell multi-physical field on-line testing device and method

Abstract

The invention relates to a fuel cell multi-physical field on-line testing device and method. The fuel cell multi-physical field on-line testing device comprises a current density impedance measuring plate, a partition plate and a multi-physical field measuring plate which are sequentially stacked, the electric density impedance measuring plate is provided with multiple partitions in an array in the plate surface direction and three layers with different functions in the plate thickness direction, a cathode gas flow field is arranged on the upper surface layer, first conductive metal which is insulated from each other is arranged on a flow channel ridge of the cathode gas flow field, resistors in an array are arranged on the middle layer, and the first conductive metal and the second conductive metal are arranged on the middle layer. The channel is connected with the two ends of the resistor, and second conductive metal is arranged on the lower surface layer; a first current channel and a second current channel are arranged between the upper surface layer and the lower surface layer, the first current channel and the second current channel are arranged in a staggered mode, one end is insulated from the conductive metal, and the resistor is connected with the first current channel and the second current channel. Compared with the prior art, the device can replace a bipolar plate to be assembled at any battery, the multi-physical field distribution of the fuel cell stack is measured on line, and the test is flexible.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells and relates to a multi-physical field online testing device and method for fuel cells. Background Art

[0002] Proton exchange membrane fuel cells are a promising electrochemical energy conversion device that can directly convert chemical energy stored in fuel into electrical energy through electrochemical reactions. In order to meet the output voltage and power requirements, fuel cells are usually composed of multiple bipolar plates and membrane electrodes alternately connected in series to form a stack, with a single-section reaction area of ​​up to 200-500cm 2 The internal reaction of fuel cells involves multiple physical fields such as temperature, humidity, and current density. The large reaction area often causes uneven distribution of various physical fields inside the battery, which in turn causes problems such as water blockage, drying, and anode and cathode starvation. At the same time, there are performance differences between different single cells in the stack. During the operation of the stack, a cell may fail. Therefore, obtaining the distribution of multiple physical fields of each cell inside the fuel cell is of great guiding significance for fuel cell performance analysis and fault diagnosis.

[0003] The uniformity of fuel cell reactions is closely related to the distribution of multiple physical fields such as temperature, humidity, current density, impedance, etc. There are currently a variety of research methods for measuring the distribution of multiple physical fields inside fuel cells: Analyzing the distribution of physical fields inside fuel cells through finite element analysis requires huge computing power support, has high model requirements, and has low computational efficiency; data-driven prediction of multiple physical field distribution requires a large amount of fuel cell operation data, and occasional failures are still difficult to accurately predict; in contrast, using an embedded in-situ online measurement system to measure the multiple physical fields of fuel cells is more reliable and has more practical value.

[0004] Chinese patent CN110780213A discloses a current density detection composite plate, which measures a relatively single physical quantity; Chinese patent CN109301289A and Chinese patent CN103245920A disclose test devices for temperature, pressure and current density, temperature, and impedance, respectively, but the devices are only applied to a single battery, which is quite different from the application scenario of multiple fuel cell batteries connected in series in a stack; Chinese patent CN113030736A discloses an integrated measurement equipment for multiple physical quantities such as temperature, current density, humidity, and impedance, but the test device is connected to the fuel cell end plate and is only applicable to the outermost battery in the fuel cell stack, and the battery status in the middle of the stack cannot be obtained.

[0005] In addition, there are differences between the measurement sites of various sensors on the embedded measurement board and the physical field distribution of the fuel cell membrane electrode, and the heating of the internal components of the measurement board causes local hot spots, which affects the measurement accuracy of various physical quantities such as current density. The physical field distribution measurement of large-area fuel cells will inevitably have a large number of measurement partitions. The number of signals for each additional physical quantity measured is doubled, which puts high demands on the acquisition capability of the signal acquisition equipment. Under the condition of limited number of channels of the signal acquisition equipment, how to use the existing signal acquisition equipment to achieve simultaneous measurement of multiple partitions and multiple physical fields of large-area fuel cells is an urgent problem to be solved.

[0006] Patent CN111308359A discloses a multifunctional online test system for large-area fuel cells, including a multifunctional measuring board, a first data acquisition module, an excitation generator, a load circuit and a computer. The multifunctional measuring board is installed on the fuel cell as a cathode plate or an anode plate, and the load circuit is respectively connected to the multifunctional measuring board and another monopolar plate of the fuel cell corresponding to the multifunctional measuring board, and the excitation generator is connected between the multifunctional measuring board and the monopolar plate. The multifunctional measuring board includes multiple independent test partitions, each of which is provided with a number of sensor measurement holes, and the sensor is connected to the first data acquisition module. The plates of the independent test partitions are respectively connected to the excitation generator and the load circuit, and the computer is connected to the first data acquisition module and the excitation generator. However, the test subject of the patent lacks the relevant cooling water flow channel, and the battery current cannot be further conducted to the next battery after being collected, which limits the use of the measuring board in large-area multi-section stacks, and the method of drilling holes on the PCB board to embed the sensor has high sealing requirements and difficult processing; at the same time, the patent collects the impedance separately from other physical signals, and uses two switches to control whether the signal is collected or not, which greatly increases the complexity and control difficulty of the system.

[0007] Patent CN117174963A discloses a multi-physical quantity in-situ monitoring device for proton exchange membrane fuel cells, including a cathode end plate, a cathode insulating plate, a cathode test plate, a membrane electrode assembly, an anode test plate, an anode insulating plate and an anode end plate, which are assembled in sequence from left to right; the cathode end plate and the anode end plate are used to fix and encapsulate the entire proton exchange membrane fuel cell; the cathode insulating plate and the anode insulating plate are used to avoid direct contact between the end plate and the test plate to improve safety; the cathode test plate and the anode test plate can both realize online monitoring of the partitioned current density and the temperature and humidity distribution. However, this patent also lacks the means of cooling and conducting the current to the next battery, and cannot be applied to a battery stack with multiple batteries in series; this patent uses optical fiber to measure temperature and humidity, and the optical fiber arrangement requires trenching and burying on the measuring plate, which is complicated to process. At the same time, standard resistors are used as electrical density measurement elements, which occupy a large amount of board area and the structure is not compact enough. Summary of the invention

[0008] The purpose of the present invention is to provide a fuel cell multi-physical field online testing device and method in order to overcome at least one defect of the above-mentioned prior art. The present invention can replace the bipolar plate and be installed at any battery cell to perform online measurement of the multi-physical field distribution of the fuel cell stack, and the test is flexible.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] One of the technical solutions of the present invention is to provide a multi-physical field online testing device for a fuel cell, the device comprises a main body of an electric impedance measurement plate, a partition plate and a multi-physical field measurement plate stacked in sequence, the electric impedance measurement plate and the multi-physical field measurement plate are provided with a water flow field, the electric impedance measurement plate is provided with an array of resistors, the multi-physical field measurement plate is provided with an array of sensors, the main body is placed at the end cell or any cell in the middle of the fuel cell stack, and the measurement of multi-physical fields such as current density, temperature, humidity, impedance, etc. inside the flow channel or at the membrane electrode is realized;

[0011] The electrical impedance measurement board is divided into multiple partitions of an array in the board surface direction and three layers with different functions in the board thickness direction, wherein a cathode gas flow field is arranged on the upper surface layer, a first conductive metal insulated from each other is arranged on the flow channel ridge of the cathode gas flow field, an array of resistors and a channel connecting the two ends of the resistor are arranged on the middle layer, and a second conductive metal is arranged on the lower surface layer;

[0012] A first current channel is arranged between the first conductive metal of the flow channel ridge of the cathode gas flow field on the upper surface layer in a single partition and the lower surface layer of the electrical impedance measurement plate, and no second conductive metal is arranged at the connection between the lower surface layer and the first current channel for insulation, and a second current channel is arranged between the flow channel groove of the cathode gas flow field on the upper surface layer in the single partition and the second conductive metal of the lower surface layer, the first current channel and the second current channel are arranged alternately and one end is insulated from the conductive metal, and the resistor is connected to the first current channel and the second current channel, so that the current passes through the first conductive metal, the first current channel, the resistor, the second current channel and the second conductive metal in sequence.

[0013] Furthermore, each layer in each partition of the electrical impedance measurement plate is provided with an air hole corresponding to the sensor, and the corresponding position of the air hole is located in the flow channel groove of the cathode gas flow field;

[0014] The partition is divided into multiple partitions of an array in the direction of the plate surface, and is conductive. A mounting hole corresponding to the sensor is opened in each partition, and the size of the mounting hole is larger than that of the sensor.

[0015] As a preferred technical solution, a sealing groove is opened on the periphery of the electrical impedance measurement plate, and a sealing strip is filled in the sealing groove to seal and connect with adjacent plates.

[0016] As a preferred technical solution, a sealing groove is opened on the periphery of the partition plate, and a sealing strip is filled in the sealing groove to seal and connect with the adjacent plates.

[0017] Furthermore, the multi-physics field measurement board is divided into multiple partitions of the array in the board surface direction and three layers with different functions in the board thickness direction, wherein the upper surface layer is provided with an array of sensors and a third conductive metal, the middle layer is provided with a channel connecting the two ends of the sensor, the lower surface layer is provided with a cooling water flow field, and the flow channel ridges of the cooling water flow field are provided with a fourth conductive metal insulated from each other.

[0018] Furthermore, a signal channel is arranged between the flow channel grooves of the cooling water flow field of the upper surface layer and the lower surface layer in a single partition of the multi-physical field measurement board, and the third conductive metal is not arranged at the connection between the upper surface layer and the signal channel for insulation, and a third current channel is arranged between the third conductive metal of the upper surface layer and the fourth conductive metal of the flow channel ridge of the cooling water flow field of the lower surface layer in the single partition, the signal channel and the third current channel are arranged in isolation, and both ends of the signal channel are insulated from the conductive metal and connected to the sensor, so that the sensor transmits the measurement signal to the middle layer output through the surrounding signal channel, and transmits current between the third conductive metal and the fourth conductive metal through the third current channel.

[0019] Furthermore, when the device is used for the middle battery of the battery stack, the electric impedance measurement plate, the separator, the multi-physical field measurement plate and the monopolar plate stacked in sequence constitute a main body, and the main body is placed between a pair of membrane electrodes instead of the bipolar plate, and the bipolar plate is placed on the other side of the main body;

[0020] When the device is used for the end battery of the stack, the electrical impedance measurement plate, the separator and the multi-physical field measurement plate stacked in sequence constitute a main body, which is placed between the membrane electrode and the current collecting plate instead of the bipolar plate, and the membrane electrode is placed on the other side of the main body with the bipolar plate.

[0021] Furthermore, the monopolar plate is conductive, and a cooling water flow field and an anode gas flow field are respectively provided on both sides.

[0022] As a preferred technical solution, a sealing groove is opened on the periphery of the monopolar plate, and a sealing strip is filled in the sealing groove to seal and connect with the adjacent plates.

[0023] As a preferred technical solution, the current density measurement plate and the multi-physical field measurement plate adopt a multi-layer PCB board, the conductive metal adopts surface copper plating, the current channel and the signal channel adopt through holes, and the partition and the monopolar plate are made of graphite plates or metal plates with good conductivity through machining.

[0024] As a preferred technical solution, the sensor is selected from one or more sensors for fuel cell multi-physical fields, including temperature and humidity sensors, oxygen concentration sensors, and endoscopes.

[0025] When the device is used for the battery in the middle of the battery stack, the battery current will flow through the membrane electrode, the first conductive metal on the surface of the electric impedance measurement plate, the first current channel, the resistor, the second current channel, the second conductive metal on the lower surface, the separator, the third conductive metal on the surface of the multi-physical field measurement plate, the third current channel, the fourth conductive metal on the lower surface, and the monopolar plate in sequence, and then reach the next membrane electrode;

[0026] When the device is used for the battery at the end of the battery stack, the battery current will flow through the membrane electrode, the first conductive metal on the surface of the electrical impedance measurement plate, the first current channel, the resistor, the second current channel, the second conductive metal on the lower surface, the partition, the third conductive metal on the surface of the multi-physical field measurement plate, the third current channel, the fourth conductive metal on the lower surface, and then directly enter the current collecting plate.

[0027] The device contains a water flow field to ensure normal water supply to the battery.

[0028] The main body is provided with a cathode gas flow field, a cooling water flow field, an anode gas flow field and a current conduction path combined with the flow fields. While implementing multi-physical field measurements, it meets the operational requirements of current conduction and water and gas supply inside the battery stack, ensuring that the device can measure any battery inside or at the end of the battery stack.

[0029] Furthermore, the inlet and outlet structures of the water flow field are different from those of ordinary electrode flow fields. The introduction of the device will change the distribution of water vapor in the battery cell. The device selects the inlet form, including a step structure or a distribution area flow channel, according to the change in the water flow field on the measuring plate compared with the normal electrode flow resistance, and adjusts the geometric dimensions of the step inlet or the distribution area to reduce the impact of the device on the water flow field and the distribution of the two-electrode gas and cooling water, and avoid the problem of uneven water vapor distribution caused by the embedding of the main body.

[0030] As a preferred technical solution, due to the existence of a draft angle in the actual bipolar plate flow field, the flow resistance of the bipolar plate flow field is smaller than that of the measuring plate flow field. In order to compensate for the larger influence of the measuring plate flow resistance, the inlet and outlet structures of the cathode gas flow field, cooling water flow field and anode gas flow field cancel the inlet step structure and adopt a planar rectangular distribution area flow channel to reduce the change in stack flow resistance caused by the device and the impact on the distribution of cathode gas, cooling water and anode gas inside the battery.

[0031] Furthermore, the device also includes a data acquisition module, a computer, a load and an excitation generator peripheral device, the measurement signals of the electric impedance measurement board and the multi-physical field measurement board are imported into the data acquisition module, and finally uploaded to the computer, and the load and the excitation generator are connected to the two ends of the battery stack, the computer processes the measurement signal, controls the load state, and controls the disturbance input of the excitation generator, and the peripheral device can correct the multi-physical field test signal obtained by the main body, so as to obtain the real distribution of the multi-physical field in the membrane electrode area;

[0032] The device also includes a peripheral device of a signal control switch, which is arranged between the main body and the data acquisition module and is controlled by a computer. The measurement signals of the electrical impedance measurement board and the multi-physical field measurement board are introduced into the data acquisition module through the signal control switch. The computer controls the opening and closing of the signal control switch. The peripheral device can realize the partitioning of different areas of the flow field or the sequential data acquisition of different physical fields, thereby realizing the rapid measurement of large-area multi-physical fields.

[0033] The data acquisition module respectively collects the voltage drop across the resistor in each partition of the electric impedance measurement board, and the temperature and humidity of the reaction gas passing through the pores of the electric impedance measurement board and the mounting holes of the partition detected by the sensor in each partition of the multi-physical field measurement board, and uploads the voltage drop and temperature and humidity to the computer for correction and imaging processing to obtain the current density, temperature, and humidity distribution.

[0034] The data acquisition module acquires the voltage response between the first current channel in each partition and the anode of the bipolar plate on the other side of the membrane electrode on one side of the electrical impedance measurement plate when the excitation generator inputs a disturbance, and transmits the voltage response to the computer for processing to obtain the partition impedance distribution.

[0035] The computer automatically adjusts the working state of the load according to the measured physical field distribution.

[0036] The signal measured by the main body is collected by the data acquisition module and uploaded to the computer after passing through the signal control switch, and is presented to the user after calculation, correction and visualization. At the same time, the computer appropriately adjusts the load of the fuel cell stack according to the measurement results to adapt to the current working condition of the fuel cell stack.

[0037] The computer calculates the partition current density according to the voltage drop uploaded by the data acquisition module, calculates the partition impedance according to the response signal, corrects the temperature and humidity measurement results of the test site to the temperature and humidity at the membrane electrode, and finally presents the test results to the user in a graphical form.

[0038] One of the technical solutions of the present invention is to provide a fuel cell multi-physical field online testing method, which uses the fuel cell multi-physical field online testing device for testing, and the method comprises the following steps:

[0039] The computer corrects the current density signal of the resistor under high temperature and the temperature signal of the sensor respectively, so as to reduce the influence of the heating of the resistor on the current density measurement and the influence of the installation position of the sensor on the temperature measurement, and obtain the current density and temperature distribution of the membrane electrode reaction area. The correction relationship comes from the experimental calibration and analytical model calculation.

[0040] Current density test: Due to the thermal effect of resistors, the actual temperature of the resistors during measurement is higher than the reaction temperature inside the fuel cell. The computer uses finite element calculation to obtain the corresponding relationship between the current density flowing through the resistors and the actual temperature of the resistors under the conditions of specific battery reaction temperature and cooling water temperature, and further obtains the corresponding relationship between the voltage drop across the resistors and the actual resistance value of the resistors, thereby calculating the current density of the resistors in each partition.

[0041] Temperature test: Due to the distance between the installation position of the sensor and the membrane electrode, there is a difference between the temperature of the gas reaching the measurement point and the temperature of the membrane electrode; the computer uses finite element calculation to obtain the relationship between the battery membrane electrode temperature t0, the temperature t1 measured by the temperature and humidity sensor, and the cooling water temperature t2. Based on the temperature t1 measured by the temperature and humidity sensor and the cooling water temperature t2, the membrane electrode temperature t0 in each partition is calculated;

[0042] Partition impedance test, through the excitation generator to apply sinusoidal micro-disturbance to each test partition of the fuel cell, the data acquisition module collects the frequency response signal of each partition in real time, and the computer calculates the AC impedance of each partition based on the response signal.

[0043] Furthermore, when the number of acquisition channels is insufficient, the measurement signals in each partition share one acquisition channel, and the user controls the opening and closing of the signal control switches of various physical quantities through a computer according to needs to achieve the measurement of a certain physical quantity; or, the opening and closing sequence and alternating frequency of the signal control switch are adjusted through a computer to achieve the sequential measurement of multiple physical fields in different areas of the flow field, ultimately completing the entire flow field test and adjusting the refresh frequency of the distribution image at the same time.

[0044] As a preferred technical solution, when the measured physical quantity signal is less than the number of channels of the data acquisition module, all signal control switches are closed; when the measured physical quantity signal is more than the number of channels of the data acquisition module, one acquisition channel is connected to multiple measurement signals, and the user controls the opening and closing of the signal control switch through a computer to realize the acquisition and measurement of specific physical quantity signals in a specific partition, or, by adjusting the signal control switch to cycle open and close, to realize simultaneous measurement of all multi-physical fields of the fuel cell stack.

[0045] As a preferred technical solution, the number of channels of the data acquisition module is m, and the number of partitions is n; when m>=4n, all signal control switches are closed, and the device simultaneously tests the current density, temperature, humidity, and impedance distribution of all partitions of the battery stack; when m<4n, one acquisition channel is connected to multiple measurement signals, and the user can freely adjust the closure of the signal control switch through the computer to control the number of partitions and the type of physical quantities collected by the data acquisition module, or, by adjusting the opening and closing sequence and switching frequency of the signal control switch, control the update sequence and refresh frequency of the multi-physical field visualization window.

[0046] The present invention provides a fuel cell multi-physical field online testing device, which can realize online measurement of the uneven distribution of multi-physical fields such as current density, temperature, humidity, high-frequency impedance, etc. inside a large-area fuel cell stack. The combined configuration of flow field, current channel and conductive metal is used to ensure that the device will not affect the function of the original stack when embedded; computer correction calculation is used to reduce the measurement site deviation and system errors caused by heat; and computer control signals are used to control the closing of switches to realize simultaneous measurement of multi-partition and multi-physical quantities of large-area fuel cells under limited data acquisition channels.

[0047] The present invention can measure the reaction state of any single cell in the stack by staggered distribution of current channels and conductive metals in combination with the water flow field, breaking through the position limitation that the existing test device can only be placed at the end cell of the stack; at the same time, the flow field structure and test data of the test device are corrected to obtain the membrane electrode reaction state, thereby improving the accuracy of the test results. The fuel cell multi-physical field online test device proposed by the present invention has high integration, flexible test sites, little impact on the stack, and simple operation.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The present invention adopts a battery current conduction path design combined with a flow field, which can replace the bipolar plate and be installed at any battery cell to perform online measurement of the multi-physical field distribution of the fuel cell stack, making the test flexible. At the same time, the influence of the embedded measurement plate on the water and gas distribution of the stack is considered, and the flow field inlet and outlet are adjusted;

[0050] (2) The present invention adopts a multi-channel signal acquisition method in which a computer controls the signal control switch to adjust the changes in the collected signal, which can meet the needs of multi-partition and multi-physical field signal acquisition when the signal acquisition equipment has fewer channels; at the same time, through computer calculation and analysis, the current density measurement error caused by resistor heating and the temperature measurement error caused by the sensor site are corrected, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1It is a schematic diagram of the three-dimensional structure of a fuel cell multi-physical field online testing device in an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the main structure of the electrical impedance measurement board in an embodiment of the present invention;

[0053] Figure 3 A schematic diagram of the structural modification of the flow field inlet and outlet in an embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the main structure of the partition in an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of the main structure of the temperature and humidity measurement board in an embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the main structure of a monopolar plate in an embodiment of the present invention;

[0057] Figure 7 It is a schematic diagram of the three-dimensional structure of a single partition of a fuel cell multi-physical field online testing device in an embodiment of the present invention;

[0058] Figure 8 It is a schematic cross-sectional structure diagram of a fuel cell multi-physical field online testing device in an embodiment of the present invention;

[0059] Fig. 9 It is a connection diagram of a fuel cell multi-physical field online testing device in the case of measuring a battery in the middle of a fuel cell stack according to an embodiment of the present invention;

[0060] Fig.10 It is a connection diagram of a fuel cell multi-physical field online testing device in the case of stack end battery measurement in an embodiment of the present invention;

[0061] Fig.11 Graph showing the temperature distribution of the resistor during measurement in an embodiment of the present invention.

[0062] Description of the markings in the figure:

[0063] 1—electrical impedance measurement board, 2—partition, 3—temperature and humidity measurement board, 4—monopolar plate, 5—signal control switch, 6—data acquisition module, 7—computer, 8—load, 9—excitation generator, 10—membrane electrode;

[0064] 11—cathode gas flow field, 12-1—first conductive metal, 12-2—second conductive metal, 12-3—third conductive metal, 12-4—fourth conductive metal, 13—sealing groove, 14—resistor, 15-1—first current channel, 15-2—second current channel, 15-3—third current channel, 16—signal channel, 17—air hole, 18—mounting hole, 19—temperature and humidity sensor, 20—cooling water flow field, 21—anode gas flow field;

[0065] 22—bipolar plate, 23—current collecting plate. DETAILED DESCRIPTION

[0066] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0067] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which 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 operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are used to describe common objects, which only refer to different instances of the same object, and are not intended to imply that the objects described in this way must adopt a given order, whether in time, space, order or any other way.

[0068] In the description of the present invention, it should be noted 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, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] Example:

[0070] A fuel cell multi-physics field online testing device, such as Figure 1 As shown, the main body includes a dielectric impedance measurement plate 1, a partition plate 2 and a temperature and humidity measurement plate 3 which are stacked in sequence.

[0071] The electric impedance measurement board 1 and the temperature and humidity measurement board 3 are provided with a water flow field, the electric impedance measurement board 1 is provided with an array of resistors 14, and the temperature and humidity measurement board 3 is provided with an array of temperature and humidity sensors 19.

[0072] The main body can be placed at the end battery or any battery in the middle of the battery stack to measure multiple physical fields such as current density, temperature, humidity, impedance, etc. inside the flow channel or at the membrane electrode;

[0073] like Figure 2 , Figure 7 and Figure 8 As shown, the electrical impedance measurement board 1 is divided into multiple partitions of an array in the board surface direction and three layers with different functions in the board thickness direction.

[0074] A cathode gas flow field 11 is disposed on the upper side of the upper surface layer, and first conductive metals 12-1 insulated from each other are disposed on the flow channel ridges of the cathode gas flow field 11.

[0075] The upper side of the middle layer is provided with an array resistor 14 and a channel connecting the two ends of the resistor 14.

[0076] A second conductive metal 12-2 is disposed on the lower side of the lower surface layer;

[0077] A first current channel 15-1 is provided between the first conductive metal 12-1 of the flow channel ridge of the cathode gas flow field 11 on the upper surface layer and the lower surface layer in a single partition of the electrical impedance measurement plate 1, and the second conductive metal 12-2 is not provided at the connection between the lower surface layer and the first current channel 15-1 for insulation.

[0078] A second current channel 15-2 is provided between the flow channel groove of the cathode gas flow field 11 on the upper surface layer in the single partition and the second conductive metal 12-2 on the lower surface layer.

[0079] The first current channel 15-1 and the second current channel 15-2 are arranged alternately and one end is insulated from the conductive metal, and the resistor 14 is connected to the first current channel 15-1 and the second current channel 15-2, so that the current passes through the first conductive metal 12-1, the first current channel 15-1, the resistor 14, the second current channel 15-2 and the second conductive metal 12-2 in sequence;

[0080] Each layer in each partition of the electrical impedance measurement board 1 is provided with air holes 17 corresponding to the temperature and humidity sensors 19. The corresponding position of the air holes 17 is located in the flow channel groove of the cathode gas flow field 11.

[0081] A sealing groove 13 is provided on the periphery, and a sealing strip is filled in the sealing groove 13 to seal and connect with the adjacent plates;

[0082] In this embodiment, the resistor 14, the first current channel 15-1, the second current channel 15-2 and the air hole 17 of the electrical impedance measurement board 1 in a single partition are all provided at one place;

[0083] like Figure 4 , Figure 7 and Figure 8 As shown, the partition 2 is divided into multiple partitions in an array in the direction of the plate surface, which are conductive, and each partition is provided with a mounting hole 18 corresponding to the temperature and humidity sensor 19. The size of the mounting hole 18 is larger than that of the temperature and humidity sensor 19.

[0084] A sealing groove 13 is provided on the periphery, and a sealing strip is filled in the sealing groove 13 to seal and connect with the adjacent plates;

[0085] In this embodiment, the mounting hole 18 of the partition 2 in the single partition is provided at one location;

[0086] like Figure 5 , Figure 7 and Figure 8 As shown, the temperature and humidity measuring plate 3 is divided into multiple partitions of an array in the plate surface direction, and is divided into three layers with different functions in the plate thickness direction.

[0087] The upper side of the upper surface layer is provided with an array of temperature and humidity sensors 19 and a third conductive metal 12-3.

[0088] A channel is provided on the upper side of the middle layer to connect the two ends of the temperature and humidity sensor 19.

[0089] A cooling water flow field 20 is provided on the lower side of the lower surface layer, and fourth conductive metals 12 - 4 insulated from each other are provided on the flow channel ridges of the cooling water flow field 20 ;

[0090] A signal channel 16 is provided between the flow channel grooves of the cooling water flow field 20 of the upper surface layer and the lower surface layer in the single partition of the temperature and humidity measurement plate 3, and the connection between the upper surface layer and the signal channel 16 is not provided with the third conductive metal 12-3 for insulation.

[0091] A third current channel 15-3 is provided between the third conductive metal 12-3 of the upper surface layer in the single partition and the fourth conductive metal 12-4 of the flow channel ridge of the cooling water flow field 20 of the lower surface layer.

[0092] The signal channel 16 and the third current channel 15-3 are arranged in isolation, and both ends of the signal channel 16 are insulated from the conductive metal and connected to the temperature and humidity sensor 19, so that the temperature and humidity sensor 19 transmits the measurement signal to the middle layer output through the surrounding signal channel 16, and the current is transmitted between the third conductive metal 12-3 and the fourth conductive metal 12-4 through the third current channel 15-3;

[0093] In this embodiment, the temperature and humidity sensor 19 of the temperature and humidity measurement board 3 in a single partition is provided at one location, and the signal channel 16 and the third current channel 15-3 are provided at two locations;

[0094] like Figures 8 to 10As shown, when the device is used for the middle battery of the battery stack, the electric impedance measurement plate 1, the separator 2, the temperature and humidity measurement plate 3 and the monopolar plate 4 stacked in sequence constitute the main body, and the main body is placed between a pair of membrane electrodes 10 instead of the bipolar plate 22, and the bipolar plate 22 is placed on the other side of the membrane electrode 10;

[0095] When the device is used for the end battery of the battery stack, the electric density impedance measurement plate 1, the separator 2 and the temperature and humidity measurement plate 3 stacked in sequence constitute a main body, and the main body is placed between the membrane electrode 10 and the current collecting plate 23 instead of the bipolar plate 22, and the bipolar plate 22 is placed on the other side of the membrane electrode 10;

[0096] like Figures 6 to 8 As shown, the monopolar plate 4 is conductive, and a cooling water flow field 20 and an anode gas flow field 21 are provided on both sides.

[0097] A sealing groove 13 is provided on the periphery, and a sealing strip is filled in the sealing groove 13 to seal and connect with the adjacent plates;

[0098] The current density measuring board 1 and the temperature and humidity measuring board 3 are made of multilayer PCB boards, the conductive metal is made of surface copper, the resistor 14 is made of thick copper wire, the temperature and humidity sensor 19 is made of SHT31-ARP-B sensor produced by SENSIRION, the current channel and the signal channel 16 are made of through holes, the separator 2 and the monopolar plate 4 are made of graphite plates or metal plates with good conductivity through machining, and in this embodiment, graphite plates are preferably used;

[0099] The types of sensors installed are not limited to temperature and humidity sensors. Oxygen concentration sensors, endoscopes, or other sensors targeting the multi-physics field of fuel cells can also be placed.

[0100] When the device is used for the battery in the middle of the battery stack, the battery current will flow through the membrane electrode 10, the first conductive metal 12-1 on the upper surface of the electric impedance measurement plate 1, the first current channel 15-1, the resistor 14, the second current channel 15-2, the second conductive metal 12-2 on the lower surface, the partition 2, the third conductive metal 12-3 on the upper surface of the temperature and humidity measurement plate 3, the third current channel 15-3, the fourth conductive metal 12-4 on the lower surface, the monopolar plate 4, and then reach the next membrane electrode 10;

[0101] When the device is used for the end battery of the battery stack, the battery current will flow through the membrane electrode 10, the first conductive metal 12-1 on the upper surface of the electric impedance measurement plate 1, the first current channel 15-1, the resistor 14, the second current channel 15-2, the second conductive metal 12-2 on the lower surface, the partition 2, the third conductive metal 12-3 on the upper surface of the temperature and humidity measurement plate 3, the third current channel 15-3, and the fourth conductive metal 12-4 on the lower surface, and then directly enter the current collecting plate 23;

[0102] The device contains a water flow field to ensure the normal water supply to the battery;

[0103] The main body is provided with a cathode gas flow field 11, a cooling water flow field 20, an anode gas flow field 21, and a current conduction path combined with the flow field. While implementing multi-physical field measurements, the operation requirements of current conduction and water and gas supply inside the battery stack are met, ensuring that the device can measure any battery inside or at the end of the battery stack.

[0104] The inlet and outlet structures of the water flow field are different from those of the ordinary plate flow field. The introduction of the device will change the distribution of water vapor in the battery. The device selects the inlet form, including the step structure or the distribution area flow channel, according to the change of the water flow field on the measuring plate compared with the normal plate flow resistance, and adjusts the geometric dimensions of the step inlet or the distribution area to reduce the impact of the device on the water flow field and the distribution of the two-electrode gas and cooling water, and avoid the problem of uneven water vapor distribution caused by the embedding of the main body;

[0105] In this embodiment, if Figure 3 As shown, due to the draft angle of the actual bipolar plate 22 flow field, the flow resistance of the bipolar plate 22 flow field is smaller than that of the measuring plate flow field. In order to compensate for the influence of the larger flow resistance of the measuring plate, the inlet and outlet structures of the cathode gas flow field 11, the cooling water flow field 20 and the anode gas flow field 21 cancel the step structure and adopt a planar rectangular distribution area flow channel to reduce the change of the stack flow resistance caused by the device and the influence on the distribution of the cathode gas, cooling water and anode gas inside the battery;

[0106] like Fig. 9 and Fig.10 As shown, the device also includes peripheral equipment such as a data acquisition module 6, a computer 7, a load 8 and an excitation generator 9. The measurement signals of the electrical impedance measurement board 1 and the temperature and humidity measurement board 3 are imported into the data acquisition module 6, and finally uploaded to the computer 7, and the load 8 and the excitation generator 9 are connected to the two ends of the battery stack. The computer 7 processes the measurement signal, controls the state of the load 8, and controls the disturbance input of the excitation generator 9. The peripheral equipment can correct the multi-physical field test signal obtained by the main body, so as to obtain the real distribution of the multi-physical field in the membrane electrode 10 area. The dotted line in the figure represents the signal line, and the solid line represents the wire;

[0107] The data acquisition module 6 respectively collects the voltage drop across the resistor 14 in each partition of the electric impedance measurement board 1, and the temperature and humidity of the reaction gas passing through the air hole 17 of the electric impedance measurement board 1 and the mounting hole 18 of the partition 2 detected by the temperature and humidity sensor 19 in each partition of the temperature and humidity measurement board 3, and uploads the voltage drop and temperature and humidity to the computer 7 for correction and image processing to obtain the current density, temperature, and humidity distribution;

[0108] The data acquisition module 6 acquires the voltage response between the first current channel 15-1 in each partition and the anode of the bipolar plate 22 on the other side of the membrane electrode 10 on the upper side of the electrical impedance measurement plate 1 when the excitation generator 9 inputs a disturbance, and transmits the voltage response to the computer 7 for processing to obtain the distribution of the partition impedance;

[0109] The computer 7 automatically adjusts the working state of the load 8 according to the measured physical field distribution;

[0110] The data acquisition module 6 uses a PXIe series data acquisition card chassis produced by NI, and the load 8 uses a conventional electronic load produced by ITECH;

[0111] The device also includes a peripheral device of a signal control switch 5, which is arranged between the main body and the data acquisition module 6, and is controlled by a computer 7. The measurement signals of the electrical impedance measurement board 1 and the temperature and humidity measurement board 3 are introduced into the data acquisition module 6 through the signal control switch 5. The computer 7 controls the opening and closing of the signal control switch 5. The peripheral device can realize the partitioning of different areas of the flow field or the sequential data collection of different physical fields, and realize the rapid measurement of large-area multi-physical fields;

[0112] The signal measured by the main body is collected by the data acquisition module 6 after passing through the signal control switch 5 and uploaded to the computer 7. After calculation, correction and visualization, it is presented to the user. At the same time, the computer 7 appropriately adjusts the load 8 of the battery stack according to the measurement results to adapt to the current working condition of the battery stack;

[0113] The computer 7 calculates the partition current density according to the voltage drop uploaded by the data acquisition module 6, calculates the partition impedance according to the response signal, and corrects the temperature and humidity measurement results of the test site to the temperature and humidity at the membrane electrode 10, and finally presents the test results to the user in a graphical form.

[0114] A fuel cell multi-physics field online testing method is provided, and the fuel cell multi-physics field online testing device is used for testing. The specific steps are as follows:

[0115] The computer 7 corrects the current density signal of the resistor 14 and the temperature signal of the temperature and humidity sensor 19 under the measured high temperature, respectively, to reduce the influence of the heating of the resistor 14 on the current density measurement and the influence of the installation position of the temperature and humidity sensor 19 on the temperature measurement, and obtains the current density and temperature distribution of the reaction area of ​​the membrane electrode 10. The correction relationship comes from experimental calibration and analytical model calculation;

[0116] Current density test: Due to the thermal effect of the resistor 14, the actual temperature of the resistor 14 is higher than the reaction temperature inside the fuel cell during measurement. The computer 7 obtains the corresponding relationship between the current density flowing through the resistor 14 and the actual temperature of the resistor 14 under the conditions of the specific battery reaction temperature and cooling water temperature through finite element calculation, and further obtains the corresponding relationship between the voltage drop across the resistor 14 and the actual resistance value of the resistor 14, thereby calculating the current density of the resistor 14 in each partition.

[0117] Temperature test: Due to the distance between the installation position of the temperature and humidity sensor 19 and the membrane electrode 10, there is a difference between the temperature of the gas reaching the measurement position and the temperature of the membrane electrode 10; the computer 7 obtains the relationship between the temperature t0 of the battery membrane electrode 10, the temperature t1 measured by the temperature and humidity sensor 19, and the cooling water temperature t2 through finite element calculation, and calculates the temperature t0 of the membrane electrode 10 in each partition according to the temperature t1 measured by the temperature and humidity sensor 19 and the cooling water temperature t2;

[0118] In this embodiment, the resistor 14 is a copper wire with a length of 3 mm and a width of 0.5 mm, and a 0.5 mm copper wire is connected at both ends to conduct electricity. When the membrane electrode 10 temperature is 95°C, the cooling water temperature is 80°C, and the current density is CD = 2A / cm 2 Under the condition of Fig.11 As shown, the computer 7 obtains the temperature of the resistor 14 under different current densities through finite element calculation, and the relationship between the copper resistance and the temperature follows R=ρ0[1-α(T-T0)]L / A, ρ0 is the conductivity of copper at the reference temperature T0, T is the current temperature, α is the temperature coefficient of copper, L is the length of the resistor 14, and A is the cross-sectional area of ​​the resistor 14. Based on this, the relationship between the current density CD and the resistance value R of the resistor 14 is obtained as CD=φ(R), and the voltage drop of the resistor 14 is V=R×CD×S, where S is the partition area. Combined, the relationship between the current density CD and the voltage drop V across the resistor 14 is CD=Φ(V). Under the conditions of 95°C for the membrane electrode 10 temperature and 80°C for the cooling water temperature in each partition, the corresponding relationship between the current density CD and the voltage drop V of the resistor 14 is CD=-5E-07V 3 -0.0001V 2 +0.0611V-0.0013;

[0119] In this embodiment, according to Newton's cooling law, q=h×(T f -T s ) and the one-dimensional steady-state heat conduction equation T(x) = T s +q×x / k, h is the convective heat transfer coefficient, k is the thermal conductivity, T f is the fluid temperature, which is related to the membrane electrode 10 temperature t0, T sis the solid surface temperature, which is related to the cooling water temperature t2, and x is the conduction distance, which is related to the distance from the membrane electrode 10 to the temperature and humidity sensor 19. It can be seen that there is a linear relationship between the membrane electrode 10 temperature t0, the temperature t1 measured by the temperature and humidity sensor 19, and the cooling water temperature t2. The gas flow rate in a single flow channel is 7×10 -6 kg / s, the computer 7 obtains the linear relationship between the three temperatures under different gas flow rates through finite element calculation as t0-t2=0.3851(t1-t2)+0.0651, and the temperature t0 of the membrane electrode 10 at the reaction site in each partition can be obtained according to the temperature t1 and the cooling water temperature t2 measured by the temperature and humidity sensor 19;

[0120] Partition impedance test, by applying sinusoidal micro-interference to each test partition of the fuel cell through the excitation generator 9, the data acquisition module 6 collects the frequency response signal of each partition in real time, and the computer 7 calculates the AC impedance of each partition according to the response signal;

[0121] When the number of acquisition channels is insufficient, the four measurement signals in each partition can share one acquisition channel. The user can control the opening and closing of the signal control switch 5 of various physical quantities through the computer 7 according to the needs to achieve the measurement of a certain physical quantity; the opening and closing sequence and alternating frequency of the signal control switch 5 can also be adjusted through the computer 7 to achieve the sequential measurement of multiple physical fields in different areas of the flow field, and finally complete the entire flow field test, while adjusting the refresh frequency of the distribution image;

[0122] When the measured physical quantity signal is less than the number of channels of the data acquisition module 6, all signal control switches 5 are closed; when the measured physical quantity signal is more than the number of channels of the data acquisition module 6, one acquisition channel is connected to multiple measurement signals, and the user can control the opening and closing of the signal control switch 5 through the computer 7 to realize the acquisition and measurement of specific physical quantity signals in a specific partition, and can also realize the simultaneous measurement of all multi-physical fields of the battery stack by adjusting the signal control switch 5 to open and close in a cycle;

[0123] The number of channels of the data acquisition module 6 is m, and the number of partitions is n; when m>=4n, all signal control switches 5 are closed, and the device simultaneously tests the current density, temperature, humidity, and impedance distribution of all partitions of the battery stack; when m<4n, one acquisition channel is connected to multiple measurement signals, and the user can freely adjust the closure of the signal control switch 5 through the computer 7 to control the number of partitions and the type of physical quantities collected by the data acquisition module 6, and can also control the update order and refresh frequency of the multi-physical field visualization window by adjusting the opening and closing sequence and switching frequency of the signal control switch 5.

[0124] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A fuel cell multi-physical field online testing device, characterized in that: The device comprises a main body of an electric impedance measurement plate (1), a partition (2) and a multi-physical field measurement plate which are stacked in sequence, the electric impedance measurement plate (1) and the multi-physical field measurement plate are provided with a water flow field, the electric impedance measurement plate (1) is provided with an array of resistors (14), the multi-physical field measurement plate is provided with an array of sensors, and the main body is placed on a battery at the end of a battery stack or any battery in the middle; The electrical impedance measurement plate (1) is provided with multiple partitions of an array in the plate surface direction and three layers with different functions in the plate thickness direction, wherein a cathode gas flow field (11) is provided on the upper surface layer, a first conductive metal (12-1) insulated from each other is provided on the flow channel ridge of the cathode gas flow field (11), an array of resistors (14) and channels connecting the two ends of the resistors (14) are provided on the middle layer, and a second conductive metal (12-2) is provided on the lower surface layer; A first current channel (15-1) is provided between a first conductive metal (12-1) of a flow channel ridge of a cathode gas flow field (11) on an upper surface layer in a single partition and a lower surface layer, a second conductive metal (12-2) is not provided at a connection between the lower surface layer and the first current channel (15-1) for insulation, a second current channel (15-2) is provided between a flow channel groove of the cathode gas flow field (11) on an upper surface layer in a single partition and a second conductive metal (12-2) on a lower surface layer, the first current channel (15-1) and the second current channel (15-2) are arranged in an alternating manner and one end is insulated from the conductive metal, and the resistor (14) is connected to the first current channel (15-1) and the second current channel (15-2).

2. A fuel cell multi-physical field online testing device according to claim 1, characterized in that: Each layer in each partition of the electrical impedance measurement plate (1) is provided with an air hole (17) corresponding to the sensor, and the corresponding position of the air hole (17) is located in the flow channel groove of the cathode gas flow field (11); The partition (2) is divided into multiple partitions in an array in the direction of the plate surface, and is conductive. A mounting hole (18) corresponding to the sensor is opened in each partition, and the size of the mounting hole (18) is larger than that of the sensor.

3. A fuel cell multi-physical field online testing device according to claim 1, characterized in that: The multi-physics field measurement board is provided with multiple partitions of an array in the board surface direction and three layers with different functions in the board thickness direction, wherein an array of sensors and a third conductive metal (12-3) are provided on the upper surface layer, a channel connecting two ends of the sensor is provided on the middle layer, a cooling water flow field (20) is provided on the lower surface layer, and a fourth conductive metal (12-4) insulated from each other is provided on the flow channel ridge of the cooling water flow field (20).

4. A fuel cell multi-physical field online testing device according to claim 3, characterized in that: A signal channel (16) is provided between the flow channel grooves of the cooling water flow field (20) of the upper surface layer and the lower surface layer in a single partition of the multi-physical field measurement plate; a third conductive metal (12-3) is not provided at the connection between the upper surface layer and the signal channel (16) for insulation; a third current channel (15-3) is provided between the third conductive metal (12-3) of the upper surface layer in the single partition and the fourth conductive metal (12-4) of the flow channel ridge of the cooling water flow field (20) of the lower surface layer; the signal channel (16) and the third current channel (15-3) are arranged in isolation; and both ends of the signal channel (16) are insulated from the conductive metal and connected to the sensor.

5. The fuel cell multi-physical field online testing device according to claim 1, characterized in that: When the device is used in a battery in the middle of a stack, a main body is formed by sequentially stacking an electric impedance measurement plate (1), a separator (2), a multi-physical field measurement plate and a monopolar plate (4), and the main body is placed between a pair of membrane electrodes (10) instead of a bipolar plate (22). The bipolar plate (22) is placed on the other side of the main body of the membrane electrode (10); When the device is used for a battery at the end of a stack, a main body is formed by sequentially stacking an electric impedance measurement plate (1), a separator (2) and a multi-physical field measurement plate. The main body replaces a bipolar plate (22) and is placed between a membrane electrode (10) and a current collecting plate (23). The membrane electrode (10) is provided with a bipolar plate (22) on the other side of the main body.

6. A fuel cell multi-physical field online testing device according to claim 5, characterized in that: The monopolar plate (4) is conductive, and a cooling water flow field (20) and an anode gas flow field (21) are respectively provided on both sides.

7. A fuel cell multi-physical field online testing device according to claim 1, characterized in that: The inlet and outlet structures of the water flow field include a step structure or a distribution area flow channel.

8. The fuel cell multi-physical field online testing device according to claim 1, characterized in that: The device also includes peripheral equipment including a data acquisition module (6), a computer (7), a load (8) and an excitation generator (9); the measurement signals of the electric impedance measurement board (1) and the multi-physical field measurement board are imported into the data acquisition module (6) and finally uploaded to the computer (7); the load (8) and the excitation generator (9) are connected to two ends of the battery stack; the computer (7) processes the measurement signal, controls the state of the load (8), and controls the disturbance input of the excitation generator (9); The device also includes a peripheral device of a signal control switch (5), wherein the signal control switch (5) is arranged between the main body and the data acquisition module (6), and is controlled by a computer (7). The measurement signals of the electrical impedance measurement board (1) and the multi-physical field measurement board are introduced into the data acquisition module (6) through the signal control switch (5), and the computer (7) controls the opening and closing of the signal control switch (5).

9. A fuel cell multi-physical field online testing method, characterized in that: The method uses a fuel cell multi-physical field online testing device as claimed in any one of claims 1 to 8 for testing, and the method comprises the following steps: The computer (7) corrects the current density signal of the resistor (14) and the temperature signal of the sensor at the measured high temperature respectively, so as to reduce the influence of the heating of the resistor (14) on the current density measurement and the influence of the sensor installation position on the temperature measurement, and obtains the current density and temperature distribution of the reaction area of ​​the membrane electrode (10), wherein the correction relationship is obtained from experimental calibration and analytical model calculation; Current density test: the computer (7) obtains the corresponding relationship between the current density flowing through the resistor (14) and the actual temperature of the resistor (14) under the conditions of specific battery reaction temperature and cooling water temperature through finite element calculation, and further obtains the corresponding relationship between the voltage drop across the resistor (14) and the actual resistance value of the resistor (14), thereby calculating the current density of the resistor (14) in each partition; Temperature test: the computer (7) obtains the relationship between the temperature t0 of the battery membrane electrode (10), the temperature t1 measured by the temperature and humidity sensor (19), and the cooling water temperature t2 through finite element calculation, and calculates the temperature t0 of the membrane electrode (10) in each partition according to the temperature t1 measured by the temperature and humidity sensor (19) and the cooling water temperature t2; Partition impedance testing, by applying sinusoidal micro-interference to each test partition of the fuel cell through an excitation generator (9), a data acquisition module (6) collects frequency response signals of each partition in real time, and a computer (7) calculates the AC impedance of each partition based on the response signals.

10. A fuel cell multi-physical field online testing method according to claim 9, characterized in that: When the number of acquisition channels is insufficient, the measurement signals in each partition share one acquisition channel, and the user controls the opening and closing of the signal control switches (5) of various physical quantities through a computer (7) according to the needs, so as to achieve the measurement of a certain physical quantity; or, the computer (7) adjusts the opening and closing sequence and the alternating frequency of the signal control switches (5) to achieve the sequential measurement of multiple physical fields in different areas of the flow field, and finally completes the entire flow field test, while adjusting the refresh frequency of the distribution image.

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