CN112229537B

CN112229537B - Subarea test system for detecting current and temperature distribution of fuel cell

Info

Publication number: CN112229537B
Application number: CN202010982103.8A
Authority: CN
Inventors: 曹继申; 陈锦华; 殷聪; 李凯; 汤浩
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2020-09-17
Filing date: 2020-09-17
Publication date: 2021-12-03
Anticipated expiration: 2040-09-17
Also published as: CN112229537A

Abstract

The invention discloses a partition test system for detecting the current and temperature distribution of a fuel cell, belonging to the field of fuel cell testing, in particular to the field of testing the current and temperature distribution of a fuel cell stack. The acquisition board of the present invention adopts an equal impedance wiring method to make the impedance between each partition and the sampling resistor as consistent as possible; the sampling resistance is arranged outside the acquisition board, no buried resistance process is required, the cost is low and the implementation is simple; the temperature sensitive resistor is placed on the printed circuit board Instead of being buried in the flow channel, the damage of the temperature measuring element to the fuel cell structure is eliminated, and the reaction in the battery is not affected; online high-density matrix partition current and temperature distribution measurement can be realized, and the data can be visualized in real time. Display the current distribution and temperature characteristics of the partitions; the invention can be used in high-speed acquisition scenarios, and is of great significance for studying the dynamic characteristics of fuel cells.

Description

Subarea test system for detecting current and temperature distribution of fuel cell

Technical Field

The invention belongs to the field of fuel cell testing, in particular to the field of testing the current and temperature distribution of a fuel cell stack.

Background

With the increasing concern of people on environmental problems, novel environment-friendly energy sources gradually enter the research field of people. As a new energy device with high efficiency and cleanness, the fuel cell has been gradually applied to the fields of aerospace, ships, automobiles, standby power supplies and the like. Among them, the pem fuel cell is considered to be an important development direction of new energy in the future due to its characteristics of high energy conversion efficiency, low working temperature, short starting time, high power density, etc. Pem fuel cell life and performance are affected by many factors, which are directly reflected in the current distribution and temperature distribution within the cell. The uneven distribution of current in the active reaction region can generate internal voltage difference and in-plane current, which leads to the reduction of the utilization rate of reactants and electrocatalysts, the reduction of the battery efficiency and the acceleration of battery aging, and finally leads to the reduction of the service life of the battery. The current distribution is an important parameter for characterizing the distribution of reactants in the fuel cell, the state of the cell, and the like. Temperature has a significant effect on fuel cell performance during cell operation. The performance of the fuel cell is sensitive to temperature, and because the fuel cell has a compact structure, the internal temperature field is unevenly distributed, which easily affects the proceeding of the electrochemical reaction, and the unsuitable temperature will cause the performance of the cell to be reduced. The real-time temperature detection can explore the relation between current distribution and temperature distribution, provide basis for the control of the fuel system battery and ensure the normal and efficient work of the system.

Therefore, a partition detection system capable of acquiring the current and temperature distribution inside the fuel cell needs to be designed, and the partition detection system has important significance in the aspects of researching the current and temperature distribution inside the fuel cell, improving the performance of the stack, optimizing the design and structure of the stack and the like.

At present, the partition detection technology is classified according to a test mechanism, and there are three types: resistance network technology, electromagnetic induction testing technology, and printed circuit board technology. The resistance network technology and the electromagnetic induction testing technology are difficult to realize, the technology is complex, the battery structure can be damaged, and the application is less. The printed circuit board has low technical cost and simple realization, and is widely used. The sampling resistor can be divided into a buried resistor type and an external resistor type according to the placement mode of the sampling resistor. The embedded resistance type is that a resistance medium is embedded into a partition test board, and a signal wire is led out to an external signal acquisition device, so that a cathode plate of the fuel cell is replaced by the partition test board to obtain current distribution during testing. However, the current buried resistor technology has high process cost and is immature in China, so that the resistor precision of the buried resistor technology cannot be controlled, extra resistor calibration is needed, and the test difficulty is increased. The external resistor is characterized in that the sampling resistor is placed on the outer side of the circuit board, and the test subarea and the sampling resistor are connected through copper foil. Although the structure is simple, due to design and process limitations, impedance differences between the sub-partitions are caused, and current distribution and measurement are seriously influenced.

For temperature measurement, the conventional methods embed elements such as a micro temperature sensor, a thermocouple, a thermal resistor and the like in a flow channel of a fuel cell or thermally press the elements with a membrane electrode of the fuel cell, which are difficult in process, and the elements damage the overall structure of the cell along with the implantation of the elements, possibly resulting in the reduction of the air tightness of the cell, the reduction of the active area of the membrane electrode and further the influence on the performance of the fuel cell.

In order to visually represent the chemical reaction condition inside the fuel cell, real-time imaging processing needs to be performed on data of each partition. It is now common practice to process the acquired data directly on the same computer and then generate an image. However, real-time data processing and image generation need to consume a large amount of computer memory and processor resources, and particularly when a high-density partition scene is faced, such an approach may cause the computer to be stuck, and in a severe case, an upper computer is crashed, and a system is uncontrollable, and an accident occurs.

Disclosure of Invention

Aiming at the problems of higher process cost and immature technology of the existing buried resistor technology, the invention improves and designs the acquisition plate for detecting the current and temperature distribution of the fuel cell, which has a simple structure and mature process.

The invention detects the temperature and the current of different subareas of the fuel cell stack, and then respectively carries out data acquisition on the current and the temperature of each subarea for subsequent data acquisition processing. Therefore, the technical scheme of the invention is as follows: a zoned test system that detects fuel cell current and temperature profiles, the zoned test system comprising: the fuel cell detection device comprises a collecting plate, a signal amplifying module, a data collecting module, a data processing module and a data display module, wherein the collecting plate is arranged inside a fuel cell to be detected, collects temperature and current information inside the fuel cell and transmits the temperature and current information to the signal amplifying module; the collecting board is a printed circuit board with a multilayer structure, and the printed circuit board consists of an electric pile internal part and an electric pile external part; copper-clad gold-plated partitions are arranged on the upper surface array of the inner part of the electric pile, each copper-clad gold-plated partition is of a concave sheet structure and is attached to the upper surface of the printed circuit board; a metallized through hole is arranged at the position of each copper-clad and gold-plated partition and penetrates through the multilayer structure of the whole printed circuit board; dividing all the copper-clad gold-plating subareas into a plurality of parts, wherein each part corresponds to an interlayer in the multilayer printed circuit board, each copper-clad gold-plating subarea is connected to the interlayer in the corresponding multilayer printed circuit board through a respective metalized through hole, and each copper-clad gold-plating subarea is correspondingly provided with an equal-impedance wiring in the interlayer; the output ends of all the equal-impedance wiring lines are arranged at the outer part of the pile of the printed circuit board; every equal impedance wiring of galvanic pile outside part of printed circuit board all corresponds and is provided with 4 metallized through-holes, is respectively: the first sampling resistor metalized through hole, the second sampling resistor metalized through hole, the first signal wiring terminal metalized through hole and the second signal wiring terminal metalized through hole penetrate through the whole multilayer printed circuit board; the output end of each interlayer equal-impedance wiring is connected with a first sampling resistance metalized through hole in the interlayer, the first sampling resistance metalized through hole is connected with a second signal wiring terminal metalized through hole through a microstrip line, and the second sampling resistance metalized through hole is connected with the first signal wiring terminal metalized through hole; the upper surface of the part, located outside the pile, of the printed circuit board is provided with a plurality of sampling resistors and a plurality of signal wiring terminals, each equal-impedance wiring corresponds to one sampling resistor and one signal wiring terminal, one end of each sampling resistor is connected with a corresponding first sampling resistor metalized through hole, and the other end of each sampling resistor is connected with a corresponding second sampling resistor metalized through hole; one end of each signal connecting terminal is connected with the corresponding first signal connecting terminal metalized through hole, and the other end of each signal connecting terminal is connected with the corresponding second signal connecting terminal metalized through hole; the second sampling resistance metalized through hole is simultaneously connected with a copper-clad current collecting area which is positioned on the upper surface of the outer part of the pile of the printed circuit board;

wherein, a temperature-sensitive resistor is arranged in the concave part of each concave sheet copper-clad gold-plated partition, and all the temperature-sensitive resistors are connected in series; the input end and the output end of the whole temperature-sensitive resistor series circuit are arranged on the upper surface of the external part of the printed circuit board pile, and each temperature-sensitive resistor samples the voltage of each temperature-sensitive resistor through independent wiring; the output end of each temperature-sensitive resistor sampling voltage is also arranged on the upper surface of the outer part of the printed circuit board pile; because the current flows through the copper-clad gold-plated partition, the temperature-sensitive resistor is arranged in the groove, so that the measurement of the metal temperature-sensitive resistor is more accurate, and the response is faster;

the collecting plate is adopted to replace a cathode current collecting plate in a fuel cell stack, and one side of the collecting plate, which is provided with a copper-clad and gold-plated partition, is attached to a membrane electrode of a fuel cell, so that the current and the temperature of different partitions are detected when the fuel cell works.

Furthermore, the equal-impedance wiring arranged in the interlayer of the multilayer structure printed circuit board adopts a wiring mode with equal width and equal length.

Furthermore, two metalized through holes are arranged at the position of each copper-clad gold-plating partition, the diameter of each metalized through hole is 0.7mm, the two metalized through holes extend to the interlayer of the printed circuit board corresponding to the copper-clad gold-plating partition and then are connected with the two metalized through holes through a microstrip line, and equal-impedance wiring is led out from the middle point of the microstrip line connecting the two metalized through holes. One partition corresponds to two metallized through holes, so that current flowing through the partition can be shunted, and the current carrying capacity is improved.

Compared with the prior art, the invention has the following advantages:

1) the acquisition board adopts an equal impedance wiring mode to ensure that the impedance from each subarea to the sampling resistor is as consistent as possible;

2) the sampling resistor is arranged on the outer side of the acquisition plate, a resistance burying process is not needed, the cost is low, and the realization is simple;

3) the temperature-sensitive resistor is arranged on the printed circuit board instead of being buried in the flow channel, so that the damage of the temperature measuring element to the structure of the fuel cell is eliminated, and the reaction in the cell is not influenced;

4) the online high-density matrix type subarea current and temperature distribution measurement can be realized, the data is imaged in real time, and the subarea current distribution and temperature characteristics are visually displayed;

5) the invention can be used in high-speed acquisition scenes and has important significance for researching the dynamic characteristics of the fuel cell.

Drawings

Fig. 1 is a block diagram of a fuel cell partition testing system.

Figure 2 is a schematic diagram of a fuel cell stack assembly.

FIG. 3 is a top view of a current and temperature distribution collection plate.

FIG. 4 is a bottom view of the current and temperature distribution collecting plate.

Fig. 5 is a schematic diagram of an intermediate layer serpentine routing scheme.

Fig. 6 is a schematic diagram of different width penetration wiring schemes of the intermediate layer.

Fig. 7 is a schematic side view of the current and temperature distribution collecting plate.

FIG. 8 is a schematic diagram of a temperature sensitive resistor circuit.

FIG. 9 is a schematic diagram of a high density partitioned data imaging scheme.

Fig. 10 is a flow chart of a specific method of real-time detection of the fuel cell.

In the figure: 1. a fuel cell stack; 2. a current and temperature distribution acquisition board; 3. a signal amplification module; 4. a data acquisition module; 5. a data processing module; 6. a data display module; 7. an electronic load; 8. a local server; 9. a cathode end plate; 10. A cathode insulating plate; 11: sampling a resistor; 12. a temperature-sensitive resistor; 13. an anode current collector plate; 14. an anode insulating plate; 15. an anode end plate; 16. a plurality of series connected fuel cells; 17. a hollow-out area; 18. copper-clad and gold-plated subareas; 19. metallizing the via hole; 20. sampling a resistor; 21. coating a copper current collecting area; 22. a signal wiring terminal; 23. an equal-impedance wiring; 24. an internal routing layer; 25. a current inlet; 26. a current outlet; 27. internal conductor

Detailed Description

The present invention is directed to a fuel cell with a power of 10 kw; the impedance of the copper-clad gold-plating subarea is below 3 milliohm-5 milliohm, the size is 12 mm-8 mm, the size of the reserved rectangle is 4 mm-3 mm, and the spacing distance between adjacent copper-clad gold-plating subareas is 5 mm; the size of the temperature sensitive resistor is less than 2mm x 1.5mm, and the impedance is 10K; the printed circuit board adopting a three-layer structure comprises two interlayers, all copper-clad and gold-plated regions are divided into two parts, wherein one part of the equal-impedance wiring is arranged on the first interlayer, and the other part of the equal-impedance wiring is arranged on the other interlayer; the method adopts an equal-impedance wiring mode with equal width and equal distance, the width of the equal-impedance wiring is 0.25mm, the length of the equal-impedance wiring is 122mm, and the realized impedance is below 10 milliohm.

As shown in fig. 1, the fuel cell multifunctional partition testing system comprises a fuel cell stack 1, a current and temperature distribution acquisition board 2, a signal amplification module 3, a data acquisition module 4, a data processing module 5, an electronic load 7, and a local server 8. The fuel cell stack 1 is connected to an electronic load 7 through a power line. The current and temperature distribution collecting plate 2 is used as a cathode collector plate to be transferred into the fuel cell stack 1. The output signal is connected with the signal amplification module 3 through a lead and sent to the data acquisition module 4, then processed in the data processing module 5, and a real-time image is obtained through the data display module 6.

As shown in fig. 2, a schematic diagram of a fuel cell stack assembly is shown. The fuel cell comprises an anode end plate 15, an anode insulating plate 14, an anode current collecting plate 13, a plurality of series-connected fuel cells 16, a current and temperature distribution collecting plate 2, a cathode insulating plate 10 and a cathode end plate 9 which are sequentially assembled. Wherein, the current and temperature distribution collecting plate 2 is used as a cathode current collecting plate of the electric pile. The sampling resistor 11 is arranged on the front surface of the current and temperature distribution acquisition board 8, and the temperature sensitive resistor 12 is arranged in each partition reserved area.

Fig. 3 and 4 are schematic diagrams of the current and temperature distribution collecting plate. The top layer is a copper-clad gold-plated subarea 18 which is isolated from each other by electric appliances, a temperature-sensitive resistor 12 is arranged at the reserved position of each subarea, each subarea corresponds to a sampling resistor 20, the far ends of all the sampling resistors 20 are connected to a copper-clad current collecting area 21 for collecting current, and the sampling resistors are used as the anode of a battery to be connected with an electronic load 7 during working. The bottom layer houses signal terminals 22. The signal lines are led out from the two ends of the sampling resistor 20 to the wiring terminal 22, connected with the signal amplification module 3 and then input into the data acquisition module 5, all the temperature-sensitive resistors 12 are connected in series to the same current source, and the signals at the two ends are directly connected into the data acquisition module 5 through the signal lines.

Fig. 5 and 6 are schematic diagrams of internal layering of the current and temperature distribution collecting plate. The current and temperature distribution collecting board 2 is a multilayer printed circuit board, and the inside of the board is of a multilayer structure. The inner layer is used for wiring, so that the impedance between the copper-clad gold-plated subarea 18 and the sampling resistor 20 is kept consistent, and the equal-impedance wiring 23 is obtained, and two specific embodiments are as follows: 1) equal-length wiring, wherein the lengths of all the wires are equal in a snake-shaped wiring mode; 2) and wiring in different widths and lengths so that all the wirings satisfy R ═ rho L/A. Wherein R is the impedance value, ρ is the resistivity of the copper wire, L is the length of the copper wire, A is the cross-sectional area of the copper wire, and the cross-sectional area is only related to the width when the heights are the same. Wherein the internal current passes through the metalized via 19 on the copper-clad gold-plated partition 18, through the iso-impedance wiring 23 to the proximal end of the sampling resistor 20. The electric signals at the two ends of the sampling resistor 20 and the temperature sensitive resistor 12 are led out to the wiring terminal 22 through the internal signal line and are supplied to the amplifying module 3 and the data acquisition module 4. As shown in fig. 5 and 6, when the current wiring layer cannot be wired any more, the wiring is started to a new layer.

Fig. 7 is a schematic side view of the current and temperature distribution collecting plate. The current and temperature distribution collecting board 2 is a multilayer printed circuit board. Wherein, the top layer is a copper-clad gold-plated subarea 18 which is mutually isolated from electrical appliances, all subareas are mutually insulated, and the current can not be transversely conducted. In normal operation, the top layer is in close contact with the plurality of series-connected fuel cells 16, the current reaches the copper-clad gold-plated subarea 18, passes through the metalized via hole 19 and reaches the internal wiring layer 24, and in the internal wiring layer 24, the impedance of each lead wire reaching the near end of the sampling resistor 20 from the copper-clad gold-plated subarea 18 is consistent in an equal-impedance wiring mode, so that the equal-impedance wiring 23 is obtained. The subarea current is collected to the far end of the sampling resistor 20 after passing through the equal-impedance wiring 23 and is connected to the copper-clad collecting area 21 for collecting current. Two ends of each sampling resistor 20 and each temperature-sensitive resistor 12 are connected with a signal line, the signal lines are output to a wiring terminal 22, and the signal lines can be input into the signal amplification module 3 and the data acquisition module 4 through external wires.

Fig. 8 is a circuit diagram of a temperature sensitive resistor. When the temperature-sensitive resistor works, all the temperature-sensitive resistors 12 are connected in series and input into an external constant current source. Two ends of each temperature-sensitive resistor 12 are provided with a pair of signal wires leading out to the connecting terminal 22. The temperature calculation method comprises the steps of calculating the resistance value at the current moment according to the voltages at the two ends of the temperature-sensitive resistor, and obtaining the temperature corresponding to the current resistance value in a mode of querying a data table through a program.

The number of the copper-clad gold-plated subareas 18 is the same as that of the sampling resistors 20 and that of the temperature-sensitive resistors 12, and the positions of the copper-clad gold-plated subareas correspond to those of the sampling resistors 20 and the temperature-sensitive resistors 12 one by one.

The number of rows of the copper-clad and gold-plated subareas 18 is greater than 5, and the number of columns is greater than 5.

FIG. 9 is a schematic diagram of a high density partitioned data imaging scheme. In a high-density subarea scene, a large amount of computing resources are consumed for processing and imaging a large amount of current and voltage signals, so that an upper computer is broken down. The data collected by the data collection module 4 is sent to the local server 8 through the local area network, processed in the data processing module 5, and finally displayed by the data display module 6.

Fig. 10 is a flowchart of a specific method for real-time partition detection of a fuel cell, which includes the following specific steps:

1) assembling a fuel cell stack 1 in sequence, replacing a cathode current collecting plate with a current and temperature distribution collecting plate 2, and ensuring the air tightness and uniform assembling pressure during assembling;

2) after the fuel cell 1 is assembled, checking the air tightness, if the third step is passed, or returning to the first step;

3) connecting an electronic load 7, a signal amplification module 3, a data acquisition module 4 and a data processing module 5 to the fuel cell stack 1 to form a test system;

4) supplying hydrogen, air and water, and operating system software to ensure that the test system works normally;

5) the current and temperature distribution collecting board 2 inputs the collected voltage signals at the two ends of the sampling resistor 20 and the temperature sensitive resistor 12 to the signal amplifying module 3 and the data collecting module 4.

6) The data processing module 5 processes the signals sent by the data acquisition module 4, and the data display module 6 displays real-time current distribution and temperature, displays images and records data

And repeating the step 2) and the step 6) until the task is finished.

Claims

1. A zoned test system that detects fuel cell current and temperature profiles, the zoned test system comprising: the fuel cell detection device comprises a collecting plate, a signal amplifying module, a data collecting module, a data processing module and a data display module, wherein the collecting plate is arranged inside a fuel cell to be detected, collects temperature and current information inside the fuel cell and transmits the temperature and current information to the signal amplifying module; the collecting board is a printed circuit board with a multilayer structure, and the printed circuit board consists of an electric pile internal part and an electric pile external part; copper-clad gold-plated partitions are arranged on the upper surface array of the inner part of the electric pile, each copper-clad gold-plated partition is of a concave sheet structure and is attached to the upper surface of the printed circuit board; a metallized through hole is arranged at the position of each copper-clad and gold-plated partition and penetrates through the multilayer structure of the whole printed circuit board; dividing all the copper-clad gold-plating subareas into a plurality of parts, wherein each part corresponds to an interlayer in the multilayer printed circuit board, each copper-clad gold-plating subarea is connected to the interlayer in the corresponding multilayer printed circuit board through a respective metalized through hole, and each copper-clad gold-plating subarea is correspondingly provided with an equal-impedance wiring in the interlayer; the output ends of all the equal-impedance wiring lines are arranged at the outer part of the pile of the printed circuit board; every equal impedance wiring of galvanic pile outside part of printed circuit board all corresponds and is provided with 4 metallized through-holes, is respectively: the first sampling resistor metalized through hole, the second sampling resistor metalized through hole, the first signal wiring terminal metalized through hole and the second signal wiring terminal metalized through hole penetrate through the whole multilayer printed circuit board; the output end of each interlayer equal-impedance wiring is connected with a first sampling resistance metalized through hole in the interlayer, the first sampling resistance metalized through hole is connected with a second signal wiring terminal metalized through hole through a microstrip line, and the second sampling resistance metalized through hole is connected with the first signal wiring terminal metalized through hole; the upper surface of the part, located outside the pile, of the printed circuit board is provided with a plurality of sampling resistors and a plurality of signal wiring terminals, each equal-impedance wiring corresponds to one sampling resistor and one signal wiring terminal, one end of each sampling resistor is connected with a corresponding first sampling resistor metalized through hole, and the other end of each sampling resistor is connected with a corresponding second sampling resistor metalized through hole; one end of each signal connecting terminal is connected with the corresponding first signal connecting terminal metalized through hole, and the other end of each signal connecting terminal is connected with the corresponding second signal connecting terminal metalized through hole; the second sampling resistance metalized through hole is simultaneously connected with a copper-clad current collecting area which is positioned on the upper surface of the outer part of the pile of the printed circuit board;

wherein, a temperature-sensitive resistor is arranged in the concave part of each concave sheet copper-clad gold-plated partition, and all the temperature-sensitive resistors are connected in series; the input end and the output end of the whole temperature-sensitive resistor series circuit are arranged on the upper surface of the external part of the printed circuit board pile, and each temperature-sensitive resistor samples the voltage of each temperature-sensitive resistor through independent wiring; the output end of each temperature-sensitive resistor sampling voltage is also arranged on the upper surface of the outer part of the printed circuit board pile;

2. The zonal testing system for sensing current and temperature distribution of a fuel cell of claim 1, wherein the equal-resistance wires disposed in the sandwich of the multi-layered structure printed circuit board employ a wire pattern of equal width and equal length.

3. The zonal testing system for detecting the current and temperature distribution of a fuel cell according to claim 1, wherein two metalized through holes are provided at each copper-clad gold-plated zone, the diameter of each metalized through hole is 0.7mm, the two metalized through holes extend to the interlayer of the printed circuit board corresponding to the copper-clad gold-plated zone and then are connected with the two metalized through holes through a microstrip line, and an equal-impedance wiring is led out from the middle point of the microstrip line connecting the two metalized through holes.