Fuel cell current density zoning test device

Abstract

The utility model relates to a fuel cell current density partition test device, and belongs to the technical field of fuel cell detection. In order to solve the problems of difficult PCB buried resistance process and low test precision in the existing fuel cell current density tester, the device comprising a PCB, a data acquisition system and upper computer software is designed. The PCB is installed in the fuel cell, a flow field area of the graphite runner plate is divided into a plurality of insulation areas through subareas on the PCB, and current signals of all the subareas are collected in real time through the external sampling resistor. The impedance of each partition is kept consistent, the structure is simple, and the measurement precision is high. And the data acquisition unit is responsible for acquiring, recording, analyzing and storing test data in real time. The device has high precision, stability and reliability, and is provided with a visual software interface which is visual and easy to operate and is used for displaying a test result and recording a test process in real time; the system also has an automation function, can achieve the automatic testing process and data processing, improves the testing efficiency, and reduces the workload.

Description

Technical Field

[0001] The utility model belongs to the technical field of fuel cell detection, and in particular relates to a device for zoning test of fuel cell current density. Background Art

[0002] Fuel cell current density testers play a crucial role in the development of fuel cell technology. As an efficient and clean energy conversion technology, fuel cell technology has broad application prospects, ranging from automobiles to grid backup power. Understanding and evaluating fuel cell performance relies on accurate current density testing.

[0003] Current density is a key parameter in evaluating fuel cell performance. It refers to the current per unit area and directly affects the cell's output power and efficiency. A fuel cell current density tester is used to measure the current density of a fuel cell under various conditions to assess its performance and stability. This tester typically consists of a sensor, control system, and data acquisition system, capable of monitoring the fuel cell's output current in real time and recording the data. These test instruments must possess high precision, stability, and reliability to ensure accurate and repeatable measurement results.

[0004] In the field of fuel cell current density testers, researchers and engineers are constantly working to solve a series of technical challenges to meet the needs of fuel cell performance evaluation. These challenges include but are not limited to:

[0005] Accuracy and stability: Test instruments must have high accuracy and stability to ensure reliable measurement results. Instrument performance also needs to remain stable under varying operating conditions, such as temperature, pressure, and humidity.

[0006] Operational convenience: Fuel cell current density testers typically require complex operating procedures and parameter settings, placing high demands on the operator's technical skills. Simplifying the operating procedures and improving operational convenience are key challenges.

[0007] Data processing and analysis: Test instruments must be able to efficiently collect, process, and analyze large amounts of test data. They must also provide intuitive, easy-to-understand data analysis results to help researchers quickly evaluate battery performance.

[0008] Currently, there are two main methods for detecting current density distribution using PCB technology: one is the embedded resistor method, where the sampling resistor is embedded in the partitioned detection area of ​​the PCB circuit board and clamped inside the battery. This method is immature and costly in China, and the resistor is affected by the high temperature environment of the battery, resulting in low test accuracy. The other is the external sampling resistor method, where the sampling resistor is placed on the outside of the PCB circuit board, and the test partition and the sampling resistor are connected by copper wire. This method is simple and low-cost, the sampling resistor is not affected by battery temperature, and the test accuracy is high. However, the circuit structure of the existing method is complex, which affects battery performance and test accuracy. Utility Model Content

[0009] Aiming at the problems of fuel cell current density testers in the prior art, the utility model provides a device for fuel cell current density zoning testing.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] A device for zoning current density testing of a fuel cell, comprising a fuel cell, a data acquisition system, and host computer software; wherein:

[0012] The assembly structure of the fuel cell is in the order of anode end plate, anode current collecting plate, anode graphite flow channel plate, MEA membrane electrode, cathode graphite flow channel plate, PCB board sensor, cathode current collecting plate, and cathode end plate;

[0013] The data acquisition system is a multi-channel acquisition system that transmits the collected segmented voltage signals to the data processing software of the host computer through the USB interface. The data processing software has two-dimensional and three-dimensional visual real-time display windows and can record the changes in the current density value of each partition;

[0014] Furthermore, the PCB sensor is located between the cathode graphite flow channel plate and the current collecting plate of the fuel cell. The top layer of matrix partitioned copper foil is tightly attached to the back of the cathode graphite flow channel plate, dividing the flow field area of ​​the cathode graphite flow channel plate into several areas, and each area is insulated from each other. By detecting the current flowing through each area, real-time current density data of the fuel cell is obtained.

[0015] The PCB sensor is provided with multiple measurement and acquisition units, which are arranged from top to bottom along the thickness direction of the PCB sensor: a top current collection area, a metal through-hole running through the PCB sensor, two internal wiring layers, and a bottom copper foil layer; wherein:

[0016] The top current collection area includes a plurality of top matrix partitioned copper foils arranged in a matrix; the area outside the PCB sensor includes a plurality of chip resistors, each of which is connected to the top matrix partitioned copper foils in a one-to-one correspondence via internal copper conductors; the top matrix partitioned copper foils and the internal copper conductors are connected via metal through-holes that penetrate the PCB sensor; the metal through-holes on the end pads of the chip resistors are connected to the bottom copper foil; and the ends of each unit conductor are connected to the bottom copper foil via metal through-holes.

[0017] The top current collection area is in close contact with the back of the fuel cell cathode graphite flow channel plate. The current from the cathode graphite flow channel plate flows through the top matrix partition copper foil units in sequence, flows into the internal copper wire corresponding to each unit through the metal through-hole, then flows into the external chip resistor of each unit, and finally passes through the chip resistor and the metal through-hole at the end of the wire, and finally converges to the bottom copper foil.

[0018] The bottom copper foil fits tightly against the cathode current collecting plate inside the fuel cell, conducting the total current out.

[0019] Furthermore, the top current collecting area, internal conductors, metal vias and bottom copper foil are all made of copper; the copper thickness is uniformly 75 μm;

[0020] The top current collection area and the bottom copper foil surface are both gold-plated with a thickness of 0.05 μm, which can reduce contact resistance and is not easy to oxidize;

[0021] The top layer matrix partition copper foil units in the top layer current collection area have equal areas, are independent and insulated from each other.

[0022] Furthermore, the conductor widths of the two internal wiring layers are both designed to be 2 mm, and the lengths of the unit conductors are made equal through equal impedance wiring, which allows large currents to pass through and ensures that the impedances of the unit conductors are consistent.

[0023] Each chip resistor is fixed to the PCB sensor by welding. The chip resistor is a low-temperature drift resistor with a temperature drift coefficient of 50ppm. When the temperature changes from 25°C to 120°C, the resistance value of the resistor changes by less than 0.01%. The resistance value is 0.1Ω. The chip resistor elements used in each unit are the same.

[0024] The data acquisition system has an acquisition accuracy of 0.3mV, and the collected data is uploaded to a computer via USB communication.

[0025] A fuel cell current density zoning test method, characterized in that the method converts the current signal of each unit into a voltage signal inside a chip resistor, and the voltage signal is connected to a data acquisition system via a lead. The data acquisition system processes the voltage signal collected in real time and sends it to a host computer for algorithm processing. The algorithm converts the voltage signal into a current density distribution data value inside the fuel cell, presents a current density distribution image in real time, and saves the result data to a file;

[0026] The computer software algorithm is:

[0027]

[0028] Among them, A i is the current density value of the copper foil in the i-th matrix partition, 1≤i≤0 is the total number of copper foils in the matrix partition, V i is the voltage signal value, a i is the area of ​​the copper foil of the i-th matrix partition, and R is the resistance of the sampling resistor.

[0029] Compared with the prior art, the utility model has the following advantages:

[0030] The utility model adopts an external sampling resistor method, placing the sampling resistor in the external area of ​​the PCB sensor. Through special circuit design, the circuit and test structure are simplified, ensuring the impedance consistency of each partition, thereby reducing process difficulty and cost and improving test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a device structure for current density zoning testing of a fuel cell;

[0032] Figure 2 This is a schematic diagram of the circuit principle of the current density tester PCB board sensor;

[0033] Figure 3 This is a schematic diagram of the side cross-section of the PCB sensor of the current density tester. The PCB sensor layers from top to bottom are: top layer, first layer internal routing, second layer internal routing, bottom layer;

[0034] Figure 4 This is a three-dimensional graph of the test data of the current density test system. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Figure 1 The following is a schematic diagram of the structure of a device for current density partitioning test of a fuel cell proposed by the present invention. Figure 1As shown, the fuel cell current density distribution acquisition device consists of a fuel cell, a data acquisition system, and host computer software. The fuel cell assembly structure includes an anode end plate, an anode current collector plate, an anode graphite flow plate, an MEA membrane electrode assembly (MEA), a cathode graphite flow plate, a PCB sensor, a cathode current collector plate, and a cathode end plate. The PCB sensor is located between the cathode graphite flow plate and the cathode current collector plate of the fuel cell. The matrix-partitioned copper foil on the top layer of the PCB sensor fits tightly against the back of the cathode graphite flow plate, dividing the flow field into several insulating zones. By measuring the current in each zone, real-time current density data of the fuel cell is obtained. The data acquisition system is a multi-channel acquisition system that transmits the collected signals to the data processing software via a USB interface. The software features two-dimensional and three-dimensional real-time visualization windows and records the changes in current density values ​​in each zone.

[0037] Figure 2 This is a schematic diagram of the circuit principle of the current density tester's PCB sensor. The current flowing through the matrix-partitioned copper foil 1 flows through copper conductor 2 into the external chip resistor 3. The end of the external chip resistor 3 is connected to copper conductor OUT 6. Both ends of copper conductor OUT 6 have metal vias 4 connected to the underlying copper foil 5. The current from each unit partition is ultimately concentrated into the underlying copper foil 5. A signal line 7 leads from the input end of the external chip resistor 3. The output port of the external chip resistor is at the same potential as the underlying copper foil 5. The underlying copper foil is connected to the common test port of the test probe socket. Each signal line 7 connects to the corresponding port on the test probe socket, transmitting the test signal to the data acquisition system for processing.

[0038] Figure 3 The diagram below shows a side cross-section of the sensor on the PCB board of a current density tester. The top layer 1 is a matrix partitioned copper foil. Each partition is independent and insulated from each other, preventing current from conducting laterally. The top matrix partitioned copper foil is connected to the copper conductor 2 of the internal routing layer via a metal through-hole 4. A serpentine wiring method is used to ensure that the output impedance of each matrix partitioned copper foil 1 to the external chip resistor 3 is consistent, forming multiple equal-impedance copper conductors 2. The current in each partition of the top layer flows through the copper conductor 2 to the external chip resistor 3, converges to the bottom copper foil 5, and is ultimately conducted out through the cathode current collector. The input end of the external chip resistor 3 is connected to a signal line 7. The output end of the external chip resistor 3 is connected to the common end of the test pin COM and the bottom copper foil via a metal through-hole, forming an equipotential. The voltage signal between the signal line 7 and the common end of COM is transmitted to the data acquisition system.

[0039] The number of rows of the matrix partition copper foil 1 is not less than 5, the number of columns is not less than 5, and the number of rows and columns can be customized.

[0040] Among them, the external chip resistor 3 is a low-temperature drift resistor with a temperature drift coefficient of 50ppm. When the temperature changes from 25°C to 120°C, the resistance value of the resistor changes by less than 0.01%. The resistor is small in size and high in power, can withstand large currents, and has a resistance value of 0.1Ω, which has higher detection accuracy.

[0041] Among them, the data acquisition system has an acquisition accuracy of up to 0.3mV, and the collected data is uploaded to the computer via USB communication.

[0042] Figure 4 After the displayed data is transmitted to the computer, it is processed by an algorithm and displayed in real time in the form of a three-dimensional bar graph, which more intuitively presents the size of the current density value of each partition.

[0043] In this embodiment, the PCB sensor for testing the current density distribution of the fuel cell is clamped between the cathode graphite flow channel plate and the cathode current collecting plate. The active detection area is 25 cm 2 By controlling the hydrogen, air, and temperature conditions required by the fuel cell, the current density distribution of different membrane electrode systems can be tested. Furthermore, the fuel cell's geometric structure parameters, installation torque, gas temperature, pressure, and other parameters can be evaluated to analyze fuel cell problems.

[0044] The contents not described in detail in the specification of this utility model belong to the prior art known to those skilled in the art. Although the above describes the illustrative embodiments of the utility model to facilitate understanding of the utility model by those skilled in the art, it should be understood that the utility model is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various modifications are within the spirit and scope of the utility model as defined and determined by the appended claims, such modifications are obvious, and all inventions and creations utilizing the concepts conceived by the utility model are protected.

Claims

1. A device for testing the current density of a fuel cell, characterized in that: The device includes a fuel cell, a data acquisition system and a host computer; wherein: The assembly structure of the fuel cell is in the order of anode end plate, anode current collecting plate, anode graphite flow channel plate, MEA membrane electrode, cathode graphite flow channel plate, PCB board sensor, cathode current collecting plate, and cathode end plate; The data acquisition system is a multi-channel acquisition system that transmits the collected segmented voltage signals to the data processing software of the host computer through the USB interface. The data processing software has two-dimensional and three-dimensional visual real-time display windows and can record the changes in the current density value of each partition; The PCB sensor is located between the fuel cell's cathode graphite flow channel plate and the current collecting plate. The top layer of matrix partitioned copper foil is tightly attached to the back of the cathode graphite flow channel plate, dividing the flow field area of ​​the cathode graphite flow channel plate into several areas. The areas are insulated from each other. By detecting the current flowing through each area, real-time current density data of the fuel cell is obtained. The PCB sensor is provided with multiple measurement and acquisition units, which are arranged from top to bottom along the thickness direction of the PCB sensor: a top current collection area, a metal through-hole running through the PCB sensor, two internal wiring layers, and a bottom copper foil layer; wherein: The top current collection area includes a plurality of top matrix partitioned copper foils arranged in a matrix; the area outside the PCB sensor includes a plurality of chip resistors, each of which is connected to the top matrix partitioned copper foils in a one-to-one correspondence via internal copper conductors; the top matrix partitioned copper foils and the internal copper conductors are connected via metal through-holes that penetrate the PCB sensor; the metal through-holes on the end pads of the chip resistors are connected to the bottom copper foil; and the ends of each unit conductor are connected to the bottom copper foil via metal through-holes. The top current collection area is in close contact with the back of the fuel cell cathode graphite flow channel plate. The current from the cathode graphite flow channel plate flows through each top matrix partition copper foil unit in turn, flows into the internal copper wire corresponding to each unit through the metal through-hole, flows into the external chip resistor of each unit, passes through the external chip resistor and the metal through-hole at the end of the wire, and finally collects into the bottom copper foil. The current flowing through the matrix partition copper foil (1) flows into the external chip resistor (3) through the copper wire (2), the end of the external chip resistor (3) is connected to the copper wire OUT (6), both ends of the copper wire OUT (6) have metal through holes (4) connected to the bottom copper foil (5), and the current of each unit partition is finally collected to the bottom copper foil (5); the input end of the external chip resistor (3) leads to a signal line (7), the output port of the external chip resistor and the bottom copper foil (5) are at the same potential, the bottom copper foil is connected to the common test port of the test needle seat, and the signal line (7) of each channel is connected to the corresponding interface of the test needle seat, and the test signal of each channel is transmitted to the data acquisition system for processing; The bottom copper foil fits tightly against the cathode current collecting plate inside the fuel cell, conducting the total current out; The conductor widths of the two internal wiring layers are both designed to be 2 mm. The lengths of the conductors of each unit are made equal through equal impedance wiring, which allows large currents to pass through and ensures that the impedance of each unit conductor is consistent.

2. The device for fuel cell current density zoning test according to claim 1, characterized in that: The top current collection area, internal conductors, metal through-holes and bottom copper foil are all made of copper; the copper thickness is uniformly 75 μm; The top current collection area and the bottom copper foil surface are both gold-plated, and the gold plating thickness is 0.05 μm; The top layer matrix partition copper foil units in the top layer current collection area have equal areas, are independent and insulated from each other.

3. The device for fuel cell current density zoning test according to claim 1, characterized in that: Each chip resistor is fixed to the PCB sensor by welding. The chip resistor is a low-temperature drift resistor with a temperature drift coefficient of 50ppm. When the temperature changes from 25°C to 120°C, the resistance value of the resistor changes by less than 0.01%. The resistance value is 0.1Ω. The chip resistor elements used in each unit are the same.

4. The device for fuel cell current density zoning test according to claim 1, characterized in that: The data acquisition system has an acquisition accuracy of 0.3mV, and the collected data is uploaded to a computer via USB communication.

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