Introduction to the development of fuel cell test systems
1. Sang Yingjun    2. Fan Yuanyuan
(1 Huaiyin Institute telecommunications system; Huaiyin Institute project department 2, Huaian 223001)
Abstract: This paper systematically introduces the research status and development level of fuel cell test systems at home and abroad. The basic theory of the test system. It is summarized from the aspects of test purpose, main parameters, basic characteristics and basic structure of the system. Through the various data listed in this article, it is not difficult to see that fuel cell testing technology is shortening the fuel cell development cycle. Improving quality and reducing costs are important.
Keywords: fuel cell  Test system  Performance parameter
With the global demand for energy and the increase in human environmental requirements. Each country's fuel cell research and development H benefits increased. Fuel cells are one of the most promising technologies for providing clean and efficient energy to cars and residents. Fuel cell engines are considered to be the most promising new energy power system to replace internal combustion engines. The fuel cell test system is not only important in the development stage of the fuel cell system, but also indispensable for maintaining the normal operation of the battery even after it is put into use. Powerful testing capabilities provide reliable monitoring of fuel cells. Providing a flexible structure with this capability, the scientific community can easily design their systems to track advances in fuel cell technology.
1 . The current research status and level of fuel cell test system at home and abroad
Since the fuel cell is still in the development stage, the automotive industry has not yet developed a standard test instrument for fuel cells. Not to mention the uniform specification of test instrument suppliers. Many companies are beginning to approach this challenge to research solutions that accurately test fuel cells. The most striking of these companies is the United States of Hydrogenics Corporation and National Instruments (NationalInstnlments, referred to as NI), which introduced a number of software and hardware test products. Compatible with a wide range of fuel cells, measuring almost all design specifications: Hydrogenics ' Greenljght is the world's largest fuel cell test system for cattle production. It is a global leader in fuel cell industry test diagnostic equipment. Nl is a global leader in computer-based measurement, and many leading fuel cell manufacturers use NI hardware and software T- tools to test fuel cells at all stages of development . In the entire battery industry developed a fuel cell test systems only a handful of companies, H are foreign manufacturers by the year 2004. In order to enable experts in the development of fuel cells to use measurement, control, analysis and visualization tools for evaluation, Wuhan Lixing Testing Equipment Co., Ltd. has closely developed the world's leading fuel cell testing system, and has developed its own domestic fuel cell testing system. And in January 2004 launched the first domestic fuel cell test system. The introduction of this system fills the gap in China's fuel cell testing field. It has an extraordinary significance in promoting the milestones in the development of the domestic fuel cell industry.
2 . Basic theory of fuel cell test system
2 . 1 test purpose
Although the research, development, manufacture and application of the overall target portion f J are different. They are similar for fuel cell detection and evasive project requirements. For Ding's R&D department, the test requirements are sufficient to determine output energy, service life and battery pack durability. In the design acceptance phase, the main task is to optimize the design for mass production. And reduce the total cost of the stack without reducing efficiency. For the production of Ding. The fuel cell is required to meet the specifications. In actual use, it is very important to monitor the battery life and working condition. Fortunately, these different tasks have similar requirements for battery test systems.
2 . 2 main features of the test system
1 isolation. The fuel cell test system first performs various measurements that require signal conditioning. The original signal can then be digitized by the data acquisition system. The largest stack has hundreds of single cells. Therefore, the voltage measurement requires a few white. Common mode rejection of volts. therefore. The test must not only have multiple channels per channel that can read l - 10V . It is also necessary to maintain isolation of up to several hundred volts between each and the last battery of the stack.
2 The data acquisition system must be able to expand. Since the number of channels in the fuel cell test system can range from 100 to more than 1000 . So the data acquisition system must be able to scale. And these systems also require attenuation and amplification of the signal.
3 modular. Modularity is also required for today's test systems. Because test systems must be able to change as production and verification technologies change.
4 calibration. Any test system should be calibrated to ensure that the measurements are valid and accurate.
2 . 3 test main performance parameters
Fuel cell test systems require precise monitoring and control of hundreds of measurements. Fan from the flow and temperature of fuel and oxidant, pressure and humidity to the output voltage and current of the fuel cell stack. Testing the performance of a fuel cell is important, and monitoring the variables that affect performance is more important, but the most important is to control these variable parameters, and safe operation is also critical. So the main parameters of monitoring control are:
(1) Voltage. In the case of a load, the output voltage of the cell will be reduced from O open circuit voltage of about 1V. Around 6V . Knowing the voltage of each cell can get a closer look at the health of the stack. If a single battery shows a different voltage, it indicates that the battery has a problem, or the temperature is abnormal, or the electrode is flooded. Testing the voltage of a single cell or stack allows the fuel cell to be properly operated, tested and designed.
(2) Current. The output current is sometimes very high, so it is usually measured by the Gaussian effect. This method can be used to test the current and proportionally convert it into a current reading without directly using the wire.
(3) Temperature. To generate electricity efficiently. The PEMFC must be operated in the range of 60 - 80 °C. The purpose of monitoring temperature is to optimize temperature changes to increase output power. Thermocouples and resistors are temperature sensors. It is a good sensor for monitoring battery pack temperature and reaction gas temperature.
(4) Humidity. Each diaphragm of the battery unit must maintain a certain humidity, too dry or too wet will affect the efficiency of the fuel cell. Therefore, it is very important to measure and control the humidity of the fuel cell. A test method for moisture by an electronic humidity sensor, based on an output proportional to the size of 4 humidity - 20mA current, input channel test equipment can be read into the current signal.
(5) Gas pressure. In many applications, the airflow pressure is large and this pressure must be monitored and managed. The pressure is measured by a pressure sensor and signal conditioned.
(6) Gas flow rate. The hydrogen flow rate is typically measured using a mass flow meter that produces a pulse proportional to the gas flow rate. These pulses are then monitored by the counter/timer interface board. And use software to convert to traffic. The electrons can control the pressure and flow through the voltage or current output from the test bench.
(7) Load. A programmable load can be used to change the resistance. Changing the resistance can be done by connecting the resistors in parallel using a controllable GPIB load device or via a digital relay. The first method can install a separate unit to change the resistance applied to the stack through GPl0 . The second method can use relays and switches to change the resistance.
2 . 4 fuel cell test system basic structure
The fuel cell test system consists of two major pieces of hardware and software. The hardware part mainly has controllers, sensors and loading devices; the controller is mainly based on computer control. This approach takes full advantage of the computer: fast, memory and scalable. The software is easy to upgrade and flexible, and the user interface is friendly. Users can easily perform programming and experiments of various levels of complexity. Table 1 lists the basic structural elements of the fuel cell test system.
3 . in conclusion
T -trainers are constantly applying new methods to fuel cell testing. Constantly seeking reliable, accurate and flexible test systems to help shorten development cycles, improve fuel cell quality and reduce costs. To develop the next generation of fuel cells. With the fuel cell development environment, government and consumer pressures, coupled with the government's huge investment, the development and application of fuel cell test systems will make greater progress.
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