Design Of Hydrogen Storage Alloy Testing System & Ni-MH Battery Management System

As increasing attention has been paid to hydrogen energy, hydrogen storage alloys have been widely investigated recently. However, the lack of relevant testing equipments, especially for Pressure-Composition-Temperature (PCX) testing, has become a key factor hindering the research on hydrogen storage alloys in China. As a successful application of hydrogen alloys, Ni-MH battery has achieved great progress in the area of small secondary batteries and also has a promising prospect in Hybrid Electric Vehicle (HEV) application. For this purpose, accurate determination of the state of charge (SOC) of Ni-MH batteries to prevent the batteries from over charging or over discharging is a key technology. The first aim of this paper is to develop an automatic testing equipment for hydrogen storage alloys. At the same time, a Ni-MH battery management system is developed to explore the SOC of Ni-MH batteries.The paper discusses the principle of PCT testing equipment; the over-all control scheme for the gas-solid reaction controller is decided. ADuC812 is chosen as the core of the control system, which communicates with PC through serial port. By manipulating the solenoid valves through solid state relay (SSR), the system can control the process of the reaction as programmed. Some safety mechanisms were adopted to protect the sensitive devices of the system, which makes the system safer. The paper presents the detailed design of the hardware circuits and control software. The hardware circuits include the main control board, the digital I/O board and the LED display board. The software includes the data acquiring program, the data processing program, the valves manipulating program, the system-testing program, the automatic PCT program and the interface program on the PC.The paper designs a manual control system and a flow acquisition system of a device for activating hydrogen storage alloys. By choosing different scale mass flow controllers, the system can calculate the flow of the hydrogen realeased by activated hydrogen storage alloys accurately in a wide range.The paper designs a Ni-MH battery management system for HEV application. The system monitors the current, voltage, temperature and internal pressure of the cells. According to the variation of these parameters (especially the change of the internal pressure) and the charge and discharge characteristics of the battery, the system judges the SOC of the battery and controls the process of charging and discharging. The paper givesthe detailed design of the hardware circuits and the control software. The hardware circuits include the main control board, data acquiring board and human machine interface (HMI) board. Through multiplexer and decoding circuits, the system can acquire signals of up to 32 cells. Through the HMI Board, the control reference can easily be modified when needed.