二次電池 保護 시스템用 複合素子 및 퓨즈 低融點 金屬可鎔體 鎔斷特性 硏究

Abstract

Secondary battery based on energy storage device may cause a fire or an explosion due to micro current change in addition to the situation of short-circuit inrush current, and safety can not be secured with a general passive operation limit current type fuse. Therefore, it is necessary for the protection device to satisfy both the limit current type operation in the full short-circuit inrush current and the current detection operation characteristic in the small current change situation. For this operation, a fuse for the current detection type secondary battery protection circuit can be applied. In addition, the secondary battery may cause a fire and an explosion in a temperature rise condition not accompanied by a change in current, which can be a serious injury due to a danger occurring during use of the portable electronic device. Therefore, a current control protector is required for the temperature rise of the secondary battery during the use of the portable electronic device, and the resettable protection device using the bimetal is superior in operating speed and temperature sensitivity as compared with the general PCT device. The first purpose of this study is to develop a protection device that can safely operate in a wide range of abnormal current and state by operating in high risk of large capacity secondary battery through the design of low melting fuse elements alloy of current sensing type fuse design. Second, the material and structure of the Fe-36wt% Ni Invar alloy and the thermal expansion pure metal of the bimetallic resettable fuse are designed so as to secure the safety of the portable electronic device applying the small secondary battery. The experimental results showed that the I-T and V-T operating characteristics were satisfied through the design of the alloy of the current sensing type self-contained low-melting fuse elements and the exothermic resistance. That is, the current sensing operation terminal characteristics to prevent the short circuit over-current and the micro current change of the secondary battery and the fuse protection terminal operation characteristics in the complete short circuit state can be secured and the safety against the abnormal current generation can be ensured. In the case of Sn-Bi alloy and Sn-Ag-Cu alloy with relatively low temperature, it was not possible to apply it due to the temperature problem in the automatic PCB mounting process of small and medium secondary battery. But the safety can be secured in a wide range at the large capacity secondary battery. In case of protection device with temperature sensing operation, it is possible to realize various operating characteristics at a desired temperature by adjusting the thickness of pure silver and pure copper bonded by plating to the invar alloy. Thereby preventing accident of temperature change and micro current change. In addition, the range of operation stability was confirmed by checking the I2T value, and the necessity of the main protection device against the current inflow exceeding the operating speed range was confirmed. The experiments, the design of the protection system to secure the safety of the secondary battery based energy storage system, which is a new power source system, and the direction of the safe circuit and parts design for the protection device application were suggested.