부스트 컨버터의 전류 피크 값에 따른 배터리 수명특성 분석

Abstract

At present, batteries connected in series, parallel, or series–parallel are used as energy sources in electrically propelled ships and other electric vehicles. In addition, lithium-based batteries, such as lithium polymer and lithium phosphate batteries, are widely used in these systems. Even though such batteries are used in a variety of electronic devices, from small devices such as mobile phones to larger devices, their lifespans are affected by a number of factors, including the number of charge and discharge cycles they undergo, the types of power sources they use for charging, and the characteristics of their discharging currents. The characteristics of the main discharge current are the C-rate, which represents the magnitude of the discharge current, and the current noise, which represents the harmonic inclusion. In the present study, we designed a boost converter that, when connected to the battery, could control both its peak value (ripple) and its harmonic content, while allowing it to maintain a constant output current. Moreover, we analyzed and observed the changes in both its lifetime and temperature, with respect to the peak value of its current using images collected by a thermal imaging camera over 300 discharge cycles, as well as internal resistance measurements made after the last cycle. Ultimately, it was confirmed that the battery life shortened as the peak value of the discharge current increased.