Effect of current on cycle aging of lithium ion batteries

Abstract

Abstract Nowadays, lithium ion batteries are increasingly spreading in different areas and therefore, it is very important to understand their aging behavior. According to the technical literature, battery aging can be dissociated in calendar aging and cycle aging. Calendar aging, in particular, depends on the temperature and state of charge (SoC). In addition to the previous factors, cycle aging also depends on the current rate, and charge/discharge cut-off voltages. In the literature, only a few papers have considered battery aging as a function of the charge/discharge current rate, but they agree that a higher current rate leads to faster battery aging. In any case, all of the tests have been conducted in a climactic chamber with a constant room temperature. However, even if the room temperature is controlled, for high current rates, the temperature of the battery cell increases, which makes it impossible to distinguish the aging due to the current from that due to the temperature. For this reason, in the present work, the authors focused on the lithium ion battery aging due to the current rate while maintaining a constant battery temperature using opportunely controlled Peltier cells. In this way, an interesting results was obtained, i.e. the cycle aging is not dependent on the current rate.