The degradation characteristics and mechanism of Li[Ni0.5Co0.2Mn0.3]O2 batteries with high frequency current ripple excitation

Abstract

Lithium-ion battery life is critical to the safe and stable operation of electric vehicles. During long-term operation, the chemical composition of the battery undergoes irreversible changes. This irreversible change can cause the battery to experience capacity loss and performance degradation. Power electronic devices have a large amount of high frequency current ripple, characterized by zero average current but the root mean square (RMS) value is not zero. Lithium-ion batteries excited by high frequency voltage ripple can generate additional heating, which may accelerate the capacity loss rate. In this paper, in order to distinguish the effects of temperature and high-frequency ripple components on the battery, two control groups at different temperatures and four control groups with different high-frequency ripple currents were set up in the test. The positive electrode (PE) and negative electrode (NE) voltage curve matching method to is used to quantify the electrode material loss. The conclusion shows that the high-frequency ripple current slightly accelerates the capacity drop of the NE, which can have an impact on the capacity and performance of the full battery.