Cycle-life of Lithium-ion Capacitors: Factors Influencing Aging

A comprehensive study of the factors influencing the cycle life of Lithium-ion capacitors (LICs) at different stages of aging is essential for a promising LIC energy management system. This paper studies the factors influencing the aging of LICs. The commercially available 2100F Musashi LIC cells are chosen to perform cyclic aging experiments under different test conditions. The test matrix includes different temperatures (40^oC, 50^oC), charge-discharge rates (C-rate) (4C,53C), and depth of discharge (DoD) levels (100%,60%). The results indicate that C-rate is inversely proportional to the capacitance degradation of LIC. At a low C-rate, both the cyclic aging and calendar aging component contributes to the cell’s degradation. Similarly, temperature and DoD significantly influence the degradation of the LIC, and both are linearly related to aging. However, these parameters are highly sensitive to the other operating conditions of the cells. Finally, the Arrhenius equation has been applied to the test results and qualitatively analyzed the LIC degradation mechanism.