Capacity degradation prediction model of LiMn_0.6Fe_0.4PO₄/LiNi_0.5Co_0.2Mn_0.3O₂ composite cathode materials for lithium-ion batteries

Battery lifetime prediction is critical to successfully introducing new products to the market, and a long testing time will affect the promotion of the product. In this paper, the ambient temperature (25–45 ℃), charge cut-off voltage (CCOV) (4.2–4.4 V), and discharge rate (0.5–2C) to performance degradation of LiMn_0.6Fe_0.4PO₄ and LiNi_0.5Co_0.2Mn_0.3O₂ (LMFP/NCM) composite cathode batteries are revealed by the accelerated life test. The results indicated that the CCOV in the range of 4.3 \(-\) $-$ 4.4 V was significant. The discharge rate effect was less affected (no more than 2C). Furthermore, single stress factor and multi-stress factor models consisting of temperature, discharge rate, CCOV, and state of health (SOH) for cycle life prediction are developed based on the revised Arrhenius equation and the inverse power law equation. It is shown that the proposed life model can accurately predict battery capacity degradation, and the estimation error is less than 2%. The developed model helps to predict the lifetime of the battery under different SOH and optimize the operation conditions of the battery.