Bharathraj S, Adiga S P, Patil R S, Mayya K S, Song T, Sung Y
Materials and Simulations Group (SAIT-India), Samsung R&D Institute India-Bangalore, Bangalore, India.
Energy Materials Lab, SAIT, Samsung Electronics, Suwon, Republic of Korea.
Sci Rep. 2019 Apr 29;9(1):6576. doi: 10.1038/s41598-019-42583-2.
Degradation mechanisms leading to deterioration in the battery performance is an inevitable phenomenon. Although there are detailed physics and equivalent circuit based models to predict the losses incurred due to degradation in estimating the health of the battery, they are either incomplete, computationally expensive or both. In this study, we present a very simple and elegant, chemistry independent mathematical analysis, which accurately calculates resistive and capacitive components of cycle-life related losses in a battery system. We demonstrate that discharge profiles obtained at any given degradation state of the battery can be represented by an analytical function, with its origin lying at the heart of battery dynamics, using simple parameter fitting. The model parameters relate to the battery electrochemical potential, resistance and capacity. We first validate our protocol using simulated cycling data from a degrading lithium-ion battery system modeled with detailed electrochemical thermal calculations and show that the estimates of capacity and power fades are >99% accurate using our method. Further, we construct a unique phase space plot of normalized energy, power that gives a compact representation of quantitative and qualitative trend of the degradation state of the system, as well as available power and energy.
导致电池性能恶化的降解机制是一种不可避免的现象。尽管有基于详细物理和等效电路的模型来预测在评估电池健康状况时由于降解而产生的损失，但它们要么不完整，计算成本高，要么两者兼而有之。在本研究中，我们提出了一种非常简单且精妙的、与化学无关的数学分析方法，该方法能准确计算电池系统中与循环寿命相关损失的电阻和电容分量。我们证明，通过简单的参数拟合，在电池的任何给定降解状态下获得的放电曲线都可以由一个解析函数表示，其根源在于电池动力学的核心。模型参数与电池的电化学势、电阻和容量有关。我们首先使用来自一个通过详细电化学热计算建模的降解锂离子电池系统的模拟循环数据验证了我们的协议，并表明使用我们的方法，容量和功率衰减的估计准确率超过99%。此外，我们构建了一个独特的归一化能量 - 功率相空间图，它紧凑地表示了系统降解状态的定量和定性趋势，以及可用功率和能量。
