1,721,010 research outputs found

    Observability analysis of a Li-ion cell equivalent circuit model based on interval arithmetic

    No full text
    States observability is a crucial aspect in the system control and optimization. In the battery modelling context, the equivalent circuit model (ECM) observability is often taken for granted without addressing the impact of input, uncertain parameters, and the choice of the open circuit potential (OCP) fitting function. In this work, a non-linear interval-based approach is adopted to obtain guaranteed observability conditions for the ECM. The analysis shows that different OCP functions, with comparable fit, lead to different result in terms of model observability and there exist state-input combinations potentially non-observable, when the input time derivative and uncertain parameters are considered

    Analyzing cell-to-cell heterogeneities and cell configurations in parallel-connected battery modules using physics-based modeling

    Full text link
    In parallel-connected cells, cell-to-cell (CtC) heterogeneities can lead to current and thermal gradients that may adversely impact the battery performance and aging. Sources of CtC heterogeneity include manufacturing process tolerances, poor module configurations, and inadequate thermal management. Understanding which CtC heterogeneity sources most significantly impact battery performance is crucial, as it can provide valuable insights. In this study, we use an experimentally validated electrochemical battery model to simulate hundreds of battery configurations, each consisting of four cells in parallel. We conduct a statistical analysis to evaluate the relative importance of key cell-level parameters, interconnection resistance, cell spacing, and location on performance and aging. The analysis reveals that heterogeneities in electrode active material volume fractions primarily impact module capacity, energy, and cell current, leading to substantial thermal gradients. However, to fully capture the output behavior, interconnection resistance, state of charge gradients and the effect of the temperature on parameter values must also be considered. Additionally, module design configurations, particularly cell location, exacerbate thermal gradients, accelerating long-term module degradation. This study also offers insights into optimizing cell arrangement during module design to reduce thermal gradients and enhance overall battery performance and longevity. Simulation results with four cells indicate a reduction of 51.8% in thermal gradients, leading to a 5.2% decrease in long-term energy loss
    corecore