基于充电电压片段的电池健康状态自适应估计

Battery State of Health Adaptive Estimation Based on Charging Voltage Segments

  • 摘要: 准确、连续、高效的锂离子电池健康状态(State of health,SOH)估计对电动汽车的安全有效运行至关重要。然而,在工程实际中,碎片化的充放电行为只能生成片段数据,且仅包含电压、充电量等常规参数,这给现有方法带来了阻碍。针对上述难题,提出了基于充电电压片段的电池SOH自适应估计系统,其融合三种子方法实现了在任意充电片段下连续、准确的SOH估计。首先,建立了自适应估计系统中优先级最高的最佳片段估计法,探索了使用单一充电片段实现电池SOH的准确估计。基于相关分析和容量衰减特性,定义了最佳电压片段,最佳均方根误差(Root-mean-square error,RMSE)仅为0.012。其次,考虑到工程实际中最佳特征不完整致使估计失效的缺陷,设计了滑动采样估计法,实现了任意充电片段下的SOH连续估计,最佳RMSE达到0.017。最后,为了使自适应SOH估计系统在估计精度和估计连续性上达到平衡,基于SOH的短期稳定性,融合相邻循环充电信息,提出了相邻循环组合估计法。通过信息融合和片段组合以模拟最佳片段,最佳RMSE仅为0.014。三种子方法在估计精度、鲁棒性和稳定性上互相支撑、优势互补,为自适应估计系统提供有力保障。这项研究成果对电池智能管理及状态估计技术的工程应用具有重要意义和参考价值。

     

    Abstract: Accurate, continuous, and efficient estimation of the state of health(SOH) for lithium-ion batteries is crucial for the safe and effective operation of electric vehicles. However, in engineering practice, the fragmented charging and discharging behavior can only generate fragmented data, and only contain conventional parameters such as voltage and charge capacity, which brings obstacles to the existing methods. To address the aforementioned challenges, an adaptive battery SOH estimation system based on charging voltage segments is proposed, which integrates three sub-methods to achieve continuous and accurate SOH estimation under arbitrary charging segments. Firstly, the highest-priority optimal segment estimation method is established within the adaptive estimation system, exploring the accurate estimation of battery SOH using a single charging segment. Based on correlation analysis and capacity degradation characteristics, the optimal voltage segment is defined, achieving a minimal RMSE of just 0.012. Secondly, considering the limitation of incomplete optimal features in practical engineering, which may lead to estimation failure, a sliding sampling estimation method is designed. This method enables continuous SOH estimation under arbitrary charging segments, achieving an optimal RMSE of 0.017. Finally, to balance estimation accuracy and continuity in the adaptive SOH estimation system, a neighboring-cycle combination estimation method is proposed based on the short-term stability of SOH. By integrating information from adjacent charging cycles and combining segments to simulate the optimal segment, this method achieves an optimal RMSE of only 0.014. The three sub-methods support and complement each other in estimation accuracy, robustness and stability, and provide a strong guarantee for the adaptive estimation system. The research findings presented hold significant importance and offer valuable insights for the engineering application of battery intelligent management and state estimation technologies.

     

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