锂离子电池力学特性参数可作为电池循环充放电导致的内部结构变化、损伤与性能衰退的评估依据,然而现有检测方法难以无损获取实际工况下的电池力学特性参数。超声波形特征能够反演电池内部结构的微小变化,与电池力学特性参数变化密切相...锂离子电池力学特性参数可作为电池循环充放电导致的内部结构变化、损伤与性能衰退的评估依据,然而现有检测方法难以无损获取实际工况下的电池力学特性参数。超声波形特征能够反演电池内部结构的微小变化,与电池力学特性参数变化密切相关,可准确表征电池力学特性参数。该文提出一种基于锂离子电池声学均一化模型与粒子群优化算法的电池力学特性参数估计方法。基于均匀化理论对电池多层结构进行简化,建立电池声学均一化模型。搭建电池超声检测平台,获取超声实验数据,为力学特性参数估计提供数据支撑。基于粒子群优化算法联合声学均一化模型进行仿真优化,利用仿真波形逼近实验波形,不断迭代优化模型,反推出此时电池整体有效杨氏模量与整体有效密度等力学特性参数。最后,通过高斯过程回归算法建立融合力学特征的锂离子电池荷电状态(state of charge,SOC)估计模型,对比融合不同特征对SOC估计精度的影响。实验结果表明,融合力学特征可以有效提高SOC估计精度。在动态工况下,SOC估计值的均方根误差为1.92%,平均绝对误差在1.68%,验证了利用力学特性参数进行SOC估计的可靠性与准确性。展开更多
Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30...Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30, 50 ℃/min. The purpose is to obtain pyrolysis characteristics and kinetic parameters of medical waste. The experimental results indicate that the pyrolysis behavior of the MTT sample is in agreement with its main ingredient of PVC, appearing two stair stepping stages. The influence of the additives in MTT on pyrolysis behavior was also revealed, which could improve MTT pyrolysis at lower temperature in the first stage, and cause obvious unsmoothness and asymmetry of the second DTG peak. Four n-order kinetic models of Coats-Redfern, Ozawa, Kissinger and Freeman-carroll were used to get the kinetic parameters. Furthermore, a novel ＂two-step four-reaction model＂ was established to simulate the whole continuous process. The different methods and the kinetic parameters thus obtained were discussed and compared with each other in literatures. The reasons of deviation among kinetic values were tried to be elucidated. The new established model could more satisfactorily describe the pyrolysis process of MTT, being more mechanistic and conveniently serving for the engineering.展开更多
文摘锂离子电池力学特性参数可作为电池循环充放电导致的内部结构变化、损伤与性能衰退的评估依据,然而现有检测方法难以无损获取实际工况下的电池力学特性参数。超声波形特征能够反演电池内部结构的微小变化,与电池力学特性参数变化密切相关,可准确表征电池力学特性参数。该文提出一种基于锂离子电池声学均一化模型与粒子群优化算法的电池力学特性参数估计方法。基于均匀化理论对电池多层结构进行简化,建立电池声学均一化模型。搭建电池超声检测平台,获取超声实验数据,为力学特性参数估计提供数据支撑。基于粒子群优化算法联合声学均一化模型进行仿真优化,利用仿真波形逼近实验波形,不断迭代优化模型,反推出此时电池整体有效杨氏模量与整体有效密度等力学特性参数。最后,通过高斯过程回归算法建立融合力学特征的锂离子电池荷电状态(state of charge,SOC)估计模型,对比融合不同特征对SOC估计精度的影响。实验结果表明,融合力学特征可以有效提高SOC估计精度。在动态工况下,SOC估计值的均方根误差为1.92%,平均绝对误差在1.68%,验证了利用力学特性参数进行SOC估计的可靠性与准确性。
基金Project(50378062) supported by the National Natural Science Foundation of ChinaProject(09JCYBJC08100) supported by the Natural Science Foundation of Tianjin City,China
文摘Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30, 50 ℃/min. The purpose is to obtain pyrolysis characteristics and kinetic parameters of medical waste. The experimental results indicate that the pyrolysis behavior of the MTT sample is in agreement with its main ingredient of PVC, appearing two stair stepping stages. The influence of the additives in MTT on pyrolysis behavior was also revealed, which could improve MTT pyrolysis at lower temperature in the first stage, and cause obvious unsmoothness and asymmetry of the second DTG peak. Four n-order kinetic models of Coats-Redfern, Ozawa, Kissinger and Freeman-carroll were used to get the kinetic parameters. Furthermore, a novel ＂two-step four-reaction model＂ was established to simulate the whole continuous process. The different methods and the kinetic parameters thus obtained were discussed and compared with each other in literatures. The reasons of deviation among kinetic values were tried to be elucidated. The new established model could more satisfactorily describe the pyrolysis process of MTT, being more mechanistic and conveniently serving for the engineering.
