提出一种分层均衡电路,用于解决锂离子电池在串联成组时,由于单体电池的不一致性,产生的部分电池过充和过放的问题。分层均衡电路以单体电池荷电状态(state of charge,SOC)值作为均衡变量,将电池组分为3个小组,组内进行基于Buck变换器...提出一种分层均衡电路,用于解决锂离子电池在串联成组时,由于单体电池的不一致性,产生的部分电池过充和过放的问题。分层均衡电路以单体电池荷电状态(state of charge,SOC)值作为均衡变量,将电池组分为3个小组,组内进行基于Buck变换器的均衡;在各小组之间搭建Buck-Boost电路,进行组间均衡。组内均衡与组间均衡相结合,提高了均衡效率。在MATLAB/Simulink平台搭建的仿真结果表明,相对于基于Buck变换器和基于Buck-Boost变换器的均衡电路,分层均衡电路在静置、充电和放电3种工况下,均衡时间相比基于Buck的均衡电路分别降低了21%、18%和30%,相比基于Buck-Boost的均衡电路分别降低了17%、29%和15%。电池组的均衡实验表明,该电路提高了单体电池一致性,能将电池组SOC值极差控制在0.1%以内,解决部分电池过充和过放问题,同时提高了均衡效率。展开更多
Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing i...Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing in the field.The rapid transport of colloids through fractured rocks-as affected by the hydraulic properties of the flow system,the properties of fracture surface and the geochemical conditionshas not been sufficiently elucidated,and predictions of colloid transport through fractures have encountered difficulties,particularly at the field scale.This article reviews the current understanding of the mechanisms and modeling of colloid transport and retention in fractured rocks.Commonly used experimental techniques and approaches for conducting colloid transport experiments at different scales,ranging from the laboratory to the field scale,are summarized and commented upon.The importance of various interactions(e.g.,dissolution,colloid deposition,generation,mobilization and deposition of filling materials within fractures) between the flowing solution and the fracture walls(in many cases,with skin or coating on the host rock at the liquid-solid interface) has been stressed.Colloid transport through fractures of high heterogeneity has not yet been well understood and modeled at the field scale.Here,we summarize the current knowledge and understanding accumulated in the last two decades in regard to colloid and colloidassociated transport through fractures.Future research needs are also discussed.展开更多
文摘提出一种分层均衡电路,用于解决锂离子电池在串联成组时,由于单体电池的不一致性,产生的部分电池过充和过放的问题。分层均衡电路以单体电池荷电状态(state of charge,SOC)值作为均衡变量,将电池组分为3个小组,组内进行基于Buck变换器的均衡;在各小组之间搭建Buck-Boost电路,进行组间均衡。组内均衡与组间均衡相结合,提高了均衡效率。在MATLAB/Simulink平台搭建的仿真结果表明,相对于基于Buck变换器和基于Buck-Boost变换器的均衡电路,分层均衡电路在静置、充电和放电3种工况下,均衡时间相比基于Buck的均衡电路分别降低了21%、18%和30%,相比基于Buck-Boost的均衡电路分别降低了17%、29%和15%。电池组的均衡实验表明,该电路提高了单体电池一致性,能将电池组SOC值极差控制在0.1%以内,解决部分电池过充和过放问题,同时提高了均衡效率。
基金supported by the "Hundred Talents Program" of the Chinese Academy of Sciences (No. 724)the National Key Technology R&D Program of the Ministry of Science and Technology of China (No. 2011BAC09B05)+1 种基金the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists(No. 2011T1Z27)the National Natural Science Foundation of China (No. 41171372)
文摘Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing in the field.The rapid transport of colloids through fractured rocks-as affected by the hydraulic properties of the flow system,the properties of fracture surface and the geochemical conditionshas not been sufficiently elucidated,and predictions of colloid transport through fractures have encountered difficulties,particularly at the field scale.This article reviews the current understanding of the mechanisms and modeling of colloid transport and retention in fractured rocks.Commonly used experimental techniques and approaches for conducting colloid transport experiments at different scales,ranging from the laboratory to the field scale,are summarized and commented upon.The importance of various interactions(e.g.,dissolution,colloid deposition,generation,mobilization and deposition of filling materials within fractures) between the flowing solution and the fracture walls(in many cases,with skin or coating on the host rock at the liquid-solid interface) has been stressed.Colloid transport through fractures of high heterogeneity has not yet been well understood and modeled at the field scale.Here,we summarize the current knowledge and understanding accumulated in the last two decades in regard to colloid and colloidassociated transport through fractures.Future research needs are also discussed.
