Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indis...Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indispensable for guaranteeing the secure and optimal functionality of the batteries.The impedance spectrum has garnered growing interest due to its ability to provide a valuable understanding of material characteristics and electrochemical processes.To inspire further progress in the investigation and application of the battery impedance spectrum,this paper provides a comprehensive review of the determination and utilization of the impedance spectrum.The sources of impedance inaccuracies are systematically analyzed in terms of frequency response characteristics.The applicability of utilizing diverse impedance features for the diagnosis and prognosis of batteries is further elaborated.Finally,challenges and prospects for future research are discussed.展开更多
Online parameter identification is essential for the accuracy of the battery equivalent circuit model(ECM).The traditional recursive least squares(RLS)method is easily biased with the noise disturbances from sensors,w...Online parameter identification is essential for the accuracy of the battery equivalent circuit model(ECM).The traditional recursive least squares(RLS)method is easily biased with the noise disturbances from sensors,which degrades the modeling accuracy in practice.Meanwhile,the recursive total least squares(RTLS)method can deal with the noise interferences,but the parameter slowly converges to the reference with initial value uncertainty.To alleviate the above issues,this paper proposes a co-estimation framework utilizing the advantages of RLS and RTLS for a higher parameter identification performance of the battery ECM.RLS converges quickly by updating the parameters along the gradient of the cost function.RTLS is applied to attenuate the noise effect once the parameters have converged.Both simulation and experimental results prove that the proposed method has good accuracy,a fast convergence rate,and also robustness against noise corruption.展开更多
A multiphase NiAl-28Cr-5.85Mo-0.15Hf alloy, which was directionally solidified （DS） in an Al2O3-SiO2 mold by standard Bridgman method and then underwent prolonged solution and aging treatment was prepared. The micro...A multiphase NiAl-28Cr-5.85Mo-0.15Hf alloy, which was directionally solidified （DS） in an Al2O3-SiO2 mold by standard Bridgman method and then underwent prolonged solution and aging treatment was prepared. The microstructure, tensile properties as well as tensile creep of the heat-treated alloy at different temperatures were studied. The alloy was composed of NiAI, Cr（Mo） and Hf-rich phase and small amount of fine Heusler phase （Ni2AlHf）. Although the present alloy exhibited high tensile strength at low temperature, it was weaker than that of system with high content Hf but still stronger than that of many NiAl-based alloys at high temperatures. The fracture toughness is lower than that of DS NiAl-28Cr-6Mo alloy. Nevertheless, advantageous effects on the mechanical properties, i.e. the decrease in brittle-to-ductile transition temperature （BDTT） were obtained for the low content of Hf. The obtained creep curves exhibit conventional shape： a short primary creep and long accelerated creep stages. The rupture properties of the heat-treated alloy follow the Monkman-Grant relationship, which exhibits similar creep behavior to that of NiAl/Cr（Mo） system with high Hf content.展开更多
1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highes...1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highest strength alloy to be developed as reported in recent researches[1-8].The tensile strength of this kind of alloy is usually around 2.0 GPa.The yield strength of a maraging steel re-cently fabricated by laser powder bed fusion can reach as high as about 2.4 GPa,but it is unfortunate that the elongation is merely about 1%[9].So it seems that 2.0 GPa yield strength is an upper limitation for this kind of alloy.To break through this limitation,it is of significance to establish a new composition design strat-egy.For instance,recent work[10]reported a medium Mn steel doped with Al and V elements,which exhibits an ultra-high yield strength of 2.21 GPa with 15%uniform elongation after thermo-mechanical processing.In another aspect,the design using multi-ple principal elements and additional elements to form a high en-tropy alloy(HEA)should be a very promising pathway.展开更多
Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is ...Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is employed to refine grain sizes to a nanoscale.Nanocrystalline AZ61 Mg alloy with an av-erage grain size of less than 100nm was successfully obtained using FSP.Corresponding to this,the highest microhardness of the nano-grained region reached triple times that of AZ61 substrate.In prin-ciple,by applying multiple overlapping passes,it should be possible to produce any desired size thin sheet of nanostructure using this technique.We expect that the FSP technique may pave a way to large-scale structural applications of nanostructured metals and alloys.展开更多
文摘Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indispensable for guaranteeing the secure and optimal functionality of the batteries.The impedance spectrum has garnered growing interest due to its ability to provide a valuable understanding of material characteristics and electrochemical processes.To inspire further progress in the investigation and application of the battery impedance spectrum,this paper provides a comprehensive review of the determination and utilization of the impedance spectrum.The sources of impedance inaccuracies are systematically analyzed in terms of frequency response characteristics.The applicability of utilizing diverse impedance features for the diagnosis and prognosis of batteries is further elaborated.Finally,challenges and prospects for future research are discussed.
基金National Natural Science Foundation of China(Grant No.52107229)the Fund of Robot Technology Used for Special Environment Key Laboratory of Sichuan Province(Grant No.20KFKT02)。
文摘Online parameter identification is essential for the accuracy of the battery equivalent circuit model(ECM).The traditional recursive least squares(RLS)method is easily biased with the noise disturbances from sensors,which degrades the modeling accuracy in practice.Meanwhile,the recursive total least squares(RTLS)method can deal with the noise interferences,but the parameter slowly converges to the reference with initial value uncertainty.To alleviate the above issues,this paper proposes a co-estimation framework utilizing the advantages of RLS and RTLS for a higher parameter identification performance of the battery ECM.RLS converges quickly by updating the parameters along the gradient of the cost function.RTLS is applied to attenuate the noise effect once the parameters have converged.Both simulation and experimental results prove that the proposed method has good accuracy,a fast convergence rate,and also robustness against noise corruption.
文摘A multiphase NiAl-28Cr-5.85Mo-0.15Hf alloy, which was directionally solidified （DS） in an Al2O3-SiO2 mold by standard Bridgman method and then underwent prolonged solution and aging treatment was prepared. The microstructure, tensile properties as well as tensile creep of the heat-treated alloy at different temperatures were studied. The alloy was composed of NiAI, Cr（Mo） and Hf-rich phase and small amount of fine Heusler phase （Ni2AlHf）. Although the present alloy exhibited high tensile strength at low temperature, it was weaker than that of system with high content Hf but still stronger than that of many NiAl-based alloys at high temperatures. The fracture toughness is lower than that of DS NiAl-28Cr-6Mo alloy. Nevertheless, advantageous effects on the mechanical properties, i.e. the decrease in brittle-to-ductile transition temperature （BDTT） were obtained for the low content of Hf. The obtained creep curves exhibit conventional shape： a short primary creep and long accelerated creep stages. The rupture properties of the heat-treated alloy follow the Monkman-Grant relationship, which exhibits similar creep behavior to that of NiAl/Cr（Mo） system with high Hf content.
基金National Natural Science Foundation of China(No.51371121).
文摘1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highest strength alloy to be developed as reported in recent researches[1-8].The tensile strength of this kind of alloy is usually around 2.0 GPa.The yield strength of a maraging steel re-cently fabricated by laser powder bed fusion can reach as high as about 2.4 GPa,but it is unfortunate that the elongation is merely about 1%[9].So it seems that 2.0 GPa yield strength is an upper limitation for this kind of alloy.To break through this limitation,it is of significance to establish a new composition design strat-egy.For instance,recent work[10]reported a medium Mn steel doped with Al and V elements,which exhibits an ultra-high yield strength of 2.21 GPa with 15%uniform elongation after thermo-mechanical processing.In another aspect,the design using multi-ple principal elements and additional elements to form a high en-tropy alloy(HEA)should be a very promising pathway.
基金Supported by the National Natural Science Foundation of China(Grant No.50771067)
文摘Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is employed to refine grain sizes to a nanoscale.Nanocrystalline AZ61 Mg alloy with an av-erage grain size of less than 100nm was successfully obtained using FSP.Corresponding to this,the highest microhardness of the nano-grained region reached triple times that of AZ61 substrate.In prin-ciple,by applying multiple overlapping passes,it should be possible to produce any desired size thin sheet of nanostructure using this technique.We expect that the FSP technique may pave a way to large-scale structural applications of nanostructured metals and alloys.
