This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubat...This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.展开更多
Bent inlet pipes are often used in centrifugal compressors due to limited installation space,and an understanding of the effect on compressor stability is essential for safety and durability.This paper firstly investi...Bent inlet pipes are often used in centrifugal compressors due to limited installation space,and an understanding of the effect on compressor stability is essential for safety and durability.This paper firstly investigates flow instability behaviors in two compressors,one with a straight inlet pipe and the other with an S-shaped bent pipe.In detail,it analyzes the resulting flow fields,instability evolution paths and surge boundaries.The results show that the S-shaped pipe obviously affects the flow field at high mass flow rates,while reverse flow mainly influences the flow field at low mass flow rates.Reverse flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent pipe.In addition,centrifugal compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large size.Since the S-shaped pipe is not dominant in the creation and extension of reverse flow,it does not exacerbate the stability of the central compressor to a great extent.Last but not least,the S-shaped pipe is noted to delay the occurrence of surge at 90%rotating speed,which suggests the possibility of improving compressor stability with bent inlet pipes.This result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of centrifugal compressors.展开更多
Commercial polyolefin separators in lithium batteries encounter issues of uncontrolled lithium-dendrite growth and safety incidents due to their low Li+transference numbers(tLi+)and low melting points.To address these...Commercial polyolefin separators in lithium batteries encounter issues of uncontrolled lithium-dendrite growth and safety incidents due to their low Li+transference numbers(tLi+)and low melting points.To address these chal-lenges,this study proposes an innovative approach by upgrading conventional separators through the incorporation of metal-organic framework(MOF)-confined polyoxometalate(POM).The presence of POM restricts anion dif-fusion through electrostatic repulsion while facilitating Li+transport within MOF nanochannels through their affinity for lithium ions.Moreover,MOF confinement effectively mitigates the acidification of electrolytes induced by POM.As a proof-of-concept,the polypropylene separators decorated with phosphotungstic acid@UIO66(denoted as PW12@UIO66-PP)exhibit remarkable lithium-ion conductivity of 0.78 mS cm^(-1) with a high tLi+of 0.75 at room temperature.The modified separators also display excellent thermal stability,preventing significant shrinkage even at 150°C.Furthermore,Li symmetric cells employing PW12@UIO66-PP separators exhibit stable cycling for 1000 h,benefiting from rapid Li-ion transport and uniform deposition.Additionally,the modified separator shows promising adaptability to indus-trial manufacturing of lithium-ion batteries,as evidenced by the assembly of a 4 Ah NCM811/graphite pouch cell that retains 97%capacity after 350 cycles at C/3,thus highlighting its potential for practical applications.展开更多
Due to the favorable interfacial stability with electrodes,excellent processability,and reasonable material cost,organic-inorganic composite solid-state electrolytes have attracted broad interests in the field of soli...Due to the favorable interfacial stability with electrodes,excellent processability,and reasonable material cost,organic-inorganic composite solid-state electrolytes have attracted broad interests in the field of solid-state batteries.In this study,we have developed a solid-state composite electrolyte with polyurethane(PU)as polymer matrix and TiO_(2-x) as nanofiller(denoted as PUL-TiO_(2-x)).The block copolymer PU features alternating soft and hard segments,which offers distinct advantages due to its unique structural arrangement.The soft segment of the block copolymer facilitates the dissociation of lithium salt,enabling the conduction of Li^(+),while the rich hydrogen bond network formed by the hard segment ensures the mechanical strength of the electrolyte.The profusion of Lewis acid sites on the TiO_(2-x) surface facilitates interactions with ether oxygen groups and bistrifluoromethanesulfonimide(TFSI-)anions,thereby enhancing ionic conductivity(σ)and expanding the electrochemical stability window of the electrolyte.Notably,the PUL-TiO_(2-x) electrolyte exhibits an impressiveσof 2.19×10^(-4) S·cm^(-1) at 40℃,a Li^(+)transference number of 0.47,and an electrochemical stability window of 4.98 V.The resulting LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)||Li battery demonstrates a specific capacity of 171 mAh·g^(-1) and exhibits excellent cycling stability,maintaining its performance over 270 cycles at 40℃.These findings underscore the immense potential of the PUL-TiO_(2-x) in advancing the development of high-performance all-solid-state lithium batteries.展开更多
文摘This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.
基金co-supported by the Tsinghua University"Shuimu Tsinghua Scholar"Programthe National Science and Technology Major Project+2 种基金China(No.2017-II-0004-0016)the National Natural Science Foundation of China(No.51876097)the IHI Corporation,Yokohama,Japan。
文摘Bent inlet pipes are often used in centrifugal compressors due to limited installation space,and an understanding of the effect on compressor stability is essential for safety and durability.This paper firstly investigates flow instability behaviors in two compressors,one with a straight inlet pipe and the other with an S-shaped bent pipe.In detail,it analyzes the resulting flow fields,instability evolution paths and surge boundaries.The results show that the S-shaped pipe obviously affects the flow field at high mass flow rates,while reverse flow mainly influences the flow field at low mass flow rates.Reverse flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent pipe.In addition,centrifugal compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large size.Since the S-shaped pipe is not dominant in the creation and extension of reverse flow,it does not exacerbate the stability of the central compressor to a great extent.Last but not least,the S-shaped pipe is noted to delay the occurrence of surge at 90%rotating speed,which suggests the possibility of improving compressor stability with bent inlet pipes.This result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of centrifugal compressors.
基金supported by National Key R&D Program of China(2023YFB2503801)Key R&D Program of Hubei Province(2023BAB028)+2 种基金the National Natural Science Foundation of China(Grant Nos.52302253,and 5202780089)the Key Program of the National Natural Science Foundation of China(Grant No.52231009)the Fundamental Research Funds for the Central Universities(HUST:2172020kfyXJJS089).
文摘Commercial polyolefin separators in lithium batteries encounter issues of uncontrolled lithium-dendrite growth and safety incidents due to their low Li+transference numbers(tLi+)and low melting points.To address these chal-lenges,this study proposes an innovative approach by upgrading conventional separators through the incorporation of metal-organic framework(MOF)-confined polyoxometalate(POM).The presence of POM restricts anion dif-fusion through electrostatic repulsion while facilitating Li+transport within MOF nanochannels through their affinity for lithium ions.Moreover,MOF confinement effectively mitigates the acidification of electrolytes induced by POM.As a proof-of-concept,the polypropylene separators decorated with phosphotungstic acid@UIO66(denoted as PW12@UIO66-PP)exhibit remarkable lithium-ion conductivity of 0.78 mS cm^(-1) with a high tLi+of 0.75 at room temperature.The modified separators also display excellent thermal stability,preventing significant shrinkage even at 150°C.Furthermore,Li symmetric cells employing PW12@UIO66-PP separators exhibit stable cycling for 1000 h,benefiting from rapid Li-ion transport and uniform deposition.Additionally,the modified separator shows promising adaptability to indus-trial manufacturing of lithium-ion batteries,as evidenced by the assembly of a 4 Ah NCM811/graphite pouch cell that retains 97%capacity after 350 cycles at C/3,thus highlighting its potential for practical applications.
基金supported by the National Key R&D Program of China(No.2023YFB2503804)the National Natural Science Foundation of China(No.52202236)China Postdoctoral Science Foundation(Nos.2024T170300 and 2022M711232).
文摘Due to the favorable interfacial stability with electrodes,excellent processability,and reasonable material cost,organic-inorganic composite solid-state electrolytes have attracted broad interests in the field of solid-state batteries.In this study,we have developed a solid-state composite electrolyte with polyurethane(PU)as polymer matrix and TiO_(2-x) as nanofiller(denoted as PUL-TiO_(2-x)).The block copolymer PU features alternating soft and hard segments,which offers distinct advantages due to its unique structural arrangement.The soft segment of the block copolymer facilitates the dissociation of lithium salt,enabling the conduction of Li^(+),while the rich hydrogen bond network formed by the hard segment ensures the mechanical strength of the electrolyte.The profusion of Lewis acid sites on the TiO_(2-x) surface facilitates interactions with ether oxygen groups and bistrifluoromethanesulfonimide(TFSI-)anions,thereby enhancing ionic conductivity(σ)and expanding the electrochemical stability window of the electrolyte.Notably,the PUL-TiO_(2-x) electrolyte exhibits an impressiveσof 2.19×10^(-4) S·cm^(-1) at 40℃,a Li^(+)transference number of 0.47,and an electrochemical stability window of 4.98 V.The resulting LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)||Li battery demonstrates a specific capacity of 171 mAh·g^(-1) and exhibits excellent cycling stability,maintaining its performance over 270 cycles at 40℃.These findings underscore the immense potential of the PUL-TiO_(2-x) in advancing the development of high-performance all-solid-state lithium batteries.
