Reliable and timely detection of an internal short circuit(ISC)in lithium-ion batteries is important to ensure safe and efficient operation.This paper investigates ISC detection of parallel-connected battery cells by ...Reliable and timely detection of an internal short circuit(ISC)in lithium-ion batteries is important to ensure safe and efficient operation.This paper investigates ISC detection of parallel-connected battery cells by considering cell non-uniformity and sensor limitation(i.e.,no independent current sensors for individual cells in a parallel string).To characterize ISC-related signatures in battery string responses,an electro-thermal model of parallel-connected battery cells is first established that explicitly captures ISC.By analyzing the data generated from the electro-thermal model,the distribution of surface tem-perature among individual cells within the battery string is identified as an indicator for ISC detection under the constraints of sensor limitations.A convolutional neural network(CNN)is then designed to estimate the ISC resistance by using the cell surface temperature and the total capacity of the string as inputs.Based on the estimated ISC resistance from CNN,the strings are classified as faulty or non-faulty to guide the examination or replacement of the battery.The algorithm is evaluated in the presence of signal noises in terms of accuracy,false alarm rate,and missed detection rate,verifying the effectiveness and robustness of the proposed approach.展开更多
Absorption cooling technology is an environmentally friendly method to generate continuous chilled water making use of multiple thermal sources,such as waste heat and renewable thermal energy.In this study,two absorpt...Absorption cooling technology is an environmentally friendly method to generate continuous chilled water making use of multiple thermal sources,such as waste heat and renewable thermal energy.In this study,two absorption chillers(nominal capacity of 400 kW)with series and parallel connections are evaluated.To research the ideal configuration of chillers after thermodynamic analysis,the structures of the chillers are optimized using the particle swarm optimization algorithm by considering the heat transfer area(HTA),exergy efficiency and total annual cost as single-objective functions.The impact of temperature differences between external and internal flows,heat exchanger efficiencies and the solution allocation ratio is estimated.The optimized HTA,coefficient of perform-ance,exergy efficiency and total annual cost are 149.0 m^(2),1.56,29.44%and$229119 for the series-connected chiller,and 146.7 m^(2),1.59,31.45%and$234562 for the parallel-connected type,respectively.Under the lowest HTA condition,compared with the reference simulation results,the energy and exergy performances are improved,while the annual total cost is higher.The annual total cost is highest when maximizing the exergy efficiency,which is attributed to the increase in the HTA.The operating cost accounts for 27.42%(series type)and 26.54%(parallel type)when the annual cost is the lowest.展开更多
文摘Reliable and timely detection of an internal short circuit(ISC)in lithium-ion batteries is important to ensure safe and efficient operation.This paper investigates ISC detection of parallel-connected battery cells by considering cell non-uniformity and sensor limitation(i.e.,no independent current sensors for individual cells in a parallel string).To characterize ISC-related signatures in battery string responses,an electro-thermal model of parallel-connected battery cells is first established that explicitly captures ISC.By analyzing the data generated from the electro-thermal model,the distribution of surface tem-perature among individual cells within the battery string is identified as an indicator for ISC detection under the constraints of sensor limitations.A convolutional neural network(CNN)is then designed to estimate the ISC resistance by using the cell surface temperature and the total capacity of the string as inputs.Based on the estimated ISC resistance from CNN,the strings are classified as faulty or non-faulty to guide the examination or replacement of the battery.The algorithm is evaluated in the presence of signal noises in terms of accuracy,false alarm rate,and missed detection rate,verifying the effectiveness and robustness of the proposed approach.
基金supported by National Natural Science Foundation of China(grant no.51736006).
文摘Absorption cooling technology is an environmentally friendly method to generate continuous chilled water making use of multiple thermal sources,such as waste heat and renewable thermal energy.In this study,two absorption chillers(nominal capacity of 400 kW)with series and parallel connections are evaluated.To research the ideal configuration of chillers after thermodynamic analysis,the structures of the chillers are optimized using the particle swarm optimization algorithm by considering the heat transfer area(HTA),exergy efficiency and total annual cost as single-objective functions.The impact of temperature differences between external and internal flows,heat exchanger efficiencies and the solution allocation ratio is estimated.The optimized HTA,coefficient of perform-ance,exergy efficiency and total annual cost are 149.0 m^(2),1.56,29.44%and$229119 for the series-connected chiller,and 146.7 m^(2),1.59,31.45%and$234562 for the parallel-connected type,respectively.Under the lowest HTA condition,compared with the reference simulation results,the energy and exergy performances are improved,while the annual total cost is higher.The annual total cost is highest when maximizing the exergy efficiency,which is attributed to the increase in the HTA.The operating cost accounts for 27.42%(series type)and 26.54%(parallel type)when the annual cost is the lowest.
