Lithium-ion batteries are used in a wide range of applications.However,their cycle life suffers from the problem of capacity fade,which includes calendar and cycle aging.The effects of storage time,temperature and par...Lithium-ion batteries are used in a wide range of applications.However,their cycle life suffers from the problem of capacity fade,which includes calendar and cycle aging.The effects of storage time,temperature and partial charge-discharge cycling on the capacity fade of Li-ion batteries are investigated in this study.The calendar aging and cycle aging are presented based on the storage and cycling experiment on LiCoO_(2)/graphite cells under different storage temperature and different ranges of state of charge(SOC).Based on the measurement data,a one-component and a double-component aging model are presented to respectively describe the capacity fade caused by calendar and cycle aging.The calendar aging of LiCoO_(2)/graphite batteries is mainly affected by temperature and SOC during the storage.Mean SOC and change in SOC(ΔSOC)are the main factors affecting battery degradation during cycling operation.展开更多
LCO_2(liquid CO_2) can absorb heat and release latent heat via phase transition, which can provide considerable cooling energy and effectively solve the problem of thermal damage in deep coal mining processes. A LCO_2...LCO_2(liquid CO_2) can absorb heat and release latent heat via phase transition, which can provide considerable cooling energy and effectively solve the problem of thermal damage in deep coal mining processes. A LCO_2 cycle refrigeration system is designed to continuously cool down the working face in a mine, and CO_2 is cyclically utilized. Additionally, LCO_2 is used not only as a cold source but also to prevent spontaneous combustion of coal in the gob. COMSOL Multiphysics simulation software is used to characterize the thermal performance of the heat exchange system, where the heat transfers between the CO_2 and the airflow. For a LCO_2 consumption of 13.54 m^3/h, the temperature of the airflow in the tunnel decreases by 7.72°C, and the cooling volume of the system reaches 142.99 kW/h; the cooling volume provides a latent heat release of 46.68 k W/h. The main influencing factors of the refrigeration system, such as ventilation flux, LCO_2 flow, LCO_2 temperature and initial tunnel temperature, are also analyzed quantitatively through the software. The temperature of the steady airflow in the tunnel is proportional to the square of the local fan ventilation flux, and it decreases linearly with an increase in the LCO_2 flow but increases with both the temperature of the LCO_2 and the initial temperature in the tunnel. When the temperature difference between the LCO_2 and wind increases, the heat exchange between the CO_2 and wind intensifies, and the cooling volume increases.展开更多
基金supported by Shandong University Seed Fund Program for International Research Cooperation。
文摘Lithium-ion batteries are used in a wide range of applications.However,their cycle life suffers from the problem of capacity fade,which includes calendar and cycle aging.The effects of storage time,temperature and partial charge-discharge cycling on the capacity fade of Li-ion batteries are investigated in this study.The calendar aging and cycle aging are presented based on the storage and cycling experiment on LiCoO_(2)/graphite cells under different storage temperature and different ranges of state of charge(SOC).Based on the measurement data,a one-component and a double-component aging model are presented to respectively describe the capacity fade caused by calendar and cycle aging.The calendar aging of LiCoO_(2)/graphite batteries is mainly affected by temperature and SOC during the storage.Mean SOC and change in SOC(ΔSOC)are the main factors affecting battery degradation during cycling operation.
基金financial support from the Key R & D Project in Shaanxi Province (2018KW-035)Scientific Research Plan Projects of Shaanxi Provincial Department of Education (18JK0515)National Natural Science Foundation of China (Grant No. 51804245)
文摘LCO_2(liquid CO_2) can absorb heat and release latent heat via phase transition, which can provide considerable cooling energy and effectively solve the problem of thermal damage in deep coal mining processes. A LCO_2 cycle refrigeration system is designed to continuously cool down the working face in a mine, and CO_2 is cyclically utilized. Additionally, LCO_2 is used not only as a cold source but also to prevent spontaneous combustion of coal in the gob. COMSOL Multiphysics simulation software is used to characterize the thermal performance of the heat exchange system, where the heat transfers between the CO_2 and the airflow. For a LCO_2 consumption of 13.54 m^3/h, the temperature of the airflow in the tunnel decreases by 7.72°C, and the cooling volume of the system reaches 142.99 kW/h; the cooling volume provides a latent heat release of 46.68 k W/h. The main influencing factors of the refrigeration system, such as ventilation flux, LCO_2 flow, LCO_2 temperature and initial tunnel temperature, are also analyzed quantitatively through the software. The temperature of the steady airflow in the tunnel is proportional to the square of the local fan ventilation flux, and it decreases linearly with an increase in the LCO_2 flow but increases with both the temperature of the LCO_2 and the initial temperature in the tunnel. When the temperature difference between the LCO_2 and wind increases, the heat exchange between the CO_2 and wind intensifies, and the cooling volume increases.
