期刊
JOURNAL OF POWER SOURCES
卷 117, 期 1-2, 页码 170-178出版社
ELSEVIER
DOI: 10.1016/S0378-7753(03)00354-9
关键词
discharge capability; limiting factor; Li-ion cell
We here study the discharge capability of commercial 18650 cylindrical lithium-ion cells at low temperatures. The discharge capacity at -20 degreesC ranges from 67 to 88% of the rated capacity at 0.2C rate, which is good. However, the cell discharge capacity varies substantially at -30 and -40 degreesC among the studied cells. It ranges from 2 to 70% of the rated capacity at -30 degreesC, and 0 to 30% at -40 degreesC at 0.2C rate. The cell impedance at I kHz increases very little from room temperature down to -20 or -30 degreesC in general, which does not correlate with the cell discharge capability. However, the dc impedance is increased by a factor of about ten at -30 degreesC and about twenty at -40 degreesC from room temperature. The discharge capability at low temperature correlates well with the dc resistance at both room and low temperatures. The limiting factors in the discharge capability at low temperatures and the direction for the future improvement are discussed according to the cell discharge capability, the electrode geometric area, the cell impedance at I kHz, and the dc impedance at various temperatures. It appears that the ionic conductivity of the electrolyte and lithium solid diffusion in the electrode do not limit the cell discharge capability, while the lithium diffusion in the SEI layer on the positive surface may be the limiting factor. Cell discharge capability at low temperature does not correlate with cycle life at room temperature. (C) 2003 Elsevier Science B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据