关键词: 锂离子电池, 低温性能, 电解质, 测试标准

Abstract:

Lithium-ion batteries (LIBs) have gradually extended to the field of low-temperature environment because of their advantages such as high energy density, long cycle life and no memory effect. However, LIBs suffer from rapid capacity decay and poor rate performance in low-temperature environment. Based on the discussion of the recent relevant literature, this paper makes a differentiation analysis of the existing LIBs test standards, focusing on the difference of different test standards on the low-temperature test conditions and technical requirements. The strategy of improving low-temperature performance of LIBs is introduced mainly from the Angle of electrolyte design and electrode material design. In the aspect of electrolyte design, the strategies of electrolyte additive design, co-solvent design, lithium salt modification design and lithium salt and solvent composite modification design are introduced. In the aspect of electrode material design, the strategies of nanization, doping, coating, doping/coating composite modification and heterojunction design are mainly introduced. The comprehensive analysis shows that, combined with the requirements of existing LIBs test standards, the strategy of electrolyte modification design combined with electrode material structure design is expected to overcome the problems such as fast capacity decay and poor rate performance of LIBs at low temperatures by improving the ionic conductivity of electrolyte and enhancing the charge transfer ability of electrode materials.

Key words: lithium-ion battery, low-temperature performance, electrolyte, testing standards