Effect of anode binders on low-temperature performance of automotive lithium-ion batteries

摘要

The effect of styrene-butadiene rubber (SBR)/sodium salt of carboxymethyl cellulose (CMC) and poly(vinylidene fluoride) (PVdF) binders in the anodes on low-temperature performance and cyclability of automotive Li-ion batteries is investigated in 2.0 Ah cylindrical 18650 cells, composed of LiNi0.5Co0.2Mn0.3O2 as cathodes and graphite as anodes. The physical and electrochemical properties of SBR/CMC and PVdF anodes are characterized to compare their low-temperature performance. It is found that the adhesion strength of the SBR/CMC anode is slightly higher than that of the PVdF anode. On the other hand, because of its lower glass transition temperature (T-g), higher ionic conductivity and better absorption of the electrolyte, the PVdF anode results in higher electrical and ionic conductivity than observed in the SBR/CMC anode at low temperatures. These properties of the PVdF anode contribute to smaller impedance and faster Li-ion diffusion. Thus, the PVdF anode exhibits better discharge behavior and cycle performance at low temperatures than the SBR/CMC anode.