Effect of Binder on Internal Resistance and Performance of Lithium Iron Phosphate Batteries

Abstract

In this paper, a water-based binder was prepared by blending polyacrylic acid (PAA) and polyvinyl alcohol (PVA). The effects of the binder on the internal resistance and electrochemical performance of lithium iron phosphate batteries were analyzed by comparing it with LA133 water binder and PVDF (polyvinylidene fluoride). First, positive electrode sheets were prepared by using PVDF, PAA/PVA and LA133 as binders, respectively. and the effects of binders on the resistivity and compaction density of electrode sheets were analyzed. Secondly, the buckle battery and the 14500 steel shell full battery were prepared by using PVDF, PAA/PVA and LA133 as binders, respectively. The influence of the positive electrode materials prepared by different binders on the internal resistance of the battery and on the charge and discharge performance and cycle performance of the battery was analyzed. The results show that the internal resistance test of 14500 type whole cell prepared with PVDF, PAA/PVA and LA133 as the binder shows that the internal resistance of sample batteries LFP-F, LFP-AV and LFP-L are 40.5 mΩ, 33.2 mΩ and 35.7 mΩ, respectively. The internal resistance of the battery prepared by self-made PAA/PVA binder is the lowest.