Performance Degradation Prediction and Cell Balance Control Algorithm Construction of Lithium Iron Phosphate Battery

Abstract

Various studies were conducted from the aspects of both the battery cells and the module with the aim of making more effective use of the battery capacity. As a result, after 77 cycles of driving and rapid charging, the capacity degradation of the battery module as a whole was 7.7 % and it was determined that the cause of this additional 0.7 % degradation of the capacity was the loss of cell balance. In addition, by adopting module balance coefficient (945;) that was proposed as an indicator to show the available percentage of the lowest capacity cell in the module, new cell balancing rules were created that do not significantly affect the convenience of vehicle operation.