The objective of this study was to determine THE THERMAL BEHAVIOR OF LITHIUM - ION PHOSPHATE ( LIFePo4 ) 20AH BATTERY by infrared thermograph . This study focused on the temperature distribution of the battery at day / night charging and discharging . The thermal gradient of battery ( LiFePo4 ) powered bike at different speed 30kmph , 40kmph , 50kmph both idle and load condition also evaluated The spatial distribution of LiFePo4 cells was not stable during the discharge process . At the end of the discharging , no crucial temperature rise was detected . The maximum temperature was recorded as 47.9 ° C , 33.8 ° C , and 44 ° C at 30kmph , idle run , charging at day respectively . Most of the maximum surface temperature was located at the lower part of the battery . The result shows thermal imaging is an effective tool to predict the temperature behavior of battery and provide a better thermal management system in E - bike battery development .