Abstract: To evaluate the internal resistance characteristics of lithium iron phosphate batteries for automotive charging piles under different ambient temperatures, an analysis test was conducted. A 150 A·h single lithium iron phosphate battery cell for an automotive charging pile was selected as the research object. Power battery testing equipment and a constant temperature and humidity test chamber were used, and the hybrid pulse power characteristic (HPPC) method was applied. The test results show that during charging, at -20 ℃, the starting value of the ohmic internal resistance reaches 26 mΩ, the starting value of the polarization internal resistance is 4.4 mΩ, and the ohmic internal resistance accounts for 90% of the total internal resistance. At -10 ℃, the starting value of the ohmic internal resistance is 19 mΩ, the polarization internal resistance is 3.7 mΩ, and the proportion is 85%. At 0 ℃, the starting value of the ohmic internal resistance is 7 mΩ, the polarization internal resistance is 2.5 mΩ, and the proportion is 65%. At 15 ℃, the starting value of the ohmic internal resistance is 2.5 mΩ, the polarization internal resistance is 0.7 mΩ, and the proportion is 55%. At 40 ℃, the starting value of the ohmic internal resistance is 3 mΩ, the polarization internal resistance is 1.0 mΩ, and the proportion is 53% at the start and 70% at the end. During discharging, at -20 ℃, the starting value of the polarization internal resistance is 4.3 mΩ, and the ohmic internal resistance accounts for a high proportion and remains at a high level. At -10 ℃, the starting value of the polarization internal resistance is 2.9 mΩ, and the proportion fluctuates slightly. At 0 ℃, the starting value of the polarization internal resistance is 1.8 mΩ, and the proportion is moderate and stable. At 15 ℃, the starting value of the polarization internal resistance is 0.7 mΩ, and the proportion is moderate and stable. At 40 ℃, the starting value of the polarization internal resistance is 0.6 mΩ, and the proportion is the lowest at the start with a small increase.