ESTIMATION METHOD FOR STATE OF CHARGE OF LITHIUM IRON PHOSPHATE POWER BATTERY PACKS

摘要

An estimation method for SOC of lithium iron phosphate power battery packs, include: 1, selecting a secondary battery (A) having characteristics of linear relationship between terminal voltage and SOC1; 2, connecting the secondary battery (A) with lithium iron phosphate power battery packs (B) in series, 3, repeatedly detecting values of the SOC1 and values the terminal voltages Ua of the secondary battery during the secondary battery is charging or discharging, fitting a formula (1) between the SOC1 and the terminal voltage Ua, the formula (1) being shown as following: SOC1=K1*Ua+M1 (1); 4, obtaining a formula (2) between SOC1 and SOC of the lithium iron phosphate power battery pack: SOC1=K2*SOC+M2 (2); 5, by formula (1) and formula (2), obtaining a formula (3) for calculating the SOC of the lithium iron phosphate power battery pack, the formula (3) being shown as following: SOC=Ua*K1/K2+(M1-M2)/K2 (3).