Self-correction method for remaining capacity estimation of lithium iron phosphate power battery

Abstract

The invention discloses a self-correction method for remaining capacity estimation of a lithium iron phosphate power battery. The conventional method cannot meet national standard well. According to the self-correction method disclosed by the invention, compensation and correction are performed on the basis of estimating the remaining capacity of the lithium iron phosphate power battery by using an ampere-hour method; and according to the characteristic that voltage of the lithium iron phosphate power battery abruptly changes at the end stage of charging or discharging, the actual remaining capacity SOC (State Of Charge) is corrected when dV / dSOC' is detected to be greater than or equal to 0.05, so that accumulative estimation error existing during independent use of the ampere-hour method is reduced. The self-correction method is based on the ampere-hour method, is simple and easy and is easier to apply and generalize. Meanwhile, the invention also provides a calculation method of aging rate gamma. By continuously updating the aging rate, the error for estimation by using the ampere-hour method is reduced again.

Description

technical field [0001] The invention belongs to the technical field of chemical energy application, and in particular relates to a method for estimating and self-correcting the remaining capacity of a lithium iron phosphate power battery. Background technique [0002] With the enhancement of global environmental awareness and the prominence of energy issues, electric vehicles have become the most important development direction of green vehicles. At present, the power batteries used in electric vehicles mainly include lead-acid batteries, nickel-metal hydride batteries and lithium-ion batteries, each with its own advantages and disadvantages. Lithium iron phosphate power battery has the advantages of long life, safe use, fast charging and discharging with high current, high temperature resistance, large capacity, and no memory effect, which can better meet the requirements of electric vehicles for on-board batteries, and has been rapidly applied and promoted. . [0003] Th...

AI Technical Summary

Problems solved by technology

[0008] The Kalman filter method is an optimal estimate of the state of the dynamical system in the sense of minimum variance, but this method requires a large amount of calculation

[0009] Since the lithium iron phosphate power battery has a very flat charging and discharging platform, and the SOC of the battery management system needs to be high-precision and real-time online estimation, then the remaining capacity calculation method related to the open circuit voltage method is no longer applicable to lithium iron phosphate Power Battery

The control strategy of electric vehicles is adjusted at any time according to the SOC of the battery pack, and the current SOC value must be provided accurately at any time, which requires that there should be no cumulative error. The current national standard requires that the error should not exceed 8%, while the existing Technical estimation methods are not easy to satisfy

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