Method for estimating state of charge for lithium-ion batteries

摘要

A state of charge (SoC) a lithium-ion (Li+) battery is estimated at a time instant by first constructing a battery model of the Li+ battery based on a single particle operation. The battery model describes a relationship between the SoC, a charge current, a discharge current, and an output voltage of the Li+ battery. Using a nonlinear optimization, a function expressing a relationship between the SoC and an open circuit voltage of the Li+ battery is determined. The relationship is based on off-line measurements of the charge current, the discharge current, and the open-circuit voltage of the Li+ battery. Then, the SoC and parameters of the battery model are estimated concurrently, wherein the SoC and the parameters are estimated based on the battery model, the function, and on-line measurements of the charge current, the discharge current, and the output voltage.

主权项

1. A method for estimating a state of charge (SoC) a lithium-ion (Li+) battery at a time instant, comprising steps of:
measuring a charge current, a discharge current, an open circuit voltage (OCV), and an output voltage during an off-line operation of the Li+ battery; constructing a battery model of the Li+ battery, wherein the battery model is constructed based on a single particle operation of the Li+ battery, where the battery model describes a relationship between the SoC, the charge current, the discharge current; determining, using a nonlinear optimization, a function expressing a relationship between the SoC and the OCV of the Li+ battery, wherein the relationship is based on off-line measurements of the measuring the charge current, the discharge current, and the OCV; and estimating the SoC and parameters of the battery model concurrently, wherein the SoC and the parameters are estimated based on the battery model, the function, and on-line measurements of the charge current, the discharge current, and the OCV, wherein the steps are performed in a processor connected to the Li+ battery.