Method for estimating remaining capacity of battery

• US 20090254290A1
• Filed: 08/29/2008
• Published: 10/08/2009
• Est. Priority Date: 04/03/2008
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Inventors: Kim, Woo Sung, Hwang, Do Sung, Cho, Il
• Granted Patent: US 8,589,096 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a method for estimating a remaining capacity of a battery. The method comprises: measuring a current value, a voltage value and temperature of the battery; correcting the current value based on the voltage value; calculating a current integration value by integrating the corrected current value and calculating a current integration capacity from the calculated current integration value by reflecting a charge/discharge efficiency; determining a battery forward voltage capacity from the measured current value, voltage value and temperature, and determining whether it is necessary to correct the current integration capacity based on the forward voltage capacity; converting the current integration capacity into a remaining capacity, if it is determined that it is not necessary to correct; and correcting, if it is determined that it is necessary to correct, the current integration capacity and converting the corrected current integration capacity into a remaining capacity. With the method, SOC of the battery can be more accurately calculated.

Claims

1. A method for estimating a remaining capacity of a battery, the method comprising:

measuring a current value, a voltage value and temperature of the battery;

correcting the current value based on the voltage value;

calculating a current integration value by integrating the corrected current value and calculating a current integration capacity from the calculated current integration value by reflecting a charge/discharge efficiency;

determining a battery forward voltage capacity from the measured current value, voltage value and temperature, and determining whether it is necessary to correct the current integration capacity based on the forward voltage capacity;

converting the current integration capacity into a remaining capacity, if it is determined that it is not necessary to correct; and

correcting, if it is determined that it is necessary to correct, the current integration capacity and converting the corrected current integration capacity into a remaining capacity.

2. The method of claim 1, wherein the correction of the current value based on the voltage value comprises obtaining a change in current due to a change in voltage from a battery characteristic table, which has been data processed, and correcting the current value using a correction amount determined from the change in current.

3. The method of claim 1, wherein the determination of whether it is necessary to correct the current integration capacity comprises:

calculating a battery forward voltage based on the measured current value, voltage value, and temperature;

determining, based on the calculated forward voltage, a forward voltage capacity from a forward voltage-capacity map table;

comparing a deviation between the calculated current integration capacity and the forward voltage capacity with a predetermined reference value; and

determining that it is necessary to correct the current integration capacity, if the deviation exceeds the reference value.

4. The method of claim 1, wherein the current integration capacity is corrected using an error rate of the forward voltage calculation, a current integration value error rate corresponding to the deviation between the calculated current integration capacity and the forward voltage capacity, and a predetermined reference error rate.

5. The method of claim 4, wherein the error rate of the forward voltage calculation is obtained from a table defined as a value according to a battery temperature/forward voltage error rate obtained by an actual vehicle test.