| 摘要 |
<p>A method of determining the state of charge of a rechargeable battery characterised by the steps of:
calculating the DC impedance of the battery by:
performing a first constant current discharge of the battery at a first C-rate; measuring the voltage and current during the interval of the first constant current discharge and calculating the amount of charge extracted from the battery up to a point i, whereby the battery voltage drops to a threshold value; calculating the state of charge as being equal to ((Qmax - Q i )lQ max )x 100, where Q max is the total charge extracted from the battery, and where Q i is the amount of charge extracted at the point I;
performing a second constant current discharge of the battery at a second C-rate lower than the first C-rate; measuring the voltage and current during the interval of the second constant current discharge and calculating the amount of charge extracted from the battery up to a point i, whereby the battery voltage drops to a threshold value; calculating the state of charge as being equal to (( Qmax - Q i / Q max ) x 100, where Q max is the total charge extracted from the battery, and where Q i is the amount of charge extracted at the point I; and
calculating the DC impedance of the battery, for a given state of charge as being: ( Vbat second C-rate - Vbat first C-rate )/( Iload first C-rate - Iload second C-rate ) , where
Vbat second C-rate and Vbat first C-rate are the battery voltages measured at the second C-rate and the first C-rate, respectively and where load second C-rate and Iload first C-rate are the current load when discharging at the second C-rate and the first C-rate, respectively.</p> |
