Circuit and method for monitoring battery state of charge
AssigneeTexas Instruments Incorporated
InventorsEvgenij Barsoukov, Dan R. Poole, David L. Freeman
Life of this patent
Estimating the term…
Abstract
A processor (13) operates to determine amount of charge presently stored in a battery by determining that the battery is in a zero-current relaxed condition. Circuitry (16,23) including a first ADC (16) measures an open circuit voltage (OCV) of the battery prior to a period of time during which flow of current through the battery is not negligible. A program executed by the processor correlates the measured open circuit voltage (OCV0) with a corresponding value of the variable and selects the corresponding value as a value of the variable.
Claims38
A method of determining a value of a variable representing the amount of charge presently stored in a battery, comprising:
- (a) determining that the battery is in a zero-current relaxed condition by establishing that no more than a negligible amount of external current is flowing through the battery and that a sufficient amount of time has passed since a last significant current flow through the battery to ensure that the battery voltage is no longer significantly changing;
- (b) measuring an open circuit voltage (OCV) of the battery prior to a period of time during which flow of current through the battery is not negligible;
- and
- (c) using a predetermined dependence of the variable on the open circuit voltage of the battery to obtain a value of the variable which corresponds to the measured open circuit voltage.
A system for determining a value of variable representing the amount of charge presently stored in a battery, comprising:
- (a) a processor coupled to a digital bus, and a memory for storing data representing the relationship between the OCV (open circuit voltage) and DOD (depth of discharge) of the battery, a first ADC, and a second ADC all coupled to the digital bus;
- (b) a first program stored in the memory for execution by the processor for determining that the battery is in a zero-current relaxed condition by establishing that no more than a negligible amount of external current is flowing through the battery and that a sufficient amount of time has passed since a last significant current flow through the battery to ensure that the battery voltage is no longer significantly changing;
- (c) circuitry including the first ADC for measuring an open circuit voltage (OCV) of the battery prior to a period of time during which flow of current through the battery is not negligible;
- and
- (d) a second program stored in the memory for execution by the processor for correlating the measured open circuit voltage with a corresponding value of the variable and selecting the corresponding value as a value of the variable.
A system for determining a value of variable representing the amount of charge presently stored in a battery, comprising:
- (a) means for determining that the battery is in a zero-current relaxed condition by establishing that no more than a negligible amount of external current is flowing through the battery and that a sufficient amount of time has passed since a last significant current flow through the battery to ensure that the battery voltage is no longer significantly changing;
- (b) means for measuring an open circuit voltage (OCV) of the battery prior to a period of time during which flow of current through the battery is not negligible;
- (c) means for correlating the measured open circuit voltage with a corresponding value of the variable;
- and
- (d) means for selecting the corresponding value as the value of variable.
Dependencies are inferred from the claim text.