Method and circuit for determining battery capacity
AssigneeChristie Electric Corp.
InventorsFred Benjamin, Robert H. Heil
Life of this patent
Estimating the term…
Abstract
The capacity of a battery is determined while charging the battery by measuring the time it takes the battery voltage to decrease to a selected voltage level during discharging intervals interspersed between charging intervals. The state-of-charge is also determined by measuring the voltage level during a discharge interval while monitoring the duration of the charge cycle. Additionally, faulty cells of the battery are detected by measuring the voltage of the individual cells at the end of a discharging interval during the charging of the battery.
Claims11
A method of determining the capacity of a battery comprising the steps of:
- imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval;
- applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level;
- removing the load in response to the attainment of the selected level to end the discharge interval;
- and
- sensing the duration of each discharge interval as an indication of the capacity of the battery.
A method of determining the capacity of a battery comprising the steps of:
- imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval;
- applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level;
- removing the load in response to the attainment of the selected level to end the discharge interval;
- and
- measuring the cell trough voltage at the end of the battery discharge interval of each individual cell in succession.
A method of determining the capacity of a battery comprising the steps of:
- imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval;
- applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level;
- removing the load in response to the attainment of the selected level to end the discharge interval;
- applying a shunt in the path of the battery discharge current;
- developing a signal in response to the voltage across the shunt during each discharge interval with the signal having a duration determined by the duration of the discharge interval;
- and
- applying the signal to a bar chart display.
A battery charger analyzer comprising:
- a charge current source;
- means for applying a selected amplitude of charge current from the source to a battery for a selected interval of time;
- means for discharging the battery at the end of each charge current interval;
- means for sensing the battery terminal voltage during discharge;
- means responsive to the sensing means for terminating each discharge interval upon the battery terminal voltage decreasing to a selected level;
- means for sensing the duration of each discharge interval;
- and
- means for displaying this duration as a measure of the charge capacity of the battery.
Dependencies are inferred from the claim text.