Battery capacity estimation using state of charge initialization-on-the-fly concept
AssigneeFord Global Technologies, LLC
InventorYonghua Li
Life of this patent
Estimating the term…
Abstract
Hybrid-electric and pure electric vehicles include a traction battery comprised of many cells. Controlling a battery system may require that a battery state of charge and a battery capacity be known. The state of charge and battery capacity values may be derived from estimated traction battery model parameters. The accuracy of the estimated model parameters depends on the signal richness and convergence properties of the estimation scheme. Accurate model parameters may be estimated when a persistent excitation condition and an estimation convergence condition are met. If the conditions are not met, active excitation of the battery may be performed to improve the chances of meeting the conditions.
Claims20
A battery control system for a vehicle comprising:
- a traction battery including a plurality of cells;
- and
- at least one controller programmed to generate open-loop and closed-loop model parameter estimates for the traction battery and, in response to detecting that a persistent excitation condition and an estimation convergence condition are satisfied, change from operating the traction battery according to an open-loop estimate derived state of charge to a closed-loop estimate derived state of charge.
A vehicle comprising:
- a traction battery including a plurality of cells;
- and
- at least one controller programmed to generate model parameter estimates for the traction battery and, in response to a persistent excitation condition not being satisfied, vary a battery power demand to cause a predetermined number of frequency component amplitudes of the battery power demand to exceed a predetermined magnitude without affecting acceleration of the vehicle.
A method of operating a traction battery comprising:
- scheduling a time window in which to learn a battery capacity;
- in response to a persistent excitation condition and an estimation convergence condition being satisfied during the window, learning a first state of charge value and, after the battery experiences a predetermined amount of current throughput, learning a second state of charge value;
- and
- operating the traction battery according to the battery capacity derived from the values.
Dependencies are inferred from the claim text.