Battery power management in hybrid vehicles

1. A vehicle comprising:

a traction battery; and

a controller programmed to charge and discharge the battery according to an upper power limit conditioned via a PID controller configured to remove perturbations therefrom that is based on estimates of ion-concentration profiles of the battery such that for a given state of charge and temperature of the battery, the upper power limit decreases as the profiles become less-linear.

2. The vehicle of claim 1 , wherein the upper power limit is further based on a difference between a predefined expected power capability limit at the given state of charge and a power capability limit estimated from a voltage output and current input associated with the given state of charge.

3. The vehicle of claim 2 , wherein the predefined expected power capability limit is output from a steady-state power capability map.

4. The vehicle of claim 2 , wherein the power capability limit estimated from the voltage output and current input is output from a real-time power capability estimator.

5. The vehicle of claim 1 , wherein the PID controller has non-zero proportional and derivative gain.

6. A controller comprising:

input channels configured to receive voltage output and current input data associated with a given state of charge of a battery;

output channels configured to provide a power limit for the battery; and

control logic programmed to generate the power limit based on estimates of ion-concentration profiles derived from the data such that for a given state of charge and temperature of the battery, the power limit decreases as the profiles become less-linear.

7. The controller of claim 6 , wherein the power limit is further based on a difference between a predefined expected power capability limit at the given state of charge and a power capability limit estimated from the data.

8. The controller of claim 7 , wherein the predefined expected power capability limit is output from a steady-state power capability map.

9. The controller of claim 7 , wherein the power capability limit estimated from the data is output from a real-time power capability estimator.

10. The controller of claim 6 , wherein the power limit is conditioned via a transfer function configured to remove perturbations therefrom.

11. The controller of claim 10 , wherein the transfer function is a PID controller.

12. The controller of claim 11 , wherein the PID controller has a non-zero proportional and derivative gain.

13. A vehicle power system comprising:

a controller programmed to charge and discharge a battery according to an upper power limit that is based on

estimates of ion-concentration profiles of the battery such that for a given battery state of charge, the upper power limit decreases as the profiles become less-linear, and

a difference between a predefined expected power capability limit and a power capability limit estimated from a voltage output and current input.

14. The vehicle power system of claim 13 , wherein the predefined expected power capability limit is output from a steady-state power capability map.

15. The vehicle power system of claim 13 , wherein the power capability limit estimated from the voltage output and current input is output from a real-time power capability estimator.

16. The vehicle power system of claim 13 , wherein the upper power limit is conditioned via a transfer function configured to remove perturbations therefrom.

17. The vehicle power system of claim 16 , wherein the transfer function is a PID controller.

18. The vehicle power system of claim 16 , wherein the PID controller has non-zero proportional and derivative gain.