Interactive battery charger for electric vehicle

1. A method for recharging an electric storage battery of a vehicle powered at least in part by electric energy from an electric utility power grid, the method comprising the steps of:

(a) determining a magnitude of electric energy required to recharge the battery to a desired state of charge;

(b) determining a maximum time rate at which the battery can be recharged; and

(c) using information from steps (a) and (b) to determine a length of time required to recharge the battery;

(d) determining a desired time when the recharge is to be completed;

(e) transmitting information from steps (c) and (d) to the electric power utility;

(f) recharging the battery from the utility grid during a period when projected load demand is lower than peak demand and ending no later than the desired time.

2. The method of claim 1 further comprising:

determining a projected load on the grid during a period ending at the desired time; and

determining a start time of the recharge from the projected load, the magnitude of electric energy required for the recharge, the length of time required to recharge the battery, and the desired time.

3. The method of claim 1 further comprising:

determining a projected load on the grid during a period ending at the desired time; and

determining a time rate of energy to be drawn from the grid during the recharge from the projected load, the magnitude of electric energy required for the recharge, the length of time required to recharge the battery and the desired time.

4. The method of claim 1 further comprises the steps of:

determining the user's cost for the planned recharge; and

transmitting from the electric power utility to the vehicle charging system the estimated cost for the recharge.

5. The method of claim 1 further comprises the steps of:

determining the start time of the recharge; and

transmitting from the electric power utility to the vehicle charging system the start time of the recharge.

6. The method of claim 1 further comprises the steps of:

determining the time rate of energy to be drawn from the grid during the recharge; and

transmitting from the electric power utility to the vehicle charging system a schedule of the electric charging rate for the recharge.

7. A system for recharging an electric storage battery of a vehicle powered at least in part by electric energy, comprising

an electric power utility that controls the supply of electric power;

a power grid on which electric power is transmitted;

a charger electrically connected to the power grid and the battery;

a controller electrically connected to the charger and the battery and communicating with the electric power utility, the controller determining the length of time required to recharge the battery, determining the desired time when the recharge is to be completed, transmitting to the electric utility the duration of the recharge and the desired time; determining a magnitude of electric energy required to recharge the battery to a desired state of charge; determining a maximum time rate at which the battery can be charged; using the magnitude of electric energy required to recharge the battery and the maximum time rate to calculate the length of time required to recharge the battery; and communicating to the electric rower utility the length of time required to recharge the battery.

8. The system of claim 7 wherein communications between the electric power utility and the controller are transmitted.

9. The system of claim 7 wherein the electric power utility further transmits to the controller the start time of the recharge.

10. A system for recharging an electric storage battery of a vehicle powered at least in part by electric energy, comprising

an electric power utility that controls the supply of electric power;

a power grid on which electric power is transmitted;

a charger electrically connected to the power grid and the battery;

a plug-in hybrid electric vehicle including a controller electrically connected to the charger and the battery and communicating with the electric power utility, the controller determining the length of time required to recharge the battery, determining the desired time when the recharge is to be completed, transmitting to the electric utility the duration of the recharge and the desired time, determining the magnitude of electric energy required to recharge the battery to a desired state of charge; determining the maximum time rate at which the battery can be charged; using the magnitude of electric energy required to recharge the battery and the maximum time rate to calculate the length of time required to recharge the battery; and communicating to the electric power utility the length of time required to recharge the battery.

11. The system of claim 10 wherein communications between the electric power utility and the controller are transmitted.

12. The system of claim 10 wherein the electric power utility further transmits to the controller the start time of the recharge.

13. A method for recharging an electric storage battery of a plug-in hybrid electric vehicle powered at least in part by electric energy from an electric utility power grid, the method comprising the steps of:

(a) determining a length of time required to recharge the battery;

(b) determining a desired time when the recharge is to be completed;

(c) transmitting information from steps (a) and (b) to the electric power utility; and

(d) recharging the battery from the utility grid during a period when projected load demand is lower than peak demand and ending no later than the desired time;

determining the time rate of energy to be drawn from the grid during the recharge; and

transmitting from the electric rower utility to the vehicle charging system a schedule of the electric charging rate for the recharge.

14. The method of claim 13 wherein step (a) further comprises the steps of:

determining the magnitude of electric energy required to recharge the battery to a desired state of charge;

determining the maximum time rate at which the battery can be recharged; and

using information from steps (e) and (f) to calculate said length of time required to recharge the battery.

15. The method of claim 13 further comprising:

determining a magnitude of electric energy required to recharge the battery to a desired state of charge;

determining a maximum time rate at which the battery can be recharged;

calculating a length of time required to recharge the battery;

determining a projected load on the grid during a period ending at the desired time; and

determining a start time of the recharge from the projected load, the magnitude of electric energy required for the recharge, the length of time required to recharge the battery, and the desired time.

16. The method of claim 13 further comprising:

calculating said length of time required to recharge the battery by determining a magnitude of electric energy required to recharge the battery to a desired state of charge and determining a maximum time rate at which the battery can be recharged;

determining a projected load on the grid during a period ending at the desired time; and

determining a time rate of energy to be drawn from the grid during the recharge from the projected load, the magnitude of electric energy required for the recharge, the length of time required to recharge the battery and the desired time.

17. The method of claim 13 further comprises the steps of:

determining the user's cost for the planned recharge; and

transmitting from the electric power utility to the vehicle charging system the estimated cost for the recharge.

18. The method of claim 13 further comprises the steps of:

determining the start time of the recharge; and

transmitting from the electric power utility to the vehicle charging system the start time of the recharge.