System and method for battery-electric vehicle fleet charging

1. A fleet charging system comprising:

a plurality of chargers; and

a controller programmed to predict charge demand and charge time intervals for fleet and nonfleet vehicles, charge fleet vehicles to store energy for sale that exceeds a predicted energy usage for a drive cycle, and discharge the fleet vehicles to satisfy charge demand for nonfleet vehicles to minimize a difference between the energy stored for sale and energy delivered to the nonfleet vehicles.

2. The fleet charging system of claim 1 , wherein the controller is further programmed to throttle a charging rate of the nonfleet vehicles to minimize a difference between energy stored in the fleet vehicles and actual energy delivered.

3. The fleet charging system of claim 1 , wherein the controller is further programmed to receive a reservation request for charging from the nonfleet vehicles.

4. The fleet charging system of claim 3 , wherein the controller is further programmed to provide an incentive to the nonfleet vehicles for providing a reservation request.

5. The fleet charging system of claim 4 , wherein the incentive is a discounted price for electricity provided to the nonfleet vehicle.

6. A method comprising:

by a controller,

receiving a reservation request for the nonfleet vehicle that includes predicted charge demand and charge time interval for the nonfleet vehicle;

predicting energy demand and charge time intervals for fleet and nonfleet vehicles at a charging facility including a plurality of chargers;

charging fleet vehicles, that are predicted to be coupled to the chargers when a nonfleet vehicle is predicted to be charging according to the predicted charge time intervals, to a level exceeding the predicted energy demand of the fleet vehicles by an amount that is defined by the predicted energy demand for the nonfleet vehicle; and

discharging the fleet vehicles to charge the nonfleet vehicle when connected.

7. The method of claim 6 further comprising charging the fleet vehicles at a time when a cost of electricity from an electrical supplier is less than a cost of electricity when the nonfleet vehicle is predicted to be charging.

8. The method of claim 7 further comprising setting a price for energy provided to the nonfleet vehicle that exceeds an amount paid for the energy.

9. The method of claim 6 further comprising providing an incentive for nonfleet vehicles to permit throttling of a charging rate to minimize a difference between energy stored in fleet vehicles and energy delivered to the nonfleet vehicle.

10. The method of claim 6 further comprising minimizing a charging cost for fleet vehicles.

11. The method of claim 6 further comprising storing energy in fleet vehicles during periods of minimum electricity cost during a predetermined time period and transferring the energy between fleet vehicles during periods at which the electricity cost is greater than the minimum electricity cost.

12. The method of claim 6 further comprising generating and evaluating fleet schedules to minimize energy usage of the fleet vehicles.

13. A fleet charging system comprising:

a plurality of chargers; and

a controller programmed to predict charge demand for fleet and nonfleet vehicles over a predetermined time interval, generate a charge strategy for the predetermined time interval that minimizes a total energy cost and includes storing energy in the fleet vehicles for sale to the nonfleet vehicles, and charge and discharge the fleet and nonfleet vehicles according to the charge strategy, wherein the controller is further programmed to discharge the fleet vehicles to supply energy to the nonfleet vehicles such that the fleet vehicles retain a charge corresponding to a predicted energy usage for each of the fleet vehicles.

14. The fleet charging system of claim 13 , wherein the charge strategy includes charging the fleet vehicles at a time when a cost of electricity from an electrical supplier is minimum.

15. The fleet charging system of claim 13 , wherein the controller is further programmed to receive a reservation request for the nonfleet vehicles.

16. The fleet charging system of claim 13 , wherein the controller is further programmed to provide an incentive for nonfleet vehicles that permit throttling of a charging rate to minimize a difference between energy stored in fleet vehicles and energy delivered to nonfleet vehicles.

17. The fleet charging system of claim 13 , wherein the controller is further programmed to implement a dynamic programming algorithm to minimize the total energy cost for the fleet vehicles.

18. The fleet charging system of claim 13 , wherein the controller is further programmed to charge and discharge the fleet vehicles such that an amount of energy stored in each is at least an amount of energy required to complete an upcoming route.