Battery charging based on cost and life

• US 7,782,021 B2
• Filed: 07/18/2007
• Issued: 08/24/2010
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Berdichevsky, Eugene Michael, Kelty, Kurt Russell
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): RAMADAN, RAMY O
• Application Number:
  US11/779,837
• Publication Number:
  US 20090021218A1
• Time in Patent Office: 1,133 Days
• Field of Search: 320/109, 320/155
• US Class Current: 320/155
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/64 Optimising energy costs, e.g. responding to electricity rates
• CPC Class Codes: B60L 55/00 Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: G06Q 30/0284 Time or distance, e.g. usage of parking meters or taximeters
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 30/14 Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing
• CPC Class Codes: Y04S 50/14 Marketing, i.e. market research and analysis, surveying, promotions, advertising, buyer profiling, customer management or rewards

Abstract

One embodiment of the present subject matter includes a system that includes a battery, an electric vehicle, the battery coupled to the electric vehicle to propel the electric vehicle, and a charging circuit to charge the battery. The embodiment includes a charging cost circuit to estimate a charging cost rate and to turn on the charging circuit. The embodiment also includes a timer circuit to provide a time signal to the charging cost circuit. The embodiment is configured such that the charging cost circuit is to turn on the charging circuit during a first time period in which the charging cost rate is below a first threshold until the battery reaches a first energy stored level, and to turn on the charging circuit during a second time period in which the charging cost rate is above the first threshold.

Claims

1. A method of charging a battery within an electric vehicle utilizing a battery charging system, the method comprising the steps of:

continuously determining an instantaneous charging cost rate, wherein said instantaneous charging cost rate is continuously determined as a function of time;

determining a charging schedule that includes at least a first time period and a second time period, wherein said first time period precedes said second time period, and wherein a charging stop time is anticipated to occur within said second time period;

initiating battery charging within said first time period whenever said instantaneous charging cost rate is less than a threshold cost rate;

pausing battery charging within said first time period whenever said instantaneous charging cost rate is greater than said threshold cost rate;

resuming battery charging within said first time period whenever said instantaneous charging cost rate is less than said threshold cost rate;

terminating battery charging within said first time period after said battery reaches a first energy stored level;

initiating battery charging within said second time period regardless of said instantaneous charging cost rate; and

terminating battery charging within said second time period after said battery reaches a second energy stored level, wherein the second energy stored level is higher than the first energy stored level.

2. The method of claim 1, wherein the second energy stored level is less than a full energy stored level.

3. The method of claim 1, wherein said step of initiating battery charging within said second time period is only performed in response to a stored indicator.

4. The method of claim 1, further comprising:

predicting a daily cost based on an energy usage pattern; and

adjusting the length of the first time period and length of the second time period to minimize the predicted daily cost.

5. The method of claim 1, further comprising:

predicting said charge stop time based on an energy usage pattern; and

determining a start time for performing said step of initiating battery charging within said second time period, wherein said start time is selected to allow said second energy stored level to be reached prior to occurrence of said charging stop time.

6. The method of claim 5, wherein no charging occurs during at least a portion of the second time period.

7. The method of claim 1, wherein said step of continuously determining said instantaneous charging cost rate further comprises the step of receiving charging cost rate from a municipal power grid.

8. The method of claim 1, further comprising the steps of programming said charging stop time within said battery charging system and determining a start time for performing said step of initiating battery charging within said second time period, wherein said start time is selected to allow the second energy stored level to be reached before the charge stop time.

9. The method of claim 1, further comprising the steps of:

monitoring a daily charging system termination time; and

estimating said charging stop time based on results of said monitoring step; and

determining a start time for performing said step of initiating battery charging within said second time period, wherein said start time is selected to allow the second energy stored level to be reached prior to occurrence of said charging stop time.

10. The method of claim 1, further comprising the step of setting said second energy stored level to 100% energy capacity.

11. The method of claim 1, further comprising the steps of monitoring a plurality of charge cycles, and increasing said second energy stored level based on results of said monitoring step.

12. The method of claim 11, wherein said monitoring step further comprises the step of monitoring driving range over time and wherein said step of increasing said second energy stored level further comprises setting said second energy stored level to maintain a predetermined driving range.

13. A battery charging system, comprising:

a battery;

an electric vehicle, the battery coupled to a propulsion motor configured to propel the electric vehicle;

a charging circuit to charge the battery;

a timer circuit outputting a plurality of timing signals corresponding to at least a first time period and a second time period, wherein said first time period precedes said second time period;

a charging cost circuit, wherein said charging cost circuit controls operation of said charging circuit and receives said plurality of timing signals from said timer circuit, wherein said charging cost circuit continuously monitors an instantaneous charging cost rate, wherein said charging cost circuit initiates operation of said charging circuit during said first time period whenever said instantaneous charging cost rate is below a threshold cost rate, pauses operation of said charging circuit during said first time period whenever said instantaneous charging cost rate is above said threshold cost rate, resumes operation of said battery charging circuit during said first time period whenever said instantaneous charging cost rate is less than said threshold cost rate and terminates operation of said charging circuit during said first time period when said battery reaches a first energy stored level, and wherein said charging cost circuit initiates operation of said charging circuit during said second time period regardless of said instantaneous charging cost rate and continues operation of said charging circuit until said battery reaches a second energy stored level or operation is disrupted by a system user, wherein said second energy stored level is greater than said first energy stored level.

14. The battery charging system of claim 13, further comprising a trend circuit to monitor a plurality of daily charging system termination times, said trend circuit determining a charging stop time based on said plurality of daily charging system termination times, wherein the charging cost circuit determines a charging circuit initiation time within said second time period to achieve said second energy stored level prior to reaching said charging stop time.

15. The battery charging system of claim 13, further comprising a user controllable interface connected to said charging cost circuit such that a user can input said threshold cost rate.

16. The battery charging system of claim 13, further comprising a user controllable interface connected to said charging cost circuit such that a user can input a charging stop time, wherein the charging cost circuit automatically selects a charging circuit initiation time within said second time period to achieve said second energy stored level prior to reaching said charging stop time.

17. The battery charging system of claim 13, wherein said second energy stored level is less than a full energy stored level.

18. The battery charging system of claim 13, further comprising a user controllable interface connected to the charging cost circuit such that a user can input a charging circuit initiation time within said second time period.

19. The battery charging system of claim 13, further comprising a user controllable interface connected to the charging cost circuit such that a user can input a length of time for said first time period.

20. The battery charging system of claim 13, wherein said first energy stored level is 80% of full stored energy.

21. The battery charging system of claim 13, wherein said second energy stored level is 90% of full stored energy.

22. The battery charging system of claim 13, wherein said charging cost circuit receives a municipal charging cost rate from a power network and estimates said instantaneous charging cost rate based on said municipal charging cost rate.