Charge management for energy storage temperature control

• US 9,007,027 B2
• Filed: 01/31/2012
• Issued: 04/14/2015
• Est. Priority Date: 01/31/2012
• Status: Active Grant

• Current Assignee: Engie Storage Services NA LLC (ENGIE SA)
• Original Assignee: Green Charge Networks LLC (ENGIE SA)
• Inventors: Prosser, Ronald D
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US13/362,157
• Publication Number:
  US 20130193928A1
• Time in Patent Office: 1,169 Days
• Field of Search: 320/130, 320/144, 320/153, 320/154, 320/166, 320/167, 320/150, 320/103, 429/120, 429/134, 429/433, 429/441, 429/442, 429/61, 429/62
• US Class Current: 320/130
• CPC Class Codes: H02J 7/00041 in response to measured battery parameters, e.g. voltage, current or temperature profile
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

Charging and discharging an energy storage device (ESD) generates heat and may prevent its temperature from dropping to unsafe levels. By monitoring and managing the charge and discharge of an ESD with respect to the periods of time in which demand charges are determined, the heating will have minimal adverse effect on demand charges. ESDs may also exchange energy in a controlled manner for heating purposes and reduce reliance on utility grid-based energy sources. ESD heating may also be made more efficient by offsetting the heating with load shedding during charging periods. Precharging the ESD while heating or preheating the ESD by charging and discharging can prevent new maximum demand levels from appearing and thereby limit increases in demand charges.

Claims

1. A method of managing the heating of an energy storage device (ESD), the ESD having an associated temperature, the method comprising:

a. charge cycling the ESD for a charge cycling duration when said associated temperature reaches or falls below a threshold temperature, thereby generating heat within said ESD, the charge cycling comprising;

i. discharging the ESD at a discharging power level for a discharging duration to an electrical utility distribution grid, and

ii. charging the ESD at a charging power level for a charging duration from said electrical utility distribution grid;

b. wherein said discharging power level, said discharging duration, said charging power level, and said charging duration are cycle parameters, and said cycle parameters are selected to keep an average effect on an average electrical demand of a utility consumer from said electrical utility distribution grid due to the charge cycling at a predetermined target value.

2. The method of claim 1, wherein the duration of discharging and charging of the charge cycling is shortened during a final period within said charge cycling duration, the final period having a duration of one demand-averaged period or longer.

3. The method of claim 1, further comprising:

a. extending the charge cycling duration by the length of one demand-averaged period after the associated temperature rises above the threshold temperature,

b. wherein the extended charge cycling has a duration of discharging and charging that is shortened and the cycle parameters are selected in such a manner that the average effect on the average electrical demand from said electrical utility distribution grid due to the shortened charge cycling is less than or equal to zero.

4. The method of claim 1, wherein the predetermined target value is zero.

5. The method of claim 4, wherein said discharging duration and said charging duration are both entirely within one demand-averaged period.

6. The method of claim 4, wherein the ESD has an initial state of charge before charge cycling, and a final state of charge after charge cycling, and the final state of charge is greater than or equal the initial state of charge.

7. The method of claim 4, wherein the discharging duration is shorter than the charging duration, and the discharging power level is greater than the charging power level.

8. The method of claim 1, wherein the predetermined target value is less than zero.

9. The method of claim 8, wherein said discharging duration and said charging duration are both entirely within one demand-averaged period.

10. The method of claim 8, wherein the ESD has an initial state of charge before charge cycling, and a final state of charge after charge cycling, and the final state of charge is greater than or equal to the initial state of charge.

11. The method of claim 8, wherein the ESD has an initial state of charge before charge cycling, and a final state of charge after charge cycling, and the final state of charge is less than the initial state of charge.

12. The method of claim 11, wherein charge cycling takes place during a peak billing period.

13. The method of claim 1, wherein the predetermined target value is greater than zero.

14. The method of claim 13, wherein

a. the charge cycling takes place during a demand-averaged period of a billing cycle, the demand-averaged period having a demand average, and

b. the predetermined target value is sufficiently large enough to raise the demand average without exceeding a previous maximum demand average of a previous demand-averaged period in the billing cycle.

15. The method of claim 14, wherein charge cycling takes place during an off-peak billing period.

16. The method of claim 13, wherein the ESD has an initial state of charge before charge cycling, and a final state of charge after charge cycling, and the final state of charge is greater than or equal to the initial state of charge.

17. The method of claim 1, wherein charging or discharging of the ESD is disabled when the associated temperature reaches or falls below a second temperature, the second temperature being lower than the threshold temperature.

18. A method of managing the heating of a first energy storage device (ESD), the first ESD having an associated temperature, the method comprising:

discharging the first ESD at a discharging power level for a discharging duration into a second ESD and charging the first ESD at a charging power level for a charging duration from said second ESD when said associated temperature reaches or falls below a threshold temperature, thereby generating heat within the first ESD until the associated temperature rises above the threshold temperature;

preventing a state of charge of at least one of the first ESD and the second ESD from falling below a threshold state of charge level by charging the at least one of the first ESD and the second ESD using a third energy source.

19. The method of claim 18, wherein the first ESD and the second ESD are part of the same array of energy storage devices.

20. A method of managing the heating of an energy storage device (ESD), the ESD having an associated temperature, the method comprising:

a. raising the associated temperature above a threshold temperature during an off-peak period by alternately discharging and charging the ESD for the purpose of generating heat, wherein alternately charging and discharging the ESD is controlled to keep an average effect on an average electrical demand of a utility customer from an electrical utility distribution grid due to the charging and discharging at a predetermined value, the off-peak period preceding a peak period,

b. disabling charging the ESD during the peak period, and

c. enabling charging the ESD after the peak period.

21. A method of managing the heating of an energy storage device (ESD) at a site, the site having an electrical consumption level that is averaged over a demand-averaged period to form an average demand for each demand-averaged period in a billing cycle, the ESD having a state of charge, the method comprising:

a. raising the state of charge to a value above a normal level during an off-peak period by alternately discharging and charging the ESD to generate heat in the ESD in such a manner that the ESD is charged more than discharged during the off-peak period and the average demand does not exceed a previous maximum average demand of the billing cycle, the off-peak period preceding a peak period; and

b. disabling charging of the ESD during the peak period until the state of charge is depleted.