Method and Apparatus for Charging a Lead Acid Battery

• US 20120139475A1
• Filed: 07/27/2010
• Published: 06/07/2012
• Est. Priority Date: 08/06/2009
• Status: Active Grant

• Current Assignee: EH Europe GmbH (EnerSys)
• Original Assignee: EH Europe GmbH (EnerSys)
• Inventors: Evans, Rhodri, Coldrick, Wayne
• Granted Patent: US 9,553,470 B2
• Time in Patent Office: Days
• US Class Current: 320/106
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: H02J 7/00716 in response to integrated charge or discharge current
• CPC Class Codes: H02J 7/007186 obtained with the battery disconnected from the charge or discharge circuit
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

The invention relates to a method of operating a lead acid battery which undergoes discharging phases and charging phases in a cyclical fashion. The method involves monitoring the current discharged from the battery during a discharging phase and recording information relating to that current flow, such as the charge lost from the battery. During the subsequent charging phase, a desired amount of charge to be supplied to the battery is calculated based upon the recorded information, and then supplied to the battery.

Claims

1. A method of operating a lead acid battery in which the battery undergoes discharging phases during which the battery is discharged and charging phases during which the battery is charged and which includes

during a discharging phase, monitoring the current flow out of and into the battery, and recording information relating to that current flow;

during a subsequent charging phase, calculating, based upon that recorded information, a desired amount of charge to be supplied to that battery, and supplying that desired amount of charge to the battery.

2. A method according to claim 1 in which the charging of the battery during a charging phase involves calculating the net amount of charge removed from the battery.

3. A method according to claim 2 in which the desired amount of charge to be supplied to the battery is calculated by multiplying the calculated net amount of charge removed from the battery by a predetermined charge factor.

4. A method as claimed in claim 3 in which the charge factor varies though the lifetime of the battery.

5. A method as claimed in claim 4 in which the charge factor increases over the lifetime of the battery.

6. A method as claimed in claim 4 in which the charge factor decreases in a first part of the lifetime of the battery and then increases in a second, later part of the lifetime of the battery.

7. A method according to claim 3 in which the battery is a thin plate pure lead (TPPL) battery and in which the predetermined charge factor is within the range of from 1.01 to 1.12.

8. A method according to claim 3 in which the battery is a flooded battery and the predetermined charge factor is within the range of from 1.05 to 1.30.

9. A method according to claim 3 in which the battery is a gelled battery and in which the predetermined charge factor is within the range of from 1.05 to 1.20.

10. A method as claimed in claims 1 in which during the charging phase current flow into the battery is monitored thereby allowing the amount of charge supplied to the battery to be calculated.

11. A method according to claim 1 in which the current flow into and out of the battery is monitored using a shunt.

12. A method according to claim 11 in which the current into and out of the battery is monitored by two shunts, a first shunt for monitoring a lower current range and a second shunt for monitoring an upper current range.

13. A method of operating a lead acid battery in which the battery is operated according to the method of claim 1 during only part of the lifetime of the battery.

14. A method of operating a lead acid battery as claimed in claim 13 in which the battery is operated according to the method of claim 1 during one period of its lifetime and during another period of its lifetime, is operated according to a second method in which

the battery undergoes discharging phases during which the battery is discharged and charging phases during which the battery is charged and which involves:

a) monitoring and recording information relating to the discharging and/or charging history of the battery;

b) during a charging phase connecting the battery to a charging apparatus and applying a voltage to the battery wherein the voltage is adjusted in dependence on the recorded information relating to the discharging and/or charging history of the battery.

15. A method of operating a lead acid battery as claimed in claim 14 in which the battery is operated in an initial, first period according to the second method and in which in a subsequent, second period is operated according to the method of claim 1.

16. A method of operating a lead acid battery as claimed in claim 14 in which in the second method the voltage is adjusted in dependence on the recorded information relating to the discharging and/or charging history of the battery such that the voltage applied to the battery during charging phases progressively reduces over the period the battery is operated according to the second method.

17. A method of operating a lead acid battery as claimed in claim 14 in which in the second method the information relates to at least one parameter relating to the discharging and/or charging history of the battery, and the voltage applied to the battery is adjusted such that it reduces stepwise at predetermined values of the parameter.

18. A method of operating a lead acid battery as claimed in claim 14 in which in the second method the information relating to the discharging and/or charging history of the battery is the total charge discharged from the battery or the total charge supplied to the battery during charging.

19. A method of operating a lead acid battery as claimed in claim 14 in which in the second method the information relating to the discharging and/or charging history of the battery is the total charge supplied to the battery during charging.

20. A method of operating a lead acid battery as claimed in claim 14 in which the second method also involves measuring the temperature of the battery during the charging of the battery and adjusting the voltage applied to the battery in dependence on that temperature.

21. An energy storage and supply apparatus comprising:

one or more lead acid batteries;

means to monitor the current flow out of and into the or each battery during use of the or each battery;

means to record information relating to the current flow out of and into the or each battery during use of the or each battery; and

a charging apparatus for charging the or each battery comprising control means arranged to calculate a desired amount of charge to be supplied to the or each battery based upon the recorded information relating to the current flow out of and into the or each battery during use of the or each battery.

22. An energy storage and supply apparatus as claimed in claim 21 in which each battery comprises one or more shunts for monitoring the current flow out of and into the battery.

23. An energy storage and supply apparatus as claimed in claim 21 in which each battery comprises information storage means to store the recorded information relating to the current flow to and from the battery during use of the battery.

24. An energy storage and supply apparatus as claimed in claim 21 which comprises wireless communication means for communicating the recorded information relating to the current flow in to and out of the battery during use of the battery from each battery to the charging apparatus.

25. An energy storage and supply apparatus as claimed in claim 21 in which the control means is also arranged to control a voltage applied to the battery during charging of the battery in dependence on recorded information relating to the discharging and/or charging history of the or each battery.

26. A charging apparatus for charging a lead acid battery comprising

a) communication means arranged to obtain information relating to the current flow out of and into the battery during use of the battery;

b) control means arranged to calculate, based upon the information relating to the current flow out of and into the battery during use of the battery, a desired amount of charge to be supplied to the battery; and

c) current supply means arranged to supply the calculated desired amount of charge to the battery.

27. A charging apparatus as claimed in claim 26 in which the charging apparatus is also arranged to obtain information relating to the discharging and/or charging history of the battery and the control means is arranged to control a voltage applied to the battery during charging of the battery in dependence on the recorded information relating to the discharging and/or charging history of the battery.

28. A charging apparatus as claimed in claim 26 in which the communication means is a wireless communication apparatus arranged to wirelessly communicate with a monitoring and recording unit on the battery which monitors and records the information relating to the discharging and/or charging history of the battery.