Battery charging system with internal power manager

• US 6,184,655 B1
• Filed: 12/10/1999
• Issued: 02/06/2001
• Est. Priority Date: 12/10/1999
• Status: Expired due to Term

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Malackowski, Donald
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/458,413
• Time in Patent Office: 424 Days
• Field of Search: 320/126, 320/116, 307/31, 307/32, 307/35
• US Class Current: 320/116
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/00302 Overcharge protection

Abstract

A charger (20) for simultaneously charging a plurality of batteries (22). The charger has a number of current sources (54) each of which selectively applies charging current to a separate battery. The generation of currents by the current sources is controlled by a controller (56). The controller maintains data indicating the total amount of power that the charger has available for charging batteries. When a battery is connected to a current source, the controller determines if the charger has enough power available to charge that battery. If this evaluation is positive, the controller causes the current source to supply the charging current and adjusts the power available data for the charger downwards to reflect the dedication of power to the battery. Upon the completion of the battery charging, the controller adjusts the power available data upwardly to reflect the availability of the power previously dedicated to that battery. If, however, the power availability determination is negative, the controller places the current source in a wait state in which it does not apply current to the battery. This invention prevents the current sources from collectively drawing more power than the power supply internal to the charger can provide. The charger also has a resistor 74 to which a battery is selectively connected to facilitate its discharging. The controller regulates which batteries are connected to the resistor and monitors the number of batteries connected to the resistor. The controller will not allow more than a maximum number of batteries to be simultaneously connected to the resistor.

Claims

1. A method of simultaneously charging a plurality of batteries, said method including:

providing a charger capable of simultaneously providing charging current to the plurality of batteries, the charger having power available data that indicates the amount of power the charger has available to charge the batteries; and

successively coupling the plurality of batteries to the charger so that the plurality of batteries are simultaneously coupled to the charger, and for each of the batteries coupled to the charger, with the charger;

reading from a memory power required data, the power required data indicating the power required to charge the battery;

comparing the power required for the battery to the charger power available;

if said comparison indicates that the power available to charge the batteries is at least equal to the power required to charge the battery;

subtracting from the power available the power required to charge the battery as specified by the power required data;

applying a current from the charger to the battery to charge the battery; and

, after said charging of the battery, adding back to the power available the power required to charge the battery as specified by the power required data; and

if said comparison indicates that the power available to charge the batteries is less than the power required to charge the battery, delaying the charging of said battery and reexecuting said step of comparing the power required for the battery to the charger power available.

2. The method of charging batteries of claim 1, wherein, after said step of charging the battery and said step of adding back to the power available data the power required to charge the battery, applying a trickle current to the battery until the battery is removed from the charger.

3. The method of charging batteries of claim 1, wherein:

the charger is provided with a plurality of removable modules in which the batteries are seated and each module has a memory attached thereto that contains the power required data for the type of battery inserted in the module; and

said step of reading the power required data is performed by reading the power required data stored in the module memory.

4. The method of charging batteries of claim 3, wherein:

the batteries inserted in one of the modules include memories, and the batteries memories selectively store the power required data; and

said step of reading the power required is performed by determining if the power required data is stored within the battery memory of the battery inserted in the module and, if the power required data is stored within the battery memory, reading the power required data from the battery memory and performing said comparison step based on the power required data read from the battery memory.

5. The method of charging batteries of claim 1, wherein:

at least one of the batteries coupled to the charger includes a memory; and

said step of reading the power required data for the at least one battery is performed by reading power required data for the battery stored in the battery memory.

6. The method of charging batteries of claim 1, wherein, said step of delaying the charging for a second one of the batteries is performed until said step of adding back to the power available is executed for a first one of the batteries is executed and, upon execution of the said step of adding back to the power available, the reexecution of said step of comparing the power available data for the second one of the batteries is performed.

7. The method of charging batteries of claim 1, wherein:

in said step of reading from a memory the power required data, first power required data and second power required data are read, the first power required data indicating the power required to charge the battery in a high powered charging sequence and the second power required data indicating the power required to charge in a low powered charging sequence;

a first comparison of the power required to the charger power available is performed wherein, in said first comparison, the power required for the high powered charging sequence is compared to the charger power available;

if said first comparison indicates that the power available to charge the batteries is at least equal to the power required to charge the battery in the high powered charging sequence;

subtracting from the charger power available the power required to charge the battery as specified by the first power required data;

applying a current from the charger to the battery to charge the battery in the high powered charging sequence; and

, after said charging of the battery, adding back to the charger power available the power required to charge the battery as specified by the first power required data;

if said first comparison indicates that the power available to charge the batteries is less then the power required to charge the battery in the high powered charging sequence, performing a second comparison wherein, in said second comparison, the power required for the low powered charging sequence is compared to the charger power available;

if said second comparison indicates that the power available to charge the batteries is at least equal to the power required to charge the battery in the low powered charging sequence;

subtracting from the charger power available the power required to charge the battery as specified by the second power required data;

applying a current from the charger to the battery to charge the battery in the low powered charging sequence; and

, after said charging of the battery, adding back to the charger power available the power required to charge the battery as specified by the second power required data; and

if said second comparison indicates that the power available to charge the batteries is less than the power required to charge the battery in the low powered charging sequence, performing said step of delaying the charging of the battery and reexecuting said first comparison step.

8. The method of charging batteries of claim 1, wherein:

during the charging of one of the batteries, the battery is cycled through a plurality of distinct charging states;

the memory associated with the battery cycled through distinct charging states contains power required data indicating the power required to charge the battery for each charging state;

the power required data for the plurality of charging states for the battery is read from the memory;

the battery is cycled through the charging states wherein in each said charging state, the charger;

compares the power required for the charging state to the charger power available;

if said comparison indicates that the power available to charge the batteries is at least equal to the power required to cycle the battery through the charging state;

subtracting from the power available the power required for the charging state as specified by the power required data;

applying a current from the charger to the battery to charge the battery so as to cycle the battery through the charging state; and

, after said cycling of the battery through the charging state, adding back to the power available the power required to charge the battery for the charging state as specified by the power required data; and

if said comparison indicates that the power available to charge the batteries is less than the power required to cycle the battery through the charging state, delaying the cycling of the battery through the charging state and reexecuting said step of comparing the power required for the battery charging state to the charger power available.

9. A charger for simultaneously applying charging current to a plurality of different batteries, said charging having:

a power supply capable of providing power for charging the batteries, said power supply able to provide a maximum amount of power for simultaneously charging the batteries;

a plurality of current sources, each said current source being energized by the power from said power supply and configured to be connected to one of the batteries to provide the charging current required to charge the battery, said current sources collectively configured to simultaneously charge the plurality of batteries; and

a main controller connected to said current sources for regulating the application of current from the current sources to the batteries, wherein said main controller maintains power available data indicating the power that said power supply has available to charge the batteries and, for each battery connected to a separate one for the current sources, said main controller is configured to;

determine for the battery the power required to charge the battery;

compare the power required to charge the battery to the power the power supply has available;

if the power the power supply has available is at least as much as the power required to charge the battery;

update the data indicating the power that the power supply has available by subtracting from the power available data the power required to charge the battery;

controlling said current source to which the battery is attached so that said current source charges the battery;

after the charging of the battery, update the data indicating the power that the power supply has available by adding to the power available data the power required to charge the battery; and

if the power the power supply has available is less than the power required to charge the battery;

controlling said current source to which the battery is attached so that said current source does not charge the battery; and

again performing the step of comparing the power required to charge the battery to the power the power supply has available.

10. The charger of claim 9, wherein said main controller is configured to perform the step of determining for the battery the power required to charge the battery by reading power required data from a memory associated with the battery.

11. The charger of claim 10, further including:

a plurality of modules that are removably attached to said current sources, each said module having;

a socket for receiving a battery;

conductors for establishing a connection between said current source to which said module is connected and the battery seated in the module socket; and

a memory in which the power required data for the battery are stored; and

said main controller is configured to read from said module memory the power required data to determine the power required to charge the battery.

12. The charger of claim 11, wherein:

at least one battery seated in one said module has a battery memory and the battery memory selectively includes power required data indicating the power required for the battery; and

said main controller is connected to the battery to read the battery memory and, if the battery memory includes data indicating the power required for the battery, and said main controller is configured to determine the power required for the battery on the data read from the battery memory.

13. The charger of claim 10, wherein:

at least one battery attached to the charger has a battery memory and the battery memory selectively includes power required data indicating the power required for the battery; and

said main controller is connected to the battery to read the battery memory and, if the battery memory includes data indicating the power required for the battery, said main controller is configured to determine the power required for the battery on the data read from the battery memory.

14. The charger of claim 9, wherein said main controller is further configured so that, after a said current source has charged the battery attached to said current source and after the record indicating the power that the power supply has available has been updated, said main controller regulates said current source so that said current source applies a trickle current to the battery.

15. The charger of claim 9, wherein said main controller is configured to perform the step of controlling said current source for a second battery so that the current source does not charge the second battery until the completion of the step of updating the power available data indicating the power available based on the completion of the charging of a first battery and, upon completion of the step of updating the power available data, reperforming for the second battery the step of comparing the power required to charge the battery to the power the power supply has available.

16. A charger for simultaneously applying charging current to a plurality of different batteries, said charger having:

a housing, said housing having a plurality of modules, each said module having a socket for receiving a separate battery;

a power supply disposed in said housing capable of providing power for charging the batteries, said power supply able to provide a maximum amount of power for simultaneously charging the batteries;

a plurality of current sources disposed in said housing, each said current source being energized by power from said power supply and configured to be connected to a separate one of said modules to supply to said module the charging current require to charge the battery seated in the module, said current sources collectively configured to simultaneously charge the plurality of batteries; and

a main controller connected to said current sources for regulating the application of current from the current sources to the batteries, wherein said main controller has a memory in which power available data indicating the power that said power supply has available to charge the batteries is stored and, for each said battery connected seated on one of said modules, said main controller is configured to;

determine she power required to charge the battery seated in said module;

compare the power required to charge the battery to the power the power supply has available;

if the power the power supply has available is at least as much as the power required to charge the battery;

update said main controller memory power available data by subtracting from the power available data the power required to charge the battery;

controlling said current source to which the battery is attached so that said current source charges the battery;

after the charging of the battery, update the power available data indicating the power that the power supply has available by adding to the power available data the power required to charge the battery; and

if the power the power supply has available is less than the power required to charge the battery;

controlling said current source to which the battery is connected so that said current source does not charge the battery; and

again performing the step of comparing the power required to charge the battery to the power the power supply has available.

17. The charger of claim 16, wherein said modules are removably secured to said housing.

18. The charger of claim 17, wherein:

each said module has a memory, each module memory including power required data indicating the power required to charge the battery seated in the module; and

said main controller is further configured to read from each module memory the power required data to determine the power required to charge the battery.

19. The charger of claim 18, wherein:

at least one battery has a battery memory that includes the power required data indicating the power required to charge the battery; and

said main controller is further configured to read the battery memory and, if the battery memory includes the power required data, to determine the power required to charge the battery based on the data read from the battery memory.

20. The charger of claim 16, wherein:

at least one battery has a battery memory that includes power required data indicating the power required to charge the battery seated in the module; and

said main controller is further configured to read the battery memory and, if the battery memory includes the power required data, to determine the power required to charge the battery based on the data read from the battery memory.

21. A charger for simultaneously applying charging current to a plurality of different batteries, said charger having:

a power supply capable of providing power for charging the batteries, said power supply able to provide a maximum amount of power for simultaneously charging the batteries;

a plurality of current sources, each said current source being energized by power from the power supply and configured to be connected to one of the batteries to provide the charging current required to charge the battery, said current sources collectively configured to simultaneously charge the plurality of batteries; and

a main controller connected to said current sources for regulating the application of current from said current sources to the batteries, wherein said main controller maintains a record indicating the power that said power supply has available to charge the batteries and, for each battery connected to a separate one of the current sources, said main controller is configured to;

determine for the battery the power required to charge the battery;

compare the power required to charge the battery to the power the power supply has available;

based on the comparison, selectively regulating said current source to which the battery is connected so that said current source applies current to the battery to charge the battery in a selected charging sequence from a plurality of different charging sequences; and

based on the charging sequence through which the battery is cycled, at the beginning of the charging sequence, update the record of the power available to indicate that power is being drawn by the battery and, upon completion of the charging sequence, update the record of the power available to indicate that power is no longer drawn by the battery.

22. The charger of claim 21, wherein said main controller is configured to selectively regulate at least one said current source so that, in a first charging sequence, said current source applies current to the battery to charge the battery or, in a second charging sequence, said current source does not apply charging current to the battery and, in the second charging sequence, said main controller again performs the step of comparing the power required to charge the battery to the power the power supply has available and the selective regulation of said current source to cause the battery to be selectively cycled through one of the charging sequences.

23. The charger of claim 21, wherein said main controller is configured to selectively regulate at least one said current source so that, in a first charging sequence, said current source applies current at a first current level to the battery to charge the battery or, in a second charging sequence, said current source applies current at a second current level to the battery to charge the battery, the second current level being different from the first current level.

24. The charger of claim 23, wherein said main controller is further configured to regulate said current source so that, in a third charging sequence, said current source does not apply charging current to the battery and, in the third charging sequence, said main controller again performs the step of comparing the power required to charge the battery to the power the power supply has available and the selective regulation of said current source to cause the battery to be selectively cycled through one of the charging sequences.

25. A method of simultaneously charging a plurality of batteries, said method including:

providing a charger capable of simultaneously providing charging current to the plurality of batteries, the charger having power available data that indicates the amount of power the charger has available to charge the batteries; and

successively coupling the plurality of batteries to the charger, and for each of the batteries coupled to the charger, with the charger;

determining for the battery the power required to charge the battery;

comparing the power required for the battery to the charger power available data;

based on said comparison, selectively applying current to the battery to cycle the battery through one of a plurality of different charging sequences; and

based on the charging sequence through which the battery is cycled, at the beginning of the charging sequence, updating the power available data at the beginning of said step of cycling the battery through the charging sequence to indicate that power that will be drawn by the battery and, at the end of said step of cycling the battery through the charging sequence, updating the power available data to indicate that power is no longer drawn by the battery.

26. The method of charging batteries of claim 25, wherein the charger cycles the battery through:

a first charging sequence in which the charger applies current to the battery to charge the battery;

or

a second charging sequence, wherein in said second charging sequence, the charger does not apply charging current to the battery and said charger reexecutes said step of comparing the power required for the battery to the charger power available data.

27. The method of charging batteries of claim 25, wherein the charger cycles the battery through:

a first charging sequence in which the charger applies current to the battery to charge the battery, wherein, in the first charging sequence, the current is applied to the battery at a first current level;

or

a second charging sequence, wherein, in said second charging sequence, the charger applies current to the battery to charge the battery, wherein, in the second charging sequence, the current is applied to the battery at a second current level, the second current level being different from the first current level.

28. The method of charging batteries of claim 27, wherein the charger is further configured to selectively cycle the battery through a third charging sequence, wherein in said third charging sequence, the charger does not apply charging current to the battery and said charger reexecutes said step of comparing the power required for the battery to the charger power available data.

29. A method of simultaneously charging a plurality of batteries, said method including the steps of:

providing a charger capable of simultaneously providing charging current to the plurality of batteries, the charging having a load resistor and a data field that indicates the number of batteries attached to the load resistor; and

coupling the plurality of batteries to the charger and, for each of the batteries, with the charger;

cycling the battery through a plurality of charging states, wherein in at least one charging state current is applied to the battery to charge and, in one said charging state a determination is made if the battery needs to be subjected to a discharging cycle;

if, in said discharge cycle determination step, it is determined that the battery does not need to be subjected to a discharging cycle, continuing said step of cycling the battery through the plurality of charging states;

if, in said discharge cycle determination step, it is determined that the battery needs to be subjected to a discharging cycle, performing a load resistor availability step to determine, by reference to the load resistor data field, if a maximum number of batteries are connected to the load resistor;

if, in said load resistor availability step it is determined that less than a maximum number of batteries are connected to the load resistor;

updating the load resistor data field to indicate an additional battery is connected to the load resistor;

executing the discharging cycle by connecting the battery to the load resistor;

upon termination of the discharging cycle, disconnecting the battery from the load resistor and updating the load resistor data field to indicate the battery is disconnected from the load resistor; and

continuing with said step of cycling the battery through the plurality of charging states; and

if, in said load resistor availability step it is determined that the maximum number of resistors are connected to the load resistor, bypassing execution of the discharging cycle and continuing with said step of cycling the battery through the plurality of charging states.

30. The method of simultaneously charging a plurality of batteries of claim 29, wherein the maximum number of batteries that can be attached to the load resistor is one.

31. The method of simultaneously charging a plurality of batteries of claim 29, wherein:

the battery which is subjected to said discharging cycle has an internal memory, the internal memory containing cycles since discharge data indicating how many times the battery has been charged since the battery was last cycled through the discharging cycle;

for the battery which is subjected to said discharging cycle, as part of said step of cycling the battery through a plurality of charging states, updating the cycles since discharge data to indicate an additional charging of the battery;

for the battery which is subjected to said discharging cycle, performing said discharge cycle determination step by comparing the cycles since discharge data for the battery to a fixed number of charging cycles and, if said comparison indicates the battery has been cycled through the charging states for less than the fixed number, not subjecting the battery to said discharging cycle or, if said comparison indicates that the battery has been cycled through a number of charging states for at least equal to the fixed number of charging cycles, executing said load resistor availability step; and

if, after said load resistor availability step, the battery is cycled through the discharging cycle, zeroing out the cycles since discharge data in the battery memory.

32. A method of simultaneously charging a plurality of batteries, said method including:

providing a charger capable of simultaneously providing charging current to the plurality of batteries, the charger having power available data that indicates the amount of power the charger has available to charge the batteries and a load resistor to which the batteries are selectively coupled to discharge the batteries; and

successively coupling the plurality of batteries to the charger, and for each of the batteries coupled to the charger, with the charger;

charging the battery with a charge supplied by the power supply;

determining for the battery if the battery is to be discharged wherein, if the battery is not be discharged actuating a display to indicate that the battery is available for use;

if the battery is to be discharged, determining if a maximum number of batteries are simultaneously connected to the load resistor; and

if the maximum number of batteries are not connected to the load resistor, connecting the battery to the load resistor to discharge the battery, wherein after said discharging of the battery, the battery is disconnected to the load resistor and said step of charging the battery is reexecuted; and

maintaining a count of the number of batteries connected to the load resistor.

33. The method of simultaneously charging a plurality of batteries of claim 32, wherein the maximum number of batteries that can be attached to the load resistor is one.

34. The method of simultaneously charging a plurality of batteries of claim 32, wherein said step of determining if the battery is be discharged includes the steps of:

determining if the battery is of a type requiring periodic discharging wherein; and

if the battery is of a type requiring period discharging;

determining how many times the battery has been charged since the last discharging of the battery; and

performing a first comparison comparing the number of times the battery has been charged since the last discharging to a first trigger count, if said first comparison indicates that the battery has been charged is less than the first trigger count, determining that the battery does not require discharging; and

if the said first comparison indicates the number of time the battery has been charged is at least equal to the first trigger count, determining that the battery requires discharging.

35. The method of simultaneously charging a plurality of batteries of claim 32, wherein, for a battery, in said step of determining the number of batteries connected to the load resistor, it is determined that the maximum number of batteries are connected to the load resistor, actuating the display to indicate that the battery is available for use.

36. The method of simultaneously charging a plurality of batteries of claim 34, wherein, for a particular battery:

if the maximum number of batteries are connected to the load resistor, performing a second comparison comparing the number of times the battery has been charged since the last discharging to a second trigger count;

if said second comparison indicates that the battery has been charged is less than the second trigger count, actuating the display to indicate that the battery is available for use; and

if said second comparison indicates that the number of time the battery has been charged is at least equal to the second trigger count, reexecuting said step of determining if the maximum number of batteries are connected to the load resistor so as to force the discharging of the battery.

37. A charger for simultaneously applying charging current to a plurality of different batteries, said charger having:

a power supply capable of providing power for charging the batteries, said power supply able to provide a maximum amount of power for simultaneously charging the batteries;

a plurality of current sources, each said current source being energized by power from the power supply and configured to be connected to one of the batteries to provide the charging current required to charge the battery, said current sources collectively configured to simultaneously charge the plurality of batteries;

a load resistor and a plurality of load resistors switches, each said load resistor switch configured to selectively connect one battery to the load resistor; and

a main controller connected to said current sources for regulating the application of current from the current sources to the batteries and to said load resistor switches, wherein said main controller maintains a record of the number of batteries simultaneously connected to said load resistor and, for each battery connected to a separate one for the current sources, said main controller is configured to;

regulate the charging of the battery by the current source; and

selectively actuate one of said load resistor switches to connect the battery to said load resistor, wherein said main controller is configured to simultaneously connect a maximum number of the batteries to said load resistor.

38. The charger of claim 37, wherein the maximum number of batteries the main controller simultaneously connects to the load resistor is one.

39. The charger of claim 37, wherein said main controller is further configured to selectively connect the battery to said load resistor based on:

the type of battery and the number of times the battery has been charged since the battery was last connected to said load resistor.

40. The charger of claim 39, wherein said main controller determines the number of times the battery has been charged since the battery was last connected to said load resistor by reading data from a memory internal to the battery.