Battery charger especially useful with sterilizable, rechargeable battery packs

• US 6,018,227 A
• Filed: 06/22/1998
• Issued: 01/25/2000
• Est. Priority Date: 06/22/1998
• Status: Expired due to Term

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Kumar, Yashdeep, Malackowski, Donald
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/102,142
• Time in Patent Office: 582 Days
• Field of Search: 320/106, 320/128, 320/132, 320/116, 320/134, 320/136, 320/144, 320/150, 320/112
• US Class Current: 320/106
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H02J 2310/22 The load being a portable electronic device
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery charger (20) for charging batteries to which different charging currents are applied in different instruction sequences. The charger includes a microprocessor (124) that controls the generation of current by a current source (110). A removable module (26) is attached to the charger for holding a particular type of battery. A memory (70) internal to the module contains data indicating the sequences in which charging currents are to be applied to the battery and when tests should be executed to determine if the battery should exit a particular charging step. The module memory also contains data indicating the currents that should be applied to the battery with which it is associated and the parameters of the exit condition tests. The charger is ideally used with a battery that has both and internal temperature sensor (286) and its own memory (282). The temperature sensor provides data useful for accurately determining the stored charge within the battery. The battery memory contains data indicating how often the battery has been charged. These data are useful for evaluating the charge the battery should be able to store.

Claims

1. A charger for providing an energization current to a battery, said charger having:

a base unit;

a module adapted to be releasably connected to the base unit, said module having a socket for receiving the battery and electrical contacts for establishing a conductive path between said base unit and the battery over which a charging current is applied to the battery;

a first memory associated with the battery for storing sequence data indicting a sequence in which charging current is applied to the battery;

a current source disposed in said base unit, said current source being configured to generate a variable charging current and that is connected to said electrical contacts of said module to apply the charging current to the battery and that is configured to provide a MEASURED_-- VOLTAGE signal representative of voltage across the battery, wherein said current source generates the charging current at a specific level to the battery based on a received CURRENT_-- CONTROL signal; and

a processor unit disposed in said base unit, said processor unit being connected to said first memory for reading the sequence data and being connected to said current source, wherein said processor unit;

receives the MEASURED_-- VOLTAGE signal;

performs tests on the MEASURED_-- VOLTAGE signal;

generates the CURRENT_-- CONTROL signal to said current source as a function of the results of the tests of the MEASURED_-- VOLTAGE signal;

is configured to test the MEASURED_-- VOLTAGE signal and generate the CURRENT_-- CONTROL signal in a plurality of different sequences; and

tests the MEASURED_-- VOLTAGE signal and generates the CURRENT_-- CONTROL signal in a specific sequence based on the sequence data read from said first memory.

2. The charger of claim 1, wherein said first memory is contained in said module.

3. The charger of claim 1, wherein:

said first memory further includes data indicating the level of the current to be applied to the battery; and

said processor unit reads the current level data stored in said first memory and generates the CURRENT_-- CONTROL signal based on the current level data.

4. The charger of claim 3, wherein:

said first memory further includes data indicating the test levels of the MEASURED_-- VOLTAGE signal; and

said processor unit is configured to;

read the MEASURED_-- VOLTAGE test level data stored in said first memory;

compare the MEASURED_-- VOLTAGE signal from the current source to the MEASURED_-- VOLTAGE test level data read from said first memory; and

selectively generate the CURRENT_-- CONTROL signal based on the results of the comparisons of the MEASURED_-- VOLTAGE signal to the MEASURED_-- VOLTAGE test level data.

5. The charger of claim 1, wherein:

said first memory further includes data indicating the test levels of the MEASURED_-- VOLTAGE signal; and

said processor unit is configured to;

read the MEASURED_-- VOLTAGE test level data stored in said first memory;

compare the MEASURED_-- VOLTAGE signal from the current source to the MEASURED_-- VOLTAGE test level data read from said first memory; and

selectively generate the CURRENT_-- CONTROL signal based on the results of the comparisons of the MEASURED_-- VOLTAGE signal to the MEASURED_-- VOLTAGE test level data.

6. The charger of claim 1, wherein:

said first memory further includes time set point data; and

said processor unit reads the time set point data from said first memory and generates the CURRENT_-- CONTROL signal for a select amount of time based on the time set point data read from said first memory so that said current source generates the charging current for a select amount of time to the battery based on the time set point data.

7. The charger of claim 1, wherein:

a display is connected to said base unit;

said module further includes;

a load resistor; and

a switch circuit for selectively connecting said load resistor across the battery in respond to a GATE signal;

said sequence data in said first memory further includes data indicating when said load resistor is to be tied across said battery; and

said processor unit;

is connected to said load resistor for receiving an indication of voltage across said load resistor when said load resistor is connected across the battery;

selectively generates the GATE signal to cause the load resistor to be tied across the battery so that the voltage across the load resistor is measured in a specific sequence based on the sequence data in said first memory; and

causes an image to be presented on said display indicating the stored energy in the battery based on the voltage across said load resistor.

8. The charger of claim 7, wherein said load resistor is connected to said current source so that when said load resistor is connected across the battery, the MEASURED_-- VOLTAGE signal is representative of voltage across said load resistor.

9. The charger of claim 1, wherein:

the battery includes a temperature sensor that generates a signal representative of the internal temperature of the battery;

said processor unit is connected to the temperature sensor for determining the temperature of the battery; and

based on the sequence data read from said first memory, said processor unit selectively tests the temperature of the battery and, based on the temperature tests, generates the CURRENT_-- CONTROL signal.

10. The charger of claim 1, wherein:

said processor unit is configured to selectively perform a plurality of different types of tests on the MEASURED_-- VOLTAGE signal; and

said processor unit performs selected ones of the tests on the MEASURED_-- VOLTAGE signal based on the sequence data read from said first memory.

11. A method of charging a battery comprising the steps of:

providing a charging unit with a current source capable of applying a variable charging current to the battery and a voltage measurement circuit capable of measuring the voltage across the battery;

providing a memory that is removably attachable to the charging unit, the memory storing data indicating;

the sequence in which the charging current is applied to the battery and the voltage across the battery is to be measured;

the level of the current that is applied to the battery; and

voltage set points of the voltage across the battery;

connecting the battery to the charging unit and attaching the memory to charging unit;

reading the data from the memory; and

operating the charging unit so that;

the current source applies current to the battery and the voltage measurement circuit selectively tests the voltage across the battery in a sequence specified by the sequence data in the memory; and

the current source applies current to the battery based on the current level data in the memory and comparisons of the voltage across the battery with the voltage set point data in the memory.

12. The method of charging a battery of claim 11, further including the steps of:

providing a module having a socket for receiving the battery and wherein said memory is attached to the module;

releasably attaching the module to said charging unit;

after said attachment of the module to the charging unit, performing said read of data in the memory;

seating the battery in the socket of the module; and

performing said application of current from the current source to the battery through the module.

13. The method of charging a battery of claim 11, further including the steps of:

providing a load resistor;

selectively connecting the load resistor across the battery and measuring the voltage across the load resistor based on the sequence data in the memory; and

presenting an indication of the energy stored in battery on a display based on the voltage measured across the load resistor.

14. The method of charging a battery of claim 11, wherein:

the charging unit is provided with data defining a plurality of different instruction sequences, each instruction sequence including instructions that define a select sequence in which the current is to be applied to the battery and the voltage across the battery is to be tested and the tests that are to be performed on the voltage across the battery;

the data in the memory identifies the instruction sequences that are to be executed in order to charge the battery; and

said step of operating the charging unit is performed by causing the current source to apply current to the battery and the voltage measurement circuit to perform tests on the voltage across the battery in the specific sequences and to cause the voltage measurement circuit to perform the specific tests on the voltage across the battery defined by the instruction sequences identified for execution in the data read from the memory.

15. The method of charging a battery of claim 12, wherein:

the memory in the module is a first memory and the data in the first memory is a first set of sequence data indicating;

the sequence in which the charging current is applied to the battery and the voltage across the battery is be measured;

the amount of current that is applied to the battery; and

voltage set points of the voltage across the battery;

the battery to be charged is provided with a second memory that stores a second set of sequence data indicating;

the sequence in which the charging current is applied to the battery and the voltage across the battery is be measured;

the amount of current that is applied to the battery; and

voltage set points of the voltage across the battery;

after said step of releasably attaching the module to said charging unit, the first set of sequence data from the first memory is read;

after said step of connecting the battery to the charging unit, the second set of sequence data from the second memory is read; and

the charging unit is selectively operated based on either the sequence specified by the first set of sequence data or the sequence specified by the second set of sequence data.

16. The method of charging a battery of claim 11, wherein:

the battery to be charged is provided with the memory with the memory; and

after said step of connecting the battery to the charging unit, reading the data from the memory in the battery.

17. A module for use with a battery charger, said module including:

a shell defining a socket for receiving a battery;

a securement mechanism attached to said shell, said securement mechanism being configured to releasably secure said shell to the battery charger;

a plurality of conductive members attached to said shell for establishing a conductive path between the battery charger and the battery over which a charging current is applied to the battery and over which the voltage across the battery can be measured;

a load resistor in said shell and a switch assembly in said shell for selectively connecting said load resistor across the battery; and

a memory unit secured to said shell, said memory unit storing data readable by the battery charger indicating a sequence in which;

a charging current is to be applied to the battery;

the voltage across the battery is to be measured and;

said load resistor is to be connected across the battery.

18. The module of claim 17, wherein the data in said memory unit indicates:

which of a plurality of different charging states through which the battery should be cycled in order to charge the battery;

for each charging state, the current that should be applied to the battery;

for each charging state, an indication of the specific one of a plurality of instruction sequences that should be executed, each instruction sequence identifying;

the order in which the battery should be charged and at least one exit test performed on the battery in order to determine if the battery should exit the charging state; and

the at least one exit test that is to be performed on the battery to determine if the battery should exit the charging state; and

for each charging state, the next charging state the battery should enter based on the result of the at the at least one exit test.

19. The module of claim 17, wherein said module includes a plurality of first contacts through which the charging current is applied to the battery and at least one second contact that is separate from said first contacts over which data signals are read from the battery.

20. A charger for supplying a charging current to a battery, wherein a memory is associated with the battery that provides sequence data indicating the order in which processes are executed to charge the battery, said charger having:

a current source configured for connection to the battery, said current source configured to generate a variable charging current to the battery based on a received CURRENT_-- CONTROL signal and to provide a MEASURED_-- VOLTAGE signal representative of the voltage across the battery; and

a processor connected to the memory for reading the sequence data and connected to said current source for generating the CURRENT_-- CONTROL signal and to receive the MEASURED_-- VOLTAGE signal wherein, said processor;

performs a plurality of different tests on the MEASURED_-- VOLTAGE signal;

generates the CURRENT_-- CONTROL signal based on results of the tests performed on the MEASURED_-- VOLTAGE signal; and

perform specific MEASURED_-- VOLTAGE tests and generate the CURRENT_-- CONTROL signal in a specific sequence based on the sequence data read from the memory.

21. The charger of claim 20, wherein:

the memory includes data indicating the level of current to be applied to the battery; and

said processor reads the current level data from the memory and generates the CURRENT_-- CONTROL signal based on the current level data.

22. The charger of claim 20, wherein:

the memory further includes data indicating the test levels of the MEASURED_-- VOLTAGE signal; and

said processor is configured to;

read the MEASURED_-- VOLTAGE test level data stored in said the memory;

perform the MEASURED_-- VOLTAGE tests by comparing the MEASURED_-- VOLTAGE signals from the current source to the MEASURED_-- VOLTAGE test level data read from the memory; and

selectively generate the CURRENT_-- CONTROL signal based on the results of the comparisons of the MEASURED_-- VOLTAGE signals to the MEASURED_-- VOLTAGE test level data.

23. The charger of claim 20, wherein:

the memory further includes time set point data; and

said processor reads the time set point data from the memory and generates the CURRENT_-- CONTROL signal for select amounts of time based on the time set point data read from the memory so that said current source applies at least one charging current for a select amount of time to the battery based on the time set point data.

24. The charger of claim 20, wherein said processor unit:

stores a plurality of instruction sequences, each said instruction sequence comprising a set of instructions that indicate a specific order in which specific MEASURED_-- VOLTAGE tests are performed and in which specific CURRENT_-- CONTROL signals are generated;

determines at least one selected instruction sequence from the sequence data read from the memory; and

performs specific MEASURED_-- VOLTAGE tests and generates CURRENT_-- CONTROL signals in the order specified by the at least one selected instruction sequence.

25. The charger of claim 20, further including a module removably connected to said current source for receiving the battery, said module having a socket in which the battery is seated and a plurality of contacts for establishing an electrical connection between the battery and said current source.

26. The charger of claim 25, wherein:

the memory is in the battery; and

the module includes conductive member through which the data in the memory is read by said processor.

27. The charger of claim 25, wherein the memory is attached to said module.

28. A method of charging a rechargeable battery, said method comprising the steps of:

providing a rechargeable battery that is recharged by cycling the battery through a plurality of charging states;

providing a memory that is associated with the battery, the memory storing data indicating an instruction sequence to be executed when the battery is in a specific charging state and the next charging state of the battery when the battery is in each charging state;

providing a charger capable of supplying a charging current to the battery and measuring the voltage across the battery, wherein the charger is capable of supplying charging current to the battery and measuring the voltage across the battery in a plurality of different sequences, each different sequence being based on a different one of the instruction sequences;

connecting the battery to the charger and reading the instruction sequence data and next charging state data from the memory into the processor; and

cycling the battery through a plurality of charging states wherein the charging states through which the battery is cycled is based on the next charging state data read from the memory and, in each charging state, the charger supplies current to the battery and measures the voltage across the battery according to the instruction sequence specified for the charging state based upon the instruction sequence data for the charging state read from the memory.

29. The method of charging a battery of claim 28, wherein the charging states through which the battery is cycled are a function of the results of the voltage measured across the battery.

30. The method of charging a battery of claim 28, wherein the charger supplies current to the battery and measures the voltage across the battery in an order specified by the same instruction sequence when the battery cycles through a plurality of charging states.

31. The method of charging a battery of claim 28, wherein:

the memory includes data indicating the current to be applied to the battery when the charger is in each charging state; and

in each charging state, the charger supplies a selected current to the battery based on the current data in the memory.

32. A method of charging a battery comprising the steps of:

reading data from a memory associated with the battery that defines;

which of a plurality of different charging states through which the battery should be cycled in order to charge the battery;

for each charging state, the current that should be applied to the battery during the charging state;

for each charging state, a specific instruction sequence that should be executed, each instruction sequence identifying;

the order in which the battery should be charged and at least one exit test that is performed on the battery in order to determine if the battery should exit the charging state;

the at least one exit test that is to be performed on the battery; and

the next charging state the battery should entry based on the results of the at the at least one exit test;

based on the data read from the memory associated with the battery, cycling the battery through the charging states specified in the data wherein, in each charging state;

current is selectively applied to the battery based on the current specifying data for that charging state;

the current is applied to the battery and the at least one exit test is performed on the battery in the order identified in the instruction sequence specified for the charging state;

the at least one exit test specified for the battery in the instruction sequence specified for the charging state is performed; and

based on the results of the at least one exit test performed on the battery and the data identifying the next charging state of the battery based on the results of the at least one exit test, the battery is selectively cycled to the next charging state.

33. The method of charging a battery according to claim 32, wherein;

said step of applying current to the battery is performed performed with a current source capable of generating a variable output current;

said step of reading the data associated with the memory is performed by a processor; and

said processor, based on the read data;

regulates the application of current to the battery by the current source;

performs the at least one exit test on the battery;

determines, based on the at least one exit test, the next charging state through which the battery should be cycled.

34. The method of charging of battery of claim 32, wherein the at least one exit test performed on the battery includes one selected from the group of:

determining if the voltage across the battery exceeds a maximum voltage;

determining if the voltage across the battery is less than a minimum voltage;

determining if the battery has been in the specified charging state for a time greater than a maximum time;

determining if there is a specific change in voltage across the battery;

determining if the battery exceeds a specific temperature; and

determining if there is a specific change in the temperature of the battery.

35. The method of charging a battery of claim 32, wherein:

specific ones of the instruction sequences specify plural exit tests that are performed on the battery to determine if the battery should exit the charging state and the order in which the exit tests are to be performed;

when the data read from the memory indicates that one of the instruction sequences that specifies that plural exit tests are to be performed on the battery is to be executed, during said cycling of the battery through the specified charging state, the plural exit tests identified in the instruction sequence are performed on the battery and are performed in the order specified in the instruction sequence.

36. The method of charging a battery of claim 32, wherein:

said step of reading data from a memory associated with the battery is performed by reading data in a memory that is attached to module; and

said battery is placed in the module and, in said step of selectively applying current to the battery, the charging current is applied to the battery through conductors integral with the module.

37. A charger for energizing a battery including:

a current source for applying a variable charging current to the battery in response to a CURRENT_-- CONTROL signal;

a processor memory containing data defining a plurality of different instruction sequences, each instruction sequence identifying;

the order in which the battery should be charged and at least one exit test that is performed on the battery in order to determine if the battery should exit a charging state; and

the type of the at least one exit test that is to be performed on the battery; and

a processor unit connected to said current source and to said processor memory, said processor unit configured to;

read data from a memory associated with the battery that identifies;

the charging states through which the battery should be cycled in order to charge the battery;

for each charging state, the current that should be applied to the battery during the charging state;

for each charging state, the specific one of the plurality of instructions sequences that should be executed when the battery is in the charging state; and

, for each charging state, the next charging state the battery should enter based on the results of the at least one exit test;

cycle the battery through the plurality of charging states specified by the data read from the memory associated with the battery wherein, in each charging state, said processor unit; and

generates the CURRENT_-- CONTROL signal to said current source to cause said current source to apply the current to the battery specified in the data read from the memory associated with the battery;

causes said current source to apply current to the battery and performs the at least one exit test on the battery in the order specified by the instruction sequence specified for the charging state;

performs the at least one exit test for the charging state based on the data in the instruction sequence specified for the charging state; and

based on the results of the at least one exit test performed on the battery and the data indicating the next charging state of the battery read from the memory, selectively cycling the battery to the next charging state.

38. The charger of claim 37, wherein:

a voltage measurement circuit is provided for evaluating the voltage across the battery;

said processor unit is connected to said voltage measurement unit and is configured to perform the following exit tests;

determine if the voltage across the battery exceeds a maximum voltage;

determine if the voltage across the battery is less than a minimum voltage;

determine if the battery has been in the specified charging state for a time greater than a maximum time;

determine if there is a specific change in voltage across the battery.

39. The charger of claim 37, wherein:

a temperature sensor is positioned to monitor the temperature of the battery; and

said processor unit is connected to said temperature sensor to receive a signal representative of the temperature of the battery and is further configured to perform the following exit tests;

determine if the battery exceeds a specific temperature; and

determine if there is a specific change in the temperature of the battery.

40. The charger of claim 37, wherein:

at least one of the instruction sequences stored in said processor memory identifies plural exit tests that are performed on the battery to determine if a battery should exit a charging state and the order in which the exit tests are to be performed;

when the data read from the memory associated with the battery indicates that, for a particularly charging state, the instruction sequence that identifies plural exits tests should be executed, during the cycling of through that charging state by said processor unit, said processor unit performs the plural exits tests identified in the instruction sequence in the order specified by the instruction sequence.

41. The charger of claim 37, further including a module removably connectable to said current source and said processor unit, said module having:

a socket for removably receiving the battery;

conductors through which the charging current is applied from said current source to the battery; and

a memory, said module memory being the memory in which the data identifying the charging states through the battery should be cycled;

the current applied to the battery in each charging state and the instruction sequences that should be executed in each charging state is stored and wherein,

said processor unit is connected to said module memory for reading the data from the module memory.

42. A module for use with a battery charger, said module including:

a shell defining a socket for receiving a battery;

a securement mechanism attached to said shell, said securement mechanism being configured to releasably secure said shell to the battery charger;

a plurality of conductive members attached to said shell for establishing a conductive path between the battery charger and the battery over which a charging current is applied to the battery and over which the voltage across the battery can be measured; and

a memory unit secured to said shell, said memory unit storing data readable by the battery charger indicating a sequence in which a charging current is to be applied to the battery and the voltage across the battery is to be measured, wherein the data indicates;

specific charging states from a plurality of charging states the through which the battery should be cycled in order to charge the battery;

for each charging state, the current that should be applied to the battery;

for each charging state, an indication of the specific one of a plurality of instruction sequences that should be executed, each instruction sequence identifying;

the order in which the battery should be charged and at least one exit test that is performed on the battery in order to determine if the battery should exit the charging state;

the at least one exit test is performed on the battery to determine if the battery should exit the charging state; and

for each charging state, the next charging state the battery should enter based on the result of the at least one exit test.

43. The module of claim 42, wherein said module includes a plurality of first contacts through which the charging current is applied to the battery and at least one second contact that is separate from said first contacts over which data signals are read from said memory.

44. The module of claim 42, further including a load resistor in said shell and a switch assembly in said shell for selectively connecting said load resistor across the battery.

45. A rechargeable battery pack comprising:

a housing;

at least one rechargeable cell disposed in said housing;

a first set of terminals attached to said housing that are attached to said at least one rechargeable cell, wherein energy is applied to said first set terminals for storage in said at least one rechargeable cell and current is drawn from said at least one rechargeable cell through said first set terminals;

a memory disposed in said housing, said memory including data readable by a battery charger indicating a sequence in which a charging current is to be applied to the battery and the voltage across the battery is to be measured, wherein the data indicates;

specific charging states from a plurality of charging states the through which the battery should be cycled in order to charge the battery;

for each charging state, the current that should be applied to the battery;

for each charging state, an indication of the specific one of a plurality of instruction sequences that should be executed, each instruction sequence identifying;

the order in which the battery should be charged and at least one exit test is performed on the battery in order to determine if the battery should exit the charging state;

the at least one exit test that is performed on the battery to determine if the battery should exit the charging state; and

for each charging state, the next charging state the battery should enter based on the result of the at least one exit test;

a second set of terminals attached to said housing and connected to said memory, wherein the data are read from said memory over the second set of terminals.

46. The battery of claim 45, wherein:

said memory further includes a data storage field in which data representative of the number of times the battery has been charged are stored and a plurality of second data storage fields in which data representative of the energy stored in the battery after charging are stored.

47. The rechargeable battery of claim 45, wherein one of said first set terminals functions is a ground terminal for signals exchanged over said second set terminals.

48. The rechargeable battery of claim 45, further including a temperature sensor internal to said battery, wherein said temperature sensor generates a temperature signal representative of battery temperature.