Method and system for charging multi-cell lithium-based batteries

• US 8,525,479 B2
• Filed: 09/13/2011
• Issued: 09/03/2013
• Est. Priority Date: 11/22/2002
• Status: Active Grant

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Meyer, Gary D., Rosenbecker, Jay J., Glasgow, Kevin L., Johnson, Todd W., Scheucher, Karl F.
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US13/231,449
• Publication Number:
  US 20120001596A1
• Time in Patent Office: 721 Days
• Field of Search: 320/119, 320/116, 320/117, 320/125, 320/135, 320/137, 320/134, 320/136, 320/130, 320/121, 320/126, 320/127
• US Class Current: 320/125
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00038 using passive battery identification means, e.g. resistors or capacitors identification by mechanical connections H02J7/0045
• 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: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0036 using connection detecting circuits H02J7/0034 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 : Regulation of charging current or voltage
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries

Abstract

A method and system for charging multi-cell lithium-based batteries. In some aspects, a battery charger includes a housing, at least one terminal to electrically connect to a battery pack supported by the housing, and a controller operable to provide a charging current to the battery pack through the at least one terminal. The battery pack includes a plurality of lithium-based battery cells, with each battery cell of the plurality of battery cells having an individual state of charge. The controller is operable to control the charging current being supplied to the battery pack at least in part based on the individual state of charge of at least one battery cell.

Claims

1. A battery charger operable to charge a power tool battery having a plurality of Lithium-based battery cells, the battery charger comprising:

a charging circuit operable to provide a pulsed charging current to the power tool battery for at least a portion of a charging operation of the power tool battery; and

a controller operable to control the pulsed charging current provided to the power tool battery based at least in part on a comparison of an individual state of charge of at least one of the plurality of battery cells to at least one state of charge threshold value,

wherein controlling the pulsed charging current includes entering one of a defective power tool battery mode in which the pulsed charging current is interrupted and an indicator is correspondingly controlled to indicate the defective power tool battery mode, and entering a normal charge mode in which the pulsed charging current is provided to the power tool battery and the indicator is correspondingly controlled to indicate the normal charge mode, and

wherein the defective power tool battery mode and the normal charge mode are each entered based at least on part on the comparison of the individual state of charge of the at least one of the plurality of battery cells to the at least one state of charge threshold value.

2. The battery charger of claim 1, wherein the charging circuit is further operable to provide a second charging current to a second battery having a Nickel-Cadmium chemistry or a Nickel-Metal-Hydride chemistry.

3. The battery charger of claim 2, wherein the controller is operable to control the charging circuit to provide the pulsed charging current by a first charging algorithm to the power tool battery and the second charging current by a second charging algorithm to the second battery, the first charging algorithm being different than the second charging algorithm.

4. The battery charger of claim 1, wherein the power tool battery is configured to provide power to a hand-held power tool.

5. The battery charger of claim 1, wherein controlling the pulsed charging current includes entering a trickle charge mode in which the pulsed charging current is provided to the power tool battery and the indicator is correspondingly controlled to indicate the trickle charge mode.

6. The battery charger of claim 5, wherein the trickle charge mode is entered based at least in part on the comparison of the individual state of charge of the at least one of the plurality of battery cells to the at least one state of charge threshold value.

7. The battery charger of claim 1, wherein the battery charger is configured to receive the individual state of charge of the at least one of the plurality of battery cells from the power tool battery.

8. The battery charger of claim 1, wherein the controller is further operable to control the pulsed charging current by modifying at least one of a first period of time in which the charging current is being provided to the power tool battery at a predefined amplitude, and a second period of time in which the pulsed charging current is suspended.