Lithium-based battery for a hand held power tool

• US 7,557,535 B2
• Filed: 08/07/2007
• Issued: 07/07/2009
• Est. Priority Date: 11/22/2002
• Status: Expired due to Term

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Scheucher, Karl F., Kubale, Mark A., Johnson, Todd W., Glasgow, Kevin L., Rosenbecker, Jay J., Zeiler, Jeffrey M., Grzybowski, Dennis J., Meyer, Gary D.
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US11/834,820
• Publication Number:
  US 20080185993A1
• Time in Patent Office: 700 Days
• Field of Search: 320/106, 320/110, 320/112, 320/114
• US Class Current: 320/112
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 50/213 adapted for cells having curved cross-section, e.g. round or elliptic H01M50/209, H01M50/216 take precedence
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• 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 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• 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 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for conducting an operation including a power tool battery pack. The battery pack can include a housing, a first cell supported by the housing and having a voltage, and a second cell supported by the housing and having a voltage. The battery pack also can be connectable to a power tool and be operable to supply power to operate the power tool. The method can include discharging one of the first cell and the second cell until the voltage of the one of the first cell and the second cell is substantially equal to the voltage of the other of the first cell and the second cell.

Claims

1. An electrical combination comprising:

an electrical motor of a handheld power tool;

a trigger switch engageable by a user of the handheld power tool;

an electrical circuit; and

a plurality of battery cells, the battery cells having a lithium based chemistry and a combined voltage of at least substantially 28 volts, wherein the plurality of battery cells is capable of producing an average discharge current greater than or equal to approximately 20 amps,

wherein the trigger switch is coupled to the motor such that engagement of the trigger switch enables the electrical motor to draw power through the electrical circuit from the plurality of battery cells.

2. The electrical combination as set forth in claim 1, wherein the battery cells have a lithium-manganese chemistry

3. The electrical combination as set forth in claim 1, wherein the battery cells have a spinel chemistry.

4. The electrical combination as set forth in claim 1, wherein the plurality of battery cells include seven battery cells.

5. The electrical combination as set forth in claim 1, wherein each of the plurality of battery cells has a nominal voltage of approximately 4.2 volts.

6. The electrical combination as set forth in claim 1, further comprising a protection circuit configured to protect at least one component of the electrical combination.

7. The electrical combination as set forth in claim 6, wherein the electrical circuit includes the protection circuit.

8. The electrical combination as set forth in claim 1, further comprising a power tool housing for supporting the electrical motor, the trigger switch, and the electrical circuit.

9. The electrical combination as set forth in claim 8, further comprising a battery housing for supporting the plurality of battery cells.

10. The electrical combination as set forth in claim 9, wherein the battery housing is removably coupled to the power tool housing.

11. The electrical combination as set forth in claim 1, wherein the electrical motor, the trigger switch, the electrical circuit, and the plurality of battery cells are components of one of a driver drill and a circular saw.

12. The electrical combination as set forth in claim 1, wherein the handheld power tool is one of a driver drill and a circular saw.

13. An electrical combination comprising:

an electrical motor of a hand held power tool;

a trigger switch engageable by a user of the handheld power tool;

an electrical circuit; and

a plurality of battery cells, the battery cells having a lithium based chemistry and a combined voltage of at least substantially 28 volts, wherein the plurality of battery cells has an ampere-hour capacity of approximately 3.0 ampere-hours,

wherein the trigger switch is coupled to the motor such that engagement of the trigger switch enables the electrical motor to draw power through the electrical circuit from the plurality of battery cells.