Rechargeable battery devices

• US 7,091,699 B2
• Filed: 04/01/2004
• Issued: 08/15/2006
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Sakakibara, Kazuyuki, Mori, Tatsuki, Fukumoto, Masaaki
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/816,583
• Publication Number:
  US 20040239293A1
• Time in Patent Office: 866 Days
• Field of Search: 320/DIG.21, 320/132, 320/106, 340/636.1
• US Class Current: 320/132
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Battery pack 10 may include rechargeable battery 12 and remaining capacity indicating circuit 14 for indicating the remaining capacity of the battery 12. Remaining capacity indicating circuit 14 may be coupled to the battery 12 via first switch SW1. When first switch SW1 is turned ON, a current flows from battery 12 to remaining capacity indicating circuit 14. When the first switch SW1 is turned OFF, the current flowing from battery 12 to remaining capacity indicating circuit 14 is turned OFF. The first switch SW1 may be coupled to first voltage detecting circuit (R2, R3) for detecting the voltage of battery 12. When the voltage that is being detected of battery 12 falls below a first predetermined value, first switch SW1 is turned off. Battery pack 10 may further include cut-off circuit (SW2, R4, R5) that cuts off the flow of current from battery 12 to first voltage detecting circuit (R2, R3) when first switch SW1 has been turned OFF.

Claims

1. A battery pack comprising:

a rechargeable battery,

means for indicating a remaining capacity of the battery, wherein the indicating means is coupled to the battery, wherein the indicating means utilizes power supplied from the battery, thereby indicating the remaining capacity of the battery,

a first switch electrically connecting and disconnecting the battery with the indicating means,

a first voltage detecting circuit coupled to the first switch and the battery, wherein the first switch is turned off when the battery voltage detected by the first voltage detecting circuit falls below a first predetermined value,

a cut-off circuit coupled to the first voltage detecting circuit, wherein the cut-off circuit cuts off the flow of current from the battery to the first voltage detecting circuit when the first switch has been turned off.

2. A battery pack as in claim 1, wherein the cut-off circuit comprises:

a second switch electrically connecting and disconnecting the battery with the first voltage detecting circuit,

a second voltage detecting circuit coupled to the first and second switches, wherein the second switch is turned off when the voltage detected by the second voltage detecting circuit falls below a second predetermined value, wherein the flow of current from the battery to the second voltage detecting circuit stops when the first switch has been turned off.

3. A battery pack as in claim 2, wherein the first voltage detecting circuit comprises two resistors that divides the voltage from the battery, wherein the battery pack further comprises:

a first terminal coupled to a plus pole of the battery,

a second terminal coupled to a minus pole of the battery,

a third terminal coupled to junctions of the two resistors of the first voltage detecting circuit.

4. A battery pack as in claim 3, wherein the second voltage detecting circuit comprises two resistors that divides the voltage from the battery, wherein the battery pack further comprises a fourth terminal coupled to junctions of the two resistors of the second voltage detecting circuit.

5. A battery pack as in claim 4, wherein the battery pack is arranged and constructed to be attached to a power tool, and the battery pack supplies power to the power tool via the first and second terminals, wherein the battery pack further comprises means for outputting a signal to the junctions of the two resistors of the first voltage detecting circuit or to the junctions of the two resistors of the second voltage detecting circuit, wherein the outputting means outputs the first signal when the power tool is being supplied with power from the battery, and outputs a second signal when the power tool is not being supplied with power from the battery, wherein the voltage of the second signal is smaller than the voltage of the first signal.

14. The battery pack of claim 1 wherein the means for indicating comprises an LED display.

6. An apparatus comprising:

a rechargeable battery,

means for indicating a remaining capacity of the battery, wherein the indicating means is coupled to the battery, wherein the indicating means utilizes power supplied from the battery, thereby indicating the remaining capacity of the battery,

a first switch electrically connecting and disconnecting the battery with the indicating means,

a first voltage detecting circuit coupled to the first switch and the battery, wherein the first switch is turned off when the battery voltage detected by the first voltage detecting circuit falls below a first predetermined value,

a cut-off circuit coupled to the first voltage detecting circuit, wherein the cut-off circuit cuts off the flow of current from the battery to the first voltage detecting circuit when the first switch has been turned off.

7. An apparatus as in claim 6, wherein the cut-off circuit comprises:

a second switch electrically connecting and disconnecting the battery with the first voltage detecting circuit,

a second voltage detecting circuit coupled to the first and second switches, wherein the second switch is turned off when the voltage detected by the second voltage detecting circuit falls below a second predetermined value, wherein the flow of current from the battery to the second voltage detecting circuit is stopped when the first switch has been turned off.

8. An apparatus as in claim 7, wherein the first voltage detecting circuit comprises two resistors that divides the voltage from the battery, wherein the apparatus further comprises a first terminal coupled to junctions of the two resistors of the first voltage detecting circuit.

9. An apparatus as in claim 7, wherein the second voltage detecting circuit comprises two resistors that divides the voltage from the battery, wherein the apparatus further comprises a second terminal coupled to junctions of the two resistors of the second voltage detecting circuit.

15. The apparatus of claim 6 wherein the means for indicating comprises an LED display.

10. A battery pack comprising:

a rechargeable battery,

an indicator that displays remaining capacity of the battery, wherein the indicator is coupled to the battery, wherein the indicator utilizes power supplied from the battery, thereby indicating the remaining capacity of the battery,

a first switch electrically connecting and disconnecting the battery with the indicator,

a first voltage detecting circuit coupled to the first switch and the battery, wherein the first switch is turned off when the battery voltage detected by the first voltage detecting circuit falls below a first predetermined value,

a cut-off circuit coupled to the first voltage detecting circuit, wherein the cut-off circuit cuts off the flow of current from the battery to the first voltage detecting circuit when the first switch has been turned off.

11. The battery pack of claim 10 wherein the indicator comprises a LED display.

12. An apparatus comprising:

a rechargeable battery,

an indicator circuit that indicates remaining capacity of the battery, wherein the indicator circuit is coupled to the battery, wherein the indicator circuit utilizes power supplied from the battery, thereby indicating the remaining capacity of the battery,

a first switch electrically connecting and disconnecting the battery with the indicator circuit,

a first voltage detecting circuit coupled to the first switch and the battery, wherein the first switch is turned off when the battery voltage detected by the first voltage detecting circuit falls below a first predetermined value,

a cut-off circuit coupled to the first voltage detecting circuit, wherein the cut-off circuit cuts off the flow of current from the battery to the first voltage detecting circuit when the first switch has been turned off.

13. The apparatus of claim 12 wherein the indicator circuit comprises a LED display.