Battery pack having a sensor activated off switch

• US 8,410,756 B2
• Filed: 08/23/2010
• Issued: 04/02/2013
• Est. Priority Date: 09/04/2009
• Status: Expired due to Fees

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Sakakibara, Kazuyuki, Murata, Hiroshi, Matsunaga, Yutaka, Goto, Munetoshi
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US12/805,887
• Publication Number:
  US 20100320969A1
• Time in Patent Office: 953 Days
• Field of Search: 320/118
• US Class Current: 320/118
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• 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 50/244 Secondary casings; Racks; Suspension devices; Carrying devices; Holders characterised by their mounting method
• CPC Class Codes: H01M 50/247 specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers
• CPC Class Codes: H01M 50/271 Lids or covers for the racks or secondary casings
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack is provided with a plurality of battery modules; a pack main body that removably receives the plurality of battery modules; a movable member that prohibits the plurality of battery modules from being attached to and removed from the pack main body at a first position; at least one sensor that detects whether the movable member is located at the first position or not; and a controller that performs at least one predetermined processing based on detection by the at least one sensor.

Claims

1. A battery pack configured to supply electric power to an electric power tool, the battery pack comprising:

a plurality of battery modules, each comprising at least one battery cell;

a pack main body configured to;

removably receive the plurality of battery modules, electrically connect the plurality of battery modules, and output electric power from the plurality of battery modules to the electric power tool;

a movable member configured to;

be movable to and from a first position with respect to the pack main body, and prohibit the plurality of battery modules from being attached to and removed from the pack main body when the movable member is at the first position;

at least one sensor configured to detect whether the movable member is at the first position or not;

at least one switch electrically connected in series with the at least one battery cell of the battery module; and

a controller coupled with the at least one sensor and the at least one switch, and configured to turn off the at least one switch when detection by the at least one sensor indicates movement of the movable member from the first position.

2. The battery pack as in claim 1, wherein

the at least one switch includes a first switch disposed on a wiring that conducts discharging current from the at least one battery cell, and

the controller is configured to turn off the first switch for prohibiting the plurality of battery modules from being discharged by the electric power tool when the detection by the at least one sensor indicates movement of the movable member from the first position.

3. The battery pack as in claim 1, wherein

the at least one switch includes a second switch disposed on a wiring that conducts charging current to the at least one battery cell of the battery module, and

the controller is configured to turn off the second switch for prohibiting the plurality of battery modules from being charged by an external power supply when the detection by the at least one sensor indicates movement of the movable member from the first position.

4. The battery pack as in claim 1, wherein

the at least one switch includes a third switch disposed on a wiring that electrically connects the at least one battery cell of one battery module in series with the at least one battery cell of another battery module, and

the controller is configured to turn off the third switch for electrically disconnecting the plurality of battery modules attached to the pack main body when the detection by the at least one sensor indicates movement of the movable member from the first position.

5. The battery pack as in claim 1, wherein

the plurality of battery modules each comprises the at least one switch electrically connected in series with the at least one battery cell;

and

the controller is configured to turn off the at least one switch of at least one of the plurality of battery modules when the detection by the at least one sensor indicates movement of the movable member from the first position.

6. The battery pack as in claim 5, wherein the controller is configured to turn on the at least one switch after the detection by the at least one sensor indicates movement of the movable member to the first position.

7. The battery pack as in claim 6, wherein the controller is configured to keep turning off the at least one switch for a predetermined delay time after the detection by the at least one sensor indicates the movement of the movable member to the first position.

8. The battery pack as in claim 1, wherein the controller is configured to perform a check process for checking a state of degradation of the at least one battery cell disposed in each of the plurality of battery modules when the detection by the at least one sensor indicates movement of the movable member from the first position.

9. The battery pack as in claim 8, wherein

the plurality of battery modules each comprises a detector configured to detect at least one of voltage and current of the at least one battery cell thereof and a discharging circuit configured to be electrically connected to and discharge the at least one battery cell thereof in accordance with an instruction from the controller, and

the controller is configured to use the detectors and the discharging circuits of the plurality of battery modules in the check process.

10. The battery pack as in claim 1, wherein the controller comprises a memory unit configured to memorize at least a part of the detection by the at least one sensor, and

the controller is configured to perform a balance process for charging or discharging at least one of the plurality of battery modules so as to equalize states of charge among the plurality of battery modules.

11. The battery pack as in claim 1, wherein the controller comprises a memory unit and is configured to:

memorize a first detection flag in the memory unit when the detection by the at least one sensor indicates movement of the movable member from the first position,

perform a balance process for charging or discharging at least one of the plurality of battery modules so as to equalize states of charge among the plurality of battery modules at a predetermined timing when the first detection flag is memorized in the memory unit, and

erase the first detection flag from the memory unit upon performing the balance process.

12. The battery pack as in claim 1, wherein the controller comprises a memory unit and is configured to:

memorize a first detection flag in the memory unit when the detection by the at least one sensor indicates movement of the movable member from the first position,

perform a balance process for charging or discharging at least one of the plurality of battery modules so as to equalize states of charge among the plurality of battery modules in a process of charging of the battery pack when the first detection flag is memorized in the memory unit, and

erase the first detection flag from the memory unit upon performing the balance process.

13. The battery pack as in claim 10, wherein

the plurality of battery modules each comprises a detector configured to detect at least one of voltage and current of at least one of the plurality of battery cells thereof, and a discharging circuit configured to electrically connect to and discharge the plurality of battery cells thereof in accordance with an instruction from the controller, and

the controller is configured to use the detector and the discharging circuit of the at least one of the plurality of battery modules in the balance process.

14. The battery pack as in claim 13, wherein the controller is configured to further perform a check processing for checking a state of degradation of the plurality of battery cells disposed in each of the plurality of battery modules with a use of the detectors and the discharging circuits of the plurality of the battery modules.

15. The battery pack that supplies electric power to an electric power tool, the battery pack comprising:

a plurality of battery modules, each comprising at least one battery cell;

a pack main body configured to;

removably receive the plurality of battery modules, electrically connect the plurality of battery modules, and output electric power from the plurality of battery modules to the electric power tool;

an openable cover disposed on the pack main body and configured to at least partly screen the plurality of battery modules when the openable cover is closed;

at least one sensor configured to detect whether the openable cover is closed or not; and

at least one switch electrically connected in series with the at least one battery cell of the battery module; and

a controller coupled with the at least one sensor and the at least one switch, and configured to turn off the at least one switch when detection by the at least one sensor indicates that the openable cover is unclosed.