Method and system for battery protection employing over-discharge control

• US 7,952,326 B2
• Filed: 02/17/2009
• Issued: 05/31/2011
• 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., Grzybowski, Dennis J., Meyer, Gary D., Zeiler, Jeffrey M.
• Primary Examiner(s): Tso; Edward
• Application Number:
  US12/372,015
• Publication Number:
  US 20090197152A1
• Time in Patent Office: 833 Days
• Field of Search: 320/107, 320/114, 320/115, 320/134, 320/136, 320/150, 320/153
• US Class Current: 320/114
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• 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 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 10/488 Cells or batteries combined with indicating means for external visualization of the condition, e.g. by change of colour or of light density
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/623 Portable devices, e.g. mobile telephones, cameras or pacemakers
• CPC Class Codes: H01M 10/6235 Power tools
• CPC Class Codes: H01M 10/6551 Surfaces specially adapted for heat dissipation or radiation, e.g. fins or coatings
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 50/202 : Casings or frames around the primary casing of a single cell or a single battery
• CPC Class Codes: H01M 50/211 : adapted for pouch cells
• 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 50/247 : specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers
• CPC Class Codes: H01M 50/284 : with incorporated circuit boards, e.g. printed circuit boards [PCB]
• CPC Class Codes: H01M 50/296 : characterised by terminals of battery packs terminals of batteries H01M50/543
• 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: H02H 7/18 : for batteries; for accumulators
• CPC Class Codes: H02J 7/00 : Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• 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 7/0014 : Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0029 : with safety or protection devices or circuits
• 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 7/0042 : characterised by the mechanical construction
• CPC Class Codes: H02J 7/0045 : concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/0063 : with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007 : Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/007182 : in response to battery voltage
• CPC Class Codes: H02J 7/007184 : in response to battery voltage gradient
• CPC Class Codes: H02J 7/007194 : of the battery
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries

Abstract

A method and system for battery protection. In some aspects, a battery pack configured to be interfaced with a power tool includes a housing, a cell, a controller, and a circuit. The circuit is operable to enable the controller to operate when the voltage supplied by the cell to the controller is below an operating voltage threshold of the controller.

Claims

1. A battery pack configured to be interfaced with a hand held power tool, the battery pack comprising:

a housing;

a locking assembly operable to lock the battery pack to the power tool, the locking assembly including an actuator;

at least three terminals including a positive terminal, a negative terminal, and a sense terminal;

a plurality of cells, each cell having a voltage, power being transferable between the cells and the power tool, each cell having a lithium-based battery chemistry, the cells being electrically connected to one another in a partial parallel arrangement and a partial series arrangement;

a battery identification resistor; and

a thermistor indicative of a battery pack temperature;

wherein

a controller is operable to control a function of the battery pack, the controller being external to the cells and being operable with a voltage at least one of equal to and greater than an operating voltage threshold, the cells being operable to selectively supply voltage to the power tool as a function of the state of a switch and the thermistor; and

the controller is operable to prevent the battery pack from entering an over-discharged state via the switch when the voltage supplied by the cells to the power tool is below a predetermined battery voltage threshold.

2. The battery pack of claim 1, wherein the predetermined battery voltage threshold is a remaining state of charge of the battery pack.

3. The battery pack of claim 1, further comprising a fuel gauge including a plurality of light-emitting diodes and a push-button switch.

4. The battery pack of claim 1, wherein the power tool is one of a circular saw and a driver drill.

5. The battery pack of claim 1, wherein the battery cells have a lithium manganese chemistry.