WO2009085915A2

WO2009085915A2 - Method and apparatus for bi-contact battery-charger system

Info

Publication number: WO2009085915A2
Application number: PCT/US2008/087365
Authority: WO
Inventors: Mohd Hisham Muddin B. Che At; Nasrudin B. Abdul Muthalib; Jaya B. Rao
Original assignee: Motorola, Inc.
Priority date: 2007-12-21
Filing date: 2008-12-18
Publication date: 2009-07-09
Also published as: MY144094A; WO2009085915A3

Abstract

A method and apparatus for charging a rechargeable battery is disclosed. The method and apparatus include providing a battery charger with two terminals and wherein a microprocessor within the battery charger is operable to switch the positive terminal from a charging function to a data transfer function for the purpose of receiving charging parameters and temperature from a battery being charged. The method and apparatus further includes providing a battery responsive to the charger wherein the battery has a positive terminal able to transition from a charging function to a data transfer function in response to the charger operations.

Description

METHOD AND APPARATUS FOR BI-CONTACT BATTERY-CHARGER SYSTEM

Field of the Invention

[0001] The present invention relates generally to rechargeable batteries. The invention relates, more particularly, to a battery charger system.

Background

[0002] A rechargeable battery, also known as a storage battery, is usually a group of two or more secondary cells. These rechargeable batteries can be restored to full charge by the application of electrical energy. In other words, they are electrochemical cells in which the electrochemical reaction that releases energy is readily reversible. Rechargeable electrochemical cells are a type of accumulator. The cells come in many different designs and with different chemicals. Rechargeable batteries are used for lower power applications such as automobile starters, portable consumer devices, tools, and uninterruptible power supplies. Additional possible applications in an emerging environment include hybrid vehicles and electric vehicles. Other future applications include a proposed use of rechargeable batteries for load leveling; where the battery would store baseline electric power for use during peak load periods and for renewable energy uses, such as storing power generated from photovoltaic arrays during the day and for use at night. During charging, the positive active material is oxidized, producing electrons, and the negative material is reduced, consuming electrons. These electrons constitute the current flow in the external circuit. An electrolyte may serve as a simple buffer for ion flow between the electrodes, or it may be an active participant in electrochemical reaction.

[0003] The active components of a secondary cell are the chemicals that make up the positive and negative active materials, and the electrolyte. The positive and negative elements are made up of different materials, with the positive element exhibiting a reduction potential and the negative element having an oxidation potential. The sum of these potentials is a standard cell potential or voltage. When referring to non-rechargeable batteries, also referred to as primary cell batteries, the positive and negative electrodes are known as the cathode and anode, respectively. Although this convention is sometimes carried through to rechargeable systems, this practice can lead to confusion. In rechargeable cells, the positive electrode is the cathode during discharge and the anode during charge, and vice versa for the negative electrode.

[0004] Since many rechargeable batteries use different factor components (i.e., the chemicals used to make up the positive and negative active materials), the charging characteristics for each type of rechargeable battery tend to be different. These charging characteristics include the amount of time required to charge the battery, the temperature range at which the battery can be charged, and the potential for damage resulting from overcharge or complete discharge of the battery. Therefore, a battery charger must either be designed for use with a particular rechargeable battery, or be designed for use to adapt to the characteristics of the different types of rechargeable batteries. Ideally the battery charger should be able to determine the charging characteristics of the battery to be charged both prior to charging and during charge. Since various batteries can be damaged by overcharging or charging outside of the designed characteristics, an ideal battery charger must be able to sense the present characteristics of the battery being charged. Therefore, present battery chargers that sense various battery characteristics, prior to and during charging of a battery require at least four terminals to charge a battery. The terminals include a positive terminal or cathode, a negative terminal or anode, a data terminal and a temperature sensing terminal. The rechargeable batteries must, additionally, have at least four terminals to communicate with both a positive and negative terminal, but also with the battery charger and be charged by the battery charger. Therefore, battery charger systems, and the rechargeable batteries, must be manufactured with the additional terminals for data and temperature. If the data and temperature terminals could be eliminated, manufacturing costs savings could be realized. What is needed is a system and method to recharge a battery using only the positive and negative terminals used to provide the electrical energy for charging the battery, yet still be able to sense data and temperature characteristics, while maintaining or improving electrostatic discharge immunity.

Brief Description of the Figures

[0005] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

[0006] FIG. 1 is an exemplary prior art battery comprising at least four contacts;

[0007] FIG. 2 is an exemplary block diagram of a system for charging a battery using two interface contacts in accordance with some embodiments of the present invention;

[0008] FIG. 3 A is a block diagram illustrating more detailed components of an exemplary charger and an exemplary battery in accordance with embodiments of the present invention;

[0009] FIG. 3B is an exemplary block diagram of a switching means for use in a rechargeable battery in accordance with some embodiments of the present invention;

[0010] FIG. 4 is an exemplary flow chart for charging a rechargeable battery in accordance with some embodiments of the present invention; and

[0011] FIG. 5 is an exemplary battery utilizing two charger terminals in accordance with embodiments of the present invention.

[0012] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

Detailed Description

[0013] Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to bi-contact battery-charger system. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0014] In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises", "comprising", "includes", "including" or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises ...a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0015] It will be appreciated that embodiments of the invention described herein may be comprised of one or more conventional processors and unique stored program instructions that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of bi-contact battery-charger system described herein. The non-processor circuits may include, but are not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method to perform bi-contact battery-charger system. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.

[0016] A system for charging a rechargeable battery is disclosed. The system includes providing a battery charger with two terminals wherein a microprocessor within the battery charger is operable to switch the positive terminal from a charging function to a data transfer function. The system also includes a battery with two terminals responsive to the charger microprocessor wherein the positive terminal on the battery is used for both receiving a charge from the battery charger and transmitting data to the battery charger microprocessor.

[0017] A method for charging a rechargeable battery is disclosed. The method includes providing a battery charger with two terminals wherein a microprocessor within the battery charger is operable to switch the positive terminal from a charging function to a data transfer function. The method includes the charger able to determine a battery type and able to transition a positive charging terminal from a charging function to a data transfer function for the purpose of receiving charging parameters including percentage charge and temperature from a battery being charged. The method further includes providing a battery responsive to the charger for providing a terminal to receive a charge from the charger as well as providing charging data to the charger.

[0018] Referring now to FIG. 1, a prior art rechargeable mobile phone battery with four charging terminals is illustrated. The battery 100 can be any type of rechargeable battery as is presently known in the art. The battery 100 may have a negative polarity charging terminal 102, a data charging terminal 104, a charger thermistor terminal 106 and a positive charging terminal 108. The data charging terminal 104 transmits battery charging parameter data for the battery 100. The charge thermistor terminal 106 transmits a signal related to the present temperature of the battery 100 before and during the charge function. Additionally, the battery 100 may have three separate device terminals. The device terminals can be a negative device terminal 110, a positive device terminal 114 and a device data terminal 112. The device terminals provide power from the battery 100 to the, for example, mobile phone device. Artisans of skill will appreciate that although the terminals are shown on opposite sides of a battery, the terminals are not limited to be on any particular side of the battery. Additionally, the shape of the battery 100 is exemplary and the battery 100 is not limited to a square shape. The device data terminal 112 transmits data, such as current charge percentage, from the battery 100 to a device (not shown) to which the battery 100 is connected. The negative device terminal 110 and positive device terminal 114 conduct electricity from the battery 100 to the device. The negative charging terminal 102 and positive charging terminal 108 comprise a pair of charging interfaces that complete a charging circuit by conducting electricity between a charger and the battery.

[0019] Referring now to FIG. 2, an exemplary block diagram of a charger and the battery in accordance with embodiments of the present invention is illustrated. The battery 200 has two interfaces: a charging interface 206 for connection with a battery charger 250; and a device interface 216 for connection with a device (not shown). The charging interface 206 comprises a positive/data charging terminal 202 and a negative charging terminal 204. The device interface 216 comprises a negative terminal 210, a data terminal 212 and a positive terminal 214. A battery cell 220 is connected between the negative terminal 210 and the positive terminal 214. The battery cell 220 can include battery protection circuitry (not specifically shown) and an active component. The battery cell 220, i.e., the active component, can be Lead-acid; Nickel-iron (Ni-iron); Nickel-cadmium (Ni-cadmium); Nickel Metal Hydride (NiMH); Nickel-zinc (Ni-zinc); Lithium ion (Li-ion); Li-ion polymer; Li-ion Phosphate; Li-sulfur; Nano Titante; Thin Film Lithium; Zinc bromide; Sodium-sulfur (NaS); Molten salt; Super iron; Silver zinc; rechargeable alkaline; a non-chemical such as Iron-Sulfur (FeS); or substantially any type of rechargeable battery presently in existence or discovered in the future.

[0020] A charge data switch 224 is connected between the positive/data charging terminal 202 (hereinafter "+/data charging terminal") and the positive terminal 214. The battery 200 also includes a fuel gauge Integrated Circuit (hereinafter "fuel gauge IC") with temperature sensor 222. The charge data switch 224 enables the battery 200 to be charged via +/data charging terminal 202 or transmit data via +/data charging terminal 202. The fuel gauge IC 222 is connected on one side to the +/data charging terminal 202 and on the other side to the positive terminal 214. The fuel gauge IC 222 is further connected on a lower side to the negative charging terminal 204. The fuel gauge IC 222 also transmits data via data terminal 212 to the connected device. As such, the fuel gauge IC 222 can send charging and temperature data via the +/data charging terminal 202 to the battery charger 250, or the fuel gauge IC 222 can send charge data, such as percent of charge remaining, via data line 212 to a device connected to the battery 200. The negative charging terminal 204 is further directly connected to the negative terminal 210.

[0021] The battery charger 250 has two charging interfaces (e.g., charging terminals, or charging contacts) 252 and 258. The first interface is a positive/data terminal (hereinafter "+/data terminal") 258. The second interface is a negative terminal 252. The interfaces 252 and 258 connect the charger 250 to the battery 200 via the battery charging interface 206. The +/data terminal 258 removably connects to, or contacts, the +/data charging terminal 202 and the negative terminal 252 removably connects to, or contacts, the negative charging terminal 204. The battery charger 250 includes a charger circuit 260. The charger circuit 260 can be any type of charger circuit as is known in the art such that it provides energy to be transmitted to the battery for charging of the battery. The battery charger 250 further includes a charge enable switch 280 (hereinafter "C/E switch") connected between the charger circuit 260 and the +/data terminal 258. A microprocessor 270, connected to the C/E switch 280 and to the +/data terminal 258, controls the C/E switch 280. The microprocessor 270 includes a storage means (not shown) for storing software instructions that enable the microprocessor 270 to switch the C/E switch 280 from a closed position to an open position in which the C/E switch 280 opens a circuit between charger circuit 260 and +/data terminal 258. The storage means can be any computer readable medium, for example, the storage means can be any electronic, magnetic, electromagnetic, optical, electro-optical, electro-mechanical, and/or other physical device that can contain, store, communicate, propagate, or transmit a computer program, software, firmware, or data for use by the microprocessor or other computer-related system or method. When the charge microprocessor 270 opens the C/E switch 280, such that the circuit between the charger circuit 260 and the +/data terminal 258 is open, the charger microprocessor 270 may then receive data via the +/data terminal 258. Therefore, when the charger microprocessor 270 opens the C/E switch 280, such that data can be received via +/data terminal 258, data can be received from the battery 200 when it is connected to the charger 250. By opening the C/E switch 280, the charger microprocessor 270 further establishes a condition whereby the charge data switch 224, and ultimately the battery 200, is switched to enable a data transfer via the +/data charging terminal 202 of the battery 200. As such, switching the C/E switch 280 to an open position results in the switching of the +/data charging terminal 202 from a charging terminal to a data transfer terminal. Thereafter, the fuel gauge IC 222 can transmit data via the +/data charging terminal 202 to the +/data terminal 258 to the charger microprocessor 270. The C/E switch 280 may be opened and closed by the charger microprocessor 270 at predetermined times and/or on a periodic basis during the battery charging process so that the charger microprocessor 270 can receive battery temperature data or signals as well as battery charge instructions or requirements.

[0022] Referring now to FIG. 3 A, a more detailed block diagram of an exemplary charger and battery in accordance with embodiments of the present invention is illustrated. The battery 200 has a charger interface 206 comprising interface terminals 202 and 204 for connection to the charger 250. The battery 200 also has a discharging interface 216 comprising three interface terminals: positive device terminal 210, data device terminal 212 and negative device terminal 214 for connection to a device (not shown). The charging interface 206 of the battery 200 has a negative charging terminal 204 and a +/data charging terminal 202. The battery 200 includes a fuel gauge IC with embedded temp sensor 222. The fuel gauge IC 222 has a node connected to the +/data charging terminal 202. The fuel gauge IC 222 is also connected via another node to the negative terminal 204 as well as the negative device terminal 210. When the battery 200 is connected to a charger 250, a charge current is passed through the +/data charging terminal 202 and through a Schottky diode 326 to a battery cell 320. The battery cell 320 can include a battery protection circuitry 327 with switching means (described in detail herein below with respect to Fig 3B). The battery cell 320 can be Lead- acid; Nickel-iron (Ni-iron); Nickel-cadmium (Ni-cadmium); Nickel Metal Hydride (NiMH); Nickel-zinc (Ni-zinc); Lithium ion (Li-ion); Li-ion polymer; Li- ion Phosphate; Li-sulfur; Nano Titante; Thin Film Lithium; Zinc bromide; Sodium-sulfur (NaS); Molten salt; Super iron; Silver zinc; rechargeable alkaline; and a non-chemical such as Iron-Sulfur (FeS). The battery cell 320 is further may connect at a positive electrode at the positive device terminal 214 and to a negative electrode at the negative device terminal 210. Additionally, the battery cell 320 is connected to the fuel gauge IC 222 at another node of the fuel gauge IC 222, such that the fuel gauge IC 222 can communicate a present state of battery charge via a data line and the data terminal 212 to the connected device (not shown). A charge switching means 324 (see also Fig. 3B) is also connected through a Schottky diode 328 to the +/data charging terminal and node 202.

[0023] The Schottky diode, named after German physicist Walter H. Schottky, is a semiconductor diode with a low forward voltage drop and a very fast switching action. As with other diodes, Schottky diodes have an anode and a cathode. These diodes are typically used for discharge protection for lead acid batteries and switch mode power supplies. While standard silicon diodes have a forward drop voltage of about .6 volts and Germanian diodes have a .2 drop, Schottky diodes voltage drop at forward biases of around 1 milliamp is in the range of .15 volts to .46 volts, which makes them useful in voltage clamping applications and prevention of transistor saturation. This is due to the higher density in the Schottky diode. When the battery 200 is not connected to the charger 250, the Schottky diode 328 isolates a data switching means 322 from the fuel gauge IC 222. The data switching means 322 can be comprised of additional switches connected in series wherein the switches can be micro switches or other type of transistors such as Bipolar Junction Transistors ("BJTs"), JFETs, NFETs, Metal- Oxide-Semiconductor Field-Effect Transistor ("MOSFETS"), Metal- Semiconductor Field-Effect Transistor ("MESFET"), Heterostructure FET ("HFET"), Modulation-Doped Field Effect Transistor ("MODFET"), Insulated- Gate Bipolar Transistor (IGBT), and a FREDFET. Additionally, the Schottky diode 326, when the battery 200 is connected to the charger 250, provides a reverse discharge protection to the battery cell 320. [0024] When the battery 200 is not connected to the charger 250, the fuel gauge IC 222 opens the charge switching means 324. The charge switching means 322 can be micro switch or other type of transistor such as a Bipolar Junction Transistors ("BJTs"), JFETs, NFETs, Metal-Oxide-Semiconductor Field-Effect Transistor ("MOSFETS"), Metal-Semiconductor Field-Effect Transistor ("MESFET"), Heterostructure FET ("HFET"), Modulation-Doped Field Effect Transistor ("MODFET"), Insulated-Gate Bipolar Transistor (IGBT), and a FREDFET. Additionally, when the battery 200 is connected to the device (not shown) and in discharge, i.e., the battery 200 is powering the device, the data switching means 322 closes. Therefore, when the charge switching means 324 is opened and data switching means 322 is closed, then the fuel gauge IC 222 can communicate data via the data terminal 212 with the connected device (not shown).

[0025] Battery charger 250 has a +/data terminal 258 for connection to a +/data charging terminal 202 of the battery 200. The battery charger 250 also has a negative charge terminal 252 for connection to the negative terminal 204 of the battery 200. The charger 250 contains charger circuitry 260 connected to a charger microprocessor 270. The charger circuitry 260 has a node connected to the +/data terminal 258 via the C/E switch 280. The C/E switch 280 can be an N- type field effect transistor (hereinafter "FET"). The charger microprocessor 270 is also connected through a control line 272 to a gate node of the C/E switch 280. The microprocessor 270 includes a storage means (not shown) for storing software instructions that enable the microprocessor to switch the C/E switch 280. The control line 272 connection from the microprocessor 270 to the C/E switch 280, enables the microprocessor 270 to control the C/E switch 280. The charger microprocessor 270 is also data connected to the data terminal 258 via data line 274 and through the C/E switch 280. Two zener diodes 290 and 292 are connected between the data line 274 and the negative terminal 252 to provide electrostatic discharge protection. A zener diode is a type of diode that permits current to flow in a forward direction like a normal diode, but also in reverse direction if the voltage is larger than the breakdown voltage known as the "zener knee voltage" or the zener voltage.

[0026] When the battery 200 is connected to the charger 250, the charge switching means 324 is closed and the data switching means 322 is opened. Therefore, no data communication can occur between the fuel gauge IC 222 and the device (not shown) connected to the battery 200. Data communications, when the battery 200 is connected to the charger 250, are prevented in this manner so as to help avoid data communication errors (i.e., data clash) when the charger microprocessor 270 is communicating with the fuel gauge IC 222. Additionally, whenever the charger microprocessor 270 attempts to read the fuel gauge IC 222, software in the charger microprocessor 270 instructs the microprocessor 270 to switch the C/E switch 280 to an open state. Switching the C/E switch 280 to an open state occurs whenever the charger microprocessor 270 starts an operation to read data from fuel gauge IC 222 of the battery 200. Thereafter, the microprocessor 270 will read the data (i.e., receive the data from) in the fuel gauge IC 222. The initial state of the C/E switch 280 is off (i.e., in an open state). Prior to charging the battery 200, and in order to prevent battery damage, the charger 250 must determine that the battery 200 is an authorized battery; determine what the present charge state of the battery is; and receive the battery charge or charging parameters as well as the temperature of the battery cell. Therefore, the C/E switch 280 is initially off (i.e., open) so the microprocessor 270 may receive the data prior to the charging operation.

[0027] Referring now to Fig. 3B, an exemplary block diagram of a charge data switch 224 of battery 200 is illustrated. As stated herein above with respect to Fig. 3a, the Schottky diode 326 is connected on the anode to the +/data charging terminal 202. The Schottky diode 326 is connected on the cathode to a resistor 330. The resistor 330 is a pull up resistor for the charge data switch 224. The resistor 330 is further connected to a first switching means 322 (i.e., the data switching means 322 of Fig. 3A). The first switching means 322 comprises a first FET 332 and a second FET 334. The first FET 332 and second FET 334 work in conjunction to switch the data transmission between the fuel gauge IC 222 and a connected device (not shown) via the data terminal 212. The pull up resistor 330 is connected to a gate node of the first FET 332. The pull up resistor 330 is additionally connected to a gate node of the second FET 334. Therefore, when the battery 200 is connected to the charger and being charged, the voltage on the cathode of the Schottky diode 326 is high enough to cause the pull up resistor 330 to pull the voltage at the gate of the first FET 332 and at the gate of the second FET 334 high. When the voltage at the gate of the first FET 332 and the voltage at the gate of the second FET 334 are high, the FETs 332, 334 transition from an off state (i.e. open) to an on state (i.e. on), thereby enabling the fuel gauge IC 222 to transmit data via the first FET 332 and the second FET 334 to the data terminal 212.

[0028] The charge data switch 224 may also have a second switching means (i.e., the charge switching means 324 of Fig 3A). The second switching means can include an N-type FET 324, a micro switch or other type of transistor such as Bipolar Junction Transistor ("BJT"), JFET, Metal-Oxide-Semiconductor Field- Effect Transistor ("MOSFETS"), Metal-Semiconductor Field-Effect Transistor ("MESFET"), Heterostructure FET ("HFET"), Modulation-Doped Field Effect Transistor ("MODFET"), Insulated-Gate Bipolar Transistor (IGBT), and a FREDFET. A gate node of the switching means FET 324 is connected to the cathode of the second Schottky diode 328. The Schottky diode 328 is connected on its anode to the +/data charging terminal 202. Additionally, connected to the gate of the second switching means FET 324 is a pull down resistor 336 and a voltage stabilizing capacitor 340. The capacitor 340 stabalizes the voltage at the gate of the second switching means FET 324; removes noise at the at the gate of the second switching means FET 324; and helps protect the second switching means FET 324 form static or voltage spikes. The pull down resistor 336 is connected from the gate of the second means FET 324 to the negative terminal 210. The voltage stabilizing capacitor 340 is connected between the gate of the second switching means FET 324 and the negative terminal 210. Therefore, when the battery 200 is connected to the charger 250 and the battery 200 is in a charge mode (i.e., the battery 200 is being charged by the charger 250), the voltage on the cathode of the Schottky diode 328 is high; therefore causing the pull down resistor 336 to keep the voltage on the gate of the second switching means FET 324 high. When the voltage on the gate of the second switching means FET 324 is high, the gate saturates and closes, essentially connecting the drain node to the source node. As such, the voltage at the drain node equals the voltage at the source node. Since a drain node of the second switching means FET 324 is also connected to the gate nodes of the first switching means first FET 332 and second FET 334, when the second switching means FET 324 saturates and closes, the voltage of the gates of the first FET 332 and second FETs 334 go to a low voltage (i.e., a voltage below the threshold voltage for the FETs), thus opening these two FETS 332 and 334. Therefore, no data transmissions can occur between the fuel gauge IC 222 and connected device (not shown).

[0029] When the battery 200 is not connected to the charger 250, the fuel gauge IC 222 turns the second switching means FET 324 off. Additionally, when the battery 200 is connected to the device (not shown) and in discharge, i.e., the battery 200 is powering the device, the first FET 332 and second FET 334 of the first switching means 322 turn on (i.e., close). Therefore, when the second switching means FET 324 is off and first FET 332 and second FET 334 of the first switching means 322 are on, then data can be transmitted from the fuel gauge IC 222 via the data terminal 212 to the connected device (not shown).

[0030] When the battery 200 is connected to the charger 250, the second switching means FET 324 turns on and the first FET 332 and second FET 334 of the first switching means 322 turn off. Therefore, no data communication can occur between the fuel gauge IC 222 and the device (not shown) connected to the battery 200. Data communications, when the battery 200 is connected to the charger 250, are prevented in this manner so as to avoid data communication error (i.e., data clash) when the charger microprocessor 270 is communicating with the fuel gauge IC 222. Additionally, whenever the charger microprocessor 270 attempts to read the fuel gauge IC 222, software in the charger microprocessor 270 instructs the microprocessor 270 to turn the C/E switch FET 280 on. Turning the C/E switch FET 280 on occurs whenever the charger microprocessor 270 starts an operation to read data from fuel gauge IC 222 of the battery 200. Thereafter, the microprocessor 270 will read the data (i.e., receive the data from) in the fuel gauge IC 222. The initial state of the C/E switch FET 280 is off (i.e., open). Prior to charging the battery 200, and in order to prevent battery damage, the charger 250 must determine that the battery 200 is an authorized battery, determine what the present charge state of the battery is; and receive the battery charge parameters as well as the temperature signal of the battery cell. Therefore, the C/E switch 280 is initially off so the microprocessor 270 may receive the data prior to the charging operation.

[0031] Referring now Fig. 4, an exemplary flow chart for charging a battery using a combined positive/data charging terminal in accordance with embodiments of the invention is illustrated. A battery 200 is first connected to a battery charger 250 at step 400. The battery 200 sends the charging parameters via a two terminal interface 206 to the charger 250 at step 402. When the battery 200 initially connects to the battery charger 250, the charger 250 obtains exclusive access to the data in the fuel gauge IC 222. The charger 250 provides a voltage to the charging interface 206 of the battery 200. Therefore, the voltage at the cathode of the first Schottky diode 326 is high as is the voltage at the cathode of the second Schottky diode 328. As such, the voltage at the gate of the second switching means FET 324 is high. This results in the second switching means FET 324 turning on (i.e., the charge switching means 324 is closed). Therefore, the gates of the first FET 332 and the second FET 334 of the first switching means 322 are pulled low. As a result, the first FET 332 and the second FET 334 of the first switching means 322 are turned off (i.e., the data switching means 322 is opened). The charger 250 now has an exclusive access to the data in the fuel gauge IC 222.

[0032] The fuel gauge IC 222 sends the charging data in step 402. The charger microprocessor 270 receives the data sent from the fuel gauge IC 222 via the +/data terminal 258 through the data line 274. The microprocessor 270 adapts a charging algorithm, contained within the microprocessor 270, to the required charging procedures and parameters for the battery 200. At substantially the same time, or very shortly after receiving the charging parameters, the microprocessor 270 reads the battery temperature stored in the fuel gauge IC 222 at step 404.

[0033] Thereafter, the microprocessor 270 determines if the temperature of the battery 200 is in a range suitable for charging at step 406. Batteries can only be charged within a specific temperature range depending upon the active component used in the battery. If the battery is not within a range suitable for charging, then the microprocessor 270 suspends charging operation at step 408 and returns to step 404 to again receive temperature from the fuel gauge IC 222. If the battery 200 temperature is above a requisite predetermined temperature, the microprocessor 270 checks the battery 200 at fixed intervals until the temperature of the battery cools to within the range suitable for charging. If the battery 200 temperature is below a prerequisite or predetermined temperature, the microprocessor 270 checks the battery 200 at fixed intervals until the temperature of the battery warms to within the range suitable for charging. Once the temperature is within a range suitable for charging, the microprocessor 270 switches the C/E switch 280 from an off state (open) to an on state (close), thus enabling charger circuitry 260 to charge the battery 200 via the +/data terminal 258 and the connection to the +/data charging terminal 202 to the battery 200, and ultimately to the battery cell 320.

[0034] Then, charging operations in step 410 commence. When in the charge mode, at step 410, the voltage at the cathode of the Schottky diode 326 is high as is the voltage at the second Schottky diode 328. As a result, the voltage at the gate of the second switching means FET 324 is high, thus the second switching means FET 324 is on (charge switching means 324 is closed). Additionally, since the gates for the first FET 332 and second FET 334 are tied to the drain node of the second switching means FET 324, the gates of the first FET 332 and second FET 334 are pulled low. The pull up resistor 330 provides a voltage drop up from the cathode of first Schottky diode 326 to the gates of the first FET 332 and the second FET 334 such that their respective gates are held low and the FETS 332, 334 are off (data switching means 322 is open). Therefore, no data is transferred from the fuel gauge IC 222 through the first and second FETs 332 and 334 to the data terminal 212.

[0035] The battery 200 will continue to be charged until it is fully charged at step 412. In order to accomplish a full charging, the microprocessor 270, at fixed, predetermined intervals stops the charging operation. The charging operation is stopped temporarily so that the microprocessor 270 can perform a temperature check of the battery 200 at step 414. As a battery is charged, the battery temperature increases relative to the percent charge completed. Therefore, the microprocessor 270 reads the rise in battery temperature over time. As the battery approaches full charge, the battery temperature may increase rapidly, i.e., the rise in battery temperature over time is high. The microprocessor 270 stops the charging operation to check the battery temperature at the fixed interval depending upon the type of battery being charged. For example, the temperature monitoring, at step 414, can be performed on a varied or charging interval time, e.g., once every five (5) minutes initially, then once every thirty (30) seconds as the battery 200 approaches fully charged. The microprocessor 270 can adapt, or adjust, the charging algorithm, stored within the microprocessor 270, to vary the temperature monitoring interval occurring at step 414. The microprocessor 270 can perform, and complete, the temperature monitoring interval (step 414) within a range of about a half (0.5) millisecond to about two (2) milliseconds. After the microprocessor stops the charging operation, the microprocessor 270 obtains the battery temperature, e.g., returns the charging operation back to step 404, to determine if the battery 200 is still in the active charging range. The microprocessor 270 reads the temperature in the fuel gauge IC 222 via the data line 274, the +/data terminal 258 and the +/data charging terminal 202. If the battery temperature is not within a range suitable for charging, then the microprocessor 270 suspends charging operation to step 408 and returns to step 404 to again receive temperature from the fuel gauge IC 222. If the battery 200 is above a requisite predetermined temperature, the microprocessor 270 checks the battery 200 at fixed intervals until the temperature of the battery cools to within the range suitable for charging. If the battery 200 is below a prerequisite or predetermined temperature, the microprocessor 270 checks the battery 200 at fixed intervals until the temperature of the battery warms to within the range suitable for charging. Once the temperature is within a range suitable for charging, the microprocessor 270 switches the C/E switch 280 from an off state (open) to an on state (close), thus enabling charger circuitry 260 to charge the battery 200 via the +/data terminal 258 and the connection to the +/data charging terminal 202 to the battery 200, and ultimately to the battery cell 320. The microprocessor 270 adjusts the temperature monitoring as the microprocessor 270 determines that the battery 200 is approaching full charge. For example, as the battery 200 approaches full charge, the microprocessor 270 may reduce the amount of time between temperature monitor operations.

[0036] This charging operation continues repeatedly wherein the microprocessor 270 ceases the charging operation momentarily at fixed or predetermined intervals for temperature monitoring, as in step 414. The charging operation loop continues until such time that the microprocessor 270 determines, at step 412, that the battery is fully charged. Then, the charging operation transitions to step 416 where the microprocessor stops the charging operation. Additionally, in step 416, the microprocessor 270 may continue to provide a float charge to the battery 200. [0037] The battery 200 can now be removed from the battery charger 250 and be used to power the device. When powering the device, the battery 200 transmits power from the battery cell 320 through the positive terminal 214 and the negative terminal 210. The fuel gauge IC 222, within the battery 200, transmits a percentage charge remaining from the battery 200 via the data terminal 212 to the device. When in discharge, the battery cell 320 has a positive potential appearing at the positive terminal 214 and a negative potential at the negative terminal 210. As such, a positive potential exists at the node where the pull up resistor 330 connects to the cathode of the Schottky diode 326 and the positive terminal 214. However, there is no positive potential at the cathode of the second Schottky diode 328. Therefore, because the pull down resistor 336 is connected to the gate node of the second switching means FET 324, the potential at the gate node of the second switching means FET 324 is low (i.e., below a threshold voltage of the FET), thus the second switching means FET 324 is off (i.e., open). As a result, the voltage at the gates of the first FET 332 and the second FET 334 are pulled high to the potential of the positive terminal 214. Since the gates of the first FET 332 and the second FET 334 are high (i.e., above the threshold voltage of the FET), the FETs are on (i.e., closed), allowing the fuel gauge IC 222 to transmit data via the first FET 332 and the second FET 334 and the data terminal 212 to the device (not shown).

[0038] Referring now to Fig. 5, an exemplary battery in accordance with embodiments of the present invention is illustrated. The battery 500 has a negative charging terminal 502 and a +/data terminal 508. The battery can additionally have three terminals for interconnection with a device, which would be a negative device terminal 510, a data terminal 512 and a positive device terminal 514. Artisans of skill will appreciate that the illustration of terminals on the opposite side of the battery and the shape of the battery are exemplary and the configuration can exist in multiple ways. [0039] In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.

Claims

We claim:

1. A rechargeable battery, said rechargeable battery comprising: an external case; a first terminal on said external case; a second terminal on said external case; a charge data switching circuit, said charge data switching circuit comprising: a first switching means connected to said first terminal via a first resistor and a first diode, wherein a first junction of said first switching means is connected via said first resistor to a cathode of said first diode and an anode of said first diode is connected to said first terminal, a second switching means connected via a second diode to said first terminal, wherein a first junction of said second switching means is connected to a cathode of said second diode and an anode of said second diode is connected to said first terminal; a battery cell connected on a positive electrode to said cathode of said first diode and connected on a negative electrode to said second terminal; a fuel gauge IC; said fuel gauge IC is data connected to said first terminal and wherein said fuel gauge IC is connected between said positive electrode of said battery cell and said negative electrode of said battery cell; and wherein said charge data switching circuit is operable to switch said first terminal between an electrical charging interface and a data transfer interface.

2. The rechargeable battery of Claim 1 , wherein said first switching means comprises: a first Field Effect Transistor (FET); a second FET; wherein a gate of said first FET is connected to said first junction of said first switching means and wherein a gate of said second FET is connected to said first junction of said switching means; and wherein a drain of said first FET is connected to said first terminal and a drain of said second FET is connected to a source of said first FET.

3. The rechargeable battery of Claim 2, wherein a source of said second FET is connected to a data terminal on said external case.

4. The rechargeable battery of Claim 2, wherein said second switching means comprises a third FET, and wherein a drain of said third FET is connected to said first junction of said first switching means, a gate of said third FET is connected to said first junction of said second switching means, and a source of said third gate is connected to said negative electrode of said battery cell.

5. The rechargeable battery of Claim 4, wherein a second resistor is connected on a first side to said gate of said third FET and on a second side to said negative electrode of said battery cell.

6. The rechargeable battery of Claim 5, wherein a capacitor is connected on a first side to said gate of said third FET and on a second side to said negative electrode of said battery cell.

7. The rechargeable battery of Claim 1 , wherein the first diode and the second diode are a Schottky diode.

8. The rechargeable battery of Claim 1 , wherein the battery cell is one of lead and sulfuric acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer).

9. A battery charger, said battery charger comprising: an external case; a first interface on said external case; a second interface on said external case; charger circuitry; a charge-enable switch connected on a first terminal to said first interface and on a second terminal to said charger circuitry; and a microprocessor; said microprocessor connected on a first terminal to said charger circuitry, on a second terminal to said first interface and on a third terminal to a control terminal of said charge-enable switch, said microprocessor comprising: a computer readable medium, a plurality of instructions, wherein at least a portion of said plurality of instructions are storable in said computer readable medium, and further wherein said plurality of instructions are configured to cause said microprocessor to control said charge-enable switch to switch said first interface from a charging interface to a data transfer interface.

10. The battery charger of Claim 9, wherein said charge-enable switch is a Field Effect Transistor (FET) and wherein said control terminal is a gate node of said FET.

11. The battery charger of Claim 9, wherein said third port on said microprocessor is connected via at least one zener diode to said second interface.

12. The battery charger of Claim 9, wherein said plurality of instructions are configured to cause microprocessor to switch a positive polarity terminal, of a rechargeable battery, from an electrical charging terminal to a data transfer terminal when said positive terminal on said rechargeable battery is connected to said first interface and a negative terminal on said rechargeable battery is connected to said second interface.

13. A method for charging a battery, the method comprising: determining when a battery is connected to a battery charger; sending, from a first battery terminal on the battery, charging parameters for the battery; receiving, by the battery charger, the charging parameters for the battery; reading, by the battery charger from the first battery terminal, a battery temperature; determining if the battery temperature is within an acceptable range for charging the battery; starting a charging operation comprising charging the battery via the first and a second terminal if the battery temperature is within the acceptable range, and determining if the battery is fully charged; stopping the charging operation if the battery is fully charged.

14. The battery charging method of Claim 13, further comprising: delaying the charging operation for a specified period of time if the battery temperature is not within the acceptable range, re-reading, by the charger from the first battery terminal, the battery temperature; and re-determining if the battery temperature is within an acceptable range.

15. The battery charging method of Claim 14, further comprising, suspending the charging operation after the charging operation has been started.

16. The battery charging method of Claim 13, further comprising: suspending the charging operation, if the battery is not fully charged, at a predetermined interval of time to ascertain the battery temperature; re-reading, by the charger from the first battery terminal, the battery temperature; and re-determining if the battery temperature is within an acceptable range.

17. The battery charging method of Claim 16, further comprising: adjusting the predetermined interval time.

18. The battery charging method of Claim 13 , wherein stopping the charging operation comprises providing a floating charge to the battery.

19. The battery charging method of Claim 13, further comprising switching, by the charger, at least one terminal on the charger from an electrical charger terminal to a data transfer terminal.

20. The battery charging method of Claim 13, further comprising switching, by the charger, the first battery terminal on the battery from an electrical charger terminal to a data transfer terminal.