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WO2001028064A2 - Systeme de gestion de batterie - Google Patents

Systeme de gestion de batterie Download PDF

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Publication number
WO2001028064A2
WO2001028064A2 PCT/US2000/028429 US0028429W WO0128064A2 WO 2001028064 A2 WO2001028064 A2 WO 2001028064A2 US 0028429 W US0028429 W US 0028429W WO 0128064 A2 WO0128064 A2 WO 0128064A2
Authority
WO
WIPO (PCT)
Prior art keywords
cunent
rechargeable battery
charge
minor
battery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2000/028429
Other languages
English (en)
Other versions
WO2001028064A3 (fr
Inventor
Joseph Drori
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xicor LLC
Original Assignee
Xicor LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/417,521 external-priority patent/US6154012A/en
Priority claimed from US09/620,089 external-priority patent/US6501249B1/en
Priority claimed from US09/620,090 external-priority patent/US6522104B1/en
Application filed by Xicor LLC filed Critical Xicor LLC
Priority to AU10851/01A priority Critical patent/AU1085101A/en
Publication of WO2001028064A2 publication Critical patent/WO2001028064A2/fr
Publication of WO2001028064A3 publication Critical patent/WO2001028064A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3828—Arrangements for monitoring battery or accumulator variables, e.g. SoC using current integration
    • G01R31/3832—Arrangements for monitoring battery or accumulator variables, e.g. SoC using current integration without measurement of battery voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00302—Overcharge protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00304—Overcurrent protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00308—Overvoltage protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
    • H02J7/00716—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current in response to integrated charge or discharge current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from AC mains by converters
    • H02J7/04—Regulation of charging current or voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]

Definitions

  • the present invention relates generally to electronic devices and more particularly to a method and apparatus for monitoring the charging and discharging of a battery.
  • Rechargeable batteries are used in many applications to power a variety of devices. Different devices will discharge rechargeable batteries at different rates depending on the function being performed by the device and co ⁇ esponding load being applied across the battery terminals. For example, a portable computer may discharge a rechargeable battery quickly when computing complex graphic calculations on a processor and rendering a graphic image on a display. The same portable computer may discharge the rechargeable battery more slowly when it is placed in "stand-by mode" and operation of the computer is temporarily suspended. Even when the portable computer is turned off, the rechargeable battery may also continue to discharge a small amount of cu ⁇ ent over time due to the internal resistance present in the battery.
  • the rechargeable battery is charged with a transformer that converts cu ⁇ ent from a conventional electrical outlet or automobile lighter into direct cu ⁇ ent suitable for charging the battery. Once the rechargeable battery reaches a maximum voltage, it is fully charged. To protect both the rechargeable battery and the electronic device that it powers, it is important to carefully monitor and control the charging and discharging processes. Specifically, a battery can overheat and be damaged during the charge cycle if it is charged beyond the specified battery capacity. Overcharging can also harm the electronic device as well as people handling the device if the battery leaks or is damaged. In the discharge cycle, for example, an electronic device may be damaged if a short develops within the battery or the device and the sudden increase in current causes the battery or device to overheat or melt.
  • the device used to measure the charge/discharge state of a battery is popularly called a "gas gauge.” Like the gas gauge on an automobile, the battery gas gauge measures how much charge is stored in a battery.
  • Conventional gas gauge devices measure the cu ⁇ ent flow into and out of the rechargeable battery to measure the battery's charge. These conventional gas gauges detect the cu ⁇ ent flow using a fixed resistor coupled in series between the battery and the load. The voltage drop across the series resistor is directly proportional to the current flow measurements into or out of the rechargeable battery. Unfortunately, this series resistor, though typically very small in size, consumes a significant portion of the available power delivered by the rechargeable battery over time.
  • a small series resistor cannot be used to accurately detect the wide range of cu ⁇ ents drawn by many of the electronic devices. That is, the voltage drop produced by the very small series resistor may only be accurately detected when the cu ⁇ ent flow is high. If the cu ⁇ ent flow is low, most conventional gas gauges may inaccurately measure the very small voltage drop across this very small resistor. For example, the conventional gas gauge may not accurately detect the lower cu ⁇ ent used when a computer is placed in "stand-by" mode.
  • the series resistor size can be increased to increase measurement accuracy, the larger series resistor will also increase the power lost across the series resistor and, at high cu ⁇ ents, further reduce the voltage available to drive the load.
  • a battery management system for a rechargeable battery includes a charger unit that charges the rechargeable battery, a load capable of receiving cu ⁇ ent from the rechargeable battery, an integrated power and sense device including a power device and a sense device, the integrated power and sense device coupled between the rechargeable battery, the load, and the charger unit wherein the sense device provides a first mirror cu ⁇ ent proportional to the charge current flowing into the battery from the charger unit and a second minor cu ⁇ ent proportional to the discharge cu ⁇ ent from the rechargeable battery, the power device is configured to disconnect the rechargeable battery from the charger and the load upon receipt of a disconnect signal; a battery management unit capable of generating a disconnect signal operatively coupled to the first minor cunent and the second minor cunent that uses the first and second minor cu ⁇ ents to measure the charge flowing into and out of the rechargeable battery wherein a total charge of the rechargeable battery is determined using the measured charges flowing into and out of the rechargeable battery.
  • Another aspect of the invention includes a battery management system for a rechargeable battery, including a load, an integrated power and sense device including a power device and a sense device, the integrated power and sense device connected between the rechargeable battery and the load wherein the sense device provides a minor cunent proportional to the cunent in the power device, a first circuit that measures the rechargeable battery cunent using the minor cunent, and a second circuit that measures the charge in the rechargeable battery using the minor cunent.
  • Yet another aspect of the invention includes a method of measuring electrical conditions in the battery, including providing a minor cunent, integrating the minor cunent to measure charge in the rechargeable battery, comparing the minor cunent with a cunent threshold value, and detecting an overcunent condition based on the comparison.
  • a method of disconnecting a rechargeable battery includes the steps of providing a minor cunent, measuring charge in the rechargeable battery using a bi-directional power and sense device and the minor cunent, and disconnecting the rechargeable battery using the bi-directional integrated power and sense device.
  • FIG. 1 is a block diagram of a rechargeable battery powered system using a battery management system to control charge and discharge of a battery consistent with the present invention.
  • FIG. 2 is a block diagram illustrating the components used in the Battery Management Unit (BMU) portion of FIG. 1 to manage charging and discharging of a battery.
  • BMU Battery Management Unit
  • FIG.3 is a diagram illustrating a gas gauge circuit used to measure the charge into and out of a battery during charge and discharge cycles.
  • FIG. 4 is a block diagram of the interface control unit (ICU) portion of the BMU of FIG. 2.
  • ICU interface control unit
  • FIG. 5 is a pulse diagram that indicates the start, acknowledge, zero, and one conditions used by a serial protocol in the battery charger system.
  • FIG. 6 is a circuit diagram illustrating a bi-directional sense FET used to generate minor cu ⁇ ents for measuring the battery charge.
  • FIG. 1 provides a block diagram of a battery management system 100.
  • Battery management system 100 includes a rechargeable battery, hereinafter battery 102, a battery management unit (BMU) 104, a load 106, a charger unit 108 for charging battery 102, and a switch and sense device (SSD) 110.
  • BMU 104 and SSD 110 are integrated together in a single chip using customized analog, non-volatile memory, and logic circuits. Consistent with the present invention, BMU 104 and SSD 110 can be implemented by distributing logic functions to different components or using a programmable controller or central processor and bus. In general, integrating the components in battery management system 100 together makes using the system more efficient and cost-effective in a wider variety of electronic applications.
  • Battery 102 is a rechargeable battery typically used in electronic devices such as computers, cameras, personal digital assistants (PDA), or power tools.
  • Battery 102 can be designed using a variety of materials including Nickel Cadmium (NiCd), Nickel Hydride (NiH), and Lithium Ion (Li).
  • a positive terminal and negative terminal on battery 102 is operatively coupled to the co ⁇ esponding terminals of load 106 and provides cunent to operate load 106.
  • battery 102, BMU 104, SSD 110, and charger unit 108 can be designed and assembled as an integrated "smart battery" for use in electronic devices.
  • BMU 104 and SSD 110 can be developed separately as discrete components and then programmed through the serial port, discussed in further detail below, to operate with existing batteries.
  • BMU 104 monitors safety conditions within battery management system 100 including over voltage, under voltage, over cunent, and operating temperature and communicates this information to a host over serial interface 111.
  • BMU 104 is operatively coupled to battery 102, SSD 110, load 106, and charger unit 108.
  • BMU 104 includes a battery safety unit (BSU) 202, a charge monitor, hereinafter refened to as a gas gauge 204, an interface and control unit (ICU) 206, a bus 214 and memory 208 having data 210 and battery status 212.
  • BSU battery safety unit
  • ICU interface and control unit
  • BSU 202 can include an integrated temperature sensor and logic for processing temperature information associated with battery 102 and other components.
  • a pn-diode attached to BMU 104 is used to measure temperature fluctuations in the system.
  • the pn-diode can be used as a temperature sensor by measuring the voltage variation that occurs in the pn-diode as the temperature fluctuates.
  • an external temperature sensor such as a thermocouple, thermistor or diode can be used to detect the temperature of battery 102 in FIG. 1.
  • BSU 202 may also rely on an arithmetic unit 408 (see FIG. 4) in ICU 206 to perform calculations. Further, BSU 202 may store temperature, voltage, and cunent threshold values in local registers or over bus 214 and into memory 208. Preferably, bus 214 acts as a transport mechanism for transfening data between components within BMU 104. For example, BSU 202 may use bus 214 to access memory 208, communicate with ICU 206, and transmit a special "Temp P" signal over serial interface 111 when the measured temperature exceeds a predetermined value or goes below a predetermined value. This "Temp P" signal allows external devices to receive the device temperature end value.
  • BSU 202 monitors the rate at which battery 102 charges and discharges.
  • OCP over charge protection
  • a simple timing circuit determines if the rate of charging or discharging exceeds a predetermined threshold and may cause damage to battery 102, load 106 or other components.
  • BSU 202 compares voltage, cunent and temperature conditions with predetermined levels and operates to turn off the cunent flowing into or out of battery 102 using SSD 110 if a threshold is exceeded.
  • BSU 202 also can issue a warning to the host by changing status bits in battery status 212.
  • BSU 202 can also transmit a predetermined safety signal to ICU 206 that a host device external to BMU 104 can detect.
  • BSU 202 may instruct ICU 206 to transmit a signal on serial interface 111 associated with ICU 206 indicating the specific safety or alarm condition.
  • the safety or alarm condition can be transmitted to the host by holding a single wire serial interface associated with ICU 206 low for a period of 1 msec, indicating to the host that a safety condition has occuned and needs attention. The single wire interface is discussed in further detail below.
  • the predetermined threshold values associated with over voltage, under voltage, over cu ⁇ ent, and operating temperatures can be programmed in BMU 104 to accommodate the specific operating characteristics of battery 102. These levels can be initially programmed into BMU 104 during assembly and before shipment to the customer.
  • GAS GAUGE Gas gauge 204 uses SI, S2, CS1 and CS2 inputs to accurately sense the cunent flow in SSD 110. Inputs CS1 and CS2 provide a sense cunent proportional to the cunent passing through battery 102. Proportional cunents, such as the proportional sense cunent, are also refened to as ratioed cunents. By measuring the charge passing through inputs CS1 and CS2, gas gauge 204 can determine the total charge in battery 102. The remaining capacity of the battery is then determined by comparing the expected capacity of the battery with the measured charge. Gas gauge 204 can also keep track of the total charge into battery 102 and total discharge from battery 102.
  • the charge information can be used to determine if the total capacity of a battery is being diminished over time and the battery needs replacing. For example, a battery is not holding a charge well when the difference between the total discharge and total charge of a battery exceeds a predefined threshold.
  • gas gauge 204 updates a predetermined storage location in memory 208 to hold the total charge and total discharge charge information. Refening now to FIG. 1 and FIG. 3, an exemplary circuit used in gas gauge 204 is shown that measures a minor cunent passing through input CSl as battery 102 charges. A similar circuit attached to input CS2 can be used to measure the discharge from battery 102. To better illustrate how gas gauge 204 operates, a portion of the circuitry from SSD 110 is also included in FIG. 3.
  • Gas gauge 204 includes a cunent integrator section 301 and a charge counter section 311.
  • Cunent integrator section 301 includes a comparator 302, a voltage source 304, a transistor 306, a transistor 308, and a capacitor 310.
  • Charge counter section 311 includes a comparator 312, a transistor 322, an inverter 316, and a counter 318.
  • the negative terminal of comparator 302 is coupled to receive input SI and the positive terminal of comparator 302 is coupled to receive input CSl.
  • Input SI is coupled to the source of power transistor 602.
  • the cunent used to charge battery 102 passes through power transistor 602.
  • Input CSl is coupled to the source of the sense transistor 606 and canies a minor cunent proportional to the cunent used to charge battery 102.
  • input CSl is also coupled through transistor 306 to voltage source 304 labeled VB1.
  • Output VB2 from comparator 302 is coupled to the gates of transistor 306 and transistor 308.
  • Voltage source 304 is coupled to the sources of transistor 306 and 308; thus transistor 308 is a cunent minor of transistor 306.
  • the drain of transistor 308 is coupled to the drain of transistor 322, the positive terminal of capacitor 310, and the negative terminal of comparator 312 used by charge counter 311.
  • the source of transistor 322 is coupled to ground and the drain of transistor 322 is coupled to the positive terminal of capacitor 310.
  • the negative terminal of capacitor 310 is coupled to ground and the positive terminal of capacitor 310 receives minor cunent from transistor 308.
  • comparator 312 is coupled to receive input VB3 at its positive terminal and provide its output to the input of inverter 316.
  • An output from inverter 316 is coupled to an input on counter 318 and the gate of transistor 322 such that it increments the counter and switches transistor 322.
  • cunent integrator section 301 detects the charge and charge counter section 311 measures the total charge.
  • the cunent used to charge battery 102 flows through power transistor 602.
  • Comparator 302 compares the voltage on input SI with the voltage at input CSl. If the voltage differs, comparator 302 generates a voltage VB2 such that transistor 306 turns on and delivers more cu ⁇ ent to input CSl .
  • the voltage generated by comparator 302 at output VB2 forces the voltage on input CSl to equal the voltage at input SI.
  • cunent through input CSl is an accurate ratio of the cunent through power transistor 602 (the battery cunent).
  • the exact proportions of the cunents are determined by the relative sizes of the power and sensing transistors 602 and 606, respectively.
  • the transistors can be sized such that the minor cunent is ratioed differently for different amounts of cunent. For example, if the cunent is very small the ratio of the transistor sizes may be reduced such that the sense cunent is more sensitive to small cunents.
  • the transistors are field effect transistors (FETs) or MOSFETs sized so that the minor cunent is approximately 1/1000th of the cunent passing through power transistor 602 and battery 102.
  • the transistors could be sized such that the minor cunent is as large as 1/100 of the cunent passing through the power transistors.
  • the voltage VB2 from comparator 302 also turns on transistor 308, producing a proportional minor cunent that can be used to charge capacitor 310.
  • the charging of capacitor 310 integrates the minor cunent from transistor 308. Consequently, capacitor 310 measures charge without using a time base.
  • comparator 312 When the charge on capacitor 310 matches the voltage on input VB3, a unit of charge has been measured and comparator 312 generates a pulse on its output.
  • This pulse causes inverter 316 to increment counter 318 indicating an additional unit of charge has been added to battery 102 by charger unit 108.
  • the pulse on the output of comparator 312 turns on transistor 322 and discharges capacitor 310. This prepares capacitor 310 to receive another unit of charge before the charge measurement process described above repeats. If the dimensions of transistor 306 and transistor 308 are equal, the cu ⁇ ent through transistor 308 minors the cunent through transistor 306 and is proportional to the cunent in power transistor 602.
  • transistor 308 can be sized to receive less cunent from cunent source 304. This alternate implementation would also use a proportionally smaller capacitor 310 and would consume less power in measuring the battery charge.
  • the value in counter 318 represents a charge proportional to the charge the battery has received during a charge cycle. Accordingly, one can calculate how much the battery has been charged and whether the battery is at full capacity. Because capacitor 310 continuously integrates the cunent, gas gauge 204 can measure the battery charge without a time measurement or time period for sampling. Further, gas gauge 204 can accurately measure minor cunents ranging from the picoAmp range to the milliAmp range.
  • separate counters can be used to measure the amount a battery has been charged or discharged.
  • the two counters can keep track of the total charge entering and leaving the battery. To determine the net charge of the batter, the value in one counter is subtracted from the value in the second counter. The two counters can also be used to determine information such as the number of battery cycles for charging.
  • ICU INTERFACE AND CONTROL UNIT
  • ICU 206 manages and safety condition threshold values, processes requested from external host devices, arithmetic operations and results, and communications with host devices over serial interface 111.
  • ICU 206 includes serial interface logic 402, interrupt logic 404, alarm logic 406, and arithmetic unit 408.
  • Serial interface logic 402 includes logic for using a serial protocol over a serial interface 111, between a master and a slave device as well as processing commands transmitted over the serial interface. For example, serial interface logic 402 detects commands, and transmits appropriate signals to operate components within BMU 104.
  • the serial protocol embedded in serial interface logic 402 defines a transmitter as a device that sends data on the serial interface 111 and a receiver as a device that receives the data. Further, the device controlling the transfer is a master and the device being controlled is the slave. The master device always initiates data transfers and provides the starting commands for both the transmit and receive operations.
  • BMU 104 operates as a slave unit to an external master device and the serial interface 111 on BMU 104 is set to receive mode on power up.
  • the master issues a start signal followed by a command byte and the address associated with a byte of data to be accessed in memory 208.
  • the receiving slave unit responds by sending an acknowledge signal between each command.
  • the master also responds to the slave with an acknowledge signal each time the master receives 8 bits of data.
  • BMU 104 uses serial interface 111 associated with serial logic 402 to carry data between an external master device and memory 208.
  • Serial interface 111 operates in a half duplex mode and memory 208 can include a variety of storage devices such as a 4K E 2 PROM, a 512 bit E 2 PROM look up table (LUT), a 256 bit, non- volatile random access memory (NovRAM) or a 128 bit one-time-programmable (OTP) unit.
  • a pulse diagram indicates a start, acknowledge (ACK), one, and zero signals used by the serial protocol.
  • the serial protocol provides BMU 104 a mechanism for communicating information related to the operation of BMU 104.
  • BMU 104 uses this protocol over a single conductor connected between BMU 104 and a device external to BMU 104.
  • the protocol uses a sequence of pulses on the single conductor where the number of pulses conesponds to the signals being transmitted.
  • Start signal 504 in FIG. 5 indicates the start of information transmission over the single conductor connected to BMU 104.
  • the start command generally precedes a command.
  • the start command consists of five pulses each having a low duration of 30 microseconds. Each pulse is separated by a high duration lasting 30 microseconds. The last high duration lasts at least 90 microseconds indicating transmission for the start signal is complete.
  • BMU 104 monitors serial interface 111 for this start signal and will not respond to any command or data until this condition is detected.
  • Start signal 504 can also be used to terminate the input of a control byte or the input data to be written. This will reset the device and leave it ready to begin a new read or write command. It is worth noting that start signal 504 cannot be generated while BMU 104 is outputting data.
  • Ack signal 506 is a signal used to indicate successful transfer of information using the communication protocol. For example, a device transmitting information to BMU 104 releases the single conductor connected to BMU 104 after transmitting a series of eight data bits and during the ninth bit period, BMU 104 sends an ack (short for
  • ack signal 506 is a sequence of four pulses each having a low duration of 30 microseconds. Each pulse is separated by a time interval having a high duration of 30 microseconds. Like start signal 504, ack signal 506 is complete when a high duration time interval lasting at least 90 microseconds is transmitted. BMU 104 responds with ack signal 506 after receiving start signal 504 and after transmitting each byte to the master.
  • One signal 508 indicates transmission of a data value of one. In one implementation, three pulses are transmitted for one signal 508 as indicated in FIG. 5. Each pulse has a low duration of 30 microseconds separated by a high duration of 30 microseconds.
  • Zero signal 510 indicates transmission of a data value of zero. Two pulses are transmitted for zero signal 510 as indicated in FIG. 5. Like other signals described above each pulse used in one signal 508 and zero signal 510 has a low duration of 30 microseconds and is separated by a time interval with a high duration 30 microseconds. The last high duration time interval lasts at least 90 milliseconds and indicates that the signal has completed transmission.
  • serial interface logic 402 When serial interface 111 remains idle for a time interval longer than 1 millisecond., serial interface logic 402 resets serial interface 111. With the exception of interrupting a write to memory, serial interface logic 402 resets serial interface 111 regardless of transmission state being sent or the signal level being transmitted (i.e., high or low). For example, a reset may occur if an idle period greater than 1 millisecond occurs in the middle of a data communication session with a host. Specifically, ICU 206 when not being driven by either a master or slave device sets serial interface 111 to a high value. Accordingly, the master device must reissue a start signal to resume communication once a reset occurs.
  • the master device can issue a variety of commands once a start signal is successfully received by serial interface logic 402.
  • eight bit commands are transmitted over serial interface 111 using a sequence of pulses as described above.
  • Each command byte contains bits CO through C7 and operates to perform the following list of operations or functions:
  • interrupt logic 404 processes external command requests occuning while BMU 104 is performing one or more internal functions. For example, interrupt logic 404 determines how to process an external command given to BMU 104 while the gas gauge is updating the battery charge level or arithmetic unit 408 is performing a calculation. Interrupt logic 404 supports concunent interrupts and may also generate an interrupt compatible with a personal computer (i.e., IRQn). This IRQ interrupt signal can also be transmitted separately over a second communication line (not shown).
  • IRQn an interrupt compatible with a personal computer
  • interrupt logic 404 allows BMU 104 to complete the internal operations without interruption and sets a status bit in a status register stored in memory 208 indicating that a conflict with an internal operation has occuned. Interrupt logic 404 does not send an acknowledge signal to the master device making the request. Instead, it is up to the master device to read the status register, determine if a conflict has occuned, and reissue the command. In practice, the master device may need to reissue the external command several times before the internal operations within BMU 104 are completed and the external command can be performed. If the master device does not read the status register, the status bit remains set until a subsequent read status register command issues.
  • Alarm logic 406 is operable to process safety and alarm conditions that occur in BSU 202.
  • alarm logic 406 includes 8 user programmable alarms and 2 safety conditions for detecting over voltage and under voltage conditions.
  • the user can program the alarms to monitor a variety of conditions.
  • alarms can be programmed to monitor battery voltage and over cunent conditions as charging or discharging occurs or alternatively may be programmed to monitor specific temperature levels of the battery or circuitry within battery management system 100.
  • An over voltage safety condition is programmed to detect a maximum voltage level in battery 102 while the under voltage safety condition can be programmed to detect an under voltage condition.
  • ICU 206 stores status information in the status register.
  • the status register is at a fixed location in data 210 or battery status 212.
  • a "Write Enable” command must be issued over serial interface 111.
  • a "Disable Write” command must be issued over serial interface 111 in a similar manner to prevent any future accidental write.
  • BSU 202, gas gauge 204, and ICU 206 are integrated together as a single unit such as BMU 104. By placing BMU 104 in test mode, input OCP, input PTC, input CS 1 , input CS2, input Vcc, and serial interface 111 can be used to select and program alarms and other threshold values.
  • BSU 202 When BMU 104 is not in test mode, BSU 202 operates normally and these inputs and outputs operate as described above. In one implementation, raising serial interface 111 on ICU 206 to a high voltage such as 12V for a period of 10 millisecond sets BSU 202 in test mode.
  • the over voltage safety level can be reset by setting the input PTC high and holding input OCP, input CSl and input CS2 pins low.
  • the voltage protection level can be set by setting the voltage on the Vcc pin to the desired over voltage protection level.
  • the input PTC and input CS2 are held high while the input OCP and input CSl pins are held low.
  • Raising the serial port on ICU 206 to a high voltage such as 12V for 10-millisecond programs the over voltage protection level to the voltage level set on Vcc. Similar operations can be used to set the under voltage and over cunent safety levels in BMS 100.
  • Temperature safety levels are set in BMS 100 by writing a maximum and minimum temperature safety level in a predetermined memory location within data 210 of memory 208. Specifically, the digital value of the desired temperature safety levels can be transmitted through serial interface 111, described above.
  • Arithmetic unit 408 in FIG. 2 performs calculations within BMU 104. For example, arithmetic unit 408 performs calculations such as adding a predetermined battery capacity to the gas gauge during charge time or subtracting the same capacity from gas gauge during discharge time. Further, arithmetic unit 408 can be used to extrapolate data between two discrete values. If battery capacity data in BMU 104 only exists for two temperature values such as 25° C and 100° C and the measured temperature is 70° C, arithmetic unit 408 can extrapolate the battery capacity data for 70° C, based on the available capacity values associated with the two known temperature values. This allows BMU 104 to provide a more accurate prediction of the remaining battery capacity given a wider range of temperatures.
  • MEMORY MEMORY
  • memory 208 stores threshold information and other data for use by BMU 104 and includes data 210 and battery status 212.
  • data 210 includes a status register and a look-up-table.
  • the status register stores safety conditions such as over voltage, over cunent, under voltage, minimum temperature, maximum temperature, special conditions such as battery capacity full and conflict information (i.e., interrupt flag), 8 alarm conditions, and at least one status flag reserved for customization.
  • the look-up-table (LUT) includes information such as a list of discrete operating temperatures in 5-15 degree increments from 100° C down to -20° C and specific parameters related to operation of battery 102 (FIG.
  • rated charge count per lmilliamp-hr such as rated charge count per lmilliamp-hr, rated capacity, count period value, temp conection count period, battery self discharge value, temperature (temp) conection self discharge, temp point capacity reduction, temp rate capacity reduction, hi cunent point capacity (cap) reduction, hi cunent rate cap reduction, cycle A and cycle B count multiplier, total charge/discharge multipliers, alarms setup, maximum temp safety level, minimum temp safety level, and watch dog time and over cunent (OC) control.
  • the charge/discharge multipliers help determine the ability to recharge a battery.
  • Battery status 212 can include a separate status register, a "gas" gauge for the battery, cycle A and cycle B registers, total charge registers, total discharge registers, and user defined registers.
  • SSD 110 detects the cunent passing through battery 102 to protect the battery and circuitry as well as measure the charge in battery 102. If BMU 104 detects a cunent condition outside predetermined limits, BMU 104 sends a signal to SSD 110 over power transistor control (PTC) input to shut off the cunent to battery 102.
  • PTC power transistor control
  • SSD 110 also facilitates measuring the charge in battery 102. Specifically, SSD 110 generates minor cunents on inputs CSl and CS2 directly proportional to the cunent flow charging or discharging battery 102. These minor cunents are used by gas gauge 204 in BMU 104 to measure the charge into and out of battery 102 and indicate the charge level in the battery.
  • FIG. 6 illustrates a bi-directional sense FET 600 included in SSD 110 to facilitate generating the minor cunents through inputs CSl and CS2.
  • Bi-directional sense FET 600 includes a power transistor (FET) 602, a power FET 604, a sense transistor (FET) 606, a sense FET 608, a diode 610, a diode 612, a diode 614, and a diode 616.
  • the source of power FET 602 is coupled to the input of diode 610 and the source power FET 604 is coupled to the input of diode 612.
  • the output of diode 610 and diode 612 are coupled to the drains of power FET 602 and power FET 604 as well as the drain of sense FET 606 and the drain of sense FET 608.
  • the source of sense FET 606 is coupled to the input of diode 614 and to input CSl.
  • the source of sense FET 608 is coupled to the input of diode 616 and to input CS2. Outputs from diode 614 and diode 616 are coupled together.
  • bi-directional sense FET 600 uses sense FET 606 and sense FET 608 to measure the charge cunent flowing through power FET 602 or the discharge cunent flowing in the opposite direction through power FET 604.
  • BMU 104 When BMU 104 is operating normally, BSU 202 provides a voltage to the gate of each FET 602, 604, 606 and 608 such that the FETs are biased on and the charge or discharge cunent flows through SSD 110.
  • BSU 202 (FIG. 2) shuts off each FET to prevent further charging or discharging of battery 102.
  • the cunent flows from the source (S2) to the drain (D) of power FET 604 through the drain (D) and source (SI) of power FET 602 and to the negative terminal of battery 102.
  • Gas gauge 204 supplies cunent to input CS2 such that the voltage at input CS2 equals the voltage at input S2.
  • the cunent through input CS2 is an accurate ratio of the cunent flowing through SSD 110 to battery 102.
  • the minor cunent through input CS2 is used to measure the charge from the battery during a discharge cycle.
  • the cunent flows from the source (SI) to the drain (D) of power FET 602 through the drain (D) and source (S2) of power FET 604 and to the negative terminal of the charger unit 122.
  • gas gauge 204 supplies cunent to input CSl such that the voltage at input CSl equals the voltage at input SI .
  • the cunent through input CSl is an accurate ratio of the cunent flowing through SSD 110 to battery 102.
  • the minor cu ⁇ ent passing through input CSl is used to measure the charge to the battery during a charge cycle.
  • BMU 104 operates during charge and discharge cycles.
  • charger unit 108 provides cunent flow through the positive terminal of battery 102, through the battery and SSD 110, returning to the negative terminal of charger unit 108.
  • SSD 110 develops a minor cunent through input CSl, which tracks the charging of battery 102. If the charge cunent measured by BMU 104 remains within a prescribed operating range, BMU 104 continues to bias transistors in SSD 110 such that battery 102 receives cunent from charger unit 108.
  • charger unit 108 converts alternating cunent from an electrical socket into appropriate direct cunent suitable for charging battery 102.
  • charger unit 108 can also be integrated into BMU 104 as an additional component for use when power for charger unit 108 is available. If charger unit 108 is on and load 106, such as a computer system, is in use, then charger unit 108 will support load 106 and partially charge battery 102.
  • battery 102 In discharge mode, battery 102 provides a cunent to load 106.
  • Charger unit 108 is typically not present when battery 102 discharges.
  • cunent flows from the positive terminal of battery 102, through the conesponding positive terminal of load 106, through load 106, and from the negative terminal of load 106 into SSD 110.
  • SSD 110 develops minor cunent through input CS2 that tracks the discharging of battery 102.
  • BMU 104 will detect an over voltage condition in battery 102. Specifically, BMU 104 compares the voltage value provided over the Vcc input with a predetermined threshold voltage value associated with the battery. If the voltage value on the Vcc input exceeds this threshold value, BMU 104 signals to SSD 110 over the PTC output to cutoff cunent flow to battery 102. This will also cause SSD 110 to switch off the minor cu ⁇ ent flow through input CSl.
  • n-channel devices in the SSD connected to the negative battery terminal have been described, alternative implementations can use p-channel devices in the SSD. Either n-channel or p-channel devices can be connected to either the positive or negative battery terminal depending on the configuration.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

L'invention concerne un système de gestion de batterie, qui comporte une unité de gestion de batterie (BMU) et un dispositif intégré de détection et de commutation (SSD) servant à mesurer précisément l'état de charge d'une batterie rechargeable et à assurer une protection de charge de la batterie rechargeable. Le système comporte une charge, un dispositif intégré de détection et d'alimentation comprenant un dispositif d'alimentation et un dispositif de détection ; le dispositif intégré de détection et d'alimentation est connecté entre la batterie rechargeable et la charge ; le dispositif de détection fournit un courant miroir proportionnel au courant du dispositif d'alimentation ; un premier circuit mesure le courant de la batterie rechargeable à l'aide du courant miroir, et un deuxième circuit mesure la charge de la batterie rechargeable à l'aide du courant miroir.
PCT/US2000/028429 1999-10-13 2000-10-12 Systeme de gestion de batterie Ceased WO2001028064A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU10851/01A AU1085101A (en) 1999-10-13 2000-10-12 Battery management system

Applications Claiming Priority (9)

Application Number Priority Date Filing Date Title
US15922799P 1999-10-13 1999-10-13
US09/417,521 US6154012A (en) 1999-10-13 1999-10-13 Gas gauge implementation
US60/159,227 1999-10-13
US09/417,521 1999-10-13
US09/620,090 2000-07-20
US09/620,308 2000-07-20
US09/620,089 US6501249B1 (en) 1999-10-13 2000-07-20 Battery management system
US09/620,090 US6522104B1 (en) 1999-10-13 2000-07-20 Method and apparatus for measurement of charge in a battery
US09/620,089 2000-07-20

Publications (2)

Publication Number Publication Date
WO2001028064A2 true WO2001028064A2 (fr) 2001-04-19
WO2001028064A3 WO2001028064A3 (fr) 2001-08-30

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WO (1) WO2001028064A2 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7151378B2 (en) 2001-09-25 2006-12-19 Wilson Greatbatch Technologies, Inc. Implantable energy management system and method
CN103975499A (zh) * 2011-09-27 2014-08-06 尼尔菲斯克－阿德万斯有限公司 电池控制系统
EP3106891A1 (fr) * 2015-06-15 2016-12-21 Quanta Computer Inc. Dispositifs et procédés de diagnostic de batterie
CN107359677A (zh) * 2017-09-05 2017-11-17 纽福克斯光电科技（上海）有限公司 检测装置、系统以及汽车

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3298600B2 (ja) * 1994-07-26 2002-07-02 ミツミ電機株式会社 二次電池保護装置
US5648715A (en) * 1995-11-24 1997-07-15 Motorola, Inc. Method and apparatus for current compensation of a battery in a charger
JP3731951B2 (ja) * 1996-09-24 2006-01-05 ローム株式会社 リチウムイオン電池保護回路

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7151378B2 (en) 2001-09-25 2006-12-19 Wilson Greatbatch Technologies, Inc. Implantable energy management system and method
CN103975499A (zh) * 2011-09-27 2014-08-06 尼尔菲斯克－阿德万斯有限公司 电池控制系统
CN103975499B (zh) * 2011-09-27 2017-03-29 力奇有限公司 电池控制系统
EP3106891A1 (fr) * 2015-06-15 2016-12-21 Quanta Computer Inc. Dispositifs et procédés de diagnostic de batterie
CN107359677A (zh) * 2017-09-05 2017-11-17 纽福克斯光电科技（上海）有限公司 检测装置、系统以及汽车
CN107359677B (zh) * 2017-09-05 2024-04-12 纽福克斯光电科技（上海）有限公司 检测装置、系统以及汽车

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Publication number Publication date
WO2001028064A3 (fr) 2001-08-30
AU1085101A (en) 2001-04-23

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