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
  • H02J7/02—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
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/44—Methods for charging or discharging
• • 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
  • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
• • 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
  • H02J7/0071—Regulation of charging or discharging current or voltage with a programmable schedule
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates generally to battery charging methods and system and more particularly to charging methods and systems for preventing battery overcharge.
• Rechargeable batteries for storing electrical energy, and battery chargers, for charging
• a common charging method is to apply a voltage source to the battery to be charged, which is greater than the battery
• a battery charging method that minimizes overcharging, and, thus, increases battery performance and life is needed.
• the battery charging method should be capable of
• batteries i.e., whether the batteries are substantially charged or substantially fully depleted early during the charging cycle, and charge the batteries accordingly, based
• Batteries generally consist of two or more galvanic cells. Two electrodes of dissimilar materials are isolated one form the other electronically, but placed in a common
• Silver-based batteries typically have high energy densities, i.e., high energy to weight
• volume ratios an ability to deliver energy at relatively high current drains, and high
• the first plateau occurs as silver is transformed to monovalent silver oxide (Ag 2 O) while the second plateau reflects the formation of
• charging method and system should taper charge the battery, so as not to drive too much
• Such batteries may be used in spacecraft and in other applications, requiring
• the charging method and system should be inexpensive, easy to
• connected battery cells which include a plurality of shunt regulators, adapted to be connected in parallel with each of the cells.
• the voltage of each cell is
• Turnbull shows different embodiments of his shunt regulators.
• Turnbull simply shows shunt regulators, each in parallel with a battery cell.
• Turnbull uses shunt
• Each shunt regulator is
• Turnbull uses a plurality of isolation switches to disconnect the
• the shunt circuit includes shunt regulators connected
• a sensor for detecting an operating condition of a battery cell such as
• controller connected across the battery cell of a lithium ion battery, the controller then being operable to change to the
• controller includes a voltage limiting operational amplifier operable for
• the method comprises analyzing the profile for the
• inflection points which identify the point in time at which the application of a
• the variation of the characteristic with time is analyzed, preferably by measuring successive values of the
• Apparatus for performing these methods comprises a power supply and a microcomputer for analyzing the profile and controlling the power
• Saar and Brotto show a voltage-time curve, which can be separated into at least
• Region I represents the beginning of the charging
• Region II is generally the
• region II At the end of region II is an
• Region III is the region in which the
• the charging voltage only stabilizes at
• discharging pulses preferably have a magnitude, which is approximately the same as the magnitude of the charging pulses, but which have a duration which
• discharging pulse causes a negative-going spike, which is measured
• second rest periods Selected ones of the second rest periods are extended in time to enable a battery equilibrium to be established and the open circuit voltage of the battery to settle down and reflect an overcharging
• the resistance free terminal voltage of the battery or cell is detected during an interval when the charging current is
• this long time period reaches the programmed maximum charge value for one period, current is simply cut off for the remainder of the fixed long period.
• U.S. Patent No. 6,215,291 discloses a control circuit, having a bandgap reference circuit, which minimizes the charging cycle time of a battery
• U.S. Patent No. 5,166,596 discloses a battery charger having a
• the battery charging method and system should be
• the charging method and system should limit the maximum
• Such batteries may be used in spacecraft and in other applications,
• the charging method and system should be inexpensive, easy to manufacture and use, small and light weight, durable, long lasting,
• the present invention is directed a battery charging method and system that minimizes
• the battery charging method and system is capable of charging one or more batteries
• Such batteries may be used in spacecraft and in other
• the present invention limits the maximum charging voltage and charging current applied to the battery, and taper charges the battery. Additionally, the method and system are inexpensive, easy to manufacture and use, small and light weight, durable, long lasting, reliable, and capable of being used in aerospace and defense applications,
• a battery charging method having features of the present invention comprises: charging
• At least one battery at least one battery at a first voltage for a first time duration; determining state of charge
• a battery charging system having features of the present invention comprises: a current
• the cutoff voltage controller and timer controlling the voltages and controlling time durations of the
• the battery charging method and system regulates the current flow supplied to the
• FIG. 1 is a schematic representation of the steps of a battery charging method
• FIG. 2 is a graphical representation of a battery charging profile
• FIG. 3 is a block diagram of a battery charging system, constructed in accordance with the present invention.
• FIG. 4 is a schematic diagram of a cutoff voltage controller and timer, constructed in accordance with the present invention.
• FIG. 5 is a schematic diagram of an alternate embodiment of a cutoff voltage
• controller and timer constructed in accordance with the present invention
• FIG. 6 is a schematic representation of steps of a method of calibrating the
• FIG. 7 is a schematic representation of steps of a method of calibrating the
• FIG. 8 is a schematic representation of details of a step of the battery charging
• FIG. 9 is a schematic representation of details of another step of the battery charging
• FIG. 10 is a table of typical charging voltage and time durations for batteries having different states of charge
• FIG. 11 is a graphical representation of an actual battery charging profile for a
• FIG. 12 is a graphical representation of an actual battery charging profile for a
• FIGS. 1-12 of the drawings Identical elements in the various figures are identified with the same reference numbers.
• FIG. 1 shows steps of a method of charging batteries 100 of the present invention.
• step 101 Batteries to be charged are charged
• the batteries are evaluated to determine state of charge, i.e., whether the
• the batteries are charged at the first
• step 104 The batteries are then charged at a
• step 103 i.e.,
• the batteries are substantially fully depleted at the end of the first time duration
• step 107 The method of charging batteries 100 ends at step 108.
• FIG. 2 shows a typical charging profile 202 of a silver-based battery, illustrating battery
• Silver-based batteries typically have two plateaus. The first plateau 204,
• plateau region occurs as silver is transformed to monovalent silver oxide
• Silver in the battery is converted to monovalent silver oxide within the
• the total time T tota i may be defined as having time durations, such as, for example, a first time duration Tl, a second time duration T2, and a third
• the first time duration Tl may be defined as the time duration from commencement of charging at a first voltage until the battery is evaluated to determine
• the second time duration T2 may be defined as the time duration from the
• the time duration T3 is defined as the time duration at the first voltage.
• time duration T3' for a time preferably approximately half the alternate time
• the second voltage being substantially equal to the Voltage V2 (209), which is a voltage on or slightly above the second plateau, typically prior to the steeply
• T3 ⁇ T2 with 0.15 ⁇ ⁇ ⁇ 0.25;
• T tota i C/Icc, where C is the capacity of the battery, and Ice is the value of the
• duration T3' which is substantially the time in which a respective one of the
• the method of charging batteries 100 of the present invention may, thus, be optimized
• the method of charging batteries 100 starts at step 101, as shown in FIG.1.
• silver based batteries are, thus, preferably charged at the first voltage being substantially
• V 1 (208), which is a voltage between the first plateau 204 and the
• the batteries are evaluated to determine state of
• T2 ⁇ C/Icc, with 0.55 ⁇ ⁇ ⁇ 0.65, at
• step 104 The batteries are then charged at the second voltage which is substantially
• the steps of the method of charging batteries 100 of the present invention may be any combination of the steps of the method of charging batteries 100 of the present invention.
• a cutoff voltage controller which may be a microcontroller, a computer,
• FIG. 3 shows a block diagram of an embodiment of the present invention, a battery
• cutoff voltage controller and timer 216 which may be a
• V cc (21 ) may be derived.
• the battery charging system 210 of the present invention regulates voltage applied to
• each of batteries Bl (218) and regulates, shapes, and shunts current supplied to each of the batteries Bl (218) at appropriate voltages via the use of the programmable voltage
• the battery charging system 210 may have a plurality of cutoff voltages, which may be
• the batteries Bl (218) which to be charged.
• the batteries Bl (218) may be the same
• 210 may have a plurality of the batteries Bl (218) to be charged and a plurality of the
• Timer controlled switch SI (220) which may be controlled by the cutoff voltage
• controller and timer 216 is in series with current source Ic (221), a plurality of the
• Each of the programmable voltage and current regulators 212 may be any of the programmable voltage and current regulators 212 .
• FIG. 4 shows a typical one of the programmable voltage and current regulators 212
• Control 1 voltage inputs 214 may be derived within the cutoff voltage controller and
• timer 216 may be input directly, either manually or from an external source.
• cutoff voltage controller and timer 216 and controlled by the cutoff voltage controller
• timer 216 may also be derived within the cutoff voltage controller and timer 216 or
• FIG. 5 shows an alternate embodiment of a programmable voltage and current regulator
• FIG. 4 shows a typical one of the programmable voltage and current regulators 212
• programmable voltage and current regulator 212 has an optoisolator U50 (250). The current that arises from a voltage difference between the voltage at the Control 1
• potentiometer resistor R3 (254) being in parallel with upper portion 256 of
• potentiometer resistor R2 (258).
• the potentiometer resistor R3 (254) has a large
• two cutoff voltages may be used in the battery charging system 210.
• the cutoff voltages may be programmed to change as a function of time or may be changed, as a result of other instructions, may have fixed values, or may be changed
• voltages may, for example, be set to the voltage VI (208), between the first plateau 204
• regulators 212 limits the voltages, or cutoff voltages, to which each of the respective
• batteries Bl (218) may be charged.
• the voltages, or cutoff voltages to which the programmable voltage and current regulators are typically set are shown in FIG. 2.
• Voltage VI (208), for example, may be the voltage between the first plateau 204 and
• VI (208) is typically in the range of 1.65 to 1.98 volts and is preferably 1.87 volts.
• the voltage VI (208) is typically in the range of 1.25 to 1.40
• the voltage V2 is preferably 1.35 volts, but other suitable values may be used.
• the voltage V2 is preferably 1.35 volts, but other suitable values may be used.
• (209) may be a voltage on or slightly above the second plateau, typically
• the voltage V2 (209) is in the range of 1.90 to 2.10 volts and is preferably 1.98 volts, however, other suitable
• the voltage V2 (209) may be in the
• FIG. 6 shows steps of a method 300 of calibrating each of the programmable voltage
• potentiometer resistor R3 (254) is then adjusted to achieve a low cutoff voltage
• programmable voltage and cu ⁇ ent regulators 212 ends at step 307, after which the battery Bl (218) may be connected to a respective one of the voltage and current
• step 401 Cu ⁇ ent is allowed to flow without the battery Bl 1 (272) in the battery charging system 210 by setting the timer controlled switch SI 1 (270) to on (step 401).
• step 403 the Control 2 voltage input (232) is then set to
• potentiometer R2 (274) is then adjusted to achieve a mid level cutoff voltage, associated with a mid level voltage V MID ,
• Control 1 voltage input (230) is then again set to a high voltage V HIGH , associated with
• step 406 the Control 2 voltage input (232) is then again set to low voltage
• resistor R4 (278) is then adjusted to achieve a high cutoff voltage across where the
• programmable voltage and cu ⁇ ent regulators 228 ends at step 412, after which the
• battery Bl 1 (272) may be connected to a respective one of the voltage and cu ⁇ ent
• steps 403 and 404 may alternatively be performed in reverse
• steps 406, and 407 may alternatively
• steps 409 and 410 are performed in reverse order or substantially simultaneously, and steps 409 and 410
• the batteries Bl (218) or the batteries Bl 1 (272) may be charged, respectively, in
• cutoff voltages is complete; or once the method 400 of calibrating each of the
• programmable voltage and cu ⁇ ent regulators 228 for use with a plurality of cutoff
• timer controlled switch SI (220) which may be
• programmable voltage and cu ⁇ ent regulators 212 may be individually programmed to
• each of the batteries Bl (218) may be the same and/or different, i.e. the batteries Bl
• (218) may of the same and/or different types, and have the same and/or different
• the cutoff voltage controller and timer 216 which may be a microcontroller, may be
• V cc (217) supplied to the programmable voltage and cu ⁇ ent regulators 212.
• the battery charging system 210 of the present invention may perform steps of a
• FIGS. 1, 8, and 9 show steps of the method of
• FIGS. 8 and 9 Details or smaller steps in FIGS. 8 and 9, which may be incorporated into the steps of
• controller and timer 216 is turned on at step 101-1, after each of the programmable
• the cutoff voltage controller and timer 216 is initialized at step 101-2.
• cutoff voltage controller and timer 216 sets the Control 1 voltage inputs 214 of each of
• the batteries Bl (218) are charged at the first voltage being substantially equal to the
• Voltage VI (208), which is a voltage between the first plateau 204 and the second
• voltage controller and timer 216 which may be a microcontroller.
• the batteries Bl (218) are considered to be substantially fully charged, and the
• T2 ⁇ C/Icc, with 0.60 ⁇ ⁇ ⁇ 0.70, at step 104, as set by the cutoff voltage controller
• Voltage V2 (209), which is a voltage on or slightly above the second plateau, typically
• the batteries Bl (218) are considered to be not substantially fully charged at the
• step 103 end of the first time duration, at step 103, i.e., the batteries are substantially fully
• time duration T2' ⁇ 'C/Icc with 0.80 ⁇ ' ⁇ 0.90, at step 106, as set by the cutoff
• the batteries are then charged at the second voltage, which is substantially equal to the
• FIG. 10 is a table of typical charging voltages and time durations for a typical 3.0 watt-
• FIG. 11 is an actual battery charging profile of a typical 3.0 watt-hour silver zinc battery
• the battery charging profile of FIG. 11 shows the battery at the first cutoff voltage
• first cutoff voltage which is 1.87 volts
• second time duration T2 which is 10
• FIG. 12 is an actual battery charging profile of a typical 3.0 silver zinc battery at a
• the battery charging profile of FIG. 12 shows the battery voltage below the first cutoff
• Each of the batteries of the battery charging system 210 can, thus, be individually
• Battery packs often typically have batteries in series. Thus, all batteries in a battery pack may be individually and independently charged in series to their respective cutoff voltages, thus ensuring a

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Secondary Cells (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (4)

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Citations (3)

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• 2001
  • 2001-12-14 US US10/021,838 patent/US6459243B1/en not_active Expired - Lifetime
• 2002
  • 2002-12-06 CN CNB02816170XA patent/CN1264245C/zh not_active Expired - Fee Related
  • 2002-12-06 JP JP2003567151A patent/JP2005517279A/ja not_active Withdrawn
  • 2002-12-06 DE DE10297404T patent/DE10297404T5/de not_active Ceased
  • 2002-12-06 WO PCT/US2002/039153 patent/WO2003061052A1/en not_active Ceased
  • 2002-12-06 AU AU2002353075A patent/AU2002353075A1/en not_active Abandoned
  • 2002-12-06 KR KR10-2004-7000079A patent/KR20040066085A/ko not_active Withdrawn
  • 2002-12-06 EP EP02790050A patent/EP1454375A4/en not_active Withdrawn
  • 2002-12-06 GB GB0329423A patent/GB2392790B/en not_active Expired - Fee Related
• 2004
  • 2004-06-04 DK DK200400876A patent/DK200400876A/da not_active Application Discontinuation

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