Classifications

• • 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
  • H02J7/007—Regulation of charging or discharging current or voltage
  • H02J7/00711—Regulation of charging or discharging current or voltage with introduction of pulses during the charging process
• • 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]
• • 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
  • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
  • H01M10/484—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring electrolyte level, electrolyte density or electrolyte conductivity
• • 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

• This invention relates to battery chargers and, more particularly, to a method and an apparatus for controlling the charging process for a battery and for terminating the charging process.
• One method of determining the state of charge is to detect the occurrence of minus delta V and to terminate the charging process on such occurrence. However, this method will reduce the battery life because the minus delta V occurs when an excess of oxygen is produced by the positive electrode and consumed by the negative electrode. As a consequence, this method allows the battery temperature to rise and also allows pressure to build up inside the battery.
• Another method of determining when to terminate the charging process has been used when the battery is charged by forcing pulses of current though the battery and applying a discharge pulse after each charging pulse.
• the charging process is terminated either in response to the average discharge current during the discharge pulse or in response to the ratio of energy removed by the discharge pulse compared to the energy provided to the battery during preceding charging pulse.
• discharge voltage value there is not a strong relationship between discharge voltage value and the state of charge of the battery.
• Another method of terminating the charging process provides for sampling the terminal voltage of the battery between charging pulses a predetermined time after the beginning of the charge.
• Another method provides for measuring the battery voltage when a charging current is being applied and measuring the battery voltage during a discharging current. The two voltage measurements are compared and the charging process is terminated when there is a predetermined difference between these voltages.
• the predetermined difference must be selected depending upon the type of battery being charged and the capacity of the battery being charged.
• this method does not prevent the oxygen generating coincident with overcharging because it does not accurately determine the state of charge of the battery.
• the no-load (“resistance free”) terminal voltage of the battery is measured after the end of a charging pulse. This voltage is compared with a reference voltage to determine the charging current.
• the reference voltage may be dependent upon, for example the ambient temperature, the internal temperature, the internal pressure, the charging current, or a change in value in the charging current.
• the measurement of the resistance free voltage must occur when all the cells in the battery are in an equilibrium mode. If an equilibrium condition has not been obtained then the voltage measurement of open circuit voltage can be different depending upon the time from the end of the previous charging pulse. The equilibrium time depends on the charging current and the mass transfer capability of the battery.
• the accuracy of the measurement of the resistance free voltage will depend upon the concentration of the electrolyte in the battery and the age of the battery.
• the concentration of electrolyte will change, due to the porous structure of the plates surface, so measurement of the open circuit voltage milliseconds after the end of a charging pulse will not produce accurate results.
• the battery can be overheated or destroyed.
• selection of the proper reference voltage may be difficult or very time-consuming. Any method which rapidly charges a battery must account for the constantly changing parameters of the battery, such as internal resistance, polarization resistance, mass transfer condition and temperature.
• a rapid charging system typically uses a tapering current to avoid an overcharge condition and avoid gas production.
• U.S. Patent No. 5,307,000 discloses using multiple discharge pulses between each charging pulse and provides for rapidly charging a battery with high charging pulse currents for a longer period of time, without marginal voltages per cell and heat production. Without a plurality of depolarization pulses the voltage on the battery will rise very fast, due to a rapidly increasing concentration of electrolyte around the electrodes, particularly at the end of a charging pulse.
• a rapid charging process must be based on a reliable and precise method of charging control and charge termination.
• Some previous charging methods have relied upon temperature cutoff, or other methods that are not appropriate and/or uniform for all types of batteries, and methods that even required selection of the battery capacity even when used for charging the same battery type (lead-acid, NiCd, NiMH).
• Other previous charging methods have relied upon voltage cutoff.
• a fixed voltage threshold is not reliable because the proper voltage threshold varies, depending upon the condition of the battery, the temperature, and the battery's previous use and charge history.
• the preferred technique for rapidly charging a battery involves forcing a high charging current into the battery, preferably by applying a series of charging and depolarizing pulses to the battery. As the charging process becomes faster and the instantaneous charging currents become higher, it is much more difficult to determine when the battery is fully charged and when the optimum time to terminate or modify the charging process occurs. Without precisely knowing when the battery is fully charged, both charging time and energy are wasted due to overcharging of the batter ⁇ '. However, as stated above, overcharging causes gassing, generates heat, and increases pressure within the battery, thereby causing damage to the battery or potentially initiating a catastrophic thermal runaway condition in the battery.
• the battery may not be able to accept the full current from a charging pulse.
• some of the charge current delivered during the charging pulse causes gassing and heating.
• terminating the rapid charging process at this time would be premature because the battery is not fully charged and is still amenable to a rapid charging process, but at a lower charging current. Therefore, there is a need for a method of modifying a rapid charging process, as the battery is becoming charged, so as to continue rapidly charging the battery in an efficient manner.
• the present invention is directed to accurately determining when a battery is charged. This allows a rapid charging process to be used as long as possible, thereby substantially charging the battery, but terminates the rapid charging process at a point which avoids overcharging the battery and thus avoids wasted charging time and energy and damage to the battery.
• a charging pulse is applied to the battery and then at least two discharging (depolarization) pulses are applied to the battery.
• the battery voltage is measured at a predetermined point in a rest (wait) period after a first depolarizing pulse and at the same relative point in a rest period after a second depolarizing pulse.
• the depolarizing pulse is created by applying a load across the terminals of the battery and is typically of a significantly shorter duration than the charging pulse.
• the lead sulfate in the battery solution is converted into lead, lead oxide, and electrolyte ions.
• the lead and lead oxide are deposited on the respective electrodes.
• the electrolyte ions are formed at the electrodes and surround the electrodes. These electrolyte ions are dispersed by a transport phenomena due to the difference in the concentrations of the ions around the electrodes and the concentrations of the ions in the solution.
• the concentration of the electrolyte is small.
• the electrolyte ions formed around the electrodes are rapidly dispersed into the solution.
• the difference in the concentrations is small and thus the ions disperse more slowly.
• the ions form a barrier around the electrodes and prevent the electrodes from efficiently accepting another charging pulse.
• the charging voltage must be increased in order to force the battery to accept the same amount of charging current.
• increasing the charging voltage causes the water in the battery to disassociate into hydrogen gas and oxygen gas.
• the state of charge of the battery can be determined by measuring the open circuit voltage of the battery during rest periods following discharge pulses. If the open circuit voltage is approximately the same from one rest period to a subsequent rest period, then the battery is not being overcharged so the charging current need not be changed. If the open circuit voltage decreases from one rest period to a subsequent rest period, then the battery is being overcharged or is being charged at a rate higher than the battery can accept so the charging current should be decreased or the charging process terminated.
• the charging current should be reduced to the level that the battery will efficiently accept.
• the battery is determined to be efficiently accepting a charge and the charging current need not be changed as long as the second voltage measurement is approximately the same as the first voltage measurement.
• the battery is determined to be mostly charged and the charging current should be reduced when the second voltage measurement is less than the first voltage measurement by some predetermined voltage difference ( ⁇ V).
• ⁇ V predetermined voltage difference
• the present invention provides a method for charging a battery.
• the method includes the steps of applying a charging pulse which provides an average charging current, applying a first depolarizing pulse, waiting for a first rest period, measuring the voltage of the battery at a predetermined point within the first rest period, applying a second depolarizing pulse, waiting for a second rest period, measuring the voltage of the battery at the predetermined point within the second rest period, determining a difference between the voltage at the predetermined point within the first rest period and the voltage at the predetermined point within the second rest period, and changing the average charging current depending upon the amount and polarity of this difference.
• the steps of applying the charging pulse, applying the first and second depolarizing pulses, waiting for the first and second rest periods, and measuring the voltages within the first and second rest periods are repeated if the difference is within specified limits.
• the charging pulse has a charging pulse duration and the step of changing the average charging current comprises changing the charging pulse duration.
• the charging pulse has a charging pulse current amplitude and the step of changing the average charging current comprises changing the charging pulse current amplitude.
• the charging pulse has a charging pulse repetition rate and the step of changing the average charging current comprises changing the charging pulse repetition rate.
• each depolarizing pulse has a depolarizing pulse current amplitude and the method further includes changing the depolarizing pulse current amplitude when the average charging current is changed.
• each depolarizing pulse has a depolarizing pulse duration and the method further includes changing the depolarizing pulse duration when the average charging current is changed.
• a number of the depolarizing pulses follows each the charging pulse and the method further includes changing the number of the depolarizing pulses when the average charging current is changed.
• the present invention also provides a method for charging a battery by a pulse charging process.
• the method includes applying a charging pulse, applying a first depolarizing pulse, waiting for a first rest period, measuring the voltage of the battery at a predetermined point within the first rest period, applying a second depolarizing pulse, waiting for a second rest period, measuring the voltage of the battery at the predetermined point within the second rest period, determining a difference between the voltage at the predetermined point within the first rest period and the voltage at the predetermined point within the second rest period, and terminating the pulse charging process if the difference is greater than a predetermined threshold.
• the present invention also provides a method for determining the condition of a battery.
• the method includes applying a charging pulse to the battery, applying a first depolarizing pulse to the battery, waiting for a first rest period, measuring the voltage of the battery at a first predetermined point within the first rest period, measuring the voltage of the battery at a second predetermined point within the first rest period, applying a second depolarizing pulse to the battery, waiting for a second rest period, determining a difference between the voltage at the first predetermined point and the voltage at the second predetermined point, and indicating that water should be added to the battery if the difference is greater than a predetermined threshold then.
• the present invention also provides a method for terminating the charging process for a battery.
• the method includes applying a charging pulse to the battery, applying a first depolarizing pulse to the battery, waiting for a first rest period, measuring the voltage of the battery at a first predetermined point within the first rest period, measuring the voltage of the battery at a second predetermined point within the first rest period, applying a second depolarizing pulse to the battery, waiting for a second rest period, measuring the voltage of the battery at a first predetermined point within the second rest period, measuring the voltage of the battery at a second predetermined point within the second rest period, determining a first difference between the voltage at the first predetermined point within the first rest period and the voltage at the second predetermined point within the first rest period, determining a second difference between the voltage at the first predetermined point within the second rest period and the voltage at the second predetermined point within the second rest period, and terminating the charging process if both the first difference is greater than a predetermined threshold and the second difference is greater than the predetermined threshold.
• FIG. 1 is a block diagram of a battery charging circuit used in the present invention.
• Figures 2A-2B show waveforms which illustrate a battery charging process and how the state of charge of the battery is determined by comparing voltage measurements taken in different rest periods.
• Figure 3 is a flow chart illustrating the process of determining the state of charge of the battery.
• Figure 4 shows waveforms which illustrate a battery charging process and how the condition of the battery is determined.
• Figure 5 is a modification of the flow chart of Figure 3 which illustrates the process of determining the condition of the battery.
• FIG. 1 is a block diagram of a battery charging circuit used in the present invention.
• the battery charging and discharging circuit 10 comprises a keypad 12, a controller 13, a display 14, a charging circuit 15, a discharging (depolarization) circuit 16, and a current monitoring circuit 20.
• the keypad 12 is connected to the "K" input of the controller 13 and allows the user to input specified parameters such as the battery type (lead acid, NiCd, NiMH, etc.) and other relevant information, such as nominal battery voltage or number of cells in series.
• the keypad 12 may be a keyboard, dial pad, array of switches, or other device for entering infoimation.
• the controller 13 may be preprogrammed with the parameters for a plurality of battery types. In this case, the user would simply enter a battery type, such as a model number, and the controller 13 would automatically use the parameters appropriate for that battery type.
• the display 14 is connected to the "S" output of the controller 13 and displays the information, choices, parameters, etc., for the operator, and provides for audible and visible alarms or alerts for the operator.
• the “C” output of the controller 13 is connected to the charging circuit 15.
• the charging circuit 15 provides a charging current to the battery 11.
• the charging circuit 15 may be configured by the controller 13 to perform as a constant voltage source or as a constant current source.
• the "D" output of the controller 13 is connected to the discharging (depolarization) circuit 16, which may be configured by the controller 13 to provide a constant depolarization current to the battery 11 , apply a selected load to the battery 11, or apply a lower voltage or a reverse voltage to the battery 11.
• the pulse width of the pulses provided by circuits 15 and 16 are controlled by the controller 13.
• the output of the charging circuit 15 and the discharging circuit 16 are connected to the positive terminal of the battery 11 via conductor 21.
• the negative terminal of the battery 11 is connected to circuit ground through a current monitoring resistor 20.
• Current flowing into or out of the battery 1 1 may therefore be determined by measuring the voltage across the current monitoring resistor 20 on conductor 22.
• the current monitoring resistor 20 therefore functions as a current monitor and current limiter. Of course, other devices may be used to determine battery current.
• Battery voltage is monitored by measuring the voltage between conductor 21 and circuit ground.
• the effects of the current monitoring resistor may be eliminated by measuring the voltage between conductors 21 and 22, or by subtracting the voltage on conductor 22 from the voltage on conductor 21.
• Conductors 21 and 22 are connected to the "V" and "I" input, respectively, of the controller 13.
• Battery presence may be determined by activating the charging circuit 15 and monitoring the output of the current monitoring resistor 20 to determine if charge current is flowing, by activating the discharging circuit 16 and monitoring the output of the current monitoring resistor 20 to determine if charge current is flowing, by monitoring the voltage with both circuits 15 and 16 deactivated to determine if a battery is present, etc.
• Temperature sensor 23 monitors the temperature of the battery 11 so that the controller 13 can adjust the magnitude, number, and duration of the charging pulses and the depolarizing pulses and the duration of the rest periods in order to maintain the desired battery temperature. Temperature sensor 23 preferably is immersed in the electrolyte solution of each battery cell to accurately report the internal battery temperature, even though only one is shown in the drawing. Temperature sensor 23 can be a thermostat, thermistor, thermocouple, or the like and is connected to the "T" input of the controller 13.
• the controller 13 comprises a microprocessor, a memory, at least part of which contains operating instructions for the controller 13, timers, and an analog-to-digital converter.
• a microprocessor-based controller is advantageous because a microprocessor can make very rapid decisions, store voltage and current measurement data, and perform calculations on data, such as averaging, comparing, and detecting peaks.
• the timers which can be discrete or implemented by the microprocessor, may be used for controlling the duration of any charging pulses, depolarizing pulses, or rest periods as well as providing time references between consecutive depolarizing pulses or rest periods.
• the analog-to-digital converter which can be discrete or implemented by the microprocessor, may be used to convert the voltage or current signals into a form usable by the digital microprocessor.
• a digital controller is discussed because it is the preferred embodiment, but an analog controller may also be used to implement the present invention.
• FIGS 2A-2B show waveforms which illustrate a battery charging process and how the state of charge of the battery is determined.
• the state of charge is determined by comparing voltage measurements taken in different rest periods.
• the voltage and current waveforms generally illustrate the charging process which applies one or more charging pulses Cl , preferably followed by a rest period CW1 , and a plurality of depolarizing pulses Dl - D3, each depolarizing pulse Dl - D3, preferably followed by a rest period DW1 - DW3, respectively.
• the charging pulses and depolarizing pulses are illustrated as rectangular pulses but it should be appreciated that this is often not the case in actual practice and thus the present invention should be understood to include, but not be limited to, rectangular waveforms.
• the charging pulses Cl, Cl' are shown to have the same pulse width and the same charge current amplitude IA, and the depolarizing pulses Dl - D3 are shown to have the same pulse width and the same discharge current amplitude IB. Additionally, the number of depolarizing pulses shown is purely for convenience and not by way of limitation.
• the rest periods CW1 and DW1 - DW3 are shown to be of the same duration only for convenience and not by way of limitation. The controller 13 may alter the duration of such rest periods based on monitored changes in the state of charge of the battery.
• VI and V2 are output voltage measurements of the battery taken when the battery is in an open circuit configuration during rest periods DW1 and DW2, respectively. It should be understood that the first output voltage measurement VI can be made in the beginning, middle, or end of the rest period DW1, so long as the subsequent output voltage measurement V2 is taken at the same relative point in the next rest period DW2.
• the voltage levels during rest periods DW1 - DW3 are measured and evaluated by the present invention.
• FIG. 3 is a flowchart for determining if a battery is charged by comparing voltage measurements taken during one or more rest periods.
• the initial charging parameters are set by the user, such as the battery voltage or number of cells in the battery and the discharge rating (C) for the battery.
• the controller 13 determines the charging current IA and the depolarizing current IB for the battery. This may be based upon a look-up table or an equation, as preferred.
• the controller 13 applies a charging pulse Cl of current amplitude IA to the battery, preferably but not necessarily followed by a rest period CW1, and then applies a depolarizing pulse Dl to the battery of current amplitude IB to the battery.
• the controller 13 waits for a predetermined period of time DWl and measures an output voltage VI of the battery at a predetermined point in the rest period DWl . Controller 13 then applies another depolarizing pulse D2 of current amplitude IB to the battery. The controller again waits for a predetermined period of time DW2 and measures another output voltage V2 of the battery at a corresponding predetermined point in the second rest period DW2. It should be understood that the first output voltage measurement VI can be made in the beginning, middle, or end of the first rest period DWl , so long as the subsequent output voltage measurement V2 is taken at the same relative point, relative to the beginning of the rest period, in the next rest period DW2.
• Decision 309 tests whether the difference (VI -V2) is greater than some maximum difference voltage (VDMAX). If not, then the battery is not yet charged and the average charging current does not have to be adjusted. In this case controller 13 will proceed to step 313.
• step 311 the controller 13 decreases the average charging current. Controller 13 then proceeds to step 313.
• step 313 the controller 13 determines whether to terminate the pulse charging process.
• the pulse charging cycle may be terminated for any one of several different reasons. For example, the charging time set by the user may have expired, or the battery temperature may be outside of an acceptable range, or the amplitude of the charging current IA may have been reduced to C/10 or less.
• step 315 the controller 13 will terminate the pulse charging process and will switch to another charging process, for example, trickle charging if termination is because the charging current is C/10, or the controller 13 will stop the charging process entirely, for example, if termination is because time has expired or the temperature is unacceptable. Also, a visual or audible indication of termination of the charge process may be provided to the operator. If, at step 313, controller 13 determines that the pulse charging process is not to be terminated then controller 13 will retum to step 303.
• Figure 4 shows waveforms which illustrate a battery charging process and how the condition of the battery is determined. In this procedure, the open circuit battery voltage is measured at the beginning and at the end of the rest periods.
• the voltage is shown as essentially constant during a rest period.
• the measurements are made during the first rest period DWl.
• FIG. 5 is a flow chart illustrating a variation of the process of determining the condition of the battery.
• step 513 provides an explanation of some of the termination steps of decision 313.
• step 513 additional voltage measurements V5, V6, V7, and V8 are taken, and voltage differences VD1 and VD2 are determined.
• the controller 13 determines whether the voltage difference VD1 is greater than a predetermined maximum difference VD1MAX. If so, then in step 513B the controller 13 initiates an alarm to signal the operator to add water to the battery and then preferably terminates the charging process. If not, then in decision 513C the controller determines whether VD1 is greater than a predetermined maximum VD2MAX and VD2 is also greater than VD2MAX. If both conditions are met then the controller 13 terminates the charging process. The controller 13 may also signal the operator of the termination. If not then the controller 13 returns to step 503.
• the charging current may be adjusted by adjusting IA, by adjusting the duration of the charging pulse, by adjusting the repetition rate of the charging pulses, by adjusting the number or the duration of the depolarization pulses, or by adjusting the duration of one or more of the rest periods CW1 , DWl , DW2, etc.
• the depolarizing current is adjusted similarly, such as by adjusting IB, by adjusting the duration of the depolarizing pulses, or by adjusting the number of depolarizing pulses between each charging pulse.
• IA is 2.4 amperes for 150 milliseconds
• IB is 5 amperes for 2 milliseconds
• DWl and DW2 are 12 milliseconds
• the repetition rate of the charge pulse (approximately 2 charge pulses per second) is such that the average charging current is 0.75 amperes (about 1.2C).
• CW1 may be used or may not be present.
• the pulse charging process will be terminated when the average charging current drops to 0.0623 amperes (0.1C).
• IA is 100 amperes and IB is 250 amperes
• the duration of the charge pulse is such that the average charging current is 60 amperes (about 1.2C), and the pulse charging process will be terminated when the average charging current drops to 5.2 amperes (0.1C).
• the present invention is not so limited.
• the battery voltages may be measured for any two consecutive or non- consecutive discharge rest periods which are not separated by a charging pulse.
• DW2 and DW3 may be used, or DWl and DW3 may be used.
• the depolarization pulses may have the same amplitude or may have different amplitudes. Likewise, the depolarization pulses may have the same duration or may have different durations. In addition, the rest periods may have the same duration or may have different durations.
• the present invention has been described with particularity with respect to sealed lead-acid batteries, the present invention is not so limited.
• the present invention is also useful for other types of batteries, for example, NiCd, NiMH, nickel-iron, nickel-zinc, silver-zinc, lithium-metal oxide, lithium ion-metal oxide, non-sealed lead-acid, etc. It will be appreciated from the above that the present invention provides a method and an apparatus for rapidly charging a battery in a manner which does not cause overheating of the battery.
• the present invention provides a method and an apparatus for charging a battery at a rate that the battery can accept without damage.
• the present invention also provides a method and an apparatus for determining the condition of a battery, including determining whether water should be added to the battery.

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

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• 1996
  • 1996-07-10 NZ NZ312602A patent/NZ312602A/en unknown
  • 1996-07-10 AU AU64597/96A patent/AU710799B2/en not_active Ceased
  • 1996-07-10 JP JP9505949A patent/JPH11509078A/ja active Pending
  • 1996-07-10 IL IL12282196A patent/IL122821A0/xx unknown
  • 1996-07-10 CN CN96195426A patent/CN1078397C/zh not_active Expired - Fee Related
  • 1996-07-10 EP EP96923731A patent/EP0846361A4/en not_active Withdrawn
  • 1996-07-10 KR KR1019980700178A patent/KR19990028876A/ko not_active Application Discontinuation
  • 1996-07-10 BR BR9609599A patent/BR9609599A/pt not_active Application Discontinuation
  • 1996-07-10 EA EA199800053A patent/EA000240B1/ru not_active IP Right Cessation
  • 1996-07-10 CA CA002226411A patent/CA2226411A1/en not_active Abandoned
  • 1996-07-10 WO PCT/US1996/011466 patent/WO1997003489A1/en not_active Application Discontinuation
• 1998
  • 1998-01-09 NO NO980111A patent/NO980111L/no not_active Application Discontinuation

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