Method and apparatus for charging a battery

Claim 3

The method of Claim 1 wherein said step (a) comprises supplying a controllably varying charging current to said battery; and measuring the voltage produced across the battery output terminals in response to the charging current supplied thereto while said charging current is being supplied.

Claim 4

The method of Claim 2 wherein said step of supplying a controllably varying charging current comprises generating an increasing ramp current followed by a decreasing ramp current; and supplying said ramp currents to said battery.

Claim 5

The method of Claim 3 wherein said step of supplying a controllably varying charging current further comprises sensing when said increasing ramp current attains a predetermined level; maintaining said charging current at said predetermined level for a period of time to induce internal bubbling of said battery; and thereafter generating said decreasing ramp current.

Claim 6

The method of claim 2, wherein said step (a) further comprises determining the slope of said voltage-current characteristic as a function of the change in the measured voltage caused by the change in said charging current.

Claim 7

The method of claim 2, wherein said step (b) comprises changing the rate at which said supplied voltage varies as the charge condition of said battery increases.

Claim 8

The method of claim 6, further comprising the steps of determining the slope of said dynamic voltage-current characteristic in accordance with said measured voltage and supplied charging current, thereby indicating the charge capacity of said battery; sensing the open-circuit voltage of said battery; and comparing the sensed open-circuit voltage .to reference open-circuit voltage levels associated with respective battery charge capacities and thereby determine the charge condition of said battery.

Claim 9

The method of claim 7, wherein said step (b) includes supplying a ramp voltage to said battery having one slope until said battery is charged to its gassing condition, and thereafter supplying said ramp voltage with a second slope.

Claim 10

The method of claim 8, further comprising the steps of determining the charge capacity of said battery as a function of the obtained dynamic voltage-current characteristic thereof; sensing predetermined changes in the slope of said obtained dynamic voltage-current characteristic; and determining that said battery is charged to its gassing condition when said predetermined changes in said slope are sensed at a preselected charge condition for said predetermined charge capacity.

Claim 11

The method of claim 1, wherein step (c) comprises determining the slope of each dynamic voltage-current characteristic obtained; sensing abrupt changes in said determined slope; comparing said abrupt changes in the slope of the last-obtained dynamic voltage-current characteristic to said abrupt changes in the slope of the preceding dynamic voltage-current characteristic; and terminating the charging of said battery if said abrupt changes occur at substantially the same locations of said dynamic voltage-current characteristics.

Claim 12

Apparatus for charging a battery comprising energizing means (18) coupled to said battery (10) to supply energy thereto; sensing means (26; 34) coupled to said battery to sense voltage thereacross and current thereto; and control means (12, 14; 30) coupled to said energizing means and to said sensing means for controlling the energy supplied to said battery by said energizing means during a test cycle and responsive to at least one of the voltage and current sensed during said test cycle to obtain the dynamic voltage-current characteristic of said battery and to determine the charge condition of said battery as a function of said dynamic voltage-current characteristic; said control means (12, 14; 30) being operative during a charge cycle for controlling said energizing means to supply a gradually varying voltage to said battery, substantially without controlling the current supplied thereto, at a rate related to said dynamic voltage-current characteristic; and said control means being operative to alternate vetween said test cycle and said charge cycle until the latest dynamic voltage-current characteristic obtained thereby is substantially identical to the preceding dynamic voltage-current characteristic.

Claim 13

Apparatus for charging a battery comprising energizing means (18) coupled to said battery (10) to supply energy thereto; sensing means (26; 34) coupled to said battery to sense voltage thereacross and current thereto; and control means (12, 14; 30) coupled to said energizing means and to said sensing means for controlling the energy supplied to said battery by said energizing means during a test cycle and responsive to at least one of the voltage and current sensed during said test cycle to obtain the dynamic voltage-current characteristic of said battery and to determine the charge condition of said battery as a function of said dynamic voltage-current characteristic; said control means (12, 14; 30) being operative during a charge cycle for controlling said energizing means to supply a gradually varying voltage to said battery, substantially without controlling the current supplied thereto, at a rate related to said dynamic voltage-current characteristic; and said control means being operative to alternate vetween said test cycle and said charge cycle until the latest dynamic voltage-current characteristic obtained thereby is substantially identical to the preceding dynamic voltage-current characteristic.

Claim 14

The apparatus of claim 11, wherein said energizing means (18) comprises means for supplying current and voltage to said battery, and said control means (12, 14; 30) controls said energizing means to supply a controllably varying charging current to said battery during said test cycle.

Claim 15

The apparatus of claim 12, wherein said control means is responsive to said voltage sensed during said test cycle to obtain said dynamic voltage-current characteristic of said battery as a function of said sensed voltage and said supplied charging current.

Claim 16

The apparatus of claim 13, wherein said means for supplying current to said battery comprises current ramp generating means, responsive to said control means, for generating a current ramp which increases with respect to time followed by a current ramp which decreases with respect to time.

Claim 17

The apparatus of claim 14, wherein said control means is operative to control said current ramp generating means to generate a substantially constant current of predetermined magnitude following said increasing current ramp and preceding said decreasing current ramp.

Claim 18

The apparatus of claim 15, wherein said constant current magnitude is sufficient to induce internal bubbling in said battery.

Claim 19

The apparatus of claim 12, wherein said control means controls said energizing means to reduce the rate at which said voltage is supplied by said energizing means to said battery during said charge cycle as the charge condition of said battery increases.

Claim 20

The apparatus of claim 17, wherein said energizing means generatesa ramp voltage during said charge cycle; and wherein said control means is operative to reduce the slope of said ramp voltage when said sensing means senses that the voltage produced across said battery during said test cycle exceeds a predetermined gassing voltage.

Claim 21

The apparatus of claim 11, wherein said control means comprises programmed data processing means (30) for determining said dynamic voltage-current characteristic of said battery as a function of the voltage sensed by said sensing means and the energy supplied by said energizing means, for determining the charge condition of said battery as a function of said voltage sensed by said sensing means when no energy is supplied to said battery, for varying the rate at which said voltage is supplied to said battery by said energizing means as a function of said determined charge condition, and for comparing successive ones of said determined dynamic voltage-current characteristic to determine when they are substantially identical.

Claim 22

Apparatus for charging a battery comprising energizing means (18) coupled to said battery (10) to selectively supply current and voltage thereto; sensing means (26;34) coupled to said battery to sense voltare thereacross; and data processing means (30) programmed to alternate repeatedly between a test cycle and a charge cycle and for controlling said energizing means during each cycle, said data processing means determining the charge condition of said battery as a function of the voltage sensed during a test cycle and terminating further charge cycles when said battery is determined to be fully charged.

Claim 23

Apparatus for charging a battery comprising energizing means (18) coupled to said battery (10) to selectively supply current and voltage thereto; sensing means (26;34) coupled to said battery to sense voltare thereacross; and data processing means (30) programmed to alternate repeatedly between a test cycle and a charge cycle and for controlling said energizing means during each cycle, said data processing means determining the charge condition of said battery as a function of the voltage sensed during a test cycle and terminating further charge cycles when said battery is determined to be fully charged.

Claim 24

The apparatus of claim 20, wherein said data processing means is programmed to control said energizing means during each test cycle to supply a gradually increasing current followed by a gradually decreasing current to said battery.

Claim 25

The apparatus of claim 21, wherein said data processing means is programmed to derive a dynamic voltage-current characteristic as a function of the voltage sensed across said battery and the current supplied to said battery during said test cycle.

Claim 26

The apparatus of claim 20, wherein said data processing means is programmed to control said energizing means during each charge cycle to supply a ramp voltage to said battery,said ramp voltage having an initial level and increasing at a controllable rate.

Claim 27

The apparatus of claim 23, wherein said data processing means includes memory means for storing data representing different initial voltage levels correlated with determined battery charge conditions; and said data processing means is programmed to select the initial voltage level of said ramp voltage as a function of the charge condition of said battery determined during a test cycle.

Claim 28

Apparatus for charring a battery comprising energising means (18) coupled to said battery (10) to selectively supply current and voltage thereto; sensing means (26:34) coupled to said battery to sense voltage thereacross; and data processing means (30) programmed to repeatedly establish and alternate between a test cycle and a charge cycle and for controlling said energizing means during each cycle, said data processing means including memory means (36) for storing charge capacity data representing charge capacities of different batteries, gas voltage data representing the gas voltage levels of said batteries, charge level data representing the charge levels of said batteries as a function of the battery voltage thereof, charging voltage data representing predetermined parameters relating to charging voltages as a function of the battery voltage, maximum current data representing the maximum level of test currents as a function of battery charge capacity, and fault data representing predetermined battery fault conditions as a function of battery voltage; said data processing means being further programmed to control said energizing means during a test cycle to supply a test current having gradually increasing and decreasing portions and to obtain a dynamic voltage-current characteristic as a function of said supplied current and the voltage across said battery sensed by said sensing means while said current is supplied; said data processing means being further programmed to determine the number of cells included in said battery as a function of said sensed voltage when said current is substantially zero; said data processing means being further programmed to determine the slope of said dynamic voltage-current characteristic and to derive the charge capacity of said battery as a function of the determined number of cells and determined slope; said data processing means being further programmed to compare said sensed voltage when said current is substantially zero to said stored charge level data to derive the charge level of said battery; said data processing means being further programmed to compare said obtained dynamic voltage-current characteristic to said fault data to indicate the presence of a battery fault condition; said data processing means being further programmed to control said energizing means during a charge cycle to supply a charging voltage to said battery in accordance with said stored charging voltage data, dependent upon said battery voltage sensed during said test cycle, and said derived charge level of said battery; and said data processing means being further programmed to compare the latest dynamic voltage-current characteristic obtained with the preceding dynamic voltage-current characteristic and to terminate further charge cycles when the compared characteristics are substantially identical.

Claim 29

Apparatus for charring a battery comprising energising means (18) coupled to said battery (10) to selectively supply current and voltage thereto; sensing means (26:34) coupled to said battery to sense voltage thereacross; and data processing means (30) programmed to repeatedly establish and alternate between a test cycle and a charge cycle and for controlling said energizing means during each cycle, said data processing means including memory means (36) for storing charge capacity data representing charge capacities of different batteries, gas voltage data representing the gas voltage levels of said batteries, charge level data representing the charge levels of said batteries as a function of the battery voltage thereof, charging voltage data representing predetermined parameters relating to charging voltages as a function of the battery voltage, maximum current data representing the maximum level of test currents as a function of battery charge capacity, and fault data representing predetermined battery fault conditions as a function of battery voltage; said data processing means being further programmed to control said energizing means during a test cycle to supply a test current having gradually increasing and decreasing portions and to obtain a dynamic voltage-current characteristic as a function of said supplied current and the voltage across said battery sensed by said sensing means while said current is supplied; said data processing means being further programmed to determine the number of cells included in said battery as a function of said sensed voltage when said current is substantially zero; said data processing means being further programmed to determine the slope of said dynamic voltage-current characteristic and to derive the charge capacity of said battery as a function of the determined number of cells and determined slope; said data processing means being further programmed to compare said sensed voltage when said current is substantially zero to said stored charge level data to derive the charge level of said battery; said data processing means being further programmed to compare said obtained dynamic voltage-current characteristic to said fault data to indicate the presence of a battery fault condition; said data processing means being further programmed to control said energizing means during a charge cycle to supply a charging voltage to said battery in accordance with said stored charging voltage data, dependent upon said battery voltage sensed during said test cycle, and said derived charge level of said battery; and said data processing means being further programmed to compare the latest dynamic voltage-current characteristic obtained with the preceding dynamic voltage-current characteristic and to terminate further charge cycles when the compared characteristics are substantially identical.