Battery charging method and system with three-stage temperature-compensated charge profile
First Claim
1. A method of charging a rechargeable battery, comprising:
- providing, during a ‘
bulk stage’
, a regulated charge current to said battery until the voltage across said battery increases to a predetermined ‘
absorption stage voltage limit’
at which time charging transitions to an ‘
absorption stage’
;
providing, during said ‘
absorption stage’
, a charge current to said battery which maintains the voltage across said battery at said predetermined ‘
absorption stage voltage limit’
;
determining when a first condition occurs, said first condition being when said charge current falls to a predetermined ‘
absorption stage current threshold’
value;
determining when a second condition occurs, said second condition being when the charge in ampere-hours delivered to said battery during said absorption stage rises to a predetermined ‘
absorption stage charge threshold’
value;
determining when a third condition occurs, said third condition being when the difference in charge between two successive fixed time intervals of equal duration becomes approximately zero;
transitioning charging to a ‘
float stage’
when any of said three conditions are met; and
providing, during said ‘
float stage’
, a constant charge current to said battery such that the voltage across said battery varies with the temperature of said battery.
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Accused Products
Abstract
A battery charging method and system with a temperature-compensated charge profile requires that, during a ‘bulk stage’, a regulated constant charge current is provided to the battery until the voltage across it increases to a predetermined ‘absorption stage voltage limit’, at which time charging transitions to an ‘absorption stage’. During the absorption stage, a charge current is provided which maintains the voltage across the battery at the absorption stage voltage limit, until: 1) the charge current falls to a predetermined current threshold, 2) the charge delivered to the battery during the absorption stage reaches a predetermined charge threshold, or 3) the difference in charge between two successive intervals of equal duration becomes zero, at which time charging transitions to a ‘float stage’. During the ‘float stage’, a regulated constant charge current is provided, such that the voltage across the battery varies with the temperature of the battery.
16 Citations
24 Claims
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1. A method of charging a rechargeable battery, comprising:
-
providing, during a ‘
bulk stage’
, a regulated charge current to said battery until the voltage across said battery increases to a predetermined ‘
absorption stage voltage limit’
at which time charging transitions to an ‘
absorption stage’
;providing, during said ‘
absorption stage’
, a charge current to said battery which maintains the voltage across said battery at said predetermined ‘
absorption stage voltage limit’
;determining when a first condition occurs, said first condition being when said charge current falls to a predetermined ‘
absorption stage current threshold’
value;determining when a second condition occurs, said second condition being when the charge in ampere-hours delivered to said battery during said absorption stage rises to a predetermined ‘
absorption stage charge threshold’
value;determining when a third condition occurs, said third condition being when the difference in charge between two successive fixed time intervals of equal duration becomes approximately zero; transitioning charging to a ‘
float stage’
when any of said three conditions are met; andproviding, during said ‘
float stage’
, a constant charge current to said battery such that the voltage across said battery varies with the temperature of said battery. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A battery charging system, comprising:
-
circuitry arranged to provide a charge current to and a voltage across a battery to be charged; and a controller arranged to operate said circuitry such that; during a ‘
bulk stage’
, said circuitry provides a regulated charge current to said battery until the voltage across said battery increases to a predetermined ‘
absorption stage voltage limit’
at which time charging transitions to an ‘
absorption stage’
;during said ‘
absorption stage’
, said circuitry provides a charge current to said battery which maintains the voltage across said battery at said predetermined ‘
absorption stage voltage limit’
,said controller arranged to detect at least three conditions, a first condition being when said charge current falls to a predetermined ‘
absorption stage current threshold’
value, a second condition being when the amp-hour product delivered to said battery during said absorption stage reaches a predetermined ‘
absorption stage charge threshold’
value, a third condition being when the difference in charge between two successive fixed time intervals of equal duration becomes approximately zero, said controller further arranged to transition charging to a ‘
float stage’
when any of said first, second or third conditions are detected; andduring said ‘
float stage’
, said circuitry provides a constant charge current to said battery such that the voltage across said battery varies with the temperature of said battery. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification