Invalidity dossier
US 6097172
Added 9/21/2026, 9:36:17 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 6,097,172 A
Title: Method and apparatus for determining when to terminate charging of a battery
Patent number / application: US 6,097,172 A (application US 08/698,050)
Inventors: Yury M. Podrazhansky and Boris Tsenter
Assignee: Advanced Charger Technology Inc. (original assignee; assignment recorded 1996-08-15 and 1997-01-13)
Dates: Priority/filing date 1996-08-15; granted/publication date 2000-08-01; anticipated expiration 2016-08-15. Legal status listed as "Expired – Fee Related."
Purpose: The invention relates generally to charging a battery and, more particularly, to determining when charging of a sealed battery should be terminated. It aims to enable rapid charging without significant overcharging and with reduced electrolyte decomposition and gas evolution, avoiding problems in temperature-sensing, negative-voltage-slope, and timed-termination approaches.
Plain-language scope: Charging uses charge pulses followed by depolarizing (discharge) pulses and rest periods. From time to time, a second rest period is extended (about 20–250 ms, typically ~150 ms) so the battery can reach equilibrium and its open circuit voltage (Voc) can be measured. Two Voc measurements are compared during the extended rest period; a negative change (negative slope) indicates gas/oxygen evolution and a full charge, and charging is terminated. Measurements may occur at prescribed intervals (e.g., every several minutes early, then every 30–40 seconds after a predetermined voltage is reached). The technique is described for nickel-cadmium, nickel-metal-hydride, nickel-hydrogen, nickel-zinc, manganese-zinc, and sealed silver-zinc cells. FIG. 2 is an illustrative microprocessor flow diagram; FIG. 4 is a circuit block diagram.
Classification: H02J 7/00, H02J 7/90, H02J 7/927; H01M 10/42, H01M 10/44.
Source: https://patents.google.com/patent/US6097172/en
Not established by the excerpt: The full text of claims, dependent-claim scope, and any specific claim language; the complete written description; and anything regarding prior art, litigation, ownership transfers, or validity.
Generated 10/1/2026, 10:02:02 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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