Uninterruptible power supply system
AssigneeDensei-Lambda Kabushiki Kaisha
InventorHiroshi Nakazawa
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Abstract
There is provided an uninterruptible power supply system capable of preventing life shortening of a lithium-ion secondary battery attributable to its overcharge over the whole period of its use. At the start of use of the lithium-ion secondary battery 22, a charging voltage is set comparatively low. On the other hand, as the lithium-ion secondary battery 22 comes closer to an end of its life, its charging voltage becomes higher. A charging control means 37 variably sets the charging voltage applied to the lithium-ion secondary battery 22 so as to realize a discharge duration thereof may become slightly longer than a backup time required for the system and hence life shortening of the lithium-ion secondary battery 22 attributable to overcharge can be prevented.
Claims13
An uninterruptible power supply system which charges a lithium-ion secondary battery when an input voltage is normal, and discharges the same at the time of voltage reduction or power interruption to thereby supply an electric power to a load, comprising:
- a timing means for counting an elapsed time from the start of use of said lithium-ion secondary battery;
- and
- a charging control means for increasing a charging voltage applied to said lithium-ion secondary battery as said elapsed time increases.
An uninterruptible power supply system which charges a lithium-ion secondary battery when an input voltage is normal, and discharges the same at the time of voltage reduction and power interruption to thereby supply an electric power to a load, comprising:
- a discharge duration obtaining means for discharging the lithium-ion secondary battery and then counting the discharge duration taken for a terminal voltage of the lithium-ion secondary battery to drop to a preset voltage;
- and
- a charging control means for controlling a charging voltage applied to the lithium-ion secondary battery variably so that the discharge duration comes closer to a preset time.
Dependencies are inferred from the claim text.