Method and device for regularly monitoring the state of a rechargeable electric energy store, and uninterruptible power supply

Abstract

The invention relates to, inter alia, a method and a device for regularly monitoring the state of a rechargeable electric energy store (500) which can be connected to an electric resistor network (420) via at least two switching elements (410, 411) which are controllable by means of a control device (450). During a monitoring process, current of a first current intensity is drawn from the energy store (500) for a predetermined first time period and an associated first terminal voltage is measured, and subsequently current of a second current intensity is drawn for a predetermined second time period and an associated second terminal voltage is measured. The internal impedance of the electric energy store (500) is determined on the basis of the measured first terminal voltage and second terminal voltage. The state of the electric energy store (500) is then determined on the basis of the determined internal impedance and a provided reference value. The monitoring process is repeated regularly, wherein the electric energy store (500) is kept at a predetermined state of charge between two successive monitoring processes.

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