Method for displaying the 'energy store exhausted' state in electrical devices with electrical energy stores and electrical devices with electrical energy stores for displaying the 'energy store exhausted' state

摘要

Use is made of the characteristic feature that the rise in the "voltage elbow" of a discharging voltage curve (ESK) of the energy store (AKK) is always identical irrespective of the respective condition of the discharging voltage shape to prevent a "low battery" state from being displayed too soon or too late in an item of electrical equipment, e.g. a cordless mobile unit (MTme), with an electrical energy store (AKK), e.g. an accumulator or a battery, for the purpose of optimum use of the energy store which is uniform for different types of energy store and/or the different use conditions of the energy store. During the discharging phase of the energy store, at least one characteristic quantity e.g. the rise or the curve (STG, KRU), is calculated in the form of an actual value (ISW, IKW) giving a characteristic value. Linear regression, for example, is used for calculation. If the actual value (ISW, IKW) exceeds a set value (SSW, SKW) a "low battery" state is reported. Consequently, it is ensured that the accumulator or the mobile unit (MTme) always has approximately the same residual working time irrespective of the type of the energy store and the ambient temperature.