US 2003/0067282 A1 · Method and unit for computing charging efficiency and charged electrical quantity of battery

Abstract

A charging efficiency, which is a ratio of an electrical quantity charged in a battery as an electromotive force to a total electrical quantity supplied to the battery, is computed at a plurality of measuring points between a start and an end of charging of the battery. A resistance difference of the battery between a resistance at the charge start point and a resistance at one of the measuring points is obtained, and a full charged state resistance is obtained at a full charged state of the battery. By using a ratio of the resistance difference to the full charged state resistance, a charging efficiency of the battery is computed at the one of the measuring points. The battery is in an active state where no passivating film is formed on poles of the battery. A charged electrical quantity of the battery is obtained based on the charging efficiencies sequentially obtained during the charging of the battery when the battery is in the active state. In the mean time, a charged electrical quantity of the battery is obtained based on an integration of a charging current multiplied by a corresponding charging time during a transition period in which a passivating film remains on the poles of the battery before the charging current sufficiently breaks the passivating film.

Claims8

Dependent claims

A method for computing a charging efficiency, which is a ratio of an electrical quantity charged in a battery as an electromotive force to a total electrical quantity supplied to the battery, at any one point in time between a start and an end of charging of the battery, the method comprising:

measuring an initial resistance of the battery at the start of the charging,
measuring a voltage and a current between a pair of terminals of the battery at the one point to obtain an inner resistance of the battery at the one point,
obtaining a resistance difference which is a difference of the inner resistance at the one point and the initial resistance, and
obtaining a ratio of the resistance difference to a full charged state resistance that is a resistance of the battery at a full charged state of the battery,
whereby, a charging efficiency of the battery at the one point is computed based on the ratio.

2 more elements

A unit for computing a charging efficiency, which is a ratio of an electrical quantity charged in a battery as an electromotive force to a total electrical quantity supplied to the battery, at any one point in time between a start and an end of charging of the battery, the unit comprising:

a measuring device for measuring a voltage and a current between a pair of terminals of the battery at the one point to obtain an inner resistance of the battery at the one point,
an initial resistance computing device for obtaining an inner resistance of the battery at the charging start based on a terminal voltage and the corresponding current which are measured by the measuring device,
an on-charging resistance computing device for obtaining an inner resistance of the battery at the one point based on a terminal voltage and a corresponding current which are measured by the measuring device,
a resistance difference computing device for obtaining a difference between of the inner resistance at the one point and the initial resistance,
a storage device for storing an inner resistance at a full charged state of the battery, and
a resistance ratio computing device for obtaining a ratio of the resistance difference to the full charged state resistance,
whereby, a charging efficiency of the battery at the one point is computed based on the ratio.

4 more elements

Dependencies are inferred from the claim text.

Method and unit for computing charging efficiency and charged electrical quantity of battery

Life of this patent

Method and unit for computing charging efficiency and charged electrical quantity of battery

Life of this patent

Abstract

Claims8