Charger having battery diagnostic function and control method therof

A charger comprising:

• a converter applying one of a perturbation voltage and a perturbation current to a battery;
• and
• a digital signal processor:
• transmitting a perturbation signal in which an alternating current (AC) signal is added to a direct current (DC) signal via the converter,
• measuring an output response of the battery,
• calculating an impedance spectrum according to the output response of the battery,
• calculating an impedance parameter by selecting an equivalent circuit according to the impedance spectrum, and
• estimating a lifespan of the battery by comparing the calculated impedance parameter of the battery with a predetermined impedance parameter of a reference battery,
• wherein the digital signal processor further includes a digital lock-in amplifier which calculates the impedance spectrum according to the output response of the battery, and
• wherein the digital signal processor further includes a parameter extractor selecting an equivalent circuit model of the battery according to the impedance spectrum, and extracting the impedance parameter according to a method of extracting a parameter of the equivalent circuit model.

A method of controlling a charger, the method comprising:

• applying one of a perturbation voltage and a perturbation current to a battery;
• measuring a response output from the battery and calculating an impedance spectrum thereof;
• selecting an equivalent circuit according to the impedance spectrum and extracting an impedance parameter;
• and
• comparing the impedance parameter with a pre-stored impedance parameter of a reference battery and estimating a lifespan of the battery, and
• wherein the applying one of the perturbation voltage and the perturbation current to the battery includes applying the perturbation voltage after charging of the battery is completed, or applying the perturbation current when a charging mode of the battery is switched from a constant current mode to a constant voltage mode.

A method of controlling a charger, the method comprising:

• applying, by a converter, one of a perturbation voltage and a perturbation current to a battery;
• and
• transmitting, by a digital signal processor, a perturbation signal in which an alternating current (AC) signal is added to a direct current (DC) signal via the converter,
• measuring, by the digital signal processor, an output response of the battery,
• calculating, by a digital lock-in amplifier of the digital signal processor, an impedance spectrum according to the output response of the battery,
• calculating, by the digital signal processor, an impedance parameter by selecting an equivalent circuit according to the impedance spectrum, and
• estimating, by the digital signal processor, a lifespan of the battery by comparing the calculated impedance parameter of the battery with a predetermined impedance parameter of a reference battery,
• selecting, by a parameter extractor of the digital signal processor, an equivalent circuit model of the battery according to the impedance spectrum, and
• extracting, by the parameter extractor of the digital signal processor, the impedance parameter according to a method of extracting a parameter of the equivalent circuit model.