Yazaki Corporation

Norihito Enomoto

Youichi Arai

Hideaki Kamohara

Tomohiro Kawaguchi

In an apparatus for measuring a pure resistance of an in-vehicle battery, a terminal voltage and a discharging current of the battery are measured when the discharging current flows from the battery. A first approximate equation of a voltage-current characteristic curve is acquired for an increasing discharging current, and a second approximate equation is the voltage-current characteristic curve is acquired for a decreasing discharging current. Two points providing equal synthesized resistances each composed of the pure resistance and polarization resistance component are set on the voltage-current characteristic curves represented by the first and the second approximate equations, respectively. The gradients between the two points in each of the voltage-current characteristic curves are corrected to provide two corrected gradients each exclusive of a voltage drop due to the polarization resistance component. The two corrected gradients are averaged to provide an average value which is measured as a pure resistance of the battery.

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Shizuoka, Japan

Norihito Enomoto