Battery full charge capacity detection method

Abstract

In a fully-charged battery capacity detection method, first and second no-load voltages (VOCV1, VOCV2) of a battery are detected at first no-load timing and second no-load timing, respectively. First and second remaining capacities (SOC1 [%], SOC2 [%]) of the battery are determined based on the first and second no-load voltages, respectively, if the first no-load voltage (VOCV1) falls within a predetermined voltage range. A fully-charged capacity (Ahf) of the battery is calculated based on a remaining capacity variation rate ( w S [%]) and a capacity variation value ( w Ah) of the battery. The variation rate of the remaining capacity is calculated based on the difference between the first and second remaining capacities.; The capacity variation value of the battery is calculated based the integrated value of the charging current and discharge currents of the battery to be charged / discharged from the first no-load timing to the second no-load timing.

Description

Technical field [0001] The present invention relates to a method of correcting the full charge capacity of a battery that becomes smaller with charging and discharging, and simultaneously detecting accurately. Background technique [0002] As the battery is repeatedly charged and discharged, the capacity that can be fully charged, that is, the full charge capacity Ahf, decreases over time. The full charge capacity Ahf is represented by the product of current A and time h. The full charge capacity Ahf is the capacity that can be discharged until a fully charged battery is completely discharged. If a fully charged battery is discharged, the product of the current A that can be discharged and the time h decreases. That is, the remaining capacity Ahr becomes smaller than the full charge capacity Ahf. The remaining capacity Ahr relative to the full charge capacity Ahf is expressed as the remaining capacity SOC [%]. The battery’s residual capacity SOC[%] can be determined by the batter...

AI Technical Summary

Problems solved by technology

However, this method estimates the degree of decrease in the full charge capacity from the accumulated value of the charge capacity or storage temperature and remaining capacity, so it is difficult to always accurately detect the full charge capacity of the battery

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