Apparatus for managing electricity storage capacity

Abstract

Disclosed is an apparatus for managing electricity storage capacity, which is provided with: an upper limit terminal voltage deriving section, which derives an upper limit terminal voltage when the electricity storage capacity of a capacitor is at the upper limit of the electricity storage capacity; a lower limit terminal voltage deriving section, which derives a lower terminal voltage when the electricity storage capacity of the capacitor is at the lower limit of the electricity storage capacity; a section for calculating a difference between the upper limit voltage and the lower limit voltage, said difference being obtained by reducing the lower limit terminal voltage from the upper limit terminal voltage; an intermediate voltage difference calculating section, which calculates an intermediate voltage difference, i.e., a value obtained by reducing the lower limit terminal voltage of the capacitor from the terminal voltage of the capacitor; a section for calculating the ratio between upper and lower limit voltages, said ratio being the ratio of the intermediate voltage difference to the difference between the upper limit voltage and the lower limit voltage; an intermediate determination voltage ratio deriving section, which derives the intermediate determination voltage ratio corresponding to the upper / lower limit capacities of the capacitor; a voltage ratio comparing section, which compares the ratio between the upper and lower limit voltages with the intermediate determination voltage ratio; and an intermediate electricity storage capacity deriving section, which derives an intermediate electricity storage capacity on the basis of the upper limit electricity storage capacity, the lower limit electricity storage capacity and the intermediate determination voltage ratio when the comparison results obtained from the voltage ratio comparing section satisfy predetermined conditions. Therefore, the electricity storage capacity of the capacitor can be managed with a high accuracy.

Description

technical field [0001] The present invention relates to a storage capacity management device for managing storage capacity of a storage device. Background technique [0002] Vehicles such as EVs (Electric Vehicles) and HEVs (Hybrid Electrical Vehicles: Hybrid Electric Vehicles) are equipped with accumulators that supply power to electric motors and the like. The electric storage unit is provided with a plurality of storage cells connected in series. A secondary battery such as a nickel metal hydride battery or a lithium ion battery is used as the power storage unit. However, in order to use the secondary battery safely, it is necessary to constantly monitor the remaining capacity (SOC: State of Charge) of each power storage unit and perform control to prevent overcharging or overdischarging. [0003] As one of methods of detecting the SOC of an electric storage unit, a method of calculating the SOC based on current accumulation or the like is known. In this method, the ch...

AI Technical Summary

Problems solved by technology

Since this control may shorten the life of the accumulator or adversely affect the durability of the accumulator, this control is not preferred.

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