Mitsubishi Electric Corporation

Hiroto Nishiguchi

Hisatoshi Fukumoto

Hiroyuki Saito

Shingo Yamaguchi

Shigeru Aihara

Satoshi Wachi

Daigo Takemura

Satoshi Hara

Hideaki Tani

Toshihiro Wada

Makiko Kise

Tomoki Takegami

Keisuke Ogasawara

Takahito Ida

A method of estimating a state of charge of a lithium ion battery, which uses a lithium phosphate compound having an olivine-type crystal structure for a positive electrode and uses an active material exhibiting no potential fluctuation due to an insertion/desorption reaction of lithium for a negative electrode, based on a voltage change rate. The method includes: storing a map representing a correspondence relationship between the voltage change rate and the state of charge at a plurality of charging/discharging rates; obtaining a candidate for a present state of charge from an actually measured voltage change rate, by referring to the map; and obtaining the present state of charge through a comparison between the candidate for the state of charge obtained during the charging and the candidate for the state of charge obtained during the discharging.

Charge state estimation method for lithium ion battery and charge state estimation device for lithium ion battery by using correspondence between voltage charge rate and the state of charge of the lithium ion battery

The present invention provides a storage-battery control devicecapable of enhancing economical efficiency by controlling charge state of a storage batteryso that surplus power generated by photovoltaic generation can be entirely charged into the storage batteryeven in a case where power cannot be sold to a system power supply. A storage-battery control deviceaccording to the present invention includes a load-power prediction deviceto predict load power, a PV-power prediction deviceto predict generated power by photovoltaic power generation, and a system controllerto obtain a predicted charge amount that is calculated by subtracting the generated power amount being a summation of the generated power in a prediction segmenthaving a start point set at a predetermined time, from the load power amount being a summation of the load power in the prediction segment, and when the predicted charge amount is positive, to control the charge state of a storage batteryat the start point so that the predicted charge amount can be charged in the prediction segment, wherein an end point of the prediction segmentis a time at which the generated power by photovoltaic power generation is predicted to become equal to the load power after reaching the maximum value of the generated power.

Storage-battery control device, storage-battery charge/discharge system, photovoltaic power generation system, and storage-battery control method

Final state-of-charge calculation means is provided which calculates a final state-of-charge of the battery according to state-of-charge estimate values by electric current integration mode state-of-charge estimation means and equivalent circuit model mode state-of-charge estimation means. The final state-of-charge calculation means performs, when a difference between the state-of-charge estimate value by the electric current integration mode state-of-charge estimation means and the state-of-charge estimate value by the equivalent circuit model mode state-of-charge estimation means becomes less than or equal to the state-of-charge difference threshold value, switching of the final state-of-charge from the state-of-charge estimate value by the electric current integration mode state-of-charge estimation means to the state-of-charge estimate value by the equivalent circuit model mode state-of-charge estimation means.

Battery state-of-charge estimation apparatus and state-of-charge estimation method

A State of Charge (SOC) estimation device is provided for a secondary battery in which a correlation curve indicating a relationship between an SOC and Open Circuit Voltage (OCV) differs between a charging process and discharging process. The SOC estimation device estimates the SOC based on a relational formula in which as measured OCV increases, weights are assigned to the correlation curve for the discharging process, and as the measured OCV decreases, weights are assigned to the correlation curve for the charging process. Thus, the SOC estimation device provides accurate SOC estimates regardless of whether the secondary battery is being used or not.

SOC estimation device for secondary battery

This invention is concerning a device including a current calculator that calculates remaining capacity difference current on the basis of a first remaining battery capacity reflected on open-circuit voltage of a battery and a second remaining battery capacity not reflected on the open-circuit voltage, a first remaining capacity estimator that estimates the first remaining battery capacity on the basis of a value produced by removing the remaining capacity difference current from the current value of the battery and the inter-terminal voltage of the battery, a second remaining capacity calculator that calculates the second remaining battery capacity by adding up the remaining capacity difference current, and an adder that obtains a remaining battery capacity of the battery by adding the estimate of the first remaining battery capacity and the calculation value of the second remaining battery capacity. The current calculator calculates the remaining capacity difference current so that the first remaining battery capacity and the second remaining battery capacity have a prescribed potential difference.

Device and method for estimating remaining battery capacity

Growing community of inventors

Chiyoda-ku, Japan

Hiroto Nishiguchi