Storage battery control device, power storage system, control method, and computer-readable medium

• US 10,365,334 B2
• Filed: 05/19/2016
• Issued: 07/30/2019
• Est. Priority Date: 05/25/2015
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Miyamoto, Junichi, Kajitani, Hiroshi, Ohtani, Sho
• Primary Examiner(s): Fantu, Yalkew
• Application Number:
  US15/574,518
• Publication Number:
  US 20180128880A1
• Time in Patent Office: 1,167 Days
• Field of Search: 320134
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A storage battery control device includes: a voltage measurement means for measuring terminal voltage of a storage battery; a current measurement means for measuring charge current and discharge current of the storage battery; a capacity calculation means for calculating a cumulative capacity of the storage battery by using the charge current measured by a current measurement unit; a control means for determining an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and a charging/discharging control means for causing the storage battery to operate in accordance with an instruction from the control means, and the charging/discharging control means causes the storage battery to charge by a first charging method from a discharge end voltage to a first charge voltage, to charge by a second charging method at the first charge voltage, to charge by the first charging method from the first charge voltage to a second charge voltage, and to charge by the second charging method at the second charge voltage.

Claims

1. A storage battery control device comprising:

a voltage measurement unit which measures terminal voltage of a storage battery;

a current measurement unit which measures charge current and discharge current of the storage battery;

a capacity calculation unit which calculates a cumulative capacity of the storage battery by using the charge current measured by the current measurement unit;

a control unit which determines an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and

a charging/discharging control unit which causes the storage battery to operate in accordance with an instruction from the control unit, wherein

the charging/discharging control unit causes the storage battery

to charge by a first charging method from a discharge end voltage to a first charge voltage,

to charge by a second charging method at the first charge voltage,

to charge by the first charging method from the first charge voltage to a second charge voltage, and

to charge by the second charging method at the second charge voltage, wherein

the control unit calculates a full charge capacity of the storage battery by using the cumulative capacity measured by the capacity measurement unit,

the control unit calculates a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and

the control unit calculates the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.

2. The storage battery control device according to claim 1, wherein the charging/discharging control unit determines to switch from the second charging method to the first charging method, based on the charge current of the storage battery.

3. The storage battery control device according to claim 1, wherein the control unit

determines to switch from the second charging method to the first charging method, based on a period in which charging is performed by the second charging method.

4. The storage battery control device according to claim 1, wherein the first charge voltage is a voltage corresponding to a capacity higher than a discharge lower-limit capacity set by a user of the storage battery.

5. The storage battery control device according to claim 1, wherein the control unit corrects the full charge capacity in accordance with a charging rate of a storage battery at the discharge end voltage.

6. The storage battery control device according to claim 1, wherein the capacity measurement unit calculates a cumulative capacity obtained until the first charge voltage is reached and a cumulative capacity obtained until the second charge voltage is reached.

7. A power storage system comprising:

a storage battery including a plurality of secondary cells;

a voltage measurement unit which measures voltage of the storage battery;

a current measurement unit which measures charge current and discharge current of the storage battery;

a capacity calculation unit which calculates a cumulative capacity of the storage battery by using the charge current measured by the current measurement unit;

a control unit which determines an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and

a charging/discharging control unit which controls power of the storage battery, based on an instruction from the control unit, wherein

the charging/discharging control unit causes the storage battery

to charge by a first charging method from a discharge end voltage to a first charge voltage,

to charge by a second charging method at the first charge voltage,

to charge by the first charging method from the first charge voltage to a second charge voltage, and

to charge by the second charging method at the second charge voltage, wherein

the control unit calculates a full charge capacity of the storage battery by using the cumulative capacity measured by the capacity measurement unit,

the control unit calculates a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and

the control unit calculates the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.

8. A control method for controlling charging and discharging of a storage battery, comprising:

measuring terminal voltage of the storage battery;

measuring charge current and discharge current of the storage battery;

calculating a cumulative capacity of the storage battery by using the charge current;

determining an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and

controlling power of the storage battery, based on the determined operation of the storage battery, wherein

the control of power of the storage battery includes;

causing to charge by a first charging method from a discharge end voltage to a first charge voltage;

to charge by a second charging method at the first charge voltage;

to charge by the first charging method from the first charge voltage to a second charge voltage; and

to charge by the second charging method at the second charge voltage,

wherein determining an operation of the storage battery comprises;

calculating a full charge capacity of the storage battery by using the cumulative capacity that has been measured,

calculating a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and

calculating the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.