Charge/discharge control method and charge/discharge control apparatus for lithium ion battery

Patent metadata

Field	Value
Publication number	US-9935477-B2
Application number	US-201314909278-A
Country	US
Kind code	B2
Filing date	Aug 22, 2013
Priority date	Aug 22, 2013
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

In a charge/discharge control method of a lithium ion battery having a negative electrode active material and connected to a charge/discharge control device, battery information regarding a charge/discharge state of the lithium ion battery is acquired by the charge/discharge control device, a degradation state of the lithium ion battery is determined on the basis of the battery information, by the charge/discharge control device, and a voltage range for charge/discharge of the lithium ion battery is changed on the basis of a determination result of the degradation state, by the charge/discharge control device.

First claim

The invention claimed is:

1. A charge/discharge control method for a lithium ion battery having a negative electrode active material, the lithium ion battery being connected to a charge/discharge control device, the method comprising:
acquiring battery information regarding a charge/discharge state of the lithium ion battery by the charge/discharge control device;
calculating a Q-dV/dQ curve showing a relationship of discharge capacity Q of the lithium ion battery and dV/dQ, which shows a ratio of a change amount dV of a battery voltage V to a change amount dQ of the discharge capacity Q on the basis of the battery information, by the charge/discharge control device;
determining a degradation state of the lithium ion battery on the basis of the information-dV/dQ curve, by the charge/discharge control device; and
changing a voltage range for charge/discharge of the lithium ion battery on the basis of a determination result of the degradation state, by the charge/discharge control device;
wherein SOC recalculation to recalculate a relationship of the discharge capacity Q of the lithium ion battery and a state of charge SOC of the lithium ion battery is executed on the basis of the determination result of the degradation state, by the charge/discharge control device, and the voltage range is changed on the basis of a result of the SOC recalculation, by the charge/discharge control device.

2. A charge/discharge control device for controlling charge/discharge of a lithium ion battery having a negative electrode active material, comprising:
a battery information acquisition unit which acquires battery information regarding a charge/discharge state of the lithium ion battery;
a degradation state determination unit which determines a degradation state of the lithium ion battery, on the basis of the battery information acquired by the battery information acquisition unit; and
a voltage range change unit which changes a voltage range for charge/discharge of the lithium ion battery, on the basis of a determination result of the degradation state by the degradation state determination unit
wherein the degradation state determination unit calculates a Q-dV/dQ curve showing a relationship of discharge capacity Q of the lithium ion battery and dV/dQ, which shows a ratio of a change amount dV of a battery voltage V to a change amount dQ of the discharge capacity Q, on the basis of the battery information, and determines the degradation state of the lithium ion battery, on the basis of the Q-dV/dQ curve; and
wherein the voltage range change unit executes SOC recalculation to recalculate a relation of the discharge capacity Q of the lithium ion battery and a state of charge SOC of the lithium ion battery, on the basis of the determination result of the degradation state, and changes the voltage range, on the basis of a result of the SOC recalculation.

Assignees

• Hitachi Ltd

Inventors

• Araki Chieko
• Takahashi Hirofumi
• Yonemoto Masahiro

Classifications

• H01M10/48

  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 title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• G01R31/3606

  Physics · mapped topic

• H02J7/007 Primary

  Electricity · mapped topic

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title