Lithium-Ion Secondary Battery System

• US 20110193529A1
• Filed: 02/08/2011
• Published: 08/11/2011
• Est. Priority Date: 02/09/2010
• Status: Active Grant

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Vehicle Energy, Ltd. (Hitachi, Ltd.)
• Inventors: NISHIMURA, Etsuko, NISHIMURA, Katsunori, TANAKA, Akihide
• Granted Patent: US 8,604,755 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• 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: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A lithium-ion secondary battery system is provided which can improve the cycle life and the storage property of a lithium-ion secondary battery and can decrease a discharge capacity which cannot be recharged. The lithium-ion secondary battery system includes a lithium-ion secondary battery having a cathode, an anode including carbon, and a non-aqueous electrolyte; a charge/discharge circuit for putting the lithium-ion secondary battery on charge according to a charge control parameter; and an arithmetic processing section for controlling the charge/discharge circuit. The arithmetic processing section obtains battery characteristics of the lithium-ion secondary battery, changes a value of the charge control parameter when the arithmetic processing section determines that the battery characteristics satisfies a condition for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished.

Claims

1. A lithium-ion secondary battery system comprising:

a lithium-ion secondary battery having a cathode, an anode including carbon, and a non-aqueous electrolyte;

a charge/discharge circuit for putting the lithium-ion secondary battery on charge according to a charge control parameter; and

an arithmetic processing section for controlling the charge/discharge circuit,

wherein the arithmetic processing section obtains battery characteristics of the lithium-ion secondary battery, changes a value of the charge control parameter when the arithmetic processing section determines that the battery characteristics satisfies a condition for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished.

2. The lithium-ion secondary battery system according to claim 1,

wherein the arithmetic processing section obtains an integrated value of the discharge capacity and a ratio of an amount of voltage change and a discharge capacity as the battery characteristics, changes the value of the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished.

3. The lithium-ion secondary battery system according to claim 2,

wherein the arithmetic processing section increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

4. The lithium-ion secondary battery system according to claim 1,

wherein the arithmetic processing section obtains an integrated value of the discharge capacity and a ratio of an amount of temperature change in time and a discharge capacity as the battery characteristics, increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

5. The lithium-ion secondary battery system according to claim 1,

wherein the arithmetic processing section obtains an integrated value of the discharge capacity and a ratio of a width of voltage change and a width of initial voltage change as the battery characteristics, increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

6. The lithium-ion secondary battery system according to claim 1,

wherein the arithmetic processing section is detachable.

7. The lithium-ion secondary battery system according to claim 1,

wherein the anode includes a mixture of graphite and non-graphite carbon as an anode active material, and

the cathode and the anode have different ratios of an amount of voltage change and a discharge capacity from each other.

8. The lithium-ion secondary battery system according to claim 7,

wherein a charge capacity density per unit weight of the anode active material is 250 to 330 mAh/g when the lithium-ion secondary battery is charged to a rated capacity.