Degradation determination method for lithium-ion battery, control method for lithium-ion battery, degradation determination apparatus for lithium-ion battery, control apparatus for lithium-ion battery, and vehicle

• US 20100052617A1
• Filed: 09/02/2009
• Published: 03/04/2010
• Est. Priority Date: 09/03/2008
• Status: Abandoned Application

• Current Assignee: DENSO Corporation
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kuroda, Daisuke, Aridome, Koji, Matsumoto, Junichi
• Application Number:
  US12/585,080
• Publication Number:
  US 20100052617A1
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0053 relating to fuel cells
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/25 by controlling the electric load
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• 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 10/48 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: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A degradation state of a lithium-ion battery is determined on the basis of information about a voltage change in the lithium-ion battery obtained in a diagnosis mode in which the lithium-ion battery is successively charged and discharged at a constant power value. The constant power value in the diagnosis mode preferably may vary with the power storage amount and the temperature of the lithium-ion battery. As the information, the degree of a voltage drop in the lithium-ion battery obtained during the discharge can be used.

Claims

1. A degradation determination method for a lithium-ion battery, comprising:

determining a degradation state of the lithium-ion battery based on information about a voltage change in the lithium-ion battery obtained in a diagnosis mode in which the lithium-ion battery is successively charged and discharged at a constant power value.

2. The degradation determination method according to claim 1, wherein the constant power value in the diagnosis mode varies with a power storage amount and a temperature of the lithium-ion battery.

3. The degradation determination method according to claim 1, wherein the information is the degree of a voltage drop in the lithium-ion battery obtained during the discharge.

4. A control method for a lithium-ion battery, comprising:

performing the degradation determination method according to claim 3; and

changing an upper limit value of electric current in lowering direction, when it is determined that the degree of the voltage drop is equal to or more than a threshold value in the degradation determination method, the upper limit value being set as a maximum value of electric current output from the lithium-ion battery.

5. The degradation determination method according to claim 1, wherein the information is the degree of a voltage increase in the lithium-ion battery obtained during the charge.

6. A control method for a lithium-ion battery, comprising:

performing the degradation determination method according to claim 5; and

changing an upper limit value of electric current in lowering direction, when it is determined that the degree of the voltage increase is equal to or more than a threshold value in the degradation determination method, the upper limit value being set as a maximum value of electric current input to the lithium-ion battery.

7. A degradation determination apparatus for a lithium-ion battery, determining a degradation state of the lithium-ion battery, comprising:

an obtaining section which obtains information about a voltage of the lithium-ion battery; and

a determining section which determines the degradation state of the lithium-ion battery based on the information obtained by the obtaining section in a diagnosis mode in which the lithium-ion battery is successively charged and discharged at a constant power value.

8. The degradation determination apparatus according to claim 7, wherein the constant power value in the diagnosis mode varies with a power storage amount and a temperature of the lithium-ion battery.

9. The degradation determination apparatus according to claim 7, wherein the information is the degree of a voltage drop in the lithium-ion battery obtained during the discharge.

10. A control apparatus of a lithium-ion battery, comprising:

the degradation determination apparatus according to claim 9; and

an electric-current control section which, when the determining section determines that the degree of the voltage drop is equal to or more than a threshold value, changes an upper limit value of electric current in lowering direction, the upper limit value being set as a maximum value of electric current output from the lithium-ion battery.

11. The degradation determination apparatus according to claim 7, wherein the information is the degree of a voltage increase in the lithium-ion battery obtained during the charge.

12. A control apparatus of a lithium-ion battery, comprising:

the degradation determination apparatus according to claim 11; and

an electric-current control section which, when the determining section determines that the degree of the voltage increase is equal to or more than a threshold value, changes an upper limit value of electric current in lowering direction, the upper limit value being set as a maximum value of electric current input to the lithium-ion battery.

13. A vehicle comprising:

the control apparatus according to claim 10 mounted on the vehicle; and

the lithium-ion battery.

14. A vehicle comprising:

the control apparatus according to claim 12 mounted on the vehicle; and

the lithium-ion battery.