CHARGING METHOD FOR LITHIUM ION SECONDARY BATTERY AND CHARGING CONTROL SYSTEM THEREFOR, AND ELECTRONIC APPARATUS AND BATTERY PACK HAVING CHARGING CONTROL SYSTEM

• US 20180013179A1
• Filed: 12/10/2015
• Published: 01/11/2018
• Est. Priority Date: 12/25/2014
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi Maxell Limited (Maxell, Ltd.)
• Inventors: NOMURA, Hirokazu, KOYAMA, Kunihiko
• Granted Patent: US 10,320,038 B2
• Time in Patent Office: Days
• 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 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H02J 7/00716 in response to integrated charge or discharge current
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for charging a lithium ion secondary battery of the present invention includes a first step and a second step. In the first step, A, B, and C satisfy the relationship A>B and B<C, where A represents an average charging current value in the range where a charge rate of the lithium ion secondary battery is 0% or more and less than 40%, B represents an average charging current value in the range where the charge rate is 40% or more and 60% or less, and C represents an average charging current value in the range where the charge rate is more than 60%. In the first step, the ratio of C_MAX to C_MIN (C_MAX/C_MIN) is 1.01 to 3.00, where C_MAX represents the maximum value of the charging current value and C_MIN represents the minimum value of the charging current value.

Claims

1. A method for charging a lithium ion secondary battery comprising:

a first step of charging the lithium ion secondary battery by increasing or decreasing a charging current until a predetermined set voltage; and

a second step of charging the lithium ion secondary battery that has reached the set voltage with a constant voltage while decreasing the charging current to maintain the set voltage,

wherein, in the first step, A, B, and C satisfy a relationship A>

B and B<

C, where A represents an average charging current value in a range where a charge rate of the lithium ion secondary battery is 0% or more and less than 40%, B represents an average charging current value in a range where the charge rate is 40% or more and 60% or less, and C represents an average charging current value in a range where the charge rate is more than 60%, and

wherein, in the first step, a ratio of C_MAX to C_MIN (C_MAX/C_MIN) is 1.01 to 3.00, where C_MAX represents a maximum value of the charging current value and C_MIN represents a minimum value of the charging current value.

2. The method according to claim 1, wherein, in the first step, the minimum value C_MIN is set in the range where the charge rate is 40% or more and 60% or less.

3. The method according to claim 1, wherein the maximum value C_MAX is 0.4C to 4.0C, and the minimum value C_MIN is 0.2C to 2.0C.

4. The method according to claim 1, wherein a negative electrode of the lithium ion secondary battery includes graphite as a negative electrode active material.

5. The method according to claim 4, wherein the negative electrode active material includes 40% by mass or more of the graphite.

11. The method according to claim 1, wherein, in the first step, the minimum value C_MIN is set in the range where the charge rate is 40% or more and 60% or less, and

the maximum value C_MAX is 0.4C to 4.0C, and the minimum value C_MIN is 0.2C to 2.0C.

12. The method according to claim 1, wherein, in the first step, the minimum value C_MIN is set in the range where the charge rate is 40% or more and 60% or less,

the maximum value C_MAX is 0.4C to 4.0C, and the minimum value C_MIN is 0.2C to 2.0C, and

a negative electrode of the lithium ion secondary battery includes graphite as a negative electrode active material.

13. The method according to claim 12, wherein the negative electrode active material includes 40% by mass or more of the graphite.

6. A charging control system for a lithium ion secondary battery comprising:

a charging algorithm that includes a first step of charging the lithium ion secondary battery by increasing or decreasing a charging current until a predetermined set voltage, and a second step of charging the lithium ion secondary battery that has reached the set voltage with a constant voltage while decreasing the charging current to maintain the set voltage,

wherein, in the first step, A, B, and C satisfy a relationship A>

B and B<

C, where A represents an average charging current value in a range where a charge rate of the lithium ion secondary battery is 0% or more and less than 40%, B represents an average charging current value in a range where the charge rate is 40% or more and 60% or less, and C represents an average charging current value in a range where the charge rate is more than 60%, and

wherein, in the first step, a ratio of C_MAX to C_MIN (C_MAX/C_MIN) is 1.01 to 3.00, where C_MAX represents a maximum value of the charging current value and C_MIN represents a minimum value of the charging current value.

7. The charging control system according to claim 6, wherein, in the first step, the minimum value C_MIN is set in the range where the charge rate is 40% or more and 60% or less.

8. The charging control system according to claim 6, wherein the maximum value C_MAX is 0.4C to 4.0C, and the minimum value C_MIN is 0.2C to 2.0C.

14. The charging control system according to claim 6, wherein, in the first step, the minimum value C_MIN is set in the range where the charge rate is 40% or more and 60% or less, and

the maximum value C_MAX is 0.4C to 4.0C, and the minimum value C_MIN is 0.2C to 2.0C.

9. (canceled)

10. A battery pack comprising a charging control system for a lithium ion secondary battery,

the charging control system for a lithium ion secondary battery comprising:

a charging algorithm that includes a first step of charging the lithium ion secondary battery by increasing or decreasing a charging current until a predetermined set voltage, and a second step of charging the lithium ion secondary battery that has reached the set voltage with a constant voltage while decreasing the charging current to maintain the set voltage,

wherein, in the first step, A, B, and C satisfy a relationship A>

B and B<

C, where A represents an average charging current value in a range where a charge rate of the lithium ion secondary battery is 0% or more and less than 40%, B represents an average charging current value in a range where the charge rate is 40% or more and 60% or less, and C represents an average charging current value in a range where the charge rate is more than 60%, and

wherein, in the first step, a ratio of C_MAX to C_MIN (C_MAX/C_MIN) is 1.01 to 3.00, where C_MAX represents a maximum value of the charging current value and C_MIN represents a minimum value of the charging current value.