Charging method for lithium ion secondary battery and charging control system therefor, and electronic apparatus and battery pack having charging control system

Patent metadata

Field	Value
Publication number	US-10320038-B2
Application number	US-201515533306-A
Country	US
Kind code	B2
Filing date	Dec 10, 2015
Priority date	Dec 25, 2014
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

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 CMAX to CMIN (CMAX/CMIN) is 1.01 to 3.00, where CMAX represents the maximum value of the charging current value and CMIN represents the minimum value of the charging current value.

First claim

The invention claimed is:

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 is reached; 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, I A , I B , and I C satisfy a relationship I A >I B and I B <I C , where I A represents an average charging current value in a range where a state of charge (SOC) of the lithium ion secondary battery is 0%≤SOC<40%, I B represents an average charging current value in a range where the state of charge is 40%≤SOC≤60%, and I C represents an average charging current value in a range where the state of charge is 60%<SOC, and
wherein, in the first step, a ratio of I MAX to I MIN (I MAX /I MIN ) is 1.01 to 3.00, where I MAX represents a maximum value of the charging current value and I 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 I MIN is set in the range where the state of charge is 40%≤SOC≤60%.

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

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.

6. The method according to claim 1 , wherein, in the first step, the minimum value I MIN is set in the range where the state of charge is 40%≤SOC≤60%, and
the maximum value I MAX is 0.4 C to 4.0 C, and the minimum value I MIN is 0.2 C to 2.0 C.

7. The method according to claim 1 , wherein, in the first step, the minimum value I MIN is set in the range where the state of charge is 40%≤SOC≤60%,
the maximum value I MAX is 0.4 C to 4.0 C, and the minimum value I MIN is 0.2 C to 2.0 C, and
a negative electrode of the lithium ion secondary battery includes graphite as a negative electrode active material.

8. The method according to claim 7 , wherein the negative electrode active material includes 40% by mass or more of the graphite.

9. A charging control apparatus for a lithium ion secondary battery, executing:
a first step of charging the lithium ion secondary battery by increasing or decreasing a charging current until a predetermined set voltage is reached, 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, I A , I B , and I C satisfy a relationship I A >I B and I B <I C , where I A represents an average charging current value in a range where a state of charge (SOC) of the lithium ion secondary battery is 0%<SOC<40%, I B represents an average charging current value in a range where the state of charge is 40%≤SOC≤60%, and I C represents an average charging current value in a range where the state of charge is 60%<SOC, and
wherein, in the first step, a ratio of I MAX to I MIN (I MAX /I MIN ) is1.01 to 3.00, where I MAX represents a maximum value of the charging current value and I MIN represents a minimum value of the charging current value.

10. The charging control apparatus according to claim 9 , wherein, in the first step, the minimum value I MIN is set in the range where the state of charge is 40%≤SOC≤60%.

11. The charging control apparatus according to claim 9 , wherein the maximum value I MAX is 0.4 C to 4.0 C, and the minimum value I MIN is 0.2 C to 2.0 C.

12. The charging control apparatus according to claim 9 , wherein, in the first step, the minimum value I MIN is set in the range where the state of charge is 40% ≤SOC≤60%, and
the maximum value I MAX is 0.4 C to 4.0 C, and the minimum value I MIN is 0.2 C to 2.0 C.

13. A battery pack comprising a charging control apparatus for a lithium ion secondary battery,
the charging control apparatus for a lithium ion secondary battery, executing:
a first step of charging the lithium ion secondary battery by increasing or decreasing a charging current until a predetermined set voltage is reached, 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, I A , I B , and I C satisfy a relationship I A >I B and I B <I C , where I A represents an average charging current value in a range where a state of charge (SOC) of the lithium ion secondary battery is 0%≤SOC<40%, I B represents an average charging current value in a range where the state of charge is 40%≤SOC≤60%, and I C represents an average charging current value in a range where the state of charge is 60%<SOC, and
wherein, in the first step, a ratio of I MAX to I MiN (I MAX /I MIN ) is 1.01 to 3.00, where I MAX represents a maximum value of the charging current value and I MIN represents a minimum value of the charging current value.

Assignees

• Maxell Holdings Ltd

Inventors

• Nomura Hirokazu
• Koyama Kunihiko

Classifications

• H02J7/947

  in response to integrated charge or discharge current · CPC title

• H01M10/46

  Accumulators structurally combined with charging apparatus (circuits for charging H02J7/00) · CPC title

• H01M10/0525

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

• H01M10/44 Primary

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

• Y02B40/90

  Cross-Sectional Technologies · mapped topic