# US 8,541,986 B2 · Charging method and charger for non-aqueous electrolyte secondary battery

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- Number: US 8,541,986 B2
- Document ID: US8541986B2
- Status: Granted
- Kind: B2
- Application number: 13/122,096
- Filed: 2010-06-15
- Published: 2011-11-03
- Granted: 2013-09-24
- Earliest claimed: 2009-09-18
- Assignees: Panasonic Corporation
- Applicants: Tatsuki Hiraoka; Masaya Ugaji; Taisuke Yamamoto; Katsumi Kashiwagi
- Inventors: Tatsuki Hiraoka; Masaya Ugaji; Taisuke Yamamoto; Katsumi Kashiwagi
- Web page: https://patentgrep.com/patent/US8541986B2

## CPC

- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/441: {for several batteries or cells simultaneously or sequentially}
- H02J 7/933: {the cycle being controlled or terminated in response to electric parameters}
- H02J 7/50: acting upon multiple batteries simultaneously or sequentially
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

In a charging method for a non-aqueous electrolyte secondary battery which includes a positive electrode including a lithium-containing composite oxide as an active material, a negative electrode including an alloy-formable negative electrode active material, and a non-aqueous electrolyte, a voltage of the secondary battery is detected. When the detected value is smaller than a predetermined voltage x, charging is performed at a comparatively small current value B. When the detected value is equal to or greater than the predetermined voltage x and smaller than a predetermined voltage z, charging is performed at a comparatively great current value A. When the detected value is equal to or greater than the predetermined voltage z and smaller than a predetermined voltage y, charging is performed at a comparatively small current value C. When the detected value is greater than the predetermined voltage y, constant-voltage charging is performed or charging is terminated. Here, x<z<y.

## Claims

### Claim 1

A charging method for a non-aqueous electrolyte secondary battery which comprises a positive electrode including a lithium-containing composite oxide as an active material, a negative electrode including an alloy-formable negative electrode active material, and a non-aqueous electrolyte, the charging method comprising steps of:
(a) detecting a state of charge of the secondary battery;
(b) comparing the detected state of charge with a predetermined value X, a predetermined value Y, and a predetermined value Z, satisfying Y>Z>X; and
(c) on the basis of the comparison result,
(i) when the detected state of charge is equal to or higher than the predetermined value Y, performing constant-voltage charging or terminating charging,
(ii) when the detected state of charge is equal to or higher than the predetermined value X and lower than the predetermined value Z, performing constant-current charging at a current value A until the detected state of charge reaches a predetermined state of charge,
(iii) when the detected state of charge is lower than the predetermined value X, performing constant-current charging at a current value B, and
(iv) when the detected state of charge is equal to or higher than the predetermined value Z and lower than the predetermined value Y, performing constant-current charging at a current value C satisfying B<C<A.

### Claim 2 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the step of detecting a state of charge includes a step of detecting an open circuit voltage or a closed circuit voltage of the secondary battery.

### Claim 3 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the predetermined value X is a state of charge of 5 to 30%.

### Claim 4 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the predetermined value Z is a state of charge of 65 to 90%.

### Claim 5 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the current value B is 10 to 60% of the current value A.

### Claim 6 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the current value C is 10 to 75% of the current value A.

### Claim 7 (depends on 1)

The charging method for a non-aqueous electrolyte secondary battery in accordance with claim 1, wherein the current value C is greater that the current value B.

### Claim 8

A charger for a non-aqueous electrolyte secondary battery which comprises a positive electrode including a lithium-containing composite oxide as an active material, a negative electrode including an alloy-formable negative electrode active material, and a non-aqueous electrolyte, the charger comprising:
a voltage detection unit for detecting a voltage of the secondary battery;
a state-of-charge detection unit for detecting a state of charge of the secondary battery on the basis of the detected voltage;
a current supply circuit for supplying a current from an external or internal DC power supply to the secondary battery with changing a value of the current stepwise;
a switch for switching an electrically connected state between the secondary battery and the current supply circuit;
a judgment unit for comparing the detected state of charge with a predetermined value X, a predetermined value Y, and a predetermined value Z satisfying Y>Z>X, to make judgment on the detected state of charge; and
a control unit for controlling the switch and the current supply circuit on the basis of the judgment of the judgment unit, in such a manner that
(i) when the detected state of charge is equal to or higher than the predetermined value Y, performing constant-voltage charging or terminating charging,
(ii) when the detected state of charge is equal to or higher than the predetermined value X and lower than the predetermined value Z, performing constant-current charging at a current value A until the detected state of charge reaches a predetermined state of charge,
(iii) when the detected state of charge is lower than the predetermined value X, performing constant-current charging at a current value B, and
(iv) when the detected state of charge is equal to or higher than the predetermined value Z and lower than the predetermined value Y, performing constant-current charging at a current value C satisfying B<C<A.