ELECTROCHEMICAL DEVICE

• US 20140239905A1
• Filed: 02/24/2014
• Published: 08/28/2014
• Est. Priority Date: 02/28/2013
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei
• Application Number:
  US14/187,562
• Publication Number:
  US 20140239905A1
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H01M 10/054 Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Deterioration of a battery is prevented or the degree of deterioration of a battery is reduced, and charge and discharge performance of the battery is maximized and the charge and discharge performance of the battery is maintained for a long time. In a battery such as a sodium-ion secondary battery, various malfunctions or deterioration is caused by a reaction product deposited on an electrode surface. The reaction product is dissolved by applying a signal (inversion pulse current) to make a current flow in a direction opposite to a direction in which the reaction product is formed more than once in charging or discharging.

Claims

1. A method for charging or discharging a sodium-ion secondary battery comprising the steps of:

supplying a first current between a first electrode and a second electrode in a first direction; and

supplying a second current between the first electrode and the second electrode in a direction opposite to the first direction,

wherein charge or discharge is performed by alternately supplying the first current and the second current, and

wherein one period in which the second current is supplied is shorter than one period in which the first current is supplied.

2. The method according to claim 1,

wherein a reaction product is deposited on a surface of the first electrode or the second electrode by supplying the first current, and

wherein the reaction product is dissolved by supplying the second current.

3. The method according to claim 2,

wherein the reaction product is sodium metal.

4. The method according to claim 1,

wherein the period in which the second current is supplied is longer than or equal to 0.1 seconds and shorter than or equal to 3 minutes.

5. The method according to claim 1,

wherein an amount of the second current is 2 times to 10 times greater than an amount of the first current.

6. The method according to claim 1,

wherein the sodium-ion secondary battery is included in an electrical device.

7. A method for maintaining a battery, the battery comprising:

a first electrode; and

a second electrode,

wherein the first electrode or the second electrode comprises sodium,

the method comprising;

supplying a first current between the first electrode and the second electrode in a first direction; and

supplying a second current between the first electrode and the second electrode in a direction opposite to the first direction,

wherein charge or discharge is performed by alternately supplying the first current and the second current, and

wherein one period in which the second current is supplied is shorter than one period in which the first current is supplied.

8. The method according to claim 7,

wherein a reaction product is deposited on a surface of the first electrode or the second electrode by supplying the first current, and

wherein the reaction product is dissolved by supplying the second current.

9. The method according to claim 8,

wherein the reaction product is sodium metal.

10. The method according to claim 7,

wherein the period in which the second current is supplied is longer than or equal to 0.1 seconds and shorter than or equal to 3 minutes.

11. The method according to claim 7,

wherein an amount of the second current is 2 times to 10 times greater than an amount of the first current.

12. The method according to claim 7,

wherein the battery is in a power storage device stored in an underfloor space of a building.

13. A sodium-ion secondary battery comprising:

a positive electrode; and

a negative electrode,

wherein a sodium deposit does not substantially exist on a surface of the negative electrode after charge and discharge.

14. The sodium-ion secondary battery according to claim 13,

wherein the sodium-ion secondary battery is in a power storage device stored in an underfloor space of a building.