Lithium ion secondary battery production method

Patent metadata

Field	Value
Publication number	US-10263288-B2
Application number	US-201515550074-A
Country	US
Kind code	B2
Filing date	Feb 16, 2015
Priority date	Feb 16, 2015
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

A production method is provided for producing a lithium ion secondary battery. The lithium ion secondary battery has an external casing that houses an electrolytic solution and a power generating element. The power generating element includes a positive electrode and a negative electrode layered with a separator. The production method includes first charging the lithium ion secondary battery at a voltage range of 4.0 V or lower and then opening the external casing of the lithium ion secondary battery that has been charged at a range of 4.0 V or lower to discharge gas inside the lithium ion secondary battery to the exterior. Next, the production method further includes re-sealing the external casing and charging the lithium ion secondary battery from which the gas has been discharged until the cell voltage is greater than 4.0 V.

First claim

The invention claimed is:

1. A production method for producing a lithium ion secondary battery formed by sealing a power generation element having a positive electrode and a negative electrode stacked together with a separator and an electrolytic solution inside an external casing, the production method comprising:
Step (1) charging the lithium ion secondary battery at a cell voltage of the lithium ion secondary battery to a first voltage of 2.8 V or less;
Step (2) charging the lithium ion secondary battery to a second voltage of 2.8 V to 4.0 V after a first predetermined time has elapsed after the battery reaches the first voltage;
Step (3) opening the external casing of the lithium ion secondary battery after the battery has been charged to the second voltage to discharge gas inside the lithium ion secondary battery to an exterior, and then re-sealing the external casing; and
Step (4) charging the lithium ion secondary battery from which the gas has been discharged to a third voltage greater than 4.0 V.

2. The production method according to claim 1 , wherein
the lithium ion secondary battery is charged by a constant current-constant voltage charging method in the Steps (1) and (2).

3. The production method according to claim 1 , wherein
the the first predetermined time is one hour or more.

4. The production method according to claim 1 , wherein
a space between an outer circumferential end of the power generating element and an inner circumferential end of the external casing that opposes the outer circumferential end is sealed in the Step (3).

5. The production method according to claim 4 , wherein
the lithium ion secondary battery is roll-pressed from the inner circumferential end of the external casing toward the outer circumferential end of the power generating element in the Step (3).

6. The production method according to claim 4 , wherein
the external casing is formed of a material that can be thermally fused; and
the external casing is resealed by thermally fusing a portion of the external casing positioned between the outer circumferential end of the power generating element and an opening portion of the external casing, the opening portion being formed by the opening of the external casing in the Step (3).

7. The production method according to claim 6 , wherein
the external casing is cut between the portion that is thermally fused and the opening portion, after the external casing is re-sealed, in the Step (3).

8. The production method according to claim 1 , wherein
the discharging the gas is performed in a decompression chamber.

9. The production method according to claim 1 , wherein
the lithium ion secondary battery is charged by a constant current-constant voltage charging method, in the Step (4).

10. The production method according to claim 1 , wherein
the negative electrode of the power generating element contains an aqueous binder.

11. The production method according to claim 10 , wherein
the aqueous binder is a mixture of styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC).

12. The production method according to claim 1 , wherein
the Step (3) of opening the external casing of the lithium ion secondary battery to discharge gas inside the lithium ion secondary battery to the exterior is performed after a second predetermined time has elapsed after the battery reaches the second voltage.

Assignees

• Nissan Motor

Inventors

• Uwai Kenta
• Miyatake Kazuki
• Matsuzaki Ikuma
• Sato Masanobu
• Sasaki Yusuke

Classifications

• H01M10/049

  Processes for forming or storing electrodes in the battery container · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M10/0525

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

• H01M4/362

  Composites · CPC title

• H01M10/058 Primary

  Construction or manufacture · CPC title