Method for producing secondary battery and secondary battery

Patent metadata

Field	Value
Publication number	US-2017025714-A1
Application number	US-201515124802-A
Country	US
Kind code	A1
Filing date	Mar 11, 2015
Priority date	Mar 14, 2014
Publication date	Jan 26, 2017
Grant date	—

Abstract

The present invention provides a method for producing a secondary battery, capable of forming a uniform membrane on a wound body. Provided is a method including a step for reducing an internal pressure of an exterior, a step for pouring an electrolyte solution (E) into the exterior, a step for sealing the exterior, a step for impregnating the electrolyte solution (E) into the wound body from both axial end portions thereof, a step for performing initial charging of a battery, and a step for performing high-temperature aging of the battery. The additive LPFO is added into the electrolyte solution (E) in an amount such that the internal pressure of the exterior in the step for performing the high-temperature aging becomes equal to or higher than a saturation vapor pressure of the electrolyte solution (E) in the high-temperature aging.

First claim

1 . A method for producing a secondary battery, comprising:
a step for reducing an internal pressure of a battery case; a step for pouring an electrolyte solution, into which an additive is added, into the battery case whose internal pressure is reduced; a step for sealing the battery case into which the electrolyte solution is poured; a step for waiting to reduce a difference between a pressure of an external space of a wound body, which is a space between the sealed battery case and the wound body, and a pressure of an internal space of the wound body, and for impregnating the electrolyte solution into the wound body from both axial end portions of the wound body to reduce a volume of the internal space of the wound body; a step for performing initial charging of the secondary battery in which the wound body is impregnated with the electrolyte solution; and a step for performing high-temperature aging of the initially charged secondary battery while maintaining the seal of the battery case, wherein the additive is added into the electrolyte solution in an amount such that, by a gas produced through decomposition reaction of the additive, the internal pressure of the battery case in the step for performing the high-temperature aging becomes equal to or higher than a saturation vapor pressure of the electrolyte solution in the high temperature aging.

2 . The method for producing a secondary battery according to claim 1 , wherein
the additive is added into the electrolyte solution in an amount adjusted so that, by generation of the gas, the internal pressure of the battery case in the step for performing the high-temperature aging becomes equal to or higher than the saturation vapor pressure of the electrolyte solution in the high-temperature aging, and such that, in the step for performing the initial charging, the internal pressure of the battery case becomes lower than the saturation vapor pressure of the electrolyte solution in the high-temperature aging.

3 . The method for producing a secondary battery according to claim 1 , wherein
the additive is added into the electrolyte solution in an amount such that, by generation of the gas, the internal pressure of the battery case immediately after the initial charging becomes equal to an atmospheric pressure.

4 . The method for producing a secondary battery according to claim 1 , wherein
in the step for performing the initial charging, the secondary battery is charged at a lower rate in an electric potential region where the gas is generated than rate in other electric potential regions.

5 . A secondary battery comprising:
a battery case; an electrolyte solution into which an additive is added and which is poured into the battery case whose internal pressure is reduced; and a wound body which is housed in the battery case and in which a volume of an internal space of the wound body is reduced by permeation of the electrolyte solution from both axial end portions of the wound body by leaving the battery case which is sealed after pouring the electrolyte solution into the battery case to stand, wherein high-temperature aging is performed while maintaining the seal of the battery case after initial charging, and the additive is added into the electrolyte solution in an amount such that, by a gas produced through decomposition reaction of the additive, the internal pressure of the battery case in the high-temperature aging becomes equal to or higher than a saturation vapor pressure of the electrolyte solution in the high-temperature aging.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tsukui Akira
• Kado Hiroyasu
• Okayama Shinobu

Classifications

• H01M50/645

  Plugs · CPC title

• H01M50/609

  Arrangements or processes for filling with liquid, e.g. electrolytes · CPC title

• H01M50/627

  Filling ports · CPC title

• H01M10/0431 Primary

  Cells with wound or folded electrodes (H01M10/045 takes precedence) · CPC title

• H01M10/0587

  of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators · CPC title