Method of preparing lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2018205090-A1
Application number	US-201715743749-A
Country	US
Kind code	A1
Filing date	Mar 30, 2017
Priority date	Mar 30, 2016
Publication date	Jul 19, 2018
Grant date	—

Abstract

The present invention relates to a method of preparing a lithium secondary battery which may improve productivity and performance of the lithium secondary battery by visually measuring an electrolyte solution impregnation time for an electrode active material, setting an optimum estimated electrolyte solution impregnation time of the electrolyte solution for a battery based on a measured result, and reflecting the optimum estimated electrolyte solution impregnation time in a production process.

First claim

1 . A method of preparing a lithium secondary battery, the method comprising steps of:
forming an electrode material mixture layer having a thickness of 10 μm to 200 μm, a porosity of 18 vol % to 30 vol %, and a density of 1 g/cc to 4.5 g/cc by coating a perforated foil with an electrode active material slurry and rolling the coated foil (S1); preparing a non-aqueous electrolyte solution (S2); calculating an electrolyte solution impregnation rate by measuring a time at which the non-aqueous electrolyte solution passes through the electrode material mixture layer (S3); and setting an estimated electrolyte solution impregnation time of a measurement target full cell by using the electrolyte solution impregnation rate (S4).

2 . The method of claim 1 , wherein the perforated foil is formed of a material selected from the group consisting of copper, aluminum, iron, tin, titanium, nickel, lead, zinc, silver, gold, stainless steel, and a combination thereof.

3 . The method of claim 1 , wherein a hole diameter of the perforated metal foil is in a range of 0.1 μm to 1 mm.

4 . The method of claim 1 , wherein a hole diameter of the perforated metal foil is in a range of 10 μm to 1 mm.

5 . The method of claim 1 , wherein the electrode active material slurry comprises an electrode active material; a solvent; and at least one additive of a binder, a conductive agent, and a filler.

6 . The method of claim 5 , wherein the electrode active material is a negative electrode active material or a positive electrode active material.

7 . The method of claim 6 , wherein, in a case in which the electrode active material slurry comprises the negative electrode active material,
the electrode material mixture layer has a porosity of 20 vol % to 30 vol % and a density of 1.3 g/cc to 1.8 g/cc.

8 . The method of claim 6 , wherein, in a case in which the electrode active material slurry comprises the positive electrode active material,
the electrode material mixture layer has a porosity of 18 vol % to 30 vol % and a density of 3.4 g/cc to 4.2 g/cc.

9 . The method of claim 1 , wherein the electrode active material slurry is pressure-molded at a pressure of 10 MPa to 100 MPa in a temperature range of 0° C. to 120° C.

10 . The method of claim 1 , wherein the step S3 of calculating the electrolyte solution impregnation rate comprises:
dispensing 1 μL to 10 μL of the non-aqueous electrolyte solution on a top surface of the electrode material mixture layer, and calculating the electrolyte solution impregnation rate by measuring an electrolyte solution passing time from a time of dispensing the non-aqueous electrolyte solution until a time at which the dispensed non-aqueous electrolyte solution passes through the electrode material mixture layer and appears on a bottom surface.

11 . The method of claim 10 , wherein a method of measuring the electrolyte solution passing time is performed by visual confirmation or is performed by indirect confirmation through a medium between an object and an observer.

12 . The method of claim 1 , wherein the electrolyte solution impregnation rate is calculated using Equation 1:
Impregnation rate (μm/sec)=electrode material mixture layer thickness (μm)/time (sec) from a time of dispensing the electrolyte solution to a time of reaching a bottom surface.   [Equation 1]

13 . The method of claim 1 , wherein the estimated electrolyte solution impregnation time of the measurement target full cell is set by using Equation 2:

Estimated



full



cell



impregnation



time




(
hr
)

=

0.0086


(

mm
2

)

×
electrode



thickness




(
μm
)

×

(

electrode



area




(

mm
2

)

)

2

electrolyte



solution



impregnation



rate


Assignees

• Lg Chemical Ltd

Inventors

• Lee Jung Pil
• Lee Sang Kyun

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/742

  perforated material · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M10/058

  Construction or manufacture · CPC title