Analysis method for crack rate of electrode active material of electrode for lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2021012483-A1
Application number	US-202016922490-A
Country	US
Kind code	A1
Filing date	Jul 7, 2020
Priority date	Jul 10, 2019
Publication date	Jan 14, 2021
Grant date	—

Abstract

Provided is an analysis method for a crack rate of an electrode active material of an electrode, comprising the steps of: forming an electrode including an electrode active material, a binder, and a conductive material; impregnating the electrode with a resin and visualizing material regions including the electrode active material, the binder, and the conductive material which are included in the electrode, and a pore region; cutting the electrode and forming an electrode cross-section sample; photographing a cross section of the electrode cross-section sample using a scanning electron microscope and obtaining a cross-sectional image; performing primary image processing on the cross-sectional image and extracting total surface area pixels of the electrode active material; performing secondary image processing on the cross-sectional image and extracting total boundary pixels of the electrode active material; and calculating a crack rate of the electrode active material of the electrode in the cross-sectional image.

First claim

1 . An analysis method for a crack rate of an electrode active material of an electrode for a secondary battery, comprising the steps of:
forming an electrode including an electrode active material, a binder, and a conductive material; impregnating the electrode with a resin and visualizing material regions including the electrode active material, the binder, and the conductive material which are included in the electrode, and a pore region; cutting the electrode and forming an electrode cross-section sample; photographing a cross section of the electrode cross-section sample using a scanning electron microscope and obtaining a cross-sectional image; performing primary image processing on the cross-sectional image and extracting total surface area pixels of the electrode active material; performing secondary image processing on the cross-sectional image and extracting total boundary pixels of the electrode active material; and calculating a crack rate of the electrode active material of the electrode in the cross-sectional image using Equation 1,
A crack rate (%) of an electrode active material={(total surface area pixels of the electrode active material which are extracted from a cross-sectional image/total boundary pixels of the electrode active material which are extracted from the cross-sectional image)×100}.  [Equation 1]

2 . The analysis method of claim 1 , further comprising step of pressing the electrode and calculating a crack rate of the pressed electrode active material of the electrode in the cross-sectional image using Equation 1.

3 . The analysis method of claim 1 , wherein the resin includes an epoxy-based resin.

4 . The analysis method of claim 1 , wherein the cutting of the electrode in the is performed by irradiating the electrode with an argon ion beam of an ion milling device.

5 . The analysis method of claim 4 , wherein an ion beam current of the ion milling device ranges from 10 μA to 250 μA.

6 . An analysis method for a crack rate of an electrode active material of an electrode for a secondary battery, comprising the steps of:
forming an electrode including an electrode active material, a binder, and a conductive material; impregnating the electrode with a resin and visualizing material regions including the electrode active material, the binder, and the conductive material which are included in the electrode, and a pore region; cutting the electrode and forming an electrode cross-section sample; photographing a cross section of the electrode cross-section sample using a scanning electron microscope and obtaining a cross-sectional image; performing primary image processing on the cross-sectional image and extracting total surface area pixels of the electrode active material; performing secondary image processing on the cross-sectional image and extracting total boundary pixels of the electrode active material; calculating a crack rate of the electrode active material of the electrode in the cross-sectional image using Equation 1 below,
A crack rate (%) of an electrode active material={(total surface area pixels of the electrode active material which are extracted from a cross-sectional image/total boundary pixels of the electrode active material which are extracted from the cross-sectional image)×100};  [Equation 1]

manufacturing a secondary battery including the electrode; and charging or discharging the secondary battery with a driving voltage of 3.0 to 4.2 V and then separating the electrode from the secondary battery, and calculating the crack rate of the electrode active material of the separated electrode according to Equation 1.

Assignees

• Lg Chemical Ltd

Inventors

• Han Jung Hoon
• Baek Joo Yul

Classifications

• G01N23/2251 Primary

  using incident electron beams, e.g. scanning electron microscopy [SEM] · CPC title

• G01N1/04

  in the solid state, e.g. by cutting · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/0447

  of complete cells or cells stacks · CPC title