Method for manufacturing electrochemical device using pretreatment discharge

Patent metadata

Field	Value
Publication number	US-11233273-B2
Application number	US-201816348372-A
Country	US
Kind code	B2
Filing date	Sep 3, 2018
Priority date	Sep 1, 2017
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

A method for manufacturing an electrochemical device includes a discharge pretreatment step, where, external electric power is applied to a battery to discharge the battery, before charging the battery for the first time to perform formation of the battery, in order to remove a byproduct layer on the surface of a negative electrode. The method including the discharge pretreatment step before the first charge of a battery can improve the cycle life of an electrochemical device.

First claim

What is claimed is:

1. A method for manufacturing an electrochemical device, comprising the steps of:
forming an electrode assembly including a negative electrode, a positive electrode and a separator interposed between the negative electrode and the positive electrode;
introducing the electrode assembly to a battery casing, injecting an electrolyte into the battery casing and sealing the battery casing to obtain a battery;
carrying out pretreatment by applying external electric power to the battery to discharge the battery to provide a pretreated battery; and
charging the pretreated battery for the first time to complete formation of the battery,
wherein the electrolyte comprises an organic solvent and a lithium salt, and
prior to injecting the electrolyte into the battery, determining that the electrolyte satisfies the following Formula 1:
[(Final charge transfer resistance—Initial charge transfer resistance)/Final charge transfer resistance]×100<100%,   [Formula 1]

wherein a charge transfer resistance (CTR) is calculated by injecting the electrolyte to a lithium/lithium symmetric beaker cell obtained by using lithium metal and plotting the values measured by using electrochemical impedance spectroscopy (EIS) as a function of time,
the initial charge transfer resistance is the charge transfer resistance right after injecting the electrolyte to the lithium/lithium symmetric beaker cell, and
the final charge transfer resistance is the charge transfer resistance 18 hours after injecting the electrolyte to the lithium/lithium symmetric beaker cell
wherein the organic solvent of the electrolyte comprises ethylene carbonate and propylene carbonate, and
wherein a volume ratio of ethylene carbonate to propylene carbonate is 30:70-50:50.

2. The method for manufacturing an electrochemical device according to claim 1 , wherein the carrying out pretreatment step is carried out twice or more.

3. The method for manufacturing an electrochemical device according to claim 1 , wherein the carrying out pretreatment step comprises the following steps:
carrying out a first discharge pretreatment;
resting the battery to increase the voltage of the battery; and
carrying out a second discharge pretreatment.

4. The method for manufacturing an electrochemical device according to claim 1 , wherein the negative electrode has a potential of 0-1.0V before the carrying out pretreatment step.

5. The method for manufacturing an electrochemical device according to claim 1 , wherein the positive electrode has a potential of 1.0V or more and the negative electrode has a potential of 0-1.0V at the end of the carrying out pretreatment step.

6. The method for manufacturing an electrochemical device according to claim 1 , which further comprises a step of analyzing a byproduct layer formed during injecting the electrolyte into the battery casing before the carrying out pretreatment step.

7. The method for manufacturing an electrochemical device according to claim 1 , wherein the carrying out pretreatment step is carried out by converting a battery capacity as a function of a thickness of a byproduct layer formed during injecting the electrolyte into the battery casing.

8. The method for manufacturing an electrochemical device according to claim 1 , wherein the negative electrode comprises, as a negative electrode active material, any one of alkali metals, alkaline earth metals, Group 3B metals and transition metals, or combinations thereof.

9. The method for manufacturing an electrochemical device according to claim 8 , wherein the alkali metals include any one of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), or combinations thereof.

10. The method for manufacturing an electrochemical device according to claim 1 , wherein the positive electrode comprises, as a positive electrode active material, any one selected from the group consisting of LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiCoPO 4 , LiFePO 4 , LiNiMnCoO 2 , LiNi 1-x-y-z Co x M1 y M2 z O 2 (wherein each of M1 and M2 independently represents any one selected from the group consisting of Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, each of x, y and z independently represents an atomic proportion of an element forming the oxides, and 0≤x<0.5, 0≤y<0.5, 0≤z<0.5, 0<x+y+z≤1), and mixtures thereof.

11. The method for manufacturing an electrochemical device according to claim 1 , wherein the electrochemical device is a lithium metal battery.

12. The method for manufacturing an electrochemical device according to claim 1 , wherein the lithium salt has a molar concentration of 0.5 M to 1.5 M.

Assignees

• Lg Chemical Ltd

Inventors

• Han Jun-Hyeok
• Ahn Kyoung-Ho
• Park Sol-Ji
• Lee Chul-Haeng

Classifications

• H01M6/50

  Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• H10F71/00

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title

• H10F77/211

  for photovoltaic cells · CPC title

• H10F77/20

  Electrodes · CPC title

• H01M4/04

  Processes of manufacture in general · CPC title