Method of Activating a Lithium Secondary Battery Including a Positive Electrode Additive

Patent metadata

Field	Value
Publication number	US-2024204270-A1
Application number	US-202217925654-A
Country	US
Kind code	A1
Filing date	Apr 19, 2022
Priority date	Jun 2, 2021
Publication date	Jun 20, 2024
Grant date	—

Abstract

A method of activating a lithium secondary battery and a lithium secondary battery prepared by the same are disclosed herein. In some embodiments, a method includes charging the lithium secondary battery to a state of charge (SOC) of 90% or more in an activation step, wherein the lithium secondary battery having an electrode assembly comprising a positive electrode and an electrolyte, wherein the positive electrode comprises a mixture layer having a positive electrode active material and a positive electrode additive, and degassing the lithium secondary battery during the activation step to removing gas inside the secondary battery. The method is advantageous in that a side reaction gas can be removed by performing degassing during activation, thereby forming a stable SEI film on the electrode surface to improve battery performance and battery safety.

First claim

1 . A method of activating a lithium secondary battery, comprising:
charging the lithium secondary battery to a state of charge (SOC) of 90% or more in an activation step, wherein the lithium secondary battery having an electrode assembly comprising a positive electrode and an electrolyte, wherein the positive electrode comprises a mixture layer having a positive electrode active material and a positive electrode additive; and degassing the lithium secondary battery during the activation step to removing gas inside the secondary battery.

2 . The method of claim 1 ,
wherein the activation step comprises two or more activation steps, and wherein the degassing process is performed between each of the two or more activation steps.

3 . The method of claim 1 , wherein the degassing performed two or more times during the activation step.

4 . The method of claim 1 ,
wherein the activation step further comprises: a first activation step wherein charging is performed at a rate of 0.5 C or less up to a first level of SOC; and a second activation step wherein charging is performed at a rate of greater than 0.5 C up to a second level of SOC, wherein the second level of SOC is greater than the first level of SOC.

5 . The method of claim 1 ,
wherein the activation step further comprises: a first activation step wherein the lithium secondary battery is charged to an SOC of 20% or less; a second activation step wherein the lithium secondary battery is charged from an SOC greater than 20% to 40% or less; a third activation step wherein the lithium secondary battery is charged from an SOC greater than 40% to 70% or less; and a fourth activation step wherein the lithium secondary battery is charged to an SOC of 90% or more, wherein the degassing is performed between at least one of the first and second activation steps, the second and third activation steps, or the third and fourth activation steps.

6 . The method of claim 5 , wherein the degassing performed between the first and second activation steps, the second and third activation steps, and the third and fourth activation steps.

7 . The method of claim 5 , wherein
during the first activation step, charging of the lithium secondary battery is performed at a rate of 0.5 C or less, and wherein, during the second to fourth activation steps, charging of the lithium secondary battery is performed at a rate of more than 0.5 C.

8 . The method of claim 1 , wherein the activation step further comprises:
pressurizing the lithium secondary battery.

9 . The method of claim 1 , wherein the activation step is performed at a temperature of 40° C. to 70° C.

10 . The method of claim 1 , wherein the positive electrode additive is a lithium cobalt oxide represented by the following Chemical Formula 1:
Li p Co (1−q) M 1 q O 4   [Chemical Formula 1]
wherein, M 1 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, 5≤p≤7; and 0≤q≤0.5.

11 . The method of claim 10 , wherein, in Chemical Formula 1, M 1 is Zn, and 0.2≤q≤0.4.

12 . The method of claim 1 , wherein the content of the positive electrode additive is 0.1 to 5 wt % based on the total weight of the mixture layer.

13 . The method of claim 1 , further comprising:
aging the lithium secondary battery at a temperature of 40° C. to 80° C. after the activation step.

14 . A lithium secondary battery including an electrode assembly including:
a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an electrolyte, wherein the positive electrode comprises a positive electrode current collector and a positive electrode mixture layer, wherein the positive electrode mixture layer comprises a positive electrode active material, a positive electrode additive represented by the following Chemical Formula 1, a conductive material, and a binder, and wherein the positive electrode active material is a lithium nickel composite oxide represented by the following Chemical Formula 2:
Li p Co (1−q) M 1 q O 4   [Chemical Formula 1]

Li x [Ni y Co z Mn w M 2 v ]O u   [Chemical Formula 2]

wherein, M 1 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, 5≤p≤7, 0≤q≤0.5, M 2 is at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, 1.0≤x≤1.30, 0.1≤y<0.95, 0.01<z≤0.5, 0.01<w≤0.5, 0≤v≤0.2, and 1.5≤u≤4.5.

15 . The battery of claim 14 ,
wherein the negative electrode comprises a negative electrode current collector and a negative electrode mixture layer positioned on the negative electrode current collector, wherein the negative electrode mixture layer contains a negative electrode active material, and wherein the negative electrode active material contains a carbon material and a silicon material.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Shul Kee
• Oh Sang Seung
• Kim Hye Hyeon
• Jo Chi Ho

Classifications

• H01M4/364

  as mixtures · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M10/0525

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

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title