Lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-10170760-B2
Application number	US-201514941118-A
Country	US
Kind code	B2
Filing date	Nov 13, 2015
Priority date	Nov 14, 2014
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

The present invention relates to a secondary battery, specifically, a secondary battery having excellent stability and improved output characteristic and low temperature characteristic by including a cathode active material in which at least one of metals forming the cathode active material has a concentration gradient in an entire region from a central portion up to a surface portion; and a conductive material mixture in which carbon nanotube is mixed with carbon black at an appropriate ratio, the carbon black being a spherical nanoparticle.

First claim

What is claimed is:

1. A secondary battery comprising:
A cathode active material in which at least one of metals forming the cathode active material has a concentration gradient in an entire region from a central portion up to a surface portion;
a conductive material mixture in which carbon nanotube is mixed with carbon black; and wherein the carbon black and the carbon nanotube are mixed at a mixing ratio of 10:1 to 6:4,
wherein the cathode active material is represented by Chemical Formula 1 below, and in Chemical Formula 1, at least one of M1, M2, and M3 has a continuous concentration gradient from the central portion up to the surface portion:
Li x M1 a M2 h M3 c O v   Chemical Formula 1

wherein in Chemical Formula 1,
M1 is Ni, M2 is Mn, and M3 is Co, and
0<x<1.1, 2<y<2.02, 0<a<l, 0<b<1, 0<c<1, 0<a+b+c<1;
wherein any one of M1, M2, and M3 has a predetermined concentration from the central portion up to the surface portion, and another one has a concentration gradient region in which a concentration is increased from the central portion up to the surface portion, and the other one has a concentration gradient region in which a concentration is decreased from the central portion up to the surface portion,
wherein the central portion of the particle means a portion within a radius of 0.1 to 0.2 μm from the center of the active material particle, and the surface portion of the particle means a portion within a radius of 0.1 to 0.2 μm from the outermost of the particle.

2. The secondary battery of claim 1 , wherein the carbon black is a spherical nanoparticle.

3. The secondary battery of claim 1 , wherein M1 is Ni, and 0.6≤a≤0.95 and 0.05≤b+c≤0.4 are satisfied.

4. The secondary battery of claim 1 , wherein M1 is Ni, and 0.7≤a≤0.9 and 0.1≤b+c≤0.3 are satisfied.

5. The secondary battery of claim 1 , wherein the conductive material mixture has a content of 2 to 8 wt % relative to 100 wt % of the cathode active material.

Assignees

• Sk Innovation Co Ltd

Inventors

• Lim Jin-Sub
• Han Kook-Hyun
• Hwang Duck-Chul

Classifications

• H01M4/505

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

• H01M4/485 Primary

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/625

  Carbon or graphite · 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

• Y02E60/10

  Energy storage using batteries · CPC title