Secondary battery

Patent metadata

Field	Value
Publication number	US-12494476-B2
Application number	US-202017292378-A
Country	US
Kind code	B2
Filing date	Mar 12, 2020
Priority date	Mar 12, 2019
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

The present invention provides a secondary battery including a negative electrode having a negative electrode active material layer containing a negative electrode active material, a positive electrode facing the negative electrode and having a positive electrode active material layer containing a positive electrode active material, a separator interposed between the negative electrode and the positive electrode, and an electrolyte, wherein the negative electrode active material includes a silicon-based active material and an N/P ratio calculated by a specific equation is 1.92 to 2.60.

First claim

The invention claimed is:

1 . A secondary battery comprising:
a negative electrode including a negative electrode active material layer containing a negative electrode active material; a positive electrode facing the negative electrode and including a positive electrode active material layer containing a positive electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte, wherein the negative electrode active material includes a silicon-based active material, the silicon-based active material contains Si, an average particle diameter (D 50 ) of the silicon-based active material is 1 μm to 3.5 μm, a porosity of the negative electrode is 37% to 45%, and an N/P ratio calculated by Equation 1 below is 1.92 to 2.60,
N/P ratio=Discharge capacity per unit area of negative electrode/Discharge capacity per unit area of positive electrode.  [Equation 1]

2 . The secondary battery of claim 1 , wherein the N/P ratio is 1.98 to 2.45.

3 . The secondary battery of claim 1 , wherein a thickness of the negative electrode active material layer is 35 μm to 50 μm.

4 . The secondary battery of claim 1 , wherein:
the negative electrode active material layer further comprises a negative electrode conductive material and a negative electrode binder; the negative electrode active material layer includes the negative electrode active material in an amount of 50 wt % to 80 wt %; the negative electrode conductive material in an amount of 5 wt % to 20 wt %; and the negative electrode binder in an amount of 10 wt % to 30 wt %.

5 . The secondary battery of claim 4 , wherein the negative electrode binder comprises at least one selected from the group consisting of styrene butadiene rubber, acrylonitrile butadiene rubber, acrylic rubber, butyl rubber, fluoro rubber, polyvinyl alcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyacrylic acid, polyethylene glycol, polyacrylonitrile, and polyacryl amide.

6 . The secondary battery of claim 1 , wherein:
the positive electrode active material includes a lithium composite transition metal oxide, wherein the lithium composite transition metal oxide includes at least one transition metal selected from the group consisting of nickel, cobalt, manganese, and aluminum, and lithium.

7 . The secondary battery of claim 1 , wherein a ratio d 1 /d 2 of a thickness d 1 of the negative electrode active material layer to a thickness d 2 of the positive electrode active material layer is 0.4 to 0.7.

8 . The secondary battery of claim 1 , wherein the N/P ratio is 2.01 to 2.33.

9 . A secondary battery comprising:
a negative electrode including a negative electrode active material layer containing a negative electrode active material; a positive electrode facing the negative electrode and including a positive electrode active material layer containing a positive electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte, wherein the negative electrode active material includes a silicon-based active material, a porosity of the negative electrode is 37% to 45%, and an N/P ratio calculated by Equation 1 below is 1.92 to 2.60,
N/P ratio=Discharge capacity per unit area of negative electrode/Discharge capacity per unit area of positive electrode  [Equation 1]

wherein, a ratio d 1 /d 2 of the thickness d 1 of the negative electrode active material layer to the thickness d 2 of the positive electrode active material layer is 0.47 to 0.65.

10 . The secondary battery of claim 9 , wherein the N/P ratio is 1.98 to 2.16.

11 . The secondary battery of claim 9 , wherein the N/P ratio is 2.01 to 2.33.

12 . The secondary battery of claim 9 , wherein an average particle diameter (D 50 ) of the silicon-based active material is 1 μm to 3.5 μm.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Young Jae
• Yoo Jung Woo

Classifications

• H01M2010/4292

  Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode · CPC title

• H01M2004/021

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

• H01M10/0525 Primary

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

• H01M4/622

  being polymers · 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