Lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2024332522-A1
Application number	US-202418738334-A
Country	US
Kind code	A1
Filing date	Jun 10, 2024
Priority date	Dec 24, 2021
Publication date	Oct 3, 2024
Grant date	—

Abstract

Provided is a lithium secondary battery, including: a positive electrode layer including a lithium composite oxide sintered body; a negative electrode layer; a separator interposed between the positive electrode layer and the negative electrode layer; an electrolytic solution impregnated into the positive electrode layer, the negative electrode layer, and the separator; and an exterior body, which has a closed space and is configured to store the positive electrode layer, the negative electrode layer, the separator, and the electrolytic solution in the closed space. This lithium secondary battery has a determination coefficient R2 of 0.8 or more, which is obtained when plots of a square root of the number of days elapsed of up to 180 days and a capacity maintenance ratio (%) in a float charging test are linearly regressed.

First claim

1 . A lithium secondary battery, comprising:
a positive electrode layer including a lithium composite oxide sintered body; a negative electrode layer; a separator interposed between the positive electrode layer and the negative electrode layer; an electrolyte impregnated into the positive electrode layer, the negative electrode layer, and the separator; and an exterior body, which has a closed space and is configured to store the positive electrode layer, the negative electrode layer, the separator, and the electrolyte in the closed space, wherein the lithium secondary battery has a determination coefficient R 2 of 0.8 or more, which is obtained when plots of a square root of the number of days elapsed of up to 180 days and a capacity maintenance ratio (%) in a float charging test are linearly regressed.

2 . The lithium secondary battery according to claim 1 , wherein the lithium secondary battery is a pouch-type battery in which the exterior body is a laminated film including a resin film and metal foil, and which has a thickness of 0.5 mm or less.

3 . The lithium secondary battery according to claim 1 , wherein the lithium secondary battery is a coin-type battery in which the exterior body is a metal can including a positive electrode can and a negative electrode can, and the exterior body has a diameter of 25 mm or less and a thickness of 2 mm or less.

4 . The lithium secondary battery according to claim 1 , wherein the capacity maintenance ratio (%) in the float charging test, which represents a battery capacity at a time of a lapse of 180 days with respect to a battery capacity at a time of a start of the test, is 35% or more.

5 . The lithium secondary battery according to claim 1 , wherein the negative electrode layer includes a titanium-containing sintered body.

6 . The lithium secondary battery according to claim 1 ,
wherein the separator is a ceramic separator, and wherein the positive electrode layer, the negative electrode layer, and the separator serve as one integrated sintered body as a whole.

7 . The lithium secondary battery according to claim 1 , wherein the positive electrode layer has a specific surface area of 1.9 m 2 /g or less.

8 . The lithium secondary battery according to claim 2 , wherein the capacity maintenance ratio (%) in the float charging test, which represents a battery capacity at a time of a lapse of 180 days with respect to a battery capacity at a time of a start of the test, is 35% or more.

9 . The lithium secondary battery according to claim 2 , wherein the negative electrode layer includes a titanium-containing sintered body.

10 . The lithium secondary battery according to claim 2 ,
wherein the separator is a ceramic separator, and wherein the positive electrode layer, the negative electrode layer, and the separator serve as one integrated sintered body as a whole.

11 . The lithium secondary battery according to claim 2 , wherein the positive electrode layer has a specific surface area of 1.9 m 2 /g or less.

12 . The lithium secondary battery according to claim 3 , wherein the capacity maintenance ratio (%) in the float charging test, which represents a battery capacity at a time of a lapse of 180 days with respect to a battery capacity at a time of a start of the test, is 35% or more.

13 . The lithium secondary battery according to claim 3 , wherein the negative electrode layer includes a titanium-containing sintered body.

14 . The lithium secondary battery according to claim 3 ,
wherein the separator is a ceramic separator, and wherein the positive electrode layer, the negative electrode layer, and the separator serve as one integrated sintered body as a whole.

15 . The lithium secondary battery according to claim 3 , wherein the positive electrode layer has a specific surface area of 1.9 m 2 /g or less.

Assignees

• Ngk Insulators Ltd

Inventors

• MITSUHASHI Takuaki
• Iida Daisuke
• Nakashima Eiji

Classifications

• 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

• H01M4/485 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

• H01M2004/021

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M50/109

  of button or coin shape · CPC title