Nonaqueous electrolyte secondary battery including trilithium phosphate and lithium fluorosulfonate

Patent metadata

Field	Value
Publication number	US-11094926-B2
Application number	US-201816113380-A
Country	US
Kind code	B2
Filing date	Aug 27, 2018
Priority date	Sep 11, 2017
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

Provided is a nonaqueous electrolyte secondary battery in which lithium fluorosulfonate is added to a nonaqueous electrolytic solution and which exhibits excellent low-temperature performance. The nonaqueous electrolyte secondary battery disclosed herein includes a positive electrode, a negative electrode, and a nonaqueous electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes trilithium phosphate and, as a positive electrode active material, a lithium transition metal composite oxide including at least lithium, nickel, manganese, and cobalt. The nonaqueous electrolytic solution includes lithium fluorosulfonate. A mass ratio of trilithium phosphate to the positive electrode active material is 1% by mass or more and 5% by mass or less. A content of lithium fluorosulfonate in the nonaqueous electrolytic solution is 0.15% by mass or more and 1.0% by mass or less.

First claim

What is claimed is:

1. A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution, wherein
the positive electrode includes a positive electrode active material layer;
the positive electrode active material layer includes trilithium phosphate and, as a positive electrode active material, a lithium transition metal composite oxide having a layered rock salt type structure and being represented by the following formula (1);
the nonaqueous electrolytic solution includes lithium fluorosulfonate, lithium bis(oxalato)borate, and lithium difluorophosphate;
a mass ratio of the trilithium phosphate to the positive electrode active material is 1% by mass or more and 5% by mass or less;
a content of the lithium fluorosulfonate in the nonaqueous electrolytic solution is 0.15% by mass or more and 1.0% by mass or less;
a content of the lithium bis(oxalato)borate in the nonaqueous electrolytic solution is 0.1% by mass or more;
a content of the lithium difluorophosphate in the nonaqueous electrolytic solution is 0.1% by mass or more; and
the trilithium phosphate has a particulate shape with an average particle diameter of 10 μm or less,
Li a Ni x Mn y Co z O 2   (1),

wherein, in formula (1), a satisfies 0.98≤a≤1.20; x, y and z satisfy x+y+z=1; x satisfies 0.20≤x≤0.60; y satisfies 0<y≤0.50; and z satisfies 0<z≤0.50.

2. The nonaqueous electrolyte secondary battery according to claim 1 , wherein x satisfies 0.34≤x≤0.60.

3. The nonaqueous electrolyte secondary battery according to claim 1 , wherein a content of the lithium bis(oxalato)borate in the nonaqueous electrolytic solution is 0.5% by mass or more.

4. The nonaqueous electrolyte secondary battery according to claim 1 , wherein a content of the lithium difluorophosphate in the nonaqueous electrolytic solution is 0.5% by mass or more.

Assignees

• Toyota Motor Co Ltd

Inventors

• Nakayama Tetsuri

Classifications

• 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

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M10/0525

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

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title