Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-11949097-B2
Application number	US-201917271348-A
Country	US
Kind code	B2
Filing date	Feb 25, 2019
Priority date	Aug 29, 2018
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

In a nonaqueous electrolyte secondary battery a separator includes a porous substrate, a first filler layer, and a second filler layer. The first filler layer comprises phosphate particles having a BET specific surface area of 5 to 100 m2/g and polyvinylidene fluoride and is formed on a first surface that faces the positive electrode side of the substrate and contacts the positive electrode. The second filler comprises inorganic particles which have a melting point higher than that of the phosphate particles and is formed on at least one of a second surface that faces the negative electrode side of the substrate and the area between the substrate and the first filler layer. The content of the polyvinylidene fluoride in the first filler layer is 10 to 50 mass % and is higher in a region on the positive electrode side than in a region on the substrate side.

First claim

The invention claimed is:

1. A non-aqueous electrolyte secondary battery comprising:
a positive electrode;
a negative electrode; and
a separator interposed between the positive electrode and the negative electrode,
a mixture layer density of the positive electrode being 3.6 g/cc or more, wherein
the separator includes:
a porous base material;
a first filler layer including phosphate particles having a BET specific surface area of 5 m 2 /g or more and 100 m 2 /g or less and polyvinylidene fluoride and formed on a first surface of the base material facing a side of the positive electrode and being in contact with the positive electrode; and
a second filler layer including inorganic particles having a melting point higher than that of the phosphate particles and formed at least one of on a second surface of the base material facing a side of the negative electrode and between the base material and the first filler layer, wherein
a content of polyvinylidene fluoride included in the first filler layer is 10% by mass or more and 50% by mass or less, and is higher in a region on the positive electrode side than in a region on the base material side,
in the first filler layer, a content of the phosphate particles is at least 50% by mass based on a total mass of the first filler layer, and
in the second filler layer, a content of the inorganic particles having a melting point higher than that of the phosphate particles is 90% by mass or more based on a total mass of the second filler layer.

2. The non-aqueous electrolyte secondary battery according to claim 1 , wherein when the first filler layer is divided in half at a center in a thickness direction, a content of polyvinylidene fluoride present in the region located on the positive electrode side is more than 50% by mass and 80% by mass or less of a total mass of polyvinylidene fluoride included in the entire first filler layer.

3. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the base material includes a polyolefin as a main component.

4. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the second filler layer is formed on the second surface of the base material.

5. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the phosphate particles are at least one selected from lithium phosphate, dilithium hydrogen phosphate, and lithium dihydrogen phosphate.

6. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the second filler layer is formed between the base material and the first filler layer.

7. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the phosphate particles include at least one selected from the group consisting of LiPON, Li 2 HPO 4 , LiH 2 PO 4 , Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 , Zr 3 (PO 4 ) 4 , Zr(HPO 4 ) 2 , HZr 2 (PO 4 ) 3 , K 3 PO 4 , K 2 HPO 4 , KH 2 PO 4 , Ca 3 (PO 4 ) 2 , CaHPO 4 , Mg 3 (PO 4 ) 2 , MgHPO 4 , and combinations thereof.

8. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the BET specific surface area of the phosphate particles is from 7.1 m 2 /g to 54.07 m 2 /g.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Baba Yasunori
• Sugimori Masanori
• Yanagida Katsunori
• Hirano Nobuhiro

Classifications

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/621

  Binders · CPC title

• H01M4/624

  Electric conductive fillers · CPC title

• H01M4/762

  Porous or perforated metallic containers · CPC title

• H01M50/431

  Inorganic material · CPC title