Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-12087942-B2
Application number	US-202017442058-A
Country	US
Kind code	B2
Filing date	Mar 23, 2020
Priority date	Mar 29, 2019
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

A non-aqueous electrolyte secondary battery, wherein a negative electrode includes a negative electrode mixture layer having a thickness T and a negative electrode current collector, the negative electrode active material includes carbon and Si-containing materials, wherein when the negative electrode mixture layer is divided into a first region having a thickness of T/2 on the surface side of the negative electrode and a second region having a thickness of T/2 on the negative electrode collector side, a mass ratio of the first to the second composite material contained in the first region is >1, a mass ratio of the first composite to the second composite material contained in the second region is <1, and, in a fully charged condition, an open circuit potential of the negative electrode is 0 V or more and 70 mV or less with respect to a lithium metal.

First claim

The invention claimed is:

1. A non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, an electrolyte and a separator disposed between the positive electrode and the negative electrode,
the negative electrode including a negative electrode mixture layer having a thickness T and a negative electrode current collector carrying the negative electrode mixture layer,
the negative electrode active material including a carbon material and a Si-containing material,
the Si-containing material including a first composite material and a second composite material different from the first composite material,
the first composite material including a silicon oxide phase and a first Si particles dispersed in the silicon oxide phase,
wherein when the negative electrode mixture layer is divided into a first region having a thickness of T/2 on the surface side of the negative electrode and a second region having a thickness of T/2 on the negative electrode collector side,
a ratio of a mass w11 of the first composite material contained in the first region to a mass w12 of the second composite material contained in the first region: w11/w12 is greater than 1,
a ratio of a mass w21 of the first composite material contained in the second region to a mass w22 of the second composite material contained in the second region: w21/w22 is less than 1, and,
in a fully charged condition, an open circuit potential of the negative electrode is 0 V or more and 70 mV or less with respect to a lithium metal.

2. The non-aqueous electrolyte secondary battery according to claim 1 , wherein, the ratio of a mass W1 of the first composite material contained in the negative electrode mixture layer to a mass W2 of the second composite material contained in the negative electrode mixture layer:
W1/W2 is from 1.0/19.0 to 19.0/1.0.

3. The non-aqueous electrolyte secondary battery according to claim 1 , wherein,
the second composite material includes a lithium-ion conductive phase and second Si particles dispersed in the lithium-ion conductive phase,
the lithium-ion conductive phase is a silicate phase and/or a carbon phase, and
the silicate phase includes at least one selected from the group consisting of group 1 elements and group 2 elements of a long period type periodic table.

4. The non-aqueous electrolyte secondary battery according to claim 1 , wherein an irreversible capacity of the first composite material is larger than an irreversible capacity of the second composite material.

5. The non-aqueous electrolyte secondary battery according to claim 1 , wherein an average particle diameter of the second Si particles is 100 nm or more and 500 nm or less.

6. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a ratio of a capacity Cn of the negative electrode to a capacity Cp of the positive electrode: Cn/Cp is greater than 0 and less than 1.

7. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a ratio of a mass Wc of the carbon material contained in the negative electrode mixture layer to a mass Ws of the Si-containing material contained in the negative electrode mixture layer: Wc/Ws is from 70/30 to 99/1.

8. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a content of the first Si particles contained in the first composite material is 20 mass % or more and 60 mass % or less.

9. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a content of the second Si particles contained in the second composite material is 40 mass % or more and 80 mass % or less.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Tani Yuji
• Sakamoto Junichi
• Hojo Nobuhiko

Classifications

• H01M4/485

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

• H01M2010/4292

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

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M2004/027

  Negative electrodes · CPC title