LITHIUM ION SECONDARY BATTERY

• US 20100099029A1
• Filed: 10/14/2009
• Published: 04/22/2010
• Est. Priority Date: 10/17/2008
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ugaji, Masaya, Kinoshita, Masahiro
• Application Number:
  US12/578,837
• Publication Number:
  US 20100099029A1
• Time in Patent Office: Days
• US Class Current: 429/316
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed is a lithium ion secondary battery including: a positive electrode including a positive electrode active material layer containing a positive electrode active material, and a positive electrode current collector; a negative electrode including a thin film negative electrode active material layer containing an alloy-based negative electrode active material, and a negative electrode current collector; a separator interposed between the positive electrode and the negative electrode; and an ion-permeable resin layer formed on a surface of the thin film negative electrode active material layer. In this lithium ion secondary battery, despite the use of the alloy-based negative electrode active material, the deterioration in battery performance such as cycle characteristics and output characteristics is prevented.

Claims

1. A lithium ion secondary battery comprising:

a positive electrode including a positive electrode active material layer containing a positive electrode active material, and a positive electrode current collector;

a negative electrode including a thin film negative electrode active material layer containing an alloy-based negative electrode active material, and a negative electrode current collector;

a separator interposed between the positive electrode and the negative electrode; and

an ion-permeable resin layer coating at least part of a surface of the thin film negative electrode active material layer.

2. The lithium ion secondary battery in accordance with claim 1, wherein the thin film negative electrode active material layer has a thickness of 1 μ

m to 20 μ

m.

3. The lithium ion secondary battery in accordance with claim 1, wherein the surface of the thin film negative electrode active material layer has a surface roughness of 0.1 to 2 μ

m.

4. The lithium ion secondary battery in accordance with claim 1, wherein the thin film negative electrode active material layer includes a plurality of columns, the plurality of columns contain the alloy-based negative electrode active material, a gap is present between a pair of the columns adjacent to each other, and the ion-permeable resin layer coats at least part of surfaces of the plurality of columns.

5. The lithium ion secondary battery in accordance with claim 4, wherein the ion-permeable resin layer fills at least part of the gap.

6. The lithium ion secondary battery in accordance with claim 4, wherein the pair of the columns adjacent to each other has an axis-to-axis distance of 10 μ

m to 50 μ

m.

7. The lithium ion secondary battery in accordance with claim 1, wherein at least part of the surface of the thin film negative electrode active material layer has asperities or cracks.

8. The lithium ion secondary battery in accordance with claim 7, wherein each of the cracks on the surface of the thin film negative electrode active material layer has a length of 0.1 μ

m to 20 μ

m, a width of 0.1 μ

m to 5 μ

m, and a depth of 0.1 μ

m to 20 μ

m.

9. The lithium ion secondary battery in accordance with claim 1, wherein the ion-permeable resin layer contains a polymer.

10. The lithium ion secondary battery in accordance with claim 9, wherein the polymer is at least one selected from the group consisting of fluorocarbon resin, polyacrylonitrile, polyethylene oxide, and polypropylene oxide.

11. The lithium ion secondary battery in accordance with claim 9, wherein the ion-permeable resin layer contains a supporting salt in addition to the polymer, the supporting salt containing lithium ions.

12. The lithium ion secondary battery in accordance with claim 1 further comprising an oxide layer containing SiO₂, the oxide layer being provided between the thin film negative electrode active material layer and the ion-permeable resin layer.

13. The lithium ion secondary battery in accordance with claim 1, wherein the alloy-based negative electrode active material is at least one selected from a silicon-based active material and a tin-based active material.