# US 8,785,047 B2 · Lithium-ion secondary battery and method of charging lithium-ion secondary battery

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,785,047 B2
- Document ID: US8785047B2
- Status: Granted
- Kind: B2
- Application number: 11/066,247
- Filed: 2005-02-25
- Published: 2005-10-20
- Granted: 2014-07-22
- Earliest claimed: 2004-02-25
- Assignees: TDK Corporation
- Applicants: Kazuya Ogawa; Tsuyoshi Iijima; Satoshi Maruyama
- Inventors: Kazuya Ogawa; Tsuyoshi Iijima; Satoshi Maruyama
- Web page: https://patentgrep.com/patent/US8785047B2

## CPC

- H01M 4/587: for inserting or intercalating light metals
- H01M 10/0436: {Small-sized flat cells or batteries for portable equipment}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 4/02: Electrodes composed of, or comprising, active material
- H01M 6/42: Grouping of primary cells into batteries (H01M6/40 takes precedence)
- H01M 10/0585: of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
- H01M 50/119: Metals
- H01M 50/121: Organic material
- H01M 50/124: having a layered structure
- H01M 50/136: Flexibility or foldability
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2300/004: Three solvents
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A lithium-ion secondary battery device comprises a positive electrode collector having a surface formed with a positive electrode active material layer containing a positive electrode active material; a negative electrode collector having a surface formed with a negative electrode active material layer containing a negative electrode active material; an electrically insulating porous separator; and an electrolyte containing a lithium salt and being in contact with the positive electrode active material layer, negative electrode active material layer, and separator. The negative electrode active material is a carbon material having a graphite structure. The amount of the carbon material supported by the negative electrode active material layer is 2.0 to 4.0 mg/cm2. The graphite structure in an X-ray diffraction pattern of the carbon material exhibits a peak intensity P101 of (101) plane and a peak intensity P100 of (100) plane having a ratio (P101/P100) of 2.0 to 2.8 therebetween.

## Claims

### Claim 1

A lithium-ion secondary battery comprising:
a positive electrode collector having a surface formed with a positive electrode active material layer containing a positive electrode active material;
a negative electrode collector having a surface formed with a negative electrode active material layer containing a negative electrode active material;
an electrically insulating porous separator; and
an electrolyte containing a lithium salt and being in contact with the positive electrode active material layer, the negative electrode active material layer, and the separator;
wherein the positive and negative electrode collectors are disposed such that the positive and negative electrode active material layers hold the separator therebetween;
wherein the negative electrode active material is a carbon material having a graphite structure;
wherein the amount of the carbon material supported by the negative electrode active material layer is 2.2 to 4.0 mg/cm2; and
wherein the graphite structure in an X-ray diffraction pattern of the carbon material exhibits a peak intensity P101 of (101) plane and a peak intensity P100 of (100) plane having a ratio (P101/P100) of 2.4 to 2.8 therebetween.

### Claim 2 (depends on 1)

A lithium-ion secondary battery according to claim 1, wherein the amount of the positive electrode active material supported by the positive electrode active material layer is 4.0 to 7.0 mg/cm2.

### Claim 3 (depends on 1)

A lithium-ion secondary battery according to claim 1, wherein a plurality of secondary battery elements each including the positive electrode collector, the negative electrode collector, and the separator are laminated.

### Claim 4 (depends on 1)

A method of rapidly charging a lithium-ion secondary battery, the method comprising the step of subjecting the lithium-ion secondary battery according to claim 1 to constant-voltage charging at 4.2 V.

### Claim 5 (depends on 1)

A lithium-ion secondary battery according to claim 1, wherein the carbon material is natural graphite or synthetic graphite.

### Claim 6 (depends on 1)

A lithium-ion secondary battery according to claim 1, wherein the amount of the carbon material supported by the negative electrode active material layer is 3.0 to 4.0 mg/cm2.

### Claim 7 (depends on 1)

A lithium-ion secondary battery according to claim 1, wherein the amount of the carbon material supported by the negative electrode active material layer is 2.2 to 3.3 mg/cm2.