# US 12,183,874 B2 · Lithium secondary battery

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- Number: US 12,183,874 B2
- Document ID: US12183874B2
- Status: Granted
- Kind: B2
- Application number: 17/095,910
- Filed: 2020-11-12
- Published: 2021-03-04
- Granted: 2024-12-31
- Earliest claimed: 2018-05-17
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Yukinobu Yura; Shigeki Okada; Kengo Oishi
- Web page: https://patentgrep.com/patent/US12183874B2

## CPC

- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence)
- H01M 4/525: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
- H01M 10/0427: {Button cells}
- H01M 10/0585: of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
- H01M 50/10: Primary casings; Jackets or wrappings
- H01M 50/409: Separators, membranes or diaphragms characterised by the material
- H01M 50/431: Inorganic material
- H01M 50/434: Ceramics
- H01M 50/437: Glass
- H01M 50/46: Separators, membranes or diaphragms characterised by their combination with electrodes
- 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
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 50/491: Porosity
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- 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

Provided is a lithium secondary battery including a positive electrode layer composed of a cobalt-containing lithium complex oxide sintered body, a negative electrode layer composed of a titanium-containing sintered body, a ceramic separator interposed between the positive electrode layer and the negative electrode layer and containing MgO, an electrolytic solution with which the positive electrode layer, the negative electrode layer, and the ceramic separator are impregnated, and an exterior body including a closed space, the closed space accommodating the positive electrode layer, the negative electrode layer, the ceramic separator, and the electrolytic solution, wherein the positive electrode layer, the ceramic separator, and the negative electrode layer are bonded together, and the interface between the negative electrode layer and the ceramic separator has a larger roughness than the interface between the positive electrode layer and the ceramic separator.

## Claims

### Claim 1

A lithium secondary battery comprising:
a positive electrode layer composed of a cobalt-containing lithium complex oxide sintered body;
a negative electrode layer composed of a titanium-containing sintered body;
a ceramic separator interposed between the positive electrode layer and the negative electrode layer and containing MgO;
an electrolytic solution with which the positive electrode layer, the negative electrode layer, and the ceramic separator are impregnated; and
an exterior body comprising a closed space, the closed space accommodating the positive electrode layer, the negative electrode layer, the ceramic separator, and the electrolytic solution,
wherein the positive electrode layer, the ceramic separator, and the negative electrode layer form one integrated sintered plate as a whole, whereby the positive electrode layer, the ceramic separator, and the negative electrode layer are bonded together, and
wherein an interface between the negative electrode layer and the ceramic separator has a larger roughness than an interface between the positive electrode layer and the ceramic separator.

### Claim 2 (depends on 1)

The lithium secondary battery according to claim 1, wherein a ratio of an average surface roughness at the interface between the negative electrode layer and the ceramic separator with respect to an average surface roughness at the interface between the positive electrode layer and the ceramic separator is 1.2 to 10.0.

### Claim 3 (depends on 1)

The lithium secondary battery according to claim 1, wherein the lithium complex oxide is lithium cobaltate.

### Claim 4 (depends on 1)

The lithium secondary battery according to claim 1, wherein the positive electrode layer has a thickness of 60 to 600 μm.

### Claim 5 (depends on 1)

The lithium secondary battery according to claim 1, wherein the positive electrode layer is an oriented positive electrode layer containing a plurality of primary grains composed of the lithium complex oxide, the plurality of primary grains being oriented at an average orientation angle of over 0° and 30° or less with respect to the layer face of the positive electrode layer.

### Claim 6 (depends on 1)

The lithium secondary battery according to claim 1, wherein the negative electrode layer has a thickness of 70 to 800 μm.

### Claim 7 (depends on 1)

The lithium secondary battery according to claim 1, wherein the titanium-containing sintered body comprises lithium titanate or niobium titanium complex oxide.

### Claim 8 (depends on 1)

The lithium secondary battery according to claim 1, wherein the ceramic separator has a thickness of 5 to 50 μm.

### Claim 9 (depends on 1)

The lithium secondary battery according to claim 1, wherein the ceramic separator is composed of MgO and glass.

### Claim 10 (depends on 1)

The lithium secondary battery according to claim 1, further comprising:
a positive electrode current collector; and
a negative electrode current collector.