# US 12,603,327 B2 · Lithium secondary cell

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- Number: US 12,603,327 B2
- Document ID: US12603327B2
- Status: Granted
- Kind: B2
- Application number: 17/303,966
- Filed: 2021-06-11
- Published: 2021-09-30
- Granted: 2026-04-14
- Earliest claimed: 2019-02-27
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Haruo Otsuka; Tetsushige Yoshida
- Web page: https://patentgrep.com/patent/US12603327B2

## CPC

- H01M 10/0585: of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/382: {Lithium (H01M4/405 takes precedence)}
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/622: {being polymers}
- H01M 4/664: {Ceramic materials}
- H01M 4/667: {in the form of layers, e.g. coatings}
- H01M 4/70: characterised by shape or form
- H01M 10/052: Li-accumulators
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 50/136: Flexibility or foldability
- H01M 50/105: Pouches or flexible bags
- 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

In a lithium secondary cell, a positive electrode includes a sheet-like positive current collector having conductivity and a positive active material plate that is a plate-like ceramic sintered body containing a lithium composite oxide. The positive active material plate is bonded to the positive current collector via a conductive bonding layer. The positive active material plate is penetrated by the conductive bonding layer through a surface of the positive active material plate facing the positive current collector. A penetration depth of the conductive bonding layer in the positive active material plate with respect to a direction of superposition is 3% or more and 80% or less of a thickness of the positive active material plate.

## Claims

### Claim 1

A lithium secondary cell comprising:
a positive electrode;
a separator arranged on said positive electrode in a predetermined direction of superposition;
a negative electrode arranged on said separator on a side opposite to said positive electrode in said direction of superposition;
an electrolytic solution with which said positive electrode, said negative electrode, and said separator are impregnated; and
a sheet-like cell case that covers said positive electrode and said negative electrode from both sides in said direction of superposition and houses therein said positive electrode, said separator, said negative electrode, and said electrolytic solution,
wherein one electrode of said positive electrode and said negative electrode includes:
a sheet-like current collector having conductivity; and
an active material plate that is a plate-like ceramic sintered body containing a lithium composite oxide, said active material plate being bonded to said current collector via a conductive bonding layer,
said conductive bonding layer penetrates into said active material plate through an entire surface of said active material plate facing said current collector,
a penetration depth of said conductive bonding layer in said active material plate with respect to said direction of superposition is 3% or more and 80% or less of a thickness of said active material plate.

### Claim 2 (depends on 1)

The lithium secondary cell according to claim 1, wherein
said one electrode is said positive electrode, and
said negative electrode comprises:
a sheet-like negative current collector having conductivity; and
a negative active material layer containing a carbonaceous material or a lithium-occluding material, said negative active material layer being applied as a coat on said negative current collector.

### Claim 3 (depends on 1)

The lithium secondary cell according to claim 1, wherein
said conductive bonding layer includes:
conductive powder; and
a binder containing a resin and an aqueous solvent.

### Claim 4 (depends on 3)

The lithium secondary cell according to claim 3, wherein
said resin contained in said conductive bonding layer is an acrylic resin.

### Claim 5 (depends on 1)

The lithium secondary cell according to claim 1, wherein
said active material plate has a porosity of 25% or more and 45% or less.

### Claim 6 (depends on 1)

The lithium secondary cell according to a claim 1, being used as a power supply source of a sheet-like device or a device having flexibility.

### Claim 7 (depends on 6)

The lithium secondary cell according to claim 6, being used as a power supply source of a smart card that is said device having flexibility.