# US 12,015,141 B2 · Non-aqueous electrolyte secondary battery

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- Number: US 12,015,141 B2
- Document ID: US12015141B2
- Status: Granted
- Kind: B2
- Application number: 17/484,070
- Filed: 2021-09-24
- Published: 2022-04-28
- Granted: 2024-06-18
- Earliest claimed: 2020-10-26
- Assignees: Prime Planet Energy & Solutions, Inc.
- Applicants: Prime Planet Energy & Solutions, Inc.
- Inventors: Atsushi Obayashi; Hikaru Yoshida
- Web page: https://patentgrep.com/patent/US12015141B2

## CPC

- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/139: Processes of manufacture
- H01M 4/0404: {by coating on electrode collectors}
- H01M 4/043: {involving compressing or compaction}
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- H01M 4/049: {Manufacturing of an active layer by chemical means}
- H01M 10/05: Accumulators with non-aqueous electrolyte (H01M10/39 takes precedence)
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/058: Construction or manufacture
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/1393: of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative electrodes}
- 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 non-aqueous electrolyte secondary battery comprises a positive electrode, a negative electrode, a separator, and an electrolyte solution. At least part of the separator is interposed between the positive electrode and the negative electrode. The negative electrode includes a negative electrode substrate and a negative electrode active material layer. The negative electrode active material layer is placed on a surface of the negative electrode substrate. Voids are formed in the negative electrode active material layer. In a cross section parallel to a thickness direction of the negative electrode active material layer, the voids have an average equivalent circle diameter from 9.6 μm to 35.8 μm, an average circularity of 0.26 or more, and an area percentage from 3.1% to 30.9%.

## Claims

### Claim 1

A non-aqueous electrolyte secondary battery comprising:
a positive electrode;
a negative electrode;
a separator; and
an electrolyte solution, wherein
at least part of the separator is interposed between the positive electrode and the negative electrode,
the negative electrode includes a negative electrode substrate and a negative electrode active material layer,
the negative electrode active material layer is placed on a surface of the negative electrode substrate,
in a cross section parallel to the thickness direction of the negative electrode active material layer, the negative electrode active material layer is divided into two equal parts in the thickness direction, and thus the negative electrode active material layer is separated into a first region and a second region,
the first region includes a surface of the negative electrode active material layer,
the second region includes an interface between the negative electrode active material layer and the negative electrode substrate,
the negative electrode active material layer includes a plurality of negative electrode active material particles,
each of the negative electrode active material particles consists of a negative electrode active material,
voids are formed in the first region of the negative electrode active material layer and in the second region of the negative electrode active material layer,
an average circularity of the voids in the first region of the negative electrode active material layer is 0.26 or more, and an average circularity of the voids in the second region of the negative electrode active material layer is less than 0.26,
each of the voids is surrounded by the plurality of negative electrode active material particles, and
in a cross section parallel to a thickness direction of the negative electrode active material layer,
the voids have:
an average equivalent circle diameter from 9.6 μm to 35.8 μm; and
an area percentage from 3.1% to 30.9%.

### Claim 2 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the voids have an area percentage of 25.2% or less.

### Claim 3 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein an average equivalent circle diameter of the voids is greater than a particle size of each of the negative electrode active material particles.

### Claim 4 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein each of the negative electrode active material particles includes at least one component selected from the group consisting of graphite, soft carbon, and hard carbon.

### Claim 5 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode active material layer further includes copper deposited inside the voids.

### Claim 6 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the voids have an average equivalent circle diameter from 21.5 μm to 35.8 μm.

### Claim 7 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode active material layer has a density of from 1.05 g/cm3 to 1.3 g/cm3.

### Claim 8 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode active material has a BET specific surface area of from 1 m2/g to 10 m2/g.

### Claim 9 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein an area percentage of the voids in the first region is higher than an area percentage of the voids in the second region.

### Claim 10 (depends on 1)

The non-aqueous electrolyte secondary battery according to claim 1, wherein the voids have an average equivalent circle diameter from 9.6 μm to 35.8 μm in the first region, and the voids have an average equivalent circle diameter of less than 9.6 μm in the second region.