# US 2014/0193691 A1 · Nonaqueous electrolyte secondary battery

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- Number: US 2014/0193691 A1
- Document ID: US20140193691A1
- Status: Published application
- Kind: A1
- Application number: 14/115,220
- Filed: 2011-05-02
- Published: 2014-07-10
- Earliest claimed: 2011-05-02
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Inventors: Tomoyoshi Ueki; Hideaki Fujita; Harunari Shimamura
- Web page: https://patentgrep.com/patent/US20140193691A1

## CPC

- 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 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- 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 10/052: Li-accumulators
- H01M 50/451: comprising layers of only organic material and layers containing inorganic material
- 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 50/491: Porosity
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- 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
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A nonaqueous electrolyte secondary battery 100 according to the present invention is provided with an electrode assembly 80 having a structure in which a positive electrode 10 and a negative electrode 20 are stacked with a separator 30 interposed therebetween. A porous filler layer 32 is formed between the positive electrode 10 and the separator 30. The filler layer 32 contains a filler made of an inorganic material and contains a binder. The relationship T>D holds where T is the average thickness of the filler layer 32 and D is the average particle diameter of a positive electrode active material 15 present in the positive electrode 10 facing the filler layer 32, and a pressure applied to the electrode assembly 80 in the stacking direction is set to at least 0.1 MPa.

## Claims

### Claim 1

A nonaqueous electrolyte secondary battery comprising an electrode assembly having a structure in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween, wherein
a porous filler layer formed on a surface of the separator is disposed between the positive electrode and the separator,
the filler layer contains a filler made of an inorganic material and contains a binder,
an average particle diameter of the filler is from at least 0.5 μm to not more than 2 μm,
the proportion of the filler in the filler layer as a whole is at least 90 mass %,
an average thickness T of the filler layer is from at least 6 μm to not more than 20 μm, an average particle diameter D of a positive electrode active material present in the positive electrode facing the filler layer is at least 1 μm, and the relationship T>D holds, and
a pressure applied to the electrode assembly in the stacking direction is set to at least 0.1 MPa.

### Claim 2 (depends on 1)

The nonaqueous electrolyte secondary battery according to claim 1, wherein the difference between the average thickness T of the filler layer and the average particle diameter D of the positive electrode active material is at least 0.5 μm.

### Claim 3 (depends on 1)

The nonaqueous electrolyte secondary battery according to claim 1, wherein the average thickness T of the filler layer is at least 9 μm, and
the average particle diameter D of the positive electrode active material is not more than 8.3 μm.

### Claim 4 (depends on 1)

The nonaqueous electrolyte secondary battery according to claim 1, wherein the filler incorporated in the filler layer is at least one metal compound selected from the group consisting of alumina, magnesia, zirconia, silica, boehmite, and titanic.

### Claim 5 (depends on 1)

The nonaqueous electrolyte secondary battery according to claim 1, wherein the shape of the positive electrode active material is spherical or oval spherical.

### Claim 6 (depends on 1)

The nonaqueous electrolyte secondary battery according to claim 1, wherein
the positive electrode has, as the positive electrode active material, a lithium transition metal complex oxide that contains at least one metal element selected from the group consisting of nickel, cobalt, and manganese.

### Claim 7 (depends on 1)

A battery pack comprising a plurality of the nonaqueous electrolyte secondary batteries according to claim 1 connected in series, wherein
each of the nonaqueous electrolyte secondary batteries is provided with the electrode assembly and a battery case that houses the electrode assembly and a nonaqueous electrolyte, and
a retaining pressure applied to a surface of the battery case is set to at least 0.1 MPa.

### Claim 8 (depends on 7)

The battery pack according to claim 7, wherein the battery case is made of aluminum or an aluminum alloy.