Positive electrode active material of power storage device, power storage device, electrically propelled vehicle, and method for manufacturing power storage

Patent metadata

Field	Value
Publication number	US-12027702-B2
Application number	US-202117160735-A
Country	US
Kind code	B2
Filing date	Jan 28, 2021
Priority date	Apr 28, 2010
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

An object is to improve the characteristics of a power storage device such as a charging and discharging rate or a charge and discharge capacity. The grain size of particles of a positive electrode active material is nano-sized so that a surface area per unit mass of the active material is increased. Specifically, the grain size is set to greater than or equal to 10 nm and less than or equal to 100 nm, preferably greater than or equal to 20 nm and less than or equal to 60 nm. Alternatively, the surface area per unit mass is set to 10 m 2 /g or more, preferably 20 m 2 /g or more, further, the crystallinity of the active material is increased by setting an XRD half width to greater than or equal to 0.12° and less than 0.17°, preferably greater than or equal to 0.13° and less than 0.16°.

First claim

What is claimed is:

1. An active material particle,
wherein the active material particle comprises lithium iron phosphate,
wherein a grain size of the active material particle is greater than or equal to 10 nm and less than or equal to 100 nm, and
wherein an X-ray diffraction half width of the active material particle is greater than or equal to 0.13° and less than 0.16°.

2. An electrode comprising:
a current collector;
an active material layer over the current collector, the active material layer comprising:
the active material particle according to claim 1 ; and
a binder comprising a polymer.

3. A power storage device comprising:
a positive electrode comprising the active material particle according to claim 1 ;
a negative electrode; and
an electrolyte between the positive electrode and the negative electrode.

4. The power storage device according to claim 3 ,
wherein a rate characteristic of the power storage device is 0.85 or more,
wherein the rate characteristic is defined by a rate of a discharge capacity in a case where a discharge rate is 10 C with respect to a discharge capacity in a case where a discharge rate is 2 C, and
wherein discharging n times in an hour is expressed as n C.

5. An electrically propelled vehicle comprising the power storage device according to claim 3 .

6. An active material particle comprising:
a region comprising lithium iron phosphate;
a carbon layer on a surface of the active material particle,
wherein the region comprising lithium iron phosphate comprises a crystal of lithium iron phosphate,
wherein a grain size of the active material particle is greater than or equal to 10 nm and less than or equal to 100 nm, and
wherein an X-ray diffraction half width of the crystal is greater than or equal to 0.13° and less than 0.16°.

7. An electrode comprising:
a current collector;
an active material layer over the current collector, the active material layer comprising:
the active material particle according to claim 6 ; and
a binder comprising polyvinylidene fluoride.

8. A power storage device comprising:
a positive electrode comprising the active material particle according to claim 6 ;
a negative electrode; and
an electrolyte between the positive electrode and the negative electrode.

9. The power storage device according to claim 8 ,
wherein a rate characteristic of the power storage device is 0.85 or more,
wherein the rate characteristic is defined by a rate of a discharge capacity in a case where a discharge rate is 10 C with respect to a discharge capacity in a case where a discharge rate is 2 C, and
wherein discharging n times in an hour is expressed as n C.

10. An electrically propelled vehicle comprising the power storage device according to claim 8 .

Assignees

• Semiconductor Energy Lab

Inventors

• Kawakami Takahiro
• Yamakaji Masaki

Classifications

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0436

  Small-sized flat cells or batteries for portable equipment · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title