Carbon fiber aggregate and method for manufacturing same, electrode mixture layer for non-aqueous-electrolyte secondary cell, electrode for non-aqueous-electrolyte secondary cell, and non-aqueous-electrolyte secondary cell

Patent metadata

Field	Value
Publication number	US-11387458-B2
Application number	US-201716074216-A
Country	US
Kind code	B2
Filing date	Feb 3, 2017
Priority date	Feb 5, 2016
Publication date	Jul 12, 2022
Grant date	Jul 12, 2022

Abstract

The present invention provides a carbon fiber aggregate that is characterized by comprising carbon fibers in which crystallite interplanar spacing (d002) measured using X-ray diffraction is 0.3400 nm or more, the average liber diameter being 10-900 nm, and the powder volume resistivity being 4.00×10−2 Ω·cm or less when the packing density is 0.8 g/cm3.

First claim

The invention claimed is:

1. A carbon fiber aggregate wherein the carbon fiber aggregate comprises a carbon fiber of 0.3400 nm or more in crystallite spacing (d002) in accordance with an X-ray diffraction method, and has an average fiber diameter of 10 to 900 nm, and a powder volume resistivity at a packing density of 0.8 g/cm 3 is 4.00×10 −2 Ω·cm or less.

2. The carbon fiber aggregate according to claim 1 , wherein the carbon fiber aggregate is 20μm or more in average effective fiber length.

3. The carbon fiber aggregate according to claim 1 , wherein a variation coefficient of an effective fiber length is 35% or higher and 90% or lower.

4. The carbon fiber aggregate according to claim 1 , wherein an average aspect ratio is 80 or more and 10000 or less.

5. The carbon fiber aggregate according to claim 1 , wherein an average effective fiber length (A) and an average fiber length (B) satisfy the following formula (1):
0. 500< A/B< 0.900   Mathematical Formula (1).

6. The carbon fiber aggregate according to claim 1 , wherein a compression recovery degree represented by the following formula (2):
Compression Recovery Degree (%)=Volume Resistivity at Recovery/Volume Resistivity at Compression×100   Mathematical Formula (2)

is 50% or higher and 90% or lower.

7. A method for producing the carbon fiber aggregate according to claim 1 the method comprising:
(1) a fiberizing step of forming a composition composed of 100 parts by mass of a thermoplastic resin and 1 to 150 parts by mass of a mesophase pitch in a molten state, thereby fiberizing the mesophase pitch to obtain a resin composite fiber;
(2) a stabilizing step of stabilizing the resin composite fiber to obtain a resin composite stabilized fiber;
(3) a thermoplastic resin removing step of removing the thermoplastic resin from the resin composite stabilized fiber to obtain a stabilized fiber; and
(4) a heating and firing step of heating the stabilized fiber at 1,000° C. or higher and lower than 2400° C. under an inert atmosphere to obtain a carbon fiber.

8. An electrode mixture layer for a nonaqueous electrolyte secondary battery, the electrode mixture layer comprising:
the carbon fiber aggregate according to claim 1 ; and an electrode active material.

9. An electrode for a nonaqueous electrolyte secondary battery, the electrode comprising:
a current collector; and
the electrode mixture layer for a nonaqueous electrolyte secondary battery according to claim 8 , stacked on the current collector.

10. A nonaqueous electrolyte secondary battery comprising the electrode mixture layer for a nonaqueous electrolyte secondary battery according to claim 8 .

Assignees

• Teijin Ltd

Inventors

• Yachi Kazuki
• Kanematsu Asami
• Komura Shinya
• Daido Takahiro

Classifications

• D04H1/4242 Primary

  Carbon fibres · CPC title

• D01F9/21

  from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• D01F9/145 Primary

  from pitch or distillation residues · CPC title

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title