US 9,287,557 B2 · Method for manufacturing nonaqueous electrolyte secondary battery

Abstract

When an active material with low ionic conductivity and low electric conductivity is used in a nonaqueous electrolyte secondary battery such as a lithium ion battery, it is necessary to reduce the sizes of particles; however, reduction in sizes of particles leads to a decrease in electrode density. Active material particles of an oxide, which include a transition metal and have an average size of 5 nm to 50 nm, are mixed with an electrolyte, a binder, and the like to form a slurry, and the slurry is applied to a collector. Then, the collector coated with the slurry is exposed to a magnetic field. Accordingly, the active material particles aggregate so that the density thereof increases. Alternatively, the active material particles may be applied to the collector in a magnetic field. The use of the aggregating active material particles makes it possible to increase the electrode density.

Claims12

Dependent claims

A method for manufacturing a nonaqueous electrolyte secondary battery, comprising:

forming a slurry including active material particles of an oxide, a binder and a conduction auxiliary agent, wherein each of the active material particles comprises a transition metal, and an average value of cube roots of volume of each of the active material particles is 5 nm to 50 nm;
applying the slurry to a surface of a current collector;
exposing the current collector coated with the slurry to a non-uniform magnetic field to separate the slurry into a first portion of the slurry that includes the binder and the conduction auxiliary agent, and does not substantially include the active material particles and a second portion of the slurry that contains most of the active material particles and is located between the current collector and the first portion of the slurry;
and
selectively removing the first portion of the slurry,
wherein a maximum of the non-uniform magnetic field at the surface of the current collector is 0.01 T to 2 T, and
wherein the step of selectively removing the first portion of the slurry is followed by a step of drying the second portion of the slurry.

4 more elements

Dependencies are inferred from the claim text.

Method for manufacturing nonaqueous electrolyte secondary battery

Life of this patent

Method for manufacturing nonaqueous electrolyte secondary battery

Life of this patent

Abstract

Claims12