US 2008/0292965 A1 · RECHARGEABLE LITHIUM ION BATTERY AND METHOD FOR PRODUCING THE SAME

Abstract

The present invention relates to a rechargeable lithium ion battery having an electrode plate with a high active material density and high electrolyte permeability. Upon producing the rechargeable lithium ion battery, hollow resin particles that can be collapsed by rolling are incorporated in a positive electrode mixture layer or a negative electrode mixture layer before the electrode mixture layer is rolled. The hollow resin particles are collapsed in the course of rolling the positive electrode mixture layer or the negative electrode mixture layer, so that the active material density can be easily increased. Further, the collapsed resin particles form unevenness on the surface of the electrode plate and also form open pores in the electrode plate, so that electrolyte permeability can be enhanced. As a result, the discharge capacity and rate characteristics of rechargeable lithium ion batteries can be increased.

Claims11

Dependent claims

A rechargeable lithium ion battery, comprising:

a positive electrode having a positive electrode mixture layer;
a negative electrode having a negative electrode mixture layer;
and
a separator disposed between the positive electrode and the negative electrode, wherein
the positive electrode mixture layer or the negative electrode mixture layer contains resin particles, and
when a scanning electron microscope image of the surface of the positive electrode mixture layer or the negative electrode mixture layer containing the resin particles is reduced to a 256 gray-scale image and then is binarized into black pixels and white pixels at a threshold of 70, a ratio of the total area of the black pixels to the total area of entire pixels is 10% or more and 20% or less.

3 more elements

A method for producing a rechargeable lithium ion battery comprising the steps of:

forming a positive electrode having a positive electrode mixture layer and a positive electrode current collector by coating a positive electrode paint containing a positive electrode active material at a positive electrode active material density on the positive electrode current collector;
forming a negative electrode having a negative electrode mixture layer and a negative electrode current collector by coating a negative electrode paint containing a negative electrode active material at a negative electrode active material density on the negative electrode current collector;
increasing the positive electrode active material density in the positive electrode mixture layer by rolling the positive electrode;
increasing the negative electrode active material density in the negative electrode mixture layer by rolling the negative electrode;
and
stacking in layers the positive electrode after rolling, a separator, and the negative electrode after rolling, wherein
the positive electrode paint or the negative electrode paint further contains hollow resin particles.

4 more elements

Dependencies are inferred from the claim text.

Rechargeable lithium ion battery and method for producing the same

Life of this patent

Rechargeable lithium ion battery and method for producing the same

Life of this patent

Abstract

Claims11