US 2001/0026885 A1 · Lithium secondary battery

Abstract

A lithium secondary battery includes a battery case, an internal electrode body contained in the battery case and including a positive electrode, a negative electrode and a separator made of porous polymer, the positive electrode and the negative electrode are wound or laminated. A working volume ratio of the positive active material and the negative active material obtained by the positive active material weight being divided by the negative active material weight is within the range from 40% to 90% of the theoretical working volume ratio. The lithium secondary battery has high safety as well as high energy density by controlling the working volume of an electrode active material and the dispersion of the distribution of the working volume and in particular is preferably used for a drive motor of an electric vehicle.

Claims10

Dependent claims

A lithium secondary battery comprising:

a battery case;
and
an internal electrode body contained in the battery case and including a positive electrode, a negative electrode and a separator made of porous polymer, the positive electrode and the negative electrode being wound or laminated so that the positive electrode and negative electrode are not brought into direct contact with each other via the separator,
wherein a working volume ratio of the positive active material and the negative active material obtained by the positive active material weight being divided by the negative active material weight is within the range from 40% to 90% of theoretical working volume ratio.

1 more element

A lithium secondary battery comprising:

a battery case;
and
an internal electrode body contained in the battery case and including a positive electrode, a negative electrode and a separator made of porous polymer, the positive electrode and the negative electrode being wound or laminated so that the positive electrode and negative electrode are not brought into direct contact with each other via the separator,
wherein the minimum value of the working volume ratio of each positive and negative active material is regarded as an experimental safe working volume ratio X3 when the usage rate of the negative electrode is 100%, and
electrode areas of the positive and negative electrodes are divided into n elements respectively, yielding a ratio of the average value of working volume weight of the positive and negative active materials at the element to be regarded as an average working volume ratio Xav while the working volume ratio of the positive and negative active materials constitutes a normal distribution of dispersion σ,
and the faulty rate of batteries using the elements is expressed with an upper probability Q(u) (where u=(X3−Xav)/σ) of the normal distribution, then,
nxQ(u) being the faulty rate of the lithium secondary battery is set to be 1 ppm or less.

4 more elements

Dependencies are inferred from the claim text.

Lithium secondary battery

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Lithium secondary battery

Life of this patent

Abstract

Claims10