Lithium secondary battery

Abstract

A lithium secondary battery having enhanced safety, which includes an electrode group, a non-aqueous electrolyte and a battery can for housing them. The electrode group includes: a positive electrode having a strip-shaped positive electrode current collector and a material mixture layer carried thereon; a negative electrode having a strip-shaped negative electrode current collector and a material mixture layer carried thereon; a separator; and a porous heat resistant layer. The positive and negative electrodes are spirally wound with the separator and the porous heat resistant layer interposed therebetween. An outermost surface of the electrode group includes an exposed portion of either of the positive and negative electrode current collectors. The exposed portion faces an inner surface of the battery can with the separator interposed therebetween, and has opposite polarity to that of the battery can.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a schematic partial cross-sectional view of a lithium secondary battery according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a lithium secondary battery according to a second embodiment of the present invention.

FIG. 3 is a partially cut-away perspective view of a prismatic battery according to EXAMPLE of the present invention.

Claims

1. A lithium secondary battery comprising an electrode group, a non-aqueous electrolyte and a battery can for housing said electrode group and said non-aqueous electrolyte, said electrode group comprising: a positive electrode comprising a strip-shaped positive electrode current collector and a positive electrode material mixture layer carried on said positive electrode current collector; a negative electrode comprising a strip-shaped negative electrode current collector and a negative electrode material mixture layer carried on said negative electrode current collector; a separator; and a porous heat resistant layer,said positive electrode and said negative electrode being spirally wound with said separator and said porous heat resistant layer interposed therebetween,wherein an outermost surface of said electrode group comprises an exposed portion of either of said positive electrode current collector and said negative electrode current collector, andsaid exposed portion faces an inner surface of said battery can with said separator interposed therebetween, and has opposite polarity to that of said battery can.

2. The lithium ion secondary battery in accordance with claim 1, wherein said battery can comprises aluminum and is electrically connected to said positive electrode, andsaid exposed portion is an exposed portion of said negative electrode current collector.

3. A lithium secondary battery comprising an electrode group, a non-aqueous electrolyte and a battery case for housing said electrode group and said non-aqueous electrolyte, said electrode group comprising: a positive electrode comprising a strip-shaped positive electrode current collector and a positive electrode material mixture layer carried on said positive electrode current collector; a negative electrode comprising a strip-shaped negative electrode current collector and a negative electrode material mixture layer carried on said negative electrode current collector; a separator; and a porous heat resistant layer,said positive electrode and said negative electrode being spirally wound with said separator and said porous heat resistant layer interposed therebetween,wherein said battery case comprises: a first battery can for housing said electrode group; and a second battery can for housing said first battery can,an insulating layer is disposed between said first battery can and said second battery can, andone of said positive electrode and said negative electrode is electrically connected to said first battery can, and the other electrode is electrically connected to said second battery can.