SECONDARY BATTERY

摘要

A secondary battery typified by a lithium-ion secondary battery includes a battery outer container in which a gas release valve and positive and negative electrode external terminals are provided, an electrode group in which positive and negative plates are stacked with a separator interposed therebetween and current collection portions are provided at both ends, and positive and negative electrode current collectors forming a current path from the current collection portions of the electrode group to the positive and negative electrode external terminals, and the cross-sectional area of a gas exhaust flow channel through which gas generated inside the electrode group is discharged from the gas release valve is set so as to increase in a downstream direction.

主权项

1. A secondary battery comprising:
a battery outer container; and a wound electrode group that is located within the battery outer container; wherein the wound electrode group is formed by winding a thin electrode group along a winding axis; wherein the thin electrode group includes one or more belt-like positive plates that are alternately stacked with one or more belt-like negative plates with one of one or more belt-like separators interposed there between; wherein the wound electrode group includes: a front and a back planar portions, a first side portion perpendicular to the winding axis and separated along the winding axis from a second side portion that is parallel to the first side, a first curved portion parallel to the winding axis, a second curved portion separated along an axis perpendicular to the winding axis that is parallel to the first curved portion, a first compressed region along the first side portion that forms a negative electrode, a second compressed region along the second side portion that forms a positive electrode, a positive current collector forming a positive current path from the positive electrode to a positive electrode external electrode; and a negative current collector forming a negative current path from the negative electrode to a negative electrode external electrode; wherein battery outer container includes: the positive external electrode, the negative external electrode, a battery case, and a battery cover, wherein the battery cover seals an opening of the battery case and includes a gas release valve that has a cross sectional area S3; wherein the first side portion of the wound electrode group is proximate to a first side of the battery case and forms a first flow channel between the first side of the battery case and the first side portion of the wound electrode group, wherein the first flow channel has a cross sectional area B1; wherein the second side portion of the wound electrode group is proximate to a second side of the battery case and forms a second flow channel between the second side of the battery case and the second side portion of the wound electrode group, wherein the second flow channel has a cross sectional area B2; wherein the first curved portion of the wound electrode group is proximate to the battery cover and forms a third flow channel between the battery cover and the first curved portion, wherein the third flow channel has a cross sectional area S2; and wherein S3 is larger than a minimum of B1, B2 and S2.