Electrode assembly, battery, and battery pack and vehicle including the same

An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis in a winding direction to define a core and an outer circumference of the electrode assembly,

• wherein the first electrode includes a first active material portion coated with an active material layer and a first uncoated portion not coated with an active material layer along the winding direction,
• wherein the first uncoated portion includes a segment region divided into a plurality of independently bendable segments by a plurality of cut grooves provided along the winding direction,
• wherein the segment region includes a plurality of segment groups arranged with a group separation interval along the winding direction,
• wherein one end of the electrode assembly includes a plurality of segment alignments in which the plurality of segment groups are aligned along a radial direction of the electrode assembly, and an electrolyte impregnation portion provided between adjacent segment alignments in a circumferential direction of the electrode assembly,
• wherein an end of the first active material portion is exposed between winding turns of the separator,
• wherein the segments included in each segment alignment are bent toward the core to form a bending surface region,
• wherein an end of the separator is spaced apart from a criterion line extending in the winding direction along a location corresponding to the plurality of cut grooves by a preset distance or less, and
• wherein the preset distance is 30% of a minimum height of the segments forming the bending surface region.

A battery, comprising:

• an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis in a winding direction to define a core and an outer circumference of the electrode assembly, the first electrode including a first active material portion coated with an active material layer and a first uncoated portion not coated with an active material layer along the winding direction, the first uncoated portion including a segment region divided into a plurality of independently bendable segments by a plurality of cut grooves provided along the winding direction, the segment region including a plurality of segment groups arranged with a group separation interval along the winding direction, one end of the electrode assembly including a plurality of segment alignments in which the plurality of segment groups are aligned along a radial direction of the electrode assembly, an electrolyte impregnation portion being provided between adjacent segment alignments in a circumferential direction of the electrode assembly, an end of the first active material portion being exposed between winding turns of the separator, the segments included in each segment alignment being bent toward the core to form a bending surface region, an end of the separator being spaced apart from a criterion line extending along the winding direction along a location corresponding to the plurality of cut grooves by a preset distance or less, and the preset distance being 30% of a minimum height of the segments forming the bending surface region;
• a battery housing configured to accommodate the electrode assembly and electrically connected to one of the first electrode and the second electrode to have a first polarity;
• a sealing body configured to seal an open end of the battery housing;
• and
• a terminal having a surface exposed to outside the battery housing and electrically connected to another of the first electrode and the second electrode to have a second polarity.