A secondary battery comprising: an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; a case accommodating the electrode assembly and having an opening at one side thereof; a cap plate closing the opening of the case and having a first recessed groove at one end thereof and a second recessed groove at another end thereof, both the first and second recessed grooves (310, 320) being at an outer surface of the cap plate; a first terminal unit comprising: a first electrode terminal electrically connected to the first electrode plate and protruding outside of the case; a first terminal plate electrically connected to the first electrode terminal; and an insulation member coupled to the cap plate in the first recessed groove and surrounding peripheral surfaces and a bottom surface of the first terminal plate; and a second terminal unit electrically connected to the second electrode plate and coupled to the cap plate in the second recessed groove, wherein the second terminal unit comprises: a second electrode terminal electrically connected to the second electrode plate and extending through the cap plate to protrude outside of the case; a second terminal plate electrically connected to the second electrode terminal; and a top plate coupled to the cap plate in the second recessed groove and contacting a bottom surface of the second terminal plate and peripheral surfaces and a bottom surface of the second recessed groove, and wherein the flow of current I is distributed in two directions, i.e. parallel and perpendicular to the cap plate, through the top plate. an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; a case accommodating the electrode assembly and having an opening at one side thereof; a cap plate closing the opening of the case and having a first recessed groove at one end thereof and a second recessed groove at another end thereof, both the first and second recessed grooves (310, 320) being at an outer surface of the cap plate; a first terminal unit comprising: a first electrode terminal electrically connected to the first electrode plate and protruding outside of the case; a first terminal plate electrically connected to the first electrode terminal; and an insulation member coupled to the cap plate in the first recessed groove and surrounding peripheral surfaces and a bottom surface of the first terminal plate; and a first electrode terminal electrically connected to the first electrode plate and protruding outside of the case; a first terminal plate electrically connected to the first electrode terminal; and an insulation member coupled to the cap plate in the first recessed groove and surrounding peripheral surfaces and a bottom surface of the first terminal plate; and a second terminal unit electrically connected to the second electrode plate and coupled to the cap plate in the second recessed groove, wherein the second terminal unit comprises: a second electrode terminal electrically connected to the second electrode plate and extending through the cap plate to protrude outside of the case; a second terminal plate electrically connected to the second electrode terminal; and a top plate coupled to the cap plate in the second recessed groove and contacting a bottom surface of the second terminal plate and peripheral surfaces and a bottom surface of the second recessed groove, and wherein the flow of current I is distributed in two directions, i.e. parallel and perpendicular to the cap plate, through the top plate. a second electrode terminal electrically connected to the second electrode plate and extending through the cap plate to protrude outside of the case; a second terminal plate electrically connected to the second electrode terminal; and a top plate coupled to the cap plate in the second recessed groove and contacting a bottom surface of the second terminal plate and peripheral surfaces and a bottom surface of the second recessed groove, and wherein the flow of current I is distributed in two directions, i.e. parallel and perpendicular to the cap plate, through the top plate.