A battery comprising: a housing having an accommodating cavity having an opening; a core assembly provided in the accommodating cavity and comprising a jelly-roll and an insulating sheet covering the jelly-roll, wherein the jelly-roll comprises a body portion, and the body portion comprises a top end face and a bottom end face located at two ends of the body portion respectively, and a peripheral face connected to the top end face and the bottom end face, and the insulating sheet covers the peripheral face and the bottom end face; a separator provided in the housing and separates the bottom end face of the jelly-roll from a bottom face of the housing; and a top cover assembly connected to the housing in a sealed manner and closes the opening of the housing, and a glue tape; wherein the top cover assembly is spaced apart from the insulating sheet; and wherein the insulating sheet comprises a circumferentially covering area which covers the peripheral face of the body portion, and a bottom covering area which covers the bottom end face of the body portion, and the separator is provided on a side face of the bottom covering area away from the body portion; and wherein the insulating sheet is provided thereon with a liquid-guiding flow channel which partially guides electrolyte located between the jelly-roll and the insulating sheet to a location between the insulating sheet and the housing; characterized in that an air flow channel is formed between the insulating sheet and the top cover assembly; and wherein the top cover assembly comprises a top cover plate for closing the opening of the housing, and a lower plastic member connected to a lower surface of the top cover plate facing the jelly-roll; a plurality of connection bosses are provided at a peripheral edge of the lower plastic member and extending towards the jelly-roll, wherein the circumferentially covering area is connected to an outer peripheral surface of the plurality of connection bosses; and wherein a top surface of the insulating sheet facing the top cover plate is spaced apart from the lower surface of the top cover plate facing the jelly-roll; and wherein the glue tape is provided on the circumferentially covering area and between the circumferentially covering area and the bottom covering area, so that a cavity for covering the jelly-roll is formed and enclosed by the circumferentially covering area and the bottom covering area, and the glue tape is located outside the cavity; and wherein the liquid-guiding flow channel is a gap where a junction of each covering area is formed. a housing having an accommodating cavity having an opening; a core assembly provided in the accommodating cavity and comprising a jelly-roll and an insulating sheet covering the jelly-roll, wherein the jelly-roll comprises a body portion, and the body portion comprises a top end face and a bottom end face located at two ends of the body portion respectively, and a peripheral face connected to the top end face and the bottom end face, and the insulating sheet covers the peripheral face and the bottom end face; a separator provided in the housing and separates the bottom end face of the jelly-roll from a bottom face of the housing; and a top cover assembly connected to the housing in a sealed manner and closes the opening of the housing, and a glue tape; wherein the top cover assembly is spaced apart from the insulating sheet; and wherein the insulating sheet comprises a circumferentially covering area which covers the peripheral face of the body portion, and a bottom covering area which covers the bottom end face of the body portion, and the separator is provided on a side face of the bottom covering area away from the body portion; and wherein the insulating sheet is provided thereon with a liquid-guiding flow channel which partially guides electrolyte located between the jelly-roll and the insulating sheet to a location between the insulating sheet and the housing; an air flow channel is formed between the insulating sheet and the top cover assembly; and wherein the top cover assembly comprises a top cover plate for closing the opening of the housing, and a lower plastic member connected to a lower surface of the top cover plate facing the jelly-roll; a plurality of connection bosses are provided at a peripheral edge of the lower plastic member and extending towards the jelly-roll, wherein the circumferentially covering area is connected to an outer peripheral surface of the plurality of connection bosses; and wherein a top surface of the insulating sheet facing the top cover plate is spaced apart from the lower surface of the top cover plate facing the jelly-roll; and wherein the glue tape is provided on the circumferentially covering area and between the circumferentially covering area and the bottom covering area, so that a cavity for covering the jelly-roll is formed and enclosed by the circumferentially covering area and the bottom covering area, and the glue tape is located outside the cavity; and wherein the liquid-guiding flow channel is a gap where a junction of each covering area is formed.