A rechargeable battery, comprising: a plurality of electrode assemblies; a case accommodating the plurality of electrode assemblies, the case having an opening; a cap assembly including a cap plate coupled to the opening to seal the case; one or more electrode terminals (21, 22) electrically connected to the electrode assemblies; and a lower insulating member adjacent one or more electrode terminals and installed in the case, wherein: the lower insulating member includes: a first portion adjacent an electrode terminal, the first portion having a first width in a direction parallel to the cap plate and being fixed to the electrode terminal, and a second portion extending from one end of the first portion, the second portion having a second width in the direction parallel to the cap plate and perpendicular to the direction of extension of the first portion, and a width-direction end of the second portion lies in a plane between an inner surface of the case and centre (C1, C2) of a top surface of an outermost electrode assembly among the electrode assemblies, the top surface facing the second portion, wherein the second width of the second portion is larger than the first width. a plurality of electrode assemblies; a case accommodating the plurality of electrode assemblies, the case having an opening; a cap assembly including a cap plate coupled to the opening to seal the case; one or more electrode terminals (21, 22) electrically connected to the electrode assemblies; and a lower insulating member adjacent one or more electrode terminals and installed in the case, wherein: the lower insulating member includes: a first portion adjacent an electrode terminal, the first portion having a first width in a direction parallel to the cap plate and being fixed to the electrode terminal, and a second portion extending from one end of the first portion, the second portion having a second width in the direction parallel to the cap plate and perpendicular to the direction of extension of the first portion, and a width-direction end of the second portion lies in a plane between an inner surface of the case and centre (C1, C2) of a top surface of an outermost electrode assembly among the electrode assemblies, the top surface facing the second portion, wherein the second width of the second portion is larger than the first width. the lower insulating member includes: a first portion adjacent an electrode terminal, the first portion having a first width in a direction parallel to the cap plate and being fixed to the electrode terminal, and a second portion extending from one end of the first portion, the second portion having a second width in the direction parallel to the cap plate and perpendicular to the direction of extension of the first portion, and a first portion adjacent an electrode terminal, the first portion having a first width in a direction parallel to the cap plate and being fixed to the electrode terminal, and a second portion extending from one end of the first portion, the second portion having a second width in the direction parallel to the cap plate and perpendicular to the direction of extension of the first portion, and a width-direction end of the second portion lies in a plane between an inner surface of the case and centre (C1, C2) of a top surface of an outermost electrode assembly among the electrode assemblies, the top surface facing the second portion, wherein the second width of the second portion is larger than the first width.