A secondary battery comprising: an electrode assembly comprising a top surface, a bottom surface and two side surfaces; a cap assembly including a cap plate sealing a top opening of the case and an electrode terminal (520, 530) penetrating the cap plate;a collector plate (200, 300) electrically connected to the electrode assembly and comprising: a terminal connecting portion (210, 310) located between an upper portion of the electrode assembly and a lower portion of the cap assembly; a top surface support portion (220, 320) located at one side of the terminal connecting portion and facing the top surface of the electrode assembly; a side surface support portion (250, 350) facing one of the side surfaces of the electrode assembly; and a bottom surface support portion (240, 340) facing the bottom surface of the electrode assembly; and a case surrounding the electrode assembly and the collector plate; characterised in that: the collector plate (200, 300) further comprises a plurality of connecting portions (230, 330) extending between the top surface support portion (220, 320) and the bottom surface support portion (240, 340) from opposing sides of the terminal connecting portion (210, 310), wherein at least a part of the side surface support portion (250, 350) is wedge shaped and protrudes from the first connecting portions (230, 330) between a plurality of electrode uncoated portions of the electrode assembly. an electrode assembly comprising a top surface, a bottom surface and two side surfaces; a cap assembly including a cap plate sealing a top opening of the case and an electrode terminal (520, 530) penetrating the cap plate;a collector plate (200, 300) electrically connected to the electrode assembly and comprising: a terminal connecting portion (210, 310) located between an upper portion of the electrode assembly and a lower portion of the cap assembly; a top surface support portion (220, 320) located at one side of the terminal connecting portion and facing the top surface of the electrode assembly; a side surface support portion (250, 350) facing one of the side surfaces of the electrode assembly; and a bottom surface support portion (240, 340) facing the bottom surface of the electrode assembly; and a terminal connecting portion (210, 310) located between an upper portion of the electrode assembly and a lower portion of the cap assembly; a top surface support portion (220, 320) located at one side of the terminal connecting portion and facing the top surface of the electrode assembly; a side surface support portion (250, 350) facing one of the side surfaces of the electrode assembly; and a bottom surface support portion (240, 340) facing the bottom surface of the electrode assembly; and a case surrounding the electrode assembly and the collector plate; the collector plate (200, 300) further comprises a plurality of connecting portions (230, 330) extending between the top surface support portion (220, 320) and the bottom surface support portion (240, 340) from opposing sides of the terminal connecting portion (210, 310), wherein at least a part of the side surface support portion (250, 350) is wedge shaped and protrudes from the first connecting portions (230, 330) between a plurality of electrode uncoated portions of the electrode assembly.