Abstract: A battery tray for storing a battery comprises: a battery storage unit comprising: a first side and a second side facing each other, and a third side and a fourth side facing each other, wherein the third and fourth sides have planar portions for accommodating a prismatic battery cell and round portions for accommodating a cylindrical battery cell; a first guiding unit extending from a lower portion of the third side to secure a first end of a prismatic battery cell; and a second guiding unit extending from a lower portion of the fourth side to secure a second end of a prismatic battery cell.

Abstract: A secondary battery which can prevent leakage of an electrolytic solution by improving the sealing property of an electrolytic solution injection hole formed at a cap plate comprises: an electrode assembly including a cathode plate, a separator and an anode plate; a can having an upper opening for receiving the electrode assembly; and a cap assembly which is combined with the upper opening of the can, and which includes a cap plate provided with an electrolytic solution injection hole at one side thereof. A groove is formed in an axial direction on an inner circumferential surface of the electrolytic solution injection hole. Thus, the contact area between a stopper and the electrolytic solution injection hole is increased, thereby improving the sealing property of the electrolytic solution injection hole.

Abstract: A secondary battery which can prevent leakage of an electrolytic solution by improving the sealing property of an electrolytic solution injection hole formed at a cap plate comprises: an electrode assembly including a cathode plate, a separator and an anode plate; a can having an upper opening for receiving the electrode assembly; and a cap assembly which is combined with the upper opening of the can, and which includes a cap plate provided with an electrolytic solution injection hole at one side thereof. A groove is formed in an axial direction on an inner circumferential surface of the electrolytic solution injection hole. Thus, the contact area between a stopper and the electrolytic solution injection hole is increased, thereby improving the sealing property of the electrolytic solution injection hole.

Abstract: A secondary battery includes an electrode assembly including: a winding having a positive electrode plate, a negative electrodes plate, and stacked together with a separator interposed between the positive and negative electrode plate; a can having an opening portion to receive the electrode assembly; a cap assembly including a cap plate to close the opening portion of the can, the cap plate having an electrolyte injection hole arranged therein; and a first extension groove having a greater diameter than that of the electrolyte injection hole, the first extension groove being arranged in an entering portion of the electrolyte injection hole and having at least one hollow portion arranged on the surface of the first extension groove.