Lithium secondary battery with safety device

A lithium secondary battery comprising:

• a generation element which generates electrical power;
• a can which houses the generation element and which has a first surface and a second surface, the first surface comprising a first terminal electrically connected to the generation element and the second surface comprising a second terminal electrically connected to the generation element;
• a safety vent formed in the first surface of the can;
• a first plate welded to the first surface of the can and positioned to protect the safety vent;
• a safety device;
• and
• a lead unit which electrically connects the first terminal and the second terminal through the safety device and having a lead plate with one end disposed between the first surface and the first plate and welded directly to the first surface, and another end connected directly to the safety device,
• wherein the first plate includes a weld portion welded to the first surface, and an accommodating portion accommodating the one end of the lead plate between the accommodating portion and the first surface and directly contacting the one end of the lead plate, and
• wherein the accommodating portion has a bent portion that extends from the weld portion to form a gap between the first surface and the bent portion such that the lead plate fits in the gap between the first surface and the accommodating portion.

A lithium secondary battery comprising:

• a generation element which generates electrical power;
• a can which houses the generation element and which has a first surface and a second surface, the first surface comprising a first terminal electrically connected to the generation element, and the second surface comprising a second terminal electrically connected to the generation element;
• a safety vent formed in the first surface of the can;
• a first plate attached to the first surface of the can and positioned to protect the safety vent;
• a safety device;
• and
• a lead unit which electrically connects the first terminal and the second terminal through the safety device and having a lead plate with one end welded directly to the first surface and another end directly connected to the safety device
• wherein the can comprises a first material, and
• the lead plate comprises:
• a first layer disposed adjacent the can which comprises the first material, and
• a second layer comprising a second material other than the first material.