Secondary battery and battery module

A battery module, comprising secondary batteries arranged sequentially;

• each secondary battery comprising an electrode assembly, a case and a cap assembly;
• the case having an accommodating cavity, the accommodating cavity having an opening, and the electrode assembly being accommodated in the accommodating cavity;
• the electrode assembly comprising electrode units, and the electrode units being stacked in an axial direction of the accommodating cavity;
• the cap assembly comprising a cap plate and a vent piece, the cap plate having a length and a width, the cap plate being connected with the case and positioned at a side of the electrode assembly in the axial direction;
• the cap plate being provided with a through-hole at a central region of the cap plate in a length direction of the cap plate, the through-hole overlapping a middle point of the cap plate in the length direction, the through-hole having a shape with a maximum spacing oriented along a width direction of the cap plate, the vent piece being connected with the cap plate and covering the through-hole;
• the cap plate having a first inner surface at a side close to the electrode assembly, the vent piece having a second inner surface at a side close to the electrode assembly, and the second inner surface being positioned at a side of the first inner surface away from the electrode assembly;
• an arrange direction of the secondary batteries being perpendicular to the axial direction;
• and
• the cap assembly further comprising a protecting piece, and the protecting piece being mounted to a top surface of the cap plate from outside and covering the through-hole, and the vent piece being connected to a bottom surface of the cap plate positioned at the side of the first inner surface away from the electrode assembly.

An electric vehicle, comprising a battery module, the battery module comprising secondary batteries arranged sequentially;

• each secondary battery comprising an electrode assembly, a case and a cap assembly;
• the case having an accommodating cavity, the accommodating cavity having an opening, and the electrode assembly being accommodated in the accommodating cavity;
• the electrode assembly comprising electrode units, and the electrode units being stacked in an axial direction of the accommodating cavity;
• the cap assembly comprising a cap plate and a vent piece, the cap plate having a length and a width, being connected with the case and positioned at a side of the electrode assembly in the axial direction;
• the cap plate being provided with a through-hole at a central region of the cap plate in a length direction of the cap plate, the through-hole overlapping a middle point of the cap plate in the length direction, the through-hole having a shape with a maximum spacing oriented along a width direction of the cap plate, the vent piece being connected with the cap plate and covering the through-hole;
• the cap plate having a first inner surface at a side close to the electrode assembly, the vent piece having a second inner surface at a side close to the electrode assembly, and the second inner surface being positioned at a side of the first inner surface away from the electrode assembly;
• an arrange direction of the secondary batteries being perpendicular to the axial direction;
• and
• the cap assembly further comprising a protecting piece, and the protecting piece being mounted to a top surface of the cap plate from outside and covering the through-hole, and the vent piece being connected to a bottom surface of the cap plate positioned at the side of the first inner surface away from the electrode assembly.