Thermal cutoff

A thermal cutoff, comprising:

• a current-carrying fusible element;
• a first lead wire;
• a second lead wire;
• a closed cavity;
• and
• a high-voltage fusible element;
• wherein,
• two ends of the current-carrying fusible element are connected to a first electrode plate and a second electrode plate, respectively;
• the closed cavity is bounded by a housing, a cover plate, and a sealant;
• the current-carrying fusible element is provided in the closed cavity, wherein one end of the housing is provided with an opening;
• each of the first lead wire and the second lead wire is wrapped by an insulating sheath;
• one end of the first lead wire and one end of the second lead wire are electrically connected to the first electrode plate and the second electrode plate, respectively;
• the sealant is filled in the opening of the housing;
• the sealant at least covers an electrical joint between the first lead wire and the first electrode plate and an end of the first lead wire;
• and
• the sealant also covers an electrical joint between the second electrode plate and the second lead wire and an end of the second lead wire;
• the high-voltage fusible element is arranged in parallel with the current-carrying fusible element;
• the high-voltage fusible element is also provided in the closed cavity;
• the current-carrying fusible element comprises a current carrier;
• the high-voltage fusible element comprises a fuse link;
• a melting point of the current carrier is lower than a melting point of the fuse link;
• and
• an internal resistance value of the current carrier is lower than an internal resistance value of the fuse link;
• the housing has a first cavity and a second cavity side-by-side;
• the current carrier and the fuse link are arranged in parallel in the first cavity and the second cavity, respectively;
• the first cavity is further filled with a first fusing agent contacting and wrapping the current carrier;
• the second cavity is further filled with an arc extinguishing medium or a second fusing agent contacting and wrapping the fuse link;
• each electrode plate of the first electrode plate and the second electrode plate is a substantially L-shaped structure, and
• the each electrode plate is provided with a slot to divide one end of the each electrode plate into two terminals to be connected to one end of the current carrier and one end of the fuse link, respectively.