Top cover assembly of secondary battery and secondary battery

A top cover assembly of a secondary battery, comprising:

• a first electrode terminal, a conduction member, a second electrode terminal, and a top cover plate,
• wherein the top cover plate is insulated from the first electrode terminal, and the top cover plate is electrically connected to the second electrode terminal,
• wherein the secondary battery further comprises a contact plate, and the contact plate is attached to the top cover plate, and the conduction member is insulated from the top cover plate,
• wherein the conduction member comprises an electrode terminal connection portion, a first fuse member, and a contact plate connection portion, wherein the electrode terminal connection portion is electrically connected to the first electrode terminal, the first fuse member is electrically connected between the electrode terminal connection portion and the contact plate connection portion, and a melting point of the first fuse member is lower than a melting point of the electrode terminal connection portion and a melting point of the contact plate connection portion,
• wherein the contact plate is configured to deform under an internal pressure of the secondary battery and to be electrically connected to the contact plate connection portion when the internal pressure of the secondary battery exceeds a reference pressure, for forming an electric connection path passing through the first electrode terminal and the second electrode terminal, and
• wherein the conduction member further comprises a connection layer, wherein the first fuse member is electrically connected to the electrode terminal connection portion via the connection layer, and the connection layer is configured to enhance a connection strength between the first fuse and the electrode terminal connection portion;
• and/or the first fuse member is electrically connected to the contact plate connection portion via the connection layer, and the connection layer is configured to enhance a connection strength between the first fuse and the contact plate connection portion.