Electric storage device

A lithium-ion secondary battery comprising:

• a case;
• a sheet-like positive electrode disposed within the case;
• a sheet-like negative electrode disposed within the case, wherein a polarity of the negative electrode is different from that of the positive electrode;
• a separator insulating the positive electrode from the negative electrode;
• a positive electrode terminal and a negative electrode terminal provided on the case;
• a first conductive path from the positive electrode terminal to the positive electrode;
• a second conductive path from the negative electrode terminal to the negative electrode;
• and
• a current interruption device disposed between the negative electrode terminal and the negative electrode in the case, the current interruption device being configured to interrupt the second conductive path, wherein
• one surface of the positive electrode faces one surface of the negative electrode,
• the separator includes:
• a first surface part covering the one surface of the positive electrode, a second surface part covering the other surface of the positive electrode, and a connection part connected to both the first surface part and the second surface part,
• the connection part is disposed between the current interruption device and an end of the positive electrode on a current interruption device side,
• the connection part contacts a surface of the current interruption device, and
• the negative electrode covers the positive electrode, and is larger than the positive electrode.