Over-current protection device and method of making the same

An over-current protection device;

• comprising:
• at least one PTC device of a thickness less than 0.4 mm, the PTC device comprising a first electrically conductive member, a second electrically conductive member and a PTC material layer laminated between the first and second electrically conductive members;
• a first electrode electrically connected to the first electrically conductive member;
• a second electrode electrically connected to the second electrically conductive member;
• a first insulating layer disposed on the first electrically conductive member and having a thickness between 10 μm and 65 μm;
• and
• a second insulating layer disposed on the second electrically conductive member, the second insulating layer having a thickness between 10 μm and 65 μm;
• wherein the over-current protection device is a stacked structure in which the first insulating layer is an intermediate layer laminated between the PTC device and the first and second electrodes at a side of the PTC device, and the second insulating layer is another intermediate layer laminated between the PTC device and the first and second electrodes at another side of the PTC device;
• wherein the over-current protection device extends along a first direction;
• and comprises at least one hole extending along a second direction substantially perpendicular to the first direction, the hole is in direct contact with lateral surfaces of the first and second insulating layers such that a space of the hole is capable of accommodating resin flow generated from the first and second insulating layers during manufacturing, a value of a covered area of the hole divided by an area of the form factor of the over-current protection device is equal to or greater than 2%, and a value of the thickness of the over-current protection device divided by the number of the PTC devices is less than 0.7 mm.