A protective element includes an insulating substrate, a plurality of electrodes provided on the insulating substrate, a fuse element electrically connected to any electrode of the plurality of electrodes, and a heat generation element provided on the insulating substrate for heating and fusing the fuse element. The fuse element contains a composite metal material in which a first fusible metal and a second fusible metal are stacked, some of a component of the first fusible metal being dissolved at a joint working temperature, the second fusible metal being lower in melt temperature than the first fusible metal, at least some of a component of the second fusible metal being molten at the joint working temperature.

A fuse assembly includes a housing and a wound wire operable as a fusible element. The housing has a cavity for the fusible element. The fusible element is formed by coating a wire with enamel and wrapping the wire around a core to produce enamel-coated wound wire. The enamel-coated wound wire is attached to the housing. The core is etched away until the core is dissolved and the enamel is stripped away.

A fuse assembly includes a housing and a wound wire operable as a fusible element. The housing has a cavity for the fusible element. The fusible element is formed by coating a wire with enamel and wrapping the wire around a core to produce enamel-coated wound wire. The enamel-coated wound wire is attached to the housing. The core is etched away until the core is dissolved and the enamel is stripped away.

Provided are trimmed parallel element protection devices. Some protection devices may include a substrate and first and second terminals at opposite ends of the substrate. The protection devices may further include a first fusible and a second fusible element extending between the first and second terminals, wherein at least one of the first and second fusible elements includes a trimmed portion.

A protection element includes a first electrode (1), a second electrode (2) having a spring property, and a fuse element material (3) that is disposed between the first electrode and the second electrode, in which the fuse element material (3) is supported by being interposed between the first electrode (1) and the second electrode (2) in a bent state.

A protection element includes a first electrode (1), a second electrode (2) having a spring property, and a fuse element material (3) that is disposed between the first electrode and the second electrode, in which the fuse element material (3) is supported by being interposed between the first electrode (1) and the second electrode (2) in a bent state.

Provided is a protecting device that can prevent damage of the device by releasing the pressure inside the housing by providing openings in the housing and can secure appropriate insulation. The protecting device includes: a meltable conductor 3; first and second external connection terminals 7, 8 connected to both ends of the meltable conductor 3; and a housing 6 having a lower case 4 and an upper case 5, wherein one end of the first external connection terminal 7 and one end of the second external connection terminal 8 are led out from the housing 6, and the housing is provided with a first opening 24 formed facing a front surface of the first external connection terminal 7 and a second opening 25 formed facing a front surface of the second external connection terminal 8.

A fuse element is a fuse element (1) including a flat plate-shaped blowout section (1e) with no through-hole disposed between a first terminal (20a) and a second terminal (20b), in which a width (1d) of the blowout section (1e) has a length equal to or greater than 80% of a width (2d) of each of joining portions joining the first terminal (20a) and the second terminal (20b) to the blowout section (1e). The width (1d) of the blowout section (1e) is preferably a length equal to or greater than 95% of the width (2d) of each of the joining portions.

A fuse element is a fuse element (1) including a flat plate-shaped blowout section (1e) with no through-hole disposed between a first terminal (20a) and a second terminal (20b), in which a width (1d) of the blowout section (1e) has a length equal to or greater than 80% of a width (2d) of each of joining portions joining the first terminal (20a) and the second terminal (20b) to the blowout section (1e). The width (1d) of the blowout section (1e) is preferably a length equal to or greater than 95% of the width (2d) of each of the joining portions.

A protection element (10) of the present invention has a substrate (11), a first fuse element (12) and a second fuse element (13) connected in series on the substrate (11), a heater (14) connected between the first fuse element (12) and the second fuse element (13), a third upper electrode part (17) connected between the first fuse element (12) and the second fuse element (13) and connected to the heater (14) in series, a first conduction part (18) connected to the third upper electrode part (17) and having a lower resistance value than the heater (14), and a third lower electrode part (19) connected to the first conduction part (18) and configured to be connectable to an external protection circuit.