Provided are a protecting device capable of safely and quickly interrupting a current path by restricting heat absorption to a lower case, and a battery pack using the same. A protecting device includes: a meltable conductor 3; and a housing 6 including a lower case 4 and an upper case 5, the housing being formed by joining the lower case 4 and the upper case 5, and the lower case 4 is provided with a recessed portion 23 having support portions 21 provided at opposing side edges of the recessed portion 23 and hollow portions 22 provided on the side edges substantially orthogonal to the side edges of the recessed portion 23 on which the support portions 21 are provided.

A high-voltage direct-current thermal fuse includes one or more fusible components each having two fusible alloy support arms, a fluxing agent, a fusing cavity, two pins, and an insulation block. Two fusible alloy support arms are arranged opposite, and the fusible component is U-shaped. The fusible component and the fluxing agent are sealed within the fusing cavity. The two pins are respectively connected to the two fusible alloy support arms. The insulation block is arranged between the two fusible alloy support arms and separates the two pins. A volume ratio of the fluxing agent to the fusing cavity is approximately 50% or less, preferably, 10%-50%. The number of the one or more fusible components is at least two, and the at least two fusible components are arranged separately. The thermal fuse can avoid the burst and quickly cut off the current, which provides effective thermal protection for a circuit.

A power fuse includes a housing, first and second conductive terminals extending from the housing, and at least one fatigue resistant fuse element assembly connected between the first and second terminals. The fuse element assembly includes at least a first conductive plate and a second conductive plate respectively connecting the first and second conductive terminals, and a plurality of separately provided wire bonded weak spots interconnecting the first conductive plate and the second conductive plate.

A power fuse includes a housing, first and second conductive terminals extending from the housing, and at least one fatigue resistant fuse element assembly connected between the first and second terminals. The fuse element assembly includes at least a first conductive plate and a second conductive plate respectively connecting the first and second conductive terminals, and a plurality of separately provided wire bonded weak spots interconnecting the first conductive plate and the second conductive plate.

Systems and methods for detecting thermal-mechanical strain fatigue in an electrical fuse fatigue include a controller configured to monitor at least one fuse fatigue parameter over a period of time while the fuse is connected to an energized electrical power system, and based on the monitored at least one fuse fatigue parameter, the controller is further configured to determine at least one of a consumed service life of the fuse element or a service life remaining of the fuse element.

Systems and methods for detecting thermal-mechanical strain fatigue in an electrical fuse fatigue include a controller configured to monitor at least one fuse fatigue parameter over a period of time while the fuse is connected to an energized electrical power system, and based on the monitored at least one fuse fatigue parameter, the controller is further configured to determine at least one of a consumed service life of the fuse element or a service life remaining of the fuse element.

A protective element includes a fuse element, a movable member, a concave member, and a press. The fuse member includes, a first end, a second end, and a cut part positioned between the first end and the second end. The fuse element is energized in a first direction from the first end to the second end. The movable member and the concave member are disposed facing each other such that the cut part is interposed therebetween. The press applies a force to the movable member in a pressing direction in which a distance between the movable member and the concave member shortens. At a temperature at or above a softening temperature of the fuse element, the cut part is cut by the force of the press.

Problem To maintain a low internal resistance value and adjust spring characteristics by using a movable contact made of a multilayered material.

Means for Solving Problem A thermosensitive pellet-type thermal fuse includes, in an interior of a cylindrical case having electrical conductivity, a thermosensitive pellet that melts or softens at a temperature, a strong compression spring configured to press the thermosensitive pellet, an insulating cover closing the cylindrical case, a weak compression spring abutting against the insulating cover, a first lead extending through the insulating cover and including an inner end as a fixed contact, a movable contact electrically connecting to the first lead and the cylindrical case, a sealing resin provided surrounding a portion of the first lead and covering an outer end portion of the insulating cover, and sealing an open end portion of the cylindrical case, and a second lead disposed at one end of the cylindrical case. The movable contact includes a conductive base material and a conductive member covering a predetermined surface of the conductive base material. The conductive member is provided to contact portions with the fixed contact and an inner wall surface of the cylindrical case, and is made of a material having a Young’s modulus and a rigidity different from those of the conductive base material.

An improved surface mount electrical fuse including a first fuse terminal; a second fuse terminal spaced apart from the first fuse terminal; and a fuse element formed from a conductive material, the fuse element having a support bridge for supporting the fuse element, the fuse element electrically connecting the first fuse terminal and the second fuse terminal.

An improved surface mount electrical fuse including a first fuse terminal; a second fuse terminal spaced apart from the first fuse terminal; and a fuse element formed from a conductive material, the fuse element having a support bridge for supporting the fuse element, the fuse element electrically connecting the first fuse terminal and the second fuse terminal.