The invention relates to a thermally triggerable indication or switching device, having a movable, mechanically preloaded slide which directly or indirectly triggers or actuates the indication or switching device, and having a preformed part which changes its state of aggregation under the effect of heat, the preformed part, in the functional state, being adapted to be arranged so as to block the movable slide. According to the invention, in the initial state, the preformed part is loosely located in a receiving space. For transferring the preformed part to the functional state, the slide is moved in a position such that a gap space opens between the slide and a slide stop, wherein the preformed part enters the gap space and the slide is simultaneously preloaded.

A thermal cutoff at least includes a current-carrying fusible element having two ends connected to a first electrode and a second electrode. The current-carrying fusible element is provided in a closed cavity bounded by a housing having an opening at one end, a cover plate, and a sealant. The thermal cutoff further includes a first lead wire and a second lead wire each wrapped by an insulating sheath. One end of the first lead wire and one end of the second lead wire are electrically connected to the first electrode and the second electrode. The sealant is filled in the opening of the housing, covers an electrical joint between the first lead wire and a first electrode plate and an end of the first lead wire, and also covers an electrical joint between a second electrode plate and the second lead wire and an end of the second lead wire.

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 protective element (30) includes an insulating substrate (33), a plurality of electrodes (34) provided on the insulating substrate (33), a fuse element (35) electrically connected to any electrode (34) of the plurality of electrodes (34), and a heat generation element (38) provided on the insulating substrate (33) for heating and fusing the fuse element (35). The fuse element (35) contains a composite metal material in which a first fusible metal (31) and a second fusible metal (32) are stacked, some of a component of the first fusible metal (31) being dissolved at a joint working temperature, the second fusible metal (32) being lower in melt temperature than the first fusible metal (31), at least some of a component of the second fusible metal (32) being molten at the joint working temperature.

A fuse element includes: a low-melting-point metal layer; a high-melting-point metal layer provided over at least one surface of the low-melting-point metal layer; and an intermediate layer disposed between the low-melting-point metal layer and the high-melting-point metal layer. Each of the high-melting-point metal layer and the intermediate layer is made of a metal that is liquefied by contacting a molten form of the low-melting-point metal layer. The high-melting point metal layer is made of silver or an alloy comprising silver as a main component thereof. A melting point of a material constituting the intermediate layer is higher than a melting point of a material constituting the low-melting-point metal layer and lower than a melting point of a material constituting the high-melting-point metal layer.

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.

To provide a protection element and a protection circuit that can protect from an overcurrent without using rectifying means such as a diode or a switching element, and can more reliably interrupt passage of an electric current during operation with a simpler circuit configuration. A protection element including: an insulating substrate; at least a pair of fuse electrodes provided on the insulating substrate; an intermediate electrode provided on the insulating substrate between the fuse electrodes; a fuse element joined to the fuse electrodes and the intermediate electrode, and electrically connected to the fuse electrodes and the intermediate electrode; and a heating element provided on the insulating substrate to be electrically connected to the intermediate electrode and a heating electrode, wherein conduction means between at least a pair of electrodes of the fuse electrodes including the intermediate electrode is provided differently from conduction means between the other electrodes.

An electronic module for a power tool having an electric motor is provided including a printed circuit board (PCB), an inverter bridge circuit, a first conductive track disposed on the PCB and coupled to the power source, a second conductive track disposed on the PCB and coupled to the inverter bridge circuit, and a fuse strap provided between the first conductive track and the second conductive track. The fuse strap includes a main body spaced apart from the PCB, a first mounting portion mounted on the first conductive track via a first solder joint, and a second mounting portion mounted on the second conductive track via a second solder joint.

Embodiments described herein relate generally to a current interrupt device (CID) including a frangible bulb that is configured to be thermally triggered. In some embodiments, the CID includes a breaking contact electrically coupled to a fixed contact and held in electrical contact by the frangible bulb. In some embodiments, the frangible bulb is configured to break at a temperature threshold. In some embodiments, the breaking contact is configured to bend, rotate and/or otherwise deform about a hinge point in order to become electrically disconnected from the fixed contact when the frangible bulb breaks. In some embodiments, opening the electrical circuit between the breaking contact and the fixed contact may prevent overcharging, overvoltage conditions, overcurrent conditions, thermal runaway, and/or other catastrophic failure events.

A varistor component and a method for securing a varistor component are disclosed. In an embodiment a varistor component includes a first external contact, a second external contact, a varistor electrically connected to the first external contact, a path between the varistor and the second external contact and an active releasing device having a shutter and a heat sensitive element, wherein, under abnormal operation conditions, the heat sensitive element releases the shutter, and the shutter moves along a straight line and closes the path between the varistor and the second external contact.