Protective element with heat energy guiding function

Abstract

The invention discloses a protective element with a heat energy guiding function. The element comprises a main body which is electrically connected with a first lead electrode and a second lead electrode. The main body is coated by using a packaging material. A heat energy guiding part is arranged on the main body. The heat energy guiding part is a continuous lead wire with one end arranged on the first lead electrode and the other end extending outwards and penetrating to the outer side of the packaging material. With the structure, with the heat energy guiding part, hear energy can be conducted into or out of the main body with a thermal conduction manner. Therefore, the failure of timely perception when electronic components fail due to overloading can be avoided, and harm can be prevented.

Description

technical field [0001] The invention relates to a protection element of an electronic product, in particular to a protection element capable of conducting heat energy correctly and rapidly. Background technique [0002] There are many types of passive protection components for electronic products, such as varistors (VDR, Voltage Dependent Resistor) or thermal fuses (TCO, Thermal Cut-Off), etc. Among them, varistors are a kind of transient overvoltage protection resistors. A common varistor is a metal oxide varistor (MOV, Metal Oxide Varistor). Its protection mode is that when the power supply voltage is normal, the varistor is in high impedance mode. When the power supply generates abnormal high voltage, the varistor will Quickly switch to low-impedance mode, let the surge current pass, and use heat to eliminate abnormal energy, thus protecting fragile electronic components or circuits. When the two ends of the varistor receive continuous voltage, it will cause gradual agin...

AI Technical Summary

Problems solved by technology

When the two ends of the varistor receive continuous voltage, it will cause gradual aging, which will cause the varistor to heat slowly and destroy the grain boundary structure of the varistor, resulting in failure. In addition, the large current and large energy generated by the instantaneous surge attack, exceeding the tolerance limit of the varistor, resulting in fire or burst

[0003] In order to avoid the harm caused by the failure of the varistor, a thermal fuse is generally used for protection. The thermal fuse is generally triggered by a low melting point alloy. This method requires an excellent contact between the varistor and the thermal fuse to function in time. However, most failures of varistors are unpredictable, so there is not enough time to transfer heat energy to the thermal fuse, and the varistor cannot be effectively protected. Therefore, a composite component that is closely bonded to the varistor and the thermal fuse has been developed. For example, thermally protected metal oxide varistor (TMOV, Thermal Metal Oxide Varistor), please refer to Figure 1, which is a schematic diagram of an existing thermally protected metal oxide varistor 1, the principle of which is to combine the varistor 2 and the thermal fuse 3 are closely attached to facilitate heat conduction to the low-melting point alloy metal of the thermal fuse. Please refer to Fig. 2 and Fig. 3, which are schematic diagrams of the existing thermal fuse 3 before and after startup. With the help of surface tension and special material 4, the molten low-melting point alloy metal material 5 shrinks into a spherical shape to achieve the purpose of cutting off the current

[0004] In order to make the temperature fuse start quickly, the varistor and the temperature fuse are generally packaged together, and the selected low-melting point alloy metal has a melting point lower than 150 ℃, and in order to avoid melting of the low-melting point alloy metal during the encapsulation process, so It is impossible to use epoxy resin (Epoxy) which is better in moisture protection for encapsulation, because the curing condition of epoxy resin is 150 ℃ and 1.5 hours, and the thermal fuse uses surface tension and special materials to help make the molten state The low-melting-point alloy metal material shrinks into a spherical shape, so it will be affected by gravity, which is related to the placement angle, and it is easy to have residual low-melting-point alloy metal, which may cause leakage hazards. In addition, the lead material in general electronic products is tinned copper wire, but The conductivity of low melting point alloy metal is about 10 to 30% of that of tinned copper wire. Therefore, when passing a continuous large current or an instantaneous surge current, it is easy to cause harm due to the difference in conductivity between the two, so it is not suitable for In order to protect the components, it is necessary to improve

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