CN108987204B - Protection element and circuit protection device thereof - Google Patents

Abstract

The invention provides a protection element and a circuit protection device thereof. The protection element comprises a first planar substrate, a second planar substrate, a heating element, a fuse element and an adsorption element. The first planar substrate includes a first surface, and the second planar substrate includes a second surface facing the first surface. The heating member is disposed on the first surface, and the fuse is disposed above the heating member. The adsorption piece is arranged on the second surface and is positioned above the fuse piece. When overvoltage or overtemperature occurs, the heating element generates heat to melt the fuse element, and the adsorption element adsorbs the molten metal of the fuse element.

Description

protection element and circuit protection device thereof

Technical Field

The present invention relates to a protection device for an electronic device and a circuit protection device including the same, and more particularly, to a protection device and a circuit protection device having a function of preventing an overvoltage, an overcurrent, or an overtemperature.

Background

As a conventional protection element for cutting off an overcurrent, a current fuse (fuse) composed of a low melting point metal body such as lead, tin, or antimony is widely known. Then, in order to prevent overcurrent and overvoltage, a protective element including a heat generating layer and a low melting point metal layer laminated in this order on one planar substrate has been continuously developed. When overvoltage occurs, the heating body generates heat, the heat is transferred upwards from the bottom, the electrode bearing the low-melting-point metal body is heated, the low-melting-point metal body is fused, and flowing current is cut off, so that related circuits or electronic devices are protected.

In recent years, mobile devices have become very popular, and information products such as mobile phones, computers, personal mobile assistants, etc. are seen everywhere, so that the dependence of people on information products is increasing. However, news about explosion of batteries of portable electronic products such as mobile phones during charging and discharging is presented from time to time. Therefore, manufacturers gradually improve the design of the over-current and over-voltage protection devices, and enhance the protection measures of the battery during charging and discharging to prevent the battery from exploding due to over-voltage or over-current during charging and discharging.

The protection method of the protection device proposed in the prior art is to connect the fuse in the protection device in series with the circuit of the battery, and to electrically connect the low melting point metal layer and the heat generating layer in the protection device to the switch (switch) and the Integrated Circuit (IC) device. Therefore, when the IC component measures the overvoltage, the switch is started to be conducted, so that the current passes through the heating layer in the protection component, the heating layer generates heat to fuse the fuse, and the circuit of the battery is in an open circuit state to achieve the overvoltage protection. It is well known to those skilled in the art that when an overcurrent occurs, a large amount of current flows through the fuse to cause the fuse to generate heat and blow, thereby achieving the overcurrent protection.

Fig. 1 is a schematic cross-sectional view of a conventional protection device, which implements the protection mechanism. The protection device 100 includes a planar substrate 110, a heating member 120, an insulating layer 130, a low-melting-point metal layer 140, a flux 150, and a cover 170. The outer edge of the housing 170 is disposed on the surface of the planar substrate 110, and provides an inner space for accommodating the heating element 120, the insulating layer 130, the low melting point metal layer 140 and the flux 150. The heater 120 is disposed on the planar substrate 110 and electrically connected to the two heater electrodes 125. The low melting point metal layer 140 connects the electrode layers 160 on both sides and one intermediate electrode 165. An insulating layer 130 covers the heater 120 and the heater electrodes 125. The low melting point metal layer 140 is disposed above the insulating layer 130 as a fuse, and the flux 150 completely covers the low melting point metal layer 140. In this way, when the heating element 120 generates heat, the low melting point metal layer 140 can be directly melted, so that the low melting point metal layer 140 is melted and flows to the electrode layers 160 and the middle electrode 165 on both sides, and therefore, the three electrode blocks of the electrode layers 160 and the middle electrode 165 on both sides are collected after the low melting point metal layer 140 is melted, so that the low melting point metal layer 140 is separated into three blocks from the original whole metal after being melted, and the current is cut off to achieve the protection purpose. In the prior art, since all three electrode blocks are below the low melting point metal layer 140, but the chemical protective film such as rosin is exposed to the air above the low melting point metal layer 140, even if the chemical protective film is present, the chemical protective film loses its protective effect due to loss or volatilization under high temperature heating, so that the surface of the low melting point metal layer 140 is easily oxidized to different degrees during high temperature heating and melting, and an oxide film is formed, which covers the surface of the molten low melting point metal layer 140 to prevent the molten metal from gathering to the three electrode blocks, so that the low melting point metal layer 140 is not easily melted, and the melting time is inaccurate. The invention utilizes an innovative structural design, and can break through the problem to ensure that the fusing time is more accurate.

Since mobile devices are designed to be compact, there is a demand for thinner devices to be mounted therein. In addition to the height required by the housing 170 of the protection device 100 to accommodate the internal components, since the housing 170 is usually manufactured by injection molding, it is not easy to further reduce the height of the housing 170 in terms of process, which is not suitable for the requirement of thinning. In addition, the injection molding requires mold opening, which results in high cost, and the design cost of the protection device 100 is not easy to further reduce.

Disclosure of Invention

The present invention provides a protection device and a circuit protection device including the same, which has the function of over-voltage, over-current and/or over-temperature protection, and can be thinned, and which meets the requirements of miniaturization and thinning of electronic devices.

According to a first aspect of the present invention, there is provided a protective member including a first planar substrate, a second planar substrate, a heating member, a fuse, and an adsorbing member. The first planar substrate includes a first surface, and the second planar substrate includes a second surface facing the first surface. The heating member is disposed on the first surface, and the fuse is disposed above the heating member. The adsorption piece is arranged on the second surface and is positioned above the fuse piece. When overvoltage or overtemperature occurs, the heating element generates heat to melt the fuse element, and the adsorption element adsorbs the molten metal of the fuse element.

In one embodiment, the fuse element is melted to generate an absorption phenomenon in an upward direction and a downward direction.

in one embodiment, the protection element further comprises an insulating frame disposed on the second surface for gathering flux above the fuse.

In one embodiment, the insulating frame comprises an outer frame and an inner frame, the inner frame collects the flux, and the outer frame limits the adhesive or the guide pillar between the first planar substrate and the second planar substrate.

in one embodiment, a gap is formed between the fuse element and the absorbing element, and the gap is spaced apart enough to generate an absorbing effect.

In one embodiment, solder paste is filled in the gap to connect the fuse element and the absorption element.

in one embodiment, the thickness of the protection element is 0.2 to 2 mm.

In one embodiment, the protection element further comprises an insulating layer disposed between the fuse element and the heating element as an isolation.

In one embodiment, the protection device further includes a first electrode and a second electrode disposed on the first surface, and two ends of the fuse are respectively connected to the first electrode and the second electrode.

In one embodiment, the protection element further comprises a third electrode and a fourth electrode disposed on the first surface, and the third electrode and the fourth electrode are respectively connected to two ends of the heating member.

In one embodiment, the heating element is rectangular, and the third electrode and the fourth electrode are connected to two longitudinal ends of the heating element, respectively.

in one embodiment, the protection device further comprises an electrode layer connected to the lower portion of the fuse and electrically connected to the third electrode.

In one embodiment, the protection element forms an equivalent circuit of the fuse element including 2 fuses and the heating element including 1 heater.

According to a second aspect of the present invention, a circuit protection device is provided, which comprises the protection device, and a detector and a switch are collocated with the protection device. The detector is used for detecting the voltage drop or the temperature of a circuit to be protected. The switch is connected with the detector to receive the detection signal of the detector. When the detector detects that the voltage drop or the temperature exceeds a preset value, the switch is switched on, so that current flows through the heating element, the heating element is heated to melt the fuse element, and the adsorption element adsorbs molten metal of the fuse element.

In one embodiment, the fuse element is melted to generate an absorption phenomenon in an upward direction and a downward direction.

in one embodiment, the detector and the switch are disposed on the first surface.

Unlike the prior art, the embodiment of the present invention has not only three electrodes below the fuse, which can adsorb the molten low-melting-point metal, but also an adsorbing member above the fuse, which has the ability to adsorb the molten low-melting-point metal from above or upwards. Therefore, when the heating element is started to heat, the low-melting-point metal contained in the fusing element starts to melt and is absorbed by the upper absorbing element and the lower three electrodes, so that an oxide layer is not easy to form, and the low-melting-point metal is fused to cut off current. Therefore, the invention can overcome the problem of inaccurate fusing time of the low-melting-point metal in the prior art by adsorbing the molten low-melting-point metal from the upper adsorbing piece and the lower electrode together.

The protective element can be manufactured by a large scale by using a printing technology, so that the protective element can be manufactured to be quite thin, and the requirements of miniaturization and thinning of the element are met. In addition, because the technology of injection molding is not used in the process, the die does not need to be opened, and the manufacturing cost can be reduced. In terms of process, the protection device can be manufactured independently on the basis of the upper plane substrate and the lower plane substrate at the initial stage of manufacturing, so that the related processes can be performed simultaneously, and the protection device can be completed by combining the components on the lower plane substrate and the upper plane substrate after the components are completed. Because the manufacturing can be performed simultaneously, the production rate (throughput) can be increased, and the yield can be increased. In addition, the semi-finished products manufactured by the upper plane substrate and the lower plane substrate can be respectively picked out and eliminated if the semi-finished products manufactured by the upper plane substrate and the lower plane substrate have defective products, the semi-finished products do not need to be eliminated after the manufacture of the finished products of the protection elements is finished, and the rejection loss of the defective products can be reduced. Moreover, compared with the conventional protection device structure design, the protection device of the invention has more concentrated fusing time (smaller standard deviation), can bear larger voltage and power, and has more excellent quality stability.

Drawings

Fig. 1 is a schematic structural diagram of a conventional protection element.

fig. 2 is a schematic perspective view of a protection device according to an embodiment of the invention.

Fig. 3A is an exploded schematic view of a protection device according to an embodiment of the invention.

Fig. 3B is an exploded schematic view of a protection device according to another embodiment of the invention.

Fig. 3C is an exploded schematic view of a protection device according to another embodiment of the invention.

FIG. 4 is a cross-sectional view of an embodiment taken along line 1-1 of FIG. 2.

Fig. 5 is a circuit diagram of a circuit protection device according to an embodiment of the invention.

Fig. 6 shows an embodiment of the protective element according to the invention after the fuse has been fused.

Fig. 7 shows a conventional protection element in which a fuse is fused.

Description of reference numerals:

10 protective element

11 first plane base plate

12 second plane substrate

13 fuse

14 heating element

15 insulating layer

16 electrode layer

17 insulating frame

18 silver glue

19 protective layer

20 adsorbing member

21 first electrode

22 second electrode

23 third electrode

24 fourth electrode

25. 26, 27 solder pad

31 solder

32 guide post

33 conductive vias

50 circuit protection device

51 detector

52 switch

61. 71 fuse

62 adsorption element

100 protective element

110 plane substrate

120 heating element

125 heating element electrode

130 insulating layer

140 low melting point metal layer

150 flux

160 electrode layer

165 intermediate electrode

170 outer cover

Detailed Description

In order to make the aforementioned and other technical matters, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

fig. 2 is a perspective view of a protective member 10 according to a first embodiment of the present invention, fig. 3A is an exploded perspective view of the protective member 10, and fig. 4 is a sectional view of the protective member 10 of fig. 2 taken along line 1-1. The protection element 10 includes a first planar substrate 11, a second planar substrate 12, a fuse 13, a heating member 14, an insulating layer 15, an electrode layer 16, an insulating frame 17, a silver paste 18, a protective layer 19, an adsorbing member 20, a first electrode 21, a second electrode 22, a third electrode 23, a fourth electrode 24, a pad 25, a pad 26, and a pad 27. For simplicity and clarity of illustration, the component integrity of fig. 2, 3A and 4 is slightly different, e.g., fig. 4 does not depict insulating layer 19, pads 25, 26 and 27, etc. Preferably, the protection device of the present invention can use the first planar substrate 11 and the second planar substrate 12 as a base to manufacture various components, and then combine them to form the protection device 10. The upper surface (first surface) of the first planar substrate 11 may be printed to form the first electrode 21, the second electrode 22, the third electrode 23 and the fourth electrode 24, which are generally printed at the same time and have the same height (thickness). The third electrode 23 and the fourth electrode 24 are T-shaped and each include an elongated portion extending between the first electrode 21 and the second electrode 22 and an end portion. Next, the heating member 14 is formed, and both ends of the heating member 14 are connected to the third electrode 23 and the fourth electrode 24 to form a conductive path. In one embodiment, the heating element 14 is fabricated by printing and fills the gap between the third electrode 23 and the fourth electrode 24. The insulating layer 15 covers the third electrode 23, the fourth electrode 24 and the heating member 14 to provide insulating isolation. An electrode layer 16 is formed on the surface of the insulating layer 15 at about the center thereof, and then solder paste is printed and the fuse 13 is attached. The fuse 13 connects across the first electrode 21, the electrode layer 16 and the second electrode 22 to form a conductive path. The gap between the fuse 13 and the insulating layer 15 may also be additionally filled with an insulating material, providing a supporting effect to avoid deformation of the fuse 13. The long portion of the third electrode 23 is connected to one end of the heating member 14, and the end portion thereof is electrically connected to the electrode layer 16. The electrode layer 16 is positioned corresponding to the central portion of the fuse 13 as an intermediate electrode of the fuse 13. When the fuse 13 is melted, a phenomenon that the alloy and each other are adsorbed occurs due to a high temperature, and the fuse 13 is adsorbed downward toward the first electrode 21, the electrode layer 16, and the second electrode 22. In one embodiment, the fuse 13 may be connected to the first electrode 21, the electrode layer 16, and the second electrode 22 by using solder 31. The insulating frame 17 is disposed above the fuse 13, or particularly, disposed on the lower surface (second surface) of the second planar substrate 12, and includes an inner frame 171 and an outer frame 172 for gathering flux above the fuse 13. In the present embodiment, the inner frame 171 and the outer frame 172 are rectangular (but not limited to rectangular), and the inner frame 171 is surrounded by the outer frame 172. The adsorbing member 20 may be formed by silver paste printing or electroplating and is disposed on the lower surface of the second planar substrate 12 and surrounded by the inner frame 171. The position of the absorption member 20 corresponds to the upper center of the fuse 13, so that the fuse 13 can be absorbed upwards when melting, and the fusing effect is improved. The first planar substrate 11 and the second planar substrate 12 can be bonded by an adhesive or by the pillars 32 made of silver paste and solder paste to form a support and increase the structural strength. The strip-shaped silver paste 18 is located on two opposite sides of the lower surface of the second planar substrate 12 to assist in fixing and connecting the first planar substrate 11 and the second planar substrate 12. However, the silver paste 18 and the guide posts 32 are not absolutely necessary and may be omitted if the structural strength permits. In particular, the inner frame 171 is used to collect the flux, and the outer frame 172 is used to confine the adhesive or the pillars 32 between the first planar substrate 11 and the second planar substrate 12. The inner frame 171 and the outer frame 172 may be printed to have a very thin thickness, and particularly, the thickness of the inner frame 171 and the outer frame 172 is approximately equal to or slightly greater than the thickness of the suction member 20, and the inner frame 171 may directly contact the upper surface of the fuse 13. The upper surface of the second planar substrate 12 may be covered with a protective layer 19, for example, made of glass or enamel, for protection, and may be used to mark the mark (mark) of the protection device 10. The side of the first planar substrate 11 is provided with a semicircular through hole corresponding to the positions of the first electrode 21, the second electrode 22 and the fourth electrode 24, and the surface of the semicircular through hole can be plated with a conductive layer to form a conductive through hole 33. The conductive vias 33 are located on three different sides of the first planar substrate 11, respectively. The pads 25, 26 and 27 are located on the lower surface of the first planar substrate 11 and serve as an interface for soldering the protection device 10 to a circuit board (not shown). In detail, one conductive via 33 electrically connects the first electrode 21 and the pad 25, another conductive via 33 electrically connects the second electrode 22 and the pad 26, and still another conductive via 33 electrically connects the fourth electrode 24 and the pad 27.

in addition to the foregoing fig. 3A, the third electrode 23 and the fourth electrode 24 connected to the heating member may have different designs as shown in fig. 3B and 3C. Compared with the design in which the portions of the third electrode 23 and the fourth electrode 24 connected to the heating member 14 are longitudinally elongated in fig. 3A, the portions thereof connected to the heating member 14 are transversely designed in fig. 3B and 3C such that the third electrode 23 and the fourth electrode 24 are connected to both longitudinal ends of the heating member 14. Since the heating element 14 is rectangular in this embodiment, the design of fig. 3B and 3C causes the resistance of the heating element 14 to become large (the current flows in the longitudinal direction of the heating element, and the current path becomes long). Generally, as more battery cells (cells) are connected in series in a battery to be protected, a heating element 14 with a larger resistance is required to maintain power stability due to an increase in operating voltage. Thus, the designs of fig. 3B and 3C are suitable for such applications. Alternatively, the heating element 14 may be formed of a lower resistance material to achieve a similar resistance value for a longer current path.

In summary, the main components of the protection device 10 include a first planar substrate 11, a second planar substrate 12, a heating element 14, a fuse element 13, and an absorbing element 20. The upper surface (first surface) of the first planar substrate 11 faces the lower surface (second surface) of the second planar substrate 12. The heating member 14 is disposed on the first surface, and the fuse 13 is disposed above the heating member 14. The absorption member 20 is disposed on the second surface and located above the fuse 13. When an overvoltage or an overtemperature occurs, the heating member 14 generates heat to melt the fuse 13, and the adsorption member 20 adsorbs the molten metal of the fuse 13 from above. In addition, the first electrode 21 and the second electrode 22 located below the fuse 13 also generate a suction effect from below, so that the fuse 13 can simultaneously generate a suction phenomenon in an upward direction and a downward direction when being melted.

In one embodiment, the first planar substrate 11 and the second planar substrate 12 may be insulating planar substrates of square plates, and the material may be selected from, for example, alumina, aluminum nitride, zirconia, or heat-resistant glass plate. The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 may comprise silver, gold, copper, tin, nickel, or other conductive metal, and have a thickness of about 0.005 to 1mm, or more particularly 0.01mm, 0.05mm, 0.1mm, 0.3mm, or 0.5 mm. Instead of using printing to make the electrodes, metal sheets can be used to make them suitable for high voltage applications. The fuse 13 may be made of a low melting point metal or an alloy thereof, such as Sn-Pb-Ag, Sn-Sb, Sn-Zn, Zn-Al, Sn-Ag-Cu, Sn, or the like. The length and width of the fuse 13 can be adjusted according to the amount of current to be passed, but the thickness of the fuse is 0.005mm to 1mm, preferably 0.01mm to 0.5mm, and more preferably 0.02mm to 0.2mm, or particularly 0.05mm, 0.1mm, and 0.3mm, on the basis of not exceeding the length and width of the first planar substrate 11 and the second planar substrate 12. The thick fuse 13 is used for a large current application such as 30 to 100A. The heating element 14 material may include ruthenium oxide (RuO2) and additives such as silver (Ag), palladium (Pd), and platinum (Pt). The insulating layer 15 for isolating the heating element 14 from the fuse 13 may be made of glass (glass), epoxy resin (epoxy), alumina, silicone, or glaze. The adsorbing member 20 can be prepared by silver paste printing or electroplating. The adsorbing member 20 can be represented by one or more strips, blocks, dots, curves, or other shapes, and the composition can be silver, gold, copper, nickel, tin, lead, antimony, or other metals or alloys, and can also be composed of single-layer or multi-layer metals.

As described above, the heating member 14 and the members of the first to fourth electrodes 21, 22, 23 and 24, etc. may be formed on the first planar substrate 11 by thick film printing. Similarly, the insulating frame 17, the suction member 20, and other components may be printed on the surface of the second planar substrate 12. After the components on the surfaces of the first planar substrate 11 and the second planar substrate 12 are respectively manufactured, the second planar substrate 12 is turned over and then combined to form the protection device 10. The main components of the invention can be manufactured by printing and have no outer cover design, so the requirement of thinning can be achieved. In addition, because some components are manufactured on different plane substrates, the manufacturing complexity can be reduced. The second planar substrate 12 may be slightly smaller than the first planar substrate 11, so that the second planar substrate 12 is conveniently mounted in the fixture and then combined with the first planar substrate 11. In addition, due to the manufacturing relationship, if there is a defective product in the semi-finished products of the first and second planar substrates 11 and 12, they can be individually screened out, so that the yield of the final protection device 10 can be increased and the manufacturing cost can be reduced. However, the present invention is not limited to the specific components on the first planar substrate 11 and the second planar substrate 12, and the final structure of the protection device 10 including the features defined in the present invention is still covered by the present invention.

In one embodiment, the surface of the suction member 20 disposed above the fuse 13 may directly contact the fuse 13 or leave a gap, and the gap must be a distance that can generate the suction effect. If there is a gap, the thickness of the gap is not more than 1.5mm, preferably not more than 1mm, and most preferably not more than 0.5mm, and can be filled with solder paste (not shown). The function of the absorption member 20 and the solder paste is to absorb and collect the molten metal of the fuse 13 from above to prevent the metal from flowing around, and the gap can be filled with rosin or other soft metal or flux, but still has the function of absorbing and collecting the molten metal of the fuse 13 from above. The heating member 14 is positioned to correspond to the fuse 13 so that heat generated from the heating member 14 can be efficiently transferred to the fuse 13 to fuse the fuse 13.

In some cases, when the fuse 13 is fused, if the second planar substrate 12 is overheated and is likely to crack, a heat conductive layer (e.g., a silver metal layer, or a material having a thermal conductivity greater than 50W/m · K or 100W/m · K) may be printed on the upper surface of the second planar substrate 12 to enhance heat dissipation and prevent the second planar substrate 12 from cracking. An insulating layer may then be formed over the silver metal layer to prevent the silver metal layer from potentially causing unintended shorting problems.

Since the main components can be manufactured by using printing technology, the thickness of the heating element 14 and the associated first to fourth electrodes 21, 22, 23, 24, etc. can be reduced such that the distance between the first planar substrate 11 and the second planar substrate 12 is only about 0.03-1.5 mm, preferably 0.04-1 mm, and most preferably 0.05-0.5 mm, or especially 0.1mm, 0.3mm, 0.7mm, or 1.2 mm. Therefore, even after the first planar substrate 11 and the second planar substrate 12 are added, the thickness of the protection device 10 is only about 0.2-2 mm, preferably 0.4-1.5 mm, and most preferably 0.5-1 mm, or especially 0.3mm, 0.7mm, and 1.3mm, so as to achieve the effect of thinning. In addition, the dimensional changes of the fuse 13 and the heating member 14 may affect the resistance values thereof, so that the fuse 13 having a low resistance and the heating member 14 having a high resistance are manufactured, i.e., the protective element 10 having a high efficiency is manufactured.

an equivalent circuit diagram of the protection element 10 of the present invention may be shown as a circuit of a dashed box in fig. 5. The first electrode 21 serves as a terminal a1 to which a device to be protected (e.g., a secondary battery or a motor) is connected, and the second electrode 22 is connected to a terminal B1, for example, a charger or other similar device. The third electrode 23 connects the heating element 14 and the electrode layer 16. The other end of the heating member 14 is connected to a fourth electrode 24. The circuit formed by the fuse 13 comprises 2 fuses (fuses) connected in series, and the heating element 14 forms a heater (shown by a resistance symbol), according to the circuit design of the protection element 10. In one embodiment, the fourth electrode 24 is electrically connected to a switch 52, and the switch 52 can be, for example, a Field Effect Transistor (FET). The switch 52, such as the gate (gate) of the FET, is connected to the detector 51, and is connected to the other terminal A2 of the circuit to be protected and the other terminal B2 of the charger. The detector 51 may be an IC device, and has a function of detecting a voltage drop or a temperature. When there is no over-voltage or over-temperature, the switch 52 is open and current passes through the fuse 13, but no current flows through the heating element 14. If an overcurrent occurs, the fuse 13 is blown to provide overcurrent protection. When the detector 51 detects that the voltage exceeds a predetermined value (over-voltage) or the temperature exceeds a predetermined value (over-temperature), the switch 52 is switched to the conducting state, and current flows from the source (source) to the drain (drain) of the switch 52 through the heating element 14. The heating member 14 heats to fuse the fuse member 13, thereby providing overvoltage or overtemperature protection. In summary, B1 to a1, B2 to a2 form 2 power lines provided to the circuit to be protected, and the combination of the protection element 10, the detector 51 and the switch 52 connects the two power lines to form the circuit protection device 50. When the detector 51 detects that the voltage drop or temperature of the circuit to be protected exceeds a preset value, the heating element 14 is activated to melt the fusing element 13. In one embodiment, the first planar substrate 11 can be made larger, for example, the first planar substrate 11 shown in fig. 4 is extended to the left and right, so that the space for mounting the detector 51 and the switch 52 can be provided on the upper surface of the first planar substrate 11 for modularization.

The protection device 10 according to the previous embodiment of the present invention and the conventional protection device 100 shown in fig. 1 of the same specification were tested, in which the resistance of the fuse is 0.0012 Ω, the resistance of the heating member is about 24 Ω, the supply voltage is 42V, and the conditions after the fuse is fused are shown in fig. 6 and 7, respectively. Fig. 6 shows that the fuse element 61 of the protection device of the present invention is divided into upper and lower portions having a distance therebetween after being broken, which is sufficient to completely break the fuse element 61 after it is melted. The position of the suction member 62 is located approximately in the middle of the breaking pitch of the fuse 61 when viewed from above. Referring to fig. 7, although the fuse 71 of the conventional protection element can be broken, the distance of breaking the fuse 71 is significantly smaller, which shows that the breaking effect is not as good as that of the design of the present invention. Therefore, the adsorption piece 62 arranged above the fuse piece 61 can generate adsorption effect when the fuse piece 61 is melted, and the fuse piece 61 can be disconnected timely and in a large area. Further, in the fuse test under the same test conditions and taking 10 samples, the standard deviation of the fuse time of the protection element design of the present invention was 0.783 seconds, and the standard deviation of the fuse time of the conventional protection element design was 1.652 seconds, wherein the standard deviation was calculated according to the following equation (1). Obviously, the fusing time of the protection element of the invention is more concentrated and is better than that of the protection element of the traditional design.

Wherein, x is the fusing time,Is the average number of samples and n is the sample size.

the protection device 10 of the present invention performs a fusing test at different supply voltages of 18.4-60V, wherein the current value, the voltage value and the fusing time are recorded as shown in the following Table 1. When increased to a supply voltage of 56V, the power may reach up to about 132W. When the supply voltage is greater than 60V, the second planar substrate 12 above the test is cracked, and it is supposed that the heat generation amount is concentrated on a certain portion and cannot be uniformly conducted effectively.

Similarly, the conventional protection device 100 performs the fusing test at different supply voltages of 18.4-56V, wherein the current value, the voltage value and the fusing time are recorded as shown in Table 2 below. The samples in table 2 were subjected to a supply voltage of up to 46V, where the power experienced by the device was about 77W. When the supply voltage was 56V, the cover was found to be cracked during the test. Because the outer cover is of a closed structure relative to the planar substrate, the temperature is not easy to escape, so that cracks are easy to be caused by overheating, and the voltage and the power which can be borne by the outer cover are not as good as the design of the protection element.

[ Table 1]

[ Table 2]

The above tables 1 and 2 are only based on the comparison of the fuse test of specific specifications, and do not limit the problem that the protection device of the present invention will always crack the substrate when the supply voltage is 60V. In practical application, the invention can reach the withstand voltage of more than 70V or more in the protection elements with different specifications, or is suitable for higher power application.

The equivalent circuit of the protection device of the previous embodiment includes 2 fuses and 1 heater. However, other different circuit designs can be used to form a circuit including, for example, 2 fuses and 2 heaters, or 1 fuse and 1 heater, and still be covered by the inventive technique of the present invention. In yet another embodiment, the fuse element is electrically connected to 2 pads to form one conductive path, and the heating element is connected to another 2 pads to form another conductive path, whereby current flowing through the heating element can be independently controlled to fuse the fuse element.

The invention can break through the problems of difficult fusing and inaccurate fusing time of the traditional protection element and improve the fusing effect. The protective element of the invention not only has the capability of downward adsorption, but also can cause the phenomenon of alloy adsorption to each other due to high temperature by increasing the arrangement of the upper adsorption piece, so that the molten low-melting-point metal in the fuse piece can be adsorbed to the upper adsorption piece, thereby preventing the oxide layer from being generated at high temperature, and further leading the fuse piece to be smoothly fused.

the protective element of the invention can fully utilize the characteristics of the printing technology, so that the protective element can be made to be quite thin, and the requirements of element miniaturization and thinning are met. The injection molding technology is not used in the process, so that the process is simplified, and the manufacturing cost of the mold can be saved. In addition, compared with the traditional protection element structure design, the protection element has the advantages that the fusing time is concentrated (the standard deviation is small), and the protection element can bear higher voltage and power, so that the quality stability is more excellent.

While the technical content and the technical features of the invention have been disclosed, those skilled in the art may make various substitutions and modifications based on the teaching and the disclosure of the invention without departing from the spirit of the invention. Therefore, the scope of the present invention should not be limited to the technical contents disclosed in the embodiments, but includes various alternatives and modifications without departing from the present invention, and is covered by the following scope of protection.

Claims (15)

1. A protective element, comprising:

A first planar substrate including a first surface;

A second planar substrate including a second surface facing the first surface;

A heating element disposed on the first surface;

A fuse element disposed above the heating element;

The suction piece is arranged on the second surface and is positioned above the fuse piece;

Wherein when an overvoltage or an overtemperature occurs, the heating member generates heat to melt the fuse element, and the adsorption member adsorbs the molten metal of the fuse element;

wherein the thickness of the protection element is 0.2-2 mm.

2. The protective member according to claim 1, wherein the fuse element is melted to generate an attraction phenomenon in upward and downward directions.

3. The protective member of claim 1 further comprising an insulating frame disposed on the second surface for concentrating flux over the fuse.

4. The protective device of claim 3, wherein the insulating frame comprises an outer frame and an inner frame, the inner frame collects the flux, and the outer frame confines the adhesive or the guiding posts between the first and second planar substrates.

5. The protective member according to claim 1, wherein a gap is formed between the fuse element and the absorbing element, and the gap is spaced apart from the fuse element by a distance sufficient to generate an absorbing effect.

6. The protection device of claim 5, wherein the gap is filled with solder paste to connect the fuse element and the absorption element.

7. The protective member according to claim 1, further comprising an insulating layer disposed between the fuse element and the heating element as a barrier.

8. The protective element of claim 1, further comprising a first electrode and a second electrode disposed on the first surface, wherein the fuse is connected to the first electrode and the second electrode at two ends thereof.

9. the protective member according to claim 8, further comprising a third electrode and a fourth electrode disposed on the first surface, the third electrode and the fourth electrode being connected to both ends of the heating member, respectively.

10. The protective member according to claim 9, wherein the heating member has a rectangular shape, and the third electrode and the fourth electrode are connected to both longitudinal ends of the heating member, respectively.

11. The device of claim 9, further comprising an electrode layer connected to the fuse link under the middle portion and electrically connected to the third electrode.

12. The protective member according to claim 11, wherein the protective member forms an equivalent circuit in which the fuse includes 2 fuses and the heating member includes 1 heater.

13. A circuit protection device, comprising:

A protection device, comprising:

A first planar substrate including a first surface;

A second planar substrate including a second surface facing the first surface;

A heating element disposed on the first surface;

A fuse element disposed above the heating element; and

The suction piece is arranged on the second surface and is positioned above the fuse piece;

wherein the thickness of the protective element is 0.2-2 mm;

A detector for detecting the voltage drop or temperature of a circuit to be protected; and

A switch connected to the detector for receiving the detection signal;

When the detector detects that the voltage drop or the temperature exceeds a preset value, the switch is switched on, so that current flows through the heating element, the heating element is heated to melt the fuse element, and the adsorption element adsorbs molten metal of the fuse element.

14. The circuit protection device of claim 13, wherein the fuse element is melted to generate an attraction phenomenon in upward and downward directions.

15. The circuit protection device of claim 13, wherein the detector and the switch are disposed on the first surface.