Protective element

Abstract

A protection element comprises a substrate, a heater and a fuse element. The heater comprises a first heating piece and a second heating piece which are respectively arranged on the upper surface and the lower surface of the substrate. The sum of the surface areas of the heaters is 18% to 72% based on 100% of the surface area of the substrate. The fusing piece is arranged above the first heating piece. Thus, when an overvoltage occurs, the heater is heated and the fuse link is fused.

Description

TECHNICAL FIELD

[0001] The present invention relates to a protection element, and more particularly, to a protection element with double heating elements. BACKGROUND

[0002] A protection element for cutting off overcurrent is widely known as a fuse made of low-melting-point metals such as lead, tin, and antimony. Subsequently, in terms of preventing overcurrent and overvoltage, a protection element has been continuously developed, which includes a low-melting-point metal layer and a heating layer sequentially laminated on a planar substrate. When an overvoltage occurs, the heating layer generates heat, and the heat is transferred upward from the bottom to heat an electrode carrying the low-melting-point metal, thereby melting the low-melting-point metal and cutting off the current flowing therethrough, so as to protect the relevant circuit or electronic device.

[0003] In recent years, mobile devices have been highly popularized, and information products such as mobile phones, computers, and personal mobile assistants can be seen everywhere, so that people's dependence on information products has been increasing day by day. However, news about the explosion of batteries of portable electronic products such as mobile phones during charging and discharging has occurred from time to time. Therefore, manufacturers have gradually improved the design of the aforementioned overcurrent and overvoltage protection elements to enhance the protection measures of the battery during charging and discharging, so as to prevent the battery from exploding due to overvoltage or overcurrent during charging and discharging.

[0004] The protection element is connected in series with the circuit of the battery, and the low-melting-point metal layer and the heating layer of the protection element are electrically connected to a switch and an integrated circuit (IC) element. In this way, when the IC element measures an overvoltage, the switch is turned on to make the current pass through the heating layer of the protection element, so that the heating layer generates heat to melt the fuse, thereby making the circuit of the battery in an open state to achieve overvoltage protection. Those skilled in the art can also fully understand that when overcurrent occurs, a large amount of current flowing through the fuse will heat the fuse to melt it, thereby achieving overcurrent protection.

[0005] Please refer to Figure 1Figure 1 is a cross-sectional view of a known protection element 10. The protection element 105 mainly comprises a substrate 11, a heater consisting of a first heating element 13a and a second heating element 13b, and a fuse consisting of a core metal layer 15b and a top cover layer 15c. A connecting layer 15a is coated on the surface of a first electrode 12a, a second electrode 12b and a substrate auxiliary electrode 12e. Through the connecting layer 15a, both ends of the core metal layer 15b are connected to the first electrode 12a and the second electrode 12b respectively, while the center is connected to the substrate auxiliary electrode 12e. The first electrode 12a and the second electrode 12b are electrically connected to a power input terminal and a power output terminal. In this way, the fuse is connected in series with an electronic product (such as a battery) to be protected. When the current flowing through is too large or the temperature is too high, the fuse will be melted due to overheating. The first heating element 13a is arranged below the fuse and is covered by a substrate insulating layer 14a. The second heating element 13b is arranged above a cover 16 of the fuse and is covered by a cover insulating layer 14b. A cover auxiliary electrode 12f is connected to the top cover layer 15c. The fuse and the heater are electrically connected to a switch and a detection element (not shown). When the detection element measures an overvoltage, the switch is switched to make the heater in an electrically conductive state. The current flows through the heater, so that the heater generates heat to melt the fuse.

[0006] To shorten the melting time, the surface area of the heater is traditionally increased, thereby increasing the heating rate. However, this will face at least two problems.

[0007] Firstly, in a single plane, the surface area of the heater is limited by the arrangement of surrounding elements. For example, regardless of the presence of the substrate insulating layer 14a, the first heating element 13a must maintain a certain distance D from the electrode 12b, otherwise a short circuit will occur. In addition to the aforementioned electrode 12b, if other functional elements are added to the upper surface of the substrate 11, the size of the surface area of the first heating element 13a will also be limited.

[0008] Secondly, even if the heaters are added to different planes to increase their surface area, there are still problems of high process complexity and component damage. For example, to avoid the situation of the heater itself being burned out, the first heating element 13a and the second heating element 13b are respectively arranged on two carriers, i.e. the substrate 11 and the cover 16. However, this causes a process burden of the heater. In more detail, the first heating element 13a and its associated components (electrodes and insulating layers, etc.) must be independently manufactured on the substrate 11, and the second heating element 13b and its associated components (electrodes and insulating layers, etc.) must be independently manufactured on the cover 16. That is, the heater must be independently manufactured on two production lines, so that the process steps become more complex. The foregoing situation is particularly evident in mass production. In addition, the thermal energy of the first heating element 13a and the second heating element 13b is vertically accumulated on the cover 16. If the heating source (i.e. the second heating element 13b) is directly located on the cover, it is easy to cause the cover 16 to crack. Alternatively, the structure of the cover 16 is relatively fragile, and if the voltage or power of the second heating element 13b is not properly controlled, it is also easy to cause the cover 16 to crack or even burst.

[0009] Therefore, the known protective component still has considerable room for improvement. SUMMARY

[0010] The present application aims to provide a protective component to solve at least one of the above problems.

[0011] The present application provides a protective component that melts quickly. In the protective component, the heater has a plurality of heating elements located on the same substrate. The total surface area of the heating elements is controlled within a certain range, so as to shorten the melting time while maintaining the structural integrity of the surrounding components (i.e. components other than the melting component). In addition, the heater can withstand higher power and voltage, and will not burn out at the moment of action to cause incomplete melting of the melting component. More importantly, the heating elements can be manufactured on the same substrate, which improves the performance of the components while reducing the process complexity.

[0012] According to an embodiment of the present application, a protective component includes a substrate, a heater, and a melting component. The substrate has an upper surface and a lower surface opposite to the upper surface. The heater includes a first heating element arranged on the upper surface and a second heating element arranged on the lower surface. The substrate has a first surface area. The first heating element has a second surface area, and the second heating element has a third surface area. The sum of the second surface area and the third surface area is 18% to 72% based on 100% of the first surface area. The melting component is arranged above the first heating element, so that when an overvoltage occurs, the heater heats up and causes the melting component to melt.

[0013] According to some embodiments, the sum of the second and third surface areas is 42% to 70%. At 14W of power, the fuse breaks within 15 seconds. At 43W of power, the fuse breaks within 5 seconds.

[0014] According to some embodiments, the ratio obtained by dividing the resistance value of the first heating element by the resistance value of the second heating element is equal to or less than 2.

[0015] According to some embodiments, the ratio obtained by dividing the resistance value of the first heating element by the resistance value of the second heating element is between 1 and 1.6.

[0016] According to some embodiments, the second surface area of ​​the first heating element is the same as the third surface area of ​​the second heating element.

[0017] According to some embodiments, the second surface area of ​​the first heating element is smaller than the third surface area of ​​the second heating element.

[0018] According to some embodiments, the protective element further includes an electrode assembly. The electrode assembly has a first electrode, a second electrode, a third electrode, and a fourth electrode. The first electrode and the second electrode are disposed opposite each other on the substrate, while the third electrode and the fourth electrode are disposed opposite each other on the substrate. The two ends of a fusible element are respectively connected to the first electrode and the second electrode. The two ends of a first heating element are respectively connected to the third electrode and the fourth electrode on the upper surface of the substrate. The two ends of a second heating element are respectively connected to the third electrode and the fourth electrode on the lower surface of the substrate, thereby connecting the first heating element and the second heating element in parallel.

[0019] According to some embodiments, the electrode assembly extends inward from the edge of the upper surface or the edge of the lower surface of the substrate by a distance of 0.1 mm or more.

[0020] According to some embodiments, the electrode assembly further includes an auxiliary electrode. The auxiliary electrode extends from the third electrode toward the fourth electrode between the fuse and the first heating element, and is connected to the fuse.

[0021] According to some embodiments, the electrode assembly further includes vias. The substrate has sidewalls connecting an upper surface and a lower surface of the substrate. The third electrode does not extend to the sidewalls of the substrate and has a first portion and a second portion located on the upper surface and lower surface of the substrate, respectively. The vias penetrate the upper and lower surfaces of the substrate, such that the first portion and the second portion of the third electrode are electrically connected.

[0022] According to some embodiments, the protective element further includes a first insulating layer and a second insulating layer. The first insulating layer is disposed between the auxiliary electrode and the first heating element, and extends toward the first electrode and the second electrode to the upper surface of the substrate, and the first insulating layer does not contact the first electrode, the second electrode, or the fuse. The second insulating layer covers the second heating element, and extends toward the first electrode and the second electrode to the lower surface of the substrate, and the second insulating layer does not contact the first electrode and the second electrode.

[0023] According to some embodiments, the heater further includes a third heating element. The ratio of the resistance values ​​of the first heating element, the second heating element, and the third heating element is defined as x:y:z. x, y, and z are each between 1 and 1.1.

[0024] According to some embodiments, the protective element further includes a cover. The cover has a receiving space. The cover is connected to the substrate such that the fuse is located within the receiving space and isolated from the external environment. The cover does not include a heater.

[0025] According to some embodiments, the cover is made of a material selected from the group consisting of polybenzimidazole, polyetheretherketone, polyphenylene sulfide, liquid crystal polymer, polyphthalamide, and combinations thereof. The substrate is made of a material selected from the group consisting of alumina, aluminum nitride, zirconium oxide, glass ceramics, and combinations thereof.

[0026] According to some embodiments, the protective element further includes another substrate. This other substrate has an upper surface and a lower surface opposite to the upper surface, and the upper surface of this other substrate directly contacts the lower surface of the substrate and the second heating element, such that the second heating element is completely covered between the substrate and the other substrate.

[0027] According to one embodiment of the present invention, a protective element includes a substrate, a heater, and a fuse. The substrate has an upper surface and a lower surface opposite to the upper surface. The heater includes a first heating element, a second heating element, and a third heating element. The first heating element is disposed on the upper surface, and the second heating element is disposed on the lower surface. The third heating element is disposed above the first heating element, and the third heating element is separated from the first heating element by an insulating layer. The substrate has a first surface area. The first heating element has a second surface area, the second heating element has a third surface area, and the third heating element has a fourth surface area. The sum of the second, third, and fourth surface areas is 50% to 70%, with the first surface area being 100%. The fuse is disposed above the third heating element, whereby, in the event of an overvoltage, the heater heats up and causes the fuse to melt.

[0028] According to some embodiments, the sum of the second, third, and fourth surface areas is 60%.

[0029] According to some embodiments, the ratio of the resistance values ​​of the first heating element, the second heating element, and the third heating element is defined as x:y:z, where x, y, and z are each between 1 and 1.1.

[0030] According to some embodiments, the protective element further includes a cover. The cover has a receiving space. The cover is connected to the substrate such that the fuse is located within the receiving space and isolated from the external environment. The cover does not include a heater.

[0031] According to one embodiment of the present invention, a protective element includes a substrate assembly, a heater, and a fuse. The substrate assembly has a first substrate and a second substrate, wherein the first substrate has an upper surface and a lower surface opposite to the upper surface, and the second substrate is stacked on the lower surface. The heater includes a first heating element, a second heating element, and a third heating element. The first heating element is disposed on the upper surface, and the second heating element is disposed on the lower surface, thereby directly contacting the second substrate and being sandwiched between the first and second substrates. The third heating element is disposed below the second substrate. The substrate has a first surface area. The first heating element has a second surface area, the second heating element has a third surface area, and the third heating element has a fourth surface area. Taking the first surface area as 100%, the sum of the second, third, and fourth surface areas is 50% to 70%. The fuse is disposed above the first heating element, thereby causing the heater to heat up and the fuse to melt when an overvoltage occurs.

[0032] According to some embodiments, the sum of the second, third, and fourth surface areas is 60%.

[0033] According to some embodiments, the ratio of the resistance values ​​of the first heating element, the second heating element, and the third heating element is defined as x:y:z, where x, y, and z are each between 1 and 1.1.

[0034] According to some embodiments, the protective element further includes a cover. The cover has a receiving space. The cover is connected to the substrate such that the fuse is located within the receiving space and isolated from the external environment. The cover does not include a heater. Attached Figure Description

[0035] Figure 1 Showing a cross-sectional view of a known protective element;

[0036] Figure 2a Showing a top view of the protective element of the present invention;

[0037] Figure 2b show Figure 2a A bottom view of the protective element;

[0038] Figure 2c show Figure 2a A cross-sectional view of the protective element along line segment AA;

[0039] Figure 2d show Figure 2a The equivalent circuit diagram of the protection element;

[0040] Figure 2e show Figure 2a An equivalent circuit diagram of another embodiment of the protective element;

[0041] Figures 3 to 5 Various embodiments of the protective element of the present invention are shown; and

[0042] Figure 6 and Figure 7 This shows the heating conditions of the fuse of the present invention at 14W and 43W.

[0043] The attached figures are labeled as follows:

[0044] 10 protective components

[0045] 11 substrate

[0046] 12a First Electrode

[0047] 12b second electrode

[0048] 12e substrate auxiliary electrode

[0049] 12f top cover auxiliary electrode

[0050] 13a First heating element

[0051] 13b Second heating element

[0052] 14a substrate insulating layer

[0053] 14b Top Cover Insulation Layer

[0054] 15a Connector Layer

[0055] 15b core metal layer

[0056] 15c top cover

[0057] 16 caps

[0058] 20 protective components

[0059] 21 substrate

[0060] 21a First Substrate

[0061] 21b Second Substrate

[0062] 22a First Electrode

[0063] 22b second electrode

[0064] 22c third electrode

[0065] 22d fourth electrode

[0066] 22e auxiliary electrode

[0067] 23a First heating element

[0068] 23b Second heating element

[0069] 23c third heating element

[0070] 24 insulation layers

[0071] 24a First Insulation Layer

[0072] 24b Second Insulation Layer

[0073] 24c third insulation layer

[0074] 25 fuses

[0075] 25a Connector Layer

[0076] 25b core metal layer

[0077] 25c top cover

[0078] 26 caps

[0079] 30 protective components

[0080] 40 protective components

[0081] 50 protective components

[0082] D distance

[0083] E electrode edge distance

[0084] H-guide hole

[0085] L1 First Length

[0086] L2 second length

[0087] L3 third length

[0088] S-side wall

[0089] S1 upper surface

[0090] S2 lower surface

[0091] ST sidewall groove

[0092] W1 First Width

[0093] W2 Second Width

[0094] W3 Third Width Detailed Implementation

[0095] To make the above and other technical contents, features and advantages of the present invention more apparent and understandable, relevant embodiments are described below in conjunction with the accompanying drawings for detailed explanation.

[0096] Please refer to Figure 2a and Figure 2b The front and back sides of the protective element 20 of the present invention are shown respectively. The protective element 20 includes a substrate 21, an electrode assembly, a heater, and a fuse 25. The fuse 25 may be composed of a single layer or multiple layers of metal layers and a cover layer, and can be quickly melted in the event of overvoltage, overcurrent, and / or overtemperature, thereby protecting the electronic product. The electrode assembly includes a first electrode 22a, a second electrode 22b, a third electrode 22c, a fourth electrode 22d, and an auxiliary electrode 22e. The first electrode 22a, the second electrode 22b, the third electrode 22c, and the fourth electrode 22d are printed on the substrate 21, while the auxiliary electrode 22e is pulled out perpendicular to the third electrode 22c along the z-axis, and then extends parallel to the substrate 21 along the x-axis to the right in the top view. The first electrode 22a is electrically connected to the power input terminal, and the second electrode 22b is electrically connected to the power output terminal. The fuse 25 is not attached to the substrate 21, bridging the first electrode 22a and the second electrode 22b, thus connecting in series with the electronic product (such as a battery) to be protected. When the current flowing through it is too large or the temperature is too high, the fuse 25 will melt due to overheating, preventing the battery from exploding during charging and discharging. Furthermore, to further improve the melting efficiency of the fuse 25, the present invention further provides heaters on the front and back sides of the substrate 21. More specifically, the heater includes a first heating element 23a and a second heating element 23b. The first heating element 23a is disposed on the front side of the substrate 21 (see reference 23b). Figure 2a The second heating element 23b is disposed on the back side of the substrate 21 (see reference). Figure 2bThe first heating element 23a is printed on the front side of the substrate 21 and connects to the third electrode 22c and the fourth electrode 22d, thus located below the fuse 25 and the auxiliary electrode 22e. The second heating element 23b is printed on the back side of the substrate 21 and similarly connects to the third electrode 22c and the fourth electrode 22d. The fuse 25 and the heater are electrically connected to a switch and a detection element (not shown). When the detection element detects an overvoltage, the switch is switched to make the heater electrically conductive. Current flows through the heater, causing the heater to generate heat and melt the fuse 25. The heater may be made of ruthenium oxide, nickel-chromium alloy, lead-germanium alloy, silicon-germanium alloy, or a combination thereof. In addition, the auxiliary electrode 22e is connected to the fuse 25. More specifically, the auxiliary electrode 22e extends along the x-axis from the third electrode 22c toward the fourth electrode 22d between the fuse 25 and the first heating element 23a, and is connected to the fuse 25. The auxiliary electrode 22e helps to transfer the heat generated by the heater and adsorb the molten fuse 25. The protective element 20 further includes a first insulating layer 24a and a second insulating layer 24b covering the first heating element 23a and the second heating element 23b, respectively. The first insulating layer 24a covers the first heating element 23a and extends beyond the first heating element 23a in the directions (i.e., the y-axis) toward the first electrode 22a and the second electrode 22b, respectively, and is finally attached to the substrate 21. Similarly, the second insulating layer 24b covers the second heating element 23b and extends beyond the second heating element 23b in the directions (i.e., the y-axis) toward the first electrode 22a and the second electrode 22b, respectively, and is finally attached to the substrate 21. It should also be noted that, in Figure 2a and Figure 2b In the diagram, solid lines are used to show exposed areas when viewed from above or below, while dashed lines are used to show covered areas when viewed from above or below. Therefore, it can be seen that in... Figure 2a In the middle, the auxiliary electrode 22e, the first heating element 23a, the first insulating layer 24a, the auxiliary electrode 22e, and the fuse element 25 are sequentially stacked on the substrate 21; while Figure 2b In the middle, the second heating element 23b and the second insulating layer 24b are stacked sequentially on the substrate 21.

[0097] It should be noted that in this invention, the first heating element 23a and the second heating element 23b are jointly fabricated on the same substrate 21, and their surface areas are set within a specific range, as detailed below. The top and bottom views of the substrate 21 (i.e., the surface area of ​​the substrate 21) Figure 2a The surface area of ​​substrate 21 and Figure 2b The surface area of ​​substrate 21 is the same. Figure 2a In the top view, the top-view area of ​​the substrate 21 is defined as the first surface area, while the top-view area of ​​the first heating element 23a is defined as the second surface area. Figure 2bIn the bottom view, the bottom-view area of ​​the second heating element 23b is defined as the third surface area. The substrate 21 has a first length L1 and a first width W1, and the area obtained by multiplying the first length L1 by the first width W1 is the aforementioned first surface area. The first heating element 23a has a second length L2 and a second width W2, and the area obtained by multiplying the second length L2 by the second width W2 is the aforementioned second surface area. The second heating element 23b has a third length L3 and a third width W3, and the area obtained by multiplying the third length L3 by the third width W3 is the aforementioned third surface area. The first length L1, second length L2, and third length L3 are substantially parallel to the x-axis, while the first width W1, second width W2, and third width W3 are substantially parallel to the y-axis. By arranging at least two heating elements, such as the first heating element 23a and the second heating element 23b, the heating area of ​​the heater is expanded.

[0098] In this invention, taking the first surface area as 100%, the sum of the second and third surface areas can be between 18% and 72%, for example, 18%, 24%, 30%, 36%, 42%, 48%, 54%, 60%, 66%, or 72%. The second surface area of ​​the first heating element 23a and the third surface area of ​​the second heating element 23b can be the same or different, as long as the percentage of their sum falls within the aforementioned range. If the sum of the second and third surface areas is less than 18%, the heat energy generated by the heater is insufficient to melt the fuse 25. Furthermore, when the second surface area (or third surface area) is less than 9%, the small area is difficult to precisely control during printing. If the sum of the second and third surface areas is greater than 72%, overheating will occur. Overheating may cause the fuse 25 to fail to melt or structural defects. For example, the heater may burn out due to the high energy generated at the moment of energization before it even begins to transfer heat energy to the fuse 25. Alternatively, the heat generated by the heater may be too high, causing the substrate 21 or cover 26 to crack or burst, further damaging other components besides the protective element 20 (i.e., the parts of the electronic product to be protected). In a preferred embodiment, with the first surface area being 100%, the sum of the second and third surface areas is 42% to 70%.

[0099] Furthermore, the area of ​​the heater should not be too large to avoid affecting the arrangement of the surrounding electrodes. For example, the first electrode 22a extends inward from the edge of the substrate 21 by a certain distance, which can also be called the electrode distance E. The length of the electrode distance E must be at least 0.1 mm. The electrode is mainly made of silver paste, which has better conductivity than the fuse 25. If the length of the electrode distance E is less than 0.1 mm, there will be a problem of low conductivity. In addition, if the electrode distance E is too narrow, it is not only difficult to control it with such precision when printing the electrode, but it is also difficult for the fuse 25 to be properly soldered to the electrode. It can also be noted that the substrate 21 has a sidewall groove ST provided at the location of the first electrode 22a. The first electrode 22a on the front side of the substrate 21 (i.e. Figure 2a The first electrode 22a) can be connected to the first electrode 22a on the back side of the substrate 21 via the sidewall trench ST. Figure 2b The first electrode 22a) is electrically connected. When the protective element 20 is soldered to an external component, the design of the sidewall trench ST facilitates the reception of solder. The electrode group may also include a via H. In this invention, the substrate 21 has a sidewall S connecting the upper surface S1 and the lower surface S2 of the substrate 21. The third electrode 22c does not extend to the sidewall S of the substrate 21 and has a first portion and a second portion located on the upper surface S1 and the lower surface S2 of the substrate 21, respectively. That is, the first portion of the third electrode 22c is located on the front side of the substrate 21, while the second portion of the third electrode 22c is located on the back side of the substrate 21. The via H penetrates the upper surface S1 and the lower surface S2 of the substrate 21, so that the first portion and the second portion of the third electrode 22c are electrically connected. It should be noted that this invention increases the heater area on the same substrate 21 without affecting the freedom of choice in structural design. For example, in some cases, the via H must be provided according to design requirements, forcing the edge of the third electrode 22c to be moved more inward. In this way, the area of ​​the heater will be relatively reduced. In heaters with only a single-sided heating element, such designs result in insufficient heater area and poor heating performance. However, the heater of the present invention has at least two heating elements (i.e., a first heating element 23a and a second heating element 23b). As long as the sum of the second surface area of ​​the first heating element 23a and the third surface area of ​​the second heating element 23b is set to 18% or more, the fuse element 25 can be effectively melted. Therefore, the aforementioned design of the guide hole H does not affect the performance of the heater of the present invention. It should be understood that the design of the sidewall groove ST can also be applied to the second electrode 22b, the third electrode 22c, and the fourth electrode 22d, and the design of the guide hole H can also be applied to the first electrode 22a, the second electrode 22b, and the fourth electrode 22d.

[0100] Please continue to refer to Figure 2c ,show Figure 2a A cross-sectional view of the protective element 20 along line segment AA.

[0101] The fuse 25 includes a core metal layer 25b and a top cover layer 25c above the core metal layer 25b. The two ends of the fuse 25 are connected to the first electrode 22a and the second electrode 22b respectively via a connecting layer 25a, while its center is connected to an auxiliary electrode 22e. The connecting layer 25a can be solder. The substrate 21 has an upper surface S1 and a lower surface S2 opposite to the upper surface S1 (i.e., the front and back sides of the aforementioned substrate 21, respectively), and the area of ​​the upper surface S1 is the aforementioned first surface area. The heater includes a first heating element 23a disposed on the upper surface S1 and a second heating element 23b disposed on the lower surface S2. In other words, in this invention, taking the area of ​​the upper surface S1 as 100%, the sum of the second surface area of ​​the first heating element 23a and the third surface area of ​​the second heating element 23b is 18% to 72%. In one embodiment, to increase process convenience, the second surface area of ​​the first heating element 23a and the third surface area of ​​the second heating element 23b are the same. If the second surface area of ​​the first heating element 23a is the same as the third surface area of ​​the second heating element 23b, the size of the screen plate does not need to be changed during the formation of the first heating element 23a and the second heating element 23b, significantly improving process convenience in mass production. In one embodiment, the upper surface S1 carries more additional components according to design requirements, which relatively limits the size of the second surface area of ​​the first heating element 23a. Therefore, the second surface area of ​​the first heating element 23a can be smaller than the third surface area of ​​the second heating element 23b. In the aforementioned embodiment, the sum of the second surface area of ​​the first heating element 23a and the third surface area of ​​the second heating element 23b still falls within the range of 18% to 72%, so design changes to the upper surface S1 will not affect the melting performance.

[0102] It should be understood that the resistance values ​​of the first heating element 23a and the second heating element 23b can also be designed to be different, thereby expanding the voltage application range or handling high power applications. According to some embodiments, the ratio obtained by dividing the resistance value of the first heating element 23a by the resistance value of the second heating element 23b is equal to or less than 2, for example, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2. Preferably, the ratio obtained by dividing the resistance value of the first heating element 23a by the resistance value of the second heating element 23b is between 1 and 1.6. If the aforementioned ratio is between 1 and 1.6, the heater can withstand 400 watts (W) of power without burning out.

[0103] In some cases, the area of ​​the upper surface S1 of the substrate may differ from the area of ​​the lower surface S2. For example, the width of the lower surface S2 along the y-axis may be designed to be longer than the first width W1 of the upper surface S1 along the y-axis, forming a trapezoidal cross-section that is wider at the bottom and narrower at the top (not shown). This design causes the sidewall trench ST to extend obliquely inward from the lower surface S2, which is beneficial for solder climbing. Furthermore, the distance by which the electrode assembly extends inward from the edge of the upper surface S1 or the edge of the lower surface S2 of the substrate 21 is the aforementioned electrode edge distance E. Figure 2c In this context, the electrode edge distance E is the distance that the first electrode 22a extends inward from the center of the sidewall groove ST on the upper surface S1 or the lower surface S2.

[0104] As mentioned above, the heater is covered by a first insulating layer 24a and a second insulating layer 24b. The first insulating layer 24a is disposed between the auxiliary electrode 22e and the first heating element 23a, and extends along the y-axis toward the first electrode 22a and the second electrode 22b, and then extends to the upper surface S1 of the substrate 21. The first insulating layer 24a does not contact the first electrode 22a, the second electrode 22b, or the fuse 25. The second insulating layer 24b covers the second heating element 23b and extends along the y-axis toward the first electrode 22a and the second electrode 22b, and then extends to the lower surface S2 of the substrate 21. Similarly, the second insulating layer 24b does not contact the first electrode 22a and the second electrode 22b. Since neither the first insulating layer 24a nor the second insulating layer 24b contacts the first electrode 22a and the second electrode 22b, the heat energy of the heater can be effectively concentrated and transferred upward to the fuse 25.

[0105] The protective element 20 may further include a cover 26 with a receiving space. Figure 2aFor ease of explanation, the cover 26 is not shown. The cover 26 is connected to the substrate 21, so that the fused element 25 is located in the accommodating space and isolated from the external environment. It should be understood that the cover 26 in this invention does not contain any heating element, that is, it does not contain a heater or other element used to heat the fused element 25 and accelerate its melting. In this way, the design considerations for the cover 26 are simpler, and it can be quickly manufactured by injection molding without the need to print heating elements and related components on it, making the manufacturing process simple. The composition of the cover 26 may be different from that of the substrate 21. The composition of the cover 26 may be selected from the group consisting of polybenzimidazole (PBI), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyphthalamide (PPA), and combinations thereof. The substrate 21 may be composed of materials such as alumina, aluminum nitride, zirconium oxide, glass ceramics and combinations thereof.

[0106] Please continue to refer to Figure 2d This is the equivalent circuit diagram for protection element 20. Figure 2d In this configuration, the first heating element 23a and the second heating element 23b are connected in parallel. That is, the two ends of the first heating element 23a are respectively connected to the third electrode 22c and the fourth electrode 22d along the x-axis on the upper surface S1 of the substrate 21 (and refer to the reference). Figure 2a The two ends of the second heating element 23b are respectively connected to the third electrode 22c and the fourth electrode 22d along the x-axis on the lower surface S2 of the substrate 21 (and refer to the same). Figure 2b Thus, the first heating element 23a and the second heating element 23b are connected in parallel. Of course, depending on design requirements, the first heating element 23a and the second heating element 23b can also be modified to be connected in series, and have the following characteristics: Figure 2e The equivalent circuit diagram is shown. This invention can have various different embodiments; please refer to [the documentation / reference]. Figures 3 to 5 .

[0107] Figure 3 A cross-sectional view of the protective element 30 is shown for one embodiment of the present invention. Figure 3 and Figure 2cThe main difference lies in the number of substrates and the position of the second heating element 23b. Simply put, the protective element 30 comprises a substrate group consisting of multiple substrates (such as the first substrate 21a and the second substrate 21b), with the second heating element 23b sandwiched between the two substrates. More specifically, the first substrate 21a has an upper surface S1 and a lower surface S2; similarly, the second substrate 21b has an upper surface and a lower surface opposite to the upper surface. The upper surface of the second substrate 21b directly contacts the lower surface S2 of the first substrate 21a and the second heating element 23b, so that the second heating element 23b completely covers the space between the first substrate 21a and the second substrate 21b. An insulating layer 24 is disposed between the auxiliary electrode 22e and the first heating element 23a, extending along the y-axis towards the first electrode 22a and the second electrode 22b, and then extending to the upper surface S1 of the first substrate 21a. In other words, the aforementioned second heating element 23b is an embedded design, thus eliminating the need for a separate printed insulating layer to cover the second heating element 23b. It should be noted that the same components as those described above use the same component symbols and can have the same functions as described above. To avoid redundancy, they will not be repeated here.

[0108] Figure 4 A cross-sectional view of the protective element 40 is shown for one embodiment of the present invention. Figure 4 and Figure 2cThe main difference lies in the number of heating elements. The heater includes a first heating element 23a, a second heating element 23b, and a third heating element 23c. Correspondingly, in addition to the first insulating layer 24a and the second insulating layer 24b, the protective element 40 also includes a third insulating layer 24c. As mentioned above, the first heating element 23a and the second heating element 23b are printed on the upper surface S1 and lower surface S2 of the substrate 21, respectively, and are covered by the first insulating layer 24a and the second insulating layer 24b, respectively. The first insulating layer 24a is disposed between the auxiliary electrode 22e and the first heating element 23a, and extends along the y-axis toward the first electrode 22a and the second electrode 22b, and then extends to the upper surface S1 of the substrate 21. The second insulating layer 24b covers the second heating element 23b, and extends along the y-axis toward the first electrode 22a and the second electrode 22b, and then extends to the lower surface S2 of the substrate 21. The third heating element 23c is disposed above the first heating element 23a, and the third insulating layer 24c is sandwiched between the two. Furthermore, the resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c can also be controlled within a specific range. In this invention, the ratio of the resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c is defined as x:y:z. x, y, and z are each between 1 and 1.1. When x, y, and z are each between 1 and 1.1, the heater can be applied with a voltage of 43 volts (V) or higher without burning out. For example, in one embodiment, when the total resistance of the heater is approximately 4 Ω, the resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c are approximately 12 Ω, so x:y:z is approximately 1:1:1. With the aforementioned x:y:z ratio of approximately 1:1:1, the heater can withstand an applied voltage of 43V or higher without burning out. It should be noted that the same components as those described above use the same component symbols and can have the same functions as described above. To avoid redundancy, they will not be repeated here.

[0109] Figure 5 A cross-sectional view of the protective element 50 is shown for one embodiment of the present invention. Figure 5 and Figure 3The main difference lies in the number of heating elements. The protective element 50 comprises a substrate group consisting of multiple substrates (such as a first substrate 21a and a second substrate 21b), while the heater includes a first heating element 23a, a second heating element 23b, and a third heating element 23c, wherein the second heating element 23b is sandwiched between the first substrate 21a and the second substrate 21b. The first substrate 21a has an upper surface S1 and a lower surface S2, while the second substrate 21b has an upper surface and a lower surface opposite to the upper surface. The upper surface of the second substrate 21b directly contacts the lower surface S2 of the first substrate 21a and the second heating element 23b, such that the second heating element 23b completely covers the space between the first substrate 21a and the second substrate 21b. The third heating element 23c is disposed on the lower surface of the second substrate 21b, and the second insulating layer 24b covers the third heating element 23c. A first insulating layer 24a is disposed between the auxiliary electrode 22e and the first heating element 23a, and extends along the y-axis toward the first electrode 22a and the second electrode 22b, then extends to the upper surface S1 of the first substrate 21a. A second insulating layer 24b covers the third heating element 23c, and extends along the y-axis toward the first electrode 22a and the second electrode 22b, then extends to the lower surface of the second substrate 21b. The resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c can also be set within a specific range as described above. It should be noted that the same components as described above use the same component symbols and can have the same functions as described above. To avoid redundancy, these will not be repeated here.

[0110] To better understand the protective element of the present invention, the following verification was performed.

[0111] Table 1

[0112]

[0113] As shown in Table 1, groups E1, E2, and E3 are embodiments E1, E2, and E3 of the protective element 20 of the present invention. In this test, the top view area of ​​the first heating element 23a is the same as the bottom view area of ​​the second heating element 23b, so Table 1 only lists the surface area of ​​one side. That is, the area of ​​a single heating element refers to the second surface area of ​​the first heating element 23a or the third surface area of ​​the second heating element 23b mentioned above. The substrate area refers to the first surface area of ​​the substrate 21 mentioned above. More specifically, the substrate has a first length L1 of 9.5 mm and a first width W1 of 5 mm, and its first surface area is 47.5 mm. 2 The heater resistance refers to the total resistance of the first heating element 23a and the second heating element 23b connected in parallel. Furthermore, the heater is connected to an external power supply and its power can be adjusted to 14W or 43W. It should also be noted that the length, width, and thickness of the fuse 25 used for testing are 3.5mm, 3.5mm, and 0.08mm, respectively.

[0114] In embodiment E1, the length (i.e., the second length L2 or the third length L3) and width (i.e., the second width W2 or the third width W3) of a single heating element are 9.2 mm and 1.8 mm, respectively, resulting in an area of ​​16.56 mm². 2 Therefore, taking the substrate area as 100%, the area of ​​a single heating element in Example E1 is approximately 34.9%. In Example E2, the length and width of the single heating element are 5.65 mm and 1.8 mm, respectively, resulting in an area of ​​10.17 mm². 2 Therefore, taking the substrate area as 100%, the area of ​​a single heating element in Example E1 is approximately 21.4%. In Example E3, the length and width of the single heating element are 2.3 mm and 1.8 mm, respectively, i.e., the area is 4.14 mm². 2 Therefore, taking the substrate area as 100%, the area of ​​a single heating element in Example E1 is approximately 8.7%. Considering the influence of errors and the allowable range of variation, in Examples E1 to E3, the sum of the second and third surface areas can be from 18% to 72%.

[0115] Please continue to refer to Table 1 and also refer to... Figure 6 and Figure 7 . Figure 6 and Figure 7 The heating conditions of the fuse 25 at 14W and 43W are shown. The horizontal axis represents heating time, and the vertical axis represents temperature. At a power of 14W, Embodiments E1 and E2 can reach nearly 350°C and fuse the fuse 25 in about 6 seconds and about 14 seconds, respectively, while Embodiment E3 heats up slowly and cannot fuse the fuse 25 within 15 seconds. This shows that as the surface area of ​​the heating element increases, the melting time can be significantly shortened. However, if the heating element area is too small (i.e., the area of ​​a single heating element is less than 9%), the fuse 25 cannot be melted at low power. Furthermore, considering that other components are still disposed on the substrate 21, the size limit of a single heating element area is about 36%. At a power of 43W, Embodiments E1 to E3 can fuse the fuse 25 in about 1 second to about 5 seconds. Similarly, as the surface area of ​​the heating element increases, the melting time can be significantly shortened. As can be seen from the above, when the area of ​​a single heating element is about 21% to about 35%, both Embodiment E1 and Embodiment E2 can cause the fusible element 25 to fuse under both low and high power. That is, in Embodiment E1 and Embodiment E2, with the first surface area being 100%, the sum of the second and third surface areas is 42% to 70%.

[0116] Table 2

[0117]

[0118] As shown in Table 2, groups C1 and C2 are comparative examples C1 and C2, while groups E4 to E10 are embodiments E4 to E10 of the protective element 20 of the present invention. The difference between the comparative examples and the embodiments lies in the number of heating elements. The area ratio of a single heating element in embodiments E4 to E10 is the same as the area ratio of a single heating element in embodiment E2. Comparative examples C1 and C2 have only a single heating element (e.g., Figure 2c The first heating element 23a (located in the substrate) has a surface area that is approximately 20% of the substrate area. The total resistance of the heaters in all groups is roughly the same, falling within the range of 4Ω to 5Ω. However, in Examples E4 to E10, the first heating element 23a and the second heating element 23b have different resistance ratios. The first heating element 23a has a higher resistance value, while the second heating element 23b has a lower resistance value. Furthermore, the ratio of the resistance value of the first heating element 23a to the resistance value of the second heating element 23b is approximately 1 to 2. Additionally, 15 samples (i.e., protective elements) from each group were tested, and the pass rate refers to the percentage of heaters that did not burn out at a specific power. As shown in Table 2, when the aforementioned ratio is adjusted to 1 to 1.6 (i.e., Examples E4 to E6), the heater can withstand approximately 400W of power without burning out. In other words, in Example E4, when a power of 400W is applied to the heaters of the 15 protection elements 20, all of these heaters operate normally. Similarly, Examples E5 and E6 exhibit the same result. In contrast, Comparative Example C2, at a power of 280W, shows a significantly reduced pass rate to 60%. Clearly, according to... Figure 2c The heater structure (i.e., the design in which the first heating element 23a and the second heating element 23b are disposed on the same substrate) is further adjusted by the present invention to adjust the resistance ratio suitable for this structure and achieve good improvement in power handling.

[0119] Table 3

[0120]

[0121] As shown in Table 3, group C3 is Comparative Example C3, and its structure is the same as that of Comparative Examples C1 and C2. Group E11 is Embodiment E11 of the Protective Element 20 of the present invention, wherein the surface area of ​​each heating element is adjusted to 20% (i.e., the sum of the top view area of ​​the first heating element 23a and the bottom view area of ​​the second heating element 23b is 40%), with the substrate area being 100%. Group E12 is Embodiment E12 of the Protective Element 40 of the present invention, wherein the surface area of ​​each heating element is adjusted to 20% (i.e., the sum of the top view area of ​​the first heating element 23a, the bottom view area of ​​the second heating element 23b, and the top view area of ​​the third heating element 23c is 60%), with the substrate area being 100%. The total resistance of the heaters in all groups is approximately the same, i.e., it falls within the range of 4Ω to 5Ω. In embodiment E11, the resistance values ​​of the first heating element 23a and the second heating element 23b are 9.25Ω and 9.35Ω, respectively, and the heater can withstand a voltage of 23.5V without burning out. In embodiment E12, the resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c are 12.52Ω, 12.45Ω, and 12.54Ω, respectively, and the heater can withstand a voltage of 43V without burning out. The ratio of the resistance values ​​of the first heating element 23a, the second heating element 23b, and the third heating element 23c is approximately 1:1:1. Considering the influence of error and the allowable variation range, the ratio of the resistance values ​​of each heating element can be from 1 to 1.1, and the sum of the top-view area of ​​the first heating element 23a, the bottom-view area of ​​the second heating element 23b, and the top-view area of ​​the third heating element 23c can be appropriately adjusted to 50% to 70%. As can be seen from the above, by setting three heating elements, the voltage withstand capability of the heater can be further improved.

[0122] The technical content and features of this invention have been disclosed above. However, those skilled in the art may still make various substitutions and modifications based on the teachings and disclosures of this invention without departing from the spirit of this invention. Therefore, the scope of protection of this invention should not be limited to the embodiments disclosed, but should include various substitutions and modifications that do not depart from this invention, and is covered by the following claims.

Claims

1. A protection element, comprising: a substrate having an upper surface and a lower surface opposite to the upper surface; a heater comprising a first heating member disposed on the upper surface and a second heating member disposed on the lower surface, wherein: the substrate has a first surface area; the first heating member has a second surface area, and the second heating member has a third surface area; and the sum of the second surface area and the third surface area is 18% to 72% of 100% of the first surface area; and a fuse member disposed above the first heating member, whereby upon occurrence of an overvoltage, the heater heats up and causes the fuse member to melt.

2. The protection element of claim 1, wherein the sum of the second surface area and the third surface area is 42% to 70% of 100% of the first surface area, wherein: the fuse member melts within 15 seconds at a power of 14 W; and the fuse member melts within 5 seconds at a power of 43 W.

3. The protection element of claim 1, wherein a ratio of a resistance value of the first heating member divided by a resistance value of the second heating member is equal to or lower than 2.

4. The protection element of claim 3, wherein the ratio of the resistance value of the first heating member divided by the resistance value of the second heating member is between 1 and 1.

6.

5. The protection element of claim 1, wherein the second surface area of the first heating member is the same as the third surface area of the second heating member.

6. The protection element of claim 1, wherein the second surface area of the first heating member is smaller than the third surface area of the second heating member.

7. The protection element of claim 1, further comprising an electrode set having a first electrode, a second electrode, a third electrode, and a fourth electrode, wherein: the first electrode and the second electrode are disposed opposite to each other on the substrate, and the third electrode and the fourth electrode are disposed opposite to each other on the substrate; two ends of the fuse member are connected to the first electrode and the second electrode, respectively; two ends of the first heating member are connected to the third electrode and the fourth electrode on the upper surface of the substrate, respectively; and two ends of the second heating member are connected to the third electrode and the fourth electrode on the lower surface of the substrate, respectively, whereby the first heating member and the second heating member are connected in parallel.

8. The protection element of claim 7, wherein the electrode set extends inwardly by a distance from an edge of the upper surface or an edge of the lower surface of the substrate, and the distance is 0.1 mm or more.

9. The protection element of claim 7, wherein the electrode set further comprises an auxiliary electrode extending between the fuse member and the first heating member in a direction from the third electrode toward the fourth electrode and connected to the fuse member.

10. The protection element of claim 9, wherein the electrode set further comprises a through hole, wherein: the substrate has a sidewall connecting the upper surface and the lower surface of the substrate; the third electrode does not extend to the sidewall of the substrate and has a first portion and a second portion on the upper surface of the substrate and the lower surface of the substrate, respectively; and the through hole penetrates the upper surface and the lower surface of the substrate such that the first portion and the second portion of the third electrode are electrically connected.

11. The protection element of claim 9, further comprising a first insulating layer and a second insulating layer, wherein: the first insulating layer is disposed between the auxiliary electrode and the first heating element and extends toward the first electrode and the second electrode to the upper surface of the substrate, and the first insulating layer is not in contact with the first electrode, the second electrode, and the fuse element; and the second insulating layer covers the second heating element and extends toward the first electrode and the second electrode to the lower surface of the substrate, and the second insulating layer is not in contact with the first electrode and the second electrode.

12. The protection element of claim 1, wherein the heater further comprises a third heating element, wherein: a ratio of a resistance value of the first heating element, a resistance value of the second heating element, and a resistance value of the third heating element is defined as x:y:z, wherein x, y, and z are each between 1 and 1.

1.

13. The protection element of claim 1, further comprising a cover having a receiving space, wherein: the cover is connected to the substrate such that the fuse element is located in the receiving space and is isolated from an external environment; and the cover does not comprise a heater.

14. The protection element of claim 13, wherein the cover is made of a material selected from the group consisting of polybenzimidazole, polyether ether ketone, polyphenylene sulfide, liquid crystal polymer, polyphthalamide, and combinations thereof, and the substrate is made of a material selected from the group consisting of aluminum oxide, aluminum nitride, zirconium oxide, glass ceramic, and combinations thereof.

15. The protection element of claim 1, further comprising another substrate, wherein the another substrate has an upper surface and a lower surface opposite to the upper surface, and the upper surface of the another substrate directly contacts the lower surface of the substrate and the second heating element such that the second heating element is completely enclosed between the substrate and the another substrate.

16. A protection element, comprising: a substrate having an upper surface and a lower surface opposite to the upper surface; a heater comprising a first heating element, a second heating element, and a third heating element, wherein: the first heating element is disposed on the upper surface, and the second heating element is disposed on the lower surface; the third heating element is disposed above the first heating element, and the third heating element is separated from the first heating element by an insulating layer; the substrate has a first surface area; the first heating element has a second surface area, the second heating element has a third surface area, and the third heating element has a fourth surface area; and a sum of the second surface area, the third surface area, and the fourth surface area is 50% to 70% based on 100% of the first surface area; and a fuse element disposed above the third heating element, whereby upon occurrence of an overvoltage, the heater is heated and causes the fuse element to fuse.

17. The protection element of claim 16, wherein the sum of the second surface area, the third surface area, and the fourth surface area is 60%.

18. The protection element of claim 16, wherein a ratio of the resistance value of the first heating member, the resistance value of the second heating member, and the resistance value of the third heating member is defined as x:y:z, wherein each of x, y, and z is between 1 and 1.

1.

19. The protection element of claim 16, further comprising a cover having a receiving space, wherein: the cover is connected to the substrate such that the fusing member is located in the receiving space and is isolated from an external environment; and the cover does not include a heater.

20. A protection element, comprising: a substrate set having a first substrate and a second substrate, wherein the first substrate has an upper surface and a lower surface opposite the upper surface, and the second substrate is stacked on the lower surface; a heater comprising a first heating member, a second heating member, and a third heating member, wherein: the first heating member is disposed on the upper surface, and the second heating member is disposed on the lower surface, whereby the second heating member directly contacts the second substrate and is sandwiched between the first substrate and the second substrate; the third heating member is disposed below the second substrate; the substrate has a first surface area; the first heating member has a second surface area, the second heating member has a third surface area, and the third heating member has a fourth surface area; and a sum of the second surface area, the third surface area, and the fourth surface area is 50% to 70% based on 100% of the first surface area; and a fusing member disposed above the first heating member, whereby upon occurrence of an overvoltage, the heater is heated and causes the fusing member to fuse.

21. The protection element of claim 20, wherein the sum of the second surface area, the third surface area, and the fourth surface area is 60%.

22. The protection element of claim 20, wherein a ratio of the resistance value of the first heating member, the resistance value of the second heating member, and the resistance value of the third heating member is defined as x:y:z, wherein each of x, y, and z is between 1 and 1.

1.

23. The protection element of claim 20, further comprising a cover having a receiving space, wherein: the cover is connected to the substrate such that the fusing member is located in the receiving space and is isolated from an external environment; and the cover does not include a heater. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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