WO2020138325A1

WO2020138325A1 - Fuse element and protective element

Info

Publication number: WO2020138325A1
Application number: PCT/JP2019/051212
Authority: WO
Inventors: 慎太郎中島; 剛志服部
Original assignee: ショット日本株式会社
Priority date: 2018-12-28
Filing date: 2019-12-26
Publication date: 2020-07-02

Abstract

This protective element (30) comprises: an insulation substrate (33); a plurality of electrodes (34) provided to the insulation substrate (33); a fuse element (35) that is electrically connected to any of the electrodes (34) among the plurality of electrodes (34); and a heating element (38) for heating and causing fusing of the fuse element (35), the heating element (38) being provided to the insulation substrate (33). The fuse element (35) comprises a composite metal material in which there are laminated: a first soluble metal (31), some of the components of which dissolve at a bonding operation temperature; and a second soluble metal (32) having a melting temperature that is lower than the melting temperature of the first soluble metal (31), some of the components of the second soluble metal (32) melting at the bonding operation temperature.

Description

Fuse element and protection element

The present disclosure relates to a fuse element and a protection element including the fuse element.

In recent years, with the rapid spread of small electronic devices such as mobile devices, small and thin protective elements have been used for the protective circuit of the power supply to be mounted. For example, a chip protection element of a surface mount device (SMD (Surface Mount Device)) is preferably used for a protection circuit of a secondary battery pack. As the chip protection element, there is a non-recoverable protection element that detects excessive heat generation caused by an overcurrent of a protected device and operates a fuse under a predetermined condition to interrupt an electric circuit. As a different type of chip protection element, there is a non-recoverable protection element that senses an abnormal increase in ambient temperature and activates a fuse under a predetermined condition to interrupt an electric circuit.

The above protection element causes the resistance element to generate heat by the signal current when the protection circuit detects an abnormality that occurs in the device. The protective element fuses a fuse element made of a fusible alloy material by its heat generation to cut off the circuit, or blows the fuse element due to overcurrent to cut off the circuit, thereby ensuring the safety of the device.

For example, Japanese Patent Laying-Open No. 2013-239405 (Patent Document 1) discloses a protection element in which a resistance element that generates heat in an abnormal state is provided on an insulating substrate such as a ceramic substrate.

In recent years, the fusible alloys that make up the fuse elements of the protection elements described above are becoming lead-free due to the tightening of regulations on chemical substances such as the revised RoHS Directive. For example, there is a fuse element of a lead-free metal composite material described in JP-A-2005-079608 (Patent Document 2). This fuse element is composed of a low melting point metal material that can be melted at a soldering working temperature when surface-mounting a protective element on a circuit board, and a solid phase that can be dissolved in a liquid phase low melting point metal material at the soldering working temperature. Of high melting point metal material. The low melting point metal material and the high melting point metal material of the fuse element are integrally molded. In the above fuse element, the liquid phase low melting point metal material can be held by the solid phase high melting point metal material until the soldering work is completed.

The low melting point metal material and the high melting point metal material of the fuse element are fixed to each other. The fuse element is protected by the liquid phase low melting point metal material while holding the low melting point metal material which is liquidized by the heat of the soldering work so as not to be blown by the solid phase high melting point metal material at the working temperature. It can be bonded to the electrode pattern. Further, the fuse element is prevented from being blown out at the soldering work temperature when the protective element is surface-mounted on the circuit board. This protection element causes a built-in resistance element to generate heat, and the heat causes the high melting point metal material of the fuse element to diffuse or melt into the low melting point metal material which is a medium to perform a fusing operation.

　It is preferable that the electric resistance value of the protective element that functions to cut off the current of the power line is as small as possible because electric energy loss is small. In that respect, it is really convenient to have a high melting point metal material made of silver, which is a low electric resistance material, in the fuse element.

However, since the silver high melting point metal material does not melt at the operating temperature of the protective element, it may remain in a thick film due to insufficient dissolution or diffusion into the low melting point metal material. In this case, in the conventional fuse element, there is a possibility that it takes an extra time for fusing and, in an extreme case, a fusing failure may occur. For these reasons, the refractory metal material cannot be made sufficiently thick in order to reduce the electric resistance value.

Also, with the downsizing and thinning of fuse elements of protection elements, electrodes, substrates, etc., if a thinner fuse element is used, the refractory metal material cannot be thickened. Therefore, when the fuse element is bonded to the electrode pattern, the high melting point metal material may be excessively diffused or dissolved in the liquid phase low melting point metal material to be thinned. In this case, the fuse element may be deformed or the surface of the refractory metal material may be corrugated, which may hinder the attachment of the protective element.

JP, 2013-239405, A Japanese Unexamined Patent Application Publication No. 2015-079608

The present disclosure provides a fuse element capable of more reliably interrupting energization at the time of fuse operation, and a protection element including the protection element, which corresponds to the restriction of chemical substances, the reduction of electric resistance, and the reduction in size and thickness of the protection element. The purpose is to

According to the fuse element of the present disclosure, the first fusible metal in which a part of the components melt at the joining working temperature and the melting temperature lower than the melting temperature of the first soluble metal have the joining working temperature. Provided is a fuse element including a composite metal material in which a second fusible metal in which at least a part of a component is melted is laminated.

The first soluble metal has a predetermined component mixed with the second soluble metal in which a part of the components are melted at the joining operation temperature and a part or all of the components are melted at the same operation temperature, and Gradually approaches the prescribed liquidus temperature. By using the fuse element of the present disclosure, the fuse element can be joined by the reflow method without using a joining material such as solder paste. Since the fuse element is made of fusible metal, there is no fear of fusing residue. Further, the electric resistance of the fuse element can be reduced without using a high melting point metal material made of silver. There is no concern about deformation of the fuse element or waviness on the surface, which contributes to more economical production.

According to a different aspect of the present disclosure, there is provided a protection element including the above fuse element. That is, the protection element according to the present disclosure includes an insulating substrate, a plurality of electrodes provided on the insulating substrate, a fuse element electrically connected to any one of the plurality of electrodes, and the fuse element. And a heating element provided on the insulating substrate for heating and melting. The fuse element has a first fusible metal in which a part of the component melts at a joining working temperature and a melting temperature lower than that of the first fusible metal, and at least a part of the component melts at the joining working temperature. The composite metal material in which the second soluble metal is stacked is provided.

According to the fuse element and the protection element of the present disclosure, it is possible to more reliably cut off the energization during the operation of the fuse.

FIG. 3 is a perspective view showing a fuse element according to an embodiment of the present disclosure. It is an exploded perspective view showing a protection element concerning an embodiment of this indication. The protection element which concerns on embodiment of this indication is shown, (a) is IIIa-IIIa arrow sectional drawing in (b), (b) is IIIb-IIIb arrow sectional drawing in (a), (c) is a bottom view. Is. The protective element which concerns on embodiment of this indication is shown, (a) is IVa-IVa arrow sectional drawing in (b), (b) is IVb-IVb arrow sectional drawing in (a), (c) is a bottom view. Is.

As shown in FIG. 1, the fuse element 10 according to the present disclosure includes a first fusible metal 11 in which some components are melted at a joining working temperature, and a melting temperature lower than the melting temperature of the first fusible metal 11. It is composed of a composite metal material having a temperature and a second fusible metal 12 in which at least a part of the components melt at the above-mentioned joining operation temperature.

The first soluble metal 11 partially dissolves in the second soluble metal 12 at the joining operation temperature. The first fusible metal 11 is diffused or mixed with the second fusible metal 12 in which some or all of the components are melted at the joining operation temperature. By being diffused or mixed, the first soluble metal 11 and the second soluble metal gradually approach the predetermined liquidus temperature.

80Sn-20Ag alloy (liquidus temperature 370°C, solidus temperature 221°C) is an example of the first fusible metal 11 of this fuse element. An example of the second soluble metal 12 is a 60Sn-40Bi alloy (liquidus temperature 175° C., solidus temperature 139° C.). The fuse element 10 is composed of a composite metal material in which the second fusible metal 12 is laminated on the surface of the first fusible metal 11. The solidus temperature and the liquidus temperature depend on Differential Scanning Calorimetry (DSC).

The first fusible metal is not particularly limited, but is, for example, above the solidus temperature of the second fusible metal and below the liquidus temperature of the first fusible metal (however, due to the heat resistance of the peripheral parts, Any lead-free tin-based solder material may be used, in which some of the components are melted at a predetermined joining work temperature (peak temperature is preferably less than 300° C.).

The second fusible metal may be a tin or lead-free tin-based solder material in which some or all of the components melt at the above-mentioned predetermined joining work temperature. The second soluble metal 12 may be a simple metal having a single melting point, a eutectic alloy, or an alloy having a melting range. In addition to the above example, Sn-Cu alloy, Sn-Sb alloy, Sn-Zn alloy, Sn-Al alloy can be used as the first soluble metal. Similarly, as the other second soluble metal, Sn, Sn-Ag alloy, Sn-Ag-Cu alloy, Sn-Ag-Cu-Bi alloy, Sn-Cu alloy, Sn-In alloy, Sn-Ag-In are used. Alloys, Sn-Bi-Ag alloys, Sn-Ag-Bi-In alloys, Sn-Sb alloys, Sn-Zn alloys, Sn-Zn-Bi alloys, Sn-Al alloys and the like can be used.

Both the first soluble metal and the second soluble metal are lead-free metal materials with a high Sn content, and have the drawback of being easily oxidized compared to conventional leaded metal materials. Therefore, at least one of P, Ga, and Ge as an antioxidant trace element is further added to both or either of the first soluble metal and the second soluble metal so as to exceed 3 ppm and less than 300 ppm. What was added to may be used.

When the first fusible metal 11 has a flat plate shape, it is like the fuse element 10 shown in FIG. 1A in which the second fusible metal 12 is laminated on one surface of the plate surface of the first fusible metal 11. It should be set to. Alternatively, the fuse element 15 shown in FIG. 1B may be formed by laminating the second fusible metal 12 on both sides of the plate surface of the first fusible metal 11.

The means for stacking the second soluble metal 12 on the first soluble metal 11 is not particularly limited as long as the second soluble metal 12 can be stacked on the first soluble metal 11. For example, means such as clad (compression bonding), plating, and melt coating can be used.

The fuse element of the present disclosure can be directly placed on an electrode without using a solder paste and bonded to the electrode by a reflow method. Since this fuse element is made of fusible metal, there is no risk of fusing residue. More specifically, a high melting point metal material made of silver has been conventionally used, but the high melting point material made of silver did not melt at the operating temperature of the protective element. In the fuse element of the present embodiment, since the first fusible metal 11 and the second fusible metal 12 are both fusible metals that melt at the operating temperature of the protection element, they are likely to occur in the conventional fuse element. In addition, it is possible to prevent a malfunction in which a part of the fuse element remains without being blown. In this specification, the number before the element symbol in the alloy composition notation of 80Sn-20Ag alloy and the like represents the mass% of the corresponding element.

As shown in FIG. 2, the fuse element according to the present disclosure is melt-bonded to the electrode 24a made of a conductive member provided on the heat-resistant insulating substrate 23 and used as the fuse element 25 of the protection element. The joining work temperature is preferably set to exceed the solidus temperature of the second soluble metal and less than the liquidus temperature of the first soluble metal.

The fuse element 25 and the electrode 24a are joined by the following steps. Flux for bonding is applied to at least the surface of the electrode 24a for bonding the fuse element 25 and at least the surface of the second fusible metal 22 of the fuse element 25. The fuse element 25 is placed so that the second fusible metal 22 contacts the electrode 24a. The fuse element 25 and the insulating substrate 23 are heated to the above-mentioned bonding work temperature to melt a part of the first fusible metal 21 and a part or all of the second fusible metal 22 to form the electrode 24a. The fuse element 25 is joined to.

After that, at least the fuse element 25 is coated with the fusing flux for operation, and the fuse element 25 coated with the fusing flux is covered with the insulating substrate 23 by the cap-shaped lid 26 and packaged, and the protection element 20 is assembled.

The 80Sn-20Ag alloy (liquidus temperature 370° C., solidus temperature 221° C.) is an example of the first fusible metal 21 of the fuse element 25. An example of the second soluble metal 22 is a 60Sn-40Bi alloy (liquidus temperature 175° C., solidus temperature 139° C.). In the case of this example, as a result of the above-mentioned joining work, in the first soluble metal 21, a part of the component is melted at the above-mentioned joining work temperature and a part or all of the component is melted at the same joining work temperature. The fusible metal 22 is diffused or mixed with each other. By being diffusively mixed, the first soluble metal 21 and the second soluble metal 22 gradually approach the predetermined liquidus temperature.

In the first soluble metal 21, Sn migrates from the side of the second soluble metal 22 due to liquid phase diffusion and approaches an equilibrium state, so the Sn component increases, and the Ag concentration also diffuses to the second soluble metal 22. To decrease. As a result, the Ag concentration in the first soluble metal 21 relatively decreases, and the liquidus temperature decreases from the initial 370° C. toward the solidus temperature 221° C.

On the other hand, in the second soluble metal 22, Sn moves toward the first soluble metal 21 side due to the dissolution and diffusion of the first soluble metal 21 and approaches the equilibrium state, so the Sn component decreases and the Bi concentration increases. Also moves to the first soluble metal 21 due to diffusion and decreases. As a result, in the second soluble metal 22, the Bi concentration relatively increases and the liquidus temperature decreases toward the solidus temperature of 139°C. That is, the fuse element is joined, the equilibrium movement of the Sn component, which is the common element of the first soluble metal 21 and the second soluble metal 22, and the mutual diffusion of Ag and Bi, which are different elements, on the mutual sides. Is used to reduce the difference between the liquidus temperature and the solidus temperature of each other, and the fuse operating temperature range is self-adjusted.

In the above fuse element, the solid pure silver coating of the conventional fuse element can be melted faster than the Sn-based lead-free solder. Further, since the silver coating is not used, there is no fear of sulfidation corrosion, silver migration, and fusing failure due to the residual silver coating.

The protection element 20 according to the present disclosure uses the above fuse element, and as shown in FIG. 2, includes an insulating substrate 23, a plurality of electrodes 24a and 24b provided on the insulating substrate 23, and electrodes 24a and 24b. Among them, a fuse element 25 electrically connected to a predetermined electrode (24a in FIG. 2) and a heating element (FIG. 2) provided on the insulating substrate 23 for heating and melting the fuse element 25 and electrically connected to the predetermined electrode. Is disposed on the back surface of the insulating substrate 23). The fuse element 25 has a first fusible metal 21 in which a part of the component melts at the joining operation temperature and a melting range of a temperature lower than that of the first fusible metal 21 and has at least the component at the joining operation temperature. It is made of a composite metal material in which a second fusible metal 22 partially melted is laminated.

The first fusible metal 21 of the fuse element 25 preferably has a liquidus temperature lower than the peak temperature of the heating element (maximum temperature when the heating element generates heat). Thereby, even if a part of the first fusible metal 21 remains without being dissolved in the second fusible metal 22, the first fusible metal 21 is melted by the heat generating element and the fuse element 25 is removed. Can be blown out.

As shown in FIG. 1A, a fuse element 10 of Example 1 according to the present disclosure is made of an alloy plate of 70Sn-30Ag alloy (liquidus temperature 415° C., solidus temperature 221° C.) having a thickness of 80 μm. The first fusible metal 11 and the second fusible metal 12 made of an alloy plate of a 60 μm thick 60Sn-40Bi alloy (liquidus temperature 175° C., solidus temperature 139° C.) are laminated with a clad. It is made of composite metal material.

In addition to this, the fuse element 10 shown in FIG. 1A has a first fusible element made of an alloy plate of 67Sn-33Ag alloy (liquidus temperature 416° C., solidus temperature 220° C.) having a thickness of 65 μm. A composite metal material in which a metal 11 and a second fusible metal 12 made of an alloy plate of 30Sn-70Bi alloy (liquidus temperature 173° C., solidus temperature 139° C.) having a thickness of 25 μm are laminated by a clad are also available. Available.

As shown in FIG. 1B, the fuse element 15 of Example 2 according to the present disclosure is made of an alloy plate of 80 μm thick 80Sn-20Ag alloy (liquidus temperature 370° C., solidus temperature 221° C.). On the upper and lower surfaces of the first fusible metal 11, which is made of clad, a second fusible metal 12 made of an alloy plate of a 60Sn-40Bi alloy (liquidus temperature 175°C, solidus temperature 139°C) having a thickness of 5 μm is clad. It is composed of three layers of composite metal material laminated by. Since the fuse element 15 is provided with the second fusible metal 12 on the upper and lower surfaces of the first fusible metal 11, the directionality of the front and back is lost, so that the fuse element plate may not be erroneously placed during the process of assembling the protection element. Can be prevented.

The fuse element of Example 1 or Example 2 is bonded to an Ag alloy electrode 24a provided on the surface of an alumina/ceramic insulating substrate 23 as shown in FIG. 2, respectively. The protection element of Example 4 is formed.

In the protection element, the electrode 24a of the insulating substrate to which the bonding flux is applied in advance and the second fusible metal 22 of the fuse element 25 are placed in contact with each other. It is passed through a reflow furnace so that the temperature profile has a residual heat temperature of 110 to 130° C., a residence time of 70 seconds, a residence time of 150° C. or higher for 30 seconds, and a peak temperature of 170° C. As a result, a part of the first soluble metal 21 is melted, a part or all of the second soluble metal 22 is melted, and the Sn phases of the common elements are mutually diffused to asymptotically approach an equilibrium state. At the same time, the fuse element 25 is bonded to the electrode 24a by the molten second fusible metal 22. After the fuse element 25 is bonded to the electrode 24a, a fusing flux is applied to the fuse element 25. The fuse element 25 together with the insulating substrate 23 is covered with a cap-shaped lid 26 made of heat-resistant plastic, and the cap-shaped lid 26 and the insulating substrate 23 are fixed with an epoxy resin to form the protective element 20.

The protection element of Example 3 according to the present disclosure is a protection element 30 using the fuse element of Example 1 or Example 2. As shown in FIG. 3, an insulating substrate 33 made of alumina ceramics and an insulating substrate 33 are used. The plurality of Ag alloy pattern electrodes 34 provided on the upper and lower surfaces, the resistance heating element 38 electrically connected to the pattern electrodes 34 and provided on the lower surface of the insulating substrate 33, and the pattern electrode 34 on the upper surface of the insulating substrate 33 are electrically connected. And a cap-shaped lid body 36 made of liquid crystal polymer fixed to an insulating substrate so as to cover the upper portion of the fuse element 35. The fuse element 35 includes a first fusible metal 31 made of an alloy plate of 70Sn-30Ag alloy (liquidus temperature 415° C., solidus temperature 221° C.) having a thickness of 80 μm and 60Sn-40Bi alloy having a thickness of 10 μm. The second fusible metal 32 made of an alloy plate having a liquidus temperature of 175° C. and a solidus temperature of 139° C. is laminated by a clad to form a composite metal material. The pattern electrode 34 has an Ag alloy half through hole 37 that electrically connects the pattern electrodes 34 on the upper and lower surfaces of the substrate.

Although not particularly shown, the surface of the resistance heating element of Example 3 is overglaze made of a glass material. The heating element 38 of the protection element of the third embodiment is provided on a substrate surface (lower surface) different from the substrate surface (upper surface) of the insulating substrate 33 on which the fuse element 35 is provided.

Since the peak temperature of the heating element 38 used in Example 3 is 430° C., for example, the liquidus temperature of the first soluble metal 31 is 415° C. and the liquidus temperature of the second soluble metal 32 is 175° C. Is also high. As a result, even if the first fusible metal 31 remains in the second fusible metal 32 without being melted, the first fusible metal 31 is melted by the heat of the heating element 38. As a result, malfunction of the protection element can be avoided.

The protection element 40 of the fourth embodiment according to the present disclosure is a modification of the protection element of the third embodiment, and is a protection element that uses the fuse element of the first or second embodiment. As shown in FIG. 4, an insulating substrate 43 of alumina ceramics, a plurality of Ag alloy pattern electrodes 44 provided on the upper and lower surfaces of the insulating substrate 43, and an upper surface of the insulating substrate 43 electrically connected to the pattern electrodes 44. The resistance heating element 48, the fuse element 45 which is in contact with the resistance heating element 48 and is electrically connected to the pattern electrode 44 on the upper surface of the insulating substrate 43, and the fuse element 45 is covered and fixed to the insulating substrate 43. And a cap-shaped lid 46 made of liquid crystal polymer.

The fuse element 45 is composed of an 80 μm thick 80Sn-20Ag alloy (liquidus temperature 370° C., solidus temperature 221° C.) alloy plate 41 and a 10 μm thick 60Sn-40Bi alloy. It is composed of a composite metal material in which a second soluble metal 42 made of an alloy plate having a liquidus temperature of 175° C. and a solidus temperature of 139° C. is laminated by a clad. The pattern electrode 44 has a half through hole 47 of Ag alloy that electrically connects the pattern electrodes 44 on the upper and lower surfaces of the substrate.

Since the peak temperature of the heating element 48 used in Example 4 is 400° C., for example, the liquidus temperature of the first soluble metal 41 is 370° C. and the liquidus temperature of the second soluble metal 42 is 175° C. Is also high. As a result, even if the first fusible metal 41 does not dissolve in the second fusible metal 42 and remains, for example, the first fusible metal 41 is melted by the heat of the heating element 48. As a result, malfunction of the protection element can be avoided.

Although not particularly shown, the surface of the resistance heating element 48 of Example 4 is overglaze made of a glass material. The heating element 48 of the protection element of the fourth embodiment is provided on the same substrate surface (upper surface) as the substrate surface (upper surface) of the insulating substrate 43 on which the fuse element 45 is provided.

In the protection elements of Examples 3 and 4, the wiring means for electrically connecting the pattern electrodes on the upper and lower surfaces of the insulating substrate is a conductor through hole penetrating the substrate instead of the half through hole, or a surface wiring by a flat electrode pattern. You may change it.

In order to improve the wettability to the electrode, the Sn-Bi alloy forming the second fusible metal of each of Examples 1 to 4 was changed to a Sn-Bi-Ag alloy in which Ag was further added to the Sn-Bi alloy. You may change it.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

The fuse element made of the composite metal material of the present invention can be incorporated and mounted in the protection element by the entire heating and melting such as reflow. The protective element using this fuse element is soldered and mounted on the electric circuit board by reflow soldering together with other surface mount components, and can be used for a protective device for a secondary battery such as a battery pack.

10, 15, 25, 35, 45 fuse elements, 11, 21, 31, 41 first fusible metal, 12, 22, 32, 42 second fusible metal, 20, 30, 40 protection element, 23, 33, 43 insulating substrate, 24a, 24b, 34, 44 electrode, 26, 36, 46 lid, 37, 47 half through hole, 38, 48 heating element.

Claims

A first fusible metal in which a part of the component melts at the joining work temperature and a melting temperature lower than the melting temperature of the first fusible metal, and at least a part of the component melts at the joining work temperature A fuse element comprising a composite metal material in which a second fusible metal is laminated.
Part of the components of the first fusible metal melts at a joining working temperature that is higher than the solidus temperature of the second fusible metal and lower than the liquidus temperature of the first fusible metal. The fuse element according to claim 1, which is a lead-free tin-based solder material.
A part or all of the components of the second soluble metal exceed the solidus temperature of the second soluble metal and are less than the liquidus temperature of the first soluble metal at a bonding operation temperature. The fuse element according to claim 1 or 2, wherein is a molten tin or lead-free tin-based solder material.
The first fusible metal is any metal selected from the group of Sn-Ag alloy, Sn-Cu alloy, Sn-Sb alloy, Sn-Zn alloy and Sn-Al alloy. The fuse element according to claim 3.
The second soluble metal is Sn, Sn-Ag alloy, Sn-Ag-Cu alloy, Sn-Ag-Cu-Bi alloy, Sn-Cu alloy, Sn-Bi alloy, Sn-In alloy, Sn-Ag. --In alloy, Sn--Bi--Ag alloy, Sn--Ag--Bi--In alloy, Sn--Sb alloy, Sn--Zn alloy, Sn--Zn--Bi alloy, and Sn--Al alloy The fuse element according to any one of claims 1 to 4, which is a metal.
The fuse element according to claim 4, wherein the first fusible metal is a Sn-Ag alloy, and the Ag content of the Sn-Ag alloy is 20% by mass or more and 30% by mass or less.
The fuse element according to claim 4, wherein the first fusible metal is an 80Sn-20Ag alloy or a 70Sn-30Ag alloy.
The fuse element according to claim 5, wherein the second fusible metal is a Sn-Bi alloy, and a Bi content of the Sn-Bi alloy is 40% by mass or more and 70% by mass or less.
The fuse element according to claim 5, wherein the second fusible metal is a 60Sn-40Bi alloy or a 30Sn-70Bi alloy.
An insulating substrate,
A plurality of electrodes provided on the insulating substrate,
A fuse element electrically connected to any one of the plurality of electrodes,
A heating element provided on the insulating substrate to heat and fuse the fuse element;
The fuse element has a first fusible metal in which a part of the component melts at a joining working temperature and a melting temperature lower than a melting temperature of the first fusible metal, and at least the component at a joining working temperature. A protective element comprising a composite metal material in which a second fusible metal part of which melts is laminated.
The protection element according to claim 10, wherein the heating element is provided on a substrate surface different from the substrate surface of the insulating substrate on which the fuse element is provided.
The protection element according to claim 10, wherein the heating element is provided on the same substrate surface as the substrate surface of the insulating substrate on which the fuse element is provided.
Part of the components of the first fusible metal melts at a joining working temperature that is higher than the solidus temperature of the second fusible metal and lower than the liquidus temperature of the first fusible metal. 13. The protective element according to claim 10, which is a lead-free tin-based solder material.
A part or all of the components of the second soluble metal exceed the solidus temperature of the second soluble metal and are less than the liquidus temperature of the first soluble metal at a bonding operation temperature. The protective element according to any one of claims 10 to 13, wherein is a molten tin or lead-free tin-based solder material.
11. The first soluble metal is any metal selected from the group consisting of Sn—Ag alloy, Sn—Cu alloy, Sn—Sb alloy, Sn—Zn alloy and Sn—Al alloy. The protection element according to claim 14.
The second soluble metal is Sn, Sn-Ag alloy, Sn-Ag-Cu alloy, Sn-Ag-Cu-Bi alloy, Sn-Cu alloy, Sn-Bi alloy, Sn-In alloy, Sn-Ag. --In alloy, Sn--Bi--Ag alloy, Sn--Ag--Bi--In alloy, Sn--Sb alloy, Sn--Zn alloy, Sn--Zn--Bi alloy, and Sn--Al alloy The protection element according to any one of claims 10 to 15, which is a metal.
The protection element according to claim 15, wherein the first fusible metal is a Sn-Ag alloy, and the Ag content of the Sn-Ag alloy is 20% by mass or more and 30% by mass or less.
The protection element according to claim 15, wherein the first fusible metal is an 80Sn-20Ag alloy or a 70Sn-30Ag alloy.
The protective element according to claim 16, wherein the second fusible metal is a Sn-Bi alloy, and the Bi content of the Sn-Bi alloy is 40% by mass or more and 70% by mass or less.
The protection element according to claim 16, wherein the second fusible metal is a 60Sn-40Bi alloy or a 30Sn-70Bi alloy.
The protective element according to any one of claims 10 to 20, wherein the liquidus temperature of the first fusible metal is lower than the peak temperature of the heating element.