JP6707377B2 - Protective element - Google Patents

Description

The present invention relates to a protection element which is mounted on a current path and blows a fuse element by heating with a heater to cut off the current path when a current exceeding a rating flows.

2. Description of the Related Art Conventionally, a protection element has been used that blows a fuse element by heating with a heater when a current exceeding a rating flows to cut off the current path. Such a protective element is formed on a functional chip in which electrodes and fuse elements are mounted on an insulating substrate, and a surface mount type in which this chip is mounted on a circuit board is known.

In the protection element as described above, the fuse element is blown by energizing and heating the heater based on the signal from the external circuit, so it can be used as a switch that cuts off the current path at the timing based on the control of the external circuit. Is possible. Such a protection element is used as a protection circuit for a secondary battery such as a lithium ion battery.

2. Description of the Related Art In recent years, the number of secondary battery applications such as lithium-ion batteries that require a large current output, such as electric-assisted bicycles and electric tools, has increased, and the rated current of a protection circuit has increased, and a fuse that can withstand a large current Elements have come into use.

The technique described in Patent Document 1 discloses a protection element using a fuse element that can handle a large current.

JP, 2005-035281, A

However, in the technique described in Patent Document 1, a current path that conducts from the front surface to the back surface of the insulating substrate is not clearly specified, but in order to cope with a large current, only the conductive path on the side surface of the insulating substrate is used. It is necessary to reduce the resistance value by forming a through hole that has a large resistance value and directly connects the front and back of the insulating substrate, or a current path in which the through hole is filled with a conductor.

Further, in the technique described in Patent Document 1, when a through hole that directly connects the front and back of the insulating substrate or a current path in which the through hole is filled with a conductor is formed, the heat from the heater generates the current. It is difficult to concentrate and transfer the heat to the fuse element due to diffusion through the route, which deteriorates the quick-melting property of the fuse element.

Therefore, it is an object of the present invention to provide a protection element that can handle a large current and that efficiently transfers heat from a heater to a fuse element without impeding miniaturization, and that is excellent in rapid fusing property.

In order to solve the above-mentioned problems, a protection element according to the present invention includes an insulating substrate, a first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other, and a heating element. And a heating element lead-out electrode electrically connected to the heating element, the first surface electrode, the second surface electrode and the heating element lead-out electrode, and is melted by heating the heating element And a fuse element for interrupting a current path between the second front surface electrode, a first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate, and a first side electrode formed on a side surface of the insulating substrate. The front surface electrode and the second front surface electrode are connected to the first back surface electrode and the second back surface electrode, respectively, and the first front surface electrode and the second front surface electrode are connected between the front surface and the back surface of the insulating substrate. Of the first side surface conductive portion and the second side surface conductive portion forming all current paths connecting the back surface electrode and the second back surface electrode of A concave portion is provided on a side surface corresponding to the surface electrode, and a first side surface conductive portion and a second side surface conductive portion are formed in the concave portion, and the first side surface conductive portion and the second side surface conductive portion are respectively formed on the insulating substrate. The first side surface conductive portion and the second side surface conductive portion are provided on the side surfaces facing each other, and are provided at positions offset from the positions facing each other .
Further, the protection element according to the present invention includes an insulating substrate, a first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to be opposed to each other, a heating element, and an electrical heating element. Of the heating element extraction electrode connected to the first surface electrode, the second surface electrode and the heating element extraction electrode, and is melted by heating the heating element, A fuse element for interrupting a current path between them, a first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate, and a first surface electrode and a second surface formed on the side surface of the insulating substrate. The electrodes are respectively connected to the first back surface electrode and the second back surface electrode, and the first front surface electrode and the second front surface electrode and the first back surface electrode and the second back surface electrode are provided between the front surface and the back surface of the insulating substrate. The insulating substrate includes a first side surface conductive portion and a second side surface conductive portion that form all current paths connecting to the back surface electrode, and the insulating substrate is provided on a side surface corresponding to the first surface electrode and the second surface electrode. A concave portion is provided, and a first side surface conductive portion and a second side surface conductive portion are formed in the concave portion, and the first side surface conductive portion and the second side surface conductive portion are provided on the same side surface of the insulating substrate. is there.
Further, the protection element according to the present invention includes an insulating substrate, a first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to be opposed to each other, a heating element, and an electrical heating element. Of the heating element extraction electrode connected to the first surface electrode, the second surface electrode and the heating element extraction electrode, and is melted by heating the heating element, A fuse element for interrupting a current path between them, a first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate, and a first surface electrode and a second surface formed on the side surface of the insulating substrate. The electrodes are respectively connected to the first back surface electrode and the second back surface electrode, and the first front surface electrode and the second front surface electrode and the first back surface electrode and the second back surface electrode are provided between the front surface and the back surface of the insulating substrate. The insulating substrate includes a first side surface conductive portion and a second side surface conductive portion that form all current paths connecting to the back surface electrode, and the insulating substrate is provided on a side surface corresponding to the first surface electrode and the second surface electrode. A concave portion is provided, a first side surface conductive portion and a second side surface conductive portion are formed in the concave portion, and a plurality of first side surface conductive portions or second side surface conductive portions are provided.

Further, in order to solve the above-mentioned problems, the protection element according to the present invention includes an insulating substrate, and a first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other, The heating element, the heating element lead-out electrode electrically connected to the heating element, and the first surface electrode, the second surface electrode, and the heating element lead-out electrode are connected and melted by heating the heating element, A fuse element for interrupting a current path between the front surface electrode and the second front surface electrode, a first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate, and a hole penetrating the insulating substrate. , A first front surface electrode and a second front surface electrode, and a first back surface electrode and a second back surface electrode, respectively, which are connected to each other to form a conductive path between the front surface and the back surface of the insulating substrate. And a second penetrating conductive portion, wherein the first surface electrode and the second surface electrode project into a region in contact with the first penetrating conductive portion and the second penetrating conductive portion. And a second surface convex portion, respectively.

According to the present invention, by disposing the current path for conducting the front surface and the back surface of the insulating substrate only on the side surface of the insulating substrate, the heat from the heater is concentrated in the fuse element without being diffused into the through holes. It is possible to improve the quick fusing property of the fuse element. Even when a through hole is provided as a through hole for a current path that connects the front surface and the back surface of the insulating substrate, only the surface protrusion protruding from the surface electrode to the periphery of the current path is formed to reduce the surface electrode area. By making it small, it is possible to prevent the heat diffusion to the surface electrode and to concentrate and transfer the heat to the fuse element, so that the rapid fusing property of the fuse element can be improved.

FIG. 1 is a plan view showing a fuse element as seen through the fuse element according to the first exemplary embodiment. FIG. 2 is a cross-sectional view taken along the line A-A′ shown in FIG. FIG. 3 is a schematic diagram for explaining the shape of the first side surface conductive portion, and is a plan view of the first front surface electrode viewed from the upper surface, and FIG. 3A shows a semicircular shape. 3B shows a rectangular groove shape, FIG. 3C shows a semi-elliptical hole shape, and FIG. 3D shows a wave groove shape. FIG. 4 is an equivalent circuit diagram for explaining the circuit configuration of the fuse element. FIG. 4(A) shows a state before the operation of the fuse element, and FIG. 4(B) shows that the fuse element melts after the operation of the fuse element. Shows the state of being done. FIG. 5 is a plan view showing a state in which the fuse element in FIG. 1 is activated and the fuse element is melted. FIG. 6 is a cross-sectional view taken along the line A-A′ shown in FIG. FIG. 7 is a plan view showing a fuse element of the fuse element according to the first modification as seen through the fuse element. FIG. 8 is a plan view showing a fuse element of the fuse element according to the second modification, as seen through the fuse element. FIG. 9 is a plan view showing a fuse element of a fuse element according to a third modification in a transparent manner. FIG. 10 is a plan view showing a fuse element of a fuse element according to a fourth modification as seen through. FIG. 11 is a plan view showing the fuse element of the fuse element according to the second embodiment as seen through the fuse element. FIG. 12 is a plan view of the fuse element in FIG. 11 viewed from the back surface. FIG. 13 is a cross-sectional view taken along the line A-A′ shown in FIG. 11. FIG. 14 is a plan view showing a state in which the fuse element in FIG. 11 is activated and the fuse element is melted. FIG. 15 is a cross-sectional view taken along the line A-A′ shown in FIG.

Hereinafter, as a protection element to which the present invention is applied, a fuse element will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Moreover, the drawings are schematic, and the ratios of the respective dimensions may differ from the actual ones. Specific dimensions should be judged in consideration of the following description. Further, it is needless to say that the drawings include portions in which dimensional relationships and ratios are different from each other.

[First Embodiment]
As shown in FIGS. 1 and 2, the fuse element 1 according to the first embodiment is surface-mounted by reflow on a circuit board such as a protection circuit of a lithium-ion secondary battery, so that the lithium-ion secondary The fuse element 7 is incorporated in the charge/discharge path of the battery.

When a large current that exceeds the rating of the fuse element 1 flows, this protection circuit cuts off the current path by fusing the fuse element 7 by self-heating (Joule heat). Further, in this protection circuit, the heating element 5 is energized at a predetermined timing by a current control element provided on a circuit board or the like on which the fuse element 1 is mounted, and the fuse element 7 is melted by the heat generated by the heating element 5. The current path can be interrupted. 1 is a plan view showing the fuse element 1 with the case omitted, and FIG. 2 is a sectional view of the fuse element 1.

[Fuse element]
As shown in FIGS. 1 and 2, the fuse element 1 includes an insulating substrate 2, a first surface electrode 3 and a second surface electrode 4 provided on a surface 2a of the insulating substrate 2 so as to face each other. , The heating element 5, the heating element lead-out electrode 6 electrically connected to the heating element 5, the first surface electrode 3, the second surface electrode 4 and the heating element lead-out electrode 6, and are connected to each other. A fuse element 7 that melts by heating and interrupts the current path between the first front surface electrode 3 and the second front surface electrode 4, and the first back surface electrode 3a and the second back surface electrode 3a provided on the back surface 2b of the insulating substrate 2. Of the back surface electrode 4a and the side surface of the insulating substrate 2 are connected to the first front surface electrode 3 and the second front surface electrode 4 and the first back surface electrode 3a and the second back surface electrode 3b, respectively. A second front surface electrode 3 and a second back surface electrode 4 which connect all the current paths connecting the first front surface electrode 3 and the second front surface electrode 4 to the first back surface electrode 3a and the second back surface electrode 3b. The first side surface conductive portion 3b and the second side surface conductive portion 4b are provided.

Further, the fuse element 1 is provided on the surface 2 a of the insulating substrate 2 and at both ends of the heating element 5 and the insulator 9 that covers the heating element 5 and prevents contact between the heating element 5 and the heating element lead-out electrode 6. A first heating element electrode 10 and a second heating element electrode 11 are provided. One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11, and the other is connected to a midway portion of the fuse element 7.

In addition, the fuse element 1 includes a third back surface electrode 10a provided on the back surface 2b of the insulating substrate 2 and a side surface of the insulation substrate 2 and includes a first heating element electrode 10 and a third back surface electrode 10a. It is provided with a third side surface conductive portion 10b which is connected and serves as all conductive paths between the front surface 2a and the back surface 2b of the insulating substrate 2.

Here, all current paths between the front surface 2a and the back surface 2b of the insulating substrate 2 are the first front surface electrode 3, the second front surface electrode 4, the first heating element electrode 10, and the first back surface. A current path connecting the electrode 3a, the second back surface electrode 4a, and the third back surface electrode 10a is shown. Therefore, it means that the current path is formed only on the side surface of the insulating substrate 2. In other words, the fuse element 1 has a structure in which no current path is formed except on the side surface of the insulating substrate 2.

Specifically, the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the third side surface conductive portion 10b in the fuse element 1 are respectively the first side surface 2c, the second side surface 2d, and the second side surface 2d of the insulating substrate 2. It is provided on the third side surface 2e.

Since the fuse element 1 has no current path other than the side surface of the insulating substrate 2, it does not have a current path such as a through hole in the central portion of the insulating substrate. Therefore, heat generated from the heating element 5 is generated in the central portion of the insulating substrate. The fuse element 7 can be concentrated and overheated without being diffused by a through hole or the like.

[Insulation substrate]
The insulating substrate 2 is formed in a rectangular shape by using an insulating member such as alumina, glass ceramics, mullite, or zirconia. In addition, the insulating substrate 2 may be made of a material used for a printed wiring board such as a glass epoxy board or a phenol board. The side surfaces of the insulating substrate 2 facing each other are a first side surface 2c and a second side surface 2d, and the remaining side surfaces are a third side surface 2e and a fourth side surface 2f facing each other.

[First surface electrode and second surface electrode]
The first surface electrode 3 and the second surface electrode 4 are opened on the surface 2a of the insulating substrate 2 by being spaced apart from each other in the vicinity of opposite side edges, and the fuse element 7 is mounted. As a result, they are electrically connected via the fuse element 7. Further, in the first surface electrode 3 and the second surface electrode 4, a large current exceeding the rating flows into the fuse element 1, the fuse element 7 is melted by self-heating (Joule heat), or the heating element 5 is energized. As a result, heat is generated and the fuse element 7 is melted, and the current path is cut off.

As shown in FIGS. 1 and 2, the first front surface electrode 3 and the second front surface electrode 4 are inserted through half through holes provided in the first side surface 2c and the second side surface 2d of the insulating substrate 2, respectively. Are connected to the first back surface electrode 3a and the second back surface electrode 4a which are external connection electrodes provided on the back surface 2b. The fuse element 1 is connected to a circuit board on which an external circuit is formed via the first back surface electrode 3a and the second back surface electrode 4a, and constitutes a part of a current path of the external circuit. Therefore, the half through holes provided in the first side surface 2c and the second side surface 2d form the first side surface conductive portion 3b and the second side surface conductive portion 4b.

The first surface electrode 3 and the second surface electrode 4 can be formed by using a general electrode material such as Cu or Ag. On the surfaces of the first surface electrode 3 and the second surface electrode 4, a coating film such as Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating is formed by a known method such as plating treatment. It is preferably coated. Thereby, the fuse element 1 can prevent the first surface electrode 3 and the second surface electrode 4 from being oxidized, and can prevent the fluctuation of the rating due to the increase of the conduction resistance.

Further, when the fuse element 1 is reflow-mounted, when the low melting point metal layer is formed on the connecting solder for connecting the fuse element 7 or the outer layer of the fuse element 7, the low melting point metal is melted and It is possible to prevent the front surface electrode 3 and the second front surface electrode 4 from being corroded (soldered).

[Heating element]
The heating element 5 is a conductive member that generates heat when energized, and is made of, for example, nichrome, W, Mo, Ru, Cu, Ag, or an alloy containing these as main components. The heating element 5 is formed by mixing powders of these alloys, compositions, or compounds with a resin binder or the like, forming a paste, and patterning the paste on the insulating substrate 2 using a screen printing technique, and firing the paste. And the like. In addition, the heating element 5 has one end connected to the first heating element electrode 10 and the other end connected to the second heating element electrode 11.

In the fuse element 1, an insulating material 9 is arranged so as to cover the heating element 5 formed on the surface 2a of the insulating substrate 2, and a heating element lead-out electrode is provided so as to face the heating element 5 via the insulating element 9. 6 is formed. Insulators may be laminated between the heating element 5 and the insulating substrate 2 in order to efficiently transfer the heat of the heating element 5 to the fuse element 7. As the insulator 9, for example, a glass material can be used.

One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11 and is connected to one end of the heating element 5 via the second heating element electrode 11. The second heating element electrode 11 is formed on the surface 2a side of the insulating substrate 2, and the first heating element electrode 10 is formed from the surface 2a side of the insulating substrate 2 to the third side surface 2e side. .. Further, the first heating element electrode 10 is connected to the third back surface electrode 10a formed on the back surface 2b of the insulating substrate 2 through the half through hole formed in the third side surface 2e. Therefore, the half through hole formed on the third side surface 2e constitutes the third side surface conductive portion 10b.

When the fuse element 1 is mounted on the circuit board, the heating element 5 is connected to the external circuit formed on the circuit board via the third back surface electrode 10a. Then, the heating element 5 is energized via the third back surface electrode 10a at a predetermined timing to cut off the current path of the external circuit and generates heat, so that the first front surface electrode 3 and the second front surface electrode 4 are separated from each other. The fuse element 7 connected can be blown. Further, the heating element 5 stops its heat generation because the fuse element 7 is melted and the current path thereof is also cut off.

[Heating element extraction electrode]
The heating element lead-out electrode 6 can be formed by using a general electrode material such as Cu or Ag. Further, it is preferable that a film such as Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating is coated on the surface of the heating element lead-out electrode 6 by a known method such as plating.

[First heating element electrode and second heating element electrode]
The first heating element electrode 10 and the second heating element electrode 11 are opened on the surface 2a of the insulating substrate 2 by arranging the side edges adjacent to each other so as to be spaced apart from each other, and the heating element 5 is mounted. By doing so, they are electrically connected via the heating element 5.

The first heating element electrode 10 and the second heating element electrode 11 can be formed by using a general electrode material such as Cu or Ag. Further, on the surfaces of the first heating element electrode 10 and the second heating element electrode 11, a coating film of Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating or the like is formed by a known method such as plating treatment. It is preferably coated by a technique.

Here, the first back surface electrode 3a and the first side surface conductive portion 3b can be formed of the same material as that of the first front surface electrode 3, and the second back surface electrode 4a and the second side surface conductive portion 3b can be formed. The portion 4b can be formed of the same material as the second front surface electrode 4, and the third back surface electrode 10a and the third side surface conductive portion 10b are formed of the same material as the first heating element electrode 10. Shall be able to.

[Fuse element]
The fuse element 7 is made of a material that is quickly melted by the heat generated by the heating element 5, and a low melting point metal such as solder or Pb-free solder containing Sn as a main component can be preferably used.

The fuse element 7 may be made of a high melting point metal such as In, Pb, Ag, Cu or an alloy containing any of these as a main component, or the inner layer may be a low melting point metal layer and the outer layer may be a high melting point metal. It may be a laminated body of a low melting point metal and a high melting point metal such as a metal layer. By containing the high melting point metal and the low melting point metal, even when the reflow temperature exceeds the melting temperature of the low melting point metal and the low melting point metal is melted when the fuse element 1 is reflow-mounted, It is possible to suppress the outflow to the outside and maintain the shape of the fuse element 7. Also during melting, the low-melting point metal melts and thereby erodes (solders) the high-melting point metal, so that the high-melting point metal can be rapidly melted at a temperature equal to or lower than the melting point.

The fuse element 7 is connected to the heating element lead electrode 6, the first surface electrode 3 and the second surface electrode 4 by soldering or the like. The fuse element 7 can be easily connected by reflow soldering. The fuse element 7 is mounted on the heating element lead-out electrode 6 so as to overlap with the heating element lead-out electrode 6 and also to overlap with the heating element 5. In addition, the fuse element 7 connected between the first surface electrode 3 and the second surface electrode 4 melts between the first surface electrode 3 and the second surface electrode 4, and the first surface electrode 3 The gap between the electrode 3 and the second surface electrode 4 is cut off. That is, the fuse element 7 has a central portion supported by the heating element lead-out electrode 6 and a central portion supported by the heating element lead-out electrode 6 serving as a fusing part.

Further, the fuse element 7 is coated with a flux (not shown) in order to prevent oxidation and improve wettability. By holding the flux, the fuse element 7 prevents oxidation of the fuse element 7 and increase in the fusing temperature due to the oxidation, suppresses fluctuations in the fusing characteristics, and enables rapid fusing.

[Side conductive part]
Here, the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 10b will be described in detail.

The first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 10b can be formed by using a general electrode material such as Cu or Ag. Further, on the surfaces of the first side surface conductive portion 3b, the second side surface conductive portion 4b and the second side surface conductive portion 10b, a coating film of Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating, or the like. However, they are preferably coated by a known method such as plating.

Next, the shapes of the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 10b will be described with reference to FIG. In the following, only the first side surface conductive portion 3b will be described, but the second side surface conductive portion 4b and the second side surface conductive portion 10b can have the same shape, and thus the description thereof will be omitted. To do.

The first side-face conductive portion 3b shown in FIG. 3A is formed by forming a semicircular cutout in the insulating substrate 2 to form a concave portion and patterning a conductive material in the concave portion. The first side surface conductive portion 3b is a so-called half through hole, and electrically connects the first front surface electrode 3 and the first back surface electrode 3b between the front surface 2a and the back surface 2b of the insulating substrate 2. ..

The first side surface conductive portion 3b shown in FIG. 3(A) has circular through holes provided between adjacent individual insulating substrates when the insulating substrate 2 is cut out from a mother substrate (not shown), and each of the through holes serves as a boundary. By cutting out the insulating substrate, it can be formed as a semicircular recess. Since the through-hole can be easily created by providing a cylindrical projection on a mold used for forming the mother substrate, the through-hole is easy to manufacture.

It is also possible to form the first side surface conductive portion 3b in another shape. For example, the first side surface conductive portion 3c shown in FIG. 3B has a rectangular groove-shaped cutout in the insulating substrate 2. Is added to form a concave portion, and a conductive material is patterned in the concave portion. The first side surface conductive portion 3c electrically connects the first front surface electrode 3 and the first back surface electrode 3b between the front surface 2a and the back surface 2b of the insulating substrate 2.

In the first side surface conductive portion 3c shown in FIG. 3B, a rectangular through hole is provided between individual insulating substrates adjacent to each other when the insulating substrate 2 is cut out from a mother substrate (not shown), and each of the through holes serves as a boundary. By cutting out the insulating substrate, it can be formed as a rectangular groove-shaped recess. The through hole is easy to manufacture because it can be easily created by providing a rectangular-pillar-shaped projection on a mold for forming the mother substrate.

The first side surface conductive portion 3c shown in FIG. 3(B) has a recessed area larger than that of the first side surface conductive portion 3b shown in FIG. 3(A) on the first side surface 2c of the insulating substrate 2. The width can be wide, and as a result, the width of the current path can be widened to reduce the electric resistance value, which is suitable for handling a large current.

In addition, the first side surface conductive portion 3b can be formed in another shape, and for example, the first side surface conductive portion 3d shown in FIG. A notch is added to form a recess, and a conductive material is patterned in the recess to form the recess. The first side surface conductive portion 3d electrically connects the first front surface electrode 3 and the first back surface electrode 3b between the front surface 2a and the back surface 2b of the insulating substrate 2.

The first side-face conductive portion 3d shown in FIG. 3C is provided with elongated hole-shaped through holes between adjacent individual insulating substrates when the insulating substrate 2 is cut out from a mother substrate (not shown), and the through holes are used as boundaries. By cutting out each insulating substrate, it is possible to form a semi-oblong hole-shaped recess. Since the through-hole can be easily formed by providing a column-shaped projection corresponding to a rectangular hole shape in a mold used for forming the mother substrate, the through-hole is easy to manufacture.

The first side surface conductive portion 3d shown in FIG. 3(C) has a larger recess area on the first side surface 2c of the insulating substrate 2 than the first side surface conductive portion 3b shown in FIG. 3(A). The width can be wide, and as a result, the width of the current path can be widened to reduce the electric resistance value, which is suitable for handling a large current.

Further, the first side surface conductive portion 3b can be formed in another shape. For example, the first side surface conductive portion 3e shown in FIG. A recess is formed by adding a notch, and a conductive material is patterned and formed in this recess. The first side surface conductive portion 3e electrically connects the first front surface electrode 3 and the first back surface electrode 3b between the front surface 2a and the back surface 2b of the insulating substrate 2.

In the first side surface conductive portion 3e shown in FIG. 3D, when the insulating substrate 2 is cut out from a mother substrate (not shown), corrugated elongated hole-shaped through holes are provided between adjacent insulating substrates. By cutting each insulating substrate at the boundary, it is possible to form a groove-shaped recess. Since the through-hole can be easily formed by providing a column-shaped projection corresponding to a wavy elongated hole shape in a mold used for forming the mother substrate, the through-hole is easy to manufacture.

The first side surface conductive portion 3e shown in FIG. 3D has a recessed area larger than that of the first side surface conductive portion 3b shown in FIG. 3A on the first side surface 2c of the insulating substrate 2. The width can be wide, and as a result, the width of the current path can be widened to reduce the electric resistance value, which is suitable for handling a large current.

Summarizing the shape of each recess described above, by forming the side surface of the insulating substrate 2 with a non-planar surface including a curved surface, the area of the recess can be increased, and as a result, the width of the current path can be increased and the electrical resistance value can be increased. It can be said that it is suitable for dealing with a large current.

The fuse element 1 realizes a compact and high-rated protective element. For example, the size of the insulating substrate 2 is as small as about 2 to 3 mm×1 to 2 mm, but the resistance value is 0.5 to High rating of 1 mΩ and 50 to 60 A has been achieved. It is needless to say that the present invention can be applied to protection elements having any size, resistance value and current rating. In this embodiment, the size of the insulating substrate 2 is 2.7 mm×1.8 mm.

The fuse element 1 has a cover member (not shown) mounted on the surface 2a of the insulating substrate 2 to protect the inside and prevent the molten fuse element 7 from scattering. The cover member has a side wall mounted on the surface 2 a of the insulating substrate 2 and a top surface that constitutes the upper surface of the fuse element 1. This cover member can be formed using an insulating member such as thermoplastics, ceramics, or a glass epoxy substrate. Since the characteristic structure of the present invention is the internal structure of the cover member, the description of the cover member will be omitted in the following description.

[Circuit configuration]
Here, the circuit configuration of the fuse element 1 and the interruption operation of the energization path will be described. In the fuse element 1, as shown in FIGS. 1 and 4A, a fuse element 7 is connected from a first surface electrode 3 to a second surface electrode 4, and a heating element is provided in the middle of the fuse element 7. The extraction electrode 6 is connected. The heating element lead-out electrode 6 is connected to the second heating element electrode 11, the heating element 5, and the first heating element electrode 10 in this order on the side opposite to the side connected to the fuse element 7. Therefore, the fuse element 1 includes the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 4b from the first surface electrode 3, the second surface electrode 4, and the first heating element electrode 10, respectively. It can be said that this is a three-terminal element in which the first back surface electrode 3a, the second back surface electrode 4a, and the third back surface electrode 10a connected through the side surface conductive portion 10b are external terminals.

The fuse element 1 is configured so that the current of the main circuit flows from the first surface electrode 3 toward the second surface electrode 4, and when the current flows from the first heating element electrode 10, heat is generated. As shown in FIGS. 5, 6 and 4B, the body 5 generates heat, the fuse element 7 is melted, the melted body 7a is aggregated on the heating body lead electrode 6, and the fuse element 7 is cut. As a result, in the fuse element 1, the current path between the first surface electrode 3 and the second surface electrode 4 is cut off, and the current path to the heating element 5 is also cut off.

[Modification 1]
Next, a modified example of the fuse element 1 described above will be described. Further, the portions substantially similar to those of the fuse element 1 described above are denoted by the same reference numerals, the description thereof will be omitted, and the differences will be described. Further, the equivalent circuit is the same as that described with reference to FIG.

As shown in FIG. 7, in the fuse element 20 according to Modification 1, the first surface electrode 3 extends to the fourth side surface 2f of the insulating substrate 2, the first side surface conductive portion 3b is not provided, and the first surface electrode 3 is provided. provided side conductive portion 3b ₁ of the fourth aspect 2f of the insulating substrate 2, the second surface electrode 4 are extended to the third aspect 2e of the insulating substrate 2, without providing the second side conductive portion 4b, A configuration in which the second side surface conductive portion 4b ₁ is provided on the third side surface 2e of the insulating substrate 2, and the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ are arranged at diagonal positions of the insulating substrate 2. It is what

Although illustration is omitted, in the fuse element 20, the first back surface electrode 3a is extended to the fourth side surface 2f of the insulation substrate 2 on the back surface 2b side of the insulation substrate 2 and the first side surface conductive portion is formed. 3b ₁ and the second back surface electrode 4a extends to the third side surface 2e of the insulating substrate 2 and is connected to the second side surface conductive portion 4b ₁ .

In the fuse element 20, since the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ are arranged at positions far from the heating element 5, the effect of preventing the diffusion of heat from the heating element 5 becomes high, and the fuse It becomes easy to concentrate heat on the element 7.

[Modification 2]
Further, a modified example of the fuse element 1 described above will be described. Further, the portions substantially similar to those of the fuse element 1 described above are denoted by the same reference numerals, the description thereof will be omitted, and the differences will be described. Further, the equivalent circuit is the same as that described with reference to FIG.

As shown in FIG. 8, in the fuse element 30 according to the modified example 2, the first surface electrode 3 is extended to the fourth side surface 2f of the insulating substrate 2 and is provided with the first side surface conductive portion 3b. The side surface conductive portion 3b ₁ of the above is provided on the fourth side surface 2f of the insulating substrate 2, the second surface electrode 4 is extended to the third side surface 2e of the insulating substrate 2, and the second side surface conductive portion 4b is provided. The second side surface conductive portion 4b ₁ is provided on the third side surface 2e of the insulating substrate 2, the first side surface conductive portion 3b and the second side surface conductive portion 4b are located at opposite positions, and the first side surface conductive portion 3b ₁ and The second side surface conductive portion 4b ₁ is arranged at a diagonal position of the insulating substrate 2.

Although illustration is omitted, in the fuse element 30, the first back surface electrode 3a extends to the fourth side surface 2f of the insulation substrate 2 on the back surface 2b side of the insulation substrate 2 and the first side surface conductive portion is formed. 3b ₁ and the second back surface electrode 4a extends to the third side surface 2e of the insulating substrate 2 and is connected to the second side surface conductive portion 4b ₁ .

Since the fuse element 30 has the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ in addition to the first side surface conductive portion 3b and the second side surface conductive portion 4b, there are a plurality of current paths. It is possible to reduce the electric resistance value of the entire current path. Therefore, the fuse element 30 can handle a large current by reducing the electric resistance value of the current path.

[Modification 3]
Further, a modified example of the fuse element 1 described above will be described. Further, the portions substantially similar to those of the fuse element 1 described above are denoted by the same reference numerals, the description thereof will be omitted, and the differences will be described. Further, the equivalent circuit is the same as that described with reference to FIG.

As shown in FIG. 9, the fuse element 40 according to the modified example 3 has two conducting paths of a first side surface conductive portion 3b ₂ and a first side surface conductive portion 3b ₃ on the first side surface 2c of the insulating substrate 2. The second side surface conductive portion 4b ₂ and the second side surface conductive portion 4b ₃ are provided with two current paths on the second side surface 2d of the insulating substrate 2, and the first side surface conductive portion 3b ₂ and the second side surface are provided. The conductive portion 4b ₂ is arranged at the facing position, and the first side surface conductive portion 3b ₃ and the second side surface conductive portion 4b ₃ are arranged at the facing position.

Although not shown, in the fuse element 40, the first back surface electrode 3a is connected to the first side surface conductive portion 3b ₂ and the first side surface conductive portion 3b ₃ on the back surface 2b side of the insulating substrate 2. The second back surface electrode 4a is connected to the second side surface conductive portion 4b ₂ and the second side surface conductive portion 4b ₃ .

In the fuse element 40, a first side conductive portion 3b and the second side conductive portion 4b, a first side conductive portion 3b _2, respectively, a first side conductive portion 3b ₃ and second side conductive portion 4b _2, Since the second side surface conductive portion 4b _{3 has} a plurality of configurations, there are a plurality of current paths, and it is possible to reduce the electric resistance value of the entire current path. Therefore, the fuse element 40 can handle a large current by reducing the electric resistance value of the current path.

In the fuse element 40, the first side surface conductive portion 3b ₂ , the first side surface conductive portion 3b _3, the second side surface conductive portion 4b ₂ , and the second side surface conductive portion 4b ₃ are respectively connected to the first side surface of the insulating substrate 2. Side surface 2c and second side surface 2d, that is, the same side surface. Since the cut portion when cutting the insulating substrate from the mother substrate is the place where the through hole is lightened, it is possible to easily perform the cutting work in the portion where the plurality of through holes are arranged.

[Modification 4]
Further, a modified example of the fuse element 1 described above will be described. Further, the parts substantially similar to those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof will be omitted, and the differences will be described. Further, the equivalent circuit is the same as that described with reference to FIG.

As shown in FIG. 10, in the fuse element 50 according to Modification 4, the first surface electrode 3 is extended to the third side surface 2e of the insulating substrate 2, the first side surface conductive portion 3b is not provided, and the first side surface conductive portion 3b is provided. The side surface conductive portion 3b ₄ of the above is provided on the third side surface 2e of the insulating substrate 2, the second surface electrode 4 is extended to the third side surface 2e of the insulating substrate 2, and the second side surface conductive portion 4b is not provided. The second side surface conductive portion 4b ₄ is provided on the third side surface 2e of the insulating substrate 2, and the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ are insulated, including the third side surface conductive portion 10b. The substrate 2 is arranged on the third side face 2e, that is, on the same side face.

Although illustration is omitted, in the fuse element 50, the first back surface electrode 3a is extended to the third side surface 2e of the insulation substrate 2 on the back surface 2b side of the insulation substrate 2, and the first side surface conductive portion is formed. 3b ₄ and the second back surface electrode 4a extends to the third side surface 2e of the insulating substrate 2 and is connected to the second side surface conductive portion 4b ₄ .

In the fuse element 50, since the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ including the third side surface conductive portion 10b are arranged on the same side surface of the insulating substrate 2, the fuse element 50 is insulated from the mother substrate. Since the cutting place when cutting the substrate is the place where the through hole is cut out, it is possible to easily perform the cutting work

Further, in the fuse element 50, since the first side surface conductive portion 3b ₁ and the second side surface conductive portion 4b ₁ including the third side surface conductive portion 10b are arranged on the same side surface of the insulating substrate 2, the circuit During mounting on the board, the solder for connection is sucked up by the third side surface conductive portion 10b, the first side surface conductive portion 3b ₄ and the second side surface conductive portion 4b ₄ to ensure proper electrical connection. Since the work of visually confirming is completed only by looking at one side, the connection confirmation process can be simplified.

[Second Embodiment]
Next, the fuse element 60 according to the second embodiment will be described with reference to FIGS. 11 to 15. Further, the portions substantially similar to those of the fuse element 1 described above are denoted by the same reference numerals, the description thereof will be omitted, and the differences will be described. Further, the equivalent circuit is the same as that described with reference to FIG.

In this protection circuit, when a large current exceeding the rating of the fuse element 60 flows, the fuse element 7 is blown by self-heating (Joule heat) to interrupt the current path. Further, in this protection circuit, the heating element 5 is energized at a predetermined timing by a current control element provided on a circuit board or the like on which the fuse element 1 is mounted, and the fuse element 7 is melted by the heat generated by the heating element 5. The current path can be interrupted. 11 is a plan view showing the fuse element 60 with the case omitted, FIG. 12 is a plan view of the fuse element 60 seen from the back surface side, and FIG. 13 is a plan view of the fuse element 60. FIG.

[Fuse element]
As shown in FIGS. 11 to 13, the fuse element 60 includes an insulating substrate 2, a first surface electrode 3 and a second surface electrode 4 provided on the surface 2a of the insulating substrate 2 so as to face each other. , The heating element 5, the heating element lead-out electrode 6 electrically connected to the heating element 5, the first surface electrode 3, the second surface electrode 4 and the heating element lead-out electrode 6, and are connected to each other. A fuse element 7 that melts by heating and interrupts the current path between the first front surface electrode 3 and the second front surface electrode 4, and the first back surface electrode 3a and the second back surface electrode 3a provided on the back surface 2b of the insulating substrate 2. Which is formed as a hole penetrating the insulating substrate 2 and connects the first front surface electrode 3 and the second front surface electrode 4 to the first back surface electrode 3a and the second back surface electrode 4a, respectively. , A first penetrating conductive portion 15 and a second penetrating conductive portion 16 which are current paths between the front surface 2a and the back surface 2b of the insulating substrate 2, and the first front surface electrode 3 and the second front surface electrode. Reference numeral 4 has a first surface convex portion 3f and a second surface convex portion 4f, respectively, which project in regions contacting the first through conductive portion 15 and the second through conductive portion 16.

The fuse element 60 includes an insulator 9 that covers the heating element 5 and prevents contact between the heating element 5 and the heating element lead-out electrode 6, and a first element provided on the insulating substrate 2 at both ends of the heating element 5. The heating element electrode 10 and the second heating element electrode 11 are provided. One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11, and the other is connected to a midway portion of the fuse element 7.

Further, in the fuse element 60, as shown in FIG. 12, the first back surface electrode 3a and the second back surface electrode 4a are projected in a region in contact with the first penetrating conductive portion 15 and the second penetrating conductive portion 16. It has a first backside convex portion 3g and a second backside convex portion 4g.

The fuse element 60 is formed on the side surface of the insulating substrate 2 and connects the first front surface electrode 3 and the second front surface electrode 4 to the first back surface electrode 3a and the second back surface electrode 3b, respectively, and insulates them. Between the front surface 2a and the back surface 2b of the substrate 2, there are a first side surface conductive portion 3b and a second side surface conductive portion 4b which serve as a current path.

Specifically, the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the third side surface conductive portion 10b in the fuse element 60 are respectively the first side surface 2c, the second side surface 2d, and the second side surface 2d of the insulating substrate 2. It is provided on the third side surface 2e.

Here, the first surface convex portion 3f and the second surface convex portion 4f are the same as the first surface electrode 3 and the second surface electrode 4 in the rectangular shape described in the fuse element 1 described in the first embodiment. This shows a structure in which a part of the shape, which is close to the heating element 5 other than the regions corresponding to the first through conductive portion 15 and the second through conductive portion 16, is cut out. In other words, it can be said that it is a region protruding from the main part of the first surface electrode 3 in order to connect the first surface electrode 3 and the first penetrating conductive portion 15.

The fuse element 60 has a current path that penetrates the insulating substrate 2 in addition to the first side surface 2c and the second side surface 2d of the insulating substrate 2. It becomes easy to deal with.

The fuse element 60 corresponds to the first penetrating conductive portion 15 and the second penetrating conductive portion 16 on the side of the first surface electrode 3 and the second surface electrode 4 that is close to the heating element 5. Since the first surface protrusions 3f and the second surface protrusions 4f are formed only in the regions, the heat generated from the heating element 5 must diffuse to the first surface electrode 3 and the second surface electrode 4. The fuse element 7 can be concentrated and overheated.

Further, the fuse element 60 has the same structure as the first front surface electrode 3 and the second front surface electrode 4 on the side of the first back surface electrode 3a and the second back surface electrode 4a that is close to the heating element 5. Since the first back surface convex portion 3g and the second front surface convex portion 4g are formed only in the regions corresponding to the first penetrating conductive portion 15 and the second penetrating conductive portion 16, the heat generated from the heating element 5 is generated. The fuse element 7 can be concentrated and overheated without being diffused into the first back surface electrode 3a and the second back surface electrode 4a.

In the fuse element 60 according to the second embodiment, since the heating element 5 is arranged on the surface 2a of the insulating substrate 2, the heat diffusion prevention by the first surface convex portion 3f and the second surface convex portion 4f is prevented. The effect is particularly large.

Therefore, in the fuse element in which the heating element 5 is provided on the surface 2a of the insulating substrate 2, at least the first surface electrode 3 and the second surface electrode 4 have the first surface protrusion 3f and the second surface protrusion 3f. It is only necessary to have the front surface convex portion 4f, and it is not necessary to provide the first back surface convex portion 3g and the second back surface convex portion 4g.

Further, in the fuse element in which the heating element 5 is provided on the back surface 2b of the insulating substrate 2, the effect of preventing heat diffusion by the first back surface convex portion 3g and the second back surface convex portion 4g is particularly large.

Therefore, in the fuse element in which the heating element 5 is provided on the back surface 2b of the insulating substrate 2, at least the first back surface electrode 3a and the second back surface electrode 4a have the first back surface convex portion 3g and the second back surface electrode 3a. It is only necessary to have the back surface convex portion 4g, and it is not necessary to provide the first front surface convex portion 3f and the second front surface convex portion 4f.

Here, the first penetrating conductive portion 15 and the second penetrating conductive portion 16 are through holes, and in particular, by forming a filled through hole in which the inside of the hole is filled with a conductive material, the electric resistance value of the entire current path is increased. It is possible to enhance the effect of reducing

Here, when the effect of reducing the electric resistance value by the first through conductive portion 15 and the second through conductive portion 16 is high, the first side surface conductive portion 3b and the second side surface conductive portion 4b are not provided. The fuse element may be configured, but it is preferable to leave it as a half through hole for sucking up the adhesive solder in order to ensure the mounting state on the circuit board or the like.

In addition, the fuse element 60 is provided with two first through conductive portions 15 and two second through conductive portions 16. Therefore, the fuse element 60 includes the first front surface convex portion 3f, the second front surface convex portion 4f, the first back surface convex portion 3g, and the first rear surface protruding portion 3f corresponding to the first penetrating conductive portion 15 and the second penetrating conductive portion 16. Two rear surface convex portions 4g are also provided.

Note that the number of the first penetrating conductive portions 15 and the second penetrating conductive portions 16 provided, and the shape and diameter of the through holes can be appropriately changed in adjusting the electric resistance value of the current path, and the present embodiment. It is not limited to the description of.

[Summary]
As described above, the fuse element described as the first embodiment, each modified example, and the second embodiment prevents heat diffusion from the heating element to other than the fuse element, and the resistance value of the entire conductive path is reduced. It is possible to reduce the size, and it is possible to achieve downsizing of the element while supporting a large current.

The structure of the fuse element in the first embodiment may be a structure in which the above-described modifications are appropriately combined, and for example, the shape, the number, the arrangement position, etc. of the side surface conductive portions may be set in any combination. It goes without saying that it is good.

1, 20, 30, 40, 50, 60 Fuse element, 2 Insulating substrate, 2a Front surface, 2b Back surface, 2c First side surface, 2d Second side surface, 2e Third side surface, 2f Fourth side surface, 3rd 1st surface electrode, 3a 1st back surface electrode, 3b, 3c, 3d, 3e 1st side surface conductive part, 3f 1st surface convex part, 3g 1st back surface convex part, 4 2nd surface electrode, 4a 2nd back surface electrode, 4b, 4c, 4d, 4e 2nd side surface conductive part, 4f 2nd surface convex part, 4g 2nd back surface convex part, 5 heating element, 6 heating element extraction electrode, 7 fuse element, 7a Melt, 9 Insulator, 10 First heating element electrode, 10a Third back surface electrode, 10b Third side surface conductive portion, 11 Second heating element electrode, 15 First penetrating conductive portion, 16 Second Through conductive part

Claims (9)

An insulating substrate,
A first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other;
A heating element,
A heating element extraction electrode electrically connected to the heating element,
A current path connected between the first surface electrode, the second surface electrode, and the heating element lead-out electrode, melted by heating the heating element, and between the first surface electrode and the second surface electrode A fuse element for breaking the
A first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate;
Formed on the side surface of the insulating substrate, the first front surface electrode and the second front surface electrode are connected to the first back surface electrode and the second back surface electrode, respectively, and the front surface and the back surface of the insulation substrate are connected. Between the first front surface electrode and the second front surface electrode, and the first side surface conductive portion and the first side surface conductive portion that form all current paths connecting the first back surface electrode and the second back surface electrode. 2 side conductive parts ,
The insulating substrate is provided with a concave portion on a side surface corresponding to the first surface electrode and the second surface electrode, and the first side surface conductive portion and the second side surface conductive portion are formed in the concave portion,
The first side surface conductive portion and the second side surface conductive portion are respectively provided on side surfaces of the insulating substrate that face each other,
The first side surface conductive portion and the second side surface conductive portion are protection elements provided at positions offset from positions facing each other . An insulating substrate,
A first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other;
A heating element,
A heating element extraction electrode electrically connected to the heating element,
A current path connected between the first surface electrode, the second surface electrode, and the heating element lead-out electrode, melted by heating the heating element, and between the first surface electrode and the second surface electrode A fuse element for breaking the
A first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate;
Formed on the side surface of the insulating substrate, the first front surface electrode and the second front surface electrode are connected to the first back surface electrode and the second back surface electrode, respectively, and the front surface and the back surface of the insulation substrate are connected. Between the first front surface electrode and the second front surface electrode, and the first side surface conductive portion and the first side surface conductive portion that form all current paths connecting the first back surface electrode and the second back surface electrode. 2 side conductive parts ,
The insulating substrate is provided with a concave portion on a side surface corresponding to the first surface electrode and the second surface electrode, and the first side surface conductive portion and the second side surface conductive portion are formed in the concave portion,
The first side conductive part and the second side conductive part are protection elements provided on the same side of the insulating substrate . An insulating substrate,
A first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other;
A heating element,
A heating element extraction electrode electrically connected to the heating element,
A current path connected between the first surface electrode, the second surface electrode, and the heating element lead-out electrode, melted by heating the heating element, and between the first surface electrode and the second surface electrode A fuse element for breaking the
A first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate;
Formed on the side surface of the insulating substrate, the first front surface electrode and the second front surface electrode are connected to the first back surface electrode and the second back surface electrode, respectively, and the front surface and the back surface of the insulation substrate are connected. Between the first front surface electrode and the second front surface electrode, and the first side surface conductive portion and the first side surface conductive portion that form all current paths connecting the first back surface electrode and the second back surface electrode. 2 side conductive parts ,
The insulating substrate is provided with a concave portion on a side surface corresponding to the first surface electrode and the second surface electrode, and the first side surface conductive portion and the second side surface conductive portion are formed in the concave portion,
The said 1st side surface electroconductive part or the said 2nd side surface electroconductive part is a protection element provided in multiple numbers, respectively . The protection element according to any one of claims 1 to 3 , wherein the recess is a half through hole. The protection element according to any one of claims 1 to 4 , wherein the recess has a side surface of the insulating substrate formed of a non-planar surface including a curved surface. An insulating substrate,
A first surface electrode and a second surface electrode provided on the surface of the insulating substrate so as to face each other;
A heating element,
A heating element extraction electrode electrically connected to the heating element,
The first surface electrode, the second surface electrode, and the heating element lead-out electrode are connected and melted by heating the heating element, and a current path between the first surface electrode and the second surface electrode is formed. A fuse element to cut off,
A first back surface electrode and a second back surface electrode provided on the back surface of the insulating substrate;
The surface of the insulating substrate is formed as a hole penetrating the insulating substrate and connects the first front surface electrode and the second front surface electrode to the first back surface electrode and the second back surface electrode, respectively. A first penetrating conductive portion and a second penetrating conductive portion that serve as a current path between the back surface and the back surface,
The first surface electrode and the second surface electrode respectively have a first surface convex portion and a second surface convex portion that project in regions contacting the first through conductive portion and the second through conductive portion, respectively. A protective element having. The first back surface electrode and the second back surface electrode respectively have a first back surface convex portion and a second back surface convex portion that project in regions contacting the first through conductive portion and the second through conductive portion, respectively. The protection element according to claim 6 which has. The protection element according to claim 6 or 7 , wherein the first through conductive portion and the second through conductive portion are through holes. The protection element according to claim 6 or 7 , wherein the first penetrating conductive portion and the second penetrating conductive portion are hole-filling through holes in which holes are filled with a conductive material.

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