TW201633840A - Heating substrate, protection device, and electronic device - Google Patents

Abstract

A heating substrate includes a heat generator provided on a surface of an insulating substrate, and a power feeding terminal that feeds a current to the heat generator. The insulating substrate includes an originating hole and a terminating hole. The originating hole is located nearer to the power feeding terminal than the heat generator, and the terminating hole is located nearer to the generator than the power feeding terminal.

Description

Heating substrates, protective components and electronic equipment

The present invention relates to a heating substrate including a heating element, a protective element that melts the soluble conductor using the heating substrate, and an electronic device using the protective element.

In electronic equipment, it is important not only to ensure electrical performance, but also to ensure safety in the event of an abnormality such as overvoltage. Here, the electronic device is equipped with a protection element that can block the circuit when an abnormality occurs.

The protective element includes two external terminals that are connected to each other through a soluble conductor and a heating substrate that melts the soluble conductor. In the electronic device in which the protective element is mounted, the soluble conductor and the two external terminals form part of the circuit. The heating substrate is provided with a heating element on one surface of the insulating substrate.

When an abnormality such as an overvoltage is detected in the electronic device, the heat generating body generates heat in the protective element (heating substrate), and thus the heat generating body soluble conductor is heated. Thereby, since the soluble conductor is melted, the circuit is blocked. Therefore, it is possible to prevent excessive heat generation (thermal runaway) of the electronic device.

Various proposals have been made regarding the structure of the heating substrate used as a heating source in the protective element.

Specifically, in order to realize a safe and highly reliable heating operation of the wafer for preventing thermal runaway, a hole (through hole) for deteriorating thermal shock resistance is provided on the heating substrate provided with the resistance heating element (for example, reference) Patent Document 1).

In the wafer for preventing thermal runaway, when an abnormality occurs in the wafer, when the substrate is heated by the through hole as a starting point, the heat generating body or the like is broken due to the crack. Thereby, the thermal runaway of the heater is stopped.

[Previous Technical Literature]

[Patent Document] Japanese Patent Laid-Open No. Hei 11-097159

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-097159

In an electronic device, when it is detected that an abnormality has occurred, it is necessary to perform a heating operation using a heating substrate, but there is still room for improvement in reliability of the heating operation.

Therefore, it is desirable to provide a heating substrate, a protective element, and an electronic device that can ensure the reliability of the heating operation.

A first heating substrate according to an embodiment of the present invention includes a heating element and a power supply terminal on one surface of the insulating substrate on which the first hole and the second hole are provided, and supplies a current to the heating element. The first hole is located closer to the power supply terminal than the heat generating body, and the second hole is located closer to the heat generating body than the power supply terminal.

In the second heating substrate according to the embodiment of the present invention, a heating element is provided on one surface of the insulating substrate on which the first hole and the second hole are provided. The first hole is a point at which the insulating substrate is broken by the power supply to the heating element, and the second hole is a stopping point of the crack occurring in the first hole.

A first protection element according to an embodiment of the present invention includes two external terminals that are connected to each other via a soluble conductor, and a substrate that is heated to melt the soluble conductor. The heating substrate has the first embodiment of the present invention. The same structure of the substrate is heated.

A second protective element according to an embodiment of the present invention includes two external terminals that are connected to each other via a soluble conductor, and a substrate that is heated to melt the soluble conductor. The heating substrate has the second embodiment of the present invention. The same structure of the substrate is heated.

A first electronic device according to an embodiment of the present invention includes a protection element that blocks a circuit when an abnormality occurs, and the protection element has the same structure as the first protection element according to the above-described embodiment of the present invention.

A second electronic device according to an embodiment of the present invention includes a protection element that blocks a circuit when an abnormality occurs, and the protection element has the same structure as the second protection element according to the above-described embodiment of the present invention.

Here, the “first hole” may be a hole (through hole) penetrating the insulating substrate, or may be a hole (non-through hole) that does not penetrate the insulating substrate. The non-through hole is a recess in the thick direction of the insulating substrate. Further, the "second hole" may be the through hole or the non-through hole.

Further, the "first hole" may be a hole (complete hole) provided inside the outer edge of the insulating substrate, or may be a hole (incomplete hole) provided on the outer edge of the insulating substrate. The incomplete hole-shaped slit-shaped hole is a concave portion in a direction crossing the thick direction of the insulating substrate. Further, the "second hole" may be the complete hole or the incomplete hole.

According to the heating substrate, the protective element, or the electronic device according to the embodiment of the present invention, the first hole which is a point at which the occurrence of the crack occurs on one surface of the insulating substrate is provided closer to the power supply terminal side, and the second hole which is the stop point of the crack is provided on Closer to the side of the heating element. Therefore, it can be confirmed Guarantee the reliability of the heating action.

1‧‧‧Insert substrate

1E‧‧‧ outer edge

2‧‧‧heating body

3‧‧‧Power supply terminal

4‧‧‧ hole

5‧‧‧stop hole

6‧‧‧ wiring

7‧‧‧ slot

102,103‧‧‧External terminals

104‧‧‧Solid conductor

105‧‧‧heated substrate

Fig. 1A is a perspective view showing a structure of a heating substrate according to an embodiment of the present invention.

Fig. 1B is a plan view showing the configuration (side surface) of the heating substrate shown in Fig. 1A.

Fig. 1C is a plan view showing the configuration (upper surface) of the heating substrate shown in Fig. 1A.

Fig. 2 is a plan view for explaining the disadvantages of the heating substrate of the first comparative example.

Fig. 3 is a plan view for explaining advantages of a heating substrate according to an embodiment of the present invention.

4 is a plan view showing a structure (1) of a heating substrate according to Modification 1.

Fig. 5 is a plan view showing a structure (2) of the heating substrate of the first modification.

Fig. 6 is a plan view showing a structure (3) of a heating substrate according to a first modification.

Fig. 7 is a plan view showing a structure (4) of a heating substrate according to a first modification.

Fig. 8 is a plan view for explaining the disadvantages of the heating substrate of the second comparative example.

Fig. 9 is a plan view for explaining the disadvantages of the heating substrate of the third comparative example.

Fig. 10 is a plan view showing a structure (side surface) of a heating substrate according to a second modification.

Fig. 11 is a plan view showing a structure (upper surface) of a heating substrate according to a second modification.

Figure 12 is a cross-sectional view showing the configuration of a protective member according to an embodiment of the present invention.

Figure 13 is a cross-sectional view showing another configuration of the protective member shown in Figure 12 .

Fig. 14 is a block diagram showing the circuit configuration of an application example (electronic device) relating to the protective element of the present invention.

An embodiment of the present invention will be described in detail below with reference to the drawings. In addition, the order of explanation is as follows.

1. Heating the substrate

1-1. Construction

1-2. Action

1-3. Function and effect

1-5. Modification 2

2. Protection components

2-1. Construction

2-2. Action

2-3. Function and effect

3. Application examples of protection components (electronic devices)

<1. Heating the substrate>

First, a heating substrate according to an embodiment of the present invention will be described.

<1-1. Construction>

Fig. 1A shows a three-dimensional structure of a heating substrate. Fig. 1B shows the planar configuration of the side surface (XZ plane) of the heating substrate shown in Fig. 1A. Fig. 1C shows the planar configuration of the upper surface (XY plane) of the heating substrate shown in Fig. 1A.

In addition, in FIGS. 1A to 1C, the upper side (arrow direction) in the Z-axis direction shown in FIG. 1B is referred to as "upper", and the lower side (direction opposite to the direction of the arrow) in the Z-axis direction is referred to as Make "down."

The heating substrate described here uses a heating element to self-heat and utilizes the A substrate that heats a heated object by self-heating. The type of the object to be heated is not particularly limited as long as it is required to be heated for some reason depending on the heating. Moreover, the use of the heating substrate is not particularly limited as long as it requires heating for some reason.

[The overall structure of the heating substrate]

As shown in FIGS. 1A to 1C, the heating substrate includes a heating element 2 and a power supply terminal 3 on one surface (upper surface) of the insulating substrate 1 on which two holes (the generating hole 4 and the stopping hole 5) are provided. The heating element 2 is separated from the power supply terminal 3, for example, and is connected to the power supply terminal 3 via the wiring line 6.

The number of the heating elements 2 and the number of the wirings 6 are not particularly limited. In other words, the number of the heating elements 2 may be one or two or more. Similarly, the number of the wires 6 may be one or two or more.

The connection form of the heating element 2 and the wiring 6 is not specifically limited. In other words, the number of the wires 6 connected to one heating element 2 may be one or two or more.

Here, for example, one heating element 2 is connected to one wiring 6. In this case, when one heating element 2 and one wiring 6 are set as one set, the number of the groups may be one set or two or more sets.

Here, for example, the number of groups of the heating element 2 and the wiring 6 is two sets. Accordingly, the heating substrate includes, for example, two heat generating bodies 2 (2A, 2B) and two wirings 6 (6A, 6B). That is, the power supply terminal 3 is connected to the heating element 2A through the wiring 6A, and is connected to the heating element 2B through the transmission wiring 6B.

[Insulating substrate]

The insulating substrate 1 includes, for example, one or two or more kinds of insulating materials such as an inorganic insulating material and an organic insulating material. The inorganic insulating material is, for example, a metal oxide, a ceramic, or the like. Metal oxidation The substance is, for example, alumina, zirconia, mullite or the like. Ceramics are, for example, glass ceramics and alumina ceramics. The organic insulating material is, for example, a glass epoxy resin, phenol or the like. In particular, the insulating substrate 1 including an organic insulating material may be a printed wiring board such as a glass epoxy substrate or a phenol substrate.

The structure of the insulating substrate 1 other than this is not particularly limited. Specifically, the planar shape of the insulating substrate 1 is, for example, a rectangle (square and rectangle), a circle (including an ellipse), and a polygon (excluding a rectangle). Here, the planar shape of the insulating substrate 1 is, for example, a rectangle. Although the thickness of the insulating substrate 1 is not particularly limited, it is, for example, about 0.5 mm to about 0.65 mm.

[heating stuff]

The heating element 2 is a heat source (heater) that self-heats in response to power supply (energization), and the heating substrate uses the heating element 2 to function as a heating source. Further, in FIGS. 1A to 1C, a shallow mesh bottom is attached to the heat generating body 2.

The heating element 2 includes, for example, one or two or more types of high-resistance conductive materials that can self-heat according to power supply. The conductive material is, for example, a metal material such as tungsten (W), molybdenum (Mo), or ruthenium (Ru). However, the conductive material may be a monomer of a metal material, a compound of a metal material, or an alloy of two or more metal materials. The type of the compound is not particularly limited, and examples thereof include an oxide of the above metal material. The metal material may be a monomer, a compound, or an alloy, and the same applies hereinafter.

The structure of the heating element 2 other than this is not specifically limited. Specifically, the details of the planar shape of the heating element 2 are, for example, the same as the details of the planar shape of the insulating substrate 1 described above. Here, for example, the planar shape of the heating element 2 is a rectangle. The thickness of the heating element 2 is not particularly limited and is, for example, about 50 μm.

[Power supply terminal]

The power supply terminal 3 is a power supply terminal for supplying a current to the heat generator 2 and energizing the heat generator 2 . Further, in FIGS. 1A to 1C, a deep mesh bottom is attached to the power supply terminal 3.

The power supply terminal 3 includes, for example, one or two or more types of conductive materials. The conductive material is, for example, a metal material such as gold (Au), silver (Ag), copper (Cu), iron (Fe), nickel (Ni), palladium (Pd), lead (Pb), and tin (Sn).

As will be described later, in the case where the generation hole 4 is provided at a position overlapping the power supply terminal 3, the formation range of the power supply terminal 3 is not particularly limited. In this case, the power supply terminal 3 may cover only the upper surface of the insulating substrate 1 in the vicinity of the generation hole 4.

Among them, the power supply terminal 3 preferably covers not only the upper surface of the insulating substrate 1, but also the inner wall surface of the insulating substrate 1 in which the inside of the hole 4 is formed. Since the formation area of the power supply terminal 3 becomes large, it is easy to supply power to the heat generating body 2 using the power supply terminal 3.

Further, although the power supply terminal 3 may cover only a part of the inner wall surface of the insulating substrate 1, it is preferable to cover all of the inner wall surfaces. This is because the formation area of the power supply terminal 3 will become larger.

The configuration of the power supply terminal 3 other than this is not particularly limited. Specifically, the details of the planar shape of the power supply terminal 3 are, for example, the same as the details of the planar shape of the insulating substrate 1 described above. Here, for example, the planar shape of the power supply terminal 3 is circular. The thickness of the power supply terminal 3 is not particularly limited and is, for example, about 50 μm.

[occurring hole]

The generation hole 4 is a hole (first hole) that is a point of occurrence (starting point) of the fracture when the insulating substrate 1 is broken by the power supply to the heating element 2. That is, in the case where the insulating substrate 1 is broken, the occurrence position of the crack is controlled so that the crack occurs as the starting point of the occurrence of the hole 4. In addition, The number of occurrence holes 4 may be one or two or more.

As described above, the generation hole 4 may be a hole (through hole) penetrating the insulating substrate 1 or a hole (non-through hole) that does not penetrate the insulating substrate 1. This non-through hole is a recess in the thick direction (Y-axis direction) of the insulating substrate 1. However, since the occurrence hole 4 is provided on one surface of the insulating substrate 1, the generation hole 4 which is a non-through hole is opened on the upper surface side of the insulating substrate 1.

Further, the generation hole 4 may be a hole (complete hole) provided inside the outer edge 1E of the insulating substrate 1, or may be a hole (incomplete hole) provided at the outer edge 1E of the insulating substrate 1. The incomplete hole-shaped slit-shaped hole is a concave portion in a direction (Y-axis direction) that intersects the thick direction of the insulating substrate 1.

Here, for example, the number of the occurrence holes 4 is one. Further, for example, the hole 4 is formed as a through hole and is an incomplete hole. That is, the generation hole 4 is provided on the outer edge 1E of the insulating substrate 1 so as to penetrate the insulating substrate 1.

The generation hole 4 is different from the stop hole 5 in that it is located closer to the power supply terminal 3 than the heating element 2. This is because the insulating substrate 1 is locally heated in the vicinity of the power supply terminal 3 which is the starting point of the current supply when the heating element 2 is supplied with power. Therefore, in the case where the insulating substrate 1 is broken due to the internal stress generated at the time of heating, the insulating substrate 1 is easily broken by the occurrence of the hole 4 as a starting point. Further, the above internal stress is considered to occur mainly due to a temperature difference occurring in the insulating substrate 1.

Although the generation hole 4 may be a through hole or a non-through hole as described above, it is preferably a through hole. This is because the insulating substrate 1 is easily broken by the occurrence of the hole 4 in the case where the insulating substrate 1 is broken in the internal stress caused by the heating.

Moreover, although the generation hole 4 may be a complete hole as described above, it may be incomplete. Holes, but among them are preferably incomplete holes. This is because the insulating substrate 1 is easily broken by the occurrence of the hole 4 in the case where the insulating substrate 1 is broken in the internal stress caused by the heating.

Here, in the case where the insulating substrate 1 is broken, in order to cause the occurrence of cracks in the occurrence hole 4, the specific position of the generation hole 4 is not particularly limited as long as it is in the vicinity of the power supply terminal 3.

Among them, the generation hole 4 is preferably provided at a position overlapping the power supply terminal 3. In other words, it is preferable that the formation position of the generation hole 4 coincides with the formation position of the power supply terminal 3, whereby the generation hole 4 is provided in the range in which the power supply terminal 3 is formed. Thus, the distance between the hole 4 and the power supply terminal 3 becomes the shortest. Therefore, when the heating element 2 is supplied with power (when the insulating substrate 1 is heated), when the insulating substrate 1 is broken by the internal stress generated in the vicinity of the power supply terminal 3, the insulating substrate 1 is easily broken by the occurrence of the hole 4 as a starting point.

Of course, although the position at which the hole 4 is formed does not necessarily coincide with the position at which the power supply terminal 3 is formed, the distance between the hole 4 and the power supply terminal 3 is preferably as small as possible. This is because the insulating substrate 1 is susceptible to the above internal stress in the vicinity of the occurrence of the hole 4.

The details of the planar shape (opening shape) of the generating hole 4 are, for example, the same as the details of the planar shape of the insulating substrate 1 described above. However, the planar shape of the occurrence hole 4 of the incomplete hole is a part of the shape of the above-described rectangle or the like. Here, for example, the planar shape of the hole 4 is a part of a shape (a semicircular shape) in a circle.

Further, in order to form the generation hole 4, for example, after the insulating substrate 1 in which the generation hole 4 is not provided is prepared, the insulating substrate 1 may be subjected to a perforation process using a laser or the like. In addition to this, for example, the insulating substrate 1 may be molded using a mold. The method of forming the generation hole 4 is the same as the method of forming the stop hole 5, for example.

[stop hole]

The stop hole 5 is a hole (second hole) that is a stop point of the break when the insulating substrate 1 is broken from the occurrence of the hole 4 . That is, in the case where the insulating substrate 1 is broken, the progress of the crack is controlled so that the crack stops at the end of the stop hole 5. Further, the number of the stop holes 5 may be one or two or more.

Similarly to the above-described generation hole 4, the stop hole 5 may be a through hole or a non-through hole. Among them, a through hole is preferred. In the case where the insulating substrate 1 is broken due to internal stress occurring during heating, the cracking is likely to stop with the stop hole 5 as an end point.

Further, the stop hole 5 may be a complete hole or an incomplete hole similarly to the above-described generation hole 4. Among them, a complete pore is preferred. Since the insulating substrate 1 is broken in the internal stress caused by the heating, the crack easily stops at the end of the stop hole 5.

Specifically, the stop hole 5 is provided to prevent the crack from reaching the heating element 2 when the insulating substrate 1 is broken from the occurrence of the hole 4 . In this case, for example, the stop hole 5 is preferably provided at a position close to the heat generating body 2 so as not to be close to the generating hole 4, that is, to be disposed inside the outer edge 1E of the insulating substrate 1. Therefore, the stop hole 5 is preferably provided on the inner side of the outer edge 1E of the insulating substrate 1, that is, a complete hole.

Here, for example, the number of the stop holes 5 is one. Further, for example, the stop hole 5 is a through hole and is a complete hole. In other words, the stop hole 5 is provided inside the outer edge 1E of the insulating substrate 1 so as to penetrate the insulating substrate 1.

The stop hole 5 is located closer to the heat generating body 2 than the power supply terminal 3, unlike the generating hole 4. When the power supply to the heating element 2 is supplied and the insulating substrate 1 is broken, the rupture tends to expand toward the heating element 2 . In order to suppress the heating element 2 caused by the rupture The wire is broken, and the stop hole 5 needs to be disposed in the vicinity of the heat generating body 2.

The details of the planar shape (opening shape) of the stop hole 5 are the same as the details of the planar shape of the insulating substrate 1 described above and the details of the planar shape of the generating hole 4, for example. Here, for example, the planar shape of the stop hole 5 is circular.

Here, in the case where the heating element 2 is supplied with power and the insulating substrate 1 is broken, the specific position of the stop hole 5 is not particularly limited as long as the rupture can be stopped.

In order to improve the possibility that the rupture stops at the stop hole 5, the positional relationship between the heating element 2, the power supply terminal 3, the generation hole 4, and the stop hole 5 preferably satisfies one or two of the following two conditions (position conditions). One.

Position Condition 1: The stop hole 5 is located on the center line L of the insulating substrate 1 with reference to the position at which the hole 4 is formed.

Positional condition 2: The distance Y between the occurrence hole 4 and the stop hole 5 is smaller than the distance X between the generation hole 4 and the heating element 2.

In the position condition 1, when the center line (center line) L is drawn on the upper surface of the insulating substrate 1 with the position of the hole 4 as a reference, the stop hole 5 is disposed so as to overlap the center line L. In this case, the center position of the stop hole 5 may be located on the center line L or may be offset from the center line L.

The reason why it is preferable to satisfy the positional condition 1 is that the crack tends to advance in the direction of the center line L when the insulating substrate 1 is broken from the occurrence of the hole 4 . In view of this tendency, by arranging the stop hole 5 so as to overlap the center line L, it is possible to increase the possibility that the breakage stops at the stop hole 5.

In the position condition 2, since the distance Y is relatively small, the stop hole 5 is configured. Since the position near the generation hole 4 which is the occurrence point of the fracture is relatively large because the distance X is relatively large, the heat generation body 2 is disposed at a position away from the generation hole 4. Further, the distance X is the shortest distance between the hole 4 and the heat generating body 2, and the distance Y is the shortest distance between the hole 4 and the stop hole 5.

It is preferable to satisfy the positional condition 2 because the stop hole 5 is disposed closer to the position where the hole 4 is formed than the heat generating body 2. Therefore, when the insulating substrate 1 is broken as a starting point of the occurrence of the hole 4, the rupture is likely to stop at the stop hole 5 before reaching the heating element 2, so that it is difficult to reach the heating element 2.

It suffices that any one of the positional conditions 1 and 2 is satisfied, but it is preferable to satisfy two of them. This is because the advantages described above with respect to positional condition 1 and the advantages of positional condition 2 can be obtained at the same time.

[wiring]

The wiring 6 includes, for example, the same material as the material for forming the power supply terminal 3.

When the heating element 2 and the power supply terminal 3 are connected to each other through the wiring 6, as described above, when the insulating substrate 1 is broken from the occurrence of the hole 4, the crack stops at the stop hole 5. Thereby, since the rupture does not easily reach the wiring 6, it is possible to suppress the disconnection of the wiring 6 caused by the rupture.

The configuration of the wiring 6 other than this is not particularly limited. Specifically, the planar shape of the wiring 6 may be linear or curved, or may include two or more of these shapes. The pattern shape of the wiring 6 may be bent once or more in the middle, for example.

<1-2. Action>

This heating substrate operates, for example, as follows.

When a heating substrate is used, if current is supplied to the power supply terminal 3, because of the electricity Since the flow is supplied to the heat generating body 2 by the wiring 6, the heat generating body 2 is supplied with power (energized). Thereby, since the heating element 2 generates heat, the object to be heated is heated by the heating substrate.

<1-3. Action and effect>

According to the above-described heating substrate, on one surface of the insulating substrate 1, a generation hole 4 is provided on the side close to the power supply terminal 3, and a stop hole 5 is provided on the side close to the heating element 2. The generation hole 4 is a hole that becomes a point at which the fracture occurs when the insulating substrate 1 is broken based on the power supply to the heating element 2. The stop hole 5 is a hole that becomes a stop point of the break when the insulating substrate 1 is broken. Therefore, the reliability of the heating operation can be ensured for the following reasons.

Fig. 2 is a plan view corresponding to Fig. 1C for explaining the disadvantages of the heating substrate of the first comparative example. Fig. 3 is a plan view corresponding to Fig. 1C for explaining the advantages of the heating substrate of the present embodiment.

The heating substrate of the first comparative example has the same structure as the heating substrate of the present embodiment except that the stop hole 5 is not provided. In the heating substrate of the first comparative example, as shown in FIG. 2, when the heating element 2 is supplied with power, when the insulating substrate 1 is partially heated due to local heating in the vicinity of the power supply terminal 3, the hole 4 is used as a starting point. Cracks C1 and C2 occur.

The ruptures C1 and C2 mainly extend along the median line L, and continue to expand while deviating from the median line L. In this case, the crack C1 which is deviated from the center line L at an earlier stage is likely to be expanded so as to cross the wiring 6A, so that the possibility that the wiring 6A is broken is high. In addition, although the crack C2 which is deviated from the center line L at a relatively late stage does not cross the wiring 6A, since it is easy to expand so that the heat generating body 2A is cross-cut, the possibility of disconnection of the heat generating body 2A becomes high. In either case, since the heating element 2A cannot be normally heated due to the cracks C1 and C2, the reliability of the heating operation is lowered.

Further, in the case where the entire heat generating body 2A is cut across the crack C2, the heat generating body 2A is cut off in the middle. In this case, since one portion of the heat generating body 2A becomes unenergized, a part of the heat generating body 2A becomes unable to generate heat.

The problem of the above-described crack C2 and the heat generating body 2A is also generated in the crack C1 and the wiring 6A.

On the other hand, in the heating substrate of the present embodiment, as shown in FIG. 3, when the heating element 2 is supplied with power and the insulating substrate 1 is broken, the crack C3 is generated from the occurrence of the hole 4 as a starting point.

The rupture C3, like the above-described ruptures C1 and C2, mainly spreads along the median line L. However, since the stop hole 5 is provided in the progress direction of the crack C3, the crack C3 cannot be expanded to the area beyond the stop hole 5, and the stop hole 5 is stopped. In this case, since the crack C3 does not easily spread to the heat generating body 2, the possibility that the heat generating body 2 is broken is low. Similarly, the crack C3 does not easily spread to the wiring 6, so the possibility that the wiring 6 is broken is low. Thereby, even if the crack C3 occurs, since the heat generating body 2A can generate heat normally, the reliability with respect to the heating operation becomes high. Therefore, the reliability with respect to the heating operation can be ensured.

In particular, when the hole 4 is a through hole, when the insulating substrate 1 is broken, it is easy to cause the hole 4 to be broken as a starting point, so that a higher effect can be obtained. Further, when the stop hole 5 is a through hole, when the insulating substrate 1 is broken, the breakage is likely to stop at the stop hole 5, so that a higher effect can be obtained.

In addition, when the occurrence of the hole 4 is a slit-shaped incomplete hole provided in the outer edge 1E of the insulating substrate 1, when the insulating substrate 1 is broken, it is easy to cause cracking from the generation hole 4, so that it is possible to obtain higher Effect. Moreover, if the stop hole 5 is a complete hole provided on the inner side of the outer edge 1E of the insulating substrate 1, in the case where the insulating substrate 1 is broken, it is easy to break. Since the stop hole 5 is stopped, a higher effect can be obtained.

Further, when the occurrence hole 4 is provided at a position overlapping the power supply terminal 3, when the insulating substrate 1 is broken, it is easy to cause the occurrence of the crack from the generation hole 4, so that a higher effect can be obtained.

When the positional relationship between the heating element 2, the power supply terminal 3, the generation hole 4, and the stop hole 5 satisfies one or two of the above-described positional conditions 1 and 2, when the insulating substrate 1 is broken, the hole is formed. The crack that occurs at 4 as the starting point is likely to stop at the stop hole 5, so that a higher effect can be obtained.

Further, when the heating element 2 and the power supply terminal 3 are connected to each other through the wiring 6, as described above, not only the disconnection of the heating element 2 but also the disconnection of the wiring 6 is suppressed, so that a higher effect can be obtained.

<1-4. Modification 1>

Further, the heating element 2, the power supply terminal 3, the generating hole 4, and the stopping hole 5 may be arbitrarily changed in terms of the number of components and the position.

The structure of the heating substrate can also be changed as shown in FIGS. 4 to 7 corresponding to FIG. 1C. The structure of the heating substrate shown in Figs. 4 to 7 is the same as that of the heating substrate shown in Fig. 1C except for the points explained below. Even in the case shown in FIGS. 4 to 7, it is easy to stop the stop hole 5 because the crack generated from the occurrence of the hole 4 is stopped, so that the reliability with respect to the heating operation can be ensured.

[its 1]

In FIG. 4, for example, the stop hole 5 is disposed at a position away from the power supply terminal 3. In this case, although the position condition 1 in the above-described positional conditions 1, 2 is satisfied, the positional condition 2 is not satisfied. also That is, although the stop hole 5 is located on the center line L, the distance Y is larger than the distance X.

[its 2]

In FIG. 5, for example, the stop hole 5 is held at a distance Y, and is disposed at a position deviated from the center line L. In this case, although the position condition 1 in the above positional conditions 1, 2 is not satisfied, the positional condition 2 is satisfied. That is, the stop hole 5 is not located on the center line L, but the distance Y is smaller than the distance X.

[its 3]

In FIG. 6, for example, the number of power supply terminals 3 is changed from one to two, and the number of occurrences of the holes 4 is changed from one to two. That is, the heating substrate includes two power supply terminals 3 (3A, 3B) and two generation holes 4 (4A, 4B). The positions of the occurrence holes 4A and 4B are not particularly limited as long as they are not disposed so as to overlap each other. The power supply terminal 3A is connected to the heating element 2A via the wiring 6A, for example, and the power supply terminal 3B is connected to the heating element 2B via the wiring 6B, for example. In this case, any one of the above positional conditions 1 and 2 is satisfied.

[its 4]

In FIG. 7, for example, the number of the heating elements 2 is changed from two to one, and the wirings 6C and 6D are used instead of the wirings 6A and 6B. The heating element 2 is disposed, for example, such that its center is located on the center line L. The stop hole 5 is disposed between the generation hole 4 and the heating element 2. The power supply terminal 3 is connected to the heating element 2 through, for example, two wirings 6C and 6D. In this case, any one of the above positional conditions 1 and 2 is satisfied.

Fig. 8 is a plan view corresponding to Fig. 7 for explaining the disadvantages of the heating substrate of the second comparative example. Fig. 9 is a plan view corresponding to Fig. 7 for explaining the disadvantages of the heating substrate of the third comparative example.

The heating substrate of the second comparative example has the same structure as the heating substrate shown in FIG. 7 except that the stop hole 5 is not provided. The heating substrate of the third comparative example has the same structure as the heating substrate shown in FIG. 7 except that the power supply terminal 3 is connected to the heating element 2 through one wiring 6.

The problem of the heating substrate of the first comparative example described with reference to FIG. 2 was similarly produced in the heating substrate of the second comparative example and the heating substrate of the third comparative example. Specifically, in the heating substrate of the second comparative example, as shown in FIG. 8, when the cracks C4 and C5 are generated from the occurrence of the hole 4, the wiring 6C is broken due to the crack C4, and the crack is caused by the crack. C5 and the heating element 2 is broken. Further, in the heating substrate of the third comparative example, as shown in FIG. 9, when the cracks C6 and C7 are generated from the occurrence of the hole 4, the wiring 6 is broken due to the crack C6, and the crack C7 is caused by the crack. The heating element 2 is broken.

On the other hand, in the heating substrate shown in FIG. 7, as described with reference to FIG. 3, even if the crack C3 occurs from the occurrence of the hole 4, since the crack C3 stops at the stop hole 5, the breakage of the heat generating body 2 and The disconnection of the wirings 6C, 6D is suppressed.

<1-5. Modification 2>

Further, as shown in FIG. 10 corresponding to FIG. 1B and FIG. 11 corresponding to FIG. 1C, a groove 7 connecting the generation hole 4 and the stop hole 5 may be provided between the generation hole 4 and the stop hole 5. Since the groove 7 is a so-called recess, it does not penetrate the insulating substrate 1.

In this case, if the crack occurs as the starting point of the generating hole 4, since the crack propagates along the groove 7, it is easy to induce to the stop hole 5. Thereby, since the rupture is less likely to reach the heating element 2 and the wiring 6, the reliability with respect to the heating operation can be improved.

The groove 7 may be linear or curved, or may be composed of two types. These shapes are on. Further, the groove 7 may have one or more bends in the middle. Among them, the groove 7 is preferably linear along the median line L. Since the distance of the groove 7, that is, the induced distance of the rupture becomes the shortest, it is easier to induce the rupture to the stop hole 5.

Further, conditions such as the amplitude, depth, and sectional shape of the groove 7 can be arbitrarily set. Here, as shown in FIG. 10, the cross-sectional shape of the groove 7 is a rectangle.

<2. Protection element>

Next, a protective element to which a heating substrate according to an embodiment of the present invention is applied will be described.

The protective element described here is a so-called fuse. When the abnormality such as an overcurrent or an overvoltage occurs, the protective element is mounted on an electronic device in order to block the circuit. The type of the electronic device is not particularly limited.

In particular, the protective element to which the above-described heating substrate is applied includes a function of blocking a circuit in response to an overcurrent (a circuit interruption function in a current interruption mode), and a heating substrate (heat generating body 2) when an abnormality such as an overvoltage occurs. The function of the interrupting circuit (the circuit blocking function of the heating interrupt mode).

<2-1. Construction>

12 and 13 show the cross-sectional structure of the protective element. Hereinafter, constituent elements of the heating substrate of one embodiment of the present invention which have been described will be referred to at any time.

As shown in FIGS. 12 and 13, the protective element includes three external terminals 102, 103, and 106, a soluble conductor 104, and a heating substrate 105 inside the casing 101. The soluble conductor 104 extends from the external terminal 102 toward the direction of the external terminal 103 (X-axis direction).

The housing 101 is an exterior of the protective component, for example, including any of engineering plastics and the like. One or two or more. The engineering plastics are, for example, polyphenylene sulfide (PPS) and liquid crystal polymer (LCP).

The shape of the casing 101 is not particularly limited. For example, the shape of the XY plane may be a cylinder such as a circle or an ellipse, or a cube having a rectangular cross section and a rectangular parallelepiped may be used.

The external terminals 102, 103 are connected to each other through the soluble conductor 104. In an electronic device equipped with a protective element, the external terminals 102, 103 and the soluble conductor 104 form part of a circuit. The external terminal 102 is led out to the outside through the casing 101, for example, at one end side in the extending direction of the soluble conductor 104, and the external terminal 103 is led to the outside through the casing 101, for example, at the other end side in the extending direction of the soluble conductor 104.

Each of the external terminals 102 and 103 includes, for example, one or two or more kinds of conductive materials similar to those of the power supply terminal 3, and specifically includes copper or the like. Further, the external terminals 102, 103 may contain the same kind of materials, and may also contain different kinds of materials.

The configuration of the soluble conductor 104 is not particularly limited. Here, for example, the soluble conductor 104 includes three portions (the central portion 104A, the one end portion 104B, and the other end portion 104C). The one end portion 104B is disposed between the external terminal 102 and the central portion 104A, for example, and the central portion 104A is connected to the external terminal 102 through the one end portion 104B. The other end portion 104C is disposed, for example, between the external terminal 103 and the center portion 104A, and the center portion 104A is connected to the external terminal 103 through the other end portion 104C.

The soluble conductors 104 are self-heating in response to an overcurrent, and include one or two or more types of conductive materials (conductive melting materials) that can be melted by the self-heating. The conductive molten material is, for example, a SnAgCu-based lead-free solder or the like. Further, the conductive molten material is, for example, a BiPbSn alloy, a BiPb alloy, a BiSn alloy, a SnPb alloy, a PbIn alloy, ZnAl alloy, InSn alloy, PbAgSn alloy, and the like.

The heating substrate 105 has the same structure as the heating substrate of one embodiment of the present invention described above. However, in FIGS. 12 and 13, the heating substrate 105 is schematically illustrated. The heating substrate 105 is disposed such that the heating element 2 is adjacent to the central portion 104A of the soluble conductor 104.

The external terminal 106 is connected to the power supply terminal 3 in the heating substrate 105. The external terminal 106 is guided to the outside through the casing 101 at one end side in the direction (Y-axis direction) intersecting the extending direction of the soluble conductor 104, for example. Further, the external terminal 106 includes, for example, any one or two or more of the same conductive materials as the external terminals 102 and 103.

<2-2. Action>

[Current Interrupt Mode]

The protection element performs a protection operation of the current interruption mode, for example, as described below.

In the protective element mounted on the electronic device, as described above, the external terminals 102 and 103 are connected to each other through the soluble conductor 104. In this case, the external terminals 102, 103 and the soluble conductor 104 form part of the circuit, and the external terminals 102, 103 are in a state of being electrically conductive.

When an electronic device is used, if an overcurrent (current exceeding a design value) flows through the circuit, the soluble conductor 104 self-heats (resistance heat) in response to the overcurrent. Therefore, when the soluble conductor 104 generates heat until it reaches a temperature equal to or higher than the melting point, the soluble conductors 104 are melted, so that the external terminals 102 and 103 are not electrically connected. Therefore, the circuit is blocked.

[heating interrupt mode]

Further, the protection element performs a protection operation of the heating interruption mode, for example, as described below.

For example, when the protective element is mounted on an electronic device such as a battery pack, When an abnormality such as an overvoltage (overcharge) is detected in the electronic device, power is supplied to the heating element 2 through the external terminal 106 in the heating substrate 105. The details of the operation of the electronic device will be described later (see FIG. 14). When the heating element 2 self-heats in response to the power supply, the self-heating soluble conductor 104 is heated by the self-heating. Therefore, when the soluble conductor 104 is heated until it reaches a temperature equal to or higher than the melting point, the soluble conductor 104 is melted, so that the external terminals 102 and 103 are not electrically connected. Therefore, the circuit is blocked.

As described above, although the protection operation of the heating interruption mode is performed when an abnormality is detected, the abnormality is not limited to the above-described overvoltage, and includes other causes such as temperature rise and impact.

<2-3. Action and effect>

According to the above protective element, the heating substrate 105 has the same structure as the heating substrate of one embodiment of the present invention described above. In this case, as described above, even when the insulating substrate 1 is broken when the heating substrate 105 is used, since the heating element 2 can normally generate heat, the reliability with respect to the heating operation becomes high. Further, since the heating element 2 can be normally heated, the soluble substrate 104 can be sufficiently heated by the heating substrate 105 when an abnormality occurs, so that the reliability of the protection operation is also high. Therefore, the operational reliability of the protection element can be ensured.

The action and effect of the protective element other than this are the same as those of the heating substrate according to an embodiment of the present invention. Of course, the modified examples 1 and 2 described with reference to FIGS. 4 to 7 , 10 , and 11 may be applied to the heating substrate 105 .

<3. Application example of protection element (electronic equipment)>

Next, an electronic device according to an application example of the protective element according to an embodiment of the present invention will be described. In addition, in the following description, the composition of the protective element already described is quoted at any time. Prime.

The type of electronic device to which the protective element of one embodiment of the present invention is applied is not particularly limited. Hereinafter, a battery pack will be described as an example of an electronic apparatus to which a protective element of one embodiment of the present invention is applied. However, the type of the electronic device is not limited to the battery module, and other electronic devices that are necessary to interrupt the circuit as needed may be used.

Fig. 14 shows the circuit configuration of a battery pack 200 to which a protective element is applied.

Further, in FIG. 14, together with the battery pack 200, a charging device 40 for charging the battery pack 200 is also shown. The battery pack 200 is detachable from the charging device 40, and FIG. 14 shows a state in which the battery pack 200 is connected to the charging device 40.

The battery pack 200 includes, for example, a protection element 100, one or two or more secondary batteries 20, a detection circuit 25, a current control element 28, and a charge and discharge control circuit 30. That is, the protection element 100 is incorporated into the circuit of the battery assembly 200.

The protection element 100 is disposed between the secondary battery 20 and the charge and discharge control circuit 30. In the protection element 100, the external terminal 102 is connected to the secondary battery 20, the external terminal 103 is connected to the positive terminal 26, and the external terminal 106 is connected to the current control element 28. Thereby, since the protective element 100 is disposed on the path through which the charging current flows when the secondary battery 20 is being charged and is disposed on the path through which the discharging current flows when the secondary battery 20 is discharged, the soluble conductor 104 is disposed in the second time. The battery 20 is charged and discharged on the path.

This protective element 100 has the same configuration as the protective element of one embodiment of the present invention described above. That is, the protection element 100 has a circuit interruption function of the current interruption mode and a circuit interruption function of the heating interruption mode. In the protection element 100, the heating interrupt mode is implemented. In the case of a protection action, the protection action of the protection element 100 is controlled by the current control element 28.

The type of the secondary battery 20 is not particularly limited, and is, for example, any one or two or more of lithium ion secondary batteries. Here, for example, the secondary battery 20 includes four secondary batteries 21 to 24 connected in series to form a so-called battery pack.

The secondary battery 20 is connected to the charging device 45 through the positive electrode terminal 26 and the negative electrode terminal 27. Thereby, since the charging voltage can be applied from the charging device 40 to the secondary battery 20, the secondary battery 20 can be charged.

The detection circuit 25 is connected to the secondary battery 20 and the charge and discharge control circuit 30, respectively. The detection circuit 25 outputs the measurement result to the charge and discharge control circuit 30 after measuring the voltage of the secondary battery 20. Here, for example, since the secondary battery 20 includes four secondary batteries 21 to 24, the detection circuit 25 measures the voltages of the secondary batteries 21 to 24, respectively.

Further, the detection circuit 25 is connected to the current control element 28. The detection circuit 25 outputs an interruption signal to the current control element 28 as necessary based on the voltage measurement result of the secondary battery 20. The blocking signal is a signal for performing a protection operation of the heating interruption mode in the protection element 100.

The current control element 28 is a switching element for controlling the action of the protection element 100, such as a field effect transistor (FET). The current control element 28 is coupled to the detection circuit 25 and to the external terminal 106 of the protection element 100.

The charge and discharge control circuit 30 includes two current control elements 31 and 32 and a control unit 33 that controls charging and discharging of the secondary battery 20 .

Each of the current control elements 31, 32 is, for example, a field effect transistor (FET) or the like. Current paths of the current control elements 31, 32 disposed between the secondary battery 20 and the charging device 40 Up, and in series.

The control unit 33 operates by supplying power from the charging device 45, and controls the operations of the current control elements 31, 32.

After the secondary battery 20 is charged, the battery pack 200 is detached from the charging device 40, and then connected to other electronic devices (hereinafter referred to as "operation target devices") to be operated through the positive electrode terminal 26 and the negative electrode terminal 27. The type of the operation target device is not particularly limited, and is, for example, a notebook personal computer or the like. Thereby, since the electric power is supplied from the battery pack 200 to the operation target device, the operation target device can be operated.

The battery pack 200 operates, for example, in the manner described below.

The control unit 33 determines whether or not the secondary battery 20 is abnormal (overcharged state or overdischarged state) based on the detection result of the detection circuit 25 (voltage of the secondary battery 20). When determining that the secondary battery 20 is abnormal, the control unit 33 blocks the supply of current to the secondary battery 20 by controlling the gate voltages of the current control elements 31 and 32.

Further, if an overcurrent exceeding the rated current flows through the secondary battery 20, as described above, the protection operation of the current interruption mode is performed in the protection element 100. That is, in the protective element 100, since the soluble conductor 104 is melted, the current path between the secondary battery 20 and the charging device 40 is blocked.

Moreover, the detection circuit 25 determines whether or not an abnormality (overvoltage state or the like) has occurred in the secondary battery 20 based on the detection result (voltage of the secondary battery 20). When the detection circuit 25 determines (detects) that the secondary battery 20 is abnormal, it outputs an interruption signal to the current control element 28.

When the blocking signal is output from the detecting circuit 28, as described above, the protection operation of the heating interrupt mode is performed in the protective element 100. That is, the current control element 28 can be directed to the protection element 100 supply current. In this case, when the secondary battery 20 is supplied with electric current to the heating element 2 via the external terminal 106, the heating element 2 generates heat, and the soluble conductor 104 is heated by the heating element 2. Thereby, since the soluble conductor 104 is melted, the current path between the secondary battery 20 and the charging device 40 is blocked regardless of the operation of the current control elements 31 and 32.

According to the above battery assembly 200, the protective member 100 has the same configuration as the protective member of one embodiment of the present invention. In this case, as described above, since the reliability of the heating operation is high, the reliability of the protection operation is also high. Therefore, it is possible to ensure the reliability of the protection action. The other functions and effects are the same as those of the embodiment of the present invention.

[Examples]

The embodiments of the present invention will be described in detail.

(Examples 1, 2)

The protective elements shown in Figs. 12 and 13 were produced in the following procedure.

After the alumina ceramic substrate is prepared, the alumina ceramic substrate is subjected to a perforation treatment using a laser to form the generation hole 4 and the stop hole 5. Thus, the insulating substrate 1 is obtained.

In this case, the planar shape of the occurrence of the hole 4 is made circular, and the generation hole 4 is formed as a through hole and an incomplete hole. The planar shape of the stop hole 5 is formed into a circular shape, and the stop hole 5 is formed as a through hole and a complete hole. The stop hole 5 is disposed on the center line L based on the generation hole 4. The following structure was prepared: the inner diameter of the occurrence hole 4 = 0.5 mm, the inner diameter of the stop hole 5 = 0.65 mm, the distance X = 2 mm, and the distance Y - 1.8 mm.

Next, on the insulating substrate 1, a pattern of each of the heating element 2 (tantalum oxide), the power supply terminal 3 (silver), and the wiring 6 (silver) is formed. In this case, it will contain various kinds of yttrium oxide and the like. After the paste thick film of the material is printed on the surface of the insulating substrate 1, the thick film is fired.

Thereby, the heating substrate 105 shown in FIGS. 1A to 1C is completed. Further, for comparison, the heating substrate 105 shown in Fig. 2 was formed by the same procedure except that the stop hole 5 was not formed.

Next, the external terminals 102 and 103 are connected to each other through the soluble conductor 104, and after the external terminal 106 is connected to the heating substrate 105 (the power supply terminal 3), the heating substrate 105 is disposed such that the heating element 2 is adjacent to the soluble conductor 104. . Finally, the external terminals 102, 103, and 106, the soluble conductor 104, and the heating substrate 105 are housed inside the casing 101. Thereby, the protection element is completed. The structure of the main portion of the protective element (the presence or absence of the occurrence of the hole 4 and the presence or absence of the stop hole 5) are shown in Table 1.

The behavior characteristics (heating interruption mode) of the protective element were investigated, and the results as shown in Table 1 were obtained. When the operation characteristics are investigated, electric power (maximum 120 W) is supplied between the external terminals 102 and 103 and the external terminal 106 in a state where the external terminals 102 and 103 outside the casing 101 are short-circuited, so that the substrate is heated. 105 (heating element 2) is hot. As a result, whether or not the soluble conductor 104 was melted was visually observed, and the insulation resistance (Ω) was measured using a tester.

The protective element corresponds to the presence or absence of the stop hole 5, showing a completely different behavior.

Specifically, in the case where the stop hole 5 is not formed (Experimental Example 2), When the crack occurs as the starting point 4, the crack reaches the heating element 2. In this case, since the heating element 2 cannot normally self-heat, the soluble conductor 104 is not sufficiently heated by the heating element 2. Thus, since the soluble conductor 104 is not sufficiently melted, the insulation resistance is not increased.

On the other hand, in the case where the stop hole 5 is formed (Experimental Example 1), if the crack occurs as the starting point of the generating hole 4, the crack stops in the stop hole 5, and therefore the heating element 2 is not reached. In this case, since the heating element 2 can normally self-heat, the soluble conductor 104 is sufficiently heated by the heating element 2. Thereby, since the soluble conductor 104 is sufficiently melted, the insulation resistance is remarkably increased.

As is apparent from the results shown in Table 1, when the generation hole 4 and the stop hole 5 are provided in the insulating substrate 1, the circuit is blocked during the protection operation of the heating interruption mode. Therefore, the reliability of the heating operation of the heating substrate 105 can be ensured, and the protection operation of the protective element on which the heating substrate 105 is mounted can be ensured.

The present invention has been described above by way of embodiments and examples, but the present invention is not limited to the embodiments described in the embodiments and the examples, and various changes can be made. For example, the structure of the heating substrate and the structure of the protective element are not limited to those described in the above embodiment, and may be appropriately changed.

The present application claims priority on the basis of Japanese Patent Application No. 2014-246694, filed on Dec.

The various modifications, combinations, sub-combinations and alterations of the inventions are intended to be included within the scope of the appended claims.

1‧‧‧Insert substrate

1E‧‧‧ outer edge

2 (2A, 2B) ‧ ‧ heating element

3‧‧‧Power supply terminal

4‧‧‧ hole

5‧‧‧stop hole

6 (6A, 6B) ‧‧‧ wiring

Claims (18)

A heating substrate comprising: a heating element on one surface of an insulating substrate provided with a first hole and a second hole; and a power supply terminal for supplying a current to the heating element, wherein the first hole is located closer to the power supply terminal than the heating element The second hole is located closer to the heat generating body than the power supply terminal. The heating substrate according to claim 1, wherein at least one of the first hole and the second hole is a through hole. The heating substrate according to the first or second aspect of the invention, wherein the first hole is provided in a slit-shaped incomplete hole at an outer edge of the insulating substrate, and the second hole is provided outside the insulating substrate. A complete hole that lies on the inside. The heating substrate according to any one of the items 1 to 3, wherein the first hole is provided at a position overlapping the power supply terminal. The heating substrate according to any one of the items 1 to 4, wherein, in the heating element, the positional relationship between the first hole and the second hole of the power supply terminal satisfies at least the following two conditions: One condition 1: the second hole is located on the center line of the insulating substrate based on the position of the first hole, and Condition 2: the distance between the first hole and the second hole is larger than the first hole The distance between the above heating elements is small. The heating substrate according to any one of the items 1 to 5, wherein the one surface of the insulating substrate includes a wiring that connects the heating element and the power supply terminal. The heating substrate according to any one of claims 1 to 6, wherein a groove for connecting the first hole and the second hole is provided on one surface of the insulating substrate. A heating substrate including a heating element on one surface of an insulating substrate on which the first hole and the second hole are provided, wherein the first hole is a point at which the insulating substrate is broken due to power supply to the heating element, and the second hole It is the stopping point of the crack that occurs in the above first hole. A protective element comprising: two external terminals connected to each other via a soluble conductor; and a substrate that is heated to melt the soluble conductor, wherein the heating substrate includes one surface of the insulating substrate on which the first hole and the second hole are provided: And a power supply terminal that supplies a current to the heat generating body, wherein the first hole is located closer to the power supply terminal than the heat generating body, and the second hole is located closer to the heat generating body than the power supply terminal. The protective element according to claim 9, wherein at least one of the first hole and the second hole is a through hole. The protective element according to claim 9 or 10, wherein the first hole is provided in a slit-shaped incomplete hole at an outer edge of the insulating substrate, and the second hole is provided outside the insulating substrate A complete hole that lies on the inside. The protective element according to any one of the items 9 to 11, wherein the first hole is provided at a position overlapping the power supply terminal. The protective element according to any one of the preceding claims, wherein the position of the first hole and the second hole of the heat generating body and the power supply terminal satisfies at least the following two conditions: One condition 1: the second hole is located on the center line of the insulating substrate based on the position of the first hole, and Condition 2: the distance between the first hole and the second hole is larger than the first hole The distance between the above heating elements is small. The protective element according to any one of the items 9 to 13, wherein the one surface of the insulating substrate is provided with a wiring that connects the heating element and the power supply terminal. The protective element according to any one of claims 9 to 14, wherein a groove for connecting the first hole and the second hole is provided on one surface of the insulating substrate. A protective element comprising: two external terminals connected to each other via a soluble conductor; and a substrate heated to melt the soluble conductor, wherein the heating substrate has heat generated on one surface of the insulating substrate on which the first hole and the second hole are provided The first hole is a point at which the insulating substrate is broken due to power supply to the heat generating body, and the second hole is a stop point of cracking occurring in the first hole. An electronic device including a protection element that blocks a circuit when an abnormality occurs, wherein the protection element includes two external terminals that are connected to each other through a soluble conductor, and a substrate that is heated to melt the soluble conductor. The heating substrate includes a heat generating body on one surface of the insulating substrate on which the first hole and the second hole are provided, and a power supply terminal that supplies current to the heat generating body, and the first hole is located closer to the power supply terminal than the heat generating body. Further, the second hole is located closer to the heat generating body than the power supply terminal. An electronic device including a protection element that blocks a circuit when an abnormality occurs, wherein the protection element includes two external terminals that are connected to each other through a soluble conductor, and a substrate that is heated to melt the soluble conductor, and the heating substrate is One surface of the insulating substrate on which the first hole and the second hole are provided includes a heat generating body, and the first hole is a point at which the insulating substrate is broken by power supply to the heat generating body, and the second hole is in the first hole The stopping point of the rupture that occurred.