JP6877607B2 - Heating substrates, protective elements and electronic devices - Google Patents

Description

The present invention relates to a heating substrate provided with a heating element, a protective element for melting a soluble conductor using the heating substrate, and an electronic device using the protective element.

In electronic devices, it is important not only to ensure electrical performance, but also to ensure safety in the event of an abnormality such as overvoltage. Therefore, the electronic device is equipped with a protective element capable of interrupting the electric circuit when an abnormality occurs.

The protective element includes two external terminals connected to each other via a soluble conductor and a heating substrate for melting the soluble conductor. In an electronic device equipped with the protective element, the soluble conductor and 2 are provided. The two external terminals form part of the electrical circuit. The heating substrate includes a heating element on one surface of the insulating substrate.

In electronic devices, when the occurrence of an abnormality such as overvoltage is detected, the heating element generates heat in the protective element (heating substrate), so that the heating element heats the soluble conductor. As a result, the soluble conductor melts, and the electric circuit is interrupted. Therefore, excessive heat generation (thermal runaway) of the electronic device is prevented.

As described above, various proposals have already been made regarding the configuration of the heating substrate used as the heating source in the protective element.

Specifically, in order to realize a safe and highly reliable heating operation in the thermal runaway prevention chip, the heater substrate provided with the resistance heating element has holes (through holes) for deteriorating the thermal shock resistance. It is provided (see, for example, Patent Document 1).

In this thermal runaway prevention chip, when a crack occurs in the heater substrate starting from the through hole when an abnormality occurs, the heating element or the like is disconnected due to the crack. As a result, the thermal runaway of the heater is stopped.

Japanese Unexamined Patent Publication No. 11-097159

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

The present invention has been made in view of such problems, and an object of the present invention is to provide a heating substrate, a protective element, and an electronic device capable of ensuring reliability regarding a heating operation.

Heating the substrate of the present invention includes a heating element on one surface of the insulating substrate on which the first hole and the second hole are provided, the second hole cracking of the insulating substrate generated in the first hole to reach the heating element It is arranged in a position to suppress this, and further has a power supply terminal that supplies current to the heating element, the first hole is located closer to the power supply terminal than the heating element, and the second hole is from the power supply terminal. Is also located on the side closer to the heating element.

The protective element of the present invention includes two external terminals connected to each other via a soluble conductor and a heating substrate for melting the soluble conductor, and the heating substrate is the same as the heating substrate of the present invention described above. It has a structure.

The electronic device of the present invention includes a protective element that cuts off an electric circuit when an abnormality occurs, and the protective element has the same configuration as the above-mentioned protective element of the present invention.

Here, the "first hole" may be a hole that penetrates the insulating substrate (through hole) or a hole that does not penetrate the insulating substrate (non-through hole). This non-through hole is a recess in the thickness direction of the insulating substrate. The same applies to the "second hole" that the through hole or the non-through hole may be used.

Further, the "first hole" may be a hole (complete hole) provided inside the outer edge of the insulating substrate, or a hole (incomplete hole) provided on the outer edge of the insulating substrate. This incomplete hole is a notch-shaped (or notched-shaped) hole, and is a recess in a direction intersecting the thickness direction of the insulating substrate. The same applies to the "second hole" that the hole may be a complete hole or an incomplete hole.

According to the heating substrate, the protective element, or the electronic device of the present invention, the insulating substrate is provided with the first hole and the second hole, and the second hole generates heat due to the cracking of the insulating substrate generated in the first hole. It is arranged at a position that prevents it from reaching the body , the power supply terminal supplies current to the heating element, the first hole is located closer to the power supply terminal than the heating element, and the second hole is from the power supply terminal. Is also located on the side closer to the heating element . Therefore, the reliability of the heating operation can be ensured.

It is a perspective view which shows the structure of the heating substrate of one Embodiment of this invention. It is a top view which shows the structure (side surface) of the heating substrate shown in FIG. 1A. It is a top view which shows the structure (top surface) of the heating substrate shown in FIG. 1A. It is a top view for demonstrating the problem about the heating substrate of 1st comparative example. It is a top view for demonstrating the advantage about the heating substrate of one Embodiment of this invention. It is a top view which shows the structure (the 1) of the heating substrate of the modification 1. FIG. It is a top view which shows the structure (the 2) of the heating substrate of the modification 1. It is a top view which shows the structure (the 3) of the heating substrate of the modification 1. It is a top view which shows the structure (the 4) of the heating substrate of the modification 1. It is a top view for demonstrating the problem about the heating substrate of 2nd comparative example. It is a top view for demonstrating the problem about the heating substrate of 3rd comparative example. It is a top view which shows the structure (side surface) of the heating substrate of the modification 2. It is a top view which shows the structure (top surface) of the heating substrate of the modification 2. It is sectional drawing which shows the structure of the protection element of one Embodiment of this invention. It is another cross-sectional view which shows the structure of the protection element shown in FIG. It is a block diagram which shows the circuit structure of the application example (electronic device) concerning the protection element of this invention.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. The order of explanation is as follows.

1. 1. Heating substrate 1-1. Configuration 1-2. Operation 1-3. Actions and effects 1-4. Modification 1
1-5. Modification 2
2. Protective element 2-1. Configuration 2-2. Operation 2-3. Action and effect 3. Application example of protective element (electronic device)

<1. Heating substrate ＞
First, the heating substrate according to the embodiment of the present invention will be described.

<1-1. Configuration>
FIG. 1A shows the perspective configuration of the heating substrate. FIG. 1B shows the planar configuration of the side surface (XZ surface) of the heating substrate shown in FIG. 1A. FIG. 1C shows the planar configuration of the upper surface (XY surface) of the heating substrate shown in FIG. 1A.

In FIGS. 1A to 1C, the upper side (direction of the arrow) 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 "upper". Called "bottom".

The heating substrate described here is a substrate that self-heats using a heating element and heats an object to be heated by utilizing the self-heating. The type of the object to be heated is not particularly limited as long as it requires heating for some reason, such as an object that exerts its function in response to heating. Further, the use of the heating substrate is not particularly limited as long as it requires heating for some reason.

[Overall configuration of heating substrate]
In the heating substrate, for example, as shown in FIGS. 1A to 1C, a heating element 2 and a power supply are supplied to one surface (upper surface) of the insulating substrate 1 provided with two holes (generation hole 4 and stop hole 5). It has a terminal 3. 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 6.

The number of heating elements 2 and the number of wirings 6 are not particularly limited. That is, the number of heating elements 2 may be only one or two or more. Similarly, the number of wirings 6 may be only one or two or more.

The connection form between the heating element 2 and the wiring 6 is not particularly limited. That is, the number of wirings 6 connected to one heating element 2 may be only one or two or more.

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

Here, for example, the number of pairs of the heating element 2 and the wiring 6 is two. Along with this, the heating substrate includes, for example, two heating elements 2 (2A, 2B) and two wirings 6 (6A, 6B). That is, the power feeding terminal 3 is connected to the heating element 2A via the wiring 6A and is connected to the heating element 2B via the wiring 6B.

[Insulating substrate]
The insulating substrate 1 contains, for example, any one or more of insulating materials such as an inorganic insulating material and an organic insulating material. Inorganic insulating materials are, for example, metal oxides and ceramics. Metal oxides include, for example, aluminum oxide, zirconium oxide and mullite. Ceramics are, for example, glass ceramics and alumina ceramics. Organic insulating materials are, for example, glass epoxies and phenols. In particular, the insulating substrate 1 containing the organic insulating material may be a printed wiring board such as a glass epoxy substrate or a phenol substrate.

The configuration 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, for example, the planar shape of the insulating substrate 1 is rectangular. The thickness of the insulating substrate 1 is not particularly limited, but is, for example, about 0.5 mm to about 0.65 mm.

[Heating element]
The heating element 2 is a heat generating source (heater) that self-heats in response to power supply (energization), and the heating substrate functions as a heating source using the heating element 2. In FIGS. 1A to 1C, the heating element 2 is lightly shaded.

The heating element 2 contains, for example, any one or more of high resistance conductive materials capable of self-heating in response to power feeding. This conductive material is, for example, a metal material such as tungsten (W), molybdenum (Mo) and ruthenium (Ru). However, the conductive material may be a simple substance of a metal material, a compound of a metal material, or an alloy of two or more kinds of metal materials. The type of this compound is not particularly limited, and is, for example, the oxide of the above-mentioned metal material. The fact that the metal material may be a simple substance, a compound, or an alloy as described above will be the same thereafter.

The configuration of the heating element 2 other than this is not particularly limited. Specifically, the details regarding the planar shape of the heating element 2 are the same as the details regarding the planar shape of the insulating substrate 1 described above, for example. Here, for example, the planar shape of the heating element 2 is rectangular. The thickness of the heating element 2 is not particularly limited, but is, for example, about 50 μm.

[Power supply terminal]
The power supply terminal 3 is a terminal for power supply used to supply an electric current to the heating element 2 and energize the heating element 2. In FIGS. 1A to 1C, the power supply terminal 3 is darkly shaded.

The power feeding terminal 3 contains, for example, any one or more of the conductive materials. This conductive material is a metal such as gold (Au), silver (Ag), copper (Cu), iron (Fe), nickel (Ni), palladium (Pd), lead (Pb) and tin (Sn). It is a material.

As will be described later, when 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 feeding terminal 3 may cover only the upper surface of the insulating substrate 1 in the vicinity of the generation hole 4.

Above all, it is preferable that the power feeding terminal 3 covers not only the upper surface of the insulating substrate 1 but also the inner wall surface of the insulating substrate 1 inside the generation hole 4. This is because the forming area of the power feeding terminal 3 becomes large, so that it becomes easy to supply power to the heating element 2 by using the power feeding terminal 3.

Further, the power feeding terminal 3 may cover only a part of the inner wall surface of the insulating substrate 1, but it is preferable that the power feeding terminal 3 covers the entire inner wall surface thereof. This is because the forming area of the power feeding terminal 3 becomes larger.

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

[Generation hole]
The generation hole 4 is a hole (first hole) that becomes a generation point (starting point) of the crack when the insulating substrate 1 is cracked based on the power supply to the heating element 2. That is, when the insulating substrate 1 is cracked, the crack generation position is controlled so that the crack is generated starting from the generation hole 4. The number of generation holes 4 may be only one or two or more.

As described above, the generation hole 4 may be a hole (through hole) that penetrates 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 thickness direction (Y-axis direction) of the insulating substrate 1. However, since the generation hole 4 is provided on one surface of the insulating substrate 1, the generation hole 4, which is a non-through hole, opens 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 a hole (incomplete hole) provided in the outer edge 1E of the insulating substrate 1. This incomplete hole is a notch-shaped (or notched-shaped) hole, and is a recess in a direction (Y-axis direction) intersecting the thickness direction of the insulating substrate 1.

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

Unlike the stop hole 5, the generation hole 4 is located closer to the power supply terminal 3 than the heating element 2. This is because when power is supplied to the heating element 2, the insulating substrate 1 is locally heated in the vicinity of the power supply terminal 3, which is the current supply start point. As a result, when the insulating substrate 1 is cracked due to the internal stress generated during heating, the insulating substrate 1 is liable to crack starting from the generation hole 4. It is considered that the above-mentioned internal stress is mainly generated due to the temperature difference generated in the insulating substrate 1.

As described above, the generation hole 4 may be a through hole or a non-through hole, but among them, a through hole is preferable. This is because when the insulating substrate 1 is cracked due to the internal stress generated during heating, the insulating substrate 1 is easily cracked starting from the generation hole 4.

Further, as described above, the generation hole 4 may be a complete hole or an incomplete hole, but among them, the incomplete hole is preferable. This is because when the insulating substrate 1 is cracked due to the internal stress generated during heating, the insulating substrate 1 is easily cracked starting from the generation hole 4.

Here, the specific position of the generation hole 4 is not particularly limited as long as it is as close to the power feeding terminal 3 as possible in order to facilitate cracking in the generation hole 4 when the insulating substrate 1 is cracked. ..

Above all, it is preferable that the generation hole 4 is provided at a position overlapping the power feeding terminal 3. In other words, it is preferable to provide the generation hole 4 within the range in which the power supply terminal 3 is formed by matching the formation position of the generation hole 4 with the formation position of the power supply terminal 3. This is because the distance between the generation hole 4 and the power supply terminal 3 is the shortest. As a result, when the insulating substrate 1 is cracked by utilizing the internal stress generated in the vicinity of the feeding terminal 3 when the heating element 2 is fed (when the insulating substrate 1 is heated), the insulating substrate 1 is generated. It becomes easy to crack starting from the hole 4.

Of course, the formation position of the generation hole 4 and the formation position of the power supply terminal 3 do not necessarily have to coincide with each other, but it is preferable that the distance between the generation hole 4 and the power supply terminal 3 is as small as possible. This is because the insulating substrate 1 is easily affected by the above-mentioned internal stress in the vicinity of the generation hole 4.

The details regarding the planar shape (opening shape) of the generation hole 4 are the same as the details regarding the planar shape of the insulating substrate 1 described above, for example. However, the planar shape of the generation hole 4, which is an incomplete hole, is a part of the above-mentioned figure such as a rectangle. Here, for example, the planar shape of the generation hole 4 is a part of a circle (semi-circular).

In order to form the generation holes 4, for example, the insulating substrate 1 without the generation holes 4 may be prepared, and then the insulating substrate 1 may be perforated using a laser or the like. In addition, for example, the insulating substrate 1 may be molded using a mold. The method for forming the generation hole 4 is the same as for the method for forming the stop hole 5, for example.

[Stop hole]
The stop hole 5 is a hole (second hole) that becomes a stop point for the crack when the insulating substrate 1 is cracked starting from the generation hole 4. That is, when a crack occurs in the insulating substrate 1, the progress of the crack is controlled so that the crack stops at the stop hole 5 as an end point. The number of stop holes 5 may be only one or two or more.

The stop hole 5 may be a through hole or a non-through hole, similarly to the generation hole 4 described above. Above all, it is preferable that it is a through hole. This is because when the insulating substrate 1 is cracked due to the internal stress generated during heating, the crack is likely to stop at 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 generation hole 4 described above. Above all, it is preferable that the holes are perfect. This is because when the insulating substrate 1 is cracked due to the internal stress generated during heating, the crack is likely to stop at the stop hole 5 as an end point.

Specifically, the stop hole 5 is provided to prevent the crack from reaching the heating element 2 when the insulating substrate 1 is cracked starting from the generation hole 4. In this case, it is preferable that the stop hole 5 is provided, for example, at a position closer to the heating element 2 than the generation hole 4, that is, inside the outer edge 1E of the insulating substrate 1. Therefore, the stop hole 5 is preferably a hole provided inside the outer edge 1E of the insulating substrate 1, that is, a complete hole.

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

Unlike the generation hole 4, the stop hole 5 is located closer to the heating element 2 than the power supply terminal 3. This is because when the insulating substrate 1 is cracked when power is supplied to the heating element 2, the crack tends to spread closer to the heating element 2. In order to suppress disconnection of the heating element 2 due to this cracking, the stop hole 5 needs to be arranged in the vicinity of the heating element 2.

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

Here, the specific position of the stop hole 5 is not particularly limited as long as it is a position where the cracking can be stopped when the insulating substrate 1 is cracked when power is supplied to the heating element 2.

Above all, in order to increase the possibility that the cracking stops in 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 is one of the following two conditions (positional conditions). It is preferable that one or both are satisfied.

Positional condition 1: The stop hole 5 is located on the median line L of the insulating substrate 1 with reference to the position of the generation hole 4.
Positional condition 2: The distance Y between the generation 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 median line (center line) L is drawn on the upper surface of the insulating substrate 1 with reference to the position of the generation hole 4, the stop hole 5 is arranged so as to overlap the median line L. In this case, the center position of the stop hole 5 may be located above the median line L or may be off the median line L.

It is preferable to satisfy the position condition 1 because when the insulating substrate 1 is cracked starting from the generation hole 4, the crack tends to proceed in the direction along the median line L. Based on this tendency, by arranging the stop hole 5 so as to overlap the median plane L, the possibility that the crack stops at the stop hole 5 is high.

In the position condition 2, since the distance Y is relatively small, the stop hole 5 is arranged at a position close to the generation hole 4, which is the crack generation point, whereas the distance X is relatively large, so that heat is generated. The body 2 is arranged at a position far from the generation hole 4. The distance X is the shortest distance between the generation hole 4 and the heating element 2, and the distance Y is the shortest distance between the generation hole 4 and the stop hole 5.

It is preferable to satisfy the position condition 2 because the stop hole 5 is arranged at a position closer to the generation hole 4 than the heating element 2. As a result, when the insulating substrate 1 is cracked starting from the generation hole 4, the crack is likely to stop in the stop hole 5 before reaching the heating element 2, so that it is difficult to reach the heating element 2. ..

Only one of the position conditions 1 and 2 may be satisfied, but it is preferable that both of them are satisfied. This is because both the above-mentioned advantages regarding the position condition 1 and the advantages regarding the position condition 2 can be obtained.

[wiring]
The wiring 6 contains, for example, a material similar to the material for forming the power feeding terminal 3.

When the heating element 2 and the power supply terminal 3 are connected to each other via the wiring 6, as described above, when the insulating substrate 1 is cracked starting from the generation hole 4, the crack is the stop hole 5. Stop at. As a result, it becomes difficult for the crack to reach the wiring 6, and the disconnection of the wiring 6 due to the crack is also suppressed.

The configuration of the wiring 6 other than this is not particularly limited. Specifically, the planar shape of the wiring 6 may be a straight line, a curved line, or a shape including two or more of them. The pattern shape of the wiring 6 may be bent once or more in the middle, for example.

<1-2. Operation>
This heating substrate operates as follows, for example.

When a heating substrate is used, when a current is supplied to the power feeding terminal 3, the current is supplied to the heating element 2 via the wiring 6, so that the heating element 2 is fed (energized). As a result, the heating element 2 generates heat, so that the object to be heated is heated by the heating substrate.

<1-3. Actions and effects>
According to the heating substrate described above, on one surface of the insulating substrate 1, a generation hole 4 is provided on the side close to the power feeding 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 generation point of the crack when the insulating substrate 1 is cracked in response to the power supply to the heating element 2. The stop hole 5 is a hole that becomes a stop point of the crack when the insulating substrate 1 is cracked. Therefore, the reliability of the heating operation can be ensured for the following reasons.

FIG. 2 shows a planar configuration corresponding to FIG. 1C in order to explain a problem regarding the heating substrate of the first comparative example. FIG. 3 shows a planar configuration corresponding to FIG. 1C to illustrate the advantages of the heating substrate of this embodiment.

The heating substrate of the first comparative example has the same configuration as the heating substrate of the present embodiment except that the heating substrate 5 is not provided. In the heating substrate of the first comparative example, as shown in FIG. 2, when the insulating substrate 1 is cracked due to being locally heated in the vicinity of the feeding terminal 3 when the heating element 2 is fed. C1 and C2 are cracked from the generation hole 4 as a starting point.

The cracks C1 and C2 mainly spread along the median plane L, and then continue to spread while deviating from the median plane L. In this case, the crack C1 that deviates from the median plane L at a relatively early stage tends to spread so as to cross the wiring 6A, so that the wiring 6A is more likely to be broken. Further, although the crack C2 deviating from the median line L at a relatively late stage does not cross the wiring 6A, it easily spreads so as to cross the heating element 2A, so that the heating element 2A is more likely to be disconnected. In either case, the heating element 2A cannot normally generate heat due to the cracks C1 and C2, so that the reliability of the heating operation is lowered.

When the crack C2 crosses the entire heating element 2A, the heating element 2A is divided in the middle. In this case, since a part of the heating element 2A is not energized, a part of the heating element 2A cannot generate heat.

The above-mentioned problems concerning the crack C2 and the heating element 2A also occur 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 insulating substrate 1 is cracked when the heating element 2 is fed, crack C3 is generated starting from the generation hole 4.

The crack C3 spreads mainly along the median line L, similarly to the cracks C1 and C2 described above. However, since the stop hole 5 is provided in the traveling direction of the crack C3, the crack C3 cannot extend to a region beyond the stop hole 5 and stops at the stop hole 5. In this case, since the crack C3 is difficult to spread until it reaches the heating element 2, the possibility that the heating element 2 is broken is low. Similarly, since the crack C3 is difficult to spread until it reaches the wiring 6, the possibility that the wiring 6 is broken is low. As a result, even if the crack C3 is generated, the heating element 2A can normally generate heat, so that the reliability of the heating operation is improved. Therefore, the reliability of the heating operation can be ensured.

In particular, if the generating hole 4 is a through hole, when the insulating substrate 1 is cracked, cracking is likely to occur starting from the generating hole 4, so that a higher effect can be obtained. Further, if the stop hole 5 is a through hole, when the insulating substrate 1 is cracked, the crack is likely to stop in the stop hole 5, so that a higher effect can be obtained.

Further, if the generation hole 4 is a notch-shaped incomplete hole provided in the outer edge 1E of the insulating substrate 1, when the insulating substrate 1 is cracked, cracks are likely to occur starting from the generation hole 4. Therefore, a higher effect can be obtained. Further, if the stop hole 5 is a complete hole provided inside the outer edge 1E of the insulating substrate 1, when the insulating substrate 1 is cracked, the cracking is likely to stop in the stop hole 5, so that the cracking is more likely to occur. A high effect can be obtained.

Further, if the generation hole 4 is provided at a position where it overlaps with the power feeding terminal 3, when the insulating substrate 1 is cracked, cracking is likely to occur starting from the generation hole 4, so that a higher effect can be obtained. it can.

Further, if 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 both of the above-mentioned position conditions 1 and 2, when the insulating substrate 1 is cracked, Since the cracks generated starting from the generation hole 4 are likely to stop in the stop hole 5, a higher effect can be obtained.

Further, if the heating element 2 and the power feeding terminal 3 are connected to each other via the wiring 6, not only the disconnection of the heating element 2 but also the disconnection of the wiring 6 is suppressed as described above, so that the effect is higher. Can be obtained.

<1-4. Modification 1>
Regarding the heating element 2, the power supply terminal 3, the generation hole 4, and the stop hole 5, the configuration conditions such as the number and position can be arbitrarily changed.

For example, as shown in FIGS. 4 to 7 corresponding to FIG. 1C, the configuration of the heating substrate may be changed. The configuration of the heating substrate shown in FIGS. 4 to 7 is the same as the configuration of the heating substrate shown in FIG. 1C, except for the points described below. Even in the cases shown in FIGS. 4 to 7, since the cracks generated starting from the generation hole 4 stop at the stop hole 5, reliability regarding the heating operation can be ensured.

[Part 1]
In FIG. 4, for example, the stop hole 5 is arranged at a position far from the power supply terminal 3. In this case, of the above-mentioned position conditions 1 and 2, the position condition 1 is satisfied, but the position condition 2 is not satisfied. That is, the stop hole 5 is located above the median plane L, but the distance Y is larger than the distance X.

[Part 2]
In FIG. 5, for example, the stop hole 5 is arranged at a position deviated from the median plane L while maintaining the distance Y. In this case, of the above-mentioned position conditions 1 and 2, the position condition 1 is not satisfied, but the position condition 2 is satisfied. That is, the stop hole 5 is not located above the median plane L, but the distance Y is smaller than the distance X.

[Part 3]
In FIG. 6, for example, the number of power feeding terminals 3 is changed from one to two, and the number of generating holes 4 is also changed from one to two. That is, the heating substrate includes two power feeding terminals 3 (3A, 3B) and two generating holes 4 (4A, 4B). The positions of the generation holes 4A and 4B are not particularly limited as long as they are arranged so as not to overlap each other. The power feeding terminal 3A is connected to the heating element 2A via the wiring 6A, for example, and the power feeding terminal 3B is connected to the heating element 2B via the wiring 6B, for example. In this case, the above-mentioned position conditions 1 and 2 are all satisfied.

[Part 4]
In FIG. 7, for example, the number of heating elements 2 is changed from two to one, and wirings 6C and 6D are used instead of wirings 6A and 6B. The heating element 2 is arranged so that its center is located on the median plane L, for example. The stop hole 5 is arranged between the generation hole 4 and the heating element 2. The power supply terminal 3 is connected to the heating element 2 via, for example, two wires 6C and 6D. In this case, the above-mentioned position conditions 1 and 2 are all satisfied.

FIG. 8 shows the planar configuration corresponding to FIG. 7 in order to explain the problems related to the heating substrate of the second comparative example. FIG. 9 shows the planar configuration corresponding to FIG. 7 in order to explain the problems related to the heating substrate of the third comparative example.

The heating substrate of the second comparative example has the same configuration as the heating substrate shown in FIG. 7 except that the heating substrate 5 is not provided. The heating substrate of the third comparative example has the same configuration as the heating substrate shown in FIG. 7, except that the power feeding terminal 3 is connected to the heating element 2 via one wiring 6.

The problem concerning the heating substrate of the first comparative example described with reference to FIG. 2 also arises with respect to 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 cracks C4 and C5 are generated starting from the generation hole 4, the wiring 6C is broken due to the crack C4 and the wiring 6C is disconnected. The heating element 2 is disconnected due to the crack C5. Further, in the heating substrate of the third comparative example, as shown in FIG. 9, when cracks C6 and C7 occur starting from the generation hole 4, the wiring 6 is broken due to the crack C6 and the crack C7 The heating element 2 is disconnected due to the above.

On the other hand, in the heating substrate shown in FIG. 7, as described with reference to FIG. 3, even if crack C3 occurs starting from the generation hole 4, the crack C3 stops at the stop hole 5. , The disconnection of the heating element 2 and the disconnection of the wirings 6C and 6D are suppressed.

<1-5. Modification 2>
Further, for example, as shown in FIG. 10 corresponding to FIG. 1B and FIG. 11 corresponding to FIG. 1C, a groove for connecting the generation hole 4 and the stop hole 5 is provided between the generation hole 4 and the stop hole 5. 7 may be provided. Since the groove 7 is a so-called recess, it does not penetrate the insulating substrate 1.

In this case, when a crack occurs starting from the generation hole 4, the crack spreads along the groove 7, so that the crack is easily guided to the stop hole 5. Therefore, the cracks are less likely to reach the heating element 2 and the wiring 6, so that the reliability of the heating operation can be further improved.

The groove 7 may be linear, curved, or may include two or more of them. Further, the groove 7 may be bent once or more in the middle. Above all, the groove 7 is preferably a straight line along the median line L. This is because the distance of the groove 7, that is, the induction distance of the crack is the shortest, so that the crack can be more easily guided to the stop hole 5.

Conditions such as the width, depth, and cross-sectional shape of the groove 7 can be arbitrarily set. Here, for example, as shown in FIG. 10, the cross-sectional shape of the groove 7 is rectangular.

<2. Protective element>
Next, a protective element to which the heating substrate of one embodiment of the present invention is applied will be described.

The protective element described here is a so-called fuse. This protective element is mounted on an electronic device in order to cut off an electric circuit when an abnormality such as an overcurrent or an overvoltage occurs. The type of this electronic device is not particularly limited.

In particular, the protective element to which the above-mentioned heating substrate is applied has a function of interrupting an electric circuit in response to an overcurrent (circuit interruption function in a current interruption mode) and a heating substrate (heating element) in response to an abnormality such as an overvoltage. It has a function to cut off an electric circuit using 2) (a circuit cutoff function in a heater cutoff mode).

<2-1. Configuration>
12 and 13 show the cross-sectional structure of the protective element. In the following, the components of the heating substrate of the present invention already described will be cited as needed.

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

The housing 101 is the exterior of the protective element, and includes, for example, any one or more of engineering plastics and the like. This engineering plastic is, for example, polyphenylene sulfide (PPS) and liquid crystal polymer (LCP).

The shape of the housing 101 is not particularly limited, but may be, for example, a cylinder having an XY surface shape such as a circle or an ellipse, or a cube having a rectangular cross-sectional shape such as a cube or a rectangular parallelepiped.

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

Each of the external terminals 102 and 103 contains, for example, any one or more of the same conductive materials as the power feeding terminal 3, and specifically includes copper and the like. The external terminals 102 and 103 may contain the same type of material or may contain different types of materials.

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

The soluble conductor 104 self-heats in response to an overcurrent, and any one or more of the conductive materials (conductive molten materials) that can be melted by utilizing the self-heating. Includes. This conductive molten material is, for example, SnAgCu-based Pb-free solder. Further, the conductive molten material is, for example, BiPbSn alloy, BiPb alloy, BiSn alloy, SnPb alloy, PbIn alloy, ZnAl alloy, InSn alloy, PbAgSn alloy and the like.

The heating substrate 105 has the same configuration as the heating substrate of the present invention described above. However, in FIGS. 12 and 13, the illustration of the heating substrate 105 is simplified. The heating substrate 105 is arranged so 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 of the heating substrate 105. The external terminal 106 is led out to the outside through the housing 101, for example, on one end side in a direction (Y-axis direction) intersecting the extending direction of the soluble conductor 104. The external terminal 106 includes, for example, any one or more of the same conductive materials as the external terminals 102 and 103.

<2-2. Operation>
[Current cutoff mode]
This protection element performs a protection operation in the current cutoff 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 via the soluble conductor 104. In this case, the external terminals 102 and 103 and the soluble conductor 104 form a part of the electric circuit, and the external terminals 102 and 103 are in a state of being electrically conductive.

When an overcurrent (current exceeding the design value) flows in the electric circuit when using an electronic device or the like, the soluble conductor 104 self-heats (resistive heat generation) according to the overcurrent. As a result, when the soluble conductor 104 generates heat until it reaches a temperature equal to or higher than the melting point, the soluble conductor 104 melts, so that the external terminals 102 and 103 are electrically incapable of conducting electricity. Therefore, the electric circuit is cut off.

[Heater cutoff mode]
The protection element also performs a protection operation in the heater cutoff mode, for example, as described below.

For example, when a 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, the heating substrate 105 generates heat via the external terminal 106. Body 2 is powered. Details of the operation of this electronic device will be described later (see FIG. 14). When the heating element 2 self-heats in response to this power supply, the soluble conductor 104 is heated by utilizing the self-heating. As a result, when the soluble conductor 104 is heated to a temperature equal to or higher than the melting point, the soluble conductor 104 melts, so that the external terminals 102 and 103 are electrically incapable of conducting electricity. Therefore, the electric circuit is cut off.

As described above, the protection operation of the heater cutoff mode is executed when the occurrence of an abnormality is detected, and the abnormality includes not only the above-mentioned overvoltage but also other factors such as temperature rise and impact. Is also included.

<2-3. Actions and effects>
According to the above-mentioned protective element, the heating substrate 105 has the same configuration as the above-mentioned heating substrate of the present invention. In this case, as described above, even if the insulating substrate 1 is cracked when the heating substrate 105 is used, the heating element 2 can normally generate heat, so that the reliability of the heating operation is improved. Moreover, since the heating element 2 can normally generate heat, the soluble conductor 104 can be sufficiently heated by using the heating substrate 105 when an abnormality occurs, so that the reliability of the protection operation is improved. Therefore, the operational reliability of the protective element can be ensured.

The actions and effects of the other protective elements are the same as those of the heating substrate 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 protective element (electronic device)>
Next, an electronic device which is an application example of the protective element of the present invention will be described. In the following description, the components of the protective element already described will be cited as needed.

The type of electronic device to which the protective element of the present invention is applied is not particularly limited. In the following, a battery pack will be described as an example of an electronic device to which the protective element of the present invention is applied. However, the type of electronic device is not limited to the battery pack, and other electronic devices that require interruption of the electric circuit may be used as needed.

FIG. 14 shows the circuit configuration of the battery pack 200 to which the protection element is applied.

Note that FIG. 14 shows the battery pack 200 as well as the charging device 40 used to charge the battery pack 200. The battery pack 200 is removable 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 more secondary batteries 20, a detection circuit 25, a current control element 28, and a charge / discharge control circuit 30. That is, the protection element 100 is incorporated in the circuit of the battery pack 200.

The protection element 100 is arranged between the secondary battery 20 and the charge / 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 electrode terminal 26, and the external terminal 106 is connected to the current control element 28. As a result, the protective element 100 is arranged in the path through which the charging current flows when the secondary battery 20 is charged and in the path where the discharge current flows when the secondary battery 20 is discharged. Therefore, the soluble conductor 104 is secondary. It is arranged in the charge / discharge path of the battery 20.

The protective element 100 has the same configuration as the protective element of the present invention described above. That is, the protection element 100 has a circuit cutoff function in the current cutoff mode and a circuit cutoff function in the heater cutoff mode. When the protection element 100 executes the protection operation of the heater cutoff mode, the protection operation of the protection element 100 is controlled by the current control element 28.

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

The secondary battery 20 is connected to the charging device 40 via the positive electrode terminal 26 and the negative electrode terminal 27. As a result, the charging voltage can be applied from the charging device 40 to the secondary battery 20, so that the secondary battery 20 can be charged.

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

Further, the detection circuit 25 is connected to the current control element 28. The detection circuit 25 outputs a cutoff signal to the current control element 28, if necessary, based on the measurement result of the voltage of the secondary battery 20. This cutoff signal is a signal for executing the protection operation of the heater cutoff mode in the protection element 100.

The current control element 28 is a switch element used to control the operation of the protection element 100, and is, for example, a field effect transistor (FET) or the like. The current control element 28 is connected to the detection circuit 25 and is also connected to the external terminal 106 of the protection element 100.

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

Each of the current control elements 31 and 32 is, for example, a field effect transistor (FET). The current control elements 31 and 32 are arranged in the current path between the secondary battery 20 and the charging device 40, and are connected in series.

The control unit 33 operates by being supplied with electric power from the charging device 40, and controls the operations of the current control elements 31 and 32.

After charging the secondary battery 20, the battery pack 200 is detached from the charging device 40, and then another electronic device to be operated via the positive electrode terminal 26 and the negative electrode terminal 27 (hereinafter, “operation target”). It is connected to "equipment"). The type of the device to be operated is not particularly limited, but is, for example, a notebook personal computer or the like. As a result, electric power is supplied from the battery pack 200 to the operation target device, so that the operation target device can be operated.

The battery pack 200 operates, for example, as described below.

The control unit 33 determines whether or not an abnormality (overcharged state or overdischarged state) has occurred in the secondary battery 20 based on the detection result (voltage of the secondary battery 20) of the detection circuit 25. When the control unit 33 determines that an abnormality has occurred in the secondary battery 20, the control unit 33 controls the gate voltage of the current control elements 31 and 32 to cut off the supply of current to the secondary battery 20. ..

When an overcurrent exceeding the rating flows through the secondary battery 20, the protection element 100 executes the protection operation in the current cutoff mode as described above. That is, since the soluble conductor 104 melts in the protective element 100, the current path between the secondary battery 20 and the charging device 40 is cut off.

Further, 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 an abnormality has occurred in the secondary battery 20, it outputs a cutoff signal to the current control element 28.

When the cutoff signal is output from the detection circuit 28, the protection element 100 executes the protection operation of the heater cutoff mode as described above. That is, the current control element 28 can supply a current to the protection element 100. In this case, when a current is supplied from the secondary battery 20 to the heating element 2 via the external terminal 106, the heating element 2 generates heat, so that the soluble conductor 104 is heated by the heating element 2. As a result, the soluble conductor 104 melts, so that the current path between the secondary battery 20 and the charging device 40 is cut off regardless of the operation of the current control elements 31 and 32.

According to the battery pack 200 described above, the protective element 100 has the same configuration as the protective element of the present invention. In this case, as described above, the reliability of the heating operation is high, so that the reliability of the protection operation is also high. Therefore, the reliability of the protective operation can be ensured. Other actions and effects are the same as those of the protective element of the present invention.

Specific examples of the present invention will be described in detail.

(Examples 1 and 2)
The protective elements shown in FIGS. 12 and 13 were manufactured by the following procedure.

First, an alumina ceramic substrate was prepared, and then the alumina ceramic substrate was perforated using a laser to form generation holes 4 and stop holes 5. As a result, the insulating substrate 1 was obtained.

In this case, the planar shape of the generation hole 4 is made circular, and the generation hole 4 is made into a through hole and an incomplete hole. The planar shape of the stop hole 5 was made circular, and the stop hole 5 was made into a through hole and a complete hole. The stop hole 5 was arranged on the median plane L with reference to the generation hole 4. The inner diameter of the generation hole 4 was 0.5 mm, the inner diameter of the stop hole 5 was 0.65 mm, the distance X = 2 mm, and the distance Y = 1.8 mm.

Subsequently, a heating element 2 (ruthenium oxide), a feeding terminal 3 (silver), and a wiring 6 (silver) were each patterned on the insulating substrate 1. In this case, a paste containing each material such as ruthenium oxide was printed on the surface of the insulating substrate 1 as a thick film, and then the thick film was fired.

As a result, the heating substrate 105 shown in FIGS. 1A to 1C was completed. 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.

Subsequently, the external terminals 102 and 103 are connected to each other via the soluble conductor 104, and the external terminal 106 is connected to the heating substrate 105 (feeding terminal 3), and then the heating element 2 is adjacent to the soluble conductor 104. The heating substrate 105 was arranged so as to do so. Finally, the external terminals 102, 103, 106, the soluble conductor 104, and the heating substrate 105 were housed inside the housing 101. As a result, the protective element was completed. The configuration of the main part of the protective element (presence / absence of generation hole 4 and presence / absence of stop hole 5) is as shown in Table 1.

When the operating characteristics (heater cutoff mode) of the protective element were examined, the results shown in Table 1 were obtained. When examining this operating characteristic, power (maximum 120 W) is supplied between the external terminals 102 and 103 and the external terminals 106 in a state where the external terminals 102 and 103 are short-circuited outside the housing 101. , The heating substrate 105 (heating element 2) was heated. As a result, it was visually inspected whether or not the soluble conductor 104 was melted, and the insulation resistance (Ω) was measured using a tester.

The protective element behaved completely differently depending on the presence or absence of the stop hole 5.

Specifically, when the stop hole 5 was not formed (Experimental Example 2), when a crack occurred starting from the generation hole 4, the crack reached the heating element 2. In this case, since the heating element 2 could not normally self-heat, the soluble conductor 104 was not sufficiently heated by the heating element 2. Therefore, since the soluble conductor 104 was not sufficiently melted, the insulation resistance did not increase.

On the other hand, when the stop hole 5 was formed (Experimental Example 1), when a crack occurred starting from the generation hole 4, the crack stopped at the stop hole 5 and did not reach the heating element 2. In this case, since the heating element 2 was able to normally self-heat, the soluble conductor 104 was sufficiently heated by the heating element 2. Therefore, since the soluble conductor 104 was sufficiently melted, the insulation resistance was remarkably increased.

From the results shown in Table 1, when the insulating substrate 1 was provided with the generation hole 4 and the stop hole 5, the electric circuit was cut off during the protection operation of the heater cutoff mode. Therefore, the reliability of the heating operation of the heating substrate 105 is ensured, and the protective operation of the protective element on which the heating substrate 105 is mounted is also ensured.

Although the present invention has been described above with reference to embodiments and examples, the present invention is not limited to the embodiments described in the embodiments and examples, and various modifications can be made. For example, the configuration of the heating substrate and the configuration of the protective element are not limited to the configurations described in the above-described embodiment, and may be appropriately changed.

1 ... Insulating substrate, 1E ... Outer edge, 2 ... Heating element, 3 ... Power supply terminal, 4 ... Generation hole, 5 ... Stop hole, 6 ... Wiring, 7 ... Groove, 102, 103 ... External terminal, 104 ... Soluble conductor , 105 ... Heating substrate.

Claims (15)

A heating element is provided on one surface of the insulating substrate provided with the first hole and the second hole.
The second hole is arranged at a position that prevents cracks in the insulating substrate generated in the first hole from reaching the heating element .
Further, it is provided with a power supply terminal for supplying an electric current to the heating element.
The first hole is located closer to the heating element than the heating element, and the second hole is located closer to the heating element than the heating terminal.
Heating substrate. At least one of the first hole and the second hole is a through hole.
The heating substrate according to claim 1. The first hole is a notch-shaped incomplete hole provided on the outer edge of the insulating substrate.
The second hole is a complete hole provided inside the outer edge of the insulating substrate.
The heating substrate according to claim 1 or 2. The first hole is provided at a position overlapping the power feeding terminal.
The heating substrate according to any one of claims 1 to 3. The positional relationship between the heating element, the power feeding terminal, the first hole and the second hole satisfies at least one of the following two conditions.
Heating the substrate according to any one of claims 1 to claim 4.
Condition 1: The second hole is located on the median line of the insulating substrate with reference to the position of the first hole.
Condition 2: The distance between the first hole and the second hole is smaller than the distance between the first hole and the heating element. Further, a wiring for connecting the heating element and the power feeding terminal is provided on one surface of the insulating substrate.
Heating the substrate according to any one of claims 1 to 5. A groove for connecting the first hole and the second hole is provided on one surface of the insulating substrate.
The heating substrate according to any one of claims 1 to 6. With two external terminals connected to each other via a soluble conductor,
A heating substrate for melting the soluble conductor is provided.
The heating substrate is provided with a heating element on one surface of an insulating substrate provided with a first hole and a second hole.
The second hole is arranged at a position that prevents cracks in the insulating substrate generated in the first hole from reaching the heating element .
Further, it is provided with a power supply terminal for supplying an electric current to the heating element.
The first hole is located closer to the heating element than the heating element, and the second hole is located closer to the heating element than the heating terminal.
Protective element. At least one of the first hole and the second hole is a through hole.
The protective element according to claim 8. The first hole is a notch-shaped incomplete hole provided on the outer edge of the insulating substrate.
The second hole is a complete hole provided inside the outer edge of the insulating substrate.
The protective element according to claim 8 or 9. The first hole is provided at a position overlapping the power feeding terminal.
The protective element according to any one of claims 8 to 10. The positional relationship between the heating element, the power feeding terminal, the first hole and the second hole satisfies at least one of the following two conditions.
The protective element according to any one of claims 8 to 11.
Condition 1: The second hole is located on the median line of the insulating substrate with reference to the position of the first hole.
Condition 2: The distance between the first hole and the second hole is smaller than the distance between the first hole and the heating element. The heating substrate further includes wiring for connecting the heating element and the power supply terminal on one surface of the insulating substrate.
The protective element according to any one of claims 8 to 12. A groove for connecting the first hole and the second hole is provided on one surface of the insulating substrate.
The protective element according to any one of claims 8 to 13. Equipped with a protective element that cuts off the electric circuit when an abnormality occurs
The protective element is
With two external terminals connected to each other via a soluble conductor,
A heating substrate for melting the soluble conductor is provided.
The heating substrate is provided with a heating element on one surface of an insulating substrate provided with a first hole and a second hole.
The second hole is arranged at a position that prevents cracks in the insulating substrate generated in the first hole from reaching the heating element .
Further, it is provided with a power supply terminal for supplying an electric current to the heating element.
The first hole is located closer to the heating element than the heating element, and the second hole is located closer to the heating element than the heating terminal.
Electronics.

Images