KR20190050851A - Protective element - Google Patents

Abstract

Provided is a protection device capable of suppressing occurrence of cracks in an insulating substrate by appropriately arranging a distance between a through hole and a heating element. A heating element 14 formed between a pair of side edges 10c and 10d facing each other of the insulating substrate 10 and a pair of side edges 10c and 10d of the insulating substrate 10 A first heating element electrode 18 which is formed on one side edge 10c side and which is electrically connected to the heating element 14 and on which the hole portion 25 is formed and a second heating element electrode 18 on the other side of the pair of side edges 10c and 10d A second heating element electrode 19 which is formed on the side edge 10d side and is electrically connected to the heating element 14 and a usable conductor 13 which is fused by heat generation of the heating element 14 and blocks the current path And the center C1 of the heating element 14 is biased from the middle position C2 of the distance between the pair of side edges 10c and 10d of the insulating substrate 10 toward the other side edge 10d.

Description

Protective element

The present invention relates to a protection element for shielding a power supply line or a signal line. The present application claims priority based on Japanese Patent Application No. 2016-219891, filed on November 10, 2016, which is incorporated herein by reference in its entirety.

Many of the secondary batteries that can be charged and used repeatedly are processed into battery packs and provided to the user. Particularly, in a lithium ion secondary battery having a high weight energy density, in order to secure the safety of users and electronic equipment, various protection circuits such as overcharge protection and over discharge protection are generally incorporated in the battery pack, And the output of the battery pack is cut off.

Such a type of protection element may be provided with an FET (Field Effect Transistor) switch incorporated in the battery pack to turn on / off the output to perform the overcharge protection or the over-discharge protection operation of the battery pack. However, when the FET switch is short-circuited for some reason, an instantaneous large current flows due to a brain surge or the like, or the output voltage is ideally lowered due to the life of the battery cell, or an excessive abnormal voltage is output Even in such a case, the battery pack or the electronic device must be protected from accidents such as ignition. In order to safely shut off the output of the battery cell, a protective element having a function of shutting off the current path by an external signal is used even in such an abnormal state that can be assumed.

12 (A) and (B), the first electrode 91, the heating-element lead-out electrode 95, the second electrode 92 And a part of the current path is formed by connecting the usable conductor 93 to the usable conductor 93 so that the usable conductor 93 on the current path is fused by the self heating by the overcurrent or the heating element 94 formed inside the protective element (See Patent Document 1). In such a protective element 90, the molten liquid soluble conductor 93 is gathered on the heating-element lead-out electrode 95 leading to the heating element 94 and on the first and second electrodes 91 and 92, And the second electrodes 91 and 92 to disconnect the current path.

In the protection element, the usable conductor 93 is fused by the heat generated by the heating element 94, and the usable conductor 93 is fused by the self-heating by the overcurrent, so that the fused usable conductor 93 is not scattered And is covered with a cover member 97 which is an external component. The protective element 90 has an inner space for melting and flowing the usable conductor 93 by the cover member 97 in order to stably realize the melting action of the usable conductor 93 by the heating element 94, Respectively.

The protective element 90 is also coated with a flux 98 for preventing the oxidation of the surface of the usable conductor 93 and removing the oxide film on the surface of the usable conductor 93 in order to maintain the fastness.

Japanese Laid-Open Patent Publication No. 2015-35281

Such a surface mount type protection device is required to improve the current rating in accordance with the increase in the capacity of the electronic device and the battery pack to be mounted and the increase in the fixing strength. At the same time, in portable electronic devices, further downsizing is required.

In order to increase the current rating, a usable conductor having a larger volume is adopted. On the other hand, in order to obtain a calorific value for quickly fusing a large usable conductor, a heating element having a considerable size is required.

When the heating value of the heating element is increased in the conventional type protection element, cracks may be formed in the insulating substrate due to thermal shock due to heat generation. In some cases, cracks are also formed in the heating element, There is a danger that the fusion may occur.

Here, in the conventional type protection device, three electrodes of a first and a second electrode connected to both ends of a usable conductor and a heating element electrode for conducting electricity to the heating element are arranged on the surface of an insulating substrate on which a heating element is mounted in a substantially central portion . These three electrodes are respectively connected to external electrodes formed on the back surface of the insulating substrate through half-through holes formed in side edge portions of the insulating substrate (see Patent Document 1).

Observation of the protective element in which cracks were formed by the heat generation of the heating element revealed that cracks were formed starting from the through holes of the heating element electrode. The through-hole of the heating-element electrode is disposed closer to the heating element than the other two electrodes, that is, the through-hole formed in the first and second electrodes. The through-hole is arranged in such a way that the heating- It is thought to be the cause.

As a result of recent miniaturization of the protection device, the distance between the through hole and the heating element becomes smaller than in the conventional product, and the protection element is more susceptible to thermal shock caused by the heating element.

Therefore, the object of the present invention is to provide a protective device capable of suppressing occurrence of cracks in an insulating substrate by appropriately arranging the distance between the through holes and the heat generating element.

In order to solve the above-described problems, a protective element related to the present invention includes an insulating substrate, a heating element formed between a pair of side edges of the insulating substrate opposite to each other, A first heating element electrode which is formed on one side of the side edge of the side edge and is electrically connected to the heating element and has an opening formed therein and a second heating element electrode which is formed on the other side edge of the pair of side edges and which is electrically connected to the heating element A heating element electrode; and a usable conductor which is fused by the heat generated by the heating element and blocks the current path, the center of the heating element is a center of the distance from the one side edge of the insulating substrate to the other side edge To the side of the other side.

According to this technology, the protection element is capable of preventing the generation of a crack due to a weak thermal shock due to the heat generation of the heating element with respect to the region of the end portion of the one side of the side of the heating element.

1 is an external perspective view showing a protective element to which the present technology is applied.
2 is a cross-sectional view showing a circuit module to which the present technology is applied.
3 is a plan view showing the surface of the insulating substrate of the protection element with the cover member omitted.
4 is an external perspective view showing a protective element to which the present technology is applied from the back side.
5 is a plan view showing a protective element in which a hole is formed in the third side edge and the fourth side edge.
6 is a plan view showing the center of the insulating substrate and the center of the heat generating element.
7 is a plan view showing a region for measuring the size of each constitution of the protection element.
8 is a plan view showing a protection element having a through hole formed slightly inward from the third side edge as a hole portion formed in the first heating element electrode.
9 is a plan view showing a protection element having a through hole formed slightly inward from the castellation and the third side edge formed at the third side edge as a hole portion formed in the first heating element electrode.
10 is a circuit diagram showing a configuration example of a battery circuit using a fuse element to which the present invention is applied.
11 is a circuit diagram of a fuse element to which the present invention is applied.
Fig. 12 is a view showing a conventional protection element, wherein (A) is a plan view showing the cover member omitted, and Fig. 12 (B) is a sectional view.

Hereinafter, a protection device to which the present technology is applied will be described in detail with reference to the drawings. It should be noted that the present technology is not limited to the following embodiments, and various modifications can be made within the scope not departing from the gist of the present invention. In addition, the drawings are schematic, and the ratios of respective dimensions and the like may be different from the reality. The specific dimensions and the like should be judged based on the following description. Needless to say, the drawings also include portions where the relationship and the ratio of the dimensions are different from each other.

[Protection Device]

As shown in Figs. 1 and 2, the protection device 1 to which the present invention is applied constitutes the circuit module 3 by being surface-mounted on the circuit board 2. Fig. In the circuit board 2, for example, a protection circuit for a lithium ion secondary battery is formed, and the protection element 1 is mounted on the surface, so that the usable conductor 13 is mounted on the charging / discharging path of the lithium ion secondary battery . When the large current exceeding the rating of the protection element 1 flows, the circuit module 3 cuts off the current path as the usable conductor 13 is fused by self-heating (juxtaposition). The circuit module 3 energizes the heating element 14 at a predetermined timing by the current control element formed on the circuit board 2 or the like and fuses the usable conductor 13 by the heating of the heating element 14, You can block the path.

2 is a cross-sectional view showing a part of a circuit module 3 in which the protection element 1 is mounted on a circuit board 2, and FIG. 2 is a cross- 3 is a plan view showing the surface 10e of the insulating substrate 10 of the protection element 1 with the cover member 20 omitted and Fig. 4 is an external perspective view showing the back surface side of the protection element 1 .

1 to 4, the protection element 1 includes an insulating substrate 10, a heating element 14 laminated on the insulating substrate 10 and covered with an insulating member 15, A first electrode 11 and a second electrode 12 formed on the first and second side edges 10a and 10b of the heating element 14 and the heating element 14, And a usable conductor 13 connected at both ends to the first and second electrodes 11 and 12 and connected to the heating element lead-out electrode 16 at the center.

[Insulation Substrate]

The insulating substrate 10 is formed in a substantially circular shape by an insulating member such as alumina, glass ceramics, mullite, or zirconia, for example. As the insulating substrate 10, a material used for a printed wiring board such as a glass epoxy substrate or a phenol substrate may be used.

The insulating substrate 10 is formed in a rectangular shape and includes first and second side edges 10a and 10b facing each other where the first electrode 11 and the second electrode 12 are formed, And third and fourth side edges 10c and 10d facing each other where the first and second heating element electrodes 18 and 19 are formed adjacent to the second side edge.

[First and Second Electrodes]

The first and second electrodes 11 and 12 are opened by being disposed apart from each other in the vicinity of the side edges 10a and 10b facing each other on the surface 10e of the insulating substrate 10, 13 are mounted and electrically connected via the usable conductor 13. The first and second electrodes 11 and 12 are formed in such a manner that a large current exceeding the rated value flows in the protective element 1 so that the usable conductor 13 is fused by self- It is heated due to the energization, and the usable conductor 13 is fused so as to be cut off.

2, the first and second electrodes 11 and 12 are formed on the back surface 10f through a castellation formed on the first and second side edges 10a and 10b of the insulating substrate 10, respectively, And is connected to the external connection electrodes 11a and 12a formed on the substrate. The protection element 1 is connected to a circuit board 2 on which an external circuit is formed via these external connection electrodes 11a and 12a and constitutes a part of a current carrying path of the external circuit.

The first and second electrodes 11 and 12 can be formed using common electrode materials such as Cu and Ag. On the surfaces of the first and second electrodes 11 and 12, a coating film of Ni / Au plating, Ni / Pd plating, Ni / Pd / Au plating or the like is coated by a known technique such as a plating treatment desirable. As a result, the protection element 1 can prevent the first and second electrodes 11 and 12 from being oxidized, and can prevent the fluctuation in the rating due to the increase in the conduction resistance. When the protection element 1 is reflow-soldered, the solder for connection or the low-melting-point metal forming the outer layer of the usable conductor 13 is melted to connect the usable conductor 13 to the first and second electrodes 11, 12 can be prevented from being melted (soldering).

[Heating element]

The heat generating element 14 is made of, for example, W, Mo, Ru, Cu, Ag, or an alloy containing these as the main component. The heat generating element 14 can be formed by mixing these alloys, the composition, and the compound powder with a resin binder or the like and forming a paste into a pattern on the insulating substrate 10 using a screen printing technique and firing have. The heating element 14 is formed in a substantially rectangular shape having long sides between the third and fourth side edges 10c and 10d and has one end in the width direction formed on the side of the third side edge 10c, And the other end in the width direction is connected to the second heating element electrode 19 formed on the side of the fourth side edge 10d.

The protection element 1 is provided with an insulating member 15 so as to cover the heating element 14 and a heating element lead-out electrode 16 is formed so as to face the heating element 14 via the insulating member 15 . The protection element 1 may also be laminated with the insulating member 15 between the heating element 14 and the insulating substrate 10 in order to efficiently transfer the heat of the heating element 14 to the usable conductor 13. [ As the insulating member 15, for example, glass can be used.

One end of the heating-element lead-out electrode 16 is connected to the second heating-element electrode 19 and is connected to one end of the heating-element 14 via the second heating-element electrode 19. The first heating element electrode 18 is formed on the side of the third side edge 10c and the connection side 18a connected to one long side of the heating element 14 is formed along the longitudinal direction of the insulating substrate 10 have. Similarly, the second heating element electrode 19 is formed on the side of the fourth side edge 10d, and the connection side 19a connected to the other long side of the heating element 14 is formed along the longitudinal direction of the insulating substrate 10 Respectively.

The first heating element electrode 18 is connected to the external connecting electrode 18b formed on the back surface 10f of the insulating substrate 10 through the hole 25. [ The hole portion 25 may be formed as a castellation formed on the third side face 10c as shown in Fig. 3, or may be formed as a through hole formed slightly inward from the third side face 10c, The through hole and the through hole may be used in combination. One or a plurality of the hole portions 25 may be formed.

As described above, the protection element 1 is formed in an asymmetrical shape in which the hole portion 25 is formed in only one of the first and second heating element electrodes 18 and 19. The second exothermic electrode 19 connected to the exothermic body lead-out electrode 16 has higher heat capacity and higher resistance to thermal shock than the first exothermic body electrode 18 having the hole 25 formed therein.

5, the protection element to which the present technology is applied is not limited to a castellation formed on the fourth side edge 10d of the second heating element electrode 19 nor a through hole formed slightly on the inner side from the fourth side edge 10d Hole 26 may be formed. The second heating element electrode 19 is connected to the external connection electrode formed on the back surface 10f of the insulating substrate 10 through the hole portion 26. [ The protection element 27 shown in Fig. 5 is formed in a symmetrical shape by forming the hole portions 25 and 26 in the first and second heating element electrodes 18 and 19. The hole 26 formed in the second heating element electrode 19 of the protection element 27 may be formed as a castellation or a through hole as shown in Fig. 5, or may be formed as a cast- . One or a plurality of the hole portions 26 may also be formed.

The heating element 14 is connected to an external circuit formed on the circuit board 2 via the external connection electrode 18b and the first heating element electrode 18 by mounting the protection element 1 on the circuit board 2 . The heating element 14 is energized and generated by way of the external connection electrode 18b and the first heating element electrode 18 at a predetermined timing for blocking the energizing path of the external circuit so that the first and second electrodes 11 , 12 can be fused. Further, in the heating element 14, since the usable conductor 13 is fused, its own current supply path is also blocked, so that the heat generation is stopped.

[Available conductor]

The usable conductor 13 is made of a material that rapidly fuses by heat generation of the heating element 14, and for example, a low melting point metal such as solder or Pb-free solder containing Sn as a main component can be preferably used.

The usable conductor 13 may be a refractory metal such as In, Pb, Ag, Cu or an alloy mainly composed of any of them, or may be a laminate of a refractory metal and a refractory metal. By containing the high-melting-point metal and the low-melting-point metal, even if the reflowing temperature exceeds the melting temperature of the low-melting-point metal and the low-melting-point metal is melted, So that the shape of the usable conductor 13 can be maintained. Also, at the time of melting, melting of the low melting point metal enables melting at a temperature not higher than the melting point of the high melting point metal by melting (melting) the high melting point metal.

The usable conductor 13 is connected to the heating element lead-out electrode 16 and the first and second electrodes 11 and 12 by solder or the like. The usable conductor 13 can be easily connected by reflow soldering.

It is preferable that the usable conductor 13 is coated with the flux 17 in order to prevent oxidation and improve wettability.

[Cover member]

In order to protect the inside of the protection element 1, a cover member 20 is formed on the surface 10e of the insulating substrate 10. The cover member 20 is formed in a substantially rectangular shape depending on the shape of the insulating substrate 10. [ 1, the cover member 20 includes a side surface 21 connected to the surface 10e of the insulating substrate 10 on which the usable conductor 13 is formed, And the surface 10e of the insulating substrate 10 which covers the upper surface 10e of the insulating substrate 10 so that the usable conductor 13 expands spherically when molten and the molten conductor reaches the heating element lead- And has an inner space sufficient to flocculate onto the first and second electrodes 11, 12.

The side surface 21 of the cover member 20 is connected to the surface 10e of the insulating substrate 10 by an adhesive or by welding or the like. As the adhesive for connecting the cover member 20, a thermosetting adhesive excellent in connection reliability can be preferably used.

[Manufacture process]

Next, the manufacturing process of the protection element 1 will be described. First, the first and second electrodes 11 and 12, the heating element 14, the first and second heating element electrodes 18 and 19, the insulating member 15, and the heating element 15 are drawn out from the surface 10e of the insulating substrate 10 Electrode 16 is formed. The external connection electrodes 11a, 12a and 18b are formed on the back surface 10f of the insulating substrate 10 and the first and second electrodes 11 and 12 are formed through the casting or the hole 25, And the first heating element electrode 18, as shown in Fig. Then, the usable conductor 13 is mounted across the first and second electrodes 11 and 12 via the heating-element lead-out electrode 16. Then, Connection solder may be supplied between the usable conductor 13 and the first and second electrodes 11 and 12 and the heating-element lead-out electrode 16.

Then, the cover member 20 is connected on the surface 10e of the insulating substrate 10. Then, The connection of the cover member 20 is preferably performed by supplying a thermosetting adhesive excellent in connection strength to the lower portion of the side surface 21. [

The structure in which the cover member 20 is mounted on the surface 10e of the insulating substrate 10 is heated so that the usable conductor 13 is electrically connected to the first and second electrodes 11 and 12 And the cover member 20 is connected to the surface 10e of the insulating substrate 10 so that the protection element 1 is formed . The protection element 1 is mounted on a circuit board 2 on which a power supply circuit or the like is formed by reflow or the like to form the circuit module 3. [

[Matching of the center of the usable conductor and the heat generating center of the heating element]

At this time, the protective element 1 preferably mounts the usable conductor 13 so that the center of the usable conductor 13 and the heat generating center of the heating element 14 overlap. The center of the usable conductor 13 is the center of gravity of the usable conductor 13 in the usable conductor 13 formed of a rectangular plate. The exothermic center of the exothermic body 14 is a position that becomes the highest temperature at the initial stage of exothermic heating and becomes the center of gravity position of the exothermic body 14 in the exothermic body 14 formed in a rectangular shape.

The center of the usable conductor 13 is superimposed on the exothermic center of the exothermic body 14 and mounted so that the heat of the exothermic body 14 is efficiently transferred to the usable conductor 13 and the usable conductor 13 is quickly fused . In addition, the heat of the heating element 14 is efficiently transmitted to the usable conductor 13, so that the insulating substrate 10 and the heating element 14 themselves can be prevented from being overheated, and occurrence of cracks can be suppressed.

[Arrangement of each department]

Here, the amount of heat generated by the heat generating element 14 increases with the size of the heat generating element 14. The hole 25 formed in the first heating element electrode 18 is relatively close to the heating element 14 and is susceptible to the thermal impact accompanied by the heat generation of the heating element 14. [ For this reason, in order to obtain a heating value for quickly melting the large-capacity usable conductor 13 by the heating element 14 while using the larger-sized usable conductor 13 in response to the demand for the higher capacity of the protection element 1, A crack may be generated in the insulating substrate or the heating element 14 toward the hole portion 25 by the impact. Since the heat generation at the cracked portion of the heat generating element 14 is stopped, a desired heat generation amount can not be obtained, and the fusing time of the usable conductor 13 may be extended.

Thus, the protective element 1 is arranged so that the constituent parts constituting the protective element 1 such as the heating element 14 and the hole part 25 are appropriately arranged, so that the heat generated in the heating element 14 It is possible to prevent a crack from being generated toward the hole portion 25 due to the impact.

Specifically, as shown in Fig. 6, the protective element 1 is formed so that the heat generating center 14 of the heat generating element 14 is located at the center of the third side edge 10c to the fourth side edge 10d of the insulating substrate 10 Is formed to be offset from the position (C2) in the middle of the distance toward the side of the side where the heating element electrode having a large heat capacity among the first and second heating element electrodes (18, 19) is formed. As described above, in the protection element 1, since the heating element lead-out electrode 16 is formed in the second heating element electrode 19 and the hole portion 25 is not formed, The heat capacity is larger than that of the first heating electrode 18 formed. The protective element 1 is formed such that the exothermic center C1 of the exothermic body 14 is biased toward the fourth side edge 10d side where the second exothermic electrode 19 is formed.

As a result, in the protection element 1, the thermal shock due to the heat generation of the heating element 14 with respect to the region of the end portion of the hole portion 25 and the third side edge 10c side of the heating element 14 is weakened, . In the symmetrical protective element 27 in which the hole 26 is also formed in the second heating element electrode 19 shown in Fig. 5, the heating center of the heating element 14 is connected to the first and second heating element electrodes 18, 19, the heating element electrode having a large heat capacity is formed.

The protection element 1 is formed such that the dimensions of the respective portions in the plan view of the protection element 1 shown in Fig. 7 are defined as follows, and the conditions shown in the first to seventh embodiments described below are satisfied .

A: the shortest distance between the third side edge 10c of the insulating substrate 10 and the end of the third side edge 10c side of the heat generating element 14

B is the shortest distance between the end on the third side edge 10c side of the heating element 14 and the outer edge of the hole 25 formed in the first heating element electrode 18,

C is the shortest distance between the fourth side edge 10d of the insulating substrate 10 and the end of the fourth side edge 10d side of the heating element 14

D: a center line parallel to the third and fourth side edges 10c and 10d passing through the center between the third and fourth side edges 10c and 10d of the insulating substrate 10 and the third side edge 10c of the heating element 14, The distance

E: a center line parallel to the third and fourth side edges 10c and 10d passing through the center between the third and fourth side edges 10c and 10d of the insulating substrate 10 and the fourth side edge 10d of the heating element 14, The distance

F: distance between the third and fourth side edges 10c and 10d of the insulating substrate 10

G: Width of the heating element 14 formed in a substantially rectangular shape

H: distance between the first and second side edges 10a and 10b adjacent to the third and fourth side edges 10c and 10d of the insulating substrate 10

In this case, when the number of the hole portions 25 is plural, the end portion of the heat emitting body 14 on the side of the third side edge 10c and the outer portion of the hole portion 25 located on the side of the heat emitting body 14 . 8 is a plan view showing a protection element 1 having a through hole formed slightly inward from the third side edge 10c as a hole portion 25 to be formed in the first heating element electrode 18. Fig. In the protection element 1 shown in Fig. 8, the outer edge of the hole 25 becomes the outer edge of this through hole.

9 is a sectional view of the hole portion 25 formed in the first heating element electrode 18 and showing a castellation formed on the third side edge 10c and a through hole formed slightly inward from the third side edge 10c Fig. 1 is a plan view showing a protection element 1 having a protection film 1 shown in Fig. In the protection element 1 shown in Fig. 9, the outer edge of the hole portion 25 is the outer edge of the through hole located closest to the heat generating element 14 side.

In the symmetrical protection element 27 in which the hole portion 25 is formed in the first heating element electrode 18 and the hole portion 26 is formed in the second heating element electrode 19, B is the distance between the outer edge of the hole portion in which the heating element electrode having the smaller heat capacity is formed and the side edge where the heating element electrode is formed among the two heating element electrodes 18 and 19 and the third and fourth side edges 10c and 10d, C is the distance between the outer edge of the hole portion where the larger heating element electrode is formed and the side edge where the heating electrode is formed.

[First embodiment: B / (D + E)]

The protective element 1 preferably has B / (D + E) of 0.20 or more. That is, the protective element 1 is formed so that the end portion of the heating element 14 on the side of the third side edge 10c and the hole portion formed in the first heating element electrode 18 The ratio of the shortest distance B of the outer edges of the projections 25 is preferably not less than 0.20.

The amount of heat generated by the heat generating element 14 is increased according to the length D + E of the heat generating element 14. The longer the distance from the heat generating element 14 to the hole 25 is, the greater the resistance against cracking becomes. When the ratio of the distance B from the heating element 14 to the hole 25 to the length D + E of the heating element 14 is 0.20 or more, resistance to the heating value of the heating element 14 is increased , It is possible to prevent the occurrence of a crack toward the hole portion (25).

On the other hand, when the ratio of the distance B from the heating element 14 to the hole 25 to the length D + E of the heating element 14 is less than 0.20, the length D + E of the heating element 14 The distance between the heat generating element 14 and the hole portion 25 is short and the resistance to thermal shock is insufficient and cracks may occur.

[Second embodiment: B / G]

It is preferable that the protective element 1 has B / G of 1.0 or more. That is, the protective element 1 is formed so that the edge of the heating element 14 on the side of the third side edge 10c and the edge of the outer edge of the hole 25, with respect to the width G of the heating element 14 formed in a substantially rectangular shape, And the ratio of the distance (B) is 1.0 or more.

The amount of heat generated by the heat generating element 14 also increases with the width G of the heat generating element 14 and the heat transfer route toward the hole 25 becomes wider as the width increases. The longer the distance from the heating element 14 to the hole 25, the greater the resistance to cracking. Therefore, by setting the ratio of the distance B from the heating element 14 to the hole 25 to the width G of the heating element to 1.0 or more, resistance against the heating amount of the heating element 14 is provided, It is possible to prevent the occurrence of a crack toward the second substrate 25.

On the other hand, when the ratio of the distance B from the heating element 14 to the hole 25 to the width G of the heating element is less than 1.0, the heating element 14 and the hole The distance to the portion 25 is short, resistance to thermal shock is insufficient, and cracks may occur.

[Third embodiment: B / (G / (D + E))]

It is preferable that the protective element 1 has B / (G / (D + E)) of 6.0 or more. In other words, the protective element 1 is formed on the third side edge 10c (10e) of the heating element 14 with respect to the aspect ratio G / (D + E) of the width G of the heating element 14 and the length D + (B) of the outer edge of the hole 25 is 6.0 or more.

If the shortest distance B between the end of the heating element 14 on the side of the third side edge 10c and the outer edge of the hole 25 is large in the insulating substrate 10 of a predetermined size, The distance of the length D + E of the heating element 14 formed across the four side edges 10c and 10d is shortened and the amount of heat generation is reduced. When the width G of the heat generating element 14 is reduced, the amount of heat generated is reduced.

Therefore, in the insulating substrate of a predetermined size, the distance from the exothermic body 14 to the hole (G + D + E) of the width (G) and the length (D + E) 25, the resistance to the heat generation amount of the heating element 14 can be provided. More specifically, the distance B from the heating element 14 to the hole 25 with respect to the aspect ratio G / (D + E) of the width G of the heating body 14 and the length D + By setting the ratio to 6.0 or more, resistance to the heat generation of the heat generating element 14 is provided, and occurrence of a crack toward the hole portion 25 can be prevented.

The ratio of the distance B from the heating element 14 to the hole 25 with respect to the aspect ratio G / (D + E) of the width G of the heating body 14 and the length D + Is less than 6.0, the distance from the heating element 14 to the hole portion 25 is shorter than the length (D + E) of the heating element 14 and the width G of the heating element 14, There is a possibility that cracks may occur.

[Fourth Embodiment: B / (B + D + E + C)]

It is preferable that the protective element 1 has B / (B + D + E + C) of 0.15 or more. That is to say, the end portion on the side of the third side edge 10c of the heating element 14 with respect to the distance B + D + E + C from the outer edge of the hole portion 25 to the fourth side edge 10d, The ratio of the shortest distance B of the outermost edge of the light emitting layer to the light emitting layer is preferably 0.15 or more.

The insulating substrate 10 is formed with the hole portion 25 on the side of the third side edge 10c so that the resistance against thermal shock from the heat generating body 14 of the insulating substrate 10 to the hole portion 25 The distance from the outer edge of the hole portion 25 to the fourth side edge 10d (that is, the distance from the third side edge 10c of the insulating substrate 10 to the hole 25) B + D + E + C) can be regarded as the length of the insulating substrate 10 which is substantially subjected to the thermal shock of the heating element 14. The third side edge of the heating element 14 at the distance (B + D + E + C) from the outer edge of the hole portion 25 to the fourth side edge 10d to receive the thermal impact of the heating element 14 10c and the shortest distance B between the outer edge of the hole 25 and the outer edge of the hole 25 is greater, resistance to the heat generated by the heating element 14 can be provided. Specifically, by setting the ratio B / (B + D + E + C) to 0.15 or more, resistance against the heat generation amount of the heat generating element 14 is provided, and occurrence of cracks toward the hole portion 25 can be prevented.

On the other hand, the end of the heating element 14 on the third side edge 10c side at the distance (B + D + E + C) from the outer edge of the hole 25 to the fourth side edge 10d and the end of the hole 25 (B + D + E + C) of the insulating substrate 10 when the ratio of the shortest distance B between the heating element 14 and the hole 25 is less than 0.15 Is short, resistance to heat shock is insufficient, and cracks may occur.

[Fifth Embodiment: B / C]

It is preferable that the protective element 1 has B / C of 0.9 or more. That is, in the insulating substrate 10 of a predetermined size, the distance between the fourth side edge 10d of the insulating substrate 10 and the shortest distance C of the end on the fourth side edge 10d side of the heat emitting body 14 14 to the shortest distance B between the end on the side of the third side edge 10c and the outer edge of the hole 25 is 0.9 or more.

When the length D + E of the heating element 14 occupied between the third and fourth side edges 10c and 10d of the surface 10e of the insulating substrate 10 is made constant, both ends of the heating element 14 The shortest distance B between the outer edge of the hole portion 25 and the fourth side edge 10d is set to 0.9 or more so that the shortest distance B from the outer edge of the hole portion 25 is set to be 0.9 or more, It is possible to prevent the occurrence of cracks toward the hole portion 25 by improving the resistance to thermal shock of the region reaching the hole portion 25 where cracks tend to occur.

On the other hand, in the surface 10e of the insulating substrate 10, the shortest distance C between the fourth side edge 10d of the insulating substrate 10 and the fourth side edge 10d side of the heat generating body 14 When the ratio of the end portion on the third side edge 10c side of the heat generating element 14 to the shortest distance B between the outer edge of the hole portion 25 is less than 0.9, the distance from the heat generating body 14 to the hole portion 25 is short , Resistance to thermal shock is insufficient, and cracks may occur.

[Sixth embodiment: B / (F - (E + C))]

It is preferable that the protective element 1 has B / (F - (E + C)) of 0.30 or more. That is to say, the distance (F - (E + C)) from the third side edge 10c of the insulating substrate 10 to the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10 It is preferable that the shortest distance B between the end on the side of the third side edge 10c and the outer edge of the hole 25 is 0.30 or more.

The distance F from the third side edge 10c represents the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10 and the distance B represents the distance 25) to the end of the heating element 14. Therefore, B / (F - (E + C)) defines the positional relationship between the center position of the insulating substrate 10 and the end portion of the heating element 14 on the side of the third side edge 10c.

The distance (F - (E + C)) from the third side edge 10c of the insulating substrate 10 to the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10 The shortest distance B between the end on the third side edge 10c side of the insulating substrate 14 and the outer edge of the hole 25 is 0.30 or more, It is possible to secure a length having resistance to the thermal impact of the heat generating element 14 in the region reaching the hole 25 where cracks tend to occur in the region on the side of the hole 10c, Can be prevented.

On the other hand, the distance (F - (E + C)) from the third side edge 10c of the insulating substrate 10 to the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10 When the shortest distance B between the edge of the third side edge 10c of the insulating substrate 10 and the edge of the hole 25 is less than 0.30, The distance between the heat generating element 14 and the hole portion 25 is short and resistance to thermal shock is insufficient and cracks may occur.

In addition to (F - (E + C)), the distance from the third side edge 10c of the insulating substrate 10 to the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10, (A + D) or (F / 2).

[Seventh Form: {B + (D + E) / 2} / {(B + C + D + E) / 2}

The protective element 1 is located at a distance {(B + C + D + E) / 2} half the length from the outer edge of the hole 25 to the fourth side edge 10d of the insulating substrate 10 (B + (D + E) / 2} / {(B + C + D) / 2} of the distance from the outer edge of the hole portion 25 to the center of the heating element 14, D + E) / 2} is 0.99 or more.

The distance {(B + C + D + E) / 2} of half the length from the outer edge of the hole portion 25 to the fourth side edge 10d of the insulating substrate 10 is the distance (B + (D + E) / 2) from the outer edge of the hole 25 to the center of the heat generating element 14 is obtained by calculating the ratio of the distance from the outer edge of the hole 25 to the center of the exothermic body 14 And defines the position of the heat generating center in the heat exchanger. The heat generating element 14 is formed so that {B + (D + E) / 2} / {(B + C + D + E) / 2} Substantially coincides with the center of the substrate 10 or deviates toward the fourth side edge 10d side. Therefore, it is possible to secure a length having resistance to the thermal impact of the heat generating element 14 in the region from the heat generating center of the heat generating element 14 to the hole portion 25, and the occurrence of the crack toward the hole portion 25 can be suppressed .

On the other hand, the ratio of the length ({B + C + D + E) / 2} of half the length from the outer edge of the hole 25 to the fourth side edge 10d of the insulating substrate 10 The ratio of the distance B + (D + E) / 2) from the outer edge to the center of the heating element 14 is less than 0.99, the heat generating center of the heating element 14 is substantially shifted from the center of the insulating substrate toward the third side edge 10c It is not possible to secure a length having resistance to the thermal impact of the heating element 14 in the area from the heating element 14 to the hole 25 and there is a fear that a crack toward the hole 25 is generated have.

[Circuit board]

Next, the circuit board 2 on which the protection element 1 is mounted will be described. As the circuit board 2, a known insulating substrate such as a rigid substrate such as a glass epoxy substrate, a glass substrate, or a ceramic substrate, or a flexible substrate is used. 2, the circuit board 2 has a mounting portion in which the protection element 1 is surface-mounted by a reflow or the like, and the back surface of the insulating substrate 10 of the protection element 1 12a, and 18b formed on the external connection electrodes 10a, 10f. An element such as an FET that energizes the heat generating element 14 of the protection element 1 is mounted on the circuit board 2. [

[How to use circuit module]

Next, a method of using the circuit module 3 in which the protection element 1 and the protection element 1 are surface-mounted on the circuit board 2 will be described. As shown in Fig. 10, the circuit module 3 is used, for example, as a circuit in a battery pack of a lithium ion secondary battery.

For example, the protection element 1 is mounted and used in a battery pack 50 having a battery stack 55 consisting of battery cells 51 to 54 of a total of four lithium ion secondary batteries.

The battery pack 50 includes a battery stack 55, a charge / discharge control circuit 60 for controlling charge and discharge of the battery stack 55, A detection circuit 56 for detecting the voltage of each of the battery cells 51 to 54 and a current control device 52 for controlling the operation of the protection device 1 in accordance with the detection result of the detection circuit 56. [ (57).

The battery stacks 55 are connected in series to battery cells 51 to 54 that require control to protect them from overcharging and overdischarging and are connected to positive terminal 50a and negative terminal 50b And is charged with a charging voltage from the charging device 65. The charging device 65 is connected to the charging device 65, The electronic device can be operated by connecting the positive electrode terminal 50a and the negative electrode terminal 50b of the battery pack 50 charged by the charging device 65 to the electronic device operated by the battery.

The charge and discharge control circuit 60 includes two current control elements 61 and 62 connected in series to the current path from the battery stack 55 to the charging device 65, And a control unit 63 for controlling the operation. The current control elements 61 and 62 are constituted by, for example, a field effect transistor (hereinafter referred to as FET) and control the gate voltage by the control part 63 to charge the current path of the battery stack 55 Direction and / or the discharging direction. The control unit 63 operates in response to the supply of power from the charging device 65 so that the current path is shut off when the battery stack 55 is overdischarged or overcharged in accordance with the detection result of the detection circuit 56, And controls the operation of the current control elements 61 and 62.

The protection element 1 is connected, for example, on the charging / discharging current path between the battery stack 55 and the charging / discharging control circuit 60, and its operation is controlled by the current control element 57.

The detection circuit 56 is connected to each of the battery cells 51 to 54 to detect the voltage value of each of the battery cells 51 to 54 and supplies the respective voltage values to the control section 63 of the charge / . The detection circuit 56 outputs a control signal for controlling the current control element 57 when any one of the battery cells 51 to 54 becomes an overcharge voltage or an overdischarge voltage.

The current control element 57 is constituted by, for example, an FET and the voltage value of the battery cells 51 to 54 exceeds the predetermined over discharge or overcharge state by the detection signal outputted from the detection circuit 56 The protection element 1 is operated to control the charge / discharge current path of the battery stack 55 to be cut off regardless of the switch operation of the current control elements 61 and 62. [

In the battery pack 50 constructed as described above, the configuration of the protection element 1 will be described in detail.

First, the protection device 1 to which the present invention is applied has a circuit configuration as shown in Fig. That is, the protection element 1 has a heating element 13, which is connected in series via a heating element lead-out electrode 16, and a heating element 13 for melting the usable conductor 13 by heating via a connection point between the usable conductors 13, (14). In the protection element 1, for example, the usable conductor 13 is connected in series on the charging / discharging current path, and the heating element 14 is connected to the current control element 57. The first electrode 11 of the protection element 1 is connected to the open end of the battery stack 55 via the external connection electrode 11a and the second electrode 12 is connected to the open end of the battery stack 55 via the external connection electrode 12a And is connected to the open end of the battery pack 50 on the positive electrode terminal 50a side. The heating element 14 is connected to the usable conductor 13 through the heating element lead-out electrode 16 to be connected to the charging and discharging current path of the battery pack 50. The first heating element electrode 18 and the external connection And is connected to the current control element 57 via the electrode 18b.

In such a battery pack 50, when the heating element 14 of the protection element 1 is energized and heated, the usable conductor 13 is melted and attracted onto the heating element lead-out electrode 16 by its wettability . As a result, the protective element 1 can reliably cut off the current path by melting the usable conductor 13. In addition, since the feeding path to the heating element 14 is also cut off by the melting of the usable conductor 13, the heating of the heating element 14 is also stopped.

In the battery pack 50, when the unexpected large current exceeding the rating of the protection element 1 flows on the charging / discharging path, the usable conductor 13 is fused by self heating (juxtaposition) .

As described above, since each constituent part constituting the protection element 1 such as the heating element 14 and the hole part 25 is suitably arranged in the protection element 1, the electric current of the heating element 14 It is possible to prevent cracks from being generated toward the hole portion 25 due to thermal shock at the time of heat generation and to transfer the heat generated by the heating element 14 to the usable conductor 13 efficiently. Therefore, the protective element 1 can obtain a desired heating value at the time of heat generation of the heating element 14, and can stably maintain the melting characteristic of the usable conductor 13.

Further, the protection element 1 to which the present technology is applied is not limited to the case where it is used for a battery pack of a lithium ion secondary battery, and may be used for various applications requiring interruption of an electric current path such as abnormal overheating of an IC Of course it is applicable.

Example

Next, an embodiment of the present technology will be described. In this embodiment, samples of Examples 1 to 3 and Comparative Examples 1 to 5, in which the dimensions and arrangement of the respective portions A to H of the above-described protective element 1 were changed, and the samples of the heating elements (electric power: 33 W) And it was verified whether cracks were generated at the time of heat generation. The crack was judged as "present" when any one of the insulating substrate and the heating element occurred.

A protective element related to each sample is a rectangular ceramic substrate (length F: 9.5 mm, width H: 5.0 mm) as the insulating substrate 10, The first and second heating element electrodes 18 and 19 are formed on the four side edges 10c and 10d and only the first heating element electrode 18 formed on the third side edge 10c side is formed as the hole 25 And the heating-element lead-out electrode 16 was connected to the second heating-element electrode 19 formed on the side of the fourth side edge 10d to form an asymmetric type.

The dimensions related to the samples of each of the examples and comparative examples are shown in Table 1, and the numerical values in the first to seventh embodiments and the occurrence of cracks are shown in Table 2.

[First Mode: About B / (D + E)]

In Examples 1 to 3, the end portion on the third side edge 10c side of the heating element 14 and the hole portion 25 formed in the first heating element electrode 18 with respect to the length (D + E) of the heating element 14, (B / (D + E)) of the shortest distance B of the outermost edge of the heat generating element 14 was 0.20 or more, the resistance against the heat generation amount of the heat generating element 14 was increased and no crack toward the hole portion 25 occurred.

In Comparative Examples 1 to 5, the distance B / (D + E)) is less than 0.20 and the distance from the heating element 14 to the hole portion 25 is shorter than the length (D + E) of the heating element 14, Insufficient heat shock resistance and cracking occurred.

[Second Embodiment: About B / G]

In Embodiments 1 to 3, the shortest distance between the end on the third side edge 10c side of the heating element 14 and the outer edge of the hole portion 25 with respect to the width G of the heating element 14 formed in a substantially rectangular shape B) of 1.0 or more and resistance to the heat generation of the heating element 14 is provided, cracks toward the hole portion 25 did not occur.

In Comparative Examples 1 to 5, the ratio of (B / G) was less than 1.0 and the distance from the heating element 14 to the hole portion 25 was shorter than the width G of the heating element 14, And a crack occurred.

[Third Mode: B / (G / (D + E))]

In Examples 1 to 3, the ratio of the aspect ratio (G / (D + E)) of the width (G) and the length (D + E) of the heating element 14 to the third side edge 10c side (G) of the heating element 14 and the length (B) of the heating element 14 in the insulating substrate 10 of the predetermined size (9.5 x 5.0 mm) and the shortest distance B of the edge of the hole 25 (B) from the heating element 14 to the hole 25 so as to have resistance to the heating amount of the heating element 14 with respect to the aspect ratio (G / (D + E) of the heating element 14 + It is possible to prevent the occurrence of a crack toward the hole portion 25. [

On the other hand, in the comparative examples 1 to 5, in comparison with the length (D + E) of the heating element 14 and the width G of the heating element 14, B / (G / (D + E) The distance between the hole 14 and the hole 25 was short, and resistance to thermal shock was insufficient, and a crack occurred.

[Fourth Embodiment: About B / (B + D + E + C)] [

The end portions on the side of the third side edge 10c of the heating element 14 with respect to the distance B + D + E + C from the outer edge of the hole portion 25 to the fourth side edge, The ratio of the shortest distance B of the outer edge of the heating element 14 to the length of the third side edge 10c of the heating element 14 with respect to the length of the substantially insulating substrate 10 subjected to the thermal impact of the heating element 14 The end portion and the shortest distance B of the outer edge of the hole portion 25 are large so that resistance against the heat generation amount of the heat generating element 14 is provided and cracks toward the hole portion 25 are not generated.

On the other hand, in the comparative examples 1 to 5, the heating element 14 at the length (B + D + E + C) of the insulating substrate 10 with B / (B + D + E + The shortest distance B between the end on the side of the third side edge 10c and the outer edge of the hole 25 is short and resistance to thermal shock is insufficient and a crack is generated.

[Fifth Embodiment: About B / C]

In Embodiments 1 to 3, the shortest distance C (4 mm) between the fourth side edge 10d and the end of the fourth side edge 10d side of the heat generating element 14 in the insulating substrate 10 of a predetermined size (9.5 x 5.0 mm) The ratio of the end of the heating body 14 on the side of the third side edge 10c to the shortest distance B of the outer edge of the hole 25 to the heating element 14 is 0.9 or more and the heating element 14 is on the side of the fourth side edge 10d The cracks toward the hole portion 25 did not occur because the resistance to the thermal shock of the region reaching the hole portion 25 where the crack easily occurs is improved.

On the other hand, in Comparative Examples 1 to 5, B / C was less than 0.9, the shortest distance B between the edge of the heating element 14 on the third side edge 10c side and the outer edge of the hole portion 25 was short, , And cracks were generated.

[Sixth embodiment: B / (F - (E + C))]

In the first to third embodiments, the distance F - (E + C) between the third side edge 10c of the insulating substrate 10 and the center position between the third and fourth side edges 10c and 10d of the insulating substrate 10 (B) between the end of the heating element 14 on the side of the third side edge 10c and the outer edge of the hole 25 is 0.30 or more and the third side edge A crack extending toward the hole 25 is secured in a region extending to the hole 25 in which cracks tend to occur in the region on the side of the hole 25, Did not occur.

On the other hand, in Comparative Examples 1 to 5, the ratio of B / (F - (E + C)) was less than 0.30, The shortest distance B between the end on the side of the third side edge 10c and the outer edge of the hole 25 was short and resistance to thermal shock was insufficient and cracks were generated.

[Brief Description of Drawings] Fig. 1 is a graph showing the relationship between the ratio (B + C + D + E) / (B + (D + E) / 2)

In the first to third embodiments, a hole for a half distance {(B + C + D + E) / 2} of the length from the outer edge of the hole 25 to the fourth side edge 10d of the insulating substrate 10 B + (D + E) / 2} / {(B + C + D + E) / 2} of the distance from the outer edge of the portion 25 to the center of the heating element 14, E) / 2} is 0.99 or more and the center of exotherm of the exothermic body 14 is substantially coincident with the center of the insulating substrate 10 or the side of the fourth side edge 10d. It is possible to secure a length having resistance to the thermal impact of the heating element 14 in the area from the opening 25 to the hole 25,

On the other hand, in Comparative Examples 1 to 5, since the exothermic center of the exothermic body 14 is less than 0.99 when {B + (D + E) / 2} / {(B + C + D + E) / 2} It is not possible to secure a length having resistance to the thermal impact of the heating element 14 in the region from the heating element 14 to the hole 25, (25).

1: Protection element
2: circuit board
3: Circuit module
10: Insulated substrate
11: first electrode
12: Second electrode
13: Available conductor
14: Heating element
15: Insulation member
16: Heating element extraction electrode
17: Flux
18: first heating element electrode
19: Second heating element electrode
20: cover member
21: Side
22:
25:
26:
27: Protection element
50: Battery pack
51 to 54: Battery cell
55: Battery stack
56: Detection circuit
57: Current control element
60: charge / discharge control circuit
61: current control element
62: Current control element
63:
65: Charging device

Claims (20)

An insulating substrate,
A heating element formed between a pair of side edges opposite to each other of the insulating substrate,
A first heating element electrode formed on one side of the pair of side edges of the insulating substrate and electrically connected to the heating element,
A second heating element electrode formed on the other side edge of the pair of side edges and electrically connected to the heating element,
And a usable conductor fused by the heat generated by the heating element to cut off the current path,
Wherein a center of the heating element is biased from a middle position of a distance from one side edge of the insulating substrate to the other side edge of the insulating substrate toward the other side edge. The method according to claim 1,
B / (D + E) is 0.20 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element The method according to claim 1,
B / G is 1.0 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
G: Width of the heating element formed in a substantially rectangular shape The method according to claim 1,
B / (G / (D + E)) of 6.0 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element
G: Width of the heating element formed in a substantially rectangular shape The method according to claim 1,
B / (B + D + E + C) is 0.15 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element The method according to claim 1,
B / C is 0.9 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element The method according to claim 1,
B / (F - (E + C)) is not less than 0.30.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element
F: distance between the one side and the other side edge of the insulating substrate The method according to claim 1,
(B + (D + E) / 2} / {(B + C + D + E) / 2} is 0.99 or more.
B: the shortest distance between the one end side edge of the heating element and the outer edge of the hole formed in the first heating element electrode, and when there are a plurality of the hole portions, the one end side edge of the heating element The shortest distance of the outer edge of the hole portion located on the heating element side
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element An insulating substrate,
A heating element formed between a pair of side edges opposite to each other of the insulating substrate,
A first heating element electrode formed on one side of the pair of side edges of the insulating substrate and electrically connected to the heating element and having a first hole portion;
A second heating element electrode formed on the other side edge of the pair of side edges and electrically connected to the heating element and having a second hole portion;
And a usable conductor fused by the heat generated by the heating element to cut off the current path,
The center of the heating element is formed so as to be shifted from the middle position of the distance from the side edge of the one side of the insulating substrate to the side edge of the other side of the insulating substrate to the side edge side of the first and second heating electrode, Protection device. 10. The method of claim 9,
B / (D + E) is 0.20 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element 10. The method of claim 9,
B / G is 1.0 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
G: Width of the heating element formed in a substantially rectangular shape 10. The method of claim 9,
B / (G / (D + E)) of 6.0 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element
G: Width of the heating element formed in a substantially rectangular shape 10. The method of claim 9,
B / (B + D + E + C) is 0.15 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element 10. The method of claim 9,
B / C is 0.9 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element 10. The method of claim 9,
B / (F - (E + C)) is not less than 0.30.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element
F: distance between the one side and the other side edge of the insulating substrate 10. The method of claim 9,
(B + (D + E) / 2} / {(B + C + D + E) / 2} is 0.99 or more.
B: the end of the side edge of the first and second heating element electrodes where the heating element electrode having a small heat capacity is formed and the end of the outer edge of the heating element electrode of the first and second heating element electrodes, And a plurality of the hole portions are provided on the side of the side edge where the heating element electrode having a small heat capacity is formed among the first and second heating element electrodes of the heating element, Street
C: the shortest distance between the other side edge of the insulating substrate and the end of the other side edge of the heating element
D: a distance between a center line parallel to the side edges of the one and the other side edge passing through the central portion between the one side edge and the other side edge of the insulating substrate and the one edge side edge of the heating element
E: a distance between a center line parallel to the one side and the other side edge of the insulating substrate passing through the central portion between the one side edge and the other side edge and a side edge of the other side edge of the heating element 17. The method according to any one of claims 1 to 16,
Wherein the center of the usable conductor is mounted on the heat generating center of the heating element in a superimposed manner. 17. The method according to any one of claims 1 to 16,
And the heating-element lead electrode connected to the usable conductor is connected to the second heating-element electrode. 19. The method of claim 18,
And first and second electrodes formed on the surface of the insulating substrate so as to face each other with the heating-element lead-out electrode interposed therebetween,
Wherein the heating-element lead-out electrode is formed on a current path between the first and second electrodes,
Wherein the usable conductor is laminated from the heating element lead-out electrode to the first and second electrodes, and is fused by heat generation of the heating element to cut off the current path between the first electrode and the second electrode. 17. The method according to any one of claims 1 to 16,
Wherein the hole portion is a cast and / or through hole reaching the back surface of the insulating substrate,
Wherein the first heating element electrode is connected to an external connection electrode formed on a back surface of the insulating substrate through the hole portion.

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