CN110957188A

CN110957188A - Disconnecting element and disconnecting element circuit

Info

Publication number: CN110957188A
Application number: CN201911368547.6A
Authority: CN
Inventors: 米田吉弘
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2013-08-28
Filing date: 2014-08-27
Publication date: 2020-04-03
Also published as: CN105493219A; TW201523680A; KR102275927B1; JP6184805B2; KR20160046762A; JP2015046316A; WO2015030020A1; TWI629702B

Abstract

The invention relates to a disconnecting element and a disconnecting element circuit. Provided is a cutting element which can supply sufficient power to a heating element to fuse a fusible conductor even when the cutting element is incorporated in a weak current path. The cutting element comprises: an insulating substrate (10); first and second electrodes (11, 12) forming a first circuit (2); third to fifth electrodes (13 to 15) constituting a second circuit (3); a first fusible conductor (17) mounted between the first and second electrodes (11, 12); a heating element (18) connected between the third and fourth electrodes (13, 14); and a second fusible conductor (19) mounted between the fourth and fifth electrodes (14, 15); the second fusible conductor (19) is fused after the first fusible conductor (17) is fused by the heat of the heating element (18).

Description

Disconnecting element and disconnecting element circuit

The present application is a divisional application based on the inventions of application No. 201480047053.7, application date 2014 8/27, ediri co-located corp, entitled "cutting element and cutting element circuit".

Technical Field

The present invention relates to a disconnecting element and a disconnecting element circuit that electrically and physically disconnect a power supply line and a signal line to ensure safety. The present application claims priority based on japanese patent application No. 2013-177058, filed in japan on 28.8.2013, and is incorporated herein by reference.

Background

A secondary battery that can be repeatedly used by charging is often manufactured as a battery pack and provided to a user. In particular, in order to secure safety of users and electronic devices, lithium ion secondary batteries having a high weight energy density generally include a plurality of protection circuits such as overcharge protection and overdischarge protection in a battery pack, and have a function of cutting off an output of the battery pack in a predetermined case.

In such a cutoff element, overcharge protection or overdischarge protection of the battery pack may be performed by turning ON/OFF an output using an FET switch incorporated in the battery pack. However, even when the FET switch is short-circuited for some reason or when a large current flows instantaneously due to application of a lightning surge or the like or when an abnormal voltage which is excessively large and abnormally decreased or conversely outputted due to the life of the battery cell, the battery pack and the electronic device must be protected from an accident such as ignition. Therefore, in order to safely cut the output of the battery cell in any abnormal state that can be assumed as described above, a cutting element including a fuse element having a function of cutting a current path in response to a signal from the outside is used.

As shown in fig. 17, as a cutoff element 80 suitable for a protection circuit of such a lithium ion secondary battery or the like, the following elements have been proposed: the fusible conductor 83 is bridged between the first and

second electrodes

81 and 82 connected to the current path to form a part of the current path, and the fusible conductor 83 on the current path is fused by self-heating by an overcurrent or a heating element 84 provided inside the cut element 80.

Specifically, the cutting element 80 includes: an insulating substrate 85; a heating element 84 laminated on the insulating substrate 85 and covered with an insulating member 86; first and

second electrodes

81 and 82 formed at both ends of an insulating substrate 85; a heating element-drawing electrode 88 laminated on the insulating member 86 so as to overlap the heating element 84, and a fusible conductor 83 having both ends connected to the first and

second electrodes

81 and 82, respectively, and a central portion connected to the heating element-drawing electrode 88.

Fig. 18 is a circuit diagram of the cut-off element 80. That is, the cutting element 80 has a circuit configuration including the soluble conductor 83 connected in series via the heating element extraction electrode 88, and the heating element 84 that generates heat and melts the soluble conductor 83 by passing current through the connection point of the soluble conductor 83. In the cutting element 80, for example, the soluble conductor 83 is connected in series to the charge/discharge current path, and the heating element 84 is connected to the current control element 87. The current control element 87 is composed of, for example, a field effect transistor (hereinafter, referred to as FET), and controls to cause a current to flow through the heating element 84 via the soluble conductor 83 when the lithium ion secondary battery exhibits an abnormal voltage.

Thus, the cutting element 80 cuts the current path between the first and

second electrodes

81 and 82 by fusing the fusible conductor 83 on the current path by heat generation of the heating element 84 and collecting the fused conductor on the heating element extraction electrode 88, thereby electrically and physically cutting the charge/discharge path of the battery module.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-003665;

patent document 2: japanese patent laid-open publication No. 2004-185960;

patent document 3: japanese patent laid-open No. 2012 and 003878.

Disclosure of Invention

Technical problem to be solved by the invention

Here, in the cutting element 80 shown in fig. 17 and 18, although electric power for generating heat of the heating element 84 is supplied through the soluble conductor 83, since the current path passing through the first electrode 81 to the soluble conductor 83 to the second electrode 82 is a charge/discharge path of the battery, sufficient heat for fusing the soluble conductor 83 can be obtained on the heating element 84 even at the time of energization of the heating element 84.

However, when the cutting element 80 is used for a signal line through which a current weaker than that of the power supply line flows, electric power that can obtain a sufficient amount of heat generation to fuse the fusible conductor 83 cannot be supplied to the heating element 84, and the use of the cutting element 80 is limited to the large-current use.

Further, the current control element 87 that switches the current path to the heating element 84 side is also required to increase the rating in the same manner as the current rating increases. In addition, a high-rated current control element is generally expensive, and is disadvantageous in terms of cost.

Therefore, an object of the present invention is to provide a cutting element and a cutting element circuit, which can supply sufficient power to a heating element to fuse a soluble conductor even when the cutting element is incorporated in a weak current path, and which can be used for all purposes.

Means for solving the problems

In order to solve the above problem, a cutting element according to the present invention includes: an insulating substrate; first and second electrodes formed on the insulating substrate to constitute a first circuit; third to fifth electrodes formed on the insulating substrate to constitute a second circuit; a first fusible conductor carried across the first and second electrodes; a heating element connected between the third and fourth electrodes; and a second fusible conductor that is bridged between the fourth and fifth electrodes, and fuses the second fusible conductor after the first fusible conductor is fused by heat generated by the heating element by passing current between the third to fifth electrodes.

Further, the blocking element circuit of the present invention includes: a first circuit having a first fusible conductor; and a second circuit which is formed independently of the first circuit, has a heating element and a second fusible conductor connected to one end of the heating element, and fuses the first fusible conductor to cut the first circuit by heat generated by the heating element when a current is caused to flow through the second circuit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since the first circuit is electrically independent from the second circuit for cutting off the first circuit, it is possible to supply the heat generating body with electric power capable of obtaining a sufficient amount of heat generation to fuse the first fusible conductor, regardless of the type of the external circuit in which the first circuit is incorporated. Therefore, the present invention can be applied to a digital signal circuit or the like in which a weak current flows, as an external circuit in which the first circuit is incorporated.

Drawings

FIG. 1 is a drawing showing a cutting element to which the present invention is applied, (A) is a plan view, (B) is a sectional view taken along line A-A', and (C) is a sectional view.

Fig. 2 is a circuit diagram showing a cutting element to which the present invention is applied.

Fig. 3 is a circuit diagram showing a circuit of a cutting element to which the present invention is applied.

Fig. 4 is a diagram showing a state after the first fusible conductor to which the cutting element of the present invention is applied is fused, (a) is a plan view, (B) is a circuit diagram, and (C) is a sectional view.

Fig. 5 is a diagram showing a state after the second fusible conductor to which the cutting element of the present invention is applied is fused, (a) is a plan view, (B) is a circuit diagram, and (C) is a sectional view.

Fig. 6 is a diagram showing an application example to which the cutting element of the present invention is applied, where (a) shows before the first and second fusible conductors are fused, and (B) shows after the fusing.

FIG. 7 is a view showing another cutting member to which the present invention is applied, wherein (A) is a plan view, and (B) is a sectional view taken along line A-A'.

FIG. 8 is a view showing another cutting member to which the present invention is applied, wherein (A) is a plan view, and (B) is a sectional view taken along line A-A'.

FIG. 9 is a view showing another cutting member to which the present invention is applied, wherein (A) is a plan view, and (B) is a sectional view taken along line A-A'.

FIG. 10 is a view showing another cutting member to which the present invention is applied, wherein (A) is a plan view, and (B) is a sectional view taken along line A-A'.

Fig. 11 is a perspective view showing a fusible conductor having a high-melting-point metal layer and a low-melting-point metal layer and having a covering structure, where (a) shows a structure in which the high-melting-point metal layer is an inner layer and is covered with the low-melting-point metal layer, and (B) shows a structure in which the low-melting-point metal layer is an inner layer and is covered with the high-melting-point metal layer.

Fig. 12 is a perspective view showing a fusible conductor having a laminated structure of a high melting point metal layer and a low melting point metal layer, where (a) shows an upper and lower 2-layer structure, and (B) shows a 3-layer structure of an inner layer and an outer layer.

Fig. 13 is a cross-sectional view showing a fusible conductor having a multilayer structure including a high-melting-point metal layer and a low-melting-point metal layer.

Fig. 14 is a plan view showing a fusible conductor in which linear openings are formed in the surface of a high-melting-point metal layer and a low-melting-point metal layer is exposed, (a) shows openings formed along the longitudinal direction, and (B) shows openings formed along the width direction.

Fig. 15 is a plan view showing a fusible conductor in which a circular opening is formed in the surface of a high melting point metal layer and a low melting point metal layer is exposed.

Fig. 16 is a plan view showing a fusible conductor in which a circular opening is formed in a high-melting-point metal layer and a low-melting-point metal is filled therein.

Fig. 17 is a plan view showing a cutting element according to a reference example of the present invention.

Fig. 18 is a circuit diagram of a disconnecting element according to a reference example of the present invention.

Detailed Description

Hereinafter, a cutting element and a cutting element circuit to which the present invention is applied will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications may be made without departing from the spirit of the present invention. In addition, since the drawings are schematic, the proportions of the respective dimensions and the like may be different from those in reality. The specific dimensions and the like must be determined in consideration of the following description. It is needless to say that the drawings include portions having different dimensional relationships and ratios from each other.

[ first mode ]

As shown in fig. 1, a cutting element 1 to which the present invention is applied includes: an insulating substrate 10; a first electrode 11 and a second electrode 12 formed on the insulating substrate 10 to constitute a first circuit 2; a third electrode 13, a fourth electrode 14, and a fifth electrode 15 formed on the insulating substrate 10 to constitute a second circuit 3; a first fusible conductor 17 (fuse) bridged between the first and

second electrodes

11, 12; a heating element 18 connected between the third and

fourth electrodes

13 and 14; and a second fusible conductor (fuse) 19 bridged between the fourth and

fifth electrodes

14, 15. Fig. 1(a) is a plan view of the cutting element 1, fig. 1(B) is a sectional view a-a', and (C) is a sectional view.

The insulating substrate 10 is formed of a material having insulating properties, such as alumina, glass ceramic, mullite, or zirconia. In addition, although a material for a printed wiring board such as a glass epoxy board or a phenol board can be used, it is necessary to pay attention to the temperature at which the fuse is blown.

First and second electrodes: first Circuit

The first and

second electrodes

11, 12 are formed on the surface 10a of the insulating substrate 10, and are laminated on an insulating member 21 described later. In addition, the first and

second electrodes

11 and 12 are connected to external connection terminals formed on the rear surface 10b of the insulating substrate 10 through the through holes 20.

The first and

second electrodes

11 and 12 are electrically connected by mounting the first fusible conductor 17. Thus, the cutting element 1 constitutes the first circuit 2 including the first electrode 11 to the first soluble conductor 17 to the second electrode 12, and the first circuit 2 is incorporated in a part of a circuit formed on a circuit board on which the cutting element 1 is mounted.

The circuit in which the first circuit 2 is incorporated is a current line of an electronic device to which the interruption element 1 is attached, and can be applied to, for example, a charge/discharge circuit in a battery pack of a lithium ion secondary battery, a power supply circuit of various electronic devices, or all circuits required to physically interrupt a current path regardless of the intensity of a current, such as a digital signal circuit.

[ heating element ]

The heating element 18 is stacked on the surface 10a of the insulating substrate 10 and covered with an insulating member 21. The heating element 18 is a conductive member having a high resistance value and generating heat after being energized, and is formed of, for example, W, Mo, Ru, or the like. The insulating substrate 10 is formed by mixing a powder of an alloy, a composition, or a compound of these metals with a resin binder or the like to form a paste, patterning the paste on the insulating substrate 10 by screen printing, and then sintering the pattern. One end of the heating element 18 is connected to the third electrode 13, and the other end is connected to the fourth electrode 14.

The insulating member 21 is disposed so as to cover the heating element 18, and the first electrode 11, the second electrode 12, the fourth electrode 14, and the fifth electrode 15 are stacked so as to overlap the heating element 18 with the insulating member 21 interposed therebetween. As the insulating member 21, for example, glass can be used. In order to efficiently transfer the heat of the heating element 18 to the first fusible conductor 13, the cutting element 1 may be configured such that an insulating member is laminated between the heating element 18 and the insulating substrate 10, and the heating element 18 is provided inside the insulating member 21 formed on the surface of the insulating substrate 10.

[ third to fifth electrodes: second circuit

The third electrode 13 is formed on the surface 10a of the insulating substrate 10 and connected to one end of the heating element 18. The fourth electrode 14 is connected to the other end of the heating element 18 by being formed on the surface 10a of the insulating substrate 10, and is laminated on the insulating member 21. The fifth electrode 15 is formed on the surface 10a of the insulating substrate 10, and is laminated on the insulating member 21. The third electrode 13 and the fifth electrode 15 are connected to external connection terminals formed on the rear surface 10b of the insulating substrate 10 through the through holes 20.

The fourth and

fifth electrodes

14 and 15 are electrically connected by mounting the second fusible conductor 19 on the insulating member 21. Thus, the third to fifth electrodes 13 to 15 constitute a second circuit 3 electrically independent from the first circuit 2. The second circuit 3 is a circuit for heating and fusing the first fusible conductor 17 of the first circuit 2, and after the first circuit 2 is cut by fusing the first fusible conductor 17, the second fusible conductor 19 is fused to cut itself, and the power supply to the heating element 18 is stopped.

[ fusible conductor ]

Any metal that melts rapidly due to heat generated by the heating element 18 can be used for the first and second

fusible conductors

17 and 19, and a low melting point metal such as lead-free solder containing Sn as a main component can be preferably used.

The first and second

fusible conductors

17 and 19 may contain a low melting point metal and a high melting point metal. As the low melting point metal, solder such as lead-free solder is preferably used, and as the high melting point metal, Ag, Cu, an alloy containing these as a main component, or the like is preferably used. By containing the high melting point metal and the low melting point metal, even if the reflow temperature exceeds the melting temperature of the low melting point metal layer and the low melting point metal melts in the case of reflow mounting of the cutting element 1, the low melting point metal in the inner layer can be suppressed from flowing out to the outside, and the shape of the first and second

fusible conductors

17 and 19 can be maintained. In addition, even when the low-melting-point metal is melted at the time of fusing, the high-melting-point metal is melted (solder leaching), and thus the high-melting-point metal can be fused rapidly at a temperature equal to or lower than the melting point of the high-melting-point metal. The first to third fusible conductors 21 to 23 can be formed in various configurations as described later.

The first and second

fusible conductors

17 and 19 may be configured to have a low melting point metal layer as an inner layer and a high melting point metal layer as an outer layer. The first and second

fusible conductors

17 and 19 may be formed by forming a film of a high-melting metal on a low-melting metal foil by using a plating technique, or may be formed by using another known lamination technique or film formation technique. The first and second

fusible conductors

17 and 19 may be configured to have a high-melting-point metal layer as an inner layer and a low-melting-point metal layer as an outer layer, or may have a multilayer structure of 4 or more layers in which the low-melting-point metal layer and the high-melting-point metal layer are alternately stacked.

The first and second

fusible conductors

17 and 19 are connected to the first and

second electrodes

11 and 12 and the fourth and

fifth electrodes

14 and 15 by solder or the like. When the first circuit 2 is applied to a digital signal circuit, a silver plating layer having good high-frequency characteristics is preferably formed as the outer layer of the first fusible conductor 17. Thus, the first soluble conductor 17 can have a low resistance due to the surface effect to improve the high-frequency characteristics, and can also flow through the silver plating layer of the outer layer even when an instantaneous large current flows, thereby improving the pulse resistance to prevent the fusing due to the self-heating.

[ first melting of the first fusible conductor ]

Here, the cutting element 1 is formed such that the first fusible conductor 17 of the first circuit 2 is blown before the second fusible conductor 19 of the second circuit 3. This is because if the second fusible conductor 19 is blown before the first fusible conductor 17, the power supply to the heating body 18 is stopped, and the first fusible conductor 17 cannot be blown.

Therefore, the cutting element 1 is formed such that the first fusible conductor 17 is fused first after the heat generating element 18 generates heat. Specifically, the first fusible conductor 17 of the cutting element 1 is mounted closer to the heat generation center of the heating element 18 than the second fusible conductor 19.

Here, the heat generation center of the heat generating element 18 refers to a region having the highest temperature in the initial stage of heat generation in the heat distribution generated by the heat generating element 18. The heat generated by the heating element 18 is most dissipated from the insulating substrate 10, and the heat is diffused to the insulating substrate 10 when the insulating substrate 10 is formed of a ceramic material having excellent thermal shock resistance but high thermal conductivity. Therefore, at the initial stage of heat generation in which energization has already started, the heat generating element 18 is hottest at the center farthest from the outer edge in contact with the insulating substrate 10, and the heat is radiated toward the outer edge in contact with the insulating substrate 10, so that the temperature is hard to rise.

Therefore, in the cutting element 1, by mounting the first fusible conductor 17 at a position closer to the heat generation center of the highest temperature in the initial stage of heat generation of the heating element 18 than the second fusible conductor 19, heat can be transmitted to the first fusible conductor 17 earlier than the second fusible conductor 19, and the first fusible conductor 17 can be fused. Since the second fusible conductor 19 is heated more slowly than the first fusible conductor 17, the second fusible conductor 19 is blown after the first fusible conductor 17 is blown.

In addition, the cutting element 1 may be configured such that the first fusible conductor 17 is blown first by changing the shapes of the first and second

fusible conductors

17 and 19. For example, since the smaller the cross-sectional area of the first and second

fusible conductors

17 and 19, the easier the fusing, the first fusible conductor 17 can be fused before the second fusible conductor 19 by making the cross-sectional area of the first fusible conductor 17 smaller than the cross-sectional area of the second fusible conductor 19 in the cutting element 1.

In the cutting element 1, the first fusible conductor 17 may be formed to have a narrow width and a long length along the current path between the first and

second electrodes

11 and 12, and the second fusible conductor 19 may be formed to have a wide width and a short length along the current path between the fourth and

fifth electrodes

14 and 15. Thus, the first soluble conductor 17 is in a shape relatively easier to fuse than the second soluble conductor 19, and fuses earlier than the second soluble conductor 19 by heat generated by the heating element 18.

In the cutting element 1, the first fusible conductor 17 may be formed of a material having a lower melting point than the material of the second fusible conductor 19. Accordingly, the first soluble conductor 17 can be more easily fused than the second soluble conductor 19 by the heat generated by the heating element 18, and the first soluble conductor 17 can be reliably fused before the second soluble conductor 19.

In addition, in the cutting element 1, the difference in melting point may be generated by changing the layer structures of the first fusible conductor 17 and the second fusible conductor 19, so that the first fusible conductor 17 is more easily fused than the second fusible conductor 19, and the first fusible conductor 17 is fused before the second fusible conductor 19 by heat generation of the heating element 18.

[ others ]

Furthermore, the first and second

fusible conductors

17 and 19 are coated with a flux 22 in order to prevent oxidation of the first and second

fusible conductors

17 and 19 and to improve wettability when the first and second

fusible conductors

17 and 19 are melted.

In the cutting element 1, the insulating substrate 10 is covered with the covering member 23 to protect the inside thereof. The covering member 23 is formed of an insulating material such as thermoplastic, ceramic, or glass epoxy resin substrate, as in the insulating substrate 10.

[ Circuit Structure ]

Next, a circuit configuration of the cutting element 1 will be described. Fig. 2 shows a circuit diagram of the disconnecting element 1. Fig. 3 shows an example of a cutting element circuit 30 to which the cutting element 1 is applied. The cutting element 1 has a first circuit 2 in which a first electrode 11 and a second electrode 12 are connected by a first fusible conductor 17. The first circuit 2 is incorporated in various external circuits 31 such as a power supply circuit and a digital signal circuit by being connected in series to a current path of a circuit board on which the disconnecting element 1 is mounted.

The cutting element 1 further includes a second circuit 3 in which the heating element 18 and the second fusible conductor 19 are connected in series via the fourth electrode 14. The second circuit 3 is electrically independent from the first circuit 2 and can be thermally connected. One end of the heating element 18 is connected to the third electrode 13, and the other end is connected to the fourth electrode 14. In addition, the second fusible conductor 19 is bridged between the fourth electrode 14 and the fifth electrode 15. The third electrode 13 is connected to a current control element 25 that controls power supply to the second circuit 3 through an external connection terminal, and the fifth electrode 15 is connected to an external power supply 26 through an external connection terminal.

The current control element 25 is a switching element that controls power supply to the second circuit 3, and is connected to a detection circuit 27 that is formed of, for example, an FET and detects whether or not the first circuit 2 is to be electrically and physically disconnected. The detection circuit 27 is a circuit that detects a situation in which it is necessary to cut off various circuits incorporating the first circuit 2 of the disconnecting element 1, and activates the current control element 25 when there is a need to physically and irreversibly disconnect the current path from the outside by cutting off the first circuit 2, for example, when an abnormal voltage of a battery pack, a hacker or crack in a network communication device, or an authorized period of software expires.

Thus, the heating element 18 generates heat by supplying electric power from the external power supply 26 to the second circuit 3, and the first fusible conductor 17 is fused (fig. 4(a) (B) (C)). The molten conductor of the first fusible conductor 17 is drawn onto the first electrode 11 and the second electrode 12 having high wettability. Therefore, the first fusible conductor 17 can surely cut the first electric circuit 2. Further, since the first fusible conductor 17 is fused earlier than the second fusible conductor 19, the second circuit 3 can reliably supply power to the heating element 18 and generate heat until the first circuit 2 is cut.

The heating element 18 continues to generate heat even after the first fusible conductor 17 is fused, but the second fusible conductor 19 is also fused after the first fusible conductor 17, and the second circuit 3 is also cut (fig. 5(a), (B), and (C)). This also stops the power supply to the heating element 18.

According to the cutting element 1 and the cutting element circuit 30, the first circuit 2 incorporated in the external circuit 31 and the second circuit 3 for cutting off the first circuit 2 are electrically independent from each other, and therefore, electric power capable of obtaining a sufficient amount of heat generation to fuse the first fusible conductor 17 can be supplied to the heating element 18 regardless of the type of the external circuit 31. Therefore, the blocking element 1 and the blocking element circuit 30 can be applied to a digital signal circuit through which a weak current flows as the external circuit 31 for assembling the first circuit 2.

As shown in fig. 6(a), when the first circuit 2 is incorporated between the data server 33 and the internet line 34 for the purpose of information security and a hacking or cracking is detected by the detection circuit 27, the disconnecting element 1 and the disconnecting element circuit 30 can prevent information from flowing out by physically and irreversibly disconnecting the signal line from the internet line 34 by disconnecting the first circuit 2 as shown in fig. 6 (B).

In addition, the disconnecting element 1 and the disconnecting element circuit 30 can be applied to cancellation of physical authorization authentication of the device (device), and the function corresponding to the modification behavior of the device is stopped as a measure against pl (product availability).

Further, according to the cutting element 1 and the cutting element circuit 30, since the second circuit 3 is formed electrically independently of the first circuit 2, the current control element 25 for controlling the power supply to the heating element 18 can be selected in accordance with the rating of the heating element 18 regardless of the rating of the first circuit 2, and thus the manufacturing can be performed more inexpensively.

[ second mode ]

The cutting element may be formed on the back surface 10b of the insulating substrate 10 opposite to the surface 10a on which the first to fifth electrodes 11 to 15 are formed, as shown in fig. 7, in addition to forming the heating element 18 on the surface 10a on which the first to fifth electrodes 11 to 15 are formed of the insulating substrate 10 and overlapping the first and

second electrodes

11 and 12 and the fourth and

fifth electrodes

14 and 15. Fig. 7(a) is a plan view showing the cutting element 40 in which the heating element 18 is formed on the rear surface of the insulating substrate 10, and fig. 7(B) is a sectional view taken along line a-a'. The same components as those of the cutting element 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the cutting element 40, one ends of the third electrode 13 and the fourth electrode 14 are also formed on the rear surface 10b side of the insulating substrate 10. The other end of the fourth electrode 14 is formed on the surface 10a of the insulating substrate 10, and the second fusible conductor 19 is mounted between the fourth electrode 14 and the fifth electrode 15. One end and the other end of the fourth electrode 14 are connected through a through hole 20.

In the cutting element 40, the heating element 18 is formed on the rear surface 10b of the insulating substrate 10, whereby the front surface 10a of the insulating substrate 10 is made flat, and the first and

second electrodes

11 and 12, the other end side of the fourth electrode 14, and the fifth electrode 15 can be formed in a simple process. In this case, the insulating member 21 is formed on the heating element 18, so that the heating element 18 can be protected and the insulating property at the time of mounting the cutting element 1 can be secured.

In this case, it is preferable that the heating element 18 is overlapped with the first and

second electrodes

11 and 12, and the first fusible conductor 17 is disposed closer to the heating center of the heating element 18 than the second fusible conductor 19. Further, the heating element 18 may be overlapped with the fourth and

fifth electrodes

14 and 15, and the heat of the heating element 18 may be efficiently transmitted to the second fusible conductor 19.

[ third mode ]

As shown in fig. 8, the cutting element may be formed by forming the heating element 18 inside the insulating substrate 10. Fig. 8(a) is a plan view showing the cutting element 50 in which the heating element 18 is formed inside the insulating substrate 10, and fig. 8(B) is a sectional view taken along line a-a'. The same components as those of the cutting element 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the cutting element 50, for example, when the insulating substrate 10 is formed of a ceramic material, the heating element 18, the third electrode 13, and one end of the fourth electrode 14 are formed on the surface, and then the ceramic material is further laminated, whereby the insulating substrate 10 having the heating element 18 formed therein can be obtained. One end of each of the third electrode 13 and the fourth electrode 14 is connected to the other end of the front surface 10a or the back surface 10b of the insulating substrate 10 through the through hole 20.

In the cutting element 50, the heating element 18 is formed inside the insulating substrate 10, so that the surface 10a of the insulating substrate 10 can be made flat, and the first and

second electrodes

11 and 12, the other end side of the fourth electrode 14, and the fifth electrode 15 can be formed in a simple process. In the cutting element 50, since the heating element 18 is formed inside the insulating substrate 10, the insulating member 21 is not necessarily provided.

second electrodes

fifth electrodes

[ fourth mode ]

As shown in fig. 9, the cutting element 1 may be formed by arranging the heating element 18, the first and

second electrodes

11 and 12, and the fourth and

fifth electrodes

14 and 15 on the surface 10a of the insulating substrate 10. FIG. 9A is a plan view showing a cutting element 60 in which the heating element 18 is formed on the surface of the insulating substrate 10 in alignment with the first and

second electrodes

11, 12 and the fourth and

fifth electrodes

14, 15, and FIG. 9B is a sectional view A-A'. The same components as those of the cutting element 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the cutting element 60, the first fusible conductor 17 is preferably disposed closer to the heat generation center of the heating element 18 than the second fusible conductor 19. As shown in fig. 10(a) and (B), only the first and

second electrodes

11 and 12 may be stacked on the heating element 18 with the insulating member 21 interposed therebetween, and only the first soluble conductor 17 may be stacked on the heating element 18. Thus, the first soluble conductor 17 is arranged closer to the heating element 18 than the second soluble conductor 19 is, and can be fused earlier than the second soluble conductor 19.

[ first and second fusible conductors ]

As described above, any or all of the first and second

fusible conductors

17 and 19 may also contain a low melting point metal and a high melting point metal. In this case, as shown in fig. 11(a), the first and second

fusible conductors

17 and 19 may be made of a high-melting-point metal layer 40 made of Ag, Cu, an alloy containing these as a main component, or the like as an inner layer, and a low-melting-point metal layer 41 made of lead-free solder containing Sn as a main component as an outer layer. In this case, the first and second

fusible conductors

17 and 19 may be configured such that the entire surface of the high melting point metal layer 40 is covered with the low melting point metal layer 41, or may be configured such that the entire surface is covered except for a pair of side surfaces facing each other. The structure covered with the high-melting-point metal layer 40 and the low-melting-point metal layer 41 can be formed by using a known film formation technique such as electroplating.

As shown in fig. 11(B), the first and second

fusible conductors

17 and 19 may be fusible conductors each having a low-melting-point metal layer 41 as an inner layer and a high-melting-point metal layer 40 as an outer layer. In this case, the first and second

fusible conductors

17 and 19 may be configured such that the entire surface of the low melting point metal layer 41 is covered with the high melting point metal layer 40, or may be configured such that the entire surface is covered except for a pair of side surfaces facing each other.

As shown in fig. 12, the first and second

fusible conductors

17 and 19 may have a laminated structure in which a high melting point metal layer 40 and a low melting point metal layer 41 are laminated.

In this case, as shown in fig. 12(a), the first and second

fusible conductors

17 and 19 have a 2-layer structure including a lower layer mounted on the first and

second electrodes

11 and 12 or the fourth and

fifth electrodes

14 and 15 and an upper layer stacked on the lower layer, and the low melting point metal layer 41 may be stacked as the upper layer on the high melting point metal layer 40 as the lower layer, or conversely, the high melting point metal layer 40 may be stacked as the upper layer on the low melting point metal layer 41 as the lower layer. Alternatively, as shown in fig. 12(B), the first and second

soluble conductors

17 and 19 may have a 3-layer structure including an inner layer and outer layers laminated on upper and lower surfaces of the inner layer, the low melting point metal layer 41 as the outer layer may be laminated on upper and lower surfaces of the high melting point metal layer 40 as the inner layer, and conversely, the high melting point metal layer 40 as the outer layer may be laminated on upper and lower surfaces of the low melting point metal layer 41 as the inner layer.

As shown in fig. 13, the first and second

fusible conductors

17 and 19 may have a multilayer structure of 4 or more layers in which the high melting point metal layer 40 and the low melting point metal layer 41 are alternately stacked. In this case, the first and second

fusible conductors

17 and 19 may be structured such that the entire surface or surfaces other than a pair of side surfaces facing each other are covered with the metal layer constituting the outermost layer.

The first and second

fusible conductors

17 and 19 may be formed by partially laminating the high-melting-point metal layer 40 in a stripe shape on the surface of the low-melting-point metal layer 41 constituting the inner layer. Fig. 14 is a plan view of the first and second

fusible conductors

17, 19.

In the first and second

fusible conductors

17 and 19 shown in fig. 14(a), a plurality of linear high-melting-point metal layers 40 are formed on the surface of the low-melting-point metal layer 41 in the longitudinal direction at predetermined intervals in the width direction, whereby linear openings 42 are formed along the longitudinal direction, and the low-melting-point metal layer 41 is exposed from the openings 42. The first and second

fusible conductors

17 and 19 are exposed from the opening 42 through the low melting point metal layer 41, and the contact area between the low melting point metal and the high melting point metal after melting is increased, so that the erosion action of the high melting point metal layer 40 is further promoted, and the fusing property can be improved. The opening 42 can be formed by, for example, performing partial plating of the metal constituting the high melting point metal layer 40 on the low melting point metal layer 41.

As shown in fig. 14(B), the first and second

fusible conductors

17 and 19 may have linear openings 42 formed along the width direction by forming a plurality of linear high-melting-point metal layers 40 on the surface of the low-melting-point metal layer 41 at predetermined intervals in the longitudinal direction and in the width direction.

As shown in fig. 15, the first and second

soluble conductors

17 and 19 may be formed by forming a high-melting-point metal layer 40 on the surface of a low-melting-point metal layer 41, forming a circular opening 43 on the entire surface of the high-melting-point metal layer 40, and exposing the low-melting-point metal layer 41 through the opening 43. The opening 43 can be formed by, for example, performing partial plating of the metal constituting the high-melting-point metal layer 40 on the low-melting-point metal layer 41.

The first and second

fusible conductors

17 and 19 are exposed from the opening 43 through the low melting point metal layer 41, and the contact area between the low melting point metal and the high melting point metal after melting is increased, so that the erosion action of the high melting point metal is further promoted, and the meltability can be improved.

As shown in fig. 16, the first and second

soluble conductors

17 and 19 may have a plurality of openings 44 formed in the high-melting-point metal layer 40 as the inner layer, and the low-melting-point metal layer 41 may be formed on the high-melting-point metal layer 40 by using a plating technique or the like to fill the openings 44. Accordingly, in the first and second

fusible conductors

17 and 19, since the area of the molten low-melting-point metal in contact with the high-melting-point metal is increased, the high-melting-point metal can be melted and corroded by the low-melting-point metal in a shorter time.

The first and second

fusible conductors

17 and 19 are preferably formed so that the volume of the low melting point metal layer 41 is larger than the volume of the high melting point metal layer 40. The first and second

fusible conductors

17 and 19 are heated by the heating element 18, and the low melting point metal melts to erode the high melting point metal, thereby being melted and fused quickly. Therefore, the first and second

fusible conductors

17 and 19 are formed so that the volume of the low melting point metal layer 41 is larger than the volume of the high melting point metal layer 40, and this ablation action is promoted, and the first and

second electrodes

11 and 12 and the fourth and

fifth electrodes

14 and 15 can be cut off quickly.

Description of the symbols

1, 40, 50, 60 cutting element

2 first circuit

3 second circuit

10 insulating substrate

10a surface

10b back side

11 first electrode

12 second electrode

13 third electrode

14 fourth electrode

15 fifth electrode

17 first fusible conductor

18 heating element

19 second fusible conductor

20 through hole

21 insulating member

22 fluxing agent

23 covering member

25 current control element

26 external power supply

27 detection circuit

30 cut-off element circuit

31 external circuit

33 data server

34 internet line

40 high melting point metal layer

41 low melting point metal layer

42 to 44 openings

Claims

1. A cutting element, comprising:

an insulating substrate;

first and second electrodes formed on the insulating substrate to constitute a first circuit;

third to fifth electrodes formed on the insulating substrate to constitute a second circuit;

a first fusible conductor bridged between the first and second electrodes and connected by solder;

a heating element connected between the third and fourth electrodes; and

a second fusible conductor bridged between the fourth and fifth electrodes and connected by solder,

the second fusible conductor is fused after the first fusible conductor is fused by heat generated from the heating element by passing a current between the third to fifth electrodes,

the second circuit is formed in a manner independent of the first circuit,

the first fusible conductor is mounted closer to a heat generation center of the heating element than the second fusible conductor,

the first fusible conductor and/or the second fusible conductor contain a low melting point metal and a high melting point metal,

the low melting point metal is melted by heating from the heating element to erode the high melting point metal,

the first fusible conductor and/or the second fusible conductor is in a covering configuration in which an inner layer is the low melting point metal and an outer layer is the high melting point metal, and is in a configuration in which the high melting point metal covers the low melting point metal except a pair of side surfaces facing each other,

the melting temperature of the low melting point metal is less than the reflow temperature,

the first fusible conductor and/or the second fusible conductor are fused at a temperature higher than a reflow temperature and lower than a melting point of the high-melting-point metal.

2. The severing element of claim 1, wherein the cross-sectional area of the first fusible conductor is smaller than the cross-sectional area of the second fusible conductor.

3. The severing element of claim 1, wherein the length of the first fusible conductor is longer than the length of the second fusible conductor.

4. The shut-off element of claim 1, wherein the first fusible conductor has a lower melting point than the second fusible conductor.

5. The severing element of claim 1,

an insulating layer is provided on a surface of the insulating substrate on which the first to fifth electrodes are formed,

the heat generator is formed between the insulating substrate and the insulating layer or inside the insulating layer.

6. The cutting element according to claim 1, wherein the heat generating body is formed on a surface of the insulating substrate opposite to the surface.

7. The cut-off element according to claim 1, wherein the heat generating body is formed inside the insulating substrate.

8. The cut-off element according to any one of claims 5 to 7, wherein the heat-generating body overlaps with the first and second electrodes.

9. The cutting element according to claim 8, wherein the heat generating body overlaps with the fourth and fifth electrodes.

10. The severing element of claim 1,

the heat generator is formed between the insulating substrate and the insulating layer, and is formed in alignment with the first and second electrodes and the fourth and fifth electrodes.

11. The cutting element according to any one of claims 1, 5 to 7, wherein the first fusible conductor and/or the second fusible conductor is a lead-free solder containing Sn as a main component.

12. The severing element of claim 1,

the low-melting-point metal is a solder,

the high-melting-point metal is Ag, Cu, or an alloy containing Ag or Cu as a main component.

13. The shut-off element according to claim 1, wherein the first fusible conductor and/or the second fusible conductor is a covering construction with an inner layer of a high melting point metal and an outer layer of a low melting point metal.

14. The cutting element according to claim 1, wherein the first fusible conductor and/or the second fusible conductor is a laminated structure in which a low melting point metal and a high melting point metal are laminated.

15. The cutting element according to claim 1, wherein the first fusible conductor and/or the second fusible conductor is a multilayer configuration of 4 or more layers in which a low melting point metal and a high melting point metal are alternately stacked.

16. The cutting element according to claim 1, wherein the first fusible conductor and/or the second fusible conductor is provided with an opening portion in a high melting point metal formed on a surface of a low melting point metal constituting an inner layer.

17. The cutout element of claim 1, wherein the first fusible conductor and/or the second fusible conductor is provided with: the metal layer comprises a high-melting-point metal layer having a plurality of openings, and a low-melting-point metal layer formed on the high-melting-point metal layer, wherein the openings are filled with a low-melting-point metal.

18. The shut-off element according to claim 1, wherein the volume of the low-melting metal of the first fusible conductor and/or the second fusible conductor is greater than the volume of the high-melting metal.

19. A cut-off element circuit is provided with:

a first circuit having a first fusible conductor; and

a second circuit formed independently of the first circuit and having a heating element and a second fusible conductor connected to one end of the heating element,

the heat generated by the heating element by the current flowing through the second circuit is blown off by the first fusible conductor to cut off the first circuit, and then the second fusible conductor is blown off,

the first fusible conductor and/or the second fusible conductor is a covering structure in which an inner layer is the low melting point metal and an outer layer is the high melting point metal, and is a structure in which the high melting point metal covers the low melting point metal except for a pair of side surfaces of the low melting point metal facing each other,

20. The cutting element circuit according to claim 19, wherein in the second circuit, the heating element and the second fusible conductor are connected to a power supply and a switching element, and a current is caused to flow by driving the switching element.