Protective element

Abstract

To provide a protection element with the breakdown possibility being further suppressed.SOLUTION: A protection element comprises: a substrate 30; connection membrane electrodes 32; a fuse element 34; lead conductors 36; cutoff barriers 38; extension part 42; and a cover 44. The cutoff barrier 38 is provided between a location where the fuse element 34 is connected and a location where the lead conductor 36 is connected in the connection membrane electrode 32. The cover covers at least a region from a location where the fuse elements 34 are covered with a flux 40 to a location where the lead conductors 36 are connected with the connection membrane electrodes 32. The extension part 42 is continued to the cutoff barrier 38. The extension part 42 extends to at least an edge of the connection membrane electrode 32.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a protection element.

Background Art

[0002] Patent Document 1 discloses an invention related to a protection element. The protection element according to Patent Document 1 has connection film electrodes on one surface of a substrate. A fuse element is welded across these connection film electrodes. Lead conductors are joined to each connection film electrode by soldering. A cutoff barrier is provided between the fuse element welding location and the lead conductor soldering joint location in each connection film electrode. The cutoff barrier blocks the wetting spread with respect to the molten solder during soldering or the molten alloy during fuse element welding.

[0003] According to the protection element disclosed in Patent Document 1, the distance between the welding location of the fuse element and the joint location of the lead conductor can be shortened without any problem. Thereby, the main body portion of the protection element can be reduced in size.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, there is still room for further improvement in suppressing the possibility of breakage in the protection element disclosed in Patent Document 1. An object of the present invention is to provide a protection element in which the possibility of breakage is further suppressed.

Means for Solving the Problems

[0006] The protection element of the present invention will be described with reference to the drawings. The reference numerals in the drawings are used in this section to assist in understanding the content of the invention, and are not intended to limit the content to the illustrated scope.

[0007] To solve the above problems, according to an aspect of the present invention, the protection element 10 includes a substrate 30, a pair of connection film electrodes 32, 32, a fuse element 34, a pair of lead conductors 36, 36, a pair of cut-off barriers 38, 38, and a cover 44. The pair of connection film electrodes 32, 32 is provided on one surface of the substrate 30. The fuse element 34 is connected across the pair of connection film electrodes 32, 32. The pair of lead conductors 36, 36 is connected onto different connection film electrodes 32, 32 from each other. The cut-off barriers 38, 38 are provided between the location where the fuse element 34 is connected in the connection film electrodes 32, 32 and the location where the lead conductor 36 is connected. The cover 44 covers at least the region from the fuse element 34 to the location where the pair of lead conductors 36, 36 is connected to the connection film electrodes 32, 32. The protection element 10 further includes extension portions 42, 102. The extension portions 42, 102 are continuous with the cut-off barriers 38. The extension portions 42, 102 extend at least to the edge of the connection film electrode 32.

[0008] The cutoff barriers 38, 38 are provided between the locations where the fuse elements 34 in the connection membrane electrodes 32, 32 are connected and the locations where the lead conductors 36 are connected. The extension parts 42, 102 are continuous with the cutoff barriers 38. Various causes due to the fusing of the fuse element 34 generate gas and other fluids. Among the fluids, those flowing near the connection locations with the lead conductors 36 in the connection membrane electrodes 32, 32 are blocked by the cutoff barriers 38 and the extension parts 42, 102. At this time, the extension parts 42, 102 extend at least to the edge of the connection membrane electrode 32. Thereby, compared with the case where the extension parts 42, 102 are not provided, the arrival of the fluid to the location where the lead conductor 36 in the connection membrane electrode 32 is connected is delayed. When the arrival is delayed, compared with the case where it is not, the possibility that the area near that location is damaged by the energy of the fluid is reduced. A pair of connection membrane electrodes 32, 32 is provided on one surface of the substrate 30, and the lead conductor 36 is connected onto the connection membrane electrode 32. The cover 44 covers at least the region from the location where the flux 40 covers the fuse element 34 to the location where the lead conductors 36, 36 are connected to the connection membrane electrodes 32, 32. Thereby, compared with other locations on the substrate 30, the distance to the cover 44 is likely to be closer near the connection locations between the lead conductors 36 and the connection membrane electrodes 32, 32. In this situation, when the possibility that the area near the connection locations between the lead conductors 36 and the connection membrane electrodes 32, 32 is damaged is reduced, the possibility that the protection element 10 is damaged by the damage is reduced. As a result, a protection element 10 with a further reduced possibility of damage is provided.

[0009] Further, it is desirable that the direction from the location where the fuse element 34 is connected to each of the pair of connection membrane electrodes 32, 32 described above to the location where the lead conductor 36 is connected intersects with the direction described below. That direction is the direction in which the fuse element 34 travels from one of the pair of connection membrane electrodes 32, 32 to the other. In this case, it is desirable that the pair of connection membrane electrodes 32, 32 are provided so as to face each other. In this case, it is desirable that each edge of the pair of connection membrane electrodes 32, 32 has a section 160 that extends linearly along each other. In this case, it is desirable that the extension portion 42 has an opposing section portion 60. The opposing section portion 60 is continuous with the blocking barrier 38. The opposing section portion 60 extends beyond the section 160 that extends linearly among the edges of the connection membrane electrode 32.

[0010] The pair of connection membrane electrodes 32, 32 are provided so as to face each other. The direction from the location where the fuse element 34 is connected to each of the pair of connection membrane electrodes 32, 32 to the location where the lead conductor 36 is connected intersects with the direction described below. That direction is the direction in which the fuse element 34 travels from one of the pair of connection membrane electrodes 32, 32 to the other. The blocking barrier 38 is provided between the location where the fuse element 34 is connected and the location where the lead conductor 36 is connected in the connection membrane electrode 32. The opposing section portion 60 is continuous with the blocking barrier 38. The opposing section portion 60 extends beyond the section 160 that extends linearly among the edges of the connection membrane electrode 32. As a result, the arrival at the location where the lead conductor 36 is connected to the connection membrane electrode 32 via the section described below of the fluid described below is delayed. The fluid is caused by various causes resulting from the melting of the fuse element 34. The section is the section 160 that extends linearly among the edges of the connection membrane electrode 32. When the arrival is delayed, the possibility that the vicinity of that location is damaged by the energy of the fluid is lower than in the case where it is not. When the possibility is lower, the possibility that the protection element 10 is damaged by that damage is lower. As a result, a protection element 10 with a reduced possibility of damage is provided.

[0011] Alternatively, it is desirable that the above-described extension part 42 has the opposing section part 62 in addition to the opposing section part 60. The opposing section part 62 is continuous with the blocking barrier 38. The opposing section part 62 extends at least beyond the section 162 described below. The section 162 is a section on the side opposite to the other side of the pair of connection membrane electrodes 32, 32 as seen from one of the pair of connection membrane electrodes 32, 32 among the edges of the connection membrane electrode 32.

[0012] The extension part 42 has the opposing section part 62. As a result, compared to the case where it does not, the arrival of the fluid that has flowed along the blocking barrier 38 toward the opposing section part 62 side among the above-described fluids to the location where the lead conductor 36 in the connection membrane electrode 32 is connected is delayed. When the arrival is delayed, compared to the case where it does not, the possibility that the vicinity of that location is damaged by the energy of the fluid is reduced. When the possibility that the vicinity is damaged is reduced, the possibility that the protection element 10 is damaged by that damage is reduced. As a result, a protection element 10 with a reduced possibility of damage is provided.

[0013] Also, it is desirable that the above-described extension part 102 has the roadside forming part 140 and the closing part 142. The roadside forming part 140 spreads along the edge of the connection membrane electrode 32. The closing part 142 closes the space between the roadside forming part 140 and the blocking barrier 38.

[0014] The roadside forming part 140 spreads in the direction in which the edge of the connection membrane electrode 32 extends. When the roadside forming part 140 spreads in that direction, at least a part of the fluid generated due to various causes resulting from the fusing of the fuse element 34 flows along the roadside forming part 140 in the connection membrane electrode 32. When the fluid flows in such a manner, it becomes difficult for the fluid to approach the location where the lead conductor 36 is connected. As a result, the possibility that the vicinity of that location is damaged by the energy of the fluid is reduced. When the possibility that the vicinity is damaged is reduced, the possibility that the protection element 10 is damaged by that damage is reduced. As a result, a protection element 10 with a reduced possibility of damage is provided.

[0015] Alternatively, it is desirable that the edge of the connection membrane electrode 32 described above has a linearly extending section 160. In this case, it is desirable that the roadside forming portion 140 extends along the linearly extending section 160 of the edge of the connection membrane electrode 32.

[0016] The fluid generated due to various causes resulting from the fusing of the fuse element 34 flows along the roadside forming portion 140. When the roadside forming portion 140 extends along the linearly extending section 160 of the edge of the connection membrane electrode 32, the fluid will flow linearly. As a result, the possibility that the fluid quickly passes by the connection membrane electrode 32 increases. When this possibility increases, the possibility that the area near the location where the lead conductor 36 is connected in the connection membrane electrode 32 is damaged by the energy of the fluid decreases. When the possibility of damage to that area decreases, the possibility that the protection element 10 is damaged by that damage decreases. As a result, a protection element 10 with a reduced possibility of damage is provided.

[0017] Also, it is desirable that the direction from the location where the fuse element 34 is connected to the location where the lead conductor 36 is connected in each pair of the above-described connection membrane electrodes 32, 32 intersects with the direction described below. That direction is the direction in which the fuse element 34 goes from one of the pair of connection membrane electrodes 32, 32 to the other. In this case, it is desirable that the pair of connection membrane electrodes 32, 32 are provided so as to face each other. In this case, it is desirable that the edges of each of the pair of connection membrane electrodes 32, 32 have linearly extending sections 160 that extend linearly along each other. In this case, it is desirable that cutoff barriers 38, 38 are provided on each of the pair of connection membrane electrodes 32, 32. In this case, it is desirable that extension portions 42, 102 are connected to each of the pair of cutoff barriers 38, 38. In this case, it is desirable that the extension portions 42, 102 connected to each of the pair of cutoff barriers 38, 38 face each other with a gap therebetween.

[0018] The locations where the pairs of the extensions 42, 102 face each other with a gap therebetween serve as the flow paths for the above-described fluid. When the extensions 42, 102 are connected to each of the pairs of the blocking barriers 38, 38, the gap at the location where the pairs of the extensions 42, 102 face each other with a gap therebetween becomes narrower than when the extensions 42, 102 are connected to only one of the pairs of the blocking barriers 38, 38. When the gap becomes narrower, the flow velocity of the above-described fluid at that location becomes faster. Each of the pairs of the connection membrane electrodes 32, 32 has a section 160 that linearly extends such that the edges thereof are along each other, and when the flow velocity of the above-described fluid becomes faster, the following is likely to occur. That possibility is that the above-described fluid that has passed through the location where the pairs of the extensions 42, 102 face each other with a gap therebetween passes by the connection membrane electrode 32. When that possibility becomes higher, the possibility that the vicinity of the location where the lead conductor 36 is connected is damaged by the energy of the fluid is lower than when that is not the case. When the possibility that the vicinity thereof is damaged becomes lower, the possibility that the protective element 10 is damaged by that damage becomes lower. As a result, the protective element 10 with the possibility of damage suppressed is provided.

Advantages of the Invention

[0019] According to the present invention, a protective element with an even further suppressed possibility of damage is provided.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0021] The present invention will be described in detail below with reference to the drawings. In the following description, the same reference numerals are given to the same components. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

[0022] [Description of Configuration] FIG. 1 is a perspective view of a protection element 10 according to the present embodiment. In FIG. 1, the protection element 10 is shown in an assembled state. FIG. 2 is a view showing a substrate 30 of the protection element 10 according to the present embodiment and components provided thereon. Based on FIGS. 1 and 2, the configuration of the protection element 10 according to the present embodiment will be described.

[0023] The protection element 10 according to the present embodiment includes a substrate 30, a pair of connection film electrodes 32, 32, a fuse element 34, a pair of lead conductors 36, 36, a pair of cutoff barriers 38, 38, a flux 40, a pair of extension portions 42, 42, a cover 44, a sealing body 46, and a pair of electric wires 48, 48.

[0024] In the case of the present embodiment, the substrate 30 is a rectangular flat plate made of ceramic. A pair of connection film electrodes 32, 32 is provided on one surface of the substrate 30. In the case of the present embodiment, the shape of the connection film electrode 32 is an "L" shape. As is clear from FIG. 2, the pair of connection film electrodes 32, 32 are provided so as to face each other. As a result, a linear section 160 that is a part of one edge of the pair of connection film electrodes 32, 32 faces a linear section 160 that is a part of the other edge of the pair of connection film electrodes 32, 32. As a result, the linear sections 160 of each of the pair of connection film electrodes 32, 32 are along each other, and they extend linearly.

[0025] The fuse element 34 is connected across the pair of connection membrane electrodes 32, 32. As a result, the fuse element 34 spans from one end of one of the pair of connection membrane electrodes 32, 32 to the other end of the other. When a current flows through the fuse element 34 and its temperature reaches a predetermined temperature, the fuse element 34 melts. When the fuse element 34 melts, the current flowing from one of the pair of connection membrane electrodes 32, 32 to the other is interrupted.

[0026] The pair of lead conductors 36, 36 are electrodes. A current flows through the protection element 10 according to this embodiment via these. The pair of lead conductors 36, 36 are connected to different connection membrane electrodes 32, 32. Thereby, the current flowing through one of the pair of lead conductors 36, 36 also flows through one of the pair of connection membrane electrodes 32, 32. In the case of this embodiment, the lead conductor 36 is connected to the other end of the connection membrane electrode 32. Thereby, the direction from the location where the fuse element 34 is connected to the location where the lead conductor 36 is connected in each of the pair of connection membrane electrodes 32, 32 intersects with the direction described below. That direction is the direction in which the fuse element 34 goes from one of the pair of connection membrane electrodes 32, 32 to the other.

[0027] The pair of cutoff barriers 38, 38 are provided between the location where the fuse element 34 is connected and the location where the lead conductor 36 is connected in each of the connection membrane electrodes 32, 32. The cutoff barrier 38 blocks the melted fuse element 34 and the gas described later.

[0028] The flux 40 contains a synthetic resin. The flux 40 covers the fuse element 34. In the case of this embodiment, the flux 40 covers, in addition to the fuse element 34, most of the pair of connection membrane electrodes 32, 32, the region of the substrate 30 sandwiched between the pair of connection membrane electrodes 32, 32, and the pair of cutoff barriers 38, 38. In FIG. 2, this is shown in a state where most of the flux 40 has been removed.

[0029] Pairs of the extension parts 42, 42 are connected to respective pairs of the blocking barriers 38, 38. In the case of this embodiment, the extension part 42 is integrated with the blocking barrier 38. When gas is generated due to various causes resulting from the fusing of the fuse element 34, the extension part 42 guides the gas flowing on the connection membrane electrode 32 among the gas to the substrate 30 around the connection membrane electrode 32.

[0030] In the case of this embodiment, the cover 44 covers the pair of connection membrane electrodes 32, 32, the fuse element 34, the pair of lead conductors 36, 36, the pair of blocking barriers 38, 38, the flux 40, and the pair of extension parts 42, 42. As a result, the cover 44 covers the location where the pair of lead conductors 36, 36 are connected to the connection membrane electrodes 32, 32.

[0031] The sealing body 46 is disposed between the substrate 30 and the outer edge of the cover 44. The material of the sealing body 46 is a synthetic resin. The sealing body 46 seals the pair of connection membrane electrodes 32, 32, the fuse element 34, the pair of lead conductors 36, 36, the pair of blocking barriers 38, 38, the flux 40, and the pair of extension parts 42, 42.

[0032] The electric wires 48, 48 are connected to the pair of lead conductors 36, 36 in a one-to-one manner. The electric wire 48 transmits current to the lead conductor 36.

[0033] FIG. 3 is an enlarged view of the vicinity of the extension parts 42, 42 in the protection element 10 according to this embodiment. Based on FIG. 3, the configuration of the extension part 42 according to this embodiment will be described. In the case of this embodiment, the extension part 42 has an opposing section part 60 and a non-opposing section part 62.

[0034] The opposing section 60 is continuous with the blocking barrier 38. In the case of this embodiment, the opposing section 60 extends beyond the linear section 160 among the edges of the connecting film electrode 32. As a result, the ends of the opposing section 60 will be located on the substrate 30. Consequently, the extension part 42 extends beyond the edge of the connecting film electrode 32. As described above, the pair of extension parts 42, 42 is continuous with each of the pair of blocking barriers 38, 38. Thereby, the opposing sections 60 respectively possessed by the pair of extension parts 42, 42 face each other with an interval therebetween.

[0035] The opposite section 62 is also continuous with the blocking barrier 38. In the case of this embodiment, the opposite section 62 extends beyond the opposite side section 162 described below. The opposite side section 162 is a section on the opposite side of the pair of connecting film electrodes 32, 32 as seen from one of the pair of connecting film electrodes 32, 32 among the edges of the connecting film electrode 32. As a result, the ends of the opposite section 62 will also be located on the substrate 30.

[0036] [Description of operation] When current flows through the protection element 10 according to this embodiment, the fuse element 34 generates heat. When the magnitude of the current becomes equal to or greater than a predetermined magnitude, the fuse element 34 reaches a predetermined temperature. The fuse element 34 that has reached the predetermined temperature melts. When the fuse element 34 melts, the connection between the pair of connecting film electrodes 32, 32 is interrupted. In parallel with that, gas is generated due to various causes resulting from the fusing of the fuse element 34. Examples of the causes of gas generation include the vaporization of the components of the fuse element 34 and the heating of the flux 40 by the arc generated by the fusing of the fuse element 34. The generated gas spreads around. Also, in the fusing of the fuse element 34, in addition to the generation of gas, there is the scattering of its components and the flow of the melted fuse element 34. Those also spread around. Some of them may be mixed into the gas.

[0037] When the above-described gas contacts the opposing section 60 of the extension part 42, a part of the gas flows along the opposing section 60. As a result, the pair of opposing sections 60, 60 induces a part of the gas between the pair of connection film electrodes 32, 32 on the substrate 30. The gas induced there flows as it is and hits the inner wall of the sealing body 46. When the gas hits the inner wall of the sealing body 46, a part of the kinetic energy of the gas becomes thermal energy and other energies. Thereafter, the gas circulates in the cover 44.

[0038] [Description of Effects] In the protection element 10 according to the present embodiment, the arrival of the above-described gas at the location where the lead conductor 36 is connected to the connection film electrode 32 is delayed. When the arrival is delayed, there is a high possibility that the energy of the gas is taken away by the surrounding objects as thermal energy and other energies while the arrival is delayed. When the energy of the gas is taken away, the possibility that the vicinity of the location where the lead conductor 36 is connected to the connection film electrode 32 is damaged by the energy of the gas is reduced. As a result, a protection element 10 with a further reduced possibility of breakage is provided.

[0039] Moreover, in the protection element 10 according to the present embodiment, the opposing section 60 extends beyond the linear section 160 among the edges of the connection film electrode 32. As a result, the arrival of the above-described gas is further delayed. Since the arrival is further delayed, the possibility that the vicinity of the location where the lead conductor 36 is connected to the connection film electrode 32 is damaged by the energy of the gas is further reduced.

[0040] Furthermore, in the protection element 10 according to the present embodiment, the extension part 42 has the opposing section 62. As a result, compared with the case where it is not so, the arrival of the gas that has flowed along the blocking barrier 38 to the side of the opposing section 62 at the location where the lead conductor 36 is connected to the connection film electrode 32 is delayed. Since the arrival is delayed, the possibility that the vicinity of the location is damaged by the energy of the gas is reduced.

[0041] The portions where the pairs of the opposing interval portions 60, 60 face each other with a gap therebetween serve as the above-described gas flow paths. The pairs of the opposing interval portions 60, 60 extend beyond the intervals 160, 160 where the pairs of the connection membrane electrodes 32, 32 face each other among the edges of the connection membrane electrodes 32. As a result, the portions where the pairs of the opposing interval portions 60, 60 face each other with a gap therebetween become narrower. When such portions become narrower, the flow velocity of the above-described fluid becomes faster at such portions. When the flow velocity of the above-described fluid thus becomes faster, the possibility that the above-described fluid that has passed through such portions reaches the portions where the fluid is connected to the lead conductors 36 in the connection membrane electrodes 32 becomes lower. Since such possibility becomes lower, the possibility that the vicinity of such portions is damaged by the energy possessed by the gas becomes lower.

[0042] <Description of Modification Example> The above-described protection element 10 is an example illustrated for embodying the technical idea of the present invention. The above-described protection element 10 can be variously modified within the scope of the technical idea of the present invention.

[0043] For example, the extension portion 42 may be provided only on one of the pairs of the connection membrane electrodes 32, 32. The extension portion 42 does not have to be integral with the blocking barrier 38. When the blocking barriers 38 are provided on both of the pairs of the connection membrane electrodes 32, 32 and the opposing interval portions 60, 60 are provided for each of them, they do not have to face each other. The extension portion 42 may have only the opposing interval portion 60, or may have only the opposite interval portion 62. The shapes of the intervals 160, 160, which are parts of the edges of each of the pairs of the connection membrane electrodes 32, 32 and extend along each other, do not have to be linear.

[0044] FIG. 4 is an enlarged view of the vicinity of the extension portion 102 in the protection element according to a modification example of the invention according to the above-described embodiment. Based on FIG. 4, the configuration of the extension portion 102 according to this modification example will be described.

[0045] The protection element according to this modification example has different extension parts 102, 102 instead of the above-described extension parts 42, 42. The extension part 102 according to this modification example has an opposing section 120 and an opposite section 122. The opposing section 120 is continuous with the blocking barrier 38. The opposing section 120 according to this modification example is integral with the blocking barrier 38. The opposing section 120 extends at least up to the linear section 160 of the edge of the connection film electrode 32. The opposite section 122 is continuous with the blocking barrier 38. The opposite section 122 according to this modification example is integral with the blocking barrier 38. The opposite section 122 extends at least up to the opposite side section 162. The opposite side section 162 is a section on the opposite side of the other of the pair of connection film electrodes 32, 32 as seen from one of the pair of connection film electrodes 32, 32 at the edge of the connection film electrode 32.

[0046] The opposing section 120 has a side groove forming part 140 and a closing part 142. The side groove forming part 140 spreads along the edge of the connection film electrode 32. As is clear from FIG. 4, the side groove forming part 140 according to this modification example extends along the linearly extending edge of the connection film electrode 32. The closing part 142 closes the space between the side groove forming part 140 and the blocking barrier 38.

[0047] In the protection element according to this modification example, the side groove forming part 140 spreads in the direction in which the edge of the connection film electrode 32 extends. When the side groove forming part 140 spreads in that direction, at least a part of the gas generated due to various causes resulting from the fusing of the fuse element 34 flows along the side groove forming part 140 in the connection film electrode 32. When the gas flows in such a manner, it becomes difficult for the gas to approach the location where the lead conductor 36 is connected. As a result, the possibility that the area near that location is damaged by the energy of the gas is reduced. When the possibility that the area near that location is damaged is reduced, the possibility that the protection element according to this modification example is damaged by that damage is reduced.

[0048] Moreover, the gas flows along the side-channel forming portion 140. When the side-channel forming portion 140 extends along the linear section 160 of the edge of the connection membrane electrode 32, the gas will flow linearly. As a result, it is highly likely that the fluid will quickly pass by the connection membrane electrode 32. When this likelihood increases, the possibility that the area near the location where the lead conductor 36 is connected to the connection membrane electrode 32 is damaged by the energy carried by the inflowing gas is reduced.

Explanation of Signs

[0049] 10…Protection element 30…Substrate 32…Connection membrane electrode 34…Fuse element 36…Lead conductor 38…Blocking barrier 40…Flux 42, 102…Extension portion 44…Cover 46…Sealing body 48…Electric wire 60, 120…Opposing section portion 62, 122…Opposite section portion 140…Side-channel forming portion 142…Blocking portion 160…Linear section 162…Opposite side section

Claims

1. A substrate, A pair of connection film electrodes provided on one surface of the substrate, A fuse element connected across the pair of connection film electrodes, A pair of lead conductors connected to the different connection film electrodes, A cutoff barrier provided between a location where the fuse element is connected and a location where the lead conductor is connected in the connection film electrode, A protective element comprising a cover that at least covers a region from the fuse element to a location where the protective element is connected to the connection film electrode of the pair of lead conductors, The protective element further comprising an extension portion that is continuous with the cutoff barrier and extends at least to an edge of the connection film electrode.

2. The direction from the location where the fuse element is connected to the location where the lead conductor is connected in each of the pair of connection film electrodes intersects with the direction in which the fuse element goes from one of the pair of connection film electrodes to the other, The pair of connection film electrodes are provided so as to face each other, Edges of each of the pair of connection film electrodes have a section that linearly extends along each other, The protective element according to claim 1, wherein the extension portion is continuous with the cutoff barrier and has an opposing section portion that extends beyond the section that linearly extends among the edges of the connection film electrode.

3. The protective element according to claim 2, wherein the extension portion is continuous with the cutoff barrier and, in addition to the opposing section portion, has an opposing section portion that extends at least beyond a section on the opposite side of the other of the pair of connection film electrodes as viewed from one of the pair of connection film electrodes among the edges of the connection film electrode.

4. The extension portion, A sidewall forming portion that spreads along an edge of the connection film electrode, The protective element according to claim 1, further comprising a closing portion that closes a space between the sidewall forming portion and the cutoff barrier.

5. Edges of the connection film electrode have a section that linearly extends, The protective element according to claim 4, wherein the sidewall forming portion spreads along the section that linearly extends of the edge of the connection film electrode.

6. The direction from the location where the fuse element is connected to the location where the lead conductor is connected in each of the pair of connection film electrodes intersects with the direction in which the fuse element goes from one of the pair of connection film electrodes to the other, The pair of the connection membrane electrodes is provided so as to face each other, each edge of the pair of the connection membrane electrodes has a section that linearly extends along each other, the blocking barrier is provided on each of the pair of the connection membrane electrodes, the extension part is continuous with each of the pair of the blocking barriers, The protection element according to claim 1, wherein the extension parts that are continuous with each of the pair of the blocking barriers face each other with a gap therebetween.

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