CN115938888A - Protective element - Google Patents

Abstract

The invention provides a protective element which further inhibits the possibility of breakage. The protection element has: a substrate (30), a connection membrane electrode (32), a fusible body (34), a lead conductor (36), a shield (38), an extension (42), and a cover. A shielding member (38) is provided between a portion of the connection membrane electrode (32) that is connected to the fusible body (34) and a portion that is connected to the lead conductor (36). The cover (44) covers at least the region from the portion where the flux (40) covers the fusible body (34) to the portion of the lead conductor (36) connected to the connection membrane electrode (32). The extension (42) is connected to the shield (38). The extension portion (42) extends at least to the edge of the connection membrane electrode (32).

Description

Protective element

Technical Field

The present invention relates to a protective element.

Background

Patent document 1 discloses an invention relating to a protective element. The protection element of patent document 1 has a connection membrane electrode on one surface of a substrate. The fusible body is welded to the connecting film electrodes. Lead conductors are soldered to the respective connection film electrodes. A shielding material is provided between the fusible body welding portion and the lead conductor solder bonding portion in each connection membrane electrode. The shield shields against wet spread of molten solder during brazing or molten alloy during fusion bonding.

According to the protection element disclosed in patent document 1, the distance between the fusible bonding portion and the lead conductor bonding portion can be reduced without hindrance. This makes it possible to reduce the size of the main body of the protection element.

Patent document 1: japanese patent laid-open No. 2009-070804.

Disclosure of Invention

However, the protective element disclosed in patent document 1 has room for further improvement in terms of suppressing the possibility of breakage. The invention aims to provide a protective element which further inhibits the possibility of damage.

The protective element of the present invention is described with reference to the accompanying drawings. It should be noted that the reference numerals are used in this specification to help understanding the contents of the invention, and are not intended to limit the contents to the scope shown in the drawings.

In order to solve the above problem, according to one aspect of the present invention, a protection element 10 includes: a substrate 30, a pair of connection membrane electrodes 32, a fusible body 34, a pair of lead conductors 36, a pair of shutters 38, and a cover 44. A pair of connection membrane electrodes 32, 32 are provided on one surface of the substrate 30. A fusible body 34 bridges the pair of joining membrane electrodes 32, 32. A pair of lead conductors 36, 36 are connected to the connection-use membrane electrodes 32, 32 different from each other. The blindfold members 38, 38 are provided between the portions of the connection film electrodes 32, 32 connected to the fusible body 34 and the portions connected to the lead conductors 36. The cover 44 covers at least the region from the fusible element 34 to the portion of the pair of lead conductors 36, 36 connected to the connection membrane electrodes 32, 32. The protective element 10 also has extensions 42, 102. The extensions 42, 102 are connected to the shield 38. The extensions 42, 102 extend at least to the edge of the membrane electrode for connection 32.

The blindfold members 38, 38 are provided between the portions of the connection film electrodes 32, 32 connected to the fusible body 34 and the portions connected to the lead conductors 36. The extensions 42, 102 are connected to the shield 38. Fluids such as gases are generated for various reasons caused by the melting of the meltable material 34. Of the fluid, the fluid flowing toward the vicinity of the portion of the connection membrane electrodes 32, 32 connected to the lead conductor 36 is blocked by the blocking member 38 and the extensions 42, 102. At this time, the extensions 42 and 102 extend at least to the edge of the connection membrane electrode 32. This delays the arrival of the fluid at the portion of the connection membrane electrode 32 connected to the lead conductor 36, compared to the case where the extensions 42, 102 are not provided. If the arrival is delayed, the possibility that the vicinity of the site is damaged by the energy of the fluid is reduced as compared with the case where the arrival is not delayed. A pair of connection membrane electrodes 32, 32 are provided on one surface of the substrate 30, and lead conductors 36 are connected to the connection membrane electrodes 32. The cover 44 covers at least the region from the portion where the flux 40 covers the fusible member 34 to the portion of the pair of lead conductors 36, 36 connected to the connection film electrodes 32, 32. This makes it possible to reduce the distance from the cover 44 in the vicinity of the portion of the connection membrane electrodes 32, 32 connected to the lead conductor 36, as compared with other portions on the substrate 30. In this situation, if the vicinity of the portion of the connection membrane electrodes 32, 32 connected to the lead conductor 36 is less likely to be damaged, the protective element 10 is less likely to be damaged by the damage. As a result, the protective element 10 is provided which further suppresses the possibility of breakage.

In addition, it is preferable that the direction from the portion of each of the pair of connection film electrodes 32, 32 connected to the fusible body 34 toward the portion connected to the lead conductor 36 intersects with the direction described below. This direction is a direction in which the fusible body 34 faces one of the pair of connection film electrodes 32, 32 toward the other. In this case, it is preferable that a pair of the connection- use membrane electrodes 32, 32 be provided so as to oppose each other. In this case, it is preferable that the edge of each of the pair of connection- use membrane electrodes 32, 32 has a section 160 extending linearly along each other. In this case, the extension 42 preferably has opposing intermediate portions 60. The opposite section 60 is connected to the shield 38. The opposing section 60 extends beyond a section 160 extending linearly in the edge of the connection membrane electrode 32.

The pair of connection membrane electrodes 32, 32 are disposed to face each other. A direction from a portion connected to the fusible body 34 in each of the pair of connection- use film electrodes 32, 32 toward a portion connected to the lead conductor 36 intersects with a direction described below. This direction is a direction in which the fusible body 34 faces one of the pair of connection film electrodes 32, 32 toward the other. The blindfold 38 is provided between the portion of the connection film electrode 32 connected to the fusible body 34 and the portion connected to the lead conductor 36. The opposite intermediate portion 60 is connected to the shield 38. The opposing section 60 extends beyond a section 160 extending in a straight line in the edge of the connection membrane electrode 32. Thereby, the fluid passing through the below-described section among the below-described fluids reaches the portion of the connection membrane electrode 32 connected to the lead conductor 36 with a delay. The fluid is a fluid resulting from various causes resulting from the melting of the meltable body 34. This section is a section 160 extending linearly in the edge of the connection membrane electrode 32. If the arrival is delayed, the possibility that the vicinity of the site is damaged by the energy of the fluid is reduced as compared with the case where the arrival is not delayed. If this possibility is reduced, the possibility that the protection element 10 is broken by the damage becomes low. As a result, the protective element 10 is provided that suppresses the possibility of breakage.

Alternatively, and preferably, the extension 42 has an opposing intermediate portion 62 in addition to the opposing intermediate portion 60. The opposite intermediate portion 62 is connected to the shield 38. The opposite section 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 when viewed from one of the pair of connection membrane electrodes 32, of the edges of the connection membrane electrode 32.

The extension 42 has an opposite intermediate portion 62. Thus, the fluid flowing along the shield 38 toward the opposite intermediate portion 62 among the above-described fluids reaches the portion of the connection membrane electrode 32 connected to the lead conductor 36 with a delay, as compared with the case where the opposite intermediate portion 62 is not provided. If the arrival is delayed, the possibility that the vicinity of the site is damaged by the energy of the fluid is reduced as compared with the case where the arrival is not delayed. If the possibility of damage to the vicinity is reduced, the possibility of breakage of the protection element 10 due to the damage is reduced. As a result, the protective element 10 is provided in which the possibility of breakage is suppressed.

In addition, the extension 102 preferably has a roadside formation portion 140 and an occlusion portion 142. The roadside formation portion 140 spreads along the edge of the connection-use membrane electrode 32. The blocking portion 142 blocks the gap between the roadside forming portion 140 and the shutter 38.

The roadside formation portion 140 spreads in the direction in which the edge of the connection-use membrane electrode 32 extends. If the roadside formation portion 140 expands in this direction, at least a portion of the fluid generated due to various causes caused by the fusion of the fusible body 34 flows along the roadside formation portion 140 in the membrane electrode for connection 32. When the fluid thus flows, it is difficult for the fluid to access the portion to which the lead conductor 36 is connected. This reduces the possibility that the vicinity of the portion is damaged by the energy of the fluid. If the possibility of damage to the vicinity is reduced, the possibility of breakage of the protection element 10 due to the damage is reduced. As a result, the protective element 10 is provided in which the possibility of breakage is suppressed.

Alternatively, the edge of the connection membrane electrode 32 preferably has a section 160 extending linearly. In this case, the roadside formation portion 140 preferably expands along the linearly extending section 160 of the edge of the connection membrane electrode 32.

Fluids resulting from various causes resulting from the fusing of the meltable material 34 flow along the wayside formation 140. If the roadside formation portion 140 expands along the section 160 of the edge of the membrane electrode for connection 32 that extends in a straight line, the fluid flows in a straight line. This increases the possibility that the fluid passes through the vicinity of the connection membrane electrode 32 quickly. If this possibility becomes high, the possibility that the vicinity of the portion of the connection membrane electrode 32 connected to the lead conductor 36 is damaged by the energy of the fluid is reduced. If the possibility of damage to the vicinity is reduced, the possibility of breakage of the protection element 10 due to the damage is reduced. As a result, the protective element 10 is provided in which the possibility of breakage is suppressed.

In addition, it is preferable that the direction from the portion of each of the pair of connection- use membrane electrodes 32, 32 connected to the fusible body 34 toward the portion connected to the lead conductor 36 intersects with the direction described below. This direction is a direction in which the fusible body 34 faces one of the pair of connection film electrodes 32, 32 toward the other. In this case, it is preferable that a pair of the connection- use membrane electrodes 32, 32 be provided so as to oppose each other. In this case, it is preferable that the edge of each of the pair of connection- use membrane electrodes 32, 32 has a section 160 extending linearly along each other. In this case, it is preferable that the blinders 38, 38 be provided on each of the pair of connection-use membrane electrodes 32, respectively. In this case, the extensions 42, 102 are preferably connected to a pair of shutters 38, respectively. In this case, it is preferred that the extensions 42, 102 associated with each of the pair of shutters 38, 38 be opposed to each other at a spaced interval.

The pair of extensions 42 and 102 are opposed to each other with a gap therebetween and serve as the fluid flow path. When the extensions 42, 102 are connected to the pair of shutters 38, respectively, the gap between the portions of the pair of extensions 42, 102 that face each other at a distance is narrowed, as compared to the case where the extensions 42, 102 are connected to only one of the pair of shutters 38, 38. If the gap is narrowed, the flow velocity of the fluid becomes fast at that portion. The possibility described below becomes high if the edge of each of the pair of connection- use membrane electrodes 32, 32 has a section 160 that extends linearly along each other and the flow rate of the fluid described above becomes fast. This possibility is a possibility that the fluid passing through the portion where the pair of extensions 42 and 102 are opposed to each other with a space therebetween passes by the connection membrane electrode 32. If the possibility is high, the possibility that the vicinity of the portion to which the lead conductor 36 is connected is damaged by the energy of the fluid is lower than in the case where the possibility is not high. If the possibility of damage to the vicinity is reduced, the possibility of breakage of the protection element 10 due to the damage is reduced. As a result, the protective element 10 is provided in which the possibility of breakage is suppressed.

According to the present invention, a protective element is provided in which the possibility of breakage is further suppressed.

Drawings

Fig. 1 is a perspective view of a protective element according to an embodiment of the present invention.

Fig. 2 is a diagram showing a substrate of a protective element and a member provided on the substrate according to an embodiment of the present invention.

Fig. 3 is an enlarged view showing the vicinity of an extension in a protective member according to an embodiment of the present invention.

Fig. 4 is an enlarged view showing the vicinity of an extended portion in a protective element according to a modification of the embodiment of the present invention.

Description of the reference numerals:

10. protective element

30. Substrate board

32. Membrane electrode for connection

34. Meltable body

36. Lead conductor

38. Shielding piece

40. Welding flux (flux)

42. 102 extension part

44. Cover

46. Sealing body

48. Electric wire

60. 120 relative interval part

62. 122 opposite intermediate portion

140. Roadside formation part

142. Blocking part

160. Linear section

162. Section of the opposite side

Detailed Description

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

[ description of the structures ]

Fig. 1 is a perspective view of a protection element 10 of the present embodiment. In fig. 1, the protective element 10 is shown in an assembled state. Fig. 2 is a diagram showing a substrate 30 of the protection element 10 according to the present embodiment and components provided on the substrate 30. The structure of the protection element 10 of the present embodiment will be described with reference to fig. 1 and 2.

The protection element 10 of the present embodiment includes: a substrate 30, a pair of connection membrane electrodes 32, a fusible body 34, a pair of lead conductors 36, a pair of shielding members 38, solder 40, a pair of extensions 42, a cover 44, a sealing body 46, and a pair of wires 48, 48.

In the case of the present embodiment, the substrate 30 is made of ceramic and is a rectangular flat plate. A pair of connection membrane electrodes 32, 32 is provided on one surface of the substrate 30. In the present embodiment, the connection membrane electrode 32 has an L-shape. As can be seen from fig. 2, the pair of connection membrane electrodes 32, 32 are disposed so as to face each other. As a result, the linear section 160, which is a part of the edge of one of the pair of connection membrane electrodes 32, faces the linear section 160, which is a part of the edge of the other of the pair of connection membrane electrodes 32, 32. As a result, the linear sections 160 of the pair of connection membrane electrodes 32, 32 are along each other, and they extend linearly.

A fusible body 34 bridges the pair of joining membrane electrodes 32, 32. As a result, the fusible body 34 spans one end of one of the pair of connection film electrodes 32, 32 and one end of the other connection film electrode 32. When current flows through the fusible body 34 and the temperature of the fusible body 34 reaches a prescribed temperature, the fusible body 34 melts. When the fusible body 34 melts, the current flowing from one of the pair of joining film electrodes 32, 32 to the other is cut off.

The pair of lead conductors 36, 36 are electrodes. A current flows through the protection element 10 of the present embodiment through the pair of lead conductors 36, 36. The pair of lead conductors 36, 36 are connected to the mutually different connection- use membrane electrodes 32, 32. Thus, 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 present embodiment, the lead conductor 36 is connected to the other end of the connection membrane electrode 32. Thereby, the direction from the portion connected to the fusible body 34 in each of the pair of connection- use film electrodes 32, 32 toward the portion connected to the lead conductor 36 intersects with the direction described below. This direction is a direction in which the fusible body 34 faces one of the pair of connection- use membrane electrodes 32, 32 toward the other.

A pair of blinders 38, 38 is provided between a site connected to the fusible body 34 and a site connected to the lead conductor 36 in each of the connection- use membrane electrodes 32, 32. The shielding material 38 shields the melted fusible body 34 from a gas described later.

The flux 40 comprises a synthetic resin. The flux 40 covers the meltable body 34. In the case of the present embodiment, the flux 40 covers most of the pair of joining membrane electrodes 32, the region of the substrate 30 sandwiched between the pair of joining membrane electrodes 32, and the pair of blinders 38, 38 in addition to the fusible body 34. Fig. 2 shows a state where most of the flux 40 is removed.

A pair of extensions 42, 42 are connected to the pair of shutters 38, respectively. In the case of this embodiment, the extension 42 is integral with the shield 38. When gas is generated due to various causes caused by the fusion of the fusible body 34, the extension portion 42 guides the gas flowing on the connection membrane electrode 32 among the gas to the substrate 30 around the connection membrane electrode 32.

In the case of the present embodiment, the cover 44 covers the pair of connection film electrodes 32, the fusible body 34, the pair of lead conductors 36, the pair of shutters 38, the solder 40, and the pair of extensions 42, 42. As a result, the cover 44 covers the portions of the pair of lead conductors 36, 36 connected to the connection membrane electrodes 32, 32.

The seal 46 is disposed between the substrate 30 and the outer edge of the cover 44. The raw material of the sealing body 46 is synthetic resin. The sealing body 46 seals the pair of connection membrane electrodes 32, the fusible body 34, the pair of lead conductors 36, the pair of shields 38, the flux 40, and the pair of extensions 42, 42.

The electric wires 48, 48 are connected to the pair of lead conductors 36, 36 one for one. The wire 48 delivers current to the lead conductor 36.

Fig. 3 is an enlarged view of the vicinity of the extensions 42, 42 in the protective member 10 of the present embodiment. The structure of the extension 42 of the present embodiment will be described with reference to fig. 3. In the case of the present embodiment, the extension 42 has an opposing section 60 and an opposing section 62.

The opposite section 60 is connected to the shield 38. In the case of the present embodiment, the opposing section 60 extends beyond the linear section 160 in the edge of the connection membrane electrode 32. As a result, the end of the opposing section 60 is positioned on the substrate 30. Further, the extension portion 42 extends beyond the edge of the connection membrane electrode 32. As described above, a pair of extensions 42, 42 are connected to a pair of blinders 38, respectively. Thus, the opposing sections 60 of the pair of extensions 42, 42 are spaced apart and opposed to each other.

The opposite section 62 is also connected to the shield 38. In the case of the present embodiment, the opposite side section 62 extends beyond the opposite side section 162 described below. The opposite-side section 162 is a section on the side opposite to the other side of the pair of connection membrane electrodes 32, 32 when viewed from one of the pair of connection membrane electrodes 32, of the edges of the connection membrane electrode 32. As a result, the end of the opposite section 62 is also located on the substrate 30.

[ description of operation ]

When a current flows through the protection element 10 of the present embodiment, the fusible body 34 generates heat. When the magnitude of the current becomes equal to or larger than a predetermined magnitude, the fusible body 34 reaches a predetermined temperature. The fusible body 34 that reaches a prescribed temperature melts. When the fusible body 34 melts, the pair of connection film electrodes 32, 32 is cut. In parallel with this, gas is generated due to various causes caused by the melting of the meltable body 34. Examples of causes of gas generation include vaporization of components of the meltable body 34 and heating of the flux 40 by an arc generated by melting of the meltable body 34. The generated gas diffuses toward the surroundings. When the fusible element 34 is blown, the gas is generated, and the components are scattered or the fusible element 34 is blown. They also diffuse to the surroundings. Some of them may be mixed into the gas.

When the gas contacts the opposing section 60 of the extension 42, a portion of the gas flows along the opposing section 60. As a result, the pair of opposing sections 60, 60 guides a part of the gas between the pair of connection membrane electrodes 32, 32 in the substrate 30. The gas directed thereto flows directly into contact with the inner wall of the seal 46. Since the gas contacts the inner wall of the sealing body 46, a part of kinetic energy of the gas becomes energy such as thermal energy. The gas then circulates within the hood 44.

[ Explanation of Effect ]

In the protective element 10 of the present embodiment, the gas reaches the portion where the lead conductor 36 and the connection membrane electrode 32 are connected with a delay. If the arrival is delayed, the possibility that the energy of the gas is taken away as energy such as heat energy by an object around the gas during the delay of the arrival becomes high. When the energy of the gas is taken away, the possibility that the vicinity of the portion where the lead conductor 36 and the connection membrane electrode 32 are connected is damaged by the energy of the gas is reduced. As a result, the protective element 10 is provided in which the possibility of breakage is further suppressed.

In the protective element 10 of the present embodiment, the opposing section 60 extends beyond the linear section 160 at the edge of the connection membrane electrode 32. Thereby, the arrival of the gas is further delayed. Since the arrival is further delayed, the possibility that the vicinity of the portion where the lead conductor 36 and the connection membrane electrode 32 are connected is damaged by the energy of the gas is further reduced.

Also, in the protective member 10 of the present embodiment, the extension 42 has the opposite intermediate portion 62. Thus, the gas flowing toward the opposite section 62 side along the shield 38 among the gases reaches the portion of the connection membrane electrode 32 connected to the lead conductor 36 with a delay as compared with the case where the opposite section 62 is not provided. Due to the delay in arrival, the possibility that the vicinity of the site is damaged by the energy of the gas is reduced.

The pair of opposing sections 60, 60 face each other with a gap therebetween, and serve as flow paths for the gas. The pair of opposing sections 60, 60 extend beyond sections 160, 160 of the edges of the connection membrane electrode 32 where the pair of connection membrane electrodes 32, 32 oppose each other. Thereby, the pair of opposing sections 60, 60 are narrowed at a distance from each other. If the portion is narrowed, the flow velocity of the fluid becomes fast at the portion. As a result, when the flow rate of the fluid increases, the fluid that has passed through the portion is less likely to reach the portion of the connection membrane electrode 32 that is connected to the lead conductor 36. Since the possibility is reduced, the possibility that the vicinity of the portion is damaged by the energy of the gas is reduced.

(description of modification)

The protection element 10 described above is exemplified to embody the technical idea of the present invention. The protective element 10 described above may be variously modified within the scope of the technical idea of the present invention.

For example, the extension portion 42 may be provided only on one of the pair of connection membrane electrodes 32, 32. The extension 42 may not be integral with the shield 38. In the case where the blindfold 38 is provided to both of the pair of connection membrane electrodes 32, 32 and the opposing intermediate portions 60, 60 are provided to each of them, the opposing intermediate portions 60, 60 may not be opposed to each other. The extension 42 may have only the opposing section 60 or only the opposing section 62. The sections 160, 160 that are part of the edges of the pair of connection membrane electrodes 32, 32 and extend along each other may not have a straight shape.

Fig. 4 is an enlarged view of the vicinity of the extension 102 in the protective element according to the modified example of the invention of the above embodiment. The structure of the extension 102 according to the present modification will be described with reference to fig. 4.

The protective element of this variant has other extensions 102, 102 instead of the extensions 42, 42 described above. The extension 102 of the present modification has an opposing section 120 and an opposing section 122. The opposite section 120 is connected to the shield 38. The opposing intermediate portion 120 of the present modification is integral with the shield 38. The opposing section 120 extends at least to a linear section 160 in the edge of the connecting membrane electrode 32. And an opposite intermediate portion 122 is connected to shield 38. The opposite intermediate portion 122 of the present modification is integral with the shutter 38. The opposite section 122 extends at least to the opposite side section 162. The opposite-side section 162 is a section of the edge of the connection membrane electrode 32 on the side opposite to the other side of the pair of connection membrane electrodes 32, 32 when viewed from one of the pair of connection membrane electrodes 32, 32.

The opposing land portion 120 has a wayside formation portion 140 and an occlusion portion 142. The roadside formation portion 140 spreads along the edge of the connection-use membrane electrode 32. As is apparent from fig. 4, the roadside formation portion 140 of the present modification extends along the edge of the connection membrane electrode 32 that extends linearly. The blocking portion 142 blocks the gap between the roadside forming portion 140 and the shutter 38.

In the protection element of the present modification, the wayside formation portion 140 extends in the direction in which the edge of the connection membrane electrode 32 extends. If the wayside formation part 140 expands in this direction, at least a part of the gas generated due to various causes caused by the fusion of the fusible body 34 flows along the wayside formation part 140 in the membrane electrode for connection 32. When the gas thus flows, it is difficult for the gas to access the portion to which the lead conductor 36 is connected. This reduces the possibility that the vicinity of the part is damaged by the energy of the gas. If the possibility of damage to the vicinity is reduced, the possibility of breakage of the protection element of the present modification due to the damage is reduced.

Then, the gas flows along the roadside formation portions 140. If the roadside formation portion 140 expands along the linear section 160 of the edge of the connection-use membrane electrode 32, the gas flows linearly. This increases the possibility that the fluid passes through the vicinity of the connection membrane electrode 32 quickly. If this possibility becomes high, the possibility that the vicinity of the portion of the connection membrane electrode 32 connected to the lead conductor 36 is damaged by the energy of the gas flowing in is reduced.

Claims (6)

1. A protective element having:

a substrate;

a pair of connection membrane electrodes provided on one surface of the substrate;

a fusible body bridged across a pair of the joining membrane electrodes;

a pair of lead conductors connected to the different connection film electrodes;

a shielding member provided between a portion of the connection film electrode connected to the fusible body and a portion connected to the lead conductor; and

a cover covering at least a region from the fusible body to a portion of the pair of lead conductors connected to the connection membrane electrode,

further comprising: and the extension part is connected with the shielding piece and at least extends to the edge of the membrane electrode for connection.

2. The protective element according to claim 1,

a direction from a portion of each of the pair of connection film electrodes connected to the fusible body toward a portion connected to the lead conductor, and a direction in which the fusible body is directed from one of the pair of connection film electrodes toward the other,

a pair of the connection-use membrane electrodes are disposed so as to oppose each other,

the edge of each of the pair of the connection membrane electrodes has a section extending linearly along each other,

the extension portion is connected to the shield and has an opposing section extending beyond the linearly extending section in the edge of the connection membrane electrode.

3. The protective element according to claim 2,

the elongated portion is connected to the shutter, and has, in addition to the opposing section portion, an opposing section portion that at least exceeds a section of an edge of the connecting membrane electrode on a side opposite to the other side of the pair of connecting membrane electrodes when viewed from one of the pair of connecting membrane electrodes.

4. The protective element according to claim 1,

the extension portion has:

a roadside formation portion that extends along an edge of the connection membrane electrode; and

and a blocking portion that blocks a gap between the roadside formation portion and the shield.

5. The protective element according to claim 4,

the edge of the connecting membrane electrode has a section extending in a straight line,

the wayside formation portion extends along a section of the edge of the connection membrane electrode that extends in the straight line.

6. The protective element according to claim 1,

a direction from a site connected with the fusible body in each of the pair of connection film electrodes toward a site connected with the lead conductor intersects with a direction from one of the pair of connection film electrodes toward the other of the pair of fusible bodies,

a pair of the connection-use membrane electrodes are disposed so as to oppose each other,

the edge of each of the pair of the connection membrane electrodes has a section extending linearly along each other,

the shutter is provided on each of a pair of the membrane electrodes for connection,

the extension being associated with each of a pair of the blinders,

the elongate portions associated with each of the pair of shutters are spaced apart to oppose each other.

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