Protective element

Abstract

The protection element (1) is provided with a first fuse element (10), a first terminal (30) and a second terminal (40) which are connected to both ends of the first fuse element (10) in the energization direction, and an insulating housing (50) which accommodates the first fuse element (10) and a part of the first terminal (30) and the second terminal (40). The first fuse element (10) has a first conductor (11) and a first fusible conductor (12) connected in series in the energization direction. The first conductor (11) is provided with a first buffer section (15) that relaxes physical stress. In the insulating housing (50), a first buffer space (51) is formed around the first buffer portion (15). The protective element (1) is further provided with a first filler (71) disposed in the first cushion space (51) so as to surround the first cushion section (15). The insulating housing (50) is configured so as to be close to or in contact with a portion of the first fuse element (10) other than the periphery of the first buffer section (15).

Description

Technical Field

[0001] This invention relates to protective elements.

[0002] This invention claims priority based on Japanese Patent Application No. 2023-124363, filed in Japan on July 31, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] Previously, fuses existed that would melt and break the current path when a current exceeding its rated value flowed through it. Protective components incorporating fuses (fuse elements) are used in a wide range of applications, from home appliances to electric vehicles.

[0004] For example, lithium-ion batteries are used in a wide range of applications, from mobile devices to electric vehicles (EVs) and storage batteries, and are being driven towards higher capacities. Along with the increase in capacity, the voltage of lithium-ion batteries is becoming a high-voltage specification of hundreds of volts, and the current required is also increasing from hundreds of amperes to thousands of amperes.

[0005] The following technologies exist as techniques for creating hot spots in foil-shaped fuse elements by utilizing holes, thickness variations, cuts, etc., to melt the fuse element when an overcurrent occurs.

[0006] For example, Patent Document 1 discloses a fuse in which the thickness of the cut portion of the conductive thin film pattern formed on the insulating substrate is set to be thinner than the thickness of the connecting portion connected in series with the cut portion.

[0007] For example, Patent Documents 2 and 3 disclose fuse elements in which the fusible portion is formed by punching holes through multiple elements arranged in parallel.

[0008] For example, Patent Documents 4 and 5 disclose a fuse in which a pattern of conductive thin film is formed on the surface of an insulating substrate, and the thickness of the cut portion having multiple cut-off slits arranged in parallel is thinner than the thickness of the connecting strip connected in series to the cut portion.

[0009] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 6057413; Patent Document 2: Japanese Patent No. 6199368; Patent document 3: Japanese Patent No. 5952751; Patent document 4: Japanese Patent No. 5116119; Patent document 5: Japanese Patent No. 4998890. Summary of the Invention

[0010] The problem that the invention aims to solve In protective components designed for high-voltage / high-current interruption, arcing during interruption becomes a significant concern. Generally, to suppress arcing, silica sand, known as an arc-extinguishing agent, is placed around the fuse element. Furthermore, with the miniaturization / lower resistance (shorter size) of protective components, the fusible portion of the fuse element is widened or thickened. In this case, molten debris continuously adheres to the surface of the arc-extinguishing agent, forming a conductive path and significantly reducing interruption performance. Additionally, the risk of a decrease in insulation resistance after interruption may increase.

[0011] The present invention was made in view of the above circumstances, and its purpose is to provide a protective element that can suppress arc discharge during disconnection, can cope with high voltage / high current disconnection, and suppress the decrease in insulation resistance after disconnection.

[0012] Solution for solving the problem To address the aforementioned issues, the present invention provides the following means.

[0013] [Solution 1] A protective element comprising: a first fuse element; a first terminal and a second terminal connected to both ends of the first fuse element in the direction of energization; and an insulating housing accommodating a portion of the first terminal and the second terminal and the first fuse element, the first fuse element having a first conductor and a first fusible conductor connected in series along the direction of energization of the first fuse element, the first conductor having a first buffer portion for mitigating physical stress, a first buffer space being formed around the first buffer portion in the insulating housing, the protective element further comprising a first filling material disposed in the first buffer space in a manner surrounding the first buffer portion, and the insulating housing being configured to approach or contact a portion of the first fuse element other than the periphery of the first buffer portion.

[0014] [Solution 2] The protective element described in Solution 1, wherein the first fuse element further comprises a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element, the first conductor being connected to one end of the first fusible conductor, the second conductor being connected to the other end of the first fusible conductor, the first terminal being connected to the first conductor, the second terminal being connected to the second conductor, the second conductor having a second buffer portion to mitigate physical stress, and a second buffer space being formed around the second buffer portion in the insulating housing, the protective element further comprising a second filling material disposed in the second buffer space in a manner that surrounds the second buffer portion.

[0015] [Solution 3] The protective element described in Solution 1 or 2, wherein an element receiving space and an internal pressure buffer space connected to the element receiving space via a leakage hole and / or gap are formed in the aforementioned insulating housing at a location other than the periphery of the aforementioned first buffer portion of the aforementioned first fuse element, and the aforementioned protective element further comprises a third filling material disposed in at least a portion of the aforementioned internal pressure buffer space.

[0016] [Solution 4] The protective element described in Solution 2, wherein each of the aforementioned first conductor and the aforementioned second conductor is a plate-shaped component made of metal, and the aforementioned insulating shell is configured such that it is close to or in contact with the plate-shaped surface portion and back portion outside the periphery of the aforementioned first buffer portion of the aforementioned first conductor and outside the periphery of the aforementioned second buffer portion of the aforementioned second conductor.

[0017] [Solution 5] The protective element described in Solution 2 or 4, wherein each of the aforementioned first conductor and the aforementioned second conductor is made of Ag or Cu, or a metal with Ag or Cu as the main component.

[0018] [Solution 6] Any of the protective elements described in Solutions 1 to 5, wherein the aforementioned first fusible conductor is made of Sn or a metal with Sn as the main component.

[0019] [Solution 7] Any of the protective elements described in Solutions 1 to 6, wherein the aforementioned first fusible conductor is a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer.

[0020] [Solution 8] The protective element described in Solution 7, wherein the aforementioned high-melting-point metal layer is made of Ag or Cu, or a metal with Ag or Cu as the main component, and the aforementioned low-melting-point metal layer is made of Sn or a metal with Sn as the main component.

[0021] [Solution 9] The protective element of Solution 3, wherein the aforementioned insulating housing comprises: a first retaining member having at least the aforementioned first buffer space; a second retaining member having the aforementioned internal pressure buffer space; a third retaining member shielding the open surface of the aforementioned internal pressure buffer space; and a cover inserted from a direction orthogonal to the direction of stacking the aforementioned first retaining member, the aforementioned second retaining member and the aforementioned third retaining member.

[0022] [Solution 10] The protective element described in Solution 2, wherein each of the aforementioned first filler material and the aforementioned second filler material is made of elastic resin.

[0023] [Solution 11] The protective element described in Solution 10, wherein the aforementioned elastic resin is a silicone resin or a photocurable acrylic resin.

[0024] [Solution 12] The protective element described in Solution 3, wherein the aforementioned third filling material comprises at least insulating fibers or silica sand.

[0025] [Solution 13] The protective element described in Solution 12, wherein the aforementioned insulating fiber is ceramic fiber paper.

[0026] [Solution 14] Any of the protective elements described in Solutions 1 to 13, wherein flux is applied to at least one surface of the aforementioned first fusible conductor.

[0027] [Solution 15] Any of the protective elements described in Solutions 1 to 14, wherein the aforementioned insulating housing is made of polyamide resin or fluorinated resin.

[0028] [Solution 16] A protective element comprising: a first fuse element; a first terminal and a second terminal connected to the two ends of the first fuse element in the direction of energization; a heating element; a power supply component connected to the heating element; and an insulating housing accommodating a portion of the first terminal and the second terminal, the first fuse element, the heating element, and a portion of the power supply component. The first fuse element has a first conductor and a first fusible conductor connected in series in the direction of energization of the first fuse element. The first conductor has a first buffer portion for mitigating physical stress. A first buffer space is formed around the first buffer portion in the insulating housing. The protective element further comprises a first filling material disposed in the first buffer space in a manner that surrounds the first buffer portion. The insulating housing is configured to be close to or in contact with a portion of the first fuse element other than the periphery of the first buffer portion.

[0029] [Solution 17] The protective element described in Solution 16, wherein the aforementioned first fuse element further comprises a second conductor connected in series with the aforementioned first fusible conductor along the energizing direction of the aforementioned first fuse element, the aforementioned first conductor being connected to one end of the aforementioned first fusible conductor, the aforementioned second conductor being connected to the other end of the aforementioned first fusible conductor, the aforementioned first terminal being connected to the aforementioned first conductor, the aforementioned second terminal being connected to the aforementioned second conductor, the aforementioned second conductor having a second buffer portion to mitigate physical stress, a second buffer space being formed around the aforementioned second buffer portion in the aforementioned insulating housing, the aforementioned protective element further comprising a second filling material disposed in the aforementioned second buffer space in a manner surrounding the aforementioned second buffer portion.

[0030] [Solution 18] The protective element described in Solution 16 or 17, wherein an element receiving space and an internal pressure buffer space connected to the element receiving space via a leakage hole and / or gap are formed in the aforementioned insulating housing at a location other than the periphery of the aforementioned first buffer portion of the aforementioned first fuse element, and the aforementioned protective element further comprises a third filling material disposed in at least a portion of the aforementioned internal pressure buffer space.

[0031] [Solution 19] The protective element described in Solution 17, wherein each of the first conductor and the second conductor is a plate-shaped component made of metal, and the insulating shell is configured such that it is close to or in contact with the plate-shaped surface portion and back portion outside the periphery of the first buffer portion of the first conductor and outside the periphery of the second buffer portion of the second conductor.

[0032] [Solution 20] The protective element described in Solution 17 or 19, wherein each of the aforementioned first conductor and the aforementioned second conductor is made of Ag or Cu, or a metal with Ag or Cu as the main component.

[0033] [Scheme 21] Any of the protective elements described in Schemes 16 to 20, wherein the aforementioned first fusible conductor is made of Sn or a metal with Sn as the main component.

[0034] [Solution 22] Any of the protective elements described in Solutions 16-21, wherein the aforementioned first fusible conductor is a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer.

[0035] [Solution 23] The protective element described in Solution 22, wherein the aforementioned high-melting-point metal layer is made of Ag or Cu, or a metal with Ag or Cu as the main component, and the aforementioned low-melting-point metal layer is made of Sn or a metal with Sn as the main component.

[0036] [Solution 24] The protective element of Solution 18, wherein the aforementioned insulating housing comprises: a first retaining member having at least the aforementioned first buffer space; a second retaining member having the aforementioned internal pressure buffer space; a third retaining member shielding the open surface of the aforementioned internal pressure buffer space; and a first cover and a second cover, which are respectively inserted from two directions orthogonal to the direction of stacking the aforementioned first retaining member, the aforementioned second retaining member and the aforementioned third retaining member.

[0037] [Solution 25] The protective element of Solution 17, wherein each of the aforementioned first filler material and the aforementioned second filler material is made of elastic resin.

[0038] [Solution 26] The protective element described in Solution 25, wherein the aforementioned elastic resin is a silicone resin or a photocurable acrylic resin.

[0039] [Solution 27] The protective element described in Solution 18, wherein the aforementioned third filling material comprises at least insulating fibers or silica sand.

[0040] [Solution 28] The protective element described in Solution 27, wherein the aforementioned insulating fiber is ceramic fiber paper.

[0041] [Solution 29] Any of the protective elements described in Solutions 16 to 28, wherein flux is applied to at least one surface of the aforementioned first fusible conductor.

[0042] [Solution 30] Any of the protective elements described in Solutions 16 to 29, wherein the aforementioned insulating housing is made of polyamide resin or fluorinated resin.

[0043] [Solution 31] The protective element of Solution 1 includes: a second fuse element, which is configured in parallel with the first fuse element and connected to the first terminal and the second terminal; and an insulating member, which is disposed between the first fuse element and the second fuse element, having a first opposing surface that is close to or in contact with the first fuse element and a second opposing surface that is close to or in contact with the second fuse element, the second fuse element having a third conductor and a second fusible conductor connected in series along the energizing direction of the second fuse element, the third conductor having a third buffer portion, which is disposed in the first buffer space in a manner surrounded by the first filling material to mitigate physical stress, and the insulating shell being configured to be close to or in contact with a portion other than the periphery of the third buffer portion of the second fuse element.

[0044] [Solution 32] The protective element of Solution 31, wherein the first fuse element further comprises a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element, the first conductor being connected to one end of the first fusible conductor, the second conductor being connected to the other end of the first fusible conductor, the first terminal being connected to the first conductor, the second terminal being connected to the second conductor, the second conductor having a second buffer portion to mitigate physical stress, and a second buffer space being formed around the second buffer portion in the insulating housing, the protective element further comprising a second filling material disposed in the second buffer space in a manner surrounding the second buffer portion.

[0045] [Solution 33] The protective element described in Solution 32, wherein the aforementioned second fuse element further comprises a fourth conductor connected in series with the aforementioned second fusible conductor along the energizing direction of the aforementioned second fuse element, the aforementioned third conductor is connected to one end of the aforementioned second fusible conductor, the aforementioned fourth conductor is connected to the other end of the aforementioned second fusible conductor, the aforementioned first terminal is connected to the aforementioned third conductor, the aforementioned second terminal is connected to the aforementioned fourth conductor, and the aforementioned fourth conductor comprises a fourth buffer portion, which is disposed in the aforementioned second buffer space in a manner surrounded by the aforementioned second filling material to mitigate physical stress.

[0046] [Solution 34] Any of the protective elements described in Solutions 31 to 33, wherein a first element receiving space and an internal pressure buffer space connected to the first element receiving space are formed in the aforementioned insulating housing at a location other than the periphery of the aforementioned first buffer portion of the aforementioned first fuse element, and the aforementioned protective element further comprises a third filling material disposed in at least a portion of the aforementioned internal pressure buffer space.

[0047] [Solution 35] The protective element of Solution 34, wherein a second element receiving space is formed in the aforementioned insulating housing, at a location other than the periphery of the aforementioned third buffer portion of the aforementioned second fuse element, and the aforementioned second element receiving space is connected to the aforementioned internal pressure buffer space via the aforementioned leakage hole and / or gap.

[0048] [Solution 36] The protective element of Solution 16 includes: a second fuse element, which is configured in parallel with the first fuse element and connected to the first terminal and the second terminal; and an insulating member, which is disposed between the first fuse element and the second fuse element, having a first opposing surface that is close to or in contact with the first fuse element and a second opposing surface that is close to or in contact with the second fuse element, the second fuse element having a third conductor and a second fusible conductor connected in series along the energizing direction of the second fuse element, the third conductor having a third buffer portion, which is disposed in the first buffer space in a manner surrounded by the first filling material to mitigate physical stress, and the insulating shell being configured to be close to or in contact with a portion other than the periphery of the third buffer portion of the second fuse element.

[0049] [Solution 37] The protective element described in Solution 36, wherein the aforementioned first fuse element further comprises a second conductor connected in series with the aforementioned first fusible conductor along the energizing direction of the aforementioned first fuse element, the aforementioned first conductor being connected to one end of the aforementioned first fusible conductor, the aforementioned second conductor being connected to the other end of the aforementioned first fusible conductor, the aforementioned first terminal being connected to the aforementioned first conductor, the aforementioned second terminal being connected to the aforementioned second conductor, the aforementioned second conductor having a second buffer portion for easing physical stress, a second buffer space being formed around the aforementioned second buffer portion in the aforementioned insulating housing, the aforementioned protective element further comprising a second filling material disposed in the aforementioned second buffer space in a manner surrounding the aforementioned second buffer portion.

[0050] [Solution 38] The protective element described in Solution 37, wherein the aforementioned second fuse element further comprises a fourth conductor connected in series with the aforementioned second fusible conductor along the energizing direction of the aforementioned second fuse element, the aforementioned third conductor is connected to one end of the aforementioned second fusible conductor, the aforementioned fourth conductor is connected to the other end of the aforementioned second fusible conductor, the aforementioned first terminal is connected to the aforementioned third conductor, the aforementioned second terminal is connected to the aforementioned fourth conductor, and the aforementioned fourth conductor comprises a fourth buffer portion, which is disposed in the aforementioned second buffer space in a manner surrounded by the aforementioned second filling material to mitigate physical stress.

[0051] [Solution 39] Any of the protective elements described in Solutions 36 to 38, wherein a first element receiving space and an internal pressure buffer space connected to the first element receiving space are formed in the aforementioned insulating housing at a location other than the periphery of the aforementioned first buffer portion of the aforementioned first fuse element, and the aforementioned protective element further comprises a third filling material disposed in at least a portion of the aforementioned internal pressure buffer space.

[0052] [Solution 40] The protective element of Solution 39, wherein a second element receiving space is formed in the aforementioned insulating housing, at a location other than the periphery of the aforementioned third buffer portion of the aforementioned second fuse element, and the aforementioned second element receiving space is connected to the aforementioned internal pressure buffer space via the aforementioned leakage hole and / or gap.

[0053] [Invention Effects] According to the present invention, a protective element is provided that can suppress arc discharge during disconnection, cope with high voltage / high current disconnection, and suppress the decrease in insulation resistance after disconnection. Attached Figure Description

[0054] Figure 1 This is a diagram showing the protective element of the first embodiment. Figure 2 Section II.

[0055] Figure 2 This is a diagram showing the protective element of the first embodiment. Figure 1 Section II-II.

[0056] Figure 3 This is a side view of the protective element in the first embodiment. Figure 2 III-direction view.

[0057] Figure 4 yes Figure 1 Section IV-IV.

[0058] Figure 5 yes Figure 1 VV cross-section diagram.

[0059] Figure 6 This is a diagram showing the protective element of the second embodiment. Figure 7 Section VI-VI.

[0060] Figure 7 This is a diagram showing the protective element of the second embodiment. Figure 6 Section VII-VII.

[0061] Figure 8 This is a side view of the protective element in the second embodiment. Figure 7 The VIII view.

[0062] Figure 9 yes Figure 6 IX-IX cross-section.

[0063] Figure 10 This diagram illustrates the protective element of the third embodiment, which is equivalent to... Figure 2 Cross-sectional view.

[0064] Figure 11 yes Figure 10 XI-XI cross-sectional view.

[0065] Figure 12 This diagram illustrates the protective element of the fourth embodiment, which is equivalent to... Figure 2 Cross-sectional view. Detailed Implementation

[0066] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In order to facilitate understanding of the features, the drawings used in the following description sometimes show enlarged portions of the features, and sometimes the dimensional ratios of the constituent elements differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are examples, and the present invention is not limited to these; appropriate modifications can be made within the scope of achieving the effects of the present invention.

[0067] (First Implementation) For the protective element of one embodiment of the present invention, refer to Figures 1 to 5 This will be explained. The protection element in this embodiment forms part of a high-voltage, high-current (100V / 100A or more) circuit, for example, using a lithium-ion secondary battery. The protection element is, for example, mounted in an electric vehicle (EV).

[0068] Refer to together Figures 1 to 5The protective element 1 includes: a first fuse element 10; a first terminal 30 and a second terminal 40 connected to the two ends of the first fuse element 10 in the direction of energization; and an insulating housing 50 that houses a portion of the first terminal 30 and the second terminal 40 and the first fuse element 10. The first terminal 30 and the second terminal 40 are arranged away from each other in a predetermined direction. Each of the first terminal 30 and the second terminal 40 is plate-shaped.

[0069] The protection element 1, as a mechanism for cutting off the current path, has an overcurrent cut-off element that, when an overcurrent (above a predetermined value) exceeding the rated current flows through the first fuse element 10, melts the first fuse element 10 and cuts off the current path.

[0070] The following sections will sometimes use an XYZ orthogonal coordinate system (three-dimensional orthogonal coordinate system) in the figures to explain the components.

[0071] The aforementioned predetermined direction in which the first terminal 30 and the second terminal 40 are arranged side by side is called the front-back direction. In each diagram, the front-back direction corresponds to the X-axis direction. Within the X-axis direction, the direction from the second terminal 40 towards the first terminal 30 (-X side) is called the front side, and the direction from the first terminal 30 towards the second terminal 40 (+X side) is called the rear side. Furthermore, the front-back direction is the direction connecting the first terminal 30 and the second terminal 40, and it is also the direction in which current flows when the protection element 1 is used; therefore, it can also be referred to as the energizing direction.

[0072] The direction in which the surfaces of the first terminal 30 and the second terminal 40 face is called the up-down direction. The up-down direction is orthogonal to the front-back direction and corresponds to the Z-axis direction in the diagrams. In the up-down direction, the upper side corresponds to the +Z side, and the lower side corresponds to the -Z side.

[0073] The direction orthogonal to the front-back and up-down directions is called the left-right direction. In the diagrams, the left-right direction corresponds to the Y-axis. Within the left-right direction, the left side corresponds to the -Y side, and the right side corresponds to the +Y side. Specifically, the -Y side is the left side when viewing protective element 1 from the rear (+X side), and the +Y side is the right side when viewing protective element 1 from the rear. Alternatively, the left-right direction can also be referred to as the width direction. In this case, for example, one side of the width direction corresponds to the -Y side, and the other side corresponds to the +Y side.

[0074] Furthermore, in this embodiment, front, rear, upper, lower, left, and right are convenient names used to easily explain the relative positional relationships of each component. The actual configuration relationship may also be a configuration relationship other than that indicated by these names.

[0075] (First terminal, second terminal) Each of the first terminal 30 and the second terminal 40 is plate-shaped, extending in a plane direction perpendicular to the vertical direction (XY plane direction). In the example shown in the figure, each of the first terminal 30 and the second terminal 40 is approximately quadrilateral plate-shaped. The first terminal 30 and the second terminal 40 are arranged far apart from each other in the front-back direction.

[0076] The rear end of the first terminal 30 is connected to the front end of the first fuse element 10. The front portion of the first terminal 30 protrudes forward from the insulating housing 50 and is exposed outside the insulating housing 50.

[0077] The front end of the second terminal 40 is connected to the rear end of the first fuse element 10. The rear portion of the second terminal 40 protrudes rearward from the insulating housing 50 and is exposed outside the insulating housing 50.

[0078] The first terminal 30 includes: a terminal body 31 having an external terminal hole 32; a conductor connection portion 33 connected to the front end of the first fuse element 10; and a locking claw 34 locking onto the terminal locking portion 58 of the insulating housing 50.

[0079] The terminal body 31 is a quadrilateral plate that extends along the front-to-back direction. The rear part of the terminal body 31 is disposed between the terminal mounting surface 57 and the terminal pressing surface 59 at the front of the insulating housing 50, and is sandwiched between the terminal mounting surface 57 and the terminal pressing surface 59.

[0080] The external terminal hole 32 is a circular hole that runs through the terminal body 31 in the vertical direction.

[0081] The conductor connection portion 33 is disposed at the rear end of the first terminal 30 and extends in the left-right direction. For example, the front end of the first fuse element 10 is connected to the conductor connection portion 33 by welding or the like.

[0082] The locking claw 34 protrudes further to the left and right than the terminal body 31. Specifically, the locking claw 34 is provided at each of the left and right ends of the conductor connection portion 33.

[0083] The second terminal 40 includes: a terminal body 41 having an external terminal hole 42; a conductor connection portion 43 connected to the rear end of the first fuse element 10; and a locking claw 44 locking onto the terminal locking portion 58 of the insulating housing 50.

[0084] The terminal body 41 is a quadrilateral plate that extends along the front-to-back direction. The front part of the terminal body 41 is disposed between the terminal mounting surface 57 and the terminal pressing surface 59 at the rear of the insulating housing 50, and is sandwiched between the terminal mounting surface 57 and the terminal pressing surface 59.

[0085] The external terminal hole 42 is a circular hole that runs through the terminal body 41 in the vertical direction.

[0086] The conductor connection portion 43 is disposed at the front end of the second terminal 40 and extends in the left-right direction. For example, the rear end of the first fuse element 10 is connected to the conductor connection portion 43 by welding or the like.

[0087] The locking claw 44 protrudes further to the left and right than the terminal body 41. Specifically, the locking claw 44 is provided at each of the left and right ends of the conductor connection portion 43.

[0088] For example, one of the pair of external terminal holes 32 and 42 is connected to the power supply side, and the other is connected to the load side. Furthermore, not limited to the above, the external terminal holes 32 and 42 can also be connected to the internal power path of the load. For example, the connection scheme of the external terminal holes 32 and 42 can be changed accordingly based on design specifications.

[0089] For example, each of the first terminal 30 and the second terminal 40 is a metal product made of copper, brass, nickel, etc. From the viewpoint of increasing rigidity, brass is preferred for the first terminal 30 and the second terminal 40, while copper is preferred from the viewpoint of reducing resistance. When using copper, it is preferable to perform rust-preventive treatments such as nickel plating, silver plating, or tin plating on the surface. The first terminal 30 and the second terminal 40 can be made of the same material or different materials. For example, the materials of each of the first terminal 30 and the second terminal 40 can be changed according to the design specifications.

[0090] (First fuse element) The first fuse element 10 is composed of a metal plate-shaped component, sheet-shaped component, or metal foil, etc. In the example shown in the figure, only one first fuse element 10 is provided, but it is not limited to this. For example, two first fuse elements 10 may be arranged side by side in the vertical direction, or more than three may be arranged side by side. For example, the arrangement of the first fuse elements 10 can be changed accordingly according to the design specifications.

[0091] The first fuse element 10 has a first conductor 11, a first fusible conductor 127, and a second conductor 13 connected in series along the direction of current flow. For example, the first fusible conductor 127 is made of a material with a melting temperature lower than that of the first conductor 11 and the second conductor 13. For example, the resistivity of the first fusible conductor 127 is higher than that of the first conductor 11 and the second conductor 13. The first fusible conductor 127 functions as the fusible part of the first fuse element 10 when an overcurrent is interrupted.

[0092] The first fusible conductor 12 is plate-shaped, sheet-shaped, or foil-shaped, extending along a plane direction perpendicular to the vertical direction (XY plane direction). In the example shown in the figure, viewed from the vertical direction, the first fusible conductor 12 is a quadrilateral plate-shaped structure with a dimension larger in the horizontal direction than in the front-back direction. The first fusible conductor 12 is disposed at the center of the first fuse element 10 in the front-back direction. In this embodiment, flux 75 is applied to at least one surface of the first fusible conductor 12.

[0093] For example, the first fusible conductor 12 is made of Sn or a metal with Sn as its main component. Although not shown, the first fusible conductor 12 may also be a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer. This laminate may also be configured to have one or more low-melting-point metal layers, two or more high-melting-point metal layers, with the low-melting-point metal layers disposed between the high-melting-point metal layers. This laminate may also be formed, for example, by coating the low-melting-point metal layers with a high-melting-point metal layer coating.

[0094] For example, the high-melting-point metal layer of the above-mentioned laminate is made of Ag (silver) or Cu (copper), or a metal with Ag or Cu as the main component. The high-melting-point metal layer of the above-mentioned laminate only needs to contain Ag or Cu; it can be Ag monomer, Cu monomer, Ag alloy, or Cu alloy. Ag alloy is the alloy with the highest Ag content among the metals it contains, and Cu alloy is the alloy with the highest Cu content among the metals it contains.

[0095] For example, the low-melting-point metal layer of the aforementioned laminate is made of Sn or a metal with Sn as its main component. The low-melting-point metal layer of the aforementioned laminate only needs to contain Sn; it can be Sn monomer or Sn alloy. Sn alloy is an alloy with Sn as its main component. Sn alloy is the alloy in which the Sn content is the highest among the metals contained in the alloy. Examples of Sn alloys include Sn-Bi alloy, In-Sn alloy, and Sn-Ag-Cu alloy.

[0096] Furthermore, the aforementioned laminate can also be composed of two layers: a low-melting-point metal layer and a high-melting-point metal layer. Alternatively, the aforementioned laminate can also be composed of three or more layers: having two or more high-melting-point metal layers, having one or more low-melting-point metal layers, with the low-melting-point metal layers disposed between the high-melting-point metal layers.

[0097] Alternatively, the first fusible conductor 12 may also be composed of a monolayer containing a low-melting-point metal layer of Sn.

[0098] Each of the first conductor 11 and the second conductor 13 is plate-shaped, sheet-shaped, or foil-shaped. In this embodiment, each of the first conductor 11 and the second conductor 13 is a plate-shaped component made of metal. In the example shown in the figure, viewed from the top-bottom direction, each of the first conductor 11 and the second conductor 13 is a roughly quadrilateral plate-shaped component with a dimension shorter in the left-right direction than in the front-back direction. In this embodiment, each of the first conductor 11 and the second conductor 13 is made of Ag or Cu, or a metal with Ag or Cu as the main component. When using copper, it is preferable to perform rust-preventive treatment such as nickel plating, silver plating, or tin plating on the surface.

[0099] The first conductor 11, the first fusible conductor 12, and the second conductor 13 are connected in series in this order to form the energizing path of the first fuse element 10. Each of the first conductor 11 and the second conductor 13 is connected to the end of the first fusible conductor 12 along the energizing direction of the current flowing through the first fuse element 10 (which corresponds to a roughly front-to-back direction in the example shown in the figure).

[0100] The first conductor 11 is connected to one end of the first fusible conductor 12. In the example shown in the figure, the rear end of the first conductor 11 is fixed to the front end of the first fusible conductor 12. That is, the lower surface of the rear end of the first conductor 11 is connected to the upper surface of the front end of the first fusible conductor 12.

[0101] The second conductor 13 is connected to the other end of the first fusible conductor 12. In the example shown in the figure, the front end of the second conductor 13 is fixed to the rear end of the first fusible conductor 12. That is, the lower surface of the front end of the second conductor 13 is connected to the upper surface of the rear end of the first fusible conductor 12.

[0102] The first soluble conductor 12 is disposed on the lower surface side of the first conductor 11 and the second conductor 13, and is erected between them.

[0103] Furthermore, the vertical relationship between the first fusible conductor 12 and the first conductor 11 and the second conductor 13 is not limited, and the first fusible conductor 12 may also be disposed on the upper surface side of the first conductor 11 and the second conductor 13.

[0104] The first terminal 30 is connected to the first conductor 11. In the example shown in the figure, the rear end of the first terminal 30 is fixed to the front end of the first conductor 11. That is, the lower surface of the rear end of the first terminal 30 is connected to the upper surface of the front end of the first conductor 11.

[0105] The second terminal 40 is connected to the second conductor 13. In the example shown in the figure, the front end of the second terminal 40 is fixed to the rear end of the second conductor 13. That is, the lower surface of the front end of the second terminal 40 is connected to the upper surface of the rear end of the second conductor 13.

[0106] Furthermore, the vertical relationship between the first terminal 30 and the first conductor 11 and the second terminal 40 and the second conductor 13 is not limited. The upper surface of the rear end of the first terminal 30 and the lower surface of the front end of the first conductor 11 can also be connected to each other, and the upper surface of the front end of the second terminal 40 and the lower surface of the rear end of the second conductor 13 can also be connected to each other.

[0107] The first conductor 11 includes an inner plate portion 11A connected to the first fusible conductor 12 and a first buffer portion 15 for mitigating physical stress.

[0108] The inner plate portion 11A is a plate-shaped portion that extends along a plane direction perpendicular to the vertical direction (XY plane direction). The rear end of the inner plate portion 11A is connected to the front end of the first fusible conductor 12 by welding or the like.

[0109] The first buffer portion 15 is disposed between the front end of the inner side plate portion 11A and the rear end of the first terminal 30. The first buffer portion 15 includes: a first extension portion 15A extending downward from the front end of the inner side plate portion 11A, a second extension portion 15B extending forward from the lower end of the first extension portion 15A, a third extension portion 15C extending upward from the front end of the second extension portion 15B, and a fourth extension portion 15D extending forward from the upper end of the third extension portion 15C. The upper surface of the fourth extension portion 15D is connected to the lower surface of the rear end (conductor connection portion 33) of the first terminal 30. For example, the fourth extension portion 15D is connected to the conductor connection portion 33 of the first terminal 30 by welding or the like.

[0110] In the example shown, the first buffer portion 15 is a curved shape that convexes downwards. In other words, the first buffer portion 15 appears as a cap shape protruding downwards when viewed from the left-right direction. Furthermore, the first buffer portion 15 is not limited to the above; it can also be a curved shape that convexes upwards. For example, the first buffer portion 15 can also appear as a crank shape when viewed from the left-right direction. For example, the shape of the first buffer portion 15 can be changed accordingly based on design specifications.

[0111] The second conductor 13 includes an inner plate portion 13A connected to the first fusible conductor 12 and a second buffer portion 16 for mitigating physical stress.

[0112] The inner plate portion 13A is a plate-shaped portion that extends along a plane direction perpendicular to the vertical direction (XY plane direction). The front end of the inner plate portion 13A is connected to the rear end of the first fusible conductor 12 by welding or the like.

[0113] The second buffer portion 16 is disposed between the rear end of the inner side plate portion 13A and the front end of the second terminal 40. The second buffer portion 16 includes: a first extension portion 16A extending downward from the rear end of the inner side plate portion 13A; a second extension portion 16B extending rearward from the lower end of the first extension portion 16A; a third extension portion 16C extending upward from the rear end of the second extension portion 16B; and a fourth extension portion 16D extending rearward from the upper end of the third extension portion 16C. The upper surface of the fourth extension portion 16D is connected to the lower surface of the rear end of the second terminal 40 (conductor connection portion 43). For example, the fourth extension portion 16D is connected to the conductor connection portion 43 of the second terminal 40 by welding or the like.

[0114] In the example shown, the second buffer portion 16 has a downward-convex curved shape. In other words, the second buffer portion 16 appears as a downward-protruding cap shape when viewed from the left-right direction. Furthermore, the second buffer portion 16 is not limited to the above; it can also be a downward-convex curved shape. For example, the second buffer portion 16 can also appear as a crank shape when viewed from the left-right direction. For example, the shape of the second buffer portion 16 can be changed accordingly according to design specifications.

[0115] (Insulating housing) Regarding the insulating housing 50, its overall shape is a column extending in the front-to-back direction. Within the insulating housing 50, a first buffer space 51 is formed around the periphery of the first buffer portion 15, a second buffer space 52 is formed around the periphery of the second buffer portion 16, an element receiving space 53 is formed at a location other than the periphery of the first buffer portion 15 and the periphery of the second buffer portion 16 of the first fuse element 10, and an internal pressure buffer space 55 is formed communicating with the element receiving space 53 via a leakage hole and / or gap 54. The insulating housing 50 is configured to be close to or in contact with the locations of the first fuse element 10 other than the periphery of the first buffer portion 15 and the periphery of the second buffer portion 16.

[0116] The insulating housing 50 includes: a first retaining member 50A, which forms at least a first buffer space 51; a second retaining member 50B, which forms an internal pressure buffer space 55; a third retaining member 50C, which covers the open surface 56 of the internal pressure buffer space 55; and a cover 50D, which is inserted from a direction orthogonal to the direction of stacking the first retaining member 50A, the second retaining member 50B and the third retaining member 50C.

[0117] In addition, the first buffer space 51 may also be formed in the second retaining member 50B instead of the first retaining member 50A.

[0118] The first retaining member 50A is disposed at the lowest of the three retaining members. The first retaining member 50A is disposed below the first terminal 30, the second terminal 40 and the first fuse element 10. The first retaining member 50A includes a terminal mounting surface 57, a terminal locking portion 58 and a conductor opposing recess 60.

[0119] The terminal mounting surface 57 is concave, recessed downward from the upper surface of the first retaining member 50A. The bottom surface of the terminal mounting surface 57 is planar, extending upwards along a plane direction (XY plane direction) perpendicular to the vertical direction. A pair of terminal mounting surfaces 57 are provided on the first retaining member 50A. The pair of terminal mounting surfaces 57 are disposed at both ends of the first retaining member 50A in the front-rear direction.

[0120] A terminal locking portion 58 is disposed on a side wall of the first retaining member 50A, which is vertically disposed on the outer portion in the left-right direction. The terminal locking portion 58 is a groove-shaped portion extending in the vertical direction (in other words, a recessed portion extending outward in the left-right direction). The terminal locking portion 58 is a wall surface that opens inward in the left-right direction along the upper surface of the first retaining member 50A and the aforementioned side wall. A pair of terminal locking portions 58 are disposed at each end of the first retaining member 50A in the front-rear direction (i.e., a total of four).

[0121] The conductor-opposing recess 60 is a recessed portion extending downward from the central side of the first fusible element 10 in the front-rear direction on the upper surface of the first holding member 50A. The conductor-opposing recess 60 is a generally quadrilateral hole opening upwards. The bottom surface of the conductor-opposing recess 60 is a planar surface facing upwards, extending along a plane direction perpendicular to the vertical direction (XY plane direction). The bottom surface of the conductor-opposing recess 60 opposes the lower surface of the first fusible conductor 12. The conductor-opposing recess 60 is disposed on the central side in the front-rear direction of the first holding member 50A. The front-rear dimension of the conductor-opposing recess 60 is larger than the front-rear dimension of the first fusible conductor 12.

[0122] In addition, the conductor-opposing recess 60 may also be formed on the side of the second holding member 50B facing the first fuse element 10.

[0123] The second retaining member 50B is disposed at the central portion of the three retaining members in the vertical direction. The second retaining member 50B is disposed above the first terminal 30, the second terminal 40, and the first fuse element 10. The upper surface of the second retaining member 50B forms the open surface 56 of the internal pressure buffer space 55. The second retaining member 50B has a terminal pressing surface 59.

[0124] The terminal pressing surface 59 is concave, extending upward from the lower surface of the second retaining member 50B. The bottom surface of the terminal pressing surface 59 is planar, extending downward along a plane direction perpendicular to the vertical direction (XY plane direction). A pair of terminal pressing surfaces 59 are provided on the second retaining member 50B. The pair of terminal pressing surfaces 59 are disposed at both ends of the second retaining member 50B in the front-rear direction.

[0125] In addition, the terminal pressing surface 59 may also be formed on the side of the first retaining member 50A facing the first terminal 30 and the second terminal 40.

[0126] The third retaining member 50C is disposed at the uppermost of the three retaining members. The third retaining member 50C has a shape that extends along a surface direction perpendicular to the vertical direction. The lower surface of the third retaining member 50C is planar along the upper surface (open surface 56) of the second retaining member 50B.

[0127] The cover 50D is a cylindrical shape extending in the front-to-back direction. In the example shown in the figure, the cover 50D is a cylindrical shape with an opening in the front-to-back direction. Three retaining parts 50A, 50B, and 50C are housed within the cover 50D in a side-by-side arrangement in the vertical direction. The cover 50D holds the three retaining parts 50A, 50B, and 50C in a fixed state, such as by adhesive bonding.

[0128] When the first retaining member 50A and the second retaining member 50B are combined, a first buffer space 51, a second buffer space 52, and an element receiving space 53 are formed between the first retaining member 50A and the second retaining member 50B. The first fuse element 10 is received in the element receiving space 53.

[0129] A portion of the upper surface of the first retaining member 50A (a portion of the surface facing the element receiving space 53) is configured such that it approaches or contacts the lower surface of the portion other than the periphery of the first buffer portion 15 and the periphery of the second buffer portion 16 of the first fuse element 10. A portion of the lower surface of the second retaining member 50B (a portion of the surface facing the element receiving space 53) is configured such that it approaches or contacts the upper surface of the portion other than the periphery of the first buffer portion 15 and the periphery of the second buffer portion 16 of the first fuse element 10.

[0130] Each of the first buffer space 51 and the second buffer space 52 is formed between the inner wall surface of a recess that extends downward from the upper surface of the first retaining member 50A and the lower surface of the second retaining member 50B. Each of the first buffer space 51 and the second buffer space 52 is a cuboid elongated in the left-right direction when viewed vertically. The first buffer space 51 is formed on the front end side of the first retaining member 50A. The first buffer space 51 is disposed between the rear end of the terminal mounting surface 57 on the front side of the first retaining member 50A and a portion of the front-facing surface of the component receiving space 53. The second buffer space 52 is formed on the rear end side of the first retaining member 50A. The second buffer space 52 is disposed between the front end of the terminal mounting surface 57 on the rear side of the first retaining member 50A and a portion of the rear-facing surface of the component receiving space 53.

[0131] When the second retaining member 50B and the third retaining member 50C are combined, an internal pressure buffer space 55 is formed between the second retaining member 50B and the third retaining member 50C. The internal pressure buffer space 55 is a generally rectangular parallelepiped space that connects to the element receiving space 53 via a leakage hole and / or gap 54. For example, the vertical dimension of the internal pressure buffer space 55 is more than 1 / 3 and less than 1 / 2 of the vertical dimension (outer height) of the entire protective element 1. The internal pressure buffer space 55 has the function of suppressing the rapid rise in internal pressure of the protective element 1 caused by the gas generated by the arc discharge when the first fuse element 10 melts.

[0132] In the example shown in the figure, four leakage holes and / or gaps 54 are arranged at intervals along the front-to-back direction, and a pair are arranged along the left-to-right direction. The leakage holes and / or gaps 54 extend in a straight line along the vertical direction. For example, the opening area of ​​the leakage holes and / or gaps 54 (the cross-sectional area when the leakage holes and / or gaps 54 are cut off by a plane orthogonal to the vertical direction) is less than 20% of the length of the energized direction of the area where the insulating housing 50 is close to or in contact with the first fuse element 10, and there is no restriction outside the area where the insulating housing 50 is close to or in contact with the first fuse element 10. Furthermore, the configuration of the leakage holes and / or gaps 54 (number, placement, shape, opening area, etc.) is not limited to the above and can be changed accordingly according to the design specifications.

[0133] For example, the cover 50D and the retaining components 50A, 50B, and 50C are preferably made of a material with a leakage current resistance index (CTI) of 500V or higher. The leakage current resistance index (CTI) can be determined by testing based on IEC 60112.

[0134] Resin materials can be used as the materials for the cover 50D and the retaining components 50A, 50B, and 50C. Resin materials have a lower heat capacity and a lower melting point than ceramic materials. Therefore, if resin materials are used as the retaining components, they have the characteristics of reducing arc discharge caused by vaporization cooling (ablation) and are preferred because when molten metal particles adhere to the retaining components, the surface of the retaining components deforms or the deposits agglomerate, making the metal particles sparse and difficult to form conductive pathways.

[0135] As the resin material, polyamide resins or fluorinated resins can be used, for example. In this embodiment, the insulating shell 50 is made of a polyamide resin or a fluorinated resin. The polyamide resin can also be an aliphatic polyamide or a semi-aromatic polyamide. Examples of aliphatic polyamides include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of semi-aromatic polyamides include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. Examples of fluorinated resins include polytetrafluoroethylene. In addition, polyamide resins and fluorinated resins have high heat resistance and are difficult to burn. In particular, aliphatic polyamides are difficult to generate graphite even when burned. Therefore, by using an aliphatic polyamide to form the cap 50D and each retaining component, it is possible to more reliably prevent the formation of new current paths due to graphite generated by the arc discharge when the first fuse element 10 melts.

[0136] (First filler material, second filler material) The protective element 1 further includes a first filler material 71 disposed in the first buffer space 51 to surround the first buffer portion 15, and a second filler material 72 disposed in the second buffer space 52 to surround the second buffer portion 16. In this embodiment, each of the first filler material 71 and the second filler material 72 is made of an elastic resin. The elastic resin is a silicone resin or a photocurable acrylic resin.

[0137] Furthermore, the first filler material 71 and the second filler material 72 are not limited to the aforementioned elastic resin, but may also be silicone oil. For example, the first filler material 71 and the second filler material 72 are not limited to solids, but may also be liquids or gels or other fluid materials. For example, the first filler material 71 and the second filler material 72 need only have the function of maintaining the cushioning effect of each buffer portion while simultaneously venting gas from each buffer space. For example, the first filler material 71 and the second filler material 72 may be the same as each other, or they may be different from each other. For example, the design of the first filler material 71 and the second filler material 72 can be modified accordingly based on the design specifications.

[0138] In the example shown in the figure, filler materials 71 and 72 are filled into buffer spaces 51 and 52, respectively. For example, firstly, before mounting the second retaining member 50B onto the first retaining member 50A, filler materials 71 and 72 are placed into buffer spaces 51 and 52, respectively. Subsequently, by installing the second retaining member 50B onto the first retaining member 50A, filler materials 71 and 72 can be filled into buffer spaces 51 and 52, respectively.

[0139] Furthermore, the filling materials 71 and 72 are not limited to filling the buffer spaces 51 and 52 completely without gaps, but may also be filled in a portion of the buffer spaces 51 and 52 with gaps between them. For example, the filling materials 71 and 72 may be disposed in at least a portion of the buffer spaces 51 and 52, respectively, in a manner that at least surrounds the buffer portions 15 and 16.

[0140] (Third filling material) The protective element 1 also includes a third filling material 73 disposed in at least a portion of the internal pressure buffer space 55. The third filling material 73, for example, functions to filter and simultaneously cool metallic gases, and to rapidly and safely extinguish arc discharges generated by arc discharges occurring in the portion of a circuit to be cut off when an excessive current is flowing through it. In this embodiment, the third filling material 73 comprises at least insulating fibers or silica sand.

[0141] The insulating fiber is ceramic fiber paper. Although not shown, multiple ceramic fiber papers can be stacked in the internal pressure buffer space 55. Furthermore, the third filling material 73 is not limited to the aforementioned insulating fiber and can be other fiber materials. Examples of fiber materials include ceramic materials such as SiO2, MgO, Al2O3, and ZrO2, or plastic materials such as nylon and PMMA. Moreover, the fiber material options are not limited to those described above and can be varied according to design specifications.

[0142] Silica sand is granular SiO2 (quartz glass). It is sand primarily composed of quartz grains. Specifically, silica sand is white, coarse-grained sand that contains a particularly large amount of quartz grains in sandy deposits or weathering products mainly composed of silicates.

[0143] Furthermore, the third filler material 73 is not limited to the above and can be made of various materials. For example, the third filler material 73 can also be a spherical component (e.g., ceramic beads or ceramic balls) formed from ceramic materials such as quartz glass, alumina, or zirconium oxide. For example, the third filler material 73 can also be a porous component (e.g., porous ceramic) formed from ceramic materials such as quartz glass, alumina, or zirconium oxide. For example, the third filler material 73 can also be a spherical component (e.g., plastic beads or plastic balls) formed from plastic materials such as nylon or PMMA (acrylic resin). For example, the third filler material 73 can also be a porous component (e.g., porous plastic) formed from plastic materials such as nylon or PMMA. For example, the third filler material 73 can also be formed from sheet-like components, or can be in the shape of wool, plates, blocks, etc. For example, the third filler material 73 can also be a plate-like component (e.g., plate ceramic) formed from ceramic materials such as quartz glass, alumina, or zirconium oxide. For example, the third filler material 73 can be silicone. Silicone is an inorganic polymer with silicon (Si) and oxygen (O) bonds arranged in repeated parallel rows as the main chain. For example, the scheme for the third filler material 73 can be changed accordingly based on the design specifications.

[0144] In the example shown in the figure, the third filler material 73 fills the internal pressure buffer space 55 inside the protective element 1. A portion of the third filler material 73 is in contact with the bottom surface of the recess forming the internal pressure buffer space 55 in the second retaining member 50B located above the first fuse element 10. For example, firstly, the third filler material 73 is placed in the internal pressure buffer space 55 before the third retaining member 50C (corresponding to the cover member constituting the insulating housing 50) is mounted on the second retaining member 50B. Subsequently, by mounting the third retaining member 50C to the second retaining member 50B, the third filler material 73 can be filled into the internal pressure buffer space 55.

[0145] Furthermore, the third filling material 73 is not limited to filling the internal pressure buffer space 55 completely without gaps, but may also be filled in a portion of the internal pressure buffer space 55 with gaps. For example, the third filling material 73 may be disposed in at least a portion of the internal pressure buffer space 55 and in contact with the bottom surface of the recess forming the internal pressure buffer space 55.

[0146] Furthermore, the orientation of the protective element 1 is not limited to being arranged vertically along the direction of gravity; it can also be arranged perpendicularly to the direction of gravity. For example, when the third filling material 73 fills the internal pressure buffer space 55 without gaps, even if the protective element 1 is arranged at an angle relative to the direction of gravity, it will still be in contact with the bottom surface of the recess forming the internal pressure buffer space 55. For example, the configuration of the protective element 1 can be changed accordingly based on the design specifications.

[0147] (Effects of this implementation method) The protective element 1 of this embodiment described above includes: a first fuse element 10; a first terminal 30 and a second terminal 40 connected to both ends of the first fuse element 10 in the direction of current flow; and an insulating housing 50 that houses a portion of the first terminal 30 and the second terminal 40 and the first fuse element 10. The first fuse element 10 has a first conductor 11 and a first fusible conductor 12 connected in series in the direction of current flow. The first conductor 11 has a first buffer portion 15 to mitigate physical stress. In the insulating housing 50, a first buffer space 51 is formed around the first buffer portion 15. The protective element 1 also includes a first filling material 71 disposed in the first buffer space 51 to surround the first buffer portion 15. The insulating housing 50 is configured to be close to or in contact with a portion of the first buffer portion 15 of the first fuse element 10 other than its periphery.

[0148] According to this configuration, the space formed between the first buffer portion 15 of the first fuse element 10 and the insulating housing 50 is narrowed, except for the periphery of the first buffer portion 15. Furthermore, the first buffer portion 15 of the first fuse element 10 is surrounded by a first filling material 71. Therefore, gas, which is one of the sources of arc discharge generated during overcurrent interruption, can be effectively expelled from the periphery of the first fuse element 10. This suppresses plasma generated by the ionization of gas, which is one of the sources of arc discharge, and thus suppresses arc discharge. Furthermore, it is not necessary to fill the periphery of the first fuse element 10 with silica sand, called an arc-extinguishing agent, to suppress arc discharge. Therefore, the problem of molten debris continuously adhering to the surface of the arc-extinguishing agent (resulting in reduced interruption characteristics or decreased insulation resistance after interruption) does not occur. Therefore, it can provide a protective element 1 that can suppress arc discharge during interruption, cope with high-voltage / high-current interruption, and suppress the decrease in insulation resistance after interruption.

[0149] Furthermore, the first buffer portion 15 of the first fuse element 10 mitigates physical stress, thereby alleviating the expansion and contraction caused by the thermal expansion difference between the first fuse element 10 and the insulating housing 50. Therefore, the reliability of the protection element 1 based on temperature cycling can be ensured. Thus, suppressing arc discharge and mitigating the thermal expansion / contraction stress of the first fuse element 10 accompanying temperature cycling of the protection element 1 can coexist.

[0150] In this embodiment, the first fuse element 10 further includes a second conductor 13 connected in series with the first fusible conductor 12 along the energizing direction. The first conductor 11 is connected to one end of the first fusible conductor 12. The second conductor 13 is connected to the other end of the first fusible conductor 12. A first terminal 30 is connected to the first conductor 11. A second terminal 40 is connected to the second conductor 13. The second conductor 13 has a second buffer portion 16 for mitigating physical stress. A second buffer space 52 is formed around the second buffer portion 16 in the insulating housing 50. The protective element 1 further includes a second filling material 72 disposed in the second buffer space 52 to surround the second buffer portion 16.

[0151] According to this configuration, the second buffer portion 16 of the first fuse element 10 is surrounded by the second filling material 72, thus effectively eliminating gas, which is one of the sources of arc discharge generated during overcurrent interruption, around the first fuse element 10. This suppresses plasma generated by gas ionization, which is one of the sources of arc discharge, thereby suppressing arc discharge. Furthermore, the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10 alleviate physical stress, thus more effectively mitigating expansion and contraction caused by the thermal expansion difference between the first fuse element 10 and the insulating shell 50.

[0152] In this embodiment, an element receiving space 53 and an internal pressure buffer space 55 are formed in the insulating housing 50 at a location other than the periphery of the first buffer portion 15 of the first fuse element 10. The protective element 1 also includes a third filling material 73 disposed in at least a portion of the internal pressure buffer space 55.

[0153] According to this configuration, the occurrence of arc discharge can be suppressed by the insulating shell 50, and at the same time, the rapid rise in internal pressure of the protective element 1 caused by molten debris entering the internal pressure buffer space 55 can be effectively suppressed by the third filling material 73. Therefore, when the first fuse element 10 melts, large-scale arc discharge can be suppressed.

[0154] In this embodiment, each of the first conductor 11 and the second conductor 13 is a plate-shaped component made of metal. The insulating housing 50 is configured such that its plate-shaped surface portion and back portion are close to or in contact with the periphery of the first buffer portion 15 of the first conductor 11 and the periphery of the second buffer portion 16 of the second conductor 13.

[0155] According to this configuration, the first buffer portion 15 of the first conductor 11 and the second buffer portion 16 of the second conductor 13 can be formed by bending. For example, the first buffer portion 15 and the second buffer portion 16 can be easily formed by bending (stamping). Furthermore, arc discharge can be suppressed on the plate-shaped surface and back surfaces outside the periphery of the first buffer portion 15 of the first conductor 11 and outside the periphery of the second buffer portion 16 of the second conductor 13.

[0156] In this embodiment, each of the first conductor 11 and the second conductor 13 is made of Ag or Cu, or a metal with Ag or Cu as the main component.

[0157] According to this configuration, compared to the case where each of the first conductor 11 and the second conductor 13 is a laminate containing a high-melting-point metal layer and a low-melting-point metal layer, the resistivity is more easily reduced. Therefore, the thickness of each of the first conductor 11 and the second conductor 13, made of a monolayer containing Ag or Cu, can be reduced while having the same area and resistance as the first conductor and the second conductor made of a laminate containing a high-melting-point metal layer and a low-melting-point metal layer. If the thickness of each of the first conductor 11 and the second conductor 13 is thin, the amount of molten material that splashes out when the first fuse element 10 melts is also reduced proportionally to the thickness, and the insulation resistance after cutting is increased.

[0158] In this embodiment, the insulating housing 50 includes: a first retaining member 50A, which has at least a first buffer space 51; a second retaining member 50B, which has an internal pressure buffer space 55; a third retaining member 50C, which covers the open surface 56 of the internal pressure buffer space 55; and a cover 50D, which is inserted from a direction orthogonal to the direction in which the first retaining member 50A, the second retaining member 50B and the third retaining member 50C are stacked.

[0159] According to this configuration, the first retaining member 50A, the second retaining member 50B, and the third retaining member 50C are housed in a stacked state within the cover 50D, thus maintaining these retaining members in a mutually fixed state. Therefore, the orientation of a portion of the first terminal 30 and the second terminal 40 disposed between the retaining members, as well as the first fuse element 10, is stable.

[0160] In this embodiment, each of the first filler material 71 and the second filler material 72 is made of elastic resin.

[0161] According to this configuration, each of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10 is surrounded by elastic resin, which can more effectively alleviate the expansion and contraction caused by the thermal expansion difference between the first fuse element 10 and the insulating shell 50.

[0162] In this embodiment, the third filler material 73 comprises at least insulating fibers or silica sand.

[0163] When the third filler material 73 contains at least insulating fibers, the surface area of ​​the third filler material 73 can be ensured, making it easier to increase the overall surface area of ​​the third filler material 73 compared to the plate-shaped case. Furthermore, when the third filler material 73 contains at least insulating fibers, more elements are captured to trap molten debris compared to the plate-shaped case. Therefore, it is easier to suppress a sharp rise in the internal pressure of the protective element 1 caused by molten debris entering the internal pressure buffer space 55.

[0164] When the third filler material 73 contains at least silica sand, the surface area of ​​each silica sand particle can be ensured, making it easier to increase the overall surface area of ​​the third filler material 73 compared to the plate-like case. Therefore, it is easier to suppress the sharp rise in internal pressure of the protective element 1 caused by molten debris entering the internal pressure buffer space 55.

[0165] In this embodiment, flux 75 is applied to at least one surface of the first fusible conductor 12.

[0166] According to this configuration, the first fusible conductor 12 is easily melted when an overcurrent flows, which can increase the overcurrent cut-off speed.

[0167] In this embodiment, the insulating housing 50 is made of polyamide resin or fluorinated resin.

[0168] Based on this composition, polyamide and fluorinated resins exhibit high heat resistance and are difficult to burn. In particular, aliphatic polyamides are unlikely to generate graphite even when burned. Therefore, by forming the insulating shell 50 from aliphatic polyamide, graphite generation caused by arc discharge when the first fuse element 10 melts can be suppressed, thus more reliably preventing the formation of new current paths.

[0169] Furthermore, this embodiment provides an example where the first fuse element 10 comprises a first fusible conductor 12 and a conductor made of different materials, but is not limited thereto. For example, the first fuse element 10 may be composed entirely of Ag or Cu, or may be primarily composed of Ag or Cu. In this case, the first fuse element 10 contains Ag or Cu. The first fuse element 10 may also be a Cu monomer, an Ag monomer, a Cu alloy, or an Ag alloy.

[0170] This invention is not limited to the foregoing embodiments. For example, as described below, modifications to the configuration can be made without departing from the spirit of the invention. Furthermore, in the illustrations of other embodiments and variations, the same reference numerals are used to denote the same constituent elements as in the foregoing embodiments. The differences will be mainly described below.

[0171] (Second Implementation) Regarding the protective element 201 in the second embodiment of the present invention, refer to... Figures 6 to 9 The protection element 201 in the second embodiment differs from that in the first embodiment primarily in that it includes a heating element 80 and a power supply component 81. Furthermore, in the figures of this embodiment, components that are the same or substantially the same as those in the first embodiment are sometimes labeled with the same reference numerals, the same names, etc., and descriptions are omitted.

[0172] Refer to together Figures 6 to 9 The protection element 201 includes: a first fuse element 10; a first terminal 30 and a second terminal 40 connected to the two ends of the first fuse element 10 in the direction of power supply; a heating element 80; a power supply component 81 connected to the heating element 80; and an insulating housing 250 that houses a portion of the first terminal 30 and the second terminal 40, the first fuse element 10, the heating element 80, and a portion of the power supply component 81.

[0173] The protection element 201 of this embodiment serves as a mechanism for cutting off the current path, comprising: an overcurrent cut-off member that, in the event of an overcurrent (a predetermined current) exceeding the rated current flowing through the first fuse element 10, melts the first fuse element 10 to cut off the current path; and an active cut-off member that, in the event of an abnormality other than an overcurrent, supplies current to the heating element 80 to heat it up, thereby melting the first fuse element 10 and cutting off the current path.

[0174] The heating element 80 is stacked vertically with the first fuse element 10. The heating element 80 is in contact with the first fuse element 10 in the vertical direction. The heating element 80 heats up when energized by the power supply component 81, melting and breaking at least a portion of the first fuse element 10. Specifically, the heating element 80 is stacked vertically with the first fusible conductor 12, and is also stacked vertically with the rear end of the first conductor 11 and the front end of the second conductor 13. The heating element 80 melts and breaks at least a portion of the first fusible conductor 12 by heating based on the energized conductor. In the following description, "melting and breaking at least a portion" may sometimes be abbreviated to "melting and breaking," etc.

[0175] In the example shown, the heating element 80 is plate-shaped, with a pair of plate surfaces facing vertically. Viewed from the vertical direction, the heating element 80 is a quadrilateral plate with a larger dimension in the horizontal direction than in the front-back direction. The heating element 80 is disposed in the heating element receiving portion 61 formed in the insulating housing 250. That is, the heating element 80 is housed in the insulating housing 250.

[0176] The heating element receiving portion 61 is a recessed portion recessed from the surface of the second holding member 50B in the insulating housing 250 opposite to the first fuse element 10. In the example shown, the heating element receiving portion 61 is formed by recessing from the lower surface of the second holding member 50B upwards. The heating element receiving portion 61 is disposed on the central side of the second holding member 50B in the front-rear direction. The heating element receiving portion 61 is a quadrilateral hole that extends in the left-right direction. In the example shown, the front-rear dimension of the conductor opposing recess 60 is smaller than the front-rear dimension of the heating element receiving portion 61. The vertical dimension (depth dimension) of the conductor opposing recess 60 is smaller than the vertical dimension of the heating element receiving portion 61.

[0177] The heating element 80 extends in a direction intersecting the current-carrying direction (approximately the front-to-back direction) of the first fuse element 10. In the example shown, it extends in a direction orthogonal to the current-carrying direction (i.e., the left-to-right direction). Although not shown, the heating element 80 includes an insulating substrate (substrate), a resistive layer stacked on the insulating substrate, a metal layer stacked on the insulating substrate and facing the first fuse element 10 in the vertical direction, an insulating layer, and heating element electrodes.

[0178] For example, if an abnormality occurs in the external circuit that serves as the power path for the protection element 201, and it becomes necessary to cut off the power path, the heating element 80 is energized by a current control element provided in the external circuit and heats up.

[0179] The power supply component 81 is a component that supplies power to the heating element 80. The power supply component 81 extends throughout the exterior and interior of the insulating housing 250, and one end of it is connected to the heating element electrode (not shown) of the heating element 80. For example, at least a portion of the power supply component 81 is composed of wires (wiring components). Furthermore, at least a portion of the power supply component 81 is not limited to the above; although not specifically shown, it may also be composed of a conductive plate-shaped component, rod-shaped component, or the like.

[0180] The insulating housing 250 includes: a first retaining member 50A, which forms at least a first buffer space 51; a second retaining member 50B, which forms an internal pressure buffer space 55; a third retaining member 50C, which covers the open surface 56 of the internal pressure buffer space 55; and a first cover 250D1 and a second cover 250D2, which are respectively inserted from two directions orthogonal to the stacking direction of the first retaining member 50A, the second retaining member 50B and the third retaining member 50C.

[0181] In addition, the first buffer space 51 may also be formed in the second retaining member 50B instead of the first retaining member 50A.

[0182] Each of the first cover 250D1 and the second cover 250D2 is a cylindrical shape extending in the front-to-back direction. In the example shown in the figure, each of the first cover 250D1 and the second cover 250D2 is a cylindrical shape with an opening in the front-to-back direction. The front-to-back lengths of the first cover 250D1 and the second cover 250D2 are approximately the same. Three retaining members are housed in the first cover 250D1 and the second cover 250D2 in a side-by-side arrangement in the vertical direction. The first cover 250D1 and the second cover 250D2 hold the three retaining members 50A, 50B, and 50C in a fixed state by means of adhesive bonding or the like. The power supply member 81 extends in the horizontal direction through the gap between the first cover 250D1 and the second cover 250D2.

[0183] Furthermore, the lengths of the first cover 250D1 and the second cover 250D2 in the front-to-back direction can also be different from each other.

[0184] In this embodiment, the leakage hole and / or gap 254 is formed at a different location than the leakage hole and / or gap 54 described above. In the example shown in the figure, two leakage holes and / or gaps 254 are arranged at intervals along the front-to-back direction. The leakage holes and / or gaps 254 extend in a straight line along the vertical direction. The leakage holes and / or gaps 254 extend in a straight line along the left-to-right direction. The leakage holes and / or gaps 254 are disposed near the heating element 80. Viewed from the vertical direction, the leakage holes and / or gaps 254 are arranged along the leading and trailing edges of the heating element 80. The left-to-right dimension of the leakage holes and / or gaps 254 is larger than the left-to-right dimension of the heating element 80. For example, the opening area of ​​the leakage holes and / or gaps 54, 254 (the sum of the cross-sectional areas when each of the leakage holes and / or gaps 54, 254 is cut off by a plane orthogonal to the vertical direction) is the area where the insulating housing 50 approaches or contacts the first fuse element 10, and the length of the area where the first fuse element 10 approaches or contacts the insulating housing 50 in the energizing direction is less than 20%, and there is no restriction outside the area where the insulating housing 50 approaches or contacts the first fuse element 10. For example, the dimension of the leakage hole and / or gap 254 in the left-right direction can also be less than or equal to the dimension of the heating element 80 in the left-right direction. For example, the leakage hole and / or gap 54 may not be formed, but the leakage hole and / or gap 254 may be formed instead. For example, the leakage hole and / or gap 254 may be formed instead of the leakage hole and / or gap 54, or the leakage hole and / or gap 254 may be formed together with the leakage hole and / or gap 54. Furthermore, the options (number, location, shape, opening area, etc.) for leakage holes and / or gaps 54 and 254 are not limited to those mentioned above and can be changed accordingly based on design specifications.

[0185] In the protection element 201 of this embodiment described above, when an overcurrent (i.e., a current exceeding a predetermined value) flows through the first fuse element 10, the first fuse element 10 heats up and melts, thus cutting off the current path. Alternatively, the protection element 201 supplies current to the heating element 80, causing it to heat up, thereby melting and breaking the first fuse element 10 stacked on the heating element 80, thus cutting off the current path. According to this embodiment, a protection element 201 can be provided that, when the first fuse element 10 melts, can suppress large-scale arc discharge, and simultaneously provides overcurrent cutoff and cutoff functions based on a cutoff signal.

[0186] (Third Implementation) Regarding the protective element 301 in the third embodiment of the present invention, refer to... Figure 10 and Figure 11 The protective element 301 of the third embodiment differs from the first embodiment in that it also includes a second fuse element 20 arranged in parallel with the first fuse element 10 and an insulating member 90. Furthermore, in the figures of this embodiment, components that are the same or substantially the same as those in the first embodiment are sometimes labeled with the same reference numerals, the same names, etc., and descriptions are omitted.

[0187] Refer to together Figure 10 and Figure 11 The protection element 301 includes: a second fuse element 20, which is configured in parallel with the first fuse element 10 and connected to the first terminal 30 and the second terminal 40; an insulating member 90, which is disposed between the first fuse element 10 and the second fuse element 20; and an insulating housing 350, which houses a portion of the first terminal 30 and the second terminal 40, the first fuse element 10 and the second fuse element 20 and the insulating member 90.

[0188] The second fuse element 20 is composed of a metal plate-shaped component, sheet-shaped component, or metal foil, etc. In the example shown in the figure, only one second fuse element 20 is provided, but it is not limited to this. For example, two second fuse elements 20 may be provided side by side in the vertical direction, or more than three may be provided side by side. For example, the arrangement of the second fuse elements 20 can be changed accordingly according to the design specifications.

[0189] The second fuse element 20 has a third conductor 21, a second fusible conductor 22, and a fourth conductor 23 connected in series along the current-carrying direction (specifically, the current-carrying direction of the second fuse element 20). For example, the second fusible conductor 22 is made of a material with a lower melting temperature than each of the third conductor 21 and the fourth conductor 23. For example, the resistivity of the second fusible conductor 22 is higher than that of each of the third conductor 21 and the fourth conductor 23. The second fusible conductor 22 functions as the fusible part of the second fuse element 20 when an overcurrent is interrupted.

[0190] The second fusible conductor 22 is plate-shaped, sheet-shaped, or foil-shaped, extending along a plane direction perpendicular to the vertical direction (XY plane direction). In the example shown in the figure, viewed from the vertical direction, the second fusible conductor 22 is a quadrilateral plate-shaped structure with a dimension larger in the horizontal direction than in the front-back direction. The second fusible conductor 22 is disposed at the center of the second fuse element 20 in the front-back direction. In this embodiment, flux 75 is applied to at least one surface of the second fusible conductor 22.

[0191] For example, the second fusible conductor 22 is made of Sn (tin) or a metal with Sn as its main component. Although not shown, the second fusible conductor 22 may also be a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer. For example, the second fusible conductor 22 may be formed of the same material as the first fusible conductor 12. Furthermore, the second fusible conductor 22 is not limited to the above and may also be formed of a different material than the first fusible conductor 12. For example, the material of the second fusible conductor 22 can be changed accordingly according to design specifications.

[0192] Each of the third conductor 21 and the fourth conductor 23 is plate-shaped, sheet-shaped, or foil-shaped. In this embodiment, each of the third conductor 21 and the fourth conductor 23 is a plate-shaped component made of metal. In the example shown in the figure, viewed from the top and bottom, each of the third conductor 21 and the fourth conductor 23 is a roughly quadrilateral plate-shaped component, with its left-right dimension being shorter than its front-back dimension. In this embodiment, each of the third conductor 21 and the fourth conductor 23 is made of Ag or Cu, or a metal with Ag or Cu as its main component.

[0193] The third conductor 21, the second fusible conductor 22, and the fourth conductor 23 are connected in series in this order to form the energizing path of the second fuse element 20. Each of the third conductor 21 and the fourth conductor 23 is connected to the end of the second fusible conductor 22 in the energizing direction of the current flowing through the second fuse element 20 (approximately the front-to-back direction in the example shown in the figure).

[0194] The third conductor 21 is connected to one end of the second fusible conductor 22. In the example shown in the figure, the rear end of the third conductor 21 is fixed to the front end of the second fusible conductor 22. Specifically, the upper surface of the rear end of the third conductor 21 is connected to the lower surface of the front end of the second fusible conductor 22.

[0195] The fourth conductor 23 is connected to the other end of the second fusible conductor 22. In the example shown in the figure, the front end of the fourth conductor 23 is fixed to the rear end of the second fusible conductor 22. Specifically, the upper surface of the front end of the fourth conductor 23 is connected to the lower surface of the rear end of the second fusible conductor 22.

[0196] The second soluble conductor 22 is disposed on the upper surface side of the third conductor 21 and the fourth conductor 23, and is erected between them.

[0197] The first terminal 30 is connected to the third conductor 21. In the example shown in the figure, the rear end of the first terminal 30 is fixed to the front end of the third conductor 21. Specifically, the upper surface of the rear end of the first terminal 30 is connected to the lower surface of the front end of the third conductor 21.

[0198] The second terminal 40 is connected to the fourth conductor 23. In the example shown in the figure, the front end of the second terminal 40 is fixed to the rear end of the fourth conductor 23. Specifically, the upper surface of the front end of the second terminal 40 is connected to the lower surface of the rear end of the fourth conductor 23.

[0199] The third conductor 21 includes: an inner plate portion 21A connected to the second fusible conductor 22; and a third buffer portion 25, which is disposed in the first buffer space 351 surrounded by a first filling material 71 to mitigate physical stress. In the example shown in the figure, each of the first buffer portion 15 and the third buffer portion 25 is disposed in the first buffer space 351 surrounded by the first filling material 71.

[0200] The inner plate portion 21A is a plate-shaped part that extends along a plane direction perpendicular to the vertical direction (XY plane direction). The rear end of the inner plate portion 21A is connected to the front end of the second fusible conductor 22 by welding or the like.

[0201] The third buffer portion 25 is disposed between the front end of the inner side plate portion 21A and the rear end of the first terminal 30. The third buffer portion 25 includes: a first extension portion 25A extending upward from the front end of the inner side plate portion 21A, a second extension portion 25B extending forward from the upper end of the first extension portion 25A, a third extension portion 25C extending downward from the front end of the second extension portion 25B, and a fourth extension portion 25D extending forward from the lower end of the third extension portion 25C. The lower surface of the fourth extension portion 25D is connected to the upper surface of the rear end (conductor connection portion 33) of the first terminal 30. For example, the fourth extension portion 25D is connected to the conductor connection portion 33 of the first terminal 30 by welding or the like.

[0202] In the example shown, the third buffer portion 25 is a curved shape that convexes upwards. In other words, the third buffer portion 25 appears as a cap shape protruding upwards when viewed from the left and right sides. Furthermore, the third buffer portion 25 is not limited to the above; it can also be a curved shape that convexes downwards. For example, the third buffer portion 25 can also appear as a crank shape when viewed from the left and right sides. For example, the shape of the third buffer portion 25 can be changed accordingly according to design specifications.

[0203] The fourth conductor 23 includes: an inner plate portion 23A connected to the second fusible conductor 22; and a fourth buffer portion 26, which is disposed in the second buffer space 352 surrounded by a second filler material 72 to mitigate physical stress. In the example shown in the figure, each of the second buffer portion 16 and the fourth buffer portion 26 is disposed in the second buffer space 352 surrounded by the second filler material 72.

[0204] The inner plate portion 23A is a plate-shaped part that extends in a plane direction perpendicular to the vertical direction (XY plane direction). The front end of the inner plate portion 23A is connected to the rear end of the second fusible conductor 22 by welding or the like.

[0205] A fourth buffer portion 26 is disposed between the rear end of the inner side plate portion 23A and the front end of the second terminal 40. The fourth buffer portion 26 includes: a first extension portion 26A extending upward from the rear end of the inner side plate portion 23A; a second extension portion 26B extending rearward from the upper end of the first extension portion 26A; a third extension portion 26C extending downward from the rear end of the second extension portion 26B; and a fourth extension portion 26D extending rearward from the lower end of the third extension portion 26C. The lower surface of the fourth extension portion 26D is connected to the upper surface of the front end (conductor connection portion 43) of the second terminal 40. For example, the fourth extension portion 26D is connected to the conductor connection portion 43 of the second terminal 40 by welding or the like.

[0206] In the example shown, the fourth buffer portion 26 has a curved shape that convexes upwards. In other words, the fourth buffer portion 26 appears as a cap shape protruding upwards when viewed from the left and right sides. Furthermore, the fourth buffer portion 26 is not limited to the above; it can also have a curved shape that convexes downwards. For example, the fourth buffer portion 26 can also appear as a crank shape when viewed from the left and right sides. For example, the shape of the fourth buffer portion 26 can be changed accordingly according to design specifications.

[0207] The insulating component 90 is plate-shaped, with a pair of plate surfaces facing vertically. In the example shown in the figure, viewed from the vertical direction, the insulating component 90 is a quadrilateral plate with a dimension smaller in the horizontal direction than in the front-back direction. For example, the insulating component 90 is made of a resin product with a leakage current rating (CTI) of 500V or higher. For example, the insulating component 90 is made of a polyamide resin material or a fluoropolymer resin material. Examples of resin materials constituting the insulating component 90 are the same as those for the aforementioned insulating housing 50 (cover 50D and each retaining component).

[0208] The insulating component 90 has a first opposing surface 91 that is close to or in contact with the first fuse element 10, and a second opposing surface 92 that is close to or in contact with the second fuse element 20. In the example shown in the figure, the lower surface of the insulating component 90 corresponds to the first opposing surface 91, and the upper surface of the insulating component 90 corresponds to the second opposing surface 92.

[0209] Although not shown, a slit portion opening vertically and extending horizontally may be formed on the outer side of the insulating member 90, further back than the fusible conductor. The slit portion extends in a direction orthogonal to the direction of current flow (approximately back-and-forth direction) of the fuse elements 10 and 20. If the slit portion is formed in the insulating member 90, the molten debris adhering to the first opposing surface 91 and the second opposing surface 92 of the insulating member 90 after the fuse elements 10 and 20 are cut will be discontinuous in the slit portion, which can appropriately increase the insulation resistance between the first terminal 30 and the second terminal 40 after the cut.

[0210] In the insulating housing 350, a first buffer space 351 is provided around the first buffer portion 15 and the third buffer portion 25, a second buffer space 352 is provided around the second buffer portion 16 and the fourth buffer portion 26, a first element receiving space 353A is provided outside the periphery of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10, a second element receiving space 353B is provided outside the periphery of the third buffer portion 25 and the fourth buffer portion 26 of the second fuse element 20, and an internal pressure buffer space 55 is formed that communicates with each of the first element receiving space 353A and the second element receiving space 353B via a leakage hole and / or gap 54. The insulating housing 350 is configured to be close to or in contact with the periphery of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10, and the periphery of the third buffer portion 25 and the fourth buffer portion 26 of the second fuse element 20.

[0211] The insulating housing 350 includes: a first retaining member 50A, which forms at least a first buffer space 351; a second retaining member 350B, which forms an internal pressure buffer space 55; a third retaining member 350C, which covers the open surface 56 of the internal pressure buffer space 55; and a cover 50D, which is inserted from a direction orthogonal to the direction of stacking the first retaining member 50A, the second retaining member 350B and the third retaining member 350C.

[0212] The first retaining member 50A is disposed on the lower side of the first terminal 30, the second terminal 40, and the first fuse element 10. The first retaining member 50A includes a terminal mounting surface 57, a terminal locking portion 58, and a conductor opposing recess 360.

[0213] The conductor-facing recess 360 of the first holding member 50A is a recessed portion extending downward from the central side of the first fuse element 10 in the front-rear direction on the upper surface of the first holding member 50A. The conductor-facing recess 360 of the first holding member 50A is a generally quadrilateral hole opening upward. The bottom surface of the conductor-facing recess 360 is a planar surface facing upward, extending along a plane direction perpendicular to the vertical direction (XY plane direction). The bottom surface of the conductor-facing recess 360 of the first holding member 50A is opposite to the lower surface of the first fusible conductor 12.

[0214] The second retaining member 350B is disposed on the upper side of the first terminal 30, the second terminal 40, and the second fuse element 20. The upper surface of the second retaining member 350B forms the open surface 56 of the inner pressure buffer space 55. The second retaining member 350B has a terminal pressing surface 59 and a conductor opposing recess 360.

[0215] The conductor-facing recess 360 of the second holding member 350B is a recessed portion extending upward from the central side of the second fuse element 20 in the front-rear direction on the lower surface of the second holding member 350B. The conductor-facing recess 360 of the second holding member 350B is a generally quadrilateral hole opening downward. The bottom surface of the conductor-facing recess 360 of the second holding member 350B is a planar surface facing downward, extending along a plane direction perpendicular to the vertical direction (XY plane direction). The bottom surface of the conductor-facing recess 360 of the second holding member 350B is opposite to the upper surface of the second fusible conductor 22.

[0216] A through hole 365 with an opening in the vertical direction is formed in the second retaining member 350B. The through hole 365 is configured to be stacked with the first buffer space 351 and the second buffer space 352 when viewed from the vertical direction.

[0217] The third retaining member 350C includes a protrusion 366 that protrudes downward from a portion extending in a surface direction perpendicular to the vertical direction and enters the through hole 365. The protrusion 366 is arranged in a manner that it overlaps with the first buffer space 351 and the second buffer space 352 when viewed from the vertical direction. In the example shown in the figure, a gap is formed between the outer wall surface of the protrusion 366 in the front-rear direction and the wall surface forming the through hole 365.

[0218] The three retaining components 50A, 350B, and 350C are housed in a vertically aligned arrangement within the cover 50D via the insulating component 90. The cover 50D holds the three retaining components 50A, 350B, and 350C, as well as the insulating component 90, in a fixed manner by means of adhesive bonding or the like.

[0219] With the first retaining member 50A, the insulating member 90, the second retaining member 350B, and the third retaining member 350C combined, a first buffer space 351 and a second buffer space 352 are formed in the portion surrounded by the first retaining member 50A, the insulating member 90, the second retaining member 350B, and the third retaining member 350C. Each of the first buffer space 351 and the second buffer space 352 is formed by a portion of the through hole 365 formed in the second retaining member 350B and is separated by a portion of the protrusion 366 protruding from the third retaining member 350C.

[0220] With the components 50A, 90, 350B, and 350C combined as described above, a first element receiving space 353A is formed between the first holding member 50A and the insulating member 90. The first fuse element 10 is received within the first element receiving space 353A. With the components 50A, 90, 350B, and 350C combined as described above, a second element receiving space 353B is formed between the second holding member 350B and the insulating member 90. The second fuse element 20 is received within the second element receiving space 353B.

[0221] A portion of the upper surface of the first retaining member 50A (a portion of the surface facing the first element receiving space 353A) is configured such that it approaches or contacts the lower surface of the portion other than the periphery of the first buffer portion 15 and the portion other than the periphery of the second buffer portion 16 of the first fuse element 10. The first opposing surface 91, which is the lower surface of the insulating member 90, is configured such that it approaches or contacts the upper surface of the portion other than the periphery of the first buffer portion 15 and the portion other than the periphery of the second buffer portion 16 of the first fuse element 10.

[0222] A portion of the lower surface of the second retaining member 350B (a portion of the surface facing the second element receiving space 353B) is configured such that it approaches or contacts the upper surface of the portion other than the periphery of the third buffer portion 25 and the periphery of the fourth buffer portion 26 of the second fuse element 20. The second opposing surface 92, which is the upper surface of the insulating member 90, is configured such that it approaches or contacts the lower surface of the portion other than the periphery of the third buffer portion 25 and the periphery of the fourth buffer portion 26 of the second fuse element 20.

[0223] When the second retaining member 350B and the third retaining member 350C are combined, an internal pressure buffer space 55 is formed between the second retaining member 350B and the third retaining member 350C. The internal pressure buffer space 55 is a generally cuboid space that is connected to the first element receiving space 353A and the second element receiving space 353B via a leakage hole and / or gap 54.

[0224] In the example shown in the figure, filler materials 71 and 72 are respectively filled with a portion of the buffer spaces 351 and 352 (in other words, a portion of the through hole 365) with gaps between them. For example, firstly, after mounting the second retaining member 350B on the first retaining member 50A and before mounting the third retaining member 350C on the second retaining member 350B, filler materials 71 and 72 are respectively placed into the buffer spaces 351 and 352 through the through hole 365. At this time, the amount of filler materials 71 and 72 can also be adjusted by taking into account the volume of the protrusion 366 of the third retaining member 350C. Then, the protrusion 366 is inserted into the through hole 365, and the third retaining member 350C is installed on the second retaining member 350B. Thus, filler materials 71 and 72 can be respectively filled with a portion of the buffer spaces 351 and 352 (in other words, a portion of the through hole 365) with gaps between them.

[0225] Furthermore, the filling materials 71 and 72 are not limited to filling a portion of the buffer spaces 351 and 352 with gaps between them, but can also fill the buffer spaces 351 and 352 completely without gaps. For example, the filling materials 71 and 72 only need to be arranged in at least a portion of the buffer spaces 351 and 352, and at least in a manner that surrounds the buffer portions 15, 16, 25, and 26.

[0226] In the protective element 301 of this embodiment described above, the first buffer portion 15 of the first fuse element 10 and the third buffer portion 25 of the second fuse element 20 are surrounded by a first filling material 71, and the second buffer portion 16 of the first fuse element 10 and the fourth buffer portion 26 of the second fuse element 20 are surrounded by a second filling material 72. Therefore, around each of the first fuse element 10 and the second fuse element 20, gas, which is one of the sources of arc discharge generated during overcurrent interruption, can be effectively eliminated. As a result, plasma generated by the ionization of gas, which is one of the sources of arc discharge, can be suppressed, thereby suppressing arc discharge. Furthermore, physical stress is alleviated in each of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10, and in each of the third buffer portion 25 and the fourth buffer portion 26 of the second fuse element 20. Therefore, the expansion and contraction caused by the thermal expansion difference of the first fuse element 10, the second fuse element 20, the insulating member 90, and the insulating shell 350 can be more effectively mitigated.

[0227] (Fourth Implementation) Regarding the protective element 401 in the fourth embodiment of the present invention, refer to... Figure 12The protection element 401 in the fourth embodiment differs from that in the third embodiment primarily in that it includes a heating element 80 and a power supply component 81. Furthermore, in the figures of this embodiment, components that are the same or substantially the same as those in the first to third embodiments are sometimes labeled with the same reference numerals, the same names, etc., and descriptions are omitted.

[0228] Refer to together Figure 12 The protection element 401 includes: a first fuse element 10; a first terminal 30 and a second terminal 40 connected to the two ends of the first fuse element 10 in the energizing direction; a heating element 80; and a power supply component 81 connected to the heating element 80. Figure 12 (Not shown in the figure); a second fuse element 20, which is configured in parallel with the first fuse element 10 and connected to the first terminal 30 and the second terminal 40; an insulating component 90, which is disposed between the first fuse element 10 and the second fuse element 20; and an insulating housing 450, which houses a portion of the first terminal 30 and the second terminal 40, the first fuse element 10 and the second fuse element 20, the heating element 80, a portion of the power supply component 81 and the insulating component 90.

[0229] The protection element 401 of this embodiment serves as a mechanism for cutting off the current path, comprising: an overcurrent cut-off member that, in the event of an overcurrent (a predetermined current) exceeding the rated current flowing through the fuse elements 10 and 20, melts the fuse elements 10 and 20 to cut off the current path; and an active cut-off member that, in the event of an abnormality other than an overcurrent, supplies current to the heating element 80 to heat it up, thereby melting the fuse elements 10 and 20 and cutting off the current path.

[0230] In this embodiment, the locations where each fuse element 10, 20 connects to each fusible conductor 12, 22 are opposite to those in the third embodiment described above. Specifically, in the first fuse element 10, the upper surface of the rear end portion of the first conductor 11 is connected to the lower surface of the front end portion of the first fusible conductor 12, and the upper surface of the front end portion of the second conductor 13 is connected to the lower surface of the rear end portion of the first fusible conductor 12. On the other hand, in the second fuse element 20, the lower surface of the rear end portion of the third conductor 21 is connected to the upper surface of the front end portion of the second fusible conductor 22, and the lower surface of the front end portion of the fourth conductor 23 is connected to the upper surface of the rear end portion of the second fusible conductor 22.

[0231] In the example shown in the figure, a pair of conductor-opposing recesses 460 are formed in the insulating member 90 along the vertical direction. In the pair of conductor-opposing recesses 460, a first soluble conductor 12 is disposed on the lower portion, and a second soluble conductor 22 is disposed on the upper portion. In the pair of conductor-opposing recesses 460, the lower portion is recessed upwards from the central portion in the front-rear direction of the lower surface of the insulating member 90, and the upper portion is recessed downwards from the central portion in the front-rear direction of the upper surface of the insulating member 90. In the pair of conductor-opposing recesses 460, the bottom surface of the lower portion faces the upper surface of the first soluble conductor 12, and the bottom surface of the upper portion faces the lower surface of the second soluble conductor 22. The pair of conductor-opposing recesses 460 are disposed on the central side in the front-rear direction of the insulating member 90.

[0232] A pair of heating elements 80 are arranged vertically. The pair of heating elements 80 are stacked vertically with each fuse element 10, 20. The lower heating element 80 of the pair of heating elements 80 contacts the first fuse element 10 vertically, and the upper heating element 80 contacts the second fuse element 20 vertically. The heating elements 80 are heated by energization from the power supply component 81, melting and breaking at least a portion of each fuse element 10, 20. Specifically, the lower heating element 80 of the pair of heating elements 80 is stacked vertically with the first fusible conductor 12 and is stacked vertically with the rear end of the first conductor 11 and the front end of the second conductor 13, respectively. The upper heating element 80 is stacked vertically with the second fusible conductor 22 and is stacked vertically with the rear end of the third conductor 21 and the front end of the fourth conductor 23, respectively. The pair of heating elements 80 melt and break at least a portion of each fusible conductor 12, 22 by heating based on energization.

[0233] In the example shown in the figure, the lower heating element 80 of the pair of heating elements 80 is disposed in the heating element receiving portion 461 formed in the first holding member 50A, and the upper heating element 80 is disposed in the heating element receiving portion 461 formed in the second holding member 350B. That is, the pair of heating elements 80 are housed in the insulating housing 450.

[0234] In the protection element 401 of this embodiment described above, when an overcurrent (i.e., a predetermined current) exceeding the rated current flows through the fuse elements 10 and 20, the fuse elements 10 and 20 heat up and melt, thus cutting off the current path. Furthermore, the protection element 401 supplies current to the heating element 80, causing it to heat up, thereby melting and breaking the fuse elements 10 and 20 stacked on the heating element 80, thus cutting off the current path. According to this embodiment, a protection element 401 can be provided that, when the fuse elements 10 and 20 melt, suppresses large-scale arc discharge, and simultaneously provides overcurrent cutoff and cutoff based on a cutoff signal.

[0235] Without departing from the spirit of the invention, the various components described in the foregoing embodiments and modifications can be combined, and additions, omissions, substitutions, and other modifications to the components are possible. Furthermore, the invention is not limited to the foregoing embodiments, but only to the claims.

[0236] Explanation of reference numerals in the attached figures 1. 201, 301, 401 Protective Components 10 First fuse element 11 First conductor 12 First fusible conductor 13 Second conductor 15 First Buffer Section 16 Second Buffer Section 20 Second fuse element 21 Third conductor 22 Second fusible conductor 23 Fourth conductor 25 Third Buffer Section 26 Fourth Buffer Section 30 First terminal 40 Second terminal 50, 250, 350, 450 Insulating Housings 50A First Holding Component 50B Second Holding Component 50C Third Holding Component 50D cover 51, 351 First Buffer Space 52, 352 Second Buffer Space 53 Component Accommodation Space 54. Leakage holes and / or gaps 55 Internal pressure buffer space 56 Open face 71 First Filling Material 72 Second Filler Material 73 Third Filler Material 75 flux 80 heating element 81 Power Supply Components 90 Insulating components 91 First Opposite Surface 92 Second Opposite Surface 250D1 First Cover 250D2 Second Cover 254 Leakage holes and / or gaps 350B Second Holding Component 350C Third Holding Component 353A First Component Accommodation Space 353B Second component housing space.

Claims

1. A protective element comprising: First fuse element; The first terminal and the second terminal are connected to the two ends of the first fuse element in the direction of energization; and An insulating housing that houses a portion of the first and second terminals and the first fuse element. The first fuse element has a first conductor and a first fusible conductor connected in series along the current-carrying direction of the first fuse element. The first conductor has a first buffer portion to mitigate physical stress. In the insulating housing, a first buffer space is formed around the first buffer portion. The protective element further comprises a first filling material, which is disposed in the first buffer space in a manner that surrounds the first buffer portion. The insulating housing is configured to be close to or in contact with a portion of the first buffer portion of the first fuse element, other than the periphery of the first buffer portion.

2. The protective element according to claim 1, wherein, The first fuse element also has a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element. The first conductor is connected to one end of the first fusible conductor. The second conductor is connected to the other end of the first fusible conductor. The first terminal is connected to the first conductor. The second terminal is connected to the second conductor. The second conductor has a second buffer portion to alleviate physical stress. In the insulating housing, a second buffer space is formed around the second buffer portion. The protective element also includes a second filling material, which is disposed in the second buffer space in a manner that surrounds the second buffer portion.

3. The protective element according to claim 1 or 2, wherein, In the insulating housing, an element receiving space is formed at a location other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffer space is connected to the element receiving space via a leakage hole and / or gap. The protective element also includes a third filling material disposed in at least a portion of the internal pressure buffer space.

4. The protective element according to claim 2, wherein, Both the first conductor and the second conductor are plate-shaped components made of metal. The insulating shell is configured such that it is close to or in contact with a plate-shaped surface portion and a back portion that are outside the periphery of the first buffer portion of the first conductor and outside the periphery of the second buffer portion of the second conductor.

5. The protective element according to claim 2 or 4, wherein, The first conductor and the second conductor are each made of Ag or Cu, or a metal with Ag or Cu as the main component.

6. The protective element according to claim 1 or 2, wherein, The first fusible conductor is made of Sn or a metal with Sn as its main component.

7. The protective element according to claim 1 or 2, wherein, The first fusible conductor is a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer.

8. The protective element according to claim 7, wherein, The high-melting-point metal layer is made of Ag or Cu, or a metal with Ag or Cu as the main component. The low-melting-point metal layer is made of Sn or a metal with Sn as the main component.

9. The protective element according to claim 3, wherein, The insulating housing comprises: A first retaining member having at least the first buffer space; The second retaining component has the aforementioned internal pressure buffer space; The third retaining component shields the open surface of the internal pressure buffer space; as well as The cover is inserted from a direction orthogonal to the direction in which the first retaining member, the second retaining member, and the third retaining member are stacked.

10. The protective element according to claim 2, wherein, Both the first filler material and the second filler material are made of elastic resin.

11. The protective element according to claim 10, wherein, The elastic resin is a silicone resin or a light-cured acrylic resin.

12. The protective element according to claim 3, wherein, The third filler material comprises at least insulating fibers or silica sand.

13. The protective element according to claim 12, wherein, The insulating fiber is ceramic fiber paper.

14. The protective element according to claim 1 or 2, wherein, At least one surface of the first fusible conductor is coated with flux.

15. The protective element according to claim 1 or 2, wherein, The insulating shell is made of polyamide resin or fluorinated resin.

16. A protective element comprising: First fuse element; The first terminal and the second terminal are connected to the two ends of the first fuse element in the direction of energization. Heating element; A power supply component connected to the heating element; as well as An insulating housing that houses a portion of the first and second terminals, the first fuse element, the heating element, and a portion of the power supply component. The first fuse element has a first conductor and a first fusible conductor connected in series along the current-carrying direction of the first fuse element. The first conductor has a first buffer portion to mitigate physical stress. In the insulating housing, a first buffer space is formed around the first buffer portion. The protective element further comprises a first filling material, which is disposed in the first buffer space in a manner that surrounds the first buffer portion. The insulating housing is configured to be close to or in contact with a portion of the first buffer portion of the first fuse element, other than the periphery of the first buffer portion.

17. The protective element according to claim 16, wherein, The first fuse element also has a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element. The first conductor is connected to one end of the first fusible conductor. The second conductor is connected to the other end of the first fusible conductor. The first terminal is connected to the first conductor. The second terminal is connected to the second conductor. The second conductor has a second buffer portion to alleviate physical stress. In the insulating housing, a second buffer space is formed around the second buffer portion. The protective element also includes a second filling material, which is disposed in the second buffer space in a manner that surrounds the second buffer portion.

18. The protective element according to claim 16 or 17, wherein, In the insulating housing, an element receiving space is formed at a location other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffer space is connected to the element receiving space via a leakage hole and / or gap. The protective element also includes a third filling material disposed in at least a portion of the internal pressure buffer space.

19. The protective element according to claim 17, wherein, Both the first conductor and the second conductor are plate-shaped components made of metal. The insulating shell is configured such that it is close to or in contact with a plate-shaped surface portion and a back portion that are outside the periphery of the first buffer portion of the first conductor and outside the periphery of the second buffer portion of the second conductor.

20. The protective element according to claim 17 or 19, wherein, The first conductor and the second conductor are each made of Ag or Cu, or a metal with Ag or Cu as the main component.

21. The protective element according to claim 16 or 17, wherein, The first fusible conductor is made of Sn or a metal with Sn as its main component.

22. The protective element according to claim 16 or 17, wherein, The first fusible conductor is a laminate comprising a high-melting-point metal layer and a low-melting-point metal layer.

23. The protective element according to claim 22, wherein, The high-melting-point metal layer is made of Ag or Cu, or a metal with Ag or Cu as the main component. The low-melting-point metal layer is made of Sn or a metal with Sn as the main component.

24. The protective element according to claim 18, wherein, The insulating housing comprises: A first retaining member having at least the first buffer space; The second retaining component has the aforementioned internal pressure buffer space; A third retaining component shields the open surface of the internal pressure buffer space; and The first cover and the second cover are inserted from two directions orthogonal to the direction in which the first retaining member, the second retaining member and the third retaining member are stacked.

25. The protective element according to claim 17, wherein, Both the first filler material and the second filler material are made of elastic resin.

26. The protective element according to claim 25, wherein, The elastic resin is a silicone resin or a light-cured acrylic resin.

27. The protective element according to claim 18, wherein, The third filler material comprises at least insulating fibers or silica sand.

28. The protective element according to claim 27, wherein, The insulating fiber is ceramic fiber paper.

29. The protective element according to claim 16 or 17, wherein, At least one surface of the first fusible conductor is coated with flux.

30. The protective element according to claim 16 or 17, wherein, The insulating shell is made of polyamide resin or fluorinated resin.

31. The protective element according to claim 1, wherein, have: The second fuse element is configured in parallel with the first fuse element and is connected to the first terminal and the second terminal; and An insulating component, disposed between the first fuse element and the second fuse element, has a first opposing surface that approaches or contacts the first fuse element and a second opposing surface that approaches or contacts the second fuse element. The second fuse element has a third conductor and a second fusible conductor connected in series along the energizing direction of the second fuse element. The third conductor includes a third buffer portion, which is disposed in the first buffer space in a manner surrounded by the first filling material, to mitigate physical stress. The insulating housing is configured to be close to or in contact with a portion of the third buffer portion of the second fuse element, other than the periphery of the second fuse element.

32. The protective element according to claim 31, wherein, The first fuse element also has a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element. The first conductor is connected to one end of the first fusible conductor. The second conductor is connected to the other end of the first fusible conductor. The first terminal is connected to the first conductor. The second terminal is connected to the second conductor. The second conductor has a second buffer portion to alleviate physical stress. In the insulating housing, a second buffer space is formed around the second buffer portion. The protective element also includes a second filling material, which is disposed in the second buffer space in a manner that surrounds the second buffer portion.

33. The protective element according to claim 32, wherein, The second fuse element also has a fourth conductor connected in series with the second fusible conductor along the energizing direction of the second fuse element. The third conductor is connected to one end of the second fusible conductor. The fourth conductor is connected to the other end of the second fusible conductor. The first terminal is connected to the third conductor. The second terminal is connected to the fourth conductor. The fourth conductor has a fourth buffer portion, which is disposed in the second buffer space in a manner surrounded by the second filling material to alleviate physical stress.

34. The protective element according to any one of claims 31 to 33, wherein, In the insulating housing, a first element receiving space is formed at a location other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffer space is connected to the first element receiving space via a leakage hole and / or gap. The protective element also includes a third filling material disposed in at least a portion of the internal pressure buffer space.

35. The protective element according to claim 34, wherein, In the insulating housing, a second element receiving space is formed at a location other than the periphery of the third buffer portion of the second fuse element. The second element receiving space is in communication with the internal pressure buffer space via the leakage hole and / or gap.

36. The protective element according to claim 16, wherein, have: The second fuse element is configured in parallel with the first fuse element and is connected to the first terminal and the second terminal; and An insulating component, disposed between the first fuse element and the second fuse element, has a first opposing surface that approaches or contacts the first fuse element and a second opposing surface that approaches or contacts the second fuse element. The second fuse element has a third conductor and a second fusible conductor connected in series along the energizing direction of the second fuse element. The third conductor includes a third buffer portion, which is disposed in the first buffer space in a manner surrounded by the first filling material, to mitigate physical stress. The insulating housing is configured to be close to or in contact with a portion of the third buffer portion of the second fuse element, other than the periphery of the second fuse element.

37. The protective element according to claim 36, wherein, The first fuse element also has a second conductor connected in series with the first fusible conductor along the energizing direction of the first fuse element. The first conductor is connected to one end of the first fusible conductor. The second conductor is connected to the other end of the first fusible conductor. The first terminal is connected to the first conductor. The second terminal is connected to the second conductor. The second conductor has a second buffer portion to alleviate physical stress. In the insulating housing, a second buffer space is formed around the second buffer portion. The protective element also includes a second filling material, which is disposed in the second buffer space in a manner that surrounds the second buffer portion.

38. The protective element according to claim 37, wherein, The second fuse element also has a fourth conductor connected in series with the second fusible conductor along the energizing direction of the second fuse element. The third conductor is connected to one end of the second fusible conductor. The fourth conductor is connected to the other end of the second fusible conductor. The first terminal is connected to the third conductor. The second terminal is connected to the fourth conductor. The fourth conductor has a fourth buffer portion, which is disposed in the second buffer space in a manner surrounded by the second filling material to alleviate physical stress.

39. The protective element according to any one of claims 36 to 38, wherein, In the insulating housing, a first element receiving space is formed at a location other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffer space is connected to the first element receiving space via a leakage hole and / or gap. The protective element also includes a third filling material disposed in at least a portion of the internal pressure buffer space.

40. The protective element according to claim 39, wherein, In the insulating housing, a second element receiving space is formed at a location other than the periphery of the third buffer portion of the second fuse element. The second element receiving space is in communication with the internal pressure buffer space via the leakage hole and / or gap.

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