Protection element

Abstract

To suppress arc discharge during interruption, enable high voltage and current interruption, and suppress the decrease in insulation resistance after interruption.SOLUTION: A protection element 1 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 current-carrying direction, and an insulating case 50 that accommodates a part of the first terminal 30 and the second terminal 40 and the first fuse element 10. The first fuse element 10 includes a first conductor 11 and a first fusible conductor 12 connected in series in the current-carrying direction. The first conductor 11 includes a first buffer portion 15 that relieves physical stress. In the insulating case 50, a first buffer space 51 is formed around the first buffer portion 15. The protection element 1 further includes a first filler 71 arranged in the first buffer space 51 so as to surround the first buffer portion 15. The insulating case 50 is configured to be in close proximity to or in contact with a portion of the first fuse element 10 other than the periphery of the first buffer portion 15.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, there are fuse elements that generate heat and melt to cut off the current path when a current exceeding the rated value flows through the current path. Protective devices equipped with fuse elements (fuse elements) are used in a wide range of fields, from home appliances to electric vehicles.

[0003] For example, lithium-ion batteries are used in a wide range of applications, from mobile devices to electric vehicles (EVs) and storage batteries, and their capacity is increasing. As the capacity of lithium-ion batteries increases, the voltage becomes higher, at several hundred volts, and the current also becomes higher, at several hundred to several thousand amperes.

[0004] The following techniques are available for forming heat spots in a foil-like fuse element by using holes, thickness changes, notches, etc., to melt the fuse element in the event of an overcurrent. For example, Patent Document 1 discloses a fuse in which the thickness of the interrupting portion of a conductive thin-film pattern formed on an insulating substrate is set to be thinner than the thickness of a connecting portion connected in series to the interrupting portion. For example, Patent Documents 2 and 3 disclose fuse elements in which a melting portion is formed by punching holes in a plurality of elements arranged in parallel. For example, Patent Documents 4 and 5 disclose fuses in which a conductive thin film pattern formed on the surface of an insulating substrate has a cutoff section having multiple cutoff section narrow sections arranged in parallel, the thickness of the cutoff section being thinner than the thickness of a connecting strip connected in series to the cutoff section. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6057413 [Patent Document 2] Patent No. 6199368 [Patent Document 3] Patent No. 5952751 [Patent Document 4] Patent No. 5116119 [Patent Document 5] Patent No. 4998890 Summary of the Invention [Problem to be solved by the invention]

[0006] Arc discharge during interruption is an issue for protective elements compatible with high voltage and large current interruption. Generally, to suppress arc discharge, silica sand, known as an arc-extinguishing agent, is filled around the fuse element. In addition, as protective elements become smaller and less resistant (shorter), the fuse element's melting part is made wider and thicker. In this case, the molten debris continuously adheres to the surface of the arc-extinguishing agent, forming a conductive path, which is likely to reduce the interruption characteristics. There is also a concern that the risk of a decrease in insulation resistance after interruption increases.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a protection element that suppresses arc discharge during interruption, is capable of interrupting high voltages and large currents, and can suppress a decrease in insulation resistance after interruption. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following means.

[0009] [Aspect 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 current flow direction; and an insulating case that accommodates a portion of the first terminal and the second terminal and the first fuse element, wherein the first fuse element has a first conductor and a first fusible conductor connected in series in the current flow direction of the first fuse element, the first conductor having a first buffer portion that relieves physical stress, a first buffer space is formed around the first buffer portion in the insulating case, and the insulating case is further configured to be in close proximity to or in contact with a portion of the first fuse element other than the periphery of the first buffer portion.

[0010] [Aspect 2] The first fuse element further has a second conductor connected in series with the first soluble conductor in the direction of current flow of the first fuse element, the first conductor is connected to one end of the first soluble conductor and the second conductor is connected to the other end of the first soluble conductor, the first terminal is connected to the first conductor, and the second terminal is connected to the second conductor, the second conductor has a second buffer section that relieves physical stress, the insulating case has a second buffer space formed around the second buffer section, and the protective element described in aspect 1 further includes a second filler arranged in the second buffer space to surround the second buffer section.

[0011] [Aspect 3] A protective element as described in aspect 1 or 2, wherein the insulating case has an element accommodating space formed in a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space communicating with the element accommodating space via a leak hole and / or a gap, and further comprises a third filler disposed in at least a portion of the internal pressure buffering space.

[0012] [Aspect 4] A protective element as described in Aspect 2, wherein each of the first conductor and the second conductor is a metal plate-shaped member, and the insulating case is configured to be in close proximity to or in contact with front and back surfaces of the plate-shaped members other than the periphery of the first buffer portion of the first conductor and the periphery of the second buffer portion of the second conductor.

[0013] [Aspect 5] The protective element according to aspect 2 or 4, wherein each of the first conductor and the second conductor is made of Ag or Cu, or a metal containing Ag or Cu as a main component.

[0014] [Aspect 6] The protection element according to any one of aspects 1 to 5, wherein the first soluble conductor is made of Sn or a metal mainly composed of Sn.

[0015] [Aspect 7] The protection element according to any one of aspects 1 to 6, wherein the first soluble conductor is a laminate including a high melting point metal layer and a low melting point metal layer.

[0016] [Aspect 8] The protective element of aspect 7, wherein the high-melting point metal layer is made of Ag or Cu, or a metal mainly composed of Ag or Cu, and the low-melting point metal layer is made of Sn or a metal mainly composed of Sn.

[0017] [Aspect 9] The protective element described in Aspect 3, wherein the insulating case includes at least a first retaining member in which the first buffer space is formed, a second retaining member in which the internal pressure buffer space is formed, a third retaining member that covers the open surface of the internal pressure buffer space, and a cover that is inserted from a direction perpendicular to the direction in which the first retaining member, the second retaining member, and the third retaining member are stacked.

[0018] [Aspect 10] The protective element according to aspect 2, wherein each of the first filler and the second filler is made of an elastic resin.

[0019] [Aspect 11] The protective element according to aspect 10, wherein the elastic resin is a silicone resin or a photocurable acrylic resin.

[0020] [Aspect 12] A protective element according to aspect 3, wherein the third filler contains at least insulating fiber or silica sand.

[0021] [Aspect 13] The protective element described in Aspect 12, wherein the insulating fiber is ceramic fiber paper.

[0022] [Aspect 14] The protection element according to any one of aspects 1 to 13, wherein flux is applied to at least one surface of the first soluble conductor.

[0023] [Aspect 15] A protective element according to any one of aspects 1 to 14, wherein the insulating case is made of a polyamide resin or a fluorine resin.

[0024] [Aspect 16] 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 a current flow direction, a heating element, a power supply member connected to the heating element, a portion of the first terminal and the second terminal, the first fuse element, the heating element, and an insulating case that houses a portion of the power supply member, wherein the first fuse element has a first conductor and a first fusible conductor connected in series in the current flow direction of the first fuse element, the first conductor having a first buffer portion that relieves physical stress, a first buffer space is formed around the first buffer portion in the insulating case, and the insulating case is further configured to be in close proximity to or in contact with a portion of the first fuse element other than the periphery of the first buffer portion.

[0025] [Aspect 17] The first fuse element further has a second conductor connected in series with the first soluble conductor in the direction of current flow of the first fuse element, the first conductor is connected to one end of the first soluble conductor and the second conductor is connected to the other end of the first soluble conductor, the first terminal is connected to the first conductor, and the second terminal is connected to the second conductor, the second conductor has a second buffer section that relieves physical stress, the insulating case has a second buffer space formed around the second buffer section, and the protective element described in Aspect 16 further includes a second filler arranged in the second buffer space to surround the second buffer section.

[0026] [Aspect 18] A protective element as described in aspect 16 or 17, wherein the insulating case has an element accommodating space formed in a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space connected to the element accommodating space via a leak hole and / or a gap, and further comprises a third filler disposed in at least a portion of the internal pressure buffering space.

[0027] [Aspect 19] A protective element as described in Aspect 17, wherein each of the first conductor and the second conductor is a metal plate-shaped member, and the insulating case is configured to be in close proximity to or in contact with front and back surfaces of the plate-shaped members other than the periphery of the first buffer portion of the first conductor and other than the periphery of the second buffer portion of the second conductor.

[0028] [Aspect 20] The protection element according to aspect 17 or 19, wherein each of the first conductor and the second conductor is made of Ag or Cu, or a metal containing Ag or Cu as a main component.

[0029] [Aspect 21] The protection element according to any one of aspects 16 to 20, wherein the first soluble conductor is made of Sn or a metal mainly composed of Sn.

[0030] [Aspect 22] A protection element according to any one of aspects 16 to 21, wherein the first soluble conductor is a laminate including a high melting point metal layer and a low melting point metal layer.

[0031] [Aspect 23] The protective element of aspect 22, wherein the high-melting point metal layer is made of Ag or Cu, or a metal mainly composed of Ag or Cu, and the low-melting point metal layer is made of Sn or a metal mainly composed of Sn.

[0032] [Aspect 24] The protective element described in Aspect 18, wherein the insulating case includes at least a first retaining member in which the first buffer space is formed, a second retaining member in which the internal pressure buffer space is formed, a third retaining member that covers the open surface of the internal pressure buffer space, and a first cover and a second cover that are inserted respectively from both directions perpendicular to the direction in which the first retaining member, the second retaining member, and the third retaining member are stacked.

[0033] [Aspect 25] A protective element described in Aspect 17, wherein each of the first filler and the second filler is made of an elastic resin.

[0034] [Aspect 26] A protection element according to aspect 25, wherein the elastic resin is a silicone resin or a photocurable acrylic resin.

[0035] [Aspect 27] A protective element described in Aspect 18, wherein the third filler contains at least insulating fiber or silica sand.

[0036] [Aspect 28] A protection element described in Aspect 27, wherein the insulating fiber is ceramic fiber paper.

[0037] [Aspect 29] A protection element as described in any one of aspects 16 to 28, wherein flux is applied to at least one surface of the first fusible conductor.

[0038] [Aspect 30] A protective element described in any one of aspects 16 to 29, wherein the insulating case is made of polyamide resin or fluorine-based resin.

[0039] [Aspect 31] A protection element as described in Aspect 1, comprising: a second fuse element arranged in parallel with the first fuse element and connected to the first terminal and the second terminal; and an insulating member arranged between the first fuse element and the second fuse element, the insulating member having a first opposing surface in close proximity to or in contact with the first fuse element and a second opposing surface in close proximity 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 in the current flow direction of the second fuse element, the third conductor being arranged in the first buffer space so as to be surrounded by the first filler and comprising a third buffer portion that relieves physical stress, and the insulating case being configured to be in close proximity to or in contact with a portion of the second fuse element other than the periphery of the third buffer portion.

[0040] [Aspect 32] The first fuse element further has a second conductor connected in series with the first soluble conductor in the direction of current flow of the first fuse element, the first conductor is connected to one end of the first soluble conductor and the second conductor is connected to the other end of the first soluble conductor, the first terminal is connected to the first conductor, and the second terminal is connected to the second conductor, the second conductor has a second buffer section that relieves physical stress, the insulating case has a second buffer space formed around the second buffer section, and the protective element described in Aspect 31 further has a second filler arranged in the second buffer space to surround the second buffer section.

[0041] [Aspect 33] The second fuse element further has a fourth conductor connected in series with the second soluble conductor in the current flow direction of the second fuse element, the third conductor is connected to one end of the second soluble conductor and the fourth conductor is connected to the other end of the second soluble conductor, the first terminal is connected to the third conductor, and the second terminal is connected to the fourth conductor, the fourth conductor is arranged in the second buffer space so as to be surrounded by the second filler, and has a fourth buffer portion that relieves physical stress, as described in aspect 32.

[0042] [Aspect 34] A protective element described in any one of aspects 31 to 33, wherein the insulating case has a first element accommodating space in a region other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space communicating with the first element accommodating space via a leak hole and / or a gap, and further comprises a third filler arranged in at least a portion of the internal pressure buffering space.

[0043] [Aspect 35] A protective element as described in Aspect 34, wherein a second element accommodating space is formed in the insulating case in a portion other than the periphery of the third buffer portion of the second fuse element, and the second element accommodating space is connected to the internal pressure buffering space via the leak hole and / or gap.

[0044] [Aspect 36] A protection element as described in Aspect 16, comprising: a second fuse element arranged in parallel with the first fuse element and connected to the first terminal and the second terminal; and an insulating member arranged between the first fuse element and the second fuse element, the insulating member having a first opposing surface in close proximity to or in contact with the first fuse element and a second opposing surface in close proximity 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 in the current flow direction of the second fuse element, the third conductor being arranged in the first buffer space so as to be surrounded by the first filler and comprising a third buffer portion that relieves physical stress, and the insulating case being configured to be in close proximity to or in contact with a portion of the second fuse element other than the periphery of the third buffer portion.

[0045] [Aspect 37] The first fuse element further has a second conductor connected in series with the first soluble conductor in the direction of current flow of the first fuse element, the first conductor is connected to one end of the first soluble conductor and the second conductor is connected to the other end of the first soluble conductor, the first terminal is connected to the first conductor, and the second terminal is connected to the second conductor, the second conductor has a second buffer section that relieves physical stress, the insulating case has a second buffer space formed around the second buffer section, and the protective element described in Aspect 36 further includes a second filler arranged in the second buffer space to surround the second buffer section.

[0046] [Aspect 38] The second fuse element further has a fourth conductor connected in series with the second soluble conductor in the current flow direction of the second fuse element, the third conductor is connected to one end of the second soluble conductor and the fourth conductor is connected to the other end of the second soluble conductor, the first terminal is connected to the third conductor, and the second terminal is connected to the fourth conductor, the fourth conductor is arranged in the second buffer space so as to be surrounded by the second filler, and has a fourth buffer portion that relieves physical stress, as described in aspect 37.

[0047] [Aspect 39] A protective element described in any one of aspects 36 to 38, wherein the insulating case has a first element accommodating space in a region other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space communicating with the first element accommodating space via a leak hole and / or a gap, and further comprises a third filler arranged in at least a portion of the internal pressure buffering space.

[0048] [Aspect 40] A protective element as described in Aspect 39, wherein a second element accommodating space is formed in the insulating case in a portion other than the periphery of the third buffer portion of the second fuse element, and the second element accommodating space is connected to the internal pressure buffering space via the leak hole and / or gap. Effect of the Invention

[0049] According to the present invention, it is possible to provide a protection element that can suppress arc discharge during interruption, can handle high voltage and large current interruption, and can suppress a decrease in insulation resistance after interruption. [Brief description of the drawings]

[0050] [Figure 1] FIG. 3 is a diagram showing the protective element of the first embodiment, and is a cross-sectional view taken along line II in FIG. 2. [Diagram 2] FIG. 2 is a diagram showing a protection element of the first embodiment, and is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 3 is a side view of the protection element of the first embodiment, taken along the line III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. [Diagram 5] FIG. 2 is a cross-sectional view of FIG. 1 . [Figure 6] FIG. 8 is a cross-sectional view taken along line VI-VI in FIG. 7, showing a protection element according to a second embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6, showing a protection element according to a second embodiment. [Figure 8] 8 is a side view of the protection element according to the second embodiment, taken along the line VIII in FIG. 7. [Figure 9] IX-IX cross-sectional view of FIG. 6. [Figure 10] FIG. 11 is a cross-sectional view showing a protection element according to a third embodiment, the cross-sectional view corresponding to FIG. [Figure 11] 11 is a cross-sectional view taken along the line XI-XI of FIG. [Figure 12] FIG. 11 is a cross-sectional view showing a protection element according to a fourth embodiment, the cross-sectional view corresponding to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. The drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately modified and implemented within the scope of the effects of the present invention.

[0052] (First embodiment) A protection element according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 5. The protection element according to this embodiment constitutes a part of a high-voltage, high-current (100V / 100A or more) electric circuit that uses, for example, a lithium-ion secondary battery. The protection element is mounted on, for example, an electric vehicle (EV).

[0053] 1 to 5, the protection element 1 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 current flow direction, and an insulating case 50 that accommodates parts 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 apart from each other in a predetermined direction. Each of the first terminal 30 and the second terminal 40 is plate-shaped.

[0054] The protection element 1 has an overcurrent interruption mechanism as a mechanism for interrupting the current path, in which the first fuse element 10 melts to interrupt the current path when an overcurrent (current equal to or greater than a specified value) exceeding the rated current flows through the first fuse element 10.

[0055] In the following, an XYZ orthogonal coordinate system (three-dimensional orthogonal coordinate system) may be set in each drawing, and each configuration may be explained. The above-mentioned predetermined direction in which the first terminal 30 and the second terminal 40 are aligned is called the front-rear direction. The front-rear direction corresponds to the X-axis direction in each drawing. In the X-axis direction, the direction from the second terminal 40 to the first terminal 30 (-X side) is called the front side, and the direction from the first terminal 30 to the second terminal 40 (+X side) is called the rear side. Note that the front-rear direction is the direction connecting the first terminal 30 and the second terminal 40, and is also the direction in which electricity flows when the protection element 1 is in use, so it may also be referred to as the current flow direction.

[0056] The direction in which the plate surfaces of the first terminal 30 and the second terminal 40 face is called the up-down direction. The up-down direction is a direction perpendicular to the front-rear direction, and corresponds to the Z-axis direction in each drawing. In the up-down direction, the upper side corresponds to the +Z side, and the lower side corresponds to the -Z side.

[0057] The direction perpendicular to the front-rear direction and the up-down direction is called the left-right direction. The left-right direction corresponds to the Y-axis direction in each drawing. In the left-right direction, the left side corresponds to the -Y side, and the right side corresponds to the +Y side. In detail, the -Y side is the left side when the protective element 1 is viewed from the rear (+X side), and the +Y side is the right side when the protective element 1 is viewed from the rear. The left-right direction may also be referred to as the width direction. In this case, for example, one side in the width direction corresponds to the -Y side, and the other side in the width direction corresponds to the +Y side.

[0058] In this embodiment, the terms "front", "rear", "upper", "lower", "left" and "right" are convenient names for easily explaining the relative positional relationships of each component, and the actual positional relationships may be other than those indicated by these names.

[0059] (1st terminal, 2nd terminal) Each of the first terminal 30 and the second terminal 40 has a plate shape extending in a plane direction (XY plane direction) perpendicular to the up-down direction. In the example shown in the figure, each of the first terminal 30 and the second terminal 40 has a substantially rectangular plate shape. The first terminal 30 and the second terminal 40 are disposed apart from each other in the front-rear direction.

[0060] 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 case 50 and is exposed to the outside of the insulating case 50. 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 case 50 and is exposed to the outside of the insulating case 50.

[0061] The first terminal 30 comprises a terminal body 31 having an external terminal hole 32 formed therein, a conductor connection portion 33 connected to the front end portion of the first fuse element 10, and a locking claw 34 engaged with a terminal locking portion 58 of the insulating case 50.

[0062] The terminal body 31 is a rectangular plate that is long in the front-rear direction. The rear portion of the terminal body 31 is disposed between the terminal mounting surface 57 and the terminal pressing surface 59 at the front portion of the insulating case 50, and is sandwiched between the terminal mounting surface 57 and the terminal pressing surface 59. The external terminal hole 32 is a circular hole that passes through the terminal body 31 in the vertical direction. The conductor connecting 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 connecting portion 33 by soldering or the like. The locking claws 34 protrude in the left-right direction beyond the terminal body 31. Specifically, the locking claws 34 are provided to protrude from both left and right ends of the conductor connecting portion 33.

[0063] The second terminal 40 comprises a terminal body 41 having an external terminal hole 42 formed therein, a conductor connection portion 43 connected to the rear end portion of the first fuse element 10, and a locking claw 44 engaged with a terminal locking portion 58 of the insulating case 50.

[0064] The terminal body 41 is a rectangular plate that is long in the front-rear direction. The front portion 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 case 50, and is sandwiched between the terminal mounting surface 57 and the terminal pressing surface 59. The external terminal hole 42 is a circular hole that passes through the terminal body 41 in the vertical direction. The conductor connecting 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 connecting portion 43 by soldering or the like. The locking claws 44 protrude in the left-right direction beyond the terminal body 41. Specifically, the locking claws 44 are provided to protrude from both left and right ends of the conductor connecting portion 43.

[0065] For example, one of the pair of external terminal holes 32, 42 is connected to the power supply side, and the other is connected to the load side. Note that, without being limited to the above, the external terminal holes 32, 42 may be connected to a current path inside the load. For example, the connection mode of the external terminal holes 32, 42 can be changed according to the design specifications.

[0066] For example, each of the first terminal 30 and the second terminal 40 is made of a metal such as copper, brass, or nickel. As the material for the first terminal 30 and the second terminal 40, it is preferable to use brass from the viewpoint of strengthening rigidity, and it is preferable to use copper from the viewpoint of reducing electrical resistance. When using copper, it is preferable to perform an anti-rust treatment such as nickel plating, silver plating, or tin plating on the surface. The first terminal 30 and the second terminal 40 may be made of the same material or may be made of different materials. For example, the material for each of the first terminal 30 and the second terminal 40 can be changed according to the design specifications.

[0067] (First fuse element) The first fuse element 10 is made of a metal plate-like member, sheet-like member, metal foil, or the like. In the illustrated example, only one first fuse element 10 is provided, but this is not limiting. For example, two first fuse elements 10 may be provided side by side in the vertical direction, or three or more first fuse elements 10 may be provided side by side. For example, the installation mode of the first fuse element 10 can be changed according to design specifications.

[0068] The first fuse element 10 has a first conductor 11, a first soluble conductor 12, and a second conductor 13 connected in series in the current flow direction. For example, the first soluble conductor 12 is made of a material having a lower melting temperature than each of the first conductor 11 and the second conductor 13. For example, the first soluble conductor 12 has a higher electrical resistivity than each of the first conductor 11 and the second conductor 13. The first soluble conductor 12 functions as a melting portion of the first fuse element 10 when an overcurrent is interrupted.

[0069] The first soluble conductor 12 is plate-shaped, sheet-shaped, or foil-shaped, and extends in a plane direction (XY plane direction) perpendicular to the vertical direction. In the example shown in the figure, the first soluble conductor 12 is a rectangular plate shape whose left-right dimension is larger than its front-rear dimension when viewed from the vertical direction. The first soluble conductor 12 is disposed in the center of the first fuse element 10 in the front-rear direction. In this embodiment, flux 75 is applied to at least one surface of the first soluble conductor 12.

[0070] For example, the first soluble conductor 12 is made of Sn (tin) or a metal mainly composed of Sn. Although not shown, the first soluble conductor 12 may be a laminate including a high melting point metal layer and a low melting point metal layer. This laminate may have one or more low melting point metal layers, two or more high melting point metal layers, and the low melting point metal layers may be arranged between the high melting point metal layers. This laminate may be formed, for example, by coating the periphery of the low melting point metal layer with a high melting point metal layer.

[0071] For example, the high melting point metal layer of the laminate is made of Ag (silver) or Cu (copper), or a metal mainly composed of Ag or Cu. The high melting point metal layer of the laminate may contain Ag or Cu, and may be Ag alone, Cu alone, an Ag alloy, or a Cu alloy. The Ag alloy is an alloy with the highest Ag content among the metals contained in the alloy, and the Cu alloy is an alloy with the highest Cu content among the metals contained in the alloy.

[0072] For example, the low melting point metal layer of the laminate is made of Sn or a metal mainly composed of Sn. The low melting point metal layer of the laminate may contain Sn, and may be Sn alone or an Sn alloy. The Sn alloy is an alloy mainly composed of Sn. The Sn alloy is an alloy with the highest Sn content among metals contained in the alloy. Examples of the Sn alloy include Sn-Bi alloy, In-Sn alloy, Sn-Ag-Cu alloy, etc.

[0073] The laminate may have a two-layer structure of a low-melting-point metal layer / a high-melting-point metal layer, or may have a multilayer structure of three or more layers having two or more high-melting-point metal layers and one or more low-melting-point metal layers, with the low-melting-point metal layers being disposed between the high-melting-point metal layers. In addition, the first soluble conductor 12 may be composed of a single layer of a low melting point metal layer containing Sn.

[0074] 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 metal plate-shaped member. In the example shown in the figure, each of the first conductor 11 and the second conductor 13 is a substantially rectangular plate-shaped member whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction. In this embodiment, each of the first conductor 11 and the second conductor 13 is made of Ag or Cu, or a metal mainly composed of Ag or Cu. When copper is used, it is preferable to perform an anti-rust treatment such as nickel plating, silver plating, or tin plating on the surface.

[0075] The first conductor 11, the first soluble conductor 12, and the second conductor 13 are connected in series in this order to form a current path of the first fuse element 10. Each of the first conductor 11 and the second conductor 13 is connected to an end of the first soluble conductor 12 in the current direction (approximately the front-rear direction in the example shown in the figure) in which current flows through the first fuse element 10.

[0076] The first conductor 11 is connected to one end of the first soluble conductor 12. In the example shown in the figure, the rear end of the first conductor 11 is fixed onto the front end of the first soluble 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 soluble conductor 12. The second conductor 13 is connected to the other end of the first soluble conductor 12. In the example shown in the figure, the front end of the second conductor 13 is fixed onto the rear end of the first soluble 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 soluble conductor 12. The first soluble conductor 12 is arranged on the lower surface side of the first conductor 11 and the second conductor 13 and spans between them. In addition, the vertical relationship of the connection between the first soluble conductor 12 and the first conductor 11 and the second conductor 13 is not limited, and the first soluble conductor 12 may be arranged on the upper surface side of the first conductor 11 and the second conductor 13.

[0077] The first terminal 30 and the first conductor 11 are connected. In the example shown in the figure, the rear end of the first terminal 30 is fixed onto the front end of the first conductor 11. That is, the lower surface of the rear end of the first terminal 30 and the upper surface of the front end of the first conductor 11 are connected to each other. The second terminal 40 is connected to the second conductor 13. In the illustrated example, the front end of the second terminal 40 is fixed onto the rear end of the second conductor 13. That is, the lower surface of the front end of the second terminal 40 and the upper surface of the rear end of the second conductor 13 are connected to each other. The vertical relationship of the connection between the first terminal 30 and the first conductor 11 and the vertical relationship of the connection between the second terminal 40 and the second conductor 13 are not limited, and 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 may be connected to each other, or 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 may be connected to each other.

[0078] The first conductor 11 includes an inner plate portion 11A connected to the first soluble conductor 12, and a first buffer portion 15 that relieves physical stress.

[0079] The inner plate portion 11A is a plate extending in a plane direction (XY plane direction) perpendicular to the up-down direction. The rear end portion of the inner plate portion 11A is connected to the front end portion of the first soluble conductor 12 by soldering or the like.

[0080] The first buffer portion 15 is disposed between the front end of the inner 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 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 soldering or the like.

[0081] In the illustrated example, the first buffer section 15 has a bent shape that is convex downward. In other words, the first buffer section 15 has a hat shape that protrudes downward when viewed from the left-right direction. The first buffer section 15 is not limited to the above, and may have a bent shape that is convex upward. For example, the first buffer section 15 may have a crank shape when viewed from the left-right direction. For example, the shape of the first buffer section 15 can be changed according to design specifications.

[0082] The second conductor 13 includes an inner plate portion 13A connected to the first soluble conductor 12 and a second buffer portion 16 that relieves physical stress.

[0083] The inner plate portion 13A is a plate extending in a plane direction (XY plane direction) perpendicular to the up-down direction. The front end portion of the inner plate portion 13A is connected to the rear end portion of the first soluble conductor 12 by soldering or the like.

[0084] The second buffer portion 16 is disposed between the rear end of the inner 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 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 (conductor connection portion 43) of the second terminal 40. For example, the fourth extension portion 16D is connected to the conductor connection portion 43 of the second terminal 40 by soldering or the like.

[0085] In the illustrated example, the second buffer section 16 has a bent shape that protrudes downward. In other words, the second buffer section 16 has a hat shape that protrudes downward when viewed from the left-right direction. The second buffer section 16 is not limited to the above, and may have a bent shape that protrudes upward. For example, the second buffer section 16 may have a crank shape when viewed from the left-right direction. For example, the shape of the second buffer section 16 can be changed according to design specifications.

[0086] (insulating case) The insulating case 50 has a columnar shape extending in the front-rear direction. In the insulating case 50, a first buffer space 51 is formed around the first buffer section 15, a second buffer space 52 is formed around the second buffer section 16, an element accommodating space 53 is formed in a portion of the first fuse element 10 other than the periphery of the first buffer section 15 and other than the periphery of the second buffer section 16, and an internal pressure buffer space 55 is formed which communicates with the element accommodating space 53 via a leak hole and / or a gap 54. The insulating case 50 is configured to be in close proximity to or in contact with a portion of the first fuse element 10 other than the periphery of the first buffer section 15 and other than the periphery of the second buffer section 16.

[0087] The insulating case 50 comprises a first retaining member 50A in which at least a first buffer space 51 is formed, a second retaining member 50B in which an internal pressure buffer space 55 is formed, a third retaining member 50C that covers an open surface 56 of the internal pressure buffer space 55, and a cover 50D that is inserted from a direction perpendicular to the direction in which the first retaining member 50A, the second retaining member 50B, and the third retaining member 50C are stacked. The first buffer space 51 may be formed in the second holding member 50B instead of the first holding member 50A.

[0088] The first holding member 50A is disposed at the lowermost position among the three holding members. The first holding member 50A is disposed below the first terminal 30, the second terminal 40, and the first fuse element 10. The first holding member 50A includes a terminal mounting surface 57, a terminal locking portion 58, and a conductor-facing recess 60.

[0089] The terminal mounting surface 57 is concave and recessed downward from the top surface of the first holding member 50A. The bottom surface of the terminal mounting surface 57 is flat and faces upward, and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. A pair of terminal mounting surfaces 57 are provided on the first holding member 50A. The pair of terminal mounting surfaces 57 are disposed at both ends of the first holding member 50A in the front-rear direction.

[0090] The terminal locking portion 58 is disposed on a side wall erected on the outer portion in the left-right direction of the first holding member 50A. The terminal locking portion 58 is a groove extending in the up-down direction (in other words, a concave shape recessed outward in the left-right direction). The terminal locking portion 58 is a wall surface along the upper surface of the first holding member 50A and the portion of the side wall that opens to face inward in the left-right direction. The terminal locking portions 58 are disposed on both ends in the front-rear direction of the first holding member 50A, one pair on each side (i.e., four in total).

[0091] The conductor facing recess 60 is a recess that is recessed downward from the central portion of the upper surface of the first holding member 50A in the front-rear direction of the first fuse element 10. The conductor facing recess 60 is a substantially rectangular hole that opens upward. The bottom surface of the conductor facing recess 60 is a flat surface facing upward and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. The bottom surface of the conductor facing recess 60 faces the lower surface of the first soluble conductor 12. The conductor facing recess 60 is disposed on the central side of the first holding member 50A in the front-rear direction. The dimension of the conductor facing recess 60 in the front-rear direction is larger than the dimension of the first soluble conductor 12 in the front-rear direction. The conductor-facing recess 60 may be formed on the side of the second holding member 50B facing the first fuse element 10.

[0092] The second holding member 50B is disposed in the vertical center of the three holding members. The second holding 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 holding member 50B constitutes an open surface 56 of the internal pressure buffering space 55. The second holding member 50B has a terminal pressing surface 59.

[0093] The terminal pressing surface 59 is concave and recessed upward from the lower surface of the second holding member 50B. The bottom surface of the terminal pressing surface 59 is flat and faces downward, and extends in a plane direction perpendicular to the up-down direction (XY plane direction). A pair of terminal pressing surfaces 59 are provided on the second holding member 50B. The pair of terminal pressing surfaces 59 are arranged at both ends of the second holding member 50B in the front-rear direction. The terminal pressing surface 59 may be formed on the side of the first holding member 50A facing the first terminals 30 and the second terminals 40.

[0094] The third holding member 50C is disposed at the uppermost position of the three holding members. The third holding member 50C has a shape that spreads in a plane direction perpendicular to the up-down direction. The lower surface of the third holding member 50C is flat and aligned with the upper surface (open surface 56) of the second holding member 50B.

[0095] The cover 50D is tubular and extends in the front-rear direction. In the illustrated example, the cover 50D is cylindrical and opens in the front-rear direction. The three holding members 50A, 50B, 50C are housed in the cover 50D in a combined state lined up in the vertical direction. The cover 50D holds the three holding members 50A, 50B, 50C in a fixed state by adhesive or the like.

[0096] When the first holding member 50A and the second holding member 50B are combined, a first buffer space 51, a second buffer space 52, and an element accommodating space 53 are formed between the first holding member 50A and the second holding member 50B. The first fuse element 10 is accommodated in the element accommodating space 53.

[0097] A part of the upper surface of the first holding member 50A (a part of the surface facing the element accommodating space 53) is configured to be in close proximity to or in contact with the lower surface of a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10. A part of the lower surface of the second holding member 50B (a part of the surface facing the element accommodating space 53) is configured to be in close proximity to or in contact with the upper surface of a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10.

[0098] Each of the first buffer space 51 and the second buffer space 52 is formed between the inner wall surface of the recess recessed downward from the upper surface of the first holding member 50A and the lower surface of the second holding member 50B. Each of the first buffer space 51 and the second buffer space 52 is a rectangular parallelepiped long in the left-right direction when viewed from the top-bottom direction. The first buffer space 51 is formed in the front end portion of the first holding member 50A. The first buffer space 51 is disposed between the rear end of the front terminal mounting surface 57 of the first holding member 50A and a part of the surface facing the front part of the element accommodating space 53. The second buffer space 52 is formed in the rear end portion of the first holding member 50A. The second buffer space 52 is disposed between the front end of the rear terminal mounting surface 57 of the first holding member 50A and a part of the surface facing the rear part of the element accommodating space 53.

[0099] When the second holding member 50B and the third holding member 50C are combined, an internal pressure buffering space 55 is formed between the second holding member 50B and the third holding member 50C. The internal pressure buffering space 55 is a substantially rectangular parallelepiped space, and communicates with the element accommodating space 53 via a leak hole and / or a gap 54. For example, the vertical dimension of the internal pressure buffering space 55 is 1 / 3 or more and 1 / 2 or less of the vertical dimension (outer height) of the entire protection element 1. The internal pressure buffering space 55 has the effect of suppressing a sudden rise in the internal pressure of the protection element 1 caused by gas generated by an arc discharge that occurs when the first fuse element 10 melts.

[0100] In the illustrated example, four leak holes and / or gaps 54 are arranged at intervals in the front-rear direction, and a pair is arranged in the left-right direction. The leak holes and / or gaps 54 extend linearly along the up-down direction. For example, the opening area of ​​the leak holes and / or gaps 54 (the cross-sectional area when the leak holes and / or gaps 54 are cut by a plane perpendicular to the up-down direction) is 20% or less of the length in the current-carrying direction of the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other in the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other, and there is no restriction outside the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other. The form (number, arrangement, shape, opening area, etc.) of the leak holes and / or gaps 54 is not limited to the above and can be changed according to the design specifications.

[0101] For example, the cover 50D and each of the holding members 50A, 50B, and 50C are preferably made of a material having a CTI (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more. The CTI can be determined by a test based on IEC60112.

[0102] A resin material can be used as the material for the cover 50D and each of the holding members 50A, 50B, and 50C. A resin material has a smaller heat capacity and a lower melting point than a ceramic material. For this reason, using a resin material as the material for the holding members is preferable because it has the property of weakening the arc discharge caused by gasification cooling (ablation) and the property that when the melted and scattered metal particles adhere to the holding member, the surface of the holding member is deformed or the adhered matter is aggregated, making the metal particles sparse and making it difficult to form a conductive path.

[0103] As the resin material, for example, polyamide-based resin or fluororesin can be used. In this embodiment, the insulating case 50 is made of polyamide-based resin or fluororesin. The polyamide-based resin may be an aliphatic polyamide or a semi-aromatic polyamide. Examples of the aliphatic polyamide include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of the semi-aromatic polyamide include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. Examples of the fluororesin include polytetrafluoroethylene. In addition, polyamide-based resin and fluororesin have high heat resistance and are difficult to burn. In particular, aliphatic polyamide is difficult to generate graphite even when burned. For this reason, by forming the cover 50D and each holding member using aliphatic polyamide, it is possible to more reliably prevent the formation of a new current path by graphite generated by arc discharge when the first fuse element 10 is blown.

[0104] (1st filler, 2nd filler) The protective element 1 further includes a first filler 71 disposed in the first buffer space 51 so as to surround the first buffer section 15, and a second filler 72 disposed in the second buffer space 52 so as to surround the second buffer section 16. In this embodiment, each of the first filler 71 and the second filler 72 is made of an elastic resin. The elastic resin is a silicone resin or a photocurable acrylic resin.

[0105] Each of the first filler 71 and the second filler 72 is not limited to the above elastic resin, and may be silicone oil. For example, each of the first filler 71 and the second filler 72 is not limited to a solid, and may be a fluid material such as a liquid or gel. For example, each of the first filler 71 and the second filler 72 may have a function of excluding gas from each buffer space while maintaining the buffering action of each buffer part. For example, the first filler 71 and the second filler 72 may be the same as each other, or may be different from each other. For example, the form of each of the first filler 71 and the second filler 72 can be changed according to the design specifications.

[0106] In the illustrated example, the fillers 71 and 72 are respectively filled in the buffer spaces 51 and 52. For example, first, before the second holding member 50B is mounted on the first holding member 50A, the fillers 71 and 72 are respectively placed in the buffer spaces 51 and 52. Thereafter, the second holding member 50B is attached to the first holding member 50A, whereby the fillers 71 and 72 can be respectively filled in the buffer spaces 51 and 52.

[0107] The fillers 71 and 72 do not necessarily have to be completely filled into the buffer spaces 51 and 52, respectively, without leaving any gaps, and may be filled with some gaps in the buffer spaces 51 and 52, respectively. For example, it is sufficient that the fillers 71 and 72 are disposed in at least a part of the buffer spaces 51 and 52, respectively, and disposed so as to surround at least the buffer sections 15 and 16.

[0108] (Third filler) The protective element 1 further includes a third filler 73 disposed in at least a part of the internal pressure buffering space 55. The third filler 73 has a function of filtering and cooling metal gas generated by arc discharge that occurs in a part to be interrupted in a circuit through which an excessive current flows, thereby quickly and safely extinguishing the arc discharge. In this embodiment, the third filler 73 includes at least insulating fiber or silica sand.

[0109] The insulating fiber is ceramic fiber paper. Although not shown, a plurality of ceramic fiber papers may be arranged in a stack in the internal pressure buffering space 55. The third filler 73 is not limited to the insulating fiber described above, and may be other fiber materials. For example, the fiber material may be a ceramic material such as SiO2, MgO, Al2O3, or ZrO2, or a plastic material such as nylon or PMMA. The type of the fiber material is not limited to the above, and may be changed according to the design specifications.

[0110] Silica sand is granular SiO2 (quartz glass). Silica sand is sand that is mainly composed of quartz grains. Specifically, silica sand is a white coarse-grained sand that contains a large amount of quartz grains among sandy deposits and weathering products whose main components are silicates.

[0111] The third filler 73 is not limited to the above, and various materials can be used. For example, the third filler 73 may be a spherical member (for example, ceramic beads or ceramic balls) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the third filler 73 may be a porous member (for example, porous ceramic) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the third filler 73 may be a spherical member (for example, plastic beads or plastic balls) made of a plastic material such as nylon or PMMA (acrylic resin). For example, the third filler 73 may be a porous member (for example, porous plastic) made of a plastic material such as nylon or PMMA. For example, the third filler 73 may be formed of a sheet-like member, or may be in the shape of wool, a board, a block, or the like. For example, the third filler 73 may be a plate-like member (for example, plate-like ceramic) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the third filler 73 may be silicone. Silicone is an inorganic polymer having a main chain of siloxane bonds in which silicon (Si) and oxygen (O) are repeatedly arranged. For example, the form of the third filling material 73 can be changed according to design specifications.

[0112] In the illustrated example, the third filling material 73 is filled in the internal pressure buffering space 55 inside the protection element 1. A part of the third filling material 73 is in contact with the bottom surface of a recess that forms the internal pressure buffering space 55 in the second holding member 50B located above the first fuse element 10. For example, first, before the third holding member 50C (corresponding to a lid member that constitutes the insulating case 50) is mounted on the second holding member 50B, the third filling material 73 is placed in the internal pressure buffering space 55. Thereafter, the third holding member 50C is attached to the second holding member 50B, whereby the internal pressure buffering space 55 can be filled with the third filling material 73.

[0113] The third filling material 73 does not necessarily have to fill the internal pressure buffering space 55 completely without any gaps, but may fill the internal pressure buffering space 55 with gaps in part. For example, the third filling material 73 may be disposed in at least a part of the internal pressure buffering space 55 and may be in contact with the bottom surface of the recess that forms the internal pressure buffering space 55.

[0114] The orientation of the protection element 1 is not limited to being arranged so that its up-down direction is along the direction of gravity, and it may be arranged so that it intersects with the direction of gravity. For example, when the third filler 73 is filled without any gaps in the internal pressure buffering space 55, even if the protection element 1 is arranged at an angle with respect to the direction of gravity, it will be in contact with the bottom surface of the recess that forms the internal pressure buffering space 55. For example, the arrangement of the protection element 1 can be changed according to the design specifications.

[0115] (Effects of this embodiment) The protective element 1 of the present 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 current-carrying direction, and an insulating case 50 that accommodates a part 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 current-carrying direction. The first conductor 11 includes a first buffer section 15 that relieves physical stress. In the insulating case 50, a first buffer space 51 is formed around the first buffer section 15. The protective element 1 further includes a first filler 71 arranged in the first buffer space 51 so as to surround the first buffer section 15. The insulating case 50 is configured to be in close proximity to or in contact with a portion of the first fuse element 10 other than the periphery of the first buffer section 15. According to this configuration, the space formed between the insulating case 50 and the portion other than the periphery of the first buffer portion 15 of the first fuse element 10 is narrowed. In addition, the first buffer portion 15 of the first fuse element 10 is surrounded by the first filler 71. Therefore, the gas, which is one of the sources of arc discharge that occurs when an overcurrent is interrupted, can be eliminated as much as possible around the first fuse element 10. This suppresses plasma that is generated by ionizing the gas, which is one of the sources of arc discharge, and suppresses arc discharge. In addition, in order to suppress arc discharge, it is not necessary to fill the periphery of the first fuse element 10 with silica sand, which is called an arc-extinguishing agent. Therefore, problems caused by continuous adhesion of molten spatter to the surface of the arc-extinguishing agent (problems of degrading interruption characteristics and decreasing insulation resistance after interruption) do not occur. Therefore, it is possible to provide a protection element 1 that suppresses arc discharge during interruption, is capable of dealing with high voltage and large current interruption, and can suppress a decrease in insulation resistance after interruption. In addition, since physical stress is alleviated in the first buffer portion 15 of the first fuse element 10, it is possible to mitigate expansion / contraction and deformation due to the difference in thermal expansion between the first fuse element 10 and the insulating case 50. This ensures the reliability of the protection element 1 against temperature cycles. This makes it possible to simultaneously suppress arc discharge and alleviate the thermal expansion / contraction stress of the first fuse element 10 due to the temperature cycles of the protection element 1.

[0116] In this embodiment, the first fuse element 10 further includes a second conductor 13 connected in series with the first soluble conductor 12 in the current-carrying direction. The first conductor 11 is connected to one end of the first soluble conductor 12. The second conductor 13 is connected to the other end of the first soluble conductor 12. The first terminal 30 and the first conductor 11 are connected. The second terminal 40 and the second conductor 13 are connected. The second conductor 13 includes a second buffer section 16 that relieves physical stress. In the insulating case 50, a second buffer space 52 is formed around the second buffer section 16. The protective element 1 further includes a second filler 72 arranged in the second buffer space 52 so as to surround the second buffer section 16. According to this configuration, since the second buffer portion 16 of the first fuse element 10 is surrounded by the second filler 72, it is possible to eliminate as much as possible gas, which is one of the sources of arc discharge that occurs when an overcurrent is interrupted, around the first fuse element 10. This makes it possible to suppress plasma that is generated by ionizing the gas, which is one of the sources of arc discharge, and to suppress arc discharge. In addition, since physical stress is relieved in each of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10, it is possible to more effectively mitigate expansion / contraction and deformation due to the difference in thermal expansion between the first fuse element 10 and the insulating case 50.

[0117] In this embodiment, the insulating case 50 is formed with an element accommodating space 53 in a portion other than the periphery of the first buffer portion 15 of the first fuse element 10, and an internal pressure buffering space 55 communicating with the element accommodating space 53 via a leak hole and / or a gap 54. The protection element 1 further includes a third filler 73 disposed in at least a portion of the internal pressure buffering space 55. According to this configuration, the insulating case 50 suppresses the occurrence of arc discharge, while the third filler 73 sufficiently suppresses a sudden increase in the internal pressure of the protection element 1 caused by molten debris entering the internal pressure buffering space 55. Therefore, it is possible to suppress the occurrence of a large-scale arc discharge when the first fuse element 10 melts.

[0118] In this embodiment, each of the first conductor 11 and the second conductor 13 is a metal plate-like member. The insulating case 50 is configured to be in close proximity to or in contact with a front surface portion and a back surface portion of the plate-like member other than the periphery of the first buffer portion 15 of the first conductor 11 and other than the periphery of the second buffer portion 16 of the second conductor 13. According to this configuration, the first buffer section 15 of the first conductor 11 and the second buffer section 16 of the second conductor 13 can each be formed by bending. For example, the first buffer section 15 and the second buffer section 16 can each be easily formed by bending (pressing). In addition, it is possible to suppress the occurrence of arc discharge in the front and back surfaces of the plate-like body other than the periphery of the first buffer section 15 of the first conductor 11 and other than the periphery of the second buffer section 16 of the second conductor 13.

[0119] In this embodiment, each of the first conductor 11 and the second conductor 13 is made of Ag or Cu, or a metal containing Ag or Cu as a main component. According to this configuration, the electrical resistivity is likely to be smaller than that of a laminate including a high melting point metal layer and a low melting point metal layer, respectively, of the first conductor 11 and the second conductor 13. Therefore, the first conductor 11 and the second conductor 13 made of a single layer including Ag or Cu can be made thinner even if they have the same electrical resistance in the same area as those made of a laminate including 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 scattered when the first fuse element 10 melts is reduced in proportion to the thickness, and the insulation resistance after interruption is increased.

[0120] In this embodiment, the insulating case 50 includes a first retaining member 50A having at least a first buffer space 51 formed therein, a second retaining member 50B having an internal pressure buffer space 55 formed therein, a third retaining member 50C that covers the open surface 56 of the internal pressure buffer space 55, and a cover 50D that is inserted from a direction perpendicular to the direction in which the first retaining member 50A, the second retaining member 50B, and the third retaining member 50C are stacked. According to this configuration, the first holding member 50A, the second holding member 50B, and the third holding member 50C are housed in a stacked state in the cover 50D, and these holding members are maintained in a fixed state relative to one another. Therefore, the postures of the first fuse element 10 and parts of the first terminal 30 and the second terminal 40 disposed between the holding members are stabilized.

[0121] In this embodiment, each of the first filling material 71 and the second filling material 72 is made of an elastic resin. 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, so that expansion / contraction and deformation due to the difference in thermal expansion between the first fuse element 10 and the insulating case 50 can be more effectively mitigated.

[0122] In this embodiment, the third filler 73 includes at least insulating fibers or silica sand. When the third filler 73 contains at least insulating fiber, the surface area of ​​the third filler 73 can be secured, and the surface area of ​​the entire third filler 73 can be easily increased compared to when the third filler 73 is plate-shaped. In addition, when the third filler 73 contains at least insulating fiber, there are more elements to capture the molten debris compared to when the third filler 73 is plate-shaped. Therefore, it is easier to prevent a sudden increase in the internal pressure of the protection element 1 caused by the molten debris entering the internal pressure buffering space 55. When the third filler 73 contains at least silica sand, the surface area can be secured for each particle of the silica sand, and the surface area of ​​the entire third filler 73 can be easily increased compared to when the third filler is in a plate shape. Therefore, it is easier to prevent a sudden increase in the internal pressure of the protection element 1 caused by molten debris entering the internal pressure buffering space 55.

[0123] In this embodiment, the flux 75 is applied to at least one surface of the first soluble conductor 12. According to this configuration, when an overcurrent flows, the first soluble conductor 12 is easily melted, and the overcurrent interruption speed can be improved.

[0124] In this embodiment, the insulating case 50 is made of a polyamide resin or a fluorine resin. According to this configuration, polyamide-based resin and fluororesin have high heat resistance and are difficult to burn. In particular, aliphatic polyamide is difficult to generate graphite even when burned. Therefore, by forming the insulating case 50 from aliphatic polyamide, graphite generation due to arc discharge when the first fuse element 10 melts can be suppressed, and the formation of a new current path can be more reliably prevented.

[0125] In the present embodiment, the first fuse element 10 includes the first fusible conductor 12 and the conductor, which are made of different materials, but the present invention is not limited to this. For example, the first fuse element 10 may be entirely made of Ag or Cu, or may be made mainly of Ag or Cu. In this case, the first fuse element 10 includes Ag or Cu. The first fuse element 10 may be a Cu element, an Ag element, a Cu alloy, or an Ag alloy.

[0126] The present invention is not limited to the above-described embodiment, and the configuration can be changed without departing from the spirit of the present invention, for example, as described below. In the drawings of other embodiments and modifications, the same components as those in the above-described embodiment are given the same reference numerals, and the following mainly describes the differences.

[0127] Second embodiment A protection element 201 according to a second embodiment of the present invention will be described with reference to Fig. 6 to Fig. 9. The protection element 201 of the second embodiment differs from the first embodiment described above mainly in that it includes a heating element 80 and a power supply member 81. In each drawing of this embodiment, components that are the same or substantially the same as those in the first embodiment may be denoted by the same reference numerals or names and descriptions thereof may be omitted.

[0128] 6 to 9, the protection element 201 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 current flow direction, a heating element 80, a power supply member 81 connected to the heating element 80, and an insulating case 250 that houses the first terminal 30 and a portion of the second terminal 40, the first fuse element 10, the heating element 80, and a portion of the power supply member 81.

[0129] The protective element 201 of this embodiment has, as a mechanism for interrupting the current path, an overcurrent interruption in which the first fuse element 10 melts to interrupt the current path when an overcurrent (current equal to or greater than a predetermined value) exceeding the rated current flows through the first fuse element 10, and an active interruption in which, when an abnormality other than an overcurrent occurs, a current is passed through the heating element 80 to cause it to generate heat, thereby melting the first fuse element 10 and interrupting the current path.

[0130] The heating element 80 is arranged so as to overlap the first fuse element 10 in the vertical direction. The heating element 80 contacts the first fuse element 10 in the vertical direction. The heating element 80 generates heat by the passage of electricity from the power supply member 81, and melts and blows at least a part of the first fuse element 10. Specifically, the heating element 80 is arranged so as to overlap the first soluble conductor 12 in the vertical direction, and is stacked in the vertical direction with the rear end of the first conductor 11 and the front end of the second conductor 13. The heating element 80 melts and blows at least a part of the first soluble conductor 12 by heat generated by the passage of electricity. In the following description, "melt and blow at least a part" may be abbreviated to "melt and blow".

[0131] In the illustrated example, the heating element 80 is plate-shaped, with a pair of plate surfaces facing the up-down direction. When viewed from the up-down direction, the heating element 80 has a rectangular plate shape with a larger left-right dimension than a front-rear dimension. The heating element 80 is disposed in a heating element housing portion 61 formed in the insulating case 250. That is, the heating element 80 is housed in the insulating case 250.

[0132] The heating element accommodating portion 61 is recessed from the surface of the insulating case 250 facing the first fuse element 10 of the second holding member 50B. In the example shown in the figure, the heating element accommodating portion 61 is recessed upward from the lower surface of the second holding member 50B. The heating element accommodating portion 61 is disposed at the center side in the front-rear direction in the second holding member 50B. The heating element accommodating portion 61 is a rectangular hole that is long in the left-right direction. In the example shown in the figure, the front-rear dimension of the conductor facing recess 60 is smaller than the front-rear dimension of the heating element accommodating portion 61. The vertical dimension (depth dimension) of the conductor facing recess 60 is smaller than the vertical dimension of the heating element accommodating portion 61.

[0133] Heating element 80 extends in a direction intersecting the current flow direction (approximately corresponding to the front-rear direction) in which current flows through first fuse element 10, and in the example shown in the figure, extends in a direction perpendicular to the current flow direction (i.e., the left-right direction). Although not shown, heating element 80 has an insulating substrate (substrate), a resistive layer laminated on the insulating substrate, a metal layer laminated on the insulating substrate and facing the first fuse element 10 side in the top-bottom direction, an insulating layer, and a heating element electrode.

[0134] For example, when it becomes necessary to cut off the current path due to an abnormality occurring in the external circuit that serves as the current path of the protective element 201, the heating element 80 is energized and heated by a current control element provided in the external circuit.

[0135] The power supply member 81 is a member that supplies power to the heating element 80. The power supply member 81 extends from the outside to the inside of the insulating case 250, and one end of the power supply member 81 is connected to a heating element electrode (not shown) of the heating element 80. For example, at least a part of the power supply member 81 is made of an electric wire (wiring member). Note that at least a part of the power supply member 81 is not limited to the above, and may be made of a conductive plate-shaped member or rod-shaped member, etc., although not particularly shown.

[0136] The insulating case 250 comprises a first retaining member 50A in which at least a first buffer space 51 is formed, a second retaining member 50B in which an internal pressure buffer space 55 is formed, a third retaining member 50C that covers the open surface 56 of the internal pressure buffer space 55, and a first cover 250D1 and a second cover 250D2 that are inserted respectively from both directions perpendicular to the stacking direction of the first retaining member 50A, the second retaining member 50B, and the third retaining member 50C. The first buffer space 51 may be formed in the second holding member 50B instead of the first holding member 50A.

[0137] Each of the first cover 250D1 and the second cover 250D2 is a cylinder extending in the front-rear direction. In the example shown in the figure, each of the first cover 250D1 and the second cover 250D2 is a cylinder opening in the front-rear direction. The first cover 250D1 and the second cover 250D2 have approximately the same length in the front-rear direction. The three holding members are housed in the first cover 250D1 and the second cover 250D2 in a state where they are combined side by side in the vertical direction. The first cover 250D1 and the second cover 250D2 hold the three holding members 50A, 50B, and 50C in a fixed state by adhesion or the like. The power supply member 81 extends in the left-right direction through a gap between the first cover 250D1 and the second cover 250D2. The first cover 250D1 and the second cover 250D2 may have different lengths in the front-rear direction.

[0138] In this embodiment, the leak hole and / or gap 254 is formed at a position different from the leak hole and / or gap 54 described above. In the example shown in the figure, two leak holes and / or gaps 254 are arranged at an interval in the front-rear direction. The leak holes and / or gaps 254 extend linearly along the up-down direction. The leak holes and / or gaps 254 extend linearly along the left-right direction. The leak holes and / or gaps 254 are arranged near the heating element 80. The leak holes and / or gaps 254 are arranged along the front and rear edges of the heating element 80 when viewed from the up-down direction. The left-right dimension of the leak hole and / or gap 254 is larger than the left-right dimension of the heating element 80. For example, the opening area of ​​the leak hole and / or gap 54, 254 (the total value of the cross-sectional area when each of the leak hole and / or gap 54, 254 is cut by a plane perpendicular to the up-down direction) is 20% or less of the length in the current-carrying direction of the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other in the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other, and there is no restriction outside the area where the insulating case 50 and the first fuse element 10 are adjacent to or in contact with each other. For example, the left-right dimension of the leak hole and / or gap 254 may be less than the left-right dimension of the heating element 80. For example, the leak hole and / or gap 54 may not be formed, and the leak hole and / or gap 254 may be formed. For example, the leak hole and / or gap 254 may be formed instead of the leak hole and / or gap 54, or the leak hole and / or gap 254 may be formed together with the leak hole and / or gap 54. The form (number, location, shape, opening area, etc.) of the leak holes and / or gaps 54, 254 is not limited to the above, and can be changed according to design specifications.

[0139] In the protective element 201 of the present embodiment described above, when an overcurrent exceeding the rated current (i.e., a current equal to or greater than a predetermined value) flows through the first fuse element 10, the first fuse element 10 heats up and melts down, thereby interrupting the current path. In addition, the protective element 201 is capable of interrupting the current path by passing a current through the heating element 80 to cause the heating element 80 to generate heat, thereby melting and melting the first fuse element 10 stacked on the heating element 80. According to the present embodiment, it is possible to provide a protective element 201 that can suppress the occurrence of a large-scale arc discharge when the first fuse element 10 melts down, and that can achieve both an overcurrent cutoff function and a cutoff function in response to a cutoff signal.

[0140] Third embodiment A protection element 301 according to a third embodiment of the present invention will be described with reference to Figures 10 and 11. The protection element 301 of the third embodiment differs from the first embodiment described above mainly in that it further includes a second fuse element 20 arranged in parallel with the first fuse element 10, and an insulating member 90. In each drawing of this embodiment, components that are the same or substantially the same as those in the first embodiment may be denoted by the same reference numerals or names and descriptions thereof may be omitted.

[0141] 10 and 11 , the protective element 301 includes a second fuse element 20 arranged in parallel with the first fuse element 10 and connected to the first terminal 30 and the second terminal 40, an insulating member 90 arranged between the first fuse element 10 and the second fuse element 20, and an insulating case 350 that houses a portion of the first terminal 30 and the second terminal 40, the first fuse element 10, the second fuse element 20, and the insulating member 90.

[0142] The second fuse element 20 is made of a metal plate-like member, a sheet-like member, or a metal foil. In the illustrated example, only one second fuse element 20 is provided, but this is not limited thereto. For example, two second fuse elements 20 may be provided side by side in the vertical direction, or three or more second fuse elements 20 may be provided side by side. For example, the installation mode of the second fuse element 20 can be changed according to the design specifications.

[0143] The second fuse element 20 has a third conductor 21, a second soluble conductor 22, and a fourth conductor 23 connected in series in the current flow direction (specifically, the current flow direction of the second fuse element 20). For example, the second soluble conductor 22 is made of a material having a lower melting temperature than each of the third conductor 21 and the fourth conductor 23. For example, the second soluble conductor 22 has a higher electrical resistivity than each of the third conductor 21 and the fourth conductor 23. The second soluble conductor 22 functions as a melting portion of the second fuse element 20 when an overcurrent is interrupted.

[0144] The second soluble conductor 22 is plate-shaped, sheet-shaped, or foil-shaped, and extends in a plane direction (XY plane direction) perpendicular to the vertical direction. In the example shown in the figure, the second soluble conductor 22 is a rectangular plate shape whose left-right dimension is larger than its front-rear dimension when viewed from the vertical direction. The second soluble conductor 22 is disposed in the center of the second fuse element 20 in the front-rear direction. In this embodiment, flux 75 is applied to at least one surface of the second soluble conductor 22.

[0145] For example, the second soluble conductor 22 is made of Sn (tin) or a metal mainly composed of Sn. Although not shown, the second soluble conductor 22 may be a laminate including a high melting point metal layer and a low melting point metal layer. For example, the second soluble conductor 22 is formed of the same material as the first soluble conductor 12. The second soluble conductor 22 may be formed of a material different from the first soluble conductor 12, not limited to the above. For example, the material of the second soluble conductor 22 can be changed according to the design specifications.

[0146] 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 metal plate-shaped member. In the example shown in the figure, each of the third conductor 21 and the fourth conductor 23 is a substantially rectangular plate shape whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction. In this embodiment, each of the third conductor 21 and the fourth conductor 23 is made of Ag or Cu, or a metal mainly composed of Ag or Cu.

[0147] The third conductor 21, the second soluble conductor 22, and the fourth conductor 23 are connected in series in this order to form a current path of the second fuse element 20. Each of the third conductor 21 and the fourth conductor 23 is connected to an end of the second soluble conductor 22 in the current direction (approximately the front-rear direction in the example shown in the figure) in which current flows through the second fuse element 20.

[0148] The third conductor 21 is connected to one end of the second soluble 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 soluble 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 soluble conductor 22. The fourth conductor 23 is connected to the other end of the second soluble 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 soluble 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 soluble conductor 22. The second soluble conductor 22 is arranged on the upper surface side of the third conductor 21 and the fourth conductor 23 and spans between them.

[0149] The first terminal 30 and the third conductor 21 are connected. 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 and the lower surface of the front end of the third conductor 21 are connected to each other. The second terminal 40 and the fourth conductor 23 are connected. 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 and the lower surface of the rear end of the fourth conductor 23 are connected to each other.

[0150] The third conductor 21 includes an inner plate portion 21A connected to the second soluble conductor 22, and a third buffer portion 25 arranged in the first buffer space 351 so as to be surrounded by the first filler 71 and to relieve physical stress. In the example shown in the figure, each of the first buffer portion 15 and the third buffer portion 25 is arranged in the first buffer space 351 so as to be surrounded by the first filler 71.

[0151] The inner plate portion 21A is a plate extending in a plane direction (XY plane direction) perpendicular to the up-down direction. The rear end portion of the inner plate portion 21A is connected to the front end portion of the second soluble conductor 22 by soldering or the like.

[0152] The third buffer portion 25 is disposed between the front end of the inner 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 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 soldering or the like.

[0153] In the illustrated example, the third buffer section 25 has a curved shape that is convex toward the top. In other words, the third buffer section 25 has a hat shape that protrudes upward when viewed from the left-right direction. The third buffer section 25 is not limited to the above, and may have a curved shape that is convex toward the bottom. For example, the third buffer section 25 may have a crank shape when viewed from the left-right direction. For example, the shape of the third buffer section 25 can be changed according to design specifications.

[0154] The fourth conductor 23 includes an inner plate portion 23A connected to the second soluble conductor 22, and a fourth buffer portion 26 arranged in the second buffer space 352 so as to be surrounded by the second filler 72 and mitigating physical stress. In the example shown in the figure, each of the second buffer portion 16 and the fourth buffer portion 26 is arranged in the second buffer space 352 so as to be surrounded by the second filler 72.

[0155] The inner plate portion 23A is a plate extending in a plane direction (XY plane direction) perpendicular to the up-down direction. The front end portion of the inner plate portion 23A is connected to the rear end portion of the second soluble conductor 22 by soldering or the like.

[0156] The fourth buffer portion 26 is disposed between the rear end of the inner 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 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 soldering or the like.

[0157] In the illustrated example, the fourth buffer section 26 has a curved shape that protrudes upward. In other words, the fourth buffer section 26 has a hat shape that protrudes upward when viewed from the left-right direction. The fourth buffer section 26 is not limited to the above, and may have a curved shape that protrudes downward. For example, the fourth buffer section 26 may have a crank shape when viewed from the left-right direction. For example, the shape of the fourth buffer section 26 can be changed according to design specifications.

[0158] The insulating member 90 is plate-shaped, with a pair of plate surfaces facing the up-down direction. In the example shown in the figure, the insulating member 90 is a rectangular plate whose left-right dimension is smaller than its front-rear dimension when viewed from the up-down direction. For example, the insulating member 90 is made of a resin having a tracking resistance index CTI of 500V or more. For example, the insulating member 90 is made of a polyamide-based resin material or a fluorine-based resin material. Examples of the resin material constituting the insulating member 90 are the same as those of the insulating case 50 (the cover 50D and each holding member) described above.

[0159] The insulating member 90 has a first opposing surface 91 that is in close proximity to or in contact with the first fuse element 10, and a second opposing surface 92 that is in close proximity to or in contact with the second fuse element 20. In the example shown in the figure, the lower surface of the insulating member 90 corresponds to the first opposing surface 91, and the upper surface of the insulating member 90 corresponds to the second opposing surface 92.

[0160] Although not shown, the insulating member 90 may have a slit portion that opens in the vertical direction and extends in the horizontal direction outside the fusible conductor in the front-rear direction. The slit portion extends in a direction perpendicular to the current flow direction (approximately the front-rear direction) in which current flows through the fuse elements 10, 20. When the slit portion is formed in the insulating member 90, the molten spatter that adheres to the first opposing surface 91 and the second opposing surface 92 of the insulating member 90 after the fuse elements 10, 20 are cut off becomes discontinuous at the slit portion, and the insulation resistance between the first terminal 30 and the second terminal 40 after the cutoff can be suitably increased.

[0161] In the insulating case 350, a first buffer space 351 is formed around the first buffer section 15 and the third buffer section 25, a second buffer space 352 is formed around the second buffer section 16 and the fourth buffer section 26, a first element accommodating space 353A is formed in a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10, a second element accommodating space 353B is formed in a portion other than the periphery of the third buffer section 25 and the periphery of the fourth buffer section 26 of the second fuse element 20, and an internal pressure buffering space 55 is formed which communicates with each of the first element accommodating space 353A and the second element accommodating space 353B via a leak hole and / or a gap 54. The insulating case 350 is configured to be in close proximity to or in contact with a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10, and a portion other than the periphery of the third buffer section 25 and the periphery of the fourth buffer section 26 of the second fuse element 20.

[0162] The insulating case 350 comprises a first retaining member 50A in which at least a first buffer space 351 is formed, a second retaining member 350B in which an internal pressure buffer space 55 is formed, a third retaining member 350C that covers an open surface 56 of the internal pressure buffer space 55, and a cover 50D that is inserted from a direction perpendicular to the direction in which the first retaining member 50A, the second retaining member 350B, and the third retaining member 350C are stacked.

[0163] The first holding member 50A is disposed below the first terminal 30, the second terminal 40, and the first fuse element 10. The first holding member 50A includes a terminal mounting surface 57, a terminal locking portion 58, and a conductor-facing recessed portion360.

[0164] The conductor facing recess 360 of the first holding member 50A is a recess that is recessed downward from the central portion of the upper surface of the first holding member 50A in the front-rear direction of the first fuse element 10. The conductor facing recess 360 of the first holding member 50A is a substantially rectangular hole that opens upward. The bottom surface of the conductor facing recess 360 is a flat surface facing upward and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. The bottom surface of the conductor facing recess 360 of the first holding member 50A faces the lower surface of the first fusible conductor 12.

[0165] The second holding member 350B is disposed above the first terminal 30, the second terminal 40, and the second fuse element 20. The upper surface of the second holding member 350B forms an open surface 56 of the internal pressure buffering space 55. The second holding member 350B includes a terminal pressing surface 59 and a conductor facing recess 360.

[0166] The conductor facing recess 360 of the second holding member 350B is a recess that is recessed upward from the central portion of the lower surface of the second holding member 350B in the front-rear direction of the second fuse element 20. The conductor facing recess 360 of the second holding member 350B is a substantially rectangular hole that opens downward. The bottom surface of the conductor facing recess 360 of the second holding member 350B is a flat surface facing downward and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. The bottom surface of the conductor facing recess 360 of the second holding member 350B faces the upper surface of the second fusible conductor 22.

[0167] The second holding member 350B is formed with a through hole 365 that opens in the up-down direction. The through hole 365 is disposed so as to overlap with each of the first buffer space 351 and the second buffer space 352 when viewed in the up-down direction.

[0168] The third holding member 350C has a protrusion 366 that protrudes downward from a portion that extends in a plane direction perpendicular to the up-down direction and enters the through-hole 365. The protrusion 366 is disposed so as to overlap with each of the first buffer space 351 and the second buffer space 352 when viewed from the up-down 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 that forms the through-hole 365.

[0169] The three holding members 50A, 350B, 350C are housed in the cover 50D in a state where they are combined in a vertical line with the insulating member 90 interposed therebetween. The cover 50D holds the three holding members 50A, 350B, 350C and the insulating member 90 in a fixed state by adhesion or the like.

[0170] When the first holding member 50A, the insulating member 90, the second holding member 350B, and the third holding member 350C are combined, a first buffer space 351 and a second buffer space 352 are formed in a portion surrounded by the first holding member 50A, the insulating member 90, the second holding member 350B, and the third holding member 350C. Each of the first buffer space 351 and the second buffer space 352 is formed by a part of a through hole 365 formed in the second holding member 350B, and is partitioned by a part of a protrusion 366 protruding from the third holding member 350C.

[0171] When the above-mentioned members 50A, 90, 350B, and 350C are combined, a first element accommodating space 353A is formed between the first holding member 50A and the insulating member 90. The first fuse element 10 is accommodated in the first element accommodating space 353A. When the above-mentioned members 50A, 90, 350B, and 350C are combined, a second element accommodating space 353B is formed between the second holding member 350B and the insulating member 90. The second fuse element 20 is accommodated in the second element accommodating space 353B.

[0172] A part of the upper surface of the first holding member 50A (a part of the surface facing the first element accommodating space 353A) is configured to be in close proximity to or in contact with the lower surface of a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10. A first opposing surface 91, which is the lower surface of the insulating member 90, is configured to be in close proximity to or in contact with the upper surface of a portion other than the periphery of the first buffer section 15 and the periphery of the second buffer section 16 of the first fuse element 10.

[0173] A part of the lower surface of the second holding member 350B (a part of the surface facing the second element accommodating space 353B) is configured to be in close proximity to or in contact with an upper surface of a 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 to be in close proximity to or in contact with a lower surface of a 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.

[0174] In a state in which the second holding member 350B and the third holding member 350C are combined, an internal pressure buffering space 55 is formed between the second holding member 350B and the third holding member 350C. The internal pressure buffering space 55 is a substantially rectangular parallelepiped space, and communicates with each of the first element accommodating space 353A and the second element accommodating space 353B via a leak hole and / or a gap 54.

[0175] In the illustrated example, the fillers 71 and 72 are filled in a part of the buffer spaces 351 and 352 (in other words, a part of the through hole 365) with a gap therebetween. For example, first, after the second holding member 350B is mounted on the first holding member 50A, the fillers 71 and 72 are put into the buffer spaces 351 and 352 through the through hole 365 before the third holding member 350C is mounted on the second holding member 350B. At this time, the amount of the fillers 71 and 72 to be put in may be adjusted taking into consideration the volume of the convex portion 366 of the third holding member 350C. Then, the convex portion 366 is inserted into the through hole 365, and the third holding member 350C is attached to the second holding member 350B. This allows the fillers 71 and 72 to be filled in a part of the buffer spaces 351 and 352 (in other words, a part of the through hole 365) with a gap therebetween.

[0176] The fillers 71 and 72 are not limited to being filled with gaps in parts of the buffer spaces 351 and 352, respectively, and may be filled completely without gaps in the buffer spaces 351 and 352, respectively. For example, the fillers 71 and 72 may be disposed in at least parts of the buffer spaces 351 and 352, respectively, so as to surround at least the buffer sections 15, 16, 25, and 26.

[0177] In the protective element 301 of the present 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 the first filler 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 the second filler 72. Therefore, gas, which is one of the sources of arc discharge that occurs when an overcurrent is interrupted, can be eliminated as much as possible around each of the first fuse element 10 and the second fuse element 20. This suppresses plasma that is generated by ionizing the gas, which is one of the sources of arc discharge, and suppresses arc discharge. In addition, physical stress is relieved in each of the first buffer portion 15 and the second buffer portion 16 of the first fuse element 10, and each of the third buffer portion 25 and the fourth buffer portion 26 of the second fuse element 20. Therefore, expansion / contraction and deformation due to the thermal expansion difference between the first fuse element 10, the second fuse element 20, the insulating member 90, and the insulating case 350 can be more effectively alleviated.

[0178] (Fourth embodiment) A protection element 401 according to a fourth embodiment of the present invention will be described with reference to Fig. 12. The protection element 401 of the fourth embodiment differs from the third embodiment described above mainly in that it includes a heating element 80 and a power supply member 81. In each drawing of this embodiment, components that are similar or substantially similar to those of the first to third embodiments described above may be denoted by the same reference numerals or names and descriptions thereof may be omitted.

[0179] 12, the protective element 401 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 current flow direction, a heating element 80, a power supply member 81 (not shown in FIG. 12) connected to the heating element 80, a second fuse element 20 arranged in parallel with the first fuse element 10 and connected to the first terminal 30 and the second terminal 40, an insulating member 90 arranged between the first fuse element 10 and the second fuse element 20, and an insulating case 450 that 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 member 81, and the insulating member 90.

[0180] The protective element 401 of this embodiment has, as a mechanism for interrupting the current path, an overcurrent interruption in which the fuse elements 10, 20 melt to interrupt the current path when an overcurrent (current equal to or greater than a predetermined value) exceeding the rated current flows through the fuse elements 10, 20, and an active interruption in which, when an abnormality other than an overcurrent occurs, a current is passed through the heating element 80, causing it to generate heat, thereby melting the fuse elements 10, 20 and interrupting the current path.

[0181] In this embodiment, the portions to which the soluble conductors 12, 22 are connected in each fuse element 10, 20 are opposite to those in the third embodiment described above. Specifically, in the first fuse element 10, the upper surface of the rear end of the first conductor 11 is connected to the lower surface of the front end of the first soluble conductor 12, and the upper surface of the front end of the second conductor 13 is connected to the lower surface of the rear end of the first soluble conductor 12. On the other hand, in the second fuse element 20, the lower surface of the rear end of the third conductor 21 is connected to the upper surface of the front end of the second soluble conductor 22, and the lower surface of the front end of the fourth conductor 23 is connected to the upper surface of the rear end of the second soluble conductor 22.

[0182] In the example of the figure, a pair of conductor facing recesses 460 are formed in the insulating member 90 in the up-down direction. The first soluble conductor 12 is arranged in the lower part of the pair of conductor facing recesses 460, and the second soluble conductor 22 is arranged in the upper part. Of the pair of conductor facing recesses 460, the lower part is a concave shape recessed upward from the central part in the front-rear direction of the lower surface of the insulating member 90, and the upper part is a concave shape recessed downward from the central part in the front-rear direction of the upper surface of the insulating member 90. Of the pair of conductor facing recesses 460, the bottom surface of the lower part faces the upper surface of the first soluble conductor 12, and the bottom surface of the upper part faces the lower surface of the second soluble conductor 22. The pair of conductor facing recesses 460 are arranged on the central side of the insulating member 90 in the front-rear direction.

[0183] The heating element 80 is provided in a pair in the vertical direction. The pair of heating elements 80 are arranged so as to overlap with each fuse element 10, 20 in the vertical direction. The lower one of the pair of heating elements 80 contacts the first fuse element 10 in the vertical direction, and the upper one contacts the second fuse element 20 in the vertical direction. The heating element 80 generates heat by the passage of electricity from the power supply member 81, and melts and blows at least a part of each fuse element 10, 20. Specifically, the lower one of the pair of heating elements 80 is arranged so as to overlap with the first soluble conductor 12 in the vertical direction and is stacked in the vertical direction with each of the rear end of the first conductor 11 and the front end of the second conductor 13, and the upper one is arranged so as to overlap with the second soluble conductor 22 in the vertical direction and is stacked in the vertical direction with each of the rear end of the third conductor 21 and the front end of the fourth conductor 23. The pair of heating elements 80 melt and blow at least a part of each soluble conductor 12, 22 by heat generated by the passage of electricity.

[0184] In the illustrated example, the lower of the pair of heat generating elements 80 is disposed in heat generating element housing portion 461 formed in first holding member 50A, and the upper of the pair of heat generating elements 80 is disposed in heat generating element housing portion 461 formed in second holding member 350B. That is, the pair of heat generating elements 80 are housed in insulating case 450.

[0185] In the protective element 401 of the present embodiment described above, when an overcurrent exceeding the rated current (i.e., a current equal to or greater than a predetermined value) flows through the fuse elements 10, 20, the fuse elements 10, 20 heat up and melt, thereby cutting off the current path. In addition, the protective element 401 is capable of cutting off the current path by passing a current through the heating element 80 to cause it to generate heat, thereby melting and cutting off the fuse elements 10, 20 stacked on the heating element 80. According to the present embodiment, it is possible to provide a protective element 401 that can suppress the occurrence of a large-scale arc discharge when the fuse elements 10, 20 melt, and that can achieve both an overcurrent cutoff function and a cutoff function by a cutoff signal.

[0186] The present invention may be combined with the various configurations described in the above-mentioned embodiments and modifications, and may include additions, omissions, substitutions, and other modifications, without departing from the spirit of the present invention. The present invention is not limited to the above-mentioned embodiments, but is limited only by the claims. [Explanation of symbols]

[0187] 1.201,301,401 Protection elements 10 First fuse element 11 First conductor 12 First fusible conductor 13 Second Conductor 15 1st 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 4th buffer section 30 1st terminal 40 2nd terminal 50,250,350,450 Insulation case 50A First holding member 50B Second holding member 50C Third retaining member 50D Cover 51,351 1st buffer space 52,352 2nd buffer space 53 Element storage space 54 Leaks and / or gaps 55 Internal pressure buffer space 56 Open surface 71 1st filler 72 Second filler 73 Third filler 75 Flux 80 Heating element 81 Power supply components 90 Insulating materials 91 First opposing surface 92 Second opposing surface 250D1 1st cover 250D2 2nd cover 254 Leaks and / or gaps 350B Second holding member 350C Third retaining member 353A First element storage space 353B Second element storage space

Claims

1. A first fuse element; a first terminal and a second terminal connected to both ends of the first fuse element in a current-carrying direction; an insulating case that accommodates the first terminal, a portion of the second terminal, and the first fuse element; The first fuse element has a first conductor and a first fusible conductor connected in series in a current-carrying direction of the first fuse element, the first conductor includes a first buffer portion that relieves physical stress; The insulating case has a first buffer space formed around the first buffer part, A first filler is disposed in the first buffer space so as to surround the first buffer portion, the insulating case is configured to be in close proximity to or in contact with a portion of the first fuse element other than the periphery of the first buffer portion; Protection element.

2. The first fuse element further includes a second conductor connected in series with the first fusible conductor in a current-carrying 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 and the first conductor are connected to each other, The second terminal and the second conductor are connected to each other, the second conductor includes a second buffer portion that relieves physical stress; The insulating case has a second buffer space formed around the second buffer part, Further comprising a second filler disposed in the second buffer space so as to surround the second buffer portion. The protection element according to claim 1 .

3. an element accommodating space is formed in the insulating case at a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space is formed in communication with the element accommodating space via a leak hole and / or a gap; Further comprising a third filler disposed in at least a portion of the internal pressure buffering space. The protection element according to claim 1 or 2.

4. each of the first conductor and the second conductor is a plate-shaped member made of metal; The insulating case is configured to be in close proximity to or in contact with a plate-like front surface portion and a plate-like back surface portion other than the periphery of the first buffer portion of the first conductor and the periphery of the second buffer portion of the second conductor. The protection element according to claim 2 .

5. Each of the first conductor and the second conductor is made of Ag or Cu, or a metal mainly composed of Ag or Cu. The protection element according to claim 2 or 4.

6. The first soluble conductor is made of Sn or a metal mainly composed of Sn. The protection element according to claim 1 or 2.

7. The first soluble conductor is a laminate including a high melting point metal layer and a low melting point metal layer. The protection element according to claim 1 or 2.

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

9. The insulating case is A first holding member in which at least the first buffer space is formed; a second holding member in which the internal pressure buffer space is formed; A third holding member that covers an open surface of the internal pressure buffering space; a cover that is inserted from a direction perpendicular to a direction in which the first holding member, the second holding member, and the third holding member are stacked. The protection element according to claim 3 .

10. Each of the first filler and the second filler is made of an elastic resin. The protection element according to claim 2 .

11. The elastic resin is a silicone resin or a photocurable acrylic resin. The protection element according to claim 10.

12. The third filler contains at least insulating fiber or silica sand. The protection element according to claim 3 .

13. The insulating fiber is a ceramic fiber paper. The protection element according to claim 12.

14. Flux is applied to at least one surface of the first fusible conductor. The protection element according to claim 1 or 2.

15. The insulating case is made of a polyamide resin or a fluorine resin. The protection element according to claim 1 or 2.

16. A first fuse element; a first terminal and a second terminal connected to both ends of the first fuse element in a current-carrying direction; A heating element; A power supply member connected to the heating element; an insulating case that accommodates the first terminal and a portion of the second terminal, the first fuse element, the heating element, and a portion of the power supply member; The first fuse element has a first conductor and a first fusible conductor connected in series in a current-carrying direction of the first fuse element, the first conductor includes a first buffer portion that relieves physical stress; The insulating case has a first buffer space formed around the first buffer part, A first filler is disposed in the first buffer space so as to surround the first buffer portion, the insulating case is configured to be in close proximity to or in contact with a portion of the first fuse element other than the periphery of the first buffer portion; Protection element.

17. The first fuse element further includes a second conductor connected in series with the first fusible conductor in a current-carrying 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 and the first conductor are connected to each other, The second terminal and the second conductor are connected to each other, the second conductor includes a second buffer portion that relieves physical stress; The insulating case has a second buffer space formed around the second buffer part, Further comprising a second filler disposed in the second buffer space so as to surround the second buffer portion. The protection element according to claim 16.

18. an element accommodating space is formed in the insulating case at a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space is formed in communication with the element accommodating space via a leak hole and / or a gap; Further comprising a third filler disposed in at least a portion of the internal pressure buffering space. The protection element according to claim 16 or 17.

19. each of the first conductor and the second conductor is a plate-shaped member made of metal; The insulating case is configured to be in close proximity to or in contact with a plate-like front surface portion and a plate-like back surface portion other than the periphery of the first buffer portion of the first conductor and the periphery of the second buffer portion of the second conductor. The protection element according to claim 17.

20. Each of the first conductor and the second conductor is made of Ag or Cu, or a metal mainly composed of Ag or Cu.

20. A protection element according to claim 17 or 19.

21. The first soluble conductor is made of Sn or a metal mainly composed of Sn. The protection element according to claim 16 or 17.

22. The first soluble conductor is a laminate including a high melting point metal layer and a low melting point metal layer. The protection element according to claim 16 or 17.

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

24. The insulating case is A first holding member in which at least the first buffer space is formed; a second holding member in which the internal pressure buffer space is formed; A third holding member that covers an open surface of the internal pressure buffering space; a first cover and a second cover that are inserted from both directions perpendicular to a direction in which the first holding member, the second holding member, and the third holding member are stacked, The protection element according to claim 18.

25. Each of the first filler and the second filler is made of an elastic resin. The protection element according to claim 17.

26. The elastic resin is a silicone resin or a photocurable acrylic resin. The protection element according to claim 25.

27. The third filler contains at least insulating fiber or silica sand. The protection element according to claim 18.

28. The insulating fiber is a ceramic fiber paper. The protection element according to claim 27.

29. Flux is applied to at least one surface of the first fusible conductor. The protection element according to claim 16 or 17.

30. The insulating case is made of a polyamide resin or a fluorine resin. The protection element according to claim 16 or 17.

31. a second fuse element disposed in parallel with the first fuse element and connected to the first terminal and the second terminal; an insulating member disposed between the first fuse element and the second fuse element, the insulating member having a first opposing surface adjacent to or in contact with the first fuse element and a second opposing surface adjacent to or in contact with the second fuse element; The second fuse element has a third conductor and a second fusible conductor connected in series in a current-carrying direction of the second fuse element, the third conductor is disposed in the first buffer space so as to be surrounded by the first filling material, and includes a third buffer portion that relieves physical stress; the insulating case is configured to be in close proximity to or in contact with a portion of the second fuse element other than the periphery of the third buffer portion; The protection element according to claim 1 .

32. The first fuse element further includes a second conductor connected in series with the first fusible conductor in a current-carrying 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 and the first conductor are connected to each other, The second terminal and the second conductor are connected to each other, the second conductor includes a second buffer portion that relieves physical stress; The insulating case has a second buffer space formed around the second buffer part, Further comprising a second filler disposed in the second buffer space so as to surround the second buffer portion. The protection element according to claim 31 .

33. The second fuse element further includes a fourth conductor connected in series with the second fusible conductor in the current-carrying 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 and the third conductor are connected; the second terminal and the fourth conductor are connected; The fourth conductor is disposed in the second buffer space so as to be surrounded by the second filling material, and includes a fourth buffer portion that relieves physical stress. The protection element according to claim 32.

34. a first element accommodating space is formed in the insulating case at a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space is formed in communication with the first element accommodating space via a leak hole and / or a gap; Further comprising a third filler disposed in at least a portion of the internal pressure buffering space. A protection element according to any one of claims 31 to 33.

35. a second element accommodating space is formed in the insulating case at a portion other than a periphery of the third buffer portion of the second fuse element, The second element accommodating space communicates with the internal pressure buffering space via the leak hole and / or the gap. The protection element of claim 34.

36. a second fuse element disposed in parallel with the first fuse element and connected to the first terminal and the second terminal; an insulating member disposed between the first fuse element and the second fuse element, the insulating member having a first opposing surface adjacent to or in contact with the first fuse element and a second opposing surface adjacent to or in contact with the second fuse element; The second fuse element has a third conductor and a second fusible conductor connected in series in a current-carrying direction of the second fuse element, the third conductor is disposed in the first buffer space so as to be surrounded by the first filling material, and includes a third buffer portion that relieves physical stress; the insulating case is configured to be in close proximity to or in contact with a portion of the second fuse element other than the periphery of the third buffer portion; The protection element according to claim 16.

37. The first fuse element further includes a second conductor connected in series with the first fusible conductor in a current-carrying 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 and the first conductor are connected to each other, The second terminal and the second conductor are connected to each other, the second conductor includes a second buffer portion that relieves physical stress; The insulating case has a second buffer space formed around the second buffer part, Further comprising a second filler disposed in the second buffer space so as to surround the second buffer portion.

37. The protection element of claim 36.

38. The second fuse element further includes a fourth conductor connected in series with the second fusible conductor in the current-carrying 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 and the third conductor are connected; the second terminal and the fourth conductor are connected; The fourth conductor is disposed in the second buffer space so as to be surrounded by the second filling material, and includes a fourth buffer portion that relieves physical stress.

38. The protection element of claim 37.

39. a first element accommodating space is formed in the insulating case at a portion other than the periphery of the first buffer portion of the first fuse element, and an internal pressure buffering space is formed in communication with the first element accommodating space via a leak hole and / or a gap; Further comprising a third filler disposed in at least a portion of the internal pressure buffering space.

39. A protection element according to any one of claims 36 to 38.

40. a second element accommodating space is formed in the insulating case at a portion other than a periphery of the third buffer portion of the second fuse element, The second element accommodating space communicates with the internal pressure buffering space via the leak hole and / or the gap.

40. The protection element of claim 39.

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