protective element

Abstract

To make large-scale arc discharge be less likely to occur, reduce the size and weight of an insulation case, and achieve both overcurrent cutoff dealing with high voltage and large current and a cutoff function by a cutoff signal.SOLUTION: A protection element has a fuse element 50, an insulation case 260, a first terminal 91, and a second terminal 92. The protection element further has: an insulation member 60 arranged in the vicinity of the fuse element 50 or in a state being in contact with the fuse element 50, and that is formed with an opening or a separation part; a shield member 220 that can move so as to divide the fuse element 50; pressing means 230 that presses the shield member 220; a locking member 270 locked between the insulation case 260 and the shield member 220 to restrict the movement of the shield member 220; a heater element 80 that heats and softens the locking member 270 or a fixing member; and a power feeding member 90. The insulation case 260 further houses the insulation member 60, the shield member 220, the pressing means 230, the locking member 270, the heater element 80, and a part of the power feeding member 90.SELECTED DRAWING: Figure 16

Description

Technical Field

[0004] , ,

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

Background Art

[0002] Conventionally, there is a fuse element that generates heat and melts to cut off the current path when a current exceeding the rating flows through the current path. A protection element (fuse element) having a fuse element is used in a wide range of fields from home appliances to electric vehicles. For example, lithium-ion batteries are used in a wide range of applications from mobile device applications to electric vehicles (EVs) and storage batteries, and are becoming larger in capacity. With the increase in the capacity of lithium-ion batteries, the voltage has become a high-voltage specification of several hundred volts, and a large current specification of several hundred amperes to several thousand amperes is required for the current.

[0003] For example, Patent Document 1 describes a fuse element mainly used for automotive electric circuits and the like, which includes two elements connected between terminal portions located at both ends and a fusing portion provided at a substantially central portion of the element. Patent Document 1 describes a fuse in which a pair of fuse elements is stored inside a casing and an arc extinguishing material is enclosed between the fuse element and the casing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In protective devices installed in high-voltage, high-current current paths, arc discharge is likely to occur if the fuse element melts. If a large-scale arc discharge occurs, the insulating case housing the fuse element may be destroyed. For this reason, metals with low resistance and high melting points, such as copper, are used as the material for the fuse element to suppress the occurrence of arc discharge. In addition, robust and highly heat-resistant materials such as ceramics are used as the material for the insulating case, and the size of the insulating case is also increased. Furthermore, conventional high-voltage, high-current (100V / 100A or more) current fuses only offered overcurrent protection; none combined this with a tripping signal function.

[0006] This invention has been made in view of the above circumstances, and aims to provide a protective element that makes it difficult for large arc discharges to occur when the fuse element blows, makes it possible to reduce the size and weight of the insulating case, and achieves both overcurrent interruption that can handle high voltage and high current and an interruption function that is triggered by an interruption signal. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides the following means.

[0008] [Aspect 1 of the present invention] A fuse element, an insulating case housing the fuse element, an insulating member having a first terminal and a second terminal, further positioned in close proximity to or in contact with the fuse element and having an opening or separation portion formed therein, a shielding member movable in the insertion direction and inserted into the opening or separation portion of the insulating member to separate the fuse element, a pressing means for pressing the shielding member in the insertion direction of the shielding member, a locking member that is locked between the insulating case and the shielding member and prevents the movement of the shielding member, and the locking member or front A protective element comprising a heating element that heats and softens a fixing member that fixes the locking member, and a power supply member that supplies current to the heating element, wherein the fuse element has a first end and a second end that face each other, the first terminal having one end connected to the first end and the other end exposed to the outside from the insulating case, the second terminal having one end connected to the second end and the other end exposed to the outside from the insulating case, and the insulating case further housing the insulating member, the shielding member, the pressing means, the locking member, the heating element, and a part of the power supply member.

[0009] [Aspect 2 of the present invention] The protective element according to Embodiment 1, wherein the heating element generates heat, causing the locking member or the fixing member to soften, and the pressing force of the pressing means causes the shielding member to move while separating from the locking member or the fixing member, and further, the shielding member moves over the opening or the separation portion of the insulating member to cut the fuse element, thereby interrupting the current flow to the fuse element.

[0010] [Aspect 3 of the present invention] The shielding member cuts the fuse element and shields the cut portions of the fuse element from each other in the direction of current flow of the fuse element, as described in embodiment 2.

[0011] [Aspect 4 of the present invention] The pressing means is a spring, the protective element according to any one of embodiments 1 to 3.

[0012] [Aspect 5 of the present invention] The protective element according to any one of embodiments 1 to 4, wherein at least one of the insulating member, the shielding member, and the insulating case is made of a material with a tracking resistance index CTI of 500V or higher.

[0013] [Aspect 6 of the present invention] The protective element according to any one of embodiments 1 to 5, wherein at least one of the insulating member, the shielding member, and the insulating case is formed of a resin material selected from the group consisting of polyamide resins and fluororesins.

[0014] [Aspect 7 of the present invention] The fuse element is a laminate comprising a low-melting-point metal layer and a high-melting-point metal layer, wherein the low-melting-point metal layer contains tin and the high-melting-point metal layer contains silver or copper, according to any one of embodiments 1 to 6.

[0015] [Aspect 8 of the present invention] The protective element according to embodiment 7, wherein the fuse element is a laminate 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 disposed between the high-melting-point metal layers.

[0016] [Aspect 9 of the present invention] The protective element according to any one of embodiments 1 to 8, wherein the fuse element is a single layer containing silver or copper.

[0017] [Aspect 10 of the present invention] The protective element according to any one of embodiments 1 to 9, wherein the fuse element has a fusible portion between the first end and the second end, and the cross-sectional area of ​​the fusible portion in the direction of current flow is smaller than the cross-sectional area of ​​the first end and the second end in the direction of current flow from the first end to the second end.

[0018] [Aspect 11 of the present invention] The fuse element has a first fusible conductor and a second fusible conductor having a melting point lower than that of the first fusible conductor, and the first fusible conductor and the second fusible conductor are connected in series upon energization, the protection element according to any one of Aspects 1 to 10.

[0019] 〔Aspect 12 of the present invention〕 The second fusible conductor is disposed between two of the first fusible conductors, the protection element according to Aspect 11.

[0020] 〔Aspect 13 of the present invention〕 Due to the heat generation of the heating element, the shielding member moves and the second fusible conductor is cut off, the protection element according to Aspect 11 or 12.

[0021] 〔Aspect 14 of the present invention〕 The insulating case has an inner bottom surface disposed in a state of being close to or in contact with the opposite side of the shielding member of the fuse element, and the inner bottom surface has a groove extending along the opening or the separation portion of the insulating member, and the tip of the shielding member in the insertion direction can be inserted into the groove, the protection element according to any one of Aspects 1 to 13.

[0022] 〔Aspect 15 of the present invention〕 A plurality of the fuse elements laminated in parallel in a direction perpendicular to the surface of the plate-shaped fuse element, and a plurality of the insulating members disposed in contact with or close to each other between the plurality of the fuse elements, and the openings or the separation portions of each of the plurality of the insulating members overlap each other when viewed from the vertical direction, and the shielding member can move within all of the openings or the separation portions, the protection element according to any one of Aspects 1 to 14.

[0023] 〔Aspect 16 of the present invention〕 The protective element according to embodiment 15, wherein the plurality of insulating members include insulating members disposed on the outside of the outermost layer on the shielding member side of the plurality of fuse elements, the insulating case has an inner bottom surface disposed in close proximity to or in contact with the outside of the outermost layer on the opposite side of the plurality of fuse elements from the shielding member, the inner bottom surface has a groove extending along the opening or separation portion of the insulating member, and the shielding member is movable within all of the openings or separation portions and within the groove.

[0024] [Aspect 17 of the present invention] A protective element according to any one of embodiments 1 to 16, comprising: a plurality of fuse elements stacked in parallel perpendicularly to the surface of a plate-shaped fuse element; and a plurality of insulating members arranged in contact with or in close proximity to the spaces between and outside the plurality of fuse elements, wherein the openings or separations of each of the plurality of insulating members overlap each other when viewed from a vertical direction, and the shielding member is movable within all of the openings or separations.

[0025] [Aspect 18 of the present invention] The protective element according to any one of embodiments 1 to 17, wherein the insulating case has at least two retaining members arranged on both sides of the fuse element in a direction perpendicular to the surface of the plate-shaped fuse element, and one or both of the two retaining members are formed integrally with the insulating member.

[0026] [Aspect 19 of the present invention] The locking member is sandwiched and locked between the insulating case and the shielding member in the insertion direction of the shielding member, and the dimension of the locking member in the insertion direction is greater than the dimension of the locking member in the direction toward the locking member, as viewed from the width direction perpendicular to the current flow direction of the fuse element and the insertion direction of the shielding member, or as viewed from the current flow direction. This is a protective element according to any one of embodiments 1 to 18.

[0027] [Aspect 20 of the present invention] The shielding member has a first stage portion facing the insertion direction of the shielding member, the insulating case has a second stage portion facing the opposite side from the first stage portion in the insertion direction, the pair of end faces of the locking member facing the insertion direction are sandwiched between the first stage portion and the second stage portion, and the first stage portion and the second stage portion do not overlap each other when viewed from the insertion direction, the protective element according to any one of embodiments 1 to 19. [Effects of the Invention]

[0028] According to the present invention, it is possible to reduce the size and weight of the insulating case, as large-scale arc discharges are less likely to occur when the fuse element blows, and a protective element is provided that can simultaneously perform overcurrent interruption for high voltage and high current, as well as interruption by an interruption signal. [Brief explanation of the drawing]

[0029] [Figure 1] This is a perspective view of a protective element according to a first reference example, which differs in some technical concepts from the present invention. [Figure 2] Figure 1 is a perspective view with a portion removed to reveal the inside of the protective element shown in Figure 1. [Figure 3] Figure 1 is an exploded perspective view of the protective element shown. [Figure 4] (a) is a schematic plan view showing the first terminal, the second terminal, and one soluble conductive sheet constituting the fuse element laminate; (b) is a schematic plan view showing the fuse element laminate, the second insulating member, the first terminal, and the second terminal; and (c) is a cross-sectional view along the line X-X' in the plan view shown in (b). [Figure 5] (a) is a cross-sectional view along the line V-V' in Figure 1, and (b) is an enlarged view of the vicinity of the locking member. [Figure 6] This is a cross-sectional view of the protective element in the state where the shielding member has cut the fuse element and lowered completely. [Figure 7] (a) is a cross-sectional view of a protective element having a modified locking member, and (b) is an enlarged view of the vicinity of the locking member. [Figure 8]This shows an example of the structure of a heating element. (a) is a top plan view, (b) is a top plan view of the insulating substrate before printing, (c) is a top plan view after printing the resistive layer, (d) is a top plan view after printing the insulating layer, (e) is a top plan view after printing the electrode layer, and (f) is a bottom plan view. [Figure 9] This is a perspective view of a protective element used to explain how to draw out the power supply component that supplies power to the heating element. (a) shows the case where two heating elements are connected in series, and (b) shows the case where two heating elements are connected in parallel. [Figure 10] This is a schematic diagram of a modified example of the first reference example, where (a) is a perspective view of the retaining member 10BB, which is a modified example of the retaining member 10B, and (b) is a perspective view of the retaining member 10BB, which is a modified example of the retaining member 10B, and the first insulating member 61A and the second insulating member 61B, which are modified examples of the first insulating member 60A and the second insulating member 60B. [Figure 11] (a) is a perspective view of the second insulating member 61B in a modified example, and (b) is a perspective view of the first insulating member 61A. [Figure 12] This is a schematic perspective view showing the inside of the protective element in the second reference example, with a portion removed to reveal the interior; (b) is a lower perspective view of the shielding member. [Figure 13] This is a cross-sectional view of the protective element according to the second reference example, corresponding to Figure 5(a). [Figure 14] This is a cross-sectional view of the protective element in the state where the shielding member has completely lowered and separated the fuse element. [Figure 15] This is a schematic perspective view showing the fuse element laminate, the first terminal and the second terminal installed on the first retaining member. [Figure 16] This is a cross-sectional view (a cross-sectional view perpendicular to the width direction) showing the protective element according to the embodiment. [Figure 17] This is a cross-sectional view (a cross-sectional view perpendicular to the width direction) showing a protective element according to the embodiment, representing the state in which the shielding member has completely lowered and separated the fuse element. [Figure 18] This is a schematic cross-sectional view (a cross-sectional view perpendicular to the width direction) showing a part of the protective element according to the embodiment. [Figure 19]This is a schematic cross-sectional view (a cross-sectional view perpendicular to the width direction) showing a part of the protective element according to the embodiment, representing a state in which the shielding member has moved downward. [Figure 20] This is a schematic cross-sectional view (a cross-sectional view perpendicular to the width direction) showing a part of the protective element according to a modified embodiment. [Figure 21] This is a schematic cross-sectional view (a cross-sectional view perpendicular to the width direction) showing a part of the protective element according to a modified embodiment, representing a state in which the shielding member has moved downward. [Figure 22] This is a cross-sectional view (XZ cross-sectional view) showing a part of the protective element according to a modified embodiment. [Figure 23] This is a schematic diagram of a fuse element according to a modified embodiment, and is a plan view corresponding to Figure 4(a). [Modes for carrying out the invention]

[0030] The following will describe in detail, with appropriate reference to the drawings, references to reference examples that differ in some technical concepts from the present invention. The drawings used in the following description may be enlarged for convenience to clearly illustrate the features, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc., exemplified in the following description are examples only, and the present invention is not limited to them. It is possible to modify and implement them as appropriate within the scope of achieving the effects of the present invention.

[0031] (Protective element (first reference example)) Figures 1 to 5 are schematic diagrams showing the protective element according to the first reference example. In the diagrams used in the following explanation, the direction indicated by X is the direction of current flow in the fuse element. The direction indicated by Y is perpendicular to the X direction and is also called the width direction. In this reference example, one side of the width direction (Y direction) corresponds to the -Y side and the other side corresponds to the +Y side. However, it is not limited to this, and one side of the width direction may correspond to the +Y side and the other side to the -Y side. The direction indicated by Z is perpendicular to the X and Y directions and is also called the thickness direction. The thickness direction may also be called the up and down direction. Of the up and down direction (Z direction), the upper side corresponds to the +Z side and the lower side corresponds to the -Z side. In this example, "upper" and "lower" are merely terms used to describe the relative positions of the parts, and the actual arrangement may differ from those indicated by these terms.

[0032] Figure 1 is a schematic perspective view showing a protective element relating to the first reference example. Figure 2 is a schematic perspective view showing the protective element shown in Figure 1 with a portion removed to reveal its internal structure. Figure 3 is a schematic exploded perspective view of the protective element shown in Figure 1. Figure 4(a) is a schematic plan view showing the first terminal, the second terminal, and one soluble conductive sheet constituting the fuse element laminate; (b) is a schematic plan view showing the fuse element laminate, the second insulating member, the first terminal, and the second terminal; and (c) is a cross-sectional view along the line X-X' in the plan view shown in (b). Figure 5(a) is a cross-sectional view along the line V-V' in Figure 1; and (b) is an enlarged view of the vicinity of the locking member.

[0033] The protective element 100 shown in Figures 1 to 5 comprises an insulating case 10, a fuse element laminate 40, a first insulating member 60A, a second insulating member 60B, a shielding member 20, a pressing means 30, a locking member 70, a heating element 80, power supply members 90a and 90b, a first terminal 91, and a second terminal 92. The first insulating member 60A and the second insulating member 60B may be simply referred to as insulating members 60A and 60B.

[0034] In the protective element 100 of this reference example, the current direction refers to the direction in which electricity flows during use (X direction), that is, the direction connecting the first terminal 91 and the second terminal 92. Note that the direction from the first terminal 91 to the second terminal 92 is sometimes called the second terminal 92 side (-X side), and the direction from the second terminal 92 to the first terminal 91 is sometimes called the first terminal 91 side (+X side). Furthermore, the cross-sectional area in the current direction refers to the area of ​​the plane (YZ plane) perpendicular to the current direction. In the protective element 100 shown in Figures 1 to 5, an example is shown where the first insulating member 60A and the second insulating member 60B have different configurations. However, the first insulating member 60A and the second insulating member 60B may also have the same configuration.

[0035] The protective element 100 in this reference example has, as a mechanism for interrupting the current path, an overcurrent interruption in which the soluble conductive sheet 50 (see Figure 4(c)) melts and interrupts the current path when an overcurrent exceeding the rated current flows through it, and an active interruption in which, when an abnormality other than an overcurrent occurs, current is passed through the heating element 80 to melt the locking member 70 that is suppressing the movement of the shielding member 20, and the shielding member 20, which is being pressed downward by the pressing means 30, moves, cutting the fuse element 50 and interrupting the current path.

[0036] (Insulating case) The insulating case 10 is approximately cylindrical in shape (the cross-section of the YZ plane is oval at any position in the X direction). The insulating case 10 consists of a cover 10A and a retaining member 10B. The cover 10A has an elongated cylindrical shape with openings at both ends. The inner edges of the openings of the cover 10A are chamfered inclined surfaces 21. The central part of the cover 10A is a housing section 22 in which the retaining member 10B is housed.

[0037] The retaining member 10B consists of a first retaining member 10Ba positioned on the lower side in the Z direction and a second retaining member 10Bb positioned on the upper side in the Z direction. As shown in Figure 3, terminal mounting surfaces 111 are provided at both ends (first end 10Baa, second end 10Bab) of the first holding member 10Ba in the direction of current flow (X direction). Furthermore, as shown in Figure 3, power supply member mounting surfaces 12 are provided at both ends (first end 10Baa, second end 10Bab) of the first holding member 10Ba. The position (height) of the power supply member mounting surface 12 in the Z direction is approximately the same height as the position (height) of the heating element 80, thereby shortening the routing distance of the power supply member 90.

[0038] An internal pressure buffer space 15 (see Figures 5(a) and 6) is formed inside the holding member 10B. The internal pressure buffer space 15 has the effect of suppressing the rapid rise in internal pressure of the protective element 100 caused by the gas generated by the arc discharge that occurs when the fuse element laminate 40 melts.

[0039] The cover 10A and the retaining member 10B are preferably made of a material with a tracking resistance index CTI (resistance to tracking (carbonized conductive path) failure) of 500V or higher. The tracking resistance index (CTI) can be determined by testing based on IEC 60112.

[0040] Resin materials can be used for the cover 10A and the retaining member 10B. Resin materials have a lower heat capacity and melting point than ceramic materials. For this reason, using a resin material as the material for the holding member 10B is preferable because it has the characteristic of weakening arc discharge due to gasification cooling (ablation), and when molten and scattered metal particles adhere to the holding member 10B, the surface of the holding member 10B deforms or the attached material aggregates, making it difficult to form conductive paths.

[0041] As the resin material, for example, polyamide resins or fluororesins can be used. The polyamide resin may be an aliphatic polyamide or a semi-aromatic polyamide. Examples of aliphatic polyamides include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of semi-aromatic polyamides include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. An example of a fluororesin is polytetrafluoroethylene. Furthermore, polyamide resins and fluororesins have high heat resistance and are not easily combustible. In particular, aliphatic polyamides do not easily generate graphite even when burned. For this reason, by using aliphatic polyamide to form the cover 10A and the retaining member 10B, it is possible to more reliably prevent the formation of a new current path by graphite generated by the arc discharge when the fuse element laminate 40 is blown.

[0042] (Fuse element stack) The fuse element laminate comprises a plurality of soluble conductive sheets arranged in parallel in the thickness direction (a plurality of soluble conductive sheets are sometimes collectively called a fuse element), and a plurality of first insulating members arranged between each of the plurality of soluble conductive sheets, and in close proximity to or in contact with the outside of the soluble conductive sheet located at the bottom of the plurality of soluble conductive sheets, and having a first opening or first separation portion formed therein. The fuse element laminate consists of fuse elements and first insulating members. The fuse element laminate 40 has six soluble conductive sheets 50a, 50b, 50c, 50d, 50e, and 50f arranged in parallel in the thickness direction (Z direction). Between each of the soluble conductive sheets 50a to 50f, first insulating members 60Ab, 60Ac, 60Ad, 60Ae, and 60Af are arranged. The first insulating members 60Aa to 60Af are arranged in close proximity to or in contact with each of the soluble conductive sheets 50a to 50f. In the close proximity state, it is preferable that the distance between the first insulating members 60Ab to 60Af and the soluble conductive sheets 50a to 50f is 0.5 mm or less, and more preferably 0.2 mm or less. Furthermore, a first insulating member 60Aa is positioned on the outside of the soluble conductor sheet 50a, which is located at the bottom of the soluble conductor sheets 50a to 50f. In addition, a second insulating member 60B is positioned on the outside of the soluble conductor sheet 50f, which is located at the top of the soluble conductor sheets 50a to 50f. The width (length in the Y direction) of the soluble conductor sheets 50a to 50f is narrower than the width of the first insulating members 60Aa to 60Af and the second insulating member 60B. The fuse element laminate 40 is an example of having six soluble conductive sheets, but it is not limited to six; any number of sheets is acceptable.

[0043] Each of the soluble conductive sheets 50a to 50f has a first end 51 and a second end 52 facing each other, and a cut end 53 located between the first end 51 and the second end 52. The first ends 51 of the bottom three soluble conductive sheets 50a to 50c, which are arranged in parallel in the thickness direction, are connected to the lower surface of the first terminal 91, and the first ends 51 of the top three soluble conductive sheets 50d to 50f are connected to the upper surface of the first terminal 91. In addition, the second ends 52 of the bottom three soluble conductive sheets 50a to 50c are connected to the lower surface of the second terminal 92, and the second ends 52 of the top three soluble conductive sheets 50d to 50f are connected to the upper surface of the second terminal 92. The connection positions of the soluble conductive sheets 50a to 50f to the first terminal 91 and the second terminal 92 are not limited to these. For example, all of the first end portions 51 of the soluble conductive sheets 50a to 50f may be connected to the upper surface of the first terminal 91, or to the lower surface of the first terminal 91. Similarly, all of the second end portions 52 of the soluble conductive sheets 50a to 50f may be connected to the upper surface of the second terminal 92, or to the lower surface of the second terminal 92.

[0044] Each of the soluble conductive sheets 50a to 50f may be a laminate containing a low-melting-point metal layer and a high-melting-point metal layer, or it may be a single layer. The laminate containing a low-melting-point metal layer and a high-melting-point metal layer may have a structure in which the low-melting-point metal layer is surrounded by the high-melting-point metal layer. The low-melting-point metal layer of the laminate contains Sn. The low-melting-point metal layer may be pure Sn or a Sn alloy. A Sn alloy is an alloy in which Sn is the main component. A Sn alloy is an alloy in which Sn has the highest content among the metals contained in the alloy. Examples of Sn alloys include Sn-Bi alloy, In-Sn alloy, and Sn-Ag-Cu alloy. The high-melting-point metal layer contains Ag or Cu. The high-melting-point metal layer may be pure Ag, pure Cu, an Ag alloy, or a Cu alloy. An Ag alloy is an alloy in which Ag has the highest content among the metals contained in the alloy, and a Cu alloy is an alloy in which Cu has the highest content among the metals contained in the alloy. The laminate may have a two-layer structure of a low-melting-point metal layer / high-melting-point metal layer, or it may have a three- or more multilayer structure with two or more high-melting-point metal layers, one or more low-melting-point metal layers, and low-melting-point metal layers arranged between high-melting-point metal layers.

[0045] In the case of a single layer, it contains either Ag or Cu. The single layer may be pure Ag, pure Cu, an Ag alloy, or a Cu alloy.

[0046] Each of the fusible conductive sheets 50a to 50f may have through holes 54 (54a, 54b, 54c) in the fused portion 53. In the example shown in the figure, there are three through holes, but there is no limit to the number. By having through holes 54, the cross-sectional area of ​​the fused portion 53 becomes smaller than the cross-sectional area of ​​the first end 51 and the second end 52. Because the cross-sectional area of ​​the fused portion 53 is smaller, if a large current exceeding the rating flows through each of the fusible conductive sheets 50a to 50f, the amount of heat generated in the fused portion 53 will increase, making the fused portion 53 more susceptible to melting. The configuration to make the fused portion 53 more susceptible to melting than the first end 51 and the second end 52 is not limited to through holes; other configurations such as narrowing the width or partially reducing the thickness are also possible. A perforated cut shape is also acceptable. Furthermore, in each of the soluble conductive sheets 50a to 50f, the cut portion 53, which is configured to be easily cut, is easily cut by the convex portion 20a of the shielding member 20.

[0047] The thickness of the soluble conductive sheets 50a to 50f is such that they are melted by overcurrent and physically cut by the shielding member 20. The specific thickness depends on the material and number of soluble conductive sheets 50a to 50f, as well as the pressing force (stress) of the pressing means 30. For example, if the soluble conductive sheets 50a to 50f are copper foils, the thickness can be in the range of 0.01 mm to 0.1 mm. If the soluble conductive sheets 50a to 50f are foils with an alloy mainly composed of Sn plated with Ag, the thickness can be in the range of 0.1 mm to 1.0 mm.

[0048] Each of the first insulating members 60Aa to 60Af consists of a first insulating piece 63a and a second insulating piece 63b facing each other with a gap (first separation section) 64 between them. Similarly, the second insulating member 60B consists of a third insulating piece 66a and a fourth insulating piece 66b facing each other with a gap (second separation section) 65 between them. In the illustrated example, the gaps 64 and 65 between the first insulating members 60Aa to 60Af and the second insulating member 60B are separation sections (first separation section, second separation section) that separate the members into two parts (first insulating piece 63a and second insulating piece 63b and third insulating piece 66a and fourth insulating piece 66b), but they may also be openings (first opening, second opening) through which the convex portion 20a of the shielding member 20 can move (pass). Note that the first separation section 64 and the second separation section 65 may simply be referred to as separation sections 64 and 65. Furthermore, the first opening and the second opening may simply be referred to as openings (see the modified first opening 64A and second opening 65A described later). The first insulating piece 63a and the second insulating piece 63b each have ventilation holes 67 on both ends in the Y direction to efficiently release the pressure rise associated with the arc discharge that occurs when the fuse element is interrupted into the pressing means housing space of the insulating case. In the illustrated example, the first insulating piece 63a and the second insulating piece 63b each have three ventilation holes 67 on both ends in the Y direction, but there is no limit to the number. The rising pressure generated by the arc discharge is efficiently released through the ventilation holes 67 and the gaps (not shown) at the four corners between the pressing means support portion 20b and the second holding member 10Bb into the space housing the pressing means 30 in the insulating case 10. As a result, the shielding operation of the shielding member 20 is performed smoothly, and the destruction of the first insulating members 60Aa~60Af and the second insulating member 60B is prevented. The gaps 64 and 65 are located opposite the cut portion 53, which is positioned between the first end 51 and the second end 52 of the soluble conductive sheets 50a to 50f. In other words, the first insulating members 60Aa to 60Af and the second insulating member 60B are separated at a position opposite the cut portion 53 of the soluble conductive sheets 50a to 50f.

[0049] The first insulating members 60Aa to 60Af and the second insulating member 60B are preferably made of a material with a tracking resistance index CTI of 500V or higher. Resin materials can be used for the first insulating members 60Aa to 60Af and the second insulating member 60B. Examples of resin materials are the same as those for the cover 10A and the retaining member 10B.

[0050] The fuse element laminate 40 can be manufactured, for example, as follows: Using a jig that has positioning recesses corresponding to protrusions provided on the first insulating members 60Aa to 60Af and the second insulating member 60B, and positioning fixing parts for the first terminal 91 and the second terminal 92, the soluble conductive sheets 50a to 50f and the first insulating members 60Ab to 60Af are alternately stacked in the thickness direction on the first insulating member 60Aa, and the second insulating member 60B is placed on the upper surface of the soluble conductive sheet 50f positioned at the top to obtain a laminate.

[0051] (Shielding material) The shielding member 20 has a convex portion 20a facing the fuse element stack 40 side and a pressing means support portion 20b having a recess 20ba that accommodates and supports the lower part of the pressing means 30. The shielding member 20 is subjected to downward pressure from the pressing means 30, and its downward movement is restricted by the locking member 70. Therefore, when the locking member 70 is heated by the heat generated by the heating element 80 and softens to a temperature above its softening temperature, the shielding member 20 becomes able to move downward. At this time, depending on the type of material and the heating conditions, the softened locking member 70 may be physically cut by the shielding member 20, thermally melted, or subjected to a combination of physical cutting and thermal melting by the shielding member 20. When the downward movement restraint by the locking member 70 is released, the shielding member 20 moves downward and physically cuts the soluble conductive sheets 50a to 50f. In the shielding member 20, the tip 20aa of the convex portion 20a is pointed, making it easy to cut the soluble conductive sheets 50a to 50f. Figure 6 shows a cross-sectional view of the protective element in the state where the shielding member 20 has moved through the gaps 64 and 65 of the fuse element laminate 40, and the convex portion 20a has cut through the soluble conductive sheets 50a, 50b, 50c, 50d, 50e, and 50f, with the shielding member 20 fully lowered.

[0052] As the shielding member 20 moves down through the gaps 65 and 64 of the fuse element stack 40, the convex portion 20a of the shielding member 20 sequentially cuts the fusible conductive sheets 50f, 50e, 50d, 50c, 50b, and 50a. The cut surfaces are shielded and insulated from each other by the convex portion 20a, and the current path through each fusible conductive sheet is physically and reliably blocked. As a result, the arc discharge is quickly extinguished. Furthermore, when the shielding member 20 moves through the gaps 65 and 64 in the fuse element stack 40 and is fully lowered, the pressing means support portion 20b of the shielding member 20 presses the fuse element stack 40 from the second insulating member 60B, causing the fusible conductor sheet to be in close contact with the first insulating members 60Aa to 60Af and the second insulating member 60B. As a result, there is no longer any space between them where arc discharge can continue, and the arc discharge is reliably extinguished.

[0053] The thickness (length in the X direction) of the convex portion 20a is smaller than the width in the X direction of the gaps 64 and 65 between the first insulating members 60Aa to 60Af and the second insulating member 60B. This configuration allows the convex portion 20a to move downward in the Z direction through the gaps 64 and 65. For example, if the soluble conductive sheets 50a to 50f are copper foil, the difference between the thickness of the convex portion 20a and the width of the gaps 64 and 65 in the X direction can be, for example, 0.05 to 1.0 mm, and preferably 0.2 to 0.4 mm. If the difference is 0.05 mm or more, even if the end of the soluble conductive sheet 50a to 50f with a minimum cut thickness of 0.01 mm gets caught in the gap between the first insulating member 60Aa to 60Af and the second insulating member 60B and the convex portion 20a, the movement of the convex portion 20a becomes smoother, and the arc discharge is extinguished more quickly and reliably. This is because if the above difference is 0.05 mm or more, the convex portion 20a is less likely to get caught. Also, if the above difference is 1.0 mm or less, the gaps 64 and 65 function as guides for the movement of the convex portion 20a. Therefore, displacement of the convex portion 20a, which moves when the soluble conductive sheets 50a to 50f are cut, is prevented, and the arc discharge is extinguished more quickly and reliably. If the soluble conductive sheets 50a to 50f are foils in which an alloy mainly composed of Sn is plated with Ag, the difference between the thickness of the convex portion 20a and the width of the gaps 64 and 65 in the X direction can be, for example, 0.2 to 2.5 mm, and preferably 0.22 to 2.2 mm.

[0054] The width (length in the Y direction) of the convex portion 20a is wider than the width of the soluble conductive sheets 50a to 50f of the fuse element laminate 40. This configuration makes it possible for the convex portion 20a to cut each of the soluble conductive sheets 50a to 50f.

[0055] The length L in the Z direction of the convex portion 20a is such that, when it is fully lowered in the Z direction, the tip 20aa of the convex portion 20a reaches below the first insulating member 60Aa, which is located at the bottom of the first insulating members 60Aa to 60Af in the Z direction. When the convex portion 20a is lowered below the first insulating member 60Aa, which is located at the bottom, it is inserted into the insertion hole 14 formed in the inner bottom surface 13 of the holding member 10Ba. This configuration allows the convex portion 20a to cut through each of the soluble conductive sheets 50a to 50f.

[0056] (Pressing means) The pressing means 30 is housed in the recess 20ba of the shielding member 20 while pressing the shielding member 20 downward in the Z direction.

[0057] As the pressing means 30, known means capable of applying elastic force, such as a spring or rubber, can be used. In the protective element 100, a spring is used as the pressing means 30. The spring (pressing means) 30 is held in a compressed state in the recess 20ba of the shielding member 20.

[0058] As the spring material used for the pressing means 30, any known material can be used. The spring used as the pressing means 30 may be cylindrical or conical. Using a conical spring allows for a shorter contraction length, thereby suppressing the height during pressing and enabling miniaturization of the protective element. Furthermore, multiple conical springs can be stacked to increase the stress. When a conical spring is used as the pressing means 30, the side with the smaller outer diameter may be positioned toward the respective cut portions 53 of the soluble conductive sheets 50a to 50f, or the side with the larger outer diameter may be positioned toward the respective cut portions 53 of the soluble conductive sheets 50a to 50f. When a conical spring is used as the pressing means 30, by positioning the smaller outer diameter side toward the respective melted (cut) portions 53 of the soluble conductive sheets 50a to 50f, for example, when the spring is made of a conductive material such as metal, the continuation of the arc discharge that occurs when the melted portions 53 of the soluble conductive sheets 50a to 50f are cut can be suppressed more effectively. This is because it becomes easier to ensure a distance between the location where the arc discharge occurs and the conductive material forming the spring. Furthermore, if a conical spring is used as the pressing means 30, and the side with the larger outer diameter is positioned toward the respective cut portions 53 of the soluble conductive sheets 50a to 50f, the elastic force can be uniformly applied from the pressing means 30 to the shielding member 20, which is preferable.

[0059] (locking member) The locking member 70 bridges the gap 65 in the second insulating member 60B, suppressing the movement of the shielding member 20. The protective element 100 includes three locking members 70 (70A, 70B, 70C), but is not limited to three. The locking member 70A is placed (inserted) into grooves 60Ba1 and 60Ba2 of the second insulating member 60B, the locking member 70B is placed (inserted) into grooves 60Bb1 and 60Bb2 of the second insulating member 60B, and the locking member 70C is placed (inserted) into grooves 60Bc1 and 60Bc2 of the second insulating member 60B. Furthermore, the tip 20aa of the convex portion 20a of the shielding member 20 has a groove corresponding to the shape and position of the locking member 70 (see Figure 12(b)), and this groove stably holds the locking member 70 by gripping it.

[0060] The three locking members 70A, 70B, and 70C have the same shape. The shape of locking member 70A can be described using a diagram. It has a support portion 70Aa that rests and is supported in a groove formed in the second insulating member 60B, and a projection portion 70Ab that extends downward from the support portion, with its tip 70Aba approaching or contacting the uppermost soluble conductive sheet 50f. While all locking members 70 have the same shape, some may have different shapes.

[0061] Heating elements 80A and 80B are placed on top of locking members 70A, 70B, and 70C. When current is passed through the heating elements 80A and 80B, they generate heat, which is transferred to the locking members 70, causing the locking members 70 to rise in temperature and soften at a temperature above the softening temperature. Here, the softening temperature refers to the temperature or temperature range at which the solid and liquid phases are mixed or coexist. When the locking members 70 reach a temperature above the softening temperature, they become soft enough to deform under external force. The softened locking member 70 becomes more easily cut by the convex portion 20a of the shielding member 20, which is pressed by the pressing force of the pressing means 30. When the locking member 70 is cut, the convex portion 20a of the shielding member 20 is inserted downward in the Z direction through the gaps 65 and 64. As the convex portion 20a is inserted downward in the Z direction through the gaps 65 and 64, it cuts through the soluble conductive sheet as it advances and reaches its lowest position. In this way, the convex portion 20a shields the soluble conductive sheet 50a to 50f from the first terminal 91 side and the second terminal 92 side with its cut portion 53. This allows the arc discharge generated when the soluble conductive sheet 50a to 50f is cut to be extinguished quickly and reliably. The heat generated by the heating elements 80A and 80B heats the soluble conductive sheet 50f via the locking member 70, and further heats the other soluble conductive sheets, making the soluble conductive sheets 50a to 50f easily cut. Depending on the magnitude of the heat generated by the heating elements 80A and 80B, the soluble conductive sheet 50f may also be thermally melted. In this case, the convex portion 20a continues to advance and reaches the lowest position.

[0062] In the locking member 70, the protruding portion 70Ab is in contact with the soluble conductive sheet 50f. Therefore, when an overcurrent exceeding the rated current flows through the soluble conductive sheet, the locking member 70 in contact with the soluble conductive sheet 50f heats up and softens at a temperature above its softening temperature. Furthermore, if a large overcurrent flows and the soluble conductive sheet 50f melts instantaneously, the resulting arc discharge will also flow to the locking member 70, causing the locking member 70 to soften at a temperature above its softening temperature. The softened locking member 70 becomes more easily cut by the convex portion 20a of the shielding member 20, which is pressed by the pressing force of the pressing means 30. When the locking member 70 is cut, the convex portion 20a of the shielding member 20 is inserted downward in the Z direction through the gaps 65 and 64. In this case, the soluble conductive sheet is thermally melted due to an overcurrent exceeding the rated current, and the convex portion 20a is inserted downward in the Z direction through the gaps 65 and 64. At this time, the convex portion 20a shields the soluble conductive sheets 50a to 50f from the first terminal 91 side and the second terminal 92 side at its melted portion. This allows the arc discharge generated when the soluble conductive sheets 50a to 50f are cut to be extinguished quickly and reliably. Even if the soluble conductive sheet has not yet been thermally cut, as the convex portion 20a is inserted downward in the Z direction through the gaps 65 and 64, the convex portion 20a cuts through the soluble conductive sheet as it advances and reaches the lowest position. In this way, the convex portion 20a shields the soluble conductive sheet 50a to 50f from the first terminal 91 side and the second terminal 92 side at its cut portion. This allows the arc discharge that occurs when the soluble conductive sheet 50a to 50f is cut off to be extinguished quickly and reliably.

[0063] Figure 7(a) shows a protective element having a locking member 71, which is a modified example of the locking member 70. Figure 7(b) is an enlarged view of the vicinity of the locking member 71. The locking member 71 has only a support portion 71Aa that is placed and supported in a groove formed in the second insulating member 60B, and does not have a protruding portion that contacts the soluble conductive sheet 50f.

[0064] Since the locking member 71 does not have a portion that contacts the soluble conductive sheet 50f, it is not softened even if an overcurrent exceeding the rated current flows through the soluble conductive sheet, and is softened only by the heating element 80. However, in the event of an arc discharge due to high voltage, the arc discharge reaches the locking member 71 and melts the locking member 71, and the convex portion 20a shields the soluble conductive sheets 50a to 50f from the first terminal 91 side to the second terminal 92 side at the melted portion.

[0065] The materials of the locking members 70 and 71 can be the same as those of the soluble conductive sheet, but it is preferable that they be laminates containing a low-melting-point metal layer and a high-melting-point metal layer, as they soften rapidly when the heating element 80 is energized. For example, an alloy mainly composed of Sn with a melting point of 217°C can be used, plated with Ag with a melting point of 962°C.

[0066] (heating element) The heating element 80 is placed so as to be in contact with the upper surface of the locking member 70. By passing an electric current through the heating element 80, it generates heat, which heats the locking member 70, causing it to soften and melt. The melting of the locking member 70 causes the shielding member 20, which is being pressed downward in the Z direction by the pressing means 30, to be inserted into the gap in the fuse element laminate 40, cutting the fusible conductive sheet 50 and shielding the fuse element laminate 40 to the first terminal 91 side and the second terminal 92 side.

[0067] The protective element 100 includes two heating elements 80 (80A, 80B), but is not limited to two. Figure 8 shows a schematic diagram of the heating element 80. Figure 8(a) is a plan view of the front surface (the side facing the pressing means 30) of the heating element 80, Figure 8(b) is a plan view of the insulating substrate, and Figures 8(c) to (e) are transparent plan views showing the three layers on the front side of the insulating substrate stacked in order, with the lower layers visible. Figure 8(c) is a plan view of the state in which a resistive layer is stacked on the insulating substrate, (d) is a state in which an insulating layer is further stacked on (c), and (e) is a state in which an electrode layer is further stacked on (d). Figure 8(f) is a plan view of the back surface (the side facing the fuse element stack 40) of the heating element 80. Each heating element 80A and 80B comprises two resistive layers 80-1 (80-1a, 80-1b) arranged parallel and spaced apart on the front surface 80-3A (the side facing the pressing means 30) of the insulating substrate 80-3, an insulating layer 80-4 covering the resistive layers 80-1, heating element electrodes 80-5a and 80-5b formed on the insulating substrate 80-3 and electrically connected to both ends of the resistive layer 80-1a, heating element electrodes 80-5c and 80-5d electrically connected to both ends of the resistive layer 80-1b, and an electrode layer 80-2 (80-2a, 80-2b) formed on the back surface 80-3B (the side facing the fuse element laminate 40) of the insulating substrate 80-3. The resistive layer is provided in two places for each of the 80A and 80B heat-generating elements. However, this is a fail-safe design that allows for mounting even when rotated 180 degrees, and two layers are not strictly necessary. The resistive layer 80-1 is made of a conductive material that generates heat when current is applied, such as nichrome, W, Mo, Ru, etc., or a material containing these. The resistive layer 80-1 is formed by mixing powdered alloys or compositions or compounds of these materials with a resin binder, etc., to form a paste, and then forming a pattern on the insulating substrate 80-3 using screen printing technology and firing it. The insulating substrate 80-3 is an insulating substrate such as alumina, glass ceramics, mullite, or zirconia. The insulating layer 80-4 is provided to protect the resistive layer 80-1. As the material for the insulating layer 80-4, insulating materials such as ceramics or glass can be used. The insulating layer 80-4 can be formed by applying a paste of insulating material and firing it. The heating element electrodes 80-5a to 5d on the front surface and the electrode layers 80-2a to 5b on the back surface of heating elements 80A and 80B are electrically insulated by the insulating substrate 80-3. The heating elements 80A and 80B are not limited to those shown in Figure 8; known heating elements can be used.

[0068] The heating elements 80A and 80B are energized and heated by a current control element provided in the external circuit when it becomes necessary to interrupt the power supply path due to an abnormality in the external circuit that serves as the power supply path for the protection element 100.

[0069] (Power supply component) Figure 9 is a perspective view of a protective element illustrating a method for drawing out the power supply member that supplies power to the heating elements 80A and 80B. (a) shows the case where the heating elements 80A and 80B are connected in series, and (b) shows the case where the heating elements 80A and 80B are connected in parallel. In this reference example, at least a part of the power supply member is made up of an electric wire (wiring member). However, it is not limited to this, and although not specifically shown, at least a part of the power supply member may be made up of conductive plate-shaped members, rod-shaped members, etc. In Figure 9(a), the power supply member 90a is connected to the heating element electrode 80-5c of the heating element 80A (see Figure 8), the power supply member 90b is connected to the heating element electrode 80-5a of the heating element 80B (see Figure 8), and the power supply member 90A is connected to the heating element electrode 80-5d of the heating element 80A (see Figure 8) and the heating element electrode 80-5b of the heating element 80B (see Figure 8). In addition, the electrode layer 80-2 of the heating element 80A is connected to the electrode layer 80-2 of the heating element 80B via the locking members 70 (70A, 70B, 70C). In this configuration, power is supplied to the heating elements 80A and 80B via the path "power supply member 90a ~ heating element electrode 80-5c of heating element 80A ~ resistance layer 80-1a of heating element 80A ~ heating element electrode 80-5d of heating element 80A ~ power supply member 90A ~ heating element electrode 80-5b of heating element 80B ~ resistance layer 80-1b of heating element 80B ~ heating element electrode 80-5a of heating element 80B ~ power supply member 90b", causing the heating elements 80A and 80B to heat up. This heat melts the locking member 70 (70A, 70B, 70C), and the shielding member 20 is inserted into the gaps 64 and 65 of the fuse element laminate 40. When the shielding member 20 is inserted into the gaps 64 and 65 of the fuse element laminate 40, the power supply member 90A is cut, the power supply to the heating elements 80A and 80B is interrupted, and the heating of the heating elements 80A and 80B stops. In Figure 9(b), the power supply member 90c is connected to the heating element electrode 80-5c of the heating element 80A, and the power supply member 90e is connected to the heating element electrode 80-5d of the heating element 80A. Furthermore, the power supply member 90d is connected to the heating element electrode 80-5a of the heating element 80B, and the power supply member 90f is connected to the heating element electrode 80-5b (see Figure 8). In this configuration, a first path "power supply member 90c ~ heating element electrode 80-5c of heating element 80A ~ resistive layer 80-1a of heating element 80A ~ heating element electrode 80-5d of heating element 80A ~ power supply member 90e" and a second path "power supply member 90d ~ heating element electrode 80-5a of heating element 80B ~ resistive layer 80-1b of heating element 80B ~ heating element electrode 80-5b of heating element 80B ~ power supply member 90f" are configured in parallel. Power is supplied through the first and second paths to heat the heating elements 80A and 80B. This heat melts the locking members 70 (70A, 70B, 70C), and the shielding member 20 is inserted into the gaps 64 and 65 of the fuse element stack 40. In this configuration, the power supply to the heating elements 80A and 80B is not interrupted because the shielding member 20 is inserted into the gaps 64 and 65 of the fuse element stack 40, and the heating of the heating elements 80A and 80B continues. Therefore, by appropriately stopping the supply of power to the current control element by separate system control (timer, etc.), the heating of the heating elements 80A and 80B of the protection element 100 after the interruption can be stopped.

[0070] (1st terminal, 2nd terminal) The first terminal 91 has one end connected to the first end 51 of the soluble conductor sheets 50a to 50f, and the other end exposed to the outside of the insulating case 10. The second terminal 92 has one end connected to the second end 52 of the soluble conductor sheets 50a to 50f, and the other end exposed to the outside of the insulating case 10.

[0071] The first terminal 91 and the second terminal 92 may be substantially the same shape, or they may have different shapes. The thickness of the first terminal 91 and the second terminal 92 is not particularly limited, but may be in the range of 0.3 mm or more and 1.0 mm or less. The thickness of the first terminal 91 and the thickness of the second terminal 92 may be the same or different.

[0072] The first terminal 91 is provided with an external terminal hole 91a. The second terminal 92 is provided with an external terminal hole 92a. Of the external terminal holes 91a and 92a, one is used to connect to the power supply side, and the other is used to connect to the load side. Alternatively, the external terminal holes 91a and 92a may be used to connect to the current-carrying path inside the load. The external terminal holes 91a and 92a can be through holes that are approximately circular in plan view.

[0073] The first terminal 91 and the second terminal 92 can be made of, for example, copper, brass, nickel, or the like. From the viewpoint of increasing rigidity, brass is preferable for the material of the first terminal 91 and the second terminal 92, and from the viewpoint of reducing electrical resistance, copper is preferable. The first terminal 91 and the second terminal 92 may be made of the same material or of different materials.

[0074] (Manufacturing method for protective elements) The protective element 100 in this reference example can be manufactured as follows. First, the fuse element laminate 40, positioned using a jig, and the first terminal 91 and second terminal 92 are prepared. Then, the first end 51 of each of the fusible conductive sheets 50a to 50f of the fuse element laminate 40 are connected to the first terminal 91 by soldering. Furthermore, the second end 52 and the second terminal 92 are connected by soldering. Known solder materials can be used for soldering, and it is preferable to use a solder mainly composed of Sn from the viewpoint of resistivity, melting point, and environmentally friendly lead-free materials. The connection between the first end 51 and the first terminal 91 of the soluble conductive sheets 50a to 50f, and the connection between the second end 52 and the second terminal 92 of the soluble conductive sheets 50a to 50f, is not limited to soldering; known joining methods such as welding may also be used.

[0075] Next, prepare the locking members 70A, 70B, and 70C. Place each of the locking members 70A, 70B, and 70C in the grooves 60Ba1 and 60Ba2, grooves 60Bb1 and 60Bb2, and grooves 60Bc1 and 60Bc2 of the second insulating member 60B shown in Figure 3. Alternatively, a jig with the same shape as the second insulating member 60B may be used.

[0076] Next, prepare the heating elements 80A and 80B and solder paste shown in Figures 8(a) and 8(b). Then, apply an appropriate amount of solder paste to the connection points between the locking members 70A, 70B, and 70C and the heating elements 80A and 80B, and then, as shown in Figure 9(a), position the heating elements 80A and 80B in the designated locations on the second insulating member 60B. The back sides of the heating elements 80A and 80B are placed on top of the locking members 70A, 70B, and 70C. Heat in an oven or reflow oven and solder the locking members 70A, 70B, and 70C to the heating elements 80A and 80B.

[0077] Next, prepare the power supply members 90a, 90b, and 90A. Place power supply member 90a on the power supply member mounting surface 12 and connect it to the heating element electrode 80-5c of heating element 80A by soldering. Also, place power supply member 90b on the power supply member mounting surface 12 and connect it to the heating element electrode 80-5a of heating element 80B by soldering. Furthermore, connect power supply member 90A to the heating element electrode 80-5d of heating element 80A and the heating element electrode 80-5b of heating element 80B by soldering. The power supply members 90a, 90b, and 90A and the heating elements 80A and 80B may also be connected by welding, and known joining methods can be used.

[0078] Next, the second holding member 10Bb, the shielding member 20, and the pressing means 30 are prepared. Then, the pressing means 30 is placed in the recess 20ba of the shielding member 20 and housed in the second holding member 10Bb.

[0079] Next, the locking members 70A, 70B, and 70C are fitted into grooves provided at the tip 20aa of the shielding member 20, and while compressing the pressing means 30, the four protrusions (not shown) formed at corresponding locations on the second holding member 10Bb are engaged with the two recesses 17 formed at each of the first end 10Baa and second end 10Bab of the first holding member 10Ba, thereby forming the holding member 10B.

[0080] Next, prepare the cover 10A. Then, insert the retaining member 10B into the housing portion 22 of the cover 10A. Next, inject adhesive into the terminal adhesive injection port 16 of the retaining member 10B to fill the gap between the terminal mounting surface 111 and the first terminal 91 and the second terminal 92. Also, inject adhesive into the inclined surface 21 of the elliptical side of the cover 10A, which is the case adhesive injection port, to bond the cover 10A and the retaining member 10B. As the adhesive, for example, an adhesive containing a thermosetting resin can be used. In this way, an insulating case 10 with the inside of the cover 10A sealed is formed. Through the above steps, the protective element 100 of this reference example can be obtained.

[0081] In the protective element 100 of this reference example, if an overcurrent exceeding the rated current flows through the fuse element 50 (multiple fusible conductive sheets 50a to 50f), the fuse element 50 is thermally melted to interrupt the current path. In addition, current is passed through the heating element 80 to melt the locking member 70 that suppresses the movement of the shielding member 20, and the pressing means 30 moves the shielding member 20, thereby physically cutting the fuse element 50 and interrupting the current path.

[0082] In the protective element 100 of this reference example, the movement of the shielding member 20, which is subjected to a pressing force by the pressing means 30, is suppressed by the locking member 70. Therefore, except when the current path is interrupted, no cutting pressing force is applied to the fuse element 50 (multiple fusible conductor sheets 50a to 50f) by the pressing means 30 and the shielding member 20. As a result, deterioration of the fuse element 50 over time is suppressed, and disconnection caused by the pressing force being applied when the fuse element 50 heats up when interruption of the current path is not necessary can be prevented.

[0083] In the protective element 100 of this reference example, the fuse element laminate 40 includes a plurality of fusible conductor sheets 50a to 50f arranged in parallel in the thickness direction, and each of the fusible conductor sheets 50a to 50f is in close proximity to or in contact with (tightly attached to) the first insulating members 60Aa to 60Af and the second insulating member 60B arranged between them, thereby providing insulation. As a result, the current value flowing through each of the fusible conductor sheets 50a to 50f becomes small, and the space surrounding the fusible conductor sheets 50a to 50f becomes extremely narrow, making it easier to reduce the scale of the arc discharge generated by melting. In other words, when the melting space is narrow, there is less gas in that space, and the amount of "plasma generated by the ionization of gas in the space," which is the path through which the current flows during the arc discharge, also decreases, making it easier to extinguish the arc discharge early. Therefore, with the protective element 100 of this reference example, it is possible to make the size of the insulating case 10 smaller and lighter.

[0084] In the protective element 100 of this reference example, a first insulating member 60Aa is placed between the soluble conductive sheet 50a, which is located at the bottom of the soluble conductive sheets 50a to 50f, and the first retaining member 10Ba of the insulating case 10. Furthermore, a second insulating member 60B is placed between the soluble conductive sheet 50f, which is located at the top of the soluble conductive sheets 50a to 50f, and the second retaining member 10Bb of the insulating case 10. As a result, the soluble conductive sheets 50a and 50f do not come into direct contact with the first retaining member 10Ba and the second retaining member 10Bb. Therefore, carbides that form conductive paths are less likely to form on the inner surface of these insulating cases 10 due to arc discharge, and leakage current is less likely to occur even if the size of the insulating case 10 is reduced.

[0085] In the protective element 100 of this reference example, if the first insulating members 60Aa to 60Af and the second insulating member 60B are separated at a position facing the fused portion 53 between the first end 51 and the second end 52 of the fusible conductive sheets 50a to 50f, the continuous adhesion of molten material to the surfaces of the first insulating members 60Aa to 60Af and the second insulating member 60B can be suppressed when the fusible conductive sheets 50a to 50f are fused at the fused portion 53. Therefore, the arc discharge generated by the fusion of the fusible conductive sheets 50a to 50f can be extinguished early.

[0086] In the protective element 100 of this reference example, if at least one of the first insulating members 60Aa to 60Af, the second insulating member 60B, the shielding member 20, the cover 10A of the insulating case 10, and the retaining member 10B is made of a material with a tracking resistance index CTI of 500V or higher, then carbides that form conductive paths are less likely to form on the surfaces of these components due to arc discharge, and thus leakage current is less likely to occur even if the size of the insulating case 10 is reduced.

[0087] In the protective element 100 of this reference example, if at least one of the first insulating members 60Aa to 60Af, the second insulating member 60B, the shielding member 20, the cover 10A of the insulating case 10, and the retaining member 10B is made of a polyamide resin or a fluororesin, then because polyamide resins and fluororesins have excellent insulating properties and tracking resistance, it becomes easier to achieve both miniaturization and weight reduction.

[0088] In the protective element 100 of this reference example, each of the soluble conductive sheets 50a to 50f is a laminate containing a low-melting-point metal layer and a high-melting-point metal layer. If the low-melting-point metal layer contains Sn and the high-melting-point metal layer contains Ag or Cu, the high-melting-point metal is dissolved by Sn when the low-melting-point metal layer melts, thus lowering the fuse temperature of the soluble conductive sheets 50a to 50f. Furthermore, since Ag and Cu have higher physical strength than Sn, the physical strength of the soluble conductive sheets 50a to 50f, which have a high-melting-point metal layer laminated on top of a low-melting-point metal layer, is higher than the physical strength of the low-melting-point metal layer alone. Moreover, since Ag and Cu have lower electrical resistivity than Sn, the electrical resistance of the soluble conductive sheets 50a to 50f, which have a high-melting-point metal layer laminated on top of a low-melting-point metal layer, is lower than the electrical resistance of the low-melting-point metal layer alone. In other words, it becomes a fuse element that can handle higher currents.

[0089] In the protective element 100 of this reference example, if each of the soluble conductive sheets 50a to 50f is a laminate 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 positioned between the high-melting-point metal layers, the strength of the soluble conductive sheets 50a to 50f is increased because there are high-melting-point metal layers on the outside. In particular, when the first end 51 of the soluble conductive sheets 50a to 50f is connected to the first terminal 91 and the second end 52 to the second terminal 92 by soldering, deformation of the soluble conductive sheets 50a to 50f due to heating during soldering becomes less likely.

[0090] In the protective element 100 of this reference example, if each of the soluble conductive sheets 50a to 50f is a single layer containing silver or copper, the electrical resistivity tends to be lower compared to the case where it is a laminate of a high-melting-point metal layer and a low-melting-point metal layer. For this reason, soluble conductive sheets 50a to 50f made of single layers containing silver or copper can be made thinner even if they have the same electrical resistance over the same area as soluble conductive sheets 50a to 50f made of a laminate of a high-melting-point metal layer and a low-melting-point metal layer. When the soluble conductive sheets 50a to 50f are thin, the amount of molten material scattered when the soluble conductive sheets 50a to 50f are cut also decreases in proportion to the thickness, and the insulation resistance after cutting increases.

[0091] In the protective element 100 of this reference example, each of the fusible conductive sheets 50a to 50f has a through hole 54 in the fusible portion 53, and the fusible portion has such that the cross-sectional area of ​​the fusible portion 53 in the direction of current flow is smaller than the cross-sectional area of ​​the first end 51 and the second end 52 in the direction of current flow, so that the part that melts when a current exceeding the rating flows through the current path is stable. In this reference example, the protective element 100 has a through hole 54 in the fusible portion 53, but there are no particular restrictions on the method of reducing the cross-sectional area of ​​the fusible portion 53. For example, the cross-sectional area of ​​the fusible portion 53 may be reduced by cutting out both ends of the fusible portion 53 in a concave shape or by partially reducing its thickness.

[0092] (modified version) Figure 10 is a schematic diagram of a modified example of the first reference example, where (a) is a perspective view of a retaining member 10BB, which is a modified example of the retaining member 10B, and (b) is a perspective view of a configuration in which the first insulating member 61A and the second insulating member 61B, which are modified examples of the first insulating member 60A and the second insulating member 60B, have an opening through which the convex portion 20a of the shielding member 20 can move (pass). Figure 11(a) shows a schematic perspective view of the second insulating member, and (b) shows a schematic perspective view of the first insulating member. Note that the six first insulating members have the same shape, so the first insulating member shown in Figure 11(b) shows their common configuration. In this modified example, the fuse element laminate has the same configuration as shown in Figure 4, except for the first insulating member. Therefore, in the following explanation, members common to those shown in Figure 4 will be denoted by the same reference numerals.

[0093] Each of the first insulating members 61Aa to 61Af shown in Figures 10 and 11 has a first opening 64A, and the second insulating member 61B has a second opening 65A. Furthermore, the lengths in the Y direction of the first opening 64A and the second opening 65A are greater than the lengths in the Y direction of the soluble conductive sheets 50a to 50f and the convex portion 20a of the shielding member 20. As a result, after the soluble conductive sheets 50a to 50f are blocked, the convex portion 20a is inserted into the first opening 64A and the second opening 65A, and the cut portion of the soluble conductive sheets 50a to 50f is reliably shielded. Each of the first insulating members 61Aa to 61Af and the second insulating member 61B have ventilation holes 67A on both ends in the Y direction to efficiently release the pressure rise associated with the arc discharge that occurs when the fuse element is interrupted into the pressing means housing space of the insulating case. In the illustrated example, each of the first insulating members 61Aa to 61Af and the second insulating member 61B have five ventilation holes 67A on both ends in the Y direction, on the left and right sides of the first opening 64A or the second opening 65A, but there is no limit to the number. The rising pressure generated by the arc discharge is efficiently released through the ventilation hole 67A and through the gaps (not shown) at the four corners provided between the pressing means support portion 20b and the second holding member 10BBb into the space housing the pressing means 30 in the insulating case 10. As a result, the shielding operation of the shielding member 20 is performed smoothly, and the destruction of the first insulating members 61Aa~61Af and the second insulating member 61B is prevented. The first opening 64A and the second opening 65A are located opposite the cut section 53, which is positioned between the first end 51 and the second end 52 of the soluble conductive sheets 50a to 50f.

[0094] The materials for the first insulating members 61Aa to 61Af and the second insulating member 61B are preferably the same as those for the first insulating members 60Aa to 60Af and the second insulating member 60B, and similar types of materials can be used.

[0095] The retaining members 10BB shown in Figures 10(a) and 10(b) (a second retaining member 10BBb positioned on the upper side in the Z direction and a first retaining member 10BBa positioned on the lower side in the Z direction) have shapes corresponding to modified examples of the first insulating member and the second insulating member.

[0096] (Protective element (second reference example)) Figures 12 to 15 are schematic diagrams showing the protective element according to the second reference example. The main difference between the protective element according to the second reference example and the protective element according to the first reference example is that, as a mechanism for interrupting the current path, the protective element according to the second reference example does not have an active interruption mechanism using a heating element, but only an overcurrent interruption mechanism that interrupts the current path by melting the soluble conductor sheet when an overcurrent exceeding the rated current flows through the soluble conductor sheet. Specifically, the main difference between the protective element according to the second reference example and the protective element according to the first reference example is that it does not have a heating element or a power supply member. In the following drawings, components that are similar or substantially similar to the protective element in the first reference example are given the same reference numerals and their descriptions are omitted. Figure 12(a) is a schematic perspective view corresponding to Figure 2, with a portion removed to show the inside of the protective element, and (b) is a perspective view of the shielding member. Figure 13 is a cross-sectional view of the protective element according to the second reference example, corresponding to Figure 5(a). Figure 14 is a cross-sectional view corresponding to Figure 6, showing the protective element in a state where the shielding member has cut the fuse element and lowered completely. Figure 15 is a schematic perspective view showing the fuse element laminate, the first terminal and the second terminal installed on the first holding member.

[0097] The protective element 200 shown in Figures 12 to 15 comprises an insulating case 11, a fuse element laminate 140, a first insulating member 160A, a shielding member 120, a pressing means 30, and a locking member 170. In this reference example of the protective element 200, the current direction refers to the direction in which electricity flows during use (X direction), and the cross-sectional area in the current direction refers to the area of ​​the plane (YZ plane) perpendicular to the current direction.

[0098] (Insulating case) The insulating case 11 is approximately cylindrical in shape (the cross-section of the YZ plane is oval at any position in the X direction). The insulating case 11 consists of a cover 110A and a retaining member 110B. Since the protective element 200 does not have a heating element or a power supply member, the cover 110A and the retaining member 110B differ from the cover 10A and the retaining member 10B in that they do not have parts for a heating element or a power supply member. The retaining member 110B consists of a first retaining member 110Ba positioned on the lower side in the Z direction and a second retaining member 110Bb positioned on the upper side in the Z direction. The cover 110A and the retaining member 110B are roughly cylindrical in shape to be compact and withstand the rise in internal pressure due to arc discharge, thereby reducing the amount of material used. However, the outer shape is not limited to a roughly cylindrical shape; it can take any shape, such as a rectangular parallelepiped, as long as no damage occurs due to arc discharge, depending on the rated voltage, rated current, and breaking capacity of the protective element.

[0099] An internal pressure buffer space 15 (see Figure 14) is formed inside the holding member 110B. The internal pressure buffer space 15 has the effect of suppressing the rapid rise in internal pressure of the protective element 200 caused by the gas generated by the arc discharge that occurs when the fuse element laminate 140 melts.

[0100] The same materials as those used for cover 10A and retaining member 10B can be used for cover 110A and retaining member 110B.

[0101] (Fuse element stack) The fuse element laminate 140 comprises a plurality of soluble conductive sheets 50 (sometimes referred to collectively as the fuse element 50) arranged in parallel in the thickness direction, and a plurality of first insulating members 160A (160Aa to 160Ag) which are arranged in close proximity to or in contact with the outside of the soluble conductive sheets 50 located between each of the plurality of soluble conductive sheets 50, and the bottommost and topmost of the plurality of soluble conductive sheets 50, and which have first openings formed therein. The fuse element laminate 140 consists of the fuse element and the first insulating members. The multiple soluble conductive sheets 50 have the same configuration as those shown in Figure 4, and the description of their features described above is omitted. Furthermore, the multiple first insulating members 160A (160Aa to 160Ag) all have the same configuration, and are identical to the first insulating member 61A shown in Figure 10(b), and the description of their features described above is omitted.

[0102] The protective element 200 shown in Figures 12 to 15 differs from the protective element 100 in that it has a first insulating member in the same location as the second insulating member 60B. In the protective element 200 as well, instead of the first insulating member placed at the top, an insulating member with a different configuration from the first insulating member may be provided. In this case, the protective element 100 differs from the first insulating member 60A in that the second insulating member 60B has a location for arranging the heating element 80. However, it is also possible to substitute it with a configuration similar to the first insulating member 60A, in which case there is no difference in configuration between the second insulating member 60B and the first insulating member 60A, and in this case both the protective element 100 and the fuse element laminate 40 consist of a fuse element and the first insulating member.

[0103] The fuse element laminate 140 has six soluble conductive sheets 50a, 50b, 50c, 50d, 50e, and 50f arranged in parallel in the thickness direction (Z direction). Between each of the soluble conductive sheets 50a to 50f, first insulating members 160Ab, 160Ac, 160Ad, 160Ae, and 160Af are arranged. The first insulating members 160Ab to 160Af are arranged in close proximity to or in contact with each of the soluble conductive sheets 50a to 50f. In the close proximity state, the distance between the first insulating members 160Ab to 160Af and the soluble conductive sheets 50a to 50f is preferably 0.5 mm or less, and more preferably 0.2 mm or less. Furthermore, a first insulating member 160Aa is placed on the outside of the soluble conductor sheet 50a, which is located at the bottom of the soluble conductor sheets 50a to 50f. In addition, a first insulating member 160Ag is placed on the outside of the soluble conductor sheet 50f, which is located at the top of the soluble conductor sheets 50a to 50f. The width (length in the Y direction) of the soluble conductor sheets 50a to 50f is narrower than the width of the first insulating members 160Aa to 160Ag. The fuse element laminate 140 is an example of having six soluble conductive sheets, but it is not limited to six; any number of sheets is acceptable. Furthermore, in each of the soluble conductive sheets 50a to 50f, the cut portion 53, which is configured to be easily cut, is easily cut by the convex portion 120a of the shielding member 120.

[0104] The thickness of the soluble conductive sheets 50a to 50f is defined as the thickness at which they melt due to overcurrent. The specific thickness depends on the material and number of soluble conductive sheets 50a to 50f, as well as the pressing force (stress) of the pressing means 30. For example, if the soluble conductive sheets 50a to 50f are copper foil, the thickness can be in the range of 0.01 mm to 0.1 mm as a guideline. Furthermore, if the soluble conductive sheets 50a to 50f are foils in which an alloy mainly composed of Sn is plated with Ag, the thickness can be in the range of 0.1 mm to 1.0 mm as a guideline.

[0105] Each of the first insulating members 160Aa to 160Ag has a first opening 64A in the center in the X direction through which the convex portion 120a of the shielding member 120 can move (pass). The first insulating members 160Aa to 160Ag have ventilation holes 67A to efficiently release the pressure rise associated with the arc discharge that occurs when the fuse element is interrupted into the pressing means housing space of the insulating case. In the illustrated example, the first insulating members 160Aa to 160Ag each have five ventilation holes 67A on both ends in the Y direction, on either side of the first opening 64A, but there is no limit to the number. The rising pressure generated by the arc discharge is efficiently released through the ventilation hole 67A and through the gaps (not shown) at the four corners provided between the pressing means support portion 120b and the second holding member 110Bb into the space housing the pressing means 30 in the insulating case 11. As a result, the shielding operation of the shielding member 120 is performed smoothly, and the destruction of the first insulating members 160Aa to 160Ag is prevented. The first opening 64A is located opposite the cut portion 53, which is positioned between the first end 51 and the second end 52 of the soluble conductive sheets 50a to 50f.

[0106] (Shielding material) The shielding member 120 has a convex portion 120a facing the fuse element stack 140 side and a pressing means support portion 120b having a recess 120ba that accommodates and supports the lower part of the pressing means 30. The tip of the convex portion 120a has a clamping groove 120aA for clamping the locking member 170. The shielding member 120 has three clamping grooves 120aA, but there is no limit to the number. The shielding member 120 is subjected to downward pressure from the pressing means 30, and its downward movement is restricted by the locking member 170. Since the protruding portion 170b of the locking member 170 is in contact with the soluble conductive sheet 50f, if an overcurrent exceeding the rated current flows through the soluble conductive sheet, the locking member 170 will heat up and soften at a temperature above its softening temperature. Furthermore, if a large overcurrent flows and the soluble conductive sheet 50f melts instantly, the resulting arc discharge will also flow through the locking member 170, causing it to soften at a temperature above its softening temperature. The softened locking member 170 becomes more susceptible to physical cutting by the convex portion 120a of the shielding member 120, which is pressed by the pressing force of the pressing means 30. When the locking member 170 is cut and the downward movement restriction by the locking member 170 is released, the shielding member 120 moves downward and physically cuts the soluble conductive sheets 50a to 50f. In the shielding member 120, the tip 120aa of the convex portion 120a is pointed, making it easy to cut the soluble conductive sheets 50a to 50f. Figure 14 shows a cross-sectional view of the protective element in the state where the shielding member 120 has moved through the first opening 64A of the fuse element laminate 140, and the convex portion 120a has cut through the soluble conductive sheets 50a, 50b, 50c, 50d, 50e, and 50f, and the shielding member 120 has been lowered to its lowest position.

[0107] As the shielding member 120 moves down through the first opening 64A of the fuse element stack 140, the convex portion 120a of the shielding member 120 sequentially cuts the fusible conductor sheets 50f, 50e, 50d, 50c, 50b, and 50a. The cut surfaces are shielded and insulated from each other by the convex portion 120a, and the current path through each fusible conductor sheet is physically and reliably blocked. As a result, the arc discharge is quickly extinguished. Furthermore, when the shielding member 120 moves down completely through the first opening 64A of the fuse element stack 140, the pressing means support portion 120b of the shielding member 120 presses the fuse element stack 140 from the first insulating member 160Ag, causing the fusible conductor sheet and the first insulating members 160Aa to 160Ag to be in close contact. As a result, there is no longer any space between them where arc discharge can continue, and the arc discharge is reliably extinguished.

[0108] The thickness (length in the X direction) of the convex portion 120a is smaller than the width in the X direction of the first opening 64A of the first insulating members 160Aa to 160Ag. This configuration allows the convex portion 120a to move downward in the Z direction relative to the first opening 64A. For example, if the soluble conductive sheets 50a to 50f are copper foil, the difference between the thickness of the convex portion 120a and the width of the first opening 64A in the X direction can be, for example, 0.05 to 1.0 mm, and preferably 0.2 to 0.4 mm. If the difference is 0.05 mm or more, even if the end of the soluble conductive sheet 50a to 50f with a minimum cut thickness of 0.01 mm gets caught in the gap between the first insulating member 160Aa to 160Ag and the convex portion 120a, the movement of the convex portion 120a becomes smoother, and the arc discharge is extinguished more quickly and reliably. This is because if the above difference is 0.05 mm or more, the convex portion 120a is less likely to get caught. Also, if the above difference is 1.0 mm or less, the first opening 64A functions as a guide for moving the convex portion 120a. Therefore, displacement of the convex portion 120a, which moves when the soluble conductive sheets 50a to 50f are cut, is prevented, and the arc discharge is extinguished more quickly and reliably. If the soluble conductive sheets 50a to 50f are foils in which an alloy mainly composed of Sn is plated with Ag, the difference between the thickness of the convex portion 120a and the width of the first opening 64A in the X direction can be, for example, 0.2 to 2.5 mm, and preferably 0.22 to 2.2 mm.

[0109] The width (length in the Y direction) of the convex portion 120a is wider than the width of the soluble conductive sheets 50a to 50f of the fuse element laminate 140. This configuration makes it possible for the convex portion 120a to cut each of the soluble conductive sheets 50a to 50f.

[0110] The length L in the Z direction of the convex portion 120a is such that, when it is fully extended downwards in the Z direction, the tip 120aa of the convex portion 120a can reach below the first insulating member 160Aa, which is located at the lowest point in the Z direction among the first insulating members 160Aa to 160Ag. When the convex portion 120a is lowered below the first insulating member 160Aa, which is located at the lowest point, it is inserted into the insertion hole 114 formed on the inner bottom surface of the holding member 110Ba. This configuration allows the convex portion 120a to cut through each of the soluble conductive sheets 50a to 50f.

[0111] (Pressing means) The pressing means 30 is housed in the recess 120ba of the shielding member 120 while pressing the shielding member 120 downward in the Z direction. The pressing means 30 can be the same as that provided in the protective element 100.

[0112] (locking member) The locking member 170 may be constructed in the same way as the locking member 70, including its shape and material. The protective element 200 is provided with three locking members 170, but is not limited to three. The locking member 170 is held in place by being inserted into the clamping groove 120aA provided at the tip 120aa of the convex portion 120a of the shielding member 120.

[0113] The locking member 170 has a T-shape and includes a lateral extension (support portion) 170a consisting of a first arm portion 170aa and a second arm portion 170ab, and a longitudinal extension (projection portion) 170b extending downward from the central part of the lateral extension portion 170a. In the protective element 200, the lateral extension portion 170a is supported by the shielding member side surface 160AgS of the first insulating member 160Ag, with the first arm portion 170aa and the second arm portion 170ab each sandwiching the first opening 64A, and the vertical extension portion 170b is supported at its lower end by the shielding member side surface 50fS of the soluble conductive sheet 50f. In the illustrated example, the shielding member side surface 160AgS of the first insulating member 160Ag does not have a groove on which the locking member 170 is placed, but it may have a groove on which the locking member 170 is placed. When the longitudinal extension 170b is supported on the shielding member side surface 50fS of the soluble conductive sheet 50f, when an overcurrent exceeding the rated current flows through the soluble conductive sheet 50f, the locking member 170 in contact with the soluble conductive sheet 50f heats up and softens at a temperature above the softening temperature. In the protective element 200, both the lateral extension 170a and the longitudinal extension 170b are supported, but either one may be supported. However, it is preferable that the longitudinal extension 170b is supported in contact with the shielding member side surface 50fS of the soluble conductive sheet 50f so that it softens when an overcurrent exceeding the rated current flows through the soluble conductive sheet 50f. If the longitudinal extension 170b is not in contact with the shielding member side surface 50fS of the soluble conductive sheet 50f, it is preferable that it is in close proximity to the shielding member side surface 50fS.

[0114] The three locking members 170 are all the same shape, but some may have different shapes.

[0115] When the locking member 170 reaches a temperature above its softening temperature, it becomes soft enough to deform under external force. The softened locking member 170 becomes more easily physically cut by the convex portion 120a of the shielding member 120, which is pressed by the pressing force of the pressing means 30. When the locking member 170 is cut, the convex portion 120a of the shielding member 120 is inserted downward in the Z direction through the first opening 64A. As the convex portion 120a is inserted downward in the Z direction through the first opening 64A, it cuts through the fusible conductive sheet as it advances and reaches its lowest position. In this way, the convex portion 120a shields the fusible conductive sheets 50a to 50f from the first terminal 91 side and the second terminal 92 side with its cut portion 53. This allows the arc discharge generated when the fusible conductive sheets 50a to 50f are cut to be extinguished quickly and reliably.

[0116] In the locking member 170, the longitudinally extended portion 170b is in contact with the soluble conductive sheet 50f. Therefore, when an overcurrent exceeding the rated current flows through the soluble conductive sheet, the locking member 170 in contact with the soluble conductive sheet 50f heats up and softens at a temperature above its softening temperature. Furthermore, if a large overcurrent flows and the soluble conductive sheet 50f melts instantaneously, the resulting arc discharge will also flow to the locking member 170, causing the locking member 170 to soften at a temperature above its softening temperature. The softened locking member 170 becomes more easily physically cut by the convex portion 120a of the shielding member 120, which is pressed by the pressing force of the pressing means 30. When the locking member 170 is cut, the convex portion 120a of the shielding member 120 is inserted downward in the Z direction through the first opening 64A. In this case, the soluble conductive sheet is thermally melted due to an overcurrent exceeding the rated current, and the convex portion 120a is inserted downward in the Z direction through the first opening 64A. At this time, the convex portion 120a shields the soluble conductive sheets 50a to 50f from the first terminal 91 side and the second terminal 92 side at its melted portion. This allows the arc discharge generated when the soluble conductive sheets 50a to 50f are cut to be extinguished quickly and reliably. Even if the soluble conductive sheet has not yet been thermally cut, as the convex portion 120a is inserted downward in the Z direction through the first opening 64A, the convex portion 120a cuts through the soluble conductive sheet as it advances and reaches the lowest position. In this way, the convex portion 120a shields the soluble conductive sheets 50a to 50f from the first terminal 91 side and the second terminal 92 side at its cut portion. This allows the arc discharge that occurs when the soluble conductive sheets 50a to 50f are cut off to be extinguished quickly and reliably.

[0117] The protective element 200 according to the second reference example has many components that are the same as or similar to the protective element 100 according to the first reference example, except that it does not have a heating element and a power supply member; therefore, a description of its manufacturing method will be omitted.

[0118] In the protective element 200 of this reference example, if an overcurrent exceeding the rated current flows through the fuse element 50 (multiple fusible conductive sheets 50a to 50f), the fuse element 50 is thermally melted, interrupting the current path.

[0119] In the protective element 200 of this reference example, the movement of the shielding member 120, which is subjected to a pressing force by the pressing means 30, is suppressed by the locking member 170. Therefore, except when the current path is interrupted, no cutting pressing force is applied to the fuse element 50 (multiple fusible conductor sheets 50a to 50f) by the pressing means 30 and the shielding member 120. As a result, deterioration of the fuse element 50 over time is suppressed, and disconnection caused by the pressing force being applied when the fuse element 50 heats up when interruption of the current path is not necessary can be prevented.

[0120] In the protective element 200 of this reference example, the fuse element laminate 140 includes a plurality of soluble conductor sheets 50a to 50f arranged in parallel in the thickness direction, and each of the soluble conductor sheets 50a to 50f is in close proximity to or in contact with (tightly attached to) the first insulating members 160Ab to 160Af and the first insulating members 160Aa to 160Ag arranged outside the soluble conductor sheets 50a and 50f, thereby providing insulation. As a result, the current value flowing through each of the soluble conductor sheets 50a to 50f becomes small, and the space surrounding the soluble conductor sheets 50a to 50f becomes extremely narrow, making it easier to reduce the scale of the arc discharge generated by melting. Therefore, with the protective element 200 of this reference example, it is possible to make the size of the insulating case 11 smaller and lighter.

[0121] In the protective element 200 of this reference example, if a first insulating member 160Aa is placed between the soluble conductive sheet 50a, which is located at the bottom of the soluble conductive sheets 50a to 50f, and the first retaining member 110Ba of the insulating case 11, and if an insulating member 160Ag is placed between the soluble conductive sheet 50f, which is located at the top of the soluble conductive sheets 50a to 50f, and the second retaining member 110Bb of the insulating case 11, then the soluble conductive sheets 50a and 50f do not come into direct contact with the first retaining member 110Ba and the second retaining member 110Bb, respectively. As a result, carbides that form conductive paths are less likely to form on the inner surface of these insulating cases 11 due to arc discharge, and leakage current is less likely to occur even if the size of the insulating case 11 is reduced.

[0122] In the protective element 200 of this reference example, if the first insulating members 160Aa to 160Ag have an opening at a position facing the fused portion 53 between the first end 51 and the second end 52 of the fusible conductive sheets 50a to 50f, it is possible to suppress the continuous adhesion of molten material to the surface of the first insulating members 160Aa to 160Ag when the fusible conductive sheets 50a to 50f are fused at the fused portion 53. Therefore, the arc discharge generated by the fusion of the fusible conductive sheets 50a to 50f can be extinguished at an early stage.

[0123] In the protective element 200 of this reference example, if at least one of the first insulating member 160Aa to 160Ag, the shielding member 120, the cover 110A of the insulating case 11, and the retaining member 110B is made of a material with a tracking resistance index CTI of 500V or higher, then carbides that form conductive paths are less likely to form on the surfaces of these components due to arc discharge, and leakage current is less likely to occur even if the size of the insulating case 11 is reduced.

[0124] In the protective element 200 of this reference example, if at least one of the first insulating members 160Aa to 160Ag, the shielding member 120, the cover 110A of the insulating case 11, and the retaining member 110B is made of a polyamide resin or a fluororesin, then because polyamide resins and fluororesins have excellent insulating properties and tracking resistance, it becomes easier to achieve both miniaturization and weight reduction.

[0125] In the protective element 200 of this reference example, each of the soluble conductive sheets 50a to 50f is a laminate containing a low-melting-point metal layer and a high-melting-point metal layer. If the low-melting-point metal layer contains Sn and the high-melting-point metal layer contains Ag or Cu, the high-melting-point metal is dissolved by Sn when the low-melting-point metal layer melts, thus lowering the fuse temperature of the soluble conductive sheets 50a to 50f. Furthermore, since Ag and Cu have higher physical strength than Sn, the physical strength of the soluble conductive sheets 50a to 50f, which have a high-melting-point metal layer laminated on top of a low-melting-point metal layer, is higher than the physical strength of the low-melting-point metal layer alone. Moreover, since Ag and Cu have lower electrical resistivity than Sn, the electrical resistance of the soluble conductive sheets 50a to 50f, which have a high-melting-point metal layer laminated on top of a low-melting-point metal layer, is lower than the electrical resistance of the low-melting-point metal layer alone. In other words, it becomes a fuse element that can handle higher currents.

[0126] In the protective element 200 of this reference example, if each of the soluble conductive sheets 50a to 50f is a laminate 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 positioned between the high-melting-point metal layers, the strength of the soluble conductive sheets 50a to 50f is increased because there are high-melting-point metal layers on the outside. In particular, when the first end 51 of the soluble conductive sheets 50a to 50f is connected to the first terminal 91 and the second end 52 to the second terminal 92 by soldering, deformation of the soluble conductive sheets 50a to 50f due to heating during soldering becomes less likely.

[0127] In the protective element 200 of this reference example, if each of the soluble conductive sheets 50a to 50f is a single layer containing silver or copper, the electrical resistivity tends to be lower compared to the case where it is a laminate of a high-melting-point metal layer and a low-melting-point metal layer. For this reason, soluble conductive sheets 50a to 50f made of single layers containing silver or copper can be made thinner even if they have the same electrical resistance over the same area as soluble conductive sheets 50a to 50f made of a laminate of a high-melting-point metal layer and a low-melting-point metal layer. When the soluble conductive sheets 50a to 50f are thin, the amount of molten material scattered when the soluble conductive sheets 50a to 50f are cut also decreases in proportion to the thickness, and the insulation resistance after cutting increases.

[0128] In the protective element 200 of this reference example, each of the fusible conductive sheets 50a to 50f has a through hole 54 in the fusible portion 53, and the fusible portion has such that the cross-sectional area of ​​the fusible portion 53 in the direction of current flow is smaller than the cross-sectional area of ​​the first end 51 and the second end 52 in the direction of current flow, so that the part that melts when a current exceeding the rating flows through the current path is stable. In this reference example, the protective element 200 has a through hole 54 in the fusible portion 53, but there are no particular restrictions on the method of reducing the cross-sectional area of ​​the fusible portion 53. For example, the cross-sectional area of ​​the fusible portion 53 may be reduced by cutting out both ends of the fusible portion 53 in a concave shape or by partially reducing its thickness.

[0129] (Protective element (embodiment)) A protective element 250 according to an embodiment of the present invention will be described with reference to Figures 16 to 19. The protective element 250 of this embodiment differs from the first and second reference examples described above mainly in its configuration, including the arrangement of the locking member 270 and the heating element 80. In the figures of this embodiment, components that are the same as or substantially the same as those in the first and second reference examples may be given the same reference numerals or names, and their descriptions may be omitted.

[0130] Figure 16 is a cross-sectional view of the protective element 250 of this embodiment, specifically a cross-sectional view showing the protective element 250 as a cross-section (XZ section) perpendicular to the width direction (Y direction). The protective element 250 includes an insulating case 260, a fuse element (fusible conductive sheet) 50, a first terminal 91, a second terminal 92, an insulating member 60, a shielding member 220, a pressing means 230, a heating element 80, a locking member 270, and a power supply member 90.

[0131] (Insulating case) The insulating case 260 has at least two (three in this embodiment) retaining members 260Ba, 260Bb, and 260Bc arranged in a stack in the vertical direction (Z direction), and a cylindrical cover 260A that houses these retaining members 260Ba, 260Bb, and 260Bc. The cover 260A is fitted onto the outside of the plurality of retaining members 260Ba, 260Bb, and 260Bc.

[0132] At least two retaining members 260Ba and 260Bb are positioned on both sides of the fuse element 50 in the vertical direction. Specifically, of the three retaining members 260Ba, 260Bb, and 260Bc, the first retaining member 260Ba, which is positioned at the bottom, is positioned below the fuse element 50. Also, of the three retaining members 260Ba, 260Bb, and 260Bc, the second retaining member 260Bb is positioned above the fuse element 50. Of the three retaining members 260Ba, 260Bb, and 260Bc, the third retaining member 260Bc is positioned at the top.

[0133] The first retaining member 260Ba has an inner bottom surface 13 positioned on the upper surface of its bottom wall and facing upward. That is, the insulating case 260 has an inner bottom surface 13. The inner bottom surface 13 has a groove 14 that extends along the opening or separation portion of the insulating member 60. The groove 14 extends along the width direction (Y direction) and opens upward.

[0134] The second retaining member 260Bb has a heat-generating element housing recess 261. The heat-generating element housing recess 261 is located on the inner surface of the side wall of the second retaining member 260Bb, facing inward (towards the center) in the direction of current flow (X direction). Specifically, the heat-generating element housing recess 261 is located at the upper end of the inner surface of the side wall of the second retaining member 260Bb. The heat-generating element housing recess 261 is recessed outward in the direction of current flow from the inner surface of the side wall of the second retaining member 260Bb, relative to the portion adjacent to the lower side of the heat-generating element housing recess 261. The arrangement of the heating element housing recess 261 is not limited to the inner surface facing inward (towards the center) in the direction of current flow (X direction), but may also be arranged on the inner surface of the side wall of the second holding member 260Bb that faces inward (towards the center) in the width direction (Y direction) perpendicular to the direction of current flow (X direction).

[0135] The heating element housing recesses 261 are provided in pairs on the inner surface of the side wall of the second retaining member 260Bb, facing each other in the direction of current flow. That is, the pair of heating element housing recesses 261 are located on the inner surface of the side wall of the second retaining member 260Bb, at the end on the first terminal 91 side (+X side) and the end on the second terminal 92 side (-X side) in the direction of current flow. The heating element housing recesses 261 are not limited to a pair; one may be placed on each side.

[0136] Figure 18 is a schematic cross-sectional view showing a part of the protective element 250 of Figure 16, specifically representing a cross-section perpendicular to the width direction (XZ cross-section). As shown in Figure 18, the second retaining member 260Bb (i.e., the insulating case 260) has a second stage portion 263. The second stage portion 263 is located at the lower end of the heating element housing recess 261 and faces upward. A pair of second stage portions 263 are provided in each of the pair of heating element housing recesses 261 (i.e., a pair). If one heating element housing recess 261 is located on one side, a second stage portion 263 is provided in the heating element housing recess 261.

[0137] As shown in Figure 16, the third retaining member 260Bc has a pressing means housing recess 262. The pressing means housing recess 262 is located on the lower surface of the top wall of the third retaining member 260Bc and is recessed upward. Figure 16 shows the case where the pressing means 230 is a conical spring and its upper diameter is smaller than its lower diameter. However, if the upper diameter of the conical spring is larger than the lower diameter, or if it is a cylindrical spring, the recess 262 for housing the pressing means may not be necessary.

[0138] The insulating case 260 houses the fuse element 50, a portion of the first terminal 91, a portion of the second terminal 92, an insulating member 60, a shielding member 220, a pressing means 230, a heating element 80, a locking member 270, and a portion of the power supply member 90.

[0139] (Fuse element) Multiple fuse elements 50 are provided arranged in a vertical direction (thickness direction). In this embodiment, four fuse elements 50 are arranged in parallel in the vertical direction. Insulating members 60 are provided between adjacent fuse elements 50 in the vertical direction, and on the upper side (outside) of the uppermost fuse element 50 (50f).

[0140] Furthermore, the inner bottom surface 13 of the first retaining member 260Ba is positioned in close proximity to or in contact with the lower (outside) side of the fuse element 50 (50a) located at the very bottom. In other words, the inner bottom surface 13 is positioned in close proximity to or in contact with the side of the fuse element 50 opposite to the shielding member 220 (i.e., the bottom side). More specifically, the inner bottom surface 13 is positioned in close proximity to or in contact with the outside of the outermost layer (fuse element 50a) of the multiple fuse elements 50, opposite to the shielding member 220.

[0141] The fuse element 50 is plate-shaped and extends in the direction of current flow. The pair of surfaces (front and back) of the fuse element 50 face in the vertical direction. The vertical direction is perpendicular to the surface of the fuse element 50, so it can also be called the vertical direction. Multiple fuse elements 50 are stacked in parallel in the vertical direction.

[0142] The fuse element 50 has a first end 51 and a second end 52 that are opposite to each other. In other words, the fuse element 50 has a first end 51 and a second end 52 that are located at both ends in the direction of current flow.

[0143] (1st terminal, 2nd terminal) One end of the first terminal 91 is connected to the first end 51, and the other end is exposed to the outside from the insulating case 260. Specifically, the other end of the first terminal 91 protrudes from the insulating case 260 toward the first terminal 91 side (+X side) in the direction of current flow. Furthermore, one end of the second terminal 92 is connected to the second end 52, and the other end is exposed to the outside from the insulating case 260. Specifically, the other end of the second terminal 92 protrudes from the insulating case 260 toward the second terminal 92 side (-X side) in the direction of current flow.

[0144] (Insulating material) Multiple insulating members 60 are provided in a vertical arrangement. In this embodiment, four insulating members 60 are arranged in parallel in the vertical direction. Each insulating member 60 is positioned in close proximity to or in contact with each fuse element 50. The insulating members 60 have openings or separation portions that extend in the width direction (Y direction).

[0145] Multiple insulating members 60 are arranged in contact with or in close proximity to the multiple fuse elements 50 and to the outside. More specifically, the multiple insulating members 60 include insulating members 60 arranged on the outside (upper side) of the outermost layer (fuse element 50f) on the shielding member 220 side (i.e., upper side) of the multiple fuse elements 50.

[0146] However, this is not limited to this configuration. Although not specifically shown in the diagram, the uppermost insulating member 60 may be formed integrally with the second retaining member 260Bb and constitute a part of the second retaining member 260Bb. In this case, the multiple insulating members 60 are arranged in contact with or close to the multiple fuse elements 50. The openings or separations of each of the multiple insulating members 60 overlap each other when viewed from a vertical direction.

[0147] (Shielding material) The shielding member 220 is positioned above the fuse element 50. When the restriction on downward movement by the locking member 270, which will be described later, is released, the shielding member 220 can move downward while being inserted into the opening or separation portion of the insulating member 60 so as to cleave the fuse element 50 by the pressing force (which may be rephrased as stress or biasing force) of the pressing means 230.

[0148] Furthermore, the vertical direction in which the shielding member 220 moves is also the direction in which the shielding member 220 is inserted into the opening or separation portion of the insulating member 60, and can therefore be referred to as the insertion direction. In other words, the shielding member 220 is movable in the insertion direction.

[0149] The shielding member 220 has a convex portion 220a and a pressing means support portion 220b. The convex portion 220a is plate-shaped and extends in the direction perpendicular to the current-carrying direction (X direction) (YZ plane). The upper end of the convex portion 220a is connected to the pressing means support portion 220b. The pressing means support portion 220b is substantially plate-shaped and extends in the direction perpendicular to the vertical direction (Z direction) (XY plane).

[0150] The convex portion 220a protrudes downward from the pressing means support portion 220b. More specifically, the convex portion 220a protrudes in the insertion direction toward the opening or separation portion of the insulating member 60 and the fuse element 50.

[0151] The convex portion 220a has a tip 220aa located at its lower end and extending in the width direction (Y direction). The tip 220aa may also be referred to as the blade portion 220aa. In a cross section perpendicular to the width direction (XZ cross section), the tip 220aa has a V-shape that is convex downwards.

[0152] The pressing means support portion 220b has a recess 220ba and a first step portion 225. That is, the shielding member 220 has the first step portion 225. The recess 220ba is recessed downward from the upper surface of the pressing means support portion 220b.

[0153] As shown in Figure 18, the first stage portion 225 protrudes from the outer surface of the pressing means support portion 220b. Specifically, in this embodiment, the first stage portion 225 is provided on each (i.e., a pair) of the outer surface of the pressing means support portion 220b, on both sides facing outward in the direction of current flow (X direction).

[0154] The first stage portion 225 faces the insertion direction of the shielding member 220, specifically facing downwards. In the insertion direction (up and down direction), the first stage portion 225 and the second stage portion 263 face opposite each other. When viewed from the insertion direction, the first stage portion 225 and the second stage portion 263 do not overlap each other.

[0155] (Pressing means) As shown in Figure 16, the pressing means 230 is positioned above the shielding member 220. Specifically, the pressing means 230 is positioned between the upper surface of the pressing means support portion 220b and the lower surface of the third holding member 260Bc. The pressing means 230 is a spring (biasing member) such as an elastically deformable compression coil spring, and in this embodiment, it has a substantially conical shape that expands in diameter downwards.

[0156] The lower part of the pressing means 230 is positioned (housed) in the recess 220ba provided on the upper surface of the pressing means support portion 220b. The upper part of the pressing means 230 is positioned (housed) in the pressing means housing recess 262 provided on the lower surface of the third holding member 260Bc.

[0157] The pressing means 230 presses the shielding member 220 in the insertion direction (downward). Specifically, the pressing means 230 is assembled inside the protective element 250 in a state where it has been elastically deformed by contracting in the vertical direction, and the pressing force (stress, biasing force) due to the restoring deformation force presses the pressing means support portion 220b downward.

[0158] (Heating element, power supply component) As shown in Figures 16 and 18, the heating element 80 is plate-shaped, and its pair of surfaces (front and back) face the direction of current flow (X direction). The heating element 80 is placed (housed) in the heating element housing recess 261. The heating element 80 is provided in each of the pair of heating element housing recess 261 (i.e., a pair). In this embodiment, the heating element 80 heats and softens the locking member 270. If the heating element housing recess 261 is located on the inner surface of the side wall of the second holding member 260Bb, facing inward (towards the center) in the width direction (Y direction) perpendicular to the current direction (X direction), then the heating element 80 is positioned in a orientation that matches the heating element housing recess 261. In other words, in this case, the pair of surfaces of the heating element 80 face in the width direction (Y direction). If one heating element housing recess 261 is located on one side, one heating element 80 is provided in the heating element housing recess 261. The power supply component 90 supplies current to the heating element 80.

[0159] (locking member) The locking member 270 in this embodiment is formed, for example, by plating a rectangular plate-shaped solder material with Ag. The locking member 270 is positioned adjacent to the heating element 80. The locking member 270 and the heating element 80 are positioned facing each other, and in this embodiment, the direction in which these members face each other is the direction of current flow (X direction). The pair of surfaces of the locking member 270 (front surface and back surface) face the direction of current flow (X direction). When viewed from the width direction (Y direction), the dimension L2 of the locking member 270 in the insertion direction (Z direction) is larger than the dimension L1 of the locking member 270 in the direction of current flow (dimension in the direction from the heating element 80 toward the locking member 270). Although not specifically shown in the figures, in this embodiment, the dimension of the locking member 270 in the width direction (Y direction) is larger than dimensions L1 and L2. That is, the locking member 270 is a rectangular plate shape with the width direction as the longitudinal direction. If the heat-generating element housing recess 261 is located on the inner surface of the side wall of the second holding member 260Bb, facing inward (towards the center) in the width direction (Y direction) perpendicular to the energizing direction (X direction), then the locking member 270 is positioned in a orientation that matches the heat-generating element housing recess 261. That is, in this case, the pair of surfaces of the locking member 270 face in the width direction (Y direction), and the direction in which the locking member 270 and the heat-generating element 80 face each other is the width direction (Y direction). Also in this case, when viewed from the energizing direction (X direction), the dimension L2 of the locking member 270 in the insertion direction (Z direction) is greater than the dimension L1 of the locking member 270 in the width direction (Y direction) (the dimension in the direction from the heat-generating element 80 toward the locking member 270).

[0160] A pair of locking members 270 are provided, arranged adjacent to a pair of heating elements 80. One of the pair of surfaces (front and back) of each locking member 270 is positioned in close proximity to or in contact with the heating element 80. The other of the pair of surfaces of the locking member 270 is positioned in close proximity to or in contact with the outer surface of the pressing means support portion 220b of the shielding member 220. If there is one heating element housing recess 261 on one side, the locking member 270 is positioned adjacent to one heating element 80.

[0161] Furthermore, the pair of end faces of the locking member 270 facing the insertion direction (up and down direction) are sandwiched between the first stage portion 225 and the second stage portion 263. That is, in the insertion direction, the locking member 270 is sandwiched and supported between the pressing means support portion 220b of the shielding member 220 and the second holding member 260Bb of the insulating case 260. In this way, the locking member 270 is sandwiched and locked between the insulating case 260 and the shielding member 220 in the insertion direction of the shielding member 220. In other words, the locking member 270 is locked between the insulating case 260 and the shielding member 220, and the movement of the shielding member 220 is suppressed.

[0162] Figures 17 and 19 are cross-sectional views (XZ cross-sectional views) showing the protective element 250 or a part thereof, representing the state in which the shielding member 220 has moved downward in the insertion direction. When power is supplied from the power supply member 90 to the heating element 80, the heating element 80 generates heat. When the heating element 80 generates heat, this heat softens the locking member 270. As the locking member 270 softens, the shielding member 220 moves while separating the locking member 270 due to the pressing force of the pressing means 230. Specifically, as shown in Figure 19 for example, the softened locking member 270 is separated into the heating element 80 side and the shielding member 220 side. This makes it possible for the shielding member 220 to move downward.

[0163] When the restriction on the downward movement of the shielding member 220 by the locking member 270 is released, the shielding member 220 moves downward due to the pressing force of the pressing means 230. The shielding member 220 cuts the fuse element 50 by moving through the opening or separation portion of the insulating member 60, thereby interrupting the current flow to the fuse element 50. The shielding member 220 also cuts the fuse element 50 and shields the cut parts of the fuse element 50 from each other in the direction of current flow of the fuse element 50.

[0164] As shown in Figure 17, in this embodiment, as the shielding member 220 moves downward, the tip 220aa of the convex portion 220a is positioned within the groove 14. That is, the tip 220aa of the shielding member 220 in the insertion direction is insertable into the groove 14. The shielding member 220 is movable within all openings or separation portions of the insulating member 60, and in this embodiment, it is also movable within the groove 14.

[0165] Here, Figures 20 and 21 show a cross-sectional view (XZ cross-sectional view) of a part of the protective element 250 of a modified example of this embodiment. In this modified example, instead of the aforementioned locking member 270, a pair of locking members 271 made of, for example, copper plates, and a fixing member 272 made of, for example, solder, are used, which are placed between the pair of locking members 271 to fix them in place. In this modified example, the heating element 80 heats and softens the fixing member 272.

[0166] As the fixing member 272 softens, the pressing force of the pressing means 230 causes the shielding member 220 to move while separating it from the fixing member 272. Specifically, as shown in Figure 21, for example, the softened fixing member 272 is separated into one side of the pair of locking members 271 that sandwich the fixing member 272 and the other side of the locking member 271. This allows the shielding member 220 to move downward.

[0167] In the protective element 250 of this embodiment, if an overcurrent exceeding the rated current flows through the fuse element 50, the fuse element 50 is thermally melted and the current path is interrupted. In addition, by passing current through the heating element 80, the locking member 270 or fixing member 272 that suppresses the movement of the shielding member 220 is softened, and the shielding member 220 is moved by the pressing force of the pressing means 230, thereby physically cutting the fuse element 50 and interrupting the current path.

[0168] In this embodiment, the fuse element 50 and the insulating member 60 are in close proximity or in contact, preferably in close contact. As a result, there is no space between the fuse element 50 and the insulating member 60 where arc discharge can continue, and the arc discharge is reliably extinguished. In this embodiment, the locking members 270 and 271 are not located near the fuse element 50, but are provided between the insulating case 260 and the shielding member 220, and by being locked to these members, they restrict the downward movement of the shielding member 220.

[0169] Therefore, the locking members 270 and 271 can be positioned away from components that may experience a temperature rise when the protective element 250 is energized (during normal use), such as the fuse element 50 and the insulating member 60. This prevents the function of the locking members 270 and 271 from being affected by the temperature rise of each component.

[0170] Furthermore, since the pressing force of the pressing means 230 is not transmitted to the fuse element 50 or the insulating member 60 via the locking members 270 and 271, the functions of the fuse element 50 and the insulating member 60 are also maintained well over a long period of time.

[0171] Furthermore, the tip 220aa of the convex portion 220a of the shielding member 220 can be positioned closer to the fuse element 50 and the insulating member 60. This makes it possible to reduce the external dimensions of the insulating case 260 in the vertical direction (insertion direction, thickness direction), and enables miniaturization of the protective element 250.

[0172] As described above, according to this embodiment, a large arc discharge is less likely to occur when the fuse element 50 blows, the size of the insulating case 260 can be made smaller and lighter, and a protection element 250 that can simultaneously perform overcurrent interruption for high voltage and high current and interruption by an interruption signal is provided.

[0173] In this embodiment, the heat generated by the heating element 80 softens the locking member 270 or the fixing member 272, causing the shielding member 220 to move downward while separating the locking member 270 or the fixing member 272 due to the pressing force of the pressing means 230. Since the restriction on the downward movement of the shielding member 220 is stably released, the current to the fuse element 50 can be interrupted more reliably.

[0174] In this embodiment, when the shielding member 220 moves downward, the tip 220aa of the convex portion 220a is inserted into the groove 14 of the inner bottom surface 13 of the insulating case 260. This ensures that the fuse element 50 that is close to or in contact with the inner bottom surface 13 is reliably cut by the shielding member 220.

[0175] In this embodiment, when viewed from the width direction (Y direction), the dimension L2 of the locking member 270 in the insertion direction is larger than the dimension L1 of the locking member 270 in the energizing direction (dimension in the direction from the heating element 80 toward the locking member 270). Alternatively, when viewed from the energizing direction (X direction), the dimension L2 of the locking member 270 in the insertion direction is larger than the dimension L1 of the locking member 270 in the width direction (dimension in the direction from the heating element 80 toward the locking member 270). According to the above configuration, the shear force in the insertion direction of the locking member 270 is increased, so that the locking member 270 can be stably held (locked) between the insulating case 260 and the shielding member 220.

[0176] In this embodiment, the pair of end faces of the locking members 270 and 271 facing the insertion direction are sandwiched between the first step portion 225 and the second step portion 263, and when viewed from the insertion direction, the first step portion 225 and the second step portion 263 do not overlap each other. With the above configuration, when the fixing member 272 that fixes the locking member 270 or the locking member 271 softens and the shielding member 220 moves downward due to the pressing force of the pressing means 230, the first stage portion 225 and the second stage portion 263 that held the locking members 270 and 271 pass each other reliably in the insertion direction. Therefore, the downward movement of the shielding member 220 is not hindered by the first stage portion 225 and the second stage portion 263, and the current of the fuse element 50 is reliably interrupted.

[0177] (modified version) Figure 22 is a cross-sectional view (XZ cross-sectional view) showing a part of the protective element 250 of a modified embodiment. In this modified embodiment, one or both of the two retaining members 260Ba and 260Bb of the insulating case 260 are integrally formed with the insulating member 60. In the illustrated example, one of the two retaining members 260Ba and 260Bb (retaining member 260Bb) is integrally formed with the insulating member 60. Also, only one fuse element 50 is provided.

[0178] In the above configuration, the insulating member 60 is integrated with the retaining members 260Ba and 260Bb. Therefore, the number of parts can be reduced, making it easier to manufacture the protective element 250 and reducing manufacturing costs.

[0179] (modified version) Figure 23 is a schematic diagram of a modified fuse element 550 according to the embodiment, and is a plan view corresponding to Figure 4(a). In this modified example, the fuse element 550 has a first fusible conductor 555 and a second fusible conductor 553 having a lower melting point than the first fusible conductor 555. Furthermore, the first fusible conductor 555 and the second fusible conductor 553 are connected in series when energized. That is, the first fusible conductor 555 and the second fusible conductor 553 are electrically connected in series and are arranged side by side in the direction of energization (X direction) in this modified example. Furthermore, the first fusible conductor 555 and the second fusible conductor 553 may be arranged side by side in the insertion direction (Z direction). In detail, although not shown in the figures, the fuse element 550 may overlap the inner (center side) tips of the two first fusible conductors 555 in the current-carrying direction (X direction), and connect the gap in the overlap with the second fusible conductor 553. That is, the tips of the two first fusible conductors 555 and the one second fusible conductor 553 located between these tips are arranged to overlap when viewed from the insertion direction (Z direction), and the first fusible conductor 555 and the second fusible conductor 553 may be connected in series (electrically) when current is carried out. This structure allows for a shorter current-carrying distance for the second fusible conductor 553, which has a higher electrical resistivity than the first fusible conductor 555, thereby suppressing an increase in the electrical resistance of the fuse element 550.

[0180] Furthermore, the second fusible conductor 553 is positioned between the two first fusible conductors 555. According to the above configuration, the second fusible conductor 553 is placed in the center of the fuse element 550 in the direction of current flow, allowing the fuse element 550 to be blown open from the center.

[0181] In this modified example, when a current exceeding the rated value flows through the current path of the fuse element 550, the second fusible conductor 553 melts before the first fusible conductor 555, thus stabilizing the position of the part of the fuse element 550 that interrupts the current. This makes it possible to interrupt the current flow in the fuse element 550 without damaging the insulating material 60 or the insulating case 260, from currents of 1.5 to 2 times the rated value to explosive interruptions at 10 times or more the rated value.

[0182] Furthermore, the heat generated by the heating element 80 causes the shielding member 220 to move, and the second fusible conductor 553 is cut. With the above configuration, the downward movement of the shielding member 220 causes the second fusible conductor 553, which has a lower melting point, to be cut within the fuse element 550. Even if it takes time for the second fusible conductor 553 to melt when an overcurrent flows, the shielding member 220 can reliably cut the fuse element 550. Furthermore, in the case where the fuse element 550 is configured such that the tips of two first fusible conductors 555 overlap and are connected by a second fusible conductor 553, the downward movement of the shielding member 220 causes the first fusible conductors 555 to be cut. In this case, it is preferable that the cut portion of the first fusible conductor 555 has a smaller cross-sectional area than the portion of the first fusible conductor 555 other than the cut portion.

[0183] The protective element of the present invention is not limited to the embodiments described above.

[0184] The present invention may be combined in any way that does not depart from the spirit of the invention, as described in the above embodiments, modifications, and reference examples, and the configurations may be added, omitted, substituted, or otherwise modified. Furthermore, the present invention is not limited by the above embodiments, etc., but is limited only by the claims. [Explanation of Symbols]

[0185] 10,11,260…Insulating Cases 20, 120, 220… Shielding members 30,230… Pressing means 50,550…Fuse element 51...First end 52…Second end 60, 60A, 60B, 160A… Insulating materials 64,65…separation part 64A,65A…Opening 70,70A,70B,70C,71,170,270,271...Locking member 80… Heating element 90, 90a, 90b, 90c, 90d, 90e, 90f, 90A… Power supply components 91...1st terminal 92…Second terminal 100, 200, 250… Protective elements 272… Fixing member 555...First fusible conductor 553...Second fusible conductor

Claims

1. It comprises a fuse element, an insulating case housing the fuse element, a first terminal, and a second terminal. Furthermore, an insulating member is positioned in close proximity to or in contact with the fuse element, and has an opening or separation portion formed therein. A shielding member that is movable in the insertion direction and inserted into the opening or separation portion of the insulating member so as to interrupt the fuse element, A pressing means for pressing the shielding member in the insertion direction of the shielding member, A locking member is engaged between the insulating case and the shielding member to restrain the movement of the shielding member, A heating element that heats and softens the locking member or the fixing member that secures the locking member, The heating element has a power supply member that supplies current, The fuse element has a first end and a second end facing each other, the first terminal has one end connected to the first end and the other end exposed to the outside from the insulating case, and the second terminal has one end connected to the second end and the other end exposed to the outside from the insulating case. The insulating case further comprises a protective element that houses the insulating member, the shielding member, the pressing means, the locking member, the heating element, and a part of the power supply member.

2. As the heating element generates heat and the locking member or fixing member softens, the shielding member moves while separating from the locking member or fixing member due to the pressing force of the pressing means. Furthermore, the protective element according to claim 1, wherein the shielding member moves over the opening or separation portion of the insulating member to cut the fuse element, thereby interrupting the current flow to the fuse element.

3. The protective element according to claim 2, wherein the shielding member cuts the fuse element and shields the cut portions of the fuse element from each other in the direction of current flow of the fuse element.

4. The protective element according to any one of claims 1 to 3, wherein the pressing means is a spring.

5. The protective element according to any one of claims 1 to 3, wherein at least one of the insulating member, the shielding member, and the insulating case is made of a material with a tracking resistance index CTI of 500V or higher.

6. The protective element according to any one of claims 1 to 3, wherein at least one of the insulating member, the shielding member, and the insulating case is formed of a resin material selected from the group consisting of polyamide resins and fluororesins.

7. The protective element according to any one of claims 1 to 3, wherein the fuse element is a laminate comprising a low-melting-point metal layer and a high-melting-point metal layer, the low-melting-point metal layer comprising tin, and the high-melting-point metal layer comprising silver or copper.

8. The protective element according to claim 7, wherein the fuse element is a laminate having two or more high-melting-point metal layers and one or more low-melting-point metal layers, the low-melting-point metal layers being disposed between the high-melting-point metal layers.

9. The protective element according to any one of claims 1 to 3, wherein the fuse element is a single layer containing silver or copper.

10. The protective element according to any one of claims 1 to 3, wherein the fuse element has a fusible portion between the first end and the second end, and the cross-sectional area of ​​the fusible portion in the direction of current flow is smaller than the cross-sectional area of ​​the first end and the second end in the direction of current flow from the first end to the second end.

11. The fuse element comprises a first fusible conductor and a second fusible conductor having a lower melting point than the first fusible conductor. The protective element according to any one of claims 1 to 3, wherein the first fusible conductor and the second fusible conductor are connected in series when energized.

12. The protective element according to claim 11, wherein the second fusible conductor is disposed between the two first fusible conductors.

13. The protective element according to claim 11, wherein the shielding member moves due to the heat generated by the heating element, and the second fusible conductor is cut.

14. The insulating case has an inner bottom surface that is positioned in close proximity to or in contact with the side of the fuse element opposite to the shielding member. The inner bottom surface has a groove that extends along the opening or separation portion of the insulating member. The protective element according to any one of claims 1 to 3, wherein the tip of the shielding member in the insertion direction is insertable into the groove.

15. A plurality of fuse elements are stacked in parallel in a direction perpendicular to the surface of the plate-shaped fuse element, It comprises a plurality of insulating members arranged in contact with or in close proximity to a plurality of fuse elements, The protective element according to any one of claims 1 to 3, wherein the openings or separation portions of each of the plurality of insulating members overlap each other when viewed from a vertical direction, and the shielding member is movable within all of the openings or separation portions.

16. The plurality of insulating members include insulating members that are positioned outside the outermost layer on the shielding member side of the plurality of fuse elements, The insulating case has an inner bottom surface that is positioned in close proximity to or in contact with the outermost layer of the plurality of fuse elements opposite to the shielding member, The inner bottom surface has a groove that extends along the opening or separation portion of the insulating member. The protective element according to claim 15, wherein the shielding member is movable within all of the openings, separation portions and grooves.

17. A plurality of fuse elements are stacked in parallel in a direction perpendicular to the surface of the plate-shaped fuse element, It comprises a plurality of insulating members arranged between and in contact with or in close proximity to the outside of the plurality of fuse elements, The protective element according to any one of claims 1 to 3, wherein the openings or separation portions of each of the plurality of insulating members overlap each other when viewed from a vertical direction, and the shielding member is movable within all of the openings or separation portions.

18. The insulating case has at least two retaining members positioned on both sides of the fuse element in a direction perpendicular to the surface of the plate-shaped fuse element, The protective element according to any one of claims 1 to 3, wherein one or both of the two retaining members are formed integrally with the insulating member.

19. The locking member is sandwiched and locked between the insulating case and the shielding member in the insertion direction of the shielding member. A protective element according to any one of claims 1 to 3, wherein, when viewed from a width direction perpendicular to the current-carrying direction of the fuse element and the insertion direction of the shielding member, or when viewed from the current-carrying direction, the dimension of the locking member in the insertion direction is greater than the dimension of the locking member in the direction toward the locking member from the heating element.

20. The shielding member has a first stage portion facing the insertion direction of the shielding member, The insulating case has a second stage that faces the opposite side from the first stage in the insertion direction. The pair of end faces of the locking member facing the insertion direction are sandwiched between the first step and the second step. The protective element according to any one of claims 1 to 3, wherein, when viewed from the insertion direction, the first stage and the second stage do not overlap with each other.

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