Protective element

Abstract

This protective element comprises a second conductor (312) and a first conductor (211) having at least one first tip portion (211a). The first tip portion (211a) has a shape in which the cross-sectional area decreases from the root toward the tip. At least part of the first tip portion (211a) and at least part of the second conductor (312) are connected to a fusible conductor (13) having a lower fusing temperature than each of the first conductor (211) and the second conductor (312).

Description

Protection Elements

[0001] The present invention relates to a protection element. The present invention claims priority based on Japanese Patent Application No. 2023-201237, filed on November 29, 2023, the contents of which are incorporated herein by reference.

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

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

[0004] The following technologies are known for forming heat spots in a foil-shaped fuse element by using holes, thickness variations, notches, etc., to melt the fuse element in the event of an overcurrent. For example, Patent Document 1 discloses a fuse in which the thickness of the interrupting portion of a conductive thin-film pattern formed on an insulating substrate is set to be thinner than the thickness of the connecting portions connected in series to the interrupting portion. For example, Patent Documents 2 and 3 disclose fuse elements in which the fusing portion is formed by punching holes in multiple elements arranged in parallel. For example, Patent Documents 4 and 5 disclose fuses in which the thickness of the interrupting portion, in a conductive thin-film pattern formed on the surface of an insulating substrate, is thinner than the thickness of the connecting bands connected in series to the interrupting portion.

[0005] Japanese Patent No. 6057413 Japanese Patent No. 6199368 Japanese Patent No. 5952751 Japanese Patent No. 5116119 Japanese Patent No. 4998890

[0006] Protective devices capable of interrupting high voltages and large currents generally use fuse elements made by processing a portion of inexpensive, low-resistivity metal foil, such as copper foil, into a punched metal. While these fuse elements have sufficient interruption performance in the high-current range, they may have an interruption time that is too long or may not be able to interrupt at all in the relatively low-current range (e.g., about two to three times the rated current).

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a protection element that can handle high voltage and large current interruption and can shorten the overcurrent interruption time.

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

[0009] [Aspect 1] A protective element comprising a first conductor having at least one first tip portion, and a second conductor, wherein the first tip portion has a shape in which the cross-sectional area decreases from the base to the tip, and at least a portion of the first tip portion and the second conductor are connected to a fusible conductor having a lower melting temperature than each of the first conductor and the second conductor.

[0010] [Aspect 2] The second conductor has at least one second tip, and the second tip has a shape in which the cross-sectional area decreases from the base to the tip, and at least a portion of the first tip and the second tip is connected to the fusible conductor. A protective element as described in aspect 1.

[0011] [Aspect 3] The protection element according to aspect 2, wherein the first tip portion and the second tip portion face each other and are close to or in contact with each other.

[0012] [Aspect 4] The protection element according to any one of Aspects 1 to 3, wherein each of the first conductor and the second conductor is a plate-shaped member made of metal.

[0013] [Aspect 5] A protective element according to any one of aspects 1 to 4, wherein each of the first conductor and the second conductor is made of Ag or Cu, or a metal containing Ag or Cu as a main component.

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

[0015] [Aspect 7] The protective element according to any one of aspects 1 to 5, wherein the fusible conductor is a laminate including a high melting point metal layer and a low melting point metal layer.

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

[0017] [Aspect 9] The first conductor has a plurality of the first tip portions, the second conductor has a plurality of the second tip portions, and the plurality of the first tip portions and the plurality of the second tip portions are opposed to each other and are connected to the fusible conductor in a state of close proximity or contact. A protective element as described in aspect 2 or 3.

[0018] [Aspect 10] A protection element according to Aspects 2, 3, or 9, further comprising a first terminal and a second terminal, wherein a portion of the first conductor is electrically connected to the first terminal, and a portion of the second conductor is electrically connected to the second terminal.

[0019] [Aspect 11] The first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form one unit, and multiple units are electrically connected in series. A protective element as described in aspect 10.

[0020] [Aspect 12] The first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form one unit, and multiple units are electrically connected in parallel. A protective element as described in aspect 10 or 11.

[0021] [Aspect 13] A protective element according to any one of aspects 2, 3, and 9 to 12, further comprising a case, wherein the first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form a single unit, and the case contains a portion of the first terminal and the second terminal and one or more of the units, and at least a portion of the gap within the case is filled with a filler material.

[0022] [Aspect 14] The protective element according to aspect 13, wherein the filler includes an arc-extinguishing agent, silica sand, inorganic fiber material, ceramic fiber, or silicone resin.

[0023] [Aspect 15] A protective element according to any one of aspects 2, 3, and 9 to 12, further comprising a case, wherein the first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form a single unit, and each of the first conductor and the second conductor is a metal plate-shaped member, and the case contains a portion of the first terminal and the second terminal and one or more of the units, and is in close proximity to or in contact with both surfaces of one or more of the units.

[0024] [Aspect 16] The protective element according to any one of aspects 2, 3, 9 to 12, further comprising a case and one or more insulating members, wherein the first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form a single unit, each of the first conductor and the second conductor is a metal plate-shaped member, and one or more of the insulating members are in close proximity to or in contact with both surfaces of one or more of the units. The case contains a portion of the first terminal and the second terminal, one or more of the units, and one or more of the insulating members. An internal pressure buffering space is formed between the case and the insulating member, and a flow path is formed in the insulating member and / or the case to release high-temperature gas generated between the internal pressure buffering space and the unit when the unit is shut off.

[0025] [Aspect 17] The protective element according to aspect 16, wherein the insulating member is made of a nylon-based resin or a fluorine-based resin.

[0026] [Aspect 18] The protective element according to aspect 16 or 17, wherein a filler is sealed in the internal pressure buffering space.

[0027] [Aspect 19] The protective element according to aspect 18, wherein the filler comprises an arc-extinguishing agent, silica sand, inorganic fiber material, ceramic fiber, or silicone resin.

[0028] [Aspect 20] A protection element described in any one of aspects 13 to 19, wherein the case includes a plurality of holding members and further includes an outer shell member that covers the outside of the case and fixes the plurality of holding members.

[0029] According to the present invention, it is possible to provide a protection element that can handle high voltage and large current interruption and can shorten the overcurrent interruption time.

[0030] 11A and 11B are plan views showing a protection element of a first embodiment before shutdown; a plan view showing a protection element of a first embodiment after shutdown; a plan view showing a protection element of a second embodiment before shutdown; a plan view showing a protection element of a second embodiment after shutdown; a plan view showing a protection element of a third embodiment before shutdown; a plan view showing a protection element of a third embodiment after shutdown; a plan view showing a protection element of a fourth embodiment before shutdown; a cross-sectional view taken along VIII-VIII in FIG. 7; a plan view showing a protection element of a fifth embodiment before shutdown; a cross-sectional view taken along X-X in FIG. 9; a plan view showing a protection element of a sixth embodiment before shutdown; a cross-sectional view taken along XII-XII in FIG. 11; a plan view showing a protection element of a seventh embodiment before shutdown; a cross-sectional view taken along XIV-XIV in FIG. 13; a cross-sectional view taken along XV-XV in FIG. 16; a cross-sectional view taken along XVI-XVI in FIG. 15; 16. A side view showing the protection element of the eighth embodiment, taken along the arrow XVII in FIG. 16. A view showing the protection element of the ninth embodiment, taken along the XVIII-XVIII cross-section in FIG. 19. A view showing the protection element of the ninth embodiment, taken along the XIX-XIX cross-section in FIG. 18. A side view showing the protection element of the ninth embodiment, taken along the arrow XX in FIG. 19.

[0031] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the effects of the present invention.

[0032] First Embodiment A protection element according to one embodiment of the present invention will be described with reference to Figures 1 and 2. The protection element according to this embodiment constitutes part of a high-voltage, high-current (100 V / 100 A or more) electric circuit that uses, for example, a lithium-ion secondary battery, and / or part of a current circuit in a relatively small current range (for example, about two to three times the rated current). The protection element is mounted, for example, on an electric vehicle (EV).

[0033] As shown in FIG. 1, the protective element includes a first conductor 11 having at least one first tip 11a and a second conductor 12 having at least one second tip 12a. In the illustrated example, the protective element includes a first conductor 11 having only one first tip 11a and a second conductor 12 having only one second tip 12a, but this is not limited to this. For example, the protective element may include a first conductor 11 having two or more first tip portions 11a and a second conductor 12 having two or more second tip portions 12a. For example, the arrangement of the first tip portion 11a and the second tip portion 12a can be changed depending on the design specifications. The illustrated example shows an example of one unit 1 constituting the protective element. The unit 1 is formed by a first conductor 11 and a second conductor 12, in which the first tip portion 11a and the second tip portion 12a are connected to a fusible conductor 13.

[0034] Each of the first tip 11a and the second tip 12a has a shape in which the cross-sectional area decreases from the base to the tip. At least a portion of the first tip 11a and the second tip 12a is connected to a soluble conductor 13 having a lower melting temperature than each of the first conductor 11 and the second conductor 12. In the example shown in the figure, the tip of the first tip 11a and the tip of the second tip 12a are each connected to the soluble conductor 13. The first tip 11a and the second tip 12a face each other. Each of the first conductor 11 and the second conductor 12 has a plate shape.

[0035] The first conductor 11 and the second conductor 12 constitute a fuse element 10. The illustrated example shows a cut-out portion of the fuse element 10. The protective element has an overcurrent interrupter, as a mechanism for interrupting a current path, that melts the fuse element 10 to interrupt the current path when an overcurrent (current equal to or greater than a predetermined value) that exceeds the rated current flows through the fuse element 10.

[0036] Hereinafter, each configuration may be described using an XYZ Cartesian coordinate system (three-dimensional Cartesian coordinate system) in each figure. The direction in which the first tip portion 11a and the second tip portion 12a face each other is referred to as the front-rear direction. The front-rear direction corresponds to the X-axis direction in each figure. Within the X-axis direction, the direction from the second tip portion 12a to the first tip portion 11a (-X side) is referred to as the front side, and the direction from the first tip portion 11a to the second tip portion 12a (+X side) is referred to as the rear side. Note that the front-rear direction is the direction connecting the first terminal to which the first conductor 11 is connected and the second terminal to which the second conductor 12 is connected. Because this is also the direction in which electricity flows when the protection element is in use, it may also be referred to as the current flow direction.

[0037] The direction in which the plate surfaces of the first conductor 11 and the second conductor 12 face is referred to as the up-down direction. The up-down direction is a direction perpendicular to the front-rear direction and corresponds to the Z-axis direction in each drawing. In the up-down direction, the upper side corresponds to the +Z side, and the lower side corresponds to the -Z side.

[0038] The direction perpendicular to the front-rear direction and the up-down direction is called the left-right direction. The left-right direction corresponds to the Y-axis direction in each drawing. In the left-right direction, the left side corresponds to the -Y side, and the right side corresponds to the +Y side. Specifically, the -Y side is the left side when the protective element is viewed from the rear (+X side), and the +Y side is the right side when the protective element is viewed from the rear. The left-right direction may also be referred to as the width direction. In this case, for example, one side in the width direction corresponds to the -Y side, and the other side in the width direction corresponds to the +Y side.

[0039] In this embodiment, the terms "front side," "rear side," "upper side," "lower side," "left side," and "right side" are convenient names for clearly explaining the relative positional relationships of each component, and the actual positional relationships may be other than those indicated by these names.

[0040] The fuse element 10 has a first conductor 11, a fusible conductor 13, and a second conductor 12 connected in series in the current flow direction (the direction of the arrow in the figure). The fusible conductor 13 is made of a material with a lower melting temperature than each of the first conductor 11 and the second conductor 12. The fusible conductor 13 also has a higher electrical resistivity than each of the first conductor 11 and the second conductor 12. The fusible conductor 13 functions as a fusing portion of the fuse element 10 when an overcurrent is interrupted.

[0041] In the illustrated example, the first tip portion 11a and the second tip portion 12a are opposed to and close to each other. Alternatively, the first tip portion 11a and the second tip portion 12a may be opposed to and in contact with each other. For example, the manner in which the first tip portion 11a and the second tip portion 12a are in close proximity to each other can be changed according to design specifications.

[0042] In the present embodiment, each of the first conductor 11 and the second conductor 12 is a plate-like member made of metal. The first conductor 11 and the second conductor 12 may also be in the form of a sheet or foil. In the example shown in the figure, each of the first conductor 11 and the second conductor 12 includes a portion (root portion) that is a substantially rectangular plate-like member whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction, and a tip portion (first tip portion 11 a and second tip portion 12 a) that tapers from the root portion toward the tip.

[0043] In the example shown in the figure, each of the first tip portion 11a and the second tip portion 12a has a shape in which the left-right dimension decreases from the base to the tip when viewed from the top-bottom direction, and the outer edge in the left-right direction is curved inward. In this embodiment, each of the first tip portion 11a and the second tip portion 12a has a uniform vertical dimension (thickness) from the base to the tip, but the left-right dimension decreases from the base to the tip, resulting in a shape in which the cross-sectional area decreases from the base to the tip. Note that the cross-sectional area corresponds to the area when the tip portion is cut along a plane (YZ plane) perpendicular to the front-back direction (current flow direction).

[0044] In this embodiment, each of the first conductor 11 and the second conductor 12 is made of Ag or Cu, or a metal mainly composed of Ag or Cu. When copper is used, it is preferable to apply an anti-rust treatment such as nickel plating, silver plating, or tin plating to the surface.

[0045] The first conductor 11, the fusible conductor 13, and the second conductor 12 are connected in series in this order to form a current path of the fuse element 10. The first tip 11a of the first conductor 11 and the second tip 12a of the second conductor 12 are connected to the fusible conductor 13 at their opposing tips in the current flow direction (approximately the front-to-back direction in the illustrated example) in which current flows through the fuse element 10.

[0046] The fusible conductor 13 extends in a plane direction (XY plane direction) perpendicular to the vertical direction so as to connect the respective tips of the first tip portion 11a and the second tip portion 12a. In the example shown in the figure, the fusible conductor 13 has a shape (for example, an elliptical or oblong shape) that is long in the front-to-rear direction when viewed from the top-to-bottom direction. The fusible conductor 13 is arranged in the center of the fuse element 10 in the front-to-rear direction. For example, flux may be applied to at least a portion of the surface of the fusible conductor 13.

[0047] In this embodiment, the soluble conductor 13 is made of Sn (tin) or a metal mainly composed of Sn. It is preferable to use a solder such as a Pb-free solder mainly composed of Sn as the metal used for the soluble conductor 13. Since Sn has a melting point of 217°C, solder mainly composed of Sn has a lower melting point than copper foil (melting point 1084°C), making it easier for the soluble conductor 13 to melt when an overcurrent is interrupted. For example, the first tip 11a of the first conductor 11 and the second tip 12a of the second conductor 12 are preferably joined by solder.

[0048] Next, an example of a method for manufacturing the fuse element 10 of this embodiment will be described. First, a plate material having outer dimensions larger than the outer dimensions of the entire plan view including the first conductor 11 and the second conductor 12 is cut from a metal plate (not shown). Note that the thickness of the cut metal plate may be adjusted by smoothing the portions corresponding to the first conductor 11 and the second conductor 12 with a hammer or the like.

[0049] Next, the cut metal plate is subjected to a punching process (pressing process) and / or a cutting process to obtain the first conductor 11 and the second conductor 12. The cut metal plate may be positioned in an automatic positioning punching machine, and punched using a punching machine whose blade edge has a planar shape that matches the overall shape of the first conductor 11 and the second conductor 12.

[0050] Next, the first tip portion 11a of the first conductor 11 and the second tip portion 12a of the second conductor 12 are joined together by soldering, thereby completing the manufacture of the fuse element 10 of this embodiment.

[0051] The protective element of the present embodiment described above includes a first conductor 11 having at least one first tip 11a and a second conductor 12 having at least one second tip 12a. Each of the first tip 11a and the second tip 12a has a shape in which the cross-sectional area decreases from the base to the tip. At least a portion of the first tip 11a and the second tip 12a is connected to a fusible conductor 13 having a lower melting temperature than each of the first conductor 11 and the second conductor 12. According to this configuration, since each of the first tip 11a and the second tip 12a has a shape in which the cross-sectional area decreases from the base to the tip, current is concentrated at the tip of each of the first tip 11a and the second tip 12a when an overcurrent is interrupted. In addition, since at least a portion of the first tip 11a and the second tip 12a are connected to the fusible conductor 13, which has a lower melting temperature than the first conductor 11 and the second conductor 12, the melting temperature of the fusing portion is lower than the melting points of the first conductor 11 and the second conductor 12, making the fusible conductor 13 more likely to melt. Therefore, the current concentration at the tip of each of the first tip 11a and the second tip 12a during overcurrent interruption, combined with the melting phenomenon of the fusible conductor 13, enables interruption in a relatively small current range (for example, about two to three times the rated current) and shortens the interruption time. Therefore, it is possible to provide a protective element that can handle high voltage and large current interruption and shorten the overcurrent interruption time.

[0052] In this embodiment, the first tip 11a and the second tip 12a are opposed to each other and are close to or in contact with each other. With this configuration, compared to when the first tip 11a and the second tip 12a are far apart from each other, current is more likely to concentrate at the tips of the first tip 11a and the second tip 12a when an overcurrent is interrupted, and the soluble conductor 13 is more likely to melt. Therefore, the overcurrent interruption time can be more effectively shortened.

[0053] In this embodiment, each of the first conductor 11 and the second conductor 12 is a metal plate-shaped member. With this configuration, the cross-sectional area of ​​each of the first tip portion 11 a and the second tip portion 12 a (the degree of current concentration at each tip) can be adjusted by changing the plate thickness of each of the first conductor 11 and the second conductor 12. In addition, each of the first tip portion 11 a of the first conductor 11 and the second tip portion 12 a of the second conductor 12 can be easily formed by punching (pressing) and / or cutting.

[0054] In this embodiment, each of the first conductor 11 and the second conductor 12 is made of Ag or Cu, or a metal primarily composed of Ag or Cu. This configuration tends to result in lower electrical resistivity compared to when each of the first conductor 11 and the second conductor 12 is a laminate including a high-melting-point metal layer and a low-melting-point metal layer. Therefore, the first conductor 11 and the second conductor 12 made of a single layer including Ag or Cu can be made thinner even when the same electrical resistance is maintained in the same area as a laminate including a high-melting-point metal layer and a low-melting-point metal layer. When the thickness of each of the first conductor 11 and the second conductor 12 is thin, the amount of molten material that flies off when the fuse element 10 melts is proportionally smaller, resulting in higher insulation resistance after interruption.

[0055] In this embodiment, the soluble conductor 13 is made of Sn or a metal mainly composed of Sn. According to this configuration, Sn has a lower melting point than Cu, etc., so the soluble conductor 13 is more likely to melt when an overcurrent is interrupted. Therefore, the overcurrent interruption time can be more effectively shortened.

[0056] For example, if the cross-sectional area of ​​each of the first and second tip portions were constant from the base to the tip and only a portion of each tip were connected with a fusible conductor, the resistance would likely be high and current would not flow easily. In contrast, in this embodiment, the cross-sectional area of ​​each of the first and second tip portions 11a and 12a decreases from the base to the tip, and the tips are connected with solder. This reduces the overall resistance of the fuse element 10 while allowing current to flow easily. Therefore, the current concentration at the tips of the first and second tip portions 11a and 12a during overcurrent interruption, combined with the melting of the fusible conductor 13, allows the fuse element 10 to be more effectively interrupted (melt the fusing portion) (see FIG. 2). Therefore, the overcurrent interruption time can be more effectively shortened.

[0057] The present invention is not limited to the above-described embodiment, and the configuration may be modified within the scope of the present invention, as described below. In the illustrations of other embodiments and modifications, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the following mainly describes the differences.

[0058] Second Embodiment A protection element according to a second embodiment of the present invention will be described with reference to Figures 3 and 4. The protection element of the second embodiment differs from the first embodiment described above mainly in the shapes of the first tip portion 211a and the second tip portion 212a. In each figure of this embodiment, components that are the same or substantially the same as those in the first embodiment may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0059] As shown in Figure 3, each of the first conductor 211 and the second conductor 212 has a substantially rectangular plate-shaped portion (root portion) whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction, and a tip portion (first tip portion 211a and second tip portion 212a) that tapers from the root portion toward the tip. The example in the figure shows an example of one unit constituting a protective element. The unit is formed by the first conductor 211 and the second conductor 212, whose first tip portion 211a and second tip portion 212a are connected to the fusible conductor 13.

[0060] In the illustrated example, each of the first tip portion 211a and the second tip portion 212a has a shape in which the left-right dimension decreases from the base to the tip when viewed from the top-bottom direction, and the outer edge in the left-right direction is linearly inclined toward the tip. In the illustrated example, each of the first tip portion 211a and the second tip portion 212a has a triangular shape that protrudes from the base to the tip when viewed from the top-bottom direction. In this embodiment, each of the first tip portion 211a and the second tip portion 212a has a uniform vertical dimension (thickness) from the base to the tip, but the left-right dimension decreases from the base to the tip, resulting in a shape in which the cross-sectional area decreases from the base to the tip.

[0061] In the protective element of the present embodiment described above, the cross-sectional area of ​​each of the first tip portion 211a and the second tip portion 212a decreases from the base to the tip, and the tips are connected with solder. This reduces the overall resistance of the fuse element while allowing current to flow easily. Therefore, when an overcurrent is interrupted, current concentration at the tips of the first tip portion 211a and the second tip portion 212a, combined with the melting of the fusible conductor, allows the fuse element to be more effectively interrupted (melts the fusing portion) (see FIG. 4). This effectively shortens the overcurrent interruption time.

[0062] Third Embodiment A protection element according to a third embodiment of the present invention will be described with reference to Figures 5 and 6. The protection element of the third embodiment differs from the first embodiment described above mainly in the shapes of the first tip portion 211a and the second tip portion 312a. In each drawing of this embodiment, components that are similar or substantially similar to those of the first and second embodiments may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0063] As shown in FIG. 5, the protective element includes a first conductor 211 having at least one first tip 211a and a second conductor 312. The first tip 211a has a shape in which the cross-sectional area decreases from the base to the tip. At least a portion of the first tip 211a and the second conductor 312 is connected to a fusible conductor 13 (e.g., solder) having a lower melting temperature than the first conductor 211 and the second conductor 312. The example shown in the figure shows an example of one unit constituting the protective element. The unit is formed by the first conductor 211 and the second conductor 312, whose first tip 211a and tip are connected to the fusible conductor 13.

[0064] 5, the first conductor 211 has a generally rectangular plate-like portion (root portion) whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction, and a tip portion (first tip portion 211a) that tapers from the root portion toward the tip. The second conductor 312 has a generally rectangular plate-like portion whose left-right dimension is shorter than its front-rear dimension when viewed from the top-bottom direction.

[0065] In the illustrated example, the first tip portion 211a has a shape in which the left-right dimension decreases from the base to the tip when viewed from the top-bottom direction, and the outer edge in the left-right direction is linearly inclined toward the tip. In the illustrated example, the first tip portion 211a has a triangular shape protruding from the base to the tip when viewed from the top-bottom direction. In this embodiment, the first tip portion 211a has a uniform vertical dimension (thickness) from the base to the tip, but the horizontal dimension decreases from the base to the tip, resulting in a shape in which the cross-sectional area decreases from the base to the tip. The second tip portion 312a has a uniform vertical dimension (thickness), the same horizontal dimension in the front-to-back direction, and a constant cross-sectional area in the front-to-back direction.

[0066] In the protective element of the present embodiment described above, the first tip portion 211a has a shape in which the cross-sectional area decreases from the base to the tip, and the tip of the first tip portion 211a is connected to the tip of the second conductor 312 with solder. This reduces the resistance of the fuse element as a whole while facilitating current flow. Therefore, current concentration at the tip of the first tip portion 211a during overcurrent interruption, combined with the melting of the fusible conductor, allows the fuse element to more effectively interrupt (melt the fusing portion) (see FIG. 6 ). This effectively shortens the overcurrent interruption time.

[0067] (Fourth embodiment) A protection element according to a fourth embodiment of the present invention will be described with reference to Figures 7 and 8. The protection element of the fourth embodiment differs from the first embodiment described above mainly in the number of first tip portions 11a and second tip portions 12a. In each figure of this embodiment, components that are the same or substantially the same as those of the first embodiment may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0068] 7 and 8, the first conductor 411 has a plurality of first tip portions 11a. The second conductor 412 has a plurality of second tip portions 12a. The plurality of first tip portions 11a and the plurality of second tip portions 12a face each other and are connected to the fusible conductor in a state of proximity or contact. The example shown in the figure shows an example of one unit constituting a protective element. The unit is formed by the first conductor 411 and the second conductor 412, in which the plurality of first tip portions 11a and the plurality of second tip portions 12a are connected to the fusible conductor 13.

[0069] In the illustrated example, the first conductor 411 has five first tip portions 11a, and the second conductor 412 has five second tip portions 12a, but this is not limited to this. For example, the first conductor 411 may have four or fewer first tip portions 11a or six or more first tip portions 11a, and the second conductor 412 may have four or fewer second tip portions 12a or six or more second tip portions 12a. For example, the number of first tip portions 11a and the number of second tip portions 12a may be the same or different. For example, the arrangement of the first tip portions 11a and the second tip portions 12a can be changed according to design specifications.

[0070] In the example shown in the figure, each of the first conductor 411 and the second conductor 412 has a portion (root portion) that is approximately rectangular plate-shaped and whose left-right dimension is longer than its front-to-back dimension when viewed from the top-to-bottom direction, and a plurality of tip portions (a plurality of first tip portions 11a and a plurality of second tip portions 12a) that taper from the root portion toward the tip.

[0071] In the illustrated example, each of the first tip portions 11 a and the second tip portions 12 a has a shape in which the dimension in the left-right direction decreases from the base to the tip when viewed from the top-bottom direction, and the outer edge in the left-right direction is curved inward. In this embodiment, each of the first tip portions 11 a and the second tip portions 12 a has a uniform dimension (thickness) in the up-down direction from the base to the tip, but the dimension in the left-right direction decreases from the base to the tip, resulting in a shape in which the cross-sectional area decreases from the base to the tip.

[0072] In the illustrated example, the first tip portions 11a have the same shape as one another when viewed from the top-bottom direction, and the second tip portions 12a have the same shape as one another when viewed from the top-bottom direction, but this is not limited to this. For example, the first tip portions 11a may have different shapes as viewed from the top-bottom direction, and the second tip portions 12a may have different shapes as viewed from the top-bottom direction. For example, the shapes of the first tip portions 11a and the second tip portions 12a can be changed according to design specifications.

[0073] In the protective element of the present embodiment described above, the cross-sectional area of ​​each of the first tip portions 11a and the second tip portions 12a decreases from the base to the tip, and the tips are connected with solder. This reduces the overall resistance of the fuse element while allowing current to flow easily. Therefore, when an overcurrent is interrupted, current concentration at the tips of the first tip portions 11a and the second tip portions 12a, combined with the melting of the fusible conductor, allows the fuse element to be more effectively interrupted (melts the fusing portion). This effectively shortens the overcurrent interruption time.

[0074] (Fifth embodiment) A protective element according to a fifth embodiment of the present invention will be described with reference to Figures 9 and 10. The protective element of the fifth embodiment mainly differs from the fourth embodiment described above in terms of the configuration of the soluble conductor 513. In addition, in each figure of this embodiment, components similar to or substantially similar to those of the first to fourth embodiments may be denoted by the same symbols or names, and descriptions thereof may be omitted.

[0075] 9 and 10, the first conductor 411 has a plurality of first tip portions 11a. The second conductor 412 has a plurality of second tip portions 12a. The plurality of first tip portions 11a and the plurality of second tip portions 12a face each other and are connected to the soluble conductor 513 in a state of proximity or contact. The example shown in the figure shows an example of one unit constituting a protective element. The unit is formed by the first conductor 411 and the second conductor 412, whose first tip portion 11a and second tip portion 12a are connected to the soluble conductor 513.

[0076] In this embodiment, the soluble conductor 513 is a laminate including a high-melting-point metal layer and a low-melting-point metal layer. Hereinafter, the soluble conductor 513 is also referred to as the "laminated body 513." When viewed from the top and bottom, the laminate 513 has a long shape in the left-right direction so as to straddle each of the plurality of first tip portions 11 a and the plurality of second tip portions 12 a.

[0077] In the illustrated example, the laminate 513 is rectangular or plate-shaped, has a first low-melting-point metal layer 513b as an inner layer, a high-melting-point metal layer 513a as an outer layer, and the upper surface of the outer layer is connected to the first tip portions 11a and the second tip portions 12a via a second low-melting-point metal layer 513c (e.g., solder), but is not limited thereto. For example, the laminate 513 may have one or more low-melting-point metal layers and two or more high-melting-point metal layers, with the low-melting-point metal layers disposed between the high-melting-point metal layers. The laminate 513 may be formed, for example, by coating the periphery of the low-melting-point metal layer with a high-melting-point metal layer.

[0078] For example, the high-melting-point metal layer of the laminate 513 is made of Ag (silver) or Cu (copper), or a metal containing Ag or Cu as a main component. The high-melting-point metal layer of the laminate 513 may contain Ag or Cu, and may be Ag alone, Cu alone, an Ag alloy, or a Cu alloy. An Ag alloy is an alloy with the highest Ag content among the metals contained in the alloy, and a Cu alloy is an alloy with the highest Cu content among the metals contained in the alloy.

[0079] For example, the low-melting-point metal layer of the laminate 513 is made of Sn or a metal containing Sn as a main component. The low-melting-point metal layer of the laminate 513 only needs to contain Sn, and may be Sn alone or an Sn alloy. An Sn alloy is an alloy containing Sn as a main component. An Sn alloy is an alloy with the highest Sn content among all metals contained in alloys. Examples of Sn alloys include an Sn-Bi alloy, an In-Sn alloy, and an Sn-Ag-Cu alloy.

[0080] The laminate 513 may have a two-layer structure of a low-melting-point metal layer / a high-melting-point metal layer. Alternatively, the laminate 513 may have a multilayer structure of three or more layers, including two or more high-melting-point metal layers, one or more low-melting-point metal layers, and a low-melting-point metal layer disposed between the high-melting-point metal layers. The soluble conductor 513 may also be composed of a single layer of a low-melting-point metal layer containing Sn.

[0081] In the illustrated example, the laminate 513 is connected to the bottom surface of each of the plurality of first tip portions 11 a and the plurality of second tip portions 12 a, but this is not limiting. For example, the laminate 513 may be connected to the top surface of each of the plurality of first tip portions 11 a and the plurality of second tip portions 12 a. For example, the manner in which each of the plurality of first tip portions 11 a and the plurality of second tip portions 12 a is connected to the laminate 513 can be changed according to design specifications.

[0082] In the protective element of the present embodiment described above, each of the multiple first tip portions 11a and the multiple second tip portions 12a has a shape in which the cross-sectional area decreases from the base to the tip, and each tip is connected to the laminate 513, so that the resistance value of the fuse element as a whole can be reduced while making it easier for current to flow. Therefore, when an overcurrent is interrupted, the current concentration at each tip of the multiple first tip portions 11a and the multiple second tip portions 12a, combined with the melting phenomenon of the fusible conductor 513, allows the fuse element to be more effectively interrupted (melts the fusing portion). Therefore, the overcurrent interruption time can be more effectively shortened.

[0083] Sixth Embodiment A protection element according to a sixth embodiment of the present invention will be described with reference to Figures 11 and 12. The protection element of the sixth embodiment differs from the fifth embodiment described above mainly in the manner of electrical connection in the fuse element. In each drawing of this embodiment, components that are the same or substantially the same as those in the first to fifth embodiments may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0084] 11 and 12, the first conductor 411 and the second conductor 412, whose first tip 11a and second tip 12a are connected to the fusible conductor 513, form one unit (each of the multiple units 605A and 605B). The multiple units 605A and 605B are electrically connected in series.

[0085] In the illustrated example, the fuse element has two units 605A and 605B, which are electrically connected in series, but this is not limiting. For example, the fuse element may have three or more units 605A, 605B, etc., which are electrically connected in series. For example, the number of units 605A and 605B can be changed depending on the design specifications.

[0086] In the example shown in the figure, each of the multiple units 605A, 605B has a portion (root portion) that is approximately a rectangular plate-like shape whose left-right dimension is longer than its front-to-back dimension when viewed from the top-to-bottom direction, multiple tip portions (multiple first tip portions 11a and multiple second tip portions 12a) that taper from the root portion toward the tip, and a laminate 513 connected to the multiple first tip portions 11a and the multiple second tip portions 12a.

[0087] In the illustrated example, the multiple units 605A and 605B have the same shape when viewed from the top and bottom, but this is not limited to this. For example, the multiple units 605A and 605B may have different shapes when viewed from the top and bottom. For example, the shapes of the multiple units 605A and 605B can be changed according to design specifications.

[0088] In the protective element of the present embodiment described above, the multiple first tip portions 11a and the multiple second tip portions 12a in each of the multiple units 605A, 605B each have a shape in which the cross-sectional area decreases from the base to the tip, and the respective tips are connected to the laminate 513, so that the resistance value of the fuse element as a whole can be reduced while making it easier for current to flow. Therefore, the current concentration at the tips of the multiple first tip portions 11a and the multiple second tip portions 12a during overcurrent interruption, combined with the melting phenomenon of the fusible conductor 513, allows the fuse element to be more effectively interrupted (melts the fusing portion). Therefore, the overcurrent interruption time can be more effectively shortened.

[0089] (Seventh embodiment) A protection element according to the seventh embodiment of the present invention will be described with reference to Figures 13 and 14. The protection element of the seventh embodiment mainly differs from the sixth embodiment described above in terms of the aspect of the laminate 713 (fusible conductor). In each figure of this embodiment, components similar to or substantially similar to those of the first to sixth embodiments may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0090] 13 and 14, each of the multiple units 705A, 705B includes a portion (root portion) that is an approximately rectangular plate-like portion whose left-right dimension is longer than its front-to-rear dimension when viewed from the top-to-bottom direction, multiple tip portions (multiple first tip portions 11a and multiple second tip portions 12a) that taper from the root portion toward the tip, and a laminate 713 connected to the multiple first tip portions 11a and the multiple second tip portions 12a.

[0091] In the illustrated example, the stack 713 has a shape that is long in the left-right direction so as to span the entirety of each of the multiple first tip portions 11a and the multiple second tip portions 12a when viewed from the top-bottom direction. In the illustrated example, the stack 713 has a shape that is long in the front-to-back direction so as to span from the bases of the multiple first tip portions 11a to the bases of the multiple second tip portions 12a when viewed from the top-bottom direction, but this is not limited to this. For example, the stack 713 may have a shape that is long in the front-to-back direction so as to span from the middle of the multiple first tip portions 11a (between the tip and the base) to the middle of the multiple second tip portions 12a when viewed from the top-bottom direction. In the illustrated example, the stack 713 has a shape that is longer in the left-to-right direction than the base portion when viewed from the top-bottom direction, but this is not limited to this. For example, the stack 713 may have the same left-to-right dimension as the base portion when viewed from the top-bottom direction, or may have a shorter left-to-right dimension than the base portion when viewed from the top-bottom direction. For example, the shape of the laminate 713 can be changed depending on the design specifications.

[0092] In the illustrated example, the laminate 713 is rectangular or plate-shaped, has a first low-melting-point metal layer 713b as an inner layer, a high-melting-point metal layer 713a as an outer layer, and the upper surface of the outer layer is connected to the first tip portions 11a and the second tip portions 12a via a second low-melting-point metal layer 713c (e.g., solder). However, this is not limited thereto. For example, the laminate 713 may have one or more low-melting-point metal layers and two or more high-melting-point metal layers, with the low-melting-point metal layers disposed between the high-melting-point metal layers. The laminate 713 may be formed, for example, by coating the low-melting-point metal layers with a high-melting-point metal layer. For example, the configuration of the laminate 713 can be changed according to design specifications.

[0093] In the protective element of the present embodiment described above, the cross-sectional area of ​​each of the first tip portions 11a and the second tip portions 12a in each of the multiple units 705A and 705B decreases from the base to the tip, and the entire tips are connected to the laminate 713. This reduces the resistance of the fuse element as a whole while allowing current to flow easily. Therefore, the current concentration at the tips of the first tip portions 11a and the second tip portions 12a during overcurrent interruption, combined with the melting phenomenon of the fusible conductor 713, allows the fuse element to be more effectively interrupted (melts the fusing portion). Therefore, the overcurrent interruption time can be more effectively shortened.

[0094] Eighth Embodiment A protection element according to an eighth embodiment of the present invention will be described with reference to Figs. 15 to 17. The protection element of the eighth embodiment differs from the sixth embodiment described above mainly in the configuration of the protection element. In each drawing of this embodiment, components that are the same or substantially the same as those in the first to seventh embodiments may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0095] 15 to 17 , the protection element further includes a first terminal 30 and a second terminal 40. A portion of the first conductor 411 is electrically connected to the first terminal 30. A portion of the second conductor 412 is electrically connected to the second terminal 40.

[0096] The first terminal 30 and the second terminal 40 are connected to both ends of the fuse elements 810, 820 in the current-carrying direction. In the example shown in the figure, each of the first terminal 30 and the second terminal 40 has a plate shape that extends in a plane direction (XY plane direction) perpendicular to the up-down direction. Each of the first terminal 30 and the second terminal 40 has a substantially rectangular plate shape. The first terminal 30 and the second terminal 40 are arranged spaced apart from each other in the front-to-rear direction.

[0097] The first terminal 30 is connected to the front ends of the fuse elements 810 and 820. The front portion of the first terminal 30 protrudes forward from the case 50 and is exposed to the outside of the case 50. The second terminal 40 is connected to the rear end of the fuse element. The rear portion of the second terminal 40 protrudes rearward from the case 50 and is exposed to the outside of the case 50.

[0098] An external terminal hole 31 is formed in the first terminal 30. The external terminal hole 31 is a circular hole that passes through the first terminal 30 in the vertical direction. The portion of the first terminal 30 that is rearward of the external terminal hole 31 is disposed between the terminal mounting surface 51 and the terminal pressing surface 52 in the front part of the case 50, and is sandwiched between the terminal mounting surface 51 and the terminal pressing surface 52.

[0099] An external terminal hole 41 is formed in the second terminal 40. The external terminal hole 41 is a circular hole that passes through the second terminal 40 in the vertical direction. The portion of the second terminal 40 that is forward of the external terminal hole 41 is disposed between the terminal mounting surface 51 and the terminal pressing surface 52 at the rear of the case 50, and is sandwiched between the terminal mounting surface 51 and the terminal pressing surface 52.

[0100] For example, one of the pair of external terminal holes 31, 41 is connected to the power supply side, and the other is connected to the load side. Note that, without being limited to the above, the external terminal holes 31, 41 may be connected to a current path inside the load. For example, the connection mode of the external terminal holes 31, 41 can be changed according to design specifications.

[0101] For example, each of the first terminal 30 and the second terminal 40 is made of a metal such as copper, brass, or nickel. Brass is preferred as the material for the first terminal 30 and the second terminal 40 from the viewpoint of increasing rigidity, and copper is preferred from the viewpoint of reducing electrical resistance. When copper is used, it is preferred to subject the surface to an anti-rust treatment such as nickel plating, silver plating, or tin plating. The first terminal 30 and the second terminal 40 may be made of the same material or different materials. For example, the material of each of the first terminal 30 and the second terminal 40 can be changed according to design specifications.

[0102] The first conductor 411 and the second conductor 412, whose first tip 11a and second tip 12a are connected to the fusible conductor 513, form one unit (each of the multiple units 805A, 805B, and 805C). The multiple units 805A, 805B, and 805C are electrically connected in parallel.

[0103] Furthermore, the multiple units 805A, 805B, and 805C are electrically connected in series. In the illustrated example, the fuse elements 810 and 820 each include three units 805A, 805B, and 805C, which are electrically connected in series, but this is not limiting. For example, the fuse elements 810 and 820 may include two or four or more units 805A, 805B, 805C, etc., which are electrically connected in series. For example, the number of units 805A, 805B, and 805C can be changed depending on the design specifications.

[0104] In the example shown in the figure, each of the multiple units 805A, 805B, and 805C includes a portion (root portion) that is approximately a rectangular plate-shaped portion whose left-right dimension is longer than its front-to-back dimension when viewed from the top-to-bottom direction, multiple tip portions (multiple first tip portions 11a and multiple second tip portions 12b) that taper from the root portion toward the tip, and a laminate 513 connected to the multiple first tip portions and the multiple second tip portions.

[0105] In the illustrated example, the multiple units 805A, 805B, and 805C have the same shape when viewed from the top to bottom, but this is not limited to this. For example, the multiple units 805A, 805B, and 805C may have different shapes when viewed from the top to bottom. For example, the shapes of the multiple units 805A, 805B, and 805C can be changed according to design specifications.

[0106] In the illustrated example, multiple units 805A, 805B, and 805C (hereinafter also referred to as "assemblies 806A and 806B") that are electrically connected in series are electrically connected in parallel. The assemblies 806A and 806B constitute fuse elements 810 and 820. The fuse elements 810 and 820 are constituted by metal plate-shaped members, sheet-shaped members, metal foils, or the like. In the illustrated example, two fuse elements 810 and 820 are provided. The two fuse elements 810 and 820 are arranged in parallel with each other. The two fuse elements 810 and 820 are arranged spaced apart from each other in the vertical direction.

[0107] Of the two fuse elements 810, 820, the one arranged below the first terminal 30 and the second terminal 40 is also referred to as the "first fuse element 810," and the one arranged above the first terminal 30 and the second terminal 40 is also referred to as the "second fuse element 820." The first fuse element 810 is arranged below the first terminal 30 and the second terminal 40 and spans between them. The second fuse element 820 is arranged above the first terminal 30 and the second terminal 40 and spans between them.

[0108] In the illustrated example, only one first fuse element 810 and one second fuse element 820 are provided, but this is not limited to this. For example, two fuse elements 810, 820 may be provided side by side in the vertical direction, or three or more fuse elements 810, 820 may be provided side by side. For example, the installation mode of each fuse element 810, 820 can be changed depending on the design specifications.

[0109] In the example shown in the figure, a portion of the first fuse element 810 that protrudes forward from the case 50 is connected to the underside of the first terminal 30 by press welding or the like. A portion of the second fuse element 820 that protrudes forward from the case 50 is connected to the upper surface of the first terminal 30 by press welding or the like. A portion of the first fuse element 810 that protrudes rearward from the case 50 is connected to the underside of the second terminal 40 by press welding or the like. A portion of the second fuse element 820 that protrudes rearward from the case 50 is connected to the upper surface of the second terminal 40 by press welding or the like.

[0110] The connection between the terminals 30, 40 and the fuse elements 810, 820 is not limited to the above. For example, the front portion of the first fuse element 810 may be connected to the lower surface of the first terminal 30 by soldering or the like. For example, the front portion of the second fuse element 820 may be connected to the upper surface of the first terminal 30 by soldering or the like. For example, the rear portion of the first fuse element 810 may be connected to the lower surface of the second terminal 40 by soldering or the like. For example, the rear portion of the second fuse element 820 may be connected to the upper surface of the second terminal 40 by soldering or the like. For example, the connection between the terminals 30, 40 and the fuse elements 810, 820 can be changed according to design specifications.

[0111] The protective element further includes a case 50. The case 50 contains a portion of the first terminal 30 and the second terminal 40, and two fuse elements 810, 820 (an example of one or more units). The case 50 is tubular and extends in the front-to-rear direction. A filler 70 is filled in at least a portion of the gap within the case 50.

[0112] The filler 70 has a function of filtering and cooling metal gas generated by arc discharge that occurs, for example, in a part of a circuit to be interrupted when an excessive current is flowing, thereby quickly and safely extinguishing the arc discharge. The filler 70 includes an arc-extinguishing agent, silica sand, inorganic fiber material, ceramic fiber, or silicone resin. For example, the filler 70 may further include one or more materials selected from the group consisting of an arc-extinguishing agent, silica sand, inorganic fiber material, ceramic fiber, or silicone resin, and / or a mixture thereof, and preferably includes silica sand or inorganic fiber material.

[0113] Silica sand is granular SiO ２ Silica sand is a type of sand that is primarily composed of quartz grains. Specifically, silica sand is a white, coarse-grained sand that contains a large amount of quartz grains among sandy deposits and weathering products whose main components are silicates.

[0114] For example, the inorganic fiber material may be a fiber material such as insulating fiber. ２ MgO, Al ２ O ３ , ZrO ２ Examples of suitable fiber materials include ceramic materials such as nylon and PMMA, and plastic materials such as nylon and PMMA. The type of fiber material is not limited to the above and can be changed depending on the design specifications.

[0115] For example, ceramic fiber paper can be used as the ceramic fiber. Although not shown, a plurality of ceramic fiber papers may be stacked and disposed in the gap inside the case 50.

[0116] Silicone resin, also known as silicon resin, generally refers to a polymer obtained by hydrolyzing a silane compound and having an organic substituent group that has been made high molecular weight through siloxane bonds, and is also called a hybrid polymer that combines inorganic and organic elements.

[0117] The filler 70 is not limited to the above, and various other materials can be used. For example, the filler 70 may be a spherical member (e.g., ceramic beads or ceramic balls) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the filler 70 may be a porous member (e.g., porous ceramic) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the filler 70 may be a spherical member (e.g., plastic beads or plastic balls) made of a plastic material such as nylon or PMMA (acrylic resin). For example, the filler 70 may be a porous member (e.g., porous plastic) made of a plastic material such as nylon or PMMA. For example, the filler 70 may be a sheet-like member, or may be in the shape of wool, a board, a block, or the like. For example, the filler 70 may be a plate-like member (e.g., plate-like ceramic) made of a ceramic material such as quartz glass, alumina, or zirconia. For example, the filler 70 may be silicone. Silicone is an inorganic polymer having a main chain of siloxane bonds in which silicon (Si) and oxygen (O) are repeatedly arranged. For example, the form of the filler 70 can be changed according to design specifications.

[0118] In the illustrated example, the filler 70 fills gaps within the case 50. A portion of the filler 70 contacts portions of the first fuse element 810 and the second fuse element 820. For example, first, portions of the first terminal 30 and the second terminal 40 and portions of the first fuse element 810 and the second fuse element 820 are sandwiched within the case 50. Thereafter, the filler 70 is introduced into the case 50 through a through-hole (not shown) formed in the case 50, thereby allowing the filler 70 to fill gaps within the case 50.

[0119] The filler 70 does not necessarily have to be completely filled into the case 50 without leaving any gaps, but may be filled with some gaps in the case 50. For example, the filler 70 may be sealed in at least some of the gaps in the case 50.

[0120] The case 50 is in close proximity to or in contact with both surfaces of the two fuse elements 810, 820 (examples of one or more units). In the example shown in the figure, the case 50 has a terminal mounting surface 51 and a terminal pressing surface 52 formed on both front and rear ends thereof, which contact the bottom surface of the first fuse element 810 and the top surface of the second fuse element 820, respectively.

[0121] The case 50 includes a plurality of holding members 50A, 50B. In the illustrated example, two of the plurality of holding members 50A, 50B are provided. The two holding members 50A, 50B are arranged adjacent to each other in the vertical direction. Of the two holding members 50A, 50B, the one arranged on the lower side is also referred to as the "first holding member 50A," and the one arranged on the upper side is also referred to as the "second holding member 50B."

[0122] The first holding member 50A is disposed below the first terminal 30, the second terminal 40, and the first fuse element 810. The first holding member 50A includes a terminal mounting surface 51. The terminal mounting surface 51 is recessed downward from the top surface of the first holding member 50A. The bottom surface of the terminal mounting surface 51 is flat and faces upward, and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. A pair of terminal mounting surfaces 51 are provided on the first holding member 50A. The pair of terminal mounting surfaces 51 are disposed at both ends of the first holding member 50A in the front-to-rear direction.

[0123] The second holding member 50B is disposed above the first terminal 30, the second terminal 40, and the second fuse element 820. The second holding member 50B includes a terminal pressing surface 52. The terminal pressing surface 52 is concave and recessed upward from the lower surface of the second holding member 50B. The bottom surface of the terminal pressing surface 52 is flat and faces downward, and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. A pair of terminal pressing surfaces 52 are provided on the second holding member 50B. The pair of terminal pressing surfaces 52 are disposed at both ends of the second holding member 50B in the front-to-rear direction. Note that the terminal pressing surface 52 may be formed on the side of the first holding member 50A facing the first terminal 30 and the second terminal 40.

[0124] When the first holding member 50A and the second holding member 50B are combined, an accommodation space 55 is formed between the first holding member 50A and the second holding member 50B. The first fuse element 810 and a portion of the second fuse element 820 are accommodated in the accommodation space 55. In the accommodation space 55, a filler 70 is filled in any gaps other than the portions where the first fuse element 810 and the second fuse element 820 are accommodated.

[0125] The protective element further includes an outer shell member 60 that covers the outside of the case 50 and secures the multiple holding members. The outer shell member 60 is cylindrical and extends in the front-to-rear direction. In the example shown in the figure, the outer shell member 60 is cylindrical and opens in the front-to-rear direction. The two holding members 50A, 50B are housed inside the outer shell member 60 in a combined state lined up in the vertical direction. The outer shell member 60 holds the two holding members 50A, 50B in a secured state by adhesive or the like.

[0126] For example, the outer shell member 60 and each of the holding members 50A and 50B are preferably formed from a material having a tracking resistance index (CTI) (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more. The tracking resistance index (CTI) can be determined by a test based on IEC 60112.

[0127] Resin materials can be used as the material for the outer shell member 60 and the holding members 50A, 50B. Resin materials have smaller heat capacities and lower melting points than ceramic materials. For this reason, using resin materials for the holding members 50A, 50B is preferable because it weakens arc discharge caused by gasification cooling (ablation) and, when molten and scattered metal particles adhere to the holding members 50A, 50B, the surfaces of the holding members 50A, 50B deform or the adhesions aggregate, making the metal particles sparse and making it difficult to form a conduction path.

[0128] Examples of resin materials that can be used include polyamide-based resins and fluororesins. In this embodiment, the case 50 is made of polyamide-based resins or fluororesins. The polyamide-based resins may be aliphatic polyamides or semi-aromatic polyamides. Examples of aliphatic polyamides include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of semi-aromatic polyamides include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. Examples of fluororesins include polytetrafluoroethylene. Furthermore, polyamide-based resins and fluororesins are highly heat-resistant and flammable. In particular, aliphatic polyamides are less likely to produce graphite when burned. Therefore, forming the outer shell member 60 and each of the holding members 50A and 50B using aliphatic polyamides more reliably prevents the formation of new current paths due to graphite generated by arc discharge when each fuse element melts.

[0129] In the protective element of the present embodiment described above, the multiple first tip portions 11a and the multiple second tip portions 12a in each of the multiple units 805A, 805B, and 805C each have a shape in which the cross-sectional area decreases from the base to the tip, and the respective tips are connected to the laminate 513. This reduces the resistance of the fuse elements 810 and 820 as a whole while allowing current to flow more easily. Therefore, the current concentration at the tips of the multiple first tip portions 11a and the multiple second tip portions 12a during overcurrent interruption, combined with the melting phenomenon of the fusible conductor 513, allows the fuse elements 810 and 820 to be more effectively interrupted (melt the fusing portion). Therefore, the overcurrent interruption time can be more effectively shortened.

[0130] In this embodiment, the protective element further includes a case 50. The case 50 contains a portion of the first terminal 30 and the second terminal 40, and two fuse elements 810, 820. A filler 70 is sealed in at least a portion of the gap within the case 50. With this configuration, each fuse element 810, 820 is surrounded by the filler 70, which makes it possible to eliminate as much gas as possible from around each fuse element 810, 820, which is one of the sources of arc discharge that occurs when an overcurrent is interrupted. This suppresses plasma that is generated by ionization of the gas, which is one of the sources of arc discharge, and thereby suppresses arc discharge.

[0131] In this embodiment, case 50 includes multiple holding members 50A, 50B. The protective element further includes an outer shell member 60 that covers the outside of case 50 and secures multiple holding members 50A, 50B. With this configuration, outer shell member 60 can suppress pressure (external force) acting on case 50 when an overcurrent is interrupted.

[0132] Ninth Embodiment A protection element according to a ninth embodiment of the present invention will be described with reference to Figs. 18 to 20. The protection element of the ninth embodiment differs from the eighth embodiment described above mainly in the configuration of the protection element. In each drawing of this embodiment, components that are the same or substantially the same as those in the first to eighth embodiments may be denoted by the same reference numerals or names, and descriptions thereof may be omitted.

[0133] 18 to 20, the protective element further includes a case 950 and two insulating members 90A, 90B (an example of one or more insulating members). The first conductor 411 and the second conductor 412, whose first and second tip portions 11a and 12a are connected to the fusible conductor 513, form a unit (each of the multiple units 805A, 805B, and 805C). The two insulating members 90A, 90B are in proximity to or in contact with both surfaces of a fuse element 820 (an example of one or more units). The case 950 contains a portion of the first terminal 30 and the second terminal 40, one fuse element 820, and two insulating members 90A, 90B. An internal pressure buffer space 95 is formed between the case 950 and the insulating members 90A, 90B. The insulating members 90A, 90B (an example of an insulating member and / or case) have a flow path 97 formed therein for releasing high-temperature gas generated between the internal pressure buffer space 95 and the fuse element 820 when the fuse element 820 is cut off.

[0134] The case 950 is in proximity to or in contact with the fuse element 820. In the example shown in the figure, the case 950 is in contact with the upper surface of the fuse element 820 at parts of terminal clamping surfaces 951, 952 (including a terminal placement surface and a terminal pressing surface) formed on both front and rear ends thereof.

[0135] The case 950 includes a plurality of holding members 950A, 950B. In the example shown in the figure, two of the plurality of holding members 950A, 950B are provided. The two holding members 950A, 950B are arranged adjacent to each other in the left-right direction. Of the two holding members 950A, 950B, the one arranged on the left side is also referred to as the "first holding member 950A," and the one arranged on the right side is also referred to as the "second holding member 950B."

[0136] The first holding member 950A is disposed to the left of the first terminal 30, the second terminal 40, and the fuse element 820. The first holding member 950A includes a terminal clamping surface 951. The terminal clamping surface 951 is concave and recessed from the right side surface of the first holding member 950A to the left. The upper and lower surfaces of the terminal clamping surface 951 are each flat and extend in a plane direction (XY plane direction) perpendicular to the up-down direction. A pair of terminal clamping surfaces 951 are provided on the first holding member 950A. The pair of terminal clamping surfaces 951 are disposed at both ends of the first holding member 950A in the front-to-rear direction.

[0137] The second holding member 950B is disposed to the right of the first terminal 30, the second terminal 40, and the fuse element 820. The second holding member 950B includes a terminal clamping surface 952. The terminal clamping surface 952 is concave and recessed from the left side surface of the second holding member 950B to the right. The upper and lower surfaces of the terminal clamping surface 952 are each flat and extend in a plane direction perpendicular to the up-down direction (XY plane direction). A pair of terminal clamping surfaces 952 are provided on the second holding member 950B. The pair of terminal clamping surfaces 952 are disposed at both ends of the second holding member 950B in the front-to-rear direction.

[0138] The protective element further includes an outer shell member 60 that covers the outside of the case 950 and secures multiple holding members 950A, 950B. The outer shell member 60 is cylindrical and extends in the front-to-rear direction. In the example shown in the figure, the outer shell member 60 is cylindrical and opens in the front-to-rear direction. The two holding members 950A, 950B are housed inside the outer shell member 60 in a combined state lined up in the left-to-right direction. The outer shell member 60 holds the two holding members 950A, 950B in a secured state by adhesive or the like.

[0139] For example, the outer shell member 60 and each of the holding members 950A and 950B are preferably made of a material having a tracking resistance index (CTI) (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more. The tracking resistance index (CTI) can be determined by a test based on IEC 60112.

[0140] Resin materials can be used as the material for the outer shell member 60 and the holding members 950A, 950B. Resin materials have smaller heat capacities and lower melting points than ceramic materials. For this reason, using resin materials for the holding members 950A, 950B is preferable because it weakens arc discharge caused by gasification cooling (ablation) and, when molten and scattered metal particles adhere to the holding members 950A, 950B, the surfaces of the holding members 950A, 950B deform or the adhesions aggregate, making the metal particles sparse and making it difficult to form a conduction path.

[0141] For example, the insulating members 90A, 90B are made of a nylon resin or a fluorine resin. For example, the insulating members 90A, 90B are preferably made of a resin having a tracking resistance index (CTI) of 500 V or more. The resin material constituting the insulating members 90A, 90B may be the same as that of the case 950 (outer shell member 60 and each holding member 950A, 950B) described above.

[0142] Each of the two insulating members 90A, 90B is plate-shaped, with a pair of plate surfaces facing the vertical direction. When viewed from the vertical direction, each of the two insulating members 90A, 90B has a rectangular plate shape whose left-right dimension is smaller than its front-to-back dimension. Of the two insulating members 90A, 90B, the one positioned on the lower side is also referred to as the "first insulating member 90A," and the one positioned on the upper side is also referred to as the "second insulating member 90B."

[0143] The first insulating member 90A is disposed below the first terminal 30, the second terminal 40, and the fuse element 820. The upper surface of the first insulating member 90A is in close proximity to or in contact with the lower surface of the fuse element 820.

[0144] The first insulating member 90A has a terminal support surface 91. The terminal support surface 91 is concave and recessed downward from the top surface of the first insulating member 90A. The bottom surface of the terminal support surface 91 is flat and faces upward, and extends in a plane direction (XY plane direction) perpendicular to the up-down direction. A pair of terminal support surfaces 91 are provided on the first insulating member 90A. The pair of terminal support surfaces 91 are located at both ends of the first insulating member 90A in the front-to-rear direction.

[0145] The first insulating member 90A has a flow path 97 (e.g., a leak hole and / or a gap) that opens in the vertical direction and extends in the horizontal direction, formed outside the fusible conductor 513 in the front-to-rear direction. The flow path 97 extends in a direction perpendicular to the current flow direction (approximately the front-to-rear direction) in which current flows through the fuse element 820. When the flow path 97 is formed in the first insulating member 90A, molten spatter that adheres to the upper surface of the first insulating member 90A after the fuse element 820 is interrupted becomes discontinuous at the flow path 97, and the insulation resistance between the first terminal 30 and the second terminal 40 after the interruption can be suitably increased.

[0146] The second insulating member 90B is disposed above the first terminal 30, the second terminal 40, and the fuse element 820. The lower surface of the second insulating member 90B is in close proximity to or in contact with the upper surface of the fuse element 820.

[0147] The second insulating member 90B has a flow path 97 (e.g., a leak hole and / or a gap) that opens in the vertical direction and extends in the horizontal direction, formed outside the front-to-rear direction of the fusible conductor 513. The flow path 97 extends in a direction perpendicular to the current flow direction (approximately the front-to-rear direction) in which current flows through the fuse element 820. When the flow path 97 is formed in the second insulating member 90B, molten spatter that adheres to the underside of the second insulating member 90B after the fuse element 820 is interrupted becomes discontinuous at the flow path 97, and the insulation resistance between the first terminal 30 and the second terminal 40 after the interruption can be suitably increased.

[0148] In the illustrated example, two leak holes serving as flow paths 97 are arranged spaced apart in the front-to-rear direction. The leak holes extend linearly in the up-down direction. For example, the opening area of ​​the leak holes (the cross-sectional area when the leak holes are cut along a plane perpendicular to the up-down direction) is 20% or less of the length in the current-carrying direction of the area where the insulating members 90A, 90B and the fuse element 820 are adjacent to or in contact with each other, in the area where the insulating members 90A, 90B and the fuse element 820 are adjacent to or in contact with each other. However, there is no restriction on the opening area outside the area where the insulating members 90A, 90B and the fuse element 820 are adjacent to or in contact with each other. Note that the configuration of the leak holes (number, location, shape, opening area, etc.) is not limited to the above and can be changed according to design specifications.

[0149] When the above-described members 90A, 90B, 950A, and 950B are combined, an element accommodating space 96 is formed between the first insulating member 90A and the second insulating member 90B. The element accommodating space 96 accommodates a fuse element 820.

[0150] A portion of the upper surface of the first insulating member 90A (a portion of the surface facing the element accommodating space 96) is configured to be in close proximity to or in contact with the lower surface of the fuse element 820. A portion of the lower surface of the second insulating member 90B (a portion of the surface facing the element accommodating space 96) is configured to be in close proximity to or in contact with the upper surface of the fuse element 820.

[0151] When the first holding member 950A and the second holding member 950B are combined, an internal pressure buffering space 95 is formed between the first holding member 950A and the second holding member 950B. The internal pressure buffering space 95 communicates with the element accommodating space 96 via a flow path 97. The internal pressure buffering space 95 has the effect of suppressing a sudden increase in the internal pressure of the protective element caused by gas generated by arc discharge that occurs when the fuse element 820 melts.

[0152] A filler 70 is enclosed in the internal pressure buffering space 95. The filler 70 includes an arc-extinguishing agent, silica sand, an inorganic fiber material, a ceramic fiber, or a silicone resin. For example, the filler 70 may further include one or more materials selected from the group consisting of an arc-extinguishing agent, silica sand, an inorganic fiber material, a ceramic fiber, a silicone resin, and / or a mixture thereof, and preferably includes silica sand or an inorganic fiber material.

[0153] In the illustrated example, the filler 70 fills the internal pressure buffer space 95 inside the protection element. A portion of the filler 70 contacts the lower surface of the first insulating member 90A located below the fuse element 820. A portion of the filler 70 contacts the upper surface of the second insulating member 90B located above the fuse element 820.

[0154] For example, first, a portion of the first terminal 30 and the second terminal 40 and a portion of the fuse element 820 are sandwiched within the case 950. Thereafter, the filler 70 is introduced into the case 950 (internal pressure buffering space 95) through a through-hole (not shown) formed in the case 950, thereby filling the internal pressure buffering space 95 with the filler 70.

[0155] The filler 70 does not necessarily have to be completely filled into the internal pressure buffering space 95 without leaving any gaps, but may be filled with gaps in part of the internal pressure buffering space 95. For example, the filler 70 may be disposed in at least a part of the internal pressure buffering space 95.

[0156] The orientation of the protective element does not necessarily have to be such that its up-down direction is aligned with the direction of gravity, but may be such that it intersects with the direction of gravity. For example, if the filler 70 is filled without gaps in the internal pressure buffering space 95, the protective element may be disposed at an angle with respect to the direction of gravity. For example, the arrangement of the protective element can be changed according to design specifications.

[0157] In the protective element of the present embodiment described above, the multiple first tip portions 11a and the multiple second tip portions 12a in each of the multiple units 805A, 805B, and 805C each have a shape in which the cross-sectional area decreases from the base to the tip, and the respective tips are connected to the laminate 513. This reduces the resistance of the fuse element 820 as a whole while allowing current to flow easily. Therefore, the current concentration at the tips of the multiple first tip portions 11a and the multiple second tip portions 12a during overcurrent interruption, combined with the melting phenomenon of the fusible conductor 513, allows the fuse element 820 to be more effectively interrupted (melts the fusing portion). Therefore, the overcurrent interruption time can be more effectively shortened.

[0158] In this embodiment, the protective element further includes a case 950 and two insulating members 90A and 90B. The two insulating members 90A and 90B are in close proximity to or in contact with both surfaces of one fuse element 820. The case 950 contains a portion of the first terminal 30 and the second terminal 40, one fuse element 820, and two insulating members 90A and 90B. An internal pressure buffering space 95 is formed between the case 950 and the insulating members 90A and 90B. The insulating members 90A and 90B have flow paths 97 for releasing high-temperature gas generated between the internal pressure buffering space 95 and the fuse element 820 when the fuse element 820 is interrupted. This configuration narrows the space formed between the fuse element 820 and the insulating members 90A and 90B, thereby minimizing gas, which is one of the sources of arc discharge that occurs when an overcurrent is interrupted, around the fuse element 820. This suppresses the generation of plasma due to the ionization of gas, which is one of the sources of arc discharge, thereby suppressing arc discharge. Additionally, there is no need to fill the fuse element 820 with silica sand, known as an arc-extinguishing agent, to suppress arc discharge. This eliminates problems (such as reduced interruption characteristics and reduced insulation resistance after interruption) caused by continuous adhesion of molten debris to the surface of the arc-extinguishing agent. This suppresses arc discharge during interruption, enables high-voltage and high-current interruption, and prevents a decrease in insulation resistance after interruption. Additionally, gasified metal gas from the fuse element 820 can escape through the flow paths 97 formed in the insulating members 90A and 90B.

[0159] In this embodiment, the insulating members 90A, 90B are made of nylon-based resin or fluororesin. According to this configuration, nylon-based resin and fluororesin have high heat resistance and are resistant to combustion. Among nylon-based resins, aliphatic polyamides, in particular, are less likely to produce graphite even when burned. Therefore, by forming the insulating members 90A, 90B from aliphatic polyamide, graphite production due to arc discharge when the fuse element 820 melts can be suppressed, and the formation of new current paths can be more reliably prevented. Furthermore, because carbon black used for coloring also leads to graphite production, a material that does not contain carbon black (e.g., a natural-colored resin material) is more preferable.

[0160] In this embodiment, the filler 70 is sealed in the internal pressure buffering space 95. With this configuration, the insulating members 90A and 90B suppress the occurrence of arc discharge, while the filler 70 sufficiently suppresses a sudden increase in the internal pressure of the protective element caused by molten debris entering the internal pressure buffering space 95. Therefore, it is possible to suppress the occurrence of a large-scale arc discharge when the fuse element 820 melts.

[0161] In this embodiment, the filler 70 includes an arc-extinguishing agent, silica sand, inorganic fiber material, ceramic fiber, or silicone resin. When the filler 70 includes at least silica sand, the surface area of ​​each silica sand particle can be ensured, making it easier to increase the surface area of ​​the filler 70 as a whole compared to when the filler 70 is plate-shaped. Therefore, it is easier to prevent a sudden increase in the internal pressure of the protective element due to molten debris entering the internal pressure buffering space 95. When the filler 70 includes at least inorganic fiber material, the surface area of ​​the filler 70 can be ensured, making it easier to increase the surface area of ​​the filler 70 as a whole compared to when the filler 70 is plate-shaped. Additionally, when the filler 70 includes at least inorganic fiber material, there are more elements to capture molten debris compared to when the filler 70 is plate-shaped. Therefore, it is easier to prevent a sudden increase in the internal pressure of the protective element due to molten debris entering the internal pressure buffering space 95.

[0162] In this embodiment, case 950 includes a plurality of holding members 950A, 950B. The protective element further includes an outer shell member 60 that covers the outside of case 950 and secures the plurality of holding members 950A, 950B. With this configuration, outer shell member 60 can suppress pressure (external force) acting on case 950 when an overcurrent is interrupted.

[0163] The present invention may be combined with the various configurations described in the above-described embodiments and modifications, and may also include additions, omissions, substitutions, and other modifications of the configurations, without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the above-described embodiments, but is limited only by the claims.

[0164] DESCRIPTION OF SYMBOLS 1 Unit 11 First conductor 11a First tip 12 Second conductor 12a Second tip 13 Fusible conductor 30 First terminal 40 Second terminal 50 Case 50A First holding member (holding member) 50B Second holding member (holding member) 60 Outer shell member 70 Filler 90A First insulating member (insulating member) 90B Second insulating member (insulating member) 95 Internal pressure buffer space 97 Flow path 211 First conductor 212 Second conductor 211a First tip 212a Second tip 312 Second conductor 312a Second tip 411 First conductor 412 Second conductor 513 Fusible conductor (laminated body) 513a High melting point metal layer 513b First low melting point metal layer (low melting point metal layer) 513c Second low melting point metal layer (low melting point metal layer) 605A, 605B Unit 705A, 705B Unit 713 Fusible conductor (laminated body) 805A, 805B, 805C Unit 950 Case 950A First holding member (holding member) 950B Second holding member (holding member)

Claims

1. A protective element comprising: a first conductor having at least one first tip; and a second conductor, wherein the first tip has a shape in which a cross-sectional area decreases from a base to a tip, and at least a portion of the first tip and the second conductor are connected to a fusible conductor having a melting temperature lower than each of the first conductor and the second conductor.

2. The protective element described in claim 1, wherein the second conductor has at least one second tip portion, the second tip portion has a shape in which the cross-sectional area decreases from the base to the tip, and at least a portion of the first tip portion and the second tip portion are connected to the fusible conductor.

3. The protection element according to claim 2, wherein the first tip portion and the second tip portion face each other and are in close proximity to or in contact with each other.

4. A protection element according to any one of claims 1 to 3, wherein each of the first conductor and the second conductor is a plate-shaped member made of metal.

5. A protective element according to any one of claims 1 to 3, wherein each of the first conductor and the second conductor is made of Ag or Cu, or a metal containing Ag or Cu as a main component.

6. The protective element according to any one of claims 1 to 3, wherein the fusible conductor is made of Sn or a metal mainly composed of Sn.

7. The protective element according to any one of claims 1 to 3, wherein the fusible conductor is a laminate including a high melting point metal layer and a low melting point metal layer.

8. The protective element according to claim 7, wherein the high melting point metal layer is made of Ag or Cu, or a metal mainly composed of Ag or Cu, and the low melting point metal layer is made of Sn or a metal mainly composed of Sn.

9. A protective element as described in claim 2 or 3, wherein the first conductor has a plurality of the first tips, the second conductor has a plurality of the second tips, and the plurality of the first tips and the plurality of the second tips face each other and are connected to the fusible conductor in a state of close proximity or contact.

10. A protection element as described in claim 2 or 3, further comprising a first terminal and a second terminal, a portion of the first conductor being electrically connected to the first terminal, and a portion of the second conductor being electrically connected to the second terminal.

11. The protective element described in claim 10, wherein the first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form a single unit, and a plurality of the units are electrically connected in series.

12. The protective element described in claim 10, wherein the first conductor and the second conductor, whose first tip and second tip are connected to the fusible conductor, form one unit, and a plurality of the units are electrically connected in parallel.

13. A protective element as described in claim 2, further comprising a case, wherein the first conductor and the second conductor, the first tip and the second tip of which are connected to the fusible conductor, form a single unit, the case enclosing a portion of the first terminal and the second terminal and one or more of the units, and at least a portion of the gap within the case being filled with a filler material.

14. The protective element according to claim 13, wherein the filler material includes an arc-extinguishing agent, silica sand, an inorganic fiber material, a ceramic fiber, or a silicone resin.

15. A protective element as described in claim 2, further comprising a case, wherein the first conductor and the second conductor, the first tip and the second tip of which are connected to the fusible conductor, form a single unit, each of the first conductor and the second conductor being a metal plate-like member, and the case encloses a portion of the first terminal and the second terminal and one or more of the units, and is in close proximity to or in contact with both sides of the one or more of the units.

16. A protective element as described in claim 2, further comprising a case and one or more insulating members, the first conductor and the second conductor, the first tip and the second tip of which are connected to the fusible conductor, forming a single unit, each of the first conductor and the second conductor being a metal plate-shaped member, the one or more insulating members being in close proximity to or in contact with both sides of the one or more units, the case containing a portion of the first terminal and the second terminal, the one or more units, and the one or more insulating members, an internal pressure buffering space being formed between the case and the insulating member, and a flow path being formed in the insulating member and / or the case for releasing high-temperature gas generated between the internal pressure buffering space and the unit when the unit is shut off.

17. The protection element according to claim 16, wherein the insulating member is made of a nylon resin or a fluorine resin.

18. The protection element according to claim 16, wherein a filler is filled in the internal pressure buffer space.

19. The protective element according to claim 18, wherein the filler material includes an arc-extinguishing agent, silica sand, an inorganic fiber material, a ceramic fiber, or a silicone resin.

20. A protective element as claimed in any one of claims 13, 15 and 16, wherein the case includes a plurality of holding members, and further comprises an outer shell member that covers the outside of the case and fixes the plurality of holding members.

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