Protection element

Abstract

To provide a protection element that can handle high-voltage and high-current interruption and reduces an overcurrent interruption time.SOLUTION: A protection 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 a cross section area decreases from a base to a tip. At least a part of the first tip 211a and the second conductor 312 is connected to a soluble conductor 13 having a melting temperature lower than that of each of the first conductor 211 and the second conductor 312.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

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

[0004] As a technique for forming a heat spot in a foil-shaped fuse element by using a hole, a change in thickness, a notch, etc., and melting the fuse element during overcurrent, there are the following. For example, Patent Document 1 discloses a fuse in which the thickness of a cut-off portion of a conductive thin film pattern formed on an insulating substrate is set thinner than the thickness of a connecting portion connected in series to the cut-off portion. For example, Patent Documents 2 and 3 disclose a fuse element in which a plurality of elements arranged in parallel are formed with holes by punching to form a melting portion. For example, Patent Documents 4 and 5 disclose a fuse in which, in a pattern of a conductive thin film formed on the surface of an insulating substrate, the thickness of a cut-off portion in which a plurality of cut-off portion sandwiching portions are arranged in parallel is thinner than the thickness of a connecting band connected in series to the cut-off portion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a protection element for dealing with high voltage and large current interruption, generally, a fuse element obtained by processing a part of an inexpensive metal foil with a low resistivity such as a copper foil into a punching metal shape is used. Although this fuse element has sufficient interruption performance in a large current region, in a relatively small current region (for example, about 2 to 3 times the rated current), the interruption time may be too long or it may not be interrupted.

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

Means for Solving the Problems

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

[0009] [Aspect 1] A protection element including 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 part of the first tip portion and the second conductor is connected to a soluble conductor having a melting temperature lower than that of each of the first conductor and the second conductor.

[0010] [Aspect 2] 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 part of the first tip portion and the second tip portion is connected to the soluble conductor. The protection element according to Aspect 1.

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

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

[0013] [Aspect 5] Each of the first conductor and the second conductor is made of Ag or Cu, or a metal mainly composed of Ag or Cu. The protection element according to any one of Aspects 1 to 4.

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

[0015] [Aspect 7] The soluble conductor is a laminate including a high melting point metal layer and a low melting point metal layer. The protection element according to any one of Aspects 1 to 5.

[0016] [Aspect 8] 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. The protection element according to Aspect 7.

[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 face each other and are connected to the soluble conductor in a state of being close to or in contact with each other. The protection element according to Aspect 2 or 3.

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

[0019] [Aspect 11] The first conductor and the second conductor, in which the first tip and the second tip are connected to the soluble conductor, form one unit, and a plurality of the units are electrically connected in series. The protection element according to aspect 10.

[0020] [Aspect 12] The first conductor and the second conductor, in which the first tip and the second tip are connected to the soluble conductor, form one unit, and a plurality of the units are electrically connected in parallel. The protection element according to aspect 10 or 11.

[0021] [Aspect 13] The protection element according to any one of aspects 2, 3, 9 to 12, further comprising a case, wherein the first conductor and the second conductor, in which the first tip and the second tip are connected to the soluble conductor, form one unit, the case encloses a part of the first terminal and the second terminal and one or more of the units, and a filling material is encapsulated in at least a part of the gap in the case.

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

[0023] [Aspect 15] The protection element according to any one of aspects 2, 3, 9 to 12, further comprising a case, wherein the first conductor and the second conductor, in which the first tip and the second tip are connected to the soluble conductor, form one unit, each of the first conductor and the second conductor is a plate-like member made of metal, the case encloses a part of the first terminal and the second terminal and one or more of the units, and is close to or in contact with both sides of one or more of the units.

[0024] [Aspect 16] Further comprising a case and one or more insulating members, the first conductor and the second conductor, wherein the first tip and the second tip are connected to the soluble conductor, form one unit, each of the first conductor and the second conductor is a plate-like member made of metal, one or more of the insulating members are close to or in contact with both surfaces of one or more of the units, the case encloses a part 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 buffer space is formed between the case and the insulating member, and a flow path is formed in the insulating member and / or the case for releasing high-temperature gas generated between the internal pressure buffer space and the unit when the unit is interrupted. The protection element according to any one of Aspects 2, 3, 9 to 12.

[0025] [Aspect 17] The protection 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 protection element according to Aspect 16 or 17, wherein a filling material is enclosed in the internal pressure buffer space.

[0027] [Aspect 19] The protection element according to Aspect 18, wherein the filling material includes an arc extinguishing agent, silica sand, an inorganic fiber material, ceramic fiber, or a silicone resin.

[0028] [Aspect 20] The protection element according to 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. [Advantages of the Invention]

[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. [Brief Description of the Drawings]

[0030]

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Embodiments for Carrying Out the Invention

[0031] Hereinafter, the embodiments will be described in detail with appropriate reference to the drawings. The drawings used in the following description may show, for the sake of clarity, parts that are characteristic in an enlarged manner, and the dimensional ratios of the respective components may be different from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and can be appropriately modified and implemented within the scope in which the effects of the present invention can be achieved.

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

[0033] As shown in FIG. 1, the protection 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 example of the figure, the protection element includes a first conductor 11 having only one first tip 11a and a second conductor 12 having only one second tip 12a, but is not limited thereto. For example, the protection element may include a first conductor 11 having two or more first tips 11a and a second conductor 12 having two or more second tips 12a. For example, the arrangement modes of the first tip 11a and the second tip 12a can be changed according to the design specifications. In the example of the figure, an example of one unit 1 constituting the protection element is shown. The unit 1 is formed by the first conductor 11 and the second conductor 12 in which the first tip 11a and the second tip 12a are connected to the soluble 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 part of the first tip 11a and the second tip 12a is connected to a soluble conductor 13 having a melting temperature lower than that of each of the first conductor 11 and the second conductor 12. In the example of 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. In the example of the figure, an example in which a part of the fuse element 10 is cut out is shown. As a mechanism for interrupting the current path, the protection element has an overcurrent interruption in which when an overcurrent (current equal to or greater than a predetermined value) exceeding the rated current flows through the fuse element 10, the fuse element 10 is blown to interrupt the current path.

[0036] Hereinafter, an XYZ orthogonal coordinate system (three-dimensional orthogonal coordinate system) may be set for each figure, and each configuration may be described. 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. Among the X-axis directions, the direction from the second tip portion 12a toward the first tip portion 11a (-X side) is referred to as the front side, and the direction from the first tip portion 11a toward 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, and since it is also the direction in which electricity flows when the protection element is in use, it may be rephrased as the energization direction.

[0037] The direction in which each plate surface of the first conductor 11 and the second conductor 12 faces is referred to as the up-down direction. The up-down direction is a direction orthogonal to the front-rear direction and corresponds to the Z-axis direction in each figure. Among the up-down directions, the upper side corresponds to the +Z side, and the lower side corresponds to the -Z side.

[0038] The direction orthogonal to the front-rear direction and the up-down direction is referred to as the left-right direction. The left-right direction corresponds to the Y-axis direction in each figure. Among the left-right directions, 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 protection element is viewed from the rear side (+X side), and the +Y side is the right side when the protection element is viewed from the rear side. Note that the left-right direction may be rephrased as the width direction. In this case, for example, one side of the width direction corresponds to the -Y side, and the other side of the width direction corresponds to the +Y side.

[0039] Note that in this embodiment, the front side, rear side, upper side, lower side, left side, and right side are convenient names for easily explaining the relative positional relationship of each component, and the actual arrangement relationship, etc. may be an arrangement relationship other than the arrangement relationship 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 energization direction (the direction of the arrow in the figure). The fusible conductor 13 is made of a material having a melting temperature lower than that of each of the first conductor 11 and the second conductor 12. Further, the fusible conductor 13 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 overcurrent is interrupted.

[0041] In the example of the figure, the first tip portion 11a and the second tip portion 12a face each other and are close to each other. Note that the first tip portion 11a and the second tip portion 12a may face each other and be in contact with each other. For example, the manner in which the first tip portion 11a and the second tip portion 12a are close to or in contact with each other can be changed according to the 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. Note that each of the first conductor 11 and the second conductor 12 may be in a sheet shape or a foil shape. In the example of the figure, each of the first conductor 11 and the second conductor 12 has a substantially rectangular plate-like portion (base portion) whose left-right dimension is shorter than the front-rear dimension when viewed from the up-down direction, and a tip portion (the first tip portion 11a and the second tip portion 12a) that tapers from the base portion toward the tip.

[0043] In the example of the figure, each of the first tip portion 11a and the second tip portion 12a has a shape in which the left-right dimension becomes shorter from the base to the tip when viewed from the up-down direction, and the outer edge portion in the left-right direction is curved inward. In the present embodiment, each of the first tip portion 11a and the second tip portion 12a has a uniform dimension (thickness) in the up-down direction from the base to the tip, but the left-right dimension becomes shorter from the base to the tip, so that the cross-sectional area decreases from the base to the tip. The cross-sectional area corresponds to the area when the tip portion is cut by a plane (YZ plane) orthogonal to the front-rear direction (energization 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 using copper, it is preferable to perform rust prevention treatment such as nickel plating, silver plating, or tin plating on the surface.

[0045] The first conductor 11, the soluble conductor 13, and the second conductor 12 are connected in series in this order to form an energization 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 soluble conductor 13 with the tips facing each other in the energization direction (corresponding to the substantially front-rear direction in the example of the figure) in which current flows through the fuse element 10.

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

[0047] In this embodiment, the soluble conductor 13 is made of Sn (tin) or a metal mainly composed of Sn. As the metal used for the soluble conductor 13, it is preferable to use solder such as lead-free solder mainly composed of Sn. Since the melting point of Sn is 217°C, the solder mainly composed of Sn has a lower melting point than copper foil (melting point 1084°C), and the soluble conductor 13 is likely to dissolve during overcurrent interruption. 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 metal plate (not shown) is cut to obtain a plate material having an outer dimension larger than the outer dimension of the entire plan view including the first conductor 11 and the second conductor 12. Note that the thickness of the cut metal plate may be adjusted by hammering or the like on the portions corresponding to the first conductor 11 and the second conductor 12.

[0049] Next, the first conductor 11 and the second conductor 12 are obtained by performing punching (press working) and / or cutting on the cut metal plate. Note that the cut metal plate may be positioned on an automatic positioning punching machine and punched with a punching machine having a cutting edge whose planar shape is the entire shape of the first conductor 11 and the second conductor 12 as a die.

[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 by solder. Thereby, the fuse element 10 of the present embodiment can be manufactured.

[0051] The protection element of the present embodiment described above includes a first conductor 11 having at least one first tip portion 11a and a second conductor 12 having at least one second tip portion 12a. Each of the first tip portion 11a and the second tip portion 12a has a shape in which the cross-sectional area decreases from the base to the tip. At least a part of the first tip portion 11a and the second tip portion 12a is connected to a soluble conductor 13 having a melting temperature lower than that of each of the first conductor 11 and the second conductor 12. According to this configuration, since each of the first tip portion 11a and the second tip portion 12a has a shape in which the cross-sectional area decreases from the base toward the tip, current concentrates at the tip of each of the first tip portion 11a and the second tip portion 12a when overcurrent is interrupted. In addition, since at least a part of the first tip portion 11a and the second tip portion 12a is connected to a soluble conductor 13 having a melting temperature lower than that of each of the first conductor 11 and the second conductor 12, the melting temperature of the fusing portion becomes lower than the melting point of each of the first conductor 11 and the second conductor 12, and the soluble conductor 13 is more likely to melt. Therefore, due to the combination of the current concentration at the tip of each of the first tip portion 11a and the second tip portion 12a at the time of overcurrent interruption and the melting phenomenon of the soluble conductor 13, interruption in a relatively small current region (for example, about 2 to 3 times the rated current) is possible and the interruption time can be shortened. Accordingly, it is possible to provide a protection element that can handle high voltage and large current interruption and can shorten the overcurrent interruption time.

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

[0053] In the present embodiment, each of the first conductor 11 and the second conductor 12 is a plate-shaped member made of metal. According to this configuration, by changing the plate thickness of each of the first conductor 11 and the second conductor 12, the cross-sectional area (the degree of current concentration at each tip) of each of the first tip portion 11a and the second tip portion 12a can be adjusted. In addition, each of the first tip portion 11a of the first conductor 11 and the second tip portion 12a of the second conductor 12 can be easily formed by punching (press working) 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 having Ag or Cu as a main component. According to this configuration, the electrical resistivity of each of the first conductor 11 and the second conductor 12 is likely to be smaller than that in the case where each of them is a laminate including a high melting point metal layer and a low melting point metal layer. Therefore, even when each of the first conductor 11 and the second conductor 12 made of a single layer containing Ag or Cu has the same area and equivalent electrical resistance as that made of a laminate including a high melting point metal layer and a low melting point metal layer, the thickness can be reduced. When the thickness of each of the first conductor 11 and the second conductor 12 is small, the amount of molten and scattered matter when the fuse element 10 is blown is also reduced in proportion to the thickness, and the insulation resistance after interruption becomes high.

[0055] In this embodiment, the fusible conductor 13 is made of Sn or a metal having Sn as a main component. According to this configuration, since the melting point of Sn is lower than that of Cu or the like, the fusible conductor 13 is likely to melt during overcurrent interruption. Therefore, the overcurrent interruption time can be more effectively shortened.

[0056] For example, if the cross-sectional area of each of the first tip portion and the second tip portion is constant from the base to the tip and only a part of each tip is connected by a fusible conductor, the resistance value becomes high and it is highly likely that the current does not easily flow. On the other hand, in this embodiment, since each of the first tip portion 11a and the second tip portion 12a has a shape in which the cross-sectional area decreases from the base to the tip and the tips of each are connected by solder, while suppressing the resistance value of the entire fuse element 10, the current can easily flow. Therefore, the current concentration at the tip of each of the first tip portion 11a and the second tip portion 12a and the melting phenomenon of the fusible conductor 13 during overcurrent interruption are combined to more effectively interrupt (blow the blown portion) the fuse element 10 (see FIG. 2). Therefore, the overcurrent interruption time can be more effectively shortened.

[0057] The present invention is not limited to the above-described embodiments. For example, as described below, modifications such as changes in configuration are possible without departing from the gist of the present invention. In the illustrations of other embodiments and variations, the same components as those in the above-described embodiments are denoted by the same reference numerals, and the following mainly describes the differences.

[0058] (Second Embodiment) The protective element according to the second embodiment of the present invention will be described with reference to FIGS. 3 to 4. The protective element of the second embodiment is mainly different from that of the first embodiment described above in the shapes of the first tip portion 211a and the second tip portion 212a. In each figure of the present embodiment, components that are the same as or substantially the same as those in the first embodiment may be denoted by the same reference numerals or the same names, and the description may be omitted.

[0059] As shown in FIG. 3, each of the first conductor 211 and the second conductor 212 has a substantially square plate-shaped portion (base portion) whose lateral dimension is shorter than its longitudinal dimension when viewed from the vertical direction, and a tip portion (the first tip portion 211a and the second tip portion 212a) that tapers from the base portion toward the tip. In the example of the figure, an example of one unit constituting the protective element is shown. The unit is formed by the first conductor 211 and the second conductor 212 to which the first tip portion 211a and the second tip portion 212a are connected to the soluble conductor 13.

[0060] In the example of the figure, each of the first tip portion 211a and the second tip portion 212a has a shape in which the lateral dimension becomes shorter from the base toward the tip when viewed from the vertical direction, and the outer edge portion in the lateral direction is linearly inclined toward the tip. In the example of the figure, each of the first tip portion 211a and the second tip portion 212a has a triangular shape protruding from the base toward the tip when viewed from the vertical direction. In the present embodiment, each of the first tip portion 211a and the second tip portion 212a has a uniform vertical dimension (thickness) from the base toward the tip, but the lateral dimension becomes shorter from the base toward the tip, so that the cross-sectional area decreases from the base toward the tip.

[0061] In the protection element of the present embodiment described above, since each of the first tip portion 211a and the second tip portion 212a has a shape in which the cross-sectional area decreases from the base toward the tip and the tips of each are connected by solder, the resistance value of the entire fuse element can be suppressed while making it easier for current to flow. Therefore, due to the combination of current concentration at the tip of each of the first tip portion 211a and the second tip portion 212a and the melting phenomenon of the fusible conductor during overcurrent interruption, the fuse element can be more effectively interrupted (the fusing portion is fused) (see FIG. 4). Therefore, the overcurrent interruption time can be more effectively shortened.

[0062] (Third Embodiment) The protection element according to the third embodiment of the present invention will be described with reference to FIGS. 5 to 6. The protection element of the third embodiment is mainly different in that the shapes of the first tip portion 211a and the second tip portion 312a are different from those of the first embodiment described above. In each figure of the present embodiment, components that are the same as or substantially the same as those of the first embodiment and the second embodiment may be omitted from the description by attaching the same reference numerals or the same names.

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

[0064] As shown in FIG. 5, the first conductor 211 includes a substantially rectangular plate-shaped portion (base portion) whose lateral dimension is shorter than its longitudinal dimension when viewed from the vertical direction, and a tip portion (first tip portion 211a) that tapers from the base portion toward the tip. The second conductor 312 is substantially rectangular plate-shaped with a lateral dimension shorter than its longitudinal dimension when viewed from the vertical direction.

[0065] In the example of the figure, the first tip portion 211a has a shape in which the lateral dimension becomes shorter from the base toward the tip when viewed from the vertical direction, and the outer edge portions in the lateral direction are linearly inclined toward the tip. In the example of the figure, the first tip portion 211a has a triangular shape that protrudes from the base toward the tip when viewed from the vertical direction. In the present embodiment, the first tip portion 211a has a uniform vertical dimension (thickness) from the base toward the tip, but the lateral dimension becomes shorter from the base toward the tip, resulting in a shape in which the cross-sectional area decreases from the base toward the tip. The second tip portion 312a has a uniform vertical dimension (thickness), the same lateral dimension in the front-rear direction, and a constant cross-sectional area in the front-rear direction.

[0066] In the protection element of the present embodiment described above, since the first tip portion 211a has a shape in which the cross-sectional area decreases from the base toward the tip and the tip of the first tip portion 211a is connected to the tip of the second conductor 312 by soldering, the resistance value of the entire fuse element can be suppressed while allowing current to flow easily. Therefore, due to the combination of current concentration at the tip of the first tip portion 211a and the melting phenomenon of the fusible conductor during overcurrent interruption, the fuse element can be more effectively interrupted (the fusing portion is melted) (see FIG. 6). Therefore, the overcurrent interruption time can be more effectively shortened.

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

[0068] Referring to FIGS. 7 and 8 together, 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 are connected to a soluble conductor in a state of facing each other and being close to or in contact with each other. In the example of the figure, an example of one unit constituting the protective element is shown. The unit is formed by the first conductor 411 and the second conductor 412 to which a plurality of first tip portions 11a and a plurality of second tip portions 12a are connected to the soluble conductor 13.

[0069] In the example of the figure, the first conductor 411 has five first tip portions 11a, and the second conductor 412 has five second tip portions 12a, but it is not limited thereto. For example, the first conductor 411 may have four or less or six or more first tip portions 11a, and the second conductor 412 may have four or less or six or more second tip portions 12a. For example, the number of the first tip portions 11a and the number of the second tip portions 12a may be the same as each other or different from each other. For example, the arrangement modes of the first tip portions 11a and the second tip portions 12a can be changed according to the design specifications.

[0070] In the example of the figure, each of the first conductor 411 and the second conductor 412 includes a substantially rectangular plate-shaped portion (base portion) whose left-right dimension is longer than its front-rear dimension when viewed from the vertical 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 base portion toward the tip.

[0071] In the example of the figure, each of the plurality of first tip portions 11a and each of the plurality of second tip portions 12a has a shape in which the dimension in the left - right direction becomes shorter from the base to the tip when viewed from the up - down direction, and the outer edge portion in the left - right direction is curved inward. In the present embodiment, each of the plurality of first tip portions 11a and each of the plurality of second tip portions 12a has a uniform dimension (thickness) in the up - down direction from the base to the tip, but the dimension in the left - right direction becomes shorter from the base to the tip, so that the cross - sectional area decreases from the base to the tip.

[0072] In the example of the figure, each of the plurality of first tip portions 11a has the same shape as each other when viewed from the up - down direction, and each of the plurality of second tip portions 12a has the same shape as each other when viewed from the up - down direction, but it is not limited to this. For example, each of the plurality of first tip portions 11a may have different shapes from each other when viewed from the up - down direction, or each of the plurality of second tip portions 12a may have different shapes from each other when viewed from the up - down direction. For example, the shape of each of the plurality of first tip portions 11a and each of the plurality of second tip portions 12a can be changed according to the design specifications.

[0073] In the protection element of the present embodiment described above, since each of the plurality of first tip portions 11a and each of the plurality of second tip portions 12a has a shape in which the cross - sectional area decreases from the base to the tip and the tips of each are connected by solder, it is possible to make the current flow easily while suppressing the resistance value of the entire fuse element. Therefore, the combination of the current concentration at the tip of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a and the melting phenomenon of the fusible conductor during over - current interruption can more effectively cut off (fuse the fusing part) the fuse element. Therefore, the over - current interruption time can be more effectively shortened.

[0074] (Fifth Embodiment) The protection element according to the fifth embodiment of the present invention will be described with reference to FIGS. 9 to 10. The protection element of the fifth embodiment mainly differs from the fourth embodiment described above in the configuration mode of the soluble conductor 513. In each figure of the present embodiment, for components that are the same or substantially the same as those of the first to fourth embodiments, the description may be omitted by attaching the same reference numerals and the same names.

[0075] Referring to FIGS. 9 and 10 together, 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 are opposed to each other and are connected to the soluble conductor 513 in a state of being close to or in contact with each other. In the example of the figure, an example of one unit constituting the protection element is shown. The unit is formed by the first conductor 411 and the second conductor 412 in which the first tip portion 11a and the second tip portion 12a are connected to the soluble conductor 513.

[0076] In the present 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 "laminate 513". The laminate 513 has a shape that is long in the left-right direction so as to straddle each of the plurality of first tip portions 11a and the plurality of second tip portions 12a when viewed from the up-down direction.

[0077] In the example of the figure, the laminate 513 is square or plate-shaped, with a first low melting point metal layer 513b as the inner layer and a high melting point metal layer 513a as the outer layer, and the upper surface of the outer layer is connected to the plurality of first tip portions 11a and the plurality of second tip portions 12a via a second low melting point metal layer 513c (for example, solder), but it is not limited to this. For example, the laminate 513 may have one or more low melting point metal layers, two or more high melting point metal layers, and a configuration in which the low melting point metal layer is disposed between the high melting point metal layers. This 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 mainly composed of Ag or Cu. The high melting point metal layer of the laminate 513 only needs to contain Ag or Cu, and it may be a single Ag, a single Cu, an Ag alloy, or a Cu alloy. An Ag alloy is an alloy in which the content of Ag is the highest among the metals contained in the alloy, and a Cu alloy is an alloy in which the content of Cu is the highest 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 mainly composed of Sn. The low melting point metal layer of the laminate 513 only needs to contain Sn, and it may be a single Sn or an Sn alloy. An Sn alloy is an alloy mainly composed of Sn. An Sn alloy is an alloy in which the content of Sn is the highest among the metals contained in the alloy. Examples of Sn alloys include Sn-Bi alloys, In-Sn alloys, Sn-Ag-Cu alloys, etc.

[0080] Note that the laminate 513 may have a two-layer structure of a low melting point metal layer / high melting point metal layer. Or, the laminate 513 may have two or more high melting point metal layers, one or more low melting point metal layers, and may have a multilayer structure of three or more layers in which the low melting point metal layers are arranged between the high melting point metal layers. Also, the soluble conductor 513 may be composed of a single layer of a low melting point metal layer containing Sn.

[0081] In the example of the figure, the laminate 513 is connected to the lower surface of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a, but it is not limited to this. For example, the laminate 513 may be connected to the upper surface of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a. For example, the manner of connecting each of the plurality of first tip portions 11a and the plurality of second tip portions 12a to the laminate 513 can be changed according to the design specifications.

[0082] In the protection element of the present embodiment described above, since each of the plurality of first tip portions 11a and the plurality of second tip portions 12a has a shape in which the cross-sectional area decreases from the base to the tip and the tips of each are connected to the laminate 513, it is possible to make the current flow easily while suppressing the resistance value of the entire fuse element. Therefore, due to the combination of the current concentration at the tip of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a at the time of overcurrent interruption and the melting phenomenon of the soluble conductor 513, the fuse element can be more effectively interrupted (the fusing portion is fused). Therefore, the overcurrent interruption time can be more effectively shortened.

[0083] (Sixth Embodiment) The protection element according to the sixth embodiment of the present invention will be described with reference to FIGS. 11 to 12. The protection element of the sixth embodiment is mainly different from the fifth embodiment described above in the electrical connection mode in the fuse element. In each drawing of the present embodiment, components that are the same as or substantially the same as those in the first to fifth embodiments may be denoted by the same reference numerals or the same names, and the description may be omitted.

[0084] Referring to FIGS. 11 and 12 together, the first conductor 411 and the second conductor 412 to which the first tip portion 11a and the second tip portion 12a are connected to the soluble conductor 513 form one unit (each of the plurality of units 605A, 605B). The plurality of units 605A, 605B are electrically connected in series.

[0085] In the example of the figure, the fuse element has two units 605A, 605B, and the two units 605A, 605B are electrically connected in series, but it is not limited to this. For example, the fuse element may have three or more units 605A, 605B, ···, and the three or more units 605A, 605B, ··· may be electrically connected in series. For example, the number of units 605A, 605B can be changed according to the design specifications.

[0086] In the example of the figure, each of the plurality of units 605A and 605B includes a substantially rectangular plate-shaped portion (base portion) that is longer in the left-right direction than in the front-back direction when viewed from the up-down direction, a plurality of tip portions (a plurality of first tip portions 11a and a plurality of second tip portions 12a) that taper from the base portion toward the tip, and a laminate 513 connected to the plurality of first tip portions 11a and the plurality of second tip portions 12a.

[0087] In the example of the figure, each of the plurality of units 605A and 605B has the same shape as each other when viewed from the up-down direction, but is not limited to this. For example, each of the plurality of units 605A and 605B may have different shapes from each other when viewed from the up-down direction. For example, the shape of each of the plurality of units 605A and 605B can be changed according to the design specifications.

[0088] In the protection element of the present embodiment described above, in each of the plurality of units 605A and 605B, each of the plurality of first tip portions 11a and the plurality of second tip portions 12a has a shape in which the cross-sectional area decreases from the base toward the tip, and the tips of each are connected to the laminate 513. Therefore, while suppressing the resistance value of the entire fuse element, the current can flow easily. Therefore, due to the combination of the current concentration at the tip of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a at the time of overcurrent interruption and the melting phenomenon of the soluble conductor 513, the fuse element can be more effectively interrupted (the fusing portion is fused). Therefore, the overcurrent interruption time can be more effectively shortened.

[0089] (Seventh Embodiment) The protection element according to the seventh embodiment of the present invention will be described with reference to FIGS. 13 to 14. The protection element of the seventh embodiment mainly differs in that the aspect of the laminate 713 (soluble conductor) is different from that of the sixth embodiment described above. In each figure of the present embodiment, for components that are the same as or substantially the same as those of the first to sixth embodiments, the description may be omitted by attaching the same reference numerals or the same names.

[0090] Referring to FIGS. 13 and 14 together, each of the plurality of units 705A and 705B includes a substantially rectangular plate-shaped portion (base portion) that is longer in the left-right direction than in the front-back direction when viewed from the up-down direction, a plurality of tip portions (a plurality of first tip portions 11a and a plurality of second tip portions 12a) that taper from the base portion toward the tip, and a laminate 713 connected to the plurality of first tip portions 11a and the plurality of second tip portions 12a.

[0091] In the example of the figure, the laminate 713 has a shape that is long in the left-right direction so as to straddle the entirety of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a when viewed from the up-down direction. In the example of the figure, the laminate 713 has a shape that is long in the front-back direction so as to straddle from the base of the plurality of first tip portions 11a to the base of the plurality of second tip portions 12a when viewed from the up-down direction, but is not limited thereto. For example, the laminate 713 may have a shape that is long in the front-back direction so as to straddle from the middle (between the tip and the base) of the plurality of first tip portions 11a to the middle (between the tip and the base) of the plurality of second tip portions 12a when viewed from the up-down direction. In the example of the figure, the laminate 713 has a shape that is longer in the left-right direction than the base portion when viewed from the up-down direction, but is not limited thereto. For example, the laminate 713 may have the same left-right dimension as the base portion or may be shorter in the left-right dimension than the base portion when viewed from the up-down direction. For example, the shape of the laminate 713 can be changed according to the design specifications.

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

[0093] In the protection element of the present embodiment described above, in each of the plurality of units 705A and 705B, each of the plurality of first tip portions 11a and the plurality of second tip portions 12a has a shape in which the cross-sectional area decreases from the base to the tip, and the entire tips of each are connected to the laminate 713. Therefore, while suppressing the resistance value of the entire fuse element, the current can flow easily. For this reason, the current concentration at the tip of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a at the time of overcurrent interruption and the melting phenomenon of the soluble conductor 713 combine to more effectively interrupt (fuse the fuse portion) the fuse element. Therefore, the overcurrent interruption time can be more effectively shortened.

[0094] (Eighth Embodiment) The protection element according to the eighth embodiment of the present invention will be described with reference to FIGS. 15 to 17. The protection element of the eighth embodiment is mainly different from the sixth embodiment described above in the configuration mode of the protection element. In each figure of the present embodiment, for the constituent members that are the same as or substantially the same as those of the first to seventh embodiments, the description may be omitted by attaching the same reference numerals or the same names.

[0095] Referring to FIGS. 15 to 17 together, the protection element further includes a first terminal 30 and a second terminal 40. A part of the first conductor 411 is electrically connected to the first terminal 30. A part 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 in the current conduction direction of the fuse elements 810 and 820. In the example of the figure, each of the first terminal 30 and the second terminal 40 has a plate shape that spreads in the plane direction (XY plane direction) perpendicular to the vertical direction. Each of the first terminal 30 and the second terminal 40 is in a substantially rectangular plate shape. The first terminal 30 and the second terminal 40 are arranged apart from each other in the front-rear direction.

[0097] The first terminal 30 is connected to the front end portions of the fuse elements 810 and 820. The front side portion of the first terminal 30 protrudes forward from the case 50 and is exposed outside the case 50. The second terminal 40 is connected to the rear end portion of the fuse element. The rear side portion of the second terminal 40 protrudes rearward from the case 50 and is exposed outside 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 penetrates the first terminal 30 in the vertical direction. The portion of the first terminal 30 behind the external terminal hole 31 is disposed between the terminal mounting surface 51 and the terminal pressing surface 52 at the front portion 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 penetrates the second terminal 40 in the vertical direction. The portion of the second terminal 40 in front of the external terminal hole 41 is disposed between the terminal mounting surface 51 and the terminal pressing surface 52 at the rear portion of the case 50 and is sandwiched between the terminal mounting surface 51 and the terminal pressing surface 52.

[0100] For example, among the pair of external terminal holes 31, 41, one is connected to the power supply side and the other is connected to the load side. Note that the external terminal holes 31, 41 are not limited to the above and may be connected to the current-carrying path inside the load. For example, the connection modes of the external terminal holes 31, 41 can be changed according to the 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. As the material of the first terminal 30 and the second terminal 40, it is preferable to use brass from the viewpoint of enhancing rigidity, and it is preferable to use copper from the viewpoint of reducing electrical resistance. When using copper, it is preferable to perform rust prevention treatments such as nickel plating, silver plating, or tin plating on the surface. The first terminal 30 and the second terminal 40 may be made of the same material as each other or may be made of different materials from each other. For example, the material of each of the first terminal 30 and the second terminal 40 can be changed according to the design specifications.

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

[0103] Also, the plurality of units 805A, 805B, 805C are electrically connected in series. In the example of the figure, the fuse elements 810, 820 have three units 805A, 805B, 805C, and the three units 805A, 805B, 805C are electrically connected in series, but it is not limited to this. For example, the fuse elements 810, 820 may have two or four or more units 805A, 805B, 805C, ···, and the two or four or more units 805A, 805B, 805C, ··· may be electrically connected in series. For example, the number of units 805A, 805B, 805C can be changed according to the design specifications.

[0104] In the example of the figure, each of the plurality of units 805A, 805B, 805C includes a substantially rectangular plate-shaped portion (base portion) whose left-right dimension is longer than its front-rear dimension when viewed from the up-down direction, a plurality of tip portions (a plurality of first tip portions 11a and a plurality of second tip portions 12b) that taper from the base portion toward the tip, and a laminate 513 connected to the plurality of first tip portions and the plurality of second tip portions.

[0105] In the example of the figure, each of the plurality of units 805A, 805B, 805C has the same shape as each other when viewed from the up-down direction, but it is not limited to this. For example, each of the plurality of units 805A, 805B, 805C may have different shapes from each other when viewed from the up-down direction. For example, the shape of each of the plurality of units 805A, 805B, 805C can be changed according to the design specifications.

[0106] In the example of the figure, a plurality of units 805A, 805B, 805C (hereinafter also referred to as "assemblies 806A, 806B") that are electrically connected in series are electrically connected in parallel. Assemblies 806A, 806B constitute fuse elements 810, 820. Fuse elements 810, 820 are composed of a metal plate-like member, a sheet-like member, a metal foil, or the like. In the example of the figure, two fuse elements 810, 820 are provided. The two fuse elements 810, 820 are arranged in parallel with each other. The two fuse elements 810, 820 are arranged 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 on the lower surface side of the first terminal 30 and the second terminal 40 and spans between them. The second fuse element 820 is arranged on the upper surface side of the first terminal 30 and the second terminal 40 and spans between them.

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

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

[0110] Note that the connection mode between each terminal 30, 40 and each fuse element 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 mode between each terminal 30, 40 and each fuse element 810, 820 can be changed according to the design specifications.

[0111] The protection element further includes a case 50. The case 50 encloses a part 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 has a cylindrical shape that extends in the front-rear direction as a whole. A filler 70 is encapsulated in at least a part of the gap inside the case 50.

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

[0113] Silica sand is granular SiO 2 (quartz glass). Silica sand is sand mainly composed of quartz grains. Specifically, silica sand is a sandy sediment or weathering product mainly composed of silicates, especially one containing a large amount of quartz grains, and is white coarse-grained sand.

[0114] For example, examples of the inorganic fiber material include fiber materials such as insulating fibers. For example, examples of the fiber material include SiO 2 and MgO, Al 2 O 3 , ZrO 2 and other ceramic materials, or plastic materials such as nylon and PMMA. Note that the form of the fiber material is not limited to the above and can be changed according to the design specifications.

[0115] For example, examples of the ceramic fiber include ceramic fiber paper. Although not shown in the figure, a plurality of ceramic fiber papers may be laminated and arranged in the gaps in the case 50.

[0116] Silicone resin is also referred to as silicon resin, and generally refers to a polymer having an organic substituent obtained by hydrolyzing a silane compound and polymerizing it with a siloxane bond, and is also referred to as a hybrid polymer in which inorganic and organic are fused.

[0117] Note that the filler 70 is not limited to the above, and various materials can be used. For example, the filler 70 may be a spherical member (e.g., ceramic beads or ceramic balls) formed 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) formed 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) formed 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) formed of a plastic material such as nylon or PMMA. For example, the filler 70 may be formed of a sheet-like member or may have a shape such as wool, board, or block. For example, the filler 70 may be a plate-like member (e.g., plate-like ceramic) formed 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 siloxane bond in which silicon (Si) and oxygen (O) are repeatedly arranged as a main chain. For example, the form of the filler 70 can be changed according to the design specifications.

[0118] In the example of the figure, the filler 70 is filled in the gap in the case 50. A part of the filler 70 is in contact with a part of the first fuse element 810 and the second fuse element 820. For example, first, a part of the first terminal 30 and the second terminal 40 and a part of the first fuse element 810 and the second fuse element 820 are sandwiched by the case 50. Then, the filler 70 can be filled in the gap in the case 50 by putting the filler 70 into the case 50 through a through hole (not shown) formed in the case 50.

[0119] Note that the filler 70 is not limited to being completely filled in the case 50 without gaps, and may be filled with a gap in a part of the case 50. For example, it is sufficient that the filler 70 is enclosed in at least a part of the gap in the case 50.

[0120] The case 50 is close to or in contact with both sides of two fuse elements 810, 820 (an example of one or more units). In the example of the figure, the case 50 is in contact with the lower surface of the first fuse element 810 and the upper surface of the second fuse element 820 at the terminal mounting surface 51 and the terminal pressing surface 52 formed at both front and rear ends thereof.

[0121] The case 50 includes a plurality of holding members 50A, 50B. In the example of the figure, two holding members 50A, 50B are provided. The two holding members 50A, 50B are arranged adjacent to each other in the vertical direction. Among 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 arranged 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 concave and recessed downward from the upper surface of the first holding member 50A. The bottom surface of the terminal mounting surface 51 is planar and faces upward, and extends in a plane direction (XY plane direction) perpendicular to the vertical direction. A pair of terminal mounting surfaces 51 are provided on the first holding member 50A. The pair of terminal mounting surfaces 51 are arranged at both front and rear ends of the first holding member 50A in the front-rear direction.

[0123] The second holding member 50B is arranged 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 planar and faces downward, and extends in a plane direction (XY plane direction) perpendicular to the vertical direction. A pair of terminal pressing surfaces 52 are provided on the second holding member 50B. The pair of terminal pressing surfaces 52 are arranged at both front and rear ends of the second holding member 50B in the front-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] In a state where 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. A part of the first fuse element 810 and the second fuse element 820 is accommodated in the accommodation space 55. In the accommodation space 55, a filler 70 is enclosed in a gap other than the part where the first fuse element 810 and the second fuse element 820 are accommodated.

[0125] The protection element further includes an outer shell member 60 that covers the outside of the case 50 and fixes a plurality of holding members. The outer shell member 60 is in a cylindrical shape extending in the front-rear direction. In the example of the figure, the outer shell member 60 has a cylindrical shape that opens in the front-rear direction. The two holding members 50A and 50B are accommodated in the outer shell member 60 in a state where they are combined side by side in the vertical direction. The outer shell member 60 holds the two holding members 50A and 50B in a fixed state by adhesion or the like.

[0126] For example, it is preferable that the outer shell member 60 and each of the holding members 50A and 50B are formed of a material having a comparative tracking index CTI (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more. The comparative tracking index CTI can be obtained by a test based on IEC60112.

[0127] As the material of the outer shell member 60 and each of the holding members 50A and 50B, a resin material can be used. The resin material has a smaller heat capacity and a lower melting point than the ceramic material. Therefore, when a resin material is used as the material of the holding members 50A and 50B, it has the characteristics of weakening the arc discharge by gasification cooling (ablation), and when the molten and scattered metal particles adhere to the holding members 50A and 50B, the surface of the holding members 50A and 50B is deformed or the deposits are aggregated, so that the metal particles become sparse and it is difficult to form a conduction path, which is preferable.

[0128] As the resin material, for example, a polyamide-based resin or a fluorine-based resin can be used. In the present embodiment, the case 50 is made of a polyamide-based resin or a fluorine-based resin. The polyamide-based resin may be an aliphatic polyamide or a semi-aromatic polyamide. Examples of the aliphatic polyamide include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of the semi-aromatic polyamide include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. An example of the fluorine-based resin is polytetrafluoroethylene. Also, the polyamide-based resin and the fluorine-based resin have high heat resistance and are difficult to burn. In particular, even when the aliphatic polyamide burns, it is difficult to generate graphite. Therefore, by forming the outer shell member 60 and the respective holding members 50A and 50B using the aliphatic polyamide, it is possible to more reliably prevent a new current path from being formed by the graphite generated by the arc discharge at the time of fusing of each fuse element.

[0129] In the protection element of the present embodiment described above, in each of the plurality of units 805A, 805B, and 805C, each of the plurality of first tip portions 11a and the plurality of second tip portions 12a has a shape in which the cross-sectional area decreases from the base to the tip, and the tips of each are connected to the laminate 513. Therefore, while suppressing the resistance value of the entire fuse elements 810 and 820, the current can easily flow. Therefore, due to the combination of the current concentration at the tips of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a at the time of overcurrent interruption and the melting phenomenon of the fusible conductor 513, the fuse elements 810 and 820 can be more effectively interrupted (the fusing portion is fused). Therefore, the overcurrent interruption time can be more effectively shortened.

[0130] In the present embodiment, the protection element further includes a case 50. The case 50 encloses a part of the first terminal 30 and the second terminal 40, and the two fuse elements 810 and 820. The filler 70 is encapsulated in at least a part of the gap inside the case 50. According to this configuration, since each fuse element 810, 820 is surrounded by the filler 70, it is possible to eliminate as much as possible the gas which is one of the sources of arc discharge generated during overcurrent interruption, around each fuse element 810, 820. Thereby, it is possible to suppress the plasma generated by the ionization of the gas which is one of the sources of arc discharge, and suppress the arc discharge.

[0131] In the present embodiment, the case 50 includes a plurality of holding members 50A, 50B. The protection element further includes an outer shell member 60 that covers the outside of the case 50 and fixes the plurality of holding members 50A, 50B. According to this configuration, the pressure (external force) acting on the case 50 during overcurrent interruption can be suppressed by the outer shell member 60.

[0132] (9th Embodiment) The protection element according to the 9th embodiment of the present invention will be described with reference to FIGS. 18 to 20. The protection element of the 9th embodiment is mainly different from the 8th embodiment described above in the configuration mode of the protection element. In each figure of the present embodiment, components that are the same as or substantially the same as those of the 1st to 8th embodiments may be denoted by the same reference numerals or the same names, and the description may be omitted.

[0133] Referring to FIGS. 18 to 20 together, the protection element further includes a case 950 and two insulating members 90A and 90B (an example of one or more insulating members). The first conductor 411 and the second conductor 412, to which the first tip 11a and the second tip 12a are connected to the soluble conductor 513, form one unit (each of the plurality of units 805A, 805B, 805C). The two insulating members 90A and 90B are close to or in contact with both sides of one fuse element 820 (an example of one or more units). The case 950 encloses a part of the first terminal 30 and the second terminal 40, one fuse element 820, and two insulating members 90A and 90B. An internal pressure buffer space 95 is formed between the case 950 and the insulating members 90A and 90B. Flow paths 97 are formed in the insulating members 90A and 90B (an example of an insulating member and / or a case) to release the 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 close to or in contact with the fuse element 820. In the example of the figure, the case 950 is in contact with the upper surface of the fuse element 820 at a part of the terminal clamping surfaces 951 and 952 (including the terminal mounting surface and the terminal pressing surface) formed at both front and rear ends thereof.

[0135] The case 950 includes a plurality of holding members 950A and 950B. In the example of the figure, two holding members 950A and 950B are provided. The two holding members 950A and 950B are arranged adjacent to each other in the left-right direction. Of the two holding members 950A and 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 on the left side 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, recessing from the right side surface of the first holding member 950A to the left side. Each of the upper and lower surfaces of the terminal clamping surface 951 is planar and extends in a surface direction (XY plane direction) perpendicular to the vertical 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 in the front-rear direction of the first holding member 950A.

[0137] The second holding member 950B is disposed on the right side 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, recessing from the left side surface of the second holding member 950B to the right side. Each of the upper and lower surfaces of the terminal clamping surface 952 is planar and extends in a surface direction (XY plane direction) perpendicular to the vertical 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 in the front-rear direction of the second holding member 950B.

[0138] The protection element further includes an outer shell member 60 that covers the outside of the case 950 and fixes the plurality of holding members 950A and 950B. The outer shell member 60 is cylindrical and extends in the front-rear direction. In the example of the figure, the outer shell member 60 has a cylindrical shape that opens in the front-rear direction. The two holding members 950A and 950B are accommodated in the outer shell member 60 in a state of being combined side by side in the left-right direction. The outer shell member 60 holds the two holding members 950A and 950B in a fixed state by adhesion or the like.

[0139] For example, it is preferable that the outer shell member 60 and each of the holding members 950A and 950B are formed of a material having a comparative tracking index CTI (resistance to tracking (carbonized conduction path) breakdown) of 500 V or more. The comparative tracking index CTI can be obtained by a test based on IEC60112.

[0140] As the material of the outer shell member 60 and each of the holding members 950A and 950B, a resin material can be used. The resin material has a smaller heat capacity and a lower melting point than the ceramic material. Therefore, when a resin material is used as the material of the holding members 950A and 950B, it has the characteristics of weakening the arc discharge by gasification cooling (ablation), and when the molten and scattered metal particles adhere to the holding members 950A and 950B, the surface of the holding members 950A and 950B is deformed or the adherents are aggregated, so that the metal particles are sparse and it is difficult to form a conduction path, which is preferable.

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

[0142] Each of the two insulating members 90A and 90B is plate-shaped, and a pair of plate surfaces face in the vertical direction. Each of the two insulating members 90A and 90B forms a rectangular plate shape with a smaller dimension in the left-right direction than the dimension in the front-rear direction when viewed from the vertical direction. Among the two insulating members 90A and 90B, the one arranged on the lower side is also referred to as the "first insulating member 90A", and the one arranged on the upper side is also referred to as the "second insulating member 90B".

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

[0144] The first insulating member 90A includes a terminal support surface 91. The terminal support surface 91 is a concave shape that depresses downward from the upper surface of the first insulating member 90A. The bottom surface of the terminal support surface 91 is a planar surface facing upward and extends in the surface direction (XY plane direction) perpendicular to the vertical direction. A pair of terminal support surfaces 91 are provided on the first insulating member 90A. The pair of terminal support surfaces 91 are arranged at both ends in the front-rear direction of the first insulating member 90A.

[0145] In the first insulating member 90A, a flow path 97 (for example, a leakage hole and / or a gap) that opens in the vertical direction and extends in the lateral direction is formed outside the soluble conductor 513 in the front-rear direction. The flow path 97 extends in a direction orthogonal to the energization direction (substantially the front-rear direction) in which current flows through the fuse element 820. When the flow path 97 is formed in the first insulating member 90A, the molten and scattered matter adhering to the upper surface of the first insulating member 90A after the fuse element 820 is cut off becomes discontinuous at the flow path 97, and the insulation resistance between the first terminal 30 and the second terminal 40 after the cut-off 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 close to or in contact with the upper surface of the fuse element 820.

[0147] In the second insulating member 90B, a flow path 97 (for example, a leakage hole and / or a gap) that opens in the vertical direction and extends in the lateral direction is formed outside the soluble conductor 513 in the front-rear direction. The flow path 97 extends in a direction orthogonal to the energization direction (substantially the front-rear direction) in which current flows through the fuse element 820. When the flow path 97 is formed in the second insulating member 90B, the molten and scattered matter adhering to the lower surface of the second insulating member 90B after the fuse element 820 is cut off becomes discontinuous at the flow path 97, and the insulation resistance between the first terminal 30 and the second terminal 40 after the cut-off can be suitably increased.

[0148] In the example of the figure, two leak holes serving as the flow path 97 are arranged at intervals in the front-rear direction. The leak holes extend linearly along the vertical direction. For example, the opening area of the leak hole (the cross-sectional area when the leak hole is cut by a plane orthogonal to the vertical direction) is 20% or less of the length in the energization direction of the area where the insulating members 90A, 90B and the fuse element 820 are close to or in contact with each other in the area where the insulating members 90A, 90B and the fuse element 820 are close to or in contact with each other, and there is no limitation outside the area where the insulating members 90A, 90B and the fuse element 820 are close to or in contact with each other. Note that the form of the leak hole (number, arrangement location, shape, opening area, etc.) is not limited to the above and can be changed according to the design specifications.

[0149] In a state where the above members 90A, 90B, 950A, 950B are combined, an element accommodation space 96 is formed between the first insulating member 90A and the second insulating member 90B. The fuse element 820 is accommodated in the element accommodation space 96.

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

[0151] In a state where the first holding member 950A and the second holding member 950B are combined, an internal pressure buffer space 95 is formed between the first holding member 950A and the second holding member 950B. The internal pressure buffer space 95 communicates with the element accommodation space 96 through the flow path 97. The internal pressure buffer space 95 has the effect of suppressing a rapid increase in the internal pressure of the protection element due to the gas generated by the arc discharge generated when the fuse element 820 is blown.

[0152] The internal pressure buffer space 95 is filled with a filling material 70. The filling material 70 includes an arc extinguishing agent, silica sand, an inorganic fiber material, ceramic fiber, or a silicone resin. For example, the filling material 70 can further include one or more materials selected from the group consisting of an arc extinguishing agent, silica sand, an inorganic fiber material, ceramic fiber, or a silicone resin and / or a mixture thereof, and preferably includes silica sand or an inorganic fiber material.

[0153] In the example of the figure, the filling material 70 is filled in the internal pressure buffer space 95 inside the protection element. A part of the filling material 70 is in contact with the lower surface of the first insulating member 90A located below the fuse element 820. A part of the filling material 70 is in contact with the upper surface of the second insulating member 90B located above the fuse element 820.

[0154] For example, first, a part of the first terminal 30 and the second terminal 40 and a part of the fuse element 820 are sandwiched by a case 950. Then, the filling material 70 can be filled into the internal pressure buffer space 95 by putting the filling material 70 into the case 950 (internal pressure buffer space 95) through a through hole (not shown) formed in the case 950.

[0155] Note that the filling material 70 is not limited to being completely filled in the internal pressure buffer space 95 without gaps, and may be filled with gaps in a part of the internal pressure buffer space 95. For example, the filling material 70 may be disposed in at least a part of the internal pressure buffer space 95.

[0156] Note that the posture of the protection element is not limited to being arranged such that its vertical direction is along the direction of gravity, and may be arranged to intersect the direction of gravity. For example, when the filling material 70 is filled in the internal pressure buffer space 95 without gaps, the protection element may be arranged to be inclined with respect to the direction of gravity. For example, the arrangement mode of the protection element can be changed according to the design specifications.

[0157] In the protection element of the present embodiment described above, in each of the plurality of units 805A, 805B, 805C, each of the plurality of first tip portions 11a and the plurality of second tip portions 12a has a shape in which the cross-sectional area decreases from the base toward the tip, and the tips of each are connected to the laminate 513. Therefore, while suppressing the resistance value of the entire fuse element 820, the current can flow easily. For this reason, combined with the current concentration at the tip of each of the plurality of first tip portions 11a and the plurality of second tip portions 12a at the time of overcurrent interruption and the melting phenomenon of the soluble conductor 513, the fuse element 820 can be more effectively interrupted (the fusing portion is fused). Therefore, the overcurrent interruption time can be more effectively shortened.

[0158] In the present embodiment, the protection element further includes a case 950 and two insulating members 90A, 90B. The two insulating members 90A, 90B are close to or in contact with both surfaces of one fuse element 820. The case 950 encloses a part of the first terminal 30 and the second terminal 40, one fuse element 820, and the two insulating members 90A, 90B. An internal pressure buffer space 95 is formed between the case 950 and the insulating members 90A, 90B. In the insulating members 90A, 90B, a flow path 97 is formed for discharging the high-temperature gas generated between the internal pressure buffer space 95 and the fuse element 820 when the fuse element 820 is interrupted. According to this configuration, since the space formed between the fuse element 820 and the insulating members 90A and 90B becomes narrow, it is possible to eliminate as much as possible the gas, which is one of the sources of arc discharge generated during overcurrent interruption, around the fuse element 820. Thereby, it is possible to suppress the plasma generated by the ionization of the gas, which is one of the sources of arc discharge, and suppress the arc discharge. In addition, in order to suppress the arc discharge, it is not necessary to fill the periphery of the fuse element 820 with silica sand called an arc extinguishing agent. Therefore, problems caused by the continuous adhesion of molten and scattered matter to the surface of the arc extinguishing agent (problems such as deterioration of the interruption characteristics and reduction of the insulation resistance after interruption) do not occur. Therefore, it is possible to suppress the arc discharge during interruption, handle high voltage and large current interruption, and suppress the reduction of the insulation resistance after interruption. In addition, through the flow paths 97 formed in the insulating members 90A and 90B, it is possible to discharge the gasified (metal gas) fuse element 820.

[0159] In this embodiment, the insulating members 90A and 90B are made of a nylon-based resin or a fluorine-based resin. According to this configuration, the nylon-based resin and the fluorine-based resin have high heat resistance and are difficult to burn. Among nylon-based resins, in particular, aliphatic polyamide is less likely to generate graphite even when burned. Therefore, by forming the insulating members 90A and 90B from aliphatic polyamide, it is possible to more reliably prevent the generation of graphite due to arc discharge during the fusing of the fuse element 820 and the formation of a new current path. In addition, since carbon black for coloring also leads to graphite generation, a material that does not contain carbon black (for example, a natural-colored resin material) is more preferable.

[0160] In this embodiment, a filler 70 is enclosed in the internal pressure buffer space 95. According to this configuration, while suppressing the occurrence of arc discharge by the insulating members 90A and 90B, the rapid increase in the internal pressure of the protection element due to the molten and scattered matter entering the internal pressure buffer space 95 can be sufficiently suppressed by the filler 70. 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, an inorganic fiber material, ceramic fiber, or a silicone resin. When the filler 70 contains at least silica sand, the surface area can be ensured for each particle of the silica sand, and it is easier to increase the surface area of the entire filler 70 compared to the case of a plate shape. Therefore, it is easier to further suppress the rapid increase in the internal pressure of the protection element due to the molten and scattered matter entering the internal pressure buffer space 95. When the filler 70 contains at least an inorganic fiber material, the surface area of the filler 70 can be ensured, and it is easier to increase the surface area of the entire filler 70 compared to the case of a plate shape. In addition, when the filler 70 contains at least an inorganic fiber material, there are more elements for capturing the molten and scattered matter compared to the case of a plate shape. Therefore, it is easier to further suppress the rapid increase in the internal pressure of the protection element due to the molten and scattered matter entering the internal pressure buffer space 95.

[0162] In this embodiment, the case 950 includes a plurality of holding members 950A and 950B. The protection element further includes an outer shell member 60 that covers the outside of the case 950 and fixes the plurality of holding members 950A and 950B. According to this configuration, the pressure (external force) acting on the case 950 during overcurrent interruption can be suppressed by the outer shell member 60.

[0163] The present invention may combine each configuration described in the foregoing embodiments and modifications within the scope not departing from the gist of the present invention, and addition, omission, substitution, and other changes of the configuration are possible. The present invention is not limited by the foregoing embodiments, etc., but is limited only by the scope of the claims.

Explanation of Reference Numerals

[0164] 1 Unit 11 First conductor 11a First tip 12 Second conductor 12a Second tip 13 Soluble 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 Filling material 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 Soluble conductor (laminate) 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 Soluble conductor (laminate) 805A, 805B, 805C Unit 950 Case 950A First holding member (holding member) 950B Second holding member (holding member)

Claims

1. a first conductor having at least one first tip; a second conductor; and the first tip has a shape in which the cross-sectional area decreases from the base to the tip, at least a part of the first tip and the second conductor are connected to a soluble conductor having a melting temperature lower than that of each of the first conductor and the second conductor, a protection element.

2. the second conductor has at least one second tip, the second tip has a shape in which the cross-sectional area decreases from the base to the tip, at least a part of the first tip and the second tip are connected to the soluble conductor, the protection element according to claim 1.

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

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

5. each of the first conductor and the second conductor is made of Ag or Cu, or a metal mainly composed of Ag or Cu, the protection element according to any one of claims 1 to 3.

6. the soluble conductor is made of Sn or a metal mainly composed of Sn, the protection element according to any one of claims 1 to 3.

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

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

9. the first conductor has a plurality of the first tips, the second conductor has a plurality of the second tips, the plurality of first tips and the plurality of second tips face each other and are connected to the soluble conductor in a state of being close to or in contact with each other, the protection element according to claim 2 or 3.

10. further comprising a first terminal and a second terminal, a part of the first conductor is electrically connected to the first terminal, a part of the second conductor is electrically connected to the second terminal, the protection element according to claim 2 or 3.

11. the first conductor and the second conductor to which the first tip and the second tip are connected to the soluble conductor form one unit, The plurality of the units are electrically connected in series. The protection element according to claim 10.

12. The first conductor and the second conductor, wherein the first tip and the second tip are connected to the soluble conductor, form one unit. The plurality of the units are electrically connected in parallel. The protection element according to claim 10.

13. Further comprising a case, The first conductor and the second conductor, wherein the first tip and the second tip are connected to the soluble conductor, form one unit. The case encloses a part of the first terminal and the second terminal and one or more of the units. At least a part of the gap in the case is filled with a filler. The protection element according to claim 2.

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

15. Further comprising a case, The first conductor and the second conductor, wherein the first tip and the second tip are connected to the soluble conductor, form one unit. Each of the first conductor and the second conductor is a plate-like member made of metal. The case encloses a part of the first terminal and the second terminal and one or more of the units and is close to or in contact with both surfaces of one or more of the units. The protection element according to claim 2.

16. Further comprising a case and one or more insulating members, The first conductor and the second conductor, wherein the first tip and the second tip are connected to the soluble conductor, form one unit. Each of the first conductor and the second conductor is a plate-like member made of metal. One or more of the insulating members are close to or in contact with both surfaces of one or more of the units. The case encloses a part 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 buffer space is formed between the case and the insulating member. A flow path is formed in the insulating member and / or the case for discharging high-temperature gas generated between the internal pressure buffer space and the unit when the unit is interrupted. The protection element according to claim 2.

17. The insulating member is made of a nylon-based resin or a fluorine-based resin. The protection element according to claim 16.

18. The internal pressure buffer space is filled with a filler. The protection element according to claim 16.

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

20. The case includes a plurality of holding members. The case further includes an outer shell member that covers the outside of the case and fixes the plurality of holding members. The protection element according to any one of claims 13, 15, and 16.

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