Protection Elements

Abstract

To provide a protection element capable of handling a high voltage and a high current, and capable of realizing both cutting off of excess current and cut off functionality by a cut off signal.SOLUTION: A fusion space 12 is divided into a first space 12a at which a first fuse element 7 locates across a slider 14 and a second space 12b connected to a cutting space 13. The slider 14 includes a cutting part 14a projecting toward the cutting space 13 from the second space 12b. When the first fuse element 7 melts by a fusion current flowing through the first fuse element 7, arc discharge occurs in the first space 12a, and the slider 14 moves toward a side of a second fuse element 10A as the pressure in the first space 12a rises and the cutting part 14a cuts the second fuse element 10A.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, there is a fuse element that generates heat and melts to interrupt the current path when a current exceeding its rated value flows. Protective devices (fuse elements) equipped with the fuse element are used, for example, in battery packs that use lithium-ion secondary batteries.

[0003] In recent years, lithium-ion secondary batteries have been used in a wide range of fields, including not only mobile devices but also electric vehicles and storage batteries. Therefore, the capacity of lithium-ion secondary batteries is being increased. Accordingly, there is a demand for protective elements to be installed in battery packs that have large-capacity lithium-ion batteries and high-voltage, large-current current paths.

[0004] As a protection element capable of handling high voltages and large currents (for example, 100 V / 100 A or more), trigger-interruption fuses such as pyrofuses are being adopted instead of melting fuses (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6433518 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the above-mentioned conventional protection elements, as the voltage and current increase, the case size becomes larger and the material costs increase, resulting in a high-cost current fuse. Furthermore, protection elements that have been available up to now for high voltages and large currents only cut off overcurrents, and none have also been able to cut off using a cutoff signal.

[0007] The present invention has been proposed in view of the above-mentioned conventional circumstances, and aims to provide a protection element that can handle high voltages and large currents and that can achieve both an overcurrent cut-off function and a cut-off function based on a cut-off signal. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides the following means. [1] A first fuse element portion having a first terminal and a second terminal, and a first fuse element electrically connecting the first terminal and the second terminal; a second fuse element portion having a third terminal and a fourth terminal, and a second fuse element electrically connecting the third terminal and the fourth terminal; an insulating casing having a fusing space in which the first fuse element is located and a cutting space in which the second fuse element is located, the insulating casing electrically insulating the first fuse element portion and the second fuse element portion while holding the first fuse element portion and the second fuse element portion; a slider located between the first fuse element and the second fuse element, the slider being arranged to be movable toward the second fuse element within the fusing space; the fusing space is divided into a first space in which the first fuse element is located across the slider, and a second space connected to the cutting space; the slider has a cutting portion protruding from the second space toward the cutting space, A protection element characterized in that, when a fusing current flows through the first fuse element and the first fuse element melts, an arc discharge occurs in the first space, and as the pressure in the first space increases, the slider moves toward the second fuse element, and the cutting portion cuts off the second fuse element. [2] The protection element according to [1], characterized in that after the cutting portion cuts the second fuse element, the cutting portion shields the cut portion of the second fuse element within the cutting space. [3] The second fuse element has a structure in which a plurality of conductive members are stacked with insulating members interposed therebetween, The protection element according to [1] or [2], wherein the insulating member has a gap corresponding to the cutting space. [4] The protection element according to any one of [1] to [3], further comprising a cylindrical insulating cover that houses the insulating casing therein. [5] The protection element according to any one of [1] to [4], wherein the melting point of the second fuse element is higher than the melting point of the first fuse element. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to provide a protection element that can handle high voltages and large currents and that can achieve both the blocking of overcurrent and the blocking function based on a blocking signal. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing the appearance of a protection element according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of the protection element shown in FIG. [Figure 3] 2 is a circuit diagram showing an example of a configuration of a protection circuit using the protection element shown in FIG. 1. [Figure 4] 3 is a cross-sectional view showing a state in which the current of the protection element shown in FIG. 2 is interrupted. [Figure 5] FIG. 4 is a cross-sectional view showing the configuration of a protection element according to a second embodiment of the present invention. [Figure 6] 6 is a cross-sectional view showing a state in which the current of the protection element shown in FIG. 5 is interrupted. [Figure 7]FIG. 10 is a cross-sectional view showing the configuration of a protection element according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of a protection element according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing the configuration of a protection element according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the drawings used in the following description may show characteristic parts in a schematic manner for the sake of convenience in order to make the features easier to understand, and the dimensional ratios of the components may not necessarily be the same as those in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not necessarily limited to them, and can be implemented with appropriate changes within the scope that does not change the gist of the present invention.

[0012] (First embodiment) First, a protection element 1A shown in, for example, FIGS. 1 to 4 will be described as a first embodiment of the present invention. Fig. 1 is a perspective view showing the appearance of the protection element 1A. Fig. 2 is a cross-sectional view showing the configuration of the protection element 1A. Fig. 3 is a circuit diagram showing an example of the configuration of a protection circuit 100 using the protection element 1A. Fig. 4 is a cross-sectional view showing a state in which the current of the protection element 1A is interrupted.

[0013] As shown in Figures 1 and 2, the protection element 1A of this embodiment comprises a first fuse element portion 2 and a second fuse element portion 3 that are parallel to each other, an insulating housing 4 that holds the first fuse element portion 2 and the second fuse element portion 3 while electrically insulating the first fuse element portion 2 from the second fuse element portion 3, and an insulating cover 5 that houses the insulating housing 4 inside.

[0014] The first fuse element portion 2 has a first terminal 6a, a second terminal 6b, and a first fuse element 7 that electrically connects the first terminal 6a and the second terminal 6b.

[0015] The first terminal 6a and the second terminal 6b are made of a metal material such as copper (Cu) and are formed in the shape of a substantially rectangular plate. The first terminal 6a and the second terminal 6b are arranged in a straight line on the same plane with one end side (inside the first fuse element portion 2) facing each other.

[0016] Furthermore, on the other end side (outside the first fuse element portion 2) of each of the first terminal 6a and the second terminal 6b, a terminal hole 8 for external connection is provided as a circular opening.

[0017] The first fuse element 7 is made of a metal material such as copper (Cu), silver (Ag), tin (Sn) alloy, lead (Pb) alloy, or a laminate of tin (Sn) alloy and silver (Ag) as a fusible conductor, and is formed in the shape of an approximately rectangular flat plate.

[0018] The first fuse element 7 is attached by soldering, welding, or the like to one surface (the lower surface in this embodiment) of the first terminal 6a and the second terminal 6b, with one end of the first terminal 6a and one end of the second terminal 6b connected to each other.

[0019] The second fuse element portion 3 has a third terminal 9a, a fourth terminal 9b, and a second fuse element 10A that electrically connects the third terminal 9a and the fourth terminal 9b.

[0020] The third terminal 9a and the fourth terminal 9b are made of the same material as the first terminal 6a and the second terminal 6b, and are formed in a substantially rectangular plate shape. The third terminal 9a and the fourth terminal 9b are arranged in a straight line on the same plane, with one end side (inside the second fuse element portion 3) facing each other.

[0021] Furthermore, on the other end side (outside the second fuse element portion 3) of each of the third terminal 9a and the fourth terminal 9b, a terminal hole 11 for external connection is provided as a circular opening.

[0022] The second fuse element 10A is made of a metal material such as copper (Cu), silver (Ag), tin (Sn) alloy, or lead (Pb) alloy as a connecting conductor, and is formed in a substantially rectangular flat plate shape.

[0023] The second fuse element 10A is made of a material with a higher melting point than the first fuse element 7. For example, in this embodiment, the first fuse element 7 is made of a laminate of tin (Sn) alloy and silver (Ag), and the second fuse element 10A is made of copper (Cu), which has a higher melting point than the first fuse element 7.

[0024] The second fuse element 10A is attached by soldering, welding, or the like to one surface (the upper surface in this embodiment) of the third terminal 9a and the fourth terminal 9b, with one end of the third terminal 9a and one end of the fourth terminal 9b connected to each other.

[0025] The insulating housing 4 has a first case 4a, a second case 4b, and a third case 4c made of an insulating material, which will be described later, and is formed into an elongated cylindrical shape as a whole. However, the insulating housing 4 is not necessarily limited to this shape, and can be modified as appropriate.

[0026] The insulating housing 4 is constructed by combining the first case 4a, the second case 4b, and the third case 4c together, with the first fuse element portion 2 sandwiched between the first case 4a and the second case 4b, and the second fuse element portion 3 sandwiched between the second case 4b and the third case 4c.

[0027] As a result, the insulating housing 4 holds the first fuse element portion 2 and the second fuse element portion 3 while exposing the other end sides of the first terminal 6a and the second terminal 6b and the other end sides of the third terminal 9a and the fourth terminal 9b to the outside from both ends of the axial direction, and electrically insulates the first fuse element portion 2 and the second fuse element portion 3.

[0028] A fusing space 12 in which the first fuse element 7 is located and a cutting space 13 in which the second fuse element 10A is located are provided inside the insulating housing 4. A slider 14 is also disposed in the fusing space 12. The fusing space 12 is further divided by the slider 14 into a first space 12a in which the first fuse element 7 is located and a second space 12b connected to the cutting space 13.

[0029] The fusing space 12 is located in the middle of the first fuse element 7 and forms a space perpendicular to the axial direction of the insulating casing 4, extending between the first case 4a and the second case 4b. The shape of the fusing space 12 is not particularly limited, but examples thereof include a circular cylinder and a rectangular parallelepiped.

[0030] The cutting space 13 is located in the middle of the second fuse element 10A and forms a slit-like space perpendicular to the axial direction of the insulating casing 4, extending between the second case 4b and the third case 4c. The position of the cutting space 13 is not limited to the middle of the second fuse element 10A described above, and may be, for example, shifted toward the third terminal 9a.

[0031] On the other hand, the slider 14 is made of an insulating material such as nylon, Teflon (registered trademark), or LCP, and is formed into a plate shape that is thinner than the fusing space 12. The slider 14 may also be made of a metal whose surface has been subjected to an insulating treatment. Specifically, for example, an aluminum alloy material whose surface has been subjected to an anodized treatment can be used.

[0032] The slider 14 is disposed within the fusing space 12, positioned between the first fuse element 7 (first space 12a) and the second fuse element 10A (second space 12b) of the fusing space 12. As a result, the slider 14 is disposed within the fusing space 12 so as to be freely movable toward the second fuse element 10A side (the lower side in this embodiment).

[0033] The slider 14 also has a rectangular, flat cutting portion 14a protruding from the surface (the lower surface in this embodiment) facing the second space 12b. The cutting portion 14a extends from the second space 12b toward the cutting space 13, and its tip is inserted into the cutting space 13 to come into contact with the second fuse element 10A.

[0034] The insulating cover 5 is made of an insulating material described later, and has a shape that covers the entire outer periphery of the insulating casing 4. By seamlessly covering the entire periphery of the insulating casing 4, the insulating cover 5 can prevent the insulating casing 4 from being destroyed by arc discharge that occurs when the first fuse element 7 described later melts.

[0035] The insulating casing 4 and the insulating cover 5 are preferably made of an insulating material having a CTI (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more. The CTI can be determined by a test based on IEC60112.

[0036] Specifically, it is preferable to use a resin material, which has a smaller heat capacity and a lower melting point than ceramic materials, as the insulating material for the insulating casing 4 and insulating cover 5. Furthermore, resin materials have the property of weakening arc discharge caused by gasification cooling (ablation), and when metal particles scattered by the melted first fuse element 7 adhere to the insulating casing 4, the surface of the insulating cover 5 is deformed or the adhered particles aggregate, making it difficult to form a sparse conductive path.

[0037] Specific examples of resin materials that can be used include polyamide resins and fluorine-based resins. The polyamide resins may be aliphatic polyamides or semi-aromatic polyamides.

[0038] Examples of aliphatic polyamides include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of semi-aromatic polyamides include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. An example of a fluororesin is polytetrafluoroethylene. Furthermore, polyamide resins and fluororesins are highly heat resistant and resistant to combustion.

[0039] In particular, aliphatic polyamides are less likely to produce graphite when burned, and therefore, by using aliphatic polyamides to form the insulating casing 4 and the insulating cover 5, it is possible to more reliably prevent the formation of a new current path due to graphite produced by arc discharge when the first fuse element 7, which will be described later, melts.

[0040] The protection element 1A of this embodiment having the above-described configuration is suitably used in, for example, a protection circuit 100 as shown in Fig. 3. Specifically, in this protection circuit 100, an auxiliary power supply 101 is connected to one end of a first fuse element section 2 that serves as a sub-fuse, and a current detection circuit 103 is connected to the other end of the first fuse element section 2 via a switch 102.

[0041] On the other hand, in the protection circuit 100, a main power supply 104 is connected to one end of the second fuse element section 3 that serves as a main fuse, and a load circuit 105 is connected to the other end of the second fuse element section 3.

[0042] In the protection circuit 100, when the current detection circuit 103 detects an abnormality caused by damage to a device equipped with a main power supply, such as an accident involving an electric vehicle (EV), the current detection circuit 103 supplies an interruption signal to the switch 102, turning the switch 102 on (ON), thereby supplying a fusing current from the auxiliary power supply 101 to the first fuse element section 2.

[0043] Here, the fusing current is a current large enough to fuse the first fuse element 7. On the other hand, the fusing current is a current smaller than the rated current flowing through the second fuse element portion 3.

[0044] In the protection element 1A of this embodiment, as shown in FIG. 4, when a fusing current is supplied to the first fuse element portion 2, the fusing current flows through the first fuse element 7, causing the first fuse element 7 to fuse, and an arc discharge occurs within the first space 12a.

[0045] At this time, a portion of the blown first fuse element 7 vaporizes, and the gas (e.g., air) in the first space 12a expands, causing the pressure in the first space 12a to increase. Furthermore, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10A.

[0046] As a result, the tip of cutting portion 14a physically cuts second fuse element 10A. After cutting portion 14a cuts second fuse element 10A, cutting portion 14a shields the cut portion of second fuse element 10A within cutting space 13.

[0047] As a result, in the protection circuit 100, the power supply from the main power supply 104 to the load circuit 105 is completely cut off.

[0048] In addition, in the protection element 1A of this embodiment, when an overcurrent flows through the second fuse element part 3, which is the main fuse, the overcurrent causes the second fuse element 10A to melt, thereby cutting off the power supply from the main power source 104 to the load circuit 105.

[0049] As described above, the protection device 1A of this embodiment can handle high voltages and large currents, and can achieve both the cutoff of overcurrent and the cutoff function in response to a cutoff signal.

[0050] (Second embodiment) Next, a protection element 1B shown in FIGS. 5 and 6 will be described as a second embodiment of the present invention. Fig. 5 is a cross-sectional view showing the configuration of protection element 1B. Fig. 6 is a cross-sectional view showing a state in which the current of protection element 1B is interrupted. In the following explanation, the same parts as those of protection element 1A will not be described and will be denoted by the same reference numerals in the drawings.

[0051] The protection element 1B of this embodiment has basically the same configuration as the protection element 1A, except that it includes a second fuse element 10B as shown in FIG. 5, for example, instead of the second fuse element 10A.

[0052] Specifically, the second fuse element 10B has a structure in which a plurality of conductive members 21 are stacked with insulating members 22 interposed therebetween. In this embodiment, two conductive members 21 are sandwiched between each of three insulating members 22.

[0053] The conductive member 21 is made of the same connecting conductor as the material exemplified for the second fuse element 10 A. The two conductive members 21 are attached to one surface (the upper surface in this embodiment) and the other surface (the lower surface in this embodiment) of the third terminal 9 a and the fourth terminal 9 b, respectively, by welding, soldering, or the like, while connecting one end of the third terminal 9 a to one end of the fourth terminal 9 b.

[0054] The insulating member 22 is preferably formed of an insulating material having a tracking resistance index CTI (resistance to tracking (carbonized conductive path) breakdown) of 500 V or more, similar to the above-described insulating casing 4 and insulating cover 5. Specifically, for example, nylon-based, Teflon-based, or other insulating materials can be used.

[0055] Each insulating member 22 is provided with a gap 22a corresponding to the cutting space 13. That is, this gap 22a is formed by removing a part of each insulating member 22 corresponding to the cutting space 13.

[0056] The cutting portion 14a extends from the second space 12b toward the cutting space 13, and its tip is inserted into the gap portion 22a (cutting space 13).

[0057] The protection element 1B of this embodiment having the above-described configuration is suitably used in the protection circuit 100, similar to the protection element 1A.

[0058] Therefore, in the protection element 1B of this embodiment, as shown in Figure 6, when a fusing current is supplied to the first fuse element section 2 by an interruption signal, the fusing current flows through the first fuse element 7, causing the first fuse element 7 to fuse, and an arc discharge occurs within the first space 12a.

[0059] At this time, a portion of the blown first fuse element 7 vaporizes, and the gas (e.g., air) in the first space 12a expands, causing the pressure in the first space 12a to increase. Furthermore, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10B.

[0060] As a result, the tip of cutting portion 14a physically cuts each conductive member 21 of second fuse element 10B. After cutting portion 14a cuts each conductive member 21 of second fuse element 10B, cutting portion 14a shields the cut portion of second fuse element 10B within gap 22a (cutting space 13).

[0061] As a result, in the protection circuit 100, the power supply from the main power supply 104 to the load circuit 105 is completely cut off.

[0062] As described above, the protection device 1B of this embodiment can handle high voltages and large currents, and can achieve both the cutoff of overcurrent and the cutoff function in response to a cutoff signal.

[0063] Furthermore, in the protection element 1B of this embodiment, by configuring the above-mentioned second fuse element 10B with a plurality of conductive members 21, it is possible to increase the rated current flowing through the second fuse element 10B compared to the above-mentioned second fuse element 10A.

[0064] (Third embodiment) Next, a protection element 1C shown in FIG. 7 will be described as a third embodiment of the present invention. 7 is a cross-sectional view showing the configuration of the protection element 1C. In the following description, the same parts as those in the protection elements 1A and 1B will not be described and will be denoted by the same reference numerals in the drawings.

[0065] The protection element 1C of this embodiment has basically the same configuration as the protection elements 1A and 1B, except that it includes a second fuse element 10C as shown in FIG. 7, for example, instead of the second fuse elements 10A and 10B.

[0066] Specifically, the second fuse element 10C has a structure in which a plurality of conductive members 21 are stacked with insulating members 22 interposed therebetween. In this embodiment, one insulating member 22 is sandwiched between two conductive members 21.

[0067] The protection element 1C of this embodiment having the above-described configuration is suitably used in the protection circuit 100, similar to the protection elements 1A and 1B.

[0068] Therefore, in the protection element 1C of this embodiment, although not shown in the figure, when a fusing current is supplied to the first fuse element portion 2 by an interruption signal, the fusing current flows through the first fuse element 7, causing the first fuse element 7 to fuse, and an arc discharge occurs within the first space 12a.

[0069] At this time, a portion of the blown first fuse element 7 vaporizes, and the gas (e.g., air) in the first space 12a expands, causing the pressure in the first space 12a to increase. Furthermore, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10C.

[0070] As a result, the tip of cutting portion 14a physically cuts each conductive member 21 of second fuse element 10C. After cutting portion 14a cuts each conductive member 21 of second fuse element 10C, cutting portion 14a shields the cut portion of second fuse element 10C within gap 22a (cutting space 13).

[0071] As a result, in the protection circuit 100, the power supply from the main power supply 104 to the load circuit 105 is completely cut off.

[0072] As described above, the protection device 1C of this embodiment can handle high voltages and large currents, and can achieve both the cutoff of overcurrent and the cutoff function in response to a cutoff signal.

[0073] Furthermore, in the protection element 1C of this embodiment, by configuring the above-mentioned second fuse element 10C with a plurality of conductive members 21, it is possible to increase the rated current flowing through the second fuse element 10C compared to the above-mentioned second fuse element 10A.

[0074] (Fourth embodiment) Next, a protection element 1D shown in FIG. 8 will be described as a fourth embodiment of the present invention. 8 is a cross-sectional view showing the configuration of the protection element 1D. In the following description, the same parts as those in the protection elements 1A and 1B will not be described and will be denoted by the same reference numerals in the drawings.

[0075] The protection element 1D of this embodiment has basically the same configuration as the protection elements 1A and 1B, except that it includes a second fuse element 10D as shown in FIG. 8, for example, instead of the second fuse elements 10A and 10B.

[0076] Specifically, the second fuse element 10D has a structure in which a plurality of conductive members 21 are stacked with insulating members 22 interposed therebetween. In this embodiment, four conductive members 21 are sandwiched between five insulating members 22.

[0077] The four conductive members 21 are attached by welding, soldering, etc. to one surface (top surface in this embodiment) and the other surface (bottom surface in this embodiment) of the third terminal 9a and the fourth terminal 9b, respectively, with one end of the third terminal 9a and one end of the fourth terminal 9b connected to each other.

[0078] The protection element 1D of this embodiment having the above-described configuration is suitably used in the protection circuit 100, similar to the protection elements 1A and 1B.

[0079] Therefore, in the protection element 1D of this embodiment, although not shown in the figure, when a fusing current is supplied to the first fuse element section 2 by an interruption signal, the fusing current flows through the first fuse element 7, causing the first fuse element 7 to fuse, and an arc discharge occurs within the first space 12a.

[0080] At this time, a portion of the blown first fuse element 7 vaporizes, and the gas (e.g., air) in the first space 12a expands, causing the pressure in the first space 12a to increase. Furthermore, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10D.

[0081] As a result, the tip of cutting portion 14a physically cuts each conductive member 21 of second fuse element 10D. After cutting portion 14a cuts each conductive member 21 of second fuse element 10D, cutting portion 14a shields the cut portion of second fuse element 10D within gap 22a (cutting space 13).

[0082] As a result, in the protection circuit 100, the power supply from the main power supply 104 to the load circuit 105 is completely cut off.

[0083] As described above, the protection device 1D of this embodiment can handle high voltages and large currents, and can achieve both the cutoff of overcurrent and the cutoff function in response to a cutoff signal.

[0084] Furthermore, in the protection element 1D of this embodiment, by configuring the above-mentioned second fuse element 10D with a plurality of conductive members 21, it is possible to increase the rated current flowing through the second fuse element 10D compared to the above-mentioned second fuse element 10A.

[0085] Furthermore, the second fuse element 10D may omit the top and bottom insulating members 22, and sandwich the top and bottom conductive members 21 between the second case 4b and the third case 4c, as in the second fuse element 10C of the third embodiment described above.

[0086] (Fifth embodiment) Next, a protection element 1E shown in FIGS. 9(A) and 9(B) will be described as a fifth embodiment of the present invention. 9A is a perspective view showing an example of the configuration of the protection element 1E. FIG. 9B is a perspective view showing another example of the configuration of the protection element 1E. In the following description, the same parts as those in the protection elements 1A to 1D will not be described and will be denoted by the same reference numerals in the drawings.

[0087] The protection element 1E of this embodiment has basically the same configuration as the protection elements 1A to 1D, except that, among the configurations of the protection elements 1A to 1D, lead terminals 23 such as those shown in Figures 9(A) and (B) are used as the first terminals 6a and the second terminals 6b.

[0088] Specifically, this lead terminal 23 is made of an electric wire coated with insulating resin, and is connected to both ends of the first fuse element 7, and is pulled out from both axial ends of the insulating casing 4 shown in Figure 9(A) or one axial end of the insulating casing 4 shown in Figure 9(B).

[0089] The protection element 1E of this embodiment having the above-described configuration is suitably used in the protection circuit 100, similar to the protection elements 1A to 1D.

[0090] Therefore, the protection device 1E of this embodiment can handle high voltages and large currents, and can achieve both the cutoff of overcurrent and the cutoff function in response to a cutoff signal.

[0091] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the fusing space 12 and the slider 14 are not necessarily limited to the shapes described above, and may have any shape that allows the slider 14 to move freely within the fusing space 12. Furthermore, the cutting space 13 and the cutting portion 14a are not necessarily limited to the shapes described above, and may have any shape that allows the tip of the cutting portion 14a to physically cut the second fuse elements 10A-10E. [Explanation of symbols]

[0092] 1A to 1E...protective element 2...first fuse element section 3...second fuse element section 4...insulating housing 5...insulating cover 6a...first terminal 6b...second terminal 7...first fuse element 8...terminal hole 9a...third terminal 9b...fourth terminal 10A to 10D...second fuse element 11...terminal hole 12...melting space 12a...first space 12b...second space 13...cutting space 14...slider 14a...cutting section 21...conductive member 22...insulating member 23...lead terminal 100...protective circuit

Claims

1. a first fuse element portion having a first terminal and a second terminal, and a first fuse element electrically connecting the first terminal and the second terminal; a second fuse element portion having a third terminal and a fourth terminal, and a second fuse element electrically connecting the third terminal and the fourth terminal; an insulating casing having a fusing space in which the first fuse element is located and a cutting space in which the second fuse element is located, and electrically insulating the first fuse element portion from the second fuse element portion while holding the first fuse element portion and the second fuse element portion; a slider located between the first fuse element and the second fuse element, the slider being arranged to be movable toward the second fuse element within the fusing space; the fusing space is divided into a first space in which the first fuse element is located across the slider, and a second space connected to the cutting space; the slider has a cutting portion protruding from the second space toward the cutting space, a protection element characterized in that, when a fusing current flows through the first fuse element and the first fuse element melts, an arc discharge occurs in the first space, and as the pressure in the first space increases, the slider moves toward the second fuse element, and the cutting portion cuts off the second fuse element.

2. 2. The protection element according to claim 1, wherein after the cutting portion cuts the second fuse element, the cutting portion shields the cut portion of the second fuse element within the cutting space.

3. the second fuse element has a structure in which a plurality of conductive members are stacked with insulating members interposed therebetween, 3. The protection element according to claim 1, wherein the insulating member has a gap corresponding to the cutting space.

4. 4. The protection element according to claim 1, further comprising a cylindrical insulating cover that houses the insulating casing therein.

5. 5. The protection element according to claim 1, wherein the melting point of the second fuse element is higher than the melting point of the first fuse element.

Images