Protection element

Abstract

In the protective element (1A), the fusing space (12) is divided into a first space (12a) where the first fuse element (7) is located and a second space (12b) connected to the cutting space (13) by the slider (14). The slider (14) has a cutting portion (14a) protruding from the second space (12b) toward the cutting space (13). When the first fuse element (7) melts due to the flow of fusing current in the first fuse element (7), an arc discharge is generated in the first space (12a). As the pressure in the first space (12a) rises, the slider (14) moves toward the second fuse element (10A), and the cutting portion (14a) cuts off the second fuse element (10A).

Description

Protective components This invention relates to a protective element. This application claims priority based on Japanese Patent Application No. 2022-022951, filed on February 17, 2022, the contents of which are incorporated herein by reference. Previously, there were fuse elements that would overheat and melt when the current exceeded the rated current, thus breaking the current path. Protective components incorporating fuse elements (fuse elements) are used, for example, in battery packs that use lithium-ion secondary batteries. In recent years, lithium-ion rechargeable batteries have been used not only in mobile devices but also in a wide range of fields such as electric vehicles and storage batteries. Therefore, there is a growing trend towards increasing the capacity of lithium-ion rechargeable batteries. Consequently, there is a demand for high-capacity lithium-ion batteries and protective components for battery packs with high-voltage and high-current paths. As a protective element for high voltage and high current (e.g., 100 V / 100 A or more), a trigger-type fuse, such as a pyro fuse, is used instead of a fusible fuse (see, for example, Patent Document 1 below). Prior Art Documents Patent Documents Patent Document 1: Japanese Patent No. 6433518 [The problem the invention aims to solve] However, with the aforementioned protective components becoming high-voltage and high-current, the housing size increases and material costs rise, resulting in high-cost current fuses. Furthermore, current high-voltage and high-current protective components only interrupt overcurrent and cannot simultaneously interrupt the signal interruption function. This invention is proposed in view of the aforementioned situation, and its object is to provide a protection element capable of handling high voltage and high current, and simultaneously realizing the functions of overcurrent interruption and interruption signal interruption. [Technical Means for Solving the Problem] To achieve the above objectives, the present invention provides the following means. [1] A protective element, characterized in that it comprises: 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 housing having a fusing space where the first fuse element is located and a cutting space where the second fuse element is located, and holding the first fuse element portion and the second fuse element portion together, and electrically insulating the first fuse element portion and the second fuse element portion from each other; and a slider located between the first fuse element and the second fuse element, and movable within the fusing space toward the second fuse element; the fusing space is divided by the slider into a first space where the first fuse element is located and a second space connected to the cutting space. The aforementioned slider has a cutting portion protruding from the aforementioned second space toward the aforementioned cutting space. When the aforementioned first fuse element melts due to the flow of fusing current, an arc discharge is generated in the aforementioned first space. As the pressure in the aforementioned first space increases, the aforementioned slider moves toward the aforementioned second fuse element, and the aforementioned cutting portion cuts the aforementioned second fuse element. [2] As described in [1], after the aforementioned cutting portion cuts the aforementioned second fuse element, the cutting portion of the aforementioned second fuse element is shielded by the aforementioned cutting portion in the aforementioned cutting space. [3] As described in [1] or [2], the aforementioned second fuse element has a structure in which a plurality of conductive members are stacked in layers with insulating members, and a gap corresponding to the aforementioned cutting space is provided in the aforementioned insulating member. [4] As described in any one of [1] to [3], the aforementioned protective element has a cylindrical insulating outer cover that houses the aforementioned insulating housing inside. [5] As described in any of [1] to [4] above, the melting point of the second fuse element is higher than that of the first fuse element. [Effects of the Invention] As described above, according to the present invention, a protection element is provided that can cope with high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Furthermore, in the drawings used in the following description, for ease of understanding, sometimes the parts that are to be considered features are represented in a stylized manner, and the dimensions and ratios of the constituent elements are not limited to the actual dimensions. Also, the materials, dimensions, etc., exemplified in the following description are examples, and the present invention is not necessarily limited to them; it can be implemented with appropriate modifications without changing its essence. (First Embodiment) First, as a first embodiment of the present invention, the protection element 1A shown in Figures 1 to 4 will be described, for example. Furthermore, Figure 1 is a perspective view showing the appearance of the protection element 1A. Figure 2 is a cross-sectional view showing the configuration of the protection element 1A. Figure 3 is a circuit diagram showing an example configuration of a protection circuit 100 using the protection element 1A. Figure 4 is a cross-sectional view showing the state in which the current to the protection element 1A is interrupted. As shown in Figures 1 and 2, the protective element 1A of this embodiment includes: 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 and electrically insulates the first fuse element portion 2 and the second fuse element portion 3 from each other, and an insulating outer cover 5 that houses the insulating housing 4 inside. The first fuse element 2 has a first terminal 6a and a second terminal 6b, and a first fuse element 7 electrically connecting the first terminal 6a and the second terminal 6b. The first terminal 6a and the second terminal 6b are made of a metal material such as copper (Cu) and are formed into a generally rectangular flat plate. The first terminal 6a and the second terminal 6b are arranged side by side in a straight line on the same plane with one end facing each other (the inner side of the first fuse element part 2). Furthermore, on the other end side (outside the first fuse element part 2) of the first terminal 6a and the second terminal 6b, terminal holes 8 for external connection are provided in a circular shape. The first fuse element 7 is a fusible conductor, for example, comprising a metal material such as a copper (Cu), silver (Ag), tin (Sn) alloy, lead (Pb) alloy, or a laminate of tin (Sn) alloy and silver (Ag), and is formed into a generally rectangular flat plate shape. The first fuse element 7 is mounted on one side (the lower surface in this embodiment) of the first terminal 6a and the second terminal 6b by means of welding or fusion, in a state that connects one end of the first terminal 6a and one end of the second terminal 6b. The second fuse element 3 has a third terminal 9a and a fourth terminal 9b, and a second fuse element 10A that electrically connects the third terminal 9a and the fourth terminal 9b. The third terminal 9a and the fourth terminal 9b are made of the same material as those illustrated in the first terminal 6a and the second terminal 6b above, and are formed into a generally rectangular flat plate shape. The third terminal 9a and the fourth terminal 9b are arranged side by side in a straight line on the same plane with one end facing each other (the inner side of the second fuse element part 3). Furthermore, on the other side of the third terminal 9a and the fourth terminal 9b (outside the second fuse element part 3), terminal holes 11 for external connection are provided in a circular shape. The second fuse element 10A serves as a connecting conductor and, for example, comprises a metal material such as a copper (Cu), silver (Ag), tin (Sn) alloy, or lead (Pb) alloy, and is formed into a generally rectangular flat plate shape. Furthermore, the second fuse element 10A uses a material with a higher melting point than the first fuse element 7. For example, in this embodiment, the first fuse element 7 uses a tin (Sn) alloy and silver (Ag) laminate, and the second fuse element 10A uses copper (Cu), which has a higher melting point than the first fuse element 7. The second fuse element 10A is mounted on one side (the upper surface in this embodiment) of the third terminal 9a and the fourth terminal 9b by means of welding or fusion, in a state that connects one end of the third terminal 9a and one end of the fourth terminal 9b. The insulating housing 4 has a first housing 4a, a second housing 4b, and a third housing 4c, each containing the insulating material described below, and is integrally formed into an elongated cylindrical shape. Furthermore, the insulating housing 4 is not necessarily limited to this shape and can be modified appropriately. Furthermore, the insulating housing 4 is constructed by combining the first housing 4a, the second housing 4b and the third housing 4c into one unit, with the first fuse element 2 sandwiched between the first housing 4a and the second housing 4b, and the second fuse element 3 sandwiched between the second housing 4b and the third housing 4c. In this way, the insulating housing 4 maintains the first fuse element 2 and the second fuse element 3 in a state where the other ends of the first terminal 6a and the second terminal 6b are exposed to the outside from both ends in the axial direction, and the other ends of the third terminal 9a and the fourth terminal 9b, and electrically insulates the first fuse element 2 and the second fuse element 3 from each other. Inside the insulating housing 4, a fusing space 12 is provided where the first fuse element 7 is located, and a cutting space 13 is provided where the second fuse element 10A is located. Furthermore, a slider 14 is disposed in the fusing space 12. The fusing space 12 is further divided by the slider 14 into a first space 12a where the first fuse element 7 is located, and a second space 12b connected to the cutting space 13. The fusible space 12 extends between the first housing 4a and the second housing 4b, located in the middle of the first fuse element 7, forming a space orthogonal to the axis of the insulating housing 4. While the shape of the fusible space 12 is not particularly limited, examples include cylindrical or cuboid shapes. The cutting space 13 extends between the second housing 4b and the third housing 4c, located in the middle of the second fuse element 10A, forming a slit-like space orthogonal to the axial direction of the insulating housing 4. Furthermore, the location of the cutting space 13 is not limited to the middle of the second fuse element 10A; for example, it can be located towards the third terminal 9a. On the other hand, the slider 14 may contain insulating materials such as nylon, Teflon (registered trademark), or LCP, and be formed into a plate thinner than the fusion space 12. Furthermore, the slider 14 may also be made of metal with an insulating treatment on its surface. Specifically, for example, an aluminum alloy material with an aluminum oxide film treatment on its surface can be used. The slider 14 is located between the first fuse element 7 (first space 12a) and the second fuse element 10A (second space 12b) in the fuse space 12, and is disposed within the fuse space 12. In this way, the slider 14 is freely movable within the fuse space 12 toward the side of the second fuse element 10A (the lower side in this embodiment). Furthermore, the slider 14 has a rectangular flat cutting portion 14a protruding from the surface (lower surface in this embodiment) opposite to the second space 12b. The cutting portion 14a extends from the second space 12b toward the cutting space 13, and its front end is inserted into the cutting space 13, thereby abutting against the second fuse element 10A. The insulating cover 5 comprises the insulating material described below and has a shape that covers the entire circumference of the outer circumference of the insulating housing 4. By seamlessly covering the entire circumference of the insulating housing 4, the insulating cover 5 can prevent damage to the insulating housing 4 from arc discharge when the first fuse element 7 blows. Furthermore, the insulating housing 4 and the insulating outer cover 5 are preferably made of an insulating material with a tracking resistance index (CTI) of 500 V or higher. Moreover, the tracking resistance index (CTI) can be determined by testing based on IEC 60112. Specifically, the insulating material for the insulating housing 4 and the insulating outer cover 5 is preferably a resin material with a smaller heat capacity and a lower melting point than ceramic materials. Furthermore, the resin material has the characteristic of reducing arc discharge caused by vaporization cooling (erosion), or of making it difficult to form conductive channels when molten metal particles from the first fuse element 7 adhere to the insulating housing 4 due to surface deformation of the insulating outer cover 5 or the aggregation of the deposits. As specific resin materials, for example, polyamine resins or fluorinated resins can be used. Polyamine resins can be aliphatic polyamines or semi-aromatic polyamines. Examples of aliphatic polyamides include nylon 4, nylon 6, nylon 46, and nylon 66. Examples of semi-aromatic polyamides include nylon 6T, nylon 9T, and polyphthalamide (PPA) resin. Examples of fluoropolymers include polytetrafluoroethylene. Furthermore, polyamide and fluoropolymer resins generally have high heat resistance and are not easily flammable. In particular, aliphatic polyamide does not readily produce graphite even when burned. Therefore, by using aliphatic polyamide to form the insulating shell 4 and the insulating cover 5, it is possible to more reliably prevent the formation of new current paths by graphite generated during the arc discharge when the first fuse element 7 melts. The protection element 1A of this embodiment, having the configuration described above, is preferably used, for example, in the protection circuit 100 shown in FIG3. Specifically, in this protection circuit 100, an auxiliary power supply 101 is connected to one end of the first fuse element section 2, which 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. On the other hand, in the protection circuit 100, a main power supply 104 is connected to one end of the second fuse element part 3, which serves as the main fuse, and a load circuit 105 is connected to the other end of the second fuse element part 3. In the protection circuit 100, for example, when the current detection circuit 103 detects an abnormality caused by damage to the equipment equipped with the main power supply, such as an accident involving an electric vehicle (EV), the current detection circuit 103 supplies a cut-off signal to the switch 102, causing the switch 102 to be turned on, thereby supplying fusing current from the auxiliary power supply 101 to the first fuse element 2. Here, the fusing current is sufficient to melt the first fuse element 7. On the other hand, the fusing current is smaller than the rated current flowing in the second fuse element section 3. In the protection element 1A of this embodiment, as shown in FIG4, when a fusing current is supplied to the first fuse element 2, the fusing current flows in the first fuse element 7 and the first fuse element 7 melts, generating an arc discharge in the first space 12a. At this time, a portion of the first fuse element 7 that has blown vaporizes, and the gas (e.g., air) in the first space 12a expands, thereby increasing the pressure in the first space 12a. Subsequently, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10A. In this way, the front end of the cutting section 14a physically cuts off the second fuse element 10A. Furthermore, after the cutting section 14a cuts off the second fuse element 10A, the cut portion of the second fuse element 10A is covered by the cutting section 14a within the cutting space 13. As a result, in the protection circuit 100, the power supply from the self-powered power supply 104 to the load circuit 105 is completely cut off. Furthermore, in the protection element 1A of this embodiment, when an overcurrent flows in the second fuse element 3, which serves as the main fuse, the second fuse element 10A melts due to the overcurrent, and the power supply from the self-powered power supply 104 to the load circuit 105 is cut off. As described above, the protection element 1A in this embodiment can handle high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. (Second Embodiment) Next, as a second embodiment of the present invention, the protection element 1B shown in Figures 5 and 6 will be described for example. Figure 5 is a cross-sectional view showing the configuration of the protection element 1B. Figure 6 is a cross-sectional view showing the state in which the current of the protection element 1B is interrupted. Furthermore, in the following description, parts equivalent to those of the protection element 1A described above will be omitted from the description, and the same symbols will be used in the figures. In this embodiment, the protection element 1B replaces the second fuse element 10A described above. For example, it includes the second fuse element 10B as shown in FIG5, but otherwise has a configuration that is basically the same as that of the protection element 1A described above. Specifically, the second fuse element 10B has a structure in which a plurality of conductive members 21 are stacked together with insulating members 22. In this embodiment, it is arranged such that two conductive members 21 are sandwiched between each of the three insulating members 22. The conductive member 21 includes a connecting conductor made of the same material as that illustrated in the second fuse element 10A described above. The two conductive members 21 are respectively mounted on one side (the upper surface in this embodiment) and the other side (the lower surface in this embodiment) of the third terminal 9a and the fourth terminal 9b by means of welding or soldering, in a state that connects one end side of the third terminal 9a and one end side of the fourth terminal 9b. The insulating member 22, for example, is preferably made of an insulating material with a tracking resistance index (CTI) of 500 V or higher, similar to the insulating housing 4 and the insulating outer cover 5 described above. Specifically, insulating materials such as nylon and Teflon can be used. Furthermore, each insulating member 22 is provided with a gap 22a corresponding to the aforementioned cut-off space 13. That is, the gap 22a is formed by removing a portion of each insulating member 22 corresponding to the aforementioned cut-off space 13. The cutting portion 14a extends from the second space 12b toward the cutting space 13, and its front end is inserted into the gap portion 22a (cutting space 13). The front end of the cutting portion 14a may also abut against the conductive member 21 installed on one side (e.g., the upper surface) of the third terminal 9a and the fourth terminal 9b. The protection element 1B of this embodiment, having the configuration described above, is preferably used in the protection circuit 100 in the same manner as the protection element 1A described above. Therefore, in the protection element 1B of this embodiment, as shown in FIG6, when a fusing current is supplied to the first fuse element 2 by means of a blocking signal, the fusing current flows in the first fuse element 7 and the first fuse element 7 melts, generating an arc discharge in the first space 12a. At this time, a portion of the first fuse element 7 that has blown vaporizes, and the gas (e.g., air) in the first space 12a expands, thereby increasing the pressure in the first space 12a. Consequently, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10B. In this way, the front end of the cutting section 14a physically cuts off each conductive member 21 of the second fuse element 10B. Furthermore, after the cutting section 14a cuts off each conductive member 21 of the second fuse element 10B, the cut portion of the second fuse element 10B is covered by the cutting section 14a in the gap 22a (cutting space 13). As a result, in the protection circuit 100, the power supply from the self-powered power supply 104 to the load circuit 105 is completely cut off. As described above, the protection element 1B in this embodiment can handle high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. Furthermore, in the protection element 1B of this embodiment, the second fuse element 10B is constructed by using a plurality of conductive members 21, which can increase the rated current flowing in the second fuse element 10B compared to the second fuse element 10A. (Third Embodiment) Next, as a third embodiment of the present invention, the protective element 1C shown in FIG7 will be described for example. Furthermore, FIG7 is a cross-sectional view showing the configuration of the protective element 1C. In the following description, the parts that are equivalent to the protective elements 1A and 1B described above will be omitted from the description, and the same symbols will be used in the drawings. In this embodiment, the protection element 1C replaces the second fuse elements 10A and 10B described above. For example, it includes the second fuse element 10C shown in FIG7, but otherwise has a configuration that is basically the same as the protection elements 1A and 1B described above. Specifically, the second fuse element 10C has a structure in which a plurality of conductive members 21 are stacked with insulating members 22. In this embodiment, it is configured such that one insulating member 22 is sandwiched between two conductive members 21. The protection element 1C of this embodiment, having the configuration described above, is preferably used in the protection circuit 100 in the same manner as the protection elements 1A and 1B described above. Therefore, although the illustration is omitted in the protection element 1C of this embodiment, when the fusing current is supplied to the first fuse element 2 by means of the interruption signal, the fusing current flows in the first fuse element 7 and the first fuse element 7 melts, generating an arc discharge in the first space 12a. At this time, a portion of the first fuse element 7 that has blown vaporizes, and the gas (e.g., air) in the first space 12a expands, thereby increasing the pressure in the first space 12a. Consequently, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10C. In this way, the front end of the cutting section 14a physically cuts off each conductive member 21 of the second fuse element 10C. Furthermore, after the cutting section 14a cuts off each conductive member 21 of the second fuse element 10C, the cut portion of the second fuse element 10C is covered by the cutting section 14a in the gap 22a (cutting space 13). As a result, in the protection circuit 100, the power supply from the self-powered power supply 104 to the load circuit 105 is completely cut off. As described above, the protection element 1C in this embodiment can handle high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. Furthermore, in the protection element 1C of this embodiment, the second fuse element 10C is constructed by using a plurality of conductive members 21, which can increase the rated current flowing in the second fuse element 10C compared to the second fuse element 10A. (Fourth Embodiment) Next, as a fourth embodiment of the present invention, the protective element 1D shown in FIG8 will be described for example. Furthermore, FIG8 is a cross-sectional view showing the configuration of the protective element 1D. In the following description, the parts that are equivalent to the protective elements 1A and 1B described above will be omitted from the description, and the same symbols will be used in the drawings. In this embodiment, the protection element 1D replaces the second fuse elements 10A and 10B described above. For example, it includes the second fuse element 10D as shown in FIG8, but otherwise has a configuration that is basically the same as the protection elements 1A and 1B described above. Specifically, the second fuse element 10D has a structure in which a plurality of conductive members 21 are stacked between insulating members 22. In this embodiment, it is arranged such that four conductive members 21 are sandwiched between each of the five insulating members 22. Four conductive members 21 are installed on one side (the upper surface in this embodiment) and the other side (the lower surface in this embodiment) of the third terminal 9a and the fourth terminal 9b respectively, by means of fusion or welding, in a state where one end of the third terminal 9a and the fourth terminal 9b are respectively connected. The protection element 1D of this embodiment, having the configuration described above, can be appropriately used in the protection circuit 100 in the same way as the protection elements 1A and 1B described above. Therefore, although the illustration is omitted in the protection element 1D of this embodiment, when the fusing current is supplied to the first fuse element 2 by means of the interruption signal, the fusing current flows in the first fuse element 7 and the first fuse element 7 melts, generating an arc discharge in the first space 12a. At this time, a portion of the first fuse element 7 that has blown vaporizes, and the gas (e.g., air) in the first space 12a expands, thereby increasing the pressure in the first space 12a. Subsequently, as the pressure in the first space 12a increases, the slider 14 moves toward the second fuse element 10D. In this way, the front end of the cutting section 14a physically cuts off each conductive member 21 of the second fuse element 10D. Furthermore, after the cutting section 14a cuts off each conductive member 21 of the second fuse element 10D, the cut portion of the second fuse element 10D is covered by the cutting section 14a in the gap 22a (cutting space 13). As a result, in the protection circuit 100, the power supply from the self-powered power supply 104 to the load circuit 105 is completely cut off. As described above, the protection element 1D in this embodiment can handle high voltage and high current, and can simultaneously realize the overcurrent blocking and the blocking function using the blocking signal. Furthermore, in the protection element 1D of this embodiment, the second fuse element 10D is constructed by using a plurality of conductive members 21, which can increase the rated current flowing in the second fuse element 10D compared to the second fuse element 10A. Furthermore, the second fuse element 10D can also omit the uppermost and lowermost insulating members 22, just like the second fuse element 10C in the third embodiment described above, and use the second housing 4b and the third housing 4c to sandwich the uppermost and lowermost conductive members 21. (Fifth Embodiment) Next, as a fifth embodiment of the present invention, the protective element 1E shown in Figures 9A and 9B will be described, for example. Furthermore, Figure 9A is a perspective view showing an example of the configuration of the protective element 1E. Figure 9B is a perspective view showing another example of the configuration of the protective element 1E. In the following description, parts equivalent to those of the protective elements 1A to 1D described above will be omitted from the description, and the same symbols will be used in the figures. The protective element 1E of this embodiment has a configuration that is basically the same as that of the protective elements 1A to 1D, except that, for example, the lead terminal 23 shown in FIG9A and FIG9B is used as the first terminal 6a and the second terminal 6b. Specifically, the lead terminal 23 includes an electrical wire coated with insulating resin, which is connected to both ends of the first fuse element 7, extending from either end of the insulating housing 4 along the axial direction shown in FIG9A, or from one end of the insulating housing 4 along the axial direction shown in FIG9B. The protection element 1E of this embodiment, having the configuration described above, is preferably used in the protection circuit 100 in the same manner as the protection elements 1A to 1D described above. Therefore, the protection element 1E in this embodiment can cope with high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the fusion-breaking space 12 and the slider 14 are not limited to the shapes described above, as long as the slider 14 can move freely within the fusion-breaking space 12. Also, the cutting space 13 and the cutting portion 14a are not limited to the shapes described above, as long as the cutting portion 14a can physically cut the second fuse elements 10A to 10E via its front end. [Industrial Applicability] According to the present invention, a protection element is provided that can cope with high voltage and high current, and can simultaneously realize the functions of overcurrent interruption and interruption signal interruption. 1A~1E: Protective element; 2: First fuse element section; 3: Second fuse element section; 4: Insulating housing; 4a: First housing; 4b: Second housing; 4c: Third housing; 5: Insulating cover; 6a: First terminal; 6b: Second terminal; 7: First fuse element; 8: Terminal hole; 9a: Third terminal; 9b: Fourth terminal; 10A~10D: Second fuse element; 11: Terminal hole; 12: Fusible space; 12a: First space; 12b: Second space; 13: Cut-off space; 14: Slider; 14a: Cut-off part; 21: Conductive member; 22: Insulating member; 22a: Gap part; 23: Lead terminal; 100: Protective circuit; 101: Auxiliary power supply; 102: Switch; 103: Current detection circuit; 104: Main power supply; 105: Load circuit. Figure 1 is a perspective view showing the appearance of the protective element according to the first embodiment of the present invention. Figure 2 is a cross-sectional view showing the configuration of the protective element shown in Figure 1. Figure 3 is a circuit diagram showing an example of a protective circuit using the protective element shown in Figure 1. Figure 4 is a cross-sectional view showing the state in which the current of the protective element shown in Figure 2 is interrupted. Figure 5 is a cross-sectional view showing the configuration of the protective element according to the second embodiment of the present invention. Figure 6 is a cross-sectional view showing the state in which the current of the protective element shown in Figure 5 is interrupted. Figure 7 is a cross-sectional view showing the configuration of the protective element according to the third embodiment of the present invention. Figure 8 is a cross-sectional view showing the configuration of the protective element according to the fourth embodiment of the present invention. Figure 9A is a perspective view showing an example of the configuration of the protective element according to the fifth embodiment of the present invention. Figure 9B is a perspective view showing another example of the configuration of the protective element according to the fifth embodiment of the present invention. 1A: Protective Component 2: First Fuse Element Section 3: Second Fuse Element Section 4: Insulating housing 4a: 1st box 4b: Box 2 4c: Box 3 5: Insulating outer cover 6a: Terminal 1 6b: Terminal 2 7: First Fuse Element 8: Terminal hole 9a: Terminal 3 9b: Terminal 4 10A: Second Fuse Element 11: Terminal hole 12: Circuit Breaker Space 12a: First Space 12b: Second Space 13: Cut off space 14: Sliding parts 14a: Cut-off section

Claims

1. A protective element, characterized by comprising: 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 housing having a fusing space where the first fuse element is located and a cutting space where the second fuse element is located, holding the first fuse element portion and the second fuse element portion together and electrically insulating them from each other; and a slider located between the first fuse element and the second fuse element, and movable within the fusing space toward the second fuse element; the fusing space being divided by the slider into a first space where the first fuse element is located and a second space connected to the cutting space. The aforementioned slider has a cutting portion protruding from the aforementioned second space toward the aforementioned cutting space. When the first fuse element melts due to the flow of fusing current in the aforementioned first fuse element, an arc discharge is generated in the aforementioned first space. As the pressure in the aforementioned first space increases, the aforementioned slider moves toward the aforementioned second fuse element, and the aforementioned cutting portion cuts off the aforementioned second fuse element.

2. The protective element of claim 1, wherein after the second fuse element is cut off by the cutting portion, the cutting portion of the second fuse element is covered by the cutting portion within the cutting space.

3. The protective element as claimed in claim 1 or 2, wherein the second fuse element has a structure in which a plurality of conductive members are stacked in layers through insulating members, and a gap corresponding to the cut-off space is provided in the insulating member.

4. The protective element of claim 1 or 2 has a cylindrical insulating cover that houses the aforementioned insulating housing inside.

5. The protective element as claimed in claim 1 or 2, wherein the melting point of the second fuse element is higher than the melting point of the first fuse element.

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