Excitation fuse auxiliary arc extinguishing structure

Abstract

An auxiliary arc extinguishing structure for an excitation fuse includes an upper shell and a lower shell, and a conductive plate arranged between the upper shell and the lower shell; an electronic ignition explosion device and a piston are arranged from top to bottom in the accommodating cavity of the upper shell; an accommodating cavity for the conductive plate to fall after being disconnected is arranged on the lower shell; it is characterized in that an auxiliary arc extinguishing device is arranged on the piston, the conductive plate or the bottom of the accommodating cavity of the lower shell alone or at least two parts at the same time. The auxiliary arc extinguishing structure can improve the breaking capacity of the excitation fuse and improve the working reliability.

Description

Technical Field

[0001] The invention relates to the fields of power control and electric vehicles, and in particular to an auxiliary arc extinguishing structure of an excitation fuse for cutting off a current transmission circuit through external signal control. Background Art

[0002] Circuit overcurrent protection products are based on fuses that melt due to the heat generated by the current flowing through the fuse. The main problem is the matching relationship between the thermal fuse and the load. For example, in the protection of the main circuit of new energy vehicles, if the load is overloaded or short-circuited by a small multiple, the selection of a low-current fuse cannot meet the short-time current overshoot situation, and if a high-current fuse is selected, it cannot meet the requirements of fast protection. In the lithium battery pack that currently provides energy for new energy vehicles, the output current is about several times the rated current in the case of a short circuit. The fuse protection time cannot meet the requirements, causing the battery pack to heat up and catch fire. Since the heating of the withstand current and the heating and melting of the breaking current are both derived from the current flowing through the fuse, this type of protection device that uses the heating and melting of the current cannot achieve a sufficiently fast breaking speed for a certain amplitude fault current under the conditions of having a large rated current or withstanding a strong short-term overload / impact current (such as a short-term large current when the electric vehicle starts or climbs), or achieve a higher rated current under the conditions of a sufficiently fast protection speed for a certain amplitude fault current, or withstand a large overload / impact current without damage.

[0003] Another problem with thermal cutoffs is that they cannot communicate with external devices and cannot be triggered by signals other than current, such as the vehicle ECU, BMS, or other sensors. If the vehicle is severely collided, soaked in water, or the battery temperature is too high after exposure to the sun, and the circuit cannot be cut off in time, it may cause the battery pack to burn and eventually damage the vehicle.

[0004] At present, there is a fast-breaking cut-off opening structure on the market, which mainly includes a gas generating device, a conductive plate and a receiving chamber after the conductive plate falls. The gas generating device generates high-pressure gas to drive the piston to break the conductive plate. After breaking, the conductive plate falls down into the receiving chamber to achieve the purpose of rapid circuit disconnection. However, it still has some shortcomings and defects, resulting in limited arc extinguishing ability: it is difficult to interrupt large fault currents due to air restrictions; the arc is directly cooled by air, and the breaking ability is greatly affected by air pressure and temperature and humidity; during the breaking process, the arc directly burns the piston knife, and the burning of the piston knife will affect the smooth arc extinguishing; during the breaking process, except for the limited disturbance of the arc by the piston knife, there is no other structure or mechanism to assist in arc extinguishing. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an auxiliary arc extinguishing device for an excitation fuse, which can more effectively extinguish a large number of arcs generated when the fuse is disconnected, thereby improving the breaking capacity and the electrical performance of the fuse.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is an auxiliary arc extinguishing structure of an excitation fuse, comprising an upper shell and a lower shell, and a conductive plate arranged between the upper shell and the lower shell; an electronic ignition explosion device and a piston are arranged from top to bottom in the accommodating cavity of the upper shell; a accommodating cavity for the conductive plate to fall after being disconnected is arranged on the lower shell; it is characterized in that an auxiliary arc extinguishing device is arranged separately or in combination of at least two at the bottom of the accommodating cavity of the piston, the conductive plate or the lower shell.

[0007] The piston comprises a piston body and a knife-shaped structure located below the piston body; the auxiliary arc extinguishing device is respectively arranged on the upper side of the piston body or on the two side surfaces of the knife-shaped structure in contact with the conductive plate.

[0008] The auxiliary arc extinguishing device arranged on the piston body is a magnetic north pole and a magnetic south pole arranged from top to bottom on the piston body; the magnetic north pole and the magnetic south pole can form a magnetic field that disturbs the arc, keeps the arc away, stretches and cools it.

[0009] The auxiliary arc extinguishing device on the knife-shaped structure is an arc-isolating sheet arranged on two sides of the knife-shaped structure.

[0010] A fracture notch is provided on the conductive plate, and the auxiliary arc extinguishing device is an arc extinguishing paint or colloid coated on the fracture notch.

[0011] An auxiliary arc extinguishing device is arranged on the conductive plate located at the accommodating cavity of the upper shell and the lower shell, and the auxiliary arc extinguishing device is an arc disturbing plate.

[0012] At least one layer of arc-suspension sheet is respectively arranged on the upper and lower sides of the conductive plate located in the accommodating cavities of the upper shell and the lower shell; one end of the arc-suspension sheet is firmly fixed on the conductive plate, and the other end is fixed on the conductive plate with a smaller bonding force.

[0013] The auxiliary arc extinguishing device is arranged at the bottom of the accommodating cavity on the lower shell; when the conductive plate is broken, the conductive plate that is rotated and disconnected along the fixed end can contact the auxiliary arc extinguishing device.

[0014] The auxiliary arc extinguishing device comprises an arc extinguishing liquid substance or an arc extinguishing solid substance arranged at the bottom of the accommodating cavity; the arc extinguishing liquid substance or the arc extinguishing solid substance is sealed at the bottom of the accommodating cavity through a sealing film.

[0015] The present invention provides auxiliary arc extinguishing devices in different parts alone or in combination, and performs auxiliary arc extinguishing by various technical means such as magnetic field magnetic blowing arc extinguishing, arc extinguishing material (arc extinguishing liquid or solid) arc extinguishing, arc isolation plate arc extinguishing, arc disturbing plate arc extinguishing, etc. The advantages of each auxiliary arc extinguishing device are: it can realize rapid arc extinguishing of large current; arc extinguishing liquid, solid, arc isolation plate, arc disturbing plate, etc. are not sensitive to air pressure and environmental temperature and humidity, which can improve arc extinguishing reliability; with arc isolation plate protection, the electric arc has almost no damage to the piston knife; the arc extinguishing process is safer. By providing an auxiliary arc extinguishing device, the breaking capacity of the excitation fuse can be improved, and the working reliability can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 , a schematic diagram of the cross-sectional structure of an excitation fuse provided with an arc isolation plate.

[0017] Figure 2 , schematic diagram of the cross-sectional structure of an excitation fuse with a magnetic field.

[0018] Figure 3 , a schematic diagram of the structure in which auxiliary arc-extinguishing coating or arc-extinguishing colloid is applied to the fracture notch of the conductive plate. Figure a is a schematic diagram of the structure before the conductive plate is disconnected, and Figure b is a schematic diagram of the structure after the conductive plate is disconnected.

[0019] Figure 4 , a schematic diagram of the structure of an auxiliary arc extinguishing device arranged at the bottom of the accommodating cavity of the lower shell. Figure a is a schematic diagram of the structure before the conductive plate is disconnected, and Figure b is a schematic diagram of the structure after the conductive plate is disconnected.

[0020] Figure 5 , a schematic diagram of the cross-sectional structure of an arc-suscepting plate arranged on a conductive plate.

[0021] Figure 6 , a schematic diagram of the structural relationship between the arc-suspension sheet and the conductive plate after the conductive plate is disconnected. Among them, Figures a, b, c, d, and e are schematic diagrams of the five installation methods of the arc-suspension sheet after the conductive plate is disconnected.

[0022] Figure 7 , a schematic diagram of the structure of installing an auxiliary arc extinguishing device on the piston, conductive plate, lower shell accommodating cavity and other parts of the excitation fuse. Figure a is a schematic diagram of the structure before the conductive plate is disconnected, and figure b is a schematic diagram of the structure after the conductive plate is disconnected. DETAILED DESCRIPTION

[0023] The fast current cutting device of the present invention mainly comprises an upper shell, a conductive plate, a lower shell, a gas generating device, etc. Figures 1 to 6 ,in.

[0024] The housing, in this embodiment, is composed of an upper housing 1 and a lower housing 2. A conductive plate 3 is provided between the contact surfaces of the upper housing and the lower housing, and the upper housing, the lower housing and the conductive plate are fixed together by screws. The conductive plate is sealed at the contact portion with the end surfaces of the upper housing and the lower housing.

[0025] A housing chamber is provided in the upper housing. In this embodiment, the housing chamber is divided into two parts, an upper part and an lower part, which are connected to each other. An electronic ignition explosion device 4 is fixedly provided in the upper housing chamber, and a pressure plate is provided at the upper end of the electronic ignition explosion device to position it. A piston 5 is provided in the lower housing chamber. The piston and the lower housing chamber are in an interference fit. The interference fit degree satisfies that when the piston is impacted by high-pressure gas, it can break away from the interference fit constraint and make an impact movement downward. The electronic ignition explosion device is a gas generating device, which generates high-pressure gas by receiving an external signal to ignite, thereby pushing the piston to move.

[0026] The piston 5 comprises a piston body of a cylindrical structure, and the piston body is interference-fitted with the lower accommodation chamber of the upper shell. A knife-shaped structure 51 is arranged below the piston body. The two side ends of the knife-shaped structure protrude outside the side wall of the piston body, and limiting protrusions protruding from the two side ends are arranged on the front and rear sides of the lower part of the two side ends of the knife-shaped structure protruding from the piston body. The width of the knife-shaped structure is greater than the width of the conductive plate, and it is located directly above the fracture notch of the conductive plate. The bottom of the knife-shaped structure is arranged with an inclined surface, which is convenient for concentrated application of shear force and convenient for cutting the conductive plate. Vertical grooves corresponding to the two side ends of the knife-shaped structure are opened on the wall of the lower accommodation chamber, and the vertical grooves extend downward to the lower end surface of the upper shell and are connected to the accommodation chamber of the lower shell. A notch for accommodating the limiting protrusion is also arranged in the groove. When the piston is arranged in the lower accommodation chamber, the two side ends of the knife-shaped structure are respectively located in the vertical grooves corresponding thereto, and the limiting protrusion is located in the notch. In this way, the vertical groove can position the piston to prevent it from rotating, ensuring that the knife-like structure can align with the desired cutting position of the conductive plate when impacting. The limiting protrusion is located in the notch to limit the upper and lower positions of the piston to prevent the piston from damaging the fracture notch of the conductive plate under vibration.

[0027] When the piston blade-like structure impacts the conductive plate, see Figure 1, arc-isolating plates 52 for auxiliary arc extinguishing are respectively arranged on the two side surfaces in contact with the conductive plate. The arc-isolating plates are fitted on the side of the knife-shaped structure. The arc-isolating plates are made of hard-to-melt materials such as ceramic plates or mica plates. Arc-extinguishing gas-producing materials can also be added to the side of the arc-isolating plates as needed. When the excitation fuse is triggered by an external trigger signal, the conductive plate breaks from the pre-break, and an arc is generated at the break. Arc-isolating plates are attached to both ends of the piston knife. The arc-isolating plates increase the arc spacing and cool the arc to extinguish, and the arc-extinguishing gas-producing materials added to the piston can be used to release arc-extinguishing gas for arc extinguishing. The advantage of arranging arc-isolating plates on the piston is that with the help of the arc-isolating plates on both sides of the piston knife, the arc of large current can be extinguished quickly; the arc-isolating plates are insensitive to air pressure and ambient temperature and humidity, which improves the reliability of arc extinguishing; with the protection of the arc-isolating plates, the arc has almost no damage to the piston knife; the arc extinguishing process is safer.

[0028] On the top of the piston body, see Figure 2 , two magnetic materials, a magnetic north pole 53 and a magnetic south pole 54, are arranged in sequence from top to bottom, so that a strong magnetic field is formed at the piston. When the excitation fuse is triggered by an external trigger signal, the conductive plate breaks from the pre-break, and an arc is generated at the break. The piston cutter has a strong magnetic field, and the magnetic field acts on the arc, blowing the arc apart and stretching it, and then cooling it, thereby achieving magnetic blowout. The advantage of using magnetic blowout is that under the action of the piston cutter's magnetic field, the arc can be quickly extinguished for large currents; magnetic blowout improves arc extinguishing reliability; the magnetic field acts on the arc, keeping the arc away, and there is almost no damage to the piston cutter; the arc extinguishing process is safer.

[0029] When the piston is not impacted by external force, it can be located in the lower accommodating chamber. When impacted by high-pressure gas, the piston moves downward, the limiting boss breaks and loses its limiting effect on the piston, and the piston moves downward under the guidance of the vertical groove to cut off the conductive plate. The knife-like structure of the piston is eccentrically arranged relative to the piston body to prevent the piston from being installed in reverse.

[0030] A receiving cavity is provided on the lower shell at a position corresponding to the upper shell, and the upper part of the receiving cavity is wider than the lower part of the receiving cavity, so that a limiting step is formed at the lower end of the upper part of the receiving cavity. The conductive plate 3 is recessed downward toward the receiving cavity of the lower shell, and a flat-bottomed recess is formed in the receiving cavity of the lower shell, so that the conductive plate as a whole has an inverted structure. The two ends of the bottom of the flat-bottomed recess of the conductive plate abut against the limiting step formed at the lower end of the upper part of the receiving cavity to support it. A fracture notch 31 and a bending notch 32 are spaced apart on the flat bottom part of the recess where the conductive plate is placed at the bottom of the receiving cavity. Each notch runs through the width of the conductive plate. The shape of each notch can be a V-shaped structure, a U-shaped structure, or a combination of U and V notches. The piston knife-like structure is located above the fracture notch.

[0031] At the fracture edge, see Figure 3, coated with arc-extinguishing paint or arc-extinguishing colloid 33 for assisting arc extinguishing, the material of the arc-extinguishing paint or arc-extinguishing colloid is silicone rubber or similar substances that can generate gas at high temperature. When the excitation fuse is triggered by an external trigger signal, the conductive plate breaks from the pre-break, an arc is generated at the break, and the high temperature of the arc causes the arc-extinguishing material at the break to release arc-extinguishing gas, and the arc-extinguishing material and the released arc-extinguishing gas 34 are used to assist in completing the arc extinguishing. The advantages of this solution are that with the help of the arc-extinguishing material at the pre-break of the conductive plate, the arc of large current can be extinguished quickly; the arc-extinguishing paint and colloid are not sensitive to air pressure and ambient temperature and humidity, which improves the reliability of arc extinguishing; the arc is extinguished quickly, with almost no effect on the piston knife; the arc-extinguishing paint and colloid extinguish the arc quickly, making the arc extinguishing process safer.

[0032] The lower housing housing cavity where the conductive plate is located allows the piston to move downward along the cavity. The cavity below the conductive plate allows the piston knife-shaped structure to pass through. The conductive plate is a flat plate structure. In this embodiment, the material is copper, which has a small resistance.

[0033] An auxiliary arc extinguishing device is provided at the bottom of the accommodating cavity below the conductive plate. Figure 4 The auxiliary arc extinguishing device includes an arc extinguishing medium 61 and a sealing film 62 for sealing the arc extinguishing medium. The arc extinguishing medium can be liquid or solid. The arc extinguishing liquid or arc extinguishing solid is sealed at the bottom of the accommodating cavity by a sealing film. The arc extinguishing liquid is a liquid arc extinguishing material such as fluoride liquid, and the arc extinguishing solid is a powder or granular arc extinguishing material such as quartz sand. When the excitation fuse is triggered by an external trigger signal, the conductive plate broken from the pre-break breaks through the sealing film of the arc extinguishing device and enters the arc extinguishing liquid or arc extinguishing solid, and the arc is extinguished by the arc extinguishing liquid or arc extinguishing solid to assist in cooling the arc. The advantage of this type of arc extinguishing device is that with the help of liquid or solid arc extinguishing materials, it can quickly extinguish the arc of large current. Liquid arc extinguishing materials are insensitive to air pressure and ambient temperature and humidity, which improves the reliability of arc extinguishing; powder or granular arc extinguishing materials such as quartz sand extinguish arcs with high reliability; the arc is extinguished quickly and has almost no effect on the piston knife.

[0034] The auxiliary arc extinguishing device can also be provided with an arc disturbing sheet 7 at the pre-break position of the conductive plate. The arc disturbing sheet is a plastic film or aramid paper polymer and is a flexible structure. Figure 5 , the arc disturbing piece can be set on the conductive plate, or it can be set under the conductive plate, or it can be set above and below the pre-break of the conductive plate. One end of the arc disturbing piece located on the conductive plate is fixed on the conductive plate, and the other end is a free end, which is overlapped on the conductive plate. The two ends of the arc disturbing piece located under the conductive plate are fixed on the conductive plate respectively. The installation of the arc disturbing piece is more flexible and can be adjusted according to the needs of the circuit to enhance the arc extinguishing ability. The following are five layout schemes. In actual use, the layout can be used and adjusted more flexibly to achieve the best arc extinguishing effect. At the same time, the shape of the arc disturbing piece can also be adjusted according to needs, such as an arc disturbing piece with an arc bend. See. Figure 6 In Figure a and Figure b, the arc-suspension plates are installed on the upper and lower surfaces of the conductive plate. The same end of the arc-suspension plates located on the upper and lower surfaces of the conductive plate is firmly fixed to the conductive plate, and the other end is fixed to the conductive plate with a smaller binding force. When the piston impacts the conductive plate and the conductive plate is disconnected, the end of the arc-suspension plate with a smaller binding force is separated from the conductive plate, and driven by the piston, it moves downward with the conductive plate to assist in arc extinguishing. In Figure c, two layers of arc-suspension plates are respectively arranged on the upper and lower surfaces of the conductive plate, wherein the same end of each layer of arc-suspension plates on the upper and lower surfaces is firmly fixed to one end of the conductive plate, and the other end is fixed to the other end of the conductive plate with a smaller binding force; the two ends of the other layer are fixed in the opposite direction. When the piston impacts the conductive plate and the conductive plate is disconnected, under the impact of the piston and the conductive plate, the two layers of arc-suspension plates move downward respectively to contact the bottom of the accommodating cavity, and the arc-suspension plates assist in arc extinguishing. In Figure d and Figure e, a layer of arc-suspension sheet is respectively arranged on the upper and lower sides of the conductive plate, and the firmly fixed end of the arc-suspension sheet on the conductive plate is arranged opposite to the firmly fixed end of the arc-suspension sheet located below the conductive plate, and the fixed end of the arc-suspension sheet with smaller binding force on the conductive plate is also arranged opposite to the fixed end of the arc-suspension sheet with smaller binding force located below the conductive plate. When the piston impacts the conductive plate to disconnect the conductive plate, the arc-suspension sheet moves downward and overlaps together under the drive of the piston and the conductive plate, forming an arc-suspension sheet closed structure that is approximately U-shaped or V-shaped, forming an isolation chamber, thereby enhancing the arc extinguishing ability. The advantages of setting the arc-suspension sheet are that with the help of the arc-suspension sheet, the arc of large current can be extinguished quickly; the arc-suspension sheet extinguishing can improve the arc extinguishing reliability; since the arc-suspension sheet disturbs and isolates the arc, the arc has almost no damage to the piston knife; the arc extinguishing process is safer.

[0035] On the excitation fuse, auxiliary arc extinguishing devices are arranged at different positions (piston, conductive plate, etc.). The auxiliary arc extinguishing devices at different positions can be arranged independently or in combination with several positions. Figure 7 , to achieve auxiliary arc extinguishing when the excitation fuse is disconnected.

[0036] By providing an auxiliary arc extinguishing device, the arc extinguishing capability can be improved, thereby improving the breaking capacity and working reliability of the excitation fuse.

Claims

1. An auxiliary arc extinguishing structure of an excitation fuse, comprising an upper shell and a lower shell, and a conductive plate arranged between the upper shell and the lower shell; an electronic ignition explosion device and a piston are arranged from top to bottom in the accommodating cavity of the upper shell; and an accommodating cavity for the conductive plate to fall after being disconnected is arranged on the lower shell; characterized in that An auxiliary arc extinguishing device is provided on the piston, the conductive plate or the bottom of the accommodating chamber of the lower shell alone or on at least two parts simultaneously; When the auxiliary arc extinguishing device is arranged separately on the conductive plate, the auxiliary arc extinguishing device is an arc disturbing plate or an arc extinguishing paint or colloid coated at the position where the conductive plate needs to be disconnected; one end of the arc disturbing plate is firmly connected to the conductive plate, and the other end is fixed to the conductive plate with a small bonding force, or, when the arc disturbing plate is located on the conductive plate, the other end of the arc disturbing plate is a free end overlapped on the conductive plate; when the piston disconnects the conductive plate, the other end opposite to the end of the arc disturbing plate firmly connected to the conductive plate moves toward the bottom of the accommodating cavity with the displacement of the piston.

2. The auxiliary arc extinguishing structure of the excitation fuse according to claim 1 is characterized in that The piston comprises a piston body and a knife-shaped structure located below the piston body; the auxiliary arc extinguishing device is respectively arranged on the upper side of the piston body or on the two side surfaces of the knife-shaped structure in contact with the conductive plate.

3. The auxiliary arc extinguishing structure of the excitation fuse according to claim 2 is characterized in that The auxiliary arc extinguishing device arranged on the piston body is a magnetic north pole and a magnetic south pole arranged from top to bottom on the piston body; the magnetic north pole and the magnetic south pole form a magnetic field that disturbs the arc, keeps the arc away, stretches and cools it.

4. The auxiliary arc extinguishing structure of the excitation fuse according to claim 2 is characterized in that The auxiliary arc extinguishing device on the knife-shaped structure is an arc-isolating sheet arranged on two sides of the knife-shaped structure.

5. The auxiliary arc extinguishing structure of the excitation fuse according to claim 1 is characterized in that A fracture notch is provided on the conductive plate, and the auxiliary arc extinguishing device is an arc extinguishing paint or colloid coated on the fracture notch.

6. The auxiliary arc extinguishing structure of the excitation fuse according to claim 1 is characterized in that At least one layer of the arc-suspension sheet is respectively arranged on the upper side, the lower side or the upper and lower sides of the pre-break position of the conductive plate, and the arc-suspension sheet is a flexible structure.

7. The auxiliary arc extinguishing structure of the excitation fuse according to claim 6 is characterized in that One end of the arc-suscepting plate is firmly fixed on the conductive plate, and the other end is fixed on the conductive plate with a small bonding force; A layer of arc-suspension sheet is respectively arranged on the upper and lower surfaces of the conductive plate, and the same end of the arc-suspension sheet is firmly fixed on the conductive plate. When the piston disconnects the conductive plate, the end of the arc-suspension sheet with a smaller binding force is separated from the conductive plate, and driven by the piston, it moves downward with the conductive plate to assist in arc extinguishing; or, Two layers of arc-suspension plates are respectively arranged on the upper and lower surfaces of the conductive plate, wherein the same end of one layer of arc-suspension plates on each of the upper and lower surfaces of the conductive plate is firmly fixed to one end of the conductive plate, and the fixing methods of the two ends of the arc-suspension plates of another layer on the upper and lower surfaces of the conductive plate are opposite to those of the upper and lower surfaces of the conductive plate; when the piston disconnects the conductive plate, under the impact of the piston and the conductive plate, the two layers of arc-suspension plates on the upper and lower surfaces of the conductive plate respectively move downward with the conductive plate and contact with the bottom of the accommodating cavity to assist in arc extinguishing; or, A layer of the arc-susceptor sheet is respectively arranged on the upper and lower sides of the conductive plate, and the ends of the arc-susceptor sheets on the upper and lower sides of the conductive plate that are firmly fixed are arranged opposite to each other, and the ends of the arc-susceptor sheets on the upper and lower sides of the conductive plate that are fixed with a smaller binding force are also arranged opposite to each other; when the piston impacts the conductive plate to disconnect the conductive plate, the arc-susceptor sheets move downward and overlap together under the drive of the piston and the conductive plate, forming an arc-susceptor sheet closed structure that is approximately U-shaped or V-shaped, forming an isolation chamber.

8. The auxiliary arc extinguishing structure of the excitation fuse according to claim 1 is characterized in that The auxiliary arc extinguishing device is arranged at the bottom of the accommodating cavity on the lower shell; when the conductive plate is broken, the conductive plate that is rotated and disconnected along the fixed end can contact the auxiliary arc extinguishing device.

9. The auxiliary arc extinguishing structure of the excitation fuse according to claim 8, characterized in that The auxiliary arc extinguishing device includes an arc extinguishing medium and a sealing film that seals the arc extinguishing medium. The arc extinguishing medium is an arc extinguishing liquid substance or an arc extinguishing solid substance. The arc extinguishing liquid substance or the arc extinguishing solid substance is sealed at the bottom of the accommodating cavity through the sealing film. When the piston disconnects the conductive plate, it drives the conductive plate to penetrate the sealing film and enter the arc extinguishing medium.

Images