Excitation short-circuiting device

Abstract

The excitation short-circuiter comprises a shell, an excitation source, a conductive piston and cable holes, the excitation source and the conductive piston are located in the shell, the cable holes are located in the displacement path of the piston and can allow at least two cables to penetrate through, and when the cables penetrate through the cable holes, the cables are kept insulated; the excitation source can act according to a received trigger signal, high-pressure gas is released to serve as driving force to drive the piston to move, the piston can conduct cables arranged in the cable holes in a penetrating mode, and a short-circuit loop is formed between the cables. According to the excitation short-circuiting device, when a fault current occurs, positive and negative electrode cables of a circuit are short-circuited rapidly to form a short-circuit loop, an electric load behind the short-circuit loop is protected, and fusing of a fuse for circuit protection or mechanical disconnection of an excitation fuse is accelerated.

Description

Technical Field

[0001] This invention relates to the fields of power control and electric vehicles, and in particular to the energy release protection of energy storage components after the main circuit of an electrical fault is cut off. Background Technology

[0002] The main circuit of an electric vehicle battery pack contains numerous electrical loads, such as the distribution box, controller, and motor. Branch circuits from the distribution box also contain a large number of electrical loads, including heaters, compressors, and audio-visual instrument systems. When a fault occurs in the circuit, circuit protection devices are needed to protect these loads. In addition to traditional thermal fuses, main circuit protection devices also include excitation devices that use a pyrotechnic device in conjunction with a piston to quickly cut off the main circuit and employ a fusible element to extinguish the arc. Generally, one or a combination of these devices is used to achieve circuit protection for the battery pack.

[0003] However, there is still a problem that the protection device has a long operating time under small fault current. The root cause is the fusing characteristics of the fuse: the larger the current, the shorter the fusing time, and vice versa. This may cause damage to the electrical load in the circuit or cause it to overheat and catch fire after a long time. Summary of the Invention

[0004] The purpose of this invention is to provide an excitation short circuit device that, under small fault current, short-circuits the positive and negative terminals of the main circuit, allowing current to flow through the short-circuit loop and thus protecting the electrical load.

[0005] To achieve the above objectives, the present invention provides an excitation short circuit device, comprising a housing, an excitation source located within the housing, a conductive piston, and a cable hole located on the piston displacement path through which at least two cables can pass. When the cables are passed through the cable hole, the cables remain insulated from each other. The excitation source can act according to a received trigger signal, releasing high-pressure gas as a driving force to drive the piston to move. The piston can conduct electricity between the cables passing through the cable hole, thereby forming a short circuit between the cables.

[0006] Preferably, the housing comprises at least two housing portions that are detachably disposed, and the cable hole is located at the contact surface of the two housing portions that are detachably assembled.

[0007] Preferably, the housing comprises: a first housing, a second housing, and a third housing arranged in a detachable manner in sequence; the excitation source is disposed in the first housing; the piston is disposed in the second housing; and the cable hole is located at the contact surface between the second housing and the third housing. The chamber containing the excitation source, the chamber containing the piston, and the chamber containing the cable hole are interconnected, and the piston and the release end of the excitation source form a sealed cavity. When the excitation source releases a driving force to drive the piston to move, the piston makes the two cables passing through the cable hole conductive.

[0008] Preferably, a receiving groove for accommodating cables is provided at corresponding positions on the assembly end faces of the second housing and the third housing, and the receiving grooves respectively penetrate the opposite sides of the second housing and the third housing. The receiving grooves on the second housing and the third housing are joined together to form the cable hole.

[0009] Preferably, the third housing is detachably connected to the first housing or the second housing.

[0010] Preferably, the detachable connection method includes a snap-fit ​​structure, a threaded connection, or a pin connection.

[0011] Preferably, the third housing includes a third housing body and side wing plates arranged parallel to each other on both sides of the third housing. The side wing plates pass through the outer sides of the opposite sides of the second housing and are connected and fixed to the first housing by a snap-fit ​​method.

[0012] Preferably, the side wing plate is made of the same material as the third housing body and is integrally formed; or, the side wing plate is made of a different material than the third housing body and is integrally formed with the third housing body by injection molding.

[0013] Preferably, the first housing and the second housing are assembled with a sliding guide rail structure, and an assembly and fixing structure is provided inside or at the end of the sliding guide rail structure.

[0014] Preferably, when the first housing and the second housing are assembled with a sliding guide rail structure, the assembly and fixing structure is as follows: a snap-fit ​​structure is provided inside the sliding guide rail structure or on one or both sides of one end; or a hot-melt pin hole structure, tenon structure, pin connection structure or threaded connection structure is provided on one or both sides of one end of the sliding guide rail structure; or the assembly and fixing structure is formed by welding or gluing at the assembly surface of the sliding guide rail structure.

[0015] Preferably, at least one limiting structure that can be detachably assembled is provided between the contact surfaces of the second housing and the third housing.

[0016] Preferably, the piston includes a piston body and a metal insert, and the metal insert is provided with a pointed structure at the position corresponding to the cable passing through the cable hole; when the piston is displaced, the pointed structure can pierce the insulation layer of the corresponding cable, and make the cables conductive through the metal insert.

[0017] Preferably, the piston body and the end facing the cable hole are integrally formed with the metal insert.

[0018] Preferably, when two cables are threaded through, the metal insert is provided with two pointed structures facing the cable hole, and the two pointed structures are in the shape of an outward octagonal bevel.

[0019] Preferably, a groove is provided at the tail end of the piston body facing the cable hole, and the metal insert is disposed at the groove at the tail end of the piston body. A gap is maintained between the tip structure of the metal insert and the side wall of the groove of the piston body. When the tip structure of the piston is inserted into the cable, the ends of the side walls of the groove of the piston body located on both sides of the tip structure are engaged on the outside of the cable to restrict the deformation of the cable.

[0020] When a small fault current occurs in the circuit, the vehicle control system activates the circuit breaker, short-circuiting the positive and negative cables connected to the circuit breaker. The fault current flows through the short-circuit loop, protecting the electrical loads downstream of the short-circuit loop. Simultaneously, due to the short circuit, the current in the short-circuit loop increases rapidly. The system circuit detects the abnormal short-circuit current, causing the fuse to blow quickly or the activation device to trip rapidly, thus disconnecting the circuit. For large fault currents, the system can activate the circuit breaker as needed, or directly activate the protection device. After the circuit breaker activates, it can quickly transfer the fault current, protecting the electrical loads downstream of the circuit. It also shortens the activation time of the protection device, thus improving the protection of the battery pack circuit to a certain extent and avoiding safety hazards.

[0021] The modular excitation circuit breaker allows for direct assembly onto the circuit cables, simplifying installation. This device and its functionality can be added at any time without altering the existing circuit structure, resulting in low retrofit costs.

[0022] It uses a simple assembly method with snap-fit ​​fasteners, eliminating the need for wiring terminals, and is lightweight and compact.

[0023] It has no internal terminals, low internal resistance (before operation, only the resistance of the cable itself exists, and the device is not connected to the circuit), and zero power consumption in the circuit. Attached Figure Description

[0024] Figure 1This is a schematic diagram of the pre-operation excitation short circuit breaker structure.

[0025] Figure 2 Before the action Figure 1 A side view structural diagram.

[0026] Figure 3 yes Figure 1 Schematic diagram of the structure after the action.

[0027] Figure 4 yes Figure 2 Schematic diagram of the structure after the action.

[0028] Figure 5 This is a schematic diagram of the three-dimensional appearance structure of the excitation short circuit device.

[0029] Figure 6 This is a schematic diagram of the front view of the first shell structure.

[0030] Figure 7 This is a schematic diagram of the three-dimensional structure of the first shell.

[0031] Figure 8 This is a schematic diagram of the three-dimensional structure of the second shell.

[0032] Figure 9 This is a schematic diagram of the three-dimensional structure of the third shell.

[0033] Figure 10 This is a schematic diagram of an excitation short circuit breaker structure without snap-fit ​​inserts in the third housing.

[0034] Figure 11 yes Figure 10 Another perspective structural diagram.

[0035] Figure 12 It is a structural form in which the first shell and the second shell are assembled.

[0036] Figure 13 It is another structural form of assembling the first shell and the second shell.

[0037] Figure label:

[0038] Excitation source 1, first housing 2, slide groove 201, snap protrusion 202, snap protrusion 203, hot melt cylinder 204, piston 3, piston body 301, metal insert 302, limiting protrusion 303, tip structure 304, sealing ring 4, second housing 5, guide rail structure 501, limiting notch 502, receiving groove 503, limiting protrusion 504, limiting ridge 505, snap groove 506, stop block 507, cable 6, insulating layer 601, conductive layer 602, third housing 7, third housing body 701, snap insert 702, side wing plate 703, receiving groove 704, limiting protrusion 705, limiting notch 706. Detailed Implementation

[0039] The excitation short circuit device of the present invention includes a housing, an excitation source located in the housing, a conductive piston, and a cable hole located on the piston displacement path for at least two cables to pass through. When the cables are passed through the cable hole, the cables remain insulated from each other. The excitation source can act according to a received trigger signal, releasing high-pressure gas as a driving force to drive the piston to move. The piston can conduct electricity between the cables passing through the cable hole, so that a short circuit loop is formed between the cables.

[0040] The cables involved in this invention exist in user-end application scenarios. The cables are only assembled into the excitation circuit breaker of this invention when the user uses the product of this invention. Therefore, the cables are not part of the components of the excitation circuit breaker of this invention, and the cables mentioned below do not constitute a limitation of this invention.

[0041] The following describes preferred embodiments in detail with reference to the accompanying drawings. The directional terms used are for reference only and do not constitute a limitation on the technical solution of this invention.

[0042] The excitation short circuit device of the present invention, see [link / reference] Figures 1 to 5 The system includes an excitation source 1, a first housing 2, a piston 3, a second housing 5, a cable 6, and a third housing 7. The first housing 2, second housing 5, and third housing 7 are assembled sequentially, with the third housing 7 detachably fixed to the first housing 2, forming an integral housing structure. A through cavity is formed between the first housing 2 and the second housing 5. The excitation source 1 is located in the first housing 2, and the piston 3 is located in the second housing 5. A cable hole is provided between the contact surfaces of the second housing 5 and the third housing 7. After the cable 6 passes through the cable hole, it is exposed in the cavity of the second housing 5. The piston 3 is positioned corresponding to the portion of the cable 6 exposed in the cavity of the second housing 5 to facilitate the piston 3 piercing the cable 6 and establishing electrical connection between the cables.

[0043] See Figure 6 and Figure 7 The first housing 2 has cavities extending through both ends, which are used to accommodate the excitation source 1 and possible external connecting parts. Slide grooves 201 are provided on opposite sides of the end where the first housing 2 is assembled with the second housing 5, with the cavity in the first housing 2 located between the two slide grooves 201. Engraving protrusions 202 are provided on opposite outer sides of the first housing 2 along the length of the slide grooves 201.

[0044] Excitation source 1 is disposed at the top of the cavity of the first housing 2, and excitation source 1 seals the top of the cavity of the first housing 2. Excitation source 1 can be fixed by means of interference fit, adhesive bonding, or injection molding, as long as it is fixed and seals the cavity of the first housing. In this example, interference fit is used. Excitation source 1 is a gas generating device, which can generate high-pressure gas as driving force after receiving a specified trigger electrical signal. One end of the high-pressure gas release of excitation source 1 is located in the cavity of the first housing 2.

[0045] See Figure 8 The second housing 5 has a guide rail structure 501 that can pass through the groove 201 at one end corresponding to the first housing 2. When the first housing 2 and the second housing 5 are assembled, the guide rail structure 501 at the end of the second housing 5 passes through the groove 201 of the first housing 2 from one side of the first housing 2. Adhesive is applied between the assembly surfaces of the second housing 5 and the first housing 2, and the assembly of the first housing 2 and the second housing 5 is achieved through the combination of the groove guide rail structure and adhesive. A cavity extending through both ends is formed on the second housing 5, and the piston 3 is disposed in the cavity. The cross-sectional structure of the cavity matches the cross-sectional structure of the piston 3. Preferably, the cross-sectional structure of the cavity is a structure that prevents the piston 3 from rotating relative to the second housing, such as an elongated oval structure. Limiting notches 502 are respectively provided on both sides of the cavity at the end of the second housing 5 where it is assembled with the first housing 2, which can limit the initial position of the piston 3.

[0046] At one end of the second housing 5 that is in contact with the third housing 7, parallel and spaced-apart accommodating grooves 503 are provided for accommodating cables 6. The accommodating grooves 503 have a semi-circular groove structure, and the inner walls of the two accommodating grooves 503 are provided with anti-slip ribs for the cables. The accommodating grooves 503 extend through both sides of the second housing 5 and pass through the cavity of the second housing 5. That is, two accommodating grooves 503 are respectively provided on opposite sides of the cavity at the end of the second housing facing the third housing 7, allowing the cables located at the accommodating grooves 503 to be exposed in the cavity of the second housing. On both sides of the accommodating grooves 503, limiting protrusions 504 protrude from the second housing 5 and can be inserted into the third housing 7. On opposite sides of the second housing 5 along the length of the guide rail structure 501, parallel and spaced-apart limiting ridges 505 are respectively provided.

[0047] The piston 3 includes a piston body 301 and a metal insert 302. The piston body 301 has a head at the end facing the excitation source 1 and a tail at the end facing the cable hole. The metal insert 302 is integrally molded into the piston body 301 using a submerged injection molding process. The metal insert 302 has a sheet-like structure with a rectangular cross-section formed by punching out two trapezoidal tips, resulting in a pointed structure 304 at the end of the metal insert 302 facing the cable 6. The piston body 301 has two protruding ridges on both sides and a recessed structure in the middle at the piston tail. The metal insert 302 is submerged in the middle recess, with the pointed structure 304 of the metal insert 302 extending beyond the tail of the piston body 301. The advantage of this structure is that after the piston 3 is driven to move, the cable 6 will deform due to the impact force of the piston 3. The protruding ridges on both sides of the piston body 301 can contain the outer side of the cable 6, limiting the deformation range of the cable 6, causing the cable 6 to deform towards the tip structure of the inner metal insert 302. The tip structure of the metal insert 302 pierces the insulation layer of the two cables 6 and makes contact with the internal conductive layer of the two cables 6 respectively, so that the two cables 6 are short-circuited and connected through the metal insert 302. The inner sides of the two tip structures 304 of the metal insert 302 form an outward octagonal bevel structure. When the piston moves to the position, the outward octagonal bevel structure can increase the contact area with the conductive layer of the cable 6.

[0048] A limiting protrusion 303 is provided at the head of the piston body 301 corresponding to the limiting notch 502 of the second housing 5. A sealing groove is provided on the outer periphery of the piston body 301, and a sealing ring 4 is provided in the sealing groove. When the piston 3 is installed in the cavity of the second housing 5, the limiting protrusion 303 of the piston 3 is engaged at the limiting notch 502 of the second housing to position the piston 3 at its initial position. The piston body 301 of piston 3 has an elongated oval head section, and the cavity of the second housing 5 on which piston 3 is mounted also has an elongated oval structure, matching the head shape of piston body 301. The elongated oval head of piston body 301 is used to directly bear pressure and play a certain sealing role. The head of piston body 301 is in sealed contact with the inner wall of the cavity of the second housing 5, and relative sealing can be achieved through reasonable dimensional matching; or the sealing ring 4 between the contact surface of piston body 301 head and cavity of the second housing 5 can be used to achieve sealed contact between piston body 301 head and cavity of the second housing 5, forming a sealed chamber between piston 3 and excitation source 1.

[0049] A limiting step is provided in the cavity of the second housing to limit the displacement distance of the piston 3.

[0050] Third shell 7, see Figure 9The system includes a third housing body 701 and a snap-fit ​​insert 702. The snap-fit ​​insert 702 is integrally formed with the third housing body 701 by injection molding. The snap-fit ​​insert is made of metal. The snap-fit ​​insert 702 includes side wing plates 703 located on opposite sides of the third housing and arranged in parallel. A snap-fit ​​hole is provided on the side wing plate 703 at a position corresponding to the snap-fit ​​protrusion 202 of the first housing 2.

[0051] A receiving groove 704 is provided at one end of the second housing 7 where it is assembled with the second housing 5, corresponding to the receiving groove 503 of the second housing 5 for accommodating the cable 6. The receiving groove 704 extends through the opposite sides of the third housing 7. Cable anti-slip ribs are provided on the inner walls of the two receiving grooves 704. The receiving grooves 704 are located between the side wing plates 703 of the snap-fit ​​insert 702. The shape of the receiving groove 704 is a semi-circular groove structure. When the second housing 5 and the third housing 7 are assembled, the receiving grooves 503 and 704 align at the contact surface of the second housing 5 and the third housing 7 to form a cable hole for the cable 6 to pass through. Only the receiving groove 704 exists in the cavity of the second housing 5. When the cable 6 passes through the cable hole, the portion of the cable 6 located in the cavity of the second housing 5 is exposed in the cavity of the second housing 5, and is provided corresponding to the tip structure 304 of the piston 3.

[0052] Cable anti-slip ribs are respectively provided on the inner walls of the receiving grooves 503 and 704 of the second housing 5 and the third housing 7. The cable anti-slip ribs are shaped like gears and can clamp the cable 6 to prevent the cable 6 from sliding.

[0053] Limiting protrusions 705 are provided at a certain distance on the outer side of the two receiving grooves 704, and the limiting protrusions 705 are provided with limiting notches at the cavities of the second housing. Along the length direction of the receiving grooves 704, a limiting notch 706 is provided at the position corresponding to the limiting protrusion 504 of the second housing 5.

[0054] During assembly, the concave-convex structure formed by the nested engagement of the limiting protrusion 705 on the inner side of the third housing 7 and the limiting notch in the cavity of the second housing 5 becomes a first-level limiting structure between the assembly surfaces of the third housing and the second housing. The concave-convex structure formed by the nested engagement of the limiting notch 706 on the two outer sides of the third housing 7 and the limiting protrusion 504 on the second housing 5 becomes a second-level limiting structure between the assembly surfaces of the third housing and the second housing, preventing relative displacement between the second housing and the third housing.

[0055] The cross-sectional shape of the positioning protrusion and the corresponding positioning notch in the second and third housings can be one or a combination of circles, triangles, rectangles or polygons.

[0056] When the first housing 2, the second housing 5, and the third housing 7 are assembled, the guide rail structure of the second housing 5 passes through the sliding groove structure 201 of the first housing 2, the limiting protrusion 504 of the second housing 5 is engaged at the limiting notch 706 of the third housing 7, and the limiting protrusion 705 of the third housing is engaged at the limiting notch in the cavity of the second housing 5; the cable 6 is accommodated and fixed in the cable hole formed after the accommodating grooves (503, 704) are joined, and the side wing plate 703 of the buckle insert 704 of the third housing passes through the side between the two limiting protrusions 505 of the second housing 5, so that the buckle on the side wing plate 703 is engaged on the buckle protrusion 202 on the outside of the first housing 2. The side wing plate 703 is located on the outside of the end of the sliding groove guide rail structure of the first and second housings, thus limiting the position of the sliding groove guide rail structure; thereby assembling and fixing the first housing 2, the second housing 5, and the third housing 7.

[0057] Cable 6 is the two cables connecting the positive and negative terminals in the user-end system circuit. The cross-section is generally circular and consists of an outer insulating layer 601 and an inner conductive layer 602. The outer insulating layer is made of plastic, commonly polyvinyl chloride (PVC), polyethylene (PE), and cross-linked polyethylene (XLPE). The inner conductive layer is generally made of copper.

[0058] Working principle:

[0059] Under normal operating conditions, the two cables 6 remain insulated from each other.

[0060] When the excitation source 1 receives the trigger electrical signal, it releases high-pressure gas as a driving force to drive the piston 3 to overcome the displacement of the limiting structure. The two conductive tips of the metal insert 302 of the piston 3 are respectively inserted into the insulation layer of the corresponding cable 6 and make conductive contact with the conductive layer in the cable 6. Since the metal insert 302 is made of conductive material, the two cables 6 are connected through the metal insert 302 to form a short circuit loop. The current flows through the short circuit loop, forming protection for the electrical load after the short circuit loop.

[0061] In some embodiments, the third housing 7 may not have the snap-fit ​​insert 702, and the side wing plate may be integrally formed on the third housing body. See Figure 10 The side wing plates are fixed to the first shell through structures such as hook structures and snap-fit ​​structures that facilitate fixed connection.

[0062] In some embodiments, an assembly and fixing structure for the first and second housings can be added to prevent relative movement between them. For example, the first and second housings can be fixedly connected by welding, such as ultrasonic welding or laser welding, at their assembly surfaces. Alternatively, adhesive can be applied to the assembly surfaces of the slide rail structure for fixation. A snap-fit ​​structure or a hot-melt pinhole structure can also be provided inside or on the end face of the slide rail structure of the first and second housings to fix the assembly surfaces. The welding connection between the first and second housings does not affect the separate assembly on the cable 6.

[0063] For example, a snap-fit ​​structure can be installed inside or on the end face of the sliding guide rail structure of the second housing 5 and the first housing 2 to achieve assembly and fixation. See [link / reference] Figure 12 A latching groove 506 is provided on one side of the second housing 5 where it connects to the first housing 2. A latching protrusion 203 is provided on one side of the first housing 2 at the position corresponding to the latching groove 506. During assembly, the first housing 2 slides onto the side of the second housing 5 without the latching groove 506, allowing the latching protrusion 203 of the first housing to pass through the latching groove 506 of the second housing and lock in place, preventing the first housing 2 from detaching from the second housing 5. The first and second housings are further secured by the side wing plate of the third housing 7, which passes through the outer side of the second housing, to prevent them from coming off.

[0064] An assembly and fixing structure different from the first housing 2 and the second housing 5 in the above embodiments can also be added, see [link / reference] Figure 13 A groove is provided on the end face of the second housing 5 where it connects to the first housing 2. A stop block 507 is provided on one or both sides of the groove, and a round hole is provided on the stop block. The end face of the first housing 2 is provided with a guide rail structure corresponding to the groove of the second housing 5. A hot-melt cylinder 204 is provided at the end of the guide rail structure of the first housing 2. During assembly, the guide rail structure of the first housing 2 slides into the groove of the second housing 5 from the side of the groove of the second housing without the stop block 507 structure. When it slides into place, the cylinder 204 of the first housing 2 enters the round hole of the stop block 507 of the second housing 5. The hot-melt cylinder 204 passes through one end of the round hole of the stop block 507, thereby fixing the hot-melt cylinder 204 and the stop block 507. The first housing and the second housing are then bound and fixed by the side wing plate of the third housing 7. In addition, corresponding mutually aligned stop blocks with round holes can be provided at one or both ends of the assembly point of the first housing and the second housing. After the first housing and the second housing are assembled in place by the slide rail structure, pins or screws are provided in the round holes of the two stop blocks to achieve the positioning of the first housing and the second housing.

[0065] The assembly surfaces of the first and second shells can also be assembled and fixed using mortise and tenon joints.

[0066] In the above embodiments, the third housing 7 spans the second housing 5 and is assembled and fixed to the first housing 2 by a detachable snap-fit ​​structure. In other embodiments, the third housing 7 and the second housing 5 can also be assembled and fixed by a snap-fit ​​structure, or the third housing 7 can be fixed to the first housing or the second housing by a threaded connection or a pin connection. For example, screws pass through the first housing, the second housing and the third housing for threaded connection, and the third housing and the second housing are provided with aligned pin holes at their assembly surfaces for connection and fixation by pins.

[0067] In practical applications, the third housing of the circuit breaker is first disassembled, and then the first and second housing assemblies with excitation source and piston are assembled and placed on the cable 6, and the third housing is placed below the cable 6. Then the third housing is connected and fixed to the first or second housing, and the cable is clamped.

Claims

1. An excitation short-circuit device, characterized in that, The device includes a housing, an excitation source located within the housing, a conductive piston, and a cable hole located on the piston's displacement path through which at least two cables can pass. When the cables are passed through the cable hole, the cables remain insulated from each other. The excitation source can activate according to a received trigger signal, releasing high-pressure gas as a driving force to drive the piston to move. The piston can conduct electricity between the cables passing through the cable hole, forming a short-circuit loop between the cables.

2. The excitation short-circuit device according to claim 1, characterized in that, The housing includes at least two housing portions that are detachably disposed, and the cable hole is located at the contact surface of the two housing portions that are detachably assembled.

3. The excitation short-circuit device according to claim 2, characterized in that, The housing includes a first housing, a second housing, and a third housing arranged in a detachable manner. The excitation source is disposed in the first housing, the piston is disposed in the second housing, and the cable hole is located at the contact surface between the second housing and the third housing. The chamber containing the excitation source, the chamber containing the piston, and the chamber containing the cable hole are interconnected. The piston and the release end of the excitation source form a sealed cavity. When the excitation source releases a driving force to drive the piston to move, the piston makes the two cables passing through the cable hole conductive.

4. The excitation short-circuit device according to claim 3, characterized in that, Cable receiving grooves are respectively provided at corresponding positions on the assembly end faces of the second housing and the third housing. The cable receiving grooves pass through the opposite sides of the second housing and the third housing, and the cable holes are formed when the cable receiving grooves on the second housing and the third housing are joined together.

5. The excitation short-circuit device according to claim 3, characterized in that, The third housing is detachably connected to the first housing or the second housing.

6. The excitation short-circuit device according to claim 5, characterized in that, Detachable connection methods include snap-fit ​​structures, threaded connections, or pin connections.

7. The excitation short-circuit device according to claim 6, characterized in that, The third housing includes a third housing body and side wing plates arranged parallel to each other on both sides of the third housing. The side wing plates pass through the outer sides of the opposite sides of the second housing and are connected and fixed to the first housing by a snap-fit ​​method.

8. The excitation short-circuit device according to claim 7, characterized in that, The side wing plate is made of the same material as the third housing body and is integrally formed, or the side wing plate is made of a different material than the third housing body and is integrally formed with the third housing body by injection molding.

9. The excitation short-circuit device according to claim 3, characterized in that, The first housing and the second housing are assembled with a sliding guide rail structure, and an assembly and fixing structure is provided inside or at the end of the sliding guide rail structure.

10. The excitation short-circuit device according to claim 9, characterized in that, When the first housing and the second housing are assembled with a sliding guide rail structure, the assembly and fixing structure is as follows: a snap-fit ​​structure is provided inside the sliding guide rail structure or on one or both sides of one end; or a hot-melt column hole structure, tenon structure, pin connection structure or threaded connection structure is provided on one or both sides of one end of the sliding guide rail structure; or the assembly and fixing structure is formed by welding or gluing at the assembly surface of the sliding guide rail structure.

11. The excitation short-circuit device according to claim 3, characterized in that, At least one limiting structure that can be detachably assembled is provided between the contact surfaces of the second housing and the third housing.

12. The excitation short-circuit device according to any one of claims 1 to 11, characterized in that, The piston includes a piston body and a metal insert. The metal insert has a pointed structure at the position corresponding to the cable passing through the cable hole. When the piston is displaced, the pointed structure can pierce the insulation layer of the corresponding cable and make the cables conductive through the metal insert.

13. The excitation short-circuit device according to claim 12, characterized in that, The piston body and the end facing the cable hole are integrally formed with the metal insert.

14. The excitation short-circuit device according to claim 13, characterized in that, When two cables are threaded through, the metal insert is provided with two pointed structures facing the cable hole, and the two pointed structures are in the shape of an outward octagonal bevel.

15. The excitation short-circuit device according to claim 12, characterized in that, A groove is provided at the tail end of the piston body facing the cable hole. The metal insert is disposed at the groove at the tail end of the piston body. A gap is maintained between the tip structure of the metal insert and the side wall of the groove of the piston body. When the tip structure of the piston is inserted into the cable, the ends of the side walls of the groove of the piston body located on both sides of the tip structure are engaged on the outside of the cable to restrict the deformation of the cable.

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