A multi-break excitation fuse with grouped disconnection

Abstract

A grouped-disconnection multi-break excitation fuse, comprising a housing, a conductive plate, an excitation device and a breaking device. The breaking device can break the conductive plate under the drive of the excitation device; at least one cutting structure capable of cutting the conductive plate is arranged in the cavity on the other side of the conductive plate; two groups of weak disconnection points are arranged at intervals along the length direction of the conductive plate located in the housing; after the breaking device breaks the conductive plate from the first group of weak disconnection points, at least one disconnected conductive plate part that can be disengaged from the original position is formed to form a first group of break ports, and the second group of weak disconnection points are arranged on the disconnected conductive plate part; when the disconnected conductive plate part is displaced to the cutting structure, the cutting structure breaks the disconnected conductive plate part from the second group of weak disconnection points to form a second group of break ports; the first group of break ports includes at least two break ports, and the second group of break ports includes at least one break port. The excitation fuse structure of the present invention can improve the breaking capacity and arc extinguishing capacity.

Description

Technical Field

[0001] The present invention relates to the fields of power control and electric vehicles, and in particular to an excitation fuse for a current breaking method of forming multiple breaking points in groups. Background Art

[0002] The product for overcurrent protection of a circuit is a fuse that melts based on 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 case of protecting the main circuit of a new energy vehicle, if the load has a low multiple overload or short - circuit situation, selecting a fuse with a low current rating cannot meet the situation of short - time current overshoot, and if a fuse with a high current rating is selected, it cannot meet the requirement of rapid protection. In the current lithium - battery pack that provides energy for new energy vehicles, in the case of a short - circuit, the output current is about several times the rated current, and the protection time of the fuse cannot meet the requirement, resulting in the battery pack heating up, catching fire, and burning. Since both the heat generated by withstanding current and the heat generated by interrupting current melting originate from the current flowing through the fuse, such a protection device that melts by the heat of the current cannot achieve a fast enough breaking speed for a certain amplitude of fault current under the condition of having a large rated current or withstanding a strong short - time overload / impact current (such as the short - time large current when an electric vehicle starts or climbs a slope), or cannot achieve a high rated current or withstand a large overload / impact current without damage under the condition of a fast enough protection speed for a certain amplitude of fault current.

[0003] Another problem with the thermal fuse is that it cannot communicate with external devices and cannot be triggered by signals other than current, such as vehicle ECU, BMS, or other sensors. If the vehicle experiences a serious collision, is flooded, or the battery temperature is too high after being exposed to the sun, and the circuit cannot be cut off in time, it may lead to a serious event where the battery pack burns and ultimately damages the vehicle. Currently, on the market, there already exists a fast - breaking cut - off opening structure, which mainly includes a gas - generating device, a conductive terminal, and a receiving cavity after the conductive terminal drops. The gas - generating device generates high - pressure gas to drive a breaking device to break the conductive terminal, and after breaking, the conductive terminal drops downward into the receiving cavity to achieve the purpose of quickly disconnecting the circuit.

[0004] However, it still has some deficiencies and defects: The arc - extinguishing ability of a single breaking point is insufficient to break a relatively small fault current and is difficult to break a relatively large fault current. The larger the arc current, the more difficult it is to extinguish. All the arcs are concentrated on one breaking point, and the arc heats the copper busbar and air, making it easy to sustain and impossible to extinguish. During the breaking process, the arc is directly cooled by air without other structures or mechanisms to assist in arc extinguishing. Currently, a single breaking point generally can only work in an environment with a voltage of 500V or less. It is difficult to achieve breaking above 500V because the higher the voltage, the easier it is to form an arc between the breaking points, and the arc is more likely to sustain. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a multi-break excitation fuse with grouped disconnection, which can improve the breaking capacity and the arc extinguishing capacity at the same time.

[0006] To solve the above technical problem, the technical solution provided by the present invention is a multi-break excitation fuse with grouped disconnection, including a housing, a cavity is opened in the housing, a conductive plate is penetrated in the housing, dividing the cavity into two parts. An excitation device and a breaking device are sequentially arranged in the cavity on one side of the conductive plate, and the breaking device can break the conductive plate under the drive of the excitation device; it is characterized in that at least one cutting structure capable of cutting the conductive plate is arranged in the cavity on the other side of the conductive plate; two groups of weak disconnection points are arranged at intervals along the length direction of the conductive plate located in the housing; after the breaking device breaks the conductive plate from the first group of weak disconnection points, at least one disconnected conductive plate part that can be separated from the original position is formed to form the first group of break ports, and the second group of weak disconnection points are arranged on the disconnected conductive plate part; when the disconnected conductive plate part is displaced to the cutting structure, the cutting structure breaks the disconnected conductive plate part from the second group of weak disconnection points to form the second group of break ports, the first group of break ports includes at least two break ports, and the second group of break ports includes at least one break port.

[0007] Under the drive of the excitation device, the breaking device can first break the first group of weak disconnection points on the conductive plate, and then cooperate with the cutting structure in the housing to break the second group of weak disconnection points on the conductive plate, forming break ports in groups on the conductive plate.

[0008] On the end face of the breaking device on one side of the conductive plate, corresponding to the second group of weak disconnection points of the conductive plate, cavities are respectively opened, and an arc extinguishing medium or an arc extinguishing structure is arranged in the cavities.

[0009] When the arc extinguishing medium is a gas, a liquid or a solid granular substance, the arc extinguishing medium is sealed in the cavity through a sealing plate; after the cutting structure breaks the second group of weak disconnection points on the disconnected conductive plate part, the cutting structure can break the sealing plate.

[0010] The arc extinguishing structure is an arc extinguishing grid.

[0011] An arc extinguishing chamber is arranged on the inner wall of the housing through which the disconnected conductive plate part is displaced to the cutting structure, and a solidified arc extinguishing medium or an arc extinguishing grid can be arranged in the arc extinguishing chamber.

[0012] The cutting structure is a convex rib.

[0013] The weak disconnection point is one or a combination of a groove, a hole for reducing the strength of the conductive plate, and / or a reduction in the width of the conductive plate for concentrating stress, and / or a material with a lower strength than the material of the conductive plate.

[0014] At least one melt is connected to the conductive plate in the housing.

[0015] Both ends of the melt are connected in parallel to the conductive plate, and all the weak break points on the conductive plate are located between both ends of the melt.

[0016] Inside the housing, one end of the melt is connected to the outside of one or two outermost weak break points, and the other end of the melt is located outside the cutting structure; when the disconnected conductive plate part is displaced close to the cutting structure and not disconnected, the disconnected conductive plate part can be connected to one end of the melt located outside the cutting structure.

[0017] A melt is provided at the cutting structure; when the disconnected conductive plate part is displaced close to the cutting structure and not disconnected, both ends of the disconnected conductive plate part at its weak break point can be connected to both ends of the melt.

[0018] The excitation fuse of the present invention successively disconnects the conductive plate in groups on the conductive plate, successively forming multiple sets of multiple break points. Through the multiple break points formed by multiple groups of time delays, the reliability of arc extinguishing and disconnection is realized, and the breaking capacity and arc extinguishing capacity are improved. Description of the Drawings

[0019] Figure 1 , longitudinal sectional structure diagram without arc extinguishing medium.

[0020] Figure 2 , Figure 1 Structure diagram after the formation of the first set of break points of the structure.

[0021] Figure 3 , Figure 1 Structure diagram after the formation of the second set of break points of the structure.

[0022] Figure 4 , longitudinal sectional structure diagram with arc extinguishing medium.

[0023] Figure 5 , Figure 4 Structure diagram after the formation of the first set of break points of the structure.

[0024] Figure 6 , Figure 4 Structure diagram after the formation of the second set of break points of the structure.

[0025] Figure 7 , structure diagram of the conductive plate with a parallel melt, the structure between the melt and the convex rib, where F represents the melt in the figure. Among them, there are a total of five structural diagrams of the melt parallel connection schemes of ABCDE.

[0026] Figure 8, Schematic diagram of the structure after the melt is partially connected to the disconnected conductive plate, where A is Solution A and B is Solution B; F represents the melt.

[0027] Figure 9 , Circuit schematic diagrams of Solution A and Solution B, where A is Solution A and B is Solution B; F represents the melt. Specific implementation manners

[0028] For the above technical solutions, embodiments are now given and specifically described in conjunction with the drawings. The fuse of the present invention mainly includes a housing, a conductive plate, an excitation device, and a breaking device; among them.

[0029] The housing, see Figures 1 to 3 , It can be composed of an upper and lower combined housing or a left and right combined housing. In this embodiment, it is composed of an upper housing 101 and a lower housing 105. A cavity is provided in the housing. The conductive plate 104 is arranged between the upper and lower housings, dividing the cavity in the housing into two parts. An excitation device 102 and a breaking device 103 are sequentially arranged in the cavity on one side of the conductive plate. The breaking device is located between the excitation device and the conductive plate. The excitation device is fixed by a limiting step and a pressing plate (not shown) in the cavity. The excitation device can receive an external excitation signal and act to provide a driving force to the breaking device. When the excitation device is a gas generating device, the breaking device is in sealed contact with the cavity, generally realized by an interference fit between the breaking device and the cavity. The breaking device is displaced by the high-pressure gas generated by the detonation of the gas generating device. The excitation device can also be a cylinder, a hydraulic cylinder, an electromagnet drive, etc., and can all act according to the received external excitation signal.

[0030] The breaking device is fixed in the cavity through a limiting mechanism (not shown) to ensure that the breaking device is fixed at the initial position and will not be displaced in the cavity to cause misoperation. The limiting mechanism can be that small bumps are arranged at intervals on the outer periphery of the breaking device, and grooves are opened on the inner wall of the corresponding cavity, and the bumps of the breaking device are stuck into the grooves to realize position limitation. When the breaking device receives the driving force from the excitation device, this limiting mechanism can be disconnected under the impact to release the limiting effect.

[0031] The conductive plate 104, at least three disconnection weak points 107 are arranged at intervals on the conductive plate located in the housing. See Figure 1, the conductive plate inside the housing is in a trapezoidal structure. Disconnection weak points are respectively provided at the conductive plates on the inner side of the inner wall of the housing, which are called the first group of disconnection weak points. Two disconnection weak points are spaced apart on the conductive plate between the first group of disconnection weak points, which are called the second group of disconnection weak points. There are a total of four disconnection weak points in two groups. The purpose of setting the disconnection weak points is to reduce the disconnection strength of the conductive plate so that it is easier to disconnect when subjected to an impact. The disconnection weak points can be to reduce the thickness of the conductive plate or reduce the width of the conductive plate. For example, U-shaped grooves, V-shaped grooves, holes, etc. are opened on one or both sides of the conductive plate; or a structure with a reduced width of the conductive plate can be used to generate stress concentration in the transition area, such as leaving a gap; or a low-strength conductor material can be used to replace the material of the conductive plate body at the disconnection weak points, such as tin, etc.; or a prefabricated fracture formed by mechanical force pressing and / or fixing, etc.

[0032] On the end face of the breaking device on one side of the conductive plate, impact heads 108 for breaking the disconnection weak points at both ends of the conductive plate inside the housing are spaced apart. Protruding ends are respectively provided between the two impact heads 108 and at the adjacent positions corresponding to the disconnection weak points of the conductive plate. A cavity is reserved between the adjacent two protruding ends for all the disconnection weak points of the conductive plate to be disconnected. After the impact end 108 of the breaking device breaks the first group of disconnection weak points on the conductive plate to form at least two fractures in the first group, the protruding end of the breaking device abuts against the non-disconnection weak point of the disconnected conductive plate part 200, forcing the disconnected conductive plate part 200 to displace inside the housing.

[0033] At the bottom of the housing, a sharp-edged convex rib 110 is provided corresponding to the disconnection weak points on the disconnected conductive plate part 200. When the breaking device forces the disconnected conductive plate part to move to the bottom of the housing, the convex rib 110 can cooperate to disconnect the disconnection weak points on the disconnected conductive plate part 200 to form a second group of fractures, and the second group of fractures includes at least one fracture.

[0034] When there are multiple break weak points on the conductive plate, there can be multiple impact heads arranged at intervals on the breaking device, and there can also be multiple convex ridges. Taking five break weak points on the conductive plate as an example, one break weak point is provided at each end of the conductive plate inside the housing, and three break weak points are arranged at intervals between these two break weak points. The break weak points at both ends and the break weak point in the middle are the first group of break weak points, and the other two break weak points between the break weak points at both ends of the conductive plate and the middle weak point are the second group of break weak points. There are three impact heads arranged at intervals on the breaking device, corresponding to the first group of break weak points respectively, and the convex ridges on the cutting structure are set to two, corresponding to the second group of break weak points respectively. When the breaking device breaks the conductive plate, a first group of break ports and two broken conductive plate parts separated from the conductive plate are formed at the conductive plate. One unbroken break weak point is retained on each of the broken conductive plate parts; as the breaking device presses against the two broken conductive plate parts and moves to the convex ridge at the bottom of the housing, the convex ridge breaks the break weak points on the broken conductive plate parts to form the second group of break ports.

[0035] As can be seen from the above, the first group of break ports contains at least two break ports, and the second group of break ports contains at least one break port. By disconnecting the conductive plate in groups successively, multiple break ports that are disconnected at different times are formed on the conductive plate, improving the breaking ability and arc extinguishing ability.

[0036] In order to better improve the breaking ability and arc extinguishing ability, an arc extinguishing medium or an arc extinguishing structure 106 is provided in the cavity between two adjacent protruding ends of the breaking device. See Figures 4 to 6 , the arc extinguishing medium can be a gas, a liquid, or a solid granular arc extinguishing substance, and the arc extinguishing structure is an arc extinguishing grid type structure or a solid non-granular arc extinguishing substance. When the arc extinguishing medium is a gas, a liquid, or a solid arc extinguishing medium, it needs to be sealed by a sealing plate. After the sharp-edged convex ridge breaks the break weak point of the conductive plate, the convex ridge can break the sealing plate of the arc extinguishing medium, so that the arc extinguishing medium leaks from the break to cover the break weak point for arc extinguishing. An arc extinguishing structure 112 is provided on the inner wall of the housing through which the broken conductive plate part 200 between the bottom of the conductive plate housing displaces. The arc extinguishing structure here is an arc extinguishing grid type arc extinguishing structure or a solidified non-granular arc extinguishing medium. In this example, they are all arc extinguishing grid structures.

[0037] The working principle of the above structure: The excitation device receives an external excitation signal and acts to provide a driving force for the breaking device, driving the breaking device to impact and displace towards the conductive plate. The breaking device first breaks the first group of break weak points located at the inner wall of the housing to form the first group of break ports, and the first group of break ports includes at least two break ports. The conductive plate part inside the housing is disconnected. At this time, at least one unbroken break weak point, that is, the second group of break weak points, remains on the broken conductive plate part that has been separated from its original position. Figure 1The second set of weak breaking points in the middle are two unbroken weak breaking points. As the broken conductive plate part moves towards the bottom of the housing under the force of the breaking device until it reaches the dead point at the bottom of the housing, the second set of weak breaking points on the broken conductive plate part 200 are broken under the action of the convex rib at the bottom of the housing, forming a second set of fracture surfaces. The second set of fracture surfaces includes at least one fracture surface. Grouped breaking of multiple fracture surfaces on the conductive plate is achieved. When the arc extinguishing medium is gas, liquid or granular solid, the convex rib will also break the sealing plate of the arc extinguishing medium after the second set of broken fracture surfaces, so that the arc extinguishing medium pours onto the second set of fracture surfaces to participate in arc extinguishing.

[0038] The arc extinguishing principle of the above structure:

[0039] First of all, the arc resistance at the fracture surface is much greater than the resistance of the conductive plate.

[0040] Under low-magnitude fault current, after being triggered by an external excitation signal, the excitation device drives the breaking device to break the first set of fracture surfaces of the conductive plate. After the first set of fracture surfaces of the conductive plate are opened, an arc is generated. At this time, the arc is in series between the fracture surfaces of the conductive plate, and the total resistance increases compared with that before the first set of fracture surfaces are broken. The voltage at both ends of the conductive plate remains unchanged, and the fault current decreases. The breaking device continues to move downward to form a slit between it and the inner wall of the lower housing to squeeze the arc. During the movement, the arc is cooled by the arc extinguishing medium in the arc extinguishing chamber inside the lower housing, the arc resistance increases, and the fault current further decreases to a level where it is difficult to maintain the arc. The arc is completely extinguished and the fault current is cut off. The breaking device continues to move and squeezes the conductor in the middle of the first set of fracture surfaces of the conductive plate with the sharp-edged convex rib structure of the lower housing. The conductor in the middle of the first set of fracture surfaces of the conductive plate is broken at the weak point to form a second set of fracture surfaces. The second set of fracture surfaces form a clean physical fracture surface, enhancing the insulation performance after breaking.

[0041] Under high-magnitude fault current, after being triggered by an external excitation signal, the excitation device drives the breaking device to break the first set of fracture surfaces of the conductive plate. After the first set of fracture surfaces of the conductive plate are broken, an arc is generated. At this time, the arc is in series between the fracture surfaces of the conductive plate, and the total resistance increases compared with that before the first set of fracture surfaces are broken. The voltage at both ends of the conductive plate remains unchanged, and the fault current decreases. The breaking device continues to move downward to form a slit between it and the inner wall of the lower housing to squeeze the arc. During the movement, the arc is cooled by the arc extinguishing medium in the arc extinguishing chamber inside the lower housing, the arc resistance increases, and the fault current further decreases. Since it is a high-magnitude fault current, the arc can still be maintained even if the fault current further decreases. The breaking device continues to move and squeezes the conductor in the middle of the first set of fracture surfaces of the conductive plate with the sharp-edged convex rib structure of the lower housing. The conductor in the middle of the first set of fracture surfaces of the conductive plate is broken at the weak point to form a second set of fracture surfaces. A smaller arc is generated at the second set of fracture surfaces. As the breaking device cooperates with the lower housing to squeeze the arc between the second set of fracture surfaces, the arc is cooled by the arc extinguishing medium in the lower groove of the breaking device, the arc resistance continues to increase, the fault current decreases to a level where it is difficult to maintain the arc, the arc is completely extinguished, and the fault current is cut off.

[0042] To further improve the arc extinguishing effect, an auxiliary arc extinguishing melt 111 is also provided on the conductive plate.

[0043] Arc extinguishing melt setting scheme A, see Figure 7 , on both sides of the conductive plate at all the weak points of disconnection, the conductive plates are respectively connected to one end of an arc extinguishing melt 111, and the other end of the arc extinguishing melt is arranged on the bottom of the housing outside all the ridges. Before the disconnected conductive plate part 200 moves to the sharp-edged ridges at the bottom of the housing, both ends of the disconnected conductive plate part 200 are in contact connection with the arc extinguishing melt; as the breaking device continues to move, the ridges break the weak points of disconnection on the disconnected conductive plate part 200, forming a second set of break points.

[0044] Arc extinguishing melt setting scheme B, see Figure 7 , arc extinguishing melts 111 are arranged on both sides of the ridges at the bottom of the housing, and both ends of the arc extinguishing melts are slightly higher than the ridges. After the first set of break points is formed, when the disconnected conductive plate part 200 moves to the bottom of the housing, its two ends first come into contact with the two ends of the melt; as the disconnected conductive plate part 200 continues to displace and is disconnected by the ridges at the weak points of disconnection, a second set of break points is formed.

[0045] Arc extinguishing melt setting scheme C, see Figure 7 , both ends of the arc extinguishing melt are connected to the conductive plates on the two outer sides of all the weak points of disconnection of the conductive plate, forming a parallel connection with the conductive plate. After the first set of break points is formed, the current flows through the melt and melts it for arc extinguishing, and then the disconnected conductive plate part 200 forms a second set of break points again. In this scheme, the break points include two sets of break points of the conductive plate and the break points of the arc extinguishing melt.

[0046] Arc extinguishing melt setting scheme DE, see Figure 7 , one end of the arc extinguishing melt is connected to the conductive plate on one outer side of all the weak points of disconnection of the conductive plate, and the other end of the arc extinguishing melt is arranged on the bottom of the housing outside the ridges. Before the disconnected conductive plate part 200 moves to the sharp-edged ridges at the bottom of the housing, one end of the disconnected conductive plate part 200 is connected to the arc extinguishing melt; as the breaking device continues to move, cooperating with the ridges to break the weak points of disconnection on the disconnected conductive plate part 200, a second set of break points is formed.

[0047] In the above schemes, the melts in schemes ADE can be located on one side or both sides of the ridges; the melts in schemes BC can be arranged to pass through the ridges or can be arranged in the housing wall below the ridges. In short, the setting of the melts does not affect the ridges breaking the weak points of disconnection of the disconnected conductive plate part 200.

[0048] Figure 8It is a structural schematic diagram when the arc extinguishing melt is in partial contact with the disconnected conductive plate. In the figure, Figure A is the structural schematic diagram when Scheme A is in effect; Figure B is the structural schematic diagram when Scheme B is in effect. Since Schemes A, D, and E have the same principle, only Scheme A is taken as an example. For Scheme C, the melt does not contact the disconnected conductive plate part 200, so no structural schematic diagram is provided.

[0049] Figure 9 It is a circuit schematic diagram. A is the circuit schematic diagram of the arc extinguishing melt Scheme A; B is the circuit schematic diagram of the arc extinguishing melt Scheme B. Since the parallel connection methods and principles of Schemes D and E are similar to those of Scheme A, the circuit schematic diagram takes Scheme A as an example. For Scheme C, the melt is directly connected in parallel on the conductive plate, and since it is simple, no circuit schematic diagram is used for explanation.

[0050] Before the conductive plate is disconnected, the resistance of the melt (R F1 、R F2 、R F3 ) is much greater than the resistance of the conductive plate. At this time, the total resistance of the excitation fuse is approximately equal to the resistance of the conductive plate; after the conductive plate is disconnected, the arc resistance at the fracture is much greater than the resistance of the melt (R F1 、R F2 、R F3 ).

[0051] The working principle of Scheme A is as follows:

[0052] When the weak disconnection points between ac and between bd on the conductive plate are broken to form the first set of fractures, during the downward movement of the middle conductor of the conductive plate, it is connected to the melt F1 and the melt F2. The fault current will flow through the melt F1 and the melt F2. The resistance of the fractures between ac and between bd is much greater than that of the melt, so almost no arc is generated. At this time, the melt F1 and the melt F2 are connected in series in the circuit, and the total resistance increases compared with before the first set of fractures is disconnected. The voltage at both ends of the conductive plate remains unchanged, and the fault current decreases.

[0053] At this time, it is divided into three cases: Under low-magnitude fault current, the fault current flowing through fuse F1 and fuse F2 is not sufficient to melt the fuses. At this time, the weak break points between ce and de are opened to form a second set of break points. The arc generated at the second set of break points is squeezed, the arc resistance increases, the fault current decreases to a level where it is difficult to maintain the arc, the arc is completely extinguished, and the fault current is cut off; Under medium-magnitude fault current, the fault current flowing through fuse F1 and fuse F2 causes the narrow diameters of fuse F1 and fuse F2 to start melting. During the melting process, the weak break points between ce and de are opened to form a second set of break points. The arc generated at the second set of break points is squeezed, and the fuse and the second set of break points work together to extinguish the arc and break the fault current; Under high-magnitude fault current, the fault current flowing through fuse F1 and fuse F2 causes fuse F1 and fuse F2 to melt quickly, and the fault current is cut off. At this time, the opening of the second set of break points enhances the insulation performance after breaking.

[0054] The working principle of Scheme B is as follows:

[0055] When the weak break points between ac and bd on the conductive plate are broken to form a first set of break points, an arc is generated at the first set of break points. During the downward movement of the middle conductor of the conductive plate, it is connected to fuse F3. At this time, the arc of the first set of break points is in series in the circuit, and the fault current flows through the arc of the first set of break points and the conductor between cd on the conductive plate. The total resistance increases compared with before the first set of break points is disconnected. The voltage across the conductive plate remains unchanged, and the fault current decreases.

[0056] At this time, it is divided into three cases: Under low-magnitude fault current, the arc generated at the first set of break points is stretched and squeezed, the arc resistance increases, the fault current is further reduced to a level where it is difficult to maintain the arc, the arc is completely extinguished, and the fault current is cut off. The piston continues to move to open the second set of break points. In this case, the first set of break points is sufficient to break the low-magnitude fault current; Under medium-magnitude fault current, the arc generated at the first set of break points is stretched and squeezed but can still maintain the arc. After the weak break points between ce and de are opened to form a second set of break points, the fault current flows through fuse F3. Almost no arc is generated at the second set of break points. At this time, fuse F3 is in series in the circuit, and the total resistance increases compared with before the second set of break points is disconnected. The fault current is further reduced to a level where it is difficult to maintain the arc, the arc is completely extinguished, and the fault current is cut off; Under high-magnitude fault current, the arc generated at the first set of break points is stretched and squeezed but can still maintain the arc. After the weak break points between ce and de are opened to form a second set of break points, the fault current flows through fuse F3. Almost no arc is generated at the second set of break points. As fuse F3 melts, the fault current is cut off.

[0057] As can be seen from the above, adding parallel arc-extinguishing fuses can improve the breaking capacity and arc-extinguishing capacity of the fuse.

Claims

1. A grouped-disconnection multi-break excitation fuse, comprising a housing in which a cavity is provided. A conductive plate is inserted through the housing, dividing the cavity into two parts. An excitation device and a breaking device are sequentially arranged in the cavity on one side of the conductive plate. The breaking device can break the conductive plate under the drive of the excitation device; It is characterized in that at least one cutting structure capable of cutting the conductive plate is arranged in the cavity on the other side of the conductive plate; two groups of weak disconnection points are arranged at intervals along the length direction of the conductive plate located in the housing; after the breaking device breaks the conductive plate from the first group of weak disconnection points, at least one disconnected conductive plate part that can be separated from the original position is formed to form a first group of break ports, and the second group of weak disconnection points are arranged on the disconnected conductive plate part; when the disconnected conductive plate part is displaced to the cutting structure, the cutting structure breaks the disconnected conductive plate part from the second group of weak disconnection points to form a second group of break ports. The first group of break ports includes at least two break ports, and the second group of break ports includes at least one break port.

2. The grouped-disconnection multi-break excitation fuse according to claim 1, It is characterized in that on the end face of the breaking device on one side of the conductive plate, corresponding to the second group of weak disconnection points of the conductive plate, cavities are respectively provided, and an arc extinguishing medium or an arc extinguishing structure is arranged in the cavities.

3. The grouped-disconnection multi-break excitation fuse according to claim 2, It is characterized in that when the arc extinguishing medium is a gas, a liquid or a solid particulate substance, the arc extinguishing medium is sealed in the cavity by a sealing plate; after the cutting structure breaks the second group of weak disconnection points on the disconnected conductive plate part, the cutting structure can break the sealing plate.

4. The grouped-disconnection multi-break excitation fuse according to claim 2, It is characterized in that the arc extinguishing structure is an arc extinguishing grid.

5. The grouped-disconnection multi-break excitation fuse according to claim 1, It is characterized in that an arc extinguishing chamber is arranged on the inner wall of the housing through which the disconnected conductive plate part passes when displaced to the cutting structure, and a solidified arc extinguishing medium or an arc extinguishing grid can be arranged in the arc extinguishing chamber.

6. The grouped-disconnection multi-break excitation fuse according to claim 1, It is characterized in that the cutting structure is a convex rib.

7. The grouped-disconnection multi-break excitation fuse according to claim 1, It is characterized in that the weak disconnection point is one or a combination of a groove, a hole for reducing the strength of the conductive plate, and / or a reduction in the width of the conductive plate for concentrating stress, and / or a material with a lower strength than the material of the conductive plate.

8. The grouped-disconnection multi-break excitation fuse according to claim 1, It is characterized in that at least one fuse element is connected to the conductive plate in the housing.

9. The grouped-disconnection multi-break excitation fuse according to claim 8, It is characterized in that both ends of the fuse element are connected in parallel to the conductive plate, and all the weak disconnection points on the conductive plate are located between both ends of the fuse element.

10. The grouped-disconnection multi-break excitation fuse according to claim 8, It is characterized in that Inside the housing, one end of the melt is connected to the outside of one or two outermost breaking weak points, and the other end of the melt is located outside the cutting structure; when the disconnected conductive plate part is displaced close to the cutting structure and not broken, the disconnected conductive plate part can be connected to the end of the melt located outside the cutting structure.

11. The grouped-disconnection multi-break excitation fuse according to claim 1, characterized in that a melt is provided at the cutting structure; when the disconnected conductive plate part is displaced close to the cutting structure and not broken, both ends of the breaking weak point on it of the disconnected conductive plate part can be connected to both ends of the melt.

12. A power distribution unit, or an energy storage device, or a new energy vehicle, which applies an excitation fuse including at least one of the above-mentioned claims.

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