A step-by-step disconnection double-break excitation fuse

Abstract

A step-by-step disconnection double-break excitation fuse, comprising a housing, an excitation device, a power device and a conductive plate. An adjacent first cavity and a second cavity are formed in the housing, and the first cavity and the second cavity are partially communicated; the conductive plate passes through the housing, the first cavity and the second cavity; the excitation device and the power device are sequentially arranged in the first cavity; a slider is arranged in the second cavity, and one end of the slider extends into the first cavity through the connection part communicated with the first cavity; when the power device disconnects the conductive plate in the first cavity under the drive of the excitation device, the end of the slider extending into the first cavity can be extruded to drive the slider to disconnect the conductive plate in the second cavity. The excitation fuse of the present invention has a wide breaking current range, high arc extinguishing ability and excellent insulation performance after breaking.

Description

Technical Field

[0001] The present invention relates to the fields of power control and electric vehicles, and in particular to an excitation fuse that cuts off the current transmission circuit through an external signal control. 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 fast 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 current - heat tolerance and the current - heat for breaking cause melting due to the current flowing through the fuse, such a protection device that melts by current heating cannot achieve a fast enough breaking speed for a certain amplitude of fault current under the condition of having a large rated current or tolerating 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 tolerate 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 has 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 finally damages the vehicle.

[0004] Currently, there is already a fast - breaking cut - off opening structure on the market, which mainly includes an electronic ignition device, a conductive plate, and a receiving cavity after the conductive plate drops. The electronic ignition device generates high - pressure gas to drive a power device to break the conductive plate, and after breaking, the conductive plate drops downward into the receiving cavity to achieve the purpose of quickly disconnecting the circuit. However, it still has some deficiencies and defects, resulting in limited arc - extinguishing ability: due to being a single - break port, the arc - extinguishing ability is low, and it is difficult to break large fault currents. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a double - break excitation fuse, which improves the arc - extinguishing ability and breaking ability by increasing the break ports, and improves the insulation resistance after breaking through the step - by - step action of the break ports.

[0006] To solve the above technical problems, the technical solution provided by the present invention is a step-by-step disconnecting double-break excitation fuse, which includes a housing, an excitation device, a power device, and a conductive plate. It is characterized in that adjacent first and second cavities are provided on the housing, and the first and second cavities are partially connected; the conductive plate passes through the housing, the first cavity, and the second cavity; the excitation device and the power device are sequentially arranged in the first cavity; a slider is arranged in the second cavity, and one end of the slider extends into the first cavity through the connection with the first cavity; when the power device disconnects the conductive plate in the first cavity under the drive of the excitation device, it can squeeze one end of the slider extending into the first cavity to drive the slider to disconnect the conductive plate in the second cavity. The conductive plate is in sealed contact with the housing, and the power device is in sealed contact with the first cavity.

[0007] The place where the conductive plate is impacted by the power device and the slider is the weak point for disconnection.

[0008] Pointed structures are arranged at the corresponding positions of the power device and the slider where they impact the weak point for disconnection of the conductive plate.

[0009] The slider is an arc-shaped slider, and the second cavity has an arc-shaped surface for the arc-shaped slider to fit and slide.

[0010] In the first cavity and the second cavity, bending weak points corresponding to the weak point for disconnection are respectively provided.

[0011] On the basis of the above structure, in order to improve the arc extinguishing ability, at least one fuse element can be connected in parallel on the conductive plate. The two ends of the fuse element are respectively located on both sides of the weak point for disconnection of the conductive plate in the first cavity. Or the two ends of the fuse element are respectively located on both sides of the weak points for disconnection of the conductive plate in the first cavity and the second cavity.

[0012] An arc extinguishing chamber filled with an arc extinguishing medium is provided on the housing; the narrow diameter part of the fuse element is arranged in the arc extinguishing medium.

[0013] The conductive plate is in sealed contact with the housing, and the power device is in sealed contact with the first cavity.

[0014] The fuse of the present invention can be applied in a power distribution unit, or an energy storage device, or a new energy vehicle for circuit protection.

[0015] Compared with traditional excitation fuses, the advantages of the excitation fuse of the present invention are as follows:

[0016] 1. The double-break design reduces the voltage applied to each break to only 1 / 2 of that of a single break, lowering the recovery voltage across the arc gap, enabling the interruption of arcs at higher voltage levels, and enhancing the breaking voltage.

[0017] 2. The two breaks are delayed in opening and the fuse melts, allowing the later-opened break to have a lower fault current and temperature, making it easier to cut off the arc and resulting in excellent post-interruption insulation performance. At the same time, it broadens the current interruption range, improves the arc-extinguishing and breaking capabilities, and ensures reliable insulation performance after interruption.

[0018] 3. The time for the second break to open can be delayed by adjusting the angle and size of the arc-shaped slider, creating more favorable conditions for arc extinction at the second break, thus enhancing the breaking ability.

[0019] 4. The power device and the housing are relatively sealed to prevent gas from entering the arc-extinguishing chamber and affecting interruption, while also preventing the arc from entering the chamber where the excitation device is located and damaging the drive circuit.

[0020] 5. The housing has a sealed design without ventilation holes, which can prevent foreign objects from contaminating the breaks and also prevent high-temperature arcs from spraying out of the housing and damaging surrounding components, improving the protection level.

[0021] 6. The double-break excitation fuse product with step-by-step rotational disconnection has the same weight, the same volume, and no significant increase in cost compared to the single-break excitation fuse. Description of the Drawings

[0022] Figure 1 Schematic cross-sectional view of the excitation fuse before the parallel fuse is added and before disconnection.

[0023] Figure 2 Schematic cross-sectional view of the excitation fuse before the parallel fuse is added and after disconnection.

[0024] Figure 3 Schematic cross-sectional view of the excitation fuse with the parallel fuse added and before disconnection.

[0025] Figure 4 Schematic cross-sectional view of the excitation fuse with the parallel fuse added and before disconnection. Detailed Implementation Manner

[0026] For the above technical solutions, embodiments are now given and specifically described in conjunction with the drawings. The excitation fuse of the present invention mainly includes a housing, a conductive plate, an excitation device, and a power device; see Figures 1 to 4 wherein.

[0027] The housing can be composed of an upper housing and a lower housing or a left housing and a right housing, and a sealing device is provided at the combined contact surface. In this embodiment, it is composed of an upper housing 102 and a lower housing 106. A first cavity 107 penetrating the upper end of the housing is provided in the housing, and a second cavity 108 is provided on one side of the lower part of the first cavity. The lower ends of the first cavity 107 and the second cavity 108 are communicated. A conductive plate 104 is penetrated in the housing, and the conductive plate 104 passes through the cavities 107 and 108 and the partition 109 between the two cavities, and the conductive plate separates the two cavities into two parts respectively. The two side walls of the partition 9 are plane structures, and the free end face is an arc surface structure. An excitation device 101 and a power device 103 are sequentially arranged from top to bottom in the first cavity above the conductive plate. The excitation device 101 is fixedly arranged at the top of the first cavity and is limited by a limiting step arranged in the vertical cavity, and its upper part can be fixed by a pressing plate or a pressing sleeve (not shown). The excitation device is an electronic ignition device in this embodiment, which can receive an excitation signal when a fault occurs sent from the outside, ignite and detonate to generate high-pressure gas, form a driving force, and drive the power device to act.

[0028] The power device 103 is located in the first cavity between the excitation device and the conductive plate, above the part of the conductive plate located in the cavity, and there is a certain distance between its impact end and the conductive plate to ensure the impact force of the power device. A sealing device is provided at the contact surface between the power device and the first cavity to ensure that all the driving force generated by the excitation device acts on the power device without side leakage, so as to avoid insufficient driving force, prevent gas from entering the fracture of the conductive plate and affecting arc extinction; at the same time, prevent the arc from entering the chamber part where the power excitation device is located when disconnected, which may affect the driving circuit. The sealing device is an O-ring in this embodiment. When the power device is not driven by the driving force and is in its initial position, a limiting mechanism (not shown) is provided at the contact surface between the power device and the cavity to ensure that the power device is fixed in the initial position and will not displace in the cavity to cause misoperation. The limiting mechanism can be that small bumps are arranged at intervals on the outer periphery of the power device, and grooves are opened on the inner wall of the corresponding cavity, and the bumps of the power device are clamped into the grooves to achieve position limitation. The limiting mechanism can be disconnected under impact when the power device receives the driving force from the excitation device to release the limiting effect. An impact cutter head is provided below the power device, and the impact cutter head is a pointed structure. The pointed structure can be an acute angle structure where one side is a straight surface and the other side is an inclined surface, a conical pointed angle structure where both sides are inclined surfaces intersecting, or other structures that are beneficial to cutting the conductive plate. In this embodiment, the power device is a piston, its impact cutter head is an inclined surface pointed angle structure, and the inclined surface pointed angle structure of the impact cutter head is arranged on the side close to the housing wall.

[0029] A break weak point 110 is formed on the conductive plate corresponding to the impact cutter head of the power device. The break weak point is a V-shaped groove, a U-shaped groove or other structures that can reduce the strength of the break point of the conductive plate and penetrate the width of the conductive plate on one or both sides of the conductive plate. In this embodiment, the break weak point is arranged on the conductive plate on the side close to the first cavity corresponding to the beveled corner structure of the impact cutter head; a bending weak point 111 is formed on the conductive plate on the other side of the first cavity close to the partition plate.

[0030] The second cavity 108 has an arc-shaped surface on the side opposite to the partition plate, and the lower end surface of the partition plate 109 at the second cavity is arranged as an arc-shaped surface. The arc-shaped slider 105 is arranged in the second cavity, and both of its two sides are arc-shaped surfaces, and both ends are plane structures. A limiting mechanism (not shown) is arranged on the arc-shaped slider to ensure that the arc-shaped slider is located at the initial position when no external force is applied. In the initial position, the arc-shaped slider 105 is located at the second cavity where the lower end surface of the partition plate 109 is located. One arc-shaped surface of the arc-shaped slider fits and abuts against the arc-shaped surface of the second cavity opposite to the partition plate, and the arc-shaped end surface of the free end of the partition plate fits and abuts against the other arc-shaped surface of the arc-shaped slider. When the arc-shaped slider is located at the initial position, one end of it protrudes into the first cavity, and the end surface of the part located in the first cavity is a bevel structure at the initial position; the other end of it is located in the second cavity, and the end surface is also a bevel structure at the initial position. On the conductive plate located in the second cavity, a break weak point 112 is arranged at the position of the end surface of the arc-shaped slider closest to the conductive plate, and a bending weak point 113 is arranged on the conductive plate on the other side of the second cavity opposite to the break weak point. The bevel structure requirements at both ends of the arc-shaped slider are as follows: when the power device breaks the conductive plate in the first cavity, the power device will press the end surface of the arc-shaped slider located in the first cavity, driving the arc-shaped slider to overcome its limiting mechanism and move along the second cavity to impact the conductive plate located in the second cavity. Since the end surface of the arc-shaped slider corresponding to the break weak point of the conductive plate in the second cavity is a beveled corner structure, under the action of a huge pressing force, the arc-shaped slider breaks the conductive plate located in the second cavity. Since when the power device moves to the dead center position, its side tightly abuts against the end surface of the arc-shaped slider to position the arc-shaped slider, and the broken conductive plates are isolated by the arc-shaped slider. Adjusting the angle and size of the arc-shaped slider can delay the time when the break of the conductive plate in the second cavity breaks.

[0031] The above-mentioned power device and arc-shaped slider are both made of insulating materials. The slider arranged in the second cavity can be an arc-shaped slider or a slider with other structures, and only needs to meet the requirement that the inclined surface of the slider extending into the first cavity can be squeezed by the power device and move in the second cavity to cut off the conductive plate located in the second cavity. The structure of the second cavity only needs to meet the requirement that the slider can break the conductive plate located in the second cavity when an external force is applied. The combination of the arc-shaped slider and the cavity with an arc-shaped surface can make the fuse smaller in volume and the slider run more smoothly.

[0032] Working principle of the excitation fuse with the above structure:

[0033] When the excitation device receives an external excitation signal, ignition and detonation generate a large amount of high-pressure gas, driving the power device to move rapidly towards the conductive plate; the power device impacts the cutter head to impact the conductive plate and break the weak part, and the first break of the conductive plate forms the first fracture on the conductive plate;

[0034] When the fault current is large, a large arc will be generated after the first fracture is broken. Since only air medium is used for arc extinguishing, at this time, the first fracture is in an arc-holding state. At this time, the power device has an interference fit with the inner wall of the housing and the bent part of the conductive plate to form an interference line, squeezing the arc generated at the first fracture. Then the arc is stretched, the arc diameter is compressed, the arc resistance increases, and the fault current decreases; the power device continues to move and presses against the arc-shaped slider, pressing the arc-shaped slider to move and impact the weak part of the conductive plate in the second cavity to break the conductive plate for the second time, forming the second fracture in the second cavity; at this time, the arc-shaped slider and the arc-shaped surface in the second cavity are closely fitted, squeezing the arc generated at the second fracture, prompting the arc to be quickly extinguished. Since the fault current interrupted by the second fracture is lower and the temperature is lower, the post-breakdown insulation performance of the second fracture is excellent, ensuring the reliability of the conductive plate disconnection.

[0035] When the fault current is small, the two fractures can better perform disconnection and arc extinguishing.

[0036] Therefore, when no other arc extinguishing measures are adopted and only air arc extinguishing is used, by disconnecting in two steps and quickly extinguishing the arc through the two fractures, the arc extinguishing ability and disconnection reliability are improved.

[0037] In order to better improve the arc extinguishing ability and disconnection ability, auxiliary arc extinguishing can also be added on this basis to achieve rapid arc extinguishing. See Figure 3 and Figure 4 , a fuse 114 for arc extinguishing is connected in parallel on the conductive plate located at the first cavity and the second cavity. An arc extinguishing cavity 115 is provided on the housing, and an arc extinguishing medium is filled in the arc extinguishing cavity. The fuse 114 is arranged in the arc extinguishing medium, and both ends thereof pass through the obstacles on the housing and are connected in parallel with the conductive plate. A narrow diameter is provided on the fuse, and the narrow diameter of the fuse is located in the arc extinguishing medium. The positions where both ends of the fuse are connected in parallel with the conductive plate need to meet the requirement that the fuse is still in a conducting state when the conductive plate is first disconnected, and the fuse can be melted before the second disconnection. See Figure 3 and Figure 4 , one end of the fuse is connected to the conductive plate located outside the weak disconnection part 110, and the other end is connected to the conductive plate at the partition (between the weak bending part 111 and the weak bending part 113) or connected to the conductive plate located outside the weak disconnection part 112. The part of the housing where the arc extinguishing chamber is located can be manufactured separately.

[0038] Figure 3 Working principle of the parallel melt in the middle:

[0039] The resistance of the melt connected in parallel on the conductive plate is greater than that of the conductive plate, and the arc resistance generated at the fracture is much greater than the melt resistance.

[0040] Under low-magnitude fault current, the excitation device receives an excitation signal to trigger the generation of high-pressure gas, which then pushes the power device to first break the first weak break point of the conductive plate to form the first fracture. The low-magnitude fault current is transferred to the melt connected in parallel at both ends of the first fracture of the conductive plate. The heat generated when it flows through the narrow path of the melt is not enough to melt the narrow path, only playing a current-limiting role. At this time, the melt is in series with the second weak break point on the conductive plate. Compared with the total resistance before the first fracture is broken, the total resistance increases, and the voltage at both ends of the conductive plate remains unchanged, so the fault current decreases. The power device continues to move and then compresses the arc-shaped slider to open the second fracture, where the reduced fault current is interrupted, and the arc extinguishes within a very short time. Through the two fractures and the melt, rapid arc extinguishing and breaking ability are achieved.

[0041] Under medium-magnitude fault current, the excitation device receives an excitation signal to trigger the generation of high-pressure gas, which then pushes the power device to first break the first weak break point of the conductive plate to form the first fracture. The medium-magnitude fault current is transferred to the melt connected in parallel at both ends of the first fracture of the conductive plate. Heat is generated when it flows through the narrow path of the melt, and melting begins at the narrow path of the melt. At this time, the melt is in series with the second weak break point on the conductive plate. Compared with the total resistance before the first fracture is broken, the total resistance increases, and the voltage at both ends of the conductive plate remains unchanged, so the fault current decreases. During the melting process of the melt, the power device continues to move and then compresses the arc-shaped slider to open the second fracture. At this time, the melt and the second fracture jointly interrupt the reduced fault current. At this time, the arc extinguishing medium also participates in arc extinguishing to extinguish the arc, and rapid arc extinguishing can be achieved. In this case, the first fracture is hardly burned by the arc, and the insulation performance after breaking is excellent.

[0042] Under high-magnitude fault current, the excitation device receives an excitation signal to trigger the generation of high-pressure gas, which then pushes the power device to first break the first weak break point of the conductive plate to form the first fracture. The high-magnitude fault current quickly transfers to the melt connected in parallel at both ends of the first fracture of the conductive plate. Due to the large fault current, a large amount of heat is generated at the narrow path of the melt and it quickly melts. An arc is generated at the melted narrow path of the melt, and the arc extinguishing medium participates in arc extinguishing, causing the arc to quickly extinguish. At this time, the power device continues to move and then compresses the arc-shaped slider to open the second fracture, forming a physical fracture and increasing the insulation ability after breaking, further ensuring the reliability of disconnection.

[0043] Figure 4In the melt parallel connection mode, the two breaking ports are located between the two ends of the parallel melt and the connection with the conductive plate. When starting to break, after the excitation device receives an excitation signal and triggers to generate high-pressure gas, it pushes the power device to first break the first weak breaking point of the conductive plate to form the first breaking port. The fault current quickly transfers to the melt connected in parallel with both ends of the conductive plate. At this time, the arc is mainly extinguished by the melting of the narrow path of the melt in the arc extinguishing medium. The power device continues to move and then compresses the arc-shaped slider to open the second breaking port only to increase the insulation ability after breaking.

Claims

1. A step-by-step disconnecting double-break excitation fuse, comprising a housing, an excitation device, a power device and a conductive plate, characterized in that adjacent first and second cavities are formed on the housing, and the first and second cavities are partially communicated; the conductive plate passes through the housing, the first cavity and the second cavity; the excitation device and the power device are sequentially arranged in the first cavity; a slider is arranged in the second cavity, and one end of the slider extends into the first cavity through the connection part communicated with the first cavity; after the power device disconnects the conductive plate in the first cavity under the drive of the excitation device, it can squeeze one end of the slider extending into the first cavity to drive the slider to disconnect the conductive plate in the second cavity.

2. The step-by-step disconnecting double-break excitation fuse according to claim 1, characterized in that the position of the conductive plate subjected to the impact of the power device and the slider is the weak disconnecting point.

3. The step-by-step disconnecting double-break excitation fuse according to claim 2, characterized in that sharp structures are arranged at the corresponding positions of the power device and the slider where they impact the weak disconnecting point of the conductive plate.

4. The step-by-step disconnecting double-break excitation fuse according to claim 3, characterized in that the slider is an arc-shaped slider, and the second cavity has an arc-shaped surface for the arc-shaped slider to fit and slide.

5. The step-by-step disconnecting double-break excitation fuse according to claim 2, characterized in that bending weak points corresponding to the weak disconnecting point are respectively formed on the conductive plates in the first cavity and the second cavity.

6. The step-by-step disconnecting double-break excitation fuse according to claim 2, characterized in that at least one fuse element is connected in parallel on the conductive plate.

7. The step-by-step disconnecting double-break excitation fuse according to claim 6, characterized in that both ends of the fuse element are respectively located on both sides of the weak disconnecting point on the conductive plate in the first cavity.

8. The step-by-step disconnecting double-break excitation fuse according to claim 6, characterized in that both ends of the fuse element are respectively located on both sides of the weak disconnecting points of the conductive plates in the first cavity and the second cavity.

9. The step-by-step disconnecting double-break excitation fuse according to any one of claims 6 to 8, characterized in that an arc extinguishing chamber filled with arc extinguishing medium is formed on the housing; the narrow diameter part of the fuse element is arranged in the arc extinguishing medium.

10. The step-by-step disconnecting double-break excitation fuse according to claim 1, characterized in that the conductive plate and the housing, and the power device and the first cavity are in sealed contact.

11. A power distribution unit, or an energy storage device, or a new energy vehicle, which applies the excitation fuse according to any one of the above claims.

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