A multi-break excitation fuse with a rotating structure

Abstract

A multi-break excitation fuse adopting a rotating structure comprises a shell, a conductive plate inserted in the shell, and a gas generating device and a piston arranged above the conductive plate from top to bottom. Arc-shaped grooves are respectively opened on the shell at both ends of the length direction of the conductive plate in the shell; disconnection weak points are respectively arranged at the center of the conductive plate in the shell and at the conductive plate at the circular arc-shaped grooves on both sides; rotating support blocks that can be displaced along the circular arc-shaped grooves are respectively fixedly arranged under the conductive plate between the disconnection weak points; the impact end of the piston faces the disconnection weak point in the center of the conductive plate. The excitation fuse of the present invention improves the breaking capacity and arc extinguishing capacity.

Description

Technical Field

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

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

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

[0004] At present, there is a fast-breaking cut-off opening structure on the market, which mainly includes a gas generating device, a conductive plate and a receiving chamber after the conductive plate falls. The gas generating device generates high-pressure gas to drive the piston to break the conductive plate, and the conductive plate falls downward into the receiving chamber after breaking, so as to achieve the purpose of fast circuit disconnection. However, it still has some shortcomings and defects, resulting in limited arc extinguishing ability: due to the single-break, the arc extinguishing ability is low, and it is difficult to disconnect large fault currents. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an excitation fuse with multiple breaks, by which the arc extinguishing capability and the breaking capability are improved.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is a multi-break excitation fuse with a rotating structure, comprising a shell, a conductive plate inserted in the shell, and a gas generating device and a piston arranged above the conductive plate from top to bottom, characterized in that circular arc grooves are respectively opened on the shell at both ends of the length direction of the conductive plate in the shell; disconnection weak points are respectively provided at the center of the conductive plate located in the shell and at the conductive plate located at the circular arc groove; rotating support blocks that can be displaced along the circular arc groove are respectively fixedly provided under the conductive plate between the disconnection weak points; the impact end of the piston is opposite to the disconnection weak point in the center of the conductive plate; when disconnected, the rotating support block can drive the conductive plate part located above it to move into the circular arc groove.

[0007] A cavity is provided on the shell body facing the piston below the conductive plate; when the piston moves downward to the dead point, the rotating support block and the conductive plate portion fixed thereon after being disconnected can move into the arc-shaped groove; the impact end of the piston is interference-fitted in the facing cavity.

[0008] Arc extinguishing chambers may be arranged on both sides of the cavity; the arc extinguishing chambers may be filled with arc extinguishing medium.

[0009] Both ends of the rotating support block along the width direction of the conductive plate are fixed on the housing through a rotating shaft.

[0010] The disconnection weak point is a disconnection notch.

[0011] The disconnection notch is arranged on one side or both upper and lower sides of the conductive plate; the disconnection notch is in a U-shaped, V-shaped or a combination thereof.

[0012] The shell includes a top shell, a middle shell and a lower shell; the top shell is located on the middle shell, and the conductive plate is located between the contact surfaces of the middle shell and the lower shell; the gas generating device is arranged in the top shell, the piston is located in the middle shell, and the arc-shaped groove is located on the inner wall of the shell composed of the middle shell and the lower shell; a pressure cylinder is sleeved on the outer periphery of the top shell and the middle shell; the cavity facing the piston below the conductive plate is located in the lower shell.

[0013] The outer peripheral surface of the portion of the rotating support block that is not combined with the conductive plate is an arc-shaped surface; the portion of the rotating support block below the conductive plate that is close to the shell wall fits in the arc-shaped groove portion below the conductive plate; when the piston moves downward to the dead point position, the rotating support block with the disconnected conductive plate portion is completely fitted in the arc-shaped groove in an interference fit manner.

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

[0015] Compared with the common excitation fuse, the excitation fuse of the present invention has the following advantages:

[0016] 1. The breaking capacity of the single-break excitation fuse is about 8KA, and the breaking voltage is 400VDC; while the breaking capacity of the multi-break excitation fuse product with a rotating structure is about 16KA, and the breaking voltage is 1000VDC. The breaking capacity and breaking voltage of this product are significantly improved.

[0017] 2. The arc extinguishing time of the single-break excitation fuse is about 0.6ms; while the arc extinguishing time of the multi-break excitation fuse product with a rotating structure is about 0.4ms, which significantly improves the arc extinguishing ability and shortens the arc extinguishing time.

[0018] 3. Compared with single-break excitation fuses, multi-break excitation fuses with a rotating structure have the same weight and volume, and no significant increase in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 , schematic diagram of the cross-sectional structure of the excitation fuse before disconnection in Example 1.

[0020] Figure 2 , schematic diagram of the cross-sectional structure of the excitation fuse after disconnection in Example 1.

[0021] Figure 3 , schematic diagram of the cross-sectional structure of embodiment 2 before the excitation fuse is disconnected.

[0022] Figure 4 , schematic diagram of the cross-sectional structure of the excitation fuse after disconnection in Example 21. DETAILED DESCRIPTION

[0023] With respect to the above technical solution, embodiments are given and specifically described with reference to the drawings.

[0024] Example 1

[0025] The excitation fuse includes a housing, a conductive plate, an excitation device, and a breaking device, wherein:

[0026] Housing, see Figure 1 and Figure 2 , comprising an upper shell 1 and a lower shell 2, with a conductive plate 3 disposed between the upper shell and the lower shell. Figure 1 and Figure 2, a sealing device is provided between the contact surfaces of the upper shell and the lower shell. A cavity is provided on the upper shell, which passes through the upper and lower ends, and a limiting step is provided in the upper part of the cavity of the upper shell. The excitation device 4 is placed on the limiting step in the upper part of the cavity of the upper shell, and the excitation device is limited. Then, the excitation device is pressed by a pressing plate or a pressing sleeve (not shown) and set in the cavity. In this embodiment, the excitation device is a gas generator, which can receive a signal from the outside, ignite and release high-pressure gas as a driving force.

[0027] A piston 5 is arranged in the cavity below the gas generator. In the original position, the piston 5 is fixed in the cavity by a limiting device. The limiting device is a protrusion arranged on the piston, and a groove is arranged at a corresponding position on the cavity wall, and the protrusion on the piston is embedded in the groove to achieve limiting. In order to allow the piston to move more smoothly after the limiting device is overcome by an external force, vertical slide grooves are respectively opened on the shell wall of the cavity where the lower end of the piston is located, and a slider that can protrude from the piston body is arranged at the position of the slide groove corresponding to the lower end of the piston, and the slider is arranged in the slide groove. When the piston overcomes the limiting device, it can move downward smoothly along the slide groove to impact and disconnect the conductive plate.

[0028] The punch 51 on the piston is a blade-like structure for conveniently cutting the conductive plate. The piston punch structure can also be an inverted cone or other structure that is easy to cut the conductive plate. When driven by the exciter, the piston can break through the limit device and move downward along the cavity. The opening end of the upper shell cavity at the conductive plate is an enlarged notch.

[0029] A symmetrical enlarged notch is provided on the lower shell below the conductive plate at a position corresponding to the enlarged notch of the upper shell. After the upper shell, the lower shell and the conductive plate are assembled, a circular arc groove can be formed on the side walls of the upper and lower shells along the length direction of the conductive plate. A disconnection notch 301 that runs through the width of the conductive plate is provided at the center of the cavity formed by the upper and lower shells where the conductive plate is located, and disconnection notches 302 are symmetrically provided at positions close to the shell wall in the cavity formed by the upper and lower shells where the conductive plate is located. Support blocks 303 with arc structures are respectively fixedly provided under the conductive plate between the disconnection notch 301 and the disconnection notch 302, and the curvature of the support block 303 is the same as that of the circular arc groove. The bottom of the support block 303 is located at the bottom of the circular arc groove near the conductive plate, and a part of the support block 303 fits on the concave surface of the enlarged notch of the lower shell. When the conductive plate is disconnected, under the forced impact of the piston, the support block 303 can slide along the arc-shaped groove with the disconnected conductive plate part to fill the arc-shaped groove, and completely disconnect from the external circuit.

[0030] A cavity 21 is provided on the lower shell below the support block 303, and an arc extinguishing medium can be provided in the cavity 21, which is conducive to arc extinguishing. A cavity 22 is provided on the lower shell directly below the piston punch, and the cross-sectional shape of the cavity is the same as that of the piston punch. When the conductive plate is disconnected, when the piston continues to move downward to the dead point position, the piston punch will enter the cavity 22 in an interference fit manner, forming two interference lines on the left and right, squeezing the arc, and being able to cut off any residual arc again.

[0031] The contact surfaces between the upper shell and the lower shell, and between the piston and the upper shell cavity of the structure are sealed. The upper shell, the lower shell, the piston, and the support block are all made of insulating materials and can be manufactured by injection molding, buried mold and other processes.

[0032] Example 2

[0033] See also Figure 3 to Figure 4 The difference from the fuse structure of Example 1 is that the upper shell is composed of a top shell 6 and a middle shell 7 which are arranged from top to bottom in sequence, and the top shell and the middle shell are connected by threads.

[0034] The excitation device 4 is arranged in the accommodating cavity of the top shell, and the piston 5 is accommodated in the cavity of the middle shell. A pressure cylinder 8 is sleeved on the outer periphery of the top shell and the middle shell. The pressure cylinder 8 is made of metal material, and fixes the excitation device, the top shell and the middle shell. The pressure cylinder 8 is fixed on the middle shell. The impact end of the punch 51 of the piston 5 is a conical structure. The conductive plate 3 is arranged between the middle shell and the lower shell. The front and rear ends of the support block 303 fixedly arranged under the conductive plate, that is, the two ends located in the width direction of the conductive plate, are fixed to the middle shell through a rotating shaft, and the rotating support block can rotate along the rotating shaft. A cavity for the piston punch to move downward is opened on the lower shell opposite to the impact end of the piston punch. When the piston reaches the dead point, the piston punch and the cavity of the lower shell are interference fit to form two interference lines on the left and right, which squeeze the arc and can cut off the possible residual arc again.

[0035] In the above two embodiments, the contacts between the housings and between the piston and the housing are all sealed contacts, that is, a sealing device 9 is provided at each contact surface.

[0036] The working principle of the above embodiment is as follows:

[0037] Normal current flow state: The current flows through the two ends of the conductive plate connected in series on the main circuit of the battery pack, and the product can be regarded as a conductor.

[0038] Circuit disconnection operation: The gas generator receives a disconnection signal from the outside, ignites and explodes in a short time to produce high-pressure gas. The high-pressure gas pushes the piston to break through the limit structure and move downward. The piston cuts the conductor at the weak point in the middle of the conductive plate to form an air fracture. At the same time, it begins to push the conductive plate and the rotating support block assembly to rotate outward. The fractures on both sides of the fracture in the middle of the conductive plate are also disconnected as the rotating support block and the conductive plate are forced to rotate to form three fractures. As the piston continues to move downward, the three fractures gradually open up. As the piston moves into place, the rotating support block rotates 90° into place, the three fractures are fully opened, the current is cut off, and the circuit is completely disconnected.

[0039] The arc extinguishing principle is as follows:

[0040] During the rotation of the rotating assembly of the conductive plate and the rotating support block, the piston squeezes the rotating assembly, so that the rotating support block and the arc-shaped groove on the shell form an interference fit, and the arc is cut off. When the arc is extinguished, the multiple fractures divide the arc into multiple small arc segments in series. The multiple fractures lengthen the total length of the arc, and the speed at which the arc is elongated increases exponentially, which is conducive to the cooling, recombination and diffusion of the arc, accelerates the increase of the arc gap resistance, improves the recovery speed of the dielectric strength, and shortens the arc extinguishing time. After the disconnection, the rotation of the left and right conductive plates and the rotating support block squeezes the circular arc groove to form a slit. Since the arc moves in the solid slit, on the one hand, it is cooled and the deionization effect is enhanced; on the other hand, the arc is elongated, the arc diameter is compressed, and the arc resistance increases, which prompts the arc to extinguish.

[0041] At the same time, when the piston moves to the dead point, the punch and the cavity of the lower shell are interference fit to form two left and right interference lines, which squeeze the arc and cut off any residual arc again.

[0042] The excitation fuse of the present invention can generate multiple fractures, realize efficient arc extinguishing, and improve the arc extinguishing capacity and breaking capacity.

Claims

1. A multi-break excitation fuse with a rotating structure, comprising a housing, a conductive plate inserted in the housing, and a gas generating device and a piston arranged above the conductive plate from top to bottom, characterized in that: Arc-shaped grooves are respectively provided on the shell at both ends of the length direction of the conductive plate in the shell; disconnection weak points are respectively provided at the central part of the conductive plate located in the shell and at the conductive plate located at the arc-shaped groove; rotating support blocks that can be displaced along the arc-shaped groove are respectively fixedly provided under the conductive plate between the disconnection weak points; the outer peripheral surface of the part of the rotating support block that is not combined with the conductive plate is an arc-shaped surface; the impact end of the piston is directly facing the disconnection weak point in the center of the conductive plate; when disconnecting, the impact end of the piston disconnects the conductive plate from the disconnection weak point, and the piston drives the rotating support block and the conductive plate part located thereon to displace into the arc-shaped groove.

2. The multi-break excitation fuse with a rotating structure according to claim 1 is characterized in that: A cavity is provided on the shell body facing the piston below the conductive plate; when the piston moves downward to the dead point, the rotating support block and the conductive plate portion fixed thereon after being disconnected can move into the arc-shaped groove; the impact end of the piston is interference-fitted in the facing cavity.

3. The multi-break excitation fuse with a rotating structure according to claim 2, characterized in that: Arc extinguishing chambers may be arranged on both sides of the cavity; the arc extinguishing chambers may be filled with arc extinguishing medium.

4. The multi-break excitation fuse with a rotating structure according to claim 1, characterized in that: Both ends of the rotating support block along the width direction of the conductive plate are fixed on the housing through a rotating shaft.

5. The multi-break excitation fuse with a rotating structure according to claim 1, characterized in that: The disconnection weak point is a disconnection notch.

6. The multi-break excitation fuse with a rotating structure according to claim 5, characterized in that: The disconnection notch is arranged on one side or both upper and lower sides of the conductive plate; the disconnection notch is in a U-shaped, V-shaped or a combination thereof.

7. The multi-break excitation fuse with a rotating structure according to claim 1, characterized in that: The shell includes a top shell, a middle shell and a lower shell; the top shell is located on the middle shell, and the conductive plate is located between the contact surfaces of the middle shell and the lower shell; the gas generating device is arranged in the top shell, the piston is located in the middle shell, and the arc-shaped groove is located on the inner wall of the shell composed of the middle shell and the lower shell; a pressure cylinder is sleeved on the outer periphery of the top shell and the middle shell; the cavity facing the piston below the conductive plate is located in the lower shell.

8. The multi-break excitation fuse with a rotating structure according to claim 1, characterized in that: The portion of the rotating support block under the conductive plate close to the shell wall fits in the arc-shaped groove portion under the conductive plate; when the piston moves downward to the dead point position, the rotating support block with the disconnected conductive plate portion is completely fitted in the arc-shaped groove in an interference fit manner.

9. The multi-break excitation fuse with a rotating structure according to any one of claims 1 to 8, characterized in that: Apply it in distribution units, energy storage equipment, or new energy vehicles.

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