An excitation fuse module with controllable high-speed breaking in the full current range and its breaking method

Abstract

An excitation fuse module with controllable high-speed breaking in the full current range and its breaking method, including a housing and a conductive plate passing through the housing. At least three groups of corresponding accommodation cavities are respectively arranged at intervals in the housing on both sides of the conductive plate; in each accommodation cavity on one side of the conductive plate, a piston and an excitation source are sequentially arranged; the excitation sources are respectively connected to a control board arranged in the housing; one of the accommodation cavities on the other side of the conductive plate is empty, and arc extinguishing media are respectively arranged at the bottoms of the remaining accommodation cavities, and a fuse body parallel to the conductive plate is arranged through the arc extinguishing media; the breaking current ranges of the fuse bodies are different; a weak point is arranged on the conductive plate at the position of the accommodation cavity; when the excitation source drives the piston to move, the piston can break the conductive plate at the weak point of the conductive plate. The invention can achieve rapid breaking in the full current range, and has a small volume and a light weight.

Description

Technical Field

[0001] The present invention relates to the fields of power control and electric vehicles, and particularly to an excitation fuse module capable of quickly breaking in the full current range and a breaking method thereof through 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, selecting a fuse with a low current rating cannot meet the situation of short-term 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, the output current in the case of a short circuit 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 and catching fire. Since the melting due to current-carrying heat and breaking current heat both originate from 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-term overload / impact current (such as the short-term 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] In addition, the 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 catches fire and ultimately damages the vehicle.

[0004] Currently, there is already a quick-breaking cut-off opening structure (i.e., an excitation fuse) on the market, which mainly includes a gas generating device, a conductive terminal, and a receiving cavity for the conductive terminal to fall into after dropping. The gas generating device generates high-pressure gas to drive the piston 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. However, it still has some deficiencies and defects, such as insufficient arc extinguishing ability.

[0005] Generally speaking, the main deficiencies are as follows:

[0006] 1. A fuse is only suitable for fusing within a certain range of fault currents. When the fault current is less than this current range, it cannot be fused and must reach more than 3 times the rated current to operate, and it cannot achieve full-range current disconnection.

[0007] 2. In the case of high current and high voltage, the overall size of the fuse is relatively large, and it cannot meet the application environment with high requirements for size and weight.

[0008] 3. The fuse has poor resistance to current impact. The narrow diameter of the fuse element is very narrow and cannot withstand long-term and multiple high-current impacts, and is easily melted by the impact current.

[0009] 4. If the fuse is used for too long, the fuse element may change its characteristics due to oxidation or high temperature during operation.

[0010] 5. Generally, the fuse has a relatively large internal resistance, high ineffective thermal power loss during normal operation, large heat, and high temperature.

[0011] 6. The excitation fuse that only relies on air to extinguish the arc cannot achieve effective breaking in the case of high current such as 10KA, and the excitation fuse that only relies on parallel fuse elements to extinguish the arc cannot achieve zero-current breaking.

[0012] Based on the above deficiencies, the present invention aims to develop an excitation fuse module that can meet fast breaking within the full current range to solve some deficiencies of existing thermal fuses and excitation fuses. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide an excitation fuse module that can meet fast breaking within the full current range and has better electrical performance.

[0014] To solve the above technical problem, the technical solution provided by the present invention is an excitation fuse module with controllable high-speed breaking within the full current range, including a housing and a conductive plate passing through the housing. It is characterized in that at least three groups of accommodation cavities are respectively arranged at intervals in the housing on both sides of the conductive plate. When the conductive plate is disconnected at the accommodation cavity, the accommodation cavities on both sides of the conductive plate can be communicated; in each accommodation cavity on one side of the conductive plate, a piston and an excitation source are sequentially arranged; the excitation sources are respectively connected to a control board arranged in the housing; one of the accommodation cavities on the other side of the conductive plate is empty, and arc extinguishing media are respectively arranged at the bottoms of the remaining accommodation cavities, and a fuse element parallel to the conductive plate is arranged through the arc extinguishing media; the breaking current ranges of the fuse elements are different; a weak part is arranged on the conductive plate at the position of the accommodation cavity; when the excitation source drives the piston to move, the piston can disconnect the conductive plate at the weak part of the conductive plate.

[0015] A tube shell is arranged in the accommodation cavity, the arc extinguishing medium is arranged in the tube shell, and the fuse element is arranged through the arc extinguishing medium of the tube shell.

[0016] The weak part of the conductive plate is a fracture notch that penetrates the width of the conductive plate and is opened on the conductive plate.

[0017] The fracture notch is a U-shaped, V-shaped or combined groove opened on one or both sides of the conductive plate.

[0018] The present invention also provides a breaking method for an excitation fuse module with controllable high-speed breaking in the full current range. When the fault current is low and no auxiliary arc extinguishing is required during breaking, the control board controls the excitation source corresponding to the accommodating cavity without the fuse element to act, driving the piston to disconnect the conductive plate at the accommodating cavity without the fuse element, and then the control board controls other excitation sources to act simultaneously to disconnect the conductive plates at the accommodating cavities with the fuse elements respectively; when the fault current is large and auxiliary arc extinguishing is required during breaking, the control board controls the excitation source corresponding to the accommodating cavity where the fuse element whose breaking current range includes the fault current is located to act, driving the piston to disconnect the conductive plate at the accommodating cavity where the fuse element is located; then the control board controls the excitation source corresponding to the accommodating cavity without the fuse element to act, driving the piston to disconnect the conductive plate at the accommodating cavity without the fuse element; subsequently, the control board controls the excitation sources corresponding to the accommodating cavities where other fuse elements are located to act to disconnect the conductive plates at these accommodating cavities.

[0019] The excitation fuse module of the present invention disconnects the conductive plate successively through the excitation source, forming multiple breaking points on the conductive plate, realizing rapid circuit breaking in the full current range, even zero-current breaking. At the same time, according to the parallel arc extinguishing fuse elements, when the fault current is large, better arc extinguishing and breaking can be achieved through the arc extinguishing fuse elements. And since under normal circumstances, the current almost all conducts through the conductive plate, it will not cause adverse effects on the fuse element. Only when breaking is required, first, the conductive plate is disconnected. Due to the instantaneous increase and then rapid fusing of the current at the fuse element, it can play an auxiliary arc extinguishing role, ensuring the reliability of breaking; since almost all components except the conductive plate are injection molded parts, it can be assembled quickly. At the same time, components such as the piston, conductive plate, and control board can be recycled. Due to the injection molded parts, the processing is convenient, and the spatial arrangement of each accommodating cavity improves the space utilization rate, reducing the volume and weight of the fuse module. Description of the Drawings

[0020] Figure 1 , Longitudinal sectional structure schematic diagram of the excitation fuse module of the present invention.

[0021] Figure 2 , Cross-sectional structure schematic diagram after the fault current is broken.

[0022] Figure 3 , Cross-sectional structure schematic diagram after the fault current is broken.

[0023] Figure 4 , Cross-sectional structure schematic diagram after the fault current is broken.

[0024] Figure 5 , Structural schematic diagram of the arrangement of multiple accommodating cavities with excitation sources placed therein. Detailed Embodiments

[0025] For the above technical solutions, embodiments are now given and specifically described in conjunction with the drawings. The excitation fuse module of the present invention mainly includes an upper housing, a conductive plate, a lower housing, an excitation source, a control board, a gland, etc. See Figure 1 , wherein.

[0026] The upper housing 1 and the lower housing 2 form the housing of the excitation fuse module, and a conductive plate 3 is penetrated between the upper housing 1 and the lower housing 2. A plurality of corresponding through accommodation cavities are spaced apart on the upper housing 1 and the lower housing 2, and the conductive plate penetrates through the contact surface of the accommodation cavities of the upper housing and the lower housing. In this embodiment, there are three accommodation cavities in total, which are arranged at intervals in sequence. Melts (24, 25) are respectively arranged in two adjacent accommodation cavities of the lower housing, and the melts (24, 25) are respectively connected in parallel with the conductive plate 3. A tube shell 26 is arranged at the bottom of the accommodation cavity, and the melts 24 and 25 respectively penetrate through the tube shell 26, and both ends are located outside the tube shell. Both ends of the melts 24 and 25 respectively extend upward along the side wall of the accommodation cavity and are connected in parallel with the conductive plate. An arc extinguishing medium is arranged in the tube shell 26. The arc extinguishing medium can also be directly arranged at the bottom of the accommodation cavity and then sealed with a sealing cover. With this melt tube shell structure, a simple arc extinguishing fuse can be made in advance according to the size of the accommodation cavity, including the tube shell, the melt, etc. During assembly, the simple arc extinguishing fuse is placed at the bottom of the accommodation cavity, and then both ends of the melt are connected to the conductive plate. This can facilitate assembly.

[0027] The connection method between the melt and the conductive plate is that both ends of the melts (24, 25) respectively extend upward along the side wall of the accommodation cavity where they are located and then are bent and lapped on the upper end surface of the side wall of the accommodation cavity, and the conductive plate is pressed on both ends of the melt to achieve the parallel connection between the conductive plate and the melt. To ensure the effectiveness of the connection, the melt and the conductive plate can be connected by means such as conductive adhesive, welding, etc. The melts 24 and 25 placed in different accommodation cavities have different specifications according to the magnitude of the fusing current. Therefore, the melt 24 is a large-current melt and the melt 25 is a small-current melt, and the breaking currents of the melts 24 and 25 have an overlapping part. The functions of the melts 24 and 25 are for auxiliary arc extinguishing.

[0028] Weak points that are easy to break are respectively arranged on the conductive plate at each accommodation cavity of the lower housing. In this embodiment, the weak points (31, 32, 33) of the conductive plate corresponding to each accommodation cavity. In order for the conductive plate to fall smoothly into the accommodation cavity below it after breaking, corresponding rotating notches (34, 35, 36) are respectively arranged corresponding to each weak point, so that the conductive plate part at each accommodation cavity can be broken from the weak point under the impact of the piston, and then rotate along a circular arc trajectory with the rotating notch as the center and fall into the accommodation cavity below it from the breaking point. The weak point and the rotating notch can be arranged on one or both sides of the conductive plate and penetrate the width of the conductive plate, and the structure can be U, V or other structures.

[0029] In the accommodating cavity of the upper housing 1, an excitation source (11, 12, 13) and a piston (14, 15, 16) are respectively arranged from top to bottom in sequence. The excitation sources are respectively fixed to the upper part of the accommodating cavity where they are located, and the fixing method only needs to satisfy fixing them. Vertical limiting chutes (not shown) that penetrate to the contact surface where the upper housing contacts the lower housing are respectively provided on the cavity walls of each accommodating cavity. Fixed sliders (not shown) that can be embedded in the limiting chutes are provided on the pistons. The fixed sliders of the pistons are located in the limiting chutes, which can ensure that when the pistons are impacted by external forces, they can vertically displace along the limiting chutes and will not rotate in the accommodating cavity. In order to ensure the initial position of the pistons when not impacted by external forces, a limiting device is provided in the pistons and the accommodating cavities where they are located. The limiting device can be protrusions provided on one or both opposite sides of the outer peripheral wall of the piston, and corresponding grooves are provided on the cavity walls of the accommodating cavity. The protrusions on the piston are embedded in the grooves on the cavity walls of the accommodating cavity to achieve limiting. The limiting device satisfies that when the pistons are impacted by the external forces of the excitation sources, they can break open the limiting device under the action of the external forces and perform vertical displacement.

[0030] The lower end of each piston in each accommodating cavity is directly opposite to the weak opening on the conductive plate located below it. When the piston is driven by the external force emitted by the excitation source, it can break the weak opening of the conductive plate directly below it, causing the fracture of the conductive plate at that place to fall into the accommodating cavity of the corresponding lower housing. After the upper housing, the conductive plate, and the lower housing are assembled, the accommodating cavities in the upper housing and the accommodating cavities in the lower housing are not connected to each other, which can ensure that when the pistons in each accommodating cavity act, they will not affect each other and will not cause the weak openings of the conductive plates at other accommodating cavities to break.

[0031] A control board 4 is covered on the upper end surface of the upper housing, and it is a PCB printed circuit board. Each excitation source is respectively connected to the control board 4. The external control system is provided with a current detection device, which can control the corresponding excitation source to act according to the detected current magnitude. The control board can be connected to the external control system to receive excitation signals. Usually, the excitation source corresponding to the accommodating cavity without a parallel fuse has the smallest breaking current. When the breaking current is small, the arc generated by it can be extinguished through air or other arc extinguishing media. Therefore, an auxiliary arc extinguishing fuse is not required in this accommodating cavity to extinguish the arc. When the breaking current is large, according to the breaking current of the parallel fuse on the conductive plate, the corresponding excitation source is triggered to act preferentially.

[0032] A cover plate 5 is provided on the control board 4. The upper housing is sealed through the cover plate 5, and at the same time, the control board is fixed.

[0033] In the above embodiment, the accommodating cavities of the upper housing and the lower housing are arranged at intervals in sequence. When there are many cavities, this structure may cause the excitation fuse module to be relatively large in volume and not compact enough. Therefore, the accommodating cavities of the upper housing and the lower housing can also be arranged according to Figure 5The structure has accommodation cavities respectively opened in four parts A, B, C, and D, and is arranged in a two-row spaced arrangement.

[0034] The housing in the above embodiment is divided into an upper housing structure and a lower housing structure. In a specific implementation, the housing can also be divided into a left-right housing assembly structure.

[0035] In the present invention, except for the conductive plate, the upper housing, the lower housing, the piston, the cover plate, etc. can all be injection molded bodies, and the control board is a PCB printed circuit board. With such a structure, it is simple to manufacture, light in weight, and convenient to assemble.

[0036] The working principle of this excitation fuse module: First, taking the Figure 1 structure as an example, there are three pre-breaking ports on the conductive plate from right to left, namely weak port 33, weak port 32, and weak port 31. The melt connected in parallel at weak port 33 is a small melt, used to break general fault currents (such as fault currents of 2KA - 5KA); the melt connected in parallel at weak port 32 is a large melt, used to break large fault currents (such as fault currents of 5KA - 12KA or more); there is no melt connected in parallel at weak port 31, which is an air breaking port relying on air arc extinguishing, used to break smaller fault currents (such as currents below 2KA), and achieve zero-current interruption. The control board can control the sequence of the excitation source triggering actions according to the magnitude of the fault current, and then control the sequence of the conductive plate break ports to disconnect. In short, when the fault current is large and auxiliary arc extinguishing is required during breaking, the control board controls the conductive plate with the melt for arc extinguishing connected in parallel to disconnect first, then disconnect the conductive plate without the melt connected in parallel, and finally disconnect the conductive plate with the other melt connected in parallel.

[0037] When the excitation fuse module of the present invention is connected to the circuit, during normal use, such as when an electric vehicle is driving normally, it is equivalent to a low-resistance conductor, enabling the circuit to work normally.

[0038] When a fault current appears, the external control system sends a disconnection command signal to the control board 4. The control board sends signals to the excitation source in sequence according to the detected current threshold to make it trigger and act. A large amount of high-pressure gas is immediately generated in the excitation source and expands downward, thereby pushing the 3 pistons to move downward in sequence, cutting the conductor at several weak points of the conductive plate to generate break ports. An arc is quickly generated at the break ports. The break ports with the melt connected in parallel can rely on the melt for arc extinguishing, and the break ports without the melt connected in parallel can rely on air for arc extinguishing. Finally, the arc is extinguished and the circuit is disconnected. Thus, the fault current is cut off, completing the protection of the system circuit.

[0039] Specifically: When a relatively small fault current (such as a current below 2KA) appears, refer to Figure 2, the control board controls the excitation source 11 to trigger an action, releasing high-pressure gas to push the piston 14 downward to cut off the conductive plate from the weak point 31 of the conductive plate. An arc is quickly generated at the break. Since the fault current is small, the generated arc is also small. Therefore, the arc at this break gradually extinguishes in the air, successfully cutting off the fault current. Then, the control board controls the excitation sources (12, 13) to trigger actions in sequence, driving the pistons (15, 16) to impact the conductive plate to form multiple breaks on the conductive plate. At this time, the fuses (24, 25) are not melted, which is convenient for subsequent module recycling and waste treatment.

[0040] When a general fault current (such as a current of 2KA - 5KA) appears, during the breaking of the fault current within this range, auxiliary arc extinguishing is required. Refer to Figure 3 , the control board controls the excitation source 13 to trigger an action, releasing high-pressure gas to push the piston 16 downward to cut off the conductive plate from the weak point 33 of the conductive plate. An arc is quickly generated at the break. The shunt small-current fuse also melts under the high temperature generated by the suddenly increasing current for arc extinguishing to ensure the reliability of breaking; after the control board triggers the excitation source 13, the control board then controls the excitation source 11 to trigger an action to drive the piston 14 to cut off the conductive plate at the weak point 31 of the conductive plate to break the conductive plate, helping to form a physical break to ensure the cutting off of the circuit; then the control board controls the excitation source 12 to trigger an action to drive the piston 15 to cut off the conductive plate, which is convenient for subsequent module recycling and waste treatment.

[0041] When a large fault current (such as a current of 5KA - 12KA) appears, during the breaking of the fault current within this range, auxiliary arc extinguishing is required. Refer to Figure 4 , the control board preferentially controls the excitation source 12 to trigger an action, releasing high-pressure gas to push the piston 15 downward to cut off the conductive plate from the weak point 32 of the conductive plate. An arc is quickly generated at the break. The shunt large-current fuse and the arc extinguishing medium are used for arc extinguishing; after the control board triggers the excitation source 12, the control board then controls the excitation source 11 to trigger an action to drive the piston 14 to cut off the conductive plate at the weak point 31 of the conductive plate to break the conductive plate, helping to form a physical break to ensure the cutting off of the circuit; then the control board controls the excitation source 13 to trigger an action to drive the piston 16 to cut off the conductive plate, which is convenient for subsequent module recycling and waste treatment.

[0042] The excitation fuse module of the present invention, compared with traditional fuses or excitation fuses, can be quickly broken within the full current range; and it is small in size, light in weight, convenient for assembly, and easy to recycle.

Claims

1. A controllable full-current-range high-speed breaking excitation fuse module, comprising a housing and a conductive plate passing through the housing, characterized in that at least three groups of accommodating cavities are respectively and spacedly arranged in the housing on both sides of the conductive plate. After the conductive plate is disconnected at the accommodating cavity, the accommodating cavities on both sides of the conductive plate can be communicated; in each accommodating cavity on one side of the conductive plate, a piston and an excitation source are sequentially arranged; the excitation sources are respectively connected to a control board arranged in the housing; one of the accommodating cavities on the other side of the conductive plate is empty, and arc extinguishing media are respectively arranged at the bottoms of the remaining accommodating cavities, and a fuse body parallel to the conductive plate is arranged through the arc extinguishing media; the breaking current ranges of the fuse bodies are different; a weak part is arranged on the conductive plate at the accommodating cavity; when the excitation source drives the piston to move, the piston can disconnect the conductive plate at the weak part of the conductive plate; when the fault current is low and auxiliary arc extinguishing is not required, the control board controls the excitation source corresponding to the accommodating cavity without the fuse body to act, and drives the piston to disconnect the conductive plate at the accommodating cavity without the fuse body; then the control board controls the other excitation sources to act simultaneously, and disconnects the conductive plates at the accommodating cavities provided with the fuse bodies respectively; when the fault current is large and auxiliary arc extinguishing is required during breaking, the control board controls the excitation source corresponding to the accommodating cavity where the fuse body with a breaking current range covering the fault current is located to act, and drives the piston to disconnect the conductive plate at the accommodating cavity where the fuse body is located; then the control board controls the excitation source corresponding to the accommodating cavity without the fuse body to act, and drives the piston to disconnect the conductive plate at the accommodating cavity without the fuse body; subsequently, the control board controls the excitation sources corresponding to the accommodating cavities where the other fuse bodies are located to act to disconnect the conductive plates at these accommodating cavities.

2. The controllable full-current-range high-speed breaking excitation fuse module according to claim 1, characterized in that a tube shell is arranged in the accommodating cavity, the arc extinguishing medium is arranged in the tube shell, and the fuse body is arranged through the arc extinguishing medium in the tube shell.

3. The controllable full-current-range high-speed breaking excitation fuse module according to claim 1, characterized in that the weak part of the conductive plate is a fracture notch opened on the conductive plate and penetrating the width of the conductive plate.

4. The controllable full-current-range high-speed breaking excitation fuse module according to claim 3, characterized in that the fracture notch is a U-shaped, V-shaped or combined groove opened on one or both sides of the conductive plate.

5. The controllable full-current-range high-speed breaking excitation fuse module according to claim 1, characterized in that the housing and the piston are integrally formed by injection molding.

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