Circuit protection device
By using a design that connects the first and second fuses in parallel and series in the circuit protection device, combined with the actuator and mechanical structure, rapid circuit protection under low and high abnormal current conditions is achieved, improving the system's reliability and response speed.
Patent Information
- Application Number
- CN202511352157.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-19
- Publication Date
- 2025-11-21
AI Technical Summary
Under low and high abnormal current conditions, existing excitation fuses may fail to melt in time or have an excessively long melting time, resulting in the circuit not being able to be completely disconnected in time, leading to insufficient system reliability.
The system employs a parallel arc-extinguishing branch with first and second fusible elements connected in series. The first fusible element melts first under low-multiplier abnormal current, while the second fusible element melts under high-multiplier abnormal current. Combined with the actuator and mechanical structure, this achieves rapid circuit protection.
Under abnormal current conditions across the entire range, the circuit protection device has a fast response speed and high system reliability, avoiding the contradiction of a single molten element being sluggish at low magnification or exploding at high magnification, and is suitable for abnormal current scenarios across the entire range.
Smart Images
Figure CN120999520A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of low-voltage electrical apparatus, in particular to a circuit protection device. BACKGROUND
[0002] At present, the protection device of the battery pack of an electric vehicle mostly adopts a traditional thermal fuse. In order to improve the protection speed, the industry proposes an incentive fuse as a new generation of solution. The incentive fuse can drive an insulator to cut off a conductor in a very short time and rapidly form a physical break by virtue of an electronic gas generating device, and its protection response speed has realized a qualitative leap compared with the traditional thermal fuse.
[0003] At present, the incentive fuse mostly adopts a parallel fuse structure to realize auxiliary arc extinguishing, and the core working logic is as follows: when the main circuit is disconnected for circuit protection, the fuse will be fused due to the instantaneous large current passing through the fuse of the arc extinguishing branch, so as to realize the purpose of arc extinguishing. However, in actual use, after the main circuit is disconnected, the fuse may not be fused due to some unexpected reasons, or the actual fusing time is longer than the designed fusing time, especially under the condition of low-multiple abnormal current, which leads to the fact that the entire circuit cannot be disconnected in time and completely. SUMMARY
[0004] The purpose of the present application is to provide a circuit protection device suitable for circuit protection under the conditions of low-multiple abnormal current and high-multiple abnormal current, with fast response speed and high system reliability.
[0005] The embodiment of the present application is implemented as follows:
[0006] In a first aspect of the embodiment of the present application, a circuit protection device is provided, which comprises a main circuit with a pre-break and an arc extinguishing branch connected in parallel with the main circuit at both ends of the pre-break, and at least a first fuse and a second fuse are connected in series on the arc extinguishing branch. When abnormal current passes through the main circuit, the pre-break is disconnected first, the abnormal current flows through the arc extinguishing branch, and the first fuse is fused before the second fuse. The circuit protection device is suitable for circuit protection under the conditions of low-multiple abnormal current and high-multiple abnormal current, with fast response speed and high system reliability.
[0007] As an implementable manner, the materials of the first fuse and the second fuse are the same, and the resistance of the second fuse is higher than that of the first fuse; or, the materials of the first fuse and the second fuse are different, and the melting point of the second fuse is higher than that of the first fuse.
[0008] As an implementable mode, the first melt is provided with a conductor in parallel at least at two ends, the conductor has an internal resistance smaller than that of the main circuit, and the executing element can first disconnect the pre-disconnection part, and the conductor can be disconnected by the executing element after the arc-extinguishing branch is the only one conducting.
[0009] As an implementable mode, the first melt, the second melt and the conductor are arranged in the same layer, the first melt and the conductor are arranged on one side of the second melt, and the first melt and the conductor are connected to the second melt respectively.
[0010] As an implementable mode, the first melt and the second melt are arranged in the same layer and are spaced apart, the conductor and the second melt are arranged in the same layer, and the first melt and the conductor are connected to the second melt respectively.
[0011] As an implementable mode, the first melt extends towards the second melt and has a welding part, and the first melt is integrally formed, riveted, welded or bolted with the second melt through the welding part.
[0012] As an implementable mode, the conductor and the second melt are integrally formed, riveted, welded or bolted.
[0013] As an implementable mode, the pre-disconnection part and the conductor are arranged in sequence on a movement path of the executing element, and the executing element can continue to move towards the conductor and disconnect the conductor after the pre-disconnection part is first disconnected.
[0014] As an implementable mode, an exciting element is further included, the conductor is located on a movement path of the exciting element, and the executing element can drive the exciting element to move towards the conductor to disconnect the conductor.
[0015] As an implementable mode, a mechanical structure is further included, the mechanical structure is used to lock the conductor and the second melt, and the executing element can drive the mechanical structure to unlock the conductor and the second melt to realize separation of the conductor and the second melt.
[0016] The beneficial effects of the embodiments of the application include:
[0017] The circuit protection device comprises a main circuit with a pre-break, and an arc extinguishing branch connected in parallel with the main circuit at both ends of the pre-break, and at least a first fuse and a second fuse connected in series on the arc extinguishing branch. When an abnormal current passes through the main circuit, the pre-break is first disconnected, the abnormal current flows through the arc extinguishing branch, and the first fuse is first fused than the second fuse. Compared with the prior art, the present application deals with abnormal current conditions by two fuses, only the first fuse is fused at low times, and the two fuses work together at high times, and the first fuse is first fused than the second fuse, avoiding the contradiction that a single fuse is slow at low times and explodes at high times, adapting to the full range of abnormal current scenarios, and improving system reliability. BRIEF DESCRIPTION OF DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0019] Figure 1 The structural schematic diagram of the circuit protection device provided by the embodiments of the present application is shown in the figure.
[0020] Figure 2 The structural schematic diagram of the arc extinguishing branch provided by the first embodiment of the present application is shown in the figure.
[0021] Figure 3 The structural schematic diagram of the arc extinguishing branch provided by the second embodiment of the present application is shown in the figure.
[0022] Figure 4 The structural schematic diagram of the circuit protection device provided by the first embodiment of the present application is shown in the figure.
[0023] Figure 5 The structural schematic diagram of the circuit protection device provided by the second embodiment of the present application is shown in the figure.
[0024] Figure 6 The structural schematic diagram of the circuit protection device provided by the third embodiment of the present application is shown in the figure.
[0025] Figure 7 The structural schematic diagram of the circuit protection device provided by the third embodiment of the present application is shown in the figure.
[0026] Figure: 100-circuit protection device; 10-main circuit; 11-pre-break; 20-arc extinguishing branch; 21-first fuse; 211-welding part; 22-second fuse; 23-conductor; 30-executing element; 40-actuating element; 50-mechanical structure. DETAILED DESCRIPTION
[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Similar reference numerals and letters in the following drawings represent similar items, and once an item is defined in one drawing, it does not need to be further defined in other drawings.
[0028] The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed during use, and are merely for the convenience of describing the present application and simplifying the description, and cannot be understood as a limitation on the present application. The terms "first", "second", and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.
[0029] Unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the connection inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0030] Please refer to Figures 1 to 7 The circuit protection device 100 provided by the embodiments of the present application includes a main circuit 10 with a pre-break 11, and an arc extinguishing branch 20 connected at both ends of the pre-break 11 and in parallel with the main circuit 10. The arc extinguishing branch 20 has at least a first fuse 21 and a second fuse 22 connected in series. When an abnormal current passes through the main circuit 10, the pre-break 11 is first disconnected, the abnormal current flows through the arc extinguishing branch 20, and the first fuse 21 is first fused before the second fuse 22. The circuit protection device 100 is suitable for circuit protection in low-multiple abnormal current conditions and high-multiple abnormal current conditions, has fast response speed, and has high system reliability.
[0031] It should be noted that the circuit protection device 100 includes the main circuit 10 and the arc extinguishing branch 20. The main circuit 10 is the main conduction path (such as a copper bar connecting the power supply and the load) during normal operation of the circuit, and is provided with a pre-break 11, i.e. a weak point (such as a conduction section with a smaller cross section or a disconnectable connection point). During normal operation, the pre-break 11 does not affect current transmission. During abnormal conditions, the excitation source receives an excitation signal, releases high-pressure gas, drives the execution element 30 to move towards the side close to the pre-break 11, and applies mechanical action on the pre-break 11, so as to quickly disconnect the pre-break 11, thereby realizing circuit protection of the main circuit 10.
[0032] The two ends of the arc extinguishing branch 20 are connected on both sides of the pre-break 11, forming a parallel structure of the "main circuit 10-arc extinguishing branch 20", at least two fuses are connected in series on the arc extinguishing branch 20, the rated breaking current of the first fuse 21 is low, and the first fuse 21 is easy to break under low abnormal current, the rated breaking current of the second fuse 22 is high, and the second fuse 22 is broken only under high abnormal current, the first fuse 21 and the second fuse 22 are connected in series, which ensures that the arc extinguishing branch 20 must be turned on at the same time to form a loop, and when it is broken, it acts according to different working conditions.
[0033] Under the condition of low abnormal current, the execution element 30 first cuts off the pre-break 11, the main circuit 10 is disconnected, only the arc extinguishing branch 20 is turned on, the low current reaches the rated breaking current of the first fuse 21, the first fuse 21 is first broken, the arc extinguishing branch 20 is disconnected, and the circuit is completely powered off. At this time, the second fuse 22 has a high rated breaking current, the low current does not reach the rated breaking current of the second fuse 22, and it is not enough to make it break, and only the first fuse 21 is broken to complete the circuit protection; under the condition of high abnormal current, the execution element 30 first cuts off the pre-break 11, the main circuit 10 is disconnected, only the arc extinguishing branch 20 is turned on, the high current makes the first fuse 21 melt instantaneously, and the "continuation effect" of the short-circuit current still flows through the second fuse 22, and then the second fuse 22 also melts under the action of strong current, the arc extinguishing branch 20 is disconnected, and the circuit is completely powered off.
[0034] After the traditional excitation fuse breaks the main circuit 10, the fuse may not be broken due to some unexpected reasons, or the actual breaking time is longer than the designed breaking time, especially under the condition of low abnormal current, which causes the entire circuit to be unable to be disconnected in time. The application can cope with abnormal current conditions through two fuses, only the first fuse 21 is broken under low abnormal current, and the two fuses work together under high abnormal current, and the first fuse 21 is broken before the second fuse 22, avoiding the contradiction that a single fuse is slow under low abnormal current and explodes under high abnormal current, adapting to the full range of abnormal current scenarios and improving system reliability.
[0035] As an implementable manner, the materials of the first fuse 21 and the second fuse 22 are the same, and the resistance of the second fuse 22 is higher than that of the first fuse 21; or, the materials of the first fuse 21 and the second fuse 22 are different, and the melting point of the second fuse 22 is higher than that of the first fuse 21.
[0036] It should be noted that in some embodiments, the first melt 21 and the second melt 22 are made of the same conductive material (such as red copper, copper-silver alloy), which ensures the consistency of the conductive performance and the temperature resistance. By adjusting the size of the "melt narrow diameter structure" (i.e. the minimum cross-sectional area through which the current flows), the resistance of the second melt 22 is higher than that of the first melt 21, thereby realizing the time difference of the melting. For example, the narrow diameter area of the first melt 21 is designed in a "wide and thin" form, the minimum cross-sectional area is larger, and the narrow diameter area of the second melt 22 is designed in a "narrow and thick" form, the minimum cross-sectional area is smaller, so that the resistance of the second melt 22 is higher than that of the first melt 21. When the abnormal current flows through the arc extinguishing branch 20, the first melt 21 can slowly heat up to melt at a low multiple current due to its small resistance and low heat generation rate; the second melt 22 needs a higher current or a longer time to accumulate enough heat due to its large resistance and high heat generation rate, thereby realizing the time sequence design of "the first melt 21 melts before the second melt 22".
[0037] Alternatively, in other embodiments, the first melt 21 and the second melt 22 are made of different conductive materials with different melting points, and the melting point of the second melt 22 is higher than that of the first melt 21. The difference in melting point ensures that the first melt 21 reaches the melting temperature first under the same current, without relying on resistance regulation, which is suitable for scenarios with high requirements for resistance stability (such as precision instrument power supply circuits). For example, the first melt 21 can be made of a low-melting-point material (such as a lead-tin alloy with a melting point of about 200-300°C), which is sensitive to temperature and easily melts at a low multiple abnormal current; the second melt 22 can be made of a high-melting-point material (such as a copper alloy with a melting point of about 900-1083°C), which is resistant to high temperature and melts only at a high multiple abnormal current. When the abnormal current flows through the arc extinguishing branch 20, the first melt 21 melts first at a low multiple current; at a high multiple current, after the first melt 21 melts quickly, the second melt 22 can temporarily carry the current and limit the current due to its high melting point, and then slowly melt, thereby avoiding the loss of control of the arc caused by the simultaneous melting of the two melts.
[0038] As an implementable way, as shown in Figures 1 to 7 , it further includes an execution element 30, and the two ends of the first melt 21 are connected in parallel with a conductor 23, the internal resistance of the conductor 23 is smaller than that of the main loop 10, and the execution element 30 can first disconnect the pre-break 11, and when only the arc extinguishing branch 20 is turned on, the conductor 23 can be disconnected by the execution element 30. As an implementable way, as shown in Figure 2 and Figure 3 , the conductor 23 and the second melt 22 are integrally formed, riveted, welded or bolted.
[0039] It should be noted that in the arc extinguishing branch 20, the two ends of the first fuse 21 are additionally connected in parallel with a conductor 23 (such as a copper wire or a copper sheet), and the internal resistance of the conductor 23 is much smaller than the internal resistance of the main circuit 10. In normal operation, since the internal resistance of the main circuit 10 is smaller than the internal resistance of the arc extinguishing branch 20, most of the current flows through the main circuit 10, and even if there is a small leakage current entering the arc extinguishing branch 20, it will preferentially pass through the parallel conductor 23 (the internal resistance is much smaller than the first fuse 21), and the first fuse 21 has almost no current passing through, avoiding the first fuse 21 from being heated and aged by long-term micro-current.
[0040] In the low-multiple abnormal current working condition, the executing element 30 first cuts off the pre-break 11, the main circuit 10 is disconnected, only the arc extinguishing branch 20 is turned on, and the low-multiple current flows into the arc extinguishing branch 20. Since the internal resistance of the conductor 23 is lower, most of the current flows through the conductor 23, and a small part of the current flows through the first fuse 21; although the first fuse 21 only passes through a small part of the current, its low melting point characteristic still enables the first fuse 21 to be melted and broken in a short time; after the first fuse 21 is melted and broken, the conductor 23 connected in parallel with it remains conductive, and the current flows through the "conductor 23 + second fuse 22"; at this time, the heat generated by the low-multiple current passing through the second fuse 22 is limited and is not enough to make it melt and break. The conductor 23 can be cut off by the executing element 30, so that the arc extinguishing branch 20 is disconnected, the circuit is completely powered off, and the arc extinguishing purpose is achieved.
[0041] As an implementable manner, as shown in Figure 2 The first fuse 21, the second fuse 22 and the conductor 23 are distributed in the same layer, the first fuse 21 and the conductor 23 are arranged on one side of the second fuse 22, and the first fuse 21 and the conductor 23 are connected with the second fuse 22, respectively. In this embodiment, by means of the structure design of "same layer distribution", the first fuse 21, the second fuse 22 and the conductor 23 are integrated into a compact planar unit, which not only optimizes the space utilization rate, but also ensures that the current path is short and reliable.
[0042] It should be noted that the second melt 22 extends along the length direction of the main circuit 10 as the core conductive carrier, one end of which is provided with a connection terminal for connecting the incoming line end of the arc extinguishing branch 20 (connected to one side of the pre-break 11), and the other end is connected to the first melt 21 and one end of the conductor 23, forming a current path of "one main circuit and two branches". The first melt 21 and the conductor 23 are arranged in parallel and spaced apart on the same side of the second melt 22 (e.g., the right side of the second melt 22), and the connection points of the two with the second melt 22 are arranged adjacent to each other and are kept insulated from each other to avoid short circuit. One end of the first melt 21 is fixed to the branch end of the second melt 22, and the other end extends to the outgoing line end of the arc extinguishing branch 20 (connected to the other side of the pre-break 11), forming a path of "second melt 22-first melt 21-outgoing line end"; similarly, one end of the conductor 23 is fixed to the branch end of the second melt 22, and the other end extends to the outgoing line end of the arc extinguishing branch 20, and is combined with the outgoing line end of the first melt 21, which can be directly connected to the main circuit 10, or connected to the main circuit 10 through another second melt 22, forming a parallel path of "second melt 22-conductor 23-outgoing line end-another second melt 22"; finally, the first melt 21 and the conductor 23 form "parallel branches" on the same side of the second melt 22, and the three are arranged in the same layer to form a complete arc extinguishing branch 20.
[0043] As an implementable manner, as shown in Figure 3 , the first melt 21 and the second melt 22 are arranged in layers and spaced apart, the conductor 23 and the second melt 22 are arranged in the same layer, and the first melt 21 and the conductor 23 are connected to the second melt 22. Different from the foregoing embodiment, in this embodiment, through the mixed layout of "first melt 21 and second melt 22 arranged in layers and spaced apart + conductor 23 and second melt 22 arranged in the same layer", the space is compacted, the heat conduction path is optimized by the layered structure, the current path is shortened by the same layer design, and the accuracy and reliability of the protection response are further improved by combining the parameter differences of the double melts and the shunt characteristics of the conductor 23.
[0044] As an implementable manner, as shown in Figure 3 , the first melt 21 extends towards the second melt 22 with a welding portion 211, and the first melt 21 is integrally formed, riveted, welded or bolted with the second melt 22 through the welding portion 211, so that the first melt 21 and the second melt 22 can be arranged in layers and spaced apart in a direction perpendicular to the second melt 22.
[0045] As an implementable manner, as shown in Figures 4 to 7 , the pre-break 11 and the conductor 23 are arranged in sequence on the movement path of the execution element 30, and the execution element 30 can continue to move towards the conductor 23 and break the conductor 23 after breaking the pre-break 11.
[0046] It should be noted that the circuit protection device 100 arranges the pre-break 11 and the conductor 23 in sequence on the displacement trajectory of the execution element 30 through the "execution element 30 motion path timing design", realizes the "pre-break 11 break first-conductor 23 break second" hierarchical breaking logic by the continuous motion of the execution element 30, combines the double-breakpoint arc extinguishing and mechanical linkage structure, and ensures the reliability of abnormal current transfer and circuit breaking.
[0047] Specifically, the pre-break 11 and the conductor 23 are arranged in sequence along the linear motion path (such as vertical downward) of the execution element 30, forming the layout feature of "spatial misalignment + distance difference", and ensuring that the execution element 30 can continuously act on the two breaking points. Under the condition of low-multiple abnormal current, the execution element 30 first cuts off the pre-break 11, the main loop 10 is disconnected, only the arc extinguishing branch 20 is conducted, and the low-multiple current flows into the arc extinguishing branch 20; the execution element 30 continues to move due to inertia (or continuous driving force), and the travel allowance ensures that the conductor 23 can be cut off, at this time the conduction path of the arc extinguishing branch 20 is cut off by the "conductor 23 breaking point", forming a double resistance of "double melt + conductor 23 breaking point".
[0048] The conductor 23 is a "temporary conductive channel" of the arc extinguishing branch 20, and its cutting time needs to be accurately matched with the heating and fusing process of the double melt. Under the condition of low-multiple, the first melt 21 has started to heat, and the cutting of the conductor 23 can avoid the explosion of the melt caused by the continuous current; under the condition of high-multiple, the cutting of the conductor 23 can cooperate with the fusing of the second melt 22 to form a "double-breakpoint arc extinguishing", further improving the system stability.
[0049] As an implementable way, as shown in the figure, Figure 5 The circuit protection device 100 further includes an excitation element 40, the conductor 23 is located on the motion path of the excitation element 40, and the execution element 30 can drive the excitation element 40 to act to move the excitation element 40 towards the conductor 23 to disconnect the conductor 23.
[0050] It should be noted that the circuit protection device 100 introduces the independent excitation element 40 as the power transmission intermediary between the execution element 30 and the conductor 23 through the "execution element 30-excitation element 40-conductor 23" two-stage transmission design, which not only ensures the independence of the pre-break 11 cutting, but also accurately controls the conductor 23 disconnection timing through the directional transmission of the excitation element 40, further optimizing the cooperative logic of abnormal current transfer and circuit breaking.
[0051] Specifically, the excitation element 40 can adopt a "lever type" or "slider type" mechanical structure 50 (such as a metal lever with a return spring or a plastic slider with a guide groove), which has the complete function of "force triggering-directional movement-resetting"; one end is provided with a "force receiving end" (cooperating with the execution element 30), the other end is provided with an "action end" (cooperating with the conductor 23), and the middle part is fixed on the inner shell through a rotating shaft or a guide structure, ensuring the unique movement track (only towards the conductor 23 direction).
[0052] The movement path of the execution element 30 can be divided into two sections: the first section path, only acting on the pre-break 11, the driving end of the execution element 30 first contacts the weak part of the pre-break 11, and cuts off the pre-break 11 through mechanical impact force, and in this stage, the excitation element 40 is not forced; the second section path, after the pre-break 11 is cut off, the execution element 30 continues to move, and its driving end contacts the force receiving end of the excitation element 40, pushing the excitation element 40 to rotate around the rotating shaft or slide along the guide groove, and transmitting power to the action end of the excitation element 40. The conductor 23 is located on the movement path of the excitation element 40, and when the excitation element 40 acts, its action end accurately hits the conductor 23 to cut off the conductor 23 through impact force.
[0053] As an implementable way, as shown in Figure 6 and Figure 7 The circuit protection device 100 further includes a mechanical structure 50 for locking the conductor 23 and the second fuse 22, and the execution element 30 can drive the mechanical structure 50 to act to release the locking of the conductor 23 and the second fuse 22, so as to realize the separation of the conductor 23 and the second fuse 22.
[0054] It should be noted that the circuit protection device 100 converts the conductor 23 and the second fuse 22 from "fixed connection" to "unlockable separation" state by adding a mechanical locking structure, and uses the unlocking action of the mechanical structure 50 driven by the execution element 30 to replace the "direct cutting" mode of the foregoing embodiment, so as to realize the non-destructive separation (resettable) of the conductor 23 and the second fuse 22, and at the same time ensure the reliability of abnormal current transfer and circuit cutting.
[0055] Specifically, the mechanical structure 50 can include two symmetrical clamping arms to clamp the conductor 23 on the second melting body 22 by pre-tightening force, ensuring reliable conduction under normal working conditions. Under the condition of low-multiple abnormal current, the execution element 30 first cuts off the pre-break 11, the main circuit 10 is disconnected, only the arc-extinguishing branch circuit 20 is connected, the low-multiple current flows into the arc-extinguishing branch circuit 20, and the mechanical structure 50 is not affected at this stage; after the pre-break 11 is cut off, the execution element 30 continues to move, the driving end of the execution element 30 contacts the clamping arm of the mechanical structure 50, pushes the clamping arm to rotate around the rotation shaft, and switches from the "clamping state" to the "open state", thereby releasing the locking of the conductor 23 and the second melting body 22, the conductor 23 and the second melting body 22 are disconnected under the action of gravity, the arc-extinguishing branch circuit 20 is disconnected, the circuit is completely powered off, and the arc-extinguishing purpose is achieved.
[0056] The above only describes optional embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
[0057] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.
Claims
1. A circuit protection device, characterized in that, The circuit includes a main circuit (10) with a pre-break (11) and an arc-extinguishing branch (20) connected to both ends of the pre-break (11) and in parallel with the main circuit (10). At least a first melt (21) and a second melt (22) are connected in series on the arc-extinguishing branch (20). When an abnormal current passes through the main circuit (10), the pre-break (11) breaks first, and the abnormal current flows through the arc-extinguishing branch (20). The first melt (21) melts before the second melt (22).
2. The circuit protection device according to claim 1, characterized in that, The first melt (21) and the second melt (22) are made of the same material, and the resistance of the second melt (22) is higher than that of the first melt (21); or, the first melt (21) and the second melt (22) are made of different materials, and the melting point of the second melt (22) is higher than that of the first melt (21).
3. The circuit protection device according to claim 1, characterized in that, It also includes an actuator (30), and at least two ends of the first melt (21) are connected in parallel with conductors (23). The internal resistance of the conductors (23) is less than the internal resistance of the main circuit (10). The actuator (30) can first disconnect the pre-break (11). When only the arc-extinguishing branch (20) is connected, the conductors (23) can be disconnected by the actuator (30).
4. The circuit protection device according to claim 3, characterized in that, The first melt (21), the second melt (22) and the conductor (23) are distributed in the same layer. The first melt (21) and the conductor (23) are spaced apart on one side of the second melt (22). The first melt (21) and the conductor (23) are respectively connected to the second melt (22).
5. The circuit protection device according to claim 3, characterized in that, The first melt (21) and the second melt (22) are stacked and spaced apart, the conductor (23) and the second melt (22) are distributed in the same layer, and the first melt (21) and the conductor (23) are respectively connected to the second melt (22).
6. The circuit protection device according to claim 5, characterized in that, The first melt (21) extends toward the second melt (22) with a welding part (211), and the first melt (21) is integrally formed, riveted, welded or bolted to the second melt (22) through the welding part (211).
7. The circuit protection device according to any one of claims 3 to 6, characterized in that, The conductor (23) and the second melt (22) are fixed by integral molding, riveting, welding or bolting.
8. The circuit protection device according to claim 3, characterized in that, The pre-break (11) and the conductor (23) are sequentially arranged on the movement path of the actuator (30). After the actuator (30) disconnects the pre-break (11), it can continue to move toward the conductor (23) and disconnect the conductor (23).
9. The circuit protection device according to claim 3, characterized in that, It also includes an excitation element (40), the conductor (23) is located on the movement path of the excitation element (40), and the actuation element (30) can drive the excitation element (40) to move toward the conductor (23) to disconnect the conductor (23).
10. The circuit protection device according to claim 3, characterized in that, It also includes a mechanical structure (50) for locking the conductor (23) and the second melt (22), and the actuator (30) is capable of driving the mechanical structure (50) to release the mechanical structure (50) from locking the conductor (23) and the second melt (22) to achieve separation of the conductor (23) and the second melt (22).