Fuse and battery pack

Abstract

This invention relates to the field of battery technology and discloses a fuse and a battery pack, which includes an insulating shell, a first terminal, a second terminal, a fusible element, a conductive moving part, a controller, and a driving unit. The fusible element includes a substrate and a narrow section. The controller's detection module detects the current signal of the circuit and sends it to a judgment module. When the current in the circuit is greater than the rated current, the driving unit drives the conductive moving part to move to make electrical connection with the substrate. When the current in the circuit is less than or equal to the rated current, the current directly flows from the first terminal through the conductive moving part to the second terminal without passing through the fusible element, preventing the problem of excessive temperature caused by the temperature rise of the fusible element under the rated current and the aggravated temperature rise of the fusible element under unstable current. When the circuit current is greater than the rated current, the driving unit controls the conductive moving part to move to the fusible element, and the current passes through the fusible element. The narrow section of the fusible element with multiple hollow holes allows the fusible element to melt normally and quickly, thereby preventing the circuit current from overloading.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a fuse and a battery pack. Background Technology

[0002] Currently, fuses installed in the high-voltage circuit of power batteries commonly suffer from excessive temperature rise during fast charging. Fuses, connected in series in the high-voltage circuit, protect the electrical system by melting their own fuse element. When the fuse element melts, heat accumulates due to the circuit current, its own resistance, and the current-carrying time, converting into a temperature rise in the fuse element. Once the temperature exceeds the melting point, the fuse melts. When the circuit current is less than the rated current, the fuse acts like a conductor and does not melt; when the circuit current exceeds the allowable rated current, it must melt to protect the circuit. The current is high during fast charging, and the fuse experiences significant temperature rise after prolonged operation in the circuit, especially under unstable currents such as inrush currents. Even if the fuse element does not melt, it will suffer varying degrees of wear, reducing its lifespan and potentially rendering it unusable, thus posing a safety hazard to the battery pack. Summary of the Invention

[0003] The main objective of this invention is to provide a fuse that solves the technical problem that fuses cannot be used safely during their lifespan.

[0004] To achieve the above objectives, the present invention provides a fuse comprising an insulating housing having an internal receiving cavity;

[0005] The first terminal is connected to the insulating shell, with one end extending into the receiving cavity and the other end used for electrical connection with the battery pack circuit.

[0006] The second terminal is connected to the insulating shell and is used for electrical connection with the battery pack circuit. Current is input from the first terminal and output from the second terminal.

[0007] The melt includes a substrate and a narrow portion formed on the substrate, the narrow portion having a plurality of perforations, the substrate being located within the receiving cavity and electrically connected to the first terminal;

[0008] A conductive movable element is located in the receiving cavity and has one end electrically connected to the first terminal or the substrate and is movable on the first terminal or the substrate, and the other end is electrically connected to the second terminal to form a passage;

[0009] The controller includes a detection module and a judgment module. The detection module is connected to the path, and the detection module and the judgment module are electrically connected. The detection module is used to detect the current signal of the path and output it to the judgment module.

[0010] A driving component, which is electrically connected to the judgment module, and the driving component is connected to the conductive moving component;

[0011] When the judgment module determines that the current in the path is greater than the rated current, the driving member drives the conductive moving member to move to a position that is electrically connected to the substrate and the current flows through the narrow section.

[0012] In some embodiments of this application, the narrow diameter portion includes a first narrow diameter portion and a second narrow diameter portion, the first narrow diameter portion is connected to the first terminal, the second narrow diameter portion is disposed between the first narrow diameter portion and the second terminal, and the second narrow diameter portion is connected to the first narrow diameter portion;

[0013] The rated current includes a first rated current and a second rated current, wherein the second rated current is greater than the first rated current.

[0014] When the current in the passage is greater than the first rated current, the driving member drives the conductive moving member to move to the first narrow section, the conductive moving member is connected to the first narrow section, and the current flows through the position of the first narrow section;

[0015] or,

[0016] When the current in the passage is greater than the second rated current, the driving member drives the conductive moving member to move to the second narrow section. The conductive moving member is connected to the second narrow section, and the current flows through the positions of the first narrow section and the second narrow section.

[0017] In some embodiments of this application, the second rated current is two times or more than two times the first rated current.

[0018] In some embodiments of this application, the insulating shell has a first end and a second end disposed opposite to each other along the length direction of the substrate, the first terminal extends into the first end of the insulating shell, the second terminal extends into the second end of the insulating shell, and the substrate is electrically connected to the end of the first terminal facing the second terminal.

[0019] In some embodiments of this application, the fuse further includes an insulating limiting member disposed in the receiving cavity and located in the moving direction of the conductive moving member, for preventing the conductive moving member from detaching from the end of the substrate.

[0020] In some embodiments of this application, the insulating limiting member is disposed at the end of the substrate away from the first terminal.

[0021] In some embodiments of this application, the second terminal includes a second end body and a second clip;

[0022] One end of the second end body extends into the insulating shell, and the second clip is disposed at one end of the second end body located in the receiving cavity, and the second clip extends along the width direction of the substrate for connecting the conductive moving part.

[0023] In some embodiments of this application, the conductive moving member includes a first rod and a first clip;

[0024] The first rod extends along the length of the substrate, and one end of the rod facing the second terminal is connected to the second clip. The first rod can move relative to the second clip along the length of the substrate.

[0025] The first clamp is connected to the end of the first rod facing the first terminal and is connected to the first terminal or the substrate. The driving member is connected to the first rod and pushes the first clamp to move relative to the first terminal or the substrate along the length direction of the substrate.

[0026] In some embodiments of this application, the first clip is provided with a collar, which is sleeved on the substrate.

[0027] In some embodiments of this application, the substrate is columnar, and the perforated holes are multiple and arranged along the circumference of the substrate.

[0028] In some embodiments of this application, the fuse further includes an arc-extinguishing medium that fills the receiving cavity.

[0029] A battery pack includes a housing, a battery pack, a BDU controller, and the aforementioned fuse. The housing is provided with a receiving chamber for accommodating the battery pack, the BDU controller, and the fuse. The battery pack is electrically connected to a first terminal, and the BDU controller is electrically connected to a second terminal.

[0030] The present invention provides a fuse and battery pack. Because a fusible element is arranged along the length of the first terminal, electrically connecting the first terminal to the fusible element, when the current is less than or equal to the rated current, the current directly flows from the first terminal through a conductive moving part to the second terminal, without needing to pass through the fusible element. This prevents overheating caused by temperature rise of the fusible element under rated current and excessive temperature rise under unstable current. When the circuit current exceeds the rated current, a driving component controls the conductive moving part to move to the fusible element, allowing the current to pass through it. The fusible element has a narrow section with multiple perforated holes, enabling it to melt normally and quickly, thereby preventing circuit current overload, ensuring safe operation of the fuse during its service life, and reducing the risk of abnormal battery pack operation. Attached Figure Description

[0031] Figure 1This is a schematic diagram of the internal structure of the fuse of the present invention. Figure 1 ;

[0032] Figure 2 This is a schematic diagram of the internal structure of the fuse of the present invention. Figure 2 ;

[0033] Figure 3 This is a schematic diagram of the internal structure of the fuse of the present invention. Figure 3 ;

[0034] Figure 4 This is a schematic diagram of the melt structure;

[0035] Figure 5 This is a schematic diagram of the controller;

[0036] Among them, the insulating shell 1; the receiving cavity 11; the first end 101; the second end 102; the first terminal 2; the second terminal 3; the second end body 31; the second clamping piece 32; the melt 4; the substrate 41; the narrow diameter portion 42; the hollow hole 421; the first narrow diameter portion 422; the second narrow diameter portion 423; the conductive moving part 5; the first rod body 51; the first clamping piece (52); the collar 521; the controller 6; the detection module 61; the judgment module 62; the driving part 7; and the insulating limiting part 8.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and the accompanying drawings. Detailed Implementation

[0038] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] It should be noted that the terms "first" and "second" are used for descriptive purposes only to distinguish technical features of the same type, and should not be construed as indicating or implying the relative importance, order, or number of these technical features. That is, a "first" technical feature can be referred to as a "second" technical feature, and a "second" technical feature can also be referred to as a "first" technical feature. Furthermore, technical features specified as "first" or "second" may explicitly or implicitly include one or more of that technical feature. In addition, unless otherwise stated, "multiple" means two or more.

[0040] It should be emphasized that, in the description of this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0041] like Figure 1 and 2 As shown, the present invention provides a fuse, which includes an insulating shell 1, a first terminal 2, a second terminal 3, a fusible element 4, a conductive moving part 5, a controller 6, and a driving part 7. The controller 6 controls the conductive moving part 5 to move on the fusible element 4 according to the magnitude of the current, so that the fusible element 4 can melt immediately when the current is too large.

[0042] like Figure 1 As shown, the insulating shell 1 forms a cavity 11 inside, which can accommodate various components. The insulating shell 1 protects the components within the cavity 11. The first terminal 2 is connected to the insulating shell 1 and is fixed relative to it. The first terminal 2 is elongated, with one end extending into the cavity 11 and having a certain extension length, while the other end protrudes outside the insulating shell 1. The first terminal 2 located outside the insulating shell 1 is used for electrical connection with the battery pack circuitry. The first terminal 2 is made of a metal sheet, possessing good conductivity and elasticity. The second terminal 3 is connected to the insulating shell 1 and is fixed relative to it. The second terminal 3 is used for electrical connection with the battery pack circuitry. In actual use, current is input from the first terminal 2 and output from the second terminal 3. Figure 1-4 As shown, the melt 4 includes a substrate 41 and a narrow diameter portion 42 formed on the substrate 41. The narrow diameter portion 42 has multiple perforated holes 421, which can be one or a combination of round holes, polygonal holes, or both. The substrate 41 with the narrow diameter portion 42 has a smaller effective current-carrying area and higher resistance compared to the first terminal 2, making it easier to melt when a large current is carried. The substrate 41 is located in the receiving cavity 11 and is electrically connected to the first terminal 2. In this embodiment, the substrate 41 is a metal sheet, and the substrate 41 is integrally formed with the first terminal 2; in other embodiments, the substrate 41 is in contact with the first terminal 2 for electrical connection, or one end of the substrate 41 is welded to the first terminal 2 for electrical connection.

[0043] like Figure 1-3As shown, the conductive movable element 5 is located within the receiving cavity 11. The conductive movable element 5 is made of conductive metal and can move within the receiving cavity 11. One end of the conductive movable element 5 is conductively connected to the first terminal 2 or the substrate 41, and the other end is conductively connected to the second terminal 3 to form a circuit. When current flows through the first terminal 2, the current can travel from the first terminal 2 through the conductive movable element 5 to the second terminal 3, or it can travel from the first terminal 2 through the substrate 41 and the conductive movable element 5 to the second terminal 3. That is, the first terminal 2 and the second terminal 3 are spaced apart and need to be electrically connected by the conductive movable element 5.

[0044] like Figure 1-5 As shown, the controller 6 includes a detection module 61 and a judgment module 62. The detection module 61 is located in the receiving cavity 11 and connected to the passage. The detection module 61 and the judgment module 62 are electrically connected. The detection module 61 is used to detect the current signal of the passage and output it to the judgment module 62. The detection module 61 can be a current sensor or an ammeter, mainly used to detect the current magnitude of the passage. The driving component 7 is electrically connected to the judgment module 62. The judgment module 62 is a processor that can control the operation of the driving component 7 according to the current magnitude detected by the detection module 61. The driving component 7 is located in the receiving cavity 11 and connected to the conductive moving component 5. The driving component 7 can be a linear motor, a cylinder, or a lead screw linear slide module. The driving component 7 can control the translation of the conductive moving component 5, so that the conductive moving component 5 slides between the first terminal 2 and the substrate 41.

[0045] It should be noted that the detection module 61 can also be located outside the receiving cavity 11 and connected to the passage. For example, it can be connected to the passage via a wire.

[0046] When the judgment module 62 determines that the current in the circuit is greater than the rated current, the driving component 7 drives the conductive moving component 5 to move to the substrate 41. At this time, the conductive moving component 5 is in direct contact with the substrate 41 and electrically connected. The current flows through the first terminal 2, the narrow section 42, the conductive moving component 5 and the second terminal 3. Since the resistance of the narrow section 42 is relatively greater than that of the first terminal 2, the temperature of the narrow section 42 rises rapidly and melts. After the narrow section 42 melts, the conductive medium between the first terminal 2 and the conductive moving component 5 is lost, the circuit is broken, and the current cannot flow between the first terminal 2 and the second terminal 3, thereby realizing the function of the fuse protection circuit. By setting the fuse 4 along the length of the first terminal 2, the first terminal 2 is electrically connected to the fuse 4. When the circuit current is less than or equal to the rated current, the current directly flows from the first terminal 2 through the conductive moving part 5 to the second terminal 3. The current does not need to pass through the fuse 4, which prevents the fuse 4 from overheating under the rated current and under unstable current. When the circuit current is greater than the rated current, the driving part 7 controls the conductive moving part 5 to move to the fuse 4, and the current passes through the fuse 4. The fuse 4 is provided with a narrow section 42 so that it can melt normally and quickly, thereby preventing the circuit current from overload and ensuring the safe operation of the fuse during its service life.

[0047] like Figure 1-3 As shown, the insulating shell 1 has a first end 101 and a second end 102 along the length of the substrate 41. The first terminal 2 extends into the first end 101 of the insulating shell 1, and the substrate 41 is electrically connected to the end of the first terminal 2 facing the second terminal 3. In this embodiment, the second terminal 3 is elongated, extending into the second end 102 of the insulating shell 1 and located within the receiving cavity 11. The other end of the second terminal 3 is exposed outside the insulating shell 1. The insulating shell 1 can protect the portion of the second terminal 3 located within the receiving cavity 11. The second terminal 3 is made of a metal sheet and has good conductivity and elasticity. In other embodiments, the second terminal 3 can be disposed outside the insulating shell 1, for example, fixed to the outer surface of the insulating shell 1, and connected by electrical connection elements such as wires and conductive moving parts 5. The second terminal 3 can be block-shaped or sheet-shaped. Disposing the second terminal 3 outside the insulating shell 1 facilitates the assembly of the second terminal 3 with the insulating shell 1 during the production of the fuse.

[0048] like Figure 1-3As shown, the second terminal 3 includes a second end body 31 and a second clip 32. One end of the second end body 31 extends into the insulating housing 1. The second clip is located at one end of the second end body 31 in the receiving cavity 11, and the second clip 32 extends along the width direction of the substrate 41 for connecting the conductive moving member 5. In this embodiment, the second clip 32 is clamped on the conductive moving member 5 to ensure that the second clip 32 can always maintain an electrical connection with the conductive moving member 5 and will not detach from the conductive moving member 5. In other embodiments, the second clip 32 can directly abut against the conductive moving member 5. When the conductive moving member 5 moves, sliding friction occurs between the second clip 32 and the conductive moving member 5. The fuse is produced by using the method of the second clip 32 abutting against the conductive moving member 5, which results in lower production costs and makes it easier for the conductive moving member 5 to slide on the second clip 32.

[0049] like Figure 1-3 As shown, the conductive moving member 5 includes a first rod 51 and a first clamping piece 52. The first rod 51 extends along the length direction of the substrate 41, and the end of the first rod 51 facing the second terminal 3 is connected to the second clamping piece 32. The first rod 51 is movable relative to the second clamping piece 32 along the length direction of the substrate 41. The first clamping piece 52 is connected to the end of the first rod 51 facing the first terminal 2 and connects to the first terminal 2 or the substrate 41. The driving member 7 is connected to the first rod 51, and the driving member 7 pushes the first rod 51 to move relative to the first terminal 2 or the substrate 41 along the length direction of the substrate 41. The first clamping piece 52 moves with the first rod 51.

[0050] like Figure 2-3 As shown, in this embodiment, the first clamping piece 52 is provided with a collar 521, which is sleeved on the substrate 41. The collar 521 slides and rubs against the substrate 41. When the driving member 7 drives the conductive moving member 5 to move, the collar 521 slides and electrically connects on the first terminal 2 and the substrate 41. Current can flow from the first terminal 2 to the collar 521, then to the first rod 51, and then to the second terminal 3. In other embodiments, the first clamping piece 52 can be a spring clip. The first clamping piece 52 abuts against the substrate 41 or the first terminal 2. The fuse is produced by using the method of the first clamping piece 52 abutting against the first terminal 2, which reduces the production cost and makes it easier for the first clamping piece 52 to slide on the first terminal 2 and the substrate 41.

[0051] The fuse also includes an arc-extinguishing medium, which is filled in the receiving cavity 11. When the fuse is working normally and the circuit carries the rated current, the arc-extinguishing medium can prevent the generation of an electric arc between the conductive moving part 5 and the substrate 41, and prevent the substrate 41 from melting due to the electric arc, thereby affecting the normal operation of the fuse.

[0052] Example 1

[0053] like Figure 1-4 As shown, the narrow diameter portion 42 includes a first narrow diameter portion 422 and a second narrow diameter portion 423. The first narrow diameter portion 422 is connected to the first terminal 2, and the second narrow diameter portion 423 is disposed between the first narrow diameter portion 422 and the second terminal 3. The second narrow diameter portion 423 is connected to the first narrow diameter portion 422. The first narrow diameter portion 422 and the second narrow diameter portion 423 are integrally formed. In this embodiment, the porosity of the hollow hole 421 on the first narrow diameter portion 422 is the same as the porosity of the hollow hole 421 on the second narrow diameter portion 423. In other embodiments, the porosity of the hollow hole 421 on the second narrow diameter portion 423 can be greater than the porosity of the hollow hole 421 on the first narrow diameter portion 422.

[0054] The rated current includes a first rated current and a second rated current, where the second rated current is greater than the first rated current. When the current in the circuit is greater than the first rated current but less than the second rated current, the driving member 7 drives the conductive moving member 5 to move to the first narrow diameter portion 422. The conductive moving member 5 is connected to the first narrow diameter portion 422, and the current flows through the first terminal 2, the first narrow diameter portion 422, the conductive moving member 5, and the second terminal 3. When the current in the circuit is greater than the second rated current, the driving member 7 drives the conductive moving member 5 to move to the second narrow diameter portion 423, where the conductive moving member 5 is connected to the second narrow diameter portion 423. The current flows through the first terminal 2, the first narrow diameter portion 422, the second narrow diameter portion 423, the conductive moving member 5, and the second terminal 3. At this time, because the current flows a greater distance through the substrate 41 with the perforated hole 421, the substrate 41 heats up faster and melts more quickly. When the current in the circuit is too large, the connection between the first terminal 2 and the second terminal 3 can be disconnected more promptly, thus better protecting the circuit. Specifically, the magnitude of the second rated current is twice or more than the magnitude of the first rated current. When the current in the circuit is greater than the second rated current, the melting speed of the substrate is more than twice that when the current in the circuit is less than the second rated current, ensuring that the substrate can melt quickly when the current in the circuit is greater than the second rated current, thereby protecting the entire circuit.

[0055] Alternatively, the second rated current is the minimum breaking current of the fuse, that is, the minimum breaking current is twice or more than the first rated current.

[0056] Optionally, the first narrow diameter portion 422 may be provided with at least one row of perforated holes 421. When it is provided with two or more rows, they can be arranged at intervals along the length direction of the substrate 41. The second narrow diameter portion 423 may be provided with at least one row of perforated holes 421. When it is provided with two or more rows, they can be arranged at intervals along the length direction of the substrate 41. Embodiment 2

[0057] like Figure 2-3 As shown, the fuse includes an insulating limiting member 8, which is disposed within the receiving cavity 11. The insulating limiting member 8 can be made of insulating materials such as plastic, ceramic, rubber, or silicone. The insulating limiting member 8 is located in the moving direction of the conductive moving member 5 and is used to prevent the conductive moving member 5 from moving towards the second terminal 3 and detaching from the substrate 41. When the current in the circuit is much greater than the rated current, the driving member 7 will drive the conductive moving member 5 to move towards the second terminal 3 until the conductive moving member 5 contacts the insulating limiting member 8. The insulating limiting member 8 blocks the conductive moving member 5, preventing the conductive moving member 5 from moving excessively and colliding with other components in the receiving cavity 11.

[0058] The insulating limiting member 8 is disposed at the end of the substrate 41 away from the first terminal 2. The insulating limiting member 8 can be directly bonded to the end of the first terminal 2, or it can be fixed to the end of the first terminal 2 by welding, or it can be fixed to the end of the first terminal 2 by snap-fit, or it can be screwed to the end of the first terminal 2. In addition, the insulating limiting member 8 may not be in contact with the end of the first terminal 2. The insulating limiting member 8 can be fixed to the receiving cavity 11, as long as it is located at the end of the first terminal 2.

[0059] Example 3

[0060] like Figure 2 As shown, the substrate 41 is columnar, and the perforated holes 421 are multiple and arranged circumferentially along the substrate 41. The columnar substrate 41 has stronger structural strength and a longer lifespan when the fuse is working normally. In addition, if the first clip 52 is provided with a collar 521, the collar 521 can slide more easily on the substrate 41.

[0061] A battery pack includes a housing, a battery pack, a BDU controller, and a fuse. The housing has a cavity for accommodating the battery pack, the BDU controller, and the fuse. The battery pack is electrically connected to a first terminal 2, and the BDU controller is electrically connected to a second terminal 3. When the battery pack discharges, the battery pack can supply power to the BDU controller, and the battery pack outputs current. The current can flow from the battery pack through the first terminal 2, the conductive moving part 5, the second terminal 3, and then to the BDU controller. When the current exceeds the rated current, the driving part 7 controls the conductive moving part 5 to move to the fuse 4, and the fuse 4 quickly melts, disconnecting the first terminal 2 and the conductive moving part 5, thereby protecting the battery pack and the BDU controller.

[0062] In summary, the fuse and battery pack proposed in this invention have at least the following advantages compared with the prior art:

[0063] First, by setting a fuse 4 along the length of the first terminal 2, the first terminal 2 is electrically connected to the fuse 4. When the circuit current is less than or equal to the rated current, the current does not need to pass through the fuse 4, thus preventing the overheating problem caused by the temperature rise of the fuse 4 under the rated current and the aggravated temperature rise of the fuse 4 under unstable current. When the circuit current is greater than the rated current, the current passes through the fuse 4, and the fuse 4 can melt normally, thereby preventing the circuit current from overload and ensuring the safe operation of the fuse during its service life.

[0064] Second, the narrow section 42 includes a first narrow section 422 and a second narrow section 423. When the current in the circuit is greater than the second rated current, the driving member 7 controls the conductive moving member 5 to move to the second narrow section 423, the temperature of the molten element 4 rises faster, the melting speed is faster, and the fuse can protect other components more promptly.

[0065] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A fuse, characterized in that, include: An insulating outer shell (1) has an internal cavity (11) formed therein. The first terminal (2) is connected to the insulating shell (1) and one end of it extends into the receiving cavity (11), while the other end is used for electrical connection with the battery pack circuit. The second terminal (3) is connected to the insulating shell (1) and is used for electrical connection with the battery pack circuit. Current is input from the first terminal (2) and output from the second terminal (3). The melt (4) includes a substrate (41) and a narrow section (42) formed on the substrate (41), the narrow section (42) having a plurality of hollow holes (421), the substrate (41) being located in the receiving cavity (11) and electrically connected to the first terminal (2); A conductive movable element (5) is located in the receiving cavity (11) and one end is electrically connected to the first terminal (2) or the substrate (41) and is movable on the first terminal (2) or the substrate (41), and the other end is electrically connected to the second terminal (3) to form a passage; The controller (6) includes a detection module (61) and a judgment module (62). The detection module (61) is connected to the path, and the detection module (61) and the judgment module (62) are electrically connected. The detection module (61) is used to detect the current signal of the path and send it to the judgment module (62). The driving component (7) is electrically connected to the judgment module (62), and the driving component (7) is connected to the conductive moving component (5); When the judgment module (62) determines that the current in the passage is greater than the rated current, the driving member (7) drives the conductive moving member (5) to move to a position that is electrically connected to the substrate (41) and the current flows through the narrow section (42); when the judgment module (62) determines that the current in the passage is less than or equal to the rated current, the current directly flows from the first terminal (2) through the conductive moving member (5) to the second terminal (3), and the current does not need to pass through the melt (4); The fuse also includes an insulating limiting member (8), which is disposed in the receiving cavity (11). The insulating limiting member (8) is located in the moving direction of the conductive moving member (5) and is used to prevent the conductive moving member (5) from disengaging from the end of the substrate (41).

2. The fuse of claim 1, wherein The narrow section (42) includes a first narrow section (422) and a second narrow section (423). The first narrow section (422) is connected to the first terminal (2). The second narrow section (423) is disposed between the first narrow section (422) and the second terminal (3). The second narrow section (423) is connected to the first narrow section (422). The rated current includes a first rated current and a second rated current, wherein the second rated current is greater than the first rated current. When the current in the passage is greater than the first rated current, the driving member (7) drives the conductive moving member (5) to move to the first narrow section (422), the conductive moving member (5) is connected to the first narrow section (422), and the current flows through the position of the first narrow section (422); or, When the current in the passage is greater than the second rated current, the driving member (7) drives the conductive moving member (5) to move to the second narrow section (423). The conductive moving member (5) is connected to the second narrow section (423), and the current flows through the positions of the first narrow section (422) and the second narrow section (423).

3. The fuse of claim 2, wherein The second rated current is two times or more than the first rated current.

4. The fuse of claim 1, wherein The insulating shell (1) has a first end (101) and a second end (102) disposed opposite to each other along the length direction of the substrate (41). The first terminal (2) extends into the first end (101) of the insulating shell (1), and the second terminal (3) extends into the second end (102) of the insulating shell (1). The substrate (41) is electrically connected to the end of the first terminal (2) facing the second terminal (3).

5. The fuse of claim 1, wherein The insulating limiting member (8) is located at the end of the substrate (41) away from the first terminal (2).

6. The fuse of claim 1, wherein: The second terminal (3) includes a second end body (31) and a second clip (32); One end of the second end body (31) extends into the insulating shell (1), and the second clip (32) is located at one end of the second end body (31) in the receiving cavity (11), and the second clip (32) extends along the width direction of the substrate (41) for connecting the conductive moving part (5).

7. The fuse of claim 6, wherein The conductive moving part (5) includes a first rod (51) and a first clip (52); The first rod (51) extends along the length direction of the substrate (41), and its end facing the second terminal (3) is connected to the second clip (32). The first rod (51) can move relative to the second clip (32) along the length direction of the substrate (41). The first clip (52) is connected to the end of the first rod (51) facing the first terminal (2) and connected to the first terminal (2) or the substrate (41). The driving member (7) is connected to the first rod (51) and the driving member (7) pushes the first clip (52) to move relative to the first terminal (2) or the substrate (41) along the length direction of the substrate (41).

8. The fuse of claim 7, wherein, The first clip (52) is provided with a collar (521), which is sleeved on the substrate (41).

9. The fuse according to claim 8, characterized in that, The substrate (41) is columnar, and the perforated holes (421) are multiple and arranged circumferentially along the substrate (41).

10. The fuse according to any one of claims 1-9, characterized in that, Also includes: An arc-extinguishing medium is filled in the receiving cavity (11).

11. A battery pack, characterized in that: The device includes a housing, a battery pack, a BDU controller, and a fuse as described in any one of claims 1-10. The housing is provided with a housing chamber for accommodating the battery pack, the BDU controller, and the fuse. The battery pack is electrically connected to the first terminal (2), and the BDU controller is electrically connected to the second terminal (3).

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