Melt, fuse and electrical equipment

Abstract

The invention discloses a melt, a fuse and electrical equipment, in the melt of the fuse, the overcurrent area of a fusing region is smaller than that of a non-fusing region, the fusing region is made of a first material, the non-fusing region is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material. The impact of the mechanical property of the material is considered, and the regional design of hardness and strength is adopted, so that the thermal stress is greatly relieved and released, the defect of weak structure of a fusing region is overcome, the problem of life damage under large pulse current is solved, and the anti-fatigue performance of the fuse is enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of circuit protection devices, and more specifically, to a fuse, a fuse and an electrical device. Background Art

[0002] A fuse is a device that implements a protective function based on the thermal effect of current. For example, a fuse can be an important component of the battery pack distribution system, and its life is related to the safety and reliability of the entire battery pack. In order to ensure the airtightness level of the battery pack and other requirements, the fuse or distribution box is often located inside the battery pack, so the failure of the fuse will face high repair costs for the entire pack. However, the discharge threshold of the battery pack is getting higher and higher, causing the fuse to withstand higher peak currents. The high-temperature and closed environment further reduces the pulse resistance of the fuse. Once the fuse life reaches its limit, it will cause the protection function to fail, the circuit to become unstable, and cause serious safety hazards. In related technologies, the fuse melt has defects such as stress concentration areas in the melting area and easy attenuation of life due to defects in material and structural design. Summary of the Invention

[0003] The embodiments of the present application provide a melt, a fuse, and an electrical device, aiming to enhance the performance of the melt and extend the service life of the melt, the fuse using the melt, and the electrical device.

[0004] The technical solution of this application is as follows.

[0005] A fuse element for a fuse, comprising:

[0006] Two non-fuse regions for forming a current flow path; and

[0007] a fusing area connected between the two non-fusing areas and configured to fuse when the current exceeds a predetermined threshold;

[0008] The overflow area of ​​the melting zone is smaller than that of the non-melting zone. The melting zone is made of a first material and the non-melting zone is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material.

[0009] Optionally, the first material includes at least one of silver, copper, and silver-copper alloy, and the second material is aluminum.

[0010] Optionally, the melting area and the non-melting area are connected by a melt composite process.

[0011] Optionally, the melt bonding process includes: rolling bonding, diffusion bonding, and brazing.

[0012] Optionally, the melt is in sheet form and includes a plurality of non-melting areas and a plurality of melting areas that are alternately arranged and connected in series, and the melting areas are formed with openings.

[0013] Optionally, the non-melting areas of the melt at both ends of the length direction constitute connecting ends, and the length of the melt is L and satisfies:

[0014] L=(N-1)d+2h=(u / W-1)d+2h

[0015] Among them, N is the number of the fuse zones; h is the length of the connection end; d is the span between two adjacent fuse zones; u is the predetermined voltage value that the fuse can withstand; W is the predetermined voltage value that each fuse zone can withstand; the units of L, d, and h are mm, and the units of u and W are V.

[0016] Optionally, the value range of W is 150V-200V.

[0017] Optionally, the span d ranges from 10 mm to 20 mm.

[0018] Optionally, along the length direction of the melt, the width of the melting zone is a, the width of the non-melting zone is b, and they satisfy 10 mm < a + b < 20 mm.

[0019] Optionally, the aperture of the opening formed in the fusing zone is Φ, in mm, and satisfies a>2Φ.

[0020] Optionally, the non-melting area between the melting areas is bent at a predetermined angle.

[0021] Optionally, the bending angle is θ, and the value range of θ is 30°≤θ<180°.

[0022] Optionally, the angle θ is 90°.

[0023] The present application also discloses a fuse, comprising a first connecting terminal, a second connecting terminal and a fuse element, wherein two ends of the fuse element are electrically connected to the first connecting terminal and the second connecting terminal respectively; the fuse element is any of the aforementioned fuse elements.

[0024] The present application also discloses an electrical device, comprising the aforementioned fuse or the aforementioned fuse.

[0025] In the fuse element used in the present application, the flow area of ​​the melting zone is smaller than that of the non-melting zone, the melting zone is made of a first material, and the non-melting zone is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material. Taking into account the influence of the mechanical properties of the material, a regionalized design of hardness and strength is adopted, which greatly alleviates and releases thermal stress, compensates for the defect of weak structure of the melting zone, solves the problem of life damage under large pulse current, and enhances the fatigue resistance of the fuse.

[0026] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 It is a schematic structural diagram of a fuse in certain embodiments of the present application.

[0029] Figure 2 It is a schematic structural diagram of the melt of certain embodiments of the present application.

[0030] Figure 3 It is a schematic structural diagram of the melt in another embodiment of the present application.

[0031] Figure 4 yes Figure 3 Side view of the melt shown.

[0032] Figure 5 It is a schematic structural diagram of the melt in another embodiment of the present application.

[0033] Figure 6 Yes Figure 5 Side view of the melt shown.

[0034] Figure 7 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 160°.

[0035] Figure 8 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 150°.

[0036] Figure 9 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 120°.

[0037] Figure 10 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 90°.

[0038] Figure 11 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 60°.

[0039] Figure 12 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 30°.

[0040] Figure 13 for Figures 7 to 12 Schematic diagram of test conditions in an embodiment of the present invention.

[0041] Description of main component symbols:

[0042] 100. Fuse;

[0043] 10. Housing;

[0044] 21. First connecting terminal; 22. Second connecting terminal

[0045] 30. Melt; 31. Melting zone; 32. Non-melting zone; 310. Opening;

[0046] 40. Filling parts. DETAILED DESCRIPTION

[0047] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and should not be understood as limiting the embodiments of the present application.

[0048] In the description of the present application, it should be understood that the terms "thickness", "upper", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0049] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. In an example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements.

[0050] In the embodiments of the present application, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0051] See also Figure 1 The fuse 100 provided in the embodiment of the present application includes a housing 10, a first connecting terminal 21, a second connecting terminal 22, a fuse 30 and a filler 40, and may also include fixing screws.

[0052] Specifically, the fuse element 30 of the fuse 100 is located within the cavity of the housing 10, with its two ends electrically connected to the first connecting terminal 21 and the second connecting terminal 22, respectively. The filler 40 densely fills the cavity of the housing 10, surrounding the fuse element 30. Fixing screws securely connect the first and second connecting terminals 21, 22 to the ends of the housing 10. The fuse 100 is connected to the circuit via the first and second connecting terminals 21, 22, so that it melts when the circuit current exceeds a predetermined threshold, thereby achieving a protective function. It will be understood that, in specific implementations, the specific form of the fuse 100 is not limited thereto, as long as the fuse element 30 disclosed in this application is employed.

[0053] Ginseng Figures 2 to 6 As shown, the fuse element 30 for the fuse 100 may include two non-melting areas 32 and a melting area 31. In a specific implementation, the number of the non-melting areas 32 may be multiple, and the number of the melting areas 31 may be one or more, without specific limitation.

[0054] The two non-melting areas 32 are used to form a current flow path. The melting area 31 is connected between the two non-melting areas 32 and is used to melt when the current exceeds a predetermined threshold. For example, when the fuse 30 includes two non-melting areas 32 and one melting area 31, the two non-melting areas 32 form a current connection terminal that can be connected to the current loop, and the melting area 31 is connected between the two non-melting areas 32 to form a current flow path together. When the fuse 30 includes more than two non-melting areas 32 and multiple melting areas 31, two of the non-melting areas 32 can form a current connection terminal that can be connected to the current loop, and the melting area 31 is connected between the two non-melting areas 32 to form a current flow path together.

[0055] The flow area of ​​the melting zone 31 is smaller than that of the non-melting zone 32. The melting zone 31 is made of a first material, and the non-melting zone 32 is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material.

[0056] In the melt 30 used for the fuse 100 of the present application, the flow area of ​​the melting zone 31 is smaller than that of the non-melting zone 32. The melting zone 31 is made of a first material, and the non-melting zone 32 is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material. Taking into account the influence of the mechanical properties of the material, a regionalized design of hardness and strength is adopted, which greatly alleviates and releases thermal stress, compensates for the defect of the weak structure of the melting zone 31, solves the problem of life damage under large pulse current, and enhances the fatigue resistance of the fuse 100.

[0057] In some embodiments, the first material comprises at least one of silver, copper, and a silver-copper alloy, and the second material is aluminum. For example, the metal strip used to process the melt 30 can be composed of multiple silver strips embedded in an aluminum base. Alternatively, the silver strips can be copper strips or a silver-copper alloy strip, which can achieve higher strength and hardness than the base. It is understood that in specific implementations, the aluminum strips can be replaced with a base material that is softer than silver or copper, such as nickel or tin, as long as sufficient electrical and thermal conductivity is ensured. Overall, at least one of the strength and hardness of the first material is greater than that of the second material. Typically, the first material can have both higher strength and hardness than the second material.

[0058] In the melt 30, the flow area of ​​the melting zone 31 is smaller than the flow area of ​​the non-melting zone 32, which can usually be achieved by punching the melting zone 31 to form punching holes, notches, weak parts, etc. Therefore, the melting zone 31 is also more likely to become a stress concentration area in the melt 30. Taking the power distribution system of the battery pack as an example, the fuse is an important part of the power distribution system of the battery pack, and its life is related to the safety and reliability of the entire battery pack. In order to ensure that the airtightness level of the battery pack reaches IP67 or higher (such as IP68), the fuse or distribution box is often located inside the battery pack, so the failure of the fuse will face high repair costs for the entire pack.

[0059] Nowadays, the discharge threshold of battery packs is getting higher and higher, causing the fuse to withstand higher peak currents. The high-temperature and closed environment further reduces the pulse resistance of the fuse. Once the fuse life reaches its limit, the protection function will fail and the circuit will become unstable, causing serious safety hazards.

[0060] This invention proposes a high-reliability, long-life, and low-cost fuse. By differentiating the strength and hardness of the materials in the melting and non-melting regions, the fuse element's overall resistance to alternating loads is enhanced. This ensures that the melting region has higher strength and hardness than the non-melting region, eliminating stress concentration caused by the sharp reduction in cross-sectional area in the melting region and distributing stress to the more flexible non-melting region, thereby improving the fuse element's fatigue resistance. This product can adapt to more intense and complex current environments, significantly extending the fuse's service life, offering significant cost advantages and the potential for large-scale industrial deployment.

[0061] For example, if the first material is silver and the second material is aluminum, the metal ribbon used to process the melt 30 can be made of multiple silver ribbons embedded in an aluminum ribbon matrix. The aluminum ribbon matrix forms the non-melting zone, while the silver ribbon forms the melting zone. The silver ribbon has higher strength and hardness than the aluminum ribbon matrix.

[0062] In a specific implementation, the melting region 31 and the non-melting region 32 are connected via a melt bonding process. Such melt bonding processes include rolling bonding, diffusion bonding, and brazing. Again, taking silver as the first material and aluminum as the second material, the silver ribbon is embedded in the aluminum ribbon matrix through rolling bonding, diffusion bonding, brazing, or other processes, thereby forming an electrical connection with the aluminum ribbon matrix. If rolling bonding is used, the silver and aluminum are tightly bonded through rolling. If diffusion bonding is used, the silver and aluminum interface can be diffused and bonded through high temperature and high pressure.

[0063] In some embodiments, the melt 30 is in the form of a sheet and includes a plurality of non-melting zones 32 and a plurality of melting zones 31 that are alternately arranged and connected in series. The melting zones 31 are formed with openings so that the flow area of ​​the melting zones 31 is smaller than the flow area of ​​the non-melting zones 32. There may be two non-melting zones 32 at both ends of the sheet-shaped melt 30 to facilitate electrical connection with the outside. Starting from one end, the non-melting zones 32 and the melting zones 31 are alternately distributed and connected in series according to the aforementioned materials and composite connection process. In this way, the non-melting zones of the melt 30 at both ends of its length constitute the connection ends.

[0064] The length of the melt is L and satisfies:

[0065] L=(N-1)d+2h=(u / W-1)d+2h

[0066] Wherein, N is the number of fuse zones; h is the length of the connection end; d is the distance between two adjacent fuse zones; u is the predetermined voltage value that the fuse can withstand; and W is the predetermined voltage value that each fuse zone can withstand. The units of L, d, and h are mm, and the units of u and W are volts (V). In specific applications, u is the predetermined voltage value that the fuse can withstand, which can be pre-set based on the application environment of the fuse 30 and is generally determined based on the rated voltage of the fuse 100.

[0067] In some embodiments, W ranges from 150V to 200V. Given this value, the total number of melting zones (N = u / W) can be calculated. The distance d between the melting zones is determined based on the diffusion of the metal vapor generated by the melt 30 during the breaking process and is generally within a range of 10mm to 20mm.

[0068] Optionally, along the length of the melt, the width of the melting zone is a, and the width of the non-melting zone is b, and they satisfy 10mm<a+b<20mm. The width of the melting zone 31 is a, and the width of the non-melting zone is b. Normally, a>2Φ. In order to accommodate deviations in the stamping process and ensure a larger ablation space after a short circuit (to ensure that the arc does not ablate the non-melting zone), the length of a can be increased, but this will increase the cost of raw materials. And d=a+b, so 10mm<a+b<20mm.

[0069] In a specific implementation, the aperture of the opening formed in the fusing zone is Φ, in mm, and satisfies a>2Φ.

[0070] In some embodiments, the non-melting region 32 between the melting regions 31 forms a bend with a predetermined angle.

[0071] Optionally, the bending angle is θ, and the value range of θ is 30°≤θ<180°. For example, in a specific implementation, the value of θ may be 30°, 60°, 90°, 120°, 150°, 160°, etc. The melt 30 contains one or more groups of melting zones 31 and non-melting zones 32 connected in series. The melting zone 31 has a small cross-sectional area, and the non-melting zone 32 has a large cross-sectional area. The non-melting zone 32 can further relieve stress concentration by bending. The applicant found through research and experiments that the stress concentration area of ​​the fuse after bending is dispersed from the melting zone to the bending point, and the effect of increasing the relaxation stress becomes more obvious as the stress increases.

[0072] The applicant further discovered through research and experiments that when θ is 90°, the stress relaxation effect is the best, and the narrow diameter obtains the minimum equivalent stress.

[0073] Specific reference Figures 7 to 13As shown, the applicant conducted pulse temperature tests under the same conditions using the same material and flattened dimensions, with the same non-melting zones at both ends of the melt 30 in the longitudinal direction forming the same connection end structure, except that the bending angle θ formed by the non-melting zone 32 located between the melting zones 31 was different, to obtain the equivalent stress test results of the melt. The melt length L = 75 mm, the melt width N = 3, the length of the connection h = 22.5 mm, d = the span between two adjacent melting zones, d = 15 mm, and the aperture of the opening formed by the melting zone is Φ = 2 mm. The material of the non-melting zone is aluminum, and the material of the melting zone is copper-silver alloy.

[0074] like Figure 7 As shown, the bending angle θ of the melt in this embodiment is 160°; Figure 8 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 150°; Figure 9 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 120°; Figure 10 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 90°; Figure 11 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 60°; Figure 12 : is an equivalent stress test diagram of the melt in one embodiment, wherein the bending angle θ is 30°.

[0075] Figure 13 for Figures 7 to 12 Figure 2 shows the test conditions used in the examples. The same test conditions were used in all examples: pulsed heating for 482.3 seconds with a 20-second cycle, with each cycle maintaining 271°C for 5 seconds and 171°C for 15 seconds. The equivalent stress distribution of the melt was then observed. As can be seen from the figure, the overall equivalent stress of the melt is minimized when the bending angle θ is 90°. This is converted to the following table.

[0076] Bending angle (°) <![CDATA[Equivalent stress (×10 9 MPa)]]> 30° 2.2213 60° 1.0029 90° 0.85088 120° 1.6803 150° 1.6102 160° 1.6899

[0077] This application also discloses an electrical device including the aforementioned fuse or the aforementioned cutout. The electrical device may be an energy storage device, a battery pack, or the like, or a power supply or power-consuming device equipped with such an energy storage device or battery pack. The device may be in any form, as long as it utilizes the aforementioned fuse 30 or cutout 100.

[0078] Throughout this specification, reference to the terms "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, for example, two or three, unless otherwise specifically defined.

[0080] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A fuse element for a fuse, characterized in that: include: Two non-fuse areas for forming a current flow path; and a fusing area connected between the two non-fusing areas and configured to fuse when the current exceeds a predetermined threshold; The overflow area of ​​the melting zone is smaller than that of the non-melting zone. The melting zone is made of a first material and the non-melting zone is made of a second material, and at least one of the strength and hardness of the first material is higher than that of the second material.

2. The melt according to claim 1, characterized in that The first material includes at least one of silver, copper, and silver-copper alloy, and the second material is aluminum.

3. The melt according to claim 1, characterized in that The melting area and the non-melting area are connected by a melt bonding process.

4. The melt according to claim 3, characterized in that The melt composite process includes rolling composite, diffusion composite and brazing.

5. The melt according to any one of claims 1 to 4, characterized in that: The melt is in sheet shape and comprises a plurality of non-melting areas and a plurality of melting areas which are alternately arranged and connected in series with each other, and the melting areas are formed with openings.

6. The melt according to claim 5, wherein: The non-melting areas of the melt at both ends of its length direction constitute the connection ends. The length of the melt is L and satisfies: L=(N-1)d+2h=(u / W-1)d+2h Among them, N is the number of the fuse zones; h is the length of the connection end; d is the span between two adjacent fuse zones; u is the predetermined voltage value that the fuse can withstand; W is the predetermined voltage value that each fuse zone can withstand; the units of L, d, and h are mm, and the units of u and W are V.

7. The melt according to claim 6, wherein: The value range of W is 150V-200V.

8. The melt according to claim 6, wherein: The span d ranges from 10 mm to 20 mm.

9. The melt according to claim 6, wherein: Along the length direction of the melt, the width of the melting zone is a, the width of the non-melting zone is b, and they satisfy 10 mm < a + b < 20 mm.

10. The melt according to claim 9, characterized in that: The aperture of the opening formed in the fusing zone is Φ, in mm, and satisfies a>2Φ.

11. The melt according to claim 5, wherein: The non-melting area located between the melting areas forms a bend with a predetermined angle.

12. The melt according to claim 11, wherein: The bending angle is θ, and the value range of θ is 30°≤θ<180°.

13. The melt according to claim 12, wherein: The θ is 90°.

14. A fuse, characterized in that: It comprises a first connecting terminal, a second connecting terminal and a fuse, wherein two ends of the fuse are electrically connected to the first connecting terminal and the second connecting terminal respectively; the fuse is the fuse according to any one of claims 1 to 13.

15. An electrical device, characterized in that: The invention comprises the melt according to any one of claims 1 to 13 or the fuse according to claim 14.

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