ULTRA-THIN MELABABLE FUSE

Abstract

Various protective devices and associated methods are disclosed. In some embodiments, a protective device may comprise a substrate and a fusible element extending between a first terminal and a second terminal, wherein the fusible element, the first terminal, and the second terminal are connected to the substrate. The protective device may further comprise a cover formed over the fusible element, wherein the fusible element is arranged between the cover and the substrate.

Description

Technical area

[0001] The present disclosure generally relates to the field of protective devices. More particularly, embodiments of the present disclosure relate to an ultra-thin fusible fuse. background

[0002] Fuses are typically used as circuit protection devices and form an electrical connection to a component in a circuit to be protected. A pair of conductors or terminals is often connected via a fusible element that bridges the terminals. However, some fuses take up too much space.

[0003] Accordingly, there is a need for a thin fuse that can be used to protect a battery while still maintaining the required electrical power. Summary

[0004] The abstract is intended to present a selection of concepts in a simplified form, with the concepts being described further below in the detailed description. The abstract is not intended to identify essential features of the claimed subject matter, nor is it intended to serve as a basis for determining the scope of the claimed subject matter.

[0005] In one embodiment, a protection device may comprise a substrate and a fusible element extending between a first terminal and a second terminal, wherein the fusible element, the first terminal, and the second terminal are connected to the substrate. The protection device may further comprise a cover formed over the fusible element, wherein the fusible element is disposed between the cover and the substrate.

[0006] In another embodiment, a method of manufacturing a protection device may comprise bonding a fusible element to a substrate, the fusible element extending between a first terminal and a second terminal, and forming a cover over the fusible element, the fusible element being disposed between the cover and the substrate. Short description of the characters

[0007] The accompanying figures show exemplary concepts of the disclosed embodiments developed for practical application of its principles, and wherein: Fig. 1 shows a perspective view of a protective device according to embodiments of the present disclosure; Fig. 2 shows a perspective detailed view of the protective device of Fig. 1 according to embodiments of the present disclosure; Fig. Figure 3 shows another perspective view of the protective device of Fig. 1, according to embodiments of the present disclosure; Fig. 4 shows a perspective view of a protective device according to embodiments of the present disclosure; Fig. 5 shows a perspective detailed view of the protective device of Fig. 4 according to embodiments of the present disclosure; Fig. Figure 6 shows another perspective view of the protective device of Fig. 4, according to embodiments of the present disclosure; Fig. 7 - 8 show perspective views of the protective device of Fig. 4 with a plurality of plating layers according to embodiments of the present disclosure; Fig. 9 shows a flowchart of a method for manufacturing the protective device of the Fig. 1-3, according to embodiments of the present disclosure; Fig. 10 shows a flowchart of a method for manufacturing the protective device of the Fig. 4-8, according to embodiments of the present disclosure; Fig. 11-12 show perspective views of a protective device according to embodiments of the present disclosure; and Fig. 13 shows a perspective detailed view of the protective device of the Fig. 11-12, according to embodiments of the present disclosure.

[0008] The drawings are not necessarily to scale. The drawings are merely illustrations and are not intended to depict specific parameters of the disclosure. The drawings are intended to illustrate exemplary embodiments of the disclosure and are therefore not to be considered limiting of the scope of protection. Like reference numerals refer to like features throughout the drawings.

[0009] In addition, certain features may be omitted or not drawn to scale in some of the figures for clarity of illustration. The cross-sectional views may be presented as "sections" or "close-ups" of the cross-sectional view, with certain background lines that would be visible in a "true" cross-sectional view omitted for clarity. In addition, some reference numerals may be omitted from certain drawings for clarity. DETAILED DESCRIPTION

[0010] Protection devices, fuse assemblies, and methods in accordance with the present disclosure are described in more detail below with reference to the accompanying figures, in which embodiments are illustrated. The protection devices, fuse assemblies, and methods may be embodied in many different forms and should not be construed as limited to the embodiments illustrated herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0011] Embodiments of the present disclosure provide an ultra-thin fusible solution for battery protection applications using a flexible polyimide substrate material. The fuse is flexible and achieves an ultra-thin profile of less than about 0.4 mm. Electrical performance can be optimized by modifying the pattern of the fusible element extending between the terminals. In some examples, a polyamide (PI) quad can be used as the substrate, where the element can be formed by photolithography and chemical etching and then covered with a liquid photoimaging (LPI) mask material. The terminals can be fusible and can be achieved by exposing the Cu on the terminals by laser stripping the polyimide layer.

[0012] In another example, instead of laser stripping the Cu terminal, PCB rivets can be installed to create an electrical connection and mechanically secure the Cu strips, which then serve as fusible links and an extended fuse terminal. Tin (Sn) plated fuse terminals can optionally be provided for additional metallic connection, with plating being performed by immersion.

[0013] Fig. 1-3 illustrate a protective device (hereinafter "device") 100 according to embodiments of the present disclosure. As illustrated, the device 100 may have a first main side 101 opposite a second main side 102 and a first end 103 opposite a second end 104. The device 100 may include a metal layer 108 (e.g., copper) formed into a fusible element 112, a first terminal 114, and a second terminal 116. It will be appreciated that the fusible element 112 is not limited to any particular shape or configuration. For example, although illustrated and described herein as straight or substantially straight, the fusible element 112 may also be curved, slanted, or bent. There may also be more than one fusible element 112. The embodiments described herein are not limited in this regard.

[0014] In accordance with known electrical fuses, the fusible element 112 is designed to melt, vaporize, disintegrate, or otherwise structurally fail when a predetermined current flows through the fuse for a specified period of time, sometimes referred to as an overcurrent condition that can damage sensitive electronic components. That is, the current path through the device 100 is designed to fail, opening the current path through the fusible element 112 to prevent damage to sensitive circuit components. The current that the fusible element 112 can withstand before opening the current path can vary depending on its particular material properties and dimensions. For this purpose, various designs of fuses or fusible elements are known.Once the fusible link 112 is opened, the fuse assembly 102 can be replaced to restore the electrical circuit to full functionality.

[0015] The device 100 may further include a substrate 120, with the metal layer 108 connected to a top surface 122 of the substrate 120. In some embodiments, the first terminal 114 may extend beyond a first end 124 of the substrate 120, and the second terminal 116 may extend beyond a second end 126 of the substrate 120. The substrate 120 may be a polyamide substrate.

[0016] As further illustrated in the figure, the device 100 may include a cover 130 that extends over the fusible element 112. In other words, the metal layer 108 may be disposed between the substrate 120 and the cover 130. As illustrated, the cover 130 may further extend over the first terminal 114 and the second terminal 116. The cover 130 may have similar dimensions (e.g., in the x- and y-directions) to the substrate 120, but is not limited thereto. In some embodiments, the cover 130 may be a liquid photoimaging mask, silicone, and / or other polymers. After assembly, the device 100 may have a thickness (in the z-direction) of less than 0.4 mm. A method of manufacturing the device 100 is described below.

[0017] In some embodiments, device 100 may further include a metal element 133, which may be a Metcalf-effect (M-effect) coating of Sn applied to one or more surfaces of fusible element 112. During overload heating, the Sn of metal element 133 and the Cu of fusible element 112 diffuse together and attempt to form a eutectic material, resulting in a lower melting temperature in the region of metal element 133.

[0018] Fig. 4-6 illustrate another protective device (hereinafter "device") 200 according to embodiments of the present disclosure. As illustrated, the device 200 may include a metal layer 208 (e.g., copper) formed into a fusible element 212, a first terminal 214, and a second terminal 216. It will be appreciated that the fusible element 212 is not limited to any particular shape or configuration. For example, although illustrated and described herein as straight or substantially straight, the fusible element 212 may also be curved, slanted, or bent. There may also be more than one fusible element 212. The embodiments described herein are not limited in this context.

[0019] The device 200 may further include a substrate 220, with the metal layer 208 connected to a top surface 222 of the substrate 220. In some embodiments, the first terminal 214 may extend beyond a first end 224 of the substrate 220, and the second terminal 216 may extend beyond a second end 226 of the substrate 220. The substrate 220 may be a polyamide substrate.

[0020] As further shown, the device 200 may include a cover 230 extending over the fusible element 212, wherein the metal layer 208 may be located between the substrate 220 and the cover 230. In some embodiments, the cover 230 may further extend over the first terminal 214 and the second terminal 216. The cover 230 may have similar dimensions (e.g., in the x- and y-directions) as the substrate 220, but is not limited to this. In some embodiments, the cover 230 may be a liquid photoimaging mask.

[0021] In some embodiments, the device 200 may further include a metal element 233, which may be a Metcalf effect (M-effect) coating of Sn applied to one or more surfaces of the fusible element 212.

[0022] As in Fig. 5, the substrate 220 may have a first plurality of openings 240, the metal layer 208 may have a second plurality of openings 242, and the cover 230 may have a third plurality of openings 246. One or more fasteners 250 (e.g., rivets) may be disposed through each of the openings to interconnect the layers of the device 200. The fasteners 250 may also electrically connect to the first and second terminals 214, 216. A method of manufacturing the device 200 is described below.

[0023] As in Fig. 7-8, in some embodiments, the device 200 (and / or the device 100) may include one or more plating layers 255 formed on opposite sides of the cover 230 and the substrate 220. The plating layers 255 provide an additional metallic connection and may also be secured by the fasteners 250. The plating layers 255 may be electrically and physically connected to the first terminal 214 and the second terminal 216 of the metal layer 208. In some embodiments, the plating layers 255 may be comprised of Ni and Sn and / or Sn.

[0024] In Fig. 9, a method 300 for manufacturing device 100 will now be described in more detail. At block 301, method 300 may include preparing fusible element 112. In some embodiments, fusible element 112 is manufactured using a lamination, imaging, and fabrication process.

[0025] In block 302, the method 300 may include etching a layer of copper 108 to form the fusible element 112 based on the process preparation step.

[0026] In block 303, method 300 may include performing a selective SN dot coating process to form metal element 133, and in block 304, method 300 may include forming cap 130 over fusible element 112. In some embodiments, cap 130 may be an LPI cap formed by a spray, exposure, development, and then curing process. Alternatively, in block 304A, method 300 may include forming cap 130 using a polyamide press lamination process.

[0027] In block 305, the method 300 may include a mark formation process that may include a series of spraying, exposing, developing, and curing steps.

[0028] At block 306, method 300 may include removing a portion of cover 130 over first terminal 114 and second terminal 116. In some embodiments, cover 130 is removed using a polyamide laser stripping process.

[0029] In block 307, the method 300 may include performing a singulation process.

[0030] In Fig. 10, a method 400 for manufacturing device 200 will now be described in more detail. At block 401, method 400 may include preparing fusible element 212. In some embodiments, fusible element 212 is manufactured using a lamination, imaging, and fabrication process.

[0031] In block 402, the method 400 may include etching a layer of copper 208 to form the fusible element 212, followed by performing a selective SN dot plating process to form the metal element 233 in block 403.

[0032] At block 404, method 400 may include forming the cover 230 over the fusible element 212. The cover 230 may be an LPI cover formed using a spray, exposure, development, and then curing process. Alternatively, at block 404A, method 400 may include forming the cover 230 using a polyamide press lamination process.

[0033] In block 405, the method 400 may include a mark formation process that may include a series of spraying, exposing, developing, and curing steps.

[0034] In block 406, a singulation process may be performed, followed by a lead assembly process in block 407. In some embodiments, the plurality of rivets 250 are applied through the various layers of the device 200.

[0035] In block 408, an optional plating process may be performed. The plating layers may be Ni and Sn and / or Sn formed over the first terminal 214 and over the second terminal 216.

[0036] Fig. 11-13 show another protective device (hereinafter "device") 500 according to embodiments of the present disclosure. The device 500 may be the same or similar in some aspects to the other devices described herein. Therefore, for brevity, only certain aspects of the device 500 are described below. As shown, the device 500 may include a fusible element 512, a first terminal (or lead) 514, and a second terminal (or lead) 516. As shown in Fig. As best illustrated in Figure 13, the fusible element 512 may include a thinned central portion 521 extending between a first flange 523 and a second flange 525. Other shapes and configurations are possible in alternative embodiments.

[0037] The device 500 may further include a substrate 520, with the fusible element 512 connected to a top surface of the substrate 520. In some embodiments, the first terminal 514 may be adjacent to a first end 537 of the substrate 520 and a second end 526 of the substrate 520. In the illustrated embodiment, the substrate 520 may be a polyamide substrate.

[0038] As further shown, the device 500 may include a cover 530 extending over the fusible element 512, where the fusible element 512 may be enclosed by the substrate 520 and the cover 530. In some embodiments, the cover 530 may further extend over the first terminal 514 and the second terminal 516. The cover 530 may be larger (e.g., in the x-direction) than the substrate 520, but is not limited to this. In some embodiments, the cover 530 may be a liquid photoimaging mask.

[0039] As in Fig. 13, the device 200 may further include a metal element 533, which may be a Metcalf effect (M-effect) coating of Sn applied to one or more surfaces of the fusible element 512. As further illustrated, the first terminal 514 may include a first plurality of openings 540A, the second terminal 516 may include a second plurality of openings 540B, the fusible element 512 may include a third plurality of openings 542, and the cover 530 may include a fourth plurality of openings 546. One or more fasteners 550 (e.g., rivets) may be disposed through each of the openings to interconnect the layers of the device 500. The fasteners 550 may also provide electrical connection to the first and second terminals 514, 516.

[0040] When a feature or step is mentioned herein in the singular and begins with the word "a" or "an," this should not be understood as excluding features or steps in the plural unless such exclusion is expressly stated. Furthermore, references to "one embodiment" of the present disclosure should not be understood as excluding the existence of additional embodiments that also include the mentioned features.

[0041] The use of "include," "comprising," or "with," and variations thereof, is intended to encompass the elements listed below and their equivalents, as well as additional features. Accordingly, the terms "include," "comprising," or "with," and variations thereof, are open-ended terms and may be used interchangeably herein.

[0042] The terms "at least one," "one or more," and "and / or," as used herein, are indefinite terms and may be used both conjunctively and disjunctively. For example, the terms "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" mean A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.

[0043] All directional terms (e.g., proximal, distal, upper, lower, above, below, left, right, lateral, longitudinal, front, rear, above, below, up, down, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are used for identification purposes only to assist the reader in understanding the present disclosure. The directional terms are not limitations, particularly with respect to the location, orientation, or use of the disclosure. References to connections (e.g., attached, coupled, connected, and joined) should be interpreted broadly and may include intermediaries between a collection of elements and relative movement between elements, unless otherwise noted. The terms "connection" do not necessarily imply that two elements are directly connected and in a fixed relationship.

[0044] Furthermore, identifying cues (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to convey importance or priority, but are used to distinguish one feature from another. The drawings are for illustrative purposes, and the dimensions, positions, sequence, and relative sizes shown in the accompanying drawings may vary.

[0045] Furthermore, the terms "substantial" or "approximate," as well as the terms "approximately" or "approximately," may be used interchangeably in some embodiments and may be described using any relative measure acceptable to one of ordinary skill in the art. These terms may, for example, serve as a comparison to a reference parameter to indicate a deviation that can perform the intended function. The deviation from the reference parameter may, for example, be less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, etc.

[0046] Furthermore, the terms "substantial" or "approximate," as well as the terms "approximately" or "approximately," may be used interchangeably in some embodiments and may be described using any relative measure acceptable to one of ordinary skill in the art. These terms may, for example, serve as a comparison to a reference parameter to indicate a deviation that can achieve the intended function. The deviation from the reference parameter may be, for example, less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, etc., but is not limited.

Claims

[1] Protective device comprising: a substrate; a fusible element extending between a first terminal and a second terminal, the fusible element, the first terminal, and the second terminal being connected to the substrate; and a cover formed over the fusible element, the fusible element being disposed between the cover and the substrate. [2] The protective device according to claim 1, wherein the cover is partially formed over the first terminal and the second terminal. [3] The protective device of claim 1, wherein the cover is a liquid photo-imaging mask, a silicone mask, or a polymer mask. [4] The protective device according to claim 1, wherein the substrate is a polyimide substrate. [5] The protective device of claim 1, further comprising a plurality of fasteners interconnecting the cover, the substrate, and the fusible element. [6] The protection device according to claim 1, further comprising a plating layer formed over the first and second terminals. [7] The protective device according to claim 1, further comprising a tin layer formed on the fusible element. [8] A method of manufacturing a protective device comprising: Connecting a fusible element to a substrate, the fusible element extending between a first terminal and a second terminal; and Forming a cover over the fusible element, wherein the fusible element is arranged between the cover and the substrate. [9] The method of claim 8, further comprising partially forming the cover over the first terminal and the second terminal. [10] The method of claim 8, wherein the cover is a liquid photo-imaging mask. [11] The method of claim 8, wherein the substrate is a polyimide substrate. [12] The method of claim 8, further comprising bonding the cover of the substrate and the fusible element using a plurality of fasteners. [13] The method of claim 12, wherein the plurality of fasteners are rivets. [14] The method of claim 8, further comprising forming a plating layer over the first and second terminals. [15] The method according to claim 14, wherein the plating layer is formed by dipping the first terminal and the second terminal in tin. [16] The method of claim 8, further comprising partially removing the cover to expose the first terminal and the second terminal. [17] The method of claim 16, wherein the cover is removed by a laser stripping process.

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