Coil component

Abstract

The present disclosure provides a coil component including: a body including a first surface and a second surface opposite to each other in a first direction and a third surface and a fourth surface opposite to each other in a second direction perpendicular to the first direction; the coil comprises a winding part arranged in the main body and a leading-out part extending to the main body from the end part of the winding part; and an external electrode disposed on the main body, the external electrode having an inner surface facing the main body and an outer surface opposite the inner surface. The external electrode includes a protruding portion protruding toward the main body, and the lead-out portion is in contact with the inner surface of the external electrode.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0112172, filed on August 21, 2024, with the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0201608, filed on December 31, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a coil assembly. Background Technology

[0003] An inductor (a coil assembly) is a typical passive electronic component used in electronic devices, along with resistors and capacitors. The coil regulates the flow of current, eliminates noise, and prevents sudden changes in current, thereby protecting the electronic device.

[0004] As the performance of electronic devices gradually improves and their size gradually decreases, the number of electronic components used in electronic devices increases and their size decreases.

[0005] As the number of electronic devices used in vehicles increases, especially those directly mounted in the engine compartment, there is a growing need for enhanced vibration resistance in inductors.

[0006] Patent document 1: Korean patent application No. 10-2017-0085895 published. Summary of the Invention

[0007] One aspect of this disclosure is to provide a coil assembly that has improved vibration resistance by enhancing the solder feet formed by solder when mounted on a board via protrusions (including Sn) formed on the base of the outer electrode.

[0008] Another aspect of this disclosure is to provide a coil assembly that, when mounted on a plate, has enhanced mounting strength through protrusions formed on the pad portion of the outer electrode.

[0009] Another aspect of this disclosure is that the position of the lead-out portion is guided by a plurality of protrusions formed on the external electrode.

[0010] Another aspect of this disclosure is to prevent movement of the outer electrode by maintaining a predetermined distance between the body and the outer electrode through a plurality of protrusions formed on the outer electrode.

[0011] According to one aspect of this disclosure, a coil assembly is provided, comprising: a body including a first surface and a second surface opposing each other in a first direction, and a third surface and a fourth surface opposing each other in a second direction perpendicular to the first direction; a coil including a winding portion disposed in the body and a lead-out portion extending from an end of the winding portion onto the body; and an external electrode disposed on the body, the external electrode having an inner surface facing the body and an outer surface opposing the inner surface. The external electrode may include a protrusion projecting toward the body, and the lead-out portion may contact the inner surface of the external electrode.

[0012] According to another aspect of this disclosure, a coil assembly is provided, the coil assembly including a body, a coil disposed in the body, and an external electrode disposed on the body, the coil including a lead-out portion, the external electrode being connected to the lead-out portion, the external electrode including a plurality of protrusions. The lead-out portion may be disposed between a first protrusion and a second protrusion that are adjacent to each other among the plurality of protrusions.

[0013] According to another aspect of this disclosure, a coil assembly is provided, the coil assembly comprising: a body including a first surface and a second surface opposite to each other in a first direction and a third surface and a fourth surface opposite to each other in a second direction perpendicular to the first direction; a coil including a winding portion embedded in the body and a lead-out portion extending from an end of the winding portion to an outer surface of the body along the first direction; and an external electrode disposed on the body, wherein a portion of the lead-out portion is located between the external electrode and the first surface and / or the second surface of the body.

[0014] According to some example embodiments of this disclosure, the protrusion formed on the base of the outer electrode of the coil assembly may include Sn. Therefore, the coil assembly can have improved vibration resistance by enhancing the solder feet formed by solder when mounted on a board.

[0015] According to some example embodiments of this disclosure, the coil assembly may have enhanced mounting strength when mounted on a board by protrusions formed on the pad portion of the outer electrode.

[0016] According to some example embodiments of this disclosure, the position of the lead-out portion can be guided by a plurality of protrusions formed on the external electrode.

[0017] According to some exemplary embodiments of this disclosure, a predetermined distance can be maintained between the body and the external electrode by forming a plurality of protrusions on the external electrode, thereby preventing the external electrode from moving. Attached Figure Description

[0018] The above and other aspects, features and advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic perspective view of a coil assembly according to a first exemplary embodiment of the present disclosure; Figure 2 It is along Figure 1 A cross-sectional view taken from line I-I'; Figure 3 yes Figure 2 A magnified view of region "A"; Figure 4 yes Figure 2 A magnified view of region "B"; Figure 5 It is along Figure 1 A partial cross-sectional view taken from line II-II'; Figure 6 This is a schematic diagram illustrating the process of forming a coil and an external electrode of a coil assembly according to a second exemplary embodiment of the present disclosure; Figure 7 yes Figure 1 An exploded perspective view, showing the form of the outer electrode before bending; Figures 8 to 11 It is shown Figure 5 A diagram illustrating the variation in the cross-sectional shape of the protrusion; Figure 12 This is a diagram showing the lead-out portion and external electrode of a coil assembly according to a second exemplary embodiment of the present disclosure; Figure 13 This is a diagram showing the lead-out portion and external electrode of a coil assembly according to a third exemplary embodiment of the present disclosure; Figure 14 This is a diagram showing the lead-out portion and external electrode of a coil assembly according to a fourth exemplary embodiment of the present disclosure; Figure 15 This is a schematic perspective view of a coil assembly according to a fifth exemplary embodiment of the present disclosure; Figure 16 It is along Figure 15 A cross-sectional view taken from line III-III'; Figure 17 This is a diagram showing the lead-out portion and external electrode of a coil assembly according to a sixth exemplary embodiment of the present disclosure; Figure 18 This is a diagram showing the lead-out portion and external electrode of a coil assembly according to a seventh exemplary embodiment of the present disclosure; Figure 19 It is shown that from Figure 1 A schematic diagram showing the form of a fillet when a coil assembly with protrusions is mounted on a board, omitting the actual fillet. Figure 20 It shows when Figure 1 A schematic diagram showing the form of the reinforced solder feet when the coil assembly is mounted on the board; Figure 21 This is an experimental example demonstrating the form of solder joints when a coil assembly excluding protrusions is mounted on a board; Figure 22 This is an experimental example illustrating the form of solder joints when a coil assembly including protrusions is mounted on a board; and Figure 23 This is an example showing the simulation results based on stress changes according to weld formation and weld reinforcement. Detailed Implementation

[0019] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any one and any combination of any two or more of the associated listed items. It will also be understood that, when used in this specification, the terms "comprising" and / or "including" specify the presence of the mentioned features, quantities, steps, operations, elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, and / or combinations thereof. Additionally, the terms "set on," "located on," etc., may indicate that an element is located above or below a target portion, and do not necessarily mean that the element is positioned on top of the target portion relative to a direction opposite to the direction of gravity.

[0020] The terms “integrated into” and “connected to” can refer not only to elements that are in direct and physical contact with each other, but also to a structure in which another element is located between the elements, such that the elements are in contact with the other element.

[0021] For ease of description, dimensions (such as thickness) of each element shown in the accompanying drawings are arbitrarily represented, but this disclosure is not limited to the dimensions (such as thickness) shown herein.

[0022] In the attached figures, the L direction can be defined as a first direction (1) or a length direction, the T direction can be defined as a second direction (2) or a thickness direction, and the W direction can be defined as a third direction (3) or a width direction.

[0023] In the following description, coil assemblies according to some exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description with reference to the drawings, the same elements are indicated by the same reference numerals and repeated descriptions thereof will be omitted.

[0024] Various types of electronic components can be used in electronic devices, and various types of coil components can be appropriately used between these electronic components to remove noise.

[0025] That is, in electronic devices, coil assemblies can be used as power inductors, high-frequency (HF) inductors, ordinary ferrite beads, high-frequency ferrite beads (e.g., ferrite beads for the GHz band), common-mode filters, etc.

[0026] First Example Implementation Figure 1 This is a schematic perspective view of a coil assembly according to a first exemplary embodiment of the present disclosure. Figure 2 It is along Figure 1 The cross-sectional view taken from line I-I'. Figure 3 yes Figure 2 A magnified view of region "A". Figure 4 yes Figure 2 A magnified view of region "B". Figure 5 It is along Figure 1 A partial cross-sectional view taken from line II-II'.

[0027] exist Figure 1 In the middle, the main body 100 is shown in a transparent manner to clearly show the arrangement relationship between the components.

[0028] Reference Figures 1 to 5 According to a first exemplary embodiment of the present disclosure, the coil assembly 1000 may include a body 100, a coil 200, a first external electrode 300, and a second external electrode 400. The first external electrode 300 and the second external electrode 400 may each include at least one protrusion 350 and at least one protrusion 450 projecting toward the body 100, respectively. The protrusions 350 and 450 may be formed on the bases 310 and 410 of the side surfaces of the external electrodes 300 and 400 facing the body 100, and / or on the pads 330 and 430 of the external electrodes 300 and 400 facing the lower surfaces of the body 100, respectively.

[0029] The protrusions 350 and 450 may include a first metal layer ML1 projecting toward the body 100 and a second metal layer ML2 filling a recessed area formed on the outer surface of the first metal layer ML1. The second metal layer ML2 may include Sn. Due to the above structure, during the reflow soldering process of mounting the coil assembly 1000 onto the board, the second metal layer ML2 formed in the protrusions 350 and 450 on the bases 310 and 410 can flow downwards, thereby reinforcing the solder feet with solder. The reinforced solder feet can enhance the bonding force between the board and the coil assembly 1000 by relieving the stress applied to the coil assembly 1000, and thus improve the shock resistance and vibration resistance of the coil assembly 1000.

[0030] Furthermore, leads 221 and 222 at both ends of coil 200 may be disposed between the main body 100 and the outer electrodes 300 and 400 to contact the inner surfaces of the outer electrodes 300 and 400, respectively, and may be disposed between a pair of protrusions (e.g., 350a and 350b, 450a and 450b) formed on the inner surfaces of the bases 310 and 410 and / or the pads 330 and 430. Therefore, since leads 221 and 222 are disposed between a pair of adjacent protrusions (e.g., 350a and 350b, 450a and 450b) formed on the inner surfaces of the bases 310 and 410 and / or the pads 330 and 430, the positions of leads 221 and 222 can be guided. As an example, the first protrusion 350a and the second protrusion 350b may be disposed on both sides of the first lead-out portion 221 in the third direction (e.g., disposed opposite to each other, i.e., the first protrusion 350a and the second protrusion 350b may at least partially overlap in the third direction), and the third protrusion 450a and the fourth protrusion 450b may be disposed on both sides of the second lead-out portion 222 in the third direction (e.g., disposed opposite to each other, i.e., the third protrusion 450a and the fourth protrusion 450b may at least partially overlap in the third direction). Each of the first protrusion 350a and the second protrusion 350b may be disposed on the first base 310 or the first pad portion 330, or one of the first protrusion 350a and the second protrusion 350b may be disposed on the first base 310 and the other on the first pad portion 330. Each of the third protrusion 450a and the fourth protrusion 450b may be disposed on the second base 410 or the second pad 430, or one of the third protrusion 450a and the fourth protrusion 450b may be disposed on the second base 410 and the other on the second pad 430. Each of the first protrusion 350a, the second protrusion 350b, the third protrusion 450a, and the fourth protrusion 450b may be multiple.

[0031] The main elements included in the coil assembly 1000 according to this example embodiment will be described in detail below.

[0032] The body 100 may form the appearance of the coil assembly 1000 according to this example embodiment, and may include a coil 200 embedded therein.

[0033] The main body 100 can have a hexahedral shape as a whole.

[0034] The body 100 may have a first surface 101 and a second surface 102 that are opposite each other in the length direction L (first direction), a third surface 103 and a fourth surface 104 that are opposite each other in the thickness direction T (second direction), and a fifth surface 105 and a sixth surface 106 that are opposite each other in the width direction W (third direction). Each of the first surface 101, the second surface 102, the fifth surface 105, and the sixth surface 106 of the body 100 may correspond to a wall surface of the body 100 that connects the third surface 103 and the fourth surface 104 of the body 100 to each other.

[0035] For example, the body 100 may be configured such that the coil assembly 1000, including external electrodes 300 and 400 according to this example embodiment, has a length of 6.47 mm, a width of 6.47 mm, and a thickness of 2.8 mm, or has a length of 5.2 mm, a width of 5.2 mm, and a thickness of 2.8 mm. The dimensions described above refer to dimensions that do not reflect manufacturing tolerances. Therefore, any dimension falling within what is considered to be a manufacturing tolerance should be considered to correspond to the exemplary dimensions described above.

[0036] Regarding optical microscopic images or scanning electron microscopy (SEM) images of cross-sections in the length direction L and thickness direction T obtained by cutting the coil assembly 1000 at its central portion in the width direction W, the aforementioned length of the coil assembly 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting the two outermost boundary lines of the coil assembly 1000 shown in the image that are opposite each other in the length direction L to be parallel to the length direction L, and the plurality of line segments being spaced apart from each other in the thickness direction T. Optionally, the aforementioned length of the coil assembly 1000 may refer to the minimum value of the dimensions of the plurality of line segments. Optionally, the aforementioned length of the coil assembly 1000 may refer to the arithmetic mean of at least three dimensions of the plurality of line segments. Here, the plurality of line segments parallel to the length direction L may be equidistant from each other in the thickness direction T, but this disclosure is not limited thereto.

[0037] For optical microscopic or SEM images of cross-sections in the length direction L and thickness direction T obtained by cutting the coil assembly 1000 at its central portion in the width direction W, the aforementioned thickness of the coil assembly 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting the two outermost boundary lines of the coil assembly 1000 shown in the image that are opposite each other in the thickness direction T to be parallel to the thickness direction T, and the plurality of line segments being spaced apart from each other in the length direction L. Optionally, the aforementioned thickness of the coil assembly 1000 may refer to the minimum value of the dimensions of the plurality of line segments. Optionally, the aforementioned thickness of the coil assembly 1000 may refer to the arithmetic mean of at least three dimensions of the plurality of line segments. Here, the plurality of line segments parallel to the thickness direction T may be equidistant from each other in the length direction L, but this disclosure is not limited thereto.

[0038] For optical microscopic or SEM images of cross-sections in the length direction L and width direction W obtained by cutting the coil assembly 1000 at its central portion in the thickness direction T, the aforementioned width of the coil assembly 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting the two outermost boundary lines of the coil assembly 1000 shown in the image that are opposite each other in the width direction W to be parallel to the width direction W, and the plurality of line segments being spaced apart from each other in the length direction L. Optionally, the aforementioned width of the coil assembly 1000 may refer to the minimum value of the dimensions of the plurality of line segments. Optionally, the aforementioned width of the coil assembly 1000 may refer to the arithmetic mean of at least three dimensions of the plurality of line segments. Here, the plurality of line segments parallel to the width direction W may be equidistant from each other in the length direction L, but this disclosure is not limited thereto.

[0039] Optionally, the length, width, and thickness of the coil assembly 1000 can be measured using a micrometer. Each of the length, width, and thickness of the coil assembly 1000 can be measured using a micrometer with gage repeatability and reproducibility (R&R) by setting a zero point, inserting the coil assembly 1000 according to this example embodiment between the tips of the micrometer, and rotating the measuring rod of the micrometer. When measuring the length of the coil assembly 1000 using a micrometer, the length of the coil assembly 1000 can refer to a single measurement or the arithmetic mean of multiple measurements; the same applies to the measurement of the width and thickness of the coil assembly 1000.

[0040] The body 100 may include magnetic material and resin. The body 100 can be formed by filling a mold with magnetic material, and can also be formed by filling a mold with a composite material including magnetic material and resin. A molding process of magnetic material or composite material in which high temperature and high pressure are applied to the mold may also be performed, but this disclosure is not limited thereto.

[0041] Reference Figure 7 In the body 100, for example, bodies 100a and 100b (both the upper and lower regions above and below the coil 200) may be formed separately and may be combined with each other to form a single body 100. In this case, bodies 100a and 100b (both the upper and lower regions) may have different densities depending on the forming temperature or pressure, and the components included in bodies 100a and 100b may be partially different from each other, but this disclosure is not limited thereto.

[0042] The magnetic material included in the main body 100 can be ferrite particles or magnetic metal particles.

[0043] Ferrite particles may include, for example, at least one selected from the group consisting of spinel-type ferrite particles (such as Mg-Zn-based ferrite particles, Mn-Zn-based ferrite particles, Mn-Mg-based ferrite particles, Cu-Zn-based ferrite particles, Mg-Mn-Sr-based ferrite particles, Ni-Zn-based ferrite particles, etc.), hexagonal ferrite particles (such as Ba-Zn-based ferrite particles, Ba-Mg-based ferrite particles, Ba-Ni-based ferrite particles, Ba-Co-based ferrite particles, Ba-Ni-Co-based ferrite particles, etc.), garnet-type ferrite particles (such as yttrium (Y)-based ferrite particles, etc.) and Li-based ferrite particles.

[0044] Magnetic metal particles may include one or more selected from the group consisting of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), and nickel (Ni). For example, magnetic metal particles may include at least one selected from the group consisting of pure iron particles, Fe-Si based alloy particles, Fe-Si-Al based alloy particles, Fe-Ni based alloy particles, Fe-Ni-Mo based alloy particles, Fe-Ni-Mo-Cu based alloy particles, Fe-Co based alloy particles, Fe-Ni-Co based alloy particles, Fe-Cr based alloy particles, Fe-Cr-Si based alloy particles, Fe-Si-Cu-Nb based alloy particles, Fe-Ni-Cr based alloy particles, and Fe-Cr-Al based alloy particles.

[0045] The magnetic metal particles can be amorphous or crystalline. For example, the magnetic metal particles may include Fe-Si-B-Cr based amorphous alloy particles, but this disclosure is not limited thereto.

[0046] Each of the ferrite particles and magnetic metal particles may have an average diameter of about 0.1 μm to about 30 μm, but this disclosure is not limited thereto.

[0047] The body 100 may include two or more types of magnetic materials dispersed in the resin. Here, different types of magnetic materials mean that the magnetic materials dispersed in the resin are distinguished from each other by their average diameter, composition, crystallinity, and / or shape.

[0048] The resin may include at least one of epoxy resin, polyimide resin, liquid crystal polymer, etc., but this disclosure is not limited thereto.

[0049] The main body 100 may include the core 110. (See reference...) Figure 2 and Figure 7 The core 110 may refer to the area of ​​the body 100 that is filled to pass through the hollow core of the coil 200. Specifically, the core 110 may be disposed in the internal region of the winding portion 210 forming at least one turn, and the cross section of the core 110 perpendicular to the winding axis of the winding portion 210 may have a circular or elliptical shape, but this disclosure is not limited thereto.

[0050] Reference Figure 1 , Figure 2 and Figure 7 The main body 100 may include recesses R1 and R2. The first recess R1 may be formed in the region where the first surface 101 and the third surface 103 of the main body 100 are connected to each other (a portion of the first surface 101 and a portion of the third surface 103 of the main body), and the second recess R2 may be formed in the region where the second surface 102 and the third surface 103 of the main body 100 are connected to each other (a portion of the second surface 102 and a portion of the third surface 103 of the main body).

[0051] According to this example embodiment, the recesses R1 and R2 correspond to the regions in which a step difference is formed towards the interior of the body 100 to accommodate the leads 221 and 222 and the external electrodes 300 and 400. For ease of description, the regions in which the recesses R1 and R2 are formed can be defined as also including the first surface 101, the second surface 102, and the third surface 103.

[0052] In some embodiments, the external electrodes 300 and 400 may include bases 310 and 410, pads 330 and 430, and insertion portions 320 and 420. The bases 310 and 410 of the external electrodes 300 and 400 may be disposed in recesses R1 and R2 formed in the first surface 101 and the second surface 102, and the pads 330 and 430 of the external electrodes 300 and 400 may be disposed in recesses R1 and R2 formed in the third surface 103. That is, the external electrodes 300 and 400 may be bent along the shape of the recesses R1 and R2 and disposed on the body 100. Additionally, the insertion portions 320 and 420 of the external electrodes 300 and 400 may be inserted into the body 100 through the recesses R1 and R2. Furthermore, in this example embodiment, the protrusions 350 and 450 of the external electrodes 300 and 400 may contact the surface of the body where the recesses are formed. In some embodiments, at least one protrusion 350 may contact a first surface of the body having a recess, and at least one protrusion 350 may contact a third surface of the body having a recess. In some embodiments, at least one protrusion 450 may contact a second surface of the body having a recess, and at least one protrusion 450 may contact a third surface of the body having a recess.

[0053] In some embodiments, the body 100 may not have a recess, so the leads 221 and 222 and the external electrodes 300 and 400 may be provided on the body to protrude from the flat surface of the body 100, but this disclosure is not limited thereto.

[0054] The coil 200 can be embedded in the body 100 to exhibit the characteristics of the coil assembly 1000. For example, when the coil assembly 1000 according to this example embodiment is used as a power inductor, the coil 200 can store an electric field as a magnetic field to maintain the output voltage, thereby stabilizing the power of the electronic device.

[0055] Reference Figure 1 and Figure 2 The coil 200 may include a winding portion 210 embedded in the body 100 and leads 221 and 222 extending from the end of the winding portion 210 to the outer surface of the body 100.

[0056] The winding portion 210 may form at least one turn around the core 110. Leads 221 and 222 extend from both ends of the winding portion 210 toward the outer surface of the body 100 and may be connected to the external electrodes 300 and 400. Specifically, the coil 200 may include a winding portion 210 forming at least one turn in the body 100, a first lead 221 leading to a first surface 101, and a second lead 222 leading to a second surface 102 of the body 100.

[0057] The first lead-out portion 221 may be disposed between the first surface of the main body 100 and the first external electrode 300, and the second lead-out portion 222 may be disposed between the second surface of the main body 100 and the second external electrode 400. The first lead-out portion 221 may extend along the surfaces of the recesses R1 and R2 formed in the first surface 101 and the third surface 103 of the main body 100, and the second lead-out portion 222 may extend along the surfaces of the recesses R1 and R2 formed in the second surface 102 and the third surface 103 of the main body 100.

[0058] Reference Figure 2 and Figure 5 In this example embodiment, the leads 221 and 222 may be disposed in the region between a plurality of protrusions (e.g., 350a and 350b, 450a and 450b) formed on the inner surfaces of the bases 310 and 410 and / or the pads 330 and 430. Specifically, the first lead 221 may be configured to pass through the space between a pair of adjacent protrusions 350a and 350b arranged side by side in the third direction (W direction) among the plurality of protrusions 350 formed on the inner surfaces of the first base 310 and / or the first pad 330. Additionally, the second lead 222 may be configured to pass through the space between a pair of adjacent protrusions 450a and 450b arranged side by side in the third direction (W direction) among the plurality of protrusions 450 formed on the inner surfaces of the second base 410 and / or the second pad 430. Leads 221 and 222 may be configured to extend in a second direction (T direction) and / or a first direction (L direction) between a pair of protrusions (e.g., 350a and 350, 450a and 450b) arranged side by side in a third direction (W direction), thereby guiding the leads 221 and 222 to contact the inner surfaces of the outer electrodes 300 and 400.

[0059] Reference Figure 2 According to this example embodiment, the lead-out portions 221 and 222 can be led out in a region where the fourth surface 104 of the body 100 is closer to the region than the third surface 103, and the lead-out portions 221 and 222 can be disposed on the first surface 101 and the second surface 102 of the body 100. That is, assuming that the center line CL is parallel to the first direction (L direction) and passes through the center of the body 100, the lead-out portions 221 and 222 according to this example embodiment can be led out at a position higher than the center line CL, where the fourth surface 104 of the body 100 is closer to the third surface 103.

[0060] In this example embodiment, when leads 221 and 222 can be led out at a position above the center line CL, the bases 310 and 410 of the outer electrodes 300 and 400 can have a greater height, and the bases 310 and 410 can also have an increased surface area. In the case of the coil assembly 1000 having the above structure, when the coil assembly 1000 is mounted on the plate, the solder feet reinforced by the protrusions 350 and 450 can have a greater height, thereby increasing the stress relief effect. In addition, the contact area between leads 221 and 222 and the outer electrodes 300 and 400 can be increased, thus reducing the direct current (DC) resistance.

[0061] Reference Figure 2 At least a portion of each of the first lead-out portion 221 and the second lead-out portion 222 may be configured to extend from the first surface 101 and the second surface 102 of the body to the third surface 103 of the body 100, respectively, but this disclosure is not limited thereto. When it is necessary to reduce the thickness of the coil assembly 1000, the first lead-out portion 221 and the second lead-out portion 222 may be spaced apart from the third surface 103 of the body 100 and may be provided only on the first surface 101 and / or the second surface 102.

[0062] Reference Figures 3 to 5 Leads 221 and 222 can be formed at both ends of the roll-pressed coil 200 and can be flattened by rolling. That is, the thickness T of each of leads 221 and 222... L The diameter of the wire can be smaller than that of coil 200, and the width W of each of the leads 221 and 222 is... L The diameter of the wire in coil 200 can be larger than that of the lead wire in coil 200. For example, the diameter of the lead wire in coil 200 can be from 0.23 mm to 1.1 mm. In this case, the thickness T of each of the leads 221 and 222 is... L The width W of each of the leads 221 and 222 can be 0.15mm. L The diameter can range from 0.28 mm to 4.4 mm, but this disclosure is not limited thereto.

[0063] As described above, when the leads 221 and 222 have a surface contact structure with the external electrodes 300 and 400, the contact area between the leads 221 and 222 and the external electrodes 300 and 400 can be increased, thereby improving the bonding reliability and improving the DC resistance characteristics.

[0064] The coil 200 according to this example embodiment may correspond to an air-core coil and may be a wound coil, but this disclosure is not limited thereto. The area of ​​the coil 200, except for the leads 221 and 222 connected to the external electrodes 300 and 400, may be coated with an insulating material. Therefore, the surface of each turn of the winding portion 210 may be coated with an insulating material, so that the insulating properties are maintained even after winding.

[0065] Specifically, the winding portion 210 can be formed by winding a metal wire having a surface coated with an insulating material into a spiral shape. The metal wire can be copper wire, but this disclosure is not limited thereto.

[0066] The coil assembly 1000 according to this example embodiment shows a case where the winding portion 210 is formed using round wire, but this disclosure is not limited thereto. When the winding portion 210 is formed using metal wire in the form of flat wire, each turn of the winding portion 210 may have a quadrilateral cross section.

[0067] The coil 200 according to this example embodiment may include a conductive material comprising at least one selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), chromium (Cr), molybdenum (Mo), and alloys thereof, but this disclosure is not limited thereto.

[0068] Reference Figure 1 and Figure 2 According to this example embodiment, the coil assembly 1000 may include external electrodes 300 and 400 disposed on (e.g., embedded in) a body 100, which are connected to a coil 200. Additionally, in this example embodiment, the external electrodes 300 and 400 may include an inner surface facing the body 100 and an outer surface opposite to the inner surface. Protrusions 350 and 450 projecting toward the body 100 may be located in the inner surfaces of the external electrodes 300 and 400, and the outer surfaces of the external electrodes 300 and 400 (e.g., portions of the outer surfaces of the external electrodes 300 and 400 opposite to the protrusions 350 and 450) may have a flat shape. This may be because the external electrodes 300 and 400 may include a first metal layer ML1 and a second metal layer ML2 disposed on the first metal layer, wherein the protrusions 350 and 450 may be formed by the first metal layer ML1 having a protruding inner surface and a recessed outer surface, and the second metal layer ML2 filling the recessed area formed by the outer surface of the first metal layer ML1. Therefore, in the coil assembly 1000 of this example embodiment, the protrusions 350 and 450 are not visible on the outer surfaces of the outer electrodes 300 and 400. As a result, despite the formation of the protrusions 350 and 450, the appearance of the coil assembly 1000 does not differ significantly.

[0069] When the coil assembly 1000 according to this example embodiment is mounted on a circuit board or the like, the external electrodes 300 and 400 can electrically connect the coil assembly 1000 and the circuit board to each other. For example, the first external electrode 300 and the second external electrode 400, which are spaced apart from each other and provided on the third surface 103 of the body 100, can be electrically connected to the connection portion of the circuit board.

[0070] Specifically, the first external electrode 300 may be disposed on the first surface 101 of the main body 100 to contact the first lead-out portion 221 extending to the first surface 101 of the main body 100, and the second external electrode 400 may be disposed on the second surface 102 of the main body 100 to contact the second lead-out portion 222 extending to the second surface 102 of the main body 100.

[0071] Reference Figure 1 and Figure 2 According to this example embodiment, the external electrodes 300 and 400 may include bases 310 and 410, insertion portions 320 and 420, pad portions 330 and 430, and protrusions 350 and 450. Specifically, the first external electrode 300 may include a first base 310 disposed on a first surface 101 of the body 100, a first insertion portion 320 bent from the first base 310 and having at least a portion disposed in the body 100, and a first pad portion 330 bent from the first base 310 and extending to a third surface 103 of the body 100. The second external electrode 400 may include a second base 410 disposed on a second surface 102 of the body 100, a second insertion portion 420 bent from the second base 410 and having at least a portion disposed in the body 100, and a second pad portion 430 bent from the second base 410 and extending to the third surface 103 of the body 100. Additionally, protrusions 350 and 450 may be provided on at least one of the bases 310 and 410 and the pads 330 and 430.

[0072] Here, the bases 310 and 410, the insertion portions 320 and 420, the pad portions 330 and 430, and the protrusions 350 and 450 may be integrally formed. For ease of description, the outer electrodes 300 and 400 may be divided into multiple regions, and these multiple regions may be defined as the bases 310 and 410, the insertion portions 320 and 420, the pad portions 330 and 430, and the protrusions 350 and 450.

[0073] Reference Figure 1 and Figure 2 The first base 310 of the first external electrode 300 may be disposed on the first surface 101 of the main body 100, and more specifically, in the first recess R1 formed in the first surface 101. Additionally, the second base 410 of the second external electrode 400 may be disposed on the second surface 102 of the main body 100, and more specifically, in the second recess R2 formed in the second surface 102.

[0074] Bases 310 and 410 may be configured to contact leads 221 and 222 extending to the outer surface of the body 100, and at least one protrusion 350 may be provided on the first base 310, and at least one protrusion 450 may be provided on the second base 410. Specifically, protrusions 350 and 450 protruding toward the body 100 may be provided on the inner surfaces of bases 310 and 410, and the outer surfaces of bases 310 and 410 may have a flat shape.

[0075] Lead-out portions 221 and 222 may be disposed between the base portions 310 and 410 and the main body 100. Specifically, the first lead-out portion 221 may be disposed between the first base portion 310 and the first surface 101 of the main body 100, and the second lead-out portion 222 may be disposed between the second base portion 410 and the second surface 102 of the main body 100.

[0076] Reference Figure 2 and Figure 3 The thickness T of each of the leads 221 and 222 L The thickness T of the area protruding in the first direction (L direction) of the protrusions 350 and 450 formed on the inner surfaces of the bases 310 and 410 may be less than or equal to the thickness T. P With this structure, when leads 221 and 222 are positioned between a pair of protrusions (e.g., 350a and 350, 450a and 450b) formed on the inner surfaces of bases 310 and 410, leads 221 and 222 can be stably positioned within the space formed by the body 100 and the protrusions 350 and 450. Furthermore, leads 221 and 222 can be slightly spaced apart from the body 100, and a pair of adjacent protrusions (e.g., 350a and 350b, 450a and 450b) formed on the inner surfaces of bases 310 and 410 can be positioned to contact the body 100, thereby preventing movement or twisting of the outer electrodes 300 and 400.

[0077] Reference Figure 1 and Figure 2 According to this example embodiment, the external electrodes 300 and 400 may include insertion portions 320 and 420 bent from the bases 310 and 410, the insertion portions 320 and 420 having at least a portion disposed within the body 100. At least a portion of the insertion portions 320 and 420 may be inserted into the body 100 and may contact the leads 221 and 222. The insertion portions 320 and 420 may be used to secure the external electrodes 300 and 400 to the body 100 and may include anchor portions 321 and 421 at their inner ends.

[0078] Anchor portions 321 and 421 can perform an anchoring function within the body 100 to further enhance the bonding force between the external electrodes 300 and 400 and the body 100. Anchor portions 321 and 421 may have a shape that protrudes in a third direction W from the inner ends of the insertion portions 320 and 420, but this disclosure is not limited thereto. Anchor portions 321 and 421 may have various protruding directions or protruding shapes. Furthermore, anchor portions 321 and 421 may be formed on both sides of the inner ends of the insertion portions 320 and 420, or may be formed only on one side of the inner ends of the insertion portions 320 and 420.

[0079] Reference Figure 1 and Figure 2 The pads 330 and 430 are bendable from the bases 310 and 410 and extend to the third surface 103 of the body 100. The pads 330 and 430 extend in a first direction (L direction) and are disposed in recesses R1 and R2 formed in the third surface 103 of the body 100. Specifically, the first pad 330 is bendable from the first base 310 in the first direction (L direction) and disposed in the first recess R1 formed in the third surface 103 of the body 100, and the second pad 430 is bendable from the second base 410 in the first direction (L direction) and disposed in the second recess R2 formed in the third surface 103 of the body 100.

[0080] When the coil assembly 1000 according to this example embodiment is mounted on a circuit board, pads 330 and 430 can be connected to the connection portion of the circuit board. For example, bonding members such as solder can be provided between the pads 330 and 430 and the connection portion of the circuit board, so that the coil assembly 1000 and the circuit board can be electrically connected to each other.

[0081] When the coil assembly 1000 is mounted on the board, the bonding strength between the coil assembly 1000 and the board can be enhanced when the solder extends to a portion of the bases 310 and 410 to form solder feet, compared to the case where the pads 330 and 430 are connected to the board by solder. In this case, in the coil assembly 1000 according to some example embodiments of the present disclosure, in addition to the solder feet formed by solder, a second metal layer ML2 can flow downward from the protrusions 350 and 450 formed on the bases 310 and 410 during the reflow soldering process, thereby further enhancing the solder feet.

[0082] Reference Figures 1 to 5According to a first exemplary embodiment of the present disclosure, the coil assembly 1000 may include at least one protrusion 350 and at least one protrusion 450 projecting toward the body 100 from the inner surfaces of the bases 310 and 410 and / or the pads 330 and 430, respectively. The protrusions 350 and 450 according to this exemplary embodiment may include a semi-circular cross-section. Here, a semi-circular cross-section may refer not only to a cross-section having a precisely semi-circular shape, but also to a cross-section having an arcuate shape such as an ellipse.

[0083] Reference Figures 3 to 5 The external electrodes 300 and 400 may include a first metal layer ML1 disposed on the body 100 and a second metal layer ML2 disposed on the first metal layer ML1, and the protrusions 350 and 450 included in the external electrodes 300 and 400 may include a first metal layer ML1 protruding toward the body 100 and a second metal layer ML2 filling a recessed area formed in the outer surface of the first metal layer ML1. Here, the second metal layer ML2 may include Sn.

[0084] The second metal layer ML2, which fills the recessed area formed in the outer surface of the first metal layer ML1, enhances the solder feet F formed by the reflow soldering process when the coil assembly 1000 is mounted on the board, thereby strengthening the bond between the board and the coil assembly 1000. (Refer to the following...) Figures 19 to 23 Describe the form and effect of the enhanced solder joint F.

[0085] Reference Figures 2 to 5 According to a first exemplary embodiment of the coil assembly 1000 of this disclosure, the outer electrodes 300 and 400 may include bases 310 and 410 and pads 330 and 430. A plurality of protrusions 350 and 450 may be provided on the bases 310 and 410. Additionally, a plurality of protrusions 350 and 450 may be provided on the pads 330 and 430. In some embodiments, the outer electrodes 300 and 400 may include a plurality of protrusions 350 and 450 provided on both the bases 310 and 410 and the pads 330 and 430. Preferably, an even number of protrusions 350 and 450 may be formed. (Refer to...) Figure 6 For example, in the first external electrode 300, the first lead-out portion 221 may be disposed between a pair of adjacent protrusions 350a and 350b arranged side by side along a third direction (W direction). Similarly, in the second external electrode 400, the second lead-out portion 222 may be disposed between a pair of adjacent protrusions 450a and 450b arranged side by side along a third direction (W direction). That is, a pair of adjacent protrusions 350a and 350b and a pair of adjacent protrusions 450a and 450b may be arranged side by side in a direction perpendicular to the direction in which the leads-out portions 221 and 222 extend on the body 100.

[0086] Reference Figure 3 and Figure 4 The thickness T of each of the leads 221 and 222 L The thickness T of each of the protruding areas of protrusions 350 and 450 may be less than or equal to the thickness of the protrusion. P When the thickness T of each of the leads 221 and 222 is... L The thickness T is greater than that of each of the protrusions 350 and 450. P At this time, protrusions 350 and 450 may be spaced apart from the body 100, therefore, movement or twisting of the outer electrodes 300 and 400 may occur. In this example embodiment, the thickness T of each of the protruding regions of protrusions 350 and 450 is... P It can be formed to have a thickness T greater than or equal to that of each of the leads 221 and 222. L This allows the external electrodes 300 and 400 to be stably fixed to the main body 100.

[0087] Here, regarding the optical microscope or SEM image of the LT section obtained by cutting the coil assembly 1000 at the central portion on the third-party W, the thickness T of each of the leads 221 and 222... L This can refer to the arithmetic mean of at least three dimensions of a plurality of line segments, wherein the two outermost boundary lines of each of the leads 221 and 222 shown in the image are connected to each other in a first direction (L direction) to be parallel to the first direction (L direction), and the plurality of line segments are spaced apart from each other in a second direction (T direction). Here, the plurality of line segments parallel to the first direction (L direction) may be equidistant from each other in the second direction (T direction), but this disclosure is not limited thereto.

[0088] In addition, the thickness T of each of the protrusions 350 and 450 P It can be defined as the distance from the inner surface of each of the bases 310 and 410 (i.e., the flat surface of the first metal layer ML1 in contact with the leads 221 and 222) to the point where each of the protrusions 350 and 450 protrudes most toward the body 100. Here, the thickness T of each of the protrusions 350 and 450 is... P The dimension of a line segment that connects the extension line of the flat surface of the first metal layer ML1 in contact with the leads 221 and 222 to each of the protrusions 350 and 450 that protrude most toward the body 100 to each other in a direction parallel to the first direction (L direction).

[0089] Although based on such Figure 3 The protrusions 350 and 450 formed on the bases 310 and 410 shown describe a measurement method, but this measurement method can be similarly applied to, for example... Figure 4 The protrusions 350 and 450 formed on the pads 330 and 430 are shown.

[0090] Reference Figure 1 and Figure 5 For example, a pair of adjacent protrusions 350a and 350b may be formed on the inner surface of the first base 310 and may be arranged side by side in the third direction (W direction), and the minimum distance W between a pair of adjacent protrusions 350a and 350b is... G It can be greater than the maximum line width W of the first lead-out section 221. L .

[0091] Here, regarding the optical microscope or SEM image of the LW section (the LW section is perpendicular to the second direction (T direction)) passing through the center of each of a pair of adjacent protrusions 350a and 350b, the maximum linewidth W of the first lead-out 221 is... L This can refer to the maximum value of a plurality of line segments, wherein the two outermost boundary lines of each of the leads 221 and 222 shown in the image, which are opposite each other in a third direction (W direction), are connected to each other to be parallel to the third direction (W direction), and the plurality of line segments are spaced apart from each other in a first direction (L direction). The plurality of line segments parallel to the third direction (W direction) may be equidistant from each other in the first direction (L direction), but this disclosure is not limited thereto.

[0092] Additionally, the minimum distance W between a pair of adjacent protrusions 350a and 350b G It can refer to the minimum value among multiple line segments, each line segment extending parallel to a third direction (W direction) between two extension lines that are parallel to the first direction (L direction) and pass through the starting points of a pair of adjacent protrusions 350a and 350b.

[0093] The heights of a pair of adjacent protrusions 350a and 350b may be substantially the same. Here, "substantially the same" can mean identical, taking into account factors such as process errors, positional deviations, or measurement inaccuracies that may occur during manufacturing. Furthermore, the height of each of a pair of adjacent protrusions 350a and 350b can be defined as being equal to the aforementioned thickness T of each of the protrusion regions. P The same applies, and the thickness T can be used for each of the protruding regions of a pair of adjacent protrusions 350a and 350b as described above. P The measurement method described is similar to the method used for measurement.

[0094] A pair of adjacent protrusions 350a and 350b may have substantially the same height T. P This prevents the external electrodes 300 and 400 from moving or twisting, and stably fixes the external electrodes 300 and 400 to the main body 100.

[0095] Additionally, although not shown, a pair of adjacent protrusions 450a and 450b of the second external electrode 400 may also have the same features as the pair of adjacent protrusions 350a and 350b of the first external electrode 300 described above.

[0096] Reference Figure 5 The width W of each of the protrusions 350 and 450 according to this example embodiment P It can be twice or more the average thickness of each of the outer electrodes 300 and 400. Furthermore, the width W of each of the outer electrodes 300 and 400 in the third direction (W direction)... E The width W of each of the protrusions 350 and 450 can be P Twice or more. For example, the width W of each of protrusions 350 and 450. P It can be from 0.15mm to 0.65mm. Additionally, the width W of each of the outer electrodes 300 and 400 in the third direction (W direction) is... E It can be 2mm to 5mm. However, the above values ​​are exemplary values, and this disclosure is not limited thereto.

[0097] Reference Figure 1 According to this example embodiment, the external electrodes 300 and 400 may further include openings O in at least a portion of the curved regions formed between the bases 310 and 410 and the insertion portions 320 and 420, and between the bases 310 and 410 and the pad portions 330 and 430.

[0098] The opening O can penetrate the outer electrodes 300 and 400, and can reduce the load on the outer electrodes 300 and 400 during the bending process from a flat shape, thereby preventing damage to the outer electrodes 300 and 400. When the outer electrodes 300 and 400 have sufficient rigidity to withstand the load generated during the bending process, the opening O can be omitted.

[0099] The external electrodes 300 and 400 according to this example embodiment may comprise a conductive material selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), chromium (Cr), molybdenum (Mo), and alloys thereof, and may be formed in a multilayer form, but this disclosure is not limited thereto. Furthermore, the external electrodes 300 and 400 may be fixed to the frame by a roll forming process, but this disclosure is not limited thereto.

[0100] Although not shown, the coil assembly 1000 according to this example embodiment may also include an insulating layer covering the surface of the body 100.

[0101] The insulating layer can be formed by methods such as printing, vapor deposition, spraying or film lamination, but this disclosure is not limited thereto.

[0102] The insulating layer may include thermoplastic resins (such as polystyrene resins, vinyl acetate resins, polyester resins, polyethylene resins, polypropylene resins, polyamide resins, rubber resins, acrylic resins, parylene, etc.), thermosetting resins (such as phenolic resins, epoxy resins, polyurethane resins, melamine resins, alkyd resins, etc.), photosensitive resins, SiO2, etc. x or SiN x The insulating layer may also include insulating fillers such as inorganic fillers, but this disclosure is not limited thereto.

[0103] Figure 6 This is a schematic diagram illustrating the process of forming a coil 200 and external electrodes 300 and 400 of a coil assembly according to a second exemplary embodiment of the present disclosure. Figure 7 yes Figure 1 An exploded perspective view, showing the form of the outer electrode before bending.

[0104] Reference Figure 6 In the coil assembly 1000 according to this example embodiment, outer electrodes 300 and 400 may be formed on the frame first, and coil 200 may be disposed on the outer electrodes 300 and 400. First lead-out portion 221 and second lead-out portion 222 may be disposed between a pair of adjacent protrusions 350a and 350b and a pair of adjacent protrusions 450a and 450b, respectively.

[0105] Anchor portions 321 and 421, opening O, and protrusions 350 and 450 can be pre-formed on the outer electrodes 300 and 400 using frames before they are joined to the coil 200. Leads 221 and 222 at both ends of the coil 200 can be joined to the outer electrodes 300 and 400 after the insulation layer of the coil 200 is removed and rolled. An additional covering layer can be formed during the joining process by impregnation, welding, etc., but this disclosure is not limited thereto. The coil 200 and the outer electrodes 300 and 400 can be repositioned in the direction of embedding in the body 100.

[0106] Reference Figure 7 ,based on Figure 6 The structure in which the coil 200 formed in the body is combined with the external electrodes 300 and 400 can be formed by pressing and solidifying the upper region 100a and the lower region 100b of the body 100 in the vertical direction, respectively. A portion of the lower region 100b of the body 100 can be filled in the hollow core of the coil 200 in the vertical direction to form the core 110, but this disclosure is not limited thereto.

[0107] As described above, after the main body 100 is formed, the lead-out portions 221 and 222 and the external electrodes 300 and 400 can be respectively installed in the recesses R1 and R2 by bending the lead-out portions 221 and 222 and the external electrodes 300 and 400 twice along the shape of the main body 100.

[0108] Variations of the first example embodiment Figures 8 to 11 It is shown Figure 5 The diagram shows the variations in the cross-sectional shape of the protrusions 350 and 450.

[0109] Will Figures 8 to 11 and Figure 5 By comparison, the coil assemblies 1000a, 1000b, 1000c, and 1000d according to this variant may have a pair of adjacent protrusions 350a and 350b with different LW cross-sectional shapes. Therefore, in describing this variant, only the cross-sectional shapes of a pair of adjacent protrusions 350a and 350b that differ from the cross-sectional shapes of a pair of adjacent protrusions 350a and 350b in the first exemplary embodiment of this disclosure will be described, and the description of the first exemplary embodiment of this disclosure can be applied to the remaining components in the same manner.

[0110] Reference Figure 8 According to the first variant, a pair of adjacent protrusions 350a and 350b of the coil assembly 1000a may include an arched cross-section. That is, according to this variant, a pair of adjacent protrusions 350a and 350b may have a cylindrical shape with a rounded upper surface. However, the shape is not limited to a cylindrical shape, and the pair of adjacent protrusions 350a and 350b may also have a prism shape (with planar side surfaces). In this variant, when the first lead-out portion 221 is thick, the height T of each of the pair of adjacent protrusions 350a and 350b can be increased. P Without increasing the area of ​​each of the pair of adjacent protrusions 350a and 350b.

[0111] Reference Figure 9According to the second variant, a pair of adjacent protrusions 350a and 350b of the coil assembly 1000b may include a tapered cross-section (e.g., a trapezoidal cross-section). That is, according to this variant, a pair of adjacent protrusions 350a and 350b may have a frustum shape, which has a cross-sectional area that gradually increases from its upper surface to its lower surface. However, the shape is not limited to a frustum shape, and a pair of adjacent protrusions 350a and 350b may also have a truncated pyramid shape (having planar side surfaces). In this variant, a pair of adjacent protrusions 350a and 350b may have inclined side surfaces. When the first lead-out 221 is provided, even if the alignment is slightly misaligned, the first lead-out 221 can be installed in the correct position along the inclined side surfaces.

[0112] Reference Figure 10 According to the third variant of the coil assembly 1000c, a pair of adjacent protrusions 350a and 350b may include a triangular cross-section. That is, according to this variant, a pair of adjacent protrusions 350a and 350b may have a conical shape. However, the shape is not limited to a conical shape, and may also have a polygonal pyramidal shape (with planar side surfaces). In this variant, a pair of adjacent protrusions 350a and 350b may have inclined side surfaces. When the first lead-out 221 is provided, even if the alignment is slightly misaligned, the first lead-out 221 can be installed in the correct position along the inclined side surfaces. A large open space may exist between a pair of adjacent protrusions 350a and 350b, making it easy to provide the first lead-out 221.

[0113] Reference Figure 11 According to the fourth variant, a pair of adjacent protrusions 350a and 350b of the coil assembly 1000d may include a quadrilateral cross-section. That is, the pair of adjacent protrusions 350a and 350b according to this variant may have a cylindrical shape. However, the shape is not limited to a cylindrical shape, and may also have a polygonal prism shape (with planar side surfaces). In this variant, the contact area between the pair of adjacent protrusions 350a and 350b and the body 100 can be increased, thereby improving the effect of the pair of adjacent protrusions 350a and 350b in supporting the first external electrode 300, and increasing the amount of the second metal layer ML2 filling the pair of adjacent protrusions 350a and 350b. Therefore, the effect of enhancing the solder joints formed by the soldering process when the coil assembly 1000d is mounted on the plate can also be improved.

[0114] Second example embodiment, third example embodiment and fourth example embodiment Figure 12 This is a diagram showing the leads 221 and 222 and the external electrodes 300 and 400 of a coil assembly 2000 according to a second exemplary embodiment of the present disclosure. Figure 13This is a diagram showing the leads 221 and 222 and the external electrodes 300 and 400 of the coil assembly 3000 according to a third exemplary embodiment of the present disclosure. Figure 14 This is a diagram showing the leads 221 and 222 and the external electrodes 300 and 400 of the coil assembly 4000 according to a fourth exemplary embodiment of the present disclosure. Figures 12 to 14 In this diagram, the main body 100 and the winding portion 210 are omitted to clearly show the detailed shapes of the lead-out portions 221 and 222 and the external electrodes 300 and 400.

[0115] Will Figures 12 to 14 and Figure 1 A comparison reveals differences in the number and arrangement of protrusions 350 and 450. Therefore, in the description of this exemplary embodiment, only the number and arrangement of protrusions 350 and 450 that differ from those in the first exemplary embodiment of this disclosure will be described, and the description of the first exemplary embodiment of this disclosure can be applied in the same manner to the remaining components.

[0116] Reference Figure 12 In the coil assembly 2000 according to a second exemplary embodiment of the present disclosure, the number of protrusions 350 and 450 provided on each of the bases 310 and 410 may be three or more. For example, in this exemplary embodiment, three pairs (i.e., six) of protrusions 350 and three pairs (i.e., six) of protrusions 450 may be provided on the bases 310 and 410 respectively, and the leads 221 and 222 may be configured to pass through the space between adjacent protrusions (e.g., 350a and 350b, and 450a and 450b) in a second direction (T direction).

[0117] In this example embodiment, the guiding effect of leads 221 and 222 can be further improved, and the supporting effect of external electrodes 300 and 400 can be further enhanced. Furthermore, the solder joint reinforcement effect can be further improved by filling each of the six protrusions 350 and 450 with a second metal layer ML2 (e.g., Sn). Additionally, the six protrusions 350 and 450 can be arranged in three layers in the second direction (T direction), thereby obtaining a corresponding solder joint reinforcement effect depending on the height of the solder joints formed when mounted on the board.

[0118] In this example embodiment, the number of protrusions 350 and 450 provided on the bases 310 and 410 is exemplary and not limited thereto, and can be increased or decreased as needed. Preferably, the number of protrusions 350 and 450 can be increased or decreased in even numbers.

[0119] Reference Figure 13In the coil assembly 3000 according to the third exemplary embodiment of the present disclosure, a pair of protrusions 350a and 350b and a pair of protrusions 450a and 450b may be respectively provided on the first base 310 and the second base 410, and the protrusions on the pads 330 and 430 may be omitted.

[0120] The height of a pair of protrusions (e.g., 350a and 350b, 450a and 450b) disposed on bases 310 and 410 in this example embodiment can be adjusted. In this example embodiment, the pair of protrusions (e.g., 350a and 350b, 450a and 450b) may be formed in an area close to insert portions 320 and 420, but this disclosure is not limited thereto. Taking into account the height of solder feet formed by solder when mounted on a board, the pair of protrusions (e.g., 350a and 350b, 450a and 450b) may be formed in an area closer to pad portions 330 and 430.

[0121] Reference Figure 14 In the coil assembly 4000 according to the fourth exemplary embodiment of the present disclosure, a pair of protrusions 350a and 350b and a pair of protrusions 450a and 450b may be respectively provided on the first pad portion 330 and the second pad portion 430, and the protrusions on the base portions 310 and 410 may be omitted.

[0122] The protrusions (e.g., 350a and 350b, 450a and 450b) provided on the pads 330 and 430 according to this example embodiment can enhance the bonding force between the pads 330 and 430 and the board by bonding a second metal layer ML2 (e.g., Sn) filled in the protrusions (e.g., 350a and 350b, 450a and 450b) with solder when the coil assembly 4000 is mounted on the board.

[0123] Fifth Example Embodiment, Sixth Example Embodiment, and Seventh Example Embodiment Figure 15 This is a schematic perspective view of a coil assembly 5000 according to a fifth exemplary embodiment of the present disclosure. Figure 16 It is along Figure 15 The cross-sectional view taken from line III-III'. Figure 15 In the middle, the main body 100 is shown in a transparent manner to clearly show the arrangement relationship between the elements.

[0124] Will Figure 15 and Figure 16 respectively with Figure 1 and Figure 2A comparison reveals differences in the positions of each of the leads 221 and 222 extending into the body 100, the positions of each of the inserts 320 and 420 inserting into the body 100, and the lengths of each of the bases 310 and 410 in the second direction (T direction). Therefore, in describing this exemplary embodiment, only the positions of each of the leads 221 and 222 extending into the body 100, the positions of each of the inserts 320 and 420 inserting into the body 100, and the lengths of each of the bases 310 and 410 in the second direction (T direction) that differ from the first exemplary embodiment of this disclosure will be described, and the description of the first exemplary embodiment of this disclosure can be applied in the same manner to the remaining components.

[0125] Reference Figure 15 and Figure 16 According to this example embodiment, the lead-out portions 221 and 222 can extend into regions on the first surface 101 and second surface 102 of the body 100, where the third surface 103 of the body 100 is closer to the region than the fourth surface 104 of the body 100. Optionally, the lead-out portions 221 and 222 can extend into the central region in the second direction (T direction), on the first surface 101 and second surface 102 of the body 100. That is, assuming a centerline CL that passes through the center of the body 100 and is parallel to the first direction (L direction), according to this example embodiment, the lead-out portions 221 and 222 can extend into the first surface 101 and second surface 102 of the body 100 at positions equal to or lower than the centerline CL.

[0126] Furthermore, as the lead-out height of each of the lead-out portions 221 and 222 of the coil assembly 5000 according to this example embodiment decreases, the height at which each of the insertion portions 320 and 420 of the external electrodes 300 and 400 is inserted into the body 100 can be reduced, and the length of each of the base portions 310 and 410 of the external electrodes 300 and 400 in the second direction (T direction) can be reduced.

[0127] As in this example embodiment, when the leads 221 and 222 are led out at a height lower than or equal to the centerline CL, and thus the height of each of the inserts 320 and 420 is reduced and the length of each of the bases 310 and 410 in the second direction (T direction) is reduced, the overall center of gravity of the coil assembly 5000 can be lowered. Therefore, when mounted on a board, vibration resistance can be improved, thereby further enhancing the vibration resistance effect produced by the protrusions 350 and 450 included in the outer electrodes 300 and 400.

[0128] Figure 17This is a diagram showing the leads 221 and 222 and the external electrodes 300 and 400 of the coil assembly 6000 according to a sixth exemplary embodiment of the present disclosure. Figure 18 This is a diagram showing the leads 221 and 222 and the external electrodes 300 and 400 of a coil assembly 7000 according to a seventh exemplary embodiment of the present disclosure. Figure 17 and Figure 18 In this diagram, the main body 100 and the winding portion 210 are omitted in order to clearly show the detailed shapes of the lead-out portions 221 and 222 and the external electrodes 300 and 400.

[0129] Will Figure 17 and Figure 18 and Figure 15 A comparison reveals differences in the arrangement of protrusions 350 and 450. Therefore, in describing this exemplary embodiment, only the arrangement of protrusions 350 and 450 that differs from that of the fifth exemplary embodiment of this disclosure will be described, and the description of the fifth exemplary embodiment of this disclosure can be applied in the same manner to the remaining components.

[0130] Reference Figure 17 In the coil assembly 6000 according to the sixth exemplary embodiment of the present disclosure, a pair of protrusions 350a and 350b and a pair of protrusions 450a and 450b may be respectively provided on the first base 310 and the second base 410, and the protrusions on the pads 330 and 430 may be omitted.

[0131] Similar to the coil assembly 5000 according to the fifth exemplary embodiment, the coil assembly 6000 according to this exemplary embodiment may have a low center of gravity. Specifically, since the leads 221 and 222 are led out at a low height, the positions of the insertion portions 320 and 420 can also be lowered, and the lengths of the bases 310 and 410 can be reduced. Therefore, the area of ​​each of the bases 310 and 410 can be reduced, allowing a pair of protrusions 350a and 350b and a pair of protrusions 450a and 450b to be respectively provided on the first base 310 and the second base 410, but this disclosure is not limited thereto. The number of protrusions 350 and 450 can be increased when the protrusions 350 and 450 are formed to have a small diameter or width.

[0132] Although not shown, the leads 221 and 222 may be configured not to extend into the pads 330 and 430, so that the body 100 and the pads 330 and 430 can be in close contact with each other, thereby reducing the size of the assembly. Alternatively, the body 100 may be extended to the space between the pads 330 and 430 and the body 100 by omitting the leads 221 and 222 and the protrusions 350 and 450, thereby increasing the effective volume.

[0133] Reference Figure 18In the coil assembly 7000 according to the seventh exemplary embodiment of the present disclosure, a pair of protrusions 350a and 350b and a pair of protrusions 450a and 450b may be respectively provided on the first pad portion 330 and the second pad portion 430, and the protrusions on the base portions 310 and 410 may be omitted.

[0134] Similar to the coil assembly 5000 according to the fifth exemplary embodiment, the coil assembly 7000 according to this exemplary embodiment may have a low center of gravity. Specifically, since the leads 221 and 222 are led out at a low height, the positions of the insertion portions 320 and 420 can also be lowered, and the lengths of the bases 310 and 410 can be reduced. In this exemplary embodiment, the protrusions 350 and 450 on the bases 310 and 410 can be omitted, thereby further lowering the center of gravity of the coil assembly 7000 and improving its vibration resistance when mounted on a board. In addition, since the protrusions 350 and 450 on the bases 310 and 410 are omitted, the lengths of the bases 310 and 410 in the second direction (T direction) can be reduced, thereby further lowering the center of gravity.

[0135] The protrusions (e.g., 350a and 350b, 450a and 450b) provided on the pads 330 and 430 according to this example embodiment can enhance the bonding force between the pads 330 and 430 and the board by bonding a second metal layer ML2 (e.g., Sn) filled in the protrusions (e.g., 350a and 350b, 450a and 450b) with solder when the coil assembly 7000 is mounted on the board.

[0136] Changes in solder pad shape and stress when coil assembly is mounted on board Figure 19 It is shown that from Figure 1 A schematic diagram showing the form of solder feet F when the coil assembly 1000', with protrusions 350 and 450 omitted, is mounted on the plate 10. Figure 20 It is shown in the Figure 1 A schematic diagram of the form of reinforced solder feet F when the coil assembly 1000 is mounted on the board 10.

[0137] Reference Figure 19 When the coil assembly 1000' is mounted on the board 10, solder can be applied to the outer electrodes 300 and 400 and the connecting portion 11 via a reflow soldering process, thus allowing the coil assembly 1000' and the board 10 to be electrically connected to each other. In this case, solder feet F provided to a portion of the side surfaces of the outer electrodes 300 and 400 can enhance the bonding strength.

[0138] Will Figure 20 and Figure 19In comparison, when the coil assembly 1000 according to the first exemplary embodiment of this disclosure is mounted on the plate 10, reinforced solder feet F' can be formed because the Sn component filling the protrusions 350 and 450 included in the outer electrodes 300 and 400 flows downward due to the reflow soldering process. The amount of solder feet F' to be reinforced or the radius of curvature of the inclined surfaces can be adjusted according to the diameter or formation location of each of the protrusions 350 and 450.

[0139] Figure 21 This is an experimental example showing the formation of solder feet F when a coil assembly excluding protrusions 350 and 450 is mounted on plate 10. Figure 22 This is an experimental example showing the formation of solder feet F' when a coil assembly including protrusions 350 and 450 is mounted on plate 10.

[0140] The solder thickness of the sample used was 50 μm, the thickness of the external electrodes 300 and 400 was 0.2 mm, and the radius of the protrusions 350 and 450 was 0.27 mm. The position of the protrusions was... Figure 15 The same as in the fifth embodiment.

[0141] Reference Figure 21 When the coil assembly of the outer electrodes 300 and 400, excluding the protrusions 350 and 450, is mounted on the plate 10, the cross section of the weld foot F formed by the welding process has a radius of curvature (R) of 2.30 mm, i.e., R2.30.

[0142] Will Figure 22 and Figure 21 In comparison, when the coil assembly in which the outer electrodes 300 and 400 include protrusions 350 and 450 is mounted on the plate 10, the cross section of the solder foot F' reinforced by the protrusions 350 and 450 has a radius of curvature (R) of 6.90 mm, i.e., R6.90.

[0143] When protrusions 350 and 450 are included in the outer electrodes 300 and 400 as described above, it is confirmed that the radius of curvature of the formed solder foot F' increases to three times, and the amount of formed solder foot F' also increases.

[0144] Figure 23 This is an example illustrating simulation results based on stress variations according to weld bead formation and weld bead reinforcement. The protrusion is set as follows: Figure 1 The positioning is as described in the first example embodiment. When a stress of 10N is applied on a single axis, the change in the radius of curvature of the weld foot and the change in stress applied to the outer electrode are simulated based on the change in the radius of the protrusion.

[0145] [Table 1]

[0146] Refer to Table 1 and Figure 23 , the stress relief effect was confirmed by simulation based on the relative value of the maximum stress applied to the outer electrode in the case (a) where only the lower surface of the fixed outer electrode was present. In the case (b) where the solder feet were formed only by solder (the radius of curvature of the solder feet was C1) and there were no protrusions, a stress relief of -63.9% was measured. In cases (c) to (f), four protrusions were formed on each of the left outer electrode and the right outer electrode. As the radius of each protrusion increased, the volume of Sn in the protrusions of the solder feet that could be enhanced also increased. Therefore, the maximum height of the solder feet and the radius of curvature of the inclined surface increased (R1 < R2 < R3 < R4), and an improvement in the maximum stress relief effect was also observed.

[0147] Although some example embodiments have been shown and described above, it will be readily understood by those skilled in the art that modifications and variations can be made without departing from the scope of the present disclosure defined by the appended claims.

Claims

1. A coil assembly, comprising: The main body includes a first surface and a second surface that are opposite to each other in a first direction, and a third surface and a fourth surface that are opposite to each other in a second direction perpendicular to the first direction; The coil includes a winding portion embedded in the body and a lead-out portion extending from an end of the winding portion to an outer surface of the body in the first direction; as well as An external electrode is disposed on the main body, the external electrode having an inner surface facing the main body and an outer surface opposite to the inner surface. The external electrode includes a protrusion that extends toward the main body, and the lead-out portion contacts the inner surface of the external electrode.

2. The coil assembly as claimed in claim 1, wherein, The portion of the outer surface of the outer electrode opposite to the protrusion has a flat shape.

3. The coil assembly as claimed in claim 2, wherein, The external electrode includes a first metal layer disposed on the main body and a second metal layer disposed on the first metal layer, and The protrusion includes a first metal layer protruding toward the body and a second metal layer filling a recessed area formed in the outer surface of the first metal layer.

4. The coil assembly as claimed in claim 3, wherein, The second metal layer includes Sn.

5. The coil assembly as claimed in claim 1, wherein, The external electrode includes: a base disposed on the first surface and / or the second surface; an insertion portion bent from the base toward the interior of the body, the insertion portion having at least a portion disposed in the body; and a pad portion bent from the base to be disposed on a portion of the third surface of the body.

6. The coil assembly as claimed in claim 5, wherein, The protrusion is provided on at least one of the base and the pad.

7. The coil assembly of claim 6, wherein, The external electrode includes more than one protrusion, and the more than one protrusion is disposed on the base.

8. The coil assembly of claim 6, wherein, The external electrode includes more than one protrusion, and the more than one protrusion is disposed on the pad portion.

9. The coil assembly as claimed in claim 1, wherein, The external electrode includes more than one protrusion, and The lead-out portion is disposed between at least one pair of protrusions among the more than one protrusion.

10. The coil assembly of claim 9, wherein, One pair of the at least one pair of protrusions is arranged side by side in a third direction, the third direction being perpendicular to the first direction and the second direction, respectively. The minimum distance between the pair of protrusions is greater than the maximum line width of the lead-out portion in the third direction.

11. The coil assembly of claim 9, wherein, The height of one pair of protrusions in the at least one pair of protrusions is substantially the same.

12. The coil assembly of claim 1, wherein, The cross-section of the protrusion has a semi-circular shape, an arch shape, a trapezoidal shape, a triangular shape, or a quadrilateral shape.

13. The coil assembly of claim 1, wherein, The lead-out portion extends from the end of the winding portion along the first direction and is led out from the lead-out position on the first surface and / or the second surface, wherein the fourth surface is closer to the lead-out position than the third surface.

14. The coil assembly of claim 1, wherein, The lead-out portion extends from the end of the winding portion along the first direction and is led out from a lead-out position on the first surface and / or the second surface, wherein the third surface is closer to the lead-out position than the fourth surface, or the lead-out position is located in the central region of the first surface and / or the second surface in the second direction.

15. The coil assembly of claim 1, wherein, The coil includes multiple leads, including a first lead and a second lead. The first lead-out portion extends along the first surface and is disposed on the first surface. The second lead-out portion extends along the second surface and is disposed on the second surface, and At least a portion of each of the first lead-out portion and the second lead-out portion extends to and is disposed on the third surface.

16. A coil assembly, comprising: main body; A coil, embedded in the body, the coil including a lead-out portion; and An external electrode is disposed on the main body and connected to the lead-out portion. The external electrode includes multiple protrusions. The lead-out portion is disposed between the first and second protrusions that are adjacent to each other among the plurality of protrusions.

17. The coil assembly of claim 16, wherein, The first protrusion and the second protrusion are arranged adjacent to each other in a direction perpendicular to the direction in which the lead-out portion extends on the body.

18. The coil assembly of claim 16, wherein, The number of protrusions is even.

19. The coil assembly of claim 16, wherein, The thickness of the lead-out portion is less than or equal to the thickness of the protruding area of ​​the plurality of protrusions.

20. A coil assembly, comprising: The main body includes a first surface and a second surface that are opposite to each other in a first direction, and a third surface and a fourth surface that are opposite to each other in a second direction perpendicular to the first direction; The coil includes a winding portion embedded in the body and a lead-out portion extending from an end of the winding portion to an outer surface of the body along the first direction; as well as An external electrode is disposed on the body, and a portion of the lead-out portion is located between the external electrode and the first surface and / or the second surface of the body.

21. The coil assembly of claim 20, wherein, The body has a first recess in the region where the first surface and the third surface are connected to each other, and the body has a second recess in the region where the second surface and the third surface are connected to each other, and a portion of the lead-out portion is disposed in the first recess and / or the second recess.

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