Inductor, manufacturing method thereof and electronic device

Abstract

The application provides an inductor, a preparation method thereof and an electronic device. The inductor comprises a winding and a magnetic member at least partially covering the winding; the winding comprises a conductive body and a conductive layer arranged on the surface of the conductive layer. The application adopts the combination of the conductive body and the conductive layer to form the winding, and the winding is at least partially covered on the magnetic member, so that the gap between the winding and the magnetic body can be reduced when the inductor with the same volume is prepared, the DCR (direct current resistance) is reduced, and the current carrying capacity is improved.

Description

Technical Field

[0001] This invention belongs to the field of electronic technology, specifically relating to an inductor, its preparation method, and an electronic device. Background Technology

[0002] Inductors are one of the three major passive components in electronic circuits, primarily serving functions such as filtering, oscillation, delay, notch filtering, signal screening, noise filtering, current stabilization, and suppression of electromagnetic interference. With the rapid development of electronic technology, especially the widespread adoption of mobile consumer electronics, inductors are evolving towards miniaturization, thinning, higher frequency operation, higher current handling, higher efficiency, and lower EMI (electromagnetic interference). Current technologies for manufacturing inductors involve molding the winding and magnetic powder together in a mold cavity, but this molding process can easily cause the insulation layer on the coil surface to crack, and is affected by the pressure during molding. Alternatively, the magnetic material and coil can be fabricated separately and then assembled, but this requires ensuring the relative positions of the magnetic materials and between the magnetic materials and the winding.

[0003] Therefore, how to solve the above problems and improve the electromagnetic performance of inductors is a key area that urgently needs to be studied. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an inductor, its fabrication method, and an electronic device. The present invention employs a combination of a conductor and a conductive layer to form a winding, which at least partially covers a magnetic component. This allows for a reduction in the gap between the winding and the magnetic component when fabricating an inductor of the same volume, thus helping to reduce the DC resistance (DCR) and improve its current-carrying capacity.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides an inductor, the inductor including a winding and a magnetic element at least partially covering the winding; the winding includes a conductor and a conductive layer disposed on the surface of the conductive layer.

[0007] This invention employs a combination of a conductor and a conductive layer to form the winding. This allows for a reduction in the gap between the winding and the magnetic material when fabricating inductors of the same volume, thus helping to reduce current-carrying capacity (DCR) and improve current conductivity. Furthermore, by placing at least a portion of the winding within the magnetic component, and since the magnetic component and winding are molded separately, a higher density magnetic material can be fabricated to enhance electromagnetic performance.

[0008] Preferably, the magnetic component includes:

[0009] A first magnetic body has a groove on its first surface, and the winding is disposed in the groove, with the winding fitting against the inner wall of the groove.

[0010] A second magnetic body is stacked on the first surface of the first magnetic body and covers the winding.

[0011] In this invention, a conductor is placed in the groove of a first magnetic body, and then a conductive layer is used to fill the gap between the conductor and the magnetic body. Subsequently, a second magnetic body is covered on the winding. Since the magnetic body and the winding are molded separately, a magnetic body with a higher density can be prepared to improve electromagnetic performance.

[0012] Preferably, the conductor is further provided with conductive pins, which protrude from the side of the conductor away from the first magnetic body, extend toward the second magnetic body and penetrate the second magnetic body; wherein, the density of the first magnetic body is greater than the density of the second magnetic body, and the permeability of the first magnetic body is greater than the permeability of the second magnetic body.

[0013] Preferably, the materials of the conductor and the conductive layer each independently include metallic materials and / or carbon materials.

[0014] Preferably, the metallic material includes any one or a combination of at least two of Au, Pt, Pd, Ag, Cu, Al, Co, Cr, Zn, Ni, Ti, W, Fe, Sn, or In.

[0015] Preferably, the conductor is a conductive strip. For example, it could be a copper strip, which can be formed from copper through physical or chemical means.

[0016] It should be noted that the present invention does not specifically limit the thickness relationship between the conductor and the conductive layer in the groove, and the conductor and the conductive layer can have the same thickness or different thickness.

[0017] Preferably, the positional relationship between the conductive layer and the conductor includes at least one of the following:

[0018] The conductive layer is formed between the conductor and the inner wall of the groove, and covers the upper surface of the conductor. (In this case, the upper surface of the conductive layer may or may not be flush with the first surface of the first magnetic body.)

[0019] The conductive layer is formed between the conductor and the inner wall of the groove, and the upper surface of the conductive layer is flush with the upper surface of the conductor. (In this case, the upper surface of the winding may be flush with or not flush with the first surface of the first magnet.)

[0020] Preferably, the lower end face of the conductor is attached to the bottom wall of the groove, or the lower end face of the conductor and the bottom wall of the groove are separated by the conductive layer.

[0021] Preferably, the distance between the conductor and the sidewall of the groove is equal, or the distance gradually increases along the thickness direction of the conductor. For example, the cross-section of the groove is an inverted trapezoid, i.e., wider at the top and narrower at the bottom, which facilitates the fabrication of the conductive layer.

[0022] Preferably, the groove is a strip-shaped groove.

[0023] Preferably, the conductor is a conductive strip.

[0024] Preferably, the conductor has a multilayer structure or a hollow structure.

[0025] Preferably, the conductivity of the conductive layer is greater than the conductivity of the conductor.

[0026] Preferably, the conductor is provided with a connector, which is used to connect multiple conductors together to form a conductive structure.

[0027] Preferably, the material of the connector includes a metallic material and / or a carbon material. Exemplarily, the metallic material includes any one or a combination of at least two of Au, Pt, Pd, Ag, Cu, Al, Co, Cr, Zn, Ni, Ti, W, Fe, Sn, or In.

[0028] Preferably, the inductor further includes a terminal electrode, which is electrically connected to the exposed end of the winding.

[0029] Preferably, the material of the terminal electrode includes Ag.

[0030] In a second aspect, the present invention provides a method for fabricating an inductor as described in the first aspect, the method comprising the following steps:

[0031] The inductor is obtained by at least partially placing a conductor in a magnetic component and then forming a winding by placing a conductive layer on the surface of the conductor.

[0032] The preparation method provided by this invention is simple, and the magnetic body and winding are formed separately, so a magnetic body with higher density can be prepared to improve electromagnetic performance.

[0033] Preferably, the preparation method includes the following steps:

[0034] (a) Prepare a first magnetic body with grooves.

[0035] (b) A conductor is placed in the groove of the first magnetic body, and a conductive layer is formed in the groove by a metallization process, such that the conductive layer is disposed on the surface of the conductor and located between the conductor and the groove, to obtain a winding, the winding being attached to the inner wall of the groove.

[0036] (c) A second magnetic body is stacked on the first surface of the first magnetic body and covers the winding.

[0037] Preferably, the method for preparing the first magnetic body with grooves in step (a) includes:

[0038] The soft magnetic powder and resin are mixed and granulated to obtain granulated powder.

[0039] The granulated powder is molded and then subjected to a first heat treatment to obtain the first magnetic body having at least one strip-shaped groove.

[0040] Preferably, the resin content is 2-10% of the mass of the soft magnetic powder, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0041] In this invention, resin is used as an adhesive to bond the soft magnetic powder together during the molding process.

[0042] Preferably, the soft magnetic powder includes any one or a combination of at least two of the following: iron-silicon-aluminum powder, iron-silicon powder, iron-nickel powder, iron-silicon-chromium powder, iron-nickel powder, amorphous nanocrystalline powder, or carbonyl iron powder.

[0043] Preferably, the resin comprises a thermosetting resin and / or a thermoplastic resin. Exemplarily, the thermosetting resin may be any one or a combination of at least two of epoxy resin, diallyl phthalate resin, phenolic resin, polyimide, polyamide-imide, or silicone resin; the thermoplastic resin may be any one or a combination of at least two of polyolefin, fluoropolymer, polyamide, polyester, polycarbonate, polyoxymethylene, polypropylene-dodecene-styrene (ABS resin), or polystyrene-acrylonitrile (SAN or AS resin).

[0044] Preferably, the compression molding pressure is 2-24 T / cm. 2 For example, it could be 2T / cm 2 5T / cm 2 10T / cm 2 15T / cm 2 20T / cm 2 Or 24T / cm 2 wait.

[0045] Preferably, the first heat treatment is heat annealing or heat curing.

[0046] It should be noted that compression molding causes elastic and plastic deformation of the soft magnetic powder, and the greater the molding pressure, the more severe the deformation. Therefore, heat treatment is required to remove internal stress. Hot annealing involves placing the first molded magnetic body in an annealing furnace for annealing. This not only releases the residual stress introduced by the molding process but also eliminates internal defects generated during the magnetic body's fabrication. Therefore, hot annealing can improve the initial permeability of the magnetic body, reduce iron loss, and increase its mechanical strength. Thermosetting is used to cure the resin binding the soft magnetic powder. In other words, the temperature and purpose of the heat treatment process are determined by the desired electromagnetic properties of the first magnetic body and the thermal properties of the binding material.

[0047] Preferably, the heat annealing temperature is 300-1000℃, for example, it can be 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, or 1000℃. For example, the compression molding pressure is 10-24 T / cm. 2 After annealing, it can form a density of 50-150 g / cm³. 3 , and / or a first magnetic body with high density and high permeability of 50-200 (μ=50-200).

[0048] In this invention, if the annealing temperature is too low, it will not be enough to release the internal residual stress, resulting in low permeability and high loss; if the annealing temperature is too high, it will cause the insulating layer on the powder surface to be damaged, which will reduce the initial permeability and increase the eddy current loss.

[0049] Preferably, the temperature for heat curing is 100-300℃, for example, it can be 100℃, 200℃ or 300℃.

[0050] Preferably, the metallization process in step (b) includes any one or a combination of at least two of the following: coating, sputtering, vapor deposition, electroplating, spraying, aerosol deposition, or thermal spraying. For example, electroplating can be used to form a conductive layer using a thick copper process.

[0051] Preferably, the application method includes the following steps:

[0052] A conductive paste is applied between the conductor and the inner wall of the groove, followed by a second heat treatment to obtain the conductive layer.

[0053] It should be noted that the second heat treatment can be the same as the first heat treatment, that is, when the first heat treatment is performed, a conductor and a conductive paste are already placed in the groove, and the first magnetic body and the conductive paste are heat treated together; the second heat treatment can also be different from the first heat treatment, that is, when the first heat treatment and the second heat treatment are performed separately, the second heat treatment can be performed after the first heat treatment is completed.

[0054] Preferably, the temperature of the second heat treatment is greater than 300°C, for example, it can be 320°C, 350°C, 400°C, 450°C, or 500°C, etc., and the conductive slurry includes conductive powder and organic solvent. For example, the conductive powder can be Ag powder, and after the second heat treatment, the Ag powder is sintered together.

[0055] Preferably, the temperature of the second heat treatment is less than or equal to 300°C, for example, it can be 300°C, 280°C, 250°C, 200°C or 150°C, etc. The conductive slurry includes conductive particles and organic solvent. The conductive particles include nano-sized particles and micro-sized particles. For example, both the micro-sized conductive particles and the nano-sized conductive particles are silver. At the second heat treatment temperature, the nano-sized silver particles melt and are connected with the micro-sized silver particles to form a whole.

[0056] Preferably, in step (c), the method of stacking the second magnetic body includes hot pressing or covering.

[0057] Preferably, the hot pressing method includes the following steps:

[0058] The mixture of magnetic powder and resin is hot-pressed onto the first surface of the first magnetic body.

[0059] Preferably, in the mixture of magnetic powder and resin, the resin content is 50-95% by mass, for example, it can be 50%, 60%, 70%, 80%, 90% or 95%, etc.

[0060] Preferably, the pressure of the hot pressing is less than the molding pressure of the first magnetic body.

[0061] Preferably, in the mixture of magnetic powder and resin, the magnetic powder includes any one or a combination of at least two of the following: iron-silicon-aluminum powder, iron-silicon powder, iron-nickel powder, iron-silicon-chromium powder, iron-nickel powder, amorphous nanocrystalline powder, or carbonyl iron powder.

[0062] Preferably, in the mixture of magnetic powder and resin, the resin includes thermosetting resin and / or thermoplastic resin. Exemplarily, the thermosetting resin may be any one or a combination of at least two of epoxy resin, diallyl phthalate resin, phenolic resin, polyimide, polyamide-imide, or silicone resin; the thermoplastic resin may be any one or a combination of at least two of polyolefin, fluoropolymer, polyamide, polyester, polycarbonate, polyoxymethylene, polypropylene-dodecene-styrene (ABS resin), or polystyrene-acrylonitrile (SAN or AS resin).

[0063] Preferably, the covering method includes the following steps:

[0064] The magnetic plate is placed on the first surface of the first magnetic body.

[0065] It should be noted that magnetic plates are usually made of ferromagnetic materials (such as iron, nickel, cobalt and their alloys) or magnetic materials such as ferrites. They can also be made by coating or pasting magnetic coatings or magnetic films onto ordinary plates (such as plastic plates, metal plates, etc.) to give them magnetism.

[0066] Preferably, before the magnetic plate is applied to the first surface of the first magnetic body, an adhesive is first applied to the area where the first magnetic body and the magnetic plate are connected. Examples include epoxy resin adhesive, polyurethane adhesive, or silicone adhesive.

[0067] Preferably, when the number of grooves in the first magnetic body in step (a) is at least two, step (c) after the second magnetic body is stacked, a cutting process is also performed to form several independent inductors.

[0068] Preferably, the preparation method further includes step (d) after step (c), wherein step (d) includes:

[0069] Electrodes are formed on the inductor obtained in step (c) such that the electrodes are electrically connected to the exposed end of the winding.

[0070] Preferably, the method for forming the electrode includes coating, welding, or metallization.

[0071] Preferably, the coating method includes the following steps:

[0072] The electrode is obtained by coating the inductor with a conductive paste and then performing thermal processing.

[0073] Preferably, the thermal processing method includes curing or sintering.

[0074] Preferably, when the thermal processing is performed by curing, the conductive slurry comprises metal powder particles and resin. For example, the metal powder particles may be Ag powder particles.

[0075] Preferably, when the thermal processing is sintering, the conductive paste includes metal powder particles, an inorganic binder, and an organic binder. For example, the metal powder particles may be Ag powder particles, the inorganic binder may be glass powder, alumina, or zinc oxide, and the organic binder may be ethyl cellulose, acrylic resin, or polyvinyl butyral.

[0076] Preferably, the sintering temperature is 600-1000℃, for example, it can be 600℃, 700℃, 800℃, 900℃ or 1000℃.

[0077] Preferably, when the electrode is formed by welding, the electrode is a pre-fabricated part, that is, the finished electrode is welded together with the winding end exposed in the inductor.

[0078] Preferably, the metallization electrode method includes any one or a combination of at least two of physical vapor deposition, chemical vapor deposition, sputtering, electroplating, or electroless plating.

[0079] Preferably, when the electrode is formed by a metallization electrode method, the electrode includes at least one conductive metal layer.

[0080] Thirdly, the present invention provides an electronic device comprising an inductor as described in the first aspect.

[0081] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] This invention employs a combination of a conductor and a conductive layer to form the winding. This allows for a reduction in the gap between the winding and the magnetic material when manufacturing inductors of the same volume, thereby reducing the current-carrying capacity (DCR) and improving its conductivity. Furthermore, by placing the winding within the magnetic component, and since the magnetic component and winding are molded separately, a higher density magnetic material can be manufactured, thus improving electromagnetic performance. Attached Figure Description

[0084] Figure 1 This is a schematic diagram of the combined structure of the inductor provided in Embodiment 1 of the present invention.

[0085] Figure 2 This is a schematic cross-sectional view of the inductor assembly provided in Embodiment 1 of the present invention.

[0086] Figure 3 This is a schematic diagram of the structure of the first magnetic body provided in Embodiment 1 of the present invention.

[0087] Figure 4 This is a schematic diagram of the structure after step (2) provided in Embodiment 1 of the present invention.

[0088] Figure 5 This is a schematic diagram of the structure after step (3) provided in Embodiment 1 of the present invention.

[0089] Figure 6 This is a schematic diagram of the structure after step (4) provided in Embodiment 1 of the present invention.

[0090] Figure 7 This is a schematic diagram of the structure after step (5) provided in Embodiment 1 of the present invention.

[0091] Figure 8 This is a schematic diagram of the structure after step (6) provided in Embodiment 1 of the present invention.

[0092] Figure 9 This is a schematic cross-sectional view of the inductor assembly provided in Embodiment 10 of the present invention.

[0093] Figure 10 This is a schematic cross-sectional view of the inductor assembly provided in Embodiment 11 of the present invention.

[0094] Figure 11 This is a schematic cross-sectional view of the inductor assembly provided in Embodiment 12 of the present invention.

[0095] Figure 12 This is a schematic diagram of the structure after step (2) provided in Embodiment 13 of the present invention.

[0096] Figure 13 This is a schematic diagram of the combined structure of the inductor provided in Embodiment 13 of the present invention.

[0097] Wherein, 1-inductor; 2-first magnetic body; 3-strip groove; 4-conductor; 5-conducting layer; 6-second magnetic body; 7-cutting line; 8-electrode; 9-conducting pin. Detailed Implementation

[0098] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0099] Example 1

[0100] This embodiment provides an inductor, and a schematic diagram of the assembled structure of the inductor is shown below. Figure 1 As shown, its cross-sectional schematic diagram is as follows. Figure 2 As shown, the inductor 1 includes:

[0101] A first magnetic body 2 has a strip-shaped groove 3 on its first surface. The three strip-shaped grooves 3 penetrate the first surface of the first magnetic body 2 and are spaced apart from each other and arranged in parallel.

[0102] The winding is disposed in the strip groove 3. The winding includes a conductor 4 and a conductive layer 5 disposed between the conductor 4 and the strip groove 3. The conductive layer 5 is formed between the conductor 4 and the inner wall of the strip groove 3, and covers the upper end face of the conductor 4. The upper end face of the conductive layer 5 is flush with the first surface of the first magnetic body 2. The conductor 4 is a copper strip, and the material of the conductive layer 5 is copper. The cross-section of the strip groove 3 is rectangular, and the cross-section of the copper strip is rectangular. The spacing between the sidewalls of the conductor 4 and the strip groove 3 is equal, and the conductivity of the conductive layer 5 is greater than the conductivity of the conductor 4.

[0103] The second magnetic body 6 is stacked on the first surface of the first magnetic body 2 and covers the winding.

[0104] The inductor also includes a terminal electrode located in the electrode region of the inductor and electrically connected to the exposed end of the winding; the terminal electrode is made of Ag.

[0105] It should be understood that, Figure 1 The horizontal and vertical intersecting lines in the diagram represent cutting lines, used to cut the inductor assembly into several independent inductors.

[0106] This embodiment also provides a method for manufacturing the above-mentioned inductor, including the following steps:

[0107] (1) Prepare a first magnetic body 2 with three strip-shaped grooves 3, such as Figure 3 As shown:

[0108] An insulating layer is formed on the outer surface of the iron-silicon-aluminum powder. The insulating layer is made of aluminum phosphate. Then, the iron-silicon-aluminum powder with the insulating layer and epoxy resin are mixed at a mass ratio of 1:0.1 and granulated to obtain granulated powder.

[0109] The granulated powder is filled into the mold cavity at 13T / cm. 2 The material is molded under pressure and then placed inside an annealing furnace for heat treatment (i.e., hot annealing) at 600°C to obtain the first magnetic body 2. It is understood that the groove 3 can be formed by molding or by processing after molding.

[0110] (2) Place the copper strip in the strip-shaped groove 3 of the first magnetic body 2, such that the upper end surface of the copper strip is lower than the first surface of the first magnetic body 2. Figure 4 As shown.

[0111] (3) Based on electroplating, a conductive layer 5 is formed in the strip groove 3 of the first magnetic body 2 using a thick copper process to obtain the winding, such as... Figure 5 As shown; wherein, the conductive layer 5 is formed between the copper strip and the inner wall of the strip groove, and covers the upper end surface of the copper strip, and the upper end surface of the conductive layer 5 is flush with the first surface of the first magnetic body 2. For example, the thickness of the copper strip is 0.1 mm, and the thickness of the conductive layer is 0.15 mm.

[0112] (4) A mixture of iron-silicon-aluminum powder and epoxy resin is hot-pressed onto the first surface of the first magnetic body 2 and covers the winding to form a second magnetic body 6, thus obtaining an inductor assembly, such as... Figure 6 As shown; wherein, in the mixture of iron-silicon-aluminum powder and epoxy resin, the mass content of epoxy resin is 70%.

[0113] (5) The inductor assembly is cut to form several independent inductors 1, such as... Figure 7 As shown in the figure, the horizontal and vertical intersecting lines represent cutting lines.

[0114] (6) Apply conductive silver paste to the electrode area of ​​the inductor 1 and connect it to the exposed end of the winding, then cure it to form electrode 8, as shown. Figure 8 As shown (where the right image is a flip view of the left image); wherein, the conductive paste comprises Ag powder particles and epoxy resin, and the mass content of epoxy resin is 5%.

[0115] Example 2

[0116] The difference between this embodiment and embodiment 1 is that the thermal annealing in step (1) is replaced by thermal curing, that is, the first magnetic body formed by molding is cured at 200°C.

[0117] The remaining preparation methods and parameters are consistent with those in Example 1.

[0118] Example 3

[0119] The difference between this embodiment and embodiment 1 is that the mixture of iron-silicon-aluminum powder and epoxy resin in step (4) is replaced by a magnetic plate, and the magnetic plate is directly covered on the first surface of the first magnetic body.

[0120] The remaining preparation methods and parameters are consistent with those in Example 1.

[0121] Example 4

[0122] The difference between this embodiment and embodiment 3 is that, before the magnetic plate is placed on top, an epoxy resin adhesive is first applied to the area where the first magnetic body and the magnetic plate are connected, and then the magnetic plate is placed on top of the first magnetic body.

[0123] The remaining preparation methods and parameters are consistent with those in Example 3.

[0124] Example 5

[0125] The difference between this embodiment and embodiment 1 is that the curing in step (6) is replaced by sintering at 600°C, and the conductive paste includes Ag powder particles, alumina binder and ethyl cellulose binder.

[0126] The remaining preparation methods and parameters are consistent with those in Example 1.

[0127] Example 6

[0128] The difference between this embodiment and embodiment 1 is that the electrode preparation method in step (6) is a welding method, which includes welding a copper wire frame to the exposed winding end of the inductor.

[0129] The remaining preparation methods and parameters are consistent with those in Example 1.

[0130] Example 7

[0131] The difference between this embodiment and embodiment 1 is that the electroplating method in step (3) is replaced by a coating method, which includes the following steps:

[0132] A conductive slurry is applied between the conductor and the inner wall of the strip groove, and then sintered at 700°C to form a conductive layer; wherein the conductive slurry includes Ag powder.

[0133] The remaining preparation methods and parameters are consistent with those in Example 1.

[0134] Example 8

[0135] The difference between this embodiment and embodiment 1 is that the electroplating method in step (3) is replaced by a coating method, which includes the following steps:

[0136] A conductive paste is applied between the conductor and the inner wall of the strip groove, and then a conductive layer is formed at 250°C; wherein the conductive paste includes nano-sized Ag particles and micro-sized Ag particles.

[0137] The remaining preparation methods and parameters are consistent with those in Example 1.

[0138] Example 9

[0139] The difference between this embodiment and embodiment 1 is that a connector is provided on the conductor. The connector is used to connect multiple conductors together to form a conductive structure, thereby placing the conductors one by one in the strip groove of the first magnetic body.

[0140] The remaining preparation methods and parameters are consistent with those in Example 1.

[0141] Example 10

[0142] The difference between this embodiment and Embodiment 1 is that, in the inductor, the conductor and conductive layer include the following cases, such as... Figure 9 As shown:

[0143] The conductive layer is formed between the conductor and the inner wall of the strip groove, and the upper end face of the conductive layer, the upper end face of the conductor, and the first surface of the first magnetic body are flush. The lower end face of the conductor is attached to the bottom surface of the groove.

[0144] The conductive layer is formed between the conductor and the inner wall of the strip groove. The upper surface of the conductive layer is flush with the upper surface of the conductor and is lower than the first surface of the first magnetic body.

[0145] The conductive layer is formed between the conductor and the inner wall of the strip groove, and covers the upper end face of the conductor, and is formed between the lower end face of the conductor and the bottom surface of the strip groove, and the upper end face of the conductive layer is flush with the first surface of the first magnetic body.

[0146] The remaining preparation methods and parameters are consistent with those in Example 1.

[0147] Example 11

[0148] The difference between this embodiment and Embodiment 1 is that, in the inductor, the conductor and conductive layer include the following cases, such as... Figure 10 As shown:

[0149] The conductive layer is formed between the conductor and the inner wall of the strip groove, and covers the upper end face of the conductor. The upper end face of the conductive layer is flush with the first surface of the first magnetic body, and the lower end face of the conductor is attached to the bottom surface of the strip groove. The cross-sectional shape of the conductor is a trapezoid, that is, along the thickness direction of the conductor, the distance between the conductor and the side wall of the groove gradually increases.

[0150] The conductive layer is formed between the conductor and the inner wall of the strip groove, and between the lower end face of the conductor and the bottom surface of the strip groove, and the upper end face of the conductive layer, the upper end face of the conductor, and the first surface of the first magnetic body are flush.

[0151] The conductive layer is formed between the conductor and the inner wall of the strip groove, and covers the upper end face of the conductor. The upper end face of the conductive layer is flush with the first surface of the first magnetic body, and the lower end face of the conductor is attached to the bottom surface of the groove. The conductor has a trapezoidal cross-sectional shape, that is, the distance between the conductor and the side wall of the groove gradually increases along the thickness direction of the conductor. The conductor has a hollow structure.

[0152] The remaining preparation methods and parameters are consistent with those in Example 1.

[0153] Example 12

[0154] The difference between this embodiment and Embodiment 1 is that the cross-section of the groove is an inverted trapezoid, and the conductor and conductive layer in the inductor include the following: Figure 11 As shown:

[0155] The conductive layer is formed between the conductor and the inner wall of the strip groove, and covers the upper end face of the conductor. The upper end face of the conductive layer is flush with the first surface of the first magnetic body, and the lower end face of the conductor is attached to the bottom surface of the groove. The cross-sectional shape of the conductor is a trapezoid and a rectangle.

[0156] The conductive layer is formed between the conductor and the inner wall of the strip groove, and the upper end face of the conductive layer, the upper end face of the conductor, and the first surface of the first magnetic body are flush. The lower end face of the conductor is attached to the bottom surface of the groove.

[0157] The remaining preparation methods and parameters are consistent with those in Example 1.

[0158] Example 13

[0159] The difference between this embodiment and Embodiment 1 is that no terminal electrodes are provided on the inductor. Please refer to [link / reference]. Figure 12 and Figure 13 The conductor 4 is provided with conductive pins 9, which protrude from the side of the conductor 4 away from the first magnetic body 2, extend toward the second magnetic body 6 and penetrate the second magnetic body 6; the conductive pins 9 are spaced apart along the extension direction of the conductor 4, and each independent inductor 1 after cutting includes two conductive pins 9 exposed on the second magnetic body 6 for electrical connection with external circuit.

[0160] The density of the first magnetic body 2 is greater than that of the second magnetic body 6, the permeability of the first magnetic body 2 is greater than that of the second magnetic body 6, the material of the conductive pin 9 is the same as that of the conductive body 4, and the hardness of the first magnetic body 2 is greater than that of the second magnetic body 6.

[0161] The remaining preparation methods and parameters are consistent with those in Example 1.

[0162] It should be understood that, Figure 13 The horizontal and vertical intersecting lines in the diagram represent cutting lines, used to cut the inductor assembly into several independent inductors, and each independent inductor includes two conductive pins exposed to the second magnetic body.

[0163] Example 14

[0164] The difference between this embodiment and embodiment 1 is that the temperature of the heat annealing in step (1) is 300°C.

[0165] The remaining preparation methods and parameters are consistent with those in Example 1.

[0166] Example 15

[0167] The difference between this embodiment and embodiment 1 is that the temperature of the heat annealing in step (1) is 1100℃.

[0168] The remaining preparation methods and parameters are consistent with those in Example 1.

[0169] Specifically, a comparison between Example 1 and Examples 14-15 shows that if the annealing temperature is too low, i.e. as low as 300°C, the internal residual stress is not released at such a low temperature, which can easily lead to low permeability and high loss. If the annealing temperature is too high, i.e. as high as 1100°C, the insulating layer on the powder surface can be damaged, which can reduce the initial permeability and increase eddy current loss.

[0170] In summary, this invention utilizes a specific combination of conductors and conductive layers to form the winding. This allows for the reduction or elimination of the gap between the winding and the magnetic material when fabricating inductors of the same volume, thereby reducing the inductor's DCR (directly correlated with winding resistivity and inversely correlated with winding cross-section) and improving its current-carrying capacity. Furthermore, by placing the conductor within the strip-shaped groove of the first magnetic material, and then filling the gap between the conductor and the magnetic material with a conductive layer, followed by covering the winding with a second magnetic material, the invention avoids the limitations imposed by the winding on molding pressure in the existing one-piece molding process. This allows for the fabrication of a higher density magnetic material, thus improving electromagnetic performance. Additionally, when the conductor also has protruding conductive leads, the first magnetic material is formed using high-voltage pressing, and the second magnetic material is formed using low-voltage pressing. This ensures the electromagnetic performance of the inductor while preventing the formation of the second magnetic material from affecting the conductive leads.

[0171] It is understandable that, based on the above embodiments, when the preparation method does not include step (3), that is, when the conductive layer 5 is not provided between the conductor 4 and the groove 3, the magnetic mixture is directly filled into the gap between the conductor 4 and the groove 3 through step (4). The conductor 4 may also partially protrude from the groove 3. This preparation method can effectively connect the second magnetic body 5 to the conductor 4. However, when the overall size of the inductor 1 is small, it is easier to achieve and increase the current conduction capacity by directly forming the conductive layer 5 in the gap between the conductor 4 and the groove 3. It is also understandable that, based on the above embodiments, when the preparation method does not include step (2), that is, when the conductive layer is directly provided in the groove to form the winding, when the overall size of the inductor 1 is large, higher electromagnetic performance is required, or when a larger cross-section winding is required for the same volume, directly forming the winding through metallization results in longer production time and higher cost.

[0172] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An inductor, characterized in that, The inductor includes a winding and a magnetic element that at least partially covers the winding; the winding includes a conductor and a conductive layer disposed on the surface of the conductive layer.

2. The inductor according to claim 1, characterized in that, The magnetic component includes: A first magnetic body has a groove on its first surface, and the winding is disposed in the groove, with the winding fitting against the inner wall of the groove. A second magnetic body is stacked on the first surface of the first magnetic body and covers the winding; Preferably, the conductor is further provided with conductive pins, which protrude from the side of the conductor away from the first magnetic body, extend toward the second magnetic body and penetrate the second magnetic body; wherein the density of the first magnetic body is greater than the density of the second magnetic body, and / or the permeability of the first magnetic body is greater than the permeability of the second magnetic body.

3. The inductor according to claim 2, characterized in that, The materials of the conductor and the conductive layer each independently include metallic materials and / or carbon materials; Preferably, the metallic material includes any one or a combination of at least two of Au, Pt, Pd, Ag, Cu, Al, Co, Cr, Zn, Ni, Ti, W, Fe, Sn, or In; Preferably, the positional relationship between the conductive layer and the conductor includes at least one of the following: The conductive layer is formed between the conductor and the inner wall of the groove, and covers the upper end face of the conductor; The conductive layer is formed between the conductor and the inner wall of the groove, and the upper end face of the conductive layer is flush with the upper end face of the conductor. Preferably, the distance between the conductor and the sidewall of the groove is equal, or the distance gradually increases along the thickness direction of the conductor; Preferably, the conductor has a multilayer structure or a hollow structure; Preferably, the conductivity of the conductive layer is greater than the conductivity of the conductor.

4. The inductor according to claim 1, characterized in that, The conductor is provided with a connector, which is used to connect multiple conductors together to form a conductive structure. Preferably, the material of the connector includes metallic materials and / or carbon materials; Preferably, the inductor further includes a terminal electrode, which is electrically connected to the exposed end of the winding.

5. A method for manufacturing an inductor as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: The inductor is obtained by at least partially placing a conductor in a magnetic component and then forming a winding by placing a conductive layer on the surface of the conductor.

6. The preparation method according to claim 5, characterized in that, The preparation method includes the following steps: (a) Preparing a first magnetic body with grooves; (b) A conductor is placed in the groove of the first magnetic body, and then a conductive layer is formed in the groove by a metallization process, such that the conductive layer is disposed on the surface of the conductor and located between the conductor and the groove, to obtain a winding; (c) A second magnetic body is stacked on the first surface of the first magnetic body and covers the winding.

7. The preparation method according to claim 6, characterized in that, The method for preparing the first magnetic body with grooves in step (a) includes: The soft magnetic powder and resin are mixed and granulated to obtain granulated powder; The granulated powder is molded and then subjected to a first heat treatment to obtain the first magnetic body having at least one groove; Preferably, the soft magnetic powder includes any one or a combination of at least two of the following: iron-silicon-aluminum powder, iron-silicon powder, iron-nickel powder, iron-silicon-chromium powder, iron-nickel powder, amorphous nanocrystalline powder, or carbonyl iron powder; Preferably, the resin includes thermosetting resin and / or thermoplastic resin; Preferably, the compression molding pressure is 2-24 T / cm. 2 ; Preferably, the first heat treatment is heat annealing or heat curing; Preferably, the temperature of the heat annealing is 300-1000℃.

8. The preparation method according to claim 6 or 7, characterized in that, The metallization process described in step (b) includes any one or a combination of at least two of the following: coating, sputtering, vapor deposition, electroplating, spraying, aerosol deposition, or thermal spraying. Preferably, the application method includes the following steps: A conductive paste is applied between the conductor and the inner wall of the groove, and then a second heat treatment is performed to obtain the conductive layer. Preferably, in step (c), the method of stacking the second magnetic body includes hot pressing or covering. Preferably, the hot pressing method includes the following steps: The mixture of magnetic powder and resin is hot-pressed onto the first surface of the first magnetic body; Preferably, in the mixture of magnetic powder and resin, the resin content is 50-95% by mass; Preferably, the covering method includes the following steps: The magnetic plate is placed on the first surface of the first magnetic body.

9. The preparation method according to any one of claims 6-8, characterized in that, When the number of grooves in the first magnetic body is at least two in step (a), in step (c) after the second magnetic body is stacked, a cutting process is also performed to form several independent inductors; Preferably, the preparation method further includes step (d) after step (c), wherein step (d) includes: Electrodes are formed on the inductor obtained in step (c) such that the electrodes are electrically connected to the exposed ends of the winding; Preferably, the method for forming the electrode includes coating, welding, or metallization.

10. An electronic device, characterized in that, The electronic device includes an inductor as described in any one of claims 1-4.

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