Laminated inductor and preparation method and application thereof

Abstract

The invention relates to a laminated inductor and a preparation method and application thereof. The laminated inductor comprises laminated magnetic powder cores, the layered magnetic powder core comprises a soft magnetic metal layer and an open annular copper conductor embedded in the soft magnetic metal layer; in every two adjacent layers of layered magnetic powder cores, openings of the open annular copper conductors are arranged in a staggered mode, and the second open end of one layered magnetic powder core is connected with the first open end of the other layered magnetic powder core. According to the laminated inductor and the preparation method thereof, the inductance value of the laminated inductor is increased, high inductance value (larger than or equal to 1000 mu H) can be achieved while large current (larger than or equal to 200 A) is coped with, the preparation method is simple, and automatic production is easy to achieve.

Description

Technical Field

[0001] The invention belongs to the technical field of inductor components and relates to a laminated inductor and a preparation method and application thereof. Background Art

[0002] Portable active devices are developing in the direction of integration, miniaturization and high precision. Inductors are important components for purifying current, converting energy and shielding interference. Inductors are divided into winding inductors, stacked inductors and thin film inductors according to the manufacturing process. One-piece molded inductors are both winding inductors and stacked inductors. They are a kind of comprehensive inductor. The production process is highly mechanized, the production efficiency is higher than that of traditional winding inductors, and the product performance is uniform and stable. In addition, the one-piece molded inductor uses soft magnetic powder to wrap the copper conductor, which has a better shielding effect.

[0003] In order to improve the ability of one-piece molded inductors to withstand large currents, a new type of inductor with a single-turn copper sheet instead of a copper coil has been developed in recent years. Metal insulation powder, as a soft magnetic material, can be subjected to high-temperature heat treatment above 600°C, which improves the saturation magnetization strength, magnetic permeability and efficiency of the inductor. However, one-piece molded inductors have the following disadvantages. First, in order to avoid the metal powder piercing the insulation layer due to excessive pressure, one-piece molded inductors cannot be formed using high-pressure pressing, resulting in the metal powder being unable to be compacted. The lower density leads to lower magnetic permeability and it is impossible to obtain high inductance. Second, in order to prevent the coil from short-circuiting, the coil needs to be coated with resin, which makes it impossible to perform high-temperature heat treatment on the one-piece molded inductor. The existing internal stress leads to high losses and the risk of easy cracking.

[0004] CN114597015A discloses a laminated inductor and its preparation method and application, wherein the laminated inductor is a power inductor formed by laminating a soft magnetic metal powder core and a first conductor printed on the surface of the powder core, the soft magnetic powder core is a soft magnetic body made of alloy magnetic powder through molding and high temperature heat treatment, the soft magnetic body has a through hole filled with a second conductor, and the first conductor and the second conductor are connected to form a conductor coil. Although this technical solution solves the problem of low magnetic permeability of the existing laminated inductor and achieves the purpose of the laminated inductor to withstand large current, the first conductor adopts a relatively high-cost silver paste printing process, and the first conductor has various and complex shapes, which is not conducive to assembly and automated production, and is easy to cause coil short circuit and open circuit, resulting in increased overall efficiency and cost.

[0005] CN115938718A discloses a direct-insert integrated co-fired inductor, which consists of two parts: soft magnetic metal powder and inverted U-shaped copper conductor. The metal magnetic powder is formed using a high pressure of 1700Mpa-2000Mpa, and has a high density. The product is subjected to gradient annealing treatment, and the maximum temperature reaches 800°C, which can eliminate the internal stress generated during molding. However, the inductor provided by this technical solution has only one turn of wire, and the total inductance and magnetic core volume utilization are low. In addition, the U-shaped wire is difficult to fix in the porcelain powder, and the mold structure is complex, which easily causes the wire to be eccentric and the inductor to crack.

[0006] Therefore, it is necessary to solve the problems of low inductance and complex process of the prior art multilayer inductor. Summary of the invention

[0007] In view of the deficiencies in the prior art, the object of the present invention is to provide a multilayer inductor and a preparation method and application thereof. The multilayer inductor and the preparation method thereof provided by the present invention not only improve the inductance value of the multilayer inductor, and can achieve high inductance (≥1000μH) while handling large current (≥200A), but also the preparation method is simple and easy to realize automated production.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a laminated inductor, comprising a laminated magnetic powder core arranged in layers; the laminated magnetic powder core comprises a soft magnetic metal layer and an open ring-shaped copper conductor embedded in the soft magnetic metal layer; the two ends of the opening of the open ring-shaped copper conductor are respectively a first opening end and a second opening end, and the first opening end and the second opening end expose the soft magnetic metal layer; in two adjacent layers of the laminated magnetic powder core, the openings of the open ring-shaped copper conductors are staggered, and the second opening upper end of one laminated magnetic powder core is connected to the first opening lower end of another laminated magnetic powder core.

[0010] The laminated inductor provided by the present invention has a simple structure. Through a simple stacking arrangement and in combination with a layered magnetic powder core structure, it can handle large currents (≥200A) while achieving high inductance (≥1000μH). In addition, the preparation method is simple and automated production can be easily realized.

[0011] Preferably, the soft magnetic metal layer is composed of any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder, or a combination of at least two of them.

[0012] The present invention makes the composition of the soft magnetic metal layer include any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or alloy metal magnetic powder or a combination of at least two of them. The main and secondary powder combinations can be selected. For example, finer submicron metal magnetic powder is used to fill the gaps between the soft magnetic amorphous magnetic powders, so that the internal distribution of the layered magnetic powder core is more compact and uniform, the magnetic resistance is reduced, the magnetic permeability is improved, and the performance of the laminated inductor is enhanced.

[0013] Preferably, the soft magnetic amorphous magnetic powder comprises FeSiB amorphous magnetic powder;

[0014] Preferably, the nanocrystalline magnetic powder comprises FeSiCuBPNd multi-element alloy magnetic powder;

[0015] Preferably, the submicron metal magnetic powder includes any one of sendust magnetic powder, iron silicon nickel magnetic powder, iron silicon chromium magnetic powder, iron nickel magnetic powder or carbonyl iron powder, or a combination of at least two thereof.

[0016] Preferably, the ratio of the average particle size of the soft magnetic amorphous magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1;

[0017] Preferably, the ratio of the average particle size of the nanocrystalline magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1;.

[0018] Preferably, the average particle size of the soft magnetic amorphous magnetic powder is less than 74 μm.

[0019] Preferably, the average particle size of the nanocrystalline magnetic powder is less than 74 μm.

[0020] Preferably, the mass ratio of the total mass of the soft magnetic amorphous magnetic powder and the nanocrystalline magnetic powder to the mass ratio of the submicron metal magnetic powder is 15:1-20:1.

[0021] Preferably, the open ring-shaped copper conductor has a width of 0.5 mm to 3 mm and a thickness of 0.2 mm to 1 mm.

[0022] Preferably, in any of the open ring-shaped copper conductors, the distance between the first open end and the second open end is 1 to 2 times the width of the open ring-shaped copper conductor. Further preferably, the distance between the first open end and the second open end is 0.5 mm to 6 mm.

[0023] Preferably, the first opening end and the second opening end are respectively and independently welded to a conductive joint; the distance of the conductive joint beyond the first opening end or the second opening end does not exceed 1 mm.

[0024] Preferably, the soft magnetic metal layer further includes a binder.

[0025] In a second aspect, the present invention provides a method for preparing the multilayer inductor according to the first aspect, the method comprising the following steps:

[0026] The open annular copper conductor and the soft magnetic metal powder are assembled to form an integrated inductor; the integrated inductor is heated and cured, and simply processed to expose the first open upper end and the second open lower end of the open annular copper conductor to obtain a layered magnetic powder core.

[0027] The required number of layered magnetic powder cores are stacked so that the openings of the open annular copper conductors in two adjacent layers of the layered magnetic powder cores are staggered and the second open end of one layered magnetic powder core is connected to the first open end of another layered magnetic powder core; and then pressure molding and heat treatment are performed in sequence to obtain the laminated inductor.

[0028] Preferably, when a desired number of layered magnetic powder cores are stacked, a bonding component, such as a bonding silicone resin, is provided on the contact surfaces of adjacent layered magnetic powder cores.

[0029] Preferably, the temperature of the heating and curing treatment does not exceed 220°C, preferably 190°C-210°C.

[0030] Preferably, the heat preservation time of the heating and curing treatment is 25min-30min.

[0031] Preferably, the molding pressure is 80MPa-120MPa.

[0032] Preferably, the pressure of the pressurizing molding is 580MPa-620MPa.

[0033] Preferably, the temperature of the heat treatment is ≤210°C.

[0034] Preferably, the soft magnetic metal powder includes any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder, or a combination of at least two of them.

[0035] Preferably, the soft magnetic metal powder is soft magnetic metal powder that has been subjected to insulation treatment.

[0036] Preferably, the insulation treatment is performed using inorganic acid and / or insulating oxide.

[0037] Preferably, the inorganic acid comprises phosphoric acid and / or chromic acid.

[0038] Preferably, the insulating oxide includes any one of silicon dioxide, magnesium oxide or aluminum oxide, or a combination of at least two thereof.

[0039] In a third aspect, the present invention provides an application of the multilayer inductor described in the first aspect, wherein the multilayer inductor is used for a circuit board.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The laminated inductor provided by the present invention has a simple structure. Through a simple stacking arrangement and in combination with a layered magnetic powder core structure, it can handle large currents (≥200A) while achieving high inductance (≥1000μH). In addition, the preparation method is simple and automated production can be easily realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the structure of the layered magnetic powder core in Example 1 of the present invention.

[0043] Figure 2 FIG. 1 is a schematic diagram of the structure of the multilayer inductor in Example 1 of the present invention.

[0044] Wherein: 1, open ring copper conductor; 2, first open end; 3, second open end. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] A certain embodiment of the present invention provides a laminated inductor, which includes a laminated magnetic powder core arranged in layers; the laminated magnetic powder core includes a soft magnetic metal layer and an open ring copper conductor embedded in the soft magnetic metal layer; the two ends of the opening of the open ring copper conductor are respectively a first opening end and a second opening end, and the first opening end and the second opening end expose the soft magnetic metal layer; in two adjacent layers of the laminated magnetic powder core, the openings of the open ring copper conductors are staggered, and the second opening end of one laminated magnetic powder core is connected to the first opening end of another laminated magnetic powder core.

[0047] The laminated inductor provided by the present invention has a simple structure. Through a simple stacking arrangement and in combination with a layered magnetic powder core structure, it can handle large currents (≥200A) while achieving high inductance (≥1000μH). In addition, the preparation method is simple and automated production can be easily realized.

[0048] In some embodiments, the soft magnetic metal layer is composed of any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder, or a combination of at least two of them.

[0049] The present invention makes the composition of the soft magnetic metal layer include any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or alloy metal magnetic powder or a combination of at least two of them. The main and secondary powder combinations can be selected. For example, finer submicron metal magnetic powder is used to fill the gaps between the soft magnetic amorphous magnetic powders, so that the internal distribution of the layered magnetic powder core is more compact and uniform, the magnetic resistance is reduced, the magnetic permeability is improved, and the performance of the laminated inductor is enhanced.

[0050] In some embodiments, the soft magnetic amorphous magnetic powder includes FeSiB amorphous magnetic powder.

[0051] In some embodiments, the nanocrystalline magnetic powder includes FeSiCuBPNd multi-element alloy magnetic powder.

[0052] In some embodiments, the submicron metal magnetic powder includes any one of sendust magnetic powder, iron silicon nickel magnetic powder, iron silicon chromium magnetic powder, iron nickel magnetic powder or carbonyl iron powder, or a combination of at least two thereof.

[0053] Optionally, the submicron metal magnetic powder includes original powder, or flaky magnetic powder obtained by changing the shape through ball milling or belt spinning.

[0054] The appropriate average particle size of the soft magnetic amorphous magnetic powder and the average particle size of the submicron metal magnetic powder can ensure the filling effect.

[0055] In some embodiments, the ratio of the average particle size of the soft magnetic amorphous magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1, for example, it can be 3:1, 4:1 or 5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In some embodiments, the ratio of the average particle size of the nanocrystalline magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1, for example, it can be 3:1, 4:1 or 5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In some embodiments, the average particle size of the soft magnetic amorphous magnetic powder is less than 74 μm.

[0058] In the present invention, the average particle size of the soft magnetic amorphous magnetic powder is 74 μm or less, which means that the soft magnetic amorphous ceramic powder used can pass through a 200-mesh sieve.

[0059] In some embodiments, the average particle size of the nanocrystalline magnetic powder is less than 74 μm.

[0060] In the present invention, the average particle size of the nanocrystalline magnetic powder is 74 μm or less, which means that the nanocrystalline magnetic powder used can pass through a 200-mesh sieve.

[0061] In some embodiments, the total mass of the soft magnetic amorphous magnetic powder and the nanocrystalline magnetic powder, and the mass ratio of the submicron metal magnetic powder is 15:1-20:1, for example, it can be 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In some embodiments, the open ring copper conductor has a width of 0.5 mm to 3 mm and a thickness of 0.2 mm to 1 mm.

[0063] The width of the open ring copper conductor is 0.5 mm-3 mm, for example, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] The thickness of the open ring copper conductor is 0.2 mm-1 mm, for example, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm or 1 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0065] In some embodiments, in any of the open ring-shaped copper conductors, the distance between the first open end and the second open end is 1 to 2 times the width of the open ring-shaped copper conductor. Further preferably, the distance between the first open end and the second open end is 0.5 mm to 6 mm, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or 6 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] In the present invention, the distance between the first opening end and the second opening end refers to the shortest distance between the first opening end and the second opening end.

[0067] In the present invention, the surface of the open annular copper conductor is provided with insulating paint, and the radius can be reasonably set according to the size of the laminated inductor; the insulating paint at the first open end and the second open end is removed to achieve independent conduction at the first open end and the second open end.

[0068] In some embodiments, the first opening end and the second opening end are respectively and independently welded to a conductive joint; the distance of the conductive joint beyond the first opening end or the second opening end does not exceed 1 mm.

[0069] Optionally, the conductive joint is a copper joint.

[0070] In some embodiments, the soft magnetic metal layer further includes a binder.

[0071] Optionally, the binder includes any one of silicone resin, silane coupling agent or polyethylene glycol butyral or a combination of at least two thereof. Typical but non-limiting combinations include a combination of silicone resin and silane coupling agent, a combination of silane coupling agent and polyethylene glycol butyral, a combination of silicone resin and polyethylene glycol butyral, or a combination of silicone resin, silane coupling agent and polyethylene glycol butyral.

[0072] A certain embodiment of the present invention provides a method for preparing the multilayer inductor described in any embodiment, and the preparation method comprises the following steps:

[0073] The open annular copper conductor and the soft magnetic metal powder are assembled to form an integrated inductor; the integrated inductor is heated and cured to expose the first open end and the second open end of the open annular copper conductor to obtain a layered magnetic powder core.

[0074] The required number of layered magnetic powder cores are stacked so that the openings of the open annular copper conductors in two adjacent layers of the layered magnetic powder cores are staggered and the second open end of one layered magnetic powder core is connected to the first open end of another layered magnetic powder core; and then pressure molding and heat treatment are performed in sequence to obtain the laminated inductor.

[0075] In some embodiments, when a desired number of layered magnetic powder cores are stacked, a bonding component, such as a bonding silicone resin, is provided on the contact surfaces of adjacent layered magnetic powder cores.

[0076] In some embodiments, the temperature of the heating and curing treatment does not exceed 220°C, for example, it can be 180°C, 190°C, 200°C, 210°C or 220°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 190°C-210°C.

[0077] In some embodiments, the holding time of the heating and curing treatment is 25 min-30 min, for example, it can be 25 min, 26 min, 27 min, 28 min, 29 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0078] In some embodiments, the molding pressure is 80 MPa-120 MPa, for example, 80 MPa, 90 MPa, 100 MPa, 110 MPa or 120 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0079] In some embodiments, the pressure of the pressurized molding is 580MPa-620MPa, for example, 580MPa, 590MPa, 600MPa, 610MPa or 620MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0080] In some embodiments, the heat treatment temperature is ≤210°C, for example, it can be 180°C, 190°C, 200°C or 210°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0081] In some embodiments, the soft magnetic metal powder includes any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder, or a combination of at least two thereof.

[0082] In some embodiments, the soft magnetic metal powder further includes a binder and a lubricant.

[0083] Optionally, the binder includes any one of silicone resin, silane coupling agent or polyethylene glycol butyral or a combination of at least two thereof. Typical but non-limiting combinations include a combination of silicone resin and silane coupling agent, a combination of silane coupling agent and polyethylene glycol butyral, a combination of silicone resin and polyethylene glycol butyral, or a combination of silicone resin, silane coupling agent and polyethylene glycol butyral.

[0084] Optionally, the lubricant comprises zinc stearate.

[0085] In some embodiments, the soft magnetic metal powder is an insulation-treated soft magnetic metal powder.

[0086] In some embodiments, the insulating treatment is performed using an inorganic acid and / or an insulating oxide.

[0087] In certain embodiments, the inorganic acid includes phosphoric acid and / or chromic acid.

[0088] In certain embodiments, the insulating oxide comprises any one of silicon dioxide, magnesium oxide or aluminum oxide, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of silicon dioxide and magnesium oxide, a combination of magnesium oxide and aluminum oxide, a combination of silicon dioxide and aluminum oxide, or a combination of silicon dioxide, magnesium oxide and aluminum oxide.

[0089] A certain embodiment of the present invention provides an application of the multilayer inductor described in any embodiment, wherein the multilayer inductor is used in a circuit board.

[0090] Example 1

[0091] This embodiment provides a laminated inductor, which includes laminated magnetic powder cores that are laminated. The number of laminated magnetic powder cores is 10.

[0092] The structural schematic diagram of the layered magnetic powder core is as follows Figure 1 As shown, it includes a soft magnetic metal layer and an open ring copper conductor 1 embedded in the soft magnetic metal layer; the two ends of the opening of the open ring copper conductor 1 are respectively a first opening end 2 and a second opening end 3, and the first opening end 2 and the second opening end 3 expose the soft magnetic metal layer; in two adjacent layers of the layered magnetic powder core, the openings of the open ring copper conductor 1 are staggered, and the second opening end 3 of one layered magnetic powder core is connected to the first opening end 2 of another layered magnetic powder core.

[0093] The method for preparing the multilayer inductor in this embodiment includes the following steps:

[0094] (1) Soft magnetic amorphous magnetic powder and submicron metal magnetic powder are mixed in a mass ratio of 18:1 to obtain soft magnetic metal powder; the soft magnetic amorphous magnetic powder is spherical atomized FeSiB amorphous magnetic powder with an average particle size of 60 μm; the submicron metal magnetic powder is atomized iron silicon aluminum magnetic powder with an average particle size of 12 μm.

[0095] (2) The soft magnetic metal powder obtained in step (1) is subjected to insulation treatment and binder treatment respectively, and then uniformly mixed with a lubricant (zinc stearate, 0.3 wt% by mass); the insulation treatment is as follows: 1000 g of the soft magnetic metal powder is treated with 50 g of a phosphoric acid acetone solution (a phosphoric acid solution with a mass of 1 g and a concentration of 35 wt% is dissolved in 5 g of acetone), and then dried in an oven at 80°C for 15 min; the binder treatment is as follows: 48 g of a binder solution (1 g of methyl silicone resin (XJY-8205) is dissolved in 3 g of acetone) is used to treat the dried powder, and then the powder is spread out to dry.

[0096] (3) Preparation of a single-layer laminar magnetic powder core: Using a circular molding mold with a diameter of 12 mm, first lay a 1 mm thick soft magnetic metal powder, then place an open ring copper conductor (outer ring diameter 10 mm, width 1.5 mm, distance between the first open end and the second open end 1.5 mm, thickness 0.8 mm; the first open end and the second open end are welded with a copper joint), and finally lay a 1 mm thick soft magnetic metal powder; then use a press to mold at a pressure of 100 MPa, and demold to obtain an integrated inductor; the integrated inductor is heated and cured at a temperature of 200°C for 28 min to obtain a laminar magnetic powder core; the copper joints of the obtained laminar magnetic powder core are ground to expose the copper joints.

[0097] (4) 10 layers of layered magnetic powder cores are stacked in a press, and silicone resin (SH-968A) is disposed between contact surfaces of two adjacent layers; the openings of the open annular copper conductors in the two adjacent layers of the layered magnetic powder cores are staggered, and the second open end of one layered magnetic powder core is connected to the first open end of another layered magnetic powder core; and then press molding is performed at a pressure of 600 MPa.

[0098] (5) After pressure forming, a mesh bag tunnel heat treatment is used, with the highest heat treatment temperature being 210°C and the time being 25 min. After the heat treatment is completed, the corresponding copper joints are welded to complete the conduction, and the following is obtained: Figure 2 A multilayer inductor with the structure shown.

[0099] Example 2

[0100] This embodiment provides a laminated inductor, which includes laminated magnetic powder cores that are laminated. The number of laminated magnetic powder cores is 10.

[0101] The layered magnetic powder core comprises a soft magnetic metal layer and an open annular copper conductor embedded in the soft magnetic metal layer; the two ends of the opening of the open annular copper conductor are respectively a first opening end and a second opening end, and the first opening end and the second opening end expose the soft magnetic metal layer; in two adjacent layers of the layered magnetic powder core, the openings of the open annular copper conductors are staggered, and the second opening end of one layered magnetic powder core is connected to the first opening end of another layered magnetic powder core.

[0102] The method for preparing the multilayer inductor in this embodiment includes the following steps:

[0103] (1) Soft magnetic amorphous magnetic powder and submicron metal magnetic powder are mixed in a mass ratio of 15:1 to obtain soft magnetic metal powder; the soft magnetic amorphous magnetic powder is spherical atomized FeSiB amorphous magnetic powder with an average particle size of 60 μm; the submicron metal magnetic powder is atomized iron silicon aluminum magnetic powder with an average particle size of 15 μm.

[0104] (2) The soft magnetic metal powder obtained in step (1) is subjected to insulation treatment and binder treatment respectively, and then uniformly mixed with a lubricant (zinc stearate, 0.3 wt% by mass); the insulation treatment is as follows: 1000 g of the soft magnetic metal powder is treated with 50 g of a phosphoric acid acetone solution (a phosphoric acid solution with a mass of 1 g and a concentration of 35 wt% is dissolved in 5 g of acetone), and then dried in an oven at 80°C for 15 min; the binder treatment is as follows: 60 g of a binder solution (1 g of methyl silicone resin (XJY-8205) is dissolved in 4 g of acetone) is used to treat the dried powder, and then the powder is spread out to dry.

[0105] (3) Preparation of a single-layer laminar magnetic powder core: Using a circular molding mold with a diameter of 12 mm, first lay a 1 mm thick soft magnetic metal powder, then place an open ring copper conductor (outer ring diameter 10 mm, width 0.5 mm, distance between the first open end and the second open end 0.5 mm, thickness 0.2 mm; the first open end and the second open end are welded with a copper joint), and finally lay a 1 mm thick soft magnetic metal powder; then use a press to mold at a pressure of 80 MPa, and demold to obtain an integrated inductor; the integrated inductor is heated and cured at a temperature of 190°C for 30 min to obtain a laminar magnetic powder core; the copper joints of the obtained laminar magnetic powder core are ground to expose the copper joints.

[0106] (4) 10 layers of layered magnetic powder cores are stacked in a press, and silicone resin (SH-968A) is disposed between contact surfaces of two adjacent layers; the openings of the open annular copper conductors in the two adjacent layers of the layered magnetic powder cores are staggered, and the second open end of one layered magnetic powder core is connected to the first open end of another layered magnetic powder core; and then press molding is performed at a pressure of 580 MPa.

[0107] (5) After pressure forming, a mesh bag tunnel heat treatment is used, with the highest heat treatment temperature being 210°C and the time being 25 minutes. After the heat treatment is completed, the corresponding copper joints are welded to complete the conduction and obtain a laminated inductor.

[0108] Example 3

[0109] This embodiment provides a laminated inductor, which includes laminated magnetic powder cores that are laminated. The number of laminated magnetic powder cores is 10.

[0110] The layered magnetic powder core comprises a soft magnetic metal layer and an open annular copper conductor embedded in the soft magnetic metal layer; the two ends of the opening of the open annular copper conductor are respectively a first opening end and a second opening end, and the first opening end and the second opening end expose the soft magnetic metal layer; in two adjacent layers of the layered magnetic powder core, the openings of the open annular copper conductors are staggered, and the second opening end of one layered magnetic powder core is connected to the first opening end of another layered magnetic powder core.

[0111] The method for preparing the multilayer inductor in this embodiment includes the following steps:

[0112] (1) Soft magnetic amorphous magnetic powder and submicron metal magnetic powder are mixed in a mass ratio of 20:1 to obtain soft magnetic metal powder; the soft magnetic amorphous magnetic powder is spherical atomized FeSiB amorphous magnetic powder with an average particle size of 60 μm; the submicron metal magnetic powder is atomized iron silicon aluminum magnetic powder with an average particle size of 20 μm.

[0113] (2) The soft magnetic metal powder obtained in step (1) is subjected to insulation treatment and binder treatment respectively, and then uniformly mixed with a lubricant (zinc stearate, 0.3 wt% by mass); the insulation treatment is as follows: 1000 g of the soft magnetic metal powder is treated with 50 g of a phosphoric acid acetone solution (a phosphoric acid solution with a mass of 1 g and a concentration of 35 wt% is dissolved in 5 g of acetone), and then dried in an oven at 80°C for 15 min; the binder treatment is as follows: 60 g of a binder solution (1 g of methyl silicone resin (XJY-8205) is dissolved in 4 g of acetone) is used to treat the dried powder, and then the powder is spread out to dry.

[0114] (3) Preparation of a single-layer laminar magnetic powder core: Using a circular molding mold with a diameter of 12 mm, first lay a 1 mm thick soft magnetic metal powder, then place an open ring copper conductor (outer ring diameter 10 mm, width 3 mm, distance between the first open end and the second open end 6 mm, thickness 1 mm; the first open end and the second open end are welded with a copper joint), and finally lay a 1 mm thick soft magnetic metal powder; then use a press to mold at a pressure of 120 MPa, and demold to obtain an integrated inductor; the integrated inductor is heated and cured at a temperature of 210°C for 25 min to obtain a laminar magnetic powder core; the copper joints of the obtained laminar magnetic powder core are ground to expose the copper joints.

[0115] (4) 10 layers of layered magnetic powder cores are stacked in a press, and silicone resin (SH-968A) is disposed between contact surfaces of two adjacent layers; the openings of the open annular copper conductors in the two adjacent layers of the layered magnetic powder cores are staggered, and the second open end of one layered magnetic powder core is connected to the first open end of another layered magnetic powder core; and then press molding is performed at a pressure of 620 MPa.

[0116] (5) After pressure forming, a mesh bag tunnel heat treatment is used, with the highest heat treatment temperature being 210°C and the time being 25 minutes. After the heat treatment is completed, the corresponding copper joints are welded to complete the conduction and obtain a laminated inductor.

[0117] Performance Characterization

[0118] The magnetic permeability and high current inductance of the laminated inductor obtained in the above embodiment were tested. The magnetic permeability test conditions were TH2816B type LCR tester, frequency 1MHz / level voltage 1V, coil turns 10, and the results are shown in Table 1; the high current (superposition characteristics) inductance test conditions were DPG10-1500B comprehensive reactance tester, maximum voltage 50V, maximum current 300A, and pulse time 500μS.

[0119] Table 1

[0120]

[0121] In summary, the structure of the laminated inductor provided by the present invention is simple. Through a simple stacking arrangement and a layered magnetic powder core structure, it can handle large currents (≥200A) while achieving high inductance (≥1000μH). Moreover, the preparation method is simple and automated production can be easily realized.

[0122] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A multilayer inductor, characterized in that: The laminated inductor comprises a laminated magnetic powder core; The layered magnetic powder core comprises a soft magnetic metal layer and an open annular copper conductor embedded in the soft magnetic metal layer; The two ends of the opening of the open annular copper conductor are respectively a first opening end and a second opening end, and the first opening end and the second opening end expose the soft magnetic metal layer; In two adjacent layers of the laminar magnetic powder cores, the openings of the open annular copper conductors are staggered, and the second opening end of one laminar magnetic powder core is connected to the first opening end of the other laminar magnetic powder core.

2. The multilayer inductor according to claim 1, characterized in that: The soft magnetic metal layer comprises any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder or a combination of at least two thereof; Preferably, the soft magnetic amorphous magnetic powder comprises FeSiB amorphous magnetic powder; Preferably, the nanocrystalline magnetic powder comprises FeSiCuBPNd multi-element alloy magnetic powder; Preferably, the submicron metal magnetic powder includes any one of sendust magnetic powder, iron silicon nickel magnetic powder, iron silicon chromium magnetic powder, iron nickel magnetic powder or carbonyl iron powder, or a combination of at least two thereof.

3. The multilayer inductor according to claim 2, characterized in that: The ratio of the average particle size of the soft magnetic amorphous magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1; Preferably, the ratio of the average particle size of the nanocrystalline magnetic powder to the average particle size of the submicron metal magnetic powder is 3:1-5:1; Preferably, the average particle size of the soft magnetic amorphous magnetic powder is less than 74 μm; Preferably, the average particle size of the nanocrystalline magnetic powder is less than 74 μm; Preferably, the mass ratio of the total mass of the soft magnetic amorphous magnetic powder and the nanocrystalline magnetic powder to the mass ratio of the submicron metal magnetic powder is 15:1-20:

1.

4. The multilayer inductor according to any one of claims 1 to 3, characterized in that: The open annular copper conductor has a width of 0.5 mm to 3 mm and a thickness of 0.2 mm to 1 mm; Preferably, in any of the open annular copper conductors, a distance between the first open end and the second open end is 0.5 mm-6 mm.

5. A method for preparing a multilayer inductor according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: Assembling an open annular copper conductor and soft magnetic metal powder to form an integrated inductor; subjecting the obtained integrated inductor to a heating and curing treatment and a simple processing to expose a first open lower end and a second open upper end of the open annular copper conductor to obtain a layered magnetic powder core; The required number of layered magnetic powder cores are stacked so that the openings of the open annular copper conductors in two adjacent layers of the layered magnetic powder cores are staggered, and the second opening upper end of one layered magnetic powder core is connected to the first opening lower end of another layered magnetic powder core; and then pressure molding and heat treatment are performed in sequence to obtain the laminated inductor.

6. The preparation method according to claim 5, characterized in that: The temperature of the heating and curing treatment does not exceed 220°C, preferably 190°C-210°C; Preferably, the heat preservation time of the heating and curing treatment is 25min-30min.

7. The preparation method according to claim 5 or 6, characterized in that: The molding pressure is 80MPa-120MPa; Preferably, the pressure of the pressurizing molding is 580MPa-620MPa; Preferably, the temperature of the heat treatment is ≤210°C.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The soft magnetic metal powder includes any one of soft magnetic amorphous magnetic powder, nanocrystalline magnetic powder or submicron metal magnetic powder, or a combination of at least two thereof; Preferably, the soft magnetic metal powder is soft magnetic metal powder that has been subjected to insulation treatment.

9. The preparation method according to claim 8, characterized in that: The insulation treatment is carried out using inorganic acid and / or insulating oxide; Preferably, the inorganic acid comprises phosphoric acid and / or chromic acid; Preferably, the insulating oxide includes any one of silicon dioxide, magnesium oxide or aluminum oxide, or a combination of at least two thereof.

10. An application of the multilayer inductor according to any one of claims 1 to 4, characterized in that: The multilayer inductor is used for a circuit board.

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