Internally Embedded Copper Plate-Type Soft Magnetic Powder Core Inductor, Preparation Method Therefor, and Use Thereof

Abstract

The present application relates to an internally embedded copper plate-type soft magnetic powder core inductor, a preparation method therefor, and a use thereof. The internally embedded copper plate-type soft magnetic powder core inductor comprises a copper plate, a surface of the copper plate is covered with a soft magnetic material, and an interfacing area of the soft magnetic material and the copper plate includes an insulating resin material. The internally embedded copper plate-type soft magnetic powder core inductor possesses high density, high magnetic core magnetic permeability, high inductance, high saturated magnetic flux density, low volume, and low magnetic flux leakage, if said powder core inductor is used to replace a ferrite inductor of a same inductance for a low voltage DC/DC converter circuit, the same or greater efficiency can be achieved, and inductor volume can be reduced by at least half; the withstand voltage of the internally embedded copper plate type soft magnetic powder core inductor can reach over 15V, and the preparation method for said inductor is simple, possessing high production efficiency and suitable for large-scale automated production.

Claims

1. A copper sheet-embedded soft magnetic powder core inductor, comprising: a copper sheet, a soft magnetic material covered on a surface of the copper sheet, and an insulating resin material contained on an interface between the copper sheet and the soft magnetic material.

2. The copper sheet-embedded soft magnetic powder core inductor according to claim 1, wherein the soft magnetic material in the copper sheet-embedded soft magnetic powder core inductor has a density of 5.5-6.5 g/cm.sup.3.

3. The copper sheet-embedded soft magnetic powder core inductor according to claim 1, wherein the soft magnetic material is obtained through soft magnetic metal powder subjected to press molding.

4. A method for preparing the copper sheet-embedded soft magnetic powder core inductor according to claim 1, the method comprising the following steps: (a) coating an insulating resin material on a surface of a copper sheet, baking and curing; and (b) placing the copper sheet coated with the insulating resin material and obtained in step (a) in soft magnetic metal powder, press molding, and annealing in an inert atmosphere to obtain the copper sheet embedded soft magnetic powder core inductor.

5. The method according to claim 4, wherein the soft magnetic metal powder in step (b) has an average particle size of 2-25 μm.

6. The method according to claim 4, wherein the annealing in step (b) is carried out at a temperature of 550-700° C.

7. The method according to claim 4, wherein the insulating resin material in step (a) comprises an organosilicon resin material.

8. The method according to claim 4, wherein the press molding in step (b) is carried out at a pressure of 12-18 T/cm.sup.2.

9. The method according to claim 4, wherein the inert atmosphere is nitrogen.

10. A method for preparing the copper sheet-embedded soft magnetic powder core inductor according to claim 1, the method comprising the following steps: (a) coating an organosilicon resin material on a surface of a copper sheet, baking and curing; and (b) placing the copper sheet coated with the organosilicon resin material and obtained in step (a) in soft magnetic metal powder with an average particle size of 10 μm, press molding at a pressure of 12-18 T/cm.sup.2 to obtain a molded body, and placing the molded body in an annealing furnace for annealing at 550-700° C. in an inert atmosphere for 1-3 hours to obtain the copper sheet-embedded soft magnetic powder core inductor.

11. A low-voltage DC/DC converter circuit comprising the copper sheet-embedded soft magnetic powder core inductor according to claim 1.

12. The copper sheet-embedded soft magnetic powder core inductor according to claim 3, wherein the soft magnetic metal powder comprises any one selected from the group consisting of iron powder, iron-silicon powder, iron-silicon-aluminium powder, iron-nickel powder, iron-nickel-molybdenum powder, and a combination of at least two selected therefrom.

13. The copper sheet-embedded soft magnetic powder core inductor according to claim 1, wherein the insulating resin material comprises an organosilicon resin material.

14. The method according to claim 4, wherein the annealing in step (b) is carried out for 1-3 hours.

15. The method according to claim 4, wherein the soft magnetic metal powder in step (b) comprises any one selected from the group consisting of iron powder, iron-silicon powder, iron-silicon-aluminium powder, iron-nickel powder, iron-nickel-molybdenum powder, and a combination of at least two selected therefrom.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0046] FIG. 1 is a structure diagram of the copper sheet-embedded soft magnetic powder core inductor of the present application.

DETAILED DESCRIPTION

[0047] The technical solutions of the present application are further described below through the detailed description. Those skilled in the art are to understand that examples described herein are merely used for a better understanding of the present application and are not to be construed as specific limitations to the present application.

[0048] A structure diagram of the copper sheet-embedded soft magnetic powder core inductor is shown in FIG. 1. As can be seen from FIG. 1, the copper sheet-embedded soft magnetic powder core inductor includes a copper sheet, a soft magnetic material covered on a surface of the copper sheet, and an insulating resin material contained on an interface between the copper sheet and the soft magnetic material. The soft magnetic material is symmetrically distributed on two sides of the copper sheet, and two ends of the copper sheet are not covered by the soft magnetic material. As shown in FIG. 1, regions of the copper sheet that are not covered by the soft magnetic material are bent as shown in FIG. 1.

Example 1

[0049] A method for preparing a copper sheet-embedded soft magnetic powder core inductor includes the following steps:

[0050] (1) organosilicon resin SILRES® REN 60 was coated evenly on a surface of a copper sheet with a thickness of 0.3 mm and a width of 2.5 mm and baked until it was cured; and

[0051] (2) the copper sheet treated in step (1) was embedded into magnetic iron-silicon-aluminium powder with an average particle size of 15 μm and press molded at a pressure of 16 T/cm.sup.2 so that there was obtained a molded body with a length of 14 mm, a width of 5 mm, and a height of 2 mm; then, the molded body was placed in an annealing furnace and annealed at 680° C. for 120 minutes in a nitrogen atmosphere so that the copper sheet-embedded soft magnetic powder core inductor was obtained.

[0052] The size of the molded body includes the size of the soft magnetic material and the size of the copper sheet embedded in the soft magnetic material.

Example 2

[0053] A method for preparing a copper sheet-embedded soft magnetic powder core inductor includes the following steps:

[0054] (1) organosilicon resin SILRES® REN 60 was coated evenly on a surface of a copper sheet with a thickness of 0.25 mm and a width of 2.5 mm and baked until it was cured; and

[0055] (2) the copper sheet treated in step (1) was embedded into magnetic iron-silicon-aluminium powder with an average particle size of 15 μm and press molded at a pressure of 12 T/cm.sup.2 so that there was obtained a molded body with a length of 14 mm, a width of 5 mm, and a height of 2 mm; then, the molded body was placed in an annealing furnace and annealed at 680° C. for 120 minutes in a nitrogen atmosphere so that the copper sheet-embedded soft magnetic powder core inductor was obtained.

Example 3

[0056] A method for preparing a copper sheet-embedded soft magnetic powder core inductor includes the following steps:

[0057] (1) organosilicon resin SILRES® REN 60 was coated evenly on a surface of a copper sheet with a thickness of 0.3 mm and a width of 2.7 mm and baked until it was cured; and

[0058] (2) the copper sheet treated in step (1) was embedded into magnetic iron-silicon-aluminium powder with an average particle size of 10 μm and press molded at a pressure of 18 T/cm.sup.2 so that there was obtained a molded body with a length of 14 mm, a width of 5 mm, and a height of 2 mm; then, the molded body was placed in an annealing furnace and annealed at 680° C. for 120 minutes in a nitrogen atmosphere so that the copper sheet-embedded soft magnetic powder core inductor was obtained.

Example 4

[0059] This example differs from Example 1 in that the annealing temperature was changed from 680° C. to 550° C., and other conditions were exactly the same as those of Example 1.

Example 5

[0060] This example differs from Example 1 in that the annealing temperature was changed from 680° C. to 450° C., and other conditions were exactly the same as those of Example 1.

Example 6

[0061] This example differs from Example 1 in that the annealing temperature was changed from 680° C. to 800° C., and other conditions were exactly the same as those of Example 1.

Example 7

[0062] This example differs from Example 1 in that the average particle size of the magnetic iron-silicon-aluminium powder in step (2) was changed from 10 μm to 2 μm, and other conditions were exactly the same as those of Example 1.

Example 8

[0063] This example differs from Example 1 in that the average particle size of the magnetic iron-silicon-aluminium powder in step (2) was changed from 10 μm to 20 μm, and other conditions were exactly the same as those of Example 1.

Example 9

[0064] This example differs from Example 1 in that the magnetic iron-silicon-aluminium powder in step (2) was replaced with iron-nickel powder with the same average particle size, and other conditions were exactly the same as those of Example 1.

Example 10

[0065] This example differs from Example 1 in that the magnetic iron-silicon-aluminium powder in step (2) was replaced with iron-nickel-molybdenum powder with the same average particle size, and other conditions were exactly the same as those of Example 1.

Comparative Example 1

[0066] This comparative example uses a ferrite inductor with the same inductance as the copper sheet-embedded soft magnetic powder core inductor in Example 1. The size of the ferrite inductor is 14 mm in length, 5 mm in width, and 8 mm in height. The ferrite inductor was prepared by the following method: two pieces of ferrite with a groove of 14 mm×5 mm×4 mm were made, where the groove has a depth of 1.7 mm, the two pieces of ferrite were buckled up and down, and a copper sheet was penetrated through the groove and bent so that the required ferrite inductor was obtained.

[0067] Performance Test

[0068] The density, volume and inductance of each of the copper sheet-embedded soft magnetic powder core inductors prepared in Examples 1 to 10 and the ferrite inductor in Comparative Example 1 were tested. Efficiency was tested when they were applied to low-voltage DC/DC converter circuits. Test results are shown in Table 1. The volume of the copper sheet-embedded soft magnetic powder core inductor refers to the sum of the volume of the molded body and the volume of the copper sheet uncovered by the soft magnetic material.

[0069] Test conditions were a frequency of 700 kHz, a current of 40 A, and a voltage of 1 V when they were applied to the low-voltage DC/DC converter circuits.

[0070] The insulation withstand voltages of the copper sheet-embedded soft magnetic powder core inductors prepared in Examples 1 to 10 and the ferrite inductor in Comparative Example 1 were tested. Test results are shown in Table 1.

TABLE-US-00001 TABLE 1 Insulation Density inductance Volume Efficiency Resistance (g/cm.sup.3) (nH) (mm.sup.3) (%) (kΩ, 15 V) Example 1 5.7 138 146 87.2 50 Example 2 5.62 126 145 86.5 51 Example 3 5.73 135 146 87.3 52 Example 4 5.71 138 146 87.1 55 Example 5 5.7 137 146 86.5 50 Example 6 5.71 132 146 85.1 35 Example 7 5.51 122 146 86.5 51 Example 8 5.75 142 146 87.1 51 Example 9 6.3 125 146 86.5 45 Example 10 6.5 127 146 86.3 48 Comparative 4.5 138 584 87.1 70 Example 1

[0071] It can be seen from the above table that the density of the copper sheet-embedded soft magnetic powder core inductor of the present application ranges from 5.5 g/cm.sup.3 to 6.5 g/cm.sup.3 and is significantly higher than that of the ferrite inductor in Comparative Example 1. It can be seen from the comparison of Example 1 and Comparative Example 1 that under the same inductance, the volume of the copper sheet-embedded soft magnetic powder core inductor in Example 1 is about a quarter of the volume of the ferrite inductor in Comparative Example 1. Moreover, the copper sheet-embedded soft magnetic powder core inductor in Example 1 has higher efficiency than the ferrite inductor in Comparative Example 1 when they are applied to the low-voltage DC/DC converter circuits.

[0072] It can be seen from the comparison of Examples 1 and 4 to 6 that when the annealing temperature is 550-680° C., the obtained copper sheet-embedded soft magnetic powder core inductor has higher efficiency when applied to the low-voltage DC/DC converter circuits.

[0073] The applicant has stated that the above examples are only specific embodiments of the present application, and the protection scope of the present application is not limited thereto.