Magnetic element

Abstract

A magnetic element comprises a magnetic core, at least one partition plate and at least two coils. The magnetic core comprises an inner column and at least two outer columns. The at least two coils and the at least one partition plate are mutually stacked and directly sleeved on the inner column. And each coil is formed by winding at least three layers of wires coated with insulating tapes in a staggered manner.

Description

Technical Field

[0001] The invention relates to a magnetic element, in particular to a magnetic element capable of reducing the thermal stress of a magnetic core. Background Art

[0002] Due to the demand for fast charging of electric vehicles, the operating power is getting higher and higher, which makes the heat generated by the electronic components themselves higher and higher. The magnetic components of the on-board charger (OBC), such as the transformer, will generate heat due to loss during operation, and the uneven heat will cause additional thermal stress on the magnetic core of the transformer, which will increase the core loss of the transformer. Under continuous circulation, the heat will not converge, resulting in excessive temperature and loss, and in severe cases, it will cause irreversible damage and rupture of the magnetic core. Summary of the invention

[0003] The object of the present invention is to provide a magnetic element capable of reducing the thermal stress of the magnetic core, so as to solve the above-mentioned problem.

[0004] According to one embodiment, the magnetic element of the present invention comprises a magnetic core, at least one coil and a thermally conductive filler. The magnetic core comprises an inner column, at least two outer columns and at least one non-joining area. At least one coil is wound around the inner column or the at least two outer columns. The thermally conductive filler covers a portion of the magnetic core. At least a portion of at least one non-joining area is not covered by the thermally conductive filler.

[0005] According to another embodiment, the magnetic element of the present invention comprises a magnetic core, at least one coil and a thermally conductive filler. The magnetic core comprises an inner column, at least two outer columns and at least one non-joining area. The at least one non-joining area is located at the at least two outer columns. At least one coil is wound around the inner column or the at least two outer columns. The thermally conductive filler covers a portion of the magnetic core and at least one non-joining area located at the at least two outer columns.

[0006] According to another embodiment, the magnetic element of the present invention comprises a magnetic core, a bracket, at least one coil and a thermally conductive filler. The magnetic core comprises an inner column, at least two outer columns and a plurality of non-bonding areas. The plurality of non-bonding areas are located at the inner column and at least two outer columns. The bracket is sleeved on the inner column. An upper surface of the bracket is bonded to an inner plate surface of the magnetic core. At least one coil is disposed on the bracket. The thermally conductive filler covers a portion of the magnetic core and does not cover the plurality of non-bonding areas.

[0007] According to another embodiment, the magnetic element of the present invention comprises a magnetic core, at least one partition and at least two coils. The magnetic core comprises an inner column and at least two outer columns. The at least two coils and the at least one partition are stacked on each other and directly sleeved on the inner column. Each coil is wound by a wire with at least three layers of insulation tape staggeredly wrapped.

[0008] In summary, in one embodiment, at least one non-joining area may be located at the inner column or at least two outer columns, and at least a portion of at least one non-joining area may not be covered by a thermally conductive filler. Thus, the inner column or at least two outer columns with a non-joining area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. In addition, in another embodiment, at least one non-joining area may be located at at least two outer columns, and a thermally conductive filler may cover at least one non-joining area. Similarly, at least two outer columns with a non-joining area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. In another embodiment, the coil and the partition may be stacked on each other and directly sleeved on the inner column of the magnetic core, so that the coil does not need to be wound around the bracket, and the insulation and heat dissipation effect between the primary coil and the secondary coil, and between the coil and the magnetic core can be improved. Thus, the magnetic element will not be limited by the size and space of the bracket, and the partition can be in close contact with the coil, or the lead cover structure can be extended between the two coils to fix and minimize the distance and gap between the partition and the coil, so as to miniaturize the size of the magnetic element.

[0009] The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a cross-sectional view of a magnetic element according to an embodiment of the present invention.

[0011] Figure 2 FIG. 4 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

[0012] Figure 3 for Figure 2 Exploded view of the partition, lead cover and two coils.

[0013] Figure 4 Schematic diagram of four partitions with different shapes.

[0014] Figure 5 Schematic diagram of a conductor with three layers of insulation tape staggered wrapped.

[0015] Figure 6 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

[0016] Figure 7 for Figure 6 Cross-sectional view of the magnetic component in FIG.

[0017] Figure 8 for Figure 6 Another cross-sectional view of the magnetic element in FIG.

[0018] Fig. 9 for Figure 7 A three-dimensional view of the bracket in FIG.

[0019] Fig.10 for Fig. 9 Top view of the bracket in .

[0020] Fig.11 FIG. 4 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

[0021] Fig.12 FIG. 4 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

[0022] Fig.13 FIG. 4 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

[0023] Fig.14 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

[0024] Fig.15 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

[0025] The reference numerals are as follows:

[0026] 1,1',1",1"',1"",3: Magnetic components

[0027] 10,30: Magnetic core

[0028] 10a: First core

[0029] 10b: Second core

[0030] 10c: The third core

[0031] 12: Coil

[0032] 12a: Primary coil

[0033] 12b: Secondary coil

[0034] 14: Thermally conductive filler

[0035] 16: Shell

[0036] 18: Partition

[0037] 18a: Gap

[0038] 18b,19a: Wire duct

[0039] 19: Lead cover

[0040] 20,20': Bracket

[0041] 22: Heat sink

[0042] 100:Inner column

[0043] 102: Outer column

[0044] 104, 104a, 104b: non-joining area

[0045] 106: Junction area

[0046] 108a, 108b: Side wall

[0047] 110,112: Inner panel surface

[0048] 120: Insulation tape

[0049] 122: Wire

[0050] 200: Boss

[0051] 202,202a,202b: Holes

[0052] 202c: Boundary

[0053] 204:On the board

[0054] 206: Lower board

[0055] 208: Upper surface

[0056] 210: Lower surface

[0057] 300: Board

[0058] 302: V-groove

[0059] 1000: Suspension

[0060] H1,H2,H3: Height

[0061] L,X1,X2: Length

[0062] R: radians

[0063] S1: Top surface

[0064] S2: Side

[0065] W1,W2: Width DETAILED DESCRIPTION

[0066] See also Figure 1 , Figure 1 is a cross-sectional view of a magnetic element 1 according to an embodiment of the present invention.

[0067] The magnetic element 1 of the present invention may be a reactor, a transformer, an inductor or other magnetic elements. Figure 1As shown, the magnetic element 1 includes a magnetic core 10, at least one coil 12 and a thermal conductive filler 14. The magnetic core 10 includes an inner column 100, at least two outer columns 102, at least one non-joining area 104 and at least one joining area 106. In this embodiment, the magnetic core 10 may include a first core 10a and a second core 10b, wherein the inner column 100 may be a middle column extending from the first core 10a, and the two outer columns 102 may be side columns extending from the periphery of the first core 10a. Therefore, in this embodiment, the first core 10a may be an E-type magnetic core, a PQ-type magnetic core, a T-type magnetic core or an F-type magnetic core, and the second core 10b may be an I-type magnetic core, a UU-type magnetic core, a U-type magnetic core, a UI-type magnetic core, an EI-type magnetic core or an F-type magnetic core. However, the types of the first core 10a and the second core 10b may be determined according to actual applications, and the present invention is not limited to the embodiments shown in the figures.

[0068] At least one coil 12 can be wound around the inner column 100 or at least two outer columns 102. In the present embodiment, the coil 12 can be wound around the inner column 100, but is not limited thereto. In another embodiment, the coil 12 can also be wound around at least two outer columns 102. In the present embodiment, the second core 10b is disposed on the first core 10a, and the inner column 100 is joined to the second core 10b to form a joining area 106. In addition, the second core 10b is not joined to the two outer columns 102, so that two non-joining areas 104 are located between the two outer columns 102 and the second core 10b. The type of the coil 12 can be round wire, rectangular wire or multi-strand wire.

[0069] In this embodiment, the magnetic core 10 may be disposed in the housing 16, and the thermal conductive filler 14 may be filled in the housing 16, so that the thermal conductive filler 14 covers a portion of the magnetic core 10. At this time, at least a portion of at least one non-joining area 104 is not covered by the thermal conductive filler 14. Figure 1 As shown, the two non-joining areas 104 and the joining area 106 are not covered by the thermal conductive filler 14. Therefore, the two outer columns 102 with the two non-joining areas 104 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10. Taking the inductor with a power of 6.6KW as an example, the maximum thermal stress can be reduced from 68Mpa to 27Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 154°C to 96°C. It should be noted that an inner plate surface 110 of the magnetic core 10 may not be covered by the thermal conductive filler 14.

[0070] In the present embodiment, the thermal conductivity of the thermally conductive filler 14 may be greater than 0.3 W / mk, and the material of the thermally conductive filler 14 may include epoxy, silicone, polyurethane (PU), phenolic resins, thermoplastic polyethylene terephthalate (PET), polyamide (PA), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.

[0071] See also Figures 2 to 5 , Figure 2 is a cross-sectional view of a magnetic element 1 according to another embodiment of the present invention, Figure 3 for Figure 2 An exploded view of the partition 18, the lead cover 19 and the two coils 12, Figure 4 is a schematic diagram of four partitions 18 having different shapes, Figure 5 It is a schematic diagram of the conductor 122 staggeredly wrapped with three layers of insulating tape 120. In some embodiments, the material of the partition 18 has magnetic conductivity and electrical insulation, or thermal conductivity and electrical insulation. For example, the partition 18 can be formed by injection molding after mixing magnetic powder and plastic, or a magnetic body (such as Ferrite), or a material with high thermal conductivity and electrical insulation (such as ceramic material). In this embodiment, at least one coil 12 may include a primary coil 12a and a secondary coil 12b, and the cross-section thereof may be circular, elliptical or rectangular, wherein the rectangle can effectively improve the volume utilization. As Figure 4As shown, the partition 18 may include an annular structure (e.g., circular, elliptical, semicircular or semi-elliptical) disposed between the primary coil 12a and the secondary coil 12b. Thus, leakage inductance (Lk) and power density (power density) may be increased. In addition, the magnetic element 1 may further include a lead cover 19, which is directly sleeved on the inner column 100 of the magnetic core 10 and stacked above the partition 18 and the two coils 12, for leading the end wires of the coils 12 out of the magnetic core 10 through the wire groove 19a of the lead cover 19. In this embodiment, the lead cover 19 is an electrically insulating material. In this embodiment, the partition 18 also includes a wire groove 18b corresponding to the wire groove 19a of the lead cover 19. When the partition 18, the lead cover 19 and the two coils 12 are stacked on each other and directly sleeved on the inner column 100 of the magnetic core 10, the end wires of the coils 12 will be led out of the magnetic core 10 through the wire groove 19a of the lead cover 19 and the wire groove 18b of the partition 18.

[0072] like Figure 2 and Figure 3As shown, the magnetic element 1 may include a magnetic core 10, at least one partition 18 and at least two coils 12, wherein the at least two coils 12 and the at least one partition 18 are stacked on each other and directly sleeved on the inner column 100. In this embodiment, the magnetic element 1 may include a partition 18, a lead cover 19 and two coils 12 stacked on each other. The coil 12 does not need to be wound around the bracket. After the coil 12 is wound into an air coil, the coil 12 and the partition 18 can be stacked on each other and directly sleeved on the inner column 100 of the magnetic core 10. In this embodiment, the winding structure of the coil 12 is composed of two layers of outer wires (outer-outer winding), which is different from the winding structure of the inner wires (inner-outer winding), and has better flatness. As a result, the magnetic element 1 will not be limited by the size and space of the bracket, and the partition 18 can be in close contact with the coil 12, or the lead cover 19 structure can be used to extend between the two coils 12 to fix and minimize the spacing and gap between the partition 18 and the coil 12, so as to miniaturize the size of the magnetic element 1. Since the space and size of the magnetic element 1 can be miniaturized, the heat dissipation path can be shortened and there is no (winding) bracket and lead cover of the structure covering the inner column, so as to obtain a good heat dissipation effect. In this embodiment, the partition 18 has a gap 18a. When the partition 18 and the two coils 12 are stacked, the thermally conductive filler 14 can be filled in the gap 18a between the relatively overlapping surfaces of the two coils 12 and the relative surfaces between the inner column and the two coils 12. The thermally conductive filler 14 can also cover the outward surfaces of the two coils 12 and the partition 18, so that the heat dissipation surface of the two coils 12 is increased, thereby obtaining a good heat dissipation effect. In some embodiments, the thermally conductive filler 14 is not included. In the absence of a bracket with a partition and a coil, the airflow can more easily enter the partition 18, the lead cover 19 and the two coils 12, and a good heat dissipation effect can be obtained. In some embodiments, in order to maintain the same insulation between the two coils 12 and between the two coils 12 and the magnetic core 10 without a bracket, the two coils 12 are staggered and covered with at least three layers of insulating tape 120 (such as Figure 5 The single insulating tape 120 is staggered from the first layer to at least the second and third layers, and the staggered overlap ratio (W2 / W1) is greater than 67%, where W1 is the width of the single insulating tape 120, and W2 is the overlap width. The insulating tape 120 can be made of PI insulating film (Polyimide Film). The single wire 122 or multiple wires 122 are preferably enameled wires covered with an insulating layer.

[0073] See also Figures 6 to 10 , Figure 6 is a three-dimensional diagram of a magnetic element 1' according to another embodiment of the present invention, Figure 7 for Figure 6 A cross-sectional view of a magnetic element 1' in FIG. Figure 8 for Figure 6 Another cross-sectional view of the magnetic element 1' in FIG. Fig. 9 for Figure 7 A perspective view of the bracket 20 in FIG. Fig.10 for Fig. 9 A top view of the bracket 20 in FIG.

[0074] The main difference between the magnetic element 1' and the above-mentioned magnetic element 1 is that the magnetic element 1' further includes a bracket 20, and the inner column 100 further includes a suspension part 1000. Figures 6 to 9 As shown. In the present embodiment, the proportion T of the suspension portion 1000 to the inner column 100 may be 50% or 2% to 95%. Further, the inner column 100 has a length X1, and the suspension portion 1000 has a length X2, then the proportion T of the suspension portion 1000 to the inner column 100 is X2 / X1. The bracket 20 is sleeved on the inner column 100, and at least one coil 12 is disposed on the bracket 20. Therefore, the coil 12 is still wound around the inner column 100. In the present embodiment, the inner side of the bracket 20 has a boss 200, and the suspension portion 1000 of the inner column 100 is supported on the boss 200, so that the suspension portion 1000 is located between the first core body 10a and the second core body 10b. In the present embodiment, the boss 200 may extend from the outer side of the inner column 100 toward the inner side to support the suspension portion 1000.

[0075] In this embodiment, the first core 10a and the second core 10b are joined to each other at two outer columns 102 to form two joining areas 106. In addition, the second core 10b is not joined to the suspension part 1000, and the suspension part 1000 is supported on the boss 200, so that the two non-joining areas 104a and 104b are located on opposite sides of the suspension part 1000. After the thermal conductive filler 14 is filled in the housing 16, one of the two non-joining areas 104a and 104b is not (completely) covered by the thermal conductive filler 14. Figure 7 As shown, the non-joining area 104a and the two joining areas 106 below the suspension portion 1000 are both covered by the thermal conductive filler 14, and the non-joining area 104b above the suspension portion 1000 is not covered by the thermal conductive filler 14. Therefore, the inner column 100 having the non-joining area 104b can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby preventing the increase of the loss of the magnetic core 10.

[0076] In this embodiment, the height H1 of the thermally conductive filler 14 can be less than or equal to the height H2 of the bracket 20, so that the thermally conductive filler 14 does not contact the bottom surface of the second core 10b. Therefore, the thermal expansion stress of the thermally conductive filler 14 can be greatly reduced, and the second core 10b and the inner column 100 will not interact due to the higher thermal stress of the thermally conductive filler 14, thereby reducing the temperature difference (or maximum temperature) of the magnetic core 10. As a result, the thermal stress of the magnetic core 10 can be reduced, thereby avoiding an increase in the loss of the magnetic core 10.

[0077] like Figure 7 As shown in Fig. 9 , at least one hole 202 can be formed in the bracket 20 so that the heat-conducting filler 14 contacts the inner side of at least one coil 12, and the contact area between the heat-conducting filler 14 and the inner column 100 is increased, thereby increasing the heat dissipation path, effectively reducing the temperature difference (or the maximum temperature), and reducing the additional loss caused by heat. In this embodiment, one of the at least one hole 202 can extend from an upper plate 204 of the bracket 20 towards a lower plate 206 of the bracket 20, and the boundary of one of the at least one hole 202 can overlap between the upper plate 204 and the lower plate 206 of the bracket 20. As shown in Fig. 9 , the at least one hole 202 includes two holes 202a and two holes 202b. The two holes 202b can extend from the upper plate 204 of the bracket 20 towards the lower plate 206 of the bracket 20, and the boundary 202c of each hole 202b can overlap between the upper plate 204 and the lower plate 206, as shown in Fig. 9 As shown in Fig.10 . Thus, the heat-conducting filler 14 can more easily flow into the bracket 20 to conduct more heat from the coil 12. In addition, the bracket 20 (injection molding) can be manufactured with fewer molds to reduce costs.

[0078] For example, when the magnetic component 1' is an inductor or a transformer with a power of 5.5 KW, and the proportion of the suspension part 1000 in the inner column 100 is 30%, the maximum thermal stress can be reduced from 52 Mpa to 28.6 Mpa, and the highest temperature of the magnetic core 10 can be reduced from 110 °C to 87.106 °C. Although the temperature of the suspension part 1000 is 128.45 °C, the suspension part 1000 is a simple column shape and will not crack. If the winding position of the coil with a large cross-sectional area is further considered, the proportion of the suspension part 1000 in the inner column 100 and the winding position of the coil with a large wire diameter are as follows. It should be noted that at least one coil 12 can include a primary coil 12a and a secondary coil 12b, where the position of the secondary coil 12b corresponds to the suspension part 1000, and the position of the primary coil 12a corresponds to the inner column 100 of the first core body 10a. The primary coil 12a has a cross-sectional area D1, and the secondary coil 12b has a cross-sectional area D2. If the cross-sectional area D1 of the primary coil 12a is larger than the cross-sectional area D2 of the secondary coil 12b, the operating temperature of the primary coil 12a is higher than the operating temperature of the secondary coil 12b, and the proportion T of the suspension part 1000 in the inner column 100 can satisfy 50% < T ≤ 95%. If the cross-sectional area D1 of the primary coil 12a is smaller than the cross-sectional area D2 of the secondary coil 12b, the operating temperature of the secondary coil 12b is higher than the operating temperature of the primary coil 12a, and the proportion T of the suspension part 1000 in the inner column 100 can satisfy 2% ≤ T < 50%.

[0079] As shown in Figure 6 As shown in Figure 7As shown, the magnetic element 1' may further include a heat sink 22 disposed on the magnetic core 10, wherein the heat sink 22 contacts a top surface S1 and a side surface S2 of the magnetic core 10. In the present embodiment, the magnetic element 1' may include two heat sinks 22 disposed on two opposite sides of the magnetic core 10, but is not limited thereto. In the present embodiment, the heat sink 22 may be L-shaped, and the length L of the portion of the heat sink 22 contacting the side surface S2 of the magnetic core 10 may be less than the height H3 of the magnetic core 10. Thus, even if there is a tolerance in the height of the magnetic core 10, the heat sink 22 can maintain contact with the top surface S1 of the magnetic core 10 without a gap, thereby enhancing the heat dissipation effect. In addition, since there are two heat sinks 22 attached to the top surface S1 and the side surface S2, the heat sink 22 can be manufactured by a process with lower cost and higher tolerance. The heat sink 22 with an L shape does not limit the application and can also be applied in other embodiments.

[0080] In this embodiment, the thermal conductive filler 14 can cover a portion of the heat sink 22, so that the heat sink 22 can conduct heat to the bottom. In addition, the heat sink 22 can be attached to the magnetic core 10 through a colloid with a Shore D or Shore A hardness (Shore Dor Shore A hardness) less than 80 to reduce the temperature difference (or maximum temperature) of the magnetic core 10 and reduce thermal stress. For example, if the Shore D hardness is greater than 80, the corresponding maximum temperature of the magnetic core 10 can be 59.3°C; if the Shore D hardness is less than 80, the corresponding maximum temperature of the magnetic core 10 can be 50.6°C.

[0081] See also Fig.11 , Fig.11 is a cross-sectional view of a magnetic element 1" according to another embodiment of the present invention.

[0082] The main difference between the magnetic element 1 ″ and the above-mentioned magnetic element 1 is that, in addition to the first core 10a and the second core 10b, the magnetic element 1 ″ also includes a third core 10c. Fig.11 As shown, the first core 10a and the second core 10b are arranged side by side and joined with the third core 10c at two outer columns 102 to form a joining area 106. In addition, the two adjacent side walls 108a and 108b of the first core 10a and the second core 10b are not joined to each other, so that the non-joining area 104a is located between the two adjacent side walls 108a and 108b of the first core 10a and the second core 10b. In this embodiment, the two adjacent side walls 108a and 108b form a part of the inner column 100. The inner column 100 of the third core 10c is arranged opposite to the inner columns 100 of the first core 10a and the second core 10b and is not joined, thereby forming another non-joining area 104b. The inner column 100 of the third core 10c is integrally formed without a gap. The two adjacent side walls 108a and 108b of the first core 10a and the second core 10b are opposite to each other at the inner column 100.

[0083] After the thermally conductive filler 14 is filled into the housing 16, at least a portion of the non-joining area 104a is not covered by the thermally conductive filler 14. Fig.11 As shown, the lower portion of the non-bonding area 104a between the two adjacent side walls 108a, 108b and the two bonding areas 106 are covered by the thermally conductive filler 14, and the upper portion of the non-bonding area 104a is not covered by the thermally conductive filler 14. In addition, the non-bonding area 104b above the inner column 100 of the third core body 10c is also covered by the thermally conductive filler 14. As a result, the inner column 100 having the upper portion of the non-bonding area 104a can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding an increase in the loss of the magnetic core 10. For example, when the magnetic element 1" is an inductor or transformer with a power of 3.7KW, the maximum thermal stress can be reduced from 48Mpa to 16Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 150°C to 120°C.

[0084] See also Fig.12 , Fig.12 FIG. 4 is a cross-sectional view of a magnetic element 1 ″′ according to another embodiment of the present invention.

[0085] The main difference between the magnetic element 1'' and the magnetic element 1 mentioned above is that the thermal conductive filler 14 covers at least one non-bonding area 104, wherein at least one non-bonding area 104 is located at at least two outer columns 102, and at least one bonding area 106 is located at the inner column 100. Fig.12 As shown. In the present embodiment, the first core 10a and the second core 10b are two of an E-type magnetic core, a PQ-type magnetic core, a T-type magnetic core, a UU-type magnetic core, a U-type magnetic core, a UI-type magnetic core, an EI-type magnetic core, an I-type magnetic core or an F-type magnetic core, so that two non-joining areas 104 are located at two outer columns 102, and a joining area 106 is located at the inner column 100. In other words, the two outer columns 102 of the magnetic core 10 are not joined, and the inner column 100 of the magnetic core 10 is joined. After the thermal conductive filler 14 is filled in the shell 16, the thermal conductive filler 14 covers a part of the magnetic core 10, the two non-joining areas 104 located at the two outer columns 102, and the joining area 106 located at the inner column 100. As a result, the two outer columns 102 with the non-joining areas 104 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10. For example, when the magnetic component 1'' is an inductor or transformer with a power of 6.6KW, the maximum thermal stress can be reduced from 68Mpa to 32.4Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 154°C to 115.2°C.

[0086] See also Fig.13 , Fig.13 FIG. 4 is a cross-sectional view of a magnetic element 1 ″″ according to another embodiment of the present invention.

[0087] The main difference between the magnetic element 1"" and the above-mentioned magnetic element 1 is that, in addition to the magnetic core 10, at least one coil 12 and the thermal conductive filler 14, the magnetic element 1"" also includes a bracket 20', such as Fig.13 As shown. The magnetic core 10 includes an inner column 100, at least two outer columns 102 and a plurality of non-bonding areas 104. The plurality of non-bonding areas 104 are located at the inner column 100 and the at least two outer columns 102. The bracket 20' is sleeved on the inner column 100. An upper surface 208 of the bracket 20' can be bonded to an inner plate surface 110 of the magnetic core 10 by colloid. At least one coil 12 is disposed on the bracket 20'. After the thermal conductive filler 14 is filled in the shell 16, the thermal conductive filler 14 covers a portion of the magnetic core 10 and does not cover the plurality of non-bonding areas 104. As a result, the inner column 100 and the at least two outer columns 102 having the plurality of non-bonding areas 104 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding an increase in the loss of the magnetic core 10. In another embodiment, a lower surface 210 of the bracket 20 ′ may be further bonded to another inner plate surface 112 of the magnetic core 10 by adhesive, wherein the two inner plate surfaces 110 , 112 are opposite to each other.

[0088] See also Fig.14 , Fig.14 FIG. 4 is a three-dimensional diagram of a magnetic element 3 according to another embodiment of the present invention.

[0089] like Fig.14 As shown, the magnetic core 30 of the magnetic element 3 has a plate portion 300 and a V-shaped groove 302, wherein the V-shaped groove 302 is formed on one side of the plate portion 300. In this embodiment, the side of the plate portion 300 having the V-shaped groove 302 is a continuous side without a discontinuous geometric structure to avoid stress concentration. In this embodiment, the position of the junction between the two sides of the V-shaped groove 302 corresponds to the inner column of the magnetic core 30.

[0090] See also Fig.15 , Fig.15 FIG. 4 is a three-dimensional diagram of a magnetic element 3 according to another embodiment of the present invention.

[0091] like Fig.15 As shown, the radian R of the tip of the V-shaped groove 302 may be greater than 5 to prevent the V-shaped groove 302 from being too sharp and affecting the strength of the plate portion 300. For example, if the radian R is 0.8, the maximum thermal stress of the corresponding V-shaped groove 302 may be 85.6 MPa; if the radian R is 5, the maximum thermal stress of the corresponding V-shaped groove 302 may be 64.3 MPa. The magnetic core 30 having the V-shaped groove 302 and the radian R is not limited in application and may also be applied in other embodiments.

[0092] In summary, in one embodiment, at least one non-joining area may be located at the inner column or at least two outer columns, and at least a portion of at least one non-joining area may not be covered by the thermal conductive filler. Thus, the inner column or at least two outer columns with the non-joining area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding the increase in the loss of the magnetic core. In addition, in another embodiment, at least one non-joining area may be located at at least two outer columns, and the thermal conductive filler may cover at least one non-joining area or / and the joining area located at the inner column. Similarly, at least two outer columns with the non-joining area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding the increase in the loss of the magnetic core. It should be noted that the temperature difference described in the present invention refers to the temperature difference between two different positions of the magnetic core at the same time. In another embodiment, the coil and the partition can be stacked on each other and directly sleeved on the inner column of the magnetic core, so that the coil does not need to be wound around the bracket, and the insulation and heat dissipation effect between the primary side coil and the secondary side coil and between the coil and the magnetic core can be improved. Thus, the magnetic element will not be limited by the size and space of the bracket, and the partition can be in close contact with the coil, or the lead cover structure can be extended between the two coils to fix and minimize the distance and gap between the partition and the coil, so as to miniaturize the size of the magnetic element.

[0093] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A magnetic element, comprising: A magnetic core comprising an inner column and at least two outer columns; at least one partition; and At least two coils, the at least two coils and the at least one partition are stacked on each other and directly sleeved on the inner column; in, Each coil is wound by conducting wires staggeredly wrapped with at least three layers of insulating tapes.

2. The magnetic element as described in claim 1, wherein the insulating tape is stacked from the first layer to at least the second and third layers in a staggered manner, and the staggered overlap ratio W2 / W1 is greater than 67%, W1 is the width of the insulating tape, and W2 is the overlap width.

3. The magnetic element as claimed in claim 1, further comprising a thermally conductive filler covering a portion of the magnetic core and filling a gap between the opposite overlapping surfaces of the at least two coils. 4 . The magnetic element as claimed in claim 3 , wherein the thermally conductive filler is filled into the opposite surfaces between the inner column and the at least two coils. 5 . The magnetic element as claimed in claim 3 , wherein the thermally conductive filler covers the outward surfaces of the at least two coils and the at least one partition. 6 . The magnetic element as claimed in claim 1 , wherein the winding structure of each coil is formed by extending the wire from the outer sides of the upper and lower layers.

7. The magnetic element as described in claim 1 further includes a lead cover, which is directly sleeved on the inner column and stacked above the at least one partition and the at least two coils, and the at least one partition also includes a wire groove corresponding to a wire groove of the lead cover, and the end wire of the coil is led out of the magnetic core through the wire groove of the lead cover and the wire groove of the partition. 8 . The magnetic element as claimed in claim 7 , wherein the structure of the lead cover extends between the at least two coils to fix and minimize the distance between the at least one partition and the at least two coils.

9. The magnetic element as claimed in claim 1, wherein the material of the at least one partition has magnetic conductivity and electrical insulation properties.

10. The magnetic element as claimed in claim 1, wherein the magnetic element does not have a bracket covering the inner column. 11 . The magnetic element as claimed in claim 1 , wherein the magnetic core has a plate portion and a V-shaped groove, and the V-shaped groove is formed on a side of the plate portion. 12 . The magnetic element as claimed in claim 11 , wherein a position of a joint between two side edges of the V-shaped groove corresponds to the inner column. 13 . The magnetic element as claimed in claim 11 , wherein the curvature of the tip of the V-shaped groove is greater than 5°. 14 . The magnetic element as claimed in claim 1 , further comprising a heat sink disposed on the magnetic core, wherein the heat sink contacts a top surface and a side surface of the magnetic core. 15 . The magnetic element as claimed in claim 14 , wherein the heat sink is L-shaped, and a length of a portion of the heat sink contacting the side surface of the magnetic core is smaller than a height of the magnetic core. 16 . The magnetic element as claimed in claim 14 , wherein the heat sink is attached to the magnetic core by a colloid with a Shore D or Shore A hardness less than 80. 17 . The magnetic element as claimed in claim 1 , wherein the at least two coils include a primary coil and a secondary coil, and the at least one partition includes an annular structure disposed between the primary coil and the secondary coil.

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