Coil assembly

Abstract

To provide a coil assembly which suppresses current deviation between plane coils.SOLUTION: Coil assemblies 100, 101 and 102 include a plurality of coil layers S1, S2, S11, S12, S21 and S22 which are laminated in a lamination direction and each have a plurality of plane coils 1 to 8, 1 to 10, and 1 to 12 that are wound in a plane direction crossing the lamination direction and are connected in parallel with each other. The plurality of coil layers constitute a plurality of coil parts a to d and a to e which are constituted of at least one plane coil and are connected in parallel with each other, at least a part of the plurality of coil layers includes first pitch wire pairs having pitches between the adjacent wires as first pitches, and second pitch wire pairs having second pitches between the adjacent wires larger than the first pitches, and the first pitch wire pairs are positioned in the width direction outer side of the coil widths of the coil layers rather than the second pitch wire pairs.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a coil assembly.

Background Art

[0002] Conventionally, a coil assembly including a plurality of coil layers having planar coils has been used. When such a coil assembly is used together with a magnetic body such as a magnetic sheet, the self-inductance of the planar coils differs due to the difference in the distance from the magnetic body. As a result, in a configuration in which a plurality of coil portions each constituted by one or a plurality of planar coils connected in series are connected in parallel, a difference in impedance may occur in each coil portion. When such a difference in impedance occurs, current concentration occurs in some of the coil portions, resulting in a problem that the loss increases. Therefore, a technique has been proposed in which, in a coil layer having a larger distance from the magnetic body, the line length of the planar coil is made longer to suppress the difference in impedance between the coil portions (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the coil assembly as described above, the mutual inductance between the coil portions affects the impedance of each coil portion. However, in the above-described technique of adjusting the line length of the planar coil according to the distance from the magnetic body, no consideration is given to the mutual inductance between the coil portions, and there is still a possibility that the difference in impedance between the coil portions described above may occur.

[0005] Such problems can occur not only in configurations using a magnetic body together with a coil assembly, but also in configurations not using a magnetic body. For example, they can occur even in a coil assembly having a configuration in which planar coils included in different coil layers are connected in series to form one coil portion, and a plurality of such coil portions are connected in parallel. From this, a technique capable of further suppressing current bias between coil portions is desired.

Means for Solving the Problems

[0006] The present disclosure can be realized in the following forms.

[0007] According to one aspect of the present disclosure, a coil assembly (100, 101, 102) is provided. The coil assembly includes a plurality of coil layers (S1, S2, S11, S12, S21, S22) laminated in a stacking direction, and each of the plurality of coil layers has a plurality of planar coils (1 to 8, 1 to 10, 1 to 12) wound in a planar direction intersecting the stacking direction and connected in parallel with each other. The plurality of coil layers are a plurality of coil portions (a to d, a to e) each constituted by at least one of the planar coils, and constitute a plurality of coil portions connected in parallel with each other. At least some of the plurality of coil layers include a first pitch wire set in which the pitch between adjacent strands is a first pitch, and a second pitch wire set in which the pitch between adjacent strands is a second pitch larger than the first pitch. The first pitch wire set is located outside the width direction of the coil width of the coil layer, more than the second pitch wire set.

[0008] According to the coil assembly of this form, at least a part of a plurality of coil layers includes a first pitch strand group in which the pitch between adjacent strands is a first pitch, and a second pitch strand group in which the pitch between adjacent strands is a second pitch greater than the first pitch. The first pitch strand group is located outside in the width direction than the second pitch strand group. For this reason, the mutual inductance between the coil portions located inside in the width direction can be reduced compared to the mutual inductance between the coil portions located outside in the width direction, suppressing the occurrence of a difference in impedance between the coil portion located inside in the width direction and the coil portion located outside in the width direction, and suppressing the current bias between the coil portions.

Brief Description of Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0010] A. First Embodiment: A1. Overall Configuration: As shown in FIG. 1, the coil assembly 100 of the present embodiment includes a first coil layer S1 and a second coil layer S2. The coil assembly 100 forms a coil (inductor) as a whole. In the present embodiment, the coil assembly 100 is used in the non-contact power supply system 500 shown in FIG. 2. The detailed configuration of the coil assembly 100 will be described later. The non-contact power supply system 500 is a system for supplying power from the power supply device 300 to the load device 300A electrically connected to the power receiving device 200A by transmitting the power supplied from the power supply device 300 non-contact from the power transmitting device 200 to the power receiving device 200A.

[0011] As shown in FIG. 2, the non-contact power supply system 500 includes a resonance circuit 150 including the coil assembly 100, a power transmitting device 200 including the resonance circuit 150, a power transmission output circuit 210, a power receiving side coil assembly 100A, a resonance circuit 150A including the power receiving side coil assembly 100A, a power receiving device 200A including the resonance circuit 150A, and a rectification circuit 210A.

[0012] The resonance circuit 150 has a configuration in which an inductor composed of the coil assembly 100 and a capacitor (not shown) are connected in series. The power transmitting device 200 includes the resonance circuit 150 and performs non-contact power supply to the power receiving device 200A using the power supplied from the power transmission output circuit 210.

[0013] The power transmission output circuit 210 includes an inverter circuit and a filter circuit (not shown), converts the DC power supplied from the power supply device 300 into AC power at a predetermined operating frequency, and also removes the noise components of the AC power and supplies it to the power transmission device 200.

[0014] The coil assembly 100 includes a magnetic body 110 and a shield member 112. The magnetic body 110 is a thin plate-shaped member made of a magnetic material, and in this embodiment, it is formed of ferrite. As shown in FIG. 2, the magnetic body 110 and the shield member 112 are arranged and used on the side opposite to the side facing the power receiving side coil assembly 100A as viewed from the coil assembly 100. The magnetic body 110 makes the magnetic flux generated in the coil assembly 100 more efficiently directed toward the power receiving side coil assembly 100A, and increases the magnetic flux penetrating the power receiving side coil assembly 100A.

[0015] The shield member 112 is a plate-shaped member made of aluminum or an aluminum alloy. The shield member 112 has a function of shielding the magnetic flux generated in the coil assembly 100 so as not to escape to the outside. In addition, the shield member 112 dissipates the heat generated in the coil assembly 100. Note that the shield member 112 may be constituted by copper or other metal plates instead of aluminum or an aluminum alloy. Other detailed configurations of the coil assembly 100 will be described later. Note that the coil assembly 100 may not include the magnetic body 110 and the shield member 112.

[0016] The power receiving side coil assembly 100A is an inductor that constitutes a part of the resonance circuit 150A included in the power receiving device 200A. The configuration of the power receiving side coil assembly 100A is the same as the configuration of the coil assembly 100, which will be described in detail later. Similar to the coil assembly 100, the power receiving side coil assembly 100A includes a power receiving side magnetic body 110A and a shield member 112A. The power receiving side magnetic body 110A has the same configuration as the magnetic body 110 described above. Also, the shield member 112A has the same configuration as the shield member 112 described above.

[0017] The power receiving device 200A includes a resonance circuit 150A in which an inductor composed of a power receiving side coil assembly 100A and a capacitor (not shown) are connected in series. While power is being supplied to the power transmission device 200, in the power transmission device 200, the resonance circuit 150 is in a resonance state at a predetermined operating frequency and a magnetic flux is generated. Such a magnetic flux penetrates the power receiving side coil assembly 100A of the power receiving device 200A, and an induced electromotive force is generated in the power receiving device 200A by such a magnetic flux, and power transmission and reception are performed. The rectifier circuit 210A includes a bridge circuit (not shown) and a smoothing capacitor, and converts the AC power output from the power receiving device 200A into DC power and supplies it to the load device 300A.

[0018] The non-contact power supply system 500 having the above configuration may be used, for example, by arranging the power transmission output circuit 210 and the power transmission device 200 underground or on the ground surface, mounting the power receiving device 200A, the rectifier circuit 210A, and the load device 300A on a moving body such as an electric vehicle, and supplying power to the traveling moving body. In such a configuration, the load device 300A corresponds to a battery mounted on the moving body, a motor, or the like.

[0019] A2. Detailed configuration of the coil assembly 100: In the coil assembly 100, the two coil layers S1 and S2 shown in FIG. 1 are laminated along the Z axis. Specifically, they are laminated in the +Z direction in the order of the first coil layer S1 and the second coil layer S2. That is, the Z direction corresponds to the "lamination direction" in the present disclosure. In FIG. 1, the X axis, Y axis, and Z axis that are orthogonal to each other are shown, and such XYZ axes correspond to the XYZ axes in other drawings. Also, the direction from the power transmission device 200 shown in FIG. 2 toward the power receiving device 200A corresponds to the +Z direction. In FIG. 1, the magnetic body 110 and the shield member 112 are omitted.

[0020] Each coil layer S1, S2 includes a plurality of planar coils formed by a wire wound in the X-Y plane. In the present embodiment, the wire is made of a copper foil. Also, the number of planar coils included in each coil layer S1, S2 is "4", that is, an even number. Each coil layer S1, S2 has a configuration in which an insulator such as prepreg is sandwiched between the coil patterns of the planar coils made of copper foil. Note that the planar coil located on the outermost (surface side) of the coil assembly 100 in the Z direction may be covered with, for example, a solder resist.

[0021] The first coil layer S1 includes a first planar coil 1, a second planar coil 2, a third planar coil 3, and a fourth planar coil 4. The second coil layer S2 includes a fifth planar coil 5, a sixth planar coil 6, a seventh planar coil 7, and an eighth planar coil 8. The number of turns of each of the planar coils 1 to 8 is "1". Note that the number of turns of each of the planar coils 1 to 8 is not limited to 1 and may be any number.

[0022] Four through-hole vias v1, v2, v3, v4 penetrating each of the coil layers S1, S2 are formed in the coil assembly 100. One end of each of the fourth planar coil 4 and the fifth planar coil 5 is connected to the through-hole via v1. One end of each of the third planar coil 3 and the sixth planar coil 6 is connected to the through-hole via v2. One end of each of the second planar coil 2 and the seventh planar coil 7 is connected to the through-hole via v3. One end of each of the first planar coil 1 and the eighth planar coil 8 is connected to the through-hole via v4.

[0023] The first coil layer S1 includes a connection terminal portion t1 at its central part. The second coil layer S2 includes a connection terminal portion t2 at its central part. The other ends of the first planar coil 1, the second planar coil 2, the third planar coil 3, and the fourth planar coil 4 are connected to the connection terminal portion t1. The other ends of the fifth planar coil 5, the sixth planar coil 6, the seventh planar coil 7, and the eighth planar coil 8 are connected to the connection terminal portion t2. The connection terminal portion t1 and the connection terminal portion t2 are exposed on the -Z-direction end face and the +Z-direction end face of the coil assembly 100, and are connected to the power transmission device 200 via a capacitor (not shown).

[0024] As shown in FIG. 3, the first planar coil 1 and the eighth planar coil 8 are connected in series to form a coil portion a. Similarly, the second planar coil 2 and the seventh planar coil 7 are connected in series to form a coil portion b, the third planar coil 3 and the sixth planar coil 6 are connected in series to form a coil portion c, and the fourth planar coil 4 and the fifth planar coil 5 are connected in series to form a coil portion d. These four coil portions a to d are connected in parallel to each other. Hereinafter, the current flowing through the coil portion a is referred to as current Ia. Similarly, the current flowing through the coil portion b is referred to as Ib, the current flowing through the coil portion c is referred to as Ic, and the current flowing through the coil portion d is referred to as Id. In this way, by connecting the four coil portions a to d in parallel, each wire element can be made thinner, the generation of eddy currents can be suppressed, and the power transmission efficiency can be improved. Note that in FIG. 3, the magnetic body 110 and the shield member 112 are omitted.

[0025] In FIG. 4, a cross-section taken along line IV-IV in FIG. 1 is shown. As shown in FIG. 4, among adjacent strands in the direction along the X-Y plane (hereinafter referred to as the "plane direction") in the first coil layer S1, a strand pair consisting of two strands located outside the width direction of the coil width of the first coil layer S1, namely, the strand of the first planar coil 1 and the strand of the second planar coil 2, and the strand pair consisting of the strand of the third planar coil 3 and the strand of the fourth planar coil 4 are all arranged such that the pitch between the strands is the first pitch p1. That is, the strand pair consisting of the strand of the first planar coil 1 and the strand of the second planar coil 2, and the strand pair consisting of the strand of the third planar coil 3 and the strand of the fourth planar coil 4 each correspond to the "first pitch strand pair" in the present disclosure. Note that the "pitch between strands" means the planar direction distance between the center in the width direction of each strand and the center in the width direction of an adjacent other strand. Also, the "coil width" means the width of the entire strand group constituting one turn, more specifically, the distance between the inner end of the strand located most inward in the plane direction and the outer end of the strand located most outward in the plane among the strand group constituting one turn. Further, the "outer side in the width direction" means a region where the distance from the central position of the coil width is farther in the strand group constituting one turn. In this embodiment, it means a region where the distance from the central position Ct1 is farther.

[0026] Among the adjacent strands in the plane direction in the first coil layer S1, the pair of two strands located inside the width direction of the coil width of the first coil layer S1, in this embodiment, the pair of two strands closest to the central position Ct1 which is the central position of the coil width. The strand pairs of the strands of the second planar coil 2 and the strands of the third planar coil 3 are arranged such that the pitch between the strands is the second pitch p2. That is, the strand pair of the strands of the second planar coil 2 and the strands of the third planar coil 3 corresponds to the "second pitch strand pair" in the present disclosure. "Inside the width direction" means a region where the distance from the central position of the coil width is closer in the strand group constituting one turn. In this embodiment, it means a region where the distance from the central position Ct1 is closer. As described above, in this embodiment, the first pitch strand pair is located outside the width direction of the coil width of the first coil layer S1 compared to the second pitch strand pair. The effects achieved by the first pitch strand pair and the second pitch strand pair having such a positional relationship will be described later.

[0027] The strand group constituting the second coil layer S2 also has the same positional relationship as the first coil layer S1. That is, among the adjacent strands in the plane direction in the second coil layer S2, the strand pair of the strands of the fifth planar coil 5 and the strands of the sixth planar coil 6, which are a pair of two strands located outside the width direction of the coil width of the second coil layer S2, and the strand pair of the strands of the seventh planar coil 7 and the strands of the eighth planar coil 8 are both arranged such that the pitch between the strands is the first pitch p1 and correspond to the first pitch strand pair. On the other hand, the strands of the sixth planar coil 6 and the strands of the seventh planar coil 7, which are a pair of two strands located inside the width direction of the coil width of the second coil layer S2, are arranged such that the pitch between the strands is the second pitch p2 and correspond to the second pitch strand pair. Note that in each of the coil layers S1 and the second coil layer S2, the central position Ct1 of the coil width coincides with each other.

[0028] The second pitch p2 is larger than the first pitch p1. Also, the distance between the strands constituting the second pitch strand set is larger than the distance between the strands constituting the first pitch strand set. The "distance between the strands" means the width of the space formed between two adjacent strand sets. The reason for such a configuration will be described with reference to FIGS. 3 and 5.

[0029] The equivalent circuit shown in FIG. 3 is represented by Expressions 1-a, 1-b, 1-c, and 1-d shown in the uppermost row of FIG. 5. In each of Expressions 1-a to 1-d, V is the voltage between the terminals of coil parts a to d, Ra to Rd are the resistances of each of coil parts a to d, La to Ld are the self-inductances of each of coil parts a to d, Mxy (x = a to d, y = a to d) is the mutual inductance between coil part x and coil part y, and ω is the angular frequency. Note that Ia to Id are the currents flowing through each of coil parts a to d as described above.

[0030] In the four coil parts a to d connected in parallel to each other, in a state where there is no current bias, Ia = Ib = Ic = Id. Therefore, Expressions 1-a to 1-d can be transformed into the second-stage Expressions 2-a to 2-d. Here, if the "sum of the self-inductance and the mutual inductance" in Expressions 2-a to 2-d is replaced with Sa, Sb, Sc, and Sd (hereinafter referred to as "inductance parameters") as in the third-stage Expressions 3-a to 3-d, the fourth-stage Expressions 4-a to 4-d are obtained. In the four coil parts a to d, in an ideal state where there is no current bias, the left sides of Expressions 4-a to 4-d are all equal to "V / Ia". Thus, in order to make the state without current bias, Ra = Rb = Rc = Rd should hold for the resistances, and Sa = Sb = Sc = Sd should hold for the inductance parameters.

[0031] Regarding the resistances Ra to Rd in the present embodiment, the same thickness of wire is used for each coil part a to d, and the wire lengths of each coil part a to d are made equal to each other. Specifically, as shown in FIG. 1, the coil part a is configured by serially connecting a first planar coil 1 wound radially outward in the first coil layer S1 and an eighth planar coil 8 wound radially inward in the second coil layer S2. On the other hand, the coil part d is configured by serially connecting a fourth planar coil 4 wound radially inward in the first coil layer S1 and a fifth planar coil 5 wound radially outward in the second coil layer S2. By configuring the coil part a and the coil part d in this way, the wire lengths of the wires are made equal between the coil part a and the coil part d.

[0032] Similarly, the coil part b is configured by serially connecting a second planar coil 2 wound radially outward in the first coil layer S1 and a seventh planar coil 7 wound radially inward in the second coil layer S2. On the other hand, the coil part c is configured by serially connecting a third planar coil 3 wound radially inward in the first coil layer S1 and a sixth planar coil 6 wound radially outward in the second coil layer S2. By configuring the coil part b and the coil part c in this way, the wire lengths of the wires are made equal between the coil part b and the coil part c. Note that the wire lengths of the wires of the coil part a and the coil part d and the wire lengths of the wires of the coil part b and the coil part c are configured to be equal to each other.

[0033] Among the inductance parameters Sa to Sd, the self-inductances La to Ld are made uniform with each other in the present embodiment by using wire elements of the same thickness and winding the wire elements with the same number of turns in each of the coil portions a to d. However, the mutual inductance between two coil portions with closer distances to each other is larger than the mutual inductance between two coil portions with farther distances to each other. More specifically, the distance between the coil portion b and the coil portion c is smaller than the distance between the coil portion a and the coil portion d. That is, the mutual inductance Mbc between the coil portion b and the coil portion c is larger than the mutual inductance Mad between the coil portion a and the coil portion d. Therefore, the inductance parameters Sb and Sc including the larger mutual inductance Mbc in the formula are larger than the inductance parameters Sa and Sd including the smaller mutual inductance Mad in the formula. Thus, differences can occur in the inductance parameters Sa to Sd.

[0034] Therefore, in the present embodiment, due to the above-described difference in pitch, differences are caused in the mutual inductance Mxy (x = a to d, y = a to d), and by such differences, the differences in the above-described inductance parameters Sa to Sd are suppressed. Specifically, in the first coil layer S1, the second pitch p2 between the wire element of the second planar coil 2 and the wire element of the third planar coil 3 is made larger than the first pitch p1 between the wire element of the first planar coil 1 and the wire element of the second planar coil 2 and between the wire element of the third planar coil 3 and the wire element of the fourth planar coil 4, thereby reducing the mutual inductance Mbc and suppressing the differences in the inductance parameters Sa to Sd. Thereby, the occurrence of differences in impedance in each of the coil portions a to d is suppressed, and the loss caused by current concentration in a specific coil portion can be suppressed.

[0035] Also, similarly in the second coil layer S2, by making the second pitch p2 between the wire elements of the sixth planar coil 6 and the wire elements of the seventh planar coil 7 larger than the first pitch p1 between the wire elements of the fifth planar coil 5 and the wire elements of the sixth planar coil 6 and between the wire elements of the seventh planar coil 7 and the wire elements of the eighth planar coil 8, the mutual inductance Mbc is reduced and the differences in the inductance parameters Sa to Sd are suppressed. Thereby, even in the second coil layer S2, the occurrence of differences in impedance in each of the coil portions a to d is suppressed, and the loss caused by current concentration in a specific coil portion can be suppressed.

[0036] In the coil assembly 100 of the present embodiment, by adjusting the first pitch p1 and the second pitch p2, the inductance parameters Sa to Sd, that is, the sum of the self - inductance and the mutual inductance, are configured to be equal to each other. Note that "the sum of the self - inductance and the mutual inductance being equal to each other" has a broad meaning that includes not only the case where the sums are exactly equal, but also the case of the relationship between the sum of the self - inductance and the mutual inductance that can reduce the differences in the inductance parameters between the coil portions a to d compared to the configuration where the first pitch p1 and the second pitch p2 are equal to each other.

[0037] A3. Example: The coil assembly 100 of the first embodiment shown in FIG. 4 was numerically analyzed as Example 1, and the coil assembly 900 of Comparative Example 1 shown in FIG. 6 was also numerically analyzed. Then, as shown in FIG. 7, for these coil assemblies 100 and 900, the mutual inductance Mbc, the inductance parameters Sa to Sd, etc. were numerically analyzed to confirm the effects.

[0038] In Example 1 shown in FIG. 4, the distance from the central axis (the axis extending parallel to the Z-axis from the central position when viewed in the Z direction) Cu1 of each coil layer S1, S2 to the central position Ct1 was set to 20 mm (millimeters). Also, the thickness of the wire strand was set to 300 μm (micrometers), and the width of the wire strand was set to 300 μm. Further, the coil width was set to 6 mm. Also, as shown in FIG. 7, the first pitch p1 was set to 0.9 mm, and the second pitch p2 was set to 4.5 mm.

[0039] The thickness of the magnetic body 110 and the thickness of the shield member 112 were each set to 1 mm. Also, the magnetic body 110 was made of ferrite. Further, the planar shapes of the planar coils constituting each coil layer S1, S2, the magnetic body 110, and the shield member 112 were each circular. The radius of the magnetic body 110 and the radius of the shield member 112 were each set to 30 mm. A current of 1 A was passed through the coil assembly 100 having the above configuration at a frequency of 85 kHz.

[0040] On the other hand, in the coil assembly 900 of Comparative Example 1, unlike the coil assembly 100 of Example 1, the sizes of both the first pitch p1 and the second pitch p2 are 1.9 mm, and the other configurations are the same.

[0041] As shown in FIG. 7, by making the size of the second pitch p2 larger than the first pitch p1, the mutual inductance Mbc becomes smaller. For this reason, the inductance parameters Sb and Sc can be made smaller, and the difference between the inductance parameters Sa to Sd can be suppressed. As a result, the difference between the currents Ia to Id becomes smaller, and in Example 1, the AC resistance R of the coil assembly 100 was suppressed to be lower than that of Comparative Example 1.

[0042] According to the coil assembly 100 of the first embodiment described above, it includes a first pitch strand group in which the pitch between adjacent strands is the first pitch p1, and a second pitch strand group in which the pitch between adjacent strands is the second pitch p2 greater than the first pitch p1. The first pitch strand group is located on the outer side in the width direction than the second pitch strand group. Therefore, the mutual inductance between the coil portions located on the inner side in the width direction can be reduced compared to the mutual inductance between the coil portions located on the outer side in the width direction, suppressing the occurrence of impedance differences between the coil portion located on the inner side in the width direction and the coil portion located on the outer side in the width direction, and suppressing the current bias between the coil portions.

[0043] Also, in each of the coil portions a to d, since the planar coil wound on the inner side in the radial direction and the planar coil wound on the outer side in the radial direction are connected in series, the difference in the wire length of the strands between the coil portions is suppressed, and the occurrence of differences in impedance between the coil portions can be suppressed.

[0044] Also, the number of planar coils constituting each of the coil layers S1 and S2 is "4", that is, an even number, and the second pitch strand group is composed of a strand group of the two strands and the three strands that are the two strands closest to the central position of the coil width. Therefore, in a coil assembly having a coil layer composed of an even number of planar coils, the current bias between the coil portions can be suppressed.

[0045] Also, between the coil portions a to d, since the sum of the self-inductance and the mutual inductance is equal to each other, the occurrence of differences in impedance between the coil portions a to d can be suppressed.

[0046] B. Second Embodiment: The coil assembly 101 of the second embodiment shown in FIG. 8 is different from the coil assembly 100 of the first embodiment in that the number of planar coils constituting each coil layer is "5", that is, an odd number, and other configurations are the same. The same reference numerals are given to the same configurations as those in the coil assembly 100 in the coil assembly 101, and the detailed description thereof is omitted.

[0047] B1. Detailed Configuration of Coil Assembly 101: FIG. 8 shows a cross-section of the coil assembly 101 at a position similar to the IV-IV cross-section in FIG. 1. As shown in FIG. 8, the coil assembly 101 includes a first coil layer S11 and a second coil layer S12 laminated on each other. The first coil layer S11 includes a first planar coil 1, a second planar coil 2, a third planar coil 3, a fourth planar coil 4, and a fifth planar coil 5. The second coil layer S12 includes a sixth planar coil 6, a seventh planar coil 7, an eighth planar coil 8, a ninth planar coil 9, and a tenth planar coil 10. The number of turns of each of the planar coils 1 to 10 is "1". Note that the number of turns of each of the planar coils 1 to 10 is not limited to 1 and may be any number.

[0048] In each of the coil layers S11 and S12, the central position Ct2 of the coil width coincides with each other. In the present embodiment, the third planar coil 3 of the first coil layer S11 and the eighth planar coil 8 of the second coil layer S12 are both located at the central position Ct2.

[0049] As shown in FIG. 9, in the present embodiment, the first planar coil 1 and the tenth planar coil 10 are connected in series to form a coil portion a. Similarly, the second planar coil 2 and the ninth planar coil 9 are connected in series to form a coil portion b, the third planar coil 3 and the eighth planar coil 8 are connected in series to form a coil portion c, the fourth planar coil 4 and the seventh planar coil 7 are connected in series to form a coil portion d, and the fifth planar coil 5 and the sixth planar coil 6 are connected in series to form a coil portion e. These five coil portions a to e of the planar coil 5 are connected in parallel to each other. Hereinafter, the current flowing through the coil portion a is referred to as current Ia, the current flowing through the coil portion b is referred to as current Ib, the current flowing through the coil portion c is referred to as current Ic, the current flowing through the coil portion d is referred to as current Id, and the current flowing through the coil portion e is referred to as current Ie, respectively.

[0050] In the present embodiment, in the first coil layer S11, a wire set of the wires of the first planar coil 1 and the second planar coil 2, which are two wire sets located on the outer side in the width direction of the coil width of the first coil layer S11, and a wire set of the wires of the fourth planar coil 4 and the fifth planar coil 5 are each arranged such that the pitch between the respective wires is the first pitch p1, corresponding to the first pitch wire set. Similarly, in the second coil layer S12, a wire set of the wires of the sixth planar coil 6 and the seventh planar coil 7, which are two wire sets located on the outer side in the width direction of the second coil layer S12, and a wire set of the wires of the ninth planar coil 9 and the tenth planar coil 10 are each arranged such that the pitch between the respective wires is the first pitch p1, corresponding to the first pitch wire set.

[0051] On the other hand, in the first coil layer S11, a wire set of the wires of the second planar coil 2 and the third planar coil 3, which are two wire sets located on the inner side in the width direction of the first coil layer S11, and a wire set of the wires of the third planar coil 3 and the fourth planar coil 4 are each arranged such that the pitch between the respective wires is the second pitch p2, corresponding to the second pitch wire set. Similarly, in the second coil layer S12, a wire set of the wires of the seventh planar coil 7 and the eighth planar coil 8, which are two wire sets located on the inner side in the width direction of the second coil layer S12, and a wire set of the wires of the eighth planar coil 8 and the ninth planar coil 9 are each arranged such that the pitch between the respective wires is the second pitch p2, corresponding to the second pitch wire set.

[0052] B2. Example: The coil assembly 101 of the second embodiment shown in FIG. 8 was numerically analyzed as Example 2, and the coil assembly 901 of Comparative Example 2 shown in FIG. 10 was also numerically analyzed. Then, as shown in FIG. 11, mutual inductances Mbc, Mcd, Mbd, inductance parameters Sa to Se, etc. of these coil assemblies 101 and 901 were numerically analyzed to confirm their effects.

[0053] As shown in Fig. 11, in the second embodiment, the first pitch p1 was 0.6 mm and the second pitch p2 was 2.25 mm. On the other hand, in the comparative example 2, the sizes of both the first pitch p1 and the second pitch p2 were 1.425 mm. Other configurations are the same as those in which numerical analysis was performed in the first embodiment.

[0054] As shown in Fig. 11, by making the size of the second pitch p2 larger than the first pitch p1, the mutual inductances Mbc, Mcd, and Mbd become smaller. For this reason, the inductance parameters Sb, Sc, and Sd can be made smaller, and the differences in the inductance parameters Sa to Se can be suppressed. As a result, the differences in the currents Ia to Ie become smaller, and in the second embodiment, the AC resistance R of the coil assembly 101 is suppressed to be lower than that in the comparative example 2.

[0055] In the coil assembly 101 of the second embodiment described above, the number of planar coils constituting each of the coil layers S11 and S1 (should it be S12?) is "5", that is, an odd number. Also in the coil assembly 101 having a coil layer constituted by such an odd number of planar coils, similar to the first embodiment, the current bias between the coil portions can be suppressed.

[0056] C. Third Embodiment: The coil assembly 102 of the third embodiment shown in Figs. 12 and 13 is different from the 100 of the first embodiment in that it includes a housing 120, and the other configurations are the same. The same reference numerals are given to the same configurations as those in the coil assembly 100 in the coil assembly 102, and the detailed description thereof is omitted.

[0057] It should be noted that there seems to be a small error in the original text where it says "each of the coil layers S11, S12" and then later refers to "S1" in the odd number description. This has been left as is in the translation for accuracy. Also, for the tags - , they are left unchanged as per the requirements.As shown in FIG. 12, the coil assembly 102 includes a first coil layer S21 and a second coil layer S22 laminated on each other. The first coil layer S21 includes a first planar coil 1, a second planar coil 2, a third planar coil 3, a fourth planar coil 4, a fifth planar coil 5, and a sixth planar coil 6. The second coil layer S12 includes a seventh planar coil 7, an eighth planar coil 8, a ninth planar coil 9, a tenth planar coil 10, an eleventh planar coil 11, and a twelfth planar coil 12. The number of turns of each of the planar coils 1 to 12 is "1.5". Note that the number of turns of each of the planar coils 1 to 12 is not limited to 1.5 and may be any number.

[0058] The coil assembly 102 includes, at its central portion, four through-hole vias v21, v22, v23, v24, v25, v26 that penetrate each coil layer S21, S22. One end of each of the sixth planar coil 6 and the seventh planar coil 7 is connected to the through-hole via v21. One end of each of the fifth planar coil 5 and the eighth planar coil 8 is connected to the through-hole via v22. One end of each of the fourth planar coil 4 and the ninth planar coil 9 is connected to the through-hole via v23. One end of each of the third planar coil 3 and the tenth planar coil 10 is connected to the through-hole via v24. One end of each of the second planar coil 2 and the eleventh planar coil 11 is connected to the through-hole via v25. One end of each of the first planar coil 1 and the twelfth planar coil 12 is connected to the through-hole via v26. In this way, two planar coils each having a turn number of "1.5" are connected in series to form each coil portion, and the turn number of each coil portion becomes "3". In the following description, the first turn of each coil portion is also referred to as the "first turn T1", the second turn as the "second turn T2", and the third turn as the "third turn T3". In the present embodiment, the "coil width" means the width of the entire group of wire elements constituting each turn, and more specifically, the distance between the inner end of the innermost wire element in the planar direction and the outer end of the outermost wire element in the planar direction among the group of wire elements constituting each turn. Also, in the first turn T1 and the third turn T3, the central positions Ct21 of the coil widths of each turn coincide with each other. Also, the central position of the coil width of the second turn T2 is the central position Ct22.

[0059] The first coil layer S21 includes a connection terminal portion t21. The second coil layer S22 includes a connection terminal portion t22. The other ends of the first planar coil 1, the second planar coil 2, the third planar coil 3, the fourth planar coil 4, the fifth planar coil 5, and the sixth planar coil 6 are connected to the connection terminal portion t21. The other ends of the seventh planar coil 7, the eighth planar coil 8, the ninth planar coil 9, the tenth planar coil 10, the eleventh planar coil 11, and the twelfth planar coil 12 are connected to the connection terminal portion t22. The connection terminal portion t21 and the connection terminal portion t22 are exposed on the -Z direction end face and the +Z direction end face of the coil assembly 102, and are connected to the power transmission device 200 via a capacitor (not shown).

[0060] In FIG. 13, the XIII-XIII cross section in FIG. 12 is shown. As shown in FIG. 13, in the present embodiment, the wire sets of the wires of the third planar coil 3 and the fourth planar coil 4, which are two wire sets located inside in the width direction in each of the first turn T1 and the second turn T2, are arranged such that the pitch between the respective wires is the second pitch p2, and corresponds to the second pitch wire set. Similarly, the wire sets of the wires of the ninth planar coil 9 and the tenth planar coil 10, which are two wire sets located inside in the width direction in the third turn T3, are arranged such that the pitch between the respective wires is the second pitch p2, and corresponds to the second pitch wire set. In the present embodiment, "inside in the width direction" means a region where the distance from the central position Ct21 is closer in the first turn T1 and the third turn T3, and means a region where the distance from the central position Ct22 is closer in the second turn T2.

[0061] On the other hand, in each of the first turn T1 and the second turn T2, the wire sets of the first planar coil 1 and the second planar coil 2, which are two wire sets located outside the width direction from the wire set of the wire of the third planar coil 3 and the wire of the fourth planar coil 4, the wire set of the wire of the second planar coil 2 and the wire of the third planar coil 3, the wire set of the wire of the fourth planar coil 4 and the wire of the fifth planar coil 5, and the wire set of the wire of the fifth planar coil 5 and the wire of the sixth planar coil 6 are each arranged such that the pitch between the respective wires is the first pitch p1 and corresponds to the first pitch wire set. Similarly, in the third turn T3, the wire sets of the seventh planar coil 7 and the eighth planar coil 8, which are two wire sets located outside the width direction from the wire set of the wire of the ninth planar coil 9 and the wire of the tenth planar coil 10, the wire set of the wire of the eighth planar coil 8 and the wire of the ninth planar coil 9, the wire set of the wire of the tenth planar coil 10 and the wire of the eleventh planar coil 11, and the wire set of the wire of the eleventh planar coil 11 and the wire of the twelfth planar coil 12 are each arranged such that the pitch between the respective wires is the first pitch p1 and corresponds to the first pitch wire set. In the present embodiment, "outside in the width direction" means a region where the distance from the central position Ct21 is farther in the first turn T1 and the third turn T3, and means a region where the distance from the central position Ct22 is farther in the second turn T2.

[0062] As shown in FIG. 12, the housing 120 includes a plurality of support columns 121 that are arranged at equal intervals along the X-axis direction and the Y-axis direction respectively, and as shown in FIG. 13, has a plurality of support columns 121 that extend along the Z direction respectively. The housing 120 houses the first coil layer S21 and the second coil layer S22. More specifically, within the housing 120, the first coil layer S21 is arranged and housed such that the support columns 121 are positioned between the wires of the third planar coil 3, which are the wires constituting the second pitch wire group in each of the first turn T1 and the second turn T2, and the wires of the fourth planar coil 4. Since the interval between the wires constituting the second pitch wire group is larger than the interval between the wires constituting the first pitch wire group, it is easier to arrange the support columns 121 compared to the interval between the wires constituting the first pitch wire group. Similarly, the second coil layer S22 is arranged and housed such that the support columns 121 are positioned between the wires of the ninth planar coil 9, which are the wires constituting the second pitch wire group in the third turn T3, and the wires of the tenth planar coil 10. In FIGS. 12 and 13, the illustration of the magnetic body 110 and the shield member 112 is omitted.

[0063] According to the coil assembly 102 of the third embodiment described above, the same effects as those of the first embodiment are achieved. In addition, the coil assembly 102 further includes a housing 120 having support columns 121 that extend along the stacking direction, and each of the coil layers S21 and S22 housed in the housing 120 is arranged such that the support columns 121 are positioned between the wires constituting the second pitch wire group. Therefore, the interval for arranging the plurality of support columns 121 in the space within the housing 120 can be reduced compared to the form in which the support columns 121 are provided for each turn of the wire group, so that the strength against an external force applied to the housing 120 along a direction parallel to the stacking direction can be improved, and the coil layer can be protected from the external force.

[0064] Also, since the interval between the wires constituting the second pitch wire group is larger than the interval between the wires constituting the first pitch wire group, it is easier to arrange the support columns 121 between the wires constituting the second pitch wire group compared to the interval between the wires constituting the first pitch wire group.

[0065] D. Other Embodiments: (D1) In the above embodiment, in the plurality of first pitch wire sets, the pitch between the wires constituting each first pitch wire set is the first pitch p1 and is the same for each other, but the present disclosure is not limited thereto. The pitch between the wires constituting each first pitch wire set may be any pitch smaller than the second pitch p2. Such a form also has the same effect as the above embodiment.

[0066] Also, in the above embodiment, in the plurality of second pitch wire sets, the pitch between the wires constituting each second pitch wire set is the second pitch p2 and is the same for each other, but the present disclosure is not limited thereto. The pitch between the wires constituting each second pitch wire set may be any pitch larger than the first pitch p1. Such a form also has the same effect as the above embodiment.

[0067] (D2) In the above third embodiment, in each of the first turn T1 and the second turn T2, the wire set of the wire of the second planar coil 2 and the wire of the third planar coil 3, and the wire set of the wire of the fourth planar coil 4 and the wire of the fifth planar coil 5 are configured as a first pitch wire set having the first pitch p1, but the present disclosure is not limited thereto. The wire set of the wire of the second planar coil 2 and the wire of the third planar coil 3, and the wire set of the wire of the fourth planar coil 4 and the wire of the fifth planar coil 5 may be configured as a second pitch wire set having the second pitch p2. Similarly, in the third turn T3, the wire set of the wire of the eighth planar coil 8 and the wire of the ninth planar coil 9, and the wire set of the wire of the tenth planar coil 10 and the wire of the eleventh planar coil 11 may be configured as a second pitch wire set having the second pitch p2 instead of a first pitch wire set having the first pitch p1. Such a form also has the same effect as the above embodiment.

[0068] (D3) In the above-described third embodiment, the support column 121 is provided between the strands constituting the second pitch strand group, but the present disclosure is not limited thereto. The support column 121 may be provided between the strands constituting the first pitch strand group. Even in such a form, compared with the form without the support column 121, the strength against an external force applied to the housing 120 along the direction parallel to the stacking direction can be improved, and the coil layer can be protected from the external force.

[0069] (D4) In the above embodiment, each of the plurality of coil layers has the first pitch strand group and the second pitch strand group, but the present disclosure is not limited thereto. As long as at least a part of the plurality of coil layers has the first pitch strand group and the second pitch strand group, in other coil layers, the pitches between the strands constituting the coil layer may all be the same. Even in such a form, compared with the form in which the pitches between the strands constituting each coil layer are all the same in all of the plurality of coil layers, the bias of the current can be suppressed.

[0070] (D5) In the above embodiment, each of the plurality of coil layers is constituted by an odd-numbered planar coil, or each of the plurality of coil layers is constituted by an even-numbered planar coil, but the present disclosure is not limited thereto. For example, in a form in which the coil assembly has four coil layers, among the four coil layers, each of two coil layers may be constituted by an even-numbered planar coil, and each of the other two planar coils may be constituted by an odd-numbered planar coil. Even in such a form, the same effects as those of the above embodiment can be achieved.

[0071] (D6) In the above embodiment, each coil layer is constituted by sandwiching an insulator such as prepreg between the coil patterns of the planar coil made of copper foil, but the present disclosure is not limited thereto. Each coil layer may be constituted by winding litz wire. Even in such a form, the same effects as those of the above embodiment can be achieved.

[0072] (D7) In each embodiment, in the two coil layers, the central position of the coil width of each turn in one coil layer coincides with the central position of the coil width of each turn in the other coil layer, but the present disclosure is not limited thereto. The central position of the coil width of each turn in one coil layer may be located farther from the central axis of each coil layer than the central position of the coil width of each turn in the other coil layer. Even in such a configuration, the same effects as those of the above embodiments can be achieved.

[0073] (D8) The coil assemblies 100 to 103 of each embodiment are merely examples and may be variously modified. For example, in each of the coil layers S1, S2, S11, S12, S21, and S22, the planar shape (the shape when viewed in the Z direction) may not be rectangular as in each embodiment, and may be, for example, circular, elliptical, or a rectangular shape with R provided at the four corners. Further, the number of coil layers is not limited to 2 and may be any plurality of numbers.

[0074] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in each embodiment corresponding to the technical features in the forms described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted. (Form 1) A coil assembly (100, 101, 102), Comprising a plurality of coil layers (S1, S2, S11, S12, S21, S22) laminated in the stacking direction, each of the plurality of coil layers having a plurality of planar coils (1 to 8, 1 to 10, 1 to 12) wound in a planar direction intersecting the stacking direction and connected in parallel to each other, The plurality of coil layers are a plurality of coil portions (a to d, a to e) each constituted by at least one of the planar coils, and constitute a plurality of coil portions connected in parallel to each other, At least some of the plurality of coil layers include a first pitch strand set in which the pitch between adjacent strands is a first pitch, and a second pitch strand set in which the pitch between adjacent strands is a second pitch greater than the first pitch. The first pitch strand set is located on the outer side in the width direction of the coil width of the coil layer, rather than the second pitch strand set. Coil assembly. (Form 2) The coil assembly according to Form 1, The distance between the strands constituting the second pitch strand set is greater than the distance between the strands constituting the first pitch strand set. Coil assembly. (Form 3) The coil assembly according to Form 2, A housing (120) that houses the plurality of coil layers, further comprising a housing having a support column (121) extending in the stacking direction. The plurality of coil layers are arranged such that the support column is positioned between the strands constituting the second pitch strand set. Coil assembly. (Form 4) In the coil assembly according to any one of Forms 1 to 3, Each of the coil portions is configured by connecting in series the planar coils respectively included in two or more of the coil layers. The two or more planar coils constituting each of the coil portions include a planar coil wound radially inward in one of the coil layers and a planar coil wound radially outward in another of the coil layers. Coil assembly. (Form 5) The coil assembly according to any one of Forms 1 to 4, The number of the planar coils constituting at least some of the plurality of coil layers is an even number. The second pitch strand set is constituted by two strands closest to the central position of the coil width. Coil assembly. (Form 6) In the coil assembly according to any one of Forms 1 to 5, the sum of the self-inductance and the mutual inductance between the coil portions is equal to each other, Coil assembly.

Explanation of Signs

[0075] 1 to 8, 1 to 10, 1 to 12... planar coils, 100, 101, 102... coil assemblies, S1, S11, S21... first coil layer, S2, S12, S22... second coil layer, a to d, a to e... coil portions, p1... first pitch, p2... second pitch

Claims

1. A coil assembly (100, 101, 102), comprising: A plurality of coil layers (S1, S2, S11, S12, S21, S22) laminated in a lamination direction, each coil layer having a plurality of planar coils (1-8, 1-10, 1-12) wound in a planar direction intersecting the lamination direction and connected in parallel to each other; The plurality of coil layers are a plurality of coil portions (a-d, a-e) each constituted by at least one of the planar coils, and constitute a plurality of coil portions connected in parallel to each other; At least some of the plurality of coil layers include a first pitch wire set in which the pitch between adjacent strands is a first pitch, and a second pitch wire set in which the pitch between adjacent strands is a second pitch greater than the first pitch; The first pitch wire set is located outside the width direction of the coil width of the coil layer, relative to the second pitch wire set; Coil assembly.

2. The coil assembly according to claim 1, wherein: The distance between the wires constituting the second pitch wire set is greater than the distance between the wires constituting the first pitch wire set; Coil assembly.

3. The coil assembly according to claim 2, further comprising: A housing (120) for accommodating the plurality of coil layers, the housing having a support column (121) extending in the lamination direction; The plurality of coil layers are arranged such that the support column is located between the wires constituting the second pitch wire set; Coil assembly.

4. In the coil assembly according to any one of claims 1 to 3, Each of the coil portions is constituted by connecting in series the planar coils respectively included in two or more of the coil layers; The two or more planar coils constituting each of the coil portions include a planar coil wound radially inward in one of the coil layers and a planar coil wound radially outward in another of the coil layers; Coil assembly.

5. The coil assembly according to any one of claims 1 to 3, wherein: The number of the planar coils constituting at least some of the plurality of coil layers is an even number; The second pitch wire set is constituted by two wires closest to the central position of the coil width; Coil assembly.

6. In the coil assembly according to any one of claims 1 to 3, the sum of the self-inductance and the mutual inductance between the coil portions is equal to each other, coil assembly.

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