JP2012164728A - Coil component and power reception device and power supply device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component capable of dividing the current path of eddy current in a magnetic sheet while avoiding complication of the production process.SOLUTION: In the coil component comprising a coil, and a magnetic sheet opposed in the winding axial direction of the coil, the magnetic sheet is provided with a first slit in the principal surface thereof. When viewed from the winding axial direction of the coil, the first slit overlaps the coil only in one place. In a part where the first slit overlaps the coil, the longitudinal direction of the first slit is orthogonal to the winding direction of the coil.

Description

  The present invention relates to a coil component that can be widely applied to applications that require a coil and a magnetic shield, applications that require a coil and a yoke, and the like. For example, it is suitably used in a non-contact charging system that enables charging in a non-contact state by a primary transmission coil and a secondary transmission coil.

  In recent years, small information communication devices have been improved in performance and functionality, and in particular, portable devices such as mobile phones, web terminals, music players, etc. are required to be used continuously for a long time. Yes. In these small information communication devices, a secondary battery such as a lithium ion battery is used as a power source. This secondary battery charging method uses a contact charging method in which charging is performed by directly contacting the electrode on the power receiving side and the electrode on the power feeding side, and transmission coils are provided on both the power feeding side and the power receiving side, and electromagnetic induction is used. There is a non-contact charging method in which charging is performed by power transmission. Since the contactless charging method does not require an electrode for directly contacting the power feeding device and the power receiving device, it is possible to charge different power receiving devices using the same power feeding device. In addition, the non-contact charging method has an advantage that the problem of electrode corrosion and the problem of poor contact between electrodes can be avoided.

  In the non-contact charging method, the magnetic flux generated in the primary transmission coil is fed by generating an electromotive force in the secondary transmission coil through the housing of the power feeding device and the power receiving device. However, since sufficient transmission efficiency cannot be obtained with only this transmission coil, a magnetic sheet is provided on the opposite side of the transmission coil from the contact surface of the power feeding device and the power receiving device. In a coil component including a coil and a magnetic sheet, the magnetic sheet has the following role. The first role is a role as a magnetic shield material. When leakage magnetic flux generated during the charging operation of the non-contact charging device flows to other components such as a metal member constituting the secondary battery, these components generate heat due to eddy current. The magnetic sheet can suppress this heat generation as a magnetic shield material. The second role of the magnetic sheet is to act as a yoke member that recirculates the magnetic flux generated in the coil during charging.

  As a specific example of a coil component including a coil and a magnetic sheet, for example, Patent Document 1 discloses a power receiving device in which a magnetic foil body is disposed between a spiral coil and a secondary battery. In particular, Patent Document 1 also attempts to suppress eddy currents in the magnetic foil body by using a magnetic foil body having slits as shown in FIGS.

WO2007 / 080820

However, for example, when the magnetic foil body having the slits disclosed in FIGS. 10 to 12 of Patent Document 1 is formed by bonding the magnetic alloy ribbon and the flexible base material, it is processed into various shapes. Many pieces of magnetic metal ribbons must be arranged side by side on a flexible base material, which greatly complicates the manufacturing process. Furthermore, even when using a magnetic foil having a slit disclosed in FIGS. 13 and 14 of Patent Document 1, it is difficult to handle while maintaining the outer shape, so the manufacturing process is still complicated. Become. Further, in the configuration disclosed in Patent Document 1, a slit for dividing a current path of an eddy current due to a magnetic flux generated by a part of a coil (for example, one side of a rectangular coil) is simultaneously formed in another part of the coil ( For example, since the ratio of cutting the magnetic path of the magnetic flux generated by a side perpendicular to one side of the rectangular coil is large, there is a problem that the magnetic permeability is unexpectedly reduced in addition to the reduction of eddy current loss.

  In view of these points, the present invention avoids complication of the manufacturing process in a coil component including a coil and a magnetic sheet disposed in the winding axis direction of the coil, and the eddy current in the magnetic sheet is reduced. An object is to provide a coil component capable of dividing a current path.

  The coil component of the present invention is a coil component comprising a coil and a magnetic sheet opposed to the coil in the winding axis direction, the magnetic sheet comprising a first slit in its main surface, The first slit overlaps with the coil at only one position when viewed from the winding axis direction of the coil, and the longitudinal direction of the first slit is the portion where the first slit and the coil overlap. It is a direction orthogonal to the winding direction of the coil. According to such a configuration, while maintaining the strength of the magnetic sheet, the current path of the eddy current can be efficiently divided to reduce the loss.

  In the coil component, the first slit is provided as a pair, and the paired slits are arranged symmetrically about the winding axis of the coil when viewed from the winding axis direction of the coil. Is preferred. Such a configuration is effective from the viewpoint of strength balance of the entire magnetic sheet.

  In the coil component, it is preferable that the first slit is disposed so as not to protrude from the coil when viewed from the winding axis direction of the coil. According to such a configuration, the current path of the eddy current can be divided while suppressing the slit from becoming a magnetic resistance.

  Furthermore, in the coil component, the magnetic sheet preferably includes a second slit whose longitudinal direction is a winding direction of the coil. The effective permeability can be adjusted by using the second slit.

  Furthermore, in the coil component, it is preferable that the second slit is disposed so as not to protrude from the coil when viewed from the winding axis direction of the coil.

  Furthermore, in the coil component, it is preferable that the first slit has a burr at a peripheral portion thereof, and the protrusion of the burr is disposed so as to protrude on the opposite side to the coil.

  The power receiving device of the present invention includes the coil component. Transmission loss can be improved by using the coil component.

  A power supply device according to the present invention includes the coil component. Transmission loss can be improved by using the coil component.

    According to the present invention, in a coil component including a coil and a magnetic sheet arranged in the winding axis direction of the coil, the manufacturing process is prevented from being complicated and the influence on characteristics such as magnetic permeability is suppressed. In addition, it is possible to provide a coil component capable of dividing an eddy current path in the magnetic sheet, and a power receiving device and a power feeding device using the coil component.

It is a figure which shows the electric power feeder and power receiving apparatus which comprise a non-contact charging device. It is a figure which shows embodiment of the coil components of this invention. It is a figure which shows other embodiment of the coil components of this invention. It is a figure which shows other embodiment of the coil components of this invention. It is a figure which shows other embodiment of the coil components of this invention. It is a figure which shows the form of the magnetic sheet used for the Example.

    Hereinafter, embodiments of a coil component, a power feeding device, and a power receiving device according to the present invention will be specifically described with reference to the drawings. However, the present invention is not limited thereto. Moreover, the structure demonstrated in each embodiment is applicable also in other embodiment, unless the meaning of other embodiment is impaired, In that case, the overlapping description is abbreviate | omitted suitably.

  FIG. 1 is a cross-sectional view showing a non-contact charging device configured using a power feeding device and a power receiving device. A specific example of the non-contact charging device is, for example, a mobile communication terminal and its charger. The power feeding device and / or the power receiving device includes the coil component according to the present invention. The power receiving device also includes an electronic device body having a power receiving function such as a portable terminal. The power feeding device 10 connected to the AC power source 6 has a circuit unit 7. The circuit unit 7 includes a rectifier circuit that rectifies an alternating current and a switching circuit that converts the rectified direct current into a high-frequency current having a predetermined frequency. The high-frequency current output from the circuit unit 7 flows through the coil 3a which is a primary transmission coil. The coil 3a is connected to a resonance capacitor (not shown) and resonates at the same frequency as the predetermined frequency converted by the switching circuit. The power supply apparatus 10 may be provided with a control circuit for controlling the operation of the switching circuit.

  The power receiving apparatus 11 includes a coil 3b that is a secondary transmission coil. A resonance circuit can be configured by arranging a resonance capacitor. The coil 3b is connected to the secondary battery 5 via a rectifier circuit (not shown), and the induced current induced in the coil 3b by electromagnetic induction is rectified by the rectifier circuit, and the secondary battery 5 is charged. The

  The power feeding device 10 and the power receiving device 11 are accommodated in a nonmagnetic housing such as resin. Each of the casings has a flat surface, and charging is performed with the flat surfaces facing each other. The power feeding device and the charging device are positioned and fixed to each other using fixing means such as a magnet. The coils 3a and 3b are arranged inside the housing so that the winding axis thereof is perpendicular to the flat surface (the surface of the planar coil is parallel to the flat surface). On the opposite side of the flat surface of the coils 3a and 3b, magnetic sheets 1a and 1b are respectively arranged adjacent to each other. Inside the housing, for example, substrates 8a and 8b such as resin substrates are arranged. The magnetic sheets 1a and 1b are arranged between the substrates 8a and 8b on which the secondary battery 5 and the like are installed and the coils 3a and 3b so that their main surfaces overlap or cover the coils 3a and 3b. Therefore, the magnetic flux generated by the coils 3a and 3b converges and passes through the magnetic sheets 1a and 1b, and the magnetic sheet functions as a magnetic yoke or a magnetic shield. The coil parts 9a and 9b including the coils 3a and 3b and the magnetic sheets 1a and 1b facing each other in the winding axis direction of the coil will be specifically described below.

(First embodiment)
FIG. 2 is a plan view of a coil component including a planar coil and a planar magnetic sheet as viewed from the normal direction of the planar sheet surface (main surface). (A) shows a magnetic sheet, and (b) shows a coil component in which a magnetic sheet is opposed to a coil. The magnetic sheet may be a single magnetic substance or may be a laminate of a plurality of sheet-like magnetic substances with an insulating layer interposed therebetween. In the embodiment shown in FIG. 2, the rectangular magnetic sheet 21 includes two linear first slits 22 in the main surface. The provision of the first slit “in the main surface” means that both longitudinal ends of the first slit do not reach the edge of the magnetic sheet. The width in the direction perpendicular to the longitudinal direction of the slit may be set to a size sufficient for separating the magnetic bodies from each other, for example, 0.1 mm or more. Even if the width of the slit is increased more than necessary, the effect of reducing the loss does not increase accordingly. In addition, the magnetic body which comprises the magnetic sheet may have a crack, and the crack from the said slit may have reached the magnetic sheet edge. Even in such a configuration, the crack in which the magnetic material is not completely separated from the slit of the present invention can be clearly distinguished, and the effect as the slit described later is also exhibited. The sheet is still provided with a first “slit” in its “main surface”. However, it is more preferable that there is no crack reaching the edge of the magnetic sheet from the slit.

  The coil 23 shown in FIG. 2 (b) is composed of a winding wound in a rectangular shape. The form of the coil is not limited to this, and for example, it may be wound in a circle as in the embodiment described later, or may be a polygon or other irregular shape. The coil is a planar coil having a dimension (outer diameter dimension) in the direction perpendicular to the thickness dimension in the coil winding axis direction, but the winding method is also particularly limited. It is not a thing. For example, a flat spiral coil formed by one stage of winding on a plane may be used, or the winding may be composed of two or more stages. In addition to the wire, the coil may be formed using a thin film or printing. In the embodiment shown in FIG. 2, the vertical and horizontal dimensions of the magnetic sheet 21 are larger than that of the coil 23 so that the magnetic sheet 21 covers the entire coil 23. Each of the two first slits 22 overlaps with the coil 23 only at one position when viewed from the winding axis direction of the coil 23 (corresponding to a direction perpendicular to the xy plane in FIG. 2). It should be noted that overlapping with the coil only at one point is intended to eliminate a configuration in which one slit overlaps the coil on both sides of the hollow portion at the center of the coil, It is not a problem of overlapping. In each portion where the first slit 22 and the coil 23 overlap, the longitudinal direction of the first slit 22 is orthogonal to the winding direction of the coil 23 (winding extension direction).

  The direction of the magnetic flux generated in the magnetic sheet by the portion having the longitudinal direction (y direction) of the rectangular / frame-shaped coil 23 as the winding direction is substantially parallel to the longitudinal direction of the first slit 22. Therefore, the eddy current due to the magnetic flux applied by the first slit 22 can be suppressed. On the other hand, the portion of the first slit that protrudes from the coil 23 is perpendicular to the magnetic flux generated in the magnetic sheet by the portion of the rectangular / frame-shaped coil 23 whose transverse direction (x direction) is the winding direction. The positional relationship is easy to act as a magnetic resistance. However, in the embodiment shown in FIG. 2, each of the two first slits 22 overlaps with the coil 23 only at one place when viewed from the winding axis direction of the coil 23, so the slits overlap at two places. Compared to the case (e.g., corresponding to a configuration in which the two first slits 22 in FIG. 2 are connected by a hollow portion), the portion that acts as a magnetic resistance is relatively reduced. Therefore, it is possible to mitigate unexpectedly low effective magnetic permeability. Furthermore, since the first slit 22 that exhibits the above effect is formed in the main surface of the magnetic sheet 21, a decrease in strength of the magnetic sheet is suppressed as compared with a configuration in which the slit reaches the edge of the magnetic sheet. This contributes to improved handling of the magnetic sheet. If at least one first slit is provided in the “main surface” of the magnetic sheet, the effect of suppressing the decrease in the strength of the magnetic sheet can be obtained. In addition, a slit reaching the edge of the magnetic sheet is provided. May be. However, in order to maximize the effect, it is preferable that all the slits are formed in the main surface of the magnetic sheet. In addition, the structure itself in which all the slits are formed in the main surface of the magnetic sheet can be widely applied as a structure for ensuring the strength of the magnetic sheet on which the slit is formed, regardless of the structure related to the direction of the slit.

  In the embodiment shown in FIG. 2, the first slit is arranged at the center of the vertical portion of the coil 23, but the position may be shifted in the vertical direction, or the two slits may be It may be stepped in the vertical direction. However, the first slits 22 are provided as a pair, and the pair of slits 22 is seen from the direction of the winding axis of the coil 23. A configuration in which the magnetic sheet 21 is symmetrically arranged with respect to the center is advantageous from the standpoint of maintaining the overall strength balance of the magnetic sheet 21 and reducing characteristic variations. As such a symmetrical arrangement, as shown in FIG. 2, a configuration in which a pair of slits are arranged on one straight line is more preferable. As a result, this configuration is positioned at the center in the longitudinal direction of the coil 23, and even if there is a portion protruding from the coil 23 in the first slit, the portion in which the winding direction is the transverse direction is the magnetic sheet. The influence of the portion on the magnetic flux generated inside can be minimized.

  In the embodiment shown in FIG. 2, two first slits are provided, but there may be one first slit or three or more first slits. However, from the viewpoint of reducing the strength balance and characteristic variation of the magnetic sheet, a plurality is preferable. In addition, the magnetic sheet of the coil component according to the present invention can have various configurations such as a rectangle such as a square and a rectangle, a circle, a ring shape, an irregular shape, and a shape with irregularities formed thereon. In addition, since a magnetic sheet having an opening inside the magnetic body, such as a ring shape, is disadvantageous in terms of the half surface that is easy to position and the like, and in terms of strength, the present invention is used when forming a slit in the ring-shaped magnetic sheet. The slit structure according to is particularly effective. Hereinafter, an embodiment in which the magnetic sheet or the like is circular will be described.

(Second Embodiment)
FIG. 3 shows an embodiment using a circular magnetic sheet and an annular coil as another embodiment of a coil component including a planar coil and a planar magnetic sheet. FIG. 3 is a plan view seen from the normal direction of the plane. (A) shows a magnetic sheet, and (b) shows a coil component in which a magnetic sheet is opposed to a coil. The annular coil 33 and the circular magnetic sheet 31 are arranged concentrically, and their centers coincide. In the embodiment shown in FIG. 3, the circular magnetic sheet 31 includes four linear first slits 32 in its main surface. The longitudinal direction of the first slit 32 is a direction extending radially from the center of the circular magnetic sheet 31 (which is also the center of the annular coil 33), and the four first slits 32 each have a central angle of 90 degrees. Arranged at the pitch. Considering two sets of pairs, the slits 32 forming the respective pairs are seen from the winding axis direction of the coil 33, and the winding axis of the coil 33 (at the intersection of the auxiliary lines indicated by the one-dot chain line in FIG. 3). It can also be said that it is arranged symmetrically with respect to (shown). Each of the four first slits 32 overlaps with the coil 33 only at one position when viewed from the winding axis direction of the coil 33 (corresponding to a direction perpendicular to the xy plane in FIG. 3). In addition, in each portion where the first slit 32 and the coil 33 overlap, the longitudinal direction of the first slit 32 is a direction orthogonal to the winding direction of the coil 33 (winding extension direction). This is the same as the first embodiment shown in FIG.

  The magnetic sheet 31 includes a first slit 32 in its main surface, and the first slit 32 overlaps with the coil 33 only at one place when viewed from the winding axis direction of the coil 33 and the first slit 32. In the portion where the coil 33 and the coil 33 overlap, the effect of the configuration in which the longitudinal direction of the first slit 32 is perpendicular to the winding direction of the coil 33 is as described in the first embodiment. In the embodiment shown in FIG. 3, since more slits are provided as the first slit, the effect of dividing the current path of the eddy current is greater. The number of first slits is not limited to four. Three or more may be added. When the coil is annular, the circumferential positions of the radially arranged slits are equivalent, and the number of slits can be easily increased. In that case, it is preferable to arrange the slits at equal pitches at the central angle.

(Third embodiment)
FIG. 4 shows another embodiment using a circular magnetic sheet and an annular coil. FIG. 4 is a plan view seen from the normal direction of the plane of the magnetic sheet or the like. 4A shows a magnetic sheet, and FIG. 4B shows a coil component in which a magnetic sheet is placed on a coil. The third embodiment shown in FIG. 4 is different from the embodiment shown in FIG. 3 in the configuration related to the shape of the first slit. Specifically, the dimension of the first slit 42 formed in the magnetic sheet 41 is shortened. Other parts are the same as those of the second embodiment shown in FIG. In the embodiment shown in FIG. 4, the first slit 42 is disposed so as not to protrude from the coil 43 when viewed from the winding axis direction of the coil 43. When there is a portion where the slit protrudes from the coil as in the first embodiment shown in FIG. 2 or the second embodiment shown in FIG. 3, this portion is a part of the magnetic flux generated by the other portion of the coil. It becomes a magnetoresistance with respect to a component which is not parallel to it. On the other hand, according to the configuration shown in FIG. 4, since the magnetic flux around the slit is a radial magnetic flux along the longitudinal direction of the slit, the magnetic flux crosses the slit, that is, the slit becomes a magnetic resistance. Can be suppressed. Moreover, it avoids that a slit becomes longer than necessary, and contributes also to the intensity | strength maintenance of a magnetic sheet.

(Fourth embodiment)
FIG. 5 shows another embodiment using a circular magnetic sheet and an annular coil. FIG. 5 is a plan view seen from the normal direction of the plane of the magnetic sheet or the like. FIG. 5A shows a magnetic sheet, and FIG. 5B shows a coil component in which a magnetic sheet is placed on a coil. The fourth embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 4 in that the magnetic sheet 51 includes a second slit 54 whose longitudinal direction is the winding direction of the coil 53. In the embodiment shown in FIG. 5, since the coil 53 is an annular coil, the winding direction of the coil 53 is a circumferential direction centering on the winding axis of the coil, and the second slit 54 is arcuate. It is. The second slits 54 are disposed between the first slits, and are disposed at a pitch of 90 degrees at the central angle, like the first slits. While the current path of the eddy current is divided by the first slit 52, the effective permeability can be adjusted and the magnetic saturation can be relaxed by the second slit 54. The second slit 54 may be arranged at a position shifted from the coil 53. However, in order to efficiently adjust the effective magnetic permeability while ensuring the strength of the magnetic sheet, the second slit 54 is used as shown in FIG. The second slit 54 is preferably arranged so as not to protrude from the coil 53 when viewed from the winding axis direction of the coil 53. In addition, when adjustment of the effective magnetic permeability by a slit is unnecessary, it is preferable not to provide the second slit and to prioritize current path division of eddy current.

  Next, the magnetic sheet used for the coil component will be described. As the soft magnetic material used for the magnetic sheet, ferrite, a silicon steel plate, a metal ribbon manufactured by roll quenching, a composite material of these with a resin, and the like can be used. In order to reduce eddy current loss and improve charge transmission efficiency, it is preferable to make the soft magnetic material thinner. In this respect, a metal ribbon manufactured by roll quenching among the soft magnetic materials is particularly preferable. Specifically, a metal ribbon having a thickness of 50 μm or less made of an Fe-based amorphous material, a Co-based amorphous material, an Fe-based nanocrystalline material, a Co-based nanocrystalline material, or the like having a high saturation magnetic flux density may be used. The thickness of the metal ribbon is more preferably 30 μm or less, and further preferably 20 μm or less.

  As the magnetic sheet, a thin soft magnetic material may be used as it is, but it is preferably fixed to the reinforcing member in order to prevent breakage. Specifically, it is preferable to use a magnetic sheet obtained by laminating a metal ribbon with a resin sheet or the like. Only one magnetic sheet may be used, but a plurality of layers may be stacked via a resin sheet. The total thickness of all the soft magnetic materials used in the magnetic sheet can be 150 μm or less, and further 100 μm or less. It is also possible to constitute a thin one having a thickness of 50 μm or less.

  The slit formed in the magnetic sheet may be formed by punching or cutting if a metal ribbon is used for the soft magnetic material. When laminating with a resin sheet as described above, slits may be formed before laminating, or slits may be formed after laminating. If slits are formed before laminating, no slits are formed in the resin, so that the strength as a magnetic sheet can be maintained high. On the other hand, the method of forming slits after laminating contributes to simplification of the process particularly when a plurality of metal ribbons are laminated. Furthermore, when laminating a plurality of metal ribbons, the position of the slit can be changed for each layer. According to such a configuration, it is possible to disperse a decrease in strength due to the formation of the slit, and it is also possible to prevent the opening of the magnetic body due to the formation of the slit. If ferrite is used as the soft magnetic material, it is preferable to provide a slit by punching, laser, or the like in the state of the formed body before sintering.

  When slits are formed in the magnetic sheet by the method as described above, the slits have not a few burrs at their peripheral portions. When a coil component is configured using such a magnetic sheet, disturbance of magnetic flux can be mitigated if the burr protrusion is arranged so as to protrude to the opposite side of the coil. Moreover, if the side where protrusions, such as a burr | flash, protruded is further covered with a resin sheet, the unevenness | corrugation by a protrusion of a burr | flash can be absorbed by resin.

  The coil component according to the present invention is not limited to the above-described non-contact charging power supply device and power receiving device, and can be widely applied to electronic devices including a coil and a magnetic yoke, and a coil and a magnetic shield.

  A coil component was configured using a magnetic sheet having a slit shape shown in FIG. FIG. 6A shows an annular magnetic sheet without slits, and FIGS. 6B, 6C, and 6D respectively show four, eight, and sixteen first slits radially. It is the formed annular | circular shaped magnetic sheet. A nanocrystalline material was used for the soft magnetic material of the magnetic sheet. Finemet (registered trademark) (FT3: thickness 18 μm) manufactured by Hitachi Metals, Ltd. was used as the nanocrystal material. A double-sided adhesive sheet (thickness: 10 μm) was attached to this nanocrystalline material to form a lamination sheet, and a sheet with a different number of lamination sheets was prepared. A PET resin having a thickness of 31 μm (including an adhesive layer) was attached to the nanocrystalline material exposed on the uppermost surface. The slits were formed at an equal pitch at the central angle. Further, (e) is a structure in which a second slit having a longitudinal direction in the coil winding direction is formed in the configuration of (b). The magnetic sheet had an outer diameter of 40 mm and an inner diameter of 25 mm, and both ends of each slit were positioned inward by 2 mm from the outer periphery and the inner periphery, respectively. The coil was formed by winding a litz wire having a wire diameter of 0.5 mm for 20 turns. The obtained coil had an outer diameter of 40 mm and an inner diameter of 20 mm. Accordingly, the outer shape (outer periphery) of the coil and the magnetic sheet coincide with each other, but the coil protrudes to the inner diameter side than the magnetic sheet. In this way, all the radially formed slits were arranged so as not to protrude from the coil. The second slit (e) was formed at a position 15 mm from the center of the magnetic sheet, and both ends in the longitudinal direction were separated from the first slit by about 2 mm. The width in the direction perpendicular to the longitudinal direction of each slit was 0.3 to 0.5 mm. The magnetic sheet and the center of the coil were aligned to constitute a coil component, and the coil component was incorporated into a power receiving device and a power feeding device of a non-contact charging device, and the transmission efficiency was measured. Table 1 shows the evaluation results for the magnetic sheets (a) to (d).

  The magnetic sheets (b) to (d) in which the first slits are formed compared to the configuration using the magnetic sheet (a) in which the slits are not formed in the case where the three layers and the nine layers are stacked. It can be seen that the transmission efficiency is high in the configuration using. Further, under the condition of 9 layers in which the total thickness of the magnetic part is 100 μm or more, the transmission efficiency of the configuration using the magnetic sheets (c) and (d) in which 8 or more first slits are provided. Is high. In addition, the magnetic sheets (b) to (d) provided with the first slit maintained a sufficient strength that does not impair the handling property even when the coil component was constituted.

  The transmission efficiency was compared between the configuration using the magnetic sheet (b) provided with only the first slit and the configuration using the magnetic sheet (e) provided with the second slit. In order to facilitate the formation of slits and the formation of magnetic sheets, the transmission efficiency was evaluated with a small number of layers (3 layers and 6 layers).

  When 6 layers are stacked, the transmission efficiency of the configuration in which the second slit is provided is slightly lowered. However, when the number of layers is small as in the case of 3 layers, the transmission efficiency is improved by providing the second slit. It can be seen that it has improved. When the number of stacked layers is small, the magnetic sheet is likely to be saturated. Therefore, the provision of the second slit is considered to reduce the effective magnetic permeability and reduce the influence of saturation. In addition, the magnetic sheet (e) provided with the second slit maintained a sufficient strength that does not impair the handling property even when the coil component was formed.

DESCRIPTION OF SYMBOLS 1a, 1b: Magnetic sheet 3a, 3b: Coil 5: Secondary battery 6: AC power supply 7: Circuit part 8a, 8b: Board | substrate part 9a, 9b: Coil component 10: Power feeding apparatus 11: Power receiving apparatus 21, 31, 41, 51 : Magnetic sheet 22, 32, 42, 52: First slit 23, 33, 43, 53: Coil 54: Second slit

Claims (8)

A coil component comprising a coil and a magnetic sheet facing the winding axis direction of the coil,
The magnetic sheet includes a first slit in a main surface thereof,
The first slit overlaps with the coil at only one position when viewed from the winding axis direction of the coil,
The coil component, wherein a longitudinal direction of the first slit is a direction orthogonal to a winding direction of the coil in a portion where the first slit and the coil overlap.   The first slit is provided in a pair, and the pair of slits are arranged symmetrically about the winding axis of the coil when viewed from the winding axis direction of the coil. Item 2. The coil component according to Item 1.   3. The coil component according to claim 1, wherein the first slit is disposed so as not to protrude from the coil when viewed from a winding axis direction of the coil.   The said magnetic sheet is equipped with the 2nd slit which makes the winding direction of the said coil a longitudinal direction, The coil components as described in any one of Claims 1-3 characterized by the above-mentioned.   5. The coil component according to claim 4, wherein the second slit is disposed so as not to protrude from the coil when viewed from a winding axis direction of the coil.   The said 1st slit has a burr | flash in the peripheral part, The protrusion of the said burr | flash is arrange | positioned so that it may protrude on the opposite side to the said coil. The coil component according to the item.   A power receiving device comprising the coil component according to claim 1.     A power supply apparatus comprising the coil component according to claim 1.

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