JP6032528B2 - Transmission coil component and non-contact charging device - Google Patents

Description

  The present invention relates to a transmission coil component having a coil and a magnetic sheet functioning as a magnetic shield, a magnetic yoke, or the like. Furthermore, it is related with the non-contact charging device using it.

  In recent years, small electronic devices and information communication devices have been improved in performance and functionality. In particular, mobile phones, web terminals, music players, etc. are used continuously for a long time for convenience as portable devices. Is required to be possible. 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 order to obtain high power transmission efficiency, a coil yoke such as a magnetic sheet is installed on the opposite side of the transmission coil from the contact surface of the power feeding device and the power receiving device. The coil yoke 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 coil yoke can suppress this heat generation as a magnetic shield material. The second role of the coil yoke is to act as a yoke member for returning the magnetic flux generated in the coil during charging. For example, Patent Document 1 that discloses a cordless power station that transmits electric power in a non-contact manner by electromagnetic induction generated between coils discloses a configuration in which a soft magnetic ferrite plate is disposed as a soft magnetic material portion on the outside of the coil. Yes. In Patent Document 1, magnetic flux leakage is prevented by such a soft magnetic ferrite plate.

JP-A-7-231586

  For non-contact charging devices for electronic devices and information communication devices, there is a strong demand for downsizing, in particular reduction in thickness, as well as improvement in characteristics such as transmission efficiency. According to the configuration described in Patent Document 1, although it is expected to prevent magnetic flux leakage and improve transmission power and conversion efficiency, the soft magnetic material portion is provided, and soft magnetic ferrite is used as the soft magnetic material portion. Because it is used, it has not been able to sufficiently meet the demand for miniaturization and thinning.

  In view of this point, the present invention maintains a function of a magnetic sheet as a magnetic yoke or the like while suppressing a decrease in inductance and efficiency in a transmission coil component for a non-contact charging device including a coil and a magnetic sheet facing the coil. However, it aims at providing the structure which can be reduced in thickness. Furthermore, it aims at achieving size reduction of a non-contact charging device using this structure.

A transmission coil component for a non-contact charging device according to the present invention includes a coil and a magnetic sheet disposed so as to face the coil, and the magnetic sheet has a ferrite layer and a saturation magnetic flux density larger than that of the ferrite layer. A soft magnetic alloy ribbon having two or more soft magnetic alloy ribbons, wherein the ferrite layer is a Ni-Zn ferrite sintered body having a resistivity of 10 ⁵ Ω · m or more, and the ferrite layer is It arrange | positions so that it may become the said coil side. With this configuration, it is possible to reduce the thickness of the transmission coil component while suppressing a decrease in inductance and efficiency.

In the transmission coil component, it is preferable that the soft magnetic alloy ribbon layer has two or more soft magnetic alloy ribbons. By arranging the ferrite layer of the magnetic sheet so as to be on the coil side, an effect of suppressing the decrease in efficiency can be obtained, but the effect can be further enhanced by having two or more soft magnetic alloy ribbons. The soft magnetic alloy ribbon of the soft magnetic alloy ribbon layer is preferably a nanocrystalline soft magnetic alloy ribbon having a saturation magnetic flux density of 1.2 T or more.

  In addition, a power receiving device for a non-contact charging device according to the present invention includes the transmission coil component. By providing the above-described transmission coil component, it is possible to reduce the size of the power receiving device for the non-contact charging device.

  In addition, a power feeding device for a non-contact charging device according to the present invention includes the transmission coil component. By providing the transmission coil component described above, it is possible to reduce the size of the power feeding device for the non-contact charging device.

  Further, the non-contact charging device of the present invention is a non-contact charging device having a power feeding device and a power receiving device that are used facing each other, wherein the transmission coil component is provided in at least one of the power feeding device and the power receiving device. Features.

    According to the present invention, in a transmission coil component for a non-contact charging device including a coil and a magnetic sheet facing the coil, while suppressing a decrease in inductance and efficiency, while maintaining the function of the magnetic sheet as a magnetic yoke, A configuration capable of being thinned can be provided. Furthermore, it is possible to reduce the size of the non-contact charging device using such a configuration.

It is a figure which shows the non-contact charging device provided with the electric power feeder and the receiving device. It is a figure which shows the example of the magnetic sheet used for the transmission coil component which concerns on this invention. It is a figure which shows embodiment of the transmission coil component which concerns on this invention. It is a figure which shows other embodiment of the transmission coil component which concerns on this invention. It is a figure which shows the other example of the magnetic sheet used for the transmission coil component which concerns on this invention.

  Hereinafter, embodiments of the transmission coil component and the non-contact charging 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 having a power feeding device and a power receiving device that are used facing each other. Each of the power feeding device and the power receiving device includes transmission coil components, and transmits power between the transmission coil components with these transmission coil components facing each other. At least one of the power feeding device and the power receiving device includes the transmission coil component according to the present invention. Each transmission coil component includes a planar coil and a magnetic sheet disposed to face the coil. A specific example of the non-contact charging device is, for example, a mobile communication terminal and its charger. The power receiving device includes a battery unit alone in addition to an electronic device main body having a power receiving function such as a portable terminal.

  A power feeding device 12 connected to the AC power supply 10 includes a circuit unit 11. The circuit unit 11 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 power feeding device 12 includes a planar coil 7 and a magnetic attracting member 8 disposed inside the planar coil 7. The high-frequency current output from the circuit unit 11 flows through the planar coil 7 that is a primary transmission coil. The planar coil 7 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 feeding device 12 may be provided with a control circuit for controlling the operation of the switching circuit.

  The power receiving device 5 includes a planar coil 2 that is a secondary transmission coil, and a magnetic sheet 1 that is disposed on the rear surface side of the planar coil 2 as a coil yoke. The side facing the primary transmission coil is referred to as the front side, and the opposite side is referred to as the rear side. A resonance circuit can be configured by arranging a resonance capacitor in addition to the planar coil 2 as a secondary transmission coil. A secondary battery 4 is connected to the planar coil 2 via a rectifier circuit (not shown), and the induced current induced in the planar coil 2 by electromagnetic induction is rectified by the rectifier circuit. 4 is charged.

  The power feeding device 12 and the power receiving device 5 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 power receiving device are positioned and fixed to each other using the magnetic adsorption member 8 described above. At least one of the magnetic attracting member of the power feeding device and the magnetic attracting member of the power receiving device is configured using a magnet. For example, in the configuration shown in FIG. 1, the magnetic attracting member 8 of the power feeding device is a magnet or a magnetic yoke that induces a magnetic flux from the magnet. A magnet can also be provided and positioned and fixed on the power receiving device side, but the magnetic sheet 1 has a function as a magnetic attracting member on the power receiving device side having the configuration shown in FIG. That is, the magnetic attracting member 8 on the power feeding device side and the magnetic sheet 1 on the power receiving device side are arranged to face each other, and the power feeding device 12 and the power receiving device 5 are positioned and fixed by the magnetic attracting force between them. Is done.

  The planar coils 2 and 7 are arranged inside the casing 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 (rear surface side) of the planar coils 2 and 7 to the flat surface, magnetic sheets 1 and 6 are respectively disposed adjacent to each other. For example, substrates 3 and 9 such as a resin substrate are disposed inside the housing. Note that the configurations of the magnetic sheet and the magnetic adsorption member can be interchanged between the power receiving device and the power feeding device. However, since there is a strong demand for downsizing the power receiving device, it is more preferable not to use a configuration including a magnetic attracting member separate from the magnetic sheet on the power receiving device side. The magnetic sheet 6 on the power feeding device side may use a magnetic body having the same configuration as that of the magnetic sheet 1 on the power receiving side, but may have a different configuration. Further, the magnetic sheet 1 may be directly attached to the secondary battery 4 by omitting the power receiving side substrate 3. The magnetic sheets 1 and 6 are disposed so that the main surfaces thereof overlap or cover the planar coils 2 and 7 between the substrates 3 and 9 and the planar coils 2 and 7 on which the secondary battery 4 and the like are installed. Be placed. Accordingly, the magnetic flux generated by the planar coil 7 wound in a spiral shape converges and passes through the magnetic sheets 1 and 6, and the magnetic sheet functions as a magnetic yoke or a magnetic shield. The parts of the magnetic sheets 1 and 6 facing the winding axis direction of the planar coils 2 and 7 will be specifically described below.

(First embodiment)
An example of a magnetic sheet used for the transmission coil component according to the present invention is shown in FIG. 2, and an example of a transmission coil component for a non-contact charging device using such a magnetic sheet is shown in FIG. The transmission coil component shown in FIG. 3 is a transmission coil component used in the power receiving device 5 of the non-contact charging device shown in FIG. Fig.2 (a) is the top view which looked at the planar magnetic sheet from the normal line direction of the main surface. The magnetic sheet 1 shown in FIG. 2 has a rectangular outer shape, but the outer shape is not limited to this. For example, in addition to a rectangle such as a rectangle or a square, various configurations such as a circle, an ellipse, an irregular shape, and a shape with irregularities formed thereon can be employed. Further, in the rectangular configuration shown in FIG. 2, rounds are formed at the four corners, but such rounds may not be formed. FIG. 2B is a cross-sectional view of the planar magnetic sheet 1 viewed from a direction perpendicular to the normal line. The magnetic sheet 1 is a laminated sheet having a sheet-like ferrite layer 1a and a soft magnetic alloy ribbon 1b. The ferrite layer 1a and the soft magnetic alloy ribbon 1b are bonded together via an adhesive layer (not shown). In the configuration shown in FIG. 2, the outer shapes of the ferrite layer 1a and the soft magnetic alloy thin ribbon layer 1b are made the same and the outer periphery is made uniform, but these shapes and sizes may be different.

The ferrite layer 1a can be configured using various ferrite materials such as a Ni-based ferrite sintered body and a Mn-based ferrite sintered body. Ferrite materials have a higher resistivity than metal materials and are effective in reducing eddy current loss. Of the ferrite materials, a Ni—Zn ferrite sintered body having a resistivity of 10 ⁵ Ω · m or more and a high resistivity is more preferable. On the other hand, the soft magnetic alloy thin ribbon layer 1b is configured using a magnetic alloy thin ribbon manufactured by roll quenching. Soft magnetic alloy ribbon materials are, for example, Fe-based amorphous ribbons, Co-based amorphous ribbons, Fe-based nanocrystalline soft magnetic alloy ribbons, Co-based nanocrystalline soft magnetic alloy ribbons, etc., and saturation of 0.5 T or more It has a magnetic flux density and a relative magnetic permeability (at 100 kHz) of 3000 or more, and is more excellent in magnetic permeability and saturation magnetic flux density than the ferrite material constituting the ferrite layer 1a. Of these, microcrystalline soft magnetic alloy ribbons such as Fe-based nanocrystalline soft magnetic alloy ribbons are particularly preferred as magnetic materials constituting magnetic sheets because they have particularly high saturation magnetic flux density and magnetic permeability. For example, a Fe-based nanocrystalline soft magnetic alloy ribbon having a saturation magnetic flux density of 1.2 T or more and a relative magnetic permeability (at 100 kHz) of 10,000 or more is suitable. In order to reduce the eddy current loss and improve the charge transmission efficiency, it is preferable to make the soft magnetic material thin. Therefore, if the thickness of the soft magnetic alloy ribbon is 50 μm or less, more preferably 30 μm or less. Good.

  By bonding the ferrite layer 1a and the soft magnetic alloy thin ribbon layer 1b together, it is possible to make the magnetic sheet thinner as compared with the case where the magnetic sheet is constituted only by the ferrite layer. In the present invention, the ferrite layer 1a and the soft magnetic alloy thin ribbon layer 1b are not simply bonded together, but are arranged so that the ferrite layer 1a is on the planar coil 2 side as shown in FIG. The soft magnetic alloy ribbon 1b is disposed on the secondary battery 4 side when the transmission coil component is used in a power receiving device. By arranging the ferrite layer 1a so as to be on the planar coil 2 side, the transmission coil component has a higher Q value as compared with the case where the soft magnetic alloy ribbon layer 1b is located on the planar coil 2 side. It is obtained.

(Second Embodiment)
Another example of the transmission coil component according to the present invention is shown in FIG. In the embodiment shown in FIG. 4, the soft magnetic alloy ribbon 1b is composed of two layers of soft magnetic alloy ribbons (1b (1), 1b (2)). Different from the embodiment. Other configurations are the same as those of the embodiment shown in FIG. By making the soft magnetic alloy ribbon layer 1b into multiple layers, inductance is increased and magnetic saturation is difficult to occur. Furthermore, the above-described effect of arranging the ferrite layer 1a so as to be on the planar coil 2 side becomes even more remarkable. The plurality of soft magnetic alloy ribbons are laminated via a resin (not shown) as an adhesive layer. The soft magnetic alloy ribbon is not limited to two layers but may be more than that. As the number of soft magnetic alloy ribbons increases, the above effect becomes more prominent. The upper limit of the number of soft magnetic alloy ribbon layers is not particularly limited, but the process becomes complicated when the number of soft magnetic alloy ribbon layers increases. . Further, from the viewpoint of the characteristics and cost of the soft magnetic alloy ribbon capable of being thinned, it is preferable that the soft magnetic alloy ribbon layer does not have too many portions. For example, it is preferable that the total thickness of the soft magnetic alloy thin ribbon layer 1b excluding the nonmagnetic part such as the adhesive layer is smaller than the thickness of the ferrite layer 1a. It is possible to make the ferrite layer 1a into two or more layers. However, since the process becomes complicated, the ferrite layer 1a is preferably a single layer.

(Third embodiment)
The magnetic sheet used for the transmission coil component according to the present invention is not limited to a solid simple shape as shown in FIG. 2, and may have an opening, a notch, or the like. Another example of the magnetic sheet used for the transmission coil component according to the present invention is shown in FIG. FIG. 5 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. Since the shape of a plane is different from the embodiment shown in FIG. 2 and other configurations are the same, the description thereof is omitted. The magnetic sheet 13 shown in FIG. 5 has a substantially rectangular outer shape and has an annular opening 14. Further, the magnetic sheet 13 has a portion 15 surrounded by the opening 14. Hereinafter, the part 15 surrounded by the annular opening 14 is also referred to as a second magnetic sheet part 15, and the other part is also referred to as a first magnetic sheet part. The first magnetic sheet part and the second magnetic sheet part are integrally formed, and include a connecting part 16 that connects a part of the second magnetic sheet part 15 and a part of the first magnetic sheet part. Yes. The second magnetic sheet portion is disposed apart from the edge of the opening 14 except for the portion where the connecting portion 16 is formed, and is circular as a whole, and is similar to the inner shape of the opening 14. When the transmission coil component is configured using the magnetic sheet and the planar coil, the second magnetic sheet portion is arranged so as to be positioned on the winding axis of the planar coil. The power feeding device and the power receiving device are arranged so that the winding axes of the coils included therein are coincident. Therefore, when a permanent magnet is provided as a magnetic attracting member on the central axis of the coil of the power feeding device, the portion 15 (second magnetic sheet portion 15) surrounded by the annular opening 14 is disposed opposite to the permanent magnet. It can function as a magnetic adsorption member. Even in such a case, since the second magnetic sheet portion 15 is disposed away from the edge of the opening 14, the flow of magnetic flux from the second magnetic sheet portion 15 to the first magnetic sheet portion and the The magnetic saturation of the first magnetic sheet portion due to can be suppressed. The width of the connecting portion 16 is smaller than the dimension of the second magnetic sheet portion 15 viewed in the width direction, and it is necessary that the outer shape of the second magnetic sheet portion 15 is recognizable as a circle, a rectangle, or the like. is there. Furthermore, the magnetic sheet shown in FIG. 5 has a communication portion 17 that allows the opening 14 to communicate with the outer edge side of the first magnetic sheet portion. Although the structure which does not form the communication part 17 may be sufficient, when the communication part 17 is formed, when forming the opening part 14, the removal of the thin strip of this part becomes easy. Depending on the configuration of the adsorption function, the second magnetic sheet portion may not be provided, and it may be a simple circular or rectangular opening, or may not be a complete opening but a recess. is there.

  The laminated magnetic sheets are preferably fixed to the reinforcing member in order to prevent breakage. Specifically, it is preferable to use a magnetic sheet obtained by laminating a soft magnetic alloy ribbon or the like with a resin sheet or the like. A resin sheet may be provided on one of the two main surfaces of the front and back, or may be provided on both. However, it is more preferable to provide resin sheets on both the front and back two main surfaces from the viewpoint of ensuring strength and preventing scattering of fragments at the time of breakage. Further, the ferrite layer and the soft magnetic alloy ribbon layer may be divided into pieces while being fixed to the resin sheet. For example, by providing split grooves, recess rows, through-hole rows, etc. formed at predetermined intervals in two orthogonal directions, and dividing the ferrite layer into pieces along the split grooves etc. in a state where the resin sheet is fixed Flexibility can be imparted to the ferrite layer. Further, eddy current can be suppressed by dividing the soft magnetic alloy ribbon layer into pieces. From this point of view, slits are also effective. In the case of forming such divided grooves and the like, the structure can be different between the ferrite layer and the soft magnetic alloy ribbon. For example, the interval between the individual pieces may be larger in the soft magnetic alloy ribbon layer than the ferrite layer, or only the ferrite layer is regularly divided into individual pieces at a predetermined interval, and the soft magnetic alloy ribbon layer is in accordance with such rules. It may be possible not to divide into individual pieces.

  When arranging the magnetic sheet so as to face the coil, the ferrite layer and the soft magnetic alloy ribbon layer may be arranged as a single unit, or a separate ferrite layer and soft magnetic alloy ribbon layer may be arranged sequentially. May be. Alternatively, a ferrite layer may be attached to a coil, and a soft magnetic alloy ribbon layer may be attached to a substrate or a secondary battery, and these may be brought close to or in close contact with each other.

Example 1
The transmission coil component was configured using a rectangular magnetic sheet shown in FIG. Among the magnetic sheets, a Ni—Zn ferrite sintered body was used for the ferrite layer, and a microcrystalline soft magnetic alloy ribbon was used for the soft magnetic alloy ribbon layer. The Ni-Zn ferrite sintered body uses an MS-NF material (thickness: 100 μm) manufactured by Hitachi Metals, with 10 μm thick PET resin on one side and 10 μm thick on the other side. An adhesive sheet was attached. Further, as a microcrystalline soft magnetic alloy ribbon, Finemet (registered trademark) (FT-3M material, thickness 18 μm) manufactured by Hitachi Metals, Ltd. was used. In the case where the ribbon is formed of a plurality of layers, a double-sided adhesive sheet (thickness 10 μm) was stuck and laminated, and a PET resin having a thickness of 31 μm was stuck to the ribbon exposed on the uppermost surface. The outer dimensions of the magnetic sheet are 40 mm long and 45 mm wide. A plurality of magnetic sheets having different numbers of soft magnetic alloy ribbons were prepared. A transmission coil component on the power receiving side (secondary side) was configured by combining a magnetic sheet and a planar coil. At this time, evaluation was made in two ways: a configuration in which the ferrite layer is disposed on the coil side and a configuration in which the soft magnetic alloy ribbon layer is disposed on the coil side. The planar coil was constructed by winding two parallel wires with a wire diameter of 0.32 mm for 15 turns, and the outer shape of the coil was a 40 × 20 mm rectangle, and the inner shape was a 20 mm × 10 mm rectangle. On the other hand, a planar coil on the power supply side (primary side) is formed by winding a litz wire with a wire diameter of 1 mm for 20 turns (10 turns, 2 stages), the outer shape of the coil is a circle with a diameter of 40 mm, and the inner shape is a diameter of 20 mm The round shape. Ferrite was used for the primary side magnetic sheet. The transmission coil part is configured by aligning the center of the magnetic sheet and the planar coil, and the transmission coil part on the power feeding side and the transmission coil part on the power receiving side are arranged in the same manner as in FIG. 1, and the inductance Ls and Q value are measured at 120 kHz. did. The results are shown in Table 1.

  When the inductance Ls obtained in the configurations of Nos. 1, 3, 5 and 7 in which the ferrite layer is disposed on the coil side and the soft magnetic alloy ribbon layer is disposed on the opposite side is obtained with a magnetic sheet using only ferrite as a magnetic body. 215 μm (total thickness of magnetic material 195 μm), 275 μm (total thickness of magnetic material 255 μm), 315 (total thickness of magnetic material 295 μm), 375 μm (total thickness of magnetic material 355 μm), and the total thickness of the magnetic sheet shown in Table 1 I found it smaller. Therefore, it can be seen that the transmission coil components can be downsized in the examples of Nos. 1, 3, 5 and 7 having the configuration of the present invention. Further, in any case where the number of soft magnetic alloy ribbon layers was 1 to 4, no significant difference was found in the inductance Ls even when the arrangement of the magnetic sheet on the coil side was changed. However, a large difference was seen in the Q value by changing the positional relationship between the magnetic sheet and the coil. That is, by arranging the ferrite layer on the coil side, the Q value is higher than in the case where the soft magnetic alloy ribbon layer is arranged on the coil side, and the manner of arrangement of the magnetic sheet is important. all right. In particular, it can be seen that the effect is remarkable in the configurations of Nos. 3, 5, and 7 having two or more soft magnetic alloy ribbons.

DESCRIPTION OF SYMBOLS 1, 6: Magnetic sheet 2, 7: Planar coil 3, 9: Board | substrate 4: Secondary battery 5: Power receiving apparatus 8: Magnetic adsorption member 10: AC power supply 11: Circuit part 12: Power supply apparatus 13: Magnetic sheet 14: Opening 15: a portion surrounded by an annular opening 43 (second magnetic sheet portion)
16: Connection part 17: Communication part

Claims (5)

A coil, and a magnetic sheet disposed to face the coil,
The magnetic sheet has a ferrite layer and a soft magnetic alloy ribbon layer having two or more soft magnetic alloy ribbons having a saturation magnetic flux density larger than the ferrite layer ,
The ferrite layer is a Ni-Zn ferrite sintered body having a resistivity of 10 ⁵ Ω · m or more,
A transmission coil component for a non-contact charging device arranged such that the ferrite layer is on the coil side. The transmission coil component according to claim 1, wherein the soft magnetic alloy ribbon of the soft magnetic alloy ribbon layer is a nanocrystalline soft magnetic alloy ribbon having a saturation magnetic flux density of 1.2 T or more .   A power receiving device for a non-contact charging device, comprising the transmission coil component according to claim 1.   A power feeding device for a non-contact charging device, comprising the transmission coil component according to claim 1. A non-contact charging device having a power feeding device and a power receiving device that are used facing each other,
A non-contact charging device comprising the transmission coil component according to claim 1 or 2 in at least one of the power feeding device and the power receiving device.

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