JP2014187724A - Secondary power-receiving apparatus and charging stand and secondary power-receiving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for charging, while suppressing loss, even if mounted on a charging stand using a positioning magnet, without thickening a magnetic sheet.SOLUTION: A secondary power-receiving apparatus mounted on a charging stand 100 including a positioning magnet, and receiving power from a transmission coil 101 built in the charging stand 100 includes a reception coil 11 which can be coupled electromagnetically with the transmission coil 101 built in the charging stand 100, a rectification control circuit for outputting the power received by the reception coil 11 while rectifying, and a magnetic sheet 17 arranged on the back of the reception coil 11. Hollow section of the reception coil 11 and the positioning coil 102 can be aligned by magnetic force. Since the magnetic sheet can be attracted to the positioning magnet and positioned, arrangement of extra magnet, magnetic material, or the like, is not required.

Description

  The present invention electromagnetically couples a power receiving coil of a secondary power receiving device mounted on a charging base and a power transmitting coil of the charging base, and carries power by magnetic induction from the power transmitting coil to the power receiving coil to charge a built-in battery. The present invention relates to a possible secondary side power receiving device, and a combination of a charging base and a secondary side power receiving device that transmits power to the secondary side power receiving device.

  Many battery-driven devices typified by mobile devices such as mobile phones and portable music players are driven by a rechargeable battery for convenience of carrying. Such a battery-driven device stores a battery in a unit cell state or a battery pack state. The battery-driven device is charged by connecting a contact to a charger in a state where the battery is accommodated. On the other hand, a charging stand that charges the battery by transporting power to the receiving coil from the power transmission coil built in the charging stand using the action of electromagnetic induction without connecting the contacts in this way has been developed. (See Patent Document 1).

  As shown in FIG. 11, the charging base shown in Patent Literature 1 includes a power transmission coil 911 that is excited by an AC power supply in a charging base 910, and a power receiving coil 921 that is electromagnetically coupled to the power transmission coil 911 is connected to a battery pack 930. The secondary battery cell 931 of the battery pack 930 is charged with electric power induced in the power receiving coil 921. The battery pack 930 has a built-in charging circuit that rectifies the alternating current induced by the power receiving coil 921 and supplies it to the secondary battery cell 931 for charging. The battery pack 930 is built in the battery driving device 920 for supplying power. The battery pack 930 and the battery driving device 920 have a recess 922 for positioning with the charging base 910. Further, on the charging base 910 side, a convex portion 912 for positioning is provided at a position facing the concave portion 922. According to this structure, the battery-driven device 920 is placed on the charging base 910, the concave portion 922 is inserted into the convex portion 912, and the secondary contact is made in a non-contact state without connecting a physical contact for electrical connection. The battery cell 931 can be charged. However, since the battery driving device 920 and the battery pack 930 require a concave portion and a convex portion, the structure is not good in appearance. In addition, when the convex portion is not completely inserted into the concave portion, there is a problem that the battery-driven device is lifted from the charging stand, the distance between the power receiving coil and the power transmitting coil is increased, and the electromagnetic coupling efficiency is deteriorated.

  In such contactless charging, it is important to bring the power transmission coil of the charging stand close to the power receiving coil of the battery-driven device placed on the charging stand, in other words, positioning between these coils. In order to realize such positioning, a plurality of methods have been proposed. For example, a method in which the power transmission coil is moved in the XY direction inside the charging base, a plurality of power transmission coils are laid flat on the charging base, In order to match the power receiving coil side with the power transmission coil, on the contrary, the method of selecting the power transmission coil close to the power receiving coil in the method or the method of adjusting the position of such power transmission coil according to the placement position of the power receiving coil, For example, a method has been developed in which a positioning magnet is provided on a charging stand, and positioning is performed by attracting the battery plate with a metal plate, a magnetic sheet, or a magnet on the battery drive device side.

  However, in the case of performing contactless charging with the above-described positioning method using the positioning magnet for the battery-powered device in which such a magnetic sheet is disposed, the positioning disposed on the charging stand 100 as shown in FIG. Since the magnet 102 and the magnetic shield 37 are overlapped, the magnetic sheet 37 in this overlapping portion is saturated and the magnetic permeability is lowered, and the magnetic flux from the power transmission coil, the power receiving coil, and the positioning magnet 102 passes through the magnetic sheet 37, so that the magnetic The function of shielding the outer can of the secondary battery cell 12 disposed on the back surface of the body sheet 37 is impaired. Furthermore, a part of the power receiving coil 31 overlaps with a portion through which the magnetic flux of the magnetic shield 37 passes, and eddy current loss occurs in the outer can of the secondary battery cell 12 disposed on the back surface of the magnetic shield 37. There is a problem that the inductance L value decreases, the contactless charging does not operate normally, and the loss increases.

  In order to solve such problems, the shielding effect of the magnetic sheet is enhanced, and even if the magnetic sheet is partially overlapped with the positioning magnet of the charging stand, sufficient shielding ability can be exhibited. Can be considered. However, in order to enhance the shielding effect of the magnetic sheet, it is necessary to increase the thickness of the magnetic sheet. In this case, the thickness of the battery pack increases, which makes it impossible to reduce the size of the battery pack. It was.

JP 2008-141940 A

  The present invention has been made to solve such conventional problems. The main object of the present invention is to provide a secondary side power receiving device and a power receiving device capable of suppressing loss and charging even when placed on a charging stand using a positioning magnet without increasing the thickness of the magnetic sheet. It is to provide a power stand and a secondary power receiving device.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, the secondary power receiving device according to the first aspect of the present invention is placed on a charging stand including a positioning magnet and can receive power from a power transmission coil built in the charging stand. A secondary power receiving device, which is a hollow power receiving coil 11 that can be electromagnetically coupled to the power transmitting coil 101 built in the charging stand 100, and a rectification control circuit that rectifies and outputs the power received by the power receiving coil 11. The magnetic material sheet 17 disposed on the back surface of the power receiving coil 11 can be configured so that the hollow portion of the power receiving coil 11 and the positioning magnet 102 can be aligned by magnetic force. Thereby, since a magnetic material sheet is attracted | sucked and positioned by the positioning magnet, it is not necessary to arrange | position a magnet, a magnetic body, etc. separately.

  Further, according to the secondary power receiving device according to the second side surface, the inner diameter of the hollow portion of the power receiving coil 11 is substantially equal to or larger than the outer diameter DM of the positioning magnet 102. As a result, when the battery pack is placed on the charging base during charging, the positioning magnet and the power receiving coil are avoided from overlapping with each other, and the magnetic material sheet built in the battery driving device side by the positioning magnet and the power receiving coil 11. This can reduce the effect of lowering the characteristics. As a result, even when the contactless charging method of the battery pack is shared with the method of positioning using the positioning magnet, the thickness of the magnetic material sheet can be kept thin, and the battery pack can be downsized.

  Furthermore, according to the secondary power receiving device according to the third aspect, the power receiving coil 11 has a rectangular outer shape. Thus, the rectangular power receiving coil can be further separated from the positioning magnet of the charging stand even with the same inner diameter as the circular power receiving coil. Furthermore, the magnetic material sheet can be thinned by changing the shape of the coil.

  Furthermore, according to the secondary side power receiving apparatus which concerns on a 4th side surface, the hollow part of the said receiving coil 11 is air core shape. As a result, the magnetic sheet can be exposed in the hollow portion of the power receiving coil, and the magnetic force of the positioning magnet can be directly received to increase the attractive force.

  Furthermore, according to the secondary power receiving device according to the fifth aspect, a thin wire can be used for the wire constituting the power receiving coil 11. Thereby, the wire diameter of the wire which can obtain required charging efficiency and resistance value can be made thinner than before. As a result, since the distance between the magnetic sheet and the positioning magnet is reduced, the magnetic force of the positioning magnet can be directly received to increase the attractive force.

  Furthermore, according to the secondary power receiving device according to the sixth aspect, the magnetic sheet 17 is made of a soft magnetic ferrite that generates an attractive force by the magnetic force of the positioning magnet 102. Thereby, a magnetic material sheet can receive the magnetic force of a positioning magnet to the maximum by making it a ferrite of a soft magnetic material, and can increase an attractive force.

  Furthermore, according to the secondary power receiving device according to the seventh aspect, the power receiving device has a series capacitor 13 connected in series with the power receiving coil 11 to form a resonance circuit, and the capacitance of the series capacitor 13 is The power receiving coil 11 is adjusted to a value that provides a predetermined resonance frequency. As a result, it is possible to increase the capacitance of the series capacitor and adjust the resonance frequency to a desirable resonance frequency by increasing the inner diameter of the power receiving coil as compared with the prior art and reducing the number of turns and the inductance, thereby efficiently transmitting power.

  Furthermore, according to the secondary side power receiving apparatus which concerns on an 8th side surface, the secondary battery cell 12 installed in the back surface of the magnetic material sheet 17 can be charged with the output from the said rectification | straightening control circuit. Thereby, it can be set as the battery pack which made the secondary side power receiving apparatus and the secondary battery cell one set. Furthermore, the secondary battery cell can be prevented from being heated by the magnetic sheet.

  Furthermore, according to the secondary side power receiving device according to the ninth aspect, the battery pack further includes a rechargeable secondary battery cell 12, and the secondary side power receiving device is connected to a battery driving device, While supplying electric power for driving the driving device from the secondary battery cell 12, the battery pack 10 is mounted on the charging stand 100 and can be charged by receiving electric power from a power transmission coil built in the charging stand 100.

  Furthermore, according to the charging stand and the secondary power receiving device according to the tenth aspect, there is a charging stand 100 and a secondary power receiving device that is placed on the charging stand 100 and can receive power, The base 100 includes a positioning magnet 102 and a power transmission coil 101, and the secondary power receiving device receives the hollow power reception coil 11 that can be electromagnetically coupled to the power transmission coil 101 and the power reception coil 11. A rectification control circuit that rectifies and outputs electric power, and a magnetic sheet 17 disposed on a back surface of the power receiving coil 11, and the power receiving coil 11 supplies the secondary power receiving device to the charging stand 100. The inner diameter of the hollow portion of the power receiving coil 11 is made substantially equal to or larger than the outer diameter DM of the positioning magnet 102 so that the positioning magnet can be disposed in the hollow portion of the power receiving coil 11 in the mounted state. It made. Thereby, when the battery pack is placed on the charging stand during charging, it is possible to avoid the overlapping of the positioning magnet and the power receiving coil, and to mitigate the influence of the magnetic properties of the magnetic material sheet and the power receiving coil being lowered by the positioning magnet.

It is a perspective view which shows the state in which the battery pack which concerns on the Example of this invention was installed in the charging stand. It is a vertical sectional view concerning the charging stand and battery pack shown in FIG. It is a perspective view which shows the charging stand which displayed the mark which concerns on a modification. It is a circuit diagram concerning the circuit of a battery pack. FIG. 5A is a plan view illustrating a circular power receiving coil, and FIG. 5B is a plan view illustrating a square power receiving coil according to the first embodiment. It is a perspective view which shows the state which mounted the battery drive apparatus which connected the battery pack of FIG. 1 on the charging stand. It is a perspective view which shows the state which mounted the battery drive apparatus incorporating the battery pack which concerns on a modification on the charging stand. It is the perspective view which mounted the battery pack of the Example on the charging stand which made the conventional receiving coil movable to XY direction. It is the vertical sectional view which mounted the battery pack made experimentally by the present inventors on the charging stand. It is the vertical sectional view which mounted the battery pack provided with the circular receiving coil concerning the example of the present invention on the charging stand. It is vertical sectional drawing which shows the state which set the battery drive apparatus to the charging stand by the conventional non-contact charge. It is a perspective view which shows the state which connects the secondary side power receiving apparatus which concerns on the other Example of this invention to a battery drive apparatus, and is installed in a charging stand.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a secondary side power receiving device, a charging stand and a secondary side power receiving device for embodying the technical idea of the present invention, and the present invention is a secondary side power receiving device. The equipment and charging stand and secondary power receiving equipment are not specified as follows. Further, in the present specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the embodiments are indicated in the “claims” and “means for solving problems” sections. It is appended to the members shown. However, the members shown in the claims are not limited to the members in the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

  The secondary side power receiving device according to the embodiment of the present invention is a secondary side power receiving device that can be electromagnetically coupled to the contactless primary side charger. This secondary-side power receiving device includes a power receiving coil and a rectification control circuit, and can be power that can supply power to an external load device. As such a secondary-side power receiving device, for example, a battery pack incorporating a secondary battery cell can be used. The secondary-side power receiving device that is a battery pack supplies the power received from the charging stand to the secondary battery cell and charges it. Further, the secondary power receiving device is not limited to the one in which the battery pack is integrated, and may be an adapter that directly supplies power to the load device, for example. In the example of the secondary-side power receiving device shown in FIG. 12, a charging adapter 10 ′ including a power receiving coil that can be electromagnetically coupled to a power transmitting coil built in the charging stand 100 ′ is used. By using the secondary power receiving device as the charging adapter 10 ′, the power transmitted from the charging stand 100 ′ without contact is supplied to the mobile phone that is the battery-driven device 50 ′ and is built in the mobile phone. A secondary battery can be charged and a mobile phone can be driven. With this configuration, even if the battery-powered device 50 ′ does not support contactless charging, charging can be performed by interposing a charging adapter that is a secondary power receiving device, and existing devices can be contactlessly charged. It can be.

  The secondary power receiving device includes a power receiving coil that receives magnetic flux from the power transmitting coil, and further includes a magnetic sheet on the back of the power receiving coil. On the back of the magnetic sheet, a rectification control circuit including a sheet metal, a printed board, an electronic circuit, and the like that rectifies the power received by the power receiving coil is disposed. Thereby, the secondary side power receiving apparatus can use the induced electromotive force as the secondary power, and can further prevent the rectification control circuit from being heated by the magnetic flux by the magnetic sheet.

Hereinafter, as an example of the secondary-side power receiving device, an example of a battery pack that is placed on a charging stand and can be charged without contact or wirelessly will be described with reference to FIGS. In these drawings, FIG. 1 is a perspective view of the battery pack placed on the charging stand according to the embodiment, FIG. 2 is a vertical sectional view of the charging stand and the battery pack shown in FIG. 1, and FIG. FIG. 4 is a circuit diagram relating to a battery pack charging circuit, FIG. 5A is a plan view of a circular power receiving coil, and FIG. 5B is a rectangular power receiving coil. FIG. 6 is a perspective view showing a state in which the battery driving device to which the battery pack of FIG. 1 is connected is placed on the charging stand, and FIG. 7 is a drawing showing the battery driving device incorporating the battery pack according to the modification. The perspective view which shows the mounted state is shown, respectively. Furthermore, an example of a battery pack prototyped by the present inventors is shown in FIGS. 9 to 10 and will be described in comparison.
(Charging stand 100)

  FIG. 1 shows a battery pack 10 as a secondary power receiving device placed on a charging stand 100. The charging stand 100 is a contactless charging stand that performs charging without contact. The charging stand 100 is provided with a power input connector 103 as an input terminal for power. Further, power is supplied to the power input connector 103 by converting commercial power into DC power using an AC / DC adapter (not shown) and connecting the DC output connector 104 for supply.

  Further, the charging stand 100 is constituted by a rectangular charging stand case 105 whose upper surface of the outer shape is a substantially flat mounting surface. The charging stand case 105 can be made of, for example, a resin that does not disturb the magnetic flux. Although not shown, the charging stand 100 has a high-frequency oscillation circuit that uses the power supplied from the power input connector 103 as high-frequency power.

This high frequency power is supplied as high frequency oscillated power to the power transmission coil 101 shown in the cross-sectional view of FIG. The high-frequency oscillated power is energized in the power transmission coil 101 to generate magnetic flux, and an induced electromotive force can be generated in the power receiving coil 11 of the battery pack 10 disposed in proximity.
(Positioning magnet 102)

  The power transmission coil is a planar coil in which a hollow portion is formed in the central portion as shown in the plan view of FIG. Further, the charging stand 100 shown in the cross-sectional view of FIG. 2 has a positioning magnet 102 disposed in a hollow portion of the power transmission coil 101. The positioning magnet 102 has a cylindrical shape with an outer diameter DM that is approximately the same as or slightly smaller than the size of the hollow portion of the power transmission coil 101. For example, in the positioning magnet 102 of this embodiment, the circular surface on the battery pack 10 side facing the upper surface of the charging base case 105 is an N pole or an S pole. As will be described later, in FIG. 2, a power receiving coil 11 having a rectangular shape is used as the outer shape of the power receiving coil as shown in FIG.

  Further, the positioning magnet 102 positions the power receiving coil 11 of the battery pack 10 by using an attractive force due to magnetic force. Thereby, the power reception coil 11 in the battery pack 10 can be brought close to the transmission coil 101 of the charging stand 100, and the magnetic flux generated from the transmission coil 101 can be efficiently converted into an induced electromotive force.

  The charging stand 100 using the positioning magnet 102 indicates the mounting position so that the battery pack or the battery driving device can be easily placed at a predetermined position on the upper surface of the charging stand case 105 as shown in FIG. A mark 106 is preferably provided. The user places the battery pack or the battery-driven device in a rough position according to the mark 106 on the charging stand, whereby the battery pack or the battery-driven device can be positioned and electromagnetically coupled by the magnetic force of the positioning magnet 102.

Furthermore, the positioning magnet 102 used here preferably has a strong magnetic force. For example, it is preferable that the battery pack or the battery driving device placed on the mounting surface of the charging stand 100 can correct the position by magnetic force. In other words, the weight of the battery pack or the battery driving device is set to a magnetic force that can move on the mounting surface of the charging stand 100, and preferably a neodymium positioning magnet 102.
(Battery pack)

  The power receiving coil 11 is connected to the series capacitor 13 shown in FIG. 4 in series, and can be tuned to the power transmitting coil 101 to generate an induced electromotive force having a resonance frequency near the maximum. This induced electromotive force can output and supply power to the secondary battery cell 12 via the synchronous rectification control circuit 14 as a rectification control circuit having a plurality of control circuits of the battery pack 10.

  Further, although not shown, the synchronous rectification control circuit 14 converts high-frequency power from the power receiving coil 11 and the series capacitor 13 into DC power by a rectifier circuit and a smoothing circuit. The secondary battery cell 12 can charge the converted DC power by a charging circuit (not shown) in the synchronous rectification control circuit 14.

  Furthermore, the synchronous rectification control circuit 14 monitors the charging voltage, charging / discharging current, and battery temperature of the secondary battery cell 12. When the secondary battery cell 12 exceeds a predetermined threshold by this monitoring information, the charging of the secondary battery cell 12 can be stopped and the safety of the battery pack 10 can be improved.

The battery pack 10 in the embodiment shown in FIG. 2 has a magnetic sheet 17 that insulates the power receiving coil 11 from the secondary battery cell 12, and the power receiving coil 11 has a hollow space 16 in which the inner shape is hollow. Have. In the battery pack in this embodiment, the exterior can be made of a resin such as plastic, or only the surface of the power receiving coil side where it joins the charging base can be a plastic film.
(Secondary battery cell 12)

  The secondary battery cell 12 incorporated in the battery pack 10 is a rectangular parallelepiped that is thinner than the width, and can be formed of an outer can that is integrally formed with each surface to form a metal case. For example, the metal case can be made of aluminum or the like, can be protected from exogenous impacts, and can have an excellent effect in terms of weight reduction and heat dissipation. Such a secondary battery cell 12 is affected by electromagnetic induction as a component.

  The secondary battery cell in this example uses a lithium ion secondary battery or a lithium polymer battery with a large volumetric energy density, so that the whole is light, thin, small and convenient, and further has an output power capacity. Since it can be enlarged, it has a feature that can be used for battery-powered devices. However, the present invention is not limited to this, and the secondary battery cell can be any rechargeable secondary battery such as a nickel metal hydride battery or a nickel cadmium battery.

  FIG. 9 to FIG. 10 show battery packs 30 and 40 made by the present inventors as prototypes. The battery packs 30 and 40 can position the power receiving coils 31 and 41 using the attractive force of the positioning magnet 102 provided on the charging stand 100. First, in the battery pack 30 of FIG. 9, the magnetic sheet 37 is disposed between the secondary battery cell 12 and the power receiving coil 31, and the hollow portion of the power receiving coil 31 is used as an air-core-shaped gap 36. As a result, the magnetic sheet 37 is attracted by the positioning magnet 102 of the charging stand 100. Further, the central axis of the power receiving coil 31 can be made to coincide with the central axes of the power transmitting coil 101 and the power receiving coil 31 by the attractive force of the positioning magnet 102. Thereby, the power transmission coil 101 and the power reception coil 31 can be electromagnetically coupled.

  However, as shown in FIG. 9, a part of the power receiving coil 31 is overlapped with the positioning magnet 102 arranged on the charging stand 100. For this reason, the positioning magnet 102 and the magnetic sheet 37 are integrated via the power receiving coil 31, the magnetic shield 37 is saturated and the magnetic permeability is lowered, and the magnetic flux from the power transmitting coil, the power receiving coil, and the positioning magnet 102 is magnetic. In order to pass through the body sheet 37, that is, the characteristics of the magnetic shield 37 are deteriorated, and the function of shielding the outer can of the secondary battery cell 12 is impaired. Loss. That is, the characteristics of the power receiving coil 31 are deteriorated. In this figure, the outer diameter D and inner diameter d ′ of the power receiving coil 31 and the outer diameter DM of the positioning magnet 102 are used. As shown in this figure, the receiving coil 31 and the magnetic sheet 37 have an overlapping portion OL that overlaps the positioning magnet 102. In order to solve this, it is necessary to increase the thickness of the magnetic sheet 37 to the thickness t3 of the magnetic sheet. As a result, the thickness of the battery pack 30 is increased with respect to the tendency to reduce the thickness of battery-driven devices and the like, and there is a concern that the battery pack 30 may go backward.

  Further, in another prototype battery pack 40, a magnetic sheet 47 is arranged between the secondary battery cell 12 and the power receiving coil 41 as shown in FIG. In this figure, the outer diameter D and inner diameter d of the power receiving coil 41 and the outer diameter DM of the positioning magnet 102 are used. Further, the power receiving coil 41 is provided with an air-core-shaped gap 46 in which the inner diameter d of the power receiving coil 41 is substantially equal to or larger than the outer diameter of the positioning magnet 102. For this reason, the magnetic material sheet 47 is widened in the magnetized state by the positioning magnet 102. As a result, the battery pack 40 has a magnetic material sheet thickness t2 in which the magnetic sheet 47 is thinned because the attractive force to the positioning magnet 102 is increased by widening the range of the magnetized state. With this configuration, a sufficient shielding effect can be exhibited without improving the characteristics of the magnetic sheet, so that it can be configured at low cost without using an expensive magnetic sheet, and the magnetic sheet is made thinner. be able to. According to the prototype of the present inventors, the power receiving coil 31 of the battery pack 30 shown in FIG. 9 uses a circular coil having an inner diameter d ′ = 10 mmφ and an outer diameter D = 30 mmφ. On the other hand, since the positioning magnet 102 of the charging stand 100 has an outer diameter DM of 15 mm, an overlapping portion OL that is an overlapping portion of about 5 mm is generated. In order to suppress this, the thickness t3 of the magnetic material sheet 37 is required to be about 0.9 mm. On the other hand, in the battery pack 40 shown in FIG. 10, the outer diameter D of the circular power receiving coil 41 is 30 mmφ, and the inner diameter d is 20 mmφ. Thereby, the receiving coil 41 and the positioning magnet 102 can eliminate the overlapping portion OL which is an overlapping portion, and problems such as a decrease in the magnetic permeability of the magnetic material sheet 47 can be eliminated. For this reason, it has become possible to reduce the thickness t2 of the magnetic material sheet 47 to 0.6 mm. In this way, by increasing the gap 46 that is the inner diameter of the air core portion of the power receiving coil, the magnetic material sheet 47 can be thinned, and the battery pack can be further thinned.

  Further, as shown in FIG. 5A, the power receiving coil 41 is formed into a planar circular coil, and has an outer diameter D and an inner diameter d of the power receiving coil 41. In the power receiving coil 41, the inner diameter d is substantially equal to or larger than the positioning magnet 102 of the charging stand 100. In the comparison between FIG. 9 and FIG. 10 described above, the outer diameter is the same and the inner diameter is larger in FIG. The loss that occurs is improved. On the other hand, the number of turns of the coil decreases, and the inductance decreases.

  In FIG. 2, a receiving coil 11 having a rectangular shape is used as the outer shape of the receiving coil as shown in FIG. Therefore, in this embodiment, in order to efficiently perform electromagnetic coupling, it is preferable that the outer shape of the power receiving coil as shown in FIG. The power receiving coil 11 has a length L on one side of the outer shape equal to the outer shape D of the power receiving coil 41, and a length l on one side of the inner shape equal to the inner diameter d of the power receiving coil 41. The length l of one side of the inner shape of the power receiving coil 11 is about 1.27 times the area of the inner diameter d of the power receiving coil 41. Accordingly, the power receiving coil 11 shown in FIG. 2 can form a further expanded air core portion, is separated from the positioning magnet 102 of the charging base 100, and can reduce the influence of the magnetic field. Further, the power receiving coil 11 can reduce the inductance reduction of the coil as the wire length increases as compared with the circular shape having the inner diameter d.

  Furthermore, the wire used for the power receiving coil 11 is a formal wire or enameled wire in which an insulating metal wire is used and the wire skin is insulated with an insulating film. In the power transmission coil 101, a high-frequency current flows from a high-frequency power source, and a magnetic flux associated therewith is generated. The power receiving coil 11 electromagnetically induces the magnetic flux to generate an induced electromotive force. As this high frequency, for example, 20 kHz to 1 MHz is used. The receiving coil 41 that receives high-frequency power can be more efficiently electromagnetically coupled to generate an induced electromotive force as the area receiving the magnetic flux is larger. As a result, the rectangular power receiving coil 11 can widen the area for receiving the magnetic flux approximately 1.27 times that of the circular power receiving coil 41, so that a decrease in inductance can be suppressed, and the induced electromotive force can be reduced. It can be generated efficiently.

Here, in FIGS. 2 and 5B, for example, the length l of one side of the inner shape of the rectangular power receiving coil 11 is 20 mm, and the length L of one side of the outer shape is 30 mm. As a result, the power receiving coil 11 and the positioning magnet 102 can be further separated from each other. As a result, the thickness t1 of the magnetic material sheet 17 can be reduced to 0.52 mm. In the example of FIG. 5B, the entire outer shape is a square shape, and the octagonal shape is chamfered at the corner, but the present invention is not limited to this example. For example, other rectangular shapes such as a rectangular shape and a hexagonal shape can be used. In addition, the square coil has an advantage that the inductance can be increased because the coil wire is longer than the circular power receiving coil 41. Thus, the thickness of the magnetic material sheet can be adjusted by adjusting the inner diameter or the inner shape of the power receiving coil. In addition, in this specification, the thing with the external shape chamfered as shown in FIG.5 (b) is also included in a "square-shaped coil."
(Void 16)

  Further, the power receiving coil 11 is provided with a magnetic material sheet 17 between the secondary battery cells 12, and the hollow portion of the coil has an air core shape, which is used as a gap 16. Further, the magnetic sheet 17 of the power receiving coil 11 can receive the magnetic force of the positioning magnet 102 of the charging stand 100 directly in the absence of an obstacle by forming the space of the gap 16. As a result, the battery pack 11 placed on the charging stand 100 directly attracts the magnetic sheet 17 with the magnetic force of the positioning magnet 102 and aligns the central axis of the power receiving coil 11 with the central axis of the power transmitting coil 101. be able to. The adjacent power transmission coil 101 and power reception coil 11 can be efficiently electromagnetically coupled and can generate an induced electromotive force.

Furthermore, the air gap 16 that is the air core of the power receiving coil 11 can be expanded more than the air gap 46 of the circular power receiving coil 41. For this reason, the positioning magnet 102 can further separate the power receiving coil 11, and the magnetic permeability of the magnetic sheet 17 due to the overlapping of the coil and the positioning magnet 102 is prevented from being lowered, and the influence on the outer can of the secondary battery cell 2 is prevented. Can be reduced.
(Magnetic sheet 17)

  The magnetic sheet used here is composed of a member having a low magnetic resistance, for example, a soft magnetic ferrite having a high magnetic permeability. Further, as the magnetic sheet, a sheet of ferrite can be used. In addition, a sheet in which a soft magnetic material powder or flake is applied and mixed in a resin can be used. Furthermore, it is preferable that the magnetic sheet suppresses the magnetic loss coefficient while increasing the magnetic permeability. Thus, the magnetic sheet can effectively prevent the outer can of the secondary battery pack 12 from being heated by eddy current loss due to electromagnetic induction.

Furthermore, the battery pack 10 having a thin magnetic sheet can make the battery pack itself thinner. The magnetic sheet 17 in which the soft magnetic ferrite is formed into a sheet shape can efficiently use the magnetic force of the positioning magnet 102 of the charging stand 100 as an attractive force. Furthermore, as described above, in the inner diameter d having the same outer diameter and the larger inner diameter, the resistance value of the receiving coil with the inner diameter d is lower than the inner diameter d ′, and the resistance loss of the receiving coil portion is reduced, and the charging efficiency is reduced. Is advantageous over the inner diameter d ′, but if the required charging efficiency and resistance equivalent to the inner diameter d ′ can be obtained, the wire diameter of the power receiving coil can be reduced. By reducing the coil wire diameter, the distance between the magnetic material sheet 17 and the positioning magnet 102 can be shortened, and the magnetic force of the positioning magnet 102 of the charging stand 100 can be efficiently used as the attractive force. For example, it is preferable that the battery pack or the battery driving device placed on the mounting surface of the charging stand 100 can correct the position by magnetic force. In other words, the magnetic sheet can be a ferrite of a soft magnetic material that can convert the weight of the battery pack or the battery-driven device into a magnetic force that can move the weight of the battery pack or the battery driving device on the mounting surface of the charging stand 100.
(Series capacitor 13)

  On the other hand, the battery pack capable of contactless charging needs to match the inductance L value and the capacitance C value of the power receiving coil and the series capacitor so as to be tuned to the resonance frequency from the transmitting coil of the charging stand. When the inner diameter of the power receiving coil is increased, in other words, when the air core diameter is increased, the number of turns of the power receiving coil is reduced and the inductance L value is relatively lowered. For example, when the inner diameter of the circular power receiving coil is changed from 15.5 mmφ to 17.5 mmφ with the same coil wire length, the inductance L value decreases from 33 μH to 20 μH. For this reason, the LC series resonance frequency can be maintained by increasing the capacitance C value of the series capacitor 13 connected in series with the power receiving coil as shown in FIG. Here, the capacitance C value of the series capacitor is changed from 60 nF to 100 nF. Thereby, the resonance frequency of the battery pack can be tuned to the resonance frequency on the power transmission coil side. As shown in FIG. 2, the magnetic sheet 17 needs to be arranged in the thickness direction of the battery pack in order to cover the outer can of the secondary battery cell 12. On the other hand, the arrangement position of the series capacitor is not limited to this, and can be arranged in the space in the battery pack. Therefore, the increase in the capacitance C value of the capacitor 13 has almost no effect on the thinning of the battery pack. Is obtained.

  The battery pack 10 according to the embodiment can be used as a detachable battery pack as a power source of the battery driving device 50 such as a mobile phone or a portable music player. FIG. 6 is a perspective view illustrating a state where the battery driving device 50 connected to the battery pack 10 of the embodiment is placed on the charging stand 100. The battery pack 10 attached to the battery drive device 50 can be contactlessly charged by placing the battery drive device 50 on the charging stand 100. The battery drive device 50 can be positioned by the magnetic force of the positioning magnet 102 by placing the battery drive device 50 at a rough position on the mark 106 indicating the placement position of the charging stand 100, for example. Can be electromagnetically coupled. Thereby, the user can easily place the battery-powered device 50 on the charging stand 100 and perform charging. Furthermore, since the battery pack 10 can be contactlessly charged alone, it can be prepared as a spare battery pack 10.

  Furthermore, FIG. 7 is a perspective view showing a state in which a battery driving device incorporating a battery pack according to a modification is placed on a charging stand. The battery drive device 60 in which the battery cannot be attached or detached can be charged by placing the battery pack 10 in the battery pack 10 and placing it on the contactless charging stand 100. The battery-powered battery-powered device 60 is a battery built in the battery-powered device 60 by the magnetic force of the positioning magnet 102 by, for example, being placed at a rough position on the mark 106 indicating the mounting position of the charging stand 100. The pack 10 can be positioned and electromagnetically coupled. Thereby, the user can easily place the battery-powered device 60 on the charging stand 100 and perform charging.

  Furthermore, the battery pack 10 according to the present invention can be contactlessly charged by a conventional method by using such a magnetic sheet 17. As shown in FIG. 2 described above, the magnetic material sheet 17 can be attracted by the magnetic force of the positioning magnet 102 of the charging stand 100. For this reason, this battery pack 10 can be positioned on the charging stand using another positioning magnet.

  On the other hand, as shown in FIG. 8, the battery-driven devices 50 and 60 and the battery pack 10 can be charged even by using a charging base 200 that allows the power transmission coil 201 to move in the XY directions. In this way, by making the battery pack compatible with a plurality of charging standards, the user can continue to use the same battery pack or battery-driven device even if the charging base is replaced with another standard. . In addition, when charging on the go or the like, the number of types of charging bases that can be used is increased, and an advantage of more convenient use can be obtained.

  The secondary-side power receiving device and charging base and the secondary-side power receiving device according to the present invention can be suitably used as a battery pack and a charging base that can charge battery-operated devices such as mobile phones and portable music players in a contactless manner. .

DESCRIPTION OF SYMBOLS 10, 30, 40 ... Battery pack 10 '... Charge adapter 11, 31, 41 ... Receiving coil 12 ... Secondary battery cell 13 ... Series capacitor 14 ... Synchronous rectification control circuit 16, 36, 46 ... Gap 17, 37, 47 ... Magnetic material sheet 50, 50 ', 60 ... Battery drive device 100, 100', 200 ... Charging stand 101, 201 ... Power transmission coil 102 ... Positioning magnet 103 ... Power input connector 104 ... DC output connector 105 ... Charging stand case 106 ... mark 910 ... charging base 911 ... power transmission coil 912 ... convex part 920 ... battery drive device 921 ... power reception coil 922 ... concave part 930 ... battery pack 931 ... secondary battery cell D ... outer diameter d (of power reception coil) ... (of power reception coil 41) ) Inner diameter d '... Inner diameter L (of receiving coil 31) ... Length of one side of outer shape (of receiving coil 11) ... Length of one side of inner shape (of receiving coil 11) DM ... outer diameter OL (of positioning magnet 102) ... overlapping portions t1, t2, t3 ... thickness of magnetic material sheet

Claims (10)

A secondary-side power receiving device that is mounted on a charging stand having a positioning magnet and can receive power from a power transmission coil built in the charging stand,
A hollow power receiving coil (11) electromagnetically coupled with a power transmitting coil (101) built in the charging stand (100);
A rectification control circuit that rectifies and outputs the power received by the power receiving coil (11);
A magnetic sheet (17) disposed on the back surface of the power receiving coil (11);
With
A secondary-side power receiving device, characterized in that the hollow portion of the power receiving coil (11) and the positioning magnet (102) can be aligned by magnetic force. The secondary power receiving device according to claim 1,
A secondary-side power receiving device, wherein an inner diameter of a hollow portion of the power receiving coil (11) is substantially equal to or larger than an outer diameter (DM) of a positioning magnet (102). The secondary power receiving device according to claim 1 or 2,
The secondary power receiving device, wherein the power receiving coil (11) has a rectangular outer shape. The secondary power receiving device according to any one of claims 1 to 3,
The secondary power receiving device, wherein the hollow portion of the power receiving coil (11) has an air core shape. The secondary-side power receiving device according to any one of claims 1 to 4,
A secondary-side power receiving device, characterized in that a thin wire is used as a wire constituting the power receiving coil (11). The secondary-side power receiving device according to any one of claims 1 to 5,
The secondary-side power receiving device, wherein the magnetic sheet (17) is made of a soft magnetic ferrite that generates an attractive force by the magnetic force of the positioning magnet (102). The secondary power receiving device according to any one of claims 1 to 6, further comprising:
A series capacitor (13) for constituting a resonance circuit connected in series with the power receiving coil (11),
A secondary-side power receiving device, wherein the capacitance of the series capacitor (13) is adjusted to a value that has a predetermined resonance frequency with the power receiving coil (11). The secondary power receiving device according to any one of claims 1 to 7,
The secondary-side power receiving device, wherein the secondary battery cell (12) installed on the back surface of the magnetic material sheet (17) is charged by the output from the rectification control circuit. The secondary power receiving device according to any one of claims 1 to 8, further comprising:
It has a rechargeable secondary battery cell (12),
The secondary power receiving device is:
While connected to a battery-driven device and supplying power for driving the battery-driven device from the secondary battery cell (12),
A secondary-side power receiving device that is a battery pack (10) that is placed on the charging base (100) and can be charged by receiving power from a power transmission coil built in the charging base (100). Charging stand (100),
There is a secondary power receiving device mounted on the charging stand (100) and capable of receiving power,
The charging stand (100)
A positioning magnet (102);
A power transmission coil (101),
With
The secondary power receiving device is:
A hollow power receiving coil (11) electromagnetically coupled to the power transmitting coil (101),
A rectification control circuit that rectifies and outputs the power received by the power receiving coil (11);
A magnetic sheet (17) disposed on the back surface of the power receiving coil (11);
With
The power receiving coil (11) is a state where the secondary side power receiving device is placed on the charging stand (100) so that a positioning magnet can be disposed in the hollow portion of the power receiving coil (11).
A charging stand and a secondary power receiving device, wherein an inner diameter of a hollow portion of the power receiving coil (11) is substantially equal to or larger than an outer diameter (DM) of a positioning magnet (102).

Images