JP6231061B2 - Receiving coil unit of non-contact power feeding device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a receiving coil unit of a non-contact power feeding device used for wirelessly charging a secondary battery built in a wearable device such as a smart watch and a manufacturing method thereof.

  In recent years, wearable devices (WPC) such as smart watches have been developed and sold. The wearable device has a built-in secondary battery for moving the device. When a wearable device is used and the remaining amount of electricity charged in the built-in secondary battery is low, the wearable device will not function. Before the value falls below the value, it is necessary to charge the secondary battery by supplying electricity to the secondary battery from an external power source.

  In the conventional general electric equipment, when charging the secondary battery by supplying electricity to the built-in secondary battery, connect the power cord from the external power supply to the electric equipment, and the built-in secondary battery In the wearable device, which is an advanced electrical device, it is a non-contact type that supplies power to the built-in secondary battery wirelessly from the viewpoint of smart power supply. A power feeder is used.

  Here, as shown in FIG. 6, the non-contact power supply apparatus includes a wearable device 100 and a power supply unit 102 that supplies electricity to the wearable device 100. The wearable device 100 includes a reception coil unit 104 and the power supply unit 102 includes a transmission coil unit 106. The power supply unit 102 includes a cord and an outlet for connecting to an external power source (not shown).

  When current is supplied to the power supply unit 102 from an external power source, the supplied current is supplied to the transmission coil unit 106 via an electronic circuit (not shown) of the power supply unit 102, and electromagnetic waves are transmitted from the transmission coil unit 106 to the wearable device 100. Is sent to The transmitted electromagnetic wave is received by the receiving coil unit 104 of the wearable device 100, converted into a current via an electronic circuit (not shown), and supplied to the secondary battery.

  By the way, since the wearable device 100 is a very small electric device, the built-in receiving coil unit 104 needs to be downsized. Further, in order to increase the transmission efficiency of electricity from the transmission coil unit 106 of the non-contact power feeding device to the reception coil unit 104 and shorten the charging time, it is necessary to increase the inductance L of the reception coil unit 104.

  In order to increase the inductance L of the receiving coil unit 104, it is necessary to increase the number of turns N of the receiving coil of the receiving coil unit 104. Increasing the number of turns N of the receiving coil by reducing the conducting wire of the receiving coil increases the AC resistance (ACR) of the receiving coil, increasing the heat generation of the receiving coil and lowering the transmission efficiency.

  That is, in the WPC coil, the inductance Ls is increased and the current is increased in order to increase the feed power. In order to improve the efficiency, it is necessary to reduce the high frequency loss. The high frequency loss can be evaluated by ACR (AC resistance Rs). High frequency loss is caused by skin effect, proximity effect, and the like.

  Therefore, various small receiving coil units 104 with high inductance L, low AC resistance (ACR) and high transmission efficiency have been proposed and used. However, the receiving coil unit 104 that has been proposed so far has a complicated structure, and it takes time and effort to manufacture, resulting in a high manufacturing cost.

  Also, the receiving coil unit 104 may be required to have a shape that can be incorporated into a wearable device, for example, a shade shape. When a round conducting wire is simply wound to form a flat disk-shaped receiving coil, and this receiving coil is formed into a substantially shade shape, the end of the conducting wire is likely to be scattered as shown in FIG. was there. If the conductive wires are hardened together with synthetic resin so that the ends of the conductive wires are not scattered, there is a problem that the receiving coil cannot be formed into a desired shape.

JP 2008-87733 A JP 2009-5469 A JP 2012-89618 A JP 2012-147638 A JP 2012-199432 A

The problem to be solved by the present invention is that an inductance L is large, an alternating current resistance (ACR) is small, and a receiving coil unit of a non-contact power feeding device that can be easily formed cannot be easily and inexpensively made.

  In order to prevent the AC resistance (ACR) from increasing even if the number of windings of the receiving coil is increased and the inductance L is increased, the present invention provides a receiving coil for a non-contact power feeding device by winding a strip-shaped rectangular wire in a spiral shape. The main feature is the formation of the unit.

  That is, the receiving coil unit of the non-contact power feeding device according to the present invention includes a ring-shaped receiving coil formed by winding a conducting wire in a spiral shape, and a substantially ring-shaped laminated and bonded to one surface of the receiving coil. A receiving coil substrate, and the conducting wire forming the receiving coil is made of a strip-shaped rectangular wire covered with a heat-fusible resin, and the adjacent conducting wires of the receiving coil are bonded and integrated with the heat-fusible resin. The receiving coil substrate has a terminal portion, a pair of terminals are formed on the terminal portion, and each end of the receiving coil is connected to the pair of terminals. Is.

  In addition, the method of manufacturing the receiving coil unit of the non-contact power feeding device according to the present invention includes a receiving coil forming step of forming a ring-shaped receiving coil by winding a conductive wire coated with a heat-fusible resin in a spiral shape under heating. A receiving coil substrate bonding step for bonding a receiving coil substrate to one surface of the receiving coil, and a soldering step for soldering each end of the receiving coil to a pair of terminals formed on the receiving coil substrate. It is characterized by having.

  Here, the adjacent conducting wires forming the receiving coil are laminated on the surface in the width direction including the long side of the cross section. The receiving coil is formed in a substantially shade shape, and adjacent conductive wires are sequentially shifted in the width direction and stacked. The width of the conducting wire is preferably 400 μm or more. The terminal portion protrudes from the inside of the reinforcing sheet. The receiving coil can be formed by a pressure forming machine.

  In other words, the width of the rectangular wire is preferably large in order to reduce the direct current resistance (DCR), but if it is increased, the number of turns of the coil cannot be obtained with a limited sbase, the inductance L cannot be secured, and the high frequency loss In order to reduce the thickness, it is considered that the same level as the skin depth is good. In order to suppress ACR and DCR, the coil width is small and the height is as large as possible.

  That is, the width of the rectangular wire is preferably large in order to reduce the direct current resistance (DCR), but if it is increased, the number of turns of the coil cannot be obtained in a limited space, the inductance L cannot be secured, and the high frequency loss In order to reduce the thickness, it is considered that the same level as the skin depth is good. In order to suppress ACR and DCR, the coil has a small width and a height as large as possible. For example, if the frequency is 350 KHz with a copper wire coil, the skin depth is about 110 μm. A coil having a width of 90 μm and a height of 400 μm has N = 26 (the number of turns), L = 20 μH, and a ferrite sheet with a thickness of 0.2 mm has L = 27 μH. Here, the width of the coil corresponds to the thickness of the coil, and the height of the coil corresponds to the thickness of the receiving coil.

  Since the present invention uses a strip-shaped rectangular wire as the conductor forming the receiving coil of the receiving coil unit, even when the adjacent conductors are slightly displaced when forming a flat receiving coil in accordance with the design requirements, There is an advantage that the overlapping can be maintained and the conductor can be molded without breaking the conductor, and thus the molded receiver coil unit can be provided at low cost.

  In addition, the receiving coil unit of the non-contact power feeding device of the present invention uses a strip-shaped rectangular wire as the conducting wire forming the receiving coil, so that the space factor of the conducting wire is increased, and the sectional area of the conducting wire can be increased, There is an advantage that a large current can be passed through the conductor, and thus the secondary battery of the wearable device can be rapidly charged.

  In addition, the receiving coil unit of the non-contact power feeding device of the present invention uses a strip-shaped rectangular wire as the conducting wire forming the receiving coil, so that the space factor of the conducting wire is increased, and the sectional area of the conducting wire can be increased, There is an advantage that a large current can be passed through the conducting wire, and thus heat generation during charging can be suppressed.

FIG. 1 is an explanatory diagram of a receiving coil unit of a non-contact power feeding apparatus according to the present invention. 2 is a cross-sectional view taken along arrow AA in FIG. FIG. 3 is a process diagram showing the manufacturing process of the receiving coil unit of the non-contact power feeding apparatus according to the present invention. FIG. 4 is an exploded perspective view of the receiving coil unit of the non-contact power feeding apparatus according to the present invention. FIG. 5 is a reference enlarged cross-sectional view of a conventional receiving coil. FIG. 6 is an explanatory diagram of a non-contact power feeding device.

  The present invention achieves the object of providing a receiving coil unit of a non-contact power feeding device for charging a secondary battery incorporated in a wearable device at a low cost with a minimum number of parts and without impairing electrical characteristics. .

  FIG. 1 is an explanatory view of a receiving coil unit of a contactless power feeding device according to the present invention, and FIG. 2 is an enlarged view of a terminal portion of the receiving coil unit of FIG. As shown in these drawings, the receiving coil unit of the non-contact power feeding device according to the present invention includes a ring-shaped receiving coil 10 and a ring-shaped receiving coil substrate 12 laminated and bonded to one surface of the receiving coil 10. It consists of.

  The receiving coil 10 is formed by winding a rectangular copper (Cu) wire in a spiral shape to form a ring shape, which is formed into a substantially shade shape. The outer diameter φ of the receiving coil is 20.95 mm, the inner diameter φ is 15 mm, the thickness is 400 μm, and the number of turns is 26.

  The width of the flat conducting wire forming the receiving coil 10 is 400 μm and the thickness is 90 μm. A flat conductor wire is covered with a polyurethane resin coating having excellent heat-fusibility. The thickness of the polyurethane resin film coated on the rectangular conductive wire is 20 μm. Adjacent flat conductors are bonded and integrated by a polyurethane resin coating. For example, if the frequency is 350 KHz with a flat copper wire, the skin depth is about 110 μm. When a receiving coil is formed of a rectangular conductor wire having a width of 90 μm and a height of 400 μm with the number of turns N = 26, L = 20 μH and L = 27 μH with a ferrite sheet. Here, the width of the coil corresponds to the thickness of the coil, and the height of the coil corresponds to the thickness of the receiving coil.

  The receiving coil substrate 12 includes a substrate sheet 14 and a pair of terminals 16 and 16 formed on the substrate sheet. The substrate sheet 14 is made of a polyimide resin (PI) sheet having a thickness of 25 μm. The substrate sheet 14 includes a ring-shaped main body portion 14a and a terminal portion 14b that is formed to protrude inside the main body portion 14a. The pair of terminals 16 and 16 are formed on the terminal portion 14b. The pair of terminals 16 and 16 are formed by applying gold plating to a base metal made of nickel (Ni).

  Next, the manufacturing method of the receiving coil unit of the non-contact electric power feeder which concerns on this invention is demonstrated, referring FIG.3 and FIG.4.

  First, the manufacturing method of the receiving coil unit of the non-contact power feeding device according to the present invention includes a receiving coil forming step for forming the receiving coil 10, a receiving coil substrate bonding step for bonding the receiving coil substrate 12 to the receiving coil 10, and a receiving A soldering step of soldering the winding start end 18 and winding end end 20 of the receiving coil 10 to the terminal 16 of the coil substrate 12 to form a receiving coil unit, and forming the receiving coil unit into a substantially shade shape. A receiving coil forming step.

  The receiving coil forming step is a step of forming a ring-shaped receiving coil 10 by winding a flat conducting wire in a spiral shape under heating using a winder. Here, the flat conducting wire is wound so that the surface in the width direction is parallel to the winding axis and the surface in the thickness direction is orthogonal to the winding axis. The polyurethane resin coating coated on the flat conductor is melted during winding, and the adjacent rectangular conductors of the formed receiving coil 10 are bonded and integrated by the polyurethane resin coating.

  The reception coil substrate bonding step is a step of bonding the reception coil substrate 12 to one surface of the reception coil 10 with an adhesive. In this step, an adhesive is uniformly and thinly applied to one surface of the receiving coil 10 and one surface of the receiving coil substrate 12, and the receiving coil is applied to one surface of the receiving coil 10 after an open time of about 1 minute. The receiving coil substrate 12 is bonded together by overlapping one surface of the substrate 12 and pressing it uniformly from above the receiving coil substrate 12 with the belly of the finger. When the reception coil substrate 12 is overlapped, the position of the winding start end 18 and the position of the winding end end 20 of the reception coil 10 and the positions of the terminals 16 and 16 of the reception coil substrate 12 are matched. deep.

  The soldering step is a step of soldering the winding start end 18 of the receiving coil 10 and the winding end 20 of the receiving coil 10 to a pair of terminals 16, 16 formed on the receiving coil substrate 12.

  The receiving coil forming step is a step of forming the receiving coil unit into a substantially shade shape using a compressed air vacuum forming machine. A PET sheet (t = 0.3 to 0.6 mm) is used as the forming sheet. The pneumatic pressure at the time of molding is 80 Mpa.

  In the receiving coil 10 according to the present invention, since the flat conductors overlap each other, even if the adjacent conductors are slightly displaced by molding, the overlapping portion is large (see FIG. 2), so that the conductors at the ends are broken. And can be formed into a substantially shade shape. Incidentally, when a round conducting wire is used as the conducting wire and the receiving coil 10 is formed by simply winding the round conducting wire, the end portion of the conducting wire is scattered as shown in FIG. Since there is a great possibility, it is extremely difficult to form a substantially shade-shaped receiving coil.

  The present invention can be applied not only to a use for charging a secondary battery of a wearable device such as a smart watch, but also to a use for charging a secondary battery such as a mobile phone, a smartphone, an ipad, or a portable music player.

DESCRIPTION OF SYMBOLS 10 Reception coil 12 Reception coil board | substrate 14 Board | substrate sheet | seat 14a Main-body part 14b Terminal part 16 Terminal 18 End part 20 of winding start End part of winding end

Claims (8)

A conducting wire comprising a ring-shaped receiving coil formed by winding a conducting wire in a spiral shape and a substantially ring-shaped receiving coil substrate laminated and bonded to one surface of the receiving coil, and forming the receiving coil Is coated with a heat-fusible resin, adjacent conductors of the receiving coil are bonded and integrated with a heat-fusible resin, the receiving coil substrate has a terminal portion, and the terminal portion has a pair of terminals. In the receiving coil unit of the non-contact power feeding device, wherein each end of the receiving coil is connected to the pair of terminals , the conductive wire is formed of a rectangular strip and the receiving coil is formed in a substantially umbrella shape. receiving coil unit of the contactless power feeding apparatus characterized by being.   2. The receiving coil unit of the non-contact power feeding device according to claim 1, wherein adjacent conducting wires forming the receiving coil are stacked on a surface in a width direction including a long side of a cross section. The receiving coil unit of the non-contact power feeding apparatus according to claim 1 , wherein the adjacent conducting wires of the receiving coil are sequentially shifted and laminated in the width direction . The receiving coil unit of the non-contact power feeding device according to claim 1 , wherein a width of the conducting wire is 400 μm or more . The receiving coil unit of the non-contact power feeding device according to claim 1 , wherein the terminal portion is formed to protrude inside the receiving coil substrate . A receiving coil forming step of forming a ring-shaped receiving coil by winding a conducting wire coated with a heat-fusible resin in a spiral shape under heating, and a receiving coil substrate bonding for bonding a receiving coil substrate to one surface of the receiving coil In the method of manufacturing a receiving coil unit of a non-contact power feeding apparatus, comprising: a step, and a soldering step of soldering each end of the receiving coil to a pair of terminals formed on the receiving coil substrate. A method of manufacturing a receiving coil unit of a non-contact power feeding apparatus, wherein the rectangular wire is used and the receiving coil is formed into a substantially shade shape . The method of manufacturing a receiving coil unit of a non-contact power feeding device according to claim 6 , wherein the conductive wires are wound so as to overlap each other on a plane in a width direction including a long side of a cross section . The method for manufacturing a receiving coil unit of a non-contact power feeding device according to claim 6 , wherein the receiving coil is formed by a compressed air molding machine .

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