JP2014186790A - Battery pack - Google Patents

Abstract

An object of the present invention is to avoid a situation where the battery pack becomes thick due to the winding method of a power receiving coil, and to make the battery pack thinner.
A battery pack is connected to a battery-powered device and supplies power for driving the battery-powered device, and is mounted on a charging base and receives power from a power transmission coil built in the charging base. A battery pack capable of contactless charging, a rechargeable secondary battery 2, a power receiving coil 1 electromagnetically coupled to a power transmitting coil built in a charging stand, and a surface of the power receiving coil 1 facing the power transmitting coil And a magnetic sheet 6 having magnetic permeability disposed on the back side of the sheet. The power receiving coil 1 is a planar coil in which a conductive wire 19 is simply wound, and has one end on the center side as the center lead wire 1a, one end on the outer periphery side as the outer lead wire 1b, and the center lead wire 1a from the center side. Pulled out to the outer periphery. The magnetic sheet 6 forms a storage space 9 for storing the lead-out portion of the center lead wire 1a.
[Selection] Figure 4

Description

  The present invention relates to a battery pack that is housed in a battery-powered device such as a mobile phone and can be charged in a contactless or wireless manner by being placed on a charging stand.

  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 battery pack that charges the battery by transferring power from the power transmission coil built in the charging stand to the power reception coil using the action of electromagnetic induction without connecting the contacts in this way has been developed. (See Patent Document 1).

  In Patent Document 1, a power transmission coil that is excited by an AC power source is built in a charging base, a power receiving coil that is electromagnetically coupled to the power transmission coil is provided in a battery pack, and the battery pack battery is powered by the power induced in the power receiving coil. Describes charging technology. The battery pack has a built-in charging circuit that rectifies the alternating current induced in the power receiving coil and supplies the battery to the battery for charging. According to this structure, a battery pack can be mounted on a charging stand, and a battery can be charged in a non-contact state without connecting contacts. 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 such a battery pack, as the portable device is further reduced in size, there is a strong demand for reduction in thickness. For this reason, a coil in which a wire is wound in a flat shape is also used. However, in the case of simple winding in which the power receiving coil is wound in a planar shape, the terminal end of the power receiving coil 201 is separated into the outer peripheral side and the center side as shown in FIG. For this reason, in order to conduct to the power receiving coil 201, it is necessary to draw one end of the coil from the center side to the outer peripheral side as a lead wire 202, and the lead wire 202 is arranged across the coil wound in a plane, As shown in FIG. 16, there is a problem that the power receiving coil 201 is partially thickened. In particular, in contactless charging, it is necessary to make the distance between the charging stand and the power transmission coil as short as possible. Therefore, the outer surface of the power receiving coil, that is, the surface facing the power transmission coil must be maintained flat. As a result, since the wires are overlapped on the back side, this portion is raised and the power receiving coil becomes thick, which causes a structural problem that obstructs the reduction in thickness.

JP 2008-66140 A

  The present invention has been made to solve such conventional problems. A main object of the present invention is to provide a battery pack that avoids a situation in which the battery pack becomes thick due to the winding method of the power receiving coil, thereby enabling the battery pack to be thinned.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, the battery pack according to the first aspect of the present invention is connected to a battery-driven device and supplies power for driving the battery-driven device, while being placed on a charging stand, A battery pack that can be contactlessly charged by receiving power from a power transmission coil built in a charging stand, and is a rechargeable secondary battery 2 and a power receiving coil 1 that can be electromagnetically coupled to the power transmission coil built in the charging stand. And a magnetic sheet 6 having magnetic permeability arranged on the back side of the surface of the power receiving coil 1 facing the power transmitting coil. The power receiving coil 1 is a planar coil in which a conductive wire 19 is simply wound. One end on the center side is a center lead wire 1a, and one end on the outer periphery side is an outer lead wire 1b, and the center lead wire 1a is the center. Pulled from the side to the outer periphery. The magnetic sheet 6 forms a storage space 9 for storing the lead-out portion of the center lead wire 1a. Thereby, the part where a planar coil becomes thick can be absorbed in the storage space of a magnetic material sheet, the situation where a battery pack becomes partially thick can be avoided, and thickness reduction can be maintained. Further, by holding the lead-out portion of the planar coil in the storage space, it is possible to suppress the unraveling of the conductive wire itself and suppress the coil from being unwound. In addition, by adopting simple winding, the diameter of the conductive wire can be increased compared with the method of winding two or more stages concentrically, so that the series resistance can be reduced. As a result, the planar coil itself There is also an advantage that the thickness can be reduced.

  Moreover, according to the battery pack which concerns on a 2nd side surface, the said storage space 9 can be formed by the groove-shaped recessed part 6a provided in the surface of the said magnetic body sheet 6. FIG. Thereby, thickening of the planar coil in the lead part of a center leader line can be absorbed with the simple composition of processing the surface of a magnetic material sheet partially. Furthermore, by making the storage space a recess provided on the surface of the magnetic material sheet, it is possible to prevent leakage magnetic flux from the magnetic material sheet and to suppress a decrease in magnetic permeability, and to provide an inexpensive planar coil or magnetic material sheet. The advantage is that it can be used.

  Moreover, according to the battery pack which concerns on a 3rd side surface, the said storage space 9 can be formed in the slit-shaped notch 6b which notched the said magnetic body sheet 6 partially. Thereby, the thickening of the planar coil in the lead part of a center leader line can be absorbed by the simple structure of notching a magnetic material sheet partially. Moreover, by making it a partial notch, the leakage magnetic flux from a magnetic material sheet can be reduced, the fall of a magnetic permeability can also be suppressed, and the advantage that an inexpensive planar coil and a magnetic material sheet can be utilized is acquired.

  Moreover, according to the battery pack which concerns on a 4th side surface, the said storage space 9 can be extended and provided from the center hole 1X of the said receiving coil 1 to the outer periphery of the magnetic material sheet 6. FIG. Thereby, the center leader line of the planar coil can be reliably pulled out from the center side to the outer peripheral side, and the planar coil can be reliably prevented from being partially thickened. Furthermore, processing can be simplified by extending one end of the storage space to the outer peripheral edge of the magnetic sheet.

  Moreover, according to the battery pack which concerns on a 5th side surface, the said receiving coil 1 can make an external shape square shape. As a result, the inductance can be increased by increasing the winding length of the power receiving coil. Further, since the rectangular coil can regulate the rotation direction of the coil as compared with the circular coil, positioning can be facilitated. Furthermore, the magnetic sheet can be made thinner by increasing the inductance of the power receiving coil.

  Further, according to the battery pack of the sixth aspect, the power receiving coil 1 is configured such that the center lead wire 1a and the outer peripheral lead wire 1b are positioned at corners of a square, and the magnetic sheet 6 is The storage space 9 can be positioned at a corner. As a result, the center lead wire and the outer lead wire drawn from the power receiving coil can be easily positioned, and can be reliably arranged at predetermined positions.

  In the battery pack according to the seventh aspect, the secondary battery 2 is a thin battery 2A, and the magnetic sheet 6 is interposed between the first flat surface 2a of the thin battery 2A and the power receiving coil 1. Can be arranged. Thereby, it is possible to effectively prevent the planar coil from being partially thickened while making the entire battery pack ideally thin.

  Further, according to the battery pack of the eighth aspect, the holder 8 for positioning the magnetic sheet 6 at a fixed position of the secondary battery 2 is provided, and the holder 8 is the first of the secondary battery 2. An upper surface plate portion 8X facing the flat surface 2a can be provided. Further, the upper plate portion 8X is provided with a coil arrangement hole 8A capable of accommodating the magnetic sheet 6, and is located at a position facing the accommodation space 9 of the magnetic sheet 6 disposed in the coil arrangement hole 8A. A lead wire step portion 8a for arranging the center lead wire 1a of the power receiving coil 1 can be provided. Thereby, even in the holder for positioning the magnetic sheet at the fixed position of the secondary battery, it is possible to effectively prevent the wiring portion of the center lead wire from becoming thick. Further, by providing the leader line step portion of the upper plate portion at a position facing the storage space of the magnetic sheet, the center lead line drawn from the power receiving coil can be smoothly wired from the storage space to the leader step portion.

  Further, according to the battery pack of the ninth aspect, the upper surface plate portion 8X divides the leader line step portion 8A into two by the step portion rib 8f, and the center lead out to the divided leader line step portion 8a. The line 1a and the outer peripheral lead line 1b can be partitioned and arranged. Thereby, the crossing and rubbing of the center leader line and the outer circumference leader line arranged in a divided manner can be eliminated, and fluttering can be suppressed and the lead can be stably extracted. In particular, it is possible to reliably prevent a situation in which the insulating coating is damaged due to contact between the center lead wire and the outer lead wire having a potential difference, resulting in a short circuit. Furthermore, by providing the step portion rib in the lead wire step portion, it is possible to effectively prevent and protect the center lead wire and the outer peripheral lead wire from being pressed by an external force.

  Moreover, according to the battery pack which concerns on a 10th side surface, the charging circuit which is arrange | positioned at the side surface 2c of the said secondary battery 2, converts the electric power received with the said receiving coil 1, and charges the said secondary battery 2 4, the power receiving coil 1 can draw out the center lead wire 1 a and the outer peripheral lead wire 1 b to the circuit board 5 side. Thereby, the connection path | route between a receiving coil and a circuit board can be shortened, and it can wire efficiently.

  Furthermore, according to the battery pack according to the eleventh aspect, the conductive wire 19 constituting the power receiving coil 1 can be a self-bonding wire. As a result, the planar coil formed by simply winding the conductive wire is very easily held in a predetermined shape, while effectively preventing adverse effects such as the coil wound in a planar shape being unwound from the winding end. Can be assembled well.

1 is a perspective view of a battery pack according to an embodiment of the present invention. It is a disassembled perspective view from the upper surface of the battery pack shown in FIG. It is a disassembled perspective view from the lower surface of a battery pack shown in FIG. It is a perspective view which shows the assembly battery which removed the battery case and the insulation seal from the battery pack shown in FIG. FIG. 5 is a plan view of the assembled battery shown in FIG. 4. FIG. 5 is an exploded perspective view of the assembled battery shown in FIG. 4. It is the VII-VII sectional view taken on the line of the assembled battery shown in FIG. It is an expanded sectional perspective view which shows an example of a receiving coil. It is an expanded sectional perspective view which shows another example of a receiving coil. It is a disassembled perspective view which shows another example of the storage space provided in a magnetic material sheet. It is a perspective view which shows the state which sets the battery drive apparatus incorporating a battery pack to a charging stand. FIG. 12 is a vertical cross-sectional view illustrating a state in which a battery driving device is set on the charging stand illustrated in FIG. 11 and the battery pack is charged. FIG. 13 is a vertical cross-sectional view showing a state where a battery pack is set on the charging stand shown in FIG. 12 and is charged. It is a circuit diagram which shows an example of the battery pack incorporated in the portable electronic device shown in FIG. It is a circuit diagram which shows an example of the battery pack shown in FIG. It is a perspective view which shows the receiving coil of the conventional battery pack.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack 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.
Example 1

Hereinafter, an example of a battery pack that is housed in a battery-driven device such as a mobile phone and can be charged in a contactless manner or wirelessly as a first embodiment will be described with reference to FIGS. In these drawings, FIG. 1 is a perspective view of the battery pack according to the embodiment, FIG. 2 is an exploded perspective view from the top view of the battery pack shown in FIG. 1, and FIG. 3 is a bottom view of the battery pack shown in FIG. 4 and 5 are a perspective view and a plan view showing the assembled battery with the battery case and the insulating seal removed from the battery pack shown in FIG. 1, and FIG. 6 is a top view of the assembled battery shown in FIG. FIG. 7 is a sectional view taken along line VII-VII in FIG. 4.
In the present specification, the vertical direction means the vertical direction in FIGS. In the battery pack shown in these drawings, a power receiving coil is arranged on the upper surface side in the drawing. However, when the battery pack is placed on the charging stand and receives power from the power transmission coil built in the charging stand and is contactlessly charged, the built-in power receiving coil is opposed to the power transmission coil, that is, The battery is set on the charging stand with the power receiving coil facing downward. Therefore, in the charged state, this battery pack is used by being placed on the charging stand in a posture opposite to the orientation shown in FIG.

The battery pack 50 shown in FIG. 1 to FIG. 7 is a rechargeable secondary battery 2, a power receiving coil 1 electromagnetically coupled to a power transmission coil built in a charging stand, and one surface of the power receiving coil 1. And a magnetic sheet 6 having magnetic permeability disposed on the back side of the surface facing the power transmission coil. A battery pack 50 shown in the figure is a circuit board in which a secondary battery 2, a power receiving coil 1, and a magnetic sheet 6 are integrally connected via a holder 8 and an electronic component for realizing a charging circuit 4 is mounted. 5 is integrally connected to a holder 8 to constitute an assembled battery 10. Further, the assembled battery 10 is packaged with a battery case 20 and an insulating seal 21 to form a battery pack 50. The battery pack 50 shown in FIG. 1 has a thin rectangular parallelepiped shape, and includes an output terminal 11 and a submergence determination label 22 for submergence determination on the left side surface of FIG. 1 as connection terminals for battery driving devices. Further, the battery pack 50 is provided with two positioning ribs 20f on the side surface on the output terminal 11 side for positioning the output terminal 11, and the battery pack 50 is attached to a fixed position of the battery drive device to connect the battery drive device. It can be connected securely.
(Secondary battery 2)

  The battery pack 50 incorporates a thin battery 2 </ b> A having a thin rectangular parallelepiped shape as the secondary battery 2. In this thin battery 2A, two large areas facing each other are defined as a first flat surface 2a and a second flat surface 2b. Further, the thin battery 2A is integrally formed with a side surface 2c and a side surface 2f that connect side edges of the first flat surface 2a and the second flat surface 2b. Furthermore, opposing terminal surfaces 2d and terminal surfaces 2e, which are end surfaces orthogonal to the first flat surface 2a and the second flat surface 2b, have electrode terminals of the thin battery 2A. The thin battery 2A has, as electrode terminals, a planar electrode (not shown) on the terminal surface 2d and a convex electrode 2g on the terminal surface 2e.

  Further, the thin battery 2A can be formed as a metal case by an outer can formed by integrally molding each surface. For example, the metal case can be aluminum or the like.

By using a lithium ion secondary battery or lithium polymer battery with a large volumetric energy density, the secondary battery 2 that is a thin battery 2A can be used as a portable drive device with a light, thin, and small overall size and good convenience. There are features. However, the secondary battery is not limited to this, and can be any rechargeable secondary battery such as a nickel metal hydride battery or a nickel cadmium battery.
(Receiving coil 1)

  The power receiving coil 1 is a planar coil obtained by simply winding a conductive wire 19 in a planar shape. A planar coil formed by winding the conductive wire 19 in a spiral shape is integrated with an adhesive or paint and held in a predetermined shape. Further, the planar coil in which the conductive wire 19 is further simply wound has one end on the center side as the center lead wire 1a and one end on the outer periphery side as the outer periphery lead wire 1b. The center lead wire 1a and the outer peripheral lead wire 1b drawn from the planar coil are connected to the circuit board 5 and input power supplied from the power transmission coil to the charging circuit 4 mounted on the circuit board 5. As described above, the planar coil in which the conductive wire 19 is wound in one layer has a feature that the thickness can be reduced and the battery pack 50 can be ideally reduced in thickness. As shown in FIGS. 2 to 6, the power receiving coil 1 that is a planar coil is fixed to the surface of the magnetic sheet 6 and disposed on the surface facing the power transmitting coil.

  It is important how the power receiving coil 1 can convert the magnetic flux from the power transmitting coil into an induced electromotive force, and how to increase the number of turns of the conductive wire 19 as the power receiving coil and the area to receive the magnetic flux is an issue. Become. Therefore, the power receiving coil 1 shown in the figure is a rectangular coil having a rectangular outer shape. Compared with the circular coil, the rectangular coil can make the outer periphery of the power receiving coil substantially equal to or less than the outer periphery of the magnetic sheet 6, and the length of the conductive wire 19 used as the coil can be extended from the circular coil. Thereby, the wire area which receives the magnetic flux from a power transmission coil can be increased, and it becomes possible to increase an induced current in connection with it. Further, the power receiving coil 1 having a rectangular outer shape has a larger center hole 1X which is a core portion of the coil, and thus the number of turns of the coil can be increased. For example, when the number of turns is 1.2 times, the voltage is 1.2 times and the induced electromotive force can be increased 1.2 times. However, the power receiving coil is not necessarily a rectangular coil, and may be a circular coil, an oval coil, or a polygonal coil.

Further, the conductive wire 19 used for the power receiving coil 1 is an insulated metal wire, and is a formal wire or enameled wire in which the wire material skin is insulated by an insulating film. The power transmission coil built in the charging stand causes a high frequency current to flow from a high frequency power source, generates a magnetic flux associated therewith, and the power receiving coil 1 receives the magnetic flux to generate an induced electromotive force by electromagnetic induction. The high frequency of the high frequency power supply can be set to, for example, 20 kHz to 1 MHz. Therefore, it is necessary to use the wire diameter in consideration of the skin effect as the wire diameter of the receiving coil 1 through which the high-frequency current flows. For example, in this Example 1, it is set as the insulated metal wire which insulated the copper wire. The conductivity of copper is 58 × 10 ⁶ S / m. Furthermore, when the transmission frequency of the power transmission coil is 200 kHz, the skin distance at which the high-frequency current is conducted to the copper wire by the skin effect is 0.147 mm. For this reason, the wire diameter of the insulated metal wire used here is a substantially circular wire having a skin distance doubled to about 0.3 mm. However, it is desirable that the wire diameter of the insulated metal wire as the power receiving coil be as thin as possible in order to make the battery pack thin, and the wire diameter should be reduced in order to enable rapid charging of the battery pack. Since it is also desired to increase the induced electromotive force, the wire diameter is not limited to the above.

  Further, the conductive wire 19 used for the power receiving coil 1 can be a self-bonding wire. The self-bonding wire is a wire material obtained by further covering a surface of an insulating metal wire obtained by insulating a wire skin with an insulating film, and further coating a molten layer. As this self-bonding wire, for example, the surface of an enameled wire provided with a resin film such as polyvinyl butyral or polyamide as a molten layer can be used. In this power receiving coil, the self-bonding wire is simply wound into a planar coil, and the surface coating is activated by heating or applying a solvent to fuse adjacent conductive wires together. It is held in a predetermined shape. Therefore, it is possible to efficiently assemble while effectively preventing adverse effects such as the coil wound in a flat shape being unwound from the winding end. Moreover, since it can hold | maintain to a predetermined shape, there also exists the characteristic which can be arrange | positioned, positioning correctly.

  Here, the power receiving coil 1 shown in FIG. 8 is a substantially rectangular planar coil in which the cross-sectional shape of the insulated metal wire which is the conductive wire 19 is substantially circular, and the conductive wires 19 are wound so as to be parallel to each other. Is forming. Here, the number of turns of the planar coil is twelve. However, the number of turns is not limited to this, and the number of turns can be changed so that the required voltage is obtained.

Next, FIG. 9 shows a modification of the power receiving coil. In this power receiving coil 71, the cross-sectional shape of the insulated metal wire, which is the conductive wire 79, is substantially rectangular, and the conductive wires 79 are wound so as to be parallel to each other to form a substantially rectangular planar coil. Here, the number of turns of the planar coil is set to twelve. However, the number of turns is not limited to this, and the number of turns can be changed so that the required voltage is obtained. As a result, the power receiving coil can increase the induced electromotive force by making the cross-sectional area of the diameter of the insulated metal wire approximately 1.27 times that of the insulated metal wire having a substantially circular cross-sectional shape. Can do.
(Magnetic sheet 6)

  The magnetic material sheet 6 is a sheet material containing a magnetic material, and is manufactured by molding a resin formed by adding powders of metal, carbon, ferrite, and the like into a sheet shape. The sheet-like magnetic material sheet 6 is laminated on the first flat surface 2a of the thin battery 2A, and the power receiving coil 1 is fixed to the surface of the magnetic material sheet 6, so that the magnetic material is applied to the first flat surface 2a of the thin battery 2A. The power receiving coil 1 is disposed via the body sheet 6. Thereby, the thin battery 2A can block the magnetic flux received by the power receiving coil 1 by the magnetic sheet 6 and suppress the influence on the outer can of the thin battery 2A due to the magnetic induction action. The magnetic material sheet 6 shown in FIGS. 2 to 6 has a substantially rectangular shape, and the rectangular power receiving coil 1 is laminated on the upper surface thereof.

  The magnetic sheet 6 is disposed at a fixed position of the secondary battery 2 through the holder 8. The holder 8 shown in the figure includes an upper surface plate portion 8X facing the first flat surface 2a of the secondary battery 2, and a coil arrangement hole 8A that can accommodate the magnetic sheet 6 is opened in the upper surface plate portion 8X. Provided. Therefore, the magnetic sheet 6 is inserted into the coil arrangement hole 8A provided in the upper plate portion 8X and arranged at a fixed position. This magnetic sheet 6 is provided with adhesive layers on both sides, and the magnetic sheet 6 is fixed to the first flat surface 2a of the thin battery 2A with an adhesive layer on one side. Thereby, even if the upper surface plate portion 8X of the holder 8 is not fixed to the first flat surface 2a of the thin battery 2A, the magnetic sheet 6 is inserted into the coil placement hole 8A and fixed to the thin battery 2A. Can prevent lateral displacement. Furthermore, this magnetic material sheet 6 can fix the receiving coil 1 with the adhesive layer on the opposite side.

  Further, the magnetic sheet 6 shown in the figure includes a storage space 9 for drawing out the center lead wire 1a which is one end on the center side of the power receiving coil 1. The storage space 9 shown in FIGS. 4 to 7 is formed by a groove-like recess 6 a provided on the surface of the magnetic sheet 6. The recess 6a is formed by partially thinning the surface of the magnetic sheet 6. As shown in FIGS. 6 and 7, the groove-shaped recess 6 a is formed on the outer peripheral edge of the magnetic sheet 6 from the center hole 1 </ b> X of the power receiving coil 1 so that the center lead wire 1 a of the power receiving coil 1 can be drawn to the outer peripheral side. It is extended to. The groove-like recess 6a formed in the magnetic sheet 6 has a depth (D) that is substantially equal to or slightly larger than the thickness (d) of the conductive wire 19 of the power receiving coil 1, so that the center lead line It is possible to reliably absorb the lead portion of 1a and prevent the planar coil from partially thickening. However, even if the depth (D) of the groove-shaped recess is shallower than the thickness (d) of the conductive wire of the power receiving coil, it is possible to reduce the partial thickness of the planar coil.

  As shown in FIGS. 4 to 7, in the magnetic sheet 6 having the storage space 9, the power receiving coil 1 is laminated in a state in which the center lead wire 1 a is guided in the storage space 9 that is a groove-like recess 6 a. Thereby, the receiving coil 1 can draw | extract the center leader line 1a to an outer peripheral side, without producing the level | step difference by the center leader line 1a. Furthermore, the storage space 9 which is the groove-shaped recess 6a can be pulled out while positioning the center lead wire 1a. The power receiving coil 1 shown in the figure is located at a corner of a square and draws out a center lead wire 1a. For this reason, the magnetic material sheet 6 shown in the figure is located at the corner of the quadrangle and is provided with a storage space 9. However, the power receiving coil does not necessarily have to draw out the lead wire at the corner of the square shape, and can be drawn out between the adjacent corners. The magnetic sheet on which the power receiving coils are laminated forms a storage space at a position opposite to the center lead wire drawn from the power receiving coil and in the middle of the adjacent corners.

Furthermore, as shown in FIG. 10, the storage space 9 can also be formed by a slit-shaped cut portion 6b in which the magnetic sheet 6 is partially cut. The magnetic sheet 6 is formed by cutting out a portion where the storage space 9 is provided into a slit shape having a width that can store the center lead wire 1a. This notch 6b is also provided extending from the center hole 1X of the power receiving coil 1 to the outer peripheral edge of the magnetic sheet 6 so that the center lead wire 1a of the power receiving coil 1 can be drawn to the outer peripheral side. Thus, by making the notch 6b into a slit shape, a decrease in magnetic permeability can be suppressed while reducing the leakage flux of the magnetic sheet 6. Furthermore, it can process easily by notching the magnetic material sheet 6 partially.
(Holder 8)

  The holder 8 is attached to the thin battery 2A, and covers the first flat surface 2a, the terminal surface 2e and the side surface 2c which are the end surfaces of the thin battery 2A. The holder 8 includes a rectangular upper surface plate portion 8X facing the first flat surface 2a of the thin battery 2A, a substrate insulating wall 8d facing one side surface 2c of the thin battery 2A, and one terminal of the thin battery 2A. An electrode insulating wall 8e facing the surface 2e is provided. The holder 8 shown in the figure connects one side of the square upper surface plate portion 8X and the side edge of the substrate insulating wall 8d to each other, and the side edge of the protruding portion 8g extending from one corner of the upper surface plate portion 8X. The electrode insulating wall 8e is connected to the side edge of the substrate insulating wall 8d, and the electrode insulating wall 8e is connected perpendicularly to the tip of the protruding portion 8g and the tip of the substrate insulating wall 8d.

  The upper surface plate portion 8X is provided with a coil arrangement hole 8A for fitting the magnetic material sheet 6 on which the power receiving coil 1 is mounted. The size of the coil placement hole 8A is approximately equal to or slightly larger than the outer shape of the magnetic material sheet 6 to be inserted, and the inner shape thereof is a substantially rectangular shape along the outer shape of the magnetic material sheet 6.

  Further, the upper surface plate portion 8X shown in FIGS. 4 to 6 has a leader step portion in which a central lead wire 1a and an outer peripheral lead wire 1b, which are two lead wires 1A drawn from the power receiving coil 1, are arranged at the corners. 8a is provided. The leader line step portion 8a is provided by forming the upper surface plate portion 8X of the holder 8 partially thinly. In this manner, by arranging the lead wire 1A on the lead wire step portion 8a provided by thinly forming the upper surface plate portion 8X, the wiring portion of the lead wire 1A is prevented from being partially thickened. The leader line step portion 8a is formed slightly deeper than or substantially equal to the thickness of the leader line 1A disposed here, and the leader line 1A disposed in the leader line step portion 8a is Protruding upward from the upper end surface of the upper plate portion 8X is prevented. The upper surface plate portion 8X shown in the drawing is provided with a leader line step portion 8a by forming the upper surface of the corner portion provided with the protruding portion 8g into a step shape. The upper surface plate portion 8X shown in the drawing extends to the protruding portion 8g and is provided with a leader line step portion 8a. The leader line step portion 8a is provided so as to extend from the opening edge of the coil arrangement hole 8A of the upper surface plate portion 8X to the outer peripheral edge which is a boundary edge with the substrate insulating wall 8d. In particular, the lead wire step 8 a for guiding the center lead wire 1 a is provided to extend to the opening edge facing the outer edge of the storage space 9 provided in the magnetic sheet 6. Thereby, the center leader line 1a arrange | positioned in the storage space 9 can be smoothly wired now.

  Further, the upper surface plate portion 8X shown in FIGS. 4 to 6 is provided with a step portion rib 8f at the center thereof to divide the lead line step portion 8a into two parts. The step rib 8f shown in the drawing is provided in such a posture as to cross the corner of the upper plate portion 8X from the opening edge of the coil arrangement hole 8A to the boundary edge with the substrate insulating wall 8d. It is divided into two areas. In the lead wire step 8 a, a central lead wire 1 a drawn from the center side of the power receiving coil 1 and an outer lead wire 1 b drawn from the outer peripheral side of the power receiving coil 1 are separately arranged in each divided region. . In this way, by dividing the two lead lines 1A drawn from the power receiving coil 1, it is possible to eliminate these crossings and rubbing, and to stably pull out while suppressing flapping. In particular, it is possible to reliably prevent a situation in which the insulating lead film is damaged due to contact between the central lead wire 1a and the outer peripheral lead wire 1b having a potential difference, resulting in a short circuit. The step portion rib 8f is formed such that the front end surface thereof is in contact with the inner surface of the upper surface 20X of the battery case 20, which will be described later, and is higher than the thickness of the lead wire 1A disposed in the lead wire step portion 8a. Yes. Thereby, when external force is applied to the battery case 20, it is possible to effectively prevent the battery case 20 from pressing the lead wire 1A and protect the lead wire 1A.

  As shown in FIGS. 2 and 3, the substrate insulating wall 8 d includes a substrate fixing portion 8 b and a substrate fixing portion 8 c that hold the circuit board 5 at both ends. Here, the board fixing part 8b and the board fixing part 8c are provided with a step slightly thicker than the thickness of the charging circuit 4 to be described later with respect to the board insulating wall 8d, and a protruding piece for preventing the circuit board 5 from falling off. It is provided above and below. The board insulating wall 8d connects the both ends of the circuit board 5 to the board fixing part 8b and the board fixing part 8c provided at both ends, and holds the circuit board 5 in a fixed position.

As shown in FIGS. 2 and 3, the electrode insulating wall 8e is disposed so as to face the terminal surface 2e of the thin battery 2A. The electrode insulating wall 8e in the figure forms an electrode hole 8B that exposes the convex electrode 2g. Furthermore, the electrode insulating wall 8e shown in the drawing is provided with positioning ribs 8h protruding outward along the lower end in the drawing. On the electrode insulating wall 8e, a terminal lead plate 12 and a connection lead plate 14 which will be described later can be easily arranged at a fixed position along the positioning rib 8h. Therefore, the terminal lead plate 12 and the connection lead plate 14 that connect the convex electrode 2g and the circuit board 5 are accurately positioned, and the adverse effects such as contact of the lead plate with the terminal surface 2e of the thin battery 2A are ensured. Thus, the connection can be easily performed.
(Circuit board 5)

  The circuit board 5 is disposed to face the side surface 2 c of the secondary battery 2. The circuit board 5 shown in the figure is disposed to face the side surface 2c on the side from which the two lead wires 1A are drawn from the power receiving coil 1. In other words, the power receiving coil 1 pulls out the center lead wire 1a and the outer periphery lead wire 1b to the circuit board 5 side. With this structure, the connection path between the power receiving coil 1 and the circuit board 5 can be shortened and wired efficiently. The holder 8 is provided with the above-described leader line step part 8 a extending to the connection part between the two leader lines 1 A and the circuit board 5. The center lead line 1 a drawn from the center side of the power receiving coil 1 passes through the storage space 9 formed on the surface of the magnetic sheet 6, and further through the lead line step portion 8 a of the holder 8. Connected to the coil terminal 3c. Furthermore, the outer peripheral lead wire 1 b drawn from the outer peripheral side of the power receiving coil 1 is connected to the coil terminal 3 d of the circuit board 5 via the lead wire step portion 8 a of the holder 8. Thereby, the induced electromotive force received by the power receiving coil 1 is conducted to the charging circuit 4 of the circuit board 5.

  Furthermore, the circuit board 5 has a charging circuit 4 potted with a thermosetting resin 17 on the side facing the side surface 2c of the thin battery 2A, and circuit terminals 3 for connecting lead plates and coils at both ends thereof. have. The charging circuit 4 is provided with a circuit for controlling the voltage, current, battery temperature and the like of the thin battery 2A. The circuit board 5 has an output terminal 11 on the surface opposite to the charging circuit 4. Thereby, since the circuit board 5 can control the voltage of this secondary battery cell 2, an electric current, a battery temperature, etc. and can implement charging / discharging, the battery pack 50 can be reduced in size.

  Further, the circuit board 5 is installed with a lead plate for connection to the positive and negative electrodes of the thin battery 2 </ b> A connected to the circuit terminal 3. Here, the circuit terminal 3 is separated into a lead terminal 3a, a lead terminal 3b, a coil terminal 3c, and a coil terminal 3d as shown in FIG. First, in one lead plate, a terminal lead plate 12 connected to the convex electrode 2g of the thin battery 2A is connected to the connection lead plate 14 via a PTC which is a protective element 13 responsible for temperature monitoring. The connection lead plate 14 has a bent piece 14a bent substantially vertically at an end opposite to the protective element 13, and the bent piece 14a is connected to the lead of the circuit board 5 shown in FIG. It is connected to the terminal 3a. However, it is also possible to mount the protective element on the circuit board and connect both ends of the circuit board to the thin battery with a lead plate or the like. In addition, the battery pack can connect the circuit board to the thin battery by using the protective element as a temperature fuse instead of the PTC and using one connection lead as the temperature fuse. Furthermore, the other lead plate has a terminal lead plate 15 connected to the planar electrode of the thin battery 2 </ b> A connected to the connection lead plate 16. The connection lead plate 16 has a bent piece 16 a bent substantially vertically at an end portion on the circuit board 5 side, and the bent piece 16 a is connected to the lead terminal 3 b of the circuit board 5. Thereby, the circuit board 5 can constitute a state in which positive and negative lead plates are integrated.

  The circuit board 5 integrated with the lead plate is placed on the board fixing portion 8b and the board fixing portion 8c of the holder 8, and the terminal lead plates 12 and 15 connected to both ends are convex and negative electrodes of the thin battery 2A. It is connected and fixed to the partial electrode 2g and the planar electrode. Thereby, the circuit board 5 can be installed only by connecting and fixing the positive and negative electrodes of the thin battery 2A and the lead plate, and the holder 8 can be easily installed and fixed to the thin battery 2A.

  Furthermore, since the board fixing part 8b and the board fixing part 8c are provided with a step, the thermosetting resin 17 of the circuit board 5 forms the gap 7 without contacting the board insulating wall 8d. For this reason, the electronic components on the circuit board 5 are integrally protected, and the heat dissipation of the electronic components can be enhanced by the gap 7.

Furthermore, since the battery pack 50 is electrically connected to the connection terminals 11 provided on the circuit board 5, even if pressed to contact the terminals of the external device, the battery pack 50 provides elasticity by providing a gap 7 so that the circuit is provided. There is also an advantage that the circuit board 5 can be protected by avoiding a situation in which a large load is applied to the board 5.
(Battery case 20 and insulating seal 21)

  The battery pack 50 insulates and protects the exterior of the assembled battery 10 with a battery case 20 that is integrally molded of plastic with the top surface and four side surfaces of the built-in secondary battery 2 except for the bottom surface as insulators. Furthermore, the battery pack 50 insulates and protects the internal secondary battery 2 and other circuits from the outside by insulating and protecting the bottom surface of the secondary battery 2 with a thin plastic insulating seal 21 that is an insulator. Yes. Also, the battery case 20 is formed with an electrode window 20A that exposes the output terminal 11 to the battery-driven device.

  The battery case 20 as insulation protection is integrally formed of plastic in which fibers such as glass fibers and carbon fibers are embedded. For example, PPS (polyphenylene sulfide) is suitable for this plastic. This PPS has excellent strength and can be reinforced with fibers to improve impact strength. Furthermore, since PPS is also excellent in flame retardancy, for example, when PPS is used as a battery case material, even if the plate thickness is reduced to 0.4 mm, the flame retardancy defined in UL standards and the like is related. The standard can be met. Therefore, PPS can make the battery case thinner while maintaining flame retardancy, and the size of the battery pack can be reduced accordingly. However, plastic such as polycarbonate can be used as the plastic for the battery case, and the plastic is not limited to PPS.

  Furthermore, the thin plastic insulating seal 21 can use an inexpensive material such as a polypropylene film or a polyethylene film as an insulating member.

  2 and 3 are exploded perspective views of the battery pack 50 of FIG. Here, the battery pack 50 has the assembled battery 10 in a state where the battery case 20 and the insulating seal 21 are removed. As shown in FIG. 3, the battery case 20 has a shallow container shape having an upper surface 20X facing the first flat surface 2a of the thin battery 2A obtained by thinning the secondary battery 2, and four side surfaces orthogonal to the upper surface 20X. The bottom side is the opening. Further, the battery case 20 has a board portion holding piece 20d having a shape for holding a circuit board 5 to be described later protruding on the bottom side of the side surface having the electrode window 20A. Furthermore, the battery case 20 has a battery part holding piece 20e for holding the thin battery 2A at the bottom of the side surface opposite to the electrode window 20A. Thereby, the battery case 20 inserts the circuit board 5 fixed to one side surface of the assembled battery 10 into the inside of the board portion holding piece 20d, and then the thin battery 2A located on the other side surface of the assembled battery 10. By inserting the battery part holding piece 20e on the side edge, it can be integrated with the assembled battery 10.

Furthermore, the battery case 20 integrated with the assembled battery 10 has an insulating sheet 21 fixed to the bottom surface side to close the opening of the battery case 20. The insulating sheet 21 is U-shaped as a whole and has a central portion fixed to the second flat surface 2b, which is the lower surface of the thin battery 2A. Furthermore, the U-shaped insulating sheet 21 fixes the first folded curved surface 21a and the second folded curved surface 21b, which are bent portions at both ends, to both side surfaces orthogonal to the side surface having the electrode window 20A. As shown in FIG. 2, the front ends of the first folded curved surface 21a and the second folded curved surface 21b are bent toward the upper surface 20X side of the battery case 20 to form a third folded curved surface 21c and a fourth folded curved surface 21d. It is fixed to the upper surface 20X. The third folded curved surface 21c and the fourth folded curved surface 21d are fixed to the sheet pasting groove 20a and the sheet pasting groove 20b provided on the upper surface 20X of the battery case 20. The insulating sheet 21 is fixed by providing the insulating sheet 21 with an adhesive surface or by separately applying an adhesive such as an adhesive. Thereby, the assembled battery 10 can be made into an integral structure by the battery case 20 and the insulating sheet 21. Further, the battery pack 50 is integrated, and the power receiving coil 1, the thin battery 2A, the circuit board 5, and the like included in the assembled battery 10 can be insulated and protected safely.
(Coil protection rib 20c)

  Furthermore, the battery pack 50 has a coil protection rib 20c that protrudes toward the core side of the power receiving coil 1 on the inner surface side of the upper surface 20X of the battery case 20, and the coil protection rib 20c is laminated on the lower end of the power receiving coil. It is set as the structure contact | abutted to the magnetic material sheet 6 which exists. Thereby, while protecting the receiving coil 1 from external force etc. with the battery case 20, the situation where the whole thickness becomes large can be avoided and size reduction of the battery pack 50 can be achieved. In particular, while the battery case 20 is thinned in order to maintain the electromagnetic coupling efficiency, the coil protection rib 20c can protect the receiving coil 1 from being damaged by the battery case 20 when an external force is applied. That is, by supporting the back surface side of the battery case 20, stress application to the power receiving coil 1 can be avoided, so that an advantage that the battery case 20 can be made thin and the power receiving coil 1 can be protected can be obtained. Further, if the resin battery case 20 is thickened at the core portion of the power receiving coil 1, sink marks are generated and the appearance is deteriorated. However, the coil protection rib 20 c is not provided on the entire surface of the battery case 20 but is partially provided. Generation | occurrence | production is suppressed and the situation where such an appearance worsens can also be avoided. Furthermore, the coil protection rib 20c can also position the power receiving coil 1 when the battery pack is assembled.

  The coil protection rib 20 c is sized to be disposed inside the center hole 1 </ b> X of the power receiving coil 1, and is formed to a height at which the lower surface, which is the tip, comes into contact with the magnetic material sheet 6. The battery case 20 shown in FIG. 3 is provided with a plurality of rows of ridges in parallel with each other as coil protection ribs 20c on the inner surface side of the upper surface 20X. The coil protection ribs 20c composed of a plurality of rows of ridges can be arranged inside the center hole 1X of the power receiving coil 1 with the length of each ridge being equal to or less than the inner diameter of the center hole 1X of the power receiving coil 1. In the power receiving coil 1 shown in the figure, since the shape of the center hole 1X is substantially square, the length of each protrusion is slightly shorter than one side of the square, and a plurality of protrusions are placed inside the center hole 1X. It can be arranged. Further, the plurality of rows of ridges are provided with their numbers and intervals adjusted so that they can be arranged inside the center hole 1X of the power receiving coil 1. The battery case 20 shown in the figure is provided with three rows of ridges to form coil protection ribs 20c. However, the coil protection ribs may have two or less ridges, or four or more rows. Furthermore, the coil protection rib is not necessarily limited to a shape in which a plurality of ridges are arranged in parallel to each other, but may have a shape that connects the plurality of ridges to each other, for example, a cross shape or a polygonal shape. In addition, the coil protection rib may be curved, or may be a shape obtained by connecting these, or a circular or elliptical ring shape.

  The above battery pack is connected to a battery-driven device and supplies power for driving the battery-driven device. The battery pack is placed on the charging stand, receives electric power from a power transmission coil built in the charging stand, and performs contactless charging of the built-in secondary battery. Here, FIG. 11 thru | or FIG. 13 shows the state charged with the charging stand 110 as an Example using the above battery pack. 11 and 12 show a state in which the battery driving device 100 containing the battery pack 80 is set on the charging stand 110 for charging, and FIG. 13 shows a state in which the battery pack 90 is directly set on the charging stand 110 for charging. Respectively.

  For example, the charging stand 110 includes a power transmission coil 113 that is electromagnetically coupled to the power receiving coils 1 of the battery packs 80 and 90, and a high frequency power source 114 that supplies high frequency power to the power transmission coil 113. Further, the high frequency power supply 114 is supplied with DC power from any of the connection plug 141, USB cable 142, and built-in battery 112 from an AC adapter (not shown). The contactless charging stand 110 has a DC input terminal 117 formed of a DC connection terminal 117 </ b> A for connecting a connection plug 141 from an AC adapter and a USB terminal 117 </ b> B for connecting a USB cable 142, provided in the exterior case 111. The DC input terminal 117 is charged to the internal battery 112 and directly supplied to the high frequency power source 114.

  Examples of circuit diagrams of the battery packs 80 and 90 are shown in FIGS. For example, the battery pack 80 of FIG. 14 can include the secondary battery 2, the power receiving coil 1, and a rectifier circuit 94 including a diode bridge that rectifies high-frequency power induced in the power receiving coil 1. The battery pack 80 outputs the direct current output from the rectifier circuit 94 to the device side circuit 101 provided in the battery driving device 100 to which the battery pack 80 is mounted. Furthermore, the battery pack 80 in this figure includes a protection FET 92 connected in series with the secondary battery 2 and a protection circuit 93 that protects the secondary battery 2 by controlling the protection FET 92 on and off. The protection circuit 93 switches the protection FET 92 on and off so as to prevent the secondary battery 2 from being overcharged and overdischarged. A battery-driven device 100 to which the battery pack 80 is attached has a built-in charge control circuit 105 for the secondary battery 2 in the device-side circuit 101. The charge control circuit 105 charges the secondary battery 2 with the DC power input from the rectifier circuit 94. Since the battery-driven device 100 inputs the DC power output from the rectifier circuit 94 to the charging control circuit 105 and charges the secondary battery 2, the DC power output from the rectifier circuit 94 is efficiently used as the secondary battery. 2 can be used for charging. In the case of the battery drive device 100 incorporating such a charge control circuit 105, the number of circuit components of the battery pack 80 can be reduced.

  Further, for example, the battery pack 90 of FIG. 15 incorporates a charging control circuit 95 for the secondary battery 2. The charge control circuit 95 fully charges the secondary battery 2 with the DC power output from the rectifier circuit 94. Further, the charge control circuit 95 includes a full charge detection circuit 96 that detects full charge of the secondary battery 2. The full charge detection circuit 96 outputs a full charge signal when the secondary battery 2 is fully charged. The full charge signal is output to the power receiving coil 1 and transmitted from the power receiving coil 1 to the power transmitting coil 113. The charging stand 110 has a built-in charging stop circuit (not shown) that detects a full charge signal output from the full charge detection circuit 96 and stops charging. When the full charge signal transmitted from the full charge detection circuit 96 of the battery pack 90 is detected, the charge stop circuit stops the supply of high-frequency power to the power transmission coil 113. The battery pack 90 transmits a full charge signal to the charging stand 110 when the secondary battery 2 is fully charged. Therefore, the charging stand 110 can stop the supply of high-frequency power to the power transmission coil 113 by detecting the full charge signal transmitted from the battery pack 90. For this reason, when the battery pack 90 is fully charged, the power supply to the high-frequency power source can be cut off to prevent wasteful power consumption. The battery pack 90 in this figure can be set on a charging stand and charged with the secondary battery 2 without being mounted on a battery-driven device such as a mobile phone.

  Although not shown in the circuit of FIG. 15, a circuit including the following authentication procedure may be used. This circuit transmits an ID signal (= (Identification) authentication signal) from the power transmission coil 113, is electromagnetically induced and receives the ID signal at the power receiving coil 1, and receives the ID signal on the battery pack 90 or the battery driving device 100 side. Charging is started when it can be confirmed and authenticated, and charging is stopped when the ID signal cannot be confirmed and authenticated. When the ID signal can be confirmed and authenticated by the battery pack 90 or the battery drive device 100, a signal (= ID confirmation signal) indicating that the ID signal has been confirmed is sent from the battery pack 90 or the battery drive device 100. Then, the power is transmitted to the power transmission coil 113 via the power receiving coil 1, and the ID confirmation signal is received on the charging stand 110 side including the power transmission coil 113, and the power supply is continued. When the ID confirmation signal cannot be received, it is recognized as a battery pack or battery-driven device that is not compatible with the charging stand 110, and power supply is stopped.

  The battery pack according to the present invention can be suitably used as a power source capable of contactless charging such as a mobile phone, a PDA, a portable game device, and a portable music player.

DESCRIPTION OF SYMBOLS 1 ... Power receiving coil 1X ... Center hole 1A ... Lead wire 1a ... Center lead wire 1b ... Outer lead wire 2 ... Secondary battery 2A ... Thin battery 2a ... First flat surface 2b ... Second flat surface 2c ... Side surface 2d ... Terminal surface 2e ... Terminal surface 2f ... Side surface 2g ... Projection electrode 3 ... Circuit terminal 3a ... Lead terminal 3b ... Lead terminal 3c ... Coil terminal 3d ... Coil terminal 4 ... Charging circuit 5 ... Circuit board 6 ... Magnetic sheet 6a ... Recess 6b ... Notch 7 ... Gap 8 ... Holder 8X ... Top plate 8A ... Coil placement hole 8B ... Electrode hole 8a ... Leader step 8b ... Substrate fixing part 8c ... Substrate fixing part 8d ... Substrate insulating wall 8e ... Electrode insulating wall 8f ... Step part rib 8g ... Projection part 8h ... Positioning rib 9 ... Storage space 10 ... Assembly battery 11 ... Output terminal 12 ... Terminal lead plate 13 ... Protection element 14 ... Connection lead plate 14a ... Bending piece 1 Terminal lead plate 16 Connection lead plate 16a Bent piece 17 Thermosetting resin 19 Conductive wire 20 Battery case 20X Upper surface 20A Electrode window 20a Sheet adhesive groove 20b Sheet adhesive groove 20c Coil protection rib 20d ... Substrate holding piece 20e ... Battery holding piece 20f ... Positioning rib 21 ... Insulating seal 21a ... First folding surface 21b ... Second folding surface 21c ... Third folding surface 21d ... Fourth folding surface 22 ... Submergence determination label 50 ... Battery pack 71 ... Receiving coil 79 ... Conductive wire 80 ... Battery pack 90 ... Battery pack 92 ... Protective FET
DESCRIPTION OF SYMBOLS 93 ... Protection circuit 94 ... Rectification circuit 95 ... Charge control circuit 96 ... Full charge detection circuit 100 ... Battery drive apparatus 101 ... Device side circuit 105 ... Charge control circuit 110 ... Charging stand 111 ... Outer case 112 ... Built-in battery 113 ... Power transmission coil 114: High frequency power supply 117 ... DC input terminal 117A ... DC connection terminal 117B ... USB terminal 141 ... Connection plug 142 ... USB cable 201 ... Power receiving coil 202 ... Lead wire

Claims (11)

While connected to the battery-driven device and supplying power to drive the battery-driven device,
A battery pack mounted on a charging stand and capable of contactless charging by receiving power from a power transmission coil built in the charging stand,
Rechargeable secondary battery (2),
A power receiving coil (1) that can be electromagnetically coupled to a power transmitting coil built in the charging stand;
Magnetic sheet (6) having magnetic permeability disposed on the back side of the surface facing the power transmission coil of the power receiving coil (1),
With
The power receiving coil (1) is a planar coil obtained by simply winding a conductive wire (19), with one end on the center side as a center lead (1a) and one end on the outer periphery as an outer lead (1b). The center lead line (1a) is drawn from the center side to the outer peripheral side,
The battery pack, wherein the magnetic sheet (6) forms a storage space (9) for storing a lead-out portion of the center lead wire (1a). The battery pack according to claim 1,
The battery pack, wherein the storage space (9) is formed by a groove-like recess (6a) provided on the surface of the magnetic sheet (6). The battery pack according to claim 1,
The battery pack, wherein the storage space (9) is formed by a slit-like notch (6b) obtained by partially notching the magnetic sheet (6). The battery pack according to any one of claims 1 to 3,
The battery pack, wherein the storage space (9) extends from a central hole (1X) of the power receiving coil (1) to an outer peripheral edge of the magnetic sheet (6). The battery pack according to any one of claims 1 to 4,
The battery pack, wherein the power receiving coil (1) has a rectangular outer shape. The battery pack according to claim 5,
The power receiving coil (1) positions the central lead wire (1a) and the outer peripheral lead wire (1b) at corners of a square shape, and the magnetic sheet (6) is provided in the storage space (9). A battery pack characterized by being positioned at a corner. The battery pack according to any one of claims 1 to 6,
The secondary battery (2) is a thin battery (2A), and the magnetic sheet (6) is disposed between the first flat surface (2a) of the thin battery (2A) and the power receiving coil (1). A battery pack characterized by comprising The battery pack according to claim 7, further comprising:
A holder (8) for positioning the magnetic material sheet (6) at a fixed position of the secondary battery (2);
The holder (8)
An upper plate portion (8X) facing the first flat surface (2a) of the secondary battery (2),
The upper plate portion (8X)
Coil arrangement hole (8A) that can accommodate the magnetic sheet (6) is provided,
Leader step portion for arranging the center lead wire (1a) of the power receiving coil (1) at a position facing the storage space (9) of the magnetic sheet (6) placed in the coil placement hole (8A). A battery pack comprising (8a). The battery pack according to claim 8, wherein
The upper surface plate part (8X) divides the leader line step part (8X) into two parts by a step part rib (8f), and the divided leader line step part (8a) and the center leader line (1a) and Battery pack formed by partitioning the outer peripheral lead wire (1b) The battery pack according to any one of claims 1 to 9,
A circuit board mounted on a side surface of the secondary battery (2) and mounted with a charging circuit (4) for converting the power received by the power receiving coil (1) and charging the secondary battery (2) ( 5)
The battery pack, wherein the power receiving coil (1) is configured such that the center lead wire (1a) and the outer periphery lead wire (1b) are drawn to the circuit board (5) side. The battery pack according to any one of claims 1 to 10,
The battery pack, wherein the conductive wire (19) constituting the power receiving coil (1) is a self-bonding wire.

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