WO2008133388A1

WO2008133388A1 - Contactless rechargeable battery capable of lessening power loss and battery charging set having the same

Info

Publication number: WO2008133388A1
Application number: PCT/KR2007/005822
Authority: WO
Inventors: Sub Han; Jung-Bum Kim; Ju-Yeon Jeong
Original assignee: Ls Cable, Ltd.
Priority date: 2007-04-25
Filing date: 2007-11-20
Publication date: 2008-11-06
Also published as: KR20080095643A; KR100903464B1

Abstract

The present invention relates to a contactless rechargeable battery having an embedded charging circuit for charging a battery cell with an electrical energy, comprising a high frequency alternating current inducing unit, in which a high frequency alternating current is induced by a magnetic field generated in an external contactless charger; a charging voltage supply unit for supplying voltage necessary to charge the battery cell; a charging current supply unit for supplying the battery cell with a charging current using the voltage applied from the charging voltage supply unit; and a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit, and transmitting the monitoring results to the external contactless charger through a wireless communication to induce change of intensity of the magnetic field.

Description

CONTACTLESS RECHARGEABLE BATTERY CAPABLE OF LESSENING POWER LOSS AND BATTERY CHARGING SET HAVING THE SAME

Technical Field

[1] The present invention relates to a contactless rechargeable battery that can be recharged using an electromagnetic induction phenomenon and a battery charging set having the same, and in particular, to a oontactless rechargeable battery that can prevent damage of internal components through feedback control and reduce unnecessary power consumption and a battery charging set having the same. Background Art

[2] Portable electronic devices such as mobile phones, PDAs or notebook oomputers are powered through rechargeable batteries. When voltage of the batteries drops below a predetermined level, users of the portable electronic devices recharges the batteries using battery chargers.

[3] Typically, the batteries of the portable electronic devices have connection terminals exposed to the external, so that the connection terminals of the batteries are electrically connected to charging terminals of the battery chargers. The batteries are recharged while the connection terminals of the batteries are electrically connected to the charging terminals of the battery chargers.

[4] Ffowever, the charging terminals and the connection terminals are exposed to the external for interconnection, and thus they are susceptible to impurity, when the charging terminals and the connection terminals are connected to each other, they are subject to wear by friction, and they are apt to corrode by moisture in the air, which results in poor connection between the charging terminals and the connection terminals. Further, in use of the batteries, if moisture percolates into the batteries through a crevice of the connection terminals, the batteries are completely discharged due to an electrical short of an internal circuit.

[5] To solve the problem, recently a contactless charging technique using an electromagnetic induction phenomenon is introduced to the batteries of the portable electronic devices. Currently, the contactless charging technique is widely used in daily necessities such as power toothbrushes or electric shavers.

[6] FIG. 1 is a schematic view illustrating configuration of a battery 50 and a charger 10 using a conventional oontactless charging technique.

[7] Referring to FIG. 1, the charger 10 includes a high frequency generating means 30 for receiving a source of electrical power from an alternating power supply 20 and outputting a high frequency alternating current, and a primary coil 40 for receiving the high frequency alternating current from the high frequency generating means 30 to form a magnetic field (M).

[8] And, the battery 50 includes a battery cell 60 charged with electrical energy, a secondary coil 70, in which the high frequency alternating current is induced by a flux linkage of the magnetic field (M) generated in the primary coil 40, a rectifier 80 for converting the induced high frequency alternating current into a direct current, and a constant voltage/constant current controller 90 for applying the direct current rectified in the rectifier 80 to the battery cell 60.

[9] Here, the constant voltage/constant current controller 90 is a well known circuit device used widely in a battery charging system. The constant voltage/constant current controller 90 supplies current to the battery cell 60 constantly at the beginning of charge, and when a charging voltage of the battery cell 60 exceeds a specific standard value, maintains the charging voltage constantly instead of reducing supply of the current.

[10] As shown in FIG. 2, the constant voltage/constant current controller 90 supplies a relatively larger charging voltage than a voltage when the battery is fully charged so as to charge the battery cell 60. However, as a residual amount of charging is smaller, the battery cell 60 forms a lower voltage, and thus the charging voltage supplied by the constant voltage/constant current controller 90 is set higher to charge the battery 50 fully. Therefore, loss of power αnirs as much as a difference between the charging voltage of the constant voltage/constant current controller 90 and the voltage of the battery cell 60.

Disclosure of Invention Technical Problem

[11] The present invention is designed to solve the problem, and therefore it is an object of the present invention to provide a oontactless rechargeable battery, in which a charging voltage for charging the battery is supplied actively depending on the change of voltage of a battery cell, and a battery charging set having the same. Technical Solution

[12] In order to achieve the above-mentioned object, a contactless rechargeable battery according to an aspect of the present invention, having an embedded charging circuit for charging a battery cell with an electrical energy, comprises a high frequency alternating current inducing unit, in which a high frequency alternating current is induced by a magnetic field generated in an external contactless charger; a charging voltage supply unit for supplying voltage necessary to charge the battery cell; a charging current supply unit for supplying the battery cell with a charging current using the voltage applied from the charging voltage supply unit; and a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit, and transmitting the monitoring results to the external oontactless charger through a wireless communication to induce change of intensity of the magnetic field.

[13] The high frequency alternating current inducing unit may be a coil, with which a magnetic flux of the magnetic field generated from the external contactless charger links.

[14] The charging current monitoring unit may include a wireless sending unit for wirelessly propagating the monitoring results through an antenna; and a current detecting unit for measuring the current supplied to the battery cell by the charging current supply unit. Further, the charging current monitoring unit may further include a microprocessor for generating and outputting an adjustment request signal for requesting the oontactless charger to change the intensity of the magnetic field.

[15] The magnetic field generated in the oontactless charger may be generated disoon- tiniDusly, the charging current monitoring unit may further include a charging pause detecting unit for receiving the high frequency alternating current outputted from the high frequency alternating current inducing unit, detecting a point of time when the induction of the high frequency alternating current is terminated, and outputting the point of time to the microprocessor, and the monitoring results may be transmitted to the external contactless charger through the wireless communication while the induction of the high frequency alternating current is not made after the point of time is inputted.

[16] And, the oontactless rechargeable battery may further comprise an allowable current setting unit for setting a maximum value of the charging current supplied by the charging current supply unit, and the allowable current setting unit may set the maximum value of the charging current in consideration of a charging current necessary when charging the battery cell with the charging current of the charging current supply unit.

[17] The charging current supply unit may be a transistor. [18] According to anther aspect of the present invention, a oontactless charging set comprises a oontactless rechargeable battery and a contactless charger, the oontactless rechargeable battery includes a high frequency alternating current inducing unit, in which a high frequency alternating current is induced by a magnetic field generated in the external oontactless charger, a charging voltage supply unit for supplying voltage necessary to charge a battery cell, a charging current supply unit for supplying the battery cell with a charging current using the voltage applied from the charging voltage supply unit, and a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit, and transmitting the monitoring results to the external contactless charger through a wireless communication to induce change of intensity of the magnetic field, and the contactless charger includes a magnetic field generating unit for receiving an alternating current to form a magnetic field in an external space, a high frequency power driving unit for applying disoon- tinixmsly a high frequency alternating current to the magnetic field generating unit, and a charging power adjusting unit for receiving the monitoring results through a wireless communication while the high frequency alternating current is not applied to the magnetic field generating unit, and controlling the high frequency power driving unit to adjust power of the high frequency alternating current applied to the magnetic field generating unit to adjust a charging power transmitted to the battery.

[19] The high frequency alternating current inducing unit may be a coil, with which a magnetic flux of the magnetic field generated from the external contactless charger links.

[20] The charging current monitoring unit may include a wireless sending unit for wirelessly propagating the monitoring results through an antenna; and a current detecting unit for measuring the current supplied to the battery cell by the charging current supply unit. Further, the charging current monitoring unit may further include a microprocessor for generating and outputting an adjustment request signal for requesting the oontactless charger to change the intensity of the magnetic field.

[21] Preferably, the magnetic field generated in the contactless charger is generated dis- continuausly, the charging current monitoring unit further includes a charging pause detecting unit for receiving the high frequency alternating current outputted from the high frequency alternating current inducing unit, detecting a point of time when the induction of the high frequency alternating current is terminated, and outputting the point of time to the microprocessor, and the monitoring results are transmitted to the external contactless charger through the wireless communication while the induction of the high frequency alternating current is not made after the point of time is inputted.

[22] The magnetic field generating unit may be a coil, to which the high frequency alternating current is applied at both ends thereof.

[23] The charging power adjusting unit may include a wireless receiving unit for receiving the monitoring results through an antenna; and a microprocessor for receiving the monitoring results from the wireless receiving unit and controlling the high frequency power driving unit to adjust power of the high frequency alternating current applied to the magnetic field generating unit.

[24] The contactless charger may further include a power supply unit for receiving and converting an alternating current into a direct current and supplying the direct current to the high frequency power driving unit, and the high frequency power driving unit may include a pulse signal generating unit for receiving a pulse drive signal from a microprocessor and outputting a pulse signal; and a power driving unit for receiving the pulse signal and switching rapidly the direct current supplied by the power supply unit to generate a pulse type high frequency alternating current.

[25] The power supply unit may include an overvoltage overcurrent protecting cirαdt for receiving an alternating current and intercepting an overvoltage current; a rectifying unit for rectifying the alternating current passed through the overvoltage overcurrent protecting circuit and converting the rectified alternating current into a direct current; and a constant voltage supply unit for receiving the converted direct current and outputting a constant voltage current.

[26] Preferably, the high frequency power driving unit applies discontinuαusly the high frequency alternating current to the magnetic field generating unit, and the charging power adjusting unit receives the monitoring results while the high frequency alternating current is not applied to the magnetic field generating unit.

[27] The charging power adjusting unit may perform pulse width modulation, pulse frequency modulation, pulse amplitude modulation or pulse number modulation to adjust the charging power.

[28] The contactless rechargeable battery may further include an allowable current setting unit for setting a maximum value of the charging current supplied by the charging current supply unit, and the allowable current setting unit sets the maximum value of the charging current in consideration of a charging current necessary when charging the battery cell with the charging current of the charging current supply unit.

[29] The charging current supply unit may be a transistor. Brief Description of the Drawings

[30] The present invention will be more fully described in the following detailed description, taken accompanying drawings, however, the description proposed herein is just a preferable example for the purpose of illustrations, not intended to limit the scope of the invention. In the drawings:

[31] FIG. 1 is a schematic configuration view illustrating a battery and a charger using a conventional contactless charging technique.

[32] FIG. 2 is a graph illustrating changes in charging voltage and battery voltage according to time in the prior art.

[33] FIG. 3 is a block diagram illustrating a oontactless charger and a oontactless rechargeable battery according to a preferred embodiment of the present invention.

[34] FIG. 4 is a detailed block diagram illustrating a configuration of the contactless charger of FIG. 3.

[35] FIG. 5 is a detailed block diagram illustrating a configuration of the contactless rechargeable battery of FIG. 3.

[36] FIG. 6 is a graph illustrating voltage-current characteristics of a charging current supply unit according to a preferred embodiment of the present invention.

[37] FIG. 7 is a circuit diagram illustrating the charging current supply unit and an allowable current setting unit according to a preferred embodiment of the present invention.

[38] FIG. 8 is a graph illustrating changes in charging voltage and battery voltage according to time according to a preferred embodiment of the present invention.

[39] FIG. 9 is a graph illustrating schematically a charging current outputted discon- tiniDusry from a secondary coil of the oontactless rechargeable battery. Best Mode for Carrying Out the Invention

[40] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications oould be made thereto without departing from the spirit and soope of the invention.

[41] FIG. 3 is a block diagram illustrating a oontactless charger (C) and a oontactless rechargeable battery (B) according to a preferred embodiment of the present invention.

[42] Referring to FIG. 3, the contactless charger (C) according to a preferred embodiment of the present invention includes a primary coil 200 for generating a magnetic field, a high frequency power driving unit 210, a primary antenna 220, a wireless receiving unit 230, a microprocessor 240 and a power supply unit 260.

[43] The high frequency power driving unit 210 applies tens kHz of high frequency alternating current to the primary coil 200 through a high speed switching operation to generate a magnetic field. For example, the high frequency power driving unit 210 applies 80 kHz of high frequency alternating current to the primary coil 200. When the magnetic field is generated in the primary coil 200 by the high frequency alternating current, a charging power is transmitted to the battery (B) in a contactless manner by an electromagnetic induction phenomenon.

[44] Preferably, the high frequency power driving unit 210 may be a well known SMPS

(Switching Mode Power Supply), however the present invention is not limited in this regard.

[45] The wireless receiving unit 230 receives a measured current value transmitted wirelessly from the battery (B) through the primary antenna 220 and inputs the measured current value into the microprocessor 240.

[46] Preferably, a carrier wave of 10 to 15 MHz is used to transmit wirelessly the measured current value.

[47] Preferably, when the measured current value is transmitted wirelessly from the battery (B), the high frequency alternating current is not applied to the primary coil 200. This is because if an adjustment request signal is transmitted wirelessly in such a state that a magnetic field is generated by application of high frequency alternating current of tens kHz, the measured current value is screened by the magnetic field, and thus the measured current value is not received through the wireless receiving unit 230.

[48] Therefore, the high frequency power driving unit 210 does not apply continuously the high frequency alternating current to the primary coil 200, but puts pause periods between charge periods cyclically. For example, when the charging power is transmitted to the battery (B), the high frequency power driving unit 210 does not apply the high frequency alternating current to the primary coil 200 during 50 ms at interval of 3 seconds. In this case, the measured current value is wirelessly transmitted within 50 ms when the high frequency alternating current is not applied to the primary coil 200.

[49] The wireless receiving unit 230 and the microprocessor 240 provide a charging power adjusting unit. The microprocessor 240 controls the entire operation of the charger (C), and in particular, when receiving the measured current value of the charging current from the wireless receiving unit 230, the microprocessor 240 controls the high frequency power driving unit 210 to adjust power of the high frequency alternating current applied to the primary coil 200.

[50] Preferably, the microprocessor 240 controls the high frequency power driving unit

210 to perform pulse width modulation, pulse frequency modulation, pulse number modulation or pulse amplitude modulation, thereby adjusting power of the high frequency alternating current. Thus, a level of the charging current transmitted to the battery (B) is adjusted to prevent damage of an internal circuit of the battery (B).

[51] The power supply unit 260 receives and converts an alternating current 250 into a direct current, and supplies an operating power to the high frequency power driving unit 210 and the microprocessor 240.

[52] The contactless rechargeable battery (B) according to a preferred embodiment of the present invention includes a charging circuit module having a secondary coil 300 for inducing a high frequency alternating current, a charging voltage supply unit 310, a charging current supply unit 320, a current detecting unit 330, a wireless sending unit 340 and a secondary antenna 350, and a battery cell 400 charged by the charging circuit module.

[53] While the high frequency alternating current is applied to the primary coil 200 of the charger (C), the high frequency alternating current is induced in the secondary coil 300 by an electromagnetic induction phenomenon. At this time, a dimension of the high frequency alternating current induced in the secondary ooil 300 is in proportion to a magnetic flux linked with the secondary coil 300.

[54] The charging voltage supply unit 310 smoothes out the high frequency alternating current induced in the secondary coil 300, oonverts the high frequency alternating current into a direct current, and supplies a charging voltage for charging the battery cell 400.

[55] The charging current supply unit 320 is configured to supply a charging current in proportion to a difference (ΔV) between voltage (V ) supplied by the charging voltage supply unit 310 and voltage (V ) charged to the battery (B).

2

[56] The current detecting unit 330 and the wireless sending unit 340 provide a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit 320, and transmitting the monitoring results to the charger (C).

[57] The current detecting unit 330 measures continujusly a value of the current supplied to the battery cell 400 by the charging current supply unit 320, and provides the measured current value to the wireless sending unit 340. For example, the current detecting unit 330 may be a circuit having a resistance device for measuring the current value.

[58] The wireless sending unit 340 modulates the measured current value outputted from the current detecting unit 330 and wirelessly transmits the measured current value through the secondary antenna 350 to the primary antenna 220 of the wireless receiving 230 of the charger (C). At this time, a carrier wave of 10 to 15 MHz is used.

[59] When the measured current value is transmitted to the charger (C), power of the high frequency alternating current outputted through the high frequency current driving unit 210 is increased or decreased by control of the microprocessor 240. As a result, the power of the high frequency alternating current induced in the secondary coil 300 by an electromagnetic induction phenomenon is increased or decreased. Accordingly, the voltage supplied by the charging voltage supply unit 310 is increased or decreased. Preferably, feedback control on the power of the high frequency alternating current applied to the primary coil 200 is made continuously until the voltage supplied by the charging voltage supply unit 310 is the same as the charging voltage of the battery cell 400.

[60] Preferably, the contactless rechargeable battery (B) may further include a microprocessor (not shown), and in consideration of the measured current value received from the current detecting unit 330 and the difference value between the voltage supplied by the charging voltage supply unit 310 and the charging voltage of the battery (B), the microprocessor (not shown) may generate and transmit an adjustment request signal to the charger (C) so that a value of the current supplied by the charging current supply unit 320 is increased or decreased corresponding to the difference value. Then, the microprocessor 240 of the charger (C) controls the output of the high frequency power driving unit 210 with reference to the adjustment request signal received through the wireless receiving unit 230.

[61] Alternatively, the microprocessor 240 of the charger (C) may have a function of a microprocessor (not shown) of the contactless rechargeable battery (B). That is, the contactless rechargeable battery (B) transmits the measured current value detected by the current detecting unit 330 through the wireless sending unit 340 to the charger (C), and in consideration of the difference value between the voltage supplied by the charging voltage supply unit 310 and the charging voltage of the battery (B), the microprocessor 240 may control the output of the high frequency power driving unit 210 using the measured current value received through the wireless receiving unit 230 so that a value of the current supplied by the charging current supply unit 320 is increased corresponding to the difference value.

[62] FIG. 4 is a detailed block diagram illustrating a configuration of the contactless charger (C) of FIG. 3.

[63] Referring to FIG. 4, the power supply unit 260 includes an overvoltage overcurrent protecting circuit 260a for intercepting overvoltage applied from the alternating current 250, a rectifying unit 260b for converting the alternating current passed through the overvoltage overcurrent protecting circuit 260a into a direct current, and a oonstant voltage supply unit 260c for receiving the rectified direct current and supplying a constant voltage direct current to the microprocessor 240 and the high frequency power driving unit 210.

[64] The high frequency power driving unit 210 includes a pulse signal generating unit

(Pulse Width Modulation) 210a for receiving a pulse drive signal from the microprocessor 240 and generating a pulse signal, and a power driving unit 210b for switching rapidly the constant voltage direct current inputted from the constant voltage supply unit 260c by the pulse signal outputted from the pulse signal generating unit 210a to generate and apply a high frequency alternating current to the primary coil 200.

[65] FIG. 5 is a detailed block diagram illustrating a configuration of the contactless rechargeable battery (B) of FIG. 3.

[66] Referring to FIG. 5, the contactless rechargeable battery (B) according to a preferred embodiment of the present invention includes a charging voltage supply unit 310 having a rectifying unit 311 for converting the high frequency alternating current induced in the secondary coil 300 into a direct current and a voltage supply unit 312 for supplying a charging voltage necessary to charge the battery cell 400 using the rectified direct current, and a charging current supply unit 320 having a current supply unit 321 for converting the voltage received from the voltage supply unit 312 into a charging current.

[67] The charging current supply unit 320 is configured to supply the charging current in proportion to the difference (ΔV) between the voltage (V ) supplied by the voltage supply unit 312 and the voltage (V ) charged to the battery (B) (Refer to FIG. 6).

2

[68] Preferably, the charging current supply unit 320 may further include an allowable current setting unit 322 for setting a maximum limit of the charging current supplied by the current supply unit 321. The allowable current setting unit 322 is configured to set a maximum value (I ) of the charging current supplied by the current supply ch max unit 321 in consideration of state that the difference value (ΔV) between the voltage (V ) supplied by the voltage supply unit 312 and the voltage (V ) charged to the battery (B) is maximum (ΔV ) (i.e. the battery cell 400 is completely discharged). max

[©] Preferably, the current supply unit 321 may be a PNP type transistor (Refer to FIG.

7). In this case, an emitter (Tr ) of the PNP type transistor may be connected to an e output terminal of the voltage supply unit 312, a collector (Tr ) may be connected to a terminal of the battery cell 400, a base (Tr ) may be connected to the allowable current b setting unit 322. For example, the allowable current setting unit 322 may be a variable resistance or a transistor, and may be connected to the base (Tr ) of the PNP type b transistor. [70] Finally, a device of the power supply unit 321 consumes power as much as the difference value (ΔV) between the voltage (V ) supplied by the voltage supply unit 312 and the voltage (V ) charged to the battery (B), and thus loss of power occurs (Refer to FIG. 8). According to an embodiment, the present invention can detect the current flowed into the battery cell 400 and supply a charging voltage of dimension necessary to charge the battery cell 400, and thus the present invention does not provide unnecessary charging voltage and can supply actively the charging voltage (V ) depending on the change of voltage (V ) charged to the battery cell 400. Therefore,

2 the present invention can minimize the loss of power supplied for charging the battery cell 400.

[71] Meanwhile, the current value or adjustment request signal detected by the current detecting unit 330 is transmitted to the charger (C) through the wireless sending unit 340, and in the case that the adjustment request signal is propagated wirelessly while the charging power is transmitted from the primary coil 200 of the charger (C) to the secondary coil 300 of the battery (B), the adjustment request signal is screened by the magnetic field generated from the primary coil 200. Thus, to solve the problem, when transmitting the charging power from the charger (C) to the battery (B), the present invention pauses temporarily the transmittance of the charging power at a regular cjcle.

[72] In other words, as shown in FIG. 9, the present invention repeats cyclically charge periods (Δt ) where charging is made by inducing the high frequency alternating

A current in the secondary coil 300 by an electromagnetic induction phenomenon, and pause periods (Δt ) where the charging is paused by temporarily stopping application

B of the high frequency alternating current with intention. And, while the charging is paused by stopping the induction of the high frequency alternating current in the secondary coil 300, the adjustment request signal of the charging power is transmitted to the charger (C).

[73] For this purpose, the battery (B) according to an embodiment of the present invention includes a charging pause detecting unit 360 for receiving the high frequency alternating current induced in the secondary coil 300 and detecting a point of time when the charge period is terminated (Refer to t of FIG. 9).

[74] The charging pause detecting unit 360 detects and inputs the termination point of time of the charge period (Refer to t of FIG. 9) into the wireless sending unit 340. s

Then, the wireless sending unit 340 transmits wirelessly the measured current value or adjustment request signal to the charger (C) while the charging power is not transmitted. Accordingly, it can prevent the measured current value or adjustment request signal from being screened by the magnetic field generated by the primary coil 200.

[75] When the adjustment request signal of the charging power is transmitted wirelessly to the charger (C), power of the high frequency alternating current applied to the primary coil 200 is adjusted by the feedback control as mentioned above, so that the charging voltage supply unit 310 can maintain voltage of both ends thereof to a proper level.

[76] The above-mentioned contactless charger (C) and battery (B) according to the present invention can supply actively the charging voltage (V ) depending on the change of voltage (V ) charged to the battery cell 400.

[77] Hereinafter, operation of the oontactless charger (C) and battery (B) according to the present invention is described in detail with reference to the above-mentioned elements.

[78] First, in the case of a noncharge mode, the high frequency power driving unit 210 of the charger (C) applies a high frequency alternating current to the primary coil 200 during a short time at regular intervals of time by control of the microprocessor 240. For example, the high frequency power driving unit 210 applies a high frequency alternating current of 80 kHz for 500 ms at intervals of 1 seoond. Then, the primary coil 200 generates a magnetic field whenever the high frequency alternating current is applied.

[79] A user places the battery (B) on the charger (C) to charge the battery (B). After the battery (B) is located in place, when the high frequency alternating current is applied to the primary coil 200 of the charger (C) for a predetermined time, a magnetic field is generated in the primary coil 200, and as a result, a magnetic flux links with the secondary coil 300 of the battery (B). Accordingly, the high frequency alternating current is induced in the secondary coil 300 for a predetermined time, and when the high frequency alternating current is not applied to the primary coil 200, the induction of the high frequency alternating current is temporarily paused by loss of the magnetic field.

[80] Meanwhile, the charging pause detecting unit 360 detects a point of time when the induction of the high frequency alternating current is temporarily paused, and inputs the point of time to the wireless sending unit 340. Then, the wireless sending unit 340 modulates a current value inputted from the current detecting unit 330 and transmits wirelessly the current value to the charger (C) through the secondary antenna 350. At this time, the wireless sending unit 340 transmits a response signal. Here, the response signal informs the microprocessor 240 of the charger (C) that the secondary coil 300 of the battery (B) is linked with the magnetic field generated in the primary coil 200 of the charger (C).

[81] When the measured current value and the response signal are transmitted wirelessly, the wireless receiving unit 230 of the charger (C) demodulates and inputs the response signal into the microprocessor 240. Then, the microprocessor 240 begins to transmit the charging power to the battery (B). That is, the microprocessor 240 controls the high frequency power driving unit 210 to repeat the application of the high frequency alternating current to the primary coil 200 and pause of the application of the high frequency alternating current for a predetermined time. For example, the high frequency power driving unit 210 applies a high frequency alternating current of 80 kHz for 3 seconds and pauses the application of the high frequency alternating current for 50 ms.

[82] While the high frequency alternating current is applied to the primary coil 200, the high frequency alternating current is also induced in the secondary coil 300 of the battery (B) by an electromagnetic induction phenomenon. The time when the induction of the high frequency alternating current in the secondary coil 300 continues is substantially the same as the time when the application of the high frequency alternating current to the primary coil 200 continues.

[83] After the high frequency alternating current induced in the secondary coil 300 is converted into a direct current by the rectifying unit 311, the direct current is applied to the battery cell 400 through the voltage supply unit 312 and the current supply unit 321. Then, the battery cell 400 is charged little by little, and thus voltage of both ends of the battery cell 400 is increased to a state of full charge.

[84] Meanwhile, when the high frequency alternating current applied to the primary coil

200 is paused, induction of the high frequency alternating current in the second coil 300 is paused, consequently charging is temporarily paused. Then, the charging pause detecting unit 360 detects a point of time when the induction of the high frequency alternating current is paused, and inputs the point of time into the wireless sending unit 340. This operation is repeated every point of time when the induction of the high frequency alternating current is temporarily paused.

[85] During the above-mentioned charging of the battery cell 400, the measured current value detected by the current detecting unit 330 is transmitted wirelessly to the charger (C) at a point of time when the induction of the high frequency alternating current is paused. And, the wireless receiving unit 230 of the charger (C) receives and modulates the current value transmitted through the primary antenna 220 and inputs the current value into the microprocessor 240. Then, the microprocessor 240 controls the high frequency power driving unit 210 to calculate an amount of charging voltage supplied by the voltage supply unit 310 and adjust power of the high frequency alternating current applied to the primary coil 200 to a preset level.

[86] The above-mentioned feedback control allows for the charging voltage (V ) supplied by the voltage supply unit 310 to be supplied actively depending on the voltage (V )

2 charged to the battery cell 400, thereby minimizing the loss of power supplied for charging the battery cell 400.

[87] In the above-mentioned embodiment of the present invention, to minimize the loss of power supplied for charging the battery cell 400 of the contactless rechargeable battery (B), the current detecting unit 330 detects the current applied to the battery cell 400 and transmits a value of the detected current to the charger (C). And, the microprocessor 240 calculates an amount of the charging voltage supplied by the voltage supply unit 310 using the measured current value, and adjusts power of the high frequency alternating current applied to the primary coil 200 to a preset level.

[88] ϊfowever, the present invention may have alternative embodiments. Specifically, the contactless battery (B) further includes a microprocessor (not shown), and the microprocessor (not shown) calculates an amount of the charging voltage supplied by the voltage supply unit 310 using the measured current value, generates an adjustment request signal for adjusting power of the high frequency alternating current applied to the primary ooil 200 to a preset level and transmits wirelessly the adjustment request signal to the oontactless charger (C). Then, the microprocessor 240 controls the operation of the high frequency power driving unit 210 based on the adjustment request signal.

[89] As a result, the charging voltage (V ) supplied by the voltage supply unit 310 can be supplied actively depending on the change of voltage (V ) charged to the battery cell 400.

[90] Hereinabove, preferred embodiments of the present invention has been described in detail with reference to the accompanying drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. Industrial Applicability

[91] According to the present invention, during charging a oontactless rechargeable battery, even though overcharge is applied to both ends of a constant voltage/constant current supply unit, a charging power can be adjusted in real time by a wireless feedback control.

[92] And, a charging voltage supplied for charging the battery can be supplied actively depending on the change of voltage charged to a battery cell, thereby preventing unne cessary supply of the charging voltage.

Claims

[1] A contactless rechargeable battery having an embedded charging circuit for charging a battery cell with an electrical energy, comprising: a high frequency alternating current inducing unit, in which a high frequency alternating current is induced by a magnetic field generated in an external oontactless charger; a charging voltage supply unit for supplying voltage necessary to charge the battery cell; a charging current supply unit for supplying the battery cell with a charging current using the voltage applied from the charging voltage supply unit; and a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit, and transmitting the monitoring results to the external contactless charger through a wireless communication to induce change of intensity of the magnetic field.

[2] The oontactless rechargeable battery according to claim 1 , wherein the high frequency alternating current inducing unit is a coil, with which a magnetic flux of the magnetic field generated from the external contactless charger links.

[3] The oontactless rechargeable battery axording to claim 1, wherein the charging current monitoring unit includes: a wireless sending unit for wirelessly propagating the monitoring results through an antenna; and a current detecting unit for measuring the current supplied to the battery cell by the charging current supply unit.

[4] The oontactless rechargeable battery axording to claim 1, wherein the charging current monitoring unit further includes: a microprocessor for generating and outputting an adjustment request signal for requesting the oontactless charger to change the intensity of the magnetic field.

[5] The oontactless rechargeable battery axording to claim 4, wherein the magnetic field generated in the contactless charger is generated dis- oontiniDusly, wherein the charging current monitoring unit further includes a charging pause detecting unit for receiving the high frequency alternating current outputted from the high frequency alternating current inducing unit, detecting a point of time when the induction of the high frequency alternating current is terminated, and outputting the point of time to the microprocessor, and wherein the monitoring results are transmitted to the external contactless charger through the wireless communication while the induction of the high frequency alternating current is not made after the point of time is inputted.

[6] The contactless rechargeable battery according to claim 1, further comprising: an allowable current setting unit for setting a maximum value of the charging current supplied by the charging current supply unit.

[7] The contactless rechargeable battery according to claim 6, wherein the allowable current setting unit sets the maximum value of the charging current in consideration of a charging current necessary when charging the battery cell with the charging current of the charging current supply unit.

[8] The contactless rechargeable battery according to any one of claims 1 to 7, wherein the charging current supply unit is a transistor.

[9] A cont£ctless charging set, comprising: a contactless rechargeable battery including: a high frequency alternating current inducing unit, in which a high frequency alternating current is induced by a magnetic field generated in an external contactless charger, a charging voltage supply unit for supplying voltage necessary to charge a battery cell, a charging current supply unit for supplying the battery cell with a charging current using the voltage applied from the charging voltage supply unit, and a charging current monitoring unit for monitoring a value of the current supplied by the charging current supply unit, and transmitting the monitoring results to the external contactless charger through a wireless communication to induce change of intensity of the magnetic field; and a contactless charger including: a magnetic field generating unit for receiving a high frequency alternating current to form a magnetic field in an external space, a high frequency power driving unit for applying discontinujusly the high frequency alternating current to the magnetic field generating unit, and a charging power adjusting unit for receiving the monitoring results through a wireless communication while the high frequency alternating current is not applied to the magnetic field generating unit, and controlling the high frequency power driving unit to adjust power of the high frequency alternating current applied to the magnetic field generating unit to adjust a charging power transmitted to the battery.

[10] The contactless charging set according to claim 9, wherein the high frequency alternating current inducing unit is a coil, with which a magnetic flux of the magnetic field generated from the external contactless charger links.

[11] The contactless charging set according to claim 9, wherein the charging current monitoring unit includes: a wireless sending unit for wirelessly propagating the monitoring results through an antenna; and a current detecting unit for measuring the current supplied to the battery cell by the charging current supply unit.

[12] The contactless charging set according to claim 11, wherein the charging current monitoring unit further includes: a microprocessor for generating and outputting an adjustment request signal for requesting the contactless charger to change the intensity of the magnetic field.

[13] The contactless charging set according to claim 9, wherein the magnetic field generated in the contactless charger is generated dis- continu)usly, wherein the charging current monitoring unit further includes a charging pause detecting unit for receiving the high frequency alternating current outputted from the high frequency alternating current inducing unit, detecting a point of time when the induction of the high frequency alternating current is terminated, and outputting the point of time to the microprocessor, and wherein the monitoring results are transmitted to the external contactless charger through the wireless communication while the induction of the high frequency alternating current is not made after the point of time is inputted.

[14] The contactless charging set according to claim 9, wherein the magnetic field generating unit is a coil, to which the high frequency alternating current is applied at both ends thereof.

[15] The contactless charging set according to claim 9, wherein the charging power adjusting unit includes: a wireless receiving unit for receiving the monitoring results through an antenna; and a microprocessor for receiving the monitoring results from the wireless receiving unit and controlling the high frequency power driving unit to adjust power of the high frequency alternating current applied to the magnetic field generating unit.

[16] The Gont∑ctless charging set acoording to claim 9, wherein the oontactless charger further includes: a power supply unit for receiving and converting an alternating current into a direct current and supplying the direct current to the high frequency power driving unit, wherein the high frequency power driving unit includes: a pulse signal generating unit for receiving a pulse drive signal from a microprocessor and outputting a pulse signal; and a power driving unit for receiving the pulse signal and switching rapidly the direct current supplied by the power supply unit to generate a pulse type high frequency alternating current.

[17] The cont£ctless charging set according to claim 16, wherein the power supply unit includes: an overvoltage overcurrent protecting circuit for receiving an alternating current and intercepting an overvoltage current; a rectifying unit for rectifying the alternating current passed through the overvoltage overcurrent protecting circuit and converting the rectified alternating current into a direct current; and a constant voltage supply unit for receiving the converted direct current and outputting a constant voltage current.

[18] The contEctless charging set according to claim 9, wherein the high frequency power driving unit applies discontimxmsly the high frequency alternating current to the magnetic field generating unit, and wherein the charging power adjusting unit receives the monitoring results while the high frequency alternating current is not applied to the magnetic field generating unit.

[19] The contεctless charging set according to claim 9, wherein the charging power adjusting unit performs pulse width modulation, pulse frequency modulation, pulse amplitude modulation or pulse number modulation to adjust the charging power.

[20] The contεctless charging set according to claim 9, wherein the oontactless rechargeable battery further includes: an allowable current setting unit for setting a maximum value of the charging current supplied by the charging current supply unit.

[21] The contEctless charging set according to claim 20, wherein the allowable current setting unit sets the maximum value of the charging current in consideration of a charging current necessary when charging the battery cell with the charging current of the charging current supply unit.

[22] The contεctless charging set according to claim 9, wherein the charging current supply unit is a transistor.