Abstract:
A cell apparatus that emits and receives AC power via magnetic field resonance includes a cell interface and a circuit to generate a magnetic field when emitting the AC power and to generate an AC current when exposed to a magnetic field from an external device. The cell apparatus also includes a switch or sensor to determine whether a charging mode or a discharging mode is active. Because the cell apparatus emits and receives AC power via magnetic field resonance, it can be charged and discharge without electrical contact with another device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-170806 filed in the Japan Patent Office on Jul. 22, 2009, the entire content of which is hereby incorporated by reference. 
     BACKGROUND 
     1. Field 
     This invention relates to a cell apparatus which transmits AC (Alternating Current) power by wireless transmission to make transmission of AC power possible without contacts. 
     2. Discussion of the Background 
     A conventional secondary cell supplies DC (Direct Current) power to an electronic equipment of the portable type or the like and normally has a cylindrical shape or a square pole shape. The conventional secondary cell uses two positive and negative contacts, or terminals, to carry out charging and discharging therethrough. 
       FIG. 13  is a schematic diagram of a conventional secondary cell in a charging or discharging state. Referring to  FIG. 13 , the secondary cell  1  shown has a cylindrical shape and has a positive contact  2  on one end side of the cylinder in the direction of a center line thereof and a negative contact  3  at the other end side of the cylinder. 
     Usually, the secondary cell  1  is accommodated in a cell accommodating recess  4 A provided on a housing  4  of a charger or an electronic equipment and carries out charging or discharging. In the cell accommodating recess  4 A, for example, a leaf spring  5  made of a conductive metal material is provided such that the positive contact  2  of the secondary cell  1  is electrically coupled thereto, and, for example, a coil spring  6  made of a conductive metal material is provided such that the negative contact  3  of the secondary cell  1  is electrically connected thereto. 
     Where the housing  4  is provided on a charger, charging current Ic from a charging circuit  7  flows to the secondary cell  1  as seen in  FIG. 14A  to charge the secondary cell  1 . 
     On the other hand, where the housing  4  is provided on an electronic equipment, discharging circuit Id from the secondary cell  1  flows to a load circuit  8  of the electronic equipment as in  FIG. 14B  and power is consumed by the load circuit  8 . 
     Where such a conventional secondary cell  1  as described above is used, it exhibits such characteristics and problems as described below. 
     (1) It is necessary to connect the secondary cell and a circuit board in the inside of a charger or an electronic equipment by wire connection using a cable. 
     (2) In order to replace the cell in an electronic equipment, it is necessary to expose a cell accommodation section, and it is difficult to use an enclosed or waterproof structure for the electronic equipment. 
     (3) The contacts or terminals of the secondary cell must always be kept in a dirt-free state. 
     (4) Where the secondary cell is accommodated in an electronic equipment, it is necessary to provide a cell lid for the cell accommodating section to prevent coming off of the cell. It is to be noted that, where the secondary cell is configured integrally with a lid, such a cell lid as mentioned above is not required. However, where the secondary cell is of the type described, there is a drawback that the charger is configured for exclusive use for the cell. 
     (5) In a state wherein the secondary cell is accommodated in the cell accommodating section, since spring pressure is applied to the secondary cell in order to establish assured contact, it is not easy to take out the secondary cell. 
     (6) It is necessary to mechanically absorb the tolerance in size of the secondary cell. 
     (7) Since resiliency is required for a terminal on the cell accommodating section of a charger or an electronic equipment for accommodating a secondary cell, a useless expansion/contraction space is required for the charger or the electronic equipment. 
     (8) Since it is necessary for the terminals of the secondary cell to be exposed, it is difficult to prevent leakage of the cell liquid. 
     (9) Since the common secondary cell is accommodated in the cell accommodating section of an electronic equipment and used, one cell can drive only one electronic equipment at a time. 
     In order to solve the problems between a charger and a secondary cell described above, a contactless re-chargeable cell and a charger therefore wherein charging of a secondary cell is carried out by electromagnetic induction have been proposed in Japanese Patent Laid-Open No. 2005-117748 (hereinafter referred to as Patent Document 1). 
     According to the disclosure by Patent Document 1, the charger includes a primary coil for electromagnetic induction, and the contactless re-chargeable cell includes a secondary cell which excites induced current through an electromagnetic induction relationship to the primary coil. In the contactless re-chargeable cell, the current induced in the secondary coil is rectified into DC and a built-in secondary cell is charged with the DC. 
     When the contactless re-chargeable cell is incorporated in and used together with electronic equipment, it can be used quite similarly to a common dry cell or a common secondary cell. In particular, the contactless re-chargeable cell includes positive and negative contacts and can be used quite similarly as with a common dry cell or secondary cell by connecting the contacts to terminals of a cell accommodating section of an electronic equipment which are individually formed from a leaf spring and a coil spring. 
     The contactless re-chargeable cell of Patent Document 1 described above are improved in regard to the problems of the items (1), (5), (6) and (7) regarding the relationship between a charger and a secondary cell. However, the contactless re-chargeable cell of Patent 
     Document 1 exhibits no improvement in regard to the other problems described above because it includes positive and negative metal contacts such that, when it is used, the metal contacts are connected to terminals of the cell accommodating section of an electronic equipment which are individually formed from a leaf spring and a coil spring. 
     Therefore, it is desirable to provide a secondary cell apparatus which can solve all of the problems of the items (1) to (9) described hereinabove by carrying out not only charging but also discharging in a contactless fashion. 
     SUMMARY 
     The present advancements provide a cell apparatus which emits and receives AC power via a magnetic field resonance coupling to an external device. The cell apparatus includes a cell interface to interface with a cell and a first circuit to generate, in a discharging mode, a magnetic field to induce an AC current in the external device. The first circuit also generates, in a discharging mode, an AC current from a magnetic field received from the external device. A conversion circuit to generate, in the charging mode, a charge signal from the AC current generated in the first circuit is also included in the cell apparatus. The conversion circuit supplied the charge signal to the cell interface. The cell apparatus also includes a frequency generator to generate, in the discharging mode, an AC current from a discharge signal received from the cell interface, and to supply the AC current to the first circuit. 
     Where the external device includes a resonance element, AC based on energy transmitted to the resonance element can be rectified into DC and used as power supply current to the external device. 
     In this manner, in the cell apparatus, energy corresponding to AC power is obtained from the external device by magnetic field resonance to carry out charging of a cell connected to the cell interface, and the energy corresponding to the AC power is transmitted to the external device through discharge of the cell connected to the cell interface through magnetic field resonance. Further, the external device may be a charger or another electronic equipment. Accordingly, the cell apparatus can exchange power not only with the charger but also with the electronic equipment without any contact. Consequently, the problems of a conventional secondary cell described hereinabove, which includes contacts, can be solved. 
     With the cell apparatus, since it obtains energy from the external device by means of magnetic field resonance to carry out charging of the cell connected to the cell interface and transmits the energy to the external device via magnetic field resonance by discharge of the cell connected to the cell interface, it can exchange power not only with a charger but also with an electronic equipment. Accordingly, the problems of a conventional secondary cell which includes contacts can be solved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements denoted by like reference symbols. 
         FIG. 1  is a block diagram of an exemplary configuration of a cell apparatus according to an embodiment of the present invention; 
         FIG. 2  is a schematic diagram of a power transmission system which utilizes a magnetic field resonance phenomenon; 
         FIG. 3  is a schematic diagram of an exemplary configuration of the appearance of the cell apparatus according to an exemplary embodiment of the present invention; 
         FIG. 4A  is a schematic diagram of a charging mode of the cell apparatus according to an exemplary embodiment of the present invention; 
         FIG. 4B  is a schematic diagram of a discharging mode of the cell apparatus according to an exemplary embodiment of the present invention; 
         FIG. 5  is schematic diagram of an example of a configuration of a cell apparatus according to a second exemplary embodiment of the present invention; 
         FIG. 6  is a schematic diagram of a charge mode of the cell apparatus according to the second exemplary embodiment of the present invention; 
         FIG. 7  is a schematic diagram of a discharging mode of the cell apparatus of according to the second exemplary embodiment of the present invention; 
         FIG. 8  is a schematic diagram of an example of a configuration of a cell apparatus according to a third exemplary embodiment of the present invention; 
         FIG. 9  is a block diagram of an example of a configuration of the cell apparatus of according to the third exemplary embodiment of the present invention; 
         FIG. 10  is a flow chart of a mode changeover operation of the cell apparatus according to the third exemplary embodiment of the present invention; 
         FIG. 11  is a schematic diagram of an application form of the cell apparatus according to the exemplary embodiments of the present invention; 
         FIG. 12  is a schematic of another application form of the cell apparatus according to the exemplary embodiments of the present invention; 
         FIG. 13  is a schematic diagram of a manner of use of a conventional secondary cell upon charging and discharging; 
         FIG. 14A  is a schematic diagram of charging of a conventional secondary cell; and 
         FIG. 14B  is a schematic diagram of discharging of a conventional secondary cell. 
     
    
    
     DETAILED DESCRIPTION 
     Before cell apparatus according to several preferred embodiments of the present invention are described, a power transmission system which uses a magnetic field resonance phenomenon which is used in the embodiments of the present invention is described. 
     [Power Transmission System which Uses Coupling Based on a Magnetic Field Resonance Relationship] 
       FIG. 2  is an example of a configuration of a power transmission system which uses a magnetic field resonance phenomenon. Referring to  FIG. 2 , the power transmission system shown includes a power transmitting apparatus  10  which serves as a supplying source of power, that is, a power transmission side apparatus, and a power receiving apparatus  20  which serves as a supplying destination of the power, that is, a power reception side apparatus, provided in a one-by-one corresponding relationship. 
     The power transmitting apparatus  10  shown includes a resonance element  11 , an excitation element  12 , and a frequency signal generation section  13 . 
     The resonance element  11  is formed, for example, from an air-core coil in the form of a loop coil. Meanwhile, the excitation element  12  is formed, for example, from an air-core coil and connected at the opposite ends of the coil thereof to two output terminals of the frequency signal generation section  13 . The resonance element  11  and the excitation element  12  are configured so as to have a relationship wherein they are coupled strongly to each other by electromagnetic induction. 
     The air-core coil which composes the resonance element  11  has not only inductance but also capacitance and consequently has a self resonance frequency which depends upon the inductance and the capacitance. 
     The frequency signal generation section  13  generates a frequency signal of a frequency equal to the self resonance frequency of the resonance element  11 . The frequency signal generation section  13  is formed from a Kollwitz type oscillation circuit or a Hartley type oscillation circuit. 
     Though not shown, the power transmitting apparatus  10  receives supply of power from an AC power supply, and the frequency signal generation section  13  thereof generates a frequency signal. 
     Meanwhile, the power receiving apparatus  20  shown in  FIG. 2  includes a resonance element  21 , an excitation element  22 , a rectification circuit  23  and a load  24 . The load  24  may be a load circuit. The power receiving apparatus  20  may have a configuration of any of various electronic equipments. 
     The resonance element  21  is formed, for example, from an air-core coil in the form of a loop coil similarly to the resonance element  11 . Meanwhile, the excitation element  22  is formed, for example, from an air-core coil and connected at the opposite ends of the coil thereof individually to two input terminals of the rectification circuit  23 . The resonance element  21  and the excitation element  22  are formed so as to have a relationship wherein they are coupled strongly to each other by electromagnetic induction. 
     Further, the air-core coil which forms the resonance element  21  has not only inductance but also capacitance and has a self-resonance frequency which depends upon the inductance and the capacitance similarly to the resonance element  11 . 
     The self resonance frequencies of the resonance element  11  and the resonance element  21  are equal to each other and are represented by fo. 
     In the power transmitting apparatus  10  having such a system configuration as described above, a frequency signal of a frequency equal to the self resonance frequency fo of the resonance elements  11  and  21  is supplied from the frequency signal generation section  13  to the excitation element  12 . 
     Accordingly, AC of the frequency fo flows through the air-core coil which forms the excitation element  12 , and induced current of the same frequency fo is induced in the resonance element  11 , which is formed from an air-core coil similarly, by electromagnetic induction from the excitation element  12 . 
     In the system of  FIG. 2 , the self-resonance frequency of the air-core coil which forms the resonance element  21  of the power receiving apparatus  20  is the self resonance frequency fo and is equal to the self resonance frequency of the resonance element  11  of the power transmitting apparatus  10 . Accordingly, the resonance element  11  of the power transmitting apparatus  10  and the resonance element  21  of the power receiving apparatus  20  have a magnetic field resonance relationship to each other, and the coupling amount between them is maximum and the loss by them is minimum at the frequency fo. 
     As described above, in the system described, since the resonance element  11  of the power transmitting apparatus  10  and the resonance element  21  of the power receiving apparatus  20  have a relationship of magnetic field resonance, AC is supplied at the self resonance frequency fo from the resonance element  11  to the resonance element  21  in a contactless fashion. 
     In the power receiving apparatus  20 , induced current is induced in the excitation element  22  by electromagnetic induction by AC appearing in the resonance element  21 . The induced current induced in the excitation element  22  is rectified into DC by the rectification circuit  23 , and the DC is supplied as power supply current to the load  24 . 
     In this manner, power is transmitted by wireless transmission from the power transmitting apparatus  10  to the power receiving apparatus  20  using a magnetic field resonance phenomenon. 
     With the wireless power transmission of the resonance type, power can be transmitted over such a distance as three to four meters and besides high power can be transmitted. Therefore, the present embodiment has an advantage that it is possible to readily construct even a system which does not have a secondary cell built in the power receiving side. 
     Further, since energy is not transmitted without a resonating mechanism, there is a characteristic that little influence is had on any other electronic equipment. Also there is an advantage that, even if alignment for coupling is not very good, the transmission efficiency does not drop very much. 
     [Cell Apparatus According to the Embodiments of the Invention] 
     First Embodiment 
     &lt;Example of a Hardware Configuration&gt; 
     A cell apparatus according to an embodiment of the present invention described below can be applied as an apparatus which receives power supply from the power transmitting apparatus  10  in  FIG. 2  to charge a cell and supplies power to the power receiving apparatus  20  in  FIG. 2 . 
       FIG. 1  is an example of a configuration of the cell apparatus according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , the cell apparatus  30  includes a first circuit having resonance element  31  and an excitation element  32 , a rectification circuit  33 , a frequency signal generation section  34 , a cell  35 , a control section  36 , a slide switch  37 , and switch circuits  38  and  39 . 
     In the first circuit, the resonance element  31  is formed, for example, from an air-core coil in the form of a loop coil similarly to the resonance elements  11  and  21 . 
     The air-core coil which forms the resonance element  31  has not only inductance but also capacitance and has a self resonance frequency which depends upon the inductance and the capacitance similarly to the resonance elements  11  and  21 . 
     The self resonance frequency of the resonance element  31  is the frequency fo which is equal to the self resonance frequency of the resonance elements  11  and  21 . 
     Meanwhile, the excitation element  32  is formed, for example, from an air-core coil. The resonance element  31  and the excitation element  32  are configured so as to have a relationship wherein they are coupled strongly to each other by electromagnetic induction. The air-core coil which forms the excitation element  32  is connected at the opposite ends thereof to the switch circuit  38 . 
     The switch circuit  38  is provided to carry out changeover between a state wherein the opposite ends of the air-core coil which forms the excitation element  32  are individually connected to two input terminals of the rectification circuit  33 , that is, a C side, and another state wherein the opposite ends of the air-core coil are individually connected to two input terminals of the frequency signal generation section  34 , that is, a D side. In the circuit configuration of  FIG. 1 , the switch circuit  38  is controlled to carry out changeover by a changeover control signal from the control section  36 . 
     cell  35  is may be a secondary or rechargeable cell formed, for example, from a nickel-cadmium storage cell or a nickel-hydrogen cell. However, as one of ordinary skill would recognize, other cells may be used without departing from the scope of the present invention. The cell  35  is connected at the positive terminal thereof to a movable terminal of the switch circuit  39 . The switch circuit  39  changes over the connection object of the positive terminal of the cell  35  between the output terminal of the rectification circuit  33 , that is, a C side, and the power supply terminal of the frequency signal generation section  34 , that is, a D side. In the system shown, the switch circuit  38  is controlled for changeover by a changeover control signal from the control section  36 . 
     The slide switch  37  is provided on a housing  300  of the cell apparatus  30  of the present embodiment as seen in  FIG. 3 . In particular, referring to  FIG. 3 , the cell apparatus  30  of the present embodiment has an appearance of a cylindrical shape, and the slide switch  37  is provided for sliding movement in a direction along the center line of the cylindrical housing  300  on the cylindrical housing  300 . 
     A user can slidably move the slide switch  37  to selectively designate a charging state or charging mode and a discharging state or discharging mode for the cell apparatus  30 . The slide switch  37  outputs a signal, which represents which one of the charging state position and the discharging state position the movable element thereof is positioned, to the control section  36 . 
     Alternatively, the movable terminal of switch circuit  39  may be provided as a cell interface to connect to a cell, and cell  35  not provided. 
     The control section  36  decides based on the signal from the slide switch  37  which one of the charging state or charge mode and the discharging state or discharge mode is selectively designated by the user. 
     Then, if the control section  36  decides that the charging state or charge mode is selectively designated by the user as a result of the sliding movement of the slide switch  37 , then it controls the switch circuits  38  and  39  so as to be change over to the C side described hereinabove with reference to  FIG. 1 , that is, to the state wherein the path of the rectification circuit  33  is selected. 
     On the other hand, if the control section  36  decides that the discharging state or discharge mode is selectively designated by the user as a result of the sliding movement of the slide switch  37 , then it controls the switch circuits  38  and  39  so as to be change over to the D side described hereinabove with reference to  FIG. 1 , that is, to the state wherein the path of the frequency signal generation section  34  is selected. 
     &lt;Operation&gt; 
     Charging operation of charging the cell  35  of the cell apparatus  30  having such a configuration as described above and discharging operation of discharging from the cell  35  are described with reference to  FIGS. 4A and 4B , respectively. 
     First, the charging operation of the cell  35  is described with reference to  FIG. 4A . 
     In this instance, the power transmitting apparatus, or external device  10 , in  FIG. 2  is used as a charger. At this time, an AC plug  14  connected to the power transmitting apparatus  10  is connected to an AC plug socket as seen in  FIG. 4A  so that power is supplied to the power transmitting apparatus  10 . It is to be noted that power may be supplied to the power transmitting apparatus  10  otherwise through an AC adapter. 
     Then, the user would place the cell apparatus  30  in an opposing relationship into the power transmitting apparatus  10  so that the resonance elements  11  and  31  of them may be positioned so as to establish a magnetic field resonance relationship to each other as seen in  FIG. 4A . 
     Then, the user would slidably move the slide switch  37  to the charging state or charging mode side. Consequently, the control section  36  detects that the slide switch  37  is moved to the charging state or charging mode side and changes over the switch circuits  38  and  39  to the C side as in  FIG. 1 . 
     In this state, AC magnetic field energy is transmitted from the resonance element  11  of the power transmitting apparatus  10  to the resonance element  31  of the cell apparatus  30  by coupling between the resonance element  11  of the power transmitting apparatus  10  and the resonance element  31  of the cell apparatus  30  by a magnetic field resonance relationship to each other. 
     Then, induced current is induced in the excitation element  32  by electromagnetic induction by AC appearing in the resonance element  31 . The induced current is supplied to the rectification circuit  33  through the switch circuit  38 . The induced current is rectified into DC by the rectification circuit  33 , and the DC is supplied to the cell  35  through the switch circuit  39  to charge the cell  35 . 
     Now, discharging operation of the cell  35  is described with reference to  FIG. 4B . 
     In this instance, the power transmitting apparatus  10  shown in  FIG. 2  is used as a driven electronic equipment. 
     The user would position the cell apparatus  30  in an opposing relationship to the power receiving apparatus  20  as seen in  FIG. 4B  so that the resonance elements  21  and  31  of them may be positioned so as to establish a magnetic field resonance relationship to each other. 
     Then, the user would operate the slide switch  37  to slidably move to the discharging state or discharge mode side. Consequently, the control section  36  detects that the slide switch  37  is moved to the discharging state or discharging mode side and changes over the switch circuits  38  and  39  to the D side shown in  FIG. 1 . 
     In this state, in the cell apparatus  30 , DC from the cell  35  is supplied as power supply current to the frequency signal generation section  34  through the switch circuit  39 . Consequently, the frequency signal generation section  34  outputs a frequency signal of the resonance frequency. 
     Then, the frequency signal from the frequency signal generation section  34  is supplied to the excitation element  32  through the switch circuit  38 . 
     Accordingly, AC of the frequency fo flows through the air-core coil which forms the excitation element  32 , and induced current of the same frequency fo is induced in the resonance element  31 , which is formed from an air-core coil similarly, by electromagnetic induction. 
     The self resonance frequency of the air-core coil which forms the resonance element  21  of the power receiving apparatus  20  is the frequency fo and is equal to the self resonance frequency of the resonance element  31  of the cell apparatus  30 . Accordingly, the resonance element  31  of the cell apparatus  30  and the resonance element  21  of the power receiving apparatus  20  have a relationship of magnetic field resonance, and therefore, transmission of AC magnetic field energy is carried out between them. Consequently, AC is supplied in a contactless fashion from the resonance element  11  to the resonance element  21  at the frequency fo. 
     In the power receiving apparatus  20 , induced current is induced in the excitation element  22  by electromagnetic induction by AC appearing in the resonance element  21 . The induced current induced in the excitation element  22  is rectified into DC by the rectification circuit  23 , and the DC is supplied as power supply current to the load  24 . 
     In this manner, power is transmitted by wireless transmission from the cell apparatus  30  to the power receiving apparatus  20 , that is, to a driven electronic equipment, using a magnetic field resonance phenomenon. 
     As described above, the cell apparatus  30  of the present embodiment carries out energy exchange by wireless transmission through an AC magnetic field. Therefore, although the charger requires a power transmitting equipment and the driven electronic equipment body requires a power receiving equipment, energy exchange can be carried out in a contactless fashion between the cell apparatus  30  of the present embodiment and the charger and driven electronic equipment. 
     The cell apparatus  30  of the present embodiment fundamentally eliminates such a work for accommodating or fitting the same into the cell accommodating section of a charger or a driven electronic equipment as is required for a conventional secondary cell or the contactless re-chargeable cell of Patent Document 1. 
     Therefore, it is necessary to explicitly indicate on the cell apparatus  30  in which one of the charging state or charging mode and the discharging state or discharge mode the cell apparatus  30  is. In the embodiment described above, the slide switch  37  plays a role of the explicit indication means. 
     [Other Forms of the Cell Apparatus] 
     The explicit indication means of the charging mode and the discharging mode is not limited to such manual operation means as the slide switch in the example described above but may be configured in various manners. 
     Second Embodiment 
       FIGS. 5 to 7  show a second embodiment of the present invention wherein the cell apparatus  30  of the first embodiment described hereinabove includes a microswitch  301  which is used as explicit indication means of a charging state and a discharging state of the microswitch  301 . In other words, the second embodiment is similar to the first embodiment described hereinabove except that the microswitch  301  is used in place of the slide switch  37  used in the first embodiment. 
     In the second embodiment, the microswitch  301  is provided in the cell apparatus  30  such that an operating element  302  of an actuator section of the self-reset type thereof projects outwardly of the housing  300  of the cell apparatus  30 . In the present example, the microswitch  301  is provided in the cell apparatus  30  such that the operating element  302  can be moved along a direction of the center line of the housing  300 . 
     Further, in the present example, an accommodation section  101  for the cell apparatus  30  is provided on a housing  10 S of the power transmitting apparatus  10  which serves as a charger as seen in  FIG. 6 . A recessed portion  103  is formed on a side inner face  102  of the accommodation section  101  in an opposing relationship to the operating element  302  of the microswitch  301  when the cell apparatus  30  is accommodated in the accommodation section  101 . 
     Furthermore, in the present example, another accommodation section  201  for the cell apparatus  30  is provided in a housing  20 S of a driven electronic equipment or power receiving apparatus of an object of discharge as seen in  FIG. 7 . In this instance, such a recessed portion as is provided in the case of the charger is not provided on a side inner wall  202  of the accommodation section  201 . 
     Accordingly, in a state wherein the cell apparatus  30  is accommodated in the accommodation section  101  of the power transmitting apparatus  10  which is formed as a charger, the operating element  302  of the microswitch  301  is received in the recessed portion  103  and remains in the projecting state to the outside. In other words, the microswitch  301  is placed into a first changeover state. 
     On the other hand, if the cell apparatus  30  is accommodated into the accommodation section  201  of the housing  20 S of a driven electronic equipment or power receiving apparatus of an object of discharging, then the operating element  302  of the microswitch  301  is pressed by the side inner face  102  so that it is placed into a state wherein it is pushed in to the inside of the microswitch  301 . In other words, the microswitch  301  is placed into a second changeover state different from the first changeover state. 
     In the second embodiment, the control section  36  detects a signal corresponding to a changeover state from the microswitch  301  in  FIG. 1  in place of the slide switch  37  to decide whether an instruction of the charge mode or another instruction of the discharge mode is received. 
     Then, the control section  36  controls changeover of the switch circuits  38  and  39  in such a manner as described above in response to a result of the mode decision. In particular, when the microswitch  301  is in the first changeover state, the control section  36  changes over the switch circuits  38  and  39  to the C side of  FIG. 1  so as to select the path of the rectification circuit  33 . In other words, the cell apparatus  30  is placed into the charge mode state. 
     On the other hand, when the microswitch  301  is in the second changeover state, the control section  36  changes over the switch circuits  38  and  39  to the D side in  FIG. 1  so as to select the path of the frequency signal generation section  34 . In other words, the cell apparatus  30  is placed into the discharge mode state. 
     It is to be noted that, in the description of the second embodiment above, an accommodation section for the cell apparatus of the embodiment of the present invention is provided on a charger as a power transmitting apparatus and a driven electronic equipment as a power receiving apparatus. However, an accommodation section for the cell apparatus of the embodiment may not be provided in such apparatus as mentioned above but may assume a form of a cell accommodating adapter. 
     In particular, an accommodation section for the cell apparatus of the embodiment is provided on a cell accommodating adapter. As the accommodation section of the cell accommodating adapter, two accommodation sections including such an accommodation section for charging as seen in  FIG. 6  and such another accommodation section for discharging as seen in  FIG. 7  are provided. 
     Or, also it is possible to assume a configuration wherein only an accommodation section for the cell apparatus of the embodiment is provided on a cell accommodating adapter. In this instance, in order to establish the charge mode, the cell apparatus  30  of the embodiment is accommodated into the accommodation section as seen in  FIG. 6 . On the other hand, in order to establish the discharge mode, the cell apparatus  30  of the embodiment is accommodated into the accommodation section such that the operating element  302  side of the microswitch  301  of the cell apparatus  30  of the embodiment is opposed to a side inner wall of the accommodation section remote from the side inner wall on which the recessed portion  103  is formed in  FIG. 6 . At this time, the cell accommodating adapter preferably has an explicit indication thereon which indicates the cell apparatus can be changed over between the charge mode and the discharge mode in response to the accommodation direction of the cell apparatus  30  of the embodiment in the accommodation section. 
     It is to be noted that, while a microswitch is used in the present second embodiment, since only it is necessary to allow detection of the charge mode and the discharge mode based on the state of a movable member, the detection method is not limited to the method which uses a microswitch. 
     Third Embodiment 
     A third embodiment of the present invention is directed to the explicit indication means for the charge mode and the discharge mode of the cell apparatus  30  according to the present invention. 
     Also in the third embodiment, an accommodation section  101  for a cell apparatus  30  is provided on a housing  10 S of a power transmitting apparatus  10  serving as a charger as seen in  FIG. 8 . However, there is no necessity to provide an accommodation section for the cell apparatus  30  on a housing  20 S of a driven electronic equipment or power receiving apparatus of an object of discharging. 
     Further, in the third embodiment, for example, a permanent magnet  110  is provided on the housing  10 S as seen in  FIG. 8  while a magnetic field sensor  310  for detecting a magnetic field of the permanent magnet  110  is provided on the cell apparatus  30 . 
     An example of a hardware configuration of the cell apparatus  30  in the third embodiment is shown in a block diagram of  FIG. 9 . 
     As can be recognized from  FIG. 9 , in the present third embodiment, the cell apparatus  30  includes a magnetic field sensor  310  in place of the slide switch  37  in the first embodiment or the microswitch in the second embodiment, and a sensor output of the magnetic field sensor  310  is supplied to the control section  36 . The other part of the cell apparatus  30  has a configuration quite same as that in the first embodiment. 
     In the third embodiment, the control section  36  carries out changeover control of the switch circuits  38  and  39  in such a manner as illustrated in  FIG. 10 . In the present example, the control section  36  can be configured using a microcomputer or a microprocessor. 
     In particular, referring to  FIG. 10 , the control section  36  normally supervises a sensor output of the magnetic field sensor  310  to decide whether or not a magnetic field from the permanent magnet  110  of a charger is detected at step S 101 . 
     If the control section  36  decides at step S 101  that a magnetic field from the permanent magnet  110  is detected by the magnetic field sensor  310 , then it changes over the switch circuits  38  and  39  to the C side of  FIG. 8  to select the path of the rectification circuit  33  at step S 102 . In other words, the control section  36  places the cell apparatus  30  into the discharge mode state. Then, the processing returns from step S 102  to step S 101 . 
     On the other hand, if the control section  36  decides at step S 101  that a magnetic field from the permanent magnet  110  is not detected, then the control section  36  changes over the switch circuits  38  and  39  to the D side of  FIG. 1  to select the path of the frequency signal generation section  34  at step S 103 . In other words, the control section  36  places the cell apparatus  30  into the discharge mode state. Then, the processing returns from step S 103  to step S 101 . 
     It is to be noted that, while, in the third embodiment described above, a magnetic field sensor is used, the sensor for distinguishing the charge mode and the discharge mode from each other is not limited to a magnetic field sensor, but some other sensor such as an optical sensor can naturally be used instead. 
     [Advantages of the Cell Apparatus  30  of the Embodiments] 
     Where the cell apparatus  30  of the embodiments described above are used, the following advantages can be achieved. 
     (a) There is no necessity to use a cable to connect the cell apparatus and a circuit board in the inside of an equipment to each other. 
     (b) Since a mechanical consideration regarding accommodation of a cell is little required in design and a wire connection mechanism is not required, the degree of freedom in design of an apparatus is high. 
     (c) Since no cell accommodation section is required and a wire connection mechanism is not required, restrictions to design of an equipment are reduced. 
     (d) Since no terminal for a cell is provided, a mechanical failure can be eliminated. 
     (e) Since no terminal for a cell is required, a waterproof and dustproof mechanism can be achieved readily. 
     (f) If the cell apparatus of the embodiments are formed in an enclosed structure, then there is no possibility of leakage of the liquid. 
     (g) Since the cell apparatus of the embodiments may generally be provided in the proximity of an equipment, a lid for the cell can be eliminated. 
     (h) Since the cell apparatus of the embodiments may generally be provided in the proximity of an equipment, the cell can be removed and accommodated readily. 
     (i) Since energy exchange by wireless transmission is applied, it is possible to supply energy to a plurality of apparatus. 
     It is to be noted that the cell apparatus can be applied not only to the system which uses coupling based on a magnetic field resonance relationship described above but also to another system which utilizes electromagnetic induction or a radio wave as described hereinabove. However, with the cell apparatus of the embodiments described, since transmission of charging power and discharging power is carried out using coupling based on a magnetic field resonance relationship, there are advantages that the power transmission distance is long and that, even if alignment of a transmitter and a receiver is not carried out strictly, a high transmission efficiency can be maintained. 
     [Embodiment of an Application Form of the Cell Apparatus  30  of the Embodiments] 
     As an example which utilizes the advantages described in the items (g) and (h) above, such a form of use as illustrated in  FIG. 11  is available. In particular,  FIG. 11  shows a notebook type personal computer or a portable apparatus foldable like a notebook wherein a resonance element  401  for power reception or the like is provided at a hinge section  400  for opening and closing movement. 
     Referring to  FIG. 11 , the cell apparatus  30  of any embodiment is fitted into an intermediate portion of the hinge section  400 . In this fitted state, the resonance element  31  of the cell apparatus  30  and the resonance element  401  for power reception are placed in a state wherein they are coupled to each other by a magnetic field resonance relationship. Consequently, power can be supplied from the cell apparatus  30  to the notebook type personal computer or the portable apparatus. 
     On the other hand, as an example which utilizes the advantage described in the item (i) given hereinabove, an application as a power supply station is available. For example, if one cell apparatus  30  is placed in a bag as seen in  FIG. 12 , then supply of power to a portable telephone terminal  321 , a music player  322 , a game machine not shown and so forth in the bag can be carried out simultaneously, and there is no necessity to prepare individual battery chargers. 
     [Other Embodiments and Modifications] 
     While, in the embodiments described hereinabove, the resonance relationship between resonance elements is given by magnetic field resonance, the present invention can be applied also where magnetic field resonance is applied. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.