Abstract:
A battery ( 1 ) comprises a chargeable and dischargeable battery cell ( 23 ); a first electrode ( 21 ) and a second electrode ( 22 ) connected to the battery cell and electrically connected to an external electrode in a non-contact state; a switching circuit ( 24 ) which is provided in a battery circuit comprising the battery cell, the first electrode and the second electrode, and switches the current flowing in the battery circuit to alternating current or direct current; and an insulating housing ( 10 ) which houses the battery cell, the first electrode, the second electrode and the switching circuit therein.

Description:
[0001]    The present invention relates to a battery and a battery system. This application is a continuation application based on a PCT International Application No. PCT/JP2014/080232, filed on Nov. 14, 2014. The content of the PCT International Application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
     Description of Related Art 
       [0002]    In recent years, medical devices have been becoming wireless, and types of treatment tools in which power is supplied from a battery have started to be proposed. 
         [0003]    In that case, lithium ion batteries with high energy density per unit mass are expected to be generally utilized. 
         [0004]    A general battery includes a battery cell capable of being charged and discharged, a conductive terminal for being electrically connected to an external charger or a medical device and the like (see, for example, Japanese Patent No. 4554222). When the battery is charging or discharging, a terminal of the battery and a conductive terminal or the like provided in the charger or the like are brought into contact with each other to electrically connect the terminals together. 
       SUMMARY OF THE INVENTION 
       [0005]    According to a first aspect of the present invention, a battery comprises: a chargeable and dischargeable battery cell; a first electrode and a second electrode connected to the battery cell and electrically connected to an external electrode in a non-contact state; a switching circuit which is provided in a battery circuit comprising the battery cell, the first electrode and the second electrode, and switches the current flowing in the battery circuit to an alternating current or a direct current; and an insulating housing which houses the battery cell, the first electrode, the second electrode and the switching circuit therein. 
         [0006]    According to a second aspect of the present invention, there is provided a battery system comprising: the battery of the present invention; and a connecting device which has a recess in which the battery is loaded, and a connecting device side first electrode and a connecting device side second electrode disposed along inner surfaces of the recess therein, wherein when the battery is loaded in the recess, the first electrode and the second electrode face the connecting device side first electrode and the connecting device side second electrode to be capacitively coupled. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view showing a battery according to a first embodiment of the present invention. 
           [0008]      FIG. 2  is a cross-sectional view of the battery. 
           [0009]      FIG. 3  is a perspective view showing a battery system equipped with the battery and a charger. 
           [0010]      FIG. 4  is a schematic partial sectional view of the charger. 
           [0011]      FIG. 5  is a circuit diagram of charging. 
           [0012]      FIG. 6  is a perspective view showing a treatment tool on which the battery is mounted. 
           [0013]      FIG. 7  is a circuit diagram of discharging to the treatment tool. 
           [0014]      FIG. 8  is a cross-sectional view showing an example of a state in which the battery is loaded on the treatment tool. 
           [0015]      FIG. 9  is a cross-sectional view showing an example of a state in which the battery is loaded on the treatment tool. 
           [0016]      FIG. 10  is a perspective view showing a battery according to a second embodiment of the present invention. 
           [0017]      FIG. 11  is a cross-sectional view of the battery. 
           [0018]      FIG. 12  is a perspective view showing a modified example of the battery. 
           [0019]      FIG. 13  is a perspective view showing a modified example of the battery of the present invention. 
           [0020]      FIG. 14  is a schematic cross-sectional view showing an example of electrode arrangement in the modified example. 
           [0021]      FIG. 15  is a perspective view showing a modified example of the battery of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Hereinafter, a first embodiment of the present invention will be described with reference to  FIGS. 1 to 9 . 
         [0023]      FIG. 1  is a perspective view showing a battery  1  of the present embodiment. The battery  1  comprises an insulating housing  10  which constitutes an outer surface of the battery  1 , and a first electrode  21  and a second electrode  22  disposed inside the housing  10 . 
         [0024]    The housing  10  is formed of an insulating material. A resin is preferable as a material for forming the housing  10 . For example, polycarbonate, a fluororesin, polyether ether ketone (PEEK) and the like can be used as the material. The dielectric constant of the insulating material forming the housing  10  is preferably 2 or more. When the housing  10  is made of a high dielectric constant material with a dielectric constant of 2 or more, it is possible to increase the electrostatic capacitance generated at the time of power transmission/reception to be described later, and to lower the voltage value applied to the electrode at the time of power transmission/reception. 
         [0025]      FIG. 2  is a cross-sectional view of the battery  1 , and shows a state seen from a right side surface  13  side shown in  FIG. 1 . A battery cell  23  capable of being charged and discharged, and a switching circuit  24  are housed inside the housing  10 . The switching circuit  24  is electrically connected to the battery cell  23 , a first electrode  21  and a second electrode  22 . The first electrode  21 , the second electrode  22 , the battery cell  23  and the switching circuit  24  are connected by a wiring  25  to form a battery circuit. 
         [0026]    The switching circuit  24  has two functions. One of the functions is to switch the current flowing inside the battery circuit between AC and DC, and the other thereof is to switch whether to discharge the AC current to the outside of the battery or to charge the battery cell with the DC current. Thus, the DC current flows through the battery cell  23  side of the switching circuit  24 , the AC current flows through the first electrode  21  and the second electrode  22 , and the discharging and charging modes are switched. 
         [0027]    Even if the battery does not have a charging and discharging mode switching function, the battery can be used as, for example, a disposable battery that can only be discharged. 
         [0028]    As the battery cell  23 , any battery cell can be used as long as it can be charged and discharged, and for example, battery cells of various known structures such as a lithium ion battery cell can be appropriately selected and used. 
         [0029]    The first electrode  21  and the second electrode  22  are formed in a planar shape by a conductor material and are symmetrically disposed to extend along a front surface  11  and a back surface  12  of the housing  10 , respectively. As a material for forming the first electrode  21  and the second electrode  22 , for example, a metal foil or the like can be used. 
         [0030]    The switching circuit  24  is not particularly limited as long as it has a DC/AC conversion function, and a well-known converter circuit or the like can be appropriately selected in consideration of the size of the battery  1  and the like. 
         [0031]    With the above-described configuration, the entire outer surface of the battery  1  is covered with the insulating housing  10  such that and the conductive member such as a terminal or an electrode is not exposed at all through the outer surface. 
         [0032]    Next, the operation when the battery  1  is used will be described. The battery  1  can be used as a battery system in combination with a connecting device for transmitting and receiving power to and from the battery  1 . 
         [0033]      FIG. 3  shows a battery system  2  comprising a battery  1 , and a charger (connecting device)  100  for charging the battery  1 . The charger  100  has a recess  101  capable of housing the battery  1 , and the entire outer surface of the charger  100  comprising the recess  101  is formed to be covered with an insulating material such as a resin. 
         [0034]      FIG. 4  is a diagram schematically showing a cross section of the charger  100 . The charger  100  comprises a planar first power transmission electrode (a connecting device side first electrode)  102  and a second power transmission electrode (a connecting device side second electrode)  103 . The first power transmission electrode  102  and the second power transmission electrode  103  are disposed along the two facing surfaces among the inner surfaces of the recess  101  so as not to be exposed. 
         [0035]    To charge the battery  1 , a user loads the battery  1  into the recess  101  such that two surfaces on which the first power transmission electrode  102  and the second power transmission electrode  103  are disposed face the front surface  11  and the back surface  12  on which the first electrode  21  and the second electrode  22  are disposed. 
         [0036]      FIG. 5  is a circuit diagram showing a state in which the battery  1  is loaded in the recess  101  as described above. Since the first power transmission electrode  102  and the second power transmission electrode  103  face the first electrode  21  and the second electrode  22 , the facing electrodes are capacitively coupled (electric field coupling) in a non-contact state to form a circuit which comprises the battery  1  and the charger  100 . The thickness of the housing  10  is set in advance to enable the above-described capacitive coupling. In  FIG. 5 , reference numeral  104  denotes a power supply circuit, and reference numeral  105  denotes a power transmission circuit for adjusting the mode of a current which is transmitted from the charger  100  to the battery  1 . 
         [0037]    When a high-frequency AC current is supplied from the charger  100  in the state in which the above-described circuit is formed, power can be transmitted to the battery  1  via the capacitively coupled electrodes. By converting the AC current transmitted from the charger  100  into a DC current by the switching circuit  24 , the battery cell  23  can be charged. 
         [0038]    Since the AC current is supplied from the charger  100 , as long as the first power transmission electrode  102  and the second power transmission electrode  103  face the first electrode  21  and the second electrode  22 , a correspondence relation of individual electrodes is not a problem, and charging can be performed in any correspondence relation. That is, the first electrode  21  may be disposed to face the first power transmission electrode  102 , or may be disposed to face the second power transmission electrode  103 . 
         [0039]    As shown in  FIG. 1  or the like, the housing  10  of the battery  1  is formed in rectangular parallelepiped shape in which the front surface  11  and the back surface  12  are formed in a square shape. Since the front surface  11  and the back surface  12  are figures having rotational symmetry, the shape of the battery  1  is the same in a posture in which any one of the four surfaces other than the front surface  11  and the back surface  12  faces upward. Further, when any one of front surface  11  or back surface  12  is on the front side, its shape does not change. Therefore, when the battery  1  is loaded in the recess  101 , the first power transmission electrode  102  and the second power transmission electrode  103  necessarily face the first electrode  21  and the second electrode  22  irrespective of the direction thereof, and charging can be performed. 
         [0040]    After the battery  1  is charged, the battery is mounted on a predetermined discharging device (connecting device) and used as a power supply.  FIG. 6  shows a grasping forceps  200  which is a treatment tool comprising a rigid insertion unit  201  and a treatment unit  202  provided at a distal end portion of the insertion unit  201 , as an example of a discharging device. The target discharging device is not limited to a treatment tool, and it can be applied without particular limitation as long as it is used by being energized. 
         [0041]    A handle  203  of the grasping forceps  200  is provided with a recess  204  for housing the battery  1 . The shape of the recess  204  may be the same as that of the recess  101  of the charger  100 . The grasping forceps  200  comprises a pair of electrodes for receiving power of the first power reception electrode (the connecting device side first electrode) and the second power reception electrode (the connecting device side second electrode). Although it is not shown in  FIG. 6 , the first power reception electrode and the second power reception electrode are disposed along the two facing surfaces among the inner surfaces of the recess  204  so as not to be exposed to the outside. That is, the pair of power receiving electrodes are housed inside the grasping forceps  200 . 
         [0042]      FIG. 7  is a circuit diagram of a circuit formed when discharging from the battery  1  to the grasping forceps  200  is performed. Like charging, when the first power reception electrode  211  and the second power reception electrode  212  face the first electrode  21  and the second electrode  22 , the facing electrodes are capacitively coupled with each other. When discharging from the battery  1  is performed, the DC current extracted from the battery cell  23  is converted into an AC current by the switching circuit  24  and is transmitted to the grasping forceps  200 . In the grasping forceps  200 , the AC current supplied from the battery  1  is appropriately adjusted by the power reception circuit  205  and is supplied to the treatment unit  202  which is a load. 
         [0043]    Like charging, when the battery  1  is loaded in the recess  204 , it is possible to perform discharging to the grasping forceps  200  irrespective of the direction. 
         [0044]    That is, as shown in  FIG. 8 , the battery  1  may be loaded in the recess  204  in the same posture as shown in  FIG. 2 , or as shown in  FIG. 9 , the battery  1  may be loaded in the recess  204  in a posture vertically reversed from the posture of  FIG. 8 . Further, even when the battery  1  is loaded in the recess  204  in the posture in which the front surface  11  and the back surface  12  are reversed from the posture shown in  FIGS. 8 and 9 , it is possible to perform discharging from the battery  1  to the grasping forceps  200 . 
         [0045]    When a high-frequency current is used in the discharging device to be applied, the supplied AC current may be used as it is by adjusting the voltage or the current value or the like by the power reception circuit  205 . When the DC current is used in the discharging device, a converter circuit or the like may be appropriately provided in the power reception circuit  205  so that the supplied AC current can be converted into the DC current. 
         [0046]    As described above, the battery  1  according to the present embodiment can be electrically connected to a connecting device such as a charger or a medical device, without using a conductive terminal such as a metal. Therefore, it is possible to receive and transmit power from and to the connecting device, while providing a configuration in which the entire outer surface is covered with the insulating housing  10 , and it can be suitably used as a battery. Unlike a normal battery, both of the input to the battery  1  and the output from the battery  1  are AC. The frequency of the AC is preferably the frequency of a high frequency band of about 100 kHz to 1 GHz. 
         [0047]    Further, since the battery  1  has no portion which is formed of a conductor such as a terminal that is exposed through the outer surface and is connected with the internal mechanism by a conductor such as wiring, for example, there is no need to take care to prevent the terminal from becoming wet and it is easy to handle. 
         [0048]    Furthermore, since there is no need to bring the connecting device into contact with terminals and the like in order to transmit and receive power, a freedom of loading to the connecting device can be set to a higher degree. 
         [0049]    In the present invention, in a battery system comprising a battery and at least one connecting device, among the postures in which the battery can be loaded in the recess of the connecting device, a posture in which the first electrode and the second electrode of the loaded battery face the connecting device side first electrode and the connecting device side second electrode provided in the connecting device to enable the capacitive coupling is defined as a ‘power transmittable and receivable posture.’ As described above, in the battery system  2 , all postures in which the battery can be loaded in the recess of the connecting device are power transmittable and receivable postures, and there are a total of eight power transmittable and receivable postures. 
         [0050]    Since an ordinary battery cannot perform the power transmission and reception unless the connecting device is brought into contact with the terminal or the like, there is basically only one posture in which power can be transmitted to and received from a single connecting device. In the battery system of the present invention, by suitably changing the external shape of the battery  1  substantially determined by the shape of the housing  10 , the shape of the recess of the connecting device, the arrangement of the first electrode  21  and the second electrode  22 , and the arrangement of the electrodes of the connecting device, it is possible to set the power transmittable and receivable postures to an arbitrary number of 2 or more. 
         [0051]    Next, a second embodiment of the present invention will be described with reference to  FIGS. 10 and 11 . A battery  51  of the present embodiment is different from the aforementioned battery  1  in the manner in which the first electrode and the second electrode are arranged. In the following description, the same configurations as those already described are denoted by the same reference numerals, and a repeated explanation will not be provided. 
         [0052]    As shown in  FIG. 10 , in the battery  51 , first electrodes  21  and second electrodes  22  are disposed on each of the front surface  11  and the back surface  12 . That is, the battery  51  comprises two first electrodes  21  and two second electrodes  22 . 
         [0053]      FIG. 11  is a cross-sectional view of the battery  51 . The two first electrodes  21  and the two second electrodes  22  are connected by wiring  25  and are at the same potential (same voltage and same phase). 
         [0054]    Although it is not shown, in the connecting device connected to the battery  51 , a connecting device side first electrode and a connecting device side second electrode are also disposed along each of two surfaces facing the front surface  11  and the back surface  12  among the inner surfaces of the recess when the battery  51  is housed. 
         [0055]    Similarly to the battery  1  of the first embodiment, the battery  51  of the present embodiment is very easy to handle and can constitute a battery system having a high freedom of loading into the connecting device. 
         [0056]    Further, since the first electrodes  21  and the second electrodes  22  are provided on each of the front surface  11  and the back surface  12 , if the battery  51  moves in the recess in the front-rear direction (the direction between the front surface  11  and the back surface  12 ) while loaded on the connecting device, the distance between the facing electrodes becomes longer in one of the front surface  11  and the back surface  12 , but the distance between the facing electrodes becomes shorter in the other thereof. Therefore, the combined capacitance of the capacitor established between the battery  51  and the connecting device is hard to change, and in the circuit formed by the battery  51  and the connecting device, the capacitance stability of the capacitor is remarkably improved and the control is easy. As a result, it is possible to perform more stable charging and discharging. 
         [0057]    However, depending on the posture in which the battery  51  is loaded on the connecting device, the manner in which the connecting device side first electrode and the connecting device side second electrode are arranged and the like, the first electrodes  21  and the second electrodes  22  may face both of the connecting device side first electrode and the connecting device side second electrode. Because the power transmission and reception are not performed in such a posture, it should be noted that there are cases in which the number of power transmittable and receivable postures becomes less than that of the battery  1 . 
         [0058]    In the present embodiment, a first electrode  21  and a second electrode  22  may be provided on only one of the front surface and the back surface of the battery. In contrast, in the connecting device, the connecting device side first electrode and the connecting device side second electrode may be disposed only in one of the two surfaces facing the front surface  11  and the back surface  12  when the battery  51  is housed. 
         [0059]    When the first electrodes  21  and the second electrodes  22  are provided on a plurality of surfaces, the first electrodes or the second electrodes on each surface may be connected to each other. A battery  51 A of the modified example shown in  FIG. 12  has a square columnar external shape with a square bottom, and the first electrodes  21  and the second electrodes  22  are disposed along each of the four outer surfaces  52 ,  53 ,  54  and  55 . Since the first electrodes  21  and the second electrodes  22  on each outer surface are connected to each other, the battery  51 A has a structure in which the first electrode  21  and the second electrode  22  are disposed on the outer surface over the entire perimeter. Since the battery  51 A has such a structure, even if the battery  51 A is loaded without considering the relative positional relations with the connecting device in the direction around an axis X 1  of the square column when loaded in the recess, it can transmit or receive power to and from the connecting device. 
         [0060]    Further, if the external shape of the battery  51 A is formed in a columnar shape with a circular bottom surface, when housed in the recess of the connecting device, even if the battery  51 A is housed in the recess without considering the positional relation with the connecting device in the circumferential direction (the direction around the columnar axis), it is possible to transmit and receive power. In this case, there are innumerable power transmittable and receivable postures in the battery system. 
         [0061]    Although the respective embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and it is possible to change combinations of constituent elements or to add or delete various changes to the respective constituent elements within a scope that does not depart from the spirit of the present invention. 
         [0062]    First, the external shape of the battery is not limited to the aforementioned shape, and the battery may be formed in any way as long as the battery can be housed in the recess of the connecting device and has two or more power transmittable and receivable postures. 
         [0063]    For example, as the battery to be loaded in the charger  100  shown in  FIG. 3 , there is no restriction on the shape of the front and back surfaces of the housing as long as the battery can be loaded in the recess  101 , and the shapes and sizes of the front surface and the back surface may be different. Also, the shapes of the surfaces to be capacitively coupled may be different between the battery and the connecting device. 
         [0064]    Further, the shapes and sizes may be different between the electrode of the battery side and the electrode on the connecting device side which are capacitively coupled with each other. 
         [0065]    Furthermore, the external shape of the battery and the shape of the recess do not need to be exactly the same. Therefore, when the battery is loaded in the recess, even if a part of the battery protrudes from the recess or a space remains in the recess, as long as the electrode on the battery side and the electrode on the connecting device side face each other so that the electrodes can be capacitively coupled with each other, they function as a battery system without problems. 
         [0066]    Furthermore, the external shape of the battery is not limited to a shape in which the outer surface includes only a flat surface. Accordingly, the external shape may have the above-described columnar shape or an elliptical columnar shape in which both sides are elliptical in the axial direction or a polygonal columnar shape with rounded corners or ridges, such as the battery  61  shown in  FIG. 13 . At this time, it is not necessary to arrange the first electrode and the second electrode in parallel with a major axis or a minor axis of the elliptical surface on both sides of the elliptical column in the axial direction. For example, as schematically shown in  FIG. 14 , the first electrode and the second electrode may be disposed to face each other in a direction which is parallel with neither the minor axis XS nor the major axis XL. 
         [0067]    In the modified example shown in  FIG. 15 , the external shape of the battery  71  is a cube, and the first electrodes  21  are disposed on each of three mutually adjacent surfaces shown in  FIG. 15 . The second electrodes  22  are disposed on each of the remaining three surfaces which are not shown in  FIG. 15 , and the battery  71  has three first electrodes  21  and three second electrodes  22 . 
         [0068]    As the connecting device of the battery  71 , a device that has a cubic recess and has the connecting device side first electrode and the connecting device side second electrode disposed on a pair of facing surfaces among the recess inner surfaces is prepared. In the battery system having such a configuration, when the battery  71  is loaded in the recess, regardless of the loading postures of the battery  71 , one of the three first electrodes  21  necessarily faces one of the connecting device side first electrode and the connecting device side second electrode, and one of the three second electrodes  22  faces the other of the connecting device side first electrode and the connecting device side second electrode. Therefore, in the battery system, there are twenty-four power transmittable and receivable postures, and usability can be remarkably improved. 
         [0069]    Further, in each of the above-described embodiments, switching between charging and discharging using the switching circuit may be performed automatically, for example, by identifying a device to which the battery is connected, or may be configured such that a user designates the switching mode. In the latter case, a switch for switching the mode may be provided on the outer surface of the battery.