Abstract:
The present invention provides a wireless power transmission apparatus installable on a wall, the wireless power transmission apparatus comprising: a housing configured to allow a wireless power reception apparatus to be placed thereon; a plug, a part of which is embedded in the housing, the plug being configured to be coupled with a socket for alternating current power installed on a wall; and a transmission unit which is embedded in the housing, converts an alternating current power supplied from the plug to a direct current power, and outputs a wireless power signal to the wireless power reception apparatus.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The present invention relates to a wireless power transmission apparatus for charging an electronic device (battery) by transmitting power in a wireless scheme. 
         [0003]    Related Art 
         [0004]    In general, a rechargeable secondary battery is mounted in a portable electronic device such as a mobile communication terminal and Personal Digital Assistants (PDA) as a battery. In order to charge the battery, there is a need for a separate charging device for providing electric energy to a battery of a portable electronic device using residential commercial power. 
         [0005]    Typically, since separate contact terminals are configured outside of a charging device and outside of the battery, respectively, the charging device is electrically connected to the battery by coupling the two contact terminals with each other. However, as described above, if the contact terminal protrudes an outside, an outer appearance is bad and the contact terminal is polluted from foreign materials so that a contact state is easily deteriorated. Further, if a battery is open due to carelessness of a user and the battery is exposed to humidity, a charged energy may be easily consumed. 
         [0006]    As an alternative scheme of the contact charging scheme, there has been proposed a wireless power charging system for transferring power in a wireless scheme so that a battery is charged in such a way that a contact terminal of the charging device does not make contact with a contact terminal of the battery. 
         [0007]    The above wireless power charging system may be placed on a desk or a table to be used. Accordingly, although a body of a wireless power transmission apparatus configuring a part of a wireless power charging system is placed on a desk or the like, the wireless power transmission apparatus should be finally connected to a socket through a wire. In spite of transmission of wireless power of the wireless power transmission apparatus, it is not clean due to the wire. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a wireless power transmission apparatus installable on a wall capable of configuring an aesthetical outer appearance suitable for wireless charging by omitting a wire exposed to an outside. 
         [0009]    An embodiment of the present invention provides wireless power transmission apparatus installable on a wall, the wireless power transmission apparatus including: a housing configured to allow a wireless power reception apparatus to be placed thereon; a plug, a part of which is embedded in the housing, the plug being configured to be coupled with a socket for alternating current power installed on a wall; and a transmission unit which is embedded in the housing, converts an alternating current power supplied from the plug to a direct current power, and outputs a wireless power signal to the wireless power reception apparatus. 
         [0010]    The housing may include a receiving groove communicating with an outside, and a rotating shaft installed in the receiving groove, and the plug comprises an electrode terminal inserted into the socket for the alternating current power and a body coupled with the electrode terminal and rotatably coupled with the rotating shaft. 
         [0011]    The housing may include: an installation part in which the plug is installed; and a mount part which extends as being bent to form an obtuse angle with respect to an extending direction of the installation part. 
         [0012]    A width of the installation part may have a size where the electrode terminal protrudes to an outside despite rotation of the plug. 
         [0013]    The housing may include a mount surface on which the wireless power reception apparatus is placed, and an installation surface on which the plug is installed, and the mount surface is arranged as being inclined with respect to the installation surface. 
         [0014]    The transmission unit may include: a transmission coil arranged in parallel with the mount surface at an inner side of the mount surface and configured to output the wireless power signal; a transmission controller located between the transmission coil and the installation surface and configured to control an operation of the transmission coil; and a shielding member located between the transmission coil and the transmission controller and configured to prevent an electromagnetic wave generated from the transmission coil from being transferred to the transmission controller. 
         [0015]    The wireless power transmission apparatus may further include a support unit installed in the housing to support the wireless power reception apparatus. 
         [0016]    The support unit may include: a support plate; and a bending plate extending from the support plate as being bent. 
         [0017]    The support unit may further include an elastic member connected to the support plate to elastically pull the bending plate toward the housing. 
         [0018]    The housing may include a mounting groove communicating with an outside, and the elastic member may be provided in the mounting groove. 
         [0019]    The wireless power transmission apparatus may further include a wired communication port exposed to an outside through the housing, and connected to the direct current power. 
         [0020]    The wireless power transmission apparatus may further include a reinforcing unit configured to reinforce adhesive strength between the housing and the socket, the reinforcing unit may include: a magnet installed at one of the housing and the socket; and a metal piece installed at the housing and the socket corresponding to the magnet. 
         [0021]    The plug may include: an electrode terminal fixed and coupled with the housing and inserted into the socket for the alternating current power; and a ground terminal removably coupled with the housing and inserted into the socket for the alternating current power, wherein the housing may include an assembling part configured to removably receive the ground terminal. 
         [0022]    The ground terminal may include a body and a locking piece protruding from the body, and the assembling part may include an assembling groove and a cover configured to cover a partial edge region in a circumference direction of the assembling groove so that the locking piece inserted into the assembling groove is caught at the cover. 
         [0023]    The ground terminal may include a body and a locking piece protruding from the body, and the assembling part may include an assembling rail and a cover configured to cover an edge region of the assembling rail so that the locking piece is caught at the cover. 
         [0024]    The assembling part may include an elastic member installed in the assembling rail, and the elastic member is elastically deformed and is restored to limit retreat of the locking piece when the locking piece moves along the assembling rail. 
         [0025]    According to the wireless power transmission apparatus installable on a wall of the present invention configured as described above, an aesthetical outer appearance suitable for wireless charging can be configured by omitting a wire exposed to an outside. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a block diagram illustrating wireless charging between a transmission unit  130  of a wireless power transmission apparatus  100  and a wireless power reception apparatus  200  according to an embodiment of the present invention. 
           [0027]      FIG. 2  is a conceptually sectional view illustrating an inner structure of the wireless power transmission apparatus  100  together with the wireless power reception apparatus  200 . 
           [0028]      FIG. 3  is a conceptually sectional view illustrating a wireless power transmission apparatus  300  together with the wireless power reception apparatus  200  according to another embodiment of the present invention. 
           [0029]      FIG. 4  is a perspective view illustrating a wireless power transmission apparatus  400  together with a socket C according to another embodiment of the present invention. 
           [0030]      FIG. 5  is a perspective view illustrating a wireless power transmission apparatus  500  according to another embodiment of the present invention together with a socket C′. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0031]    Hereinafter, a wireless power transmission apparatus installable on a wall according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. Parts irrelevant to a description are omitted to clearly illustrate the present invention, and like reference numbers designate like constituent elements through the specification in different embodiments. 
         [0032]      FIG. 1  is a block diagram illustrating wireless charging between a transmission unit  130  of a wireless power transmission apparatus  100  and a wireless power reception apparatus  200  according to an embodiment of the present invention. 
         [0033]    Referring to  FIG. 1 , a wireless power charging system according to an embodiment of the present invention includes a wireless power transmission apparatus  100  of  FIG. 2  and a wireless power reception apparatus  200 . If the wireless power transmission apparatus  100  transmits a wireless power signal to the wireless power reception apparatus  200  in an electromagnetic induction scheme, the wireless power reception apparatus  200  receiving the wireless power signal charges a battery with power of the wireless power signal or supplies power to an electronic device connected to the wireless power reception apparatus  200 . 
         [0034]    Hereinafter, an associated configuration between the wireless power transmission apparatus  100 , in detail, a transmission unit  130  and the wireless power reception  200  will be described, respectively. 
         [0035]    The transmission unit  130  may further include a transmission coil  131 , a transmission controller  135 , and an AC/DC converter  141 . However, when the wireless power transmission apparatus  100  uses a battery for storing a DC current of a vehicle, the AC/DC converter  141  may not be required. 
         [0036]    First, the transmission coil  131  is a device for transmitting a wireless power signal to a reception coil  210  of the power reception apparatus  200  in an electromagnetic induction scheme. In the present embodiment, two coils, that is, a first transmission coil  132  and a second transmission coil  133  are applicable. 
         [0037]    Next, the transmission controller  135  may include an object detecting unit  136 , a central controller  137 , a switching controller  138 , a driver  139 , and a serial resonant converter  140 . 
         [0038]    The object detecting unit  136  may detects load variation of the transmission coil  131  to determine whether corresponding load variation occurs by the wireless power reception apparatus  200 . That is, the object detecting unit  136  has a function as an ID confirming unit. Further, when the transmission coil  131  includes the first transmission coil  132  and the second transmission coil  133 , the object detecting unit  136  may determine a location of the reception coil  210  of the wireless power reception apparatus  200  corresponding to one of the first transmission coil  132  and the second transmission coil  133 . Further, the object detecting unit  136  filters and processes a charging state signal transmitted from the wireless power reception apparatus  200 . For example, if an ID signal being a response signal of an ID call signal transmitted through the transmission coil  131  is received, the object detecting unit  136  filters and processes the ID signal. If a charging state signal including information on a battery cell or charging voltage is received during charging, the object detecting unit  136  filters and processes the charging state signal. 
         [0039]    The central controller  137  receives and confirms a determination result from the object detecting unit  136 , analyzes an ID signal received by the transmission coil  131 , and transmits a power signal for transmitting a wireless power signal through the transmission coil  131  to the driver  139 . When the transmission coil  131  includes the first transmission coil  132  and the second transmission coil  133 , the central controller  137  may control to operate one of the two transmission coils  132  and  133  close to a reception coil  210  according to the determination result of the object detecting unit  136 . If the charging state signal is received from the transmission coil  131 , the central controller  137  controls the driver  139  based on the received charging state signal to change the wireless power signal. 
         [0040]    The switching controller  138  controls a switching operation of a switch between the serial resonant converter  140  and the first transmission coil  132  and the second transmission coil  133 . In the present embodiment, although two transmission coils  132  and  133  are illustrated, when one transmission coil  131  is used, the switching controller  138  is not naturally required. 
         [0041]    The driver  139  controls an operation of the serial resonant converter  140  under control of the central controller  137 . 
         [0042]    The serial resonant converter  140  generates transmission power for generating a power signal to be transmitted to provide the generated transmission power to the transmission coil  131  under control of the driver  139 . In other words, if the central controller  137  transmits a power control signal for transmitting the power signal having required power to the driver  139 , the driver  139  controls an operation of the serial resonant converter  140  corresponding to the transmitted power control signal, and the serial resonant converter  140  provides transmission power corresponding to the required power under the control of the driver  139  to the transmission coil  131  so that a wireless power signal having required strength is transmitted. The serial resonant converter  140  serves to supply power for generating a first object detecting signal and a second object detecting signal through the first transmission coil  132  and the second transmission coil  133  under the control of the driver  139 , respectively. 
         [0043]    The AC/DC converter  141  is a device for converting AC power of 220V or 110V into DC power of a predetermined voltage, and an output voltage of the AC/DC converter  141  is changed under control of the central controller  137 . 
         [0044]    The wireless power reception apparatus  200  for receiving a power signal to receive power includes a reception coil  210  configured to generate induction power according to the transmitted power signal, a rectifier  220  configured to rectify induced power, a battery cell module  230  charged with the rectified power, and a reception controller  240  configured to control the reception coil  210 , the rectifier  220 , and the battery cell module  230 . 
         [0045]    The reception coil  210  is a constituent element configured to receive a wireless power signal transmitted from the transmission coil  131  of the transmission unit  130 . 
         [0046]    The rectifier  220  rectifies the wireless power received from the reception coil  210  to a DC voltage, and maintains a charging state with a charging voltage by charging start. 
         [0047]    The battery cell module  230  becomes a charging target through DC power in the rectifier  220  under control of the reception controller  240 . Meanwhile, the battery cell module  230  includes a protective circuit such as an over voltage and over current prevention circuit and a temperature sensing circuit, and further includes a charging management module configured to collect and process information including a charging state of a battery cell. 
         [0048]    The reception controller  240  is a constituent element configured to control a current of power charged in the rectifier  220  so that a suitable current flows to the battery cell module  230 . 
         [0049]    Meanwhile, three sensors may be installed in order to detect a wireless power reception signal transmitted from the wireless power reception apparatus  200  side. The three sensors may include a DC current sensor configured to measure a DC current of the driver  139 , an AC current sensor configured to measure an AC current of the transmission coil  131 , and an AC voltage sensor configured to measure an AC voltage of the transmission coil  131 . 
         [0050]    That is, if a wireless power reception signal (that is, including an ID signal and a charging state signal) from the wireless power reception apparatus  200  is received through the transmission coil  131 , a current and a voltage in the transmission coil  131  and a current in the driver  139  are changed, and a wireless power reception signal is received by detecting the change in the current and the voltage in the transmission coil  131  and the current in the driver  139 . 
         [0051]    In the present embodiment, the wireless power reception signal may be more exactly received using the three sensors. That is, only when all signals from an AC current sensor, a DC current sensor, and an AC voltage sensor are an error signal, the central controller  137  generates an error signal. When at least one of all the signals is a normal signal, the central controller  137  controls an operation based on a received normal signal. If two or more signals are normal, the central controller  137  measures power levels of the normal signals, selects the best signal (a signal with the highest power level) from the normal signals, processes the best signal to acquire a wireless reception signal, resulting in controlling the transmission of wireless power. 
         [0052]    A detailed structure of the wireless power transmission apparatus  100  will be described with reference to  FIG. 2  to  FIG. 5 . 
         [0053]      FIG. 2  is a conceptually sectional view illustrating an inner structure of the wireless power transmission apparatus  100  together with the wireless power reception apparatus  200 . 
         [0054]    Referring to  FIG. 2 , the wireless power transmission apparatus  100  includes a housing  110  and the above mentioned transmission unit  130  and a plug  150 , and may further include a support unit  170 . 
         [0055]    The housing  110  receives the transmission unit  130  and a part of the plug  150 . The housing  110  may have a shape where a sectional area of a bottom region is wider than a sectional area of a top part. Accordingly, a mount surface  116  may be inclined with respect to an installation surface  111  of the housing  110 . In this case, the wireless power reception apparatus  200  may be mounted on the mount surface  116 . 
         [0056]    The transmission coil  131  of the transmission unit  130  is provided at a lower side of the mount surface  116 . The transmission coil  131  may be inclined with respect to the installation surface  111  parallel with the mount surface  116 . A shielding member  134  is located at a rear direction of the transmission coil  131  and shields an electromagnetic wave generated from the transmission coil  131  to exert influence upon the transmission controller  135 . The transmission controller  135  may be provided between the transmission coil  131  and the installation surface  111 . The transmission controller  135  may be connected to the transmission coil  131  through a wire in the housing  110 . 
         [0057]    The plug  150  is configured to be coupled with a socket C (see  FIG. 4 ) and receives AC power from the socket C. The plug  150  may include a body  151  and an electrode terminal  156 . In this case, the body  151  may be located in the housing  110 , and the electrode terminal  156  may be located outside of the housing  110 . The electrode terminal  156  may be connected to the transmission controller  135  through a wire in the housing  110  through the body  151 . 
         [0058]    The support unit  170  is installed in the housing  110  and supports the wireless power reception apparatus  200 . The support unit  170  may include a support plate  171  and a bending plate  173 . The support plate  171  is disposed corresponding to a side of the wireless power reception apparatus  200 . The bending plate  173  extends from the support plate  171  while being bent from the support plate  171  and may be disposed corresponding to a main surface of the wireless power reception apparatus  200 . 
         [0059]    By the above configuration, the plug  150  is coupled with the socket C so that the wireless power reception apparatus  200  may be charged to be installed on a wall W while being mounted in the housing  110 . Accordingly, charging is achieved between the wireless power transmission apparatus  100  and the wireless power reception apparatus  200  in a wireless scheme, and the socket C is connected to the wireless power transmission apparatus  100  through a wire so that a complicated problem is removed. 
         [0060]    Further, the mount surface  116  is inclined with respect to the installation surface  111  so that the wireless power reception apparatus  200  mounted on the mount surface  116  may be inclined with respect to the wall W. Accordingly, the wireless power reception apparatus  200  may be close to the transmission coil  131  by gravity. 
         [0061]    Next, a wireless power transmission apparatus according to another embodiment will be described with reference to  FIG. 3 . 
         [0062]      FIG. 3  is a conceptually sectional view illustrating a wireless power transmission apparatus  300  together with the wireless power reception apparatus  200  according to another embodiment of the present invention. 
         [0063]    Referring to  FIG. 3 , an entire configuration of the wireless power transmission apparatus  300  is substantially the same as that of the wireless power transmission apparatus  100 . However, the difference of the wireless power transmission apparatus  300  from the wireless power transmission apparatus  100  is the housing  310 , the support unit  370 , and a wired communication port  380 . 
         [0064]    First, the housing  310  has a shape which is bent once. In detail, the housing  310  may be divided into an installation part  311  in which a plug  150  is installed and a mount part  316  in which a transmission unit  330  including a transmission coil  331  is installed and on which the wireless power reception apparatus  200  is placed. In this case, the mount part  316  extends in an extending direction of the installation part  311  while being bent with respect to the extending direction of the installation part  311 . An extending direction of the mount part  316  may form an obtuse angle with the extending direction of the installation part  311 . 
         [0065]    A receiving groove  312  and a rotating shaft  313  may be formed in the installation part  311 . The receiving groove  312  communicates with an outside in a side (see  FIG. 4 ) viewed to the wall W. A body  351  of a plug  350  is received in the receiving groove  312 . The rotating shaft  313  is located in the receiving groove  312  and is connected to the body  351 . Accordingly, the body  351  may be rotated based on the rotating shaft  313  in the receiving groove  312 . In this case, a width of the installation part  311  may be determined based on a protruding length of an electrode terminal  356  of a laid plug  350  (marked with a dotted line) to the outside. 
         [0066]    The mount part  316  may include a mounting groove  317 . The mounting groove  317  is formed in a free end side of the installation part  311  and may communicate with the outside through a placed surface of the wireless power reception apparatus  200 . 
         [0067]    The support unit  370  may include a support plate  371 , a bending plate  373 , and an elastic member  375 . The support plate  371  is aligned to support a side of the wireless power reception apparatus  200 . The bending plate  373  is bent at the support plate  371  and is aligned to cover a main surface of the wireless power reception apparatus  200 . The elastic member  375  is located in the mounting groove  317  to connect a bottom of the mounting groove  317  to the support plate  371 . The elastic member  375  may include a compression coil spring. 
         [0068]    The wired communication port  380  may be exposed to an outside through a side of the side of the mount part  316  of the housing  310 . The wired communication port  380  is a port directly connected to AC power which is input through a plug  350 . For example, the wired communication port  380  may include a universal serial bus (USB). 
         [0069]    By the above configuration, since the housing  310  has a shape which is bent once, the user may align the installation part  311  toward a socket C while catching the mount part  316  by a hand. In this case, since the mount part  316  and the wall W (see  FIG. 4 ) forms an acute angle, the user easily insert the plug  350  into the socket C. 
         [0070]    In addition, the plug  350  is rotated based on the rotating shaft  313 , if the plug  350  is folded, the whole size of the wireless power transmission apparatus  300  may be reduced. Accordingly, it is easy to keep and deliver the wireless power transmission apparatus  300 . When the electrode terminal  365  protrudes to an outside while folding the plug  350 , it is easily to push the electrode terminal  365  by a finger during a procedure of lifting up the plug. 
         [0071]    Finally, since the wired communication port  380  is included, when the wireless power reception apparatus  200  is put on a desk without being placed on the housing  310 , a wire for charging may be inserted into the wired communication port  380 . 
         [0072]    A wireless power transmission apparatus different from the above wireless power transmission apparatus  300  will be described with reference to  FIG. 4 . 
         [0073]      FIG. 4  is a perspective view illustrating a wireless power transmission apparatus  400  according to another embodiment of the present invention together with a socket C. 
         [0074]    Referring to  FIG. 4 , an outer appearance of the wireless power transmission apparatus  400  is similar to that of the wireless power transmission apparatus  100  which was described with reference to  FIG. 2 . However, a wired communication port  380  of the wireless power transmission apparatus  300  is further illustrated. Moreover, a reinforcing unit  490  is further included. 
         [0075]    The reinforcing unit  490  is configured to reinforce adhesive strength between the housing  410  and the socket C. In other words, an electrode terminal  456  of a plug  450  is inserted and coupled with a coupling hole H of the socket C, the reinforcing unit  490  reinforces the adhesive strength. 
         [0076]    The reinforcing unit  490  may include a magnet  491  and a metal piece  496 . 
         [0077]    The magnet  491  may be located at one side of the housing  410 , in detail, a surface on which the plug  450  is installed. The magnet  491  may be embedded in the housing  410  so that one side of the magnet  491  is exposed or is not exposed. 
         [0078]    The metal piece  496  may be installed at the socket C corresponding to the magnet  491 . The metal piece  496  may be attached in a simple scheme by an attaching means such as a double sided tape provided from a seller. 
         [0079]    The above embodiment illustrates that the magnet  491  is installed in the housing  410  and the metal piece  496  is installed at the socket C. However, the metal piece  496  may be installed in the housing  410  and the magnet  491  may be installed at the socket C. 
         [0080]    By the above configuration, coupling between the housing  410  and the socket C may be further reinforced by secondary coupling between the magnet  491  and the metal piece  496  in addition to primary coupling between the coupling hole H and the electrode terminal  456 . 
         [0081]    Accordingly, even if weights of the wireless power transmission apparatus  400  and the wireless power reception apparatus  200  are increased, the wireless power transmission apparatus  400  may be stably coupled with the socket C. 
         [0082]    Next, a wireless power transmission apparatus according to another embodiment will be described with reference to  FIG. 5 . 
         [0083]      FIG. 5  is a perspective view illustrating a wireless power transmission apparatus  500  according to another embodiment of the present invention together with a socket C′. 
         [0084]    Referring to  FIG. 5 , the wireless power transmission apparatus  500  is substantially the same as the above wireless power transmission apparatus  400 . The difference is that a ground terminal  557  and a configuration associated therewith are included instead of the reinforcing unit  490 . This is for the purpose of corresponding to a different type of a socket C′ including a ground hole H″ in addition to a coupling hole H′. 
         [0085]    First, an assembling part is formed at a surface in which an electrode terminal  556  of a plug  550  in the housing  510 . The assembling part may include an assembling hole  521  formed at one side of the electrode terminal  456  and an assembling rail  523  installed at an opposite side of the electrode terminal  456 . One or both of two types of the assembling hole  521  and the assembling rail  523  may be formed. In the former case, a pair of assembling holes  521  or assembling rails  523  may be included.  FIG. 5  illustrates the latter case. 
         [0086]    The plug  550  further includes a ground terminal  557  in addition to an electrode terminal  556  corresponding to a ground hole H″ and the above assembling part. The ground terminal  557  is located under or above the electrode terminal  556 . In this case, since a pair of electrode terminals  556  are configured, the electrode terminal  556  and the ground terminal  557  may fully form three vertexes of a triangle. 
         [0087]    The ground terminal  557  may include a body  557   a  and a locking piece  557   b . The body  557   a  may have a bar shape. The locking piece  557   b  is formed at an end of the body  557   a  and may protrude in a radial direction of the body  557   a.    
         [0088]    The assembling part may be configured by an assembling groove  521  corresponding to the ground terminal  557 . A cover  521   a  for covering a partial edge region in a circumference direction thereof may be installed in the assembling groove  521 . Accordingly, if the body  557   a  and the locking piece  557   b  are inserted into the assembling groove  521  and are then turned, the locking piece  557   b  is caught at the cover  521   a  so that the ground terminal  557  is not separated from the housing  510 . 
         [0089]    However, the ground terminal  557  and the assembling groove  521  may be attached and separated to and from each other by screw coupling. 
         [0090]    In addition, a ground terminal  557 ′ according to another embodiment may include a body  557 ′ a  and a locking piece  557 ′ b . The body  557 ′ a  has a bar shape. The locking piece  557 ′ b  protrudes to both sides of the body  557 ′ a.    
         [0091]    Corresponding to the above ground terminal  557 ′, the above assembling part may be formed by an assembling rail  523 . The assembling rail  523  extends near the electrode terminal  556  from an end of the housing  510 . The assembling rail  523  has a cross section so that a cover  523   a  covering both edges of the assembling rail  523  covers the locking piece  557 ′ a . Accordingly, the ground terminal  557 ′ is not vertically separated from the assembling rail  523 . 
         [0092]    Further, an elastic piece  525  may be installed in the assembling rail  523 . The elastic pieces  525  are installed at both sides of the assembling rail  523  and are elastically pressed toward each other. In detail, the elastic piece  523  may include a rod, an end which of is located in the assembling rail  523  and a spring configured to press the rod toward a center line of the assembling rail  523 . Accordingly, the ground terminal  557 ′ elastically deforms the elastic piece  523  when the ground terminal  557 ′ enters along the assembling rail  523  and does not retreat by a restored elastic piece  523 . 
         [0093]    By the above configuration, the wireless power transmission apparatus  500  may correspond to a socket C′ including a ground hole H″ in addition to a coupling hole H′. Furthermore, even if the ground hole H″ is located above or under the coupling hole H′, it may correspond thereto by changing a location of the ground terminal  557  or  557 ′. 
         [0094]    The wireless power transmission apparatus installable on a wall is not limited to the configuration and an operation scheme of the embodiments. The above embodiment may be variously changed by a selective combination of all or a part of the embodiments.