fig1 shows a charging device 100 for charging a rechargeable energy store 105 . to facilitate referencing , a cartesian coordinate system is specified . charging device 100 includes a coupling surface 110 which is represented with an upward displacement in the manner of an exploded drawing . energy store 105 includes a first induction coil 115 , which is connected to an electrical storage device 125 with the aid of a control device 120 . first induction coil 115 preferably includes an electrical conductor which is wound multiple times in a circular shape . the first induction coil provides control device 120 with an electrical alternating current as a function of an alternating magnetic field 130 flowing through first induction coil 115 . control device 120 converts the alternating current into a direct current and controls it in such a way that electrical storage device 125 may be recharged therefrom . storage device 125 may be a capacitor , in particular a double layer capacitor , or an accumulator , in particular a nickel metal hydride or lithium ion accumulator . coupling surface 110 is represented as a flat rectangle , although coupling surface 110 may also have a different shape , in particular a curved shape in other specific embodiments . coupling surface 110 is also not limited to being situated largely perpendicularly to the force of gravity . charging unit 100 includes a second induction coil 135 , which is mounted on a first carrier 140 which is movable in the y direction with respect to a first rail 145 . first rail 145 is mounted on a second carrier 150 , which is movable along a second rail 155 in the x direction . by correspondingly moving first carrier 140 and second carrier 150 , second induction coil 135 is fully movable on the x - y plane parallel to contact surface 110 . in another specific embodiment , second induction coil 135 may also be moved in a way other than with the aid of carriers 140 and 150 , for example with the aid of a moving device having a polar orientation . second induction coil 135 is mounted on first carrier 140 with the aid of one or multiple alignment elements 165 , alignment elements 165 permitting the second induction coil to pivot around the y axis and around the x axis . the movements of alignment elements 165 of first carrier 140 and second carrier 150 may be controlled with the aid of a control device 160 , which is connected to the corresponding moving elements . control device 160 is furthermore configured to control second induction coil 135 in such a way that it generates magnetic field 130 in the area of coupling surface 110 . the position and alignment of the magnetic field in relation to coupling surface 110 and , if necessary , also the strength of magnetic field 130 may thus be changed with the aid of control device 160 . control device 160 is configured to move second induction coil 135 in such a way that the position and alignment of second induction coil 135 are optimized in the sense of an optimized magnetic coupling between first induction coil 115 and second induction coil 135 . for this purpose , induction coils 115 , 135 must be situated in such a way that they are located as close to each other as possible , while magnetic field 130 of second induction coil 135 flows perpendicularly through first induction coil 115 . fig2 shows a direction control system 200 for charging device 100 from fig1 . direction control system 200 represents an alternative means of attaching second induction coil 135 to first carrier 140 in the specific embodiment of charging device 100 illustrated in fig1 . an additionally drawn coordinate system corresponds to the one in fig1 . direction control system 200 includes a platform 205 for attachment to first carrier 140 . platform 205 includes an upper section 210 and a lower section 215 , lower section 215 being configured for attachment to first carrier 140 , while upper section 210 supports second induction coil 135 . upper section 210 is designed to be rotatable around the z axis in relation to lower section 215 , with the aid of a first drive device 220 . second induction coil 135 is attached to upper section 210 of platform 205 with the aid of a second drive device 225 in such a way that second induction coil 135 is pivotable around an axis which runs parallel to the x - y plane and corresponds to the x axis in the representation in fig2 . if upper section 210 is rotated around the z axis in relation to lower section 215 of the platform , the axis around which second induction coil 135 is pivotable is also rotated . an azimuth ( direction angle ) may thus be changed with the aid of first drive device 220 , and an elevation ( height angle ) of second induction coil 135 may be changed with the aid of second drive device 225 . the alignment of second induction coil 135 in relation to the x - y plane is thus freely adjustable . the alignment of a magnetic field generated with the aid of second induction coil 135 also changes with the alignment of the second induction coil . fig3 shows another direction control system 300 for charging device 100 from fig1 . as with charging device 200 from fig2 , charging device 300 from fig3 is configured to provide an alternative attachment of second induction coil 235 to first carrier 140 of charging device 100 from fig1 and to simultaneously permit a change in the alignment of magnetic field 130 which may be generated by second induction coil 135 . a specified cartesian coordinate system corresponds to the coordinate systems in fig1 and 2 . direction control system 300 includes a platform 305 similar to platform 205 , platform 305 , however , having a rigid design . subcoils 310 through 320 , whose alignments differ from each other , are situated on the upper side of platform 305 . in the illustrated specific embodiment , the three subcoils 310 through 320 are inclined toward each other in such a way that axes , each of which runs perpendicularly through individual subcoils 310 through 320 , intersect above platform 305 at a point on the z axis . in other specific embodiments , subcoils 310 through 320 may also have other relative alignments or arrangements . each of subcoils 310 through 320 is configured to generate a magnetic subfield , the generated subfields being superimposed on each other to form magnetic field 130 in the area of coupling surface 110 , which is not illustrated , above platform 305 . depending on the relative alignment of subcoils 310 through 320 and the relative strengths of the generated magnetic subfields , magnetic field 130 runs in a predetermined alignment in relation to the x - y plane in the area of coupling surface 110 . fig4 shows a flow chart of a method 400 for controlling charging device 110 from fig1 . a first electrical power , which is transmittable between induction coils 115 and 135 , is determined in a first step 405 . this may be done by control device 160 providing an alternating voltage to second induction coil 135 , which subsequently generates an alternating magnetic field 130 in the area of coupling surface 110 , so that alternating field 130 may be absorbed by first induction coil 115 and converted back into an electrical current . a current intensity resulting from second induction coil 165 provides an indication of the first transmittable power . a changed alignment and / or a changed position of second induction coil 135 is / are determined in a subsequent step 410 . the determined alignment and / or position is / are implemented in a subsequent step 415 by controlling carriers 140 and 150 or drive devices 220 , 225 or subcoils 310 through 320 . in a subsequent step 420 , a second transmittable power between induction coils 115 and 135 is determined similarly to step 405 . the first determined power is compared with the second determined power in a step 425 . if the first power is less than the second power by a predetermined amount , method 400 continues with a step 430 , otherwise it continues with a step 435 . the amount may be predetermined for the purpose of influencing a sensitivity of method 400 . the amount may be set to zero for a maximum sensitivity and thus a maximum optimization of the position of second induction coil 135 and the alignment of its magnetic field 130 in relation to first induction coil 115 in each case . in step 430 , the first power determined in step 405 is set to the value of the second power determined in step 420 . this step is carried out if the changed alignment and / or position in steps 410 and 415 has / have produced an increase in the transmittable power . the method may subsequently continue with step 410 to bring about a further improvement in the transmittable power . step 435 is carried out if the change in the alignment and / or position in steps 410 and 415 have produced a decrease in the transmittable power . in this case , the changed alignment and / or position is / are reversed , and method 400 continues with step 410 for the purpose of increasing the transmittable power by another change in steps 415 and 420 .