Patent Publication Number: US-2015086317-A1

Title: Stacking system

Description:
TECHNICAL FIELD 
     The present invention relates to a system that stacks positive electrode sheets, negative electrode sheets, separators, and the like. 
     BACKGROUND ART 
     Japanese Laid-Open Patent Publication No. 2010-201593 discloses a workpiece conveying method that prevents the efficiency of work at a work station provided in the periphery of a turntable from falling, even when timing is synchronized with following processes. The workpiece conveying apparatus in this document includes a turntable that sends workpieces to a plurality of work stations disposed in the periphery of the turntable, a loading means that loads workpieces onto the turntable, an unloading means that unloads the workpieces from the turntable, and a control means that controls the loading means to intermittently load workpieces at a workpiece loading intended positions that are disposed in the circumferential direction on the turntable and controls the unloading means to unload in the order of the loaded workpieces. 
     DISCLOSURE OF THE INVENTION 
     The electrode structure used in a lithium cell or the like is manufactured by stacking (laminating) a plurality of positive electrode sheets (positive electrode plates) and negative electrode sheets (negative electrode plates) with separators in between. There is demand for an apparatus capable of stacking (laminating) separators, positive electrode sheets, and negative electrode sheets precisely and at high speed. 
     One aspect of the present invention is a stacking system including: a first turntable that is equipped with a plurality of stacking regions and rotationally moves the plurality of stacking regions to a plurality of work positions in order; and a plurality of conveying apparatuses that stake (laminate), at stacking positions included in the plurality of work positions, target objects at the stacking regions of the first turntable that have arrived at the stacking positions. Each conveying apparatus out of the plurality of conveying apparatuses includes: a first arm that rotates between a stacking position and a first preparation unit that prepares a target object to be stacked at the stacking position, picks up the target object from the first preparation unit, and stacks the target object at the stacking position; and a second arm that rotates together with the first arm between the stacking position and a second preparation unit, picks up the same target object as the first preparation unit that has been prepared at the second preparation unit, and stacks the same target object at the first position. 
     That is, the present stacking system (laminating system) rotationally moves the first turntable equipped with the plurality of stacking regions intermittently and moves the stacking regions synchronously so that the plurality of stacking regions reach the plurality of work positions in order. At each stacking position, the conveying apparatuses respectively stack each target object on each stacking region of the first turntable that has arrived at each stacking position. A stacking apparatus includes a first arm that rotates between a first stacking position and a first preparation unit that prepares a first target object to be stacked at the first stacking position, picks up the first target object from the first preparation unit, and stacks the first target object at the first stacking position and a second arm that rotates together with the first arm between the first stacking position and a second preparation unit, picks up a first target object that has been prepared at the second preparation unit, and stacks the first target object at the first position. 
     With this stacking system, when assembling an object, for example, an electrode structure, that is laminated at the respective stacking regions, the respective conveying units are capable of picking up one of an electrode sheet (a negative electrode sheet or a positive electrode sheet) and a separator alternately from the first and second preparation units and conveying to the stacking regions. Accordingly, it is possible to hide (steal) the time (takt time) taken to prepare the target objects at the first and second preparation units in the time actually taken to laminate the target objects at the stacking regions. That is, it is possible to provide double the takt time as the processing time required for preparation of the target objects. In other words, it is possible to stack the target objects at the stacking regions in half of the processing time required for preparation of the target objects. This means that it is possible to increase the stacking speed and to reduce the time necessary for stacking. As one example, it is possible to provide the time necessary for cutting and/or arranging the postures (i.e., adjusting alignment) of the target objects to be stacked at the first preparation unit and the second preparation unit. This means that it is possible to manufacture a product (layered stack) with high precision and quality in a short time. 
     One example of a stacking system is an apparatus that manufactures an electrode assembly as a product. The plurality of driving apparatuses (rotating units) of such a stacking system include a first type of conveying apparatus, which stacks (laminates) an electrode sheet, which is one of a positive electrode and a negative electrode, and a second type of conveying apparatus that stacks (laminates) a separator. The first type of conveying apparatus includes a third arm that rotates together with the first arm between a supplying unit for the electrode sheet and the first preparation unit and a fourth arm that rotates together with the third arm between the second preparation unit and the supplying unit. It is desirable for the first preparation unit and the second preparation unit to respectively include an alignment unit for the electrode sheets. At the first and second preparation units, it is possible to carrying out adjustment of alignment of the electrode sheets without sacrificing the takt time required for stacking. 
     It is possible for the second type of conveying apparatus that stacks a separator to be equipped with cutting units that cuts separators into a predetermined size at the first preparation unit and the second preparation unit where the target objects, that is, separators are picked up, and to provide the time required to prepare sheet-like separators by cutting from a roll. 
     The first turntable may include four stacking positions and one unloading position. Although the four stacking positions do not need to be in the given order, it is possible to stack a positive electrode sheet, a separator, a negative electrode sheet, and a separator in order as the target objects. That is, a first type of conveying apparatus for stacking a positive electrode sheet, a second type of conveying apparatus for stacking a separator, a first type of conveying apparatus for stacking a negative electrode sheet, and a second type of conveying apparatus for stacking a separator are disposed in order along the first turntable and it is possible to stack a positive electrode sheet, a separator, a negative electrode sheet, and a separator in order at the stacking regions that have arrived at the four stacking positions. A product (layered stack, electrode assembly) in which a predetermined number of positive electrode sheets, separators, and negative electrode sheets are laminated is unloaded from the unloading position. 
     Another aspect of the present invention is a method including stacking a plurality of electrode sheets with separators in between using a stacking system. The method may be a method of manufacturing an electrode structure and may be a method of manufacturing a cell including an electrode structure. The stacking system includes: a first turntable that is equipped with a plurality of stacking regions and rotationally moves the plurality of stacking regions in order to a plurality of work positions; and a plurality of conveying apparatuses that stack, at stacking positions included in the plurality of work positions, target objects at the stacking regions of the first turntable that have arrived at the stacking positions. Each conveying apparatus out of the plurality of conveying apparatuses includes: a first arm that rotates between a stacking position and a first preparation unit that prepares a target object to be stacked at the stacking position, picks up the target object from the first preparation unit, and stacks the target object at the stacking position; and a second arm that rotates together with the first arm between the stacking position and a second preparation unit, picks up the same target object as the first preparation unit that has been prepared at the second preparation unit, and stacks the target object at the first position. In addition, the plurality of conveying apparatuses include a first type of conveying apparatus that stacks an electrode sheet, which is one of a positive electrode and a negative electrode, and a second type of conveying apparatus that stacks a separator. 
     The stacking mentioned above includes the following steps.
     1. Rotating the first turntable to move to five work positions in order, the five positions including four stacking positions, where the first type of conveying apparatus and the second type of conveying apparatus are alternately disposed, and one unloading position.   2. Each of the first type of conveying apparatuses and the second type of conveying apparatuses that are alternately disposed stacking (placing) electrode sheets and separators, which have been picked up from different preparation units in each cycle out of the first preparation unit and the second preparation unit, simultaneously on the stacking regions that have arrived at the respective stacking positions.   

     The present invention also includes a conveying apparatus that conveys a first target object to a first work position. The conveying apparatus includes: a first arm that rotates between a first preparation unit that prepares the first target object and the first work position; a second arm that rotates together with the first arm between the first work position and a second preparation unit; a third arm that rotates together with the first arm between a supplying unit of the first target object and the first preparation unit; a fourth arm that rotates together with the third arm between the second preparation unit and the supplying unit; a driving unit that drives the first arm, the second arm, the third arm, and the fourth arm alternately in a first direction and a second direction; a function that conveys, during rotation in the first direction, a first target object from the first preparation unit to the first work position using the first arm, at the same time conveys a first target object from the supplying unit to the first preparation unit using the third arm, and carries out preprocessing at the second preparation unit; and a function that conveys, during rotation in the second direction, a first target object from the second preparation unit to the first work position using the second arm, at the same time conveys a first target object from the supplying unit to the second preparation unit using the fourth arm, and carries out preprocessing at the first preparation unit. The cycles required by preprocessing at the first and second preparation units can be hidden by the cycles in which the target objects are conveyed from the supplying unit to the work position, so that it is possible to supply preprocessed target objects in cycle units to the supply unit. 
     Yet another aspect of the present invention is a control method for a conveying apparatus. Such control method includes the following steps. 
     Moving the first arm, the second arm, the third arm, and the fourth arm in a first direction to convey a target object from the first preparation unit to the first work position using the first arm and at the same time to convey a target object from the supplying unit to the first preparation unit using the third arm, and also carrying out preprocessing at the second preparation unit. 
     Moving the first arm, the second arm, the third arm, and the fourth arm in a second direction to convey a target object from the second preparation unit to the first work position using the second arm and at the same time to convey a target object from the supplying unit to the second preparation unit using the fourth arm, and also carrying out preprocessing at the first preparation unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a diagram showing the overall layout of a stacking apparatus. 
         FIG. 2  is a diagram showing an enlargement of the configuration in the periphery of a turntable of the stacking apparatus. 
         FIG. 3  is a flowchart showing the operation of a first conveying apparatus. 
     
    
    
     DETAIL DESCRIPTION 
       FIG. 1  shows a stacking apparatus (stacking system, laminating system) that manufactures an electrode structure (cell) by stacking (laminating) positive electrode sheets, negative electrode sheets, and separators. The stacking apparatus  1  includes a rotating stage  10  including a turntable (first turntable)  11 , which rotationally moves five cell stacking jig units (cell stacking units, stacking regions)  15  in the counter-clockwise direction in the present embodiment in order to five work positions P 1 , P 2 , P 3 , P 4 , and P 5  at a 72° pitch, and five conveying apparatuses (conveying units, rotating units)  20 ,  30 ,  40 ,  50 , and  60 , which are disposed so as to partially overlap the turntable  11 . 
       FIG. 2  shows an enlargement of the configuration about the turntable  11 . The conveying apparatus  60  is a unit (unloading unit) that unloads a cell  100  that has been laminated on the turntable  11  from the work position P 5  that is the unloading position to a conveying table  80 , The conveying table  80  rotates with a pitch of 180° to convey the cell  100  via a conveying arm  81  to a finishing unit  90 . At the finishing unit  90 , fixing is performed by wrapping the outer circumference of the cell  100 , in which the positive electrode sheets, the negative electrode sheets, and the separators have been laminated, with a separator or by sticking with tape, and by doing so, the cell  100  is placed in a state where it is possible to transport the cell on a conveyor line or in a box used for conveying to an external appliance for assembling a cell or the like. 
     The stacking system  1  further includes a chassis  3  on which the rotating stage  10 , the conveying apparatuses  20  to  60 , the conveying table  80 , the finishing unit  90 , and the like are mounted, and a control unit  200  that controls the rotating stage  10 , the conveying apparatuses  20  to  60 , the conveying table  80 , the finishing unit  90 , and the like. The control unit  200  includes hardware resources as a computer, such as memory and a CPU, and realizes predetermined functions by loading a program (program product) recorded on a recording medium such as a memory. 
     The rotating stage  10  includes an actuator  12  that drives the turntable  11  in the counter-clockwise direction with a pitch of 72°. The five cell stacking units  15  mounted on the turntable  11  respectively include a stacking table  16  that forms a region (stacking region) where positive electrode sheets  111  and negative electrode sheets  112  are successively stacked and laminated with separators  115  in between and a clamp (stopper, not shown) that temporarily holds the stacked sheets. 
     The first conveying apparatus  20  is a unit that stackes (laminates) a positive electrode sheet  111  onto a cell  100  held by the cell stacking unit  15  that has arrived at the first work position P 1  out of the cell stacking units  15  of the turntable  11 . One example of the positive electrode sheets  111  is positive electrode sheets produced by applying a positive electrode active material, including a positive electrode active substance, such as metal oxide, and a conductive material such as carbon black, to both surfaces of metal foil, such as aluminum foil, as a positive electrode collector, drying, rolling, and then cutting to an appropriate size. A lithium composite oxide, such as lithium nickel oxide, can be given as an example of the positive electrode active substance. The positive electrode sheets  111  may be other type of sheets than the sheets for use in a lithium cell. 
     The first conveying apparatus  20  includes four arms that are combined in a cross at 90°, that is, a first arm  21 , a second arm  22 , a third arm  23 , and a fourth arm  24 , and a driving unit  25  that rotates such arms  21  to  24  in synchronization in the clockwise direction and the counter-clockwise direction (in forward and reverse) by 90°. Vacuum chucking units (suction units)  29  are provided at the front ends of such arms  21  to  24  so that it is possible to suck(vacuum chuck) and convey the positive electrode sheets  111 . 
     Out of such arms  21  to  24 , by driving the first arm  21  and the second arm  22  in forward and reverse, the front ends where the vacuum chucking units  29  are provided are alternately rotated so as to overlap the cell stacking unit (stacking region)  15  that has arrived at a first work position P 1  that is the position (stacking position) where a positive electrode sheet  111  is stacked. A first preparation unit  121  and a second preparation unit  122  are disposed at positions rotated by 90° from the first work position P 1 , and the first and second arms  21  and  22  alternately move reciprocally between the first preparation unit  121  and the first work position P 1  and between the second preparation unit  122  and the first work position P 1  respectively. The first and second arms  21  and  22  convey a positive electrode sheet  111  from the preparation units  121  and  122  respectively to the first work position P 1  so as to place the positive electrode sheet  111  over the cell stacking unit  15  that has arrived at the first work position P 1 . 
     A supplying table (supplying unit)  151  for the positive electrode sheets  111  is disposed at a position that is 180° opposite the first work position P 1 . The third arm  23  and the fourth arm  24  of the first conveying apparatus  20  alternately move reciprocally (rotate) between the first preparation unit  121  and the second preparation unit  122  respectively. Accordingly, the third arm  23  and the fourth arm  24  convey positive electrode sheets  111  from the supplying table  151  alternately to the first and second preparation units  121  respectively. 
     The stacking system  1  includes a positive electrode delivery system  150  that delivers the positive electrode sheets  111  to the supplying table  151 . The positive electrode delivery system  150  includes a cutting unit  153  that cuts the positive electrode sheets  111  of a predetermined size from a roll-type positive electrode sheet  159  and a positive plate feeder  157  that supplies the roll-type positive electrode sheet  159  to the cutting unit  153 . One example of the cutting unit  153  is a unit including a double grip feeder that conveys a continuous positive electrode sheet  159  and a swing shear cutter that cuts the continuous positive electrode sheet  159  into the positive electrode sheets  111  of a predetermined size. The positive electrode sheets  111  that have been cut into the predetermined size by the cutting unit  153  are discharged to the supplying table  151 . Note that the positive electrode delivery system  150  may be a system that discharges positive electrode sheets  111  that have been cut in advance to the predetermined size from a conveying cartridge to the supplying table  151 . 
     The first and second preparation units  121  and  122  are alignment units that carry out detailed control over the orientations (angles) and positions of the positive electrode sheets  111  conveyed by the third arm  23  and the fourth arm  24  respectively. The first and second arms  21  and  22  pick up the positive electrode sheets  111  whose positions and orientations have been aligned by the first and second preparation units  121  and  122  respectively, and convey the positive electrode sheets  111  to the cell stacking units  15 , thereby stacking the positive electrode sheets  111  with predetermined orientations (angles) at predetermined positions of the cell stacking units  15 . 
     To control the postures of the positive electrode sheets  111 , the first and second preparation units  121  and  122  respectively include a camera module (not shown) that detects the XYZ directions and rotational angle θ of the positive electrode sheets  111  that have been conveyed to the preparation units and an XYZθ table  129  that adjusts the posture (i.e., performs alignment) by moving the positive electrode sheets  111  in the XYZ directions and the θ direction. The respective first and second preparation units  121  and  122  may be a type that performs alignment by guiding edges in one direction or two directions of the positive electrode sheets  111 . It is possible to control the position and orientation of a positive electrode sheet  111  by blowing out air from below to float the positive electrode sheet  111  along an inclined surface and guiding the edge of the sheet  111  with a physical guide provided at the front of the inclined surface. 
     In either method, a predetermined amount of time is consumed at the first and second preparation units  121  and  122  to control (align) the postures of the positive electrode sheets  111 . As one example, at the first preparation unit  121 , a task is repeated where a positive electrode sheet  111  that has been conveyed by the third arm  23  is received and at the end of the next cycle (a period where the first conveying apparatus  20  rotates in forward or reverse by 90°), the first arm  21  picks up the positive electrode sheet  111 . Accordingly, at the first preparation unit  121 , by aligning a received positive electrode sheet  111  between reception of such positive electrode sheet  111  conveyed by the third arm  23  (one cycle) and picking up of such positive electrode sheet  111  by the first arm  21  (the next cycle), it is possible for the first arm  21  to pick up a positive electrode sheet  111  after alignment. 
     With the conveying apparatus  20 , by passing over a positive electrode sheet  111  from the third arm  23  to the first arm  21  at the first preparation unit  121 , it is possible to provide enough time for aligning the positive electrode sheet  111  at the first preparation unit  121 . However, from the discharging of a positive electrode sheet  111  to the supplying table  151  until such positive electrode sheet  111  reaches the first work position P 1 , two cycles are required for conveying by the third arm  23  and the first arm  21 . 
     In the first conveying apparatus  20 , at different timing the fourth arm  24  conveys a positive electrode sheet  111  to the second preparation unit  122  and the second arm  22  conveys an aligned positive electrode sheet  111  from the second preparation unit  122  to the first work position P 1 . Accordingly, at the first work position P 1  that is passed by the cell stacking units  15  for laminating the positive electrode sheets  111 , aligned positive electrode sheets  111  can be supplied and stacked on the cell stacking units  15  in single cycle units. That is, in the first conveying apparatus  20 , it is possible to hide (steal) the cycles used for aligning the positive electrode sheets  111  at the first and second preparation units  121  and  122 . This means that it is possible to supply the positive electrode sheets  111  in cycle units and with no cycle delay to the cell stacking units  15 . Accordingly, it is possible to supply aligned positive electrode sheets  111  without affecting the takt time at the cell stacking units  15  and to manufacture a highly precise cell  100  in a short time. 
     In the stacking apparatus  1 , the turntable  11  is rotationally moved from the fifth work position P 5  to the first work position P 1  in synchronization with a cycle in which the first conveying apparatus  20  moves forward and in reverse by 90°. Accordingly, it is possible to place an aligned positive electrode sheet  111  on each cell stacking unit  15 . 
     The second conveying apparatus  30  is a unit that stacks (laminates) a separator  115  on the cell  100  held by the cell stacking unit  15  that has arrived at the second work position P 2  out of the cell stacking units  15  of the turntable  11 . The separators  115  prevent short circuits between the positive electrode sheets (positive electrode plates, positive electrode layers)  111  and the negative electrode sheets (negative electrode plates, negative electrode layers)  112  described above and may have a function for holding an electrolyte. One example of the separators  115  is a microporous film composed of polyolefin such as polyethylene (PE) and polypropylene (PP), and is not limited to only a single film and may be a multilayer film. The separators  115  may be structures that are not made of resin. 
     The second conveying apparatus  30  includes two arms, that is, a first arm  31  and a second arm  32 , which are combined with a pitch of 90° in an L shape and a driving unit  35  that rotates the arms  31  and  32  in synchronization in the clockwise direction and the counter-clockwise direction (i.e., in forward and reverse) by 90°. Vacuum chucking units (suction units)  29  are provided at the front ends of such arms  31  and  32  so that it is possible to vacuum chuck and convey the separators  115 . 
     When the first arm  31  and the second arm  32  rotate in forward and reverse, the front ends thereof where the vacuum chucking units  29  are provided rotate so as to alternately overlap the cell stacking unit (stacking region)  15  that has arrived at the second work position P 2  that is the position (stacking position) where the separators  115  are stacked. Also, a first preparation unit  131  and a second preparation unit  132  of the second conveying apparatus  30  are disposed at positions that are rotated by 90° from the second work position P 2 . The first and second arms  31  and  32  alternately move reciprocally between the first preparation unit  131  and the second work position P 2  and between the second preparation unit  132  and the second work position P 2 . The first and second arms  31  and  32  convey a separator  115  from the preparation units  131  and  132  respectively to the second work position P 2  to place the separator  115  over the cell stacking unit  15  that has arrived at the second work position P 2 . 
     The preparation units  131  and  132  of the second conveying apparatus  30  are both supplying tables (separator supplying tables) for the separators  115 . The stacking system  1  includes two separator delivery systems  160  that supply separators  115  respectively to the separator supplying tables  131  and  132  of the second conveying apparatus  30 . The respective separator delivery systems  160  include a cutting unit  163  that cuts the separators  115  of a predetermined size from a roll-type separator  169  and a feeder  167  that supplies the roll-type separator  169  to the cutting unit  163 . One example of the cutting unit  163  is a device including a cutter in the form of a drum in the shape of a rectangular solid, and it is possible to cut the roll-type separator  169  into a predetermined size while vacuum chucking on the respective surfaces of the drum and to supply the sheet-like separators  115  to the respective separator supplying tables  131  and  132 . Note that the separator delivery systems  160  may be systems that discharge separators  115  that have been cut in advance into a predetermined size from conveying cartridges to the supplying tables  131  and  132 . 
     In the second conveying apparatus  30 , when the arms  31  and  32  rotate in forward and reverse, a separator  115  is supplied to the cell stacking unit  15  that has arrived at the second work position P 2  at such timing (one cycle). The arms  31  and  32  pick up separators  115  in units of two cycles respectively from the respective supplying tables  131  and  132 . This means that the respective separator delivery systems  160  can use two cycles to discharge the separators  115  to the supplying tables  131  and  132 . Accordingly, at the cutting unit  163 , it is possible to use two cycles to pull out and cut the roll-type separator  169  into a predetermined size. Since the roll-type separator  169  is thin and is a material that is not very easy to handle, by consuming two cycles at the cutting unit  163 , it is possible to reliably supply separators  115  that have been cut to a highly precise size to the respective supplying tables  131  and  132 . 
     The third conveying apparatus  40  is a unit that stacks (laminates) a negative electrode sheet  112  on the cell  100  held at the cell stacking unit  15  that has arrived at the work position P 3  out of the cell stacking units  15  of the turntable  11 . One example of the negative electrode sheets  112  is a negative electrode sheet produced by applying a negative electrode active material, such as amorphous carbon, to both surfaces of metal foil, such as nickel foil or copper foil, as a negative electrode collector, drying, rolling, and then cutting to an appropriate size. 
     The third conveying apparatus  40  includes four arms that are combined in a cross at 90°, that is, a first arm  41 , a second arm  42 , a third arm  43 , and a fourth arm  44 , and a driving unit  45  that rotates such arms  41  to  44  in synchronization in the clockwise direction and the counter-clockwise direction (i.e., in forward and reverse) by 90°. Vacuum chucking units (suction units)  29  are provided at the front ends of such arms  41  to  44  so that it is possible to vacuum chuck and convey the negative electrode sheets  112 . 
     The detailed configuration of the third conveying apparatus  40  is the same as the configuration of the first conveying apparatus  20 . That is, out of the arms  41  to  44 , by driving the first arm  41  and the second arm  42  in forward and reverse, the front ends where the vacuum chucking units  29  are provided are alternately rotated so as to overlap the cell stacking unit (stacking region)  15  that has arrived at the third work position P 3  that is the position (stacking position) where the negative electrode sheets  112  are stacked. A first preparation unit  141  and a second preparation unit  142  are disposed at positions rotated by 90° from the third work position P 3 , and the first and second arms  41  and  42  alternately move reciprocally between the first preparation unit  141  and the third work position P 3  and between the second preparation unit  142  and the third work position P 3 . Accordingly, the first and second arms  41  and  42  convey a negative electrode sheet  112  from the respective preparation units  141  and  142  to the third work position P 3  so as to place the negative electrode sheet  112  over the cell stacking unit  15  that has arrived at the third work position P 3 . 
     A supplying table (supplying unit)  171  for the negative electrode sheets  112  is disposed at a position that is 180° opposite the third work position P 3 . The third arm  23  and the fourth arm  24  of the third conveying apparatus  40  alternately move reciprocally (rotate) between the first preparation unit  141  and the second preparation unit  142  respectively. Accordingly, the third arm  43  and the fourth arm  44  conveys negative electrode sheets  112  from the supplying table  171  alternately to the first and second preparation units  141  and  142 . 
     The stacking system  1  includes a negative electrode delivery system  170  that delivers the negative electrode sheets  112  to the supplying table  171 . The detailed configuration of the negative electrode delivery system  170  is the same as the positive electrode delivery system  150  and includes a cutting unit  173  that cuts the negative electrode sheets  112  of a predetermined size from a roll-type negative electrode sheet  179  and an electrode plate feeder  177  that supplies the roll-type positive electrode sheet  179  to the cutting unit  173 . The cutting unit  173  can be configured in the same way as the cutting unit  153  used for the positive electrode sheets. Note that the negative electrode delivery system  170  may be a system that discharges negative electrode sheets  112  that have been cut in advance to the predetermined size from a conveying cartridge to the supplying table  171 . 
     The first and second preparation units  141  and  142  for the negative electrode sheets  112  are alignment units that carry out detailed control of the orientations (angles) and positions of the negative electrode sheets  112  conveyed by the third arm  43  and the fourth arm  44 . The first and second arms  41  and  42  pick up the negative electrode sheets  112  whose positions and orientations have been arranged by the first and second preparation units  141  and  142 , and convey the negative electrode sheets  112  to the cell stacking units  15 , thereby stacking the negative electrode sheets  112  with predetermined orientations (angles) at predetermined positions of the cell stacking units  15 . 
     The configurations of the first and second preparation units  141  and  142  of the negative electrode sheets  112  are the same as the configurations of the first and second preparation units  121  and  122  of the positive electrode sheet  111 . That is, to control the postures of the negative electrode sheets  112 , the first and second preparation units  141  and  142  respectively include a camera module (not shown) that detects the XYZ directions and rotational angle θ of the negative electrode sheets  112  that have been conveyed to the preparation units and an XYZθ table  149  that adjusts the posture (i.e., performs alignment) by moving the negative electrode sheets  112  in the XYZ directions and the θ direction. The preparation units  141  and  142  may be a type that performs alignment by guiding edges in one direction or two directions of the negative electrode sheets  112 . 
     In the third conveying apparatus  40  also, a negative electrode sheet  112  is conveyed by the third arm  43  to the first preparation unit  141  and at the next timing (i.e., in the next cycle) a negative electrode sheet  112  is conveyed by the fourth arm  44  to the second preparation unit  142 . The first arm  41  conveys a negative electrode sheet  112  from the first preparation unit  141  to the cell stacking unit  15  at the third work position P 3  and in the next cycle, the second arm  42  conveys a negative electrode sheet  112  from the second preparation unit  142  to the cell stacking unit  15 . Accordingly, a negative electrode sheet  112  that has been aligned is supplied to the cell stacking unit  15  that has arrived at the third work position P 3  in one cycle and can be laminated at the cell stacking unit  15 . In the same way as the first conveying apparatus  20 , in the third conveying apparatus  40 , it is possible to hide the cycle for aligning a negative electrode sheet  112  at the first and second preparation units  141  and  142 . This means that it is possible to supply the negative electrode sheets  112  in cycle units and with no cycle delay to the cell stacking units  15 . 
     Accordingly, it is possible to supply aligned negative electrode sheets  112  without affecting the takt time at the cell stacking units  15 , and, by rotationally moving the turntable  11  to the work position P 3  in synchronization with a cycle in which the third conveying apparatus  40  rotates in forward and reverse by 90°, it is possible to place an aligned negative electrode sheet  112  on each cell stacking unit  15  that has arrived. This means that it is possible to manufacture a highly precise cell  100  in a short time. In addition, the positive electrode sheet  111  is laminated at the first work position P 1  using the conveying apparatus  20  and a negative electrode sheet  112  is laminated at a different work position P 3  using a different conveying apparatus  40  to the positive electrode sheets  111 . Accordingly, it is possible to prevent from the outset a situation where the material constructing the positive electrode sheet  111  and the material constructing the negative electrode sheet  112  adhere to one another and cause a short circuit. 
     The fourth conveying apparatus  50  is a unit that laminates a separator  115  on the cell  100  held by the cell stacking unit  15  that has arrived at the fourth work position P 4  out of the cell stacking units  15  of the turntable  11 . The configuration of the fourth conveying apparatus  50  is the same as the configuration of the second conveying apparatus  30  and includes two arms, that is, a first arm  51  and a second arm  52 , which are combined with a pitch of 90° in an L shape and a driving unit  55  that rotates the arms  51  and  52  in synchronization in the clockwise direction and the counter-clockwise direction (i.e., in forward and reverse) by 90°. Vacuum chucking units (suction units)  29  are provided at the front ends of such arms  51  and  52  so that it is possible to vacuum chuck and convey the separators  115 . 
     When the first arm  51  and the second arm  52  of the fourth conveying apparatus  50  rotate in forward and reverse, the front ends thereof where the vacuum chucking units  29  are provided rotate so as to alternately overlap the cell stacking unit (stacking region)  15  that has arrived at the fourth work position P 4  that is a position (stacking position) where the separators  115  are laminated. Accordingly, the fourth conveying apparatus  50  is capable of conveying separators  115 , which have been supplied by two separator delivery systems  160  to the first preparation unit  131  and the second preparation unit  132  at positions rotated by 90°, in single cycle units to the cell stacking unit  15  that has arrived at the fourth work position P 4 . 
     The control unit  200  carries out control, including the turntable  11 , the conveying apparatuses  20 ,  30 ,  40 , and  50 , and the unloading unit  60 . The control unit  200  includes a function  210  that controls the turntable  11 , a function  220  that controls a system of the first conveying apparatus  20 , a function  230  that controls a system of the second conveying apparatus  30 , a function  240  that controls a system of the third conveying apparatus  40 , a function  250  that controls a system of the fourth conveying apparatus  50 , and a function  260  that controls a system of the unloading unit  60 . The function  210  that controls the turntable  11  includes a function that carries out control to drive the turntable  11  using an actuator  12  in single units with a pitch of 72° so that the five cell stacking units  15  reach the respective work positions P 1 , P 2 , P 3 , P 4 , and P 5  in order. 
     The function (functional unit)  220  that controls the system of the first conveying apparatus  20  includes a function (first function)  221  that conveys a positive electrode sheet  111  as a target object from the first preparation unit  121  to the first work position P 1  using the first arm  21  and at the same time conveys a positive electrode sheet  111  from the supplying unit (supplying table)  151  to the first preparation unit  121  using the third arm  23  when rotating in the clockwise direction in the drawings (forward rotation, the first direction). The first function  221  includes a function that carries out a process (preprocessing) that aligns a positive electrode sheet  111  at the second preparation unit  122  while the arms  21  to  24  are rotating forwards. 
     The function unit  220  also includes a second function  222  that conveys a positive electrode sheet  111  from the second preparation unit  122  to the first work position P 1  using the second arm  22  and at the same time conveys the positive electrode sheet (target object)  111  from the supplying unit  151  to the second preparation unit  122  using the fourth arm  24  when rotating in the counter-clockwise direction in the drawings (reverse rotation, the second direction), and carries out a process (preprocessing) that aligns a positive electrode sheet  111  at the first preparation unit  121 . Using the first function  221  and the second function  222 , it is possible to hide the cycles required for the preprocessing (alignment) at the first and second preparation units  121  and  122  in the cycles in which positive electrode sheets  111  are conveyed from the supplying table  151  to the work position P 1  and to supply the preprocessed target objects in cycle units to the cell stacking units. 
     The function  220  that controls the system of the first conveying apparatus  20  further includes a third function  223  that rotates the arms  21  to  24  in forward and reverse in cycle units in synchronization using the driving unit  25  and, in synchronization with such operation, carries out control to convey positive electrode sheets  111  to the supplying table  151  in synchronization with such movement using the delivery system  150 . 
     The function (functional unit)  230  that controls the system of the second conveying apparatus  30  includes a function  231  that conveys a separator  115  from the first separator supplying table  131  to the second work position P 2  using the first arm  31  when rotating in the clockwise direction (forward rotation, the first direction), a function  232  that conveys a separator  115  from the second separator supplying table  132  to the second work position P 2  using the second arm  32  when rotating in the counter-clockwise direction (reverse rotation, the second direction), and a function  233  that carries out control that rotates the arms  31  and  32  in forward and reverse in cycle units in synchronization using the driving unit  35  and conveys separators  115  to the supplying tables  131  and  132  in synchronization with such movement using the respective delivery systems  160 . 
     The function (functional unit)  240  that controls the system of the third conveying apparatus  40 , in the same way as the function  220  that controls the system of the first conveying apparatus  20 , includes: a first function  241  that conveys a negative electrode sheet  112  from the first preparation unit  141  to the third work position P 3  using the first arm  41  and at the same time conveys a negative electrode sheet  112  from the supplying unit  171  to the first preparation unit  141  using the third arm  43  when rotating in the clockwise direction in the drawings, and while doing so, carries out processing (preprocessing) that aligns the negative electrode sheet  112  at the second preparation unit  142 ; and a second function  242  that conveys a negative electrode sheet  112  from the second preparation unit  142  to the third work position P 3  using the second arm  42  and at the same time conveys a negative electrode sheet  112  from the supplying unit  171  to the second preparation unit  142  using the fourth arm  44  when rotating in reverse, and also carries out alignment (preprocessing) of the negative electrode sheet  112  at the first preparation unit  141 . The function  240  also includes a third function  243  that rotates the arms  41  to  44  in forward and reverse in cycle units in synchronization using the driving unit  45  and, in synchronization with such operation, carries out control that conveys the negative electrode sheets  112  to the supplying table  171  using the delivery system  170 . 
     The function (functional unit)  250  that controls the system of the fourth conveying apparatus  50 , in the same way as the function  230  that controls the second conveying apparatus  30 , includes a function  251  that conveys a separator  115  from the first separator supplying table  131  to the fourth work position P 4  using the first arm  51  when rotating in the forward direction, a function  252  that conveys a separator  115  from the second separator supplying table  132  to the fourth work position P 4  using the second arm  52  when rotating in the counter-clockwise direction, and a function  253  that carries out control that rotates the arms  51  and  52  in forward and reverse in cycle units in synchronization using the driving unit  55  and conveys the separators  115  to the supplying tables  131  and  132  in synchronization with such movement using the respective delivery systems  160 . 
     The function  260  that controls the system of the unloading unit  60  includes a function which drives the unloading unit  60 , when the turntable  11  has been rotated a predetermined number of times in the counter-clockwise direction so that a positive electrode sheet  111 , a separator  115 , a negative electrode sheet  112 , and a separator  115  have been laminated at a cell stacking unit  15  for a predetermined number of layers by the conveying apparatuses  20  to  50 , to discharge the cell  100  that has been laminated from the fifth work position P 5  of the turntable  11  to the conveying table  80 . Accordingly, the unloading unit  60  is not necessarily driven in cycle units. 
       FIG. 2  shows the conveying state of the respective conveying apparatuses  20 ,  30 ,  40 , and  50  of the stacking system  1  by way of dot-dash lines C 1  and dot-dot-dash lines C 2 . The dot-dash lines C 1  and the dot-dot-dash lines C 2  may be interchanged for each of the conveying apparatuses. 
     The method of stacking (manufacturing) an electrode structure (electrode assembly) using the stacking system  1  includes a step C 0  that rotates the turntable  11  to move the respective cell stacking units  15  in order from the first work position P 1  to the fifth work position P 5 , and steps C 1  and C 2  where, in synchronization with the step C 0 , the first type of conveying apparatuses  20  and  40  and the second type of conveying apparatuses  40  and  40  that are alternately disposed simultaneously place the electrodes  111 ,  112  and the separators  115 , which have been picked up from different preparation units in each cycle out of the first preparation unit and the second preparation unit, on the cell stacking units  15  that have arrived at the respective stacking positions P 1  to P 4 . 
       FIG. 3  shows a method (operation) of controlling the first conveying apparatus  20 . In step  301 , the arms  21  to  24  are rotated forward (by 90°), a positive electrode sheet  111  is picked up from the first preparation unit  121  and conveyed to and stacked at the cell stacking unit  15  that has arrived at the first work position P 1 , and at the same time a positive electrode sheet  111  is picked up from the supplying table  151  and conveyed to the first preparation unit  121 . In addition, at the second preparation unit  122 , alignment is carried out for a conveyed positive electrode sheet  111 . 
     In step  302 , the arms  21  to  24  are rotated in reverse (by 90°), a positive electrode sheet  111  is picked up from the second preparation unit  122  and conveyed to and stacked at the cell stacking unit  15  that has arrived at the first work position P 1 , and at the same time a positive electrode sheet  111  is picked up from the supplying table  151  and conveyed to the second preparation unit  122 . In addition, at the first preparation unit  121 , alignment is carried out for a conveyed positive electrode sheet  111 . 
     In the procedure that laminates the cell  100 , the first conveying apparatus  20  repeats the steps  301  and  302  described above in cycle units (units of 90° rotation). By using this control method, the processing time for aligning the positive electrode sheets  111  at the first and second preparation units  121  and  122  is hidden, and it is effectively possible to convey a positive electrode sheet  111  in cycle units from the supplying table  151  to the first work position P 1 , that is, for every forward rotation and reverse rotation. Accordingly, it is possible to place an aligned positive electrode sheet  111  on a cell stacking unit  15  and to manufacture a highly precise cell  100  at high speed. This is also the same for the second conveying apparatus  30 , the third conveying apparatus  40 , and the fourth conveying apparatus  50 . 
     Note that although an example where an electrode structure (cell)  100  for a lithium ion cell is manufactured by the stacking apparatus  1  has been described above, the stacking apparatus  1  is not limited to lithium ion cells and is favorable for manufacturing any cell including a laminated type electrode structure.