Patent Publication Number: US-2023150068-A1

Title: LASER NOTCING MACHINE SCRAP DRAlNAGE CONVEYOR AND SCRAP DRAlNAGE METHOD

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to a conveyor for discharging scrap of a laser notching machine and a scrap discharge method thereof. More particularly, the present disclosure relates to a conveyor for discharging scrap of a laser notching machine and a scrap discharge method thereof, the conveyor having a new configuration capable of efficiently discharging scrap resulting from forming a tab by laser notching during continuous transfer of an electrode plate. 
     BACKGROUND ART 
     A secondary battery is generally manufactured by stacking a plurality of separators between a plurality of positive and negative electrode plates. In the manufacturing process of secondary batteries, a secondary battery is manufactured using a reel electrode plate (a continuous electrode plate, hereinafter referred to as an electrode plate for convenience) wound in a roll form on one winding roll. The electrode plate is formed by coating an active material on a thin aluminum or copper foil, and has an active material coated portion and at one end thereof, an uncoated portion exposed without an active material coating. An operation such as forming a tab through notching processing is performed while winding the electrode plate wound on one unwinding roll in a roll form on the other winding roll. The secondary battery is manufactured in such a manner that a process of forming the tab (notching process) is performed while the electrode plate, which has on each surface thereof, the active material coated portion  2 A coated with the active material and at one end thereof (upper or lower end), the uncoated portion exposed without the active material coating, is transferred along a transfer line, and then a separator is interposed between the positive and negative electrode plates by winding the electrode plate with the tab formed, or the separator is interposed and stacked between the positive and negative electrode plates by cutting the electrode plate is cut into a predetermined area. In the manufacture of the secondary battery, there is a notching process (cutting process) in which a tab is formed in an uncoated portion of an electrode plate by cutting out scrap from the electrode plate using a laser notching machine. 
     Meanwhile, the remaining part resulting from forming a plurality of tabs at regular intervals in the electrode plate with a laser becomes scrap. The strip-shaped scrap is discharged to the outside. 
     As illustrated in  FIG.  1   , in a conventional scrap discharging method, a stand  110  is installed under an electrode plate  2 , and a slit  112  for a laser path and a scrap discharge hole  114  are formed in the stand  110 . A plurality of tabs  2 C are formed at regular intervals in an uncoated portion  2 B of the electrode plate  2  as a laser moves along the slit  112  for the laser path, and the scrap discharge hole  114  sucks and discharges scrap  2 S by air suction. 
     When the electrode plate  2  continuously passes along a transfer path, the uncoated portion of the electrode plate  2  is cut with the laser emitting from a laser notching machine, thereby forming the tabs  2 C at regular intervals in the electrode plate  2 . The tabs  2 C are formed at regular intervals in the uncoated portion of the electrode plate  2  by partially laser-cutting the uncoated portion and a coated portion of the electrode plate  2  while continuously transferring the electrode plate  2 . The formation of the tabs  2 C using the laser notching machine while continuously moving the electrode plate  2  is achieved by a laser cutting process (laser notching process), which will be described as follows. 
     The process of cutting the electrode plate  2  by the laser of the laser notching machine while transferring it at a constant speed is classified into an entry cutting process, a coated portion cutting process, and an exit cutting process (see  FIG.  3   ). 
     In the entry cutting process, the laser cuts a part of each of the uncoated portion  2 B and the coated portion of the electrode plate  2  while moving obliquely in the transfer direction of the electrode plate  2 . Since the electrode plate  2  moves at a constant speed and the laser cuts the electrode plate  2  while moving obliquely in the transfer direction of the electrode plate  2 , the uncoated portion  2 B of the electrode plate  2  is cut in a right angle direction at an entry portion of the electrode plate  2 . When the electrode plate  2  moves at a constant speed and the laser cuts the electrode plate  2  while moving obliquely in the transfer direction of the electrode plate  2 , the angle of the relative speed of the laser with respect to the electrode plate  2  is 90°, and thus the uncoated portion  2 B of the electrode plate  2  is cut at a right angle at the entry portion (see  FIG.  4   ). 
     In the coated portion cutting process, the electrode plate  2  moves at a constant speed and the laser cuts a part of the coated portion while moving in the opposite direction to the moving direction of the electrode plate  2 . The electrode plate  2  and the part of the coated portion are cut in the longitudinal direction of the electrode plate  2  (i.e., the moving direction of the electrode plate  2 ) (see  FIG.  5   ). 
     In the exit cutting process, the laser cut a part of each of the uncoated portion  2 B and the coated portion of the electrode plate  2  while moving obliquely in the opposite direction to the transfer direction of the electrode plate  2 . Since the electrode plate  2  moves at a constant speed and the laser cuts the electrode plate  2  while moving obliquely in the opposite direction to the transfer direction of the electrode plate  2 , the uncoated portion  2 B of the electrode plate  2  is cut in a right angle direction at an exit portion of the electrode plate  2 . When the electrode plate  2  moves at a constant speed and the laser cuts the electrode plate  2  while moving obliquely in the opposite direction to the transfer direction of the electrode plate  2 , the angle of the relative speed of the laser with respect to the electrode plate  2  is 90°, and thus the uncoated portion  2 B of the electrode plate  2  is cut at a right angle at the exit portion (see  FIG.  6   ). 
     Consequently, the laser cuts the electrode plate  2  while moving in the first oblique direction D 1 , the longitudinal direction D 2 , and the second oblique direction D 3  as the electrode plate  2  moves at a constant speed in the transfer direction, whereby the tabs  2 C are formed at regular intervals in the uncoated portion  2 B of the electrode plate  2  (see  FIG.  7   ). 
     However, the conventional method has some problems. That is, it is difficult to discharge the scrap, the scrap is often blown over the electrode plate, and the size and position of the scrap discharge hole needs to be adjusted according to the speed of the electrode plate and the size of the scrap due to high sensitivity to the speed of the electrode plate. 
     In addition, when the scrap suction flow rate is increased, the tab of the electrode plate is sucked into the scrap discharge hole and crumpled. When the tab of the electrode plate is sucked in and crumpled, a defect occurs in the electrode plate, and the tab forming process and the suction process need to be stopped and reset to restart the operation. This is not desirable in terms of work efficiency and productivity. 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and an objective of the present disclosure is to provide a conveyor for discharging scrap of a laser notching machine and a scrap discharge method thereof, the conveyor having a new configuration capable of efficiently discharging scrap resulting from forming a tab by laser notching during continuous transfer of an electrode plate. 
     Technical Solution 
     In order to accomplish the above objective, the present disclosure provides a conveyor for discharging scrap of a laser notching machine, the conveyor including: a conveyor; a suction part connected to the conveyor and configured to suck scrap resulting from forming a tab in an electrode plate passing through the conveyor; and a scrap discharge hole configured to suck and discharge the scrap from the conveyor. 
     Advantageous Effects 
     The present disclosure has the following useful effect. That is, it is possible to efficiently discharge scrap resulting from forming a tab in an electrode plate; it is possible to prevent the scrap from being blown over the electrode plate; it possible to eliminate the need to adjust the size and position of a scrap discharge hole according to the speed of the electrode plate and the size of the scrap; and it is possible to prevent the tab of the electrode plate from being sucked into the scrap discharge hole and crumpled. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view illustrating a conventional scrap discharge method. 
         FIG.  2    is a sectional view illustrating the conventional scrap discharge method. 
         FIG.  3    is a plan view conceptually illustrating a laser cutting process of forming a tab in an electrode plate. 
         FIG.  4    is a view illustrating the laser cutting process performed at an entry portion while moving the electrode plate at a constant speed. 
         FIG.  5    is a view illustrating the laser cutting process performed in the longitudinal direction of the electrode plate while moving the electrode plate at the constant speed. 
         FIG.  6    is a view illustrating the laser cutting process performed at an exit portion while moving the electrode plate at the constant speed. 
         FIG.  7    is a view illustrating a movement path of a laser for forming the tab in the electrode plate moving at the constant speed. 
         FIG.  8    is a perspective view illustrating a conveyor for discharging scrap of a laser notching machine according to an embodiment of the present disclosure. 
         FIG.  9    is a front view illustrating a scrap discharge process of the conveyor for discharging scrap of the laser notching machine illustrated in  FIG.  8   . 
         FIG.  10    is a bottom view illustrating the scrap discharge process of the conveyor for discharging scrap of the laser notching machine illustrated in  FIG.  8   . 
         FIG.  11    is a front view illustrating a scrap discharge process of the conveyor for discharging scrap of the laser notching machine according to the present disclosure in which scrap is discharged through a scrap discharge hole of a scrap discharge duct by air suction. 
         FIG.  12    is a perspective view illustrating a conveyor for discharging scrap of a laser notching machine according to another embodiment of the present disclosure. 
         FIG.  13    is a front view illustrating a scrap discharge process the conveyor for discharging scrap of the laser notching machine illustrated in  FIG.  12    in which scrap is discharged through a scrap discharge hole of a scrap discharge duct by air suction. 
         FIG.  14    is a front view illustrating a scrap discharge process of a conveyor for discharging scrap of a laser notching machine according to still another embodiment of present disclosure in which scrap is discharged through a scrap discharge hole of a scrap discharge duct by air suction. 
     
    
    
     BEST MODE 
     The present disclosure relates to a conveyor for discharging scrap of a laser notching machine, the conveyor including: a conveyor; a suction part connected to the conveyor and configured to suck scrap resulting from forming a tab in an electrode plate passing through the conveyor; and a scrap discharge hole configured to suck and discharge the scrap from the conveyor. The conveyor includes: a conveyor body; and a conveyor belt configured to move along a continuous track so as to pass over upper and lower surfaces of the conveyor body, and a vacuum sector is provided in a transfer path through which the electrode plate passes. The vacuum sector is provided with a vacuum hole communicating from an inner space of the conveyor body to the lower surface of the conveyor body, the scrap discharge hole is disposed under the conveyor belt, and the suction part includes a suction duct communicating with the inner space of the conveyor body. 
     Mode for Invention 
     A conveyor for discharging scrap of a laser notching machine according to the present disclosure includes a conveyor  20  disposed such that a reel electrode plate  2  (hereinafter, referred to as an electrode plate for convenience) passes through the conveyor  20  under the conveyor  20 , a suction part for sucking scrap  2 S resulting from forming a tab  2 C in the electrode plate  2 , and a scrap discharge hole  34  for sucking and discharging the scrap  2 S. In this case, the suction part includes a suction duct  52  communicating with an inner space of a conveyor body  22 . The suction part is a means capable of applying a vacuum pressure to the inner space of the conveyor body  22 . 
     The conveyor  20  includes the conveyor body  22  and a conveyor belt  24 . 
     The conveyor body  22  is configured in a rectangular plate shape. The conveyor body  22  is disposed above the electrode plate  2  passing along a transfer line. The conveyor body  22  is configured in a plate shape having a space therein. A vacuum sector  22 VS and a vacuum release sector  22 RS are provided along the transfer path through which the electrode plate  2  passes. The conveyor body  22  may be configured to include the vacuum sector  22 VS and the vacuum release sector  22 RS so that the vacuum sector  22 VS and the vacuum release sector  22 RS are provided along the transfer path of the electrode plate  2 . The vacuum sector  22 VS and the vacuum release sector  22 RS may be configured to be partitioned by a diaphragm provided inside the conveyor body  22 . The vacuum sector  22 VS is configured to have a plurality of vacuum holes communicating from the inner space of the conveyor body  22  to a lower surface of the conveyor body  22 . The vacuum release sector  22 RS has no vacuum hole. 
     The conveyor belt  24  moves along a continuous track so as to pass over upper and lower surfaces of the conveyor body  22 . A pair of rollers  23  are provided at portions adjacent to an electrode plate inlet end and an electrode plate outlet end of the conveyor body  22 , respectively. The roller  23  installed adjacent to the electrode plate outlet end is connected to a motor shaft of a servomotor  25  for conveyor driving. The conveyor belt  24  is coupled to the pair of rollers  23  and disposed on the upper and lower surfaces of the conveyor body  22 . As the motor shaft of the servomotor  25  rotates, the conveyor belt  24  moves along a continuous track so as to pass over the upper and lower surfaces of the conveyor body  22 . The conveyor belt  24  is provided with a plurality of vacuum suction holes formed through opposite surfaces thereof. When vacuum pressure is applied to the space in which the vacuum holes of the conveyor body  22  are formed, a vacuum pressure capable of adsorbing the scrap  2 S resulting from forming the tab  2 C of the electrode plate  2  is applied to the vacuum suction holes of the conveyor belt  24  through the vacuum holes. In this case, the scrap discharge hole  34  is disposed under the conveyor belt  24 . The scrap  2 S adsorbed to the conveyor belt  24  is sucked into and discharged through the scrap discharge hole  34  by air suction pressure. 
     The electrode plate  2  has a coated portion  2 A and an uncoated portion  2 B. A part of each of the conveyor body  22  and the conveyor belt  24  is disposed above the uncoated portion  2 B of the electrode plate  2  passing thereunder. 
     The suction duct  52  is connected to the conveyor body  22 . In other words, the suction duct  52  is connected to an inner space of the vacuum sector  22 VS of the conveyor body  22 . The suction duct  52  is connected to a vacuum device (not illustrated). Vacuum pressure generated in the vacuum device is applied to the inner space of the vacuum sector  22 VS of the conveyor body  22  through the suction duct  52 . When the vacuum pressure is applied to the inner space of the vacuum sector  22 VS, the vacuum pressure is applied to a lower surface of the conveyor belt  24  through the plurality of vacuum holes and the plurality of vacuum suction holes of the conveyor belt  24 . When the vacuum pressure is applied to the lower surface of the conveyor belt  24  passing over the lower surface of the conveyor body  22 , the scrap  2 S resulting from forming the tab  2 C in the uncoated portion  2 B of the electrode plate  2  is adsorbed to the lower surface of the conveyor belt  24  by the vacuum pressure. In other words, the suction duct  52  allows the conveyor  20  to suck the scrap  2 S resulting from forming the tab  2 C in the electrode plate  2  passing through the conveyor  20  by the vacuum pressure. Specifically, the scrap  2 S is sucked and adsorbed in the vacuum sector  22 VS of the conveyor  20 . Since the scrap  2 S is sucked in the vacuum sector  22 VS of the conveyor body  22  by the vacuum pressure so as to be adsorbed on the lower surface of the conveyor belt  24 , it can be said that the scrap  2 S is sucked in the vacuum sector  22 VS of the conveyor  20 . 
     A scrap discharge duct  32  is provided under the vacuum release sector  22 RS of the conveyor body  22 . The scrap discharge hole  34  is provided inside the scrap discharge duct  32 . An air suction device (not illustrated) is connected to the scrap discharge duct  32 , so that an air pressure capable of sucking the scrap  2 S is applied to the scrap discharge hole  34  inside the scrap discharge duct  32  by the air suction device. 
     Meanwhile, the present disclosure provides a scrap discharge method of a conveyor for a laser notching machine, the method including a scrap suction step of sucking scrap  2 S, which results from forming a tab  2 C in an electrode plate  2  passing through a conveyor  20 , in a vacuum sector  22 VS of the conveyor  20  by vacuum pressure so as to be adsorbed to a lower portion of the conveyor  20 , a scrap transfer step of transferring the scrap  2 S to a vacuum release sector  22 RS of the conveyor  20 , and a scrap discharge step of sucking the scrap  2 S into the scrap discharge hole  34  under the vacuum release sector  22 RS and discharging the scrap  2 S. 
     In the scrap suction step, the scrap  2 S remaining after forming the tab  2 C in the electrode plate  2  is sucked in the vacuum sector  22 VS of the conveyor body  22  by vacuum pressure so as to be adsorbed to a conveyor belt  24  passing over a lower surface of the conveyor body  22 . 
     In the scrap transfer step, the scrap  2 S is transferred to the vacuum release sector  22 SS of the conveyor  20 . In the scrap discharge step, the scarp  2 S is sucked into the scrap discharge hole  34  under the vacuum release sector  22 RS and discharged by air suction in a state in which the vacuum pressure is released in the vacuum release sector  22 RS. 
     According to the present disclosure having the above configuration, a plurality of tabs  2 C are formed at regular intervals in the uncoated portion  2 B of the electrode plate  2  while a laser moves along a laser slit  2 SL. In other words, the laser cuts the electrode plate  2  while moving in the first oblique direction D 1 , the longitudinal direction D 2 , and the second oblique direction D 3  as the electrode plate  2  moves at a constant speed in the transfer direction, whereby the tabs  2 C are formed at regular intervals in the uncoated portion  2 B of the electrode plate  2 . A fume exhaust duct  7  is provided adjacent to the laser slit  2 SL. The fume exhaust duct  7  sucks and discharges foreign substances resulting from laser cutting of the tabs  2 C in the electrode plate  2 . 
     The scrap  2 S resulting from forming the tabs  2 C in the electrode plate  2  is discharged through the scrap discharge hole  34  provided in the scrap discharge duct  32 . In other words, the scrap  2 S resulting from forming the tab  2 C in the electrode plate  2  is sucked in the vacuum sector  22 VS of the conveyor body  22  by vacuum pressure so as to be adsorbed to the conveyor belt  24  passing over the lower surface of the conveyor body  22 , and then the scrap  2 S is sucked into the scrap discharge hole  34  under the vacuum release sector  22 RS by air suction in a state in which the vacuum pressure is released in the vacuum release sector  22 RS. 
     The scrap discharge duct  32  is disposed under the vacuum release sector  22 RS of the conveyor  20  (precisely, the vacuum release sector  22 RS of the conveyor body  22 ), so that when the scrap  2 S that has passed the vacuum sector  22 VS of the conveyor  20  enters the vacuum release sector  22 RS, the vacuum acting on the scrap  2 S is released. Thus, the scrap  2 S resulting from forming the tabs  2 C in the electrode plate  2  is separated from the conveyor belt  24  downwards, and when the scrap  2 S may pass above the scrap discharge duct  32 , a suction force (e.g., air suction pressure) is applied to the scrap discharge hole  34  to cause the scrap  2 S released from the conveyor belt  24  to be sucked downwards into the scrap discharge hole  34  and discharged to the outside through the scrap discharge duct  32 . 
     On the other hand, the scrap discharge duct  32  may be provided at a position outside the electrode plate outlet end of the conveyor body  22  so that the scrap discharge hole  34  is provided next to the electrode plate outlet end of the conveyor body  22 . In this case, provision of the diaphragm in the inner space of the conveyor body  22  is omitted, the suction duct  32  is connected to the inner space of the conveyor body  22  so that the entire inner space of the conveyor body  22  forms the vacuum sector  22 VS, and the vacuum suction holes are formed in the entire lower surface of the conveyor body  22 . Thereby, the vacuum is automatically released at the position past the electrode plate outlet end of the conveyor body  22  (i.e., the position where the electrode plate  2  and the scrap  2 S have passed the vacuum sector  22 VS), so that when the scrap  2 S resulting from forming the tabs  2 C in the electrode plate  2  enters the position past the electrode plate outlet end of the conveyor body  22 , the scrap  2 S is sucked into the scrap discharge hole  34  by the air suction pressure acting on the scrap discharge hole  34  inside the scrap discharge duct  32  and discharged (see  FIGS.  12  and  13   ). 
     Here, the present disclosure is configured such that the air suction pressure acting on the scrap discharge hole  34  is stopped when the tabs  2 C formed in the electrode plate  2  pass the scrap discharge hole  34 . In other words, after the scrap  2 S is sucked into and discharged through the scrap discharge hole  34  by the air suction pressure, the tabs  2 C of the electrode plate  2  pass above the scrap discharge hole  34 . At this time, the air suction pressure acting on the scrap discharge hole  34  is released. The release of the air suction pressure may be achieved by stopping the operation of the air suction device (not illustrated) connected to the scrap discharge hole  34  when the tabs  2 C of the electrode plate  2  pass above the scrap discharge hole  34 . 
     The characteristics of the conveyor for discharging scrap according to the present disclosure are summarized as follows. 
     The present disclosure is controlled by the servomotor  25 , so that the transfer speed of the electrode plate  2  and the rotation speed of the conveyor belt  24  are the same. 
     The vacuum suction holes (i.e., the vacuum suction holes) are provided in the conveyor belt  24 . 
     The scrap  2 S cut out by the laser is adsorbed to the lower portion of the conveyor belt  24  of the conveyor  20  and transferred rearwards. The scrap  2 S being transferred rearwards means that the scrap  2 S is transferred to the vacuum release sector  22 RS of the conveyor  20 . 
     The suction force is removed at the position above the scrap discharge hole  34 , so that the scrap  2 S is separated from the conveyor belt  24 . As the suction force is released in the vacuum release sector  22 RS of the conveyor  20 , the scrap  2 S becomes separable from the conveyor belt  24 . 
     The scrap  2 S is discharged through the scrap discharge hole  34  by air suction. In other words, in a state in which the vacuum pressure holding the scrap  2 S on the lower surface of the conveyor belt  24  in the vacuum release sector  22 RS of the conveyor  20  is released, the scrap  2 S is discharged through the scrap discharge hole  34  inside the scrap discharge duct  32  by air suction. 
     Therefore, in the present disclosure, it is possible to efficiently discharge the scrap  2 S, it is possible to prevent the scrap  2 S from being blown over the electrode plate  2 , and low sensitivity to the speed of the electrode plate  2  makes it possible to eliminate the need to adjust the size and position of the scrap discharge hole  34  according to the speed of the electrode plate  2  and the size of the scrap  2 S. 
     Furthermore, in the present disclosure, the air suction pressure acting on the scrap discharge hole  34  is stopped when the tabs  2 C formed in the electrode plate  2  pass the scrap discharge hole  34 . This prevents the tabs  2 C of the electrode plate  2  from being sucked into the scrap discharge hole  34  and crumpled. 
     By preventing the tabs  2 C of the electrode plate  2  from being sucked in and crumpled, it is possible to prevent a defect from occurring in the electrode plate  2 , and there is no need to stop and reset the tab forming process and the suction process to restart the operation. This is very advantageous in terms of work efficiency and productivity. 
     Meanwhile, in the present disclosure, a guide shield  66  may be further provided above the scrap discharge hole  34 . The guide shield  66  may be supported by the scrap discharge duct  32  through a connection piece connected to the scrap discharge duct  32  or may be supported by another support such as a bracket so that the guide shield  66  is located above the scrap discharge hole  34 . Preferably, the guide shield  66  is configured as a curved plate and a front end of the guide shield  66  is spaced a predetermined distance from a front inner surface of the scrap discharge duct  32  so that a sufficient suction space for the scrap  2 S to be sucked in is secured between the front end of the guide shield  66  and the front inner surface of the scrap discharge duct  32 . 
     Therefore, when the tabs  2 C formed in the electrode plate  2  pass above the guide shield  66 , the guide shield  66  blocks the air suction pressure acting on the scrap discharge hole  34 , thereby preventing the tabs  2 C from being sucked into the scrap discharge hole  34  by the air suction pressure. At the same time, the scrap  2 S is efficiently sucked into and discharged through the suction space secured between the front end of the guide shield  66  and the front inner surface of the scrap discharge duct  32 , so it is possible to prevent the tabs  2 C of the electrode plate  2  from being crumpled during transfer. Preferably, a downwardly extending curved guide plate  66 CP is provided at the front end of the guide shield  66 , so that when the electrode plate  2  and the tabs  2 C pass, the tabs  2 C are guided by the curved guide plate  66 CP so as to pass above the guide shield  66  more reliably without being caught by the front end of the guide shield  66 , and the scrap  2 S of the electrode plate  2  is more reliably sucked into the scrap discharge hole  34  inside the scrap discharge duct  32  by the curved guide plate  66 CP. 
     INDUSTRIAL APPLICABILITY 
     A conveyor for discharging scrap of a laser notching machine according to the present disclosure includes: a conveyor; a suction part connected to the conveyor and configured to suck scrap resulting from forming a tab in an electrode plate passing through the conveyor; and a scrap discharge hole configured to suck and discharge the scrap from the conveyor. The conveyor according to the present disclosure has industrial applicability as a conveyor for use in discharging scrap of a laser notching machine.