Patent Publication Number: US-2011048210-A1

Title: Cutting apparatus of winder for secondary battery

Description:
BACKGROUND 
     1. Field 
     Example embodiments relate to a cutting apparatus of a winder for a secondary battery. More particularly, example embodiments relate to a cutting apparatus of a winder for a secondary battery, which can increase the number of products produced per unit time by reducing the production index of the winder for the secondary battery. 
     2. Description of the Related Art 
     As the development and demand for mobile technologies have recently increased, demand for secondary batteries, as an energy source, has been rapidly increasing. Accordingly, studies of batteries have been conducted to satisfy various requirements. Particularly, there is a high demand for lithium secondary batteries exhibiting high energy density, high discharge voltage, and high output stability. 
     Generally, in a secondary battery, an anode and a cathode may be formed by coating active materials on surfaces of a current collector, respectively, and an electrode assembly may be manufactured by interposing a separator between the anode and cathode. Then, the electrode assembly may be inserted into, e.g., a metallic cylinder-shaped or square-shaped container or a pouch-shaped case made of an aluminum laminated sheet. The secondary battery may be manufactured, e.g., by injecting or pouring a liquid electrolyte into the electrode assembly or by using a solid electrolyte. 
     The electrode assembly may be manufactured to have various sizes in accordance with sizes and shapes of an outer case of the secondary battery and/or in accordance with capacities required in its application fields. Therefore, it may be necessary to perform a process of cutting an electrode into a predetermined size to form a cathode and/or an anode of the electrode assembly. 
     SUMMARY 
     Embodiments are therefore directed to a cutting apparatus of a winder for a secondary battery, which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art. 
     It is therefore a feature of an embodiment to provide a cutting apparatus of a winder for a secondary battery, in which an electrode is cut by using a rotary cutter type cutting apparatus while not being stopped but being continuously transferred, so that the production index of the winder for secondary battery can be reduced, thereby increasing the number of products produce per unit time. 
     At least one of the above and other features and advantages may be realized by providing a cutting apparatus of a winder for a secondary battery, the apparatus including a cutting roll contacting a first side of a material, the cutting roll having a cutter protruding through an outer circumferential surface of the cutting roll to contact the first side of the material during cutting, an anvil roll facing the cutting troll and contacting a second side of the material, the cutting roll and the anvil roll being configured to contact each other via the material only at predetermined process stages, and a controller configured to move the cutting roll and/or the anvil roll to contact each other via the material during the predetermined process stages. 
     The anvil roll may be movable along a linear direction, and the controller may include a speed controller configured to control a rotating speed of the cutting roll, and a position controller configured to control a space between the cutting and anvil rolls by moving the anvil roll along the linear direction. The speed controller may control the rotating speed of the cutting roll to be changed into a uniform speed or arbitrary speed. 
     The apparatus may further include a sensor formed prior to the cut position of the material. The sensor may sense the cut position of the material to transmit it to the control system. 
     A frictional force being in contact with the material may be further formed on at least one of the outer circumferential surface of the cutting roll except the region having the cutter formed therein and the outer circumferential surface of the anvil roll. 
     The frictional force reinforcing portion may be formed of any one selected from the group consisting of urethane, rubber, acryl and silicon. 
     The frictional force reinforcing portion may have a surface subjected to concave-convex or embossing treatment so that the sectional area of the surface of the cutting roll is increased. 
     The anvil roll may be in contact with the cutting roll by the position controller only when the material is cut. 
     The speed controller may control the rotating speed of the cutting roll to be changed into a uniform speed or arbitrary speed. 
     The cutting roll may include a contact portion and a non-contact portion, the contact portion being configured to contact the first side of the material during rotation of the cutting roll, and the non-contact portion being configured not to contact the first side of the material during rotation of the cutting roll, and the controller is a speed controller configured to control a rotating speed of the cutting roll. The speed controller may be configured to vary the rotating speed of the cutting roll from a uniform speed to an arbitrary speed. The speed controller may be configured to set the arbitrary speed of the cutting roll to zero. The non-contact portion may be configured to face the first side of the material when the arbitrary speed is zero. 
     The cutting roll may include a frictional force reinforcing portion on at least one of the contact portion of the cutting roll and an outer circumferential surface of the anvil roll. The anvil roll may be configured to constantly be in contact with the material. A distance between a center of the cutting roll to an outermost circumference of the contact portion is larger than a distance between the center of the cutting roll and an outermost circumference of the non-contact portion. 
     At least one of the above and other features and advantages may also be realized by providing a cutting apparatus including a cutting roll contacting a first side of a material, the cutting roll having a cutter protruding through an outer circumferential surface of the cutting roll to contact the first side of the material during cutting, and an anvil roll facing the cutting troll and contacting a second side of the material. 
     A frictional force reinforcing portion being in contact with the material may be further formed on at least one of the outer circumferential surface of the cutting roll except the region having the cutter formed therein and the outer circumferential surface of the anvil roll. A lithium secondary battery may be manufactured using a material cut by the aforementioned apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which: 
         FIG. 1  illustrates a cross-sectional view of a rotary cutter type cutting apparatus according to an embodiment; 
         FIG. 2  illustrates a cross-sectional view of the moment when an electrode is cut by the cutting apparatus according to an embodiment; 
         FIG. 3  illustrates an enlarged cross-sectional view of a shape of the cut electrode in  FIG. 2 ; 
         FIG. 4  illustrates a cross-sectional view of the moment when the electrode is not cut by the cutting apparatus according to an embodiment; 
         FIG. 5A  illustrates a cross-sectional view of the moment when an electrode is cut by a rotary cutter type cutting apparatus according to another embodiment; 
         FIG. 5B  illustrates a cross-sectional view of the moment when the electrode is transferred by the rotary cutter type cutting apparatus according to the other embodiment; 
         FIG. 5C  illustrates a cross-sectional view of the moment when the electrode is not cut by the cutting apparatus according to the embodiment; and 
         FIG. 6  illustrates a cross-sectional view of a rotary cutter type cutting apparatus according to still another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Korean Patent Application No. 10-2009-0082974, filed on Sep. 3, 2009, in the Korean Intellectual Property Office, and entitled: “Cutting Apparatus of Winder for Secondary Battery,” is incorporated by reference herein in its entirety. 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when an element is referred to as being “on” another element or substrate, it can be directly on the other element or substrate, or intervening elements may also be present. In addition, it will also be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present. Also, when an element is referred to as being “connected to” another element, it can be directly connected to the other element or be indirectly connected to the other element with one or more intervening elements interposed therebetween. Hereinafter, like reference numerals refer to like elements throughout. 
       FIG. 1  illustrates a cross-sectional view of a rotary cutter type cutting apparatus according to an embodiment.  FIG. 2  illustrates an enlarged cross-sectional view of the rotary cutter of  FIG. 1  during cutting according to an embodiment. 
     Referring to  FIG. 1 , a winder may include a turret  20 , a plurality of guide rolls  18  for supporting a separator  17 , and a rotary cutter  10 . The rotary cutter  10  may be the rotary cutter type cutting apparatus according to an embodiment. 
     Referring to  FIGS. 1 and 2 , the rotary cutter  10  may be used for cutting a material  14  to have a desired length. A cutting roll  11  may be formed at one side of the material  14 , and an anvil roll  13  may be formed at the other side of the material  14  to face the cutting roll  11 . In other words, the cutting roll  11  and the anvil roll  13  may face each other with the material  14  interposed therebetween. For example, the cutting roll  11  may be formed at a first surface  14   a  ( FIG. 3 ) of the material  14 , and the anvil roll  13  may be formed at a second surface  14   b  ( FIG. 3 ), i.e., a surface opposite the first surface  14   a , of the material  14 . For example, the material  14  may be an electrode. Hereinafter, the “material  14 ” and the “electrode  14 ” may be used interchangeably. 
     A cutter  12  may protrude from an outer circumferential surface  11   b  of the cutting roll  11 . The protruding cutter  12  may be formed to be in contact with the electrode  14  during cutting. For example, the cutter  12  may have a linear shape extending from one point on the outer circumferential surface  11   b  of the cutting roll  11  to protrude through another point on the outer circumferential surface  11   b  into a frictional force reinforcing portion  11   a  of the cutting roll  11  to contact the electrode  14 . 
     The frictional force reinforcing portion  11   a  may be formed on the cutting roll  11 , and may be in contact with the electrode  14 . The frictional force reinforcing portion  11   a  may be formed on a portion of the outer circumferential surface  11   b  of the cutting roll  11 . For example, the frictional force reinforcing portion  11   a  may cover substantially an entire outer circumferential surface  11   b  of the cutting roll  11 , i.e., with the exception of the region where the cutter  12  protrudes the outer circumferential surface  11   b . The frictional force reinforcing portion  11   a  may reinforce the frictional force generated between the electrode  14  and the cutting roll  11 . The frictional force reinforcing portion  11   a  may be formed of one or more of urethane, rubber, acryl, and silicon. The frictional force reinforcing portion  11   a  may have a surface subjected to concave-convex or embossing treatment so that the sectional area of the surface of the cutting roll  11  may be increased. 
     The anvil roll  13  may be formed at the other side of the electrode  14  to face the cutting roll  11 . The anvil roll  13  may support the cutting roll  11  so that the cutter  12  of the cutting roll  11  may press into the electrode  14  when cutting the electrode  14 . For example, the cutting roll  11  and the anvil roll  13  may be arranged along a first direction, e.g., the cutting roll  11  may be on the anvil roll  13  along a vertical direction, so the cutter  12  of the cutting roll  11  may press into the electrode  14  at a tangent point of the cutting roll  11  and the anvil roll  13  when the cutting roll  11  and the anvil roll  13  contact each other. 
     A control system for controlling operations of the cutting and anvil rolls  11  and  13  may be connected to the rotary cutter  10 . The control system may include a speed controller  15  for controlling a rotating speed of the cutting roll  11  and a position controller  16  for controlling a space between the cutting and anvil rolls  11  and  13  by moving the anvil roll  13 . In other words, the cutting roll  11  and the anvil roll  13  may be spaced apart from each other, and when the electrode  14  is required to be cut, the position controller  16  may move the anvil roll  13  toward the cutting roll  11  along the first direction to contact each other via the electrode  14 . 
     Since cutting of the electrode  14  is performed only when the anvil roll  13  and the cutting roll  11  contact each other via the electrode  14 , control of the distance between the anvil roll  13  and the cutting roll  11  via the position controller  16  may facilitate adjustment of a length of the cut electrode  14 , i.e., the length of the cut electrode  14  is not limited to a circumferential length of the cutting roll  11 . The speed controller  15  may vary the rotating speed of the cutting roll  11 , e.g., to be a uniform speed or any arbitrary speed, so that the length of the electrode  14  may be adjusted according to demand, i.e., an arbitrary length and not limited to the circumferential length of the cutting roll  11  or a multiple of the circumferential length. 
     As further illustrated in  FIGS. 1 and 2 , the rotary cutter  10  may include a sensor  19 . The sensor  19  may be positioned before a cutting point of the electrode  14 , i.e., the sensor  19  may face an uncut electrode  14  and a contact point of the cutting and anvil rolls  11  and  13 . In other words, the sensor  19  may be positioned to detect operations of the position and speed controllers  16  and  15 , so operations of the position and speed controllers  16  and  15  may be connected to each other, i.e., synchronized. Accordingly, the cut position of the electrode  14  may be transmitted to the control system. The operations of the speed controller  15 , the position controller  16 , and the sensor  19  will be described in more detail below with reference to  FIGS. 2-4 . 
     Referring to  FIG. 1 , the electrode  14  cut by the rotary cutter  10  may be wound around a winding core  21  together with the separator  17  by the plurality of guide rolls  18 . The turret  20  having a plurality of winding cores  21  formed thereon may be used to increase efficiency of the winding operation. 
     The turret  20  may be a circular disk, and a plurality, e.g., two, of winding cores  21  around which the electrode  14  and the separator  17  are wound together may be formed on the top of the turret  20 . Therefore, the turret  20  may be rotated to wind more than one electrode. For example, before winding of one electrode  14  around one winding core  21  is complete, another electrode may be wound around the other winding core  21 , thereby saving time. Accordingly, the efficiency of the winding operation can be improved. Reference numeral  22  denotes a wound product. 
     Hereinafter, operation of the rotary cutter type cutting apparatus according to an embodiment will be described.  FIG. 2  illustrates a cross-sectional view at the moment when the electrode  14  is cut by the rotary cutter  10 ,  FIG. 3  illustrates a cross-sectional view of a shape of the cut electrode  14 , and  FIG. 4  illustrates a cross-sectional view at the moment when the electrode  14  is not cut. 
     Referring to  FIGS. 2 to 4 , the rotary cutter  10  may include the cutting roll  11  having the cutter  12  protruding from the outer circumferential surface  11   b  thereof, so that the cutter  12  may be in contact with the electrode  14  at one side of the electrode  14  through its rotation. The anvil roll  13  may be formed at the other side of the electrode  14  to face the cutting roll  11  with the electrode  14  interposed therebetween. The speed controller  15  and the position controller  16  may control the rotating speed of the cutting roll  11  and the position of the anvil roll  13 , respectively. The cut position of the electrode  14  may be transmitted by the sensor  19  to the control system, so the operations of the position and speed controllers  16  and  15  may be connected to each other. 
     As illustrated in  FIG. 4 , while being wound on the turret  20 , the electrode  14  may be in contact with the cutting roll  11 , and the anvil roll  13  may be spaced apart from the electrode  14 . In other words, when the electrode  14  is not cut, the position controller  16  may control the anvil roll  13  to be spaced apart from the cutting roll  11 , e.g., the position controller  16  may arbitrarily control the position of the anvil roll  13  with respect to the cutting roll  11 . Therefore, the winding operation may continue without cutting the electrode  14 . 
     When the wound electrode  14  reaches a desired length and the cut position of the electrode  14  is sensed by the sensor  19 , the sensor  19  may transmit the cut position to the position and speed controllers  16  and  15  in the control system. Next, as illustrated in  FIG. 2 , the position controller  16  may move the anvil roll  13  along the first direction to contact the cutting roll  11  via the electrode  14  in order to cut the electrode  14 . The speed controller  16  may be operated in connection with the position controller  15 , e.g., the speed controller  16  may control the rotating speed of the cutting roll  11  not to be a uniform speed but to be an arbitrary speed before the anvil roll  13  is in contact with the cutting roll  11 . Accordingly, when the anvil roll  13  contacts the cutting roll  11  via the electrode  14  at the cut position, the cutter  12  of the cutting roll  11  may be positioned to contact and push into the electrode  14  at the transmitted cut position of the electrode  14 . For example, the cutter  12  may cut the electrode  14 , e.g., only, when the electrode  14  is pressed simultaneously from opposite sides by the anvil roll  13  and the cutting roll  11 . 
     That is, the operation of the anvil roll  13  may be controlled by the position controller  16 , so that the cutting and anvil rolls  11  and  13  may be in contact with each other via the electrode  14  only when the electrode  14  is at the cut position. The cutting and anvil rolls  11  and  13  may be spaced apart from each other when the electrode  14  is not cut. Accordingly, the length of the electrode  14  cut by the cutter  12  may not be limited to the length of the circumferential length of the cutting roll  11 . While the cutting and anvil rolls  11  and  13  are spaced apart from each other, the speed controller  15  may control the rotating speed of the cutting roll  11  not to be changed into a uniform speed but to be changed into an arbitrary speed. Accordingly, the electrode  14  may be cut not to have a multiple of the circumferential length of the cutting roll  11  but to have an arbitrary length. 
     As illustrated in  FIG. 3 , since the anvil roll  13  and the cutting roll  11  contact the electrode  14  simultaneously from opposite surfaces during cutting, the side section of the cut electrode  14  may have a shape in which both corners of the cut end of the cut electrode  14  are pressed. In other words, both first and second surfaces  14   a  and  14   b  of the cut electrode  14  may have inclined surface portions. For example, the inclined surface portion of the first surface  14   a , i.e., a surface close to the cutting roll  11 , may be more inclined than the inclined surface portion of the second surface  14   b , i.e., a surface close to the anvil roll  13 . 
     Once the electrode  14  is cut, the cut electrode  14  may continue moving along the second direction, e.g., may be transferred an arbitrary distance in a direction from the cutting roll  11  toward the turret  20 , by a friction force between the frictional force reinforcing portion  11   a  of the cutting roll  11  and the electrode  14 . The frictional force reinforcing portion  11   a  may be formed of a resin, e.g., urethane, a viscoelastic material, e.g., rubber, or a material processed for enhancing a frictional force on the surface of the cutting roll  11 . That is, the frictional force reinforcing portion  11   a  may increase the frictional force generated between the electrode  14  and the cutting roll  11 , so that the front end of the electrode  14 , after cutting the electrode  14  at the state that the anvil and cutting rolls  13  and  11  are closely in contact with each other, may be transferred to a position at which a next electrode may be wound on the turret  20 . For example, the cutting roll  11  may rotate continuously, so after cutting one electrode  14 , a next electrode may be wound on the turret continuously without stopping the winding and/or cutting processes. 
     In other words, by using the rotary cutter  10  according to an embodiment, the electrode  14  may be cut without instantaneous stops, i.e., while being continuously moved. Accordingly, the production index of the winder for the secondary battery may be reduced, and therefore, a number of products produced per unit time may be increased, thereby improving productivity. In contrast, a conventional cutter, e.g., a shear type cutter, may require deceleration of an electrode to a stop in order to facilitate cutting of the electrode by blades, followed by gradual acceleration of the electrode to be advanced toward a winding core to form a jelly roll of wound electrode and separator. As such, winding of the conventionally-cut electrode is not continuous, thereby resulting in direct production loss caused by time loss. Further, when the conventionally-cut electrode is accelerated/decelerated, an abrupt change in tension applied to the electrode may result in a thickness change in the electrode, thereby lowering quality of the products. Another conventional cutter, e.g., a laser, may require expensive equipment and a slow cutting speed, thereby resulting in economic disadvantages. 
     Hereinafter another embodiment will be described with reference to  FIGS. 5A-5C .  FIG. 5A  illustrates a cross-sectional view of a rotary cutter at the moment when an electrode is cut.  FIG. 5B  illustrates a cross-sectional view of the rotary cutter at the moment when the electrode is transferred.  FIG. 5C  illustrates a cross-sectional view of a rotary cutter at the moment when the electrode is not cut. 
     Referring to  FIGS. 5A to 5C , a rotary cutter type cutting apparatus according to an embodiment may include a cutting roll  36  formed at one side of an electrode  34 , an anvil roll  32  formed at the other side of the electrode  34  to face the cutting roll  36 , a speed controller  35  for controlling the rotating speed of the cutting roll  36 , and a sensor  37 . 
     The cutting roll  36  may include a contact portion  36   a  in contact with the electrode  34 , a cutter  33  protruding from an outer circumferential surface of the contact portion  36   a , and a non-contact portion  36   b  not in contact with the electrode  34  even when the cutting roll  36  is rotated. The sensor  37  may be formed prior to the cut position of the electrode  34 , so if a cut position of the electrode  34  is sensed, the sensor  37  may transmit the cut position of the electrode  34  to the speed controller  35 . 
     The contact portion  36   a  of the cutting roll  36  may include a frictional force reinforcing portion  31  along a portion of an outer circumferential surface of the cutting roll  36  to define a first circumferential portion  36   c . The non-contact portion  36   b  may define a second circumferential portion  36   d . The first and second circumferential portions  36   c  and  36   d  may be different from each other, and may not overlap each other. A distance between the second circumferential portion  36   d  to a center of the cutting roll  36  may be smaller than a radius of the cutting roll  36 , i.e., a distance from the center of the cutting roll  36  to first circumferential portion  36   c . Therefore, when the cutting roll  36  is adjusted to have the first circumferential portion  36   c  contact the electrode  34 , i.e., a distance between the electrode  34  and the center of the cutting roll  36  may equal the radius of the cutting roll  36 , the second circumferential portion  36   d  may not contact the electrode  34  during rotation of the cutting roll  36 . In this embodiment, the non-contact portion  36   b  may be formed so that a side section of the cutting roll  36 , i.e., the second circumferential portion  36   d , has a straight line shape. However, the side section of the cutting roll  36  may have any suitable shape, as long as the non-contact portion  36   b  of the cutting roll  36  is not in contact with the electrode  34  when the cutting roll  36  is rotated. 
     Referring to  FIG. 5A , when the sensor  37  senses the cut position of the electrode  34 , during winding of the electrode  34  via rolls (not shown) for supporting the electrode  34 , the sensor  37  may transmit the cut position of the electrode  34  to the speed controller  35 . Accordingly, the speed controller  35  may control the rotating speed of the cutting roll  36  to be a uniform speed or an arbitrary speed. Then, the cutting roll  36  may be rotated, so that the cutter  33  may be positioned at the cut position to cut the electrode  34 . The cutter  33  may be any suitable cutter, e.g., a linear cutter extending from the cutting roller  36  through the frictional force reinforcing portion  31  to contact the electrode  34 , as long as the cutter  34  is configured to protrude from the outer circumferential surface of the contact portion  36   a  to contact the electrode  34 . 
     Subsequently, referring to  FIG. 5B , the frictional force reinforcing portion  31  formed on the outer circumferential surface of the cutting roll  36  may allow the electrode  34  to be transferred to the position at which the front end of the cut electrode  34  may be wound in the state that the cutting roll  36  is in contact with the anvil roll  32 . In other words, a contact between the cutting roll  36  and the anvil roll  32  via the electrode  34  may generate a frictional force to continue movement of the electrode  34  after cutting. Operation and composition of the frictional force reinforcing portion  31  may be substantially the same as those of the frictional force reinforcing portion  11   a.    
     Subsequently, referring to  FIG. 5C , if the electrode  34  is transferred to the position at which the cut electrode  34  can be wound, the rotating speed of the cutting roll  36  may be controlled by the speed controller  35  so that the non-contact portion  36   b  of the cutting roll  36  may be positioned on the electrode  34 . That is, when the electrode  34  is not cut, the rotating speed of the cutting roll  36  may be controlled so the cutter  33  of the cutting roll  36  may not, e.g., directly, contact the electrode  34 , and the non-contact portion  36   b  may face the electrode  34  with a space therebetween, e.g., the speed controller  35  may adjust the rotating speed of the cutting roll  36  to zero. Accordingly, the length of the electrode  34  may be set not to be limited to the circumferential length of the cutting roll  36 . 
       FIG. 6  illustrates a cross-sectional view of a rotary cutter type cutting apparatus according to another embodiment. It is noted that the rotary cutter in  FIG. 6  may be an apparatus used in producing only single products. 
     Referring to  FIG. 6 , a cutting roll  41  may be formed to be in contact with an electrode  44  at one side of the electrode  44 . The cutting roll  41  may include a cutter  43  protruding from an outer circumferential surface thereof. An anvil roll  42  may be formed to be in contact with the electrode  44  at the other side of the electrode  44 . The cutting and anvil rolls  41  and  42  may face each other with the electrode  44  interposed therebetween. The outer circumferential surface of the cutting roll  41  may be formed as a frictional force reinforcing portion  45 . The frictional force reinforcing portion  45  may cover substantially the entire outer circumferential surface of the cutting roll  41 , i.e., with the exception of a region of the cutter  43 . Operation and composition of the frictional force reinforcing portion  45  may be substantially the same as those of the frictional force reinforcing portion  11   a.    
     In the case of the single products electrodes required in the single products may have the same length. Therefore, the length of the electrode  44  may be set to correspond to the circumferential length of the cutting roll  41 , thereby continuously cutting the electrode  44  as the cutting roll  41  rotates. 
     As described above, according to various embodiments, an electrode may be cut by rotary cutter type cutting apparatus while not being instantaneously stopped but being continuously moved. Accordingly, the production index of the winder for a secondary battery may be reduced, and therefore, a number of products produced per unit time may be increased, thereby improving productivity. Further, production lines may be configured by reducing equipment as productivity is improved, thereby saving equipment investment cost and reducing a processing area necessary for equipments. For example, the electrode produced according to embodiments may be applied to lithium secondary batteries. 
     In embodiments, a frictional force reinforcing portion may be formed only on an outer circumferential surface of a cutting roll. It is noted, however, that other configurations of the frictional force reinforcing portion, e.g., the frictional force reinforcing portion may be formed only on an outer circumferential surface of an anvil roll or on outer circumferential surfaces of both the cutting and anvil rolls. 
     Exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.