Patent Publication Number: US-2021194090-A1

Title: Battery electrode plate production line and method

Description:
REFERENCE TO CO-PENDING APPLICATION 
     This application claims priority to U.S. Provisional Application No. 62/680,143 filed Jun. 4, 2018, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to battery electrode plate assemblies and more particularly to a production line and method of making, pasting and applying separators to electrodes of battery plate assemblies. 
     BACKGROUND 
     Electric storage batteries may include bipolar plates and an electrolyte. A lead acid battery may include a plurality of bi-polar plates and a sulfuric acid electrolite. The bi-polar plate may include a frame or substrate with electrodes on both sides, an absorbent glass mat (AGM) separator with a positive paste (active material) applied to one of the electrodes and a negative paste with an AGM separator applied to the other electrode. 
     Prior approaches to applying the battery paste and an AGM separator to an electrode of a bi-polar battery plate have a low rate of mass production and require a significant capital investment for a specially designed production line and equipment to do so. 
     SUMMARY 
     A method of making, pasting and applying separators to substrates of a battery plate may include providing a longitudinally elongate web of separator material having first and second opposites sides, applying a layer of battery paste to one of the first and second sides of the web, severing the pasted web into a series of separate individual separators with paste on the one side, disposing a separate separator of the series on one of a series of substrates with the pasted one side facing the substrate on which it is disposed. To dispose an individual separator on a substrate, the separator may be turned over end for end by reversing its direction of travel relative to the direction of travel of the web before such separator was severed from the web. After an individual separator is disposed on its associated substrate such substrate may be turned over and the foregoing steps repeated to dispose another individual separator on the other side of such substrate. 
     The substrate may include a planar panel portion with at least one and usually a plurality of spaced apart protuberances projecting outwardly of both sides of the panel and before pasting a corresponding hole or holes may be formed through the web so that each pasted individual separator may be disposed on one substrate with each of the one or more protuberances received within a hole of the separator deposited on the one substrate. The substrate may include an edge extending around the panel and projecting outwardly thereof and each individual separator may be disposed within the edge of its associated substrate. 
     A mass production line for making, pasting and applying an individual separator to a substrate may include advancing a longitudinally elongate web of separator material through a paster to apply a layer of paste to one side of the web, severing the web to produce a series of separate individual separators of a desired predetermined length with paste on the one side, a transfer mechanism disposing an individual separator on one of a series of substrates with the pasted one side facing the substrate on which it is disposed. Upstream of the paster a wound roll of a web of separator material may be unwound from the roll and disposed on a moving belt advancing the web under a hopper of a pasting machine to apply paste to one side of the web, and downstream of the paster the pasted web may be received on a rotating transfer cylinder and the pasted web may be separated into individual separators on the cylinder. The cylinder may dispose one of the individual separators on one of a series of substrates being advanced with respect to the transfer cylinder. The transfer cylinder may have vacuum ports retaining the individual separators on the cylinder and the vacuum may be relieved to dispose the separators on the substrates. The separators may be disposed on substrates being advanced in a direction generally opposite to the direction in which the pasted web is being advanced upstream of the transfer cylinder. 
     Upstream of the paster, holes may be formed through the web to register with protuberances of a separator. The holes may be punched by a die and press mechanism or cut by rotary dies. The holes may correspond to protuberances in the substrate so that an individual separator may be deposited on a substrate with the protuberances received in the holes. A belt advancing the web through the paster may have protrusions or bosses registering with and received in the holes formed through the web so that paste is inhibited from being deposited in the holes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of certain embodiments and best mode will be set forth with reference to the accompanying drawings, in which: 
         FIG. 1  is a pictorial view of a bipolar battery plate; 
         FIG. 2  is an enlarged sectional view taken on line A-A of  FIG. 1 ; 
         FIG. 3  is an enlarged fragmentary sectional view of a portion of  FIG. 2  within the circle B; 
         FIG. 4  is an exploded view of the bipolar plate of  FIG. 1 ; 
         FIG. 5  is an exploded view of a portion of the battery plate of  FIG. 1  illustrating a separator and a layer of paste before they are disposed on a substrate of the battery plate; 
         FIG. 6  is a pictorial and somewhat diagrammatic view of a portion of a production line for making and pasting separators and disposing them on substrates for making battery plates; 
         FIG. 7  is a somewhat diagrammatic side view of the production line of  FIG. 7 ; and 
         FIG. 8  is an enlarged sectional view taken on line C-C of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring in more detail to the drawings,  FIGS. 1-4  illustrate a bipolar plate assembly  10  such as a plate for a lead acid battery with electrically conductive electrodes  12  and  14  received on opposed faces  16  and  18  of a frame or substrate  20  with a layer of paste  22  received on the electrode  16  with a separator  24  over the paste and a layer of paste  26  received on the electrode  18  with a separator  28  over the paste. 
     The substrate  20  may have a generally planar panel  30  with raised edges  32  extending around its perimeter and projecting outwardly from both faces  16  and  18  of the panel. The electrodes, paste and separators may be received within the edges of the substrate. The panel may also include at least one and usually a plurality of spaced apart protuberances  34  arranged in a predetermined configuration and projecting outwardly of both faces of the panel. The protuberances  34  may have a circular perimeter and planar outer faces and at least some of the protuberances may have throughholes  36  which when assembled in a battery may provide channels or passages extending transversely through a series of stacked plates. The substrates  20  may be of a suitable plastic material which may be dielectric. The separators  26  and  28  may have clearance holes  38  in which the protuberances are received. 
     For a bipolar lead acid battery plate  10 , the electrically conductive electrodes  16  and  18  may be a thin sheet of film or lead or lead alloy received on its associated face of the substrate and if desired may be attached to the substrate by a suitable adhesive. To provide an anode, one of the electrodes may be coated with a layer of negative paste (active material) and to provide a cathode, the other electrode may be coated with a layer of positive paste (active material), and the separators may be made of an absorbent glass mat (AGM) or other layer or film of a suitable porous material. The separators and the layers of paste may encircle the protuberances  34  but at least substantially do not overlay the outer faces of the protuberances. The construction of bipolar lead-acid battery plates and their assembly and use in a lead-acid battery is known and understood by persons skilled in the art and thus will not be further described. 
     As shown in  FIGS. 6-8  a mass production line  50  may make and paste a series of separators and apply them to one face of a series of separate substrates. The substrates may then be turned over and a second production line substantially the same as the first line  50  may make and paste a series of separators and dispose them on the other side of the series of substrates to provide battery plates with both electrodes having a layer of paste thereon covered by an associated separator. Typically, one of the production lines  50  would apply a positive paste on a separator received on one side of the substrate and the other line would apply a negative paste and an associated separator received on the other side of the substrate to provide a bipolar battery plate. Unipolar plates or end plates with paste and a separator on only one side of a plate may also be made by a production line  50 . 
     As shown in  FIGS. 6 and 7  the production line  50  may include an unwinding station  52  for a roll  54  of a longitudinally elongate web  56  of an absorbent glass mat (AGM), a station  58  forming clearance holes  38  through the web for receiving protuberances of substrates, a feed station  60  for unwinding the roll  54  of web and moving the web through the hole forming station, a pasting station  62 , a cutter station  64  to sever the pasted web into separate individual separators  26 , 28  of a predetermined length, and a transfer station  66  to dispose an individual pasted separator on an associated one of a series of separate substrates  20  advanced through the transfer station such as by a conveyor  68 . Downstream of the transfer station, desirably the pasted separator may be slightly pressed onto its associated substrate such as by passing them and an underlying portion of a conveyor belt  70  through the nip of a pair of rollers  72  and  74 . This may provide a substantially uniform thickness of the substrates with the paste and separators thereon, ensure good contact of the paste with its associated electrode and sufficiently attach the separator to its associated pasted substrate to facilitate subsequent assembly of plates into a battery. 
     In the unwinding station  52 , a roll of an elongate web  56  of separator material such as an AGM may be received on a rotatable arbor  76  and in operation of the line unwound by the web passing through the nip of a pair of feed rollers  78 , 80  driven for corotation by a desirably variable speed electric motor  82  such as a stepper motor. An adjustable air brake  84  may be connected to the arbor to maintain the web in tension or taut between the feed rollers  78 , 80  and the roll  54  of the web as it is being unwound. If the substrate includes protuberances  34 , corresponding clearance holes  38  may be formed in the web in the station  58  such as by punching dies  86  received in and actuated by a press  88 . Alternatively, the clearance holes in the web could be formed by a pair of rotary dies through the nip of which the web passes with the tangential speed at their nip being the same as the linear speed at which the web is advanced through the forming station by the feed rollers  78 , 80 . The pair of rotary cutting dies may be driven by a variable speed motor such as a stepper motor synchronized with the speed of the feed rollers which may be driven desirably by another stepper motor  82 . Optionally, the hole forming station  58  can be eliminated and any desired clearance holes formed in the web  56  before it is wound into a roll and placed on the arbor  76  of the unwinding station. 
     In the paster station  62  the web may be received on a upper run of a continuous belt  92  received over a pair of spaced apart rollers  94 , 96  journaled for rotation with preferably the downstream roller being driven by a variable speed electric motor  98  such as a stepper motor to advance the web under a paste hopper  100  and through the paster station  62 . The belt may be made of stainless steel and as shown in  FIG. 8  may include circular protrusions or bosses  102  in a configuration complimentary to and received in the corresponding clearance holes  38  in the web and desirably having an outer substantially planar face  104  substantially in the plane of the upper face of the web  56  to inhibit paste applied to the upper face of the web from entering the clearance holes in the web. The paste hopper  100  may be of conventional construction and in operation may discharge paste through an orifice  106  onto the upper or first surface  108  of the web as it is advanced under the orifice. The orifice may extend substantially across the transverse width of the web. 
     Downstream of the paster station, the pasted web may pass into the transfer station  66  and be received on the periphery of a transfer cylinder  110  journaled for rotation and driven by a variable speed motor  112  such as a stepper motor. Desirably, while the web is on the transfer cylinder it may be severed into a series of succeeding separate individual pasted separators  26 , 28  such as by a cutter assembly  114  journaled for rotation and having at least one and desirably a plurality of cutter blades  116  of sufficient length to extend transversely across the web. The speed of rotation of the cutter blades  116  may be synchronized with the rotary speed of the transfer cylinder  110  to provide the desired predetermined length of each individual separator  26 , 28  with the web being severed in the nip between a rotary blade and the transfer cylinder. The tangential velocity or speed of the periphery of the transfer cylinder may be greater than the immediately upstream speed of the web when it engages with the cylinder to provide a gap or spacing  118  between adjacent individual separators received on the transfer cylinder. This may also maintain tension on the pasted web before it is severed. The cutter blades may be rotated by a variable speed motor  120  such as a stepper motor. 
     The individual separators  26 , 28  may be retained on the transfer cylinder  110  by a vacuum applied to a plurality of circumferentially and axially spaced apart ports  122  opening onto the periphery of the cylinder and underlying the individual separators. As the transfer cylinder rotates it may depose an individual pasted separator onto one of a series of substrates  20  by interrupting or stopping the vacuum applied to the ports preferably sequentially and if need be by applying preferably sequentially an atmospheric or superatmospheric pressure to the ports. Vacuum retaining and atmospheric or super atmospheric release pressure may be supplied to the ports through adjustable slip rings  124  communicating with generally axially extending passages  126  in the transfer cylinder communicating with the ports which open into the passages. If desired, after the vacuum ports have released and deposited an independent separator on a substrate they may be rotatably advanced to communicate with slip rings  128  supplying to them a super atmospheric pressure to clean them before they are further rotated to receive and retain another individual pasted separator severed from the web. 
     The substrates  20  may be advanced under the transfer cylinder  110  by a conveyor  130  which may include a continuous belt  132  with a run underlying the transfer cylinder and carrying thereon a series of equally spaced apart substrates  20 . This conveyor belt may be driven by a variable speed motor  134  such as a stepper motor to advance the substrates under the transfer cylinder at the same or substantially the same linear speed as the tangential peripheral speed of the pasted surface of the individual separators. Each separator  26 , 28  may be released from the transfer cylinder  110  and deposited on an underlying substrate  20  with its clearance holes  38  in registration with the substrate protuberances  34  and within the boundary of the edges  32  of such substrate. 
     Downstream of the transfer cylinder, if desired each substrate with a pasted separator received thereon may pass through the nip of cylindrical rotating rollers  72  and  74  to apply a force urging a separator onto its associated substrate. Desirably these rollers are driven by a variable speed stepper motor  136  at the same tangential speed of their nip as the linear speed at which the combined separator, paste and substrate is advanced through the rollers. 
     In operation of the production line  50 , the various variable speed motors such as stepper motors may be controlled by a suitable conventional electronic controller  140  (known to skilled persons) to synchronize their various speeds and phase relationship of operation. For example, the speed of a preferably stepper motor  98  driving the paster belt  92  may be set to provide the desired rate of production and used as the set point for the speed and synchronization of separate preferably stepper motors operating each of the paste hopper  100 , hole forming station punching  58  or rotary dies, rotating the transfer cylinder  110 , and driving the conveyor  130  advancing the substrates  20  relative to the transfer cylinder  110 . To provide the desired length of the individual separators  26 , 28 , the speed and synchronization of the preferably stepper motor  120  driving the cutter assembly (severing the web into individual separators) may also be varied and synchronized relative to the speed at which the transfer  110  cylinder is rotated. 
     The speed of the web feed rollers  78 , 80  may be varied and synchronized relative to the speed at which the paster belt  92  is advanced to maintain a slack loop  142  of the web between the feed rollers and the paster belt. This maintaining of the length or depth of the slack loop may be accomplished in various ways such as by synchronizing the speed of the feed rollers with the speed at which the belt  92  advances the web under the paste hopper  100  or more simply by sensors determining a minimum and maximum vertical depth of the slack loop  142  and providing signals to control the speed at which the feed rollers driven by the motor  82  advance the web to maintain the loop between the desired maximum and minimum depth of the slack loop. The speed or cycling of the hole forming station press  88  operating the punching dies  86  or the speed of the rotary cutting dies may be varied and synchronized with the speed at which the feed rollers  78 , 80  advance the web through the hole forming station  58 . The magnitude of the resistance to the unwinding rotation of the web roll produced by the air brake  84  may also be controlled relative to the extent to which the web is unwound and advanced by the feed rollers and if desired may be increased as the radius or diameter of the web roll  54  decreases as it is being unwound. 
     It is believed that this production line can make, paste and dispose on substrates at least 100 lineal feet per minute of pasted separators disposed on the substrates. This production line could also be configured to simultaneously run two separate parallel webs side by side to produce at least 200 lineal feet per minute of pasted separators disposed on substrates. 
     The forms of the invention herein disclosed constitute presently preferred embodiments and many other forms and embodiments are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.