Abstract:
Method of making Li-intercalateable electrodes for a lithium-ion battery by applying a first film onto a first face of an electrically conductive grid, which film comprises a plurality of Li-intercalateable particles dispersed throughout a mixture of a polymeric binder and a plasticizer for the binder. Thereafter, a film-forming slurry having the same composition as the first film, plus a solvent therefor, is applied to a second face of the grid opposing the first face so as to provide a second film and such that the solvent in the slurry dissolves at least a portion of the first film and promotes solvent bonding of the films with the grid embedded therein. A polymeric backing film defining a separator is used as a manufacturing process aid, thereby eliminating the step of using a carrier film onto which the electrodes are fabricated and stripping off the carrier and discarding the same.

Description:
RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 09/862,388 filed May 21, 2001, which is copending, hereby incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field  
           [0003]    This invention relates to lithium ion batteries, and more particularly to a method of making electrodes (i.e., anodes and cathodes) therefor.  
           [0004]    2. Description of the Related Art  
           [0005]    Lithium ion batteries of the so-called “rocking chair” type are known in the art and comprise a lithium-intercalateable anode, a lithium-intercalateable cathode and a lithium-ion-conductive electrolyte sandwiched therebetween, as seen generally by reference to U.S. Pat. No. 5,196,279 to Tarascon. One particular variant of such battery is the so-called “lithium polymer” battery wherein (1) the electrodes (i.e. anode and cathode) contain lithium-intercalateable particles bound together in a porous polymer matrix, impregnated with electrolyte, and (2) a porous polymeric membrane/separator, impregnated with electrolyte, lies interjacent the electrodes.  
           [0006]    It is known to fabricate lithium-polymer cells by sandwiching a thin dry film of the separator/membrane material between a thin dry film of anode material and a thin dry film of cathode material and forming a laminate thereof by bonding the several films together under heat and pressure. Current collecting grids may be pressed into the anode and cathode materials at the same time or in a separate operation. However, this approach involves many steps, which increase fabrication cost and complexity. Moreover, achieving consistent and enduring lamination has been an ongoing problem in the manufacture of lithium polymer batteries. Delamination of one or more layers may result in an inoperative battery.  
           [0007]    Other approaches have been taken in the art. U.S. Pat. No. 5,296,318 to Gozdz et al. disclose a process for making a lithium polymer cell by a process wherein (1) a first electrode film is cast wet and dried on a first current collector defined by aluminum collector foil, (2) a separator/membrane film is cast wet and dried atop the first electrode film, (3) a second electrode film is cast wet and dried atop the separator/membrane, and (4) a second current collector applied to the second electrode film. However, the approach is not effective for mass production inasmuch as the process produces incomplete and/or unenduring contact between layers and components thereof. This is more particularly true for the above-mentioned lamination approach. The foregoing results in lower production efficiency, increased scrap rate (due to higher than acceptable resistances), and, accordingly, higher costs.  
           [0008]    In copending application Ser. No. 09/862,388, filed May 21, 2001, assigned to the common assignee of the present invention, a process is disclosed for fabricating composite electrodes that involves the use of a carrier layer upon which an electrode is formed. Copending application Ser. No. 09/862,388 further discloses, in one embodiment, that the carrier layer is stripped off to separate the electrode therefrom. It would be desirable to avoid having to strip off the carrier layer.  
           [0009]    There is therefore a need to provide an improved process for fabricating composite electrodes, including multilayer structures for use in lithium ion batteries or cells that minimizes or eliminates one or more of the problems as set forth above.  
         SUMMARY OF THE INVENTION  
         [0010]    Manufacturing complexity, cost, and scrap rate can be reduced, production rates increased, and better contact between the grid and the electrode material achieved by a process according to the present invention.  
           [0011]    The invention involves using a separator as a backing film in the coating process. Since the separator is used in cells and batteries, it can be retained, unlike the carrier disclosed in copending application Ser. No. 09/862,388, which is removed and discarded. This improvement allows attachment of the separator at an earlier stage in the overall process, and further, eliminates steps. In a preferred embodiment, the separator is a polymeric backing film. The separator performs its conventional function as well as a new function, namely, that of a carrier or backing film.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The present invention will now be described by way of example, with reference to the accompanying drawings, in which:  
         [0013]    [0013]FIG. 1 is a schematic of one embodiment of a process according to the present invention;  
         [0014]    [0014]FIG. 2 is a schematic of another embodiment of a process according to the present invention;  
         [0015]    [0015]FIG. 3 is a schematic of yet another embodiment of process according to the present invention;  
         [0016]    [0016]FIG. 4 is a schematic of still another embodiment of a process according to the present invention;  
         [0017]    [0017]FIG. 5 is a schematic of still yet another embodiment of a process according to the present invention; and  
         [0018]    [0018]FIG. 6 is a schematic of a lamination embodiment according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    [0019]FIG. 1 schematically depicts one embodiment of a continuous process for making lithium-intercalateable electrodes according to the present invention. Moving from left to right, a reel  2  dispenses a length of carrier strip  4  to a coating station  6 . The carrier strip  4  may comprise substantially any material which (1) does not stick firmly to the lithium-intercalateable, film-forming slurry to be subsequently applied thereto, and (2) has sufficient tensile strength to withstand being pulled through the system without deformation and sufficient rigidity to withstand the shrinkage forces form drying. Disposable smooth-faced material (e.g., Mylar) having a thickness between about 80 μm, and about 150 μm is particularly suitable for this purpose, as it is tough, inexpensive, and readily separable from the electrode. Alternatively, a reusable carrier strip, e.g., stainless steel, aluminum, plastic or the like, may be used in lieu of a disposable carrier strip. At the coating station  6 , the carrier strip  4  passes over a backing roller  8  while a thick, almost pasty, slurry of lithium-intercalateable, film-forming material is spread onto the strip  4  from a dispenser  10  to form a composite strip  11 . The dispenser  10  will preferably comprise a reservoir for retaining the film-forming slurry and have a narrow slotted die (not shown) at the mouth  12  thereof adjacent the strip  4 . Pressure applied to the film-forming slurry in the reservoir causes the slurry to flow out of the die onto the carrier strip  4  where it spreads as a ribbon-like first film  14  on the carrier  4 . A doctor blade or comma bar type device (not shown) may be used downstream of the dispenser  10  to spread and level the film  14  to a desired, controlled thickness. Other techniques, well know to those skilled in the art, for continuously forming thin films of material from slurries thereof may also be used.  
         [0020]    The slurry of electrode material (1) comprises a mixture of any suitable combination of the intercalateable particles, binders, plasticizers, solvents and conductive fillers mentioned above, or the like, (2) will have a viscosity that varies form about 1000 centipoise (cp) to about 13,000 cp, and (3) will be spread to a wet thickness varying between about 50 μm to about 1200 μm. Preferably, the material will have a viscosity of about 1000 cp to about 6000 cp and spread to a thickness varying between about 25 μm to about 700 μm when a slotted die, doctor blade, comma bar or other coating systems are used to spread the film onto the carrier  4 .  
         [0021]    In the case of the negative electrodes (i.e., the anode), the intercalateable particles comprise suitable carbons and graphites known to those skilled in the art. In some cases, conductive carbon may be added to the anode to enhance the electrical conductivity of the film. In the case of the positive electrode (i.e., the cathode), the lithium-intercalateable particles comprise any of a number of materials known to those skilled in the art including certain lithium-containing oxides of manganese, cobalt, nickel, aluminum, titanium, vanadium, and others and mixtures thereof. Conductive carbon is typically added to the cathode mix to enhance the electrical conductivity thereof.  
         [0022]    A variety of polymers may be used as the binder for the lithium-intercalateable particles provided that the binder is compatible with (e.g., will not degrade in) the operating environment of the battery. Known polymers for this purpose include certain polyolefins, fluorocarbons (e.g., polytetrafluoroethylene), polyvinylidene fluoride, EPDM, acrylates, urethanes and copolymers of the aforesaid. One binder is a copolymer comprising about 75% to about 92%, by weight, polyvinylidene fluoride (PVdF) and about 8% to about 25% hexafluoropropylene (HFP). Such binder is commercially available from the Atofina North America company under the trade name Kynar LBG or Kynar Power Flex. The binder is mixed with any of a variety of organic plasticizers, the selection of which will depend on the composition of the binder chosen. Suitable plasticizers for the aforesaid PVdF-HFP copolymer binder include propylene carbonate (PC), ethylene carbonate (EC), dibutyl phthalate (DBP), dimethyl phthalate, diethyl phthalate and tris butoxyethyl phosphate. The plasticizer will eventually be leached out of the film so as to leave a microporous polymer matrix, which is subsequently impregnated with electrolyte. In an alternate embodiment, plasticizer is omitted and the mix is cast, which leaves a microporous matrix on the film.  
         [0023]    The binder and plasticizer are dissolved in sufficient solvent to form a viscous/pasty slurry of solvent, binder, plasticizer and intercalateable particles. The choice of solvent will depend on the composition of the binder. For PVdF or PVdF:HFP copolymers, methyl ethyl ketone, dimethyl foramide, dimethyl acetamide, acetone or others (e.g., may be environmentally friendly) and combinations thereof are suitable, with acetone being preferred.  
         [0024]    The anode forming slurry may comprise, by weight, (1) about 20% to about 30% lithium-intercalateable graphite particles (i.e., ca. 1 μm to ca. 20 μm), (2) about 5% to about 10% binder (preferably PVd:HFP), (3) about 0.10% to about 14% plasticizer (preferably DBP, PC or others known in the art), (4) less than about 2% by weight conductive carbon particles, and (5) the balance solvent (preferably acetone). Preferably, an anode mix comprises, on a weight basis, about 25% carbon or graphite particles, about 6.8% 88:12 PVdF:HFP binder, about 8.9% dibutylphthalate (DBP) plasticizer, about 0.9% conductive carbon, and the balance acetone.  
         [0025]    The cathode forming slurry may comprise, by weight, (1) about 28% to about 35% LiNiCoO family particles as the lithium-intercalateable material, (2) about 4% to about 5% binder (preferably PVd:HFP), (3) about 0.1% to about 9% plasticizer (preferably DBP, PC or other), (4) about 2% to about 3% conductive carbon particles, and (5) the balance solvent (preferably acetone). Preferably, a cathode mix comprises, on a weight basis, about 34.7% Li 1+x MN 2 O 4  or LiNiCoAlO or LiCoO family particles (&lt;53 μm), about 4.4% PVdF:HFP binder, about 6.9% DBP plasticizer, about 2.5% conductive carbon, and the balance acetone.  
         [0026]    After the first film  14  is spread onto the carrier  4 , the composite strip  11 , thusly formed, passes through a drier  16  for removing the solvent from the binder/plasticizer. The drier  16  may take the form of a vacuum chamber, a forced air drier, a low temperature oven or combinations thereof for accelerating the evaporation of the solvent from the first film  14 . The drier  16  will preferably comprise an oven which also heats the first film  14  preparatory to having a current collecting grid  20  pressed thereinto downstream of the drier  16 . The drying temperature of the process ranges between about 20° F. to 130° F.; the tension of the strip between about 0.1 lbs. to 15 lbs.; and the speed at which the strip is moved between about 1 fpm to 15 fpm.  
         [0027]    Following drying of the first film  14 , the composite  11  advances to a station  18  where an electrically conductive grid  20  is pressed into the first film  14  by roller  22  as the composite  11  passes over roller  32 . The grid  20  will preferably comprise a thin (i.e., about 25 μm to about 75 μm) perforated or expanded metallic structure (i.e., Al for the positive electrode—cathodes, and Cu for the negative electrode—anodes) dispensed as a strip from a reel  24  therefor. An optional heating station  26  (shown in phantom) may be included to preheat the grid  20  prior to pressing it into the first film  14  at station  18 . The heating station may comprise an oven, and will preferably heat the grid to a temperature of about 75° F. to about 130° F. Optionally, the pressure roll  22  may be heated in addition to, or in lieu of, the grid  20  being preheated.  
         [0028]    After the grid  20  has been pressed into the first film  14 , a film-forming slurry  28  is spread atop the first film  14  and grid  20  form the dispenser  30  as the composite strip passes over the roller  32 . The composition of the slurry  28  (sans solvent) is the same as that of the dried first film  14 , and the solvent from the slurry  28  dissolves at least some of the dried first film  14  sufficiently to cause the two films to coalesce and bond together so as to provide an indistinguishable parting line therebetween. At the same time, the film material flows over and about the grid  20  providing intimate interfacial contact and enhanced electrical contact therebetween. Alternatively, the slurry for forming the second film  28  may use a different solvent than that used for the first film so long as it is a suitable solvent for the binders in both films  14  and  28 . After the second film  28  has been spread atop the first film  14 , and coalesced therewith, the composite strip  11  passes through a drier  34  for drying the strip by removing the solvent therefrom. Like drier  16 , the drier  34  may take the form of a vacuum chamber, a forced air dryer, a low temperature oven or combinations thereof and serves to accelerate evaporation of the solvent from electrode. The drier  34  will preferably comprise an oven, the temperature of which and residence time therein, is such as to slowly dry the composite  11  so as to avoid flash vaporization of the solvent within the films which can cause “blowholes” and macropores to form therein, as well as cause some localized separation of the electrode material from the grid.  
         [0029]    Following drying in the drier  34 , the composite  11  may optionally be calendered or squeezed between rollers (shown in phantom at a station  36 ) to (1) promote even better contact with the grid, (2) depress any errant intercalateable particles that might be projecting about the surface down into the film, and (3) press the films to a controlled final thickness and porosity. Calendering/rolling may be preformed at ambient or superambient temperatures (e.g., about 90° F. to about 140° F.) at pressures of about 5 to about 100 (preferably about 15 to 40) pounds per linear inch (pli).  
         [0030]    Following drying, and calendering/rolling at station  36  is done, the composite strip  11  may either (1) be fed directly to a cell assembly station where it is laminated with the separator/membrane and opposite polarity electrode, or (2) as shown in FIG. 1, will be coiled up on reel  38  for subsequent uncoiling and feeding to a cell assembly station at a later time. The temporary carrier  4  remains with the composite  11  during wind up and unwinding on/off the reel  38 , but is removed therefrom just prior to the electrode&#39;s being laminated to a separator/membrane and counterelectrode during the cell assembly operation (not shown). The temporary carrier  4  may also remain with the cathodes during the cell assembly operation (i.e., laminating of electrodes to separator) to keep the materials from sticking to the laminating equipment (e.g., rollers) and to control the dimensions of the film. Thereafter, the temporary carrier may be peeled off of the final laminate.  
         [0031]    [0031]FIG. 2 schematically depicts another embodiment of the invention using the same electrode slurries as described in connection with FIG. 1, but wherein a strip of grid material  40 , uncoiled from a reel  42 , is laid atop a strip of carrier material  44  uncoiled from a reel  46  as both pass over a roller  50 . A first film-forming slurry  47  of lithium-intercalateable material is dispensed onto the carrier  44  and grid  40  strip from a dispenser  48  (like that described about for FIG. 1) as it passes over the roller  50 . Thereafter, the thusly formed composite strip (i.e., carrier  44 , grid  40 , and film  47 ) passes in a first direction through a dryer  52  (i.e., like that described about for FIG. 1) to dry the film  47 . Subsequently, a second carrier strip  54 , (i.e., like the strip  44 ), is uncoiled from a reel  56  and laid atop the film  47  as it passes over roller  58 . Shortly thereafter, the first carrier strip  44  is peeled away from the composite strip at station  60  and wound up on reel  62  for disposal or reuse as appropriate to the particular carrier material being used.  
         [0032]    Following application of the second carrier material  54  to the composite strip, a second film  64  is dispensed atop the first film  47  and grid  40  as a slurry exiting from a dispenser  66  (like that described in FIG. 1) as the composite strip passes over the roller  68 . The composition of the second film  64  is the same as that of the first film  47 , and the solvent from slurry that forms the second film dissolves at least some of the dried first film  47  sufficiently to cause the two films to coalesce and bond together so as to provide an indistinguishable parting line therebetweeen, and in so doing encapsulate the grid  40  therein.  
         [0033]    After the second film  64  has been spread atop the first film  47  and grid  40 , the composite strip passes back through the drier  52  to finish drying the composite strip by evaporating and removing the solvent from the binder/plasticizer. Thereafter, the composite strip may optionally be calendered or rolled (shown in phantom at a station  70 ) as discussed above in connection with FIG. 1.  
         [0034]    Following drying in dryer  52 , and, if done, calendering/rolling, the composite strip may either be fed directly to a cell assembly station (not shown) where it is laminated with a separator/membrane and an opposite polarity counterelectrode, or, as shown in FIG. 2, will be coiled up on reel  72  for subsequent uncoiling and feeding to a cell assembly station at a later time.  
         [0035]    [0035]FIG. 3 schematically depicts still another embodiment of the invention using the same film-forming slurries as described above, but wherein a continuous belt (e.g., aluminum or stainless steel)  80  circulates around a pair of drums and  82  and  84  driven by conventional means (not shown). A backing table  86  underlies the uppermost/working portion of the belt and provides support therefor in the working region thereof where the electrode is formed. A first film-forming slurry  88  of lithium-intercalateable material is dispensed onto the belt  80  from a dispenser  90  having a slot at the mouth  92  thereof, like that described above in connection with FIGS. 1 and 2. The belt  80  carries the film-forming slurry  88  into a heated dryer  94  where evaporation of the solvent is accelerated, and the temperature of the film  88  is elevated (e.g., to about 50° C.). A strip of grid material  96  is fed into the dryer  94  prior to its being pressed into the warm film  88 . The grid strip  96  will preferably be preheated (heating means not shown) to about 110° F. to about 130° F. before entering the dryer  94 . A roller  98 , having a tangential velocity equal to the linear velocity of the belt  80 , presses the warm grid strip  96  into the warm film  88  as the belt  80  passes under the roller  98 . Optionally, the roller  98  may also be heated.  
         [0036]    After exiting from beneath the roller  98 , the composite strip  100  advances beneath a second dispenser  102  (like in FIGS. 1 and 2) that dispenses a second film-forming slurry  104  atop the composite strip  100 . From thence, the composite strip  100  advances into a dryer  106  for drying thereof of removing the remaining solvent therefrom. Thereafter, the composite strip  100  is ready for feeding directly into a cell assembly/laminating station, or for coiling up for storage and use at a later time.  
         [0037]    Optionally, a strip of carrier material  108  (e.g., Mylar), unwound from reel  110  (shown in phantom), may first be laid atop the belt  80  and either (1) stripped from the composite material  100  after it exits the dryer  106 , as shown in phantom at coil-up station  112 , when the composite strip is fed directly into a cell assembly station, or (2) wound up, in jelly roll fashion, with the composite strip  100  on a reel (not shown) for storage and subsequent use, at which time the carrier strip  108  is peeled away from the composite strip  100 . The carrier strip  108  serves not only to prevent the first film  88  from sticking to the belt, but for situation (2) immediately above, prevents the several turns of composite material  100  form sticking to each other in the jelly roll.  
         [0038]    Individual cathode, anode and separator layers may be laminated together to form a complete cell. The cathode and anode electrode layers have been described above. The polymeric separator/membrane for the cell effectively forms a microporous sponge (i.e., ca. 30%-70% porous) for retaining electrolyte between the electrodes, and is made in a manner much like the electrodes are made, but from a slurry comprising the same binder, plasticizer and solvent as is used for making the electrodes. Optionally certain inorganic fillers such as fumed silica, fumed alumina or silanized fumed silica or other fillers may be added in small quantities (e.g., &lt;about 7% by weight) to the organics to enhance the physical strength and melt viscosity of the separator/membrane and to increase the separator/membrane&#39;s ability to absorb electrolyte. One suitable separator/membrane mix comprises, on a weight basis, about 8.5% PVdF:HFP binder, 11.3% DBP plasticizer, and 73.3% acetone solvent. Other proportions of these materials are also known and useful. Like the electrode films, the membrane/separator films are made by spreading the slurry onto a suitable substrate, and driving off the solvent to dry the film.  
         [0039]    After the laminate has been formed, it is immersed in a suitable solvent (e.g., diethyl ether, alcohols such as methanol, hydrocarbons such as pentane, etc.), or through CO 2  extraction, which selectively (i.e., does not dissolve the binder) leaches the plasticizer out of the electrodes and separator/membrane so as to leave a network of micropores pervading the electrodes and separator/membrane. The micropores are subsequently backfilled/impregnated with the battery&#39;s electrolyte which comprises an organic solution of a dissociable lithium salt. Any of a variety of electrolyte solutions may be used including such lithium salts as LiClO 4 , LiN(CF 3 SO 2 ) 2 , LiBF 4 , LiCF 3 SO 3 , LiPF 6  or LiAsF 6 , dissolved in such organic solvents as dimethyl carbonate (DMC), ethylene carbonate (EC), diethoxyethane, diethyle carbonate, butylene carbonate and mixtures thereof. One such known electrolyte comprises about 0.5 to about 2 molar concentration of LiPF 6  in a mixed solvent comprising a mixture of ethylene carbonate and dimethyl carbonate. DP- 303 , 725  PATENT  
         [0040]    [0040]FIG. 4 schematically depicts another embodiment of the present invention. Unless stated to the contrary, the process to be described in connection with FIGS.  4 - 6  is the same as described and illustrated in connection with FIGS.  1 - 2 , except that a separator film is used in place of carrier  4 . The separator defines a backing film, preferably polymeric. FIG. 4 shows a reel  120  having a polymeric backing film  124  wound thereon, hereinafter sometimes referred to as separator  124 . In a preferred embodiment, separator  124  may comprise polyethylene material, polypropylene material, or a composite of both. Additionally, separator  124  is selected to have a thickness configured to match the thickness of the electrode formed thereon. In addition, separator  124  has a thickness selected to exhibit a strength suitable to be drawn through the various apparatus described and illustrated herein without mechanical failure or change in chemical properties, like carrier  4  in FIGS.  1 - 2 . It will be appreciated that the thickness may vary as a function of the actual composition selected, having due regard for the selection criteria described above.  
         [0041]    Separator  124  travels (i.e., is drawn towards) to a coating station  126 , optionally via intermediate rollers, such as a roller  122  (only one shown) or other conventional carrying apparatus. Coating station  126  comprises a backing roller  128  and a dispenser  130 . The separator  124  passes over backing roller  128  while a film-forming slurry  132  of lithium-intercalateable, film-forming material is spread onto the separator  124  from dispenser  132 . The composition of the slurry is the same as described in connection with FIG. 1, as is the dispensing and spreading steps. A composite strip  134  is formed having a separator/film. A predetermined interval (e.g., 3 seconds) after the slurry has been deposited, and while still wet, an electrically conductive grid, expanded metal, perforated metal foil or the like is “bed-in” or dispensed in the slurry.  
         [0042]    Thus, the composite strip  134  is advanced to a station where an electrically conductive grid  136  is disposed into the as yet still wet first film  132 . The grid  136  is dispensed from a reel/roller  138 . Roller  137  maintains tension in separator  124 , sufficient in nature, so that grid  136  seeks a position intermediate in the slurry. That is, there is (in thickness) about as much slurry about grid  136  as there is below. Grid  136  may be the same as grid  20  in FIG. 1.  
         [0043]    A composite strip  152  is thusly formed. Composite strip  152  includes separator/membrane strip  124 , a first film  132 , and grid  136 . The composite strip  152  then passes through a dryer  154  (i.e., like that described in connection with FIG. 1) to dry first film  132  (i.e., remove the solvent from the binder/plasticizer slurry). The dryer  154 , as well as the temperature ranges, drawing forces, and speed of movement may be the same as in FIG. 1. Significantly, the electrode is made by bedding in the grid while the slurry is still wet. This consolidation of individual steps, relative to the embodiment of FIG. 1, improves manufacturing speed and simplicity. Secondly, the separator  124  may be retained with the electrode just formed for later use (e.g, in producing a cell or bicell). This is also an improvement over the embodiment of FIG. 1, which uses a carrier film  4 , which is eventually stripped off and discarded.  
         [0044]    Thereafter, final composite strip  152  may be optionally calendered or rolled (see rollers  156  and  158 ) as discussed above in connection with FIG. 1. The electrode may be an anode or a cathode.  
         [0045]    [0045]FIG. 5 is the same as FIG. 4, except that a reel  140  having a carrier  142  is used in place of separator  124 . Carrier  142  may be the same as carrier  4 , and may further include P.E.T. or paper. A roller  144  allows transport to coating station  126 . A composite strip  148  is formed, which is the same as strip  152  except for the carrier/separator substitution mentioned above. In addition, the embodiment of FIG. 4 further includes a peeling station  60  and a reel  62  for peeling off carrier  142 . The remaining electrode  164  is wound up for later use.  
       EXAMPLE  
       [0046]    [0046]FIG. 6 shows the multi-layer fabrication process for a bicell. The process shown in FIG. 4 will be used to make two counter electrodes, for example, anodes, including a respective separator. The process shown in FIG. 5 will be used to fabricate a center electrode, such as a cathode, without a separator. FIG. 6 shows a first reel  160  having wound thereon a first strip having a first counter electrode corresponding in part to a first cell of the bicell, herein designated  152   a  (e.g., anode). FIG. 6 further shows a reel  162  having wound thereon a second strip having a second counter electrode corresponding in part to the second cell of the bicell, herein designated  152   b  (e.g., anode). Strips  152   a  and  152   b  may be that produced in the embodiment of FIG. 4 (i.e., including separator  124 ). FIG. 6 further shows a common or center electrode  164  of the bicell, which is shown wound on a reel. The common electrode may be an electrode produced according to the embodiment of FIG. 5. It should be appreciated that the embodiment shown in FIG. 6 is configured to produce a bicell  168  by laminating together the counter electrodes and the common electrode referred to above. However, bicell  168  according to the invention may be made using a continuous process similar to that shown and described in connection with the embodiment of FIG. 3.  
         [0047]    Common electrode  164  is dispensed from the winding wheel. Strip  152   a  is dispensed from reel  160  and is laminated on to common electrode  164  such that separator strip  124   a  is in contact with film  132  of common electrode  164 , forming an intermediate composite strip  166 . Composite strip  152   b  is dispensed from reel  162  in such an orientation that it is laminated to intermediate strip  166  so that separator  124   b  of strip  152   b  is also in contact with film  132  of common electrode  164 . Final composite strip  168  may be passed through a drier  170 , having temperature ranges, and residency times as set forth above in connection with the embodiment of FIG. 1. The final composite strip (bicell)  168  may optionally calendered or rolled (see roller/reel  172 ,  174  in FIG. 6).  
         [0048]    The final bicell laminate  168  may be immersed in a suitable solvent or through CO 2  extraction, which selectively leaches the plasticizer out of the electrodes and separator/membrane so as to leave a network of micropores pervading the electrodes and separator/membrane as discussed in more detail previously. The micropores may be subsequently backfilled/impregnated with the battery&#39;s electrolyte, as discussed in more detail previously. The bicell can be used to produce batteries, as known.  
         [0049]    While the invention has been disclosed in terms of specific embodiments thereof, it is not intended to be limited thereto, but rather only to the extent set forth hereafter in the claims which follow.