Patent Publication Number: US-11646437-B2

Title: Electrochemical cells and methods of manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Patent Application No. 16/705,949, filed Dec. 6, 2019, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which is a continuation of U.S. patent application Ser. No. 15/724,701, filed Oct. 4, 2017, now U.S. Pat. No. 10,566,581, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which is a continuation of U.S. patent application Ser. No. 15/188,374, filed Jun. 21, 2016, now U.S. Pat. No. 9,812,674, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which is a continuation of U.S. patent application Ser. No. 14/543,489, filed Nov. 17, 2014, now U.S. Pat. No. 9,401,501, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which is a continuation of International Application Serial No. PCT/US2013/041537, filed May 17, 2013, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which is a continuation-in-part of and claims priority to U.S. patent application Ser. No. 13/832,836, filed Mar. 15, 2013, now U.S. Pat. No. 9,178,200, entitled “Electrochemical Cells and Methods of Manufacturing the Same,” which claims priority to and the benefit of U.S. Provisional Application No. 61/648,967, filed May 18, 2012, entitled “Simplified Battery Design,” each of which is hereby incorporated by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with government support under Grant Number DE-AR0000102 awarded by the Department of Energy. The government has certain rights in the invention. 
    
    
     BACKGROUND 
     Embodiments described herein relate generally to an apparatus for use within an electrochemical cell that can be used as both an outer casing and a current collector for the electrochemical cell and methods for making such apparatus. 
     Some known electrochemical cells (e.g., batteries) can include a variety of shapes and/or sizes, can be based on a wide variety of enabling materials and internal architectures, can be either passive or actively controlled, can be rechargeable or not, and/or can share certain common features that can allow them to convert chemical energy to electrical energy. Some known batteries can include a first electrode having a high electrochemical potential and a second electrode having a lower electrochemical potential relative to the first electrode. Each electrode can include an active material that participates in a chemical reaction and/or physico-chemical transformation during discharge by virtue of a favored thermodynamic change of material states, which can result in the flow of electrical current when a switch is closed. In some cases, for charge transfer to occur, two distinct conductive networks can allow the anode and cathode to be electrically connected. A separator can be used to provide isolation of the anode and cathode such that only ions are able to pass through it, and to prevent short circuiting. 
     The manufacture of battery electrodes can be a complex and capital intensive process, and can commonly include material mixing, casting, calendering, drying, slitting, and working (bending, rolling, etc.) according to the battery architecture being built. Because the electrode is manipulated during assembly, and to ensure conductive networks are in place, all components are compressed into a cohesive assembly, for example, by use of a binding agent. However, binding agents themselves occupy space, can add processing complexity, and can impede ionic and electronic conductivity. 
     Thus, there is a need for improvements in electrochemical cells (e.g., batteries) and the manufacture of electrochemical cells, such as eliminating components of the electrochemical cell and/or providing reduced packaging for the electrochemical cell, while maintaining the same energy storage capabilities. 
     SUMMARY 
     Electrochemical cells and methods of making electrochemical cells are described herein. In some embodiments, an apparatus includes a multi-layer sheet for encasing an electrode material of an electrochemical cell. The multi-layer sheet includes an outer layer, an intermediate layer that includes a conductive substrate, and an inner layer disposed on a portion of the conductive substrate. The intermediate layer being disposed between the outer layer and the inner layer. The inner layer defines an opening through which a conductive region of the intermediate layer is exposed such that the electrode material can be electrically connected to the conductive region and the intermediate layer can serve as a current collector for the electrochemical cell. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic illustration of a laminate sheet for encasing an electrochemical cell, according to an embodiment. 
         FIG.  2    is a cross-sectional view of the laminate sheet of  FIG.  1    taken along line  2 - 2  in  FIG.  1   . 
         FIG.  3    is a cross-sectional view of a portion an electrochemical cell, according to an embodiment. 
         FIG.  4    is a schematic top view of a portion of a laminate sheet for encasing an electrochemical cell, according to another embodiment. 
         FIG.  5    is a schematic top view of a portion of a laminate sheet for encasing an electrochemical cell, according to another embodiment. 
         FIG.  6    is a schematic top view of a portion of a laminate sheet for encasing an electrochemical cell, according to another embodiment. 
         FIG.  7    is a cross-section view of the portion of a laminate sheet of  FIG.  6    taken along line  7 - 7  in  FIG.  6   . 
         FIG.  8    is a cross-sectional view of a portion of an electrochemical cell, according to another embodiment. 
         FIG.  9    is a cross-sectional view of another portion of the electrochemical cell of  FIG.  8   . 
         FIG.  10    is a cross-sectional view of a portion of an electrochemical cell, according to another embodiment. 
         FIG.  11    is a cross-sectional view of a portion of an electrochemical cell, according to another embodiment. 
         FIG.  12    is a perspective view of a portion of an electrochemical cell, according to another embodiment. 
         FIG.  13 A  is a perspective view of a portion of an electrochemical cell, according to another embodiment. 
         FIGS.  13 B- 13 D  each illustrates a form angle for a laminate sheet for encasing an electrochemical cell, according to an embodiment. 
         FIGS.  13 E and  13 F  each illustrate a portion of a laminate sheet for encasing an electrochemical cell, according to an embodiment. 
         FIG.  14 A  is a perspective view of a portion of a laminate sheet for encasing an electrochemical cell, according to another embodiment. 
         FIG.  14 B  is a cross-sectional view of the laminate sheet of  FIG.  14 A  taken along line  14 B- 14 B in  FIG.  14 A . 
         FIG.  15 A  is a perspective view of a portion of a laminate sheet for encasing an electrochemical cell, according to another embodiment. 
         FIG.  15 B  is a cross-sectional view of the laminate sheet of  FIG.  15 A  taken along line  15 B- 15 B in  FIG.  15 A ; and  FIG.  15 C  is a cross-sectional view of the laminate sheet of  FIG.  15 A  taken along line  15 C- 15 C in  FIG.  15 A . 
         FIGS.  16 A- 16 C  illustrate steps of a process to manufacture an electrochemical cell, according to an embodiment. 
         FIG.  17 A  is a perspective view of an electrochemical cell, according to another embodiment. 
         FIG.  17 B  is a cross-section view of the electrochemical cell of  FIG.  17 A  taken along line  17 B- 17 B in  FIG.  17 A ; and  FIG.  17 C  is an enlarged view of a portion B of  FIG.  17 B . 
         FIG.  18 A  is an exploded perspective with of an electrochemical cell, according to another embodiment, with a portion of the electrochemical cell shown transparent. 
         FIG.  18 B  is an enlarged view of a portion of the electrochemical cell of  FIG.  18 A . 
         FIG.  18 C  is a perspective view of a portion of the electrochemical cell of  FIG.  18 A  shown assembled. 
     
    
    
     DETAILED DESCRIPTION 
     Electrochemical cells, such as batteries, and methods of manufacturing electrochemical cells are described herein in which the “pouch” or “casing” of the electrochemical cell (also referred to as “cell”) can also be used as an electrochemical functional component (e.g., the current collector) of the cell. As described herein, in some embodiments, a cell pouch (e.g., case) can include a laminated sheet formed with an outer layer, an intermediate metal foil layer and an inner layer. The inner layer can include openings to define a cavity in which an electrochemically active material of the electrode of the cell can be electrically connected with the metal foil member. Thus, in such an embodiment, the metal foil layer of the pouch can serve as the current collector of the cell. 
     In general, each electrode of an electrochemical cell can include active material(s), which can undergo chemical or physico-chemical change during discharge, and charge in the case of a secondary battery. The electrode can occupy/reside within a cavity of the electrochemical cell. The cavity can be defined as the volume of the cell that contains an electrode, and in some cases can contain additional volume to contain other components of the cell. Thus, in some embodiments, an electrode cavity can include several different regions. 
     For example, as described above, a cavity can refer to the entire volume of the cell in which an electrode is contained. In some embodiments, a cavity of a cell can include a fluid region, which can be the collective aggregated volume occupied by fluid suspension in the cavity, and which may or may not be continuous or homogeneous 
     A cavity can also include an active region. The active region can be the collection of fluid substance in which active materials are or would be active (i.e., undergoing chemical or physico-chemical change) during charge/discharge, which may vary with operating conditions (e.g., temperature, state of charge, current, among others), in electrical contact with both a current collector and a separator. 
     The cavity may have zero, one, two, or more ports or openings to facilitate fluid exchange, and the ports may reside on any surface defining the cavity including, for example, a side surface and/or a rear surface. The ports may permit insertion and retraction of special equipment used during manufacture of the cell, or as feedthroughs for instrumentation, for example, during manufacture of the cell, or remaining resident after manufacturing is completed. A portion of the area of a cavity can be bounded by a current collector, and at least some of the area of the cavity can be bounded by a separator. Other portions of the cavity can be bounded by for example, frame seals, port plugs, an electrolytic substance, containment hardware, intra-cavity mechanical supports, instrumentation/sensors, and/or fluids. 
     The cavity geometry can be, for example, polygonal (rectangular, hexagonal, etc.), have rounded edges, or other shapes depending on the design objective. The cavity depth/thickness may be uniform, or can vary according to a shape profile. The cavity may only include an active region, or be partitioned into active and inactive regions. The cavity volume may be interrupted by members spanning the volume (for example across the thickness) e.g., for structural, fluid dynamic, or other reasons. 
     Some embodiments described herein relate to the fabrication and/or methods of manufacturing electrochemical cells, where the electrodes of the cell can contain an active material(s), electrolytic substance(s), and optionally other materials such as, for example, material participating in conductive networks (e.g., carbon powder or salts), rheology modifiers (e.g. dispersants, fluid stabilizers, and other functional agents). This is distinguished from conventional batteries in that the active materials are mobile (e.g., flowable) in the electrolytic substance (i.e. are not fixed in position relative to one another—at least during manufacturing, and optionally also (i) through a post-assembly period where other processing steps are undertaken, (ii) through a conditioning period of the assembled battery, (iii) throughout a fraction of the battery life, (iv) for the entire battery life cycle, or (v) for discontinuous periods throughout the battery life). The term “during manufacturing” in this context means the period of time from the first introduction of electrode substance or a material component thereof into the cavity region of the battery until the last introduction of electrode substance or a material component thereof into the cavity region. In some embodiments, a method of manufacturing a cell can include sealing, tabbing, and an overall simplified fabrication process. 
     As used in this specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, the term “a port” is intended to mean a single port or a combination of ports. 
     Electrode formulations can include, for example, (1) active materials (i.e., the sources and sinks of ions and electrons), (2) carbon (or a mixture of carbons) or other material(s) having the primary, but not necessarily exclusive, function of electronic conduction, and (3) an electrolyte (e.g., a solvent or solvent mixture plus salt(s)) having the primary, but not necessarily exclusive function of ionic conduction. The electrode formulation may optionally include other additives having specific intended chemical, mechanical, electrical, and/or thermal functions. Electrode formulations can include, for example, the active materials, compositions, and/or semi-solid suspensions described in U.S. Provisional Application No. 61/787,382, entitled “[Semi-Solid Electrodes Having High Rate Capability,” and U.S. Provisional Application No. 61/787,372, entitled “Asymmetric Battery Having a Semi-Solid Cathode and High Energy Density Anode,” the entire disclosures of which are hereby incorporated by reference. 
     Electrodes of a conventional electrochemical cell are typically prepared by coating a metal foil substrate with a thin (e.g., about 100 μm to about 200 μm) wet slurry that is subsequently dried and calendered to a desired thickness. The slurry components in this method are typically active materials, conductive additives, a binding agent, and a solvent (e.g., commonly N-Methylpyrrolidone (NMP)). When the solvent is evaporated (in a drying oven covering the conveying line), the binder converts to a “glue” that holds all of the solid particles together in a matrix bound to the substrate. It is common for electrodes to be coated with the same materials on both sides of the substrate. As used herein, the term “electrode material” can refer to the slurry described above. 
     There are two common battery design approaches, (1) wound, and (2) stacked. In wound battery designs, electrode sheets can be cut to target dimensions, and then, with a separator placed in between, wound into a spiral or jelly-roll, then infiltrated with electrolyte and suitably packaged (typically in a cylindrical or rectangular metal can) to afford containment and electrical connections. In stacked battery designs, electrode sheets can also be cut to target dimension, but can then be stacked on top of one another with separators placed in between, forming a cell composed of physically discrete, rather than continuous in the case of wound cells, anode/cathode pairs. The stacked assembly can then be infiltrated with electrolyte and commonly packaged in either a pouch/bag, a plastic box, or a metal can, which can each also be referred to as a cell or battery casing as described herein. 
     In conventional pouch packaging, the pouch can perform several functions. One such function is to provide a hermetic isolation of battery materials from the environment. Thus, the pouch can serve to avoid leakage of hazardous materials such as electrolyte solvents and/or corrosive salts to the ambient environment, and can prevent water and/or oxygen infiltration into the cell. Other functions of the pouch can include, for example, compressive packaging of the internal layers, voltage isolation for safety and handling, and mechanical protection of the battery assembly. 
     Typical pouch materials can include laminates (e.g., multi-layer sheets), formed into, for example, two or three solid film-like layers and bound together by adhesive. The word “laminate” as used herein can also refer to layers of material that are not chemically adhered to one another. For example, the layers can be in areal contact with each other and coupled using other coupling methods, such as, for example, heat sealing, UV and/or adhesives (e.g., anaerobic adhesives). The inner layer can be, for example, a plastic layer, such as, for example, a polyolefin (e.g., a cast polypropylene (CPP) or polyethylene). The next or second layer can be a metal foil layer, such as, for example, aluminum, aluminum alloy, copper, nickel, titanium, stainless steel, gold, platinum or carbon. In some pouch configurations, there can be an additional layer(s). The additional layer can be, for example, a protective coating, formed with, for example, a plastic, such as nylon. The metal foil can provide the function of hermeticity, being much less permeable to certain compounds, especially water, than plastics. The inner plastic layer can be thermally bondable to itself, which is the convention regarding pouch closure and admission of electrical pass-throughs. In pouch closure, if the inner layers (e.g. CPP) of two pieces of pouch laminate are brought into physical contact, and heat is applied, the layers will melt and fuse, creating a robust seal if the processing conditions (e.g., power, temperature, duration) are chosen appropriately. For example, when the sealing is done in a closed loop, an interior volume can be formed that is isolated from the ambient or exterior environment. For electrical pass-throughs, electrical tabs (e.g., strips of conductive metal containing a ring-like wrapping of a select plastic, such as, for example, Surlyn) can be attached to the internal battery assembly (e.g., by ultrasonic weld, clamping fixture, tape, etc) with the plastic ring aligned in the pouch so as to be also thermally sealable. 
     The tabbing approach described above can add manufacturing complexity and cost, and may require careful control with respect to quality during manufacture. For example, a polymer material is often used around the area where the electrical tabs pass through from the inside to the outside to the pouch for a better seal and to avoid leaks. Failure to control this aspect adequately can result in increased costs. The pouch laminates described above are known in the battery industry for use as packaging material, but not as an electrochemically functional component of the battery. 
     Systems, devices, and methods are described herein related to an electrochemical cell having a casing or pouch that includes multi-layer laminate sheets that include at least a first or inner layer formed with a plastic material and a second layer formed with an electronically conducting material such that the multi-layer sheet can be used as an electrochemically functional element of the cell. For example, in some embodiments, the electronically conducting material (e.g., metal foil) of a pouch can be used as a current collector for the cell. In some embodiments, the metal foil can be used as a pass-through tab. Thus, the multi-layer or laminate sheet(s) of the cell pouch can be used as an electrochemically functional material of the cell, in addition to acting as a packaging material. 
       FIGS.  1 - 3    illustrate a portion of an electrochemical cell (also referred to herein as “energy storage device”), according to an embodiment. An electrochemical cell (e.g., a battery) can include a casing that includes two laminate or multi-layer sheets (also referred to herein as “laminate sheet” or “sheet”) coupled together to encase an electrode material of the cell. As shown in  FIGS.  1  and  2   , a casing  100  (also referred to as a “pouch”) can include a laminate sheet  110 . The laminate sheet  110  can include a first or inner layer  124 , a second or intermediate layer  122  and optionally a third or outer layer  120 . As shown in  FIG.  2   , the second layer  122  can be coupled to the third layer  120  and coupled to the first layer  124  with an adhesive  125 . In alternative embodiments, the third layer  120 , second layer  122  and first layer  124  can be coupled by other methods. For example, the third layer  120 , second layer  122 , and first layer  124  can be disposed in a stacked relation and then heat sealed, for example, around a periphery of the layers. In some embodiments, the first layer  124  and/or the third layer  120  can be molded onto the second layer. In some embodiments, the first layer  124  and/or the third layer  120  can be spread or coated onto the second layer. 
     The third layer  120  can be formed with, for example, a polyamide (e.g., Nylon) and can have a thickness, for example, of about 0.025 mm. The second layer  122  can be formed with an electronically conductive material, such as, for example, aluminum, an aluminum alloy, or copper, and can have a thickness, for example, between of about 0.025 mm and 0.040 mm. The first layer  124  can be formed with, for example, a material that is thermally bondable to itself. For example, the first layer  124  can be formed with a polypropylene (CPP). The first layer  124  can have a thickness of, for example, 0.040 mm. 
     In some embodiments, the first layer  124  can define one or more openings  126  such that a portion  142  of the second layer  122  is exposed through the opening  126 , as shown in  FIG.  1   . With the portion  142  of the second layer  122  exposed, an electrochemically active material of the electrode (also referred to as “electrode material”) can be in contact with and electrically connected to the second layer  122 , as described in more detail below. Thus, the second layer  122  can serve as the current collector for the cell. The opening(s)  126  can be formed, for example, by laser ablation, die cutting, or a cavity can be formed or molded into the first layer  124 . 
     As shown in  FIG.  3   , the casing  100  for an electrochemical cell can include two laminate sheets  110 ,  110 ′ coupled together, with for example, adhesive, heat sealing or other suitable coupling methods to form a hermetic seal. The laminate sheet  110 ′ shown in  FIG.  3    can be formed the same as or similar to the laminate sheet  110 . For example, the laminate sheet  110 ′ can include an inner layer  124 ′, an intermediate layer  122 ′ and an outer layer  120 ′ each coupled together with an adhesive  125 . A first electrode material (not shown) can be disposed on the exposed portion  142  of the second layer  122 , and a second electrode material (not shown) can be disposed on an exposed portion  142 ′ of the second layer  122 ′. For example, one of the cavities  126 ,  126 ′ can include an anode electrode and be referred to as the anode cavity of the cell, and the other cavity  126 ,  126 ′ can include a cathode electrode and be referred to as the cathode cavity of the cell. 
     A separator member  130  can be disposed between the laminate sheet  110  and the laminate sheet  110 ′ as shown in  FIG.  3   . The separator  130  can be used to provide isolation of the anode and cathode portions of the cell such that only ions are able to pass through it, and to prevent short circuiting of the cell. 
     In some embodiments, the inner layer  124  of the laminate sheet  110  and the inner layer  124 ′ of the laminate sheet  110 ′ can include a periphery portion (not shown in  FIG.  3   ) that extends beyond a periphery of the separator  130  such that the first layers  124 ,  124 ′ can be joined to form a seal. In some embodiments, the inner layers  124 ,  124 ′ are each formed with a material that is thermally bondable to itself (e.g., CPP as described above) such that when the two laminate sheets  110  and  110 ′ are joined, the first layer  124  and the first layer  124 ′ can be joined around their peripheries and thermally bond to each other to form a hermetic seal. 
     In some embodiments, the cell can include integrated electrical tabbing, which can obviate the need for (i) a discrete tab component (e.g., an electrical lead), (ii) connecting dedicated tabs to current collectors, and (iii) a dedicated tab sealing operation. Instead, as described herein, in some embodiments, an electrical tab or lead can be provided as an extension of the second layer (e.g., the current collector) of the laminate sheet (e.g.,  122  of the laminate sheet  110 ). Thus, electrical pass-through can be achieved via the cell sealing. 
       FIG.  4    illustrates a portion of a laminate sheet  210  that can be cut along the dashed lines to form three separate laminate sheets each for use within a casing of an electrochemical cell. As shown in  FIG.  4   , the laminate sheet  210  can include a first or inner layer  224 , a second or intermediate layer  222  and can optionally include a third or outer protective layer (not shown in  FIG.  3   ). As described above for laminate sheet  110 , the first layer  224  can be formed with a plastic material, such as, for example, a cast polypropylene, and can define one or more openings  226  to expose a portion  242  of the second layer  222 . The second layer  222  can be formed with an electrically conductive material that can be electrically coupled to an electrode material (not shown) disposed on the portion  242  through the opening  226  such that the exposed portion  242  of the second layer  222  can be used as a current collector for the cell. The first layer  224  can also define openings  236  that expose additional portions  232  of the second layer  222 . The exposed portions  232  of the second layer  222  can serve as a power connection tab and/or can be coupled to an electrical lead  234  that can be used to provide an electrical current to the cell, as shown in  FIG.  4   . For example, the electrical lead  234  can be welded, brazed, crimped, etc. onto the exposed portion  232 . 
     In alternative embodiments, rather than the exposed portion  232  being defined by an opening  236  of the first layer  224 , the exposed portion  232  can be integral with the exposed portion  242  of layer  232 . For example, in some such embodiments, the exposed portion  232  can extend from the exposed portion  242  as an integral component, and the electrode material can be disposed onto the exposed portion  242  while masking the exposed portion  232 . In some such embodiments, the electrode material can be spread onto the exposed portion  242  and exposed portion  232  and then the electrode material on exposed portion  232  can be scraped off or otherwise removed and the electrical lead  234  can be coupled to the exposed portion  232 . 
       FIG.  5    illustrates a laminate sheet  310  according to another embodiment. In this embodiment, the laminate sheet  310  can include a first or inner layer  324 , a second or intermediate layer  322  and a third or outer layer (not shown in  FIG.  3   ). The first layer  324  can be formed with a plastic material such as, for example, a cast polypropylene, and can define one or more openings  326  to expose a portion of the second layer  322 . As shown in  FIG.  5   , in this embodiment, there are three openings  326 . The second layer  322  can be formed with an electrically conductive material that can be electrically coupled to an electrode material (not shown) disposed on the exposed portions  342  of the second layer  322  through the openings  326 . In this embodiment, the second layer  322  includes an extended portion  327  that extends beyond a peripheral edge of the inner layer  324 . The extended portion  327  can function as a power connection tab to provide electrical current to the electrode material disposed on the exposed portion  342  of second layer  222 . 
       FIGS.  6  and  7    illustrate another embodiment of a laminate sheet that can be used within a casing for an electrochemical cell and can also be used as the current collector for the cell. A laminate sheet  410  includes a first layer  424  and a second layer  422 . The first layer  424  can be coupled to the second layer  422  with, for example, an adhesive, with heat sealing or other known coupling methods. The second layer  422  can be formed with an electrically conductive material such as, for example, an aluminum or copper material, and the first layer  424  can be formed with, for example, cast polypropylene (CPP) as described above for previous embodiments. In this embodiment, without a third or outer protective layer, it may be desirable for the second layer  422  to have a greater thickness than embodiments that have a third layer. For example, it may be desirable for the second layer  422  to have a thickness between about 0.075 and 0.100 mm. 
     The first layer  424  defines openings  426  such that portions  442  of the conductive second layer  422  are exposed through the openings  426 , as shown in  FIG.  6   . The exposed portions  442  of the second layer  422  can be electrically connected to an electrochemically active material of an electrode disposed on the second layer  422  within the openings  426 . Thus, the second layer  422  can serve as the current collector for the cell. As described above, the openings  426  can be formed, for example, by laser ablation or die cutting. 
     In some embodiments, a laminate sheet as described herein for use as a casing for an electrochemical cell and also as a current conductor for the cell can include a cavity or opening that is formed or molded into the laminate sheet. Such a cell having a formed laminate sheet(s) can be referred to as a “formed cell.” Such laminate sheets can be referred to as “formed laminate sheets.” Such formed laminate sheets can be formed such that at least a portion of the second layer (e.g., metal foil) is formed with a permanent deformation. The deformation can form a cavity within the laminate sheet in which an electrode material of the cell can be disposed. In some embodiments, an upper peripheral surface of the metal foil (e.g., second layer) on which an inner plastic layer is disposed may not be formed. In other words, an upper ledge can be maintained on which the inner layer can at least be disposed. In other embodiments, the inner layer can be disposed on at least a portion of a side wall of the formed cavity region. In some embodiments, the inner layer can be disposed on a portion of the lower surface defining the cavity region of the formed laminate sheet. 
     The wall and bottom surface of the formed cavity region of the laminate sheet can have relatively uniform thickness or the thickness can vary. The side wall can be formed at various angles relative to the bottom surface defining the cavity. For example, the angle can be formed with an angle between 0 and 90 degrees. In some embodiments, the angle can vary, for example, around a periphery of the cavity region. In some embodiments, the bottom surface of the cavity region can include raised portions, such as, for example, a dimpled surface, a wavy surface, a protrusion, ridges, etc. that can provide structural reinforcement to the laminate sheet. The cavity region can have a variety of different shapes and sizes. For example, the cavity region can be a polygonal shape (e.g., square, hexagonal, etc.), circular, elliptical or other suitable shapes. In some embodiments, a cell casing can include a first laminate sheet that is a formed laminate sheet and a second laminate sheet that is not formed. In other words, the other side of the cell casing can include an inner layer that defines openings that are, for example, die cut or laser formed, as described above for previous embodiments. 
       FIG.  8    illustrates a formed laminate sheet  510  that includes a first or inner layer, a second or intermediate layer and a third or outer layer (each not shown in  FIG.  8   ). As described above for previous embodiments, the second layer can include a metal foil formed with an electrically conductive material, such as, for example, aluminum, an aluminum alloy, or copper. The first layer can define one or more openings (not shown) to expose at least a portion of the second layer. The formed laminate sheet  510  defines a cavity  528  in which an electrode material can be disposed and be electrically connected to the exposed conductive material of the second layer (e.g., metal foil). In this embodiment, the laminate sheet  510  includes walls  540  that are formed at a substantially 90 degree angle relative to a bottom surface  542  of the cavity  528 . The bottom surface  542  can be the exposed surface of the second conductive layer. The walls  540  and bottom surface  542  define the cavity  528 . A separator  530  is coupled to the laminate sheet  510  and encloses the cavity  528 . The laminate sheet  510  can be coupled to a laminate sheet  510 ′ on an opposite side of the separator  530  to form a cell pouch or casing  500 , as shown in  FIG.  9   . The laminate sheet  510 ′ can be formed the same or similar as described for laminate sheet  510  and can define a cavity  528 ′. An anode electrode material can be disposed in none of the cavities  528 ,  528 ′ and a cathode electrode material can be disposed in the other of the cavities  528 ,  528 ′. 
       FIG.  10    illustrates a portion of a framed cell casing  600 . The cell casing  600  includes a laminate sheet  610  that includes a first layer  624  and a second layer  622 , and a separator  630  is coupled to the first layer  624 . A cavity  628  is defined by the side walls  640  of the first layer  624  and a surface  642  of the second layer  622 . As with previous embodiments, the second layer  622  can be formed with an electrically conductive material, such as, for example, aluminum, an aluminum alloy, or copper. An electrode material (not shown) can be disposed within the cavity  628  and be electrically connected to the exposed conductive material of the second layer  622  (e.g., metal foil), such that the second layer  622  can serve as the current collector for the cell. 
       FIG.  11    illustrates a portion of another framed cell casing  700 . The cell casing  700  includes a laminate sheet  710  that includes a first layer  724 , a second layer  722 , and a separator  730  is coupled to the first layer  724 . In this embodiment, a third layer  720  is also included. The third layer can be a plastic protective outer layer of the cell casing. A cavity  728  is defined by the side walls  740  of the first layer  724  and a surface  742  of the second layer  722 . As with previous embodiments, the second layer  722  can be formed with an electrically conductive material, such as, for example, aluminum, an aluminum alloy, or copper. An electrode material (not shown) can be disposed within the cavity  728  and be electrically connected to the exposed conductive material of the second layer  722  (e.g., metal foil). The second layer  722  also includes a tab portion  727  that extends beyond an outer perimeter of the inner layer  724 . The tab portion  727  can serve as a power connection tab to provide electrical current to the electrode. 
       FIG.  12    illustrates another embodiment of a formed cell casing for an electrochemical cell. A cell casing  900  includes a formed laminate sheet  910  that includes a first layer  924  and a second layer  922 . The laminate sheet  910  can also optionally include a third layer (not shown in  FIG.  12   ). As described above for previous embodiments, the second layer  922  can be formed with an electrically conductive material, such as, for example, aluminum or an aluminum alloy. The first layer  924  defines a first opening  926  to expose at least a portion  942  of the second layer  922 . The formed laminate sheet  910  defines a cavity  928  in which an electrode material can be disposed and be electrically connected to the exposed portion  942  of the second layer  922 . In this embodiment, the laminate sheet  910  includes walls  940  that are formed at a substantially 90 degree angle relative to a bottom surface  946  of the first layer  924 . The first layer  924  also defines the opening  926  at the periphery of the walls  940 . The walls  940  and bottom surface  946  together with the exposed portion  942  of second layer  922  define the cavity  928 . The first layer  924  also defines a second opening  936  that exposed a second portion  932  of the second layer  922 . The second exposed portion  932  can serve as a power connection tab and be coupled to an electrical lead  934  that can be used to provide electrical current to the cell. As described for previous embodiments, a separator (not shown) can be coupled to the first layer  924  and a second laminate sheet (not shown) can be coupled to the separator and to the laminate sheet  910  to form the cell casing  900 . 
       FIG.  13 A  illustrates a formed laminate sheet for a cell casing, according to another embodiment. A laminate sheet  1010  includes a first layer  1024  and a second layer  1022 . The laminate sheet  1010  can also optionally include a third layer (not shown in  FIG.  13 A ). As described above for previous embodiments, the second layer  1022  can be formed with an electrically conductive material, such as, for example, aluminum or an aluminum alloy. The first layer  1024  defines an opening  1026  to expose at least a surface portion  1042  of the second layer  1022 . The formed laminate sheet  1010  defines a cavity  1028  in which an electrode material can be disposed and be electrically connected to the exposed portion  1042  of the second layer  1022 . In this embodiment, the laminate sheet  1010  includes walls  1040  that are formed at a substantially 90 degree angle relative to the exposed surface portion  1042  of the second layer  1022 . The walls  1040  and surface portion  1042  of second layer  1022  define the cavity  1028 . In this embodiment, the second layer  1022  includes an extended portion  1027  that extends beyond an outer perimeter of the first layer  1024 . The extended portion  1027  can serve as a power connection tab to provide electrical current to the cell. As described for previous embodiments, a separator (not shown) can be coupled to the first layer  1024  and a second laminate sheet (not shown) can be coupled to the separator and to the laminate sheet  1010  to form a cell casing. 
       FIG.  13 B  is an enlarged view of a portion of the laminate sheet  1010  illustrating the formed angle of 90 degrees between the walls  1040  and the surface  1042 .  FIGS.  13 C and  13 D  each illustrate alternative embodiments of a laminate sheet  1010 A and  1010 B, respectively. As shown in  FIG.  13 C , the laminate sheet  1010 A can be formed with a 45 degree angle, and as shown in  FIG.  13 D , the laminate sheet  1010 B can be formed with a 30 degree angle.  FIGS.  13 E and  13 F  each illustrate alternative embodiments of a laminate sheet similar to laminate sheet  1010  with the first layer disposed on different portions of the second layer. In  FIG.  13 E , the laminate sheet  1010 C illustrates an embodiment with a first layer  1024 C extending onto a portion of the surface  1042 C of the second layer  1022 C. In  FIG.  13 F , the laminate sheet  1010 D illustrates an embodiment with a first layer  1024 D that does not cover the wall portions  1040 D of the second layer  1022 D. 
       FIGS.  14 A and  14 B  illustrate a formed laminate sheet for a cell casing, according to another embodiment that is similar to the embodiment of  FIG.  14 A . A laminate sheet  1110  includes a first layer  1124  and a second layer  1122 , and can also optionally include a third layer (not shown in  FIGS.  14 A and  14 B ). As described above for previous embodiments, the second layer  1122  can be formed with an electrically conductive material, such as, for example, aluminum, an aluminum alloy, or copper. The first layer  1124  defines an opening  1126  to expose at least a portion of a surface  1142  of the second layer  1122 . The formed laminate sheet  1110  defines a cavity  1128  in which an electrode material can be disposed and be electrically connected to the exposed surface portion  1142  of the second layer  1122 . The laminate sheet  1110  includes walls  1140  that are formed at a substantially 90 degree angle relative to the surface  1142  of the second layer  1122 . The walls  1140  and surface  1142  of second layer  1122  define the cavity  1128 . In this embodiment, the second layer  1122  also includes raised portions (e.g., protrusions, dimples, etc.)  1148  that provide structural reinforcement to the laminate sheet  1110 . 
     As with the embodiment of  FIG.  13 A , the second layer  1122  also includes an extended portion  1127  that extends beyond an outer perimeter of the first layer  1124 . The extended portion  1127  can serve as a power connection tab to provide electrical current to the cell. As described for previous embodiments, a separator (not shown) can be coupled to the first layer  1124  and a second laminate sheet (not shown) can be coupled to the separator and to the laminate sheet  1110  to form a cell casing. 
       FIGS.  15 A- 15 C  illustrate another embodiment of formed laminate sheet for a cell casing that includes structural reinforcement features. A laminate sheet  1210  includes a first layer  1224  and a second layer  1222 , and can also optionally include a third layer (not shown in  FIGS.  16 A- 16 C ). As described above for previous embodiments, the second layer  1222  can be formed with an electrically conductive material, such as, for example, aluminum, an aluminum alloy, or copper. The first layer  1224  defines an opening  1226  to expose at least a portion of a surface  1242  of the second layer  1222 . The formed laminate sheet  1210  defines a cavity  1228  in which an electrode material can be disposed and be electrically connected to the exposed portion of surface  1242  of the second layer  1222 . In this embodiment, the laminate sheet  1210  includes walls  1240  that are formed at an angle less than 90 degrees relative to the surface  1242  of the second layer  1222 , and the walls  1240  and surface  1242  of second layer  1222  define the cavity  1228 . In this embodiment, the second layer  1222  also includes raised portions  1248  (e.g., protrusions, dimples, etc.) and a raised portion  1250  that provide structural reinforcement to the laminate sheet  1210 . 
       FIGS.  16 A- 16 C  illustrate various steps in a process of manufacturing an electrochemical cell having a laminate casing that can also function as the current collector for the cell. As shown in  FIG.  16 A , at step  1 , a laminate sheet  1310  is placed within a die to form a cavity within the laminate sheet. The laminate sheet  1310  can include multiple layers as described above. For example, the laminate sheet  1310  includes a first layer  1324  that defines an opening through which a portion of a second layer  1322  is exposed. The laminate sheet  1310  can optionally include a third outer protective layer (not shown) as described herein. The second layer  1322  can be formed with an electrically conductive material and can be used as a current collector for the electrochemical cell. The second layer  1322  includes a power connection tab  1327  such as tabs  327  and  1027  described above. Step  2  illustrates the formed laminate sheet with a cavity  1328  defined therein in which an electrode can be disposed. At step  3 , a masking material can be placed over the first layer such that only the exposed portion of the second layer is visible through the masking. 
     As shown in  FIG.  16 B , at step  4 , an electrode (referred to as “slurry” in  FIG.  16 B ) can be placed on the exposed portion of the second layer. At steps  5  and  6 , the electrode can be smoothed or spread along the surface of the exposed portion of the second layer. For example, a blade or straight edged instrument can be used to spread the electrode. At step  7 , the masking can be removed leaving only the portion of the electrode that has been spread onto the exposed portion of the second layer. As shown in  FIG.  16 C , at step  8 , a separator can be placed on a portion of the first layer such that the separator is covering the electrode. At step  9 , the completed laminate sheet and separator of step  8  can be joined with another such completed laminate sheet. For example, the electrode of the laminate sheet of step  8  can be a cathode electrode and the other laminate sheet can include an anode electrode. At step  10 , a vacuum and heat seal process can be performed to seal the two laminate sheets together to form the finished cell as shown at step  11 . 
     In conventional batteries, anodes of different layers (e.g., in wound or stacked configurations) can be electrically connected in parallel to one another, and the same for cathodes, which can dictate that the same media (anodic or cathodic) be on both sides of a single metal foil layer. Such configurations are generally described using single letter abbreviations: ACCAACC . . . AAC or the like where A=anode layer and C=cathode layer. The repeating of letters for internal layers refers to double coating configurations. 
     For two layer laminates described above for previous embodiments (e.g., a plastic layer disposed partially on a metal foil layer), in some such embodiments, the cell can be referred to a as bipolar battery or bipolar cell.  FIG.  17 A  illustrates a bipolar cell  1452  that includes four electrochemical cells  1400 . In such a bipolar cell, the exposed metal foil layer of one cell  1400  (e.g., an anode-cathode pair) can be disposed adjacent to that of a neighboring cell  1400 , as shown in  FIG.  17 B . Electrical contact between adjacent foil layers can be realized by various methods, such as, for example, mechanical compression, use of an electrically conductive paste, welding, brazing, soldering, or other suitable technique. In such a bipolar stack, the stack voltage reflects the serial connection of all the cells composing it, and is thus substantially equal to the sum of the individual cell voltages. 
       FIGS.  18 A- 18 C  illustrate another embodiment of a formed cell casing for an electrochemical cell. A cell casing  1500  includes a formed laminate sheet  1510  and a formed laminate sheet  1510 ′. The laminate sheet  1510  includes a first layer  1524  coupled to a second layer  1522 , and the laminate sheet  1510 ′ includes a first layer  1524 ′ coupled to a second layer  1522 ′. The first layers  1524 ,  1524 ′ can be coupled to their respective second layers  1522 ,  1522 ′ with, for example, an adhesive (not shown). The first layers  1524 ,  1524 ′ can be formed with, for example, a cast polypropylene and the second layers  1522 ,  1522 ′ can be formed with, for example, an aluminum or copper material. In this embodiment, without having a third protective layer, the second layers  1522 ,  1522 ′ can be formed with a greater thickness, such as, for example, a thickness of 0.075 to 0.100 mm, and the first layer can have a thickness of for example, 0.040 mm. The first layer  1524 ′ and second layer  1522 ′ of the second laminate sheet  1510 ′ are shown transparent in  FIGS.  18 A- 18 C  for illustration purposes. As described above for previous embodiments, the second layers  1522 ,  1522 ′ can each be formed with an electrically conductive material, such as, for example, aluminum or an aluminum alloy, or copper. 
     The first layers  1524 ,  1524 ′ each define a cavity and an opening  1526 ,  1526 ′ that exposes a portion  1542 ,  1542 ′ of the respective second layers  1522 ,  1522 ′. The second layers  1522 ,  1522 ′ each include the exposed portion  1542 ,  1542 ′ that is exposed on both sides of first layer  1524 ,  1524 ′, and an extended portion  1527 ,  1527 ′ that is also exposed on both sides of first layer  1524 ,  1524 ′. The formed laminate sheet  1510  defines a cavity  1528  and the second laminate sheet  1510 ′ also defines a cavity (not shown). The cavity  1528  and the cavity of the second laminate sheet  1510 ′ collectively form an electrode cavity in which a stacked electrode  1554  can be disposed and be electrically connected to the exposed portion  1542  of second layer  1522  and the exposed portion  1542 ′ of the second layer  1522 ′. 
     The stacked electrode  1554  can be a conventional electrode that includes multiple electrodes each including an electrode material disposed on a metal foil sheet and a pair of electrical connection tabs  1556  and  1558 . The electrode stack  1554  can also include separators (not shown) disposed between the multiple electrodes. The tabs  1556  and  1558  can extend from the metal foil sheets and be welded to the laminate sheets  1510  and  1510 ′. As shown in  FIG.  18 C , the tab  1556  can be welded to the exposed portion  1527  of the laminate sheet  1510 , and the tab  1558  can be welded to the exposed portion  1527 ′ of the laminate sheet  1510 ′ as shown at weld location  1560 . In other words, as shown in  FIG.  18 C , the tab  1556  is welded on a bottom side to the top surface of the exposed portion  1527 , and the tab  1558  is welded on an upper side to a surface of the exposed portion  1527 ′. The greater thickness of the second layers  1522 ,  1522 ′ described above, can help facilitate welding of the tabs  1556  and  1558 . 
     The laminate sheet  1510  and the laminate sheet  1510 ′ can be coupled together with for example, a heat seal with the electrode stack  1554  disposed within the electrode cavity. With the tabs  1556  and  1558  weld to the exposed portions  1527  and  1527 ′, respectively, the second layers  1522  and  1522 ′ can serve as a power connection for the electrochemical cell  1500 . Thus, the need for a pass-through electrical tab is eliminated. 
     In some embodiments, the electrode material can be cast into the open cavity of the cell using conventional coating, drying, and calendaring processes. The coatings can be continuous or discrete to accommodate wound, prismatic, or other cell geometries. In other embodiments, the inner layer and foil layer, the foil layer and outer layer (in the case of a three layer), or both, may not be chemically bonded by adhesive, rather, they can simply be in physical contact. Adjacent layers of laminates can be sealed and contact between them established using mechanical means, e.g. compressive force imposed by exterior plates, tie rods, or bands. In other embodiments, the laminate may be used only on the end cells of a stacked assembly. In yet another embodiment, the laminate cell design and assembly approach can be used on one of the anode or cathode sides instead of both. 
     In another embodiment, the laminate can be fabricated using conventional processes. For example, the foil substrate layer can be coated with electrode materials in a conventional manner (e.g., coated, dried, calendered), and optionally in discrete patches. A framing material can then be applied to the foil substrate to create a laminate. In this example, the electrode is not a slurry-based electrode; rather the electrode can be a conventional electrode (e.g., cast active material and conductive additive in a solid matrix held together with a binding agent, interspersed with electrolyte within its pores). 
     In some embodiments, the laminate current collectors of a cell as described herein can be configured to perform a heat exchange function, i.e. they can also function as heat collectors and dissipaters. In some applications, it may be desirable to maintain the cell operating temperature within a specified range (for example, −40 C to 60 C, or −20 C to 55 C, or 0 C to 55 C, or 15 C to 30 C), and it may be desirable that heat generated during cell operation be collected and conducted away from the active area of the cell to other regions of the cell, which may be at any location outside of the active area, where the heat can be dissipated. Regions of the foil layer can act as (1) cooling fins in the ambient environment, which may be air, a conditioned (e.g., temperature, humidity, etc.) gaseous environment, liquid coolant (e.g., water, water/glycol mixture, heat exchange fluid, etc.) conductive, (2) thermally conductive pathways affixed by suitable methods (e.g., chemical joining such as, e.g., welding, brazing, soldering, or physical contact, such as, e.g., compressive contact, crimping, co-folding) to auxiliary thermal management hardware and systems, or (3) radiant surfaces. Heat conduction in the opposite direction is also possible, for example, to facilitate an operational start or a start sequence from a cold condition (e.g. −100 C, −60 C, −40 C, −20 C, &lt;0 C, or &lt;15 C) in which case the current collecting portion of the laminate is used to conduct heat into the cell from another heat source. 
     In some embodiments, electrochemical cells as described herein can be connected in series and packaged with an inert gas. For example, multiple cells can be stacked in series and then placed into a housing (e.g., a can). The interior volume of the housing can then be purged with an inert gas and then hermetically sealed. As described herein, the laminate sheet provides a first seal for individual cells and the outer housing provides a second seal from the environment (e.g. zero moisture environments). Furthermore, the inert gas improves safety of the cell, battery and/or module by reducing or preventing sparks and fires. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Where methods described above indicate certain events occurring in certain order, the ordering of certain events can be modified. Additionally, certain of the events can be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The embodiments described herein can include various combinations and/or sub-combinations of the functions, components and/or features of the different embodiments described. 
     Furthermore, while certain temperatures, pressures, and other measurements, calculations, and/or other values are described in approximate terms, the values used are not meant to be exact and a range of values can be used. For example, while the formed cell of  FIG.  8    is described as including 90 degree angles, in some embodiments, other angles can be used.