Abstract:
Systems and methods are disclosed for battery cells with positive polarity rigid containers. In accordance with disclosed embodiments, the cell may include a container and a lid piece that couple together to form a rectangular prismatic geometry. An electrode assembly having positive and negative coils may be disposed within the cell, and the positive coil may be conductively coupled to the cell. In this way, the cell (e.g., both the lid and the container) may be positively polarized. Further, the electrode assembly may incorporate a jelly-roll or a stacked structure. In one embodiment, the lid piece may include a vent that opens in response to pressure in the cell surpassing an established threshold. The lid may further include a positive terminal, negative terminal, and a method for filling the cell with electrolyte. Another embodiment may provide a battery module include multiple cells with positive polarity rigid containers.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from and the benefit of U.S. Provisional Application Ser. No. 61/555,298, entitled, “Prismatic Lithium Ion Cell with Positive Polarity Rigid Container,” filed Nov. 3, 2011, which is hereby incorporated by reference for all purposes. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates generally to the field of batteries and battery modules. More specifically, the present disclosure relates to battery cells with positive polarity rigid containers that may be used particularly in vehicular contexts, as well as other energy storage/expending applications. 
       BACKGROUND 
       [0003]    This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
         [0004]    Vehicles using electric power for all or a portion of their motive power may provide numerous advantages as compared to traditional vehicles powered by the reaction of gasoline within internal combustion engines. For example, vehicles using electric power may produce fewer pollutants and may exhibit greater fuel efficiency. In some cases, vehicles using electric power may eliminate the use of gasoline entirely and derive the entirety of their motive force from electric power. As technology continues to evolve, there is a need to provide improved power sources, particularly battery modules, for such vehicles. For example, it is desirable to increase the distance that such vehicles may travel without needing to recharge the batteries. It is also desirable to improve the performance and durability of the batteries, while reducing the cost associated with the battery modules. 
         [0005]    The technologically advanced use of battery modules and the desire to enhance performance of electric vehicles have given rise to new design and engineering challenges. For example, increased energy density may be desirable for such battery modules to increase vehicle travel distance per battery charge cycle. Currently, electric vehicles deriving the entirety of their motive force from electric power can only travel approximately 40-100 miles per charge. This short travel distance may prevent widespread public acceptance of such electric vehicles. Accordingly, it would be desirable to provide an improved battery module that exhibits improved energy density and durability while decreasing production costs. 
       SUMMARY 
       [0006]    A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
         [0007]    The present systems may be adapted to a wide range of settings and may be particularly well suited to vehicles deriving at least a portion of their motive force from electric power. Moreover, the systems may be useful in other applications, such as power storage for alternative energy sources, portable battery modules, and back-up power supplies. 
         [0008]    Embodiments of the present disclosure relate to battery cells with positive polarity rigid containers. In accordance with disclosed embodiments, the cell may include a container and a lid piece that couple together to form a rectangular prismatic geometry. An electrode assembly having positive and negative coils may be disposed within the cell, and the positive coil may be conductively coupled to the cell. In this way, the cell (e.g., both the lid and the container) may be positively polarized. Further, the electrode assembly may incorporate a jelly-roll or a stacked structure. In one embodiment, the lid piece may include a vent that opens in response to pressure in the cell surpassing an established threshold. The lid may further include a positive terminal, negative terminal, and a method for filling the cell with electrolyte. 
         [0009]    In another embodiment, a battery module may include multiple battery cells having the positive polarity rigid containers. Within the module, each cell may include a positive and a negative terminal arranged generally near one another. The positive polarization of the cells may enable each of the cells in the module to be arranged in the same orientation with respect to terminal placement. The module may incorporate intercellular connections, which operatively connect the cells to one another. In one embodiment, the intercellular connections may be shortened due to terminal placement and may be formed by stamping to reduce waste associated with manufacturing. 
         [0010]    Various refinements of the features noted above may exist in relation to the presently disclosed embodiments. Additional features may also be incorporated in these various embodiments as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more embodiments may be incorporated into other disclosed embodiments, either alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. 
     
    
     
       DRAWINGS 
         [0011]    Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
           [0012]      FIG. 1  is a perspective view of an embodiment of a vehicle having a battery module contributing all or a portion of the motive power for the vehicle; 
           [0013]      FIG. 2  illustrates a cutaway schematic view of an embodiment of the vehicle of  FIG. 1  provided in the form of a hybrid electric vehicle; 
           [0014]      FIG. 3  is a perspective view of an embodiment of a prismatic cell with a positive polarity rigid container; 
           [0015]      FIG. 4  is an exploded view of the embodiment of the prismatic cell of  FIG. 3 , having an electrode assembly; 
           [0016]      FIG. 5  is a perspective view of an embodiment of an electrode having a jelly-roll structure, which may be contained within a prismatic cell with a positive polarity rigid container; 
           [0017]      FIG. 6  is a cross-sectional view of the embodiment of the jelly-roll electrode taken along line  6 - 6  of  FIG. 5 , demonstrating the wound structure; 
           [0018]      FIG. 7  is a cross-sectional view of the embodiment of the jelly-roll electrode taken along line  7 - 7  of  FIG. 5 , showing the end coils; 
           [0019]      FIG. 8  is a perspective view of an embodiment of an electrode having a stacked structure, which may be contained within a prismatic cell with a positive polarity rigid container; 
           [0020]      FIG. 9  is a cross-sectional view of the embodiment of the stacked electrode taken along line  9 - 9  of  FIG. 8 , demonstrating the discrete plate structure; 
           [0021]      FIG. 10  is a cross-sectional view of the embodiment of the stacked electrode taken along line  10 - 10  of  FIG. 8 , showing the end coils; 
           [0022]      FIG. 11  is a block flow diagram describing the manufacturing and assembly process of a prismatic cell with a positive polarity rigid container; 
           [0023]      FIG. 12  is a perspective view of an alternative embodiment of a prismatic cell with a positive polarity rigid container, having the positive terminal proximate the negative terminal assembly; 
           [0024]      FIG. 12A  is a top view of the cell of  FIG. 12 , showing an embodiment of the placement of the positive terminal and the negative terminal assembly; 
           [0025]      FIG. 12B  is a top view of the cell of  FIG. 12 , showing an alternative embodiment of the placement of the positive terminal and negative terminal assembly; 
           [0026]      FIG. 13  is a perspective view of an embodiment of a battery module containing multiple prismatic cells of  FIG. 12 ; 
           [0027]      FIG. 14  is a plan view of an embodiment of a wind turbine using the pack configuration of  FIG. 13  for energy storage; and 
           [0028]      FIG. 15  is a plan view of an embodiment of a solar panel using the pack configuration of  FIG. 13  for energy storage. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The term “xEV” is defined herein to include all of the following vehicles, or any variations or combinations thereof, that use electric power for all or a portion of their vehicular motive force. As will be appreciated by those skilled in the art, hybrid electric vehicles (HEVs) combine an internal combustion engine propulsion system and a battery-powered electric propulsion system. The term HEV may include any variation of a hybrid electric vehicle, such as micro-hybrid and mild hybrid systems, which disable the internal combustion engine when the vehicle is idling and utilize a battery system to continue powering the air conditioning unit, radio, or other electronics, as well as to kick-start the engine when propulsion is desired. The mild hybrid system may apply some level of power assist to the internal combustion engine, whereas the micro-hybrid system may not supply power assist to the internal combustion engine. A plug-in electric vehicle (PEV) is any vehicle that can be charged from an external source of electricity, such as wall sockets, and the energy stored in the rechargeable battery packs drives or contributes to drive the wheels. PEVs are a subcategory of electric vehicles that include all-electric or battery electric vehicles (BEVs), plug-in hybrid vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engine vehicles. An electric vehicle (EV) is an all-electric vehicle that uses one or more motors powered by electric energy for its propulsion. 
         [0030]    As described in more detail below, disclosed herein are embodiments of prismatic lithium-ion cells with positive polarity rigid containers, which may be well suited to xEV applications. Embodiments of the prismatic cells provided herein may include a positively polarized container, which may be achieved through the coupling of the positive electrode coil to the container of the cell. Accordingly, the positive terminal may be located anywhere on the outer container of the cell, which enables a variety of improved configurations for battery modules. Additionally, the container may be sufficiently rigid, such that the inner elements of the cell may be protected. The cell may generally include a container (e.g., can) and lid piece that house a wound or stacked electrode, positive and negative current collectors, a positive terminal, and electrical insulation. The lid piece may contain positive and/or negative terminals, an integral vent, and a sealing device, such as a rivet. The positive polarity containers with prismatic geometry may provide several advantages when packaged as a battery module. 
         [0031]    The battery modules that include the prismatic lithium-ion cells with positive polarity rigid containers may be easily configured for use in xEVs. In certain embodiments, the xEV may include at least one battery module, and each battery module may include at least one prismatic lithium-ion cell configured to store and dispense electrical charge. The prismatic lithium-ion cell may have a positive polarity rigid container, which may offer advantages over traditional battery pack systems. For example, the prismatic cell may be arranged and constructed in such a way that improves the system level packaging efficiency, resulting in a higher energy density than lithium-ion cells of traditional systems. Further, the positive polarity containers may facilitate various packaging configurations of cells, resulting in improved battery modules to be used in xEVs and a variety of other applications. 
         [0032]    Turning now to the drawings,  FIG. 1  is a perspective view of a vehicle  20  in the form of an automobile (e.g., a car) having a battery module  22  for contributing all or a portion of the motive power for the vehicle  20 . The battery module  22  may be constructed from multiple individual prismatic cells. Although illustrated as a car in  FIG. 1 , the type of the vehicle  20  may be implementation-specific, and, accordingly, may differ in other embodiments, all of which are intended to fall within the scope of the present disclosure. For example, the vehicle  20  may be a truck, bus, industrial vehicle, motorcycle, recreational vehicle, boat, or any other type of vehicle that may benefit from the use of electric power for all or a portion of its propulsion power. For the purposes of the present disclosure, it should be noted that the battery modules and systems illustrated and described herein are particularly directed to providing and/or storing energy in xEVs, as was described in detail above. However, embodiments of the lithium-ion cells having positive polarity rigid containers may be utilized in other, non-vehicular applications as well. 
         [0033]    Further, although the battery module  22  is illustrated in  FIG. 1  as being positioned in the trunk or rear of the vehicle  20 , according to other embodiments, the location of the battery module  22  may differ. For example, the position of the battery module  22  may be selected based on the available space within the vehicle  20 , the desired weight balance of the vehicle  20 , the location of other components used with the battery module  22  (e.g., battery management modules, vents or cooling devices, etc.), and a variety of other implementation-specific considerations. 
         [0034]    For purposes of discussion, it may be helpful to discuss the battery module  22  with respect to a particular type of xEV, for example, an HEV.  FIG. 2  illustrates a cutaway schematic of the vehicle  20  provided in the form of an HEV. In the illustrated embodiment, the battery module  22  is provided toward the rear of the vehicle  20  proximate a fuel tank  24 . The fuel tank  24  supplies fuel to an internal combustion engine  26 , which is provided for the instances when the HEV utilizes gasoline power to propel the vehicle  20 . An electric motor  28 , a power split device  30 , and a generator  32  are also provided as part of the vehicle drive system. Such an HEV may be powered or driven by only the battery module  22 , by only the engine  26 , or by both the battery module  22  and the engine  26 . 
         [0035]    As previously noted, each battery module  22  is constructed from multiple individual cells (e.g., lithium ion). An embodiment of a single prismatic cell  40  is illustrated in  FIG. 3 . The rectangular prismatic cell  40  is generally composed of a container portion  42  and a lid piece  44 . As detailed below, both the container  42  and the lid piece  44  have features that enable the prismatic cell  40  to offer advantages for use in xEV applications, such as structural rigidity and positive polarization. 
         [0036]    The prismatic cell  40  assembly, including the container  42  and the lid  44 , is structurally rigid. To provide rigidity, the cell  40  may be formed from metallic materials, such as, aluminum or steel. For example, the rigidity of the cell  40  may enable the cell  40  to pass standard packaging industry tests, such as drop (ISO 2248), impact (ISO 2244), stacking (ISO 2234), and/or compression (ISO 12048) tests. The rigidity of the cell  40  may enable multiple cells  40  to be tightly packed within the battery module  22  to reduce the overall volume occupied by the battery module  22 . Further, the rigidity of the prismatic cell  40  may improve the durability of the cell  40  by preventing punctures and other minor deformations of the cell  40 , thereby improving the abuse tolerance of the cell  40 . 
         [0037]    The container  42  includes vertical sides  46  (e.g., front, back, left, and right) and a bottom  48  of the cell  40 . The geometry of the container  42  is such that opposite vertical sides  46  (e.g., front and back/right and left) are generally parallel. Accordingly, the bottom  48  is generally perpendicular to the vertical sides  46 . The top of the container  42  remains open, leaving an opening  50 . The opening  50  of the container  42  accepts the lid piece  44 , which may be constructed separately from the container  42 . The container  42  and the lid piece  44  may be coupled (e.g., crimped, welded, etc.) to form a rectangular prism, resulting in the prismatic shape of the cell  40 . 
         [0038]    The lid piece  44  may integrally include a vent  52 . The integral vent  52  may provide a pressure relief feature, while also simplifying the manufacturing process associated with the lid piece  44 . In the event that pressure builds within the cell  40 , the vent  52  may act as a release valve and may partially disengage (e.g., remains attached by a tab) from the lid piece  44  to release the pressure. The integral vent  52  may also simplify manufacturing and assembly procedures for constructing the cell  40 . For example, the vent  52  may be scored, formed, cut, coined, or otherwise machined into the lid piece  44  at the same time as the lid piece  44  is stamped, thereby requiring only one manufacturing step and reducing associated manufacturing costs. Further, including the pressure release in the form of the integral vent  52  means that internal pressure release components may not be used, which may result in a smaller, more compact cell, or leave more space available to increase the amount of energetic material within the cell  40 . It should be noted that the vent  52  may have a different geometry and is not limited to the placement on the lid piece  44  shown in  FIG. 3 . For example, the vent  52  may be circular, rectangular, or any other suitable shape. 
         [0039]    As shown in  FIG. 3 , the lid piece  44  may include additional components. In the depicted embodiment, a terminal hole  54  is located at an end of the lid piece  44 . The terminal hole  54  houses a negative terminal assembly  56 . Additionally, the lid piece  44  may include a rivet hole  60  to hold a rivet  62 . Once the cell  40  has been assembled (all internal components enclosed within the container  42  and lid piece  44 ), the rivet  62  may be coupled to the rivet hole  60  to seal the cell  40 . The rivet  62 , once placed in the rivet hole  60 , may be fixed tightly enough that in case of pressure build-up the vent  52  would disengage prior to the rivet  62 . Although a rivet hole  60  and rivet  62  assembly is described according to this embodiment, other embodiments may replace the rivet  62  with a ball bearing, a welded plug, a crimped tube, or any other suitable sealing method. 
         [0040]    To provide a better understanding of the internal arrangement of the cell  40 ,  FIG. 4  provides an exploded view of an embodiment of the cell  40  demonstrating the internal components. As the lid piece  44  is positively polarized, the negative terminal assembly  56  must be isolated from the body of the cell  40  to prevent a short circuit. An exploded view of the negative terminal assembly  56  is included in detail to demonstrate the manner in which it may be electrically insulated from the positively polarized lid piece  44 . The negative terminal assembly  56  has a tab  70  as the base, with a bottom gasket  72  placed around the tab  70 . The tab  70  with the bottom gasket  72  is placed through the negative terminal hole  54  such that the top surface of the bottom gasket  72  is in contact with the bottom surface of the lid piece  44 . A top gasket  74  is placed around the tab  70  such that the bottom surface of the top gasket  74  is in contact with the top surface of the lid piece  44 . A metal washer  76  is layered on top of the top gasket  74 . The gaskets  72  and  74  may be formed of a polymer material to provide electrical insulation and sealing around the negative terminal hole  54 . The arrangement of the gaskets  72  and  74  isolates the negative terminal assembly  56  from the lid piece  44 . The tab  70  and metal washer  76  are used to transfer charge from the negative terminal assembly  56 , for example, to the positive terminal  58  via a cord, wire, cable, etc. 
         [0041]    To provide charge to the negative and positive terminals  56  and  58 , current collectors  78  and  80  couple the terminals  56  and  58  to an electrode assembly  82 . The negative terminal assembly  56  is coupled to a negative current collector  78 , and the positive terminal  58  is coupled to a positive current collector  80 . The current collectors  78  and  80  may be designed to reduce the volume occupied by the current collectors  78  and  80  within the cell  40 . The reduced design may enable more internal volume to be dedicated to an electrode assembly  82 , thereby increasing the total energy density of the cell  40 . For example, the current collectors  78  and  80  may be ultrasonically welded to the electrode assembly  82  to save space. Ultrasonic welding may be desired as no additional filler material/apparatus is required, thereby minimizing occupied volume within the cell  40 . 
         [0042]    The electrode assembly  82  provides the energy within the cell  40 . To maximize the energy density of the cell  40 , the electrode assembly  82  should account for as much of the internal volume of the cell  40  as possible. To sufficiently utilize the large portion of internal volume of the cell  40  occupied by the electrode assembly  82 , the electrode assembly  82  may be a jelly-roll (e.g., wound) or a stacked configuration. Both jelly-roll and stacked electrode configurations enable large electrode surface area while minimizing internal resistance within the cell  40 . Enabling further design optimization, both jelly-roll and stacked electrode configurations can be oriented vertically (e.g., coils  84  and  86  extending to the top and bottom) or horizontally (e.g., coils  84  and  86  extending to the right and left) within the cell  40 . 
         [0043]    The electrode assembly  82  includes a positive coil  84  extending from one end and a negative coil  86  extending from the opposite end. The positive coil  84  may be constructed of aluminum, while the negative coil  86  may be constructed of copper. The positive coil  84  provides a positive charge to the positive terminal  58  via the positive current collector  80 . Similarly, the negative coil  86  provides a negative charge to the tab  70  of the negative terminal assembly  56  via the negative current collector  78 . Thus, the coils  84  and  86  of the electrode assembly  82  generate an electric potential across the terminals  56  and  58 . 
         [0044]    The positive coil  84  provides charge to the container  42  to positively polarize the container  42  and the lid piece  44 , thereby enabling the positive terminal  58  to be placed anywhere on the outside of the cell  40 . To achieve this, the positive coil  84  of the electrode assembly  82  may be ultrasonically welded to the positive current collector  80 , which is then placed in direct contact with the container  42  and/or the lid piece  44 . As the entire cell  40  is positively charged, the positive terminal may be located anywhere on the cell  40 , enabling improved battery module  22  configurations. Further, improved thermal management of the cell  40  may be possible utilizing the positive polarity of the cell  40 . For example, heat generated within the cell  40  may be conducted away from the electrode assembly  82  to the container  42  via the positive current collector  80 . The excess heat may be subsequently removed from the container  42  by an external heat management system. 
         [0045]    To ensure the operability of the cell  40  and prevent the occurrence of a short circuit, the negative charge generated by the negative coil  86  of the electrode assembly  82  is electrically isolated from the container  42 . An insulation film  88  may be placed around the body of the electrode assembly  82  to prevent contact between the electrode assembly  82  and the container  42 . Further, an insulation cap  90  may be placed over the body of the negative current collector  78  to prevent any negative charge contacting the positively polarized container  42 . The insulation film  88  and cap  90  may be composed of any suitable electrically insulating material, such as, glass, paper, polymers, plastics, and/or a combination thereof. The insulation film  88  and cap  90  may be constructed to have minimal thickness, such that the electrode assembly  82  may maximize the amount of space it occupies within the cell  40 . 
         [0046]    As the electrode assembly  82  is the only component of the cell  40  that contains energy, the geometry of the electrode assembly  82  may be optimized to utilize the internal volume of the cell  40  more effectively.  FIG. 5  illustrates an embodiment of the electrode assembly  82  wherein the electrode assembly  82  is a jelly-roll  100 . In the depicted embodiment, the electrode assembly  82  is assembled from four layers of long, thin, flat materials simultaneously wound to result in a flattened cylindrically shaped coil, thus gaining the designation “jelly-roll.” The perspective view of  FIG. 5  demonstrates the jelly-roll  100  with the positive coil  84 , the negative coil  86 , and an outer layer of an insulation material  102 . 
         [0047]    To aid in the discussion of the layered structure of the jelly-roll  100 ,  FIG. 6  depicts a cross-section view of the jelly-roll  100 . The four long flat layers are arranged in a compacted form via winding and may be wound with or without the use of a core  108 . The electrical insulation material  102  accounts for two of the layers. A negative coil material  104  accounts for one layer, and a positive coil material  106  accounts for the final layer. When wound as in  FIG. 6 , the insulation material  102  is positioned on the outside, followed by the negative coil material  104 , another layer of insulation material  102 , and a final layer of positive coil material  106 . As shown, this results in alternating layers of coil materials  104  and  106  and insulation material  102  when wound. Positioning a layer of insulation material  102  between each layer of negative coil material  104  and positive coil material  106  prevents contact between the coil materials  104  and  106 , resultantly preventing short circuits within the jelly-roll  100 . 
         [0048]    When viewed from a longitudinal cross-section, as in  FIG. 7 , the different widths of the layers of the electrode assembly  82  are depicted. The layers of electrical insulation material  102  may be centered with respect to the jelly-roll  100 . The layers of the negative coil material  104  may extend beyond the insulation material  102  to the left to form the negative coil  86 , while the layers of the positive coil material  106  may extend beyond the insulation material  102  to the right to form the positive coil  84 . However, in alternative embodiments, the coil materials  104  and  106  may extend different lengths and/or directions to form the coils  84  and  86 . Further, the actual number of layers or windings applied to the jelly-roll  100  may vary to create different coil configurations in an actual implementation. 
         [0049]    As an alternative to the jelly-roll  100 , the electrode assembly  82  may be in the form of a stack  120 , as shown in  FIG. 8 . Within the stack  120 , the positive coil  84  may be formed of discrete plates formed of the positive coil material  106 . Similarly, the negative coil  86  may be formed of discrete plates formed of the negative coil material  104 . The electrical insulation material  102  may be a continuous strip that alternatingly weaves between the plates of negative and positive coil materials  104  and  106  to prevent a short circuit, as shown in  FIG. 9  (taken along line  9 - 9  of  FIG. 8 ). Appropriate insulation materials  102  may include paper, glass, plastic, or a combination thereof. 
         [0050]    The cross-section of the electrode stack  120  shown  FIG. 10 , taken along line  10 - 10  of  FIG. 8 , depicts the different widths of the coil materials  104  and  106  which form the electrode coils  84  and  86 . The arrangement of  FIG. 10  is similar to that of  FIG. 7 , demonstrating alternating coil materials  104  and  106  separated by the electrical insulation material  102  to prevent short circuits between the coil materials  104  and  106 . To form the negative coil  86 , the plates of the negative coil material  104  may extend to the left, beyond the edge of the insulation material  102 . To form the positive coil  84 , the plates of the positive coil material  106  may extend to the right, beyond the edge of the insulation material  102 . A varying number of layers may be applied to the stacked electrode  120  in an actual implementation. 
         [0051]    Although either electrode  82  configuration, jelly-roll  100  or stack  120 , may be functional within the cell  40 , one configuration may be selected depending on the specific goals of the implementation. For example, the jelly-roll  100  may be desirable when maximizing the energy density of the cell  40  is the primary goal. Alternatively, the stack  120  may be desirable when minimizing the cost of the cell  40  is the primary goal. Both configurations may generally enable efficient energy packing in the cell  40 , which may provide an extended travel range for xEVs. 
         [0052]    The method of assembly and manufacture of the cell  40  may provide an additional approach to improve the energy density and decrease the cost associated with battery modules  22  for xEVs.  FIG. 11  illustrates a general method  122  for the construction of a prismatic lithium-ion cell  40  with a rigid positive polarity container  42 . The insulation material  102  and coil materials  104  and  106  may be selected based on desired battery chemistry. For example, the insulation material may be paper, the negative coil material  104  may be copper, and the positive coil material  106  may be aluminum. Selection of thin materials may enable more layers to be formed within the electrode assembly  82 , increasing the energy density of the cell  40 . Further, the coil materials  104  and  106  may be coated, leaving only the ends exposed to form the positive coil  84  and the negative coil  86  (block  124 ). Depending on the chosen geometry, jelly-roll  100  or stack  120 , the electrode assembly  82  may be formed (block  126 ). The electrode assembly  82  may be prepared before, after, or during the preparation of the rest of the cell  40 . 
         [0053]    The construction of the cell  40  includes the manufacture of the container  42  and lid piece  44 . The lid piece  44  may be stamped from a sheet of steel or aluminum. The container  42  may be formed by extrusion, welded fabrication, brazed fabrication, casting, another method, or a combination thereof from steel or aluminum (block  128 ). The lid piece  44  may contain two holes: the negative terminal hole  54  and the rivet hole  60 , which may formed by a punching process (block  130 ). Both holes may be punched simultaneously, or each hole may be punched independently. Additionally, the vent  52  may be scored, formed, cut, coined, or otherwise machined into the lid piece  44  (block  132 ). To save time and cost associated with manufacturing, the steps contained in blocks  128 ,  130 , and  132  (with respect to lid piece  44 ) may be performed simultaneously. The assembly process for the internal components of the cell  40  may also be simplified to reduce the cost and time expended. 
         [0054]    To maximize the energy density, the volume allotted to connector material/apparatus for assembling internal components of the cell  40  may be minimized, particularly with respect to minimizing and/or eliminating the use of welding. The positive terminal  58  may be welded to the container  42  or the lid piece  44 , depending on the desired battery module  22  arrangement (block  134 ). The welding process used may be modified to limit the amount of filler material required. The polymeric properties of the gaskets  72  and  74  may be utilized to form a swaged connection and seal between the lid piece  44  and the negative terminal assembly  56  (block  136 ), thereby removing the need to weld the negative terminal assembly  56  to the lid piece  44 . The swage connection may be an advantageous method of assembly since it does not use any additional components/material, thereby preserving volume within in the cell  40  for the electrode assembly  82 . Also in an effort to preserve cell  40  internal volume, the current collectors  78  and  80  may have a reduced design. To further this effort, the current collectors  78  and  80  may be ultrasonically welded to the terminals  56  and  58 , respectively (block  138 ). Ultrasonic welding may be beneficial since the process does not use a filler material to couple components. Rather, the components are coupled using high-frequency acoustic vibrations to create a solid-state weld. Ultrasonic welding may also be utilized to couple the current collectors  78  and  80  to the coils  86  and  84 , respectively (block  140 ). Alternatively, another advanced welding process, such as laser welding, may be used. 
         [0055]    Once the internal components are assembled, they may be placed within the cell  40  to complete the method of assembly  122 . The electrode assembly  82  may be wrapped in a thin insulation film  88  to prevent electrical contact between the electrode assembly  82  and the container  42 . As the container  42  is positively polarized, further separation may be desirable between the negative coil  86  and the container  42 . Therefore, the additional insulation cap  90  may be installed over the negative coil  86  (block  142 ). Use of thin insulation materials, such as, plastic, rubber, or paper, may enable increased energy density of the cell  40  by reducing the internal volume consumed by insulation. After the insulation film  88  and cap  90  are in place, the entire resultant assembly (e.g., insulated electrode assembly  82 , current collectors  78  and  80 , and terminals  56  and  58  coupled to the lid piece  44 ) may be placed into the container  42  via opening  50  (block  144 ). The lid piece  44  may then be coupled (e.g., crimped, welded, etc.) to the container opening  50  (block  146 ). The cell may be filled with an electrolyte material (e.g., liquid or gel) via the rivet hole  60  (block  148 ). The cell  40  may be formed (block  150 ), and finally, the cell  40  may be sealed (e.g., by fixing the rivet  62  in the rivet hole  60 ) (block  152 ). The fully assembled cell  40  may then be ready for use, for example, in a battery module  22  for use in an xEV, a portable battery module, or another energy storage application. Method  122  may include some additional steps during an actual implementation. Further, the steps of the method  122  may be performed sequentially as outlined, or the steps may be re-ordered, as per design requirements. 
         [0056]    The prismatic cell  40  with the rigid positively polarized container  42 , as manufactured and assembled with respect to method  122 , may be well-suited for integration into a battery module  22 . Particularly, the cell  40  as depicted in  FIG. 12  may be well-suited for configuration into a battery module  22  for an xEV. A primary feature of the positively polarized cell  40  is that the positive terminal  58  may be located anywhere on the cell  40 . Accordingly, in  FIG. 12 , an embodiment of the cell  40  is shown wherein the positive terminal  58  has been relocated (with respect to  FIG. 3 ) to be relatively near the negative terminal assembly  56 . For example,  FIG. 12A  provides a top view of the cell  40  in which a line  160  bisects a length  162  of the lid piece  44 . In the depicted embodiment, the positive terminal  58  may be considered to be near the negative terminal assembly  56  when both terminals  56  and  58  are located on the same side of the bisecting line  160 . Alternatively, as presented in  FIG. 12B , the positive terminal  58  and the negative terminal assembly  56  may be separated by a distance  164 . In this embodiment, the positive terminal  58  may be considered to be near the negative terminal assembly  56  when the distance  164  is a small percentage of the length  162 . For example, the distance  164  may be between approximately 5% and 40% of the length  162  of the cell  40 . Placement of the positive terminal  58  near the negative terminal assembly  56  may provide several advantages when used as part of the battery module  22 . 
         [0057]    Further, the rectangular prismatic shape of the cell  40  may enable improved battery module  22  arrangements. For example, as opposed to a module of cylindrical cells, less volume is required to house a module of the prismatic cells  40  due to less airspace between the cells  40 . This may be useful in xEV applications, as well as other energy storage applications, where free space is limited.  FIG. 13  depicts an embodiment of the battery module  22  incorporating seven cells  40  with the positive terminals  58  located proximate to the negative terminal assemblies  56 . In this embodiment, the cells  40  are each coupled to a single plate  170 . However, the cells  40  may be coupled in a variety of ways, such as, shrink wrap, adhesive, bolts, etc. Having the positive terminals  58  near the negative terminal assemblies  56  may enable the cells  40  within the battery module  22  to be arranged in the same orientation, as opposed to the alternating orientation used in typical battery modules. 
         [0058]    As shown in  FIG. 13 , the cells  40 , having the terminals  56  and  58  close to one another and arranged in the same orientation, may enable the use of shorter inter-cellular connectors  172 . For example, when the terminals  56  and  58  are arranged on the same side of the bisecting line  160 , the connectors  172  may be approximately half the length of connectors  172  used when the terminals  56  and  58  are on opposite ends of the cell  40 . 
         [0059]    Further, when the terminals  56  and  58  have the small separation distance  164  (e.g., between 5 and 40% of the length  162 ), the connectors  172  may be less than half the length of connectors  172  used when the terminals  56  and  58  are on opposite ends of the cell  40 . The connectors  172  may be bus bars, wires, cables, or any suitable conducting material. Shortened connectors  172  may result in reduced cost of construction and operation of the battery module  22 . For example, shorter connectors  172  may require less overall material for construction and less wasted material from manufacturing the connectors  172 , particularly when formed by stamping. Further, shortened intercellular connectors  172  may reduce the voltage drop induced by the intercellular connectors  172 . Reducing the voltage drop may reduce power losses within the cell  40 , thereby reducing the cost of voltage sense. In the depicted embodiment, seven cells  40  are shown connected in series in the battery module  22 , but any desired number of cells  40  and arrangement may be used. 
         [0060]    Battery modules  22  composed of multiple prismatic cells  40  with rigid positive polarity containers  42  may be aptly suited for use in xEVs. Some particular advantages for xEV applications include improved energy density, increased rigidity and durability, improved module configuration, and decreased cost of production. However, these properties of the battery modules  22 , composed of multiple prismatic cells  40 , may also be useful beyond the application of xEVs. For example, the battery module  22  described with respect to  FIG. 13  may be suitable for energy storage applications. As depicted in  FIGS. 14 and 15 , the battery module  22  may act as energy storage for an alternative energy source, such as, a wind turbine  180  or a solar panel  190 . 
         [0061]    Referring to  FIG. 14 , the battery module  22  may store energy generated as wind interacts with the turbine  180  blades. As the wind turbine  180  blades begin to spin due to force from the wind, a shaft within the wind turbine  180  rotates, as well. The rotating shaft may cause magnets to interact with a conductive coil (e.g., a generator) and the resulting voltage may drive electrical current. This electrical current may be used to charge the battery module  22 . Similarly, the solar panel  190  in  FIG. 15  may be used to charge the battery module  22 . The energy stored in the battery modules  22  may then be used for simple household functions, industrial applications, or other various uses. Alternatively, the stored energy may be sent to an electric grid for dispersion to other users. Further applications of the battery modules  22  having the rigid positive polarity cells  40  may include additional battery modules, stationary power devices, portable battery modules, battery modules for HVAC systems, and use as an uninterruptable power supply, among other things. 
         [0062]    References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other embodiments, and that such variations are intended to be encompassed by the present disclosure. 
         [0063]    It is important to note that the construction and arrangement of elements of the lithium-ion cell as shown in the various embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions, and arrangement of the various embodiments without departing from the scope of the present disclosure.