Abstract:
A battery system includes a plurality of electrochemical cells each having at least one terminal and a plurality of members coupled together to form a frame for securing the electrochemical cells in place. At least one of the members has openings configured to receive the terminals of the plurality of cells and also has features for spacing apart the plurality of cells to facilitate the flow of a cooling fluid between the cells. The battery system further includes a battery management system provided at a first end of the frame and a device provided at a second end of the frame for providing the cooling fluid to the cells and to the battery management system simultaneously.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of International Application PCT/US2007/000163, filed Jan. 3, 2007, which claims the benefit of and priority to U.S. Patent Application No. 60/755,957 filed Jan. 3, 2006. International Application PCT/US2007/000163 and U.S. Patent Application No. 60/755,957 are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to the field of batteries and battery systems. More specifically, the present system relates to a system for packaging, connecting and regulating a plurality of batteries (e.g., in a cell assembly or module). 
         [0003]    It is known to provide batteries for use in vehicles such as automobiles. For example, lead-acid batteries have been used in starting, lighting, and ignition applications. More recently, hybrid vehicles have been produced which utilize a battery (e.g., a nickel-metal-hydride (NiMH) battery) in combination with other systems (e.g., an internal combustion engine) to provide power for the vehicle. 
         [0004]    Lithium-ion batteries have a higher charge density than nickel metal hydride batteries (i.e., a lithium-ion battery can be smaller than an equivalent nickel metal hydride while still holding the same charge), and therefore occupy much less space while accommodating generally similar electrical loads. 
         [0005]    It is generally known that lithium batteries perform differently than nickel-metal-hydride batteries. In some applications, it may be desirable to obtain the enhanced power and/or performance of a lithium battery. For example, lithium batteries may provide greater specific power than nickel-metal-hydride batteries. However, the application of lithium battery technology may present design and engineering challenges beyond those typically presented in the application of conventional nickel-metal-hydride battery technology. 
         [0006]    The design and management of a lithium battery system that can be advantageously utilized in a hybrid vehicle may involve considerations such as electrical performance monitoring, thermal management, and containment of effluent (e.g., gases that may be vented from a battery cell). For example, thermal management is often an important consideration for vehicles utilizing lithium battery systems because high temperatures can create dangerous situations and greatly reduce usable battery life. 
         [0007]    Typical hybrid electric vehicle batteries require 50 to 150 or more buss bars connecting individual battery cells or modules. Each of these must be separately placed and fastened onto the assembly. Each buss bar must have a wire with a terminal leading to a connector for sensing the voltage step of each cell or module. This leads to a total of 250 to 750 or more parts, including buss bars, nuts, wires, and terminals. The typical relatively complicated assembly and large number of parts required may increase manufacture, retail, and maintenance costs and may deter manufacturers and consumers from making or purchasing hybrid electric vehicles. 
         [0008]    A battery management system component for a battery module is typically separate from the battery module. Such a typical system may add further complication to the assembly of battery systems and may also increase the length of the wire(s) needed to connect the battery management system to the battery. Relatively long connecting wires may lead to the introduction of performance-affecting electrical noise that may interfere with the battery management system and/or battery system operation. Typical battery management systems and battery systems may also be difficult to maintain, service, and/or replace as the battery management system is typically not integrated with the battery module. 
         [0009]    It would be desirable to provide a battery system that includes one or more lithium batteries or cells (e.g., lithium-ion batteries or cells). It would further be desirable to provide a battery system that includes a design that is configured to provide cooling for the batteries or cells included therein. It would further be desirable to provide a battery system that is relatively simple to assemble and that used a relatively small number of parts. It would further be desirable to provide a battery system that includes a battery management system or module that is provided in relatively close proximity to the battery system, minimizing the length of wires necessary to couple the battery management system to the battery system. It would further be desirable to provide a battery system that includes a battery management system that is integrated with the battery system. 
         [0010]    It would be desirable to provide a system and/or method that satisfies any one or more of these needs or provides other advantageous features as will be apparent to those reviewing the present disclosure. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs. 
       SUMMARY 
       [0011]    One exemplary embodiment of the invention relates to a battery system that includes a plurality of electrochemical cells each having at least one terminal and a plurality of members coupled together to form a frame for securing the electrochemical cells in place. At least one of the members has openings configured to receive the terminals of the plurality of cells and also has features for spacing apart the plurality of cells to facilitate the flow of a cooling fluid between the cells. The battery system further includes a battery management system provided at a first end of the frame and a device provided at a second end of the frame for providing the cooling fluid to the cells and to the battery management system simultaneously. 
         [0012]    Another exemplary embodiment of the invention relates to a battery system that includes a plurality of electrochemical cells each having at least one terminal and a plurality of members coupled together to form a frame for securing the electrochemical cells in place. At least one of the members has openings configured to receive the terminals of the plurality of cells and also has features for spacing apart the plurality of cells to facilitate the flow of a cooling gas between the cells. The battery system also includes a plurality of connectors. Each of the connectors includes a conductive element configured for coupling to terminals of adjacent electrochemical cells to facilitate electrical current flow between the terminals of the adjacent electrochemical cells. The battery system further includes an insulating body at least partially surrounding each of the conductive elements. 
         [0013]    Another exemplary embodiment of the invention relates to a battery system that includes a plurality of electrochemical cells each having at least one terminal and a frame for securing the electrochemical cells in place. The battery system also includes a plurality of connectors. Each of the connectors includes an electrically conductive element configured for coupling to terminals of adjacent electrochemical cells to facilitate electrical current flow between the terminals of the adjacent electrochemical cells. The battery system further includes an insulating body at least partially surrounding each of the conductive elements. The battery system still further includes a device coupled to the frame for providing a cooling gas to the cells. The plurality of electrochemical cells are provided in two rows with the terminals of the plurality of electrochemical cells facing outward. Each row is partially received by an outer member having terminal holes and having features for spacing apart the plurality of cells to facilitate the flow of the cooling gas between the cells. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a cell assembly or module according to an exemplary embodiment. 
           [0015]      FIG. 2  is a plan view of the cell assembly or module shown in  FIG. 1 . 
           [0016]      FIGS. 3A and 3B  are exploded perspective views of a cell assembly or module according to an exemplary embodiment. 
           [0017]      FIG. 4  is a perspective view of the support beams for use with the cell assembly shown in  FIG. 1 . 
           [0018]      FIGS. 5A and 5B  are front and rear perspective views of an outside beam for use with the cell assembly shown in  FIG. 1 . 
           [0019]      FIG. 6A  is an elevation view of two adjacent cells for use with the cell assembly shown in  FIG. 1 . 
           [0020]      FIG. 6B  is a plan view of two adjacent cells for use with the cell assembly in  FIG. 1 . 
           [0021]      FIGS. 7A and 7B  are close-up perspective views of a portion of the cell assembly shown in  FIG. 1 . 
           [0022]      FIG. 8  is a close-up perspective view of a portion of cell assembly according to another exemplary embodiment. 
           [0023]      FIG. 9  is a perspective view of a body of a battery management system according to an exemplary embodiment. 
           [0024]      FIGS. 10A-10D  are perspective views of bodies of a battery management system according to other exemplary embodiments. 
           [0025]      FIG. 11A  is a schematic diagram of the current flow in a cell assembly. 
           [0026]      FIG. 11B  is a schematic diagram of the current flow along one side of a cell assembly. 
           [0027]      FIG. 12A  is a schematic view of the airflow through a cell assembly. 
           [0028]      FIG. 12B  is a schematic view of the airflow through top air spaces of the cell assembly shown in  FIG. 12A . 
           [0029]      FIG. 12C  is a schematic view of the airflow between cells shown in  FIG. 12A . 
           [0030]      FIG. 13A  is a perspective view of integrally formed connectors and leads for a cell assembly according to an exemplary embodiment. 
           [0031]      FIG. 13B  is a partial section view of integrally formed connectors and leads shown in  FIG. 13A  taken along line  13 B- 13 B. 
           [0032]      FIG. 14A  is a perspective view of the integrally formed connectors and leads shown in  FIG. 14A  after a punching operation. 
           [0033]      FIG. 14B  is a partial section view of the integrally formed connectors and leads after a punching operation shown in  FIG. 14A  taken along line  14 B- 14 B. 
           [0034]      FIG. 15A  is a perspective view of integrally formed connectors, leads, and beam according to an exemplary embodiment after an injection molding operation. 
           [0035]      FIG. 15B  is a partial section view of integrally formed connectors, leads, and beam as shown in  FIG. 15A  taken along line  15 B- 15 B. 
           [0036]      FIG. 16A  is a perspective view of a cell assembly according to an exemplary embodiment. 
           [0037]      FIG. 16B  is a partial perspective view of a terminal hole of the cell assembly shown in  FIG. 16A . 
           [0038]      FIG. 17A  is a perspective view of a housing for a cell assembly according to an exemplary embodiment. 
           [0039]      FIG. 17B  is an exploded view of a cell assembly and other components. 
           [0040]      FIGS. 17C and 17D  are plan views of a cell assembly according to other embodiments. 
           [0041]      FIG. 18  is a perspective view of a NiMH cell assembly. 
           [0042]      FIG. 19  is a perspective view of a cell assembly similar to that shown in  FIG. 1  according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    Referring generally to  FIGS. 1-10 , a cell assembly or battery module  20  is shown. Cell assembly  20  serves to package, connect, and regulate a group of electrochemical cells and is intended to be provided in a vehicle. According to an exemplary embodiment, cell assembly is placed in a tray or housing  10 . Cell assembly  20  comprises electrochemical cells or batteries  22 , a frame  30 , spacers  60 , connectors  64 , covers  68 , a battery management system  70 , and bolts  90 . Cell assembly  20  is scaleable and can be lengthened or shortened to accommodate different vehicles by increasing the number of cells. 
         [0044]    According to an exemplary embodiment, electrochemical cells  22  are generally prismatic lithium-ion cells and are configured to store an electrical charge. According to other exemplary embodiments, cells could take other shapes or forms (e.g., oval, round, rectangular, etc.). According to still other alternative embodiments, cells could be nickel metal hydride, nickel cadmium or any other suitable electrochemical cells. 
         [0045]    While the accompanying FIGURES illustrate particular exemplary embodiments of lithium batteries and battery systems, any of a variety of lithium batteries or battery systems may be used according to various other exemplary embodiments. For example, according to various exemplary embodiments, the physical configuration of the individual cells and/or the modules may be varied according to design objectives and considerations, and the number of cells included in the system or module may differ. 
         [0046]    Various nonexclusive exemplary embodiments of lithium batteries are shown and described in U.S. patent application Ser. No. 10/976,169, filed Oct. 28, 2004, the entire disclosure of which is hereby incorporated by reference. The batteries, modules, and other features described herein may be used in conjunction with features disclosed in U.S. patent application Ser. No. 10/976,169, as will be appreciated by those of skill in the art reviewing this disclosure. Further, according to an exemplary embodiment in which a module or system including a plurality of lithium batteries is provided, the module may be included in a system that includes a plurality of lithium battery modules of any presently known configuration or any other configuration that may be developed in the future. 
         [0047]      FIG. 1  shows a perspective view of a battery system, cell assembly, or module in a tray or housing  10  according to an exemplary embodiment.  FIG. 2  shows a plan view of a battery system, cell assembly, or module in housing  10 , according to an exemplary embodiment. Housing  10  may typically be installed into a rear portion of a vehicle, perhaps residing in a trunk portion. Housing  10  may be integral with structures of the vehicle, or may be installed into the vehicle. Housing  10  may fit the contours of the vehicle and provide stability to the various components of the battery system including frame  30 . When installed into housing  10 , a surface of housing  10  may also serve as a cover or surface of frame  30  (e.g., a bottom cover, etc.). Frame  30  may provide interfaces to various components such as forced air system  31  and battery management system  70 . According to other various embodiments, battery management system  70  and/or elements of forced air system  31  may serve as end covers or partial end covers to frame  30 . 
         [0048]    As shown in  FIG. 3A , each of the cells  22  comprise a housing or casing  23  (e.g., a can), at least one negative terminal  24 , at least one positive terminal  25 , and a vent  26 . Casing  23  is a generally hollow body that serves as a container for internal components (e.g., anode, cathode, electrolyte, etc.) of cell  22  and defines the shape of cell  22 . Negative terminal  24  is a metallic member (e.g., a bar, rod, etc.) that is conductively coupled to the anode or negative electrode (not shown) of cell  22 . Positive terminal  25  is metallic member (e.g., a bar, rod, etc.) that is conductively coupled to the cathode or positive electrode (not shown) of cell  22 . Vent  26  is a component that allows a controlled release of pressure if cell  22  fails, reducing the chance of casing  23  rupturing. 
         [0049]    As shown in  FIGS. 3A and 3B , frame  30  is a structure that provides a base to which other components of cell assembly  20  are coupled or mounted. According to an exemplary embodiment, frame  30  comprises a cover  32 , an end cover  34 , outside beams  40 , and a center beam  36 . According to various exemplary embodiments, the pieces or structures of frame  30  serve to package, space, support, and connect the cells  22 . 
         [0050]    Cover  32  (plate, cap, lid, shroud, etc.) is a generally flat member that protects and substantially seals the top (e.g., top portion, top plane, etc.) of cell assembly  20  and facilitates the passage of airflow over cells  22 . According to an exemplary embodiment, top cover  32  is configured to cooperate with outside beams  40  so that top cover  32  can be bolted to outside beams  40 . Top cover  32  also includes a series of spaced apertures configured to receive bolts  90  extending from or through end cover  34 . According to other exemplary embodiments, top cover  32  may be coupled to outside beams  40  by other methods (e.g., snap fit, rivets, interference fit) or may be integrally formed with one or more other frame components. 
         [0051]    According to an alternative embodiment, cover  32  is a member that protects and substantially seals the bottom (e.g., bottom portion, bottom plane, etc.) of cell assembly  20  and facilitates the passage of airflow over cells  22 . According to other various exemplary embodiments, a top cover and a bottom cover may be provided and may both facilitate the passage of airflow over and/or around cells  22 . According to another exemplary embodiment, a surface or plane of housing  10  may serve as one or more covers (top and/or bottom) of cell assembly  20 , facilitating the passage of airflow over cells  22 . 
         [0052]    End cover  34  (e.g., plate, cap, etc.) is a generally flat member that protects one distal end of cell assembly  20 . According to an exemplary embodiment, end cover  34  is configured to cooperate with outside beams  40 , top cover  32 , and center beam  36  so that end cover  34  can be bolted to outside beams  40 , top cover  32 , and center beam  36  in a manner that defines one or more spaces  35  (shown, for example, in  FIG. 12B ) above and/or below cells  22  to facilitate airflow over and/or under cells  22 . According to other exemplary embodiments, end cover  34  may be coupled to outside beams  40 , top cover  32 , and center beam  36  by other methods (e.g., snap fit, rivets, interference fit, etc.) or may be integrally formed with one or more other frame components. End cover  34  is shown as being shorter than outside beams  40 , but end cover  34  may be longer than outside beams  40  depending on the number of cell rows and/or the number of cells in each row. According to some various exemplary embodiments, end cover  34  may provide an interface between frame  30  and forced air system  31  and may help control cooling gas flow from forced air system  31  to the various spaces and components of cell assembly  20  and frame  30 . 
         [0053]    Referring to  FIGS. 3A-5B , outside beam  40  is a generally elongated member that provides rigidity to frame  30 , locates and spaces cells  22 , restrains cells  22 , supports cells  22 , and allows access to terminals  24 ,  25 . Outside beam  40  comprises a web portion  41  with a back side  43  (e.g., inside, cell side, interior side, etc.) and a front side  42  (e.g., outside, connection side, exterior side, etc.), flanges  44 , fins  46 , guiding surfaces  48 , terminal holes  50 , terminal shrouds  52 , vent holes  54 , vent shrouds  56  and holes  58 . According to an exemplary embodiment, outside beams  40  of frame  30  may be considered side beams  40  as they may form or serve as the sides of a rectangular frame  30 . 
         [0054]    As shown in  FIGS. 4 and 5A , back side  43  of outside beam  40  is illustrated according to an exemplary embodiment. Back side  43  is generally configured to help support cells  22  and to at least assist in controllably providing a space between cells  22  such that a space between adjacent cells is provided. The space between adjacent cells is configured to allow airflow between adjacent cells for cooling purposes. Front side  42  is shown in  FIG. 5B  according to an exemplary embodiment. Front side  42  may generally be configured to provide access and/or connection to cell terminals protruding through terminal holes  50 . According to various other exemplary embodiments, the orientation and shape of back side  43  and front side  42  of beam  40 , and the components thereof, may be different from that shown in the  FIGS. 4 and 5 . 
         [0055]    Flanges  44  are provided along the top and bottom longitudinal edges of outside beam and generally add rigidity to outside beam  40  by increasing bending strength. Fins  46  are protrusions or extensions (e.g., projections, spines, protuberances, partitions, etc) spaced at regular intervals along the longitudinal axis of outside beam  40  on the back side  43  of web portion  41  and generally along the top and bottom edges. Guiding surfaces  48  are surfaces (e.g., slopes, lead-ins, ramps, etc.) spaced at regular intervals on the back side  43  of web portion  41  and generally in line with fins  46 . Fins  46  and guiding surfaces  48  serve to align and space cells  22  by guiding them to be received into the spaces between adjacent fins  46 . Once cells  22  are received by fins  46  and guiding surfaces  48 , terminal holes  50  may receive terminals  24  and  25  of cells  22 . According to various other exemplary embodiments, fins  46  and guiding surfaces  48  may be configured differently to match the specific shape and/or orientation of cells  22 . For example, to the extent surfaces of cells  22  are angled or rounded, the fins and guiding surfaces may also be shaped accordingly. 
         [0056]    Terminal holes  50  are openings (e.g., apertures, passages, etc.) spaced at regular intervals along the longitudinal axis of outside beam  40  generally in line with the spaces between fins  46  that are configured to receive terminals  24 ,  25  of cells  22  and allow terminals  24 ,  25  to extend through web portion  41  but prevent casings  23  of cells  22  from extending through web portion  41 . According to an exemplary embodiment, terminal holes  50  are generally round. According to other exemplary embodiments, terminal holes  50  could be oval, square, rectangular or any other shape suitable for receiving terminals  24 ,  25  of cells  22 . Terminal shrouds  52  are outwardly extending flanges (e.g., fins, guards, projections, etc.) on the front side  42  of web portion  41  around the circumference of terminal holes  50  and generally serve to protect terminals  24 ,  25  of cells  22  and reduce the chance of short-circuiting and accidental shock. According to an exemplary embodiment, terminal shrouds  52  extend partially around the circumference of terminal holes  50 . According to other exemplary embodiments, terminal shrouds  52  may extend fully around circumference of terminal holes  50  or more or less than in exemplary embodiments. 
         [0057]    Vent holes  54  are openings (e.g., apertures, passages, etc.) spaced at regular intervals along the longitudinal axis of outside beam  40  generally in line with the spaces between fins  46  that are configured align with vents  26  on individual cells  22 . According to an exemplary embodiment, vent holes  54  are generally round. According to other exemplary embodiments, vent holes could be oval, square, rectangular or any other shape. Vent shrouds  56  are outwardly extending flanges (e.g., fins, guards, projections, etc.) on the front side  42  of web portion  41  around the circumference of vent holes  54  and generally serve to protect vents  26 . According to an exemplary embodiment, outside beam  40  includes a plurality of additional holes  58  that may serve as openings for wire ties (e.g., fasteners, hold downs, etc.) to secure voltage sense leads. 
         [0058]    To facilitate the coupling of outside beam  40  to top cover  32 , end cover  34 , battery management system  70 , and vehicle, outside beam  40  includes a series of spaced apertures configured to receive bolts extending from or through top cover  32 , end cover  34 , battery management system  70 , and vehicle. According to other embodiments, outside beam  40  could be coupled to other components by other means (e.g., snap fit, rivets, interference fit). 
         [0059]    Center beam  36  is a generally elongated member or element that provides rigidity to frame  30  and locates and spaces cells  22 . According to an exemplary embodiment, center beam  36  comprises a web portion  37 , a flange portion  38 , and fins  39 . Web portion  37  is a generally flat body and serves as the main body of center beam  36 . Flange portion  38  includes flanges extending from either side of web portion  37  and extends around the circumference of web portion  37 . According to an exemplary embodiment, flange portion  38  includes a single continuous flange. According to other exemplary embodiments, flange portion could include multiple continuous flanges or a discontinuous flange. Fins  39  are protrusions (e.g., projections, spines, protuberances, partitions, etc) spaced at regular intervals along the longitudinal axis of outside beam on both sides of web portion  37  and generally along the top and bottom edges. Fins  39  may serve, locate, support and space cells  22 . 
         [0060]    To facilitate the coupling of center beam  36  to end cover  34  and battery management system  70 , center beam  36  includes a series of spaced apertures configured to receive bolts extending from or through end cover and battery management system. According to other exemplary embodiments, center beam may include additional apertures to facilitate coupling center beam to other components (e.g., top plate, vehicle, etc.). According to still other embodiments, center beam could be coupled to other components by other means (e.g., snap fit, rivets, interference fit). 
         [0061]    Referring to  FIGS. 6A and 6B , according to an exemplary embodiment, an elevation view and plan view of two adjacent cells for use with the battery system are respectively shown. The battery system may make use of spacers oriented between adjacent cells  22  and may assist in the controlled spacing and stability of cells  22  while facilitating airflow between the adjacent cells. Spacers  60  are members or elements that include a web portion  61  and a plurality of ribs  62  and serve to separate and allow the flow of a cooling gas such as air between adjacent cells  22 . Web portion  61  is a generally flat, thin body. Ribs  62  are bodies (e.g., fins, flanges, ridges, etc.) that extend outward from both sides of web portion  61 . Spacers  60  are oriented between adjacent cells  22  in a manner which allows airflow between adjacent cells  22  through channels between adjacent ribs  62 . According to other exemplary embodiments, ribs may vary in spacing and dimensions, varying the size and number of channels and the spacing between adjacent cells. 
         [0062]    Referring to  FIGS. 3A ,  3 B, and  7 A, connectors  64  are members or elements that generally serve to connect terminals  24 ,  25  of adjacent cells  22  and allow electrical current to flow between adjacent cells  22 . Connectors  64  have openings that serve to allow terminals  24 , of cells  22  to extend partially or completely in to connector  64  and comprise a pair of terminals  65  and an insulating body  66 . Terminals  65  receive terminals  24 ,  25  and are composed of a continuous body or otherwise coupled to allow electrical current to flow between terminals  65 . Insulating body  66  is a non-conductive material (e.g., PVC, ABS, etc.) and surrounds terminals  65 . Insulating body  66  reduces the chance of electrical shock. According to an exemplary embodiment, connectors  64  snap on to terminals  24 ,  25  of cells  22 . According to other exemplary embodiments, cells could be connected with bolt and buss bars or any other suitable electrical connection. According to yet other exemplary embodiments, cells could be connected with connectors installed or formed within outer beams. 
         [0063]    Covers  68  are generally long flat members that shield negative terminal  24 , positive terminal  25 , and any other high voltage wires and connections and generally serve to reduce the chance of electric shock. 
         [0064]    Referring to  FIGS. 1 ,  2 ,  3 ,  7 A,  7 B, and  8 , battery management system  70  is provided to control various aspects of the battery system. For example, the battery management system  70  may act to control the charge level and charge rate of individual cells  22  in the system. Battery management system  70  may include various circuitry and software that is configured to control such functions. The particular configuration of the battery management system may vary according to various exemplary embodiments, and may include any of a variety of features configured to control or monitor various aspects of the battery system. 
         [0065]    According to an exemplary embodiment, battery management system  70  comprises a body  72  (e.g., a housing, casing, container, etc.), shunt terminals  74 , shunt connectors  75 , cable connectors  83 , high voltage connections  76 , and low voltage connections  78 . Body  72  serves as an end cover for the end of cell assembly  20  opposite end cover  34  and houses all internal components of battery management system  70  (e.g., circuitry, memory, etc.). Various exemplary embodiments of battery management system bodies are shown in FIGS.  9  and  10 A- 10 D. 
         [0066]    Shunt terminal  74  provides a connection point for current shunts for cell assembly  20 . According to an exemplary embodiment, shunt terminals  74  are located on the end of body  72  in line with connectors  64 . Shunt connectors  75  couple shunt terminals  74  to terminals  24 ,  25  and serve to transfer electrical current from terminals  24 ,  25  to the shunt. According to another exemplary embodiment, shunt terminals  74  could be located on the end of body  72  opposite cell assembly  20 . Cable connectors  83 , are configured to provide terminals for output cables (e.g., ring terminals, quick connect with protective shroud, etc.). High voltage connections  76  receive high voltage sense leads, which are conductive members (e.g., lines, wires, strips, conduits, etc.) that facilitate collecting voltage measurements and other electrical measurements for individual cells. Low voltage connections  78  receive low voltage leads. 
         [0067]    Referring generally to the FIGURES, according to an exemplary embodiment, battery management system  70  is configured to cooperate with outside beams  40 , top cover  32 , and center beam  36  so that battery management system  70  can be bolted to outside beams  40 , top cover  32 , and center beam  36  and in a manner that defines one or more spaces  35  above and/or below cells  22  to facilitate airflow over cells  22 . According to other exemplary embodiments, battery management system  70  may be coupled to outside beams  40 , top cover  32 , and center beam  36  by other methods (e.g., snap fit, rivets, interference fit, etc.). According to an exemplary embodiment, battery management system  70  is a dual-level system. According to other exemplary embodiments, the battery management system could be a single level system. According to still other exemplary embodiments, battery management system could have alternate locations and orientations of high voltage connections, low voltage connections, shunt connections and cable connections. 
         [0068]    Referring to  FIG. 11A , a schematic diagram of the current flow through the battery system is shown, according to an exemplary embodiment. Current may be output to and received from the rest of the vehicle via a vehicle power system interface  111 . Current may flow through the plurality of cells packaged in the frame, and battery management system  70 . Referring to  FIG. 11B , a schematic diagram of the current flow along one side of a cell assembly is shown, according to an exemplary embodiment. If the cells are oriented such as the cells shown in  FIG. 6B , where terminals  25  and  24  are oppositely oriented in adjacent cells, the current will flow through adjacent cells, from positive terminal to negative terminal, and so on. According to various exemplary embodiments, the cell orientation and the current flow through the cells may be different than that shown in  FIGS. 11A and 11B . 
         [0069]    Referring now to  FIGS. 12A ,  12 B and  12 C, a schematic representation of the flow of a gas such as air through cell assembly  20  is shown. According to an exemplary embodiment, air is provided to cell assembly  20  by a source (shown as a fan of forced air system  31 ). According to an exemplary embodiment, air is forced into spaces  35  above cells  22  and downward between cells  22  through channels defined by ribs  62  of spacers  60 . According to other exemplary embodiments, air could be forced into spaces  35  below cells  22  and upward in-between cells  22  through channels defined by ribs  62  of spacers  60 . While forced air system  31  is shown as a forced air system having a fan, forced air system may be of any type or design of the past, present or future capable of providing cooling gas to cell assembly  20 .  FIG. 12A  illustrates forced air being provided across the two rows of cells  22  down the longitudinal axis of the frame and beams, using spaces created above or below cells  22  by the structures of the frame.  FIG. 12B  illustrates air being forced into a space created above cells  22  by the coupling of the top cover to the outside beams. Air initially flowing above cells  22  (e.g., as shown in  FIG. 12B , etc.), may further flow down between cells  22  and below cells  22  by the spaces created between and below cells  22  by the frame.  FIG. 12B  also illustrates a bottom cover  33  that may couple or attach to the outside beams similarly to the top cover  32 .  FIG. 12C  illustrates that air flowing above or below cells  22  may flow into each space created between cells  22  by the structures of the battery system (e.g., fins  39 , fins  46 , guides  48 , holes  50 , spacer  60 , etc.). 
         [0070]    Referring now to  FIGS. 13-16  and according to another exemplary embodiment, beam  80  is shown. Beam  80  is a generally elongated member that provides rigidity to frame  30  and locates and spaces cells  22 . Beam  80  also provides conductive paths with integrally formed connectors  87 . According to one exemplary embodiment, beam  80  comprises a web portion  82 , flanges  84 , fins  85 , vent holes  86 , connectors  87 , leads  88  and lead holes  89 . 
         [0071]    Beam  80  may be formed or constructed by an injection molding process. A possible mold for this process is partially shown in  FIGS. 13-15 , according to an exemplary embodiment.  FIG. 13A  shows perspective view of a possible mold for the front side of an outer beam (e.g., the side opposite the cells, etc.).  FIG. 13A  shows how conductive paths, integrally formed connectors  87 , and leads  88  may be embedded or integrally formed into a beam using an injection mold.  FIG. 13B  shows a close-up perspective view of leads  88  over a mold space that will eventually form a lead hole within beam  80 .  FIGS. 14A and 14B  show a perspective view and a close-up perspective view of leads  88  bent or installed into a mold space that will eventually form a lead hold within beam  80 . 
         [0072]      FIG. 15A  shows the rear side of molded beam  80  seated within the injection mold shown in  FIGS. 13-14 , according to an exemplary embodiment. Flanges  84  are provided along the top and bottom longitudinal edges of beam  80  and generally add rigidity to beam  80  by increasing bending strength. Fins  85  are protrusions (e.g., projections, spines, protuberances, partitions, etc.) spaced at regular intervals along the longitudinal axis of beam  80  on web portion  82  and generally along the top and bottom edges of web portion  82  and serve to align and space cells  22  by guiding them to be received into the spaces between adjacent fins  85 . Vent holes  86  are openings spaced at regular intervals along the longitudinal axis of beam  80  generally in line with the spaces between fins  85  that are configured to vent individual cells  22 . According to an exemplary embodiment, vent holes  86  are generally round. According to other exemplary embodiments, vent holes could be oval, square, rectangular, or any other shape. 
         [0073]    Connectors  87  are metal members or elements that are generally thin and flat and serve to connect terminals  24 ,  25  of adjacent cells  22  and allow electrical current to flow between adjacent cells  22 . Connectors  87  have holes that serve to allow terminals  24 ,  25  of cells  22  to pass through connector  87 .  FIG. 15B  shows a close-up perspective cutaway view of connectors  87  and fins  85 . Connectors  87  are generally disposed between adjacent parallel fins  85 . According to various other exemplary embodiments, fins  85  and connectors  87  may be oriented or spaced differently and may be of other shapes and types. 
         [0074]      FIG. 16A  shows the beam of  FIG. 15A  installed onto a plurality of cells  22  having alternating positive and negative terminals, according to an exemplary embodiment. The plurality of cells  22  are received by the rear side of the beam and are spaced and supported by the web portion and fins  85  shown in  FIG. 15A . The terminals of the cells are shown as passed through the holes of the connectors.  FIG. 16B  shows a perspective close-up view of the beam of  FIG. 15A , and particularly lead hole  89  and leads  88 , according to an exemplary embodiment. 
         [0075]    Leads  88  are conductive members or elements (e.g., lines, wires, strips, conduits, etc.) that facilitate collecting voltage measurements and other electrical measurements for individual cells  22 . According to an exemplary embodiment, connectors  87  and leads  88  are pre-stamped and placed into an injection mold (e.g, such as the mold shown in  FIGS. 13A-15B , etc.). The body (e.g., web portion, flanges, fins, etc.) of beam  80  is formed by an injection molding process and surrounds connectors  87  and leads  88 . Lead holes  89  are openings that form channels and allow multiple leads  88  to be accessed at once (e.g., with a multipin connector). To facilitate the coupling of the beam to the top cover, end cover, battery management system, and vehicle, the beam may include a series of spaced apertures configured to receive bolts extending from or through the top cover, end cover, battery management system, and vehicle. According to other embodiments, the beam could be coupled to other components by other suitable means (e.g., snap fit, rivets, interference fit). 
         [0076]    According to another exemplary embodiment, connectors  87  and leads  88  may not be pre-stamped pieces. Connectors  87  could be formed from a strip of metal that is formed (e.g., separated into multiple connectors, punched with terminal holes, etc.) in the injection mold tool. According to this embodiment, leads  88  would not be integrally formed with connectors  87 . 
         [0077]    Referring now to  FIGS. 17A and 17B , the installation of cell assembly and other components into housing  10  is shown according to an exemplary embodiment. As shown in  FIG. 17A , housing  10  may include a bottom portion  171  that may serve as a bottom cover of the battery system frame and/or may otherwise attach to the bottom of the battery system frame. Housing  10  may be generally formed to fit a portion of a vehicle into which it may be installed. Referring to  FIGS. 17B and 17C , cell assembly  20  is shown in housing  10  according to other exemplary embodiments. As shown in  FIGS. 17B-17D , according to various exemplary embodiments, more than one side of cell assembly  20  may contain battery management system components and/or forced air components. 
         [0078]    Referring to  FIGS. 18 and 19 , exemplary embodiments of an NiMH battery system and a lithium-ion battery system are shown, respectively. The greater charge density of the lithium-ion cells compared to NiMH cells allows an assembly of lithium-ion cells to occupy less space than a comparable assembly of NiMH cells. 
         [0079]    Those reviewing this disclosure will appreciate that various advantageous features may be obtained utilizing the exemplary embodiments shown and described herein. For example, because the battery management system is provided in close proximity (e.g., coupled to) the battery system or module, the battery system or module may be relatively simply and easily assembled and provided in a vehicle (the battery system may be preassembled by coupling the battery management system to the module prior to installation in a vehicle or after the module is installed within a vehicle), while using less material (e.g., the length of wires required to connect the battery management system to the battery module is less than if the battery management system were provided elsewhere in the vehicle). 
         [0080]    Additionally, because the battery management system is provided adjacent or in contact with the battery system or module, the cooling gas (e.g., air) used to cool the cells of the battery system may also be used to cool the battery management system (e.g., air passing over the cells may be incident on at least a portion of the battery management system). Further, the housing of the battery management system may provide structural rigidity for the battery system by virtue of its attachment thereto. 
         [0081]    The configuration of the battery system or module is also such that a gas such as air may pass adjacent the cells of the battery system (i.e., spacers and other structures are provided to provide spacing between adjacent cells to allow air to flow past the cells). 
         [0082]    According to any exemplary embodiment, a battery system or module includes a plurality of cells that are arranged in two rows arranged back-to-back (e.g., with terminals facing outward). The cells are coupled to a frame and the frame forms air spaces above and below each row of cells. A gap is maintained between adjacent cells with spacing elements. Air is forced through air gaps and spaces above, below, and between cells, removing excess heat. Other exemplary embodiments could include more or fewer rows of cells. 
         [0083]    According to any exemplary embodiment, the battery management system is configured in a way that allows it to be used as a cover for one end of the battery or frame, simplifying the assembly, reducing the length of the wires needed to connect the battery management system to the battery, and allowing the battery management system to receiving a portion of the cooling gas flow. 
         [0084]    While the exemplary embodiments illustrated in the figures and described above are presently preferred, it should be understood that these embodiments are offered by way of example only. Accordingly, the present invention is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. 
         [0085]    It should be noted that references to “front,” “back,” “upper,” and “lower” in this description are merely used to identify various elements as are oriented in the FIGURES, with “front” and “back” being relative the vehicle in which the battery assembly is placed. 
         [0086]    For the purpose of this disclosure, the term “coupled” means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature. 
         [0087]    It is important to note that the construction and arrangement of the battery system and/or cell assembly as shown in the various exemplary embodiments is illustrative only. For example, a single piece could replace two, more, or all of the frame components, and may further simplifying assembly by reducing both labor and parts. Although only a few embodiments of the present inventions 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 recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements (e.g., battery management system, connectors, beams, etc.), the position of elements may be reversed or otherwise varied (e.g., orientation of cells), and the nature or number of discrete elements or positions may be altered or varied (e.g., more or fewer cells could be used, depending on the needs and/or space constraints of different vehicles). Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the appended claims. 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 be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present inventions as expressed in the appended claims.