Patent Publication Number: US-2023141771-A1

Title: Battery module thermal management

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/818,480, filed Mar. 13, 2020, titled “Battery Module Thermal Management” and claims priority to U.S. Provisional Application No. 62/818,618, filed Mar. 14, 2019, titled “High Performance Energy Storage Battery Module”; U.S. Provisional Application No. 62/825,170, filed Mar. 28, 2019, titled “High Performance Smart Battery”; U.S. Provisional Application No. 62/926,124, filed Oct. 25, 2019, titled “Battery Pack Thermal Management” and U.S. Provisional Application No. 62/983,225, filed Feb. 28, 2020, titled “Battery Pack Thermal Management”, the disclosures of which are hereby incorporated by reference in their entireties. To the extent appropriate a claim of priority is made to each of the above-disclosed applications. 
    
    
     BACKGROUND 
     Cooling battery products is critical for their operation, safety and cycle life. Many solutions offer to cool the sides of the battery cells and not on the conducting ends where most of the heat is rejected. Pulling heat from the ends of the cells (lead plates) can be an effective means but is more difficult because of the exposure to cell voltage and the need to maintain gas-venting pathways. Accordingly, improvements are desired. 
     SUMMARY 
     This disclosure is directed to systems and methods to optimize cooling while providing electrical isolation and cell gas-venting channels in a battery module. In one aspect, the disclosure involves the integration of a heatsink (with or without an integrated cold plate) with a battery module in order to improve thermal performance. Thermally conductive pads create an electrically isolated interface between a plurality of series-connected battery-cell lead plates, at different potentials, and the heatsink. Optimization, by stacking thin and thick thermally conductive pads, allows for creation of gas-venting channels along the positive cell terminal locations. The heatsink, and optionally a cold plate, aids in cooling thermal material in the event of cell gas venting. 
     In one example, a battery module includes an enclosure including a first and second heat sink covers, each including features for dissipating heat and a plurality of battery cells positioned between the first and second heat sink covers, and being arranged with alternating polarity such that positive terminals of at least some of the battery cells face the first heat sink cover and such that positive terminals of at least some others of the battery cells face the second heat sink cover. The battery module can further include one or more first lead plates positioned between the first heat sink cover and the plurality of battery cells, the one or more first lead plates being electrically connected with at least some of the battery cells. The battery module can further include a first thermally conductive layer extending between and contacting the one or more first lead plates and the first heat sink cover, the first thermally conductive layer being shaped to at least partially defining a gas vent channel in fluid communication with the positive terminals of at least some of the plurality of battery cells. 
     In some examples, the first thermally conductive layer includes a first thermally conductive pad in contact with the first heat sink cover and includes a second thermally conductive pad in contact with the first thermally conductive pad and the one or more first lead plates. 
     In some examples, the first thermally conductive pad is adhered to the first heat sink cover and the second thermally conductive pad is adhered to the one or more first lead plates. 
     In some examples, the first thermally conductive pad is formed a solid layer. 
     In some examples, the second thermally conductive pad defines the gas-venting channel. 
     In some examples, the second thermally conductive pad has a thickness that is greater than a thickness of the first thermally conductive pad. 
     In some examples, the first and second heat sink covers include fins. 
     In some examples, the battery module can further include one or more second lead plates positioned between the second heat sink cover and the plurality of battery cells, the one or more second lead plates being electrically connected with at least some of the battery cells and can include a second thermally conductive layer extending between and contacting the one or more second lead plates and the second heat sink cover, the second thermally conductive layer being shaped to at least partially defining a gas vent channel in fluid communication with the positive terminals of at least some of the plurality of battery cells. 
     In some examples, the first and second thermally conductive layers each includes a first thermally conductive pad in contact with a second thermally conductive pad. 
     In some examples, the first thermally conductive pad of the first thermally conductive layer is in contact with the first heat sink cover and the first thermally conductive pad of the second thermally conductive later is in contact with the second heat sink cover. 
     In some examples, the second thermally conductive pad of the first thermally conductive layer is in contact with the one or more first lead plates and the second thermally conductive pad of the second thermally conductive later is in contact with the one or more second lead plates. 
     In some examples, the first thermally conductive pads of the first and second thermally conductive layers are respectively adhered to the first and second heat sink cover and wherein the second thermally conductive pads of the first and second thermally conductive layers are respectively adhered the one or more first and second lead plates. 
     In some examples, the first thermally conductive pads are formed a solid layer. 
     In some examples, the second thermally conductive pads define the gas-venting channel. 
     In some examples, the second thermally conductive pads have a thickness that is greater than a thickness of the first thermally conductive pads. 
     A battery module with simple construction and superior thermal performance comprises an array of individual battery cells with a network of parallel and series electrical connections, and one or more structural interfaces that mechanically support and protect the cells while efficiently transferring heat to the surface of the module. 
     An energy storage module can include a shell having inner faces and outer faces, the inner faces including ribs to support battery cells in retentive thermal contact, and outer faces having cooling structures for transferring heat to surrounding fluid. 
     In some examples, the shell is formed in a clam shell shape. 
     In some examples, the cooling structures comprise fins. 
     In some examples, the fins comprise at least one of interrupted fins, linear fins, and textured fins. 
     In some examples, the shell comprises a pair of interface plates coupled by a hinge. 
     In some examples, the ribs comprise sockets having sides to thermally couple to batteries. 
     In some examples, the module further includes thermally conductive metallic pins thermally coupled to and extending outward from the shells. 
     In some examples, the metallic pins are thermally isolated from supported batteries by the shell. 
     In some examples, the metallic pins are overmolded directly into the shell. 
     In some examples, the module further includes multiple battery cells thermally coupled to the ribs. 
     In some examples, the module further includes a network of parallel and series coupled electrical connections positioned to couple to the battery cells. 
     A battery device includes an enclosure having an inlet and an outlet. A plurality of battery modules are supported by the enclosure between the inlet and the outlet. A plurality of fluid paths are disposed between the inlet and the outlet positioned to provide heat convective airflow across the battery modules. A fan may be supported by the enclosure to cause the heat convective airflow. A battery module may include fins to conduct heat away from the batteries in the module. The battery terminals may be potted with a thermally conductive potting material. 
     A battery device can include an enclosure having an inlet and an outlet, a plurality of battery modules supported by the enclosure between the inlet and the outlet, a plurality of fluid paths disposed between the inlet and the outlet positioned to provide heat convective airflow across the battery modules, and a fan supported by the enclosure to cause the heat convective airflow. 
     In some examples, the fan is supported proximate the outlet to cause the fluid to flow into the inlet from ambient and out of the outlet to ambient. 
     In some examples, the inlet comprises at least one of a screen, baffles, and louvers to prevent ingress of water. 
     In some examples, the battery modules comprise fins applied to external faces of the batter modules to facilitate convective cooling by the fluid flow. 
     In some examples, the fluid comprises air. 
     In some examples, at least one of the plurality of battery modules include a case, multiple spaced apart batteries supported within the case, interconnects electrically coupling anodes and cathodes of the batteries, and a potting material encapsulating the interconnects, anodes, and cathodes. 
     In some examples, the case comprises two ends, each end including a vent to allow airflow between the spaced apart batteries. 
     In some examples, the vents are protected by one or more of screens, baffles, and filters. 
     In some examples, the potting material is supported by the case and comprises a flowable thermal adhesive. 
     In some examples, the potting material comprises an electrically protective resin that is formed by spraying or dipping. 
     In some examples, at least one of the plurality of battery modules includes a case, multiple spaced apart batteries supported within the case, interconnects electrically coupling anodes and cathodes of the batteries, and a thermal layer in close thermal communication with the batteries and the case. 
     In some examples, the case comprises a plurality of heat conductive fins thermally fixed to an outside portion of the case. 
     In some examples, the fins are rounded at an end opposite the case. 
     In some examples, the fins are compliant metallic fins. 
     A battery module can include a case, multiple spaced apart batteries supported within the case, interconnects electrically coupling anodes and cathodes of the batteries; and a thermal layer in close thermal communication with the batteries and the case. 
     In some examples, the case further includes a plurality of heat conductive fins thermally fixed to an outside portion of the case. 
     In some examples, the fins are rounded at an end opposite the case. 
     In some examples, the fins are compliant metallic fins. 
     A battery module can include a case, multiple spaced apart batteries supported within the case, interconnects electrically coupling anodes and cathodes of the batteries; and a potting material encapsulating the interconnects, anodes, and cathodes. 
     In some examples, the case includes two ends, each end including a vent to allow airflow between the spaced apart batteries. 
     In some examples, the vents are protected by one or more of screens, baffles, and filters. 
     In some examples, the potting material is supported by the case and comprises a flowable thermal adhesive. 
     In some examples, the potting material comprises an electrically protective resin that is formed by spraying or dipping. 
     In some examples, the cells are assembled in a dense array with parallel axes and coincident faces, such that as a whole they form a planar slab. 
     In some examples, the design enables a simple module with high thermal performance that is entirely sealed to prevent ingress of water, dust, humidity, or other harmful materials. 
     A smart battery device has a simple construction and superior thermal performance. The smart battery device includes an enclosure containing a plurality of removable battery modules. The modules contain and protect a plurality of battery cells connected by electrically conductive interconnects, such as metallic interconnects. The modules may be designed with features that enhance the transmission of heat that is generated in the cells and interconnects to one or more module surfaces. The enclosure includes an arrangement of channels and interface surfaces designed to efficiently and evenly convey heat from the modules to a passing flow of air, which is used to reject the heat from the battery product. 
     In one embodiment, the enclosure features inlet and outlet plenums which divide and apportion the air substantially evenly among the battery modules by management of the fluidic resistance throughout the fluidic circuit. A fan draws air through the assembly of modules, and exhausts it out of the smart battery enclosure. 
     In some embodiments, the battery modules feature openings on one or more faces, permitting the flow of air to pass through and among the battery cells themselves, stripping generated heat from the cells by forced convection. The ends of the cells and associated metallic interconnects may be protected from the passing flow of air by pottant or resin applied to either end of the cells. 
     In other embodiments, the battery modules are substantially sealed to protect the cells, and heat generated in each cell is conducted axially outward along the length of the cell, further conducted through a thermally conductive, electrically insulating adhesive into side plates, and further convected to a passing flow of air with the help of fins or similar thermally conductive features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an example battery module having features in accordance with the present disclosure. 
         FIG.  2    is an exploded perspective view of the battery module of  FIG.  1   . 
         FIG.  3    is an exploded side view of the battery module of  FIG.  1   . 
         FIG.  4    is a schematic cross-sectional side view of the battery module of  FIG.  1   . 
         FIG.  5    is a perspective view of a battery module cover of the battery module of  FIG.  1   . 
         FIG.  6    is a top view of the battery module cover of  FIG.  6   . 
         FIG.  6 A  is a top view of the battery module cover of  FIG.  6   , with an alternative fin design. 
         FIG.  6 B  is a top view of the battery module cover of  FIG.  6   , with an alternative fin design. 
         FIG.  7    is a side view of the battery module cover of  FIG.  6   . 
         FIG.  8    is a perspective view of a first thermally conductive pad of the battery module of  FIG.  1   . 
         FIG.  9    is a top view of the first thermally conductive pad of  FIG.  8   . 
         FIG.  10    is a side view of the first thermally conductive pad of  FIG.  8   . 
         FIG.  11    is a top view of second thermally conductive pads associated with a first side of the battery module of  FIG.  1   . 
         FIG.  12    is a top view of second thermally conductive pads associated with a second side of the battery module of  FIG.  1   . 
         FIG.  13    is a perspective view of a first configuration of a second thermally conductive pad of the battery module of  FIG.  1   . 
         FIG.  14    is a side view of the second thermally conductive pad of  FIG.  13   . 
         FIG.  15    is a top view of the second thermally conductive pad of  FIG.  13   . 
         FIG.  16    is a perspective view of a second configuration of a second thermally conductive pad of the battery module of  FIG.  1   . 
         FIG.  17    is a side view of the second thermally conductive pad of  FIG.  16   . 
         FIG.  18    is a top view of the second thermally conductive pad of  FIG.  16   . 
         FIG.  19    is a perspective view of a third configuration of a second thermally conductive pad of the battery module of  FIG.  1   . 
         FIG.  20    is a side view of the second thermally conductive pad of  FIG.  19   . 
         FIG.  21    is a top view of the second thermally conductive pad of  FIG.  19   . 
         FIG.  22    is a top view of the battery module of  FIG.  1   , with the top cover and first thermally conductive pad removed such that the second thermally conductive pads shown in  FIG.  11    can be viewed in an installed condition. 
         FIG.  23    is a bottom view of the battery module of  FIG.  1   , with the bottom cover and a first thermally conductive pad removed such that the second thermally conductive pads shown in  FIG.  12    can be viewed in an installed condition. 
         FIG.  24    is a partial cross-sectional view of an alternative configuration for the battery module shown at  FIG.  1   . 
         FIG.  25    is a partial cross-sectional view of an alternative configuration for the battery module shown at  FIG.  1   . 
         FIG.  26    is a cross-sectional view of a system including an enclosure for holding a plurality of battery modules. 
         FIG.  27    is a partial cross-sectional view of an alternative configuration for the battery module shown at  FIG.  1   , usable within the enclosure of  FIG.  26   . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
     The importance of distributed energy storage is increasing rapidly, due to the growth of solar and other distributed energy technologies, which have become a significant source of energy on electric grids worldwide. As energy storage becomes a key part of grid technology, cost-effective battery storage that is capable of performing multiple charge/discharge cycles per day is becoming increasingly important. Further, as millions of storage units are deployed, it will be valuable to reduce the cost and complexity of these systems, particularly relating to cooling systems and moving parts. 
     Electric grids and the use of distributed energy storage devices would benefit from a simple, cost-effective modular energy storage battery product that is fast and simple to install, physically compact, and capable of delivering multiple charge/discharge cycles per day, without the complexity of liquid cooling or other special techniques. 
     In one aspect, the disclosure includes systems and methods providing a way to maintain operational-range cell temperatures in a battery module  100  while maintaining the safety features of the battery module  100 . For example, and as explained in further detail below, the battery module  100  includes a plurality of cells  102 , such as cylindrical 18650 or 21700-type lithium cells, provides a cooling pathway from cells  102  within the battery module  100  while simultaneously defining gas venting pathways of the cells  102 . 
     To cool a battery module  100  having cylindrical cells  102 , heat must be removed from the outer surfaces of the cells  102 , for example the circumferential outer surface  102   a  and/or the end surfaces  102   b  of the cells  102 . In some configurations and applications, heat conducts more readily from the end surfaces  102   b , which includes the positive and negative terminals of the cells  102 , in comparison to the circumferential outer surface  102   a  of a cell. As the ends  102   b  of the cells  102  are electrically active, a thermally conductive and electrically isolated interface material can be utilized such that contact to a grounded heatsink, for example the battery module cover  108 , can be established. 
     In the present disclosure, and as can be seen at  FIGS.  4 ,  22 , and  23   , lead plates  110 ,  111  are used to electrically connect groups of cells  102  at each of the respective ends  102   b  of the cells  102 . The lead plates  110 ,  111  can act as a thermal connection point to the cover  108  acting as a heat sink. However, the lead plate  110 ,  111  is electrically active so it must also be electrically isolated from the cover  108 . To provide an electrically isolated, thermally conductive connection between the between the lead plates  110  and the cover  108  of the battery module  100 , the present disclosure utilizes multiple layers  104 ,  105 ,  106 ,  107  of thermal conductive, electrically isolating material that create channels  112 ,  113  for safely venting cell gases to the outside of the module  100  while pulling heat from the lead plates  110 , as is discussed in more detail below. 
     Referring to  FIGS.  1  to  4   , an example battery module  100  is presented. The battery module  100  may also be referred to as a smart battery or a battery pack. As shown, the battery module  100  includes a plurality of battery cells  102  secured within a housing  103 , which can include, for example, upper and lower battery holder frames  103   a ,  103   b  and a chassis  103   c . The aforementioned lead plates  110 ,  111  are also secured to the housing  103 , for example secured to the first and second battery holder frames  103   a ,  103   b . A control module  114  is also secured to the chassis  103   c  and is shown as partially forming a face of the battery module  100 . The control module  114  can include electronics for controlling charging and discharging of the battery cells  102  and interfacing with external equipment, such as solar panels. The control module  114  is also shown as including a plurality of ports and jacks  114   a  for accomplishing such purposes. 
     A first cover  108  and a second cover  109  are also provided and are respectively positioned over the holder frames  103   a ,  103   b  to enclose the battery module  100  in cooperation with the holder frames  103   a ,  103   b  and the chassis  103   c . Fasteners  101 , such as screws or bolts, extend between the covers  108 ,  109  to secure the assembly together. In the example shown, the first and second covers  108 ,  109  are configured to act as heat sinks for the battery module  100  such that heat can be dissipated away from the battery cells  102 . To that end, the first and second covers  108 ,  109  can be provided with a plurality of fins  108   a ,  109   a  to aid in heat dissipation. In some examples, the covers  108 ,  109  can be integrated with cold plates, for example liquid cooled cold plates. Other devices, such as heat pipes could be integrated as well. In addition to cooling the battery module  100 , cold plate designs could be used to heat the battery module  100  with warmed coolant in colder climates or conditions. 
     With reference to  FIGS.  2  to  4   , and as mentioned previously, the battery module  100  can be further provided with electrically isolating, thermally conductive layers  104 ,  105 ,  106 ,  107  that allow for heat to be transferred from the battery cells  102  to the covers  108 ,  109 . Immediately adjacent to the covers  108 ,  109  are thin thermally conductive layers or first thermally conductive pads  104 ,  105 . In one example, the first thermally conductive pads  104 ,  105  are respectively adhered to the covers  108 ,  109  by an adhesive. In one example, the first thermally conductive pads  104 ,  105  are solid sheets. The first thermally conductive pads  104 ,  105  satisfy the voltage requirement for separating the lead plates  110 ,  111  from the grounded covers  108 ,  109 . 
     The second thermally conductive pads  106 ,  107  are provided as a plurality of separate pads adhered to the lead plates  110 ,  111 , for example by an adhesive. In contrast to the first thermally conductive pads  104 ,  104 , the second thermally conductive pads  106 ,  107  are provided with cutouts which allow for optimized contact with the lead plates  110 ,  111  while ensuring that the gas vents at the positive end of the battery cells  102  remain free and unblocked. Accordingly, the shaping of the second thermally conductive pads  106 ,  107  creates gas-venting channels  112 ,  113  that extend along the length of the lead plate  110 . Accordingly, any gas venting from a positive terminal of a battery cell  102  can travel along the length of the gas-venting channel  112 ,  113 , partially defined by the thermally conductive pads  104 ,  106 , to the end of the plate  110 . 
     With reference to  FIGS.  5  to  7   , an example heat sink cover  108 ,  109  is shown in isolation. In the example shown, the covers  108 ,  109  are cast aluminum and are provided with fins  108   a ,  109   a  for improving heat dissipating performance. In one aspect, the thickness of the heatsink covers  108 ,  109  add rigidity and structural safety to the battery module  100 . The heatsink covers  108 ,  109  are also shown featuring a plurality of holes  108   b ,  109   b  for receiving fasteners  101  for bolting the battery module  100  together. 
       FIGS.  6 A and  6 B  show alternative fin arrangements in which the fins  108   a ,  109   a  can be provided in a different pattern and/or configuration. In  FIG.  6 A , the fins  108   a ,  109   a  are provided as a plurality of independent projections extending from the covers  108 ,  109 . In  FIG.  6 B , the fins  108   a ,  109   a  are shown as, moving from left to right on the page, interrupted fins, linear fins, and/or textured fins. Combinations of different fin types can be used on the same cover  108 ,  109 . In some examples, forced ventilation across the fins (e.g. See  FIG.  26   ) and mist cooling or other methods may be used to increase heat transfer from the fins  108   a ,  109   a . In some embodiments, the covers  108 ,  109  and fins may wrap around the cell array to form the entire enclosure in a clamshell form as illustrated. In some embodiments, the fin array may be replaced by a metallic folded fin array, metallic fins pressed, fused, bonded, or welded to the surfaces of the case, or pressed between adjacent battery modules  100 . The use of compliant metallic fins may allow a reduction in spacing between modules, allowing for an increase in energy density of the product or device while still maintaining sufficient cooling. In some embodiments, the tips of fins  302  may be rounded or otherwise shaped so the assembly is comfortable to hold and affords a secure grip. 
     In some embodiments the covers  108 ,  109  may be fabricated from materials other than a metal material. For example, the covers  108 ,  109  a polymer and formed by a low-cost method, such as injection molding or compression molding. They may be made of an engineering resin such as ABS, polycarbonate, or nylon, or more exotic resins such as polyetherimide in special cases. Heat transfer may be increased by filling the polymer with fiber or filler with a bulk thermal conductivity higher than that of the base resin. 
       FIGS.  8  to  10    show the first thermally conductive pads  104 ,  105  in isolation. As mentioned previously, the first thermally conductive pads  104 ,  105  can be formed as solid sheets and respectively adhered to the covers  108 ,  109  by an adhesive. Although a solid sheet is shown for the pads  104 ,  105 , other configurations are possible. For example, a pad with cutout portions or apertures  110   b ,  111   b  may be provided. Also, multiple smaller pads, for example, strips of thermal padding, may be used. Where multiple portions are used, the portions may be immediately adjacent to each other such that a complete covering of the cover surface is achieved, or the portions may be spaced apart from each other such that one or more gaps result. The first thermally conductive pads  104 ,  105  may also be attached to the covers  108 ,  109  via other means besides an adhesive. Alternatively, the first thermally conductive pads  104 ,  105  can be attached to the second thermally conductive pads  106 ,  107 , for example by an adhesive. The first thermally conductive pads  104 ,  105  can also be simply compressed between the covers  108 ,  109  and the second thermally conductive pads  106 ,  107  without being physically attached to either. In the example shown, the thermally conductive pads  104 ,  105  have a thickness of about 0.2 to 0.5 mm. In the example shown, the pads  104 ,  105  are formed from “Thermally Conductive Silicone Interface Pads” provided by 3M of St. Paul, Minn., or a similar silicone-based elastomer product having high thermal conductivity and electrically insulating properties, which can be referred to as a “sil pad.” In one example, one or both of the pads  104 ,  105  is a 3M “Thermally Conductive Silicone Interface Pad  5519 ” having a thermal conductivity of about 4.9 W/m-K, a volume resistivity of about 1.7×10 14  Ohms, and a Shore 00 hardness of 70. 
       FIGS.  11  to  21    show the second thermally conductive pads  106 ,  107  in isolation. As mentioned previously, the second thermally conductive pads  105 ,  107  can be adhered to the lead plates  110 ,  111  by an adhesive. The second thermally conductive pads  105 ,  107  may also be attached to the lead plates  110 ,  111  via other means besides an adhesive. Although multiple separate pad portions are shown, a continuous sheet with cutout portions can also be used to form each of the second thermally conductive pads  105 ,  107 . Alternatively, the second thermally conductive pads  105 ,  107  can be attached to the first thermally conductive pads  104 ,  105 , for example by an adhesive. The second thermally conductive pads  105 ,  107  can also be simply compressed between the lead plates  110 ,  111  and the first thermally conductive pads  104 ,  105  without being physically attached to either. In the example shown, the thermally conductive pads  104 ,  105  have a thickness of about 3 mm. In the example shown, the pads  106 ,  107  are formed from “Thermally Conductive Silicone Interface Pads” provided by 3M of St. Paul, Minn., or a similar silicone-based elastomer product having high thermal conductivity and electrically insulating properties, which can be referred to as a “sil pad.” In one example, one or both of the pads  106 ,  107  is a 3M “Thermally Conductive Silicone Interface Pad  5519 ” having a thermal conductivity of about 4.9 W/m-K, a volume resistivity of about 1.7×10 14  Ohms, and a Shore 00 hardness of 70. 
     In some examples, the first and second thermally conductive pads  104 ,  105 ,  106 ,  107  are formed from the same material. In other examples, the first and second pads  104 ,  106  can be formed from different materials. In some examples, the features of the first and second pads  104 ,  106  and  105 ,  107  are integrated into a single pad. In some examples, the pads  104 ,  105 ,  106 ,  107  are provided with an adhesive backing. In some examples, a sprayed or otherwise applied coating can be provided instead of the pads  104 ,  105 . 
     Referring to  FIG.  11    specifically, it can be seen that the second thermally conductive pads  105  can include multiple, spaced apart individual pads  105 ,  107  that have different shapes. For example, the thermally conductive pads  105  include a first pad configuration  105   a , a second pad configuration  105   b , and a third pad configuration  105   c . The pad configurations  105   a ,  105   b ,  105   c  are provided in their respective shapes in order to cover as much of the surface area of the lead plates  110  as possible within the physical constraints defined by the battery module  100  and the frame  103   a  in particular. Referring to  FIG.  12   , the thermally conductive pads  107  are shown as including only a first configuration  107   a  that is generally the same as the pad configuration  105   b . Although seven individual pad portions for pads  105  and six individual pad portions for pads  107  are shown, more or fewer pad individual portions can be provided. As shown, the pad configuration  105   a  allows for the venting of an array with two columns or rows of battery cells  102  while the pad configurations  105   b ,  105   c ,  107   a  allow for the venting of an array with four columns or rows of battery cells  102 . Other configurations are possible. 
     In one aspect, the pads  105 ,  107  are respectively provided with cutout portions  105   c ,  105   d ,  105   e  and cutout portions  107   d ,  107   e . These cutout portions  107   d ,  107   e  provide an opening space above the ends  102   b  of the battery cells  102  such that any gasses vented from the battery cells  102  can enter into the cutout portions  107   d ,  107   e  and escape through the resulting venting passageways or channels  112 ,  113  defined between the individual pads  105 ,  107 . The venting passageways or channels  112 ,  113  are shown schematically at  FIG.  4    and also at  FIGS.  22  and  23   , where it can be seen that the passageway or channel  112 ,  113  is defined by the pads  104 ,  105  on one side and between the pads  105 ,  107 . In one aspect, the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e  have a general arc shape and form a portion of a circle with an open side facing into the venting passageway or channel  112 ,  113 . As shown, the cutout portion  105   c  have an arc length that is slightly greater than the circumference of a circle, the cutout portions  105   d ,  107   d  have an arc length significantly greater than half the circumference of a circle, and the cutout portions  105   e ,  107   e  have an arc significantly length less than half the circumference of a circle. The arc lengths are typically between 107 degrees and 306 degrees. Regardless of the particular arc length associated with the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e , each portion has an open side facing, and partially defining, the venting passageway or channel  112 ,  113  such that any gas vented from a battery cell  102  can enter into the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e  and then be guided into the venting passageway or channel  112 ,  113 . In the example shown, the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e  each correspond to a single battery cell  102 . However, the pads  105 ,  107  could be configured such that the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e  receive vented gases from more than one battery cell  102 . 
     Referring to  FIGS.  22  and  23   , the second thermally conductive pads  105 ,  107  are shown in an installed condition, where the gas venting passageways  112 ,  113  can be more easily viewed. As shown, it can be seen that the frames  103   a ,  103   b  define sidewalls  103   ad ,  103   bd , each of which defines one side of a gas venting passageway  112 ,  113  while one of the second thermally conductive pads  105 ,  107  defines the opposite side of the gas venting passageways  112 ,  113 , wherein each of the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e  have an open side facing or in fluid communication with the gas venting passageways  112 ,  113 . On the outermost sides of the battery module  100 , side edges or walls  119  can form one side of the gas venting passageway  112 ,  113 , with the thermally conductive pads  105 ,  107  forming the other side. In an alternative arrangement without sidewalls  103   ad ,  103   bd , the gas venting passageways  112 ,  113  can be defined as the space between the adjacent individual pads  105 ,  107 , as is schematically shown at  FIG.  4   . When a battery cell  102  vents gas, the gas flows through the openings  110   b ,  111   b  in the lead plates  110 ,  111 , into one of the cutout portions  105   c ,  105   d ,  105   e ,  107   d ,  107   e , and into the gas venting passageway  112 ,  113 , thereby allowing for the successful venting of gas from a battery cell  102 . Once in the gas venting passageways  112 ,  113 , the gas can then be exhausted through vents  130  in the battery module housing  103 . In one example, the gas can flow along the venting passageways  112 ,  113 , then beneath the lead plates  110 ,  111  via openings  132  in the lead plates  110 , and then through the vents  132 . The openings  132  can be fully encircled or defined openings in the lead plates  110 ,  111  or can be gaps  132  between the battery module housing  103  and lead plates  110 ,  111 . With continued reference to  FIGS.  22  and  23   , it can be seen that the second thermally conductive pads  105 ,  107  respectively cover a majority of the surface area of the lead plates  110 ,  111 , and collectively cover a majority of the surface area of the major sides of the frames  103   a ,  103   b  and the major sides of the battery module  100 . With the disclosed configuration, thermal conductivity performance is maximized while still fully maintaining the ability of the battery module  100  to vent battery cells  102  safely. 
     Referring to  FIGS.  24  and  25   , alternate configurations for a battery module  200  is presented. It is noted that the differing features of the battery module  200  may be incorporated into the battery module  100 , and vice versa.  FIG.  24    illustrates a cross section view through an example module as outlined in  FIG.  1   . In one aspect, clamshell-type interface plates  201 , 202  are provided with pin fins  210 , or any of the other types of fins described for fins  108   a ,  109   a , on their external faces as described above, and enclose an array of battery cells, for example cylindrical 18650 or 21700-type lithium cells  102 . The plates may be coupled via a hinge  225 . The interface plates are provided with ribs or sockets  230  on their internal faces which securely locate and support the cells, and these features are designed with a suitable level of mechanical interference to provide reliable thermal contact with the large cylindrical faces of the cells, without distorting or crushing the cells  102 . Gaps  240  between the sockets may be advantageous to limit thermal communication between the cells, for example to prevent thermal runaway. Additionally, axial gaps  241  at the face of each cell  102  admit the metallic cell interconnects  242 , which take the form of an interrupted plane shown in cross-section. The interconnects conduct electrical current among the cells  102  in the desired series/parallel configuration. The structure of the array of sockets  230  is interrupted to admit the metallic interconnects  242 . 
     In operation, heat that is generated in the cell and interconnects is transferred through the body of the cell by conduction, further transferred radially outward by conduction to the sockets  230 , further transferred axially outward to the planar body of the interface plates by conduction, further transferred into the array of pin fins  210  by conduction, and finally transferred into the surrounding fluid by natural or forced convection. Despite the polymer construction of the interface plates, with appropriate material selection heat transfer may be significantly enhanced relative to the performance of a less concise heat transfer path. 
     In some embodiments, thermal performance may be further enhanced by various means, for example by incorporating thermally conductive metallic pins  250  that interpenetrate the interface plates  201 ,  202 , extending from the interior of the module in the spaces between the cells  102 , and projecting axially outward into the surrounding fluid. Such an arrangement is shown at  FIG.  25   . Given the surface area and close proximity to the cell surfaces, the pins may significantly increase heat transfer, while still maintaining high-voltage isolation of the module via the interface plates  201 ,  202 . Pins  250  may be overmolded directly into the interface plates  201 ,  202  as they are formed, or machine inserted in a subsequent step. 
     Referring to  FIGS.  26  and  27   , an alternate configuration for the battery module  300  and a cabinet  390  for storing multiples of a battery module  300  are presented.  FIG.  26    illustrates a front view of an energy storage battery device or product  300  with enhanced thermal performance, comprising enclosure  390 , which houses three battery modules  300  ( 300   a ,  300   b ,  300   c ). In one embodiment, the battery module  300  is cooled by a flow of air illustrated by arrows  391 . The air enters via inlet  392  which communicates with inlet plenum  393 , which distributes the flow among battery modules  300 , etc. The air flows are indicated by arrows  391  throughout the enclosure  390 . The arrows  391  indicate that air flows across the modules  300  and enters outlet plenum  394 , where air is collected and urged out of the enclosure by fan  395  via outlet  396 . Fan  395  basically creates a pressure differential between the inlet  392  and outlet  396 , causing the air to flow through the enclosure  390 . In many cases the inlet  392  and outlet  396  may be so oriented or protected via baffles, louvers, screens etc. as to prevent ingress of water, particles, insects, etc. In further embodiments, the fan  395  may operate to draw air into the enclosure  390 , creating an airflow opposite to that shown. It is noted that the enclosure  390  could include multiple inlets  392  and can be configured to hold more or fewer battery modules  300 . The enclosure can also house multiples of the battery modules  100 ,  200  shown in  FIGS.  1 - 25    to provide for forced-air cooling across the fins to increase cooling capacity. 
     In some embodiments the air may flow across one or more surfaces of the modules to cool them by convection, aided in some cases by surface modifications such as fins applied to or between the faces of the modules as described below. In other embodiments the air may flow through the module itself, flowing across and among the cells and cooling them directly by convection. 
     The size, position, and shape of the plenums may be chosen so as to limit the fluidic pressure drop along the plenum length, and to concentrate the pressure drop across the modules, such that the flowrate and cooling effect of the flow is equalized among the modules. In one example, where the plenums are on a same end, the gaps between the case and modules may be larger the further the modules are from the inlet  392  and outlet  396  to accomplish such fluidic pressure drop. In some embodiments the modules may be arranged in multiple layers or ranks in the direction normal to the page of  FIG.  26    (e.g. 2 or 3 ranks for a total of 6 or 9 modules), with the flow further distributed among the ranks. 
       FIG.  27    illustrates a cross section view through an example smart battery module  300  utilized in the smart battery product of  FIG.  26   . The module  300  is enclosed by a protective case  390 , which may consist of clamshell-type plates formed from metal or molded from resin. The module  300  is fitted with vents  302  on both ends (one end shown), and the vents may be protected by screens  303 , baffles, filters or other protective means. 
     The module encloses a multiplicity of battery cells  102 , for example cylindrical 18650 or 21700-type lithium cells, with the cells electrically interconnected by interconnects  320  on either end. The electrically active ends of the cells and the metallic interconnects are protected by resin or pottant  330 —for instance a flowable thermal adhesive with epoxy, polyurethane, or silicone base chemistry—but the central portion of each cell is exposed to airflow  340  via openings  345 . In the case of a metallic case, dielectric sheets  331  on either side may be employed to provide voltage isolation between the cell array and the case. 
     In operation, heat that is generated in the cells  102  and interconnects  320  is transferred through the body of the cell by conduction, and further transferred by convection into the airflow  340  passing through the module  300  and through openings  345 . Even if condensation forms on the cells or if dust is deposited, it cannot corrode or short the contacts, including anodes and cathodes of the cells  102  and corresponding interconnects  320  which are protected by the resin. The contacts are basically electrically-active surfaces that are encapsulated in the resin or other suitable pottant. 
     While  FIG.  27    and the corresponding description illustrate and describe the use of a flowable pottant to protect and isolate the electrically-active surfaces, in other embodiments the assembled module may be dipped or sprayed with an electrically protective resin, for instance of the type commonly used in the manufacture of motor and generator windings, in each case effecting the electrical and environmental protection of the exposed surfaces with respect to the flow of cooling air through the module. In some embodiments, the flowable pottant approach of  FIG.  27    may be combined with the finned covers  108 ,  109  of the type shown at  FIG.  1    to form an efficient thermal path. 
     The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the full scope of the following claims.