Abstract:
Provided are cooling subsystems for energy-storage systems comprising: a coolant section having a coolant circulated therein; a plurality of battery cells having a coated portion, the coated portion being disposed in the coolant section, the coolant section configured so that the plurality of battery cells are substantially fully covered by the coolant; and a retainer disposed in the coolant section, the retainer holding the plurality of battery cells, the retainer having a plurality of flow channels, the coolant flowing through the flow channels.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 14/866,907 filed Sep. 26, 2015, which claims the benefit of U.S. Provisional Application No. 62/186,977 filed Jun. 30, 2015. This application is related to U.S. patent application Ser. No. 14/841,617 filed Aug. 31, 2015. The subject matter of the aforementioned applications is incorporated herein by reference for all purposes. 
     
    
     FIELD 
       [0002]    The present application relates generally to energy-storage systems, and more specifically to energy storage systems for vehicles. 
       BACKGROUND 
       [0003]    It should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. 
         [0004]    Electric-drive vehicles offer a solution for reducing the impact of fossil-fuel engines on the environment and transforming automotive mobility into a sustainable mode of transportation. Energy-storage systems are essential for electric-drive vehicles, such as hybrid electric vehicles, plug-in hybrid electric vehicles, and all-electric vehicles. However, present energy-storage systems have disadvantages including large size, inefficiency, and poor safety, to name a few. Similar to many sophisticated electrical systems, heat in automotive energy-storage systems should be carefully managed. Current thermal management schemes consume an inordinate amount of space. Present energy-storage systems also suffer from inefficiencies arising variously from imbalance among battery cells and resistance in various electrical connections. In addition, current energy-storage systems are not adequately protected from forces such as crash forces encountered during a collision. 
       SUMMARY 
       [0005]    This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
         [0006]    According to various embodiments, the present disclosure may be directed to cooling subsystems comprising: a coolant section having a coolant circulated therein; a plurality of battery cells having a coated portion, the coated portion being disposed in the coolant section, the coolant section configured so that the plurality of battery cells are substantially fully covered by the coolant; and a retainer disposed in the coolant section, the retainer holding the plurality of battery cells, the retainer having a plurality of flow channels, the coolant flowing through the flow channels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements. 
           [0008]      FIG. 1  illustrates an example environment in which an energy-storage system can be used. 
           [0009]      FIG. 2A  shows an orientation of battery modules in an energy-storage system, according to various embodiments of the present disclosure. 
           [0010]      FIG. 2B  depicts a bottom part of an enclosure of a partial battery pack such as shown in  FIG. 2A . 
           [0011]      FIG. 3  is a simplified diagram illustrating coolant flows, according to example embodiments. 
           [0012]      FIG. 4  is a simplified diagram of a battery module, according to various embodiments of the present disclosure. 
           [0013]      FIG. 5  illustrates a half module, in accordance with various embodiments. 
           [0014]      FIGS. 6A and 6B  show a current carrier, according to various embodiments. 
           [0015]      FIG. 7  depicts an example battery cell. 
           [0016]      FIG. 8  illustrates further embodiments of a battery half-module. 
           [0017]      FIG. 9  illustrates additional embodiments of a battery half-module. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    While this disclosure is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the disclosure and is not intended to limit the disclosure to the embodiments illustrated. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that like or analogous elements and/or components, referred to herein, may be identified throughout the drawings with like reference characters. It will be further understood that several of the figures are merely schematic representations of the present disclosure. As such, some of the components may have been distorted from their actual scale for pictorial clarity. 
         [0019]    Some embodiments of the present disclosure can be deployed in a wheeled, self-powered motor vehicle used for transportation, such as hybrid electric vehicles, plug-in hybrid electric vehicles, and all-electric vehicles. For example,  FIG. 1  illustrates electric car  100 . Electric car  100  can be an automobile propelled by one or more electric motors  110 . Electric motor  110  can be coupled to one or more wheels  120  through a drivetrain (not shown in  FIG. 1 ). Electric car  100  can include frame  130  (also known as an underbody or chassis). Frame  130  can be a supporting structure of electric car  100  to which other components can be attached/mounted, such as, for example, a battery pack  140   a.  Battery pack  140   a  can supply electricity to power one or more electric motors  110 , for example, through an inverter. The inverter can change direct current (DC) from battery pack  140   a  to alternating current (AC), as can be required for electric motors  110 , according to some embodiments. 
         [0020]    As depicted in  FIG. 1 , battery pack  140   a  may have a compact “footprint” and be at least partially enclosed by frame  130  and disposed to provide a predefined separation, for example, from structural rails  150  of an upper body that couples to frame  130 . Accordingly, at least one of rear crumple zone  160 , front crumple zone  170 , and lateral crumple zone  180  can be formed around battery pack  140   a.  Both the frame  130  and structural rails  150  may protect battery pack  140   a  from forces or impacts exerted from outside of electric car  100 , for example, in a collision. In contrast, other battery packs which extend past at least one of structural rails  150 , rear crumple zone  160 , and front crumple zone  170  remain vulnerable to damage and may even explode in an impact. 
         [0021]    Battery pack  140   a  may have a compact “footprint” such that it may be flexibly used in and disposed on frame  130  having different dimensions. Battery pack  140   a  can also be disposed in frame  130  to help improve directional stability (e.g., yaw acceleration). For example, battery pack  140   a  can be disposed in frame  130  such that a center of gravity of electric car  100  is in front of the center of the wheelbase (e.g., bounded by a plurality of wheels  120 ). 
         [0022]      FIG. 2A  shows battery pack  140   b  with imaginary x-, y-, and z-axis superimposed, according to various embodiments. Battery pack  140   b  can include a plurality of battery modules  210 . In a non-limiting example, battery pack  140   b  can be approximately 1000 mm wide (along x-axis), 1798 mm long (along y-axis), and 152 mm high (along z-axis), and can include thirty-six of battery modules  210 . 
         [0023]      FIG. 2B  illustrates exemplary enclosure  200  for battery pack  140   b  having a cover removed for illustrative purposes. Enclosure  200  includes tray  260  and a plurality of battery modules  210 . Tray  260  may include positive bus bar  220  and negative bus bar  230 . Positive bus bar  220  can be electrically coupled to a positive (+) portion of a power connector of each battery module  210 . Negative bus bar  230  can be electrically coupled to a negative (−) portion of a power connector of each battery module  210 . Positive bus bar  220  can be electrically coupled to positive terminal  240  of enclosure  200 . Negative bus bar  230  can be electrically coupled to negative terminal  250  of enclosure  200 . As described above with reference to  FIG. 1 , because bus bars  220  and  230  can be within structural rails  150 , they can be protected from collision damage. 
         [0024]    According to some embodiments, negative bus bar  230  and positive bus bar  220  can be disposed along opposite edges of tray  260  to provide a predefined separation between negative bus bar  230  and positive bus bar  220 . Such separation between negative bus bar  230  and positive bus bar  220  can prevent or at least reduce the possibility of a short circuit (e.g., of battery pack  140   b ) due to a deformity caused by an impact. 
         [0025]    As will be described further in more detail with reference to  FIG. 5 , battery module  210  can include at least one battery cell (details not shown in  FIG. 2A , see  FIG. 7 ). The at least one battery cell can include an anode terminal, a cathode terminal, and a cylindrical body. The battery cell can be disposed in each of battery module  210  such that a surface of the anode terminal and a surface of the cathode terminal are normal to the imaginary x-axis referenced in  FIG. 2A  (e.g., the cylindrical body of the battery cell is parallel to the imaginary x-axis). This can be referred to as an x-axis cell orientation. 
         [0026]    In the event of fire and/or explosion in one or more of battery modules  210 , the battery cells can be vented along the x-axis, advantageously minimizing a danger and/or a harm to a driver, passenger, cargo, and the like, which may be disposed in electric car  100  above battery pack  140   b  (e.g., along the z-axis), in various embodiments. 
         [0027]    The x-axis cell orientation of battery modules  210  in battery pack  140   b  shown in  FIGS. 2A and 2B  can be advantageous for efficient electrical and fluidic routing to each of battery module  210  in battery pack  140   b.  For example, at least some of battery modules  210  can be electrically connected in a series (forming string  212 ), and two or more of string  212  can be electrically connected in parallel. This way, in the event one of string  212  fails, others of string  212  may not be affected, according to various embodiments. 
         [0028]      FIG. 3  illustrates coolant flows and operation of a coolant system and a coolant sub-system according to various embodiments. As shown in  FIG. 3 , the x-axis cell orientation can be advantageous for routing coolant (cooling fluid) in parallel to each of battery modules  210  in battery pack  140   b.  Coolant can be pumped into battery pack  140   b  at ingress  310  and pumped out of battery pack  140   b  at egress  320 . A resulting pressure gradient within battery pack  140   b  can provide sufficient circulation of coolant to minimize a temperature gradient within battery pack  140   b  (e.g., a temperature gradient within one of battery modules  210 , a temperature gradient between battery modules  210 , and/or a temperature gradient between two or more of strings  212  shown in  FIG. 2A ). 
         [0029]    Within battery pack  140   b,  the coolant system may circulate the coolant, for example, to battery modules  210  (e.g., the circulation is indicated by reference numeral  330 ). One or more additional pumps (not shown in  FIG. 3 ) can be used to maintain a roughly constant pressure between multiple battery modules  210  connected in series (e.g., in string  212  in  FIG. 2A ) and between two or more of string  212 . Within each battery module  210 , the coolant sub-system may circulate the coolant, for example, between and within two half modules  410  and  420  shown in  FIG. 4  (e.g., the circulation indicated by reference numeral  340 ). 
         [0030]    In some embodiments, the coolant can enter each battery module  210  through interface  350  between two half modules  410  and  420 , in a direction (e.g., along the y- or z-axis) perpendicular to the cylindrical body of each battery cell, and flow to each cell. Driven by pressure within the coolant system, the coolant then can flow along the cylindrical body of each battery (e.g., along the x-axis) and may be collected at two (opposite) side surfaces  360 A and  360 B of the module that can be normal to the x-axis. In this way, heat can be efficiently managed/dissipated and thermal gradients minimized among all battery cells in battery pack  140   b,  such that a temperature may be maintained at an approximately uniform level. 
         [0031]    In some embodiments, parallel cooling, as illustrated in  FIG. 3 , can maintain temperature among battery cells in battery pack  140   b  at an approximately uniform level such that a direct current internal resistance (DCIR) of each battery cell can be maintained at an substantially predefined resistance. The DCIR can vary with a temperature, therefore, keeping each battery cell in battery pack  140   b  at a substantially uniform and predefined temperature can result in each battery cell having substantially the same DCIR. Since a voltage across each battery cell can be reduced as a function of its respective DCIR, each battery cell in battery pack  140   b  may experience substantially the same loss in voltage. In this way, each battery cell in battery pack  140   b  can be maintained at approximately the same capacity and imbalances between battery cells in battery pack  140   b  can be minimized, improving battery efficiency. 
         [0032]    In some embodiments, when compared to techniques using metal tubes to circulate coolant, parallel cooling can enable higher battery cell density within battery module  210  and higher battery module density in battery pack  140   b.  In some embodiments, coolant or cooling fluid may be at least one of the following: synthetic oil, for example, poly-alpha-olefin (or poly-α-olefin, also abbreviated as PAO) oil, ethylene glycol and water, liquid dielectric cooling based on phase change, and the like. 
         [0033]      FIG. 4  illustrates battery module  210  according to various embodiments. Main power connector  460  can provide power from battery cells  450  to outside of battery module  210 . Coolant can be provided to battery module  210  at main coolant input port  480 , receive/transfer heat from battery module  210 , and be received at main coolant output port  470 . In some embodiments, battery module  210  can include two half modules  410  and  420 , each having respective enclosure  430 . Enclosure  430  may be made using one or more plastics having sufficiently low thermal conductivities. Respective enclosures  430  of each of two half modules  410  and  420  may be coupled with each other to form the housing for battery module  210 . 
         [0034]      FIG. 4  includes view  440  of enclosure  430  (e.g., with a cover removed). For each of half modules  410 ,  420  there is shown a plurality of battery cells  450  oriented (mounted) horizontally (see also  FIGS. 5 and 8 ). By way of non-limiting example, each half module can include one hundred four of battery cells  450 . By way of further non-limiting example, eight of battery cells  450  can be electrically connected in a series (e.g., the staggered column of eight battery cells  450  shown in  FIG. 4 ), with a total of thirteen of such groups of eight battery cells  450  electrically connected in series. By way of additional non-limiting example, the thirteen groups (e.g., staggered columns of eight battery cells  450  electrically coupled in series) can be electrically connected in parallel. This example configuration may be referred to as “8S13P” (8 series, 13 parallel). In some embodiments, the 8S13P electrical connectivity can be provided by current carrier  510 , described further below in relation to  FIGS. 5 and 6 . Other combinations and permutations of battery cells  450  electrically coupled in series and/or parallel may be used. 
         [0035]      FIG. 5  depicts a view of half modules  410 ,  420  without enclosure  430  in accordance with various embodiments. Half modules  410  and  420  need not be the same, for example, they may be mirror images of each other in some embodiments. Half modules  410  and  420  can include a plurality of battery cells  450 . The plurality of battery cells  450  can be disposed between current carrier  510  and blast plate  520  such that an exterior side of each of battery cells  450  is not in contact with the exterior sides of other (e.g., adjacent) battery cells  450 . In this way, coolant can circulate among and between battery cells  450  to provide submerged, evenly distributed cooling. In addition, to save the weight associated with coolant in areas where cooling is not needed, air pockets can be formed using channels craftily designed in space  530  between current carrier  510  and blast plate  520  not occupied by battery cells  450 . 
         [0036]    Coolant can enter half modules  410 ,  420  through coolant intake  540 , be optionally directed by one or more flow channels, circulate among and between the plurality of battery cells  450 , and exits through coolant outtake  550 . In some embodiments, coolant intake  540  and coolant outtake  550  can each be male or female fluid fittings. In some embodiments, coolant or cooling fluid is at least one of: synthetic oil such as poly-alpha-olefin (or poly-a-olefin, abbreviated as PAO) oil, ethylene glycol and water, liquid dielectric cooling based on phase change, and the like. Compared to techniques using metal tubes to circulate coolant, submerged cooling improves a packing density of battery cells  450  (e.g., inside battery module  210  and half modules  410 ,  420 ) by 15%, in various embodiments. 
         [0037]      FIGS. 6A and 6B  depict current carrier  510 ,  510 A according to various embodiments. Current carrier  510 ,  510 A can be generally flat (or planar) and can comprise one or more layers (not shown in  FIGS. 6A and 6B ), such as a base layer, a positive power plane, a negative power plane, and signal plane sandwiched in-between dielectric isolation layers (e.g., made of polyimide). In some embodiments, the signal plane can include signal traces and be used to provide battery module telemetry (e.g., battery cell voltage, current, state of charge, and temperature from optional sensors on current carrier  510 ) to outside of battery module  210 . 
         [0038]    As depicted in  FIG. 6B , current carrier  510 A can be a magnified view of a portion of current carrier  510 , for illustrative purposes. Current carrier  510 A can be communicatively coupled to each of battery cells  450 , for example, at separate (fused) positive (+) portion  630  and separate negative (−) portion  640  which may be electrically coupled to the positive power plane and negative power plane (respectively) of current carrier  510 A, and to each cathode and anode (respectively) of battery cell  450 . In some embodiments, positive (+) portion  630  can be laser welded to a cathode terminal of battery cell  450 , and negative (−) portion  640  can be laser welded to an anode terminal of battery cell  450 . In some embodiments, the laser-welded connection can have on the order of 5 milli-Ohms resistance. In contrast, electrically coupling the elements using ultrasonic bonding of aluminum bond wires can have on the order of 10 milli-Ohms resistance. Laser welding advantageously can have lower resistance for greater power efficiency and take less time to perform than ultrasonic wire bonding, which can contribute to greater performance and manufacturing efficiency. 
         [0039]    Current carrier  510 A can include fuse  650  formed from part of a metal layer (e.g., copper, aluminum, etc.) of current carrier  510 A, such as in the positive power plane. In some embodiments, fuse  650  can be formed (e.g., laser etched) in a metal layer (e.g., positive power plane) to dimensions corresponding to a type of low-resistance resistor and acts as a sacrificial device to provide overcurrent protection. For example, in the event of thermal runaway of one of battery cell  450  (e.g., due to an internal short circuit), the fuse may “blow,” breaking the electrical connection to battery cell  450  and electrically isolating battery cell  450  from current carrier  510 A. Although an example of a fuse formed in the positive power plane was provided, a fuse may additionally or alternatively be a part of the negative power plane. 
         [0040]    Additional thermal runaway control can be provided in various embodiments by scoring on end  740  (identified in  FIG. 7 ) of battery cell  450 . The scoring can promote rupturing to effect venting in the event of over pressure. In various embodiments, all battery cells  450  may be oriented to allow venting into blast plate  520  for both half modules. 
         [0041]    In some embodiments, current carrier  510  can be comprised of a printed circuit board and a flexible printed circuit. For example, the printed circuit board may variously comprise at least one of copper, FR-2 (phenolic cotton paper), FR-3 (cotton paper and epoxy), FR-4 (woven glass and epoxy), FR-5 (woven glass and epoxy), FR-6 (matte glass and polyester), G-10 (woven glass and epoxy), CEM-1 (cotton paper and epoxy), CEM-2 (cotton paper and epoxy), CEM-3 (non-woven glass and epoxy), CEM-4 (woven glass and epoxy), and CEM-5 (woven glass and polyester). By way of further non-limiting example, the flexible printed circuit may comprise at least one of copper foil and a flexible polymer film, such as polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polyetherimide (PEI), along with various fluoropolymers (FEP), and copolymers. 
         [0042]    In addition to electrically coupling battery cells  450  to each other (e.g., in series and/or parallel), current carrier  510  can provide electrical connectivity to outside of battery module  210 , for example, through main power connector  460  ( FIG. 4 ). Current carrier  510  may also include electrical interface  560  ( FIGS. 5, 6A ) which transports signals from the signal plane. Electrical interface  560  can include an electrical connector (not shown in  FIG. 5, 6A ). 
         [0043]      FIG. 7  shows battery cell  450  according to some embodiments. In some embodiments, battery cell  450  can be a lithium ion (li-ion) battery. For example, battery cell  450  may be an 18650 type li-ion battery having a cylindrical shape with an approximate diameter of 18.6 mm and approximate length of 65.2 mm. Other rechargeable battery form factors and chemistries can additionally or alternatively be used. In various embodiments, battery cell  450  may include can  720  (e.g., the cylindrical body), anode terminal  770 , and cathode terminal  780 . For example, anode terminal  770  can be a negative terminal of battery cell  450  and cathode terminal  780  can be a positive terminal of battery cell  450 . Anode terminal  770  and cathode terminal  780  can be electrically isolated from each other by an insulator or dielectric. 
         [0044]      FIG. 8  is a cross sectional view of half module  800  for illustrative purposes. In some embodiments, half module  800  can be half modules  410 ,  420  ( FIG. 5 ). Half module  800  can comprise current carrier  510  ( FIGS. 5, 6A, and 6B ), blast plate  520  ( FIG. 5 ), battery cells  450  ( FIGS. 5 and 7 ), and retainer  810  disposed between current carrier  510  and blast plate  520 . 
         [0045]    Each of battery cells  450  can include an exterior surface having coating  830 . A length of battery cells  450  having coating  830  can be denoted by reference character “b.” Conversely, a length of battery cells  450  not having coating  830  can be denoted by reference character “a.” For example, “b” can be in a range of 50%-90% of the length of battery cells  450 . In some embodiments, coating  830  can be an electrical insulator providing (dielectric) isolation (e.g., extremely low electrical conductivity or high electrical resistance, such as a dielectric constant or relative permittivity (e.g., ε or κ) less than 15 and/or a volume resistance greater than 10 14  ohm·cm) between each of battery cells  450  (e.g., such that battery cells  450  do not short out). In various embodiments, coating  830  can additionally or alternatively provide high thermal conductivity (e.g., greater than 5 W/m·° K) to each of battery cells  450 , which may facilitate transfer of heat from battery cells  450  to a fluid, such as a liquid coolant. For example, coating  830  may comprise one or more of aluminum oxide (Al 2 O 3 ), diamond powder based materials, boron nitride (BN), and the like. By way of further non-limiting example, coating  830  can be applied to an exterior surface of battery cells  450  using at least one of: electrophoretic deposition (EPD) (e.g., electrocoating, e-coating, cathodic electrodeposition, anodic electrodeposition, and electrophoretic coating/painting), dipping, thermal spraying (e.g., plasma spraying), and the like. 
         [0046]    In some embodiments, the exterior surface of battery cells  450  having coating  830  can be disposed in submersion area  820  of half module  800 A, and submersion area  820  can have a liquid coolant disposed therein. In other words, a portion of battery cells  450  having coating  830  can be submerged in a liquid coolant. For example, submersion area can be a space or volume disposed between retainer  810  and blast plate  520 . By way of further non-limiting example, the coolant can be ethylene glycol and water. In comparison to full submersion, partial submersion as illustrated in  FIG. 8A  can offer the advantages of lower weight, due at least in part to a lower volume of coolant in each half module  800 A. Ethylene glycol can offer the advantage of higher heat/thermal capacity and transfer heat more efficiently, compared to some other coolants. 
         [0047]    In some embodiments, the exterior surface of battery cells  450  not having coating  830  can be disposed in non-submersion area  840 , and non-submersion area  840  may have a substance other than liquid coolant disposed therein (e.g., fluid such as air, which is substantially nitrogen gas (˜78%) and oxygen gas (˜21%)). In other words, a portion of battery cells  450  not having coating  830  may not be submerged in a liquid coolant. For example, non-submersion area can be a space or volume disposed between current carrier  510  and retainer  810 . 
         [0048]    Retainer  810  can hold battery cells  450  in a fixed position and separate submersion area  820  from non-submersion area  840 . In various embodiments, submersion area  820  can be under pressure, for example, from (circulation) pumping the coolant. In some embodiments, the coolant pressure can be on the order of less than 5 pounds per square inch (PSI), for example, about 0.7 PSI. 
         [0049]    Retainer  810  can form a seal (e.g., analogous to an o-ring) around a section or portion of battery cells  450  such that the coolant does not flow/move from submersion area  820  to non-submersion area  840 . For example, retainer  810  can comprise an elastomer (e.g., rubber). In some embodiments, retainer  810  can be coupled to an exterior surface of battery cells  450  having coating  830 , not having coating  830 , or partially having coating  830  and partially not having coating  830 . 
         [0050]    Additionally or alternatively, a surface of retainer  810  in fluidic contact with non-submersion area  840  may be potted (e.g., filled with a solid or gelatinous compound (e.g., thermo-setting plastics, silicone rubber gels, etc. to exclude the coolant). In various embodiments, areas near and/or at where current carrier  510  can be electrically coupled to battery cells  450  can be potted (e.g., to prevent electrical shorts). 
         [0051]      FIG. 9  is a cross sectional view of half module  900  for illustrative purposes. In some embodiments, half module  900  can be half modules  410 ,  420  ( FIGS. 4 and 5 ). As shown in  FIG. 9 , an exterior surface of battery cells  450  ( FIGS. 4, 5, 7, and 8 ) can be substantially fully covered by coating  830  ( FIG. 8 ) (e.g., except near and/or at end  740  of battery cells  450  which includes cathode terminal  780  and anode terminal  770  ( FIG. 7 )). For example, submersion area  820  may run substantially the full length of battery cells  450 . In other words, battery cells  450  are substantially fully submerged in the coolant (e.g., except near and/or at end  740  of battery cells  450 ). In some embodiments, the coolant substantially covers 98% of the battery cells  450 . In another embodiment, the coolant substantially covers between 92% and 98% of the battery cells  450 . In some embodiments, the coolant may flow/circulate through flow channels  910  in retainer  810  and/or current carrier  510  ( FIGS. 5, 6A, and 6B  ( 510 A)). In various embodiments, areas—near where current carrier  510  can be electrically coupled to battery cells  450  and/or where current carrier  510  can be electrically coupled to battery cells  450 —can be potted (e.g., filled with a solid or gelatinous compound, such as thermo-setting plastics, silicone rubber gels, etc., to exclude the coolant, to prevent electrical shorts, and the like). 
         [0052]    As would be readily appreciated by one of ordinary skill in the art, various embodiments described herein may be used in additional applications, such as in energy-storage systems for wind and solar power generation. Other applications are also possible. 
         [0053]    The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Exemplary embodiments were chosen and described in order to best explain the principles of the present disclosure and its practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.