Patent Publication Number: US-2022223947-A1

Title: Puncture resistant shield of a battery containment system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority benefit of U.S. Provisional Application Ser. No. 63/047,945 filed 3 Jul. 2020, the contents of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention in general relates to a high strength, light weight battery containment system and in particular to a high strength, light weight puncture resistant shield of such a containment system that provides additional protection to the containment system from road debris. 
     BACKGROUND OF THE INVENTION 
     Weight savings in the automotive, transportation, aerospace, and logistics-based industries has been a major focus in order to make more fuel-efficient vehicles both for ground and air transport. In order to achieve these weight savings, light weight composite materials have been introduced to take the place of metal structural and surface body components and panels. Composite materials are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. A composite material may be preferred for reasons that include materials which are stronger, lighter, or less expensive when compared to traditional materials of steel or aluminum. Still another advantage over metals is reduced corrosion, leading to longer operational life and reduced maintenance costs. 
     Composites typically have two constituent materials: matrix and reinforcement. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. A synergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials allows the designer of the product or structure to choose an optimum combination. 
     The use of fiber inclusions to strengthen a matrix is well known to the art. Well established mechanisms for the strengthening of a matrix include slowing and elongating the path of crack propagation through the matrix, as well as energy distribution associated with pulling a fiber free from the surrounding matrix material. In the context of sheet molding composition (SMC) formulations, bulk molding composition (BMC) formulations, and resin transfer molding (RTM) fiber strengthening has traditionally involved usage of chopped glass fibers, while carbon fibers are known to be high strength and low weight reinforcements. 
     Weight savings are particularly important for electric and hybrid vehicles powered with energy cells employing battery technologies in order to achieve greater vehicle driving range per charge. However, unique problems associated with some components of electric and hybrid vehicles have hindered the ability to use composite materials for some applications on hybrid or electric vehicles. For example, batteries of electric and hybrid vehicles present unique safety considerations owing to the high voltages of the batteries, chemicals employed in the battery technologies, combustion and fire risks associated with the batteries, and potential fume encounters if the batteries are broken or damaged. Therefore, batteries of electric and hybrid vehicles generally require protective containers designed to shield batteries from forces they may otherwise experience during an impact or crash event. 
     Generally, such protective containers are high strength boxes formed of welded metals, which are heavy, prone to corrosion, and have been found to be water penetrable at least at the welds. Attempts have been made to form protective battery containers from composite materials to reduce the weight of such containers. However, such containers are usually joined with metal bolts, which require additional machining of through holes in the composite material of the container, which is difficult because of the high strength of the material through which the holes must be drilled, placement of the bolts in the through holes, and securing of the bolts with nuts, leading to complex manufacturing techniques, slow manufacturing throughputs, and high manufacturing costs. Additionally, the designs of typical battery containment boxes are generally focused on protecting batteries from side impact forces they may experience during an impact or crash event, while failing to provide sufficient protection of the batteries contained therein from other potential damage such as an impact or impalement of road debris during normal operating conditions. 
     Thus, there exists a need for a puncture resistant shield for use with a battery containment system that is light weight and resistant to corrosion, while improving the safety performance of the battery containment system by providing greater impact and impalement protection as compared to conventional vehicle components. 
     SUMMARY OF THE INVENTION 
     A puncture resistant shield is provided for use with a battery containment system of a vehicle. The puncture resistant shield includes a shield body portion configured to underlie the battery containment system, where the shield body portion has a first surface and an oppositely opposed second surface both bounded by a first end and a second end and a first side and a second side that each extend from the first end to the second end. A first ramp extends from the first end of the shield body portion at a first angle. The puncture resistant shield is configured to be attached to the battery containment system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is further detailed with respect to the following drawings that are intended to show certain aspects of the present invention but should not be construed as a limit on the practice of the present invention. 
         FIG. 1  is a top perspective view of a puncture resistant shield according to embodiments of the present invention attached to a battery containment system; 
         FIG. 2  is a bottom perspective view of the puncture resistant shield attached to the battery containment system of  FIG. 1 ; 
         FIG. 3  is a top view of the puncture resistant shield attached to the battery containment system of  FIG. 1 ; 
         FIG. 4  is a cross sectional view of the puncture resistant shield attached to the battery containment system cut along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a detailed view of the puncture resistant shield attached to the battery containment system as shown in section  5  of  FIG. 4 ; 
         FIG. 6  is a cross sectional view of the puncture resistant shield attached to the battery containment system cut along line  6 - 6  of  FIG. 3 ; 
         FIG. 7  is a cross sectional view of the puncture resistant shield attached to the battery containment system cut along line  7 - 7  of  FIG. 3 ; 
         FIG. 8  is an exploded perspective view of a puncture resistant shield according to embodiments of the present invention and a battery containment system; 
         FIG. 9  is a cross sectional view of the puncture resistant shield assembled with the battery containment system of  FIG. 8 ; 
         FIG. 10  is a cross sectional view of a puncture resistant shield according to embodiments of the present invention assembled with a cover of a battery containment system; 
         FIG. 11A  is a bottom view of a cover of a battery containment system to which a shield of the present invention may be attached; 
         FIG. 11B  is a top view of a shield according to embodiments of the present invention; 
         FIG. 12A  is a bottom view of a cover of a battery containment system to which a shield of the present invention may be attached; 
         FIG. 12B  is a top view of a shield according to embodiments of the present invention; 
         FIG. 13A  is a bottom view of a shield according to embodiments of the present invention assembled with a battery containment system; 
         FIG. 13B  is a bottom view of a shield according to embodiments of the present invention assembled with a battery containment system; 
         FIG. 13C  is a bottom view of a shield according to embodiments of the present invention assembled with a battery containment system; and 
         FIGS. 14A-14D  are side views of joiner clips used to attach a shield to a battery containment system according to embodiments of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention has utility as a puncture resistant shield for use with a battery containment system that is light weight and resistant to corrosion, while improving the safety performance of the battery containment system by providing greater impact and impalement protection as compared to conventional vehicle components. The inventive puncture resistant shield also has utility in that it may be used with existing battery containment systems as an aftermarket installation to increase protection of the batteries contained therein or may be designed for use with new manufactured battery containment systems. 
     Battery cases and containment systems are getting bigger year by year due to the increase in amount of batteries installed. For example, the length of a typical battery case in a vehicle width direction is often 70% or more with respect to the vehicle width, and sometimes 80% or more. For this reason, when a large battery case is mounted in the lower part of the vehicle, a larger load is input to the battery case at the time of a collision rather than previous battery cases. Given the position and size of a battery case on vehicles, the batteries are susceptible to impalement from road or collision debris. Therefore, according to embodiments, the inventive penetration resistant shield is designed to be used with a battery containment case or system to provide resistance to such impalements in order to protect the batteries. 
     The present invention will now be described with reference to the following embodiments. As is apparent by these descriptions, this invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. For example, features illustrated with respect to one embodiment can be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from the embodiment. In addition, numerous variations and additions to the embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure, which do not depart from the instant invention. Hence, the following specification is intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations, and variations thereof. 
     It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 
     Unless indicated otherwise, explicitly or by context, the following terms are used herein as set forth below. As used in the description of the invention and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”). 
     Referring now to the figures, a puncture resistant shield  40  for use with a battery containment system  10  of a vehicle is shown. According to embodiments, the puncture resistant shield  40  includes a shield body portion  42  that has a first surface  44  and an oppositely opposed second surface  46  both bounded by a first end  48  and a second end  50  and a first side  52  and a second side  54  that each extend from the first end  48  to the second end  50 . The puncture resistant shield  40  additionally includes a first ramp  56  extending from the first end  48  of the shield body portion  42  at a first angle α, which according to embodiments is an angle of 10 to 90 degrees. The puncture resistant shield  40  is configured to be attached to the battery containment system  10  such that the shield body portion  42  underlies the battery containment system  10 . 
     As shown in the figures, a battery containment system  10  with which embodiments of the inventive puncture resistant shield  40  are used generally includes a tray  20  for containing a plurality of batteries  12  and a cover  30 . Further details regarding features of a battery containment system  10  are described in co-pending International Patent Application No. PCT/US2020/031750, which is hereby incorporated by reference and are additionally described in part herein. 
     According to embodiments, the ramp  56  that extends from the first end  48  of the shield body portion  42  is integrally formed with the shield body portion  42 . According to embodiments, the ramp  56  extends the entire length of the first end  48  of the shield body portion  42 , and therefore the ramp  56  extends from the first end  48  of the shield body portion  42  from the first side  52  to the second side  54  of the shield body portion  42 . According to embodiments, the puncture resistant shield  40  is configured to be attached to a battery containment system  10  such that first ramp  56  is positioned towards a front of the vehicle. According to embodiments, first ramp  56  is configured to be angled upwards towards said battery containment system  10  when said puncture resistant shield  40  is attached to the battery containment system  10 . Such positioning and orientation of the first ramp  56  of the shield  40  allows the ramp  56  to further protect batteries  12  contained in the containment system  10  by deflecting road and crash debris that the vehicle may encounter when traveling in a forward direction. According to embodiments, the shield  40  additionally includes at least one additional ramp  56 ′ extending from at least one of the second end  50 , the first side  52 , and the second side  54  of the shield body portion  42  at a second angle β, which according to embodiments is the same angle as the first angle α. 
     According to certain inventive embodiments, the shield  40  is formed of reinforced sheet molding compound (SMC), a phenolic-SMC, epoxy, acrylonitrile butadiene styrene (ABS), polycarbonate, random-oriented fiber reinforced thermoplastic resin (FRTP), steel, or aluminum. Sheet molding compound (SMC) or sheet molding composite is a ready to mold fiber-reinforced polyester material primarily used in compression molding. SMC is a reinforced composite material that is manufactured by dispersing long strands (20-60 mm) of chopped glass fibers in a matrix of polyester resin. It is appreciated that fibers with long range order are also operative herein and include woven mats, continuous fibers, or sheet forms. Thermoplastic materials operative herein amenable to functioning as a fiber matrix illustratively include: poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS), polyamides, polylactides, polybenzimidazoles, polycarbonates, polyether sulfones, polyethylene, polypropylene, polystyrene, polyvinyl chloride, or block copolymers of any one of the aforementioned constituting the majority by monomer number. Reinforcing fibers and fillers operative herein illustratively include carbon fibers, glass fibers, aramid fibers, cellulosic fibers, or a combination thereof. In some inventive embodiments, the chopped fiber is glass fiber, alone or in combination with other types of fiber or reinforcing fillers. According to embodiments, the shield  40  is formed of aramid fiber reinforced SMC, which is particularly well suited for resisting impalement by crash or road debris. 
     As shown in  FIG. 6 , according to embodiments, the puncture resistant shield  40  is formed to have corrugations  58 . According to embodiments, the corrugations  58  have a repeating shape of any of: an open semi hexagon, an open semi-circle, an open semi oval, an open triangle, an open semi square, an open semi rectangle, or a sine wave. According to embodiments, the corrugations are formed in the material of the shield  40  by a stamping process, a bending process, or by a molding process. 
     According to embodiments, the shield  40  may have one or more coatings. The coating illustratively includes materials that impart fire resistance, are phenolic in nature, electromagnetic interference-radiofrequency interference (EMI-RFI) resistance, or a combination of such coatings. It is appreciated that coating as used in this context is intended to include separate layers of material that are applied as a sheet material to a substrate of the shield  40 . That is, according to embodiments, the shield  40  is coated in a fire resistant, or a fire-retardant material. A fire-resistant material is one that is designed to resist burning and withstand heat and provide insulation to the substrate, while a fire-retardant material is designed to burn slowly and reduce the rate of flame spread. Intumescent fire-resistant materials work by expanding their volume from 15 to 30 times and generating an ash-like char layer that erodes as fire exposure continues. Expansion then occurs again with the number of times the process repeats itself dependent upon the thickness of the coating. For example, such fire resistant or fire retardant materials for coating the shield  40  include any of the following: silicone, casein or vinyl resins, aluminum trihydrate or antimony oxide, ammonium polyphosphate, pentaerythritol, melamine derivatives, boric acid (H 3 BO 3 ) and borax (Na 2 B 4 O 7 .10H 2 O), disodium octaborate tetrahydrate (Na 2 B 8 O 13 .4H 2 O), dicyandiamide-formaldehyde-phosphoric acid, melamine-dicyandiamide-formaldehyde-phosphoric acid, poly(n-vinylpyrolidone), colloidal silica, magnesium hydroxide (MDH), monoammonium phosphate (MAP), aluminum hydroxide (ATH), carbonates and hydrogen carbonates, potassium carbonate, Na 2 WO 4 , Na 2 SnO 3 , Na 2 MoO 4 , ammonium polyphosphate, pentaerythritol, melamine, expandable graphite, or combinations thereof. Phenolic resins operative herein illustratively includes epoxy phenolic resins, and phenol formaldehyde resins that impart corrosion resistance and a mar resistance surface relative to the underlying substrate of the shield  40 . EMI-RFI shielding coatings operative herein illustratively include nickel coated glass mat; carbon fiber matting; copper or nickel paint; various metal foils, such as aluminum, nickel, iron, copper, and alloys thereof; and or combinations thereof with the proviso that the EMI-RFI shielding is grounded so as to function as a Faraday cage. It is further appreciated that coatings in the form of sheets are readily applied as an underlying sheet below an inventive shield  40  or are included as filler in the materials that are used to form the shield  40 . 
     According to embodiments, the puncture resistant shield  40  is configured to be attached to the battery containment system  10  using an adhesive  60  applied between the first surface  44  of the shield body portion  42  and a lower surface  22  of the battery containment system  10 , which for example is the lower surface of the tray  20 . According to embodiments, the puncture resistant shield  40  is configured to be attached to the battery containment system  10  by a plurality of fasteners  62 ,  62 ′ that extend through said shield body portion  42  through a plurality of through holes formed in said shield body portion  42 . According to embodiments, such through holes may be formed in the material of the shield body portion  42  when the SMC material is laid up or may be formed subsequently by a drilling or stamping process. The plurality of fasteners  62  for example may include screws or bolts that are inserted through the shield body portion  42  such that the threaded end is secured within the battery containment system  10 . Alternatively, the plurality of fasteners  62 ′ for example may include bolts that have their heads embedded in the battery containment system and their threads exposed downward for insertion through the holes  64  formed in the shield body portion  42 . In such an instance, nuts  66  or other suitable securing devices are installed onto the threaded portions of the embedded bolts  62 ′ to secure the shield  40  to the battery containment system  10 . 
     According to embodiments such as that shown in  FIGS. 8-13 , the shield  40  additionally includes a shield flange  86  that extends from the shield body portion  42 . As shown in  FIG. 8 , the shield body portion  42  of the shield  40  may include a plurality of ramps  56 ,  56 ′ from which the shield flange  86  extends such that the flange and the shield body portion  42  are in separate planes. According to embodiments, the flange  86  of the shield  40  extends from the shield body portion  42  such that the shield  40  is a substantially planar component. As noted above, shield body portion  42  of the shield  40  is configured to underlie the tray  20  of the battery containment system  10 . The flange  86  of the shield  40 , which extends from the shield body portion  42  or from the ramp  56  or additional ramp  56 ′, is configured to extend beyond the tray  20  of the battery containment system  10 . Additionally, the flange  86  of the shield  40  is configured to engage a flange  32  of the cover  30  of the battery containment system  10 . 
     As shown in  FIG. 8 , the cover  30  includes wall  34  between the cover flange  32  and the cover body portion  36 , making the cover flange  32  and the cover body portion  36  in different planes. The shield  40  is positioned under the tray  20 . As shown in  FIG. 8 , the shield  40  includes ramps  56 ,  56 ′ that extend from the first end  48 , second end  50 , first side  52 , and second side  54  of the body portion  42  of the shield  40  and from which the shield flange  86  extends. The cover flange  32  and the shield flange  86  are configured to engage one another in an abutting relationship and be joined together by a joiner clip  100 , as shown in  FIG. 9 . 
       FIG. 10  shows a cross sectional view of a cover  30  of a battery containment system  10  and a shield  40  of the present invention joined together by a joiner clip  100 . In  FIG. 10 , the tray  20  and batteries  12  of the battery containment system  10  is not shown for clarity. As shown, a joiner clip  100  having a C-shaped cross section joins the cover  30  and the shield  40  together. The cover  30 , the shield  40 , and the joiner clip  100  are configured to be assembled around the tray  20  of a battery containment system  10  in such a way as to attach the inventive shield  40  to the containment system  10 . The puncture resistant shield  40  thereby provides impalement resistance, impact resistance to the battery containment system  10  and the batteries  12  contained therein. 
     According to embodiments, the flange  32  of the cover and the shield flange  86  of the shield  40  are configured to engage one another in abutting contact such that the cover  30  and the shield  40  define a cavity  126  therebetween. The cavity  126  is configured to receive and contain the tray  20 , as described above. The joiner clip  100  is configured to engage the cover flange  32  and the shield flange  86  to join the cover  30  and the shield  40  together. 
     According to embodiments, the cover flange  32  surrounds the perimeter of the cover  30 . Similarly, according to embodiments, the shield flange  86  surrounds the perimeter of the shield  40 . According to embodiments, such as those shown in  FIGS. 11A, 11B, 13A, and 13B , the flanges  32 ,  86  are each continuous in that they entirely cover the perimeter of the cover  30  and shield  40 , respectively. According to other embodiments, such as those shown in  FIGS. 12A, 12B, and 13C , the flanges  32 ,  86  are each made up of separate and discrete flange portions that non-continuously surround the cover  30  and shield  40 , respectively. According to embodiments, in which the flanges  32 ,  86  are continuous and entirely surround the cover  30  and shield  40 , the joiner clip  100  is either a single continuous joiner clip  100 ′, as shown in  FIG. 13A , that also entirely surrounds the cover  30  and shield  40 , or the joiner clip is a plurality of separate and discrete joiner clips  100 ″, as shown in  FIG. 13B , positioned at separate locations along the cover flange  32  and the shield flange  86  to non-continuously surround the cover  30  and the shield  40 . According to embodiments, in which the flanges  32 ,  86  are each made up of separate and discrete flange portions that non-continuously surround the respective cover  30  and shield  40 , the joiner clip  100  is a plurality of separate and discrete joiner clips  100 ″ positioned at separate locations along the cover flange  32  and the shield flange  86  to non-continuously surround the cover  30  and shield  40 , as shown in  FIG. 13C . 
     As shown in  FIGS. 10 and 14A-14D , the joiner clip  100  includes a base section  132  and a pair of jaws  134 ,  134 ′extending from the base  132  section each jaw  134 ,  134 ′ of the pair of jaws having a free end  136 ,  136 ′, respectively. According to embodiments, the base section  132  is curved or square, as shown in  FIGS. 14C-14D and 14A-14B , respectively. According to embodiments, one or both of the jaws  134 ,  134 ′ are straight or feature a curve such that the free ends  136 ,  136 ′ of each of the jaws  134 ,  134 ′ are flared away from one another, such as shown in  FIGS. 14A and 14C-14D and 14B , respectively. The flared free ends  136 ,  136 ′ facilitate easy application of the joiner clip  100  onto the flanges  32 ,  86 . That is, to apply the joiner clip  100 , the flanges  32 ,  86  are positioned between the free ends  136 ,  136 ′ of the joiner clip and the joiner clip  100  is pushed or pounded onto the flanges  32 ,  86 , thereby eliminating the need for a special tool for separating the jaws  134 ,  134 ′. The flared free ends  136 ,  136 ′ also reduce wear on the composite material of the flanges  32 ,  86  by ensuring that the free ends  136 ,  136 ′ do not rub on the flanges  32 ,  86 . 
     According to embodiments, the free ends  136 ,  136 ′ of each of the jaws  134 ,  134 ′ are biased toward one another. Thus, when the joiner clip  100  is engaged with the flanges  32 ,  86 , such that the flanges  32 ,  86  are positioned between the jaws  134 ,  134 ′ of the joiner clip  100 , the joiner clip applies a compressive force to the cover flange  32  and the shield flange  86  to join the cover  30  and the shield  40  together. According to embodiments, the joiner clip is formed of a metal, such as spring steel, a thermoplastic, or an elastomeric material. Embodiments in which the joiner clip is formed of an elastomeric material provide the additional benefit of sealing the cover  30  and shield  40  while also joining them together. According to embodiments, the joiner clip  100  also includes at least on barb  138  positioned on an inner surface of at least one of the jaws  134 ,  134 ′. The barb or barbs  138  are configured to dig into the composite material of the flanges  32 ,  86  or may engage with a groove  140  formed in the flanges to prevent the joiner clip  100  from falling off of or being easily removed from the flanges  32 ,  86 . 
     According to embodiments, the shield  40  also includes a barrier material  128  positioned between the cover flange  32  and the shield flange  86 . According to embodiments, the barrier material  128  acts as a seal and/or a connector between the cover  30  and the shield  40  to limit movement or slippage between the cover  30  and the shield  40 . According to embodiments, the barrier material  128  is any of an adhesive, a gasket, or a connector. In some embodiments, such as that shown in  FIG. 10 , at least one of the cover flange  32  and shield flange  86  define a channel  130  that is configured to receive and retain the barrier material  128 . The channel  130  may be a continuous channel or may be a plurality of discrete channels spaced along the length of the flanges  32 ,  86  at spaced apart positions. According to embodiments in which at least one of the flanges  32 ,  86  includes a channel, the barrier material  128  is placed in the channel  130  before the flanges  32 ,  86  are brought into contact with one another. According to embodiments, in which both flanges  32 ,  86  define a channel  130  therein, the barrier material  128  is placed in the channel  130  of for example the cover flange  32  and then the shield flange  86  is brought into contact with the cover flange  32  and the barrier material. In such embodiments, the barrier material  128  can be used as a position locator for ensuring that the cover flange  32  and shield flange  86  are properly positioned relative to one another. Additionally, once assembled, the barrier material  128  ensures that the cover  30  and the shield  40  remain properly positioned relative to one another during use, by preventing slippage, which in turn reduces wear on the parts. It will also be understood that when the barrier material  128  is a gasket, the barrier material may act to seal the cover  30  and shield  40  in water tight engagement and act to locate and retains the cover  30  and shield  40  relative to one another. 
     Patent documents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These documents and publications are incorporated herein by reference to the same extent as if each individual document or publication was specifically and individually incorporated herein by reference. 
     The foregoing description is illustrative of particular embodiments of the invention but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.