WO2024144777A1

WO2024144777A1 - Enclosures via dual parison blow molding with intermediate layer of long glass/fiber reinforcement

Info

Publication number: WO2024144777A1
Application number: PCT/US2022/054217
Authority: WO
Inventors: Jonathan HOLTZ; Justin BEKKER; Moez Haouala; Albert Boecker; Andy SUTHERLAND; Cletus J. THIELEN
Original assignee: Ti Group Automotive Systems, Llc
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2024-07-04

Abstract

A method of forming a reinforced hollow structure includes the steps of providing an initially open blow mold and positioning a 1st parison therein; closing the mold and providing a pressurized fluid that causes the 1st parison to expand; allowing the 1st parison to form the shape of an outer wall defining the periphery of the reinforced hollow structure; opening the mold and separating the outer wall into at least two sections; inserting a fiber layer into the mold; positioning a 2nd parison in the mold; closing the mold and providing a pressurized fluid that causes the 2nd parison to expand; allowing the 2nd parison to form the shape of an inner wall securing the fiber layer between the inner and outer walls of the reinforced hollow structure; and opening the mold to remove the reinforced hollow structure in at least two parts (Part 1 & Part 2).

Description

ENCLOSURES VIA DUAL PARISON BLOW MOLDING WITH INTERMEDIATE LAYER OF LONG GLASS/FIBER REINFORCEMENT

FIELD

[0001] The invention relates to an enclosure formed via dual parison blow molding with an intermediate layer of a long glass/fiber reinforcement. This enclosure may be, for example, a high voltage battery enclosure (HVBE) for use in providing protection and/or thermal management for a battery or battery module and/or a battery pack.

BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and several definitions for terms used in the present disclosure and may not constitute prior art.

[0003] Conventional high voltage battery enclosures (HVBE) are commonly formed from one or more metals, such as steel or aluminum. These metal enclosures generally comprise many different sections due to the manufacturing constraints associated with metallic parts. The joining of these metallic parts together requires a high amount of specialized fastening or joining techniques and/or equipment in order to ensure structural stability and adequate sealing. These metal enclosures are heavy and reduce the range/efficiency of the battery in hybrid (HEV) and electric (EV) vehicles.

[0004] Some conventional enclosures may be formed from plastic resins that include a plurality of discontinuous or short (chopped) fibers dispersed within the resin component. Although these plastic enclosures are lighter in weight than the metal enclosures, the manufacturing of these enclosures is constrained by higher cost of the base material and the type of processes that can be used due to the higher tool wear caused by the fibers dispersed in the plastic resin.

SUMMARY

[0005] An objective of the present disclosure is to overcome the aforementioned disadvantages and to provide a method of manufacturing a reinforced hollow structure. In this respect, the method of the present disclosure generally comprises providing an initially open blow mold and positioning a 1^st parison therein; closing the mold and providing a pressurized fluid that causes the 1^st parison to expand; allowing the 1^st parison to form the shape of an outer wall that defines the periphery of the reinforced hollow structure; opening the mold and separating the outer wall into at least two sections; inserting a fiber layer into the mold; positioning a 2^nd parison in the mold; closing the mold and providing a pressurized fluid (gas or liquid) that causes the 2^nd parison to expand; allowing the 2^nd parison to form the shape of an inner wall that secures the fiber layer between the inner wall and the outer wall, thereby forming the reinforced hollow structure; and opening the mold to remove the reinforced hollow structure and separating said reinforced hollow structure into at least two parts (Part 1 & Part 2).

[0006] When desirable or necessary based on the requirements of the application, the method may further comprise inserting one or more components into the mold prior to the positioning of the 1^st parison and/or prior to positioning of the 2^nd parison. These component(s) may comprise, without limitation, at least one selected from the group of a bracket, a connector, a cooling channel, a sensor, a valve, and a vent.

[0007] The method may also comprise joining the at least two parts (Part 1 & Part 2) together after the part(s) are removed from the mold. This joining technique may be accomplished through the use of one or more of mechanical fastening, adhesive bonding, force- or form-fitting, ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding, and/or an overmolding process.

[0008] According to one aspect of the present disclosure, the 1^st parison comprises a 1^st material composition and the 2^nd parison comprises a 2^nd material composition; wherein the 1^st material composition and the 2^nd material composition are either different or substantially the same. The 1^st material composition and the 2^nd material composition may be independently selected as an elastomer, a thermoplastic, a thermoplastic elastomer (TPE), or a copolymer, blend, or mixture thereof. Alternatively, at least one of the 1^st material composition and the 2^nd material composition may have a Shore A hardness that is in the range of about 40 to 100 or a Shore D hardness that is in the range of 20 to about 75. The composition of the 1 ^st parison and the 2^nd parison may be selected based on a combination of properties, including but not limited to hardness, cost, environmental impact, and the processing method available to form the reinforced hollow structure. One skilled in the art will understand that in addition to the 1^st parison and 2^nd parison, at least one other parison or the use of multi-layer co-extrusion blow molding or like technology may be incorporated into the processing method in order to provide for a multilayer structure comprising different material layers as required or desired in order to adjust the mechanical and/or barrier properties associated with the formed structure.

[0009] Alternatively, the 1^st material composition and/or the 2^nd material composition is a thermoplastic elastomer (TPE) that has a Shore A hardness in the range of about 50 to about 90 or a Shore D hardness of about 45 to about 75; alternatively, the Shore A hardness is in the range from about 70 to about 80. The Shore A hardness and/or the Shore D hardness may be measured using a Shore® (Durometer) test according to ASTM

D22440 00, ISO 7619 and ISO 868; DIN 53505; and/or JIS K 6301 , which has been superseded by JIS K 6253. The TPE used may comprise, without limitation styrenic block copolymers (TPE-S), polyolefin blends (TPE-O), thermoplastic polyurethanes (TPE-ll), thermoplastic copolyesters (TPE-E), thermoplastic polyamides (TPE-A), or a mixture thereof.

[0010] Alternatively, the 1^st material composition and/or the 2^nd material composition is a thermoplastic that has a Shore D hardness in the range of about 60 to 75. When desirable, at least one of the 1^st material composition and the 2^nd material composition may comprise high density polyethylene (HDPE). polypropylene (PP), polyamide (PA), or a combination thereof either as copolymers, a polymeric blend/mixture, or as a multilayered structure or composite.

[0011] According to another aspect of the present disclosure, at least one of the 1^st material composition and the 2^nd material composition comprises a thermally conductive polymeric material. This thermally conductive polymeric material may include a polymer having intrinsic thermal conductivity; a blend of polymers, wherein one or more of the polymers in the blend has intrinsic thermal conductivity; a composite polymeric material having at least one polymer configured as a polymeric matrix with a thermally conductive filler dispersed therein; or a combination thereof.

[0012] The thermally conductive filler may comprise a plurality of particles having a composition that includes, without limitation, boron nitride, alumina, aluminum nitride, silicon nitride, silicon carbide, graphene, carbon nanotubes, or a mixture thereof. One specific example of a thermally conductive polymeric material includes having at least one of the 1^st material composition and the 2^nd material composition comprise a composite polymeric material wherein a plurality of boron nitride particles are dispersed in a thermoplastic elastomer (TPE) matrix exhibiting a Shore A hardness in the range of about 70 to about 80.

[0013] The fiber layer may comprise glass fibers, carbon fibers, polyamide fibers, or a combination thereof. These fibers may constitute long fibers or be woven into a bidirectional fabric.

[0014] The reinforced hollow structure may be formed with an overall wall thickness (w) that is in the range of about 0.2 millimeters to about 5.0 millimeters; alternatively, about 0.3 millimeters (mm) to about 2.5 mm. Alternatively, the wall thickness (w) may in the range of about 0.5 mm to about 2.3 mm; alternatively, about 1 .0 mm to about 2.0 mm. The wall thickness (w) of the various sections of the reinforced hollow structure, e.g., the top section, the bottom section, and the sides(s) that join the top section and bottom section, may be the same or different depending upon the structural design and manufacturing parameters utilized for the given application. For example, the selection of the wall thickness (w) may vary depending upon the thickness necessary to provide for adequate stiffness as required by any predetermined application and/or to maintain a stress level in the reinforced hollow structure that is below the yield stress of the plastic material composition(s) that are used to form the structure.

[0015] The reinforced hollow structure may further comprise one or more cavities are formed therein, such that at least one cavity is configured to at least partially be filled with a fluid for the purpose of heat transfer. [0016] According to yet another aspect of the present disclosure a method of forming a battery pack with thermal management is provided. This method generally comprises providing a reinforced hollow structure as previously described above and as further defined herein, wherein the reinforced hollow structure is in at least two parts (Part 1 & Part 2); providing at least one battery; and joining the at least two parts (Part 1 & Part 2), such that the at least one battery is held within the confines of the joined reinforced hollow structure. When utilized for the thermal management of a battery or battery pack, the method may further comprise filling the reinforced hollow structure with a fluid. In a similar fashion, the method may further comprise forming a fluid inlet and a fluid outlet in the reinforced hollow structure, such that the fluid is allowed to flow into and out of the reinforced hollow structure in order to provide for the thermal management of the battery pack.

[0017] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings. The components in each of the drawings may not necessarily be drawn to scale, but rather emphasis is placed upon illustrating the principles of the invention. [0019] Fig. 1 is a schematic representation that describes a blow molding process used to form a reinforced hollow structure according to the teachings of the present disclosure.

[0020] Fig. 2 is a schematic representation of a cross-section of the wall in the reinforced hollow structure in Fig. 1 (Part 1 ) formed according to the teachings of the present disclosure.

[0021] Fig. 3 is a schematic representation that describes a process of forming a battery a battery pack with thermal management using the reinforced hollow structure of Fig. 1.

[0022] The drawings are provided herewith for purely illustrative purposes and are not intended to limit the scope of the present invention.

DETAILED DESCRIPTION

[0023] The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. For example, the reinforced hollow structure made according to the teachings contained herein is described throughout the present disclosure as a high voltage battery enclosure (HVBE) used for the thermal management of a battery or battery pack in an electric vehicle (EV) or a hybrid electric vehicle (HEV) in order to more fully illustrate the structural elements and the use thereof. The incorporation and use of such a reinforced hollow structure in other applications, including without limitation, in other electric equipment or devices that utilize a battery or battery pack is contemplated to be within the scope of the present disclosure. In addition, other power electronics devices, such as metal oxide semiconductor field effect transistors (MOSFETs), gate turn-off thyristors (GTOs), insulated-gate bipolar transistors (IGBTs), and integrated gate-commutated thyristors (IGCTs), which are widely accepted for efficient delivery of electrical power in home electronics, industrial drives, telecommunication, transport, electric grid, and numerous other applications, may greatly benefit from the reinforced hollow structure concept set forth herein. It should be understood that throughout the description and drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0024] In addition, the process as described herein uses a 1 ^st and a 2^nd parison to form the walls of the reinforced hollow structure in order to more fully illustrate the structural elements and the use thereof. However, when required or desirable to adjust the mechanical and/or barrier properties of the structure, the use of one or more additional parisons comprising different material(s) or the use of multi-layer co-extrusion blow molding or like technology is possible in order to form a multi-layered structure.

[0025] As used herein a “battery cell” refers to the basic electrochemical unit of a battery that contains an anode and a cathode, as well as any components used to convert stored chemical energy to electricity, such as, for example, electrodes, a separator, and an electrolyte. In comparison, a “battery” or “battery module” refers to at least one battery cell placed within a housing with electrical connections and possibly electronics for control and protection. A “battery pack” refers to a collection of more than one battery, in other words a plurality of battery modules, connected either in series or parallel to one another in order to increase the voltage or capacity arising therefrom with the collection of batteries being secured within a housing.

[0026] Within this specification, embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without departing from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein.

[0027] The present disclosure provides a method of forming a reinforced hollow structure, such as an enclosure for a battery or battery pack, which generally includes utilizing a blow molding process to incorporate a long glass, or fiber reinforcement between two layers of a polymeric parison. The formation of a blow molded enclosure creates a single form structure that greatly reduces the number of leak paths seen in conventional metal enclosures. A blow molded enclosure may also exhibit less weight as compared to metal counterparts, while providing similar structural strength. By inserting a reinforcement layer during the blow molding process instead of having it incorporated in the plastic resin prior to the process allows for continual use of conventional blow molding polymers and currently known manufacturing process steps.

[0028] The use of dual molding technology, in which a glass or another fiber reinforcement is placed between two parisons in a blow molding process, produces a reinforced hollow structure or enclosure that exhibits sufficient structural strength to meet all necessary regulatory requirements. This reinforcement may also be placed in targeted locations that require greater strength, while reducing the amount of reinforcement material placed in less critical areas. In addition to increasing the strength of a conventional blow molding material, a manufacturing process that adds such a fiber reinforcement also reduces the overall manufacturing cost. The use of a glass or other fiber reinforcement as a separate layer, allows for targeted use of the reinforcement in critical areas while allowing non-critical areas to be formed of only the base plastic material, thereby reducing the amount (e.g., cost) of the reinforcement material that is required.

[0029] For the purpose of this disclosure, the terms "about" and "substantially" as used herein with respect to measurable values and ranges refer to the expected variations known to those skilled in the art (e.g., limitations and variability in measurements).

[0030] For the purpose of this disclosure, the terms "at least one" and "one or more of” an element are used interchangeably and may have the same meaning. These terms, which refer to the inclusion of a single element or a plurality of the elements, may also be represented by the suffix "(s)" at the end of the element. For example, "at least one fiber", "one or more fibers", and "fiber(s)" may be used interchangeably and are intended to have the same meaning.

[0031] Referring now to Fig. 1 a method 100 of forming a reinforced hollow structure 25 is provided. This method generally comprises providing 105 an initially open blow mold 1 and positioning a 1^st parison 5 therein. The open blow mold 1 generally includes at least two halves 3A, 3B. The blow mold 1 is then closed 110 and a pressurized fluid 7 is provided that causes the 1^st parison 5 to expand. The 1^st parison 5 is allowed 115 to form the shape of an outer wall 5w that defines the periphery of the reinforced hollow structure 25. The mold 1 is then opened 120, thereby, separating the outer wall 5w into at least two sections. A fiber layer 10 is inserted 125 into the open mold 1 . A 2^nd parison 15 is positioned 130 in the open mold 1 . The mold 1 is closed 135 and a pressurized fluid 17 is provided that causes the 2^nd parison 15 to expand. The 2^nd parison 15 is allowed 140 to form the shape of an inner wall 15w that secures the fiber layer 10 between the inner wall 15w and the outer wall 5w, thereby, forming the reinforced hollow structure 25. The mold 1 is then opened 145 to remove the reinforced hollow structure 25 with the structure 25 being separated into at least two parts (Part 1 & Part 2).

[0032] When required by an application in which the reinforced hollow structure 25 will be utilized or when desirable, the method 100 may further comprise inserting 103, 127 one or more components 20 into the mold 1 prior to the positioning 110 of the 1 ^st parison 5 and/or prior to positioning 130 of the 2^nd parison 15. The one or more components 20 may include, without limitation, brackets, connectors, cooling channels, sensors, valves, and vents. Alternatively, at least one of the components 20 is a bracket, a connector, a cooling channel, a sensor, a valve, or a vent. The various components 20 that are inserted into the mold 1 become secured in place within the reinforced hollow structure 25 via the expansion 110, 135 of either the 1 ^st or 2^nd parison(s) 5, 15.

[0033] The mold generally comprises at least two parts; alternatively, the mold includes two parts (Part 1 & Part 2). The mold may be made using any conventional material known in the art, including, without limitation, aluminum, zinc, steel, or a ceramic composite. Alternatively, aluminum is used in forming the mold due to its high rate of heat transfer, which reduces the need for costly conformal mold cooling. The two parts (Part 1 & Part 2) represent mold halves that have an inner surface, which defines at least one cavity within the mold when the mold is closed.

[0034] Upon closing the mold halves (Part 1 & Part 2) a blow pin may be provided within the parison in the closed mold in order to provide a pressurized fluid into the parison so that the parison expands within the mold. This pressurized fluid may comprise, but not be limited to, a pressurized inert gas, reactive gas, or combination thereof. When desirable, the pressurized fluid may be a liquid without exceeding the scope of the present disclosure. Several specific examples of inert gases include, without limitation, air, nitrogen, argon, carbon dioxide, and the like. A specific example of a reactive gas includes, without limitation, fluorine. Alternatively, the pressurized fluid is air.

[0035] The pressurized fluid may be provided at a pressure that ranges from about 1 bar (~14.5 psi) to 15 bar (217.5 psi); alternatively, about 1.75 bar (~25 psi) to about 10.4 bar (~150 psi); alternatively, about 4 (~58 psi) to about 8 bar (~116 psi). This pressure may be held for a predetermined amount of time that allows the expanded parison to form the shape of the internal contour of the cavity within the blow mold. This predetermined amount of time may range from about 5 seconds to 1 minute; alternatively, about 15 seconds to about 45 seconds; alternatively, about 15 seconds to about 25 seconds; alternatively, about 30 seconds to about 40 seconds.

[0036] As used herein, the term “parison” may include a soft, hot, moldable or formable material having at least one layer of a plastic composition. The parison may be extruded from an extrusion or co-extrusion machine. In this context, the term "extruding” includes extrusion of a mono-layer parison or co-extrusion of a multi-layer parison. Any type of blow molding known in the art may be utilized, including but not limited to extrusion blow molding (EBM), injection blow molding (IBS), or injection stretch blow molding (ISBM).

[0037] The main difference(s) between the various blow molding techniques or types are related to how the parison is formed, the size of the parison that is formed, and how the parison is moved between molds or within a mold. Each of the blow molding processes in general include devices, such as extruders, molding and drawing machines, grippers, spreaders, and blow pins, whose structure and function are well known to those skilled in the art and, therefore, need no further discussion herein. [0038] The parison is generally heated to a temperature that is near, but below the melting temperature of the material composition of the plastic in the parison. This heating is accomplished either before or upon insertion of the parison into the blow mold. The temperature to which the parison is heated may be between 125°C and 250°C; alternatively, the temperature is in the range of about 140°C and 225°C; alternatively, in the range of about 150°C and 200°C.

[0039] The 1^st parison comprises a 1^st material composition and the 2^nd parison comprises a 2^nd material composition, such that the 1^st material composition and the 2^nd material composition are either different or substantially the same. The 1st material composition and the 2nd material composition may be independently selected as one from the group of an elastomer, a thermoplastic, a thermoplastic elastomer (TPE), and a copolymer, blend, or mixture thereof. Alternatively, at least one of the 1^st material composition and the 2^nd material composition has a Shore A hardness that is in the range of about 40 to 100 or a Shore D hardness that is in the range of 20 to about 75.

[0040] Alternatively, the 1^st and 2^nd material compositions may comprise, but not be limited to, acrylonitrile butadiene styrene (ABS), high-density polyethylene (HDPE), low- density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyurethane (Pll), santoprene, kostrate, acrylic, polyoxymethylene (e.g., Delrin®), polypheylene sulfide (PPS), polyetheretherketone (PEEK), polyvinylchloride (PVC), polycarbonate (PC), polyester, polyetherimide (e.g., llltem®), polybutylene terephthalate (PBT), and mixtures or copolymers thereof. Alternatively, at least one of the 1^st material composition and the 2^nd material composition comprises high density polyethylene (HDPE). polypropylene (PP), polyamide (PA), or a combination thereof either as copolymers, a polymeric blend/mixture, or as a multi-layered structure or composite.

[0041] Alternatively, at least one of the 1^st material composition and the 2^nd material composition is a thermally conductive polymeric material. This thermally conductive polymeric material may comprise a polymer having intrinsic thermal conductivity; a blend of polymers, wherein one or more of the polymers in the blend has intrinsic thermal conductivity; a composite polymeric material having at least one polymer configured as a polymeric matrix with a thermally conductive filler dispersed therein; or a combination thereof.

[0042] The thermally conductive filler may comprise a plurality of particles having a composition that comprises, without limitation, or consists of boron nitride, alumina, aluminum nitride, silicon nitride, silicon carbide, graphene, carbon nanotubes, or a mixture thereof. The particles may have any feasible shape including without limitation, spherical, flat (e.g., platelets), irregular, or oblong (e.g., fibers). The particles may also be described as being in any feasible crystalline form that provides for thermal conductivity. Alternatively, boron nitride when used as the conductive filler provides a level of thermal conductivity and electric insulation desirable for use in many applications. Boron nitride (BN) particles when used as the thermally conductive filler may comprise either a hexagonal crystallographic form (H-BN) or a cubic crystallographic form (C-BN); alternatively, the thermally conductive filler is H-BN.

[0043] One specific example of a reinforced hollow structure includes a composition in which at least one of the 1^st material composition and the 2^nd material comprises a composite polymeric material having a plurality of boron nitride particles dispersed in a thermoplastic elastomer (TPE) matrix that has a Shore A hardness in the range of about 70 to about 80. The thermally conductive filler may comprise between about 5 wt.% to about 30 wt.% of the overall weight of the composite polymeric material. Alternatively, the thermally conductive filler 75 comprises between about 5 wt.% to about 25 wt.%; alternatively, between about 10 wt.% to about 20 wt.% of the overall weight of the composite polymeric material.

[0044] Referring now to both Fig. 1 and Fig. 2, the reinforced hollow structure 25 as removed from the mold 1 comprises at least two parts (Part 1 & Part 2). Each of the parts (Part 1 & Part 2) generally comprise a layered wall structure 30, wherein the fiber layer 10 is located between the outer wall 5w and the inner wall 5w formed by the 1 ^st parison 5 and the 2^nd parison 15, respectively. Fig. 2 provides a magnified depiction of a region labeled as x in the layered wall structure 30 of Part 1 of the reinforced hollow structure 25 as removed 145 from the mold 1 in Fig. 1.

[0045] For the purpose of this disclosure, the term “integrally formed” or “formed integrally” is meant to imply that two or more structural element(s) and/or component(s) are formed or molded as a single component and/or that these structural element(s) and/or component(s) are formed separately and then joined together to form a permanent bond there between. For example, the two separate parts (Part 1 & Part 2) of the reinforced hollow structure 25 removed 145 from the mold 1 in Fig. 1 may be joined together to form a permanent bond there between, thereby, providing a “leak-free” reinforced hollow structure 25. The separate structural element(s) (e.g., Part 1 & Part 2) and/or component(s) may be joined through the use of one more of mechanical fastening, adhesive bonding, force- or form-fitting, ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding, and/or an over-molding process. Several examples of mechanical fastening include, without limitation, the use of screws, bolts, nuts, latches, clips, snaps, or the like. Force-fitting refers to the joining of parts in which one part is forced or pressed into another part in order to form a joined or single unit. Form-fitting refers to the surface of one part conforming closely to the shape, form, or outline of the surface of another part (e.g., a latching mechanism, etc.). Alternatively, the separate structural element(s) (e.g., Part 1 & Part 2) are integrally formed by being joined together. Alternatively, the structural elements are joined by a form of welding.

[0046] The fiber layer 10 may comprise, consist of, or consist essentially of glass fibers, carbon fibers, polyamide fibers, or a combination thereof. The fiber layer 10 may include, without limitation, a plurality of continuous or long (unidirectional) fibers, and/or a woven (bidirectional) fabric. Alternatively, the fiber layer 10 is a plurality of continuous or long (unidirectional) fibers. The soft, e.g., somewhat molten material compositions (1^st & 2^nd) that form the outer and inner walls of the hollow reinforced structure become either melt bonded or welded to each other, thereby securing the fiber layer by at least partially encompassing or encasing the fiber layer there between.

[0047] The reinforced hollow structure comprises a wall thickness that is in the range of about 0.2 millimeters (mm) to about 5 mm; alternatively, the wall thickness is in the range of about 0.3 mm to about 2.5 mm; alternatively, greater than 0.5 mm; alternatively, less than 4.0 mm. The wall thickness is defined to include the thickness of the inner wall formed by the 2^nd parison, the fiber layer, and the outer wall formed by the 1 ^st parison. Referring once again to Fig. 2, the wall thickness is shown by the reference number w. [0048] The reinforced hollow structure may include one cavity or multiple cavities therein. Alternatively, the reinforced hollow structure comprises one or more cavities. When the application for which the reinforced hollow structure is utilized requires thermal management, at least one of the cavities in the reinforced hollow structure may be configured to at least partially be filled with a fluid capable of providing for heat transfer. This fluid may be, without limitation, water, a water/glycol mixture, or a heat transfer fluid, such as a silicone oil or the like.

[0049] According to another aspect of the present disclosure, a method of forming a battery pack with thermal management is provided. Referring now to Fig. 3, this method 200 generally comprises providing 205 a reinforced hollow structure that is in at least two parts (e.g., Part 1 & Part 2) as previously described above and further defined herein; providing 210 at least one battery; and joining 215 the at least two parts (Part 1 & Part 2) together, such that the at least one battery is held within the confines of the joined reinforced hollow structure. When the enclosure is utilized to provide thermal control, the joined reinforced hollow structure may be filled 220 with a fluid, wherein a fluid inlet and fluid outlet formed 225 in the reinforced hollow structure allows the fluid to flow into and out of the structure in order to provide for the desired thermal management of the battery pack. The joining of the at least two parts (Part 1 & Part 2) may be accomplished as previously discussed herein using a process that creates a permanent seal providing for a “leak-free” enclosure.

[0050] The use of a polymeric material to form the reinforced hollow structure provides sufficient ability for inner wall of the reinforced hollow structure to conform to and establish contact with the batteries, overcoming any surface roughness or unevenness that may inherently exist. The inner wall of the reinforced hollow structure is able to maintain at least 50% surface contact with the batteries. Alternatively, the inner wall of the reinforced hollow structure is capable of maintaining between 50% and 100% surface contact with the batteries; alternatively, greater than 50% and less than 100%; alternatively, between 55% and 95%; alternatively, about 60% to about 90%. For the purpose of the present disclosure, the term “between” is intended to include the limits specified for the stated range.

[0051] One skilled in the art will understand that the process steps in the method as described above and in Figure 6, as well as those further defined herein are not limited to being performed in the sequential order listed, but rather the process steps may be performed in any desired or required order based upon the selection of the materials and the manufacturing equipment and techniques chosen for processing the materials. Each of the process steps may be conducted consecutively or simultaneously, such as a step being combined with and run in conjunction with or as part of another of the process steps. Alternatively, when desirable, the process steps may be conducted in the sequential order provided.

[0052] Those skilled-in-the-art, in light of the present disclosure, will appreciate that many changes can be made in the specific embodiments which are disclosed herein and still obtain alike or similar result without departing from or exceeding the spirit or scope of the disclosure. One skilled in the art will further understand that any properties reported herein represent properties that are routinely measured and can be obtained by multiple different methods. The methods described herein represent one such method and other methods may be utilized without exceeding the scope of the present disclosure. [0053] The foregoing description of various forms of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Numerous modifications or variations are possible in light of the above teachings. The forms discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various forms and with various modifications as are suited to the particular use contemplated. Thus, the invention is not limited in its execution to the abovementioned preferred exemplary embodiments. Rather, a number of variants are conceivable that make use of the illustrated solution even in the form of fundamentally different embodiments. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

1 . A method of forming a reinforced hollow structure, the method comprising: providing an initially open blow mold and positioning a 1^st parison therein; closing the mold and providing a pressurized fluid that causes the 1^st parison to expand; allowing the 1 ^st parison to form the shape of an outer wall that defines the periphery of the reinforced hollow structure; opening the mold and separating the outer wall into at least two sections; inserting a fiber layer into the mold; positioning a 2^nd parison in the mold; closing the mold and providing a pressurized fluid that causes the 2^nd parison to expand; allowing the 2^nd parison to form the shape of an inner wall that secures the fiber layer between the inner wall and the outer wall, thereby forming the reinforced hollow structure; and opening the mold to remove the reinforced hollow structure and separating said reinforced hollow structure into at least two parts (Part 1 & Part 2).

2. The method according to claim 1 , wherein the method further comprises inserting one or more components into the mold prior to the positioning of the 1^st parison and/or prior to positioning of the second parison.

3. The method according to claim 2, wherein the one or more components comprise at least one selected from the group of a bracket, a connector, a cooling channel, a sensor, a valve, and a vent.

4. The method according to any of claims 1 to 3, wherein the 1^st parison comprises a 1^st material composition and the 2^nd parison comprises a 2^nd material composition; wherein the 1^st material composition and the 2^nd material composition are either different or substantially the same.

5. The method according to claim 4, wherein the 1^st material composition and the 2^nd material composition are independently selected as one from the group of an elastomer, a thermoplastic, a thermoplastic elastomer (TPE), and a copolymer, blend, or mixture thereof.

6. The method according to any of Claims 4 to 5, wherein at least one of the 1^st material composition and the 2^nd material composition has a Shore A hardness that is in the range of about 40 to 100 or a Shore D hardness that is in the range of 20 to about 75.

7. The method according to any of Claims 4 to 6, wherein at least one of the 1^st material composition and the 2^nd material composition is a thermally conductive polymeric material.

8. The method according to Claim 7, wherein the thermally conductive polymeric material comprises a polymer having intrinsic thermal conductivity; a blend of polymers, wherein one or more of the polymers in the blend has intrinsic thermal conductivity; a composite polymeric material having at least one polymer configured as a polymeric matrix with a thermally conductive filler dispersed therein; or a combination thereof.

9. The method according to Claim 8, wherein the thermally conductive filler comprises a plurality of particles having a composition selected from the group consisting of boron nitride, alumina, aluminum nitride, silicon nitride, silicon carbide, graphene, carbon nanotubes, or a mixture thereof.

10. The method according to any of Claims 4 to 9, wherein at least one of the 1^st material composition and the 2^nd material composition comprises a composite polymeric material having a plurality of boron nitride particles dispersed in a thermoplastic elastomer (TPE) matrix having a Shore A hardness in the range of about 70 to about 80.

11. The method according to any of Claims 4 to 10, wherein at least one of the 1^st material composition and the 2^nd material composition comprises high density polyethylene (HDPE). polypropylene (PP), polyamide (PA), or a combination thereof either as copolymers, a polymeric blend/mixture, or as a multi-layered structure or composite.

12. The method according to any of claims 1 to 11 , wherein the fiber layer comprises glass fibers, carbon fibers, polyamide fibers, or a combination thereof.

13. The method according to any of claim 1 to 12, wherein the reinforced hollow structure comprises a wall thickness that is in the range of about 0.3 millimeters (mm) to about 2.5 mm.

14. The method according to any of Claims 1 to 13, wherein one or more cavities are formed within the reinforced hollow structure, such that at least one cavity being configured to at least partially be filled with a fluid for the purpose of heat transfer.

15. The method according to any of Claims 1 to 14, wherein the method further comprises joining the at least two parts (Part 1 & Part 2) together.

16. The method according to Claim 15, wherein the joining of the at least two parts (Part 1 & Part 2) is accomplished through the use of one or more of mechanical fastening, adhesive bonding, force- or form-fitting, ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding, and/or an overmolding process.

17. A method of forming a battery pack with thermal management, wherein the method comprises: providing a reinforced hollow structure according to any of Claims 1 to 14, wherein the reinforced hollow structure is in at least two parts (Part 1 & Part 2); providing at least one battery; and joining the at least two parts (Part 1 & Part 2), such that the at least one battery is held within the confines of the joined reinforced hollow structure.

18. The method according to Claim 17, wherein the joining of the at least two parts (Part 1 & Part 2) is accomplished through the use of one or more of mechanical fastening, adhesive bonding, force- or form-fitting, ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding, and/or over-molding process.

19. The method according to any of Claims 17 or 18, wherein the method further comprises filling the reinforced hollow structure with a fluid.

20. The method according to claim 19, wherein the method further comprises forming a fluid inlet and a fluid outlet in the reinforced hollow structure, such that the fluid is allowed to flow into and out of the reinforced hollow structure in order to provide for the thermal management of the battery pack.