Double-walled battery housing for providing heat transfer

Abstract

A double-walled enclosure for thermal management of a battery pack, the double-walled enclosure comprising an inner hollow structure and an outer hollow structure, the inner hollow structure having an inner surface and an outer surface; one or more battery modules are positioned in the inner hollow structure; the outer hollow structure has an inner surface wherein the outer surface of the inner hollow structure is either in contact with or forms at least one channel with the inner surface of the outer hollow structure through which the heat transfer fluid flows. The inner hollow structure is formed from a polymeric material such that the inner hollow structure is in thermal contact with the heat transfer fluid to provide thermal management of the battery pack.

Description

Technical Field

[0001] The present invention relates to a battery housing for providing thermal management for a battery or a battery module and / or a battery pack. Background Art

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

[0003] Currently, in electric vehicles (EV) or hybrid electric vehicles (HEV), aluminum plates are commonly used to provide heat transfer for battery packs. The cooling plate is typically located at the bottom of the battery pack, which typically houses multiple batteries or battery modules. The cooling plate allows a fluid to circulate therein for heat transfer. Examples of commonly used fluid types include water or water / ethylene glycol mixtures. Since the aluminum plate is conductive, some form of polymer pad or adhesive layer is typically provided between the batteries in the battery pack and the cooling plate. Therefore, the pad is in physical contact with both the battery and the cooling plate. The use of the pad also helps to eliminate any air gaps that exist due to assembly tolerances and the roughness of the outer surface of the battery and the outer surface of the cooling plate. The pad or adhesive layer combined with the aluminum plate may have a negative impact on the cost, assembly, recycling and weight of the battery pack / cooling plate combination.

[0004] Another type of cooling plate can be formed using a film or composite foil as a flexible top layer combined with a rigid lower plate. The film or composite foil has a very thin cross-section with a cross-sectional thickness of about 100 μm (micrometer) or less. As the fluid circulates in the composite foil, the composite foil expands, similar to a balloon. All contact forces applied to the battery are achieved via this expansion technology. However, because the thin cross-section of the expandable membrane is limited in thermal conductivity and is susceptible to tearing, the performance and life of this type of cooling plate remain to be determined. In addition, the film or composite foil may not be able to withstand the weight or dynamic forces applied by the battery that the film or foil is trying to support.

[0005] Finally, a third method of removing heat from the battery has been used to a limited extent in some hybrid vehicles such as the McLaren Speedtail. This method involves surrounding the battery with a dielectric fluid. In this type of thermal management process, the dielectric fluid needs to be circulated or forced to flow to an external heat exchanger to remove the heat generated by the battery. Furthermore, the dielectric fluid used in this method is dependent on the availability of large quantities of such dielectric fluids and the costs associated with them. Summary of the invention

[0006] The object of the present disclosure is to overcome the above-mentioned shortcomings and provide an improved battery housing for thermal management of batteries or thermal management of battery packs. In this regard, the present disclosure generally includes a double-walled housing for thermal management of batteries. The double-walled housing includes: an inner hollow structure and an outer hollow structure, the inner hollow structure having an inner surface and an outer surface; one or more battery modules are positioned in the inner hollow structure; the outer hollow structure has an inner surface, wherein the outer surface of the inner hollow structure is either in contact with the inner surface of the outer hollow structure, or forms at least one channel with the inner surface of the outer hollow structure, and a heat transfer fluid flows through the at least one channel. The inner hollow structure includes a polymer material so that the inner hollow structure is in thermal contact with the heat transfer fluid to provide thermal management of the battery pack. When desired, the polymer material may include a thermally conductive polymer material.

[0007] The wall thickness of the inner hollow structure of the double-walled shell is in the range of about 0.3 mm (millimeter) to about 2.5 mm. Similarly, the wall thickness of the outer hollow structure is in the range of about 1 mm to about 5 mm.

[0008] A cavity may be formed between one or more battery modules and the inner surface of the inner hollow structure. In this case, the cavity is at least partially filled with a heat transfer medium. The heat transfer medium may include, but is not limited to, a single-phase dielectric fluid, a multi-phase dielectric fluid, a phase change material, or a combination of the above materials.

[0009] At least one channel formed between the inner hollow structure and the outer hollow structure can be located above, below, at least one side, or a combination of the above relative to one or more battery modules. The heat transfer fluid flowing in the at least one channel can include, but is not limited to, water, ethylene glycol, or a water / ethylene glycol mixture. The heat transfer fluid can be circulated to a radiator, a cooler, a heat exchanger, or the like.

[0010] The polymer material forming the inner hollow structure may include an elastomer, a thermoplastic material, a thermoplastic elastomer (TPE), or a combination of the above materials. When desired, the Shore A hardness of the polymer material may be in the range of about 40 to 100, or its Shore D hardness may be in the range of 20 to about 75. Typically, when it is desired to enhance thermal conductivity, the polymer material may be a thermally conductive polymer material. Typically, the thermally conductive polymer material may include a polymer with inherent thermal conductivity, a blend of polymers, a composite polymer material, or a combination of the above materials, wherein one or more polymers in the blend have inherent thermal conductivity, and the composite polymer material has at least one polymer configured as a polymer matrix, and a thermally conductive filler is dispersed in the polymer matrix.

[0011] When the component of the thermally conductive polymer material comprises a composite polymer material having a polymer matrix in which a thermally conductive filler is dispersed, the thermally conductive filler may comprise a plurality of particles, the component of the plurality of particles being selected from the group consisting of boron nitride, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, graphene, carbon nanotubes, or a mixture thereof. The polymer matrix may be an elastomer, a thermoplastic material, or a thermoplastic elastomer (TPE) having a Shore A hardness in the range of about 40 to 100, or a Shore D hardness in the range of about 20 to about 75. Alternatively, the component of the composite polymer material comprises a plurality of boron nitride particles dispersed in a thermoplastic elastomer (TPE) having a Shore A hardness in the range of about 70 to about 80. The thermally conductive filler comprises between about 5 wt.% and about 25 wt.% of the total weight of the composite polymer material.

[0012] The components of the outer hollow structure may include any standard or known polymer components that can provide structural support for the battery pack. The polymer components may include, but are not limited to, high-density polyethylene (HDPE), polypropylene (PP), polyamide (PA), or combinations of the above materials, which are copolymers, polymer blends / mixtures, or multilayer structures or composite materials.

[0013] According to one aspect of the present disclosure, the inner hollow structure may include one or more structural elements, one or more structural elements configured to support the weight of the battery or to serve as a buffer stop configured to assist in placing and retaining the battery. The components of the one or more structural elements may be the same or different from the components of the inner hollow structure. In addition, the one or more structural elements may be integrally formed with the inner hollow structure or formed as an insert attached to the inner hollow structure.

[0014] According to another aspect of the present disclosure, when desired, at least one of the outer surface of the inner hollow structure or the inner surface of the outer hollow structure may include one or more features configured to increase stiffness and promote fluid mixing by directing fluid flow. These features may protrude into at least one channel. However, at least a portion of the outer surface of the inner hollow structure is flat, and the at least a portion forms a portion of at least one channel so as to maintain at least 50% surface contact with the heat transfer fluid in at least one channel. When allowing the heat transfer fluid to flow through at least one channel, the volume change produced by the inner hollow structure and the outer hollow structure is less than about 15%.

[0015] According to another aspect of the present disclosure, a battery pack with thermal management is provided. The battery pack includes at least one battery module and a double-walled housing including an inner hollow structure and an outer hollow structure as previously described above and as otherwise defined herein.

[0016] According to another aspect of the present disclosure, a double wall enclosure may be used to provide thermal management for at least one battery in an electric vehicle (EV) or a hybrid electric vehicle (HEV).

[0017] According to another aspect of the present disclosure, a process for forming a battery pack configured for thermal management is provided. The process includes: providing a polymer material; molding an inner hollow structure with the polymer material, the inner hollow structure having an outer surface and an inner surface; molding an outer hollow structure, the outer hollow structure having an inner surface, the inner surface surrounding the outer surface of the inner hollow structure, wherein the outer surface of the inner hollow structure is either in contact with the inner surface of the outer hollow structure or forms at least one channel with the inner surface of the outer hollow structure; providing at least one battery; assembling at least one battery in the inner hollow structure, wherein one or more cavities are formed between the battery and the inner surface of the inner hollow structure; filling one or more cavities with a heat transfer medium; and allowing the heat transfer fluid to flow through at least one channel, the at least one channel being located between the inner surface of the outer hollow structure and the outer surface of the inner hollow structure. The molding process used in the process can be selected from one of the groups including: blow molding, injection molding, compression molding, rotational molding, or a combination of the above processes.

[0018] When desired, the process may also include forming one or more structural elements present in the inner hollow structure to assist in supporting the weight of the battery or battery module or to serve as a buffer stop for placing and retaining such a battery. These structural elements may be formed by a molding process such as, for example, blow molding using "ship in a bottle (SIB)" technology or "tank advanced process technology (TAPT)".

[0019] When desired, the process may also include forming one or more features that protrude from the inner surface of the outer hollow structure into at least one channel, or from the outer surface of the inner hollow structure into at least one channel, to increase stiffness and / or promote fluid mixing by directing fluid flow.

[0020] 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

[0021] In order to better understand the present disclosure, many forms of the present disclosure will now be described by way of example with reference to the accompanying drawings. The components in each figure are not necessarily drawn to scale, emphasis instead being placed upon illustrating the principles of the present invention.

[0022] Figure 1Ais a schematic illustration showing a peripheral cross-sectional view of a battery pack containing batteries within a double-walled enclosure formed in accordance with the teachings of the present disclosure.

[0023] Figure 1B yes Figure 1A A cross-sectional view of a battery pack and a housing taken along the axis x.

[0024] Figure 2A is a cross-sectional view of another battery pack formed according to the teachings of the present disclosure.

[0025] Figure 2B is a cross-sectional view of yet another battery pack formed according to the teachings of the present disclosure.

[0026] Figure 3 is with Figure 1B A cross-sectional view of another battery pack and housing similar to the battery pack and housing shown, wherein one or more structural supports are provided in the structure of the double wall housing.

[0027] Figure 4A is a schematic illustration showing a peripheral cross-sectional view of a battery pack containing batteries within another double-walled enclosure formed in accordance with the teachings of the present disclosure.

[0028] Figure 4B yes Figure 4A A cross-sectional view of a battery pack and a housing taken along the axis x.

[0029] Figure 5 is a partial perspective view of a section of a housing highlighting features for fluid flow through one or more channels protruding into the housing.

[0030] Figure 6 is a process flow diagram for forming a battery pack including batteries within a double-walled enclosure in accordance with the teachings of the present disclosure.

[0031] The drawings provided herein are for illustration purposes only and are not intended to limit the scope of the present invention. DETAILED DESCRIPTION

[0032] The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or use in any way. For example, throughout the present disclosure, a battery housing manufactured and used according to the teachings contained herein is described in conjunction with thermal management of a battery or battery pack in an electric vehicle (EV) or hybrid electric vehicle (HEV) to more fully illustrate the structural elements and their use. In other applications, including but not limited to other electrical devices or apparatuses using batteries or battery packs, the combination and use of such a battery housing is considered to be within the scope of the present disclosure. In addition, other power electronic 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) widely used in efficient power delivery in home electronics, industrial drives, telecommunications, transportation, power grids, and many other applications can benefit significantly from the double-walled housing described herein. It should be understood that throughout the specification and the accompanying drawings, corresponding reference numerals represent similar or corresponding components and features.

[0033] As used herein, a "battery cell" refers to the basic electrochemical unit of a battery, which includes an anode and a cathode, and any components for converting the stored chemical energy into electrical energy, such as, for example, electrodes, separators, and electrolytes. In contrast, a "battery" or "battery module" refers to at least one battery cell placed in a housing having electrical connections and possible electronics for control and protection. A "battery pack" refers to an assembly of multiple batteries, in other words, a plurality of battery modules connected in series or in parallel to each other to increase the voltage or capacity, the voltage or capacity increase resulting from the series connection or parallel connection, wherein the assembly of batteries is fixed in the housing.

[0034] In this specification, the embodiments have been described in a manner that allows for a clear and concise description to be written, but it is intended and should be understood that the embodiments can be combined or separated in various ways without departing from the present invention. For example, it should be understood that all preferred features described herein are applicable to all aspects of the present invention described herein.

[0035] The present disclosure provides a double-walled enclosure for battery thermal management. The double-walled enclosure generally includes an inner hollow structure and an outer hollow structure, the inner hollow structure accommodating one or more battery modules, and the outer hollow structure surrounding or enclosing the inner hollow structure. One or more cavities are formed between the battery and the inner surface of the inner hollow structure. Similarly, at least one channel is formed between the outer surface of the inner hollow structure and the outer hollow structure. The at least one channel is configured to allow a heat transfer fluid to flow through the at least one channel to provide thermal management for the battery. The at least one channel may be located above the battery, below the battery, on one side or multiple sides of the battery, or a combination of the foregoing.

[0036] During operation, the cavity between the battery and the inner surface of the inner hollow structure can be filled with a heat transfer medium. In addition, at least one channel includes a heat transfer fluid flowing through the at least one channel. Heat generated by the battery is transferred to the inner hollow structure through the heat transfer medium, and is transferred through the inner hollow structure to the heat transfer fluid, which flows in at least one channel located between the inner hollow structure and the outer hollow structure.

[0037] Heat transfer medium can include but not limited to single-phase dielectric fluid, multiphase dielectric fluid, phase change material or the combination of above-mentioned materials.Phase change material can include but not limited to paraffin, sugar alcohol, hydrated salt or the mixture of above-mentioned materials.Multiple examples of single-phase dielectric fluid include but not limited to Kryo 51 and Kryo 20 (LAUDA Dr.R.Wobser GmbH & Co.KG, Germany) or Xenitron 3221 (Croda International PLC, Britain).An example of multiphase dielectric fluid includes but not limited to Novec 7000 (3M company, the U.S.).In the preferred design of inner hollow structure, due to the cost and weight associated with heat transfer medium, the amount of heat transfer medium necessary for filling cavity can be minimum.Those skilled in the art will appreciate that, although most designs of the double-walled shell of the present disclosure may describe this heat transfer medium as static, without exceeding the scope of the present disclosure, it is also possible to circulate this heat transfer material or make this heat transfer material flow, and.

[0038] The heat transfer fluid may include a heat transfer material that is liquid at normal ambient temperatures. The heat transfer fluid may include, but is not limited to, water, ethylene glycol, or an ethylene glycol / water mixture.

[0039] In order to promote heat transfer from the heat transfer medium to the heat transfer fluid, the inner hollow structure generally includes a polymer material so that the inner hollow structure is in thermal contact with the heat transfer fluid to provide thermal management of the battery pack. The polymer material may include an elastomer, a thermoplastic material, a thermoplastic elastomer (TPE), or a combination of the above materials. The TPE used as a polymer material may include, but is not limited to, styrene block copolymers (TPE-S), polyolefin blends (TPE-O), thermoplastic polyurethanes (TPE-U), thermoplastic copolyesters (TPE-E), thermoplastic polyamides (TPE-A), or mixtures of the above materials. Alternatively, the thermoplastic material used as a polymer material may be, but is not limited to, high-density polyethylene (HDPE), polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), or a mixture of the above materials. The polymer material is selected based on a combination of properties, including but not limited to hardness, cost, environmental impact, and a processing method that can be used to form an inner hollow structure. The type of polymer material selected for a given application will affect the wall thickness of the inner hollow structure to achieve the necessary compliance to provide the required or desired contact with the battery, heat transfer fluid, and / or the outer hollow structure.

[0040] When desired, the polymer material may have a Shore A hardness in the range of about 40 to 100, or a Shore D hardness in the range of 20 to about 75. To enhance thermal conductivity, the polymer material may be a thermally conductive polymer material. Generally, the thermally conductive polymer material may include a polymer having inherent thermal conductivity, a blend of polymers, a composite polymer material, or a combination thereof, wherein one or more polymers in the blend have inherent thermal conductivity; the composite polymer material has at least one polymer configured as a polymer matrix, wherein a thermally conductive filler is dispersed in the polymer matrix.

[0041] The polymer with intrinsic thermal conductivity can be used alone, blended with other polymers, or used as at least a part of a polymer matrix that forms part of a composite polymer material. Several examples of thermally conductive polymer materials can include, but are not limited to, thermally conductive epoxy resins, polyimides (PI), polyoxymethylene (POM), polycarbonate (PC), or other high-performance engineering polymers. When desired, the thermally conductive polymer material can include, but is not limited to, conjugated polymers with rigid conjugated backbones and strong intermolecular π-π stacking interactions, such as, for example, diamine-cured epoxy resins with liquid crystal structures that contain biphenyl functional groups. The intrinsic thermal conductivity of the thermally conductive polymer material can be enhanced by forming a specific physical structure based on crystallinity, grain size, grain (crystallite) orientation, molecular chain length, the degree to which amorphous regions connect crystallites, or by tailoring the structure of polymer chain functionality during polymer synthesis and processing.

[0042] When the thermally conductive polymer material used to form the inner hollow structure is a composite polymer material having a thermally conductive filler dispersed in a polymer matrix, the polymer matrix provides a relatively soft and flexible composite polymer material that allows efficient heat transfer. In this regard, the thermally conductive filler achieves good thermal conductivity, and the polymer matrix is ​​soft and flexible enough to directly eliminate the gap between the surface of the inner hollow structure and the battery located in the inner hollow structure and the heat transfer medium, and provide good physical contact between them, and the heat transfer medium fills any cavity formed in the inner hollow structure. Alternatively, the polymer matrix can be a harder polymer material, such as high-density polyethylene (HDPE) or polypropylene (PP), in which case the heat transfer medium fills any cavity formed therein, thereby providing good contact and heat transfer. Since the thermally conductive filler can also exhibit low electrical conductivity, the use of a composite polymer material can also effectively provide electrical insulation of the battery pack.

[0043] In addition, when a heat transfer fluid is allowed to flow through one or more channels between the inner hollow structure and the outer hollow structure, the volume change of the material used to form the inner hollow structure and the outer hollow structure may be 20% or less; alternatively, less than 15%; alternatively, about 10% or less; alternatively, no more than 5%.

[0044] Although the double-walled enclosure of the present disclosure is not as thermally conductive as conventional commercial aluminum cooling plates, the thermal conductivity provided by the polymer material of the inner hollow structure and the presence of the heat transfer medium and heat transfer fluid can provide the necessary or desired performance for thermal management of the battery pack while also directly providing the required electrical insulation without the need for additional insulating layers as required when using conventional aluminum cooling plates. In addition, the double-walled enclosure formed in accordance with the teachings of the present disclosure has the following additional advantages over conventional cooling plates: lower manufacturing costs, lighter weight, easier assembly, reduced likelihood of short circuits within the battery pack, and easier recycling in some cases (for example, compared to the use of adhesive layers and polymer pads). The process of forming the double-walled enclosure provides commercial feasibility for the production of products for small volume markets because the process of forming the double-walled enclosure requires a lower investment cost than the manufacturing process associated with conventional cooling plates, which investment cost is primarily derived from differences in tooling.

[0045] For purposes of the present disclosure, the terms "about" and "substantially" as used herein with respect to measurable values ​​and ranges refer to expected variations known to those skilled in the art (eg, limitations and variability in measurements).

[0046] For the purposes of this disclosure, the terms "at least one" element and "one or more" elements may be used interchangeably and may have the same meaning. These terms may include a single element or multiple elements, and may also be represented by the suffix "(s)" at the end of the element. For example, "at least one channel", "one or more channels" and "channel (s)" may be used interchangeably and are intended to have the same meaning.

[0047] Reference now Figure 1A and Figure 1B , the battery pack 1 is shown to have one or more battery modules 10, each of which has a positive terminal 15 (+) and a negative terminal 15 (-), which are located in a double-walled housing 3. Figure 1B In the figure, a cross-sectional view taken along the axis x is shown. Figure 1A The double-walled housing 3 generally includes an inner hollow structure 7 or shell and an outer hollow structure 5 or shell that surrounds or encloses the inner hollow structure 7. One or more battery modules 10 are located within the inner hollow structure 7. One or more cavities 20 may be formed between the battery 10 and the inner surface 8 of the inner hollow structure 7, and the cavity 20 may be filled with a heat transfer medium 22. The one or more cavities 20 may partially surround the entire battery 10, or may be partially surrounded by a heat transfer medium 22. Figure 1B It is shown around the entire circumference of the battery 10. Furthermore, at least one channel 25 is formed between the outer surface 9 of the inner hollow structure 7 and the inner surface 6 of the outer hollow structure 5. The at least one channel 25 may be filled with a heat transfer fluid 27.

[0048] like Figure 1A and Figure 1B As shown, in order to more fully illustrate the structure and purpose of the double-walled housing 3, at least one channel 25 is depicted in several figures herein as being located above the battery 10 or battery module 10. At a location between the inner hollow structure 7 and the outer hollow structure 5 where the channel 25 is not present, the outer surface 8 of the inner hollow structure 7 is in contact with the inner surface 6 of the outer hollow structure 5. However, now referring to Figure 2A , at least one channel 25 may be reversed so that at least one channel 25 is located below the battery 10 or battery module 10, or is located above and below the battery 10 at the same time. Figure 2B As shown, when a particular application requires or desires, at least one channel 25 can be located on one or more sides of the battery 10 or battery module 10 in the battery pack 1. Therefore, at least one channel 25 can be located above, below, on one or more sides of the battery 10, or a combination of the above situations without exceeding the scope of the present disclosure.

[0049] Still reference Figure 1A , Figure 1B , Figure 2A and Figure 2B , the use of a polymer material to form the inner hollow structure 7 provides sufficient ability to enable the inner surface 9 of the inner hollow structure 7 to conform to and establish contact with the battery 10, thereby overcoming any surface roughness or unevenness that may be inherently present, and / or, to enable the inner surface 9 of the inner hollow structure 7 to fully contact the heat transfer medium 22 present in any cavity 20 formed between the battery 10 and the inner surface 9 of the inner hollow structure 7. In addition, the outer surface 9 of the inner hollow structure 7 is capable of maintaining at least 50% surface contact with the heat transfer fluid 27, which is in at least one channel 25 between the inner hollow structure 7 and the outer hollow structure 5. Alternatively, the surface contact of the inner hollow structure 7 with the heat transfer fluid 27 is maintained between 50% and 100%; alternatively, greater than 50% and less than 100%; alternatively, between 55% and 95%; alternatively, about 60% to about 90%. For the purposes of this disclosure, the term "between" is intended to include the limits specified for the stated range.

[0050] Reference now Figure 3 , the inner hollow structure 7 may include one or more structural elements 30, 35 configured to support the weight of the battery or to serve as a buffer stop that assists in placing and retaining the battery. The composition of the one or more structural elements 35 may be the same as that of the inner hollow structure 7. Alternatively, the composition of the one or more structural elements 30 may be different from that of the inner hollow structure 7. The one or more structural elements 30, 35 may be integrally formed with the inner hollow structure or formed as an insert that is then attached to the inner hollow structure 7.

[0051] For the purposes of the present disclosure, the term "integrally formed" or "formed as one" means that one or more structural elements 35 and the inner hollow structure 7 are formed or molded as a single component, and / or one or more structural elements 30 and the inner hollow structure 7 are formed separately and then joined together to form a "leak-free" hollow structure 7 by using one or more of ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding and overmolding processes. Alternatively, one or more structural elements 35 are formed as a single component. Any process known to those skilled in the art that is capable of forming a single component from a polymer material, such as, for example, but not limited to, injection molding or blow molding, can be used. Similarly, the inner hollow structure 7 and the outer hollow structure 5 can be integrally formed by, but not limited to, using the following technology: such as the "ship in a bottle" (SIB) technology or the "tank advanced process technology" (TAPT) performed by blow molding. More information about SIB or TAPT can be found in U.S. Publication Nos. 2005 / 0040566A1, 2005 / 0040567A1, and 2021 / 0379811A1, each of which is incorporated herein by reference in its entirety. Using TAPT provides the additional advantage that the battery pack is not exposed to heat during the blow molding process.

[0052] The inner hollow structure 7 is formed with a wall thickness in the range of about 0.3 mm (millimeter) to about 2.5 mm. Alternatively, the wall thickness can be in the range of about 0.5 mm to about 2.3 mm; alternatively, in the range of about 1.0 mm to about 2.0 mm. Similarly, the wall thickness of the outer hollow structure 5 is in the range of about 1.0 mm to about 5.0 mm; alternatively, in the range of about 1.5 mm to about 4.0 mm, to provide structural integrity for the double-walled housing 3. Depending on the structural design and manufacturing parameters for a given application, the wall thickness of the top, bottom and / or side of the inner hollow structure 7 and / or the outer hollow structure 5 can be the same or different. For example, the choice of wall thickness can vary according to the thickness required to provide sufficient rigidity to support the weight of the battery and to maintain the stress level in the structure of the inner hollow structure 7 and / or the outer hollow structure 5, which is lower than the yield stress of one or more materials used to form the structures 5, 7.

[0053] Reference now Figure 4A and 4B , providing Figure 1A and Figure 1BA battery pack 1 similar to the battery pack 1 shown, wherein at least one angled structural support 50 separates one or more channels 25 so that the fluid transfer fluid 27 flows in multiple directions. Those skilled in the art will understand that a solid structural support may be used in place of the angled structural support 50 without exceeding the scope of the present disclosure. However, depending on the type of process selected for forming the outer hollow structure 5 (e.g., blow molding, etc.), such an angled structural support 50 design may be desirable. The use of an angled structural support 50 design creates a small area a between the outer surface 9 of the inner hollow structure 7 and the heat transfer fluid 27, where very limited heat transfer will occur due to the lack of thermal contact. The presence of this small area a does not affect the performance of the double-walled housing 3 in providing thermal management of the battery 10.

[0054] Reference now Figure 5 , showing that in Figure 4A and Figure 4B A partial perspective view of the battery pack 1 obtained in the region of one or more channels 25. Figure 5 , the contour of the outer surface 9 of the inner hollow structure 7 shows at least one feature 40, which rises from the outer surface 9 of the inner hollow structure 7 and protrudes into at least one channel 25 to provide additional rigidity and guide or control the flow of the heat transfer fluid 27. Those skilled in the art will understand that one or more features 40 may protrude from the outer surface 9 of the inner hollow structure 7 (as shown in FIG. 4 ), from the inner surface 6 of the outer hollow structure 5, or from both surfaces 6, 9 into the one or more channels 25 without exceeding the scope of the present disclosure. The shape of the feature 40 may be any shape, including but not limited to cylindrical, elongated, or angular. The number of features 40, the shape of the features 40, and the location of the features 40 are selected to provide the desired flow and / or mixing of the heat transfer fluid 27 in the one or more channels 25. Figure 5 , flow path (→) provides for fluid mixing in the presence of features 40 protruding into one or more channels 25. Heat transfer fluid 27 may include any type of heat transfer liquid including, but not limited to, water, glycol, or a water / glycol mixture.

[0055] When the inner hollow structure 7 is formed of a thermally conductive polymer material including a composite polymer material, the composite polymer material generally includes, consists essentially of, or includes a thermally conductive filler dispersed in a polymer matrix. The thermally conductive filler may also exhibit a low degree of electrical conductivity to assist in the electrical insulation of the battery. For purposes of the present disclosure, the low degree of electrical conductivity exhibited by the thermally conductive filler is defined as approximately 9.9 x 10 5 S / m or less; alternatively, approximately 9.9 x 10 4S / m or less. Alternatively, the electrical conductivity of the thermally conductive filler is low enough that the filler is classified as an electrical insulator.

[0056] The thermally conductive filler includes a plurality of particles, the components of which include boron nitride, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, graphene, graphite, carbon nanotubes (single-walled or multi-walled) or a mixture of the above ingredients. The particles can have any feasible shape, including but not limited to spherical, flat (e.g., flakes), irregular or elongated (e.g., fibers). The particles can also be described as being in any feasible crystal form that provides thermal conductivity. Alternatively, when boron nitride is used as a thermally conductive filler, boron nitride provides a desired degree of thermal conductivity and electrical insulation for use in many applications. When boron nitride (BN) particles are used as thermally conductive fillers, the boron nitride (BN) particles can include boron nitride in hexagonal crystal form (H-BN) or boron nitride in cubic crystal form (C-BN); alternatively, the thermally conductive filler is H-BN.

[0057] The polymer matrix may include an elastomer, thermoplastic material, or thermoplastic elastomer (TPE) having a Shore A hardness in the range of about 40 to 100, or a Shore D hardness in the range of 20 to about 75. Alternatively, the polymer matrix is ​​a thermoplastic elastomer (TPE) having a Shore A hardness in the range of about 50 to about 90, or a Shore D hardness in the range of about 45 to about 75; alternatively, a Shore A hardness in the range of about 70 to about 80. The polymer matrix may be used in accordance with ASTM D22440 00, ISO 7619 and ISO 868; DIN 53505; and / or JIS K 6301. (Durometer) test to measure Shore A hardness and / or Shore D hardness, JIS K 6301 has been superseded by JIS K 6253. Alternatively, the polymer matrix is ​​a thermoplastic material having a Shore D hardness in the range of about 60 to 75.

[0058] According to one aspect of the present disclosure, the composition of the composite polymer material 70 includes a plurality of boron nitride particles dispersed in a thermoplastic elastomer (TPE) having a Shore A hardness in a range of about 70 to about 80.

[0059] The thermally conductive filler may be dispersed in the polymer matrix using any mixing technique known for dispersing solid particles into liquid polymers. After mixing, the thermally conductive filler comprises between about 5 wt.% and about 30 wt.% of the total weight of the composite polymer material. Alternatively, the thermally conductive filler comprises between about 5 wt.% and about 25 wt.% of the total weight of the composite polymer material; alternatively, between about 10 wt.% and about 20 wt.% of the total weight of the composite polymer material.

[0060] The outer hollow structure 5 is formed of a "hard" polymer to provide physical or mechanical protection for the battery pack. The outer hollow structure may include, but is not limited to, high-density polyethylene (HDPE), polypropylene (PP), polyamide (PA), or a combination of the above materials, which are copolymers, polymer blends / mixtures, or multilayer structures or composite materials. The outer hollow structure may also include a variety of fillers, such as fiber or particle reinforcement materials (e.g., glass, carbon, etc.) to enhance structural performance and provide thermal runaway mitigation.

[0061] According to another aspect of the present disclosure, a battery pack with thermal management is provided. Referring again to FIGS. 1 to 2 Figure 5 The battery pack 1 generally includes at least one battery 10 and a double wall housing 3 configured as previously described and as further defined herein. The double wall housing 3 can be used to provide thermal management for at least one battery 10 in an electric vehicle (EV) or a hybrid electric vehicle (HEV).

[0062] Reference now Figure 6 According to another aspect of the present disclosure, a process 100 for forming a battery pack as previously described and as otherwise defined herein is provided. The process 100 generally includes the following steps: 105-providing a polymer material; 110-molding an inner hollow structure with the polymer material, the inner hollow structure having an outer surface and an inner surface; 115-molding an outer hollow structure, the outer hollow structure having an inner surface, the inner surface surrounding the outer surface of the inner hollow structure, wherein the outer surface of the inner hollow structure is either in contact with the inner surface of the outer hollow structure or forms at least one channel with the inner surface of the outer hollow structure; 120-providing at least one battery; 125-assembling at least one battery in the inner hollow structure, wherein one or more cavities are formed between the battery and the inner surface of the inner hollow structure; 130-filling the one or more cavities with a heat transfer medium; and 135-allowing the heat transfer fluid to flow through at least one channel, the at least one channel being located between the inner surface of the outer hollow structure and the outer surface of the inner hollow structure. The molding process 110 , 115 used in the process 100 may be selected from one of the group consisting of blow molding, injection molding, compression molding, rotational molding, or a combination of the above processes.

[0063] When desired, the process 100 may also include: 140-forming one or more structural elements present in the inner hollow structure to assist in supporting the weight of the battery or battery module or to serve as a buffer stop for placing and retaining such a battery. These structural elements may be formed by a molding process such as, for example, blow molding using a "ship in a bottle" (SIB) technique or "tank advanced process technology" (TAPT).

[0064] When desired, the process 100 may also include: 145A, 145B-forming one or more features, 145B-the one or more features protruding from the inner surface of the outer hollow structure into the at least one channel, or 145A-the one or more features protruding from the outer surface of the inner hollow structure into the at least one channel to increase stiffness and / or promote fluid mixing by directing fluid flow. The additional forming steps 145A, 145B are typically incorporated into the molding processes 110, 115 by including additional steps in the molding process, such as by using 3-D printing or positioning the insert in the mold.

[0065] When desired, step 125 of assembling at least one battery in the inner hollow structure can be accomplished by using a "ship in a bottle" technique or Tank Advanced Process Technology (TAPT) in combination with 110-molding the inner hollow structure during a blow molding process. Alternatively, assembly 125 can include placing one or more battery modules into an inner hollow structure having an opening. After placing the battery, the opening is then closed to form a "leak-free" hollow structure by using one or more of ultrasonic welding, spin welding, vibration welding, hot plate welding, infrared welding, laser welding, and overmolding techniques. The one or more battery modules placed into the inner hollow structure may include any known battery cell form, including but not limited to prismatic, cylindrical, pouch-shaped, or a combination of the foregoing shapes.

[0066] Those skilled in the art will understand that, as described above and Figure 6 The process steps in the methods described in, and the process steps otherwise defined herein, are not limited to being performed in the order listed, but rather the process steps may be performed in any desired or required order depending on the choice of materials and the manufacturing equipment and manufacturing techniques selected for processing the materials. Each of the process steps may be performed sequentially or simultaneously, for example, a step may be combined with another process step and run simultaneously, or as part of another process step. Alternatively, when desired, the process steps may be performed in the order provided.

[0067] According to the present disclosure, it will be appreciated by those skilled in the art that many changes can be made to the specific embodiments disclosed herein and still the same or similar results can be obtained without departing from or exceeding the spirit or scope of the present disclosure. It will also be appreciated by those skilled in the art that any characteristic reported herein represents a characteristic that is conventionally measured and can be obtained by a variety of different methods. The method described herein represents one such method and other methods can be used without exceeding the scope of the present disclosure.

[0068] The above description of various forms of the present invention is presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed. In light of the above teachings, many modifications or variations are possible. The forms discussed are selected and described to provide the best illustration of the principles of the present invention and its practical application, so that a person of ordinary skill in the art can utilize the present invention in various forms and make various modifications to adapt to the specific intended use. Therefore, the present invention is not limited to the above preferred exemplary embodiments in practice. On the contrary, many variations can be envisioned, which even utilize the described solutions in fundamentally different embodiments. All these modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted according to the scope to which they are fairly, legally and equitably entitled.

Claims

1. A double-walled enclosure for thermal management of a battery pack, the enclosure comprising: an inner hollow structure, the inner hollow structure having an inner surface and an outer surface; One or more battery modules are positioned in the inner hollow structure; as well as an outer hollow structure, the outer hollow structure having an inner surface, wherein the outer surface of the inner hollow structure either contacts the inner surface of the outer hollow structure or forms at least one channel with the inner surface of the outer hollow structure, and a heat transfer fluid flows through the at least one channel; Wherein, the inner hollow structure comprises a polymer material, so that the inner hollow structure is in thermal contact with the heat transfer fluid to provide thermal management of the battery pack.

2. The housing according to claim 1, wherein: The wall thickness of the inner hollow structure is in the range of about 0.3 mm (millimeter) to about 2.5 mm; Wherein, the wall thickness of the outer hollow structure is in the range of about 1.0 mm to about 5.0 mm.

3. The housing according to claim 1 or 2, wherein: forming one or more cavities between the one or more battery modules and the inner surface of the inner hollow structure; Therein, the one or more cavities are at least partially filled with a heat transfer medium.

4. The housing according to claim 3, wherein: The heat transfer medium in the one or more cavities is a single-phase dielectric fluid, a multi-phase dielectric fluid, a phase change material, or a combination of the above materials; Wherein, the heat transfer fluid in the at least one channel is water, ethylene glycol or a water / ethylene glycol mixture.

5. The housing according to any one of claims 1 to 4, wherein: The polymer material includes an elastomer, a thermoplastic material, a thermoplastic elastomer (TPE), or a combination of the above materials.

6. The housing according to any one of claims 1 to 5, wherein: The polymer material has a Shore A hardness in the range of about 40 to 100, or the polymer material has a Shore D hardness in the range of about 20 to about 75.

7. The housing according to any one of claims 1 to 6, wherein: The polymer material is a thermally conductive polymer material.

8. The housing according to claim 7, wherein: The thermally conductive polymer material includes a polymer having inherent thermal conductivity, a blend of polymers, a composite polymer material, or a combination of the above materials, wherein one or more polymers in the blend have inherent thermal conductivity, and the composite polymer material has at least one polymer configured as a polymer matrix, and a thermally conductive filler is dispersed in the polymer matrix.

9. The housing according to claim 8, wherein: The thermally conductive filler comprises a plurality of particles, and components of the plurality of particles are selected from the group consisting of boron nitride, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, graphene, carbon nanotubes, or a mixture thereof.

10. The housing according to any one of claims 1 to 6, wherein: The components of the polymer material include a composite polymer material having a plurality of boron nitride particles dispersed in a thermoplastic elastomer (TPE) matrix, wherein the Shore A hardness of the thermoplastic elastomer (TPE) matrix is ​​in the range of about 70 to about 80.

11. The housing according to any one of claims 1 to 10, wherein: The outer hollow structure comprises high-density polyethylene (HDPE), polypropylene (PP), polyamide (PA) or a combination of the above materials, wherein the combination is a copolymer, a polymer blend / mixture or a multilayer structure or a composite material.

12. The housing according to any one of claims 1 to 11, wherein The at least one channel is located above, below, at least one side, or a combination thereof relative to the one or more battery modules.

13. The housing according to any one of claims 1 to 12, wherein: The inner hollow structure includes one or more structural elements configured to support the weight of the one or more battery modules and / or to serve as a buffer stop configured to assist in placing and retaining the battery; Therein, the one or more structural elements are either formed integrally with the inner hollow structure, or are arranged as inserts connected to the inner hollow structure.

14. The housing according to any one of claims 1 to 13, wherein at least one of the outer surface of the inner hollow structure or the inner surface of the outer hollow structure comprises one or more features configured to increase stiffness and / or promote fluid mixing by directing fluid flow; Wherein at least one of the features protrudes into the at least one channel.

15. The housing according to any one of claims 1 to 15, wherein At least a portion of the outer surface of the inner hollow structure is flat, the at least a portion forming a portion of the at least one channel such that at least 50% surface contact is maintained with the heat transfer fluid in the at least one channel.

16. The housing according to any one of claims 1 to 15, wherein The inner hollow structure and the outer hollow structure produce a volume change of less than about 15% when the heat transfer fluid is allowed to flow through the at least one channel.

17. The housing according to any one of claims 7 to 9, wherein The thermally conductive polymer material includes a composite polymer material having a polymer matrix, wherein a thermally conductive filler is dispersed in the polymer matrix such that the thermally conductive filler accounts for between about 5 wt. % and about 25 wt. % of the total weight of the composite polymer material.

18. A battery pack with thermal management, wherein: The battery pack comprises: at least one battery; and A double-walled housing according to any one of claims 1 to 17; wherein the double-walled housing comprises an inner hollow structure and an outer hollow structure, the inner hollow structure having an inner surface and an outer surface; one or more battery modules are positioned in the inner hollow structure; the outer hollow structure has an inner surface, wherein the outer surface of the inner hollow structure is either in contact with the inner surface of the outer hollow structure or forms at least one channel with the inner surface of the outer hollow structure, and a heat transfer fluid flows through the at least one channel; Wherein, the inner hollow structure comprises a polymer material, so that the inner hollow structure is in thermal contact with the heat transfer fluid to provide thermal management of the battery pack.

19. The battery pack according to claim 18, wherein: The polymer material includes a thermally conductive polymer material.

20. The battery pack according to claim 19, wherein: The thermally conductive polymer material comprises a composite polymer material having a polymer matrix, wherein a thermally conductive filler is dispersed in the polymer matrix; Wherein, the thermally conductive filler comprises a plurality of particles, and the components of the plurality of particles are selected from the group consisting of: boron nitride, aluminum oxide, silicon nitride, graphene, carbon nanotubes or a mixture of the above components; wherein the polymer matrix is ​​an elastomer, a thermoplastic material or a thermoplastic elastomer (TPE), and the Shore A hardness of these elastomers, thermoplastic materials or thermoplastic elastomers (TPE) is in the range of about 40 to 100, or the Shore D hardness of these elastomers, thermoplastic materials or thermoplastic elastomers (TPE) is in the range of 20 to about 75; The thermally conductive filler accounts for between about 5 wt. % and about 25 wt. % of the total weight of the composite polymer material.

21. Use of a double wall enclosure according to any one of claims 1 to 17 for providing thermal management for one or more battery modules in an electric vehicle (EV) or hybrid electric vehicle (HEV).

22. A process for forming a battery pack configured for thermal management according to any one of claims 18 to 20, wherein: The process comprises: Providing polymer materials; Molding an inner hollow structure using the polymer material; the inner hollow structure having an outer surface and an inner surface; Molding an outer hollow structure, the outer hollow structure having an inner surface, the inner surface surrounding the outer surface of the inner hollow structure; wherein the outer surface of the inner hollow structure either contacts the inner surface of the outer hollow structure or forms at least one channel with the inner surface of the outer hollow structure; providing at least one battery; Assembling the at least one battery in the inner hollow structure, wherein one or more cavities are formed between the battery and the inner surface of the inner hollow structure; filling the one or more cavities with a heat transfer medium; and A heat transfer fluid is allowed to flow through the at least one channel, the at least one channel being located between the inner surface of the outer hollow structure and the outer surface of the inner hollow structure.

23. The process of claim 22, wherein: The molding is performed using a method selected from the group consisting of blow molding, injection molding, compression molding, rotational molding, or a combination of the above processes.

24. A process according to claim 22 or 23, wherein The process also includes: forming one or more structural elements configured to support the weight of the battery within the inner hollow structure and / or to act as a buffer stop, the one or more structural elements being composed of the same or different components than the inner hollow structure; and / or One or more features are formed, the one or more features protruding from the inner surface of the outer hollow structure into the at least one channel, or from the outer surface of the inner hollow structure into the at least one channel, the features being configured to increase stiffness and / or promote fluid mixing by directing fluid flow.

25. A process according to any one of claims 22 to 24, wherein The molding methods include the use of "ship in a bottle" (SIB) technology or tank advanced process technology (TAPT).

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