Compositions, systems, and methods for tunable mechanical performance in battery thermal barriers

Abstract

Various embodiments disclosed relate to a structural feature in a thermal barrier. The present disclosure includes a battery module having a stack of battery cells located within a module housing and a thermal barrier between at least two cells in the stack of battery cells. The thermal barrier can include an insulation layer and a structural feature distributed over the insulation layer. A thermal barrier for use in a battery module can include an insulation layer, the insulation layer configured to thermally isolate individual battery cells within the battery module; and a structural feature distributed within the insulation layer.

Description

COMPOSITIONS, SYSTEMS, AND METHODS FOR TUNABLE MECHANICAL PERFORMANCE IN BATTERY THERMAL BARRIERSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application S.N.63 / 550,262, filed February 6, 2024, the contents of which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to materials and systems and methods for mitigating thermal events, such as thermal runaway issues, in energy storage systems. In particular, the present disclosure provides thermal barrier materials. The present disclosure further relates to a battery module or pack with one or more battery cells and the thermal barrier materials, as well as systems including those battery modules or packs. The thermal barrier materials described generally may include aerogel materials.BACKGROUND

[0003] Lithium-ion batteries (LIBs) are widely used in powering portable electronic devices such as cell phones, tablets, laptops, power tools, and other high-current devices, such as electric vehicles, because of their high working voltage, low memory effects, and high energy density compared to traditional batteries. However, LIBs may be susceptible to catastrophic failure under “abuse conditions,” such as when a rechargeable battery is overcharged, over-discharged, and / or operated at or exposed to high temperature.

[0004] To mitigate cascading thermal runaway events from occurring, there is a need for effective insulation and heat dissipation strategies to address these and other technical challenges of LIBs.SUMMARY OF THE DISCLOSURE

[0005] In an aspect, a battery module comprises a stack of battery cells located within a module housing; a thermal barrier between at least two cells in the stack of battery cells, the thermal barrier having a first major surface, a second major surface on a side opposing the first major surface, and a thickness extending between the first major surface and the second major surface; and a structural feature distributed over the thermal barrier, the structural feature comprising a plurality of elements, where the plurality of elements modify the compressibility of the thermal barrier.

[0006] In an aspect, the plurality of elements comprises one or more of cylinders, spheres, hemispheres, pyramids, rods, bars, dots, and irregular geometrical shapes.

[0007] In an aspect, the plurality of elements comprises at least one of polymers, rubber, resin, foam, and combinations thereof.

[0008] In an aspect, a method of making a structural feature in a thermal barrier can include removing a portion of the thermal barrier to form one or more cavities; and forming the structural feature in the one or more cavities.

[0009] In an aspect, a method of making a structural feature in a thermal barrier comprising an insulation layer can include forming the structural feature and inserting the aerogel in and around the structural feature.

[0010] In an aspect, a method of providing a structural feature in a thermal barrier comprising an insulation layer can include forming the structural feature on a layer or layers disposed on or adjacent to a surface of the insulation layer.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, byway of aspect, but not by way of limitation, various embodiments discussed in the present document.

[0012] FIG. 1 A illustrates a perspective view of a battery module in an aspect.

[0013] FIG. IB depicts a cross-sectional view, taken along line A-A’ of Fig. 1A, of the battery module.

[0014] FIG. 2A depicts a perspective view of an aspect of a battery module with battery cells and thermal barriers.

[0015] FIG. 2B depicts a perspective view of an aspect of the thermal barrier of FIG.2A.

[0016] FIG. 2C depicts a desired curve (solid line) and an undesired curve (dashed line) of force (N, Y axis) relative to thickness (mm, X axis).

[0017] FIGS. 3A-3N each illustrates a side view of different aspects of a thermal barrier with structural features.

[0018] FIG. 30 illustrates a perspective view of a thermal barrier with pyramid shaped structural features.

[0019] FIG. 3P illustrates a front view of a thermal barrier with pyramid shaped structural features.

[0020] FIGS. 3Q-3R illustrate front views of structural features disposed on carrying sheets.

[0021] FIG. 3S illustrates a prospective view of a thermal barrier and structural features prior to assembly.

[0022] FIG. 3T illustrates a prospective view of a thermal barrier and structural features after assembly.

[0023] FIGS. 4A-4C depict an aspect of how structural features can be applied to an aerogel in a thermal barrier.

[0024] FIGS. 5A-5D depict aspects of thermal barriers with various structural features.

[0025] FIGS. 5E-5H depict aspects of thermal barriers with frame shaped structural features.

[0026] FIGS. 6A-6C illustrate cross-sectional views of different aspects of a thermal barrier with curved ribbon structural features extending through a thickness of the thermal barrier.

[0027] FIGS. 7A-7C illustrate side views (7A and 7B) and a front view (7C) of different aspects of a thermal barrier with flexible fiber structural features.

[0028] FIGS. 8A-8B illustrate various views of an aspect of a thermal barrier with heat pressed structural features.

[0029] FIGS. 9A-9B illustrate views of another aspect of a thermal barrier with a structural feature.

[0030] FIGS. 10A-10C illustrate views of yet another aspect of a thermal barrier having a structure feature that is heat pressed.

[0031] FIG. 11 illustrates a flow chart of a method of making a thermal barrier with a structural feature in an aspect.DETAILED DESCRIPTIONOverview

[0032] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0033] The present disclosure describes, among other things, systems and methods related to thermal barrier for battery modules. The thermal barriers can be aerogel-based thermal barriers, such as for within or around battery modules. Discussed herein, among otherthings, is the creation and use of a structural feature (or features) within such thermal barriers to impart shear strength and compressibility to the thermal barriers.

[0034] Thermal barriers, which can include thermally insulative layers and structures, can be used in battery modules to help regulate temperature and heat flow within such battery modules. In one aspect, lithium-ion batteries, often used in a stack of many battery cells, can benefit from thermal regulation to prevent thermal runaway, which could cause potential fires, overheating, combustion, or other issues associated with high temperatures in such a battery module.

[0035] Such thermal barriers include thermal insulation materials as discussed in detail below, such as aerogel materials. Insulation materials according to exemplary embodiments disclosed herein include ceramic materials, e.g., ceramic papers; mica materials; polymer foam materials, e.g., polyurethane foams, polyisocyanurate foam, polystyrene foam, and phenolic foam; polymer sheet materials, e.g., polypropylene sheets, polystyrene sheets, and polyisocyanurate sheets; microporous silica; ceramic fiber; mineral wool; multi-layer materials including insulative, conductive and / or compression elements; fiber glass; rubber; cementitious foam; perlite materials; and combinations thereof. These materials, while providing thermal benefits, can suffer from mechanical stress, such as within a battery cell stack. In this case, a thermal barrier is situated, in one aspect, between two battery cells. In this situation, the thermal barrier may be subjected to a compressive force. The compressive force, in some aspects, may be cyclical as the battery cells confronting the major surfaces of the thermal barrier expand and contract during battery electrical charge / discharge cycles.

[0036] These compressive forces may be problematic for several reasons. In one aspect, unless the expansion of the cells is limited, electrolyte within the cells may pool and lose contact with active material within the cell, thereby leading to decreased cell performance. In another aspect, the thermal barriers may be subject to enough pressure or enough cycles of pressure that the thermal barriers are damaged from the (repeated) compression.

[0037] As described herein, structural features disposed on, around, and / or within thermal barriers may improve the ability of the thermal barriers to withstand compressive forces from adjacent cells. These structural features may impart to the thermal barrier improved resistance to compressive forces and / or be used to select and / or fine tune a specific desired response to compression of the thermal barrier.

[0038] The structural features can, in one aspect, include spheres, hemispheres, diamond shapes, pyramid shapes, dots, rods, tubes, lattices, nets, ribbons, frames, or other appropriate shapes that modify the compressibility of the thermal barrier. These structural features can be, in one aspect, created first, and the aerogel inserted there around. Or, in another aspect, these structural features can be formed on, around, or within an already formed aerogel. These structural features can, in one aspect, be made of polymer or plastic materials, or dielectric materials. Some specific aspects of these materials include polyimides, polycarbonates, polyester, or other appropriate materials with appropriate mechanical, electrical and thermal properties.Insulation materials

[0039] The thermal barrier insulation materials, as described in aspects below, can be used as a single heat-resistant layer, or in combination with other layers that provide additional function to a multilayer configuration, such as mechanical strength, compressibility, heat dissipation / conduction, etc. Insulation layers described herein are responsible for reliably containing and controlling heat flow from heat-generating parts in small spaces and to provide safety and prevention of fire propagation for such products in the fields of electronic, industrial, and automotive technologies.

[0040] In many embodiments of the present disclosure, the insulation layer functions as a flame / fire deflector layer either by itself or in combination with other materials that enhance performance of containing and controlling heat flow. In one aspect, the insulation layer mayitself be resistant to flame and / or hot gases and further include entrained particulate materials that modify or enhance heat containment and control.

[0041] In one aspect, a highly effective insulation layer includes an aerogel. Aerogels describe a class of material based upon their structure, namely low density, open cell structures, large surface areas (often 900 m2 / g or higher) and sub nanometer scale pore sizes. The pores may be fdled with gases, such as air. Aerogels can be distinguished from other porous materials by their physical and structural properties. Although an aerogel material is an exemplary insulation material, the aspects set forth herein are not so limited. Other thermal insulation material layers may also be used in aspects of the present disclosure.

[0042] Selected aspects of aerogel formation and properties are described. In several aspects, a precursor material is gelled to form a network of pores that are filled with solvent. The solvent is then extracted, leaving behind a porous matrix. A variety of different aerogel compositions are known, and they may be inorganic, organic, or inorganic / organic hybrid. Inorganic aerogels are generally based upon metal alkoxides and include materials such as silica, zirconia, alumina, and other oxides. Organic aerogels include, but are not limited to, urethane aerogels, resorcinol formaldehyde aerogels, and polyimide aerogels.

[0043] Inorganic aerogels may be formed from metal oxide or metal alkoxide materials. The metal oxide or metal alkoxide materials may be based on oxides or alkoxides of any metal that can form oxides. Such metals include, but are not limited to, silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, cerium, and the like. Inorganic silica aerogels are traditionally made via the hydrolysis and condensation of silica-based alkoxides (such as tetraethoxylsilane), or via gelation of silicic acid or water glass. Other relevant inorganic precursor materials for silica based aerogel synthesis include, but are not limited to, metal silicates such as sodium silicate or potassium silicate, alkoxysilanes, partially hydrolyzed alkoxysilanes, tetraethoxylsilane (TEOS), partially hydrolyzed TEOS, condensed polymers of TEOS, tetramethoxylsilane (TMOS), partially hydrolyzed TMOS, condensed polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzed and / or condensed polymers of tetra-n-propoxysilane, polyethylsilicates, partially hydrolyzed polyethysilicates, monomeric alkylalkoxy silanes, bis-trialkoxy alkyl or aryl silanes, polyhedral silsesquioxanes, or combinations thereof.

[0044] In certain embodiments of the present disclosure, pre-hydrolyzed TEOS, such as Silbond H-5 (SBH5, Silbond Corp), which is hydrolyzed with a water / silica ratio of about 1.9- 2, may be used as commercially available or may be further hydrolyzed prior to incorporation into the gelling process. Partially hydrolyzed TEOS or TMOS, such as polyethysilicate (Silbond 40) or polymethylsilicate may also be used as commercially available or may be further hydrolyzed prior to incorporation into the gelling process.

[0045] Inorganic aerogels can also include gel precursors comprising at least one hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metal alkoxides, and aryl metal alkoxides, which can impart or improve certain properties in the gel, such as stability and hydrophobicity. Inorganic silica aerogels can specifically include hydrophobic precursors, such as alkylsilanes or arylsilanes. Hydrophobic gel precursors may be used as primary precursor materials to form the framework of a gel material. However, hydrophobic gel precursors are more commonly used as co-precursors in combination with simple metal alkoxides in the formation of amalgam aerogels. Hydrophobic inorganic precursor materials for silica based aerogel synthesis include, but are not limited to, trimethyl methoxysilane (TMS), dimethyl dimethoxysilane (DMS), methyl trimethoxysilane (MTMS), trimethyl ethoxysilane, dimethyl di ethoxy silane (DMDS), methyl triethoxysilane (MTES), ethyl triethoxysilane (ETES), diethyl di ethoxy silane, dimethyl di ethoxy si lane (DMDES), ethyl tri ethoxy si lane, propyl trimethoxysilane, propyl triethoxysilane, phenyl trimethoxysilane, phenyl triethoxysilane (PhTES), hexamethyldisilazane and hexaethyldisilazane, and the like. Any derivatives of any of the above precursors may be used; and specifically, certain polymeric or other chemical groups may be added or cross-linked to one or more of the above precursors.

[0046] Organic aerogels are generally formed from carbon-based polymeric precursors. Such polymeric materials include, but are not limited to, resorcinol formaldehydes (RF),polyimide, polyacrylate, polymethyl methacrylate, acrylate oligomers, polyoxyalkylene, polyurethane, polyphenol, polybutadiane, trialkoxysilyl-terminated polydimethylsiloxane, polystyrene, polyacrylonitrile, polyfurfural, melamine-formaldehyde, cresol formaldehyde, phenol -furfural, polyether, polyol, polyisocyanate, polyhydroxybenze, polyvinyl alcohol dialdehyde, polycyanurates, polyacrylamides, various epoxies, agar, agarose, chitosan, and combinations thereof. As one aspect, organic RF aerogels are typically made from the sol-gel polymerization of resorcinol or melamine with formaldehyde under alkaline conditions.

[0047] Organic / inorganic hybrid aerogels are mainly comprised of organically modified silica (“ormosil”) aerogels. These ormosil materials include organic components that are covalently bonded to a silica network. Ormosils are typically formed through the hydrolysis and condensation of organically modified silanes, R— Si(OX)3, with traditional alkoxide precursors, Y(0X)4. In these formulas, X may represent, in one aspect, CH3, C2H5, C3H7, C4H9; Y may represent, in one aspect, Si, Ti, Zr, or Al; and R may be any organic fragment such as methyl, ethyl, propyl, butyl, isopropyl, methacrylate, acrylate, vinyl, epoxide, and the like. The organic components in ormosil aerogel may also be dispersed throughout or chemically bonded to the silica network.

[0048] Aerogels can be formed from flexible gel precursors. Various flexible layers, including flexible fiber-reinforced aerogels, can be readily combined, and shaped to give preforms that when mechanically compressed along one or more axes, give compressively strong bodies along any of those axes.

[0049] One method of aerogel formation includes batch casting. Batch casting includes catalyzing one entire volume of sol to induce gelation simultaneously throughout that volume. Gel-forming techniques include adjusting the pH and / or temperature of a dilute metal oxide sol to a point where gelation occurs. Suitable materials for forming inorganic aerogels include oxides of most of the metals that can form oxides, such as silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, and the like. Particularly preferred are gels formed primarily from alcohol solutions of hydrolyzed silicate esters due to their ready availability andlow cost (alcogel). Organic aerogels can also be made from melamine formaldehydes, resorcinol formaldehydes, and the like.

[0050] In one aspect, aerogel materials may be monolithic, or continuous throughout a structure or layer. In other aspects, an aerogel material may include a composite aerogel material with aerogel particles that are mixed with a binder. Other additives may be included in a composite aerogel material, including, but not limited to, surfactants that aid in dispersion of aerogel particles within a binder. A composite aerogel slurry may be applied to a supporting plate such as a mesh, felt, web, etc. and then dried to form a composite aerogel structure.Reinforcement

[0051] As noted above, an aerogel may be organic, inorganic, or a mixture thereof. In some aspects, the aerogel includes a silica-based aerogel. One or more layers in a thermal barrier may include reinforcement material (also referred to herein as a reinforcing material). The reinforcing material may be any material that provides resilience, conformability, or structural stability to the aerogel material. Aspects of reinforcing materials include, but are not limited to, open-cell macroporous framework reinforcement materials, closed-cell macroporous framework reinforcement materials, open-cell membranes, honeycomb reinforcement materials, polymeric reinforcement materials, and fiber reinforcement materials such as discrete fibers, woven materials, non-woven materials, needled non-wovens, battings, webs, mats, and felts.

[0052] The reinforcement material can be selected from organic polymer-based fibers, inorganic fibers, carbon-based fibers, or a combination thereof. The inorganic fibers are selected from glass fibers, rock fibers, metal fibers, boron fibers, ceramic fibers, basalt fibers, or combination thereof. In some aspects, the thermal barrier can include a plurality of layers of reinforcement material.Thermally conductive layers

[0053] In addition to thermal insulating layers, the thermal barrier may optionally include thermal conductive layers. The thermally conductive layers in combination with thermal insulating layers are effective at channeling unwanted heat to a desired external location, such as external heat dissipating fins, a heat dissipating housing, or another external structure to dissipate unwanted heat to outside ambient air. In one aspect, a thermally conductive layer or layers helps to dissipate heat away from a localized heat load within a battery module or pack. Aspects of high thermal conductivity materials include carbon fiber, graphite, silicon carbide, metals or metal alloys (including, but not limited to, copper, stainless steel, aluminum, and the like), as well as combinations thereof.

[0054] To aid in the distribution and removal of heat by, in at least one embodiment, the thermally conductive layer may be coupled to a heat sink. It will be appreciated that there are a variety of heat sink types and configurations, as well as different techniques for coupling the heat sink to the thermally conductive layer, and that the present disclosure is not limited to the use of any one type of heat sink and / or coupling technique. In one aspect, at least one thermally conductive layer of the multilayer materials disclosed herein can be in thermal communication with an element of a cooling system of a battery module or pack, such as a cooling plate or cooling channel of the cooling system. For another aspect, at least one thermally conductive layer of the multilayer materials disclosed herein can be in thermal communication with other elements of the battery pack, battery module, or battery system that can function as a heat sink, such as the walls of the pack, module, or system, or with other elements of the multilayer materials disposed between battery cells. Thermal communication between the thermally conductive layer of the multilayer materials and heat sink elements within the battery system can allow for removal of excess heat from the cell or cells adjacent to the multilayer material to the heat sink, thereby reducing the effect, severity, or propagation of a thermal event that may generate excess heat. In addition to removal of heat, a thermallyconductive layer can spread, or dissipate, heat from a region of high heat concentration to a larger region of lower heat concentration.Resilient Layers

[0055] In addition to thermal insulating layers and thermal conductive layers, the thermal barrier may optionally further comprise one or more resilient material layers. In one example, a resilient layer absorbs any volume expansion during the regular operation of one or more battery cells. For example, during a charge, the battery cells may expand, and during a discharge, the battery cells may shrink. In one example, the resilient layer may also absorb permanent volume expansion caused by any battery cell degradation and / or thermal runaway. Resilient material layers may include, but are not limited to, foam, fiber, fabric, sponge, spring structures, rubber, polymer, etc.

[0056] Within the context of the present disclosure, the terms “resilient” and “resilience” refer to the ability of an aerogel material or composition to return to an original form or dimension following deformation at least partially through compression, flexing, or bending. Resilience may be complete or partial, and it may be expressed in terms of percentage return. An aerogel material or composition of the present disclosure preferably has a resilience of more than 25%, more than 50%, more than 60%, more than 70%, more than 75%, more than 80%, more than 85%, more than 90%, or more than 95% return to an original form or dimension following a deformation. Likewise, the terms “classified resilient” and “classified as resilient” refer to aerogel materials or compositions of the present disclosure which can be classified as “resilient flexible” according to ASTM classification standard Cl 101 (ASTM International, West Conshohocken, PA).Structural Features

[0057] Aspects of the thermal barrier herein include, at a minimum, one or more thermal insulating layers and structural features. Beyond these minimum elements, otherexamples may optionally include one or more of a resilient layer and a conductive layer (or multiple layers thereof). The structural features contribute to the compressibility of the thermal barrier as a whole, particularly when the compressibility and resilience behavior of the structural features and the one or more thermal insulating layers are considered together as an integrated system.

[0058] In some aspects, the structural features alter the compressibility behavior of the thermal barrier to values that would not be exhibited by the insulating layer(s) alone.Compressibility is a measure of the relative volume change of the thermal barrier in response to a pressure change. When the area of the thermal barrier is fixed, compressibility is a measure of the relative thickness change of the thermal barrier response to an applied force (e.g., a change in applied force). Desired compressibility allows a change in thickness from about 2 mm to about 0.2 mm when the applied force increases from about 4000 N to about 80000 N, a change in thickness from about 1.5 mm to about 0.2 mm when the applied force increases from about 5000 N to about 50000 N, or a change in thickness from about 1.25 mm to about 0.3 mm when the applied force increases from about 7000 N to about 35000 N, or a change in thickness from about 1 mm to about 0.4 mm when the applied force increases from 8000 N to 25000 N. These values are generally not achievable for insulation materials that also exhibit other desired thermal barrier characteristics (e.g., a thermal conductivity of less than 40 mW / m-K, a liquid water uptake of less than 40%, and an onset of thermal decomposition of above 500°C).

[0059] The compressibility of the thermal barrier is a combined behavior of all the components (e.g., insulation layers, structural features) and the interactions therebetween. In examples, the structural features can have a different compressibility than the insulation layer in which and / or on which they are formed. For example, the structural features can be less compressible, more compressible or have equivalent compressibility to the insulation layer. In one example, the structural features are less compressible than a thermal barrier, such as the thermal barrier comprising an insulation layer. In other words, a thickness change in the X direction in FIG. 3 A of the thermal barrier with the structural features is less than a thicknesschange (again, in the X direction) of the thermal barrier without the structural features under compression force (e.g., force 240 in FIG. 2A). In another example, the structural features are more compressible than the thermal barrier, such as the thermal barrier comprising an insulation layer. In other words, a thickness change in the X direction in FIG. 3A of the thermal barrier with the structural features is more than a thickness change (again, in the X direction) of the thermal barrier without the structural features under compression force (e.g., force 240 in FIG. 2A).

[0060] The compressibility of the thermal barrier may be adjusted through selection of one or more aspects of the structural features, including but not limited to: material(s), feature shape(s), total surface of a collection of structural features, number and / or physical distribution on a surface of an insulation layer, individual and / or collective volume of structural features, size of the structural features, and relative position of the structural features with regard to the thermal barrier.

[0061] The structural features comprise materials selected from a non-limiting list of foam, elastomers, thermoplastics, cross-linked polymers, amorphous and / or crystalline polymers, other polymer or plastic materials, or dielectric materials. As examples, the material for the structure features may be polyimides, polycarbonates, polyester, or other appropriate materials with appropriate electrical and thermal properties. Each material has its own compressibility. The compressibility of the thermal barrier can be adjusted by choosing structural features of different materials.

[0062] The compressibility of the structural features may introduce higher heat conductivity to the insulation layer that forms the body of the thermal barrier. In other words, the thermal barrier that includes the insulation layer and the structural features may be capable of higher heat conductivity than the thermal barrier that includes the insulation layer without the structural features. The higher conductivity introduced by the structural features may be mitigated by selecting the shapes, size, and relative position of the structural features with regard to the insulation layer.

[0063] The shapes of the structural features are selected from dots, rods, tubes, spheres, hemispheres, cylinders, pyramids, lattices, nets, ribbons, frames, other appropriate shapes that provide suitable compressibility to the thermal barrier, and combinations thereof.

[0064] Different shapes of the same material may have different compressibility. Curved surfaces are more compressible than straight surfaces when subject to forces. The shapes of structural features are selected from dots, rods, tubes, spheres, hemispheres, cylinders, pyramids, lattices, nets, ribbons, frames, other appropriate shapes that provide suitable compressibility to the thermal barrier, and combinations thereof. Different shapes of the same material may have different compressibility. In one aspect, a sphere is more compressible than a cylinder made of the same material due to the curved surface of the sphere that is subject to the force. Similarly, a sphere is more compressible than a hemisphere made of the same material, because the sphere has a semicircle surface that is subject to force while the hemisphere has a quarter circle surface that is subject to force.

[0065] Different shapes of the same material provide different compression profiles for the thermal barrier during the increase of applied force. Structural features with sharper shapes (e.g., apex of a pyramid) have a smaller contact area to which force is applied and thus are easier to deform under this force, resulting in a greater thermal barrier compressibility. On the other hand, structural features with flat shapes (e.g., a cylinder-shaped structural feature with flat end surfaces) have a larger contact area to which force is applied, making them harder to deform and enabling them with smaller compressibility (harder to compress). In one aspect, the pyramid shaped structural features provide larger compressibility (easier to compress) compared to the cylindrical shaped structural features.

[0066] The number (amount) of structural features that is included affects the compressibility of the thermal barrier. In one aspect, the compressibility of the structural features is lower than the compressibility of the insulation layer(s), and thus the incorporation of the structural features into the thermal barrier decreases the compressibility of thermal barrier. The number / amount of the structural features will thus depend upon the desired level ofcompressibility. Moreover, as mentioned, the structural features impart higher thermal conductivity. Thus, the number / amount of the structural features will be determined, in part, in light of a desired thermal conductivity of the thermal barrier.

[0067] The sizes of the structural features in the thermal barrier affect the compressibility and the thermal conductivity of the thermal barrier. Larger sized structural features provide higher compressibility compared to smaller sized structural features. However, larger sized structural features also provide an undesired increased heat conduction route through the thickness of the thermal barrier. In the case where the sizes (e.g., such as the size determined by the largest dimension of the structural feature) of the structural features are greater than the thickness of the insulation layer, the heat can pass through the thickness of the thermal barrier through the structural features with higher heat conductivity. The sizes of the structural features are selected to balance the compressibility and heat conductivity of the thermal barrier. The size of the structural features may be defined by the largest dimension of the structural features. Alternatively, the size of the structural features may be defined by the dimension of the structural features along the thickness direction of the thermal barrier.

[0068] The relative positions of the structural features in the insulation layer affect the compressibility of the thermal barrier. The properties of both the structural features and the insulation layers contribute to the compressibility of the composite from the onset of the pressure if the structural features are positioned over the surface of the insulation layer. Only the structural features contribute to the compressibility from the onset of the pressure if the structural features extend through the thickness of the insulation layer.

[0069] The structural features in the insulation layer can be, in one aspect, over-molded into or onto the insulation layer. When over-molded into or onto the insulation layer, the final shape of the structural features under pressure can be flatter than the initial shape. The structural features can be inserted into and around the cavities in the insulation layer to impart shear strength and compressibility. These structural features can be, for example, created first,and then inserted there around. Alternatively, the structural features may be transferred from a carrying sheet and glued onto the insulation layers.Configurations

[0070] FIGS. 1A-1B illustrate a battery module 100 in an aspect. FIG. 1A shows one aspect of a battery module 100. The module 100 includes a stack of battery cells 102. In one aspect, the stack of cells 102 includes lithium-ion cells 102. Several configurations of lithium- ion cells 102 are possible. In one aspect, the stack of lithium-ion cells 102 includes lithium-ion pouch cells, lithium-ion prismatic cells, and / or lithium-ion cylindrical cells, although the present disclosure is not so limited. A heat sink 104 is shown located on a side of the module 100, and in thermal communication with the battery cells 102. In the aspect of FIG. 1 A, the stack of battery cells 102 are located within a module housing 106. A module cover 108 is further shown enclosing the stack of battery cells 102 within the module housing 106.

[0071] In FIG. 1 A, a thermal barrier 110 is included between each cell in the stack of battery cells 102, although the present disclosure is not so limited. In some aspects, thermal barriers 110 are shown between at least two cells in the stack of battery cells 102. In one aspect, groups of cells 102 are separated by thermal barriers 110. Inclusion of thermal barriers 110 provides a level of increased safety in the event of a thermal runaway in one or more of the cells 102. If a thermal runaway event occurs, a region affected by destruction of a failed cell 102 is contained to a region between thermal barriers 110 and / or the module housing 106. Improved thermal barriers 110 are desired to better isolate and protect adjacent regions within a battery module 100, especially in the event of thermal runaway in one or more individual cells 102.

[0072] A heat sink 104 is shown in FIG. 1A. Aspects of heat sinks 104 include, but are not limited to, passive heat sinks such as metal plates or phase change materials, and active heat sinks such as fluid recirculation systems that remove heat to a remote location. In one aspect, the heat sink 104 is integral with a bottom surface of the module housing 106.

[0073] FIG. IB shows a cross-sectional view of the battery module 100 from FIG. 1A along line A-A’. At least some of the cells 102 are separated by thermal barriers 110. A space 130 is shown above the cells 102 within the module housing 106. Each space 130 is defined between the top of the cell 102 and the interior surface of the module cover 108, and between two adjacent thermal barriers 110, or an end of the housing 106 and cover 108 and an adjacent thermal barrier 110. In the event of a thermal runaway, gasses may vent into the space 130 above a cell 102. In one aspect, cells 102 include a vent (not shown) that specifically directs gasses into the space 130. In such an event, it is desirable to contain the hot gasses, and keep them from affecting adjacent cells 102.

[0074] The battery module 100 of FIGS. 1A and IB can include thermal barriers 110 with one or more structural features integrated into the thermal barriers 110. These structural features can be integrated into the thermal barriers 110 in various configurations, as described below.

[0075] FIGS. 2A-2B depict an aspect of a battery module 200 with battery cells 210 and thermal barriers 220. The thermal barriers 220 can be single layered or multi-layered. The thermal barriers 220 can each be between two of the battery cells 210. In an aspect, the thermal barrier 220 can include an insulation layer 222 and a structural feature 224 including a plurality of elements 226 (also referred to as elements). In one aspect, the insulation layer 222 is an aerogel material, such as an inorganic aerogel material, an organic aerogel material, a monolithic aerogel material, a composite aerogel material, an aerogel material with reinforcement, and / or an aerogel composite material with fiber reinforcement. In some cases, the elements 226 can be rods, bars, dots, spheres, hemispheres, pyramids, cylinders, or other appropriate shapes as described with respect to FIGS. 3A-10C.

[0076] Here, the battery module 200 can be, in one aspect, a stack of battery cells 210 within a housing, such as housing 106. A force 240 is applied to the stack of battery cells 210 and the thermal barriers 220 during assembly of the battery module 200 along the thickness direction of the thermal barrier 220. The thermal barriers 220 are subject to force 240 fromadjacent battery cells 210. During charge and discharge of battery module 200, the battery cells 210 respectively expand and contract, which impose, respectively, increased force 240 and decreased force 240 on the thermal barriers 220. As the battery cells 210 age, the volume of the battery cells 210 expands permanently due to the irreversibility of the volume changes during change and discharge. The thermal barriers 220 are designed to accommodate the force 240 and volume changes during assembly, operation, and degradation of the battery cells 210, in addition to the thermal management functions. The compressibility of the thermal barriers 210 are fine-tuned by the structural feature 224 according to the pressure and volume changes of the battery module 200.

[0077] The thermal barriers 220 can each include a first major surface 205 extending along the largest surface of the thermal barrier 220. The thermal barrier 220 can include a second major surface 215 opposite the first major surface 205. The thermal barrier 220 can have a thickness of 225 extending between the first major surface 205 and the second major surface 215. The first major surface 205 and the second major surface 215 of one thermal barrier 220 can, in one aspect, face two different battery cells 210 in the battery module 200 (see FIG. 2A). Alternatively, the first major surface 205 and the second major surface 215 may face an internal wall of the battery module housing, such as the housing 106 in FIGS. 1A and IB.

[0078] The elements 226 of the structural feature 224 can be embedded in the thickness 225 of the thermal barrier 220. In one aspect, the structural feature 224 can be distributed within the thermal barrier 220 (e.g., within the insulation layer 222). Each of the elements 226 of the structural feature 224 can be situated within the thermal barrier 220. The elements 226 can be situated perpendicular to the first major surface 205 and / or the second major surface 215 of the thermal barrier 220. Alternatively, the elements 226 may form an angle with the first major surface 205 and / or the second major surface 215 of the thermal barrier 220. In some aspect, the angle ranges from 0 to 90 degrees.

[0079] The elements 226 of the structural feature 224 can each pass through the thickness 225 of the insulation layer 222 from one side of the thermal barrier 220 at the first major surface 205 to the other opposing side of the thermal barrier 220 at the second major surface 215. The elements 226 can each, in one aspect, have a length equal to or longer than the thickness 225 of the insulation layer 222. In some aspects, at least one of the elements 226 passes through at least one of the first major surface 205 and the second major surface 215 of the thermal barrier 220. In some aspects, the elements 226 are embedded in the thermal barrier 220, such as the insulation layer 222 of the thermal barrier 220. In such aspects, the elements 226 are disposed between the first major surface 205 and the second major surface 215. The lengths of the elements 226 may be smaller than the thickness 225 of the thermal barrier 220 accordingly.

[0080] The structural feature 224 can provide greater shear force against the adjacent battery cells 210 compared to the thermal barriers 220 without such a structural feature 224. In one aspect, where the thermal barriers 220 are laminated, the structural feature 224 can provide support to the laminated thermal barriers 220 from delamination. The structural feature 224 further modifies the compressibility of the thermal barrier 220 and thus better accommodates the pressure and volume changes of the battery cells 210 during module assembly, charge and discharge, and degradation.

[0081] FIG. 2C shows aspects of a compressibility curve of the thermal barrier 220. The solid line shows a desired curve of force versus thickness, while the dashed line shows an undesired curve of force versus thickness. The dashed curve represents the thickness versus force response (i.e., compressibility) of a first thermal barrier that is stiffer than a second thermal barrier, which exhibits a thickness versus force response corresponding to the solid curve. In one aspect, the first thermal barrier does not have a structural feature. In one aspect, the second thermal barrier has a structural feature. In other words, the compressibility of a structure (e.g., the second thermal barrier with structural feature) corresponding to the solid curve is greater than the compressibility of a structure (e.g., the first thermal barrier withoutstructural feature) corresponding to the dashed curve. In other words, the thickness changes of a thermal barrier (e.g., the first thermal barrier without structural feature) associated with the dashed curve need to be slower during the increasing of the imposed force to achieve a desired solid curve. In some aspects described herein, structural features may be added to a thermal barrier (e.g., an insulation layer of the thermal barrier) to provide a lower compressibility relative to the thermal barrier without the structural features. This decreases the thickness change (smaller slope of the solid line compared to the dashed line) of the thermal barrier in response to some regimes of applied force, as indicated in FIG. 2C.

[0082] FIGS. 3A-3C illustrate side views in X-Z plane (e.g., along line B-B’ in FIG. 2B) of a thermal barrier 320 or 321 made of an insulation layer 322 with structural features 324. In one aspect, the insulation layer 322 is an aerogel material, such as an inorganic aerogel material, an organic aerogel material, a monolithic aerogel material, a composite aerogel material, an aerogel material with reinforcement, and / or an aerogel composite material with fiber reinforcement. The structural features 324 comprises a plurality of elements of individual rods 326. Here, the structural features 324 can be distributed in the insulation layer 322 of the thermal barrier 320. The thermal barrier 320 can be single layered (e.g., FIG. 3A) or multilayered (e.g., FIG. 3B). For example, the thermal barrier 320 may include insulation layers and / or heat conductive layers.

[0083] Each of the structural features 324 can pass through at least a portion of the thickness of the thermal barrier 320. Each of the structural features 324 can have a dimension greater than the thickness of the thermal barrier 320 (e.g., FIGS. 3A and 3B).

[0084] As shown in FIG. 3 A and FIG. 3B, the structural features 324 can extend through the thickness of the thermal barrier 320, 321. In one aspect, the structural features 324 pass through a first major surface and a second major surface of the thermal barrier 320, 321. The thermal barrier 321 in FIG. 3B has multiple layers 322a, 322b, and 322c compared to the thermal barrier 320 in FIG. 3 A, which has a single layer. The single layer of FIG. 3 A may be an insulation layer 322. In the case of FIG. 3B with more than one layer, the structural features324 can be more densely situated within the thermal barrier 321 than those shown in FIG. 3 A with a single layer to prevent the delamination of the multiple layers 322a, 322b, and 322c. The individual rods 326 in FIG. 3B pin the laminated layers 322a, 322b, and 322c of the thermal barrier 321 together, therefore preventing the delamination of the thermal barrier 321. In the aspect of FIG. 3B, the structural features 324 dominate the compressibility and resilience of the thermal barrier 321 during the assembly, charge and discharge, and battery cell degradation process at first, while the multiple layers 322a, 322b, and 322c are free from the pressure 240 imposed on the battery cells 210 along the thickness direction. As the pressure 240 increases, the structural features 324 may deform, causing physical contact between the multiple layers 322a, 322b, and 322c and the adjacent battery cells 210. The multiple layers 322a, 322b, and 322c start to contribute to compressibility and resilience thereafter.

[0085] As shown in FIG. 3C, the structural features 324 can extend partially through the thermal barrier 320. The structural features 324 can be inserted on either side of the thermal barrier 320. A length of the individual structural feature 324 along the thickness direction (X direction) of the thermal barrier 320 is less than the thickness of the thermal barrier 320. In one aspect, the structural features 324 extend through a first major surface of the thermal barrier 320 but not through a second major surface. Such configuration can help prevent thermal conduction through the thickness of the thermal barrier 320 along the individual rods 326. The structural features 324 can be inserted from both sides of the thermal barrier 320 alternately along the Z direction such as to provide better compressibility, compared to the case (not shown) where the individual structural features 324 are inserted from both sides and aligned in the Z direction. In some aspects, the structural features 324 can be less compressible than the thermal barrier 320. The structural features 324 in the thermal barrier 320 can be, in one aspect, over-molded into or onto the thermal barrier 320. The structural features 324 can be, in one aspect, dots, rods, or bars. When over-molded into or onto the thermal barrier 320, the final shape of the structural features 324 under pressure can be flatter than the initial shape.

[0086] FIGS. 3D-3J illustrate side views in the X-Z plane (e.g., along line B-B’ in FIG. 2B) of a thermal barrier 320 with structural features 324. The thermal barrier 320 comprises one or more insulation layer 322. In some aspects, the thermal barrier 320 may also include a thermal conductive layer, resilient layer, and / or other suitable layers, none of which are shown in the figures for clarity and convenience of explanation. The structural features 324 comprise a plurality of elements. The plurality of elements of the structural features 324 may include different shapes. In one aspect, each element of the structural features 324 of the plurality has a spherical shape. The structural features 324 can be distributed in the insulation layer 322 of the thermal barrier 320. The thermal barrier 320 can be single layered (e.g., FIG. 3 A) or multilayered (e g., FIG. 3B).

[0087] Each of the structural features 324 can pass through at least a portion of the thickness of the thermal barrier 320. Each of the structural features 324 can have a diameter less than, equal to, or greater than the thickness of the thermal barrier 320. The structural features 324 provide adjustable compressibility and resilience to the thermal barrier 320 at different compressing stages (e.g., different compressing distance or pressure) compared to the thermal barrier 320 without the structural features 324. The compressibility and resilience of the thermal barrier 320 are adjustable through the selection and combination of size of the structural features 324 and their positions in the thermal barrier 320. In one aspect, the structural features 324 have greater modulus than the thermal barrier 320 without the structural features 324. The modulus of the structural features 324 may be greater than a combined modulus of various layers of the thermal barrier 320, including insulation layer, resilient layers, and / or conductive layers. Thus, the addition of the structural features 324 to the thermal barrier 320 (the insulation layer 322) provides the thermal barrier 320 with better compressibility and resilience.

[0088] As shown in FIG. 3D, the diameters of the individual spheres of the structural features 324 are greater than the thickness of the insulation layers 322 in this example. In one aspect, the individual spheres / balls of the structural features 324 all have the same diameter. Atleast one of the individual balls of the structural features 324 extends through the thickness of the thermal barrier 320. In other words, at least one of the individual balls of the structural features 324 passes through both a first major surface and a second major surface of the insulation layer 322, and thus the thermal barrier 320. The same diameter of the individual spheres of the structural features 324 defines the thickness of the thermal barrier 320. In one aspect, the individual spheres of the structural features 324 each have a diameter greater than the thickness (in the X-Y direction) of the thermal barrier 320, thereby passing through the entire thickness and protruding through the first major surface and the second major surface of the thermal barrier 320.

[0089] With the configuration of FIG. 3D, the structural features 324 dominate the compressibility and resilience of the thermal barrier 320 during the assembly, charge and discharge, and degradation process of the battery cells at first, while the insulation layer 322 is free from the pressure (e.g., the pressure 240 shown in FIG. 2A) imposed on the battery cells 210 along the thickness direction. As the pressure 240 increases, the structural features 324 may deform, causing physical contact between the insulation layer 322 and the adjacent battery cells (not shown). The insulation layer 322 starts to contribute compressibility and resilience thereafter.

[0090] As shown in FIG. 3E, the structural features 324 (e.g., comprising a plurality of elements - the individual spheres of the structural features 324) are the same as the structure features 324 explained with respect to FIG. 3D, except the structural features 324 in FIG. 3E extend through only a first major surface but not a second major surface of the insulation layer 322. In one aspect, the structural features 324 contact the second major surface of the insulation layer 322, but the position of the structure features 324 relative to insulation layer 322 is not so limited. In the configuration of FIG. 3E, the thermal barrier 320 is easier to manufacture, for example, in a table casting process, because one major surface of the thermal barrier 320 is flat and can be cast on a flat surface.

[0091] As shown in FIG. 3F, the structural features 324 (e.g., comprising a plurality of elements - the individual spheres of the structural features 324) are the same as the structure features 324 explained with respect to FIG. 3D, except the structural features 324 in FIG. 3F are embedded in the thermal barrier 320 (e g., in the insulation layer 320 of the thermal barrier 320). In one aspect, the structural features 324 touch at least one of the first and second major surfaces of the insulation layer 322, but do not extend beyond the first and second major surfaces. In the configuration of FIG. 3F, both the insulation layer 322 and the structural features 324 contact the adjacent battery cells (not shown), therefore both contribute to the compressibility and resilience of the thermal barrier 320 at any given imposed pressure. The compressibility and resilience provided by the configuration of FIG. 3F is greater than the compressibility and resilience provided by the configurations of FIG. 3D and FIG. 3E. In FIG. 3F, a dimension of the individual structural feature 324 along the thickness direction (X direction) of the insulation layer 322 is less than the thickness of the insulation layer 322.

[0092] As shown in FIG. 3G, the structural features 324 (e.g., comprising a plurality of elements - the individual spheres of the structural features 324) are the same as the structure features 324 explained with respect to FIG. 3D, except the structural features 324 in FIG. 3G are fully embedded in the thermal barrier 320, e.g., in the insulation layer 322. In one aspect, the individual spheres of the structural features 324 have diameters less than the thickness of the insulation layer 322. In the configuration of FIG. 3G, only the insulation layer 322 of the thermal barrier 320 contacts the adjacent battery cells. The structural features 324 are free from touching the adjacent battery cells. As such, the insulation layer 322 provides a weaker compressibility and resilience at a lower pressure. As the pressure increases during the charge and discharge or degradation process, the insulation layer 322 is pressed to a thickness that is the same as the diameter of the individual spheres of the structural features 324. The individual spheres start to contribute to the compressibility and resilience of the thermal barrier 320 thereafter, i.e., together with the insulation layer 322. The compressibility and resilience provided by the configuration of FIG. 3G is less than the compressibility and resilienceprovided by the configuration of FIG. 3D-3F before the individual spheres of the structural features 324 kick in. The compressibility and resilience provided by the configuration of FIG. 3G is greater than the compressibility and resilience provided by the configuration of FIG. 3D- 3F after the individual spheres of the structural features 324 kick in.

[0093] As shown in FIG. 3H, the structural features 324 (e.g., comprising a plurality of elements - the individual spheres of the structural features 324) are the same as the structural features 324 explained with respect to FIG. 3D, except the structural features 324 in FIG. 3H are disposed on at least one major surface of the thermal barrier 320, e.g., the insulation layer 322 of the thermal barrier 320. The structural features 324 contact only one of the major surfaces of the insulation layer 322 without extending into the thickness of the insulation layer 322. In the configuration shown in FIG. 3H, the insulation layer 322 of the thermal barrier 320 contacts the adjacent battery cell (not shown) on one side, while the structural features 324 contact the adjacent battery cell (not shown) on the opposite side. As such, both the structural features 324 and the insulation layer 322 contribute to the compressibility and resilience of the thermal barrier 320 at any given pressure imposed on the battery module (e.g., pressure 240 in FIG. 2A). Compared to the configuration in FIG. 3G, the configuration in FIG. 3H provides smooth changes of compression and resilience during the increase of the pressure imposed on the battery module, which eliminates the sudden changes in compressibility and resilience of the thermal barrier 320 when the structural features 324 kick in in the aspect of FIG. 3G.

[0094] As shown in FIG. 31, the structural features 324 (e.g., comprising a plurality of elements - the individual balls of the structural features 324) are the same as the structure features 324 explained with respect to FIG. 3H with two exceptions. First, the structural features 324 in FIG. 31 are disposed on both major surfaces of the insulation layer 322. Second, the structural features 324 at least partially extend into the thickness of the insulation layer 322. In one aspect, structural features 324 on a first major surface are not aligned with corresponding structural features 324 on the second major surface. For convenience andbrevity, this lack of alignment between the structure features 324 on the opposing major surfaces is referred to as an “offset.”

[0095] In some embodiments, the structural features 324 on the first major surface and on the second major surface are offset in two separate regular arrays in which each structural feature is a same, first distance from adjacent structure features and that, if combined, would produce a regular array with half of the first distance between adjacent structural features. In other embodiments, the offset may be that of an irregular array in which a distance between adjacent structural features is random or increases / decreases in a particular direction, but that still prevents alignment between structural features on the opposing first and second major surfaces. It will be appreciated that offset patterns can be selected based on a pattern of force exerted by battery cells on the thermal barriers.

[0096] Compared to the configuration where the structural features 324 on two major surfaces are aligned, the offset configuration enables greater compressibility at high pressure because the insulation layer 322 is more compressible than the structural features 324.Compared to the configurations of FIG. 3D-3F where the structural features 324 extend through the thickness of the insulation layer 320, the configuration in FIG. 31 has lower thermal conductivity. The lower thermal conductivity is due to the lack of heat conduction along the structural features 324 through the thickness of the thermal barrier 320. The structural features 324 has a higher thermal conductivity than the insulation layer 322.

[0097] As shown in FIG. 3 J, the thermal barrier 320 comprises an insulation layer 322 with preformed cavities 325 to accommodate the structural features 324 (e.g., comprising the individual spheres of the structural features 324). The structural features 324 are positioned into cavities 325 to form the thermal barrier 320 shown in FIG. 31. The preformed cavities 325 reduce compression of the insulation layer 322 compared to the insulation layers without the preformed cavities 325. The structural features 324 may be glued or heat pressed into the preformed cavities 325. Alternatively, the structural features 324 may be formed by drippingliquid state materials of the structural features 324 into the cavities 325 followed by a drying process.

[0098] As shown in FIG. 3K, the structural features 324 (e.g., comprising a plurality of elements - the individual cylinder 330) are the same as the structure features 324 explained with respect to FIG. 3D, except the structural features 324 in FIG. 3K are individual cylinders 330 instead of individual spheres of the structural features 324 in FIG. 3D. Individual cylinders 330 are easier to process than individual spheres since spheres require more sophisticated engineering than cylinders. In addition, compared to the individual spheres of the structural features 324, the individual cylinders 330 are less compressible and more resilient to pressure (e.g., the pressure 240 in FIG. 2A) imposed to the thermal barrier 320.

[0099] As shown in FIG. 3L, the structural features 324 (e.g., comprising a plurality of elements - the individual hemispheres 332) are the same as the structure features 324 explained with respect to FIG. 31, except the structural features 324 in FIG. 3K are individual hemispheres 332 instead of individual spheres of the structural features 324 in FIG. 31. Individual hemispheres 332 have a base 335 that is easier to be attached to the major surfaces of the insulation layer 322 without the need of preformed cavities 325, while still possessing at least portions of the compressibility and resilience of the sphere shapes.

[0100] As shown in FIG. 3M, the structural features 324 (e.g., comprising a plurality of elements - the individual hemispheres 332) are the same as the structure features 324 explained with respect to FIG. 3L, except the individual hemispheres 324 in FIG. 3M contact the insulation layer 322 at the apex 333 instead of the base 335, as shown in FIG. 3L. Compared to the configuration in FIG. 3L, the smaller contact areas at the apex 333 in FIG. 3M provide smaller compression and resilience when the pressure (e.g., pressure 240 in FIG. 2A) is first applied to the thermal barrier 320 due to the smaller contact area with the thermal barrier 320.

[0101] As shown in FIG. 3N, the structural features 324 (e.g., comprising a plurality of elements - the individual pyramids 336) are the same as the structure features 324 explained with respect to FIG. 3M, except the individual pyramids 336 in FIG. 3N replace the individualhemispheres 332 in FIG. 3M. Each pyramid 336 has a sharper apex 337 compared to the apex 333 of the hemisphere 332, and therefore is prone to deform or penetrate to the insulation layer 332 when a pressure (e.g., pressure 240 in FIG. 2A) is applied. The easier penetration results in smaller resilience when pressed.

[0102] As shown in FIG. 3N, the thermal barrier 320 may further comprise encapsulation layers 338 over at least one major surface of the insulation layer 322. The structural features 324 are disposed between the insulation layer 322 and the encapsulation layer 338. Encapsulation layer 338 prevents any inadvertent debris, loose parts, or dust from falling off the thermal barrier 320. The encapsulation layer 338 reinforces the attachment of the structural features 324 onto the insulation layer 322, especially when the structural features 324 are prone to detach, such as the pyramid attaching to the insulation layers 322 by their apexes.

[0103] In one aspect, the encapsulation layers 338 cover one or both (e.g., FIG. 3N) major surfaces of the thermal barrier 320. In one aspect, the encapsulation layers of the structural features 324 may cover the entire thermal barrier 320 (full encapsulation), including the minor surfaces perpendicular to the major surfaces. The full encapsulation is costly and complex to manufacture but provides the best encapsulation results. Encapsulating both major surfaces is much easier to manufacture than the full encapsulation, and still provides decent encapsulation results, especially when the major surfaces are much larger than the minor surfaces. Encapsulating a first major surface but not the second major surface reduces cost significantly for applications where the unencapsulated surface is secured to other surfaces, such as an interior wall of the battery module.

[0104] As shown in FIG. 30, the structural features 324 (e.g., comprising a plurality of elements - the individual pyramids 336) are the same as the structural features 324 explained with respect to FIG. 3N, except for the attachment and the size differences. First, individual pyramids 336 in FIG. 30 contact the insulation layer 322 at the bases 339 instead of at the apex 337 shown in FIG. 3N. Second, the individual pyramids 336 have various sizes (as opposed to all being the same size). In one aspect, the sizes at center region of the insulation layer 322 aregreater than the sizes in a peripheral region. The larger sizes in the center region provide greater resilience during compression than the smaller sizes in a peripheral region. Alternatively, the sizes of the structural feature 324 may be smaller in the center region and larger in the peripheral region of the thermal barrier 320. Such configurations provide the possibility to fine tune the compressibility and resilience of the thermal barrier 320 across major surfaces. In one aspect, the thermal barrier 320 a first subset of the plurality of structural features 324 is disposed on the first major surface and a second subset of the plurality structural features 324 is disposed on the second major surface. In a further example of this aspect, the first major surface comprises a peripheral portion and a center portion, and some of the first subset of the plurality of structural features 324 are located in the peripheral portion. Some other of the first subset of the plurality of structural features 324 are located in the center portion. The some of the first subset have a different shape, a different composition, or both than the some other of the first subset.

[0105] As shown in FIG. 3P, the structural features 324 (e.g., comprising a plurality of elements - the individual pyramids 336) are distributed in lines and rows in the peripheral region of the thermal barrier 320, while being distributed randomly in the center region of the thermal barrier 320. In this aspect, the distribution and size of the structural features 324 are used to achieve desired compressibility and resilience across the major surface of the insulation layer 322.

[0106] FIG. 3Q and FIG. 3R depict thermal barrier precursors 350 and 370 that comprise a carrier sheet 352 or 372 and structural features 324. The structural features 324 may be carried on the carrying sheet 352 or 372 prior to transfer to the thermal barrier 320 (e.g., the insulation layer 322 of the thermal barrier 320). The structural features 324 may be attached to the carrier sheet 352 or 372 by double-sized tape, adhesive, or other suitable methods of attaching. The carrier sheet 352 and 372 may be a plastic sheet, a fabric sheet, a net, a paper sheet, other suitable sheets, or combinations thereof. Carrier sheet 372 is a mesh sheet with wires 374 connecting the structural features 324 and voids 376 between the wires 374 and thestructural features 324. The mesh sheet (carrier sheet 372) is not only easier to apply than the sheet 352, but the mesh sheet 372 is also cost effective for using less material to carry the structural features 324. In some embodiments, the carrier sheets 352 and 372 are peeled off from the structural features 324 when they are applied to the insulation layer 322. In some embodiments, the carrier sheets 352 and 372 are applied to the insulation layer 322 together with the structural features 324 as at least a portion of the encapsulation layers. The encapsulation layers are described in detail with respect to FIG. 3N.

[0107] As shown in FIG. 3S, the insulation layer 322 comprises a reticulated network with cavities formed therein. In one aspect, the insulation layer 322 comprises a fiber reinforced aerogel composite. The reticulated network may be the fiber reinforcement of the aerogel composite, such as fiber glass.

[0108] As shown in FIG. 3T, the structural features 324 of various sizes are incorporated into the cavities of the recirculated network and settled in the cavities of similar sizes and shapes. The structural features 324 may freely fall into the cavities or be pressed into the cavities. Such method and configuration provide matches between the structural features 324 and the cavities. Structural features 324 with a wide size distribution are able to be incorporated into the thermal barrier 320 (e.g., the insulation layer 322 of the thermal barrier 320) and therefore increase the process tolerance.

[0109] FIGS. 4A-4C depict an aspect of how structural features 424 can be applied to a thermal barrier 400, such as an aerogel insulation layer 422 in a thermal barrier 400. In one aspect, in FIG. 4A, an exploded view of the thermal barrier 400 shows the aerogel 422 having various vertical (perpendicular to the longest edge of the thermal barrier 400) cavities 423 for situating the structural features 424 vertically therein. FIG. 4B depicts a view of the thermal barrier 400 with the structural features 424 situated into the cavities 423. FIG. 4C, by contrast, shows an aspect of the thermal barrier 400 with horizontal (parallel to the longest edge of the thermal barrier 400) cavities for situating the structural features 424 horizontally therein.

[0110] FIGS. 5A-5H depict aspects of thermal barriers 500 with various structural features 524. In one aspect, the thermal barriers 500 include an isolation layer 522. The thermal barriers 500 may further include a conductive layer, a resilient layer, and / or a heat capacitive layer, which are not illustrated in FIGS. 5A-5G. The structural feature 524A can be, in one aspect, a curved or squiggly ribbon that extends laterally along or within the thermal barrier 500. In one aspect, the structural feature 524A can be similar in shape to a sine wave along the surface of the thermal barrier 500. In FIG. 5B, the structural feature 524A can include multiple ribbons, such as two curved ribbons vertically aligned with each other on or facing a surface of the thermal barriers 500.

[0111] In FIGS. 5C and 5D, the structural feature 524B can be a frame shape, such as a rectangular or square frame around an edge of the thermal barrier 500 on a surface thereof. In some aspect, the frame shaped structural feature 524B is partially embedded into the thermal barrier 500. Alternatively, the frame shaped structural features 524B may be attached to the thermal barrier 500 by glue, tape, and / or other suitable adhesives. In some cases, the structural feature 524B can include multiple frames to increase the shear force and compressibility of the thermal barrier, such as the double frame shown in FIG. 5D. The multiple frames may include more than two nesting frames in some aspects. The frame shaped structural feature 524B illustrated in FIGS. 5C and 5D has a smaller outer periphery compared to the outer periphery of the thermal barrier 500. Alternatively, the outer periphery of the structural feature 524B may be equal or greater than the outer periphery of the thermal barrier 500 (e.g., the insulation layer 522 of the thermal barrier 500).

[0112] In FIG. 5E, the frame shaped structural feature 524C comprises a plurality of elements similar to the plurality of elements 532 explained with respect to FIGS. 3A-3T, except the structural features 524C are arranged into a frame shape similar to the frame shape explained in FIGS. 5C and 5D. The structural feature 524C alters the compressibility of the thermal barrier 500 to a desired profile (such as the solid line in FIG. 2C). The middle portion of the thermal barrier 500 within the frame shape is free of the plurality of elements 532 toaccommodate the volume changes of the battery cells (not shown) during charge and discharge process.

[0113] In one example, the structural features 524C are less compressible than the thermal barrier 500, such as the thermal barrier 500 of FIG. 5E comprising an insulation layer 522. In other words, a thickness change in the X direction in FIG. 5E with the structural features 524C is less than a thickness change (again, in the X direction) of the thermal barrier 500 without the structural features 524C under compression force (e g., force 240 in FIG.2A). In another example, the structural features 524C are more compressible than the thermal barrier 500, such as the thermal barrier 500 of FIG. 5E comprising an insulation layer 522. In other words, a thickness change in the X direction in FIG. 5E with the structural features is more than a thickness change (again, in the X direction) of the thermal barrier 500 without the structural features 524C under compression force (e.g., force 240 in FIG.2A). The relative compressibility of the structural features 524C and the thermal barrier 500 are designed according to the materials used such that the overall compressibility of the thermal barrier 500 moves away from the dashed curve and moves toward the solid curve in FIG. 2C.

[0114] In FIG. 5F, the thermal barrier 500 includes only a frame shaped structural feature 524D without other layers, such as an insolation layer, a conductive layer, or a compressive layer. The frame shaped structural feature 524D is disposed between two battery cells 510 to accommodate the battery volume change during charge and discharge. The outer periphery of the structural feature 524D is the same size as the outer periphery of the adjacent battery cells 510. This configuration is convenient to align with the adjacent battery cells 510 during assembly. Alternatively, the outer periphery of the structural feature 524D may be smaller than the outer periphery of the adjacent battery cells 510. Such configuration accommodates the battery volume change at a position having a greater battery volume change than that of the outer periphery of the battery cells 510. In one aspect, the structural feature 524D may include a glue layer attached to the adjacent battery cells 510 to avoid misalignment.

[0115] In FIG. 5G, the thermal barrier 500 further comprises an insulation layer 522 in alignment with the frame shaped structural feature 524D. The frame shaped structural feature 524D is similar to the structural feature 524B illustrated in FIGS. 5C and 5D, except the structural feature 524D illustrated in FIG. 5G has the same size as the insulation layer 522. In other words, the outer periphery of the structural feature 524D is the same size as the outer periphery of the insulation layer 522. In this configuration, the insulation layer 522 provides heat insulation property, while the structural feature 524D alters compressibility and additional spaces within the frame for battery volume expansion.

[0116] In FIG. 5H, the thermal barrier 500 comprises an insulation layer 522 and a frame shaped structural feature 524E around the insulation layer 522. The insulation layer 522 and the structural feature 524E may be coplanar with each other. In one aspect, a thickness of the insulation layer 522 is smaller than a thickness of structural feature 524E, such that the insulation layer 522 does not contact the major surfaces of the adjacent battery cells (not shown) initially. The insulation layer 522 may contact the major surfaces of the adjacent battery cells when the volume of the battery cells expanded during charge, discharge, and / or aging. The thermal barrier 500 may further comprise encapsulation layers 526 on at least one major surface. In one aspect, the encapsulation layer 526 may cover the major surfaces of both the insulation layer 522 and the structural feature 524E. In one aspect, the encapsulation layer 526 may wrap around the entire thermal barrier 500, including the insulation layer 522 and the frame shaped structural feature 524E. In one aspect, the encapsulation layer 526 may wrap around the entire insulation layer 522 but not the structural feature 524E.

[0117] In one example, the structural features 524D or 524E are less compressible than the thermal barrier 500, such as the thermal barrier 500 of FIGS. 5F-5H comprising an insulation layer 522. In other words, a thickness change in the X direction in FIGS. 5F-5H with the structural features 524D and 524E is less than a thickness change (again, in the X direction) of the thermal barrier 500 without the structural features 524D and 524E under compression force (e.g., force 240 in FIG.2A). In another example, the structural features 524D and 524Eare more compressible than the thermal barrier 500, such as the thermal barrier 500 of FIGS. 5E-5H comprising an insulation layer 522. In other words, a thickness change in the X direction in FIGS. 5F-5H with the structural features 524D and 524E is more than a thickness change (again, in the X direction) of the thermal barrier 500 without the structural features 524D and 524E under compression force (e.g., force 240 in FIG.2A). The relative compressibility of the structural features 524D and 524E and the thermal barrier 500 are designed according to the materials used such that the overall compressibility of the thermal barrier 500 moves away from the dashed curve and moves toward the solid curve in FIG. 2C.

[0118] FIGS. 6A-6C illustrate various views of a thermal barrier 600 with curved ribbon structural features 624 extending through a thickness of the thermal barrier 600. As shown in FIGS. 6A and 6B, the curved ribbon structural features may be nonparallel to the surfaces of the thermal barrier 600. In one aspect, the curved ribbon structure features can form a 45° angle with the major surface of the thermal barrier 600, as shown in FIGS. 6A and 6B. Here, the various structural features 624 can include a zig-zag in the X-Z plane that goes along a thickness of the thermal barrier 600. In some aspects, the various structural feature 624 can form an acute (e.g., 45°) or obtuse angle (e.g., 135°) with the largest surface of the thermal barrier 600. In some cases, the various structural feature 624 can form an acute (e.g., 45°) or obtuse angle (e.g., 135°) with a smaller surface of the thermal barrier 600. The structural feature 624 can be similar in shape to a sine wave between a first major surface 605 and a second major surface 615 of the thermal barrier 600.

[0119] As shown in a top view shown in FIG. 6C, the curved ribbon structural feature 624 has a zig-zag shape in the Y-Z plane. The curved ribbon structural features 624 can form an angle with the edges 626 and 628 of the thermal barrier 600 in the Y-Z plane.

[0120] In some cases, the various structural features 624 can have a thickness similar to that of the thermal barrier 600. In some cases, where the structural feature 624 is a curved ribbon, the various structural features 624 can curve such that the peaks 625 of the curved ribbon are adjacent and / or extend just past the first and the second major surfaces 605 and 615of the thermal barrier 600. This is shown in FIG. 6B. The peaks 625 of the curved ribbon extend just past the surfaces 605 and 615 provide additional shear force to prevent the disposition of the thermal barrier 600 relative to the position of the adjacent battery cells. The various structural features 624 can provide better compressibility along the thickness direction of the thermal barrier 600.

[0121] FIGS. 7A-7C illustrate various views of a thermal barrier 700 with flexible fiber structural features 724. In this aspect, the flexible fiber structural features 724 can be made of fibers that are stitched through the aerogel 722 of the thermal barrier 700. A portion of the flexible fiber structural features 724 can be situated on the surface (a first and / or a second major surface) of the thermal barrier 700. The flexible fiber structural features 724 can provide shear force with respect to adjacent cells (not shown) and can prevent the thermal barrier 700 from sliding with respect to those cells. In some cases, the flexible fiber structural features 724 can be stitched vertically relative to a major surface 705 of the thermal barrier 700. In some cases, the flexible fiber structural features 724 can be stitched horizontally (e.g., parallel to) relative to a major surface 705 of the thermal barrier 700. In some cases, the flexible fiber structural features 724 can be diagonal to the major surface 705 of the thermal barrier 700. FIG. 7B shows a cross-sectional view (X-Z plane) of the structural features 724 stitched through laminated thermal barrier 700. The laminated thermal barrier 700 may include an isolation layer, a heat conductive layer, a resistant layer, etc. The structural features 724 prevent the laminated thermal barrier 700 from delamination. FIG.7C shows each stitch forming an isolated island on the major surface 705 of the thermal barrier 700.

[0122] FIGS. 8A-8B illustrate various views of a thermal barrier 800 with heat pressed structural features 824. In this case, a plurality of elements 826 can make up a single structural feature 824, such as by having the element pressed together to form a web or sheet. The web or sheet is different from the isolated islands illustrated in FIG. 7C in that the web or sheet covers a greater percentage of the major surfaces of the thermal barrier 800. In some cases, a surface portion of the structural feature 824 can extend beyond the surface of the thermal barrier 800.In some cases, a portion of the structural feature 824 can remain unaffected by heat pressing, such as the portions within the thickness of the thermal barrier 800.

[0123] FIGS. 9A-9B illustrate a cross-sectional view and a top view of a thermal barrier 900 with a structural feature 924. A portion of the structural feature 924 can be pressed into a connection layer. In one aspect, the portion of the structural feature 924 on first and second major surfaces 905 and 915 of the thermal barrier 900 are pressed to form a connection layer. The connection layer is different from the web or sheet illustrated in FIG. 8B in that the connection layer covers a higher percentage of the major surfaces of the thermal barrier. In one aspect, the connection layer covers the entire first major surface 905 and / or the entire second major surface 915. The connection layer encapsulates the thermal barrier 900 and prevents dust generated from the thermal barrier 900. The connection layer can also increase shear force between the thermal barrier 900 and an adjacent battery cell.

[0124] FIGS. 10A-10C illustrate views of a thermal barrier 1000 having a structure feature 1024. In this aspect, the structure feature 1024 can have edges 1025 that are thinner relative to a center of the structure feature 1024. This can allow, in one aspect, for additional space in and around the edges of the thermal barrier 1000 where desired, such as near a tab area of an adjacent battery cell. The thermal barrier 1000 may have one or more thinner edges 1025. In one aspect, the thermal barrier 1000 may have two thinner edges on the opposite sides of the thermal barrier 1000. Alternatively, all four edges of the thermal barrier 1000 may be thinner edges. The thinner edges can be formed by pressing, such as heat pressing. The heat pressed portion of structure feature 1024 at the thinner edges can help maintain the thinner thickness from springing back to the original thickness.

[0125] FIG. 11 illustrates a flow chart of a method of making a thermal barrier with a structural feature. In one aspect, the method 1100 can include removing a portion of aerogel in the thermal barrier to form one or more cavities (block 1110) and forming a structural feature in the one or more cavities (block 1120).

[0126] In some cases, the structural feature can be formed by injecting an appropriate material, such as polyimide, polycarbonate, polyester, or combinations thereof. In some cases, an over-mold technique can be used. In some cases, the structural feature material can be partially embedded in the thermal barrier. In some cases, the structural feature material can be embedded into the thermal barrier such that it extends therethrough. In some cases, the method can further include heat pressing a portion of the structural feature material.Various Notes & Aspects

[0127] Aspect 1 is a thermal barrier comprising an insulation layer having a first major surface, a second major surface on a side opposing the first major surface, and a thickness extending between the first major surface and the second major surface, wherein the insulation layer has a first compressibility; and a structural feature in contact with the insulation layer, the structural feature having a second compressibility less than the first compressibility.

[0128] Aspect 1.5 is a battery module comprising: a stack of battery cells located within a module housing; a thermal barrier between at least two cells in the stack of battery cells, the thermal barrier having a first major surface, a second major surface on a side opposing the first major surface, and a thickness extending between the first major surface and the second major surface; and a structural feature distributed over the thermal barrier, the structural feature comprising a plurality of elements, and the plurality of elements decreases the compressibility of the thermal barrier.

[0129] In Aspect 2, the subject matter of Aspect 1 wherein the structural feature is disposed on the first major surface.

[0130] In Aspect 3, the subject matter of any one or more of Aspect 1 wherein the structural feature comprises a plurality of structural features, and wherein a first subset of the plurality is disposed on the first major surface and a second subset of the plurality is disposed on the second major surface.

[0131] In Aspect 4, the subject matter of Aspect 3 wherein the first subset of the plurality of structural features disposed on the first major surface is offset from the second subset of the plurality of structural features disposed on the second major surface.

[0132] In Aspect 5, the subject matter of Aspect 1 wherein the structural feature extends at least partially through the first major surface into the thickness of the thermal barrier.

[0133] In Aspect 6, the subject matter of Aspect 5 wherein the structural feature contacts the second major surface.

[0134] In Aspect 7, the subject matter of Aspect 5 wherein the structural feature extends through the first major surface, the thickness, and the second major surface.

[0135] In Aspect 8, the subject matter of Aspect 1 wherein the structural feature is embedded in the thickness of the thermal barrier between the first and the second major surfaces.

[0136] In Aspect 9, the subject matter of Aspect 1 wherein the structural feature comprises a hemisphere, and wherein the hemisphere has an apex contacting the first major surface and a circular base opposite the first major surface.

[0137] In Aspect 10, the subject matter of Aspect 3 wherein the plurality of structural features comprises one or more of cylinders, spheres, hemispheres, pyramids, rods, bars, dots, and irregular geometrical shape.

[0138] In Aspect 11, the subject matter of Aspect 3 wherein the plurality of structural features comprises a range of sizes.

[0139] In Aspect 12, the subject matter of Aspect 3 wherein the plurality of structural features is disposed on a carrying sheet.

[0140] In Aspect 13, the subject matter of Aspect 12 wherein the carrying sheet forms at least a portion of an encapsulation layer.

[0141] In Aspect 14, the subject matter of Aspect 13 wherein the carrying sheet is a net.

[0142] In Aspect 15, the subject matter of Aspect 3 wherein: the first major surface comprises a peripheral portion and a center portion; some of the first subset of the plurality ofstructural features are located in the peripheral portion; some other of the first subset of the plurality of structural features are located in the center portion; and the some of the first subset have a different shape, a different composition, or both than the some other of the first subset.

[0143] In Aspect 16, the subject matter of Aspect 3 wherein at least one of the first major surface and the second major surface include pre-formed cavities for disposing corresponding ones of the plurality of structural features therein.

[0144] In Aspect 17, the subject matter of Aspect 3 wherein the thermal barrier comprises a reticulated network having irregular pores housing at least a portion of the plurality of structural features m.

[0145] In Aspect 18, the subject matter of Aspect 3 wherein the plurality of structural features comprises at least one of a polymer, rubber, resin, and foam.

[0146] In Aspect 19, the subject matter of Aspect 19 wherein the structural feature has a frame shape.

[0147] In Aspect 20, the subject matter of Aspect 1 wherein the structural feature has a rectangular frame with an outer periphery a same size as that of an outer periphery of the insulation layer.

[0148] In Aspect 21, the subject matter of Aspect 1, wherein the structural feature has a rectangular frame with an outer periphery smaller than that of an outer periphery of the insulation layer.

[0149] Aspect 22 is a method of making a thermal barrier, comprising removing a portion of the thermal barrier to form one or more cavities; and forming an individual structural feature in a corresponding of the one or more cavities.

[0150] In Aspect 23, the method of Aspect 22 wherein the forming of the individual structural feature comprises injecting a structural material into the corresponding one of the one or more cavities.

[0151] In Aspect 24, the method of Aspect 22 wherein the forming of the individual structural feature comprises over-molding or heat pressing a structural material onto the thermal barrier.

[0152] In Aspect 25, the method of Aspect 22 wherein the forming of the individual structural feature comprises transferring a plurality of structural features from a carrying sheet to a first major surface aligned with the one or more cavities.

[0153] Each of these non-limiting aspects can stand on its own or can be combined in various permutations or combinations with one or more of the other aspects.

[0154] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “aspects.” Such aspects can include elements in addition to those shown or described. However, the present inventors also contemplate aspects in which only those elements shown or described are provided. Moreover, the present inventors also contemplate aspects using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular aspect (or one or more aspects thereof), or with respect to other aspects (or one or more aspects thereof) shown or described herein.

[0155] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.

[0156] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in thefollowing claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0157] The above description is intended to be illustrative, and not restrictive. In one aspect, the above-described aspects (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as aspects or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

What is claimed is:

1. A thermal barrier, comprising: an insulation layer having a first major surface, a second major surface on a side opposing the first major surface, and a thickness defined by a distance between the first major surface and the second major surface, wherein the insulation layer has a first compressibility; and a structural feature in contact with the insulation layer, the structural feature having a second compressibility less than the first compressibility.

2. The thermal barrier of claim 1, wherein the structural feature is disposed on the first major surface.

3. The thermal barrier of claim 1, wherein the structural feature comprises a plurality of structural features, and wherein a first subset of the plurality is disposed on the first major surface and a second subset of the plurality is disposed on the second major surface.

4. The thermal barrier of claim 3, wherein the first subset of the plurality of structural features disposed on the first major surface is offset from the second subset of the plurality of structural features disposed on the second major surface.

5. The thermal barrier of claim 1, wherein the structural feature extends at least partially through the first major surface into the thickness of the thermal barrier.

6. The thermal barrier of claim 5, wherein the structural feature contacts the second major surface.

7. The thermal barrier of claim 5, wherein the structural feature extends through the first major surface, the thickness, and the second major surface.

8. The thermal barrier of claim 1, wherein the structural feature is embedded in the thickness of the thermal barrier between the first and the second major surfaces.

9. The thermal barrier of claim 1, wherein the structural feature comprises a hemisphere, and wherein the hemisphere has an apex contacting the first major surface and a circular base opposite the first major surface.

10. The thermal barrier of claim 3, wherein the plurality of structural features comprises one or more of cylinders, spheres, hemispheres, pyramids, rods, bars, dots, and irregular geometrical shapes.

11. The thermal barrier of claim 3, wherein the plurality of structural features comprises a range of sizes.

12. The thermal barrier of claim 3, wherein the plurality of structural features is disposed on a carrying sheet.

13. The thermal barrier of claim 12, wherein the carrying sheet forms at least a portion of an encapsulation layer.

14. The thermal barrier of claim 13, wherein the carrying sheet is a net.

15. The thermal barrier of claim 3, wherein: the first major surface comprises a peripheral portion and a center portion; some of the first subset of the plurality of structural features are located in the peripheral portion; some other of the first subset of the plurality of structural features are located in the center portion; andthe some of the first subset have a different shape, a different composition, or both than the some other of the first subset.

16. The thermal barrier of claim 3, wherein at least one of the first major surface and the second major surface include pre-formed cavities for disposing corresponding ones of the plurality of structural features therein.

17. The thermal barrier of claim 3, wherein the thermal barrier comprises a reticulated network having irregular pores housing at least a portion of the plurality of structural features.

18. The thermal barrier of claim 3, wherein the plurality of structural features comprises at least one of a polymer, rubber, resin, and foam.

19. The thermal barrier of claim 1, wherein the structural feature has a frame shape.

20. The thermal barrier of claim 1, wherein the structural feature has a rectangular frame with an outer periphery a same size as that of an outer periphery of the insulation layer.

21. The thermal barrier of claim 1, wherein the structural feature has a rectangular frame with an outer periphery smaller than that of an outer periphery of the insulation layer.

22. A method of making a thermal barrier, comprising: removing a portion of the thermal barrier to form one or more cavities; and forming an individual structural feature in a corresponding of the one or more cavities.

23. The method of claim 22, wherein the forming of the individual structural feature comprises injecting a structural material into the corresponding one of the one or more cavities.

24. The method of claim 22, wherein the forming of the individual structural feature comprises over-molding or heat pressing a structural material onto the thermal barrier.

25. The method of claim 22, wherein the forming of the individual structural feature comprises transferring a plurality of structural features from a carrying sheet to a first major surface aligned with the one or more cavities.

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