Proportional thermal barrier device

Abstract

A battery module (100) includes a plurality of battery cells (102). The battery cells define a heat transfer surface defining a cross-section area. The battery module includes one or more thermal barriers (110) dividing the plurality of battery cells into cell subdivisions (112, 114), each of the cell subdivisions having a cell subdivision energy storage capacity. The thermal barriers are formed from a volume of thermal insulation material. An areal energy density is equal to one half of the cell subdivision energy storage capacity divided by the cross section area. The volume of thermal insulation material divided by one half of the cell subdivision energy storage capacity defines a proportion.

Description

AAI-107-A-PCT (1189-WO01) 1 PROPORTIONAL THERMAL DEVICE AND METHOD Cross-Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application Serial Number 63 / 531,793, filed August 9, 2023, the content 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 preventing or 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 that includes the thermal barrier materials, as well as systems including those battery modules or packs. Examples described generally may include aerogel materials. Background

[0003] Lithium-ion batteries (LIBs) are used in powering some electronic devices such as cell phones, tablets, laptops, power tools and other high-current devices including electric vehicles because LIBs have a high working voltage, low memory effects, and high energy density compared to traditional batteries. Lithium-ion batteries (LIBs) are used in powering some electronic devices such as cell phones, tablets, laptops, power tools and other high-current devices including electric vehicles because LIBs have a high working voltage, low memory effects, and high energy density compared to traditional batteries. Some LIBs may be susceptible to certain failure modes under conditions that are beyond the normal working conditions, such as when a rechargeable battery is overcharged (beyond the design voltage), over-discharged, operated at or exposed to temperatures and pressures outside of the design parameter space.

[0004] To prevent 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.AAI-107-A-PCT (1189-WO01) 2 Brief of the Drawings

[0005] FIG.1A is a semi-schematic perspective view depicting a battery module in accordance with some aspects;

[0006] FIG.1B is a semi-schematic front view depicting another battery module in accordance with some aspects;

[0007] FIG.2A is a schematic perspective view depicting components of a battery module in accordance with some aspects;

[0008] FIG.2B is a cross-sectional view taken through a vertical plane of the thermal barrier depicted in FIG.2A, with a thermal gradient superimposed on the cross- sectional view;

[0009] FIG.2C is a graph of battery module data in accordance with some aspects;

[0010] FIG.2D is a side view of the components of the battery module depicted in FIG.2A;

[0011] FIG.3 is a semi-schematic exploded perspective view of another battery module in accordance with some aspects;

[0012] FIG.4 is a semi-schematic partially exploded perspective view of another battery module in accordance with some aspects;

[0013] FIG.5 is a semi-schematic partially exploded perspective view of another battery module in accordance with some aspects;

[0014] FIG.6 is a semi-schematic partially exploded perspective view of another battery module in accordance with some aspects;

[0015] FIG.7A is a semi-schematic partially exploded perspective view of a battery pack in accordance with some aspects;

[0016] FIG.7B is a side view of the assembled battery pack depicted in FIG 7A with portions of the housing and lid removed;

[0017] FIG.8 is a semi-schematic partially exploded perspective view of another battery pack in accordance with some aspects;

[0018] FIG.9 is a semi-schematic partially exploded perspective view of another battery pack in accordance with some aspects;

[0019] FIG.10 is a semi-schematic top view of an electronic device in accordance with some aspects; and

[0020] FIG.11 is a semi-schematic top view of an electric vehicle in accordance with some aspects.AAI-107-A-PCT (1189-WO01) 3 Description of Embodiments

[0021] 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.

[0022] The present disclosure is directed to an energy storage system including multiple battery cells and one or more thermal barriers disposed therebetween. The energy storage system is defined by a ratio of a thickness of the thermal barriers to the battery cell areal energy density. The energy storage system may also be defined by a ratio of a volume of the thermal barrier to the energy stored in the energy storage system. The ratios are designed to delay or prevent extreme thermal events, such as overheating or thermal runaway.

[0023] The thermal barriers may include insulation materials, thermal conductor materials, resilient materials, etc. as described in examples below, can be used in battery modules to compartmentalize individual battery cells, or groups of battery cells in a battery device. Multiple battery cells that are coupled together are referred to in the present disclosure as battery modules. However, devices and methods described can be used in any of several types of multiple cell arrangements, that may be termed battery packs, battery systems, etc.

[0024] Insulation materials as described below can be used as a single heat resistant layer, or in combination with other layers (e.g., conductive layers and / or resilient layers) that provide additional function to a multilayer configuration, such as mechanical strength, compressibility, heat dissipation / conduction, etc. The heat resistant layer may be resistant to damage from high temperatures, and / or the heat resistant layer may resist the transfer of thermal energy through the heat resistant layer by having a low coefficient of heat transfer. Insulation layers described herein are responsible for reliably containing and controlling heat flow from heat-generating parts in small spaces and to prevent or resist fire propagation for such products in the fields of electronic, industrial and automotive technologies.

[0025] In many aspects of the present disclosure, the insulation layer functions as a heat / 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 insulationAAI-107-A-PCT (1189-WO01) 4 layer may itself be resistant to heat, flame hot gases and further include entrained particulate materials that modify or enhance heat containment and control.

[0026] One aspect of 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 (e.g., 900 m2 / g or higher) and nanometer scale pore sizes. The pores may be filled 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 invention is not so limited. Other thermal insulation material layers may also be used in aspects of the present disclosure.

[0027] 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. In one aspect, the solvent is extracted by supercritical drying. During the supercritical drying process, the insulation material (e.g., aerogel) is placed under suitable pressure and temperature to reach the supercritical condition of the solvent. Under supercritical conditions, the solvent can be extracted without damaging the porous matrix due to the reduced surface tension and capillary stress.

[0028] A variety of different aerogel compositions are known, and they may be inorganic, organic and 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.

[0029] 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 / orAAI-107-A-PCT (1189-WO01) 5 condensed polymers of tetra-n- polyethylsilicates, partially hydrolyzed polyethysilicates, monomeric alkylalkoxy silanes, bis-trialkoxy alkyl or aryl silanes, polyhedral silsesquioxanes, or combinations thereof.

[0030] In certain aspects 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.

[0031] 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 diethoxysilane (DMDS), methyl triethoxysilane (MTES), ethyl triethoxysilane (ETES), diethyl diethoxysilane, dimethyl diethoxysilane (DMDES), ethyl triethoxysilane, 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 of other chemical groups may be added or cross-linked to one or more of the above precursors.

[0032] 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,AAI-107-A-PCT (1189-WO01) 6 agarose, chitosan, and combinations As one aspect, organic RF aerogels are typically made from the sol-gel polymerization of resorcinol or melamine with formaldehyde under alkaline conditions.

[0033] 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(OX)4. In these formulas, X may represent, for example, CH3, C2H5, C3H7, C4H9; Y may represent, for example, 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.

[0034] Aerogels can be formed from flexible gel precursors. Various flexible layers, including flexible fiber-reinforced aerogels, can be readily combined and shaped to give pre-forms that when mechanically compressed along one or more axes, give compressively strong bodies along any of those axes.

[0035] 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 and low cost (alcogel). Organic aerogels can also be made from melamine formaldehydes, resorcinol formaldehydes, and the like.

[0036] 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 or carrier. 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 or carrier. 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.AAI-107-A-PCT (1189-WO01) 7

[0037] As noted above, an aerogel 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. The reinforcing material may be any material that provides resilience, conformability, or structural stability to the aerogel material. The composite of the aerogel and the reinforcing material may contain from 25 to 95% by weight of aerogel and from 5 to 75% by weight of the reinforcing 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.

[0038] The reinforcement material can be selected from, but is not limited to, 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, pre-oxidized fibers, pre-oxidized polyacrylonitrile, foam, rubber, resin, polymer, or combination thereof. In some aspects, the fibers are in the form of discrete fibers, woven materials, dry laid non-woven materials, wet laid non-woven materials, air-laid nonwovens, needled nonwovens, battings, webs, mats, felts, and / or combinations thereof. In some aspects, the reinforcement material can include a reinforcement including a plurality of layers of material. Thermal conductive layers

[0039] In addition to thermal insulating layers, the isolation material layer may further comprise thermal conductor material layers. The thermally conductive material layers in combination with thermal insulating layers are effective at channeling unwanted heat to a desired external location. Thermal communication between the thermally conductive layer and heat sink elements within the battery system allows the removal of excess heat from the battery cell or cells adjacent to the isolation material layer to the heat sink. The removal of the excess heat reduces the effect, severity, or propagation of a thermal event that may generate excessive heat. In addition to removal of heat, a thermally conductive layer can spread, or dissipate heat from a region of high heat concentration to a larger region of lower heat concentration, thereby reducing the possibility of local overheatAAI-107-A-PCT (1189-WO01) 8 and consequent thermal runaway. In one a thermally conductive layer or layers helps to dissipate heat away from a localized heat load within a battery module or pack.

[0040] High thermal conductivity materials include carbon fiber, graphite, silicon carbide, metals including but not limited to copper, stainless steel, aluminum, and the like, as well as combinations thereof.

[0041] To further distribute or remove the undesired heat, the thermal conductive layer is coupled to external heat dissipating fins, a heat dissipating housing, or other external structure to dissipate unwanted heat to outside ambient air. In at least one aspect the thermally conductive layer is 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 / 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. In another aspect, at least one thermally conductive layer 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 multilayer materials disposed between battery cells. Resilient material layers

[0042] In addition to thermal insulating layers and thermal conductive layers, the isolation material layer may further comprise one or more resilient material layers. In one aspect, a resilient layer absorbs any volume expansion during the regular operation of one or more battery cells. For example, during a charge, the cells may expand, and during a discharge, the cells may shrink. In one aspect, the resilient layer may also absorb permanent volume expansion caused by any battery cell aging, degradation, and / or thermal runaway. Resilient material layers may include, but are not limited to, foam, fiber, fabric, sponge, spring structures, rubber, polymer, resin, etc.

[0043] Fig.1A shows one example of a battery module 100. The module 100 includes a stack of battery cells 102. In one example, the stack of battery cells 102 includes lithium-ion battery cells 102, although other cell types are within the scope of the present disclosure. Several configurations of lithium-ion battery cells 102 are possible. In oneAAI-107-A-PCT (1189-WO01) 9 example, the stack of lithium-ion battery 102 includes lithium ion prismatic battery cells, lithium ion pouch battery cells, or lithium ion cylindrical battery cells, although the invention is not so limited. In one example, the stack of lithium-ion battery cells 102 includes lithium nickel manganese cobalt (NMC) oxide battery cells and or lithium iron phosphate (LFP) battery cells, although the invention is not so limited. The number of battery cells 102 are grouped into a number of cell subdivisions 112, 114. As noted above, it is desirable to stop or mitigate thermal runaway conditions that can occur in battery cells such as lithium-ion battery cells 102. A thermal barrier 110 is shown located between adjacent cell subdivisions 112, 114 to stop or mitigate thermal runaway between cell subdivisions 112, 114.

[0044] The battery cells 102 in Fig.1A each include electrical terminals 104. Although battery cells 102 with terminals 104 on a top surface of the battery cells 102 are shown in the example of Fig.1A, other configurations are also within the scope of the invention, including, but not limited to other examples illustrated in Figs. below.

[0045] Fig.1B shows an optional configuration of a battery module 150 that includes a heat sink 154 located on a side of the module 150, and in thermal communication with the battery cells 152. Fig.1B shows a cross section of battery module 150. One or more of the battery cells 152 are shown separated by one or more thermal barriers 160. Although in Fig.1B, only selected groups, or subdivisions, of battery cells 152 are separated by thermal barrier 160, the present disclosure is not so limited. In other examples, every cell 152 is bounded by thermal barriers 160. Side, bottom or top surfaces of the battery module 150 may also include thermal barriers 160. Examples of thermal barriers 110, 160 are shown in more detail in discussion of Figs. below.

[0046] Fig.2A shows a diagram of a first thermal barrier 214 separating a first cell subdivision 210 and a second cell subdivision 212. A second thermal barrier 214’ is adjacent to the second cell subdivision 212 distal to the first thermal barrier 214. The first thermal barrier 214 and the second thermal barrier 214’ each have dimensions including a height 202, a width 204, and a thickness 206. A cross section area is defined as the height 202 multiplied by the width 204. A volume of the first thermal barrier 214 and the second thermal barrier 214’ is defined as the height 202 multiplied by the width 204, multiplied by the thickness 206.AAI-107-A-PCT (1189-WO01) 10

[0047] The first thermal barrier 214 a first interface 215 with the first cell subdivision 210 and a second interface 217 with the second cell subdivision 212. The subdivisions 210 and 212 each have a height 202 and a width 204.

[0048] Fig.2B is a cross-sectional view taken through a vertical plane of the thermal barrier 214 depicted in FIG.2A, with a thermal gradient 219 superimposed on the cross-sectional view 2B. The thermal gradient 219 in view of the arrow depicting heat 221 shows that at the heat flows from hot to cold. As used herein, heat into a system is considered to have a positive direction.

[0049] As used herein, the term “heat” means thermal energy, or a transfer of thermal energy depending on the context. Further, in some cases, the term “heat” can refer to “high temperature.”

[0050] "Fourier's Law" may be expressed as q = (k / s) A dT, wherein: q = heat transfer (Watt (W), Joule / second (J / s)); k = Thermal Conductivity of material (Watt / meter Kelvin, W / m ºC); s = material thickness (m); A = heat transfer area (m2); dT = t1 - t2 = temperature gradient (difference) over the material (ºC). U = k / s, the Coefficient of Heat Transfer (W / (m2K))

[0051] As shown by Fourier’s Law, over a given period of time, the temperature drop across a thermal barrier depends on the rate of energy transferred and the heat transfer area. As disclosed herein, the heat transfer (q) out of a cell subdivision is bounded by the amount of energy stored in the cell subdivision. In other words, if all of the energy stored in a cell subdivision is released over a given time period, the system will have the potential for the highest q. It can also be shown by Fourier’s Law that the rate of heat transfer is proportional to the heat transfer area.

[0052] In the present disclosure, the term “areal energy density” means the energy in a cell subdivision (or other body of interest) divided by the heat transfer area. In some aspects, the temperature and heat transfer potential may be considered as symmetrical on both sides of the cell subdivision. Thus, in some aspects, the areal energy density may be calculated by dividing the energy stored in the cell subdivision by the total area on both sides of the cell subdivision. In a case where cooling channels are used to remove heat from cell subdivision 210, the energy removed by the cooling channel is subtracted from the energy stored when calculating the areal energy density. This total energy (energy stored – energy removed) that is potentially available to be transferred is divided by an area through which the thermal energy may be transferred, i.e., the surface area of the cell subdivision.AAI-107-A-PCT (1189-WO01) 11 For convenience, in the calculations of the disclosure, it is assumed that errors introduced by assuming that thermal energy is only available for transfer through the two largest opposed surfaces of a prismatic battery cell are negligible. The surface area of the cell subdivision (e.g., cell subdivision 212, which is equal to an area of the second interface 217 (height 202 multiplied by width 204) added to an area of a third interface 213 (also height 202 multiplied by width 204). In the example shown in Fig.2B, the area of the second interface 217 is equal to the area of the third interface 213, thus the surface area of the cell subdivision (e.g., second cell subdivision 212) can be described as 2 times an interface area. In the example shown, the second interface 217 and the third interface 213 depict insulated heat transfer surfaces of the cell subdivision.

[0053] Fig.2C shows a graph 250 relating cell areal energy density as defined above to the thickness of the thermal barrier 214. As used herein, the term “X-axis” refers to the horizontal axis of a two-dimensional graph. As used herein, the term “Y-axis” refers to the vertical axis of a two-dimensional graph. In Fig.2C, the X-axis 256 indicates a cell areal energy density in kwh / m2. As disclosed herein, the cell areal energy density is defined as an amount of energy stored (E) in a cell subdivision divided by a surface area of a thermal barrier in contact with the cell subdivision (e.g., twice a cross section area, or area of a face (Aface)). As shown in Figure 2A, twice a cross section area is equal to the second interface 217 plus the third interface 213.

[0054] A first Y-axis 252 indicates an uncompressed thickness of a thermal barrier in millimeters, such as thermal barrier 214 from Figure 2A, or thermal barrier 110, 160 from Figs.1A and 1B (respectively). A second Y-axis 254 indicates a compressed thickness of a thermal barrier in millimeters, such as thermal barrier 214 from Figure 2A, or thermal barrier 110, 160 from Figs.1A and 1B (respectively). In an aspect, the compressed thickness may be in a range between about 10% and about 100% of the uncompressed thickness. In one aspect, the compressed thickness is greater than about 90%, greater than about 70%, greater than about 50%, greater than about 30%, or greater than about 10% of the uncompressed thickness. In one example a compressed thickness is greater than 50% of the uncompressed thickness.

[0055] In examples where the thermal barrier (214, 214’, 110, 160) includes an aerogel, thermal conductivity may be substantially unaffected by compression. It is to be understood that “thermal conductivity may be substantially unaffected by compression” means the thermal conductivity in a compressed state may be within 10 percent of theAAI-107-A-PCT (1189-WO01) 12 thermal conductivity in the uncompressed In some aspects, the thermal barrier after compression exhibits a lower thermal conductivity compared to the thermal conductivity before compression. In one aspect, the thermal conductivity after compression is about 20% lower than the thermal conductivity before compression (e.g., when the compression is under a pressure of about 50 PSI). In other words, the thermal conductivity of aerogel thermal barriers is robust to compression. In some aspects, the robustness to compression may be advantageous in applications of the thermal barrier to battery cells since battery cells expand and contract. In some aspects, the thermal barriers disclosed herein may maintain thermal protection throughout the range of compression caused by the expansion and contraction of the battery cells, e.g., battery volume changes during charge and discharge. Some Aerogel materials may exhibit very low heat conductivity in both a compressed and an uncompressed state. In some aspects, the thermal barrier includes a thermal conductivity less than about 0.03 W / (m·K), less than about 0.025 W / (m·K), less than about 0.02 W / (m·K), less than about 0.15 W / (m·K), or less than about 0.10 W / (m·K). In one aspect, a thermal barrier including an aerogel includes a heat conductivity less than about 0.02 W / (m·K).

[0056] The graph 250 of Figure 2C shows that a proportion (slope of lines illustrated) is independent of a number of cell subdivisions and a number of thermal barriers. For example, a slope of first line 270 using the uncompressed Y-axis 252 is 8mm / 25kwh / m2. This reduces to 320 cm3 / kilowatt hour (cm3 / kwh). Stated another way, a volume of thermal barrier divided by an amount of energy stored defines a proportion that is equal to a slope of the line.

[0057] In one example, the first line 270 in Figure 2C indicates a proportion (slope) that defines a thickness of thermal barrier that is configured to prevent a thermal runaway condition from spreading from a first cell or cell subdivision across a thermal barrier to an adjacent cell or cell subdivision. In an aspect, at a given cell areal energy density, any thickness of thermal barrier above line 270 is sufficient to prevent a thermal runaway from spreading beyond the thermal barrier. Conversely, in an aspect, any thickness below line 270 may not be sufficient to prevent a thermal runaway from spreading beyond the thermal barrier. A thermal runaway may spread beyond the thermal barrier if given enough time if the thickness is below line 270. As shown in Fig.2C, an energy storage system with a cell areal energy density of 25 kwh / m2, and an uncompressed thermal barrier thickness of at least 8 mm will prevent a thermal runaway from spreading beyond the thermal barrier.AAI-107-A-PCT (1189-WO01) 13 Similarly, as shown in Fig.2C, a thermal barrier thickness of at least 4mm will prevent thermal runaway from spreading beyond the thermal barrier. Still referring to Fig. 2C, for a cell areal energy density of 25 kwh / m2, a thermal barrier having an uncompressed thickness of less than 8 mm or compressed thickness of less than 4 mm may delay spreading a thermal runaway beyond the thermal barrier, but thermal runaway may be uncontained by the thermal barrier as time goes by.

[0058] In one example, a second line 260 in Figure 2C is shown that indicates a proportion (slope) that defines a thickness of thermal barrier that is configured to delay a thermal runaway from breaching across a thermal barrier to a next adjacent battery cell or cell subdivision for five minutes. A five-minute delay may be considered acceptable in some battery powered devices such as motor vehicles. As shown in Fig.2C, at a given cell areal energy density, any thickness of thermal barrier above line 260 is sufficient to delay a thermal runaway from breaching across a thermal barrier for at least 5 minutes. It follows, then, that a thickness of the thermal barrier that is below line 260 may not be sufficient to delay the thermal runaway from breaching across the thermal barrier for at least 5 minutes. A thermal runaway may breach the thermal barrier in under 5 minutes if the thickness of the thermal barrier is below line 260. As shown in Fig.2C, considering an energy storage system with a cell areal energy density of 25 kwh / m2as an example, an uncompressed thermal barrier thickness of at least 5 mm will delay the thermal runaway from breaching across the thermal barrier for at least 5 minutes. Similarly, as shown in Fig.2C, for a 25 kwh / m2energy storage system, a compressed thermal barrier thickness of at least 2.5 mm will delay the thermal runaway from breaching across the thermal barrier for at least 5 minutes. Still referring to Fig.2C, it follows that for a 25 kwh / m2energy storage system any uncompressed thickness of less than 5 mm or compressed thickness of less than 2.5 mm may not be sufficient to delay the thermal runaway from spreading beyond the thermal barrier for at least 5 minutes.

[0059] In aspects, the slope of lines 260 and 270 in Fig.2C may be used to determine a minimum volume of the thermal barrier for the battery module 200, to delay (line 260) or prevent (line 270) thermal runaway from breaching the thermal barrier. It is to be understood that certain conditions apply to using the slope of the lines in Fig.2C for volume calculations: Only stored energy that is “protected” by thermal barriers that are included in the calculations should be included. Energy can transfer across a thermal barrier in 1 direction at a time. (Based on 2ndLaw of Thermodynamics.) For example, asAAI-107-A-PCT (1189-WO01) 14 shown in Fig.2D, one side of cell 210 is not “protected” by a thermal barrier. The energy stored in a battery cell or a battery module is the rated or the nominal energy. The energy released during a thermal runaway may, in some cases, be a few times greater than the rated or nominal energy. Since we assume that the storage cells are thermally homogeneous, the “unprotected” side of cell subdivision 210 will account for one half of the stored energy of the cell subdivision. If we assume that thermal energy is transferred to the left in Fig.2D, then one half of the stored energy of each cell is relevant to sizing the two thermal barriers 214. If we assume that the thermal energy is transferred from both sides of cell subdivision 212, then cell subdivision 210 would be considered “unprotected” because energy can transfer through the thermal barrier in one direction at a time. In both methods of analysis, the total amount of stored energy that is relevant to sizing the two thermal barriers using the slope of lines in Fig.2C is the total storage of one cell subdivision 210 or 212. As such, the total amount of stored energy to include in the calculations for the system shown in Fig.2A and Fig.2D is the stored energy of one cell subdivision 210 or 212. An example of how to determine the minimum volume of the thermal barrier for the battery module 200 shown in Fig.2A and Fig.2D is as follows: The slope of line 260 is about 200 cm3 / kilowatt hour, which is the volume (cm3) of the thermal barrier divided by an amount of energy (kilowatt hour) stored in cell subdivision 212. The slope of line 260 indicates at least about 200 cm3volume of thermal barrier is needed for each kilowatt hour energy stored in the “protected” portion of battery module 200 to delay the occurrence of a thermal runaway by at least about 5 minutes. As a demonstration, assume the energy stored in cell subdivision 212 is 0.275 kwh. 0.275 kwh × 200 cm^3 / kwh = 55 cm^3. Similarly, the slope of line 270 is about 320 cm3 / kilowatt hour, which indicates at least about 320 cm3volume of thermal barrier is needed for each kilowatt hour energy stored in the “protected” portion of battery module 200 to prevent a thermal runaway from breaching a thermal barrier. A battery module 200 with a proportion of thermal barrier volume to “protected” energy storage that is greater than the proportion (slope) of line 260 provides at least 5 minutes delay of the thermal runaway breaching a thermal barrier. A battery module 200 with a proportion of thermal barrier volume to “protected” energy storage that is greater than the proportion (slope) of line 270 may prevent thermal runaway from breaching a thermal barrier for a long period of time that begins with the beginning of the thermal runaway. In an aspect, the long period of time may be greater than 24 hours. In an aspect, the long period of time may be greater than 48 hours. In an aspect, the longAAI-107-A-PCT (1189-WO01) 15 period of time may be greater than 72 In an aspect, the long period of time may be greater than 96 hours. In an aspect, the long period of time may be greater than two weeks.

[0060] Although a proportion of 320 cm3 / kilowatt hour for line 270 and a proportion of 200 cm3 / kilowatt hour for line 260 is illustrated in the example graph 250, the invention is not so limited. Material properties of insulating materials (e.g., aerogel, resin, polymer, foam, mica, ceramic) and how the materials are structurally arranged can affect the properties (e.g., thermal conductivity) of the thermal barrier and therefore affect the specific proportions (slopes) of the graph 250 in Figure 2C. In some aspects the proportion (slope) of line 260 ranges from about 100 cm3 / kilowatt hour to about 350 cm3 / kilowatt hour. In some aspects the proportion (slope) of line 270 ranges from about 150 cm3 / kilowatt hour to about 500 cm3 / kilowatt hour. In some aspects the volume of the thermal barriers in the battery module 200 ranges from about 100 cm3 / kilowatt to about 500 cm3 / kilowatt, from 150 cm3 / kilowatt to about 350 cm3 / kilowatt, or from 200 cm3 / kilowatt to about 320 cm3 / kilowatt. In one example, a middle region 262 between line 260 and line 270 of graph 250 indicates a design envelope for thermal barriers in a battery module where a barrier effectiveness specification is between a five minute delay (indicated by line 260) and a substantially unlimited containment time (indicated by line 270). In an aspect, a substantially unlimited containment time may be at least about 8 hours. In an aspect, a substantially unlimited containment time may be at least about 24 hours. In an aspect, a substantially unlimited containment time may be at least about 96 hours. In an aspect, a substantially unlimited containment time may be at least about 8 hours to at least about 96 hours.

[0061] Fig.3 shows one example of a battery module 300 in an exploded view. The battery module 300 includes a number of battery cells 302 that include electrodes 304. The battery cells 302 define a cross section area equal to a height 307 times a width 306. In the example of Fig.3, each cell 302 has a thickness 308.

[0062] One or more thermal barriers 310 are shown between battery cells 302. The one or more thermal barriers 310 have a thickness 312. In some aspects, the thermal barriers 310 each have a height that is substantially the same as the height 307 of a battery cell and a width that is substantially the same as the width 306 of the battery cell depicted in Fig.3. with respect to the battery cells 302. In an aspect based the illustrations in Fig.3, a volume of a given thermal barrier 310 is defined as the product of height 307, width 306 and thickness 312. In an aspect based on the proportions illustrated in Fig.2C, a volume ofAAI-107-A-PCT (1189-WO01) 16 a given thermal barrier 310 divided by one of an amount of energy stored in a battery cell adjacent to the thermal barrier 310 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C. Likewise, a volume of all thermal barriers 310 in the battery module 300 divided by one half of an amount of energy stored in all battery cells 302 of the battery module 300 that are protected by the thermal barriers 310 defines a proportion as indicated by the lines 260, 270 on the graph 250 in Fig.2C.

[0063] It is to be understood that Total Energy relevant to the slope × total energy calculation of the total volume of Thermal Barriers may be reduced by a correction factor for the number of ends protected by a thermal barrier. If 2 ends are covered by a thermal barrier, the number of cells included in the calculation of Total Energy relevant to Thermal Barrier Sizing is increased by 1. If 1 end is covered by a thermal barrier, the number of cells included in the calculation of Total Energy relevant to Thermal Barrier Sizing is not corrected. If none of the ends are covered by a thermal barrier, the number of cells included in the calculation of Total Energy relevant to Thermal Barrier Sizing is reduced by 1. It is to be further understood that as the number of cells increases, the error introduced by not applying the correction factor may be negligible. The percentage of potential error in calculating the Thermal Barrier Sizing is about 1 divided by the number of cells (or cell subdivisions) multiplied by 100. Therefore, if there are 5 cells (or cell subdivisions) in a module, an error of less than + / - 20% may be introduced by not considering the end effects. If there are 10 cells (or cell subdivisions) in a module, an error of less than + / - 10% may be introduced by not considering the end effects. If there are 50 cells (or cell subdivisions) in a module, an error of less than + / - 2% may be introduced by not considering the end effects.

[0064] A demonstration that uses the battery module 300 depicted in Fig.3 with the graph 250 in Fig.2C follows:AAI-107-A-PCT (1189-WO01) 17 Table 1: Demonstration of Energy Density of Cells in Fig.3 E T l E A f E h A l E ls ଶଶଶTable 2: Demonstration of Determining Thickness or Volume of Thermal Barriers in Fig.3 ^ ଷAAI-107-A-PCT (1189-WO01) 18 200 cm3 / kwh 10.2kwh ଶ3 27.5cmଷ(Line 260)mଶ× × 3 ଷଷଷAAI-107-A-PCT (1189-WO01) 19 Table 3: Demonstration of Volume of Thermal Barriers Based on Total Energy in E f T l E l f li T l h ଷa e s ows a , e e a pe, e oa o u e o e mal Barriers (TVTB) (82.6 cm3) calculated using the correction for Total Energy is the same as the TVTB (82.5 cm3) calculated in Table 2 for 3 thermal barriers using line 260. The difference of 0.1 cm3, which is negligible, is caused by a difference in rounding of intermediate values in the calculations. Thus, the equivalence of the results from the Areal Density and the Total Energy methods disclosed herein is demonstrated.

[0066] Fig.4 shows another example of a battery module 400 in an exploded view. Battery module 400 includes one or more thermal barriers 410 with width 406 to a height 407 ratio of greater than about 1.5. The height to width ratio greater than about 1.5 is designed to fit the similarly designed battery cells 402. Battery cells 402 with such ratio increases the surface area (e.g., the height 407 times the width 406) compared to the battery cells with a height to width ratio less than about 1.5. The increased surface area of the battery cells 402 requires less volume of thermal barriers 410 according to the graph 250 in Fig.2C. As a result, the battery module 400 includes thermal barriers 410 every several battery cells 402 instead of every other battery cells as shown in Fig.3.

[0067] The battery module 400 in Fig.4 includes a number of battery cells 402 that include electrodes 404. In the example of Fig.4, the number of battery cells 402 are divided into a number of cell subdivisions 401, where each cell subdivision 401 includes multiple battery cells 402 separated by one or more thermal barriers 410. The battery cellsAAI-107-A-PCT (1189-WO01) 20 402 define a cross section area equal to a 407 times a width 406. In the example of Fig.4, each cell subdivision 401 has a thickness 408.

[0068] As noted above, one or more thermal barriers 410 are shown between battery cells 402. The one or more thermal barriers 410 have a thickness 412. In some aspects, the thermal barriers 410 each have a height that is substantially the same as the height 407 and a width that is substantially the same as the width 406 depicted in Fig.4 with respect to the cell subdivisions 401. In an aspect based on the illustrations in Fig.4, a volume of a given thermal barrier 410 may be defined the product of height 407, width 406 and thickness 412. Following the proportions illustrated in Fig.2C, a volume of a given thermal barrier 410 divided by one half of an amount of energy stored in a cell subdivision adjacent to the thermal barrier 410 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C. Likewise, a volume of all thermal barriers 410 in the battery module 400 divided by one half of an amount of energy stored in all battery cells 402 and / or all cell subdivisions 401 of the battery module 400 that are protected by the thermal barriers 410 defines a proportion as indicated by lines 260, 270 on the graph 250 in Fig.2C.

[0069] As disclosed herein, it is to be understood that Total Energy relevant to the slope × total energy calculation of the total volume of Thermal Barriers may be reduced by a correction factor for the number of ends protected by a thermal barrier.

[0070] A demonstration that uses the battery module 400 depicted in Fig.4 with the graph 250 in Fig.2C follows:AAI-107-A-PCT (1189-WO01) 21 Table 4: Demonstration of Energy Density of Cell Subdivisions in Fig.4 E T l A f E h A l E ll ^ ଶଶଶTable 5: Demonstration of Determining Thickness or Volume of Thermal Barriers in Fig.4 ^ ଷAAI-107-A-PCT (1189-WO01) 22 Table 5: Demonstration of or Volume of Thermal Barriers in Fig.4 l f li Th l B i l f T l ଷ 2 ଷ

[0071] For a given battery module, the total volume of the thermal barrier TVTBcan be calculated using line 260 to delay the thermal runaway (e.g., breaching of the thermal barrier) by 5 minutes. The total volume of the thermal barrier TVTBcan be calculated using line 270 to prevent a thermal runaway from breaching the thermal barrier. In an aspect, the total volume of the thermal barrier TVTBcould be implemented in one thermal barrier dividing the battery module into two subdivisions. Alternatively, the total volume of the thermal barrier TVTBcould be two thermal barriers dividing the battery module to three subdivisions, three thermal barriers dividing the battery module to four subdivisions, etc.AAI-107-A-PCT (1189-WO01) 23 The total volume of the thermal barriers may be implemented as up to X-1 thermal barriers dividing the battery module into X subdivisions, each subdivision has a minimum of one battery cell, where X is the number of battery cells in the battery module. It is to be understood that X and Ncell_sub may be used interchangeably in the present disclosure to represent the number of cell subdivisions. Each subdivision may include equal quantities of battery cells or different quantities of battery cells. Since the total volume of the thermal barrier(s) TVTBis based on the Total Energy (ET), not the size of the individual subdivisions, the total volume of the thermal barrier(s) TVTB is not necessarily changed by implementing a different quantity of thermal barriers or subdivisions. If the Total Energy (ET) is not changed, dividing a battery module into more subdivisions separated by more thermal barriers will result in a smaller average thermal barrier thickness. As long as the total volume of the thermal barriers meets the requirements of line 260 and 270 in Fig.2C, the thermal barriers will provide 5 minutes thermal runaway delay (line 260) or prevent a thermal runaway from breaching the thermal barriers (line 270).

[0072] It is to be understood that if the cell subdivisions are not equally sized (in terms of energy), then the thermal barriers associated with the unequally sized subdivisions have a corresponding variation in thickness. The total volume of the thermal barrier(s) TVTB is implemented in the individual thermal barriers proportionally to the size of the corresponding cell subdivisions.

[0073] In an example shown in Table 6, if the total energy stored in all the battery cells in the battery module is E*, the total thickness T of the thermal barrier needed for the battery module can be calculated by the slopes of the line 260 or 270 in Fig.2C. The total volume of the thermal barrier V needed for the battery module is T multiplied by the surface area of the thermal barrier (ABHT). The volume of each thermal barrier V’ and thickness of each thermal barrier T’ are V and T respectively if the battery module is divided by one thermal barrier into two subdivisions. The volume V’ and thickness T’ of each thermal barrier needed are V / 2 and T / 2 if the battery module is divided by two thermal barriers into three subdivisions (assuming each of the three subdivisions are equally sized in terms of energy). The maximum quantity of thermal barriers is X-1, where X is the total quantity of battery cells in the battery module. In such a case (i.e., implementing the maximum quantity of thermal barriers), each subdivision has exactly one battery cell. In other words, each battery cell is divided by thermal barriers from other battery cells. The volume V’ andAAI-107-A-PCT (1189-WO01) 24 thickness T’ of each thermal barrier are V / 1) and T / (X-1). There are no thermal barriers at the ends of the battery module in this case.

[0074] A demonstration that uses the battery module 300 and 400 depicted in Figs.3 and 4 with the graph 250 in Fig.2C follows. The energy of each cell is 0.275kwh. The area of each cell subdivision heat transfer surface (ACSHT) is the height 0.091m multiply the width 0.400m, which equals 0.0364m2. the number of the number of heat transfer surfaces for each cell subdivision are 2. Table 6: Demonstration of Determining Thickness of Thermal Barriers in Fig.3 and Fig.4.^^ ^^ ^^AAI-107-A-PCT (1189-WO01) 25 Table 6: Demonstration of of Thermal Barriers in Fig.3 and Fig.4. N mber N mber Ener Areal Ener Slo e of Thermal Barrier Total^^ ଷ. view. The battery module 500 includes one or more thermal barriers 510 placed in a housing 520. The lengths of the thermal barriers 510 span across a width of the housing 520, thereby dividing the housing 520 into multiple compartments. The multiple compartments contain the subdivisions of battery cells 502 and prevent thermal propagation therebetween in extreme conditions. The extreme conditions may include, but are not limited to, mechanical damage, overheating, and thermal runaway.

[0076] The battery module 500 in Fig.5 includes a number of battery cells 502. In the example of Fig.5, the number of battery cells 502 are divided into a number of cell subdivisions 501, where each cell subdivision 501 includes multiple battery cells 502 separated by one or more thermal barriers 510. In some aspects, each of the thermal barriers 510 have a height that is substantially the same as the height and a width that is substantially the same as the width of each of the battery cells 502 depicted in Fig.5. In an aspect based on the illustrations in Fig.5, the number of battery cells 502 and number of cell subdivisions 501 are located within a housing 520. Widths of the battery cells 502 span across a width of the housing 520. In one aspect, the housing 520 includes a thermal barrier material. In one example, the thermal barrier material included in the housing 520 includes aerogel material. In one example, a lid 522 is further included and fits together with the housing 520 to fully enclose the number of battery cells 502 and number of cell subdivisions 501. In one example, the lid 522 includes the thermal barrier material. In one example, the thermal barrier material included in the lid 522 includes aerogel material. It isAAI-107-A-PCT (1189-WO01) 26 to be understood that although portions of housing 520 and lid 522 may include the thermal barrier material, the portions of the housing 520 and lid 522 may or may not be thermal barriers 510.

[0077] Following the proportions illustrated in Fig.2C, a volume of a given thermal barrier 510 divided by one half of an amount of energy stored in a cell subdivision adjacent to the thermal barrier 510 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C. Likewise, a volume of all thermal barriers 510 in the battery module 500 divided by one half of an amount of energy stored in all battery cells 502 and / or all cell subdivisions 501 of the battery module 500 that are protected by the thermal barriers 510 defines a proportion as indicated by lines 260, 270 on the graph 250 in Fig.2C.

[0078] As disclosed herein, it is to be understood that Total Energy relevant to the slope × total energy calculation of the total volume of thermal barriers 510 may be reduced by a correction factor for the number of ends protected by a thermal barrier. Fig.6 shows another example of a battery module 600 in an exploded view. One or more thermal barriers 610 are integrated with a housing 620 in Fig.6. The thermal barriers 610 integrated with the housing 620 divide the housing into multiple compartments. Each compartment confines a subdivision of the battery cells 602. By the confinement of the integrated thermal barriers 610, relative motion of the battery cells 602 are restrained with respect to the corresponding compartment in which the battery cells 602 are disposed is reduced during operation and extreme conditions (e.g., thermal runaway or mechanical impact). The relative motion of the battery cells 602 may be reduced by a cushioning effect of resilient integrated thermal barriers 610. The resilient integrated thermal barriers 610 may brace the battery cells 602 in a position in the housing 620 and reduce, compared to relative motion without the thermal barriers 610, relative motion between the battery cells 602 and corresponding compartment of the housing 620.

[0079] The battery module 600 in Fig.6 includes a number of battery cells 602. In the example of Fig.6, the number of battery cells 602 are divided into a number of cell subdivisions 601, where each cell subdivisions 601 include multiple battery cells 602 separated by one or more thermal barriers 610. In some aspects, each of the thermal barriers 610 have a height that is substantially the same as the height and a width that is substantially the same as the width of each of the battery cells 602 depicted in Fig.6. In an aspect based on illustrations in Fig.6, the number of battery cells 602 and number of cellAAI-107-A-PCT (1189-WO01) 27 subdivisions 601 are located within a 620. In one example, the housing 620 includes thermal barrier material. In one example, the thermal barrier material included in the housing 620 includes aerogel material. In the example of Fig.6, the one or more thermal barriers 610 are integrally formed with the housing 620. In one example, a lid 622 is further included and fits together with the housing 620 to fully enclose the number of battery cells 602 and number of cell subdivisions 601. In one example, the lid 622 includes thermal barrier material. In one example, the thermal barrier material included in the lid 622 includes aerogel material.

[0080] Following the proportions illustrated in Fig.2C, a volume of a given thermal barrier 610 divided by on half of an amount of energy stored in a cell subdivision adjacent to the thermal barrier 610 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C. Likewise, a volume of all thermal barriers 610 in the battery module 600 divided by one half of an amount of energy stored in all battery cells 602 and / or all cell subdivisions 601 of the battery module 600 that are protected by the thermal barriers defines a proportion as indicated by lines 260, 270 on the graph 250 in Fig.2C.

[0081] As disclosed herein, it is to be understood that Total Energy relevant to the slope × total energy calculation of the total volume of thermal barriers 510 may be reduced by a correction factor for the number of ends protected by a thermal barrier.

[0082] Fig.7A shows an example of a battery pack 700 in an exploded view. The battery pack 700 includes cooling channels 710 integrated in housing 720 and thermal barriers 712 between battery cells 702. The cooling channels 710 includes coolants flow therein to remove heat from the battery pack 700. The combinations of the cooling channels 710 and the thermal barriers 712 work together to prevent thermal runaway by removing excessive heat and by preventing heat propagation between compartments.

[0083] The battery pack 700 includes a number of battery modules 728. One or more of the modules 728 include a number of battery cells 702 separated by one or more thermal barriers 712. In one aspect, the thermal barriers 712 are separate from and assembled to the battery pack 700. In other words, the thermal barriers 712 are not integrated in the housing 720. The non-integrated thermal barriers 712 may provide flexibility in battery pack assembly processes.

[0084] Fig.7A illustrates an example of how a battery pack 700 may be assembled: Arrow 726 indicates that each thermal barrier 712 is disposed between two battery cellsAAI-107-A-PCT (1189-WO01) 28 702. The two battery cells 702 are in a compartment defined by the housing 720, respective cooling channel(s) 710, and, optionally, the lid 722.

[0085] In the example of Fig.7A, the number of battery cells 702 are located within a housing 720. In one example, the housing 720 includes thermal barrier material. In one example, the thermal barrier material included in the housing 720 includes aerogel material. In one example, a lid 722 is further included and fits together with the housing 720 to fully enclose the number of battery cells 702 and number of battery modules 728. In one example, the lid 722 includes thermal barrier material. In one example, the thermal barrier material included in the lid 722 includes aerogel material.

[0086] In one aspect, for analysis of thermal barrier sizing and consistency within this disclosure, cell subdivisions 701 may include portions of more than one battery module 728. For example, as illustrated in Fig.7B, each cell subdivision 701 includes a cooling channel 710 disposed between two battery cells 702.

[0087] In the example of Fig.7A, a number of cooling channels 710 are further included. The number of cooling channels 710 are shown separating one or more of the battery modules 728 from one another. At least one surface of the battery cells 702 is in direct contact with the cooling channels 710. Stated another way, the thermal barriers 712 are between the battery cells 702 but not between the battery cells 702 and the cooling channels 710. Inclusion of the number of cooling channels 710 may further facilitate temperature regulation within the battery pack 700.

[0088] One example of cooling channels includes active cooling channels where a medium such as fluid or air is pushed through the channels 710 to regulate an amount of cooling. Another example of cooling channels includes passive cooling channels where an interior of the channels 710 is exposed to an external environment and heat can be passively removed through motion of air to regulate an amount of cooling. An additional example of cooling channels includes heat absorbing materials stored therein, such as phase change materials, other heat absorbing materials, or combinations thereof.

[0089] Fig.8 shows another example of a battery pack 800 in an exploded view.

[0090] The battery pack 800 in Fig.8 includes a number of battery modules 801. One or more of the modules 801 include a number of battery cells 802 separated by one or more thermal barriers 812. In the example of Fig.8, the number of battery cells 802 are located within a housing 820. In the example illustrated in Fig.8, each battery module 801 includes more than two battery cells 802, and each cell 802 is separated by a thermal barrierAAI-107-A-PCT (1189-WO01) 29 812, although the present disclosure is not limited. Multiple battery cells 802 may be included in a cell subdivision as illustrated in other examples above. Different numbers of battery cells 802 in each battery module 801 may be used depending on electrical and thermal needs of a device being powered by the battery pack 800. In an aspect, the thickness and volume of thermal barrier 812 in each battery module 801 is determined according to the lines 260 and 270 in the graph 250 in Fig.2C.

[0091] In one example, the housing 820 includes thermal barrier material. In one example, the thermal barrier material included in the housing 820 includes aerogel material. In one example, a lid 822 is further included and fits together with the housing 820 to fully enclose the number of battery cells 802 and number of battery modules 801. In one example, the lid 822 includes thermal barrier material. In one example, the thermal barrier material included in the lid 822 includes aerogel material.

[0092] Following the proportions illustrated in Fig.2C, a volume of a given thermal barrier 812 divided by one half of an amount of energy stored in a battery cell 802 adjacent to the thermal barrier 812 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C.

[0093] In the example of Fig.8, a number of cooling channels 810 are further included. The number of cooling channels 810 are shown separating one or more of the battery modules 801 from one another. Inclusion of the number of cooling channels 810 further facilitates temperature regulation within the battery pack 800. One example of cooling channels includes active cooling channels where a medium such as fluid or air is pushed through the channels 810 to regulate an amount of cooling. Another example of cooling channels includes passive cooling channels where an interior of the channels 810 is exposed to an external environment and heat can be passively removed through motion of air to regulate an amount of cooling. In an aspect, a cooling channel may include one or more of: coolant, phase change materials, conductive materials, intumescent materials, and fire extinguishing materials.

[0094] In some aspects, cooling channels may have heat absorbing materials stored or encapsulated therein. In some examples, the heat absorbing materials may include phase change materials, crystalline hydrates, other heat absorbing materials, or combinations thereof. As used herein “phase change material” means a substance which absorbs sufficient energy at phase transition to provide useful cooling. The phase transition may be from a first state of matter (e.g., solid, liquid, or gas) to another state of matter. The phaseAAI-107-A-PCT (1189-WO01) 30 transition may also be between non- of matter, such as the conformity of crystals, where the phase change material transitions from conforming to one crystalline structure to conforming to another, which may be a different energy state.

[0095] Fig.9 shows another example of a battery pack 900 in an exploded view. The battery pack 900 includes a thermal barrier 910 between two cooling channels 912 and 913. The thermal barrier 910 separates the housing 920 into multiple compartments that confine the thermal runaway from propagating to adjacent compartments. The cooling channels 912 and 913 next to (i.e., in direct contact with) the thermal barrier 910 remove excessive heat under extreme conditions, such as overheating and thermal runaway.

[0096] In an aspect depicted in Fig.9, the battery pack 900 includes a number of battery modules 901. One or more of the modules 901 include a number of battery cells 902. In the example of Fig.9, a first cooling channel 912 and a second cooling channel 913 are included on opposite sides of a number of thermal barriers 910. Similar to examples described above, inclusion of the cooling channels 912 and 913 further facilitates temperature regulation within the battery pack 900. One example of cooling channels includes active cooling channels where a medium such as fluid or air is pushed through the cooling channels 912 and 913 to regulate an amount of cooling. Another example of cooling channels includes passive cooling channels where an interior of the cooling channels 912 and 913 is exposed to an external environment and heat can be passively removed through motion of air to regulate an amount of cooling.

[0097] In the example of Fig.9, the number of battery cells 902 are located within a housing 920. In one example, the housing 920 includes thermal barrier material (e.g., in the thermal barriers 910). In one example, the thermal barrier material included in the housing 920 includes aerogel material. In one example, a lid 922 is further included and fits together with the housing 920 to fully enclose the number of battery cells 902 and number of battery modules 901. In one example, the lid 922 includes thermal barrier material. In one example, the thermal barrier material included in the lid 922 includes aerogel material.

[0098] According to Fig.2C, a volume of a given thermal barrier 910 divided by one half of an amount of energy stored in a battery cell 902 adjacent to the thermal barrier 910 defines a proportion as indicated by the respective slopes of the lines 260, 270 on the graph 250 in Fig.2C.

[0099] Battery modules and / or battery packs as described above may be used in a number of electronic devices. Fig.10 illustrates an example electronic device 1000 thatAAI-107-A-PCT (1189-WO01) 31 includes a battery module 1010. The module 1010 is coupled to functional electronics 1020 by circuitry 1012. In the example shown, the battery module 1010 and circuitry 1012 are contained in a housing 1002. A charge port 1014 is shown coupled to the battery module 1010 to facilitate recharging of the battery module 1010 when needed.

[0100] In one example, the functional electronics 1020 include devices such as semiconductor devices with transistors and storage circuits. Examples of the devices include, but are not limited to, telephones, computers, display screens, navigation systems, etc.

[0101] Fig.11 illustrates another electronic system that utilizes battery modules that include thermal management systems as disclosed herein. An electric vehicle 1100 is illustrated in Fig.11. The electric vehicle 1100 includes a chassis 1102 and wheels 1122. In the example shown, each wheel 1122 is coupled to a drive motor 1120. A battery module 1110 is shown coupled to the drive motors 1120 by circuitry 1106. A charge port 1104 is shown coupled to the battery module 1110 to facilitate recharging of the battery module 1110 when needed.

[0102] Examples of electric vehicle 1100 include, but are not limited to, consumer vehicles such as cars, trucks, etc. Commercial vehicles such as tractors and semi-trucks are also within the scope of the present disclosure. Although a four wheeled vehicle is shown, the invention is not so limited. For example, two wheeled vehicles such as motorcycles and scooters are also within the scope of the present disclosure.

[0103] To better illustrate the method and apparatuses disclosed herein, a non- limiting list of aspects is provided here:

[0104] Aspect 1 includes a battery module. The battery module includes a plurality of battery cells, wherein the plurality of the battery cells is divided into cell subdivisions, each cell subdivision having a quantity of the battery cells. The battery module includes a thermal barrier disposed adjacent to at least one of the cell subdivisions, wherein the thermal barrier includes an interface in contact with the at least one of the cell subdivisions, wherein the interface defines a cross section area, wherein a volume of the thermal barrier is equal to a thickness of the thermal barrier multiplied by the cross section area. The volume of the thermal barrier divided by one half of an amount of energy stored in the cell subdivision defines a proportion in a range between 100 and 500 cm3per kilowatt hour.AAI-107-A-PCT (1189-WO01) 32

[0105] Aspect 2 includes the module of Aspect 1, wherein the volume of the thermal barrier is an uncompressed volume defined by an uncompressed thickness of a thermal insulation material.

[0106] Aspect 3 includes the battery module of any one of Aspects 1-2, wherein the proportion ranges from about 100 cm3per kilowatt hour to about 350 cm3per kilowatt hour to delay a thermal runaway from propagating across the thermal barrier for at least about 5 minutes.

[0107] Aspect 4 includes the battery module of any one of Aspects 1-2, wherein the proportion ranges from about 150 cm3per kilowatt hour to about 500 cm3per kilowatt hour to prevent a thermal runaway from propagating across the thermal barrier.

[0108] Aspect 5 includes the battery module of any one of Aspects 1-4, wherein the volume of the thermal barrier is a compressed volume of a thermal insulation material defined by a compressed thickness of the thermal insulation material with respect to an uncompressed thickness of the thermal insulation material, and wherein the compressed volume is greater than 50% of an uncompressed volume.

[0109] Aspect 6 includes the battery module of any one of Aspects 1-5, wherein the volume of the thermal barrier is a compressed volume of a thermal insulation material defined by a compressed thickness of the thermal insulation material with respect to an uncompressed thickness of the thermal insulation material, and wherein the proportion is in a range between 50 cm3per kilowatt hour and 250 cm3per kilowatt hour.

[0110] Aspect 7 includes the battery module of any one of Aspects 1-6 wherein the thermal barrier has a heat conductivity less than about 0.02 W / (m·K).

[0111] Aspect 8 includes the battery module of any one of Aspects 1-7 wherein the thermal barrier includes aerogel.

[0112] Aspect 9 includes the battery module of any one of Aspects 1-8 wherein the aerogel includes silica aerogel.

[0113] Aspect 10 includes the battery module of any one of Aspects 1-9 wherein each cell subdivision includes one cell, and wherein the cell subdivisions are separated by a respective instance of the thermal barrier.

[0114] Aspect 11 includes the battery module of any one of Aspects 1-10 wherein at least some of the cell subdivisions include multiple battery cells.

[0115] Aspect 12 includes the battery module of any one of Aspects 1-11 wherein the battery cells include lithium nickel manganese cobalt (NMC) oxide battery cells.AAI-107-A-PCT (1189-WO01) 33

[0116] Aspect 13 includes the module of any one of Aspects 1-12 wherein the number of battery cells include prismatic battery cells.

[0117] Aspect 14 includes the battery module of any one of Aspects 1-13, further including a housing and a lid to contain the cell subdivisions, wherein the thermal barrier is integrated with the housing.

[0118] Aspect 15 includes a battery module. The battery module includes a plurality of battery cells, wherein a cross section area of battery cells in the plurality of battery cells define a heat transfer surface, and one or more thermal barriers dividing the plurality of battery cells into cell subdivisions in a number of cell subdivisions, each of the cell subdivisions having a cell subdivision energy storage capacity, wherein the one or more thermal barriers are formed from a volume of thermal insulation material. The battery module wherein an areal energy density is equal to one half of the cell subdivision energy storage capacity divided by the cross section area, and wherein the volume of thermal insulation material divided by one half of the cell subdivision energy storage capacity defines a proportion of at least 320 cm3per kilowatt hour.

[0119] Aspect 16 includes the battery module of Aspect 15, wherein the proportion is multiplied by a thickness compression factor to adjust the proportion in relation to compression of the one or more thermal barriers.

[0120] Aspect 17 includes the battery module of any one of Aspects 15-16, wherein the thickness compression factor is 50 percent and the proportion is at least 160 m3per kilowatt hour.

[0121] Aspect 18 includes a battery pack. The battery pack includes a quantity of battery modules within a housing, each battery module including: a plurality of battery cells, wherein a cross section area of battery cells in the plurality of battery cells define a heat transfer surface; and one or more thermal barriers dividing the plurality of battery cells into cell subdivisions in a number of cell subdivisions, each of the cell subdivisions having a cell subdivision energy storage capacity, wherein the one or more thermal barriers are formed from a volume of thermal insulation material. The battery pack wherein an areal energy density is equal to one half of the cell subdivision energy storage capacity divided by the cross section area, wherein the volume of thermal insulation material divided by one half of the cell subdivision energy storage capacity defines a proportion in a range between 100 cm3per kilowatt hour and 500 cm3per kilowatt hour, and wherein at least two of theAAI-107-A-PCT (1189-WO01) 34 battery modules in the quantity of battery are separated by a cooling channel within the housing.

[0122] Aspect 19 includes the battery pack of Aspect 18, wherein the cooling channel comprises one or more of: a coolant, a phase change material, a conductive material, an intumescent material, and a fire extinguishing material.

[0123] Aspect 20 includes the battery pack of any one of Aspects 18-19, wherein the cooling channel comprises two cooling walls separated by a thermal barrier.

[0124] Aspect 21 includes the battery pack of any one of Aspects 18-20, wherein the cell subdivision energy storage capacity used to define the proportion is a capacity for energy to be stored in the battery cells of the cell subdivision minus an energy removed by the cooling channel.

[0125] The above description is intended to be illustrative, and not restrictive. For example, the above-described aspects (or one or more aspects thereof) may be used in combination with each other. Other aspects 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, 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.

[0126] Although an overview of the inventive subject matter has been described with reference to specific aspects, various modifications and changes may be made to these aspects without departing from the broader scope of embodiments of the present disclosure. Such aspects of the inventive subject matter may be referred to herein, individually or collectively, by the term “invention” merely for convenience and without intending toAAI-107-A-PCT (1189-WO01) 35 voluntarily limit the scope of this to any single disclosure or inventive concept if more than one is, in fact, disclosed.

[0127] The aspects illustrated herein are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed. Other aspects may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. The Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[0128] As used herein, the term “or” may be construed in either an inclusive or exclusive sense. Moreover, plural instances may be provided for resources, operations, or structures described herein as a single instance. Additionally, boundaries between various resources, operations, modules, engines, and data stores are somewhat arbitrary, and particular operations are illustrated in a context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within a scope of various embodiments of the present disclosure. In general, structures and functionality presented as separate resources in the example configurations may be implemented as a combined structure or resource. Similarly, structures and functionality presented as a single resource may be implemented as separate resources. These and other variations, modifications, additions, and improvements fall within a scope of embodiments of the present disclosure as represented by the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

[0129] The foregoing description, for the purpose of explanation, has been described with reference to specific example embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the possible example embodiments to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The example embodiments were chosen and described in order to best explain the principles involved and their practical applications, to thereby enable others skilled in the art to best utilize the various example embodiments with various modifications as are suited to the particular use contemplated.

[0130] It will also be understood that, although the terms “first,” “second,” and so forth may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. ForAAI-107-A-PCT (1189-WO01) 36 example, a first contact could be termed a contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the present example embodiments. The first contact and the second contact are both contacts, but they are not the same contact.

[0131] The terminology used in the description of the example embodiments herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used in the description of the example embodiments and the appended examples, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0132] As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

Claims

AAI-107-A-PCT (1189-WO01) 37 What is claimed is:

1. A battery module, comprising: a plurality of battery cells, wherein the plurality of the battery cells is divided into cell subdivisions, each cell subdivision having a quantity of the battery cells; and a thermal barrier disposed adjacent to at least one of the cell subdivisions, wherein the thermal barrier includes an interface in contact with the at least one of the cell subdivisions, wherein the interface defines a cross section area; wherein a volume of the thermal barrier is equal to a thickness of the thermal barrier multiplied by the cross section area; and wherein the volume of the thermal barrier divided by one half of an amount of energy stored in the cell subdivision defines a proportion in a range between 100 and 500 cm3per kilowatt hour.

2. The battery module of claim 1, wherein the volume of the thermal barrier is an uncompressed volume defined by an uncompressed thickness of a thermal insulation material.

3. The battery module of claim 2, wherein the proportion ranges from about 100 cm3per kilowatt hour to about 350 cm3per kilowatt hour to delay a thermal runaway from propagating across the thermal barrier for at least about 5 minutes.

4. The battery module of claim 2, wherein the proportion ranges from about 150 cm3per kilowatt hour to about 500 cm3per kilowatt hour to prevent a thermal runaway from propagating across the thermal barrier.

5. The battery module of claim 1, wherein the volume of the thermal barrier is a compressed volume of a thermal insulation material defined by a compressed thickness of the thermal insulation material with respect to an uncompressed thickness of the thermal insulation material, and wherein the compressed volume is greater than 50% of an uncompressed volume.

6. The battery module of claim 1, wherein the volume of the thermal barrier is a compressed volume of a thermal insulation material defined by a compressed thickness ofAAI-107-A-PCT (1189-WO01) 38 the thermal insulation material with an uncompressed thickness of the thermal insulation material, and wherein the proportion is in a range between 50 cm3per kilowatt hour and 250 cm3per kilowatt hour.

7. The battery module of claim 1, wherein the thermal barrier has a heat conductivity less than about 0.02 W / (m·K).

8. The battery module of claim 1, wherein the thermal barrier includes aerogel.

9. The battery module of claim 8, wherein the aerogel includes silica aerogel.

10. The battery module of claim 1, wherein each cell subdivision includes one cell, and wherein the cell subdivisions are separated by a respective instance of the thermal barrier.

11. The battery module of claim 1, wherein at least some of the cell subdivisions include multiple battery cells.

12. The battery module of claim 1, further including a housing and a lid to contain the cell subdivisions, wherein the thermal barrier is integrated with the housing.

13. A battery module, comprising: a plurality of battery cells, wherein a cross section area of battery cells in the plurality of battery cells define a heat transfer surface; and one or more thermal barriers dividing the plurality of battery cells into cell subdivisions in a number of cell subdivisions, each of the cell subdivisions having a cell subdivision energy storage capacity, wherein the one or more thermal barriers are formed from a volume of thermal insulation material; wherein an areal energy density is equal to one half of the cell subdivision energy storage capacity divided by the cross section area; and wherein the volume of thermal insulation material divided by one half of the cell subdivision energy storage capacity defines a proportion of at least 320 cm3per kilowatt hour.AAI-107-A-PCT (1189-WO01) 39 14. The battery module of wherein the proportion is multiplied by a thickness compression factor to adjust the proportion in relation to compression of the one or more thermal barriers.

15. The battery module of claim 14, wherein the thickness compression factor is 50 percent and the proportion is at least 160 cm3per kilowatt hour.

16. A battery pack, comprising: a quantity of battery modules within a housing, each battery module including: a plurality of battery cells, wherein a cross section area of battery cells in the plurality of battery cells define a heat transfer surface; and one or more thermal barriers dividing the plurality of battery cells into cell subdivisions in a number of cell subdivisions, each of the cell subdivisions having a cell subdivision energy storage capacity, wherein the one or more thermal barriers are formed from a volume of thermal insulation material; wherein an areal energy density is equal to one half of the cell subdivision energy storage capacity divided by the cross section area; wherein the volume of thermal insulation material divided by one half of the cell subdivision energy storage capacity defines a proportion in a range between 100 cm3per kilowatt hour and 500 cm3per kilowatt hour; and wherein at least two of the battery modules in the quantity of battery modules are separated by a cooling channel within the housing.

17. The battery pack of claim 16, wherein the cooling channel comprises one or more of: a coolant, a phase change material, a conductive material, an intumescent material, and a fire extinguishing material.

18. The battery pack of claim 16, wherein the cooling channel includes two cooling walls separated by a thermal barrier.

19. The battery pack of claim 16, wherein the cell subdivision energy storage capacity used to define the proportion is a capacity for energy to be stored in the battery cells of the cell subdivision minus an energy removed by the cooling channel.

Images