Devices, systems, and methods for controlling vent gases and ejecta from thermal runaway events in energy storage systems

Abstract

To provide a material and a system for managing a problem of thermal runaway of a battery module.SOLUTION: A battery module, comprising: a housing including an interior surface, wherein the interior surface is defined by a first end plate and a second end plate that extend between a first sidewall and a second sidewall and between a top plate and a bottom plate; two or more battery cells disposed in an interior space of the housing; and one or more spacer elements disposed between adjacent battery cells, wherein: Wherein each of the spacer elements comprises at least one thermal capacity layer and at least one insulating layer, wherein the insulating layer has a thermal conductivity through a thickness dimension of the insulating layer of less than 50mW / m-K at 25 °C and less than 60mW / m-K at 600 °C; and wherein a portion of each of the spacer elements extends away from the insulating layer and contacts the inner surface of the housing such that a thermal barrier is formed between the adjacent battery cells.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 218,205, filed July 2, 2021, entitled "Materials, Systems, and Methods for Mitigation of Electrical Energy Storage Thermal Events," the entire contents of which are incorporated herein by reference. This application also claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 231,617, filed August 10, 2021, entitled "Devices, Systems, and Methods for Controlling Vent Gases and Ejecta from Thermal Runaway Events in Energy Storage Systems," the entire contents of which are incorporated herein by reference. This application also claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 273,845, filed October 29, 2021, and entitled "Devices, Systems, and Methods for Controlling Vent Gases and Ejecta from Thermal Runaway Events in Energy Storage Systems," the entire contents of which are incorporated herein by reference. This application also claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 275,261, filed November 3, 2021, and entitled "Devices, Systems, and Methods for Controlling Vent Gases and Ejecta from Thermal Runaway Events in Energy Storage Systems," the entire contents of which are incorporated herein by reference.

[0002] The present disclosure generally relates to materials and systems for preventing or mitigating thermal events, such as thermal runaway problems, in energy storage systems. In particular, the present disclosure provides multilayer thermal barrier materials including at least one insulating layer, at least one compressible pad, and one or more optional layers. The optional one or more layers have favorable heat dissipation properties, favorable fire resistance, flame retardancy, and / or abrasion resistance properties, and / or favorable performance for use as a thermal barrier. The present disclosure also relates to battery modules or battery packs with one or more battery cells that include the multilayer thermal barrier material, as well as systems that include these battery modules or packs. [Background technology]

[0003] Rechargeable batteries, such as lithium-ion batteries, have found wide application in power-driven energy storage systems. Lithium-ion batteries (LIBs) are widely used to power portable electronic devices, such as cell phones, tablets, laptops, and power tools, and also to power other high-current devices, such as electric vehicles, due to their high operating voltage, low memory effect, and high energy density compared to conventional batteries. However, safety concerns exist because LIBs are susceptible to catastrophic failure under "severe conditions," such as when rechargeable batteries are overcharged (charged beyond their design voltage), overdischarged, operated at high temperatures and pressures, or exposed to high temperatures and pressures. As a result, the narrow operating temperature range and charge / discharge rates limit the use of LIBs, as they can fail due to rapid self-heating or thermal runaway events when exposed to conditions outside their design range.

[0004] As shown in Figure 1, the electrochemical cell of a LIB mainly consists of a positive electrode, a negative electrode, an electrolyte capable of conducting lithium ions, a separator separating the positive and negative electrodes, and a current collector. 0.8 Co 0.15 Al 0.05O2(NCA), and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NMC) are six types of cathode materials widely used in Li-ion batteries. These six types of batteries account for the majority of the current battery market share. Electrolytes consist of lithium salts dissolved in specific solvents (mainly including ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and propylene carbonate (PC)). The lithium salts are typically selected from LiClO4, LiPF6, LiBF4, LiBOB, etc. Separator materials are generally polyolefin-based resin materials. Microporous membranes of polypropylene (PP) and polyethylene (PE) are commonly used as separators in commercial lithium-ion batteries. Aluminum foil is typically used as the current collector for the positive electrode and copper foil for the negative electrode. Carbon-based materials, including hard carbon, carbon nanotubes, and graphene, are currently the primary choice for the negative electrode in most commercial lithium-ion batteries. Other novel negative electrode materials, such as titanium-based oxides, alloyed / dealloyed materials, and conversion materials, have also been investigated, which have shown good thermal and electrochemical performance.

[0005] LIB operation under normal conditions In normal operation, lithium ions move by diffusion and migration from one electrode to the other through the electrolyte and separator.

[0006] Charging a LIB causes lithium ions in the electrolyte solution to migrate from the cathode through the separator and insert themselves into the anode (Figure 2). Charge-balancing electrons also migrate to the anode, traveling through the charger's external circuit. Upon discharge, a reverse flow process occurs, with electrons flowing through the device being powered (Figure 2). During this process, heat is generated within the cell by three main mechanisms. The first mechanism is reversible heat, resulting from entropy changes associated with the redox reactions that occur during the lithiation (discharge) and delithiation (charge) processes. Reversible heat is also called entropic heat. The second mechanism is irreversible heat associated with electrode polarization caused by cell overvoltage. Finally, there is irreversible heat associated with ohmic losses, known as Joule heating. Joule heating is due to the movement of lithium ions and electrons within the cell. Under normal conditions, self-heating is very small, generally insignificant, and easily dissipated by good battery design or a battery thermal management system. However, under severe conditions, several side reactions can occur that lead to thermal runaway. Understanding the causes of thermal runaway can guide the design of functional materials to improve the safety and reliability of LIBs.

[0007] Overview of thermal runaway and thermal runaway propagation Thermal runaway can occur when the internal reaction rate increases to the point where more heat is generated than can be extracted, resulting in a further increase in both reaction rate and heat generation. During thermal runaway, high temperatures trigger a chain of exothermic reactions in the battery, causing the battery temperature to rise rapidly. Often, when thermal runaway occurs in one battery cell, the generated heat causes cells in close proximity to the cell experiencing thermal runaway to heat up quickly. Each cell added to the thermal runaway reaction traps additional energy to continue the reaction, causing thermal runaway propagation within the battery pack (Figure 3), ultimately resulting in a catastrophic accident resulting in a fire or explosion. Rapid heat dissipation and effective blocking of heat transfer paths can be effective measures to reduce the dangers posed by thermal runaway propagation.

[0008] Thermal runaway induction - severe conditions Thermal runaway can be triggered by various types of runaway, including mechanical runaway, electrical runaway, and thermal runaway (Figure 3). Each type of runaway can induce an internal short circuit (ISC) in the battery, resulting in elevated temperatures. Severe conditions can be externally or internally initiated. For example, service-induced stress, degradation, design errors (e.g., cell spacing, cell interconnection style, cell form factor, and other configuration parameters), manufacturing, operation, and maintenance are internal factors that can cause various types of runaway. External factors include damage or injury to the LIB, such as from a cell being dropped or from a cell being punctured.

[0009] Machine runaway Mechanical runaway is primarily caused by mechanical forces and typically occurs due to external factors such as severe vehicle accidents, including impact, crushing, penetration, and bending. When a battery or battery pack is impacted or caught in a collision, potential damage to the battery interior, including separator rupture and leakage of flammable electrolyte, can occur, initiating ISC and subsequently leading to thermal runaway. Destructive deformation and displacement caused by applied forces are two common characteristics of mechanical runaway. Battery pack deformation is highly likely during a vehicle collision. The layout of a battery pack installed in an electric vehicle affects the battery pack's crash response. Battery pack deformation can have dangerous effects. Battery separators can be torn, causing an internal short circuit (ISC). Flammable electrolyte leaks, potentially resulting in a fire. Penetration is another common phenomenon that can occur during a vehicle collision. Compared to crushing, when penetration is initiated, it can instantly trigger a severe ISC. Mechanical breakdown and electrical short circuiting can occur simultaneously, and the severity of the intrusion can be more severe than simple mechanical or electrical runaway.

[0010] Electrical runaway Electrical runaway mainly includes internal or external short circuit, overcharge, and overdischarge of the LIB.

[0011] Internal short circuits occur in over 90% of severe conditions. Roughly speaking, an internal short circuit occurs when the battery separator fails, causing the cathode and anode to collide with each other. Internal short circuits can occur through (1) mechanical runaway, when the separator fails by penetration or crushing, (2) electrical runaway, when the separator penetrates due to dendrite growth (Figure 4), and (3) thermal runaway, when the separator collapses at high temperatures.

[0012] An external short circuit is formed when electrodes with a voltage difference are connected by a conductor. An external short circuit in a battery pack can be caused by deformation during a car crash, water intrusion, contamination by a conductor, or electric shock during maintenance. Compared to intrusion, the heat released on the circuit of an external short circuit generally does not heat the cell. An external short circuit can cause large currents and high heat generation in the battery, which is mainly caused by heat generation according to Ohm's law. When the temperature begins to exceed approximately 70°C, the cell begins to rupture, which can result in discharge and electrolyte leakage.

[0013] Overcharging can be defined as charging a battery beyond its design voltage. Overcharging can cause a series of problems, including the deposition of Li metal on the anode, which can severely affect the electrochemical performance and safety of the battery. It can be induced by the inherent high current density and aggressive charging profile, the decomposition of the cathode material to release oxygen, and the decomposition of the organic electrolyte to release heat and gaseous products (H, hydrocarbons, CO, etc.). The overcharging process can be divided into three stages: (1) in the first stage, the voltage and temperature remain unaffected and essentially unchanged; (2) in the second stage, lithium dendrite deposition occurs on the voltage platform; and (3) in the third stage, heat and gas are generated, causing a dramatic drop in voltage and thermal runaway in the battery.

[0014] Deep discharge is another possible electrical harsh condition. Generally, voltage mismatches among multiple cells in a battery pack are inevitable. Therefore, if the battery management system is unable to monitor the voltage of any single cell, the cell with the lowest voltage will be over-discharged. The mechanism of over-discharge runaway is different from other mechanisms, and the potential danger can be underestimated. The cell with the lowest voltage in a battery pack may be forced to discharge by other cells connected in series during over-discharge. During the forced discharge, the polarity is reversed and the cell voltage becomes negative, resulting in abnormal heat generation in the over-discharged cell.

[0015] thermal runaway Thermal runaway is typically triggered by overheating. Overheating in lithium-ion batteries can occur due to mechanical runaway, electrical runaway, and connector contact loss. Generally, LIBs are stable at normal operating temperatures. However, above a certain temperature, LIB stability becomes unpredictable, and at elevated temperatures, chemical reactions within the battery case produce gases that increase internal pressure within the battery case. These gases can further react with the cathode, releasing more heat and creating temperatures within or adjacent to the battery that can ignite the electrolyte in the presence of oxygen. When the electrolyte burns, oxygen is produced, further intensifying the combustion. At some point, the increased pressure within the battery case can cause the battery case to rupture. The escaping gases can ignite and burn.

[0016] Thermal runaway caused by mechanical, electrical, and thermal stress can induce continuous heat generation, resulting in a rise in temperature inside the battery. A series of chain reactions can occur at different stages as the temperature increases. Thermal runaway follows a chain reaction mechanism, for example, of physical and / or chemical processes, during which decomposition reactions of battery component materials occur one after another (Figure 3).

[0017] Overview of the chain reaction during thermal runaway Understanding the evolution of these physical and / or chemical processes can help develop mitigation measures for thermal runaway in LIBs. LIBs can have different triggers for thermal runaway in different temperature states or regimes, including State I: low temperature (<0°C), State II: normal temperature (0–90°C), and State III: high temperature (>90°C) (Figure 5).

[0018] In State I, LIBs cannot operate efficiently at low temperatures due to a slowdown in the electrochemical reaction rate. At low temperatures, battery performance dramatically decreases as a result of a decrease in the activity of the electrode materials and the lithium ion diffusion rate in the electrolyte. The consequences of slowing down chemical reactions at low temperatures include unwanted Li deposition, plating, and dendrite growth. Dendrites are tree-like structures that can form on the lithium plating of a battery. Dendrites can rapidly penetrate the battery separator and the porous plastic membrane between the battery's anode and cathode (Figure 4). Li deposition and dendrite growth within the cell are considered to be the primary factors for inducing thermal runaway at low temperatures. Without wishing to be bound by theory, it is believed that unwanted Li deposition and dendrites can cause ISC in the battery, leading to thermal runaway.

[0019] In State II (normal-temperature operation), heat generation is minimal compared to the heat generated in the thermal runaway process. Heat generation during this operating state is primarily due to Li-ion diffusion between the solid and liquid phases, electrochemical reactions at the solid-liquid interface, and side reactions. Heat generation can cause temperature increases and temperature differences inside the battery, which can affect the life and safety of lithium-ion batteries. During State II, incipient overheating can occur as a result of at least one of the internal or external triggers mentioned above, such as overcharging the battery, exposure to excessive temperatures, an external short circuit due to incorrect wiring, or an internal short circuit due to a cell defect. When incipient overheating begins, battery operation changes from normal to abnormal as the temperature rises toward 90°C. At temperatures above 40°C, the life of a lithium-ion battery can be shortened due to accelerated side reactions, and temperatures above approximately 90°C can induce decomposition of the solid electrolyte interphase interface (SEI) film, which is defined as the onset of thermal runaway. The SEI forms on the anode of a lithium-ion battery during the first few charge cycles. The SEI provides a passivation layer on the anode surface, which prevents further electrolyte decomposition and provides the long calendar life required for many applications. The initial decomposition of the SEI is considered the first side reaction occurring during the entire thermal runaway process. The initial decomposition of the SEI occurs between 80 and 120 °C, with a peak at approximately 100 °C. The onset temperature can be lower than 80 °C, as reported by Wang et al. (Thermochim. Acta 437 (2005) 12-16), who reported that SEI decomposition can begin at temperatures as low as 57 °C.

[0020] Decomposition of SEI When stage III begins, the internal temperature rises rapidly, leading to the decomposition of the SEI film. The SEI layer is primarily composed of stable components (such as LiF and Li2CO3) and metastable components (such as polymers, ROCO2Li, (CHOCO2Li)2, and ROLi). However, the metastable components can exothermically decompose at temperatures above approximately 90°C, releasing flammable gases and oxygen. The decomposition of the SEI film is thought to initiate thermal runaway, which then triggers a series of exothermic reactions.

[0021] When decomposition of the SEI occurs, the temperature rises and the lithium metal or intercalated lithium in the anode reacts with the organic solvent in the electrolyte, releasing flammable hydrocarbon gases (ethane, methane, etc.), an exothermic reaction that further fuels the temperature rise.

[0022] Disassembly of the separator When T (temperature) is above approximately 130°C, the polyethylene (PE) / polypropylene (PP) separator begins to melt, further worsening the situation and causing a short circuit between the cathode and anode. The melting of the PE / PP separator is a thermal adsorption process, but the ISC caused by the separator melting further exacerbates the thermal runaway process.

[0023] Gas evolution and decomposition of electrolytes When T (temperature) > 180°C, the heat generated by the ISC causes decomposition of the lithium metal oxide cathode material, resulting in the release of oxygen. Cathode failure also generates higher exotherms, further increasing the temperature and pressure, resulting in further accelerated reactions. The heat buildup and gas release (oxygen and combustible gases) can then lead to combustion and explosion of the lithium-ion battery.

[0024] In the thermal runaway process, only 2% of the heat is generated by ISC, while 98% is generated by chemical reactions, including the decomposition of the SEI layer and the decomposition of the electrolyte. The largest proportion of heat generated by the rapid redox reaction between the cathode and anode is about 48%, while the heat generated by other chemical reactions in the anode, cathode, and electrolyte is much smaller. The smallest heat is generated by the decomposition of the SEI film.

[0025] The need for mitigation measures against thermal runaway Based on an understanding of the mechanisms that lead to battery thermal runaway, many approaches have been explored with the goal of reducing safety hazards through rational design of battery components. To prevent such cascading thermal runaway events from occurring, LIBs are typically designed to either maintain a sufficiently low stored energy, utilize sufficient insulating material between cells within a battery module or pack, or insulate cells from thermal events that may occur in adjacent cells, or a combination of these. The former severely limits the amount of energy that can potentially be stored in such devices. The latter limits the effective energy density by restricting the manner in which closed cells can be installed. Effective insulation and heat dissipation measures are necessary to mitigate the possibility of thermal runaway in LIBs.

[0026] Current heat dissipation methods used for LIBs Currently, several different means are utilized to maximize energy density while taking precautions to prevent cascading thermal runaway. One approach is to incorporate sufficient insulation between cells or clusters of cells. This approach is generally considered desirable for safety reasons. However, the insulating material's ability to contain heat, combined with the required volume of insulation, dictates an upper limit on achievable energy density. Another approach is through the use of phase-change materials. These materials undergo an endothermic phase change upon reaching a certain elevated temperature. The endothermic phase change absorbs some of the heat being generated, thus cooling the localized area. Typically, for electrical storage devices, these phase-change materials rely on hydrocarbon materials such as waxes and fatty acids. While these systems are effective at cooling, they are themselves flammable and therefore not useful for preventing thermal runaway if an ignition occurs within the storage device. The incorporation of expansive materials is another measure to prevent cascading thermal runaway. These materials expand above a specified temperature, forming a carbide that is designed to be lightweight and provide thermal insulation when needed. While these materials can be effective in providing insulating benefits, the expansion of the material must be considered in the design of the storage device.

[0027] The need for novel thermal barriers to meet the mechanical demands of LIB systems The expansion of the anode and cathode during charge and discharge can result in dimensional changes in the cell. For example, silicon typically undergoes up to a 300% volume change during intercalation, and graphite undergoes a volume expansion of approximately 10%. This change has both reversible and irreversible components, the magnitude of which depends on the exact cell chemistry. Reversible changes in cell thickness depend only on the cell's state of charge (SOC) and can result in thickness increases of more than 2%. Irreversible cell expansion is associated with increased pressure inside the cell and is caused by the formation of the SEI. The largest contributor to this change occurs during the first charge cycle, when the SEI first forms, but expansion continues throughout the cell's lifetime.

[0028] While extensive research has been conducted to create new materials with favorable thermal properties to prevent thermal runaway problems, the mechanical properties of these materials have not received much attention, despite their importance. For example, effective thermal barriers used between cells in a battery module or pack are needed that can provide resistance to compressive deformation to accommodate the continued expansion of the cells over their lifetime. In addition, during the initial assembly of a battery module, relatively low loads of 1 MPa or less are typically applied to the materials between the cells. When cells within a battery module or pack expand or swell during charge / discharge cycles, loads of up to approximately 5 MPa can be applied to the materials between the cells. Therefore, the compressibility, compressive resiliency, and compliance of materials, such as thermal barriers between cells, are important properties.

[0029] Insulation sheets with excellent compression properties can be useful in addressing these needs, for example, as separators between battery cells in a battery module. However, while insulation sheets between battery cells can address direct heat transfer between the battery cells, they may not address the containment or direction of hot gases and other materials. Conventional insulation sheets generally do not extend beyond the edges of the battery cells and / or the walls of the module. If the insulation sheet extends to the wall, it does not contact the wall to provide a seal or barrier. As a result, hot gases and other materials emitted from the battery cells can pass around the edges of the insulation sheet and transfer heat to other battery cells in the module. Therefore, there is a need for insulation sheets that can block the transfer of hot gases and particulate matter ("ejecta") from one cell to another by containing or redirecting these materials.

[0030] Conventional types of insulation, such as foam or fiber sheets, can withstand high temperatures but have relatively low insulating or heat containment capabilities. For such materials, the thickness of the insulation must be increased to provide effective thermal management. However, the spatial requirements of a battery module limit the size of the module as well as the spacing between cells within the module. Similarly, it is desirable to limit the overall weight of a battery module. Furthermore, there are mechanical requirements necessary to accommodate the expansion and contraction of battery cells during charge / discharge cycles and over the life of the cells. Therefore, it is necessary to minimize the thickness and weight of the material used to achieve resistance to heat and fire spread while simultaneously providing the necessary compressive and resilient properties and thermal characteristics. Furthermore, when sheet insulation materials are used, it can be difficult to achieve the manufacturing tolerances required to provide separator sheets that extend to the sidewalls of the module, especially when encapsulation is required to contain the separator sheets. Different types of insulation systems, materials, and methods are needed to provide effective insulation, heat and gas containment, and fire spread protection. Summary of the Invention

[0031] It is an object of the present disclosure to obviate or mitigate at least one disadvantage of the aforementioned methods and materials described above for preventing or mitigating thermal runaway in rechargeable batteries, such as lithium-ion batteries.

[0032] In particular, it is an object of the present disclosure to provide a multilayer material for use as a thermal barrier in electrical energy storage systems to solve the problem of heat propagation in battery modules or battery packs, and to stop or mitigate heat propagation when one cell causes thermal runaway. The unique configuration of the multilayer material of the present disclosure can help solve the problem of heat propagation between cells.

[0033] Mitigation measures can be effective at the material level, cell level, and system level to ensure the overall safety of energy storage systems that use rechargeable batteries, such as lithium-ion batteries. The multilayer material according to the present disclosure can perform at least one of the following mitigation steps: (1) reduce the likelihood of a harsh condition, (2) eliminate the harsh condition at the time a runaway occurs, (3) increase the thermal stability of battery cells that come into contact with the harsh condition, (4) reduce the energy released under normal operating conditions and in the event of a thermal runaway, and (5) reduce the risk of propagation and limit damage to a limited area.

[0034] Another object of the present disclosure is to provide a battery module or battery pack including the multilayer material according to the present invention, which can protect the battery pack from heat damage due to thermal runaway of one cell and ensure a safe design of the battery pack or battery module.

[0035] In one general aspect, the present disclosure provides novel multilayer materials comprising aerogel compositions, e.g., reinforced aerogel compositions. The aerogel compositions are durable, easy to handle, and minimize the thickness and weight of the materials used while providing favorable resistance to heat and fire propagation, as well as favorable properties related to compressibility, compressive resilience, and compliance. For example, multilayer materials according to embodiments disclosed herein can include at least one insulating layer comprising an aerogel composition or a reinforced aerogel composition.

[0036] In one general aspect, the multilayer materials disclosed herein are useful for separating, insulating, and protecting battery cells or battery components of any configuration of battery, e.g., pouch cells, cylindrical cells, prismatic cells, as well as packs and modules incorporating or containing any such cells. The multilayer materials disclosed herein are useful in rechargeable batteries, e.g., lithium ion batteries, solid-state batteries, and any other energy storage device or technology requiring separation, insulation, and protection.

[0037] In one general aspect, the present disclosure aims to provide a battery module and a battery pack that can be used to simultaneously improve the heat dissipation and thermal runaway protection capabilities of a power battery. In power-driven energy storage systems, it is common for several cells to be packed together in a preselected configuration (e.g., in parallel, in series, or in combination) to form a battery module. Several such battery modules can be further combined or joined to form various battery packs known in the art. During operation and discharge, such cells, battery modules, or battery packs typically generate or produce heat that can significantly and adversely affect the resulting performance. Therefore, in order to maintain desired or optimal performance by such cells or the resulting battery module or battery pack, it is generally important to maintain the temperature of such cells, battery modules, or battery packs within a fairly narrow, specified range. A goal of the present disclosure is to maintain the temperature of such cells, battery modules, or battery packs within an optimal range.

[0038] In addition to maintaining the cell temperature within a specified range, there is also the objective of maintaining the structural integrity of the cell. Materials within the cell need to be both flexible and resilient to accommodate volume changes during battery operation. In some embodiments, materials need to be flame or fire resistant to maintain structural integrity after or during a thermal event.

[0039] In one aspect, a multilayer material provided herein for use as a thermal barrier in an electrical energy storage system includes a core portion including a layered assemblage of at least one insulating layer and at least one heat capacity layer stacked alternatingly in a direction perpendicular to its largest surface, and an exterior portion disposed outside the core portion, the exterior portion including at least one sacrificial material layer including a compressible pad having a compressive force deflection of 25% at about 27 kPa to about 55 kPa, and at least one encapsulating material layer selected from a polymer, an elastomer, or a combination thereof.

[0040] In another aspect, a multilayer material provided herein for use as a thermal barrier in an electrical energy storage system includes a core portion including a layered assemblage of at least one insulating layer and at least one thermally conductive layer stacked alternatingly in a direction perpendicular to its largest surface, and an exterior portion disposed outside the core portion, the exterior portion including at least one sacrificial material layer having a compressive force deflection of 25% at about 27 kPa to about 55 kPa, and at least one encapsulating material layer selected from a polymer, an elastomer, or a combination thereof.

[0041] In one aspect, a multilayer material provided herein for use as a thermal barrier in an electrical energy storage system includes a core including at least one insulating layer; an exterior disposed outside the core, the exterior including at least one sacrificial material layer including a compressible pad having a compressibility modulus of about 1 MPa to about 12 MPa; and at least one encapsulating material layer selected from a polymer, an elastomer, or a combination thereof, the encapsulating material layer sandwiched between the core and the exterior sacrificial material layer. In some embodiments, the core further includes at least one heat capacity layer having a specific heat capacity of at least about 200 J / (kg·K). In some embodiments, the core includes a layered assembly of at least one insulating layer and at least one heat capacity layer alternately stacked in a direction perpendicular to its largest surface. In some embodiments, the core further includes at least one thermally conductive layer having a thermal conductivity of at least about 200 mW / m·K along an in-plane dimension of the thermally conductive layer. In some embodiments, the core comprises a layered set of at least one insulating layer and at least one thermally conductive layer that are stacked alternately in a direction perpendicular to its largest surface.

[0042] In another aspect, a multilayer material provided herein for use as a thermal barrier in an electrical energy storage system includes a core layer having two sides including at least one compressible material layer having a compressibility modulus of about 1 MPa to about 12 MPa, and optionally at least one thermally conductive layer and / or at least one heat capacity layer; and two insulating layers having a thermal conductivity through a thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C, wherein the core layer is sandwiched between the two insulating layers, the optional at least one thermally conductive layer has an in-plane thermal conductivity of at least about 200 mW / m·K, and the optional at least one heat capacity layer has a specific heat capacity of at least about 200 J / (kg·K), and the multilayer material is optionally encapsulated in an encapsulating material selected from at least one of a polymer, an elastomer, or a combination thereof. In some embodiments, the core layer further includes a flame-retardant layer. In some embodiments, the core layer lacks an optional at least one thermally conductive layer and an optional at least one thermally capacitive layer. In some embodiments, the core layer includes an optional at least one thermally conductive layer and lacks an optional at least one thermally capacitive layer. In some embodiments, the core layer includes two thermally conductive layers and one compressible material layer, the compressible material layer being sandwiched between the two thermally conductive layers. In some embodiments, the core layer includes an optional at least one thermally capacitive layer and lacks an optional at least one thermally conductive layer. In some embodiments, the core layer includes two thermally conductive layers and one compressible material layer, the compressible material layer being sandwiched between the two thermally conductive layers. In some embodiments, the core layer includes one thermally capacitive layer and two compressible material layers, the heat capacitive layer being sandwiched between the two compressible material layers. In some embodiments, the multilayer material further includes two heat capacitive layers, each disposed on an outer surface of a respective insulating layer.

[0043] Embodiments of any of the above aspects may include one or more of the following features. For example, in some embodiments, the encapsulating material layer is sandwiched between the core and the sacrificial material layer. In some embodiments, the sacrificial material layer is sandwiched between the core and the encapsulating material layer. In some embodiments, the sacrificial material layer comprises a material selected from the group consisting of siloxane, polyolefin, polyurethane, phenolic, melamine, cellulose acetate, and polystyrene. In some embodiments, the sacrificial material layer is in the form of a foam. In one or more embodiments, the onset temperature of chemical decomposition of the sacrificial material layer is in the range of about 200°C to about 400°C.

[0044] In some embodiments, the exterior further comprises a layer made from a material selected from the group of an abrasion resistant material, an intumescent material, a fire retardant material, a non-flammable material, or a combination thereof.

[0045] In some embodiments, the heat capacity layer has a specific heat capacity of at least about 200 J / (kg·K). In some embodiments, the heat capacity layer is a phase change material. In some embodiments, the heat capacity layer comprises stainless steel.

[0046] In some embodiments, the encapsulant layer is a polyethylene terephthalate layer.

[0047] In some embodiments, the encapsulation material layer further comprises a metal layer disposed between the encapsulation layer and the core.

[0048] In some embodiments, the insulating layer has a thermal conductivity through the thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C. In some embodiments, the insulating layer comprises an aerogel. In some embodiments, the insulating layer further comprises a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. In some embodiments, the insulating layer is devoid of aerogel and the insulating layer further comprises a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof.

[0049] In some embodiments, the thermally conductive layer comprises a thermally conductive layer having a thermal conductivity of at least about 200 mW / m·K along an in-plane dimension of the thermally conductive layer. In some embodiments, the thermally conductive layer comprises at least one layer comprising a metal, carbon, a conductive polymer, or a combination thereof. In some embodiments, the thermally conductive layer is a phase change material. In some embodiments, the thermally conductive layer is a metal selected from aluminum, copper, and steel. In some embodiments, the thermally conductive layer conducts heat away from a localized thermal load, preferably to an environment. In some embodiments, the thermally conductive layer is in a form selected from the group consisting of a mesh, a sheet, a perforated sheet, a foil, and a perforated foil. In some embodiments, the thermal conductivity across the thickness dimension of the insulating layer, e.g., an aerogel, at 25°C remains the same or increases by a small amount when subjected to a load of up to about 5 MPa. In some embodiments, the thermal conductivity across the thickness dimension of the insulating layer increases by less than about 50 mW / m·K at 25°C when subjected to a load of up to about 5 MPa. In some embodiments, the thermally conductive layer comprises aluminum.

[0050] In some embodiments, the insulating layer comprising aerogel further comprises a reinforcing material. In some embodiments, the reinforcing material is a fiber selected from organic polymer-based fibers, inorganic fibers, carbon-based fibers, or combinations thereof. In some embodiments, the fiber is in the form of discrete fibers, woven materials, dry-laid nonwoven materials, wet-laid nonwoven materials, needle-punched nonwovens, batting, webs, mats, felts, and / or combinations thereof. In some embodiments, the inorganic fibers are selected from glass fibers, rock fibers, metal fibers, boron fibers, ceramic fibers, basalt fibers, or combinations thereof. In one or more embodiments, the aerogel comprises a silica-based aerogel. In one or more embodiments, the aerogel comprises one or more additives, the additives being present at a level of at least about 5-40 weight percent of the aerogel, preferably at a level of at least about 5-20 weight percent of the aerogel, and more preferably at a level of at least about 10-20 weight percent of the aerogel. In some embodiments, the one or more additives comprise a fire-rated additive. In some embodiments, the one or more additives comprise an opacifying agent selected from BC, diatomaceous earth, manganese ferrite, MnO, NiO, SnO, AgO, BiO, TiC, WC, carbon black, titanium dioxide, iron-titanium oxide, zirconium silicate, zirconium oxide, iron(I) oxide, iron(III) oxide, manganese dioxide, iron-titanium oxide (ilmenite), chromium oxide, or mixtures thereof. In some embodiments, the one or more additives comprise an opacifying agent comprising silicon carbide. In some embodiments, the one or more additives comprise a combination of a fire-rated additive and an opacifying agent. In one or more embodiments, the aerogel has a density ranging from about 0.25 g / cc to about 1.0 g / cc. In some embodiments, the aerogel has a flexural modulus of about 2 MPa to about 8 MPa. In some embodiments, the aerogel provides a set compression at about 70°C ranging from about 10% to about 25%. In some embodiments, the aerogel exhibits a compression resistance of about 40 kPa to about 180 kPa at 25% strain. In one or more embodiments, the aerogel is in the form of a monolith, beads, particles, granules, powder, thin film, sheet, or combinations thereof.

[0051] In some embodiments, the thermally conductive layer includes at least one layer comprising a metal, carbon, a conductive polymer, or a combination thereof. In some embodiments, the thermally conductive layer is a phase change material. In some embodiments, the thermally conductive layer is a metal selected from aluminum, copper, and steel. In some embodiments, the thermally conductive layer conducts heat away from a localized thermal load, preferably to an environment. In some embodiments, the thermally conductive layer is in a form selected from the group consisting of a mesh, a sheet, a perforated sheet, a foil, and a perforated foil. In some embodiments, the thermal conductivity across the thickness of the insulating layer, e.g., an aerogel, at 25°C remains the same or increases by a small amount when subjected to a load of up to about 5 MPa. In some embodiments, the thermal conductivity across the thickness of the insulating layer is less than about 50 mW / m·K at 25°C when subjected to a load of up to about 5 MPa.

[0052] In one aspect, provided herein is the use of a multilayer material according to various embodiments of any of the above aspects in a battery pack including a plurality of single battery cells or groups of battery cells to thermally isolate the single battery cells or groups of battery cells from one another. In some embodiments, a runaway event occurring in one or more battery cells or groups of battery cells in a portion of the battery does not result in damage to the battery cells or groups of battery cells in the portion of the battery that are separated from the portion of the battery in which the runaway event occurs by a multilayer material according to any one of the above aspects.

[0053] In another aspect, provided herein are various embodiments of any of the above aspects of a battery pack including a plurality of single battery cells or groups of battery cells for thermally isolating the single battery cells or groups of battery cells from one another, and multilayer materials according to the claims.

[0054] In one aspect, a battery module provided herein includes a first battery cell having a first surface, a second battery cell having a second surface, the second surface facing the first surface, and a multilayer material according to various embodiments of any of the above aspects disposed between the first and second surfaces. In some embodiments, the multilayer material covers at least about 80% of the surface area of ​​the opposing first and second surfaces.

[0055] In another aspect, a battery module provided herein includes at least one battery cell and a multilayer material according to various embodiments of any of the above aspects, wherein the multilayer material is disposed on a surface of the at least one battery cell or on a surface of the battery module.

[0056] In one aspect, a battery pack provided herein includes a plurality of cells and a spacer disposed between two adjacent cells or two adjacent modules, wherein the spacer includes a multilayer material according to various embodiments according to any of the aspects described above.

[0057] The battery module or battery pack according to any of the above aspects further includes a cooling system configured to remove heat from the battery pack. In some embodiments, at least one layer of the multilayer material is in thermal communication with the cooling system. In some embodiments, the thermally conductive layer is in thermal communication with the cooling system.

[0058] In another aspect, a device or vehicle provided herein comprises a battery module or battery pack according to any one of the above aspects. In some embodiments, the device is a laptop computer, a PDA, a mobile phone, a tag scanner, an audio device, a video device, a display panel, a video camera, a digital camera, a desktop computer, a military portable computer, a military telephone, a laser range finder, a digital communication device, a secret intelligence sensor, an electronically integrated garment, a night vision device, a power tool, a calculator, a radio, a remote control device, a GPS device, a handheld and portable television, a car starter, a flashlight, a sound device, a portable heating device, a portable vacuum cleaner, or a portable medical tool. In some embodiments, the vehicle is an electric car.

[0059] In one or more embodiments, the multilayer material according to any of the above aspects has an average thickness in an uncompressed state ranging from about 2 mm to about 10 mm.

[0060] The multilayer materials described herein may offer one or more advantages over existing thermal runaway mitigation solutions. The multilayer materials described herein can minimize or eliminate thermal runaway propagation in cells and assembly costs without significantly affecting the energy density of the battery module or battery pack. The multilayer materials of the present disclosure can provide favorable properties of compressibility, compressive resilience, and compliance to accommodate continued cell expansion over the cell's lifetime, while retaining favorable thermal properties under normal operating conditions and under thermal runaway conditions. The multilayer materials described herein are durable, easy to handle, and offer favorable resistance to heat and fire propagation while minimizing the thickness and weight of the materials used, as well as favorable properties of compressibility, compressive resilience, and compliance.

[0061] In another aspect, a battery module includes a housing including an interior surface, the interior surface being defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed within an interior space of the housing; and one or more spacer elements disposed between adjacent battery cells, each spacer element including at least one heat capacity layer and at least one insulating layer. Each of the spacer elements contacts the interior surface of the housing, thereby forming a thermal barrier between adjacent battery cells. In one embodiment, the two or more battery cells are oriented longitudinally between the first and second side walls and parallel to the end plates, and the spacer elements contact the bottom surface, top surface, first side wall, and second side wall to form a thermal barrier between adjacent battery cells. In one embodiment, the spacer elements are formed from a multilayer material, as described herein.

[0062] In one embodiment, each of the spacer elements contacts one or more channels formed on and / or in the inner surface. The one or more channels may protrude from one or more of the first end plate, the second end plate, the first sidewall, the second sidewall, the top plate, and the bottom plate. Alternatively, the one or more channels are recessed in one or more of the first end plate, the second end plate, the first sidewall, the second sidewall, the top plate, and the bottom plate. Each of the spacer elements contacts one or more portions of the channels that form a seal between the spacer element and the inner surface. In one embodiment, the one or more channels are substantially U-shaped with opposing sidewalls and a bottom surface. The spacer element contacts the sidewall of the U-shaped channel. A gap may exist between the spacer element and the bottom surface of the U-shaped channel to account for manufacturing variations.

[0063] In some embodiments, the one or more spacer elements and the inner surface of the housing are configured together to define a plurality of separate compartments, with one battery cell disposed in each compartment. In some embodiments, the one or more spacer elements and the inner surface of the housing are configured together to define a plurality of separate compartments, with multiple battery cells disposed in each compartment. In some embodiments, at least a portion of the housing includes one or more vent ports, the one or more vent ports fluidly coupled to one or more of the plurality of separate compartments. The one or more vent ports may be located on a sidewall or top plate of the housing that communicates with one or more of the compartments. The vent ports may be openings or pressure relief valves. In conjunction with various gas deflection elements, channels, and other components, the vent ports can be used to create gas flow management paths that can conduct hot gases and particles away from the battery cells.

[0064] In another aspect, a battery module includes a housing including an interior surface, the interior surface being defined by a first end plate and a second end plate extending between a first side wall and a second side wall and between a top plate and a bottom plate; two or more battery cells disposed within an interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each spacer element including at least one heat capacity layer and at least one insulating layer; and one or more spacer elements disposed along the interior surface of the housing. and edge elements of at least about 100° C., wherein the edge elements are compressible and comprise a material having an onset temperature of chemical decomposition of about 100° C. or greater, about 130° C. or greater, about 200° C. or greater, about 230° C. or greater, about 240° C. or greater, about 330° C. or greater, 350° C. or greater, about 400° C. or greater, about 415° C. or greater, about 425° C. or greater, about 450° C. or greater, about 500° C. or greater, about 550° C. or greater, about 600° C. or greater, about 650° C. or greater, about 700° C. or greater, about 750° C. or greater, about 800° C. or greater, or a range between any two of these values. Each of the spacer elements contacts at least one or more of the separate edge elements, thereby forming a seal by the edge elements between the spacer elements and the inner surface of the housing that thermally isolates adjacent battery cells. In some embodiments, the two or more battery cells are oriented parallel to the end plate between the first and second side walls, the spacer element contacts the bottom surface, and one of the one or more edge elements is disposed between the spacer element and the top surface. In one embodiment, one of the one or more edge elements is disposed between the first side wall and the spacer element and / or the second side wall and the spacer element.

[0065] In some embodiments, the edge element comprises an expansion material. In other embodiments, the edge element comprises a shape memory material. In other embodiments, the edge element comprises a combination of an expansion material and a shape memory material. In other embodiments, the edge element comprises a silicone polymer. In other embodiments, the edge element comprises a multi-layer material having one or more capacitive layers and one or more insulating layers. Multi-layer materials can be used as edge elements as described herein.

[0066] In some embodiments, the one or more spacer elements, edge elements, and inner surface of the housing are configured together to define a plurality of separate compartments, with one battery cell disposed in each compartment. In some embodiments, the one or more spacer elements, edge elements, and inner surface of the housing are configured together to define a plurality of separate compartments, with multiple battery cells disposed in each compartment. In some embodiments, at least a portion of the housing includes one or more vent ports, and the one or more vent ports are fluidly coupled to one or more of the plurality of separate compartments. The one or more vent ports may be located on a sidewall or top plate of the housing that communicates with one or more of the compartments. The vent port may be an opening or a pressure relief valve.

[0067] In another aspect, a battery module includes a housing including an inner surface, the inner surface being defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed within an interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each spacer element including at least one heat capacity layer and at least one insulating layer; and one or more caps contacting the inner surface and surrounding at least a portion of one or more of the spacer elements. The one or more caps are configured to form a seal between the one or more spacer elements and the inner surface of the housing to thermally isolate adjacent battery cells. In one embodiment, the two or more battery cells are oriented parallel to the end plates and between the first and second side walls, the spacer elements contacting the bottom surface, and one of the one or more edge elements disposed between the spacer elements and the top surface. In one embodiment, one of the one or more edge elements is disposed between the first sidewall and the spacer element and / or the second sidewall and the spacer element.

[0068] In some embodiments, one or more of the caps are formed from a polymer. The polymer comprises a material having an onset temperature of chemical decomposition of about 100°C or higher, about 130°C or higher, about 200°C or higher, about 230°C or higher, about 240°C or higher, about 330°C or higher, 350°C or higher, about 400°C or higher, about 415°C or higher, about 425°C or higher, about 450°C or higher, about 500°C or higher, about 550°C or higher, about 600°C or higher, about 650°C or higher, about 700°C or higher, about 750°C or higher, about 800°C or higher, or a range between any two of these values. In some embodiments, a space is defined within one or more of the caps that can receive one of the one or more spacer elements. At least one of the one or more caps can be configured such that, during use, a gap exists between a spacer element disposed therein and an inner wall of the cap. In some embodiments, at least one of the one or more caps has a substantially U-shaped opening extending along a first longitudinal side of the cap, and one or more spacer elements fit within the U-shaped opening. In some embodiments, at least one of the one or more caps has an outer surface shaped to complement a portion of the inner surface of the housing. In some embodiments, at least one of the one or more caps has an opening at an end of the cap, the opening configured to allow the cap to slide over one of the one or more spacer elements. In some embodiments, at least one of the one or more caps completely covers an end of one of the one or more spacer elements. In some embodiments, at least one of the one or more caps has a bottom surface that contacts the bottom plate of the housing and a top surface that contacts the top plate of the housing. In some embodiments, at least one of the caps has a second longitudinal side that contacts a first sidewall or a second sidewall of the inner surface of the housing.

[0069] In some embodiments, at least one of the one or more caps contacts a channel formed in the first sidewall or the second sidewall. In one embodiment, the channel is a recess in the first sidewall and / or the second sidewall. In another embodiment, the one or more channels protrude from the first sidewall and / or the second sidewall. In some embodiments, at least one of the one or more caps contacts one or more portions of the channel and forms a seal between the cap and the inner surface. The one or more channels on the inner surface can be substantially U-shaped with opposing sidewalls and a bottom surface. In one embodiment, the cap contacts the sidewall of the U-shaped channel. In some embodiments, a gap exists between the cap and the bottom surface of the U-shaped channel.

[0070] In some embodiments, the one or more spacer elements, the cap, and the inner surface of the housing are configured together to define a plurality of separate compartments, with one battery cell disposed in each compartment. In some embodiments, the one or more spacer elements, the cap, and the inner surface of the housing are configured together to define a plurality of separate compartments, with multiple battery cells disposed in each compartment. In some embodiments, at least a portion of the housing includes one or more vent ports, and the one or more vent ports are fluidly coupled to one or more of the multiple separate compartments. The one or more vent ports may be located on a sidewall or top plate of the housing that communicates with one or more of the compartments. The vent port may be an opening or a pressure relief valve.

[0071] In another aspect, a battery module provided herein includes a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer; and one or more extensions extending from the one or more spacer elements, the one or more extensions being formed from a thermally active material, wherein the one or more extensions deflect to form a seal between the spacer elements and the housing.

[0072] In some embodiments, the thermally active material includes a shape memory material, such as a shape memory alloy (e.g., an Al-Cu-Ni alloy or a Ni-Ti alloy). In some embodiments, the thermally active material includes an expansion material. And, in some embodiments, the thermally active material includes a combination of a shape memory material and an expansion material. In some embodiments, when activated by heat (e.g., when one or more extensions deflect), the one or more deflectable extensions create a region within the battery module that is sealed from the remainder of the battery module (e.g., an area outside of seal area AA). In some embodiments, the one or more extensions include a first extension and a second extension, where the first extension deflects in an opposite orientation to the second extension.

[0073] In another aspect, a battery module provided herein includes a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer; and one or more extensions extending from the interior surface of the housing, the one or more extensions formed from a thermally active material, wherein the one or more extensions deflect to form a seal between the spacer elements and the housing.

[0074] In some embodiments, the thermally active material is a shape memory material, such as a Ni-Ti alloy. In some embodiments, the thermally active material is a combination of a shape memory material and an expansion material. For example, there is an element having a base formed from an expansion material and an attached layer or cap formed from a shape memory material. In some embodiments, one or more spacer elements include an aerogel (e.g., at least one insulating layer is formed from an aerogel). In some embodiments, one or more spacer elements can include an expansion material. For example, one or more spacer elements can be formed from an expansion material. In some embodiments, one or more spacer elements include an expansion material together with an aerogel.

[0075] In another aspect, a battery module provided herein includes a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; and one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer in physical contact with at least one thermally conductive layer including a shape memory material, wherein the shape memory material of the at least one conductive layer deflects in response to thermal activation to form a gap between the one or more spacer elements and at least one of the two or more battery cells.

[0076] In some embodiments, the shape memory material is nitinol. In some embodiments, the shape memory material is in the form of a plate. In other embodiments, the shape memory material is dispersed throughout at least one thermally conductive layer. When activated by heating, in some embodiments, the dispersed shape memory material is in an expanded spring form. Some embodiments of this aspect further include a cooling system in thermal contact with the two or more battery cells. The cooling system may include a cooling plate.

[0077] In another aspect, a device or vehicle provided herein comprises a battery module according to any one of the above aspects. In some embodiments, the device is a laptop computer, a PDA, a mobile phone, a tag scanner, an audio device, a video device, a display panel, a video camera, a digital camera, a desktop computer, a military portable computer, a military telephone, a laser range finder, a digital communication device, a secret intelligence sensor, an electronically integrated garment, a night vision device, a power tool, a calculator, a radio, a remote control device, a GPS device, a handheld and portable television, a car starter, a flashlight, a sound device, a portable heating device, a portable vacuum cleaner, or a portable medical tool. In some embodiments, the vehicle is an electric car.

[0078] The disclosure is therefore described in general terms and reference is now made to the accompanying drawings, which are not necessarily drawn to scale. [Brief explanation of the drawings]

[0079] [Figure 1] FIG. 1 is a schematic diagram of an electrochemical cell of a Li-ion battery. [Figure 2] FIG. 1 is a schematic diagram of the charge and discharge process of a Li-ion battery. [Figure 3] 1 illustrates a schematic representation of a thermal runaway harsh condition and a thermal runaway propagation process within a battery module. [Figure 4] FIG. 1 is a schematic illustration of dendrite growth on lithium plating in a battery. [Figure 5] The three stages that lead to the thermal runaway process are shown schematically. [Figure 6] 1 shows a schematic diagram of a battery cell, a battery module, and a battery pack. [Figure 7] 1A and 1B illustrate schematic diagrams of multi-layer materials according to certain embodiments disclosed herein. [Figure 8] 1A and 1B illustrate schematic diagrams of multi-layer materials according to certain embodiments disclosed herein. [Figure 9A] 1A and 1B illustrate schematic diagrams of multilayer materials for use as thermal barriers in electrical energy storage systems, according to embodiments disclosed herein. [Figure 9B] 10A-10C schematically illustrate another multi-layer material for use as a thermal barrier in an electrical energy storage system, according to embodiments disclosed herein. [Figure 9C] 1A and 1B illustrate schematic diagrams of multilayer materials for use as thermal barriers in electrical energy storage systems, according to embodiments disclosed herein. [Figure 9D] 1A and 1B illustrate schematic diagrams of multilayer materials for use as thermal barriers in electrical energy storage systems, according to embodiments disclosed herein. [Figure 9E] 1A and 1B illustrate schematic diagrams of multilayer materials for use as thermal barriers in electrical energy storage systems, according to embodiments disclosed herein. [Figure 10] FIG. 1 is a diagram of a prior art battery module. [Figure 11A]FIG. 1 is a diagram of a battery module having extending spacer elements. [Figure 11B] FIG. 1 is a side view of a battery module having extending spacer elements. [Figure 12A] FIG. 10 is a diagram of a battery module having spacer elements positioned in protruding channels. [Figure 12B] FIG. 10 is a diagram of a battery module having spacer elements positioned in recessed channels. [Figure 13] FIG. 1 is a view of the top plate of the battery module. [Figure 14] FIG. 10 is a diagram of a battery module having edge elements that form a seal between the spacer elements and the housing. [Figure 15] FIG. 10 is a close-up view of the interface between the spacer element and the edge element. [Figure 16] FIG. 10 is a close-up view of the interface between the spacer element and the cap. [Figure 17] 10A-10C are diagrams of alternative configurations of battery modules with spacer elements positioned in the caps. [Figure 18A] 1 illustrates an embodiment of a spacer element having an extended heat capacity or heat conduction layer sandwiched between insulating layers within a battery module. [Figure 18B] 18B shows the spacer element of FIG. 18A in use. [Figure 19A] 10 illustrates an embodiment of a spacer element having an extension within a battery module. [Figure 19B] 19B shows the spacer element of FIG. 19A in use. [Figure 20A] 10 shows an alternative embodiment of a spacer element having an extension. [Figure 20B] 20B shows the spacer element of FIG. 20A in use. [Figure 21A] 10 illustrates a modification of the extension that can be applied to any of the embodiments disclosed herein. [Figure 21B] 21B shows the extension of FIG. 21A in use. [Figure 22]10 illustrates an embodiment of a spacer element that includes a layer that extends beyond the dimensions of the battery cell relative to the housing. [Figure 23] 1 illustrates an embodiment of a spacer element, or a portion of a spacer element, that can cover one battery cell and at least partially isolate it from the other battery cell. [Figure 24] 10 shows an embodiment in which separate edge elements are positioned along the housing wall at locations proximate to the expected locations of the spacer elements. [Figure 25A] 10 illustrates an embodiment of an edge element used to form a seal between a spacer element and the interior of a housing prior to positioning of the spacer element. [Figure 25B] The edge elements of Figure 25A are shown after positioning of the spacer elements. [Figure 26] Figure 26A is a diagram of a battery module with shape memory edge elements and expanding edge elements before a heating triggering event, Figure 26B is a diagram of the battery module of Figure 26A after a heating triggering event, Figure 26C is a diagram of a battery module with shape memory elements before a heating triggering event, and Figure 26D is a diagram of the battery module of Figure 26C after a heating triggering event. [Figure 27] Figure 27A is a diagram of a battery module having spacer / shape elements formed from a combination of shape memory material and expansion material before a heating triggering event, Figure 27B is a diagram of the battery module of Figure 27A after a heating triggering event, Figure 27C is a diagram of a battery module having shape memory edge elements and expansion spacer elements before a heating triggering event, and Figure 27D is a diagram of the battery module of Figure 27C after a heating triggering event. [Figure 28A] 1 is a diagram of a portion of a battery module including a shape memory plate sandwiched between a battery cell and a thermal barrier layer prior to a heating-inducing event. [Figure 28B] FIG. 28B is a view of a portion of the battery module of FIG. 28A after a heating-inducing event. [Figure 29A] 1 is a diagram of a portion of a battery module including a thermally conductive layer including shape memory material elements dispersed throughout the thermally conductive layer prior to a heating triggering event. [Figure 29B] FIG. 29B is a view of a portion of the battery module of FIG. 29A after a heating-induced event. [Figure 29C] FIG. 10 shows a top view of a thermally conductive layer with shape memory material elements dispersed throughout. DETAILED DESCRIPTION OF THE INVENTION

[0080] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the present disclosure may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure.

[0081] The present disclosure is directed to multilayer materials and systems for managing thermal runaway issues in energy storage systems. Exemplary embodiments include multilayer materials including at least one insulating layer, at least one compressible pad, and one or more optional layers. The optional one or more layers have favorable heat dissipation properties, favorable fire resistance, flame retardancy, and / or abrasion resistance properties, and favorable performance for use as a thermal barrier. The present disclosure also relates to battery modules or battery packs with one or more battery cells and a multilayer thermal barrier material disposed in thermal communication with the battery cells.

[0082] One or more of the insulating layers of the multilayer materials disclosed herein may comprise an aerogel composition or a reinforced aerogel composition. Aerogel materials are known to possess thermal resistance approximately two to six times greater than other common types of insulation, such as foams and fiberglass. Aerogels can substantially improve the effective shielding and thermal insulation without increasing the thickness or adding additional weight of the insulation. Aerogels are known to be a structural class with low density, open-cell structure, large surface area, and nanometer-scale pore size.

[0083] Multilayer materials according to embodiments of the present disclosure, and multilayer materials including aerogel compositions, offer favorable properties related to compressibility, compressive resiliency, and compliance. When used as a thermal barrier between cells in a battery module, the multilayer materials can provide resistance to compressive deformation to accommodate cell expansion due to degradation and expansion of the active materials during battery charge / discharge cycling.

[0084] The present disclosure also provides a battery module or battery pack including at least one battery cell according to an embodiment disclosed herein and a multilayer material disposed on the battery cell or battery module, e.g., disposed on a surface of at least one battery cell or on a surface of the battery module. For example, the battery module or battery pack has an interior surface and an exterior surface. In certain embodiments, the multilayer material is on the interior surface of the battery module or battery pack. In certain embodiments, the multilayer material is on the exterior surface of the battery module or battery pack.

[0085] The multilayer materials of the present disclosure may have a variety of unique configurations in which two or more layers having favorable thermal and / or mechanical properties are arranged in a specific manner. Figure 7 illustrates a multilayer material 400 according to an embodiment disclosed herein. In one embodiment, the multilayer material 400 for use as a thermal barrier in an electrical energy storage system includes a core portion 700 and an outer portion 600, wherein the core portion 700 includes a layered assembly of at least one insulating layer 470 and / or 480 and at least one heat capacity layer 430, 440, and / or 450, the insulating layers and heat capacity layers being stacked alternately in a direction perpendicular to their largest surfaces, and the outer portion 600 is disposed outside the core portion 700, and the outer portion 600 has a compressive modulus of about 1 MPa to about 12 MPa. and at least one encapsulating material layer 420 selected from a polymer, an elastomer, or a combination thereof, wherein the heat capacity layers 430, 440, and / or 450 have a specific heat capacity of at least about 200 J / (kg·K), and the insulating layers 470 and / or 480 have a thermal conductivity through the thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C.

[0086] In some embodiments, insulating layers 470 and 480 are made from the same material. In some embodiments, insulating layers 470 and 480 are made from different materials having different thermal and / or mechanical properties. In some embodiments, heat capacity layers 430, 440, and 450 are made from the same material. In some embodiments, heat capacity layers 430, 440, and 450 are made from different materials having different thermal and / or mechanical properties. Additionally, compressible pads 410 and 460 can be made from different materials or the same material.

[0087] 8 illustrates a multilayer material 500 according to embodiments disclosed herein. In one embodiment, a multilayer material 400 for use as a thermal barrier in an electrical energy storage system includes a core portion 700 and an outer portion 600, wherein the core portion 700 includes a layered assembly of at least one insulating layer 470 and / or 480 and at least one thermally conductive layer 530, 540, and / or 550, the insulating layers and thermally conductive layers being stacked alternately in a direction perpendicular to their largest surfaces, and the outer portion 600 is disposed outside the core portion 700, and the outer portion 600 is a compressible material having a compressibility modulus of about 1 MPa to about 12 MPa. and at least one encapsulating material layer 420 selected from a polymer, an elastomer, or a combination thereof, wherein the thermally conductive layers 530, 540, and / or 550 have a thermal conductivity along an in-plane dimension of the thermally conductive layer of at least about 200 mW / m·K, and the insulating layers 470 and / or 480 have a thermal conductivity through a thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C.

[0088] In some embodiments, thermally conductive layers 530, 540, and 550 are made from the same material. In some embodiments, thermally conductive layers 530, 540, and 550 are made from different materials having different thermal and / or mechanical properties.

[0089] 7 and 8, the encapsulating material layer 420 is sandwiched between the core portion 700 and a sacrificial material layer having at least one compressible pad 410 and / or 460. In some embodiments, the sacrificial material layer having at least one compressible pad 410 and / or 460 is sandwiched between the core portion 700 and the encapsulating material layer 420.

[0090] Multilayer materials according to embodiments disclosed herein can have an average thickness in the uncompressed state ranging from about 2 mm to about 10 mm. The average thickness of the multilayer material can decrease when exposed to an external mechanical load, e.g., up to 1 MPa, such as a load applied to the material between cells during initial assembly of a battery module.

[0091] In an exemplary configuration of the multilayer material shown in FIG. 9A , a multilayer material 800 for use as a thermal barrier in an electrical energy storage system includes a two-sided core layer with at least one compressible pad 410 and / or 460 having a compression modulus of about 1 MPa to about 12 MPa (e.g., 1.5 MPa, 2 MPa, 4 MPa, 5 MPa, 6 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 11.5 MPa), and two insulating layers 470 and 480 having a thermal conductivity through the thickness dimension of the insulating layers of less than about 50 mW / m·K at 25° C. and less than about 60 mW / m·K at 600° C., wherein the core layer is sandwiched between the two insulating layers 470 and 480, and the multilayer material is optionally encapsulated in an encapsulating material 420 selected from at least one of a polymer, an elastomer, or a combination thereof.

[0092] In an exemplary configuration of the multilayer material shown in FIG. 9B , a multilayer material 810 for use as a thermal barrier in an electrical energy storage system includes a core layer having two sides with one compressible pad 410 or 460 having a compressibility modulus of about 1 MPa to about 12 MPa, two thermally conductive layers 530, 540, and / or 550, and two insulating layers 470 and 480 having a thermal conductivity through a thickness dimension of the insulating layers of less than about 50 mW / m·K at 25° C. and less than about 60 mW / m·K at 600° C., wherein the core layer is sandwiched between the two insulating layers 470 and 480, and the at least one thermally conductive layer has an in-plane thermal conductivity of at least about 200 mW / m·K, and the multilayer material is optionally encapsulated in an encapsulating material 420 selected from at least one of a polymer, an elastomer, or a combination thereof.

[0093] In the exemplary configuration shown in FIG. 9C , a multilayer material 820 for use as a thermal barrier in an electrical energy storage system includes a core layer having two sides with one compressible pad 410 or 460 having a compressibility modulus of about 1 MPa to about 12 MPa, two thermally conductive layers 430, 440, and / or 450, and two insulating layers 470 and 480 having a thermal conductivity of less than about 50 mW / m·K at 25° C. and less than about 60 mW / m·K at 600° C. through a thickness dimension of the insulating layers, the core layer sandwiched between the two insulating layers 470 and 480, and at least one heat capacity layer having a specific heat capacity of at least about 200 J / (kg·K), the multilayer material optionally encapsulated in an encapsulating material 420 selected from at least one of a polymer, an elastomer, or a combination thereof.

[0094] In an exemplary configuration shown in FIG. 9D , a multilayer material 830 for use as a thermal barrier in an electrical energy storage system includes a core layer having two sides with one compressible pad 410 or 460 having a compressibility modulus of about 1 MPa to about 12 MPa, two heat capacity layers 430, 440, or 450, and two insulating layers 470 and 480 having a thermal conductivity of less than about 50 mW / m·K at 25° C. and less than about 60 mW / m·K at 600° C. through the thickness dimension of the insulating layer, wherein the core layer is The multi-layer material 830 is sandwiched between layer 470 and insulating layer 480, at least one heat capacity layer having a specific heat capacity of at least about 200 J / (kg·K), and the multi-layer material is optionally encapsulated in an encapsulating material 420 selected from at least one of a polymer, an elastomer, or a combination thereof, and the multi-layer material 830 further includes two heat capacity layers 430, 440, and / or 450, each of which is disposed on an outer surface of insulating layer 470 and insulating layer 480, respectively.

[0095] In an exemplary configuration of the multilayer material shown in FIG. 9E , a multilayer material 840 for use as a thermal barrier in an electrical energy storage system includes a core layer having two sides with two compressible pads 410 and 460 having a compressibility modulus of about 1 MPa to about 12 MPa, one heat capacity layer 430, 440, or 450, and two insulating layers 470 and 480 having a thermal conductivity of less than about 50 mW / m·K at 25° C. and less than about 60 mW / m·K at 600° C. through a thickness dimension of the insulating layers, the core layer being sandwiched between the two insulating layers 470 and 480, the at least one heat capacity layer having a specific heat capacity of at least about 200 J / (kg·K), the multilayer material optionally encapsulated in an encapsulating material 420 selected from at least one of a polymer, an elastomer, or a combination thereof, and the heat capacity layer being sandwiched between the two compressible pads 410 and 460.

[0096] Insulation layer The insulating layers of the multilayer materials described herein are responsible for reliably controlling heat flow from heat-generating components in small spaces, providing safety and protection against fire spread in such products in the fields of electronics, industrial technology, and automotive technology. Thermal insulation layers with excellent compressibility can be useful in addressing these needs. In many embodiments of the present disclosure, the insulating layer also functions as a flame / fire deflection layer, either by itself or in combination with other layers of the multilayer material. For example, an insulating layer, e.g., an aerogel layer combined with a non-combustible layer, such as a metal or mica layer, can provide protection for underlying layers from flame and / or hot gases, as well as from flame / hot gases entrained with particulate materials, such as materials that may be extruded from LIBs during a thermal runaway event. As another example, the insulating layer itself can be resistant to flame and / or hot gases, as well as flame / hot gases entrained with particulate materials. An insulating layer, such as mica, microporous silica, or aerogel, combined with a non-combustible layer, can function as a flame / fire deflection layer. Insulation layers comprising aerogels, such as those disclosed in embodiments herein, are durable, easy to handle, and have favorable resistance to heat and fire spread while minimizing the thickness and weight of the materials used, as well as favorable properties related to compressibility, compressive resiliency, and compliance.

[0097] Aerogels are a class of open-cell porous materials that contain an interconnected skeleton with a corresponding network of pores integrated within the skeleton, and an interstitial phase within the pore network that consists primarily of a gas, such as air. Aerogels are generally characterized by low density, high porosity, large surface area, and small pore size. Aerogels can be distinguished from other porous materials by their physical and structural properties.

[0098] Thus, in some embodiments, the insulating layer of the multilayer material of the present disclosure comprises an aerogel. In some embodiments, the insulating layer may further comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof. In some embodiments, the insulating layer lacks aerogel. In some embodiments, the insulating layer may comprise a material selected from the group consisting of mica, microporous silica, ceramic fibers, mineral wool, and combinations thereof.

[0099] In certain embodiments, an insulating layer of the present disclosure has a thermal conductivity at 25°C through the thickness dimension of the insulating layer of about 50 mW / mK or less, about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or a range between any two of these values. In certain embodiments, an insulating layer of the present disclosure has a thermal conductivity at 600°C through the thickness dimension of the insulating layer of about 60 mW / mK or less, about 50 mW / mK or less, about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or a range between any two of these values.

[0100] Insulation layers of the present disclosure, such as insulation layers comprising aerogel, can retain or increase a small amount of thermal conductivity (typically measured in mW / m·K) when subjected to a load of up to about 5 MPa. In certain embodiments, insulation layers of the present disclosure have a thermal conductivity of about 50 mW / mK or less, about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or a range between any two of these values, at 25° C. when subjected to a load of up to about 5 MPa through the thickness dimension of the insulation layer. As a result of the load experienced by the aerogel insulation layer, the thickness of the aerogel insulation layer can decrease. For example, the thickness of the aerogel insulation layer can be reduced by 50% or less, 40% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, or a range between any two of these values, when subjected to a load in the range of about 0.50 MPa to 5 MPa. As the thickness is reduced, the thermal resistance of the aerogel-containing insulation layer can decrease, but the thermal conductivity can be maintained or increased by only a small amount.

[0101] In certain embodiments, an insulation layer of the present disclosure may have a heat of combustion of about 750 cal / g or less, about 717 cal / g or less, about 700 cal / g or less, about 650 cal / g or less, about 600 cal / g or less, about 575 cal / g or less, about 550 cal / g or less, about 500 cal / g or less, about 450 cal / g or less, about 400 cal / g or less, about 350 cal / g or less, about 300 cal / g or less, about 250 cal / g or less, about 200 cal / g or less, about 150 cal / g or less, about 100 cal / g or less, about 50 cal / g or less, about 25 cal / g or less, about 10 cal / g or less, or a range between any two of these values. An insulation layer with an improved heat of combustion relative to another insulation layer has a lower heat of combustion value compared to a reference insulation layer. In certain embodiments of the present disclosure, the HOC of an insulation layer is improved by incorporating a fire-rated additive into the insulation layer.

[0102] In certain embodiments, the insulating layer of the present disclosure has an onset temperature of thermal decomposition of about 300°C or higher, about 320°C or higher, about 340°C or higher, about 360°C or higher, about 380°C or higher, about 400°C or higher, about 420°C or higher, about 440°C or higher, about 460°C or higher, about 480°C or higher, about 500°C or higher, about 515°C or higher, about 550°C or higher, about 600°C or higher, or a range between any two of these values. Within the context of this specification, for example, an improvement of a first composition over a second composition would be considered for a first composition having an onset temperature of thermal decomposition that is higher than the onset temperature of thermal decomposition of a second composition. It is contemplated herein that the addition of one or more fire-rated additives increases the onset temperature of thermal decomposition of a composition or material compared to a composition without any fire-rated additives.

[0103] The term "flexural modulus" or "flexural modulus of elasticity" is a measure of a material's stiffness / resistance to bending when a force is applied perpendicular to the long edge of the sample in what is known as a three-point bend test. Flexural modulus indicates the material's ability to bend. Flexural modulus is represented by the slope of the initial linear portion of the stress-strain curve and is calculated by dividing the change in stress by the corresponding change in strain. The ratio of stress to strain is therefore a measure of flexural modulus. The international standard unit of flexural modulus is the pascal (Pa or N / m 2 or m -l kg s -2 ) The practical units used are megapascals (MPa or N / mm²) or gigapascals (GPa or kN / mm²). 2 ) In U.S. customary units, it is expressed as pounds (force) per square inch (psi). In certain embodiments, the insulating layer of the present disclosure has a flexural modulus of about 8 MPa or less, about 7 MPa or less, about 6 MPa or less, about 5 MPa or less, about 4 MPa or less, or about 3 MPa or less. Preferably, the insulating layer of the present disclosure, e.g., aerogel, has a flexural modulus of about 2 MPa to about 8 MPa.

[0104] As explained above, the compressibility and resilience properties of the materials between the cells or between the battery modules and battery packs are important to accommodate the expansion of the cells during their life cycle. In certain embodiments, the insulating layer, or multilayer material including the insulating layer, (i) is compressible to at least 50%, preferably at least 65%, and most preferably at least 80% of its original or uncompressed thickness, and (ii) is sufficiently resilient so that after compression for several seconds, the insulating layer returns to at least 70%, preferably at least 75%, and most preferably at least 80% of its original or uncompressed thickness.

[0105] In certain embodiments, the compressibility modulus of the insulating layer (e.g., a layer comprising an aerogel), the compressible component of the multilayer material comprising the insulating layer, or the multilayer material as a whole is about 1 MPa, about 2 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa, about 11 MPa, about 12 MPa, or a range between any two of these values.

[0106] aerogel The aerogels of the present invention can be organic, inorganic, or a mixture thereof. In some embodiments, the aerogel comprises a silica-based aerogel. The insulating layer of the aerogel-containing multilayer material further comprises a reinforcing material. The reinforcing material can be any material that provides resilience, compliance, or structural stability to the aerogel material. Examples of well-known reinforcing materials include, but are not limited to, open-cell macroporous skeletal reinforcement, closed-cell macroporous skeletal reinforcement, open-cell membrane, honeycomb reinforcement, polymeric reinforcement, and fibrous reinforcement such as discrete fibers, woven materials, nonwoven materials, needle-punched nonwovens, batting, webs, mats, and felts.

[0107] The reinforcing material can be selected from organic polymer-based fibers, inorganic fibers, carbon-based fibers, or combinations thereof. The inorganic fibers can be selected from glass fibers, rock fibers, metal fibers, boron fibers, ceramic fibers, basalt fibers, or combinations thereof.

[0108] In some embodiments, the reinforcing material may include a reinforcing material that includes multiple layers of material. For example, the multiple layers of material may be bonded together. In an exemplary embodiment, at least one of the multiple layers may include a first material, and at least one other of the multiple layers may include a second material. The first and second materials may have the same or different material properties. For example, the first material may be more compressible than the second material. As another example, the first material may include closed cells, and the second material may include open cells.

[0109] Aerogels are typically described as interconnected structural frameworks composed of interconnected oligomeric, polymeric, or colloidal particles. Aerogel frameworks can be made from a variety of precursor materials, including inorganic precursor materials (such as those used to produce silica-based aerogels), organic precursor materials (such as those used to produce carbon-based aerogels), hybrid inorganic / organic precursor materials, and combinations thereof. Within the context of this disclosure, the term "amalgam aerogel" refers to an aerogel produced from a combination of two or more different gel precursors. The corresponding precursors are referred to as "amalgam precursors."

[0110] inorganic aerogel Inorganic aerogels are generally formed from metal oxide or metal alkoxide materials. The metal oxide or metal alkoxide materials can be based on the oxide or alkoxide of any metal capable of forming an oxide. Such metals include, but are not limited to, silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, cerium, etc. Inorganic silica aerogels are traditionally made by the hydrolysis and condensation of silica-based alkoxides (such as tetraethoxysilane) or by the gelation of silicic acid or water glass. Other relevant inorganic precursor materials for the synthesis of silica-based aerogels include metal silicates, including, but not limited to, sodium or potassium silicate, alkoxysilanes, partially hydrolyzed alkoxysilanes, tetraethoxysilane (TEOS), partially hydrolyzed TEOS, condensation polymers of TEOS, tetramethoxysilane (TMOS), partially hydrolyzed TMOS, condensation polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzed and / or condensation polymers of tetra-n-propoxysilane, polyethylsilicate, partially hydrolyzed polyethylsilicate, monomeric alkylalkoxysilanes, bistrialkoxyalkyl or arylsilanes, polyhedral silsesquioxanes, or combinations thereof.

[0111] In certain embodiments of the present disclosure, pre-hydrolyzed TEOS, such as Silbond H-5 (SBH5, Silbond Corp), is hydrolyzed to a water / silica ratio of about 1.9 to 2, which may be used commercially or may be further hydrolyzed before being incorporated into the gelation process. Partially hydrolyzed TEOS or TMOS, such as polyethyl silicate (Silbond 40) or polymethyl silicate, may also be used commercially or may be further hydrolyzed before being incorporated into the gelation process.

[0112] Inorganic aerogels can also include gel precursors containing at least one hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metal alkoxides, and aryl metal alkoxides, which can impart or improve certain properties of the gel, such as stability and hydrophobicity. Inorganic silica aerogels can specifically include hydrophobic precursors, such as alkyl silanes or aryl silanes. Hydrophobic gel precursors can be used as primary precursor materials to form the framework of the gel material. However, hydrophobic gel precursors are more commonly used as co-precursors in combination with simple metal alkoxides to form amalgam aerogels. Hydrophobic inorganic precursor materials for silica-based aerogel synthesis include, but are not limited to, trimethylmethoxysilane (TMS), dimethyldimethoxysilane (DMS), methyltrimethoxysilane (MTMS), trimethylethoxysilane, dimethyldiethoxysilane (DMDS), methyltriethoxysilane (MTES), ethyltriethoxysilane (ETES), diethyldiethoxysilane, dimethyldiethoxysilane (DMDES), ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane (PhTES), hexamethyldisilazane, hexaethyldisilazane, etc. Any derivative of any of the above precursors can be used; in particular, certain polymers of other chemical groups can be added to or crosslinked to one or more of the above precursors.

[0113] Aerogels can also be treated to impart or improve hydrophobicity. Hydrophobic treatments can be applied to sol-gel solutions, wet gels prior to liquid extraction, or to aerogels following liquid extraction. Hydrophobic treatments are particularly common for metal oxide aerogels, such as silica aerogels. Examples of hydrophobic treatments for gels are described in more detail below, specifically with respect to treating silica wet gels. However, the specific examples and examples provided herein are not intended to limit the scope of the present disclosure to any particular type of hydrophobic treatment or aerogel substrate. The present disclosure includes any gel or aerogel known to those skilled in the art, as well as related methods of hydrophobic treatment of aerogels, either in wet gel or dry aerogel formation.

[0114] The hydrophobic treatment is carried out by reacting hydroxy moieties on the gel, such as silanol groups (Si-OH) present on the silica gel framework, with the functional groups of the hydrophobizing agent. The resulting reaction converts the silanol groups and hydrophobizing agent into hydrophobic groups on the silica gel framework. The hydrophobizing agent compound can react with hydroxyl groups on the gel according to the following reaction: RNMX4-N (hydrophobizing agent) + MOH (silanol) → MOMRN (hydrophobic group) + HX. The hydrophobizing treatment can be carried out both on the outer macroscopic surface of the silica gel and on the inner pore surfaces within the porous network of the gel.

[0115] The gel can be immersed in a mixture of a hydrophobizing agent and an optional hydrophobic treatment solvent, in which the hydrophobizing agent is soluble and which is also miscible with the gel solvent of the wet gel. A wide range of hydrophobic treatment solvents can be used, including solvents such as methanol, ethanol, isopropanol, xylene, toluene, benzene, dimethylformamide, and hexane. Alternatively, a liquid or gaseous hydrophobizing agent can be directly contacted with the gel to render it hydrophobic.

[0116] The hydrophobic treatment process may include mixing or agitation to help the hydrophobizing agent penetrate the wet gel. The hydrophobic treatment process may also include varying other conditions, such as temperature and pH, to further enhance and optimize the treatment reaction. After the reaction is complete, the wet gel is washed to remove unreacted compounds and reaction by-products.

[0117] Hydrophobizing agents for the hydrophobic treatment of aerogels are generally compounds of the formula: RNMX4-N, where M is a metal, R is a hydrophobic group such as CH3, CH2CH3, CH6H6, or a similar hydrophobic alkyl, cycloalkyl, or aryl moiety, and X is a halogen, typically Cl. Specific examples of hydrophobizing agents include, but are not limited to, trimethylchlorosilane (TMCS), triethylchlorosilane (TECS), triphenylchlorosilane (TPCS), dimethylchlorosilane (DMCS), dimethyldichlorosilane (DMDCS), and the like. The hydrophobizing agent may also be of the formula: Y(R3M)2, where M is a metal, Y is a bridging group such as NH or O, and R is a hydrophobic group such as CH3, CH2CH3, CH6H6, or a similar hydrophobic alkyl, cycloalkyl, or aryl moiety. Specific examples of such hydrophobizing agents include, but are not limited to, hexamethyldisilazane [HMDZ] and hexamethyldisiloxane [HMDSO]. Hydrophobizing agents may further include the following compounds: RNMV4-N, where V is a reactive or leaving group other than halogen. Specific examples of such hydrophobizing agents include, but are not limited to, vinyltriethoxysilane and vinyltrimethoxysilane.

[0118] The hydrophobic treatment of the present disclosure may also be performed during liquid removal, exchange, or drying of the gel. In specific embodiments, the hydrophobic treatment may be performed in a supercritical fluid environment (such as, but not limited to, supercritical carbon dioxide) and may be combined with a drying or extraction step.

[0119] organic aerogel Organic aerogels are generally formed from carbon-based polymer precursors. Such polymeric materials include, but are not limited to, resorcinol formaldehyde (RF), polyimides, polyacrylates, polymethyl methacrylates, acrylate oligomers, polyoxyalkylenes, polyurethanes, polyphenols, polybutadians, trialkoxysilyl-terminated polydimethylsiloxanes, polystyrenes, polyacrylonitriles, polyfurfural, melamine formaldehyde, cresol formaldehyde, phenol furfural, polyethers, polyols, polyisocyanates, polyhydroxybenzenes, polyvinyl alcohol dialdehydes, polycyanurates, polyacrylamides, various epoxies, agar, agarose, chitosan, and combinations thereof. As an example, organic RF aerogels are typically made from the sol-gel polymerization of resorcinol or melamine with formaldehyde under alkaline conditions.

[0120] Organic / inorganic hybrid aerogel Organic / inorganic hybrid aerogels consist primarily of organically modified silica ("ormosil") aerogels. These ormosil materials contain organic components covalently bonded to a silica network. Ormosils are typically formed by the hydrolysis and condensation of organically modified silanes, R--Si(OX)3, with the conventional alkoxide precursor Y(OX)4. In these formulas, X can represent, for example, CH3, C2H5, C3H7, or C4H9; Y can represent, for example, Si, Ti, Zr, or Al; and R can be any organic fragment, such as methyl, ethyl, propyl, butyl, isopropyl, methacrylate, acrylate, vinyl, or epoxide. The organic components of ormosil aerogels can also be dispersed throughout or chemically bonded to the silica network.

[0121] In certain embodiments, the aerogels of the present disclosure are inorganic silica aerogels formed primarily from prepolymerized silica precursors, such as oligomers, or hydrolyzed silicate esters formed from silicon alkoxides in alcohol solvents. In certain embodiments, such prepolymerized silica precursors or hydrolyzed silicate esters may be formed in situ from other precursors or silicate esters, such as alkoxysilanes or waterglass. However, the present disclosure as a whole may be practiced with any other aerogel compositions known to those skilled in the art and is not limited to any one precursor material or amalgamated mixture of precursor materials.

[0122] Macropores As explained above, aerogel compositions according to embodiments of the present disclosure may include an aerogel skeleton containing macropores. Without being bound to any particular theory of operation, the presence of macropores within the aerogel skeleton may allow for compression of the aerogel composition, e.g., a reinforced aerogel composition, while maintaining or even improving thermal properties, e.g., reducing thermal conductivity. For example, the macropores may deform, shatter, or otherwise reduce in size upon compression of the composition, thereby allowing the thickness of the composition to be reduced when subjected to a load. However, as the macropores deform, they effectively become smaller pores. As a result, as the macropores deform, the pathways for heat transfer within the aerogel skeleton may become more tortuous, thereby improving thermal properties, e.g., reducing thermal conductivity. Within the context of the present disclosure, "mesopores" are pores with an average pore diameter ranging from about 2 nm to about 50 nm. Aerogel skeletons are generally mesoporous (i.e., primarily containing pores with average diameters ranging from about 2 nm to about 50 nm). In certain embodiments, the aerogel skeleton of the aerogel compositions of the present disclosure can contain macropores. Within the context of this disclosure, "macropores" are pores having an average pore diameter greater than about 50 nm. The aerogel skeleton can contain both macropores and mesopores. For example, at least 10% of the pore volume of the aerogel skeleton can be composed of macropores, at least 5% of the pore volume of the aerogel skeleton can be composed of macropores, at least 75% of the pore volume of the aerogel skeleton can be composed of macropores, at least 95% of the pore volume of the aerogel skeleton can be composed of macropores, or 100% of the pore volume of the aerogel skeleton can be composed of macropores. In some specific embodiments, the aerogel skeleton can be a macroporous aerogel skeleton, such that a majority of its pore volume is composed of macropores. In some cases, the macroporous aerogel skeleton can also contain micropores and / or mesopores. In some embodiments, the average pore size (diameter) of the pores in the aerogel framework is greater than 50 nm, and can be 50 nm to 5000 nm, 250 nm to 2000 nm, 500 nm to 2000 nm, 500 nm to 1400 nm, or 1200 nm.In certain embodiments, the average pore size diameter may be greater than 50 nm, between 50 nm and 1000 nm, preferably between 100 nm and 800 nm, and more preferably between 250 nm and 750 nm.

[0123] Homogeneous and heterogeneous pore size distribution In some embodiments, the variation in pore size within the aerogel framework can be homogeneously distributed throughout the aerogel framework, e.g., the average pore size can be substantially the same throughout the aerogel framework.

[0124] In other embodiments, the pore size variations within the aerogel skeleton can be heterogeneously distributed throughout the aerogel skeleton. For example, the average pore size can be different in certain regions of the aerogel skeleton. In some exemplary embodiments, the average pore size can be greater at the top surface, the bottom surface, or both the top and bottom regions of the aerogel skeleton. For example, the macropores can be distributed within the composition such that the ratio of macropores to mesopores is greater at the top surface than at the bottom surface, greater at the bottom surface than at the top surface, or greater at both the top and bottom surfaces than at an intermediate region between the top and bottom surfaces. As another example, the macropores can be distributed within the composition such that the ratio of macropores to mesopores is greater near the top surface than at the bottom surface, greater near the bottom surface than at the top surface, or greater near both the top and bottom surfaces than at an intermediate region between the top and bottom surfaces. In other embodiments, the average pore size can be greater in an intermediate region between the top and bottom surfaces of the aerogel skeleton.

[0125] Macropore formation Macropores can be formed during the formation of an aerogel composition. For example, macropore formation can be induced in a gel precursor material during its transition to a gel composition. In some embodiments, macropore formation can be induced, for example, by inducing spinodal decomposition of a gel precursor solution. As another example, macropore formation can be induced by adding one or more foaming agents.

[0126] Macropores present in the resulting aerogel framework can be created by selecting processing conditions that favor the formation of macropores relative to mesopores and / or micropores. The amount of macropores can be adjusted by implementing any one, any combination, or all of the following variables: The variables included: (1) the solvent used for polymerization, (2) the polymerization temperature, (3) the polymer molecular weight, (4) the molecular weight distribution, (5) the copolymer composition, (6) the amount of branching, (7) the amount of cross-linking, (8) the branching method, (9) the cross-linking method, (10) the method used to form the gel, (11) the type of catalyst used to form the gel, (12) the chemical composition of the catalyst used to form the gel, (13) the amount of catalyst used to form the gel, (14) the temperature of gel formation, (15) the type of gas flowing across the material during gel formation, (16) the flow rate of the gas flowing across the material during gel formation, (17) the atmospheric pressure during gel formation, (18) the removal of dissolved gas during gel formation, (19) the presence of solid additives to the resin during gel formation, (20) the time of the gel formation process, (21) the substrate used for gel formation, (22) the type of solvent or solvents used at each step of the solvent exchange process, and (23) the solvent or solvents used at each step of the solvent exchange process. (24) the composition of the solvent used in each step of the solvent exchange process, (25) the residence time of the part in each step of the solvent exchange process, (26) the flow rate of the solvent in the solvent exchange, (27) the type of solvent flow in the solvent exchange, (28) the agitation rate of the solvent in the solvent exchange, (29) the temperature used in each step of the solvent exchange process, (30) the ratio of the volume of the solvent to the volume of the part in the solvent exchange, (31) the drying method, (32) the temperature in each step of the drying process, (33) the pressure in each step of the drying process, (34) the composition of the gas used in each step of the drying process, (35) the rate of gas flow during each step of the drying process, (36) the temperature of the gas during each step of the drying process, (37) the temperature of the part during each step of the drying process, (38) the presence of an enclosure around the part during each step of the drying process, (39) the type of enclosure around the part being dried, and / or (40) the solvent used in each step of the drying process.The polyfunctional amine and diamine compounds may be added separately or together in one or more portions as solids, and may be pure or dissolved in a suitable solvent. In another aspect, a method for making an aerogel may include: (a) providing a polyfunctional amine compound and at least one diamine compound in a solvent to form a solution; (b) providing at least one dianhydride compound to the solution of step (a) under conditions sufficient to form a branched polymer matrix solution, wherein the branched polymer matrix is ​​solubilized in the solution; and (c) exposing the branched polymer matrix solution to conditions sufficient to form an aerogel having an open-cell structure. Macropores present in the resulting aerogel framework can be formed in the manner described above. In a preferred, non-limiting aspect, the formation of macropores, as compared to smaller mesopores and micropores, can be controlled primarily by controlling the polymer / solvent dynamics during gel formation.

[0127] As discussed above, aerogel compositions according to embodiments of the present disclosure can include an aerogel skeleton and a reinforcing material, with at least a portion of the reinforcing material being free of aerogel. For example, the aerogel skeleton can extend partially through the thickness of the reinforcing material. In such embodiments, portions of the reinforcing material, such as OCMF, fibers, or combinations thereof, can include aerogel material, while portions can be free of aerogel. For example, in some embodiments, the aerogel extends through about 90% of the thickness of the reinforcing material, through about 50% to about 90% of the thickness of the reinforcing material, through about 10% to about 50% of the thickness of the reinforcing material, or through about 10% of the thickness of the reinforcing material.

[0128] Without being bound by any particular theory of operation, aerogel compositions in which at least a portion of the reinforcement material is aerogel-free can provide desirable properties of compressibility, resilience, and compliance. For example, the properties of the reinforcement material can be selected to provide sufficient reinforcement and support thermal properties in the aerogel-containing regions, and also to provide sufficient compressibility, resilience, and / or compliance in the aerogel-free regions. The aerogel-containing portion of the reinforced aerogel composition can provide a desired thermal conductivity, e.g., a thermal conductivity of less than about 25 mW / m*K, while the aerogel-free reinforcement portion can provide or improve desired physical properties, e.g., a desired compressibility.

[0129] In some embodiments, reinforced aerogel compositions in which at least a portion of the reinforcing material is free of aerogel can be formed using the methods disclosed herein, where the reinforcing material is combined with a sufficient amount of precursor solution to partially fill the reinforcing material with the precursor solution. For example, the volume of the precursor can be less than the volume of the reinforcing material, so that the precursor extends only partially through the reinforcing portion. As explained above, when dried, the resulting reinforced aerogel composition includes an aerogel skeleton that extends through less than the entire thickness of the reinforcing material. In other embodiments, reinforced aerogel compositions in which at least a portion of the reinforcing material is free of aerogel can be formed by removing a surface aerogel layer from the reinforced aerogel composition.

[0130] In some embodiments, reinforced aerogel compositions, in which at least a portion of the reinforcement material is free of aerogel, can be formed using a reinforcement material that has properties that allow mixing through the thickness of the reinforcement material. For example, the reinforcement material can include multiple layers, each layer having different properties, such as differences in average pore / cell size, material composition, closed cell, open cell, surface treatment, or a combination thereof. The multiple layers can be bonded to each other, for example, using an adhesive, by frame bonding, or by other suitable methods or mechanisms, such as those described herein. The different properties of the reinforcement material can result in varying aerogel distribution through the layers. For example, the open-cell portion of the reinforcement material can contain an aerogel framework, while the closed-cell portion remains substantially free of aerogel. Similarly, other material properties of the reinforcement material or its layers can determine the distribution within the aerogel in the reinforcement material, and thus within the reinforced aerogel composition.

[0131] In some exemplary embodiments, reinforced aerogel compositions can be formed using the methods disclosed herein, in which at least a portion of the reinforcing material does not contain aerogel. The properties of the reinforcing material, or the properties of a layer of the reinforcing material, can control or influence the amount of precursor solution that fills a material or layer, e.g., during a coating process, to provide partial filling of the reinforcing material with precursor solution. For example, one layer of the reinforcing material can have open cells, while another layer of the reinforcing material can have closed cells. When precursor solution is combined with such a reinforcing material, the gel precursor solution can infiltrate the open cells of a layer while not substantially infiltrating the closed cells of the other layer. When such a composition dries, the resulting reinforced aerogel composition can include one portion, e.g., a closed-cell layer, that does not contain aerogel, while another portion, e.g., an open-cell layer, contains aerogel.

[0132] In some embodiments, the additives disclosed herein (e.g., heat-absorbing additives, opacifying additives, fire-rated additives, or other additives) can be non-uniformly dispersed within the reinforced aerogel composition. For example, the additive material can vary through the thickness of the aerogel composition or along the length and / or width of the aerogel composition. For example, the additive can accumulate on one side of the aerogel composition. In some embodiments, the additive material(s) can be collected in one layer of the aerogel composition or can be provided as a separate layer consisting essentially of the additive adjacent to or attached to the composition. For example, a thermal control element can include a layer consisting essentially of a heat-absorbing material such as gypsum, baking soda, magnesia-based cement, etc. In further exemplary embodiments, the aerogel composition can also include at least one layer of an additional material, either within the composition or as a skin layer. For example, the layer can be a layer selected from the group consisting of a polymer sheet, a metal sheet, a fiber sheet, a highly oriented graphite material (e.g., a pyrolytic graphite sheet), and a fabric sheet. In some embodiments, the skin layer can be attached to the composition by an adhesive mechanism selected from the group consisting of aerosol adhesives, urethane adhesives, acrylate adhesives, hot melt adhesives, epoxies, rubber resin adhesives, polyurethane composite adhesives, and combinations thereof. In some embodiments, the skin layer can be attached to the composition by a non-adhesive mechanism, such as by a mechanism selected from the group consisting of frame bonding, needling, stitching, sealing bags, rivets, buttons, clamps, wraps, braces, and combinations thereof. In some embodiments, the skin layer can be attached to the composition using any combination of the aforementioned adhesive and non-adhesive mechanisms.

[0133] Powder aerogel composition As described herein, an aerogel composition or composite can include aerogel particulates, particles, granules, beads, or powders combined with a binder such as an adhesive, resin, cement, foam, polymer, or similar solid or solidifying material to incorporate them into a solid or semi-solid material. For example, an aerogel composition can include a reinforcing material, aerogel particles, and optionally a binder. In an exemplary embodiment, a slurry can be provided that includes aerogel particles and at least one type of wetting agent. For example, the aerogel particles can be coated or wetted with at least one wetting agent, such as a surfactant or dispersant. The aerogel particles can be fully wetted, partially wetted (e.g., surface-wetted), or present in a slurry. Preferred wetting agents are capable of volatilization, allowing for adequate recovery of the hydrophobicity of hydrophobic aerogel particles. If the wetting agent remains on the surface of the aerogel particles, the remaining wetting agent can contribute to the overall thermal conductivity of the composite. Therefore, preferred wetting agents are those that are removable, such as by volatilization, with or without decomposition or other means. Generally, any wetting agent that is compatible with aerogel can be used.

[0134] Wetting agent Wetting agent-coated slurries or aerogels can be useful in methods for easily incorporating hydrophobic aerogels into various materials, such as other aqueous fluids, slurries, adhesives, and binder materials, which can optionally be cured to form solid materials, fibers, metal fibers, discrete fibers, woven materials, nonwoven materials, needle-punched nonwovens, batting, webs, mats, felts, and combinations thereof. Aerogels wetted with at least one wetting agent, or slurries containing aerogels with at least one wetting agent, allow for easy incorporation and uniform distribution of the hydrophobic aerogel. Wet-laid processes, such as those described in U.S. Pat. Nos. 9,399,864, 8,021,583, 7,635,411, and 5,399,422 (each of which is incorporated by reference herein in its entirety), use aqueous slurries to disperse aerogel particles, fibers, and other additives. The slurry can then be dewatered to form layers of aerogel particles, fibers, and additives, which can be dried and optionally calendered to produce an aerogel composite.

[0135] Aerogel particles and additives In other embodiments, the aerogel composition comprises aerogel particles, at least one inorganic matrix material, and optionally, fibers, auxiliary materials, additives, and additional inorganic binders. The inorganic matrix material, in some embodiments, can comprise a phyllosilicate, such as a naturally occurring phyllosilicate such as kaolin, clay, or bentonite, a synthetic phyllosilicate such as magadite or Kenyaite, or a mixture thereof. The phyllosilicate may or may not be burned, for example, by drying the material to remove the water of crystallization. The inorganic matrix material, in some embodiments, can also comprise an inorganic binder, such as cement, lime, gypsum, or a suitable mixture thereof, combined with the phyllosilicate. The inorganic matrix material, in some embodiments, can also comprise other inorganic additives, such as fire-rated additives, opacifiers, or combinations thereof, as disclosed herein. Aerogel compositions comprising inorganic matrix materials and exemplary processes therefor are disclosed in U.S. Patent Nos. 6,143,400 and 6,083,619, each of which is incorporated herein by reference in its entirety. In some embodiments, the aerogel composition may comprise aerogel particles coated on or absorbed within a woven material, a nonwoven material, a needlepunched nonwoven, a batting, a web, a mat, a felt, or combinations thereof. An adhesive binder may be included in the composition. The composition may also include additives such as fire-rated additives, opacifiers, or combinations thereof, as disclosed herein. Aerogel compositions coated on or absorbed into fabric and exemplary processes therefor are disclosed in U.S. Patent Publication No. 2019 / 0264381 A1, which is incorporated herein by reference in its entirety.

[0136] As described herein, the aerogel composition can be laminated to or faced with another material, such as a reinforcing layer of a facing material. In one embodiment, the present disclosure provides a multilayer laminate including at least one base layer comprising a reinforced aerogel composition and at least one skin layer. In one embodiment, the skin layer comprises a reinforcing material. In one embodiment, the reinforced aerogel composition is reinforced with a fiber reinforcement layer or an open-cell foam reinforcement layer. In one embodiment, the present disclosure provides a multilayer laminate including a base layer comprising a reinforced aerogel composition and at least two skin layers comprising a reinforcing material, the two skin layers being on opposite sides of the base layer. For example, multilayer aerogel laminate compositions can be produced according to the methods and materials described in U.S. Patent Application Publication No. 2007 / 0173157.

[0137] The skin layer may include a material that helps provide unique characteristics to the final composite structure, such as improved flexibility or reduced surface dusting. The face material may be rigid or flexible. The face material may include a conductive layer or a reflective foil. For example, the face material may include a metallic or metallized material. The face material may include a nonwoven material. The skin layer may be disposed on the surface of the composite structure or on the surface of the reinforced aerogel composite forming the composite structure, e.g., a thermal control element. The skin layer may form a continuous coating or bag around the composite structure or around the reinforced aerogel composite forming the composite structure, e.g., a thermal control element. In some embodiments, a skin layer or multiple skin layers may encapsulate the composite structure or the reinforced aerogel composite forming the composite structure.

[0138] In one embodiment, the skin layer comprises a polymer sheet around the synthetic structure, more specifically a polymeric material including polyester, polyethylene, polyurethane, polypropylene, polyacrylonitrile, polyamide, aramid, more specifically a polymer such as polyethylene terephthalate, low density polyethylene, ethylene-propylene copolymer, poly(4-methylpentane), polytetrafluoroethylene, poly(1-butene), polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinyl acrylonitrile, polymethyl methacrylate, polyoxymethylene, polyphenylene sulfone, cellulose triacetate, polycarbonate, polyethylene naphthalate, polycaprolactam, polyhexamethylene adipamide, polyundecanoamide, polyimide, or a combination thereof. In one embodiment, the polymer sheet comprises or consists essentially of an expanded polymer material, more specifically, an expanded polymer material including PTFE (ePTFE), expanded polypropylene (ePP), expanded polyethylene (ePE), expanded polystyrene (ePS), or a combination thereof. In one preferred embodiment, the face material consists essentially of an expanded polymer material. In one embodiment, the polymer sheet comprises or consists essentially of a microporous polymer material characterized by pore sizes ranging from 0.1 μm to 210 μm, 0.1 μm to 115 μm, 0.1 μm to 15 μm, or 0.1 μm to 0.6 μm.

[0139] In one embodiment, the skin layer material comprises or consists essentially of a fluoropolymer material. Within the context of this disclosure, the terms "fluoropolymer" or "fluoropolymer material" refer to a material primarily comprising polymeric fluorocarbons. Suitable fluoropolymer skin layer materials include, but are not limited to, polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polychlorotrifluoroethylene (PCTFE), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), ethylene chlorotrifluoroethylene (ECTFE), and combinations thereof, including microporous PTFE as described in U.S. Pat. No. 5,814,405 and expanded PTFE (ePTFE), such as Gore-Tex® (available from WL Gore). In one preferred embodiment, the face material consists essentially of a fluoropolymer material. In one preferred embodiment, the face material consists essentially of an expanded PTFE (ePTFE) material.

[0140] In one embodiment, the skin layer material comprises or consists essentially of a non-fluoropolymer material. Within the context of this disclosure, the terms "non-fluoropolymer" or "non-fluoropolymer material" refer to a material that does not contain a fluoropolymer material. Suitable non-fluoropolymer skin layer materials include, but are not limited to, aluminized Mylar, low-density polyethylene such as Tyvek® (commercially available from DuPont), rubber or rubber composites, nonwoven materials, elastic fibers such as spandex, nylon, Lycra, or elastane, and combinations thereof. In one embodiment, the face material is a flexible face material.

[0141] In some embodiments, the skin layer material can include automotive resins and polymers, such as materials having a maximum use temperature of up to about 100° C., up to about 120° C., or up to about 150° C. For example, the skin layer material can include acrylonitrile butadiene styrene (ABS), polycarbonate ABS, polypropylene, polyurethane, polystyrene, polyethylene, polycarbonate, polyimide, polyamide, PVC, or combinations thereof. For example, aerogel compositions and thermal control members according to embodiments disclosed herein can include a layer of automotive resin or automotive polymer, a metal or metallized layer, and an aerogel layer.

[0142] The skin layer can be attached to the base layer by using an adhesive suitable for securing the inorganic or organic facing material to the reinforcement of the base layer. Examples of adhesives that can be used in the present disclosure include, but are not limited to, cement-based adhesives, sodium silicate, latex, pressure sensitive adhesives, silicone, polystyrene, aerosol-based adhesives, urethane, acrylic adhesives, hot melt bonding systems, bonding systems commercially available from 3M, epoxy resins, rubber resin adhesives, and polyurethane adhesive mixtures such as those described in U.S. Pat. No. 4,532,316.

[0143] The skin layer can also be attached to the substrate by using a suitable non-adhesive or technique to secure the inorganic or organic face material to the support of the substrate. Examples of non-adhesive materials or techniques that can be used in the present disclosure include, but are not limited to, heat sealing, ultrasonic stitching, RF sealing, stitching or threading, needling, sealed bags, rivets or buttons, clamps, wraps, or other non-adhesive lamination materials.

[0144] The skin layer can be attached to the base layer at any stage in the production of the aerogel composite; in one embodiment, the skin layer is attached to the base layer after infusing the sol-gel solution into the base reinforcement but before gelation. In another embodiment, the skin layer is attached to the base layer after infusing the sol-gel solution into the base reinforcement and subsequent gelation but before the gel material ages or dries. In yet another embodiment, the skin layer is attached to the base layer after the gel material ages or dries. In a preferred embodiment, the skin layer is attached to the base layer before infusing the sol-gel solution into the base reinforcement. The skin layer can be solid and impermeable to fluids. The skin layer can be porous and permeable to fluids. In a preferred embodiment, the skin layer is porous and permeable to fluids, including pores or holes with a diameter large enough to allow the fluid to diffuse through the face material. In another preferred embodiment, the skin layer is attached to the base reinforcement prior to injecting the sol-gel solution into the base reinforcement, and the skin layer is porous and includes pores or holes with a diameter large enough to allow fluid to penetrate and diffuse through the face material. In yet another preferred embodiment, the skin layer is attached to the open-cell foam reinforcement prior to injecting the sol-gel solution into the foam reinforcement, and the skin layer is porous and includes pores or holes with a diameter large enough to allow fluid to penetrate and diffuse through the face material.

[0145] opacifier The aerogel composition may include an opacifying agent to reduce the radiative component of heat transfer. At any time prior to gel formation, an opacifying compound or its precursor may be dispersed in the mixture containing the gel precursor. Examples of opacifying compounds include, but are not limited to, boron carbide (B4C), diatomaceous earth, manganese ferrite, MnO, NiO, SnO, Ag2O, Bi2O3, carbon black, graphite, titanium oxide, titanium iron oxide, aluminum oxide, zirconium silicate, zirconium oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, titanium iron oxide (ilmenite), chromium oxide, carbides (such as SiC, TiC, or WC), or mixtures thereof. Examples of precursors to opacifying compounds include, but are not limited to, TiOSC4 or TiOCl2. In some embodiments, silicon carbide whiskers or fibers can be excluded for opacifying compounds used as additives. When an aerogel composition is intended for use in an electrical device, such as in a battery as a barrier layer, or other related application, the composition including the opacifier can desirably possess high dielectric strength with high capacity and high surface resistivity. In such embodiments, the carbon additive used as the opacifier can be non-conductive or modified to reduce electrical conductivity. For example, the opacifier can be surface oxidized to reduce electrical conductivity. In some embodiments, a carbon additive with inherent electrical conductivity can be used as an opacifier in an aerogel composition intended for use in an electrical device. In such embodiments, the conductive carbon additive can be used at a concentration below the percolation threshold to provide the composition with suitable dielectric strength for use in an electrical device.

[0146] Fire Grade Additives The aerogel composition may include one or more fire-rated additives. Within the context of this disclosure, the term "fire-rated additive" refers to a material that provides an endothermic effect in relation to the response to fire and that is miscible with the aerogel composition. Furthermore, in certain embodiments, the fire-rated additive has an endothermic decomposition (ED) onset temperature that is no more than 100° C. above the onset temperature of thermal decomposition (Td) of the aerogel composition in which the fire-rated additive is present, and in certain embodiments, an ED onset temperature that is no more than 50° C. below the Td of the aerogel composition in which the fire-rated additive is present. In other words, the ED of the fire-rated additive is determined by the (T d -50℃)~(T d +100℃).

number

[0147] Prior to, concurrently with, or subsequent to mixing or blending with the sol (e.g., silica sol prepared from alkyl silicates or water glass by various methods as understood in the art), the fire-rated additive can be mixed with or otherwise dispersed in a medium containing ethanol and, optionally, up to 10% water by volume. The mixture can be mixed and / or stirred as needed to achieve a substantially uniform dispersion of the additive in the medium. Without being bound by theory, utilizing the hydrated forms of the aforementioned clays and other fire-rated additives provides an additional endothermic effect. For example, halloysite clay (a product commercially available from Applied Minerals, Inc. under the trade name DRAGONITE or from Imerys simply known as Halloysite) and kaolinite clay are aluminum silicate clays that, in their hydrated form, provide an endothermic effect by releasing water of hydration (gas dilution) at elevated temperatures. As another example, hydrated forms of carbon can release carbon dioxide at elevated temperatures.

[0148] Within the context of this disclosure, the term "heat of dehydration" means the amount of heat required to evaporate water (and dihydroxylate, if applicable) from a material in its hydrated form when not exposed to elevated temperatures. Heat of dehydration is generally expressed on a per unit weight basis.

[0149] In certain embodiments, the fire-rated additives of the present disclosure have an onset temperature of thermal decomposition of about 100° C. or higher, about 130° C. or higher, about 200° C. or higher, about 230° C. or higher, about 240° C. or higher, about 330° C. or higher, 350° C. or higher, about 400° C. or higher, about 415° C. or higher, about 425° C. or higher, about 450° C. or higher, about 500° C. or higher, about 550° C. or higher, about 600° C. or higher, about 650° C. or higher, about 700° C. or higher, about 750° C. or higher, about 800° C. or higher, or a range between any two of these values. In certain embodiments, the fire-rated additives of the present disclosure have an onset temperature of thermal decomposition of about 440° C. or 570° C. In certain embodiments, the fire-rated additives of the present disclosure have an onset temperature of thermal decomposition that is no greater than about 50° C., no greater than about 40° C., no greater than about 30° C., no greater than about 20° C., no greater than about 10° C., no greater than about 5° C., or a range between any two of these values, relative to the Td of the aerogel composition (without the fire-rated additive) into which the fire-rated additive is incorporated.

[0150] Fire-rated additives of the present disclosure include, but are not limited to, the following clay materials: phyllosilicate clays (such as illite), kaolin or kaolinite (aluminum silicate; Al2SiO5(OH)4), metakaolin, halloysite (aluminum silicate; Al2SiO5(OH)4), endellite (aluminum silicate; Al2SiO5(OH)4), mica (silica mineral), diaspore (aluminum oxide hydroxide; α-AlO(OH)), gibbsite (aluminum hydroxide), boehmite (aluminum oxide hydroxide; γ-AlO(OH)), montmorillonite, beidellite, pyrophyllite (aluminum silicate; Al2SiO10(OH)2), nontronite, brabysite, smectite, levalierite, and lectori. Examples of suitable clay materials include gypsum, celadonite, attapulgite, chloropar, volkonscoite, allophane, racewinite, dillnite, sebelite, myrosite, corrilite, simolite, newtonite, sodium bicarbonate (NaHCO), magnesium hydroxide (or magnesium dihydroxide, "MDH"), alumina trihydrate ("ATH"), gypsum (calcium sulfate dihydrate; CaSO 2H O), baringtonite (MgCO 2H O), nesquehonite (MgCO 3H O), lansfordite (MgCO 5H O), hydromagnesium (hydrated magnesium carbonate; Mg(CO)(OH) 4H O), and other carbons, such as, but not limited to, dolomite and lithium carbon. Certain embodiments of the present disclosure utilize clay materials having at least a partial layered structure, among others. In certain embodiments of the present disclosure, the clay material as a fire-rated additive in the aerogel composition has at least some water, such as in a hydrated form. The additive may be in a hydrated crystalline form or may become hydrated during the manufacturing / processing of the disclosed compositions. In certain embodiments, the fire-rated additive also includes a low-melting additive that absorbs heat without changing in chemical composition. Examples of this grade include low-melting glasses, such as inert glass beads. Other additives that may be useful in the disclosed compositions include, but are not limited to, wollastonite (calcium silicate) and titanium dioxide (TiO).In certain embodiments, other additives may include infrared opacifiers such as, but not limited to, titanium dioxide or silicon carbide, low melting point glass frit, ceramifiers such as, but not limited to, calcium silicate, or char formers such as, but not limited to, phosphates and sulfates. In certain embodiments, additives may require special processing considerations, such as techniques to ensure that the additives are uniformly distributed and do not aggregate in large amounts that would cause changes in product performance. Processing techniques may include additional static and dynamic mixers, stabilizers, adjustments to process conditions, and others known in the art.

[0151] Amount of additive The amount of additive in the aerogel compositions disclosed herein can depend on the desired properties of the composition. The amount of additive used during formulation and processing of a sol-gel composition is generally referred to as a weight percent relative to the silica content of the sol. The amount of additive in the sol can vary from about 5 wt% to about 70 wt% by weight relative to the silica content. In certain embodiments, the amount of additive in the sol is 10 wt% to 60 wt% relative to the silica content, and in certain preferred embodiments, the amount is 20 wt% to 40 wt% relative to the silica content. In exemplary embodiments, the amount of additive in the sol relative to the silica content ranges from about 5 wt% to about 20%, from about 10% to about 20%, from about 10% to about 30%, from about 10% to about 20%, from about 30 wt% to about 50 wt%, from about 35 wt% to about 45 wt%, or from about 35 wt% to about 40 wt% relative to the silica content. In some embodiments, the amount of additive in the sol is at least about 10 wt% based on the silica content, or about 10 wt% based on the silica content. In some embodiments, the amount of additive ranges from about 5 wt% to about 15 wt% based on the silica content. In certain embodiments, the additive can be of more than one type. One or more fire-rated additives can also be present in the final aerogel composition. In some preferred embodiments including an aluminum silicate fire-rated additive, the additive is present in the aerogel composition at about 60-70 wt% based on the silica content. For example, in some preferred embodiments including an aluminum silicate fire-rated additive such as kaolin, or a combination of an aluminum silicate fire-rated additive such as kaolin and alumina trihydrate ("ATH"), the total amount of additive present in the aerogel composition is about 30-40 wt% based on the silica content. For example, in some preferred embodiments where the additive comprises silicon carbide, the total amount of additive present in the aerogel composition is about 30-40 wt%, e.g., 35 wt%, based on the silica content. For example, in some preferred embodiments where the additive comprises silicon carbide, the total amount of additive present in the aerogel composition is about 5-15 wt%, e.g., 10 wt%, based on the silica content.

[0152] When referring to the final reinforced aerogel composition, the amount of additive is generally referred to as a weight percent of the final reinforced aerogel composition. The amount of additive in the final reinforced aerogel composition can vary from about 1% to about 50%, from about 1% to about 25%, or from about 10% to about 25% by weight of the reinforced aerogel composition. In exemplary embodiments, the amount of additive in the final reinforced aerogel composition ranges from about 10% to about 20% by weight of the reinforced aerogel composition. In exemplary embodiments, the amount of additive in the final reinforced aerogel composition, as a weight percent of the composition, is about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, or any range between any of the aforementioned percentages. In certain embodiments, the amount of additive in the final reinforced aerogel composition is about 15% by weight of the reinforced aerogel composition. In certain embodiments, the amount of additive in the final reinforced aerogel composition is about 13% by weight of the reinforced aerogel composition. For example, in some preferred embodiments including additives such as silicon carbide, the total amount of additive present in the aerogel composition is about 10-20 wt.%, e.g., about 15 wt.%, by weight of the reinforced aerogel composition. As another example, in some preferred embodiments including additives such as silicon carbide, the total amount of additive present in the aerogel composition is about 3-5 wt.%, e.g., about 4 wt.%, by weight of the reinforced aerogel composition.

[0153] Onset temperature of thermal decomposition of fire-rated additives In certain embodiments, fire-rated additives can be classified or grouped based on their onset temperature of thermal decomposition. For example, fire-rated additives can be classified or grouped as having an onset temperature of thermal decomposition less than about 200°C, less than about 400°C, or greater than about 400°C. For example, additives having an onset temperature of thermal decomposition less than about 200°C include baking soda (NaHCO), nesquehonite (MgCO·3H2O), and gypsum (calcium sulfate dihydrate; CaSO·2H2O). As another example, additives having an onset temperature of thermal decomposition less than about 400°C include alumina trihydrate ("ATH"), hydromagnesium carbonate (hydrated magnesium carbon; Mg5(CO3)4(OH)2·4H2O), and magnesium hydroxide (or magnesium dihydroxide, "MDH"). As another example, additives having an onset temperature of thermal decomposition below about 400° C. include halloysite (aluminum silicate; Al2Si2O5(OH)4), kaolin or kaolinite (aluminum silicate; Al2Si2O5(OH)4), boehmite (aluminum oxide hydroxide; γ-AlO(OH)), or a high temperature phase change material (PCM).

[0154] In certain embodiments of the present disclosure, clay materials, such as aluminosilicate clays such as halloysite or kaolinite, are used as additives in aerogel compositions in dehydrated forms, e.g., metahalloysite or metakaolin. Other additives that may be useful in the compositions of the present disclosure include, but are not limited to, wollastonite (calcium silicate) and titanium dioxide (TiO). In certain embodiments, other additives may include infrared opacifiers, such as, but not limited to, titanium dioxide or silicon carbide, low-melting-point glass frits, ceramifiers, such as calcium silicate, or char-forming agents, such as, but not limited to, phosphates and sulfates. In certain embodiments, additives may require special processing considerations, such as techniques to ensure that the additives are uniformly distributed and do not aggregate excessively, which would cause changes in product performance. Processing techniques may include additional static and dynamic mixers, stabilizers, adjustments to process conditions, and others known in the art. One or more fire-rated additives may also be present in the final aerogel composition.

[0155] In certain embodiments, the inclusion of additives, e.g., aluminosilicate clay-based materials such as halloysite or kaolin, in the disclosed aerogel materials and compositions may result in improved high-temperature shrinkage properties. An exemplary high-temperature shrinkage test method is the "Standard Test Method for Linear Shrinkage of Preformed High-Temperature Thermal Insulation Subject to Soaking Heat" (ASTM C356, ASTM International, West Conshohocken, PA). In such a test, the material, referred to as "heat soak," is exposed to temperatures greater than 1000°C for a period of up to 60 minutes. In certain exemplary embodiments, the disclosed aerogel materials or compositions may have a high-temperature shrinkage, i.e., any combination of linear shrinkage, width shrinkage, thickness shrinkage, or dimensional shrinkage, of about 20% or less, about 15% or less, about 10% or less, about 6% or less, about 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, or a range between any two of these values.

[0156] In some exemplary embodiments, certain basic catalysts used to catalyze precursor reactions may result in trace levels of other alkali metals in the aerogel composition. Trace levels of alkali, e.g., 100-500 ppm, of an aerogel material, such as sodium or potassium, may adversely affect high-temperature shrinkage and thermal durability. However, without being bound by any particular mechanism or theory, aluminosilicate clay-based materials, such as halloysite or kaolin, may sequester released alkali, e.g., sodium or potassium, thereby reducing or eliminating the alkali's effect on shrinkage and thermal durability. In certain embodiments of the present disclosure, the aluminosilicate clay material is dehydrated, e.g., metahalloysite or metakaolin. For example, aerogel materials or compositions containing metakaolin or metahalloysite in amounts greater than about 0.5 wt% relative to the silica content may significantly reduce thermal shrinkage and thermal durability. In an exemplary embodiment, the aerogel material or composition may include an amount of metakaolin or metahalloysite relative to the silica content ranging from about 0.5 wt % to about 3.0 wt %.

[0157] Encapsulation layer or encapsulation material layer In some embodiments, the core of the multilayer material disclosed herein or the multilayer material may be encapsulated by an encapsulating layer. For example, the encapsulating layer may include a layer or layers of material surrounding the multilayer material and / or a coating of material surrounding the multilayer material and / or the core of the multilayer material. For example, the encapsulating layer may include a thin film, layer, envelope, or coating. The encapsulating member may be made of any material suitable for enclosing the composite structure or the reinforced aerogel composite forming the composite structure. For example, the encapsulating member may reduce or eliminate the generation of dust or particulate material shed from the composite structure. The encapsulating material layer may be selected from a polymer, an elastomer, or a combination thereof. Examples of suitable polymers include polyethylene terephthalate (PET), polyethylene (PE), polyimide (PI), and nylon, which have very low thermal conductivities (less than 1 W / m), which have the effect of reducing planar thermal conductivity throughout the system. In one embodiment, the encapsulating layer includes a polyethylene terephthalate layer. In another embodiment, the encapsulating layer includes rubber.

[0158] The encapsulation layer may include at least one vent that allows air to flow in and out of the panel. The encapsulation member may include at least one filter that filters particulate matter. In an exemplary embodiment, the encapsulation layer includes a vent that allows air to flow in and out of the panel and a particulate filter over the vent that keeps particulate matter within the encapsulation member. In another embodiment, the encapsulation layer includes an edge seal that includes at least one vent and at least one particulate filter. In a further embodiment, the encapsulation layer includes an edge seal that includes at least one vent and at least one particulate filter, where the vent in the edge seal allows air to flow in and out of the encapsulation member edge and the filter captures and retains particulate matter in the airflow, preventing particulate matter from contaminating the air outside the encapsulation layer.

[0159] Thermal Capacitance Layer In exemplary embodiments, the multilayer material may include a material or layer of material that provides thermal capacitance (i.e., a heat capacity material), for example, a material having a specific heat capacity of at least about 0.2 J / (g·°C). In some embodiments, the material that provides thermal capacitance has a specific heat capacity of at least about 0.5 J / (g·°C). For example, the material that provides thermal capacitance may include a metal such as aluminum, titanium, nickel, steel, stainless steel, iron, or a combination thereof. In some embodiments, the multilayer material may include a layer or coating of a material that provides thermal capacitance. In some embodiments, the multilayer material may include particles of a material that provides thermal capacitance disposed within a layer of the multilayer material, for example, within a layer of the aerogel composition. In certain embodiments, the multilayer material may include at least one layer of a material that provides thermal capacitance disposed adjacent to the aerogel composition. In certain embodiments, the multilayer material may include at least one layer of a material that provides thermal capacitance disposed between at least two of the multiple layers of the aerogel composition. In exemplary embodiments, the multilayer material may include both thermally conductive and heat capacity materials.

[0160] For example, the multilayer material may include a material that provides both thermal capacitance and thermal conductivity, such as a metal, such as aluminum, titanium, nickel, steel, iron, or a combination thereof. As another example, the multilayer material may include one or more different materials or layers of materials, each of which provides either thermal capacitance, thermal conductivity, or a combination thereof, such as a layer including a metal and a layer including a thermally conductive polymer. Preferably, the thermally conductive layer has a melting temperature of at least 300°C, more preferably at least 600°C, even more preferably at least 1000°C, and even more preferably at least 1500°C.

[0161] In some embodiments, the heat capacity material can be selected from a phase change material. Phase change materials are suitable for a variety of applications in energy storage systems, and it can be appreciated that the material should not only have a relatively high thermal capacitance during a phase change, but also be relatively low cost and self-sustaining, i.e., not require any sealing or special containment over the operating temperature range of the device, e.g., the packaged battery module. Additional desirable properties for energy storage applications include high thermal conductivity to rapidly transport heat away from heat-generating components and the ability to customize the temperature at which the phase change occurs.

[0162] In some embodiments, the heat capacity material has a thermal conductivity along an in-plane dimension of at least about 200 mW / m·K.

[0163] Thermal Conduction Layer The thermally conductive layers disclosed herein have been found to exhibit a significantly increased ability to rapidly dissipate heat throughout the xy plane of the multilayer material, further improving durability under high thermal loads. Examples of high thermal conductivity materials include carbon fiber, graphite, silicon carbide, metals, including but not limited to, copper, steel, stainless steel, aluminum, and the like, as well as combinations thereof.

[0164] In exemplary embodiments, the multilayer material may include a layer of a thermally conductive material, or a material that provides thermal conductivity. The thermally conductive layer of the present disclosure helps dissipate heat away from localized heat loads within a battery module or battery pack. For example, the thermally conductive layer may have a thermal conductivity of at least about 200 mW / m·K along an in-plane dimension. The thermally conductive material may include at least one layer including a metal, carbon, a conductive polymer, or a combination thereof.

[0165] In some embodiments of the above aspects, the multilayer material can include one or more thermally conductive layers, i.e., the multilayer material has a thermal conductivity greater than 50 W / mK, more preferably greater than 100 W / mK, and even more preferably greater than 200 W / mK (all values ​​measured at 25°C). For example, the multilayer material can include at least one layer comprising a thermally conductive material, such as a layer comprising a metal, carbon, a thermally conductive polymer, or a combination thereof. When used in connection with these embodiments, a thermally conductive material refers to an insulating material, e.g., a material having a thermal conductivity greater than that of the aerogel composition. In certain embodiments, the thermally conductive material has a thermal conductivity at least about one order of magnitude greater than that of the aerogel composition. In some embodiments, the multilayer material can include multiple layers of the aerogel composition. In certain embodiments, the multilayer material can include at least one layer of a conductive material disposed adjacent to the aerogel composition. In certain embodiments, the multilayer material can include at least one layer of a conductive material disposed between at least two of the multiple layers of the aerogel composition. In some embodiments, the multi-layer material can include particles of a conductive material disposed within a layer of the multi-layer material, for example, within a layer of an aerogel composition.

[0166] To aid in heat distribution and removal, in at least one embodiment, the thermally conductive layer is coupled to a heat sink. It is recognized that, just as there are various heat sink types and configurations, there are different techniques for coupling a heat sink to a thermally conductive layer, and the present disclosure is not limited to the use of any one type of heat sink / coupling technique. For example, at least one thermally conductive layer of the multilayer material disclosed herein can be in thermal communication with an element of a cooling system of a battery module or battery pack, such as a cooling plate or cooling channel of the cooling system. As another example, at least one thermally conductive layer of the multilayer material disclosed herein can be in thermal communication with other elements of a battery pack, battery module, or battery system that can function as a heat sink, such as a wall of the pack, module, or system, or can be in thermal communication with other elements of the multilayer material disposed between battery cells. As described in more detail herein, thermal communication between the thermally conductive layer of the multilayer material and a heat sink element in a battery system can enable excess heat to be removed from a cell or cells adjacent to the multilayer material to the heat sink, thereby, for example, reducing the impact, severity, or propagation of a thermal event that may generate excess heat.

[0167] Preferably, the thermally conductive layer has a melting temperature of at least 300°C, more preferably at least 600°C, even more preferably at least 1000°C, and even more preferably at least 1500°C.

[0168] The thickness of the thermally conductive layer may depend on various factors, such as the composition, the properties of other elements of the multilayer, such as the compression pad, the number of thermal conductors included in the multilayer material, and the composition. Functionally, the thermally conductive layer should be thick enough to provide the desired in-plane thermal conductivity.

[0169] In some embodiments, the thermally conductive material, e.g., pyrolytic graphite sheet (PGS), can have a thickness of about 0.010 mm, 0.025 mm, 0.05 mm, 0.07 mm, 0.10 mm, or a range between any two of these values, and an in-plane thermal conductivity ranging from about 600 to about 1950 W / mK. In some embodiments, the thermally conductive material, e.g., a metal plate, can have a thickness of about 0.05 mm, about 0.07 mm, about 0.10 mm, about 0.20 mm, about 0.25 mm, about 0.30 mm, about 0.5 mm, about 0.75 mm, about 1 mm, about 1.5 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, or a range between any two of these values.

[0170] In some embodiments, the thermally conductive material can be selected from a phase change material.

[0171] In some embodiments, thermal paste can be used between layers of a multi-layer material to ensure uniform and consistent heat transfer between such layers. As used herein, thermal paste refers to various materials also known as thermal compounds, thermal greases, thermal interface materials (TIMs), thermal gels, thermal pastes, heat sink compounds, and heat sink pastes. For example, a layer of thermal paste can be disposed between the aerogel composition and any other layer, such as a layer or layers containing a thermally conductive or heat-capacitive material, a skin layer or skin layers, or an encapsulation layer.

[0172] Sacrificial material layer In exemplary embodiments, the multilayer material can include a sacrificial material or a layer of sacrificial material. Within the context of the present disclosure, the terms "sacrificial material" or "sacrificial layer" refer to a material or layer that is intended to be sacrificed or at least partially removed in response to mechanical, thermal, chemical, and / or electromagnetic conditions to which the layer is subjected. For example, the sacrificial material or sacrificial layer can decompose when exposed to elevated temperatures, such as those encountered before or during a thermal runaway event in a battery. In some embodiments, the sacrificial material layer can be disposed on an exterior surface. For example, the sacrificial material layer can be disposed on the exterior surface of the core of the multilayer material or on an exterior surface of the multilayer material, e.g., the exterior surface of the multilayer material.

[0173] In exemplary embodiments, the sacrificial material or layer of the present disclosure may include a compressible pad having a compression modulus of about 1 MPa, about 2 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa, about 11 MPa, about 12 MPa, or a range between any two of these values. The sacrificial material layer may be selected from the group consisting of siloxane, polyolefin, polyurethane, phenolic, melamine, cellulose acetate, and polystyrene. In some cases, the material layer is in the form of a foam. In some embodiments, the compressible pad or foam may wear due to exposure to mechanical loads (e.g., cyclic loading). In some embodiments, the compressible pad or foam decomposes after exposure to abnormal mechanical, chemical, and / or thermal events.

[0174] In some embodiments, the onset temperature of chemical decomposition of the sacrificial material layer ranges from about 200°C to about 400°C.

[0175] Suitable foams for use as compressible pads in embodiments disclosed herein have a density of about 1.0 g / cc or less, about 0.90 g / cc or less, about about 0.80 g / cc or less, about 0.70 g / cc or less, about 0.60 g / cc or less, about 0.50 g / cc or less, about 0.40 g / cc or less, about 0.30 g / cc or less, about 0.20 g / cc or less, about 0.16 g / cc, about 0.10 g / cc or less, about 0.08 g / cc or less, or a range between any two of these values; and / or a void volume content of at least about 20 to about 99%, specifically about 30% or greater, based on the total volume of the foam. In an exemplary embodiment, the foam has a density of about 0.08 g / cc to about 0.50 g / cc, a compression force deflection (CFD) of 25% at about 27 kPa to about 55 kPa, and a compression force set at about 70° C. of less than about 10%, specifically less than 5%. CFD is measured according to ASTM D1056 by calculating the force in kPa required to compress the sample to 25% of its original thickness.

[0176] The polymer used in the foam can be selected from various types of thermoplastics, blends of thermoplastics, or thermosets. Examples of thermoplastics that can be used include polyacetal, polyacrylic, styrene-acrylonitrile, polyolefin, acrylonitrile-butadiene-styrene, polycarbonate, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyamide (such as, but not limited to, nylon 6, nylon 6,6, nylon 6,10, nylon 6,12, nylon 11, or nylon 12), polyamideimide, polyarylate, polyurethane, ethylene propylene rubber (EPR), polyarylsulfone, polyethersulfone, polyphenylene sulfide, polyvinyl chloride, polysulfone, polyetherimide, polytetrafluoroethylene, fluorinated ethylene propylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyetherketone, polyetheretherketone, polyetherketoneketones, and the like, or a combination comprising at least one of the foregoing thermoplastics.

[0177] Examples of blends of thermoplastic resins that can be used in the polymer foam include acrylonitrile-butadiene-styrene / nylon, polycarbonate / acrylonitrile-butadiene-styrene, acrylonitrile-butadiene-styrene / polyvinyl chloride, polyphenylene ether / polystyrene, polyphenylene ether / nylon, polysulfone / acrylonitrile-butadiene-styrene, polycarbonate / thermoplastic urethane, polycarbonate / polyethylene terephthalate, polycarbonate / polybutylene terephthalate, thermoplastic elastomer alloys, polyethylene terephthalate / polybutylene terephthalate, styrene-maleic anhydride / acrylonitrile-butadiene-styrene, polyether ether ketone / polyethersulfone, styrene-butadiene rubber, polyethylene / nylon, polyethylene / polyacetal, ethylene propylene rubber (EPR), and the like, or combinations comprising at least one of the foregoing blends.

[0178] Examples of polymeric thermosets that can be used in the polymer foam include polyurethane, epoxy, phenolic, polyester, polyamide, silicone, etc., or combinations comprising at least one of the foregoing thermosets. Blends of thermosets and blends of thermoplastic and thermoset resins can also be used.

[0179] multilayer material As explained above, multilayer materials according to embodiments of the present disclosure offer favorable properties related to compressibility, compressive resilience, and compliance. When used as thermal insulators between cells in a battery module, insulating sheets formed using aerogel compositions can provide resistance to compressive deformation to accommodate cell expansion due to degradation and swelling of the active materials during battery charge / discharge cycles. During initial assembly of a battery module, a relatively low load of 1 MPa or less is typically applied to the thermal insulator, such as the multilayer materials disclosed herein. During use, for example, as cells in a battery module expand or swell during charge / discharge cycles, loads of up to about 5 MPa can be applied to the multilayer materials disclosed herein.

[0180] In exemplary aspects, the present disclosure provides a multilayer material that exhibits a compressibility of less than about 25% at about 25 kPa. Optionally, upon release from compression, the multilayer material may be sufficiently resilient to return to at least about 80%, 75%, 65%, 60%, or 50% of its original thickness. In some embodiments, the multilayer material exhibits a compressibility of less than about 25% in a range of about 25 kPa to about 35 kPa, preferably less than about 50% at about 50 kPa. In some embodiments, the multilayer material exhibits a compressibility in a range of about 25% to about 50% at about 50 kPa. In exemplary embodiments, the multilayer material exhibits a compressibility of less than about 80% at about 245 kPa, e.g., less than about 70% at about 235 kPa. In exemplary embodiments, the multilayer material exhibits a compressibility of less than about 70% at about 345 kPa. The thermal conductivity of the multilayer material including the reinforced aerogel composition is preferably maintained at less than about 25 mW / m*K when the multilayer material is compressed.

[0181] As described herein, a multilayer material can include multiple layers of materials, such as insulating layers, thermally conductive layers, heat capacity layers, encapsulant layers, abrasion-resistant layers, fire / flame-retardant layers, heat-reflective layers, compressible layers, e.g., compressible pads, sacrificial layers, or combinations thereof. The layer combination and configuration of the multilayer material can be selected to obtain a desired combination of properties, such as compressibility, resilience, thermal performance, fire response, and other properties. In some embodiments, the multilayer material includes at least one compressible pad disposed between at least two layers of reinforced aerogel composition. For example, the compressible pad can be a foam or other compressible material, such as polyolefin, polyurethane, phenolic, melamine, cellulose acetate, or polystyrene. In certain embodiments, the multilayer material can also include at least one layer of a thermally conductive or heat capacity layer and at least one of the multiple layers of reinforced aerogel composition. The thermally conductive or heat capacity material can absorb and / or dissipate heat within the multilayer material. In some embodiments, the multilayer material can further include a heat-reflective layer. For example, the heat reflective layer may include a metal foil or sheet.

[0182] In embodiments of multilayer materials including several layers, the layers can be attached to other layers by an adhesive mechanism selected from the group consisting of, for example, aerosol adhesives, urethane adhesives, acrylate adhesives, hot melt adhesives, epoxies, rubber resin adhesives, polyurethane composite adhesives, and combinations thereof. In some embodiments, the layers can be attached by a non-adhesive mechanism, for example, by a mechanism selected from the group consisting of frame bonding, needling, stitching, sealing bags, rivets, buttons, clamps, wraps, braces, and combinations thereof. In some embodiments, multiple layers can be attached together using any combination of the aforementioned adhesive and non-adhesive mechanisms.

[0183] Multilayer material final product Multilayer materials according to embodiments of the present disclosure can be formed into a variety of end products. In the simplest configuration, the multilayer material can be in the form of a sheet. The sheet can be formed continuously or semi-continuously, for example, as a rolled product, or sheets of the desired size and shape can be cut or otherwise formed from a larger sheet. The sheet material can be used to form a thermal barrier between battery cells. In other configurations, the reinforced aerogel composition can be formed into a pouch, for example, to enclose a pouch cell in a battery, or into a cylinder to enclose a cylindrical battery cell.

[0184] The multilayer materials of the present disclosure can be formed into a variety of three-dimensional forms, including paneling, pipe preforms, half-shell preforms, elbows, joints, pouches, cylinders, and other shapes typically required for the application of insulation materials to industrial and commercial applications.

[0185] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0186] As used herein, "about" means "approximately" or "nearly," and in connection with a stated numerical value or range, refers to ±5% of the numerical value. In certain embodiments, the term "about" may include conventional rounding to the nearest significant digit of the numerical value. Additionally, the phrase "about 'x' to 'y'" includes "about 'x' to about 'y'."

[0187] As used herein, the terms "composition" and "composition" are used interchangeably.

[0188] As used herein, the terms "compressible pad" and "compressible layer" are used interchangeably.

[0189] Within the context of this disclosure, the terms "aerogel," "aerogel material," or "aerogel matrix" refer to a gel that includes an interconnected framework with a corresponding network of interconnected pores integrated within the framework, that confines a gas, such as air, as a dispersed interstitial medium, and that is characterized by the following physical and structural properties (as determined by nitrogen porosimetry testing) that are ascribed to aerogels: (a) an average pore size ranging from about 2 nm to about 100 nm; (b) a porosity of at least 80% or greater; and (c) a porosity of at least about 100 nm. 2 / g or more surface area.

[0190] Thus, the aerogel materials of the present disclosure include any aerogel or other open-cell material that meets the defining elements set forth in the preceding paragraph, including materials that can otherwise be classified as xerogels, cryogels, ambigels, microporous materials, etc.

[0191] Additionally, the aerogel material may be further characterized by additional physical properties, including (d) a pore volume of about 2.0 mL / g or greater, particularly about 3.0 mL / g or greater, (e) a density of about 0.50 g / cc or less, particularly about 0.3 g / cc or less, and more particularly about 0.25 g / cc or less, and (f) at least 50% of the total pore volume comprising pores having a pore size between 2 and 50 nm (although, as described in more detail below, embodiments disclosed herein include aerogel scaffolds and compositions containing pores having a pore size greater than 50 nm). However, characterization of a compound as an aerogel material is not required to satisfy these additional properties.

[0192] Within the context of this disclosure, the term "aerogel composition" refers to any composite material that includes an aerogel material as a component of the composition. Examples of aerogel compositions include, but are not limited to, fiber-reinforced aerogel composites, aerogel composites containing additive elements such as opacifiers, aerogel composites reinforced by an open-cell macroporous skeleton, aerogel-polymer composites, and composite materials in which aerogel particulates, particles, granules, beads, or powders are incorporated into a solid or semi-solid material in conjunction with binders, resins, cements, foams, polymers, or similar solid materials. Aerogel compositions are generally obtained from the various gel materials disclosed herein after removal of the solvent. Thus, the aerogel composition may undergo further additional processing or treatment. Additionally, the various gel materials may undergo other additional processing or treatment known or useful in the art before undergoing solvent removal (or liquid extraction or liquid drying).

[0193] The aerogel compositions of the present disclosure can include reinforced aerogel compositions. Within the context of the present disclosure, the term "reinforced aerogel composition" refers to an aerogel composition that includes a reinforcing phase within the aerogel material, where the reinforcing phase is not part of the aerogel framework itself.

[0194] Within the context of this disclosure, the term "fiber-reinforced aerogel composition" refers to a reinforced aerogel composition that includes a fiber reinforcement as the reinforcing phase. Examples of fiber reinforcement include, but are not limited to, discrete fibers, woven materials, dry-laid nonwoven materials, wet-laid nonwoven materials, needle-punched nonwovens, batting, webs, mats, felts, and / or combinations thereof.

[0195] The reinforcing material can be selected from organic polymer-based fibers, inorganic fibers, carbon-based fibers, or combinations thereof. The fiber reinforcing material can comprise a variety of materials, including, but not limited to, polyester; polyolefin terephthalate; poly(ethylene) naphthalate; polycarbonate (e.g., rayon, nylon); cotton (e.g., DuPont Lycra); carbon (e.g., graphite); polyacrylonitrile (PAN); oxidized PAN, uncarbonized heat-treated PAN (such as those manufactured by SGL carbon); glass or glass fiber-based materials (such as S-glass, 901 glass, 902 glass, 475 glass, E-glass); silica-based fibers such as quartz (e.g., Quartz manufactured by Saint-Gobain); Q-felt (Johns Polyaramid fibers such as Manville, Saffil, Durablanket (Unifrax), and other silica fibers, Duraback (Carborundum), Kevlar, Nomex, Sontera (all DuPont), and Conex (Taijin); polyolefins such as Tyvek (DuPont), Dyneema (DSM), and Spectra (Honeywell); other polypropylene fibers such as Typer and Xavan (both DuPont); fluoropolymers such as PTFE, which is sold under the trade names Teflon (DuPont) and Goretex (WLGORE); Nicalon (COI Examples of suitable reinforcement materials include silicon carbide fibers such as silicon carbide fibers (manufactured by Ceramics); ceramic fibers such as Nextel (manufactured by 3M); acrylic polymers; fibers such as wool, silk, linen, leather, and suede; liquid crystal materials such as PBO-Zylon fibers (manufactured by Tyobo), Vectan (manufactured by Hoechst), and Cambrelle fibers (manufactured by DuPont); polyurethane, polyamide, wood fibers, boron, aluminum, iron, and stainless steel fibers, and other thermoplastics such as PEEK, PES, PEI, PEK, and PPS. Glass or fiberglass-based fiber reinforcements can be manufactured using one or more techniques. In certain embodiments, it is desirable to make these materials using carding and cross-lapping or airlaid processes.In exemplary embodiments, carded and cross-wrapped glass or fiberglass-based fiber reinforcement offers certain advantages over airlaid materials. For example, carded and cross-wrapped glass or fiberglass-based fiber reinforcement can provide consistent material thickness for a given basis weight of the reinforcement. In certain additional embodiments, further needling of the fiber reinforcement is desirable, requiring interweaving of the fibers in the z-direction to enhance the mechanical and other properties of the final aerogel composition.

[0196] Within the context of this disclosure, references to "thermal runaway" generally refer to a sudden, rapid increase in cell temperature and pressure due to various operating factors, which may further result in the propagation of excessive temperatures throughout the associated module. Potential causes of thermal runaway in such systems may include, for example, cell defects and / or short circuits (both internal and external), cell breakdown or rupture, such as overcharging or accidental events, and excessive ambient temperatures (e.g., temperatures typically greater than 55°C). Under normal use, cells heat up as a result of their internal resistance. Under normal power / current loads and ambient operating conditions, the temperature within most Li-ion cells can be relatively easily controlled to remain within the 20°C to 55°C range. However, under stressful conditions such as high power draw at high cell / ambient temperatures, as well as individual cell defects, localized heating can suddenly increase. In particular, above a critical temperature, exothermic chemical reactions within the cells become activated. Furthermore, chemical heat generation typically leads to a rapid increase in temperature. As a result, the heat generated far exceeds the available heat dissipation. Thermal runaway can cause temperatures at the cell vent and inside to exceed 200°C.

[0197] Within the context of this disclosure, the term "foam" refers to a material comprising a skeleton of interconnected polymeric structures of substantially uniform composition, with a corresponding network or collection of pores integrated within the skeleton. Foams are formed by dispersing a percentage of gas in the form of bubbles in a liquid or resin foam material, so that the bubbles are retained as pores when the foam material solidifies into a solid structure. Generally, foams can be made using a variety of processes. See, for example, U.S. Patent Nos. 6,147,134, 5,889,071, 6,187,831, and 5,229,429. Accordingly, foam materials of the present disclosure include any material that satisfies the defining elements set forth in this paragraph, including compounds that could otherwise be classified as OCMF materials, macroporous materials, etc. Foams as defined in this disclosure can be of the thermoplastic, elastomeric, and thermosetting (duromeric) types.

[0198] Within the context of the present disclosure, the terms "flexible" and "flexibility" refer to the ability of a material or composition to bend or flex without macrostructural failure. The insulation layers of the present disclosure are capable of bending at least 5°, at least 25°, at least 45°, at least 65°, or at least 85° without macroscopic failure, and / or have a bend radius of less than 4 feet, less than 2 feet, less than 1 foot, less than 6 inches, less than 3 inches, less than 2 inches, less than 1 inch, or less than U inches without macroscopic failure. Similarly, the terms "highly flexible" or "high flexibility" refer to a material that is capable of bending at least 90° without macroscopic failure and / or has a bend radius of less than U inches. Additionally, the terms "classified flexibility" and "classified as flexible" refer to a material or composition that can be classified as flexible according to ASTM C1101 (ASTM International, West Conshohocken, PA).

[0199] The insulating layers of the present disclosure can be flexible, highly flexible, and / or graded flexible. The aerogel compositions of the present disclosure can also be drapeable. Within the context of the present disclosure, the terms "drapeable" and "drape-ability" refer to the ability of a material to bend or flex 90° or more without macroscopic failure and with a radius of curvature of about 4 inches or less. Insulating layers according to certain embodiments of the present disclosure are flexible such that the compositions are non-rigid and can be applied and conformed to three-dimensional surfaces or objects or preformed into various shapes and configurations for ease of installation or application.

[0200] Within the context of this disclosure, the term "additive" or "additive element" refers to a material that can be added to an aerogel composition before, during, or after aerogel formation. Additives can be added to alter or improve desirable properties of the aerogel or to counteract undesirable properties of the aerogel. Generally, additives are added to the aerogel material either before gelation to a precursor liquid, during gelation to a transition state material, or after gelation to a solid or semi-solid material.

[0201] Examples of additives include, but are not limited to, microfibers, fillers, reinforcing agents, stabilizers, thickeners, elastic compounds, opacifiers, coloring or pigment compounds, radiation absorbing compounds, radiation reflecting compounds, fire rating additives, corrosion inhibitors, thermally conductive components, components providing thermal capacitance, phase change materials, pH adjusters, redox modifiers, HCN mitigation agents, off-gassing mitigation agents, conductive compounds, dielectric compounds, magnetic compounds, radar blocking components, hardeners, shrinkage inhibitors, and other aerogel additives known to those skilled in the art. In some embodiments, the component providing thermal capacitance may comprise a material having a specific heat capacity of at least about 0.3 J / (g·°C). In some embodiments, the material providing thermal capacitance has a specific heat capacity of at least about 0.5 J / (g·°C). For example, the material providing thermal capacitance may comprise a metal such as aluminum, titanium, nickel, steel, iron, or a combination thereof. In some embodiments, the multilayer material may include one or more layers or coatings of a material providing thermal capacitance. In some embodiments, the multilayer material can include particles of a material that provides thermal capacitance disposed within one or more insulating layers that include an aerogel composition.

[0202] In certain embodiments, the aerogel compositions, reinforced aerogel compositions, and multilayer materials disclosed herein can perform during a high temperature event, for example, can provide thermal protection during a high temperature event as disclosed herein. A high temperature event can be a temperature drop of at least about 1 cm for at least 2 seconds. 2 at least about 25 kW / m over an area of 2 , at least about 30 kW / m 2 , at least about 35 kW / m 2 , or at least about 40 kW / m 2 It is characterized by a sustained heat flux of approximately 40 kW / m 2The heat flux of 10 cm is related to the heat flux resulting from a typical fire (Behavior of Charring Solids under Fire-Level Heat Fluxes; Milosavljevic, I., Suuberg, EM; NISTIR 5499; September 1994). In special cases, high-temperature events may occur at least approximately 10 cm for a period of at least 1 minute. 2 The heat flux is about 40 kW / m over an area of

[0203] Within the context of this disclosure, the terms "thermal conductivity" and "TC" refer to a measure of the ability of a material or composition to transfer heat between two surfaces on either side of the material or composition where there is a temperature difference between the two surfaces. Thermal conductivity is specifically measured as the heat energy transferred per unit time and per unit surface area divided by the temperature difference. It is usually expressed in SI units as mW / m * K (milliwatts / meter *The thermal conductivity of a material may be determined by the following test methods known in the art. Test methods include, but are not limited to, Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus (ASTM C518, ASTM International, West Conshohocken, PA), Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus (ASTM C177, ASTM International, West Conshohocken,PA), Test Method for Steady-State Heat Transfer Properties of Pipe Insulation(ASTM C335,ASTM International,West Conshohocken,PA), Thin Heater Thermal Conductivity Test(ASTM C1114,ASTM International,West Conshohocken,PA), Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials(ASTM D5470,ASTM International,West Conshohocken,PA), Determination of thermal resistance by means of guarded hot plate and heat flow meter methods(EN 12667,British Standards Institution,United Kingdom), or Determination of steady-state thermal resistance and related properties—Guarded hot plate apparatus (ISO 8203, International Organization for Standardization, Switzerland). It is understood that, although different methods may yield different results, within the context of this disclosure, unless expressly stated otherwise, thermal conductivity measurements are taken in accordance with ASTM C518 standard (Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus) at a temperature of about 37.5°C, ambient atmospheric pressure, and when subjected to a compressive load of about 2 psi. Measurements reported per ASTM C518 generally correlate well with measurements made per EN 12667 with any relevant adjustment for compressive load.

[0204] Additionally, thermal conductivity measurements can be obtained at a temperature of about 10° C. at atmospheric pressure during compression. Thermal conductivity measurements at 10° C. are generally 0.5 to 0.7 mW / mK lower than corresponding thermal conductivity measurements at 37.5° C. In certain embodiments, insulating layers of the present disclosure have a thermal conductivity at 10° C. of about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or a range between any two of these values.

[0205] Within the context of this disclosure, the term "density" refers to a measure of the mass per unit volume of a material or composition. The term "density" generally refers to the apparent density of a material, and similarly to the bulk density of a composition. Density is generally expressed in kg / m 3The density of a material or composition, such as the density of an aerogel, can be determined by methods known in the art, including, but not limited to, Standard Test Method for Dimensions and Density of Preformed Block and Board-Type Thermal Insulation (ASTM C303, ASTM International, West Conshohocken, PA), Standard Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations (ASTM C167, ASTM International, West Conshohocken, PA), Determination of the apparent density of preformed pipe insulation (EN 13470, British Standards Institution, United Kingdom), or Determination of the apparent density of preformed pipe insulation (ISO 18098, International Organization for Standardization, Switzerland). Due to different methods sometimes yielding different results, it is understood that within the context of this disclosure, density measurements are obtained in accordance with ASTM C167 (Standard Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations) for thickness measurements at a compression force of 2 psi unless otherwise specified.In certain embodiments, the aerogel material or composition of the present disclosure has a density of about 1.0 g / cc or less, about 0.90 g / cc or less, about 0.80 g / cc or less, about 0.70 g / cc or less, about 0.60 g / cc or less, about 0.50 g / cc or less, about 0.40 g / cc or less, about 0.30 g / cc or less, about 0.25 g / cc or less, about 0.20 g / cc or less, about 0.18 g / cc or less, about 0.16 g / cc or less, about 0.14 g / cc or less, about 0.12 g / cc or less, about 0.10 g / cc or less, about 0.05 g / cc or less, about 0.01 g / cc or less, or a range between any two of these values.

[0206] The hydrophobicity of an aerogel material or composition can be expressed in terms of water vapor uptake. Within the context of this disclosure, the term "water vapor uptake" refers to a measurement of the potential of an aerogel material or composition to absorb water vapor. Water vapor uptake can be expressed as the percentage (by weight) of water that the aerogel material or composition absorbs or otherwise retains when exposed to water vapor at specific measurement conditions. The water vapor uptake of an aerogel material or composition can be determined by methods known in the art. Known methods include, but are not limited to, the Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation (ASTM C1104, ASTM International, West Conshohocken, PA) and Thermal insulating products for building applications, Determination of long-term water absorption by diffusion (EN 12088, British Standards Institution, United Kingdom). It should be understood that, due to different methods potentially yielding different results, within the context of this disclosure, water vapor uptake measurements are obtained in accordance with ASTM C1104 (Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation) at 49°C and 95% humidity under ambient pressure for 24 hours (modified from 96 hours per ASTM C1104), unless otherwise noted. In certain embodiments, the aerogel materials or compositions of the present disclosure may have a water vapor uptake of about 50 wt% or less, about 40 wt% or less, about 30 wt% or less, about 20 wt% or less, about 15 wt% or less, about 10 wt% or less, about 8 wt% or less, about 3 wt% or less, about 2 wt% or less, about 1 wt% or less, about 0.1 wt% or less, or a range between any two of these values.An aerogel material or composition that has improved water vapor uptake relative to another aerogel material or composition will have a lower water vapor uptake / retention rate relative to the reference aerogel material or composition.

[0207] The hydrophobicity of an aerogel material or composition can be expressed by measuring the equilibrium contact angle of a water droplet at the interface with the surface of the material. The aerogel materials or compositions of the present disclosure can have a water contact angle of about 90° or greater, about 120° or greater, about 130° or greater, about 140° or greater, about 150° or greater, about 160° or greater, about 170° or greater, about 175° or greater, or in a range between any two of these values.

[0208] Within the context of this disclosure, the terms "heat of combustion," "HOC," and "AHC" refer to a measurement of the amount of heat energy released upon combustion or exothermic decomposition of a material or composition. Heat of combustion is typically recorded in units of calories of heat energy released per gram of aerogel material or composition (cal / g) or megajoules of heat energy released per kilogram of material or composition (MJ / kg). The heat of combustion of a material or composition can be determined by methods known in the art, including, but not limited to, Reaction to fire tests for products—Determination of the gross heat of combustion (calorific value) (EN ISO 1716, International Organization for Standardization, Switzerland; EN adopted). Within the context of this disclosure, heat of combustion measurements are obtained in accordance with the EN ISO 1716 standard (Reaction to fire tests for products—Determination of the gross heat of combustion (calorific value)) unless otherwise specified.

[0209] Within the context of this disclosure, all thermal analyses and related definitions refer to measurements made in air at ambient pressure, starting at 25°C and increasing at a rate of 20°C per minute up to 1000°C. Therefore, any changes in any of these parameters must be taken into account (or must be re-done under these conditions) when measuring and calculating the onset temperature of thermal decomposition, peak temperature of heat release, peak temperature of heat absorption, etc.

[0210] Within the context of this disclosure, the terms "onset temperature of thermal decomposition" and "TD" refer to a measurement of the lowest ambient temperature at which a rapid exothermic reaction from the decomposition of an organic material appears within a material or composition. Thermogravimetric analysis (TGA) can be used to measure the onset temperature of thermal decomposition of an organic material within a material or composition. The TGA curve of a material indicates the weight loss (% mass) of the material as it is exposed to an increase in ambient temperature, thus indicating thermal decomposition. The onset temperature of thermal decomposition of a material can be correlated to the intersection of the tangents of the TGA curve: a line tangent to the baseline of the TGA curve, and a line tangent to the TGA curve at the point of maximum slope during the rapid exothermic decomposition event for the decomposition of the organic material. Within the context of this disclosure, measurements of the onset temperature of thermal decomposition of an organic material are obtained using TGA analysis as provided in this paragraph, unless otherwise specified.

[0211] Differential scanning calorimetry (DSC) analysis can also be used to measure the onset temperature of thermal decomposition of a material. The DSC curve of a material indicates the thermal energy (mW / mg) released by the material when it is exposed to a gradual increase in ambient temperature. The onset temperature of thermal decomposition of a material can be correlated to the point on the DSC curve where ΔmW / mg (change in thermal energy output) increases maximally, and thus the DSC curve indicates the amount of heat generated by the aerogel material. Within the context of this disclosure, measurements of the onset temperature of thermal decomposition using DSC, TGA, or both are obtained using a temperature ramp rate of 20°C / min, as further defined in the preceding paragraph, unless otherwise expressly stated. DSC and TGA each provide similar values ​​for this onset temperature of thermal decomposition, and many times, test results are obtained from both DSC and TGA, with tests being run simultaneously.

[0212] Within the context of this disclosure, the terms "endothermic decomposition onset temperature" and "TED" refer to the measured temperature of the lowest ambient temperature at which an endothermic reaction from decomposition or dehydration appears in a material or composition. Thermogravimetric analysis (TGA) can be used to measure the onset temperature of endothermic decomposition in a material or composition. The TGA curve of a material shows the weight loss (% mass) of the material as it is exposed to an increase in ambient temperature. The onset temperature of thermal decomposition of a material can be correlated to the intersection of the tangents of the TGA curve: a line tangent to the baseline of the TGA curve, and a line tangent to the TGA curve at the point of maximum slope during the period of rapid endothermic decomposition or dehydration of the material. Within the context of this disclosure, the measured onset temperature of endothermic decomposition of a material or composition is obtained using TGA analysis as provided in this paragraph, unless otherwise specified.

[0213] Within the context of this disclosure, the terms "furnace temperature rise" and "ΔTR" refer to a measurement of the difference between the maximum temperature (TMAX) of a material or composition under pyrolysis conditions compared to a reference temperature of that material or composition under pyrolysis conditions (usually the final temperature or TFIN). Furnace temperature rise is typically recorded in degrees Celsius or °C. The furnace temperature rise of a material or composition can be determined by methods known in the art, including, but not limited to, Reaction to fire tests for building and transport products: Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland; EN adopted). Within the context of this disclosure, furnace temperature rise measurements are obtained according to conditions equivalent to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test) unless otherwise specified. In certain embodiments, the aerogel compositions of the present disclosure may provide an oven temperature rise of about 100°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, about 50°C or less, about 45°C or less, about 40°C or less, about 38°C or less, about 36°C or less, about 34°C or less, about 32°C or less, about 30°C or less, about 28°C or less, about 26°C or less, about 24°C or less, or a range between any two of these values. Within the context of the stability of the composition at elevated temperatures, an improvement of the first composition over the second composition would be contemplated, for example, for a first composition having a lower oven temperature rise than the oven temperature rise of a second composition. It is contemplated herein that the oven temperature rise of a composition is reduced when one or more fire-rated additives are added relative to the composition.

[0214] Within the context of this disclosure, the terms "flame time" and "TFLAME" refer to a measurement of the flame duration of a material or composition under pyrolysis conditions, where "flame time duration" is the duration of a flame in any part of the visible portion of a test sample that lasts for 5 seconds or more. Flame time is typically recorded in seconds or minutes. The flame time of a material or composition may be determined by methods known in the art, including, but not limited to, Reaction to fire tests for building and transport products: Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland; EN adopted). Within the context of this disclosure, flame time measurements are obtained according to conditions equivalent to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test), unless otherwise specified. In certain embodiments, the aerogel compositions of the present disclosure have a flame time of about 30 seconds or less, about 25 seconds or less, about 20 seconds or less, about 15 seconds or less, about 10 seconds or less, about 5 seconds or less, about 2 seconds or less, or a range between any two of these values. Within the context of this specification, for example, a first composition having a flame time that is shorter than the flame time of a second composition would be considered an improvement of the first composition over the second composition. It is contemplated herein that the flame time of a composition is reduced upon the addition of one or more fire-rated additives compared to a composition that does not contain any fire-rated additives.

[0215] Within the context of this disclosure, the terms "mass loss" and "ΔM" refer to a measurement of the amount of a material, composition, or composite that is lost or incinerated under pyrolytic conditions. Mass loss is typically reported in weight percent or wt%. The mass loss of a material, composition, or composite can be determined by methods known in the art, including, but not limited to, Reaction to fire tests for building and transport products: Noncombustibility test (EN ISO 1182, International Organization for Standardization, Switzerland; EN adopted). Within the context of this disclosure, mass loss measurements are obtained according to conditions equivalent to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test), unless otherwise specified. In certain embodiments, the insulating layer or aerogel composition of the present disclosure can have a mass loss of about 50% or less, about 40% or less, about 30% or less, about 28% or less, about 26% or less, about 24% or less, about 22% or less, about 20% or less, about 18% or less, about 16% or less, or a range between any two of these values. Within the context of this specification, for example, a first composition having a mass loss that is less than the mass loss of a second composition would be considered an improvement of the first composition over the second composition. It is contemplated herein that the mass loss of a composition is reduced when one or more fire-rated additives are added compared to a composition without any fire-rated additives.

[0216] Within the context of this disclosure, the term "peak heat release temperature" refers to a measured temperature of the ambient heat at which the exothermic heat release from decomposition is greatest. TGA analysis, differential scanning calorimetry (DSC), or a combination thereof may be used to measure the peak heat release temperature of a material or composition. DSC and TGA will each provide similar values ​​for peak heat release temperature. Often, tests are run simultaneously, with results obtained from both DSC and TGA. In a typical DSC analysis, heat flow is plotted against temperature rise, and the peak heat release temperature is the temperature at which the highest peak in such a curve occurs. Within the context of this disclosure, measurements of the peak heat release temperature of a material or composition are obtained using TGA analysis as provided in this paragraph, unless otherwise specified.

[0217] In the context of endothermic materials, the term "peak heat absorption temperature" refers to the measured temperature of the ambient heat at which the endothermic heat absorption from decomposition is greatest. TGA analysis, differential scanning calorimetry (DSC), or a combination thereof may be used to measure the peak heat absorption temperature of a material or composition. In a typical DSC analysis, heat flow is plotted versus increasing temperature, and the peak heat absorption temperature is the temperature at which the lowest peak of such a curve occurs. Within the context of the present disclosure, the measured peak heat absorption temperature of a material or composition is obtained using TGA analysis as provided in this paragraph, unless otherwise specified.

[0218] Within the context of this disclosure, the terms "low flammability" and "lowly flammable" hereinafter refer to a material or composition that meets the following combination of properties: i) furnace temperature rise of 50°C or less, ii) flame time of 20 seconds or less, and iii) mass loss of 50 wt% or less. Within the context of this disclosure, the terms "non-flammable" and "non-flammable" hereinafter refer to a material or composition that meets the following combination of properties: i) furnace temperature rise of 40°C or less, ii) flame time of 2 seconds or less, and iii) mass loss of 30 wt% or less. As described herein, it is contemplated that the flammability of a composition (e.g., the combination of furnace temperature rise, flame time, and mass loss) is reduced upon inclusion of one or more fire-rated additives.

[0219] Within the context of this disclosure, the terms "low flammability" and "lowly flammable" refer to a low-flammability material or composition having a total heat of combustion (HOC) of 3 MJ / kg or less. Within the context of this disclosure, the terms "non-flammable" and "non-combustible" refer to a non-flammable material or composition having a heat of combustion (HOC) of 2 MJ / kg or less. As described herein, it is contemplated that the HOC of a composition will be reduced upon inclusion of one or more fire-rated additives.

[0220] Within the context of this disclosure, the term "hydrophobically bonded silicon" refers to silicon atoms within the framework of a gel or aerogel that contain at least one hydrophobic group covalently bonded to the silicon atom. Examples of hydrophobically bonded silicon include, but are not limited to, silicon atoms of silica groups within a gel framework formed from a gel precursor containing at least one hydrophobic group (such as MTES or DMDS). Hydrophobically bonded silicon may also include, but is not limited to, silicon atoms on the gel framework or gel surface that have been treated with a hydrophobizing agent (such as HMDZ) to impart or improve hydrophobicity by incorporating additional hydrophobic groups into the composition. Hydrophobic groups of the present disclosure include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isopropyl, tert-butyl, octyl, phenyl, or other substituted or unsubstituted hydrophobic organic groups known to those skilled in the art. Within the context of this disclosure, the terms "hydrophobic group," "hydrophobic organic material," and "hydrophobic organic content" specifically exclude easily hydrolyzable organosilicon-bonded alkoxy groups on the backbone of the gel material, which are the reaction product of organic solvents and silanol groups. Such excluded groups are distinguishable from this hydrophobic organic content by NMR analysis. NMR spectroscopy, such as CP / MAS29Si Solid State NMR, can be used to analyze the amount of hydrophobically bonded silicon encapsulated in the aerogel. NMR analysis of aerogels allows for the characterization and associated quantification of M-type hydrophobic bonded silicon (monofunctional silica, such as TMS derivatives), D-type hydrophobic bonded silicon (bifunctional silica, such as DMDS derivatives), T-type hydrophobic bonded silicon (trifunctional silica, such as MTES derivatives), and Q-type silicon (tetrafunctional silica, such as TEOS derivatives). NMR analysis can also be used to analyze the bonding chemistry of the hydrophobic silicon contained in the aerogel by allowing for categorization of specific types of hydrophobically bonded silicon into subtypes (such as categorizing T-type hydrophobic silicon into T1, T2, and T3 species).Specific details regarding NMR analysis of silica materials can be found in the article by Geppi et al., "Applications of Solid-State NMR to the Study of Organic / Inorganic Multicomponent Materials," Appl. Spec. Rev. (2008), 44-1:1-89, specifically pages 7-9, which is hereby incorporated by reference according to the specifically cited pages.

[0221] Characterization of hydrophobically bonded silicon by CP / MAS 29Si NMR can be analyzed based on the following chemical shift peaks: Ml (30 to 10 ppm); DI (10 to -10 ppm), D2 (-10 to -20 ppm); T1 (-30 to -40 ppm), T2 (-40 to -50 ppm), T3 (-50 to -70 ppm); Q2 (-70 to -85 ppm), Q3 (-85 to -95 ppm), and Q4 (-95 to -110 ppm). These chemical shift peaks are approximate and illustrative and are not intended to be limiting or restrictive. The exact chemical shift peaks attributed to various silicon species within a material may depend on the specific chemical composition of the material and can generally be determined by one of ordinary skill in the art through routine experimentation and analysis.

[0222] Within the context of this disclosure, the terms "hydrophobic organic content" or "hydrophobe content" or "hydrophobic content" refer to the amount of hydrophobic organic material attached to the framework of an aerogel material or composition. The hydrophobic organic content of an aerogel material or composition can be expressed as a weight percent of the amount of hydrophobic organic material on the aerogel framework compared to the total amount of material in the aerogel material or composition. The hydrophobic organic content can be calculated by one skilled in the art based on the nature and relative concentrations of the materials used in forming the aerogel material or composition. Alternatively, thermogravimetric analysis (TGA) of the material can be used to measure the hydrophobic organic content, preferably in an oxygen atmosphere (although TGA in alternative gas environments is also useful). Specifically, the percentage of hydrophobic organic material in an aerogel can be correlated to the rate of weight loss of the hydrophobic aerogel material or composition when exposed to combustion heat temperatures during TGA analysis, with adjustments made for water loss, residual solvent loss, and easily hydrolyzable alkoxy groups during TGA analysis. Other alternative techniques, such as differential scanning calorimetry, elemental analysis (especially carbon), chromatographic techniques, nuclear magnetic resonance spectroscopy, and other analytical techniques known to those skilled in the art, can be used to measure and determine the hydrophobic content of the aerogel compositions of the present disclosure. In some cases, a combination of known techniques may be useful or necessary in determining the hydrophobic content of the aerogel compositions of the present disclosure.

[0223] The aerogel materials or compositions of the present disclosure can have a hydrophobic organic content of 50 wt% or less, 40 wt% or less, 30 wt% or less, 25 wt% or less, 20 wt% or less, 15 wt% or less, 10 wt% or less, 8 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, 2 wt% or less, 1 wt% or less, or a range between any two of these values.

[0224] The term "fuel content" refers to the total amount of combustible material in an aerogel material or composition, which can be correlated to the total percentage weight loss of the aerogel material or composition when exposed to heat of combustion temperatures during TGA or TG-DSC analysis, with an adjustment made for water loss. The fuel content of an aerogel material or composition can include hydrophobic organic content, as well as other flammable residual alcohol solvents, fillers, reinforcing materials, and easily hydrolyzable alkoxy groups.

[0225] Within the context of this disclosure, the term "ormosil" includes the aforementioned materials, as well as other organically modified materials, sometimes also referred to as "ormocera." Ormosils are often used as coatings, where an ormosil film is deposited on a substrate, for example, through a sol-gel process. Examples of other organic-inorganic hybrid aerogels of the present disclosure include, but are not limited to, silica-polyether, silica-PMMA, silica-chitosan, carbides, nitrides, and other combinations of the aforementioned organic-inorganic aerogels to form compounds. Published U.S. Patent Application No. 20050192367 (paragraphs

[0022] -

[0038] and

[0044] -

[0058] ) contains teachings of such hybrid organic-inorganic materials and is hereby incorporated by reference according to the individually cited sections and paragraphs.

[0226] Use of multi-layer materials within a battery module or battery pack Lithium-ion batteries (LIBs) are considered one of the most important energy storage technologies due to their high operating voltage, low memory effect, and high energy density compared to conventional batteries. However, safety concerns pose significant barriers to the large-scale use of LIBs. Under extreme conditions, exothermic reactions can result in heat release that can trigger subsequent dangerous reactions. The situation worsens when heat release from the cell under extreme conditions can activate chain reactions, resulting in sudden thermal runaway.

[0227] With the continuous improvement of the energy density of LIBs, enhancing their safety is becoming increasingly urgent with regard to the development of electric devices, such as electric vehicles. The mechanisms behind safety issues vary for different battery chemistries. This technology focuses on the preparation of multilayer materials and their corresponding configurations to obtain favorable thermal and mechanical properties. The multilayer materials of this technology provide effective heat dissipation measures under normal conditions as well as under thermal runaway conditions, while ensuring the stability of LIBs under normal operating modes (e.g., withstanding applied compressive stress).

[0228] The multilayer materials disclosed herein are useful for separating, insulating, and protecting battery cells or battery components of any configuration of battery, such as pouch cells, cylindrical cells, prismatic cells, as well as packs and modules incorporating or including any such cells. The multilayer materials disclosed herein are useful in rechargeable batteries, such as lithium ion batteries, solid-state batteries, and any other energy storage device or technology requiring separation, insulation, and protection.

[0229] Passive devices such as cooling systems may be used in conjunction with the multilayer materials of the present disclosure within a battery module or battery pack.

[0230] The multilayer material according to various embodiments of the present disclosure of a battery pack includes a plurality of single battery cells or modules of battery cells to thermally isolate the single battery cells or modules of battery cells from one another.

[0231] In an exemplary embodiment, a battery module includes two or more battery cells arranged in a housing. FIG. 10 is a schematic diagram of a prior art battery module. The battery module 1000 includes one or more battery cells 1010 with spacers 1020 positioned between the battery cells. The battery cells 1010 and spacer elements 1020 are positioned within a housing 1030. The housing 1030 has an inner surface defined by a first end plate 1030a, a second end plate 1030b, a first side wall 1030c, and a second side wall 1030d. The battery module also has top and bottom plates (not shown in FIG. 10) that seal the housing. The spacer elements 1020 are typically formed from a non-conductive, thermally insulating material. As shown in FIG. 10, the spacer elements of conventional battery modules typically do not extend beyond the edges of the cells and / or the walls of the housing. Such a device can be useful for preventing direct heat conduction between the battery cells. However, this arrangement may not address the containment or direction of hot gases and particulate matter that can be expelled from the battery cells when they fail. As can be seen in Figure 10, hot gases and other materials emitted from the battery cells can pass around the edges of the spacer elements and transfer heat to other cells in the module. This can predispose other battery cells in the module to failure due to overheating.

[0232] In embodiments disclosed herein, spacer elements can be positioned between each battery cell or between groups of battery cells. For example, a battery module can include groups of battery cells with spacer elements between each group of cells. The groups of cells can have any number of cells, such as two, three, four, five, six, seven, or more. Each group of cells between spacer elements within a battery module can have the same number of cells, or the groups can have different numbers of cells. The number of cells in a group of cells between spacer elements can be selected based on factors including the total amount of thermal potential energy released in thermal runaway of one or more cells in the group and the amount of thermal energy that can be blocked or absorbed by the spacer elements.

[0233] 11A-11B illustrate an exemplary embodiment that addresses the shortcomings of the prior art. FIG. 11A illustrates a top view of a battery module 1100. FIG. 11B illustrates a cutaway view of the battery module 1100. Similar to conventional battery modules, the battery module 1100 includes one or more battery cells 1110 with spacer elements 1120 positioned between the battery cells. The battery cells 1110 and spacer elements 1120 are positioned within a housing 1130. The housing 1130 has an inner surface defined by a first end plate 1130a, a second end plate 1130b, a first side wall 1130c, and a second side wall 1130d. The battery module 1100 also includes a top plate 1140 and a bottom plate 1150 (shown in FIG. 11B) that seal the housing. The spacer elements 1120 are formed from a non-conductive, thermally insulating material.

[0234] In the battery module 1100, the spacer elements 1120 extend so that they contact the inner surface of the housing. The extension of the spacer elements in this configuration creates a thermal barrier between adjacent battery cells. In a specific embodiment, two or more battery cells 1110 are oriented longitudinally between a first sidewall 1130c and a second sidewall 1130d, parallel to a first end plate 1130a and a second end plate 1130b. The spacer elements 1120 contact the bottom plate 1150, the top plate 1140, the first sidewall 1130c, and the second sidewall 1130d, creating a thermal barrier between adjacent battery cells.

[0235] In some embodiments, each of the spacer elements contacts one or more channels formed in the interior surface of the housing. Figures 12A and 12B illustrate an embodiment of a battery module that uses channel spacer elements to form a thermal barrier between battery cells or groups of battery cells. The battery module 1200 shown in Figure 12A includes one or more battery cells 1210 with spacer elements 1220 positioned between them. The spacer elements 1220 are formed from a non-conductive, thermally insulating material. The battery cells 1210 and spacer elements 1220 are positioned within a housing 1230. The housing 1230 has an interior surface defined by a first end plate 1230a, a second end plate 1230b, a first side wall 1230c, and a second side wall 1230d. The battery module 1200 also has top and bottom plates (not shown) that seal the housing.

[0236] To create a good seal at the interface between the spacer elements and the inner surface of the housing, one or more channels can be formed in and / or on the inner surface of the housing. In FIG. 12A , the battery module 1200 includes channels 1260 formed in at least the first sidewall 1230a and the second sidewall 1230b. While only the sidewalls are shown, it should be understood that multiple channels can protrude from one or more of the first end plate, the second end plate, the first sidewall, the second sidewall, the top plate, and the bottom plate. Each of the spacer elements 1220 extends into a pair of opposing channels 1260. The spacer elements contact a portion of the channels, forming a seal between the spacer elements and the inner surface. As used herein, the term “seal” refers to contact between two elements (e.g., a spacer element and a channel) that prevents hot gases and particulate matter from transmitting from a failed battery cell to an adjacent battery cell. In some embodiments, the spacer elements contact at least the sidewalls of the protruding channels. The spacer element may contact the channel by a press fit, in which the spacer element is slightly compressed when placed in the channel, so that a seal is formed between the spacer element and the channel.

[0237] The channel can be U-shaped (as shown in FIG. 12A ) or any other shape that complements the spacer element. The U-shaped channel has opposing sidewalls and a bottom. In some embodiments, the spacer element contacts opposing sidewalls of the U-shaped channel, forming a seal between the spacer element and the U-shaped channel. In some embodiments, the spacer element extends into the channel but does not extend to the bottom of the channel. As shown in FIG. 12A , a gap 1262 exists between the spacer element and the bottom of the U-shaped channel. The gap can allow for manufacturing variations in the spacer element and the housing. Leaving a gap helps ensure that the spacer element fits properly into the channel during assembly of the battery module.

[0238] 12B, the battery module 1200 includes channels 1260 formed in at least a first sidewall 1230c and a second sidewall 1230d. Each of the spacer elements 1220 extends into a pair of opposing channels 1260. The spacer elements contact a portion of the channels forming a seal between the spacer elements and the interior surface. In some embodiments, the spacer elements contact at least the sidewalls of the recessed channels. As explained above, the spacer elements may contact the channels by a press fit.

[0239] Channel 1260 can be U-shaped (as shown in FIG. 12B) or any other shape that complements the spacer element. The U-shaped channel has opposing sidewalls and a bottom. In some embodiments, the spacer element contacts opposing sidewalls of the U-shaped channel, forming a seal between the spacer element and the U-shaped channel. The spacer element extends into channel 1260 but does not extend to the bottom of the channel. As shown in FIG. 12B, a gap 1262 exists between the spacer element and the bottom of the U-shaped channel to accommodate manufacturing variations.

[0240] Spacer elements are used to create a thermal barrier between battery cells, preventing heat transfer from one battery cell to another during normal use and during battery cell failure. The spacer elements can form a physical barrier between battery cells or groups of battery cells by contacting the inner surface of the housing. In this way, separate compartments are created, each holding a single battery cell or multiple battery cells. A compartment is defined by two spacer elements, with the battery cell or cells positioned between the spacer elements. In FIG. 11A, the compartments are indicated by dashed boxes 1180.

[0241] When a battery cell fails, it can experience thermal runaway. During thermal runaway, the battery cell can reach temperatures exceeding 90°C. At temperatures above 90°C, the battery cell's components begin to degrade, eventually causing the battery cell to burst open, releasing heated gases and particles into the battery module. Creating a compartment that thermally isolates the battery cell reduces heat transfer from the failed battery cell to the operating battery cells. Rapid release of gas from the failed battery cell at high temperatures can lead to an increase in pressure within the compartment. In some cases, this increase in pressure can result in failure of the spacer element or the housing itself. In some embodiments, the housing includes one or more vent ports. The one or more vent ports are fluidly coupled to one or more of the compartments defined by the spacer element. The vent port can be an opening formed in a portion of the housing. Alternatively, a pressure relief valve can be used as the vent port.

[0242] The vent ports can be in the sidewalls or top plate of the housing that communicate with one or more of the compartments. Figure 13 shows an embodiment of a top plate 1300 of the housing. Multiple vent ports 1350 are formed in the top plate, each vent port aligned with a compartment. While Figure 13 shows the vent ports on the top plate of the battery module, it should be understood that the vent ports can be located in the sidewall edges, end plates, or bottom plate of the housing, in any combination.

[0243] An alternative embodiment of a battery module is shown in FIG. 14. The battery module 1400 includes one or more battery cells 1410 with spacer elements 1420 positioned between the battery cells. The battery cells 1410 and spacer elements 1420 are positioned within a housing 1430. The housing 1430 has an inner surface defined by a first end plate 1430a, a second end plate 1430b, a first side wall 1430c, and a second side wall 1430d. The battery module 1400 also has top and bottom plates (not shown) that seal the housing. Edge elements 1450 are disposed along the inner surface of the housing.

[0244] 15 shows a close-up view of the edge element 1450 contacting the top plate 1440 of the housing and spacer element 1420. An adhesive material may secure the edge element to the interior surface. The edge element 1450 is compressible and comprises a material having an onset temperature of chemical decomposition, including temperatures of about 100°C or higher, about 130°C or higher, about 200°C or higher, about 230°C or higher, about 240°C or higher, about 330°C or higher, 350°C or higher, about 400°C or higher, about 415°C or higher, about 425°C or higher, about 450°C or higher, about 500°C or higher, about 550°C or higher, about 600°C or higher, about 650°C or higher, about 700°C or higher, about 750°C or higher, about 800°C or higher, or a range between any two of these values. The edge elements are preferably positioned along the sidewalls of the housing (1430c and 1430d) between the ends of the spacer elements 1420 and the interior surface of the housing. The edge elements 1450 contact the spacer elements 1450, forming a seal between the spacer elements and the housing. In this manner, a thermal barrier is created between adjacent battery cells. The use of appropriate edge elements also helps limit the diffusion of particulate matter from battery cells experiencing thermal runaway.

[0245] Several materials can be used for the edge elements. As noted above, these materials should be compressible and have the following onset temperatures for chemical decomposition: about 100°C or higher, about 130°C or higher, about 200°C or higher, about 230°C or higher, about 240°C or higher, about 330°C or higher, 350°C or higher, about 400°C or higher, about 415°C or higher, about 425°C or higher, about 450°C or higher, about 500°C or higher, about 550°C or higher, about 600°C or higher, about 650°C or higher, about 700°C or higher, about 750°C or higher, about 800°C or higher, or a range between any two of these values. In one embodiment, the edge elements are formed from an expansion material. An expansion material is a material that expands when exposed to heat. In the context of a battery module, when a battery cell begins to fail, the temperature of the battery cell increases rapidly, which can increase the temperature inside the module. This temperature increase can cause thermally induced expansion of the expansion material used to form the edge elements, increasing the seal between the spacer elements and the interior surface of the housing. This pressure increase can provide improved resistance to high-pressure gases and particulate matter released if the battery cell is forced open. Exemplary expansion materials are disclosed in U.S. Pat. No. 3,513,114 to Hahn et al., U.S. Pat. No. 5,487,946 to McGinniss et al., U.S. Pat. No. 5,591,791 to Deogon, U.S. Pat. No. 5,723,515 to Gottfried, U.S. Pat. No. 6,790,893 to Nguyen et al., PCT Patent Application Publication No. WO 94 / 17142 to Buckingham et al., PCT Patent Application Publication No. WO 98 / 04639 to Janci, and PCT Patent Application Publication No. WO 2020 / 077334 to Fleetwood et al., all of which are incorporated by reference in their entireties.

[0246] Other polymeric materials can also be used as edge element materials. Generally, polymeric materials that are stable at high temperatures and have significant compressibility are ideal for use as edge element materials. Exemplary polymeric materials that can be used include silicone polymers (polysiloxanes, fluorosilicones), FKM polymers (fluoroelastomers such as VITON), chlorosulfonated polyethylene rubber (HYPALON), hydrogenated acrylonitrile butadiene rubber, and ethylene-propylene-diene monomer. These and other polymers can be in the form of foams or elastic materials. The elastic materials can be formed into the shape of a thin film or gasket.

[0247] In another embodiment, the edge material may be a composite material made up of different layers. For example, the edge material may be made up of a capacitive layer and one or more insulating layers, with a compressive layer formed on the insulating layer. In some embodiments, the edge element is formed from a multi-layer material, as described previously herein.

[0248] As described above, spacer elements are used to create a thermal barrier between battery cells, preventing heat transfer from one battery cell to another during normal use and during battery cell failure. The spacer elements can contact the edge elements to form a physical barrier between the battery cells or groups of battery cells, forming a seal between the inner surface of the housing and the spacer elements. In this manner, separate compartments are created, each holding a single battery cell or multiple battery cells. The compartments are defined by two spacer elements and an edge element, and the battery cell or cells are positioned between the spacer elements.

[0249] As previously described, the housing may include one or more vent ports. The one or more vent ports are fluidly coupled to one or more of the compartments defined by the spacer element and the edge element. The vent port may be an opening formed in a portion of the housing. Alternatively, the vent port may comprise a pressure relief valve that opens at a predetermined internal pressure. In some embodiments, multiple vent ports are formed in the top plate, each vent port aligned with a compartment. The vent ports may also be located in the sidewall edges, end plate, or bottom plate of the housing, in any combination.

[0250] An alternative embodiment of a battery module is shown in FIG. 16. As previously described, the battery module includes a housing having an inner surface. The inner surface is defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate. The battery module includes two or more battery cells and spacer elements between adjacent battery cells. In this embodiment, one or more caps are used to form a seal between the spacer elements and the inner surface of the housing. The caps contact a portion of the inner surface of the housing and surround at least a portion of the spacer elements.

[0251] An embodiment of the cap is shown in FIG. 16. In FIG. 16, a cap 1615 is coupled to an inner surface 1630 of a battery module housing. In this embodiment, the cap 1615 is attached to the inner surface 1630 of the battery module housing. A space can be defined inside the cap 1615 that can receive a spacer element 1620. Preferably, the space has a width substantially equal to the width of the spacer element. During manufacture of the battery module, the spacer element is positioned inside the space defined by the cap 1615 as shown in FIG. 16.

[0252] In a preferred embodiment of the cap 1615, the cap has a substantially U-shaped opening extending along a first longitudinal side of the cap. As shown in FIG. 16, a spacer element 1620 fits within the U-shaped opening formed in the cap. The cap 1615 may also have one or more recesses 1625 or other shapes so that the outer surface of the cap has a shape that complements the shape of a portion of the inner surface of the housing. In some embodiments, the cap 1615 may have an opening at the bottom of the cap. Having an opening at the bottom of the cap allows the cap to slide over the spacer element. This is a convenient feature for manufacturing purposes, as the battery cells, or spacer elements, can be assembled inside the housing before the cap is installed in place.

[0253] To create a thermal and particulate barrier between the battery cells, the cap 1615 may completely cover the edges of one or more spacer elements. When the spacer elements are coupled to the cap, the cap exerts slight pressure on the spacer elements, forming a seal between the cap and the spacer elements at the points of contact. To seal adjacent battery cells from one another, the cap may contact the bottom and top plates of the housing. Specifically, the cap may have a top surface that forms a seal with the top plate of the housing and a bottom surface that forms a seal with the bottom of the housing. In this configuration, the cap forms a sufficient barrier between adjacent battery cells.

[0254] To create a good seal at the interface between the spacer element and the inner surface of the housing, one or more channels 1660 can be formed in and / or on the inner surface of the housing. In FIG. 16 , the channels 1660 are formed in at least the first and second side walls. The channels can protrude from one or more of the first end plate, the second end plate, the first side wall, the second side wall, the top plate, and the bottom plate. The cap 1615 extends into and contacts a portion of the channel, forming a seal between the cap and the inner surface. The cap can contact the channel by a press fit, in which the cap is slightly compressed when placed in the channel, forming a seal between the cap and the channel. Alternatively, an adhesive can be used to attach the channel to the housing. The channel can be U-shaped (as shown in FIG. 16 ) or any other shape that complements the cap.

[0255] In some embodiments, the cap 1615 extends completely into the channel 1660, so that the cap contacts the sidewalls and bottom of the channel. In such embodiments, a gap 1665 is intentionally left between the spacer element and the inner surface of the cap. The gap can allow for manufacturing variations in the spacer element and the housing. Leaving the gap helps ensure that the spacer element fits properly into the cap during assembly of the battery module. By designing the module so that a gap exists between the spacer element and the inner surface of the cap, the gap, necessary for manufacturing purposes, helps ensure that the gap does not unintentionally create a path for hot air and particulate matter to travel from one battery cell to another.

[0256] FIG. 17 shows an alternative embodiment of the cap and spacer element configuration. In this embodiment, the spacer element 1720 extends completely into the cap 1715. In some embodiments, the spacer element may contact opposing sidewalls and the bottom surface of the cap, as shown in FIG. 17. As in the previous embodiment, the use of a gap can allow for manufacturing variations in the spacer element and the housing. In this particular embodiment, a gap 1765 exists between the cap 1715 and the sidewall of the housing. The cap 1715 is coupled to the sidewall by contact with the channel 1760. Preferably, friction and / or a press fit is used to couple the cap 1715 to the channel 1760. The use of a non-adhesive bond of the cap to the housing allows the cap to move to accommodate changes in the length of the spacer element.

[0257] The tube 1715 can be made of any suitable material. Suitable materials include injection molded polymers. Exemplary injection molded polymers include, but are not limited to, polypropylene, acrylonitrile butadiene styrene, polyethylene, polyamide, polycarbonate, and polystyrene. Preferably, a polymer is used that has an onset temperature of chemical decomposition greater than 150°C. Using a high temperature material to form the cap provides additional protection to the battery cell during a thermal runaway incident.

[0258] As described above, spacer elements are used to create a thermal barrier between battery cells, preventing heat transfer from one battery cell to another during normal use and during battery cell failure. The spacer elements can contact the cap to form a physical barrier between the battery cells or groups of battery cells, forming a seal between the inner surface of the housing and the spacer elements. In this way, separate compartments are created, each holding a single battery cell or multiple battery cells. The compartments are defined by two spacer elements coupled to the cap, with the battery cell or multiple battery cells positioned between the spacer elements.

[0259] As previously described, the housing may include one or more vent ports. The one or more vent ports are fluidly coupled to one or more of the compartments defined by the spacer element and the cap. The vent port may be an opening formed in a portion of the housing. Alternatively, the vent port may comprise a pressure relief valve that opens at a predetermined internal pressure. In some embodiments, multiple vent ports are formed in the top plate, each vent port aligned with a compartment. The vent ports may be located in any combination on the sidewall edges, end plate, or bottom plate of the housing.

[0260] In some embodiments, the battery module includes two or more battery cells and one or more spacer elements disposed between adjacent battery cells, each of the spacer elements including at least one heat capacity layer and at least one insulating layer. In some embodiments, the spacer elements have a surface area greater than the surface area of ​​the two or more battery cells, and each of the spacer elements extends beyond an outer surface of the battery cells.

[0261] In specific embodiments, the spacer elements extend above the top surfaces of the battery cells. The spacer elements may extend past the edges of the battery cells and contact the casing of the module. Alternatively, the spacer elements may be curved such that a portion of the spacer elements extends above the top surfaces of the battery cells.

[0262] In some embodiments, a heat capacity layer, a heat conduction layer, some other layer of the spacer element, or a combination of these layers extends from the insulating layer and contacts the casing of the module. In an exemplary embodiment, the insulating layer has a surface area substantially equal to the surface area of ​​the battery cell, and the heat capacity layer, the heat conduction layer, another layer, or a combination of these layers of the spacer element extends beyond the outer surface of the battery cell. The heat capacity layer, the heat conduction layer, another layer, or a combination of these layers of the spacing element can be disposed on the outer surface of the insulating layer or between two or more layers of insulating material. In some embodiments, the insulating layer or layers can be encapsulated, for example, by a polymer layer or wrap, separate from the heat capacity layer or layers. The heat capacity layer, the heat conduction layer, another layer, or a combination of these layers of the spacer extends beyond the insulating layer and contacts the inner surface of the housing. During a thermal runaway event, the casing of the battery cell can fail, allowing the release of hot gases and hot and / or burning particulate matter (ejecta). These materials are released from the cells into the region of the insulating layer. Because the released materials are hot, the insulating layer may be at least partially damaged or even partially destroyed, allowing gases and high-temperature particles to reach other cells. To prevent this, a portion of the spacer element, such as a heat capacity layer, a heat conduction layer, another layer, or a combination of these layers, of the spacer extends to contact the interior surface of the housing, including one or more of the sidewalls, top or bottom surfaces. The spacer may include a layer, such as a heat capacity layer, made of a metal or a high-temperature polymer that can withstand the expected temperature of the gases and particles. Thus, when a portion of the spacer element, such as a heat capacity layer, a heat conduction layer, another layer, or a combination of these layers, extends into the interior of the housing, it acts as a barrier that can prevent heat transfer, overheating, or damage to nearby battery cells.

[0263] FIG. 22 illustrates an embodiment of a spacer element including a layer that extends beyond the dimensions of the battery cells relative to the housing. A battery module 2200 includes multiple battery cells 2210 separated by spacer elements 2220. The spacer elements may comprise a heat capacity or thermally conductive layer 2220b sandwiched between an insulating layer 2220c and a sacrificial material layer 2220a. The heat capacity or thermally conductive layer 2220b extends away from the insulation and contacts the inner surface of the housing 2230, forming a barrier between adjacent battery cells 2210. Hot gases and particulate matter expelled from a partially ruptured battery cell during a thermal runaway event are contained by the heat capacity or thermally conductive layer 2220b from the spacer elements, making a thermal runaway event from one battery cell less likely to cause thermal runaway in other battery cells within the module.

[0264] Extending the spacer element layer to the inner surface of the housing, including one or more of the sidewalls, top, or bottom of the inner surface of the housing, can create "compartments" that isolate the battery cells from each other. Referring to FIG. 22 , a thermally capacitive or thermally conductive layer 2220b extends from adjacent spacers to the inner surface of the housing 2230, forming compartments 2250 that at least partially surround the battery cells. Such compartments can contain hot gases and particulate matter extruded from the battery cells. Containment of hot gases by the compartments 2250 formed by the spacer elements can create stress within the module due to increased pressure within the compartment when the hot gases are released by the battery cells 2210. To further mitigate potential damage to the battery module, one or more vent ports 2260 can be formed in the housing. The vent ports can be located in any portion of the housing, including the sidewalls (shown in FIG. 22 ) or the top or bottom of the housing. The vent ports can be openings or pressure relief valves.

[0265] Manufacturing tolerances for battery modules and battery packs can vary. Therefore, it can be difficult to determine the exact length of the extension of the heat capacity layer that needs to contact the inner wall of the housing. In some embodiments, the heat capacity layer can bend, such that a portion of the heat capacity layer bends or deflects when contacting the inner surface of the housing. In some embodiments, the heat capacity layer can deform and form a restored shape before installation. For example, an end region of the portion of the heat capacity layer or thermally conductive layer that extends beyond the insulating layer can bend, bend, or otherwise deform to provide a resilient shape configured to contact the inner surface of the module wall and to provide a barrier or seal against contacting gases and / or particulate matter. The resilient heat capacity layer or thermally conductive layer can be positioned to allow movement or compression of a portion of the housing during module manufacturing.

[0266] In exemplary embodiments, the spacer element may include a metal component, such as a metal layer (e.g., stainless steel, aluminum, titanium, nickel, steel, iron, or a combination thereof) extending from an insulating layer to provide a barrier or seal against gases and / or particulate matter. The metal component may be an extension of a heat capacity layer, a heat conduction layer, or may be a separate component of the spacer element. Portions of the metal component may be curved, bent, or otherwise deformed to provide a resilient shape configured to contact the interior surface of the module wall and to provide a barrier or seal against gases and / or particulate matter. Examples of these embodiments are shown in FIGS. 18-21. When the spacer element is installed, the extension of the metal component (i.e., the component extending away from the insulating layer) contacts and deflects against the interior surface of the housing. This allows the metal component to contact the interior of the housing and form a seal without having to be formed to the exact dimensions required.

[0267] FIG. 18A illustrates an embodiment of a spacer element 1820 having an extended heat capacity or thermally conductive layer 1820b sandwiched between insulating layers 1820a. The insulating layers can be encapsulated by an encapsulation layer 1820c, as shown. In this embodiment, a portion of the heat capacity or thermally conductive layer 1820b extends beyond the insulating layers to form an extension 1822. The extension 1822 can be formed along one or more of the sides of the spacer element, such as along the top and sides of the spacer element, as shown. Creases or folds 1824 are formed on the extension to allow the extension to resiliently deflect. During use, the spacer element is placed between battery cells, and the extension 1822 contacts the inner surface of the housing, forming a seal between the spacer element and the inner surface 1830, as shown in FIG. 18B. Upon contact with the inner surface of the housing, extension 1822 deflects, allowing a seal to be formed despite manufacturing dimensional variations.

[0268] FIG. 19A shows an alternative embodiment of a spacer element having extensions. The spacer element 1900 includes two heat capacity or thermally conductive layers 1920b sandwiched between insulating layers 1920a. Each of the thermally conductive or heat capacity layers extends beyond the insulating layer 1920a and branches off. This creates a Y-shaped extension 1922 that extends away from the insulating layer. As in the previous embodiment, the Y-shaped extension 1922 deflects when it contacts the inner surface 1930 of the housing, allowing a seal to form between the spacer and the housing, as shown in FIG. 19B.

[0269] FIG. 20A shows an alternative embodiment of a spacer element having extensions. The spacer element 2000 includes two heat capacity and thermally conductive layers 2020c and 2020b surrounding an insulating layer 2020a. In this embodiment, the heat capacity or thermally conductive layers 2020c and 2020d can serve as encapsulation layers for the spacer element. As in the previous embodiment, the heat capacity or thermally conductive layers 2020b can be present between the insulating layers 2020a. Each of the thermally conductive or heat capacity layers 2020c and 2020d extends beyond the insulating layer 2020a and branches off from it, creating a pair of branches of extensions 2022a and 2022b that extend away from each other. As in the embodiment of FIG. 19, extensions 2022a and 2022b deflect when they contact the inner surface 2030 of the housing, allowing a seal to be formed between the spacer element and the housing, as shown in FIG. 20B.

[0270] FIG. 21A illustrates a modified extension applicable to any of the embodiments disclosed herein, particularly those illustrated in FIGS. 18A, 18B, 19A, 19B, 20A, and 20B. Similar to FIGS. 20A and 20B, the spacer element 2100 includes two heat capacity or thermally conductive layers 2120c or 2120d surrounding an insulating layer 2120a. The heat capacity or thermally conductive layer 2120b may be present between the insulating layers 2120a. Each of the thermally conductive or heat capacity layers 2120c and 2120d extends beyond the insulating layer 2120a and branches away from each other, creating a pair of branches of extensions 2122a and 2122b that extend away from each other. In this embodiment, the extensions 2122a and 2122b include rounded ends 2124a and 2124b, respectively. The rounded ends allow the extensions to more easily slide against the housing inner surface 2130 during installation and use. As in the embodiment of Figure 20B, extensions 2122a and 2122b deflect when they contact the housing inner surface 2130, allowing a seal to form between the spacer element and the housing, as shown in Figure 21B.

[0271] 23, each of the battery cells 2310 is adjacent to a first spacer element 2320a and a second spacer element 2320b, with a portion 2322a of the first spacer element extending above and over the top surface of the battery cell 2310. The portion 2322a of the first spacer element that extends over the top surface of the battery cell contacts the extension 2322b of the second spacer element. In this manner, an embodiment of a spacer element, or portion of a spacer element, can cover one battery cell and at least partially isolate it from the other battery cell.

[0272] The passage of hot gases and particles from the battery cells into the spacer element region can cause a large amount of heat buildup. Heat can build up in this area because the barrier element is designed to keep the heat contained around the defective battery cell, away from the other battery cells. The abnormally high temperatures and explosive particles can affect the integrity of the enclosure, particularly the top or sidewalls of the enclosure. To protect the interior of the enclosure, the enclosure can be protected with a thermal barrier. This barrier can be made of heat-resistant and flame-retardant materials, such as mica, microporous silica, ceramic fibers, mineral wool, aerogel materials, and metals. The enclosure can also include features configured to control or direct the flow of effluent, i.e., gas and particulate material, emitted from the battery cells. These features, such as baffles, protrusions, channels, flaps, extensions, or combinations thereof, can be formed from or coated with thermally protective, refractory, or insulating materials and composites thereof, such as aerogel, aerogel composites, mica, microporous silica, ceramic fibers, mineral wool, metals, combinations thereof, or materials that include these thermally insulating, refractory, or insulating materials.

[0273] In another embodiment, the spacer elements contact the edge elements, forming a seal between the spacer elements and the housing. Figure 24 shows an embodiment in which separate edge elements 2415 are placed along the housing wall in locations proximate to the expected locations of the spacer elements 2410. The use of separate edge elements allows the portion of the housing proximate the battery cells to remain open, allowing electrical connections to be made to the battery cells without having to pass through the edge elements. The separate edge elements have a width slightly larger than that of the spacer elements to allow for differences in manufacturing tolerances.

[0274] FIGS. 25A-25B illustrate embodiments of edge elements 2415 used to form a seal between a spacer element and the interior of a housing. In FIG. 25A, the edge element is shown positioned on the interior surface of the housing. The spacer element ("C2C barrier") is positioned between adjacent battery cells. As shown in FIG. 25B, during positioning of the spacer element, one or more resilient members 2430 deflect to receive the spacer element. Contact between the resilient members and the spacer element can form a barrier against gases and particles extruded from battery cells experiencing thermal runaway. As shown in FIG. 25B, by making the edge element wider than the spacer element, there is some lateral tolerance for the position of the spacer relative to the edge element. In some embodiments, the edge element includes a portion that extends in a direction parallel to the edge of the spacer element, thereby forming a seal against the side of the spacer element along the length of the edge of the spacer element.

[0275] Although the edge elements are shown as separate elements attached to the interior wall of the housing, it should be understood that the edge elements may be attached to or be extensions of the spacer elements. In this embodiment, when the spacer elements are installed and contact the interior surface of the housing, the resilient elements of the edge elements deflect.

[0276] In some embodiments, insulating material 2450 can be positioned between separate edge elements. Insulation between the edge elements and adjacent battery cells can help prevent heat and particle flow to adjacent battery cells.

[0277] As previously described, the edge elements can be formed from heat-resistant and flame-retardant materials. The edge elements can also be comprised of an expansion material. In addition to using expansion materials, shape memory materials can be used instead of or in combination with expansion materials. Shape memory materials are characterized by the ability to recover to their original shape from a state of apparent substantial plastic deformation when subjected to a specific stimulus. This is known as the shape memory effect (SME). Examples of shape memory materials include, but are not limited to, copper-aluminum-nickel alloys and nickel-titanium alloys (e.g., nitinol).

[0278] For example, shape memory edge elements can be used to enclose sections within a module. Referring to FIGS. 26A and 26B, shape memory edge element 2622 includes a fold that, when triggered by heat, moves quickly upward (as shown in FIG. 26B). The raised portion blocks high temperatures, fire, and thermally runaway materials, preventing heat propagation between cells. In the embodiment shown in FIGS. 26A and 26B, the shape memory edge element is positioned so that the raised portion blocks areas prominently indicated by AA, such as where thermal runaway is likely to occur. In addition to containing thermal events in area AA, additional thermal management elements can be included. For example, within area AA, an expanding thermal barrier layer 2642 can be incorporated between cells or at any desired location within the module. These expanding thermal barrier layers 2642, when activated by inducing a thermal event, can expand outward from the inner layers of the battery case, blocking heat and mass transfer and further defeating the purpose of the shape memory edge element 2622, which is to contain thermal runaway material in region AA.

[0279] In another embodiment, instead of containing the thermal event within an area, a barrier is formed in response to a triggered temperature that blocks the diffusion of heat, fire, and thermally runaway materials. Referring to Figures 26C and 26D, shape memory edge elements 2623a and 2623b are positioned between two battery cells in a manner that causes 2623a and 2623b to jerk upward in two different directions, preventing the passage of heat, fire, and thermally runaway materials.

[0280] Shape memory materials and expansion materials can also be used together in elements to prevent heat, fire, and thermal runaway material diffusion within a module. Referring to FIGS. 27A and 27B, an embodiment is shown in which shape memory materials and expansion materials are layered to create edge elements 2722. Specifically, an expansion gasket can be positioned between battery cells within a module. A shape memory cap is attached to the top of the expansion gasket. As shown in FIG. 27B, upon a heat-triggering event, the expansion material expands and the shape memory cap bends outward, completing the barrier cap between the cells. In another embodiment, shown in FIGS. 27C and 27D, a shape memory material 2723 is fixed to the interior layer of the module case, while an expansion material 2721 is sandwiched between the cells. Upon a heat-triggering event, the expansion material 2721 is free to expand and carbonize, causing the shape memory material 2723 to bend downward toward the expanding expansion material 2721, creating a barrier.

[0281] In some embodiments, shape memory materials can be used in conjunction with a cooling system, such as a cooling plate. During normal charging and discharging operations, the shape memory material (i.e., typically an alloy) conducts heat away from the battery cells to a cooling system, such as a cooling plate. The thermal barrier between the battery cells of the module acts as a buffer layer, accommodating the volumetric changes of the cells during charging and discharging events. In the event of thermal runaway, the use of shape memory materials can create distance between the battery cells and the thermal barrier (e.g., foam / aerogel), allowing heat to be better conducted to the cooling system (i.e., causing a reduction in the amount of heat received by the thermal barrier).

[0282] For example, referring to FIGS. 28A and 28B , a portion 2800 of a module is shown in which two battery cells 2810 are separated by a thermal barrier layer 2820. The battery cells 2810 and the thermal barrier layer are in thermal contact with a cooling system 2830 (e.g., a cooling plate). To protect the thermal barrier layer 2820, a shape memory plate 2840 is sandwiched between the battery cells 2810 and the thermal barrier layer 2820. The shape memory plate 2840 is also in contact with the cooling system 2830. When a thermal triggering event (shown in FIG. 28B ) occurs, the shape memory plate 2840 bends to create a separation between the battery cells 2810 and the thermal barrier layer 2820. Heat radiated from the high temperature at the battery cells 2810 (i.e., heat resulting from the triggering event) is conducted to the curved shape memory plate 2840 and then conducted to the cooling system 2830, thereby reducing the heat transferred to the barrier layer.

[0283] In another embodiment, a shape memory material element can be combined with a thermally conductive layer. The shape memory material element can be a heat-activated spring that pushes the conductive material away from the battery cell experiencing a heating-triggering event. Referring to FIGS. 29A, 29B, and 29C, a module portion 2900 can include battery cells 2910 connected to a cooling system 2930. A thermal barrier layer 2920 having a protective thermally conductive layer 2950 disposed on its interface surface is sandwiched between the battery cells 2910. The thermally conductive layer 2950 can be formed from any conductive metal or alloy, such as aluminum or copper. A shape memory material element 2955 is disposed across the thermally conductive layer 2950 (shown in FIG. 29C). When a thermally triggering event (shown in FIG. 29B) occurs, the shape memory element 2955 (e.g., a spring) expands and pushes the thermally conductive layer 2950 away from the battery cell experiencing the heating-triggering event. The thermally conductive layer 2950 is pressed toward the thermal insulation layer 2920, and the thermally conductive layer 2950 may be formed from a compressible material (e.g., foam, aerogel, etc.) that can accommodate a change in volume and allow for the formation of a barrier space between the battery cell 2910 and the thermal insulation layer 2920.

[0284] When forming a barrier between battery cells, the spacer elements are positioned to prevent direct transfer of hot gases and particles between the cells. The spacer elements, in some embodiments, can still transfer heat between cells through thermal conduction paths, especially when metal or some other thermally conductive material is positioned in the spacer. To prevent conductive heat transfer through or around the spacer elements, intentional thermal breaks can be installed in the thermally conductive material of the spacer. These thermal breaks can interrupt the transfer of heat through the spacer elements. Similarly, thermal breaks can be formed in edge elements to prevent conductive heat transfer. In some embodiments, an additional layer of insulating material is positioned adjacent to the thermally conductive material, for example, between the thermally conductive material and an adjacent cell or cells. In such embodiments, the additional layer of insulating material prevents, limits, or interrupts conductive heat transfer through or around the thermal spacer elements.

[0285] While the methods, systems, and devices disclosed above are suitable for creating a barrier between battery cells, the corner areas of the housing may, in some variations, be free of any insulating material. In some embodiments, insulating elements may be installed in the corners of the housing cover / lid. During assembly, the insulating elements fill a portion of the corners of the housing, providing an additional thermal barrier and / or a barrier to prevent the flow of gases and particulates that may be expelled from the cells. The insulating elements may be compressible or rigid. In one embodiment, the insulating elements may be in the form of rods that are compressed when the cover is installed on the housing. If the rods are compressible, they expand and fill the corner spaces when their tops are installed on the housing. Alternatively, ridges may be formed in the corners of the top, which form a seal when the top is installed on the housing.

[0286] The various battery modules described herein can be used in energy storage systems. Energy storage systems can include one or more battery modules. The thermal and particulate barriers of the described battery modules reduce the incidence of an entire battery module experiencing thermal runaway. Thus, the disclosed embodiments can prevent catastrophic failure of the energy storage system. The disclosed battery modules can be used in vehicle electrical storage systems. The reduced chance of thermal runaway makes the disclosed battery modules safer for many types of vehicles, particularly automobiles, aircraft, and spacecraft.

[0287] Certain U.S. patents, U.S. patent applications, and other materials (e.g., articles) are incorporated by reference in this patent. However, the text of such U.S. patents, U.S. patent applications, and other materials is incorporated by reference only to the extent that no conflict exists between such text and the other claims and drawings set forth herein. In the event of such a conflict, any such conflicting text so incorporated by the referenced U.S. patents, U.S. patent applications, and other materials is specifically not incorporated by reference in this patent.

[0288] Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It should be understood that the forms of the invention shown and described herein are to be considered as examples of multiple embodiments. Elements and materials may be substituted for those shown and described herein, and components and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to those skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as set forth in the following claims. Some of the embodiments of the invention related to the present invention are shown below. [Embodiment 1] A battery module, an enclosure including an interior surface defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the spacer elements including at least one heat capacity layer and at least one insulating layer; the battery module, wherein a portion of each of the spacer elements extends away from the insulating layer and contacts the inner surface of the housing such that a thermal barrier is formed between adjacent battery cells. [Embodiment 2] 2. The module of embodiment 1, wherein the two or more battery cells are oriented vertically parallel to the end plates, and the spacer elements contact at least one of the bottom surface, top surface, first sidewall, and second sidewall to form the thermal barrier between adjacent battery cells. [Embodiment 3] 3. The module of embodiment 1 or 2, wherein each of the spacer elements contacts one or more channels formed on and / or in the inner surface. [Embodiment 4] A module as described in embodiment 3, wherein the one or more channels protrude from one or more of the first end plate, the second end plate, the first side wall, the second side wall, the top plate, and the bottom plate. [Embodiment 5] The module of embodiment 3, wherein the one or more channels are recesses in one or more of the first end plate, the second end plate, the first side wall, the second side wall, the top plate, and the bottom plate. [Embodiment 6] 6. The module of any one of embodiments 3 to 5, wherein each of the spacer elements contacts one or more portions of the channel forming a seal between the spacer element and the inner surface. [Embodiment 7] 7. The module of any one of embodiments 3 to 6, wherein the one or more channels are substantially U-shaped with opposing sidewalls and a bottom. [Embodiment 8] 8. The module of embodiment 7, wherein the spacer elements contact the side walls of the U-shaped channels. [Embodiment 9] 9. The module of embodiment 8, wherein a gap exists between the spacer element and the bottom surface of the U-shaped channel. [Embodiment 10] 10. The module of any one of claims 1-9, wherein the insulating layer has a thermal conductivity through a thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C. [Embodiment 11] 11. The module of embodiment 10, wherein the insulating layer comprises an aerogel. [Embodiment 12] 13. The module of any one of embodiments 1 to 12, wherein the heat capacity layer contacts at least one of the bottom surface, the top surface, the first sidewall, or the second sidewall. [Embodiment 13] A module described in any one of embodiments 1 to 12, wherein the one or more spacer elements further include an exterior covering the at least one heat capacity layer and at least one insulating layer, the exterior including at least one sacrificial layer and at least one encapsulating material layer. [Embodiment 14] 14. The module of embodiment 13, wherein the at least one sacrificial material layer comprises a compressible pad having a compressive force deflection of 25% at about 27 kPa to about 55 kPa. [Embodiment 15] 15. The module of embodiment 13 or 14, wherein the at least one encapsulant layer comprises a polymer. [Embodiment 16] A module described in any one of embodiments 1 to 15, wherein the one or more spacer elements and the inner surface of the housing are configured together to define a plurality of separate compartments, and one battery cell is placed in each compartment. [Embodiment 17] 17. The module of embodiment 16, wherein at least a portion of the housing comprises one or more ventilation ports, the one or more ventilation ports being fluidly coupled to one or more of the plurality of separate compartments. [Embodiment 18] 18. The module of embodiment 17, wherein one or more of the vent ports is a pressure relief valve. [Embodiment 19] 19. A module as described in embodiment 17 or 18, wherein one or more of the ventilation ports comprises an opening formed in a portion of the housing. [Embodiment 20] A module described in any one of embodiments 17 to 19, wherein one or more of the ventilation ports are located on a side wall or top plate of the housing that communicates with one or more of the compartments. [Embodiment 21] A battery module, an enclosure including an interior surface defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the spacer elements including at least one heat capacity layer and at least one insulating layer; a plurality of discrete edge elements disposed along an inner surface of the housing, the edge elements being compressible and comprising a material having an onset temperature of chemical decomposition greater than about 100°C; each of the spacer elements contacts one of the plurality of discrete edge elements, thereby forming a seal by the edge elements between the spacer elements and the interior surface of the housing that thermally isolates the adjacent battery cells; The battery module. [Embodiment 22] 22. The module of embodiment 21, wherein the edge element comprises an expansion material, a shape memory material, or a combination of an expansion material and a shape memory material. [Embodiment 23] 22. The module of embodiment 21, wherein the edge element comprises a silicone polymer. [Embodiment 24] 22. The module of embodiment 21, wherein the edge elements include one or more capacitive layers and one or more insulating layers. [Embodiment 25] 22. The module of embodiment 21, wherein the edge element comprises a portion of the at least one heat capacity layer of the spacer element. [Embodiment 26] 22. The module of embodiment 21, wherein the edge element comprises a portion of the at least one insulating layer of the spacer element. [Embodiment 27] 27. The module of embodiment 26, wherein the edge element further includes an exterior covering the one or more capacitive layers and the one or more insulating layers, the exterior including at least one compressible layer. [Embodiment 28] 27. The module of embodiment 26, wherein the compressible layer has a compressive force deflection of 25% at about 27 kPa to about 55 kPa. [Embodiment 29] A module described in any one of embodiments 21 to 28, wherein the two or more battery cells are oriented parallel to the end plate between the first side wall and the second side wall, the spacer element contacts the bottom surface, and one of the one or more edge elements is positioned between the spacer element and the top surface. [Embodiment 30] 30. The module of embodiment 29, wherein one of the one or more edge elements is positioned between the first side wall and the spacer element and / or the second side wall and the spacer element. [Embodiment 31] 30. The module of embodiment 29, wherein the spacer element contacts the first sidewall and the second sidewall. [Embodiment 32] 32. The module of embodiment 31, wherein each of the spacer elements contacts one or more channels formed in the first sidewall and the second sidewall. [Embodiment 33] 33. The module of embodiment 32, wherein the one or more channels are recesses in the first sidewall and / or the second sidewall. [Embodiment 34] 33. The module of embodiment 32, wherein the one or more channels protrude from the first side wall and / or the second side wall. [Embodiment 35] 35. The module of any one of embodiments 32 to 34, wherein each of the spacer elements contacts one or more portions of the channel forming a seal between the spacer element and the inner surface. [Embodiment 36] 35. The module of any one of embodiments 32 to 34, wherein the one or more channels are substantially U-shaped with opposing sidewalls and a bottom. [Embodiment 37] 37. The module of embodiment 36, wherein the spacer element contacts the sidewall of the U-shaped channel. [Embodiment 38] 38. The module of embodiment 37, wherein a gap exists between the spacer element and the bottom surface of the U-shaped channel. [Embodiment 39] 39. The module of any one of claims 21 to 38, wherein the insulating layer of the spacer element has a thermal conductivity through a thickness dimension of the insulating layer of less than about 50 mW / m·K at 25°C and less than about 60 mW / m·K at 600°C. [Embodiment 40] 40. The module of embodiment 39, wherein the insulating layer of the spacer element comprises aerogel. [Embodiment 41] A module as described in embodiment 39 or 40, wherein the one or more spacer elements further include an exterior covering the at least one heat capacity layer and at least one insulating layer, the exterior including at least one sacrificial layer and at least one encapsulating material layer. [Embodiment 42] 42. The module of embodiment 41, wherein the at least one sacrificial material layer comprises a compressible pad having a compressive force deflection of 25% at about 27 kPa to about 55 kPa. [Embodiment 43] 43. The module of embodiment 41 or 42, wherein the at least one encapsulant layer comprises a polymer. [Embodiment 44] A module described in any one of embodiments 21 to 43, wherein the one or more spacer elements, the one or more edge elements, and the inner surface of the housing are configured together to define a plurality of separate compartments, and one battery cell is disposed in each compartment. [Embodiment 45] 45. The module of embodiment 44, wherein at least a portion of the housing comprises one or more ventilation ports, the one or more ventilation ports being fluidly coupled to one or more of the plurality of separate compartments. [Embodiment 46] 46. ​​The module of embodiment 45, wherein one or more of the ventilation ports is a burst disk. [Embodiment 47] 47. A module as described in embodiment 45 or 46, wherein one or more of the ventilation ports comprises an opening formed in a portion of the housing. [Embodiment 48] A module described in any one of embodiments 45 to 47, wherein one or more of the ventilation ports are located on a side wall or top plate of the housing that communicates with one or more of the compartments. [Embodiment 49] A battery module, an enclosure including an interior surface defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the spacer elements including at least one heat capacity layer and at least one insulating layer; one or more extensions extending from the spacer element, the extensions being substantially elastic; The one or more extensions deflect to form a seal between the spacer element and the housing. [Embodiment 50] A battery module, a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer; one or more extensions extending from the one or more spacer elements, the one or more extensions being formed from a thermally active material; The one or more extensions deflect to form a seal between the spacer element and the housing. [Embodiment 51] 51. The battery module of embodiment 50, wherein the thermally active material comprises a shape memory material. [Embodiment 52] 52. The battery module of embodiment 51, wherein the shape memory material is a shape memory alloy. [Embodiment 53] 51. The battery module of embodiment 50, wherein the thermally active material comprises an expansion material. [Embodiment 54] 51. The battery module of embodiment 50, wherein the thermally active material comprises a combination of a shape memory material and an expansion material. [Embodiment 55] 55. The battery module of any one of embodiments 50 to 54, wherein the one or more extensions, when deflected, create an area within the battery module that is sealed from the remainder of the battery module. [Embodiment 56] 55. The battery module of any one of embodiments 50 to 54, wherein the one or more extension portions include a first extension portion and a second extension portion, and the first extension portion is biased in an orientation opposite to that of the second extension portion. [Embodiment 57] A battery module, a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer; one or more extensions extending from the inner surface of the housing, the one or more extensions being formed from a thermally active material; The one or more extensions deflect to form a seal between the spacer element and the housing. [Embodiment 58] 58. The battery module of embodiment 57, wherein the thermally active material is a shape memory material. [Embodiment 59] 58. The battery module of embodiment 57, wherein the thermally active material is a combination of a shape memory material and an expansion material. [Embodiment 60] 58. The battery module of embodiment 57, wherein the one or more spacer elements comprise aerogel. [Embodiment 61] 58. The battery module of embodiment 57, wherein the one or more spacer elements comprise an expansion material. [Embodiment 62] A battery module, a housing including an interior surface and enclosing an interior space therein; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the one or more spacer elements including at least one insulating layer in physical contact with at least one thermally conductive layer including a shape memory material; the shape memory material of the at least one conductive layer deflects in response to thermal activation to form a gap between the spacer element and at least one of the two or more battery cells. [Embodiment 63] 63. The battery module of embodiment 62, wherein the shape memory material comprises nitinol. [Embodiment 64] 63. The battery module of embodiment 62, wherein the shape memory material is in the form of a plate. [Embodiment 65] 63. The battery module of embodiment 62, wherein the shape memory material is dispersed throughout the at least one thermally conductive layer. [Embodiment 66] 66. The battery module of embodiment 65, wherein the shape memory material is in an expanded spring form when activated by heating. [Embodiment 67] 66. The battery module according to any one of embodiments 62 to 65, further comprising a cooling system in thermal contact with the two or more battery cells. [Embodiment 68] 68. The battery module of embodiment 67, wherein the cooling system is a cooling plate. [Embodiment 69] An electric energy storage system comprising a plurality of battery modules according to any one of embodiments 1 to 68. [Embodiment 70] A device or vehicle comprising the electrical energy storage system described in embodiment 69.

Claims

1. A battery module, an enclosure including an interior surface defined by first and second end plates extending between first and second side walls and between a top plate and a bottom plate; two or more battery cells disposed in the interior space of the housing; one or more spacer elements disposed between adjacent battery cells, each of the spacer elements including at least one heat capacity layer and at least one insulating layer; the insulating layer has a thermal conductivity through a thickness dimension of the insulating layer of less than 50 mW / m·K at 25° C. and less than 60 mW / m·K at 600° C.; the battery module, wherein a portion of each of the spacer elements extends away from the insulating layer and contacts the inner surface of the housing such that a thermal barrier is formed between adjacent battery cells.

2. 2. The module of claim 1, wherein the two or more battery cells are oriented longitudinally parallel to the first end plate and the second end plate, and the one or more spacer elements contact at least one of the bottom plate, the top plate, the first sidewall, and the second sidewall to form the thermal barrier between adjacent battery cells.

3. The module of claim 1 , wherein each of the one or more spacer elements contacts one or more channels formed on and / or in the interior surface.

4. 4. The module of claim 3, wherein the one or more channels protrude from one or more of the first end plate, the second end plate, the first side wall, the second side wall, the top plate, and the bottom plate.

5. 4. The module of claim 3, wherein the one or more channels are recesses in one or more of the first end plate, the second end plate, the first side wall, the second side wall, the top plate, and the bottom plate.

6. The module of claim 3 , wherein each of the one or more spacer elements contacts one or more portions of the channel forming a seal between each of the one or more spacer elements and the interior surface.

7. The module of claim 3 , wherein the one or more channels are substantially U-shaped with opposing sidewalls and a bottom.

8. The module of claim 7 , wherein each of the one or more spacer elements contacts the sidewall of the U-shaped channel.

9. The module of claim 8 , wherein a gap exists between the spacer element and the bottom surface of the U-shaped channel.

10. The module of claim 1 , wherein the insulating layer comprises an aerogel.

11. The module of claim 1 , wherein the heat capacity layer contacts at least one of the bottom plate, the top plate, the first sidewall, or the second sidewall.

12. 10. The module of claim 1, wherein the one or more spacer elements further include an exterior covering the at least one heat capacity layer and the at least one insulating layer, the exterior including at least one sacrificial layer and at least one encapsulating material layer.

13. The module of claim 12 , wherein the at least one sacrificial layer comprises a compressible pad having a compressive force deflection of 25% between 27 kPa and 55 kPa.

14. The module of claim 12 , wherein the at least one encapsulant layer comprises a polymer.

15. The module of claim 1 , wherein the one or more spacer elements and the inner surface of the housing are configured together to define a plurality of separate compartments, one battery cell disposed in each compartment.

16. 16. The module of claim 15, wherein at least a portion of the housing comprises one or more vent ports, the one or more vent ports fluidly coupled to one or more of the plurality of separate compartments.

17. 17. The module of claim 16, wherein one or more of the vent ports is a pressure relief valve.

18. The module of claim 16 , wherein one or more of the vent ports comprises an opening formed in a portion of the housing.

19. The module of claim 16 , wherein one or more of the vent ports are located in a sidewall or top plate of the housing that communicates with one or more of the compartments.

20. An electrical energy storage system comprising a plurality of battery modules according to any one of claims 1 to 19.

21. 21. A device or vehicle comprising the electrical energy storage system of claim 20.

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