Silicone-based thermal insulation material for battery modules

Abstract

Silicone-based thermal insulation material for battery modules Metal ion battery modules and battery packs for electric vehicles are sprayable, thixotropic, and contain an addition-curable or moisture-curable ceramizable organosilicon composition containing 50-85 wt. % of an aluminum trihydrate-containing filler, in an amount such that the aluminum trihydrate is present in an amount of at least 30 wt. % based on the weight of the organosilicon composition, which significantly reduces heat transfer to the area above the battery module or battery pack when the top metal cover of the battery module or battery pack is coated on the side of the cover facing the battery module or individual battery cells.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 419,615, filed October 26, 2022, the disclosure of which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present invention is directed to an improved battery module suitable for applications requiring large amounts of electrical energy, such as electric vehicle batteries. 2. Description of Related Art

[0003] Lead-acid batteries were widely used in the past when a rechargeable method for storing electrical energy was desirable. However, these batteries have well-known drawbacks. These include a relatively low energy density due to their large mass, the use of environmentally undesirable lead, and, most obviously, the presence of very strong sulfuric acid. Nickel-cadmium batteries improved storage density but were relatively expensive. Their applications were primarily limited to power tools and commercial electrical appliances. Furthermore, the energy storage density of nickel-cadmium batteries is still not as high as desired. In recent years, lithium-ion batteries have been used in a variety of applications due to their high energy storage capacity, including powering electric vehicles, which was not possible with lead-acid batteries due to their heavy weight.

[0004] Lithium-ion batteries employed in large-scale applications such as electric vehicles are not manufactured as single cells, but as individual canisters or "cells" that are then assembled into modules. The cells can be cylindrical, rectangular, or any unique shape. An electric vehicle "battery" can consist of one or more such modules electrically connected together. While these modules can be a single large module consisting of multiple individual cells, it is currently common to assemble multiple such modules to form a "battery pack." These battery packs include at least a frame containing the modules, a top cover, and a bottom cover. Depending on the design and other characteristics of the vehicle, such as whether it is an all-electric vehicle, an electric / gasoline hybrid vehicle, an electric-powered aircraft, or an industrial vehicle such as a "hi-lo," the battery pack may also include additional elements such as reinforcing ribs. Additionally, a "module" may consist of a space with a frame or compartment containing multiple individual cells, rather than a free-standing structure assembled into a battery pack.

[0005] Lithium-ion batteries, however, are one type of modern, rechargeable, high-energy-density ion battery that can be used in applications such as those described above. Because nearly all of these battery types contain active elements, such as lithium, sodium, or aluminum, they are potentially flammable. For example, lithium-ion batteries have been known to occasionally catch fire, leading to their being banned in checked baggage on airplanes. When such batteries are used in electric vehicles, the potential for fires increases because the vehicle may be involved in an incident in which the integrity of the battery pack or individual battery modules is compromised. This type of fire is even more dangerous because water, commonly used in firefighting, can increase the energy released. Clearly, limiting the amount of energy released during a fire is desirable, not only to protect vehicle occupants but also to protect and prevent combustion of other flammable components in the electric vehicle. Top and bottom covers of the battery pack provide some degree of protection. However, these covers cannot be made extremely thick without significantly increasing weight, and even if thick covers were possible, they are constructed of metal, which provides little impediment to heat conduction. While many potential thermal insulation materials exist, such as those based on pyrogenic silica, these fillers are difficult to employ in industrial environments and are prone to releasing large amounts of silica particles in the event of an emergency. Many other insulating materials are either expensive to manufacture or apply, or cannot withstand the high temperatures that would be encountered. Therefore, it would be desirable to provide an economical means of thermally insulating a vehicle and its surroundings in the event of a battery pack fire.

[0006] U.S. Patent No. 9,507,054 discloses a highly reflective and flame-retardant silicone composition comprising a silicone resin, an organosilicon compound, aluminum hydroxide as a flame retardant, typically present in an amount up to 45% by weight, and a reflective filler containing titanium dioxide. The composition has a very high viscosity and is suitable for forming articles by processes such as injection molding, transfer molding, casting, extrusion, overmolding, compression molding, or cavity molding. The high viscosity of such a compound precludes its economical use as a thermal insulator in lithium-ion batteries. Furthermore, the relatively low amount of aluminum hydroxide (also known as aluminum trihydrate, or "ATH") does not provide sufficient thermal stability.

[0007] German published application [WA 12106S] discloses ceramizable compositions containing up to 65% by weight of ATH. However, like the compositions disclosed in U.S. Pat. No. 9,507,054, these compositions have high viscosities, limiting their use to injection molding, casting, and press molding. Furthermore, their thermal stability may not be sufficient for demanding applications, and adding large amounts of fillers such as ATH only increases the viscosity to higher levels, making their use more complicated.

[0008] A thixotropic condensation-curable composition is known from U.S. Pat. No. 3,711,570A. The composition disclosed in the patent is a typical condensation-curable (moisture-curable) composition. In the composition, thixotropy is achieved by using emulsion-grade polyvinyl chloride particles, preferably in an amount of 5 to 50% by weight. While such compositions are thixotropic, they are also flammable and may generate toxic hydrogen chloride upon combustion. Summary of the Invention

[0009] Applicants have surprisingly and unexpectedly discovered a sprayable thixotropic crosslinkable organosilicon composition containing greater than 50 wt. % of an aluminum trihydrate-containing inorganic filler as a flame retardant and ceramic filler, a silicone thermal stabilizer, and a ceramification catalyst. The total aluminum trihydrate content in the crosslinkable organosilicon composition is a minimum of 30 wt. This composition can be applied economically and can provide a high degree of thermal insulation between battery cells and / or modules and their associated covers. The crosslinkable silicone composition may be a condensation-curable or addition-curable composition and may be used as a thermal insulator in battery modules and battery packs for applications requiring high energy storage requirements. The total aluminum trihydrate content in the crosslinkable organosilicon composition is a minimum of 30 wt. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows one embodiment of a battery pack in an "exploded" view. [Figure 2] FIG. 2 shows one embodiment of an assembled battery pack. [Figure 3] FIG. 3 shows a cross-sectional view of the battery pack of FIGS. 1 and 2, illustrating the ceramizable organosilicon composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 shows an exploded view of a generalized battery pack. In FIG. 1, battery pack 1 comprises battery modules 2 with individual battery "canisters" or "cells" 8. Electrical connections are not part of the present invention and are not shown. The modules are housed within an optional frame 4. The battery pack is surrounded on its top and bottom by top and bottom covers 5 and 6, which are fastened together with fasteners 9. Disposed between the battery modules / cells and top cover 5 is a ceramizable organosilicon composition 7 of the present invention, as shown in cross section in FIG. 3. In this case, it is shown applied to the bottom surface of the top cover and the top surface of the bottom cover.

[0012] The crosslinkable silicone composition of the present invention may be a condensation-curable composition or an addition-curable composition. Condensation-curable compositions cure in the presence of moisture, which is generally moisture naturally present in the environment, but added water or moisture may also be used to cure or accelerate the cure of the composition. An addition-curable composition in the sense of this application is a silicone composition that cures by adding silicon-bonded hydrogen to ethylenically unsaturated moieties. Those skilled in the art are aware that these compositions require the presence of a hydrosilylation catalyst.

[0013] Condensation-curable and addition-curable silicone compositions are known for their relatively high thermal stability, and are used for applications such as baking sheets and cupcake "molds" for use up to approximately 250°C. This upper use temperature limit makes crosslinked silicone compositions suitable candidates for use as base polymers for applications requiring high thermal stability. However, when such conventional compositions are highly filled, their mechanical properties deteriorate. And when such compositions are employed as thermal insulators in battery modules, they can only withstand high temperatures for a short period of time. As a result, temperatures observed on the side of the battery pack cover farthest from the battery cells or modules rapidly reach extremely high values.

[0014] The present invention provides a highly filled, sprayable, thixotropic, crosslinkable organosilicon composition. When applied to individual battery cells, modules, or battery packs, as described below, the organosilicon composition provides a high level of thermal insulation that significantly reduces heat flow from the cells or modules to areas outside the top and / or bottom covers. During a high-energy / high-temperature event, the organosilicon composition ceramizes into a thermally insulating solid rather than melting or burning. Despite the high temperatures inside the battery pack or module, the environment outside the cover does not reach 350°C for a significant period of time, preferably 8-10 minutes or more. The present invention is directed to the organosilicon composition itself, to battery packs comprising the organosilicon composition of the present invention disposed between cells, modules, silicones, and / or top and / or bottom covers surrounding the cells, modules, or battery packs, and to methods of manufacturing battery modules, battery packs, and similar structures by spraying a highly filled, crosslinkable organosilicon composition onto battery cells and / or battery modules and curing the organosilicon composition so that the cured composition is located between the active battery components and the top and / or bottom covers.

[0015] In the following text, the term "organosilicon composition" refers to the entire composition, including fillers, that is sprayed onto the components of an individual cell, battery module, or battery pack. The term "organosilicon component" refers to a compound containing tetravalent silicon with hydrogen, hydroxyl, alkoxy, and organic groups, preferably alkyl and aryl groups, bonded to the silicon atom. These organosilicon components include, but are not limited to, organosilanes, particularly alkoxysilanes, and polyorganosiloxanes, commonly referred to as "silicones." The terms "organopolysiloxane" and "polyorganosiloxane," as well as "silicone," are also synonymous herein. The term "a" in reference to a particular element, component, or step refers to one or more of such element, component, or step, unless otherwise indicated. The term "termination" is synonymous with the term "terminated" and refers to a specific chemical group or moiety located at the end of an oligomeric or polymeric polyorganosiloxane chain or chain branch, i.e., at the so-called "M" siloxy unit. The term "thixotropic" is used in the conventional sense to refer to compositions having a non-Newtonian viscosity, which decreases with increasing shear rate and increases in the absence of shear. "Sprayable" compositions can be applied by spraying or sputtering, as opposed to compositions that require the use of a stiff brush or trowel for manual application. The term "ion battery" refers to battery cells, modules, and the like that rely on the reversible transition of metals from an ionic state to a zero-valent elemental state for the purpose of storing electrical energy, including, but not limited to, lithium-ion batteries. The addition-curable and moisture-curable organosilicon compositions described herein are the same compositions used in embodiments directed to battery modules and / or battery packs, and the methods used to prepare them.

[0016] Expressions such as "disposed between the cell and / or module and the cover" mean that the organosilicon composition of the present invention is positioned between the active components of the battery, such as the battery cell and / or module, and the upper and / or lower cover, thereby enabling the organosilicon composition to insulate the areas above and / or below the module and / or battery pack from heat generated by a defective or damaged cell. Additional layers or components may be present between the upper and / or lower cover and the organosilicon composition, and / or between the cell and / or module and the organosilicon composition. In the curable composition, the listed ingredients are those added during the preparation of the composition and do not necessarily correspond to the ingredients present after storage. The terms "ATH-containing filler" and "aluminum trihydrate-containing filler" refer to a particulate inorganic filler containing ATH (aluminum trihydrate), which may contain additional particulate inorganic fillers. The ATH-containing filler does not contain any significant amount of organic fillers, such as polymer particles or polymer fibers.

[0017] In one embodiment, the present invention is directed to an electric vehicle battery assembly comprising an array or module of a plurality of individual battery cells, optionally but preferably a frame surrounding the array, a bottom cover, a top cover, and a crosslinked organosilicon composition comprising a sprayable, thixotropic, addition-curable or moisture-curable silicone composition comprising at least one polydimethylsiloxane and containing greater than 50 wt.% and less than 85 wt.% of an aluminum trihydrate-containing filler, based on the total weight of the curable silicone composition, disposed between the array or module of a plurality of batteries and the bottom cover and / or top cover. wherein the aluminum trihydrate particles of the aluminum trihydrate-containing filler comprise at least 30% by weight of an organosilicon composition, a silicone heat stabilizer, and at least one additive that promotes ceramification of the organosilicon composition upon exposure to temperatures of 600°C or greater, and wherein the crosslinked silicone composition reduces heat conduction from the side of the silicone composition closest to the array of multiple batteries to the opposing ("outer") side of the bottom cover or top cover, thereby preventing the opposing side of each cover from reaching 350°C for at least 2 minutes when the crosslinked silicone composition is exposed to a heat source having a temperature of greater than 850°C at a position 2.5 cm away from the crosslinked silicone composition.

[0018] The present invention is also directed to a battery assembly for an electric vehicle as described above, comprising a single module or a plurality of modules, each module comprising a second plurality of individual battery cells.

[0019] The present invention is further directed to an electric vehicle battery assembly as described above, wherein the sprayable thixotropic organosilicon composition is an addition-curable silicone composition of at least two components, the first component being a vinyl-functional polyorganosiloxane having a viscosity of less than 1,000 mPa·s in an amount of 20 to 70% by weight, based on the total weight of all organosilicon compounds, optionally a silanol-terminated polyorganosiloxane having a viscosity of less than 10,000 mPa·s in an amount of 20 to 40% by weight, based on the total weight of all organosilicon compounds, The first component comprises a polyorganosiloxane having a viscosity of less than 10,000 mPa·s, a silane adhesion promoter, a hydrosilylation catalyst, and, optionally, a filler; the second component comprises at least one Si-H functional crosslinker, optionally one or more optionally silanol-terminated organopolysiloxanes having a viscosity of less than 10,000 mPa·s, optionally one or more optionally silanol-terminated organopolysiloxanes having a viscosity of less than 10,000 mPa·s, optionally one or more silane adhesion promoters, and optionally a filler. At least one of the components contains a filler comprising aluminum trihydrate. The total amount of filler present in all components is 50% to 85% by weight, and a sufficient amount of aluminum trihydrate is present in the filler to provide at least 30% by weight of aluminum trihydrate based on the total weight of all components. At least one component contains a silicone thermal stabilizer, and at least one component contains an accelerator for ceramification of the organosilicon composition. At least one of the components comprises a silane adhesion promoter.

[0020] In a further embodiment of the present invention, the sprayable thixotropic organosilicon composition comprises a moisture-curable silicone composition comprising at least one silanol-terminated polyorganosiloxane having a viscosity of less than 10,000 mPa·s in an amount greater than 90 wt.%, based on the total weight of the organosilicon components of the organosilicon composition; a silicone heat stabilizer; at least one additive that promotes ceramification of the organosilicon composition; optionally, water, preferably in emulsion form, from 0.01 to 2 wt.% of an aqueous silicone emulsion containing at least about 40 wt.% water, and 50 to 85 wt.% of an aluminum trihydrate-containing filler in an amount sufficient to provide at least 30 wt.% aluminum trihydrate, based on the total weight of the organosilicon composition. The moisture-curable organosilicon composition may consist of only a single "part" or "component," e.g., a so-called "RTV-1" composition, or may comprise multiple components, preferably two components, e.g., a so-called "RTV-2" composition. The latter is preferred, with water, preferably in emulsified form, being contained in one of the two components.

[0021] The present invention is further directed to a sprayable, thixotropic, heat-resistant crosslinkable organosilicon composition comprising an addition-curable or moisture-curable silicone composition containing greater than 50 wt.% and less than 85 wt.% of an aluminum trihydrate-containing filler, based on the total weight of the curable silicone composition, sufficient to provide at least 30 wt.% aluminum trihydrate, based on the total weight of the organosilicon composition, at least one silicone heat stabilizer, and at least one additive that promotes ceramification of the organosilicon composition, wherein the crosslinkable silicone composition, after crosslinking to form a crosslinked silicone, reduces heat conduction from a side of the crosslinked silicone composition facing a metal substrate coated with the crosslinked silicone composition to an opposing surface of the metal substrate, thereby preventing the opposing side of the metal substrate from reaching a temperature of 350°C or higher for at least 2 minutes when the side of the crosslinked silicone composition facing the metal substrate is exposed to a heat source that raises the temperature of the exposed surface of the crosslinked silicone to 600°C or higher.

[0022] The present invention is further directed to a sprayable, thixotropic, multi-component, addition-curable silicone composition comprising at least two components. The first component comprises a vinyl-functional polyorganosiloxane having a viscosity of less than 1,000 mPa·s in an amount of 20-70 wt%, based on the total weight of all organosilicon components, optionally a polyorganosiloxane (preferably silanol-terminated) having a viscosity of less than 10,000 mPa·s in an amount of less than 30 wt%, based on the total weight of all organosilicon components, a silane adhesion promoter, a hydrosilylation catalyst, and optionally a filler. The second component comprises a Si-H crosslinker, optionally one or more organopolysiloxanes (preferably silanol-terminated) having a viscosity of less than 10,000 mPa·s, preferably in an amount of less than 30 wt%, based on the total weight of all organosilicon components, optionally a silane adhesion promoter, and optionally a filler. At least one component of the multi-component composition contains a filler. The total amount of this filler present in all components is 50% to 85% by weight, sufficient to provide at least 30% by weight of aluminum trihydrate based on the total weight of the organosilicon composition. At least one component contains a silicone thermal stabilizer, at least one component contains an accelerator for ceramification of the organosilicon composition at temperatures above 600°C, and at least one component contains a silane adhesion promoter. The multi-component composition is preferably a two-component composition.

[0023] The present invention is also directed to one or more, preferably one or two-component (RTV-1, RTV-2) sprayable, thixotropic, moisture-curable silicone compositions containing a silanol-terminated polyorganosiloxane having a viscosity of less than 10,000 mPa·s in an amount greater than 90 wt.%, based on the total weight of the organosilicon components; an additive that promotes ceramification of the organosilicon composition at temperatures of 600°C or greater; 0.01 to 2 wt.% aqueous silicone emulsion, preferably containing at least 40 wt.% water; a silicone heat stabilizer; and 50 to 85 wt.% aluminum trihydrate-containing filler, based on the total weight of the organosilicon composition, containing sufficient aluminum trihydrate to provide at least 30 wt.% aluminum trihydrate based on the total weight of the organosilicon composition. After curing to form a crosslinked silicone composition, the moisture-curable silicone composition reduces heat conduction from the side of the crosslinked silicone composition facing a metal substrate coated with the crosslinked silicone composition to the opposing side of the metal substrate, thereby preventing the opposing side of the metal substrate from reaching a temperature of 350°C or higher for at least 2 minutes when the side of the crosslinked silicone composition facing the metal substrate is exposed to a heat source having a temperature of 950°C at a position 2.5 cm from the surface of the crosslinked silicone composition.

[0024] The addition-curable organosilicon composition contains an organopolysiloxane having ethylenically unsaturated moieties, preferably vinyl, omega-alkenyl, alkynyl, or aryl moieties, more preferably vinyl moieties, and an organopolysiloxane containing silicon-bonded hydrogen (Si-H "moiety" or "group" or "radical," all synonymous). The addition-curable organosilicon composition also contains a hydrosilylation catalyst. In such compositions, as is well known to those skilled in the art, it is preferred that a single component not simultaneously contain ethylenically unsaturated, silicon-bonded hydrogen, and a hydrosilylation catalyst. When these three components are present simultaneously, premature crosslinking can occur. Inhibitors can be added to reduce premature crosslinking of single-component compositions, but these are only partially successful. Only a small amount of crosslinking is required before the viscosity of the composition increases to unsprayable levels.

[0025] The polyorganosiloxane having an ethylenically unsaturated portion is a linear, very lightly branched, or cyclic organopolysiloxane consisting mainly of organosiloxy units of the following formula (1): R a SiO (4-a) / 2 (1)

[0026] wherein a is 0, 1, 2, or 3, and R is a hydrocarbon or substituted hydrocarbon moiety conventionally employed in the art, such as those disclosed in paragraphs 0023-0025 of U.S. Patent Application Publication No. 2017 / 0283559 A1, which is incorporated herein by reference for this disclosure, preferably an alkyl group having 1 to 18 carbon atoms, more preferably 1 to 4 carbon atoms, and more preferably a methyl group; or an alkenyl or alkynyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms, wherein the ethylenic or ethynyl unsaturation is preferably located at the terminal end remote from the silicon atom to which the group is bonded, preferably a vinyl or allyl group, more preferably a vinyl group; an aryl, alkaryl, or arylalkyl group having 6 to 14 carbon atoms, preferably a phenyl or phenylethyl group, or a hydroxy or alkoxy group, the latter preferably having 1 to 4 carbon atoms, particularly a methoxy or ethoxy group. The hydrocarbon group may be substituted with non-interfering substituents such as halogen or cyano groups, although this is not preferred. In the majority of organosiloxy units of formula (1), the units are D units, where a is 2.

[0027] The polyorganosiloxanes containing ethylenically unsaturated moieties, whether linear or slightly branched, are terminated with so-called M groups of formula (2). R 1 3SiO 1 / 2 (2)

[0028] In the formula, each R 1 may be the same or different and have the definition of R. 1is preferably selected from methyl or vinyl. The most preferred M terminal units are trimethylsiloxy and vinyldimethylsiloxy units. The most preferred polyorganosiloxanes having ethylenically unsaturated moieties are polydimethylsiloxanes having vinyldimethylsiloxy terminal units. Also preferred are polyorganosiloxanes whose repeating units comprise units of formula (1) in which one R is an unsaturated hydrocarbon, preferably vinyl, and the other R is a saturated or aromatic hydrocarbon, preferably methyl. In this case, the terminal groups may or may not also contain ethylenically unsaturated groups.

[0029] The polyorganosiloxane containing ethylenically unsaturated groups must contain an average of at least two such groups. Furthermore, the polyorganosiloxane containing ethylenically unsaturated groups must have a viscosity of less than 1,000 mPa·s, and such that the overall organosilicon composition, including the filler, is both thixotropic and sprayable. Thixotropy may be assessed by standard Brookfield viscosity measurements using a rotary cone-and-plate viscometer, such as those available from AMETEK or BYK-Gardner GmbH. Measurements may be performed, for example, at 0.1 s. -1 , 1 second -1 , 10 seconds -1 The shear rate may be increased by, but not limited to, several different shear rates, such as, but not limited to, the above. By noting the apparent relatively large viscosity increase at low rotation speeds, it is possible to increase the shear rate by even higher shear rates (e.g., 192 s -1 ) Thixotropic behavior can also be demonstrated. In the past, it was often 4 seconds -1 and 20 seconds -1The viscosity measurements were compared and used to calculate a "thixotropy index." The degree of thixotropy required may vary somewhat depending on the construction of each battery, but preferably is sufficient to allow the organosilicon composition to quickly assume a gel- or solid-like structure when sprayed onto the desired substrate. This behavior substantially prevents the organosilicon composition from flowing downward under the force of gravity and away from the intended application area until it has had an opportunity to fully cure. In the latter respect, complete cure is not required immediately.

[0030] The polyorganosiloxane having silicon-bonded hydrogen can be linear, lightly branched, or cyclic. The polyorganosiloxane should preferably have a viscosity of less than 1,000 mPa·s so that the composition remains sprayable and thixotropic when combined with the other raw materials of the organosilicon composition. The polyorganosiloxane having silicon-bonded hydrogen may contain M siloxy units of formula (3). R 2 c H (3-c) SiO 1 / 2 (3)

[0031] In the formula, R 2 is a hydrocarbon having no ethylenic unsaturation, preferably a hydrocarbon described for R above that does not contain ethylenic unsaturation, and c is 0, 1, 2, or 3, preferably 1 or 2, and most preferably 2.

[0032] The D units present correspond to formula (4). R 2 d H (2-d) SiO 2 / 2 (4)

[0033] where d is 0, 1, or 2; R 2is synonymous with formula (3). The polyorganosiloxane containing silicon-bonded hydrogen preferably contains a substantial number of units of formula (4) where d is 0 or 1, as well as units of formula (4) where d is 2. Linear or lightly branched polyorganosiloxanes containing silicon-bonded hydrogen may contain silicon-bonded hydrogen only at the chain ends, along the polymer chain, or at both positions. The viscosity of the Si-H functional crosslinker can vary over a wide range. In particular, the crosslinker may have a higher viscosity when the silicon-bonded hydrogen content is higher, and therefore, a lower amount is present in the organosilicon composition at the same ratio of silicon-bonded hydrogen and ethylenic unsaturation. The viscosity is preferably 10,000 mPa·s or less, preferably 5,000 mPa·s or less, and most preferably 1,000 mPa·s or less. The silicon-bonded hydrogen content may range from 0.0002 to 1.7 wt.%, preferably from 0.05 to 1.2 wt.%, and more preferably from 0.1 to 1 wt.%. The silicon-bonded hydrogen-containing crosslinker should be present in a conventional amount, e.g., an amount providing 0.1 to 15 silicon-bonded hydrogen atoms per ethylenically unsaturated group, preferably 0.5 to 4 silicon-bonded hydrogen atoms per ethylenically unsaturated group. Depending on the configuration, greater or lesser amounts may also be suitable. The combination of raw materials, including the silicon-bonded hydrogen-containing crosslinker, should be such that the organosilicon composition is thixotropic and sprayable.

[0034] The addition-curable organosilicon composition contains a hydrosilylation catalyst in at least one component. Hydrosilylation catalysts are well known and are generally noble metals or their compounds or complexes. The hydrosilylation catalyst is preferably a platinum compound or complex. Examples of suitable platinum catalysts include any catalysts that have been used to date in compositions that are crosslinkable by the addition of silicon-bonded hydrogen onto aliphatic multiple bonds. Preferably, component (D) comprises a hydrosilylation catalyst from Groups 8, 9, or 10 of the periodic table. Thus, metals and their compounds, such as platinum, rhodium, palladium, ruthenium, and iridium, can be used, preferably platinum. The metal may be immobilized, if appropriate, on a finely divided support material such as activated carbon, metal oxides, alumina, or silica.

[0035] Preferred hydrosilylation catalysts (D) are platinum and platinum compounds, more preferably platinum compounds soluble in polyorganosiloxanes. Soluble platinum compounds include, for example, those of the formula (PtCl2olefin)2 and H Examples of useful soluble platinum catalysts include platinum-olefin complexes of the formula (PtCl3Olefin). The soluble platinum compounds preferably utilize alkenes having 2 to 8 carbon atoms, such as ethylene, propylene, isomers of butene, and isomers of octene, or cycloalkenes having 5 to 7 carbon atoms, such as cyclopentene, cyclohexene, and cycloheptene. Useful soluble platinum catalysts also include platinum-cyclopropane complexes of the formula (PtCl2C3H6), the reaction product of hexachloroplatinic acid with an alcohol, ether, aldehyde, or a mixture thereof, or the reaction product of hexachloroplatinic acid with methylvinylcyclotetrasiloxane in an ethanolic solution in the presence of sodium carbonate. Platinum catalysts with phosphorus, sulfur, and amine ligands are also possible, and examples include (Ph3P)2PtCl2. Particularly preferred for use as component (D) are complexes of platinum with vinyl siloxanes, such as sym-divinyltetramethyldisiloxane (Karstedt's catalyst).

[0036] The amount of platinum catalyst employed should be sufficient to crosslink the addition-curable composition. For example, amounts ranging from 0.01 ppm to 1,000 ppm, preferably 0.1 ppm to 200 ppm, and more preferably 20 ppm to 120 ppm, based on the weight of the organosilicon component, are suitable. If complete cure is desired in a short period of time, a larger amount of catalyst can be used. If slower cure is desired, a smaller amount can be used, or a larger amount can be used in combination with inhibitors known to those skilled in the art, such as ethylenically unsaturated alcohols such as dehydrolinalool, organic phosphines, organic phosphites, and other inhibitors known to those skilled in the art, such as those disclosed in paragraphs 0054 and 0055 of U.S. Patent Application Publication No. 2008 / 0006179A1, which is incorporated herein by reference. Because the platinum catalyst also functions as a ceramming catalyst in addition-curable compositions, it may be desirable to employ somewhat higher amounts of catalyst than are typically used in addition-curable silicone compositions that are not designed to cerammize at high temperatures, e.g., 50 to 400 ppm, more preferably 50 to 200 ppm, by weight of the organosilicon component. Additionally, because it is generally undesirable to heat ion battery cells, modules, or battery packs to high temperatures during manufacture, it is desirable that the amount of platinum catalyst employed promotes crosslinking at ambient temperatures or at slightly elevated temperatures of 50°C or less.

[0037] The organosilicon compound of the moisture-curable organosilicon composition of the present invention contains a silanol-terminated polyorganosiloxane, an alkoxysilane crosslinker, and, optionally, a condensation catalyst. To achieve consistent and rapid crosslinking, which may not be possible in extremely low relative humidity environments, it may be desirable to add finely divided water to the composition, for example, water in the form of an emulsion with the organopolysiloxane. Therefore, the use of a two-component composition is required, where water is contained in a component that is added just before or during spraying of the composition, or in a component that does not contain a crosslinker. Like the addition-curable composition of the present invention, the moisture-curable composition is thixotropic and sprayable, and ceramicization occurs at high temperatures due to the presence of an additional ceramicization catalyst.

[0038] The silanol-terminated polyorganosiloxane of the moisture-curable organosilicon composition is a linear, very lightly branched, or cyclic organopolysiloxane composed primarily of organosiloxy units of formula (4): R 2 e SiO (4-e) / 2

[0039] where e is 0, 1, 2, or 3, preferably 2; R 2is a hydrocarbon or substituted hydrocarbon moiety, such as those conventionally employed in the art, e.g., as disclosed above. Preferably, it is an alkyl group having 1 to 18 carbon atoms, more preferably 1 to 4 carbon atoms, more preferably a methyl group; an alkenyl or alkynyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms, although these are neither required nor preferred. When present, it is preferably a vinyl or allyl group, more preferably a vinyl group; an aryl, alkaryl, or arylalkyl group having 6 to 14 carbon atoms, preferably a phenyl or phenylethyl group, or a hydroxy or alkoxy group. The latter preferably has 1 to 4 carbon atoms, particularly a methoxy or ethoxy group. At least two hydroxy groups are present. Hydroxy and alkoxy groups are preferably present in terminal M groups where e is 3, along with one or two hydrocarbon groups as described above. Terminal silanol groups constitute the "silanol termination" requirement of silanol-terminated polyorganosiloxanes. The hydrocarbon group may be substituted with non-interfering substituents such as halogen or cyano groups, although this is not preferred. In the majority of organosiloxy units of formula (4), the units are D units, where e is 2. Preferred silanol-terminated polyorganosiloxanes are linear polydimethylsiloxanes having dimethylsilanol end groups. The silanol-terminated polyorganosiloxanes preferably contain hydrocarbon groups that are exclusively alkyl groups, preferably alkyl groups containing 1 to 4 carbon atoms, more preferably methyl or phenyl groups, and most preferably methyl groups.

[0040] The silanol-terminated polyorganosiloxane has a viscosity at 25°C of 10,000 mPa·s or less, more preferably 5,000 mPa·s or less, even more preferably 2,000 mPa·s or less, and most preferably 1,000 mPa·s or less. The amount and viscosity of the silanol-terminated polyorganosiloxane are selected so that the organosilicon composition is thixotropic and sprayable. High-viscosity silanol-terminated polyorganosiloxanes may also be used in combination with low-viscosity silanol-terminated polyorganosiloxanes, as long as the requirements for thixotropy and sprayability are met.

[0041] The moisture-curable composition contains a crosslinker. Crosslinkers for moisture-curable compositions are well known to those skilled in the art and include alkoxysilanes, acetoxysilanes, oximinosilanes, and their partial hydrolyzates. Alkoxysilanes are preferred due to their environmental tolerance of volatile hydrolysis products, particularly methanol and ethanol, compared to, for example, acetic acid in the case of acetoxysilane. Suitable crosslinkers include C 1~4 Silanes having alkoxy groups, preferably methoxy or ethoxy groups, most preferably methoxy groups. Examples include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. For example, C 1~4 Crosslinkers having alkoxy groups, preferably methoxy groups, and aminoalkyl groups, such as aminoethyl, aminopropyl, aminoethylaminopropyl, and aminopropylaminoethyl groups, are suitable, and they serve not only as crosslinkers but also as cocatalysts and adhesion promoters in moisture-curing compositions. Poly(aminoalkyl)-functional alkoxysilanes are also suitable. Examples of acetoxysilane crosslinkers include methyltriacetoxysilane, ethyltriacetoxysilane, and propyltriacetoxysilane.

[0042] A condensation catalyst is generally required. Such condensation catalysts are well known and include, for example, bismuth compounds, titanate esters, and certain tin compounds, such as tin(II) acetate, tin(II) octoate, and tin(II) laurate. Other suitable condensation catalysts can be readily identified in the patent and scientific literature. If the moisture-curable organosilicon composition is exceptionally reactive, it may be possible to avoid the presence of a condensation catalyst or limit the amount of condensation catalyst to very low concentrations. If present, the amount is generally 0.005 to 2 wt. %, preferably 0.01 to 1 wt. %, and more preferably 0.02 to 0.2 wt. %, based on the total weight of the organosilicon components.

[0043] Aqueous emulsions or water itself may be used to accelerate the cure of moisture-curable compositions. When aqueous emulsions or water are used, they are added as separate compositions or in a component that does not simultaneously contain the condensable polyorganosiloxane, crosslinker, and condensation catalyst. The aqueous emulsion or water is conveniently mixed into the remaining crosslinkable composition using a mechanical or static mixer just before spraying or during spray application, i.e., in a component located before the spray head or in a component contained as an integral part of the spray head itself. The actual location of the mixing is largely unimportant, except that mixing should not be done sufficiently before spraying to prevent the composition from prematurely curing and progressing to a viscosity that is not sprayable.

[0044] The moisture-curable composition is most preferably a two-component composition, comprising a first component containing a silanol-terminated base polymer and emulsified water, and a second component containing a crosslinker and a catalyst. The second component containing the crosslinker also typically contains a condensation catalyst and a functional or non-functional polyorganosiloxane. The latter is present to facilitate accurate metering by using the second component in larger amounts than the crosslinker alone. The second component may also contain an aminoalkyl-functional silane, such as an aminoalkylalkoxysilane. Crosslinkers and multi-component crosslinker compositions are commercially available or can be easily formulated by those skilled in the art. The amount of the second component to be mixed with the first component depends substantially on the weight percentage of the crosslinker contained in the second component. The amount of the second component can be formulated to obtain a volumetric mix ratio of the first component to the second component that can vary over a wide range, for example, from 1:2 to 20:1, preferably from 1:1 to 15:1. A suitable crosslinking agent is Wacker Catalyst T 77, which is particularly recommended in a volume ratio of 8:1 to 12:1. This crosslinking agent contains approximately 20 to 25 weight percent 1,2-bis(triethoxysilyl)ethane, 10 to 15 weight percent aminoalkylalkoxysilane, 5 to 10 weight percent carbon black, polydimethylsiloxane, and 0.3 to 1.0 weight percent tin catalyst. Because a relatively small amount of the second component is used compared to the first component, the second component may be in the form of a highly viscous or paste-like composition before mixing with the first component. Therefore, this second component may employ polyorganosiloxanes, including silanol-terminated polyorganosiloxanes with molecular weights much higher than those recommended for use in the first component. However, if the second component is used in a large proportion, such as a 1:1 or 2:1 ratio, the second component must also have a relatively low viscosity in order for the composition to remain sprayable. Compositions with a high amount of the second component have a shorter pot life and cure time, but the ultimate pot life and cure time are not solely a function of the second component, but also depend greatly on the makeup of the first component, including the amount of silanol-terminated polymer and the presence or absence of emulsified water.In the case of battery module and / or battery pack manufacturing, very fast cure rates are generally desirable to minimize assembly time per module or per battery pack.

[0045] There are several ingredients that are common to both addition-curable organosilicon compositions and one-part moisture-curable organosilicon compositions, or are optional in both of these compositions. These ingredients include ATH-containing fillers (required in both types of compositions), adhesion promoters (required in addition to the alkoxysilane crosslinker present in the moisture-curable composition, but may also be present therein to improve the organic / inorganic interface), low viscosity polyorganosiloxane diluents (optional in both components to reduce viscosity and improve sprayability), biocides (optional in both compositions, employed to combat microbial growth during storage), stabilizers (to stabilize the organosilicon component with respect to exposure to high temperatures in both types of compositions), and organic solvents (not preferred, and preferably absent, but may be used to reduce the viscosity of the system).

[0046] The ATH-containing filler is an integral part of the compositions of the present invention. The ATH-containing filler is present in both compositions in an amount of 50-85 wt. % based on the total weight of the sprayable thixotropic organosilicon composition. The ATH portion of the ATH-containing filler should be sufficient to provide at least 30 wt. % ATH based on the total weight of the organosilicon composition, preferably at least 40 wt. %, more preferably at least 50 wt. %, even more preferably at least 60 wt. %, even more preferably at least 70 wt. %, and most preferably at least 80 wt. Most preferably, the entire ATH-containing filler consists solely of ATH.

[0047] The aluminum trihydrate (ATH) is in particulate form, with an average particle size of less than 300 μm, preferably less than 200 μm, and most preferably less than 100 μm. The average particle size is preferably greater than 10 μm, more preferably greater than 20 μm. The ATH is preferably in the form of a granular material. 2 / g, more preferably less than 10m 2 / g, preferably less than 0.5m 2 / g, more preferably 0.8m 2 ATH has a BET surface area of ​​greater than 1 / g. ATH is available from numerous sources worldwide, including The RJ Marshall Company, Huber Engineered Materials, and others.

[0048] The ATH may be untreated or may be hydrophobized. The use of hydrophobized ATH has been found to be effective in reducing the viscosity so that the organosilicon composition is flowable and preferably sprayable. The ATH may be supplied in an already hydrophobized form, or may be hydrophobized in situ, for example, by including a reactive polyorganosiloxane or silane that reacts with surface hydroxyl groups after addition to the organosilicon composition. The ATH may also be hydrophobized by coating with natural or synthetic waxes, fatty acids, fatty acid salts, fatty acid esters, and other similar hydrophobic compounds known to those skilled in the art. A preferred hydrophobic ATH is HYMOD® SB36 SG, which has an aluminum hydroxide content of about 99.6% by weight, an average particle size of approximately 36 μm, and a BET surface area of ​​1.0 m 2 / g and is available from Huber Engineered Materials.

[0049] Fillers other than ATH present in the sprayable thixotropic organosilicon composition include metal carbonates, such as magnesium carbonate and calcium carbonate, magnesium hydroxide, silica, titanium dioxide, and other insoluble or sparingly soluble metal oxides. With regard to such fillers, it is important to evaluate their effect on the thermal properties of the cured organosilicon composition, as well as their effect on the viscosity and thixotropy of the organosilicon composition. It is preferable to avoid relatively expensive fillers, such as titanium dioxide. Fillers, such as carbonates, may be synthetic or natural carbonates, such as those derived from limestone, marble, or dolomite. Small amounts of some fillers, such as zinc oxide, may be added to enhance the thixotropic properties of the composition. Expanded or non-expanded mica, asbestos, talc, wollastonite, and other naturally occurring fillers are also suitable. Similarly, pyrogenic fillers, such as pyrogenic silica and pyrogenic titania, are available in very small particle sizes with correspondingly high BET surface areas. However, preferably, the BET surface area of ​​the additional filler should be the same as that of the ATH particles discussed above, especially when used in an amount greater than about 3 wt. % based on the total weight of the organosilicon composition. The additional filler may be used as prepared, i.e., non-hydrophobic, or may be provided as a hydrophobic filler by appropriate surface modification, or may be hydrophobized in situ. Inorganic fillers in the form of microballoons may also be used. Such microballoons are generally made of glass or ceramic materials and preferably have a particle size in the same range as the ATH filler. Like other non-ATH fillers, inorganic microballoons are commercially available from a number of sources. When selecting a non-ATH filler, filler density must also be considered when using an amount greater than 10 wt. % based on the total weight of the organosilicon composition.

[0050] The amount of non-ATH filler may range from 0.0% up to about 55% by weight, with 55% being a preferred upper limit, with greater than 0.0% to about 20% by weight being preferred, and greater than 0.0% to about 10% by weight being more preferred. Too much non-ATH filler can lead to reduced thermal performance.

[0051] Both addition-curable and moisture-curable organosilicon compositions contain a ceramification catalyst that promotes the conversion of the organosilicon composition to a porous ceramic material at elevated temperatures, preferably near or above 600°C, e.g., 800°C to 900°C. The composition of the ceramification catalyst can vary as long as ceramification is achieved. However, the ceramification catalyst is preferably a platinum compound, as disclosed above in paragraphs 34 and 35. In addition-curable organosilicon compositions of the present invention, the platinum hydrosilylation catalyst serves the dual function of catalyzing the curing of the organosilicon composition by hydrosilylation crosslinking. Because the platinum catalyst remains in the composition rather than being removed, the platinum hydrosilylation catalyst also functions as a ceramification catalyst. Moisture-curable compositions require the addition of a ceramification catalyst, as moisture-curable compositions do not require a platinum catalyst for crosslinking. For moisture-curable compositions, the same platinum catalysts described above may be used in the amounts described above.

[0052] Both the addition-curable and moisture-curable organosilicon compositions contain a heat stabilizer for the silicone. The heat stabilizer is present in trace amounts, e.g., 0.1% to 3% by weight, preferably 0.5% to 2% by weight, more preferably 0.5% to 1.8% by weight, and most preferably 0.5% to 1% by weight, based on the total weight of the organosilicon composition. A preferred heat stabilizer is particulate titanium dioxide, preferably provided as a dispersion in the polyorganosiloxane. The amount of titanium dioxide is not sufficient to render the composition reflective, especially when an inorganic dark pigment, such as black pigmentary iron oxide, is also present. The silicone heat stabilizer extends the upper use temperature of the silicone.

[0053] Inorganic pigments are optional components in both addition-curable and moisture-curable organosilicon compositions. Organic pigments are generally flammable and should generally be avoided. Suitable inorganic pigments are metal oxides, such as iron oxide, especially of metals other than titanium. Pigmentary iron oxides are available in a variety of colors, ranging from yellow to red to black. Black iron oxide pigments are particularly suitable. These pigments are provided in amounts of 0.1% to 5% by weight, preferably 0.5% to 4% by weight, and most preferably 0.8% to 2% by weight, based on the total weight of the organosilicon composition. These weight percentages are based on a 20% by weight dispersion of the pigment in an organopolysiloxane, preferably a vinyl-functional organopolysiloxane. A suitable pigment dispersion is SILCOPAS 220 black, available from Avient Corporation.

[0054] Both addition-curable and moisture-curable organosilicon compositions may contain an adhesion promoter. In moisture-curable compositions, an alkoxysilane crosslinker can function as an adhesion promoter. However, since alkoxysilanes are not required in addition-curable compositions, they may need to be added as an adhesion promoter in these compositions, or a separate adhesion promoter may be required in both types of compositions. These adhesion promoters preferably contain reactive and / or polar groups, such as glycidyl, acryloyl, or aminoalkyl groups. Examples include GENIOSIL GF 80 (3-glycidoxypropyltrimethoxysilane), MAPTMO silane (N-methyl-3-aminopropyltrimethoxysilane), GENIOSIL GF 91 (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane), methacryloyloxypropyltrimethoxysilane, and acetoxysilane. Partial hydrolyzates of these silane adhesion promoters may also be used. When present as a separate component, the adhesion promoter is preferably present in an amount of 0.1 to 5 wt. %, more preferably 0.2 to 4 wt. %, and even more preferably 0.2 to 3 wt. %, based on the total weight of the organosilicon composition.

[0055] The materials used for the upper and lower covers, frames, and other components of the battery module and / or battery pack are conventional. Metallic materials, such as conventional steel, stainless steel, or aluminum, are typically used to reduce flammability. Stainless steel is not preferred due to cost considerations. Aluminum is the most preferred material for reducing vehicle weight. Many metal parts in modern automobiles are painted or otherwise coated, particularly for corrosion resistance. Electrodeposition coating processes are typically used. While such coatings are extremely useful in preventing corrosion, care must be taken when using such coatings to evaluate their effect on the thermal properties of the battery module and / or battery pack. For example, but not by way of limitation, certain electrocoatings have been found to significantly reduce the heat resistance provided by the organosilicon composition of the present invention. Therefore, it is important to use the actual materials used in manufacturing when testing thermal conductivity. In particular, non-electrodeposited aluminum covers have been found to be particularly suitable for extending the time before the exposed surface of the cover reaches unacceptable temperatures. Electrodeposition coating of the top and bottom (exterior) surfaces of the top and bottom covers is generally not a problem.

[0056] Organosilicon compositions are sprayable because they are relatively low-viscosity fluids under moderate shear. These properties also enable coating methods typical of flowable compositions, such as doctor blade coating and spin coating. However, many of the components of battery modules and / or battery packs are non-planar and therefore not suitable for these application methods, making it highly desirable for the compositions to be sprayable. To be sprayable, the viscosity must be relatively low under the shear experienced by the spray nozzle. In this regard, while directional spraying, such as by impinging the organosilicon composition on a rotating disk, is possible, it is preferable to utilize conventional spraying equipment. Such equipment can easily spray compositions having viscosities of up to about 30,000 mPa·s or higher. At viscosities above about 20,000 mPa·s, spraying becomes difficult, although possible. Given the high filler content of the organosilicon compositions of the present invention, it is quite surprising that the compositions are sprayable. The viscosity of the organosilicon compositions at low levels of shear is quite high, e.g., within 0.5 seconds. -1 The viscosity is 35,000 mPa·s or more at rest, and even higher. However, the composition is thixotropic, i.e., shear-thinning, and therefore can be effectively sprayed. To further improve sprayability or to allow spraying of more viscous compositions, the spraying device may be equipped with an ultrasonic transducer to reduce the local viscosity near the spray head. Both high-pressure and low-pressure sprayers may be used, with or without air or other gas flow. The thickness of the applied coating before curing is preferably 0.2 to 5 mm, more preferably 0.5 to 2.5 mm. The thickness of the cured coating is substantially the same as the thickness before curing. Preferably, the coating is cured within 200 seconds. -1 The viscosity at 1000 kJ / min is less than 10,000 mPa·s, more preferably less than 7,000 mPa·s, even more preferably less than 5,000 mPa·s, and most preferably less than 4,000 mPa·s.

[0057] Preferably, the organosilicon composition is sprayed onto the underside of the top cover (preferably an aluminum sheet material) of the battery module and / or battery pack. The sprayed organosilicon composition begins to harden immediately and can be fully or completely cured before assembling the cover to the remaining battery components, or the cover and applied organosilicon composition may be placed on the remaining components while still in a very low cured state. If the surface of the curable organosilicon composition is still tacky, applying the cover to the remaining components before full curing may improve the mechanical strength of the battery module and / or battery pack. [Example]

[0058] The present invention will now be illustrated by the following non-limiting examples. The viscosity of the composition is measured at room temperature or 25°C and can be evaluated, for example, as disclosed in ISO 3219. Based on the examples below and the discussion above, one skilled in the art can prepare a wide variety of compositions that are flowable, preferably sprayable, and thixotropic, contain the required amount of ATH-containing filler, and are suitable for producing thermal insulators for metal-ion batteries. All parts referred to herein are parts by weight. All percentages referred to herein are % by weight.

[0059] [Example 1] The addition-curable organosilicon composition is prepared as a two-component composition.

[0060] The first component was prepared from 4 parts by weight of GENIOSIL® GF 80; 1 part by weight of MAPTMO silane; 24 parts by weight of VIPO 120 (a vinyl-functional polymer having a viscosity of 120 mPa·s available from Wacker Chemie AG); 5.2 parts by weight of SILCOPAS 220 Fe3O4 (an iron oxide dispersion in a vinyl-functional polyorganosiloxane); 0.8 parts by weight of POLYMER VI-P-5 (an oligomeric vinyl-functional polyorganosiloxane having an average of about 3 vinyl groups per molecule available from Wacker Chemie AG); 0.8 parts by weight of CATALYST EP (a platinum catalyst for vinyl-functional polydimethylsiloxanes available from Wacker Chemie AG); and 130 parts by weight of Huber SB-36 SG. ATH; 4 parts by weight of a silicone heat stabilizer (containing approximately 34% by weight of titanium dioxide dispersed in 40% by weight of a vinyl-functional organopolysiloxane having a viscosity of approximately 1,100 mPa·s, and also containing small amounts of platinum catalyst solution and GENIOSIL® GF 91); 3 parts by weight of hexadecyltrimethoxysilane; and 10 parts by weight of a silanol-terminated polydimethylsiloxane (viscosity approximately 1,000 mPa·s).

[0061] The second component is prepared by mixing 8 parts by weight of a Si-H functional polydimethylsiloxane crosslinker (containing 0.77% by weight of silicon-bonded hydrogen); 3 parts by weight of GENIOSIL GF 80; 1 part by weight of MAPTMO silane; 9.8 parts by weight of a Si-H functional polydimethylsiloxane crosslinker (containing approximately 0.15% by weight of silicon-bonded hydrogen); 12 parts by weight of VIPO 120 (a vinyl-functional polyorganosiloxane having a viscosity of approximately 120 mPa·s); 130 parts by weight of Huber SB-36 SG ATH; 3 parts by weight of hexadecyltrimethoxysilane; 10 parts by weight of a silanol-terminated polydimethylsiloxane (viscosity approximately 1,000 mPa·s); and 4 parts by weight of the silicone heat stabilizer employed in the first component.

[0062] The two components were fed separately into a static mixer positioned immediately before the spray head and sprayed onto a 0.6 mm aluminum substrate at a thickness of approximately 4 mm. The coated sheet was held vertically in place with a welding clamp, and a propane burner with a flame temperature of 850-1000°C was placed 2.5 cm from the silicone surface. The temperature of the opposite side of the sheet was measured using a FLIR autofocus thermal imaging camera, which is useful for measuring temperatures between 0 and 650°C (with an accuracy of approximately ±2°C). The exterior of the panel did not reach 350°C after 8 minutes, whereas a similar panel made from electrocoated steel without the organosilicon composition reached this temperature in less than 10 seconds. Examination of the organosilicon coating after this exposure to temperatures exceeding 600°C reveals the presence of a black, porous ceramic material. This organosilicon composition provides surprisingly effective thermal insulation at the high temperatures to which it is exposed.

[0063] [Example 2] A moisture-curable first component is prepared by mixing 6.3 parts by weight of the silicone heat stabilizer used in Example 1, 255.5 parts by weight of ATH, 0.85 parts by weight of emulsion (an emulsion of approximately 35% by weight of water dispersed in silicone), and 115.6 parts by weight of silanol-terminated polydimethylsiloxane (viscosity approximately 1,000 mPa·s). The second component is Wacker Catalyst T 77, available from Wacker Chemie AG, and is used in a first component to second component ratio of 10:1. The mixed components are sprayable and sprayed onto panels in a manner similar to Example 1. When subjected to the same fire test as used in Example 1, the opposing surfaces of the panels do not reach 350°C for more than 8 minutes.

[0064] The room temperature viscosity for the first component (without catalyst) was measured at a shear rate of 0.5 s -1 38,000 mPa·s for 5 seconds -1 15,000 mPa·s for 10 seconds -1 13,700 mPa·s, and 192 seconds -1 The second component is 4,490 mPa·s at 0.5 seconds. -1The viscosity of the mixed first and second components measured immediately after mixing was approximately 200,000 mPa·s at a shear rate of 0.5 s -1 43,600 mPa·s for 5 seconds -1 15,500 mPa·s for 10 seconds -1 13,800 mPa·s, and 192 seconds -1 The viscosity is very high at low shear rates, reaching 6,160 mPa·s at a shear rate of 192 s -1 Note that this reduces it to about one-sixth.

Claims

1. (a) an array of a plurality of individual metal-ion batteries; (b) optionally, a frame laterally surrounding the array of the plurality of individual metal ion batteries; (c) optionally, a bottom cover; (d) a top cover; and (e) a crosslinked curable silicone composition disposed between the array of cells and at least one of the bottom cover and / or top cover; An electric vehicle battery assembly comprising: the curable silicone composition is a sprayable, thixotropic, addition-curable or moisture-curable silicone composition comprising, based on the total weight of the curable silicone composition, greater than 50 wt. % and less than 85 wt. % of an aluminum trihydrate-containing filler and at least one ceramming additive that promotes ceramming of the crosslinked silicone composition upon exposure to a temperature of 600°C or greater, the aluminum trihydrate-containing filler comprising at least 30 wt. % aluminum trihydrate particles; the crosslinked silicone composition reduces heat conduction from a surface of the crosslinked silicone composition closest to the array of the plurality of battery cells through the crosslinked silicone composition to an outer surface of the lower cover or the upper cover, so that when the surface of the crosslinked silicone composition closest to the array of the plurality of battery cells is exposed to a heat source having a temperature of greater than 850°C located 2.5 cm from the surface, the outer surface does not reach a temperature of 350°C for at least 2 minutes; Battery assemblies for electric vehicles.

2. 10. The electric vehicle battery assembly of claim 1, wherein the array of a plurality of individual cells is in the form of a battery module, each module comprising a second plurality of individual cells, and wherein the organosilicon composition is applied to a top cover of the battery assembly.

3. the sprayable thixotropic silicone composition is an at least two-component addition-curable silicone composition; (a) the first component is (i) 20 to 70 wt. %, based on the total weight of all organosilicon compounds, of at least one vinyl-functional polyorganosiloxane having a viscosity of less than 4,000 mPa·s, preferably less than 1,000 mPa·s; (ii) optionally, 20 to 40 wt. %, based on the total weight of all organosilicon compounds, of one or more silanol-terminated polyorganosiloxanes or non-functional polyorganosilanes having a viscosity of less than 10,000 mPa·s, preferably less than 1,000 mPa·s; (iii) at least one silane adhesion promoter; (iv) at least one hydrosilylation catalyst; (v) optionally, a filler; Including, (b) the second component is (i) at least one Si—H functional crosslinker; (ii) optionally, one or more silanol-terminated organopolysiloxanes or non-functional polyorganosiloxanes having a viscosity of less than 10,000 mPa·s, preferably less than 1,000 mPa·s; (iii) optionally, one or more silane adhesion promoters; (iv) optionally, a filler; Including, at least one of the first and second components contains a filler comprising aluminum trihydrate and a silicone heat stabilizer, the total amount of filler present in all components is 50% to 85% by weight, and the aluminum trihydrate is present in the filler(s) in an amount sufficient to provide at least 30% by weight aluminum trihydrate, preferably at least 50% by weight aluminum trihydrate, more preferably at least 70% by weight aluminum trihydrate, and most preferably at least 80% by weight aluminum trihydrate, based on the total weight of all components, and at least one component contains the ceramifying additive, preferably a platinum-containing ceramifying additive, and at least one of the components contains a silane adhesion promoter; 10. The electric vehicle battery assembly of claim 1.

4. 4. The electric vehicle battery assembly of claim 1, further comprising up to 5 wt. % of a heat stabilizer composition comprising titanium dioxide.

5. the sprayable thixotropic silicone composition is a moisture-curable silicone composition; (i) at least one silanol-terminated polyorganosiloxane having a viscosity less than 10,000 mPa·s in an amount greater than 90 wt %, based on the total weight of the organosilicon component; (ii) at least one ceramming additive that promotes ceramming of said organosilicon composition; (iii) optionally, a 0.01 to 2% by weight emulsion of water and silicone; (iv) at least one alkoxysilane crosslinker; (v) optionally an adhesion promoter different from component (iv), and (iv) 50 to 85 wt. % of an aluminum trihydrate-containing filler, in an amount sufficient to provide at least 30 wt. % of aluminum trihydrate based on the total weight of the silicone composition; and (v) at least one heat stabilizer; 3. The electric vehicle battery assembly of claim 1 or 2, comprising:

6. 6. The electric vehicle battery assembly of claim 5, wherein the moisture-curable silicone composition is a composition of at least two components, one component comprising a water and silicone emulsion and a silanol-terminated organopolysiloxane, and a second component comprising an alkoxysilane crosslinker.

7. 6. The electric vehicle battery assembly of claim 5, wherein the silicone heat stabilizer comprises titanium dioxide in an amount sufficient to provide a titanium dioxide content of 0.1 to 3 wt. % based on the total weight of the silicone composition, preferably 0.2 to less than 2 wt. %.

8. 10. A high temperature crosslinkable organosilicon composition useful in the manufacture of a metal ion automotive battery assembly according to claim 1, comprising: an addition-curable or moisture-curable silicone composition containing more than 50 wt.% and less than 85 wt.% of an aluminum trihydrate-containing filler, based on the total weight of the curable silicone composition, and sufficient to provide at least 30 wt.% aluminum trihydrate, preferably at least 50 wt.% aluminum trihydrate, more preferably at least 70 wt.% aluminum trihydrate, and most preferably at least 80 wt.% aluminum trihydrate, based on the total weight of the organosilicon composition; a silicone heat stabilizer; and at least one ceramifying additive that promotes ceramifying the organosilicon composition. Including, A heat-resistant crosslinkable organosilicon composition, wherein the curable silicone composition, after crosslinking to form a crosslinked silicone, reduces heat conduction from a side of a metal substrate coated with the crosslinked silicone composition to an opposing side of the metal substrate, such that when the side of the crosslinked silicone composition opposing the metal substrate is exposed to a heat source that raises the temperature of the surface of the crosslinked silicone to 600°C or higher, the opposing side of the metal substrate does not reach a temperature of 350°C or higher for at least 2 minutes.

9. (a) a first component comprising: (i) at least one vinyl-functional polyorganosiloxane having a viscosity of less than 4000 mPa·s, preferably less than 1000 mPa·s, in an amount of 20 to 70 wt. %, based on the total weight of all organosilicon components; (ii) optionally, at least one silanol-terminated or non-functional polyorganosiloxane having a viscosity of less than 10,000 mPa·s, preferably less than 1,000 mPa·s, in an amount of less than 30% by weight, based on the total weight of all organosilicon compounds; (iii) optionally, a silane adhesion promoter; (iv) at least one hydrosilylation catalyst; (v) optionally, a filler, and (b) a second component comprising: (i) at least one Si—H crosslinker; (ii) optionally, one or more silanol-terminated organopolysiloxanes or non-functional organopolysilanes having a viscosity of less than 10,000 mPa·s, preferably less than 1,000 mPa·s, in an amount of less than 30% by weight, based on the total weight of all organosilicon compounds; (iii) optionally, one or more silane adhesion promoters; (iv) optionally, a filler; 1. A sprayable, thixotropic, multi-component, addition-curable silicone composition comprising at least two components:

9. The heat resistant crosslinkable organosilicon composition of claim 8, wherein at least one component contains an aluminum trihydrate-containing filler, the total amount of aluminum trihydrate-containing filler present in all components being 50% to 85% by weight and sufficient to provide at least 30% by weight aluminum trihydrate, preferably at least 50% by weight aluminum trihydrate, more preferably at least 70% by weight aluminum trihydrate, and most preferably at least 80% by weight aluminum trihydrate, based on the total weight of the curable silicone composition; at least one component contains a ceramming additive that promotes ceramming of the organosilicon at temperatures of 600°C or greater; at least one component contains a silicone heat stabilizer comprising titanium dioxide; and at least one component contains a silane adhesion promoter.

10. 10. A sprayable, thixotropic, moisture-curable organosilicon composition suitable for producing the metal ion automotive battery assembly of claim 1, comprising: (i) at least one silanol-terminated polyorganosiloxane having a viscosity of less than 10,000 mPa·s, preferably less than 1,000 mPa·s, in an amount greater than 90 wt%, based on the total weight of the organosilicon components of the organosilicon composition; (ii) a silicone heat stabilizer, and (iii) at least one ceramifying additive that promotes ceramifying of said organosilicon composition at temperatures above 600°C; (iv) optionally, 0.01 to 2% by weight of an emulsion of silicone and water; and (v) 50 to 85 wt. % of an aluminum trihydrate-containing filler, based on the total weight of the organosilicon composition, containing aluminum trihydrate in an amount sufficient to provide at least 30 wt. % aluminum trihydrate, preferably at least 50 wt. % aluminum trihydrate, more preferably at least 70 wt. % aluminum trihydrate, and most preferably at least 80 wt. % aluminum trihydrate, based on the total weight of the organosilicon composition; Including, A sprayable, thixotropic, moisture-curable organosilicon composition that, after curing to form a crosslinked silicone composition, reduces heat conduction from a side of a metal substrate coated with the crosslinked silicone composition to an opposing side of the metal substrate, such that when the side of the crosslinked silicone composition facing the metal substrate is exposed to a heat source having a temperature of 850°C at a position 2.5 cm from the surface of the crosslinked silicone, the opposing side of the metal substrate does not reach a temperature of 350°C or higher for at least 2 minutes, preferably at least 5 minutes, and more preferably at least 8 minutes.

11. 11. The moisture-curable organosilicon composition of claim 10, wherein the moisture-curable silicone composition is a composition of at least two components, one component comprising an emulsion of water in silicone and a silanol-terminated organopolysiloxane, and the other component comprising an alkoxysilane crosslinker and a condensation catalyst.

12. 11. An organosilicon composition according to claim 9 or 10, wherein the silicone heat stabilizer comprises titanium dioxide in an amount sufficient to provide from 0.1 to 3 wt. % titanium dioxide, preferably from 0.2 to less than 2 wt. % titanium dioxide, based on the total weight of the organosilicon composition.

13. 3. A method for manufacturing the metal ion battery module and / or battery pack according to claim 1 or 2, comprising: (a) assembling a plurality of individual metal ion battery cells into a battery module, and optionally assembling a plurality of said battery modules into a battery pack; (b) providing at least a top metal cover dimensioned to enclose at least a top surface of said battery module and / or battery pack, and optionally a bottom metal cover dimensioned to enclose at least a bottom surface of said battery module and / or battery pack; (c) applying to at least the top metal cover a flowable, preferably sprayable, thixotropic, crosslinkable organosilicon composition comprising the addition-curable or moisture-curable organosilicon component and an aluminum trihydrate-containing filler in an amount of 50 to 85 weight percent, based on the total weight of the organosilicon composition; (d) placing a top metal cover over the plurality of metal ion battery cells or battery modules; Equipped with the amount of aluminum trihydrate-containing filler and the proportion of aluminum trihydrate in the aluminum trihydrate-containing filler are such as to provide at least 30 wt.% aluminum trihydrate, more preferably at least 50 wt.% aluminum trihydrate, even more preferably at least 70 wt.% aluminum trihydrate, and most preferably at least 80 wt.% aluminum trihydrate, based on the weight of the organosilicon composition; and further comprising a silicone heat stabilizer and at least one ceramifying additive; The crosslinkable organosilicon composition, after crosslinking to form a crosslinked silicone, reduces heat conduction from a side of the metal substrate coated with the crosslinked silicone composition to an opposing side of the metal substrate, such that when the side of the crosslinked silicone composition opposing the metal substrate is exposed to a heat source that raises the temperature of the crosslinked silicone to 600°C or higher, the opposing side of the metal substrate does not reach a temperature of 350°C or higher for at least 2 minutes.

14. An ion battery module or battery pack manufactured by the method of claim 13.

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