Thermal control sheet, manufacturing method, and articles using the same

Abstract

A method for forming a thermal management sheet for a battery comprising a cured polyurethane foam, comprising the steps of: combining an active hydrogen-containing component comprising a polyol and an isocyanate component comprising a polyisocyanate to form an uncured polyurethane foam; and curing the uncured polyurethane foam to form a cured polyurethane foam, wherein the uncured polyurethane foam comprises 3 to 68 mass percent of sodium borate, 0.1 to 7 mass percent of a surfactant, and 0.001 to 9 mass percent of a catalyst, relative to the total mass of the uncured polyurethane foam, the cured polyurethane foam having a density of 12 to 35 pounds / cubic foot, and the cured polyurethane foam having a thickness of 1 to 30 millimeters.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 463,639, filed on 3 May 2023. This related application is incorporated herein by reference in its entirety. [Background technology]

[0002] This application relates to a thermal management sheet for use in batteries, particularly for delaying or preventing thermal runaway in lithium-ion batteries. This application further relates to the thermal management sheet and battery components and a method for manufacturing a battery including the thermal management sheet.

[0003] Demand for electrochemical energy storage devices such as lithium-ion batteries is increasing due to the growth of applications such as electric vehicles and grid energy storage systems, as well as other multi-cell battery applications, such as electric bicycles, uninterruptible power supply battery systems, and lead-acid battery replacements. With their increased use, methods for thermal management are desired. In large-scale applications such as grid storage and electric vehicles, multiple electrochemical cells are often used in series and parallel arrays, which can lead to thermal runaway. When a cell enters thermal runaway mode, the heat generated by the cell can induce thermal runaway propagation reactions in adjacent cells, potentially causing a cascade effect and igniting the entire battery.

[0004] Attempts to reduce thermal runaway in batteries have been explored, but many have drawbacks. For example, modifying the electrolyte by adding flame retardant additives or using an inherently non-flammable electrolyte have been considered, but these methods can negatively impact the electrochemical performance of the battery. Other methods for thermal management or preventing thermal runaway cascades include increasing the amount of insulation incorporated between cells or clusters of cells to reduce the amount of heat transfer during thermal events. However, these methods may limit the upper limit of the energy density that can be achieved. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] With the increasing demand for batteries with improved thermal management or reduced risk of thermal runaway, there is a need for methods to prevent or delay the spread of heat, energy, or both to surrounding cells, and for components to be used in batteries. [Means for solving the problem]

[0006] In one embodiment, a method for forming a thermal management sheet for a battery comprising cured polyurethane foam comprises the steps of: combining an active hydrogen-containing component comprising a polyol and an isocyanate component comprising a polyisocyanate to form an uncured polyurethane foam; and curing the uncured polyurethane foam to form a cured polyurethane foam, wherein the uncured polyurethane foam comprises 3 to 68 wt% or 14 to 36 wt% sodium borate, 0.1 to 7 wt% or 2 to 5 wt% surfactant, and 0.001 to 9 wt%, or 0.04 to 9 wt%, or 0.04 to 7 wt%, or 3 to 7 wt% catalyst, relative to the total mass of the uncured polyurethane foam, and the cured polyurethane foam comprises 12 to 35 pounds / cubic foot (pcf) (192 to 561 kilograms / cubic meter (kg / m²)). 3 )) or 15-20 pcf (240-320 kg / m³) 3The cured polyurethane foam has a density of 1-30 mm, or 1-20 mm, or 1-15 mm, or 1-10 mm, or 1-8 mm, or 1.5-8 mm, or 1.5-6 mm, or 2-4 mm in thickness.

[0007] The battery assembly includes the thermal management sheet described above, which is placed on the surface of the electrochemical cell.

[0008] A battery including the above assembly is also disclosed.

[0009] The above and other features are illustrated by the following drawings, detailed description, examples, and claims.

[0010] The following is a brief description of the drawings, which are presented for illustrative purposes only and not to limit the exemplary embodiments disclosed herein. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of a thermal management sheet in one embodiment. [Figure 2] This is a schematic diagram of one embodiment of a thermal management sheet placed between two cells. [Figure 3] This is a schematic diagram of one embodiment of a thermal control sheet placed between two electrochemical cells. [Figure 4] This is a schematic diagram of one embodiment of a thermal management sheet placed in a cell array. [Figure 5] This is a schematic diagram of one embodiment of a battery assembly including a thermal management sheet. [Figure 6] This is a schematic diagram of the apparatus for hot plate testing. [Figure 7] This graph shows the results of the hot plate tests for Comparative Examples 1 and 2, comparing temperature (°C) with time (minutes (min)). [Figure 8]It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Examples 1 and 2, and Comparative Examples 3 to 6. [Figure 9] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Examples 3 to 7. [Figure 10] It is a graph of hot plate temperature (°C) at the 10 - minute point vs. parts of sodium borate showing the results of the hot plate tests for Examples 3 to 7. [Figure 11] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Comparative Examples 7 and 13 to 15. [Figure 12] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Comparative Examples 8 to 13. [Figure 13] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Comparative Examples 16 and 17. [Figure 14] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Comparative Examples 18 to 21. [Figure 15] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Examples 13 and 14, and Comparative Examples 22 to 26. [Figure 16] It is a graph of temperature (°C) vs. time (min) showing the results of the hot plate tests for Examples 15 to 19. [Figure 17] It is a graph of temperature (°C) at the 10 - minute point vs. thickness (inch (in)) showing the results of the hot plate tests for Examples 11a to 11i. [Figure 18] It is a graph of temperature (°C) at the 10 - minute point vs. density (pcf) showing the results of the hot plate tests for Examples 11a to 11i. [Figure 19] It is a graph of temperature (°C) at the 10 - minute point vs. density (pcf) showing the results of the hot plate tests for Comparative Example 1a, and Examples 9a, 10a, 10b, 10c, 11a, 11e and 11h. [Figure 20]This graph shows the results of the hot plate test for Examples 9a, 10b, and 11a, comparing the temperature (°C) at 10 minutes with the sodium borate portion. [Figure 21] This graph shows the results of the hot plate test for Comparative Example 1a, and Examples 9a, 10a-10c, and 11a-11i, comparing temperature (°C) with the mass of sodium borate per square millimeter (mm²) at 10 min. [Figure 22A] This is a schematic exploded view of the apparatus for the nail penetration test. [Figure 22B] Figure 22A is a schematic, non-exploded view. [Figure 23] This graph shows the results of the nail-piercing test for Examples 9a, 10b, and 11a, comparing the nail-piercing delay (seconds) to the sodium borate portion. [Figure 24] This graph shows the results of the nail penetration test for Examples 11a to 11i, comparing nail penetration delay (seconds (s)) with thickness (in). [Figure 25] This graph shows the results of the nail penetration test for Examples 11a to 11i, with respect to nail penetration delay (seconds (s)) versus density (pcf). [Modes for carrying out the invention]

[0012] Thermal management in batteries, particularly in batteries containing multiple large electrochemical cells, is a challenging problem because adjacent cells to a cell experiencing thermal runaway may absorb enough energy from the event to rise above their designed operating temperature, potentially leading to thermal runaway in those adjacent cells as well. This propagation of the onset of a thermal runaway event can trigger a chain reaction, causing one cell to ignite an adjacent cell, leading to a cascade of thermal runaways. Achieving effective thermal management characteristics in very thin sheets, such as those with a total thickness of 1-30 mm, or 1-20 mm, or 1-15 mm, or 1-10 mm, or 1-8 mm, or 1.5-8 mm, or 1.5-6 mm, or 2-4 mm, is especially difficult. Thin sheets are increasingly desirable to reduce the size and mass of articles and conserve material.

[0013] The inventors have found that a thermal control sheet containing cured polyurethane foam and sodium borate in disclosed amounts (e.g., 3-68 wt% or 14-36 wt% sodium borate relative to the total mass of the uncured polyurethane foam) can prevent or reduce the intensity of such thermal runaway events. The inventors have further found that certain components in disclosed amounts form a cured polyurethane foam containing sodium borate that is effective as a thermal control sheet. For example, 12-35 pcf (192-561 kg / m²). 3 ) or 15-20 pcf (240-320 kg / m³) 3A cured polyurethane foam containing sodium borate having a density of ) can provide effective thermal control, and a disclosed amount of surfactant (e.g., 0.1-7 wt% or 2-5 wt% of surfactant relative to the total mass of the uncured polyurethane foam) brings about appropriate foaming to provide the desired density. Furthermore, a disclosed amount of catalyst (e.g., 0.001-9 wt%, or 0.04-9 wt%, or 0.04-7 wt%, or 3-7 wt% of catalyst relative to the total mass of the uncured polyurethane foam) cures the uncured polyurethane foam containing sodium borate to provide an effective thermal control sheet. An appropriate combination of factors such as sheet thickness, amount of sodium borate, and foam density can lead to effective thermal control.

[0014] A method for forming a battery thermal management sheet containing cured polyurethane foam includes the steps of: combining an active hydrogen-containing component containing a polyol (also referred to herein as "Part A") and an isocyanate component containing a polyisocyanate (also referred to herein as "Part B") to form an uncured polyurethane foam; and curing the uncured polyurethane foam to form a cured polyurethane foam. In one embodiment, the thermal management sheet is essentially made of cured polyurethane foam or consists of cured polyurethane foam.

[0015] In one embodiment, an uncured polyurethane foam composition is provided, comprising a polyol; polyisocyanate; 3-68 wt% or 14-36 wt% sodium borate; 0.1-7 wt% or 2-5 wt% surfactant; and 0.001-9 wt%, or 0.04-9 wt%, or 0.04-7 wt%, or 3-7 wt% catalyst, wherein the mass percentage is relative to the total mass of the uncured polyurethane foam composition. In one embodiment, the uncured polyurethane foam composition comprises a polyol; polyisocyanate; 14-36 wt% sodium borate; 2-5 wt% surfactant; and 3-7 wt% catalyst, with the mass percentage being relative to the total mass of the uncured polyurethane foam composition.

[0016] The use of sodium borate has unexpectedly been found to be particularly useful in the manufacture of thermal management sheets containing polyurethane foam. Thermal management sheets can be very thin and have good thermal insulation properties. Thermal management sheets can have further advantageous properties, such as good puncture resistance. Thermal management sheets can be subjected to multiple heating and cooling cycles and still provide good thermal insulation. Thermal management sheets can provide further pressure management to electrochemical cells and batteries. Thermal management sheets can be used at various locations in batteries to prevent thermal runaway. Thermal management sheets can further improve the flame retardancy of batteries.

[0017] The thermal control sheet comprises a flexible porous layer and sodium borate. One embodiment is shown in Figure 1, in which the thermal control sheet 10 comprises a flexible polyurethane foam layer 12, for example, cured polyurethane foam, having a first outer surface 14 and a second outer surface 16 on the opposite side. Although shown as flat, one, both, or all of the outer surfaces may be curved to better match the surface of the electrochemical cell.

[0018] The flexible polyurethane foam layer 12 further includes a plurality of openings, i.e., pores. The pores are defined by the inner surface of the flexible foam material. The pores may be interconnected or individual. Combinations of interconnected and individual pores may exist. The pores may be entirely contained within the sheet, or at least some of the pores may be open to the surface of the sheet, allowing communication with the surrounding environment. In one embodiment, at least some of the pores are interconnected and at least some of the pores are open, allowing the passage of air, water, water vapor, etc. from the first outer surface 14 to the opposite second outer surface 16, and is referred to herein as “open-cell foam”. In one embodiment, the foam may be “closed-cell foam”, where the pores may or may not be interconnected, are substantially not open to the surface of the sheet or are completely closed, and as a result, the sheet is substantially inaccessible to air, water, water vapor, etc. from one outer surface to the other. In one embodiment, the foam is substantially closed-cell foam or completely closed-cell foam.

[0019] Referring further to Figure 1, sodium borate 22 is distributed within the flexible polyurethane foam layer 12. The sodium borate may be distributed essentially uniformly, or as a gradient increasing, for example, from the first outer surface 14 to the second outer surface 16. As used herein, the phrase “placed within ~” may mean that the sodium borate is distributed within the matrix of the polyurethane foam layer, as shown in Figure 1. Furthermore, as used herein, the phrase “placed within ~” may mean that the sodium borate is, for example, placed within the pores of the polyurethane foam layer by coating the inner surfaces of the flexible foam material, or may be placed within the pores. Some of the pores in the polyurethane foam layer may contain sodium borate, or substantially all or all of the pores may contain sodium borate. Each pore containing sodium borate may independently be partially filled, essentially completely filled, or completely filled.

[0020] The polyurethane foam is selected to be inert to the normal operating conditions of batteries such as lithium-ion batteries, as described in detail herein, and to act as a carrier for sodium borate. Various polyurethane foams can be used.

[0021] While we do not wish to be bound by any theory, it should be understood that when exposed to heat, sodium borate can produce or generate water, and that water can mitigate heat transfer to adjacent cells. As used herein, “produce water” may refer, for example, the release of water from a hydrate, or, for example, the formation of water by a chemical reaction process. Furthermore, the water produced may be in the form of liquid or water vapor. As used herein, therefore “water” includes liquid water, water vapor, or a combination thereof. As used herein, “heat” means heat above the normal operating temperature of the battery, and includes heat produced by a flame or contact with a flame. Such temperatures may be 100°C or above, or 200°C or above, or 300°C or above, or 500°C or above. Without being bound by theory, it is considered that by producing water from sodium borate, heat shielding properties may be provided by heat absorption, heat redistribution, or water evaporation.

[0022] Sodium borate can be incorporated into polyurethane foam during its manufacture. As described herein, sodium borate may be located within the polyurethane matrix of the polyurethane foam layer, within the pores of the polyurethane foam layer, or both. Some of the pores in the polyurethane foam layer may contain sodium borate, or substantially all or all of the pores may contain sodium borate. Each pore containing sodium borate may independently be partially filled, essentially completely filled, or completely filled. In one embodiment, where the sodium borate particles are large relative to the diameter of the pore, or where the pore is essentially or completely filled with a plurality of smaller particles of sodium borate, the movement of sodium borate within the pore may be restricted. Sodium borate can be placed in the pores during the manufacture of the layer (for example, by including sodium borate in the composition used to form the polyurethane foam layer), or sodium borate can be impregnated into the pores after the manufacture of the polyurethane foam layer using a suitable liquid carrier, vacuum, or other suitable method.

[0023] Various combinations of arrangements can be used. For example, sodium borate in the pores of a polyurethane foam layer can be used in combination with sodium borate distributed within the polyurethane foam layer.

[0024] In one embodiment, to smooth the surface of the layer, almost, substantially all, or all of the sodium borate particles have a maximum dimension less than the thickness of the layer or pores in which they are located. Therefore, the specific diameter used depends on the arrangement of the sodium borate particles. Bimodal, trimodal, or more multimodal distributions of sodium borate particles can be used. For example, a bimodal distribution of sodium borate particles may exist when sodium borate is present in the matrix of the polyurethane foam layer and in the pores of the polyurethane foam layer.

[0025] Sodium borate contained in polyurethane foam can generate water when exposed to a heat source. This water can cause the polyurethane foam to expand, creating counterpressure. Without being bound by theory, generating water can absorb heat and prevent thermal runaway. Furthermore, heat can be absorbed by converting liquid water into water vapor. The heat capacity of sodium borate can further contribute to heat absorption.

[0026] Other fillers, such as aluminum trihydroxyoxide (ATH) and zinc borate, either alone or in combination with each other, or either alone or in combination with sodium borate, may not work as well in polyurethane foam as sodium borate alone. In one embodiment, the uncured polyurethane foam contains 0 wt% aluminum hydroxide based on the total mass of the uncured polyurethane foam. In one embodiment, the uncured polyurethane foam contains 0 wt% zinc borate based on the total mass of the uncured polyurethane foam. In one embodiment, the uncured polyurethane foam contains 0 wt% aluminum hydroxide and 0 wt% zinc borate based on the total mass of the uncured polyurethane foam.

[0027] ATH and zinc borate, either alone or in combination with each other, may be included in combination with sodium borate to produce the desired results. In one embodiment, the uncured polyurethane foam may further contain 0 to 33 wt%, or greater than 0 to 33 wt%, or 7 to 18 wt% of aluminum hydroxide, based on the total mass of the uncured polyurethane foam. In one embodiment, the uncured polyurethane foam may further contain 0 to 33 wt%, or greater than 0 to 33 wt%, or 7 to 18 wt% of zinc borate, based on the total mass of the uncured polyurethane foam. In one embodiment, the uncured polyurethane foam may further contain 0 to 33 wt%, or greater than 0 to 33 wt%, or 6 to 18 wt% of aluminum hydroxide and 0 to 33 wt%, or greater than 0 to 33 wt%, or 6 to 18 wt% of zinc borate, based on the total mass of the uncured polyurethane foam.

[0028] Sodium borate is available from manufacturers such as SAE Manufacturing Specialties Corp., Surepure Chemetals, Inc., Mil-Spec Industries, Noah Chemicals, ProChem, Inc., Rose Mill Co., US Borax, Quality Borate, and BariteWorld. Zinc borate is available from manufacturers such as SAE Manufacturing Specialties Corp., Surepure Chemetals, Inc., Mil-Spec Industries, Noah Chemicals, ProChem, Inc., Rose Mill Co., US Borax, Quality Borate, and BariteWorld. ATH is available from manufacturers such as SAE Manufacturing Specialties Corp., Surepure Chemetals, Inc., Mil-Spec Industries, USALCO, LLC, Cimbar Performance Metals, Huber Engineered Materials, LKAB Minerals, MarkeTech International, RJ Marshall Company, Aluchem, and Alcan Chemicals.

[0029] Thermal control sheets can be manufactured from polyurethane foam-forming compositions. Sodium borate can be incorporated into the polyurethane foam-forming composition before the polyurethane foams up and hardens.

[0030] Polyurethane foam can be formed from a reactive composition comprising an active hydrogen-containing composition, a reactive organic isocyanate-containing component, a surfactant, a catalyst, and the above-mentioned filler component. The organic isocyanate component and the active hydrogen-containing component may comprise one or more different types of compounds.

[0031] The organic polyisocyanate component used in the preparation of the polyurethane foam contains at least a polyisocyanate having the general formula Q(NCO) i (wherein i is an integer having an average value of 2 or more, and Q is an organic group having a valence number of i). Q may be a substituted or unsubstituted group (for example, an alkane or aromatic group having an appropriate valence number). Q has the formula Q 1 -Z-Q 1 (wherein Q 1 is an alkylene or arylene group, and Z is -O-, -O-Q 1 -S-, -CO-, -S-, -S-Q 1 -S-, -SO-, or -SO2-). Q may represent a polyurethane group having a valence number of i).

[0032] Examples of suitable polyisocyanates include hexamethylene diisocyanate, 1,8-diisocyanato-p-methane, xylyl diisocyanate, diisocyanatocyclohexane, phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and tolylene diisocyanate including crude tolylene diisocyanate, bis(4-isocyanatophenyl)methane, chlorophenylene diisocyanate, diphenylmethane-4,4'-diisocyanate (also known as 4,4'-diphenylmethane diisocyanate or MDI) and its adducts, naphthalene-1,5-diisocyanate, triphenylmethane-4,4',4''-triisocyanate, isopropylbenzene-alpha-4-diisocyanate, or polymeric isocyanates, for example, polymethylene polyphenyl isocyanate.

[0033] The active hydrogen-containing component comprises at least one polyfunctional active hydrogen-containing compound, which may be a polyamine or polyol, such as a polyether polyol, polyester polyol, low molecular weight polyol, or a combination thereof. Suitable polyester polyols include polycondensation products of a polyol and a dicarboxylic acid or its ester-forming derivative (e.g., anhydrides, esters, and halides), polylactone polyols that can be obtained by ring-opening polymerization of lactones in the presence of a polyol, and polycarbonate polyols that can be obtained by the reaction of a diester carbonate with a polyol or castor oil polyol. Suitable dicarboxylic acids and dicarboxylic acid derivatives useful for producing polycondensed polyester polyols include aliphatic or alicyclic dicarboxylic acids, e.g., glutaric acid, adipic acid, sebacic acid, fumaric acid, or maleic acid; dimer acids; aromatic dicarboxylic acids, e.g., phthalic acid, isophthalic acid, or terephthalic acid; tribasic or more functional polycarboxylic acids, e.g., pyromellitic acid; and anhydrides or secondary alkyl esters, e.g., maleic anhydride, phthalic anhydride, or dimethyl terephthalate. Cyclic ester polymers can also be used. Preparations of cyclic ester polymers from at least one cyclic ester monomer are exemplified in U.S. Patents 3,021,309 to 3,021,317; 3,169,945; and 2,962,524. Suitable cyclic ester monomers include, but are not limited to, δ-valerolactone; ε-caprolactone; zeta-enantholactone; and monoalkyl-valerolactones, such as monomethyl-, monoethyl-, and monohexyl-valerolactone. Generally, polyester polyols may include caprolactone-based polyester polyols, aromatic polyester polyols, ethylene glycol adipate-based polyols, or combinations thereof. Polyester polyols made from ε-caprolactone, adipic acid, phthalic anhydride, and terephthalic acid, or dimethyl esters of terephthalic acid, are generally preferred.

[0034] Polyether polyols are composed of water or polyhydric organic components, such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexylene glycol, 1,10-decanediol, 1,2-cyclohexanediol, 2-butene-1,4-diol, 3-cyclohexene-1,1-dimethanol, 4-methyl-3-cyclohexene-1,1-dimethanol, 3-methylene-1,5-pentanediol, Diethylene glycol, (2-hydroxyethoxy)-1-propanol, 4-(2-hydroxyethoxy)-1-butanol, 5-(2-hydroxypropoxy)-1-pentanol, 1-(2-hydroxymethoxy)-2-hexanol, 1-(2-hydroxypropoxy)-2-octanol, 3-allyloxy-1,5-pentanediol, 2-allyloxymethyl-2-methyl-1,3-propanediol, [4,4-pentyloxy)-methyl]-1,3-propanediol, 3-(o-propenylphenoxy)-1, 2-Propanediol, 2,2'-Diisopropylidenebis(p-Phenyleneoxy)Diethanol, Glycerol, 1,2,6-Hexanetriol, 1,1,1-Trimethylolethane, 1,1,1-Trimethylolpropane, 3-(2-Hydroxyethoxy)-1,2-Propanediol, 3-(2-Hydroxypropoxy)-1,2-Propanediol, 2,4-Dimethyl-2-(2-Hydroxyethoxy)-Methylpentanediol-1,5; 1,1,1-Tris[2-Hydroxyethoxy)methyl]ethane, 1,1 These can be obtained by chemically adding alkylene oxides, such as ethylene oxide, propylene oxide, or combinations thereof, to three-component condensation products, etc., such as 1-tris[2-hydroxypropoxy)-methyl]propane, diethylene glycol, dipropylene glycol, pentaerythritol, sorbitol, sucrose, lactose, alpha-methyl glucoside, alpha-hydroxyalkyl glucoside, novolac polymer, phosphoric acid, benzene phosphoric acid, polyphosphate, for example, tripolyphosphate and tetrapolyphosphate, etc.The alkylene oxides used in the production of polyoxyalkylene polyols may have 2 to 4 carbon atoms or 2 to 3 carbon atoms. Exemplary alkylene oxides include propylene oxide and mixtures of propylene oxide and ethylene oxide. Specifically, polytetramethylene polyetherdiols or glycols, and mixtures with one or more other polyols can be mentioned. The polyols listed above can themselves be used as active hydrogen components.

[0035] Certain classes of polyether polyols are generally defined by the formula R[(OC n H 2n ) z OH] a (wherein R is hydrogen or a polyvalent hydrocarbon group; a is an integer equal to the valence of R (i.e., 2 to 8); n is an integer between 2 and 4 (preferably 3) including an endpoint in each occurrence; and z is an integer with a value between 2 and 200, preferably 15 to 100, in each occurrence) is represented by the formula R[(OC4H8) z It may have OH]2 (wherein R is a divalent hydrocarbon group, and z is 2 to about 40, specifically 5 to 25, in each occurrence).

[0036] Another type of active hydrogen-containing material that can be used is a polymer polyol composition obtained by polymerizing an ethylenically unsaturated monomer and a polyol, as described in U.S. Patent No. 3,383,351, the disclosure of which is incorporated herein by reference. Suitable monomers for producing such compositions include acrylonitrile, vinyl chloride, styrene, butadiene, vinylidene chloride, and other ethylenically unsaturated monomers as specified and described in the U.S. patent mentioned above. Suitable polyols include those listed and described above and in U.S. Patent No. 3,383,351. Active hydrogen-containing components also include polyhydroxy-containing compounds, such as hydroxyl-terminated polyhydrocarbons (US Patent No. 2,877,212); hydroxyl-terminated polyformal (US Patent No. 2,870,097); fatty acid triglycerides (US Patents No. 2,833,730 and 2,878,601); hydroxyl-terminated polyesters (US Patents No. 2,698,838, 2,921,915, 2,591,884, 2,866,762, 2,850,476, 2,602,783, 2,729,618, and 2,7 It may contain (US Patent Nos. 79,689, 2,811,493, 2,621,166, and 3,169,945); hydroxymethyl-terminated perfluoromethylene (US Patent Nos. 2,911,390 and 2,902,473); hydroxyl-terminated polyalkylene ether glycol (US Patent No. 2,808,391; UK Patent No. 733,624); hydroxyl-terminated polyalkylene arylene ether glycol (US Patent No. 2,808,391); and hydroxyl-terminated polyalkylene ether triol (US Patent No. 2,866,774).

[0037] The active hydrogen-containing component, particularly the polyol component, may further include very low molecular weight chain extenders, crosslinkers, or combinations thereof. Exemplary chain extenders and crosslinkers include alkanediols, dialkylene glycols, and / or polyhydric alcohols having a molecular weight of about 200 to 400 daltons, preferably triols and tetrols. The chain extenders and crosslinkers can be used, for example, in amounts of 0.5 to 20 mass percent or 10 to 15 mass percent relative to the total mass of the active hydrogen-containing component. Other chain extenders, but not limited to these, may be very low molecular weight (less than about 200 daltons) diols, including dipropylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, and 3-methyl-1,5-pentanediol.

[0038] In one embodiment, the active hydrogen-containing component is a polyol component comprising a higher molecular weight polyether polyol, for example, a polyether polyol having a mass average molecular weight (Mw) of 500 to about 4,000, or 1,000 and 3,000, and a hydroxyl value of 10 to 200; a polyester polyol, for example, a polycaprolactone-based polyol, or a combination thereof; and a very low molecular weight polyol as a chain extender or crosslinking agent. Exemplary polyether polyols include polyoxyalkylenediols and triols, and polyoxyalkylenediols and triols grafted with polystyrene and / or polyacrylonitrile on the polymer chain, or a combination thereof. A triol, for example, a polycaprolactone triol having an Mw of 50 to 3,000, may also be present, with a hydroxyl value of 200 to 2,000, preferably 500 to 1,500. A preferred triol is a polycaprolactone triol.

[0039] Generally, the average mass percentage hydroxyl of a hydroxyl-containing compound (including all polyols or diols) with respect to its hydroxyl value, including other crosslinking additives, fillers, surfactants, catalysts, and, if used, pigments, can range from 500 to 400, depending on the desired hardness or softness of the polyurethane. The hydroxyl value is defined as the number of milligrams of potassium hydroxide required to completely neutralize the hydrolysis product of a fully acetylated derivative prepared from 1 gram of polyol or polyol component, with or without other crosslinking additives.

[0040] Numerous catalysts can be used to catalyze the reaction between the isocyanate component and the active hydrogen-containing component. The amount of catalyst in the uncured polyurethane foam is 0.001 to 9 wt%, or 0.04 to 9 wt%, or 0.04 to 7 wt%, or 3 to 7 wt%, relative to the total mass of the uncured polyurethane foam. Such catalysts include organic and inorganic salts or organometallic derivatives of bismuth, lead, tin, iron, antimony, uranium, cadmium, cobalt, thorium, aluminum, mercury, zinc, nickel, cerium, molybdenum, vanadium, copper, manganese, or zirconium, as well as phosphines or tertiary organic amines of these metals. Examples of such catalysts include dibutyltin dilaurate, dibutyltin diacetate, tin(I) octanoate, lead octanoate, cobalt naphthenate, bis(2,4-pentanedione)nickel(II) or its derivatives, such as diacetonitrile diacetylacetonate nickel, diphenylnitrile diacetylacetonate nickel, or bis(triphenylphosphine)diacetylacetonate nickel. The catalyst may include iron(III) acetylacetate, triethylamine, triethylenediamine, N,N,N',N'-tetramethylethylenediamine, 1,1,3,3-tetramethylguanidine, N,N,N'N'-tetramethyl-1,3-butanediamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, 1,3,5-tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, o- and p-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, 1,4-diazobicyclo[2.2.2]octane, N-hydroxyl-alkylquaternary ammonium carboxylate, and tetramethylammonium formate, tetramethylammonium acetate, or tetramethylammonium 2-ethylhexanoate. For example, as described in U.S. Patent Nos. 10,023,681, 9,228,047, and 5,733,945, a catalyst delay agent may be optionally present.A combination of at least two different catalysts can be used.

[0041] The reactive composition may include a surfactant that can stabilize the reactive composition before it hardens. The surfactant may include an organosilicon surfactant. Organosilicones consist of SiO2 (silicate) units and (CH3)3SiO 0.5 The (trimethylsiloxy) units may be present in a molar ratio of silicate units to trimethylsiloxy units of 0.8:1 to 2.2:1, or 1:1 to 2.0:1, or may contain copolymers essentially composed of them. The organosilicone may contain a partially crosslinked siloxane-polyoxyalkylene block copolymer, where the siloxane block and polyoxyalkylene block are bonded to carbon by silicon, or from oxygen to carbon by silicon. The surfactant may be present in an amount of 0.5 to 10 wt% or 1 to 6 wt% relative to the total mass of the active hydrogen components. The surfactant may be present in an amount of 0.1 to 7 wt% or 2 to 5 wt% relative to the total mass of the uncured polyurethane foam.

[0042] In addition, optional additives may be added to the reactive composition. For example, additives may include fillers (e.g., alumina trihydrate, silica, talc, calcium carbonate, or clay), drying agents, dyes, pigments (e.g., titanium dioxide or iron oxide), antioxidants, ozone degradation inhibitors, UV stabilizers, conductive fillers, or conductive polymers.

[0043] Methods for manufacturing foams are generally known. Foams can be produced by mechanical foaming, physical or chemical foaming, or both. Polyurethane foams can be produced by mechanically casting foamed compositions. In particular, reactive polyurethane precursors can be mixed, mechanically foamed, and then cast to form layers and cure.

[0044] Physical blowing agents can be used alone, together, or in mixtures with one or more chemical blowing agents. Physical blowing agents can be selected from a wide range of materials, including hydrocarbons, ethers, esters, and partially halogenated hydrocarbons, ethers, and esters. Typical physical blowing agents have a boiling point of -50 to 100°C or -50 to 50°C. Examples of physical blowing agents include CFCs (chlorofluorocarbons) (e.g., 1,1-dichloro-1-fluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, monochlorodifluoromethane, or 1-chloro-1,1-difluoroethane); FCs (fluorocarbons) (e.g., 1,1,1,3,3,3-hexafluoropropane, 2,2,4,4-tetrafluorobutane, 1,1,1,3,3,3-hexafluoro-2-methylpropane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2,2-pentafluoropropane, 1,1,1,2,3-pentafluoropropane, 1,1,2,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane) Examples include ulolopropane, 1,1,1,3,3,4-hexafluorobutane, 1,1,1,3,3-pentafluorobutane, 1,1,1,4,4,4-hexafluorobutane, 1,1,1,4,4-pentafluorobutane, 1,1,2,2,3,3-hexafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, or pentafluoroethane); FE (fluoroethers) (e.g., methyl-1,1,1-trifluoroethyl ether or difluoromethyl-1,1,1-trifluoroethyl ether); or hydrocarbons (e.g., n-pentane, isopentane, or cyclopentane). The physical blowing agent may contain at least one of the following: carbon dioxide, ethane, propane, n-butane, isobutane, pentane, hexane, butadiene, acetone, methylene chloride, chlorofluorocarbon, hydrochlorofluorocarbon, or hydrofluorocarbon. Similar to chemical blowing agents, the physical blowing agent can be used in an amount sufficient to bring the resulting foam to the desired bulk density.Typically, the physical blowing agent is used in an amount of 5-50 wt% or 10-30 wt% relative to the total mass of the reactive composition.

[0045] When a chemical blowing agent is used, it may be water, azo compounds (e.g., azoisobutyronitrile, azodicarbonamide (i.e., azo-bis-formamide), or azodicarboxylate barium); substituted hydrazines (e.g., diphenylsulfone-3,3'-disulfohydrazide, 4,4'-hydroxy-bis-(benzenesulfohydrazide), trihydrazinotriadin, or aryl-bis-(sulfohydrazide)); semicarbazides (e.g., p-trine sulfo The chemical blowing agent may contain at least one of the following: nilsemicarbazide or 4,4'-hydroxy-bis-(benzenesulfonyl semicarbazide); triazole (e.g., 5-morpholyl-1,2,3,4-thiatriazole); N-nitroso compounds (e.g., N,N'-dinitrosopentamethylenetetramine or N,N-dimethyl-N,N'-dinitrosofthalmid); benzoxazine (e.g., isatoic anhydride); or mixtures (e.g., sodium carbonate / citric acid mixture). The chemical blowing agent may contain water. The blowing agent may contain at least one of the following: ammonium salt, phosphate, polyphosphate, borate, polyborate, sulfate, urea, urea-formaldehyde resin, dicyandiamide, or melamine.

[0046] The amount of the aforementioned chemical blowing agent varies depending on the agent and the desired foam density, and can be easily determined by those skilled in the art. Generally, these chemical blowing agents are used in amounts of 0.1 to 10 wt% of the total mass of the reactive composition. The decomposition products formed during the decomposition process may be physiologically safe and may not have any significantly detrimental effect on the thermal stability or mechanical properties of the foamed polyurethane sheet.

[0047] In one embodiment, polyurethane foam is produced by mechanically mixing a reactive composition (containing an isocyanate component, an active hydrogen-containing component, a foam-stabilizing surfactant, a catalyst, and other optional additives) with a foam-forming gas. The foaming mixture can be supplied onto a release liner and applied to a layer of desired thickness by a doctor blade or other suitable application device. The gauge layer of the foaming mixture can then be delivered to one or more heating zones. After the heating zones, the formed polyurethane layer can be passed through a cooling zone.

[0048] For example, in the manufacture of polyurethane foam, the reactive component of the polyurethane foam-forming composition can be formulated in two parts: one part ("Part A") contains an active hydrogen-containing component, and sodium borate, a catalyst, a surfactant, and an inhibitor if used, and a chemical blowing agent; the other part ("Part B") contains an organic isocyanate component. Both parts are weighed, mixed, and may be cast, for example, into a mold or a continuous coating line. Foam formation and curing then occur in either the mold or the continuous coating line. In the manufacturing method, the reactive component of the polyurethane foam-forming composition can be introduced into an extruder together with sodium borate and a chemical blowing agent, a physical blowing agent, or other additives if used. The catalyst can then be weighed into the extruder to initiate the foam formation and curing reaction. By using a physical blowing agent such as liquid nitrogen dioxide or supercritical carbon dioxide in combination with a chemical blowing agent such as water, much lower density foams can be produced.

[0049] In one embodiment, an uncured polyurethane foam can be formed by combining 70-90 wt% or 75-89 wt% of an active hydrogen-containing component ("Part A") and 10-30 wt% or 11-25 wt% of an isocyanate component ("Part B"). In one embodiment, sodium borate may also be added to Part B.

[0050] Optionally, the thermal control sheet can be immersed in water for a certain period of time, for example 24 hours, to allow it to absorb water. The high heat capacity of liquid water can contribute to significantly delaying heat transfer from one side of the thermal control sheet to the other.

[0051] The desired degree of heat shielding properties can be achieved by varying the amount of sodium borate. The uncured polyurethane foam may contain 3 to 68 wt% or 14 to 36 wt% sodium borate relative to the total mass of the uncured polyurethane foam.

[0052] During oven curing, some of the bound water in the sodium borate may be released by the heat of the oven. This additional water may increase the number of active OH groups, and the additional isocyanate moieties may aid in the curing of the foam. Contrary to the calculated stoichiometric ratio of 1:1 for the active hydrogen-containing groups of the isocyanate moieties in the uncured polyurethane foam, e.g., for the hydroxyl groups, a stoichiometric ratio of 0.85:1 to 1.40:1 or 1.00:1 to 1.20:1 for the active hydrogen-containing groups of the isocyanate moieties in the uncured polyurethane foam, e.g., for the hydroxyl groups, e.g., for the hydroxyl groups, e.g., a stoichiometric ratio of 0.85:1 to 1.40:1 or 1.00:1 to 1.20:1 can be used.

[0053] Polyurethane foam-forming compositions can be foamed and cured in the presence of reinforcing fibers that provide fiber reinforcement. Examples of reinforcing fibers include polyester, oxidized polyacrylonitrile, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass fiber (e.g., E-glass, S-glass, D-glass, L-glass, quartz fiber, or combinations thereof), high-density polyolefin, ceramics, acrylic, fluoropolymer, polyurethane, polyamide, polyimide, etc., or combinations thereof. The reinforcing fibers may be in any preferred form, for example, woven or non-woven mats or tapes. The mats or tapes may have thicknesses of, for example, 0.005 to 10 mm, or 0.05 to 8 mm, or 0.25 to 6 mm, or 0.5 to 10 mm, or 0.25 to 10 mm, or 0.5 to 10 mm, or 1 to 10 mm, or 1 mm to 6 mm. Combinations of reinforcing granular materials and reinforcing fibers can be used.

[0054] The thermal management sheet may have a void volume of 5-99% of the total volume of the foam, for example, 30% or more.

[0055] Thermal management sheets are flexible and can maintain their elastic behavior, which is a property reflected by the compressive deflection and compression set of the foam, over many cycles of compression deflection throughout the battery life. Foam with good compression set resistance provides cushioning and maintains its original shape or thickness under load over a long period of time. In one embodiment, thermal management sheets, for example, cured polyurethane foam, have compressive deflections of 0.2 to 125 pounds / square inch (psi) (1 to 862 kilopascals (kPa)), or 0.25 to 20 psi (1.7 to 138 kPa), or 0.5 to 10 psi (3.4 to 68.90.5 kPa), determined according to ASTM D3574-17, each with 25% deflection. A heat-controlled sheet, such as a cured polyurethane foam, may have a compression set of 0-15%, or 0-10%, or 0-5%, or greater than 0-15%, or greater than 0-10%, or greater than 0-5%, as determined at 70°C according to ASTM D3574-95 Test D.

[0056] In one embodiment, the thermal control sheet is used as a single layer. However, multiple single layers can be stacked and used as a single layer. Other layers, such as flame retardant layers, non-porous elastomer barrier layers, adhesive layers, etc., or combinations thereof, can be used in combination with the thermal control sheet. However, one advantage of the thermal control sheet is that a single sheet used alone can be effective without other layers, even if it is as thin as 1-30 mm, or 1-20 mm, or 1-15 mm, or 1-10 mm, or 1-8 mm, or even 1-6 mm.

[0057] When used, the flame retardant layer may include flame retardant inorganic materials, such as boehmite, aluminum hydroxide, magnesium hydroxide, an expanding material, or a combination thereof. The expanding material may include an acid source, a blowing agent, and a carbon source. Each component may exist in separate layers or as a mixture, for example, as a closely spaced mixture. For example, the expanding material may include an acid source, a blowing agent, and a carbon source. For example, when the temperature reaches a value of, for example, 200-280°C, an acidic species (e.g., polyphosphate) may react with a carbon source (e.g., pentaerythritol) to form char. When the temperature rises to, for example, 280-350°C, the blowing agent then decomposes to produce gaseous products, which cause the char to expand.

[0058] Examples of acid sources include organic or inorganic phosphorus compounds, organic or inorganic sulfates (e.g., ammonium sulfate), or combinations thereof. Examples of organic or inorganic phosphorus compounds include organophosphates or organophosphonates (e.g., tris(2,3-dibromopropyl)phosphate, tris(2-chloroethyl)phosphate, tris(2,3-dichloropropyl)phosphate, tris(1-chloro-3-bromoisopropyl)phosphate, bis(1-chloro-3-bromoisopropyl)-1-chloro-3-bromoisopropylphosphonate, polyaminotriazine phosphate, melamine phosphate, triphenyl phosphate, or guanylurea phosphate); organophosphite esters (e.g., trimethyl phosphite or triphenyl phosphite); phosphazenes (e.g., hexaphenoxycyclotriphosphazene); phosphorus-containing inorganic compounds (e.g., phosphoric acid, phosphorous acid, phosphite, urea phosphate, ammonium phosphate (e.g., ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, or ammonium polyphosphate)); or combinations thereof.

[0059] The foaming agent may include a substance that decomposes at temperatures above 120°C, for example, 120-200°C or 130-200°C (for example, into smaller compounds such as ammonia or carbon dioxide). Examples of foaming agents include dicyandiamide, azodicarbonamide, melamine, guanidine, glycine, urea (for example, urea-formaldehyde resin or methylolated guanylurea phosphate), halogenated organic materials (for example, chlorinated paraffin), or combinations thereof.

[0060] The expanding material may contain a carbon source. The polyurethane foam layer may function as a carbon source. Examples of carbon sources include dextrin, phenol-formaldehyde resin, pentaerythritol (e.g., its dimer or trimer), clay, polymers (e.g., polyamide 6, amino-poly(imidazoline-amide), or polyurethane), or combinations thereof. Amino-poly(imidazoline-amide) may contain repeated amide bonds and imidazoline groups.

[0061] The expanding material optionally further comprises a binder. Examples of binders include epoxy, polysulfide, polysiloxane, polysylarylene, or combinations thereof. The binder may be present in the expanding material in amounts of 50 wt% or less, 5-50 wt%, or 35-45 wt% relative to the total mass of the expanding material. The binder may also be present in the expanding material in amounts of 5-95 wt% or 40-60 wt% relative to the total mass of the expanding material.

[0062] The expanding material may optionally include synergistic compounds that further improve the flame retardancy of the expanding material. Examples of synergistic compounds include boron compounds (e.g., zinc borate, boron phosphate, or boron oxide), silicon compounds, aluminosilicates, metal oxides (e.g., magnesium oxide, iron(II) oxide, or aluminum oxide hydrate (boehmite)), metal salts (e.g., alkali metal or alkaline earth metal salts of organosulfonic acids, or alkaline earth metal carbonates), or combinations thereof. A synergistic combination may include a phosphorus-containing compound and at least one of the aforementioned.

[0063] The flame retardant layer may further contain char-forming agents, such as lignin, boehmite, clay nanocomposite, expandable graphite, pentaerythritol, cellulose, nanosilica, ammonium polyphosphate, lignosulfonate, melamine, cyanurate, zinc borate, hanthite, hydromagnesite, or combinations thereof. Without being bound by theory, it is thought that, like expandable materials, char-forming agents can reduce flame spread using two energy absorption mechanisms, including char formation and subsequent char expansion.

[0064] The flame-retardant layer may further contain polymer binders, such as silicone, polyurethane, ethylene-vinyl acetate, ethylene-methyl acrylate, ethylene-butyl acrylate, or combinations thereof. The flame-retardant layer may have a thickness of 0.1 to 2 mm, 0.5 to 1.5 mm, or 0.8 to 1.1 mm.

[0065] When used, the non-porous elastomer barrier layer is measured at 25°C and 1 atm, respectively, and has a density of 20 g-mm / m². 2 Less than 10g-mm / m² per day, or 10g-mm / m² 2 Less than 5 g-mm / m² per day, or 5 g-mm / m². 2 The material comprises an elastomer having a water permeability coefficient of less than 1 / day; or a tensile stress of 0.5 to 15 megapascals at 100% elongation measured at 21°C according to ASTM 412; or a combination thereof. The nonporous elastomer barrier layer may have a thickness of 0.25 to 1 mm or 0.4 to 0.8 mm.

[0066] The non-porous elastomer barrier layer may contain a hydrophobic elastomer material to prevent the permeation of water or water vapor. For example, the elastomer barrier layer may contain a thermoplastic elastomer (TPE), provided that it has the desired hydrophobicity (lack of water or water vapor permeability). Classes of TPE include styrene-based block copolymers (TPS or TPE-s), (TPO or TPE-o), thermoplastic vulcanized products (TPV or TPE-v), thermoplastic polyurethanes, thermoplastic copolyesters (TPC or TPE-E), thermoplastic polyamides (TPA or TPE-A), and the like.

[0067] Examples of elastomer materials that can be used include acrylic rubber, butyl rubber, halogenated butyl rubber, copolyester, epichlorohydrin rubber, ethylene-acrylic rubber, ethylene-butylacrylic rubber, ethylene-diene rubber (EPR), for example, ethylene-propylene rubber, ethylene-propylene-diene monomer rubber (EPDM), ethylene-vinyl acetate, fluoroelastomer, perfluoroelastomer, polyamide, polybutadiene, polychloroprene, polyolefin rubber, polyisoprene, polysulfide rubber, natural rubber, nitrile rubber, low-density polyethylene, polypropylene, thermoplastic polyurethane elastomer (TPU), silicone rubber, fluorinated silicone rubber, styrene-butadiene, styrene-isoprene, vinyl rubber, or combinations thereof. In one embodiment, the non-porous elastomer barrier layer includes ethylene-propylene-diene monomer rubber, polychloroprene, or combinations thereof.

[0068] Adhesive layers may be present to bond the thermal control sheet to another thermal control sheet, another type of layer, or components of a cell array or battery. A variety of suitable adhesives can be used in the thermal control sheet. The adhesive can be selected in terms of ease of application and stability under battery operating conditions. Each adhesive layer may be the same or different, and may be the same or different thickness. Suitable adhesives include phenolic resins, epoxy adhesives, polyester adhesives, fluorinated polyvinyl adhesives, acrylic or methacrylic adhesives, or silicone adhesives, preferably acrylic or silicone adhesives. In one embodiment, the adhesive is a silicone adhesive. Solvent cast, hot melt, and two-part adhesives can be used. Each adhesive layer may independently have a thickness of 0.00025 to 0.010 inches (0.006 to 0.25 mm) or 0.0005 to 0.003 inches (0.01 to 0.08 mm).

[0069] If the thermal control sheet includes an adhesive layer, the thermal control sheet may further include a release layer. “Release layer” means any single layer containing a release coating, optionally supported by one or more additional layers containing a release liner. The thickness of each release layer may be 5–150 micrometers (μm), 10–125 μm, 20–100 μm, 40–85 μm, or 50–75 μm.

[0070] A thermal management sheet is placed on an electrochemical cell to provide a battery cell assembly. The cell can be a lithium-ion cell, particularly a prismatic, cylindrical, or pouch cell. Figure 2 shows one configuration of the thermal management sheet arrangement in cell assembly 1002, and Figure 3 shows one configuration of the thermal management sheet arrangement in cell assembly 1003. Figures 2 and 3 show that the thermal management sheet 10 can be placed between a first cell 103 and a second cell 104. Figure 2 shows that the thermal management sheet 10 can be approximately the same size as the height and width of cells 103 and 104. Figure 3 shows that the thermal management sheet 10 can be smaller than each of the cells 103 and 104. As also shown in Figure 3, the thermal management sheet 10 can also extend beyond the edges of the electrochemical cells 103 and 104. A thermal management sheet extending beyond the edges of the electrochemical cell can wrap around and cover all of at least another portion or another face of the cell.

[0071] Figure 4 shows that a multi-cell assembly 1004 may include more than two cells 103, 104, with thermal management sheets 10 placed between each of the cells 103, 104. The cells may be lithium-ion cells, particularly pouch cells. Figure 4 shows that a battery assembly 1004 may include more than two cells (e.g., 103, 104), with thermal management sheets 10 placed between each of the cells 103, 104 and each of the other cells. In one embodiment, 2 to 10 thermal management sheets may be installed on the cells or in the cell array during the manufacture of the battery assembly 1004. For example, 2 to 10 thermal management sheets may be installed inside the battery, for example, facing the electrodes, or externally facing the outside of the battery. 2 to 10 thermal management sheets may be installed or bonded to the cells or the pouch of the pouch cells, or both. Naturally, one or more than 10 thermal management sheets may be present depending on the number of cells and cell arrays. Figure 4 further shows a thermal management sheet 10a installed on the outside of the battery assembly 1004, facing the outside of the battery.

[0072] In one embodiment, at least a portion of the exposed outer edge of the thermal control sheet may include a material 88 that removes heat from the body of the thermal control sheet. Exemplary materials to be applied to the exposed edge of the thermal control sheet include ceramics, e.g., boron nitride or aluminum nitride, metals, e.g., aluminum, high heat capacity waxes, phase change materials, etc., or combinations thereof.

[0073] Cell assemblies are used in batteries. A battery includes a housing that at least partially encloses one or more electrochemical cells or cell arrays. The housing can be of any preferred type, e.g., polymer or pouch of pouch cells. Thermal control sheets can be placed on or directly on the cells or cell arrays in the battery in any preferred configuration. Thermal control sheets may be placed between individual cells or cell arrays in the battery. Thermal control sheets may be placed, for example, next to, on a portion of, or on a selected set of cells or cell arrays in the battery, between them, below them, adjacent to them, or in combination thereof. Thermal control sheets may be placed on or bonded to multiple pouch cells, pressure control pads, cooling plates, or other internal battery components. The assembly pressure of the battery can maintain the stacked components in place.

[0074] For example, as shown in Figure 5, the battery 2001 may contain multiple cells in multiple cell arrays 960 inside the housing 965. The thermal management sheet 10 can be installed between two cell arrays 960. Furthermore, as shown in Figure 5, the thermal management sheet 10 can be installed between the side of the housing 965 and the side of the cell arrays 960, along multiple cells of the cell arrays. Also, as shown in Figure 5, the thermal insulation sheet 10 can be installed between the end of the housing 965 and the end of one or more cell arrays 960.

[0075] If more than one thermal control sheet or other layer is used, the sheets and layers can be assembled by a preferred method. The sheets and layers can be assembled on the surface of the cell or other components of the battery (e.g., the wall of the battery case). In one embodiment, the sheets and layers are assembled separately and then placed or bonded to the cell, battery components, or both. Each sheet or layer can be manufactured separately and then stacked in a desired order (e.g., placed or bonded using one or more adhesive layers). Alternatively, one or more individual layers can be manufactured by laminating them on other individual layers, for example, by coating, casting, or using heat and pressure. For example, in one embodiment, the flame retardant layer or adhesive layer may be cast directly onto the thermal control sheet, or the thermal control sheet may also be cast directly onto the flame retardant layer. Direct coating or casting can reduce thickness and improve flame retardancy by eliminating the adhesive layer.

[0076] The following examples are provided to illustrate the present disclosure. The examples are for illustrative purposes only and are not intended to limit the devices fabricated in accordance with the present disclosure to the materials, conditions, or process parameters shown in the examples. [Examples]

[0077] The materials listed in Table 1 were used in the examples.

[0078] Table 1 [Table 1]

[0079] Sample preparation Samples were prepared by creating two-component formulations having part A (containing a polyol) and part B (containing isocyanate (ISO)) as shown in Tables 2-7 (Tables 2-8). In Tables 2-7 (Tables 2-8), "isocyanate" refers to the molar ratio of the isocyanate portion to the hydroxyl groups.

[0080] Examples 1-7 and Comparative Examples 3-21 were prepared by preparing 100-300 gram batches of Part A and foaming Part A. An appropriate amount of Part B was added, and the mixture was further foamed. The foamed mixture was then poured onto the release layer of the casting line. The foamed mixture was applied to a layer of the desired thickness using a doctor blade and cured. The amounts shown in Tables 2-7 (Tables 2-8) are in parts by mass.

[0081] For Examples 8-19, 9a, 10a-10c and 11a-11i, and Comparative Examples 22-26 and 1a, 16-32 kilogram batches of part A were prepared. Both parts A and B were pumped into a mix head in an appropriate ratio, foamed together, and then dispensed onto a casting line through a nozzle. Air could be blown into the mix head, and the density could be controlled more effectively compared to Examples 1-7 and Comparative Examples 3-21. Comparative Examples 1-2 are production samples, which are produced in the same manner as Examples 8-14 and Comparative Examples 22-26, except for larger quantities.

[0082] Table 2A [Table 2]

[0083] Table 2B [Table 3]

[0084] Table 3 [Table 4]

[0085] Table 4 [Table 5]

[0086] Table 5 [Table 6]

[0087] Table 6 [Table 7]

[0088] Table 7 [Table 8]

[0089] Thermal test The thermal performance of the sample was determined by thermal runaway simulation. Figure 6 shows the apparatus 5000 used in the thermal test. The thermal control sheet 10 was placed on a hot plate 990 set to 550°C. A 12.7 mm mica plate cell analog 970 was placed on the top surface of the thermal control sheet 10. A thermocouple sensor 980 was inserted into a hole drilled in the mica plate cell analog 970, and the thermocouple sensor 980 was placed on the top surface of the thermal control sheet 10. The thermal control sheet was wrapped in a sheet of aluminum foil, with one layer of aluminum foil between the hot plate and the thermal control sheet, and another layer of foil between the thermal control sheet and the mica plate.

[0090] Referring to Figure 7, Comparative Example 1 does not provide thermal runaway protection and has no flammability rating. Comparative Example 2 has a polyol / ISO composition similar to Comparative Example 1, but with the addition of 20 parts of expandable graphite and has an HBF flammability rating. Comparative Examples 1 and 2 do not perform as desired in the hot plate test.

[0091] Referring to Figure 8, Examples 1 and 2, and Comparative Examples 3-6, had similar polyol / ISO formulations, but the filler compositions varied. Comparative Example 3 contained ATH, Comparative Example 4 contained zinc borate, Comparative Example 5 contained ATH and zinc borate, Comparative Example 6 contained APB, Example 1 contained sodium borate, and Example 2 contained sodium borate and zinc borate. Examples 1 and 2 performed better than Comparative Examples 3-6 in the hot plate test.

[0092] Referring to Figure 9, Example 3 contained 36 parts sodium borate in part A, Example 4 contained 30 parts sodium borate in part A, Example 5 contained 20 parts sodium borate in part A, Example 6 contained 10 parts sodium borate in part A, and Example 7 contained 5 parts sodium borate in part A. The performance of the hot plate test improved with increasing amounts of sodium borate added.

[0093] Referring to Figure 10, Example 3 contained 36 parts sodium borate in part A, Example 4 contained 30 parts sodium borate in part A, Example 5 contained 20 parts sodium borate in part A, Example 6 contained 10 parts sodium borate in part A, and Example 7 contained 5 parts sodium borate in part A. The temperature of the hot plate at 10 minutes decreased with increasing amounts of sodium borate added.

[0094] Referring to Figure 11, Comparative Example 7 contained 36 parts lignin in part A, Comparative Example 13 contained 18 parts sodium borate and 18 parts lignin in part A, Comparative Example 14 contained 18 parts zinc borate and 18 parts lignin in part A, and Comparative Example 15 contained 18 parts MC-APP and 18 parts lignin in part A. Combining sodium borate, zinc borate, or MC-APP with lignin, which is a carbon-forming filler, did not improve the hot plate test performance.

[0095] Referring to Figure 12, Comparative Example 8 contains 26 parts sodium borate and 10 parts sodium silicate in part A; Comparative Example 9 contains 10 parts sodium borate and 26 parts silica in part A; Comparative Example 10 contains 18 parts sodium borate and 18 parts expansive graphite in part A; Comparative Example 11 contains 18 parts sodium borate and 18 parts MC-APP in part A; Comparative Example 12 contains 18 parts sodium borate and 18 parts SC-APP in part A; and Comparative Example 13 contains 18 parts sodium borate and 18 parts lignin in part A.

[0096] Compared to Example 6, which contained 10 parts sodium borate (see Figures 9 and 10), the addition of 26 parts pulverized silica in Comparative Example 9 had no effect. Comparative Example 8, which contained 10 parts sodium silicate in addition to 26 parts sodium borate, performed worse than Example 3, which had equivalent thickness and density (see Figures 9 and 10). With the same amount of filler added (36 parts in part A), the case where all the filler is sodium borate is superior to the case where sodium borate is used in combination with sodium silicate, expandable graphite, MC-APP, or SC-APP.

[0097] The thermal test results suggest that the adhesion of the formed coal layer may not improve with the addition of silicon-containing raw materials. Based on the thermal test results, and without being bound by theory, it can be considered that the formation of borosilicate coal may not be a suitable mechanism for blocking heat transfer in the heat control sheet containing sodium borate. Nail penetration tests were not performed in Comparative Examples 8 and 9.

[0098] Referring to Figure 13, Comparative Example 16 includes MC-APP, and Comparative Example 17 includes SC-APP. Neither MC-APP nor SC-APP improves the hot plate test performance.

[0099] Referring to Figure 14, Comparative Example 18 contains aerogel, Comparative Example 19 contains calcium sulfate dihydrate, Comparative Example 20 contains calcium oxalate monohydrate (which releases CO and CO2 when thermally decomposed), and Comparative Example 21 contains PCM. Aerogel, calcium sulfate dihydrate, calcium oxalate monohydrate, and PCM all, like Comparative Example 1, did not improve the hot plate test performance and reached temperatures exceeding 300°C.

[0100] Referring to Figure 15, Example 13 contained 18 parts sodium borate and 18 parts ATH, Example 14 contained 18 parts sodium borate and 18 parts zinc borate, Comparative Example 22 contained 36 parts MC-APP, Comparative Example 23 contained 36 parts zinc borate, Comparative Example 24 contained 18 parts zinc borate and 18 parts ATH, and Comparative Example 25 contained 36 parts ATH. Comparative Example 26 contained 18 parts sodium borate and 18 parts expandable graphite. In the hot plate test, Examples 13 and 14 performed relatively better than Comparative Examples 22, 24, and 25, maintaining a temperature of 260°C or lower after 10 minutes. Comparative Examples 23 and 26 performed relatively well in the hot plate test and nail penetration test, but their performance was inferior to Examples 13 and 14, achieving delays of 27.6 seconds and 31.8 seconds, respectively, compared to 42 seconds and 37.8 seconds for Examples 13 and 14 (see Table 9 (Table 10)).

[0101] Referring to Figure 16, Example 15 contained 5 parts of sodium borate, Example 16 contained 10 parts of sodium borate, Example 17 contained 20 parts of sodium borate, Example 18 contained 36 parts of sodium borate, and Example 19 contained 40 parts of sodium borate. The performance of the hot plate test improved with increasing amounts of sodium borate added.

[0102] Figure 17 shows the results of the hot plate test for Examples 11a to 11i, with a graph of temperature (°C) versus thickness (inches) at 10 minutes. The hot plate test performance improved with increasing density.

[0103] Figure 18 shows a graph of temperature (°C) versus density (PCF) at 10 minutes, illustrating the results of the hot plate test for Examples 11a to 11i. The performance of the hot plate test improved with increasing thickness.

[0104] Figure 19 shows graphs of temperature (°C) versus density (PCF) at 10 minutes, illustrating the results of the hot plate test for Comparative Example 1a and Examples 9a, 10a, 10b, 10c, 11a, 11e, and 11h. The hot plate test performance improved with increasing amounts of sodium borate added.

[0105] Figure 20 shows the results of the hot plate test for Examples 9a, 10b, and 11a, with graphs of temperature (°C) versus sodium borate at 10 minutes. The performance of the hot plate test improved with increasing amounts of sodium borate added.

[0106] Figure 21 shows the results of the hot plate test for Comparative Example 1a and Examples 9a, 10a-10c, and 11a-11i, comparing temperature (°C) to sodium borate mass / mm³ at 10 minutes. 2 This is a graph. The performance of the hot plate test is measured by the mass / mm³ of sodium borate. 2 It improved as [something] increased.

[0107] Nail-piercing test A nail-piercing test was conducted. Figures 22A and 22B are exploded and non-exploded views, respectively, of the first apparatus 7000 for the nail-piercing test, which includes aluminum end plates 910 and 920 (with dimensions of 185 mm × 90 mm × 15.2 mm), polytetrafluoroethylene insulation films 930 and 940 (with dimensions of 185 mm × 90 mm × 1 mm), pouch cells 201 and 202, and a test sample 950 (e.g., a composite thermal management sheet). The characteristics of cells 201 and 202 are shown in Table 8 (Table 9). Cell 201 was pierced by inserting an 8 mm nail at a press-in speed of 10 mm / s to initiate thermal runaway. Cells 201 and 202 were electrically isolated. Temperature profiles were measured using multiple thermocouples. The voltages of cells 201 and 202 were measured. The nail-piercing delay was defined as the time difference between the voltage drop in cell 201 and the voltage drop in cell 202.

[0108] Table 8 [Table 9]

[0109] Figure 23 shows the results of the hot plate test for Examples 9a, 10b, and 11a, specifically the nail-piercing delay (s) versus sodium borate portion, in graph form. The performance of the nail-piercing test improved with increasing amounts of sodium borate added.

[0110] Figure 24 is a graph of nail penetration delay (s) versus thickness showing the results of the hot plate test for Examples 11a to 11i. The nail penetration test performance improved with increasing density.

[0111] Figure 25 is a graph of nail penetration delay (s) versus density showing the results of the hot plate test for Examples 11a to 11i. The performance of the nail penetration test improved with increasing thickness.

[0112] Table 9 [Table 10]

[0113] Example 11 contained 36 parts sodium borate in part A, Example 13 contained 18 parts ATH and 18 parts sodium borate in part A, and Example 14 contained 18 parts zinc borate and 18 parts sodium borate in part A. At comparable thickness and density, Examples 13 and 14 performed slightly better than Example 11 in the nail-piercing test, and in the hot plate test, Examples 11, 13, and 14 each maintained a temperature of 260°C or less at 10 min. Comparative Examples 22, 23, 24, 25, and 26 contained 36 parts MC-APP, 36 parts zinc borate, 18 parts zinc borate and 18 parts ATH, 36 parts ATH, and 18 parts expandable graphite and 18 parts sodium borate, respectively. These comparative examples did not perform as well as Examples 11, 13, and 14 in the nail-piercing test.

[0114] The following are non-limiting aspects of this disclosure.

[0115] Embodiment 1: A method for forming a battery thermal management sheet containing cured polyurethane foam, comprising the steps of: forming an uncured polyurethane foam by combining an active hydrogen-containing component containing a polyol and an isocyanate component containing a polyisocyanate; and curing the uncured polyurethane foam to form a cured polyurethane foam, wherein the uncured polyurethane foam contains, in proportion to the total mass of the uncured polyurethane foam, 3 to 68 mass percent or 14 to 36 mass percent of sodium borate, 0.1 to 7 mass percent or 2 to 5 mass percent of a surfactant, and 0.001 to 9 mass percent A method comprising, or 0.04 to 9 mass percent, or 0.04 to 7 mass percent, or 3 to 7 mass percent of a catalyst, wherein the cured polyurethane foam has a density of 12 to 35 pounds / cubic foot (192 to 561 kilograms / cubic meter) or 15 to 20 pounds / cubic foot (240 to 320 kilograms / cubic meter), and the cured polyurethane foam has a thickness of 1 to 30 mm, or 1 to 20 mm, or 1 to 15 mm, or 1 to 10 mm, or 1 to 8 mm, or 1.5 to 8 mm, or 1.5 to 6 mm, or 2 to 4 mm.

[0116] Embodiment 2: The method according to Embodiment 1, wherein the uncured polyurethane foam further comprises 0 to 33 mass percent, or greater than 0 to 33 wt%, or 7 to 18 mass percent of aluminum hydroxide based on the total mass of the uncured polyurethane foam.

[0117] Embodiment 3: The method according to Embodiment 1 or 2, wherein the uncured polyurethane foam further comprises 0 to 33 mass percent, or greater than 0 to 33 wt%, or 7 to 18 mass percent of zinc borate, based on the total mass of the uncured polyurethane foam.

[0118] Embodiment 4: The method according to any one of Embodiments 1 to 3, wherein the uncured polyurethane foam further comprises 0 to 33 mass percent, or greater than 0 to 33 wt%, or 6 to 18 mass percent of aluminum hydroxide, and 0 to 33 mass percent, or greater than 0 to 33 wt%, or 6 to 18 mass percent of zinc borate, based on the total mass of the uncured polyurethane foam.

[0119] Embodiment 5: The method according to Embodiment 1 or 3, wherein the uncured polyurethane foam contains 0 mass percent of aluminum hydroxide relative to the total mass of the uncured polyurethane foam.

[0120] Embodiment 6: The method according to Embodiment 1 or 2, wherein the uncured polyurethane foam contains 0 mass percent zinc borate relative to the total mass of the uncured polyurethane foam.

[0121] Embodiment 7: The method according to Embodiment 1, wherein the uncured polyurethane foam contains 0 mass percent of aluminum hydroxide and 0 mass percent of zinc borate, based on the total mass of the uncured polyurethane foam.

[0122] Embodiment 8: The method according to any one of Embodiments 1 to 7, wherein the step of combining the active hydrogen-containing component and the isocyanate component comprises combining 70 to 90 percent by mass or 75 to 89 percent by mass of the active hydrogen-containing component and 10 to 30 percent by mass or 11 to 25 percent by mass of the isocyanate component, based on the total mass of the composition.

[0123] Embodiment 9: The method according to any one of Embodiments 1 to 8, wherein the stoichiometric ratio of the isocyanate moiety to the hydroxyl groups in the uncured polyurethane foam is 0.85:1 to 1.40:1 or 1.00:1 to 1.20:1.

[0124] Embodiment 10: The method according to any one of Embodiments 1 to 9, further comprising the step of forming an uncured polyurethane foam by foaming, physically foaming, chemically foaming, or a combination thereof.

[0125] Embodiment 11: A thermal management sheet for a battery formed by any of the methods of the preceding embodiments.

[0126] Embodiment 12: The thermal management sheet for a battery according to Embodiment 11, wherein the thermal management sheet is made of cured polyurethane foam.

[0127] Embodiment 13: A thermal control sheet according to Embodiment 11 or 12, wherein the cured polyurethane foam has a compressive deflection of 0.2 to 125 pounds / square inch, or 1 to 36 pounds / square inch, or 3 to 30 pounds / square inch, as determined in accordance with ASTM D3574, each with a 25% deflection.

[0128] Embodiment 14: A thermal control sheet according to any one of Embodiments 11 to 13, wherein the cured polyurethane foam has a compression set of 0-15%, or 0-10%, or 0-5%, or greater than 0-15%, or greater than 0-10%, or greater than 0-5%, as determined at 70°C according to ASTM D3574-95 Test D.

[0129] Embodiment 15: A battery assembly comprising a thermal control sheet according to any of Embodiments 11 to 14 on the surface of an electrochemical cell.

[0130] Embodiment 16: The battery assembly according to Embodiment 15, wherein the assembly comprises at least two electrochemical cells.

[0131] Embodiment 17: A battery comprising the battery assembly described in Embodiment 16, and a housing that at least partially encloses the battery assembly.

[0132] Embodiment 18: An uncured polyurethane foam comprising a polyol; polyisocyanate; 3 to 68 mass percent or 14 to 36 mass percent of sodium borate; 0.1 to 7 mass percent or 2 to 5 mass percent of a surfactant; and 0.001 to 9 mass percent, or 0.04 to 9 mass percent, or 0.04 to 7 mass percent, or 3 to 7 mass percent of a catalyst, wherein the mass percentage is relative to the total mass of the uncured polyurethane foam composition.

[0133] Compositions, methods, and articles may, by substitution, consist of, or essentially consist of any suitable material, process, or component disclosed herein. Compositions, methods, and articles may be further or alternatively designed to exclude, or substantially exclude, any material(s), process, or component that is otherwise not essential to achieving the function or purpose of the composition, method, or article.

[0134] The terms “one (a)” and “one (an)” do not indicate a limit on quantity, but rather indicate the presence of at least one of the referenced items. The term “or” means “and / or” unless the context clearly indicates otherwise. Throughout this specification, references to “one aspect,” “another aspect,” etc., mean that a particular element (e.g., feature, structure, process, or characteristic) described in relation to that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. Furthermore, it should be understood that the elements described may be combined in various aspects in any suitable manner.

[0135] When an element such as a layer, film, region, or substrate is referred to as being "on top of" another element, it may be directly on top of the other element, or there may be an intervening element. In contrast, when an element is referred to as being "directly on top of" another element, there is no intervening element.

[0136] Unless otherwise specified herein, all test standards are the most current standards in effect as of the filing date of this application, or, if priority is claimed, as of the filing date of the earliest priority application in which the test standard appears.

[0137] The endpoints of all ranges covering the same component or property include the endpoints, are independently combinable, and include all intermediate points and ranges. For example, the range “up to 25 wt%, or 5 to 20 wt%” includes the endpoints and all intermediate values ​​in the “5 to 25 wt%” range, e.g., 10 to 23 wt%, etc. The terms “primary,” “secondary,” etc., “principal,” “secondary,” etc., when used herein, do not indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The term “combinations of those” is open and means that the list includes each element individually, as well as combinations of two or more elements in the list, and combinations of at least one element in the list with similar elements not listed. The term “combination” also includes blends, mixtures, alloys, reaction products, etc.

[0138] Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this disclosure pertains.

[0139] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, in the event of any conflict or inconsistency between the terms of this application and the terms of the incorporated references, the terms of this application shall prevail over the conflicting terms of the incorporated references.

[0140] In the drawings, the widths and thicknesses of layers and regions may be exaggerated for the sake of clarity and explanation in this specification. Similar reference numerals in the drawings refer to similar elements.

[0141] Exemplary embodiments are described herein with reference to schematic cross-sectional views of ideal embodiments. Therefore, variations from the exemplary shapes are to be expected, for example, as a result of manufacturing techniques and / or durability. Accordingly, the embodiments described herein should not be interpreted as limiting the regions shown herein to specific shapes, but rather as including deviations in shape, for example, as a result of manufacturing. For example, regions shown or described as flat may typically have rough and / or nonlinear features. Furthermore, acute angles shown may be curvilinear. Therefore, the regions shown in the drawings are essentially schematic, and their shapes are not intended to represent the exact shapes of the regions or to limit the scope of the claims of this disclosure.

[0142] While specific embodiments are described, alternatives, modifications, changes, improvements, and substantial equivalents that are not currently anticipated or foreseeable may be conceived by the applicant or other persons skilled in the art. Accordingly, the attached claims, which may be filed and amended, are intended to encompass all such alternatives, modifications, changes, improvements, and substantial equivalents. [Explanation of symbols]

[0143] 10, 10a Thermal Management Sheet 12 Polyurethane foam layer 14, 16 External surface 22. Sodium borate 88 Material Cells 103 and 104 201, 202 Pouch Cells 1002, 1003 Cell Assembly 1004 Multi-cell assembly, battery assembly 910, 920 Aluminum End Plates 930, 940 Heat-insulating film 950 test samples 960 Cell Array 965 Housing 970 Mica Plate Cell Analog 980 Thermocouple Sensor 990 Hot Plate 2001 Battery 5000, 7000 equipment

Claims

1. A method for forming a thermal management sheet for a battery, comprising a cured polyurethane foam, The steps include: forming an uncured polyurethane foam by combining an active hydrogen-containing component containing a polyol and an isocyanate component containing a polyisocyanate; The steps include curing the uncured polyurethane foam to form the cured polyurethane foam, and Includes, The uncured polyurethane foam is, with respect to the total mass of the uncured polyurethane foam, 3 to 68 mass percent or 14 to 36 mass percent sodium borate, 0.1 to 7 mass percent or 2 to 5 mass percent of surfactant, and 0.001 to 9 mass percent, or 0.04 to 9 mass percent, or 0.04 to 7 mass percent, or 3 to 7 mass percent of catalyst Includes, The cured polyurethane foam has a density of 12 to 35 pounds / cubic foot (192 to 561 kilograms / cubic meter) or 15 to 20 pounds / cubic foot (240 to 320 kilograms / cubic meter), A method wherein the cured polyurethane foam has a thickness of 1 to 30 mm, or 1 to 20 mm, or 1 to 15 mm, or 1 to 10 mm, or 1 to 8 mm, or 1.5 to 8 mm, or 1.5 to 6 mm, or 2 to 4 mm.

2. The method according to claim 1, wherein the uncured polyurethane foam further comprises 0 to 33 mass percent, or more than 0 to 33 mass percent, or 7 to 18 mass percent of aluminum hydroxide, based on the total mass of the uncured polyurethane foam.

3. The method according to claim 1 or 2, wherein the uncured polyurethane foam further comprises 0 to 33 mass percent, greater than 0 to 33 mass percent, or 7 to 18 mass percent of zinc borate, based on the total mass of the uncured polyurethane foam.

4. The uncured polyurethane foam is, with respect to the total mass of the uncured polyurethane foam, 0 to 33 mass percent, or greater than 0 to 33 mass percent, or 6 to 18 mass percent of aluminum hydroxide, and 0 to 33 mass percent, or greater than 0 to 33 mass percent, or 6 to 18 mass percent zinc borate The method according to any one of claims 1 to 3, further comprising:

5. The method according to claim 1 or 3, wherein the uncured polyurethane foam contains 0 mass percent of aluminum hydroxide with respect to the total mass of the uncured polyurethane foam.

6. The method according to claim 1 or 2, wherein the uncured polyurethane foam contains 0 mass percent of zinc borate relative to the total mass of the uncured polyurethane foam.

7. The method according to claim 1, wherein the uncured polyurethane foam contains 0% by mass of aluminum hydroxide and 0% by mass of zinc borate, based on the total mass of the uncured polyurethane foam.

8. The step of combining the active hydrogen-containing component and the isocyanate component is performed with respect to the total mass of the composition. 70 to 90 mass percent or 75 to 89 mass percent of the active hydrogen-containing component; and 10 to 30 mass percent or 11 to 25 mass percent of the isocyanate component The method according to any one of claims 1 to 7, comprising combining the two.

9. The method according to any one of claims 1 to 8, wherein the stoichiometric ratio of the isocyanate moiety to the hydroxyl group in the uncured polyurethane foam is 0.85:1 to 1.40:1 or 1.00:1 to 1.20:

1.

10. The method according to any one of claims 1 to 9, further comprising forming the uncured polyurethane foam by a step of foaming, a step of physically foaming, a step of chemically foaming, or a combination thereof.

11. A thermal management sheet for a battery formed by the method described in any one of claims 1 to 10.

12. The thermal management sheet for a battery according to claim 11, wherein the thermal management sheet is made of the cured polyurethane foam.

13. The thermal control sheet according to claim 11 or 12, wherein the cured polyurethane foam has a compressive deflection of 0.2 to 125 pounds / square inch, or 1 to 36 pounds / square inch, or 3 to 30 pounds / square inch, determined according to ASTM D3574, each with a deflection of 25%.

14. The thermal control sheet according to any one of claims 11 to 13, wherein the cured polyurethane foam has a compression set of 0 to 15%, or 0 to 10%, or 0 to 5%, or greater than 0 to 15%, or greater than 0 to 10%, or greater than 0 to 5%, as determined at 70°C according to ASTM D3574-95 Test D.

15. A battery assembly comprising a thermal management sheet according to any one of claims 11 to 14 on the surface of an electrochemical cell.

16. The battery assembly according to claim 15, wherein the assembly comprises at least two electrochemical cells.

17. Battery assembly according to claim 16; and Housing that at least partially encloses the aforementioned battery assembly A battery equipped with this feature.

18. Polyols and, Polyisocyanate and, 3 to 68 mass percent or 14 to 36 mass percent sodium borate, A surfactant in an amount of 0.1 to 7 mass percent or 2 to 5 mass percent, A catalyst in an amount of 0.001 to 9 mass percent, or 0.04 to 9 mass percent, or 0.04 to 7 mass percent, or 3 to 7 mass percent An uncured polyurethane foam composition comprising, The mass percentage is the uncured polyurethane foam composition relative to the total mass of the uncured polyurethane foam composition.

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