Composition

Abstract

The present specification discloses compositions and uses thereof. The composition can form a low-density layer, sheet or film having excellent retardation or prevention properties against heat and flame and having excellent flame retardancy. Such a layer, sheet or film may be referred to as a foamed sheet. The present specification also discloses a composition or a foam sheet. For example, the composition or the foam sheet is applied to a product formed by integrating a plurality of elements, so that the temperature of the product can be uniformly maintained while effectively responding to heat or flame generated by the elements. For example, the composition or the foaming sheet is applied to a product, so that even when abnormal heat, explosion or fire occurs in one of the plurality of elements, the influence of such heat, explosion or fire on other adjacent elements can be prevented or minimized.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0128791, dated September 26, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This specification relates to the compositions and their uses. Background Technology

[0003] The importance of technologies for handling the heat generated by products is increasing, but the handling, maintenance and control of heat in products made using multiple heating elements is a challenge.

[0004] For example, it is crucial to prevent phenomena such as TR (Thermal Runaway) or TP (Thermal Propagation) from occurring in battery modules or battery packs. A battery module or battery pack comprises a plurality of battery cells or battery modules that are relatively positioned adjacent to each other.

[0005] In such a structure, the phenomenon where abnormal heating, fire, and / or explosion occurring in one battery cell and / or module propagates in a chain to other adjacent battery cells is called a TR or TP phenomenon. For stability purposes, it is essential to manage the chain fires or chain explosions caused by such TR or TP phenomena.

[0006] Patent Document 1 discloses an organosilicon pad applicable to delaying thermal runaway in batteries. Patent Document 1 ensures the effect of delaying thermal diffusion by adding aluminum hydroxide or magnesium hydroxide to the organosilicon pad.

[0007] However, the flame-retardant effect of such known silicone pads is insufficient. Furthermore, the silicone pad disclosed in Patent Document 1 has a relatively high specific gravity, making it unsuitable for applications requiring weight reduction.

[0008] <Prior art documents>

[0009] <Patent Documents>

[0010] (Patent Document 1) Korean Patent No. 10-2425374 Summary of the Invention

[0011] Technical issues

[0012] This specification relates to compositions and their uses. The compositions are foamable compositions that can be foamed to form porous sheets (foam sheets). This specification aims to disclose that foam sheets are lightweight while possessing excellent heat absorption properties, heat and flame barrier properties, and flame retardant properties.

[0013] The compositions or foam sheets disclosed herein can be effectively used in a variety of products that require heat or flame management. For example, applying the compositions or foam sheets to products formed by integrating multiple components can effectively prevent the spread of flames to other adjacent components due to abnormal heating or explosion in one of the components, while uniformly maintaining the temperature of the product.

[0014] Technical solution

[0015] Unless otherwise stated, the physical properties mentioned herein that are affected by temperature are those measured at room temperature.

[0016] The term room temperature refers to the natural temperature without artificial heating or cooling, and means any temperature in the range of approximately 10°C to 30°C, such as approximately 23°C or approximately 25°C.

[0017] Unless otherwise stated, the unit of temperature in this specification is °C.

[0018] Unless otherwise stated, the physical properties mentioned herein that are affected by pressure are those measured at atmospheric pressure. The term atmospheric pressure is the natural pressure without artificial pressurization or depressurization, which is usually referred to as approximately one atmosphere (approximately 700 to 800 mmHg).

[0019] Unless otherwise stated, the physical properties mentioned herein that are affected by humidity are those measured at room temperature and normal pressure under conditions of humidity without human intervention.

[0020] This specification relates to compositions. The term composition means a mixture of two or more components. A composition can be a foamable composition. The term foamable composition means a composition capable of forming a foamed sheet through a foaming process. The foamed sheet is a porous sheet, membrane, or layer containing one or more pores.

[0021] The foamable composition may contain at least a polyorganosiloxane component and an inorganic hydrate. The term "polyorganosiloxane component" refers to a component consisting of one, two, or more polyorganosiloxanes. That is, the polyorganosiloxane component contains only polyorganosiloxanes.

[0022] As is well known, polyorganosiloxanes refer to polymer compounds formed by a silicon-oxygen backbone (siloxane bonds). Such polyorganosiloxanes contain at least one of four types of siloxane units (M units, D units, T units, and Q units), said siloxane units being derived from the formula (R3SiO2). 1 / 2 ) siloxane units (often also called M units), formula (R2SiO) 2 / 2) siloxane units (often also called D units), formula (RSiO) 3 / 2 ) siloxane units (often also called T units) and formula (SiO) 4 / 2 It is composed of siloxane units (often also called Q units). The R present in the M, D and T units is a functional group bonded to silicon, examples of which include hydrogen, hydroxyl, monovalent hydrocarbon (e.g. alkyl, haloalkyl, alkenyl, aryl and / or aralkyl, etc.) and alkoxy, etc.

[0023] The alkyl, haloalkyl, and alkoxy groups can each have 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, respectively. The alkyl, haloalkyl, and alkoxy groups can be linear, branched, or cyclic, and can be substituted with one or more substituents if desired.

[0024] The aryl group can be an aryl group having 6 to 30 carbon atoms, 6 to 24 carbon atoms, 6 to 18 carbon atoms, or 6 to 12 carbon atoms, and examples of such aryl groups include, but are not limited to, phenyl, tolyl, xylyl, or naphthyl groups.

[0025] Aryl groups can be aryl groups having 7 to 35 carbon atoms, 7 to 29 carbon atoms, 7 to 23 carbon atoms, or 7 to 17 carbon atoms; and examples include, but are not limited to, benzyl or phenethyl.

[0026] The specific types of alkenes are described below.

[0027] To give the composition suitable foaming properties and effectively form the desired foamed sheet, the polyorganosiloxane component can be modified. For example, the polyorganosiloxane component may contain at least a siloxane unit with hydrogen bonded to silicon (silicon-bonded hydrogen), a siloxane unit with hydroxyl bonded to silicon (silicon-bonded hydroxyl), and a siloxane unit with alkenyl bonded to silicon (silicon-bonded alkenyl), or may contain a polyorganosiloxane having said siloxane units. When said units are included in a polyorganosiloxane, a single polyorganosiloxane molecule may also contain all said siloxane units, or two or more types of polyorganosiloxanes containing at least one of said siloxane units may be mixed to form the polyorganosiloxane component.

[0028] The alkenyl group can be an alkenyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, such as vinyl or allyl. The alkenyl group can be linear, branched, or cyclic, and can be substituted with one or more substituents if desired.

[0029] If a polyorganosiloxane component is applied to the foaming process described below, a reaction occurs in which hydroxyl groups bonded to silicon atoms react with hydrogen atoms bonded to silicon atoms to form so-called siloxane bonds (first reaction); and a so-called addition reaction (hydrosilanization) occurs between hydrogen atoms bonded to silicon atoms and alkenyl groups bonded to silicon atoms (second reaction). During the first reaction, hydrogen gas (H2) is generated, and this hydrogen gas acts as a blowing agent while pores are formed within the polymer or cross-linked network formed by the first and second reactions, thereby producing a foamed sheet. The desired foamed sheet can be obtained by initiating a reaction with such a mechanism in the presence of a specific inorganic hydrate.

[0030] To achieve this effect, the composition of the polyorganosiloxane component can be adjusted.

[0031] For example, the polyorganosiloxane contained in the polyorganosiloxane component may be present such that the OH / H ratio of Formula 1 is within a predetermined range.

[0032] [Formula 1]

[0033] OH / H

[0034] In Formula 1, H is the total number of moles of silicon-bonded hydrogen contained in the polyorganosiloxane component, and OH is the total number of moles of silicon-bonded hydroxyl groups contained in the polyorganosiloxane component.

[0035] The lower limit of OH / H in Formula 1 above can be approximately 0.01, 0.03, 0.05, 0.07, 0.09, 0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, or 1.07, and its upper limit can be approximately 10, 9, 8, 7, 6, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.8, or 0.6. OH / H can be greater than or equal to, or greater than any of the lower limits listed above; less than or equal to, or less than any of the upper limits listed above; or less than or equal to, or less than any of the upper limits listed above, while simultaneously being greater than or equal to, or greater than any of the lower limits listed above.

[0036] For example, the polyorganosiloxane contained in the polyorganosiloxane component may be present such that the H / V in Formula 2 is within a predetermined range.

[0037] [Equation 2]

[0038] H / V

[0039] In Equation 2, H represents the total number of moles of silicon-bonded hydrogen contained in the polyorganosiloxane component, and V represents the total number of moles of silicon-bonded alkenyl groups contained in the polyorganosiloxane component.

[0040] The lower limit of H / V in Equation 2 above can be approximately 50, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 150, 200, 220, 240, 260, 280 or 285, and its upper limit can be approximately 600, 550, 500, 450, 400, 380, 360, 340, 320, 300, 290, 280, 260, 240, 220, 200, 195, 190, 185, 180, 175, 170, 165, 160, 155, 150, 145 or 140. H / V can be greater than or equal to, or greater than any of the lower limits selected above; less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0041] For example, the polyorganosiloxane contained in the polyorganosiloxane component may be present such that OH / (H+V) in Formula 3 is within a predetermined range.

[0042] [Formula 3]

[0043] OH / (H+V)

[0044] In Formula 3, H is the total number of moles of silicon-bonded hydrogen contained in the polyorganosiloxane component, OH is the total number of moles of silicon-bonded hydroxyl groups contained in the polyorganosiloxane component, and V is the total number of moles of silicon-bonded alkenyl groups contained in the polyorganosiloxane component.

[0045] The lower limit of OH / (V+H) in Equation 3 can be approximately 0.01, 0.05, 0.1, 0.3, 0.4, 0.45, 0.5, 0.7, 0.9, 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, or 1.07, and its upper limit can be approximately 10, 9, 8, 7, 6, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.8, or 0.6. OH / (V+H) can be greater than or equal to, or greater than any of the lower limits listed above; less than or equal to, or less than any of the upper limits listed above; or less than or equal to, or less than any of the upper limits listed above, while being greater than or equal to, or greater than any of the lower limits listed above.

[0046] By configuring the polyorganosiloxane component such that OH / H, H / V, and OH / (V+H) of formulas 1 to 3 above are within predetermined ranges, a first reaction can be carried out during the foaming process to form polymer chains and generate foaming gas (H2), and a second reaction can be carried out to crosslink the material to form a desired foamed sheet. The desired foamed sheet can be obtained by initiating such a process in the presence of a specific inorganic hydrate.

[0047] The amount of silicon-bonded hydroxyl groups in the polyorganosiloxane component can be controlled. For example, the lower limit of the amount of hydroxyl groups in the polyorganosiloxane component can be approximately 0.01 mmol / g, 0.05 mmol / g, 0.1 mmol / g, 0.5 mmol / g, 1 mmol / g, 1.1 mmol / g, 1.11 mmol / g, 1.12 mmol / g, 1.13 mmol / g, 1.14 mmol / g, or 1.15 mmol / g, and the upper limit can be approximately 5 mmol / g, 4.5 mmol / g, 4 mmol / g, 3.5 mmol / g, 3 mmol / g, 2.5 mmol / g, 2 mmol / g, 1.9 mmol / g, 1.8 mmol / g, 1.7 mmol / g, 1.6 mmol / g, 1.5 mmol / g, 1.4 mmol / g, 1.3 mmol / g, or 1.2 mmol / g. The content of hydroxyl groups may be greater than or equal to, or greater than any of the lower limits selected above; less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0048] There are no particular limitations on the specific types of polyorganosiloxanes suitable for forming polyorganosiloxane components. For example, after obtaining appropriate types of polyorganosiloxanes from polyorganosiloxane suppliers in the industry, polyorganosiloxane components can be prepared by mixing them such that the OH / H, H / V, and OH / (V+H) ratios of Formulas 1 to 3 above have ratios within the aforementioned ranges.

[0049] The lower limit of the content of the polyorganosiloxane component in the composition can be approximately 30%, 35%, 40%, 45%, 50%, 52%, 54%, 55%, 58%, or 60% by weight, and the upper limit can be approximately 90%, 85%, 80%, 75%, 70%, 65%, or 60% by weight. This content can be greater than or equal to, or greater than, any of the lower limits selected above; less than or equal to, or less than, any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than, any of the lower limits selected above. The content is based on the content of the solid contents of the composition. For example, when the foamable composition contains a solvent, the content is based on the ratio of the total amount of components other than the solvent in the foamable composition.

[0050] In addition to the polyorganosiloxane component, the foamable composition may also contain inorganic hydrates. These inorganic hydrates may have endothermic properties, thus imparting heat control or flame control properties to the foam sheet.

[0051] The desired foamed sheet can be obtained by applying an inorganic hydrate containing water of crystallization in a specific proportion and having a crystal morphology capable of retaining the water of crystallization, and by reacting and foaming the polyorganosiloxane component in the presence of the inorganic hydrate.

[0052] Such inorganic hydrates can be represented, for example, by the following chemical formula 1:

[0053] [Chemical Formula 1]

[0054]

[0055] In chemical formula 1, M is a metal cation, X is an anion, and r, s, and n are each arbitrary numbers.

[0056] In chemical formula 1, M is a metal cation. M can be one metal or two or more metals. M is, for example, a cation of a metal belonging to Groups 1 to 13 of the periodic table, and can be a metal cation formed from one or two or more metals selected from those belonging to Groups 1 to 13. For example, M can be a metal cation formed from one or two or more metals selected from those belonging to Groups 1, 2, 12, and 13 of the periodic table.

[0057] The metals that form M can be metals that belong to the aforementioned groups of the periodic table and also to periods 2 through 6 of the periodic table. For example, M can be a cation of one or more metals that belong to the aforementioned groups of the periodic table and also to periods 2 through 6, periods 2 through 4, or periods 2 through 3 of the periodic table.

[0058] Examples of metals may be selected from one or more of Li, K, Al, Mn, Ca, Na, Zn, Fe, Ba, Mg and Sr, but are not limited thereto.

[0059] The type of metal ion can be selected to exhibit the crystallinity required to form the desired foam sheet and retain the water of crystallization.

[0060] For example, M in the above chemical formula 1 may be selected from one or more of alkali metal ions, alkaline earth metal ions, post-transition metal ions, and metalloid ions, and more preferably from two or more of the aforementioned. Particularly preferably, M in the above chemical formula 1 may simultaneously contain alkali metal ions and post-transition metal ions.

[0061] Alkali metals can be exemplified as Li, Na, K, Rb, Cs and / or Fr, alkaline earth metals can be exemplified as Be, Mg, Ca, Sr, Ba and / or Ra, late transition metals can be exemplified as Al, Ga, In and / or Tl, and metalloids can be exemplified as B, Si, Ge, As, Sb and / or Te, but are not limited thereto.

[0062] As M, a cation of a metal belonging to one or more of the periods selected from the second, third, and fourth periods of the periodic table can be used.

[0063] In chemical formula 1, X is an anion, and there are no particular restrictions on its specific type. For example, X can be selected from halide anions (e.g., F). - Cl - , and / or Br - wait), OH - , , , , and One or more of them, but not limited to this.

[0064] In chemical formula 1, r and s are numbers determined according to the types of metal cations and anions.

[0065] For example, r and s can be conditions that satisfy the equation The number of ions. Here, p is the oxidation number (charge number) of the metal cation. For example, when two or more metal ions are used as M, p is the sum of the values ​​obtained by multiplying the oxidation number (charge number) of each metal ion by the molar number of the relevant metal ion. Here, q is the oxidation number (charge number) of the anion. For example, when two or more anions are used as X, q is the sum of the values ​​obtained by multiplying the oxidation number (charge number) of each anion by the molar number of the relevant anion.

[0066] There are no particular restrictions on the specific ranges of r and s, as long as they are chosen to satisfy the equation. For example, r is a number in the range of 1 to 3, which can be, for example, 1, 2 or 3, and s is a number in the range of 1 to 3, which can be, for example, 1, 2 or 3.

[0067] In chemical formula 1, n represents the number of moles of water molecules (water of crystallization) present in the hydrate, with a lower limit of approximately 8, 9, 10, 11, or 12, and an upper limit of approximately 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, or 8. n can be greater than or equal to, or greater than, any lower limit selected from the list above; or less than or equal to, or less than, any upper limit selected from the list above, while being greater than or equal to, or greater than, any lower limit selected from the list above.

[0068] The amount of water of crystallization contained in a hydrate is affected by the hydrate's crystal structure. Hydrates having a crystal structure in which n falls within the aforementioned range contribute to the formation of the desired foam sheet.

[0069] Inorganic hydrates can have particle sizes at appropriate levels. By adjusting the particle size, the viscosity of the foamable composition can be adjusted, and appropriate foaming efficiency can be ensured.

[0070] For example, the lower limit of the so-called D50 particle size of inorganic hydrates can be around 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or 10 μm, and its upper limit can be around 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 95 μm, 90 μm, 85 μm, 80 μm, 75 μm, 70 μm, 65 μm, 60 μm, 55 μm, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 25 μm, 30 ... The D50 particle size is approximately 10 μm, 20 μm, 15 μm, or 10 μm. This D50 particle size can be greater than or equal to, or greater than any of the lower limits selected above; less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above. The D50 particle size is the average particle size measured in the manner described in section "2. Average Particle Size" of the Examples section of this specification.

[0071] The content of inorganic hydrates can be adjusted according to the purpose. For example, based on 100 parts by weight of the polyorganosiloxane component, the lower limit of the content of inorganic hydrates can be approximately 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, or 15 parts by weight, and the upper limit can be approximately 30 parts by weight, 28 parts by weight, 26 parts by weight, 24 parts by weight, 22 parts by weight, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight, or 3 parts by weight. The content may be greater than or equal to, or greater than any of the lower limits selected above; less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0072] The foamable composition may also contain flame retardants, such as flame retardant particles. The application of flame retardant particles ensures flame retardancy.

[0073] Inorganic flame retardants can be used as flame retardants, and for example, one or more of the following can be used, but not limited to: metal hydroxides (e.g., aluminum hydroxide or magnesium hydroxide), antimony oxides (trioxide, tetroxide), zinc stannate, phosphorus products, guanidine, molybdates and zirconium.

[0074] The size of the flame retardant can be controlled to give the foam sheet appropriate flame retardancy, processability during the foaming process, etc.

[0075] For example, the lower limit of the D50 particle size of a flame retardant can be approximately 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, or 25 μm, and its upper limit can be approximately 150 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, or 30 μm. The D50 particle size can be greater than or equal to, or greater than any of the lower limits listed above; less than or equal to, or less than any of the upper limits listed above; or less than or equal to, or less than any of the upper limits listed above, while being greater than or equal to, or greater than any of the lower limits listed above. Here, the D50 particle size is the average particle size measured in the manner described in section "2. Average Particle Size" of the Examples section of this specification.

[0076] In the foamable composition, based on 100 parts by weight of the polyorganosiloxane component, the lower limit of the flame retardant content can be approximately 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, or 60 parts by weight, and the upper limit can be approximately 500 parts by weight, 450 parts by weight, 400 parts by weight, 350 parts by weight, 300 parts by weight, 250 parts by weight, 200 parts by weight, 150 parts by weight, 100 parts by weight, 90 parts by weight, 80 parts by weight, 70 parts by weight, or 60 parts by weight. The ratio can be greater than or equal to, or greater than any of the lower limits selected above; less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0077] In view of other functionalities such as viscosity adjustment, foamable compositions may contain inorganic particles that are different from inorganic hydrates and flame retardants as described above, and may contain, for example, silica.

[0078] As inorganic particles, particles of appropriate size can be used depending on the intended purpose. For example, the lower limit of the D50 particle size of inorganic particles can be approximately 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm, and its upper limit can be approximately 1,000 nm, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, or 55 nm. The D50 particle size can be greater than or equal to, or greater than any of the lower limits listed above; less than or equal to, or less than any of the upper limits listed above; or less than or equal to, or less than any of the upper limits listed above, while being greater than or equal to, or greater than any of the lower limits listed above. Here, D50 particle size is the average particle size measured in the manner described in the "2. Average Particle Size" section of the Examples section of this specification.

[0079] In the foamable composition, based on 100 parts by weight of the polyorganosiloxane component, the lower limit of the weight ratio of inorganic particles can be approximately 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, or 2.5 parts by weight, and the upper limit can be approximately 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, 25 parts by weight, 20 parts by weight, 15 parts by weight, 10 parts by weight, 9 parts by weight, 8 parts by weight, 7 parts by weight, 6 parts by weight, 5 parts by weight, 4 parts by weight, or 3 parts by weight. This ratio can be greater than or equal to, or greater than, any lower limit selected from the lower limits listed above; less than or equal to, or less than, any upper limit selected from the upper limits listed above; or less than or equal to, or less than, any upper limit selected from the upper limits listed above, while simultaneously greater than or equal to, or greater than, any lower limit selected from the lower limits listed above.

[0080] In addition to the components described above, the expandable composition may also contain any necessary additives. For example, the expandable composition may contain a catalyst for promoting the first and / or second reactions of the polyorganosiloxane component. For example, a so-called addition reaction catalyst may be used as the catalyst for the second reaction, and representative examples include platinum-based catalysts, but the types of catalysts that may be included in the expandable composition are not limited to those described above. When a catalyst is applied, there is no limit to its content, and it may be used in catalytic amounts based on known information.

[0081] In addition to catalysts, foamable compositions may also contain appropriate additives.

[0082] In one example, the composition may substantially not contain any substance known as a so-called blowing agent for forming the desired foamed sheet. That is, the desired foamed sheet can be formed by foaming and curing the foamed sheet in the presence of inorganic hydrates via hydrogen generated from the reaction of the aforementioned polyorganosiloxane component, without substantially any blowing agent present. For example, based on the total weight of the composition, the upper limit of the blowing agent content may be about 10 wt%, 8 wt%, 6 wt%, 4 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, 0.005 wt%, 0.001 wt%, 0.0005 wt%, or about 0.0001 wt%, and the lower limit may be about 0 wt%. When the composition substantially does not contain a blowing agent, the blowing agent content may be less than or equal to, or less than, any of the upper limits selected above; or less than or equal to, or less than, any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above. The content is based on the amount of solid contents in the composition. For example, when the foamable composition contains a solvent, the content is based on the ratio of the total amount of components in the foamable composition other than the solvent.

[0083] The types of blowing agents include well-known components in the industry that are capable of foaming polyorganosiloxane components. When such components are included in the composition in a form or amount capable of foaming the polyorganosiloxane component, the composition can be evaluated as containing a blowing agent.

[0084] The viscosity of the foamable composition can be adjusted by considering the processability during the foaming process, as described below. For example, the lower limit of the viscosity of the foamable composition can be around 30,000 cps, 35,000 cps, 40,000 cps, 45,000 cps, 50,000 cps, 55,000 cps, 60,000 cps, 65,000 cps, 70,000 cps, 75,000 cps, 80,000 cps, 85,000 cps, 90,000 cps, or 95,000 cps, and its upper limit can be around 1,000,000 cps, 900,000 cps, 800,000 cps, 700,000 cps, 600,000 cps, 500,000 cps, 400,000 cps, or 300,000 cps. The viscosity is approximately 200,000 cps, 100,000 cps, 90,000 cps, 80,000 cps, 70,000 cps, 60,000 cps, or 50,000 cps. The viscosity can be greater than or equal to, or greater than, any of the lower limits selected above; or less than or equal to, or less than, any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above. The viscosity was measured according to the "1. Viscosity Measurement" section of the Examples section of this specification, and is the viscosity under conditions of 25°C and a shear rate of 1 / second.

[0085] This specification also discloses foam sheets. A foam sheet is a layer, film, or sheet containing one or more pores.

[0086] Such foam sheets can contain polyorganosiloxane alkyl groups and inorganic hydrates dispersed in the matrix.

[0087] Polyorganosiloxanes can serve as adhesives to maintain the shape of foam sheets and can be in the form of porous films, sheets, or layers. Such polyorganosiloxanes may contain one or more pores.

[0088] Foam sheets may also contain inorganic hydrates dispersed in polyorganosiloxane alkyl bodies.

[0089] Foamed sheets can be formed by foaming and curing the above-described foamable composition in a manner to be described below. Therefore, the polyorganosiloxane body may contain the above-described polyorganosiloxane component, or it may contain its reactants. For example, the polyorganosiloxane body may be the above-described polyorganosiloxane component, or it may be its reactants.

[0090] Furthermore, the inorganic hydrate can also be the inorganic hydrate contained in the above-described foamable composition, the specific type, size, and content of which are as described above. Regarding the content, the content in the foamable composition can be equivalently applied by replacing the polyorganosiloxane component serving as the basis for the weight ratio with a polyorganosiloxane body. Such inorganic hydrates can also be contained in the foamed sheet in a state in which they remain in their pre-foaming form, or in a state in which they have lost some of their water of crystallization.

[0091] The flame retardants and inorganic particles (such as silica) described previously may also be included in the foamed sheet. The specific types, sizes, and contents of the flame retardants and inorganic particles are as described above, and regarding the contents, the contents in the foamable composition can be equivalently applied by replacing the polyorganosiloxane component, which serves as the basis for the weight ratio, with a polyorganosiloxane body.

[0092] Such foam sheets can exhibit excellent flame retardancy. Typically, it is not easy to ensure both heat absorption properties and flame retardancy for foam sheets; however, according to the disclosure in this specification, foam sheets with excellent flame retardancy and heat absorption properties obtained through inorganic hydrates can be provided. In particular, the aforementioned flame retardancy can be ensured even when the foam sheet maintains a low density or specific gravity.

[0093] For example, according to the UL 94 vertical burning test standard, the flame retardancy rating of the foam sheet can be V1 or V0. Such a flame retardancy rating can be evaluated in the manner described in section "3. Flame Retardancy" of the Examples section of this specification.

[0094] Foam sheets can have low density characteristics. For example, the upper limit of the density of foam sheets can be 0.5 g / cm³. 3 0.45g / cm 3 0.4 g / cm 3 0.35 g / cm 3 Or 0.3 g / cm 3 The range is approximately [value missing], and its lower limit can be 0.1 g / cm³. 3 0.15 g / cm 3 0.2 g / cm 3 Or 0.25 g / cm 3 The density can be less than or equal to, or less than any of the upper limits selected above; or it can be less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0095] Foamed sheets can be formed by foaming the above-described foamable composition. Therefore, foamed sheets can be foamed products of the foamable composition, or can contain foamed products thereof.

[0096] The thickness of the foam sheet can be adjusted to suit various purposes. For example, the lower limit of the foam sheet thickness can be approximately 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm, and its upper limit can be approximately 100 mm, 95 mm, 90 mm, 85 mm, 80 mm, 75 mm, 70 mm, 65 mm, 60 mm, 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, or 5 mm. This thickness can be greater than or equal to, or greater than, any of the lower limits listed above; less than or equal to, or less than, any of the upper limits listed above; or less than or equal to, or less than, any of the upper limits listed above, while being greater than or equal to, or greater than, any of the lower limits listed above.

[0097] There are no particular limitations on the method used to produce foamed sheets by foaming the above-described foamable composition. For example, foaming can be performed by forming the foamable composition into a desired shape (e.g., by coating or the like to form it in the form of a layer) and applying heat to the foamable composition. In this case, the foamed sheet can be formed simultaneously by the generation of foaming gas (H2) through the first reaction and by the curing process through the first and second reactions.

[0098] The lower limit of the temperature for the foaming process can be, for example, around 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C, and the upper limit can be around 300°C, 250°C, 200°C, 150°C, 100°C, 95°C, 90°C, 85°C, or 80°C. The foaming process can be carried out by maintaining the foamable composition at a temperature greater than or equal to, or greater than, any of the lower limits listed above; a temperature less than or equal to, or less than, any of the upper limits listed above; or a temperature less than or equal to, or less than, any of the upper limits listed above, while simultaneously greater than or equal to, or greater than, any of the lower limits listed above.

[0099] The time used for the foaming process can be adjusted by considering factors such as the desired foaming scale-up ratio. Generally, the longer the foaming process, the greater the foaming scale-up ratio is likely to be. The foaming scale-up ratio is the ratio of the volume of the foamable composition after the foaming process to the volume of the foamable composition before the foaming process (or the thickness ratio for the same area). The lower limit of the foaming scale-up ratio can be, for example, approximately 1.2 times, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, or 6 times, and its upper limit can be approximately 30 times, 25 times, 20 times, 15 times, 10 times, 9 times, 8 times, 7 times, 6 times, 5 times, or 4 times. The foaming scale-up ratio can be greater than or equal to, or greater than any of the lower limits selected above; or less than or equal to, or less than any of the upper limits selected above; or less than or equal to, or less than any of the upper limits selected above, while being greater than or equal to, or greater than any of the lower limits selected above.

[0100] This specification also discloses products (heat-generating products) comprising foamable compositions or foam sheets. The compositions or foam sheets can be usefully used as materials for controlling the heat of heating components, heating elements, or heating products. Therefore, products may include heating components, heating elements, or heating products. Heating components, heating elements, or heating products refer to components, elements, or products that generate heat during use, and their types are not particularly limited. Representative heating components, heating elements, or heating products include various electrical / electronic products, including battery cells, battery modules, or battery packs.

[0101] The composition or foam sheet is particularly applicable to products formed by integrating multiple heating components, heating elements or heating products, such that when abnormal heating or explosion occurs in any of the multiple heating components, heating elements or heating products, it can be effectively used to suppress or prevent the heat generated by heating and the flame generated by explosion from spreading to other adjacent heating components, heating elements or heating products, and thus causing chain heating or explosion.

[0102] For example, products that utilize the composition or foam sheet can be battery modules.

[0103] Therefore, this specification discloses a battery module comprising a foamed sheet or a foamable composition. Such a battery module includes a plurality of battery cells, wherein the foamed sheet or foamable composition may be present among at least some of the plurality of battery cells.

[0104] If a composition or foam sheet is used, there are no particular restrictions on the specific configuration of the battery module, such as the type or arrangement of the battery cells, and any known type or method can be applied.

[0105] Beneficial effects

[0106] This specification discloses compositions and their uses. These compositions can form low-density layers, sheets, or films that exhibit excellent delay or prevention properties against heat and flame and possess excellent flame retardancy. Such layers, sheets, or films may be referred to as foam sheets. This specification also discloses compositions or foam sheets. For example, applying the composition or foam sheet to a product formed by integrating multiple components can, in turn, maintain the product temperature uniformly while effectively responding to heat or flame generated by the components. For example, applying the composition or foam sheet to a product can, even if abnormal heating, explosion, or fire occurs in one of the multiple components, prevent or minimize the impact of such heating, explosion, or fire on other adjacent components. Detailed Implementation

[0107] In the following, foamable compositions and the like will be described in detail by way of examples and comparative examples, but the scope of foamable compositions and the like is not limited to the following.

[0108] 1. Viscosity Measurement

[0109] Viscosity was measured using a viscometer (Brookfield, Brookfield DV2) and a CPA-52Z rotor. The rotor was selected based on the viscosity range to be measured. After zeroing the viscometer, the rotor was mounted to the rotor connector, and the plate to the plate connector. The adjusting lever was then adjusted to create a constant separation space (gap) between the rotor and the plate. The plates were separated, and 0.5 mL of sample was applied to the center of the separated plates. The plate coated with the curable composition was then mounted to the plate connector, and the viscosity was measured at approximately 25°C after waiting until the torque value reached zero. The viscosity was measured while the rotor was rotating, taking shear rate into account, and at a shear rate of 1 / second. The viscosity was stabilized by maintaining the determined rotation speed for approximately 1 minute before measurement.

[0110] 2. Average particle size

[0111] The average particle size was measured using a Marvern MASTERSIZER 3000 instrument according to ISO-13320 standards. Distilled water was used as the solvent. The particle size can be obtained by irradiating the particles dispersed in the solvent with a laser using the instrument and analyzing the intensity and directionality of the laser light scattered and / or reflected by the particles using Mie theory. The average particle size can be obtained by analyzing the diameter of spheres with the same volume as the dispersed filler to obtain the volume-based particle size distribution, and thus obtaining the D50 particle size (the particle size at 50% of the cumulative volume) as the median of the distribution.

[0112] 3. Flame retardancy

[0113] Flame retardancy was determined according to the vertical burning test of UL 94 standard. The flame retardancy was evaluated using specimens, each of which consisted of a foam sheet produced in the examples or comparative examples, cut into bars approximately 1.4 mm thick, 13 mm horizontally, and 125 mm vertically. Flame retardancy was assessed by preparing three specimens for each identical foam sheet and evaluating these specimens.

[0114] According to the UL 94 vertical burning test standard, the burning time (t1) of the rod-shaped specimen is measured and the burning pattern is recorded while one end of the specimen is in contact with a flame at a height of 20 mm for approximately 10 seconds. Subsequently, while the specimen is in contact with the flame again for 10 seconds, the burning time (t2) and afterglow time (t3) are measured and the burning pattern is recorded. For three specimens made using the same foam sheet, t1, t2, and t3 are obtained respectively, and the average of the three obtained values ​​is used as the final t1, t2, and t3 values. In the UL 94 vertical burning test standard, the flame retardancy rating is evaluated according to the following criteria based on times t1, t2, and t3, and in this specification, the flame retardancy rating is also evaluated according to the criteria in Table 1 below.

[0115] [Table 1]

[0116]

[0117] 4. Density Measurement

[0118] The density of the foam sheet was measured using a measuring device (Alfa Mirage MD-300S).

[0119] Example 1.

[0120] Polyorganosiloxane components were prepared by mixing a first polyorganosiloxane (S1) having silicon-bonded hydroxyl groups, a second polyorganosiloxane (S2) having silicon-bonded hydroxyl groups, a third polyorganosiloxane (S3) having silicon-bonded hydroxyl groups, a fourth polyorganosiloxane (S4) having silicon-bonded vinyl groups, a fifth polyorganosiloxane (S5) having silicon-bonded vinyl groups, and a sixth polyorganosiloxane (S6) having silicon-bonded hydrogen groups in a weight ratio of 19:21.5:19:8.5:23.5:8.5 (S1:S2:S3:S4:S5:S6).

[0121] Materials having the equivalents and viscosities shown in Table 1 below as the first, third, fifth, and sixth polyorganosiloxanes are obtained and used from HRS Silicone, and materials having the equivalents and viscosities shown in Table 1 below as the second and fourth polyorganosiloxanes are obtained and used from Gelest Inc.

[0122] Mix for 2 minutes at 750 rpm using a planetary mixer (Thinky Mixer). The equivalence ratios and viscosities of the six polysiloxanes are shown in Table 2 below. The equivalence ratios in Table 2 are information provided by the manufacturer, where, in the case of polysiloxanes with silicon-bonded hydroxyl groups, it is the number of moles of hydroxyl groups per g of polysiloxane; in the case of polysiloxanes with silicon-bonded vinyl groups, it is the number of moles of vinyl groups per g of polysiloxane; and in the case of polysiloxanes with silicon-bonded hydrogen groups, it is the number of moles of hydrogen per g of polysiloxane.

[0123] [Table 2]

[0124]

[0125] When calculating based on the equivalent weight and mixing weight ratio of the polyorganosiloxane component formed by the formulation, the OH / H ratio of Formula 1 is approximately 0.52, the H / V ratio of Formula 2 is approximately 288, the OH / (V+H) ratio of Formula 3 is approximately 0.52, and the content of silicon-bonded hydroxyl groups in the polyorganosiloxane component is approximately 1.15 mmol / g.

[0126] [Formula 1]

[0127] OH / H

[0128] [Equation 2]

[0129] H / V

[0130] [Formula 3]

[0131] OH / (H+V)

[0132] In formulas 1 to 3, H is the total number of moles of hydrogen contained in the prepared polyorganosiloxane component, OH is the total number of moles of hydroxyl groups contained in the prepared polyorganosiloxane component, and V is the total number of moles of alkenyl groups contained in the prepared polyorganosiloxane component.

[0133] Subsequently, the polyorganosiloxane component was mixed with inorganic hydrate, silica, and flame-retardant particles. The mixing was carried out so that the weight ratio (A:B:C:D) of the polyorganosiloxane component (A), flame-retardant particles (B), silica (C), and inorganic hydrate (D) was approximately 100:60:2.5:15.

[0134] Using D50 particles with a diameter of approximately 10 μm As inorganic hydrate (IH), silica (Evonik, Aerosil R972) with a D50 particle size of about 50 nm was used as silica, and aluminum hydroxide (Chalco, H-WF-25SP) with a D50 particle size of about 25 μm was used as flame retardant particles.

[0135] Mix for 2 minutes at 750 rpm using a planetary mixer (Thinky Mixer).

[0136] The obtained composition (foamable composition) has a viscosity of about 98,000 cps at room temperature (about 25°C) and a shear rate of 1 / second.

[0137] The catalyst (DY Silicone PTC-350-1) was further introduced into the foamable composition at a ratio of 0.05 parts by weight relative to 100 parts by weight of the polyorganosiloxane component, and the mixture was mixed for 1 minute at 750 rpm using a planetary mixer (Thinky Mixer).

[0138] A foamable composition with added catalyst is coated onto a release layer of a release-treated PET (poly(ethylene terephthalate)) film to a thickness of approximately 0.8 mm. Another release layer of a release-treated PET (poly(ethylene terephthalate)) film is laminated onto the coated foamable composition layer. The mixture is then cured and foamed in a hot air oven at approximately 80°C to produce a foam sheet with a thickness of approximately 5.0 mm.

[0139] Example 2.

[0140] The foamed sheet was produced in the same manner as in Example 1, except that the foamable composition was prepared such that the weight ratio of the polyorganosiloxane component (S), flame retardant particles (A), silica particles (B), platinum catalyst (C), and inorganic hydrate (D) was 100:60:2.5:0.05:10 (S:A:B:C:D).

[0141] The foamable composition has a viscosity of approximately 76,000 cps at 25°C and a shear rate of 1 / second.

[0142] Example 3.

[0143] The foamed sheet was produced in the same manner as in Example 1, except that the weight ratio of the polyorganosiloxane component (S), flame retardant particles (A), silica particles (B), platinum catalyst (C), and inorganic hydrate (D) was 100:60:2.5:0.05:5 (S:A:B:C:D).

[0144] The viscosity of the foamable composition used is approximately 52,000 cps at 25°C and a shear rate of 1 / second.

[0145] Example 4.

[0146] The foamed sheet was produced in the same manner as in Example 1, except that the weight ratio of the polyorganosiloxane component (S), flame-retardant particles (A), silica particles (B), platinum catalyst (C), and inorganic hydrate (D) in the foamable composition was 100:60:2.5:0.05:2.5 (S:A:B:C:D). The viscosity of the applied foamable composition at 25°C and a shear rate of 1 / second was approximately 43,000 cps.

[0147] Example 5.

[0148] The foam sheet was produced in the same manner as in Example 1, except that the thickness of the foam sheet was 2.8 mm due to the control of curing and foaming time.

[0149] Example 6.

[0150] A foamed sheet with a thickness of about 2.8 mm was produced in the same manner as in Example 5, except that the foamable composition of Example 2 was used.

[0151] Example 7.

[0152] A foamed sheet with a thickness of about 2.8 mm was produced in the same manner as in Example 5, except that the foamable composition of Example 3 was used.

[0153] Example 8.

[0154] A foamed sheet with a thickness of about 2.8 mm was produced in the same manner as in Example 5, except that the foamable composition of Example 4 was used.

[0155] Comparative Example 1.

[0156] The foamed sheet was prepared in the same manner as in Example 1, except that inorganic hydrates were not used. The viscosity of the foamable composition used was approximately 39,000 cps at 25°C and a shear rate of 1 / sec.

[0157] Compare Example 2.

[0158] The foamable composition was prepared and foam sheets were produced in the same manner as in Example 1, except that the foamable composition was prepared using... replace As an inorganic hydrate.

[0159] Comparative Example 3.

[0160] The foamable composition was prepared in the same manner as in Example 1, except that it used replace As an inorganic hydrate, the foamable composition was used in the same manner as in Example 1, but the curing and foaming process did not proceed smoothly and a foam sheet could not be formed.

[0161] Comparative Example 4.

[0162] An attempt was made to prepare a foamable composition in the same manner as in Example 1, except that a method was used. replace As an inorganic hydrate, it undergoes some solidification and foaming during the formulation process, making it impossible to properly form foamable compositions and foam sheets.

[0163] The measurement results of the examples and comparative examples (excluding comparative examples 3 and 4) are summarized in Table 3 below. In Table 3, the coating thickness is the layer thickness of the foamable composition coated on the release-treated PET film during the foaming sheet manufacturing process before curing and foaming, and the foaming thickness is the thickness of the foamed sheet after curing and foaming.

[0164] Similarly, in Table 3 below, the density unit is g / cm³. 3 .

[0165] In addition, the foaming scale-up ratio is a value obtained by dividing the foaming thickness by the coating thickness.

[0166] [Table 3]

[0167]

[0168] The results in Table 3 show that by selecting a combination of polyorganosiloxane components and inorganic hydrates, foam sheets with low density and excellent flame retardancy can be obtained.

[0169] For example, the foamable composition of Comparative Example 1, which does not contain any inorganic hydrates, cannot ensure a high foaming scale-up even under the same foaming conditions as in Example 1, and therefore the foam sheet has a high density.

[0170] In Comparative Example 2, which contained the same amount of inorganic hydrate as in Example 1, a suitable foaming scale-up could not be ensured under the same conditions as in Example 1, and therefore, a foamed sheet with low density could not be obtained. As described above, in Comparative Examples 3 and 4, it was not possible to produce a foamable composition or a foamed sheet.

Claims

1. A foamable composition comprising: Polyorganosiloxane components; and The following are hydrates of chemical formula 1: [Chemical Formula 1] wherein said M is a metal cation, said X is an anion, said r and said s are numbers satisfying wherein said p is the oxidation number of said metal cation, and said q is the oxidation number of said anion, and said n is a number of 8 or more.

2. The foamable composition according to claim 1, wherein the polyorganosiloxane component comprises siloxane units containing silicon-bonded hydrogen, siloxane units containing silicon-bonded hydroxyl groups, and siloxane units containing silicon-bonded alkenyl groups.

3. The foamable composition according to claim 2, satisfying formulas 1 to 3: [Formula 1] [Equation 2] [Formula 3] wherein H, OH, and V represent the total number of moles of silicon-bonded hydrogen, silicon-bonded hydroxyl groups, and silicon-bonded alkenyl groups in the polyorganosiloxane component, respectively.

4. The foamable composition according to claim 3, wherein the amount of silicon-bonded hydroxyl groups in the polyorganosiloxane component is in the range of 0.05 mmol / g to 5 mmol / g.

5. The foamable composition according to claim 1, wherein M in chemical formula 1 is selected from one or more of alkali metal ions, alkaline earth metal ions, post-transition metal ions, and metalloid ions.

6. The foamable composition according to claim 1, wherein M in chemical formula 1 is selected from two or more of alkali metal ions, alkaline earth metal ions, post-transition metal ions, and metalloid ions.

7. The foamable composition according to claim 1, wherein M in chemical formula 1 comprises alkali metal ions and post-transition metal ions.

8. The foamable composition according to claim 1, wherein M in chemical formula 1 is a cation of a metal belonging to period 2 to period 4 of the periodic table.

9. The foamable composition of claim 1, wherein the X in Chemical Formula 1 is one or more selected from the group consisting of halide anions, , , , , , and .

10. The foamable composition according to claim 1, wherein the D50 particle size of the inorganic hydrate is in the range of 1 μm to 500 μm.

11. The foamable composition according to claim 1, wherein the inorganic hydrate is included in an amount of 0.5 parts by weight to 100 parts by weight relative to 100 parts by weight of the polyorganosiloxane component.

12. The foamable composition according to claim 1, further comprising flame-retardant particles.

13. The foamable composition according to claim 12, wherein the D50 particle size of the flame retardant particles is in the range of 1 μm to 150 μm.

14. The foamable composition according to claim 12, wherein the flame-retardant particles are metal hydroxide particles.

15. The foamable composition according to claim 1, further comprising inorganic particles with a D50 particle size of 1 nm to 1,000 nm.

16. A foaming sheet comprising: Polyorganosiloxane alkyl groups; and Inorganic hydrates dispersed in the matrix wherein the foamed sheet has a flame retardant rating of VI or V0 according to the UL 94 vertical burning test standard, and the foamed sheet has a density of 0.45 g / cm 3 or less.

17. The foamed sheet according to claim 16, wherein it is a foamed product of the foamable composition according to any one of claims 1 to 15.

18. A battery module comprising the foam sheet according to claim 16.

19. The battery module of claim 18, comprising a plurality of battery cells, wherein the foam sheet is present between some of the battery cells.

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