Flame retardant surface pressure pad for battery

Abstract

The present invention relates to a flame retardant surface pressure pad for a battery, comprising a polymer foam impregnated with a flame retardant which is an inorganic phosphorus binder, being positioned between secondary battery cells or modules for an electric vehicle, an energy storage system (ESS) or the like, and thus preventing or delaying thermal runaway.

Description

Flame-retardant surface pressure pads for batteries

[0001] The present invention relates to a flame-retardant surface pressure pad for batteries comprising a polymer foam impregnated with a flame retardant, which is an inorganic phosphorus-based binder, and positioned between battery cells or between modules of secondary batteries such as electric vehicles and energy storage systems (ESS) to prevent or delay thermal runaway phenomena.

[0002] Generally, electric vehicles or energy storage systems (ESS) contain rechargeable batteries to supply electrical energy. Since these batteries consist of a positive electrode, a negative electrode, a separator, and an electrolyte, the possibility of fire occurring due to reasons such as overload, overcharging, or impact cannot be ruled out. If a fire occurs in any one battery cell, the affected cell swells up, transferring flames and heat to adjacent battery cells, which eventually spreads the fire to the entire battery and causes the vehicle to be completely burned.

[0003] In other words, if some battery cells show abnormal heat symptoms due to prolonged use of the battery or various causes, the temperature will continue to rise, and if it rises above the critical temperature, a thermal runaway phenomenon will occur. If the thermal runaway phenomenon originating from some battery cells spreads to adjacent battery cells within a short period of time, it can lead to the spread of flames and a rise in temperature throughout the battery, which can cause significant damage to human life and property.

[0004] Accordingly, to prevent the spread of fire in the event of a battery fire, flame-retardant materials are coated on the inner surface of the battery tray or the surface of the partition plate, or the battery tray itself is manufactured from flame-retardant materials; however, simply manufacturing with flame-retardant materials or coating has had limitations in suppressing the temperature rise of adjacent battery cells when thermal runaway occurs in a battery cell, and has not achieved the expected results.

[0005] Recently, research and development are being conducted to minimize damage caused by fire by applying materials such as flame-retardant polyurethane foam pads between the cells of electric vehicle battery modules.

[0006] In this regard, Korean Patent Publication No. 2022-0102771 discloses a battery safety sheet comprising a first skin layer formed of a first resin, a shielding layer formed by impregnating a carbon fiber woven material with a second resin, and a second skin layer formed of a third resin and laminated. However, since it is composed of multiple layers, the thickness of the sheet increases, and there is a disadvantage that the battery becomes larger when applied to a battery.

[0007] In addition, Korean Patent Publication No. 2021-0036990 discloses a polyurethane foam sheet comprising a base polyol component, a phosphorus polyol component, expandable graphite, and melamine, satisfying flame retardancy grade V0; however, graphite is not only an expensive material, but graphite-containing polyurethane foam sheets also have disadvantages such as limitations in controlling thickness and rebound characteristics and voltage resistance issues caused by graphite.

[0008] Accordingly, there is a need to develop a surface pressure pad with heat resistance capable of rapidly blocking the spread of flame and heat in the event of battery thermal runaway, excellent dimensional stability against volume changes of the battery cell, excellent resilience, and a thin thickness.

[0009] To overcome the aforementioned disadvantages, the present invention aims to provide a flame-retardant surface pressure pad for batteries that includes a polymer foam impregnated with a flame retardant, which is an inorganic phosphorus-based binder, thereby blocking the spread of flames and heat to surrounding battery cells or modules in the event of a fire in a battery cell, and thus preventing or delaying thermal runaway.

[0010] In order to solve the above problem,

[0011] In one embodiment, the present invention provides a flame-retardant surface pressure pad for a battery, comprising a polymer foam impregnated with a flame retardant which is an inorganic phosphorus-based binder, and positioned between battery cells or between modules.

[0012] The above flame retardant may include a phosphorus-based compound, an aluminum-containing compound, and water.

[0013] The above phosphorus compound may comprise one or more selected from the group consisting of phosphoric acid (or orthophosphoric acid), pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, polyphosphoric acid and trimetaphosphoric acid, phosphoric anhydride, trimethyl phosphate, hexamethylphosphoric triamid and combinations thereof.

[0014] The above aluminum-containing compound may comprise one or more selected from the group consisting of aluminum hydroxide, aluminum oxide (alumina), aluminum phosphate, and combinations thereof.

[0015] The above polymer foam is polyacetal, poly(C 1-6 Alkyl)acrylate, polyacrylic, polyamide, polyamideimide, polyanhydride, polyarylate, polyarylene ether, polyarylene sulfide, polybenzoxazole, polycarbonate, polyester, polyetheretherketone, polyetherimide, polyetherketoneketone, polyetherketone, polyethersulfone, polyisocyanurate, polyimide, poly(C 1-6It may comprise one or more selected from the group consisting of alkyl methacrylates, poly((meth)acrylic acid), polyphthalides, polyolefins (e.g., fluorinated polyolefins), polysilazanes, polystyrene, polysulfides, polysulfonamides, polysulfonates, polythioesters, polytriazines, polyureas, polyvinyl alcohols, polyvinyl esters, polyvinyl ethers, polyvinyl halides, polyvinyl ketones, polyvinylidene fluoride, polyvinyl esters, cross-linked poly(esters), epoxy, melamine, phenolic polymers, polyurethanes, urea-formaldehyde, silicones, natural rubbers, polychloroprene, ethylene-propylene-diene monomer (EPDM) rubbers, and combinations thereof.

[0016] The density of the above polymer foam is 100 to 400 kg / m³ 3 It could be.

[0017] The flame-retardant surface pressure pad may have a thickness of 0.5 to 5 mm.

[0018] The 20% Compression Force Deflection (CFD) of the above flame-retardant surface pressure pad is 0.5 to 5 kgf / cm² 2 It could be.

[0019] The flame-retardant surface pressure pad for batteries according to the present invention can prevent or delay thermal runaway by blocking the spread of flames and heat to surrounding battery cells when a fire occurs in a battery cell by applying a polymer foam impregnated with a flame retardant, which is an inorganic phosphorus binder, between battery cells.

[0020] In particular, the flame retardant is an inorganic phosphate binder formed by the reaction of an aluminum-containing compound and a phosphorus-based compound. By possessing the advantageous properties of aluminum metal and phosphate, it can improve the flame retardancy of the polymer foam upon impregnation. Additionally, due to its high adhesion and heat resistance, it can prevent damage to the polymer foam caused by thermal deformation even in high-temperature environments or situations involving sudden thermal shock, and can minimize the generation of toxic gases caused by fire in the event of a fire.

[0021] In addition, the flame-retardant surface pressure pad for batteries according to the present invention has elasticity and resilience capable of responding to volume changes of battery cells, and can manufacture a thin and light flame-retardant surface pressure pad using a material that is cheaper than conventional metal, aerogel, and carbon materials.

[0022] FIG. 1 is a schematic cross-sectional view of a flame-retardant surface pressure pad (a) and a flame-retardant surface pressure pad (b) located between a battery cell according to the present invention.

[0023] Figure 2 shows a photograph of a flame retardancy test according to an embodiment of the present invention.

[0024] Figure 3 shows a graph of a thermal insulation test according to an embodiment of the present invention.

[0025] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description.

[0026] However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0027] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0028]

[0029] The present invention will be described in detail below.

[0030]

[0031] The present invention provides a flame-retardant surface pressure pad for a battery, comprising a polymer foam impregnated with a flame retardant which is an inorganic phosphorus-based binder, and positioned between battery cells or between modules.

[0032] Referring to FIG. 1, the flame-retardant surface pressure pad (10) according to the present invention comprises a compressible polymer foam having pores (11) impregnated with a flame retardant. In the present invention, “polymer foam” refers to a polymer material having a porous or porous structure, and the pores within the polymer foam may be open, closed, or a combination thereof. At least some of the pores may be open and extend through the compressible polymer foam.

[0033] The flame-retardant surface pressure pad (10) may be formed by impregnating a polymer foam with the flame retardant, thereby allowing the flame retardant to penetrate or coat the pores within the polymer foam to improve the flame retardancy of the flame-retardant surface pressure pad (10).

[0034] Additionally, the flame-retardant surface pressure pad (10) can be applied between the battery cells (20) to block the spread of flames and heat to surrounding battery cells when a fire occurs in the battery cells (20), thereby preventing or delaying the thermal runaway phenomenon, and the compressible polymer foam of the flame-retardant surface pressure pad (10) may have elasticity and resilience capable of responding to volume changes of the battery cells (20).

[0035] The density of the above polymer foam is 100 to 400 kg / m³ 3 It may be. For example, the density of the polymer foam is 100 to 300 kg / m³. 3 , 100 to 200 kg / m² 3 , 100 to 150 kg / m² 3 , 150 to 400 kg / m² 3 , 150 to 300 kg / m² 3 or 150 to 200 kg / m² 3 It may be possible. To provide the desired compression characteristics within the polymer foam, it is desirable that the pore size and distribution be substantially uniform across the entire flame-retardant surface pressure pad.

[0036] As the density of the above polymer foam increases, the thermal insulation is superior, which has the advantage of allowing a reduction in the amount of flame retardant impregnated compared to a low-density polymer foam; however, the compression characteristics may be reduced. By utilizing these characteristics, it is possible to control the CFD values, flame resistance, and thermal insulation properties to suit the purpose depending on the density of the polymer foam used in the above flame-retardant surface pressure pad.

[0037] The flame-retardant surface pressure pad may have a thickness of 0.5 to 5 mm or less, and within the above range, it provides desired characteristics and minimizes the thickness, so that, for example, the battery size can be reduced by applying the flame-retardant surface pressure pad of the present invention to a battery of an electric vehicle where miniaturization of the battery size is required.

[0038] The flame-retardant surface pressure pad may have a thickness of 0.5 to 4 mm, 0.5 to 3 mm, 0.5 to 2 mm, 0.5 to 1 mm, 1 to 5 mm, 1 to 4 mm, 1 to 3 mm, 1 to 2 mm, 2 to 5 mm, 2 to 4 mm, 2 to 3 mm, 3 to 5 mm, or 4 to 5 mm.

[0039] The 20% Compression Force Deflection (CFD) of the above flame-retardant surface pressure pad is 0.5 to 5 kgf / cm² 2 It may be. For example, the compressive repulsion force of the flame-retardant surface pressure pad is 0.5 to 4 kgf / cm² 2 , 0.5 to 3 kgf / cm² 2 , 0.5 to 2 kgf / cm² 2 , 0.5 to 1 kgf / cm² 2 , 1 to 5 kgf / cm² 2 , 1 to 4 kgf / cm² 2 , 2 to 3 kgf / cm² 2 , 3 to 5 kgf / cm² 2 or 4 to 5 kgf / cm² 2 It could be.

[0040] The above 20% compressive rebound force (compressive deformation) refers to a measurement of the permanent deformation of the original height of the polymer foam due to bending or collapse of pores within the polymer foam after continuous compression (the degree of compression is 20% of the specimen thickness). The flame-retardant surface pressure pad according to the present invention can exhibit the required soft properties and excellent impact resistance, etc., as the compressive rebound force is within the above range, even though it is impregnated with the flame retardant.

[0041] The above polymer foam is polyacetal, poly(C 1-6 Alkyl)acrylate, polyacrylic, polyamide, polyamideimide, polyanhydride, polyarylate, polyarylene ether, polyarylene sulfide, polybenzoxazole, polycarbonate, polyester, polyetheretherketone, polyetherimide, polyetherketoneketone, polyetherketone, polyethersulfone, polyisocyanurate, polyimide, poly(C 1-6It may comprise one or more selected from the group consisting of alkyl methacrylates, poly((meth)acrylic acid), polyphthalides, polyolefins (e.g., fluorinated polyolefins), polysilazanes, polystyrene, polysulfides, polysulfonamides, polysulfonates, polythioesters, polytriazines, polyureas, polyvinyl alcohols, polyvinyl esters, polyvinyl ethers, polyvinyl halides, polyvinyl ketones, polyvinylidene fluoride, polyvinyl esters, cross-linked poly(esters), epoxy, melamine, phenolic polymers, polyurethanes, urea-formaldehyde, silicones, natural rubbers, polychloroprene, ethylene-propylene-diene monomer (EPDM) rubbers, and combinations thereof.

[0042] Preferably, the polymer foam may include MCPU foam (Microcellular polyurethane form), polyurethane foam, or silicone foam. Since the cell size of the MCPU foam is fine, it is difficult to impregnate it with an impregnation solution containing solids and binders in the micron range; however, since the flame retardant according to the present invention is an impregnation solution containing nano-sized solids, it can penetrate and settle into the fine pores of the MCPU foam, thereby enabling impregnation.

[0043] The flame-retardant surface pressure pad described above can control CFD values, density, flame resistance, and thermal insulation properties to suit the purpose by adjusting the amount of nano-sized solids within the polymer foam according to the amount of flame retardant impregnated. For example, the higher the amount of impregnated solids per unit area of ​​the polymer foam, the better the thermal insulation and the higher the CFD value may be.

[0044] The above flame retardant may include phosphorus-based compounds, aluminum-containing compounds, and water.

[0045] The flame retardant may be a reactant obtained by reacting a phosphorus-based compound, an aluminum-containing compound, and water, and may additionally include colloidal silica in the reactant.

[0046] The above flame retardant is an inorganic phosphate binder formed by the reaction of an aluminum-containing compound and a phosphorus-based compound. By possessing the advantageous properties of aluminum metal and phosphate, it can improve the flame retardancy of the polymer foam upon impregnation. Additionally, due to its high adhesion and heat resistance, it can prevent damage to the polymer foam caused by thermal deformation even in high-temperature environments or situations involving sudden thermal shock, and can minimize the generation of toxic gases caused by fire in the event of a fire.

[0047] Specifically, the flame retardant can be manufactured by mixing the phosphorus-containing compound with water to prepare an aqueous phosphoric acid solution, and then reacting the aqueous phosphoric acid solution with the aluminum-containing compound to form a phosphoric acid binder (primary reactant). Finally, the flame retardant can be manufactured by mixing the phosphoric acid binder with the colloidal silica (secondary reactant).

[0048] The above primary reactant may be a mixture of a phosphorus-based compound, an aluminum-containing compound, and water, stirred at 40 to 60°C to carry out a first reaction, and then stirred at 80 to 100°C to carry out a second reaction until it becomes transparent.

[0049] After carrying out the first reaction, a second reaction may be carried out for 2 to 3 hours until it becomes transparent, and water resistance may be improved by performing a phase transition reaction through the first and second reactions.

[0050] The flame retardant may comprise 40 to 55 weight% of the phosphorus-based compound; 8 to 20 weight% of the aluminum-containing compound; 10 to 20 weight% of the water; and 20 to 25 weight% of the colloidal silica.

[0051] Here, if the aluminum-containing compound is added in an amount of less than 8 weight%, a problem arises in which the brittleness of the flame retardant surface is reduced, and if it exceeds 20 weight%, a problem arises in which a transparent liquid cannot be obtained during the reaction with the acid. At this time, the meaning of reduced brittleness is that the thermal expansion coefficient of the polymer foam and the thermal expansion coefficient of the flame retardant are different, and as the degree of expansion of the polymer foam and the flame retardant differs, a problem arises in which the flame retardant detaches from the polymer foam.

[0052] The above aluminum-containing compound may comprise one or more selected from the group consisting of aluminum hydroxide, aluminum oxide (alumina), aluminum phosphate, and combinations thereof. In particular, the aluminum phosphate may contain phosphoric acid in addition to aluminum to further improve flame retardancy.

[0053] The phosphorus (P) contained in the aforementioned phosphorus-based compound plays a role in delaying combustion or preventing the spread of combustion when applied to combustible materials. Phosphoric acid-based flame retardants containing such phosphorus (P) are known to be utilized as effective flame retardant materials by blocking hydrocarbons forming the framework of combustible materials from further participating in combustion reactions through the formation of a char layer via the dehydration of polymetaphosphoric acid, which is a principle of the flame retardancy mechanism. Accordingly, the flame retardant can improve the flame retardancy of polymer foam by utilizing a phosphorus-based compound containing phosphorus (P).

[0054] The above phosphorus compound may comprise one or more selected from the group consisting of phosphoric acid (or orthophosphoric acid), pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, polyphosphoric acid and trimetaphosphoric acid, phosphoric anhydride, trimethyl phosphate, hexamethylphosphoric triamid and combinations thereof.

[0055] The above water may be included in an amount of 10 to 20 weight percent, so as to ensure that the phosphorus-containing compound is completely dissolved in water. At this time, the water may include purified water or distilled water.

[0056] The above colloidal silica is added to prevent the polymer foam from being over-corroded by the phosphoric acid of phosphorus-based compounds, and can serve to lower the acidity of the phosphoric acid.

[0057] The pH of the flame retardant may be 2.5 to 5. The primary reactant, formed by reacting the phosphorus-based compound, the aluminum-containing compound, and water, may have a pH of 1 to 2 due to the phosphoric acid of the phosphorus-based compound, but the pH may be adjusted to a range of 2.5 to 5 by the colloidal silica. For example, the pH may be 2.5 to 4, 2.5 to 3.5, 3 to 4, or 4 to 5.

[0058] If the above colloidal silica is added in an amount of less than 20 weight%, the flame retardant may excessively corrode the polymer foam, causing a problem of degrading the physical properties of the polymer foam; and if the above colloidal silica is added in an amount exceeding 25 weight%, the surface area of ​​the polymer foam in contact with the flame retardant may decrease, causing a problem of reduced bonding strength between the flame retardant and the polymer foam.

[0059] The above colloidal silica may have a pH of 8 to 10 and may include, for example, selected from the group consisting of Snowtex 40, SS Sol 30A and combinations thereof.

[0060] The amount of substance in each of the primary reactant and the secondary reactant of the flame retardant may comprise 45 to 65 weight% of the phosphorus-based compound; 15 to 25 weight% of the aluminum-containing compound; and 13 to 23 weight% of the water in the primary reactant, and may comprise 70 to 85 weight% of the primary reactant and 15 to 30 weight% of the colloidal silica in the secondary reactant.

[0061] The reaction molar ratio of the aluminum-containing compound and the phosphorus-containing compound may be 1:2 to 5. The flame retardant may have stable viscosity at the reaction molar ratio within the above range and may improve heat resistance. For example, the flame retardant may be one in which the reaction molar ratio of the aluminum-containing compound and the phosphorus-containing compound falls within an equivalent range of 1:2 to 5, 1:2 to 4, 1:2 to 3.5, 1:3 to 5, or 1:3 to 4.

[0062] The flame retardant is in a liquid state, and the colloidal silica may improve storage stability. To manufacture the flame retardant in a liquid state, the colloidal silica is added to increase the solid content and control the viscosity, thereby improving storage stability even in the liquid state and also serving to improve heat resistance.

[0063] The flame-retardant surface pressure pad for batteries according to the present invention can prevent or delay thermal runaway by blocking the spread of flames and heat to surrounding battery cells when a fire occurs in a battery cell by applying a polymer foam impregnated with a flame retardant, which is an inorganic phosphorus binder, between battery cells.

[0064] In addition, the flame-retardant surface pressure pad for batteries according to the present invention has elasticity and resilience capable of responding to volume changes of battery cells, and can manufacture a thin and light flame-retardant surface pressure pad using a material that is cheaper than conventional metal, aerogel, and carbon materials.

[0065]

[0066] The present invention will be explained in more detail below through embodiments and the like, but the scope of the present invention is not limited by the embodiments presented below.

[0067]

[0068] [Example]

[0069] Preparation Example 1: Preparation of a flame retardant with a molar ratio of aluminum hydroxide to phosphoric acid of 1:2.3

[0070] To manufacture a flame retardant for impregnating a surface pressure pad, 103.09 kg of phosphoric acid was placed in a jacket tank and 36.01 kg of water was added while stirring. Subsequently, 30.90 kg of aluminum hydroxide (LS-100) was slowly added at room temperature, and a first reaction was carried out by raising the temperature of the reaction section of the jacket tank to 40 to 60°C and stirring. Then, the temperature of the reaction section was raised to 80 to 100°C and stirred until a transparent liquid phase was formed by a second reaction to form a first reaction product.

[0071] After cooling the temperature of the jacket tank to room temperature, 40.15 kg of colloidal silica (SNOWTEX-40) was mixed with 170.0 kg of the primary reactant to produce a secondary reactant, a liquid flame retardant for impregnation.

[0072]

[0073] Preparation Example 2: Preparation of flame-retardant pressure pads

[0074] Based on 1 cubic meter (1 m × 1 m × 1 m), the density is 200 K (kg / m³). 3 150 to 250 kg of the flame retardant for impregnation of Preparation Example 1 was impregnated into a polyurethane foam (Microcellular polyurethane foam, MCPU foam) and then dried. The flame retardant-impregnated polyurethane foam was processed to a size of 13 mm × 125 mm and a width of 2 mm to manufacture a flame-retardant surface pressure pad, and then its physical properties were verified according to the following experimental examples.

[0075]

[0076] Experimental Example 1: Flame Retardancy Test

[0077] To verify flame retardancy, a flame-retardant surface pressure pad (Example) prepared by impregnating 150 kg of the flame retardant used in Preparation Example 2 above and a polyurethane foam sheet not impregnated with the flame retardant (Comparative Example) were prepared as specimens. The shape of the specimens was observed by igniting them at a distance of 2 mm from the flame ball.

[0078] As shown in Figure 2 and Table 1, the comparative example caught fire and burned, whereas the example only produced soot from the flame and did not catch fire or burn.

[0079] In addition, UL-94 V (Vertical burning test) tests were conducted along with comparative examples by varying the flame retardant impregnation amount relative to the polyurethane foam (MCPU foam) density, and the experimental results are shown in Table 1 below. In Table 1, the flame retardant impregnation amount is expressed as the amount relative to the polyurethane foam (MCPU foam) density; for example, with an MCPU foam density of 200 kg / m³ 3 In this, 100% of the flame retardant amount indicates that the amount of flame retardant is 200 kg.

[0080] As shown in Table 1 below, the UL-94 V (Vertical burning test) test results showed that the examples impregnated with flame retardant achieved a flame retardancy of V0 grade, while the comparative example not impregnated with flame retardant showed significantly lower flame retardancy.

[0081]

[0082]

[0083] Experimental Example 2: Thermal insulation test

[0084] To conduct a thermal insulation test, a flame-retardant surface pressure pad (Example) prepared by impregnating 150 kg of the flame retardant used in Preparation Example 2 and a polyurethane foam sheet not impregnated with the flame retardant (Comparative Example) were prepared as specimens. The prepared specimens were installed vertically, and an aluminum plate (thickness: 1 mm) of the same size as the specimen was placed to touch the front and back surfaces of the specimen. Then, a fire was ignited on one side of the specimen at a distance of 2 mm from the flame bulb, and the back surface temperature was measured for approximately 5 minutes to conduct the thermal insulation test. The results of the thermal insulation test are shown in Table 2 and Figure 3 below.

[0085]

[0086] Referring to Table 2 and Figure 2, the comparative example (CH1) was measured at 221.68°C at the moment of ignition, and the temperature rose to approximately 760°C in less than 1 second, after which it showed a temperature of approximately 800°C or higher, with a maximum value of 991.12°C. On the other hand, the example (CH2) was measured at 28.65°C at the moment of ignition and then rose slowly, and although the rate of increase slightly increased when about 3 minutes had passed since ignition, the maximum value was 105.95°C.

[0087] As a result of evaluating thermal insulation performance, it was found that impregnating the polyurethane foam with a flame retardant (Example, CH2) improved flame retardancy, resulting in excellent thermal insulation effects that prevent flame and heat transfer by preventing the foam from burning. Accordingly, when the flame-retardant surface pressure pad of the present invention is used in a battery, it can prevent or delay thermal runaway by blocking the spread of flame and heat to surrounding battery cells in the event of a fire.

[0088]

[0089] Experimental Example 3: 20% Compression Force Deflection (CFD) Experiment

[0090] In order to measure the compressive rebound force of the flame-retardant surface pressure pad prepared in Manufacturing Example 2 above, specimens satisfying the polyurethane foam (MCPU foam) density and the amount of impregnated flame retardant in Table 3 below were each prepared (size: 50 mm × 50 mm, thickness: approximately 4 mm), and then the compressive rebound force was measured according to ASTM D3574 standards (using the GNT-300 equipment of the Gana testing machine, compression speed: 8 mpm, compression degree: 20% of the specimen thickness).

[0091] Table 3 below shows the 20% Compressive Rebound Force (CFD) according to specimen conditions (Unit: kgf / cm² 2 The amount of flame retardant represents the amount relative to the density of the polyurethane foam (MCPU foam). For example, at an MCPU foam density of 200 K, 100% of the flame retardant amount indicates that the amount of flame retardant is 200 Kg.

[0092] Referring to Table 3, the compressive repulsion is 1.5 to 7 kgf / cm² 2 It indicates that the higher the MCPU foam density and the greater the amount of flame retardant, the higher the value is.

[0093] The appropriate compressive rebound force for use as a flame-retardant pressure pad is 3 kgf / cm² 2The sample in the box of Table 3 was the most suitable for use as a surface pressure pad, having flame retardancy at 750°C or higher.

[0094] Compressive repulsion is 3 kgf / cm² 2 If it exceeds, the MCPU foam may not contract when the volume of the battery cell expands during charging and discharging, which may put strain on the battery cell, and the compressive repulsion force is 3 kgf / cm² 2 Samples that were not suitable despite being below this level were not suitable for use as flame-retardant surface pressure pads because they could not secure flame retardancy of 750°C or higher.

[0095]

[0096]

[0097]

[0098] Experimental Example 4: Comparison of Thermal Insulation Performance According to Polymer Foam Density and Flame Retardant Impregnation Amount

[0099] Based on 1 cubic meter (1 m × 1 m × 1 m), the density is 150 or 200 K (kg / m³). 3 The flame retardant for impregnation of Preparation Example 1 was impregnated into the MCPU foam according to the amounts shown in Table 4 below, and then dried. The flame retardant-impregnated polyurethane foam was processed to a size of 75 mm × 150 mm and a thickness of 2 mm to manufacture a flame-retardant surface pressure pad, and then a specimen was prepared by laminating a silicone skin with a thickness of 300 μm on the front and back sides of the flame-retardant surface pressure pad. After applying heat at 750°C at a distance of 2 mm to one side of the specimen, the time taken for the back side temperature to reach 200°C was measured.

[0100] Table 4 below shows the measurement results according to the conditions of polymer foam density and flame retardant impregnation amount.

[0101]

[0102] Referring to Table 4, for samples 1, 2, and 3, which had the same MCPU foam density of 200K, it was found that the time taken to reach 200℃ increased with increasing flame retardant impregnation amount, indicating that thermal insulation performance is superior with increasing impregnation amount. For samples 2 and 4, which had similar flame retardant impregnation amounts, it was found that the time taken to reach 200℃ increased with increasing MCPU foam density, indicating that thermal insulation performance is superior with increasing MCPU foam density. In other words, it is possible to produce flame-retardant surface pressure pads with superior thermal insulation performance by increasing the flame retardant impregnation amount and foam density.

[0103] In addition, when comparing samples 3 and 4, which took a similar amount of time to reach 200℃, it was found that when the foam density is high, the effect is similar even with a smaller amount of flame retardant impregnated compared to foam with low density.

[0104] The present invention can be widely used in the field of flame-retardant surface pressure pads for batteries.

Claims

1. Includes a polymer foam impregnated with a flame retardant which is an inorganic phosphorus binder, and Flame-retardant surface pressure pads for batteries located between battery cells or between modules.

2. In Paragraph 1, The flame retardant for a battery flame-retardant surface pressure pad comprises a phosphorus-based compound, an aluminum-containing compound, and water.

3. In Paragraph 2, The above-mentioned phosphorus compound comprises one or more selected from the group consisting of phosphoric acid (phosphoric acid or orthophosphoric acid), pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, polyphosphoric acid and trimetaphosphoric acid, phosphoric anhydride, trimethyl phosphate, hexamethylphosphoric triamid, and combinations thereof, a flame-retardant surface pressure pad for a battery.

4. In Paragraph 2, The above aluminum-containing compound comprises one or more selected from the group consisting of aluminum hydroxide, aluminum oxide (alumina), aluminum phosphate, and combinations thereof, for a flame-retardant surface pressure pad for a battery.

5. In Paragraph 1, The above polymer foam is polyacetal, poly(C 1-6 Alkyl)acrylate, polyacrylic, polyamide, polyamideimide, polyanhydride, polyarylate, polyarylene ether, polyarylene sulfide, polybenzoxazole, polycarbonate, polyester, polyetheretherketone, polyetherimide, polyetherketoneketone, polyetherketone, polyethersulfone, polyisocyanurate, polyimide, poly(C 1-6 A flame-retardant surface pressure pad for a battery comprising one or more selected from the group consisting of alkyl methacrylate, poly((meth)acrylic acid), polyphthalide, polyolefin (e.g., fluorinated polyolefin), polysilazane, polystyrene, polysulfide, polysulfonamide, polysulfonate, polythioester, polytriazine, polyurea, polyvinyl alcohol, polyvinyl ester, polyvinyl ether, polyvinyl halide, polyvinyl ketone, polyvinylidene fluoride, polyvinyl ester, cross-linked poly(ester), epoxy, melamine, phenolic polymer, polyurethane, urea-formaldehyde, silicone, natural rubber, polychloroprene, ethylene-propylene-diene monomer (EPDM) rubber, and combinations thereof.

6. In Paragraph 1, The density of the above polymer foam is 100 to 400 kg / m³ 3 Flame-retardant surface pressure pad for batteries.

7. In Paragraph 1, The flame-retardant surface pressure pad above is a flame-retardant surface pressure pad for batteries having a thickness of 0.5 to 5 mm.

8. In Paragraph 1, The 20% Compression Force Deflection (CFD) of the above flame-retardant surface pressure pad is 0.5 to 5 kgf / cm² 2 Flame-retardant surface pressure pad for batteries.

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