Fireproof pad, method for manufacturing same, and secondary battery

Abstract

A fireproof pad according to the present invention comprises: a first layer including a nonflammable material; a second layer including silicone and a flame retardant in the form of a carbonate; and a third layer including a silicone-aerogel composite, wherein the silicone-aerogel composite has an aerogel content of 0.5 wt% to 40 wt% and a silicone content of 60 wt% to 99.5 wt% with respect to the total weight, and at least one of each of the first layer, the second layer, and the third layer is laminated.

Description

Refractory pad, method for manufacturing the same, and secondary battery

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0074277, filed June 7, 2024, and Korean Patent Application No. 10-2025-0072846, filed June 4, 2025, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a fireproof pad, a method for manufacturing the same, and a secondary battery, and more specifically, to a fireproof pad including a flame-retardant layer, a method for manufacturing the same, and a secondary battery including the fireproof pad.

[0004] As technological developments and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting significant attention as an energy source not only for mobile devices such as cell phones, digital cameras, laptops, and wearable devices, but also for powertrains such as electric bicycles, electric cars, and hybrid electric vehicles.

[0005] Secondary battery cells are manufactured by embedding electrode assemblies together with electrolytes in a secondary battery case, and the electrode assemblies are manufactured by stacking and / or winding a cathode, a separator, and anode. The manufactured battery cells are stacked in multiple pieces to form a battery module or battery pack.

[0006] As the cells are driven, heat may be generated in the battery cells, and if the heat is transferred to and accumulated in adjacent battery cells, battery thermal propagation may occur.

[0007] Preventing battery thermal runaway is crucial for the safety of electric vehicle batteries, and extensive research is underway. Currently, the industry utilizes silicone or polyurethane materials interposed between battery cells as fire-resistant pads. However, these materials are inadequate in preventing the ultra-high-temperature flames that form during battery thermal runaway. Therefore, research into highly fire-resistant fire-resistant pads and their manufacturing methods continues.

[0008] The present invention provides a fire-resistant pad having improved flame retardant and insulating effects, including a flame retardant layer, and a method for manufacturing the same.

[0009] In addition, the present invention provides a secondary battery capable of effectively blocking heat transfer or thermal runaway between unit cells, including the refractory pad.

[0010] The fireproof pad of the present invention comprises a first layer comprising a non-combustible material; a second layer comprising a carbonate-based flame retardant and a silicone resin; and a third layer comprising a silicone-aerogel composite including a silicone resin and an aerogel; wherein the silicone-aerogel composite has an aerogel content of 0.5 wt% or more and 40 wt% or less based on the total weight of the third layer.

[0011] In one embodiment, the silicone-aerogel composite may comprise a silicone resin in an amount of from 60 wt% to 99.5 wt%, based on the total weight of the third layer. In a more specific example, the silicone-aerogel composite may comprise aerogel in an amount of from 15 wt% to 30 wt%, and silicone resin in an amount of from 70 wt% to 85 wt%, based on the total weight of the third layer.

[0012] In one embodiment, the flame retardant may include a metal carbonate, for example, a carbonate of an alkali metal or alkaline earth metal. Specific examples of such flame retardants include at least one selected from the group consisting of X2CO3 (X=Na, K, Rb, Cs), XHCO3 (X=Na, K, Rb, Cs), YCO3 (Y=Be, Mg, Ca, Sr, Ba), and Y(HCO3)2 (Y=Be, Mg, Ca, Sr, Ba).

[0013] In one embodiment, the non-combustible material may refer to an inorganic material that does not combust at any temperature to which the refractory pad or the secondary battery including the refractory pad is exposed, for example, at a temperature of 1000°C or lower under atmospheric pressure, or at a temperature of 800°C or lower. The non-combustible material may be at least one selected from the group consisting of ceramic paper, ceramic wool, mica (mcia) sheet, and glass fiber.

[0014] In one embodiment, the first layer, the second layer, and the third layer may be laminated in that order.

[0015] In one embodiment, the second layer, the first layer, and the third layer may be laminated in that order.

[0016] In one embodiment, the first layer, the second layer, the third layer, the second layer, and the first layer may be laminated in that order.

[0017] In one embodiment, the second layer, the first layer, the third layer, the first layer, and the second layer may be laminated in that order.

[0018] In one embodiment, the first layer, the third layer, the second layer, the third layer, and the first layer may be laminated in that order.

[0019] In one embodiment, the second layer, the third layer, the first layer, the third layer, and the second layer may be laminated in that order.

[0020] In one embodiment, the thickness of each of the first layer, the second layer, and the third layer may be 0.1 mm or more and 5 mm or less.

[0021] A method for manufacturing a fire-resistant pad of the present invention comprises: forming a first layer comprising a non-combustible material; forming a second preliminary layer comprising a carbonate-based flame retardant and a silicone resin; forming a solid silicone-aerogel composite by mixing a liquid solvent-free silicone resin and aerogel particles, and forming a third preliminary layer comprising the silicone-aerogel composite; laminating at least one of each of the first layer, the second preliminary layer, and the third preliminary layer; and curing the second preliminary layer and the third preliminary layer to form a second layer and a third layer, respectively.

[0022] In one embodiment, in the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, the laminated second preliminary layer and the third preliminary layer can be cured simultaneously.

[0023] In another embodiment, the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, may be performed before the laminating step.

[0024] At this time, in the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, the second preliminary layer and the third preliminary layer can be cured at different times.

[0025] Meanwhile, the present invention also provides a secondary battery comprising a plurality of unit cells; and a refractory pad according to any one of claims 1 to 14 formed between adjacent unit cells.

[0026] The fire-resistant pad of the present invention can exhibit excellent fire resistance, flame retardancy, and thermal insulation properties by including a first layer comprising a non-combustible material, a second layer comprising a flame retardant, and a third layer comprising a silicone aerogel.

[0027] According to the method for manufacturing a fireproof pad of the present invention, a method for manufacturing a fireproof pad having high process efficiency and excellent fire resistance can be provided.

[0028] FIGS. 1 to 6 are each a cross-sectional view of a refractory pad of one embodiment.

[0029] FIGS. 7 to 19 each schematically illustrate one step of a method for manufacturing a refractory pad according to one embodiment.

[0030] FIG. 20 is a photograph and schematic diagram of a device for evaluating and measuring the heat transfer inhibition characteristics of a refractory pad according to one embodiment of the invention.

[0031] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0032] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0033] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0034] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on" or "over" another part, this includes not only cases where it is "directly on" the other part, but also cases where there are other parts in between. When we say that a part is "directly on" another part, we mean that there are no other parts in between. Furthermore, when we say that a part is "on" or "over" a reference part, we mean that it is located above or below the reference part, and we do not necessarily mean that it is located "above" or "over" the reference part in the opposite direction of gravity.

[0035] Additionally, throughout the specification, whenever a part is said to “include” a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0036]

[0037] Hereinafter, the refractory pad of the present invention and its manufacturing method will be described.

[0038] The refractory pad of the present invention,

[0039] A first layer comprising a non-combustible material;

[0040] A second layer comprising a carbonate flame retardant and a silicone resin; and

[0041] A third layer comprising a silicone-aerogel composite including silicone resin and aerogel;

[0042] The above silicone-aerogel composite has an aerogel content of 0.5 wt% or more and 40 wt% or less based on the total weight of the third layer.

[0043] In a specific embodiment, the silicone-aerogel composite may comprise silicone in an amount of 60 wt% or more and 99.5 wt% or less based on the total weight of the third layer.

[0044]

[0045] The refractory pad of the present invention comprises a first layer, a second layer, and a third layer, and has a structure in which at least one of the first layer, the second layer, and the third layer is laminated. That is, in one embodiment, each of the first layer, the second layer, and the third layer may be present one at a time, or in another embodiment, any one of the first layer, the second layer, and the third layer may be present two or more times.

[0046] The first layer comprises a non-combustible material. The non-combustible material may refer to, for example, an inorganic material that does not combust at all temperatures to which the refractory pad or the secondary battery including the same is exposed, for example, at a temperature of 1000°C or lower under atmospheric pressure, or at a temperature of 800°C or lower. The non-combustible material may be at least one selected from the group consisting of ceramic paper, ceramic wool, mica (MCIA) sheets, and glass fibers. The first layer may exhibit a flame retardant effect by including the non-combustible material.

[0047] The second layer includes a flame retardant in the form of a carbonate and a silicone resin. The flame retardant in the form of a carbonate may include a metal carbonate, for example, a carbonate of an alkali metal or an alkaline earth metal. Specific examples of such flame retardants may include at least one selected from the group consisting of X2CO3 (X=Na, K, Rb, Cs), XHCO3 (X=Na, K, Rb, Cs), YCO3 (Y=Be, Mg, Ca, Sr, Ba), and Y(HCO3)2 (Y=Be, Mg, Ca, Sr, Ba). For example, the flame retardant may include Na2CO3, NaHCO3, CaCO3, Ca(HCO3)2), KHCO3, or K2CO3.

[0048] Flame retardants can exhibit flame retardant effects by forming water and carbon dioxide during a thermal decomposition reaction, and specifically, the thermal decomposition reaction can begin at 80°C to 100°C. For example, the thermal decomposition reaction of the flame retardant NaHCO3 is as shown in the following reaction scheme 1.

[0049] [Reaction Formula 1]

[0050] 2NaHCO3(s)→Na2CO3(s) + H2O(g) + CO2(g)

[0051] Additionally, the Na2CO3 produced in Reaction Scheme 1 can be thermally decomposed once more to produce carbon dioxide. In this way, NaHCO3 can produce water and carbon dioxide through two thermal decomposition processes, thereby enhancing its flame retardant effect.

[0052] The third layer comprises a silicone-aerogel composite. The silicone-aerogel composite of the present invention may be formed by mixing a silicone resin and an aerogel. For example, a liquid silicone resin in a solvent-free state and an aerogel are mixed to form a solid silicone-aerogel composite, and then the silicone-aerogel composite is cured to form the third layer.

[0053] Based on the total weight of the third layer including the silicone-aerogel composite, the content of the aerogel may be 0.5 wt% or more and 40 wt% or less, or 15 wt% or more and 30 wt% or less, and the content of the silicone resin may be 60 wt% or more and 99.5 wt% or less, or 70 wt% or more and 85 wt%. If the content of the aerogel is too small, the aerogel may not sufficiently envelop the silicone resin, making it difficult to form the silicone-aerogel composite, and furthermore, the insulating properties of the silicone-aerogel composite may be reduced. If the content of the aerogel is too large, it is difficult to shape the silicone-aerogel composite into a sheet shape, making it difficult to use it as an insulating layer.

[0054] Therefore, the third layer of the present invention comprises a silicone-aerogel composite, and based on the total weight of the silicone-aerogel composite, the content of the aerogel is 0.5 wt% or more and 40 wt% or less, and the content of the silicone resin is 60 wt% or more and 99.5 wt% or less, so that it can function as an insulating layer. The effects and manufacturing method according to the composition of the third layer will be described in detail later.

[0055] Meanwhile, the thickness of each of the first layer, the second layer, and the third layer may be 0.1 mm or more and 5 mm or less. The first layer, the second layer, and the third layer may have the same thickness, or at least one of them may have a different thickness from the others.

[0056]

[0057] The refractory pad of the present invention has a structure in which at least one of the first layer, second layer, and third layer described above is laminated. The laminated structure of the refractory pad is not particularly limited, and various laminated structures of the refractory pad of the present invention will be described below with reference to FIGS. 1 to 6.

[0058] FIGS. 1 to 6 are each a cross-sectional view of a refractory pad of one embodiment.

[0059] Referring to FIG. 1, a refractory pad (1) of one embodiment may be formed by sequentially stacking a first layer (10), a second layer (20), and a third layer (30).

[0060] Referring to FIG. 2, the refractory pad (1-a) of one embodiment may be formed by sequentially stacking a second layer (20), a first layer (10), and a third layer (30).

[0061] Referring to FIG. 3, the refractory pad (1-b) of one embodiment may be formed by sequentially stacking a first layer (10), a second layer (20), a third layer (30), a second layer (20), and a first layer (10).

[0062] Referring to FIG. 4, the refractory pad (1-c) of one embodiment may be formed by sequentially stacking a second layer (20), a first layer (10), a third layer (30), a first layer (10), and a second layer (20).

[0063] Referring to FIG. 5, the refractory pad (1-d) of one embodiment may be formed by sequentially stacking a first layer (10), a third layer (30), a second layer (20), a third layer (30), and a first layer (10).

[0064] Referring to FIG. 6, the refractory pad (1-e) of one embodiment may be formed by sequentially stacking a second layer (20), a third layer (30), a first layer (10), a third layer (30), and a second layer (20).

[0065] Meanwhile, FIGS. 1 to 6 are examples, and the refractory pad of the present invention may have various laminated structures not disclosed in FIGS. 1 to 6, as long as it includes a first layer (10), a second layer (20), and a third layer (30).

[0066] The fire-resistant pad of the present invention can exhibit excellent non-combustibility, flame retardancy, and thermal insulation properties by including a first layer (10), a second layer (20), and a third layer (30). In particular, the fire-resistant pad can generate non-combustible gases such as CO2 and water through thermal decomposition of a flame retardant when a flame occurs, thereby improving the flame retardancy and thermal insulation effects by including the second layer (20).

[0067] When the fireproof pad of the present invention is applied to a secondary battery in the form of a battery pack or the like, the fireproof pad can prevent the spread of flame and heat. Specifically, the fireproof pad of the present invention is arranged between unit battery cells included in the battery pack, and can effectively prevent the spread of flame when thermal runaway occurs inside the battery pack. In addition, the fireproof pad can include a third layer (30) including a silicone-aerogel composite, and can serve as an insulating layer, and can minimize heat transfer between unit cells, thereby preventing heat from being concentrated in a specific unit cell and preventing the occurrence of thermal runaway in advance.

[0068] To this end, the secondary battery may include a plurality of unit cells, and may include the refractory pad formed between some or all of the adjacent unit cells. However, since such a secondary battery may follow the configuration of a general secondary battery or battery pack except for the formation of the refractory pad, a detailed description thereof will be omitted.

[0069]

[0070] Meanwhile, the method for manufacturing the above-described refractory pad is as follows:

[0071] A step of forming a first layer comprising a non-combustible material;

[0072] A step of forming a preliminary second layer comprising a carbonate flame retardant and a silicone resin;

[0073] A step of forming a solid silicone-aerogel composite by mixing a liquid solvent-free silicone resin and aerogel particles, and forming a preliminary third layer including the silicone-aerogel composite;

[0074] A step of laminating at least one of each of the first layer, the second preliminary layer, and the third preliminary layer; and

[0075] A step of curing the second preliminary layer and the third preliminary layer to form a second layer and a third layer, respectively; is included.

[0076]

[0077] The step of forming a first layer including a non-combustible material is a step of forming the first layer described above on the refractory pad. The first layer may include at least one of mica fibers, glass fibers, basalt fibers, ceramic paper, and vermiculite-coated glass fiber cloth as the non-combustible material. For example, the first layer may be ceramic paper, vermiculite-coated glass fiber foil, or a blanket or sheet including ceramic fibers or ceramic wool. However, embodiments of the first layer are not limited thereto.

[0078] The step of forming a preliminary second layer including a carbonate-based flame retardant and a silicone resin includes a step of mixing the carbonate-based flame retardant and the silicone resin.

[0079] As already mentioned above, the flame retardant may be at least one selected from the group consisting of metal carbonates, for example, carbonates of alkali metals or alkaline earth metals, more specifically, X2CO3 (X=Na, K, Rb, Cs), XHCO3 (X=Na, K, Rb, Cs), YCO3 (Y=Be, Mg, Ca, Sr, Ba), and Y(HCO3)2 (Y=Be, Mg, Ca, Sr, Ba). For example, when manufacturing the preliminary second layer, Na2CO3, NaHCO3, CaCO3, Ca(HCO3)2), KHCO3, or K2CO3 may be used as the flame retardant.

[0080] Specifically, silicone resins include vinyl terminated polydimethylsiloxane resins (PDMS-vinyl terminated, ViMe2SiO(Me2SiO) X SiMe2Vi) can be used. In addition, a crosslinking agent and a catalyst can be additionally used for thermal curing of such silicone resin. The crosslinking agent used for thermal curing can be a silicone-based crosslinking agent containing at least one Si-H structure, for example, Polymethylhydrogen siloxane can be used. A platinum catalyst can be used as a catalyst.

[0081] Based on the total weight of the flame retardant and the silicone resin, the content of the flame retardant may be 1 wt% or more and 60 wt% or less, and the content of the silicone resin may be 40 wt% or more and 99 wt% or less. Based on the total weight of the flame retardant and the silicone resin, the content of the polydimethylsiloxane resin at the vinyl group terminal may be 40 wt% or more and 99 wt% or less, the content of the crosslinking agent may be 0 wt% or more and 10 wt% or less, and the content of the catalyst may be 0 wt% or more and 3 wt% or less.

[0082] For example, based on the total weight of the flame retardant and the silicone resin, the content of the flame retardant may be 30.1 wt%, the content of the vinyl-terminated polydimethylsiloxane resin may be 68.8 wt%, the content of the crosslinking agent may be 0.7 wt%, and the content of the catalyst may be 0.4 wt%, but the embodiment is not limited thereto.

[0083] A preliminary second layer can be formed by mixing the above carbonate-based flame retardant and silicone resin and then arranging them in a layer form. When the preliminary second layer is cured, the second layer can be formed as the thermosetting silicone resin is cured. Meanwhile, the curing temperature of the silicone resin can be controlled so that the flame retardant is not thermally decomposed during the curing process of the preliminary second layer. When the content of the catalyst contained in the silicone resin is controlled, the curing temperature of the silicone resin can be controlled. For example, when the catalyst content is 1 wt%, the curing temperature of the silicone resin is about 100°C, but when the catalyst content is 2 wt% to 3 wt%, the curing temperature of the silicone resin can be lowered to about 70 to 80°C. Accordingly, during the curing process of the preliminary second layer, the flame retardant is not thermally decomposed, and the silicone resin can be cured to form the second layer.

[0084] The step of forming a preliminary third layer comprising a silicone-aerogel composite includes the step of forming a silicone-aerogel composite. In the present invention, the silicone-aerogel composite is formed in a solid state by mixing a liquid, solvent-free silicone resin and aerogel particles.

[0085] In one embodiment, the aerogel may be silica gel. In one embodiment, the silicone resin is provided in a solvent-free liquid form and may be a solvent-free silicone resin ink. The silicone resin is specifically a vinyl terminated polydimethylsiloxane resin (PDMS-vinyl terminated, ViMe2SiO(Me2SiO) XThe polydimethylsiloxane resin may include a siloxane backbone, at least one vinyl group, and a weight average molecular weight of 500 g / mol or more and 100,000 g / mol or less. The crosslinking agent used for thermal curing may be a silicone-based crosslinking agent including at least one Si-H structure, for example, polymethylhydrogen siloxane. A platinum catalyst may be used as the catalyst.

[0086] During the mixing process of silicone resin and aerogel, the liquid silicone resin is surrounded by the high-surface-area aerogel, forming a solid silicone-aerogel composite. The solid silicone-aerogel composite may be, for example, in the form of a dispersed powder.

[0087] The silicone-aerogel composite may have an aerogel content of 0.5 wt% or more and 40 wt% or less, or 15 wt% or more and 30 wt% or less, and a silicone resin content of 60 wt% or more and 99.5 wt% or less, or 70 wt% or more and 85 wt% or less, based on the total weight of the third layer. If the aerogel content is too small, the aerogel may not sufficiently envelop the silicone resin, making it difficult to form the silicone-aerogel composite, and further reducing the insulating properties of the silicone-aerogel composite. If the aerogel content is too large, the adhesive properties of the silicone-aerogel composite may be reduced, and it may be difficult to form the third layer well.

[0088] In one embodiment, the content of the polydimethylsiloxane resin may be 47 wt% or more and 99.5 wt% or less, based on the total mass of the silicone-aerogel composite, the content of the crosslinking agent may be 0 wt% or more and 10 wt% or less, and the content of the catalyst may be 0 wt% or more and 3 wt% or less. This is an internal composition of the silicone resin having a content of 60 wt% or more and 99.5 wt% or less, based on the total mass of the silicone-aerogel composite.

[0089] The conventional wet manufacturing process of aerogel composites involves dispersing aerogel in a solvent, impregnating the fiber structure, growing the aerogel precursor, and drying the solvent. In this case, it takes about 1 to 3 days to grow the aerogel precursor on the surface of a fiber structure such as glass fiber, and since a process is required to selectively remove the solvent within the aerogel precursor using a supercritical fluid method, room temperature pressurization method, etc., the time required for the process and the cost are high. In contrast, the present invention forms a solid aerogel composite by mixing a solvent-free silicone resin (Silicone) and aerogel, so the process time is less than 10 minutes, and the conventional solvent removal process is omitted, simplifying the process compared to the wet manufacturing process, and having the advantage of relatively short process time and cost.

[0090] A silicone-aerogel composite can be layered to form a preliminary third layer. When the preliminary third layer is cured, the thermosetting silicone resin can be cured to form the third layer.

[0091] The step of laminating at least one of each of the first layer, the second preliminary layer, and the third preliminary layer is a step of laminating at least one first layer, at least one second preliminary layer, and at least one third preliminary layer. The laminating order is not particularly limited.

[0092] For example, the laminating step of one embodiment may be laminating a first layer, a preliminary second layer, and a preliminary third layer in that order. The laminating step of one embodiment may be laminating a preliminary second layer, a first layer, and a preliminary third layer in that order. The laminating step of one embodiment may be laminating a first layer, a preliminary second layer, a preliminary third layer, a preliminary second layer, and a first layer in that order. The laminating step of one embodiment may be laminating a preliminary second layer, a first layer, a preliminary third layer, a first layer, and a preliminary second layer in that order. The laminating step of one embodiment may be laminating a preliminary second layer, a preliminary third layer, a preliminary second layer, a preliminary third layer, and a first layer in that order. The laminating step of one embodiment may be laminating a preliminary second layer, a preliminary third layer, a first layer, a preliminary third layer, and a preliminary second layer in that order.

[0093] The step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, is a step of curing the second preliminary layer to form the second layer and curing the third preliminary layer to form the third layer. As described above, the second preliminary layer and the third preliminary layer include a thermosetting silicone resin, and each layer can be cured through a thermosetting process.

[0094] Meanwhile, the steps for curing the second preliminary layer and the third preliminary layer are performed independently. For example, the second preliminary layer and the third preliminary layer may be cured simultaneously. In this case, the curing step may be performed after the steps for laminating at least one each of the first layer, the second preliminary layer, and the third preliminary layer, and then the laminated second preliminary layer and the third preliminary layer may be cured simultaneously.

[0095] In another example, the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, may be performed before the laminating step. In this case, in the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, the second preliminary layer and the third preliminary layer may be cured at different times. Subsequently, at least one of each of the first to third layers may be laminated. In addition, the curing step may be performed during the laminating step, if necessary.

[0096]

[0097] Hereinafter, a method for manufacturing a refractory pad according to an embodiment will be described with reference to FIGS. 7 to 19. FIGS. 7 to 19 illustrate each step of a method for manufacturing a refractory pad (1) illustrated in FIG. 1 as an example. The description of the first layer (10), the preliminary second layer (21), the second layer (20), the silicone-aerogel composite (CM), and the third layer (30) below is identical to the above description, and a detailed description thereof will be omitted.

[0098] Figures 7 to 10 schematically illustrate one step of a method for manufacturing a refractory pad according to one embodiment.

[0099] Referring to Fig. 7, a preliminary second layer (21) can be laminated on a first layer (10) by a roll-to-roll process (RL) and thermal curing can be performed at the same time. Referring to Fig. 8, the preliminary second layer (21) is cured to form a second layer (20). Referring to Fig. 9, a silicone-aerogel composite (CM) can be applied on the second layer (20) by a roll-to-roll process (RL) and thermal curing can be performed at the same time. Hereinafter, the layer formed by the silicone-aerogel composite (CM) corresponds to the preliminary third layer described above. Referring to Fig. 10, the silicone-aerogel composite (CM) is cured to form a third layer (30), and a refractory pad (1) of one embodiment is manufactured. As shown in Figs. 7 to 10, the second layer (20) and the third layer (30) can be sequentially formed on the first layer (10) by a continuous roll-to-roll process. However, the method for manufacturing the refractory pad of one embodiment is not limited thereto.

[0100] Figures 11 to 14 schematically illustrate one step of a method for manufacturing a refractory pad according to one embodiment.

[0101] Referring to Fig. 11, after a preliminary second layer (21) is laminated on a first layer (10), the first layer (10) and the preliminary second layer (21) can be thermally compressed using a press (PR) method. Referring to Fig. 12, the preliminary second layer (21) is cured to form a second layer (20). Referring to Fig. 13, after a silicone-aerogel composite (CM) is applied and laminated on the second layer (20), the first layer (10), the second layer (20), and the silicone-aerogel composite (CM) can be thermally compressed using a press (PR) method. Referring to Fig. 14, the silicone-aerogel composite (CM) is cured to form a third layer (30), and a refractory pad (1) of one embodiment is manufactured. As shown in FIGS. 11 to 14, the second layer (20) and the third layer (30) can be sequentially formed on the first layer (10) through a continuous pressing process. However, the present invention is not limited thereto, and a method of sequentially stacking the preliminary second layer (21) and the silicone-aerogel composite (CM) on the first layer (10) and then pressing and thermally compressing them at once is also possible.

[0102] Figures 15 to 19 schematically illustrate one step of a method for manufacturing a refractory pad according to one embodiment.

[0103] Referring to FIGS. 15 and 16 together, a preliminary second layer (21) can be formed by laminating it on the first layer (10) without applying separate heat. Referring to FIG. 17, a third layer (30) that has been cured can be laminated on the preliminary second layer (21). That is, the curing step of the third layer (30) may be performed before the laminating step of the third layer (30). Thereafter, as shown in FIG. 18, the first layer (10), the preliminary second layer (21), and the third layer (30) can be pressed (PR) to thermally compress them and the preliminary second layer (21) can be cured. Referring to FIG. 19, the preliminary second layer (21) is cured to form the second layer (20), and a refractory pad (1) of one embodiment is manufactured.

[0104] Although a method for manufacturing a refractory pad according to an embodiment is described in FIGS. 7 to 19, this is an example of a manufacturing method, and the method for manufacturing the refractory pad is not limited thereto.

[0105] A method for manufacturing a fireproof pad according to one embodiment of the present invention can provide a method for manufacturing a fireproof pad having excellent fire resistance and insulation properties, including the steps described above, and can increase the efficiency of the process.

[0106]

[0107] Hereinafter, embodiments of the invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0108]

[0109] 1. Manufacturing of the insulation layer (third layer) of Manufacturing Examples 1 to 4 and Comparative Manufacturing Examples 1 to 4

[0110] Insulating layers of Manufacturing Examples 1 to 4 and Comparative Manufacturing Examples 1 to 4 were manufactured using the following methods.

[0111]

[0112] Manufacturing Example 1: Manufacturing of an Insulating Layer

[0113] A solid silicone-aerogel composite was formed by mixing a solvent-free silicone resin and aerogel at a weight ratio of 87.18:12.82. The silicone resin was PDMS resin, Dowsil of DOW. TM 7272 was used, and Dow Syl-off was used as a crosslinking agent. TM 7028 was used, and Dow's Syl-off was used as a Pt catalyst. TM 4000 was used. Cabot EV5200 was used as the aerogel.

[0114] The manufactured silicone-aerogel composite was subjected to a test at 150°C with a strength of 1.5 kgf / cm 2The insulating layer of Manufacturing Example 1 having a thickness of 0.7 to 2 mm was manufactured by hot-pressing for 30 seconds to form a pad and further heat-curing in an oven at 150°C for 10 minutes.

[0115]

[0116] Manufacturing Example 2: Manufacturing of an Insulating Layer

[0117] An insulating layer of Manufacturing Example 2 was manufactured in the same manner as the insulating layer of Manufacturing Example 1, except that the silicone resin and aerogel were mixed in a weight ratio of 83.61:16.39.

[0118]

[0119] Manufacturing Example 3: Manufacturing of an Insulating Layer

[0120] An insulating layer of Manufacturing Example 3 was manufactured in the same manner as the insulating layer of Manufacturing Example 1, except that the silicone resin and aerogel were mixed in a weight ratio of 80.31:19.69.

[0121]

[0122] Manufacturing Example 4: Manufacturing of an Insulating Layer

[0123] An insulating layer of Manufacturing Example 4 was manufactured in the same manner as the insulating layer of Manufacturing Example 1, except that the silicone resin and aerogel were mixed in a weight ratio of 75:25.

[0124]

[0125] Comparative Manufacturing Example 1: Manufacturing of Insulating Layer

[0126] Only silicone resin was used without aerogel. That is, the insulation layer of Comparative Manufacturing Example 1 was manufactured in the same manner as the insulation layer of Manufacturing Example 1, except that silicone resin was used instead of the silicone-aerogel composite in Manufacturing Example 1.

[0127]

[0128] Comparative Manufacturing Example 2: Manufacturing of Insulating Layer

[0129] An insulating layer of Comparative Manufacturing Example 2 was manufactured in the same manner as the insulating layer of Manufacturing Example 1, except that the silicone resin and aerogel were mixed in a weight ratio of 50:50. However, padding of the silicone-aerogel composite was not achieved.

[0130]

[0131] Comparative Manufacturing Example 3: Manufacturing of Insulating Layer

[0132] An insulating layer of Comparative Manufacturing Example 3 was manufactured in the same manner as the insulating layer of Manufacturing Example 1, except that the silicone resin and aerogel were mixed in a weight ratio of 30:70. However, padding of the silicone-aerogel composite was not achieved.

[0133]

[0134] Comparative Manufacturing Example 4: Manufacturing of Insulating Layer

[0135] Pure aerogel containing 100% aerogel without silicone resin was prepared. It was provided in powder form and was not padded.

[0136]

[0137] 2. Evaluation of thermal conductivity of insulation layers of manufacturing examples 1 to 4 and comparative manufacturing examples 1 to 4

[0138] For the insulation layers of Manufacturing Examples 1 to 4 and Comparative Manufacturing Examples 1 to 4 manufactured above, thermal conductivity was evaluated using the TPS method (ISO 2207-2). For Comparative Manufacturing Examples 2 to 4, which were not padded, thermal conductivity was measured in powder form.

[0139] Thermal conductivity (mW / m K) Padded or not Manufacturing example 1131.9O Manufacturing example 2107.2O Manufacturing example 381.9O Manufacturing example 474.5O Comparative Manufacturing example 1231O Comparative Manufacturing example 245X Comparative Manufacturing example 340.3X Comparative Manufacturing example 429.3X

[0140] Referring to Table 1 above, it can be confirmed that the insulation layers of Manufacturing Examples 1 to 4 have excellent insulation properties, as they exhibit sufficiently low thermal conductivity of about 150 mW / m·K or less, specifically, 131.9 mW / m·K or less. In particular, it was confirmed that the insulation layers of Manufacturing Examples 2 to 4 have even lower thermal conductivity of about 110 mW / m·K or less, specifically, 107.2 mW / m·K or less, and optimized insulation properties, as the aerogel content is 15 wt% or more.

[0141] In addition, it can be confirmed that the insulation layers of Manufacturing Examples 1 to 4 contain aerogel in an amount of 0.5 wt% to 40 wt%, or 10 wt% to 30 wt%, and silicone in an amount of 60 wt% to 99.5 wt%, or 70 wt% to 90 wt%, and thus have sufficient insulation performance and can be easily padded. In particular, it can be confirmed that the insulation layers of Manufacturing Examples 2 to 4 contain aerogel in an amount of 15 wt% to 30 wt%, and silicone in an amount of 70 wt% to 85 wt%, and thus have even better insulation performance and can be padded without deterioration in mechanical properties.

[0142] The insulation layer of Comparative Manufacturing Example 1 did not contain aerogel, so the thermal conductivity was very high and it is expected that it will be difficult to expect insulation performance.

[0143] The insulation layers of Comparative Manufacturing Examples 2 and 3 had low thermal conductivity when the aerogel content exceeded 40 wt%, but were not padded.

[0144] The insulation layer of Comparative Manufacturing Example 4 is 100% aerogel, has very low thermal conductivity, but exists in powder form and is not padded, so it cannot be applied as a fire-resistant pad.

[0145]

[0146] 3. Example: Manufacturing of a refractory pad

[0147] The insulating layer of Manufacturing Example 4 was used as the third layer, and a fire-resistant pad of the example was manufactured using the following method.

[0148] First, a blanket (thickness: 0.1 to 2 mm; non-combustible at ~1200°C under atmospheric pressure) containing commercially available ceramic wool (product name: Superwool plus, manufactured by Morgan) was used as a non-combustible layer (first layer).

[0149] Also, silicone resin (Dowsil from DOW) TM 7272), Dow Syl-off as a crosslinking agent TM 7028, Dow's Syl-off with Pt catalyst TM 4000 was mixed first. The mixture was mixed with sodium bicarbonate (NaHCO3), a flame retardant, at a weight ratio of 80:20.

[0150] The mixture on the dough thus manufactured was applied to one side of the insulating layer (third layer), and the non-combustible layer was laminated on the applied surface.

[0151] This laminated structure has a strength of 5 kgf / cm 2 By applying pressure and heat-treating at 75°C for 1 hour, the kneaded mixture was cured, forming a flame-retardant layer (second layer) between the insulating layer (third layer) and the non-combustible layer (first layer), and manufacturing a fire-resistant pad of the example.

[0152] For these refractory pads, the thermal conductivity was evaluated using the same method as in the above manufacturing example and comparative manufacturing example, and as a result, it was confirmed that they exhibited a low thermal conductivity of approximately 98.2 mW / m·K, and thus could effectively suppress heat transfer between unit cells within a secondary battery.

[0153]

[0154] 4. Evaluation of heat transfer inhibition characteristics of refractory pads

[0155] For the refractory pad of the above example, a 7.5 cm * 7.5 cm sample (thickness: 4.31 mm) was prepared. In addition, for comparison of thermal conductivity, a refractory pad (thickness: 4.06 mm) composed only of the insulating layer obtained in Manufacturing Example 4 was prepared as a sample of the same size and used as Comparative Example 1, and a pad (thickness: 4.4 mm) composed only of the non-combustible layer used in the above example was prepared as a sample of the same size and used as Comparative Example 2.

[0156] Using the device illustrated in Fig. 20, when a high temperature of 700°C was applied to the upper surface of each (refractory) pad while a pressure of 250 kPa was applied, the time required for the temperature of the lower surface of the refractory pad to rise from 40°C to 200°C was measured and evaluated. The results of this evaluation are shown in Table 2 below.

[0157] Example Comparative Example 1 Comparative Example 2 Thickness (mm) 4.3 14.06 4.4 Time to reach 200℃ (sec) 109.8 100.64 8.4

[0158] Referring to Table 2 above, it was confirmed that the fire-resistant pad of the example had superior heat conduction inhibition characteristics compared to the pads of Comparative Examples 1 and 2, and thus the time it took to reach 200°C was relatively long. This is because the laminated structure of the non-combustible layer (first layer), the flame-retardant layer (second layer), and the insulating layer (third layer) allows for more effective inhibition of high-temperature heat transfer through the interaction of the three layers. In particular, the carbonate-based flame retardant included in the flame-retardant layer (second layer) can generate water and carbon dioxide at about 80°C or higher, and its heat absorption action appears to assist in inhibiting heat transfer of the insulating layer and enhance the flame retardant effect.

[0159] Additionally, the refractory pad of the above embodiment is expected to exhibit superior mechanical properties compared to the refractory pad including only the insulation layer of Comparative Example 1, as the insulation layer (third layer) including the aerogel is laminated with other layers.

[0160]

[0161] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0162] [Explanation of symbols]

[0163] 1: Fireproof pad

[0164] 10: 1st floor

[0165] 20: Second floor

[0166] 30: Third floor

[0167] AG: Aerogel

[0168] SL: Silicone resin

Claims

1. A first layer containing a non-combustible material; A second layer comprising a carbonate flame retardant and a silicone resin; and A third layer comprising a silicone-aerogel composite including silicone resin and aerogel; The above silicone-aerogel composite is a refractory pad having an aerogel content of 0.5 wt% or more and 40 wt% or less based on the total weight of the third layer.

2. In paragraph 1, the silicone-aerogel composite is a refractory pad containing a silicone resin in an amount of 60 wt% or more and 99.5 wt% or less based on the total weight of the third layer.

3. In paragraph 1, the silicone-aerogel composite is a refractory pad containing aerogel in an amount of 15 wt% or more and 30 wt% or less based on the total weight of the third layer.

4. In paragraph 1, the flame retardant is a fireproof pad containing a carbonate of an alkali metal or alkaline earth metal.

5. In paragraph 1, the flame retardant is at least one selected from the group consisting of X2CO3 (X=Na, K, Rb, Cs), XHCO3 (X=Na, K, Rb, Cs), YCO3 (Y=Be, Mg, Ca, Sr, Ba), and Y(HCO3)2 (Y=Be, Mg, Ca, Sr, Ba). A fire-resistant pad.

6. In paragraph 1, the non-combustible material is a refractory pad containing an inorganic substance that does not combust at a temperature of 1000°C or lower under atmospheric pressure.

7. In paragraph 1, the fireproof pad is at least one selected from the group consisting of ceramic paper, ceramic wool, mica (mcia) sheet, and glass fiber.

8. In paragraph 1, a refractory pad laminated in the order of the first layer, the second layer, and the third layer.

9. In paragraph 1, a refractory pad laminated in the order of the second layer, the first layer, and the third layer.

10. In paragraph 1, a refractory pad laminated in the order of the first layer, the second layer, the third layer, the second layer, and the first layer.

11. In the first paragraph, a refractory pad laminated in the order of the second layer, the first layer, the third layer, the first layer, and the second layer.

12. In paragraph 1, a refractory pad laminated in the order of the first layer, the third layer, the second layer, the third layer, and the first layer.

13. In paragraph 1, A refractory pad laminated in the order of the second layer, the third layer, the first layer, the third layer, and the second layer.

14. In paragraph 1, a refractory pad in which the thickness of each of the first layer, the second layer, and the third layer is 0.1 mm or more and 5 mm or less.

15. A step of forming a first layer containing a non-combustible material; A step of forming a preliminary second layer comprising a carbonate flame retardant and a silicone resin; A step of forming a solid silicone-aerogel composite by mixing a liquid solvent-free silicone resin and aerogel particles, and forming a preliminary third layer including the silicone-aerogel composite; A step of laminating at least one of each of the first layer, the second preliminary layer, and the third preliminary layer; and A method for manufacturing a refractory pad, comprising: a step of curing the second preliminary layer and the third preliminary layer to form a second layer and a third layer, respectively.

16. In the step of curing the preliminary second layer and the preliminary third layer in the 15th paragraph to form the second layer and the third layer, respectively, A method for manufacturing a refractory pad by simultaneously curing the laminated second preliminary layer and the third preliminary layer.

17. In paragraph 15, a method for manufacturing a refractory pad, wherein the step of curing the second preliminary layer and the third preliminary layer to form the second layer and the third layer, respectively, is performed before the laminating step.

18. In the step of curing the preliminary second layer and the preliminary third layer in the 17th paragraph to form the second layer and the third layer, respectively, A method for manufacturing a refractory pad in which the second preliminary layer and the third preliminary layer are each cured at different times.

19. Multiple unit cells; and A secondary battery comprising a refractory pad according to any one of claims 1 to 14 formed between adjacent unit cells.

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