Acid-resistant flame-retardant thermal insulation material

Abstract

The invention belongs to the field of all-vanadium redox flow battery materials, and discloses an acid-resistant flame-retardant thermal insulation material. The film is formed by sequentially bonding an EVA (Ethylene Vinyl Acetate) acid-resistant film, a flame-retardant adhesive, rubber and plastic heat-insulating cotton and a flame-retardant adhesive. Compared with the prior art, the material has the advantages that the material cost is greatly reduced, the material is environment-friendly, the heat preservation effect on the vanadium battery system can be effectively achieved under most environmental conditions, the materials with different thicknesses can be selected to be adhered to the inner wall of the whole battery system according to the heat preservation and heat insulation requirements of the system, the material can be randomly cut, and the construction is simple, convenient and rapid.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of vanadium redox flow battery materials, and particularly relates to an acid-resistant, flame-retardant, heat-insulating material. BACKGROUND

[0002] Vanadium redox flow battery (VRFB) has a broad application prospect in the field of renewable energy grid connection and power grid peak regulation as a high-efficiency and large-scale energy storage electrochemical device. However, the electrolyte of the VRFB usually uses strong acid (such as sulfuric acid or mixed acid) as a supporting electrolyte, so that the internal system of the battery is in a strong acid environment (pH is usually lower than 2) for a long time, and the operating temperature range is relatively narrow (generally between 10-40℃). Therefore, the heat insulation performance of the system directly affects the efficiency, safety and service life of the battery.

[0003] At present, the industry mainly adopts the following schemes for the heat insulation problem of the VRFB system:

[0004] Scheme 1: Build peripheral heat insulation building

[0005] This scheme builds a closed heat insulation building outside the VRFB system, so that the heat insulation material is isolated from the acidic environment inside the battery system, and electric heating or air conditioning equipment is arranged inside the building to maintain the appropriate operating temperature. However, this scheme has the following significant defects:

[0006] High cost: The construction and maintenance of the heat insulation building and the operation of the heating equipment require additional investment of a large amount of funds, especially for large-scale energy storage power stations, which is economically poor.

[0007] Space limitation: The building structure greatly increases the land occupation of the system, which is not conducive to the high-density arrangement of the VRFB system, especially in cities or areas with limited land resources.

[0008] Energy consumption problem: The temperature is maintained by relying on active heating equipment, which has high energy consumption during long-term operation, which is contrary to the energy-saving and environmental protection concept of new energy storage.

[0009] Equipment corrosion risk: The heating equipment is easily corroded due to long-term exposure to the acidic atmosphere, which increases the failure rate and maintenance cost.

[0010] Scheme 2: Use polyurethane insulation board or insulation cloth

[0011] Some manufacturers try to directly lay polyurethane (PU) foam board or insulation cloth on the inner wall of the capacity unit box of the VRFB system to simplify the heat insulation structure. However, these two materials have serious deficiencies in practical application:

[0012] Limitations of polyurethane foam:

[0013] Poor acid resistance: Polyurethane is prone to hydrolysis and powdering in a strong acid environment, causing the insulation layer to fail quickly and even contaminating the electrolyte.

[0014] Flammability: Polyurethane is an organic polymer material that is extremely flammable when exposed to open flames or high temperatures. It also releases toxic gases when burning, posing a threat to the fire safety of the battery system.

[0015] Poor mechanical properties: The material is brittle and easily cracked under vibration or impact. After long-term use, the joints may leak.

[0016] Disadvantages of thermal insulation flannel:

[0017] Low insulation efficiency: The thermal conductivity of flannel is high, and its insulation effect is much lower than that of rigid foam materials, making it difficult to meet the insulation needs in low-temperature environments.

[0018] Poor structural stability: It is easy to deform and collapse after being squeezed, resulting in uneven thickness of the insulation layer and increased local heat loss.

[0019] Insufficient acid corrosion resistance: Ordinary flannel lacks acid resistance modification. Long-term contact with acid mist or droplets will cause fiber degradation and significantly shorten its lifespan.

[0020] Option 3: Rely on active heating and insulation

[0021] Some systems directly heat the electrolyte or the air in the box through a built-in electric heater or heat circulation device, but this method has the following problems:

[0022] Energy waste: Continuous consumption of electricity is required to maintain the temperature, and operating costs increase dramatically, especially in cold areas.

[0023] Low equipment reliability: Heating elements (such as metal heating tubes) are easily corroded in acidic environments, leading to short circuits or failures, and increasing maintenance difficulties.

[0024] Poor temperature uniformity: Local heating may cause temperature gradients inside the battery stack, affecting the performance consistency of the battery stack.

[0025] In summary, current thermal insulation solutions for all-vanadium flow battery systems have significant shortcomings: building insulation methods are costly and energy-inefficient; materials like polyurethane or flannel lack the necessary balance between acid resistance, flame retardancy, and thermal insulation; and active heating compromises system economics and reliability. Therefore, there is an urgent need to develop a new material that simultaneously meets the requirements of acid resistance, flame retardancy, high thermal insulation, and lightweight construction. Summary of the Invention

[0026] To overcome the shortcomings of the prior art, the present invention provides an acid-resistant, flame-retardant, heat-insulating material for use in a vanadium battery system in a box environment. This material provides acid resistance, heat preservation, and flame retardancy when the vanadium battery system is in operation.

[0027] The above-mentioned object of the present invention is achieved through the following technical scheme: an acid-resistant flame-retardant thermal insulation material, which is a film formed by sequentially bonding an EVA acid-resistant film, a flame-retardant adhesive, rubber-plastic thermal insulation cotton, and a flame-retardant adhesive, wherein the EVA acid-resistant film components include EVA resin, AC foaming agent, peroxide cross-linking agent, antioxidant, filler, and flame retardant, and the specific component ratio is: EVA resin 50-75wt%, AC foaming agent 2-5wt%, peroxide cross-linking agent 0.5-2wt%, antioxidant 0.1-0.3wt%, filler 5-10wt%, and flame retardant 25-55wt%.

[0028] Furthermore, the EVA resin component includes ethylene and vinyl acetate, wherein the ethylene content is 80 wt % and the vinyl acetate content is 20 wt %.

[0029] Furthermore, the AC foaming agent component in the EVA resin is C2H4O2N4, the peroxide crosslinking agent is DCP diisopropylbenzene peroxide, and the antioxidant component is C 73 H 108 O 12 The filler is CaCO3, and the flame retardant ingredients are ATH aluminum hydroxide and APP ammonium polyphosphate.

[0030] Furthermore, the rubber-plastic insulation cotton includes rubber, plastic, AC foaming agent, crosslinking agent, and flame retardant, and the specific composition ratio is: rubber 30-50wt%, plastic 20-40wt%, AC foaming agent 3-8wt%, crosslinking agent 0.5-2wt%, and flame retardant 20wt%.

[0031] Further preferably, the rubber component in the rubber-plastic thermal insulation cotton is one of NBR and CR, the plastic component is PVC, the AC foaming agent component is C2H4O2N4, the cross-linking agent is DCP dicumyl peroxide, and the flame retardant components are ATH aluminum hydroxide and APP ammonium polyphosphate.

[0032] Furthermore, the flame retardant adhesive is an acrylic adhesive or a polyurethane flame retardant adhesive.

[0033] Further preferably, the acrylate adhesive component comprises 70 wt% of an acrylate emulsion, 20 wt% of aluminum hydroxide, 8 wt% of terpene resin, 10 wt% of calcium carbonate, 1.5 wt% of aziridine, and 0.3 wt% of antifoaming agent; and the polyurethane flame-retardant glue component comprises 50 wt% of polyether polyol, 30 wt% of isocyanate, 15 wt% of magnesium hydroxide, 8 wt% of phosphate ester, and 1 wt% of glass fiber.

[0034] The preparation method of the EVA acid-resistant film comprises the following steps:

[0035] 1. Raw material mixing and melting: uniformly mix EVA resin base material, crosslinking agent, filler, antioxidant, flame retardant, lubricant, and color master batch, and melt through a screw extruder, with a melting temperature of 120-160 DEG C;

[0036] 2. Injection of foaming agent: directly mix AC foaming agent into the raw materials;

[0037] 3. Foaming and shaping: extrude the solution through a slit die, instantaneously foam after pressure release, and roll into a sheet through a multi-roller calender;

[0038] 4. Slitting and winding.

[0039] The preparation method of the rubber-plastic thermal insulation cotton comprises the following steps:

[0040] 1. Raw material pretreatment (mixing): uniformly mix rubber (NBR) and plastic (PVC), DOP plasticizer, and stabilizer in a mixer (120-140 DEG C), and then add AC foaming agent (C2H4O2N4), crosslinking agent (DCP peroxide diisopropylbenzene), and flame retardant (ATH aluminum hydroxide+APP ammonium polyphosphate) when the temperature drops to below 80 DEG C;

[0041] 2. Extrusion and foaming: melt through a double-screw extruder (temperature partition control: 160-180 DEG C), inject a physical foaming agent into the melt, extrude the melt through a wide die (1-2 m), instantaneously foam after pressure release, and form closed-cell foam;

[0042] 3. Shaping and cooling: shape the foam through a three-roller calender (temperature 60-80 DEG C) to a thickness of 5-50 mm, and water-cool and solidify;

[0043] 4. Post-treatment: slitting and winding or directly surface-coating (EVA acid-resistant film).

[0044] The preparation method of the flame-retardant adhesive comprises the following steps:

[0045] 1. Preliminary pretreatment of base material: perform corona treatment on the surface of the rubber-plastic thermal insulation cotton;

[0046] 2. Adhesive coating: using flame-retardant adhesive-acrylate adhesive, coated on the surface of the rubber plastic insulation cotton;

[0047] 3. Hot pressing composite: using the above-mentioned EVA acid-resistant film and rubber plastic insulation cotton through hot pressing roller (temperature 100-150℃, pressure 0.3-0.8MPa) composite, cooling roller rapid shaping (20-40℃);

[0048] 4. Self-adhesive film: the back of the rubber plastic insulation cotton is pre-coated with acrylate adhesive, and is covered with release paper, which can be torn and pasted during construction.

[0049] 5. Rolling and slitting: automatic deviation correction, slitting into the required width (commonly 1m / 1.2m).

[0050] The beneficial effects of the present application compared with the prior art are:

[0051] 1. The material cost is greatly reduced compared with the past scheme, which is friendly to the environment and can effectively play a role in insulating the vanadium battery system under most environmental conditions.

[0052] 2. Different thicknesses of the material can be selected and pasted to the inner wall of the entire battery system according to the system insulation and heat insulation requirements, and the material can be cut at will, and the construction is simple and fast.

[0053] 3. The material has strong acid resistance and can meet the long-term use in the acid electrolyte of the all-vanadium redox flow battery, and does not corrode and denature, which can ensure a reliable and stable operating environment for the battery system.

[0054] 4. The EVA film on the surface of the acid-resistant flame-retardant insulation and heat insulation material has high strength, good toughness and other excellent properties. BRIEF DESCRIPTION OF DRAWINGS

[0055] The present application will be further described below in conjunction with the drawings and specific embodiments

[0056] Figure 1 is a structural schematic diagram of the acid-resistant flame-retardant insulation and heat insulation material of the present application;

[0057] Figure 2 is a comparison chart of the corrosion resistance test results of the acid-resistant flame-retardant insulation and heat insulation material of the present application.

[0058] In the figure, 1. EVA acid-resistant film; 2. Flame-retardant adhesive; 3. Rubber plastic insulation cotton. DETAILED DESCRIPTION

[0059] The present application will be further described below in conjunction with the drawings and specific embodiments

[0060] Example 1

[0061] An acid-resistant flame-retardant thermal insulation material, which is made of EVA acid-resistant film, flame-retardant adhesive, rubber-plastic thermal insulation cotton, and adhesive. Figure 1 The detailed process is as follows: the rubber-plastic thermal insulation cotton material is used as the base layer, adhesive is applied to the upper surface of the rubber-plastic thermal insulation cotton layer, and a 2mm EVA film is covered on it, which is pressed and bonded by equipment, and adhesive is pasted on the lower part of the rubber-plastic thermal insulation cotton to form a multi-material composite thermal insulation material.

[0062] The surface EVA acid-resistant film of the above-mentioned acid-resistant flame-retardant thermal insulation material is mainly composed of an EVA resin base material, namely: ethylene (Ethylene)-vinyl acetate (VA) copolymer. According to specific performance requirements, various functional additives are added and mixed and foamed. The specific composition is as follows (weight percentage): EVA resin (VA 20%) 50-75%, AC foaming agent (C2H4O2N4) 2-5%, peroxide (DCP diisopropylbenzene peroxide) crosslinking agent 0.5-2%, antioxidant 1010 (C 73 H 108 O 12 )0.1-0.3, filler (CaCO3) 5-10, flame retardant (ATH aluminum hydroxide + APP ammonium polyphosphate) 25-55, flame retardant grade B1 (GB8624);

[0063] The above EVA acid-resistant film adopts continuous extrusion foaming molding process. The specific preparation process is as follows:

[0064] Step 1: Mix and melt the raw materials: EVA resin base material + cross-linking agent + filler + antioxidant + flame retardant + lubricant + masterbatch are evenly mixed and melted through a screw extruder (120-160℃);

[0065] Step 2: Injecting the foaming agent: Mix the AC foaming agent directly into the raw materials;

[0066] Step 3: Foaming and shaping: The melt is extruded through a slit die, foams instantly after the pressure is released, and is cooled and rolled into a sheet by a multi-roll calender;

[0067] Step 4: Slitting and rolling.

[0068] The base layer of the above-mentioned acid-resistant flame-retardant thermal insulation material - rubber-plastic thermal insulation cotton, is a flexible closed-cell foam insulation material widely used in construction, HVAC (heating, ventilation and air conditioning), refrigeration, industrial equipment and other fields. It is mainly made of rubber (such as nitrile rubber) and plastic (polyurethane PVC) and other functional additives, mixed and foamed; its specific material composition is as follows (weight %): rubber (NBR / CR) 30-50, plastic (PVC) 20-40, AC foaming agent (C2H4O2N4) 3-8, cross-linking agent (DCP diisopropyl peroxide) 0.5-2, flame retardant (ATH aluminum hydroxide + APP ammonium polyphosphate) 20, flame retardant grade B1 (GB 8624), DOP plasticizer (C 24 H 38 O4) 5-15, stabilizer (lead salt / organic tin) 1-3;

[0069] The above rubber-plastic thermal insulation cotton adopts the continuous extrusion foaming molding process. The specific process flow is as follows:

[0070] Step 1: Raw material pretreatment (mixing): Rubber (NBR) and plastic (PVC), DOP plasticizer, stabilizer, etc. are mixed together (120-140°C). When the temperature drops below 80°C, AC foaming agent (C2H4O2N4), crosslinking agent (DCP diisopropylbenzene peroxide), and flame retardant (ATH aluminum hydroxide + APP ammonium polyphosphate) are added.

[0071] Step 2: Extrusion foaming: The material is melted through a twin-screw extruder (temperature zone control: 160-180°C), a physical foaming agent is injected into the melt, and the melt is extruded through a wide die (1-2m). After the pressure is released, it foams instantly to form closed-cell foam.

[0072] Step 3: Shaping and cooling: The foam passes through a three-roll calender (temperature 60-80°C) to set the thickness (5-50mm), and then is water-cooled and solidified;

[0073] Step 4, post-processing: slitting and rewinding or direct surface coating (EVA acid-resistant film)

[0074] The flame retardant adhesive of the above-mentioned acid-resistant flame retardant thermal insulation material is an acrylic adhesive or a polyurethane (PU) flame retardant adhesive. The main ingredients of the acrylic adhesive are: acrylic emulsion, aluminum hydroxide (ATH), terpene resin, calcium carbonate, crosslinking agent (aziridine), defoaming agent, and the flame retardant grade is B1 (GB 8624); the main ingredients of the polyurethane (PU) flame retardant adhesive are: polyether polyol, PMDI curing agent (isocyanate), MDH (magnesium hydroxide), TCPP (phosphate ester), glass fiber

[0075] The above acid-resistant flame-retardant thermal insulation material adopts the flame-retardant adhesive hot pressing composite process, and the specific process is as follows:

[0076] Step 1: Pre-treatment of substrate: corona treatment on the surface of rubber-plastic insulation cotton;

[0077] Step 2: Adhesive coating: Use flame retardant adhesive - acrylic adhesive to coat the surface of rubber-plastic insulation cotton;

[0078] Step 3, hot pressing composite: use the above EVA acid-resistant film and rubber-plastic insulation cotton to composite through hot pressing rollers (temperature 100-150°C, pressure 0.3-0.8MPa), and quickly set with cooling rollers (20-40°C);

[0079] Step 4: Self-adhesive lamination: Pre-coat acrylic adhesive on the back of the rubber-plastic insulation cotton and cover it with release paper. Just peel it off during construction.

[0080] Step 5, winding and slitting: automatic deviation correction, slitting to the required width (commonly 1m / 1.2m).

[0081] The acid-resistant flame-retardant thermal insulation material prepared from the above-mentioned acid-resistant flame-retardant thermal insulation material was subjected to performance testing, and the specific results are as follows:

[0082]

[0083]

[0084] (Corrosion resistance test see Figure 2 )

[0085] From the above results, it can be seen that the acid-resistant flame-retardant thermal insulation material provided by the present invention has anti-corrosion and acid-resistant properties, B1 flame retardancy, and thermal conductivity reaches below 0.038W / m·K. In addition to the parameter characteristics of the two materials themselves, the acid-resistant flame-retardant thermal insulation material not only has the characteristics of acid resistance, flame retardancy, and thermal insulation, but also has the characteristics of moisture-proof and waterproof, soft and easy to construct, weather-resistant and durable, environmentally friendly and safe.

[0086] The all-vanadium liquid flow battery system can be covered with different thicknesses of this material on the outside of the storage tank, the outside of the pipeline and the inner wall of the container according to the insulation requirements to achieve thermal insulation within the system.

[0087] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. An acid-resistant, flame-retardant, thermal insulation material, characterized in that: The film is formed by sequentially bonding an EVA acid-resistant film, a flame-retardant adhesive, rubber-plastic thermal insulation cotton, and the flame-retardant adhesive. The components of the EVA acid-resistant film include EVA resin, AC foaming agent, peroxide cross-linking agent, antioxidant, filler, and flame retardant. The specific component ratio is: EVA resin 50-75wt%, AC foaming agent 2-5wt%, peroxide cross-linking agent 0.5-2wt%, antioxidant 0.1-0.3wt%, filler 5-10wt%, and flame retardant 25-55wt%.

2. The acid-resistant, flame-retardant, thermal insulation material according to claim 1, characterized in that: The EVA resin component includes ethylene and vinyl acetate, wherein the ethylene content is 80 wt % and the vinyl acetate content is 20 wt %.

3. The acid-resistant, flame-retardant, thermal insulation material according to claim 1, characterized in that: The AC foaming agent component in the EVA resin is C2H4O2N4, the peroxide crosslinking agent is DCP diisopropylbenzene peroxide, and the antioxidant component is C 73 H 108 O 12 The filler is CaCO3, and the flame retardant ingredients are ATH aluminum hydroxide and APP ammonium polyphosphate.

4. The acid-resistant flame-retardant thermal insulation material according to claim 1, characterized in that: The rubber-plastic thermal insulation cotton comprises rubber, plastic, AC foaming agent, crosslinking agent and flame retardant, and the specific composition ratio is: rubber 30-50wt%, plastic 20-40wt%, AC foaming agent 3-8wt%, crosslinking agent 0.5-2wt% and flame retardant 20wt%.

5. The acid-resistant, flame-retardant, thermal insulation material according to claim 4, characterized in that: The rubber component of the rubber-plastic thermal insulation cotton is one of NBR and CR, the plastic component is PVC, the AC foaming agent component is C2H4O2N4, the cross-linking agent is DCP diisopropylbenzene peroxide, and the flame retardant components are ATH aluminum hydroxide and APP ammonium polyphosphate.

6. The acid-resistant, flame-retardant, thermal insulation material according to claim 1, characterized in that: The flame retardant adhesive is an acrylic adhesive or a polyurethane flame retardant adhesive.

7. The acid-resistant, flame-retardant, thermal insulation material according to claim 6, characterized in that: The acrylic adhesive comprises 70 wt% of acrylic emulsion, 20 wt% of aluminum hydroxide, 8 wt% of terpene resin, 10 wt% of calcium carbonate, 1.5 wt% of aziridine, and 0.3 wt% of defoaming agent; the polyurethane flame retardant adhesive comprises 50 wt% of polyether polyol, 30 wt% of isocyanate, 15 wt% of magnesium hydroxide, 8 wt% of phosphate, and 1 wt% of glass fiber.

8. The method for preparing the EVA acid-resistant film according to claim 1, wherein The continuous extrusion foaming molding process is adopted, and the specific preparation steps are: S1. Raw material mixing and melting: EVA resin base material + crosslinking agent + filler + antioxidant + flame retardant + lubricant + masterbatch are mixed evenly and melted through a screw extruder at a melting temperature between 120-160°C; S2. Injection of foaming agent: Mix the AC foaming agent directly into the raw material; S3 foaming shaping: the melt is extruded through a slit die, foams instantly after pressure release, and is cooled and rolled into a sheet by a multi-roll calender; S4. Slitting and winding.

9. The method for preparing the rubber-plastic thermal insulation cotton according to claim 1, wherein: The continuous extrusion foaming molding process is adopted, and the specific preparation steps are: S1. Raw material pretreatment: Rubber and plastic, DOP plasticizer, and stabilizer are mixed at 120-140°C. When the temperature drops below 80°C, AC foaming agent, crosslinking agent, and flame retardant are added. S2. Extrusion foaming: The melt is melted through a twin-screw extruder, where the temperature is controlled in zones of 160-180°C. A physical foaming agent is injected into the melt, which is then extruded through a 1-2m wide die. After the pressure is released, the melt foams instantly to form closed-cell foam. S3 shaping cooling: The foam is shaped at 60-80 by a three-roll calender with a thickness of 5-50mm and water-cooled; S4. Post-processing: slitting and rewinding or directly covering the surface with EVA acid-resistant film.

10. The method for preparing a flame retardant adhesive according to claim 1, wherein: The hot pressing composite process is adopted, and the specific preparation steps are: S1. Pre-treatment of substrate: corona treatment on the surface of rubber and plastic insulation cotton; S2. Adhesive coating: Use flame retardant adhesive - acrylic adhesive, and apply it on the surface of rubber-plastic insulation cotton; S3 hot pressing composite: using the above EVA acid-resistant film and rubber insulation cotton temperature 100-150 ℃, pressure 0.3-0.8MPa by hot pressing roller composite, 20-40 ℃ cooling roller rapid shaping; S4. Self-adhesive lamination: The back of the rubber-plastic thermal insulation cotton is pre-coated with acrylic adhesive and covered with release paper. It can be peeled off and pasted during construction. S5. Winding and slitting: Automatically correct the deviation and slit to the required width.

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