A thermal insulation composite material, its preparation method, and a cover plate comprising the thermal insulation composite material.

Abstract

This invention discloses a thermal insulation composite material, its preparation method, and a cover plate comprising the thermal insulation composite material. The thermal insulation composite material comprises reinforcing fibers and a molding agent coated on the surface of the reinforcing fibers. The reinforcing fibers comprise 0-74 wt% continuous phase reinforcing fibers and 26-100 wt% discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers. The molding agent passes the UL 94V0 flame retardancy test. The thermal insulation composite material of this invention does not burn through after being burned at 1000°C or 1300°C for 30 minutes, exhibiting excellent thermal insulation and fire resistance properties.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a thermal insulation composite material, a method for preparing the thermal insulation composite material, a cover plate and a lower tray comprising the thermal insulation composite material, and a battery module comprising the cover plate and / or the lower tray. Background Technology

[0002] With the increasing popularity of new energy vehicles, the number of fires involving these vehicles has also increased significantly. These fires mainly occur in two ways: First, during traffic accidents, the battery of a new energy vehicle is impacted and compressed, disrupting its internal stability and leading to a fire. Since the batteries in new energy vehicles often have large capacities, such accidents can be extremely dangerous. Second, new energy vehicles spontaneously combust while parked or charging. The battery is the core component responsible for fires in new energy vehicles and is an area requiring close monitoring.

[0003] The battery module consists of a top cover and a lower housing, which together form the battery housing, where the battery is secured. When the battery catches fire, the top cover is burned through by the high-temperature flames, and the flames quickly spread outside the battery housing, endangering the safety of the occupants of the vehicle.

[0004] To mitigate the risk of thermal runaway in new energy vehicles, some manufacturers are considering installing thermal insulation pads between batteries. This prevents a cascading failure of the remaining batteries if one battery experiences thermal runaway. For example, a new energy vehicle battery thermal insulation pad disclosed in application number 202121332706.X has buffer materials placed on both sides of the thermal insulation core material, adhesive encapsulating film covering the top and bottom of both the thermal insulation core material and the buffer materials, and self-adhesive encapsulating film wrapping the front and rear sides of the thermal insulation core material. The self-adhesive encapsulating film wrapping the sides of the thermal insulation core material where no buffer material is present, while the buffer material is only placed on the sides of the thermal insulation core material, significantly increases the effective area of ​​the thermal insulation core material. This results in a larger thermal insulation and flame-retardant area between the new energy battery cells, delaying the time of module thermal runaway. For example, application number 202210273551.X discloses a low thermal conductivity mica composite for thermal runaway protection between battery cells. This component uses an 8mm thick porous insulating material layer as the core layer, with composite mica sheets laminated to the upper and lower surfaces of the porous insulating material layer. Reinforcing mesh fabric is then hot-pressed onto the surface of the composite mica sheets. By using this low thermal conductivity mica composite between the battery cells, good thermal runaway protection performance can be ensured, thereby improving the safety of new energy vehicle batteries.

[0005] Placing thermal insulation pads or materials between battery cells provides a certain degree of protection against thermal runaway. However, the limited space in the battery pack itself means that the thickness of the thermal insulation pads or materials cannot be too large. In addition, when one battery experiences thermal runaway, the insulation pad alone can only delay the runaway time and cannot prevent the chain reaction of runaway from adjacent batteries, still posing a danger to the safety of people and property in the surrounding area.

[0006] When a battery experiences thermal runaway, electrolyte and toxic gases are ejected from the battery pack's top cover. Optimizing the thermal insulation performance of the battery pack's top cover to prevent it from burning through and to contain the flames within the battery pack would significantly reduce personal injury and property damage. Existing technologies disclose injection-molded parts based on polypropylene or polyamide as battery pack top covers; however, injection molding of polypropylene or polyamide requires high processing costs, high injection pressure, and high temperatures, making industrialization difficult. Summary of the Invention

[0007] In view of the aforementioned deficiencies of the prior art, the present invention provides a thermally insulating composite material with excellent thermal insulation performance. Using this thermally insulating composite material in a battery cover can significantly reduce the risk of combustion flames spreading outside the battery pack. To this end, the present invention also provides a method for preparing the thermally insulating composite material. Furthermore, the present invention also provides a cover and a lower tray comprising the thermally insulating composite material, and a battery module comprising the cover and / or the lower tray.

[0008] To address the aforementioned technical problems, a first aspect of the present invention provides a thermal insulation composite material comprising reinforcing fibers and a molding agent coated on the surface of the reinforcing fibers, wherein the reinforcing fibers comprise 0-74 wt% of continuous phase reinforcing fibers and 26-100 wt% of discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers; and the molding agent passes a UL 94V0 level flame retardant performance test.

[0009] In a preferred embodiment, the reinforcing fiber comprises 0-65% by weight of the reinforcing fiber in the form of a continuous phase and 35-100% by weight of the reinforcing fiber in the form of a discontinuous phase, based on the total weight of the reinforcing fiber.

[0010] In a preferred embodiment, the reinforcing fiber comprises 0-45% by weight of a continuous phase reinforcing fiber and 55-100% by weight of a discontinuous phase reinforcing fiber, based on the total weight of the reinforcing fiber.

[0011] As a more preferred embodiment, the reinforcing fiber comprises 100% by weight of the reinforcing fiber in the form of a discontinuous phase.

[0012] As a more preferred embodiment, the reinforcing fiber comprises 45% by weight of the reinforcing fiber in the form of a continuous phase and 55% by weight of the reinforcing fiber in the form of a discontinuous phase.

[0013] In a preferred embodiment, the reinforcing fiber is selected from any one or a mixture of glass fiber, ceramic fiber, aramid fiber, carbon fiber, basalt fiber, and natural fiber.

[0014] In a preferred embodiment, the SiO2 content in the glass fiber is higher than 50%.

[0015] In a more preferred embodiment, the glass fiber contains more than 95% SiO2.

[0016] In a more preferred embodiment, the glass fiber is a high-silica fiber.

[0017] In a preferred embodiment, the continuous phase reinforcing fiber is a pad, a woven fabric, or a combination thereof.

[0018] In a preferred embodiment, the discontinuous phase reinforcing fiber is obtained by in-situ short-cutting of long fibers.

[0019] In a preferred embodiment, the length of the discontinuous phase reinforcing fiber is 3-100 mm.

[0020] In a preferred embodiment, the molding agent is an inorganic molding agent or an organic molding agent.

[0021] In a preferred embodiment, the molding agent is selected from inorganic molding agents or organic molding agents.

[0022] In a more preferred embodiment, the inorganic molding agent is selected from any one of phosphate, silicate, sulfate, and borate molding agents.

[0023] In a more preferred embodiment, the molding agent is selected from any one of unsaturated resin, polyurethane, or polypropylene molding agents.

[0024] In a preferred embodiment, the weight ratio of the reinforcing fiber to the molding agent is ≤1:0.25.

[0025] In a preferred embodiment, the weight ratio of the reinforcing fiber to the molding agent is 1:0.25-1:2.5.

[0026] In a preferred embodiment, the thermal insulation composite material is a sheet with a thickness of ≥0.2mm.

[0027] In a preferred embodiment, the thermal insulation composite material is a sheet with a thickness of ≥0.5mm.

[0028] In a preferred embodiment, the thermal insulation composite material is a sheet with a thickness of 0.2 mm to 3 mm.

[0029] In a preferred embodiment, the thermal insulation composite material is a sheet with a thickness of 0.5 mm to 3 mm.

[0030] In a more preferred embodiment, the thickness of the thermal insulation composite material is 0.5mm-2mm.

[0031] A second aspect of the present invention provides a method for preparing the above-mentioned thermal insulation composite material.

[0032] S1. Lay up continuous phase reinforcing fibers and discontinuous phase reinforcing fibers to form a reinforcing fiber layer;

[0033] S2. Spray or inject the molding agent onto the reinforcing fiber layer;

[0034] S3. Hot pressing in a mold to obtain the sprayed or injected product, thus obtaining the heat-insulating composite material.

[0035] In a preferred embodiment, in step S1, the continuous phase reinforcing fibers and the discontinuous phase reinforcing fibers are laid alternately or continuously.

[0036] In a preferred embodiment, step S2 involves spraying or injecting a molding agent onto one or both sides of the reinforcing fiber layer.

[0037] In a third aspect, the present invention provides a cover plate comprising the above-described heat-insulating composite material or the heat-insulating composite material prepared by the above-described method.

[0038] In a preferred embodiment, the cover plate also includes at least one metal sheet located on at least one side of the thermal insulation composite material.

[0039] In a preferred embodiment, the cover plate has at least one metal sheet on each side of the thermal insulation composite material.

[0040] In a preferred embodiment, the heat-insulating composite material in the cover plate consists of two layers, located on both sides of the metal sheet.

[0041] In a preferred embodiment, the metal sheet in the cover plate is approximately the same size as the thermal insulation composite material.

[0042] In a preferred embodiment, the size of the metal sheet in the cover is smaller than the size of the thermal insulation composite material.

[0043] As a more preferred embodiment, the cover plate also includes at least one heat insulation layer.

[0044] In a more preferred embodiment, the material of the heat insulation layer is selected from any one of calcium hydroxide, magnesium hydroxide, aluminum hydroxide, or expandable graphite.

[0045] In a more preferred embodiment, the thermal insulation composite material consists of two layers, located on both sides of the thermal insulation layer.

[0046] As a more preferred embodiment, at least one metal sheet is disposed between the heat-insulating composite material and the heat-insulating layer in the cover plate.

[0047] In a more preferred embodiment, the metal sheet is made of aluminum alloy, iron, steel, or aluminum sheet.

[0048] A fourth aspect of the present invention provides a lower tray for a battery module, the lower tray comprising the above-described heat-insulating composite material or the heat-insulating composite material prepared by the above-described method.

[0049] In a fifth aspect, the present invention provides a battery module comprising an energy storage battery cell, and further comprising the aforementioned cover plate and / or the aforementioned lower tray, wherein the cover plate is located above or on both sides of the energy storage battery cell, and the lower tray is located below the energy storage battery cell.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] (1) The heat insulation composite material of the present invention will not be burned through after being burned at 1000℃ or 1300℃ for 15min-30min, and has excellent heat insulation and fire resistance.

[0052] (2) The heat-insulating composite material of the present invention is used as a battery cover plate. When the actual cell explosion test is carried out, the cover plate is not burned through, which reduces the risk of flames escaping and endangering personal safety during battery combustion and has excellent safety performance.

[0053] (3) The thermal insulation composite material of the present invention can be made into a thickness of 2 mm or less, and no burn-through phenomenon occurs when it is burned at 1000℃ or 1300℃ for 15 min-30 min. It still has excellent thermal insulation and fire resistance performance with a small thickness, which meets the current demand for lightweighting.

[0054] (4) The thermal insulation composite material of the present invention can replace mica and does not have the problem of cleanliness, making it suitable for widespread promotion.

[0055] (5) The raw materials of the thermal insulation composite material of the present invention are readily available and the process is simple, which reduces the production cost.

[0056] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0057] Figure 1 These are comparison images of the heat-insulating composite material prepared in Example 1 before and after high-temperature calcination, where A represents before calcination and B represents after calcination.

[0058] Figure 2 This is a temperature change graph of the thermal insulation composite material prepared in Example 1 during high-temperature burning (vertical axis is the temperature of the thermocouple on the back surface of the sample, and horizontal axis is time).

[0059] Figure 3 These are comparison images of the heat-insulating composite material prepared in Example 2 before and after high-temperature calcination, where A represents before calcination and B represents after calcination.

[0060] Figure 4 This is a temperature change graph of the thermal insulation composite material prepared in Example 2 during high-temperature burning (vertical axis is the temperature of the thermocouple on the back surface of the sample, and horizontal axis is time).

[0061] Figure 5 These are comparison images of the thermal insulation composite material prepared in Comparative Example 1 before and after high-temperature calcination, where A represents before calcination and B represents after calcination.

[0062] Figure 6 This is a graph showing the temperature change of the thermal insulation composite material prepared in Example 1 during high-temperature burning (the vertical axis represents the temperature of the thermocouple on the back surface of the sample, and the horizontal axis represents time).

[0063] Figure 7 These are comparison images of the heat-insulating composite material prepared in Example 6 before and after high-temperature calcination, where A represents before calcination and B represents after calcination.

[0064] Figure 8 This is a temperature change graph of the thermal insulation composite material prepared in Example 6 during high-temperature burning;

[0065] Figure 9 These are comparison images of the heat-insulating composite material prepared in Example 7 before and after high-temperature calcination, where A represents before calcination and B represents after calcination.

[0066] Figure 10 This is a temperature change graph of the thermal insulation composite material prepared in Example 7 during high-temperature burning;

[0067] Figure 11 These are comparison images of the heat-insulating composite material prepared in Example 13 before and after high-temperature calcination, where A represents before calcination and B represents after calcination;

[0068] Figure 12 This is a temperature change graph of the thermal insulation composite material prepared in Example 13 during high-temperature burning;

[0069] Figure 13 This is a schematic diagram showing the location of the temperature sensor installed on the back of the thermal insulation composite material during fire resistance performance testing.

[0070] Figure 14 This is a schematic diagram showing the location of the temperature sensor installed at the flame during fire resistance performance testing.

[0071] Figure 15 This is a graph showing the temperature changes of the thermal insulation composite material prepared in Example 5 during the burning process, as measured by various temperature sensors.

[0072] Figure 16 This is a diagram of the back side of the heat-insulating composite material prepared in Example 5 after high-temperature burning;

[0073] Figure 17 This is a graph showing the temperature changes of the thermal insulation composite material prepared in Example 8 during the burning process, as measured by various temperature sensors.

[0074] Figure 18 This is a diagram of the back side of the heat-insulating composite material prepared in Example 8 after high-temperature burning;

[0075] Figure 19 This is a graph showing the temperature changes of the thermal insulation composite material prepared in Example 9 during the burning process, as measured by various temperature sensors.

[0076] Figure 20 This is a diagram of the back side of the heat-insulating composite material prepared in Example 9 after high-temperature burning;

[0077] Figure 21 This is a graph showing the temperature changes of the thermal insulation composite material prepared in Example 10 during the burning process, as measured by various temperature sensors.

[0078] Figure 22 This is a diagram of the back side of the heat-insulating composite material prepared in Example 10 after high-temperature burning;

[0079] Figure 23 This is a schematic diagram of the installation of various components in the battery cell explosion experiment;

[0080] Figure 24 This is a schematic diagram showing the location of the thermal insulation composite material in the battery cell explosion experiment;

[0081] Figure 25 This is a temperature change diagram on the back of the thermal insulation composite material during a battery cell explosion experiment;

[0082] Figure 26 This is a diagram of the back of the thermal insulation composite material after the battery cell explosion test;

[0083] Figure 27 This is a schematic diagram of the cell arrangement in a real cell explosion experiment.

[0084] Among them: 1-1 temperature sensor, 2-2 temperature sensor, 3-3 temperature sensor, 4-4 temperature sensor, 5-5 temperature sensor, 6-6 temperature sensor, 7-thermal insulation composite material, 8-back temperature sensor, 9-cell voltage measurement point, 10-cell burst temperature sensor, 11-heating element. Detailed Implementation

[0085] To make the technical means, inventive features, objectives, and effects of the invention readily understandable, the invention is further illustrated below with reference to specific figures. However, the invention is not limited to the embodiments described below.

[0086] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0087] As the core energy device with the largest mass (≥30%) and highest cost (40%-60%) in a new energy vehicle, the power battery pack needs continuous weight reduction to improve the vehicle's power and range. However, at the same time, the power battery pack faces the challenge of battery thermal runaway and the resulting safety issues related to personal injury and property. With the increasing market share of new energy vehicles, battery spontaneous combustion and fires are becoming more frequent. To address this issue, some manufacturers are considering installing heat insulation layers between batteries to prevent thermal runaway in one battery from causing other batteries to follow suit. However, this only delays the onset of thermal runaway and cannot completely prevent the threat to the safety of people inside and around the vehicle caused by battery thermal runaway.

[0088] When a battery pack experiences thermal runaway, the electrolyte and toxic gases are ejected from the battery pack cover. If the heat insulation performance of the cover can be improved so that it is not burned through when exposed to high temperatures, the flames cannot escape from the battery pack. In the event of a fire or spontaneous combustion of the battery pack, the loss can be contained within the battery pack, reducing casualties.

[0089] Based on this, this application repeatedly screens and tests the materials used in the cover plate to obtain a heat-insulating composite material.

[0090] This application provides a thermal insulation composite material comprising reinforcing fibers and a molding agent coated on the surface of the reinforcing fibers, wherein the reinforcing fibers comprise 0-74% by weight of continuous phase reinforcing fibers and 26-100% by weight of discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers.

[0091] Reinforcing fibers are commonly used fibrous reinforcing materials. There are many types of reinforcing fibers, which can be broadly classified into two categories based on their chemical composition: inorganic fibers and organic fibers. Organic fibers include synthetic fibers and natural fibers. Synthetic fibers include aramid fibers, orylon fibers, polyester fibers, nylon fibers, vinylon fibers, polypropylene fibers, and polyimide fibers; natural fibers include cotton fibers and sisal fibers; inorganic fibers include glass fibers, carbon fibers, boron fibers, and metal fibers.

[0092] Reinforcing fibers are further divided into continuous-phase and discontinuous-phase reinforcing fibers. Continuous-phase reinforcing fibers refer to fibers in a reinforcing fiber layer that are combined or connected to form a monolithic layer. Discontinuous-phase reinforcing fibers refer to fibers that are not connected to each other or are not monolithic. Based on size, reinforcing fibers are also divided into long fibers and short fibers. Long fibers have a particle length between 12mm and 25mm, while short fibers typically have a particle length ≤3mm. Discontinuous-phase reinforcing fibers consist of multiple short fibers arranged randomly, such as in needle-punched felt, where short fibers are obtained by in-situ stub-cutting long fibers. The length of discontinuous-phase reinforcing fibers is 3-100mm. Continuous-phase reinforcing fibers, on the other hand, consist of multiple short or long fibers arranged in an orderly manner to form a whole, such as in a solid woven fabric.

[0093] Based on the total weight of the reinforcing fibers, the reinforcing fibers in this application comprise 0-74 wt% of continuous phase reinforcing fibers and 26-100 wt% of discontinuous phase reinforcing fibers. Preferably, they comprise 0-65 wt% of continuous phase reinforcing fibers and 35-100 wt% of discontinuous phase reinforcing fibers. More preferably, they comprise 0-45 wt% of continuous phase reinforcing fibers and 55-100 wt% of discontinuous phase reinforcing fibers.

[0094] During the raw material proportioning process, repeated experiments revealed that the proportion of discontinuous phase reinforcing fibers directly affects the thermal insulation performance of the composite material; a higher proportion of discontinuous phase reinforcing fibers results in superior thermal insulation performance. The weight of discontinuous phase reinforcing fibers can be 100%, at which point the weight of continuous phase reinforcing fibers is 0. Of course, the weight of discontinuous phase reinforcing fibers can be reduced, but it must not be less than 26%, otherwise the thermal insulation performance of the composite material will be affected. When the weight of discontinuous phase reinforcing fibers is 26%, the weight of continuous phase reinforcing fibers is 74%.

[0095] Based on the above ratio of continuous phase and discontinuous phase reinforcing fibers, the selection of reinforcing fibers is quite diverse, such as glass fiber, basalt fiber, carbon fiber, natural fiber, aramid fiber, ceramic fiber, etc., which can be added individually or in combination. Glass fiber or a composite of glass fiber and other reinforcing fibers is preferred; more preferably, glass fiber with a SiO2 content of more than 50% or a composite of glass fiber with a SiO2 content of more than 50% and other reinforcing fibers is preferred; even more preferred is glass fiber with a SiO2 content of more than 95% or a composite of glass fiber with a SiO2 content of more than 95% and other reinforcing fibers is preferred.

[0096] High-silica fiber is a high-purity glass fiber with a SiO2 content of over 96%, exhibiting excellent ablation resistance. High-silica fiber is typically made from 80 / 5 and 66 / 7 twisted coarse abrasive, but untwisted yarn can also be used. High-silica fiber possesses good cutting properties and a high resin absorption capacity. In this application, the reinforcing fiber is preferably high-silica fiber or a composite of high-silica fiber and other reinforcing fibers.

[0097] Basalt fiber is a fiber made from natural basalt. It is a new type of inorganic, environmentally friendly, high-performance fiber material composed of oxides such as silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide, iron oxide, and zirconium dioxide. Basalt fiber not only boasts high strength but also possesses excellent properties such as electrical insulation, corrosion resistance, and high-temperature resistance.

[0098] Carbon fiber refers to high-strength, high-modulus fibers with a carbon content of over 90%. It possesses excellent high-temperature resistance, abrasion resistance, and corrosion resistance. Carbon fiber has a low density and high specific strength and modulus, and is often used as a reinforcing material in composites with resins, metals, ceramics, and carbon to manufacture advanced composite materials.

[0099] Aramid, also known as aromatic polyamide, is a synthetic fiber made from aromatic raw materials through polycondensation and spinning. This type of fiber has excellent heat resistance and insulation properties, stable chemical properties, and good resistance to weak acids, weak alkalis, and most organic solvents. The main varieties are poly(p-phenylene terephthalamide) fiber and poly(m-phenylene isophthalamide) fiber.

[0100] Ceramic fiber is a fibrous, lightweight refractory material with advantages such as light weight, high temperature resistance, good thermal stability, low thermal conductivity, low specific heat, and resistance to mechanical vibration. Therefore, it has been widely used in industries such as machinery, metallurgy, chemical engineering, petroleum, ceramics, glass, and electronics. The ceramic fiber used in this application can be ordinary ceramic fiber, also known as aluminosilicate fiber. To further improve the service temperature, zirconium oxide or chromium oxide can be added to the ceramic fiber.

[0101] The reinforcing fiber of this application can be glass fiber, ceramic fiber, aramid fiber, carbon fiber, basalt fiber, or natural fiber used alone; preferably, glass fiber is used in combination with ceramic fiber, aramid fiber, carbon fiber, or basalt fiber, or ceramic fiber, aramid fiber, carbon fiber, or basalt fiber are used in combination.

[0102] A molding agent is an auxiliary agent that binds loose reinforcing fibers into a cohesive whole. The molding agent impregnates and coats the surface of the reinforcing fibers and / or fills the gaps between them to prevent air leakage during use. Depending on its role in this application, the molding agent can be referred to as an adhesive, bonding loose reinforcing fibers into a relatively dense whole. The weight ratio of reinforcing fibers to molding agent is ≤1:0.25, preferably 1:0.25-1:2.5, more preferably 1:0.25-1:2, and even more preferably 1:1-1:2. At this weight ratio, the molding agent is uniformly dispersed on the surface of the reinforcing fibers. When the weight ratio of reinforcing fiber to molding agent is too high, exceeding 1:0.25, the molding agent cannot fully impregnate the reinforcing fiber. On one hand, the reinforcing fiber cannot be molded into a cohesive whole, remaining loose in some areas, affecting the thermal insulation performance of the composite material. On the other hand, the unimpregnated reinforcing fiber may leak air, posing a risk of flame propagation should the battery cell spontaneously combust during use. Of course, higher molding agent dosage is not always better. Increasing the amount of molding agent inevitably increases production costs, and excessive molding agent, while ensuring sufficient impregnation of the reinforcing fiber, results in waste.

[0103] Molding agents include inorganic and organic molding agents. Inorganic molding agents include phosphate, silicate, sulfate, and borate molding agents. Silicate and borate molding agents are preferred, and silicate molding agents are more preferred. CN201510589894.7 discloses a high-temperature resistant and rapidly degrading inorganic adhesive; CN202110095861.2 discloses a high-temperature resistant inorganic adhesive and its preparation method; CN202111140148.1 discloses a silicate inorganic adhesive and its preparation and application methods.

[0104] Silicate molding agents include base materials, plasticizers, additives, stabilizers, and coupling agents.

[0105] The base materials include aqueous solutions of sodium silicate, potassium silicate, and magnesium silicate.

[0106] Plasticizers include aluminum oxide, zinc oxide, magnesium oxide, lead oxide, copper oxide, iron oxide, zinc oxide, silicon dioxide, quartz sand, boron nitride, zirconium oxide, kaolin, ceramic fiber, carbon fiber, zirconium dioxide, titanium dioxide, zinc dioxide, boron oxide, and ceramic microspheres.

[0107] The additives include ammonium carbonate, o-benzoyl sulfonamide, cellulose, sodium alginate, gelatinized starch, polyvinyl alcohol, and methylcellulose.

[0108] Stabilizers include polysiloxanes, acetic acid, and styrene-acrylic emulsions.

[0109] Coupling agents include silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, and borate coupling agents.

[0110] Organic molding agents include unsaturated resins, polyurethanes, and polypropylene molding agents, with epoxy resins, polyester resins, and polyurethane molding agents being preferred.

[0111] Polyurethane is a high molecular polymer made from isocyanate and polyol as the main raw materials, and foamed on-site by high-pressure spraying under the action of various additives such as foaming agents, catalysts, and flame retardants.

[0112] Isocyanates, including any isocyanate known for the preparation of polyurethanes, can be aliphatic, alicyclic, aryliphatic, and / or aromatic isocyanates, such as 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate, 1-methylcyclohexane 2,4-diisocyanate, isophorone diisocyanate, 2,2'-diisocyanate, butylene 1,4-diisocyanate, cyclohexane 1,4-diisocyanate, diphenylmethane 2,2'-diisocyanate, and naphthylene 1,5-diisocyanate. The above-mentioned isocyanates can also be used in the form of isocyanate prepolymers. Isocyanate prepolymers can be obtained by reacting the above-mentioned isocyanates with another polyol at a temperature of 80-100°C.

[0113] Polyols, specifically polyols reactive with isocyanates, including any polyols used in the preparation of polyurethanes in the art that have at least two reactive hydrogen atoms, can be used here. For example... 2095 (BASF) 2090 (BASF) 3905 (BASF) 3907 (BASF) 3909 (BASF) 3505 / 1 (BASF). The preferred polyol is a polyether polyol with a weight-average molecular weight of 200 to 10,000.

[0114] Foaming agents include chemical foaming agents, physical foaming agents, and water. Chemical foaming agents are compounds that react with isocyanates to form gaseous products (such as water or formic acid). Physical foaming agents are compounds that can be dissolved in the reactants and evaporate during the polyurethane formation process.

[0115] Catalysts are additives that accelerate the formation of polyurethane, including organometallic catalysts and amine catalysts. Examples of organometallic catalysts include tin acetate, tin octanoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dioctyltin diacetate, potassium acetate, and potassium formate. Examples of amine catalysts include N,N,N,N,N-pentamethyldiethylenetriamine, N,N,N-triethylaminoethoxyethanol, dimethylcyclohexylamine, trimethylhydroxyethylethylenediamine, dimethylbenzylamine, and triethylamine.

[0116] Flame retardants include tris(2-chloroisopropyl) phosphate, melamine, ammonium polyphosphate, expandable graphite, etc.

[0117] Other additives include surfactants, preservatives, colorants, antioxidants, reinforcing agents, stabilizers, and water-absorbing agents.

[0118] The polyurethane in this application can be prepared using existing methods or can be directly purchased from commercially available products, such as those from BASF, Huafeng Group, Cargill Investment (China) Co., Ltd., etc.

[0119] In this application, polyurethane is coated onto the surface of reinforcing fibers in the thermal insulation composite material. Coating methods include spraying, applying polyurethane to the surface of the reinforcing fibers; injection, injecting polyurethane into the surface of the reinforcing fibers; or immersing the reinforcing fibers in a polyurethane forming system to uniformly disperse the polyurethane on the surface of the reinforcing fibers. Any method that disperses polyurethane on the surface of the reinforcing fibers falls within the scope of the term "coating" in this application, resulting in polyurethane dispersion on the surface of the reinforcing fibers.

[0120] Unsaturated resin is a polymer compound containing unsaturated double bonds. Unsaturated resins include polyester resin, epoxy resin, and alkyd resin; this application preferably uses polyester resin and epoxy resin. CN202311857072.3 discloses a polyester resin for an adhesive used in aluminum-plastic film, its preparation method, and its application; CN202011614271.8 discloses a polyester resin for making an adhesive for aluminum-plastic film, its preparation method, and its application; CN201911367597.3 discloses a high-toughness, impact-resistant polyester resin for lithium battery aluminum-plastic film composites.

[0121] Polyester resin includes the following raw materials: polyols, diacids, dimer acids, alicyclic monomers, and catalysts.

[0122] Polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, methylpropanediol, hexanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,5-pentanediol, trimethylolpropane, glycerol, neopentanediol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, and 2-butyl-2-ethyl-1,3-propanediol.

[0123] Dicarboxylic acids include aliphatic dicarboxylic acids and aromatic dicarboxylic acids. Aromatic dicarboxylic acids include isophthalic acid, phthalic acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, azelaic acid, and sebacic acid.

[0124] Alicyclic monomers include 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediethanol, 1,4-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic ester.

[0125] Catalysts include antimony acetate, antimony glycolate, tetrabutyl titanate, isopropyl titanate, dibutyltin dilaurate, monobutyltin oxide, dibutyltin oxide, monobutyltriisooctanoate, dioctyltin oxide, dihydroxybutyltin chloride, zinc oxalate, and zinc acetate.

[0126] Epoxy resin is formulated from epoxy resin base material, curing agent, diluent, accelerator, and filler. CN2020112810147 provides a two-component epoxy adhesive with high heat resistance and high peel strength; CN2013107238478 provides a high-temperature resistant flame-retardant epoxy adhesive and its preparation method; CN2022110728378 provides an epoxy adhesive for high-temperature use and its preparation method. CN201510457727.7 provides an epoxy resin AB adhesive for high-temperature environments and its preparation and application methods.

[0127] Epoxy resin molding agents are widely used in the home appliance, automotive, water conservancy and transportation, electronics and aerospace industries due to their good stability and excellent bonding properties.

[0128] Epoxy resin base materials include bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, multifunctional epoxy resin, aliphatic epoxy resin, and hydantoin epoxy resin.

[0129] The curing agent can be selected from diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, and diaminodiphenyl sulfone.

[0130] The diluents include benzyl alcohol, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, phenyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cashew phenol glycidyl ether, and pentaerythritol tetraglycidyl ether.

[0131] Accelerators include resorcinol, salicylic acid, methyltetrahydrophthalic anhydride, dimethylbenzylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicycloundec-7-ene.

[0132] The fillers include calcium carbonate, alumina, zinc oxide, talc, magnesium oxide, zirconium oxide, silicon dioxide, mica powder, kaolin, silica powder, and fumed silica.

[0133] Polypropylene (PP) is a polymer formed by the addition polymerization of propylene. It is a high-performance thermoplastic synthetic resin with excellent chemical resistance, heat resistance, electrical insulation, high mechanical strength, and good abrasion resistance. To further improve heat resistance, polypropylene can be modified, such as through copolymerization, crosslinking, grafting, or the addition of nucleating agents, to alter the polymer components and macromolecular structure or crystal configuration, thereby improving its mechanical properties, heat resistance, and aging resistance.

[0134] In the polypropylene molding process, fillers such as silicates, calcium carbonate, silica, cellulose, and glass fibers are added to the polymer to modify the polypropylene, resulting in improved heat resistance, reduced cost, and increased rigidity. Glass fiber, as a high-performance inorganic non-metallic whisker, is widely used due to its low price, good insulation, strong heat resistance, good corrosion resistance, and high mechanical strength. The performance of PP modified with glass fiber is significantly improved, with the amount of glass fiber used being around 30%.

[0135] To meet the thermal insulation performance requirements of the thermal insulation composite material, the molding agent needs to pass the UL 94V0 flame retardancy test. Therefore, the molding agent is not limited to the types described above; any molding agent that meets the UL 94V0 standard can be used in this application.

[0136] The UL 94V0 standard is a testing standard for the flammability of plastics, developed by U.S. safety laboratories. This standard evaluates the flammability and flame retardancy of plastic materials under flame conditions. The UL 94V0 standard is primarily used to assess the flame retardancy of plastic components in electronic and electrical equipment. The V0 level is one of the highest flame retardancy ratings in the UL 94 standard, indicating that the material stops burning within 10 seconds after the flame is removed under specific test conditions and does not exhibit flame drop. This rating is typically used for plastic components in electronic products and equipment requiring high flame retardancy. The UL 94V0 standard has wide applications and sets stringent requirements for the flame retardancy of plastic materials.

[0137] The thermal insulation composite material formed in this application is a sheet material with a thickness ≥0.2mm, preferably ≥0.5mm. To meet the requirements of lightweighting, the thickness of the resulting composite material is 0.2mm-3mm. More preferably, the thickness is 0.5mm-3mm. Even more preferably, the thickness is 0.5mm-2mm. The thickness of the thermal insulation composite material obtained in this application is affected by the thickness of the reinforcing fibers themselves. If the reinforcing fibers used are relatively thick, the resulting composite material will also be thicker; conversely, if thinner reinforcing fibers are used, the resulting composite material will also be thinner. To adapt to the needs of different application scenarios, the thickness of the resulting composite material is adjusted within the range of 0.2mm-3mm. Experimental verification shows that the thermal insulation performance of the thermal insulation composite material in this application is not significantly affected within this thickness range. Of course, further increasing the thickness of the thermal insulation composite material will improve its thermal insulation performance; therefore, the thermal insulation composite material can be selected within a thickness range ≥0.2mm.

[0138] The preparation method of the above-mentioned thermal insulation composite material is as follows:

[0139] S1. Lay up continuous phase reinforcing fibers and discontinuous phase reinforcing fibers to form a reinforcing fiber layer;

[0140] S2. Spray or inject the molding agent onto the reinforcing fiber layer;

[0141] S3. Hot pressing in a mold to obtain a sprayed or injected product, thus obtaining a heat-insulating composite material.

[0142] In step S1, continuous phase reinforcing fibers and discontinuous phase reinforcing fibers can be laid alternately, that is, after one layer of continuous phase reinforcing fibers, another layer of discontinuous phase reinforcing fibers is added, and the above laying operation is repeated. Alternatively, they can be laid continuously, that is, first lay continuous phase reinforcing fibers, and then lay discontinuous phase reinforcing fibers; or first lay discontinuous phase reinforcing fibers, and then lay continuous phase reinforcing fibers.

[0143] In step S2, the molding agent is sprayed or injected onto both sides of the reinforcing fiber layer. If a polyurethane molding agent is used, isocyanate, polyol, foaming agent, catalyst, and flame retardant can be selected according to existing preparation methods and mixed at a temperature of 20-80°C to obtain a mixture. This mixture is then sprayed onto the reinforcing fiber layer using a nozzle. Specifically, after spraying onto one surface of the reinforcing fiber layer, the reinforcing fiber layer is reversed, and spraying continues onto the other surface. Alternatively, commercially available polyurethane, such as polyurethane purchased from BASF (comprising component A, isocyanate, and component B, polyol), can be used. First, the isocyanate and polyol are mixed, and then the mixture is sprayed onto the reinforcing fiber layer using a nozzle. Besides spraying, injection molding can also be used, i.e., injecting the mixture or commercially available polyurethane foam onto the reinforcing fiber layer through an injection head.

[0144] The hot pressing in step S3 is a conventional hot pressing process, with a temperature of 40-180℃ and a pressure of 100-2000t.

[0145] After the hot pressing operation in step S3, demolding and trimming operations are also included.

[0146] When the molding agent is an unsaturated resin, the preparation method of the thermal insulation composite material is similar to that when polyurethane is used as the molding agent. Spraying is the preferred choice when using both polyurethane and unsaturated resin as molding agents. However, when polypropylene is selected as the molding agent, injection molding is the preferred option.

[0147] The heat-insulating composite material obtained above can be used in cover plates, such as cover plates for new energy vehicle batteries.

[0148] The cover plate contains the aforementioned thermal insulation composite material.

[0149] The cover plate also includes at least one metal sheet located on at least one side of the thermal insulation composite material. In addition to the thermal insulation composite material, the cover plate has metal sheets on one or both sides of the thermal insulation composite material; there may be one or more metal sheets. The metal sheets are made of aluminum alloy, iron, steel, or aluminum, and their thickness is selected to be 0.08-1.2 mm, preferably 0.2-1.2 mm, and more preferably 0.5-1.0 mm.

[0150] Of course, there can be only one metal sheet, with two layers of thermal insulation composite material, located on both sides of the metal sheet. Alternatively, there can be only one layer of thermal insulation composite material, with the metal sheet on top. Multiple metal sheets can also be used, with smaller sizes and placed only in locations where the battery cell is prone to ejection or radiation.

[0151] The metal plates are designed to improve the electromagnetic shielding performance of the cover, reducing the risk of injury to drivers and passengers from the batteries in new energy vehicles. They also enhance the mechanical strength of the cover.

[0152] Electrophoretic treatment is applied to the surface of the metal sheet. In situations where the metal sheet may come into direct contact with the battery, the small space between the metal sheet and the battery could generate electrical sparks during use, potentially damaging the metal sheet. Therefore, electrophoresis is necessary to prevent corrosion of the metal sheet.

[0153] The metal sheets in the cover plate are roughly the same size as the thermal insulation composite material.

[0154] To reduce weight, the metal sheet can be cut into small pieces and placed in locations prone to radiation, achieving both shielding performance and weight reduction, thus lowering costs.

[0155] The cover plate also includes at least one heat insulation layer, and the heat insulation composite material consists of two layers, located on both sides of the heat insulation layer.

[0156] The insulation layer comprises an adhesive and an insulation material, with the insulation material distributed within the adhesive. The insulation layer can be an intumescent insulation layer, in which case the insulation material is an intumescent insulation material. Intumescent insulation materials, when exposed to high temperatures, release non-flammable gases and / or water vapor, expanding to form a foam layer. The released non-flammable gases and / or water vapor dilute the surrounding oxygen density, thereby reducing the fire risk. The formed foam layer, due to its loose structure, has good insulation properties and can prevent high temperatures from spreading to the surrounding environment, thus acting as a good insulation barrier. Intumescent insulation materials include ammonium polyphosphate, melamine-formaldehyde, methylated melamine, urea, dimethylurea, p-toluenesulfonate, sodium sulfate, ammonium pentaborate, aluminum borate, pentaerythritol, kaolin, etc. The adhesive can be polyurethane. Of course, other insulation materials can also be selected as the insulation layer; the purpose of the insulation layer is to further improve the insulation effect.

[0157] At least one metal sheet is placed between the thermal insulation composite material and the thermal insulation layer in the cover plate. In this case, the metal sheet is placed between the thermal insulation composite material and the thermal insulation layer, which can not only serve as a shield, but also prevent damage to the surface of the metal sheet caused by electrical sparks.

[0158] The aforementioned thermal insulation composite material can also be used as a lower tray for new energy vehicle battery modules. The lower tray, located below the battery module, is typically made of aluminum profile and serves to support the battery. Based on the excellent thermal insulation performance of the composite material described in this application, the composite material can be used as a lower tray or bonded to a metal sheet to serve as a lower tray.

[0159] This application also provides a battery module, which includes an energy storage battery cell, and further includes the aforementioned cover plate and / or the aforementioned lower tray, wherein the cover plate is located above or on both sides of the energy storage battery cell, and the lower tray is located below the energy storage battery cell.

[0160] The molding agents used in the following examples all passed the flame retardancy test of UL 94-2013 at the V0 level.

[0161] Example 1

[0162] The reinforcing fiber is 100% by weight in discontinuous phase form, containing no continuous phase reinforcing fiber. The reinforcing fiber material is glass fiber, and the length of the discontinuous phase reinforcing fiber ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF (BASF sells component A isocyanate, component B polyol, flame retardant, and other additives as a set; it is prepared and used immediately). The weight ratio of reinforcing fiber to molding agent is 1:2.5.

[0163] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0164] Example 2

[0165] The reinforcing fibers comprise 57% by weight of discontinuous phase reinforcing fibers and 43% by weight of continuous phase reinforcing fibers. The reinforcing fibers are made of carbon fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1.

[0166] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0167] Example 3

[0168] The reinforcing fibers comprise 36% by weight of discontinuous phase reinforcing fibers and 64% by weight of continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:0.8.

[0169] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0170] Example 4

[0171] The reinforcing fibers comprise 45% by weight of discontinuous phase reinforcing fibers and 55% by weight of continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1.

[0172] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0173] Example 5

[0174] The reinforcing fibers comprise 25.9 wt% discontinuous phase reinforcing fibers and 74.1 wt% continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the discontinuous phase reinforcing fibers have a length of 3-100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:0.25.

[0175] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is then placed into an open mold at approximately atmospheric pressure. The mold is preheated at approximately 110°C and designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the fiber is demolded to obtain a thermal insulation composite material with a thickness of approximately 1.5mm.

[0176] Example 6

[0177] The reinforcing fiber comprises 100% by weight of discontinuous phase reinforcing fiber. The reinforcing fiber is made of glass fiber, and the length of the discontinuous phase reinforcing fiber is 3-100 mm. The molding agent is an inorganic molding agent, purchased from HBFULLER as CILBOND R-7264. The weight ratio of reinforcing fiber to molding agent is 1:0.5.

[0178] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is then placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the fiber is demolded to obtain a thermal insulation composite material with a thickness of approximately 3mm.

[0179] Example 7

[0180] The reinforcing fiber comprises 100% by weight of discontinuous phase reinforcing fiber. The reinforcing fiber is made of carbon fiber, and the length of the discontinuous phase reinforcing fiber is 3-100 mm. The forming agent is an inorganic forming agent, purchased from Henkel AG, Inc., C3006. The weight ratio of reinforcing fiber to forming agent is 1:2.

[0181] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is then placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the material is demolded to obtain a thermal insulation composite material with a thickness of approximately 3.3mm.

[0182] Example 8

[0183] The reinforcing fibers comprise 44.83 wt% discontinuous phase reinforcing fibers and 55.17 wt% continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the discontinuous phase reinforcing fibers range in length from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:0.5.

[0184] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0185] Example 9

[0186] The reinforcing fibers comprise 48.88 wt% discontinuous phase reinforcing fibers and 51.12 wt% continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the discontinuous phase reinforcing fibers range in length from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1.5.

[0187] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0188] Example 10

[0189] The reinforcing fibers comprise 36% by weight of discontinuous phase reinforcing fibers and 64% by weight of continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1.

[0190] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0191] Example 11

[0192] The reinforcing fiber comprises 67% by weight of discontinuous phase reinforcing fiber and 33% by weight of continuous phase reinforcing fiber. The reinforcing fiber is made of glass fiber, and the length of the discontinuous phase reinforcing fiber ranges from 3 to 100 mm. The molding agent is unsaturated polyester resin, purchased from Changzhou Huari New Materials Co., Ltd. The weight ratio of reinforcing fiber to molding agent is 1:1.

[0193] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0194] Example 12

[0195] The reinforcing fibers comprise 56% by weight of discontinuous phase reinforcing fibers and 44% by weight of continuous phase reinforcing fibers. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1.

[0196] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is placed into an open mold at approximately atmospheric pressure. The mold has been preheated at approximately 110°C and is designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the mold is demolded to obtain a thermal insulation composite material with a thickness of approximately 2mm.

[0197] Example 13

[0198] The reinforcing fiber comprises 100% by weight of discontinuous phase reinforcing fiber. The reinforcing fiber is made of glass fiber, and the length of the discontinuous phase reinforcing fiber is 3-100 mm. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fiber to molding agent is 1:1.5.

[0199] The molding agent is sprayed onto the surface of the reinforcing fiber. The sprayed reinforcing fiber is then placed into an open mold at approximately atmospheric pressure. The mold is preheated at approximately 110°C and designed with tools for cutting, trimming, and drilling screw holes. The mold is then closed and clamped at approximately 500t. After molding for 45 seconds to 4 minutes, the material is demolded to obtain a thermal insulation composite material with a thickness of approximately 0.5mm.

[0200] Compare with Example 1

[0201] The reinforcing fiber is a 100% continuous phase fiber, made of glass fiber, and the molding agent is thermoplastic polypropylene (PP). The weight ratio of reinforcing fiber to molding agent is 1:1. A 2mm thermal insulation composite material was obtained using the same method as in Example 1.

[0202] Compare with Example 2

[0203] The reinforcing fibers comprise 20% by weight of discontinuous phase reinforcing fibers and 80% by weight of continuous phase reinforcing fibers. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers is 3-100 mm. A 2 mm thermal insulation composite material was obtained using the same method as in Example 1.

[0204] Compare with Example 3

[0205] The reinforcing fibers comprise 7.6 wt% discontinuous phase reinforcing fibers and 92.4 wt% continuous phase reinforcing fibers. The molding agent is polyurethane, purchased from BASF. The weight ratio of reinforcing fibers to molding agent is 1:1. The reinforcing fibers are made of glass fiber, and the length of the discontinuous phase reinforcing fibers ranges from 3 to 100 mm. A 2 mm thermal insulation composite material was obtained using the same method as in Example 1.

[0206] I. Thermal Insulation Performance Test

[0207] The thermal insulation performance of the thermal insulation composite materials prepared in Examples 1, 2, 1, and 2 were tested.

[0208] Test method: A 2mm thick layer of the thermal insulation composite material was subjected to high-temperature burning at 1300℃ and 0.5 MPa pressure for 90 seconds, followed by further burning at 900℃. One side of the thermal insulation composite material was burned, and the other side was observed to see if it was burned through, and its temperature was measured. The changes in the thermal insulation composite material before and after burning, as well as the temperature changes during the high-temperature burning, were compared. A comparison diagram of the thermal insulation composite material prepared in Example 1 before and after burning is shown below. Figure 1 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 2 As shown; comparison images of the thermal insulation composite material prepared in Example 2 before and after calcination are shown below. Figure 3 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 4 As shown, the comparison diagrams of the heat-insulating composite material prepared in Comparative Example 1 before and after calcination are as follows. Figure 5 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 6 As shown.

[0209] The test results of the thermal insulation performance of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 are shown in Table 1.

[0210] Table 1

[0211] Test temperature Testing time Back temperature Has it burned through? result Example 1 1300℃ 10min 260℃ no pass Example 2 1300℃ 11min 290.92℃ no pass Compare with Example 1 1300℃ 36s 972℃ yes Not passed Compare with Example 2 1300℃ 329s 319℃ yes Not passed

[0212] As shown in Table 1, the thermal insulation composite material prepared in Example 1, after being burned at 1300°C for 90 seconds and then further burned at 900°C for 8.5 minutes (i.e., the entire test lasted 10 minutes), had a back surface temperature (the burned surface of the thermal insulation composite material is referred to as the front surface, and the opposite side of the burned surface as the back surface) of only 260°C, which is below 300°C. Furthermore, the thermal insulation composite material was not burned through and passed the thermal insulation performance test, demonstrating excellent thermal insulation performance. The thermal insulation composite material prepared in Example 2, after being burned at 1300°C for 90 seconds and then further burned at 900°C for 9.5 minutes (i.e., the entire test lasted 11 minutes), had a back surface temperature of 290.92°C, still below 300°C, and again, the thermal insulation composite material was not burned through. In contrast, the thermal insulation composite material prepared in Comparative Example 1, after being burned at 1300°C for 36 seconds, had a back surface temperature as high as 972°C, and the thermal insulation composite material was burned through. The thermal insulation composite material prepared in Comparative Example 2 was subjected to high-temperature burning at 1300°C for 80 seconds, and then placed at 900°C for 249 seconds. The entire test lasted for 329 seconds, and the temperature on the back side reached 319°C, exceeding 300°C.

[0213] Since the flame temperature is usually around 1000℃ when the battery cell is burning, and the high temperature environment of 1300℃ is a relatively extreme condition, this application takes the heat insulation composite material prepared in Example 6 and Example 7 as an example and conducts a heat insulation performance test at 1000℃ for 10 minutes of continuous burning.

[0214] The heat-insulating composite material prepared in Example 6 is shown in the comparison diagram before and after calcination. Figure 7 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 8 As shown; comparison images of the thermal insulation composite material prepared in Example 7 before and after calcination are shown below. Figure 9 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 10 As shown.

[0215] The test results of the thermal insulation performance of the thermal insulation composite materials in Examples 6 and 7 are shown in Table 2.

[0216] Table 2

[0217] Test temperature Testing time Back temperature Has it burned through? result Example 6 1000℃ 10min 250℃ no pass Example 7 1000℃ 10min 217℃ no pass

[0218] As shown in Table 2, the thermal insulation composite material prepared in this application, after being continuously burned at 1000°C for 10 minutes, has a back surface temperature of less than 300°C and is not burned through, demonstrating excellent thermal insulation performance.

[0219] The aforementioned thermal insulation composite material has a thickness of approximately 3 mm. To examine the thermal insulation performance of a thinner composite material, this application uses the thermal insulation composite material prepared in Example 13 as an example and conducts a thermal insulation performance test by continuous burning at 1000°C for 15 minutes. The thermal insulation composite material prepared in Example 13 has a thickness of only 0.5 mm. Comparison images of the thermal insulation composite material prepared in Example 13 before and after burning are shown below. Figure 11 As shown in the figure, the temperature change during high-temperature burning is as follows: Figure 12 shown

[0220] The test results of the thermal insulation performance test of the thermal insulation composite material in Example 13 are shown in Table 3.

[0221] Table 3

[0222] Test temperature Testing time Back temperature Has it burned through? result Example 13 1000℃ 15min 517℃ no pass

[0223] As shown in Table 3, when the thickness of the thermal insulation composite material is 0.5 mm, after continuous burning at 1000℃ for 15 minutes, although the temperature on the back side increases, it is still not burned through.

[0224] In addition, for the 0.5mm thick thermal insulation composite material, this application also conducted insulation performance tests on breakdown voltage and tracking, with the breakdown voltage test conducted using standard IEC 60243-1:2013 and the tracking test conducted using standard IEC 60112 or ASTM D3638.

[0225] Five thermal insulation composite materials prepared in Example 13 were used, with sample thicknesses ranging from 0.5 to 0.6 mm, and the average thickness was calculated to be 0.582 mm. The breakdown voltage was tested before and after continuous burning at 1000°C for 15 minutes. The results showed that the average breakdown voltage before burning was 20.49 kV / mm, and the breakdown voltage after continuous burning at 1000°C for 15 minutes was 11.60 kV / mm. Therefore, the thermal insulation composite material prepared in this application exhibits excellent insulation performance at high temperatures. The same results were obtained in the tracking test.

[0226] II. Fire resistance performance test

[0227] 1. The formulation of the thermal insulation composite material used is as follows:

[0228] Table 4

[0229] Percentage of discontinuous phase reinforcing fibers Percentage of continuous phase reinforcing fibers Example 5 25.9％ 74.1％ Example 8 44.83％ 55.17％ Example 9 48.88％ 51.12％ Example 10 36％ 64％

[0230] 2. Fire resistance performance testing methods

[0231] Five temperature sensors were installed on the back of the thermal insulation composite material prepared in Example 5, and labeled as 1, 2, 3, 4, and 5 respectively. Figure 13 As shown, the temperature of the back side of the thermal insulation composite material is tested. A sixth temperature sensor is installed near the flame location of the test material to test the flame temperature, as shown. Figure 14 As shown. The thermal insulation composite material prepared in Example 5 was placed in an environment of 0.5 MPa pressure and 1000°C for 30 minutes of high-temperature burning. The front side of the thermal insulation composite material was burned, and it was observed whether the back side was burned through. The temperature changes of the thermal insulation composite material prepared in Example 5 during the burning process, as measured by various temperature sensors, are shown below. Figure 15 As shown, the condition of the back side after burning is as follows. Figure 16 As shown.

[0232] The highest back surface temperature and burn-through of the thermal insulation composite material prepared in Example 5 after scorching are shown in Table 5.

[0233] Table 5

[0234] Maximum flame temperature / °C Maximum temperature on the back / °C Was it burned through? Example 5 1036.5 420.46 no

[0235] To further investigate the fire resistance of the thermal insulation composite material prepared in this application at higher temperatures, the thermal insulation composite materials prepared in Examples 8-10 were subjected to high-temperature burning at 0.5 MPa pressure and 1300°C for 30 minutes. The front side of the thermal insulation composite material was burned, and it was observed whether the back side was burned through. The temperature changes measured by various temperature sensors during the burning process of the thermal insulation composite material prepared in Example 8 are as follows: Figure 17 As shown, the condition of the back side after burning is as follows. Figure 18 As shown. The temperature changes of the thermal insulation composite material prepared in Example 9, as measured by various temperature sensors during the firing process, are as follows. Figure 19 As shown, the condition of the back side after burning is as follows. Figure 20 As shown; the temperature changes of the thermal insulation composite material prepared in Example 10, as measured by various temperature sensors during the burning process, are as follows. Figure 21 As shown, the condition of the back side after burning is as follows. Figure 22 As shown.

[0236] The highest back surface temperature and burn-through of the thermal insulation composite materials prepared in Examples 8-10 after scorching are shown in Table 6.

[0237] Table 6

[0238] Maximum flame temperature / °C Maximum temperature on the back / °C Was it burned through? Example 8 1326.54 498.96 no Example 9 1332.75 542.67 no Example 10 1365.85 498.98 no

[0239] As shown in Table 6, the heat-insulating composite materials prepared in Examples 8-10, after being burned at 1300℃ for 30 minutes, had a maximum back temperature of about 500℃ and were not burned through, demonstrating excellent fire resistance.

[0240] III. Real Cell Testing

[0241] To further test whether the thermal insulation composite material prepared in this invention poses a risk of burn-through when exposed to a battery cell explosion, a real battery cell explosion test was conducted as follows. The battery cell used was a 6-series ternary lithium battery cell with a voltage of 4.4V, a square-shell cell with dimensions of 150*52*103mm, and a capacity of 117Ah. A schematic diagram of the installation of each component in the battery cell explosion test is shown below. Figure 23 As shown in the diagram, the location of the thermal insulation composite material during the battery cell explosion experiment is as follows: Figure 24 As shown. Taking the thermal insulation composite material prepared in Example 3 as an example, it was installed on the battery pack cover and used for a real cell burst test. The maximum pressure inside the battery pack was about 100 kPa. During the test, the temperature on the back of the thermal insulation composite material was measured, and the temperature change curve is shown in the figure. Figure 25 As shown, after the test, the back of the cover plate is as follows: Figure 26 As shown.

[0242] The highest back surface temperature and burn-through of the thermal insulation composite material prepared in Example 3 after burning are shown in Table 7.

[0243] Table 7

[0244]

[0245] As can be seen, the heat-insulating composite material prepared in this application did not burn through in the simulated cell explosion test, and can be used for battery pack covers, increasing the safety of use.

[0246] In addition, a real cell burst test was commissioned to UL laboratory (referring to UL2596 testing standard), using the thermal insulation composite materials prepared in Example 3 and Example 12 as examples for testing.

[0247] The following is a description of the actual battery cell explosion test, and the implementation process is as follows:

[0248] 1. Install 25 lithium-ion cells and a flexible heating film inside the test chamber. The 25 lithium-ion cells are arranged in a 5×5 array.

[0249] The test chamber is a steel-cased test chamber measuring 100mm (length) × 100mm (width) × 75-89mm (height), with an open top. The battery cells used are Panasonic NCR18650B type, with a capacity of 3350mAh, and each cell is charged to 100%. Adjacent cells are in contact with each other, as shown in the schematic diagram below. Figure 27 As shown. A flexible heating film is used to drive the fuel pack, causing the test chamber to enter a state of thermal runaway.

[0250] 2. The thermal insulation composite materials prepared in Example 3 and Example 12 are sealed in the top open position of the test box. The thermal insulation composite material prepared in Example 3 is placed alone as the test sample on the top of the test box, while the thermal insulation composite material prepared in Example 12 is bonded to a 0.7mm steel plate and placed as the test sample on the top of the test box (the thermal insulation composite material is placed at the end closest to the battery cell).

[0251] 3. Install thermocouples at the center of the battery cell and on the outer surface of the sample to be tested, respectively, to monitor the battery temperature and the outer surface temperature of the sample.

[0252] 4. Heat the two flexible heating films at a rate of approximately 6°C / min to heat the test chamber.

[0253] 5. Visually observe and record the test sample for at least 5 minutes after the onset of thermal runaway, noting any signs of cracking, smoke, or burning.

[0254] Each sample was tested for 3 rounds. When the thermal insulation composite material prepared in Example 3 was used for real cell testing, the test results are shown in Figure 8.

[0255] Table 8

[0256]

[0257] As shown in Table 8, the target pressure for all three tests was 250 kPa, and the actual internal pressure exceeded the target pressure. The results of the three tests were consistent, with no burn-through observed. However, during the test, due to excessive pressure inside the test chamber, the top of the test chamber bulged and smoke overflowed.

[0258] The thermal insulation composite material prepared in Example 12 was placed on top of the test chamber along with a 0.7mm steel plate as a top cover. The test results are shown in Table 9 when the actual battery cell was tested.

[0259] Table 9

[0260]

[0261] Existing battery pack covers primarily use mica sheets. Mica itself has excellent thermal insulation properties, with a thermal conductivity of only 0.35 W / (m·K). However, mica is associated with issues related to child labor, necessitating the search for alternative materials. Furthermore, mica has a density of 2.77 g / cm³. 3 It is relatively heavy, which contradicts the current demand for lightweight automobiles.

[0262] To examine whether the thermal insulation composite material prepared in this application can replace mica, the performance of the thermal insulation composite material prepared in this application is compared with that of mica, as shown in Table 10.

[0263] Table 10

[0264]

[0265] As shown in Table 10, the thermal insulation composite material prepared in this application has superior temperature resistance compared to mica; and its density is lower than that of mica, meeting the current requirements for lightweight applications. Furthermore, since mica is only used as an accessory and cannot be used alone, the composite material obtained in this application can be used independently, replacing mica and improving ease of use.

[0266] The thermal insulation composite material prepared in this application may have some mechanical properties (such as the tensile strength corresponding to Example 1) that are inferior to those of mica. Using the thermal insulation composite material prepared in this application in conjunction with metal sheets can overcome these mechanical property deficiencies and meet the requirements for battery cover applications. Therefore, the thermal insulation composite material prepared in this application can be used independently or in conjunction with metal sheets to replace mica, overcoming the limitations of mica's use.

[0267] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A thermal insulation composite material, characterized in that, The product comprises reinforcing fibers and a molding agent coated on the surface of the reinforcing fibers. The reinforcing fibers comprise 0-74% by weight of continuous phase reinforcing fibers and 26-100% by weight of discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers. The molding agent has passed the UL 94V0 flame retardancy test. The molding agent includes inorganic molding agents and organic molding agents. The inorganic molding agents include phosphate, silicate, sulfate, and borate molding agents. The organic molding agents include epoxy resin and polyurethane molding agents. The molding agent impregnates and coats the surface of the reinforcing fibers and / or fills the gaps between the reinforcing fibers to prevent air leakage during use. The polyurethane molding agent is a polymer foamed on-site by high-pressure spraying.

2. The thermal insulation composite material as described in claim 1, characterized in that, The reinforcing fibers comprise 0-65% by weight of continuous phase reinforcing fibers and 35-100% by weight of discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers.

3. The thermal insulation composite material as described in claim 1, characterized in that, The reinforcing fibers comprise 0-45% by weight of continuous phase reinforcing fibers and 55-100% by weight of discontinuous phase reinforcing fibers, based on the total weight of the reinforcing fibers.

4. The thermal insulation composite material as described in claim 1, characterized in that, The reinforcing fiber is selected from any one or more of glass fiber, ceramic fiber, aramid fiber, carbon fiber, basalt fiber, and natural fiber, or a mixture thereof.

5. The thermal insulation composite material as described in claim 4, characterized in that, The glass fiber contains more than 50% SiO2.

6. The thermal insulation composite material as described in claim 5, characterized in that, The glass fiber contains more than 95% SiO2.

7. The thermal insulation composite material as described in claim 4, characterized in that, The glass fiber is a high-silica fiber.

8. The thermal insulation composite material as described in claim 1, characterized in that, The reinforcing fibers in the form of a continuous phase are pads, woven fabrics, or combinations thereof.

9. The thermal insulation composite material as described in claim 1, characterized in that, The discontinuous phase reinforcing fibers are obtained by in-situ short-cutting of long fibers.

10. The thermal insulation composite material as described in claim 9, characterized in that, The length of the reinforcing fiber in the form of the discontinuous phase is 3-100 mm.

11. The thermal insulation composite material as described in claim 1, characterized in that, The weight ratio of the reinforcing fiber to the molding agent is ≤1:0.

25.

12. The thermal insulation composite material as described in claim 11, characterized in that, The weight ratio of the reinforcing fiber to the molding agent is 1:0.25-1:2.

5.

13. The thermal insulation composite material as described in claim 1, characterized in that, The thermal insulation composite material is a sheet with a thickness of ≥0.2mm.

14. The thermal insulation composite material as described in claim 13, characterized in that, The thermal insulation composite material is a sheet with a thickness of ≥0.5mm.

15. The thermal insulation composite material as described in claim 13, characterized in that, The thermal insulation composite material is a sheet with a thickness of 0.2mm-3mm.

16. The thermal insulation composite material as described in claim 15, characterized in that, The thermal insulation composite material is a sheet with a thickness of 0.5mm-3mm.

17. The thermal insulation composite material as described in claim 16, characterized in that, The thermal insulation composite material is a sheet with a thickness of 0.5mm-2mm.

18. A method for preparing the thermal insulation composite material according to any one of claims 1-17, characterized in that: S1. Lay up continuous phase reinforcing fibers and discontinuous phase reinforcing fibers to form a reinforcing fiber layer; S2. Spray or inject the molding agent onto the reinforcing fiber layer; S3. Hot pressing in a mold to obtain the sprayed or injected product, thus obtaining the heat-insulating composite material.

19. The method for preparing the thermal insulation composite material according to claim 18, characterized in that: In step S1, continuous phase reinforcing fibers and discontinuous phase reinforcing fibers are laid alternately or continuously.

20. A cover plate, characterized in that, The thermal insulation composite material comprising any one of claims 1-17 or any one of claims 18-19 prepared by the method thereof.

21. The cover plate according to claim 20, characterized in that, It also includes at least one metal sheet located on at least one side of the thermal insulation composite material.

22. The cover plate according to claim 20, characterized in that, At least one metal sheet is provided on both sides of the thermal insulation composite material.

23. The cover plate according to claim 20, characterized in that, The thermal insulation composite material consists of two layers, located on both sides of the metal sheet.

24. The cover plate according to claim 20, characterized in that, It also includes at least one layer of insulation.

25. The cover plate according to claim 24, characterized in that, The material of the insulation layer is selected from any one of calcium hydroxide, magnesium hydroxide, aluminum hydroxide, or expandable graphite.

26. The cover plate according to claim 24, characterized in that, The thermal insulation composite material consists of two layers, located on both sides of the thermal insulation layer.

27. The cover plate according to claim 24, characterized in that, At least one metal sheet is disposed between the thermal insulation composite material and the thermal insulation layer.

28. A lower tray for a battery module, characterized in that, The thermal insulation composite material comprising any one of claims 1-17 or any one of claims 18-19 prepared by the method thereof.

29. A battery module, the battery module comprising a single energy storage battery cell, characterized in that, It also includes the cover plate as described in any one of claims 20-27 and / or the lower tray as described in claim 28, wherein the cover plate is located above or on both sides of the energy storage battery cell, and the lower tray is located below the energy storage battery cell.

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