Composite material and preparation method thereof, composite protection plate and battery pack

Abstract

The invention discloses a composite material, a preparation method, a composite protection plate and a battery pack. The composite material comprises the following components in parts by mass: 15-25 parts of silicon dioxide aerogel, 20-35 parts of a phase change microcapsule material, 20-30 parts of polyurethane foam and 8-12 parts of mica powder. Due to the combination of the components in the composite material, the composite material has good heat insulation performance, heat stability and buffering performance.

Description

Technical Field

[0001] The present application relates to the field of composite materials, and specifically, to composite materials and preparation methods, composite protection plates, and battery packs. Background Art

[0002] Electric vehicles are the main body of new energy vehicles, and power batteries are the core energy sources of electric vehicles. Lithium-ion power batteries have the advantages of high energy and power density and long service life, and are one of the most widely used chemical power sources for vehicles at present. The energy released by thermal runaway in high specific energy power batteries is more concentrated. Therefore, in the design and development process of high specific energy power batteries, it is necessary to ensure the thermal runaway safety performance of the batteries after mass production and adapt to the vibrations that may occur during vehicle movement.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. Summary of the Invention

[0004] In a first aspect of the present application, a composite material is proposed, including: 15 parts by mass - 25 parts by mass of silica aerogel, 20 parts by mass - 35 parts by mass of phase change microcapsule material, 20 parts by mass - 30 parts by mass of polyurethane foam, and 8 parts by mass - 12 parts by mass of mica powder. Thus, the composite material has good heat insulation performance, thermal stability and buffering performance.

[0005] In some embodiments, the enthalpy value of the phase change microcapsule material is 50 J / g - 250 J / g. Thus, the foregoing phase change microcapsule material component enables the composite material to have better thermal buffering performance.

[0006] In some embodiments, the thermal conductivity of the silica aerogel is 0.02 W / (m·K) - 0.06 W / (m·K). Thus, the foregoing silica aerogel component enables the composite material to have better heat insulation performance.

[0007] In some embodiments, the density of the silica aerogel is 0.05 g / cm 3 - 0.3 g / cm 3 . Thus, the foregoing silica aerogel component can reduce the density of the composite material and improve the heat insulation performance of the composite material.

[0008] In some embodiments, the average pore diameter of the silica aerogel is 20 nm - 50 nm. Thus, the foregoing silica aerogel component enables the composite material to have better heat insulation performance.

[0009] In some embodiments, the Dv50 particle size of the mica powder is 10 μm - 80 μm.

[0010] In some embodiments, the Dv50 particle size of the silica aerogel is 5 nm - 100 nm.

[0011] In some embodiments, the indentation hardness of the polyurethane foam is 3 kN - 5 kN. Thus, the aforementioned polyurethane foam component enables the composite material to have good shock absorption performance.

[0012] In some embodiments, the phase change microcapsule material includes a core material and a shell material, wherein the core material includes at least one of silicone oil, polyethylene wax emulsion, polypropylene wax emulsion, n-dodecane, calcium chloride hexahydrate, and paraffin wax. Thus, the phase change microcapsule material has good stability and temperature regulation effect.

[0013] In a second aspect of the present application, the present application provides a method for preparing the composite material, including: performing a first mixing process on the silica aerogel and mica powder to obtain a first mixture; performing a second mixing process on the phase change microcapsule material and the first mixture to obtain a second mixture, wherein the temperature of the second mixing process is 80°C - 100°C; performing a composite molding process on the polyurethane foam synthesis raw materials and the second mixture to obtain the composite material, wherein the polyurethane foam synthesis raw materials include polyether polyol, isocyanate, and foaming agent.

[0014] Thus, the method for preparing the composite material proposed by the present application can enable components with different functional characteristics to be fully mixed and their functionality to be fully exerted, so as to prepare a composite material that meets multi-dimensional functional requirements.

[0015] In some embodiments, the stirring speed of the first mixing process is 1200 rpm - 1800 rpm. Thus, the first mixture can be fully mixed.

[0016] In some embodiments, the composite molding process is carried out under vacuum conditions, and the vacuum degree of the vacuum conditions is 80 Pa - 150 Pa.

[0017] In some embodiments, the composite molding process includes at least one of hot pressing molding, extrusion molding, and injection molding. Thus, the shape requirements of different product designs can be met.

[0018] In a third aspect of the present application, the present application provides a composite protection board, which includes the composite material described above, or a composite material prepared by the method described above. The thickness of the composite protection board is 0.5 mm - 5 mm. Thus, the composite protection board has good mechanical properties, heat insulation properties, thermal stability, and buffering properties.

[0019] In a fourth aspect of the present application, a battery pack is proposed, which includes the composite material proposed in the present application, or the composite material prepared by the method proposed in the present application, or the composite protection plate proposed in the present application. Thus, the battery pack has good safety performance. Description of the Drawings

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0021] Figure 1 is a flowchart of a method for preparing a composite material in an embodiment of the present application;

[0022] Figure 2 is a schematic structural diagram of a battery in an embodiment of the present application;

[0023] Figure 3 is a schematic structural diagram of a battery pack in an embodiment of the present application;

[0024] Figure 4 is a schematic structural diagram of a battery pack in an embodiment of the present application.

[0025] Description of the Reference Numerals:

[0026] 1 Composite material protection and isolation layer; 2 Module protection cover; 3 Pressure relief channel. Detailed Description of the Embodiments

[0027] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, but there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where the detailed descriptions of well-known matters are omitted and the repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0028] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; unless otherwise specified, the numerical values of the various parameters mentioned in the present application can be measured by various commonly used measurement methods in the art (for example, they can be tested according to the methods given in the embodiments of the present application).

[0029] The terms "including" and "having" and any variations thereof in the specification and claims of the present application are open expressions, that is, including the content specified in the present application, but not excluding other aspects.

[0030] In the description of the present application, all the numbers disclosed herein are approximate values, whether or not words such as "about" or "approximate" are used. The numerical value of each number may have a difference of less than 10% or a reasonable difference considered by those skilled in the art, such as a difference of 1%, 2%, 3%, 4% or 5%.

[0031] The "ranges" disclosed in the present application are defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the specific range. The ranges defined in this way can include or exclude the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4 and 2 - 5. In the present application, unless otherwise specified, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" are fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when it is stated that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0032] If there is no special instruction, all the embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0033] If there is no special instruction, all the technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0034] When the power battery system undergoes high-rate charge and discharge, heat is generated and accumulates continuously in the battery, leading to an increase in battery temperature, which affects the battery life and stability. The vibration during vehicle driving can also damage the internal structure of the battery pack, thereby affecting the reliability and safety of the battery. Some battery monomers inside the battery pack may form local high-temperature hot spots due to the aforementioned mechanical or thermal incentives, which may further cause the surrounding monomer batteries to experience thermal runaway and spread within the battery pack. Although a cooling system can be designed inside the battery system to dissipate heat from the battery, when the charge and discharge rate is too high or the battery encounters a collision, etc., the aforementioned phenomenon of a sharp rise in the local battery temperature may still occur. The composite material proposed in this application is applied between battery cells and in the module protective cover to achieve efficient heat insulation, temperature control, and shock absorption protection for the entire battery pack, while improving the safety, structural stability, and comprehensive electrical performance of the battery pack.

[0035] In the first aspect of this application, a composite material is proposed, including: 15 parts by mass - 25 parts by mass of silica aerogel, 20 parts by mass - 35 parts by mass of phase change microcapsule material, 20 parts by mass - 30 parts by mass of polyurethane foam, and 8 parts by mass - 12 parts by mass of mica powder.

[0036] The composite material proposed in this application has multi-faceted composite functions with high integration and good comprehensiveness. Among the components of the composite material, silica aerogel has a porous structure with a high specific surface area, and can also achieve a low thermal conductivity at high temperatures, having excellent heat insulation performance. Mica powder has high heat resistance and heat insulation properties, which can improve the heat insulation performance and thermal stability of the composite material. The phase change microcapsule material can absorb heat by the phase change of the core material to achieve temperature regulation. In the structure of the composite material, the particle sizes of silica aerogel and mica powder are small, and the phase change microcapsule material is wrapped by the composite structure of silica aerogel and mica powder. There are physical adsorption, chemical bonding and other interactions between the shell material of the microcapsule material and the surfaces of silica aerogel and mica powder, making the composite between them have a certain strength. At the same time, the phase change microcapsule material is effectively protected in the composite material system containing polyurethane foam, which is beneficial to reducing the structural damage of the phase change microcapsule material caused by the impact and shock of the composite material, and is beneficial to the stable performance of the phase change function of the phase change microcapsule material. The heat insulation performance of silica aerogel and the thermal stability enhancement function of mica powder in the composite material cooperate with each other, which can slow down the structural damage of the phase change microcapsule material caused by the drastic change of the external environmental temperature, and effectively control the chain reaction caused by the rapid diffusion of heat. The porous structure of polyurethane foam can absorb mechanical vibration, has good elasticity, and can coat and accommodate other components, having good miscibility. The foregoing components are mixed in the foregoing parts by mass, so that the components of the composite material can stably and well achieve functional composite. The combination of the foregoing components in the composite material makes the composite material have good heat insulation performance, thermal stability and buffering performance due to the complementary microstructure, synergistic surface properties, chemical bond action and interface action.

[0037] In some embodiments, the silica aerogel and the mica powder are attached to the surface of the phase change microcapsule to form a heat insulation structure; the polyurethane foam coats the heat insulation structure to form the composite material.

[0038] In some embodiments, the rebound rate of the composite material is 60%-80%. Under the combined action of polyurethane foam and other components in the composite material, the rebound rate is controlled within the foregoing range. After being mechanically impacted, it undergoes a certain degree of elastic deformation, consumes part of the energy, and rebounds to play a role in buffering and shock absorption, and can continuously play the role of shock absorption. Thus, the composite material has good shock absorption performance.

[0039] In some embodiments, the enthalpy value of the phase change microcapsule material is 50 J / g - 250 J / g. When the enthalpy value of the phase change microcapsule material is within the foregoing range, using the mass parts proposed in this application as the components of the composite material can improve the heat storage capacity per unit mass of the composite material and slow down the temperature change of the composite material caused by heating. Thus, including the foregoing phase change microcapsule material component enables the composite material to have good thermal buffering performance.

[0040] As an example, the enthalpy value of the phase change microcapsule material is 50 J / g, 70 J / g, 90 J / g, 100 J / g, 110 J / g, 130 J / g, 150 J / g, 170 J / g, 190 J / g, 200 J / g, 220 J / g, 240 J / g, 250 J / g.

[0041] In some embodiments, the thermal conductivity of the silica aerogel is 0.02 W / (m·K) - 0.06 W / (m·K). When the silica aerogel is within the foregoing range, the heat transfer through the composite material can be reduced. Thus, including the foregoing silica aerogel component enables the composite material to have good heat insulation performance and reduces the occurrence of thermal runaway caused by local heat diffusion in the battery pack.

[0042] In some embodiments, the density of the silica aerogel is 0.05 g / cm 3 - 0.3 g / cm 3 . When the density of the silica aerogel is within the foregoing range, it has a high specific strength and excellent heat insulation performance. Using the silica aerogel according to the mass parts proposed in this application as the component of the composite material can reduce the mass per unit volume of the composite material and improve the heat insulation performance of the composite material. Thus, including the foregoing silica aerogel component can reduce the density of the composite material, reduce the weight of the components prepared from the composite material, and improve the heat insulation performance of the composite material.

[0043] In some embodiments, the average pore diameter of the silica aerogel is 20 nm - 50 nm. The pores in the silica aerogel with the foregoing pore diameters have relatively static gas flow, and heat transfer occurs through the conduction of the pore walls, which limits the heat transfer. Thus, including the foregoing silica aerogel component enables the composite material to have good heat insulation performance.

[0044] In some embodiments, the Dv50 particle size of the mica powder is 10 μm - 80 μm. When the Dv50 particle size of the mica powder is within the foregoing range, the mica powder and the silica aerogel can form a composite structure, which can achieve a good heat insulation effect. It is also beneficial to form a structural composite with the phase change microcapsule material and be wrapped by polyurethane foam, enabling the composite material to exhibit good heat insulation performance and shock absorption performance.

[0045] In some embodiments, the Dv50 particle size of the silica aerogel is 5 nm - 100 nm. When the Dv50 particle size of the silica aerogel is within the foregoing range, the silica aerogel can form a composite structure with mica powder. The silica aerogel has a porous material structure and can block the conduction of heat in the composite material.

[0046] In some embodiments, the indentation hardness of the polyurethane foam is 3 kN - 5 kN. When the indentation hardness of the polyurethane foam is within the foregoing range, it has good load-bearing capacity and can play a good blocking role under mechanical actions such as extrusion. Thus, including the foregoing polyurethane foam component enables the composite material to have good shock absorption performance.

[0047] In some embodiments, the phase change microcapsule material includes a core material and a shell material, wherein the core material includes at least one of silicone oil, polyethylene wax emulsion, polypropylene wax emulsion, n-dodecane, calcium chloride hexahydrate, and paraffin. The phase change microcapsule material having the foregoing core material can absorb heat and reduce the temperature change of the composite material itself after being heated. Thus, the phase change microcapsule material has good stability and temperature regulation effect, and further enables the composite material to have good heat regulation effect.

[0048] In some embodiments, the shell material includes at least one of TiO2, SiO2, and Al2O3. Thus, the phase change microcapsule material has good stability and applicability.

[0049] In some embodiments, the silicone oil includes dimethyl silicone oil.

[0050] In some embodiments, the viscosity of the silicone oil is 50 cSt - 500 cSt, and the melting point is -50 °C to -40 °C.

[0051] In some embodiments, the number average molecular mass of the polyethylene wax emulsion is 2000 - 5000, and the number average molecular mass of the polypropylene wax emulsion is 3000 - 6000.

[0052] In some embodiments, the enthalpy value of the polyethylene wax emulsion is 150 J / g - 200 J / g, and the enthalpy value of the polypropylene wax emulsion is 180 J / g - 220 J / g.

[0053] In the second aspect of the present application, the present application proposes a method for preparing the composite material, including:

[0054] S1: Perform a first mixing process on the silica aerogel and mica powder to obtain a first mixture;

[0055] The silica aerogel has a porous structure with nanoscale pores. During the first mixing process, mica powder is filled in the pores of the silica aerogel or adheres to its surface, enabling the two to support each other at the microstructural level. This complementarity at the microstructural level forms a stable basic structure, enhancing the binding stability between them from a physical aspect and facilitating the exertion of the functional specificities of both, reducing the impact on the material properties during subsequent preparation processes. Moreover, there are active groups and electrostatic interactions on the surfaces of the silica aerogel and mica powder, and these interactions are conducive to the formation of relatively stable aggregates after mixing, reducing the separation tendency of particles, thereby forming a stable first mixture after the first mixing process.

[0056] In some embodiments, the stirring speed of the first mixing process is 1200 rpm - 1800 rpm. Thus, the first mixture can be fully mixed.

[0057] In some embodiments, the time of the first mixing process is 15 min - 20 min.

[0058] S2: Perform a second mixing process on the phase change microcapsule material and the first mixture to obtain a second mixture, wherein the temperature of the second mixing process is 80°C - 100°C;

[0059] Performing the second mixing process within the temperature range of 80°C - 100°C enables the phase change microcapsule material to be in a suitable processing state. The temperature conditions within the aforementioned temperature range endow the phase change microcapsule material with good fluidity during the second mixing process. Mixing under higher fluidity results in less mixing resistance, facilitating full contact with the first mixture.

[0060] In some embodiments, the time of the second mixing process is 20 min - 25 min.

[0061] S3: Perform a composite molding process on the polyurethane foam synthesis raw materials and the second mixture to obtain the composite material, wherein the polyurethane foam synthesis raw materials include polyether polyol, isocyanate, and foaming agent.

[0062] Polyether polyols, isocyanates, foaming agents and other raw materials for polyurethane foam synthesis undergo chemical reactions during the composite molding process to form polyurethane foam. During the reaction, the newly formed polyurethane foam fills the complex pore structure composed of silica aerogel, mica powder and phase change microcapsules. This filling effect physically strengthens the entire system and reduces the movement and separation of each component. In addition, during the reaction formation of polyurethane foam, chemical bonding and interfacial interactions occur between the polymer molecular chains and the surfaces of silica aerogel, mica powder, and the shell material of the phase change microcapsule material. For example, isocyanate groups can react with active groups such as hydroxyl groups on the surface of silica aerogel. The aforementioned interactions enable the polyurethane foam to be tightly combined with the components it encapsulates to form a stable composite material as a whole. The foaming process of the polyurethane foam forms a uniform pore structure inside the composite material, which synergistically with the porous structure of the silica aerogel to further enhance the heat insulation function; the formation of a uniform pore structure inside the composite material also cooperates with the temperature regulation function of the phase change microcapsule material to achieve a better thermal management effect.

[0063] Therefore, in the method for preparing the composite material proposed in this application, during the mixing process at different stages, the process conditions of different mixing treatment steps are designed so that each component can fully exert its own material properties. Through physical filling, adsorption and chemical bonding between different materials, an intertwined and encapsulated organizational structure is formed. The temperature condition setting during the preparation process can promote good contact between different components in the composite material, and the chemical reaction during the processing is beneficial to the filling of the polyurethane foam in the pores of the composite material and the strengthening of the composite material system, which is beneficial to the cooperation of the functions exerted by different components in a stable structure, and realizes the mutual cooperation of multiple functions such as heat insulation, phase change and strengthening.

[0064] In some embodiments, the composite molding treatment includes mixing the polyurethane foam synthesis raw materials with the second mixture, and the mixing speed is 800 rpm - 1000 rpm.

[0065] In some embodiments, the mixing time is 20 min - 25 min.

[0066] In some embodiments, the composite molding treatment is carried out under vacuum conditions, and the vacuum degree of the vacuum conditions is 80 Pa - 150 Pa.

[0067] In some embodiments, the composite molding treatment includes at least one of hot pressing molding, extrusion molding, and injection molding. Thus, the shape requirements of different product designs can be met.

[0068] In some embodiments, the composite molding process includes hot pressing, the temperature of the hot pressing is 150°C - 200°C, and the pressure of the hot pressing is 10 MPa - 20 MPa. Thus, the composite material can be prepared into different shapes through mold design to meet the usage requirements.

[0069] Reference Figure 1 , the method for preparing the composite material proposed in this application can enable components with different functional characteristics to be fully mixed and their functionality to be fully exerted, so as to prepare a composite material that meets multi-dimensional functional requirements.

[0070] In some embodiments, before the first mixing process, the silica aerogel and mica powder are subjected to screening treatment.

[0071] In the third aspect of this application, a composite protection board is proposed. The composite protection board includes the composite material described above, or the composite material prepared by the method described above. The thickness of the composite protection board is 0.5 mm - 5 mm. Thus, the composite protection board has good mechanical properties, heat insulation properties, thermal stability and buffering properties, and has a relatively light self-weight.

[0072] In some embodiments, reference can be made to Figure 2 , the composite material board can be the composite material protection isolation layer 1 of the battery pack. Thus, during the assembly of the battery module, the composite material protection isolation layer 1 is placed between the battery cells and between the battery cell and the end plate, and is fixed by means of adhesives or mechanical fixation to ensure that it does not move or fall off during use, thereby achieving the effects of heat insulation and shock absorption.

[0073] In the fourth aspect of this application, a battery pack is proposed, including the composite material proposed in this application, or the composite material prepared by the method proposed in this application, or the composite protection board proposed in this application. Thus, the battery pack has good safety performance.

[0074] In some embodiments, in the battery pack, reference can be made to Figure 3 and Figure 4 , the composite material can be the module protection cover 2 of the battery pack. Thus, a pressure relief channel 3 is provided in the design of the module protection cover 2. When a thermal safety problem occurs in the battery, causing the battery to erupt at high temperature, the module protection cover 2 can direct the hot gas and flame out, avoiding the further expansion of thermal runaway, and at the same time effectively preventing the electrical harness from catching fire, achieving a good effect of thermal and electrical separation.

[0075] The solutions of the present application will be described below through specific embodiments. It should be noted that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those without specific techniques or conditions noted in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0076] Example 1

[0077] S1: Perform a first mixing treatment on 15 parts by mass of silica aerogel and 8 parts by mass of mica powder in a high-speed mixer at a stirring speed of 1200 rpm for 15 min to obtain a first mixture;

[0078] S2: Preheat 20 parts by mass of the phase change microcapsule material with the core material being polyethylene wax emulsion, and perform a second mixing treatment with the first mixture obtained in S1 at a temperature of 90 °C for 20 min to obtain a second mixture;

[0079] S3: Mix 20 parts by mass of the polyurethane foam synthesis raw materials, including polyether polyol, isocyanate, and foaming agent, with the second mixture obtained in S2 at a mixing speed of 900 rpm for 22 min. Add the mixed material into a mold, perform hot pressing at 170 °C and 15 MPa for 35 min, cool and demold to obtain a composite material.

[0080] Example 2

[0081] Example 2 is consistent with Example 1, except that 20 parts by mass of silica aerogel, 10 parts by mass of mica powder, 25 parts by mass of the phase change microcapsule material, and 25 parts by mass of the polyurethane foam synthesis raw materials are used.

[0082] Example 3

[0083] Example 3 is consistent with Example 1, except that 22 parts by mass of silica aerogel, 11 parts by mass of mica powder, 30 parts by mass of the phase change microcapsule material, and 28 parts by mass of the polyurethane foam synthesis raw materials are used.

[0084] Example 4

[0085] Example 4 is consistent with Example 1, except that 18 parts by mass of silica aerogel, 9 parts by mass of mica powder, 28 parts by mass of the phase change microcapsule material, and 22 parts by mass of the polyurethane foam synthesis raw materials are used.

[0086] Example 5

[0087] Example 5 is consistent with Example 1, except that 25 parts by mass of silica aerogel, 12 parts by mass of mica powder, 32 parts by mass of phase change microcapsule material, and 26 parts by mass of polyurethane foam synthesis raw materials are used.

[0088] Comparative Example 1

[0089] Comparative Example 1 is consistent with Example 1, except that 5 parts by mass of silica aerogel are used.

[0090] Comparative Example 2

[0091] Comparative Example 2 is consistent with Example 1, except that 35 parts by mass of silica aerogel are used.

[0092] Comparative Example 3

[0093] Comparative Example 3 is consistent with Example 1, except that 10 parts by mass of phase change microcapsule material are used.

[0094] Comparative Example 4

[0095] Comparative Example 4 is consistent with Example 1, except that 45 parts by mass of phase change microcapsule material are used.

[0096] Comparative Example 5

[0097] Comparative Example 5 is consistent with Example 1, except that 10 parts by mass of polyurethane foam synthesis raw materials are used.

[0098] Comparative Example 6

[0099] Comparative Example 6 is consistent with Example 1, except that 35 parts by mass of polyurethane foam synthesis raw materials are used.

[0100] Comparative Example 7

[0101] Comparative Example 7 is consistent with Example 1, except that 5 parts by mass of mica powder are used.

[0102] Comparative Example 8

[0103] Comparative Example 8 is consistent with Example 1, except that 15 parts by mass of mica powder are used.

[0104] Testing method:

[0105] Thermal conductivity testing method: The steady-state heat flow meter method is used for testing. By installing a sensor capable of measuring the heat flux density on the sample, the heat flux density generated therefrom is measured to calculate the thermal conductivity.

[0106] Test method for phase change enthalpy value: Differential Scanning Calorimetry (DSC) is adopted. Through a DSC tester, the difference in heat flux density between the sample and the standard sample is measured, and the phase change enthalpy value of the sample is obtained by calculation.

[0107] Test method for vibration attenuation rate: The resonance bar method is used for testing. The composite material protective isolation layer 1 is suspended at a specific position from the end face. By adjusting the signal frequency output by the signal generator, the specimen is in a resonance state, the damping value is calculated, and the vibration attenuation rate is obtained.

[0108] Test method for compressive strength: The composite material is made into a standard cuboid specimen of 100mm×100mm×50mm. In an environment of 25°C, it is placed on a compressive strength testing machine and pressed at a loading rate of 5mm / min until the specimen is damaged. The maximum pressure is recorded, the strength is calculated, and the average value is taken.

[0109] Test results: See Table 1

[0110] Table 1

[0111]

[0112] It can be seen from Table 1 that:

[0113] Referring to the test results of Examples 1 - 5, the various components of the composite material act synergistically to achieve low thermal conductivity and excellent heat insulation performance; moderate phase change enthalpy value and good temperature regulation ability; high vibration attenuation rate and excellent shock absorption effect; appropriate compressive strength and mechanical strength meeting the requirements, and the comprehensive performance reaches the best balance, capable of meeting various protection requirements.

[0114] Referring to the test results of Comparative Example 1, the content of silica aerogel is lower than the range proposed in this application, resulting in an increase in thermal conductivity and a significant decrease in heat insulation performance. The phase change enthalpy value is normal. In the case of only having the temperature regulation ability, the composite material can absorb a certain amount of heat, but cannot effectively isolate the conduction of heat. The shock absorption performance and mechanical strength of the composite material also do not reach the ideal level.

[0115] Referring to the test results of Comparative Example 2, the content of silica aerogel is higher than the range proposed in this application, resulting in a significant increase in cost, too low thermal conductivity, a decrease in the toughness of the composite material, the composite material becoming brittle, and an improvement in mechanical strength, but the overall performance is unbalanced.

[0116] Referring to the test results of Comparative Example 3, the content of phase change microcapsule material is lower than the range proposed in this application, resulting in a significant decrease in the phase change enthalpy value and a serious shortage of temperature regulation ability, affecting the comprehensive performance of the composite material.

[0117] Referring to the test results of Comparative Example 4, it can be seen that when the content of the phase change microcapsule material is higher than the range proposed in this application, it can lead to difficulties in the mutual combination of the components of the composite material to form a stable structure, resulting in a decrease in the stability of the composite material, a decrease in the mechanical strength of the composite material, and insignificant improvement in other properties, while increasing the cost.

[0118] Referring to the test results of Comparative Example 5, it can be seen that when the content of the shock-absorbing material is lower than the range proposed in this application, the shock-absorbing effect is significantly reduced, the vibration attenuation rate is significantly insufficient, and the composite material cannot exert an effective buffering effect.

[0119] Referring to the test results of Comparative Example 6, it can be seen that when the content of the shock-absorbing material is higher than the range proposed in this application, the structure of the composite material lacks support, the structural stability of the composite material decreases, and the heat insulation performance and temperature regulation ability are reduced.

[0120] Referring to the test results of Comparative Example 7, it can be seen that when the content of mica powder is lower than the range proposed in this application, the heat insulation and high-temperature resistance performance of the composite material are significantly weakened, affecting the comprehensive protection performance of the composite material.

[0121] Referring to the test results of Comparative Example 8, it can be seen that when the content of mica powder is higher than the range proposed in this application, the processing difficulty of the composite material increases, the cost increases, the improvement effect on the comprehensive performance such as heat insulation and shock absorption is not obvious, and the material toughness of the composite material is reduced.

[0122] In the description of this application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. The "first feature" and "second feature" may include one or more of such features.

[0123] In the description of this application, "A and / or B" may include the case of A alone, the case of B alone, and any one of the cases of A and B, where A and B are only for illustration and may be any technical features connected by "and / or" in this application.

[0124] In this application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special description, all steps of this application can be carried out in sequence or randomly, and preferably in sequence. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) carried out in sequence, or may also include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), indicating that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or may also include steps (a), (c), and (b), or may also include steps (c), (a), and (b), etc.

[0125] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same composition and the same effect within the scope of the technical solution of this application are included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A composite material, characterized in that: include: 15-25 parts by mass of silica aerogel, 20-35 parts by mass of phase change microcapsule material, 20-30 parts by mass of polyurethane foam, and 8-12 parts by mass of mica powder.

2. The composite material according to claim 1, characterized in that The enthalpy value of the phase change microcapsule material is 50 J / g-250 J / g.

3. The composite material according to claim 1, characterized in that The thermal conductivity of the silica aerogel is 0.02W / (m·K)-0.06W / (m·K); and / or, The density of the silica aerogel is 0.05 g / cm 3 -0.3g / cm 3 and / or, The average pore size of the silica aerogel is 20nm-50nm.

4. The composite material according to claim 1, characterized in that The Dv50 particle size of the mica powder is 10 μm-80 μm, and / or, The Dv50 particle size of the silica aerogel is 5nm-100nm.

5. The composite material according to claim 1, characterized in that The indentation hardness of the polyurethane foam is 3kN-5kN.

6. The composite material according to claim 2, characterized in that The phase-change microcapsule material comprises a core material and a shell material, wherein the core material comprises at least one of silicone oil, polyethylene wax emulsion, polypropylene wax emulsion, n-dodecane, calcium chloride hexahydrate, and paraffin.

7. A method for preparing the composite material according to any one of claims 1 to 6, characterized in that: include: Performing a first mixing process on the silica aerogel and the mica powder to obtain a first mixture; Performing a second mixing process on the phase change microcapsule material and the first mixture to obtain a second mixture, wherein the temperature of the second mixing process is 80° C.-100° C.; The polyurethane foam synthesis raw material and the second mixture are subjected to composite molding treatment to obtain the composite material, wherein the polyurethane foam synthesis raw material includes polyether polyol, isocyanate and foaming agent.

8. The method according to claim 7, characterized in that The stirring speed of the first mixing process is 1200 rpm-1800 rpm; and / or, The composite molding process is carried out under vacuum conditions, and the vacuum degree of the vacuum conditions is 80Pa-150Pa; and / or, The composite molding process includes at least one of hot pressing molding, extrusion molding, and injection molding.

9. A composite protective plate, characterized in that: The composite protective plate comprises the composite material described in any one of claims 1 to 6, or a composite material prepared by the method described in claim 7 or 8, and the thickness of the composite protective plate is 0.5 mm to 5 mm.

10. A battery pack, characterized in that: It comprises the composite material described in any one of claims 1 to 6, or the composite material prepared by the method described in claim 7 or 8, or the composite protective plate described in claim 9.

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