Silicon-based intrinsic flame-retardant phase change material, preparation method and application thereof

Abstract

This invention relates to the field of battery thermal management technology, and more particularly to a silicon-based intrinsically flame-retardant phase change material, its preparation method, and its application. The invention provides a silicon-based intrinsically flame-retardant phase change material, the raw materials for which include an intrinsic flame-retardant material, a supporting framework, and a thermal conductivity enhancer; the raw materials for preparing the intrinsically flame-retardant material include a reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate; the reversible phase change component is a fatty alcohol. The silicon-based intrinsically flame-retardant phase change material exhibits excellent flame-retardant performance and is also environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, and in particular to a silicon-based intrinsic flame-retardant phase change material, its preparation method, and its application. Background Technology

[0002] Thermal management plays a crucial role in optimizing the performance and sustainability of energy storage and power equipment. Lithium-ion batteries (LiBs) are widely used in these fields due to their advantages such as high specific energy density, low self-discharge rate, and long cycle life. However, their performance, lifespan, and reliability are closely related to operating temperature. Excessively high temperatures inevitably lead to capacity and power degradation, as well as lifespan decline. If heat cannot be dissipated in time and continues to accumulate, it may even lead to thermal runaway, resulting in a series of secondary disasters such as fires or explosions. Therefore, designing an efficient battery thermal management system (BTMS) is crucial for energy storage and power systems built using LiBs.

[0003] BTMS (Body Temperature Management Systems) are mainly classified into three types: active thermal management, such as air / liquid (AC / LC) cooling; passive thermal management, such as phase change material (PCM) cooling and heat pipe cooling; and hybrid thermal management, which combines the above active and passive types. Active BTMS requires heat dissipation through electrical components such as fans and pumps, which inevitably increases cost, manufacturing difficulty, and complexity. In recent years, research on PCM-based passive cooling has increased significantly in electronic and battery thermal management. Compared with traditional LC and AC cooling, PCM cooling has advantages such as high heat storage density and low energy consumption. During the melting process, the phase change material can absorb a large amount of heat generated during battery charging and discharging, keeping the battery module temperature relatively constant.

[0004] Generally, phase change materials can be divided into inorganic and organic types. Despite a lot of work, inorganic phase change materials are not suitable for BTMS that require thousands of endothermic and exothermic cycles due to their defects such as phase separation and large supercooling. Organic phase change materials are considered more suitable for BTMS because they have better stability. A lot of research has focused on preparing composite phase change materials (CPCMs) through various methods to overcome the defects of organic phase change materials. For example, carbonaceous or metallic materials are physically mixed to enhance thermal conductivity

[25] ; polymer skeletons are constructed as support frames to ensure their mechanical stability and prevent leakage, etc.

[0005] Most importantly, the flammability of organic phase change materials (PCMs) can pose potential safety hazards. A common solution is to physically incorporate large amounts of flame retardants into the PCMs to enhance their flame retardant properties. Anabel et al. (A. Palacios, A. De Gracia, L. Haurie, LF Cabeza, AI Fernández, C. Barreneche, Study of the Thermal Properties and the Fire Performance of Flam Retardant-Organic PCM Bulk Form, Materials, (2018).) investigated the effects of various flame retardant contents on the flame retardant properties of PCMs. The results showed that the flame retardant properties of the prepared CPCMs were significantly improved when 50 wt% hydrotalcite or magnesium hydroxide was added as a flame retardant. Zhang et al. (P. Zhang, L. Song, H. Lu, J. Wang, Y. Hu, Theinfluence of expanded graphite on thermal properties for paraffin / highdensity polyethylene / chlorinated paraffin / antimony trioxide as a flameretardant phase change material, Energy Conversion and Management, (2010)) incorporated a large amount of flame retardant, such as antimony trioxide, to improve the flame retardant properties of CPCM, but the latent heat was inevitably reduced by ~50%. Clearly, while the above-mentioned method of physically mixing a large amount of flame retardant can effectively and significantly improve flame retardant properties, it inevitably reduces the thermal properties of the resulting CPCM. On the other hand, most flame retardants are usually solid, and therefore have poor compatibility with molten phase change materials. It is difficult to achieve completely uniform dispersion during physical mixing. Moreover, many flame retardants release toxic gases or corrosive fumes during combustion. For example, during combustion, common tetrabromobisphenol type flame-retardant epoxy resins release toxic gases such as hydrogen bromide, tetrabromodibenzo-p-dioxin, and tetrabromodibenzofuran. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a silicon-based intrinsic flame-retardant phase change material, its preparation method and application, wherein the silicon-based intrinsic flame-retardant phase change material has excellent flame-retardant effect and is also green and environmentally friendly.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a silicon-based intrinsic flame-retardant phase change material, the raw materials for which include intrinsic flame-retardant material, supporting framework and thermal conductivity enhancer;

[0009] The raw materials for preparing the intrinsic flame retardant material include a reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate.

[0010] The reversible phase transition component is a fatty alcohol.

[0011] Preferably, the reversible phase change component includes one or more of tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and eicosyl alcohol.

[0012] Preferably, the thermal conductivity enhancer includes one or more of expanded graphite, biochar, carbon black, carbon fiber, carbon nanotubes, and graphene.

[0013] Preferably, the material of the supporting skeleton includes expanded graphite, epoxy resin, or low-density polyethylene;

[0014] The density of the low-density polyethylene is 0.910~0.940 g / cm³. 3 .

[0015] Preferably, the molar ratio of the reversible phase change component to 3-isocyanate-propyltrimethoxysilane is 1:1;

[0016] The total mass ratio of the reversible phase change component and 3-isocyanate-propyltrimethoxysilane to the mass ratio of dibutyltin dilaurate is 200:1.

[0017] Preferably, the mass ratio of the intrinsic flame retardant material, the supporting skeleton, and the thermal conductivity enhancer is (75~92):(3~20):(2~5).

[0018] This invention also provides a method for preparing the silicon-based intrinsic flame-retardant phase change material described in the above technical solution, comprising the following steps:

[0019] The molten reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate are first mixed and then subjected to an addition reaction to obtain an intrinsic flame retardant material.

[0020] The intrinsic flame-retardant material, the supporting skeleton, and the thermal conductivity enhancer are mixed to obtain a slurry.

[0021] The slurry is solidified to obtain the silicon-based intrinsic flame-retardant phase change material.

[0022] Preferably, the addition reaction is carried out under stirring conditions;

[0023] The stirring temperature was 80℃, the rotation speed was 300 rpm, and the stirring time was 24 hours.

[0024] Preferably, when the material of the supporting skeleton is epoxy resin, the second mixing process is to mix the intrinsic flame retardant material, epoxy resin A glue and thermal conductivity enhancer, and then add epoxy resin B glue to obtain a slurry.

[0025] The present invention also provides the application of the silicon-based intrinsic flame-retardant phase change material described in the above technical solution or the silicon-based intrinsic flame-retardant phase change material prepared by the preparation method described in the above technical solution in the field of battery thermal management.

[0026] This invention provides a silicon-based intrinsic flame-retardant phase change material. The raw materials include an intrinsic flame-retardant material, a supporting framework, and a thermal conductivity enhancer. The raw materials for preparing the intrinsic flame-retardant material include a reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate. The reversible phase change component is a fatty alcohol. In this invention, the reversible phase change component and 3-isocyanate-propyltrimethoxysilane react to prepare a silyl-modified phase change material, which is then combined with the supporting framework and the thermal conductivity enhancer to constitute a silicon-based intrinsic flame-retardant phase change material. On the one hand, the silyl-modified phase change material retains the phase change energy storage function; on the other hand, the silyl groups generate silica particles during combustion. These particles, together with the supporting framework and the thermal conductivity enhancer, achieve gas-solid two-phase flame retardancy, providing a new approach to solving the phase separation and agglomeration phenomena of traditional solid flame retardants in liquid phase change materials, and demonstrating its potential for practical application.

[0027] Compared with existing phase change materials applicable to battery thermal management, the silicon-based intrinsically flame-retardant phase change material of this invention has the following advantages:

[0028] 1) The silicon-based intrinsic flame-retardant phase change material of the present invention can undergo reversible cyclic heat absorption between 30 and 45°C (i.e., thermal management and temperature control of the battery under normal operating conditions).

[0029] 2) The silicon-based intrinsic flame-retardant phase change material described in this invention can also absorb a large amount of heat generated by the battery before thermal runaway occurs, thus prolonging the time the battery is in the second stage of thermal runaway (a heat absorption function that other flame retardants such as melamine, ammonium polyphosphate, phosphorus-based flame retardants and nitrogen-based flame retardants do not possess).

[0030] 3) After the battery experiences thermal runaway, the silicon-based intrinsic flame-retardant phase change material of the present invention, due to its high flame retardancy, can also prevent the spread of flames, thereby reducing the safety risks after the battery experiences thermal runaway.

[0031] 4) The silicon-based intrinsic flame-retardant phase change material described in this invention is green and environmentally friendly, and the raw materials are widely available and low in cost. Attached Figure Description

[0032] Figure 1 The DSC curve of the intrinsic flame-retardant material described in Example 1;

[0033] Figure 2 The DSC curve of the composite phase change material described in Comparative Example 2;

[0034] Figure 3 The battery module assembled from the silicon-based intrinsic flame-retardant phase change material module of Example 1 and the composite phase change material module of Comparative Example 1 is shown as the temperature change curves during charging and discharging at 0.5C and 1C rates.

[0035] Figure 4 Temperature change curves of metal plates 1-5 in the simulated battery assembled in Example 1;

[0036] Figure 5 The temperature change curves of metal plates 1 to 5 in the simulated battery of Comparative Example 1 (only metal plate 1 is heated, and the other metal plates are not heated);

[0037] Figure 6 This is a physical image of the battery module and simulated battery being tested in the test case. Detailed Implementation

[0038] This invention provides a silicon-based intrinsic flame-retardant phase change material, the raw materials for which include intrinsic flame-retardant material, supporting framework and thermal conductivity enhancer;

[0039] The raw materials for preparing the intrinsic flame retardant material include a reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate.

[0040] The reversible phase transition component is a fatty alcohol.

[0041] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0042] In this invention, the reversible phase change component is a fatty alcohol, more preferably including one or more of tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and eicosyl alcohol. When the reversible phase change component is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the reversible phase change component can be hexadecyl alcohol, tetradecyl alcohol, or octadecyl alcohol.

[0043] In this invention, the material of the supporting skeleton preferably includes expanded graphite, epoxy resin, or low-density polyethylene; the density of the low-density polyethylene is preferably 0.910~0.940 g / cm³. 3 .

[0044] In this invention, the thermal conductivity enhancer preferably includes one or more of expanded graphite, biochar, carbon black, carbon fiber, carbon nanotubes, and graphene. When the thermal conductivity enhancer is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and any ratio can be used. In the embodiments of this invention, the thermal conductivity enhancer can be expanded graphite (i.e., in the embodiments of this invention, the expanded graphite serves as both a supporting framework material and a thermal conductivity enhancer).

[0045] In this invention, the molar ratio of the reversible phase change component to 3-isocyanate-propyltrimethoxysilane is preferably 1:1.

[0046] In this invention, the ratio of the total mass of the reversible phase change component and 3-isocyanate-propyltrimethoxysilane to the mass of dibutyltin dilaurate is preferably 200:1.

[0047] In this invention, the preferred mass ratio of the intrinsic flame retardant material, the supporting skeleton, and the thermal conductivity enhancer is (75~92):(3~20):(2~5), more preferably 75:20:5, 80:18:2, 80:17:3, 80:16:4, 80:15:5, 85:10:5, 85:11:4, 85:12:3, 85:13:2, 90:5:5, 90:6:4, 90:7:3, 90:8:2, 91:4:5, 91:5:4, 91:6:3, 91:7:2, 92:3:5, 92:4:4, 92:5:3, or 92:6:2. In embodiments of the present invention, when both the supporting skeleton and the thermal conductivity enhancer are expanded graphite, the mass ratio of the intrinsic flame retardant material to the total mass of the supporting skeleton and the thermal conductivity enhancer can be 92:8; when the supporting skeleton and the thermal conductivity enhancer are of different types, the mass ratio of the intrinsic flame retardant material, the supporting skeleton and the thermal conductivity enhancer can be 82:15:3 or 82:15:3.

[0048] This invention also provides a method for preparing the silicon-based intrinsic flame-retardant phase change material described in the above technical solution, comprising the following steps:

[0049] The molten reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate are first mixed and then subjected to an addition reaction to obtain an intrinsic flame retardant material.

[0050] The intrinsic flame-retardant material, the supporting skeleton, and the thermal conductivity enhancer are mixed to obtain a slurry.

[0051] The slurry is solidified to obtain the silicon-based intrinsic flame-retardant phase change material.

[0052] This invention involves mixing a molten reversible phase change component with 3-isocyanate-propyltrimethoxysilane and dibutyltin dilaurate in a first mixture and performing an addition reaction to obtain an intrinsic flame retardant material.

[0053] In this invention, the method for preparing the molten reversible phase change component preferably includes melting the reversible phase change component in an oil bath. In this invention, the melting temperature is preferably 80°C.

[0054] In this invention, the first mixing is preferably performed by simultaneously adding 3-isocyanate-propyltrimethoxysilane and dibutyltin dilaurate to the molten reversible phase change component; this invention does not impose any special limitations on the manner and process of addition, and any manner and process known to those skilled in the art can be used.

[0055] In this invention, the addition reaction is preferably carried out under stirring conditions; the stirring temperature is preferably 80°C; the stirring speed is preferably 300 rpm; and the stirring time is preferably 24 h.

[0056] After obtaining the intrinsic flame retardant material, the present invention mixes the intrinsic flame retardant material, the supporting skeleton and the thermal conductivity enhancer to obtain a slurry.

[0057] Before the second mixing, the present invention preferably includes melting the intrinsic flame retardant material; the present invention does not have any special limitations on the melting process, and any process known to those skilled in the art can be used.

[0058] In this invention, when the material of the supporting skeleton is epoxy resin, the second mixing process is to mix the intrinsic flame retardant material, epoxy resin A glue and thermal conductivity enhancer, and then add epoxy resin B glue to obtain a slurry.

[0059] In embodiments of the present invention, the second mixing process may involve adding expanded graphite in batches to the intrinsic flame-retardant material. The addition of the expanded graphite is preferably carried out under stirring conditions, with the stirring temperature preferably at 80°C, the stirring speed preferably at 600 rpm, and the stirring time preferably at 20 minutes. The present invention does not impose any special limitations on the batch addition process of the expanded graphite; any process described by those skilled in the art can be used.

[0060] After obtaining the slurry, the present invention solidifies the slurry to obtain the silicon-based intrinsic flame-retardant phase change material.

[0061] In this invention, the preferred method for the curing and molding process is to fill the slurry into a mold and then cool and solidify it. This invention does not impose any special limitations on the cooling and solidification process; any process well-known to those skilled in the art can be used.

[0062] This invention also provides the application of the silicon-based intrinsic flame-retardant phase change material described in the above-described technical solutions, or the silicon-based intrinsic flame-retardant phase change material prepared by the preparation method described in the above-described technical solutions, in the field of battery thermal management. This invention does not impose any special limitations on the methods for these applications; any methods well-known to those skilled in the art can be used.

[0063] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0064] Example 1

[0065] 60g of hexadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten hexadecyl alcohol;

[0066] 51.83 g of 3-isocyanopropyltrimethoxysilane and 0.5 wt% (percentage of dibutyltin dicarboxylate relative to the total mass of hexadecyl alcohol and 3-isocyanopropyltrimethoxysilane) were simultaneously added to the molten hexadecyl alcohol, and the mixture was reacted for 24 h at a temperature of 80 °C and a stirring speed of 300 rpm to obtain an intrinsic flame retardant material (the intrinsic flame retardant material is hexadecylaminopropyltrimethoxysilane).

[0067] After melting 92g of the intrinsic flame retardant material, 8g of expanded graphite was added in batches. The batch addition process was carried out under stirring conditions. The stirring temperature was 80℃, the stirring speed was 600rpm, and the time was 20min, to obtain a uniform slurry.

[0068] The uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a silicon-based intrinsic flame-retardant phase change material (denoted as SiHD / EG).

[0069] Figure 1 The DSC curve of the intrinsic flame-retardant material is given by... Figure 1 It is known that the latent heat of the intrinsic flame-retardant material is 115.1 J·g. -1 Modification of phase change materials by 3-isocyanate-propyltrimethoxysilane does not alter their phase change energy storage function.

[0070] Example 2

[0071] 60g of tetradecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten tetradecyl alcohol;

[0072] 58.05 g of 3-isocyanate-propyltrimethoxysilane and 0.05 wt% (percentage of dibutyltin dibutylsilicate relative to the total mass of tetradecyl alcohol and 3-isocyanate-propyltrimethoxysilane) were simultaneously added to the molten tetradecyl alcohol. The mixture was reacted for 24 h at 80 °C and 300 rpm with stirring to obtain an intrinsic flame retardant material (the intrinsic flame retardant material is tetradecylaminocarbamate-propyltrimethoxysilane).

[0073] After melting 92g of the intrinsic flame retardant material, 8g of expanded graphite was added in batches. The batch addition process was carried out under stirring conditions. The stirring temperature was 80℃, the stirring speed was 600rpm, and the time was 20min, to obtain a uniform slurry.

[0074] The uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a silicon-based intrinsic flame-retardant phase change material.

[0075] Example 3

[0076] 60g of octadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten octadecyl alcohol;

[0077] 46.48 g of 3-isocyanopropyltrimethoxysilane and 0.05 wt% (percentage of dibutyltin dicarboxylate relative to the total mass of cetyl alcohol and 3-isocyanopropyltrimethoxysilane) were simultaneously added to the molten cetyl alcohol. The mixture was reacted at 80 °C and 300 rpm for 24 h to obtain an intrinsic flame retardant material (the intrinsic flame retardant material is octadecylcarbamate propyltrimethoxysilane).

[0078] After melting 92g of the intrinsic flame retardant material, 8g of expanded graphite was added in batches. The batch addition process was carried out under stirring conditions. The stirring temperature was 80℃, the stirring speed was 600rpm, and the time was 20min, to obtain a uniform slurry.

[0079] The uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a silicon-based intrinsic flame-retardant phase change material.

[0080] Example 4

[0081] 60g of octadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten octadecyl alcohol;

[0082] 46.48 g of 3-isocyanopropyltrimethoxysilane and 0.05 wt% (percentage of dibutyltin dicarboxylate relative to the total mass of cetyl alcohol and 3-isocyanopropyltrimethoxysilane) were simultaneously added to the molten cetyl alcohol. The mixture was reacted at 80 °C and 300 rpm for 24 h to obtain an intrinsic flame retardant material (the intrinsic flame retardant material is octadecylcarbamate propyltrimethoxysilane).

[0083] After melting 82g of the intrinsic flame-retardant material, 15g of supporting skeleton (density 0.940g / cm³) was added in batches. 3 The batch addition process of low-density polyethylene and 3g of thermally conductive reinforcing agent (carbon fiber) is carried out under stirring conditions. The stirring temperature is 80℃, the stirring speed is 600rpm, and the time is 20min to obtain a uniform slurry.

[0084] The uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a silicon-based intrinsic flame-retardant phase change material.

[0085] Example 5

[0086] 60g of octadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten octadecyl alcohol;

[0087] 46.48 g of 3-isocyanopropyltrimethoxysilane and 0.05 wt% (percentage of dibutyltin dicarboxylate relative to the total mass of cetyl alcohol and 3-isocyanopropyltrimethoxysilane) were simultaneously added to the molten cetyl alcohol. The mixture was reacted at 80 °C and 300 rpm for 24 h to obtain an intrinsic flame retardant material (the intrinsic flame retardant material is octadecylcarbamate propyltrimethoxysilane).

[0088] Under the conditions of stirring at 80℃ and 600rpm, 82g of the intrinsic flame retardant material was melted, mixed with 7.5g of epoxy resin A and 3g of thermal conductivity reinforcing agent (carbon fiber), and then 7.5g of epoxy resin B was added. The mixture was stirred for 5 minutes to obtain a uniform slurry.

[0089] The uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a silicon-based intrinsic flame-retardant phase change material.

[0090] Comparative Example 1

[0091] 46g of hexadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten hexadecyl alcohol;

[0092] 8g of expanded graphite was added in batches to the molten cetyl alcohol. The batch addition process was carried out under stirring conditions. The stirring speed was 600 rpm and the time was 20 min to obtain a first uniform slurry.

[0093] 32g of ammonium polyphosphate and 14g of red phosphorus were added in batches to the first uniform slurry. The batch addition process was carried out under stirring conditions. The stirring speed was 900 rpm and the time was 30 min to obtain the second uniform slurry.

[0094] The second uniform slurry is poured into the corresponding mold and cooled to solidify, thus obtaining a composite phase change material (denoted as HD / APP / RP / EG).

[0095] Comparative Example 2

[0096] 46g of hexadecyl alcohol was placed in an oil bath at 80℃ and melted to obtain molten hexadecyl alcohol;

[0097] 32g of ammonium polyphosphate and 14g of red phosphorus were added in batches to the molten cetyl alcohol. The batch addition process was carried out under stirring conditions. The stirring speed was 900 rpm and the time was 30 min to obtain a second uniform slurry.

[0098] The second uniform slurry is poured into the corresponding mold, cooled and solidified to obtain a composite phase change material (denoted as HD / APP / RP).

[0099] Figure 2 The DSC curve of the composite phase change material is given by... Figure 2 It is known that the latent heat of the composite phase change material is 110.2 J·g. -1 Therefore, it can be seen that the heat storage capacity of Example 1 is higher than that of Comparative Example 1. At the same time, the thermal conductivity of Example 1 is higher than that of Comparative Example 2, which is 1.85 W / m·K and 1.56 W / m·K, respectively.

[0100] Test case

[0101] Using the methods of Example 1 and Comparative Example 1, the dimensions (length × width × height) were obtained as 90 × 90 × 65 mm. 3 A silicon-based intrinsic flame-retardant phase change material module (Example 1) and a composite phase change material module (Comparative Example 1) were constructed. Nine cylindrical holes with a diameter of 26 mm were drilled at equal intervals using a drilling machine. Nine 26650 cylindrical batteries were then embedded into the corresponding holes (see physical image). Figure 6 As shown in (a), the battery modules are assembled into a 3-series 3-parallel configuration for charge and discharge testing, and thermocouples are used to monitor temperature changes during the charge and discharge process.

[0102] Figure 3The figures show the temperature change curves of the battery module assembled from the silicon-based intrinsic flame-retardant phase change material module of Example 1 and the composite phase change material module of Comparative Example 1 at 0.5C and 1C charge / discharge rates. Here, a represents the temperature after one cycle of charge / discharge at 0.5C, b represents the temperature after one cycle of charge / discharge at 1C, c represents the temperature difference after one cycle of charge / discharge at 0.5C, and d represents the temperature difference after one cycle of charge / discharge at 1C. Figure 3 It can be seen that, regardless of whether it is 0.5C or 1C charge and discharge, the cooling effect of Example 1 is higher than that of Comparative Example 1. The reason may be that the physical addition of ammonium polyphosphate has low compatibility with red phosphorus flame retardant, which affects the heat storage effect.

[0103] Using the methods of Example 1 and Comparative Example 1, six pieces with dimensions of 140×100×655mm were obtained respectively. 3 After the silicon-based intrinsic flame-retardant phase change material plate (Example 1) and the composite phase change material plate (Comparative Example 1) were installed alternately with 5 metal plates for battery thermal runaway simulation test, the metal plates were used to simulate the battery (the actual picture is shown in Figure 6 (b)). The specific test process is as follows: the first metal plate is heated by DC power at a power of 200W, and the temperature changes of the 5 metal plates and the surrounding metal plates are monitored by thermocouples.

[0104] Figure 4 The temperature change curves of metal plates 1-5 in the simulated battery assembled in Example 1 (only metal plate 1 is heated, the other metal plates are not heated) are provided by... Figure 4 It can be seen that the highest temperature is significantly lower than 250℃;

[0105] Figure 5 The temperature change curves of metal plates 1-5 in the simulated battery of Comparative Example 1 (only metal plate 1 is heated, the other metal plates are not heated) are derived from... Figure 5 It can be seen that the highest temperature is above 250℃; combined with Figures 4-5 It can be seen that the temperatures of metal plates 1 to 5 in Example 1 (T1, T2, T3, T4 and T5 in sequence) are all lower than the temperatures of metal plates 1 to 5 in Comparative Example 1 (T1, T2, T3, T4 and T5 in sequence).

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silicon-based intrinsically flame-retardant phase change material, characterized in that, The raw materials for preparation include intrinsic flame retardant materials, supporting skeletons, and thermal conductivity enhancers; The raw materials for preparing the intrinsic flame retardant material include a reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate. The reversible phase transition component is a fatty alcohol; The molar ratio of the reversible phase change component to 3-isocyanate-propyltrimethoxysilane is 1:1; The total mass ratio of the reversible phase change component and 3-isocyanate-propyltrimethoxysilane to the mass ratio of dibutyltin dilaurate is 200:1; The mass ratio of the intrinsic flame-retardant material, the supporting skeleton, and the thermal conductivity enhancer is (75~92):(3~20):(2~5); The preparation method of the intrinsic flame-retardant material includes: The molten reversible phase change component, 3-isocyanate-based propyltrimethoxysilane, and dibutyltin dilaurate are first mixed and then subjected to an addition reaction to obtain an intrinsic flame retardant material.

2. The silicon-based intrinsically flame-retardant phase change material as described in claim 1, characterized in that, The reversible phase change component includes one or more of tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and eicosyl alcohol.

3. The silicon-based intrinsically flame-retardant phase change material as described in claim 1, characterized in that, The thermal conductivity enhancer includes one or more of expanded graphite, biochar, carbon black, carbon fiber, carbon nanotubes, and graphene.

4. The silicon-based intrinsically flame-retardant phase change material as described in claim 1, characterized in that, The supporting frame is made of expanded graphite, epoxy resin, or low-density polyethylene. The density of the low-density polyethylene is 0.910~0.940 g / cm³. 3 .

5. The method for preparing the silicon-based intrinsic flame-retardant phase change material according to any one of claims 1 to 4, characterized in that, Includes the following steps: The molten reversible phase change component, 3-isocyanate-propyltrimethoxysilane, and dibutyltin dilaurate are first mixed and then subjected to an addition reaction to obtain an intrinsic flame retardant material. The intrinsic flame-retardant material, the supporting skeleton, and the thermal conductivity enhancer are mixed to obtain a slurry. The slurry is solidified to obtain the silicon-based intrinsic flame-retardant phase change material.

6. The preparation method according to claim 5, characterized in that, The addition reaction is carried out under stirring conditions; The stirring temperature was 80℃, the rotation speed was 300 rpm, and the stirring time was 24 hours.

7. The preparation method according to claim 5, characterized in that, When the material of the supporting skeleton is epoxy resin, the second mixing process is to mix the intrinsic flame retardant material, epoxy resin A glue and thermal conductivity enhancer, and then add epoxy resin B glue to obtain a slurry.

8. The application of the silicon-based intrinsic flame-retardant phase change material according to any one of claims 1 to 4 or the silicon-based intrinsic flame-retardant phase change material prepared by the preparation method according to any one of claims 5 to 7 in the field of battery thermal management.

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