Heat-conducting flame-retardant material

Abstract

The invention relates to a heat-conducting flame-retardant material which is in a liquid state, a colloidal state or a semi-solid state and comprises the following components: silicon dioxide which accounts for 10-85wt% of the whole; a reactant, which has cross-linkability and foaming reactivity, and which is mixed with the silica; the catalyst is a temperature sensitization or photosensitization catalyst, and the catalyst is mixed with the reactant to trigger the foaming reaction of the reactant; the heat-conducting flame-retardant material has heat conductivity before the reactant is subjected to foaming reaction, and has flame retardance after the reactant is subjected to foaming reaction.

Description

Technical Field

[0001] The invention relates to a sealing material for explosion-proof and flame-retardant electronic components, and is particularly applicable to the coating of battery cores. Background Art

[0002] Thermally conductive flame retardant materials are materials that have the characteristics of preventing heat conduction and resisting the spread of fire. These materials are usually used in the fields of construction, industrial facilities, and transportation to improve fire safety and fire resistance. The prior art is directed to a thermal insulation composite material and its preparation method and application research. For example, the raw materials for preparing the thermal insulation composite material disclosed in Chinese Patent Publication No. CN116496628A include a substrate and a resin composition, and the resin composition includes the following components in parts by weight: 100 parts by weight of hydroxyl-terminated polysiloxane, 5-20 parts by weight of vinyl polysiloxane, 20-50 parts by weight of hydrogen-containing polysiloxane, 0.1-5 parts by weight of sulfonylhydrazide foaming agent, 0.1-1 parts by weight of drying agent, 1-20 parts by weight of metal hydride, and 5-50 parts by weight of silica aerogel. Through the component design and mutual compounding of the resin composition, the resin composition forms a cross-linked network structure and a uniform porous structure after curing and foaming, which gives the thermal insulation composite material excellent flame retardancy, low thermal conductivity, high temperature resistance and thermal insulation, and can fully meet the application in building materials, electrical appliances, chemical equipment, energy storage equipment, mechanical equipment or oil extraction.

[0003] Prior art studies have been conducted on a curable silicone composition, as disclosed in Taiwan Patent Publication No. TW202311437A, which has high thixotropy and can form a cured product exhibiting excellent refractive index and transparency. The above-mentioned problems are solved by a curable silicone composition comprising the following components: (A) an alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms per molecule; (C) 3% by mass or more of silica-titanium oxide composite oxide particles relative to the total mass of the composition; and (D) a curing catalyst.

[0004] A foaming agent is a chemical substance or additive used to make foam or vesicular materials. They are widely used in different industries and applications, and are usually used to change the density, structure and properties of materials. The prior art is directed to a study of an aerogel-modified heat-resistant rigid polyurethane foam plastic and a preparation method thereof. For example, as disclosed in Chinese Patent Publication No. CN109232850A, an aerogel composite heat-resistant flame retardant is dispersed in a polyurethane body to form a polyurethane foam material after modification. The composite heat-resistant flame retardant is a composite heat-resistant flame retardant formed by modifying an aerogel powder with a phosphate heat-resistant flame retardant. A composite heat-resistant flame retardant of modified aerogel is added to polyurethane foam (RPUF), and the composite heat-resistant flame retardant is evenly dispersed in the RPUF body, and after heating, curing and maturation, a heat-resistant, flame-retardant and low thermal conductivity rigid polyurethane foam is obtained. The RPUF modified by the present invention has a temperature resistance of 153°C, a thermal conductivity of less than 0.027W / m·K, a limiting oxygen index of greater than or equal to 32%, and a compressive strength of 0.39-0.40MPa.

[0005] The prior art is directed to a high-performance fire-retardant phenolic foam and a preparation method thereof. As disclosed in Chinese patent publication number CN111732814B, the high-performance fire-retardant phenolic foam comprises an inorganic flame retardant material, which is mixed with a phenolic resin, polyethylene glycol, an emulsifier and a foaming agent and then added with a curing agent to prepare the foam; wherein the inorganic flame retardant material is prepared by mixing aluminum hydroxide, cerium dioxide and silicon dioxide according to a ratio of 10 to 25: 5 to 10: 8 to 25, and a specific ratio of organic acid and inorganic acid is mixed (the ratio of organic acid to inorganic acid is 1: 3) as a curing agent, so that the prepared phenolic foam has a fire spread index of 0 and a smoke index reduced to 35. At the same time, the thermal conductivity is measured to be ≤0.023W / m·k. The high-performance fire-retardant phenolic foam has good thermal insulation performance and achieves a higher fire retardant effect.

[0006] Therefore, in the prior art, it is necessary to install a heat sink on the outside of the battery and cover the surface of the battery element with a heat dissipation coating to achieve the effect of battery heat dissipation. The heat dissipation structure is complex, and when a single battery pack is abnormal, the battery cannot be sealed and isolated to prevent the temperature from being transferred to other battery packs, resulting in poor safety in battery use. Summary of the invention

[0007] The present invention is a heat-conducting flame-retardant material, which is in a liquid state, a colloidal state or a semi-solid state, and includes: silicon dioxide, which accounts for 10-85%wt of the whole; a reactant, which has cross-linking and foaming reactivity, and the reactant is mixed with the silicon dioxide; and a catalyst, which is a temperature-sensitized or light-sensitized catalyst, and the catalyst is mixed with the reactant to trigger the foaming reaction of the reactant; the heat-conducting flame-retardant material has thermal conductivity before the reactant has a foaming reaction, and the reactant has flame retardancy after the foaming reaction. Wherein, the average particle size d of the silicon dioxide is 5nm-10μm. Wherein, the reactant starts the foaming reaction when the ambient temperature is greater than 130°C. Wherein, the reactant starts the foaming reaction when the ambient temperature is greater than 160°C, and the foaming reaction is completed in 30 seconds-5 minutes. Wherein, the silicon dioxide accounts for 80%wt of the whole before the reactant of the heat-conducting flame-retardant material has a foaming reaction, and the foaming time is 6 seconds to complete the reaction. Wherein, the reactant of the thermally conductive flame retardant material has a silicon dioxide content of 40%wt before the foaming reaction, and the foaming time is 4 seconds to complete the reaction. Wherein, the reactant of the thermally conductive flame retardant material is used for the coating of the battery core before the foaming reaction, as well as the coating material inside and outside the battery core shell. When the temperature reaches the reaction temperature of the reactant, the foaming reaction is started, and the reactant of the thermally conductive flame retardant material blocks the temperature transfer inside and outside the battery core after the foaming reaction. Wherein, the flame retardancy of the reactant of the thermally conductive flame retardant material after the foaming reaction is greater than the UL94 rating and can reach V0-5VA. Wherein, the overall thickness of the reactant of the thermally conductive flame retardant material after the foaming reaction is 600μm, and its thermal insulation temperature is greater than 800°C. The present invention has heat conduction, explosion-proof and flame retardant effects, and is particularly used for the coating of the battery core. The silicon dioxide material before foaming acts as a heat conductor, and can prevent the battery core from overheating and exploding before the foaming reaction. After foaming, the thermally conductive flame retardant material can block the temperature transfer of the battery core and prevent extended combustion. Its composition and foaming mechanism are different from the prior art, and its novelty, progress and practical benefits are undoubted. The technology, means and effects adopted by the present invention are described in detail below with a preferred embodiment and accompanying drawings. It is believed that the above-mentioned purpose, structure and characteristics of the present invention can be understood in depth and detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0009] Figure 1 A cross-sectional schematic diagram showing the thermally conductive flame-retardant material of the present invention filled between a battery core and a first metal packaging material; Figure 2 A cross-sectional schematic diagram showing the heat-conductive flame-retardant material of the present invention filled between a first metal packaging material and a second metal packaging material.

[0010] Description of Reference Numerals 101. Thermally conductive flame retardant materials; 201, battery core; 301, first metal packaging material; 302. Second metal packaging material. DETAILED DESCRIPTION

[0011] The following describes the implementation of the present invention through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0012] The invention discloses a heat-conducting flame-retardant material, which is in a liquid state, a colloidal state or a semi-solid state, and comprises: silicon dioxide, which accounts for 10-85%wt of the whole; a reactant, which has cross-linking and foaming reactivity, and is mixed with the silicon dioxide; and a catalyst, which is a temperature-sensitized or light-sensitized catalyst, and the catalyst is mixed with the reactant to trigger the foaming reaction of the reactant; the heat-conducting flame-retardant material has the characteristics that the reactant has heat conductivity before the foaming reaction, and has flame retardancy after the foaming reaction.

[0013] Wherein, the average particle size d of the silicon dioxide is 5nm-10μm. Wherein, the reactant starts the foaming reaction when the ambient temperature is greater than 130°C. Wherein, the reactant starts the foaming reaction when the ambient temperature is greater than 160°C, and the foaming reaction is completed in 30 seconds-5 minutes. Wherein, the silicon dioxide accounts for 80%wt of the whole before the reactant of the thermal conductive flame retardant material foams, and the foaming time is 6 seconds to complete the reaction. Wherein, the silicon dioxide accounts for 40%wt of the whole before the reactant of the thermal conductive flame retardant material foams, and the foaming time is 4 seconds to complete the reaction.

[0014] Wherein, the reactant of the thermally conductive flame retardant material is applied to the battery core coating and the inner and outer coating materials of the battery core shell before the foaming reaction; when the temperature reaches the reaction temperature of the reactant, the foaming reaction is started, and the reactant of the thermally conductive flame retardant material blocks the temperature transfer inside and outside the battery core after the foaming reaction. Wherein, the flame retardancy of the reactant of the thermally conductive flame retardant material after the foaming reaction is greater than the UL94 rating and can reach V0-5VA. Wherein, the overall thickness of the reactant of the thermally conductive flame retardant material after the foaming reaction is 600μm, and its thermal insulation temperature is greater than 800°C. The thermal insulation temperature test method is to heat one side of the thin sheet of the thermally conductive flame retardant material with an overall thickness of 600μm, and test the other side with a thermometer to see if there is a temperature rise.

[0015] In order to further understand the practical application scenarios of the present invention, the application of thermal conductivity and explosion-proof of battery core is given as an example. Figure 1The cross-sectional schematic diagram shows that the thermally conductive flame-retardant material of the present invention is filled between the battery core and the first metal package material, indicating that the thermally conductive flame-retardant material 101 of the present invention is filled between the battery core 201 and the first metal package material 301. The first metal package material 301 is an aluminum shell, aluminum foil or stainless steel shell, and the thermally conductive flame-retardant material 101 completely covers the battery core 201. When the battery core 201 is heated during normal use, the thermally conductive flame-retardant material 101 in the non-foamed state can fully dissipate the heat energy to achieve the heat dissipation and cooling effect of the battery core 201; and when the battery core 201 is abnormally heated, the reactant starts the foaming reaction when the ambient temperature is greater than 130°C, and the reaction is completed within a short foaming time of 30 seconds to 5 minutes. After foaming, the thermally conductive flame-retardant material 101 can block the temperature of the battery core 201 from being transmitted outward and prevent extended combustion. In other words, the single abnormal battery core 201 only smolders inside the foamed thermally conductive flame retardant material 101, and the foamed air chamber of the foamed thermally conductive flame retardant material 101 blocks the temperature transfer, so that the single abnormal battery core 201 will not continue to burn to other battery cores or other electronic components.

[0016] Figure 2 The cross-sectional schematic diagram shows that the heat-conducting flame-retardant material of the present invention is filled between the first metal package material and the second metal package material, indicating that the heat-conducting flame-retardant material 101 of the present invention is filled between the first metal package material 301 and the second metal package material 302. The first metal package material 301 and the second metal package material 302 are aluminum shells, aluminum foils or stainless steel shells, and the heat-conducting flame-retardant material 101 completely covers the second metal package material 302 on the periphery of the battery core 201. When the battery core 201 is heated during normal use, the heat-conducting flame-retardant material 101 in the non-foamed state can fully dissipate the heat energy to achieve the heat dissipation and cooling effect of the battery core 201; and when the battery core 201 is abnormally heated, the reactant starts the foaming reaction when the ambient temperature is greater than 130°C, and the reaction is completed within a short foaming time of 30 seconds to 5 minutes. After foaming, the heat-conducting flame-retardant material 101 can block the temperature of the battery core 201 from being transmitted outward and prevent extended combustion. In other words, the single abnormal battery core 201 only smolders inside the foamed thermally conductive flame retardant material 101, and the foamed air chamber of the foamed thermally conductive flame retardant material 101 blocks the temperature transfer, so that the single abnormal battery core 201 will not continue to burn to other battery cores or other electronic components.

[0017] The present invention is a heat-conducting flame-retardant material that can provide heat-conducting, explosion-proof and flame-retardant effects, and is particularly suitable for coating battery cores. The composition and foaming technology of the present invention are different from the existing technology, and its novelty, progress and practical benefits are undoubted. Therefore, it can effectively improve the existing deficiencies and has considerable practicality in use.

[0018] In summary, the specific composition disclosed in the embodiment of the present invention, the silicon dioxide material in the thermally conductive flame-retardant material before foaming acts as a heat conductor, and can prevent the battery core from overheating and exploding before the foaming reaction, can block the temperature transfer of the battery core and prevent extended combustion. In terms of its overall composition and foaming mechanism, it has both thermal conductivity and flame retardant effects, which have never been seen in similar products and have not been disclosed before the application, and it has met the statutory requirements of the Patent Law.

[0019] However, the above is only a preferred embodiment of the present invention, and should not be used to limit the scope of the present invention. That is, all equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the patent of the present invention.

Claims

1. A thermally conductive flame retardant material, characterized in that: The thermally conductive flame retardant material is in a liquid state, a colloidal state or a semi-solid state, and includes: Silicon dioxide, which accounts for 10-85%wt of the whole; A reactant having cross-linking and foaming reactivity, the reactant being mixed with the silicon dioxide; and A catalyst, which is a temperature-sensitized or light-sensitized catalyst, and which is mixed with a reactant to trigger a foaming reaction of the reactant; The heat-conductive flame-retardant material has heat conductivity before the reactant undergoes a foaming reaction, and has flame retardancy after the reactant undergoes a foaming reaction.

2. The thermally conductive flame retardant material according to claim 1, characterized in that: The average particle size d of the silicon dioxide is 5 nm to 10 μm.

3. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant starts the foaming reaction at an ambient temperature greater than 130°C.

4. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant starts the foaming reaction when the ambient temperature is greater than 160°C, and the foaming reaction is completed in 30 seconds to 5 minutes.

5. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant of the thermally conductive flame retardant material has 80%wt of silicon dioxide before the foaming reaction, and the foaming time is 6 seconds to complete the reaction.

6. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant of the thermally conductive flame retardant material has a silicon dioxide content of 40%wt before the foaming reaction, and the foaming time is 4 seconds to complete the reaction.

7. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant of the heat-conducting flame-retardant material is applied to the battery core coating and the inner and outer coating materials of the battery core shell before the foaming reaction.

8. The thermally conductive flame retardant material according to claim 1, characterized in that: The reactant of the heat-conducting flame-retardant material is applied to the battery core coating and the inner and outer coating materials of the battery core shell before the foaming reaction; when the temperature reaches the reaction temperature of the reactant, the foaming reaction is started, and the reactant of the heat-conducting flame-retardant material blocks the temperature transfer inside and outside the battery core after the foaming reaction.

9. The thermally conductive flame retardant material according to claim 1, characterized in that: The flame retardancy of the thermally conductive flame retardant material after the reactant foaming reaction is greater than UL94 rating and reaches V0-5VA.

10. The thermally conductive flame retardant material according to claim 1, characterized in that: The overall thickness of the thermally conductive flame retardant material after the reactant foaming reaction is 600 μm, and the thermal insulation temperature thereof is greater than 800° C.

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