High-thermal-conductivity and high-oil-resistance cable material for electric vehicle charging liquid-cooled cable, preparation method of cable material and cable

Abstract

The invention relates to a cable material for an electric automobile, in particular to a high-heat-conductivity and high-oil-resistance cable material for a charging liquid-cooled cable of the electric automobile, a preparation method of the cable material and the cable. The cable material is prepared from the following components in parts by mass: 55 to 70 parts of ethylene propylene diene monomer, 10 to 20 parts of ethylene-octene copolymer resin, 8 to 12 parts of compatilizer, 6 to 12 parts of polyethylene-acrylate rubber, 5 to 10 parts of ethylene-vinyl acetate copolymer, 2 to 5 parts of polyphthalamide, 60 to 80 parts of flame retardant, 20 to 30 parts of flame-retardant synergist, 15 to 25 parts of heat-conducting filler, 0.5 to 1 part of polyethylene wax and 1.2 to 2 parts of antioxidant. 0.9 to 1.2 parts of a cross-linking agent and 0.1 to 0.3 part of an anti-degradation agent. The high-thermal-conductivity and high-oil-resistance cable material for the charging liquid-cooled cable of the electric vehicle can meet the requirements of flexibility, high flame retardance, low thermal resistance, high and low temperature resistance, aging resistance, cracking resistance and high insulation at the same time.

Description

Technical Field

[0001] The present invention relates to a cable material for electric vehicles, in particular to a high-thermal-conductivity and high-oil-resistance cable material for liquid-cooled charging cables of electric vehicles, a preparation method thereof, and a cable. Background Art

[0002] In recent years, the development of electric vehicles has become a global trend, and my country's electric vehicle industry has also entered a period of rapid development. As a key component of electric vehicles, charging pile cables place high demands on flexibility, mechanical properties, and electrical properties. For charging pile cable materials, high flame retardancy, high insulation, and high flexibility are clearly contradictory. Furthermore, because charging pile cables are exposed to high voltage and high current for extended periods of time, the conductors generate significant heat, raising the overall cable temperature, limiting the current-carrying capacity and impacting charging efficiency. Furthermore, conventional cable materials used for charging pile cables have very low thermal conductivity, preventing heat dissipation in a timely manner, which is extremely detrimental to the cable's service life.

[0003] Chinese patent application CN2014103907595 discloses a modified TPE mixed material for electric vehicle charging pile cables and a preparation method thereof. The TPE mixed material includes the following components by weight: 50-70 parts of thermoplastic elastomer, 10-20 parts of reinforcing agent, 25-55 parts of flame retardant, 0.2-0.5 parts of lubricant, 0.1-0.3 parts of coupling agent, and 0.1-0.3 parts of antioxidant. Due to the large amount of flame retardant added, the material has low strength, poor tear resistance, poor thermal conductivity, heat resistance, aging resistance, and scratch resistance, which limits its application in electric vehicle charging pile cables. Summary of the Invention

[0004] To solve the above problems, the present invention provides a high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable. The specific technical solution is as follows:

[0005] A high-thermal-conductivity and high-oil-resistant cable material for liquid-cooled charging cables for electric vehicles comprises, in parts by mass: 55-70 parts of EPDM rubber, 10-20 parts of ethylene-octene copolymer resin, 8-12 parts of a compatibilizer, 6-12 parts of polyethylene-acrylate rubber, 5-10 parts of ethylene-vinyl acetate copolymer, 2-5 parts of polyphthalamide, 60-80 parts of a flame retardant, 20-30 parts of a flame retardant synergist, 15-25 parts of a thermally conductive filler, 0.5-1 part of polyethylene wax, 1.2-2 parts of an antioxidant, 0.9-1.2 parts of a cross-linking agent, and 0.1-0.3 parts of an anti-degradant.

[0006] Preferably, the ethylene content in the EPDM rubber is 55-70 wt%, and the 5-ethylidene-2-norbornene content is 5-8 wt%.

[0007] Preferably, the ethylene-vinyl acetate has a melt index of 1-3 g / 10 min at 190° C., and a vinyl acetate content by weight of 40-50%;

[0008] The ethylene octene copolymer resin has a melt index of 1.0-1.5 g / 10 min at 190° C.

[0009] Preferably, the compatibilizer is a maleic anhydride monomer grafted onto an ethylene octene copolymer resin.

[0010] Preferably, the methyl acrylate content in the polyethylene-acrylate rubber is 35-40 wt%;

[0011] The content of phthalic acid in the polyphthalamide is 55-65 wt%.

[0012] Preferably, the flame retardant is a mixture of aluminum diethylphosphinate and magnesium hydroxide in a weight ratio of 1:3; the flame retardant synergist is silane coupling agent-coated melamine polyphosphate;

[0013] The antioxidant is a composition in which pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and dilauryl thiodipropionate are mixed in a weight ratio of 2:3; the crosslinking agent is triallyl cyanurate; and the anti-degradation agent is a composition in which 2-(2'-hydroxy-3',5'-dit-pentylphenyl)benzotriazole and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate are mixed in a weight ratio of 2:1.

[0014] Preferably, the thermal conductive filler is prepared by the following method: silicon nitride and aluminum nitride are uniformly mixed in a weight ratio of 3:1, added to an anhydrous ethanol solution of a silane coupling agent with a mass fraction of 2%, ultrasonically dispersed at 60-70°C for 2h, filtered to remove the filtrate and then dried.

[0015] Furthermore, the particle size of the silicon nitride is 1-2 μm, and the particle size of the aluminum nitride is 30-60 nm; and the silane coupling agent is γ-aminopropyltriethoxysilane or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0016] A method for preparing a high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cables, comprising the following steps:

[0017] Step (1), preparing a thermally conductive filler: mixing silicon nitride and aluminum nitride in a weight ratio of 3:1, adding the mixture to an anhydrous ethanol solution of a silane coupling agent having a mass fraction of 2%, ultrasonically dispersing the mixture at 60-70° C. for 2 h, filtering the filtrate, and drying the mixture;

[0018] Step (2), preparing cable material: adding the thermal conductive filler obtained in step (1) and EPDM rubber, ethylene octene copolymer resin, maleic anhydride grafted modified resin, polyethylene-acrylate rubber, ethylene-vinyl acetate copolymer, polyphthalamide, flame retardant, flame retardant synergist, polyethylene wax, antioxidant, crosslinking agent, and anti-degradant to a heated internal mixer and mixing at 170-175° C. for 15-20 minutes to form a mass material;

[0019] Step (3), granulation: the agglomerated material obtained in step (2) is put into a seven-temperature-section twin-screw extruder and extruded into granules to obtain a high-temperature-resistant irradiation-cross-linked low-smoke halogen-free flame-retardant cable material for charging pile cables; the seven temperature sections of the seven-temperature-section twin-screw extruder are 100°C, 145°C, 155°C, 165°C, 165°C, 160°C, and 160°C, respectively.

[0020] A high thermal conductivity and high oil resistance cable for liquid cooling cables used in charging electric vehicles is made of the high thermal conductivity and high oil resistance cable material used in liquid cooling cables used in charging electric vehicles.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable, which can simultaneously meet the requirements of softness, high flame retardancy, low thermal resistance, high and low temperature resistance, aging resistance, cracking resistance, and high insulation.

[0023] The main component is EPDM rubber, which ensures the cable material's softness, high and low temperature resistance, ozone resistance and aging resistance; the addition of polyphthalamide and polyethylene-acrylate rubber improves the heat resistance, weather resistance and other aging resistance and oil resistance of the invention.

[0024] The vinyl acetate in ethylene-vinyl acetate copolymer has good tolerance to fillers and good processing performance, which can improve the processing performance of the matrix. In addition, a compatibilizer is added to improve the interface between the inorganic material and the matrix, thereby improving the mechanical properties of the cable material.

[0025] To improve the thermal conductivity of cable materials, thermally conductive fillers are added to the matrix. Silicon nitride and aluminum nitride, with different particle sizes, are distributed in the matrix at a weight ratio of 3:1. This creates a dense accumulation, increasing the probability of contact between the two particles and achieving higher filling efficiency. This creates a thermally conductive network within the matrix, significantly improving the thermal conductivity of the material. A silane coupling agent is also used to modify the filler, improving the interfacial tension between the filler and the matrix, reducing interfacial thermal resistance, and increasing the dispersion of the filler within the matrix, effectively improving the thermal conductivity and processing performance of the cable material.

[0026] The use of silane coupling agent-coated melamine polyphosphate as a flame retardant synergist allows the cable material to achieve excellent flame retardancy with a relatively small amount of halogen-free flame retardant. This ensures that the cable material meets halogen-free flame retardancy requirements while significantly improving the material's flexibility. The flame retardancy has passed the GB / T2408 V-0 vertical burning test and is environmentally friendly. DETAILED DESCRIPTION

[0027] The present invention will be further described with reference to the embodiments.

[0028] Example 1

[0029] A high-thermal-conductivity and high-oil-resistant cable material for liquid-cooled charging cables for electric vehicles comprises, by weight, 55 parts of EPDM rubber, 20 parts of ethylene-octene copolymer resin, 8 parts of a compatibilizer, 12 parts of polyethylene-acrylate rubber, 5 parts of ethylene-vinyl acetate copolymer, 3 parts of polyphthalamide, 60 parts of a flame retardant, 20 parts of a flame retardant synergist, 15 parts of a thermally conductive filler, 0.6 parts of polyethylene wax, 1.2 parts of an antioxidant, 0.9 parts of a cross-linking agent, and 0.2 parts of an anti-degradant.

[0030] The preparation method of the above-mentioned cable material comprises the following steps:

[0031] Step 1: Prepare thermal conductive filler: mix silicon nitride and aluminum nitride in a weight ratio of 3:1, add to an anhydrous ethanol solution of 2% by mass of a silane coupling agent, ultrasonically disperse at 60-70° C. for 2 h, filter and remove the filtrate, and then dry.

[0032] Step 2, preparing cable material: adding the thermal conductive filler obtained in step 1 and EPDM rubber, ethylene octene copolymer resin, maleic anhydride grafted modified resin, polyethylene-acrylate rubber, ethylene-vinyl acetate copolymer, polyphthalamide, flame retardant, flame retardant synergist, polyethylene wax, antioxidant, crosslinking agent, and anti-degradant to a heated internal mixer and mixing at 170-175° C. for 15-20 minutes to form a mass material;

[0033] Step 3, granulation: the agglomerated material is put into a 7-temperature-section twin-screw extruder and extruded into granules to obtain high-temperature resistant irradiation cross-linked low-smoke halogen-free flame-retardant cable material for charging pile cables; the seven temperature sections of the 7-temperature-section twin-screw extruder are 100°C, 145°C, 155°C, 165°C, 165°C, 160°C, and 160°C, respectively.

[0034] Example 2

[0035] A high-thermal-conductivity and high-oil-resistant cable material for liquid-cooled charging cables of electric vehicles comprises, by weight, 60 parts of EPDM rubber, 10 parts of ethylene-octene copolymer resin, 10 parts of a compatibilizer, 12 parts of polyethylene-acrylate rubber, 8 parts of ethylene-vinyl acetate copolymer, 2 parts of polyphthalamide, 70 parts of a flame retardant, 25 parts of a flame retardant synergist, 20 parts of a thermally conductive filler, 0.8 parts of polyethylene wax, 1.6 parts of an antioxidant, 1.2 parts of a cross-linking agent, and 0.3 parts of an anti-degradant.

[0036] The preparation method is the same as that of Example 1.

[0037] Example 3

[0038] A high-thermal-conductivity and high-oil-resistant cable material for liquid-cooled charging cables of electric vehicles comprises, by weight, 70 parts of EPDM rubber, 10 parts of ethylene-octene copolymer resin, 8 parts of a compatibilizer, 6 parts of polyethylene-acrylate rubber, 6 parts of ethylene-vinyl acetate copolymer, 5 parts of polyphthalamide, 80 parts of a flame retardant, 30 parts of a flame retardant synergist, 25 parts of a thermally conductive filler, 1 part of polyethylene wax, 2 parts of an antioxidant, 1.2 parts of a cross-linking agent, and 0.1 part of an anti-degradant.

[0039] The preparation method is the same as that of Example 1.

[0040] Comparative Example 1:

[0041] The cable material includes: 55 parts of EPDM rubber, 20 parts of ethylene octene copolymer resin, 8 parts of compatibilizer, 12 parts of polyethylene-acrylate rubber, 5 parts of ethylene-vinyl acetate copolymer, 3 parts of polyphthalamide, 60 parts of flame retardant, 20 parts of flame retardant synergist, 0.6 parts of polyethylene wax, 1.2 parts of antioxidant, 0.9 parts of cross-linking agent, and 0.2 parts of anti-degradant.

[0042] The preparation method is the same as that of Example 1.

[0043] Comparative Example 2:

[0044] The cable material includes: 55 parts of EPDM rubber, 20 parts of ethylene octene copolymer resin, 8 parts of compatibilizer, 12 parts of polyethylene-acrylate rubber, 5 parts of ethylene-vinyl acetate copolymer, 3 parts of polyphthalamide, 60 parts of flame retardant, 20 parts of thermal conductive filler, 0.6 parts of polyethylene wax, 1.2 parts of antioxidant, 0.9 parts of cross-linking agent, and 0.2 parts of anti-degradant.

[0045] The preparation method is the same as that of Example 1.

[0046] Comparative Example 3:

[0047] The cable materials include: 55 parts of EPDM rubber, 20 parts of ethylene octene copolymer resin, 12 parts of polyethylene-acrylate rubber, 5 parts of ethylene-vinyl acetate copolymer, 3 parts of polyphthalamide, 60 parts of flame retardant, 20 parts of flame retardant synergist, 15 parts of thermal conductive filler, 0.6 parts of polyethylene wax, 1.2 parts of antioxidant, 0.9 parts of cross-linking agent, and 0.2 parts of anti-degradant.

[0048] The preparation method is the same as that of Example 1.

[0049] Performance testing of the high-thermal-conductivity, high-oil-resistant cable materials for electric vehicle charging liquid-cooling cables prepared in Examples 1-3 was conducted. The performance indicators are shown in Table 1. The data presented in the Examples and Comparative Examples are typical values. It can be seen that the use of thermally conductive fillers significantly improves the thermal conductivity of the products, the flame retardant synergist significantly enhances the flame retardancy of the products, and the compatibilizer improves the mechanical properties of the products.

[0050] Performance comparison table:

[0051]

[0052] A high-thermal-conductivity, high-oil-resistance cable for liquid-cooled charging cables of electric vehicles is made of a high-thermal-conductivity, high-oil-resistance cable material for liquid-cooled charging cables of electric vehicles. A preparation method is used to prepare a high-thermal-conductivity, high-oil-resistance cable material for liquid-cooled charging cables of electric vehicles.

Claims

1. A high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable, characterized in that: In terms of mass, it includes: 55-70 parts of EPDM rubber, 10-20 parts of ethylene octene copolymer resin, 8-12 parts of compatibilizer, 6-12 parts of polyethylene acrylate rubber, 5-10 parts of ethylene vinyl acetate copolymer, 2-5 parts of polyphthalamide, 60-80 parts of flame retardant, 20-30 parts of flame retardant synergist, 15-25 parts of thermal conductive filler, 0.5-1 part of polyethylene wax, 1.2-2 parts of antioxidant, 0.9-1.2 parts of crosslinking agent, and 0.1-0.3 parts of anti-degradant.

2. The high thermal conductivity and oil resistant cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The ethylene content in the EPDM rubber is 55-70 wt %, and the content of 5-ethylidene-2-norbornene is 5-8 wt %.

3. The high thermal conductivity and oil resistant cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The ethylene vinyl acetate copolymer has a melt index of 1-3 g / 10 min at 190° C., and a weight content of vinyl acetate of 40-50%. The ethylene octene copolymer resin has a melt index of 1.0-1.5 g / 10 min at 190° C.

4. The high thermal conductivity and oil resistant cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The compatibilizer is a maleic anhydride monomer grafted product of ethylene octene copolymer resin.

5. The high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The content of methyl acrylate in the polyethylene-acrylate rubber is 35-40 wt %; the content of phthalic acid in the polyphthalamide is 55-65 wt %.

6. The high thermal conductivity and oil resistance cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The flame retardant is a mixture of aluminum diethylphosphinate and magnesium hydroxide in a weight ratio of 1:3; the flame retardant synergist is silane coupling agent coated melamine polyphosphate; The antioxidant is a composition in which pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and dilauryl thiodipropionate are mixed in a weight ratio of 2:3; the crosslinking agent is triallyl cyanurate; and the anti-degradation agent is a composition in which 2-(2'-hydroxy-3',5'-dit-pentylphenyl)benzotriazole and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate are mixed in a weight ratio of 2:

1.

7. The high thermal conductivity and oil resistance cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The thermal conductive filler is prepared by the following method: silicon nitride and aluminum nitride are uniformly mixed in a weight ratio of 3:1, added into an anhydrous ethanol solution of a silane coupling agent with a mass fraction of 2%, ultrasonically dispersed at 60-70°C for 2h, filtered to remove the filtrate, and then dried.

8. The high thermal conductivity and oil resistance cable material for electric vehicle charging liquid cooling cable according to claim 7, characterized in that: The particle size of the silicon nitride is 1-2 μm, and the particle size of the aluminum nitride is 30-60 nm; the silane coupling agent is γ-aminopropyltriethoxysilane or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

9. A method for preparing a high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable, used for the high thermal conductivity and high oil resistance cable material for electric vehicle charging liquid cooling cable according to claim 1, characterized in that: The following steps are involved: Step (1), preparing a thermally conductive filler: mixing silicon nitride and aluminum nitride in a weight ratio of 3:1, adding the mixture to an anhydrous ethanol solution of a silane coupling agent having a mass fraction of 2%, ultrasonically dispersing the mixture at 60-70° C. for 2 h, filtering the filtrate, and drying the mixture; Step (2), preparing cable material: adding the thermal conductive filler obtained in step (1) and EPDM rubber, ethylene octene copolymer resin, maleic anhydride grafted modified resin, polyethylene-acrylate rubber, ethylene-vinyl acetate copolymer, polyphthalamide, flame retardant, flame retardant synergist, polyethylene wax, antioxidant, crosslinking agent, and anti-degradant to a heated internal mixer and mixing at 170-175° C. for 15-20 minutes to form a mass material; Step (3), granulation: the agglomerated material obtained in step (2) is put into a seven-temperature-section twin-screw extruder and extruded into granules to obtain a high-temperature-resistant irradiation-cross-linked low-smoke halogen-free flame-retardant cable material for charging pile cables; the seven temperature sections of the seven-temperature-section twin-screw extruder are 100°C, 145°C, 155°C, 165°C, 165°C, 160°C, and 160°C, respectively.

10. A high thermal conductivity and high oil resistance cable for electric vehicle charging liquid cooling cable, characterized in that: The electric vehicle charging liquid cooling cable according to claim 1 is made of a high thermal conductivity and high oil resistance cable material.

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