Mineral oil type charging pile insulating cooling liquid and preparation method thereof

Abstract

The invention relates to the technical field of charging pile liquid cooling, in particular to mineral oil type charging pile insulating cooling liquid and a preparation method thereof.The mineral oil type charging pile insulating cooling liquid is prepared from, by mass, 99.0-99.8 parts of mineral type base oil and 0.2-1.0 part of antioxidant, and the mineral type base oil is prepared from mineral oil through a hydrotreating process and then through a heat treatment process; and carrying out a pour point depressing and refining process. According to the mineral oil type charging pile insulation cooling liquid, the mineral oil treated through the hydrogenation pour point depressing process is adopted as the base oil, the low-temperature property is good, the pour point is lower than-60 DEG C, the low-temperature kinematic viscosity is smaller than 2000 mm < 2 > / s, meanwhile, the withstand voltage is larger than 50 KV, and the mineral oil type charging pile insulation cooling liquid can be in direct contact with a cable connected with a charging pile and has good insulativity and low-temperature pumpability; the insulation requirement of high-power charging pile work can be met, and stable operation of the charging pile in winter is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid cooling for charging piles, and is a mineral oil-based insulating coolant for charging piles and a preparation method thereof. Background Art

[0002] In recent years, with the continuous reduction of fossil energy resources and the prominent environmental problems, new energy electric vehicles, as a green means of transportation, have developed rapidly. To improve the electrification level of vehicles in the public domain and accelerate the construction of a green and low-carbon transportation system, relevant departments have clearly put forward to accelerate the full electrification of vehicles in the public domain. It is required to build a moderately advanced charging and swapping infrastructure, promote the application of new technologies and new models, and accelerate the application of intelligent and orderly charging, high-power charging, and automatic charging technologies.

[0003] High-power charging technology is the trend of the development of new energy electric vehicle charging. The rapid development of fast charging and ultra-fast charging has solved the problem of "charging anxiety". With the super-fast charging technology, the energy density of the equipment is high and the temperature rises quickly. The traditional air-cooling method can no longer meet the heat dissipation requirements, and the liquid-cooling method is an effective solution. The liquid-cooling methods include cold plate liquid cooling and immersion liquid cooling, and the immersion liquid cooling is more efficient than the cold plate liquid cooling. Cold plate liquid cooling: Common coolants include water, ethylene glycol aqueous solution, silicone oil, fluorinated liquid, etc. Immersion liquid cooling: Higher insulation of the coolant is required. The working process of high-power charging piles has the following characteristics: 1. High working voltage and large current, the working voltage of the charging pile reaches 1000V and the working current reaches 600A; 2. The charging pile works in the outdoor environment with large temperature differences in four seasons. Higher performance requirements are also imposed on the coolant of the charging pile: 1. Good insulation of the coolant is required; 2. Good low-temperature pumping performance of the coolant is required.

[0004] At present, regarding the current situation of charging pile coolants in China, the coolants mainly include aqueous solutions of oil, water, propylene glycol or ethylene glycol, etc. Aqueous solutions of water, propylene glycol or ethylene glycol are non-insulators, and no insulation requirements are imposed on oil either. Therefore, the cooling method adopts cold plate indirect cooling. Since the working voltage of high-power charging piles is as high as 1000V, once leakage occurs, it will cause fatal damage to the equipment. For example, the Chinese patent document with the publication number CN217902783U discloses a liquid-cooled charging pile cable, and the coolant used in its liquid-cooled charging pile cable is water cooling. The Chinese patent document with the publication number CN216659606U discloses a liquid-cooled charging pile. In its cooling circulation loop, the first coolant adopts oil, water, air, propylene glycol or ethylene glycol, etc., and the first driving source adopts a pump body. The Chinese patent document with the publication number CN216817914U discloses a new type of liquid-cooled charging pile cable, and the cooling method it adopts is cold plate liquid cooling. The Chinese patent documents with the publication numbers CN114596991A and CN113539550A adopt the same cold plate liquid cooling method. The existing charging pile coolants all adopt non-insulating coolants, and the cooling method mostly adopts cold plate liquid cooling. Cold plate liquid cooling transfers heat through heat conduction, which has the disadvantages of slow cooling response, low cooling efficiency and high working energy consumption. Summary of the Invention

[0005] The present invention provides a mineral oil type insulating coolant for charging piles, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems of slow cooling response, low cooling efficiency and high working energy consumption of the existing charging pile coolants.

[0006] One of the technical solutions of the present invention is achieved by the following measures: A mineral oil type insulating coolant for charging piles, per one hundred parts by mass of the raw materials includes: 99.0 parts to 99.8 parts of mineral type base oil, and 0.2 parts to 1.0 part of antioxidant. The mineral type base oil is prepared by first subjecting petroleum fractions to a hydrotreating process and then a dewaxing and refining process.

[0007] The following is a further optimization or / and improvement of the above-mentioned invention technical solution: The above-mentioned mineral oil type insulating coolant for charging piles is prepared by the following method: Mix the required amount of mineral type base oil and antioxidant, heat to 50°C to 60°C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type insulating coolant for charging piles.

[0008] The hydrotreating process conditions of the above-mentioned mineral type base oil are: reaction temperature 240°C to 410°C, reaction pressure 15.0MPa to 17.0MPa, volume space velocity 0.4h -1 to 1.7h -1 and the hydrogen-oil ratio (V / V) is 500 to 1000.

[0009] The dewaxing and refining process conditions of the above mineral base oil are as follows: the reaction temperature is 220°C to 400°C, the reaction pressure is 15.0 MPa to 17.0 MPa, the volumetric space velocity is 0.5 h -1 to 1.5 h -1 , and the hydrogen-oil ratio (V / V) is 500 to 1000.

[0010] The above mineral base oil is one or more of mineral base oils A, B, and C; among them, the distillation range of mineral base oil A is 250°C to 400°C, the distillation range of mineral base oil B is 280°C to 450°C, and the distillation range of mineral base oil C is 320°C to 480°C.

[0011] The above antioxidant is one or both of 2,6-di-tert-butyl-p-cresol and alkyl diphenylamine.

[0012] The breakdown voltage of the above mineral oil type charging pile insulating coolant is greater than 50 kV.

[0013] The saturated water absorption of the above mineral oil type charging pile insulating coolant is less than 20 mg / kg.

[0014] The kinematic viscosity at 40°C of the above mineral oil type charging pile insulating coolant is 5 mm 2 / s to 10 mm 2 / s.

[0015] The second technical solution of the present invention is achieved by the following measures: a preparation method of a mineral oil type charging pile insulating coolant, which is prepared according to the following steps: mix the required amount of mineral base oil and antioxidant, heat to 50°C to 60°C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type charging pile insulating coolant.

[0016] The present invention provides a mineral oil type charging pile insulating coolant, which has good insulation performance and excellent low-temperature performance, can meet the insulation requirements of high-power charging piles, and at the same time, ensure the stable operation of charging piles in winter. The mineral oil type charging pile insulating coolant of the present invention can be applied in immersion liquid cooling, a cooling method that can be in direct contact with the heating unit, and has the characteristics of fast cooling response, high heat transfer efficiency, and good temperature uniformity. Specific Embodiments

[0017] The present invention is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solution of the present invention and the actual situation. All chemical reagents and chemical supplies mentioned in the present invention are well-known and commonly used chemical reagents and chemical supplies in the prior art without special instructions; the percentages in the present invention are mass percentages without special instructions; normal temperature and room temperature in the present invention generally refer to the temperature of 15°C to 25°C, and are generally defined as 25°C.

[0018] The present invention will be further described in conjunction with the embodiments as follows: Embodiment 1: For the mineral oil type charging pile insulating coolant, per one hundred parts by mass of the raw materials, it includes: 99.0 to 99.8 parts of mineral type base oil, and 0.2 to 1.0 part of antioxidant. The mineral type base oil is prepared by first subjecting petroleum fractions to a hydrotreating process and then a dewaxing and refining process.

[0019] Embodiment 2: As an optimization of the above embodiment, the mineral oil type charging pile insulating coolant is prepared by the following method: Mix the required amount of mineral type base oil and antioxidant, heat to 50°C to 60°C, stir until clear and transparent, then cool to room temperature, and obtain the mineral oil type charging pile insulating coolant after filtration.

[0020] Embodiment 3: As an optimization of the above embodiment, the hydrotreating process conditions of the mineral type base oil are: reaction temperature 240°C to 410°C, reaction pressure 15.0 MPa to 17.0 MPa, volume hourly space velocity 0.4 h -1 to 1.7 h -1 , and the hydrogen-oil ratio (V / V) is 500 to 1000.

[0021] Embodiment 4: As an optimization of the above embodiment, the dewaxing and refining process conditions of the mineral type base oil are: reaction temperature 220°C to 400°C, reaction pressure 15.0 MPa to 17.0 MPa, volume hourly space velocity 0.5 h -1 to 1.5 h -1 , and the hydrogen-oil ratio (V / V) is 500 to 1000.

[0022] Embodiment 5: As an optimization of the above embodiment, the mineral type base oil is one or more of mineral type base oils A, B, and C; wherein, the distillation range of mineral type base oil A is 250°C to 400°C, the distillation range of mineral type base oil B is 280°C to 450°C, and the distillation range of mineral type base oil C is 320°C to 480°C.

[0023] Embodiment 6: As an optimization of the above embodiment, the antioxidant is one or two of 2,6-di-tert-butyl-p-cresol and alkyl diphenylamine.

[0024] Embodiment 7: As an optimization of the above embodiment, the breakdown voltage of the mineral oil type charging pile insulating coolant is greater than 50 kV.

[0025] Embodiment 8: As an optimization of the above embodiment, the saturated water absorption of the mineral oil type charging pile insulating coolant is less than 20 mg / kg.

[0026] Embodiment 9: As an optimization of the above embodiment, the kinematic viscosity of the mineral oil type charging pile insulating coolant at 40°C is 5 mm 2 / s to 10 mm 2 / s.

[0027] Example 10: The mineral oil type charging pile insulating coolant, per 100 parts by mass of raw materials, includes: 99.6 parts of mineral type base oil A and 0.4 part of antioxidant 2,6 - di - tert - butyl - p - cresol. Mix the mineral type base oil A and 2,6 - di - tert - butyl - p - cresol, heat to 55 °C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type charging pile insulating coolant.

[0028] Example 11: The mineral oil type charging pile insulating coolant, per 100 parts by mass of raw materials, includes: 99.0 parts of mineral type base oil B and 1.0 part of antioxidant alkyl diphenylamine. Mix the mineral type base oil B and alkyl diphenylamine, heat to 50 °C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type charging pile insulating coolant.

[0029] Example 12: The mineral oil type charging pile insulating coolant, per 100 parts by mass of raw materials, includes: 19.8 parts of mineral type base oil A, 80.0 parts of mineral type base oil B, 0.1 part of antioxidant 2,6 - di - tert - butyl - p - cresol, and 0.1 part of alkyl diphenylamine. Mix the mineral type base oil A, mineral type base oil B, 2,6 - di - tert - butyl - p - cresol, and alkyl diphenylamine, heat to 60 °C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type charging pile insulating coolant.

[0030] Example 13: The mineral oil type charging pile insulating coolant, per 100 parts by mass of raw materials, includes: 30 parts of mineral type base oil A, 43 parts of mineral type base oil B, 26.8 parts of mineral type base oil C, and 0.2 part of antioxidant 2,6 - di - tert - butyl - p - cresol. Mix the mineral type base oil A, mineral type base oil B, mineral type base oil C, and 2,6 - di - tert - butyl - p - cresol, heat to 55 °C, stir until clear and transparent, then cool to room temperature, and filter to obtain the mineral oil type charging pile insulating coolant.

[0031] Comparative example: For this charging pile coolant, the base oil uses mineral oil that has not been processed by the hydrotreating process and the dewaxing and refining process. Its raw materials include 99.8 parts of mineral oil and 0.2 part of antioxidant 2,6 - di - tert - butyl - p - cresol. Mix the mineral oil and 2,6 - di - tert - butyl - p - cresol, heat to 55 °C, stir until clear and transparent, cool to room temperature, and filter to obtain the charging pile coolant.

[0032] The kinematic viscosity, pour point, thermal conductivity, specific heat, saturated water absorption, and breakdown voltage performance indicators of the mineral oil-based charging pile insulating coolant in Examples 10 to 13 and the charging pile coolant in the comparative example were tested, and the performance comparison is shown in Table 1. It can be seen from Table 1 that the mineral oil-based charging pile insulating coolant in Examples 10 to 13 prepared by the solution of the present invention is superior to the charging pile coolant in the comparative example in terms of kinematic viscosity, pour point, thermal conductivity, specific heat, water content, and breakdown voltage performance indicators. The mineral oil-based charging pile insulating coolant of the present invention is prepared by a hydro-upgrading and dewaxing process for the base oil, and has the characteristics of good insulation and good low-temperature pumping performance. The product meets the insulation requirements in the high-power operation of charging piles and ensures the normal operation of charging piles in winter.

[0033] In summary, for the mineral oil-based charging pile insulating coolant of the present invention, the mineral oil treated by the hydro-upgrading and dewaxing process is used as the base oil, which has good low-temperature performance, a pour point lower than -60°C, and a low-temperature kinematic viscosity (at -40°C) less than 2000 mm 2 / s. At the same time, the withstand voltage is greater than 50 KV, and it can be in direct contact with the cable connected to the charging pile, having good insulation and low-temperature pumping performance, being able to meet the insulation requirements of high-power charging piles, and ensuring the stable operation of charging piles in winter.

[0034] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be added or subtracted according to actual needs to meet the requirements of different situations.

Claims

1. A mineral oil-based insulating coolant for charging piles, characterized in that Per hundred parts by mass, the raw materials include: 99.0 to 99.8 parts of mineral base oil, and 0.2 to 1.0 part of antioxidant. The mineral base oil is prepared by first subjecting petroleum fractions to a hydrotreating process and then a dewaxing and refining process.

2. The mineral oil type charging pile insulating coolant according to claim 1, wherein It is prepared by the following method: Mix the required amount of mineral base oil and antioxidant, heat to 50°C to 60°C, stir until clear and transparent, then cool to room temperature, and obtain the mineral oil type charging pile insulating coolant after filtration.

3. The mineral oil-based insulating coolant for charging piles according to claim 1 or 2, characterized in that The hydrotreating process conditions for mineral-based base oils are as follows: reaction temperature is 240°C to 410°C, reaction pressure is 15.0 MPa to 17.0 MPa, volumetric space velocity is 0.4 h -1 to 1.7 h -1 , and the hydrogen-to-oil ratio is 500 to 1000.

4. The mineral oil-based insulating coolant for charging piles according to any one of claims 1 to 3, characterized in that The dewaxing and refining process conditions for mineral-based base oils are as follows: reaction temperature is 220°C to 400°C, reaction pressure is 15.0 MPa to 17.0 MPa, volumetric space velocity is 0.5 h -1 to 1.5 h -1 , and the hydrogen-oil ratio is 500 to 1000.

5. The mineral oil type charging pile insulating coolant according to any one of claims 1 to 4, characterized in that The mineral base oil is one or more of mineral base oils A, B, and C; among them, the distillation range of mineral base oil A is 250°C to 400°C, the distillation range of mineral base oil B is 280°C to 450°C, and the distillation range of mineral base oil C is 320°C to 480°C.

6. The mineral oil-based insulating coolant for charging piles according to any one of claims 1 to 5, characterized in that The antioxidant is one or both of 2,6-di-tert-butyl-p-cresol and alkyl diphenylamine.

7. The mineral oil-based insulating coolant for charging piles according to any one of claims 1 to 6, characterized in that The breakdown voltage is greater than 50 kV.

8. The mineral oil type charging pile insulating coolant according to any one of claims 1 to 7, characterized in that The saturated water absorption is less than 20 mg / kg.

9. The mineral oil type charging pile insulating coolant according to claims 1 to 8, characterized in that The kinematic viscosity at 40°C is 5 mm 2 / s to 10 mm 2 / s.

10. A method for preparing the mineral oil-based insulating coolant for charging piles according to claim 1 or 3 or 4 or 5 or 6 or 7 or 8 or 9, characterized in that It is carried out according to the following steps: Mix the required amount of mineral base oil and antioxidant, heat to 50°C to 60°C, stir until clear and transparent, then cool to room temperature, and obtain the mineral oil type charging pile insulating coolant after filtration.

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