A low conductance HES nanofluid coolant

Abstract

The application provides a chemical combination formula of a low-conductance HES nanofluid coolant, which comprises nanometer magnesium oxide, hydroxyethyl starch HES, deionized water (non-conductive), urotropin (hexamethylenetetramine), TBHQ (2-tert-butyl hydroquinone), and SMS (dimethyl sulfoxide). The preparation method comprises S1: surface modification of magnesium oxide, S2: preparation of HES colloidal solution, and S3: preparation of nanometer coolant. The coolant has the characteristics of low conductivity, can effectively prevent battery short circuit and explosion caused by leakage of a heat exchanger, and is suitable for a circulating cooling system of an electric vehicle and other electrical appliances.

Description

Technical Field

[0001] This invention relates to a low-conductivity HES nanofluid coolant, belonging to the field of nanofluid and chemical combination technology, aiming to solve the safety hazards and performance defects of coolants in existing cooling systems, and to provide a safe and efficient cooling solution. Background Technology

[0002] Most current electric vehicle liquid cooling systems use aqueous solutions of polyols as coolants. However, these coolants are conductive, and if a heat exchanger leaks, it could potentially cause a battery short circuit or even spontaneous combustion, posing a significant safety risk.

[0003] In addition, while anhydrous ethylene glycol coolants for engines, such as American Evans coolant, have certain characteristics, they are flammable and have a heat dissipation capacity of only 40% that of water. They are not ideal liquid cooling materials because they are insufficient in terms of safety and heat dissipation performance.

[0004] Currently, there are several patents related to electric vehicle coolants, such as "A High-Efficiency Thermally Conductive Coolant for New Energy Vehicles and Its Preparation Method and Process," composed of alumina, silane coupling agent, ethylene glycol, propylene glycol, and tap water; and patents related to battery charging and discharging, such as "A High-Power Charging Pile Charging Cable Insulation Liquid Cooling System and Method," and CN107734925a, CN 109215872a, and CN 201910239407.2. However, the coolants involved in these patents still need improvement in terms of safety, conductivity, and heat dissipation performance.

[0005] Hydroxyethyl starch (HES), a reaction product of ethylene oxide and starch, can form a stable colloid with water and is biodegradable. In the medical field, it is often used as a plasma substitute, and it also has wide applications in the food, light industry, and oil drilling sectors.

[0006] Magnesium oxide is a high-performance insulating and thermally conductive material with a thermal conductivity 60 times greater than that of water. It is often used as a heat transfer filler between the resistance wire and the metal tube in electric heating tubes, providing the possibility of improving the thermal conductivity of the coolant. Summary of the Invention

[0007] The low-conductivity HES nanofluid coolant provided by this invention has the following significant innovations: The unique chemical combination includes nano-magnesium oxide, HES, deionized water (non-conductive), hexamethylenetetramine, TBHQ, and SMS. This combination effectively prevents battery short circuits and explosions caused by coolant leakage, making it an original and revolutionary technology in the field of coolants.

[0008] The low-conductivity heat exchange colloid formed using HES, nano-magnesium oxide, and deionized water as the base liquid not only has excellent thermal conductivity but also effectively prevents particle aggregation, making it innovative and unique in terms of technology and product characteristics.

[0009] The purpose of this invention is to develop a low-conductivity HES nanofluid coolant, which can effectively prevent battery combustion and explosion, and the related technology is ready for industrialization and can be widely used in actual production and the market.

[0010] Preparation method: The preparation and implementation steps include: S1: Magnesium oxide surface modification; S2: Preparation of HES colloidal solution; S3: Preparation of nano-cooling liquid.

[0011] Step S1 is as follows: 0.1-0.5% by mass of magnesium oxide nanopowder (particle size 10-50nm), 0.5-1.0% of hexamethylenetetramine, and 0.1-0.3% of 2-tert-butylhydroquinone are sequentially added to purified water in a container and mixed. The mixture is stirred at 60-80 r / min for 20 min at room temperature to obtain a modified micropowder mixture. The mixture is then stopped and set aside for later use.

[0012] Step S2 is as follows: Hydroxyethyl starch is added to the above modified micro powder mixture at a mass percentage concentration of 0.8-1.5%, and stirred at a high speed of 3000 r / min at a constant temperature of 60℃ for 60 min to disperse and dissolve. After removal, it is transferred to an ultrasonic oscillator and dispersed by oscillation at a power of 150 W and a frequency of 20-40 kHz for 20-30 min to obtain nanofluid for later use.

[0013] Step S3 is as follows: Dimethyl sulfoxide is mixed with the nanofluid obtained in step S2 at a mass percentage concentration of 5-7% in a reactor, and stirred at a constant temperature of 60℃ and a speed of 60-80 r / min for 15 min to dissolve it. The nanocooling liquid product is then obtained.

[0014] S1: Magnesium oxide surface modification; 1g of magnesium oxide nanopowder (particle size 10-50nm), 5g of hexamethylenetetramine, and 1g of 2-tert-butylhydroquinone were sequentially placed into a reactor containing 993g of deionized water. The mixture was stirred at 60-80r / min at room temperature for 20min, and then the reactor was stopped.

[0015] S2: Preparation of HES colloidal solution; Add 8g of hydroxyethyl starch to the reactor containing the modified micro powder mixture, and disperse and dissolve it at a high speed of 3000 r / min under constant temperature of 60℃ for 60 min. After removal, transfer it to an ultrasonic oscillator and disperse it at 150 W power and 20-40 kHz frequency for 20-30 min. Stop the machine after the reaction is completed.

[0016] S3: Preparation of nano-cooling liquid; 50g of dimethyl sulfoxide was placed into the HES colloidal reactor obtained from the above reaction, and stirred and dissolved at a speed of 60-80 r / min and a constant temperature of 60℃ for 15 min to obtain a nano-cooling liquid product with a boiling point of 120℃ and a freezing point of -25℃.

[0017] To verify the product's stability, it was placed in a 100℃ oil bath and observed for 7 days under constant temperature conditions. After 7 days of observation, no particle aggregation, stratification, or sedimentation was observed, which fully demonstrates that the product has good long-term stability and can meet the stability requirements in practical applications. The low-conductivity HES nanofluid coolant of the present invention exhibits excellent performance in terms of safety, stability and thermal conductivity, and has broad application prospects.

Claims

1. A low-conductivity nano-cooling liquid based on hydroxyethyl starch, magnesium oxide, and deionized water, the preparation process of which includes the following steps: S1: Magnesium oxide surface modification; S2: Preparation of HES colloidal solution; S3: Preparation of nano-cooling fluid.

2. The preparation technique according to claim 1, characterized in that: Step S1 is as follows: 0.1-0.5% by mass of magnesium oxide nanopowder (MgO, particle size ≤50nm), 0.5-1.0% by mass of hexamethylenetetramine (adsorption-type corrosion inhibitor), and 0.1-0.3% by mass of 2-tert-butylhydroquinone (TBHQ) (oxygen scavenger) are mixed with deionized water and placed in a reactor. The mixture is stirred at 60-80 r / min at room temperature for 20 min, then the reactor is stopped and the mixture is ready for use.

3. The technology according to claim 1, characterized in that: Step S2 is as follows: Hydroxyethyl starch is added to the reactor described in claim 2 at a mass percentage concentration of 0.8-1.5%, mixed with the pretreatment solution, and dissolved and dispersed at a constant temperature of 60°C and a rotation speed of 3000 r / min. After stirring for 60 min, it is taken out and transferred to an ultrasonic oscillator. At room temperature, it is oscillated and dispersed at a power of 150 W and a frequency of 20-40 kHz for 20-30 min, and then taken out for later use.

4. The technology according to claim 1, characterized in that: Step S3 is as follows: Dimethyl sulfoxide (SMS) is mixed with the nanofluid prepared in claim 3 in a reactor at a mass percentage concentration of 5-7%, and the mixture is kept at a constant temperature of 60°C and stirred at 60-80 r / min for 15 min to dissolve, thereby obtaining the product.

5. According to claim 3, the molecular weight of the hydroxyethyl starch (HES) is ≤2 million Daltons.

6. According to the technology described in claims 1-5, the resulting low electrical conductivity and high thermal conductivity nano-coolant is used in electric vehicles, charging pile cables, and circulating heat exchange systems for batteries and electrical equipment.