Cooling liquid additive composition and cooling liquid

Abstract

The invention discloses a cooling liquid additive composition and a cooling liquid, and belongs to the technical field of cooling liquid preparation. The coolant additive composition comprises a corrosion inhibitor ZIF-8 ellagic acid nanoparticles, a heat conduction enhancer graphene oxide chitosan, dispersing agents polyethylene glycol and N-trimethyl chitosan, and an antioxidant vitamin E acetate. The invention further discloses a scheme for preparing cooling liquid by using the cooling liquid additive composition and application of the cooling liquid additive composition in a new energy automobile thermal management system. The problem that the corrosion inhibition efficiency of a traditional cooling liquid is attenuated can be effectively solved by loading natural polyphenol on a metal organic framework MOF and matching with other functional aids.

Description

Technical Field

[0001] This invention belongs to the field of coolant preparation technology, specifically relating to a coolant additive composition and a coolant. Background Technology

[0002] With the explosive growth of the new energy vehicle market, the high energy density, fast charging requirements, and complex operating conditions of power batteries have placed stringent challenges on coolant performance. Power battery thermal management systems need to operate stably across a wide temperature range of -40℃ to 120℃, while also facing requirements for high-voltage electrical safety, multi-metal compatibility (aluminum battery casings, copper piping, etc.), and long lifespan. According to the GB29743.2 standard for "Electric Vehicle Coolants," coolants must pass multi-metal corrosion tests (e.g., immersing copper, brass, and aluminum samples at 80℃ for 1064 hours, with a mass change ≤ ±10mg / sample) and meet insulation requirements with a conductivity ≤ 100μS / cm. However, traditional coolants generally suffer from reduced corrosion inhibition efficiency, directly leading to a reduction in battery cycle life of more than 20%, which has become an urgent problem to be solved in the industry. Summary of the Invention

[0003] To address the common problem of declining corrosion inhibition efficiency in traditional coolants, the coolant additive composition of this invention is designed to eliminate traditional high-conductivity inorganic salt corrosion inhibitors (such as phosphates and silicates) and instead employ nonionic and weakly ionic components. In this coolant additive composition, ZIF-8@ellagic acid possesses dual functions of enhanced thermal conductivity and dynamic corrosion protection. ZIF-8@ellagic acid has a unique MOF crystalline structure, with its phenolic hydroxyl groups anchored in ethylene glycol via hydrogen bonds, improving the dispersion stability of nanoparticles and achieving enhanced thermal conductivity. The polyphenolic structure of ellagic acid in the ZIF-8@ellagic acid nanoparticles releases antioxidant groups in acidic environments, inhibiting metal corrosion and achieving a smart response of "passive thermal conduction + active corrosion protection." Furthermore, graphene oxide and chitosan form a stable colloid through chemical cross-linking, preventing graphene oxide from agglomerating. Simultaneously, the amino groups of chitosan form hydrogen bonds with the hydroxyl groups on the ZIF-8 surface, enhancing multi-component compatibility and constructing a thermally conductive network of "nanoparticle-polymer-solvent."

[0004] Based on the above design concept, the present invention adopts the following technical solution:

[0005] A coolant additive composition includes a corrosion inhibitor, a thermal conductivity enhancer, a dispersant, and an antioxidant. The corrosion inhibitor is ZIF-8@ellagic acid nanoparticles, the thermal conductivity enhancer is graphene oxide chitosan, the dispersant includes polyethylene glycol and N-trimethyl chitosan, and the antioxidant is vitamin E acetate.

[0006] Furthermore, the preparation method of the ZIF-8@ellagic acid nanoparticles includes the following steps:

[0007] (1) Dissolve 200g of 2-methylimidazole in 200mL of methanol, add 10g of zinc nitrate, and stir at 60℃ for 30min to generate ZIF-8 precursor;

[0008] (2) Add 5g ellagic acid and 2mL triethylamine, and sonicate for 2h to anchor ellagic acid in the ZIF-8 channel through coordination bonds;

[0009] (3) The solvent was removed by vacuum distillation to obtain a light yellow powder of ellagic acid supported on a zeolite imidazole ester framework, which is ZIF-8@ellagic acid nanoparticles.

[0010] Furthermore, the above-mentioned coolant additive composition comprises the following components in parts by weight:

[0011] ZIF-8@ellagic acid nanoparticles, 0.6–1.2 parts;

[0012] 0.2–0.5 parts of graphene oxide chitosan;

[0013] 1.5 to 3.0 parts of polyethylene glycol;

[0014] 0.2–0.3 parts of N-trimethyl chitosan;

[0015] Vitamin E acetate 0.1 to 0.2 parts.

[0016] Furthermore, in the above-mentioned coolant additive composition, the ZIF-8@ellagic acid nanoparticles have a particle size of 80-120 nm.

[0017] The present invention also provides a coolant comprising ethylene glycol, deionized water and the coolant additive composition described above; a pH adjuster and an antifoaming agent are also added during the preparation process, wherein the pH adjuster is sodium citrate and the antifoaming agent is polyethylene glycol ether.

[0018] The coolant prepared by this invention can be applied to the thermal management system of new energy vehicles.

[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: The coolant additive composition and coolant of this invention, through low ion concentration design, nanocomposite thermally conductive network construction, and innovative bio-based anti-corrosion system, overcome the common problems of low thermal conductivity and easy corrosion in coolants, providing a green solution for the thermal management system of new energy vehicles that combines insulation, efficient heat dissipation, and long lifespan. The core technology of this invention lies in combining MOF nanomaterials, bio-based polymers, and environmentally friendly ionic liquids to achieve synergistic optimization across multiple performance dimensions, aligning with the development trend of "safe, efficient, and sustainable" thermal management materials in the new energy field. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The coolant additive composition and coolant in the examples are prepared by the following steps:

[0022] Step 1: Raw material pretreatment

[0023] Deionized water treatment: Weigh out 50% of the total deionized water for later use, and use the remaining 50% for subsequent volume adjustment.

[0024] Preparation of nanoparticle dispersion: Deionized water was added to a glass container, and an ultrasonic disperser was turned on. ZIF-8@ellagic acid nanoparticles were slowly added, and ultrasonic dispersion was carried out for 45 minutes until the solution was uniformly brownish-yellow and no visible precipitate was observed. Graphene oxide chitosan was added, and ultrasonic dispersion was continued for 30 minutes to form a stable colloid.

[0025] Dissolving functional additives: Dissolve vitamin E acetate in anhydrous ethanol and stir until completely transparent.

[0026] Step 2: Mixing and dispersing the main liquid

[0027] Ethylene glycol-polyethylene glycol blending: Add ethylene glycol to a stainless steel reactor and start stirring (300 rpm). Slowly add polyethylene glycol, heat to 50°C, and stir for 30 minutes until completely miscible (the solution is clear and does not separate into layers).

[0028] Dispersed phase addition: The nanoparticle colloid obtained in step 1 was slowly poured into the reactor and stirred continuously (400 rpm) for 1 hour, during which time the system was observed for agglomeration. N-trimethyl chitosan was added and stirred for 20 minutes to stabilize the nanoparticle interface by cationic charge adsorption.

[0029] Antioxidant and pH adjustment: Pour in vitamin E ethanol solution and stir for 15 minutes until the ethanol has completely evaporated.

[0030] Prepare a 1% sodium citrate aqueous solution and add it dropwise to the reaction vessel while monitoring the pH value with a pH meter and adjusting the pH value.

[0031] Step 3: Volume adjustment, defoaming and filtration

[0032] Volume adjustment and defoaming: Add the remaining 50% of deionized water and stir for 30 minutes. Add polyethylene glycol ether defoamer, reduce the speed to 100 rpm, stir for 10 minutes, and then let stand for degassing for 30 minutes.

[0033] Precision filtration: The solution is filtered through a 0.22μm polyvinylidene fluoride (PVDF) filter membrane to remove micron-sized particles and residual ionic impurities. The transmittance of the filtered solution is >98%.

[0034] Example 1

[0035] A coolant comprising the following components in parts by weight: 50 parts ethylene glycol; 46.5 parts deionized water; 0.8 parts ZIF-8@ellagic acid nanoparticles; 0.3 parts graphene oxide chitosan; 2.0 parts polyethylene glycol; 0.2 parts N-trimethyl chitosan; 0.1 parts vitamin E acetate; 0.05 parts sodium citrate; and 0.05 parts polyethylene glycol ether.

[0036] Example 2

[0037] A coolant additive comprises the following components in parts by weight: 55 parts ethylene glycol; 41.7 parts deionized water; 0.6 parts ZIF-8@ellagic acid nanoparticles; 0.2 parts graphene oxide chitosan; 3.0 parts polyethylene glycol; 0.3 parts N-trimethyl chitosan; 0.1 parts vitamin E acetate; 0.03 parts sodium citrate; and 0.05 parts polyethylene glycol ether.

[0038] Example 3

[0039] A coolant comprising the following components in parts by weight: 52 parts ethylene glycol; 44.2 parts deionized water; 1.2 parts ZIF-8@ellagic acid nanoparticles; 0.5 parts graphene oxide chitosan; 1.5 parts polyethylene glycol; 0.2 parts N-trimethyl chitosan; 0.2 parts vitamin E acetate; 0.05 parts sodium citrate; and 0.05 parts polyethylene glycol ether.

[0040] Example 4

[0041] A coolant comprising the following components in parts by weight: 50 parts ethylene glycol; 45.7 parts deionized water; 0.8 parts ZIF-8@ellagic acid nanoparticles; 0.4 parts graphene oxide chitosan; 2.5 parts polyethylene glycol; 0.3 parts N-trimethyl chitosan; 0.2 parts vitamin E acetate; 0.02 parts sodium citrate; and 0.05 parts polyethylene glycol ether.

[0042] Comparative Example 1

[0043] A commercially available brand of ethylene glycol-water coolant was purchased and tested under the same experimental conditions as the coolants in Examples 1 to 4.

[0044] To evaluate the thermal conductivity, static and dynamic corrosion resistance of the coolants in the comparative examples and embodiments, the present invention employs the following test methods:

[0045] 1. Thermal conductivity test

[0046] Instrument: Laser thermal conductivity meter (accuracy ±3%)

[0047] Method: The thermal conductivity of the original coolant at 25℃ was directly measured (unit: W / (m·K)).

[0048] Principle: The higher the thermal conductivity, the better the heat dissipation efficiency. Nanoparticles and graphene can improve thermal conductivity.

[0049] 2. Static corrosion performance test

[0050] Standard: ASTM D1384-24 "Standard Test Method for Corrosion Testing of Engine Coolant in Glassware"

[0051] Conditions: Metal specimens: copper (T2), brass (H62), aluminum 303 (Al-Mg-Si alloy), size 50mm×25mm×2mm;

[0052] Temperature: 100℃, Time: 72 hours;

[0053] Corrosion rate calculation: Corrosion rate mg / (cm²) 2 •h)) = Weight loss / (Area * Time)

[0054] 3. Dynamic corrosion performance test

[0055] Standard: ASTM D4340-19 "Determination of Corrosion of Cast Aluminum Alloys by Engine Coolant under Heat Transfer Conditions"

[0056] Conditions: Metal specimen: Same as static test;

[0057] Temperature: 120℃, circulation rate: 1.5m / s, time: 168 hours;

[0058] The corrosion rate is calculated in the same way as above.

[0059] The results of tests conducted on the coolant in Examples 1 to 4 and Comparative Example 1 are shown in the table below:

[0060]

[0061] As can be seen from the table above, the corresponding embodiments of the present invention have better thermal conductivity and corrosion resistance than the coolant in the comparative example under the same test conditions.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A coolant additive composition comprising a corrosion inhibitor, a thermal conductivity enhancer, a dispersant, and an antioxidant, characterized in that, The corrosion inhibitor is ZIF-8@ellagic acid nanoparticles, the thermal conductivity enhancer is graphene oxide chitosan, the dispersant includes polyethylene glycol and N-trimethyl chitosan, and the antioxidant is vitamin E acetate. The preparation method of the ZIF-8@ellagic acid nanoparticles includes the following steps: (1) Dissolve 200g of 2-methylimidazole in 200mL of methanol, add 10g of zinc nitrate, and stir at 60℃ for 30min to generate ZIF-8 precursor; (2) Add 5g ellagic acid and 2mL triethylamine, and sonicate for 2h to anchor ellagic acid in the ZIF-8 channel through coordination bonds. (3) The solvent was removed by vacuum distillation to obtain a light yellow powder of ellagic acid supported on a zeolite imidazole ester framework, which is ZIF-8@ellagic acid nanoparticles.

2. The coolant additive composition according to claim 1, characterized in that, Includes the following components by weight: ZIF-8@ellagic acid nanoparticles, 0.6–1.2 parts; 0.2–0.5 parts of graphene oxide chitosan; 1.5 to 3.0 parts of polyethylene glycol; 0.2–0.3 parts of N-trimethyl chitosan; Vitamin E acetate 0.1 to 0.2 parts.

3. The coolant additive composition according to claim 1, characterized in that, The ZIF-8@ellagic acid nanoparticles have a particle size of 80–120 nm.

4. A coolant, characterized in that, It includes ethylene glycol, deionized water, and the coolant additive composition of claim 1.

5. A coolant according to claim 4, characterized in that, The preparation process also requires the addition of a pH adjuster and a defoamer. The pH adjuster is sodium citrate, and the defoamer is polyethylene glycol ether.

6. A coolant according to claim 5, characterized in that, The composition includes the following components by weight: 50 parts ethylene glycol; 46.5 parts deionized water; 0.8 parts ZIF-8@ellagic acid nanoparticles; 0.3 parts graphene oxide chitosan; 2.0 parts polyethylene glycol; and 0.2 parts N-trimethyl chitosan. Vitamin E acetate 0.1 parts; sodium citrate 0.05 parts; polyethylene glycol ether 0.05 parts.

7. A coolant according to claim 5, characterized in that, The product comprises the following components by weight: 55 parts ethylene glycol; 41.7 parts deionized water; 0.6 parts ZIF-8@ellagic acid nanoparticles; 0.2 parts graphene oxide chitosan; 3.0 parts polyethylene glycol; and 0.3 parts N-trimethyl chitosan. Vitamin E acetate 0.1 parts; sodium citrate 0.03 parts; polyethylene glycol ether 0.05 parts.

8. A coolant according to claim 5, characterized in that, The product comprises the following components by weight: 52 parts ethylene glycol; 44.2 parts deionized water; 1.2 parts ZIF-8@ellagic acid nanoparticles; 0.5 parts graphene oxide chitosan; and 1.5 parts polyethylene glycol. 0.2 parts of N-trimethyl chitosan; Vitamin E acetate 0.2 parts; sodium citrate 0.05 parts; polyethylene glycol ether 0.05 parts.

9. A coolant according to claim 5, characterized in that, The product comprises the following components by weight: 50 parts ethylene glycol; 45.7 parts deionized water; 0.8 parts ZIF-8@ellagic acid nanoparticles; 0.4 parts graphene oxide chitosan; and 2.5 parts polyethylene glycol. 0.3 parts N-trimethyl chitosan; 0.2 parts vitamin E acetate; 0.02 parts sodium citrate; 0.05 parts polyethylene glycol ether.

10. The application of the coolant according to any one of claims 4 to 9 in the thermal management system of new energy vehicles.

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