High-insulativity water-based cooling liquid and preparation method thereof

Abstract

The invention discloses a high-insulativity water-based cooling liquid. The high-insulativity water-based cooling liquid comprises the following components in parts by weight: 25-40 parts of deionized water; 20 to 35 parts of ethylene glycol; 15 to 25 parts of propylene glycol; 5 to 15 parts of a high-insulation reinforcing agent; 0.02 to 0.1 part of a corrosion and scale inhibition compound agent; 0.2 to 1 part of an insulation stabilizer; 0.05 to 0.3 part of a copper corrosion inhibitor; 0.02 to 0.1 part of an aluminum corrosion inhibitor; 0.5 to 3 parts of a nonionic surfactant; according to the cooling liquid disclosed by the invention, the safety performance of the cooling liquid can be improved.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive liquid technology, and in particular to a highly insulating water-based coolant and its preparation method. Background Technology

[0002] With the rapid development of industries such as new energy power generation, ultra-high voltage power transmission, large data centers, and energy storage systems, power electronic equipment is iterating towards higher power, higher density, and miniaturization. The heat generated during operation is increasing dramatically, placing stringent demands on the heat dissipation efficiency, safety, and stability of cooling systems. Liquid cooling technology, due to its advantages such as high heat exchange efficiency and uniform temperature control, has become the core cooling solution for high-power power electronic equipment, data center servers, and energy storage systems. As the key medium in liquid cooling systems, the performance of the coolant directly determines the operational reliability and service life of the equipment. Currently, the coolants used in the market mainly include oil-based coolants and water-based coolants. Although oil-based coolants have certain insulating properties, they have drawbacks such as low heat exchange efficiency, high viscosity, poor environmental performance, and high maintenance costs, making them unsuitable for the high-efficiency cooling requirements of high-power-density equipment. Water-based coolants, on the other hand, have become the mainstream cooling medium choice due to their significant advantages such as high heat exchange coefficient, environmental friendliness and non-toxicity, low cost, and abundant resources. However, existing water-based coolants still face several technical bottlenecks under harsh operating conditions of high voltage and high power density: First, insufficient insulation performance. Most existing water-based coolants use ordinary deionized water as the base fluid, and the added functional additives easily introduce ionic impurities, resulting in high system conductivity (usually greater than 10 μS / cm) and low dielectric strength (generally less than 20 kV / mm). Under high voltage environments, this can easily lead to electrical short circuit risks, seriously threatening equipment safety. Second, poor chemical stability. There is a lack of effective ion control mechanisms and dedicated insulation enhancement systems. During long-term operation, ion dissolution and decomposition are prone to occur, leading to continuous degradation of insulation performance. Third, poor corrosion and scale inhibition effects. Existing products mostly use a single corrosion inhibitor and lack a stable pH buffer system. During long-term use, the pH value is prone to fluctuation, which can not only cause electrochemical corrosion of metal substrates (such as copper, aluminum, steel, and other commonly used materials in equipment), but also cause metal ions to dissolve and deposit as scale, blocking cooling channels, reducing heat dissipation efficiency, further increasing the risk of equipment failure, and shortening the service life of equipment. In addition, while some existing improved water-based coolants attempt to improve insulation performance by increasing the purity of the base fluid or adding insulating agents, they often neglect the synergistic optimization of chemical stability and corrosion and scale inhibition performance. Either the system becomes unstable due to incompatibility between the insulating enhancer and the corrosion inhibitor, or the insulation performance rapidly declines over time due to the lack of a long-term pH buffer mechanism. It is difficult to achieve a balance between high insulation, long-term chemical stability and excellent corrosion and scale inhibition effects. Therefore, under the harsh operating conditions of high-voltage, high-power-density equipment, there is an urgent need to develop a water-based coolant with extremely low conductivity, high dielectric strength, long-term chemical stability, and efficient corrosion and scale inhibition properties. This is to solve the technical problems of existing products, such as insufficient insulation, susceptibility to short circuits and electrochemical corrosion, and severe scaling, and to ensure long-term, highly reliable, and safe cooling operation of power electronic equipment, data center servers, and energy storage systems, thus meeting the urgent needs of industry development. Summary of the Invention

[0003] This invention provides a highly insulating water-based coolant that can improve the safety performance of the coolant.

[0004] To address the aforementioned technical problems, this invention provides a highly insulating water-based coolant, comprising the following components by weight: Deionized water: 25-40 parts; ethylene glycol: 20-35 parts; propylene glycol: 15-25 parts; high insulation enhancer: 5-15 parts; corrosion and scale inhibitor compound: 0.02-0.1 parts; insulation stabilizer: 0.2-1 parts; copper corrosion inhibitor: 0.05-0.3 parts; aluminum corrosion inhibitor: 0.02-0.1 parts; nonionic surfactant: 0.5-3 parts; pH adjuster: 0.3-1.5 parts.

[0005] As a preferred embodiment of the above technical solution, the deionized water contains Na... + +Cl - ≤0.1 ppm.

[0006] As a preferred embodiment of the above technical solution, the high insulation reinforcing agent is polydimethylsiloxane 5 cSt, ε=2.7, Na + ≤0.1 ppm.

[0007] As a preferred embodiment of the above technical solution, the high insulation reinforcing agent is composed of 0.1 to 0.5 parts by weight of triazole-silane conjugate, 0.02 to 0.1 parts by weight of perfluoroalkylphosphonic acid, and 0.2 to 1 parts by weight of mannitol.

[0008] As a preferred embodiment of the above technical solution, the insulation stabilizer is mannitol.

[0009] As a preferred embodiment of the above technical solution, the copper corrosion inhibitor is methylbenzotriazole.

[0010] As a preferred embodiment of the above technical solution, the aluminum corrosion inhibitor is a perfluoroalkylphosphonic acid.

[0011] As a preferred embodiment of the above technical solution, the nonionic surfactant is a polyether-modified siloxane, HLB 6-9.

[0012] As a preferred embodiment of the above technical solution, the pH adjuster is a 1:1 molar trihydroxyethylammonium-boric acid complex.

[0013] Another aspect of the present invention provides a method for preparing a high-insulation water-based coolant, comprising the following specific steps: adding deionized water, ethylene glycol, propylene glycol, a high insulation enhancer, a corrosion and scale inhibitor compound, an insulation stabilizer, a copper corrosion inhibitor, an aluminum corrosion inhibitor, a nonionic surfactant, and a pH adjuster sequentially under nitrogen protection, stirring at 25 °C at a uniform speed for 30 min until completely dissolved, and filtering through a 0.1 µm PTFE filter element to obtain the high-insulation water-based coolant.

[0014] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Detailed Implementation

[0015] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0016] Example 1: The components were prepared according to the following mass ratio. Deionized water (electronic grade, Na) + +Cl - ≤0.1 ppm): 32.5 portions; Ethylene glycol (electronic grade): 27.5 parts; Propylene glycol (electronic grade): 20 parts; High insulation reinforcing agent (polydimethylsiloxane 5 cSt, ε=2.7, Na) + ≤0.1 ppm): 10 portions; Corrosion and scale inhibitor compound (nonionic type, composed of 0.3 parts triazole-silane conjugate, 0.06 parts perfluoroalkylphosphonic acid, and 0.6 parts mannitol): 0.96 parts; Insulation stabilizer (mannitol, also a complexing scale inhibitor): 0.6 parts; Copper corrosion inhibitor (methylbenzotriazole): 0.17 parts; Aluminum corrosion inhibitor (perfluoroalkylphosphonic acid, used in conjunction with the above): 0.06 parts; Nonionic surfactant (polyether-modified siloxane, HLB 6-9): 1.7 parts; pH adjuster (trihydroxyethylammonium-boric acid complex 1:1 molar): 0.9 parts, to maintain the pH of the system at 8.5-9.0.

[0017] The above materials are added sequentially under nitrogen protection, stirred at 25 °C at a constant speed for 30 min until completely dissolved, and then filtered through a 0.1 µm PTFE filter to obtain the high-insulation electronic coolant.

[0018] The resulting coolant exhibits the following properties at 25 °C: conductivity 0.38 µS / cm. -1 Dielectric strength 65 kV mm -1 pH 8.7; T2 copper, 6061 aluminum, and SS304 stainless steel specimens were completely immersed in an 80 ℃ coolant for 336 h. The mass loss was: copper 0.2 mg cm⁻¹ -2 Aluminum 0.3 mg cm -2 Stainless steel 0 mg cm -2 ; After continuous aging at 135 ℃ for 1000 h, the conductivity increased by ≤0.05 µS cm. -1 No precipitate was formed; After continuous operation for 500 hours on a live module at 85 ℃ / 85 %RH, the insulation resistance remained >10 GΩ and no corrosion spots were observed.

[0019] Example 2: The components were prepared according to the following mass ratios. Deionized water (electronic grade, Na) + +Cl - ≤0.1 ppm): 25 portions; Ethylene glycol (electronic grade): 35 parts; Propylene glycol (electronic grade): 25 parts; High insulation reinforcing agent (polydimethylsiloxane 5 cSt, ε=2.7, Na) + ≤0.1 ppm): 5 portions; Corrosion and scale inhibitor compound (nonionic type, composed of 0.5 parts triazole-silane conjugate, 0.1 parts perfluoroalkylphosphonic acid, and 1 part mannitol): 1.6 parts; Insulation stabilizer (mannitol): 1 part; Copper corrosion inhibitor (methylbenzotriazole): 0.3 parts; Aluminum corrosion inhibitor (perfluoroalkylphosphonic acid): 0.1 parts; Nonionic surfactant (polyether-modified siloxane, HLB 6-9): 3 parts; pH adjuster (trihydroxyethylammonium-boric acid complex 1:1 molar): 1.5 parts, to maintain the system pH at 8.5-9.0.

[0020] Under nitrogen protection, the materials were added sequentially, stirred at a constant speed at 25 °C for 30 min, and filtered through a 0.1 µm PTFE filter element to obtain a high-insulation coolant.

[0021] Performance at 25 °C: Conductivity 0.35 µS cm -1 Dielectric strength 68 kV mm -1 pH 8.9; Immersion at 80 ℃ for 336 h: Copper weight loss 0.15 mg cm -2 Aluminum weight loss: 0.25 mg / cm³ -2 Stainless steel weight loss 0 mgcm -2 ; After aging at 135 ℃ for 1000 h, the conductivity increased by ≤0.04 µS cm⁻¹. -1 No sediment; After 500 hours of operation at 85 ℃ / 85 %RH with the module energized, the insulation resistance was >12 GΩ and no corrosion spots were observed.

[0022] Example 3: The components were prepared according to the following mass ratios. Deionized water (electronic grade, Na) + +Cl - ≤0.1 ppm): 40 portions; Ethylene glycol (electronic grade): 20 parts; Propylene glycol (electronic grade): 15 parts; High insulation reinforcing agent (polydimethylsiloxane 5 cSt, ε=2.7, Na) + ≤0.1 ppm): 15 portions; Corrosion and scale inhibitor compound (nonionic type, composed of 0.1 parts triazole-silane conjugate, 0.02 parts perfluoroalkylphosphonic acid, and 0.2 parts mannitol): 0.32 parts; Insulation stabilizer (mannitol): 0.2 parts; Copper corrosion inhibitor (methylbenzotriazole): 0.05 parts; Aluminum corrosion inhibitor (perfluoroalkylphosphonic acid): 0.02 parts; Nonionic surfactant (polyether-modified siloxane, HLB 6-9): 0.5 parts; pH adjuster (trihydroxyethylammonium-boric acid complex 1:1 molar): 0.3 parts, to maintain the system pH at 8.5-9.0.

[0023] The coolant was prepared using the same process as in Example 2.

[0024] Performance at 25 °C: Conductivity 0.42 µS cm -1 Dielectric strength 62 kV mm -1 pH 8.5; Immersion at 80 ℃ for 336 h: Copper weight loss 0.18 mg cm -2 Aluminum weight loss: 0.28 mg / cm³ -2 Stainless steel weight loss 0 mgcm -2 ; After aging at 135 ℃ for 1000 h, the conductivity increased by ≤0.06 µS cm. -1 No sediment; After 500 hours of operation at 85℃ / 85%RH with the module energized, the insulation resistance was >9 GΩ and there were no corrosion spots.

[0025] Example 4: The components were prepared according to the following mass ratios. Deionized water (electronic grade, Na) + +Cl - ≤0.1 ppm): 30 portions; Ethylene glycol (electronic grade): 30 parts; Propylene glycol (electronic grade): 22 parts; High insulation reinforcing agent (polydimethylsiloxane 5 cSt, ε=2.7, Na) + ≤0.1 ppm): 8 portions; Corrosion and scale inhibitor compound (nonionic type, composed of 0.35 parts of triazole-silane conjugate, 0.07 parts of perfluoroalkylphosphonic acid, and 0.8 parts of mannitol): 1.22 parts; Insulation stabilizer (mannitol): 0.8 parts; Copper corrosion inhibitor (methylbenzotriazole): 0.2 parts; Aluminum corrosion inhibitor (perfluoroalkylphosphonic acid): 0.07 parts; Nonionic surfactant (polyether-modified siloxane, HLB 6-9): 2 parts; pH adjuster (trihydroxyethylammonium-boric acid complex 1:1 molar): 1.0 part, to maintain the system pH at 8.5-9.0.

[0026] The coolant was prepared using the same process as in Example 2.

[0027] Performance at 25 °C: Conductivity 0.37 µS cm -1 Dielectric strength 66 kV mm -1 pH 8.8; Immersion at 80 ℃ for 336 h: Copper weight loss 0.12 mg cm -2 Aluminum weight loss: 0.22 mg / cm³-2 Stainless steel weight loss 0 mgcm -2 ; After aging at 135 ℃ for 1000 h, the conductivity increased by ≤0.04 µS cm⁻¹. -1 No sediment; After 500 hours of operation at 85℃ / 85%RH with the module energized, the insulation resistance was >11 GΩ and no corrosion spots were observed.

[0028] The principle behind the above embodiments is as follows: In high-voltage, high-power-density liquid cooling systems, the coolant of this invention, with its high-purity base fluid and high-insulation-enhancing agent polydimethylsiloxane, constructs an electrically insulating environment with an overall low dielectric constant and extremely low ion concentration. The high-insulation-enhancing agent has an extremely low dielectric constant, which can significantly increase the breakdown voltage of the fluid, essentially blocking the current path. Simultaneously, the buffer system composed of the pH adjuster trihydroxyethylammonium-boric acid complex can stabilize the coolant environment within the optimal weakly alkaline range of pH 8.5~9.0, which effectively inhibits the corrosion of all metals. The corrosion and scale inhibitor compound and the insulation stabilizer mannitol work synergistically to capture and stabilize trace metal ions that may be generated during operation through molecular adsorption, chemical complexation, and steric hindrance, preventing them from forming conductive deposits or undergoing catalytic degradation, thereby maintaining the system's ultra-high insulation resistance over the long term.

[0029] Mannitol, an insulation stabilizer, is a polyol with excellent water solubility, strong complexing ability, and high thermal stability. Its core function is dual stabilization: in solution, it can strongly complex free metal ions, preventing them from catalytic oxidation and forming conductive bridges; at the interface, it can strengthen the corrosion inhibition film, working together with composite corrosion inhibitors to ensure the long-term stability of the metal substrate. It is a key functional component for maintaining the insulation performance without degradation.

[0030] This results in a coolant with excellent electrical insulation properties and long-term chemical stability. In cooling equipment, the coolant, with its high resistance and high dielectric strength, can operate safely under high voltage conditions, effectively preventing electrochemical corrosion and short-circuit risks. Even during prolonged high-temperature cycling in equipment, its unique corrosion inhibition and pH stabilization mechanisms continuously suppress metal ion dissolution and scale formation, preventing insulation performance degradation over time. This results in a coolant with superior insulation performance, long-term stability, and the ability to ensure the safe operation of high-power power electronic equipment.

[0031] Comparative Example 1: Deionized water (standard grade, Na) + +Cl - ≈1.2 ppm): 45 portions; Ethylene glycol (industrial grade): 45 parts; Commercially available general-purpose corrosion inhibitor (compound of sodium silicate + borax + sodium benzoate): 2 parts; Benzotriazole: 0.2 parts; Sodium hydroxide: Adjust pH to 9.0.

[0032] Dissolve by stirring at room temperature, filter through a 0.45 µm PP filter to obtain the control coolant.

[0033] Performance at 25 °C: Conductivity 8.7 µS cm -1 Its dielectric strength is only 12 kV mm. -1 pH 9.0; Immersion at 80 ℃ for 336 h: Copper weight loss 1.8 mg cm -2 Aluminum weight loss 3.4 mg / cm³ -2 Stainless steel weight loss: 0.6 mgcm -2 Obvious pitting corrosion was visible on the surface of the sample. A white precipitate appeared after aging at 135 ℃ for 168 h, and the conductivity soared to 18 µS cm. -1 ; The insulation resistance of the energized module at 85 ℃ / 85 %RH dropped sharply (<0.3 GΩ) after only 72 hours of operation, and copper patina and aluminum corrosion spots appeared inside the module, leading to a short circuit and shutdown.

[0034] The high-insulation coolant involved in this invention provides fundamental electrical safety assurance through its extremely low conductivity and high breakdown voltage during normal use in liquid cooling equipment. Its core lies in the creation of an ion-clean, interface-stable, and chemically buffered "insulating microenvironment" through careful material selection and synergistic formulation. This addresses the insulation and corrosion control challenges of liquid cooling systems from three levels: source, process, and long-term stability, thereby achieving long-term safe cooling for power electronic equipment.

[0035] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A highly insulating water-based coolant, characterized in that, Each component, by weight, includes: Deionized water: 25-40 parts; ethylene glycol: 20-35 parts; propylene glycol: 15-25 parts; high insulation enhancer: 5-15 parts; corrosion and scale inhibitor compound: 0.02-0.1 parts; insulation stabilizer: 0.2-1 parts; copper corrosion inhibitor: 0.05-0.3 parts; aluminum corrosion inhibitor: 0.02-0.1 parts; nonionic surfactant: 0.5-3 parts; pH adjuster: 0.3-1.5 parts.

2. The high-insulation water-based coolant according to claim 1, characterized in that, The Na of the deionized water + +Cl - ≤0.1 ppm.

3. The high-insulation water-based coolant according to claim 1, characterized in that, The high insulation reinforcing agent is polydimethylsiloxane 5 cSt, ε=2.7, Na + ≤0.1 ppm.

4. The high-insulation water-based coolant according to claim 1, characterized in that, The high insulation enhancer is composed of 0.1 to 0.5 parts by weight of triazole-silane conjugate, 0.02 to 0.1 parts by weight of perfluoroalkylphosphonic acid, and 0.2 to 1 parts by weight of mannitol.

5. The high-insulation water-based coolant according to claim 1, characterized in that, The insulation stabilizer is mannitol.

6. The high-insulation water-based coolant according to claim 1, characterized in that, The copper corrosion inhibitor is methylbenzotriazole.

7. The high-insulation water-based coolant according to claim 1, characterized in that, The aluminum corrosion inhibitor is a perfluoroalkylphosphonic acid.

8. The high-insulation water-based coolant according to claim 1, characterized in that, The nonionic surfactant is a polyether-modified siloxane, HLB 6-9.

9. The high-insulation water-based coolant according to claim 1, characterized in that, The pH adjuster is a 1:1 molar trihydroxyethylammonium-boronic acid complex.

10. A method for preparing a highly insulating water-based coolant, characterized in that, The specific steps include: adding deionized water, ethylene glycol, propylene glycol, high insulation enhancer, corrosion and scale inhibitor compound, insulation stabilizer, copper corrosion inhibitor, aluminum corrosion inhibitor, nonionic surfactant, and pH adjuster sequentially under nitrogen protection, stirring at 25 ℃ for 30 min until completely dissolved, and filtering through a 0.1 µm PTFE filter to obtain the high insulation water-based coolant.