Hydrogen fuel cell cooling liquid and preparation method thereof

Abstract

The invention relates to the technical field of hydrogen fuel cells, and discloses hydrogen fuel cell cooling liquid and a preparation method thereof. The hydrogen fuel cell cooling liquid is prepared from the following substances in parts by weight: 60 to 90 parts by weight of water, 5 to 20 parts by weight of carbon nano modified propylene glycol ether, 0.5 to 5 parts by weight of 1-butyl-3-methylimidazolium tetrafluoroborate, 3 to 12 parts by weight of polyethylene glycol, 0.5 to 5 parts by weight of organic boric acid ester, 0.1 to 3 parts by weight of polyacrylic acid, 0.1 to 0.8 part by weight of quaternary ammonium salt and 0.01 to 0.4 part by weight of silver nanoparticles. The hydrogen fuel cell cooling liquid provided by the invention has multiple functions of freezing prevention, cooling, corrosion prevention, scale prevention, bacteria prevention and the like, and also has the characteristics of low conductivity and high membrane electrode compatibility.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to a hydrogen fuel cell coolant and a preparation method thereof. Background Art

[0002] As the global energy crisis and environmental pollution become increasingly serious, the development and utilization of clean energy has become a common focus of attention for countries around the world. As an efficient and clean energy conversion device, hydrogen fuel cells have attracted much attention due to their zero emissions and high energy density. However, in actual application, the performance and life of hydrogen fuel cells are affected by many factors, among which the choice of coolant is particularly critical.

[0003] Traditional alcohol coolants, such as methanol and ethanol, have long been widely used in hydrogen fuel cells due to their good thermal conductivity and compatibility with fuel cell materials. This type of coolant can effectively take away the heat generated by the fuel cell, ensuring that the battery operates at a suitable temperature, thereby maintaining its stability and efficiency. However, there are also some problems with alcohol coolants that cannot be ignored. First, they are flammable substances. Once they leak or encounter a fire source, they are very likely to cause safety accidents and bring potential dangers to users. Secondly, alcohol coolants are harmful to the environment. Long-term use will cause pollution to water and soil, which is not conducive to the protection of the ecological environment. In addition, the vapor pressure of alcohol coolants is high, which can easily lead to evaporation losses of coolants, which not only increases maintenance costs, but may also affect the normal operation of fuel cells.

[0004] Based on this, it is of great significance to provide a non-alcohol hydrogen fuel cell coolant that is environmentally friendly, highly safe, has good thermal conductivity, good thermal stability and good material compatibility. Summary of the invention

[0005] The purpose of the present invention is to provide a hydrogen fuel cell coolant which has multiple functions such as antifreeze, cooling, corrosion prevention, scale prevention, and antibacterial, and has the characteristics of low conductivity and high membrane electrode compatibility.

[0006] In order to achieve the above object, the first aspect of the present invention provides a hydrogen fuel cell coolant, which is composed of the following substances in parts by weight: 60-90 parts by weight of water, 5-20 parts by weight of carbon nano-modified propylene glycol ether, 0.5-5 parts by weight of 1-butyl-3-methylimidazole tetrafluoroborate, 3-12 parts by weight of polyethylene glycol, 0.5-5 parts by weight of organic borate, 0.1-3 parts by weight of polyacrylic acid, 0.1-0.8 parts by weight of quaternary ammonium salt, and 0.01-0.4 parts by weight of silver nanoparticles; The average volume diameter of the silver nanoparticles is 20-80 nm; The carbon nanotube-modified propylene glycol ether is a product prepared by a method comprising the following steps: The pretreated carbon nanotubes are brought into contact and mixed with propylene glycol ether, and then the carbon nanotube-modified propylene glycol ether is obtained through ultrasonic treatment; The pretreated carbon nanotubes are a product prepared by a method comprising the following steps: S1. The carbon nanotubes are soaked in an acid pickling solution for 1 - 3 h to obtain mixture I; S2. The mixture I is heated to 100 - 120 °C and refluxed for 2 - 5 h, and then washed with deionized water to obtain mixture II; S3. The mixture II is subjected to a first reaction with a titanate coupling agent solution, and then calcined at 800 - 900 °C for 1 - 2 h under an inert gas to obtain the pretreated carbon nanotubes.

[0007] In a second aspect of the present invention, a method for preparing a hydrogen fuel cell coolant is provided. This method is carried out using the substances in the hydrogen fuel cell coolant described in the first aspect. This method includes: (1) Water and the carbon nanotube-modified propylene glycol ether are mixed for a first contact to obtain premixed liquid I; (2) The premixed liquid I and 1-butyl-3-methylimidazolium tetrafluoroborate are mixed for a second contact to obtain premixed liquid II; (3) Polyethylene glycol, polyacrylic acid, and organic borate ester are mixed with the premixed liquid II for a third contact to obtain premixed liquid III; (4) Under ultrasonic conditions, the premixed liquid III and quaternary ammonium salt and silver nanoparticles are mixed for a fourth contact. After adjusting the pH, impurities are removed through an ultra-fine filtration device, and then a hydrogen fuel cell coolant is obtained through ion exchange; Among them, the dosages of each substance are as follows: 60 - 90 parts by weight of water, 5 - 20 parts by weight of the carbon nanotube-modified propylene glycol ether, 0.5 - 5 parts by weight of 1-butyl-3-methylimidazolium tetrafluoroborate, 3 - 12 parts by weight of polyethylene glycol, 0.5 - 5 parts by weight of organic borate ester, 0.1 - 3 parts by weight of polyacrylic acid, 0.1 - 0.8 parts by weight of quaternary ammonium salt, and 0.01 - 0.4 parts by weight of silver nanoparticles.

[0008] In a third aspect of the present invention, a hydrogen fuel cell coolant prepared by the method described in the second aspect is provided.

[0009] Compared with the prior art, the method provided by the present invention has at least the following beneficial effects: (1)The hydrogen fuel cell coolant provided by the present invention has low electrical conductivity and is non-flammable, improving the overall safety of the hydrogen fuel cell system. Moreover, while optimizing the anti-corrosion and antibacterial properties, it also enhances the heat conduction ability of the coolant, effectively improving the heat dissipation efficiency of the hydrogen fuel cell system and ensuring the stability and lifespan of the battery under high-temperature working conditions. It reduces the evaporation loss of the coolant, lowers the maintenance frequency and cost of the cooling system, and simultaneously increases the service life of the coolant. It has good compatibility with other materials in the hydrogen fuel cell system, reducing corrosion and pollution problems and maintaining the performance of the battery. (2)In the method provided by the present invention, polyethylene glycol, polyacrylic acid, and organic borate can produce a synergistic effect, and the subsequently added quaternary ammonium salt can interact with these polymer systems, thereby increasing the surface activity, stability, temperature resistance, and conductivity of the system. (3)In the method provided by the present invention, silver nanoparticles can interact with the cationic part of the quaternary ammonium salt, causing changes in the surface properties of the silver nanoparticles to form stable nano-complexes, and simultaneously changing the release rate of silver ions, thereby effectively inhibiting bacteria and molds and enhancing the antibacterial property and stability of the system. Detailed implementation manners

[0010] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0011] As described above, the first aspect of the present invention provides a hydrogen fuel cell coolant, which is composed of the following substances in parts by weight: 60 - 90 parts by weight of water, 5 - 20 parts by weight of carbon nanotube-modified propylene glycol ether, 0.5 - 5 parts by weight of 1-butyl-3-methylimidazolium tetrafluoroborate, 3 - 12 parts by weight of polyethylene glycol, 0.5 - 5 parts by weight of organic borate, 0.1 - 3 parts by weight of polyacrylic acid, 0.1 - 0.8 parts by weight of quaternary ammonium salt, and 0.01 - 0.4 parts by weight of silver nanoparticles; The average volume diameter of the silver nanoparticles is 20 - 80 nm; The carbon nanotube-modified propylene glycol ether is a product prepared by a method including the following steps: Contact and mix the pretreated carbon nanotubes with propylene glycol ether, and then obtain the carbon nanotube-modified propylene glycol ether through ultrasonic treatment; The pretreated carbon nanotubes are a product prepared by a method including the following steps: S1. Immerse carbon nanoparticles in the pickling solution for 1 - 3 h to obtain mixture I; S2. Heat the mixture I to 100 - 120 °C and reflux for 2 - 5 h, then wash with deionized water to obtain mixture II; S3. React the mixture II with the titanate coupling agent solution in the first reaction, and then calcine at 800 - 900 °C for 1 - 2 h under an inert gas to obtain the pretreated carbon nanoparticles.

[0012] Preferably, the weight ratio of the carbon nanotube - modified propylene glycol ether to the 1 - butyl - 3 - methylimidazolium tetrafluoroborate is 4 - 9:1. In this preferred case, the thermal conductivity and electrochemical stability of the coolant can be significantly improved.

[0013] Preferably, the organic borate ester is glycerol borate or triethanolamine borate.

[0014] Preferably, the quaternary ammonium salt is cetyltrimethylammonium bromide or benzalkonium chloride.

[0015] Preferably, the weight ratio of the quaternary ammonium salt to the silver nanoparticles is 2 - 8:1. In this preferred case, the antibacterial and anticorrosive properties of the coolant can be effectively enhanced.

[0016] Preferably, the weight ratio of the pretreated carbon nanoparticles to the propylene glycol ether is 10 - 20:100.

[0017] Preferably, the ultrasonic treatment is carried out under stirring, and at least meets: the rotation speed is 400 - 600 rpm, the power is 300 - 500 W, and the time is 10 - 20 min.

[0018] Preferably, in step S1, the pickling solution is a mixture of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1.

[0019] Preferably, in step S3, the titanate coupling agent solution is an ethanol solution of the titanate coupling agent, and the concentration is 0.5 - 2.0 wt%.

[0020] It should be noted that in the present invention, the water is deionized water and / or distilled water.

[0021] As described above, the second aspect of the present invention provides a method for preparing a hydrogen fuel cell coolant, which uses the substances in the hydrogen fuel cell coolant described in the first aspect. The method includes: (1) Mix water and carbon nanotube - modified propylene glycol ether for the first contact to obtain premixed liquid I; (2) Mix the premixed liquid I with 1 - butyl - 3 - methylimidazolium tetrafluoroborate for the second contact to obtain premixed liquid II; (3) Mix polyethylene glycol, polyacrylic acid, organic borate ester with the premixed solution II for the third contact to obtain premixed solution III; (4) Under ultrasonic conditions, mix the premixed solution III with quaternary ammonium salt and silver nanoparticles for the fourth contact. After adjusting the pH, remove impurities through an ultra-fine filtration device, and then obtain a hydrogen fuel cell coolant through ion exchange; Among them, the dosage of each substance is as follows: 60 - 90 parts by weight of water, 5 - 20 parts by weight of carbon nanotube-modified propylene glycol ether, 0.5 - 5 parts by weight of 1-butyl-3-methylimidazolium tetrafluoroborate, 3 - 12 parts by weight of polyethylene glycol, 0.5 - 5 parts by weight of organic borate ester, 0.1 - 3 parts by weight of polyacrylic acid, 0.1 - 0.8 parts by weight of quaternary ammonium salt, and 0.01 - 0.4 parts by weight of silver nanoparticles.

[0022] It should be noted that the present invention has no special requirements for the ultra-fine filtration device and ion exchange resin, and conventional technical means in the art can be used. Exemplarily, the filtration accuracy of the ultra-fine filtration device is 1 μm, and the ion exchange can be carried out using Rohm and Haas AMBERJET UP6040 ion exchange resin.

[0023] Preferably, the method of the present invention is carried out under the condition of 20 - 50 °C.

[0024] Preferably, the temperatures of the second contact and the third contact are each independently 28 - 50 °C.

[0025] Preferably, the temperature of the fourth contact is 20 - 35 °C.

[0026] According to a preferred embodiment, in step (2), the first contact, the second contact, the third contact, and the fourth contact are all carried out under stirring conditions, and each independently satisfies at least: the rotation speed is 400 - 600 rpm, and the time is 20 - 50 min.

[0027] Preferably, in step (4), the power of the ultrasonic condition is 400 - 500 W.

[0028] Preferably, in step (4), the pH adjustment is carried out using a boric acid buffer solution or a phosphate buffer solution, and the adjusted pH is 7.5 - 8.5.

[0029] As described above, the third aspect of the present invention provides a hydrogen fuel cell coolant prepared by the method described in the second aspect above.

[0030] The present invention is described in detail below through examples. Without special instructions, the raw materials used are all ordinary commercially available products.

[0031] Unless otherwise specified, each "part by weight" in the present invention represents 10 g.

[0032] Silver nanoparticles: average volume diameter is 60 nm.

[0033] Organic borate ester: triethanolamine borate ester (CAS No.: 283-56-7), effective ingredient content is 99 wt%, purchased from Shandong Huian Chemical Co., Ltd.; Quaternary ammonium salt: cetyltrimethylammonium bromide (CTAB, CAS No.: 57-09-0), effective ingredient content is 99 wt%, purchased from Henan Minghui Chemical Products Co., Ltd.

[0034] Preparation Example A-1 Prepare pretreated carbon nanoparticles: S1. Immerse carbon nanoparticles in a pickling solution (a mixture of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1) for 1.5 h to obtain Mixture I; S2. Heat the Mixture I to 100 °C and reflux for 3 h, wash it with deionized water until neutral to obtain Mixture II; S3. React the Mixture II with an ethanol solution (concentration is 1.0 wt%) of the titanate coupling agent, and then calcine it at 800 °C for 2 h in an inert gas to obtain pretreated carbon nanoparticles, named a1.

[0035] Preparation Example B-1 Add 10.5 g of pretreated carbon nanoparticles (a1) to propylene glycol ether at a weight ratio of 15:100 for contact mixing, and then perform ultrasonic treatment (rotation speed is 500 rpm, power is 300 W, time is 15 min) under stirring conditions to obtain the carbon nanotube-modified propylene glycol ether, named b1.

[0036] Preparation Example B-2 Add 10.5 g of pretreated carbon nanoparticles (a1) to propylene glycol ether at a weight ratio of 25:100 for contact mixing, and then perform ultrasonic treatment (rotation speed is 500 rpm, power is 300 W, time is 15 min) under stirring conditions to obtain the carbon nanotube-modified propylene glycol ether, named b2.

[0037] Preparation Example B-3 Directly add 10.5 g of un-pretreated carbon nanoparticles in Preparation Example A-1 to propylene glycol ether at a weight ratio of 15:100 for contact mixing, and then perform ultrasonic treatment (rotation speed is 500 rpm, power is 300 W, time is 15 min) under stirring conditions to obtain the carbon nanotube-modified propylene glycol ether, named b3.

[0038] Preparation Example C-1 This preparation example is used to illustrate the preparation of the hydrogen fuel cell coolant provided by the present invention, which is carried out according to the following steps: (1) At 20 °C, carbon nanotube-modified propylene glycol ether (b1) was added to water at a rotation speed of 400 rpm and mixed and stirred for 25 min for the first contact to obtain premixed liquid I; (2) At 28 °C, the premixed liquid I was mixed and stirred with 1-butyl-3-methylimidazolium tetrafluoroborate at a rotation speed of 400 rpm for 25 min for the second contact to obtain premixed liquid II; (3) At 28 °C, polyethylene glycol, polyacrylic acid, organic borate ester were mixed and stirred with the premixed liquid II at a rotation speed of 400 rpm for 50 min for the third contact to obtain premixed liquid III; (4) At 20 °C and under ultrasonic conditions (power 500 W), the premixed liquid III was mixed and stirred with quaternary ammonium salt and silver nanoparticles (silver nanoparticles I) at a rotation speed of 400 rpm for 30 min for the fourth contact. After adjusting the pH to 7.5 with phosphate buffer solution, impurities were removed by an ultra-fine filtration device (filtration accuracy of 1 μm), and then after ion exchange (using Rohm and Haas AMBERJET UP6040 ion exchange resin), the hydrogen fuel cell coolant was obtained, named P1; Among them, the dosages of each substance are: 82 parts by weight of water, 8 parts by weight of carbon nanotube-modified propylene glycol ether, 2 parts by weight of 1-butyl-3-methylimidazolium tetrafluoroborate, 4 parts by weight of polyethylene glycol, 2 parts by weight of organic borate ester, 1.5 parts by weight of polyacrylic acid, 0.4 parts by weight of quaternary ammonium salt, and 0.1 parts by weight of silver nanoparticles.

[0039] Preparation Example C-2 This preparation example was carried out in a similar manner to Preparation Example C-1, except that the dosages of carbon nanotube-modified propylene glycol ether and 1-butyl-3-methylimidazolium tetrafluoroborate were 5 parts by weight and 5 parts by weight respectively; Finally, a hydrogen fuel cell coolant was obtained, named P2.

[0040] Preparation Example C-3 This preparation example was carried out in a similar manner to Preparation Example C-1, except that in step (1), the carbon nanotube-modified propylene glycol ether used was b2; Finally, a hydrogen fuel cell coolant was obtained, named P3.

[0041] Comparative Example A This comparative example was carried out in a similar manner to Preparation Example C-1, except that in step (1), an equal mass of propylene glycol ether was used instead of carbon nanotube-modified propylene glycol ether for the first contact; Finally, a hydrogen fuel cell coolant was obtained, named D1.

[0042] Comparative Example B This comparative example was carried out by a method similar to that of Preparation Example C-1. The difference is that in step (1), the carbon nanotube-modified propylene glycol ether used was b3; Finally, a hydrogen fuel cell coolant was obtained and named D2.

[0043] Test Example 1 The hydrogen fuel cell coolants prepared in the above example part were subjected to the following performance tests, including: Antifreeze performance: Tested in accordance with the standard "SH / T 0090"; Conductivity: Tested with a conductivity meter in accordance with the standard "GB / T 11446.4 Test Method for Resistivity of Electronic Grade Water"; Measurement of thermal conductivity: The thermal conductivity at 60 °C; Ion inhibition performance: Tested in accordance with the aluminum, steel, and brass metal specimens and the metal specimen cleaning method specified in "SH / T 0085". The metal specimens were immersed in the solution without forming an electric couple. The test temperature was raised to 150 °C, and the test period was 168 h. The metal corrosion of the test sample was tested to reflect the metal ion inhibition ability; Proton exchange membrane compatibility performance: Tested for proton conductivity in accordance with the standard "GB / T 20042.3". Before the test, the proton exchange membrane was immersed in the coolant at 80 °C ± 2 °C for 1 h, and then the proton conductivity was measured. If the decrease was more than 5% of the original value, it was unqualified; if the decrease was ≤ 5% of the original value, it was qualified.

[0044] Stability test: The hydrogen fuel cell coolant was sealed and stored at 55 °C for 15 days, and the time of turbidity appearance was recorded in days. If no turbidity phenomenon occurred after 15 days of storage, it was recorded as "none".

[0045] Antibacterial property test: Take the recycled tap water used in the factory workshop for 2 weeks as the blank water sample, dilute it with the coolant at a ratio of 1:1 respectively, culture it at 35 °C for 48 h, and refer to the standard "SY / T 5329-1994". The antibacterial rates of saprophytic bacteria, sulfate-reducing bacteria, and iron bacteria on the 7th day were detected by the extinction dilution and three-repetition method, and then the average value of the three was recorded as the result.

[0046] The specific test results are shown in Table 1; As can be seen from the above results, the hydrogen fuel cell coolant provided by the present invention not only has excellent anti-freezing performance, can maintain fluidity in extremely low temperature environments, prevent damage to the fuel cell system due to icing, but also has high cooling efficiency, can quickly absorb and conduct a large amount of heat generated during the operation of the fuel cell, and ensure the stability of the battery operating temperature. In addition, the coolant also has excellent anti-corrosion and antibacterial properties, and can effectively resist the corrosion of metal components. More importantly, the coolant of the present invention has a low conductivity, significantly reducing the risk of electrolyte leakage or electrochemical corrosion. Moreover, the coolant has been optimized for compatibility with the membrane electrode materials of fuel cells, ensuring that while achieving high-efficiency heat dissipation, it will not have an adverse impact on the performance and lifespan of the membrane electrode, thus realizing high membrane electrode compatibility.

[0047] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A hydrogen fuel cell coolant, characterized in that: The hydrogen fuel cell coolant is composed of the following materials in parts by weight: 60-90 parts by weight of water, 5-20 parts by weight of carbon nano-modified propylene glycol ether, 0.5-5 parts by weight of 1-butyl-3-methylimidazole tetrafluoroborate, 3-12 parts by weight of polyethylene glycol, 0.5-5 parts by weight of organic borate, 0.1-3 parts by weight of polyacrylic acid, 0.1-0.8 parts by weight of quaternary ammonium salt, and 0.01-0.4 parts by weight of silver nanoparticles; The average volume diameter of the silver nanoparticles is 20-80 nm; The carbon nano-modified propylene glycol ether is a product prepared by a method comprising the following steps: The pretreated carbon nanoparticles are contacted and mixed with propylene glycol ether, and then subjected to ultrasonic treatment to obtain the carbon nano-modified propylene glycol ether; The pretreated carbon nanoparticles are products prepared by a method comprising the following steps: S1, soaking the carbon nanoparticles in an acid washing solution for 1-3 hours to obtain a mixture I; S2, heating the mixture I to 100-120° C. and reflux for 2-5 h, and washing with deionized water to obtain a mixture II; S3, subjecting the mixture II to a first reaction with a titanate coupling agent solution, and then calcining the mixture in an inert gas at 800-900° C. for 1-2 h to obtain the pretreated carbon nanoparticles.

2. The hydrogen fuel cell coolant according to claim 1, characterized in that: The weight ratio of the carbon nano-modified propylene glycol ether to the 1-butyl-3-methylimidazole tetrafluoroborate is 4-9:

1.

3. The hydrogen fuel cell coolant according to claim 1 or 2, characterized in that: The weight ratio of the quaternary ammonium salt to the silver nanoparticles is 2-8:

1.

4. The hydrogen fuel cell coolant according to claim 1 or 2, characterized in that: In step S1, the pickling solution is a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:

1.

5. A method for preparing a hydrogen fuel cell coolant, the method using the substance in the hydrogen fuel cell coolant according to any one of claims 1 to 4, characterized in that: The method includes: (1) mixing water and carbon nano-modified propylene glycol ether for a first contact to obtain a premixed solution I; (2) mixing the premixed solution I with 1-butyl-3-methylimidazolium tetrafluoroborate for a second contact to obtain a premixed solution II; (3) mixing polyethylene glycol, polyacrylic acid, and organic borate with the premixed solution II for a third contact to obtain a premixed solution III; (4) under ultrasonic conditions, the premixed solution III is mixed with the quaternary ammonium salt and the silver nanoparticles for a fourth contact, the pH is adjusted and then the impurities are removed by an ultrafine filtration device, and then the hydrogen fuel cell coolant is obtained after ion exchange; The dosage of each substance is: 60-90 parts by weight of water, 5-20 parts by weight of carbon nano-modified propylene glycol ether, 0.5-5 parts by weight of 1-butyl-3-methylimidazole tetrafluoroborate, 3-12 parts by weight of polyethylene glycol, 0.5-5 parts by weight of organic borate, 0.1-3 parts by weight of polyacrylic acid, 0.1-0.8 parts by weight of quaternary ammonium salt, and 0.01-0.4 parts by weight of silver nanoparticles.

6. The method according to claim 5, characterized in that In step (2), the first contact, the second contact, the third contact and the fourth contact are all carried out under stirring conditions, and each independently satisfies at least: a rotation speed of 400-600 rpm and a time of 20-50 min.

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