Hydrogen fuel cell coolant

Abstract

The invention discloses a hydrogen fuel cell cooling liquid, which is prepared from the following components in parts by weight: 45 to 50 parts of propylene glycol, 0.01 to 0.2 part of organosilane, 0.01 to 0.1 part of organic corrosion inhibitor, 0.01 to 0.2 part of organic chelating agent, 0.0001 to 0.001 part of defoaming agent and the balance of pure water. The non-ionic additives such as the organic chelating agent, the organic corrosion inhibitor and the organosilane are used, so that the insulation characteristic of the cooling liquid is effectively improved, the conductivity of the cooling liquid is lower than 2 mu S / cm, and the safety of the hydrogen fuel cell is improved; through the synergistic effect of organosilane, the organic chelating agent and the organic corrosion inhibitor, the corrosion inhibition performance of the cooling liquid on metal is improved, and the cooling liquid has good compatibility with non-metal materials such as rubber.

Description

Technical Field

[0001] This invention relates to a coolant, and more particularly to a coolant for hydrogen fuel cells. Background Technology

[0002] With the rapid development of the new energy field, hydrogen fuel cells have been widely used in transportation, distributed power generation, and other fields due to their advantages such as high efficiency and environmental friendliness. During operation, hydrogen fuel cells generate a large amount of heat. If this heat cannot be dissipated effectively and in a timely manner, it can lead to excessively high internal temperatures, affecting the normal conduction of electrochemical reactions, reducing battery performance and lifespan, and even causing safety issues. Therefore, coolant plays a crucial role in the operation of hydrogen fuel cells.

[0003] Existing hydrogen fuel cell coolants have some shortcomings. Some coolants have a high ion concentration, resulting in high conductivity, which can lead to short circuits inside the hydrogen fuel cell, reducing power generation efficiency and output, affecting normal electrochemical reactions, and even damaging battery components in severe cases. Furthermore, while most commercially available coolants meet basic requirements for thermal conductivity and antifreeze, hydrogen fuel cell coolants that combine excellent metal corrosion inhibition properties with ultra-low conductivity are less commonly developed. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a high-performance hydrogen fuel cell coolant with ultra-low electrical conductivity, excellent thermal conductivity, antifreeze properties, and chemical stability.

[0005] Technical solution: The hydrogen fuel cell coolant of the present invention comprises the following components in parts by weight: 45-50 parts of propylene glycol, 0.01-0.2 parts of organosilane, 0.01-0.1 parts of organic corrosion inhibitor, 0.01-0.2 parts of organic chelating agent, 0.0001-0.001 parts of defoamer, and the balance being pure water.

[0006] The propylene glycol is 1,2-propanediol, and the propylene glycol is pharmaceutical grade propylene glycol.

[0007] The organosilane is at least one of γ-aminopropyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, and 3-mercaptopropylmethyldimethoxysilane.

[0008] The organic corrosion inhibitor is at least one of arginine stearamide, lysine bisamide, and tyrosine benzylamide.

[0009] The organic chelating agent is at least one of glutamic acid diacetic acid and iminodisuccinic acid.

[0010] The defoamer is a polyether-based defoamer.

[0011] The compound consists of organosilane, organic corrosion inhibitor, and organic chelating agent.

[0012] The weight ratio of the organosilane, organic corrosion inhibitor, and organic chelating agent in the coolant is 1.0–1.5:1.0:1.0–2.0.

[0013] The pure water is ultrapure water with a conductivity of <1μS / cm.

[0014] Preferably, the hydrogen fuel cell coolant has the following weight fraction composition: 50 parts propylene glycol, 0.015-0.15 parts organosilane, 0.01-0.1 parts organic corrosion inhibitor, 0.015-0.15 parts organic chelating agent, 0.0001 parts defoamer, and the balance being pure water.

[0015] Preferably, the weight ratio of the organosilane, organic corrosion inhibitor, and organic chelating agent in the coolant is 1.5:1.0:1.5.

[0016] Preferably, the polyether defoamer is present in a weight ratio of 0.0001 parts in the coolant.

[0017] The coolant exhibits insulation properties with a conductivity of <2.0 μS / cm.

[0018] The method for preparing the hydrogen fuel cell coolant according to the present invention specifically involves mixing the components according to the stated proportions.

[0019] The hydrogen fuel cell coolant of this invention combines organosilane, organic corrosion inhibitor, and organic chelating agent to improve the corrosion inhibition performance of the coolant on metals through the synergistic effect of the three.

[0020] The amino acid amide corrosion inhibitor used in this invention contains polar groups such as amino, amide, and carboxyl groups, giving the molecule a strong polarity. The nitrogen atoms on both the amide and amino groups contain lone pairs of electrons, which can act as active sites to form multiple coordination centers. These centers interact with atoms on the metal surface, forming coordinate bonds and adsorbing onto the metal surface to create a dense protective film, thus slowing down metal corrosion. Simultaneously, the oxygen atoms on the amide groups can assist in coordination, forming a "multi-point chelation" structure, further enhancing the corrosion inhibition effect on the metal.

[0021] The organosilanes used in this invention can form a siloxane protective film on a metal surface through hydrolysis and condensation reactions. The -Si-O-Si- network structure formed by the cross-linking of silane molecules serves as the bottom layer film, exhibiting high mechanical strength and erosion resistance, and resisting the physical penetration of corrosive media. The hydrophobic alkyl chains on the amino acid amide are interwoven within the silane network, reducing the surface energy of the amino acid amide protective film. Furthermore, the silanol groups of the organosilane form hydrogen bonds on the metal surface, strengthening the protective film and preventing the penetration of water and oxygen.

[0022] The organic chelating agent used in this invention has multiple coordinating atoms, which can form stable cyclic chelates with metal ions through "polydentate coordination," capturing metal corrosion product ions and anolyte active site ions, and inhibiting the dissolution reaction of the battery anode. Furthermore, the small molecular size of the organic chelating agent allows it to penetrate into the micropores of organosilane or amino acid amide protective films, binding to metal surface atoms through coordination bonds or hydrogen bonds, increasing film density. While promoting the film formation rate of the protective film on the metal surface, it significantly inhibits the generation of electrochemical corrosion on the metal surface through synergistic effects with organosilanes, preventing pitting corrosion. Simultaneously, the organic chelating agent also enhances the stability of organosilanes, making them less prone to precipitation and exhibiting good compatibility with various non-metallic materials such as rubber.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention uses nonionic additives such as organic chelating agents, organic corrosion inhibitors and organosilanes to effectively improve the insulation properties of the coolant, making its conductivity lower than 2μS / cm, thereby improving the safety of hydrogen fuel cells; (2) The present invention improves the corrosion inhibition performance of the coolant on metals through the synergistic effect of organosilanes, organic chelating agents and organic corrosion inhibitors, and has good compatibility with non-metallic materials such as rubber. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the embodiments. Unless otherwise stated, all reagents used are commercially available and are used directly without purification.

[0025] The metal corrosion inhibition performance test method of the hydrogen fuel cell coolant described in this invention refers to the glass corrosion in T / CAS 548—2021 "Hydrogen Fuel Cell Coolant". The test was conducted on copper, brass, 304 stainless steel, 316L stainless steel, 3A21 aluminum, 4043 aluminum, 5A05 aluminum, and 6063 aluminum at 80℃±2℃ for 336h±2h. The weight change of the metal sample before and after the test, the conductivity of the solution before the test, and the pH of the solution before the test were analyzed and recorded.

[0026] The non-metallic material compatibility test method for hydrogen fuel cell coolant described in this invention refers to the rubber compatibility test in T / CAS 548—2021 "Hydrogen Fuel Cell Coolant". EPDM rubber and silicone rubber are tested at 80℃ for 336h, and the hardness, volume, and mass of the rubber before and after the test are analyzed and recorded.

[0027] Example 1

[0028] The hydrogen fuel cell coolant in this embodiment is composed of the following components in parts by weight: 50 parts propylene glycol, 0.015 parts γ-aminopropyltriethoxysilane, 0.01 parts arginine stearamide, 0.015 parts glutamic acid diacetic acid, 0.0001 parts polyether defoamer, and the balance being ultrapure water.

[0029] Examples 2-10:

[0030] The coolants for each embodiment were prepared similarly to those in Example 1, except that the types of amino acid amide corrosion inhibitors, organosilanes, and organic chelating agents were adjusted. The component changes are shown in Table 1.

[0031] Table 1. Formulation Table of Examples (Parts by Weight)

[0032]

[0033]

[0034] In Table 1, " / " indicates that the symbol does not exist.

[0035] Comparative Examples 1-10

[0036] Coolants for each comparative example were prepared in a similar manner to those in Example 1, except that the coolant components were different, and the component variations are shown in Table 2.

[0037] Table 2 Comparative proportions (parts by weight)

[0038]

[0039] To verify the effectiveness of the metal corrosion inhibition performance of the present invention, the corrosion methods of glassware in T / CAS 548—2021 "Coolant for Hydrogen Fuel Cells" were used to test Examples 1 to 10 and Comparative Examples 1 to 10. The test results are shown in Tables 3 and 4, respectively.

[0040] Table 3. Test results of glassware in the examples.

[0041]

[0042]

[0043] Table 4. Test results of comparative glassware

[0044]

[0045] In the table, "+" indicates an increase in the weight loss of the test piece, and "-" indicates a decrease in the weight loss of the test piece.

[0046] Referring to Table 3, the coolants in Examples 1-10 exhibit excellent corrosion resistance to various metals, including copper, brass, 304 stainless steel, 316L stainless steel, 3A21 aluminum, 4043 aluminum, 5A05 aluminum, and 6063 aluminum. Among them, Example 3 showed the best overall performance, exhibiting lower electrical conductivity, indicating better insulation properties. Furthermore, it resulted in the least weight loss in the aluminum alloy after the glassware corrosion experiment, demonstrating a better corrosion inhibition effect on aluminum alloys. Although the electrical conductivity of the coolants in Examples 1 and 2 was lower than that of Example 3, their corrosion inhibition effects on aluminum alloys were relatively poor. Therefore, tyrosine benzylamide was the preferred organic corrosion inhibitor.

[0047] The experimental results of Example 4 show that when iminodisuccinic acid is used as an organic chelating agent, the metal weight loss increases significantly, indicating that its chelating effect with metal is not as good as that of glutamic acid diacetic acid. Therefore, glutamic acid diacetic acid is the preferred organic chelating agent. The experimental results of Examples 5 and 6 show that the use of γ-aminopropyltriethoxysilane can significantly improve the corrosion inhibition performance of the coolant on metals and reduce the conductivity of the coolant. Therefore, γ-aminopropyltriethoxysilane is the preferred organosilane.

[0048] In Example 7, increasing the organosilane content in the coolant did not significantly improve metal corrosion inhibition performance, but it significantly increased conductivity, indicating that a higher organosilane content is not necessarily better. In Examples 8-10, increasing the content of organic corrosion inhibitors and organic chelating agents, respectively, did not significantly change the metal corrosion inhibition effect, but the conductivity of the coolant increased significantly, indicating that a higher content of organic corrosion inhibitors and organic chelating agents is not always better. In summary, considering both coolant cost and performance, the weight ratio of organosilane, organic corrosion inhibitor, and organic chelating agent in the coolant of Example 3 is preferred.

[0049] Referring to Table 4, the coolant in Comparative Example 1 was a propylene glycol aqueous solution (blank group). Although it is an insulating liquid, its metal corrosion inhibition performance was extremely poor, failing to provide any protective effect on the metal. The coolant in Comparative Example 2 did not contain organosilanes, resulting in poor corrosion inhibition of steel and aluminum alloys, and its low pH made it prone to acidification. The coolant in Comparative Example 3 did not contain any organic corrosion inhibitors, leading to poor corrosion inhibition of copper, steel, and aluminum alloys. The coolant in Comparative Example 4 did not contain any organic chelating agents, resulting in localized pitting corrosion on the metal surface and poor corrosion inhibition of aluminum alloys. The coolants in Comparative Examples 5–7 significantly increased the content of single additives, leading not only to increased coolant conductivity, affecting its insulating properties, but also increasing costs. The coolants in Comparative Examples 8–10 contained only single additives, resulting in poor metal corrosion inhibition performance. In summary, the synergistic effect of the combination of organosilanes, organic corrosion inhibitors, and organic chelating agents improved the corrosion inhibition effect of the coolant on metals.

[0050] According to the rubber compatibility test in T / CAS 548—2021 "Hydrogen Fuel Cell Coolant", the preferred embodiment 3 was tested, and the test results are as follows:

[0051] Table 5. Rubber compatibility test results in Example 3

[0052]

[0053] Referring to Table 5, after a long-term high-temperature rubber compatibility test, the hardness, volume, and tensile properties of the EPDM rubber and silicone rubber immersed in the coolant of Example 3 did not change significantly, indicating that the present invention has excellent rubber compatibility.

Claims

1. A hydrogen fuel cell coolant, characterized in that, The product comprises the following components in parts by weight: 45-50 parts propylene glycol, 0.01-0.2 parts organosilane, 0.01-0.1 parts organic corrosion inhibitor, 0.01-0.2 parts organic chelating agent, 0.0001-0.001 parts defoamer, and the balance being pure water.

2. The hydrogen fuel cell coolant according to claim 1, characterized in that, The propylene glycol is 1,2-propanediol.

3. The hydrogen fuel cell coolant according to claim 1, characterized in that, The organosilane is at least one of γ-aminopropyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, and 3-mercaptopropylmethyldimethoxysilane.

4. The hydrogen fuel cell coolant according to claim 1, characterized in that, The organic corrosion inhibitor is at least one of arginine stearamide, lysine bisamide, and tyrosine benzylamide.

5. The hydrogen fuel cell coolant according to claim 1, characterized in that, The organic chelating agent is at least one of glutamic acid diacetic acid and iminodisuccinic acid.

6. The hydrogen fuel cell coolant according to claim 1, characterized in that, The defoamer is a polyether-based defoamer.

7. The hydrogen fuel cell coolant according to claim 1, characterized in that, The compound consists of organosilane, organic corrosion inhibitor, and organic chelating agent.

8. The hydrogen fuel cell coolant according to claim 7, characterized in that, The weight ratio of the organosilane, organic corrosion inhibitor, and organic chelating agent in the coolant is 1.0–1.5:1.0:1.0–2.

0.

9. The hydrogen fuel cell coolant according to claim 1, characterized in that, The components are composed of the following weight fractions: 50 parts propylene glycol, 0.015-0.15 parts organosilane, 0.01-0.1 parts organic corrosion inhibitor, 0.015-0.15 parts organic chelating agent, 0.0001 parts defoamer, and the balance being pure water.

10. The hydrogen fuel cell coolant according to claim 1, characterized in that, The conductivity of the coolant is <2.0 μS / cm.

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