A fluorozirconate brazing seam compatible hydrogen fuel cell coolant and method of making

Abstract

The application discloses a kind of fluoroaluminate brazing seam compatibility hydrogen fuel cell coolant and preparation method thereof, each raw material is formed according to weight parts: alcohol compound 100 parts, bone glue 0.1-1 parts, azole compound 0.4-1 parts, ester compound 0.01-0.2 parts, 2,4,6-tri [(p-carboxyl phenyl) amino]-1,3,5-triazine 0.3-2 parts, silicate 0.02-0.3 parts and deionized water 5-200 parts.The hydrogen fuel cell coolant of the application has low conductivity and excellent potassium fluoroaluminate weld compatibility, and can be applied to hydrogen fuel cell engine temperature control system.

Description

TECHNICAL FIELD

[0001] The application relates to a hydrogen fuel cell coolant with brazing agent weld compatibility of fluoroaluminate, in particular to a liquid with the functions of fluoroaluminate brazing weld compatibility and multi-metal corrosion resistance for an aluminum radiator temperature control system adopting fluoroaluminate as a brazing agent, and belongs to the chemical industry field. BACKGROUND

[0002] The aluminum radiator is widely applied to engine, new energy vehicle, hydrogen fuel cell and other temperature control systems due to light weight, excellent heat conductivity and other advantages. The most important link of the aluminum radiator is brazing forming. The most commonly used corrosion-free brazing agent for aluminum and aluminum alloy is a fluoroaluminate brazing agent which is composed of potassium fluoroaluminate, rubidium fluoroaluminate or cesium fluoroaluminate, has the characteristics of no corrosion and no need to clean the residue after welding, destroys the oxide film of the aluminum alloy during the welding process, makes the molten filler material wet with the base material, maintains and protects the integrity of the film after welding, and reduces the corrosion of the welded joint. The article "Influence of potassium fluoroaluminate welding aid on the corrosion behavior of automobile radiator fins" (Corrosion Science and Protection Technology, Vol. 22, No. 3, May 2010) points out that the potassium fluoroaluminate welding aid improves the anodic activity of aluminum or aluminum alloy materials and reduces the cathodic activity, easily forms electrochemical corrosion with the aluminum material of the radiator, and greatly shortens the service life of the aluminum radiator. In the hydrogen fuel cell temperature control system, the aggravation of the electrochemical corrosion directly increases the conductivity of the hydrogen fuel cell coolant due to the anions and cathions of the corrosion products, reduces the service life of the deionization tank, directly affects the normal use of the hydrogen fuel cell, and increases the maintenance cost and downtime risk.

[0003] As the coolant of the fuel cell cooling system, the conductivity of the coolant is crucial to the normal operation of the system. During the circulation of the hydrogen fuel cell coolant, the conductivity will continuously rise, which is mainly caused by the organic impurities generated by the oxidation of ethylene glycol and the metal ions generated by the metal corrosion in the temperature control system. The engine coolant has good metal corrosion resistance to various metals, but the conductivity is generally between 1000 us / cm and 4000 us / cm, which is far more than the requirement of not more than 5 us / cm of the hydrogen fuel cell coolant, and therefore cannot be directly applied to the hydrogen fuel cell cooling system. For example:

[0004] Patent CN01131412.5 discloses an engine coolant made of 1000 parts ethylene glycol, 2-8 parts sebacic acid, 2-5 parts terephthalic acid, 1-4 parts toluene-triazole, 5-25 parts p-tert-butylbenzoic acid, 1-12 parts octanoic acid, 1-4 parts succinic acid, and 0.1-0.2 parts defoamer. This coolant is specifically designed for engine cooling systems. Although it has good metal corrosion resistance, its conductivity is greater than 2000 μs / cm, making it unsuitable for use in hydrogen fuel cell cooling systems.

[0005] Chinese patent CN109148915A discloses a fuel cell coolant whose main components are ethylene glycol, triethanolamine, alkyl diethanolamide, triphosphate, triazole compounds, defoamer and deionized water. It has antifreeze and anti-corrosion functions. However, the use of triethanolamine in this coolant will increase the conductivity itself. In addition, it cannot solve the corrosion of fluoroaluminate brazing flux welds.

[0006] US Patent 8187763B discloses a coolant composition for a fuel cell unit, which contains at least one fatty alcohol having unsaturated bonds in each molecule having 2 to 20 carbon atoms, solving the oxidation problem of ethylene glycol in the coolant, thereby ensuring that the coolant composition maintains the conductivity of the coolant at 10 μs / cm or lower. However, this coolant does not have a corrosion-preventing effect and cannot inhibit the precipitation of ions from metal components.

[0007] US Patent 20040086757 discloses a fuel cell and a fuel cell coolant composition, which consists of deionized water, a freezing point inhibitor, a polymer ion inhibitor, and an organic corrosion inhibitor, ensuring the low conductivity of the coolant. However, polymer ion inhibitors still cannot solve the problem of metal corrosion, and as ion removal agents, they are prone to sedimentation and clogging of pipes.

[0008] Chinese patent CN113429945A discloses a fuel cell coolant and its preparation method, which is composed of alcohol compounds, bone glue, azole compounds, ester compounds and deionized water. The coolant has excellent low conductivity and excellent corrosion resistance to brass, steel and aluminum, but it has poor protection against fluoroaluminate brazing flux welds and cannot inhibit the ion precipitation of fluoroaluminate brazing flux welds.

[0009] Therefore, based on the corrosion protection requirements of fluoroaluminate brazing flux welds, it is necessary to develop a hydrogen fuel cell coolant to suppress the formation of ions from fluoroaluminate brazing flux deposited in the welds of components such as intercoolers and radiators. Summary of the Invention

[0010] In view of the deficiencies of the prior art, the present application aims to provide a hydrogen fuel cell coolant with low conductivity and excellent brazing seam compatibility of fluoroaluminate brazing flux.

[0011] In order to achieve the purpose, the present application adopts the following technical solutions:

[0012] The present application discloses a hydrogen fuel cell coolant with excellent brazing seam compatibility of fluoroaluminate, which is characterized in that the components are composed of 100 parts of an alcohol compound, 0.1-1 parts of bone glue, 0.4-1 parts of an azole compound, 0.01-0.2 parts of an ester compound, 0.3-2 parts of 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine, 0.02-0.3 parts of silicate, and 5-200 parts of deionized water.

[0013] Further, the alcohol compound is one or more of ethylene glycol, propylene glycol, and glycerol, preferably ethylene glycol.

[0014] Further, the silicate is sodium silicate or potassium silicate, preferably sodium silicate.

[0015] Further, the azole compound is one or more of methyl benzotriazole, benzotriazole, 2-mercaptobenzothiazole (MBT), and 2-amino-5-mercapto-1,3,4-thiadiazole (AMT).

[0016] Further, the ester compound is selected from triethanolamine borate or a modified nitrogen-containing borate derivative.

[0017] Further, the deionized water has a resistivity of not less than 15 MΩ·cm.

[0018] The conductivity of the fuel cell coolant obtained by the present application is 0.5 μS / cm-2 μS / cm.

[0019] Based on a large number of experimental researches and test experiments, the present application selects the alcohol compound and the azole compound, determines the optimal selection of silicate, ester compound, and 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine, so as to produce a synergistic effect, i.e., to improve the metal corrosion resistance under the condition of low conductivity, especially the compatibility of the brazing seam of the aluminum alloy fluoroaluminate brazing flux.

[0020] In order to further reduce the conductivity of the hydrogen fuel cell coolant and improve the compatibility of the brazing seam of the aluminum alloy fluoroaluminate brazing flux, the present application explores the amount of each component in the above fuel cell coolant and determines a more optimal ratio, which is as follows:

[0021] Preferably, the fuel cell coolant is composed of 100 parts of alcohol compound, 0.2-0.8 parts of bone glue, 0.5-0.9 parts of azole compound, 0.05-0.18 parts of ester compound, 0.4-1.8 parts of 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine, 0.1-0.2 parts of silicate and 5-200 parts of deionized water.

[0022] More preferably, the fuel cell coolant is composed of 100 parts of alcohol compound, 0.2-0.5 parts of bone glue, 0.6-0.8 parts of azole compound, 0.1-0.15 parts of ester compound, 0.6-1.2 parts of 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine, 0.15-0.18 parts of silicate and 5-200 parts of deionized water.

[0023] Further preferably, the fuel cell coolant is composed of 100 parts of alcohol compound, 0.2-0.5 parts of bone glue, 0.6-0.8 parts of azole compound, 0.1-0.15 parts of ester compound, 0.6-1.2 parts of 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine, 0.15-0.18 parts of silicate and 5-200 parts of deionized water, and the mass ratio of silicate, ester compound and 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine is 0.2:0.1:(1.2-1.5).

[0024] The present application also provides a preparation method of the above-mentioned fluoroaluminate brazing seam compatible hydrogen fuel cell coolant, comprising the following steps:

[0025] 1) adding silicate and azole compound into deionized water, stirring until dissolved, slowly adding bone glue, and stirring to obtain a uniform solution;

[0026] 2) mixing and stirring the solution obtained in step 1) with alcohol compound, then adding ester compound and 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine and stirring uniformly to obtain a completely dissolved solution with an electrical conductivity of not more than 1500 μS / cm;

[0027] 3) removing solid impurities in the solution obtained in step 2) through an ultra-filtration device, then removing metal and non-metal anions and cations in the solution through a spectrapure mixed bed semiconductor grade DI resin until the electrical conductivity is 0.5 μS / cm-2 μS / cm, to obtain the fluoroaluminate brazing seam compatible hydrogen fuel cell coolant.

[0028] The hydrogen fuel cell coolant of this invention is formulated using ionic and nonionic corrosion inhibitors, alcohol compounds, and deionized water. Based on the principle of corrosion inhibition and film formation, the ionic and nonionic corrosion inhibitors dissolved in the alcohol compounds and deionized water form adsorption and precipitation films at the weld joints of aluminum alloy fluoroaluminate brazing flux. This prevents corrosion caused by metal polarization due to brazing, blocks the increase in conductivity caused by ion release due to corrosion, and extends the service life of brazed components such as aluminum alloy heat sinks. Based on the principle of hard and soft acids and bases, hard and soft acids are selected to protect the cast aluminum used in the cooling system. In particular, the synergistic effect of silicates, borate esters, and 2,4,6-tris[(p-carboxyphenyl)amino]-1,3,5-triazine further significantly improves the protection of the aluminum alloy brazed weld joints. The excellent anti-corrosion performance of the metal inhibits the release of metal ions into the coolant, thereby enhancing the retention of low conductivity.

[0029] The fuel cell coolant of this invention possesses properties such as low electrical conductivity and excellent weld compatibility with fluoroaluminate brazing flux. Compared to existing technologies, the beneficial effects of the technical solution adopted in this invention are reflected in:

[0030] 1. Compared with high-conductivity engine coolant technology, the coolant of the present invention has excellent low-conductivity performance, ensuring the normal operation of hydrogen fuel cell engines;

[0031] 2. Compared with other low conductivity coolant technologies, the coolant of the present invention has excellent low conductivity retention, which extends the service life of the coolant and the service life of the deion tank in the temperature control system of the hydrogen fuel cell engine.

[0032] 3. The coolant of this invention has excellent weld compatibility with fluoroaluminate brazing flux, effectively preventing corrosion of aluminum alloy radiators and other components, and effectively extending the service life of aluminum alloy radiators and other components. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0034] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0035] The preparation method described in the following examples is strictly configured according to the order of addition. The ultrafiltration is carried out using a 1μm ultrafiltration device, and the ion exchange resin used is Spectrapure mixed bed semiconductor grade DI resin.

[0036] Example 1

[0037] The present example provides a fuel cell coolant, the preparation method of which is as follows:

[0038] Sodium silicate 0.2 g, methyl benzotriazole 4 g were added to deionized water 1000 g, stirred and dissolved uniformly, bone glue 1 g was slowly added, and stirred to obtain a uniform solution; the obtained solution was mixed and stirred with ethylene glycol 1000 g, then triethanolamine borate 0.1 g, 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine 3 g were added and stirred uniformly to obtain a completely dissolved solution, and the conductivity thereof was 513 μS / cm. After removing the solid impurities in the obtained solution by an ultra-filtration device, the metal and non-metal anions and cations in the solution were removed by a spectrapure mixed bed semiconductor grade DI resin, and a hydrogen fuel cell coolant with a conductivity of 0.5 μS / cm was obtained.

[0039] Example 2

[0040] The present example provides a fuel cell coolant, the preparation method of which is as follows:

[0041] Sodium silicate 3 g, methyl benzotriazole 10 g were added to deionized water 1000 g, stirred and dissolved uniformly, bone glue 10 g was slowly added, and stirred to obtain a uniform solution; the obtained solution was mixed and stirred with ethylene glycol 1000 g, then triethanolamine borate 2 g, 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine 20 g were added and stirred uniformly to obtain a completely dissolved solution, and the conductivity thereof was 1325 μS / cm. After removing the solid impurities in the obtained solution by an ultra-filtration device, the metal and non-metal anions and cations in the solution were removed by a spectrapure mixed bed semiconductor grade DI resin, and a hydrogen fuel cell coolant with a conductivity of 1.0 μS / cm was obtained.

[0042] Example 3

[0043] The present example provides a fuel cell coolant, the preparation method of which is as follows:

[0044] Sodium silicate 1.5 g, methyl benzotriazole 7 g were added to deionized water 1000 g, stirred and dissolved uniformly, bone glue 5 g was slowly added, and stirred to obtain a uniform solution; the obtained solution was mixed and stirred with ethylene glycol 1000 g, then triethanolamine borate 1 g, 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine 10 g were added and stirred uniformly to obtain a completely dissolved solution, and the conductivity thereof was 1056 μS / cm.

[0045] After removing the solid impurities in the obtained solution through an ultra-filtration device, the metal and non-metal anions and cations in the solution are removed through a spectrapure mixed-bed semiconductor-grade DI resin, so that a hydrogen fuel cell coolant with a conductivity of 0.8 μS / cm is obtained.

[0046] Example 4

[0047] The present example provides a fuel cell coolant, and the preparation method is as follows:

[0048] Sodium silicate 1.8 g, methyl benzotriazole 8 g to deionized water 1000 g, stirring uniform dissolution, slowly add bone glue 2 g, stirring to get a uniform solution; the obtained solution and ethylene glycol 1000 g are mixed and stirred, then triethanolamine borate 1.2 g, 2,4,6-tris [(p-carboxyl phenyl) amino]-1,3,5-triazine 8 g are stirred uniformly to obtain a completely dissolved solution, and the conductivity thereof is 1010 μS / cm. After removing the solid impurities in the obtained solution through an ultra-filtration device, the metal and non-metal anions and cations in the solution are removed through a spectrapure mixed-bed semiconductor-grade DI resin, so that a hydrogen fuel cell coolant with a conductivity of 0.6 μS / cm is obtained.

[0049] Example 5

[0050] The present example provides a fuel cell coolant, and the preparation method is as follows:

[0051] Sodium silicate 2 g, methyl benzotriazole 7 g to deionized water 1000 g, stirring uniform dissolution, slowly add bone glue 5 g, stirring to get a uniform solution; the obtained solution and ethylene glycol 1000 g are mixed and stirred, then triethanolamine borate 1 g, 2,4,6-tris [(p-carboxyl phenyl) amino]-1,3,5-triazine 12 g are stirred uniformly to obtain a completely dissolved solution, and the conductivity thereof is 1102 μS / cm. After removing the solid impurities in the obtained solution through an ultra-filtration device, the metal and non-metal anions and cations in the solution are removed through a spectrapure mixed-bed semiconductor-grade DI resin, so that a hydrogen fuel cell coolant with a conductivity of 1.2 μS / cm is obtained.

[0052] Example 6

[0053] The present example provides a fuel cell coolant, and the preparation method is as follows:

[0054] Sodium silicate 2g, methyl benzotriazole 7g to deionized water 1000g, stirring uniform dissolution, slowly add bone glue 5g, stirring to get a uniform solution; the solution obtained with ethylene glycol 1000g mixing stirring, then add triethanolamine borate 1g, 2,4,6-tri[(p-carboxyphenyl) amino]-1,3,5-triazine 15g stirring uniform, get completely dissolved solution, its conductivity is 1218 μs / cm. After the ultrafiltration device to remove the solid impurities in the solution, then by spectrapure mixed bed semiconductor grade DI resin to remove the metal and non-metallic anions and cations in the solution, the conductivity of 1.0 μs / cm of hydrogen fuel cell coolant is obtained.

[0055] Example 7

[0056] The present embodiment provides a kind of fuel cell coolant, its preparation method is as follows:

[0057] Sodium silicate 1g, methyl benzotriazole 7g to deionized water 1000g, stirring uniform dissolution, slowly add bone glue 5g, stirring to get a uniform solution; the solution obtained with ethylene glycol 1000g mixing stirring, then add triethanolamine borate 0.5g, 2,4,6-tri[(p-carboxyphenyl) amino]-1,3,5-triazine 7g stirring uniform, get completely dissolved solution, its conductivity is 698 μs / cm After the ultrafiltration device to remove the solid impurities in the solution, then by spectrapure mixed bed semiconductor grade DI resin to remove the metal and non-metallic anions and cations in the solution, the conductivity of 1.0 μs / cm of hydrogen fuel cell coolant is obtained.

[0058] Comparative Example 1

[0059] The present comparative example provides a kind of heat transfer medium, its composition includes ethylene glycol 1000kg, deionized water 1000kg, its conductivity is 0.8 μs / cm.

[0060] Comparative Example 2

[0061] The present comparative example is provided by patent CN01131412.5 embodiment 1 a kind of engine coolant, its composition includes by weight parts: ethylene glycol 1000kg, sebacic acid 2kg, terephthalic acid 5kg, methyl benzotriazole 1kg, p-tert-butyl benzoic acid 25kg, octanoic acid 1kg, succinic acid kg, defoaming agent 0.1kg, deionized water 1000kg, after mixing stirring uniform, obtain coolant, its conductivity is 3200 μs / cm.

[0062] Comparative Example 3

[0063] A hydrogen fuel cell coolant currently sold on the market is a well-known German brand, such as BASF Glysantin FCG20-00 / 50.

[0064] Comparative Example 4

[0065] A hydrogen fuel cell coolant currently sold on the market is a well-known American brand, such as Dynalene LC.

[0066] Comparative Example 5

[0067] This comparative example is the coolant provided in Example 4 of patent CN113429945A.

[0068] The fuel cell coolants prepared in Examples 1-7 and the coolants prepared in Comparative Examples 1-5 were subjected to performance testing. The solutions of the examples and comparative examples were tested according to the test method of Appendix A in T / CAS 48-2021, and a standard test piece of 3003 aluminum brazed with fluoroaluminate brazing flux was added, with a weld width of 1 mm, located in the middle of the test piece, parallel to the length of the test piece, to test the conductivity of the hydrogen fuel cell coolant sample and the metal corrosion of the test piece sample. The specific test results are shown in Table 1. The standard test piece of 3003 aluminum brazed with fluoroaluminate brazing flux corrosion test represents the compatibility of the fluoroaluminate brazing seam.

[0069] Table 1 Performance test results of fuel cell coolants of Examples 1-7 and Comparative Examples 1-5

[0070]

[0071]

[0072] In summary, the fuel cell coolant of the present application has excellent low conductivity performance, low conductivity retention, and fluoroaluminate brazing seam compatibility, thereby ensuring the normal operation of the hydrogen fuel cell engine, significantly reducing the precipitation of ions, prolonging the service life of the coolant and the deionization tank, and effectively prolonging the service life of aluminum alloy radiators and other components.

[0073] It should be noted that the above examples are only used to explain the present application and do not constitute any limitation on the present application. The present application has been described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. Modifications can be made to the present application within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications with the same function.

Claims

1. A fluoroaluminate brazing seam compatible hydrogen fuel cell coolant, characterized by, The raw materials are composed of 100 parts of alcohol compound, 0.1-1 parts of bone glue, 0.4-1 parts of azole compound, 0.01-0.2 parts of ester compound, 0.3-2 parts of 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine, 0.02-0.3 parts of silicate and 5-200 parts of deionized water by weight; The silicate is sodium silicate or potassium silicate; the ester compound is triethanolamine borate or modified nitrogen-containing borate derivative; the mass ratio of silicate, ester compound and 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine is 0.2:0.1: (1.2-1.5).

2. The fluoroaluminate brazing seam compatible hydrogen fuel cell coolant of claim 1, wherein: The alcohol compound is one or more of ethylene glycol, propylene glycol and glycerol.

3. The fluoroaluminate brazing seam compatible hydrogen fuel cell coolant of claim 1, wherein, The azole compound is one or more of methyl benzotriazole, benzotriazole, 2-mercaptobenzothiazole and 2-amino-5-mercapto-1,3,4-thiadiazole.

4. The fluoroaluminate brazing seam compatible hydrogen fuel cell coolant of claim 1, wherein, The deionized water has a resistivity of 15 MΩ·cm or more.

5. The fluoroaluminate brazing seam compatible hydrogen fuel cell coolant of any of claims 1-4, wherein: The hydrogen fuel cell coolant has a conductivity of 0.5 μS / cm-2 μS / cm.

6. A method for producing the hydrogen fuel cell coolant according to any one of claims 1 to 5, characterized by, The method comprises the following steps: 1) adding silicate and azole compound into deionized water, stirring until dissolved, slowly adding bone glue, and stirring to obtain a uniform solution; 2) mixing and stirring the solution obtained in step 1) with alcohol compound, then adding ester compound and 2,4,6-tris[(p-carboxyl phenyl) amino]-1,3,5-triazine and stirring uniformly to obtain a completely dissolved solution with a conductivity of not more than 1500 μS / cm; 3) removing solid impurities in the solution obtained in step 2) through an ultra-filtration device, then removing metal and non-metal anions and cations in the solution through spectrapure mixed bed semiconductor grade DI resin until the conductivity is 0.5 μS / cm-2 μS / cm, to obtain the hydrogen fuel cell coolant with brazing seam compatibility.

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