CN114395376A

CN114395376A - Fuel cell cooling liquid suitable for low-temperature environment and preparation method thereof

Info

Publication number: CN114395376A
Application number: CN202210044231.7A
Authority: CN
Inventors: 晁华; 张龙; 胡曼; 蔡逸飞
Original assignee: Xiangyang Daan Automobile Test Center Co Ltd
Current assignee: Xiangyang Daan Automobile Test Center Co Ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2022-04-26
Anticipated expiration: 2042-01-14
Also published as: CN114395376B

Abstract

The application relates to a fuel cell coolant suitable for a low-temperature environment and a preparation method thereof, relating to the technical field of coolants, wherein the fuel cell coolant comprises the following components in percentage by mass: 45-75% of ultrapure water, 20-50% of ethylene glycol, 0.5-2% of corrosion inhibitor, 0.5-1% of stabilizer, 0.1-0.5% of antioxidant and 0.05-1.5% of defoaming agent. The preparation method comprises the following steps: dividing the ultrapure water into four parts, and respectively marking as ultrapure water A, ultrapure water B, ultrapure water C and ultrapure water D; dissolving a stabilizer and an antioxidant in ultrapure water A to obtain a solution A; dissolving a corrosion inhibitor in the ultrapure water B to obtain a solution B; dissolving the defoaming agent in the ultrapure water C, and uniformly stirring to obtain a solution C; adding the solution A into ethylene glycol, uniformly stirring, adding the solution B, and continuously stirring to obtain a solution D; and adding ultrapure water D into the solution D, uniformly stirring, and then adding the solution C until the solution D is uniformly dispersed without foam to obtain the fuel cell cooling liquid.

Description

Fuel cell cooling liquid suitable for low-temperature environment and preparation method thereof

Technical Field

The application relates to the technical field of cooling liquid, in particular to fuel cell cooling liquid suitable for a low-temperature environment and a preparation method thereof.

Background

The fuel cell cooling system is different from the traditional engine cooling system, the cooling liquid needs to flow through a bipolar plate cooling flow channel of a fuel cell stack and then flows to an air cooling device through a pipeline, the special use environment of the cooling liquid has the requirement of extremely low conductivity on the cooling liquid, along with the requirement on the power density of the fuel cell in recent years, the bipolar plate material is gradually developed into a thinner and more compact metal material, the air cooling device is generally made of the metal material, and even if the components are subjected to passivation and corrosion prevention treatment, the common cooling liquid in the long-time oxidation reduction environment cannot meet the safety requirement of the fuel cell.

Ultrapure water is generally adopted as a cooling medium in a normal-temperature environment, but is not suitable for a low-temperature environment, and in addition, the ultrapure water can adsorb cations released by technical components in the using process to cause conductivity increase, influence on the performance of the fuel cell and even cause safety accidents.

In the related art, a coolant for a low conductivity fuel cell system is disclosed, the coolant comprising the following components: uracil, ultrapure water, ethylene glycol and antifoam, organic corrosion inhibitors and lactitol also being present. The defoaming agent is polyether defoaming agent, and the polyether defoaming agent is any one of GP type glycerol polyether, GPE type polyoxyethylene (polyoxypropylene) ether or PPG type polypropylene glycol. The introduction of the lactitol is found to solve the defect of poor stability of the cooling liquid by adding the lactitol into the fuel cell cooling liquid, so that the prepared cooling liquid can stably run under the condition of lower conductivity, and floccules do not appear in the use process.

However, although the above-mentioned solutions add corrosion inhibitors and stabilizers to alleviate corrosion of metal parts and dissolution of metal ions in the coolant, the following problems still remain:

the ethylene glycol is mixed with impurities such as aldehydes, ketones and acids in the production process, the acids are in contact with metals for a long time or increase the corrosion risk in a high-temperature environment, and the cooling liquid is in an oxidation-reduction environment, wherein the mixed aldehydes and ketones are easily oxidized into the acids, so that the corrosion of metal parts is accelerated, metal ions are dissolved into the cooling liquid, the conductivity is increased, and the service life of the cooling liquid is directly influenced.

Disclosure of Invention

The embodiment of the application provides a fuel cell cooling liquid suitable for a low-temperature environment and a preparation method thereof, and aims to solve the problems that in the related art, when the cooling liquid is in an oxidation-reduction environment, aldehyde and ketone substances mixed in ethylene glycol are easily oxidized into acid substances, corrosion of metal parts is accelerated, and metal ions are dissolved in the cooling liquid, so that the conductivity is increased, and the service life of the cooling liquid is directly influenced.

In a first aspect, a fuel cell coolant suitable for use in a low temperature environment is provided, the fuel cell coolant comprising, by mass percent: 45-75% of ultrapure water, 20-50% of ethylene glycol, 0.5-2% of corrosion inhibitor, 0.5-1% of stabilizer, 0.1-0.5% of antioxidant and 0.05-1.5% of defoaming agent.

In some embodiments, the corrosion inhibitor is sodium organosilicate.

In some embodiments, the corrosion inhibitor is at least one of sodium metasilicate, sodium methyl silicate, sodium ethyl silicate, and polyether organic sodium disilicate.

In some embodiments, the stabilizer is 2-mercaptoethanol or epoxysuccinic acid.

In some embodiments, the antioxidant is at least one of antioxidant 330 and tocopherol.

In some embodiments, the defoamer is at least one of a polyether defoamer, a silicon polyether defoamer, and a silicone defoamer.

In some embodiments, the fuel cell coolant includes: 57.3 percent of ultrapure water, 40 percent of ethylene glycol, 2 percent of corrosion inhibitor, 0.5 percent of stabilizer, 0.1 percent of antioxidant and 0.1 percent of defoaming agent.

In some embodiments, the corrosion inhibitor comprises sodium metasilicate and sodium ethyl silicate, wherein the mass ratio of the sodium metasilicate to the fuel cell coolant is 0.5 and 1.5, respectively.

In a second aspect, there is provided a method for preparing the fuel cell coolant suitable for low temperature environment, which includes the following steps:

dividing the ultrapure water into four parts, and respectively marking as ultrapure water A, ultrapure water B, ultrapure water C and ultrapure water D;

dissolving the stabilizer and the antioxidant in the ultrapure water A to obtain a solution A;

dissolving the corrosion inhibitor in the ultrapure water B to obtain a solution B;

dissolving the defoaming agent in the ultrapure water C, and uniformly stirring to obtain a solution C;

adding the solution A into the ethylene glycol, uniformly stirring, adding the solution B, and continuously stirring to obtain a solution D;

and adding the ultrapure water D into the solution D, uniformly stirring, and then adding the solution C until the solution D is uniformly dispersed without foam to obtain the fuel cell cooling liquid.

In some embodiments, the ultrapure water A, the ultrapure water B, the ultrapure water C and the ultrapure water D have equal mass fractions.

The beneficial effect that technical scheme that this application provided brought includes: the fuel cell coolant suitable for the low-temperature environment provided by the embodiment of the application is applicable to the environment temperature as follows: the cooling liquid is not condensed at minus 40 ℃ to minus 80 ℃; and at 60-70 ℃, the electric conductivity of the cooling liquid does not exceed 4 mu S/m after a durability test for 2500 hours, and the cooling liquid has good stability. Therefore, the cooling liquid of the embodiment of the application can not be condensed in a low-temperature environment, and can keep low conductivity in a high-temperature environment for long-time operation, so that the fuel cell can be safely and efficiently operated at a low temperature, and the service life of the cooling liquid is prolonged.

The embodiment of the application provides a fuel cell cooling liquid suitable for a low-temperature environment and a preparation method thereof, and the fuel cell cooling liquid is prepared by mixing analytically pure ethylene glycol and ultrapure water, so that the introduction of impurities is greatly reduced, and the risk of conductivity rise caused by external impurities is reduced. Meanwhile, the organosilicate corrosion inhibitor adopted in the embodiment of the application has extremely low electrolysis degree and low addition amount, has no influence on the conductivity of the electrolyte of the fuel cell, and has the main effects that in the use process, the organosilicate corrosion inhibitor can be slowly attached to a metal corrosion part to form a compact silicon-metal film on the surface of metal, the extremely thin silicon-metal film basically has no influence on heat dissipation, the film has extremely good corrosion resistance, the further corrosion of the metal can be prevented, and the influence of metal components in a cooling loop on the conductivity of the cooling liquid can be greatly reduced. Furthermore; even if once metal is corroded and metal ions are released into the cooling liquid, the 2-mercaptoethanol or the epoxy succinic acid in the embodiment of the application can capture the metal ions in the cooling liquid to form a chelate, so that the conductivity of the cooling liquid is reduced, and meanwhile, the 2-mercaptoethanol or the epoxy succinic acid can be adsorbed on the metal ions on the metal surface, so that the metal ions are prevented from being dissolved into the cooling liquid, the ion concentration in the cooling liquid is reduced, and the service life of the cooling liquid is prolonged. Finally, the matrix of the cooling liquid is glycol, and in order to prevent the glycol from being oxidized into aldehyde or acid substances in the redox environment, an antioxidant is added in the embodiment of the application, and the antioxidant 330 or tocopherol can play a role in preventing the glycol from being oxidized and deteriorated.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described, and it is obvious that the described embodiments are a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The embodiment of the application provides a fuel cell coolant suitable for low temperature environment, and its suitable ambient temperature is: the cooling liquid is not condensed at minus 40 ℃ to minus 80 ℃; and at 60-70 ℃, the electric conductivity of the cooling liquid does not exceed 4 mu S/m after a durability test for 2500 hours, and the cooling liquid has good stability. Therefore, the cooling liquid of the embodiment of the application can not be condensed in a low-temperature environment, and can keep low conductivity in a high-temperature environment for long-time operation, so that the fuel cell can be safely and efficiently operated at a low temperature, and the service life of the cooling liquid is prolonged.

According to the mass percentage, the fuel cell cooling liquid suitable for the low-temperature environment comprises 45-75% of ultrapure water, 20-50% of ethylene glycol, 0.5-2% of corrosion inhibitor, 0.5-1% of stabilizer, 0.1-0.5% of antioxidant and 0.05-1.5% of defoaming agent.

The corrosion inhibitor provided by the embodiment of the application is organic sodium silicate.

The corrosion inhibitor provided by the embodiment of the application is at least one of sodium metasilicate, sodium methyl silicate, sodium ethyl silicate and polyether organic sodium disilicate.

The stabilizer provided by the embodiment of the application is 2-mercaptoethanol or epoxy succinic acid.

The antioxidant provided by the embodiment of the application is at least one of antioxidant 330 and tocopherol.

The defoaming agent provided by the embodiment of the application is at least one of a polyether defoaming agent, a silicon polyether defoaming agent and an organic silicon defoaming agent.

In the fuel cell cooling liquid suitable for the low-temperature environment provided by the embodiment of the application, analytically pure ethylene glycol and ultrapure water are mixed, so that the introduction of impurities is greatly reduced, and the risk of conductivity increase caused by external impurities is reduced. Meanwhile, the organosilicate corrosion inhibitor adopted in the embodiment of the application has extremely low electrolysis degree and low addition amount, has no influence on the conductivity of the electrolyte of the fuel cell, and has the main effects that in the use process, the organosilicate corrosion inhibitor can be slowly attached to a metal corrosion part to form a compact silicon-metal film on the surface of metal, the extremely thin silicon-metal film basically has no influence on heat dissipation, the film has extremely good corrosion resistance, the further corrosion of the metal can be prevented, and the influence of metal components in a cooling loop on the conductivity of the cooling liquid can be greatly reduced. Furthermore; even if once metal is corroded and metal ions are released into the cooling liquid, the 2-mercaptoethanol or the epoxy succinic acid in the embodiment of the application can capture the metal ions in the cooling liquid to form a chelate, so that the conductivity of the cooling liquid is reduced, and meanwhile, the 2-mercaptoethanol or the epoxy succinic acid can be adsorbed on the metal ions on the metal surface, so that the metal ions are prevented from being dissolved into the cooling liquid, the ion concentration in the cooling liquid is reduced, and the service life of the cooling liquid is prolonged. Finally, the matrix of the cooling liquid is glycol, and in order to prevent the glycol from being oxidized into aldehyde or acid substances in the redox environment, an antioxidant is added in the embodiment of the application, and the antioxidant 330 or tocopherol can play a role in preventing the glycol from being oxidized and deteriorated.

The inventor conducts a large number of experiments to select the formula of the cooling liquid, determine the parts by weight of ultrapure water, ethylene glycol, a corrosion inhibitor, a stabilizer, an antioxidant and a defoaming agent, and select examples 1-16 to analyze and explain.

Examples 1 to 6

In examples 1 to 6, the coolant comprises 40% of ultrapure water, 57.3% of ethylene glycol, 2% of corrosion inhibitor, 0.5% of stabilizer, 0.1% of antioxidant, and 0.1% of defoaming agent, wherein the corrosion inhibitor is sodium metasilicate and sodium ethyl silicate, the stabilizer is epoxysuccinic acid, the antioxidant is antioxidant 330, and the defoaming agent is a silicon polyether defoaming agent.

The preparation method of the fuel cell coolant suitable for the low-temperature environment in the embodiments 1 to 6 includes the following steps:

s1: dividing the ultrapure water into four equal parts, and respectively marking as ultrapure water A, ultrapure water B, ultrapure water C and ultrapure water D;

s2: dissolving a stabilizer and an antioxidant in ultrapure water A at 60 ℃ to obtain solution A;

s3: dissolving a corrosion inhibitor in ultrapure water B at normal temperature to obtain solution B;

s4: dissolving the defoaming agent in ultrapure water C at normal temperature, and uniformly stirring to obtain solution C;

s5: adding the solution A into ethylene glycol, uniformly stirring, adding the solution B, and continuously stirring to obtain a solution D;

s6: and adding the ultrapure water D at the normal temperature into the solution D, uniformly stirring, and then adding the solution C until the solution D is uniformly dispersed without foam to obtain the fuel cell cooling liquid.

The compounding ratios of the components in examples 1 to 6 are shown in Table 1.

TABLE 1 Experimental formulas of examples 1-6

Several comparative examples were selected below for analysis, see comparative examples 1-4 below.

The main difference between the comparative examples 1-2 and the example 3 is that the content of the stabilizer is different, the stabilizer in the comparative example 1 is epoxy succinic acid, and the content is 0.3%; the stabilizer in comparative example 2 was epoxy succinic acid, and the content was 0.7%.

The main difference between comparative examples 3-4 and example 3 is that the antioxidant content is different, and the antioxidants of comparative examples 3-4 are all antioxidant 330, and the antioxidant content is 0.2% and 0.5%, respectively.

The preparation method of the fuel cell coolant suitable for the low-temperature environment in comparative examples 1 to 4 includes the steps of:

s6: adding normal-temperature ultrapure water D into the solution D, uniformly stirring, adding the solution C until the solution D is uniformly dispersed without foam, and obtaining the fuel cell cooling liquid

The compounding ratios of the components in comparative examples 1 to 4 are shown in Table 2.

TABLE 2 Experimental formulation tables for comparative examples 1-4

The cooling liquids prepared in examples 1 to 6 and comparative examples 1 to 4 were subjected to a durability test to obtain a curve of the change of the conductivity of the cooling liquid with time. The test results are shown in Table 3.

The endurance test was performed in accordance with GB 2454-2009 standard.

TABLE 3 test results

From the test results in table 3, it can be seen that example 3 of the present application is the best formulation, wherein the coolant comprises 40% ultrapure water, 57.3% ethylene glycol, 2% corrosion inhibitor, 0.5% stabilizer, 0.1% antioxidant, and 0.1% defoamer, wherein the corrosion inhibitors are sodium metasilicate and sodium ethyl silicate, the stabilizer is epoxy succinic acid, the antioxidant is antioxidant 330, the defoamer is silicon polyether defoamer, and the sodium metasilicate and sodium ethyl silicate are respectively contained in an amount of 0.5% and 1.5%.

From examples 1-6, it can be seen that when the total corrosion inhibitor content is 2%, the best effect cannot be achieved by using sodium metasilicate or ethyl sodium silicate alone, because sodium metasilicate has a good corrosion inhibition effect, promotes softening of water, and adjusts and stabilizes ph, but the duration of action is short, and the corrosion inhibition effect is reduced after long-term operation. But the corrosion inhibition effect of sodium ethyl silicate is not as good as that of sodium metasilicate, but the action time is long, so that the corrosion inhibition effect is complemented. The smaller the content of sodium metasilicate, the higher the conductivity of the coolant because sodium metasilicate has a good corrosion inhibition effect at the initial stage of use, and if the content is low, the metal in the initial environment releases metal ions at the initial stage, thus resulting in an increase in the conductivity thereof.

From example 3 and comparative examples 1 and 2, it is understood that when the stabilizer is epoxysuccinic acid, the conductivity of the coolant decreases and then increases as the content of the stabilizer increases, because the epoxysuccinic acid belongs to the stabilizer, and when a small amount of the epoxysuccinic acid is added, the stabilizer acts, the stabilizing effect is gradually enhanced as the addition amount increases, and when the addition amount reaches a certain amount, partial hydrolysis is generated in an aqueous solution and a high-temperature environment, hydrogen ions are released, and the conductivity is increased.

From example 3 and comparative examples 3 and 4, it can be seen that when the antioxidant 330 is selected as the antioxidant, the higher the content is, the higher the conductivity of the cooling liquid is, because the antioxidant 330 is hindered phenol antioxidant, and the addition amount thereof exceeds the limit value, the antioxidant can prevent alcohols from being oxidized, and when the addition amount exceeds the limit value, the antioxidant can be hydrolyzed in a small amount in a high-temperature environment in an aqueous solution system to generate hydrogen ions, so that the conductivity is increased.

In the description of the present application, these terms are used merely to facilitate the description of the application and to simplify the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered limiting of the application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fuel cell coolant suitable for use in a low temperature environment, the fuel cell coolant comprising, in mass percent: 45-75% of ultrapure water, 20-50% of ethylene glycol, 0.5-2% of corrosion inhibitor, 0.5-1% of stabilizer, 0.1-0.5% of antioxidant and 0.05-1.5% of defoaming agent.

2. The fuel cell coolant suitable for use in a low temperature environment according to claim 1, wherein the corrosion inhibitor is sodium organosilicate.

3. The fuel cell coolant suitable for use in a low temperature environment according to claim 2, wherein the corrosion inhibitor is at least one of sodium metasilicate, sodium methyl silicate, sodium ethyl silicate, and polyether organic sodium disilicate.

4. The fuel cell coolant suitable for use in a low-temperature environment according to claim 1, wherein the stabilizer is 2-mercaptoethanol or epoxysuccinic acid.

5. The fuel cell coolant suitable for use in a low temperature environment of claim 1, wherein the antioxidant is at least one of antioxidant 330 and tocopherol.

6. The fuel cell coolant suitable for use in a low-temperature environment according to claim 1, wherein the defoaming agent is at least one of a polyether defoaming agent, a silicon polyether defoaming agent, and a silicone defoaming agent.

7. The fuel cell coolant adapted for use in a low temperature environment according to claim 1, comprising: 57.3 percent of ultrapure water, 40 percent of ethylene glycol, 2 percent of corrosion inhibitor, 0.5 percent of stabilizer, 0.1 percent of antioxidant and 0.1 percent of defoaming agent.

8. The fuel cell coolant suitable for use in a low temperature environment according to claim 7, wherein the corrosion inhibitor comprises sodium metasilicate and sodium ethyl silicate, and the mass ratio of the sodium metasilicate to the sodium ethyl silicate to the fuel cell coolant is 0.5 and 1.5, respectively.

9. A method for preparing a fuel cell coolant suitable for use in a low temperature environment according to claim 1, comprising the steps of:

10. The method for producing a fuel cell coolant suitable for a low-temperature environment according to claim 9, wherein the ultrapure water a, the ultrapure water B, the ultrapure water C and the ultrapure water D are equal in mass fraction average.