A self-repairing fuel cell bipolar plate and preparation method thereof

Abstract

The present application discloses a self-repairing fuel cell bipolar plate and a preparation method thereof. The bipolar plate is composed of the following raw materials in parts by mass: 50 to 80 parts of graphite worms; 10 to 20 parts of graphite flakes; 10 to 20 parts of conductive polyaniline; 10 to 20 parts of lignin / glass-like polymer intelligent composite materials; and 1 to 10 parts of reinforcing materials. The self-repairing fuel cell bipolar plate of the present application can simultaneously possess the advantages of metal bipolar plates and graphite bipolar plates. While having excellent electrical conductivity, thermal conductivity, and corrosion resistance, it also has a bending strength close to that of metal bipolar plates. In addition, due to its self-repairing performance to a certain extent, its service life is better than that of metal bipolar plates and graphite-based bipolar plates currently on the market.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a self-repairing fuel cell bipolar plate and a preparation method thereof. Background Art

[0002] Hydrogen fuel cells are clean, efficient, and long-life power generation devices that have great advantages in terms of efficiency, safety, reliability, flexibility, cleanliness, and operational performance, and have broad application prospects. The bipolar plate is called the "skeleton" of hydrogen fuel cells. Its main function is to provide a gas flow channel to prevent hydrogen and oxygen in the battery gas chamber from communicating with each other, and to establish a current path between the positive and negative poles in series.

[0003] The mainstream bipolar plates at present are metal bipolar plates and graphite-based bipolar plates. Metal plate stacks have advantages in strength, but metal plates have poor corrosion resistance (which means limited life). Graphite-based bipolar plates are better in electrical conductivity, thermal conductivity, service life, corrosion resistance, etc., but have poor bending strength and other aspects. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a self-repairing fuel cell bipolar plate and a preparation method thereof, so as to improve the service life and bending strength of the fuel cell bipolar plate, and at the same time have the self-repairing ability for slight deformation or cracking caused by impact or solution immersion.

[0005] The present application provides a self-repairing fuel cell bipolar plate, which is composed of the following raw materials in parts by weight:

[0006] 50 to 80 parts of graphite worms;

[0007] 10 to 20 parts of graphite flakes;

[0008] 10 to 20 parts of conductive polyaniline;

[0009] 10 to 20 parts of lignin / glass-like polymer intelligent composite material;

[0010] 1 to 10 parts of reinforcing material.

[0011] Preferably, the size of the graphite worms is 200-500 mesh. Graphite worms are expanded graphite that expands instantly at high temperatures, changing from flake to worm-like, with a loose and porous structure, an enlarged surface area, increased surface energy, and enhanced ability to adsorb flake graphite; the worm-like graphite can also be self-interlocking. Graphite worms not only retain the original properties of natural graphite, but also have properties such as softness, resilience, self-adhesion, impermeability, adsorption and low density, as well as pressure resistance, high pressure resistance, low temperature resistance, corrosion resistance, radiation resistance, shock resistance, aging resistance and distortion resistance.

[0012] Preferably, the volume size of the graphite flakes is 500-1500 mesh. The graphite flakes are used to fill the gaps between the graphite worms. At the same time, the graphite worms are loose and porous, and have strong adsorption capacity for flake graphite, so that the two can be better dispersed together, so that the bipolar plate can maintain flexibility, pressure resistance and anti-aging while further improving the conductivity and surface density of the device.

[0013] Preferably, the conductive polyaniline is an α-zirconium phosphate (α-ZrP) / polyaniline (PANi) composite material. The conductive polyaniline is a superconducting polyaniline. Compared with general conductive polyaniline, due to the strong interaction between α-ZrP and PANi, the transmission of free electrons is accelerated, so that the conductivity is enhanced, so that the conductivity of PANi prepared after doping with α-ZrP is significantly higher than that of undoped PANi, and the conductive polyaniline also has certain reinforcement properties.

[0014] Preferably, the lignin / glass-like polymer smart composite material is a biomass-based polyhydroxyurethane glass-like polymer synthesized by a highly efficient polyaddition reaction between bihexacyclic carbonate (BCC) and biomass diamine (Priamine 1074).

[0015] The lignin / glass-like polymer smart composite material is selected from the biomass-based polyhydroxy polyurethane glass-like polymer prepared by Professor Zhao Wei's research group of the School of Light Industry Science and Engineering of Shaanxi University of Science and Technology in the "Green and Efficient Preparation of Lignin / Glass-like Polymer Smart Composite Materials". This polymer smart composite material has good self-healing properties and strength, can be used as a reinforcing material for the system, and use its self-healing properties to enhance the service life of the bipolar plate.

[0016] Furthermore, the reinforcing material is a high Tg thermosetting plastic. Preferably, the high Tg thermosetting plastic includes one or more of polyvinylidene fluoride (PVDF), phenolic resin (PF) and melamine-formaldehyde resin (MF). The above reinforcing materials have the properties of heat resistance, high hardness, mechanical properties, good electrical properties, water resistance, solvent resistance and chemical resistance. At the same time, the addition of reinforcing materials can further improve the bending strength and mechanical properties of the bipolar plate.

[0017] The self-repairing fuel cell bipolar plate of the present application can simultaneously possess the advantages of metal bipolar plates and graphite bipolar plates. While having excellent electrical conductivity, thermal conductivity, and corrosion resistance, it also has a bending strength close to that of metal bipolar plates. At the same time, the bipolar plate of the present application has self-repairing properties for slight deformation or cracking caused by impact or solution immersion, making its service life better than the metal bipolar plates and graphite-based bipolar plates currently on the market.

[0018] The present application also provides a method for preparing a self-repairing fuel cell bipolar plate, comprising the following steps:

[0019] Step 1, weighing raw materials according to mass fractions, and mixing graphite worms, graphite flakes, conductive polyaniline, lignin / glass-like polymer intelligent composite materials and reinforcing materials into a mixed powder;

[0020] Step 2, adding the mixed powder obtained in step 1 to a graphite plate pressing mold, placing the graphite plate pressing mold into a roller pressing device for roller pressing, and the roller pressure is 1800kg to 2500kg;

[0021] Step 3, placing the graphite plate roll-formed in step 2 into an oven at 200° C. to 250° C. for 2 h to 4 h, until the graphite plate is completely solidified, thereby obtaining a self-repairing fuel cell bipolar plate.

[0022] Furthermore, the step 1 specifically includes:

[0023] Step 11, adding graphite worms and graphite flakes into a dry powder spraying device for spraying and mixing;

[0024] Step 12, adding the mixed powder obtained in step 11 and the conductive polyaniline into a dry powder spraying device for spray mixing;

[0025] Step 13, adding the mixed powder obtained in step 12 and the lignin / glass-like polymer intelligent composite material to a dry powder spraying device for spraying and mixing;

[0026] Step 14, adding the mixed powder obtained in step 13 and the reinforcing material into the dry powder spraying equipment for spray mixing.

[0027] Preferably, the roller pressure is 2000 kg and the oven temperature is 230°C.

[0028] The preparation method of the present application is simple to operate and does not require special equipment. It is different from the conventional preparation process of fuel cell bipolar plates. It abandons the conventional mechanical blending method (mechanical blending will definitely destroy the structure of the expanded graphite and affect the final bipolar plate performance). It adopts the dry powder spraying equipment in the coating field to disperse and mix the powders by spraying, so that the internal structure of the expanded graphite can be completely maintained, so that the final performance of the bipolar plate after pressing is optimized to meet the requirements of industrial production. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0030] As used herein, the term "prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0031] When amount, concentration or other value or parameter is expressed as range, preferred range or a series of upper preferred value and lower preferred value limit range, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1 to 5", described range should be interpreted as including range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0032] In addition, the indefinite articles "a" and "an" before the elements or components of the present invention have no restrictions on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the number is obviously intended to be in the singular form.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0034] Example 1

[0035] A self-repairing fuel cell bipolar plate, comprising the following raw materials in parts by weight:

[0036] 50 parts of graphite worms; 10 parts of graphite flakes; 10 parts of conductive polyaniline; 10 parts of lignin / glass-like polymer intelligent composite material; 1 part of polyvinylidene fluoride.

[0037] A method for preparing a self-repairing fuel cell bipolar plate comprises the following steps:

[0038] Step 1, weigh the raw materials according to the mass fraction, add the graphite worms and graphite flakes into the dry powder spraying equipment for spray mixing; then add the mixed powder and conductive polyaniline into the dry powder spraying equipment for spray mixing; then add the mixed powder and lignin / glass-like polymer intelligent composite material into the dry powder spraying equipment for spray mixing; finally, add the mixed powder and reinforcing material into the dry powder spraying equipment for spray mixing.

[0039] Step 2, adding the mixed powder obtained in step 1 to a graphite plate pressing mold, placing the graphite plate pressing mold into a roller pressing device for roller pressing, and the roller pressure is 2000 kg;

[0040] Step 3, placing the graphite plate roll-formed in step 2 into an oven at 230° C. for more than 2 hours until the graphite plate is completely solidified to obtain a self-repairing fuel cell bipolar plate.

[0041] Example 2

[0042] A self-repairing fuel cell bipolar plate, comprising the following raw materials in parts by weight:

[0043] 80 parts of graphite worms; 10 parts of graphite flakes; 10 parts of conductive polyaniline; 10 parts of lignin / glass-like polymer intelligent composite material; 1 part of phenolic resin. The preparation method of the self-repairing fuel cell bipolar plate is the same as that of Example 1.

[0044] Example 3

[0045] A self-repairing fuel cell bipolar plate, comprising the following raw materials in parts by weight:

[0046] 50 parts of graphite worms; 20 parts of graphite flakes; 20 parts of conductive polyaniline; 20 parts of lignin / glass-like polymer intelligent composite material; 10 parts of melamine-formaldehyde resin. The preparation method of the self-repairing fuel cell bipolar plate is the same as that of Example 1.

[0047] Example 4

[0048] A self-repairing fuel cell bipolar plate, comprising the following raw materials in parts by weight:

[0049] 80 parts of graphite worms; 20 parts of graphite flakes; 20 parts of conductive polyaniline; 20 parts of lignin / glass-like polymer intelligent composite material; 10 parts of a mixture of polyvinylidene fluoride, phenolic resin and melamine-formaldehyde resin in a mass ratio of 1:1:1. The preparation method of the self-repairing fuel cell bipolar plate is the same as that of Example 1.

[0050] Comparative Example 1

[0051] The lignin / glass-like polymer intelligent composite material is not contained, and the other parts are the same as those in Example 4.

[0052] Comparative Example 2

[0053] Conductive carbon fiber is used instead of conductive polyaniline, and the rest is the same as in Example 4.

[0054] Comparative Example 3

[0055] No reinforcing material is contained, and the rest is the same as in Example 4.

[0056] Comparative Example 4

[0057] Ordinary graphite is used to replace the graphite worms and graphite flakes, and the rest is the same as in Example 4.

[0058] Bipolar plate characteristics test

[0059] The bipolar plates prepared by Test Examples 1 to 4 and Comparative Examples 1 to 4 were tested for their properties according to GB / T 20042.6-2024. The test results are shown in Table 1 below.

[0060] Table 1 Bipolar plate characteristic test results of Examples 1 to 4 and Comparative Examples 1 to 4

[0061]

[0062] As shown in Table 1, the test results of the bipolar plate characteristics prepared in Examples 1 to 4 all meet the bipolar plate characteristic indicators of the U.S. Department of Energy (DOE) in 2020 and 2025. Compared with Comparative Example 1, Example 4 containing lignin / glass-like polymer intelligent composite material has better material properties than Comparative Example 1, wherein the life of Example 4 is significantly improved, and has better bending strength; Compared with Comparative Example 2, Example 4 using conductive polyaniline has better material properties than Comparative Example 2 using conductive carbon fiber, wherein the bending strength is significantly improved, and has better mass power density; Compared with Comparative Example 3, Example 4 containing reinforcement material has better material properties than Comparative Example 3, wherein the bending strength is significantly improved, and has a longer life; Compared with Comparative Example 4, Example 4 using graphite worms and graphite flakes has better material properties than Comparative Example 4, wherein the life of Example 3 is significantly improved. By comparing Example 4 with Comparative Examples 1 to 4, it can be seen that the use of graphite worms, graphite flakes, conductive polyaniline, lignin / glass-like polymer intelligent composite materials and reinforcing materials as raw materials for preparing bipolar plates in the present application can achieve a synergistic effect, thereby optimizing the life and bending strength of the bipolar plates.

[0063] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A self-repairing fuel cell bipolar plate, characterized in that: It is composed of the following raw materials in parts by weight: 50 to 80 parts of graphite worms; 10 to 20 parts of graphite flakes; 10 to 20 parts of conductive polyaniline; 10 to 20 parts of lignin / glass-like polymer intelligent composite material; 1 to 10 parts of reinforcing material; The lignin / glass-like polymer intelligent composite material is a biomass-based polyhydroxy polyurethane glass-like polymer synthesized by a high-efficiency addition polymerization reaction between a di-hexagonal carbonate and a biomass diamine Priamine 1074; The reinforcing material includes one or more of polyvinylidene fluoride, phenolic resin and melamine-formaldehyde resin.

2. The self-repairing fuel cell bipolar plate according to claim 1, characterized in that: The size of the graphite worms is 200-500 meshes.

3. The self-repairing fuel cell bipolar plate according to claim 1, characterized in that: The volume size of the graphite flakes is 500-1500 meshes.

4. The self-repairing fuel cell bipolar plate according to claim 1, characterized in that: The conductive polyaniline is an alpha-zirconium phosphate / polyaniline composite material.

5. A method for preparing a self-repairing fuel cell bipolar plate according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, weighing raw materials according to mass fractions, and mixing graphite worms, graphite flakes, conductive polyaniline, lignin / glass-like polymer intelligent composite materials and reinforcing materials into a mixed powder; Step 2, adding the mixed powder obtained in step 1 to a graphite plate pressing mold, placing the graphite plate pressing mold into a roller pressing device for roller pressing, and the roller pressure is 1800kg to 2500kg; Step 3, placing the graphite plate roll-formed in step 2 into an oven at 200° C. to 250° C. for 2 h to 4 h, until the graphite plate is completely solidified, thereby obtaining a self-repairing fuel cell bipolar plate.

6. The method for preparing a self-repairing fuel cell bipolar plate according to claim 5, characterized in that: The step 1 specifically includes: Step 11, adding graphite worms and graphite flakes into a dry powder spraying device for spraying and mixing; Step 12, adding the mixed powder obtained in step 11 and the conductive polyaniline into a dry powder spraying device for spraying and mixing; Step 13, adding the mixed powder obtained in step 12 and the lignin / glass-like polymer intelligent composite material to a dry powder spraying device for spraying and mixing; Step 14, adding the mixed powder obtained in step 13 and the reinforcing material into the dry powder spraying equipment for spray mixing.

7. The method for preparing a self-repairing fuel cell bipolar plate according to claim 5, characterized in that: The roller pressure was 2000 kg and the oven temperature was 230°C.

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