A fuel cell stack seal forming process

Abstract

The present application relates to the technical field of fuel cell, in particular to a fuel cell stack seal forming process. The present application is first to utilize the point glue assembly along the polar plate sealing groove to extrude the sealing glue, control the light source of the UV curing light source and the point glue assembly synchronous movement, ensure that the extruded sealing glue is irradiated by the UV light for the same time, and utilize the UV curing light source to perform one curing on the sealing glue; then utilize the UV curing light source to perform overall irradiation on the extruded sealing glue, perform secondary curing on the sealing glue, and complete the forming of the seal. The fuel cell stack seal forming process can increase the precision of the point glue size, provide better sealing effect and service life.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell stack sealing component molding process. Background Technology

[0002] Fuel cells are a type of new energy battery, possessing advantages such as low operating temperature, high specific power, and rapid start-up, and have become one of the hot research topics in the new energy field. The key components of a fuel cell are the membrane electrode assembly (MEA) and bipolar plates. The bipolar plates consist of a cathode plate and an anode plate with a flow field. The MEA contains a reaction zone and a supporting frame, placed between the anode and cathode plates. The reaction zone provides a platinum catalyst to support the electrochemical reaction, while the frame supports the reaction zone and isolates the anode and cathode plates to prevent short circuits.

[0003] Because fuel cells contain gaseous media such as hydrogen and air, as well as cooling media such as ethylene glycol, a seal is required between the MEA and the cathode and anode plates to prevent leakage of the media and cross-leakage between them. Poor sealing will directly lead to safety issues in the use of the fuel cell stack. However, as the requirements for power density and cost of fuel cell stacks become higher and higher, traditional sealing methods can no longer meet the requirements.

[0004] Patent CN110546179A discloses a photocurable resin composition, a fuel cell, and a sealing method using the same. The patent mentions a sealing gasket material for UV molding, which is a polyolefin-modified elastomer suitable for FIPG (Filmed In-Situ Gasket), CIPG (Cure-in-Situ Gasket), MIPG (Molded-in-Situ Gasket), and liquid injection molding. The CIPG process involves dispensing the gasket and then subjecting it to UV irradiation. Due to the starting and ending points of the dispensing path, the CIPG dispensing process typically lasts 30-120 seconds per piece. To ensure consistent glue height at both ends, the glue usually needs high thixotropy (non-flowing paste-like consistency). However, high thixotropy results in poor joint fusion, leading to excessive joint thickness, affecting the sealing effect, and causing premature joint failure.

[0005] To ensure the stability of the adhesive strip's shape before curing after dispensing, traditional adhesive sealants typically have a high thixotropic property. Otherwise, the dispensed strip would collapse due to gravity before curing. However, high thixotropy can affect the fusion of the adhesive strip joints, leading to deviations in joint height and width, thus impacting sealing performance and lifespan. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a molding process for fuel cell stack seals. This invention enables the sealant strip to maintain a good shape before curing without increasing the thixotropic properties of the sealant.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention provides a process for forming a fuel cell stack seal, comprising the following steps:

[0009] (S1) Use the dispensing assembly to extrude the sealant along the electrode sealing groove, and use a UV curing light source to cure it once;

[0010] (S2) After step (S1) is completed, the extruded sealant is irradiated with a UV curing light source to perform secondary curing and complete the molding of the sealant.

[0011] In one embodiment of the present invention, in step (S1), the UV curing light source moves synchronously with the dispensing assembly to ensure that the extruded sealant is irradiated by UV light for the same amount of time.

[0012] In one embodiment of the present invention, in step (S1), the distance between the lower surface of the dispensing assembly and the upper surface of the electrode sealing groove is 1 mm.

[0013] In one embodiment of the present invention, in step (S1), the sealant is a UV adhesive with a viscosity of 70,000-100,000 mPa·s.

[0014] In one embodiment of the present invention, the thixotropic index of the sealant is 2-4.

[0015] In one embodiment of the present invention, in step (S1), during the first curing process, the wavelength emitted by the UV curing light source is 365-405nm.

[0016] In one embodiment of the present invention, in step (S1), during the single curing process, the radiation intensity of the UV curing light source is ≥500mw / cm². 2 .

[0017] In one embodiment of the present invention, in step (S1), the curing time is 3-5 seconds.

[0018] In one embodiment of the present invention, in step (S2), during the secondary curing process, the wavelength emitted by the UV curing light source is 365-405nm.

[0019] In one embodiment of the present invention, in step (S2), the time for the secondary curing process is 20-30 seconds.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The fuel cell stack sealing component molding process of the present invention can increase the accuracy of the dispensing size, and provide better sealing effect and life.

[0022] (2) In the fuel cell stack sealing component molding process of the present invention, the adhesive has better wettability with the electrode sealing groove and the interface has better bonding and sealing effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the positional relationship between the dispensing assembly and the electrode plate;

[0024] Figure 2 This is a schematic diagram of the UV curing light source curing the sealant in one step.

[0025] Figure 3 This is a schematic diagram of the secondary curing of sealant by a UV curing light source;

[0026] The following are the labels in the diagram: 1. Dispensing assembly; 2. Sealant; 3. UV curing light source; 4. UV light source radiation area; 5. Electrode; 6. Electrode sealing groove. Detailed Implementation

[0027] This invention provides a process for forming a fuel cell stack seal, comprising the following steps:

[0028] (S1) Use the dispensing assembly to extrude the sealant along the electrode sealing groove, and use a UV curing light source to cure it once;

[0029] (S2) After step (S1) is completed, the extruded sealant is irradiated with a UV curing light source to perform secondary curing and complete the molding of the sealant.

[0030] In one embodiment of the present invention, in step (S1), the UV curing light source moves synchronously with the dispensing assembly to ensure that the extruded sealant is irradiated by UV light for the same amount of time.

[0031] In one embodiment of the present invention, in step (S1), the distance between the lower surface of the dispensing assembly and the upper surface of the electrode sealing groove is 1 mm.

[0032] In one embodiment of the present invention, in step (S1), the sealant is a UV adhesive with a viscosity of 70,000-100,000 mPa·s.

[0033] In one embodiment of the present invention, the thixotropic index of the sealant is 2-4.

[0034] In one embodiment of the present invention, in step (S1), during the first curing process, the wavelength emitted by the UV curing light source is 365-405nm.

[0035] In one embodiment of the present invention, in step (S1), during the single curing process, the radiation intensity of the UV curing light source is ≥500mw / cm². 2 .

[0036] In one embodiment of the present invention, in step (S1), the curing time is 3-5 seconds.

[0037] In one embodiment of the present invention, in step (S2), during the secondary curing process, the wavelength emitted by the UV curing light source is 365-405nm.

[0038] In one embodiment of the present invention, in step (S2), the time for the secondary curing process is 20-30 seconds.

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this embodiment, the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0043] Unless otherwise specified, all reagents used in the following embodiments are commercially available reagents, and all detection methods and techniques used are conventional detection methods and techniques in the art.

[0044] In the following examples and comparative examples, the UV curing light source emits wavelengths of 365-405 nm and has a radiation intensity ≥500 mw / cm². 2 .

[0045] Example 1

[0046] This embodiment provides a molding process for fuel cell stack seals.

[0047] A fuel cell stack sealing component molding process, which uses a UV molding device to mold the sealing component;

[0048] like Figure 1-3 As shown, the UV molding device includes a dispensing assembly 1 and a UV curing light source 3, which are respectively fixed to two independent robotic arms. During use, the assembly moves along the electrode sealing groove 6 on the electrode plate 5. The dispensing assembly 1 is filled with sealant 2 and is fixed above the electrode sealing groove 6. During local curing, the dispensing assembly 1 automatically dispenses sealant along the electrode sealing groove 6. The UV curing light source 3 moves synchronously with the dispensing assembly 1, so that the UV light source radiation area 4 always moves along the path of the dispensing assembly 1, ensuring that the extruded sealant 2 is in the UV light source radiation area 4 for the same amount of time, that is, irradiated by the UV curing light source 3 for the same amount of time. During overall curing, all locally cured sealant 2 is within the UV light source radiation area 4.

[0049] The sealing component molding process specifically includes the following steps:

[0050] (S1) The sealant 2 is extruded from the dispensing assembly 1 onto the electrode sealing groove 6. The distance between the lower surface of the dispensing assembly 1 and the upper surface of the electrode sealing groove 6 is 1mm, so that it is within the UV light source radiation area 4. Then, the dispensing assembly 1 and the UV curing light source 3 are controlled to move synchronously, and the time for the extruded sealant 2 to be irradiated by the UV curing light source 3 is kept for 3s to complete one curing.

[0051] (S2) After step (S1) is completed, the extruded sealant 2 is irradiated with UV curing light source 3 for 30 seconds to perform secondary curing of sealant 2 and complete the molding of the sealant.

[0052] Among them, sealant 2 is a UV adhesive with a thixotropic index of 3-4 and a viscosity of 80,000-100,000 mPa·s.

[0053] After the sealant is formed, the dispensing accuracy is within ±0.04mm, and the bonding strength between the sealant 2 and the electrode plate 5 is ≥4NM.

[0054] Example 2

[0055] This embodiment provides a molding process for fuel cell stack seals.

[0056] Except for step (S1), where the sealant is irradiated by the UV curing light source for 5 seconds, and step (S2), where the UV curing light source irradiates the extruded sealant for 20 seconds, and the sealant is a UV adhesive with a thixotropic index of 2-3 and a viscosity of 70,000-80,000 mPa·s, all other steps are the same as in Example 1.

[0057] After the sealant is formed, the dispensing accuracy is within ±0.02mm, and the bonding strength between the sealant and the electrode plate is ≥8NM.

[0058] Comparative Example 1

[0059] (S1) Extrude the sealant from the dispensing assembly onto the electrode sealing groove. The distance between the lower surface of the dispensing assembly and the upper surface of the electrode sealing groove is 1mm. Allow it to stand to complete one curing.

[0060] (S2) After step (S1) is completed, the extruded sealant is irradiated with a UV curing light source for 30 seconds to cure the sealant and complete the forming of the sealant.

[0061] The sealant has a thixotropic index > 5 and a viscosity > 150000 mPa·s.

[0062] After the sealant is formed, the dispensing accuracy is within ±0.05mm, and the bonding strength between the sealant and the electrode plate is <3NM.

[0063] Comparative Example 2

[0064] (S1) Extrude the sealant from the dispensing assembly onto the electrode sealing groove. The distance between the lower surface of the dispensing assembly and the upper surface of the electrode sealing groove is 1mm. Allow it to stand to complete one curing.

[0065] (S2) After step (S1) is completed, the extruded sealant is irradiated with a UV curing light source for 30 seconds to cure the sealant.

[0066] The sealant has a thixotropic index of 3-4 and a viscosity of 80,000-100,000 mPa·s.

[0067] The sealant collapsed before curing, making it impossible to cure the sealant.

[0068] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A molding process for a fuel cell stack sealing component, characterized in that, Includes the following steps: (S1) Use the dispensing assembly to extrude the sealant along the electrode sealing groove, and use a UV curing light source to cure it once; (S2) After step (S1) is completed, the extruded sealant is irradiated with a UV curing light source to perform secondary curing and complete the molding of the sealant. The UV curing light source moves synchronously with the dispensing assembly to ensure that the extruded sealant is irradiated with UV light for the same amount of time; the sealant is a UV adhesive with a viscosity of 70,000-100,000 mPa·s; the UV curing light source emits wavelengths of 365-405 nm and has a radiation intensity ≥500 mw / cm². 2 ; In step (S1), the distance between the lower surface of the dispensing assembly and the upper surface of the electrode sealing groove is 1 mm; The thixotropic index of the sealant is 2-4; In step (S1), the curing time is 3-5 seconds per cycle; In step (S2), the time for the secondary curing process is 20-30 seconds; After the sealant is formed, the dispensing accuracy is within ±0.02mm, and the bonding strength between the sealant and the electrode plate is ≥8NM.

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