A single cell packaging structure and a method for manufacturing the same

Abstract

The application discloses a single cell packaging structure and a preparation method thereof, relates to the technical field of single cells, and the membrane electrode comprises a proton exchange membrane and catalyst layers located on two sides of the proton exchange membrane. The catalyst layer on one side is bonded with a hot melt adhesive layer of a single-sided adhesive frame, and the catalyst layer on the other side is overlapped on a double-sided adhesive frame. After the hot melt adhesive layer of the single-sided adhesive frame bonds the catalyst layer, the excess part is bonded with the double-sided adhesive frame. The upper and lower sides of the double-sided hot melt adhesive frame are respectively provided with polar plates. The membrane electrode and the two polar plates form a gas diffusion layer. The obtained single cell has good sealing effect and is not prone to reaction medium leakage.

Description

Technical Field

[0001] This invention relates to the field of single-cell technology, and more specifically to a single-cell packaging structure and its preparation method. Background Technology

[0002] A fuel cell is a power generation device that directly converts the chemical energy present in fuel and oxidant into electrical energy. Fuel cells have advantages such as zero emissions, no vibration or noise, good load response, and high reliability. Fuel cells can generally be classified into alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, and proton exchange membrane fuel cells. Among them, proton exchange membrane fuel cells have high energy conversion efficiency, can start quickly at room temperature, have no water loss due to electrolysis, and have a long lifespan. They have developed rapidly in recent years and are receiving increasing attention.

[0003] In fuel cells, the sealing performance of a single cell directly affects its operating efficiency and lifespan. Traditional encapsulation processes often employ monolithic sealing or single-layer adhesive sealing, which suffers from problems such as uneven sealing, easy contamination of active areas by the adhesive layer, and insufficient resistance to operating conditions. For example, monolithic encapsulation is prone to adhesive overflow, which can cover the active areas of the membrane electrode assembly (MEA) and reduce electrochemical reaction efficiency; single-layer adhesive is prone to aging and failure under extreme conditions such as high temperature and strong acid, resulting in leakage of the reaction medium. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to provide a single-cell packaging structure that has a good sealing effect and is not prone to leakage of the reaction medium, in order to address the shortcomings of the existing technology.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A single-cell encapsulation structure includes a membrane electrode, which comprises a proton exchange membrane and catalyst layers located on both sides of the proton exchange membrane. One side of the catalyst layer is bonded to a hot melt adhesive layer of a single-sided adhesive frame, and the other side of the catalyst layer overlaps on a double-sided adhesive frame. The portion of the hot melt adhesive layer of the single-sided adhesive frame that extends beyond the catalyst layer is bonded to the double-sided adhesive frame. Electrode plates are respectively provided on the upper and lower sides of the double-sided hot melt adhesive frame, and a gas diffusion layer is provided between the membrane electrode and the two electrode plates.

[0007] Preferably, the single-sided adhesive frame is made of polyphenylene sulfide as the substrate, coated with hot melt adhesive I on one side and then die-cut to remove the active area. The hot melt adhesive I is composed of acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent in a weight ratio of 100:5-10:0.5-3:50-100, wherein the diluent is a mixed solution of xylene and ethyl acetate.

[0008] Preferably, the method for preparing the single-sided adhesive frame is as follows:

[0009] S01, Preparation of hot melt adhesive liquid

[0010] Acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent are mixed in proportion, stirred at room temperature and 500-1000 r / min for 20-40 min, and the mixture is stirred evenly to obtain hot melt adhesive liquid.

[0011] S02, Preparation of single-sided adhesive frame

[0012] The hot melt adhesive liquid obtained in step S01 is filtered, coated onto a polyphenylene sulfide substrate with a thickness of 9-25μm using a doctor blade coater or CED coater, dried completely, and then a release film is attached and the substrate is rolled up and cured to obtain a single-sided adhesive frame.

[0013] Preferably, the double-sided adhesive frame is made of polyphenylene ether or polyphenylene sulfide as the base material, coated with hot melt adhesive II on both sides and then die-cut to remove the active area. The hot melt adhesive II is composed of high melting point polyolefin resin, epoxidized thermoplastic elastomer, modifier and antioxidant in a weight ratio of 100:10-30:0.5-5:0.5-3.

[0014] Preferably, the high-melting-point polyolefin resin is prepared by grafting maleic anhydride or its derivative onto a polyolefin resin, and the melting point of the high-melting-point polyolefin is 140-165°C.

[0015] Preferably, the epoxidized thermoplastic elastomer is a thermoplastic elastomer that has undergone epoxidation treatment.

[0016] Preferably, the modifier is an epoxy acrylate polymer.

[0017] Preferably, the antioxidant is one or a mixture of two hindered phenols or aromatic amines.

[0018] Preferably, the method for preparing the double-sided adhesive frame is as follows:

[0019] S03 Ingredients and Premixing:

[0020] High melting point acid modified polypropylene resin, epoxidized thermoplastic elastomer, modifier and antioxidant are preheated and dried at 80-90℃ for 2 hours, and then put into a premixer and mixed at low speed at 60-80℃ for 10-15 minutes to obtain a premix.

[0021] S04 melt blending and granulation:

[0022] The premixed material is transferred to a twin-screw extruder and blended at 160–190°C and a screw speed of 100–400 rpm. The homogenized molten colloid is then extruded into strips through a die, cooled in a water bath, and then granulated to obtain hot melt adhesive particles with a particle size of 3–5 mm.

[0023] S05 Hot Melt Cast Coating:

[0024] Hot melt adhesive particles are applied to one side of a polyphenylene ether or polyphenylene sulfide substrate using a single-screw extrusion coating machine to form a hot melt adhesive layer with a thickness of 30-50 μm. After cooling and winding, a frame material with hot melt adhesive coated on one side is obtained. The other side is prepared using the same method to obtain a double-sided hot melt adhesive frame material.

[0025] The thickness of the single-sided adhesive frame is 25-100μm, of which the thickness of the substrate layer is 16-75μm and the thickness of the hot melt adhesive layer is 9-25μm.

[0026] The thickness of the double-sided hot melt adhesive frame is 150-260μm, of which the thickness of the substrate layer is 50-188μm, and the thickness of each of the two hot melt adhesive layers is 30-50μm.

[0027] The second technical problem to be solved by the present invention is to provide a method for preparing a single-cell encapsulation structure, which provides a single cell with good sealing effect and is not prone to leakage of reaction medium, in order to address the shortcomings of the existing technology.

[0028] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0029] A method for fabricating a single-cell encapsulation structure includes the following steps:

[0030] S1. Preparation and die-cutting of single-sided adhesive frame

[0031] The frame material coated with hot melt adhesive I on one side is die-cut to remove the active area, resulting in a single-sided adhesive frame with a frame-like edge. The die-cutting accuracy is controlled within ±0.05mm.

[0032] S2. Fabrication of the lower frame + membrane electrode monolayer structure

[0033] The single-sided adhesive frame obtained in step S1 is placed below and hot-pressed with the membrane electrode to obtain a single-layer frame structure of lower frame + membrane electrode.

[0034] S3. Preparation of the encapsulated membrane electrode

[0035] The double-sided hot melt adhesive II frame material is die-cut using the same die-cutting process as in step S1, and then hot-pressed with the single-layer frame adhesive film obtained in step S2 to obtain the encapsulated membrane electrode.

[0036] S4. Preparation of a single cell

[0037] The encapsulated membrane electrode obtained in step S3 is die-cut into the corresponding shape again, and then hot-pressed together with the anode and cathode plates to obtain a single cell.

[0038] Preferably, the hot pressing temperature in step S2 is 110-130°C, the hot pressing pressure is 0.4-0.8 MPa, and the hot pressing time is 30-60 s.

[0039] Preferably, the hot pressing temperature in step S3 is 120-140°C, the hot pressing pressure is 0.6-1.0 MPa, and the hot pressing time is 30-60 s;

[0040] The hot-pressing temperature in step S4 is 140–170°C, and the hot-pressing time is 60–120 seconds.

[0041] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0042] 1. This invention abandons the traditional approach of integral or single-layer sealing, and creatively designs a structure in which "a single-sided adhesive frame is directly bonded to one side of the membrane electrode, and a double-sided adhesive frame overlaps and is bonded to the other side of the membrane electrode." The single-sided adhesive layer is mainly responsible for tight bonding and initial sealing with one side of the membrane electrode; the double-sided adhesive layer provides overlapping sealing with the other side of the membrane electrode, reinforcing sealing with the single-sided adhesive, and final sealing with the electrode plate. This stepped design decomposes and strengthens the sealing function.

[0043] 2. Hot melt adhesive I is a high-adhesion polyolefin hot melt adhesive. By introducing a specific patented acid-modified polyolefin and epoxidized polybutadiene, it achieves extremely high initial adhesion and acid corrosion resistance to the membrane electrode catalyst layer (usually carbon-supported platinum) and PPS substrate, ensuring the reliability of the first seal. Hot melt adhesive II is a high-melting-point polyolefin hot melt adhesive. By using high-melting-point acid-modified polyolefin, epoxidized thermoplastic elastomer, and antioxidants, the adhesive layer maintains shape stability at high temperatures (preventing softening failure) and also has excellent elastic recovery and anti-aging capabilities, enabling it to withstand pressure fluctuations and temperature cycles under long-term operating conditions, ensuring the durability of the second and final seals. The two adhesive layers complement each other. The strong adhesion of hot melt adhesive I provides an anchoring foundation for the overall structure, while the high-temperature stability and elasticity of hot melt adhesive II provide long-term sealing protection, together forming a wide-temperature-range, aging-resistant, and highly reliable sealing system.

[0044] 3. This invention proposes a "stepwise hot pressing and layer-by-layer assembly" preparation process. Each step has clearly defined material, temperature, and pressure parameters. In particular, it employs a three-step method: first, preparing the "lower frame + membrane electrode" intermediate; then, combining it with the upper frame; and finally, assembling it with the electrode plates. By strictly controlling the die-cutting accuracy (±0.05mm) and the stepwise hot pressing parameters, the dimensional consistency and sealing uniformity of each battery package structure are ensured, making it suitable for mass production. The stepwise operation allows for quality checks in intermediate steps (such as checking for excess adhesive in the first hot pressing layer), reducing the scrap rate of the final product. The gradually increasing hot pressing temperature (from S2 to S3) also conforms to the physical characteristics of material melting and bonding, avoiding damage to the membrane electrode due to excessively high single-stage hot pressing temperature or pressure. Attached Figure Description

[0045] Figure 1 This is a structural diagram of a single cell in Embodiment 1 of the present invention;

[0046] The components are: 1. Membrane electrode; 2. Proton exchange membrane; 3. Catalyst layer; 4. Single-sided adhesive frame; 5. Double-sided hot melt adhesive frame; 6. Electrode plate; 7. Gas diffusion layer. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to the embodiments. Example 1

[0048] A single-cell encapsulation structure includes a membrane electrode 1, which includes a proton exchange membrane 2 and catalyst layers 3 located on both sides of the proton exchange membrane 2. One side of the catalyst layer 3 is bonded to a hot melt adhesive layer of a single-sided adhesive frame 4, and the other side of the catalyst layer 3 overlaps on a double-sided adhesive frame 5. After the catalyst layer 3 is bonded to the hot melt adhesive layer of the single-sided adhesive frame 4, the excess portion is bonded to one side of the adhesive layer of the double-sided adhesive frame 5. The upper and lower adhesive layers of the double-sided hot melt adhesive frame 5 are respectively provided with electrode plates 6. A gas diffusion layer 7 is formed between the membrane electrode 1 and the two electrode plates 6. Example 2

[0049] A single-cell packaging structure, with the same structural composition as in Example 1, wherein:

[0050] The single-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive I on one side and then die-cut to remove the active area. The hot melt adhesive I is composed of acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent in a weight ratio of 100:5:0.5:50. The diluent is a mixed solution of xylene and ethyl acetate in a mass ratio of 1:1. The acid-modified polyolefin resin is selected from the acid-modified polyolefin resin disclosed in Chinese Patent CN119193013B, and the epoxidized polybutadiene resin is selected from the epoxidized polybutadiene resin disclosed in paragraphs 42-43 of the specification of Chinese Patent CN117820978A.

[0051] The double-sided adhesive frame is made of polyphenylene ether as the base material, coated with hot melt adhesive II on both sides and then die-cut to remove the active area. The hot melt adhesive II is composed of high melting point polyolefin resin, epoxidized thermoplastic elastomer, modifier and antioxidant in a weight ratio of 100:10:0.5:0.5.

[0052] The high-melting-point polyolefin resin is prepared by grafting maleic anhydride onto a polyolefin resin. In this embodiment, the high-melting-point polyolefin resin is QB516 grafted with maleic anhydride by Mitsui Chemicals, with a melting point of 143°C.

[0053] The epoxidized thermoplastic elastomer is a thermoplastic elastomer that has undergone epoxidation treatment, specifically Daicel AT501.

[0054] The modifier is an epoxy acrylic polymer, specifically Nippon Oil G-1005S.

[0055] The antioxidant is a hindered phenolic antioxidant.

[0056] The thickness of the single-sided adhesive frame is 25μm, of which the thickness of the substrate layer is 16μm and the thickness of the hot melt adhesive layer is 9μm.

[0057] The thickness of the double-sided hot melt adhesive frame is 150μm, of which the thickness of the substrate layer is 50μm and the thickness of both hot melt adhesive layers is 50μm. Example 3

[0058] A single-cell packaging structure, with the same structural composition as in Example 1, wherein:

[0059] The single-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive I on one side and then die-cut to remove the active area. The hot melt adhesive I is composed of acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent in a weight ratio of 100:8:2:80. The diluent is a mixed solution of xylene and ethyl acetate in a mass ratio of 2:1. The acid-modified polyolefin resin is selected from the acid-modified polyolefin resin disclosed in Chinese Patent CN119193013B, and the epoxidized polybutadiene resin is selected from the epoxidized polybutadiene resin disclosed in paragraphs 42-43 of the specification of Chinese Patent CN117820978A.

[0060] The double-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive II on both sides and then die-cut to remove the active area. The hot melt adhesive II is composed of high melting point polyolefin resin, epoxidized thermoplastic elastomer, modifier and antioxidant in a weight ratio of 100:20:3:2.

[0061] The high-melting-point polyolefin resin is prepared by grafting maleic anhydride onto a polyolefin resin. In this embodiment, the high-melting-point polyolefin resin is Mitsui Chemicals' maleic anhydride-grafted QB550, with a melting point of 140°C.

[0062] The epoxidized thermoplastic elastomer is a thermoplastic elastomer that has undergone epoxidation treatment, specifically Daicel CT310.

[0063] The modifier is an epoxy acrylic polymer, specifically Nippon Oil G-0130SP.

[0064] The antioxidant is an aromatic amine antioxidant.

[0065] The thickness of the single-sided adhesive frame is 50μm, of which the thickness of the substrate layer is 25μm and the thickness of the hot melt adhesive layer is 25μm.

[0066] The thickness of the double-sided hot melt adhesive frame is 200μm, of which the thickness of the substrate layer is 120μm and the thickness of each of the two hot melt adhesive layers is 40μm. Example 4

[0067] A single-cell packaging structure, with the same structural composition as in Example 1, wherein:

[0068] The single-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive I on one side and then die-cut to remove the active area. The hot melt adhesive I is composed of acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent in a weight ratio of 100:10:3:100. The diluent is a mixed solution of xylene and ethyl acetate in a mass ratio of 1:2. The acid-modified polyolefin resin is selected from the acid-modified polyolefin resin disclosed in Chinese Patent CN119193013B, and the epoxidized polybutadiene resin is selected from the epoxidized polybutadiene resin disclosed in paragraphs 42-43 of the specification of Chinese Patent CN117820978A.

[0069] The double-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive II on both sides and then die-cut to remove the active area. The hot melt adhesive II is composed of high melting point polyolefin resin, epoxidized thermoplastic elastomer, modifier and antioxidant in a weight ratio of 100:30:5:3.

[0070] The high-melting-point polyolefin resin is prepared by grafting maleic anhydride onto a polyolefin resin. In this embodiment, the high-melting-point polyolefin resin is Mitsui Chemicals' QF500 grafted with maleic anhydride, with a melting point of 160°C.

[0071] The epoxidized thermoplastic elastomer is a thermoplastic elastomer that has undergone epoxidation treatment, specifically Daicel AT501.

[0072] The modifier is an epoxy acrylic polymer, specifically Nippon Oil G-0250SP.

[0073] The antioxidant is a mixture of hindered phenols or aromatic amines in a mass ratio of 1:1.

[0074] The thickness of the single-sided adhesive frame is 100μm, of which the thickness of the substrate layer is 75μm and the thickness of the hot melt adhesive layer is 25μm.

[0075] The thickness of the double-sided hot melt adhesive frame is 260μm, of which the thickness of the substrate layer is 188μm and the thickness of each of the two hot melt adhesive layers is 36μm. Example 5

[0076] The preparation method of the single-sided adhesive frame in Examples 2-4 includes the following steps:

[0077] S01, Preparation of hot melt adhesive liquid

[0078] Acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent are mixed in proportion, stirred at room temperature and 500-1000 r / min for 20-40 min, and the mixture is stirred evenly to obtain hot melt adhesive liquid.

[0079] S02, Preparation of single-sided adhesive frame

[0080] The hot melt adhesive liquid obtained in step S01 is filtered, coated onto a polyphenylene sulfide substrate with a thickness of 9-25μm using a doctor blade coater or CED coater, dried completely, and then a release film is attached and the substrate is rolled up and cured to obtain a single-sided adhesive frame.

[0081] The preparation method of the double-sided adhesive frame in Examples 2-4 includes the following steps:

[0082] S03 Ingredients and Premixing:

[0083] High melting point acid modified polypropylene resin, epoxidized thermoplastic elastomer, modifier and antioxidant are preheated and dried at 80-90℃ for 2 hours, and then put into a premixer and mixed at low speed at 60-80℃ for 10-15 minutes to obtain a premix.

[0084] S04 melt blending and granulation:

[0085] The premixed material is transferred to a twin-screw extruder and blended at 160–190°C and a screw speed of 100–400 rpm. The homogenized molten colloid is then extruded into strips through a die, cooled in a water bath, and then granulated to obtain hot melt adhesive particles with a particle size of 3–5 mm.

[0086] S05 Hot Melt Cast Coating:

[0087] Hot melt adhesive particles are applied to one side of a polyphenylene ether or polyphenylene sulfide substrate using a single-screw extrusion coating machine to form a hot melt adhesive layer with a thickness of 30-50 μm. After cooling and winding, a frame material with hot melt adhesive coated on one side is obtained. The other side is prepared using the same method to obtain a double-sided hot melt adhesive frame material. Example 6

[0088] The preparation method of the single-cell packaging structure in Examples 1-4 includes the following steps:

[0089] S1. Preparation and die-cutting of single-sided adhesive frame

[0090] The frame material coated with hot melt adhesive I on one side is die-cut, and the active area is removed to obtain a single-sided adhesive frame 3 with a frame-shaped edge. The die-cutting accuracy is controlled within ±0.05mm.

[0091] S2. Fabrication of the lower frame + membrane electrode monolayer structure

[0092] The single-sided adhesive frame obtained in step S1 is placed at the bottom and hot-pressed with the membrane electrode. The hot-pressing temperature is 110-130℃, the hot-pressing pressure is 0.4-0.8MPa, and the hot-pressing time is 30-60s, thus obtaining a single-layer frame structure of bottom frame + membrane electrode.

[0093] S3. Preparation of the encapsulated membrane electrode

[0094] The double-sided hot melt adhesive II frame material is die-cut using the same die-cutting process as in step S1. Then, it is hot-pressed with the single-layer frame adhesive film obtained in step S2. The hot-pressing temperature is 120-140℃, the hot-pressing pressure is 0.6-1.0MPa, and the hot-pressing time is 30-60s to obtain the encapsulated membrane electrode.

[0095] S4. Preparation of a single cell

[0096] The encapsulated membrane electrode obtained in step S3 is die-cut into the corresponding shape again, and then hot-pressed together with the anode and cathode plates. The hot-pressing temperature is 140-170℃ and the hot-pressing time is 60-120s to obtain a single cell.

[0097] The single cells in Examples 2-4 were tested, and the test indicators and results are shown in Tables 1 and 2, respectively:

[0098] Table 1

[0099] Test Project Performance indicators Test methods Peel strength (g / 20mm) of single-sided adhesive frame and membrane electrode >1300 or CCM layering Single-sided adhesive frame + CCM + single-sided adhesive frame hot pressing 20mm wide, 100mm / min, 180° peeling Peel strength (g / 20mm) for single-sided and double-sided adhesive borders >2000g / 20mm Single-sided adhesive frame + double-sided adhesive frame hot-pressed 20mm wide, 100mm / min, 180° peeling Peel strength (g / 20mm) of double-sided adhesive frame and metal electrode plate >4000g / 20mm Double-sided adhesive frame + metal electrode plate hot pressing 20mm wide, 100mm / min, 180° peeling

[0100] Table 2

[0101] Test Project Example 2 Example 3 Example 4 Peel strength (g / 20mm) of single-sided adhesive frame and membrane electrode 1530 2170 3320 Peel strength (g / 20mm) for single-sided and double-sided adhesive borders 3150 3425 4315 Peel strength (g / 20mm) 5 Double-sided adhesive frame and metal electrode plate 5560 6735 7860

[0102] Using an airtightness testing device, the single-cell modules from Examples 2-4 were purged with 0.3 MPa nitrogen gas. The contact points between the frame membrane and the membrane electrode and plates were tested. The leakage rate was determined by the soap bubble method or a gas flow meter (required to be ≤1×10). -6 P·am 3 The test results are shown in Table 3 ( / s).

[0103] Table 3

[0104] Test Project Example 2 Example 3 Example 4 Air tightness (Pa·m³ / s) <![CDATA[0.38×10⁻ 6 ]]> <![CDATA[0.24×10⁻ 6 ]]> <![CDATA[0.51×10⁻ 6 ]]>

[0105] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A single-cell encapsulation structure, comprising a membrane electrode, wherein the membrane electrode includes a proton exchange membrane and catalyst layers located on both sides of the proton exchange membrane, characterized in that: The catalyst layer on one side is bonded to the hot melt adhesive layer of the single-sided adhesive frame, and the catalyst layer on the other side overlaps on the double-sided adhesive frame. After the catalyst layer is bonded to the hot melt adhesive layer of the single-sided adhesive frame, the excess part is bonded to the double-sided adhesive frame. Electrode plates are respectively provided on the upper and lower sides of the double-sided adhesive frame, and a gas diffusion layer is provided between the membrane electrode and the two electrode plates. The single-sided adhesive frame is made of polyphenylene sulfide as the base material, coated with hot melt adhesive I on one side and then die-cut to remove the active area. The hot melt adhesive I is composed of acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent in a weight ratio of 100:5-10:0.5-3:50-100. The diluent is a mixed solvent of xylene and ethyl acetate. The method for preparing the single-sided adhesive frame is as follows: S01, Preparation of hot melt adhesive liquid Acid-modified polyolefin resin, epoxidized polybutadiene resin, isocyanate curing agent and diluent are mixed in proportion, stirred at room temperature and 500-1000 r / min for 20-40 min, and the mixture is stirred evenly to obtain hot melt adhesive liquid. S02, Preparation of single-sided adhesive frame The hot melt adhesive liquid obtained in step S01 is filtered, coated onto a polyphenylene sulfide substrate with a thickness of 9-25μm using a doctor blade coater or CED coater, dried completely, and then a release film is attached and the substrate is rolled up and cured to obtain a single-sided adhesive frame. The double-sided adhesive frame is made of polyphenylene ether or polyphenylene sulfide as the base material, coated with hot melt adhesive II on both sides and then die-cut to remove the active area. The hot melt adhesive II is composed of high melting point polyolefin resin, epoxidized thermoplastic elastomer, modifier and antioxidant in a weight ratio of 100:10-30:0.5-5:0.5-3. The high-melting-point polyolefin resin is obtained by grafting maleic anhydride onto a polyolefin resin, and the melting point of the high-melting-point polyolefin resin is 140-165°C. The modifier is an epoxy acrylic polymer; The epoxidized thermoplastic elastomer is a thermoplastic elastomer that has undergone epoxidation treatment; The antioxidant is one or a mixture of two hindered phenols or aromatic amines; The method for preparing the double-sided adhesive frame is as follows: S03 Ingredients and Premixing: High-melting-point acid-modified polypropylene resin, epoxidized thermoplastic elastomer, epoxy acrylic polymer and antioxidant are preheated and dried at 80-90℃ for 2 hours, and then put into a premixer and mixed at low speed at 60-80℃ for 10-15 minutes to obtain a premix. S04 melt blending and granulation: The premixed material is transferred to a twin-screw extruder and blended at 160–190°C and a screw speed of 100–400 rpm. The homogenized molten colloid is then extruded into strips through a die, cooled in a water bath, and then granulated to obtain hot melt adhesive particles with a particle size of 3–5 mm. S05 Hot Melt Cast Coating: Hot melt adhesive particles are applied to one side of a polyphenylene ether or polyphenylene sulfide substrate using a single-screw extrusion coating machine to form a hot melt adhesive layer with a thickness of 30-50 μm. After cooling and winding, a frame material with hot melt adhesive coated on one side is obtained. The other side is prepared using the same method to obtain a double-sided adhesive frame material.

2. The single-cell packaging structure as described in claim 1, characterized in that: The thickness of the single-sided adhesive frame is 25-100μm, of which the thickness of the substrate layer is 16-75μm and the thickness of the hot melt adhesive layer is 9-25μm.

3. The single-cell packaging structure as described in claim 1, characterized in that: The thickness of the double-sided adhesive frame is 150-260μm, of which the thickness of the substrate layer is 50-188μm, and the thickness of each of the two hot melt adhesive layers is 30-50μm.

4. A method for preparing a single-cell packaging structure as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation and die-cutting of single-sided adhesive frame The frame material coated with hot melt adhesive I on one side is die-cut to remove the active area, resulting in a single-sided adhesive frame with a frame-like edge. The die-cutting accuracy is controlled within ±0.05mm. S2. Fabrication of the lower frame + membrane electrode monolayer structure The single-sided adhesive frame obtained in step S1 is placed below and hot-pressed with the membrane electrode to obtain a single-layer frame structure of lower frame + membrane electrode. S3. Preparation of the encapsulated membrane electrode The double-sided hot melt adhesive II frame material is die-cut using the same die-cutting process as in step S1, and then hot-pressed with the single-layer frame adhesive film obtained in step S2 to obtain the encapsulated membrane electrode. S4. Preparation of a single cell The encapsulated membrane electrode obtained in step S3 is die-cut into the corresponding shape again, and then hot-pressed together with the anode and cathode plates to obtain a single cell.

5. The method for preparing a single-cell packaging structure as described in claim 4, characterized in that: In step S2, the hot pressing temperature is 110–130℃, the hot pressing pressure is 0.4–0.8 MPa, and the hot pressing time is 30–60 s.

6. The method for preparing a single-cell packaging structure as described in claim 4, characterized in that: In step S3, the hot pressing temperature is 120–140°C, the hot pressing pressure is 0.6–1.0 MPa, and the hot pressing time is 30–60 s. The hot-pressing temperature in step S4 is 140–170°C, and the hot-pressing time is 60–120 seconds.

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