A thermoset multilayer composite bipolar plate and processing
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-15
- Publication Date
- 2026-08-11
AI Technical Summary
目前商业化的双极板主要是无孔石墨板和改性金属板，无孔石墨板是由石墨和可石墨化的树脂混合，经复杂的石墨化工艺处理所得；这种方法制备的双极板存在强度低，需要3-5mm的厚度才能保持良好的机械性能，此外为了保证良好的气密性，这种石墨板需要多次浸渍树脂，且流场的机加工工艺费时费力，成本高；金属板易于批量化生产，机械性能好，但是存在在酸性介质中耐蚀性较差，与气体扩散层接触电阻较大的特点；
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of bipolar plate processing, specifically to a thermosetting multilayer composite bipolar plate and its processing technology. Background Technology
[0002] Bipolar plates are one of the important components of fuel cell stacks, accounting for about 20-40% of the cost of the stack. They are the "skeleton" of the stack. They are stacked with membrane electrode assemblies to form the stack. In fuel cells, they play a role in supporting, collecting current, providing channels for coolant, and separating oxidant and reductant. Currently, commercially available bipolar plates are mainly non-porous graphite plates and modified metal plates. Non-porous graphite plates are made by mixing graphite and graphitizable resin and then processing them through a complex graphitization process. Bipolar plates prepared by this method have low strength and require a thickness of 3-5 mm to maintain good mechanical properties. In addition, in order to ensure good airtightness, these graphite plates need to be impregnated with resin multiple times, and the machining process of the flow field is time-consuming, labor-intensive, and costly. Metal plates are easy to mass-produce and have good mechanical properties, but they have poor corrosion resistance in acidic media and high contact resistance with the gas diffusion layer. Metallic materials possess excellent electrical conductivity, liquid resistance, and bipolar plate processing performance. However, the electrolyte system used in vanadium redox flow batteries exhibits strong acidity and redox properties, making commonly used metallic materials unsuitable due to their stability. Hard graphite is a commonly used bipolar plate material for vanadium redox flow batteries, characterized by high electrical conductivity, good chemical stability, and excellent liquid resistance. However, its high cost and brittleness limit its practical application. Carbon-plastic conductive composite material is another type of bipolar plate material for all-vanadium redox flow batteries. The main advantages of carbon-plastic conductive composite material are simple processing, low cost, and easy mass production. It is the most promising material for significantly reducing the cost of bipolar plates, and therefore it has received increasing attention. Summary of the Invention
[0003] The purpose of this invention is to provide a thermosetting multilayer composite bipolar plate and its processing technology to solve the above-mentioned defects caused by the prior art.
[0004] A thermosetting multilayer composite bipolar plate includes a positioning plate one, with slots on both sides of the positioning plate one, a positioning plate two above the positioning plate one, and an insulating pad below the positioning plate two. Both sides of the positioning plate two are provided with locking strips. An anode plate is provided inside the cavity formed by the positioning plate two and the positioning plate one. A cathode plate is provided directly below the anode plate. A sealing gasket is provided between the anode plate and the cathode plate. The outer side of the positioning plate is provided with liquid flow channels at equal intervals, and the outer side of the positioning plate is provided with heat dissipation holes.
[0005] S1: Molding and Segmentation: Conductive carbon powder (such as graphite powder, carbon black, carbon fiber, etc.) is uniformly mixed with thermoplastic resin (polyethylene, polyvinyl chloride, polypropylene, etc.) and inhibitors, release agents, etc., and carbon-plastic composite bipolar plates are prepared by injection molding or compression molding to form positioning plate one and positioning plate two. Simultaneously, single-plate rollers are used to roll two single-plates at two separate workstations, forming multiple sets of anode and cathode plates of the same size. The required flow field is pressed onto the upper or lower surfaces of the raw material plate. The single-plate rollers arrange several plate reaction flow fields on the circumferential surface, and several single-plate flow fields can be rolled on one circumference to extrude and roll the metal material plate. The molding conditions for positioning plate one and positioning plate two include preheating at 100-180°C, pre-pressing at 0.1-10.0MPa, hot pressing at 100-240°C, 0.1-20MPa, and 10-1200s, and finally cooling for 10-1800s to obtain the composite material electrode matrix and the nanocomposite bipolar plate matrix. S2: Quality Inspection: After the individual electrode plates are manufactured, each electrode plate undergoes quality inspection to determine whether the dimensions, thickness, and tolerances of the ridges and grooves meet the design requirements. S3: Laser welding: In this step, the anode and cathode plates that meet the quality requirements are welded together by laser welding to form a complete bipolar plate. After welding, the coolant chamber of the bipolar plate will be completely sealed, and finally, its sealing performance will be tested. S4: Air tightness test: The two trays are repositioned by the secondary positioning of the two bipolar plates at the end of the second layer of the double speed chain. The two bipolar plates are transferred to the air tightness test transfer table by the transfer robot. The transfer robot combines four bipolar plates into a group through two transfers. The air tightness test line robot transfers the group of four bipolar plates to the air tightness test table. S5: Coating Treatment: The bipolar plates will then undergo a coating treatment after welding to improve their corrosion resistance. Currently, the commonly used coating method is PVD (Polydioxanone). S6: Sealing: The final step is to fill the sealing material into the sealing groove designed on the bipolar plate; S7: Assembly: The grooves in the middle of the two sets of symmetrically arranged carbon-plastic composite plates are used to position the multiple sets of metal plates. Then, the other set of carbon-plastic composite plates is installed on the top of the carbon-plastic composite plates, and the multiple sets of welded bipolar plates are positioned.
[0006] Preferably, the second positioning plate is connected to the outer side of the slot via a locking strip.
[0007] Preferably, the carbon-plastic composite material plate has a width of 600 mm and a thickness of 1 mm.
[0008] Preferably, the carbon-plastic composite material has a resistivity of 0.14 Ω·cm and a bending strength of 51 MPa.
[0009] Preferably, the carbon-plastic composite material sheet material is processed by a screw extruder with a barrel temperature of 160-250°C, a die temperature of 180-240°C, and a main extruder speed of 5-15 rpm.
[0010] Preferably, the extrusion calender is used to prepare carbon-plastic conductive composite material plates; the heating temperature of each working section of the extruder is usually 100-400℃, the extruder head temperature is usually 100-400℃, and calendering is achieved by a roller method.
[0011] Preferably, the optimal conditions for the composite material electrode matrix are preheating at 110–140°C, pre-pressing at 0.5–5.0 MPa, followed by hot pressing at 160–230°C, 5.0–20 MPa, and 300–900 s, and finally cooling for 300–600 s. Compared with the prior art, the present invention has the following advantages: 1. Carbon-plastic composite bipolar plates not only have high conductivity, good liquid resistance and mechanical properties, but also can be as thin as 0.1 mm and have an area of 2 m2 or even larger. This is something that the commonly used processing methods for carbon-plastic conductive composite bipolar plates, such as compression molding and injection molding, cannot achieve. This method has high production efficiency, can effectively reduce the cost of bipolar plates, and is conducive to the commercialization of batteries.
[0012] 2. Positioning plates one and two are used to position the bipolar plates, preventing misalignment between the membrane electrode assemblies and bipolar plates during fuel cell stack assembly. With the same amount added, the composite plate using carbon black as the conductive filler exhibits significantly higher conductivity than the composite plate using graphite powder and carbon fiber as conductive fillers. This may be because carbon black has extremely small particle sizes (nanoscale), resulting in more particles present at the same content, increasing their contact probability with the resin and making it easier for them to cross-link and form a conductive network.
[0013] 3. Although carbon black has good electrical conductivity, its small particle size (nanoscale) results in a large volumetric volume for the same mass fraction, affecting the flowability of the polymer matrix and leading to poor processability and formability of the composite material. Carbon fiber, on the other hand, is a fibrous filler that easily forms a network within the matrix, thus exhibiting better processability and formability. Therefore, combining different types of conductive fillers can improve the overall performance of the composite material. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention.
[0015] Figure 2 This is a schematic diagram of the positioning plate of the present invention.
[0016] in: 1. Positioning plate one; 2. Positioning plate two; 3. Insulating rubber pad; 4. Clip; 5. Anode plate; 6. Cathode plate; 7. Sealing rubber pad; 8. Liquid flow channel; 9. Slot; 10. Heat dissipation hole; Detailed Implementation
[0017] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0018] like Figures 1 to 2 As shown, a thermosetting multilayer composite bipolar plate includes a positioning plate 1, with slots 9 on both sides of the positioning plate 1, a positioning plate 2 directly above the positioning plate 1, and an insulating pad 3 directly below the positioning plate 2. Both sides of the positioning plate 2 are provided with locking strips 4. An anode plate 5 is provided inside the cavity formed by the positioning plate 2 and the positioning plate 1. A cathode plate 6 is provided directly below the anode plate 5. A sealing gasket 7 is provided between the anode plate 5 and the cathode plate 6. The outer side of the positioning plate 1 is provided with liquid flow channels 8 at equal intervals, and the outer side of the positioning plate 1 is provided with heat dissipation holes 10.
[0019] In this embodiment, the second positioning plate 2 is connected to the outer side of the slot by a clip connected to the outer side, and is connected to the positioning plate 1 by the clip provided on the outer side of the second positioning plate 2.
[0020] In this embodiment, the carbon-plastic composite material plate has a width of 600mm and a thickness of 1mm. It is formed by the carbon-plastic composite material being evenly spaced between positioning plate 1 and positioning plate 2 to form an integral bipolar plate.
[0021] In this embodiment, the carbon-plastic composite material has a resistivity of 0.14 Ω·cm and a bending strength of 51 MPa.
[0022] In this embodiment, the carbon-plastic composite material is processed by a screw extruder with a barrel temperature of 160–250°C, a die temperature of 180–240°C, and a main extruder speed of 5–15 rpm.
[0023] In this embodiment, the extrusion calender is used to prepare carbon-plastic conductive composite material plates; the heating temperature of each working section of the extruder is usually 100-400°C, the extruder head temperature is usually 100-400°C, and calendering is achieved by a roller method.
[0024] In this embodiment, the optimal conditions for the composite material electrode substrate are preheating at 110–140°C, pre-pressing at 0.5–5.0 MPa, followed by hot pressing at 160–230°C, 5.0–20 MPa, and 300–900 s, and finally cooling for 300–600 s.
[0025] In practical applications, this thermosetting multilayer composite bipolar plate and its processing technology include the following steps: S1: Molding and Segmentation: Conductive carbon powder (such as graphite powder, carbon black, carbon fiber, etc.) is uniformly mixed with thermoplastic resin (polyethylene, polyvinyl chloride, polypropylene, etc.) and inhibitors, release agents, etc., and carbon-plastic composite bipolar plates are prepared by injection molding or compression molding to form positioning plate one and positioning plate two. Simultaneously, single-plate rollers are used to roll two single-plates at two separate workstations, forming multiple sets of anode and cathode plates of the same size. The required flow field is pressed onto the upper or lower surfaces of the raw material plate. The single-plate rollers arrange several plate reaction flow fields on the circumferential surface, and several single-plate flow fields can be rolled on one circumference to extrude and roll the metal material plate. S2: Quality Inspection: After the individual electrode plates are manufactured, each electrode plate undergoes quality inspection to determine whether the dimensions, thickness, and tolerances of the ridges and grooves meet the design requirements. S3: Laser welding: In this step, the anode and cathode plates that meet the quality requirements are welded together by laser welding to form a complete bipolar plate. After welding, the coolant chamber of the bipolar plate will be completely sealed, and finally, its sealing performance will be tested. S4: Air tightness test: The two trays are repositioned by the secondary positioning of the two bipolar plates at the end of the second layer of the double speed chain. The two bipolar plates are transferred to the air tightness test transfer table by the transfer robot. The transfer robot combines four bipolar plates into a group through two transfers. The air tightness test line robot transfers the group of four bipolar plates to the air tightness test table. S5: Coating Treatment: The bipolar plates will then undergo a coating treatment after welding to improve their corrosion resistance. Currently, the commonly used coating method is PVD (Polydioxanone). S6: Sealing: The final step is to fill the sealing material into the sealing groove designed on the bipolar plate; S7: Assembly: The grooves in the middle of the two sets of symmetrically arranged carbon-plastic composite plates are used to position the multiple sets of metal plates. Then, the other set of carbon-plastic composite plates is installed on the top of the carbon-plastic composite plates, and the multiple sets of welded bipolar plates are positioned.
[0026] Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not exhaustive. All modifications within the scope of this invention or its equivalents are included in this invention.
Claims
1. A thermoset multilayer composite bipolar plate, characterized by: It includes a positioning plate (1), with slots (9) on both sides of the positioning plate (1), a positioning plate (2) is provided directly above the positioning plate (1), and an insulating pad (3) is provided directly below the positioning plate (2). Both sides of the positioning plate 2 (2) are provided with clips (4). An anode plate (5) is provided inside the cavity formed by the positioning plate 2 (2) and the positioning plate 1 (1). A cathode plate (6) is provided directly below the anode plate (5). A sealing gasket (7) is provided between the anode plate (5) and the cathode plate (6). The outer side of the positioning plate (1) is provided with liquid flow channels (8) at equal intervals, and the outer side of the positioning plate (1) is provided with heat dissipation holes (10).
2. A thermoset multilayer composite bipolar plate according to claim 1, wherein: The positioning plate 2 (2) is connected to the outer side of the slot (9) by a card strip (4) connected to the outer side.
3. A processing technology for thermosetting multilayer composite bipolar plates, comprising the following steps: S1: Molding and Segmentation: Conductive carbon powder (such as graphite powder, carbon black, carbon fiber, etc.) is uniformly mixed with thermoplastic resin (polyethylene, polyvinyl chloride, polypropylene, etc.) and inhibitors, release agents, etc., and carbon-plastic composite bipolar plates are prepared by injection molding or compression molding to form positioning plate one and positioning plate two. Simultaneously, single-plate rollers are used to roll two single-plates at two separate workstations, forming multiple sets of anode and cathode plates of the same size. The required flow field is pressed onto the upper or lower surfaces of the raw material plate. The single-plate rollers arrange several plate reaction flow fields on the circumferential surface, and several single-plate flow fields can be rolled on one circumference to extrude and roll the metal material plate. The molding conditions for positioning plate one and positioning plate two include preheating at 100-180°C, pre-pressing at 0.1-10.0MPa, hot pressing at 100-240°C, 0.1-20MPa, and 10-1200s, and finally cooling for 10-1800s to obtain the composite material electrode matrix and the nanocomposite bipolar plate matrix. S2: Quality Inspection: After the manufacturing of a single electrode plate is completed, each electrode plate is subjected to quality inspection to determine whether the dimensions, thickness and error of the ridges and grooves meet the design requirements. S3: Laser welding: In this step, the anode and cathode plates that meet the quality requirements are welded together by laser welding to form a complete bipolar plate. After welding, the coolant chamber of the bipolar plate will be completely sealed, and finally, its sealing performance will be tested. S4: Air tightness test: The two trays are repositioned by the secondary positioning of the two bipolar plates at the end of the second layer of the double speed chain. The two bipolar plates are transferred to the air tightness test transfer table by the transfer robot. The transfer robot combines four bipolar plates into a group through two transfers. The air tightness test line robot transfers the group of four bipolar plates to the air tightness test table. S5: Coating treatment: The bipolar plates will then be coated after welding to improve their corrosion resistance. The commonly used coating method is PVD. S6: Sealing: The final step is to fill the sealing material into the sealing groove designed on the bipolar plate; S7: Assembly: The grooves in the middle of the two sets of symmetrically arranged carbon-plastic composite plates are used to position the multiple sets of metal plates. Then, the other set of carbon-plastic composite plates is installed on the top of the carbon-plastic composite plates, and the multiple sets of welded bipolar plates are positioned.
4. A process for manufacturing thermoset multilayer composite bipolar plates according to claim 3, characterized in that: The carbon-plastic composite material plate has a width of 600mm and a thickness of 1mm.
5. A process for making a thermoset multilayer composite bipolar plate according to claim 3, wherein: The carbon-plastic composite material has a resistivity of 0.14 Ω·cm and a bending strength of 51 MPa.
6. A process for making a thermoset multilayer composite bipolar plate according to claim 3, wherein: The carbon-plastic composite material sheet material is processed by a screw extruder with a barrel temperature of 160-250℃, a die temperature of 180-240℃, and a main extruder speed of 5-15 rpm.
7. A process for manufacturing thermoset multilayer composite bipolar plates according to claim 6, characterized in that: The extruder is used to prepare carbon-plastic composite material sheets; the heating temperature of each working section of the extruder is usually 100-400℃, the extruder head temperature is usually 100-400℃, and calendering is achieved by a roller method.
8. A thermoset multilayer composite bipolar plate processing method according to claim 6, characterized in that: The optimal conditions for the carbon-plastic composite material substrate are preheating at 110–140°C, pre-pressing at 0.5–5.0 MPa, followed by hot pressing at 160–230°C, 5.0–20 MPa, and 300–900 s, and finally cooling for 300–600 s.