A lightweight composite bipolar plate for low power proton exchange membrane fuel cells

Abstract

A kind of lightweight composite bipolar plate of low-power proton exchange membrane fuel cell, substrate layer made of resin-based composite material with carbon fiber content of 30%~50% is arranged with multiple leaf-shaped floating points in array distribution on its surface, so that the surface of substrate layer forms the concave-convex structure of conductive network, and the middle part of floating point is flow channel groove, so that the gap between floating points and flow channel groove form bionic flow channel.The bipolar plate with array distribution of floating points can not only effectively improve mechanical strength, but also improve the uniformity of reaction gas distribution, thereby improving the conversion efficiency of electric energy and conductive performance, and its structure is simple and easy to manufacture, which can effectively reduce the complexity of process and production cost.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to the structure of a bipolar plate for a proton exchange membrane fuel cell. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that converts chemical energy into electrical energy using hydrogen and oxygen as fuel. The fuel cell is equipped with bipolar plates with flow-guiding structures, which play important roles in supporting and fixing the PEMFC assembly, separating fuel gas and oxidizing gas, and collecting conduction current.

[0003] Bipolar plates are classified into graphite bipolar plates, metal bipolar plates, and composite material bipolar plates according to their material type. Graphite bipolar plates are manufactured by machining, which has a high manufacturing cost and high brittleness; metal bipolar plates are manufactured by stamping, which has high mechanical strength but is prone to corrosion and the production process of surface coating is extremely complex; composite material bipolar plates have poor electrical conductivity and are heavy. Utility Model Content

[0004] The purpose of this invention is to provide a low-power fuel cell bipolar plate that is lightweight, highly conductive, corrosion-resistant, and low-cost.

[0005] The lightweight composite bipolar plate for low-power proton exchange membrane fuel cells of this invention includes a substrate layer, a conductive layer covering the substrate layer, and a corrosion-resistant layer covering the conductive layer. The surface of the substrate layer has multiple raised floating points arranged in an array, with gaps between adjacent floating points. The floating points are leaf-shaped, with a large middle and small ends and arc-shaped sides. The middle of the floating points is provided with flow channel grooves along mutually parallel directions.

[0006] The lightweight composite bipolar plate for low-power proton exchange membrane fuel cells described in this invention features leaf-shaped floating points on the surface of a substrate layer, creating a conductive network with an uneven surface. The gaps between the floating points and the flow channels in the center of each floating point are correspondingly arranged along the array direction, forming different biomimetic flow channel structures. Hydrogen or air supplied to the substrate layer flows along these biomimetic channels, expelling the water generated during the reaction outside the battery. Simultaneously, cooling water can also flow along these channels, carrying away the heat generated during the reaction from the fuel cell stack and controlling the stack at a suitable temperature. This type of bipolar plate, with its arrayed floating points, not only effectively improves mechanical strength but also enhances the uniformity of the reactant gas distribution, thereby improving energy conversion efficiency and conductivity. Furthermore, its simple structure and easy fabrication effectively reduce process complexity and production costs.

[0007] Preferably, the substrate layer is made of a resin-based composite material with a carbon fiber content of 30% to 50%.

[0008] Preferably, the thickness of the substrate layer is 0.5~1.5mm.

[0009] Preferably, the conductive layer is a coating and is made of graphene or carbon nanotube material.

[0010] Preferably, the thickness of the conductive layer is 10~1100nm.

[0011] Preferably, the corrosion-resistant layer is a polymer film, made of polyaniline or polypyrrole material.

[0012] Preferably, the thickness of the corrosion-resistant layer is 0.1~1μm.

[0013] Preferably, the substrate layer has a gas inlet and a gas outlet at both ends, a floating point is set on the substrate layer between the gas inlet and the gas outlet, and the flow channel is set in a straight line with its two ends pointing to the two ends of the substrate layer.

[0014] Preferably, the bottom surface of the flow channel is flush with the surface of the substrate layer, and the depth of the flow channel is 0.2~0.8mm.

[0015] Preferably, the density of flow channel grooves on the substrate layer is 5~10 grooves / cm².

[0016] By using the lightweight composite bipolar plate configuration described above for low-power proton exchange membrane fuel cells, the structural strength and conductivity of the bipolar plate can be further improved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the lightweight composite bipolar plate for a low-power proton exchange membrane fuel cell.

[0018] Figure 2 This is a top view schematic diagram of the lightweight composite bipolar plate of a low-power proton exchange membrane fuel cell.

[0019] Figure 3 yes Figure 1 The diagram shows a partial structural schematic of a lightweight composite bipolar plate for a low-power proton exchange membrane fuel cell. Detailed Implementation

[0020] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0021] It should be noted that if any directional indication (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.) is involved in the embodiments of this utility model, the directional indication is only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] If the embodiments of this utility model involve descriptions such as "first" or "second," such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0023] This invention proposes a lightweight composite bipolar plate for low-power proton exchange membrane fuel cells.

[0024] The lightweight composite bipolar plate for low-power proton exchange membrane fuel cells in this embodiment includes a substrate layer 1, a conductive layer covering the substrate layer, and a corrosion-resistant layer covering the conductive layer. The surface of the substrate layer has a plurality of raised floating points 4 arranged in an array, with gaps 5 between adjacent floating points. The floating points are leaf-shaped with a large middle and small ends and arc-shaped sides. The middle of the floating points is provided with flow channel grooves 6 in mutually parallel directions.

[0025] like Figure 1-3 As shown, leaf-shaped floating points are arranged on the surface of the substrate layer, forming a conductive network with an uneven structure on the surface of the substrate layer. The gaps between each floating point and the flow channel grooves in the middle of each floating point are respectively arranged along the array direction, so that they form different biomimetic flow channel structures. Hydrogen or air delivered to the substrate layer flows along the biomimetic flow channels, and the water generated by the reaction is discharged out of the battery. At the same time, cooling water can also flow along these flow channels, thereby carrying away the heat generated by the reaction from the stack and controlling the stack at a suitable temperature.

[0026] The lightweight composite bipolar plate for low-power proton exchange membrane fuel cells described above has a substrate layer 1 made of carbon fiber reinforced resin matrix composite material, specifically a resin matrix composite material with a carbon fiber content of 30%~50%, and a thickness of 0.5~1.5mm. The conductive layer is a coating made of graphene or carbon nanotube material, with a thickness of 10~1100nm. The corrosion-resistant layer is a polymer film, specifically made of polyaniline or polypyrrole material, with a thickness of 0.1~1μm. In the fabrication of the bipolar plate, graphene is grown on the carbon fiber surface by chemical vapor deposition (CVD) to pre-treat the carbon fiber; then, modified carbon fiber is mixed with thermosetting resin and cured to form the substrate layer; subsequently, the conductive and corrosion-resistant layers are sprayed onto the substrate layer, and flow channels are processed by laser engraving to improve its fabrication precision. Extensive testing has demonstrated that this bipolar plate structure can further improve the hardness of the bipolar plate and reduce its weight.

[0027] The lightweight composite bipolar plate for the low-power proton exchange membrane fuel cell described above has a gas inlet 7 and a gas outlet 8 at both ends of the substrate layer 1. A float 4 is located on the substrate layer between the gas inlet and the gas outlet. The flow channel 6 is linearly arranged with its two ends pointing towards the two ends of the substrate layer. The bottom surface of the flow channel 6 is flush with the surface of the substrate layer 1 to ensure smooth and stable airflow and water flow. The depth of the flow channel 6 is 0.2~0.8mm, and the density of the flow channel 6 on the substrate layer 1 is 5~10 channels / cm². This further improves the energy conversion efficiency and electrical conductivity.

[0028] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A lightweight composite bipolar plate for low power proton exchange membrane fuel cells comprising a substrate layer (1), an electrically conductive layer coated on the substrate layer and a corrosion resistant layer coated on the electrically conductive layer, characterized in that: The surface of the substrate layer has multiple raised floating points (4) arranged in an array, with gaps (5) between adjacent floating points. The floating points are leaf-shaped with a large middle and small ends and arc-shaped sides. The middle part of the floating points is provided with flow channel grooves (6) in mutually parallel directions.

2. The lightweight composite bipolar plate for low power proton exchange membrane fuel cells according to claim 1, characterized by: The thickness of the substrate layer (1) is 0.5~1.5mm.

3. The lightweight composite bipolar plate for low power proton exchange membrane fuel cells of claim 1, wherein: The conductive layer is a coating material made of graphene or carbon nanotubes.

4. The lightweight composite bipolar plate for a low-power proton exchange membrane fuel cell according to claim 1, characterized in that: The thickness of the conductive layer is 10~1100nm.

5. The low power proton exchange membrane fuel cell lightweight composite bipolar plate of claim 1, wherein: The corrosion-resistant layer is a polymer film made of polyaniline or polypyrrole material.

6. The low power proton exchange membrane fuel cell lightweight composite bipolar plate of claim 1, wherein: The thickness of the corrosion-resistant layer is 0.1~1μm.

7. The low power proton exchange membrane fuel cell lightweight composite bipolar plate of claim 1, wherein: The substrate layer (1) has a gas inlet (7) and a gas outlet (8) at its two ends respectively. The floating point (4) is located on the substrate layer between the gas inlet and the gas outlet. The flow channel (6) is arranged in a straight line and its two ends point to the two ends of the substrate layer respectively.

8. The lightweight composite bipolar plate for low power proton exchange membrane fuel cells according to claim 1 or 7, characterized in that: The bottom surface of the flow channel (6) is flush with the surface of the substrate layer (1), and the depth of the flow channel is 0.2~0.8mm.

9. The lightweight composite bipolar plate for low power proton exchange membrane fuel cells according to claim 1 or 7, characterized in that: The density of flow channel grooves (6) on the substrate layer (1) is 5~10 grooves / cm².

Images