Bipolar plate and PEM electrolytic bath

Abstract

The triangular runners are arranged on the inner sides of an anode plate and a cathode plate of the PEM electrolytic bath, the vertex angle is 30-90 degrees (preferably 45-60 degrees), the depth of each runner is 0.5-5 mm, the width of each runner is 0.5-5 mm, the interval of each runner is 1-10 mm, and the triangular runners can be arranged in parallel, staggered and the like. The anode plate and the cathode plate can be made of metal (such as stainless steel and titanium alloy) or graphite materials, and cooling channels can be arranged outside the anode plate and the cathode plate. The membrane electrode assembly comprises a proton exchange membrane (such as a perfluorosulfonic acid membrane), an anode catalyst layer (such as iridium dioxide) and a cathode catalyst layer (such as platinum or platinum alloy). According to the electrolytic cell, fluid disturbance is increased, gas discharge is improved, membrane electrode hydrogen attachment is effectively reduced, proton conduction and electrode reaction activity are improved, and compared with a traditional electrolytic cell, under the same condition, the current density, the hydrogen production efficiency and the hydrogen purity are higher, energy consumption and cost are lower, and good application prospects and economic benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of proton exchange membrane (PEM) electrolyzers, and in particular to a PEM electrolyzer with a triangular flow channel, aiming to reduce membrane electrode hydrogen adhesion and improve electrolyzer performance by optimizing the flow channel structure. Background Art

[0002] As the global demand for clean energy continues to grow, hydrogen energy, as an efficient and clean energy carrier, has received widespread attention. As an efficient water electrolysis hydrogen production device, PEM electrolyzer has the advantages of fast start-up, rapid response, and high current density, and plays an important role in the hydrogen energy industry.

[0003] During the operation of PEM electrolyzers, hydrogen adhesion on the membrane electrode is a key issue. Hydrogen adhesion will hinder proton conduction and reduce electrode reaction activity, thereby affecting the performance of the electrolyzer and hydrogen production efficiency. Traditional PEM electrolyzer flow channels are mostly rectangular or circular in shape, which have certain limitations in promoting gas discharge and reducing hydrogen adhesion. Therefore, it is of great significance to develop a new flow channel structure to improve this situation. Summary of the invention

[0004] The object of the present invention is to provide a PEM electrolyzer with a triangular flow channel, which increases fluid disturbance and improves gas discharge through the unique structure of the triangular flow channel, effectively reduces the adhesion of hydrogen on the membrane electrode, and thus improves the performance of the electrolyzer.

[0005] The PEM electrolyzer with triangular flow channels of the present invention comprises an anode plate, a cathode plate and a membrane electrode assembly located between the anode plate and the cathode plate, wherein the inner surfaces of the anode plate and the cathode plate are respectively provided with triangular flow channels.

[0006] The vertex angle of the triangular flow channel is 30° - 90°, preferably 45° - 60°. The depth of the flow channel is 0.5 - 5 mm, the width is 0.5 - 5 mm, and the spacing between the flow channels is 1 - 10 mm. The triangular flow channels can be arranged in parallel, staggered or other optimized arrangements to ensure that the electrolyte flows evenly in the flow channel and fully covers the membrane electrode surface.

[0007] The anode plate and cathode plate can be made of metal materials (such as stainless steel, titanium alloy, etc.) or graphite materials. Metal materials have good electrical conductivity and mechanical strength, while graphite materials have good chemical stability and corrosion resistance.

[0008] The membrane electrode assembly includes a proton exchange membrane, an anode catalyst layer and a cathode catalyst layer. The proton exchange membrane can be made of high-performance materials such as perfluorosulfonic acid membrane, which has high proton conductivity and good chemical stability. The anode catalyst layer can use catalysts such as iridium dioxide, and the cathode catalyst layer can use catalysts such as platinum or platinum alloy to improve the catalytic activity and efficiency of the electrolysis reaction.

[0009] The working principle of the PEM electrolyzer with triangular flow channels of the present invention is as follows: when the electrolyte (usually pure water or dilute alkaline solution) enters the triangular flow channel of the anode plate, an oxidation reaction occurs at the anode under the action of the electric field, and water molecules decompose to produce oxygen and protons, and the protons migrate to the cathode through the proton exchange membrane. At the cathode, protons combine with electrons to undergo a reduction reaction to generate hydrogen. Due to the special structure of the triangular flow channel, the electrolyte generates strong fluid disturbance when flowing in the flow channel, so that the gases (oxygen and hydrogen) generated by the reaction can quickly detach from the electrode surface and be discharged along the flow channel, effectively reducing the adhesion of hydrogen on the membrane electrode, improving the proton conduction efficiency and electrode reaction activity, and thus improving the overall performance of the electrolyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of the structure of a PEM electrolyzer; Among them: 1 – bipolar plate, 2 – sealing gasket, 3 – cathode diffusion layer, 4 – first electrode frame, 5 – membrane electrode assembly, 6 – second electrode frame, 7 – anode diffusion layer.

[0011] Figure 2 is a schematic diagram of the structure of the bipolar plate of a PEM electrolyzer; Where: 101 – triangular main flow channel of the bipolar plate.

[0012] Figure 3 Cross-sectional view of bipolar plates in a PEM electrolyzer Where: a - vertex angle, h - channel depth, w - channel width, d - channel spacing. DETAILED DESCRIPTION

[0013] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0014] Embodiment 1: Stainless steel is selected as the material of the anode plate and the cathode plate, and a triangular flow channel is machined on the inner surface of the anode plate and the cathode plate by mechanical processing. The vertex angle of the triangular flow channel is set to 45°, the flow channel depth is 1mm, the width is 1mm, the flow channel spacing is 2mm, and a parallel arrangement is adopted. In the membrane electrode assembly, the proton exchange membrane uses Nafion 117 perfluorosulfonic acid membrane, the anode catalyst layer uses iridium dioxide, and the cathode catalyst layer uses platinum. The anode plate, the membrane electrode assembly and the cathode plate are assembled into an electrolyzer in sequence, and a cooling channel is set on the outside of the anode plate and the cathode plate. A potassium hydroxide solution with a concentration of 0.5mol / L is injected into the electrolyzer as an electrolyte, and a DC voltage of 2V is applied for electrolysis experiments. The experimental results show that compared with the traditional rectangular flow channel electrolyzer, the electrolyzer of the present invention has a 15% increase in current density at the same voltage, a 25% decrease in the amount of hydrogen attached to the membrane electrode, and a significant improvement in the hydrogen production efficiency of the electrolyzer.

[0015] Embodiment 2: The anode plate and cathode plate are made of graphite material, and the triangular flow channel is processed by chemical etching process. The vertex angle of the triangular flow channel is 60°, the flow channel depth is 2mm, the width is 2mm, the flow channel spacing is 3mm, and the staggered arrangement is adopted. The proton exchange membrane in the membrane electrode assembly is Nafion 212, the anode catalyst is a composite catalyst of iridium dioxide and ruthenium oxide, and the cathode catalyst is platinum-cobalt alloy. After assembling the electrolyzer, pure water is used as the electrolyte and electrolysis is carried out at a voltage of 1.8V. After testing, the hydrogen purity of the electrolyzer is 5% higher than that of the traditional electrolyzer, the energy conversion efficiency of the electrolyzer is increased by 10%, and the performance is stable during long-term operation, and the membrane electrode does not show obvious performance degradation caused by hydrogen adhesion.

[0016] Embodiment 3: The anode plate and cathode plate are made of titanium alloy, and the plates with triangular flow channels are manufactured using 3D printing technology. The vertex angle of the triangular flow channel is 50°, the flow channel depth is 3mm, the width is 3mm, the flow channel spacing is 5mm, and a special mixed arrangement (combining the characteristics of parallel and staggered) is adopted. The membrane electrode assembly adopts a new high-performance proton exchange membrane, the anode catalyst is modified iridium dioxide, and the cathode catalyst is nanostructured platinum. The electrolyzer is operated at a voltage of 2.2V with a 0.3mol / L sodium hydroxide solution as the electrolyte. Experiments have found that the electrolyzer of the present invention can work stably at a high current density (3A / cm²), the membrane electrode hydrogen attachment amount is reduced by more than 30% compared with the traditional electrolyzer, and the hydrogen production rate is increased by 20%. At the same time, due to the optimization of the flow channel structure and the reasonable selection of materials, the overall service life of the electrolyzer is expected to be extended by 30%.

Claims

1. A PEM electrolyzer having a triangular flow channel, characterized in that: The invention comprises an anode plate, a cathode plate and a membrane electrode assembly located between the anode plate and the cathode plate. The inner surfaces of the anode plate and the cathode plate are respectively provided with triangular flow channels.

2. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: The vertex angle of the triangular flow channel is 30°-90°.

3. The PEM electrolyzer with triangular flow channels according to claim 2, characterized in that: The vertex angle of the triangular flow channel is preferably 45° - 60°.

4. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: The depth of the triangular flow channel is 0.5-5 mm, the width is 0.5-5 mm, and the spacing between the flow channels is 1-10 mm.

5. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: The triangular flow channels are arranged in parallel, staggered or in other optimized arrangements.

6. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: The anode plate and the cathode plate are made of metal material or graphite material.

7. The PEM electrolyzer with triangular flow channels according to claim 6, characterized in that: The metal material includes stainless steel and titanium alloy.

8. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: Cooling channels are arranged on the outer sides of the anode plate and the cathode plate.

9. The PEM electrolyzer with triangular flow channels according to claim 1, characterized in that: The membrane electrode assembly includes a proton exchange membrane, an anode catalyst layer and a cathode catalyst layer.

10. The PEM electrolyzer with triangular flow channels according to claim 9, characterized in that: The proton exchange membrane is a perfluorosulfonic acid membrane, the anode catalyst layer is iridium dioxide, and the cathode catalyst layer is platinum or a platinum alloy.

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