PEM bipolar plate

Abstract

The PEM bipolar plate comprises a substrate, a reactant inlet, a product outlet, a convex ridge and two groups of plugging blocks, the reactant inlet and the product outlet are formed in one surface A of the substrate in a penetrating manner; the reactant inlet and the product outlet are respectively positioned at two ends of the substrate; the plurality of convex ridges and the two groups of blocking blocks are integrally formed and arranged on the surface A of the base plate, the plurality of convex ridges are located in the middle of the base plate, and a groove area defined by the plurality of convex ridges is a middle flow channel; the group of blocking blocks are arranged between the reactant inlet and the middle flow channel, and a groove area formed by the blocking blocks and the substrate is an inlet flow channel; the other group of blocking blocks are arranged between the middle flow channel and the product outlet, and a groove area formed by the blocking blocks and the base plate is an outlet flow channel; the distribution uniformity of reactant-water in the middle flow channel is improved, and gas is prevented from being accumulated at the outlet, so that the distribution uniformity of heat transfer substances and heat is improved, and the performance of the electrolytic cell is improved.

Description

Technical Field

[0001] The invention belongs to the field of PEM water electrolysis hydrogen production, and specifically relates to a PEM bipolar plate. Background Art

[0002] PEM (Proton Exchange Membrane) electrolysis hydrogen technology is a highly efficient water electrolysis technology, mainly used to decompose water into hydrogen and oxygen. The core components of the PEM electrolyzer include membrane electrode, gas diffusion layer and bipolar plate; the membrane electrode is located in the middle, the two bipolar plates are located on both sides of the membrane electrode, the gas diffusion layer is located between the corresponding bipolar plate and the membrane electrode, and the membrane electrode includes a membrane and a catalyst layer coated on the membrane.

[0003] The function of the bipolar plate is to provide the reactant water for the catalyst layer, provide mechanical support for the membrane electrode, and provide a flow channel for water and products. The structure of the bipolar plate will affect the utilization efficiency of the catalyst and the uniformity of water distribution. The current structural design of the bipolar plate has poor uniformity in material distribution and heat distribution, resulting in low electrolyzer performance. In addition, in the field of PEM electrolyzers, there is little research on bipolar plate coatings, and most of the coatings are made of precious metals, which are not only costly, but also have poor conductivity and insufficient water supply, resulting in low electrolyzer performance. Summary of the invention

[0004] In view of this, the present invention provides a PEM bipolar plate that can improve the uniformity of the distribution of the reactant water in the middle flow channel and avoid gas accumulation at the outlet, thereby improving the uniformity of heat transfer material and heat distribution and improving the performance of the electrolyzer.

[0005] The present invention is achieved through the following technical solutions:

[0006] A PEM bipolar plate includes a substrate, a reactant inlet, a product outlet, a ridge and two groups of blocking blocks;

[0007] The peripheral components include a gas diffusion layer and a membrane electrode; the membrane electrode, the gas diffusion layer and the bipolar plate are arranged from the inside to the outside;

[0008] The reactant inlet and the product outlet are arranged on a surface A of the substrate; the reactant inlet and the product outlet are respectively located at two ends of the substrate;

[0009] A plurality of ridges and two groups of blocking blocks are integrally formed and arranged on the surface A of the substrate;

[0010] A plurality of ridges are located in the middle of the substrate, and a groove area surrounded by the plurality of ridges is a middle flow channel;

[0011] A group of blocking blocks are arranged between the reactant inlet and the middle flow channel, and the groove area formed by the blocking blocks and the substrate is the inlet flow channel;

[0012] Another group of blocking blocks is arranged between the middle flow channel and the product outlet, and the groove area formed by the blocking blocks and the substrate is the outlet flow channel;

[0013] Water enters the bipolar plate from the reactant inlet, and the blockage of the inlet flow channel is used to disturb the water so that it diffuses toward the membrane electrode;

[0014] The ridges are used to diffuse the water in the middle flow channel toward the membrane electrode;

[0015] The oxygen generated after the reaction is discharged from the product outlet along with the water. When the oxygen passes through the outlet flow channel, the block in the outlet flow channel is used to break the oxygen bubbles.

[0016] Furthermore, a conductive protective coating is provided on the bipolar plate.

[0017] Furthermore, the conductive protective coating is a titanium carbide coating.

[0018] Furthermore, a hydrophilic coating is provided on the conductive protective coating on the inner bottom surfaces of the inlet flow channel, the middle flow channel and the outlet flow channel.

[0019] Furthermore, the hydrophilic coating is a silicon dioxide coating.

[0020] Furthermore, the reactant inlet and the product outlet are arranged diagonally.

[0021] Furthermore, each group of blocks includes more than one block, and the block is projected on the surface A of the substrate into one or more of a square, a circle, a triangle, a trapezoid, an ellipse, a circular segment or other polygons; when there are multiple blocks, the blocks can be arranged in parallel or staggered and evenly arranged;

[0022] The maximum length and the maximum width of each block are not greater than the width of the middle flow channel, and the height of the block is consistent with the height of the ridge.

[0023] Furthermore, the hydrophilic coating and the conductive protective coating can be coated by any one of chemical vapor deposition, physical vapor deposition or plasma spraying.

[0024] Furthermore, the middle flow channel is any one or a combination of serpentine flow channel, parallel flow channel, bionic flow channel, wavy flow channel or interdigital flow channel.

[0025] Furthermore, a protruding frame is arranged around the outer periphery of the surface A of the substrate, and a sealing ring is arranged on the frame.

[0026] Beneficial effects:

[0027] (1) The present invention provides a PEM bipolar plate. On the one hand, a group of blocks are arranged between the reactant inlet and the middle flow channel. When water flows through the inlet flow channel, the blocks will disturb the water, promote the mass transfer of water toward the membrane electrode, and finally reach the reaction interface of the catalyst layer to participate in the electrochemical reaction. On the other hand, another group of blocks is arranged between the middle flow channel and the product outlet. When the oxygen in the product passes through the outlet flow channel, the blocks will break up the oxygen bubbles, which is conducive to the rapid discharge of oxygen from the product outlet along with the flow of water; thereby improving the uniformity of heat transfer material and heat distribution and improving the performance of the electrolyzer.

[0028] (2) The conductive protective coating of the present invention adopts titanium carbide coating, which will not affect other peripheral components such as membrane electrode, but also helps to extend the service life of the electrolytic cell and improve the conductivity and operation stability of the bipolar plate. In addition, the conductive protective coating adopts non-precious metal, which can reduce the processing cost of the bipolar plate.

[0029] (3) The hydrophilic coating of the present invention can retain water in the reaction zone, thereby continuously providing water to peripheral components, ensuring sufficient water supply, promoting the full progress of the reaction, and improving the performance of the electrolytic cell.

[0030] (4) The hydrophilic coating of the present invention uses silicon dioxide. On the one hand, the silicon dioxide coating has low cost, and on the other hand, it has hydrophilicity and does not affect other components. It is suitable for use on bipolar plates to improve the performance of electrolytic cells.

[0031] (5) The reactant inlet and product outlet of the present invention are arranged diagonally, which is beneficial to improving the distribution uniformity of the reactants.

[0032] (6) The invention is provided with a sealing ring to prevent leakage of reactants and products.

[0033] In summary, the present invention optimizes the structure of the bipolar plate, and adopts a non-precious metal conductive protective coating and applies a hydrophilic coating, which not only improves the ability of heat transfer materials and heat distribution uniformity, but also improves the performance of the electrolytic cell, extends its life, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a front view of a PEM bipolar plate structure;

[0035] Figure 2 It is an axonometric view of the PEM bipolar plate structure;

[0036] Among them, 1-reactant inlet, 2-product outlet, 3-ridge, 4-middle flow channel, 5-sealing ring, 6-block, 7-conductive protective coating, 8-hydrophilic coating, 9-inlet flow channel, 10-outlet flow channel. DETAILED DESCRIPTION

[0037] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0038] This embodiment provides a PEM bipolar plate, see the attached Figure 1 and 2 , comprising a substrate, a reactant inlet 1, a product outlet 2, a ridge 3 and two groups of blocking blocks 6;

[0039] The peripheral components include a gas diffusion layer and a membrane electrode; the membrane electrode, the gas diffusion layer and the bipolar plate are arranged from the inside to the outside;

[0040] The reactant inlet 1 and the product outlet 2 are arranged on a surface A of the substrate; the reactant inlet 1 and the product outlet 2 are respectively located at two ends of the substrate;

[0041] A plurality of ridges 3 and two groups of blocking blocks 6 are integrally formed and arranged on the surface A of the substrate;

[0042] A plurality of ridges 3 are located in the middle of the substrate, and a groove area surrounded by the plurality of ridges 3 is a middle flow channel 4;

[0043] A group of blocking blocks 6 is arranged between the reactant inlet 1 and the intermediate flow channel 4, and the groove area formed by the blocking blocks 6 and the substrate is the inlet flow channel 9;

[0044] Another group of blocking blocks 6 is arranged between the middle flow channel 4 and the product outlet 2, and the groove area formed by the blocking blocks 6 and the substrate is the outlet flow channel 10;

[0045] Water enters the bipolar plate from the reactant inlet 1, and the block 6 of the inlet flow channel 9 is used to disturb the water so that the water diffuses toward the membrane electrode;

[0046] The ridge 3 is used to diffuse the water in the middle flow channel 4 toward the membrane electrode;

[0047] The oxygen generated after the reaction is discharged from the product outlet 2 along with the water. When the oxygen passes through the outlet flow channel 10, the block 6 in the outlet flow channel 10 is used to break the oxygen bubbles.

[0048] A PEM bipolar plate provided in this embodiment has, on the one hand, a group of blocks 6 arranged between the reactant inlet 1 and the intermediate flow channel 4. When water flows through the inlet flow channel 9, the blocks 6 disturb the water, thereby promoting the mass transfer of water toward the membrane electrode, and finally reaching the reaction interface of the catalyst layer to participate in the electrochemical reaction. On the other hand, another group of blocks 6 is arranged between the intermediate flow channel 4 and the product outlet 2. When the oxygen in the product passes through the outlet flow channel 10, the blocks 6 break the oxygen bubbles, which is beneficial for the rapid discharge of oxygen from the product outlet 2 along with the flow of water; thereby improving the uniformity of heat transfer material and heat distribution, and improving the performance of the electrolyzer.

[0049] In one embodiment, a conductive protective coating 7 is provided on the bipolar plate. The conductive protective coating 7 is a coating that will not affect other peripheral components such as the membrane electrode, and is used for conducting electricity and protecting the substrate and all components of the surface A.

[0050] Furthermore, the conductive protective coating 7 is a titanium carbide coating with a coating thickness of 50nm to 100nm. The titanium carbide coating will not affect other peripheral components such as the membrane electrode, but is also beneficial to extending the service life of the electrolytic cell and improving the conductivity and operating stability of the bipolar plate. Moreover, the conductive protective coating 7 uses non-precious metals, which can reduce the processing cost of the bipolar plate.

[0051] In one embodiment, a hydrophilic coating 8 is provided on the conductive protective coating 7 on the inner bottom surface of the inlet flow channel 9, the middle flow channel 4 and the outlet flow channel 10. The hydrophilic coating 8 is a coating that will not affect other peripheral components such as the membrane electrode, and is used to retain water in the reaction zone, thereby continuously providing water to the membrane electrode, ensuring sufficient water supply, promoting the full reaction, and improving the performance of the electrolytic cell.

[0052] Furthermore, the hydrophilic coating 8 is a silicon dioxide coating with a coating thickness of 5nm to 50nm. The silicon dioxide coating is low in cost and has hydrophilicity without affecting other components. It is suitable for use on bipolar plates to improve the performance of electrolytic cells.

[0053] In one embodiment, each group of blocking blocks 6 includes more than one blocking block 6, and the blocking blocks 6 are projected on the surface A of the substrate into one or more of a square, a circle, a triangle, a trapezoid, an ellipse, a circular segment or other polygons; when there are multiple blocking blocks 6, the blocking blocks 6 can be arranged in parallel or staggered and evenly arranged;

[0054] Furthermore, the maximum length and the maximum width of each block 6 are not greater than the width of the middle flow channel 4, and the height of the block 6 is consistent with the height of the ridge 3;

[0055] In one embodiment, the reactant inlet 1 and the product outlet 2 are arranged diagonally, which is beneficial to improving the uniformity of water distribution.

[0056] In one embodiment, the hydrophilic coating 8 and the conductive protective coating 7 can be coated by any one of chemical vapor deposition, physical vapor deposition or plasma spraying;

[0057] In one embodiment, the middle flow channel 4 is any one or a combination of a serpentine flow channel, a parallel flow channel, a bionic flow channel, a wavy flow channel or an interdigitated flow channel.

[0058] In one embodiment, a protruding frame is disposed around the outer periphery of the surface A of the substrate, and a sealing ring 5 is disposed on the frame to prevent backflow and product leakage.

[0059] Working principle:

[0060] A group of blocks 6 are arranged between the reactant inlet 1 and the middle flow channel 4. When water passes through the group of blocks 6, the blocks 6 will disturb the water, promote the mass transfer of water toward the membrane electrode, and finally reach the reaction interface of the catalyst layer to participate in the electrochemical reaction and finally generate oxygen and hydrogen;

[0061] The ridge 3 in the middle flow channel is used to diffuse the water in the middle flow channel 4 toward the membrane electrode;

[0062] Another group of blocks 6 is provided between the middle flow channel 4 and the product outlet 2. When the oxygen in the product passes through the group of blocks 6, the blocks 6 break the oxygen bubbles, which is conducive to the rapid discharge of oxygen from the product outlet 2 along with the flow of water, and the hydrogen is discharged from the outlet on the other side of the electrolyzer (not shown in the figure).

[0063] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A PEM bipolar plate, characterized in that: It includes a base plate, a reactant inlet, a product outlet, a ridge and two sets of blocking blocks; The peripheral components include a gas diffusion layer and a membrane electrode; the membrane electrode, the gas diffusion layer and the bipolar plate are arranged from the inside to the outside; The reactant inlet and the product outlet are arranged on a surface A of the substrate; the reactant inlet and the product outlet are respectively located at two ends of the substrate; A plurality of ridges and two groups of blocking blocks are integrally formed and arranged on the surface A of the substrate; A plurality of ridges are located in the middle of the substrate, and a groove area surrounded by the plurality of ridges is a middle flow channel; A group of blocking blocks are arranged between the reactant inlet and the middle flow channel, and the groove area formed by the blocking blocks and the substrate is the inlet flow channel; Another group of blocking blocks is arranged between the middle flow channel and the product outlet, and the groove area formed by the blocking blocks and the substrate is the outlet flow channel; Water enters the bipolar plate from the reactant inlet, and the blockage of the inlet flow channel is used to disturb the water so that it diffuses toward the membrane electrode; The ridges are used to diffuse the water in the middle flow channel toward the membrane electrode; The oxygen generated after the reaction is discharged from the product outlet along with the water. When the oxygen passes through the outlet flow channel, the block in the outlet flow channel is used to break the oxygen bubbles.

2. A PEM bipolar plate as claimed in claim 1, characterized in that: A conductive protective coating is provided on the bipolar plate.

3. A PEM bipolar plate as claimed in claim 2, characterized in that: The conductive protective coating is a titanium carbide coating.

4. A PEM bipolar plate as claimed in claim 2 or 3, characterized in that: A hydrophilic coating is arranged on the conductive protective coating on the inner bottom surfaces of the inlet flow channel, the middle flow channel and the outlet flow channel.

5. A PEM bipolar plate as claimed in claim 4, characterized in that: The hydrophilic coating is a silica coating.

6. A PEM bipolar plate as claimed in claim 1, characterized in that: The reactant inlet and product outlet are arranged diagonally.

7. A PEM bipolar plate as claimed in claim 1, characterized in that: Each group of blocks includes more than one block, and the block is projected on the surface A of the substrate into one or more of a square, a circle, a triangle, a trapezoid, an ellipse, a circular segment or other polygons; when there are multiple blocks, the blocks can be arranged in parallel or staggered and evenly arranged; The maximum length and the maximum width of each block are not greater than the width of the middle flow channel, and the height of the block is consistent with the height of the ridge.

8. A PEM bipolar plate as claimed in claim 4, characterized in that: The hydrophilic coating and the conductive protective coating can be coated by any method including chemical vapor deposition, physical vapor deposition or plasma spraying.

9. A PEM bipolar plate as claimed in claim 1, characterized in that: The middle flow channel is any one of a serpentine flow channel, a parallel flow channel, a bionic flow channel, a wave flow channel or an interdigital flow channel or a combination of several of them.

10. A PEM bipolar plate as claimed in claim 1, characterized in that: A protruding frame is arranged around the outer periphery of the surface A of the substrate, and a sealing ring is arranged on the frame.

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