PEM electrolytic bath for realizing ordered bubble regulation and control and electrolysis process

Abstract

The invention provides a PEM electrolytic cell for realizing ordered bubble regulation and an electrolysis process. The PEM electrolytic cell comprises a proton exchange membrane, and a catalyst layer, a straight-through hole porous transmission layer containing a flow baffle, an electrode plate and an end plate which are sequentially and symmetrically arranged on the proton exchange membrane, wherein the porous transmission layer comprises three layers of structures: rectangular grooves are uniformly formed in the first layer, the flow baffles are arranged on the peripheries of the short edges of the grooves, and ribs are arranged on the peripheries of the long edges of the grooves; straight through holes are uniformly formed in the second layer; rectangular grooves are uniformly formed in the third layer, flow baffles are arranged on the peripheries of the short edges of the grooves, and ribs are arranged on the peripheries of the long edges of the grooves. According to the electrolytic cell, bubble sequenced flowing can be achieved, the bubble removal frequency reaches up to 50 Hz, the temperature of a catalytic layer of the electrolytic cell is rapidly reduced within milliseconds, and the problems of bubble accumulation and local overheating are thoroughly solved. The electrolytic cell can stably operate under the high-current-density operation condition of 1-10 A / cm < 2 >, and the total energy consumption is reduced by 8.91%-30.92%.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production, and in particular to a PEM electrolyzer and electrolysis process for achieving ordered bubble control. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis technology, as a key bridge connecting fluctuating renewable energy and green hydrogen energy, has become a highly promising technological route in the field of green hydrogen production due to its outstanding advantages such as high efficiency, fast dynamic response, high purity of product gas, and compact structure. Reducing the levelized cost of hydrogen production is the core driving force for its large-scale commercialization, and increasing the operating current density is one of the most direct and effective engineering approaches to achieve this goal, meaning that higher hydrogen production capacity can be obtained with the same equipment investment.

[0003] However, as current density increases, the intense electrochemical reactions per unit electrode area generate a large amount of hydrogen and oxygen bubbles. In traditional PEM electrolyzers, the porous transport layer (typically made of sintered titanium, titanium mesh, or titanium with a through-pore structure), which performs functions such as gas extraction, electron conduction, heat transfer, and mass transfer, gradually reveals its limitations under high gas production rates due to its inherent pore structure and surface characteristics. Bubbles tend to remain, merge, and accumulate at the three-dimensional interface between the porous transport layer and the catalyst layer, forming dynamic gas films or gas pockets. This interfacial bubble coverage directly obscures some catalytic active sites, leading to a significant loss of electrochemical active surface area and causing uneven local current density distribution and intensified concentration polarization.

[0004] Furthermore, the prolonged retention of bubbles severely hinders the efficient transport of protons, electrons, and water at the reaction interface, making it difficult for the ohmic heat generated during the reaction to dissipate quickly and uniformly through liquid water or the solid framework. The continuous accumulation of localized heat causes localized hot spots in the membrane electrode assembly, particularly the temperature-sensitive proton exchange membrane. This non-uniform thermal stress accelerates the degradation of sulfonic acid groups in the proton exchange membrane, the breakage of polymer chains, and the decline in mechanical properties, while also exacerbating catalyst instability and shedding. Ultimately, these coupling effects lead to irreversible performance degradation and a significantly shortened lifespan of the electrolyzer, ultimately offsetting the potential cost advantages of increasing current density from a total life-cycle cost perspective.

[0005] Therefore, breaking through the bottleneck of gas-liquid transport in traditional porous transport layers at high current densities and constructing an innovative structure that enables rapid bubble detachment and discharge, and ensures efficient mass transfer and uniform heat dissipation at the reaction interface has become the challenge and core research direction for PEM water electrolysis technology to develop towards higher current densities, lower system costs and longer service life. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a PEM electrolyzer for achieving ordered bubble control. This electrolyzer can realize ordered bubble flow, achieve a bubble removal frequency of up to 50Hz, and rapidly cool down the temperature of the catalyst layer within milliseconds, completely solving the problems of bubble accumulation and local overheating, and can achieve an efficiency of 1~10 A / cm 2 It operates stably under high current density operating conditions, and the total energy consumption (including external circuit energy consumption) is reduced by 8.91% to 30.92% under the above current density operating conditions.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a PEM electrolyzer for achieving ordered bubble control, the PEM electrolyzer comprising a proton exchange membrane, and a catalyst layer, a porous transport layer with baffles and through holes, an electrode plate and an end plate arranged symmetrically in sequence from the proton exchange membrane;

[0009] The porous transmission layer with baffles and through holes has a three-layer structure: the first layer is uniformly provided with rectangular grooves, the short side of which is a baffle and the long side of which is a rib; the second layer is uniformly provided with through holes; the third layer is uniformly provided with rectangular grooves, the short side of which is a baffle and the long side of which is a rib.

[0010] The groove has a length of 0.1mm~2.0mm, a width of 0.02mm~2mm, and a depth of 0.02mm~2mm; the diameter of the through hole is 0.02mm~2mm, and the width of the gas collection area and the liquid phase distribution area is 0.05cm~0.5cm; the anode of the catalyst layer uses iridium oxide catalyst, and the cathode uses platinum carbon catalyst; the electrode plate is made of titanium metal, and the end plate is made of aluminum; the proton exchange membrane is a 0.1mm~3mm Nafion membrane.

[0011] The proton exchange membrane (PEM) electrolyzer provided by this invention includes a baffle plate with through-holes and a porous transport layer. This eliminates the interface transfer problem between the flow channel and the porous transport layer, completely intercepting the inlet liquid and introducing it to the surface of the catalyst layer, allowing bubbles to be immediately removed upon formation on the catalyst layer surface. This electrolyzer enables ordered bubble flow, achieving a bubble removal frequency of up to 50Hz. The temperature of the electrolyzer's catalyst layer rapidly cools down within milliseconds, completely solving the problems of bubble accumulation and localized overheating.

[0012] As a preferred embodiment of the present invention, the end plate is provided with a liquid inlet and a liquid outlet, and the electrode plate is provided with a liquid inlet and a liquid outlet corresponding to the end plate.

[0013] As a preferred embodiment of the present invention, all three layers of the porous transmission layer containing the baffle through-hole are made of titanium.

[0014] As a preferred embodiment of the present invention, the ribs of the first layer and the ribs of the third layer overlap in the direction perpendicular to the catalyst layer.

[0015] As a preferred technical solution of the present invention, two adjacent ribs of the first layer form a channel, and a channel has a plurality of grooves, with two adjacent grooves separated by a baffle plate.

[0016] As a preferred embodiment of the present invention, the length of the groove in the first and third layers is the same as the length of the two through holes in the second layer.

[0017] As a preferred embodiment of the present invention, the gap between the through holes in the second layer is the width of a baffle plate.

[0018] As a preferred embodiment of the present invention, the porous transport layer with baffles and through holes is provided with a liquid distribution area, a liquid deflection area and a bubble collection area in sequence along the liquid flow direction; the liquid distribution area corresponds to the liquid inlet of the electrode plate, the liquid deflection area is a region with grooves and through holes, and the bubble collection area corresponds to the liquid outlet of the electrode plate.

[0019] In a second aspect, the present invention provides a PEM electrolysis process for achieving ordered bubble control, wherein the PEM electrolysis process employs the PEM electrolysis cell as described in the first aspect.

[0020] As a preferred technical solution of the present invention, the PEM electrolysis process includes the following steps: after the liquid enters the liquid distribution area through the liquid inlet, it is evenly distributed to each channel. Under the interception of the third layer baffle, it passes through the straight hole of the second layer to reach the groove of the first layer and then enters the catalyst layer to carry out the water electrolysis reaction. Bubbles are generated at the interface between the groove of the first layer and the catalyst layer. Then the liquid carries the bubbles back to the third layer through the straight hole. Under the interception of the adjacent row of baffles, it passes through the straight hole again to reach the catalyst layer, and so on, to achieve the orderly arrangement of bubbles.

[0021] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0022] (1) The electrolyzer can achieve ordered flow of bubbles, and can control the gas content and temperature of the catalyst layer interface in microseconds, so that the bubbles generated are removed immediately, and the bubble removal frequency is as high as 50 Hz. The temperature of the catalyst layer of the electrolyzer drops rapidly within milliseconds, which completely solves the problems of bubble accumulation and local overheating.

[0023] (2) The electrolytic cell can operate at 1~10 A / cm 2 Stable operation under high current density operating conditions, reducing total electrolysis energy consumption (including external circuit energy consumption) by 8.91%~30.92%. Attached Figure Description

[0024] Figure 1 This is a model diagram of the PEM electrolyzer in Example 2;

[0025] In the figure: 1-Porous transport layer with baffles and through holes; 2-Proton exchange membrane (PEM); 3-Catalyst layer; 4-Electrode plate; 5-End plate; 6-Anode inlet; 7-Anode outlet; 8-Cathode outlet; 9-Cathode outlet.

[0026] Figure 2 This is a model diagram of the porous transmission layer with baffles and through holes in Example 2;

[0027] In the diagram: 1-first layer, 2-second layer, 3-third layer, 4-liquid distribution area, 5-baffle through hole area, 6-bubble collection area, 7-baffle, 8-groove, 9-rib, 10-through hole;

[0028] Figure 3 This is a physical image of the perforated porous transmission layer with straight through holes in the baffle plate of Example 2;

[0029] Figure 4 This applies to the gas-liquid flow morphology characteristics of Example 1;

[0030] Figure 5 This is a partial experimental diagram of ordered bubble flow from Example 1;

[0031] Figure 6 The comparison is between ordered bubble flow in Application Example 1 and disordered bubble flow in Application Example 2.

[0032] Figure 7 Comparative Example 1 is sintered titanium porous media + titanium mesh;

[0033] Figure 8 This is an application example 1, showing the ratio of current density to energy consumption reduction. Detailed Implementation

[0034] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0035] It should be clarified that any use of the process provided in the embodiments of the present invention or any substitution or change of conventional data falls within the protection and disclosure scope of the present invention.

[0036] Example 1

[0037] This embodiment provides a PEM electrolyzer for achieving ordered bubble control. The PEM electrolyzer includes a proton exchange membrane, and a catalyst layer, a porous transport layer with baffles and through holes, an electrode plate, and an end plate arranged symmetrically in sequence from the proton exchange membrane.

[0038] The porous transmission layer with baffles and through holes has a three-layer structure: the first layer is uniformly provided with rectangular grooves, the short side of the groove is a baffle, and the long side of the groove is a rib; the second layer is uniformly provided with through holes; the third layer is uniformly provided with rectangular grooves, the short side of the groove is a baffle, and the long side of the groove is a rib.

[0039] The groove has a length of 0.6 mm, a width of 0.2 mm, and a depth of 0.5 mm; the through hole has a diameter of 0.2 mm, and the gas collection area and liquid phase distribution area have a width of 0.5 cm; the anode of the catalyst layer uses iridium oxide catalyst, and the cathode uses platinum carbon catalyst; the electrode plate is made of titanium metal, and the end plate is made of aluminum; the proton exchange membrane is a 1 mm thick Nafion membrane.

[0040] Example 2

[0041] This embodiment provides a PEM electrolyzer for achieving ordered bubble control. The PEM electrolyzer includes a proton exchange membrane, and a catalyst layer, a porous transport layer with baffles and through holes, an electrode plate, and an end plate arranged symmetrically in sequence from the proton exchange membrane.

[0042] The end plates are respectively provided with liquid inlets and liquid outlets, and the electrode plates are provided with liquid inlets and liquid outlets corresponding to the end plates;

[0043] The porous transmission layer with baffles and through holes has a three-layer structure (all made of titanium): the first layer is uniformly provided with rectangular grooves, the short side of the groove is a baffle, and the long side of the groove is a rib; the second layer is uniformly provided with through holes; the third layer is uniformly provided with rectangular grooves, the short side of the groove is a baffle, and the long side of the groove is a rib.

[0044] The ribs of the first layer and the ribs of the third layer coincide in the direction perpendicular to the catalyst layer. Two adjacent ribs of the first layer form a channel, and a channel has several grooves. Two adjacent grooves are separated by baffles. The length of the grooves in the first and third layers is the length of two through holes in the second layer. The gap between the through holes in the second layer is the width of a baffle. The porous transport layer containing baffles and through holes is provided with a liquid distribution area, a liquid deflection area and a bubble collection area in sequence along the liquid flow direction. The liquid distribution area corresponds to the liquid inlet of the electrode plate. The liquid deflection area is a region with grooves and through holes. The bubble collection area corresponds to the liquid outlet of the electrode plate.

[0045] The groove is 0.8 mm long, 0.9 mm wide, and 2 mm deep; the through hole has a diameter of 1 mm, and the gas collection area and liquid phase distribution area have a width of 0.3 cm; the anode of the catalyst layer uses iridium oxide catalyst, and the cathode uses platinum carbon catalyst; the electrode plate is made of titanium metal, and the end plate is made of aluminum; the proton exchange membrane is a 1 mm thick Nafion membrane.

[0046] Comparative Example 1

[0047] This comparative example provides a PEM electrolyzer for achieving ordered bubble control. The only difference between the PEM electrolyzer and Example 2 is that a sintered titanium porous medium and a titanium mesh are used instead of a porous transport layer with baffles and through holes. All other aspects are the same as in Example 2.

[0048] Application Example 1

[0049] This embodiment provides a PEM electrolysis process for achieving ordered bubble control, wherein the PEM electrolysis process uses the PEM electrolysis cell described in Embodiment 2;

[0050] The PEM electrolysis process includes the following steps: After entering the liquid distribution area through the liquid inlet, the liquid is evenly distributed to each channel. Under the interception of the third layer baffle, it passes through the straight hole of the second layer to reach the groove of the first layer and then enters the catalyst layer to carry out the water electrolysis reaction. Bubbles are generated at the interface between the groove of the first layer and the catalyst layer. Then, the liquid carries the bubbles back to the third layer through the straight hole. Under the interception of the adjacent row of baffles, it passes through the straight hole again to reach the catalyst layer, and so on, to achieve the orderly arrangement of bubbles.

[0051] Application Example 2

[0052] This comparative example provides a PEM electrolysis process for achieving ordered bubble control. The PEM electrolysis process uses the PEM electrolyzer described in Comparative Example 1, and other operating conditions are consistent with Application Example 1.

[0053] Performance testing

[0054] The limiting current density tests were performed on the PEM electrolysis processes provided in the examples and comparative examples, and the results are shown in Table 1.

[0055] Table 1

[0056]

[0057] Based on Table 1 Figure 1 As can be seen, the PEM electrolyzer includes a porous transport layer with baffles and through-holes, a proton exchange membrane (PEM), a catalyst, electrode plates, end plates, an anode inlet, an anode outlet, a cathode outlet, and a cathode outlet, with insulating material separating the electrode plates and end plates. Its core innovative structure is the porous transport layer with baffles and through-holes, such as... Figure 2 As shown, this porous transport layer with baffles and through holes has baffles, through holes, ribs, grooves, a liquid distribution area, a baffle through hole area, and a bubble collection area. Figure 3This is a physical diagram of a porous transport layer with baffles and through-holes. Two adjacent ribs form a channel, which contains several baffles and grooves. Two ribs and two baffles form a groove. After entering the distribution zone, the inlet liquid is evenly distributed to each channel. Under the interception effect of the baffles, it enters the catalyst layer through the through-holes, increasing the liquid velocity in the catalyst layer by 13.60 to 17.25 times. This enhances the shearing effect of the fluid on the bubbles, causing the bubbles to rapidly detach into discrete bubbles within 0.02 seconds. The bubbles flow within the channels, and their flow pattern is constrained by the regular baffles and ribs, forming an orderly arrangement. The experimental operating current density is 2 A / cm². 2 The inlet liquid flow rate was 145 mL / min. High-speed camera observation of bubble flow in the porous media layer showed that the bubbles flowed orderly along the channels. The time from the catalytic layer to the surface between the porous transport layer and the electrode plate was less than 0.001 seconds. A partial experimental view is shown below. Figure 5 As shown. A schematic diagram of the overall ordered bubbles is shown below. Figure 6 As shown. Experiments have verified that this electrolytic cell operates at 10 A / cm. 2 It has already been able to operate stably for more than 10 days at current densities, and is expected to operate stably for even longer periods. In terms of performance, such as... Figure 8 As shown, the energy consumption of Application Example 1 is compared to Figure 7 In application example 2, energy consumption can be reduced by 8.91% to 30.92%.

[0058] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A PEM electrolyzer for achieving ordered bubble control, characterized in that, The PEM electrolyzer includes a proton exchange membrane, and a catalyst layer, a porous transport layer with baffles and through holes, an electrode plate, and an end plate arranged symmetrically in sequence from the proton exchange membrane. The porous transmission layer with baffles and through holes has a three-layer structure: the first layer is uniformly provided with rectangular grooves, the short side of which is a baffle and the long side of which is a rib; the second layer is uniformly provided with through holes; the third layer is uniformly provided with rectangular grooves, the short side of which is a baffle and the long side of which is a rib.

2. The PEM electrolytic cell according to claim 1, characterized in that, The end plates are respectively provided with liquid inlets and liquid outlets, and the electrode plates are provided with liquid inlets and liquid outlets corresponding to the end plates.

3. The PEM electrolytic cell according to claim 1 or 2, characterized in that, All three layers of the porous transmission layer containing the baffle and through-hole are made of titanium.

4. The PEM electrolytic cell according to any one of claims 1 to 3, characterized in that, The ribs of the first layer and the ribs of the third layer coincide in the direction perpendicular to the catalyst layer.

5. The PEM electrolytic cell according to any one of claims 1 to 4, characterized in that, The first layer has two adjacent ribs forming a channel, and the channel has several grooves. Two adjacent grooves are separated by a baffle plate.

6. The PEM electrolytic cell according to any one of claims 1 to 5, characterized in that, The length of the groove in the first and third layers is equal to three times the diameter of the through hole in the second layer.

7. The PEM electrolytic cell according to any one of claims 1 to 6, characterized in that, The gap between the through holes in the second layer is the width of a baffle plate.

8. The PEM electrolytic cell according to any one of claims 2 to 7, characterized in that, The porous transport layer with baffles and through holes is provided with a liquid distribution area, a liquid deflection area and a bubble collection area in sequence along the liquid flow direction; the liquid distribution area corresponds to the liquid inlet of the electrode plate, the liquid deflection area is a region with grooves and through holes, and the bubble collection area corresponds to the liquid outlet of the electrode plate.

9. A PEM electrolysis process for achieving ordered bubble control, characterized in that, The PEM electrolysis process uses the PEM electrolysis cell as described in any one of claims 1 to 8.

10. The PEM electrolysis process according to claim 9, characterized in that, The PEM electrolysis process includes the following steps: After entering the liquid distribution area through the liquid inlet, the liquid is evenly distributed to each channel. Under the interception of the third layer baffle, it passes through the straight hole of the second layer to reach the groove of the first layer and then enters the catalyst layer to carry out the water electrolysis reaction. Bubbles are generated at the interface between the groove of the first layer and the catalyst layer. Then, the liquid carries the bubbles back to the third layer through the straight hole. Under the interception of the adjacent row of baffles, it passes through the straight hole again to reach the catalyst layer, and so on, to achieve the orderly arrangement of bubbles.

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