System for performing electrochemical reaction

Abstract

A system for performing an electrochemical reaction, the system comprising at least one electrochemical reaction subsystem, wherein the electrochemical reaction subsystem comprises: a first electrode; a second electrode; and a microfluidic channel unit, which is located between the first electrode and the second electrode and is used for electrolyte solution circulation, sidewalls of the microfluidic channel unit facing the first and second electrodes being provided with microporous structures, and the microfluidic channel unit being configured to have rigidity that satisfies a predetermined condition, so as to avoid deformation of the microfluidic channel unit during an electrochemical reaction.

Description

Systems for performing electrochemical reactions Technical Field

[0001] Embodiments of the present invention relate generally to the field of electrochemistry, and more particularly to systems for performing electrochemical reactions. Background Art

[0002] Hydrogen production through water electrolysis is an important method for producing hydrogen. In conventional electrochemical systems, hydrogen and oxygen often form bubbles on the surfaces of the corresponding electrodes during water electrolysis, which can easily cause gas blockage, hindering the water electrolysis reaction and reducing hydrogen production efficiency. Furthermore, the generated hydrogen can cross the diaphragm and mix with oxygen, posing a potential explosion risk.

[0003] In summary, when performing water electrolysis, the disadvantages of conventional systems for performing electrochemical reactions are that gas blockage is easily present at the electrodes, hydrogen production efficiency is low, and there is a risk of hydrogen and oxygen mixing.

[0004] Summary of the Invention

[0005] In response to the above problems, the present invention provides a system for conducting electrochemical reactions, which can keep the microchannel unit from deforming when the electrode spacing is small during water electrolysis, avoid the occurrence of hydrogen and oxygen mixing, and significantly reduce the occurrence of gas blockage at the electrodes, thereby improving hydrogen production efficiency.

[0006] According to a first aspect of the present invention, a system for conducting an electrochemical reaction is provided, comprising at least one electrochemical reaction subsystem, wherein the electrochemical reaction subsystem comprises: a first electrode; a second electrode; and a microfluidic unit located between the first electrode and the second electrode for allowing an electrolyte to circulate, wherein the side walls of the microfluidic unit facing the first electrode and the second electrode have a microporous structure, and the microfluidic unit is configured to have a rigidity that meets predetermined conditions to avoid deformation of the microfluidic unit during the electrochemical reaction.

[0007] In some embodiments, the micro-fluidic channel unit has a plurality of flow channels, so that the electrolyte flowing into the first end of the micro-fluidic channel unit flows out from the second end of the micro-fluidic channel unit via the plurality of flow channels.

[0008] In some embodiments, the first end of the microfluidic channel unit is located above the second end of the microfluidic channel unit. In some embodiments, the flow channel is made of at least one of the following materials: metal, ceramic, and hard plastic.

[0009] In some embodiments, the microfluidic channel unit includes: a fluid guide plate; and a porous membrane, wherein the porous membrane is coated on an outer surface of the fluid guide plate.

[0010] In some embodiments, the fluid deflector is made of metal foam or ceramic foam.

[0011] In some embodiments, the pore size of the fluid deflector is larger than the pore size of the porous membrane. In some embodiments, the pore size of the fluid deflector is 10-2000 μm, preferably, the pore size of the fluid deflector is 50-200 μm. In some embodiments, the pore size of the porous membrane is no greater than 100 μm, preferably, the pore size of the porous membrane is 1-20 μm.

[0012] In some embodiments, the system for performing an electrochemical reaction further includes a flow diversion unit configured to be connected to the first end of the microchannel unit so that the electrolyte is evenly diverted to the microchannel unit via the flow diversion unit.

[0013] In some embodiments, the flow diversion unit includes: a flow diversion chamber and a dispersion array. In these embodiments, the flow diversion array is located between the flow diversion chamber and the microfluidic channel unit.

[0014] In some embodiments, the flow diverter array includes a plurality of openings spaced apart from one another.

[0015] In some embodiments, the first electrode and the second electrode are both gas diffusion electrodes. In some embodiments, the distance between the first electrode and the second electrode does not exceed 2 mm, preferably, the distance between the first electrode and the second electrode does not exceed 1 mm.

[0016] In some embodiments, the system provided according to the first aspect of the present invention is an electrolysis cell.

[0017] In some embodiments, the system provided according to the first aspect of the present invention is a fuel cell.

[0018] According to a second aspect of the present invention, there is provided a method for performing an electrochemical reaction using a system according to the first aspect of the present invention, the method comprising: providing an electrolyte so that the electrolyte flows evenly into a microfluidic unit; and allowing the electrolyte to seep out from the microporous structure of the side wall of the microfluidic unit to contact the first electrode and the second electrode.

[0019] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other features, advantages and aspects of the embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements.

[0021] FIG1A shows a schematic diagram of a system for performing an electrochemical reaction.

[0022] FIG. 1B shows a schematic diagram of another system for performing an electrochemical reaction.

[0023] FIG2 shows a schematic diagram of a system for performing an electrochemical reaction according to an embodiment of the present invention.

[0024] FIG. 3A is a schematic diagram showing an exemplary structure of multiple flow channels within a micro-flow channel unit according to an embodiment of the present invention.

[0025] FIG. 3B is a schematic diagram showing another exemplary structure of multiple flow channels within a micro-flow channel unit according to an embodiment of the present invention.

[0026] FIG4 shows a schematic diagram of a microfluidic channel unit according to an embodiment of the present invention.

[0027] FIG5 shows a schematic diagram of a diversion unit according to an embodiment of the present invention.

[0028] FIG6 shows a schematic diagram of a system for performing an electrochemical reaction according to yet another embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following description of exemplary embodiments of the present invention is provided in conjunction with the accompanying drawings, in which various details of the embodiments of the present invention are included to facilitate understanding. These details should be considered as merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0030] As used herein, the term "including" and its variations represent open inclusion, i.e., "including but not limited to." Unless otherwise stated, the term "or" means "and / or." The term "based on" means "based at least in part on." The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0031] Hydrogen production from water electrolysis is an important method for producing hydrogen through electrochemical reactions. Alkaline water electrolysis is widely used in industry due to its low cost and high technological maturity. Conventional alkaline water electrolysis typically employs an electrochemical reaction system (also known as an alkaline electrolyzer) 100A, as shown in FIG1A .

[0032] FIG1A shows a schematic diagram of a system 100A for performing an electrochemical reaction. As shown in FIG1A , the system 100A includes: a first electrode 110A, a second electrode 120A and a diaphragm 130A, wherein the diaphragm 130A divides the system 100A into a first chamber 102A and a second chamber 104A. In the process of using the system 100A for water electrolysis, an electrolyte (such as potassium hydroxide, sodium hydroxide, etc.) is passed into the first chamber 102A and the second chamber 104A, and the first electrode 110A and the second electrode 120A are completely immersed in the electrolyte so that oxygen and hydrogen can be formed on the surfaces of the first electrode 110A and the second electrode 120A, respectively. Taking the first electrode 110A as the anode and the second electrode 120A as the cathode as an example, in the process of performing the electrochemical reaction of water electrolysis, an oxygen evolution reaction shown in the following formula (1) occurs at the first electrode 110A. 4OH - →2H2O+O2+4e - (1)

[0033] The hydrogen evolution reaction occurs at the second electrode 120A as shown in the following formula (2): 2H2O+4e - →H2+2OH - (2)

[0034] However, as shown in FIG1A , hydrogen and oxygen form bubbles on the surfaces of the corresponding electrodes, which easily causes gas blockage, thereby hindering the occurrence of the electrochemical reaction and reducing hydrogen production efficiency. Secondly, although a diaphragm 130A (such as an asbestos diaphragm, a polyphenylene sulfide (PPS) diaphragm, a composite diaphragm, or other diaphragms) is provided in the system 100A to prevent the mixing of hydrogen and oxygen, given that the production ratio of hydrogen and oxygen is 2:1, it is necessary to maintain the pressure balance between the first chamber 102A and the second chamber 104A on both sides of the diaphragm 130A at all times. Otherwise, if the pressure of the two chambers is unbalanced, the excess hydrogen will pass through the diaphragm 130A and mix with the oxygen, thereby causing an explosion risk.

[0035] Alternatively, in the prior art, porous capillaries can be used to bring the electrolyte into contact with the electrodes based on the capillary effect. Figure 1B shows a schematic diagram of another system 100B for performing an electrochemical reaction.

[0036] As shown in FIG1B , system 100B includes a first electrode 110B, a second electrode 120B, a porous capillary 130B, and an electrolyte container 140B. Porous capillary 130B is located between first electrode 110B and second electrode 120B, with the bottom end of porous capillary 130B extending into electrolyte container 140B. During water electrolysis using system 100B, the electrolyte in electrolyte container 140B spontaneously flows into porous capillary 130B due to the capillary effect and rises along porous capillary 130B to a certain height, where it contacts first electrode 110B and second electrode 120B, thereby generating oxygen and hydrogen.

[0037] However, the electrolyte's ability to rise high within the porous capillary 130B due to the capillary effect is limited, thus limiting the size of the system 100B. Furthermore, as shown in FIG1B , since the porous capillary 130B is disposed between the first electrode 110B and the second electrode 120B, if the spacing between the first electrode 110B and the second electrode 120B is small or the electrodes are relatively tightly positioned on either side of the porous capillary 130B, the electrodes are unlikely to have completely flat surfaces, which could easily lead to the pores of the porous capillary 130B being crushed, deformed, or even completely closed, thereby affecting the capillary effect. Furthermore, since the generated oxygen and hydrogen are actually isolated by the electrolyte in the porous capillary 130B, if the electrolyte in the porous capillary 130B rises discontinuously, for example, the electrolyte fails to rise to a certain height along the porous capillary 130B or gaps appear in the middle of the electrolyte in the porous capillary 130B, there will be a risk of hydrogen and oxygen mixing.

[0038] In summary, the disadvantages of the above-mentioned existing systems for performing electrochemical reactions are: large electrode spacing, easy occurrence of gas blockage at the electrodes, low hydrogen production efficiency, and the risk of hydrogen and oxygen mixing.

[0039] In order to at least partially solve one or more of the above-mentioned problems and other potential problems, an exemplary embodiment of the present invention proposes a system for performing an electrochemical reaction. In at least one electrochemical reaction subsystem included in the system, a microfluidic unit having a rigidity that meets predetermined conditions and is used to circulate an electrolyte is provided between a first electrode and a second electrode to avoid deformation of the microfluidic unit during the electrochemical reaction, so that the first electrode and the second electrode can be tightly arranged on opposite sides of the microfluidic unit, thereby reducing the electrode spacing. At the same time, by allowing the electrolyte to fully fill the microfluidic unit to form a liquid partition, the occurrence of hydrogen and oxygen mixing is avoided. In addition, by allowing the electrolyte to seep out from the microporous structure on the side wall of the microfluidic unit and contact the electrode, the occurrence of gas blockage at the electrode can be greatly reduced, thereby improving the efficiency of hydrogen production.

[0040] A scheme for performing an electrochemical reaction according to an embodiment of the present invention will be described in detail below with reference to FIG. 2 to FIG. 6 .

[0041] FIG2 shows a schematic diagram of a system 200 for performing an electrochemical reaction according to an embodiment of the present invention.

[0042] As shown in FIG. 2 , the system 200 includes an electrochemical reaction subsystem 210 , wherein the electrochemical reaction subsystem 210 may include: a first electrode 214 , a second electrode 216 and a microfluidic channel unit 212 .

[0043] The first electrode 214 and the second electrode 216 may be configured to contact an electrolyte to generate corresponding gases. According to an embodiment of the present invention, the electrolyte may be, for example, a sodium hydroxide solution. If the first electrode 214 is an anode and the second electrode 216 is a cathode, then, as described above, oxygen gas is generated at the first electrode 214 and hydrogen gas is generated at the second electrode 216.

[0044] In order to better diffuse and guide the gas generated at the electrode to avoid gas resistance, according to an embodiment of the present invention, a gas diffusion layer can be provided on the side of the electrode away from the microchannel unit 212. As shown in FIG2 , a first gas diffusion layer 224 is provided on the side of the first electrode 214 away from the microchannel unit 212, and a second gas diffusion layer 226 is provided on the side of the second electrode 216 away from the microchannel unit 212. In this embodiment, the gas (such as oxygen) generated at the first electrode 214 can diffuse through the first gas diffusion layer 224 and be guided out of the electrochemical reaction subsystem 210, for example, into an external pipeline (not shown) for transporting oxygen; similarly, the gas (such as hydrogen) generated at the second electrode 216 can diffuse through the second gas diffusion layer 226 and be guided out of the electrochemical reaction subsystem 210, for example, into an external pipeline (not shown) for transporting hydrogen.

[0045] According to some other embodiments of the present invention, the electrodes may also be gas diffusion electrodes. For example, the first electrode 214 and the second electrode 216 shown in FIG2 are both gas diffusion electrodes, so that the gas formed at the electrodes can be fully diffused through the gas diffusion electrodes.

[0046] Regarding the gas diffusion electrode, it is preferred to use a gas diffusion electrode with a larger number of through holes and a larger porosity to achieve a better diffusion effect of the gas in the electrode, thereby enabling the gas to be more fully discharged from the electrochemical reaction subsystem 210 to the outside.

[0047] In some other embodiments, when the electrode is a gas diffusion electrode and the thickness of the electrode is large enough, the electrode itself will have the function of a gas diffusion layer. In other words, the electrode can be used to replace the above-mentioned combined structure of the electrode and the gas diffusion layer, so that the gas diffusion layer may not be included in the structure of these embodiments.

[0048] 2 , the microchannel unit 212 is located between the first electrode 214 and the second electrode 216 for circulating the electrolyte. According to some embodiments of the present invention, the electrolyte can flow into the microchannel unit 212 from above and out from below.

[0049] According to an embodiment of the present invention, the sidewalls of the microfluidic unit 212 facing the first electrode 214 and the second electrode 216 have a microporous structure to facilitate the electrolyte flowing into the microfluidic unit 212 to seep out through the microporous structure and contact the electrodes. In some embodiments, the pore size of the micropores on the sidewalls of the microfluidic unit 212 can be 1-100 μm.

[0050] According to the inventive concept of the present invention, the micro-channel unit 212 is further configured to have a rigidity that meets a predetermined condition, so as to prevent the micro-channel unit 212 from being deformed during an electrochemical reaction.

[0051] Regarding the rigidity that meets the predetermined conditions, it means that the shape of the microfluidic unit 212 remains unchanged during the process in which the electrolyte therein seeps out and undergoes an electrolytic reaction with the electrodes (i.e., the first electrode 214 and the second electrode 216), thereby avoiding excessive deformation of the microfluidic unit 212 due to the pressure of the first electrode 214 and the second electrode 216, that is, avoiding excessive local deformation of the microfluidic unit 212, so that the electrolyte cannot enrich the microfluidic unit 212, thereby causing the microfluidic unit 212 to include a local blank area without electrolyte, so that there is a risk of hydrogen and oxygen mixing through the local blank area.

[0052] According to some embodiments of the present invention, microfluidic channels can be provided in the microfluidic unit 212 to support the shape of the microfluidic unit 212, thereby ensuring that the microfluidic unit 212 has a rigidity that meets predetermined conditions and prevents deformation. For example, in some embodiments, the microfluidic unit 212 can have multiple channels, so that the electrolyte flowing into the first end of the microfluidic unit 212 can flow out of the second end of the microfluidic unit 212 through the multiple channels. In other embodiments, the electrolyte can also flow into the microfluidic unit 212 from both the first and second ends of the microfluidic unit 212 at the same time.

[0053] Furthermore, in some embodiments, the electrolyte can be passed through the microfluidic unit using external forces such as liquid gravity and / or hydraulic pressure from a pump valve, so that the electrolyte fills the entire microfluidic unit, thereby preventing the formation of gaps in the electrolyte in the microfluidic unit. In this case, the first end of the microfluidic unit can be located above the second end of the microfluidic unit, so that the electrolyte can flow into the microfluidic unit from the upper port and flow out of the lower port of the microfluidic unit through the multiple flow channels.

[0054] Regarding the flow channel, it may refer to a fluid channel with a smaller thickness. According to an embodiment of the present invention, the thickness of the flow channel may be no more than 1 mm, preferably, the thickness of the flow channel may be no more than 0.5 mm, such as 0.2 mm or 0.02 mm. By passing the electrolyte through the flow channel with a smaller thickness in the microfluidic unit 212, the circulation of the electrolyte can be made more controllable, thereby better controlling the electrolyte to seep out of the microfluidic unit to react with the electrode, in other words, helping to improve the controllability of the electrochemical reaction. Moreover, since the thickness of the flow channel is small, the thickness of the microfluidic unit 212 is also small accordingly, which can make the system 200 have a smaller electrode spacing. In some embodiments, the flow channel may be a microfluidic channel so that the electrolyte flowing through the microfluidic unit 212 exhibits the properties of a microfluidic.

[0055] According to some embodiments of the present invention, the structure of the multiple flow channels within the microfluidic unit 212 may be irregular, for example, the multiple flow channels may be in a three-dimensional grid shape or a sponge shape. According to some other embodiments of the present invention, the structure of the multiple flow channels within the microfluidic unit 212 may be regular, for example, the multiple flow channels are arranged in parallel. Figures 3A and 3B exemplarily illustrate the structure of the multiple flow channels within the microfluidic unit 212. Specifically, the multiple flow channels within the microfluidic unit shown in Figure 3A have an irregular sponge-like structure; the multiple flow channels within the microfluidic unit shown in Figure 3B have a regular structure arranged in parallel.

[0056] According to an embodiment of the present invention, the flow channel can be made of materials such as metal, ceramic, hard plastic, or alkali-resistant hard materials suitable for making flow channels, so as to support the shape of the microfluidic unit 212 and prevent the microfluidic unit 212 from deforming.

[0057] According to other embodiments of the present invention, the micro-channel unit 212 may also have a "sandwich" structure as shown in Figure 4. This will be described in detail below in conjunction with Figure 4 and will not be repeated here.

[0058] As can be seen from the above, in the system 200 for performing an electrochemical reaction according to an embodiment of the present invention, since the microfluidic unit 212 in the electrochemical reaction subsystem 210 has a rigidity that meets predetermined conditions, the first electrode 214 and the second electrode 216 can be tightly arranged on both sides of the microfluidic unit 212, and at the same time, the microfluidic unit 212 will not be excessively deformed due to being squeezed by the first electrode 214 and the second electrode 216, thereby achieving a smaller electrode spacing.

[0059] According to an embodiment of the present invention, the distance between the first electrode 214 and the second electrode 216 may be, for example, no greater than 2 mm. In some other embodiments, the distance between the first electrode 214 and the second electrode 216 may be no greater than 1 mm, such as 0.8 mm.

[0060] As shown in FIG2 , the electrochemical reaction subsystem 210 may further include: a first bipolar plate 234 and a second bipolar plate 236, wherein the first bipolar plate 234 is disposed on the outside of the first gas diffusion layer 224, i.e., on the side of the first gas diffusion layer 224 away from the first electrode 214; and the second bipolar plate 236 is disposed on the outside of the second gas diffusion layer 226, i.e., on the side of the second gas diffusion layer 226 away from the second electrode 216. By using bipolar plates, multiple electrochemical reaction subsystems can be stacked to form a system for performing an electrochemical reaction including multiple electrochemical reaction subsystems, which will be described below in conjunction with FIG6 and will not be repeated here.

[0061] According to an embodiment of the present invention, metal bipolar plates may be used. For example, the first bipolar plate 234 and the second bipolar plate 236 may both be metal bipolar plates.

[0062] In the system 200 for performing an electrochemical reaction according to the embodiment of the present invention described above, when water electrolysis is performed using the system 200, the electrolyte flowing into the microchannel unit 212 can slowly seep out from the microporous structure on both sides of the microchannel unit 212 and contact the first electrode 214 and the second electrode 216 on both sides of the microchannel unit 212 to generate hydrogen and oxygen respectively. Since the microchannel unit 212 allows the slowly seeping electrolyte to contact the electrodes, the gas generated at the electrodes can effectively contact the gas cavity in the cavity where the electrodes are located through the electrodes, thereby reducing the possibility of gas resistance at the electrodes. In addition, since the microchannel unit 212 has a rigidity that meets predetermined conditions, when the electrode spacing is small, the microchannel unit 212 can still keep the flow channel therein unobstructed, so that the electrolyte can fully circulate in the flow channel.

[0063] Figure 4 shows a schematic diagram of a microfluidic unit 400 having a "sandwich" structure according to an embodiment of the present invention. As shown in Figure 4 , the microfluidic unit 400 may include a fluid guide plate 410 and a porous membrane 420 , wherein the porous membrane 420 is coated on the outer surface of the fluid guide plate 410 .

[0064] Regarding the fluid guide plate 410, it can be a fluid guide plate having a rigidity that meets predetermined conditions so that the fluid guide plate 410 does not deform due to the pressure applied by the electrodes on both sides. According to embodiments of the present invention, the fluid guide plate 410 can be made of a material that does not react with the electrolyte and is stable over the long term. For example, the fluid guide plate 410 can be made of metal foam (such as nickel foam) or ceramic foam. According to some embodiments of the present invention, the fluid guide plate 410 can also be a microfluidic guide plate.

[0065] The porous membrane 420 can be a thin film having numerous small pores and stable chemical properties. For example, it can be a polymer membrane having a certain number of uniform small pores. According to an embodiment of the present invention, the porous membrane 420 can be a porous membrane having strong alkali resistance. In some embodiments, the porous membrane 420 can be, for example, a polyethersulfone (PES) porous membrane, a melamine porous membrane, or other suitable porous membrane.

[0066] The outer surface of the fluid guide plate 410 refers to the outer surface of the side of the fluid guide plate 410. According to an embodiment of the present invention, the porous membrane 420 is coated on the outer surface of the fluid guide plate 410 facing the electrode.

[0067] According to the inventive concept of the present invention, in some embodiments, the pore size of the fluid guide plate 410 can be different from the pore size of the porous membrane 420. For example, the pore size of the fluid guide plate 410 can be larger than the pore size of the porous membrane 420, so that the electrolyte can fully circulate in the fluid guide plate 410, while ensuring that the electrolyte in the fluid guide plate 410 slowly seeps out from the porous membrane 420 to contact the electrode. For example, the pore size of the fluid guide plate 410 can be 10-2000 μm, preferably, the pore size of the fluid guide plate 410 can be 50-200 μm, such as 100 μm. For example, the pore size of the porous membrane 420 can be no greater than 100 μm, preferably, the pore size of the porous membrane 420 can be 1-20 μm, such as 5 μm.

[0068] According to the inventive concept of the present invention, the micro-channel unit 400 can be formed in an integral manner or in separate parts, which is not limited here.

[0069] According to an embodiment of the present invention, the cross section of the micro-fluidic channel unit 400 may be rectangular.

[0070] Furthermore, in order to allow the electrolyte to fully fill the microchannel unit to form a liquid partition, the system for performing an electrochemical reaction according to an embodiment of the present invention may further include a shunt unit, so that the electrolyte can first flow into the shunt unit and further shunt to the microchannel unit via the shunt unit. Specifically, in some embodiments, the shunt unit can be configured to be connected to one end of the microchannel unit (e.g., the microchannel unit 212 of FIG. 2 or the microchannel unit 400 of FIG. 4 ) so that the electrolyte is evenly shunt to the microchannel unit via the shunt unit.

[0071] FIG5 shows a schematic diagram of a flow diversion unit 500 according to an embodiment of the present invention. The flow diversion unit 500 can be connected to one end of the microchannel unit 212 shown in FIG2 .

[0072] As shown in FIG. 5 , the flow diversion unit 500 may include a flow diversion chamber 510 and a dispersion array 520 , wherein the dispersion array 520 may be located between the flow diversion chamber 510 and the micro-channel unit 212 .

[0073] Regarding the diversion chamber 510, one end thereof may be connected to a pipeline for conveying electrolyte. When the electrolyte in the pipeline flows into the diversion chamber 510, the flow cross-section of the electrolyte may be expanded by the diversion chamber 510. According to an embodiment of the present invention, the cross-sectional area of ​​the bottom end of the diversion chamber 510 may be the same as the cross-sectional area of ​​the microfluidic unit 212. In this case, the flow cross-sectional area of ​​the electrolyte flowing into the diversion chamber 510 may be expanded to the same cross-sectional area as the microfluidic unit 212.

[0074] Regarding the dispersion array 520, it can be used to balance the pressure of the electrolyte after the cross-section of the liquid flow is expanded, and to disperse the electrolyte into the microfluidic unit 212, thereby achieving the purpose of filling the entire microfluidic unit 212 with electrolyte. Specifically, by using the dispersion array 520, a more uniform flow field of the electrolyte can be formed, so that the electrolyte flowing into the microfluidic unit 212 flows evenly through the multiple flow channels in the microfluidic unit 212, avoiding uneven internal resistance caused by uneven electrolyte concentration in different parts during the electrochemical reaction. According to some embodiments of the present invention, the dispersion array 520 may include multiple openings spaced apart from each other.

[0075] It should be understood that FIG5 merely illustrates the structure of the diverter unit 500. In some embodiments, the diverter chamber 510 and the dispersion array 520 in the diverter unit 500 may be arranged perpendicular to the cross-section of one end of the microfluidic unit 212; in other embodiments, the diverter chamber 510 and the dispersion array 520 in the diverter unit 500 may be arranged horizontally to the cross-section of one end of the microfluidic unit 212; in still other embodiments, either the diverter chamber 510 or the dispersion array 520 in the diverter unit 500 may be arranged horizontally to the cross-section of one end of the microfluidic unit 212, while the other may be arranged perpendicular to the cross-section. The present invention is not limited thereto.

[0076] In summary, through the diversion unit as described above, the electrolyte can quickly fill the flow channel in the microchannel unit completely and evenly, that is, the electrolyte can fully fill the microchannel unit to form a liquid partition, thereby achieving liquid phase isolation of hydrogen and oxygen and avoiding the occurrence of hydrogen and oxygen mixing.

[0077] FIG6 shows a schematic diagram of a system 600 for performing an electrochemical reaction according to yet another embodiment of the present invention.

[0078] As shown in Figure 6, system 600 includes three electrochemical reaction subsystems, namely a first electrochemical reaction subsystem 610, a second electrochemical reaction subsystem 620 and a third electrochemical reaction subsystem 630, wherein the first electrochemical reaction subsystem 610 and the second electrochemical reaction subsystem 620 share a third bipolar plate 602, and the second electrochemical reaction subsystem 620 and the third electrochemical reaction subsystem 630 share a fourth bipolar plate 604.

[0079] Thus, the electrochemical reaction subsystems can be stacked by bipolar plates, thereby realizing the industrial production of the system for performing electrochemical reaction according to the embodiment of the present invention.

[0080] In summary, the system for performing electrochemical reactions according to an embodiment of the present invention can safely and efficiently realize hydrogen production by electrolysis of water when the electrode spacing is small, and because the rigid microfluidic unit that meets the predetermined conditions can completely isolate the oxygen and hydrogen produced by electrolysis of water without the risk of mutual mixing, the system provided by the present invention can be operated at normal pressure, thereby reducing energy consumption.

[0081] According to another aspect of the present invention, the system for performing an electrochemical reaction can also be used as a fuel cell. According to some embodiments of the present invention, the first electrode 214 and the second electrode 216 in the system 200 shown in FIG2 can be catalytically active electrodes, such as platinum carbon (Pt / C) catalytic electrodes, iridium oxide (IrO2) catalytic electrodes, or any other electrodes suitable for fuel cells. By introducing hydrogen and oxygen into the first electrode 214 and the second electrode 216, respectively, corresponding electrochemical reactions occur at the first electrode 214 and the second electrode 216, and a current is generated.

[0082] Taking the first electrode 214 as the positive electrode and the second electrode 216 as the negative electrode as an example, when the system 200 is used as a fuel cell, oxygen is introduced into the first electrode 214 to perform an oxygen reduction reaction (ORR) at the first electrode 214, and hydrogen is introduced into the second electrode 216 to perform a hydrogen oxidation reaction (HOR) at the second electrode 216. The hydroxide ions generated at the first electrode 214 then move to the second electrode 214 via the electrolyte in the microchannel unit 212 to react with the hydrogen ions at the second electrode 214 to generate water. Accordingly, electrons flow out of the second electrode 216 and flow into the first electrode 214 via, for example, a conductive device (such as the first gas diffusion layer 224, the first bipolar plate 234, the second gas diffusion layer 226, the second bipolar plate 236 shown in FIG. 2, etc., which are included in the system 200 and / or any conductive device applicable to the present invention and disposed outside the system) to form an electric current.

[0083] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0084] The above are merely optional embodiments of the present disclosure and are not intended to limit the present disclosure. Those skilled in the art will readily appreciate that the present disclosure may be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A system for performing an electrochemical reaction, characterized in that, comprising at least one electrochemical reaction subsystem, wherein the electrochemical reaction subsystem comprises: a first electrode; a second electrode; and a microchannel unit located between the first electrode and the second electrode for allowing an electrolyte to flow therethrough, wherein side walls of the microchannel unit facing the first electrode and the second electrode have a microporous structure, and the microchannel unit is configured to have a rigidity satisfying a predetermined condition to avoid deformation of the microchannel unit during an electrochemical reaction.

2. The system according to claim 1, wherein The microchannel unit has a plurality of channels such that the electrolyte flowing into the microchannel unit from a first end thereof flows out of the microchannel unit from a second end thereof via the plurality of channels.

3. The system according to claim 2, wherein The first end of the microchannel unit is located above the second end of the microchannel unit; and the channels are made of at least one of the following materials: metal, ceramic, and hard plastic.

4. The system according to claim 1, wherein The microchannel unit comprises: a fluid flow guiding plate; and a porous membrane covering an outer surface of the fluid flow guiding plate.

5. The system according to claim 4, wherein The fluid flow guiding plate is made of metal foam or ceramic foam.

6. The system according to claim 4, wherein The pore size of the fluid flow guiding plate is larger than the pore size of the porous membrane, wherein the pore size of the fluid flow guiding plate is 10 - 2000 μm, preferably, the pore size of the fluid flow guiding plate is 50 - 200 μm, wherein the pore size of the porous membrane is not more than 100 μm, preferably, the pore size of the porous membrane is 1 - 20 μm.

7. The system according to claim 1, wherein Further comprising: a flow splitting unit configured to be connected to the first end of the microchannel unit to uniformly split the electrolyte into the microchannel unit.

8. The system according to claim 7, characterized in that, The flow splitting unit comprises: a flow splitting chamber and a dispersion array, wherein the dispersion array is located between the flow splitting chamber and the microchannel unit, and the dispersion array comprises a plurality of openings spaced from each other.

9. The system according to claim 1, characterized in that, Both the first electrode and the second electrode are gas diffusion electrodes, wherein the distance between the first electrode and the second electrode does not exceed 2 mm, preferably, the distance between the first electrode and the second electrode does not exceed 1 mm.

10. The system according to claim 1, wherein, The system is an electrolytic cell.

11. The system according to claim 1, wherein The system is a fuel cell.

12. A method for performing an electrochemical reaction using the system according to any one of claims 1 to 11, the method comprising: providing an electrolyte such that the electrolyte uniformly enters the microchannel unit; and causing the electrolyte to seep out from the microporous structure of the side wall of the microchannel unit to contact the first electrode and the second electrode.

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