CN216891249U - Proton exchange membrane water electrolyzer and system - Google Patents

Abstract

The utility model provides a water electrolyzer with proton exchange membrane and a system. The electrolytic bath comprises a membrane electrode, end plates, an anode flow field assembly and a cathode flow field assembly, wherein at least one end plate is provided with an opening for discharging gas and water, the flow field assembly is provided with flow guide holes communicated with the opening, the flow field assembly is provided with a diffusion structure layer, a bipolar plate, a flow passage sealing gasket and a flow passage plate along the direction far away from the membrane electrode, the bipolar plate is provided with a through groove, the flow passage plate is provided with a through groove, a shallow groove and a communicating narrow groove, a gap is arranged between the bipolar plate and the flow passage plate, and the through groove of the bipolar plate, the through groove of the flow passage plate, the shallow groove, the communicating narrow groove, the flow passage plate and the gap between the bipolar plate are communicated with each other to form a water storage and exhaust cavity. The utility model can greatly reduce the processing difficulty of the flow field structure of the water electrolysis bath, reduce the processing cost, contribute to prolonging the service life of the electrolysis bath and realize the pumpless operation of the water electrolysis bath.

Description

Proton exchange membrane water electrolyzer and system

Technical Field

The utility model relates to the technical field of electrolyzed water, in particular to a water electrolyzer with an proton exchange membrane and a system.

Background

The bottleneck of the water electrolysis hydrogen production of PEM (polymer electrolyte membrane, also called proton exchange membrane) at present lies in the service life and cost of the electrolytic cell. The life of the membrane electrode is a major factor in determining the life of the cell. The lifetime of existing membrane electrodes is actually limited in two ways, one being the lifetime of the catalyst, but the lifetime of the catalyst has been greatly advanced in recent years. Another problem affecting the life of the membrane electrode is the geometric structure of the electrolyzer, especially the flow field structure, and poor flow field design can cause fatal defects such as water shortage and overheating of the membrane electrode, so that the membrane electrode fails prematurely.

The traditional PEM electrolyzer is formed by stacking and connecting a titanium bipolar plate, a titanium felt collector, a proton membrane electrode coated with a catalyst and other components in a multi-layer manner through bolts by two end plates and then tightly pressing the components together. Usually, a water outlet is arranged at the upper part of the electrolytic bath, a water inlet is arranged at the lower part of the electrolytic bath, and the continuous supply of water is completed by a water pump. Complicated and narrow flow channels (usually about 1mm in width and over 0.3mm in depth) need to be engraved on two sides or one side of the bipolar plate. The method for making the flow channel includes several methods, one is etching by electric spark machining, the other is engraving and milling by an engraving and milling machine, and the other is also forming the flow channel by punching titanium foil with the thickness of about 0.05-0.8mm, and then welding or gluing frames on two sides so as to seal and separate gas on two sides. However, the former two methods usually process a bipolar plate with a flow field area of 100 square centimeters, which requires ten hours and more hours on a high-speed CNC machine tool or an electric spark machine, and it is difficult to ensure the consistency of the processing quality over the whole area, not to mention the thousands of square centimeters of bipolar plates used on a large-scale electrolytic cell, and the processing is time-consuming, the yield is difficult to ensure, and the processing cost is extremely high. In the latter stamping method, due to the characteristics of titanium, when the thickness of the titanium foil is too thin, the stamped runner cannot provide enough supporting force, the runner collapses in use, and when the thickness of the titanium foil is too thick, a flat deep runner with a small distance (less than 1mm) cannot be stamped, so that the realizability and the electrical performance of the bipolar plate are not satisfactory.

The more fatal problem is that when the electrode area is large, the flow channel depth is not enough (the narrow and deep flow channel is very difficult to process), and the generated air flow can occupy the flow channel when the electrolytic cell is operated at a high current density (>1A cm < -2 >), so that the water shortage at the upper part of the electrolytic cell is caused locally, thereby causing overheating, and the service life of the electrolytic cell is seriously influenced.

Patent CN 211556044U discloses an electrolytic cell and anode electrode plate (i.e. bipolar plate) structure, wherein 2 to 100 strip-shaped grooves are left on the anode electrode plate, and a water guide plate is arranged on the anode side, so that the vertical use mode may still cause gas accumulation on the upper part of the electrolytic cell to cause local water shortage. The large electrolytic cell is usually formed by connecting multiple units in series, the electrode plate simultaneously plays a role in providing a flow field and isolating gas on two sides, and the multiple units are connected in series into a whole with severe sealing requirements. And the water-way and gas-way management of the cathode hydrogen outlet side in a large-scale electrolytic cell is also extremely important, and obviously, the patent does not improve the cathode side.

It is therefore critical to develop an electrolytic cell structure that can be used in a multi-stage series configuration while providing a smooth flow path. Meanwhile, the bipolar plate accounts for about 48% of the cost of the electrolytic cell, so that it is very important to find a new flow field structure and improve the processing manner of the bipolar plate so as to reduce the cost and improve the processability.

SUMMERY OF THE UTILITY MODEL

In view of the above disadvantages of the prior art, the present invention aims to provide a water electrolyzer with proton exchange membrane and a system thereof, which are used for solving the problems of the PEM water electrolyzer in the prior art, such as high processing difficulty and high processing cost, poor flow field problems of unsmooth water path and gas path, water shortage, etc., existing in the water electrolyzer, and short service life of the water electrolyzer due to easy local water shortage and overheating.

In order to achieve the above and other related objects, the present invention provides an pem water electrolyzer comprising a membrane electrode, end plates, an anode flowfield assembly and a cathode flowfield assembly, wherein the anode flowfield assembly and the cathode flowfield assembly are located on opposite sides of the membrane electrode, the end plates are respectively located at one ends of the anode flowfield assembly and the cathode flowfield assembly, which are far away from the membrane electrode, at least one end plate is provided with openings for discharging gas and water, the anode flowfield assembly and the cathode flowfield assembly are respectively provided with flow guide holes communicated with the openings, and the anode flowfield assembly and the cathode flowfield assembly are provided with a diffusion structure layer, a bipolar plate, a flow channel sealing gasket and a flow channel plate along a direction far away from the membrane electrode, wherein the bipolar plate is provided with through grooves, the flow channel plate is provided with through grooves, non-through shallow grooves, and non-through shallow grooves, And the communicating narrow groove is used for communicating the through groove and the shallow groove of the flow passage plate with the flow guide hole, a gap is arranged between the bipolar plate and the flow passage plate, and the through groove of the bipolar plate, the through groove and the shallow groove of the flow passage plate, the communicating narrow groove, the flow passage plate and the gap between the bipolar plate are communicated with each other to form a water storage and exhaust cavity.

Optionally, the through grooves and the shallow grooves of the flow passage plate are arranged in a crossing manner and communicated with each other.

Alternatively, the through grooves of the bipolar plate form a comb structure, and the through grooves on the same comb structure are communicated with each other.

Optionally, the tooth width of the through groove on the same comb tooth structure is 0.1-3mm, and the groove width of the through groove is 0.5-5 mm.

Optionally, the plurality of through grooves of the bipolar plate are interconnected and distributed in a serpentine shape.

Optionally, the diffusion structure layer comprises a current collector and a current collector gasket.

Optionally, a membrane electrode compensation pad is further disposed between the membrane electrode and the negative electrode flow field assembly.

Optionally, the flow channel gasket and the flow channel plate are non-titanium material plates, and the flow channel plate is a rigid material plate.

Optionally, the proton exchange membrane water electrolyzer further comprises a blind plate for preventing the end plate from polluting water quality, and the blind plate is positioned between the negative electrode flow field assembly and the end plate.

Optionally, the proton exchange membrane water electrolyzer comprises a plurality of anode flow field assemblies, a plurality of cathode flow field assemblies and a plurality of unit partition plates, wherein the anode flow field assemblies and the cathode flow field assemblies are alternately arranged to form a plurality of electrolytic water units which are connected in series, the unit partition plates are provided with flow guide holes, the unit partition plates do not participate in electric conduction, and adjacent electrolytic water units are separated by gas through the unit partition plates.

Optionally, the proton exchange membrane water electrolyzer further comprises a conductive sheet, and the bipolar plate of each water electrolysis unit extends outwards to be electrically connected with the conductive sheet.

The utility model also provides a proton exchange membrane water electrolysis system, which comprises a water tank and the proton exchange membrane water electrolysis cell in any scheme, wherein the proton exchange membrane water electrolysis cell is horizontally placed below the water tank in a mode that the anode oxygen evolution surface faces upwards and is communicated with the water tank.

As described above, the proton exchange membrane water electrolyzer and the system of the present invention have the following beneficial effects: through the improved structural design, the processing difficulty of the flow field structure of the water electrolyzer can be greatly reduced, the processing cost is reduced, the smoothness of water flow in the water electrolyzer can be obviously improved, the phenomenon of water shortage and overheating of a membrane electrode is avoided, the service life of the water electrolyzer is prolonged, the complexity of a system is reduced, and the pumpless operation of the large proton exchange membrane water electrolyzer is realized.

Drawings

Fig. 1 is a schematic view showing an exemplary assembly structure of a proton exchange membrane water electrolyzer provided in the utility model.

Fig. 2 shows an exemplary exploded view of the pem water electrolyzer provided in the present invention.

FIG. 3 is a schematic view showing the use state of the proton exchange membrane water electrolyzer provided by the utility model.

Fig. 4 shows a schematic view of a flow field in the process of electrolyzing water in the proton exchange membrane water electrolyzer provided by the utility model.

Fig. 5 is a schematic structural diagram of a bipolar plate of a pem water electrolyzer according to the present invention in an example.

Fig. 6 is a schematic structural diagram of a bipolar plate of a pem water electrolyzer according to another embodiment of the present invention.

Fig. 7 and 8 are schematic views showing exemplary structures of the flow field plates of the pem water electrolyzer provided in the present invention on two opposite sides.

FIG. 9 is an exploded view of another example of a PEM water electrolyzer according to the present invention.

FIG. 10 is a schematic flow diagram illustrating the flow of water and air to a PEM water electrolyzer according to an embodiment of the present invention.

Fig. 11 is a schematic view of the flow field of fig. 10.

Description of the element reference

100 proton exchange membrane water electrolyzer

1 film electrode

2 end plate

3 unit partition board

41 Current collector

42 current collector gasket

43 Bipolar plate

431 diversion hole

432 through groove

44 flow passage plate

441 through groove

442 shallow groove

443 communicating narrow groove

444 diversion hole

45 flow passage sealing gasket

51 Current collector

52 current collector gasket

53 bipolar plate

54 flow passage plate

55 flow passage sealing gasket

6 membrane electrode compensation pad

7 conducting strip

8 water tank

81 hydrogen tank

82 oxygen tank

83 communication hole

Detailed Description

The following embodiments of the present invention are provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The utility model is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated. In order to keep the drawings as concise as possible, not all features of a single figure may be labeled in their entirety.

The traditional multistage PEM electrolyzer is formed by tightly pressing a titanium electrode plate, a titanium felt current collector, a proton membrane electrode coated with a catalyst and the like together after the components are stacked in multiple stages by two end plates through bolts. Usually, a water outlet is arranged at the upper part of the electrolytic cell, a water inlet is arranged at the lower part of the electrolytic cell, and the continuous supply of water in the reaction is completed through a water pump. The electrode plates are generally called bipolar plates because they serve as the positive and negative electrodes of adjacent units in multistage series connection, and the bipolar plates also serve to separate oxyhydrogen gas. Complex flow channels are engraved on the bipolar plate. Since the flow channels on a bipolar plate are typically elongated and narrow (the flow channels are typically non-through grooves about 1mm wide, not more than 1mm deep), the process of either engraving or electroetching is very difficult. In view of the above, the inventors of the present application have made a long-term study and have proposed an improvement.

Please refer to fig. 1 to 11.

Example one

As shown in fig. 1 to 11, the present invention provides an pem water electrolyzer 100, which comprises a membrane electrode 1, an end plate 2, a positive electrode flow field assembly and a negative electrode flow field assembly, the anode flow field assembly and the cathode flow field assembly are positioned at two opposite sides of the membrane electrode 1, the end plates 2 are respectively positioned at one ends of the anode flow field assembly and the cathode flow field assembly which are far away from the membrane electrode 1, that is, the end plates 2 are two, referring to fig. 2, the two end plates 2 can be respectively defined as an upper end plate and a lower end plate, the membrane electrode 1, the positive flow field assembly and the negative flow field assembly are arranged between the two end plates 2, and the upper end plate, the positive flow field assembly, the membrane electrode 1, the negative flow field assembly and the lower end plate can be sequentially stacked and then locked by bolts to form the structure shown in fig. 1, of course, in other examples, the structures may be fixed by other methods, which is not limited strictly; at least one end plate 2 is provided with openings for discharging gas and water, in this embodiment, the upper end plate (i.e. the end plate located at the uppermost portion) is provided with openings for water and gas to enter and exit, for example, a first opening for discharging hydrogen and water to enter and exit and a second opening for discharging oxygen and water to enter and exit ("first" and "second" are merely for convenience of description and have no substantial limiting meaning), and the first opening and the second opening may be single or two or more, while the lower end plate adjacent to the negative flow field assembly is not provided with openings for water and gas to enter and exit, the positive flow field assembly and the negative flow field assembly are provided with flow guide holes communicated with the openings, and the positive flow field assembly and the negative flow field assembly are provided with a diffusion structure layer, a bipolar plate 43/53, a flow channel sealing gasket 45/55 and a flow channel plate 44/54 in a direction away from the membrane electrode (these structures are usually sequentially arranged, that is, the diffusion structure layer is adjacent to the membrane electrode 1, the bipolar plate 43/53 is located between the diffusion structure layer and the flow path sealing gasket 45/55, the flow path sealing gasket 45/55 may have a structure with a receiving groove inside, the flow path plate 44/54 is correspondingly located inside the flow path sealing gasket 45/55, and the flow path sealing gasket may be used to prevent water leakage, wherein the bipolar plate 43 is provided with a through groove 432 (i.e., the groove penetrates through the bipolar plate), and of course, a flow guide hole 431, the flow path plate 44 is provided with a through groove 441 (i.e., the groove penetrates through the flow path plate 44), a non-penetrating shallow groove 442 (i.e., the groove does not penetrate through the flow path plate 44), and a communicating narrow groove 443 for communicating the through groove 441 and the shallow groove 442 of the flow path plate 44 with the flow guide hole 444, the through groove 441 of the bipolar plate 43/53, the through groove 441, the shallow groove 442, and the flow path plate 44/54, and the flow guide hole 444 are communicated with the flow guide hole, The communicating narrow grooves 443 are communicated with each other to form a water storage and air discharge cavity, that is, the water storage and air discharge cavity is communicated with the flow guide holes through the communicating narrow grooves of the flow passage plate to realize water and air circulation.

The exemplary operation process of the pem water electrolyzer 100 provided in this embodiment is, as shown in fig. 3, placing the electrolyzer horizontally during operation with the anode (oxygen evolution side) on top, multiple (e.g. 4) water vapor inlets and outlets of the electrolyzer directly communicating with the water tank, placing the water tank 8 above the electrolyzer, the water tank 8 may include a hydrogen tank 81 and an oxygen tank 82, the two tanks may be separated by a plate with a communication hole 83, and the communication hole is provided to facilitate water level balance; when direct current voltage is applied to the bipolar plate, hydrogen and oxygen are respectively separated out from two sides of the membrane electrode 1 coated with the catalyst, and the separated hydrogen and oxygen rapidly pass through a loose current collector (oxygen passes through the current collector 41 of the anode flow field assembly, and hydrogen passes through the current collector 51 of the cathode flow field assembly), enter a water storage and exhaust cavity formed by a through groove 441 (which can also be defined as a flow guide groove, and only the flow guide groove passes through the bipolar plate) on the bipolar plate and the through groove, the shallow groove and the communicated narrow groove of the flow channel plate, and are discharged into a water tank from an inlet and an outlet. The through-groove volume of the bipolar plate can be made sufficiently large by adjusting the thickness of the flow channel plate or the bipolar plate, so that the exhaust gas has sufficient buffer storage space. As shown in fig. 4, the water entering the anode side of the electrolytic cell from the water tank 8 is retained at the lower part of the water storage and exhaust cavity under the combined action of gravity and the pressure of the precipitated oxygen, so that the oxygen evolution surface of the whole membrane electrode 1 is always soaked in the water, and the electrolytic reaction is more uniformly distributed on the membrane surface; the structure of the water storage and air exhaust cavity at the hydrogen evolution side is similar to that at the oxygen evolution side. Referring to fig. 2, since the through grooves and the flow guiding holes are staggered when the positive flow passage plate and the negative flow passage plate are stacked, only the oxygen of the positive electrode or the hydrogen of the negative electrode can be communicated on the same common pipeline, thereby realizing the discharge of the hydrogen and the oxygen from different pipelines respectively (refer to fig. 4).

Although water is not needed to be supplemented on the hydrogen evolution side, the water storage and exhaust cavity is also arranged on the hydrogen evolution side, so that the reaction heat can be effectively taken away by utilizing the flow of water, the membrane electrode is prevented from being overheated and losing efficacy, and the service life of the membrane electrode is prolonged. The utility model adds a flow passage plate behind the bipolar plate, the flow passage plate is carved with a through groove, the flow guide groove penetrating the bipolar plate and the through groove on the flow guide plate form a large-volume water storage and exhaust cavity together, which can greatly improveThe efficiency of water-gas exchange between the electrolytic cell and the outside provides good conditions for water flow heat dissipation and gas discharge. Compared with the structure of a non-through groove in the prior art, the through groove forming the water storage and exhaust cavity can be processed in various modes such as laser cutting, ion cutting, water jet cutting, linear cutting and the like, a 100-square-centimeter flow field (0.5mm wide flow channel) needs 10 hours by a CNC high-speed machine tool, the flow field structure can be processed by laser after 2 minutes, the processing efficiency is greatly improved, the processing cost is reduced, the flow channel plate can be obtained by an injection molding mode, the width and the depth of the through groove on the flow channel plate can be far larger than those of a flow channel carved on the traditional polar plate, and therefore the flow resistance can be greatly reduced. The utility model is different from the traditional vertical arrangement mode, the electrolytic tank is horizontally arranged in a mode that the bipolar plate is parallel to the ground, the anode oxygen evolution surface is arranged on the upper part of the electrolytic tank, the water tank is arranged on the upper part of the electrolytic tank and is directly connected with the electrolytic tank, the separated gas can naturally rise to enter the water storage and exhaust cavity during operation, and the pure water is left at the bottom of the water storage and exhaust cavity under the combined action of gravity and air pressure, so that the membrane electrode is soaked in the pure water at every moment, the problem of water shortage of the membrane electrode is thoroughly solved, the pumpless operation of the electrolytic tank is realized, the system complexity is greatly simplified, and the system reliability is improved. The water electrolyzer with the proton exchange membrane provided by the utility model is adopted to realize 2A cm under the pump-free condition^–2Is in stable operation for thousands of hours at the current density of (c).

As shown in fig. 5 to 6, two flow guide holes 431 for air and water to flow in and out are respectively disposed on two opposite sides of the bipolar plate 43, and the hole diameters of the flow guide holes 431 may be the same or different. As shown in fig. 5, in one example, the through grooves 432 of the bipolar plate 43 may be distributed in a comb shape, that is, a plurality of through grooves 432 form a comb structure, and the through grooves 432 on the same comb structure are communicated with each other. As can be seen with reference to fig. 5, a plurality of parallel through grooves 432 are connected to a through groove perpendicular thereto to form a comb structure, so that one end of the parallel through grooves 432 is a free end (i.e. has a certain flexibility), which allows the portion of the bipolar plate 43 corresponding to the through groove 432 to swing back and forth in a vertical plane, which facilitates the compression fixation of the whole electrolytic cell, especially the bipolar plate and the membrane electrode 1. In addition, it should be noted that, in the embodiment, although only one comb tooth structure is illustrated, the utility model is not limited thereto. If the comb tooth structure is applied to an oversize electrolytic tank, the comb tooth structure is too large to be processed and installed, the bipolar plate can be split at the moment, for example, the bipolar plate is divided into a plurality of electrodes with the size of a square meter, the number of through grooves can be thousands, and the through grooves can be arranged into a plurality of comb tooth structures so as to improve the structural stability. When the through-grooves of the comb tooth structure design are used, the tooth width h of the through-grooves on the same comb tooth structure is preferably 0.1 to 3mm, such as 0.1mm, 1mm, 2mm, 3mm or any value in this interval, and the groove width d of the through-grooves (i.e., the dimension shown in fig. 5 is 0.5 to 5mm, such as 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm or any value in this interval).

In another example, as shown in fig. 6, a plurality of through slots 432 of the bipolar plate 43 are interconnected in a serpentine arrangement, or the bipolar plate 43 can be described as including a single through slot 432 in a serpentine arrangement. In this embodiment, the tooth width d of the through slot is also preferably 0.5 to 5mm, and the slot width h of the through slot is preferably 0.1 to 3 mm.

The bipolar plate 43 in fig. 5 and 6 has a different structure of the through groove 432, but the design of the flow guiding holes 431 is the same, so that the flow field structure is the same when the through groove is applied to the electrolytic cell of the present embodiment, and reference can be made to fig. 3 and 4.

It should be noted that, although only the bipolar plate of the positive flow field assembly is taken as an example in this embodiment, the bipolar plate structure of the negative flow field assembly may be identical to that of the positive flow field assembly, and the thickness of the bipolar plate of the positive flow field assembly and the thickness of the bipolar plate of the negative flow field assembly (i.e., the depth of the through groove) may be identical or different.

As shown in fig. 7 and 8, in the present embodiment, the through grooves 441 and the shallow grooves 442 of the flow channel plate 44 intersect and communicate with each other, and are connected to the guide holes 441 by the communication narrow grooves 443, thereby communicating with the openings in the end plates. More specifically, the through grooves 441 and the shallow grooves 442 extend in directions perpendicular to each other, and the through grooves 441 of the flow field plate 44 may extend in directions parallel to and vertically corresponding to the through grooves 432 of the bipolar plate 43, for example. Through such design, help reducing the fluid resistance, make the aqueous vapor flow more smoothly.

It should also be noted that, although only the flow channel plate of the positive flow field assembly is taken as an example in this embodiment, the flow channel plate structure of the negative flow field assembly may be identical to that of the positive flow field assembly, and the thickness of the flow channel plate of the positive flow field assembly and the thickness of the flow channel plate of the negative flow field assembly (i.e., the thickness of the through groove 441) may be identical or different.

Illustratively, the diffusion structure layer includes a current collector gasket 42/52 and a current collector 41/51. The current collector gasket 42/52 is, for example, a silicone flexible mat, and the current collector 41/51 is, for example, a titanium felt or a titanium mesh, and serves to uniformly distribute electric charge throughout the membrane electrode 1 and reduce contact resistance.

The material of the flow channel sealing gasket and the flow channel plate is usually a non-titanium cheap material, i.e. a non-titanium material plate, and the flow channel plate is preferably made of a rigid material, i.e. a rigid material plate, e.g. a ceramic material plate, but not limited thereto, i.e. other materials may be used.

In an example, a membrane electrode compensation pad 6 is further disposed between the membrane electrode 1 and the negative electrode flow field assembly, an accommodating groove may be disposed inside the membrane electrode compensation pad 6, and the membrane electrode 1 is embedded in the accommodating groove of the membrane electrode compensation pad 6.

In an example, the pem water electrolyzer 100 further includes a blind plate (not shown) for preventing the end plate 2 from polluting water, and is located between the negative electrode flow field assembly and the end plate 2 (i.e. the blind plate is adjacent to the end plate at the bottom end), the blind plate is a plane plate without flow guide holes on the surface as the name suggests, the material of the blind plate can be an insulating material with a smooth surface, and the end plate 2 (i.e. the lower end plate) at one end of the negative electrode flow field assembly is prevented from polluting water by contacting water by the blind plate.

In one example, the positive and negative flow field assemblies may both be single, while in another example, as shown in fig. 9-11, the positive and negative flow field assemblies may both be multiple; when the number of the unit partition plates is multiple, the proton exchange membrane water electrolyzer also comprises a plurality of unit partition plates 3, the anode flow field assemblies and the cathode flow field assemblies are alternately arranged to form a plurality of electrolytic water units A which are mutually connected in series (a single electrolytic water unit comprises one anode flow field assembly and one cathode flow field assembly), the unit partition plates 3 are provided with flow guide holes, the unit partition plates 3 do not participate in electric conduction, and the adjacent electrolytic water units A are subjected to gas separation through the unit partition plates 3; the unit partition plates 3 are used for separating hydrogen from oxygen and do not participate in electrolytic conduction, and therefore, the unit partition plates can be made of insulating materials, such as polyethylene plates and other polymer material plates, and of course, the unit partition plates can be made of other materials as long as the unit partition plates do not participate in the conduction in the water electrolysis process. The specific structures of the anode flow field assembly and the cathode flow field assembly are the same as those described above, and please refer to the foregoing description for brevity. The plurality of water electrolysis units are connected in series, so that the water electrolysis efficiency is improved, the system structure is further simplified, the occupied space of the electrolytic cell is reduced, and the electrolysis cost is reduced.

In the case of a plurality of the electrolytic water units a, in a further example, the proton exchange membrane water electrolyzer further comprises a conductive sheet 7, the bipolar plate of each electrolytic water unit extends outwards, so that after the structures are pressed and fastened, the outwards extending part of the bipolar plate is connected/contacted with the conductive sheet 7 to realize electric connection, and the conductive sheet includes but is not limited to a copper sheet. The design is beneficial to improving the convenience of assembling and disassembling the proton exchange membrane water electrolyzer. Of course, in other examples, the water electrolysis units may be connected in series through wires, or the bipolar plates of the water electrolysis units extend outwards and are welded two by two to achieve electric conduction, which is not limited strictly.

Although the oxyhydrogen outlet is arranged on the same side in the schematic diagram of the embodiment, in practice, the water inlet + oxyhydrogen outlet can be arranged on both the upper end plate 2 and the lower end plate 2, and in this case, the blind plate needs to be replaced by the unit partition plate 3 provided with the diversion holes.

The utility model also provides a water electrolysis system of the proton exchange membrane. Referring to fig. 3, the proton exchange membrane water electrolysis system comprises a water tank 8 and the proton exchange membrane water electrolysis cell 100 as described in any one of the above embodiments, wherein the proton exchange membrane water electrolysis cell 100 is horizontally placed below the water tank 8 with the positive electrode oxygen evolution surface facing upwards, and is communicated with the water tank 8. The water tank 8 includes, for example, a hydrogen tank 81 and an oxygen tank 82, which may be spaced apart by a plate provided with a communication hole 83 for facilitating water level balance. As shown in fig. 3, the water entering the anode side of the electrolytic cell from the water tank 8 is retained at the lower part of the water storage and exhaust cavity under the combined action of gravity and the pressure of the precipitated oxygen, so that the oxygen evolution surface of the whole membrane electrode 1 is always soaked in the water, and the electrolytic reaction is more uniformly distributed on the membrane surface; the structure of the water storage and air exhaust cavity at the hydrogen evolution side is similar to that at the oxygen evolution side. Although water is not needed to be supplemented on the hydrogen evolution side, the water storage and exhaust cavity is also arranged on the hydrogen evolution side, so that the reaction heat can be effectively taken away by utilizing the flow of water, the membrane electrode is prevented from being overheated and losing efficacy, and the service life of the membrane electrode is prolonged. For more description of the proton exchange membrane water electrolyzer, please refer to the foregoing, and for brevity, the description is omitted. The proton exchange membrane water electrolysis system provided by the embodiment adopts the proton exchange membrane water electrolysis cell, so that continuous water electrolysis operation can be realized without using a pump, namely the proton exchange membrane water electrolysis system provided by the embodiment has no pump.

The proton exchange membrane water electrolysis method carried out by the proton exchange membrane water electrolysis cell comprises the steps of horizontally placing the proton exchange membrane water electrolysis cell in any scheme below a water tank in a mode that the positive electrode oxygen evolution surface faces upwards (namely, adopting the proton exchange membrane water electrolysis system), communicating a water-gas inlet and a water tank of the proton exchange membrane water electrolysis cell, and realizing continuous water electrolysis operation under the condition of no pump. Specifically, as shown in fig. 3, water entering the anode side of the electrolytic cell from the water tank 8 is retained at the lower part of the water storage and exhaust cavity under the combined action of gravity and the pressure of the separated oxygen, after a direct current voltage is applied to the bipolar plate, hydrogen and oxygen are separated out from both sides of the membrane electrode 1 coated with the catalyst at this time, the separated hydrogen and oxygen rapidly pass through the loose current collector (oxygen passes through the current collector 41 of the anode flow field assembly, and hydrogen passes through the current collector 51 of the cathode flow field assembly), enter the water storage and exhaust cavity formed by the through grooves on the bipolar plate, the through grooves of the flow passage plate, the shallow grooves, the communicating narrow grooves and the gaps between the bipolar plate and the flow passage plate, and are discharged into the water tank from the inlet and the outlet to realize continuous water electrolysis operation in a pump-free state. The water electrolysis method of the proton exchange membrane provided by the embodiment adopts the water electrolysis tank of the proton exchange membrane, so that the overheating of the membrane electrode can be effectively avoided, a pump is not needed, the electrolysis cost can be reduced, and the electrode efficiency can be improved.

In summary, the present invention provides a water electrolyzer with proton exchange membrane and a system thereof. The electrolytic bath comprises a membrane electrode, end plates, an anode flow field assembly and a cathode flow field assembly, wherein the anode flow field assembly and the cathode flow field assembly are positioned at two opposite sides of the membrane electrode, the end plates are respectively positioned at one ends of the anode flow field assembly and the cathode flow field assembly, which are deviated from the membrane electrode, at least one end plate is provided with an opening for discharging gas and water, the anode flow field assembly and the cathode flow field assembly are respectively provided with a flow guide hole communicated with the opening, and the anode flow field assembly and the cathode flow field assembly are provided with a diffusion structure layer, a bipolar plate, a flow channel sealing gasket and a flow channel plate along the direction far away from the membrane electrode, wherein the bipolar plate is provided with a through groove, a non-through shallow groove and a communication narrow groove for communicating the through groove and the shallow groove of the flow channel plate with the flow guide hole, a gap is arranged between the bipolar plate and the flow passage plate, and the through groove of the bipolar plate, the through groove of the flow passage plate, the shallow groove, the communicating narrow groove, the flow passage plate and the gap between the bipolar plate are communicated with each other to form a water storage and exhaust cavity. Through the improved structural design, the processing difficulty of the flow field structure of the water electrolysis bath can be greatly reduced, the processing cost is reduced, the smoothness of water flow in the electrolysis bath can be obviously improved, the phenomenon of water shortage and overheating of a membrane electrode is avoided, the service life of the electrolysis bath is prolonged, the complexity of a system is reduced, and the pumpless operation of a large proton exchange membrane water electrolysis bath is realized. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (11)

1. A water electrolyzer with proton exchange membrane is prepared as setting positive and negative flow field components at two opposite sides of membrane electrode, setting end plate at one end of said positive and negative flow field components separately, setting opening for exhausting gas and water in and out on at least one end plate, setting flow guide holes on said positive and negative flow field components and setting diffusion structure layer, double polar plate, flow channel sealing pad and flow channel plate on said double polar plate, setting through slot on said plate and through slot, non-through shallow slot on said flow channel plate and through narrow slot for connecting through slot and shallow slot on said flow channel plate with flow guide holes, a gap is arranged between the bipolar plate and the flow passage plate, and the through groove of the bipolar plate, the through groove of the flow passage plate, the shallow groove, the communicating narrow groove, the flow passage plate and the gap between the bipolar plate are communicated with each other to form a water storage and exhaust cavity.

2. The proton exchange membrane water electrolyzer of claim 1, wherein the through-grooves and the shallow grooves of the flow channel plate are arranged crosswise and communicate with each other.

3. The pem water electrolyzer of claim 1 wherein said plurality of through-slots of said bipolar plate form a comb-tooth structure, the through-slots on the same comb-tooth structure communicating with each other.

4. The PEM water electrolyzer of claim 3 characterized in that the through grooves on the same comb tooth structure have a tooth width of 0.1-3mm and a groove width of 0.5-5 mm.

5. The pem water electrolyzer of claim 1 wherein said plurality of through-channels of said bipolar plates are interconnected and distributed in a serpentine pattern.

6. The pem water electrolyzer of claim 1 wherein said diffusion structure layer comprises a current collector and a current collector gasket, and a membrane electrode gasket is disposed between said membrane electrode and said negative flowfield assembly.

7. The pem water electrolyzer of claim 1 wherein said flow-channel gasket and flow-channel plate are non-titanium plates and said flow-channel plate is a rigid plate.

8. The pem water electrolyzer of any one of claims 1 to 7, wherein said pem water electrolyzer comprises a plurality of positive flow field assemblies, negative flow field assemblies and unit separators, wherein the positive flow field assemblies and the negative flow field assemblies are alternately arranged to form a plurality of series-connected electrolyzed water units, the unit separators are provided with diversion holes, the unit separators do not participate in electric conduction, and adjacent electrolyzed water units are separated by gas through the unit separators.

9. The pem water electrolyzer of claim 8 further comprising an electrically conductive sheet, the bipolar plates of each electrolyser cell extending outwardly into electrical connection with said electrically conductive sheet.

10. The pem water electrolyser of claim 8 wherein the bipolar plates of each electrolyser cell extend outwardly and are welded two by two for electrical conduction.

11. A pem water electrolysis system comprising a water tank and a pem water electrolyzer as claimed in any of claims 1-10, said pem water electrolyzer being horizontally placed under said water tank with the anode oxygen evolving side up and communicating with said water tank.

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