A plate and flow field with dual functions of water supply and cooling for pure water SPE electrolyzer

Abstract

The present invention discloses a plate and flow field for a pure water SPE electrolyzer with dual functions of water supply and cooling. The plate material is selected from graphite plates or metal plates, and the anode flow field design adopts a single-channel or multi-channel serpentine flow field. Each flow field channel serpentines from the fluid inlet of the anode to the anode outlet. When the fluid passes through, the fluid follows the serpentine channel and covers the entire anode surface, so that the anode plate fluid of the electrolyzer is fully in contact with the thin film electrode, achieving stable water supply, thereby stabilizing the electrolysis and realizing effective cooling of the electrode. The cathode adopts a fence-type parallel channel design, and the generated hydrogen can be quickly discharged from the cathode outlet and take away part of the heat. A fixed groove is set on the edge of the plate, which is convenient for the assembly of the plate and the membrane electrode and the expansion of the electrolyzer. The SPE electrolyzer using the plate and flow field can significantly improve the electrolysis performance of the electrolyzer and achieve effective temperature control under the same current density.

Description

Technical Field

[0001] The invention relates to the technical field of pure water solid polymer electrolyte (SPE) electrolysis hydrogen production, and in particular to an electrode plate and a flow field with dual functions of water supply and cooling for a pure water SPE electrolyzer. Background Art

[0002] Pure water SPE electrolysis hydrogen production technology refers to the technology of producing hydrogen by electrolysis of pure water in a water electrolyzer. Since a solid polymer membrane is used as an electrolyte, there is no need to add alkali or acid as an electrolyte. Usually, the catalyst is bonded to the positive and negative sides of the solid polymer electrolyte to form the anode and cathode of the electrode. The thin film electrode is placed between two plates (anode and cathode), and water can be decomposed by powering on, obtaining hydrogen at the cathode and oxygen at the anode.

[0003] During the electrolysis of pure water, pure water can be evenly and fully supplied to every area of ​​the electrode, which is very important for improving the efficiency of the water electrolyzer and achieving a long life of the electrode; at the same time, the circulation of pure water on the anode side is also an effective way to achieve effective cooling of the electrodes and batteries and battery temperature control.

[0004] The plate and flow field design of the water electrolyzer directly affects the sufficient supply of pure water, the effective contact between the membrane electrode and pure water, the timely discharge of oxygen and hydrogen, and the effective cooling of the water electrolyzer, thus affecting the electrolysis performance of the water electrolyzer. Usually, the following requirements need to be met in the design of the plate and flow field:

[0005] 1. There is a small pressure drop at the inlet and outlet of pure water, which can reduce the performance requirements of the peripheral equipment of the electrolyzer and effectively reduce energy consumption, such as the use of a low-power liquid pump.

[0006] 2 The flow field channels of the anode plate flow field, cathode plate flow field, anode flow field inlet, anode flow field outlet, and cathode flow field outlet of the water electrolyzer are reasonably arranged, which can not only achieve stable water supply to ensure stable electrolysis, but also realize effective cooling of the electrodes to prevent damage caused by excessive temperature.

[0007] 3 The plates and hydrogen and oxygen sides of the flow field of the water electrolyzer should be isolated to prevent the mixing of the generated hydrogen and oxygen gases, thereby ensuring the safety of the SPE water electrolyzer and the purity of the hydrogen.

[0008] 4 The plates and flow field of the water electrolyzer must ensure the independence of each plate, and the number of plates can be increased or decreased as needed without affecting the overall structural performance of the water electrolyzer.

[0009] In the case of a large amount of airflow, the current plate and flow field design often cannot ensure the uniform distribution and sufficient supply of pure water on the electrode surface, resulting in "blank areas" on the electrode surface, which seriously reduces the electrolysis efficiency of the electrode and the electrolytic cell. On the other hand, the water flow on the anode side of the current electrolyzer often also plays the role of a cooling medium, taking out the heat in the electrolytic cell through the circulation of water. However, in the current flow field design, the water flow cannot flow evenly through the entire electrode, resulting in a large number of stagnation areas, so that the electrode cannot be evenly and effectively cooled, resulting in a decrease in the performance of the electrolytic cell.

[0010] Chinese invention patent 105839136 A discloses a centrosymmetric radial bipolar plate flow field structure for SPE electrolysis. However, in the case of a large amount of gas generated in this flow field, the gas cannot be discharged in a timely and effective manner; the occupation of the gas hinders the uniform distribution of pure water on the electrode surface, forming a "blank area", which in turn affects the effective heat dissipation of the electrode. Chinese invention patent 103806014A adopts an improved parallel flow field elbow design to improve flow field heat dissipation, but it also has the defect that the pure water cannot be evenly distributed on the electrode surface due to the inability to discharge the generated gas in a timely manner. Summary of the invention

[0011] In view of the shortcomings of the existing flow field, the present invention proposes a plate and a flow field for a pure water SPE electrolyzer that has both water supply and cooling functions.

[0012] The present invention discloses the technical solution as follows.

[0013] The anode flow field design in the present invention adopts a single-channel or multi-channel serpentine channel flow field design, and each flow field channel extends from the anode fluid inlet to the anode outlet in a serpentine shape. When the fluid passes through, the fluid follows the serpentine channel and covers the entire anode surface, so that the anode fluid of the water electrolyzer is fully in contact with the anode of the thin film electrode for electrolysis reaction, thereby achieving stable water supply, and taking away the heat generated during the electrolysis process, preventing local overheating of the electrode, and achieving effective cooling of the electrode, thereby making the electrolysis of the water electrolyzer stable. The cathode adopts a fence-type parallel channel design, and the generated hydrogen can be quickly discharged from the cathode outlet, while taking away part of the heat generated by the electrolysis.

[0014] A plate and flow field for a pure water SPE electrolyzer with dual functions of water supply and cooling, the plate is a monopolar plate or a bipolar plate (i.e. one side is an anode and the other side is a cathode); the plate material is stainless steel, titanium plate or graphite plate; the plate surface includes: an anode cathode flow field, a fluid inlet, an anode outlet, a cathode outlet sealing surface and a fixing screw hole; the anode cathode flow field includes an anode flow field and a cathode flow field; the anode fluid has the functions of supplying and cooling the electrolytic raw material (water) (taking out the heat generated in the electrolytic cell through the fluid), and the anode flow field adopts a single-channel or multi-channel serpentine The cathode flow field adopts a fence design; the overall design of the electrode plate is circular, and a fixing screw hole is set on the edge of the electrode plate. In addition to the designed flow field, a fluid inlet, an anode outlet, and a cathode outlet are also set on the surface of the electrode plate. The flow field is arranged in the middle of the front and back sides of the electrode plate, and the anode fluid inlet and anode outlet are arranged on both sides of the anode flow field, which are symmetrically distributed. The cathode outlet is arranged on the side of the cathode electrode plate, and is staggered with the anode fluid inlet and anode outlet; the anode outlet is connected to the anode flow field through a connecting channel, and the cathode outlet is connected to the cathode flow field through a connecting channel.

[0015] Furthermore, the anode flow field adopts a single-channel or multi-channel full-domain serpentine design, and each channel runs through the entire electrode plate, ensuring the effective supply of raw water to the thin film electrode when a large amount of gas is generated, and the effective removal of the large amount of heat generated at the anode.

[0016] Furthermore, the cathode flow field adopts a fence flow field design, which can ensure that the generated hydrogen can be discharged in time and take away some heat.

[0017] Furthermore, the cathode outlet is arranged at one end of the cathode flow field parallel fence-shaped groove, and is staggered with the anode inlet and outlet. The cathode outlet is separated from the anode fluid inlet and the anode outlet by a plate seal.

[0018] Furthermore, the anode plate fluid flow field and the cathode plate fluid flow field are arranged on both sides of the plate.

[0019] The electrode plate and flow field designed as above are used in a pure water SPE electrolyzer, which has stable water supply and can achieve effective temperature control, so that the overall performance of the pure water SPE electrolyzer is stable.

[0020] It also has the following advantages:

[0021] 1. There is a small pressure drop at the inlet and outlet of pure water, which reduces the performance requirements for the peripheral equipment of the electrolyzer and can effectively reduce energy consumption;

[0022] 2. It can effectively isolate the generated hydrogen and oxygen, ensure the safety of the SPE water electrolyzer, and also ensure the purity of the output hydrogen.

[0023] 3. Convenient expandability: The independent design of the electrode plate and the flow field ensures the convenient expandability of the water electrolyzer. The number of electrode plates can be easily increased or decreased as needed without affecting the overall structural performance of the water electrolyzer.

[0024] 4. The water supply on the anode side is stable and uniform, which ensures uniform hydrogen production at the electrode; there is no dead corner in the water flow, which can effectively and evenly cool the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the assembly of the electrode plate and flow field of a pure water SPE electrolyzer for taking into account both water supply and cooling functions of the present invention;

[0026] Figure 2 The schematic diagram of the decomposition of the electrode plate and flow field of a pure water SPE electrolyzer for both water supply and cooling of the present invention is shown in FIG.

[0027] Figure 3 A schematic diagram of an anode flow field of a pure water SPE electrolyzer for both water supply and cooling according to the present invention;

[0028] Figure 4 The diagram is a schematic diagram of the cathode flow field of the electrode plate and flow field of a pure water SPE electrolyzer for combining the dual functions of water supply and cooling according to the present invention.

[0029] The components in the figure are as follows: anode monopolar plate 1, seal 2, thin film electrode 3, bipolar plate electrode 4, cathode monopolar plate 5. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0031] A pure water SPE electrolyzer with dual functions of water supply and cooling, with a plate and flow field (see the attached diagrams of the anode and cathode flow fields, respectively) Figure 3 and attached Figure 4 ), and an electrolyzer formed by assembling the electrode plate and flow field of the present invention (the assembly diagram and the exploded diagram are respectively shown in the attached Figure 1 and attached Figure 2 ).

[0032] The plates can be made of graphite, stainless steel and titanium plates. For monopolar plates, the anode plate is provided with a "fluid inlet hole", "anode outlet" and a "fixing screw hole" for the battery stack assembly, and the "anode flow field" is designed and processed on one side of the plate; the cathode plate is provided with a "cathode outlet" and a "fixing screw hole", and the "cathode flow field" is designed and processed on one side of the plate; for bipolar plates, in addition to providing the "fluid inlet hole", "anode outlet", "cathode outlet" and a "fixing screw hole" for the battery stack assembly on the plate, it is also necessary to design and process the anode flow field and cathode flow field on both sides of the plate respectively;

[0033] Figure 3 It is a schematic diagram of a serpentine single-channel anode plate and flow field (the anode flow field can be a single-channel serpentine flow field or a parallel multi-channel serpentine flow field). The plate shape is designed to be circular (not limited to a circle), and 5-6mm from the plate boundary is used to set the "fluid inlet hole", "anode outlet" and "fixing screw hole" (that is, no flow field is set 5-6mm from the plate boundary). The anode fluid inlet and anode outlet are set on both sides of the plate, symmetrically distributed, and 10 "fixing screw holes" are symmetrically set. The flow field is designed in the middle of the plate, with a flow groove width of 2mm, a flow groove depth of 2mm, a rib width of 1.5mm, and a groove-rib ratio of the "anode flow field" of about 4;3; The anode fluid inlet and anode outlet are connected by grooves, and the flow channel extends from the anode fluid inlet to the outlet; when the electrolytic cell is working, pure water can be evenly supplied to the entire active area of ​​the membrane electrode, realizing efficient water supply and effective cooling of the electrolytic cell;

[0034] Figure 4 This is a schematic diagram of the cathode plate and flow field. The cathode does not need to introduce fluid, so no fluid inlet is designed. The plate shape is designed to be circular (not limited to circular), and 5-6mm from the plate boundary is used to set the "cathode outlet" and "fixing screw hole" (that is, no flow field is set 5-6mm from the plate boundary). The cathode outlet is set to be staggered with the anode fluid inlet and anode outlet, so that the cathode outlet is isolated from the anode fluid inlet and anode outlet; at the same time, 10 "fixing screw holes" are symmetrically set (matching the anode plate fixing screw holes). The flow field is designed in the middle of the plate. The cathode flow field adopts a parallel fence flow field, the direction points to the cathode outlet, the flow groove width is 2mm, the depth is 1mm, the rib width is 1.5mm, and the groove-rib ratio of the "cathode flow field" is about 4;3. A guide groove is set around the fence flow field, which is connected to the cathode outlet to gather the hydrogen produced by the cathode and discharge it from the cathode outlet.

[0035] A typical water electrolyzer assembled by using the plates of the flow field designed by the present invention comprises: an anode end monopolar plate 1 and a cathode end monopolar plate 5, and a plurality of anode and cathode bipolar plates 4 can be arranged between the anode end monopolar plate 1 and the cathode end monopolar plate 5 as required. The thin film electrode 3 is placed between the anode and cathode of two (single, double) polar plates (such as: between the anode side of the bipolar plate 4 and the cathode side of the cathode monopolar plate, the anode side of the anode monopolar plate 1 and the cathode side of the bipolar plate 4, etc.), and a sealing ring is added to assemble into an electrolytic cell stack containing a single electrolytic cell of one or more electrodes.

Claims

1. A plate with dual functions of water supply and cooling for a pure water SPE electrolyzer, characterized in that: The plate is a bipolar plate; the plate material is stainless steel, titanium plate or graphite plate; the plate surface includes: an anode flow field, a cathode flow field, an anode fluid inlet, an anode outlet, a cathode outlet sealing surface and a fixing screw hole; the anode flow field adopts a single-channel or multi-channel serpentine design; the cathode flow field adopts a fence design; the plate is designed as a circle as a whole, and a fixing screw hole is arranged on the edge of the plate. In addition to designing and processing the anode flow field and the cathode flow field, the plate surface is also provided with a fluid inlet, an anode outlet and a cathode outlet; the anode flow field and the cathode flow field are both arranged in the middle of the front and back sides of the plate, the anode fluid inlet and the anode outlet are arranged on both sides of the anode flow field, and are symmetrically distributed, and the cathode outlet is arranged on the side of the cathode plate, and is staggered with the anode fluid inlet and the anode outlet; the anode outlet is connected to the anode flow field through a connecting channel, and the cathode outlet is connected to the cathode flow field through a connecting channel; The anode flow field adopts a single-channel or multi-channel full-domain serpentine design, and each channel runs through the entire electrode plate; the electrode plate is designed to be circular in shape, and 5-6mm away from the electrode plate boundary is used to set the fluid inlet, the anode outlet and the fixing screw hole, that is, the flow field is not set 5-6mm from the electrode plate boundary, and the anode fluid inlet and the anode outlet are set on both sides of the electrode plate, symmetrically distributed, and 10 fixing screw holes are symmetrically set at the same time; the flow field is designed in the middle of the electrode plate, the flow groove width is 2mm, the flow groove depth is 2mm, the rib width is 1.5mm, and the groove-rib ratio of the anode flow field is 4:3; the anode fluid inlet and the anode outlet are connected through the groove, and the flow channel extends from the anode fluid inlet to the outlet; when the electrolytic cell is working, pure water is evenly supplied to the entire active area of ​​the membrane electrode, realizing efficient water supply and effective cooling of the electrolytic cell; The cathode plate is designed to be circular in shape, and 5-6 mm from the plate boundary is used to set the cathode outlet and the fixing screw hole, that is, no flow field is set 5-6 mm from the plate boundary; 10 fixing screw holes are symmetrically set at the same time, and the fixing screw holes are consistent with the fixing screw holes of the anode plate; the flow field is designed in the middle of the plate, and the cathode flow field adopts a fence flow field design; the cathode flow groove is 2 mm wide, 1 mm deep, and 1.5 mm wide, and the groove-rib ratio of the cathode flow field is 4:3; a guide groove is set around the fence flow field, which is connected to the cathode outlet to gather the hydrogen generated by the cathode and discharge it from the cathode outlet; The cathode outlet is arranged at one end of the cathode flow field parallel to the fence-shaped groove, and is staggered with the anode inlet and outlet; The anode plate fluid flow field and the cathode plate fluid flow field are arranged on both sides of the plate.

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