Photovoltaic direct coupling water electrolysis device and method

Abstract

This invention discloses a photovoltaic direct-coupled water electrolysis device, comprising a photovoltaic unit, a water electrolysis unit, and a liquid circulation auxiliary unit. The photovoltaic unit includes a solar cell and wires; the water electrolysis unit includes an anode clamp, an anode flow channel, an anode electrode, a diaphragm, a cathode electrode, a cathode flow channel, and a cathode clamp; the solar cell and the anode clamp are tightly attached together; the photovoltaic unit supplies power to the water electrolysis unit. This invention achieves a close fit between the solar cell and the anode clamp, simultaneously reducing the temperature of the solar cell and increasing the temperature of the electrolyte during operation, thereby improving the operating efficiency of the solar cell and the electrolyzer, and realizing efficient solar-driven alkaline water electrolysis.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, specifically to a photovoltaic direct-coupled water electrolysis device and method. Background Technology

[0002] Hydrogen, as an energy carrier, has extremely broad application prospects, especially playing a crucial role in promoting the sustainable energy transition. Water electrolysis is one of the key methods for producing hydrogen. It decomposes water into hydrogen and oxygen by applying an electric current. If the electricity used in this process comes from renewable energy sources, such as wind or solar power, then this technology can achieve zero carbon emissions. Although water electrolysis technology was discovered in the 19th century, its commercial application and large-scale production still face many technical and cost challenges.

[0003] Alkaline water electrolysis (ALK) uses an alkaline electrolyte (potassium hydroxide KOH or sodium hydroxide NaOH) to improve the efficiency of the electrolysis process. Compared to acidic or solid polymer electrolyte water electrolysis, ALK technology has the advantages of using cheaper catalysts, greater durability, and the ability to produce higher purity gases.

[0004] Photovoltaic water electrolysis, which directly couples solar cells and an electrolytic cell, is a green energy technology that converts and stores solar energy into chemical energy. Its advantages include high-efficiency energy conversion, reduced system complexity and cost, sustainability and environmental friendliness, and increased energy independence. In a photovoltaic water electrolysis device, solar cells absorb solar radiation to generate current, which drives the electrolytic cell to electrolyze water. However, the performance of solar cells is significantly affected by temperature; generally, for every 1°C increase in temperature, their output voltage decreases by 0.4%, and rising operating temperatures also reduce power generation efficiency and lifespan. The absorption of solar radiation by the solar cells raises their temperature, leading to a decline in their performance. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a photovoltaic direct-coupled water electrolysis device and method. It achieves highly efficient solar-driven water electrolysis through a compact alkaline water electrolyzer with a concave-convex structure incorporating solar cells. During operation, the electrolyte in the electrolyzer effectively cools the solar cells, resulting in better performance for both the solar cells and the alkaline water electrolyzer, and ultimately improving the efficiency of hydrogen production through electrolysis.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a photovoltaic direct-coupled water electrolysis device, comprising a photovoltaic unit, a water electrolysis unit, and a liquid circulation auxiliary unit;

[0008] The photovoltaic unit includes a solar cell;

[0009] The water electrolysis unit includes an anode clamp, an anode channel, an anode electrode, a diaphragm, a cathode electrode, a cathode channel, and a cathode clamp; the anode channel, anode electrode, diaphragm, cathode electrode, and cathode channel are stacked sequentially and are all located between the anode clamp and the cathode clamp;

[0010] The anode flow channel and the cathode flow channel are each connected to a liquid circulation auxiliary unit;

[0011] The solar cell supplies power to the anode and cathode electrodes; the solar cell is attached tightly to the anode clamp.

[0012] As a further improvement of the present invention, the liquid circulation auxiliary unit includes a pump, a gas-liquid separator, and a liquid pipeline;

[0013] The anode and cathode channels have a channel outlet and a channel inlet, respectively, and the liquid pipeline connects the channel outlet, the gas-liquid separator, the pump, and the channel inlet.

[0014] As a further improvement of the present invention, a gasket is provided between the anode clamp and the cathode clamp, and all components are fixedly connected by bolts.

[0015] As a further improvement of the present invention, the anode flow channel and the cathode flow channel are flow channels with concave and convex structures. The concave and convex structure refers to the upward provision of a protrusion and the downward provision of a groove on the plane of the anode flow channel or the cathode flow channel, and the protrusion and groove are evenly arranged. The concave and convex structures of the anode flow channel and the cathode flow channel are opposite in direction and are both located on the side away from the diaphragm.

[0016] As a further improvement of the present invention, the anode electrode and the cathode electrode are selected as porous nickel mesh electrodes.

[0017] As a further improvement of the present invention, the electrolyte in the anode channel and the cathode channel is selected as an alkaline solution.

[0018] As a further improvement of the present invention, the diaphragm is a membrane material with a porosity of 0.1 to 1.

[0019] As a further improvement of the present invention, the solar cell is a perovskite solar cell.

[0020] As a further improvement of the present invention, the solar cell is a FAPbI3-based perovskite solar cell, specifically structured as Sprio-OMeTAD / FAPbI3 / SnO2 / FTO.

[0021] Secondly, the present invention provides a water electrolysis method using a photovoltaic direct-coupled water electrolysis device, comprising the following steps:

[0022] Solar cells absorb external solar radiation and convert it into electrical energy, which is then connected to the anode and cathode electrodes via wires to supply power for the water electrolysis reaction in the water electrolysis unit.

[0023] The solar cell absorbs external solar radiation and heats up. The heat enters the anode channel, cathode channel, and diaphragm through the anode clamp. The electrolyte flows in the anode channel, anode electrode, cathode channel, cathode electrode, and liquid circulation auxiliary unit. The solar cell cools down under the action of the electrolyte flow. The electrolyte absorbs the heat transferred from the solar cell and heats up.

[0024] As a further improvement of the present invention, the water electrolysis reaction includes the following steps:

[0025] The electrolyte flows within the anode and cathode channels, entering the anode and cathode electrodes. After the circuit is connected, the KOH electrolyte on the anode side, under the influence of the anolyte current, releases OH-. - Oxidation occurs to produce O2; on the cathode electrode side, H2O molecules undergo reduction under the influence of the cathode current to produce H2 and OH. - Through the diaphragm, the generated O2 and H2 desorb and enter the anode channel and cathode channel respectively, mixing with the electrolyte in the outlet channel, and are separated and collected by the liquid circulation auxiliary unit.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The photovoltaic direct-coupled water electrolysis device of this invention utilizes solar cells to absorb external solar radiation and convert it into electrical energy, which powers the anode and cathode electrodes for the water electrolysis reaction in the electrolysis unit. By tightly fitting the solar cells to the anode clamp, the device simultaneously reduces the temperature of the solar cells and increases the temperature of the electrolyte during operation, thereby improving the operating efficiency of both the solar cells and the electrolyzer. This achieves highly efficient solar-driven water electrolysis in an alkaline electrolyzer. Compared to traditional water electrolysis devices, this invention achieves highly efficient solar-driven water electrolysis. Through electrolyte cooling, it simultaneously reduces the temperature of the solar cells and increases the temperature of the electrolyte, thus improving the operating efficiency of both the solar cells and the electrolyzer. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The shapes and proportions of the components in the drawings are merely schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportions of the components of the present invention. In the accompanying drawings:

[0029] Figure 1This is a schematic diagram of a photovoltaic direct-coupled water electrolysis device according to the present invention;

[0030] Figure 2 This is an assembly diagram of the water electrolysis unit of the present invention;

[0031] Figure 3 In this specific embodiment, the temperature of the solar cell and the temperature of the alkaline electrolyzer vary with the electrolyte flow rate.

[0032] Figure 4 The working current of the alkaline water electrolyzer in the specific embodiment varies with the electrolyte flow rate.

[0033] In the diagram, 1. Solar cell, 2. Anode clamp, 3. Wire, 4. Anode flow channel, 5. Gasket, 6. Cathode electrode, 7. Diaphragm, 8. Cathode clamp, 9. Cathode flow channel, 10. Anode electrode, 11. Pump, 12. Gas-liquid separator, 13. Liquid pipeline. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The purpose of this invention is to provide a photovoltaic direct-coupled water electrolysis device, including a photovoltaic unit, a water electrolysis unit, and a liquid circulation auxiliary unit;

[0036] The photovoltaic unit includes a solar cell 1 and a wire 3;

[0037] The water electrolysis unit includes an anode clamp 2, an anode flow channel 4, an anode electrode 10, a diaphragm 7, a cathode flow channel 9, a cathode electrode 6, and a cathode clamp 8; the anode flow channel 4, the anode electrode 10, the diaphragm 7, the cathode electrode 6, and the cathode flow channel 9 are stacked in sequence and are all located between the anode clamp 2 and the cathode clamp 8.

[0038] The anode flow channel 4 and the cathode flow channel 9 are respectively connected to a liquid circulation auxiliary unit; specifically, the liquid circulation auxiliary unit includes a pump 11, a gas-liquid separator 12, and a liquid pipeline 13;

[0039] The anode electrode 10, cathode electrode 6 and solar cell 1 are connected by wire 3. Solar cell 1 supplies power to anode electrode 10 and cathode electrode 6. Solar cell 1 is in close contact with anode clamp 2.

[0040] For water electrolysis, increasing the electrolyte temperature is beneficial to the electrolysis reaction. Direct coupling of the solar cell and the electrolytic cell allows the electrolyte in the cell to effectively cool the solar cell, lowering its temperature and improving battery performance. Simultaneously, the increased electrolyte temperature promotes the water electrolysis reaction, enhancing the overall system efficiency.

[0041] The coupling principle is as follows: Solar cell 1 absorbs external solar radiation and converts it into electrical energy, which is then connected to anode electrode 10 and cathode electrode 6 via wire 3 to provide power for the water electrolysis reaction in the water electrolysis unit.

[0042] Solar cell 1 absorbs external solar radiation and heats up. The heat enters the anode flow channel 4, cathode flow channel 9, and diaphragm 7 through the anode clamp 2. The electrolyte flows in the anode flow channel 4, anode electrode 10, cathode flow channel 9, cathode electrode 6, and liquid circulation auxiliary unit. Solar cell 1 cools down under the action of electrolyte flow, thus improving its performance. At the same time, the electrolyte absorbs the heat transferred from solar cell 1, causing it to heat up and enhancing the alkaline water electrolysis reaction.

[0043] As an embodiment of this application, the anode flow channel and the cathode flow channel have outlets and inlets respectively connected to a liquid pipeline, and the liquid pipeline connects the flow channel outlet, the gas-liquid separator, the pump and the flow channel inlet.

[0044] The principle of water electrolysis is as follows:

[0045] The electrolyte flows within the anode channel 4 and the cathode channel 9, and enters the anode electrode 10 and the cathode electrode 6. After the circuit is connected, the 10KOH electrolyte on the anode side, under the action of the anodic current, OH... - Oxidation occurs to generate O2; on the cathode electrode side 6, H2O molecules undergo reduction under the influence of the cathode current to generate H2 and OH. - The generated O2 and H2, after desorption through the diaphragm 7, enter the anode channel 4 and cathode channel 9 respectively, and mix with the electrolyte in the outlet channel. They are then separated and collected by the liquid circulation auxiliary unit.

[0046] In an embodiment of this application, a gasket 5 is provided between the anode clamp 2 and the cathode clamp 8, and all components are fixedly connected by bolts.

[0047] In this embodiment, the anode channel 4 and the cathode channel 9 are channels with a concave-convex structure. The concave-convex structure refers to the upward-facing protrusions and downward-facing grooves on the plane of the anode channel 4 or the cathode channel 9, with the protrusions and grooves evenly arranged. The concave-convex structures of the anode channel 4 and the cathode channel 9 are in opposite directions and are both located on the side opposite to the diaphragm 7. This invention improves upon the traditional alkaline water electrolysis device by designing the anode and cathode channels as concave-convex channels, and by placing the anode and cathode electrodes in close contact with the diaphragm 7. Compared to traditional electrolyzers, the concave-convex channel design enhances the desorption process of hydrogen and oxygen bubbles at the anode and cathode electrodes, accelerates the mixing of gas bubbles and electrolyte, and significantly reduces the ohmic resistance of the electrolyzer.

[0048] In this embodiment of the application, the anode electrode 10 and the cathode electrode 6 are porous nickel mesh electrodes; the electrolyte in the anode channel 4 and the cathode channel 9 is an alkaline solution, such as KOH solution.

[0049] As an embodiment of this application, the membrane 7 is a membrane material with a porosity of 0.1 to 1, and the solar cell 1 is selected as a FAPbI3-based perovskite solar cell.

[0050] As an example, the solar cell 1 is tightly attached to the anode clamp 2. Specifically, a solar cell groove is left on the anode clamp to tightly attach the solar cell 1 to the anode clamp 2, so as to realize the direct coupling of the solar cell to the alkaline electrolyzer for water electrolysis.

[0051] The principle of this device is as follows: Solar cell 1 absorbs external solar radiation and converts it into electrical energy, which is then supplied to the anode electrode 10 and cathode electrode 6 via wire 3, allowing a reaction to occur in the alkaline water electrolysis device; the electrolyte flows within the anode channel 4 and cathode channel 9, and enters the anode electrode 10 and cathode electrode 6; after the circuit is connected, the KOH electrolyte on the anode electrode 10 reacts with the OH- under the action of the anolyte current. - Oxidation occurs to generate O2; on the cathode electrode side 6, H2O molecules undergo reduction under the influence of the cathode current to generate H2 and OH. - After passing through the diaphragm 7, the generated O2 and H2 desorb and enter the anode channel 4 and cathode channel 9 respectively to mix with the electrolyte. Under the action of the pump 11, they are transported from the channel outlet to the gas-liquid separator 12 via the liquid pipeline 13. O2 or H2 is separated and collected in the gas-liquid separator 12. The electrolyte returns to the anode channel 4 or cathode channel 9 through the channel inlet via the liquid pipeline 13 to realize electrolyte circulation and participate in the water electrolysis reaction.

[0052] The second objective of this invention is to provide a water electrolysis method using a photovoltaic direct-coupled water electrolysis device, comprising the following steps:

[0053] Solar cell 1 absorbs external solar radiation and converts it into electrical energy, which is then connected to anode electrode 10 and cathode electrode 6 via wire 3 to provide power for the water electrolysis reaction in the water electrolysis unit.

[0054] Solar cell 1 absorbs external solar radiation and heats up. The heat enters the anode flow channel 4, diaphragm 7, and cathode flow channel 9 through anode clamp 2. The electrolyte flows in the anode flow channel 4, anode electrode 10, cathode flow channel 9, cathode electrode 6, and liquid circulation auxiliary unit. Solar cell 1 cools down under the action of electrolyte flow, thus improving its performance. At the same time, the electrolyte absorbs the heat transferred from solar cell 1, causing it to heat up and enhancing the alkaline water electrolysis reaction.

[0055] The present invention will be further described below with reference to the accompanying drawings (1-4).

[0056] like Figure 1 As shown, the photovoltaic direct-coupled water electrolysis device includes: 1. solar cell, 2. anode clamp, 3. wire, 4. anode flow channel, 5. gasket, 6. cathode electrode, 7. diaphragm, 8. cathode clamp, 9. cathode flow channel, 10. anode electrode, 11. pump, 12. gas-liquid separator, 13. liquid pipeline.

[0057] The photovoltaic unit consists of solar cell 1 and wire 3, while the water electrolysis unit consists of anode clamp 2, anode flow channel 4, and anode electrode 10. The assembly diagram is shown below. Figure 2 As shown, pump 11 and liquid pipeline 13 form a liquid circulation auxiliary unit.

[0058] The solar cell is a FAPbI3-based perovskite cell, specifically structured as Sprio-OMeTAD / FAPbI3 / SnO2 / FTO. It has an area of ​​5×5cm, an open-circuit voltage (Voc) of 2.21V, a short-circuit current of 328.38mA, a fill factor of 74.02%, and an efficiency of 21.47%.

[0059] The anode clamp 2 and the cathode clamp 8 are made of aluminum alloy with a thickness of 10mm.

[0060] The electrolyte is a 32% KOH solution.

[0061] The anode electrode 4 and the cathode electrode 6 are porous nickel mesh electrodes with a thickness of 0.6 mm, a porosity of 0.75, and a permeability of 1 × 10⁻⁶. -10 m 2 .

[0062] The membrane 7 has a thickness of 0.8 mm and a porosity of 0.5.

[0063] The reaction zones of the anode electrode 4, cathode electrode 6, and diaphragm 7 in the electrolytic cell are circular with a radius of 2 cm.

[0064] The photovoltaic direct-coupled water electrolysis device was placed under AM1.5G sunlight irradiation conditions and the ambient temperature was 25℃. The flow rate of the electrolyte was controlled by pump 11.

[0065] The temperature of the solar cell and the temperature of the alkaline electrolyzer in this device change with the electrolyte flow rate as follows: Figure 3 The results show that under 1 times the light intensity, the average temperature of the solar cell reached a maximum of 49.39℃, and the average temperature of the alkaline electrolytic cell reached a maximum of 47.52℃. As the electrolyte flow rate increased, the temperature of the entire system gradually decreased and gradually approached the ambient temperature of 25℃ and remained stable.

[0066] The operating current coupled to the alkaline water electrolysis cell in this device varies with the electrolyte flow rate, as follows: Figure 4 As the electrolyte flow rate increases, the operating current gradually rises, reaching a maximum operating current of 311.1 mA at a flow rate of 2.4 mL / min. After reaching the maximum operating current, the operating current gradually decreases with further increases in electrolyte flow rate. This indicates that low flow rates can effectively improve the performance of the solar cell, thereby enhancing the overall efficiency of the device.

[0067] Comparative Example

[0068] Except that the solar cell 1 and the anode clamp 2 are not in close contact, the rest is the same as in the embodiment. At this time, both the solar cell 1 and the alkaline electrolytic cell are in an environment of 25°C, and there is no heat exchange between them. Under this condition, the operating temperature of the solar cell is 62.2°C, and the operating temperature of the alkaline electrolytic cell is 25°C. Coupled with their operating IU curves, the operating current of the alkaline electrolytic cell is found to be 284.73mA.

[0069] In the photovoltaic direct-coupled water electrolysis device of this invention, the flow rate of the electrolyte is controlled by pump 11 to cool the entire device, thereby affecting the working performance of the solar cell 1 and the electrolyzer. Compared with the case where there is no heat exchange between the solar cell and the electrolyzer, this invention achieves an increase of 26.37mA of operating current at a flow rate of 2.4mL / min.

[0070] In summary, due to the tight fit between solar cell 1 and anode clamp 2, heat exchange occurs between solar cell 1 and the electrolytic cell, resulting in a decrease in the temperature of solar cell 1 and an increase in the temperature of the electrolytic cell, thereby improving the efficiency of the entire device. Furthermore, by regulating the electrolyte flow through pump 11 of the liquid circulation auxiliary unit, the temperature changes of the device can be controlled, allowing for the exploration of the relationship between device temperature and operating current, determination of optimal operating conditions, and a significant improvement in the efficiency of direct photovoltaic coupling in alkaline water electrolysis.

[0071] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation schemes of the present invention, and these modifications or equivalent substitutions do not depart from the spirit and scope of the present invention, and are all within the protection scope of the claims of the present invention.

[0073] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A photovoltaic direct-coupled water electrolysis device, characterized in that, Includes photovoltaic units, water electrolysis units, and liquid circulation auxiliary units; The photovoltaic unit includes a solar cell (1). The water electrolysis unit includes an anode clamp (2), an anode channel (4), an anode electrode (10), a diaphragm (7), a cathode electrode (6), a cathode channel (9), and a cathode clamp (8); the anode channel (4), anode electrode (10), diaphragm (7), cathode electrode (6), and cathode channel (9) are stacked in sequence and are all located between the anode clamp (2) and the cathode clamp (8); The anode flow channel (4) and the cathode flow channel (9) are respectively connected to a liquid circulation auxiliary unit; The solar cell (1) supplies power to the anode electrode (10) and the cathode electrode (6); the solar cell (1) is attached to the anode clamp (2); the solar cell (1) cools down under the action of the electrolyte flow; the electrolyte absorbs the heat transferred from the solar cell (1) and heats up. The liquid circulation auxiliary unit includes a pump (11), a gas-liquid separator (12), and a liquid pipeline (13). The anode flow channel (4) and the cathode flow channel (9) have flow channel outlet and flow channel inlet respectively, and the liquid pipeline (13) connects the flow channel outlet, the gas-liquid separator (12), the pump (11) and the flow channel inlet; The anode flow channel (4) and cathode flow channel (9) are flow channels with concave and convex structures. The concave and convex structure refers to the upward setting of the convex body and the downward setting of the groove on the plane of the anode flow channel (4) or cathode flow channel (9). The convex body and the groove are evenly arranged. The concave and convex structures of the anode flow channel (4) and cathode flow channel (9) are opposite in direction and are both set on the side away from the diaphragm (7). The solar cell (1) is a perovskite solar cell with a specific structure of Sprio-OMeTAD / FAPbI3 / SnO2 / FTO.

2. The photovoltaic direct-coupled water electrolysis device according to claim 1, characterized in that, A gasket (5) is provided between the anode clamp (2) and the cathode clamp (8), and all components are fixedly connected by bolts.

3. The photovoltaic direct-coupled water electrolysis device according to claim 1, characterized in that, The anode electrode (10) and cathode electrode (6) are selected as porous nickel mesh electrodes.

4. The photovoltaic direct-coupled water electrolysis device according to claim 1, characterized in that, The electrolyte in the anode channel (4) and cathode channel (9) is an alkaline solution.

5. The photovoltaic direct-coupled water electrolysis device according to claim 1, characterized in that, The diaphragm (7) is a membrane material with a porosity of 0.1 to 1.

6. The water electrolysis method of a photovoltaic direct-coupled water electrolysis device as described in any one of claims 1 to 5, characterized in that, Includes the following steps: The solar cell (1) absorbs external solar radiation and converts it into electrical energy. It is connected to the anode electrode (10) and the cathode electrode (6) through the wire (3) to supply power for the electrolysis reaction of water in the water electrolysis unit. The solar cell (1) absorbs external solar radiation and heats up. The heat enters the anode flow channel (4), cathode flow channel (9), and diaphragm (7) through the anode clamp (2). The electrolyte flows in the anode flow channel (4), anode electrode (10), cathode flow channel (9), cathode electrode (6), and liquid circulation auxiliary unit. The solar cell (1) cools down under the action of electrolyte flow. The electrolyte absorbs the heat transferred from the solar cell (1) and heats up.

7. The water electrolysis method according to claim 6, characterized in that, The water electrolysis reaction includes the following steps: The electrolyte flows in the anode channel (4) and the cathode channel (9), and enters the anode electrode (10) and the cathode electrode (6); after the circuit is connected, the KOH electrolyte on the anode electrode side (10) is subjected to the action of the anodic current. - Oxidation reaction occurs to generate O2; on the cathode electrode (6) side, H2O molecules undergo reduction reaction under the action of cathode current to generate H2 and OH. - Through the diaphragm (7), the generated O2 and H2 desorb and enter the anode channel (4) and cathode channel (9) respectively, mix with the electrolyte and flow out of the channel, and are separated and collected by the liquid circulation auxiliary unit respectively.

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