A sandwich liquid supply device for alkaline water electrolysis and an electrolyzer

Abstract

The application discloses a kind of interlayer liquid supply device and electrolytic cell for alkaline water electrolysis.The interlayer liquid supply device includes frame, interlayer support strip and lower row liquid inlet hole, frame two sides respectively with porous diaphragm fit, form liquid supply interlayer;Interlayer support strip is a plurality of parallel arrangement, with the upper and lower edges of frame interface wave-shaped partition strip, liquid supply interlayer is separated into a plurality of longitudinal liquid supply channel;Lower row liquid inlet hole is opened in the lower frame of frame, upward and each longitudinal liquid supply channel interface.The interlayer liquid supply device is equipped with two square end plate and bipolar plate, constitute complete liquid inlet channel and hydrogen side and oxygen side gas-liquid outflow channel.The application is pumped into electrolyte in liquid supply interlayer, so that electrolyte evenly fills each longitudinal liquid supply channel, and penetrates to the surface of cathode and anode on both sides, realizes horizontal direction full interface uniform liquid supply.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, specifically to a jacketed liquid supply device and electrolyzer for alkaline water electrolysis. Background Technology

[0002] Hydrogen production via water electrolysis using renewable energy provides an effective way to convert intermittent solar energy into storable and transportable hydrogen fuel, and is one of the most promising zero-carbon hydrogen production methods currently available. This technology not only addresses the time mismatch between renewable energy generation and consumption, but also provides feasible solutions for long-term energy storage and cross-sectoral energy coupling.

[0003] However, the inherent randomness, intermittency, and volatility of renewable energy pose significant challenges to water electrolysis systems. Unlike traditional steady-state operation, renewable energy-driven electrolyzers must adapt to rapid power fluctuations, partial load conditions, and frequent start-stop cycles. These operational characteristics exacerbate several key bottlenecks in alkaline water electrolysis technology, with the bubble effect being the most critical limiting factor.

[0004] Currently, the circular pressure filter alkaline electrolyzers widely used in industry have significant technical defects. First, the accumulation of bubbles in the electrolysis chamber and uneven electrolyte supply to the electrode surface greatly reduce the actual reaction area of ​​the electrodes, increasing the ohmic resistance of the electrolyte. This, in turn, increases ion mass transfer resistance and electrode polarization overpotential, ultimately leading to increased cell voltage and energy consumption. Second, gas accumulation promotes the cross-permeation of hydrogen and oxygen through the diaphragm, not only reducing the purity of the produced gas but also posing a serious explosion safety risk.

[0005] These problems become more pronounced under renewable energy-driven conditions. Especially when operating at low power density, insufficient gas generation leads to prolonged gas residence time and exacerbates diffusion-driven gas cross-contamination, causing the "hydrogen in oxygen" concentration to reach the safe shutdown threshold. This results in frequent abnormal shutdowns of the system, which not only accelerates the performance degradation of the electrolyzer but also causes a large amount of usable photovoltaic energy to be abandoned and wasted, thus fundamentally limiting the operating power range and energy efficiency of photovoltaic hydrogen production systems.

[0006] Although existing research has addressed these issues through control strategies such as power smoothing and energy storage integration, as well as technical approaches such as advanced separation membranes, optimized electrolyte formulations, and improved electrode materials, these methods generally suffer from increased system complexity, higher costs, or limited effectiveness, making it difficult to meet the demands of large-scale industrial applications. Therefore, developing an electrolyzer structure capable of achieving uniform electrolyte supply, efficient bubble management, and effective suppression of hydrogen-oxygen cross-conversion under power fluctuation conditions is of great significance for promoting the industrial application of large-scale direct "electricity-to-hydrogen" technology from renewable energy sources. Summary of the Invention

[0007] The purpose of this invention is to address the technical problems of existing alkaline electrolyzers under renewable energy driving conditions, such as uneven liquid supply on the electrode surface, severe bubble accumulation, and hydrogen-oxygen cross-permeation. This invention provides a jacketed liquid supply device and electrolyzer for alkaline water electrolysis, which achieves uniform liquid supply on the electrode surface and effective hydrogen-oxygen isolation, reduces electrolysis energy consumption, ensures gas purity under low power conditions, and adapts to the hydrogen production needs of renewable energy with power fluctuations and intermittency.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a jacketed liquid supply device for alkaline water electrolysis, comprising:

[0010] The frame is a thin rectangular structure, with porous diaphragms attached to both sides to form a liquid supply jacket.

[0011] The interlayer support strip consists of multiple parallel, wavy dividing strips that connect with the upper and lower edges of the frame, dividing the liquid supply interlayer into multiple longitudinal liquid supply channels.

[0012] The lower liquid inlet is located on the lower frame and connects upwards to each longitudinal liquid supply channel.

[0013] Furthermore, the thickness of the frame does not exceed 5 mm; the interlayer support strip is the same thickness as or slightly thinner than the frame, with a width of 1-3 mm and a spacing of 10-20 mm. These structural parameters ensure both the physical support function of the interlayer support strip, maintaining uniform interlayer thickness and good electrical contact between the electrode sheet and the flow channel ribs, and prevent the interlayer support strip from significantly affecting the electromigration of ions between the anode and cathode. They also ensure that the electrolyte is evenly distributed in each longitudinal channel and penetrates horizontally into the electrolysis chamber, alleviating the accumulation of bubbles in the electrolysis chamber.

[0014] In a second aspect, the present invention provides an alkaline electrolytic cell, comprising:

[0015] The aforementioned jacketed liquid supply device for alkaline water electrolysis;

[0016] A porous diaphragm is placed on both sides of the interlayer liquid supply device, and a hydrogen evolution electrode and an oxygen evolution electrode are placed on the outer side of the porous diaphragm, respectively.

[0017] The end plate is located outside the hydrogen evolution electrode and the oxygen evolution electrode and maintains electrical contact with the electrodes;

[0018] The above components are assembled into a complete groove using sealing rings and fastening screws.

[0019] Furthermore, the end plate and bipolar plate are provided with fluid channels to form a hydrogen-side electrolysis chamber and an oxygen-side electrolysis chamber; the lower part of the end plate and bipolar plate is provided with a rectangular liquid supply port, which is connected to the lower liquid inlet hole of the interlayer liquid supply device; the upper part of the end plate and bipolar plate is provided with a hydrogen-side outlet and an oxygen-side outlet.

[0020] Thirdly, the present invention provides an industrial jacketed liquid supply device for alkaline water electrolysis, which has the same structure as the aforementioned jacketed liquid supply device for alkaline water electrolysis, but its area is scaled up according to the industrial scale of water electrolysis.

[0021] The beneficial effects of this invention include:

[0022] (1) Achieve uniform liquid supply and improve electrolysis efficiency: The electrolyte is supplied to the entire interface of the electrode surface in the horizontal direction through the sandwich structure. The distance from the electrolyte to the entire electrode surface is only the thickness of the membrane, which ensures uniform liquid supply to the entire electrode surface, increases the actual reaction area of ​​the electrode, reduces the ohmic resistance of the electrolyte and the electrode polarization overpotential, thereby reducing the cell voltage and hydrogen production energy consumption.

[0023] (2) Effective management of bubbles and reduction of gas accumulation: The electrolyte reaches the electrode directly, which promotes the timely removal of bubbles from the electrode surface, reduces the accumulation of bubbles in the electrolysis chamber, reduces the mass transfer resistance and ohmic heat caused by bubbles, and improves the uniformity of current density and temperature distribution.

[0024] (3) Suppress hydrogen-oxygen cross-penetration and improve safety: The intermediate jacket liquid supply method effectively blocks the cross-penetration of gases between the two electrolysis chambers, improves the purity of hydrogen and oxygen, and can still maintain a low "hydrogen in oxygen" concentration under low power density operation conditions, avoiding reaching the safety shutdown threshold and reducing abnormal system shutdown.

[0025] (4) Adapting to power fluctuations and improving system stability: The above technical features make the present invention particularly suitable for direct electrolysis of renewable energy to produce hydrogen under power fluctuations and intermittent conditions. It can operate stably under rapid power fluctuations, partial load conditions and frequent start-stop cycles, thereby improving the operating power range and energy efficiency of renewable energy hydrogen production systems. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the jacketed liquid supply device for alkaline water electrolysis in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the hydrogen-side end plate in Embodiment 2 of the present invention;

[0028] Figure 3 This is a schematic diagram of the oxygen-side end plate in Embodiment 2 of the present invention;

[0029] Figure 4 This is a disassembly diagram of the single-cell electrolyzer in Embodiment 2 of the present invention;

[0030] Figure 5 This is a schematic diagram of a multi-cell series-connected pressure filter electrolyzer in Embodiment 3 of the present invention;

[0031] Figure 6 This is a schematic diagram of the industrial-scale scaled-up interlayer liquid supply device of Embodiment 3 of the present invention;

[0032] Figure 7 In Example 2 of this invention, at 1000 ml min -1 The single-cell voltage test data at different current densities under different electrolyte flow rates are shown in the graphs, tested in 1.0 M KOH solution at room temperature or in 6.0 M KOH solution at 80℃.

[0033] Figure 8 In Example 2 of this invention, at 1000 ml min -1 The graph shows the test data of hydrogen and oxygen purity and Faraday efficiency at different current densities under different electrolyte flow rates, tested in 1.0 M KOH solution at room temperature;

[0034] Figure 9 In Example 2 of this invention, at 1000 ml min -1 The graph shows the test data of hydrogen and oxygen purity and Faraday efficiency at different current densities under different electrolyte flow rates, tested in 6.0 M KOH solution at 80℃.

[0035] In the diagram: 1. Frame, 2. Interlayer support strip, 3. Liquid inlet, 4. Longitudinal liquid supply channel, 5. Diaphragm, 6. Hydrogen side end plate, 7. Oxygen side end plate, 8. Hydrogen side electrolysis chamber, 9. Hydrogen side outlet, 10. Oxygen side electrolysis chamber, 11. Oxygen side outlet, 12. Liquid supply port, 13. Electrolyte inlet channel, 14. Electrode plate, 15. Flow channel rib, 16. Sealing line area, 17. Sealing gasket, 18. Fastening screw, 19. Bipolar plate, 20. Pagoda connector. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] like Figure 1 As shown, the jacketed liquid supply device for alkaline water electrolysis includes:

[0039] Frame 1: Frame 1 is a thin rectangular structure with a thickness of no more than 5 mm. It is attached to the porous diaphragm 5 on both sides to form a liquid supply jacket.

[0040] The interlayer support strip 2 consists of multiple parallel dividing strips that connect to the upper and lower edges of the frame 1, dividing the liquid supply interlayer into multiple longitudinal liquid supply channels 4. The interlayer support strip 2 is the same thickness as or slightly thinner than the frame 1, with a width of 1-3 mm and a rib spacing of 10-20 mm. This design ensures both the physical support function of the interlayer support strip 2, resulting in uniform interlayer thickness and good electrical contact between the electrode sheet and the flow channel ribs, and avoids the interlayer support strip 2 significantly affecting the ion electromigration between the anode and cathode.

[0041] Lower inlet hole 3: The lower inlet hole 3 is opened on the lower edge of the frame 1 and connects upward to each longitudinal liquid supply channel 4.

[0042] The jacketed electrolyte supply device is made of polyphenylene sulfide (PPS) plastic. By pumping electrolyte into the supply jacket, the electrolyte permeates evenly to the electrode surfaces on both sides through the longitudinal supply channel 4, achieving uniform electrolyte supply to the entire electrode surface.

[0043] Example 2

[0044] like Figure 2-4 As shown, an alkaline electrolytic cell includes the jacketed liquid supply device, porous diaphragm 5, hydrogen-side end plate 6, and oxygen-side end plate 7 as described in Example 1.

[0045] Porous diaphragms 5: Placed on both sides of the interlayer liquid supply device, they are attached to the interlayer liquid supply device to allow the electrolyte to permeate evenly to the electrode surface. The diaphragm 5 can be made of polytetrafluoroethylene porous membrane, polyphenylene sulfide cloth, or polysulfone zirconium oxide composite diaphragm.

[0046] End plate structure: such as Figure 2 and Figure 3 As shown, the hydrogen-side end plate 6 and the oxygen-side end plate 7 are made of 316L stainless steel. The hydrogen-side end plate 6 is provided with a hydrogen-side electrolysis chamber 8 and a hydrogen-side outlet 9 at the top; the oxygen-side end plate 7 is provided with an oxygen-side electrolysis chamber 10 and an oxygen-side outlet 11 at the top. The electrolysis chamber area of ​​the end plate is provided with flow channel ribs 15, and the surrounding edges are provided with sealing line areas 16.

[0047] A rectangular liquid inlet 12 is provided at the lower part of the end plate, which is connected to the electrolyte inlet channel 13 and then connects to the lower inlet hole 3 of the interlayer liquid supply device to form a complete liquid inlet channel. The electrolyte is pumped in through the electrolyte inlet channel 13, and is evenly distributed to the electrode surface through the longitudinal liquid supply channel 4 of the interlayer liquid supply device. Finally, the generated hydrogen and oxygen flow out from the hydrogen side outlet 9 and oxygen side outlet 11, respectively.

[0048] Electrode materials: The hydrogen evolution electrode can be made of noble metal Pt or its alloy, or elemental or compound transition metals such as Ni, Mo, W, Co, etc.; the oxygen evolution electrode can be made of metal oxides RuO2, IrO2, or Raney nickel electrode, or transition metal compounds such as Ni, Co, etc.

[0049] The end plate, electrodes, porous diaphragm, and electrolyte supply jacket are assembled into a complete tank by insulating sealing gaskets 17 and fastening screws 18. Under appropriate pressure, the components are in close contact, ensuring that the electrolyte does not leak out of the tank.

[0050] Performance test results:

[0051] The assembled alkaline electrolyzer was subjected to performance testing. The hydrogen evolution electrode was a nickel-platinum electrode, the oxygen evolution electrode was a Raney nickel electrode, the diaphragm 5 was a polysulfone composite diaphragm, and the electrolyte flow rate was 1000 ml min⁻¹.

[0052] (1) Cell voltage test: Cell voltages at different current densities were tested under the conditions of 1.0 M KOH solution at room temperature and 6.0 M KOH solution at 80℃. Figure 7 As shown, at 80℃ and 6.0 M KOH (close to industrial conditions), with a current density of 400 mA cm⁻², the cell voltage is only 2.07 V, which is lower than the traditional industrial level.

[0053] (2) Gas purity test: Under room temperature and 1.0 M KOH conditions, with a current density range of 10-400 mA cm⁻², the purity of hydrogen and oxygen was analyzed using a gas chromatograph. For example... Figure 8 As shown, even at an extremely low current density of 10 mA cm⁻², the oxygen purity is still above 98.8%, and the "hydrogen in oxygen" concentration is below the industrial safety shutdown threshold (typically 2%).

[0054] (3) Faraday efficiency test: Under the same conditions, the gas production rate is measured using a soap film flow meter. For example... Figure 8 As shown, the Faraday efficiency remains above 99% when the current density is not less than 50 mA cm⁻²; even at an extremely low current density of 10 mA cm⁻², the Faraday efficiency still reaches 97.8%.

[0055] (4) High temperature and high concentration test: Under 80℃ and 6.0 M KOH conditions, such as Figure 9 As shown, the hydrogen purity remains above 99.3% across the entire current density range. Even at extremely low current densities of 10 mA cm⁻², the oxygen purity remains above 99.1%, the "hydrogen in oxygen" concentration is below the safe shutdown threshold, and the Faraday efficiency remains above 99.6% at current densities not lower than 50 mA cm⁻².

[0056] Example 3

[0057] like Figure 5 and Figure 6 As shown, this embodiment demonstrates an industrial scale-up application.

[0058] Multi-cell series electrolyzer: such as Figure 5 As shown, an industrial electrolyzer with a pressure filter structure, consisting of 2 end plates and 9 bipolar plates 19, comprising 10 electrolysis chambers, is designed to produce hydrogen at a rate of 2 Nm³ / h.

[0059] Industrialized jacketed liquid supply devices: such as Figure 6 As shown, the industrially scaled-up sandwich liquid supply device is surrounded by a frame 1, with internal sandwich support strips 2 to ensure uniform sandwich thickness and good electrical contact between the electrode plates and the flow channel ribs. The overall structure and thickness of the sandwich liquid supply device remain unchanged; in this example, the area is scaled up to 0.35m × 0.45m.

[0060] Industrial testing: at a current density of 400 mA cm⁻ 2 Electrolysis tests were conducted under industrial conditions at 80°C to verify the feasibility and stability of the invention under industrial scale-up conditions.

[0061] Overall Results: This invention, through the design of a jacketed liquid supply device, achieves uniform liquid supply to the electrode surface, effectively preventing hydrogen-oxygen cross-mixing, significantly reducing electrolysis energy consumption, and maintaining stable gas purity and Faraday efficiency over a wide power range. It is particularly suitable for renewable energy water electrolysis hydrogen production applications with power fluctuations, enabling stable operation under rapid power fluctuations and partial load conditions. This avoids frequent abnormal shutdowns caused by the "hydrogen in oxygen" concentration reaching the safety shutdown threshold, thus improving the operating power range and energy efficiency of renewable energy hydrogen production systems.

[0062] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A jacketed liquid supply device for alkaline water electrolysis, characterized in that, include: A frame, wherein two sides of the frame are respectively bonded to a porous diaphragm to form a liquid supply jacket; The interlayer support strip has multiple parallel wavy dividing strips that connect with the upper and lower edges of the frame, and the interlayer support strip divides the liquid supply interlayer into multiple longitudinal liquid supply channels. The lower liquid inlet is located on the lower frame and connects upwards to each longitudinal liquid supply channel.

2. The jacketed liquid supply device for alkaline water electrolysis according to claim 1, characterized in that: The thickness of the frame does not exceed 5 mm; the width of the interlayer support strips is 1-3 mm, and the interval is 10-20 mm.

3. An alkaline electrolytic cell, characterized in that, include: The jacketed liquid supply device for alkaline water electrolysis as described in any one of claims 1-2; A porous membrane is placed on both sides of the interlayer liquid supply device, and a hydrogen evolution electrode and an oxygen evolution electrode are placed on the outer side of the porous membrane. An end plate is located outside the hydrogen evolution electrode and the oxygen evolution electrode and maintains electrical contact with the electrodes. The above components are assembled into a complete groove using sealing rings and fastening screws.

4. An alkaline electrolytic cell according to claim 3, characterized in that: Fluid channels are provided on both the end plate and the bipolar plate, forming a hydrogen-side electrolysis chamber and an oxygen-side electrolysis chamber; a liquid supply port is provided at the lower part of the end plate and the bipolar plate, which is connected to the lower liquid inlet hole of the interlayer liquid supply device; a hydrogen-side outlet and an oxygen-side outlet are provided at the upper part of the end plate and the bipolar plate.

5. A jacketed liquid supply device for industrial alkaline water electrolysis, characterized in that: Its structure is the same as that of the jacketed liquid supply device for alkaline water electrolysis described in claim 1, and its area is scaled up according to the scale of industrial water electrolysis.

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