Efficient alkali liquor electrolyzed water bipolar plate for realizing in-situ gas-liquid separation

Abstract

The invention discloses an efficient alkali liquor electrolyzed water bipolar plate for realizing on-site gas-liquid separation, which is characterized in that a hydrogen-liquid separation cavity and an oxygen-liquid separation cavity are independently arranged in the upper area of the bipolar plate, so that a pressure filtration type multi-chamber serial alkali liquor electrolytic bath assembled by the bipolar plate forms an expansion type gas-liquid separation area in the upper area; a liquid outlet channel and a gas outlet channel which are mutually independent are formed, so that on-site gas-liquid separation and smooth circulation of separated gas are realized; the bipolar plate comprises a main polar plate and an electrolysis chamber with two concave sides, one side of the bipolar plate is a hydrogen side, the other side of the bipolar plate is an oxygen side, and a hydrogen-liquid separation cavity is communicated with a hydrogen side outlet; and the oxygen-liquid separation cavity is communicated with the oxygen side outlet. According to the device, a gas-liquid mixture in the electrolysis chamber can be rapidly led out and rapidly separated on site, so that deposition of bubbles in the electrolysis chamber is effectively relieved, cross-membrane mixing of gas is avoided, the gas purity is improved, and the device is particularly suitable for direct electrolysis hydrogen production of renewable energy sources with power fluctuation.

Description

Technical Field

[0001] The invention relates to the technical field of water electrolysis hydrogen production equipment, in particular to an alkaline solution water electrolysis bipolar plate. Background Art

[0002] In the global energy strategic action plan, promoting the development of renewable energy and optimizing the energy structure have become one of the priorities of all countries. Producing green hydrogen by electrolysis of water through power provided by renewable energy such as solar energy, wind energy, and hydropower is an important way to achieve sustainable substitution of fossil fuels. However, renewable energy has the characteristics of randomness, intermittency, and volatility. Off-grid direct electrolysis of hydrogen production will inevitably aggravate the cross-mixing problem of hydrogen and oxygen on both sides of the diaphragm. Gas crossover not only reduces the purity of the gas production, but also may bring the risk of explosion. When the hydrogen content in oxygen reaches 2%, in order to avoid the occurrence of safety accidents, the electrolysis system will automatically shut down, which significantly reduces the conversion and utilization rate of renewable energy. Therefore, how to break through the technical bottleneck of cross-mixing of hydrogen and oxygen gases during electrolysis, ensure the high purity of hydrogen and oxygen under power fluctuation conditions, and avoid frequent shutdowns of the electrolysis system, has become the key to achieving large-scale direct "electric-to-hydrogen" of renewable energy.

[0003] At present, the circular filter-press alkaline electrolyzers commonly used in industry have local overheating and uneven gas-liquid distribution, which increases the ohmic resistance of the electrolyte and the electrode polarization overpotential, thereby increasing the cell pressure of the electrolyzer and increasing energy consumption. In response to these problems, the patent document with publication number CN117867551A discloses "an alkaline electrolyzer bipolar plate with uniform flow field effect", which reduces the concentration difference of the electrolyte in the flow channel by enhancing the disturbance of the flow; the patent document with publication number CN118581483A discloses "an alkaline water electrolysis bipolar plate and its preparation method and application", which has a specific three-dimensional structure flow channel, and reduces the flow resistance and pressure drop by improving the mass transfer of the gas-liquid mixture. However, the design of these technical solutions cannot solve the problems caused by the randomness, intermittency and volatility of renewable energy. The problem of gas cross-membrane mixing is not considered in the implementation strategy and implementation effect, and the purity of hydrogen and oxygen under wide power fluctuation conditions cannot be guaranteed. Summary of the invention

[0004] The present invention is to avoid the deficiencies of the above-mentioned prior art and provide a high-efficiency alkaline solution water electrolysis bipolar plate for realizing on-site gas-liquid separation. By accelerating the gas out of the electrolysis chamber and realizing on-site separation, the retention of hydrogen and oxygen and the mixing of the membrane are effectively reduced, and the purity and Faraday efficiency of the gas under low-power conditions are guaranteed. It is suitable for renewable energy sources such as photovoltaic and wind power with power fluctuations and intermittent properties, and promotes large-scale "electricity-to-hydrogen" of renewable energy. It is suitable for the industrially common filter press electrolytic cell structure with multiple electrolysis chambers connected in series and its associated pipeline operation system.

[0005] The present invention adopts the following technical solutions to solve the technical problems:

[0006] The high-efficiency alkaline liquid electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is characterized in that: two gas-liquid separation chambers are independently arranged in the upper area of ​​the bipolar plate, namely, a hydrogen-liquid separation chamber and an oxygen-liquid separation chamber, so that a filter-pressing type multi-chamber series-connected alkaline liquid electrolyzer assembled by the bipolar plate forms an expanded gas-liquid separation zone in the upper area, and forms mutually independent liquid outlet channels and gas outlet channels, so as to realize on-site gas-liquid separation and smooth flow of separated gas; the bipolar plate is a bipolar plate including a main pole plate and electrolysis chambers with concave shapes on both sides, one side of the bipolar plate is a hydrogen side, and a hydrogen side outlet is provided at the top of the hydrogen side electrolysis chamber; the other side of the bipolar plate is an oxygen side, and an oxygen side outlet is provided at the top of the oxygen side electrolysis chamber; the hydrogen-liquid separation chamber is connected with the hydrogen side outlet; the oxygen-liquid separation chamber is connected with the oxygen side outlet.

[0007] The high-efficiency alkaline liquid electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is also characterized in that: the bipolar plate is a rectangular plate, and the hydrogen-liquid separation chamber and the oxygen-liquid separation chamber are two rectangular cavities arranged in parallel in the upper area of ​​the bipolar plate; the two rectangular cavities are connected to the hydrogen side outlet and the oxygen side outlet in a one-to-one correspondence with their respective bottom edge openings.

[0008] The high-efficiency alkaline solution water electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is also characterized in that: the width L of the electrolysis chamber is set to: L = L1 + L2 + L3;

[0009] Where: L1 is the width of the hydrogen side outlet; L2 is the width of the oxygen side outlet;

[0010] L3 is the width of the interval area between the hydrogen side outlet and the oxygen side outlet;

[0011] And: L3 = 2-6 cm; the width of the hydrogen side outlet is twice the width of the oxygen side outlet, so that the cross-sectional area of ​​the hydrogen-liquid separation chamber is twice the cross-sectional area of ​​the oxygen-liquid separation chamber.

[0012] The high-efficiency alkaline liquid electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is also characterized in that: in the electrolysis chamber, main ribs and secondary ribs are separated to form multiple electrolyte flow channels; liquid supply channels and liquid supply inlets are provided at the bottom of the bipolar plate, namely: hydrogen side liquid supply channel and hydrogen side liquid supply inlet, and oxygen side liquid supply channel and oxygen side liquid supply inlet; liquid outlet channels and gas outlet channels are provided at the lower edge and upper edge of the separation chamber, respectively: the hydrogen liquid outlet channel is located at the lower edge of the hydrogen-liquid separation chamber, and the hydrogen gas outlet channel is located at the upper edge of the hydrogen-liquid separation chamber; the oxygen liquid outlet channel is located at the lower edge of the oxygen-liquid separation chamber, and the oxygen gas outlet channel is located at the upper edge of the oxygen-liquid separation chamber; so that gas and liquid are discharged from the electrolytic cell through independent channels.

[0013] The high-efficiency alkaline liquid water electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is also characterized in that: the hollow height of the hydrogen-liquid separation chamber and the oxygen-liquid separation chamber is 1 / 5-1 / 2 of the width of the electrolysis chamber; the height of the liquid supply channel and the liquid outlet channel is set to 2-5mm to meet the heat dissipation requirements of the electrolyte circulation; the liquid supply channel and the corresponding separation chamber are located at diagonal positions and are connected by electrolyte flow channels evenly distributed on the corresponding side of the bipolar plate.

[0014] The high-efficiency alkaline solution water electrolysis bipolar plate for realizing on-site gas-liquid separation of the present invention is also characterized in that: a defoaming screen is fixed in the middle of the hydrogen-liquid separation chamber and the oxygen-liquid separation chamber to remove mist in the gas; the defoaming screen is a metal screen, a polytetrafluoroethylene screen, or a polypropylene screen.

[0015] The retention of gas in the electrolysis chamber leads to the cross-mixing of hydrogen and oxygen on both sides of the diaphragm, which not only reduces the purity of gas production, but also may bring explosion risks; renewable energy is characterized by randomness, intermittency and volatility. Directly driving electrolysis to produce hydrogen will inevitably lead to large fluctuations in the internal pressure of the electrolyzer and frequent starts and stops. In low-power electrolysis, the rate of gas cross-mixing may even exceed the rate of hydrogen and oxygen generation, further exacerbating the mutual penetration of gases and reducing the Faraday efficiency of the electrolysis process. Therefore, how to break through the technical bottleneck of cross-mixing of hydrogen and oxygen gases during electrolysis has become the key to achieving large-scale direct "electricity to hydrogen" from renewable energy. Compared with the existing technology, the beneficial effects of the present invention are reflected in:

[0016] 1. The present invention provides a gas-liquid separation chamber on the upper part of the bipolar plate to quickly guide out the gas-liquid mixture in the electrolysis chamber and achieve rapid separation. The gas is quickly discharged through an independent gas outlet channel, which effectively reduces the accumulation of bubbles in the electrolysis chamber and avoids cross-membrane mixing of gases, thereby significantly improving the purity of gas production and Faraday efficiency.

[0017] 2. The present invention realizes the rapid extraction and on-site separation of gas-liquid mixture, effectively adapting to the intermittent and volatile characteristics of renewable energy; effectively avoiding the instability caused by gas retention and cross-membrane mixing, greatly broadening the normal operating electrolysis power range, reducing the start-up and shutdown frequency of the electrolyzer, and is suitable for large-scale "electricity-to-hydrogen" application scenarios.

[0018] 3. The present invention obviously reduces the risk of local pressure increase and overheating caused by gas retention, reduces the ohmic resistance and polarization overpotential of the electrolyte, and reduces the resistance of gas retention to the flow of the electrolyte, thereby reducing the electrolytic cell pressure and improving the electrolysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the hydrogen side of the bipolar plate in the present invention;

[0020] Figure 2 Schematic diagram of the oxygen side of the bipolar plate in the present invention;

[0021] Figure 3 A three-dimensional schematic diagram of an electrolytic cell according to an embodiment of the present invention;

[0022] Figure 4 A cross-sectional view of the hydrogen-side gas-liquid outlet portion of an embodiment of the present invention;

[0023] Figure 5 A cross-sectional view of the gas-liquid outlet portion on the oxygen side of an embodiment of the present invention;

[0024] Figure 6 The purity and Faraday efficiency test data of hydrogen and oxygen at different current densities in the present invention are tested in 2.0M KOH solution at room temperature.

[0025] Figure 7 The purity and Faraday efficiency test data of hydrogen and oxygen at different current densities in the present invention are tested in 80°C 6.0M KOH solution.

[0026] Numbers in the figure: 1 pole frame, 2 sealing line area, 3 main pole plate, 4 electrolysis chamber, 5 main rib, 6 secondary rib, 7 electrolyte flow channel, 8 hydrogen side liquid supply channel, 9 hydrogen side liquid supply inlet, 10 hydrogen side outlet, 11 hydrogen-liquid separation chamber, 12 hydrogen-liquid outlet channel, 13 hydrogen gas outlet channel, 14 oxygen side liquid supply channel, 15 oxygen side liquid supply inlet, 16 oxygen side outlet, 17 oxygen-liquid separation chamber, 18 oxygen-liquid outlet channel, 19 oxygen gas outlet channel, 20 bipolar plate, 21 end plate, 22 insulating sealing gasket, 23 gas-liquid transfer tank, 24 gas outlet, 25 fastening screw, 26 power terminal, 27 defoaming wire mesh. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the embodiments. It should be noted that these are merely examples and illustrations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should be deemed to fall within the protection scope of the present invention.

[0028] See also Figure 1 and Figure 2 In this embodiment, the high-efficiency alkaline liquid electrolysis water bipolar plate for realizing gas-liquid in-situ separation is to independently set two gas-liquid separation chambers in the upper area of ​​the bipolar plate, namely the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17, so that the filter-pressing type multi-chamber series alkaline liquid electrolyzer assembled by the bipolar plate forms an expanded gas-liquid separation zone in the upper area, and forms independent liquid outlet channels and gas outlet channels, so as to realize gas-liquid in-situ separation and smooth flow of separated gas;

[0029] The bipolar plate is a bipolar plate including a main electrode plate 3 and an electrolysis chamber 4 with concave shapes on both sides. One side of the bipolar plate is a hydrogen side, and a hydrogen side outlet 10 is provided at the top of the hydrogen side electrolysis chamber; the other side of the bipolar plate is an oxygen side, and an oxygen side outlet 16 is provided at the top of the oxygen side electrolysis chamber; the hydrogen-liquid separation chamber 11 is connected to the hydrogen side outlet 10; and the oxygen-liquid separation chamber 17 is connected to the oxygen side outlet 16.

[0030] In this embodiment, the bipolar plate is a rectangular plate, and the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17 are two rectangular cavities arranged side by side in the upper area of ​​the bipolar plate; the two rectangular cavities are connected to the hydrogen side outlet 10 and the oxygen side outlet 16 in a one-to-one correspondence with their respective bottom edge openings.

[0031] The corresponding technical measures in this embodiment also include:

[0032] The width L of the electrolysis chamber 4 is set to: L = L1 + L2 + L3;

[0033] Wherein: L1 is the width of the hydrogen side outlet 10; L2 is the width of the oxygen side outlet 16;

[0034] L3 is the width of the interval area between the hydrogen side outlet 10 and the oxygen side outlet 16;

[0035] And: L3 = 2-6cm; the width of the hydrogen side outlet 10 is twice the width of the oxygen side outlet 16, so that the cross-sectional area of ​​the hydrogen-liquid separation chamber is twice the cross-sectional area of ​​the oxygen-liquid separation chamber.

[0036] Figure 1 and Figure 2 As shown, in the electrolysis chamber 4, main ribs 5 and secondary ribs 6 are separated to form multiple electrolyte flow channels 7; liquid supply channels and liquid supply inlets are provided at the bottom of the bipolar plate, namely: hydrogen side liquid supply channel 8 and hydrogen side liquid supply inlet 9, and oxygen side liquid supply channel 14 and oxygen side liquid supply inlet 15; liquid outlet channels and gas outlet channels are provided at the lower edge and upper edge of the separation chamber, respectively: hydrogen liquid outlet channel 12 is located at the lower edge of the hydrogen-liquid separation chamber 11, and hydrogen gas outlet channel 13 is located at the upper edge of the hydrogen-liquid separation chamber 11; oxygen liquid outlet channel 18 is located at the lower edge of the oxygen-liquid separation chamber 17, and oxygen gas outlet channel 19 is located at the upper edge of the oxygen-liquid separation chamber 17; so that gas and liquid are discharged from the electrolytic cell through independent channels.

[0037] In this embodiment, the hollow height of the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17 is set to 1 / 5-1 / 2 of the width of the electrolysis chamber 4; the height of the liquid supply channel and the liquid outlet channel is set to 2-5mm to meet the heat dissipation requirements of the electrolyte circulation; the liquid supply channel and the corresponding separation chamber are located at diagonal positions and are connected by electrolyte flow channels evenly distributed on the corresponding side of the bipolar plate.

[0038] Figure 4and Figure 5 As shown, in this embodiment, a defoaming screen 27 is fixed in the middle of the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17 to remove mist in the gas. The defoaming screen 27 is a metal screen, a polytetrafluoroethylene screen, or a polypropylene screen. The separated gas and liquid pass through multiple discharge ports at the upper edge and the lower edge respectively, and continue to separate in each separation chamber along the way.

[0039] The corresponding technical measures in this embodiment also include:

[0040] Figure 1 and Figure 2 As shown, the rectangular bipolar plate is surrounded by a pole frame 1, the hydrogen-side liquid supply channel 8 and the oxygen-side liquid supply channel 14 are located at the lower part of the pole frame on the corresponding side, the outer edge of the pole frame 1 is set as a sealing line area 2, and the lower edges of the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17 are both provided with slit through holes, which serve as the hydrogen-liquid outlet channel 12 and the oxygen-liquid outlet channel 18 respectively; the upper edges of the hydrogen-liquid separation chamber 11 and the oxygen-liquid separation chamber 17 are also provided with slit through holes, which serve as the hydrogen outlet channel 13 and the oxygen outlet channel 19 respectively, and the hydrogen and oxygen that undergo gas-liquid separation in the gas-liquid separation chamber are separated from the liquid respectively, and are quickly discharged from the electrolyzer along the hydrogen outlet channel 13 and the oxygen outlet channel 19.

[0041] Figure 3 As shown, according to the predetermined scale of hydrogen production by electrolysis, bipolar plates of corresponding number and area are assembled into a filter press type electrolyzer consisting of multiple electrolysis chambers connected in series, the electrolyzer comprises several bipolar plates 20, and the structural parts at both ends also include: end plate 21, gas-liquid transfer tank 23, gas outlet 24, and power supply terminal 26; the components are assembled into an integrated structure of the filter press type electrolyzer by fastening screws 25, and a pair of cathode and anode are installed in the electrolysis chamber 4 surrounded by each two bipolar plates, and the two electrodes are separated by a diaphragm. The peripheral edges of the main plate 3 and the internal protruding main ribs 5 and secondary ribs 6, the electrode sheet and the diaphragm are in close contact under the pressure applied by the fastening screws 25, so as to minimize the resistance of electron conduction and ion migration. The circumferential pole frame 1 between every two bipolar plates is provided with an insulating sealing gasket 22 for reliable sealing, forming a sealing line area 2 to ensure that the electrolyte does not leak out of the tank body; the material of the bipolar plates, end plates, and tank body components of the gas-liquid transfer tank is 316L stainless steel.

[0042] The hydrogen side electrolysis chamber, the hydrogen-liquid separation chamber, the gas-liquid transfer tank at the hydrogen end, and the hydrogen side liquid supply channel constitute one of the electrolyte circuits; the oxygen side electrolysis chamber, the oxygen-liquid separation chamber, the oxygen end gas-liquid transfer tank, and the oxygen side liquid supply channel constitute the other electrolyte circuit; the electrolyte in the two electrolyte circuits surges upward by natural convection driven by the difference in bubble density in the electrolysis chamber. In the two gas-liquid separation chambers, hydrogen and oxygen are separated from the electrolyte, the liquid is discharged horizontally from the liquid outlet channel at the lower edge of the separation chamber, and the gas is discharged horizontally from the gas outlet channel at the upper edge of the separation chamber, and both flow to the gas-liquid transfer tank 23 outside the tank, and the gas is then discharged from the gas outlet 24 on the gas-liquid transfer tank. Hydrogen and oxygen enter the subsequent drying, impurity removal and pressurization links, and finally enter the hydrogen storage cylinder and the oxygen storage cylinder. The small amount of bubbles remaining in the electrolyte continue to escape from the electrolyte in the gas-liquid transfer tank. A water replenishment hole is provided on the cover of the gas-liquid transfer tank.

[0043] The hydrogen-producing electrode can be made of precious metal Pt or Pd, or a composite of precious metal Pt or Pd and carbon, or a single substance or compound of transition metal Ni, Mo, W, Co, Cu and Fe; the oxygen-producing electrode can be made of metal oxide Ru or Ir, or a composite of metal oxide Ru or Ir and carbon, or a Raney nickel electrode, or a transition metal compound of Ni, Co, Cu or Fe; the diaphragm can be made of polyphenylene sulfide PPS, anion exchange membrane, Zirfon, and various composite membranes.

[0044] In this embodiment, a PPS diaphragm with medium gas isolation performance, which is commonly used in the alkaline solution electrolysis water industry, is used to evaluate the effect of the bipolar plate of the present invention in improving gas purity.

[0045] Test 1: Under the operating conditions of room temperature and low alkali concentration, the controlled current mode was adopted to collect hydrogen and oxygen samples respectively, and the purity was analyzed by gas chromatograph. The relationship between the purity of hydrogen and oxygen (expressed as volume percentage) and the current density was obtained, as shown in Fig. Figure 6 This example was tested at room temperature, the alkali solution was 2.0M KOH, and the current density range was 10-400mAcm -2 , the anode and cathode are both made of ordinary nickel mesh electrodes, and the diaphragm is made of PPS. Three bipolar plates and two end plates are used to form four electrolysis chambers in series. The test results show that the purity of hydrogen remains above 99.9% in the entire current density range, which is almost independent of the current density. The purity of oxygen is slightly lower than that of hydrogen, and it decreases as the current density decreases, but even at 10mA cm -2 At extremely low current density, the oxygen purity is still above 99.5%, which is much higher than the industrial shutdown threshold of "hydrogen in oxygen".

[0046] Test 2: Under the operating conditions of room temperature and low alkali concentration, the volume of hydrogen and oxygen produced in a certain time interval was measured using a soap film flowmeter in the controlled current mode. The volume was compared with the theoretical gas production to obtain the relationship between the Faraday efficiency of electrolytic gas production and the current density, as shown in Figure 2. Figure 6 This example was tested at room temperature, the alkali solution was 2.0M KOH, and the current density range was 10-400 mA cm -2 The anode and cathode are both made of ordinary nickel mesh electrodes, and the diaphragm is made of PPS. Three bipolar plates and two end plates are used to form four electrolytic chambers in series. The test results show that when the current density is not less than 50mAcm -2 The Faradaic efficiency remains above 99% when the current density decreases, but it decreases slightly when the current density decreases, but even at 10 mA cm -2 Even at extremely low current density, the Faradaic efficiency still reaches a high level of 98%.

[0047] Test 3: Under industrial operating conditions of high temperature and high alkali concentration, the controlled current mode was used to collect hydrogen and oxygen samples respectively, and the purity was analyzed by gas chromatograph. The relationship between the purity of hydrogen and oxygen (expressed as volume percentage) and the current density was obtained, as shown in Figure 3. Figure 7 This example was tested at an alkali solution temperature of 80°C, the alkali solution was 6.0M KOH, and the current density range was 10-400 mA cm -2 , Raney nickel electrodes are used for both the anode and cathode, and PPS is used for the diaphragm. Three bipolar plates and two end plates are used to form four electrolysis chambers in series. The test results show that the purity of hydrogen remains above 99.8% in the entire current density range, and decreases slightly with the decrease of current density. The purity of oxygen is slightly lower than that of hydrogen, and decreases with the decrease of current density, but even at 10mA cm -2 At extremely low current density, the oxygen purity is still above 99%, which is higher than the industrial shutdown threshold of "hydrogen in oxygen".

[0048] Test 4: Under industrial operating conditions of high temperature and high alkali concentration, the volume of hydrogen and oxygen produced in a certain time interval was measured using a soap film flowmeter in the controlled current mode. The volume was compared with the theoretical gas production to obtain the relationship between the Faraday efficiency of electrolytic gas production and the current density, as shown in Figure 4. Figure 7 This example was tested at an alkali solution temperature of 80°C, the alkali solution was 6.0M KOH, and the current density range was 10-400 mA cm -2 The anode and cathode are both made of Raney nickel electrodes, and the diaphragm is made of PPS. Three bipolar plates and two end plates are used to form four electrolytic chambers in series. The test results show that when the current density is not less than 50mA cm -2The Faraday efficiency remains above 98.5% when the current density decreases, but it decreases slightly even at 10 mA cm -2 At extremely low current density, the Faradaic efficiency is still above 96.5%.

[0049] The present invention designs the gas-liquid separation chamber above the bipolar plate to have a gas-liquid separation function, which prompts the gas to quickly leave the electrolysis chamber, significantly reduces gas crossover, and improves the purity and Faraday efficiency of the output gas. Compared with the results measured under the same electrolysis conditions of the traditional circular small channel bipolar plate electrolyzer, the bipolar plate with gas-liquid separation function of the present invention has significant advantages in gas purity and Faraday efficiency, and can be applied to the electrolysis of water to produce hydrogen at very low current density, greatly broadening the power range for normal operation.

[0050] The above is an exemplary description of the invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A high-efficiency alkaline solution electrolysis bipolar plate for realizing on-site gas-liquid separation, characterized in that: Two gas-liquid separation chambers are independently arranged in the upper region of the bipolar plate, namely, a hydrogen-liquid separation chamber (11) and an oxygen-liquid separation chamber (17), so that a filter-press type multi-chamber alkali liquid electrolyzer assembled by the bipolar plate forms an expanded gas-liquid separation zone in the upper region, and forms mutually independent liquid outlet channels and gas outlet channels, so as to realize on-site gas-liquid separation and smooth flow of separated gas; the bipolar plate is a bipolar plate comprising a main pole plate (3) and electrolysis chambers (4) with concave shapes on both sides, one side of the bipolar plate is a hydrogen side, and a hydrogen side outlet (10) is provided at the top of the hydrogen side electrolysis chamber; the other side of the bipolar plate is an oxygen side, and an oxygen side outlet (16) is provided at the top of the oxygen side electrolysis chamber; the hydrogen-liquid separation chamber (11) is connected to the hydrogen side outlet (10); and the oxygen-liquid separation chamber (17) is connected to the oxygen side outlet (16).

2. The high-efficiency alkaline solution electrolysis bipolar plate for realizing in-situ gas-liquid separation according to claim 1 is characterized in that: The bipolar plate is a rectangular plate, and the hydrogen-liquid separation chamber (11) and the oxygen-liquid separation chamber (17) are two rectangular cavities arranged side by side in the upper region of the bipolar plate; the two rectangular cavities are connected to the hydrogen side outlet (10) and the oxygen side outlet (16) in a one-to-one correspondence with their respective bottom edge openings.

3. The high-efficiency alkaline solution electrolysis bipolar plate for realizing in-situ gas-liquid separation according to claim 2 is characterized in that: The width L of the electrolysis chamber (4) is set to: L = L1 + L2 + L3; Wherein: L1 is the width of the hydrogen side outlet (10); L2 is the width of the oxygen side outlet (16); L3 is the width of the interval area between the hydrogen side outlet (10) and the oxygen side outlet (16); And: L3 = 2-6 cm; the width of the hydrogen side outlet (10) is twice the width of the oxygen side outlet (16), so that the cross-sectional area of ​​the hydrogen-liquid separation chamber is twice the cross-sectional area of ​​the oxygen-liquid separation chamber.

4. The high-efficiency alkaline solution electrolysis bipolar plate for realizing on-site gas-liquid separation according to claim 1 or 2, characterized in that: In the electrolysis chamber (4), main ribs (5) and secondary ribs (6) are separated to form a plurality of electrolyte flow channels (7); liquid supply channels and liquid supply inlets are provided at the bottom of the bipolar plate, namely: a hydrogen side liquid supply channel (8) and a hydrogen side liquid supply inlet (9), and an oxygen side liquid supply channel (14) and an oxygen side liquid supply inlet (15); liquid outlet channels and gas outlet channels are provided at the lower edge and upper edge of the separation chamber, respectively: a hydrogen liquid outlet channel (12) is located at the lower edge of the hydrogen-liquid separation chamber (11), and a hydrogen gas outlet channel (13) is located at the upper edge of the hydrogen-liquid separation chamber (11); an oxygen liquid outlet channel (18) is located at the lower edge of the oxygen-liquid separation chamber (17), and an oxygen gas outlet channel (19) is located at the upper edge of the oxygen-liquid separation chamber (17); gas and liquid are discharged from the electrolytic cell through independent channels.

5. The high-efficiency alkaline solution electrolysis bipolar plate for realizing in-situ gas-liquid separation according to claim 1 or 2, characterized in that: The hollow height of the hydrogen-liquid separation chamber (11) and the oxygen-liquid separation chamber (17) is 1 / 5 to 1 / 2 of the width of the electrolysis chamber (4). The height of the liquid supply channel and the liquid outlet channel is set to 2-5 mm to meet the heat dissipation requirements of the electrolyte circulation; The liquid supply channel and the corresponding separation chamber are located at diagonal positions and are connected by electrolyte flow channels evenly distributed on the corresponding side of the bipolar plate.

6. The high-efficiency alkaline solution electrolysis bipolar plate for realizing on-site gas-liquid separation according to claim 1 is characterized in that: A defoaming screen (27) is fixed in the middle of the hydrogen-liquid separation chamber (11) and the oxygen-liquid separation chamber (17) to remove mist in the gas; the defoaming screen (27) is a screen made of metal material, a screen made of polytetrafluoroethylene material, or a screen made of polypropylene material.

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