Electrode power supply control method for electrolysis process, system, and storage medium

Abstract

The present invention relates to the technical field of electrolysis processes, and in particular to an electrode power supply control method for an electrolysis process, a system, and a storage medium. The method of the present invention comprises: applying a first pulse voltage between an anode and a cathode, so that the voltage between the two electrodes increases rapidly; detecting a voltage rise waveform and / or a current in real time; and when condition 1 and / or condition 2 is met, stopping applying the first pulse voltage, and applying a second pulse voltage between a first electrode and a second electrode, wherein the polarity of the second pulse voltage is opposite to that of the first pulse voltage; condition 1 is that the slope of the voltage rise waveform decreases and then recovers; and condition 2 is that the magnitude of a stable current value increases, and then the current returns to the state before the increase; and during an electrolysis process, repeating these steps. The present invention can improve the efficiency of electrolysis processes and ensure the stability and service life of electrode catalysts. Therefore, the present invention has good application prospects.

Description

An electrode power supply control method, system, and storage medium for electrolysis processes. Technical Field

[0001] This invention belongs to the field of electrolysis technology, specifically relating to an electrode power supply control method, system, and storage medium for electrolysis processes. Background Technology

[0002] Electrolysis is a process that uses an electric current to pass through an electrolyte solution or molten material, causing oxidation and reduction reactions between the anode and cathode to separate, purify, or prepare substances. It is widely used in metal refining, electroplating, water electrolysis for hydrogen production, and the chlor-alkali industry.

[0003] The core of water electrolysis for hydrogen / oxygen production lies in improving energy conversion efficiency and reducing production costs. The development of catalytic electrodes primarily focuses on improving catalytic efficiency, reducing costs, and enhancing stability. Currently, porous nickel electrodes and high-performance nickel-based alloy electrodes are mainly used in water electrolysis for hydrogen / oxygen production. To improve catalytic efficiency, researchers are developing more efficient water electrolysis catalysts, especially bifunctional catalysts. These catalysts can simultaneously catalyze hydrogen evolution and oxygen evolution reactions, thereby simplifying the electrolysis system and reducing costs. For example, a research team at Yunnan University developed a catalyst coupled with an Ir single atom to a NiFe LDH / NiMo heterostructure. This catalyst exhibits high catalytic activity in alkaline electrolytes and remains stable during long-term operation.

[0004] These existing catalytic electrodes still suffer from several problems, such as high cost, poor stability, and performance degradation at high current densities. Catalysts are prone to detachment or deactivation at high current densities, leading to decreased catalytic performance. Specific causes of catalyst deactivation include particle agglomeration, phase transition, site poisoning, site dissolution, catalyst layer / particle detachment, and bubble blockage. These factors result in a reduction or passivation of active sites, thereby decreasing electrolysis efficiency.

[0005] Current research on solutions to reduced catalytic electrode activity mainly focuses on improving the catalyst itself. For example, Academician Sun Licheng's team developed a catalyst that can operate stably for over 19,100 hours at high current densities using a new process; the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, in collaboration with RIKEN in Japan, prepared a manganese dioxide electrolysis catalyst with ultralong-lasting stability. However, these studies are still some distance from commercial application.

[0006] On the other hand, improving the electrolysis process, such as controlling the power applied to the electrodes, is also a feasible way to improve the stability of catalytic electrodes. However, research in this area is currently limited, and no studies have been found on controlling the power supply in the electrolysis process to improve electrode stability and extend electrode life.

[0007] Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides an electrode power supply control method, system, and storage medium for electrolysis processes.

[0009] An electrode power supply control method for an electrolysis process, comprising:

[0010] A first pulse voltage is applied between the anode and cathode, causing the voltage between the two electrodes to rise rapidly;

[0011] Real-time detection of voltage rise waveform and / or current;

[0012] When condition 1 and / or condition 2 are met, the first pulse voltage is stopped, and a second pulse voltage is applied between the first electrode and the second electrode; the polarity of the second pulse voltage is opposite to that of the first pulse voltage.

[0013] Condition 1 is: the slope of the voltage rise waveform decreases, and then the slope recovers;

[0014] Condition 2 is: the stable current value increases, and then the current returns to the state before the increase;

[0015] The above steps are repeated during the electrolysis process.

[0016] Preferably, the first pulse voltage increases at a rate of 3V / μs or higher.

[0017] Preferably, the magnitude of the second pulse voltage does not exceed the electrode potential of the electrochemical reaction in the electrolysis process.

[0018] Preferably, the electrolysis process is a water electrolysis process, and the value of the second pulse voltage does not exceed 1.27V.

[0019] Preferably, the duration of the second pulse voltage is less than or equal to 100 μs.

[0020] Preferably, the reference 0V of the first pulse voltage is set on the cathode.

[0021] Preferably, the reference 0V of the second pulse voltage is set on the cathode.

[0022] The present invention also provides a system for implementing the above-described electrode power supply control method for electrolysis processes, comprising:

[0023] A pulse signal power supply is used to apply voltage to the anode and cathode;

[0024] The power control module is used to control the output of the pulse signal power supply according to the electrode power supply control method for the electrolysis process described above.

[0025] The present invention also provides an electrolytic cell device, which integrates the above-mentioned system.

[0026] The present invention also provides a computer-readable storage medium having stored thereon a computer program for implementing the above-described electrode power supply control method.

[0027] This invention proposes for the first time a method for controlling electrode power supply in an electrolysis process using pulsed voltage waveforms or current variations. Using this method, it is possible to remove coatings (e.g., oxidation products on the anode surface in water electrolysis) from the electrode surface in real time at precise points during the electrolysis process, thereby consistently maintaining the reactivity of the catalyst on the electrode surface. This invention facilitates efficient electrolysis, reduces energy consumption, and improves the stability and lifespan of the electrode catalyst; therefore, it has excellent application prospects.

[0028] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0029] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0030] Figure 1 shows the effect of an electric field on hydroxyl (OH) groups. - A schematic diagram showing the migration towards the vicinity of the anode;

[0031] Figure 2 is a schematic diagram of the conversion process of hydroxyl groups on the anode surface;

[0032] Figure 3 is a schematic diagram of the potential change caused by the release of electrons by hydroxyl groups on the anode surface;

[0033] Figure 4 is a schematic diagram showing the step in the pulse voltage waveform caused by the release of electrons by hydroxyl groups on the anode surface;

[0034] Figure 5 is a schematic diagram of the experimental apparatus for the power control method of the present invention in Experimental Example 1;

[0035] Figure 6 is a flowchart of the MCU control of the experimental device for the power control method of the present invention in Experiment Example 1;

[0036] Figure 7 is a schematic diagram of the control experimental setup for the existing method in Experimental Example 1;

[0037] Figure 8 shows the test results of the average current and average voltage of the power supply control method of the present invention and the existing method in Experiment Example 1. Detailed Implementation

[0038] It should be noted that the algorithms for data acquisition, transmission, storage and processing steps not specifically described in the embodiments, as well as the hardware structures and circuit connections not specifically described, can all be implemented using content already disclosed in the prior art.

[0039] Example 1: Electrode power supply control method, system, and storage medium for electrolysis process

[0040] The system in this embodiment includes:

[0041] A pulse signal power supply is used to apply voltage to the anode and cathode;

[0042] The power control module is used to control the output of the pulse signal power supply in the electrolysis process.

[0043] The control method for pulse signal power supply includes the following steps:

[0044] A first pulse voltage is applied between the anode and cathode, causing the voltage between the two electrodes to rise rapidly;

[0045] Real-time detection of voltage rise waveform and / or current;

[0046] When condition 1 and / or condition 2 are met, the first pulse voltage is stopped, and a second pulse voltage is applied between the first electrode and the second electrode; the polarity of the second pulse voltage is opposite to that of the first pulse voltage.

[0047] Condition 1 is: the slope of the voltage rise waveform decreases, and then the slope recovers;

[0048] Condition 2 is: the stable current value increases, and then the current returns to the state before the increase;

[0049] The above steps are repeated during the electrolysis process.

[0050] In a preferred embodiment, the first pulse voltage increases at a rate greater than or equal to 3V / μs. The magnitude of the second pulse voltage does not exceed the electrode potential of the electrochemical reaction in the electrolysis process. For example, in a water electrolysis process, the magnitude of the second pulse voltage does not exceed 1.27V. The duration of the second pulse voltage is less than or equal to 100μs. A reference voltage of 0V is set on the cathode for both the first and second pulse voltages.

[0051] The following uses the water electrolysis process as an example to explain the principle of controlling the pulse signal power supply output in this embodiment:

[0052] The device for electrolyzing water includes two electrodes: an anode, which is connected to the positive output of the electrolysis power supply; and a cathode, which is connected to the negative output of the electrolysis power supply. The two electrodes are not in contact and are simultaneously placed in an electrolyte solution with water as the solute.

[0053] When a voltage is applied between the two electrodes of the electrolysis device, the hydroxyl groups (OH-) produced by the dissociation (hydrolysis) of water under the influence of the electric field... - They migrate toward the vicinity of the anode (as shown in Figure 1).

[0054] Near the anode surface, the hydroxyl group, whose constituent oxygen atoms have more electrons and hydrogen atoms have fewer electrons, will move towards the electrode interface under the influence of the anodic electric field, while the hydrogen atom (which is now a proton) will move away.

[0055] During the approach process, when the hydrogen and oxygen electron cloud (formed by the movement of one electron) that holds the hydroxyl group comes into contact with the conductive material of the anode, the electron is captured by the anode, the hydroxyl group loses its bond and disintegrates, releasing oxygen, while the proton moves away from the anode and tends towards the cathode (as shown in Figure 2).

[0056] The release of electrons by hydroxyl groups on the anode surface is an instantaneous process, which affects the voltage of the anode conductor near the contact point, forming a momentary low-potential pulse during which electron exchange occurs. The potential change graph is shown in Figure 3.

[0057] When the electrode is connected to the pulse signal power supply, under the condition that the electrolyte has good conductivity, a clear step can be observed at the leading edge of the pulse (as shown in Figure 4).

[0058] This step is the voltage drop caused by electron exchange. This phenomenon can be detected when all hydroxyl groups on the anode surface undergo uniform electron exchange at the pulse leading edge, but it is difficult to detect during normal constant voltage or constant current electrolysis because hydroxyl groups in the liquid continuously release electrons.

[0059] When the hydroxyl group releases electrons, the oxygen atom approaches the surface of the anode electrode. At the moment of release, it can be considered that an electron cloud is shared between the oxygen atom and the electrode material (considered as a kind of chemical bond), causing the newly formed oxygen element to adhere to and cover the electrode surface. Although the electrode is a conductive material and the shared electrons will disappear inside the electrode, the instantaneous electron sharing already creates a fairly strong adsorption force between the oxygen element and the electrode material.

[0060] The newly formed oxygen layer covers the electrode surface, severely inhibiting the subsequent contact between hydroxyl groups and the electrode surface, as well as the opportunity for electron release. In terms of electrolytic cell performance, this necessitates a higher electrode driving voltage.

[0061] Furthermore, under constant voltage or constant current electrolysis, hydroxyl groups release electrons successively and completely at different points on the electrode. This means that different tiny high-frequency currents (electron flows) will appear at various points on the anode surface. The resulting electromagnetic induction will create eddy currents in the conductor of the anode, resulting in additional power consumption and heat generation. Therefore, significant anode heating can be observed during water electrolysis.

[0062] In existing technologies, the common approach to solving the above problems is to fabricate electrodes using molecularly or structurally modified materials (catalytic materials). One method involves modifying the material molecules to create multiple electric field singularities (electric field distortion) on their surface at nanometer or equivalent dimensions, resulting in partial discharge and the release of nascent oxygen. Another method involves altering the microstructure of the material surface through modification, thereby increasing the surface area and electron exchange area.

[0063] However, the electrolysis system is a strong redox system. In particular, even with an alkaline electrolyte, the anode region is still in a strongly acidic state, which greatly limits the choice of electrode materials. Those that meet the requirements of molecular or structural modification, especially porous or rough surfaces, cannot withstand tens or hundreds of thousands of hours of continuous operation.

[0064] In summary, in order to meet the actual requirements of water electrolysis for oxygen and hydrogen production, the service life must be given priority. To improve its Faraday efficiency, the working principle of the catalytic material is simulated, namely, electro-driven anode catalysis.

[0065] The principle of electrode surface change after adopting the power control method of this embodiment is as follows:

[0066] After the first pulse voltage is applied, the voltage rises at an extremely rapid rate. When the voltage rise waveform slows down (slope decreases) and the current increases, electron exchange occurs at the anode surface. The current returns to its pre-increase state, and the voltage rises at a similar rate (slope returns to normal). At this point, electrons have transferred from the hydroxyl groups to the electrode conductor, and the hydroxyl groups disintegrate to produce nascent oxygen molecules. However, these nascent oxygen molecules adhere to the electrode surface and exhibit negative charge. Immediately following, a second pulse voltage with reversed polarity is applied, switching the anode of the electrolytic cell to the negative terminal of the power supply. The negatively charged oxygen molecules repel the electrode and leave its surface. This prepares the conditions for the next application of the first pulse voltage.

[0067] The value of the second pulse voltage does not exceed the electrode potential of the electrolysis system. In a water electrolysis system, it does not exceed 1.27V. This setting aims to ensure that the flipping second pulse voltage does not cause gas evolution at the anode and cathode electrodes, thus ensuring the purity of the gas produced by the electrolyzer. The time does not exceed 100μs. This setting aims to allow only elemental oxygen molecules to detach from the electrode surface; the shorter the time, the higher the time utilization rate.

[0068] It should be noted that this embodiment uses the water electrolysis process as an example to illustrate the principle, but the technical solution of this embodiment is not only applicable to the water electrolysis process. Any other process in which electrode adsorption occurs during electrolysis, leading to a decrease in activity, can use the method of this embodiment for electrode power supply control.

[0069] Example 2 Electrolytic Cell Equipment

[0070] The present invention also provides an electrolytic cell device, which includes an electrolytic cell body, a cathode, and an anode, wherein the cathode and anode are supplied with voltage via a pulse signal power supply. This electrolytic cell device integrates the system described in Embodiment 1.

[0071] The technical effects of the present invention will be further illustrated by the following experiments.

[0072] Experimental Example 1: Comparison of the power control method of the present invention with existing methods

[0073] I. Experimental Methods

[0074] 1. Experimental apparatus for the power control method of the present invention

[0075] The experimental system is shown in Figure 5. Specifically:

[0076] Use a bidirectional DC power supply, adjusting the positive output to DC+6V (based on the neutral terminal 0V) and the negative output to DC-1.0V (based on the neutral terminal 0V). Connect the cathode in the electrolytic cell to the 0V (reference potential) power supply terminal, and connect the anode of the electrolytic cell to the output terminal of the catalytic power supply (pulse power supply).

[0077] The anode and cathode of the electrolytic cell are made of the same conductive material. This experiment uses a sintered metal oxide material (metal oxide ceramic), the main requirement of which is to prevent electro-corrosion during the experiment.

[0078] The anode of the electrolyzer is connected to the output of the catalytic power supply (pulse power supply). The catalytic power supply is a reverse pulse power signal source composed of a push-pull circuit consisting of two Darlington transistors, and the Darlington transistors are controlled by a B3 transistor (S9018) switch.

[0079] One characteristic of water electrolysis is that the voltage is not high, but the current is enormous. Its power supply typically uses a low-voltage, high-current type, with thyristors commonly used in industry as rectifier control elements. While thyristors are good switching devices, their characteristic is that they cannot be actively turned off, making it difficult to complete the required pulse switching process. Transistors are usually easier electronic switching devices for controlling on and off, but high-power (high-current) transistor catalytic power supplies have low amplification factors (hFE), making them difficult to drive with microcontroller output signals. Therefore, to achieve small-signal driving, two transistors are combined to form a Darlington transistor, thus achieving reliable drive control.

[0080] In the catalytic converter, the main power devices for Darlington transistors B1 and B2 are a pair of D44VH10G and D45VH10G transistors. These two transistors can dissipate 83W of power and draw 15A of current, but their hFE = 20, which is too small amplification factor, resulting in insufficient fan-out of the circuit. Therefore, a small power transistor is connected to their base to form a Darlington transistor circuit structure, increasing the overall amplification factor to 3000 to meet the control output capability of the MCU.

[0081] The microcontroller used is the Microchip PIC16F877A, which includes A / D conversion and storage functions. A 4MHz crystal oscillator was used in the experiment, providing a 1μs control and sampling interval, with a maximum output of 20mA. The MCU output was then isolated by a D1 Schmitt trigger CD40106 to obtain a steeper rise and fall edge control signal.

[0082] The anode of the electrolytic cell is also connected to a current sensor and a voltage sensor. The current sensor is a high-speed current signal acquisition sensor using a Risym AH3503 linear Hall element as its operating device, and its sensing cutoff frequency can reach 400kHz, meeting the requirements for detecting the electrolysis process. The voltage sensor detects the voltage value applied across the anode (between the anode and cathode) relative to a 0V reference and its changes.

[0083] The MCU is the control core of the catalytic power supply. At the start of the electrolysis process, the MCU outputs a high level, which, after being inverted by the Schmitt trigger (D1), sends a low level to transistor B3. The collector and emitter of B3 are disconnected. At this time, the +6V power supply is applied to the bases of B1 and B2 through resistor R1, causing the collector and emitter of B1 to conduct and the collector and emitter of B2 to disconnect. Ultimately, the display circuit outputs a high level, indicating a voltage rise between the anodes of the electrolytic cell (i.e., the first pulse voltage is applied). During the process, the current and voltage sensors continuously monitor their changes and send signals to the MCU. The MCU performs A / D conversion and calculation. When it detects a step in the voltage waveform and a sudden increase in current followed by recovery, it outputs a low level. After the Schmitt trigger (D1) inverts, it sends a high level to transistor B3, connecting the collector and emitter of B3. At this time, the -1V power supply is directly applied to the bases of B1 and B2, causing the collector and emitter of B1 to disconnect and the collector and emitter of B2 to conduct. Ultimately, the circuit outputs a negative level (i.e., the second pulse voltage is applied). The current and voltage sensors then send the subsequent signals to the MCU. When the voltage waveform and current waveform are detected to have recovered, the reverse voltage loading stops, and the MCU restarts high-level output (i.e., loading the first pulse voltage). The MCU control flowchart is shown in Figure 6.

[0084] Other methods or apparatus not specifically described are implemented according to the description in Example 1.

[0085] 2. Control experimental setup for existing methods

[0086] Test of average current-to-voltage ratio: Since the catalytic power supply outputs a power pulse signal, this experiment aims to compare the efficiency under constant current operating conditions using a control experimental setup. Therefore, it is necessary to measure the average current and voltage acting on the electrodes of the electrolyzer. The measurement circuit is designed as shown in Figure 7.

[0087] The measurement circuit is divided into average current measurement and average voltage measurement.

[0088] Average current measurement: A resistor R4 (100mΩ) is connected in series between the catalytic power source and the anode. When the electrolysis current flows through, a voltage drop is generated. This voltage drop is divided by R3 and R5 (500Ω), and a capacitor C1 (470μF) across R3 rectifies and filters the voltage to form a stable voltage. Measuring this stable voltage value is proportional to the current flowing through R4. The average current at this point is: I R4 =2V C1 ×R4

[0089] Among them, V C1 C1 is the rectified and filtered voltage, and R4 is the resistance value of resistor R4.

[0090] Average voltage measurement: A voltage divider is used with resistors R6 and R7. The voltage drop across R7 is filtered by capacitor C2 to form a regulated voltage. Measuring this regulated voltage value is proportional to the voltage across the anode. The average voltage is then calculated.

[0091] Among them, V C2 The voltage is regulated by the rectifier C2 after filtering. R6 is the resistance value of resistor R6, and R7 is the resistance value of resistor R7.

[0092] The reason why filter capacitors C1 and C2 are connected in the voltage divider circuit is to avoid affecting the change in the voltage waveform on the anode.

[0093] II. Experimental Results

[0094] In the experimental apparatus corresponding to the power control method of this invention, the anode and cathode of the electrolytic cell are driven by pulsating voltages, not the usual constant DC voltage drive. The purpose of this invention is to improve the efficiency of the electrolytic cell, that is, to lower the electrolytic voltage as much as possible under the same current. In other words, lower power is desirable. To evaluate the electrolytic efficiency, this experiment introduces the concept of "average current-to-voltage ratio". This means the ratio of the electrolytic current of the electrolytic cell to the average voltage between the anode and cathode. The higher this value, the higher the efficiency of the electrolytic cell. This is because, under the same voltage, the larger the current, the more electrons are exchanged on the electrodes, resulting in more hydrogen and oxygen produced, while the losses are smaller.

[0095] The experimental results of the two experimental setups are shown in Figure 8 and the table below:

[0096] The experimental results above show that, when using the electrode power supply control method of the present invention, the electrode voltage decreases under the same electrolysis current, indicating that the average current-to-voltage ratio of the method of the present invention is higher. Therefore, the method of the present invention has higher electrolysis efficiency and can reduce the energy consumption of electrolysis compared with the existing electrolysis voltage control methods.

[0097] As can be seen from the above embodiments, the present invention provides a method for controlling the electrode power supply in an electrolysis process by utilizing pulse voltage waveforms or current changes. This method can improve the efficiency of the electrolysis process, reduce electrolysis energy consumption, and ensure the stability and service life of the electrode catalyst. Therefore, the present invention has good application prospects.

Claims

1. A method for controlling electrode power supply in an electrolysis process, characterized in that, include: A first pulse voltage is applied between the anode and cathode, causing the voltage between the two electrodes to rise rapidly; Real-time detection of voltage rise waveform and / or current; When condition 1 and / or condition 2 are met, the first pulse voltage is stopped, and a second pulse voltage is applied between the first electrode and the second electrode. The second pulse voltage has the opposite polarity to the first pulse voltage; Condition 1 is: the slope of the voltage rise waveform decreases, and then the slope recovers; Condition 2 is: the stable current value increases, and then the current returns to the state before the increase; The above steps are repeated during the electrolysis process.

2. The electrode power supply control method for electrolysis process according to claim 1, characterized in that: The first pulse voltage increases at a rate of 3V / μs or greater.

3. The electrode power supply control method for electrolysis process according to claim 1, characterized in that: The magnitude of the second pulse voltage does not exceed the electrode potential of the electrochemical reaction in the electrolysis process.

4. The electrode power supply control method for electrolysis process according to claim 3, characterized in that: The electrolysis process is a water electrolysis process, and the value of the second pulse voltage does not exceed 1.27V.

5. The electrode power supply control method for electrolysis process according to claim 1, characterized in that: The duration of the second pulse voltage is less than or equal to 100 μs.

6. The electrode power supply control method for electrolysis process according to claim 1, characterized in that: The reference voltage 0V for the first pulse voltage is set on the cathode.

7. The electrode power supply control method for electrolysis process according to claim 1, characterized in that: The reference voltage 0V for the second pulse voltage is set on the cathode.

8. A system for implementing the electrode power supply control method for an electrolysis process according to any one of claims 1-7, characterized in that, include: A pulse signal power supply is used to apply voltage to the anode and cathode; A power control module is used to control the output of the pulse signal power supply according to the electrode power supply control method for electrolysis process according to any one of claims 1-7.

9. An electrolytic cell device, characterized in that: The electrolytic cell equipment integrates the system described in claim 8.

10. A computer-readable storage medium, characterized in that, It stores a computer program for implementing the electrode power supply control method for the electrolysis process as described in any one of claims 1-7.

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