An in-situ power supply system for seawater dissolved oxygen batteries at full ocean depth

Abstract

The present invention provides an in-situ power supply system for a seawater dissolved oxygen battery at full ocean depth, comprising a plurality of seawater battery power generation units, a DC / DC boost unit, an energy storage battery unit, a load, a backup battery unit, a load power supply switch, a power management unit and a pressure-resistant cabin; through the technical scheme of the present invention, the in-situ power supply system for a seawater dissolved oxygen battery at full ocean depth has high positive electrode electrocatalytic activity, can work normally when the dissolved oxygen concentration in seawater is as low as 0.5 mg / L, has the ability to resist fouling by marine organisms, has high specific power density, has a small battery size, has high power generation efficiency and energy utilization rate, and also has the advantages of simple manufacturing, low production cost, and suitability for industrial production, and is suitable for long-term, stable and safe power supply in units of years at full ocean depth.

Description

Technical Field

[0001] The present invention relates to the field of chemical ocean energy for in-situ electricity generation using seawater, and in particular to an in-situ power supply system for seawater dissolved oxygen batteries used at full ocean depth. Background Art

[0002] Seawater dissolved oxygen battery is referred to as seawater battery (SWB), in which seawater is used as electrolyte and dissolved oxygen in seawater is used as cathode reaction active substance, oxygen reduction reaction (ORR) occurs on positive carbon fiber brush electrode, magnesium anode dissolution reaction occurs with high-activity magnesium alloy as negative electrode, and continuous supply of oxygen and elimination of byproducts on electrode surface (cathode product - calcium carbonate and anode product - magnesium hydroxide) are achieved under the action of ocean current, thus forming a primary battery. Since dissolved oxygen in seawater is inexhaustible and the large amount of magnesium ions contained in it can be refined and regenerated, it can be considered as an environmentally friendly and renewable chemical ocean energy.

[0003] At present, the power supply for long-term seabed observation adopts cables or batteries. The former requires laying cables on the seabed and power supply from shore-based power stations. The advantage is sufficient power supply, but the disadvantages are long distance, large investment, poor safety, difficult management and maintenance, and low flexibility. The latter requires high-energy density batteries for power supply. Currently, primary lithium batteries are mainly used. The advantage is high energy density, but the disadvantage is low output power. For the power supply demand of tens of watts and several years, multiple groups of series and parallel assembly are required. The number of uses is huge, and the safety problem is prominent. It needs to be placed in a specific pressure-resistant container. The actual volume and weight of the battery pack are large and expensive. Energy supply is still a common key technical problem that needs to be solved urgently for long-term continuous real-time observation of the seabed.

[0004] Seawater batteries have significant features (no need to carry electrolytes, energy density up to 700Wh Kg -1 , open structure, high safety) have shown great advantages in the marine field. However, the existing seawater batteries also have prominent disadvantages: low concentration of dissolved oxygen in seawater, poor activity of cathode materials; low working current density of the battery, poor specific power density; large cathode area required for high power output, resulting in a large battery volume. Therefore, the core issue of developing advanced seawater batteries is how to significantly increase the specific power density and achieve long-term, stable and safe power supply capabilities in years.

[0005] In summary, the development of an in-situ power supply system for seawater dissolved oxygen batteries for use at full ocean depth is still a key issue that needs to be urgently addressed in the field of chemical ocean energy that utilizes seawater to generate electricity in situ. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, the present invention provides an in-situ power supply system for seawater dissolved oxygen batteries for full ocean depth.

[0007] The present invention is realized by the following technical scheme: an in-situ power supply system of seawater dissolved oxygen battery for full sea depth, comprising a plurality of seawater battery power generation units, a DC / DC boost unit, an energy storage battery unit, a load, a backup battery unit, a load power supply switch, a power management unit and a pressure-resistant cabin,

[0008] The seawater battery power generation unit includes a magnesium alloy negative electrode and a positive electrode composed of a carbon fiber brush electrode surrounding the negative electrode;

[0009] Each of the seawater battery power generation units is equipped with an independent DC / DC boost unit, which boosts the low voltage output by each of the seawater battery power generation units to a DC / DC boost unit that meets the load requirements, and after boosting the power generated by each seawater battery power generation unit, the power is stored in the energy storage battery unit through multiple parallel seawater battery power generation units and DC / DC boost units;

[0010] The energy storage battery unit adopts the charging and discharging mode, and supplies power to the load through the load power supply switch;

[0011] Backup battery unit When the energy storage battery unit cannot supply power to the load, the backup battery supplies power to the load through the load power switch;

[0012] The power management unit is used for system monitoring and control, data acquisition and storage, and real-time data communication;

[0013] The DC / DC boost unit, energy storage battery unit, backup battery unit, load power supply switch and power management unit are placed together in the pressure cabin. The seawater battery power generation unit and load outside the pressure cabin are connected to the inside of the pressure cabin through a pressure-resistant watertight cable.

[0014] As a preferred solution, the open circuit potential of the magnesium alloy negative electrode is negative -1.7V, and the potential during operation is negative -1.4V, both of which are relative to a saturated calomel electrode; the utilization rate of the magnesium alloy negative electrode is not less than 50%, and the working life is not less than 1 year.

[0015] As a preferred solution, the output power of the seawater battery power generation unit is 1-10 W, and the volume power density is not less than 5W / m 3 .

[0016] As a preferred solution, the DC / DC boost unit boosts the DC low voltage 1.0-2.0V to a DC high voltage 5-36V, and the boost energy conversion efficiency is not less than 70%.

[0017] As a preferred solution, the energy storage battery unit is a secondary battery, and its cyclic charge and discharge capability is a capacity retention rate of more than 85% after 1,500 cycles, and its design capacity is more than 1.5 times the daily power generation of a multi-channel parallel seawater battery power generation unit + a DC / DC boost unit; the backup battery unit is a primary battery or a secondary battery, and its design capacity is more than twice the capacity of the energy storage battery unit, and its annual self-discharge rate is less than 10%.

[0018] As a preferred solution, the monitoring and control of the power management unit is carried out by collecting the output voltage and current of each seawater battery power generation unit to determine its power generation capacity and working status; by collecting the output voltage and current of the energy storage battery unit to determine its power supply capacity and working status. When it is judged that the capacity of the energy storage battery unit is less than 30%, the load power supply switch is used to switch to the backup battery unit to supply power to the load. When it is judged that the capacity of the energy storage battery unit is restored to 90%, the load power supply switch is used to switch back to the energy storage battery unit to supply power to the load.

[0019] As a preferred solution, the data acquisition and storage of the power management unit is to acquire and store the following: including the output voltage and current of each seawater battery power generation unit, the status data of the DC / DC boost unit (on is 1, off is 0), the output voltage and current at both ends of the load, and the status data of the energy storage battery unit and the backup battery unit (on is 1, off is 0).

[0020] As a preferred solution, the real-time data communication of the power management unit is to send the current or historical data of the seawater dissolved oxygen battery in-situ power supply system to the user via cable, hydroacoustic + network, or hydroacoustic + satellite communication.

[0021] As a preferred embodiment, the positive electrode constituted by the carbon fiber brush electrode is an oxygen reduction electrode of an electrochemically modified carbon fiber brush composite silver, and the carbon fiber brush electrode is made by weaving raw materials of polyacrylonitrile-based carbon fiber tow and titanium wire; the carbon fiber brush electrode is placed in an electrolyte solution containing aniline, and after cyclic treatment between electrochemical oxidation and electrochemical reduction, an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface is prepared; the electrochemically modified carbon fiber brush electrode is placed in a silver nitrate solution, and silver is deposited through electrochemical reduction to obtain an oxygen reduction electrode of an electrochemically modified carbon fiber brush composite silver.

[0022] Due to the adoption of the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the in-situ power supply system of the seawater dissolved oxygen battery for full sea depth provided by the present invention has high positive electrode electrocatalytic activity, can work normally even when the dissolved oxygen concentration in seawater is as low as 0.5 mg / L, has the ability to resist marine biological fouling, has high specific power density, small battery volume, high power generation efficiency and energy utilization rate, and also has the advantages of simple manufacturing, low production cost, and suitability for industrial production, and is suitable for long-term, stable and safe power supply in units of years at full sea depth.

[0023] Additional aspects and advantages of the present invention will become apparent in the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of the structural composition of the in-situ power supply system of the seawater dissolved oxygen battery;

[0026] Figure 2 This is a schematic diagram of the structure of the seawater battery power generation unit in the seawater dissolved oxygen battery in-situ power supply system. DETAILED DESCRIPTION

[0027] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] The present invention proposes an in-situ power supply system for seawater dissolved oxygen batteries for full sea depth, characterized in that it comprises a plurality of seawater battery power generation units 3, a DC / DC boost unit 4, an energy storage battery unit 5, a load 6, a backup battery unit 7, a load power supply switch 8, a power management unit 9 and a pressure cabin 10, wherein the seawater battery power generation unit 3 comprises a magnesium alloy negative electrode 1 and a positive electrode 2 composed of a carbon fiber brush electrode surrounding the negative electrode; each seawater battery power generation unit 3 is configured with an independent DC / DC boost unit 4, which boosts the low voltage 1.0-2.0V output by each of the seawater battery power generation units 3 to a DC / DC boost unit 4 that meets the load requirement of 5-36V, and generates electricity from each seawater battery power generation unit 3 through After boosting, the electric energy is stored in the energy storage battery unit 5 through the multi-channel parallel seawater battery power generation unit 3 and the DC / DC boost unit 4; the energy storage battery unit 5 adopts the charge-and-discharge mode, and supplies power to the load 6 through the load power supply switch 8; when the energy storage battery unit 5 cannot supply power to the load, the backup battery 7 supplies power to the load through the load power supply switch 8; the power management unit 9 is used for monitoring and control of the power supply system, data acquisition and storage, and real-time data communication; the DC / DC boost unit 4, the energy storage battery unit 5, the backup battery unit 7, the load power supply switch 8 and the power management unit 9 are placed in a pressure cabin 10, and the seawater battery power generation unit 3 and the load 6 outside the pressure cabin 10 are connected to the inside of the pressure cabin 10 through a pressure-resistant watertight cable 1.

[0030] Preferably, the open circuit potential of the magnesium alloy negative electrode is negative -1.7V, and the potential during operation is negative -1.4V, both of which are relative to a saturated calomel electrode; the utilization rate of the magnesium alloy negative electrode is not less than 50%, and the working life is not less than 1 year.

[0031] Preferably, the output power of the seawater battery power generation unit 1 is 1-10 W, and the volume power density is not less than 5 W / m 3 .

[0032] Preferably, the DC / DC boost unit 4 boosts the DC low voltage 1.0-2.0V to a DC high voltage 5-36V, and the boosted energy conversion efficiency is not less than 70%.

[0033] Preferably, the energy storage battery unit 5 is a secondary battery, and its cyclic charge and discharge capability is a capacity retention rate of more than 85% after 1500 cycles, and its design capacity is more than 1.5 times the daily power generation of the multi-way parallel seawater battery power generation unit 1 + DC / DC boost unit 4; the backup battery unit 7 is a primary battery or a secondary battery, and its design capacity is more than twice the capacity of the energy storage battery unit 5, and its annual self-discharge rate is less than 10%.

[0034] Preferably, the monitoring and control of the power management unit 9 is performed by collecting the output voltage and current of each seawater battery power generation unit 3 to determine its power generation capacity and working status; by collecting the output voltage and current of the energy storage battery unit 5 to determine its power supply capacity and working status. When it is judged that the capacity of the energy storage battery unit 5 is lower than 30%, the power supply switch of the load 6 is used to switch to the backup battery unit 7 to supply power to the load 6. When it is judged that the capacity of the energy storage battery unit 5 is restored to 90%, the power supply switch of the load 6 is used to switch back to the energy storage battery unit 5 to supply power to the load 6.

[0035] Preferably, the data acquisition and storage of the power management unit 9 is to acquire and store the following contents: including the output voltage and current of each seawater battery power generation unit 1, the status data of the DC / DC boost unit 4 (on is 1, off is 0), the output voltage and current across the load 6, and the status data of the energy storage battery unit 5 and the backup battery unit (7) (on is 1, off is 0).

[0036] Preferably, the real-time data communication of the power management unit 9 is via cable, hydroacoustic + network, or hydroacoustic + satellite communication to send the current or historical data of the seawater dissolved oxygen battery in-situ power supply system to the user.

[0037] Preferably, the positive electrode formed by the carbon fiber brush electrode is an oxygen reduction electrode of an electrochemically modified carbon fiber brush composite silver, which is made of a raw material polyacrylonitrile-based carbon fiber tow and a titanium wire through weaving to form a carbon fiber brush electrode; the carbon fiber brush electrode is placed in an electrolyte solution containing aniline, and after a cyclic treatment between electrochemical oxidation and electrochemical reduction, an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface is prepared; the electrochemically modified carbon fiber brush electrode is placed in a silver nitrate solution, and silver is deposited by electrochemical reduction to obtain an electrochemically modified carbon fiber brush composite silver oxygen reduction electrode. Among them, the nitrogen-containing active functional group is obtained by the inherent nitrogen in the raw material polyacrylonitrile-based carbon fiber and the nitrogen from aniline in the solution, which is obtained by a cyclic treatment of electrochemical oxidation and electrochemical reduction in an electrolyte solution containing aniline; wherein, the composite metallic silver is obtained by further electrochemically reducing the silver ions in the silver nitrate solution and depositing them on the electrode. The nitrogen-containing active functional groups in the active layer cooperate with metallic silver to have high electrocatalytic activity for ORR, and can still work normally even if the dissolved oxygen concentration in seawater is as low as 0.5 mg / L. Metallic silver also has the ability to resist fouling by marine organisms. Therefore, the positive electrode composed of the above-mentioned carbon fiber brush electrode ensures that the seawater dissolved oxygen battery in-situ power supply system of the present invention has a long-term, stable and safe power supply capability in units of years at full sea depth.

[0038] The electrochemical oxidation and electrochemical reduction in the electrolyte solution containing aniline are different from the traditional electrochemical synthesis of polyaniline. The intensity of electrochemical oxidation and electrochemical reduction is higher, reaching the level of oxygen evolution reaction and hydrogen evolution reaction in water electrolysis, respectively, and polyaniline cannot stably exist on the electrode surface. That is, the purpose of the present invention is to use aniline as a nitrogen source. In the cyclic treatment process of the above-mentioned electrochemical oxidation and electrochemical reduction, an electrochemical reaction occurs between aniline and carbon fiber, thereby enriching the types and quantities of the above-mentioned nitrogen-containing active functional groups on the electrode surface, thereby improving the electrocatalytic activity for ORR. Composite metallic silver is prepared by placing the above-mentioned electrochemically modified carbon fiber brush electrode in an aqueous solution of silver nitrate, and through electrochemical reduction, metallic silver is deposited on the surface of the electrochemically modified carbon fiber brush to form a discontinuous silver layer composed of silver particles, and then an active layer composed of composite metallic silver with nitrogen-containing active functional groups is formed, and finally an oxygen reduction electrode of an electrochemically modified carbon fiber brush composite silver is obtained.

[0039] Combine the following Figure 1 to Figure 2 The in-situ power supply system of the seawater dissolved oxygen battery for full ocean depth according to the embodiment of the present invention is described in detail.

[0040] Example 1

[0041] This embodiment provides a single-channel seawater dissolved oxygen battery in-situ power supply system, which includes a seawater battery power generation unit. The structural schematic diagram of the seawater battery power generation unit is shown in FIG. Figure 2 As shown. A titanium frame with a square outside and a circular inside (0.5 m long × 0.5 m wide × 1 m high) is made of titanium alloy. A carbon fiber brush electrode is electrically connected to the inner circular titanium frame (0.5 m) by welding or bolts as the positive electrode. Its specifications are 3 cm × 90 cm long, and the number is 25. They are evenly spaced and evenly distributed on the inner circular titanium frame. It is also an oxygen reduction electrode of electrochemically modified carbon fiber brush composite silver; a magnesium alloy rod with a diameter of 25 cm × 90 cm long is fixed in the center of the titanium frame as the negative electrode, which is watertightly insulated from the titanium alloy frame. The open circuit potential of the magnesium alloy is -1.9V, and the working potential is -1.7V (relative to the saturated calomel electrode). The utilization rate of the magnesium alloy negative electrode is 50%. The rated output power of the above-mentioned seawater battery power generation unit is 4.5W, and it can continuously generate electricity in seawater for 1.5 years.

[0042] The seawater battery power generation unit is boosted from 1.2-1.9V to 12V through a DC / DC boost device, with a boost efficiency of 80%, that is, 3.6W of electricity is continuously stored in a 12V / 12Ah solid-state lithium-ion battery (energy storage battery), and the charging and discharging mode is used to continuously power a sensor load (rated power 3W) at a depth of 10,000 meters. At the same time, a set of 12V / 25Ah solid-state lithium-ion batteries is equipped as a backup battery to provide power when the energy storage battery is insufficient due to extreme environments such as severe sea conditions, and in emergency situations.

[0043] The single-channel seawater dissolved oxygen battery in-situ power supply system of this embodiment is also equipped with power management to realize power supply monitoring and control, data collection and storage, and real-time data communication. The power generation capacity and working status of the seawater battery are judged by collecting the output voltage and current of the power generated by the seawater battery; the power supply capacity and working status of the energy storage battery are judged by collecting the output voltage and current of the energy storage battery. When the capacity of the energy storage battery is less than 30%, the load power supply switch is used to switch to the backup battery to power the load. When the capacity of the energy storage battery is restored to 90%, the load power supply switch is used to switch back to the energy storage battery to power the load; the output voltage and current of the seawater battery, the status data of the boost device (open is 1, closed is 0), the output voltage and current at both ends of the load, and the status data of the energy storage battery and the backup battery (open is 1, closed is 0); through cable communication, the status data of the current seawater dissolved oxygen battery in-situ power supply system is transmitted according to the load requirements.

[0044] The above-mentioned boost devices, energy storage batteries, backup batteries and power management are placed together in a pressure-resistant cabin that can withstand water depths of 10,000 meters. The seawater battery power generation unit and load outside the cabin are connected to the cabin via a pressure-resistant watertight cable that can withstand water depths of 10,000 meters.

[0045] Example 2

[0046] This embodiment provides an 8-way seawater dissolved oxygen battery in-situ power supply system, which contains 8 seawater battery power generation units used in parallel. Each seawater battery power generation unit is made of a titanium alloy into a hollow cylindrical titanium frame (0.5 meters in diameter and 0.6 meters in height), and a carbon fiber brush electrode is electrically connected to the titanium frame by welding or bolts as a positive electrode, and its specifications are 7 cm in diameter and 45 cm in length, and the number is 16, which are evenly spaced and evenly distributed on the titanium frame. It is also an oxygen reduction electrode of electrochemically modified carbon fiber brush composite silver, that is, after the cyclic treatment of electrochemical oxidation and electrochemical reduction in an electrolyte solution containing aniline, the silver ions in the silver nitrate solution are further electrochemically reduced and deposited on the electrode; a magnesium alloy rod of 30 cm in diameter and 50 cm in length is fixed in the center of the titanium frame as a negative electrode, which is watertightly insulated from the titanium alloy frame, and the open circuit potential of the magnesium alloy is -2.0V, and the working potential is -1.9V (relative to the saturated calomel electrode), and the utilization rate of the magnesium alloy negative electrode is 60%. The rated output power of the above-mentioned single seawater battery power generation unit is 1.8W, and it can generate electricity continuously in seawater for 3 years.

[0047] Each of the above seawater battery power generation units is independently boosted from 1.2-1.9V to 24V through a DC / DC boost device, with a boost efficiency of 70%, that is, a total of 10 W of electricity from 8 channels is continuously stored in a 24V / 20Ah ternary lithium-ion battery (energy storage battery), and a 6000-meter deep-sea mining environment monitoring system (load) is intermittently powered in a charging and discharging mode. At the same time, a set of 24V / 60Ah ternary lithium-ion batteries is equipped as a backup battery, which provides power for the load in safety mode when the energy storage battery is insufficient due to extreme environments such as severe sea conditions, and in emergency situations.

[0048] The 8-way seawater dissolved oxygen battery in-situ power supply system of this embodiment is also equipped with power management to realize power supply monitoring and control, data collection and storage, and real-time data communication. The power generation capacity and working status of the seawater battery are judged by collecting the output voltage and current of the seawater battery; the power supply capacity and working status of the energy storage battery are judged by collecting the output voltage and current of the energy storage battery. When the capacity of the energy storage battery is less than 30%, the load power supply switch is used to switch to the backup battery to power the load. When the capacity of the energy storage battery is restored to 90%, the load power supply switch is used to switch back to the energy storage battery to power the load; the output voltage and current of the seawater battery, the status data of the boost device (open is 1, closed is 0), the output voltage and current at both ends of the load, and the status data of the energy storage battery and the backup battery (open is 1, closed is 0); through hydroacoustic + satellite communication, the operating data of the seawater dissolved oxygen battery in-situ power supply system in the current and a certain time period are transmitted according to the load requirements.

[0049] The above-mentioned boost devices, energy storage batteries, backup batteries and power management are placed together in a pressure-resistant cabin that can withstand a water depth of 6,000 meters. The seawater battery power generation unit and load outside the cabin are connected to the cabin through a pressure-resistant watertight cable that can withstand a water depth of 6,000 meters.

[0050] According to the design principles of the present invention and the above-mentioned implementation methods, users can determine the power generation capacity, power supply working mode and service life according to power demand and usage conditions, so as to design, manufacture and use the in-situ power supply system of the seawater dissolved oxygen battery for full sea depth of the present invention.

[0051] The preparation of the electrochemically modified carbon fiber brush composite silver oxygen reduction electrode is specifically described below by way of examples.

[0052] Example 3

[0053] Firstly, 6g of T700SC 12K PAN-based carbon fiber tow and 2g of 1mm diameter titanium wire were woven into a carbon fiber brush electrode; then the carbon fiber brush electrode was placed in a 0.5 M sulfuric acid aqueous solution with an aniline concentration of 0.5 mM, and electrochemically anodic oxidation was performed for 5 minutes at a constant current density of ±2 A / g, and electrochemical cathode reduction was performed for 5 minutes, and then the above process was repeated 5 times to prepare an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface. During this period, the total oxidation charge passed was 3600 C / g (the total charge of 6 electrochemical oxidation processes), and the total reduction charge was 3600 C / g (the total charge of 6 electrochemical reduction processes); finally, the above electrochemically modified carbon fiber brush electrode was placed in a 0.1M silver nitrate solution, and the constant current density was -50 mA / g. The electrochemical reduction deposition time was 1h and the deposition charge was 180 C / g, and finally an electrochemically modified carbon fiber brush composite silver oxygen reduction electrode with nitrogen-containing active functional groups and discontinuous silver particles on the surface was obtained.

[0054] Example 4

[0055] Firstly, 6 g of T800SC 24K PAN-based carbon fiber tow and 2 g of 1.5 mm diameter titanium wire were woven into a carbon fiber brush electrode; then the carbon fiber brush electrode was placed in a 2 M sulfuric acid aqueous solution with an aniline concentration of 2 mM, and electrochemically anodic oxidation was performed for 5 minutes at a constant current density of ±3 A / g, followed by electrochemical cathode reduction for 5 minutes, and then the above process was repeated 3 times to prepare an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface. During this period, the total oxidation charge passed was 3600 C / g (the total charge of 4 electrochemical oxidation processes), and the total reduction charge was 3600 C / g (the total charge of 4 electrochemical reduction processes); finally, the above electrochemically modified carbon fiber brush electrode was placed in a 0.5 M silver nitrate solution, and by changing the current density and deposition time of the electrochemical reduction, electrochemically modified carbon fiber brush composite silver oxygen reduction electrodes with deposited silver charges of 80 C / g, 180 C / g, 280 C / g and 380 C / g were prepared, respectively.

[0056] Example 5

[0057] Firstly, 10 g of T700SC 12K PAN-based carbon fiber tow and 3 g of 2 mm diameter titanium wire were woven into a carbon fiber brush electrode; then the carbon fiber brush electrode was placed in a 1 M sulfuric acid aqueous solution with an aniline concentration of 0.2 mM, and electrochemical anodic oxidation was performed for 10 minutes at a constant current density of ±1 A / g, followed by electrochemical cathode reduction for 5 minutes, and then the above process was repeated 8 times to prepare an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface. During this period, the total oxidation charge passed was 5400 C / g (the total charge of 9 electrochemical oxidation processes), and the total reduction charge was 2700 C / g (the total charge of 9 electrochemical reduction processes); finally, the above electrochemically modified carbon fiber brush electrode was placed in a 0.1 M silver nitrate solution, and the constant current density was -100 mA / g. The electrochemical reduction deposition time was 1 h and the deposition charge was 360 C / g, and finally an electrochemically modified carbon fiber brush composite silver oxygen reduction electrode with nitrogen-containing active functional groups and discontinuous silver particles on the surface was obtained.

[0058] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention; the terms "connection", "installation", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-situ power supply system for seawater dissolved oxygen batteries at full sea depth, characterized in that: It includes a plurality of seawater battery power generation units (3), a DC / DC boost unit (4), an energy storage battery unit (5), a load (6), a backup battery unit (7), a load power supply switch (8), a power management unit (9) and a pressure-resistant cabin (10). The seawater battery power generation unit (3) comprises a magnesium alloy negative electrode (1) and a positive electrode (2) composed of carbon fiber brush electrodes surrounding the negative electrode; Each of the seawater battery power generation units (3) is equipped with an independent DC / DC boost unit (4), which boosts the low voltage 1.0-2.0V output by each of the seawater battery power generation units (3) to a DC / DC boost unit (4) of 5-36V that meets the load requirement, and each seawater battery power generation unit (3) stores the electric energy in the energy storage battery unit (5) after being boosted by the corresponding boost unit (4). Each seawater battery power generation unit (3) and the corresponding boost unit (4) form a power supply line, and the multiple power supply lines are in parallel relationship; The energy storage battery unit (5) adopts a charging and discharging mode to supply power to the load (6) via the load power supply switch (8); When the energy storage battery unit (5) cannot supply power to the load, the backup battery unit (7) supplies power to the load via the load power supply switch (8); The power management unit (9) is used for system monitoring and control, data collection and storage, and real-time data communication; the monitoring and control of the power management unit (9) is to determine the power generation capacity and working state of each seawater battery power generation unit (3) by collecting the output voltage and current of each seawater battery power generation unit (3); to determine the power supply capacity and working state of the energy storage battery unit (5) by collecting the output voltage and current of the energy storage battery unit (5); when it is determined that the capacity of the energy storage battery unit (5) is less than 30%, the load (6) power supply switch is used to switch to the backup battery unit (7) to supply power to the load (6); when it is determined that the capacity of the energy storage battery unit (5) has recovered to 90%, the load (6) power supply switch is used to switch back to the energy storage battery unit (5) to supply power to the load (6); The DC / DC boost unit (4), energy storage battery unit (5), backup battery unit (7), load power supply switch (8) and power management unit (9) are placed together in a pressure-resistant cabin (10); the seawater battery power generation unit (3) and the load (6) outside the pressure-resistant cabin (10) are connected to the inside of the pressure-resistant cabin (10) via a pressure-resistant watertight cable (1).

2. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The open circuit potential of the magnesium alloy negative electrode is negative than -1.7V, and the potential during operation is negative than -1.4V, both of which are relative to a saturated calomel electrode; the utilization rate of the magnesium alloy negative electrode is not less than 50%, and the service life is not less than 1 year.

3. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1 is characterized in that: The output power of the seawater battery power generation unit (1) is 1-10 W, and the volume power density is not less than 5 W / m 3 .

4. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The DC / DC boost unit (4) boosts a DC low voltage of 1.0-2.0V to a DC high voltage of 5-36V, and the boosted energy conversion efficiency is not less than 70%.

5. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The energy storage battery unit (5) is a secondary battery, and its cyclic charge and discharge capacity is a capacity retention rate of more than 85% after 1,500 cycles, and its design capacity is more than 1.5 times the total daily power generation of the multi-channel parallel seawater battery power generation unit (1) and the DC / DC boost unit (4); the backup battery unit (7) is a primary battery or a secondary battery, and its design capacity is more than twice the capacity of the energy storage battery unit (5), and its annual self-discharge rate is less than 10%.

6. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The data acquisition and storage of the power management unit (9) is to acquire and store the following contents: including the output voltage and current of each seawater battery power generation unit (1), the status data of the DC / DC boost unit (4), that is, on is 1, off is 0, the output voltage and current at both ends of the load (6), and the status data of the energy storage battery unit (5) and the backup battery unit (7), that is, on is 1, and off is 0.

7. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The real-time data communication of the power management unit (9) is to send the current or historical data of the seawater dissolved oxygen battery in-situ power supply system to the user via cable, hydroacoustic and network, or hydroacoustic and satellite communication.

8. The in-situ power supply system for seawater dissolved oxygen battery for full sea depth according to claim 1, characterized in that: The positive electrode formed by the carbon fiber brush electrode is an oxygen reduction electrode of electrochemically modified carbon fiber brush composite silver, and is made of raw materials polyacrylonitrile-based carbon fiber tow and titanium wire through weaving to form the carbon fiber brush electrode; The carbon fiber brush electrode is placed in an electrolyte solution containing aniline, and after a cyclic treatment between electrochemical oxidation and electrochemical reduction, an electrochemically modified carbon fiber brush electrode with nitrogen-containing active functional groups on the surface is prepared; the electrochemically modified carbon fiber brush electrode is placed in a silver nitrate solution, and silver is deposited through electrochemical reduction to obtain an electrochemically modified carbon fiber brush composite silver oxygen reduction electrode.

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