CN114068995B

CN114068995B - All-iron oxidation flow battery system

Info

Publication number: CN114068995B
Application number: CN202111381587.1A
Authority: CN
Inventors: 张明刚
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2022-05-20
Anticipated expiration: 2041-11-22
Also published as: CN114068995A

Abstract

The invention discloses an all-iron oxidation flow battery system in the technical field of batteries, which comprises: reaction bin, oxidation bin, pipeline, iron electrode, liquid flow electrode, iron ion electrolyte and oxidizing substance. The iron electrode and the liquid flow electrode are positioned in the reaction bin, the reaction bin and the oxidation bin form a circulating system through a pipeline, iron ion electrolyte in the reaction bin reacts with the iron electrode on the liquid flow electrode to release electric energy, the iron ion is reduced to ferrous ion on the liquid flow electrode, and the iron electrode loses electrons and becomes the ferrous ion to enter the electrolyte. The electrolyte enters the oxidation bin to react with the oxidizing substances, and the oxidized electrolyte circularly enters the reaction bin. According to the invention, the regeneration of the iron ion electrolyte is realized through the oxidation of the oxidation bin, the usage amount of the electrolyte of the positive half cell of the mixed liquid flow battery is reduced, and the improvement of the energy density of the system is realized.

Description

All-iron oxidation flow battery system

Technical Field

The invention belongs to the technical field of batteries, relates to a mixed liquid flow battery system, and particularly relates to an all-iron oxidation flow battery system.

Background

Flow batteries are a battery technology in which an active material is present in a liquid electrolyte. The electrolyte is arranged outside the electric pile, flows through the electric pile under the driving of the circulating pump, and generates electrochemical reaction to realize the conversion between chemical energy and electric energy. The rated power and the rated energy of the flow battery are independent, the power depends on the electric pile, and the energy depends on the electrolyte. The amount of the electrolyte can be increased at will, and the purpose of increasing the capacity of the battery is achieved. Can be discharged deeply without damaging the battery, and can be discharged by 100 percent. The battery has simple structure, low material price and low replacement and maintenance cost. The electrolyte solution is an aqueous solution, so that the battery system has no potential explosion or fire hazard and has high safety. The active material of the flow battery is present in the liquid electrolyte and therefore the energy density is relatively low.

The high-capacity and low-potential metal material is used as the active material of the negative electrode instead of the low-concentration negative electrode electrolyte, and the energy density of the flow battery can be greatly improved although the working characteristics of part of the flow battery are sacrificed. This flow battery configuration, which maintains the flow battery's mode of operation in the positive half-cell, while the negative half-cell uses the conventional battery's mode of operation, is called a mixed flow battery.

The energy density of the mixed liquid flow battery is limited by the electrolyte of the anode half-battery, and the overall energy density is greatly improved, but the energy density of the mixed liquid flow battery does not have good performance compared with the prior mature battery technology. The total cost of the flow battery is still high due to the reaction materials, the diaphragm and other auxiliary devices.

Disclosure of Invention

The present invention is directed to solving at least one of the above problems.

Therefore, the invention aims to provide an all-iron oxidation flow battery system which can realize high specific power, safe and reasonable energy density and economic and efficient conversion efficiency and has the characteristics of low manufacturing cost, environmental safety and convenience in recycling and comprehensive utilization. In order to achieve the purpose, the invention provides an all-iron oxidation flow battery system which comprises a reaction bin, an oxidation bin, a pipeline, an iron electrode, a flow electrode, iron ion electrolyte and an oxidizing substance. The iron electrode and the liquid flow electrode are positioned in the reaction bin, the reaction bin and the oxidation bin form a circulating system through a pipeline, iron ion electrolyte in the reaction bin reacts with the iron electrode on the liquid flow electrode to release electric energy, the iron ion is reduced to ferrous ion on the liquid flow electrode, and the iron electrode loses electrons and becomes the ferrous ion to enter the electrolyte. The electrolyte enters the oxidation bin to react with the oxidizing substances, and the oxidized electrolyte circularly enters the reaction bin. The electrolyte may be subjected to appropriate conditioning in the cycle, which may include, but is not limited to, separating excess electrolyte, replenishing electrolyte components or water, separating precipitates, venting gases. The oxidation bin or the pipeline can contain an electrolyte adjusting device. The pipeline can contain a liquid pump and a valve to adjust the pressure of the electrolyte flowing through the pipeline so as to realize the circulation and control of the electrolyte.

The starting of the battery system needs to open a pipeline for filling electrolyte, and the battery system does not respond to the power utilization starting below the second level and cannot be charged. Can be matched with an external rechargeable battery to meet the requirements of instant electricity utilization response and energy recovery. And the electrolyte in the reaction bin is drained through a pipeline to realize the battery preservation in a long-term non-operation state. The battery operation time is increased by supplementing the iron electrode material, the oxidizing substance and adjusting the electrolyte.

The theoretical value of the electrode voltage of the reaction bin of the battery system is 1.21V, the theoretical value is 0.8V to 1.0V measured in an experiment, and the actual working voltage can be changed according to the difference of the electrode components, the purity, the passivation corrosion degree, the electrolyte concentration and the like. Multiple reaction chambers can be combined in series, parallel or series-parallel to form a battery pack to provide high voltage or large current, and in some embodiments, the oxidation chambers are shared under the condition of ensuring insulation of different potentials, and insulation measures include but are not limited to drip injection, separation after filling and the like.

The oxidation bin of the cell system can take measures to accelerate oxidation according to application scenes, including but not limited to mechanical increase of contact surface and relative flow rate of gas and liquid, catalyst acceleration reaction, over 2 times of area of the reaction bin solarization oxidation, pressurization and humidification to increase solubility of gas oxidation substances, energy recovery of a primary cell and acceleration reaction.

The battery system of the invention takes iron as the cathode, has low price, little pollution, rich source of iron electrode materials, no use of noble metal catalyst, moderate theoretical energy density, long storage life of the battery with mechanically added electrode materials, safe storage and convenient recovery, and is suitable for large-scale application.

The reaction chamber electrode of the battery system of the invention adopts solid-liquid phase reaction, and has large discharge power and high specific power. The oxidation of the ferrous ions in the oxidation bin is fast. The electrolyte two-step reaction provides buffer for discharge to cope with high-power application scenes such as power batteries and the like, the theoretical voltage is reduced to increase the oxidation speed, in some embodiments, the iron-oxygen 1.3V theoretical voltage is reduced to the iron-ferric iron 1.21V theoretical voltage, solid-liquid-gas three-phase reaction discharge is converted into solid-liquid two-phase reaction discharge, alkaline electrolyte is not used, the passivation and polarization of electrodes are small, the internal resistance of the battery is low, and the actual working voltage is reasonably usable.

The battery system of the invention changes the reversibility of the anolyte by the reversibility of the system, and reduces the limit of the volume of the anolyte to the energy density of the system. The anode and the cathode are converted into ferrous ions after reaction, so that the requirement of the diaphragm of the flow battery is lowered, and the cathode does not need an independent electrolyte, so that the system cost is integrally lowered. The iron is used as an electrode, the electronegativity is not as good as that of metals such as lithium, sodium, magnesium, aluminum, zinc and the like, the working voltage is relatively low, and the theoretical energy density limit is close to 1.1 kilowatt-hour per kilogram and is not as good as that of a common metal-air battery. The battery system only consumes iron and a small amount of water after complete circulation, the weight of electrolyte consumed by complexation reaction and the like in most metal-air batteries is avoided, the structure of the battery system is relatively simple, and the proportion of auxiliary substances is acceptable, so that the proportion of effective active substances is high, the actual energy density is expected to reach 500 watt-hour per kilogram, and the battery system has an excellent application prospect.

In some embodiments of the present invention, the oxidizing substance in the oxidation chamber is oxygen in the air, ferrous ions in the electrolyte react with the oxygen in the air to generate ferric ions and generate ferric oxide precipitates, and the oxidized electrolyte enters the reaction chamber through the filter membrane to complete circulation. The electrolyte is not lost in circulation, and the overall reaction is iron and oxygen to form iron oxide. The actual product, yellow iron oxide, contains water molecules and free water, and therefore requires a certain amount of water replenishment. The battery running time can be increased by supplementing the iron electrode material, emptying the iron oxide yellow mud material and supplementing water.

In some embodiments of the present invention, the oxidizing substance in the oxidation chamber is chlorine, ferrous ions in the electrolyte react with the chlorine to generate iron ions, and the oxidized electrolyte enters the reaction chamber to complete the cycle. To maintain the electrolyte in equilibrium in the circuit, ferrous chloride may be separated before oxidation or ferric chloride may be separated after oxidation. One embodiment is matched with a chlor-alkali electrolysis device to realize the hydrogen-caustic soda-ferrous chloride coproduction by using the raw salt, the waste iron and less electric power, or one embodiment which adds the air oxidation to realize the hydrogen-caustic soda-ferrous chloride-ferric oxide yellow coproduction by using the raw salt and the waste iron. The method is matched with a co-production mode to produce high-value products such as hydrogen, caustic soda, ferrous chloride, iron oxide yellow and the like by taking low-price raw salt and waste iron as raw materials, reduces or avoids the consumption of electric power, reduces the investment of variable-voltage rectification equipment, avoids the storage and transportation of toxic gases such as chlorine and the like, and has great development prospect. The electrolysis reaction of the electrolytic cell and the discharge reaction of the battery system can be asynchronously carried out, and the asynchronous time is mainly influenced by the stock solution. Some embodiments are large in scale, can participate in stable control and adjustment of a power grid, and are matched with photovoltaic power, wind power and the like to improve energy structures.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment applied to a power battery according to the present invention.

Fig. 2 is a schematic structural diagram of an embodiment of the invention applied to chlor-alkali co-production.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of an embodiment applied to a power battery according to the present invention. As shown in fig. 1, the all-iron oxidation flow battery system includes: 1. the system comprises a reaction bin, 2 iron ion electrolyte, 3 iron electrode, 4 liquid flow electrode, 5 pressure relief exhaust valve, 6 liquid injection pipe, 7 liquid injection valve, 8 liquid pumping pipe, 9 liquid pump, 10 oxidation bin, 11 liquid storage chamber, 12 oxidation chamber, 13 filter membrane, 14 exhaust port, 15 air inlet, 16 liquid inlet pipe, 17 discharge port, 18 liquid outlet pipe, 19 discharge valve, 20 mud bin and 21 iron yellow mud.

Wherein, the reaction chamber (1) and the oxidation chamber (10) form a circulating system through a pipeline consisting of a liquid pumping pipe (8), a liquid pump (9), a liquid inlet pipe (16), a liquid outlet pipe (18), a liquid injection valve (7) and a liquid injection pipe (6). The iron ion electrolyte (2) in the reaction bin (1) reacts with the iron electrode (3) on the liquid flow electrode (4) to release electric energy, the iron ions are reduced to ferrous ions on the liquid flow electrode (4), and the iron electrode (3) loses electrons to become the ferrous ions which enter the electrolyte. The electrolyte enters an oxidation bin (10) to react with oxidizing substances in an oxidation chamber (12), and the oxidized electrolyte enters a liquid storage chamber (11) through a filter membrane (13) and enters a reaction bin (1) through a liquid outlet pipe (18), a liquid injection valve (7) and a liquid injection pipe (6). In the example, the oxidizing substance is oxygen in air, the air flows in through the air inlet (15) and flows out through the air outlet (14), iron ions are oxidized to generate iron oxide precipitates, the iron oxide precipitates are called iron oxide yellow mud (21), and the iron oxide yellow mud enters the mud bin (20) through the discharge hole (17) and the discharge valve (19).

The pressure relief vent valve (5), the filter membrane (13), the discharge port (17), the discharge valve (19), the mud bin (20), etc. in this example should be considered as accessories of the corresponding equipment, and in some embodiments can be removed or used in other forms, and should not be considered as limiting the invention.

Fig. 2 is a schematic structural diagram of one embodiment of the invention applied to chlor-alkali co-production. As shown in fig. 1, the all-iron oxidation flow battery system includes: 1. the device comprises a reaction chamber, 2 iron ion electrolyte, 3 iron electrode, 4 liquid flow electrode, 5 pressure relief exhaust valve, 6 liquid injection pipe, 7 liquid injection valve, 8 liquid pumping pipe, 9 liquid pump, 10 oxidation chamber, 11 liquid storage chamber, 12 oxidation chamber, 13 air isolation filter membrane, 14 air return pipe, 15 air inlet pipe, 16 liquid inlet pipe, 17 ferrous chloride liquid separation valve, 18 liquid outlet pipe, 19 iron chloride liquid separation valve, 20 air pump, 21 chlorine gas extraction pipe, 22 chlor-alkali electrolytic tank and 23 current collection distribution box.

Wherein, the reaction chamber (1) and the oxidation chamber (10) form a circulating system through a pipeline consisting of a liquid pumping pipe (8), a liquid pump (9), a liquid inlet pipe (16), a liquid outlet pipe (18), a liquid injection valve (7) and a liquid injection pipe (6). The iron ion electrolyte (2) in the reaction bin (1) reacts with the iron electrode (3) on the liquid flow electrode (4) to release electric energy, the iron ions are reduced to ferrous ions on the liquid flow electrode (4), and the iron electrode (3) loses electrons to become the ferrous ions which enter the electrolyte. The electrolyte enters an oxidation bin (10) to react with oxidizing substances in an oxidation chamber (12), and the oxidized electrolyte enters a liquid storage chamber (11) through an air-isolating filter membrane (13) and enters a reaction bin (1) through a liquid outlet pipe (18), a liquid injection valve (7) and a liquid injection pipe (6). In this example, the oxidizing substance is chlorine gas electrolytically generated by a chlor-alkali cell (22). Chlorine gas is sucked by the air pump (20) through the chlorine gas suction pipe (21), flows into the air return pipe (14) through the air inlet pipe (15) and flows back to circulate. Iron ions are oxidized, chlorine is reduced and then enters the electrolyte, no precipitate is generated, and the total amount of the electrolyte is increased. The redundant ferric chloride solution can be separated through a ferric chloride liquid separating valve (19), and the ferrous chloride stock solution can also be separated through a ferrous chloride liquid separating valve (17), and the ferrous chloride stock solution can react with iron to refine ferrous chloride. The electric energy discharged from the liquid flow electrode (4) and the iron electrode (3) is connected into a current-collecting distribution box (23) to obtain the voltage which is in accordance with the chlor-alkali electrolysis to supply power for the chlor-alkali electrolysis cell (22) through combined switching and control, and the insufficient electric quantity can be provided by a power grid or a battery system of other embodiments of the invention. This example achieves hydrogen-caustic soda-ferrous chloride co-production with raw salt, waste iron and less electricity. One embodiment of adding air oxidation realizes the hydrogen-caustic soda-ferrous chloride-iron oxide yellow co-production by using raw salt and waste iron. The co-production system reduces or avoids the consumption of electric power on the whole and reduces the investment of the transformation rectifying equipment. Chlorine generated by chlor-alkali electrolysis is consumed by a battery system immediately, and the storage and transportation of the chlorine are avoided. The large-capacity liquid storage space is used, chlorine generated by electrolysis of the electrolytic cell when the electric energy of the power grid is surplus can be absorbed, the battery system discharges back to the power grid when the electric energy of the power grid is insufficient, the discharge power of some embodiments is large in scale, the energy structure can be improved by participating in stable control and regulation of the power grid and matching with photovoltaic, wind power and the like.

In this example, the pressure relief vent valve (5), the filter membrane (13), the ferrous chloride dispensing valve (17), the ferric chloride dispensing valve (19), the air pump (20), the chlorine gas extraction pipe (21), the chlor-alkali electrolysis cell (22), the current collecting distribution box (23) and the like should be regarded as accessories or external devices of corresponding devices, and in some embodiments, can be removed or used in other forms, and should not be regarded as limitations of the present invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An all-iron oxidation flow battery system, comprising: the device comprises a reaction bin, an oxidation bin, a pipeline, an iron electrode, a liquid flow electrode, iron ion electrolyte and an oxidizing substance, wherein the iron electrode and the liquid flow electrode are positioned in the reaction bin, the reaction bin and the oxidation bin form a circulating system through the pipeline, the iron ion electrolyte reacts with the iron electrode in the reaction bin to release electric energy, the iron ion is reduced to ferrous ion on the liquid flow electrode, the iron electrode loses electrons and becomes the ferrous ion to enter the electrolyte, the electrolyte enters the oxidation bin to react with the oxidizing substance, and the oxidized electrolyte circulates to the reaction bin.

2. The all iron oxidation flow battery system of claim 1, wherein the piping comprises a liquid pump and a valve.

3. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the reaction bins are connected in series, in parallel or in series and parallel to form a battery pack.

4. The all iron oxidation flow battery system of claim 1 or 2, wherein the oxidation bin or conduit comprises a precipitation separation device.

5. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the oxidation bin or pipeline contains an electrolyte separation device.

6. The all iron oxidation flow battery system of claim 1 or 2, wherein the oxidation silo or piping contains a means for replenishing electrolyte components or water.

7. The all iron oxidation flow battery system of claim 1 or 2, wherein the oxidation bin or conduit comprises a vent.

8. The all iron oxidation flow battery system of claim 1 or 2, wherein the oxidation silo contains a means to mechanically increase the reaction area and relative flow rate.

9. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the oxidation bin has an area more than 2 times that of the reaction bin.

10. The all-iron oxidation flow battery system of claim 1 or 2, wherein the oxidation bin contains an oxidation reaction catalyst.

11. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the oxidation chamber is provided with a device for increasing the solubility of the gas oxidizing substance by pressurizing and humidifying the gas oxidizing substance.

12. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the oxidation bin has a galvanic cell arrangement of ferrous ions and an oxidizing substance.

13. The all-iron oxidation flow battery system according to claim 1 or 2, wherein the oxidizing substance in the oxidation bin is oxygen in air.

14. The all-iron oxidation flow battery system of claim 1 or 2, wherein the oxidizing species in the oxidation compartment is chlorine gas.