Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04276—Arrangements for managing the electrolyte stream, e.g. heat exchange
  • H01M8/04283—Supply means of electrolyte to or in matrix-fuel cells
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/02—Process control or regulation
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
  • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/8605—Porous electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/8605—Porous electrodes
  • H01M4/8621—Porous electrodes containing only metallic or ceramic material, e.g. made by sintering or sputtering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/96—Carbon-based electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/08—Fuel cells with aqueous electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/14—Fuel cells with fused electrolytes
  • H01M8/143—Fuel cells with fused electrolytes with liquid, solid or electrolyte-charged reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
  • H01M8/184—Regeneration by electrochemical means
  • H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/20—Indirect fuel cells, e.g. fuel cells with redox couple being irreversible
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0002—Aqueous electrolytes
  • H01M2300/0005—Acid electrolytes
  • H01M2300/0011—Sulfuric acid-based
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the invention relates to a specific cell structure for electrochemical cells of the flow type, which has a minimized pressure loss compared to a conventional cell structure and further shows a significantly improved flow distribution within the cell. In addition, better performance is achieved with the electrochemical cell than with cells having a conventional cell construction.
• Energy storage is becoming increasingly important, especially in connection with the changing production of energy.
• Of particular interest are such examples that offer the opportunity to store large amounts of energy and to deliver and record them with high performance.
• Preference is given to technologies that turn on and off the energy with the highest possible efficiency, so that as little energy as possible is lost and thus cost-effective intermediate storage can take place.
• FIG. 1 A much discussed technology for this purpose are the redox flow memory.
• FIG. 1 A general illustration of this prior art technology is shown in Figure 1.
• the energy is stored in the electrolyte in the form of metals, salts or other chemical compounds, these compounds being in liquid, dispersed or dissolved form.
• the electrolytes are stored in external tanks la, lb.
• For charging or discharging the electrolytes are pumped through an electrochemical cell 2.
• electrical energy is converted into chemical energy by applying a voltage via a mains connection 5 to the respective electrodes 3 a, 3 b through oxidation and reduction reactions during charging and is converted back into electrical energy during discharging.
• the following reactions generalize at the electrodes: Minus pole:
• the electrochemical cell 2 consists of two half cells, the anode side and the cathode side, in which the respective electrodes 3a, 3b are contained. Both half-cells are separated by a permeable separation layer 4 for charge balance during charging and discharging. To increase the performance z. B. several such individual cells are combined into so-called stacks or cell stacks or the active area of the individual cells can be increased.
• the performance of a single cell with a given active area is determined from the combination of cell voltage and current density, ie the maximum power per area. This applies to both directions of the reversible reaction.
• Electrodes are required with the highest possible power density per cell electrodes are required with the highest possible surface area.
• the performance of a cell is determined, among other things, by the number of electrochemical reactions per time and the geometric cell area [mol / (s * m 2 )]. Electrodes with a large surface area per geometric surface thus have many active sites where the electrochemical reactions can proceed.
• three-dimensional porous electrodes such as metal foams or highly porous carbon fleeces used, but also other materials are possible.
• electrode is equated in this application with the term "three-dimensional porous electrode”.
• FIG. 2 shows a standard construction of such a redox flow cell of the prior art.
• These electrodes 6a, 6b are integrated together with a permeable separating layer 4 into a cell frame and flow through the anolyte 8a or catholyte 8b in the X or Y direction during charging and discharging, so that on the surface of the electrodes 6a, 6b, the oxidation or reduction reactions take place.
• the electrodes 6a, 6b are thereby delimited from the side elements 7 to the outside.
• the side elements have next to a demarcation to the outside in a cell stack the task of forwarding the stream from one cell to the next.
• the state-of-charge (SOC, state of charge) of the electrolyte decreases in the same direction during discharge or when charging, so that the electrode, the side member and the permeable Separation layer on the entire surface sees a different concentration of the respective active species. If, for each residence time of the electrolyte in the cell, an excessive change in the SOC is achieved, then on the one hand the individual components, such as. As the permeable separation layer, the electrode and the Seitlelement claimed differently at different locations, which can easily men to irreversible damage to the respective components.
• German patent application DE 3401638 AI Hoechst
• electrolysis cells with liquid electrolytes and porous electrodes in which the electrolyte enters parallel to the electrode surface and is forced by at least one throttle point to flow at least partially parallel to the flow of charge through the electrode.
• redox flow cells are flown from one side of the electrodes and the electrolyte flows through the electrodes in the X or Y direction (see FIG. 2) and leaves the cell again on the opposite side. Since the electrodes used cause a high flow resistance for the electrolyte, thereby inevitably occur pressure losses, which make an up-scaling of the cell simultaneously in the X and Y direction technically and economically very difficult to impossible. Such a high pressure loss in large cells on the one hand would require technically complex and expensive concepts and on the other hand would also pose a security risk. Furthermore, to overcome the pressure drop, a pumping power would be needed which would reduce the overall system efficiency to an unacceptable extent.
• the object of the present invention was therefore to reliably avoid the disadvantages known from the prior art and to provide an alternative solution for an electrochemical cell of the flow type, by means of which the pressure loss within the cell is reduced, the current density is increased and a more even flow through the electrode is ensured.
• the electrolyte should have as uniform as possible a charge state over the height and at the same time across the width of the cell, in order to reduce the probability of undesirable side reactions.
• the subject matter of the invention is a flow-through electrochemical cell comprising
• A An anode and a cathode half cell, which are bounded by side elements, and which are contained in the half-cells, the respective porous electrodes, as well as (B) a permeable separation layer, which is arranged between the anode and the cathode half cell, which is characterized in that
• the electrolyte is present over the height and width of the cell with a greatly different state of charge.
• the likelihood of side reactions over the entire area of the cell is the same and thereby the maximum change in the SOC of the electrolyte per residence time in the cell can be achieved and can also be operated at much higher current densities, resulting in a lower volumetric flow is necessary, thus less pump power and thus a higher system efficiency can be achieved.
• the flow-through type electrochemical cell according to the invention can be flowed through by liquids or by gases or both.
• inorganic or organic acids are used as solvents, with preference given to using aqueous sulfuric acid.
• aqueous sulfuric acid As possible redox couples, titanium, iron, chromium, vanadium, cerium, zinc, bromine and sulfur are used.
• the cell according to the invention it is also possible to use the cell according to the invention as a zinc-air energy storage, so that the cell is flowed through by a zinc slurry and air or oxygen.
• Other such applications are conceivable in which a salt dissolved in a liquid in an electrochemical cell is electrochemically reacted and the formation of a gas is not the main reaction.
• the electrochemical cell according to the invention may be an electrolysis cell in single-cell construction, the so-called “single cell elements", as disclosed for example in DE 196 41125 AI (Uhdenora), or a type of filter press type, as exemplified in EP 0095039 A1 (Uhde)
• the side elements are monopolar elements and the electrochemical cells of the filter press type are bipolar elements, the respective side elements preferably being used as plates and particularly preferably as bipolar plates.
• the permeable separating layer is selected from the group comprising permeable membranes, selectively permeable membranes, semi-permeable membranes, diaphragms, ultrafiltration membranes and ceramic separators.
• the electrolyte inflow region between the permeable separating layer and the porous electrode and the electrolyte outflow region are arranged between the permeable separating layer and the side elements or vice versa.
• the electrolyte inflow region and / or the electrolyte outflow region are integrated into the porous electrodes and / or the side elements by means of one or more flow channels.
• the flow channels can be arranged parallel to each other in the porous electrode or the side elements or intersect. Any arrangement of flow channels is conceivable.
• a coarse-meshed support structure is provided in the electrolyte inflow region and / or in the electrolyte outflow region.
• This coarse-meshed support structure is preferably a woven fabric or a knitted fabric or another component which ensures a defined distance between permeable separating layer and electrode and offers a low flow resistance.
• the same embodiment of the coarse-meshed support structure or another coarse-meshed support structure is used in the electrolyte inflow region and in the electrolyte outflow region.
• This coarse-meshed support structure is also called a percolator.
• the coarse mesh support structure is made of an electrically conductive material or a material with a conductive coating, which is preferably a carbon support structure. But other materials can be used. In this case, the coarse-meshed support structure has a lower flow resistance than the porous electrode and is stable with respect to the electrolyte.
• the material is sufficiently electrically connected to the porous electrode and also has a good electrical connection to the side elements. This tissue can be saved if the side elements and / or the porous electrode are provided with corresponding flow channels, which ensure an unhindered outflow of the electrolyte and establish a sufficient electrical connection with the electrode.
• At this support structure may preferably, but not necessarily, also take place redox reactions.
• the porous electrode is advantageously a carbon nonwoven, a foam, or a metal foam. Other materials can be used.
• the structure can be extended by further layers which lead either to a more uniform electrolyte distribution or to an improved cell performance, ie to a higher current density, a higher efficiency or a better or more uniform current distribution or the like, or show other advantages. It is also possible that the cathode and anode half cell of a single cell differ from the structure or the structure of the two half-cells is symmetrical. Furthermore, the present invention relates to cell stacks of a flow-through type electrochemical cell as described in the opening paragraph.
• the present invention also encompasses a method for operating a flow-through electrochemical cell, which is characterized in that electrolyte flows through a porous electrode perpendicular to the permeable separating layer.
• the method is realized such that
• electrolyte is supplied via an electrolyte inflow region, which is connected to an electrolyte feed,
• the electrolyte is led out of the cell via an electrolyte outflow region disposed on the opposite side of the porous electrode to the electrolyte inflow region.
• Figure 1 Schematic representation of a redox flow memory from the state of
• Figure 2 Schematic structure of a prior art redox flow cell.
• Figure 3 Schematic structure of an electrochemical cell according to the invention, in which the porous electrodes are flowed through perpendicular to the permea ble separation layer.
• FIG 4 Schematic structure of another inventive Shen electrochemical cell in which the porous electrodes are flowed through perpendicular to the permeable separation layer.
• FIG. 5 Different arrangements of the components of an electrochemical cell according to the invention.
• Figure 6 Three-dimensional representation of an electrochemical cell according to the invention, which contains the different arrangements of the components, as shown in FIGS. 5a, b, c.
• FIGS. 3 and 4 show electrochemical cells 9 according to the invention.
• electrolyte 8a, 8b flows via an electrolyte feed 13a, 13b into an electrolyte inflow region 10, which is arranged between permeable separating layer 4 and porous electrode 3a.
• electrolyte inflow region 10 is a coarse-meshed support structure 11, which is also referred to as a percolator.
• the electrolyte inflow region 10 has a closed end 12 at the end of the electrochemical cell facing the electrolyte inlet.
• inflowing electrolyte 8a, 8b is forced perpendicularly to the permeable separating layer 4, ie in the z-direction, through the porous electrode 3a, 3b.
• the electrolyte 8a, 8b When the electrolyte 8a, 8b flows into the electrolyte inflow region 10 filled with a support structure 11, it first fills uniformly with electrolyte 8a, 8b. Thereafter, the electrolyte 8a, 8b flows uniformly through the porous electrode 3a, 3b, which offers a greater flow resistance than the support structure 11. From there, the electrolyte 8a, 8b flows into an electrolyte outflow region 14, in which a further coarse-meshed support Structure 15 is provided, which consists of the same or a different material, such as the support structure 11 in the electrolyte inflow region 10. Thereafter, the electrolyte 8a, 8b leaves the electrochemical cell 9 through an electrolyte drain 16.
• Figure 4 differs from Figure 3 only in that the electrolyte Ausström Scheme 14 is integrated into the side member 7 via flow channels 17. The support structure can then be dispensed with.
• FIG. 5 shows different arrangements of the components in an electrochemical cell, which is traversed perpendicular to the permeable separating layer.
• FIG. 5 a shows the porous electrode 6 a, 6 b with integrated flow channels 17 for the inflow region 10 as well as for the outflow region 14.
• the electrolyte inflow region 10 is realized via a coarse-meshed support structure 11, and the flow channels 17 are incorporated into the porous electrode 6a, 6b.
• FIG. 5c the electrolyte inflow region 10 and the electrolyte outflow region 14 are represented by flow channels 17.
• the flow channels 17 of the electrolyte inflow region 10 are located in the porous electrode 6a, 6b, and the flow channels of the electrolyte outflow region 14 are located in the side elements 7.
• the shape and arrangement of the flow channels can be chosen arbitrarily.
• FIGs 6a, 6b and 6c the arrangements of components of an electrochemical cell shown in Figures 5a, 5b and 5c are shown in three-dimensional view.
• the view is shown on the side of the electrochemical cell from which electrolyte is carried out via an electrolyte drain 16 and in the lower area of the figure 19, the view of the side of the electrochemical cell is shown, from the electrolyte over one Electrolyte inlet 13 flows into the cell.
• the pressure loss in a prior art cell having an active area of 1 m 2 with dimensions of 1 mx 1 m can be calculated as follows.
• Pressure loss volume flow * viscosity * length / (permeability * Q.section area)

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Sustainable Energy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Ceramic Engineering (AREA)
• Automation & Control Theory (AREA)
• Fuel Cell (AREA)
• Inert Electrodes (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=49080893

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (18)

Citations (11)

Family Cites Families (14)

• 2012
  • 2012-09-03 DE DE102012017306.7A patent/DE102012017306A1/de not_active Ceased
• 2013
  • 2013-08-29 CA CA2883457A patent/CA2883457C/en not_active Expired - Fee Related
  • 2013-08-29 US US14/424,901 patent/US9680172B2/en not_active Expired - Fee Related
  • 2013-08-29 CN CN201380045871.9A patent/CN104620432B/zh not_active Expired - Fee Related
  • 2013-08-29 KR KR1020157008577A patent/KR20150052249A/ko not_active Ceased
  • 2013-08-29 EP EP13753648.8A patent/EP2893586B1/de not_active Not-in-force
  • 2013-08-29 WO PCT/EP2013/067954 patent/WO2014033238A1/de not_active Ceased
  • 2013-08-29 JP JP2015529030A patent/JP6336449B2/ja not_active Expired - Fee Related

Patent Citations (11)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events