FLOW BATTERY, PROCESS FOR THE MANUFACTURE, AND USE THEREOF Technical Field

[0001] The invention pertains to a flow battery, particularly a metal-air flow

battery.

Background Art

[0002] In electrochemistry and electrochemical engineering, by flow battery or redox flow battery (after reduction-oxidation ) is meant a kind of battery where rechargeability is provided by two chemical components dissolved in liquids contained within the system and separated by a membrane. Because flow batteries can be rapidly“recharged” by replacing the electrolyte, they are increasingly considered for application in battery electric vehicles (BEV), as is pointed out in DUNLAP, Richard A.

Sustainable Energy. Stamford: Cengage Learning, 2015. ISBN

1133108776. p.495. An overview and classification of this battery type is presented in NOACK, Jens, et al. The Chemistry of Redox-Flow Batteries. Angew. Chem., int Ed. Engi.. 26 June 2015, vol.54, no.34, p.9776-9809.

[0003] US 5445901 A (KORALL MENACHEM [IL] ET AL) 29.08.1995 discloses a multi-cell, sealed, zinc-oxygen battery, comprising a container containing (a) a plurality of bi-cells, each cell having a housing provided with two major surfaces and accommodating a pair of oppositely-disposed, spaced- apart, air-permeable, liquid-impermeable cathodes in the form of oxygen- reduction electrodes, and defining between themselves a cavity configured to accommodate an anode of the battery and electrolyte, substantial portions of the major surfaces of the housing being removed, thus exposing major portions of the oxygen electrodes, and wherein the two major surfaces are partly recessed in such a way as to form, in conjunction with a similarly-recessed outer surface of a major wall of an adjacent cell housing, an inter-cathode gas space between adjacent cells with a plurality of oxygen access openings leading thereto; (b) a dead space volume between inner surfaces of the housing and the plurality of bi-cells; and (c) pressurized oxygen supply means for feeding oxygen to the dead space volume, for consumption in the inter-cathode gas spaces.

[0004] Taylor Vortex Flow galvanic electrochemical cells such as batteries, flow cells and fuel cells for converting chemical energy into electrical energy and comprising a cylindrical spinning particulate filter between static cylindrical current collectors for use with electrolytes containing galvanic charge transfer particles functioning as numerous miniature electrodes and means for pumping electrolyte through the filter to produce

accelerated reaction electrochemistry for higher cell power density are disclosed in US 2014255812 A (FISCH EL HALBERT [US]) 11.09.2014 .

[0005] US 4714662 A (BENNETT WILLIAM R [US]) 22.12.1987 discloses a power module of the type including a plurality of power cells arranged in a longitudinal stacked relation. Each power cell includes a frame, a gas- consuming cathode supported at one end of the frame and a consumable anode supported intermediate the ends of the frame by a flexible diaphragm spanning the frame. The diaphragm divides the frame into a chamber for the introduction thereinto of an electrolyte between the anode and the cathode, and an expansion chamber on the opposite side of the anode for the introduction thereinto of fluid under pressure. The pressurized fluid biases the anode toward the cathode during anode consumption, and the diaphragm provides for longitudinal and angular movement of the anode to accommodate uneven corrosion of the anode. The frames of adjacent cells define a third chamber therebetween for the introduction of consumable gas to the cathode. An array of manifolds is formed throughout the frames of adjacent power cells for introducing electrolyte between the anode and the cathode, for introducing

consumable gas to the cathode and for introducing fluid under pressure to the expansion chamber.

[0006] WO 2015009029 A (H2 INC [KR]) 22.01.2015 relates to a redox flow battery or fuel cell stack assembled by stacking a plurality of plates provided with a passage through which an electrolyte passes, the redox flow battery or fuel cell stack comprising a plurality of electrolyte tubes inserted in the electrolyte passages, ion exchange membranes, and flow frames disposed at either side of the ion exchange membranes, wherein each flow frame has an electrolyte flow path formed therein and one end of each of the plurality of electrolyte tubes comes in contact with each of the electrolyte flow paths.

Summary of invention

[0007] The invention aims to provide an improved flow battery.

Technical Problem

[0008] State-of-the-art flow batteries suffer from drawbacks such as congestion of their electrodes, defects in liquid tightness, or shunt currents, all of which may lead to efficiency drop.

Solution to Problem

[0009] The problem is solved by the characterizing features of the independent claims.

Advantageous effect of invention

[0010] The modular approach as per the invention allows for a dramatic increase in energy density, shortening of charge time, and cost-efficient production. Embodiments of the invention are set out in the dependent claims.

[0011] Particularly, a reduction of sealing surfaces may be achieved to avoid

leakage. Such leakage poses a major problem with known flow batteries, where components such as air electrode, separator, bipolar plate, and circuitry need to be stacked and mutually sealed. In these conventional batteries, the use of different materials of varying porosity and surface texture typically impedes the implementation of a seal that is free from leakage. Additionally, the separator film used in these devices tends to roll away, further complicating the stacking procedure.

[0012] Another embodiment provides for the introduction of energizing elements into the channel structure to enhance fluid flow by avoiding dead water areas, calculus generation, or clogging, increase turbulence and ionic conductivity, and improve clustering as well as hydrogen bonding. These improvements in turn lead to an increased self-cleaning capacity of the air electrode, ultimately resulting in an extended service life of the resulting battery.

[0013] Said energizing elements may possess various characteristics and consist of materials such as synthetics, ferromagnetic and other metals, crystals, and further constituents selected to affect clustering in water. Preferably, such elements are of a streamlined, flat shape that offers light flow resistance while introducing turbulence into the fluid flow, thus promoting mixing. This way, metal particles carried axially in the fluid without prior conductor contact may be pressed against the channel wall where they can undergo the desired reaction.

[0014] Advantageously, the structural, conceptional, material, and procedural aspects of the invention render the proposed battery suited as a torsionally rigid tube for light-weight design. Here, its multi-chambered ducts may serve a dual purpose both as a structural and functional element. In this application, the inventive approach facilitates a massive increase in energy density compared to conventional flow batteries: In the latter case, the reactor, failing to contribute to the supporting structure, essentially constitutes dead mass when incorporated into a vehicle or other mobile apparatus. By contrast, an embodiment of the invention permits a highly scalable BEV design. When filled with ionic fluid, the battery may even achieve a cooling effect.

[0015] Furthermore, the uniform structure inherent to an embodiment of the

invention allows for a significant reduction in manufacturing expenses by eliminating a large part of the production costs associated with

conventional battery stacks. Firstly, its modular layout applies broadly to a variety of form factors and particularly provides for a series connection of arbitrary voltage. To this end, any number of ducts may be arranged in a planar structure such as the floor panel of a battery electric vehicle.

Secondly, its manufacture does not require a dust-free clean room or otherwise controlled level of contamination, as is typically the case with conservative metal-air flow batteries. Thirdly, the proposed battery may be manufactured additively by means of so-called 3D printing. Fourthly and lastly, a worn-out battery as per the invention may be given a second life by remanufacturing or recycling any useable ducts in a factory

environment.

Brief description of drawings

[0016] Figure 1 is a transversal section of a battery duct.

[0017] Figure 2 is a longitudinal section of a chamber of the duct.

[0018] Figure 3 is a plan view of the duct.

[0019] Figure 4 is an exploded view of a battery.

Description of embodiments

[0020] One way of carrying out the invention claimed is hereinafter described at detail.

Example

[0021] Figure 1 shows a multi-chambered duct (100) comprising an insulating and lye-proof outer frame (102) of polypropylene and a conducting inner frame (101) encased therein. The inner frame (101) forms a first

chamber (105) containing an air electrode (111), the first chamber (105) separated by a first partition wall (107) from a second chamber (103) filled with aerial oxygen or ionic liquid (not depicted). An impermeable second partition wall (108) seals the second chamber (103) from a third

chamber (104) charged with zinc slurry (not depicted), which chamber in turn is divided from a fourth chamber (106) by a third partition wall (109). The first wall (107) and third wall (109), both of which are partly perforated, exhibit pores ranging from 100 nm to 5 pm in diameter. Opposite the third partition wall (109), the outer frame (102) forms a perforated outer wall (110) that delimits the fourth chamber (106) and encloses the electrolyte (not depicted) flowing therethrough. Also, the outer frame (102) exhibits complementarily formed regions (112, 113) that may be used for plugging the duct together with further ducts (100) of the same or similar shape and size.

[0022] As may be taken from Figure 2, the third or fourth chamber (200)

comprises energizing elements (201) for guiding the fluid flow passing through it. Herein, each duct (300) exhibits an essentially uniform cross section such as the one shown in Figure 3. [0023] An advantageous process for the manufacture of a flow battery (400) based on such ducts (100, 300, 401 ) is now described. To this end, a conductor may be extruded into stock that forms the chambers and walls therebetween, of which the first wall (107) and third wall (109) are laser- perforated. Next, a gas diffusion layer (GDL) and catalysis layer are wet- laid into the first chamber (105) and compressed with each other under a given pressure, these layers now jointly constituting the air

electrode (1 1 1 ). Upon curing and pyrolyzing the latter, the stock is encased in a lye-proof insulator and broken down into ducts (100, 300, 401 ) such that the conductor forms the inner frame (101 ) and the insulator forms the outer frame (102) of each duct. The flow battery (400) may now be finalized by mutually plugging the ducts (100, 300, 401 ) together in a serial connection and plugging joining elements (402) bilaterally onto the ducts (100, 300, 401 ). The resulting panel can be welded between two thin shell elements (406, 407) for use as a support element in a car body. Figure 4 shows an exploded view of a battery based on the ducts of the invention.

Industrial applicability

[0024] The invention is applicable throughout, inter alia, the electricity and

manufacturing - especially automotive - industries.

Reference signs list

[0025]

100 Duct

101 Inner frame

102 Outer frame

103 Second chamber

104 Third chamber

105 First chamber

106 Fourth chamber First (partition) wall

Second (partition) wall Third (partition) wall

Outer wall

Air electrode

Complementarily formed region Complementarily formed region Third or fourth chamber Energizing element

Duct

Flow battery

Duct

Joining element

Air, ionic fluid, or electrolyte

Metal slurry

Ionic fluid or electrolyte

Shell element

Shell element

Citation list

[0026] The following documents are cited throughout this document.

Patent literature

[0027] US 5445901 A (KORALL MENACHEM [IL] ET AL) 29.08.1995

[0028] US 2014255812 A (FISCH EL HALBERT [US]) 11.09.2014

[0029] US 4714662 A (BENNETT WILLIAM R [US]) 22.12.1987

[0030] WO 2015009029 A (H2 INC [KR]) 22.01.2015

Non-patent literature

[0031] NOACK, Jens, et al. The Chemistry of Redox-Flow Batteries. Angew.

Chem., Int Ed. Engl.. 26 June 2015, vol.54, no.34, p.9776-9809.

DUNLAP, Richard A. Sustainable Energy. Stamford: Cengage Learning, 2015. ISBN 1133108776. p.495.