Device architecture for metal-air batteries

Abstract

Systems and methods of various embodiments can provide device architectures for battery packs. In various embodiments, these can be primary battery packs or secondary battery packs. In various embodiments, these devices can be used for energy storage. Various embodiments can provide a battery comprising an oxygen reduction reaction (ORR) electrode, an oxygen evolution reaction (OER) electrode, a metal electrode, and an electrolyte separating the ORR electrode and the OER electrode from the metal electrode.

Description

[0001] Related applications This application claims priority to U.S. Provisional Patent Application No. 62 / 868,479, filed June 28, 2019, entitled “Device Architecture for Metal-Air Battery Pack”, and U.S. Provisional Patent Application No. 63 / 021,301, filed May 7, 2020, entitled “Device Architecture for Metal-Air Battery Pack”, the entire contents of which are incorporated herein by reference for all purposes. Background Technology

[0002] Energy storage technology is playing an increasingly important role in the power grid; at its most basic level, these storage resources provide smoothing to better match the grid's generation and demand. Services provided by energy storage devices benefit the grid across multiple timescales, from milliseconds to years. Today, existing energy storage technologies can support timescales from milliseconds to hours, but long-duration and ultra-long-duration (generally at least ≥8 hours) energy storage systems are still needed.

[0003] Metal-air battery packs are an attractive option for electrochemical energy storage due to the low cost and abundance of air as a reagent in their energy storage reactions. Many challenges associated with the development of metal-air battery packs are related to mechanical cell architecture. Some architectures are suitable for small-scale storage, such as zinc-air hearing aid battery packs, but not for large-scale energy storage applications such as grid-connected power generation.

[0004] This background section is intended to introduce various aspects of the art that can be associated with embodiments of the present invention. Therefore, the foregoing discussion in this section provides a framework for a better understanding of the invention and should not be construed as an admission of prior art. Summary of the Invention

[0005] Systems and methods in various implementations can provide device architectures for battery packs. In various implementations, these can be primary or secondary battery packs. In various implementations, these devices can be used for energy storage.

[0006] Various embodiments may provide a battery pack including an oxygen reduction reaction (ORR) electrode, an oxygen evolution reaction (OER) electrode, a metal electrode, and an electrolyte that separates the ORR electrode and the OER electrode from the metal electrode. In various embodiments, the ORR electrode and the OER electrode are part of the same single air electrode. In various embodiments, the ORR electrode and the OER electrode are separate electrodes. In various embodiments, the ORR electrode floats on the surface of the electrolyte, and the OER electrode is immersed in the electrolyte. In various embodiments, the battery pack includes a stackable container that supports the ORR electrode, the OER electrode, the metal electrode, and the electrolyte, wherein the stackable container is configured to self-stack on other stackable containers. In various embodiments, the ORR electrode is corrugated or wavy. In various embodiments, the housing of the battery pack serves as a current conductor for the metal electrode. In various embodiments, the ORR electrode and the OER electrode are immersed in the electrolyte. In various embodiments, the ORR electrode is supported in a frame that moves the electrolyte to create a gas volume at a depth below the electrolyte surface. In various embodiments, the ORR electrode comprises a box-shaped structure filled with air. In various embodiments, the ORR electrode is supplied with air. In various embodiments, the ORR electrode is curved. In various embodiments, the ORR electrode is supported in a frame that traps the supplied air in an air chamber defined by the surface of the ORR electrode. In various embodiments, the ORR electrode is tubular. In various embodiments, the ORR electrode is a series of two or more ORR electrodes immersed in the electrolyte, the series of ORR electrodes arranged perpendicularly to each other in a stack, and the supplied air bubbles move upward from each lower ORR electrode in the stack to the next higher ORR electrode. In various embodiments, the ORR electrodes are angled relative to each other in the stack. In various embodiments, the ORR electrode includes a baffle located at the higher edge. In various embodiments, the ORR electrode includes channels that allow bubbles to flow upward to the next ORR electrode. In various embodiments, the stack is vertically aligned. In various embodiments, the stacking is vertically staggered. In various embodiments, the ORR electrode is configured as a cylindrical core surrounded by the metal electrode, and the OER electrode is configured as a hexagonal tube surrounding and containing the metal electrode having the ORR electrode. In various embodiments, the ORR electrode, the OER electrode, and the metal electrode are configured as one of a series of similar cells arranged in a cell array within the battery pack.In various embodiments, the electrolyte is an electrolyte pool, and the battery array is immersed in the electrolyte pool. In various embodiments, the metal electrode is configured to change position relative to the ORR electrode and the OER electrode. In various embodiments, the metal electrode is a direct reduced iron pellet bed. Attached Figure Description

[0007] The accompanying drawings, incorporated herein and constituting a part of this specification, illustrate exemplary embodiments of the claims and, together with the general description above and the detailed description below, serve to interpret the features of the claims. Figure 1A A portion of the battery pack in the implementation scheme is shown.

[0008] Figures 1B-1D Cell architectures with floating ORR electrodes according to various implementation schemes are shown.

[0009] Figure 1E and Figure 1F The diagram shows a container design that can be used with various battery architectures.

[0010] Figures 2A-2B Battery architectures with floating ORR electrodes according to various implementation schemes are shown.

[0011] Figure 3 It shows Figures 2A-2B Additional details of the battery pack in the proposed implementation scheme.

[0012] Figures 4A-4C Alternative battery architectures with vertical ORR electrodes are shown according to various implementation schemes.

[0013] Figure 5A Cross-sectional side views of battery packs according to various embodiments are shown. Figure 5B Alternative configurations based on various implementation schemes are shown.

[0014] Figure 6 A battery pack including a vertical ORR electrode is shown according to various embodiments.

[0015] Figure 7A and Figure 7B A battery including a vertical ORR electrode is shown according to various embodiments.

[0016] Figure 8 and Figure 9B Vertical and horizontal architectures according to various implementation schemes are shown respectively.

[0017] Figure 9A A lid system for a container is shown in the embodiment.

[0018] Figures 10A-10C Flat, corrugated, and wavy ORR electrode architectures according to various implementation schemes are shown respectively.

[0019] Figure 11 A battery pack with a metal container—a negative electrode—and a slot is shown according to various embodiments.

[0020] Figures 12A-12F Disc-shaped battery architectures for providing mechanical integrity are shown according to various implementation schemes.

[0021] Figure 13 Stackable architectures according to various implementation schemes are shown.

[0022] Figure 14 The reverse intake architecture according to various implementation schemes is shown.

[0023] Figure 15 A reverse-inspiratory ORR electrode assembly is shown according to various embodiments.

[0024] Figure 16 Another reverse-inhalation ORR electrode assembly is shown according to various embodiments.

[0025] Figure 17 and Figure 18 An inhalation electrode without a protruding oxygen bag structure is shown according to various embodiments.

[0026] Figure 19A and Figure 19B Side and top views of another reverse-intake battery pack design according to various embodiments are shown respectively.

[0027] Figures 20A-23 Tubular ORR electrode assemblies according to various embodiments are shown.

[0028] Figure 24 Bottom-opening reverse-suction ORR electrode designs are shown according to various implementation schemes.

[0029] Figures 25A-25B Aspects of column design according to various implementation schemes are shown.

[0030] Figures 26A-26B Alternative aspects of column design according to various implementation schemes are shown.

[0031] Figures 27-34 The core ORR electrode configurations with further stacking are shown according to various implementation schemes.

[0032] Figures 35A-35CAspects of the stacked core ORR electrode configurations according to various implementation schemes are shown.

[0033] Figures 36A-36B Aspects of the stacked core ORR electrode configurations according to various implementation schemes are shown.

[0034] Figures 37-43 The effects of applying different levels of air pressure to the air jet electrode according to various implementation schemes are shown.

[0035] Figure 44 Spiral ORR electrode designs according to various implementation schemes are shown.

[0036] Figures 45-47B Various linear ORR electrode configurations according to various implementation schemes are shown.

[0037] Figures 48-49 Diagrams and snorkel cup designs based on various implementation schemes are shown.

[0038] Figure 50 A cross-sectional side view of a test tube design according to various implementation schemes is shown.

[0039] Figure 51 A cross-sectional side view showing the repose angle variation of the ORR electrode according to various embodiments is shown.

[0040] Figure 52 The movable anode design according to various implementation schemes is shown.

[0041] Figure 53A and Figure 53B Cross-sectional side and top views of the battery pack according to various embodiments are shown respectively.

[0042] Figure 54 A cross-sectional side view of an intake electrode according to various embodiments is shown.

[0043] Figure 55 A cross-sectional side view of a reverse-intake electrode of an immersion electrode according to various embodiments is shown.

[0044] Figure 56 A cross-sectional side view of a sparged air electrode according to various embodiments is shown.

[0045] Figure 57 A cross-sectional side view of the stacked jet air electrode assembly is shown.

[0046] Figure 58 A cross-sectional side view of stacked and staggered jet air electrode assemblies according to various embodiments is shown.

[0047] Figure 59 A perspective view of a rectangular tubular ORR electrode design according to various implementation schemes is shown.

[0048] Figure 60 A perspective view of a cylindrical tubular ORR electrode design according to various implementation schemes is shown.

[0049] Figure 61 A perspective view of a cylindrical tubular ORR electrode array in a container according to various embodiments is shown.

[0050] Figure 62 A perspective view is shown of a cylindrical tubular ORR electrode design with a vertical seam formed from a wrapped monosheet, according to various embodiments.

[0051] Figure 63A and Figure 63B The rigid OER cathode and flexible ORR cathode of the implementation scheme are shown.

[0052] Figure 64 Stacked ORR electrode configurations according to various implementation schemes are shown.

[0053] Figure 65 ORR electrodes including porous spacers are shown according to various embodiments.

[0054] Figure 66A A horizontal ORR electrode that is not on the same horizontal plane as the electrolyte is shown.

[0055] Figures 66B-66E Examples of passive and active level control systems according to various implementation schemes are shown.

[0056] Figure 67A The vertically aligned electrode assembly is shown.

[0057] Figure 67B and Figure 67C Interdigitated electrode assemblies with various implementation schemes are shown.

[0058] Figure 68 An embodiment of a dual ORR and OER electrode configuration is shown, wherein the OER electrode is bent to create an air bag volume for the ORR electrode.

[0059] Figures 69A-69N Examples of bubble control methods according to various implementation schemes are shown.

[0060] Figures 70A-70C The OER and separator configuration is shown.

[0061] Figure 71A and Figure 71BThe gas multi-branch configuration of the embodiment is shown.

[0062] Figure 72A An unsealed vertical immersion cathode according to one embodiment is shown.

[0063] Figure 72B It shows Figure 72A The pressure difference at the cathode.

[0064] Figure 72C and Figure 72D It shows the control Figure 72A Methods for controlling air pressure in chambers or other unsealed air chambers.

[0065] Figure 73 A sealed, horizontally submerged electrode is shown in the embodiment.

[0066] Figure 74A and Figure 74B The co-located ORR and OER electrode configuration of the embodiment is shown.

[0067] Figure 75 The packaging configuration of an ORR electrode according to one embodiment is shown.

[0068] Figures 76A-76D Cross-sectional views of concave horizontal ORR electrodes in various embodiments are shown.

[0069] Figure 77A , Figure 77B and Figure 77C A comparison of different configurations of pressurized air chambers for balancing electrolyte pressure at the ORR electrode is shown.

[0070] Figures 78A-85C Aspects of unsealed, horizontal, submerged ORR electrode and reactor designs according to various embodiments are shown.

[0071] Figures 86A-87C The bubble flow characteristics in the UHS reactor of the embodiment are shown, as well as the configuration of the UHS reactor of the embodiment.

[0072] Figures 88A-88S Exemplary aspects of a sealed vertically submerged ORR electrode according to various embodiments are shown, including flow fields that can be used in those embodiments.

[0073] Figure 89 An exemplary aspect of an unsealed horizontally submerged ORR electrode according to various embodiments is shown.

[0074] Figure 90 An exemplary container for a repeating ORR electrode assembly is shown.

[0075] Figure 91A , Figure 91B and Figure 91C Examples of pressure gradient mitigation for sealed ORR electrodes according to various implementation schemes are shown.

[0076] Figure 92 The design and process for compressing a large DRI pellet bed into an anode-current collector assembly using a passive mechanical locking feature are shown.

[0077] Figure 93 The design and process for compressing a large DRI pellet bed into an anode current collector assembly using a threaded rod and a threaded nut or lock nut are shown.

[0078] Figures 94-102 Various exemplary systems are shown, in which one or more aspects of various implementations can be used as part of a large-capacity energy storage system. Detailed Implementation

[0079] Various embodiments will be described in detail with reference to the accompanying drawings. Where possible, the same reference numerals will be used throughout the drawings to refer to the same or similar components. References to specific embodiments and implementations are for illustrative purposes and are not intended to limit the scope of the claims. The following description of embodiments of the invention is not intended to limit the invention to these embodiments, but rather to enable those skilled in the art to make and use the invention.

[0080] As used herein, unless otherwise stated, the room temperature is 25°C. C. Furthermore, the standard temperature and pressure are 25. C and 1 atmosphere. Unless otherwise expressly stated, all tests, test results, physical properties, and values ​​dependent on temperature, pressure, or both are provided at standard ambient temperature and pressure.

[0081] Generally, unless otherwise stated, the term “about” as used herein is intended to include ±10% of the variance or range, the experimental or instrumental error associated with obtaining the value, and preferably the larger of these.

[0082] As used herein, unless otherwise stated, the detailed enumeration of ranges of values ​​herein is intended only as a shorthand method for individually referring to each individual value falling within that range. Unless otherwise stated herein, each individual value within a range is incorporated into the specification as if it were listed separately herein.

[0083] The following embodiments are provided to illustrate various implementations of the system and method of the present invention. These embodiments are for illustrative purposes and may be suggestive, and should not be considered limiting or otherwise restrictive of the scope of the invention.

[0084] It should be noted that no theoretical basis is required to provide or resolve novel and inventive processes, materials, properties, or other beneficial features and characteristics that are the subject matter of or associated with embodiments of the invention. However, various theories are provided in this specification to further advance the art in this field. The theories presented in this specification, unless expressly stated otherwise, do not in any way limit, constrain, or narrow the scope of protection claimed by the claimed invention. The use of this invention does not require or practice these theories. It should also be understood that this invention may lead to new, previously unknown theories to explain the functional features of embodiments of the methods, articles, materials, apparatus, and systems of the invention; and these subsequently developed theories should not limit the scope of protection claimed by the invention.

[0085] The various embodiments of the systems, apparatus, techniques, methods, activities, and operations described herein can be used in a variety of other activities and fields besides those described herein. Furthermore, these embodiments can be used, for example, in other apparatus or activities that may be developed in the future; and in existing apparatus or activities that can be modified in part according to the guidance of this specification. Moreover, the various embodiments and examples described herein can be used in whole or in part in combination with each other, and can be used in various different combinations. Therefore, for example, the configurations provided in the various embodiments of this specification can be used interchangeably; and the scope of protection claimed by this invention should not be limited to the specific embodiments, embodiments, or arrangements described in the specific drawings.

[0086] Embodiments of the present invention include apparatus, systems, and methods for long-term and ultra-long-term, low-cost energy storage. In this document, "long-term" and / or "ultra-long-term" can refer to energy storage cycles of 8 hours or longer, such as 8-hour energy storage cycles, 8-20-hour energy storage cycles, 20-hour energy storage cycles, 20-24-hour energy storage cycles, 24-hour energy storage cycles, 24-hour to one-week energy storage cycles, one-week to one-year energy storage cycles (e.g., days to weeks to months), etc. In other words, "long-term" and / or "ultra-long-term" energy storage batteries can refer to electrochemical batteries that can be configured to store energy over time spans of days, weeks, or seasons. For example, an electrochemical battery can be configured to store energy generated by solar cells during the summer when sunlight is abundant and solar power generation exceeds grid demand, and release the stored energy during the winter when sunlight is insufficient to meet grid demand. Long-term energy storage systems can also be referred to as LODES (Long-Term Energy Storage Systems).

[0087] Figure 1AA portion of a battery pack 100 according to an embodiment is shown, such as a metal-air battery pack. The battery pack 100 (e.g., a metal-air battery pack) includes a first negative electrode 110 (hereinafter referred to as anode 110), a first positive electrode 120 (generally referred to as cathode), an electrolyte 140, and a casing 170.

[0088] In various embodiments, the electrolyte 140 is a liquid. In various embodiments, the anode 110 is a solid, and the electrolyte 140 is excluded from the anode. In various other embodiments, the anode 110 is porous, and the electrolyte 140 is geometrically dispersed with the anode 110, thereby creating a larger interfacial surface area for the reaction. In various embodiments, the cathode 120 is porous, and the electrolyte is geometrically dispersed with the anode 110, thereby creating a larger interfacial surface area for the reaction. In various embodiments, the cathode 120 is located at the interface between the electrolyte and the gaseous headspace 105. In various embodiments, the gaseous headspace is sealed within a housing 170. In various other embodiments, the housing 170 is unsealed, and the gaseous headspace is an open system that can freely exchange substances with the environment.

[0089] The anode 110 can be formed of a metal or metal alloy, such as lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), silicon (Si), aluminum (Al), zinc (Zn), or iron (Fe); or an alloy substantially composed of one or more of the aforementioned metallic elements, such as aluminum alloys or iron alloys (e.g., FeAl, FeZn, FeMg, etc.), which can undergo an oxidation reaction to discharge. Therefore, the anode 110 may be referred to herein as a metal electrode. In some embodiments, the battery pack is rechargeable, and the metal electrode undergoes a reduction reaction when the battery pack is charged. The anode 110 can be a solid (including dense or porous solids), a mesh or foam, or particles or an aggregate of particles, or it can be a slurry, ink, suspension, or paste deposited within the housing 170. In various embodiments, the composition of the anode 110 can be selected such that the anode 110 and a volume of liquid electrolyte 140 do not mix together. For example, the anode 110 can be a metal electrode, which can be a blocky solid. As another embodiment, the anode 110 may be an aggregate of particles (e.g., small or large particles) within the suspension, whose buoyancy is insufficient to cause them to escape from the suspension into the electrolyte. As another embodiment, the anode 110 may be formed from particles that do not float in the electrolyte.

[0090] The cathode electrode (sometimes called the air electrode) 120 supports the reaction with oxygen at the positive electrode. The cathode 120 can be a so-called gas diffusion electrode (GDE), where the cathode is solid and located at the interface between the gas headspace 105 and the electrolyte 140. During discharge, the cathode 120 supports the reduction of oxygen from the gas headspace 105, a so-called oxygen reduction reaction (ORR). In some embodiments, the battery pack 100 is rechargeable and a reverse reaction occurs, where the cathode 120 supports the evolution of oxygen from the battery pack, a so-called oxygen evolution reaction (OER). OER and ORR reactions are well known to those skilled in the art.

[0091] In some embodiments, cathode 120 is a single electrode that supports ORR only, and the battery pack is a primary (discharge-only) metal-air battery pack. In some other embodiments, cathode 120 is a single electrode that supports both ORR (discharge reaction) and OER (charge reaction), and the metal-air battery pack is rechargeable (secondary battery pack). Cathode 120 can be a single air electrode, i.e., a "dual-function electrode," which operates in both OER and ORR modes, or it can be a combination of two electrodes, i.e., a "dual electrode," where one electrode is configured to operate in OER mode and the other electrode is configured to operate in ORR mode.

[0092] In various embodiments, electrolyte 140 is a liquid. In some embodiments, electrolyte 140 is an aqueous solution, a non-aqueous solution, or a combination thereof. In various embodiments, electrolyte 140 is an aqueous solution that can be acidic (low pH), neutral (medium pH), or basic (high pH; also called alkaline or caustic base). In some embodiments, liquid electrolyte 140 may include positively charged elements, such as Li, K, Na, or combinations thereof. In some embodiments, the liquid electrolyte may be alkaline, i.e., pH greater than 7. In some embodiments, the electrolyte has a pH greater than 10, and in other embodiments, the electrolyte has a pH greater than 12. For example, electrolyte 140 may include 6 M (mol / L) potassium hydroxide (KOH). In some embodiments, electrolyte 140 may include, for example, a combination of 5.5 M potassium hydroxide (KOH) and 0.5 M lithium hydroxide (LiOH). In some embodiments, electrolyte 140 may include 6 M (mol / L) sodium hydroxide (NaOH). In some embodiments, electrolyte 140 may include sodium hydroxide (NaOH) at a concentration of 5 M (mol / L) and potassium hydroxide (KOH) at a concentration of 1 M.

[0093] In some embodiments, the battery pack 100 (e.g., a metal-air battery pack) discharges by reducing oxygen (O2) typically derived from the air. This requires a three-phase contact between gaseous oxygen, an electronically active conductor that provides electrons for the reduction reaction, and an electrolyte 140 containing the products of the reduction step. For example, in some embodiments involving an aqueous alkaline electrolyte, oxygen from the air is distributed via a half-reaction... It is reduced to hydroxide ions. Therefore, supplying oxygen to a metal-air battery requires gas handling and maintenance of the triple point. In some embodiments, referred to as a “normal air-breathing” configuration, the cathode 120 is mechanically positioned at the gas-liquid interface to facilitate and maintain the triple-phase boundary. The cathode 120 can be placed vertically or horizontally relative to gravity, or at any intermediate angle, while maintaining the “normal air-breathing” configuration. In these “normal air-breathing” configurations, the gas phase is at atmospheric pressure (i.e., unpressurized outside of gravity).

[0094] Figures 1B-1E and Figures 2A-2B A battery architecture according to various embodiments is shown, which has a floating ORR electrode on top. As one example, Figures 1B-1D and Figures 2A-2B The configuration of the medium architecture can be referenced. Figure 1A The battery pack system 100 (e.g., a metal-air battery pack) described herein is a component of one or more battery packs 100. In various embodiments, the battery pack 100 may be, for example, Figure 1B , Figure 1C and Figure 1D In the illustrated stackable container configuration, each battery pack 100 can represent a stackable container 150, with a housing 170 configured to support other containers 150 when stacked together. The self-stacking nature of the containers 150 can provide a system architecture that increases plant power density (MW / acre). The stacked containers can be designed with conductive contact points, allowing the stacked cells to make electrical contact and be connected in series with each other. In one embodiment, the containers are wider and longer than their height, resulting in enhanced structural stability, reduced pressure gradients within the containers, and increased surface area for thermal management. In other embodiments, the containers can be approximately as tall as their width or length to achieve maximum container surface area, or they can be much taller than their width or length to save floor space.

[0095] A container housing battery pack components can perform multiple functions in a single economical part. Its primary function is to contain the electrolyte. This electrolyte is a hazardous liquid requiring a secondary containment structure to trap any leakage should the primary container fail. Other functions of the container may include conducting waste heat or insulating the electrochemical components, or electrically insulating the components. In some embodiments, the container may include a double-walled container, such as a double-walled container formed by rotational molding. In one embodiment, an example is described in… Figure 1E and 1F As shown, inner wall 160 is the main battery container. Figure 1E A partial perspective sectional view of the main battery container is shown. Figure 1F It shows in Figure 1F On the left side is a side sectional view of the running battery with component 165 inserted, and in Figure 1F The right-hand side shows a side sectional view of a battery in maintenance mode with component 165 replaced. The outer wall 162 is separated from the inner wall 160 by a cavity 161. The outer wall 162 serves as a secondary containment for the inner container. The cavity 161 can also be used for other additional functions, such as providing an additional air gap for electrical insulation or thermal management of the battery assembly 165. Thermal management can be accomplished by allowing fluid (e.g., air) to flow through the cavity 161. The inner wall 160 and outer wall 162 can be connected to flanges 163. These flanges 163 are formed in a manner that provides optimal fluid flow for thermal management. The total material usage of a double-walled container is less than that of a single-walled container and an additional secondary containment. If the cavity 161 is not used as the sole secondary containment, it can also be filled with different fluids to provide other functions, such as increasing thermal mass by filling with a liquid (e.g., water) or allowing liquid to flow through the cavity 161 for thermal management. Thirdly, the cavity 161 can also be used for maintenance purposes. If the electrolyte 164 must be drained to maintain the battery assembly 165, a suitably sized cavity accommodates the electrolyte 164 from the battery while the assembly 165 is being maintained. After maintenance, the electrolyte 164 is pumped back into the main container 166. The advantage is that no additional storage capacity or piping needs to be maintained on-site for maintenance purposes.

[0096] In some implementations, the container's structure and containment function are achieved by different parts. In one implementation, a robust bag for containing the electrolyte and battery contents is located within the structural container. The bag is strong enough to withstand the pressure of the electrolyte, while the box is strong enough to withstand the weight of the bag. This "bag-in-box" container eliminates the need for an expensive structural container. The box can also serve as a temporary secondary containment container in case the bag leaks or ruptures.

[0097] Electrolyte 140 and anode 110 can be supported in container 150. For example... Figure 2AAs shown, in some embodiments, the battery pack 100 may be configured such that the cathode 120 is a dual electrode having an adsorbed ORR electrode 230 floating on an electrolyte 140 above the anode 110 and an OER electrode 220 immersed in the electrolyte 140. Figure 2B Another view of the floating ORR electrode 230 is shown. Figure 3 A cross-sectional side view of container 150 is shown. (As shown) Figure 3 As shown, the anode can be a packed bed of pellets (or marbles), for example, formed of iron, such as direct reduced iron (DRI).

[0098] Figure 4A Alternative battery architectures with vertical ORR for “neutral inhalation” are shown according to various embodiments. Figure 4A The container 400 shown can be similar to the reference. Figures 1B-2B The described container, except that container 400 may have two anode beds 410 (e.g., two DRI beaded anode beds). An OER cathode 420 and a current collector may be disposed between the anode beds 410. Container 400 may include electrode spacers 416 (e.g., ORR-anode, anode-OER), an anode containment and current collector structure 415, a face seal 450 (e.g., an EPDM gasket), two ORR cathodes 430, an ORR current collector 432, and electrolyte conduits and venting channels 460. In some embodiments, the electrode spacers may prevent dissolved oxygen or oxygen bubbles from reaching the anode without significantly increasing the resistance of the electrochemical cell. In some embodiments, the oxygen barrier spacers may maintain suitable hydrophilicity and high porosity to not impede ion transport between the anode and air electrode. In another embodiment, the ORR electrode may include a hydrophobic layer embedded with conductive carbon particles, which may introduce conductivity into the gas diffusion layer of the ORR electrode. In such embodiments, sheet-like current collectors may be placed on both sides of the ORR electrode to conduct electrons out of the reactor, which can reduce cell resistance.

[0099] In some embodiments, the ORR electrode can be sealed within a chamber of electrolyte (e.g., 6 M KOH) by sandwiching a flexible rubber gasket 452 (e.g., EPDM) between a rigid electrode 453 and a current collector 451 (e.g., Ni-coated steel), for example as... Figure 4B As shown. In such an embodiment, a compressive force can be applied to component 454, causing gasket 452 to compress and deform to form a seal and electrical connection between electrode 453 and current collector 451. Under a compressive load (L), gasket 452 deforms a distance (dx), creating a compression seal and bringing current collector 451 into contact with electrode 453, as shown in three cross-sectional views of the ORR electrode portion. Figure 4CAs shown. The additional compressive force improves the contact between the current collector 451 and the electrode 453, which can reduce the contact resistance that occurs in the electrochemical cell.

[0100] Figure 5A A cross-sectional side view of a battery pack 500 according to various embodiments is shown. The battery pack 500 may be similar to the battery pack 100 described above. The battery pack 500 may be a dual-cathode battery pack, comprising mechanically distinct charging and discharging cathodes, i.e., a pair of OER electrodes 520 and ORR electrodes 530. The dual-cathode design allows for separation of the length dimensions of charging and discharging. Figure 5B Another configuration is shown, in which the pair of OER electrodes 520 and ORR electrodes 530 are separated from each other. (Reference) Figure 5A and Figure 5B As shown, the OER and ORR electrodes do not need to be co-located or electrically connected to each other. If necessary, the OER and ORR electrodes can be electrically isolated via a toggle switch 550. Electrically isolating the OER electrode from the ORR electrode prevents the ORR electrode from being exposed to high operating potentials that could damage or oxidize it. In such an implementation, the OER and ORR electrodes can be constructed from different materials, each optimized separately for OER or ORR. The geometry of each electrode can be independently customized to optimize the performance and cost of the OER and ORR electrodes individually. The OER and ORR electrodes do not need to exhibit the same physical dimensions or microstructure. The pair of OER electrodes 520 can extend downwards along the length of the anode 110 into the electrolyte 140. The OER electrode can be submerged in the electrolyte to maximize the interfacial contact area between the OER electrode and the electrolyte. The ORR electrode 530 can float and / or suspend at the liquidus line 141 of the electrolyte 140. The ORR electrode can be located at the gas / liquid interface to maximize the length of the three-phase boundary (gas-solid-electrolyte boundary) within the electrode material. The thickness of anode 110 may be limited by ion or electron and / or electrochemical kinetics. For the ion / electron transport limit, Lc (Lcharge) can be a length scale perpendicular to the anode of the pair of OER electrodes 520, while Ld (Ldischarge) can be a length scale perpendicular to the anode of ORR electrode 530. Lc and Ld do not need to be equal. For symmetrical charge / discharge durations (in constant mA / cm2), 2 Lc can be twice the size of Ld.

[0101] The length dimensions (e.g., thickness) of the battery pack electrodes are determined and optimized based on their transport characteristics (e.g., conductivity, ionic conductivity), structural characteristics (active material volumetric loading, porosity, tortuosity), and operating conditions (current density, temperature, airflow rate) to meet certain cost / performance / lifetime requirements. In some implementations, the OER and ORR cathodes are configured in parallel. In these cases, the electrodes have a characteristic length dimension (thickness). A second example architecture with perpendicular ORR and OER electrodes embodies this design. The other two length dimensions of the anode are determined by other considerations, such as container size, current collection cost, and heat generation.

[0102] In some other embodiments, the OER and ORR cathodes are not parallel, or even perpendicular. In these configurations, there are two independently defined length dimensions. The length dimension in the discharge direction is determined by the discharge duration, while the length dimension in the charging direction is determined by the charging duration. This allows for the fabrication of metal-air battery packs with independently adjustable charging and discharging durations by adjusting the electrode thickness in two independent dimensions. For example, with parallel OER and ORR electrodes, a KOH electrolyte, and a duration of 300 hours, the anode can be approximately 3 cm to 5 cm thick; the other two dimensions are unconstrained. For perpendicular OER and ORR electrodes, the anode can be approximately 3 cm to 5 cm in the direction perpendicular to the ORR electrode and approximately 10 cm in the dimension between the OER electrodes; the third dimension is unconstrained. This is referred to as a “symmetric duration” configuration. In some other embodiments, the device is designed such that the charging and discharging durations are not equal; this is referred to as an “asymmetric duration” configuration. For example, the device can be configured such that the anode has a 5 cm × 5 cm square cross-section. In this configuration, the device has a charging duration of, for example, approximately 100 hours, and a discharging duration of approximately 300 hours. Many other example configurations are possible for independently adjustable charging and discharging durations.

[0103] In some other embodiments, the gas phase is pressurized to support an increase in the oxygen partial pressure (pO2), which provides a greater driving force for the discharge reaction. In some other embodiments, the pressure is adjustable, allowing pO2 to increase during discharge and decrease during charging, thereby always maximizing the thermodynamic driving force for the desired reaction. In some embodiments, pO2 during discharge can be from 0.01 atm to 100 atm. In some embodiments, pO2 during charging can be from 0.001 atm to 100 atm.

[0104] While standard getter configurations are mechanically simple, they have several drawbacks. Most specifically, because the metal-air system must be open relative to gas mass transport, they are prone to electrolyte drying. As the electrolyte evaporates from the battery, the liquid level shifts, posing a challenge to maintaining a stable three-phase boundary in the air cathode. Therefore, the standard getter design presents a challenge to system stability. Furthermore, air electrodes with hydrophobic coatings can only withstand limited pressure differentials; otherwise, "breakdown pressure" will lead to leakage across the coating. In configurations with vertical or near-vertical air electrodes, gravity-hydraulic pressure heads can be significant, generating large driving forces for liquid migration through the air electrode, leading to air electrode overflow. Additionally, in secondary battery implementations, the oxygen evolution reaction (OER) process generates oxygen bubbles that can become trapped between the air electrode and the liquid electrolyte, drying the electrode and eliminating the triple point. Therefore, the positioning of the air electrode at the air-electrolyte interface is crucial, but maintaining one side of the thin electrode wet and the other dry is challenging.

[0105] Figure 6 , Figure 7A and Figure 7B A dual-cathode battery pack including a vertical ORR electrode 730 is shown according to various embodiments. Specifically, the getter cathode can be placed on top of the electrolyte 140, but if deeper immersion at the iron anode 750 is required, the cathode can be placed vertically, provided its hydrophobic layer can withstand the pressure of the electrolyte 140. Figures 6-7B As shown, the ORR electrode 730 is placed vertically in the concave electrode structure 732, so it can still be in contact with the ambient air above the electrolyte 140. Figure 7A and Figure 7B The iron anode 750 in the battery pack can be stacked, such as a stack of DRI beads, and the OER electrode 720 can be immersed in the electrolyte 140. Figure 6 A close-up view of an ORR electrode 730 is shown. Figure 7A This is a sectional view at line A. Figure 7B It is a top view.

[0106] Figure 8 and Figure 9BVertical 805 and horizontal 905 architectures according to various implementations are shown respectively. The vertical 805 arrangement can support bubble release, reduce the risk of ORR drying out, allow ORR overflow, and can accommodate relatively high cell heights. The vertical 805 arrangement may face challenges related to: pressure-based pinhole leakage, force-based penetration leakage, the need for face seals or other edge seals, the need for drain lines, and the presence of numerous sealing interfaces. The horizontal 905 arrangement can use few (or no) seals, requires minimal pressure holding for the ORR electrodes, and allows for refilling maintenance. The horizontal 905 arrangement can act as a bubble trap, may face ORR drying out or ORR overflow issues, and may require cell-to-cell stacking.

[0107] The battery pack system consists of multiple batteries connected in series and / or in parallel in a bath of a shared electrolyte 140, and is contained within a container 970. Figure 9A The example shown requires multiple auxiliary support systems and needs to be connected in series and / or in parallel with adjacent devices of similar structure. It may also be necessary to protect the battery containing container 970 from the external environment. The cost of installing and commissioning these devices should be low to support system-level economics. One solution is a multi-functional cover 902 that performs all relevant support system functions while also establishing a DC electrical connection to adjacent reactors and environmentally protecting the contents of container 970. Container 970 can be a simple electrolyte and battery container, while the multi-functional cover 902 maintains more complexity as needed. Functions performed by the multi-functional cover 902 and the devices contained within it may include air distribution, exhaust of process gases via vent 903, thermal management, current collection, reactor control and sensing, and DC electrical connection. The multi-functional cover 902 may include a handle for lifting the multi-functional cover 902 from container 970.

[0108] In embodiments with a vertical architecture, the electrodes can be easily accessed, for example, for maintenance, through means such as a cover 900 that covers the electrolyte 140 and can perform other electrical and mechanical functions. The positive electrode assembly (e.g., the pair of OER electrodes 520 or ORR electrodes 530) can be freely or rigidly suspended from a bracket attached to the cover 900. Freely suspended electrodes allow gravity to maintain vertical alignment and keep the electrode assembly under tension rather than compression, which may be advantageous for mechanical design. The electrode assembly can slide into a slot, such as a T-slot, or hang on a rack similar to the operation of a typical filing cabinet rack. The negative electrode can be mounted to a container 970 opposite the cover 900 so that when the cover 900 and the attached positive electrode are lifted and removed from the container 970 (e.g., for easy maintenance of the positive electrode assembly), the electrode remains submerged in the electrolyte and is protected from air contact. When the cover 900 is lifted from the container 970, the positive electrode assembly is attached thereto, and individual electrode assemblies can be more easily replaced or removed for individual maintenance. This design can have additional benefits, namely, allowing more electrolyte 140 to flow at the bottom and sides of the reactor, for example, to mitigate the effects of thermal expansion constant mismatch in the material; to limit the effects of thermal cycling on the material; and to create channels for the continuous directional flow of electrolyte through the reactor.

[0109] A floating air electrode assembly, featuring an adjustable electrode height relative to the free liquid interface and a variable angle of the air electrode relative to gravity, requires only slight hydrophobicity to provide a stable gas-liquid interface and promote bubble overflow from the free liquid interface electrode surface. This floating air electrode assembly naturally self-positions at the liquid-gas interface and can move to accommodate changes in electrolyte height due to evaporation, etc. This ability to adapt to electrolyte height changes allows the device to resist overflow and dry-out problems, maintaining the required triple point. For this purpose, the ORR electrode can be floating or buoyant, thus ensuring it remains aligned with the free interface and maintains the triple boundary. In one embodiment, the ORR electrode can use a low-density material or a "float" to provide buoyancy. In another embodiment, the ORR electrode or its housing can use air instead of the electrolyte, employing the same principle of buoyancy as in ship buoyancy.

[0110] In some embodiments, the evaporation of the electrolyte from the electrochemical cell into the surrounding environment can be reduced by covering the surface of the electrolyte with inert plastic spheres. In such embodiments, the inert plastic spheres may be composed of polymers, such as polypropylene or HDPE. In some embodiments, the spheres may be solid, porous, or hollow, such that the effective density of the spheres is less than the density of the electrolyte, which allows the spheres to float on top of the electrolyte. In another embodiment, the inert spheres can reduce the rate of alkaline atomization from the electrolyte into the surrounding environment.

[0111] Figures 10A-10C Flat ORR electrode 1030, corrugated ORR electrode 1032 and wavy ORR electrode 1034 according to various embodiments are shown respectively. Figures 10A-10C Each of these diagrams illustrates an ORR electrode with a different geometry attached to the housing 170 via a seal 1070. To maximize the system's packing density and energy density, the getter electrode can be mechanically corrugated or folded to increase the area at the three-phase boundary while retaining the natural getter architecture. In such an implementation, the ORR electrode must be able to withstand a smaller hydraulic head (relative to the vertical direction) but retain many of the advantages of a vertical ORR electrode (bubble tolerance). The ORR electrodes can have the same footprint (i.e., the straight-line length from seal 1070 to seal 1070), but corrugated ORR electrode 1032 and wavy ORR electrode 1034 can have a larger surface area in contact with the electrolyte 140 than the flat ORR electrode 1030. The different path lengths of corrugated ORR electrode 1032 and wavy ORR electrode 1034 can result in more three-phase boundary points for corrugated ORR electrode 1032 and wavy ORR electrode 1034 than for the flat ORR electrode 1030.

[0112] Overflow in the ORR electrode reduces oxygen intake, leading to inefficient operation. A self-buffering system can be designed for horizontally inhaled ORR electrodes to passively remove electrolytes or accumulated water from the inhaled surface.

[0113] In some system configurations, getter ORR electrodes can float on the surface of the electrolyte to maintain the three-phase boundary. The electrode needs to self-position itself on the free liquid surface, which proves that current collection is challenging. In some implementations, springs and / or other shaped current collectors can provide current and mobility to the electrode.

[0114] In some embodiments, the casing 170 is made of a polymer, such as polyethylene, high-density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMW), polypropylene, or other polymers. In some other embodiments, the casing 170 is made of a metal, such as nickel, steel, anodized aluminum, nickel-plated steel, nickel-plated aluminum, or other metals. In some embodiments, when the casing is made of metal, the negative electrode is positioned in electrical communication with the casing, forming a so-called "metal container-negative electrode" design. In some embodiments, the metal casing or a portion of the casing allows for electrical continuity between stacked batteries, thereby forming gravity-driven series or parallel connections.

[0115] Figure 11A battery pack with a metal container—the negative electrode—and a trough, according to various embodiments, is shown. In some configurations of this embodiment, the casing 170 may act as a current collector for the anode 110. The metal is rigid enough to contain all the active material within the battery and thick enough to conduct current with low resistive loss, yet remains thin enough to keep costs reasonable. For safety reasons, the exterior of the battery may require sufficient insulation 1170, but external conductive surfaces can allow electrical contact between the batteries.

[0116] In systems with two air electrodes instead of a single bifunctional air electrode, each air electrode can be optimized independently of the other for optimal performance, including but not limited to the material and implementation of each electrode. For example, to optimize the implementation of each OER and ORR electrode, the size of each electrode can be determined based on mutually independent comparative performance and cost. The two cathodes do not need to be co-located or adjacent to each other. In some implementations, the OER electrode (charge cathode) is fully immersed in the liquid electrolyte to maximize the interfacial area available for the reaction, while the ORR electrode is positioned along the gas-liquid interface to maximize the amount of the three-phase boundary. The two cathodes can be always electrically connected, always electrically isolated, or connected via a switching device to allow for dynamic adjustment of the electrical configuration.

[0117] In some implementations, a single housing may contain multiple batteries that are ionically separated from each other by partition walls, which may be electrically insulating.

[0118] In various implementations, the container is elongated in one dimension, resembling a trough or gutter. In some implementations, the bottom surface is dish-shaped to provide additional mechanical integrity. Figure 12A-12F Disc-shaped battery architectures for providing mechanical integrity are shown according to various implementation schemes. Figure 12A and Figure 12B The perspective view and front view of container 1270 are shown respectively. Container 1270 is elongated in one dimension L to form the front view (i.e., Figure 12B The tank observed has an inverted V-shaped cross-section. Container 1270 can hold liquid electrolyte 1240, in which OER electrode 1220 is immersed or partially immersed. Figures 12C-12E The top view, side view and perspective view of the V-shaped container 1271 are shown respectively. Figure 12F As shown Figure 12C-12E The perspective view of the V-shaped container 1271 shown shows the OER electrode 1221 extending vertically along the crease (i.e., bend) of the container.

[0119] Figure 13Stackable architectures according to various embodiments are illustrated. In some embodiments, a single housing 1352 contains multiple batteries 1350, which are ion-separated from each other by electrically insulating partition walls. Each battery 1350 may be designed with an ORR electrode on top and OER electrodes around the edges (like a bed skirt), but each container / housing 1352 contains multiple batteries 1350. The internal batteries 1350 may be all ion-connected (permeable to electrolyte) or may be hydraulically / ion-separated. Housings 1352 may be stacked on top of each other to form a module 1300. Figure 13 The module 1300, which has 40 housings 1352, is shown.

[0120] Figure 14 The reverse-intake architecture according to various implementation schemes is shown. Figure 14 A "reverse-air intake design" is shown, in which the ORR electrode block 1430 can be an ORR electrode box filled with air. The anodes 1410 are clamped together, and the OER electrode 1420 separates the ORR electrode 1430 from the anodes 1410. The entire unit is filled with liquid electrolyte.

[0121] Figure 15 A reverse-inspiratory ORR electrode assembly 1500 according to various embodiments is shown. Assembly 1500 can be used as... Figure 14 ORR electrode block 1430. The shaded area is the ORR electrode area, while the unshaded area can be structural support. Air is supplied to the internal volume of the "box", and liquid electrolyte can surround the assembly 1500.

[0122] Figure 16 Another reverse-intake ORR electrode assembly according to various embodiments is shown. This assembly may include an anode 1610, an ORR electrode cartridge 1625, and an OER electrode 1620. The ORR electrode cartridge 1625 does not need to be completely sealed; that is, the bottom can be open. This has the advantage that if the ORR electrode leaks, the liquid electrolyte 140 can flow back into the integral electrolyte reservoir 1650. An air line can supply air to the ORR electrode cartridge 1625.

[0123] Naturally aspirated implementations may have several important limitations. With the ORR electrode vertical, the cell height is limited by the hydraulic pressure head on the ORR electrode (i.e., the electrode must also act as a structural element), preventing leakage to the external environment. Conversely, for a horizontal ORR configuration, the cell height is limited by the anode thickness, approximately 3 cm to 5 cm for 100 h and approximately 4 cm to 6 cm for 300 h. Therefore, achieving high system-level energy density (kWh / m³) is challenging. 2 or kW / m 2The core mechanical repeating units must be stacked multiple times, and the top space must be allowed to deliver gas to the battery.

[0124] Therefore, in some embodiments, it is advantageous to immerse the ORR electrode below the electrolyte level in the battery. In these embodiments, the three-phase boundary is created by forcibly supplying air (oxygen) to the ORR electrode located below the electrolyte level. This has several advantages. First, the ORR electrode is typically wetted, which reduces the risk of electrode drying and salt crusting. Second, leakage through the electrode can occur purely within the battery, without causing electrolyte leakage into the external environment. Third, the depth of the battery can be significantly greater (the height dimension of the main casing).

[0125] Figure 17 and Figure 18 Examples of an immersion electrode 1720 without a protruding oxygen bag structure according to various embodiments are shown. The immersion electrode 1720 can be completely immersed and placed vertically in a protruding electrode structure, thus maintaining a continuous "oxygen bag". As oxygen is depleted, it needs to be replenished by bubbling or constant pressure. The hydrophobic layer can be configured to withstand the pressure of gas escaping from the bag.

[0126] Figure 19A and Figure 19B Side and top views of another reverse-intake design according to various implementation schemes are shown respectively. Figure 19A and 19B The battery shown is Figure 7A and Figure 7B The battery pack shown is similar. Figure 19A and 19B In the battery pack shown, the curved (recessed) ORR sheet traps air beneath the electrode. The getter electrode 1720 can be supplied with air by a bubbler 1902 or other air source. One advantage of submerging the getter electrode 1720 equipped with an underwater bubbler is that any crust formation can be "washed away" by the electrolyte 140 during subsequent charging half-cycles.

[0127] In one embodiment, the air can be sealed within an air chamber, such that the air only contacts the solid surface. In another embodiment, the air forms bubbles such that at least one side of the bubble contacts the air electrode, while the other side forms a gas-liquid interface with the electrolyte. In either embodiment, the air volumes can be vertically stacked to allow the battery to be vertically sized.

[0128] In one embodiment, the electrode may have a high sealing wall and an unsealed bottom. Pressurized air is supplied to the internal volume and controlled by a pressure regulator at the outlet, an outlet located near the bottom of the volume, or otherwise. Any leakage through the ORR electrode can be contained by the bottom of the opening exposed to the electrolyte. Positive pressure within the volume helps prevent leakage through the electrode.

[0129] Figures 20A-23 Tubular ORR assemblies according to various embodiments are shown. In one embodiment, the electrodes may have, for example... Figure 20C The tubular shape 2130 is shown. The electrode can be made of, for example, Figure 20A The sheet-like electrode shown is made by spiral welding (e.g., Figure 20B and Figure 22A Self-sealing, edge welding (with a 2200 seal at the joint) Figure 22B or Figure 22D Self-sealing, using mounting body 2202 or outer casing ( Figure 22C (Sealed.) Tubular shape 2130 can be circular, oval, teardrop-shaped, or polygonal. For example... Figure 22E As shown, the electrode can be extruded into a pre-formed geometry and connected (e.g., by welding) to one or more solid current collectors 2212, [4]. The connection to the current collector can be only at the top of the tube (e.g., 2211 to 2212), or at both the top and bottom (e.g., 2213 to 2214). Figure 22E As shown in components 2215 and 2216, this method of connecting individual parts to each other allows the plane to be formed into a series of tubes. Additional sealant can be applied before or after connecting the electrode to the current collector or bus bars. This sealant can be a hot-melt sealant, introduced into the interior of the air electrode in solid form 2217, or applied to the current collector 2217a before connection and melted after or during connection to the current collector to coat the internal connection surface 2218. It can be horizontally fixed ( Figure 23 ) or vertically fixed ( Figure 21A , Figure 21B , Figure 21C The tube can be sealed at its ends to make it impermeable to liquid, or its ends can be placed outside the electrolyte so that the end seals do not necessarily have to be impermeable to liquid.

[0130] like Figure 21B and Figure 21CAs shown, in some embodiments, the cylindrical cell 2150 architecture can allow for various anode forms to complete an electrochemical cell with a powdered or sheet-like cathode 2152. The anode 2153 forms the center of the cylindrical cell 2150 and is positioned by a cylindrical "retainer" feature 2151 consisting of a semi-permeable separator and structural frame / positioning features. Powder or pellets can form the anode 2153. The cathode 2154 is a powder / granular material filled around the anode 2153. The cathode 2154 can also be a sheet rolled into a tube. Current is collected from the anode by sealing and compressing the electrical isolation cap of the cell 2150. Current is collected from the cathode through the outer cylinder 2155 of the cell 2150.

[0131] Figure 24 A bottom-opening reverse-intake ORR electrode design is shown according to various embodiments. Positive pressure can be applied to the intake side of the intake electrode, reducing the pressure difference across the electrode and eliminating the need to maintain pressure. The walls of the ORR electrode 2430 can be supported within a frame 2432, and air 2465 can flow through the center of the frame 2432 and the ORR electrode 2430. The bottom opening allows liquid electrolyte 140 to exit to the outlet.

[0132] In configurations requiring air delivery to air electrodes, active surface area is highly valuable. The power generation components, such as air electrodes, must be fully utilized to amortize their costs. To maximize the efficiency of these components, air delivery can be optimized by designing geometries and reactor layouts for high utilization. In this embodiment, cylindrical or other shaped tubes provide air passages within the housing and interfaces with the active material. The thickness of the active material and airflow are adjusted to optimize performance. By controlling the gas passages and airflow to maximize performance, the valuable surface area is made most effective.

[0133] Figure 25A Distillation column designs according to various implementation schemes are shown. Figure 25A This shows a stack of three stacked core ORR electrodes 2510, arranged in a stack 2500. Air / gas / oxygen can move from one layer to the next (upwards). Figure 25B As shown, each electrode layer 2510 may exhibit extension features 2515a or 2515b, such as ledges, lops, corners, or landing platforms, to capture bubbles 2514 and prevent them from rising to the next layer above. Figure 25B It is shown that the bubbles 2514 captured by this extension feature 2515a or 2515b can improve bubble collection in the bubble layer 2512 below the layer of ORR electrode 2510, thereby improving air utilization.

[0134] Figure 26AAlternative distillation column designs according to various embodiments are shown. The stack 2600 of ORR electrodes 2620 can be angled. Gas bubbles upward through electrolyte 140 to the stack 2600. Each ORR electrode 2620 can be extended by a baffle 2621. The baffle 2621 allows the bubble residence time to be sufficient for the gas to react on the electrode 2620; that is, without the baffle, the bubbles would bounce off.

[0135] like Figure 26B As shown, maintaining a uniform air sheath (or “thick layer of air”) 2612 beneath the submerged ORR electrode 2620 for a sufficiently long residence time to allow oxygen to react with the ORR electrode 2620 can be challenging. In some embodiments, the ORR electrode 2620 is flushed with electrolyte 140, purging gases to wash away hydroxide or carbonate crystals that may form on the ORR electrode 2620. In some embodiments, the ORR electrode 2620 may be mechanically fixed to a fulcrum 2650 located at the center of the ORR electrode 2620, allowing the ORR electrode 2620 to rock back and forth or tilt. The rocking motion of the ORR electrode 2620 can release gases upward and subsequently overflow electrolyte 140 to wash away salt crystals. The ORR rocking contacts and periodically flushes the ORR electrode 2620. In some embodiments, the rocking motion may allow some air bubbles to remain beneath the air electrode, thereby maintaining electrochemical function on the portion of the ORR electrode 2620 where the air bubbles are retained.

[0136] Figures 27-34 The configuration of additional stacked core ORR electrodes according to various implementation schemes is shown. Figure 27 A coaxial design for battery 2710 is shown. In some embodiments, the battery is configured as tubes arranged vertically together in an array. Figure 27 This is a top view of battery 2710. Figure 28 and Figure 29 This is a cross-sectional view of battery 2710. Figure 30 This is a view of an array of multiple 2710 batteries. Figure 31 Battery 2710 is shown. Figure 32 An array of multiple batteries 2710 is shown. Figure 33 An alternative configuration for battery 3310 is shown, and Figure 34An alternative array 3320 for battery 3310 is shown. Battery 2710 may include an immersed cylindrical ORR electrode core 2700 surrounded by a hexagonal tube filled with anode material 2702 (e.g., DRI beads). A porous anode current collector 2704 may surround the anode material 2702, and a mesh of OER electrodes 2712 may be outside the anode current collector 2704. The anode current collector can be multifunctional, for example, if placed through the center of an anode bed. It can provide structural support for the bed, to which the anode material can be mounted or pressed. It also helps to position the anode within the battery, separate adjacent batteries, or stack voltages. The battery stack is immersed in an electrolyte 140 pool, and air may be supplied via the ORR array by an immersed air bubbler 2705.

[0137] Figure 35A Another configuration of the stacked core ORR electrode is shown according to various implementation schemes. (e.g.) Figure 35A As shown, air and ORR electrodes 3520 and 2510 with different sealed volumes can be arranged together in electrolyte 140. Figure 35B As shown, in some embodiments, the thicknesses of the bubbles 3571, 3572, 3573, and 3574 below the ORR electrode 2510 can be different. For example, as Figure 35B As shown, the bubbles or layers beneath the ORR electrode 2510 can be increased from the smallest to the largest. The ORR electrode 2510 can be supported in a bracket 3580, allowing some air to escape from each support and for the bubbles to flow upwards to the next larger / higher bubble or layer. Increasing the bubble thickness can increase the residence time of oxygen under a particular ORR layer, thereby increasing the air utilization of that layer. Changing or increasing the bubble thickness can improve bubble flow. Increasing the bubble thickness as the vertical height in the stacked core increases can increase the overall air utilization in an implementation of the stacked core ORR electrode.

[0138] like Figure 35CAs shown, in some embodiments, the air 3582 flowing through the stacked core ORR electrode 2510 takes the form of a continuous air sleeve flowing through the ORR column, such that each air pocket trapped below the ORR electrode is connected in series with other air pockets. The continuous air channel can be formed by a support 381 supporting the ORR electrode 2510. The continuous air sleeve can reduce the impact of discontinuous bubble flow on the durability of the ORR electrode, including electrolyte splashing or salt crusting, especially on the air side of the ORR electrode. Reducing salt crusting can increase the effective electrochemical active area throughout the lifetime of the ORR electrode. In one embodiment, the continuous air sleeve is implemented by using a tube as a gas outlet for one air pocket and inserting the gas into the next air pocket, preventing bubble impact and electrolyte splashing. Enclosing the gas in a continuous sleeve also prevents the gas from escaping horizontally from the ORR electrode layer column.

[0139] Figure 36A Another configuration 3600 of a stacked core ORR electrode according to various embodiments is shown. The dashed line 3660 passing through component 3600 illustrates the movement of air from one layer to the next and the formation of an "air layer" on the underside of the electrode.

[0140] like Figure 36B As shown, in some embodiments, the configuration 3615 of the stacked core ORR electrodes can be encased in a porous spacer material 3616 with a pore size ranging from 1 μm to 1 cm. The porous spacer 3616 prevents bubbles from escaping horizontally from the column. Preventing horizontal bubble escape increases air utilization and prevents self-discharge of adjacent metal anodes due to contact between the anode and oxygen. Figure 36B An exemplary placement of the ORR layer 2510 and the current collector 3618 is also shown.

[0141] Figures 37-43The effects of applying varying degrees of air pressure to an air-jet electrode according to various embodiments are illustrated. Air jetting can improve the performance of dissolved oxygen saturation in an immersed ORR electrode. In various embodiments, oxygen can be introduced into the cell via bubbling, jetting, or other similar methods. Oxygen reduction reaction electrodes require an oxygen supply that can typically be provided by ambient air. The need for exposure to oxygen on one side and to a liquid electrolyte on the other presents challenges in sealing and removing residual air bubbles. A getter electrode can be immersed in a geometry that allows it to trap air bubbles. The bubbles provide oxygen and are replenished by the air supplied to the assembly. The assembly can be vertically repeated, allowing air to be continuously delivered from lower to higher levels. Bubbles may easily bounce off or fail to adhere to the immersed air electrode, meaning there is insufficient time for a reaction to occur before they leave. In one embodiment, a mechanical lip or baffle can be used to allow bubbles to remain on the air electrode for a longer period. If membrane ORR electrodes are stacked alternately with the hydrophobic side down and air is supplied via a volumetric containment, the air will flow across the hydrophobic side and form a pocket, while leaving the electrolyte on the hydrophilic side. The presence of pores in the membrane layer further enhances this flow through the reactor. In one embodiment, the air electrode and / or support housing can be configured to form a spiral (e.g., an augur, helical, or spiral staircase shape). Such shapes will allow for upward airflow or continuous transfer of bubbles forming on the catalyst layer of the ORR electrode. Figure 37 and Figure 38 The top and bottom views of the sample holder used for performing the jet ORR electrode experiment are shown. Figure 39 The relationship between the bubble flow and the angle of the sample is shown in an experiment conducted using a sample holder. Figures 40-43 It is a graph showing the results of those experiments.

[0142] Figure 44 A design for a spiral-shaped ORR electrode 4420 according to various embodiments is shown. The spiral-shaped ORR electrode 4420 and / or the support housing 470 can be configured such that it forms a spiral (e.g., a spiral, helical, or spiral staircase shape). Such shapes can allow for upward airflow or continuous transfer of bubbles forming on the catalyst layer of the spiral-shaped ORR electrode.

[0143] Oxygen-reduction reaction (ORR) electrodes must be supplied with oxygen when exposed to the electrolyte. Positioning the solid-gas-liquid three-phase boundary on the ORR electrode is complex because the ORR electrode cannot withstand large pressure differentials, etc. Furthermore, to allow for vertical cell development, it is advantageous to position this three-phase point below the upper surface of the free electrolyte. Inverted cups trap air pockets that supply oxygen to the hydrophobic underside of the two-dimensional (2D) or sheet-like ORR electrode. The top surface of this electrode is wetted by the surrounding electrolyte. Gas is supplied at a flow rate sufficient to replenish the oxygen consumed by the ORR at the electrode. These cups can be embodied in circular geometries, as previously disclosed. However, these circular embodiments result in annular electrode arrangements, leading to altered current densities, dead zones between cells, or geometric invariance. “Stretching” the ORR cups into an extended “tray” and stacking these trays in vertical, thick “plates” allows for a linear cell geometry. The sides of the ORR “plate” are the anode “plates,” the sides of the anode “plates” are the OER “plates,” and so on. These planar geometries allow for constant current density, high volumetric efficiency, significantly reduced number of parts, and fewer assembly steps.

[0144] In another implementation, a highly automated, angle-controllable air jet electrode array can be used to increase the residence time of bubbles on the air electrodes.

[0145] Figures 45-47B Various configurations of the linear ORR electrode 4620 according to various embodiments are shown. Figure 45 The arrangement of ORR electrode block 4502, anode material block 4503, and OER electrode block 4504 according to an embodiment is shown. ORR electrode block 4502 may comprise a linear stack of ORR electrodes, as shown in Figure 46- Figure 47B ORR electrode 4620. Figure 46A A side view is shown. Figure 46B An end view is shown. Figure 47A A side view of the airflow is shown. Figure 47B A top view is shown. The ORR electrode 4620 may be a parallel plate supported in a frame 4621, which has an air inlet 4622 on one side and an air outlet 4623 on the other side. Air can flow through the ORR electrode 4620 and move upward through the electrolyte 140.

[0146] Figures 48-49 Diagrams and snorkel cup designs based on various implementation schemes are shown.

[0147] Figure 50A cross-sectional side view of a test tube design according to various embodiments is shown. The immersed oxygen reduction electrode 5001 (e.g., a hydrophilic porous electrode) providing the air supply 5002 would require significant pressurization of the supplied air to overcome fluid pressure. The geometry of the immersed air channel can be controlled to provide a channel for a mixed air / electrolyte to the ambient atmosphere. This mixed-phase channel reduces the pressure required to supply air to the immersed electrode.

[0148] Getter electrodes have limited tolerance to maintaining liquid pressure, for example, in vertical electrode configurations where the getter electrode acts as a wall maintaining the hydrostatic pressure of the electrolyte. In one embodiment, the electrolyte is held together with a spacer, which may be nanoporous. The electrolyte may begin to leak through the spacer and into a very narrow gap between the spacer and the getter electrode. There may be an outlet at the bottom of the electrode for the electrolyte to flow out of the gap and into the next cell. This slow flow generates less pressure on the getter electrode compared to the hydrostatic pressure of the electrolyte. In another embodiment, the spacer is placed directly on the electrolyte side of the getter electrode to reduce the pressure difference across the getter electrode through surface tension or other pressure-reducing mechanisms. The thickness or porosity of the spacer may vary with depth; for example, the spacer thickens at the bottom where the hydrostatic pressure on the getter electrode “wall” is greatest. In yet another embodiment, the getter electrode has segmented pressure relief points that allow electrolyte flow and leakage, resetting the hydrostatic pressure of the electrolyte to atmospheric pressure. In another embodiment, the getter electrode is self-healing, such as a cork-like material, where pinholes or leaks re-seal themselves when wetted by a liquid electrolyte. In yet another embodiment, an electrolyte additive is used to seal pinholes or leaks, such as a small plate.

[0149] In various embodiments, the battery pack (e.g., battery pack 100) may include three electrodes: an anode (e.g., anode 110) and dual cathodes (e.g., cathode 120 consisting of two components, such as a first cathode and a second cathode). The electrodes may have a limited lifespan and may be mechanically replaceable. For example, the anode may be seasonally replaceable. The first cathode may be divided into two parts, with a hydrophilic surface and a hydrophobic surface. For example, the hydrophobic surface may be a polytetrafluoroethylene (PTFE) (e.g., Teflon®) hydrophobic surface. For example, the second part may be a microporous layer (MPL) of PTFE and high surface area carbon, while the first part may be carbon fiber partially coated with PTFE. As another example, the second part may be an MPL of PTFE and carbon black, and the first part may be approximately 33% by weight of PTFE. As a further example, the second part may be an MPL of 23% by weight of PTFE and 77% by weight of carbon black, and the first part may be a low-load MPL. The anode can be an iron (Fe) electrode or an iron alloy (Fe-alloy) electrode (e.g., FeAl, FeZn, FeMg, etc.). The second cathode can have a hydrophilic surface. The second cathode can have a metal substrate coated with nickel (Ni), such as carbon (C), titanium (Ti), steel, etc. An electrolyte (e.g., electrolyte 140) can be disposed between the three electrodes. The electrolyte can permeate into one or more of the three electrodes.

[0150] In some embodiments using alkaline (high pH) electrolytes, exposure to and dissolution of carbon dioxide (CO2) in the volume of liquid electrolyte 140 leads to changes in the pH of the electrolyte, changes in the electrolyte ionic conductivity, and precipitation of carbonate solids in the electrolyte, which can clog the pores in the air electrode 120 and / or anode 110. To address the presence of carbon dioxide and / or carbonate ions (CO3) in the volume of liquid electrolyte 140... 2-The accumulation, washing, or filtration of the liquid electrolyte 140 can be used to process the volume of the liquid electrolyte 140 and remove carbon dioxide and / or carbonates. As an example, a filter unit can be used to wash or filter carbon dioxide and / or carbonates from the volume of the liquid electrolyte 140. As an example, the filter unit may include a pump that circulates the electrolyte through the filter to remove carbon dioxide and / or carbonates from the volume of the liquid electrolyte 140. Carbon dioxide can be vented into the air in the gas headspace 105. Alternatively, carbon dioxide and / or carbonates can be captured in the filter unit, and the filter unit can be replaced periodically. For example, the filter unit may contain chemical reagents or scrubbers that react strongly with carbon dioxide and / or carbonates to bind and capture unwanted substances. For example, a gas phase filter may use sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), magnesium hydroxide (Mg(OH)2), barium hydroxide (Ba(OH)2), or mixtures of these reagents to chemically capture carbon dioxide before it reaches the battery. Alternatively, the filter unit can flow through an electrolyte containing dissolved carbon dioxide and / or carbonates, exposing the electrolyte to a reaction medium that binds to and / or reacts with carbonate ions to remove them from the solution. For example, if the electrolyte is primarily potassium hydroxide, the filter can contain solid calcium hydroxide. Calcium carbonate is far less soluble than potassium carbonate, so the dissolved carbonate reacts with the calcium hydroxide to form calcium carbonate, which precipitates from the electrolyte and accumulates in the filter unit. The filter unit can be periodically replaced, updated, or refurbished to restore its functionality. The filter unit can operate at various intervals, such as intervals matched to the diffusion rate of carbon dioxide in the battery, to filter carbon dioxide and / or carbonates from the volume of liquid electrolyte 140. This maintains a sufficiently low level of carbon dioxide and / or carbonates in the volume of liquid electrolyte 140 to prevent or mitigate changes in pH, electrolyte ionic conductivity, and / or precipitation of solid carbonates in the electrolyte.

[0151] In one embodiment, a CO2 scrubbing reactor is created in which air is pumped through an electrolyte bath containing one or more concentrated alkali metal hydroxide salts (i.e., NaOH). In this specific embodiment, the reactor is designed such that the total pressure through the reactor is low, but the gas residence time is increased by creating a long, winding channel with a positive vertical slope. Baffles, sidewalls, ridges, or the like can be added to improve convective mixing in the reactor. This allows for minimal energy loss while maximizing the removal of CO2 from the air.

[0152] In some implementations, the accumulation of carbon dioxide and / or carbonate ions (CO3-) in the liquid electrolyte in any battery pack design herein is mitigated or prevented by using a sealed or partially sealed enclosure. 2- This is to prevent or limit the entry of gaseous CO2 from the ambient atmosphere into the liquid electrolyte. For example, the battery pack described herein may have enclosures in which ports, vents, or one-way valves allow gases generated within the enclosure to escape but limit the exposure of the enclosure's interior to atmospheric CO2. In some embodiments, the one-way valve is a liquid-containing airlock, bubbler, or trap, designed similarly to those commonly used in brewing beer and wine.

[0153] Due to the chemical reaction at the anode, the iron anode material generates bubbles. These bubbles can interfere with other components of the electrochemical cell. In one embodiment, a gasket or fixing device is used to position the bubble-generating electrode above other components that may be sensitive to bubbles. The bubble channel then does not come into contact with the bubble-sensitive components because the bubbles move upward in the liquid. Typically, this method positions the component that generates upward-moving products (e.g., bubbles in the liquid) above components that are sensitive to those products. Similarly, the component that generates downward-moving products (e.g., precipitates) can be located below other components that are sensitive to those products.

[0154] Charged metal electrodes in an electrolyte can self-discharge. For example, a reduced iron (Fe) electrode in an alkaline solution will self-discharge according to the spontaneous reaction Fe + 2H₂O ⇆ Fe(OH)₂ + H₂. In open metal-air battery packs (i.e., unsealed battery packs), such as iron-air (Fe-air) battery packs, the removal of the metal electrode from the electrolyte can be provided to prevent self-discharge of the metal electrode. In various embodiments, a pump can pump liquid electrolyte into and out of the battery pack container such that the metal electrode is immersed in the liquid electrolyte when the liquid electrolyte is pumped into the container, and is removed from the liquid electrolyte when the liquid electrolyte is pumped out of the container. In various embodiments, an inflatable bladder can be inflated and deflated to move the liquid electrolyte such that the metal electrode is immersed in the liquid electrolyte when the bladder is inflated, and is removed from the liquid electrolyte when the bladder is deflated. In various embodiments, one or more lifting systems can raise and lower the metal electrode from the liquid electrolyte. Removing the metal electrode from the electrolyte prevents self-discharge of the metal electrode.

[0155] Figure 51A cross-sectional side view showing the variation of the angle of repose of the ORR electrode 5100 according to various embodiments is shown. In some system configurations with getter electrodes, it is useful to place the getter electrode at the gas-liquid boundary. However, the gas-liquid boundary can differ in angle and height between cells. In one embodiment, the ORR electrode 5100 may have a corrugated surface to accommodate the differences in angle and height between cells. In another embodiment, the air electrode is a volumetric sponge-type electrode with sufficient thickness to accommodate the differences in angle and height between cells.

[0156] Two problems arising from stagnant electrolytes are bubble formation and pH gradient generation during charging and discharging. Bubbles may fail to escape from the electrolyte and may adhere to the electrode, leading to performance degradation. pH gradients in the electrolyte can also cause electrode performance degradation or corrosion. One solution to the bubble and pH gradient problems might be to use a low flow rate (e.g., less than 1 mL / min / cm). 2 Circulating electrolyte. This electrolyte flow allows bubbles to escape more easily, providing convenient and even automated bubble management. Furthermore, the flowing electrolyte can provide pH control, thus preventing the formation of gradients.

[0157] As described above, in various embodiments, the battery pack (e.g., battery pack 100) may include three electrodes: an anode (e.g., anode 110) and dual cathodes (e.g., cathode 120 consisting of two components such as a first cathode and a second cathode). In recharge operation mode, the electrolyte level (e.g., electrolyte 140) may be lowered to expose the second cathode to air. The electrolyte level in the battery pack may be controlled by pumps, valves, and / or other systems to change the electrolyte level to submerge or not submerge the second cathode, respectively, in discharge and recharge modes. In recharge mode, a dry oxidation reaction (HOR) may occur at the second cathode, while a two-phase oxygen evolution reaction (OER) may occur at the first cathode. When the anode is an Fe anode, hydrogen (H2) bubbles may be generated by the anode in an additional process in recharge mode. The hydrogen (H2) bubbles may be oxidized at the second cathode (i.e., electrons are recaptured). In recharge mode, the two cathodes may have different positive potentials relative to the anode, for example, 0.1V and 1.5V respectively, while the anode may be at -0.5V. This allows the second cathode to be kept at a more favorable potential of 0.1V, as it oxidizes the hydrogen (H2) bubbles generated by the anode.

[0158] In low-cost energy storage systems, it is advantageous to use current collector metals with high conductivity per unit cost, such as copper. However, some of these low-cost current collectors (such as copper) are unstable in alkaline aqueous electrolytes. To maintain separation between the current collector and the electrolyte, getter electrodes can have a structure that draws the electrolyte into it to promote the necessary three-phase boundary distribution while preventing the electrolyte from contacting the current collector.

[0159] Current collectors are among the most expensive components in an architecture, even when using low-cost metals such as stainless steel. Leveraging the spherical shape and high conductivity of DRI pellets, a cost-effective tapered current collector strategy can be applied to DRI bead-based anodes. As shown in the figure, the "active" current collector (or current collector coating) at the bottom of the cone occupies a small portion of the tapered bead enclosure; the gravity of the self-aligning DRI beads near the "conductive wall" acts as a "compressive force," ensuring good electrical contact between the DRI beads and the current collector. Optimal current collection in terms of resistance and cost can be achieved by optimizing the current collector thickness, current collector height, cone angle, and the size distribution of the DRI beads.

[0160] Electrochemical energy storage systems require electrode switching. Switching between electrodes necessitates some form of switching mechanism. While this can be accomplished electronically, such electronics must be able to withstand harsh chemical environments, remain reliable throughout the system's entire lifespan, and can be very expensive. Mechanical switching of electronic pathways may be a more robust, reliable, and chemically resistant solution. Mechanical contact switching, such as relays or light switches, can be used when the battery is ready to switch between charging and discharging modes. These switches may require flexible electronic connections or conductors, but this is standard practice in other fields.

[0161] The magnetism of DRI can be used to assemble anode beds. This unique property of Fe increases the design space for electrodes and architecture. For example, permanent magnets can be used as part of the current collector (above or below it) to provide additional pressure on the pellet bed. Magnets can be used to align the pellets, allowing them to be aligned and a string of pellets to be produced.

[0162] In some implementations, the anode can be moved between cathode regions. For example, as... Figure 52As shown, the anode 110 (e.g., a DRI pellet bed) can be moved from a first position to a second position within the electrolyte 140 inside the housing 170. One position may be below the first cathode 5230, and the second position may be below the second cathode 5210. For example, the first cathode 5230 may be an OER electrode and the second cathode 5210 may be an ORR electrode. The housing 170 may include an opening at the location of the ORR electrode 5210. Depending on the operating mode of the battery pack, the anode 110 can be moved back and forth to be positioned below the appropriate cathode type 5230, 5210.

[0163] Alkaline iron electrode battery packs typically operate best when used with an electrolyte and / or certain additives in the battery. For example, sulfur helps depassivate the iron electrode, but it is consumed by the battery. Sulfur consumption leads to a gradual decrease in capacity after many cycles. Therefore, a delivery system is needed to replenish the sulfur supply to maintain battery pack performance. One implementation of such a system could be a pump that delivers sulfur-containing liquid to the battery pack cells. Another implementation could be a dry hopper that delivers polysulfide salts to closed or open battery pack cells.

[0164] Electrolyte additives can have a range of solubilities, and some may have the most beneficial effects when tightly mixed with a solid electrode. In some embodiments, the electrode may be pellet-shaped or composed of multiple pellet-shaped subunits. One method of delivering the additives is to manufacture pellets comprising the additives or pellets consisting entirely of the additives. Such additives may be FeS or FeS2. Other pellets may consist primarily of other active materials. Different types of pellets can be mixed to produce hybrid electrodes.

[0165] Migration of bubbles, electrolyte components, or solids from one part of an energy storage system to another via the electrolyte may be undesirable. Such migration can be prevented using low-cost porous separators with sufficient chemical and mechanical compatibility. In one embodiment, ultra-low-cost separators, such as polybenzimidazole separators and polypropylene separators (e.g., Celgard 3501), can be used between the anode and cathode of the energy storage system. Both separators exhibit sufficient chemical and mechanical compatibility with the target system.

[0166] Metal-air battery systems can be designed to capture and store oxygen generated during charging. This oxygen can then be directed to the ORR electrode during discharge. Collecting and reusing oxygen improves overall system efficiency and also enhances the rate capability of the ORR electrode. The oxygen can be stored in a canister, headspace, or balloon. This system-level approach can be applied to zinc-air, iron-air, aluminum-air, or lithium-air battery systems.

[0167] ORR electrode efficiency increases with increasing oxygen concentration. Therefore, it is preferable to collect the oxygen generated during OER for later use during ORR. Oxygen storage can be achieved through a combination of inflatable reservoirs, gas compression, gas adsorption, and oxygen liquefaction, followed by delivery of oxygen to the ORR electrode during discharge.

[0168] Figure 53A and Figure 53B Cross-sectional side and top views of a battery pack according to various embodiments are shown. The battery pack may include an ORR electrode 5302 located at the liquid / gas interface, where the electrolyte 140 encounters air in the gas headspace 105. The ORR electrode 5302 may float on the electrolyte 140 (i.e., passively self-positioned at the interface) or be rigidly supported at the liquid / gas interface. The battery pack may include an optional spacer 5304 to prevent air from reaching the anode 110 (e.g., a metal electrode).

[0169] Figure 54 A cross-sectional side view of an getter electrode (e.g., cathode 120) according to various embodiments is shown. In a "standard" configuration, when cathode 120 is an getter electrode (e.g., an ORR electrode), the cathode may remain on the surface of electrolyte 140. Figure 55 In the illustrated "reverse" getter configuration, cathode 120 can be submerged in electrolyte 140 below its liquid level. In this "reverse" configuration, cathode 120 can be supported by a sealed container 5502. When cathode 120 is an getter electrode (e.g., an ORR electrode), air can be pushed into / through the volume of the sealed container 5502 to supply air to cathode 120. Cathode 120 can be immersed in electrolyte 140, but the air and the frame of the sealed container 5502 ensure that cathode 120 is at the three-phase boundary. In various embodiments, to ensure a stable three-phase boundary for the ORR reaction, air must be delivered to this surface in an efficient and cost-effective manner.

[0170] Figure 56 A cross-sectional side view of a jet-air electrode (another example of a “reverse” configuration) according to various embodiments is shown. By pumping air from a bubbler 5602 into the electrolyte 140, the jet-air configuration allows the cathode 120 (e.g., a getter electrode, such as an ORR electrode) to be positioned at the three-phase boundary. A frame 5603 supporting the cathode 120 (e.g., a baffled frame) can be immersed in the electrolyte 140. However, bubbles from below the cathode 120 in the bubbler 5602 can create a localized three-phase boundary. Even if the ORR electrode is below the electrolyte level 140, bubbles will form a reservoir behind the ORR electrode. Figure 57 Various implementation schemes are shown. Figure 56A cross-sectional side view of the stacked jet air electrode assembly. Figure 58 Various implementation schemes are shown. Figure 56 A cross-sectional side view of the stacked and interlaced jet air electrode assemblies. Figure 57 In this configuration, the injection components are stacked directly on top of each other, with air channels in between to provide pathways for bubble leakage. Figure 58 In this process, the jetting components are offset from each other (i.e., staggered) and the bubbles move in the gaps between the components.

[0171] In any unsealed ORR architecture, for example Figure 56 , Figure 57 and Figure 58 In the architecture shown, the pressure of the supplied air must be at least ρ. g h, where h extends from the top of electrolyte 140 to the air inlet surface of bubbler 5602, regardless of the airflow velocity from the electrolyte. In contrast, by sealing the surface at the three-phase boundary, for example, at... Figure 55 In an immersion configuration, the pressure required to supply air and achieve the electrochemical reaction can be much lower than at an unsealed three-phase boundary (e.g., Figure 56 , Figure 57 and Figure 58 (As shown) the required pressure. In a vertically sealed ORR configuration, for example... Figure 55 In this configuration, this reduced air pressure (e.g., low-pressure (LP) air demand) can reduce the auxiliary power load required for pumping air, especially with unsealed three-phase boundaries (e.g., Figure 56 , Figure 57 and Figure 58 (As shown) The required higher pressure is much lower than the required pressure.

[0172] Reverse-intake electrodes can be formed in many different shapes, such as Figures 59-62 As shown. Figure 59 A perspective view of a rectangular tubular ORR electrode design according to various embodiments is shown. The rectangular design may provide four outer surfaces and four inner surfaces of the tube. In some embodiments, all surfaces may be ORR electrodes, or a subset of the surfaces may be ORR electrodes. Figure 60 Another circular tubular design is shown. The tubular ORR electrode can be a single extended tube, or it can be a spiral tube made of a wrapped sheet of ORR material. For example... Figure 61 As shown, the tube array can be arranged in a single container supporting the electrolyte 140 and the anode 110. Air can pass through the tubes. In various embodiments, the number and arrangement of the tubes can vary. Figure 62The diagram illustrates that in various embodiments, the tube can be formed from a pinched sheet of ORR electrode material. The sheet itself can be bent and sealed at the top.

[0173] Bubbles on submerged horizontal electrodes tend to exhibit turbulent slug flow. Various embodiments can provide ramps and orifice arrays for airflow regulation of the submerged electrodes. In various embodiments, ramps and orifice arrays can minimize the energy barrier for bubbles escaping through the orifices in the electrode retainer cup, promoting continuous flow patterns and separating small bubbles from the air bag for interlayer transport. Gas and bubble flow management in horizontally oriented ORR electrodes is difficult. Various embodiments provide horizontally stacked ORR electrodes that allow airflow through each individual layer for easier air control.

[0174] One of the major limitations in producing long-duration bifunctional air electrodes is that the carbon substrate, which is typically used as a catalyst support for oxygen reduction reaction (ORR) cathodes, is unstable at the potentials present in oxygen evolution reaction (OER) cathodes. For long-duration electrodes to be fabricated, the two cathodes should be electronically separable.

[0175] Various implementations can provide mechanical mechanisms relying on a rigid OER electrode and a flexible ORR electrode, wherein the flexible ORR electrode is configured to allow electronic separation of the OER electrode and the ORR electrode, such as... Figure 63A and Figure 63B As shown. In some embodiments, the flexible ORR cathode 631 can be placed within the rigid metal OER cathode 630. The ORR cathode 631 forms its own air pocket, allowing air to be supplied within it. In this way, the ORR cathode 631 forms an ORR cavity. When air is supplied to the ORR cavity, the ORR cathode 631 expands against the rigid metal OER cathode 630, electrically connecting it to the load, such as... Figure 63A As shown. When the airflow is shut off, the hydrodynamics of the electrolyte pushes the ORR cathode 631 away from the rigid metal OER cathode 630, thereby keeping the ORR cathode 631 and the rigid metal OER cathode 630 separated.

[0176] When the ORR electrode overflows, the loss of the three-phase boundary signifies ORR electrode failure. Various implementations may include providing a drain valve at the bottom of the ORR chamber to allow the removal of excess electrolyte. Removing excess electrolyte via the drain valve prevents ORR electrode failure due to the loss of the three-phase boundary.

[0177] An ORR electrode requires an electrolyte on one side and gaseous oxygen, which can be in the form of air, on the other. In deeper electrolyte volumes, the electrolyte pressure at the bottom of the electrode can differ significantly from the pressure at the top. For this pressure gradient, a single electrode sheet may not be optimal.

[0178] In various implementations, the vertical dimension of the continuous electrolyte depth can be divided into smaller segments, each with its own ORR electrode. Figure 64 An embodiment of this stacked ORR electrode configuration 6401, 6404, 6405 is shown. Each of electrodes 6401, 6404, 6405 can be an ORR electrode adjusted to a different operating pressure. Each of electrodes 6401, 6404, 6405 can be customized for the operating pressure of each electrode 6401, 6404, 6405 in electrolyte 140. Electrodes 6401, 6404, 6405 can be horizontal strips of ORR sheet electrodes supported on a vertical plane by current collector 6402, such that electrodes 6401, 6404, 6405 are stacked on top of each other to minimize vertical pressure variations on each electrode 6401, 6404, 6405, and each height electrode can be optimized for its specified height. Current collection and sealing can accommodate multiple strips. Current collector 6402 may include current collector tab 6403. The pressure variations on electrodes 6401, 6404, and 6405 can be identical. Although Figure 63 shows three stacked electrodes 6401, 6404, and 6405, more or fewer stacked electrodes can be used in various embodiments, with each electrode adjusted according to its respective depth to withstand pressure in the electrolyte 140.

[0179] In iron-air batteries, a horizontal position of the ORR electrode can be advantageous. However, air must be confined below the ORR electrode for the ORR reaction to occur. Figure 65 An ORR electrode 6500 including a porous separator 6501 is shown according to various embodiments. Various embodiments may include a porous separator 6501 supported beneath the ORR electrode 6500, which allows air to enter but traps it until a certain pressure is reached (i.e., higher than the pressure at which air is forced through the porous separator 6501). The ORR electrode 6500 with the porous separator 6501 design is pressure-resistant because air escapes directly through the separator 6501.

[0180] Systems based on horizontal cathodes are sensitive to the horizontal height of the ORR electrode. If the electrode is not supported so that the ORR electrode plane is level with the electrolyte, the area of ​​the active region exposed to air will be reduced. For example, Figure 66AA horizontal ORR electrode 6600 is shown that is not at the same level as the electrolyte 140, which means that air is not completely confined under all portions of the ORR electrode 6600. Instead, because the immersed ORR electrode 6600 is not horizontal, air is only confined under a portion 6602 of the ORR electrode 6600, and no air is exposed to the other portion 6601. Therefore, the portion 6602 exposed to air can be the active portion, while the other portion 6601 is inert. Keeping the ORR electrode 6600 in a horizontal position ensures that the entire electrode 6600 (i.e., portions 6601 and 6602) is exposed to air and is the active portion. Various embodiments can provide horizontal assemblies for the ORR electrode, such as a stack of horizontal ORR electrodes 6611. Reducing the overall width of the ORR electrode can improve this angular tolerance.

[0181] Figures 66B-66E Exemplary passive and active level control systems according to various implementation schemes are shown. Figure 66B The ORR electrode support system as a passive suspension control system is shown. Figure 66C The ORR electrode support system as an active actuation control system is shown. Figure 66D The ORR electrode support system as a passive buoyancy control system is shown. Figure 66E The ORR electrode support system as a passive rolling control system is shown.

[0182] exist Figure 66B In the suspension control system, a housing 6610 supporting the stack of electrolyte 140 and horizontal ORR electrodes 6111 can be coupled to a support arm 6613, which is connected to a hinge 6612 suspended on a support rod 6614. The support rod 6614 can suspend the support arm 6613, the hinge 6612, and the housing 6610, which freely supports the stack of electrolyte 140 and horizontal ORR electrodes 6111 in space. The hinge 6612 can be configured to provide independent movement of the support arm 6613 relative to the support rod 6614, such that as the entire system to which the support rod 6614 is attached moves (e.g., not on a horizontal plane), the support arm 6613 and the housing 6610 supporting the stack of electrolyte 140 and horizontal ORR electrodes 6111 remain horizontal due to gravity above them.

[0183] exist Figure 66CIn the active actuation control system, the housing 6610 supporting the stack of electrolyte 140 and horizontal ORR electrode 6111 can be arranged on a series of actuators 6615, 6616 (e.g., lifters). Actuators 6615 and 6616 can be independently controlled to raise and / or lower the angle of housing 6610 so that housing 6610 remains horizontal.

[0184] exist Figure 66D In the passive buoyancy control system, the housing 6610 supporting the electrolyte 140 and the stack of horizontal ORR electrodes 6111 can move freely, but the stack of horizontal ORR electrodes 6111 can be supported by an arm 6621 connected to a float 6620 (e.g., a hollow plastic float, a foam float, etc.). Even if the housing 6610 can move, the float 6620 can float on the surface of the electrolyte 140 and keep the stack of horizontal ORR electrodes 6111 in a horizontal position.

[0185] exist Figure 66E In the passive rolling control system, the bottom of the housing 6630 supporting the stack of electrolyte 140 and horizontal ORR electrodes 6111 is flexible. The housing 6630 is free to move, but the stack of horizontal ORR electrodes 6111 can be supported by an arm 6632 connected to a wheel (or roller) 6631, which moves freely along the curved bottom of the housing 6630. When the housing 6630 moves, the wheel 6631 can use gravity to push the stack of horizontal ORR electrodes 6111 to the lowest point of the curved bottom of the housing 6630, thereby maintaining the stack of horizontal ORR electrodes 6111 horizontally.

[0186] The need to supply air to the ORR electrode can lead to excessive spacing between the cathode and anode electrodes, potentially increasing the ionic resistance between the ORR and anode electrodes. Various embodiments can simultaneously maximize container volume and reduce the anode-to-ORR electrode spacing by spacing the electrode assemblies at an angle rather than perpendicularly. Positioning the electrodes at an angle (i.e., non-perpendicularly) allows for either continuously connected anode beds or discontinuous anodes.

[0187] Figure 67A A vertically aligned electrode assembly is shown, comprising a vertical anode 6704 located outside a cathode housing 6703 supporting an ORR electrode 6702. The spacing between the surfaces of the ORR electrode 6702 and the anode 6704 can be relatively large.

[0188] Figure 67B and Figure 67C Interdigitated electrode assemblies of various implementation schemes are shown. Figure 67BA discontinuous configuration is shown, in which the anode 6704 is arranged between the cathode housings 6703, such that the spacing between the surface of the ORR electrode 6702 and the surface of the anode 6704 can be relatively small. Figure 67C A continuous configuration is shown, wherein the anode 6704 is angled and includes angled protrusions extending toward the cathode housing 6703. The cathode housing 6703 is angled between the anodes 6704, such that the spacing between the surfaces of the ORR electrode 6702 and the anodes 6704 can be relatively small.

[0189] Figure 68 An embodiment of a dual ORR and OER electrode configuration is shown, wherein the OER electrode 6803 is bent to create a pouch volume for the ORR electrode 6804. Figure 68 This configuration allows for a more direct ion channel from the anode 6802 to the cathode. Furthermore, Figure 68 This configuration can provide a more defined, slightly deeper gas volume that is less sensitive to angle. For example... Figure 68 As shown, when the ORR electrode 6804 extends from the OER electrode 6803, the OER electrode 6803 can be folded longitudinally to create a triangular cross-section. This triangular cross-section can be configured such that the area below the triangle is dedicated to air volume.

[0190] Various implementations may include battery pack configurations in which unsealed bubbles may be present beneath the ORR electrode. In such configurations, controlling the flow and pathway of the bubbles beneath the ORR electrode may be important to provide sufficient flow and prevent the bubbles from contacting other electrodes in channels outside the battery pack reaction vessel (e.g., reactor). Various implementation methods may be used to control the bubble flow / pathway, including outlet orifices in the ORR electrode, ramps, combinations of ramps and outlet orifices, multiple outlet orifices, different orifice sizes, nozzle-shaped orifices, localized surface roughness features, check valve outlets, flap valve outlets, buoyancy control valves, sponge / mesh outlets, and / or groove / non-circular geometry outlets. Figures 69A-69N Exemplary bubble control methods according to various implementation schemes are shown. Figure 69A An ORR electrode 6902 is shown, which is configured such that an outlet hole 6901a is present in the ORR electrode 6902 to allow a bubble 6903 to escape through the ORR electrode 6902. Figure 69A Can be used for discussion Figures 69A-69N The baseline configuration for the other configurations shown. Figure 69B An ORR electrode 6904 is shown, which is configured such that a plurality of outlet holes 6901b are present in the ORR electrode 6904 to allow bubbles to escape through the ORR electrode 6904. Figure 69CAn ORR electrode 6905 is shown, which is configured such that a relatively large outlet orifice 6901c exists in the ORR electrode 6905 (e.g., with...). Figure 69A Compared to the smaller pore 6901a in the ORR electrode 6905, this allows bubbles to escape through the ORR electrode 6905. Figure 69D An ORR electrode 6906 is shown, which is configured such that there are local surface roughness features at the edge of the outlet hole 6901d present in the ORR electrode 6906 to allow bubbles to escape through the ORR electrode 6906. Figure 69E An ORR electrode 6907 is shown, which is configured such that a check valve outlet 6901e is present in the ORR electrode 6907 to allow air bubbles to escape through the ORR electrode 6907. Figure 69F An ORR electrode 6908 is shown, which is configured such that a valve outlet 6901f is present in the ORR electrode 6908 to allow bubbles to escape through the ORR electrode 6908. Figure 69G An ORR electrode 6909 is shown, which is configured such that a sponge / mesh outlet 6901g is present in the ORR electrode 6909 to allow air bubbles to escape through the ORR electrode 6909. Figure 69H An ORR electrode 6910 is shown, which is configured such that a ramp outlet 6901h is present in the ORR electrode 6910 to allow bubbles to escape through the ORR electrode 6910. Figure 69I An ORR electrode 6911 is shown, which is configured such that the ORR electrode 6911 has a perforated ramp outlet 6901i in the ramp portion to allow bubbles to escape through the ORR electrode 6911. Figure 69J This is a top view of ORR electrode 6912, which is configured such that an outlet 6901j with a groove / non-circular geometry exists in ORR electrode 6912 to allow bubbles to escape through ORR electrode 6912. Figures 69K-69N This shows combinations of the features listed above and supplements to the features listed above. Figure 69K As shown Figure 69H The shown combination of the ramp outlet 6901k and the nozzle-shaped outlet orifice. Figure 69L As shown Figure 69H The ramp exit 6901l shown has the following characteristics: Figure 69B The multiple outlet holes 6902l shown can be designed with diameters that provide bubble release at the required pressure. Figure 69M The placement of the outlet port 6902M on the stepped feature 6901M is shown, such that the air bag is released only when it exceeds the step. Figure 69N As shown Figure 69M The stepped feature 6901N shown is similar to... Figure 69E The combination of the buoyancy control valve 6902N shown.

[0191] During operation, the rapid introduction of a gas with a higher O2 content at a given layer in the core design of the stack can cause discontinuous current responses in the ORR due to bubbles passing vertically through the ORR layer, resulting in current or voltage spikes. In some embodiments, the power output from the reactor can be smoothed by passing the electrical power through a rectifier, which can reduce the intensity of power spikes from the reactor. In such embodiments, the surrounding electrical system can increase bubble tolerance, thereby creating inconsistent electrochemical reaction rates within the core ORR electrode of the stack.

[0192] During operation, the OER electrode releases oxygen from the surfaces of the substrate and catalyst. If the porous spacers are too close to the surface from which the gas is released, the alkaline aqueous electrolyte will lose contact with the electrode surface, rendering it inoperable. Optimal spacer spacing requires that bubbles escape from the surface and pores of the OER electrode, but also allow the electrolyte sufficient contact to continue transporting ions to that surface and promoting the OER reaction. For example, Figure 70A A suboptimal spacing is shown, in which bubbles 7002 generated by OER 7003 accumulate on the surface of electrolyte 140 and adhere to spacer 7004. For example, Figure 70B The optimal spacing is shown, where spacer 7004 is further away from OER 7003, and the bubbles 7002 generated by OER 7003 rise freely and burst on the surface of electrolyte 140. Furthermore, mechanical hardware (e.g.) Figure 70C The housing 7005 shown holds the OER electrode 7003 and Figure 70C The suboptimal configuration shown, conversely, does not prevent bubbles 7002 from escaping to the free surface of the electrolyte 140. Figure 70C In the suboptimal configuration shown, bubbles 7002 accumulate below the housing 7005, so that the OER electrode 7003 is not exposed to the electrolyte 140.

[0193] In a multilayer ORR electrode stack, each layer requires an air supply to the ORR electrode. Therefore, measures must be taken to deliver air to each layer of the stack. In some embodiments, a common air inlet can be used, with continuous layer-by-layer gas delivery in a lateral-vertical manner. For example, Figure 71A A single multi-branch tube 7102 is shown supplying gas 6903 to the lowest ORR electrode 6902 in the stack, and the gas 6903 bubbles upward through the offset outlet hole 6901a in the ORR electrode to the next higher layer. Figure 72DThis diagram illustrates how air, continuously transported layer by layer, maintains a liquid-gas seal at the outlet of each ORR chamber, chambers 1-4, by utilizing a P-trap feature 7250. As gas bubblees into each air chamber from gas inlet 7255 to gas outlet 7256, the liquid level in each chamber decreases until the bubbles escape from the P-trap portion 7250 of the air chamber. The gas is then captured by the inlet multi-branch of the ORR chamber above the previous one (preventing gas from escaping from the housing). After each P-trap, a port (or liquid drain 7252) is required to allow communication between the electrolyte outside and inside the multi-branch. This port allows pressure to be balanced as bubbles rise vertically from one ORR chamber to the next. The location of these ports must ensure that bubbles cannot enter the external electrolyte through the ports. A flow limiter 7251 can be added to the gas passage to slow unstable airflow rates between ORR chambers. The flow limiter 7251 can be designed to produce a uniform airflow across all chambers.

[0194] In some implementations, a common gas multi-branch can distribute gas to each layer of the ORR stack. Providing a unique air delivery for each layer allows for finer control over the flow rate and gas velocity of each layer. Figure 71B A multi-branch tube 7108 is shown that provides gas 6903 individually to each ORR electrode 7105. As bubbles rise through electrolyte 140, baffles or channels 7109 can deflect the bubbles upwards and away from the next ORR electrode 7105 layer.

[0195] Various implementation schemes can provide unsealed vertical ORR cathodes. For example, Figure 72AAn unsealed vertically immersed ORR cathode 7202 according to one embodiment is shown. A three-phase boundary must be maintained on the ORR electrode. This can be achieved with a sealed chamber with ORR walls and an internal gas volume, but conventional ORR electrodes are known to leak, and the leaking electrolyte fills the internal volume of this chamber. Furthermore, flooding a leaking ORR electrode with electrolyte may reverse the leakage problem, but this can be difficult to do in a sealed chamber. A high-walled, internally sealed chamber with an open bottom provides the advantages of both sealed and unsealed ORR mechanical embodiments. The high, semi-sealed walls with an internal pressurized gas volume supply oxygen to the ORR electrode. The open bottom provides a pathway for leaking electrolyte to exit the chamber. Internal pressure helps reduce electrolyte leakage through the ORR electrode. The unsealed vertically immersed ORR cathode 7202 can keep the electrodes parallel to each other for better electrochemical performance. The internal pressure of the unsealed vertically immersed ORR cathode 7202 chamber can be automatically regulated through the chamber's open bottom to the electrolyte. In another embodiment, air can be directed to the ORR electrode via a pipe trap or flow field to guide air through the ORR electrode. The same design feature can be used to continuously transmit airflow through multiple sections of a mechanically separated ORR electrode. The unsealed vertically immersed ORR cathode 7202 can be leak-proof due to the pressure difference between the electrolyte 140 inside and outside the cavity. For example, Figure 72B This illustrates the pressure difference between the pressure in the electrolyte 140 and the pressure within the cavity of the unsealed vertical immersion ORR cathode 7202 as the unsealed vertical immersion ORR cathode 7202 extends deeper into the electrolyte 140. Specifically, the pressure within the cavity can be constant at the depth (or height h) of the unsealed vertical immersion ORR cathode 7202, while the pressure in the electrolyte 140 increases with depth. Due to its open bottom, the unsealed vertical immersion ORR cathode 7202 can be overflow-proof. The internal pressure (Ph) of the unsealed vertical immersion ORR cathode 7202 can be set as the pressure of the electrolyte 140 at the opening depth of the unsealed vertical immersion ORR cathode 7202 (i.e., the height (h) from the surface of the electrolyte 140). The pressure of the electrolyte 140 at the opening depth can be equal to the density (ρ) of the electrolyte multiplied by gravity (g, e.g., 9.8 m / s²). 2 Multiply the height (h) by ρ. Therefore, Ph can be equal to ρ. g h. In some embodiments, bubbles / airflow can flow from the bottom of the unsealed vertically submerged ORR cathode 7202 into the electrolyte 140. In some embodiments, pressure balance with the electrolyte is regulated via a port from which air can escape as bubbles. Examples include... Figure 72CAs shown in the diagram. The size and shape of this port can control the pressure required to exit the chamber, thereby setting the pressure within the chamber. This pressure control is also used to control volumetric flow rate. This can also be achieved through the local geometry around the port. For example, a downward U-shaped bend can form a local geometry similar to a "pipe trap," through which gas must overcome a small hydrostatic head to escape the chamber. The length, area, and shape of this pipe trap or other geometry can adjust the airflow characteristics to meet the requirements. The gas can be discharged into the battery's electrolyte or discharged through a pipe connected to another liquid volume, where the relevant port size and shape are at the end of the pipe.

[0196] In various embodiments, an unsealed vertically immersed ORR cathode is characterized by one side having air supplied through a continuous transfer chamber on the air side. The ORR cathode may have an embedded current collector extending horizontally from either side of the electrode. To seal the exposed mesh from contact with the electrolyte, the assembly may include a vertical sealing strip isolating the current collector from the remaining electrolyte. The isolation area may be constructed of plastic sheets that are formed in a flap-like or rolled-up shape around the mesh, which has a conductive mechanism, to connect the current collector.

[0197] The cathode orientation relative to the anode (whether vertical or horizontal) can lead to strong electrical short circuits during assembly and operation. In various embodiments, the risk of electrical short circuits during assembly and operation can be reduced by using sheets of porous or solid polymer material to electrically insulate the current collector and / or active materials from each other. For example, plastic can be placed between the electrodes to prevent electrode short circuits. In some embodiments, the ORR housing can act as an insulator to prevent short circuits. Using polymer sheets and / or insulating housings can reduce the overall width of the electrode assembly because the physical spacing separating the electrodes can be reduced.

[0198] Various implementations may include sealed horizontally submerged electrodes. A sealed horizontally submerged electrode may include up to two sealed horizontal electrodes with a sealed air cavity between them. Many of these components may be stacked together. An advantage of a sealed horizontally submerged electrode solution may be that the electrodes are under uniform pressure throughout the region, thus providing a uniform pressure differential across the electrodes. Figure 73 An exemplary sealed horizontal immersion electrode 7300 is shown, which includes a first ORR electrode 7301 and a second ORR electrode 7302. In some embodiments, the sealed horizontal immersion electrode may include only the top ORR electrode, such as only ORR electrode 7301. In some embodiments, the sealed horizontal immersion electrode may include side ORR electrodes.

[0199] Figure 74A and Figure 74BA co-located ORR electrode 7402 and OER electrode 7403 configuration is shown for an embodiment. The ORR electrode 7402 requires oxygen (e.g., oxygen contained in air) to be supplied to it. In an electrochemical system using both the ORR electrode 7402 and the OER electrode 7403, the OER electrode 7403 can generate oxygen that can be used by the ORR electrode 7402. In various embodiments, the ORR electrode 7402 layer can be horizontally positioned, with the OER electrode 7403 material placed below it, such that the oxygen, which may be in the form of bubbles, generated by the OER electrode 7403 is trapped below the ORR electrode 7402. For example, Figure 74A One configuration is shown in which the ORR electrode 7402 and the OER electrode 7403 are spaced apart, with the ORR electrode 7402 positioned above the OER electrode 7403. The distance between electrodes 7402 and 7403 can vary. Other features may also aid in oxygen capture, such as a skirt 7404 extending from the ORR electrode 7402 or an ORR electrode 7402 formed as an inverted cup. Figure 74B Another embodiment is shown in which the OER electrode 7403 is porous and in contact with the ORR electrode 7402. Supplemental gas (e.g., air) can enter the chamber below the ORR electrode 7402 through or around the OER electrode 7403 (in the case of a porous electrode). In various embodiments, the OER electrode 7403 can be very close to, or even in contact with, the gas diffusion side of the ORR electrode 7402.

[0200] Figure 75 A packaging configuration 7500 for the ORR electrode 7502 according to an embodiment is shown. The ORR electrode 7502 can be packaged into a large configuration through a secondary molding process. The configuration 7500 may include multiple narrow strips of ORR electrodes 7502 and current collector strips 7503, which are secondary molded together by plastic or epoxy resin 7504 to form a self-supporting structure. Secondary molding or other sealing methods (epoxy resin, etc.) allow for the sealing and integration of sub-assemblies with a smaller number of parts in a single step. The advantages of the configuration 7500 may include a smaller number of parts, shorter assembly time, a very thin geometry to achieve high energy density, and flexibility for variations in architectural geometry.

[0201] Figures 76A-76D Cross-sectional views of concave horizontal ORR electrodes in various embodiments are shown. Figures 76A-76DAs shown, the ORR electrode sheet 7603 can be connected to the current collector 7602 via a junction point, or extend over the current collector and form a downward-facing, approximately semi-circular or other generally concave shape (e.g., an A-frame, etc.) to trap air below the surface of the ORR electrode between the ORR electrode and the electrolyte 140. The approximately semi-circular shape may have three, four, five, or more vertices. In various embodiments, the current collector 7602 may be present at each vertex. Figure 76A An ORR electrode including an ORR electrode sheet 7603 is shown, the ORR electrode sheet 7603 being formed as a transverse member connected together in an a-type frame cross-section construction, and having three current collectors 7602, wherein one current collector 7602 is located at each end of the ORR electrode sheet 7603, and one current collector 7602 is located between the ORR electrode sheets 7603. Figure 76B An ORR electrode including an ORR electrode sheet 7603 is shown, the ORR electrode sheet 7603 being formed as a transverse member connected together in a generally semi-circular structure and having four current collectors 7602, wherein one current collector 7602 is located at each end of the ORR electrode sheet 7603 and two current collectors 7602 are located between the ORR electrode sheets 7603. Figure 76C An ORR electrode including an ORR electrode sheet 7603 is shown, the ORR electrode sheet 7603 being formed as a transverse member connected together in a generally semi-circular configuration and having five current collectors 7602, wherein one current collector 7602 is located at each end of the ORR electrode sheet 7603 and three current collectors 7602 are located between the ORR electrode sheets 7603. Figure 76D An ORR electrode including an ORR electrode sheet 7603 is shown, the ORR electrode sheet 7603 being formed as transverse members connected together in a generally semi-circular structure as a half-tube.

[0202] Figure 77C A comparison of the pressure of electrolyte 140 at ORR electrode 7702 is shown in different pressurized air chamber configurations 7700 and 7703. Pressure imbalance on opposite sides of ORR electrode 7702 can lead to strain or leakage or movement of the three-phase boundary through the thickness of porous ORR electrode 7702. The use of air chambers, such as one air chamber shown on the left side of Figure 77, or multiple air chambers (such as the four air chambers 7705, 7706, 7707, and 7708 shown on the right side of Figure 77), allows adjustable pressure along the ORR air chambers to balance the pressure from electrolyte 140. This can be done using compressed air, oxygen, CO2-free air, or any combination thereof, and can be done under varying humidity. This can be simply balancing the pressure, or the pressure on the air side can be slightly increased at each point to prevent electrolyte 140 from leaking into the air chamber. These chambers in a single electrode can be coupled with, for example, Figure 77A In the other independent electrodes shown, chambers with the same electrolyte depth share air, with each chamber P1, P2, and P3 sharing air with each other, respectively. These pressures can be achieved by venting the chambers (e.g., 7705, 7706, 7707, 7708) to their local electrolytes, driving them to gas pressures experienced near the chamber, or driving them to gas pressures into separate liquid chambers at specific depths to match the pressures experienced by the chambers. Figure 77B The figure shows the hydrostatic pressure of tubes of predetermined lengths, where tube lengths h1, h2, and h3 are associated with their respective chambers P1, P2, and P3. By controlling the pressure in the gas chamber using the hydrostatic pressure of the second container, the gas flow can be separated from the electrolyte, thereby minimizing carbonation and oxidation.

[0203] Figures 78A-85C Aspects of unsealed horizontal submerged ORR electrode and reactor designs according to various embodiments are illustrated. Unsealed horizontal submerged ORR electrode and reactor may also be referred to as UHS reactors. In some embodiments, the UHS reactor architecture may be configured to be mounted in a repeating anode-cathode-anode-cathode array, wherein the number and precise dimensions of the repeating units vary in various embodiments. The UHS reactor may include a current collector made of sheet metal, which may be stamped, punched, rolled, formed, rolled, or welded. The material of the current collector may include nickel-plated carbon steel or any other suitable material. The UHS reactor designs of various embodiments may allow removal of the anode or cathode without major disassembly. In various embodiments, the cathode may be a vertical sandwich of ORR / ORR layers. The plastics used in the UHS reactor may include polypropylene, HDPE, and / or XLPE (cross-linked polyethylene (PE)), which may be advantageous for applications requiring creep resistance. The plastic may be used in parts produced by injection molding, extrusion, hot plate welding, blow molding / rotary vacuum forming, and / or any other method suitable for the selected plastic type.

[0204] Figures 78A-78C The UHS configuration according to the implementation scheme is shown. Figures 78A-78C In this configuration, the UHS may include an ORR electrode with a roll crimp 7807 that seals the ORR to an ORR current collector 7802. The UHS may have an arc frame 7800, a molding frame 7803, and the OER may be constrained by a top flange 7804 and a bottom flange 7805. The roll crimp 7807 seals the ORR to the ORR current collector 7802. The ORR current collector 7802 may be a stamped ORR current collector 7802. Figure 78B It shows Figure 78A Bottom view of the UHS. Figure 78CIt shows the fit with Figure 78A and 78B An exemplary coil configuration used with UHS.

[0205] Figures 79A-79C A UHS configuration according to another embodiment is shown, where the ORR current collectors 7902 are stacked. Figures 79A-79C In this configuration, the UHS may include ORR electrodes stacked in a rolled ORR current collector 7902. The UHS may have an injection-molded frame 7903, and the OER may be constrained by a top flange and a bottom flange of the frame. The rolled portion of the ORR current collector 7902 may seal the ORR within the ORR current collector 7902. The ORR current collector 7902 may be a stamped ORR current collector 7902. Figure 79B It shows Figure 79A Bottom view of the UHS. Figure 79C It shows the fit with Figure 79A and 79B An exemplary coil compression and spacing configuration used with UHS.

[0206] Figures 80A-80B A UHS configuration according to another embodiment is shown, wherein the UHS has an asymmetric current collector frame. Figures 80A-80B In this configuration, the UHS may include ORR electrodes stacked within a rolled ORR current collector 8002. The rolled element seals the ORR within the ORR current collector 8002. The UHS may include an arched frame 8000. Similarly, a roll-formed OER current collector 8005 may be rolled onto the OER electrode. The UHS may have an extruded frame.

[0207] Figures 81A-81B A UHS configuration according to another implementation scheme is shown. Figures 81A-81B In this configuration, the UHS may include ORR electrodes stacked in a coiled ORR current collector 8102. The coil seals the ORR to the ORR current collector 8102. Similarly, an OER current collector 8005 may be coiled to an OER. The OER current collector 8105 may be located inside the ORR current collector 8102, and an insulator 8106 (e.g., a polypropylene insulator) may separate the current collectors 8105 and 8102. Figure 82 As shown Figures 81A-81B The different configurations of the UHS shown are further separated from the OER by the spacing of the coils in current collectors 8105 and 8102 and the size of the insulator 8106.

[0208] Figures 83A-83D A UHS configuration according to another implementation scheme is shown. Figures 83A-83DIn this configuration, the UHS may include ORR electrodes stacked in a wedge-shaped, rolled ORR current collector 8302. The wedge rolling seals the ORR onto the ORR current collector 8302. The ORR current collector 8302 may be stamped or rolled and may be formed, for example, by XPLE. Similarly, an OER current collector 8305 may be rolled onto an OER. The OER current collector 8305 may be located inside the ORR current collector 8302, and an insulator 8306 (e.g., a polypropylene insulator) may form an internal support / wedge that supports the OER current collector 8305 and can separate the current collectors 8305 and 8302. The UHS may include a snap-fit ​​fitting 8310 for assembling the pre-rolled fitting. The UHS may have an arcuate frame 8300.

[0209] Figure 84 It shows Figures 83A-83D The UHS end condition (or cap) where the ORR current collector 8302 can be soldered to the vertical bus 8412. The end condition (or cap) may include an extruded OER / ORR insulator support wedge 8418, which may include a series of holes 8416 for air management.

[0210] Figures 85A-85C Anode configurations for UHS are illustrated according to various embodiments. The anode may be formed from an anode component 8500, which is formed as a folded flat plate, a portion of which is... Figure 85A As shown in the figure. The plate can be a solid plate, a perforated plate, and / or an expanded plate, for example, having Figure 85B The diagram shows an expanded plate with portions 8501 or 8502. In some embodiments, anode components (e.g., components 8500a and 8500b) can be filled, compressed together, and welded together. For example, a first component 8500a can be filled, and the second portion 8500b can compress the first component 8500a. Components 8500a and 8500b can be welded, and a weld 8506 (or spot weld) can hold components 8500a and 8500b together. This process can be repeated for other anode components until the anodes are completely stacked.

[0211] Figures 86A-87B The bubble flow characteristics of the embodiment in the UHS reactor and the configuration of the UHS reactor in the embodiment are shown. Figure 86A The design of the 8602, which exhibits a violent bubble flow, is shown. Figure 86B The design of the 8603 exhibits a dramatic bubble flow. Figure 86C A stacked core reactor 8604 is shown, in which bubbles escape from the sides of the stack. Figure 86DThe UHS mesh 8605 is shown, in which holes are drilled in the sloping edge of the cup, such as 4 deep 5 wide 1 / 16 inch holes. Figure 86E The UHS valve 8606 is shown, in which a low-carbon steel mesh 8607 is connected to a Teflon mesh 8608 above the opening of the UHS cup. Figure 87A The UHS linear design 8702 is shown, including a custom anode. Figure 87B The design of component 8703 with a linear design of a standard scale anode is shown. Figure 87C The design of component 8704 with a matching symmetrical design is shown.

[0212] Figure 88S Exemplary aspects of a sealed, vertically submerged (SVS) ORR electrode according to various embodiments are shown. Figure 88S As shown at the top, the SVS repeating unit may include OER, anode, ORR, and anode modes that are linearly repeated throughout the assembly. An exemplary ORR membrane assembly is shown, as well as an embodiment of the interaction between the inlet, outlet, and ORR membrane.

[0213] In various implementations, a sealed vertically submerged (SVS) ORR electrode can be combined with a flow field that directs air or oxygen flow from multiple branches to the ORR electrode sheet. Figures 88A-88E An exemplary aspect of the SVSORR electrode configuration of this embodiment is shown. The flow field 8801 may be made of plastic (e.g., polypropylene, HDPE) or metal (e.g., steel, nickel). The flow field 8801 may also serve as a current collector and / or may include an embedded current collector 8804. The flow field may be compressed relative to the ORR electrode 8820 so that gas can be directly delivered from the airflow channel 8801 to the ORR electrode. The flow field can collect and guide airflow. The flow field 8801 may be made of a metal and plastic insulating material. The flow field 8801 may be placed on the hydrophobic coating side of the sheet-like ORR electrode. The flow field 8801 may be formed by a series of channels 8802, the width of which is 0.1 mm to 5 cm and the depth of which is 0.1 mm to 1 cm. The flow field 8801 may include a gas diffusion layer (GDL) 8805. Figure 88FAAs shown, the flow channels can take the form of parallel, interdigitated, serpentine, or spiral geometric patterns. In some embodiments, the flow channels in the flow field can present an elliptical cross-section that allows for small landing contacts between the ORR electrode and the flow field, which can achieve high flow velocities at low pressure drops. The flow field can allow control over the airflow through and / or into the ORR electrode, with different design patterns for different operating power and different overflow mitigation measures. The flow field can allow for the use of a wider range of ORR electrode design arrays, particularly regarding oxygen transport through the thickness of the ORR electrode and into the catalyst layer. In some embodiments, the conductive flow field can allow the use of air electrodes without embedded current collectors. For use in alkaline electrolyte systems, the conductive flow field can be constructed of carbon, graphite, nickel, or nickel-plated steel.

[0214] A serpentine flow field allows for a longer residence time of reactant gases in an electrochemical system, which can help increase air utilization (or reduce stoichiometry). However, it is well known that serpentine flow fields exhibit significant pressure drops due to the presence of narrow, tortuous gas delivery channels. Figure 88FB As shown, in some implementations, dividing the serpentine flow path into multiple segments can achieve joint optimization of air utilization and pressure drop. The serpentine flow path can be divided into multiple segments, with multiple inlet gas delivery points and outlet gas delivery points located in larger inlet and outlet multi-branch pipes. The number of connected serpentine segments can be adjusted in the design to optimize air utilization and pressure drop. More connected serpentine segments can result in higher air utilization and higher pressure drop, while fewer connected serpentine segments may result in lower air utilization and lower pressure drop.

[0215] In some implementations, the flow channel in the flow field may be conical, which can regulate the air pressure within the air flow channel 8810. Figure 88G A conical airflow channel is illustrated. As air flows from the inlet (bottom of the battery) to the outlet (top of the battery), the conical flow channel can limit airflow by applying a higher pressure drop. In some embodiments, the air volumetric flow rate remains constant, and the increased air pressure generated within the flow channel can balance the hydraulic pressure at the bottom of the battery. Figure 88HAs shown, in some implementations, the geometry of the flow field, such as the width of the channels and their configuration (e.g., serpentine, interdigitated), is used to alter the pressure along the air channels within a single subassembly, thereby obtaining the desired pressure gradient pattern. This pattern can be matched to the surrounding hydrostatic pressure at the electrode depth. For example, the highest-pressure air can enter at the bottom of the chamber, where the surrounding electrolyte pressure is highest. As the gas moves upward through the flow field, the resistance in the flow field (similar to pipe friction) reduces the air pressure. If the flow field resistance is designed to reduce the pressure in the airflow at an appropriate rate, it can be designed to match the smaller electrolyte pressure moving upward within the container to maintain a constant transelectrode pressure gradient. Decompression geometry (e.g., orifices) can also be used to alter the pressure along the air channels. Figure 88I The pressure of the airflow channels within the ORR electrode subassembly is shown. In some embodiments, there may be only one large flow cavity behind the ORR electrode. In other embodiments, there may be multiple flow channels behind the ORR electrode to guide airflow. The tapered airflow channels can be economically manufactured using additive manufacturing techniques (such as 3D printing). The tapered airflow channels can also be manufactured by extrusion or injection molding.

[0216] like Figure 88J-Figure 88LAs shown, in various embodiments, the sealed vertically submerged (SVS) ORR electrode can be constructed from a sheet / film air electrode assembly. The air electrode 8853 can be constructed from a monolithic electrode material 8852, which folds itself around a mechanically defined airflow field 8850 and is sealed or rolled at the two resulting vertical edges by edge-pressed seals 8854. In such embodiments, the assembly can form a closed, meandering channel for delivering air into the interior of the electrode structure, effectively forming a pouch-like assembly that can be immersed in an electrolyte bath of a metal-air battery pack. The hydrostatic pressure of the electrolyte can partially or completely hold the assembly together. In some embodiments, the assembly is constructed in such a way that the internal chamber is hydraulically isolated from the external electrolyte, allowing air to flow through the interior of the assembly and react with the electrolyte, which is controllably wetted to the outer surface of the electrode material. In some embodiments, the air electrode material can have sufficient mechanical strength and integrity to withstand its own folding and edge sealing. In some embodiments, the component may include an additional top seal 8860, supplemented by a rolled structure, a flap with fasteners, adhesive, or gasket material. In some embodiments, the additional top seal may be thermowelded or ultrasonically welded. The top seal 8860 may also serve as an electrical contact with the ORR electrode material. In some embodiments, the electrode material may have high in-plane conductivity, such that a flow field made of conductive material can replace the current collector originally embedded in the ORR electrode material.

[0217] Current collectors designed for vertically oriented OER electrodes, composed of foamed metal or porous sintered metal plates, are prone to large resistive losses (i.e., iR voltage drop). Mechanical failure can also occur in the OER electrode portion that mechanically interacts with the current collector. As the geometry of the reactor and electrode increases, both large resistive losses and the incidence of mechanical failure become more prevalent. Figure 88M-Figure 88Q As shown, in some embodiments, the OER current collector design may include small spikes that are cut and die-cast perpendicular to the out-of-plane plane of the plate. The current collector may be clamped onto the OER electrode, wherein the spikes are inserted into the OER electrode to provide a larger contact area with the foam, while the current collector has a porous structure to allow electrolyte to flow through it. In another embodiment, by using... Figure 88R The two metal plates shown are fixed to both sides of the OER electrode, mechanically fitting the current collector onto the OER electrode. In this embodiment, the two plates can press and close the orifice of the OER electrode in the clamping area, thereby subsequently reducing the contact resistance between the OER electrode and the current collector. In another embodiment, metal or plastic spacers can be introduced between the metal current collector plates to limit the maximum permissible strain on the OER electrode.

[0218] Figure 89 Exemplary aspects of an unsealed, horizontally submerged (UHS) ORR electrode according to various embodiments are shown. Figure 89 As shown in the figure above, the ORR and OER electrode pairs can be air-separated and arranged on top of each other, with the electrode posts or ORR and OER electrodes separated by an anode structure. Figure 89 The figure below shows a cross-sectional view of the UHS ORR electrode. Figure 90 An exemplary container for a repeating ORR electrode assembly is shown. Figure 90 The container may include SVS type electrode assemblies, such as those shown in Figure 88, or UHS electrode assemblies, such as... Figure 89 Those shown. Both the SVS ORR electrode assembly and the UHS ORR electrode assembly are suitable for repeating electrode assemblies (in parallel) in the same container type.

[0219] Figure 91C Examples of pressure gradient mitigation for sealed ORR electrodes according to various embodiments are shown. Uneven pressure distribution can damage ORR electrodes or cause premature aging due to physical or electrochemical aging mechanisms. To maintain a stable and constant pressure gradient at the three-phase boundary of the ORR electrode, air distribution multi-branch pipes, percolators, a series of orifices, and / or porous plate systems can be used to vary the air pressure at different depths. Figure 91 illustrates such a porous plate system and the pressure gradient at the height of the ORR electrode.

[0220] ORR electrodes can be designed as components introduced into metal-air battery packs, making their mechanical structure similar to a plate-and-frame heat exchanger, and having features such as Figure 91B The diagram shows alternating ORR plates and inactive barrier plates. In such an embodiment, one fluid is an electrolyte and the other is air. In another embodiment, the ORR electrode assembly can be designed similarly to a spirally wound membrane filter cartridge, having alternating ORR layers and inactive barrier layers, wherein, as shown... Figure 91A As shown, one fluid is an electrolyte and the other is air. In another embodiment, the ORR electrode assembly can resemble a spirally wound heat exchanger with alternating ORR plates and inactive barrier plates, where one fluid is an electrolyte and the other is air.

[0221] Iron anodes for alkaline batteries, composed of DRI pellets such as iron-air, iron-nickel, or iron-MnO2, may require compression of the DRI pellets to improve inter-pellet conductivity and usable capacity. Mechanical compression methods can typically significantly increase the hardware and assembly costs of the component. Figure 92The following method illustrates the key points of simultaneously compressing and retaining DRI pellets in large components under constant strain. A porous metal current collector cage is filled with DRI pellets. A current collector cap is pressed into the DRI pellet bed under a load sufficient to strain the DRI pellets beyond the desired final value. The current collector cap and cage are mechanically fitted together using a mechanical locking feature. Upon release of the load, the mechanical locking feature maintains the cap and cage in the fitted configuration. Releasing the load releases some of the elastic strain now mechanically retained in the DRI pellets by the cap. The DRI pellets are thus held in place under compressive load and strain by the mechanical locking mechanism.

[0222] It can be done as follows Figure 93 The additional method illustrated focuses on the simultaneous compression and retention of large assemblies of DRI pellets under constant strain. A porous metal current collector cage is filled with DRI pellets. A threaded rod is mechanically fitted to the bottom of the current collector cage via welding or mechanical fasteners. A current collector cap, containing a hole pattern matching the bolt pattern, is mounted on top of the DRI pellet bed, above the threaded rod. The cap is pressed down with a threaded nut, applying a compressive load to the DRI pellets. The threaded nut can be a lock nut.

[0223] Various implementations can provide devices and / or methods for large-capacity energy storage systems, such as Long-Duration Energy Storage (LODES) systems, Short-Duration Energy Storage (SDES) systems, etc. As an example, various implementations can provide battery packs (e.g., battery packs of 100, 500, etc.) for large-capacity energy storage systems, such as battery packs for LODES systems. Renewable energy is becoming increasingly prevalent and cost-effective. However, many renewable energy sources face intermittency issues that hinder their adoption. The intermittency trend of renewable energy can be mitigated by pairing renewable energy with large-capacity energy storage systems (e.g., LODES systems, SDES systems, etc.). To support the adoption of combined generation, transmission, and storage systems (e.g., power plants with renewable energy sources paired with large-capacity energy storage systems and transmission facilities located at either power plant and / or large-capacity energy storage system), there is a need for devices and methods that support the design and operation of such combined generation, transmission, and storage systems, such as the devices and methods of the various implementations described herein.

[0224] A combined generation, transmission, and storage system can be a power plant comprising one or more power sources (e.g., one or more renewable power sources, one or more non-renewable power sources, a combination of renewable and non-renewable power sources, etc.), one or more transmission facilities, and one or more large-capacity energy storage systems. The transmission facilities of any power plant and / or large-capacity energy storage system can be optimized in conjunction with the generation and storage systems, or constraints can be imposed on the design and operation of the generation and storage systems. Under various design and operational constraints, the combined generation, transmission, and storage system can be configured to meet various output objectives.

[0225] Figures 94-102 Various exemplary systems are illustrated, wherein one or more aspects of various implementations can be used as part of a large-capacity energy storage system (e.g., LODES system, SDES system, etc.). For example, as Figure 1A-Figure 93 The battery packs of the various embodiments described herein can be used as battery packs for large-capacity energy storage systems (e.g., LODES systems, SDES systems, etc.), and / or the various electrodes described herein can be used as components of large-capacity energy storage systems. As used herein, the term "LODES system" can mean a large-capacity energy storage system configured to have a rated duration (energy / power ratio) of 24 hours (h) or longer, such as a duration of 24 h, a duration of 24 h to 50 h, a duration of more than 50 h, a duration of 24 h to 150 h, a duration of more than 150 h, a duration of 24 h to 200 h, a duration of more than 200 h, a duration of 24 h to 500 h, a duration of more than 500 h, etc.

[0226] Figure 94An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, electrodes of various embodiments described herein, etc. LODES system 9404 may be electrically connected to a wind farm 9402 and one or more transmission facilities 9406. Wind farm 9402 may be electrically connected to transmission facilities 9406. Transmission facilities 9406 may be electrically connected to a power grid 9408. Wind farm 9402 may generate electricity and may output the generated electricity to LODES system 9404 and / or transmission facilities 9406. LODES system 9404 may store the electricity received from wind farm 9402 and / or transmission facilities 9406. LODES system 9404 may output the stored electricity to transmission facilities 9406. Transmission facility 9406 can output electricity received from one or both of wind farm 9402 and LODES system 9404 to grid 9408, and / or can receive electricity from grid 9408 and output that electricity to LODES system 9404. Wind farm 9402, LODES system 9404, and transmission facility 9406 together can constitute power plant 9400, which can be a combined power generation, transmission, and storage system. Electricity generated by wind farm 9402 can be directly supplied to grid 9408 via transmission facility 9406, or it can be first stored in LODES system 9404. In some cases, the electricity supplied to grid 9408 can come entirely from wind farm 9402, entirely from LODES system 9404, or from a combination of wind farm 9402 and LODES system 9404. The power dispatching of the combined wind farm 9402 and LODES system 9404 from power plant 9400 can be controlled according to a defined long-term (multi-day or even multi-year) plan, or according to the day-ahead (24-hour forecast) market conditions, or according to the hourly market conditions, or in response to real-time pricing signals.

[0227] As an example of power plant 9400 operation, LODES system 9404 can be used to reshape and “consolidate” the electricity generated by wind farm 9402. In one such embodiment, wind farm 9402 can have a peak generating output (capacity) of 260 MW and a capacity factor (CF) of 41%. LODES system 9404 can have a rated power (capacity) of 106 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 15,900 MWh. In another such example, wind farm 9402 can have a peak generating output (capacity) of 300 MW and a capacity factor (CF) of 41%. LODES system 9404 can have a rated power of 106 MW, a rated duration (energy / power ratio) of 200 h, and an efficiency of 21,200 MWh. In another such example, wind farm 9402 can have a peak generating output (capacity) of 176 MW and a capacity factor (CF) of 53%. LODES system 9404 can have a rated power (capacity) of 88 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 13,200 MWh. In yet another such example, wind farm 9402 can have a peak generating output (capacity) of 277 MW and a capacity factor (CF) of 41%. LODES system 9404 can have a rated power (capacity) of 97 MW, a rated duration (energy / power ratio) of 50 h, and an efficiency of 4,850 MWh. In yet another such example, wind farm 9402 can have a peak generating output (capacity) of 315 MW and a capacity factor (CF) of 41%. The LODES 9404 system has a rated power (capacity) of 110 MW, a rated duration (energy / power ratio) of 25 h, and an energy efficiency of 2,750 MWh.

[0228] Figure 95 An exemplary system is shown, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system combining one or more aspects of various embodiments can be LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. Figure 95 The system can be similar to Figure 94The system, except that wind farm 9402 can be replaced by photovoltaic (PV) farm 9502. LODES system 9404 can be electrically connected to PV farm 9502 and one or more transmission facilities 9406. PV farm 9502 can be electrically connected to transmission facilities 9406. Transmission facilities 9406 can be electrically connected to grid 9408. PV farm 9502 can generate electricity and can output the generated electricity to LODES system 9404 and / or transmission facilities 9406. LODES system 9404 can store electricity received from PV farm 9502 and / or transmission facilities 9406. LODES system 9404 can output the stored electricity to transmission facilities 9406. Transmission facilities 9406 can output electricity received from one or both of PV farm 9502 and LODES system 9404 to grid 9408 and / or can receive electricity from grid 9408 and output that electricity to LODES system 9404. PV field 9502, LODES system 9404, and transmission facility 9406 together constitute power plant 9500, which can be a combined power generation, transmission, and storage system. Electricity generated by PV field 9502 can be directly supplied to grid 9408 via transmission facility 9406, or it can be stored first in LODES system 9404. In some cases, the electricity supplied to grid 9408 can come entirely from PV field 9502, entirely from LODES system 9404, or a combination of PV field 9502 and LODES system 9404. Power dispatching of the combined PV field 9502 and LODES system 9404 from power plant 9500 can be controlled according to a defined long-term (multi-day or even multi-year) plan, or according to day-ahead (24-hour forecast) market conditions, or according to hourly market conditions, or in response to real-time pricing signals.

[0229] As an example of power plant 9500 operation, LODES system 9404 can be used to reshape and “consolidate” the electricity generated by PV plant 9502. In one such embodiment, PV plant 9502 can have a peak generating output (capacity) of 490 MW and a capacity factor (CF) of 24%. LODES system 9404 can have a rated power (capacity) of 340 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 51,000 MWh. In another such embodiment, PV plant 9502 can have a peak generating output (capacity) of 680 MW and a capacity factor (CF) of 24%. LODES system 9404 can have a rated power (capacity) of 410 MW, a rated duration (energy / power ratio) of 200 h, and an efficiency of 82,000 MWh. In yet another such embodiment, PV plant 9502 can have a peak generating output (capacity) of 330 MW and a capacity factor (CF) of 31%. The LODES system 9404 can have a rated power (capacity) of 215 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 32,250 MWh. In another such example, the PV plant 9502 can have a peak power output (capacity) of 510 MW and a capacity factor (CF) of 24%. The LODES system 9404 can have a rated power (capacity) of 380 MW, a rated duration (energy / power ratio) of 50 h, and an efficiency of 19,000 MWh. In yet another such example, the PV plant 9502 can have a peak power output (capacity) of 630 MW and a capacity factor (CF) of 24%. The LODES system 9404 can have a rated power (capacity) of 380 MW, a rated duration (energy / power ratio) of 25 h, and an efficiency of 9,500 MWh.

[0230] Figure 96 An exemplary system is shown, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system combining one or more aspects of various embodiments can be LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. Figure 96 The system can be similar to Figure 94 and Figure 95The system, except for wind farm 9402 and photovoltaic (PV) farm 9502, can all be generators working together in power plant 9600. PV farm 9502, wind farm 9402, LODES system 9404, and transmission facility 9406 together constitute power plant 9600, which can be a combined power generation, transmission, and storage system. Electricity generated by PV farm 9502 and / or wind farm 9402 can be directly supplied to grid 9408 via transmission facility 9406, or it can be first stored in LODES system 9404. In some cases, the electricity supplied to grid 9408 may come entirely from PV farm 9502, entirely from wind farm 9402, entirely from LODES system 9404, or from a combination of PV farm 9502, wind farm 9402, and LODES system 9404. Power dispatching from the combined wind farm 9402, PV farm 9502 and LODES system 9404 of power plant 9600 can be controlled according to a defined long-term (multi-day or even multi-year) plan, or according to the day-ahead (24-hour forecast) market conditions, or according to the hourly market conditions, or in response to real-time pricing signals.

[0231] As an example of power plant 9600 operation, the LODES system 9404 can be used to reshape and “consolidate” the electricity generated by wind farm 9402 and PV farm 9502. In one such embodiment, wind farm 9402 can have a peak generating output (capacity) of 126 MW and a capacity factor (CF) of 41%, and PV farm 9502 can have a peak generating output (capacity) of 126 MW and a capacity factor (CF) of 24%. LODES system 9404 can have a rated power (capacity) of 63 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 9,450 MWh. In another such example, wind farm 9402 can have a peak generating output (capacity) of 170 MW and a capacity factor (CF) of 41%, and PV farm 9502 can have a peak generating output (capacity) of 110 MW and a capacity factor (CF) of 24%. The LODES system 9404 can have a rated power (capacity) of 57 MW, a rated duration (energy / power ratio) of 200 h, and an efficiency of 11,400 MWh. In another such example, the wind farm 9402 can have a peak power output (capacity) of 105 MW and a capacity factor (CF) of 51%, and the PV farm 9502 can have a peak power output (capacity) of 70 MW and a capacity factor (CF) of 31%. The LODES system 9404 can have a rated power (capacity) of 61 MW, a rated duration (energy / power ratio) of 150 h, and an efficiency of 9,150 MWh. In another such example, the wind farm 9402 can have a peak power output (capacity) of 135 MW and a capacity factor (CF) of 41%, and the PV farm 9502 can have a peak power output (capacity) of 90 MW and a capacity factor (CF) of 24%. The LODES system 9404 can have a rated power (capacity) of 68 MW, a rated duration (energy / power ratio) of 50 h, and an efficiency of 3,400 MWh. In another such example, the wind farm 9402 can have a peak power output (capacity) of 144 MW and a capacity factor (CF) of 41%, while the PV farm 9502 can have a peak power output (capacity) of 96 MW and a capacity factor (CF) of 24%. The LODES system 9404 can also have a rated power (capacity) of 72 MW, a rated duration (energy / power ratio) of 25 h, and an efficiency of 1,800 MWh.

[0232] Figure 97An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 may be electrically connected to one or more transmission facilities 9406. In this way, LODES system 9404 can operate in a “standalone” manner to arbitrate energy around market prices and / or avoid transmission constraints. LODES system 9404 may be electrically connected to one or more transmission facilities 9406. Transmission facilities 9406 may be electrically connected to a power grid 9408. LODES system 9404 may store electricity received from transmission facilities 9406. LODES system 9404 may output its stored electricity back to transmission facilities 9406. The transmission facility 9406 can output power received from the LODES system 9404 to the power grid 9408 and / or can receive power from the power grid 9408 and output that power to the LODES system 9404.

[0233] The LODES system 9404 and transmission facility 9406 can together constitute a power plant 900. As an example, the power plant 900 can be located downstream of the transmission constraint, close to power consumption. In such an example of a downstream power plant 9700, the LODES system 9404 can have a duration of 24 hours to 500 hours and can undergo one or more full discharges throughout the year to support peak power consumption when transmission capacity is insufficient to serve customers. Additionally, in such an example of a downstream power plant 9700, the LODES system 9404 can undergo several shallow discharges (daily or at a higher frequency) to arbitrate the difference between nighttime and daytime electricity prices and reduce the total cost of electricity service to customers. As a further example, the power plant 9700 can be located upstream of the transmission constraint, close to power generation. In such an example of an upstream power plant 9700, the LODES system 9404 can have a duration of 24 hours to 500 hours and can undergo one or more full charges throughout the year to absorb excess generation when transmission capacity is insufficient to distribute electricity to customers. Additionally, in such an upstream power plant 9700 example, the LODES system 9404 can undergo several shallow charging and discharging cycles (daily or at a higher frequency) to arbitrate the difference between nighttime and daytime electricity prices and maximize the output value of the power generation facility.

[0234] Figure 98An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 may be electrically connected to commercial and industrial (C&I) customers 9802, such as data centers, factories, etc. LODES system 9404 may be electrically connected to one or more transmission facilities 9406. Transmission facilities 9406 may be electrically connected to a power grid 9408. Transmission facilities 9406 may receive power from the power grid 9408 and output that power to LODES system 9404. LODES system 9404 may store the power received from transmission facilities 9406. LODES system 9404 may output its stored power to C&I customers 9802. In this way, LODES system 9404 can operate to reshape the electricity purchased from grid 608 to match the consumption patterns of C&I customer 9802.

[0235] LODES system 9404 and transmission facility 9406 can together constitute power plant 9800. As an example, power plant 9800 can be located near electricity consumption, i.e., near C&I customer 9802, for example, between grid 9408 and C&I customer 9802. In such an embodiment, LODES system 9404 can have a duration of 24 hours to 500 hours and can purchase electricity from the market to charge LODES system 9404 when electricity is cheaper. LODES system 9404 can then discharge to provide electricity to C&I customer 9802 when market prices are high, thus offsetting the market purchases by C&I customer 9802. As an alternative configuration, power plant 9800 can be located between renewable energy sources such as solar farms, wind farms, etc., instead of between grid 9408 and C&I customer 9802, and transmission facility 9406 can be connected to the renewable energy source. In such an alternative embodiment, the LODES system 9404 can have a duration of 24 hours to 500 hours, and the LODES system 9404 can be charged when renewable output is available. The LODES system 9404 can then discharge to provide renewable power generation to C&I customer 9802, thereby meeting some or all of the power demand of C&I customer 9802.

[0236] Figure 99An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 may be electrically connected to a wind farm 9402 and one or more transmission facilities 9406. Wind farm 9402 may be electrically connected to transmission facilities 9406. Transmission facilities 9406 may be electrically connected to a C&I customer 9802. Wind farm 9402 can generate electricity, and wind farm 9402 can output the generated electricity to LODES system 9404 and / or transmission facilities 9406. LODES system 9404 may store the electricity received from wind farm 9402.

[0237] LODES system 9404 can output stored electricity to transmission facility 9406. Transmission facility 9406 can output electricity received from one or both of wind farm 9402 and LODES system 9404 to C&I customer 9802. Wind farm 9402, LODES system 9404, and transmission facility 9406 together can constitute power plant 9900, which can be a combined power generation, transmission, and storage system. Electricity generated by wind farm 9402 can be directly supplied to C&I customer 9802 through transmission facility 9406, or it can be stored in LODES system 9404 first. In some cases, the electricity supplied to C&I customer 9802 can come entirely from wind farm 9402, entirely from LODES system 9404, or a combination of wind farm 9402 and LODES system 9404. The LODES system 9404 can be used to reshape the electricity generated by the wind farm 9402 to match the consumption patterns of the C&I customer 9802. In one such instance, the LODES system 9404 can have a duration of 24 hours to 500 hours and can be charged when the renewable generation of the wind farm 9402 exceeds the load of the C&I customer 9802. The LODES system 9404 can then discharge when the renewable generation of the wind farm 9402 falls below the load of the C&I customer 9802, in order to provide a reliable renewable configuration for the C&I customer 9802 to offset some or all of the C&I customer 9802's electricity consumption.

[0238] Figure 12 illustrates an exemplary system in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system combining one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 could include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 could be part of a power plant 10000 for integrating a large amount of renewable energy in a microgrid and coordinating the output of renewable power generation (e.g., through PV field 9502 and wind farm 9402) and existing thermal power generation (e.g., through thermal power plant 10002, such as a gas-fired power plant, coal-fired power plant, diesel generator set, etc., or a combination of thermal power generation methods), while renewable and thermal power generation provide highly available loads for C&I customers 9802. The microgrid (e.g., a microgrid consisting of power plant 10000 and thermal power plant 10002) could provide 90% or higher availability. The electricity generated by the PV plant 9502 and / or the wind farm 9402 can be directly supplied to the C&I customer 9802, or it can be stored in the LODES system 9404 first.

[0239] In some cases, the electricity supplied to C&I customer 9802 may come entirely from PV plant 9502, wind farm 9402, LODES system 9404, combined heat and power plant 10002, or any combination of PV plant 9502, wind farm 9402, LODES system 9404, and / or combined heat and power plant 10002. As an example, LODES system 9404 at power plant 10000 may have a duration of 24 hours to 500 hours. Specifically, the load on C&I customer 9802 may have a peak load of 100 MW, LODES system 9404 may have a rated capacity of 14 MW and a duration of 150 hours, the natural gas price may be $6 per million British thermal units (MMBTU), and the renewable share may be 58%. As another concrete example, the C&I customer 9802 can have a peak load of 100 MW, the LODES system 9404 can have a rated power of 25 MW and a duration of 150 h, the price of natural gas can be $8 / MMBTU, and the renewable share can be 65%.

[0240] Figure 101An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system combining one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 could include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 could be used to supplement nuclear power plant 10102 (or other inflexible power generation facilities, such as thermal power plants, biomass power plants, etc., and / or any other type of power plant with a ramp rate below 50% of rated power per hour and a high capacity factor of 80% or higher) to increase the flexibility of the combined output of power plant 10100, which consists of the combined LODES system 9404 and nuclear power plant 10102. Nuclear power plant 10102 can operate at a high capacity factor and peak efficiency point, while LODES system 9404 can be charged and discharged to effectively reshape the output of nuclear power plant 10102 to match customer electricity consumption and / or market electricity prices. As an example, the LODES system 9404 of power plant 10100 can have a duration of 24 hours to 500 hours. In a specific instance, nuclear power plant 10102 can have a rated output of 1,000 MW, and nuclear power plant 10102 may be forced into prolonged minimum stable power generation or even shutdown due to low electricity market prices. The LODES system 9404 can avoid facility shutdown and recharge during periods of low market prices; and subsequently, the LODES system 9404 can discharge and increase total output power generation when market prices inflate.

[0241] Figure 102An exemplary system is illustrated, in which one or more aspects of various embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of various embodiments could be a LODES system 9404. As an example, LODES system 9404 may include battery packs of various embodiments described herein, various electrodes described herein, etc. LODES system 9404 can operate in conjunction with SDES system 10202. Together, LODES system 9404 and SDES system 10202 can constitute power plant 10200. For example, LODES system 9404 and SDES system 10202 can be optimized together, allowing LODES system 9404 to provide various services, including long-term backup and / or bridging through multi-day fluctuations (e.g., multi-day fluctuations in market prices, renewable generation, electricity consumption, etc.), and SDES system 10202 to provide various services, including fast ancillary services (e.g., voltage control, frequency regulation, etc.) and / or bridging through intraday fluctuations (e.g., intraday fluctuations in market prices, renewable generation, electricity consumption, etc.). SDES system 10202 can have a duration of less than 10 hours and a round-trip efficiency of greater than 80%. LODES system 9404 can have a duration of 24 hours to 500 hours and a round-trip efficiency of greater than 40%. In one such example, LODES system 9404 can have a duration of 150 hours and support customer electricity consumption during renewable generation deficits for up to one week. LODES system 9404 can also support customer electricity consumption during intraday generation deficit events, supplementing the capacity of SDES system 10202. In addition, the SDES system 10202 can supply power to customers during periods of insufficient power generation during the day and provides high-quality services such as power regulation and voltage and frequency regulation.

[0242] The above description of the methods is provided only as exemplary embodiments and is not intended to require or imply that the steps of various embodiments must be performed in the presented order. As those skilled in the art will understand, the order of steps in the foregoing embodiments can be performed in any order. Words such as “after,” “then,” and “next” are not necessarily intended to limit the order of steps; these words are used to guide the reader through the description of the methods. Furthermore, any reference to an element of the claims in the singular form, such as the use of the articles “a,” “an,” or “the,” should not be construed as limiting the element to the singular.

[0243] Furthermore, any step of any embodiment described herein can be used in any other embodiment. The description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but is accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery pack, comprising: Oxygen reduction reaction (ORR) electrode; Oxygen evolution reaction (OER) electrode; Metal electrode; as well as An electrolyte, wherein the electrolyte separates the ORR electrode and the OER electrode from the metal electrode, wherein, The ORR electrode is immersed in the electrolyte. The ORR electrode comprises a series of separate ORR electrode components arranged vertically in a stack below the surface of the electrolyte, and Each separate ORR electrode component is adjusted to the different operating pressure that the respective component experiences at its depth in the electrolyte, and the pressure drop on each of the series of separate ORR electrode components arranged vertically in the stack is the same in the depth direction below the surface of the electrolyte.

2. The battery pack as claimed in claim 1, wherein, The ORR electrode and the OER electrode are separate electrodes.

3. The battery pack of claim 1, further comprising a stackable container supporting the ORR electrode, the OER electrode, the metal electrode, and the electrolyte.

4. The battery pack as claimed in claim 1, wherein, The ORR electrode is wavy or corrugated.

5. The battery pack as claimed in claim 1, wherein, The casing of the battery pack serves as a current conductor for the metal electrodes.

6. The battery pack as claimed in claim 2, wherein, The ORR electrode and the OER electrode are immersed in the electrolyte.

7. The battery pack as claimed in claim 6, wherein, The ORR electrode is supported in a frame that moves the electrolyte to create a gas volume at a depth below the surface of the electrolyte.

8. The battery pack as claimed in claim 6, wherein, The ORR electrode comprises an air-filled box-shaped configuration.

9. The battery pack as claimed in claim 6, wherein, The ORR electrode is supplied with air.

10. The battery pack of claim 9, wherein, The ORR electrode is bent.

11. The battery pack of claim 9, wherein, The ORR electrode is supported in a frame that traps the supplied air in an air chamber defined by the surface of the ORR electrode.

12. The battery pack of claim 9, wherein, The ORR electrode is tubular.

13. The battery pack as claimed in claim 2, wherein, The position of the metal electrode relative to the ORR electrode and the OER electrode is variable.

14. The battery pack as claimed in claim 1, wherein, The battery pack includes an airflow regulation structure.

15. The battery pack of claim 14, wherein, The airflow regulation structure includes an array of ramps in which holes are configured.

16. The battery pack of claim 1, wherein: The OER electrode and the ORR electrode are electrically separable, and the airflow to move the ORR electrode is flexed with or without the presence of the ORR electrode.

17. The battery pack of claim 1, wherein, The ORR electrode also includes a porous spacer.

18. The battery pack of claim 1, wherein, The metal electrode includes a direct reduction iron pellet bed.

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