Rotating electrochemical devices and methods of using the same

Abstract

An electrochemical device, including: a rotating assembly, including: a membrane electrode assembly (MEA) having an anode, a cathode, and a membrane disposed between the anode and the cathode and separating the anode from the cathode, and an outer casing located around the MEA; and a shaft coupled to the rotating assembly and configured to rotate the rotating assembly via rotation of the shaft, wherein the shaft extends through the rotating assembly and includes a first port formed therethrough, wherein the first port is at least part of a flow path configured to introduce liquid into the rotating assembly.

Description

[0001] ATTORNEY DOCKET 092119.0111 ROTATING ELECTROCHEMICAL DEVICES AND METHODS OF USING THE SAME CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No.63 / 676,289, filed July 26, 2024, the entire contents of which are hereby incorporated by reference as if fully set forth herein. BACKGROUND Electrochemical devices that provide multi-phase chemical synthesis are of increasing importance in today’s society. One example of multi-phase chemical synthesis is in the production of hydrogen via electrolysis, which involves applying electricity to split water into hydrogen and oxygen. This process is performed in an electrolyzer, which is an electrochemical device having an anode, a cathode, and a membrane (e.g., proton exchange membrane). An electrolyzer may receive water and electricity, perform an electrochemical reaction in which hydrogen ions move through the membrane from the anode to the cathode, and generate products of hydrogen gas and oxygen gas. Fuel cells are also of interest as power storage devices / power sources. Fuel cells have a similar structure to electrolyzers and essentially function in the reverse manner of electrolyzers. In particular, a fuel cell may receive a fuel (e.g., hydrogen gas) at the anode and air at the cathode, perform an electrochemical reaction in which protons move through the membrane from the anode to the cathode and electrons move through a circuit to generate electricity, and produce water as a by-product. ATTORNEY DOCKET 092119.0111 Advances in multi-phase chemical synthesis via electrochemical devices, such as electrolyzers and fuel cells, are being sought to improve the performance of these devices on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1A depicts an example rotating electrochemical device. FIG.1B depicts an example membrane electrode assembly (MEA) for use in the rotating electrochemical device of FIG.1A. FIG.2 depicts an example electrode for use in a rotating electrochemical device, showing an active area of the electrode. FIG.3 depicts an example system using a rotating electrolyzer to produce hydrogen. FIG.4 depicts an example system using a rotating fuel cell to generate electricity. FIG.5 depicts an example rotating electrochemical device with an electric power converter incorporate therein. FIG.6 depicts an example rotating electrolyzer using an inductive motor for both power and rotation. FIGS.7A and 7B depict an example passive pressure balancing system for a rotating electrochemical device. FIG.8 depicts an example system using at least one pressure regulator to control pressure in a rotating electrolyzer. FIGS.9-11 depict example computational fluid dynamics simulations illustrating the performance of different rotating electrolyzers under various operating conditions. FIG.12 depicts an example electrochemical device having a landscape oriented rectangular shaped electrode face. ATTORNEY DOCKET 092119.0111 FIG.13 depicts an example electrochemical device having a triangular shaped electrode face.

[0002] ATTORNEY DOCKET 092119.0111 DESCRIPTION OF EMBODIMENTS This application describes exemplary multi-phase electrochemical devices including electrolyzers and fuel cells that operate with improved efficiencies at high utilization rates. There are many subsets of hydrogen production equipment (e.g., electrolyzers) or hydrogen consumption equipment (e.g., fuel cells), but these can be generalized into two groups: high temperature equipment where everything going through the process is a gas (single-phase), and low temperature equipment where either the starting material (for an electrolyser) or the by product (for a fuel cell) is liquid (“multi-phase”). The present disclosure relates to these multi- phase, liquid-based devices. Although the following disclosure refers primarily to electrolyzers and fuel cells, it should be noted that similar techniques may be applied to any multi-phase electrochemical devices in which both liquid and gas are present. In liquid-based (i.e., multi-phase) electrolyzers and fuel cells, the membrane acts as a charge species transfer medium (e.g., salt bridge, proton exchange, or oxygen radial exchange membrane or barrier) that is species conductive, not electrically conductive. Electrons are communicated through an external circuit, and a narrow cell gap is required within the device to maintain low ohmic losses. In liquid-based hydrogen production and consumption devices, improvements in efficiency at a small scale (e.g., in the range of centimeters) do not translate to a large scale (e.g., in the range of meters). In addition, such liquid-based hydrogen production and consumption devices cannot be scaled to industrial size for a variety of reasons. For example, with a narrow cell gap, once an electrolyzer is switched on, every electrode element begins converting water into hydrogen (and OH-) at the cathode, and protons and oxygen gas at the anode. With a narrow cell gap, once a fuel cell is switched on, water vapor is produced at the cathode. The buoyancy of ATTORNEY DOCKET 092119.0111 bubbles is used as the transfer medium for the gas / vapor products in these processes. In electrolyzers that use buoyancy of bubbles as the transfer medium for gases, these products include hydrogen and oxygen gases that bubble up from the cathode and anode, respectively. In fuel cells, these products include the water vapor produced at the cathode. As time progresses and the gas flux remains constant, the products travel upward, exiting at the top of the cell. At steady state operation of an electrolyzer (and similarly for fuel cells), each portion of the cell at increasingly higher locations contains a greater amount of product bubbles that are moving upward out of the cell. Since these gas / vapor products are non- conductive, at increasing current densities (which produce directly proportional gas flux), the top part of the electrodes can become covered in nonconductive material, reducing the amount of electrical pathways. The movement of gas / vapor products blinds the anode and / or cathode surfaces, making the effective surface area of the electrode considerably smaller as a function of electrode height. As such, the real current density at the top and bottom of the cell are vastly different. Smaller lab-scale electrolyzers and fuel cells cannot be linearly scaled to industrial- scale devices, because as the cells are made larger, the available electrode surface area at the top of the cell becomes increasingly small. In addition, at higher utilization rates, electrolyzers and fuel cells become less efficient. This is because at high utilization rates, larger amounts of products are generated that can blind the top of the electrode surface, thus resulting in a failure to replenish the boundary layer with fresh electrolyte and a failure to remove the products that interfere with fresh material uptake. There have been advances in membrane structure in an attempt to improve the efficiency of electrolyzers and fuel cells. These membrane structures utilize a convoluted, three- dimensional interface structure with highly mixed media between the electrodes and the ATTORNEY DOCKET 092119.0111 membrane, effectively making the cell gap very small and the electrode surface area very high. Due to the transport mechanism (gravity and density difference driven buoyancy) and the change in state occurring at the electrode interface, the effective cell gap cannot be reduced enough to make up for increasingly larger sized electrodes. In addition, pore sizes in the interface structure can be too small, causing failure to replenish the interface with fresh electrolyte and failure to remove products that interfere with fresh material uptake. The advances in the membrane structure can provide some small scale improvement at low utilization rates. However, at the very large surface areas and high utilization rates that would be needed to operate an electrolyzer or fuel cell on an industrial scale, the membrane structure does not noticeably improve device performance. Generally, electrolyzers are run at lower current densities with efficiencies of 70% to 90%, but this translates to only between 10% and 30% utilization. At a certain point, the harder electrolyzers are pushed (e.g., by turning up the current), the less efficient they become. This inverse relationship between efficiency and utilization is a bottleneck in the electrolyzer portion of the hydrogen economy, because electrolyzers are not able to be scaled up to meet higher energy demands. At high utilization rates, an electrode surface area can never be large enough to compensate for gas production and its associated drop in performance, and the volume can never be large enough to accept and divert the gas produced. In addition, a large electrode surface area puts ever increasing demands on the limited and expensive catalyst resources. It is now recognized that a need exists for multi-phase electrochemical devices including electrolyzers and fuel cells that operate at higher efficiencies at high utilization rates. The inventors discovered rotating electrochemical devices that can be used to improve the efficiency of the device at high utilization rates and on an industrial scale. The rotating ATTORNEY DOCKET 092119.0111 electrochemical devices may be electrolyzers or fuel cells. The rotating electrochemical devices include at least an anode and cathode incorporated with a membrane together in a rotating membrane electrode assembly (MEA). Rotating the anode and cathode while pumping liquid (e.g., water) into the electrochemical device can cause the product bubbles to quickly migrate toward the center of the rotating anode / cathode surfaces for removal, instead of interfering with the uptake of reactants on the larger, active portion of the electrode. As a result, the rotating electrochemical devices are able to operate at higher efficiencies at high utilization rates, as compared to devices with stationary electrodes. The inventors also discovered ways to more efficiently operate rotating electrochemical devices using an inductive coupling, removing the need for carbon brushes and thereby reducing drag, spark, and CO2 risk while improving service life of the device. The inventors also discovered ways to control pressure(s) within rotating electrochemical devices to improve performance at high utilization rates. The inventors also discovered that changing a shape of the electrodes in the electrochemical devices can improve the efficiency of the electrochemical device at high utilization rates. The shapes of electrodes discussed herein may reduce the total amount of gas bubbles that are produced at the electrode while maintaining a desired surface area of the electrode. FIG.1A depicts an example rotating electrochemical device 100 having rotating components. The electrochemical device 100 may take advantage of a modern MEA and stack design. The use of an MEA improves efficiency of the electrochemical device 100 in general, and the rotation of the MEA further improves performance of the electrochemical device 100. ATTORNEY DOCKET 092119.0111 The electrochemical device 100 comprises a rotating assembly 102 coupled to a shaft 104. The rotating assembly 100 may include at least one MEA 106. In the illustrated embodiment, the rotating assembly 102 includes a plurality of MEAs 106 interposed between a plurality of bipolar plates 108. Each MEA 106 includes an anode, a cathode, and a membrane disposed between the anode and cathode. The rotating assembly 102 also includes an outer casing 110 located around the MEA(s) 106. The shaft 104 is coupled to the rotating assembly 102 and configured to rotate the rotating assembly 102 via rotation of the shaft 104. As such, all components of the at least one MEA 106 (e.g., anode, cathode, and membrane) may be rotated, via the rotating shaft 104, in the same direction and at the same speed during operation of the electrochemical device 100. It should be noted that the shaft 104 may include multiple coaxial shafts that are coupled together and rotate together. The rotating assembly 102 having one or more MEAs 106 may be rotated during operation of the electrochemical device 100. That is, the electrochemical device 100 may receive input energy and perform an electrochemical reaction via the MEAs 106 while the MEAs 106 are rotating. The electrochemical device 100 may output at least one product generated by the electrochemical reaction. In one example, the electrochemical device 100 is an electrolyzer. The electrolyzer receives electrical energy and a reactant (e.g., water) input thereto. The products generated from the electrochemical reaction in the electrolyzer may be hydrogen (e.g., H2 gas) and oxygen (e.g., O2gas). In an electrolyzer, oxygen is generated at the anode(s) and hydrogen is generated at the cathode(s). The hydrogen generated by the electrolyzer may be used as a power source for other operations. The electrolyzer may receive electrical energy from renewable energy source(s) so as to provide a clean source of hydrogen with low or no carbon emissions. ATTORNEY DOCKET 092119.0111 In another example, the electrochemical device 100 is a fuel cell. The fuel cell receives a fuel (e.g., hydrogen) and a reactant (e.g., air, O2, etc.) input thereto. The electrochemical reaction in the fuel cell generates electricity, and a product generated from the electrochemical reaction in the fuel cell may be water (e.g., H2O vapor). In a fuel cell, the water vapor is generated at the cathode(s). The fuel cell may be used as a low-emission power source to generate electricity for powering other operations. Even though electrolyzers and fuel cells have different functions, they each may include similar components (e.g., MEAs). In addition, both electrolyzers and fuel cells may benefit in similar ways from the rotation of the MEAs as disclosed herein. Certain products of the electrochemical device 100 produced at the anode(s) and the cathode(s) may take the form of gas bubbles (e.g., hydrogen and oxygen in an electrolyzer, or water vapor in a fuel cell). These gas bubbles can block the surface area of the electrodes (i.e., anode(s) and / or cathode(s)) and interfere with the uptake of reactants along the anode(s) and / or cathode(s) where they are produced. In the electrochemical device 100, the rotating assembly 102 having MEAs 106 may cause at least one product (e.g., gas bubbles) generated from the electrochemical reaction to radially shear toward the center of rotation, thus reducing the amount of product that might otherwise interfere with uptake of reactants. This may increase the efficiency of the electrochemical reaction for the rotating electrochemical device 100, particularly at high utilization rates, compared to an electrochemical device without rotating components. The speed of rotation of the rotating assembly 102 may be varied based on an amount of energy input to the electrochemical device 100 and an amount of the product being output (for electrolyzers) or electricity being generated (for fuel cells) from the electrochemical device 100. ATTORNEY DOCKET 092119.0111 The cylindrical shaped rotating assembly 102 may be relatively easy to model for determining a shear rate. The shear rate will be consistent across the outer face of the cylinder and can be calculated simply based on the radius of the rotating assembly 102. FIG.1B schematically depicts a cross-section of a single MEA 106 of the rotating assembly (102 of FIG.1A) as viewed from a direction perpendicular to a longitudinal axis of the shaft 104. Each MEA 106 in the rotating assembly 102 of FIG.1A may have the same structure. As shown in FIG.1B, the MEA 106 includes an anode 112, a cathode 114, and a membrane 116 disposed between the anode 112 and cathode 114 and separating the anode 112 from the cathode 114. In each MEA 106, the anode 112 and cathode 114 may be disk shaped. The membrane 116 may be at least partially integrated with the anode 112 on one side and with the cathode 114 on an opposite side. As shown in FIG.1A, the plurality of MEAs 106 and plurality of bipolar plates 108 stacked with respect to each other form a plurality of chambers 118 within the rotating assembly 102, with each chamber 118 having an anode (112 of FIG.1B) or a cathode (114 of FIG.1B) located therein. In the illustrated embodiment, an end anode 112A is located at one end of the stack of MEAs 106 and bipolar plates 108, and an end cathode 114A is located at the opposite end of the stack. As illustrated, the rotating assembly 102 includes the outer casing 110 located around the stack of MEAs 106 (including the end anode 112A and end cathode 114A) and bipolar plates 108. The outer casing 110 may seal the rotating assembly 102, in particular sealing each of the chambers 118 in the rotating assembly 102. In an embodiment, the shaft 104 extends through the rotating assembly 102 and includes a first port 120 formed therethrough. The first port 120 is at least part of a flow path configured to introduce liquid (e.g., water) into the rotating assembly 102. The liquid may be fed via the first ATTORNEY DOCKET 092119.0111 port 120 (acting as a manifold) into the plurality of chambers 118 in the rotating assembly 102 from the center of the rotating assembly 102, proximate the rotational axis. Due to the rotation of the rotating assembly 102, the higher density liquid being introduced into the chambers 118 is driven radially outward from the center of the rotating assembly 102 by centrifugal force. This keeps the liquid in contact with an active portion of the MEAs 106, preventing the MEAs 106 from drying out and forcing gas products toward the center. The shaft 104 may also include a second port 122 formed therethrough. The second port 122 may be at least part of a second flow path configured to retrieve a first gas product of an electrochemical reaction in the rotating assembly and transport the first gas product to a first outlet (not shown) outside the rotating assembly 102. The first gas may be retrieved to the center of the rotating assembly 102 via the second port 122 (acting as a collection manifold) from the chambers 118 having cathodes. In embodiments where multiple gases are produced at the electrodes, the shaft 104 may also include a third port 124 formed therethrough. The third port 124 may be at least part of a third flow path configured to retrieve a second gas product of the electrochemical reaction in the rotating assembly and transport the second gas product to a second outlet (not shown) outside the rotating assembly 102. The second gas may be retrieved to the center of the rotating assembly 102 via the third port 124 (acting as a collection manifold) from the chambers 118 having anodes. The second flow path (e.g., including the second port 122) may be entirely separated from the third flow path (e.g., including the third port 124) so as to keep the gas products from mixing. For example, the second port 122 may be ported to the chamber(s) 118 on the cathode side of each MEA 106 and the third port 124 may be ported to the chamber(s) 118 on the anode side of each MEA 106. The first port 120 used to introduce fluid into the chambers 118 may be ATTORNEY DOCKET 092119.0111 ported to each chamber 118. As discussed below with reference to FIG.8, in some embodiments, the second and third ports 122 and 124 may be fluidly coupled to at least one pressure regulator at a position downstream of the second port 122 and the third port 124. FIG.2 schematically depicts an electrode 200 (e.g., anode and / or cathode) of the rotating assembly of FIG.1 surrounding the shaft 104. As discussed above, the rotating assembly (e.g., 102 of FIG.1) may be sealed by the outer casing (e.g., 110 of FIG.1). As described above, the sealed device is fed liquid from the central shaft 104 and retrieves separated gases (gas products) via the same shaft 104. On anything that rotates, the centripetal acceleration is a function of the radius and rotational velocity (rpm). As a fixed disk experiences the same rotational velocity, only radius dictates the acceleration. Acceleration is highest the larger the radius, and this means that the acceleration is lowest closest to the axis of rotation. The key to operating such a device for electrolysis is keeping liquid (e.g., water) introduced by the shaft 104 between the outer rim 202 (R1) and some other radius 204 (R2) closer to the center to maintain similar acceleration and therefore pressure. The high rotation speed of the rotating assembly ensures all or nearly all of the water is pushed radially outward (arrow 206) towards the outer rim 202, meaning there will be practically no water entrainment in the gas streams moving radially inward (arrow 208) towards the shaft 104. This removes the need for an additional separation step downstream of the gas outlet(s). As shown in FIG.2, the active area 210 of the electrode 200 is located between the outer rim 202 and the radius 204 closer to the center. This active area 210 is where all of, or the bulk of, the electrochemical reaction takes place on the electrode 200. Rotating the electrochemical device of FIG.1A causes the liquid to move, via acceleration from the rotating assembly, to active areas 210 along the anode and the cathode where the electrochemical ATTORNEY DOCKET 092119.0111 reaction is performed. The are of the electrode 200 located radially between the radius 204 and the shaft 104 may be electrochemically inactive. Without rotating the electrode that is fed liquid from the central shaft, there is dead liquid in the center. Instead, because of the rotation of the electrode 200 the head pressure of the liquid pushes radially outward, increases the acceleration field, and provides the density difference needed for the gas product bubbles to move radially to the center of the electrode surface. Instead of trying to produce an electrochemical reaction on the entire surface of the electrode 200, the rotating electrochemical device may be operated to optimize the radial distance 206 between R1 and R2 for performance. It should be noted that the previous residence time and accumulation limits (for gas products) still exist in rotational electrochemical devices. Like their static cousins, they do not scale. There will be some optimized radial distance 212 between R1 and R2 that is determinable. Smaller output devices would have this same radial distance 212 but need higher rotational speeds and a smaller foot print to achieve the same relative acceleration field. Larger devices would have the same distance 212 between R1 and R2, but the radiuses R1 and R2 will be considerably larger, the rotation speed much slower, and the surface area (an R2term) much larger. For instance, a 20 cm radius requires about 1000 rmp to generate 200 g, whereas a 1 m radius requires 415 rpm to generate the same acceleration field. However, the surface area of a 1 m to .9 m ring (radial distance 212 between R1 and R2 =.1 m) is six times larger than a 20 cm to 10 cm ring. If the radial distance 212 between R1 and R2 is 20 cm, and we consider a 1 m radius circle and a 20 cm radius circle, the active surface area (210) located between 1 m (202) and .8 m (204) is 10 times larger than the active surface area (210) located between 20 cm (202) and 0 cm (204). In this respect, there are considerable advantages to larger radius devices. ATTORNEY DOCKET 092119.0111 The rotation speed, pressure, and current density of the electrochemical device may be maximized to maintain a high degree of liquid phase where the electrodes 200 are active (210). The radial shear force and high pressure and acceleration field may work together to maximize electrode active surface area 210 at maximum current density, thereby maximizing both catalyst usage and utilization rate. Such a rotating electrochemical device 100 as described above with reference to FIGS. 1A-2, using one or more modern MEAs 106, may provide increased operational efficiency particularly for larger devices. Liquid (e.g., water) can be driven in, squeezing gas out, thereby taking full advantage of the exaggerated density difference that comes with a higher acceleration field. Turning again to FIG.1A, the shaft 104 may have other ports or communication paths formed therethrough as well. For example, a wire 126 may extend through a fourth port 128 formed through the shaft 104. The wire 126 may be electrically coupled to an anode or a cathode in the rotating assembly 102. For example, the wire 126 may extend to and be attached to the end anode 112A of the rotating assembly 102. This wire 126 may be electrically coupled (via the MEA stack) to another wire (not shown) that is attached to the end cathode 114A, forming a circuit. In some embodiments, DC current may be applied to the circuit to cause the electrochemical reaction in the MEA stack. As such, the fourth port 128 may be used for power delivery to a far electrode. In other embodiments such as fuel cells, the electrochemical reaction in the MEA stack may cause DC current to flow through the circuit. In an embodiment, at least one wired communication path 130 may extend through at least one port formed through the shaft 104. As shown, the wired communication path 130 may extend through a port (e.g., fourth port 126) that is being used for another purpose (e.g., power ATTORNEY DOCKET 092119.0111 delivery). Alternatively, the wired communication path(s) 130 may extend through their own one or more dedicated ports (e.g., a fifth port) through the shaft 104. The wired communication path(s) 130 may be used for data collection from one or more sensors located in the chambers 118 or in fluid communication with the chambers 118 (e.g., to monitor pressure, oxidation reduction potential (ORP), pH, reference electrode measurements, flow rates, or other parameters). It should be noted that the shaft 104 may include multiple coaxial shafts that are coupled together, end to end, and ported with sealed connections to facilitate the desired communication of liquid, gases, and / or electrical communication through the shaft 104. FIGS.3 and 4 depict systems in which the electrochemical device 100 of FIG.1A may be used. FIG.3 depicts a system 300 having a rotating electrolyzer 302, which may have a structure similar to the above-described electrochemical device. As shown in FIG.3, the rotating electrolyzer 302 receives electricity from an electricity source 304 and water from a water source 306 and produces hydrogen gas 308 and oxygen gas 310 at different outlets. The hydrogen gas 308 may be directed to a load 312, for example, as a fuel source to power one or more downstream processes. The system 300 also includes at least one motor 314 configured to rotate at least one shaft 316 of the electrolyzer 302, thereby rotating the at least one MEA of the electrolyzer 302 as described above. In some embodiments, the electricity source 304 may be a highly volatile energy input, such as electricity generated from renewable sources (e.g., solar, wind, geothermal, tidal, etc.). As such, there may be a non-linear interest in the efficiency of the electrolyzer 302 since it may be run at higher and lower utilization rates over time. ATTORNEY DOCKET 092119.0111 The system 300 may include a controller 318 communicatively coupled to the at least one motor 314 and configured to control a rotational speed of the motor(s) 314 based on feedback regarding an amount of energy input to the electrolyzer 302 (e.g., from electricity source 304) and an amount of product (e.g., hydrogen 308) to be output from the electrolyzer 302. For example, modulating the speed of the motor(s) 314 based on the current from the electricity source 304 may allow the rotating electrolyzer 302 to shear more gas bubbles as the current increases, so the system 300 operates at higher efficiencies even at high utilization rates. The controller 318 may be a hardware device or a hardware and software device configured to control and / or communicate with the electricity source 304, the load 312, and / or the motor 314 according to certain embodiments. As a hardware device, the controller 318 may include circuitry configured to receive and / or transmit signals to the electricity source 304, the load 312, and / or the motor 314. As a hardware and software device, the controller 318 may include a processor or a microcontroller coupled to memory storing software (e.g., executable instructions), such that when the processor or the microcontroller executes the software, the controller 318 may receive and / or transmit signals to the electricity source 304, the load 312, and / or the motor 314. FIG.4 depicts a system 400 having a rotating fuel cell 402, which may have a structure similar to the above-described electrochemical device of FIGS.1A-2. As shown in FIG.4, the rotating fuel cell 402 receives energy from a fuel source 404 (e.g., hydrogen) and air and generates electricity 406 while producing water 408 (e.g., water vapor) as a by-product. The generated electricity 406 may be directed to a load 410, for example, powering one or more processes. The system 400 also includes at least one motor 412 configured to rotate at least one ATTORNEY DOCKET 092119.0111 shaft 414 of the fuel cell 402, thereby rotating the at least one MEA of the fuel cell 402 as described above. The system 400 may include a controller 416 communicatively coupled to the at least one motor 412 and configured to control a rotational speed of the motor(s) 412 based on feedback regarding an amount of energy input to the fuel cell 402 (e.g., from fuel source 404) and an amount of electricity 406 to be generated by the fuel cell 402. For example, modulating the speed of the motor(s) 412 based on the current needed from the fuel cell 402 may allow the rotating fuel cell 402 to shear more gas bubbles as the current increases, so that the system 400 operates at higher efficiencies even at high utilization rates. The controller 416 may be a hardware device or a hardware and software device configured to control and / or communicate with the fuel source 404, the load 410, and / or the motor 412 according to certain embodiments. As a hardware device, the controller 416 may be circuitry configured to receive and / or transmit signals to the fuel source 404, the load 410, and / or the motor 412. As a hardware and software device, the controller 416 may include a processor or a microcontroller coupled to memory storing software (e.g., executable instructions), such that when the processor or the microcontroller executes the software, the controller 416 may receive and / or transmit signals to the fuel source 404, the load 410, and / or the motor 412. FIG.5 illustrates an embodiment of a rotating electrochemical device 500 that includes an inductive coupling and has power and conditioning onboard the rotating device. The rotating electrochemical device 500 includes a rotating assembly 502 and a shaft 504 coupled to the rotating assembly 502 and configured to rotate the rotating assembly 502. The rotating assembly 502 is illustrated schematically and, similar to the rotating assemblies described above with reference to FIGS.1A and 1B, comprises: at least one MEA having an anode, a cathode, and a ATTORNEY DOCKET 092119.0111 membrane disposed between the anode and the cathode and separating the anode from the cathode; and an outer casing located around the MEA. In terms of power communication, the rotating electrochemical device 500 generally includes an electric power converter 506, an inductive coil 508, and a power communication wire 510. The power communication wire (“wire”) 510 extends at least partially through the shaft 504 and is coupled to an anode or a cathode in the rotating assembly 502. Similar to the wire 126 of FIG.1A, the wire 510 may extend to and be attached to an end anode (or cathode) of the rotating assembly 502. This wire 510 may be electrically coupled (via the MEA stack) to another wire (not shown) that is attached to an opposite end cathode (or anode), forming a circuit. In an embodiment, current is applied to the circuit to cause the electrochemical reaction in the MEA stack. As such, the wire 510 may be used for power delivery to a far electrode. In another embodiment, the electrochemical reaction in the MEA stack causes a current to flow through the wire 510. The electric power converter 506, as schematically illustrated, may be disposed in or along the rotating assembly 502 (e.g., forming part of the rotating assembly). In other embodiments, the electric power converter 506 may be disposed in or along the shaft 504. In either case, the electric power converter 506 is a rotating feature of the rotating electrochemical device 500. As shown, the electric power converter 506 is coupled to the wire 510 and is configured to output DC current to the wire 510 or to receive DC current from the wire 510. The electric power converter 506 may include an AC / DC converter or a DC / AC converter. The electric power converter 506 may be as simple as a diode bridge depending on the number of AC phases used, or may be a more complicated potentiostat / galvanostat. ATTORNEY DOCKET 092119.0111 The inductive coil 508 is disposed in or along the shaft 504 and coupled to the electric power converter 506 (e.g., via a wired connection 512). The inductive coil 508 communicates AC power between the rotating components and a non-rotating external power source or load. Using the inductive coil 508 for power communication in the rotating electrochemical device 500 enables operation of the rotating electrochemical device 500 without causing drag or forming sparks, since no direct contact is made between the rotating inductive coil 508 and the non-rotating portion of the inductive coupling. The inductive coupling also would not be subject to fatigue loading during use like other rotating / non-rotating methods of power communication (e.g., carbon brushes, slip rings, etc.). In addition, using the inductive coil 508 and the electric power converter 506 within the rotating parts of the electrochemical device 500 means that none of the wires would be exposed. In embodiments where the electrochemical device 500 is an electrolyzer, the inductive coil 508 may be configured to receive AC power from a non-rotating power source located outside the electrochemical device 500 and to provide at least a portion of that AC power to the electric power converter 506. As such, the electric power converter 506 is an AC / DC converter configured to output DC current to the wire 510 for supplying power to the MEA(s) of the rotating assembly 502, and the inductive coil 508 is configured to provide AC current to the AC / DC converter (506). In embodiments where the electrochemical device 500 is a fuel cell, the inductive coil 508 may be configured to receive AC power from the electric power converter 506 and to output at least a portion of that AC power from the electrochemical device 500, for example, to power a load located outside the electrochemical device 500. As such, the electric power converter 506 is ATTORNEY DOCKET 092119.0111 a DC / AC converter configured to receive DC current from the wire 510, and the inductive coil 508 is configured to output AC power from the electrochemical device 500. One or more sensors 514 may be located within the rotating assembly 502 or the shaft 504 (e.g., inside one or more ports in the shaft 504) and used to collect reference electrode measurements, pressure readings, flow rates, ORP, and / or pH measurements from one or more locations within the rotating assembly 502. The sensor(s) 514 may be coupled via wiring within the rotating assembly 502 and / or the shaft 504 to a wireless communication interface 516. The wireless communication interface 516 may be used to communicate the sensor signals to an external control system via a wireless protocol (e.g., Bluetooth, Wi-Fi, or other radio transmission protocol). Using a wireless communication interface 516 in this manner, as opposed to slip rings or external cabling, may enable real-time capture of sensor measurements without causing drag or risking a spark near the electrochemical device 500. The electric power converter 506, inductive coil 508, and associated connections described with reference to FIG.5 may be used in the rotating electrochemical device 100 of FIG.1A. In certain embodiments, the inductive coil may form part of an inductive motor used to rotate the rotating assembly. For example, FIG.6 illustrates a rotating electrolyzer 600 having an inductive motor. The rotating electrolyzer 600 includes a rotating assembly 602 rotatable by a shaft 604. The rotating assembly 602 and / or shaft 604 may take the form of those described above with reference to FIG.1A. For example, the rotating assembly 602 includes one or more MEAs, and the shaft 604 may include ports for communicating one or more liquids, gases, power, and / or electrical signals. The rotating electrolyzer 600 includes an AC / DC power ATTORNEY DOCKET 092119.0111 converter 606, which may operate as the electric power converter described above with reference to FIG.5 in the “electrolyzer” embodiment. The rotating electrolyzer 600 also includes the inductive motor 608, which includes an inductive coil disposed in or along the shaft 604. The inductive motor 608 may provide mechanical power to rotate the shaft 604 (and the rotating assembly 602) while also providing AC power (arrow 610) to the AC / DC converter 606 for powering the electrolysis operation in the rotating assembly 602. For example, a portion of the AC current being induced in the inductive coil of the induction motor 608 is output to the AC / DC converter 606 (e.g., via a feed taken off the inductive coil), and the rest of the AC current in the inductive coil is used to rotate the shaft. Most of the AC current induced in the inductive coil may contribute to the electrolysis operation while a smaller fraction of the AC current contributes to rotation of the assembly 602. This arrangement may simplify construction of the rotating electrolyzer 600 while providing all the benefits of using an inductive coupling to power the electrolyzer 600. In a rotating electrochemical device having one or more MEAs, it may be desirable to regulate the pressure within the different chambers of the rotating assembly. In certain embodiments, a passive pressure balancing system may be used to balance pressure between opposing sides of the membrane of an MEA. For example, FIGS.7A and 7B illustrate a passive pressure balancing system 700. FIG.7A is a schematic illustration showing one disk-shaped MEA 702 located around a shaft 703. The MEA 702 shown and described with reference to FIGS.7A and 7B may be used in a rotating electrochemical device as described above with reference to FIGS.1A and 1B. The outer casing of the rotating assembly is not shown in FIGS. 7A and 7B for simplicity of illustration. ATTORNEY DOCKET 092119.0111 The MEA 702 comprises an anode 704, a cathode 706, and a membrane 708 disposed between the anode 704 and the cathode 706 and separating the anode 704 from the cathode 706. As illustrated, the anode 704 may include an inactive portion 710 located thereon and the cathode 706 may include an inactive portion 712 located thereon. The inactive portions 710 and 712 are electrochemically inactive. The inactive portion 710 of the anode 704 is located at a same circumferential position and at a same radial position with respect to a rotational axis 714 of the MEA 702 as the inactive portion 712 of the cathode 706. In addition, an orifice 718 is formed in the membrane 708 at a location corresponding to the same circumferential position and the same radial position with respect to the rotational axis 714 of the MEA 702 as the inactive portions 710, 712 of the anode 704 and the cathode 706. The orifice 718 functions as a very small flow path between the two sides of the MEA 702 to balance pressure between a first chamber (e.g., 118 of FIG.1A) having the anode 704 on a first side of the membrane 708 and a second chamber (e.g., 118 of FIG.1A) having the cathode 706 on a second side of the membrane 708. The orifice 718 may keep the pressure on both sides of the MEA 702 substantially or entirely pressure balanced so that the rotating electrochemical device is isobaric. This pressure balance prevents large pressure differentials from forming between the two sides of the MEA 702 that might otherwise threaten to rupture the delicate MEA 702. As illustrated, the inactive portions 710, 712 of the anode 704 and the cathode 706 and the orifice 718 through the membrane 708 are located proximate the outer rim 720 (R1) of the MEA 702, outside of the radius 722 (R2) defining the active portions of the electrodes (similar to the R1 and R2 described above with reference to FIG.2). Due to the presence of inactive portions 710, 712, no electrolysis or electrical shorts would happen at this location ATTORNEY DOCKET 092119.0111 (corresponding to the orifice 718) of the electrodes (704, 706). In addition, the presence of liquid (e.g., water) in this area of the chambers may prevent mixing of any hydrogen and oxygen produced at the surrounding active portions of the electrodes (704, 706). In other embodiments, as shown in FIG.8, an active pressure regulation system may be used to balance pressure within the rotating electrochemical device. FIG.8 is a schematic illustration showing a system 800 having a rotating electrolyzer 802, which may have a structure similar to any electrochemical device described above (e.g., FIGS.1A-3 and 5-7B). As discussed above with reference to FIG.3, the rotating electrolyzer 802 receives electricity from an electricity source 804 and water from a water source 806 and produces hydrogen gas 808 and oxygen gas 810 at different outlets. The system 800 also includes at least one motor 812 configured to rotate at least one shaft 814 of the electrolyzer 802, thereby rotating the at least one MEA of the electrolyzer 802 as described above with reference to FIG.1A. The system 800 also includes at least one pressure regulator 816 at the outlets for the hydrogen gas 808 and oxygen gas 810. For example, the rotating electrolyzer 802 may have the structure shown in FIG.1A with a second port through the shaft for communicating hydrogen gas and a third port through the shaft for communicating oxygen gas. The at least one pressure regulator 816 may be coupled to the second port and / or the third port at a position downstream of the second port and / or the third port. A single pressure regulator 816 may be used to control the output pressure of both hydrogen gas 808 and oxygen gas 810, as shown, allowing pressure balance without mixing the streams. In another embodiment, two pressure regulators that are in perfect or near perfect calibration and unison may be used to control the output pressure of the two gas feeds to balance the pressure. ATTORNEY DOCKET 092119.0111 It may be desirable to control the gas feeds to operate at high pressures via the at least one pressure regulator 816. Combined with the high acceleration field of the rotating electrolyzer 802, the pressure regulator(s) 816 may ensure that both gas output streams (808 and 810) are of usably high pressure, compressed, and very dry. This may allow the system 800 to output the gas streams without an additional dewatering step in the process, making downstream compression steps considerably less expensive. In addition, using the pressure regulator 816 to output the gas streams at high pressures may reduce or minimize the surface area of the gas phase within the liquid phase inside the electrolyzer 802 during its operation. This offers significant improvements in electrolysis performance since the gas can be removed more quickly from the electrolyzer 802, allowing sufficient reactant uptake along a larger portion of the electrodes. Using the pressure regulator(s) 816 allows much higher output pressures of gas to be achieved while also maintaining the same pressure on both sides of the MEAs within the electrolyzer 802, preventing MEA rupture. FIGS.9-11 depict example simulations demonstrating the performance of different rotating electrolyzers under varying conditions. Using computational fluid dynamics to simulate electrolyzers can be difficult. However, ignoring the electrochemistry and focusing on bubble production from a single face while having an exit at one end is a good surrogate for modeling the electrolyzers. FIGS.9-11 present graphical data of gas volume fraction along slices of a rotating electrolyzer modeled as a bubbler, showing the increased performance and the phases in higher acceleration fields. FIG.9 illustrates the volume fraction of gas to liquid for a 10 cm tall electrolyzer at 1g acceleration field and 6x10-5kg / s / m2mass flow rate. FIG.10 illustrates the volume fraction of gas to liquid for a 1 m tall electrolyzer at the same acceleration field (1g) and mass flow rate ATTORNEY DOCKET 092119.0111 6x10-5kg / s / m2). FIG.11 illustrates the volume fraction of gas to liquid for a 1 m tall electrolyzer at a larger acceleration field (50g), higher mass flow rate (.001 kg / s / m2), and a backpressure 42 psi (3 atmospheres). As can be seen by comparing FIGS.9 and 10, electrolyzers do not scale according to the model using a gas bubbler for an electrolysis surrogate. In particular, the performance of the modeled “electrolyzer” shows that for a larger electrolyzer (FIG.10), only the very ends of the slices have a high volume fraction of gas bubbles, indicating reduced performance in proportion to the smaller electrolyzer (FIG.9). In FIG.11, the modeled “electrolyzer” shows that an acceleration field of 50g with a back pressure of 42 psi generates a clear image of where the liquid remains liquid (small volume fraction of gas bubbles). This is the point where the active portion of the electrodes (e.g., as in the active portion 210 shown in FIG.2) should stop for a rotating electrolyzer operating under these conditions. Note that the gas flux generated in FIG.11 is 16 times more, or one and a half magnitudes more, than in FIG.10, indicating enhanced performance of the electrolyzer. Other techniques for improving the efficiencies of electrochemical devices (e.g., electrolyzers and fuel cells) at high utilization rates include adjusting a shape of the electrodes (i.e., anodes and cathodes) used in the electrochemical device, so that a smaller portion of the surface area of the electrode is negatively impacted by the rising gas bubbles produced in the electrochemical reaction. Existing electrochemical devices are rectangular for many reasons, but one of the most prominent is the ease in calculating the area specific current density, as the area is length times height. Additionally, ease of manufacture, high packing density, and ease of manifolding are other reasons for the rectangular approach. Electrochemical devices are typically oriented in “portrait” mode (i.e., having a vertical height that is greater than the width) as a ATTORNEY DOCKET 092119.0111 legacy from electrochemical devices where continuous pumping is needed and there is no change of state from liquid to gas. FIGS.12 and 13 schematically depict example electrochemical devices (in cross section) with electrode faces shaped to improve the efficiency of the electrochemical device. FIGS.12 and 13 each depict an electrochemical device (1200, 1300) having a housing (1202, 1302) and an electrode (e.g., anode, cathode) (1204, 1304) located in the housing (1202, 1302). The electrode (1204, 1304) represents the shape of each anode and cathode located and / or stacked within the housing (1202, 1302). Similar to the embodiments discussed above, the electrochemical device (1200, 1300) includes a membrane (not shown) located between a pair of electrodes (1204, 1304) (anode and cathode) in the housing (1202, 1302). The electrochemical device (1200, 1300) may be an electrolyzer or a fuel cell. For electrochemical processing devices that have a change of state from liquid to gas, or even liquid to particle sinking solid, being subject to Earth’s gravitational field means that a single order of magnitude change in height of the electrode greatly affects the efficiency of the electrochemical process. However, changes in horizontal size of the electrode do not affect the efficiency of the electrochemical process for a given per unit width mass flow rate. FIG.12 depicts an electrochemical device 1200 having an electrode 1204 that is placed in “landscape” mode instead of “portrait” mode so that fewer products of the electrochemical reaction may interfere with the uptake of reactant on the electrode 1204. As shown in FIG.12, the housing 1202 includes a top surface 1206 and a bottom surface 1208, and the electrochemical device 1200 is configured to be supported on the bottom surface 1208 of the housing 1202. The electrode 1204 has a rectangular shape defined by upper and lower edges 1210 and 1212 and two side edges 1214 and 1216 connecting the upper and lower edges 1210 and 1212, the upper edge ATTORNEY DOCKET 092119.0111 1210 being located proximate the top surface 1206 of the housing 1202 and the lower edge 1212 being located proximate the bottom surface 1208 of the housing 1202. When viewed in the direction perpendicular to the plane of the electrode 1204, the upper and lower edges 1210 and 1212 have a greater length than the two side edges 1214 and 1216. The upper and lower edges 1210 and 1212 may be oriented in a horizontal direction while the two side edges 1214 and 1216 may be oriented in a vertical direction when the electrochemical device 1200 is supported on the bottom surface 1208 of the housing 1202. Using electrodes 1204 with a reduced vertical height in the electrochemical device 1200, as shown in FIG.12, may reduce the amount of gas bubbles interfering with reactant uptake on the electrodes 1204. This allows the electrochemical device 1200 to operate at higher efficiencies at high utilization rates compared to electrochemical devices having the same electrode surface area and a greater height. FIG.13 depicts an electrochemical device 1300 having an electrode 1304 that has a non- rectangular shape (e.g., a triangular shape) so that a greater amount of the electrode 1304 operates at a higher performance. As shown in FIG.13, the housing 1302 includes a top surface 1306 and a bottom surface 1308, and the electrochemical device 1300 is configured to be supported on the bottom surface 1308 of the housing 1302. When viewed in the direction perpendicular to the plane of the electrode 1304, the electrode 1304 has a triangular shape defined by an upper edge 1310 and two side edges 1312 and 1314 connected to opposite ends of the upper edge 1310, with the upper edge 1310 being located proximate the top surface 1306 of the housing 1302. The upper edge 1310 may be oriented in a horizontal direction when the electrochemical device is supported on the bottom surface 1308 of the housing 1302. ATTORNEY DOCKET 092119.0111 The two side edges 1312 and 1314 in FIG.13 function as “lower” edge(s) of the electrode 1304. Regardless of the shape of the electrochemical device 1300, electrochemical performance will be maximized along the “lower” edge(s), that is, edges of the electrode that have no portions of electrode located below them. This is because at the “lower” edge(s), the electrode 1304 has no bubbles that are coming up from below to interfere with electrochemical performance. As such, electrode shapes that maximize the length of the “lower” edge(s) (e.g., 1312 and 1314) of the electrode 1304 may have improved performance compared to those with shorter lengths of the “lower” edge(s). In addition, the inverted triangle shape of the electrode 1304 in FIG.13 has a larger upper portion of the electrode 1304 to compensate for the expansion that occurs due to the phase change from liquid to gas. In the electrochemical device 1300 of FIG.13, the highest proportion of gas flow will be up the center. The triangle shape of the electrode 1304 provides fresh electrode surfaces as the “lower” edge(s) where performance is the greatest is now two slopes (side edges 1312 and 1314) on either side of the center. The increase in surface area and volume as a function of increasing height compensates for the increased gas concentration. Other non-rectangular shapes may be used for the electrode 1304 as well. The non- rectangular shape of the electrode 1304, when viewed in a direction perpendicular to the plane of the electrode 1304, may be any shape that has a geometric centroid located closer to the top surface 1306 of the housing 1302 than to the bottom surface 1308 of the housing 1302. Although the housing 1302 in FIG.13 is shown as having a rectangular cross-section, in other embodiments the housing 1302 may have a similar cross-section as that of the electrode 1304 (e.g., triangular or otherwise). ATTORNEY DOCKET 092119.0111 Using electrodes 1304 with a reduced amount of surface area toward the bottom of the electrode 1304 than toward the top of the electrode 1304, as shown in FIG.13, may provide greater lengths of the “lower” edge(s) having the best performance while providing space toward the top of the electrodes 1304 for expansion of bubbles coming from below. This allows the electrochemical device 1300 to operate at higher efficiencies at high utilization rates compared to electrochemical devices having the same electrode surface area in a rectangular arrangement. The invention includes other illustrative embodiments (“Embodiments”) as follows. Embodiment 1: An electrochemical device, comprising: a rotating assembly, comprising: a membrane electrode assembly (MEA) having an anode, a cathode, and a membrane disposed between the anode and the cathode and separating the anode from the cathode, and an outer casing located around the MEA; and a shaft coupled to the rotating assembly and configured to rotate the rotating assembly via rotation of the shaft, wherein the shaft extends through the rotating assembly and includes a first port formed therethrough, wherein the first port is at least part of a flow path configured to introduce liquid into the rotating assembly. Embodiment 2: The electrochemical device of Embodiment 1, wherein the shaft further includes a second port formed therethrough, wherein the second port is at least part of a second flow path configured to retrieve a first gas product of an electrochemical reaction in the rotating assembly and transport the first gas product of the electrochemical reaction to a first outlet outside the rotating assembly. Embodiment 3: The electrochemical device of Embodiment 2, wherein the shaft further includes a third port formed therethrough, wherein the third port is at least part of a third flow path configured to retrieve a second gas product of the electrochemical reaction in the rotating ATTORNEY DOCKET 092119.0111 assembly and transport the second gas product of the electrochemical reaction to a second outlet outside the rotating assembly, the second outlet being separate from the first outlet. Embodiment 4: The electrochemical device of Embodiment 3, further comprising at least one pressure regulator coupled to the second port and / or the third port at a position downstream of the second port and / or the third port. Embodiment 5: The electrochemical device of Embodiment 1, further comprising a wire extending through a fourth port formed through the shaft, the wire being electrically coupled to the anode and / or the cathode of the MEA. Embodiment 6: The electrochemical device of Embodiment 5, further comprising: an electric power converter disposed in or along the shaft and / or the rotating assembly, the electric power converter being coupled to the wire and configured to output DC current to the wire or to receive DC current from the wire; and an inductive coil disposed in or along the shaft and coupled to the electric power converter, the inductive coil being configured to provide AC power to the electric power converter or to output AC power from the electrochemical device. Embodiment 7: The electrochemical device of Embodiment 1, further comprising at least one wired communication path extending through at least one port formed through the shaft. Embodiment 8: The electrochemical device of Embodiment 1, wherein: the anode comprises an inactive portion located thereon, the cathode comprises an inactive portion located thereon, the inactive portion of the anode is located at a same circumferential position and at a same radial position with respect to a rotational axis of the MEA as the inactive portion of the cathode, and an orifice is formed in the membrane at a location corresponding to the same circumferential position and the same radial position with respect to the rotational axis of the MEA as the inactive portions of the anode and the cathode. ATTORNEY DOCKET 092119.0111 Embodiment 9: The electrochemical device of Embodiment 1, wherein the rotating assembly further comprises a plurality of MEAs, each MEA including an anode, a cathode, and a membrane, interposed with a plurality of bipolar plates, wherein the plurality of MEAs and the plurality of bipolar plates are stacked with respect to each other to form a plurality of chambers within the rotating assembly, each chamber having an anode or a cathode therein. Embodiment 10: The electrochemical device of Embodiment 1, wherein the electrochemical device is an electrolyzer or a fuel cell. Embodiment 11: An electrochemical device, comprising: a rotating assembly, comprising: a membrane electrode assembly (MEA) having an anode, a cathode, and a membrane disposed between the anode and the cathode and separating the anode from the cathode, and an outer casing located around the MEA; a shaft coupled to the rotating assembly and configured to rotate the rotating assembly via rotation of the shaft; a wire extending at least partially through the shaft and coupled to the anode and / or the cathode; an electric power converter disposed in or along the shaft and / or the rotating assembly, the electric power converter being coupled to the wire and configured to output DC current to the wire or to receive DC current from the wire; and an inductive coil disposed in or along the shaft and coupled to the electric power converter, the inductive coil being configured to provide AC power to the electric power converter or to output AC power from the electrochemical device. Embodiment 12: The electrochemical device of Embodiment 11, wherein: the electric power converter is an AC / DC converter configured to output DC current to the wire for supplying power to the MEA, and the inductive coil is configured to provide AC current to the AC / DC converter. ATTORNEY DOCKET 092119.0111 Embodiment 13: The electrochemical device of Embodiment 12, wherein the inductive coil forms part of an induction motor configured to rotate the shaft, wherein a portion of the AC current in the inductive coil is output to the AC / DC converter and the rest of the AC current in the inductive coil is used to rotate the shaft. Embodiment 14: The electrochemical device of Embodiment 11, wherein: the electric power converter is a DC / AC converter configured to receive DC current from the wire, and the inductive coil is configured to output AC power from the electrochemical device. Embodiment 15: The electrochemical device of Embodiment 11, wherein the shaft extends through the rotating assembly and includes a first port formed therethrough, wherein the first port is at least part of a first flow path configured to introduce liquid into the rotating assembly. Embodiment 16: The electrochemical device of Embodiment 11, wherein the electrochemical device is an electrolyzer or a fuel cell. Embodiment 17: A method, comprising: rotating an electrochemical assembly via a shaft, the electrochemical assembly comprising at least one membrane electrode assembly (MEA) located therein, each MEA comprising a respective anode and cathode separated by a membrane, wherein the shaft extends through the electrochemical assembly; introducing liquid into the rotating assembly via one or more flowpaths formed through the shaft; performing an electrochemical reaction via the electrochemical assembly while rotating the at least one MEA; and outputting, from the electrochemical assembly, at least one product generated by the electrochemical reaction. Embodiment 18: The method of Embodiment 17, further comprising: outputting AC current from an inductive coil to an AC / DC converter, the inductive coil disposed in or along the ATTORNEY DOCKET 092119.0111 shaft and the AC / DC converter disposed in or along the shaft and / or the rotating assembly; outputting DC current from the AC / DC converter; and communicating the DC current to the anode and / or the cathode of the MEA via a wire extending at least partially through the shaft. Embodiment 19: The method of Embodiment 18, further comprising: rotating the shaft via an induction motor comprising the inductive coil; outputting a portion of the AC current in the inductive coil to the AC / DC converter; and using the rest of the AC current in the inductive coil to rotate the shaft. Embodiment 20: The method of Embodiment 17, further comprising: causing the liquid to move, via acceleration from the rotating assembly, to active areas along the anode and the cathode, the active areas each being between a first radial position at an outer rim of the rotating assembly and a second radial position located between the outer rim and a center of the rotating assembly; wherein the electrochemical reaction is performed in the active areas. Embodiment 21: The method of Embodiment 17, further comprising: balancing pressure between a first chamber having the anode on a first side of the membrane and a second chamber having the cathode on a second side of the membrane, via an orifice formed in the membrane, wherein the anode and the cathode each comprise an inactive portion located proximate the orifice in the membrane. Embodiment 22: An electrochemical device, comprising: a housing having a top surface and a bottom surface, the electrochemical device configured to be supported on the bottom surface of the housing; an anode disposed in the housing; a cathode disposed in the housing; a membrane disposed in the housing between the anode and the cathode, the membrane separating the anode and the cathode, wherein the electrochemical device is an electrolyzer or a fuel cell, and wherein the anode and the cathode each have a rectangular shape defined by upper and lower ATTORNEY DOCKET 092119.0111 edges and two side edges connecting the upper and lower edges, the upper edge being located proximate the top surface of the housing and the lower edge being located proximate the bottom surface of the housing, and the upper and lower edges having a greater length than the two side edges. Embodiment 23: The electrochemical device of Embodiment 22, wherein the upper and lower edges are oriented in a horizontal direction while the two side edges are oriented in a vertical direction when the electrochemical device is supported on the bottom surface of the housing. Embodiment 24: An electrochemical device, comprising: a housing having a top surface and a bottom surface, the electrochemical device configured to be supported on the bottom surface of the housing; an anode disposed in the housing; a cathode disposed in the housing; and a membrane disposed in the housing between the anode and the cathode, the membrane separating the anode and the cathode, wherein the electrochemical device is an electrolyzer or a fuel cell, and wherein the anode and the cathode each have a triangular shape defined by an upper edge and two side edges connected to opposite ends of the upper edge, the upper edge being located proximate the top surface of the housing. Embodiment 25: The electrochemical device of Embodiment 24, wherein the upper edge is oriented in a horizontal direction when the electrochemical device is supported on the bottom surface of the housing. Embodiment 26: An electrochemical device, comprising: a housing having a top surface and a bottom surface, the electrochemical device configured to be supported on the bottom surface of the housing; an anode disposed in the housing; a cathode disposed in the housing; and a membrane disposed in the housing between the anode and the cathode, the membrane ATTORNEY DOCKET 092119.0111 separating the anode and the cathode, wherein the electrochemical device is an electrolyzer or a fuel cell, wherein the anode and the cathode each have a non-rectangular shape, and wherein the non-rectangular shape of the anode and the cathode, when viewed in a direction perpendicular to the plane of the anode and / or cathode, has a centroid located closer to the top surface of the housing than to the bottom surface of the housing. Embodiments illustrated under any heading or in any portion of the disclosure may be combined with embodiments illustrated under the same or any other heading or other portion of the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context. For example, and without limitation, embodiments described in dependent claim format for a given embodiment (e.g., the given embodiment described in independent claim format) may be combined with other embodiments (described in independent or dependent claim format). Numerous modifications, alterations, and changes to the described embodiments are possible without departing from the scope of the present invention defined in the claims. It is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.

Claims

ATTORNEY DOCKET 092119.0111 CLAIMS What is claimed is:

1. An electrochemical device, comprising: a rotating assembly, comprising: a membrane electrode assembly (MEA) having an anode, a cathode, and a membrane disposed between the anode and the cathode and separating the anode from the cathode, and an outer casing located around the MEA; and a shaft coupled to the rotating assembly, wherein the shaft extends through the rotating assembly and includes a first port formed therethrough, wherein the first port is at least part of a flow path configured to introduce liquid into the rotating assembly.

2. The electrochemical device of claim 1, wherein the shaft further includes a second port formed therethrough, wherein the second port is at least part of a second flow path configured to retrieve a first gas product of an electrochemical reaction in the rotating assembly and transport the first gas product of the electrochemical reaction to a first outlet outside the rotating assembly.

3. The electrochemical device of claim 2, wherein the shaft further includes a third port formed therethrough, wherein the third port is at least part of a third flow path configured to retrieve a second gas product of the electrochemical reaction in the rotating assembly and transport the second gasATTORNEY DOCKET 092119.0111 product of the electrochemical reaction to a second outlet outside the rotating assembly, the second outlet being separate from the first outlet.

4. The electrochemical device of claim 3, further comprising at least one pressure regulator coupled to the second port and / or the third port at a position downstream of the second port and / or the third port.

5. The electrochemical device of claim 1, further comprising a wire extending through a fourth port formed through the shaft, the wire being electrically coupled to the anode and / or the cathode of the MEA.

6. The electrochemical device of claim 5, further comprising: an electric power converter disposed in or along the shaft and / or the rotating assembly, the electric power converter being coupled to the wire and configured to output DC current to the wire or to receive DC current from the wire; and an inductive coil disposed in or along the shaft and coupled to the electric power converter, the inductive coil being configured to provide AC power to the electric power converter or to output AC power from the electrochemical device.

7. The electrochemical device of claim 1, further comprising at least one wired communication path extending through at least one port formed through the shaft.ATTORNEY DOCKET 092119.0111 8. The electrochemical device of claim 1, wherein: the anode comprises an inactive portion located thereon, the cathode comprises an inactive portion located thereon, the inactive portion of the anode is located at a same circumferential position and at a same radial position with respect to a rotational axis of the MEA as the inactive portion of the cathode, and an orifice is formed in the membrane at a location corresponding to the same circumferential position and the same radial position with respect to the rotational axis of the MEA as the inactive portions of the anode and the cathode.

9. An electrochemical device, comprising: a rotating assembly, comprising: a membrane electrode assembly (MEA) having an anode, a cathode, and a membrane disposed between the anode and the cathode and separating the anode from the cathode, and an outer casing located around the MEA; a shaft coupled to the rotating assembly and configured to rotate the rotating assembly via rotation of the shaft; a wire extending at least partially through the shaft and coupled to the anode and / or the cathode; an electric power converter disposed in or along the shaft and / or the rotating assembly, the electric power converter being coupled to the wire and configured to output DC current to the wire or to receive DC current from the wire; andATTORNEY DOCKET 092119.0111 an inductive coil disposed in or along the shaft and coupled to the electric power converter, the inductive coil being configured to provide AC power to the electric power converter or to output AC power from the electrochemical device.

10. The electrochemical device of claim 9, wherein: the electric power converter is an AC / DC converter configured to output DC current to the wire for supplying power to the MEA, and the inductive coil is configured to provide AC current to the AC / DC converter.

11. The electrochemical device of claim 10, wherein the inductive coil forms part of an induction motor configured to rotate the shaft, wherein a portion of the AC current in the inductive coil is output to the AC / DC converter and the rest of the AC current in the inductive coil is used to rotate the shaft.

12. The electrochemical device of claim 9, wherein the shaft extends through the rotating assembly and includes a first port formed therethrough, wherein the first port is at least part of a first flow path configured to introduce liquid into the rotating assembly.

13. The electrochemical device of claim 1, wherein the shaft is configured to rotate the rotating assembly via rotation of the shaft.

14. A method, comprising:ATTORNEY DOCKET 092119.0111 rotating an electrochemical assembly via a shaft, the electrochemical assembly comprising at least one membrane electrode assembly (MEA) located therein, each MEA comprising a respective anode and cathode separated by a membrane, wherein the shaft extends through the electrochemical assembly; introducing liquid into the rotating assembly via one or more flowpaths formed through the shaft; performing an electrochemical reaction via the electrochemical assembly while rotating the at least one MEA; and outputting, from the electrochemical assembly, at least one product generated by the electrochemical reaction.

15. The method of claim 14, further comprising: outputting AC current from an inductive coil to an AC / DC converter, the inductive coil disposed in or along the shaft and the AC / DC converter disposed in or along the shaft and / or the electrochemical assembly; outputting DC current from the AC / DC converter; and communicating the DC current to the anode and / or the cathode of the MEA via a wire extending at least partially through the shaft.

16. The method of Embodiment 14, further comprising: causing the liquid to move, via acceleration from the rotating electrochemical assembly, to active areas along the anode and the cathode, the active areas each being between a first radialATTORNEY DOCKET 092119.0111 position at an outer rim of the rotating assembly and a second radial position located between the outer rim and a center of the electrochemical assembly; wherein the electrochemical reaction is performed in the active areas.

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