The present invention provides a decentralized and compact energy production system utilising ammonia for storage-of electric power and ammonia or H.sub.2 for production of electric power and heat suitable for use by a single household or in a small commercial building.

Described herein are systems and methods of hydrogen generation and electrolyte regeneration as independent operations in separate redox flow cells. The operations can be decoupled by using an energy-bearing redox pair that electrochemically bears energy facilitating flexible, efficient hydrogen generation. In one example, the hydrogen generation redox flow cell can include a liquid, energy-bearing electrolyte solution in which at least one species of an energy-bearing redox pair is dissolved, to decouple the hydrogen evolution reaction from the reaction at the opposite electrode (e.g., the oxygen evolution reaction of conventional direct water electrolysis). Each species of the energy-bearing redox pair is associated with a standard electrode potential within the water electrolysis window.

Described herein are systems and methods of storing and delivering electrical using hydrogen at low-cost and for long-durations. The systems and methods use energy-bearing redox pairs that electrochemically bear energy through decoupled hydrogen and oxygen consumption and/or evolution reactions, which are typically associated with fuel cells. Each species of the energy-bearing redox pair is associated with a standard electrode potential within a water electrolysis voltage window for the electrolyte solution. Electrical energy delivery, hydrogen generation, electrolyte regeneration, or combinations thereof can be performed by logically or physically separated unit operations in a continuous manner, batch manner, or semi-batch manner facilitated by the energy-bearing redox pair.

Provided is a rechargeable electrochemical cell system for generating electrical current using a fuel and an oxidant. The system includes a plurality of electrochemical cells. A controller is configured to apply an electrical current between charging electrode(s) and a fuel electrode with the charging electrode(s) functioning as an anode and the fuel electrode functioning as a cathode, such that reducible metal fuel ions in the ionically conductive medium are reduced and electrodeposited as metal fuel in oxidizable form on the fuel electrode. The controller may selectively apply current to a charging electrode and third electrode between fuel electrodes of separate cells to increase uniformity of the metal fuel being electrodeposited on the fuel electrode. The controller controls a number of switches to apply current to the electrodes and select different modes for the system. Also provided are methods for charging and discharging an electrochemical cell system, and selecting different modes.

An innovative device that integrates, internally to one individual electrochemical cell, the functions of an electrolyzer, a hydrogen accumulator, and a fuel cell. The device can be recharged both electrically, by connecting it to a usual battery charger, and by way of a direct injection of gaseous hydrogen. The present device is very compact and features a reduced weight, consequently it can be advantageously used both to supply power to small-size portable electronic devices and to supply power to motors of electric vehicles.

Disclosed are fuel cell stack break-in procedures, conditioning systems for performing break-in procedures, and motor vehicles with a fuel cell stack conditioned in accordance with disclosed break-in procedures. A break-in method is disclosed for conditioning a membrane assembly of a fuel cell stack. The method includes transmitting humidified hydrogen to the anode of the membrane assembly, and transmitting deionized water to the cathode of the membrane assembly. An electric current and voltage cycle are applied across the fuel cell stack while the fuel cell stack is operated in a hydrogen pumping mode until the fuel cell stack is determined to operate at a predetermined threshold for a fuel cell stack voltage output capability. During hydrogen pumping, the membrane assembly oxidizes the humidified hydrogen, transports protons from the anode to the cathode across the proton conducting membrane, and regenerates the protons in the cathode through a hydrogen evolution reaction.

Fuel cell arrangement having an improved efficiency. The arrangement comprises one or more fuel cell units 110 and a methanation unit 200 and a control unit 300. The fuel cell unit comprises a water inlet 111, a hydrogen outlet 112 and an oxygen outlet 113. The methanation unit comprises a catalyst 222, a hydrogen inlet 213, a carbon oxide inlet 214 having a first controllable valve 215 and a methane outlet 216, wherein the hydrogen outlet of the first fuel cell unit is coupled to the hydrogen inlet of the methanation unit, and the methanation unit is adapted to convert hydrogen and carbon oxide into methane, wherein the control unit is adapted to control the first controllable valve so as to obtain an optimum converting process to convert hydrogen and carbon oxide into methane.

A process control system includes a storage chamber, a fuel cell in fluid communication with the storage chamber via a feed line, a suction dampening drum in fluid communication with the fuel cell via a product line, a compressor in fluid communication with the suction dampening drum and the storage chamber, a recycle line disposed between the feed line and the product line, and a pressure controller disposed in the recycle line. When the fuel cell is in an electrolysis mode, the pressure controller may be operated to maintain a minimum pressure level inside the drum.

An electrochemical apparatus includes a catholyte, an anolyte, and a separator disposed between the catholyte and the anolyte. The catholyte includes metal salt dissolved in water, thereby providing at least one metal ion. The anolyte includes a polysulfide solution. The separator is permeable to the at least one metal ion. During a charging process of the electrochemical apparatus, oxygen is generated in the catholyte, the polysulfide in the polysulfide solution undergoes a reduction reaction in the anolyte, and the at least one metal ion moves from the catholyte to the anolyte. During a discharging process of the apparatus, the oxygen is consumed in the catholyte, the polysulfide oxidizes in the anolyte, and the at least one metal ion moves from the anolyte to the catholyte.

A control system for operating a modular arrangement of electrolysis cells under variable input voltage conditions, such as those from renewable energy sources, to optimize operation by reducing under and over potential of cells. Energy supply and electrolyte flow to cells or groups of cells is interrupted or resumed in response to available electrical potential and the optimal electrical potential required by active cells.