Abstract: The present invention relates to a membrane electrochemical generator (100) characterized by improved electrical insulation and reduced volume. The membrane electrochemical generator (100) is fed with gaseous reactants and comprises a multiplicity of reaction cells (101) assembled in a filter-press configuration. Each of said reaction cells (101) is delimited by a pair of bipolar sheets (102), formed by a metallic central body (110) integrated in a frame (111) made of polymeric material. The polymeric material may be of the thermoplastic or thermosetting type and the frame (111) is laid on the metallic central body (110) by molding.

Abstract: An electrical generation system, a membrane fuel cell system, suitable for being employed in mobile application, for instance in vehicular applications as a direct electric current generation system comprising at least one polymer membrane fuel cell stack with means for adjusting the temperature of the cells comprising circulating a coolant inside the cells at constant flow-rate, the water and the thermal management of the system being regulated by acting only on the flow-rate of the air feed and on the cell inlet temperature of the coolant.

Abstract: The present invention relates to a membrane electrochemical generator (100) characterised by improved electrical insulation and reduced volume. The membrane electrochemical generator (100) is fed with gaseous reactants and comprises a multiplicity of reaction cells (101) assembled in a filter-press configuration. Each of said reaction cells (101) is delimited by a pair of bipolar sheets (102), formed by a metallic central body (110) integrated in a frame (111) made of polymeric material. The polymeric material may be of the thermoplastic or thermosetting type and the frame (111) is laid on the metallic central body (110) by moulding.

Abstract: The invention describes a bipolar unit consisting of a pair of metal plates at least one of which is corrugated, fixed by continuous and hydraulically impervious connections, and provided on the external surfaces thereof with porous electric current collectors also suitable for the distribution of the gaseous reactants. The collector facing the plate corrugations is interpenetrated therein, thereby achieving a continuous contact. Two bipolar units of the invention and one interposed MEA element are assembled to form an elementary fuel cell with an improved electric current distribution. Furthermore the channels formed between the mutually contacting surfaces of the plate pair by the corrugations of at least one of the plates of each bipolar unit, are crossed by a coolant allowing to optimally adjust the cell operative temperature.

Abstract: A bipolar unit comprising a pair of metal plates, at least one of which is corrugated, fixed by continuous and hydraulically impervious connections, and provided on the external surfaces thereof with porous electric current collectors suitable for the distribution of the gaseous reactants, the collector facing the plate corrugations is interpenetrated therein, thereby achieving a continuous contact and two bipolar units of the invention and one interposed MEA element being assembled to form an elementary fuel cell with an improved electric current distribution and the channels formed between the mutually contacting surfaces of the plate pair by the corrugations of at least one of the plates of each bipolar unit, are crossed by a coolant allowing to optimally adjust the cell operative temperature.

Abstract: A unit consisting of a fuel cell, provided with a first ion-exchange membrane, and an electrolysis cell, equipped with a second ion-exchange membrane, capable of operating as an electrochemical hydrogen pump in which the electrolysis cell sucks in the discharge gas of the fuel cell anodic compartment which contains hydrogen as the main component, ionizes the hydrogen on a suitable anodic catalyst, sends the so formed protons across the second ion-exchange membrane to a suitable cathodic catalyst where the protons are reconverted to hydrogen which is mixed to the fuel cell hydrogen feed.

Abstract: It is described a bipolar separator for polymer membrane fuel cell stacks, delimited by two sheets provided with fluid passage holes connected by means of a corrugated element and comprising a passage section for a thermostatting liquid, which allows to achieve the withdrawal of heat from the adjacent cells and the humidification and distribution of gases with a single integrated piece, simplifying the assembly and the hydraulic sealing of the stack.

Abstract: The present invention relates to a membrane electrochemical generator (200) formed by a multiplicity of reaction cells (201) mutually connected in electrical series and assembled according to a bipolar configuration. In accordance with the present invention, the thermal management of the membrane electrochemical generator (200) and the hydration of the membrane (204) are ensured by the injection of a cooling fluid, preferably liquid water, in the gaseous reactant feed. Such an injection takes place through a multiplicity of calibrated fluid injection holes (230) obtained in conductive bipolar plates (203) delimiting the reaction files (201). The cooling fluid can be preheated by passing through a collector/distributor structure (206) located in an additional cell (202).

Abstract: A membrane electrochemical generator comprises a multiplicity of reaction cells (101) mutually connected in series and assembled according to a filter-press type configuration. Each reaction cell is delimited by a pair of conductive bipolar plates (103), which comprises a multiplicity of first calibrated holes (113a) for the passage of the gaseous reactants and a multiplicity of second calibrated holes (113b) for the discharge of the reaction products and of the optional residual reactants. The cooling cells (102) comprises a rigid peripheral portion (102a), whereupon a gasket (117) is laid, defining and sealing on each face of such peripheral portion a zone of collection of the gaseous reactants (118a) and a zone of collection of the reaction products and of the residual reactants (118b). In a filter-press configuration, these two zones are respectively overlaid to the first calibrated holes to reach the active area of the reaction cells (101).

Abstract: A membrane fuel cell stack comprising metal current-collecting plates of high electrical conductivity made of aluminum or copper, having a reduced planform with respect to the one of the elementary cells, the galvanic-type corrosion phenomena affecting the current-collecting plates of the prior art and the consequent metal ion release in the circulating water are overcome.

Abstract: An electrochemical generator consisting of an alternation of membrane fuel cells and cooling cells with internal circulation of liquid water is described. The fuel cells are fed in at least one of the two compartments, anodic or cathodic, with dry gas, which is humidified through the passage of water coming from the adjacent cooling cell through a metal porous separating wall. The permeated liquid water contributes to the withdrawal of the heat of reaction by evaporating at least in part inside the fuel cells.

Abstract: The method for reusing current collectors/distributors is employed in an electrochemical generator (1, 20) comprising a multiplicity of elementary cells (2, 21) assembled in a filter-press configuration and comprising an array of conductive sheets (3) and of current collectors/distributors (7, 22). The method of the invention provides dissembling the electrochemical generator (1) once the presence of a damaged elementary cell (2, 21) is detected. Subsequently, the method of the invention provides repairing/replacing the damaged cell for later reassembling the electrochemical generator (1, 20) reusing the original current collectors/distributors (7, 22). to achieve this, while reassembling the electrochemical generator (1, 20), a mechanical means for adapting (8, 12, 13, 14, 15) is inserted between each conducting sheet (3) and the respective current collector/distributor (7, 21).

Abstract: The invention describes a method and the relevant devices for permitting an operation stable with time of a stack of membrane fuel cells fed with air and a gas containing hydrogen and at least 100 ppm of carbon monoxide, characterised in that it provides for an oxidising condition at the anodes of said cells in a self-adjusting continuous way or sequentially discontinuous way. Different embodiments of the invention are illustrated wherein the oxidising condition is obtained by adding to the gas containing hydrogen and carbon monoxide, oxygen produced in an electrolysis cell integrated to the fuel cell stack, or by flowing air through porous areas obtained in the bipolar plates or by resorting to high gas diffusion rate membranes, wherein the air flow rate is regulated in both cases by adjusting the pressure differential existing between air and the gas containing hydrogen and carbon monoxide.

Abstract: The invention is relative to a membrane-electrode assembly for fuel cells, comprising a state of the art ion-exchange polymeric membrane and state of the art gas diffusion electrodes, whose electrochemical properties are modified through the addition of a hydrophilic component localized in correspondence to one or both the electrodic interfaces and/or one or both the external surfaces of the membrane. The modified membrane-electrode assembly is characterized by high protonic conductivity and high efficiency even in the presence of small quantities of carbon monoxide, or of other contaminants contained in the fuel, even at temperatures as low as 100° C., being also suitable for medium temperature (100–160° C.) operation at relative humidity level lower than saturation.

Abstract: An improved design of gas fed polymeric membrane fuel cell stack is herein described. The stack is provided with a humidifying device which takes advantage of the atomization of a water stream over a high specific surface metallic material, and with a cooling circuit withdrawing the heat generated therein by thermal exchange on a peripheral region, external to the single cell active area. The device is particularly suited for high temperature and high current density operation.

Abstract: The invention relates to a stack of polymeric membrane fuel cells, wherein the removal of the heat generated by the production of electric energy and the humidification of the ion exchange membranes used as electrolytes are obtained by the direct injection of a water flow coming from a single hydraulic circuit. The stack thus produced is more compact, less expensive and easier to operate.

Abstract: A humidification device for polymeric membrane fuel cell stacks fed with gaseous reactants is disclosed. The gases supplied to the stack are previously fed in admixture with a stream of liquid water to a chamber filled with a reticulated material, whose highly subdivided geometry provides an extended exchange surface favouring the saturation of gas. The device is more efficient and compact than those known in the art.

Abstract: The invention describes a method for the direct connection of fuel cells to electrolyzers of electrochemical plants producing hydrogen as a by-product. The by-product hydrogen is fed to the fuel cells and the electric energy thereby produced is transferred to the electrolyzers, with the consequent saving of the overall energy consumption. The direct coupling avoids the need for DC/AC converters or voltage adjusters and may be effected either in series or in parallel. In the latter case the fuel cell are assembled in modules, the number and voltage of which is regulated by means of interrupters activated by a computerised control and supervision system. As an alternative, the voltage of the modules may be varied by varying the pressure of the air fed to the fuel cells.