De Nora S.p.a.

De Nora Permelec Ltd

Claudio Mantegazza

Giuseppe Faita

Emilio Zioni

Massimo Brambilla

The invention describes a method for applying an electrocatalytic or a protective coating to a metal substrate or repairing a damaged area of the same, consisting in a thermal treatment of a precursor of said catalytic coating by means of a hot air jet from a blower. The temperature of the substrate is locally controlled by means of surface temperature sensors or by an infrared measuring system. The metal substrate may be an exhausted electrode structure, in which case the reactivation is easily carried out at the plant site without any need of sending the structure to the producer. The method of the invention is particularly useful for reactivating anodes for oxygen evolution as it permits to avoid the risky procedure of detaching the anode from the current conductor.

Method for applying a coating to a metal substrate or repairing a coating applied to the same

Method for applying a coating to a flange of an electrochemical cell or repairing a coating applied to the same

The invention concerns membrane electrolyzers suitable for processes such as water or hydrogen halides electrolysis, as well as electrochemical generators fed with gases containing hydrogen and oxygen for direct conversion into electric energy. These apparatuses generally consist of a filter-press assembly of conductive bipolar plates (2), electrodes (4), sealing gaskets (5) membranes (6) and internal longitudinal ducts for feeding the reactants and withdrawing the products and residual reactants. The invention is directed to the method for repairing said electrolyzers or generators when an elementary cell is malfunctioning. This method comprises making at least two perforations in the peripheral area of the bipolar plates (2) and/or gaskets (5) of the malfunctioning cell to reach distribution channels (9, 11) which connect the compartments containing the electrodes (4) with said longitudinal ducts. A sealing means (agent) is then injected through the perforations (12) in order to form suitable occlusions (14, 15) in the distributions channels (9, 11) and in the perforations (12) respectively. To facilitate the perforation procedure, the bipolar plate (2) and/or the gaskets (5) may be provided with blind aid-holes in the peripheral area. Upon sealing the distribution channels (9, 11) and the perforations (12), the bipolar plates (2) delimiting the malfunctioning cell are externally short-circuited and the electrolyzer or generator is ready for operation.

Method for excluding a malfunctioning elementary cell in a membrane

A membrane electrochemical cell, in particular a fuel cell, of an improved type comprising a multiplicity of cell elements, each element made up of bipolar plates, current collectors, electrodes and membranes, wherein the function of electric current transmission through the cell elements, the release of heat towards the outside environment, the distribution of electric current to the electrodes and membranes, the removal of heat from the electrodes and membranes and the distribution of the reactants and products are performed by distinct components, in particular bipolar plates for the first two and porous electroconductive collectors for the others. The bipolar plates may have flat surfaces without grooves and are preferably manufactured with aluminum, titanium or alloys thereof, through cheap mass productions techniques; the bipolar plates are used together with collectors provided with deformability, residual resiliency and high porosity. Said collectors advantageously act also as distributors of the gaseous reactants and of the products.

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Saronno, Italy

Claudio Mantegazza