S.c.p.s. Societe De Conseil Et De Prospective Scientifique, S.a.

Sorapec S.a.

Societe Anonyme Automobiles Citroen

Sorapec, Societe De Recherche Et D'applications Electrochimiques

S.c.p.s.

S.c.p.s. S.a.

S.c.p.s. Societe De Coneil Et De Prospective Scientifique S.a.

Sorapec Societe De Recherches Et D'applications Electrochimiques

Seregie

Bernard Bugnet

Denis Doniat

Robert Rouget

Guy Bronoel

Noelle Tassin

Thierry Potier

Max Costa

Augusto Porta

Fabrice Fourgeot

Jacques Doniat

Olivier Breting

Silver positive electrode for alkali secondary batteries having an enhanced cycling capability, and consequently a longer lifetime in cycling of the storage batteries incorporating it, by optimizing, in recharge mode, the conditions for electrochemically reducing the oxidized silver species. The silver electrode according to the invention is of the plasticized type, and a high-porosity collector, such as a woven fabric, a felt or a reticulated cellular metal foam, is used. The active compound introduced into the collector is prepared in paste form, in which the active material consists of metallic silver particles and/or silver monoxide particles, and may advantageously include a metal oxide acting as pore-forming and wetting agent for the electrode. Such an electrode is particularly intended for mounting in silver-zinc storage batteries operating in open mode or sealed mode.

Silver positive electrode for alkaline storage batteries

The invention concerns a device for catalytic recombination of gases for alkaline batteries with shortened zinc anode. The invention concerns a device for catalytic recombination of gases formed when charging a zinc anode alkaline battery, characterized in that it consists of a catalytic mass in contact with a crosslinked cellular metal foam serving as catalyst support and heat dissipating structure, said catalytic mass consisting of a mixture of carbon black including metal of platinum metals, and of a hydrophobic binder, the whole assembly being heat-treated to cause the hydrophobic binder of said catalytic mass to be sintered. Said device is advantageously connected to one of the terminals of the battery or to any other metal part constituting part of the cover of the battery case, so as to promote discharge of the calories produced. Such a device enables, in a long lasting manner during the charge-discharge cycles, limited internal pressure levels to be maintained, in particular in installations designed to operate without maintenance.

Device for catalytic recombination of gases for alkaline batteries with shortened zinc anode

The invention relates to an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator. Said additive contains conductive ceramic powder, preferably titanium nitride particles which is exposed to an oxidation pre-treatment prior to the incorporation thereof into the active mass of the anode. Said ceramic powder is used as electronic conduction in the anode active mass and as zincates retention which are produced by generator discharge. In order to use said retentive capacity, the powder is exposed to an oxidation pre-treatment, whereby making it possible to form the binding sites on the surface of ceramic grains. The inventive additive makes it possible, starting from the first cycles of the electrode formation, to form uniform zinc deposits, thereby increasing the service life for the cycling of the zinc anode.

Ceramic conductor pre-treated by oxidising for a zinc anode

The invention relates to secondary alkaline electrochemical generators with a zinc anode in an electrolyte, the active mass of said anode comprising at least one conductive ceramic. According to the invention, the electrolyte of the generator is made up of a highly-concentrated alkaline solution and/or the active mass of the zinc anode contains an additive comprising at least one alkaline titanate having general formula (MO)(Ti))xHO, wherein M denotes Li, Na, K, Rb or Cs, n being between 0.5 and 2, m being between 1 and 10 and x being between 0 and 10, or alkaline earth having general formula (MO)(TiO)xHO, wherein M denotes Mg, Ca, Sr or Ba, n being between 1 and 5, m being between 1 and 10 and x being between 0 and 10. The invention also relates to the zinc anode of the generators used in the invention and the production method thereof.

Alkaline secondary electrochemical generators with a zinc anode

A complex porous structure of a reticulated foam, felt or fabric types, wherein their metallisation over their entire developed surface, by electrolysis of lead or lead alloys, is made possible by a specific preliminary conductive activation treatment obtained by using two consecutive phases of coating the developed surface of the structures, comprising a first deposition of a conductive polymer, which provides the structures with the required conductivity, and a second thin deposition of conductive lacquer or varnish which ensures the surface protection of the conductive polymer against the deactivating effect of the conductive nature of the latter, due to the cathodic polarisation of the said structures in the electrolytic lead-coating bath.

Lead-coated complex porous structures and corresponding method of conductive activation

The invention concerns the treatment of porous structures such as cross-linked foams, woven or nonwoven, to make them electrically conductive by depositing polymers. The device enables, in a chemical reactor, to perform the activating treatment directly through non-reeled off blocks or rolls of porous structures, the treating fluids of the successive steps being made to circulate inside said blocks or rolls, via a perforated rotary mandrel whereon they are pressed. Said device enables to activate efficiently the structures, which may be metal-coated or not, and are particularly designed to be used as electrodes for liquid effluent electrolysis, of detectors and traps of organic or biological molecules, electrode supports for electrochemical generators, catalyst supports, filtering media, acoustic insulants, electromagnetic, nuclear and antistatic protection structures, heat exchangers and the like.

Device for activating conductivity in porous structures

The invention concerns the manufacture of complex metallic or metallized porous structures, wherein the electroplating metal over the entire developed surface is preceded by a specific pre-metallization of the basic structure. The pre-metallization is obtained by depositing a conductive polymer, which is deposited on the entire developed surface of the structure by the steps of an oxidizing pre-treatment of the structure, depositing in the liquid phase, a monomer having a polymerized form that is electrically conductive, and polymerizing by oxidation-doping of the monomer. The structures according to the invention are particularly intended for use as electrodes for the electrolysis of liquid effluents, as electrode supports for electrochemical generators, as catalyst supports, filtration media, phonic insulation, electromagnetic and nuclear protection structures, or for other applications.

Porous structures having a pre-metallization conductive polymer coating and method of manufacture

Secondary electrochemical generators of the zinc-electrode alkaline type whose anode has a great capacity for cycling. The electrochemical generators according to the invention comprise zinc anodes made in such a manner as to increase within the active material the number of sites for formation of zinc during recharging, by a better draining of the electrical charges, obtained by using a dispersed secondary collector in the form of a conductive powder in the active mass, to which may advantageously be associated a principal support-collector of the high porous three-dimensional structured type having a high developed surface. These generators thus have zinc electrodes of improve cyclability, the number of charges and discharges that the electrode can perform under different regimes being increased.

Secondary electrochemical generators of the zinc-anode alkaline type

The invention concerns complex porous structures varying in thickness and the method used for making them electrically conductive by conductive polymer deposit. The conductive activation is obtained by depositing a conductive polymer, set on the whole developed surface of the structure through its entire thickness, by pre-treatment steps for oxidizing the structure, depositing a monomer, polymerizing oxidaton-doping of the monomer. The structures are of the type crosslinked foam, felt or woven fabric and are mass-treated by flowing treatment solutions within blocks, still unwound rolls. Said structures, which can be metal-coated or not, are particularly designed to be used as electrodes for the electrolysis of effluent liquids, detecting and trapping organic or biological molecules, supporting electrodes for electrochemical generators, catalyst supports, filtering media, sound insulating materials, electromagnetic, nuclear, antistatic protecting structures, heat exchangers and others.

Method for conductive activation of thick complex porous structures

The invention relates to metallic products and a process for producing these which allows, despite the complexity of their structure, for them to be produced in refractory alloys based on chromium. The chromium is deposited by electrolysis, this being carried out by means of a bath with high throwing power. The formation of the alloy with layers of other metallic constituents is obtained by thermal diffusion. The provision of aluminum is controlled in the form of particles by immersing, by spraying or &ldquo;painting.&rdquo; The structures according to the invention are particularly intended to be used as catalyst supports or filtering agents.

High porosity three-dimensional structures in chromium based alloys

Bipolar electrode is provided with a conductive support/separator perforated on a part which is free from active material with at least one opening which communicates by a gaseous environment in a battery between elements assembled in series. The opening prevents the passage of electrolyte from one conductive support/separator to another, and may include an advantageously hydrophobic material, which also contains an opening therethrough, and is arranged on at least one side of the opening. The bipolar electrodes are particularly applicable to sealed batteries.

Bipolar electrode for batteries

The cadmium negative electrode has a structure serving as a collector and made of nickel foam. The sponge is filled with a mixture cons mainly of cadmium oxide and contains nickel sulphate hexahydrate in the proportion of 1.8 to 2.7% by weight of the total mixture, expressed in the form of nickel.

Method of making cadmium electrodes for alkaline batteries

A plasticized cadmium oxide electrode for an electrochemical generator and more specifically for a storage battery is formed by pasting a reticulated open-porosity matrix, a plasticizing agent being associated with cadmium oxide in the paste employed. This electrode has high capacity and offers outstanding stability during cycling.

Cadmium oxide electrode with binding agent

The cadmium negative electrode has a structure serving as a collector and made of nickel foam. The sponge is filled with a mixture consisting mainly of cadmium oxide and contains nickel sulphate in the proportion of 1.8 to 2.7% by weight of the total mixture, expressed in the form of nickel.

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Le Plessis Trevise, France

Bernard Bugnet