Varta Batterie Aktiengesellschaft

Hoechst Aktiengesellschaft

Varta Geratebatterie Gmbh

August Winsel

Thomas Czerny

Hans Von Dohren

Kurt Ziegler, Deceased

Lothar Losch

Hans Sauer

Konrad Holl

Dejan Ilic

Helmut Laig-Horstebrock

Rudolf Staab

Hans-Joachim Kohnke

Ernst Voss

Waldemar Borger

Eckart Buder

Margarete Jung

Joachim Helmke

Konstantin Ledjeff

Welf Dennstedt

Nikolaj Medic

Bernd-Udo Bopp

An electrochemical gas sensor has a first gas diffusion electrode for a first reaction gas, which is inactive with respect to a second reaction gas at least in a first potential window, and a second gas diffusion electrode for the second reaction gas, which is active with respect to the second reaction gas at least in a second potential window for measuring two different gases in gas mixtures in a casing. The two gas diffusion electrodes are electronically isolated from one another, but electrically connected electrolytically to a reversibly loadable electrode and have contacts for connecting external closing circuits for adjusting the cell currents. The gas mixture is fed to the gas diffusion electrodes in series or parallel. The casing containing the electrodes is, in particular, in the form of a button cell. The reversibly loadable electrode is a Cu/CuO, Zn/ZnO or hydrogen electrode. The gas diffusion electrodes have a porous structure based on carbon or have a porous silver structure.

Electrochemical gas sensor

A process which comprises thermally decomposing in an electrically heated vibrating helical conveyor, manganese carbonate (MnCO.sub.3 x H.sub.2 O) into a manganese oxide (predominantly of Mn.sub.2 O.sub.3 x Mn.sub.5 O.sub.8) catalyst at about 500.degree. C., and processing this catalyst into a highly active electrode paste by dry intensive mixing with a carbon-containing conductive material (carbon black, graphite or activated carbon) and PTFE as the binder. The resulting electrode paste can be rolled into a supporting net made from Ni or Ag. Also a two-step mixing process in which the catalyst powder is first premixed with small amounts of a conductive agent and a binder, compacted and granulated, and then combined with the larger residual amount of the intended amounts of conductive agent and binder in a second mixing step. The finished gas diffusion electrode has a biporous structure consisting of hydrophilic and hydrophobic pore canals, which is highly favorable for the transport processes and the electrochemical reaction. The electrode is useful in fuel cells, alkali chloride electrolyzers and air cells.

Plastic-bound gas diffusion electrode containing a manganese oxide

A process is described for electrolyzing aqueous alkali metal chloride solutions in a membrane cell which contains an anode chamber with the anode and a cathode chamber with the cathode, the two chambers being separated from one another by a cation exchanger membrane. The cathode is porous and foil-like. The cathode and cation exchanger membrane form the actual cathode chamber filled with catholyte and the cathode and cell wall form a gas space. Water is fed into the cathode chamber and alkali metal hydroxide solution is withdrawn from it, hydrogen is withdrawn from the cathode chamber and gas space, and aqueous alkali metal chloride solution is fed into the anode chamber and gaseous chlorine, together with depleted alkali metal chloride solution, is withdrawn from it. A direct voltage which is at least the same as the decomposition voltage is applied to the cathode and anode. A higher pressure is established in the cathode chamber than in the gas space.

Process for the electrolysis of alkali metal chloride solutions

In a galvanic primary element of the system Li/H.sub.2 O.sub.2, the aqueous cathode depolarizer H.sub.2 O.sub.2 is fixated as a polyurethane gel. It can thereby be controlled and caused to react with the anode metal in accordance with the current drain requirements. This is accomplished using a ram to press the gel toward a conductor which covers the lithium anode, which may take the form of a metal grid and/or a gas diffusion electrode. The oxygen which forms in the working layer through catalytic decomposition of hydrogen peroxide creates a gas bubble when the current is interrupted or the ram is stopped, thereby interrupting the further supply of hydrogen peroxide to the catalyst.

Lithium peroxide primary element

Galvanic high energy cells based on the aqueous system Li/H.sub.2 O.sub.2 are operated in conjunction with a fuel cell. The H.sub.2 /O.sub.2 gas mixture developed by the high energy cell is supplied first to the positive and then the negative electrode of the fuel cell. The required quantitative relationship of the two gases, corresponding to the stiochiometry of water, is provided either by adding O.sub.2 to the gas mixture, or by separating O.sub.2 by means of an O.sub.2 /O.sub.2 gas chain, operating as a cleaning cell.

Method and apparatus for operating aqueous galvanic high energy cells

A manufacturing process for nickel (II) hydroxide suitable as active positive electrode material in alkaline electrochemical cells transforms solid Ni(NO.sub.3).sub.2 directly into Ni(OH).sub.2 using sodium hydroxide and with the least possible homogeneous solute phase of Ni.sup.2+ ions. Ni(NO.sub.3).sub.2 is deposited on the lower end of a diagonally upward moving conveyor belt, to which concentrated NaOH is supplied from the opposite direction. The depressions in the conveyor belt, which prevent downward sliding of the reaction product, discharge at the upper end Ni(OH).sub.2, together with easily separable NaNO.sub.3. At the lower end, the used NaOH is discharged. It can be reconcentrated, after separation of entrained NaNO.sub.3, in a vacuum evaporator and reused. The intermediate products of the process are basic nickel nitrates, for example of the composition Ni(NO.sub.3).sub.2 .times.Ni(OH).sub.2 .times.6H.sub.2 O.

Manufacturing process for nickel (II) hydroxide

A recombination system for catalytic oxidation of hydrogen in storage battery gases includes a gas supply duct which makes it possible for the combustible gas flowing through it to aspirate from the ambient the necessary combustion air, following the principle of a Bunsen burner, and to entrain it to the recombination catalyst. In case of over-supply of gas, an acid separator positioned in the gas supply pipe counteracts the gas aspiration by means of its flow impedance and thereby makes the recombination system safe from overload. It can also be connected following a conventional recombiner, thereby increasing its effectiveness, by receiving the excess hydrogen from same and reacting it with the aid of the air aspiration.

Recombination system for storage batteries

A galvanic primary element of the system Li/H.sub.2 O.sub.2 comprises a gas diffusion electrode which separates the lithium electrode from the cathode space which is filled with aqueous H.sub.2 O.sub.2 solution. In the working layer which is flanked by capillary active cover layers of the gas diffusion electrode, automatically drawn-in H.sub.2 O.sub.2 is decomposed into H.sub.2 O.sub.2 and O.sub.2 catalytically until the gas pressure is in equilibrium with capillary forces and thereby interrupts the access of additional H.sub.2 O.sub.2 solution to the working layer. Short circuiting of the cell or connection of a load causes a reduction of the gas pressure due to electrochemical reaction of the O.sub.2 with the lithium so that fresh reactant solution can flow in. A reaction regime matching the current draw becomes possible because of the property of polyurethane to gel in aqueous H.sub.2 O.sub.2 by virtue of the fact that the H.sub.2 O.sub.2 is slowly pressed out of the gel as out of a sponge by means of a ram toward the gas diffusion electrode.

Galvanic primary element

A palladium-containing catalyst mat is made of a rolled PTFE-Kieselgur mixture which has been soaked with PdCl.sub.2 solution. It is made hydrophobic after soaking by treatment with a PTFE-Emulsion. Finally, it is subjected at about 430.degree. C. to a process which is similar to sintering and in which very finely divided Pd is produced through heat decomposition of the PdCl.sub.2. The catalyst mat is preferably combined with a carbon mat impregnated with CuO which, for example, may be a carbon felt which has been made denser through roller compression.

Hydrophobic catalyst for recombiners

Combined operation between a lithium high-energy cell of the Li/H.sub.2 O or Li/H.sub.2 O.sub.2 system, a fuel cell, and if appropriate a storage battery can be carried out with favorable energy balance by producing on the one hand so much CO.sub.2 using a methanol reformer in accordance with ##STR1## as is required for the combination of the LiOH created during the cell reaction in the Li cell into Li.sub.2 CO.sub.3 and, on the other hand, obtaining H.sub.2 which is supplied to the fuel cell together with O.sub.2 from an H.sub.2 O.sub.2 decomposer. The complete energy supply system contains a gas washer for the reaction of the CO.sub.2 with the LiOH and is also equipped with a set of reservoirs for the various reactants, for Li, for methanol, for H.sub.2 O.sub.2, for H.sub.2 O, for H.sub.2 and for O.sub.2. The current consumption of a motor used as load and the load equalization of the components among themselves is controlled by regulator devices.

Method and apparatus for electrochemical energy production

Bi-directional valve means are provided between the interior and the ambient, opening outward at a predetermined internal overpressure, and inward at a predetermined underpressure.

Storage battery with aqueous electrolyte and recombiner

Precipitation of metal salts from solution onto the electrode support structure takes place in several consecutive stages, with the precipitating solution caused to move countercurrent to the electrodes being impregnated.

Application of active mass to porous electrode support structures

The active mass is supported by an antimony free or antimony poor grid having embedded therein antimony-containing storage bodies from which the antimony is released in controlled manner during the life span of the electrode.

Positive electrode for storage battery

In a galvanic element which has a tendency to leak electrolyte at the lid seal, there is formed, on the metal enclosure portion which bears against the seal, a passive oxide surface layer which is not reducible at the negative electrode potential.

Galvanic element, particularly alkaline storage battery

Catalytic material in powder form flows downwardly along a vibratory spiral conveyor chute, while gas flows counter to the powder, preferably in excess. Mixing ramp arrangements may be provided in the chute.

Growing community of inventors

Kelkheim, Germany

August Winsel