Varta Batterie Aktiengesellschaft

Vb Autobatterie Gmbh

Volkswagen Ag

Helmut Laig-Horstebrock

Eberhard Meissner

August Winsel

Karsten Michels

Uwe Dierker

Winfried Krey

Gerhard Schneider

Dieter Ubermeier

A method for predicting the loading capability of an accumulator by measuring the current I, voltage U and temperature T of the accumulator, and comparing the measured values with the corresponding values of the response of an equivalent circuit diagram of the accumulator, the parameters of the components of the equivalent circuit diagram and the state variables are varied so that a match with the measured values is obtain. The loading capability is deduced from the matched parameters and state variables determined in this way. The equivalent circuit diagram has the form -Uo-R-C- and the input voltage U' of the equivalent circuit diagram is a voltage that is corrected with respect to the measured battery voltage U, the correction function containing as variables only the current I, the voltage U and the temperature T and as a nonlinear term a logarithmic dependency on I. By using the equivalent circuit diagram, the instantaneous loading capability, i.e., the response of the battery under a hypothetical load with an assumed current value I, is predicted by imposing this current value I on the equivalent circuit diagram with the found parameters and evaluating the voltage response calculated.

Method for predicting the loading capability of an electrochemical element

In a method for predicting the equilibrated open-circuit voltage of an electrochemical energy store by measuring the voltage settling response Uo(t) in a load-free period, a formulaic relationship between the equilibrated open-circuit voltage Uoo and the decaying voltage Uo(t) of the form Uoo&equals;Uo(t)&minus;w*ln(t)&minus;w*F(T) is used, the prefactor w being the experimentally determined slope of the dependency of Uo on ln(t) at the time t, w&equals;&minus;(uo(t )&minus;Uo(t ))/ln(t /t ), and Uo(t ) being the unloaded voltage Uo at the time t and Uo(t ) being the unloaded voltage Uo at the later time t >t , and F(T) being a function which depends only on the absolute temperature T of the energy store. The function F(T) has the general form F(T)&equals;(K&verbar;E/T)/(1&plus;q*w)/f(T), K, E and q being experimentally determined constants, T being the absolute temperature in kelvin, and f(T) being a function which contains only the absolute temperature T as a free parameter.

Method for predicting the equilibrated open-circuit voltage of an electrochemical energy store

In a process for determining the state of charge and the peak current loadability of batteries in the currentless pauses before and after a loading phase the no-load voltages U.sub.01 and U.sub.02 are measured. From them, with allowance for battery-specific parameters, especially the time curve of the no-load voltage, the true battery rest voltages U.sub.001 and U.sub.002 are computed. During the loading phase the converted current quantity q is measured and from the relationship U.sub.002 -U.sub.001 =C.sub.1 .multidot.q/Q.sub.0 the acid capacity Q.sub.0 of the battery is found. The relative state of charge SOC.sub.1 is determined from a curve of the rest voltage U.sub.00 linearized by the formula SOC.sub.1 =U.sub.002 /C.sub.1 -C.sub.2 as a function of the state of charge of the battery from which the absolute state of charge is calculated as SOC.sub.1 .multidot.Q.sub.0. From the internal resistance R.sub.1, a preassigned temperature and the last determined state of charge, a rest voltage is predicted for a later time from which, with the current necessary for starting the engine known, a pronouncement can be derived concerning the starting capacity of the battery.

Process for determining the state of charge and the peak current

Alkaline MnO.sub.2 /Zn cells having nickel-plated steel cups as the cathode collector show deterioration of their discharge characteristics after high-temperature storage, which can be prevented by an additive in the cathode paste which forms a strong complex with nickel. Nickel oxide layers of high ohmic resistance, which are the cause of the contact resistance between the cathode and the nickel coating of the steel cup, are accordingly dissolved or transformed. Imidazole, 2-picolinic acid, dimenthylglyoxime, 4,5-dihydroxbenzene-1,3-disulfonic acid and 1,10-phenanthroline are particularly effective additives for compounding into the cathode. Preferred amounts are between 0.001 wt. % and 1 wt. %.

Electrochemical cell

In connection with a metal oxide electrode in an alkaline electrolyte system, especially for a brownstone electrode, the presence of cobalt as a thin film or as an alloying consitituent at the surface of the positive current drain wire, which is preferably a nickel-plated steel cup or a deep-drawing steel plate, leads to a reduction of the contact resistance between the current drain wire and the MnO.sub.2. To apply the cobalt, the current drain wire is preferably polarized in an aqueous CoSO.sub.4 solution. The cobalt film, which is formed in a thickness of less than 1 micron (depending on the Co ion concentration and the selected current conditions), imparts resistance properties to the transition between the MnO.sub.2 and the nickel-plated current drain wire even after prolonged storage, which can otherwise only be achieved with gold-plated current drain wires.

Current conductor for a metal oxide electrode in an alkaline electrolyte

A gas venting plug which separates entrained moisture has a gas escape nozzle and cooperating impingement plate, and a return duct for the separated liquid. The nozzle opening and return ducting are so dimensioned that the hydrostatic pressure in the return ducting is higher than the liquid capillary pressure in the nozzle.

Gas venting battery plug

Separate cooling systems are provided for the heat of recombination and for the heat of condensation, respectively, of a hydrogen recombination reactor, such as used for lead storage batteries.

Growing community of inventors

Frankfurt-am-Main, Germany

Helmut Laig-Horstebrock