DE3503003A1 - Fuel cell for generating electrical energy in the form of direct current, alternating current or three-phase current - Google Patents

Abstract

A novel fuel cell and the associated technology are described. This cell permits the direct generation of direct current, alternating current or three-phase current via the combustion of conventional, gasifiable fuels. This is achieved by the irreversible oxidation processes taking place wholly or partly upstream of the catalyst electrodes, it being possible to expose these to a pulsating gas stream having an oxidant concentration which fluctuates in a contrary sense. Owing to reduced internal resistances, the cell is endowed with an improved efficiency and better power capacity. It is intended to be used both in large-scale industrial fields and for mobile applications.

Description

PATENT DESCRIPTION

Fuel cell for generating electrical energy in the form of Direct, alternating or three-phase current The invented fuel cell transforms gasoline Fuels through oxidation into electrical energy. The irreversible oxidation of the Fuel is wholly or partly in the heatable combustion chamber the catalyst electrodes instead. Depending on the structure of the energy system, equal, Alternating or three-phase current can be generated directly from the cell.

The fuel cells developed so far are direct current generators. Their other main disadvantages are the unfavorable power / mass ratio as well too low a current density on the catalyst surfaces. Besides these disadvantages lead also design difficulties lead to the ultimate breakthrough of the fuel cell for everyday technology has not yet taken place.

The invention is based on the following object: Construction of a easy to build fuel cell, which is technically more common even when used Fuels with high current densities on the catalyst surfaces and low weight in addition to direct current, especially alternating current or

Can generate three-phase current.

This object is achieved according to the invention in that a for electricity generation necessary partial pressure gradient of hot fuel gas between the anode and cathode compartments or oxidant is maintained between the cathode and anode compartment.

This is achieved when there is a combustion in the combustion chamber in front of the anode takes place with excess fuel gas, while in the combustion chamber in front of the cathode a Combustion is carried out with excess oxidant (see Fig. 1). With this burn is also the energy for heating at the same time and reforming generated. Achieved with pulsating gas flows with changing oxidant concentration there is an opposing, constantly changing change in the partial pressure in the electrode spaces. The pulsation frequency of the gas flow then corresponds exactly to the frequency of the generated one Alternating current and can be optimized for the power capacity of the cell (see Fig. 2). By combining several such cells with the correspondingly pulsating ones Three-phase current can be generated for gas flows. With this alternating current technology, the continuous transport of ions through the electrolyte from one electrode to the others no longer required. Hence, the electrolyte and the one lying on it Catalyst electrode in a very thin layer on any conductive metal be applied. This greatly reduces the internal resistance of the cell and their efficiency and power capacity are increased accordingly.

The advantages achieved with the invention are as follows: 1. The irreversible ones Oxidation processes for power generation as well as reforming and heating take place in one open, as small as possible combustion chamber in front of the corresponding electrode. this causes a simple design that is technically possible even for very high temperatures the fuel cell.

2. The fuel cell can directly handle the technically important or generate three-phase current.

3. With the alternating current technology mentioned, the two electrodes not be directly connected by the electrolyte because of the continuous ion transport is no longer required in the electrolyte between the electrodes. It is therefore possible to apply the electrolyte in a very thin layer on a metal surface. This greatly reduces the internal resistance of the cell and its efficiency increased accordingly.

4. Ultimately, all the improvements taken together make the opportunity for the construction of a relatively small fuel cell with high power density and good efficiency.

It can be used for mobile purposes as well as in large-scale systems can be used to generate electrical energy.

The following is an example of how the fuel cell works described: In order to keep a cell in readiness, the two rooms are with the electrodes are heated directly by burning gaseous fuel. Included the two burners are set so that total combustion takes place. The hydrogen partial pressure in both rooms is therefore the same.

This in turn causes the hydrogen ion concentration at both Electrodes in the electrolyte is the same. So there is equilibrium everywhere and no directional current flow develops across the electrodes.

If the cell is to provide power, the amount of gas for the anode compartment is regulated in such a way that the partial pressure of hydrogen increases with the same heating output. The increased partial pressure on the gas side of the anode causes the hydrogen ion concentration to rise on the electrolyte side of the anode.

The now resulting concentration gradient in the electrolyte is looking for itself to be balanced by diffusion and field forces.

This also leads to an increase in the concentration of the hydrogen ions at the cathode. There, however, the hydrogen partial pressure on the gas side is reduced by excess greatly reduced in oxidant, so that the hydrogen ions intensified over the metal catalyst under absorption of electrons enter the gas space as hydrogen. There is now the oxygen partial pressure is regulated so that the escaping hydrogen oxidizes immediately and is discharged. (The same process can occur under other conditions with the oxidant.) Are the anode and cathode conductive via a working resistor connected, the electron flow corresponds exactly to the ion flow in the electrolyte. He can only be maintained by the oxidation of the hydrogen in the cathode compartment will.

The increased hydrogen ion concentration limits the exposure to heavy loads at the anode, among other things, the current flow. To the power capacity of this cell Now to increase it significantly, the concentration polarity must be suppressed. This is done by setting the hydrogen partial pressure in the two electrode spaces on the gas side changes permanently, in opposite directions with one to be optimized for each cell type Frequency.

This constant change in partial pressure is caused by pulsating gas flows generated. When one electrode is in a hydrogen atmosphere, there is at the counter electrode there is an oxidizing atmosphere, and vice versa. In the same sense the direction of the current also changes continuously (see Fig. 2).

So you generate alternating current. By an arrangement of three and more Electrodes can also be generated three-phase current. Depending on the boundary conditions of the cell, now their power capacity multiplied with increasing pulsation frequency of the gas will.

It is also possible with the invention to generate alternating current, if the fuel cell has only one combustion chamber and catalyst electrode and the counter electrode connected by the electrolyte is made of any Conductor (see Fig. 3).

Claims (4)

Claims: 1. Fuel cell for generating electrical Energy from gasifiable fuels, characterized in that it is used to generate electricity necessary partial pressure gradient of fuel gas or oxidant between the anode and cathode compartments is maintained in that a continuous combustion in the anode compartment with excess fuel, while continuous combustion in the cathode compartment takes place with excess oxidant, at the same time the heat of combustion achieved in the electrode chambers for heating the electrodes and, if necessary, for Reforming the fuel gas is used. 2. Fuel cell according to claim 1, characterized in that the Catalyst electrodes in opposite directions from a pulsating gas flow with alternating Oxidant concentration are flowed around, so that the partial pressure gradient of the fuel gas constantly changes between the electrodes and alternating current or three-phase current is generated. 3. Fuel cell according to claim 2, characterized in that the pulsating gas flow only hits a catalyst electrode in one combustion chamber, while the counter electrode is unaffected by the gas flow and the combustion processes remain. 4. Fuel cell according to claim 1, 2 and 3, characterized in that that one switches several of the cells described in parallel or in series.