Electrochemical cell

The invention relates to a elektrochemische cell, in particular as a component of an accumulator consisting of a vessel with a built-Plattensatz with at least one plate as a negative electrode and a separator disposed between the plates, in which the electrolyte schwefelsaure is festgelegt.

Such electrochemical cells are known in the art. When plates are thereby Gitterplatten from rationalizing Bleilegierungen used, in which the active material is eingestrichen. In tubular plates bulk carrier consists of several mutually parallel tubular insulators, in which the material is packed.

To fix the electrolyte in lead-acid batteries, two systems currently used. Firstly, given that the determination of the dilute sulfuric acid by a highly porous microfiber fleece, the other by a gelled silica.

Both systems have their advantages and disadvantages. So occurs during Zyklisierens (successive discharge and charge) in with Glasvlies separated stationary cells a Säureschichtung to that through Lageänderungen the cells to resolve is, however, little by loading or unloading methods. This is especially true for high-standing cells.

When sulfuric acid determination by gel observed Although no acid stratification, but the Entladespannungsverlauf in the high-current discharge is much worse than in the AGM batteries.

Also with respect to the oxygen cycle, there is a difference between the two systems of the electrolyte down. While in Vliesfestlegung after a few discharges at ordinary Ladeschlußströmen than 90% recombination rate achieved, must be in the gel festgelegten electrolyte first cracks by water disposal herausbilden so that the while charging the positive electrode resulting oxygen on his way to the metallic lead of the negative electrode, see can. The formation of these cracks is done randomly. Their number, width and length can not control defined.

Thus, it may in the application, especially in uninterruptible power supply systems, in which the storage current is kept very small, take up to two years or more to achieve a recombination rate with the desired high efficiency.

A further considerable difference lies in the manufacturing process. Fleece-separated cells can be prepared with slightly modified, used in the accumulators industrial manufacturing equipment and form both tank and block box. With gel fixed cells are separated using a commercial separator and can then be formed in the block box method. Thereafter advantageously the electrolyte is tipped out, and the gel is filled. Blockkastenformationen in gelling electrolytes are possible, but require a lot of effort to Gasblasen at the end of the formation not in the gel include. Batteries whose electrolyte is set with gel, are more expensive because of the complex filling and the sharp fall in prices on the konkurierenden microfiber nonwovens manufacture. The filling gel is also so expensive, the thinner the electrodes and thus the smaller the to be filled free spaces between separator and electrode.

both systems also differ with respect to the thermal runaway. Because of the coarser pore system of the glass fiber nonwoven and the missing separator between the electrodes of different polarity, the oxygen can relatively freely move from its place of origin to be consumed negative electrodes. This allows the reaction so strong swaying in that the electrolyte to boil begins, evaporated, the Zellgefäß deformed and in the worst case an explosion occurs. In gel-filled cells must of oxygen through the small pore size of the gel system to diffuse a very lengthy process, or through the cracks to the negative Verzehrelektrode reach. Both processes have a limiting effect and thereby delay the thermal runaway. So he sets a much later and not as severe.

Another feature, in which the two electrolyte determination types are different, is the replenishment of decomposed or vaporized electrolyte water. Even at the cost of acid stratification can yet be replenished if an excessive water loss in water nonwoven separated cells. A shrunken by excessive water loss gel swells back by adding water is no longer in its original state.

Slight increase in capacity of reducing capacity can be achieved, however.

Vessels for batteries or cells are often due to the Ausbauchungen in operation, especially when charging, with Stabilisierungsrippen provided. The dimensions, the number and shape of these stabilizing ribs depend mainly on the operating conditions, the vessel material, the vessel dimensions and the inner disk set structure from. Usually, one calculates such stiffeners with finite element programs that can be more or less complex and expensive, depending on the requirements and desired accuracy.

To those bulges on the broad sides of the plate package adverse impact in terms of capacity waste can have because of the required optimum pressure of the disk set, can not be dispensed with ribbing.

Another point, which in the design of the ribs little attention is, is the incidence of vascular walls in Unterdruck in the valved cells. Vacuum occurs whenever the cell is well charged or longer time were to trickle charge, have a good gas consumption and after a long time were stored.

This incident is in vliesseparierten cell electrolyte from the fleece herausgedrückt. The electrolyte fills existing free spaces and can in Extremfall at Wiederaufladung through the valve of an aerosol exit. In any case, such operating conditions favor enhanced stratification that have the known disadvantages such as non-uniform loading of the electrodes on the level and therefore local mass overuse with Ausschlammung and increased grid corrosion.

Starting from this prior art, the invention aims to provide an electrochemical cell generic type, in which the disadvantages mentioned are avoided or minimized.

The solution to this problem is defined in claim. 1 Advantageous further developments are indicated in the dependent claims.

In the Strukturscheider is it a formstabilen, especially quaderförmigen body the entire space between the electrodes filled to which the for discharges necessary electrolytes record and set to and the degassing of the electrodes gewährleistet, mechanical pressure, in particular at Unterdruck occurs in the cells that can resist and a pore system, which avoids the stratification largely.

The mechanical strength of the structure separator causes a pressing of the mass of the lattice of the pasted grid electrodes. The mechanical fixing grids and mass are held in intimate contact, as it is only possible with more sophisticated tube electrodes, whereby the cyclic stability of tube cell designs can be achieved even when pasted grid electrodes.

Another advantage of the inventive design results, the minimum pressure of formschlüssige Plattensatzes during manufacture of Plattensatzes on commonly accepted Fertigungsanlagen unlike with vliesseparierten cells, where up to 35% of Vliesvolumens be compressed.

The fillable acid pore volume of the structure separator is maintained throughout the period of use and resistant to acid. This makes the refill of verlorengegangenem in the process water, which causes a concentration of the sulfuric acid, are possible. Not so with gel and fleece.

Here varies over time and with the operating conditions, the fillable pore volume. In particular, the gel this change is largely irreversible. These changes also lead to changes in the overall performance. The structure Scheider but forms together with the electrodes a holistic, sustainable microporous system.

According to the invention constructed electrochemical cells reach a minimum standard cycle life, but compared with the prior art, significant advantages are achieved.

The invention is explained with reference to a schematic drawing.

It shows:<dl id="dl0001"><dt>figure 1</dt><dd>a set of plates with a structure Scheider invention in view;</dd><dt>figure 2</dt><dd>one arranged in an electrochemical cell plate set fragmentary end view.</dd></dl>

The electrochemical cell, especially as a component of an accumulator consisting of a vessel 1 having a built-in disk set having at least one plate 2 as a negative electrode and a plate 3 as the positive electrode and between the plates arranged structure separators 4. In the vessel is electrolyte, in particular sulfuric acid electrolyte , defined in the electrodes and in the structure of separators. The structure separator 4 serves as a separator, the structure separator 4 is dimensionally stable, insulating, porous and absorbent.

The plates 2,3 are designed as grids, the structure Scheider 4 area applies to the surfaces of the separated plates 2,3 in the Einbausollage itself.

A merger of the active materials is controlled and limited by the structure Scheider. The structure separator 4 may be made of suitable plastic material or also of an inorganic material or a mixture of both. In the manufacture of plastic material the porosity can be produced by introducing a pore-forming agent. The separator structure may consist of a single, or several identical or different layers.

Preferably at large electrode surfaces, the structure Scheider 4 outer surfaces Entgasungsbereiche, for example, narrow grooves or the like structures by means of which a reliable degassing of the plates is 2.3 guaranteed, but is only an insignificant effect on the discharge characteristics. The large area of ​​contact of electrodes and structure Scheider is essentially retained. The separator structure 4 preferably has a pore distribution such that 80% of the pores have an average diameter of 0.05 to 20 microns, but preferably a diameter of 0.2 to 8 microns.

By the present invention constructed electrochemical cell with the structure of separator 4 according to the invention it is achieved that the entire space between the plates is 2.3 filled by the structure of separator 4, wherein the structure separator receives and determines the majority of the time required to discharge electrolyte. By appropriate structuring of the structure separator 4 also degassing of the electrode plates is ensured. The system can the normally occurring mechnischen pressure, in particular a vacuum which occurs in the cell resist. Through the pore system of the structure separator also acid stratification is avoided.

It is also the replenishment of decomposed or vaporized Elektrolytwasser easily possible, the electrolyte even after refilling the Strukturscheider 4 festgelegt is.

The invention is not limited to the Auführungsbeispiel, but in the context of the disclosure often variable.

All new, disclosed in the description and / or drawing of single and combination features are considered essential to the invention.