Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Patent
1985-06-26
1988-06-07
Skapars, Anthony
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
429239, 429241, 429245, H01M 424, H01M 476
Patent
active
047496355
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a plate electrode comprising a metallic covering which is intended for use in alkaline electrochemical elements, such as, for example, nickel/cadmium accumulators.
In comparison with plate electrodes for acidic electrochemical elements, for example lead accumulators, the coverings differ both with respect to the material and, abov all, with respect to workability and form (metal fabrice).
The cover-walls of known pocket plates of this type consist usually of perforated metal sheet, for example, of nickel-plated sheet iron. The mostly elongated pockets are produced individually from perforated metal strips and, when the active composition has been filled and closure has been effected by mutual attachment at the longitudinal edges, --for example, by interlocking seams, --are assembled to form a pocket plate. The pockets which are located horizontally above one another, as a rule, are joined by metal borders at the side edges of the pocket plate and a metal crosspiece, comprising a conduction lug, joins the lateral metal borders at the upper edge of the pocket plate.
The production of this type of pocket plate is rather costly owing to the numerous operations, both as regards the mechanical equipment required and the volume of work. It is well-known, however, that pocket plates of this type also have qualitative shortcomings, for example, low utilisation of composition, high internal resistance, high transition resistance between active composition and electrolyte, inadequate conduction of the current of the conduction lug and low power to weight ratio, by comparison with other electrode types, for example, sintered plates.
French Pat. No. A 2,347,790, in the name of VARTA Batterien AG, Federal Republic of Germany, of Nov. 4, 1977, claims alkaline electrochemical elements. All that is being said about the positive electrodes is that the positive composition is enclosed under pressure in a metallic fabric, preferably nickel fabric. Nothing further is specified regarding the design and/or production of the electrode mentioned.
The object of the invention is to provide a plate electrode, suitable for the purpose indicated, which is easier and cheaper to produce than conventional pocket plates and sintered plates and possesses improved quality features by comparison with the latter, particularly by comparison with pocket plates.
The invention also relates to a process for the production of this type of plate electrode.
Owing to the use of metal fabrics in place of perforated metal sheet for the cover-walls, the passage crosssection per unit area can be increased approximately threefold and more. This makes better utilisation of the active composition possible and leads to a lower transition resistance between active composition and electrolyte. This also achieves a higher discharge voltage. The current is conducted directly to the conduction lug via the wires of the metal fabric pieces, that is to say, independently of the orientation of the pasted squares, which disposes of the transition resistances, which are inevitable in the case of known pocket plates and frequently change with time, between the pockets and the metal borders. This results in a lower internal resistance whose magnitude, moreover, remains virtually constant. Besides, no metal borders are required.
The metal fabric pieces consist preferably of uniform uncoated wire material, for example of nickel wire. This avoids contamination of the active composition with iron, which occurs on the known pocket plates comprising cover-walls made of nickel-plated sheet iron, and results in an increase in the cycle durability.
Since metal fabric is lighter than perforated metal sheet, a reduction in weight and therefore a higher power to weight ratio of the electrochemical elements, equipped with it, can also be achieved by means of the plate electrode according to the invention.
The plate electrode according to the invention is much easier to produce and with less expensive means, since there is no prefabrication and assembly of indiv
REFERENCES:
patent: 2251913 (1941-08-01), Brennan
patent: 3023262 (1962-02-01), Emmerling et al.
patent: 3560262 (1971-02-01), Baba et al.
patent: 4221854 (1980-09-01), Hammar et al.
patent: 4223081 (1980-09-01), Faber
patent: 4237205 (1980-12-01), Matter
patent: 4356242 (1982-10-01), Doniat
patent: 4439916 (1984-04-01), Faber
Kolling Heinz
Muller Max
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