Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Reexamination Certificate
1998-03-13
2001-10-09
Bruillette, Gabrielle (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
C429S225000, C429S226000, C429S233000, C429S234000, C429S237000, C429S218100, C429S220000
Reexamination Certificate
active
06300014
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a new lead-antimonytin-arsenic alloy for use in the production of grids employed as holders of the positive electrodes in electric accumulators, preferably lead-acid accumulators.
The electric accumulators which include positive electrodes, provided as holders of the grids constituted by the new alloy in compliance with the invention, has an improved behaviour against corrosion at high temperatures.
At present, electric accumulators are required for use in motorcars with special cycling characteristics, corrosion strength and improved behaviour at high environmental temperatures. The same may be said of the batteries used for storage of power and photovoltaic applications.
As is known, lead accumulators are made up of lead dioxide anodes and sponge lead cathodes, said electrodes having been prepared as from holders or grids of equal or different alloys and with different lead sulphate compositions included into the active material. These electrodes are physically separated by a separator of a different type of material (cellulosic, plastic, glass fibre, . . . ) the purpose of which is to provide a passage of conductor ions from one electrode to another, without any physical contact with each other.
Lead alloys are described in different patents for use in batteries, with corrosion strength properties. Thus, U.S. Pat. No. 5,339,873, describes the inclusion of titanium in order to improve the corrosion strength, or of tellurium in WIPO Publication No. WO90/09462. Other European and American patents describe the use of grids of different lead alloys with the addition of silver or strontium and a low tin content (EP 0506323 A1; U.S. Pat. No. 5,298,350; U.S. Pat. No. 5,434,025; U.S. Pat. No. 4,137,378 as improved alloys for lead-acid batteries. Similarly, U.S. Pat. No. 3,078,161 mentions an alloy made up of lead-tin with silver and cobalt, free from antimony.
SUMMARY OF THE INVENTION
The studies carried out by the applicant body on high temperature resistant power accumulators have given rise to a type of alloy with good service during cycling of up to 80° C., preferably in the interval of 20 and 80° C. and more preferably between 40-80° C. This is obtained according to the invention with antimony and tin alloyed lead grids, which are preferably used in positive plates of the lead-acid accumulators.
Consequently, according to a first aspect, the present invention provides electrodes, preferably positive, produced by means of a continuous or discontinuous process, and provided as holder, of a grid based on a lead-antimony-tin-arsenic alloy, which may also be obtained by means of a continuous expansion process, in the form of metallic strips obtained by casting.
According to a second aspect, the present invention offers a new lead-antimony alloy with a high tin content, for grids produced in a continuous or discontinuous manner to be used in positive electrodes of electric accumulators, the alloy of which is corrosion inhibiting and is provided with an optimum arsenic, copper and bismuth content so as to improve the mechanical properties.
According to a third aspect, the present invention provides a lead-acid accumulator battery provided with positive electrodes such as those previously indicated, which may be used under cycling conditions both at high and at low temperatures. Said battery, according to the invention, due to its use in facilities which may be exposed to high temperatures, may involve or not, a sealed battery, which presents a low water consumption, without requiring that this consumption be zero, but which, since it is very low, makes the accumulator not require any water to be added throughout all its service life.
In compliance with this invention, the inclusion of a high tin content to the alloy of the supports of the positive electrodes, is more beneficial versus the possible coating with corrosion inhibiting alloys, due to the fact that the manufacturing costs are not increased by new processes. Additionally, the behaviour against corrosion in sulphuric acid of the new alloy according to the invention is greatly improved, in comparison to the alloy with a low tin content.
Specifically, the present invention provides a new lead alloy as grid to be used as support of the positive electrode in a lead-acid accumulator battery, characterized in that it comprises as alloy components with the lead;
from 1 to 5%, preferably from 1 to 3% and in particular from 1.2 to 2% of antimony;
from 0.5 to 3%, preferably from 0.5 to 1.5% and in particular from 0.9 to 1.3% of tin;
from 0.05 to 0.50%, preferably from 0.10 to 0.25% of arsenic.
from 0 to 0.0500%, preferably from 0.0100% to 0.0300% of copper; and
from 0 to 0.0200%, preferably from 0.0050% to 0.0100% of bismuth.
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patent: 3912537 (1975-10-01), Peters
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patent: 5558960 (1996-09-01), Mitchell
patent: 5593797 (1997-01-01), Brecht
patent: 0506323A1 (1992-02-01), None
patent: 2010905A (1978-12-01), None
patent: 2010905 A (1979-07-01), None
patent: 2197342 A (1988-01-01), None
patent: 2197342A (1988-05-01), None
patent: 61164332 (1986-11-01), None
patent: 63019768 (1988-01-01), None
Sainz Mayoral Maria José
Soria Garcia-Ramos Maria Luisa
Trinidad Lopez Francisco
Bruillette Gabrielle
Darby & Darby
Martin Angela J.
Sociedad Espanola del Acumulador Tudor, S.A.
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