Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Reexamination Certificate
1998-07-17
2001-01-23
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
C429S225000
Reexamination Certificate
active
06177212
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the improvement of a method for producing a valve-regulated lead-acid battery.
2. Description of the Related Art
In order to cope with the recent development of multimedia system, infrastructural improvements in the optical communication network corresponding thereto have been progressing rapidly. An optical communication fiber system is capable of communicating a large amount of data but requires the conversion of optical signal to electrical signal at connecting points. The optoelectronic converter used for this purpose cannot operate without backup power supply against power failure. These converters are mostly used outdoors. Thus, this type of a valve-regulated lead-acid battery used as backup power supply is exposed to very severe temperature atmosphere. In particular, in a high temperature atmosphere in summer time, the storage battery is liable to “dry-up” or “thermal-runaway” due to decomposition of the electrolyte during float charging and thus exhibits impaired battery properties.
The foregoing dry-up which occurs during float charging is a phenomenon in which decomposition causes the electrolyte to lose water content, reducing the discharge capacity of the battery. The foregoing thermal-runaway is a phenomenon in which the rise in temperature is accompanied by the rise in charging current that causes abnormal heat generation of the battery, eventually resulting in dry-up that disables the battery. These phenomena, particularly thermal-runaway, can easily occur when the battery is used at a temperature as high as not lower than 60° C. over an extended period of time. When the battery is used at a temperature as high as not lower than 70° C., these phenomena can occur even in a short period of time. It has thus been desired to develop a battery which can be used in such severe conditions.
The valve-regulated lead-acid battery which is little liable to these phenomena is a battery which shows little rise in float charging current even when used at high temperatures. Such a battery cannot be obtained by the conventional art.
The rise in charging current accompanying the temperature rise is a synergism of the rise in the amount of oxygen produced at the positive electrode by the decomposition of the electrolyte with the rise in the oxygen absorption reaction rate at the negative electrode accompanying the enhancement of the oxygen recombination reaction rate. When the rate of generation of Joule heat accompanying the rise in the reaction heat and charging current becomes greater than the rate of heat dissipation from the battery, the battery temperature rises beyond the ambient temperature. The rise in the battery temperature causes a further rise in charging current that causes a further rise in the battery temperature. Thus, a vicious circle arises, eventually resulting in thermal-runaway.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a valve-regulated lead-acid battery which hardly occurs thermal-runaway even if it is used at high temperatures.
The present invention provides a valve-regulated lead-acid battery produced by a so-called container formation method which comprises the steps of: preparing a battery from unformed positive and negative plates, filling a predetermined dilute sulfuric acid into said battery, and then applying an electric current to said battery so that the group of plates is formed in a battery case, wherein a negative active material comprising an oil incorporated therein is used. In accordance with the present invention, a valve-regulated lead-acid battery having stable battery properties which shows no rise in float charging current even at high temperatures can be provided.
According to the present invention, a valve-regulated lead-acid battery having stable battery properties which shows no rise in float charging current even At high temperatures can be provided.
DETAILED DESCRIPTION OF THE INVENTION
Detailed description of the present invention will be described as follows.
The valve-regulated lead-acid battery according to the prevent invention concerns a valve-regulated lead-acid battery produced by a so-called container formation method which having the steps of preparing a battery from unformed positive and negative plates, filling a predetermined dilute sulfuric acid into said battery, and then applying an electric current to said battery so that the group of plates in formed in a battery case, wherein an negative active material comprising an oil incorporated therein is used. The addition of the oil is effected during the kneading of the negative electrode paste. The amount of the oil to be incorporated is preferably from 0.05 to 1% by weight. Referring to the kind of the oil to be used, animal oils and vegetable oils may be used. However, paraffinic oils, naphthenic oils, olefinic oils, aromatic oils and silicon-based oils are preferably used. Commercially available oils contains various additives incorporated therein. Oils comprising ordinary lubricants and corrosion inhibitors incorporated therein in a proper amount may be used.
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patent: 4888259 (1989-12-01), Ebner
patent: 5403462 (1995-04-01), Lev
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Kamada Akira
Kosai Masahiko
Chaney Carol
Japan Storage Battery Co., Ltd.
Ruthkosky Mark
Sughrue Mion Zinn Macpeak & Seas, PLLC
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