Globe-union Inc.

Lucent Technologies Inc.

Norma K Bullock

Wen-Hong Kao

Ralph A Petersen

Douglas G Fent

James S Symanski

Roy Kuipers

Trung Van Nguyen

A temperature sensing device for permanently indicating when a product is exposed to ambient temperatures exceeding a maximum permitted temperature of the product for a time period long enough to permanently damage the product. In an exemplary embodiment, the temperature sensing device is typically located on the protective cover of a battery away from terminals and the battery casing. The temperature sensing device is made of a material to permanently expand and/or shrink upon reaching critical temperatures (e.g. too hot). The expansion is visually detectable by means of a visual indicator and/or reference point.

Temperature sensing device for permanently indicating when a product is

In an arrangement for charging a battery in a battery plant, a resistive network is situated in the charging path of a battery being charged to guarantee a minimum total resistance of the added resistance and the battery's internal resistance regardless of the thermal effect of reducing the battery's internal resistance. A diode path bypasses the resistive network during discharging of the battery to reduce power dissipation. Charging current is controlled in response to a temperature of a heat sink on which the resistive network is mounted. Ambient temperature is used as a control or in another arrangement as a controlling factor in controlling charging current. Battery temperature may also be used as a control or in another arrangement as a controlling factor in controlling charging current.

Battery protection circuitry for limiting charging parameters of a

A battery charging system controls and modifies the output voltage of the charging rectifier in response to differing temperature ranges of the battery. At a low range of temperatures starting at a low temperature (e.g. within a range of 0 to 25.degree. C. to about 53.degree. C.) the rectifier voltage decreases as the temperature increases to prevent charging current from rising as the battery temperature increases. This change is performed in accord with a linear graphical slope relating the change of charging voltage to temperature. A suitable charging voltage decrease rate may be 3 mV/.degree. C./cell with a range of 1.5 mV/.degree. C./cell to 5 mV/.degree. C./cell being acceptable. Reduction of the charging voltage within this range reduces the aging effect of high temperature operation of the battery. The charging voltage applied to the battery is held at a constant value over a subsequent range of temperatures (e.g. 53.degree. C. to 75.degree. C.) in order to prevent accelerated grid corrosion within the battery, which normally occurs as the voltage approaches the fully charged open circuit voltage level of the battery. At attainment of a high threshold temperature at the high end of the second temperature range (e.g. 75.degree. C.) the charging voltage level is dropped as a step function to a level below the fully charged open circuit voltage threshold of the battery to arrest the thermal runaway situation. At this level the battery is maintained at partial, but not full, state of charge by the rectifiers, and an alarm signal is generated to alert the maintenance staff to this situation.

Apparatus and method for controlling a charging voltage of a battery

A thermocell includes a negative electrode, such as a lead-acid electrode, and a porous oxygen (air) electrode disposed in a housing and separated by a separator. During discharge, oxygen is allowed to permeate through the oxygen electrode and separator to reach the negative electrode. Chemical oxidation of the negative electrode by oxygen in the presence of sulfuric acid yields water, lead sulfate, and heat. The heat can be used in many ways, such as warming up an adjoining automotive battery in winter, or as a personal heating pad. The heating rate is controlled by the rate of oxygen ingress. When not in use, the oxygen electrode is sealed by taping or by other means to stop ingress of oxygen. The used thermocell can be recharged by charging the negative electrode while evolving oxygen at the oxygen electrode.

Thermocell

An electrode suitable for use as a lead-acid battery plate is formed of a paste composition which enhances the performance of the plate. The paste composition includes a basic lead sulfate, a persulfate and water. The paste may also include lead oxide and fibers. An electrode according to the invention is characterized by good strength in combination with high power density, porosity and surface area.

High performance positive electrode for a lead-acid battery

The present invention provides a method for maintaining the specific gravity of acid in a lead-acid battery within a predetermined range to prevent undesirable plate degradation and gassing during storage. Extended shelf-life is accomplished by employing a battery which is formed to the desired voltage and which is stored in a damp condition with the electrolyte maintained in a range which, in the most preferred embodiment, is between about 1.015 and 1.320. A desiccant, for example a gelled sulfuric acid desiccant, is placed in the battery housing, out of contact with the plates, to absorb the water vapor which is generated by the self-discharge reactions. The amount of desiccant is selected so that all the water vapor formed during such reactions is removed to maintain the specific gravity of the electrolyte in said range. Extended shelf-life results, and the desiccant can be used to form the battery electrolyte at the time it is desired to place the battery in service.

Extended shelf-life battery

Improved formation efficiencies for positive pasted plates used in lead-acid batteries are provided by treatment of the positive plates with a stabilized aqueous alkaline persulfate solution to effect the conversion of lead monoxide to lead dioxide. Use of the alkaline persulfate solution enhances both formation and initial performance of the fabricated batteries. A stabilizing agent is added to the alkaline persulfate solution to stabilize the lead sulfate and basic lead sulfates in the paste. A preferred method for producing positive plates of a lead-acid battery comprises the steps of (a) heating the pasted plate, (b) spray coating with or dipping the plate in a persulfate solution, and (c) reheating the plate to accelerate the reaction of lead monoxide with persulfate to form lead dioxide. The persulfate treatment may be applied to uncured pasted plates and used with plate paste containing free lead, and the spray-coating procedure offers an easy and efficient manufacturing step.

Method of treating a battery electrode with persulfate

A process for coating a solid substrate with a layer of barium metaplumbate includes steps of forming a layer of lead oxide on the substrate, if not already present, and then reacting this layer with a barium salt at an elevated temperature to form a layer of coating of barium metaplumbate. Reaction temperature is a key aspect of this process, along with use of a barium salt which will react at the temperature selected. In particular, the reaction temperature must be sufficiently high to allow the reaction to proceed, but lower than the melting point of the substrate. The described process eliminates the need to preform BaPbO.sub.3 prior to coating and can be conducted at a much lower range of temperatures than prior processes.

Process for forming barium metaplumbate

An electrode suitable for use as a lead-acid battery plate contains an inorganic metal oxide additive which enhances the formation of the plate. The additive is electrically conductive, stable in aqueous solutions of sulfuric acid, but does not participate in the electrode reaction. Suitable metal oxides include barium metaplumbate and other ceramic perovskite materials having similar properties. The conductive ceramic may also be used in electrodes for bipolar lead-acid batteries and in an electrode, particularly an anode (positive electrode), used in electrolytic processes.

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Pewaukee, WI, United States of America

Norma K Bullock