RU2258980C1 - Lead cell designed for operation at sub-zero temperatures and method for its charging - Google Patents

Abstract

FIELD: electrical engineering; lead-acid cells and batteries of intermediate discharge class.

SUBSTANCE: proposed cells and batteries are of intermediate discharge class M according to up-to-date International Classification. Novelty is that active material of negative plates is doped with activating additive incorporating 2.5 to 3% of antimony, 0.4 to 0.5% of calcium oxides, and 0.07 to 0.08% of tin from total amount of negative-plate active material. Proposed method for charging the cell includes charge with current amounting to 110% of its value at five-hour discharge, ratio of end voltages at extreme sub-zero and super-zero temperatures being 1.15. Cell is charged prior to placing it in operation at normal temperature for 5 h with current equal to 110% of its value at five-hour discharge, then with 55% of this current.

EFFECT: enhanced output capacity of cell and battery assembled of such cells at low ambient temperatures after pre-charge and discharge at low electrolyte temperature.

4 cl

Description

The present invention relates to the field of chemical current sources, in particular to lead acid batteries operating at low outdoor temperatures with average discharge currents and a high degree of repeatability of charge and discharge cycles.

One of the serious drawbacks of lead batteries of the middle class of discharge, usually referred to in the technical literature as traction, as well as of other types of acid batteries, is their low capacity return after charging and discharge at low temperatures (up to -40 ° С), which is aggravated by freezing of the electrolyte in their the discharged state, and sulfation of the active masses of the electrodes, which ultimately leads to a sharp decrease in the battery life. This phenomenon especially applies to wagon batteries because of their long sludge regime during discharge at the points of turnover of passenger cars in the cold season in the northern and eastern regions of the country.

It is known from technical and specialized literature that a decrease in capacity during the charge and discharge of acidic batteries is associated with an increase in the viscosity of the electrolyte, which worsens its access to the pores of the active masses. To eliminate this phenomenon, it is necessary to increase its temperature due to additional energy (internal or external) when charging batteries. The patent and technical literature describes a number of technical solutions aimed at eliminating this defect. In particular, it is proposed the use of a different series of electric heaters placed inside or inside the batteries (V. Bolotovsky and others. Operation, maintenance and repair of lead batteries, L .: Energoizdat, 1988). The use for this purpose of auto-heating by discharging the batteries to rheostats to a greater extent reduces the useful capacity of the batteries and shortens their service life in comparison with an increase in the capacity return from heating the electrolyte. Other methods and means have also been proposed that are similar in technical essence to the above. Such as, for example, the use of preheated air or exhaust gases in diesel vehicles as a heat heater (A. Rusin et al. “Chemical current sources”, L .: Energoizdat, 1987, p.23-31).

Other groups of methods for increasing electrical characteristics at low temperatures are known, based on the use of various additives in the active masses or electrolyte of lead batteries. However, the effectiveness of a wide variety of products (Tanning agents No. 4, BPS, BKF, humic acids, sodium and potassium diosulfates) was extremely low, which could not ensure the normal operation of the batteries at temperatures down to -40 ° С. It is known to use fluorine-surfactant additives in the active masses of electrodes and electrolyte in order to reduce the viscosity of the electrolyte at low temperatures and improve the discharge characteristics of starter acid batteries ("A method for ensuring the electrical characteristics of lead batteries at low temperatures" - patent RU 2184409 class H 01 M 10/12 ) The use of these fluorine-surfactants additives in lead-acid batteries is implemented in various ways, including through their use in the technological process of manufacturing batteries. The introduction of fluorine-surfactant additives somewhat increases the return on capacity when discharged at negative temperatures for acid-based batteries of the smeared type when charged with warm electrolyte, and discharge at negative temperatures of the electrolyte. For wagon batteries, as well as for batteries of the entire rolling stock, the charge passes almost at the electrolyte temperatures corresponding to the ambient temperature. Considering also the cross-country ability of passenger cars on all main railways Russia and the CIS, the introduction of additives will almost increase the return on capacity by only 1-2% with a significantly complicated technology for the production of lead batteries for rolling stock railway.

The inefficiency of the known methods and devices for increasing the capacity of acid lead batteries of the middle class of discharge in relation to their use on passenger cars required the search for new ways to increase their capacity when charging at low temperatures.

First of all, the search for activating chemical components to enhance the intensity of the oxidation (charge) reaction was carried out in combination with variations in the charging current and voltage, including a change in the initial electrolyte density when preparing the batteries for operation. Experiments were carried out to introduce various components into the traditional chemical composition of lead and antimony electrodes, namely, calcium and tin oxides, and also to introduce antimony not only into the electrode lattice, but also into their paste (active masses).

As a result of checking the final characteristics of prototypes of lead-acid batteries with different percentages of the ratio of the listed components and increasing the level of charging voltages (up to 15% with respect to generally accepted values at negative temperatures), the following was established. Introduction to the total volume of active masses from 2.5% to 3% antimony, and from 0.4% to 0.5% calcium oxides and from 0.07% to 0.08% tin and about 96% lead in relation to the whole the active mass of negative electrodes, while providing a stable current value of 110% of the five-hour discharge current (77A for the set charge current for most types of passenger cars in Russia) provides a charge for 5-6 hours at an ambient temperature of -40 ° C and the initial electrolyte temperature -30 ° С when charging with a current of 70A to a final voltage of 2.7V increase in capacity 35-40%.

During the experimental verification of the given capacitance under these conditions, the magnitude of the given capacitance in experimental PzS350P lead batteries with positive shell-type electrodes increased to 40% of the nominal. In this case, the active masses were obtained by preparing them both dry and wet after preliminary grinding to a high degree of dispersion of lead and all components.

Bench studies also carried out for lead batteries with a capacity of 350Ah type PzS350P with positive armored type electrodes and a new composition of active masses in a negative electrode of a smeared type while providing a charge of 77A until a final voltage of 2.35V per battery is reached at positive temperatures (up to + 40 ° C) provided the return of capacity at a discharge current of 60A - 300 ÷ 340Ah (90% Cn).

The capacity return after a similar charge and discharge of the experimental batteries to a final voltage of 1.7 V (per battery), but at an external temperature of -20 ° C, was 300 Ah, i.e. more than 80% Cn, while the density of the electrolyte of discharged batteries (up to a voltage of 1.8 V) was 1.245-1.26 g / cm ³ , which virtually eliminates its freezing and provides a long mode of car stagnation without battery failure, without the necessary frequent her recharges.

The obtained experimental data show that, in contrast to all known types of lead acid batteries, in particular, with a shell-positive electrode with a traditional active chemical composition, the introduction of additives from these components at their high dispersion, along with an increase in the charging voltage at extreme negative temperatures, make it possible to increase their capacity is 35-40%, which ensures a high electrolyte density after their deep discharge at low temperatures .

Field tests of a large batch of advanced PzS350P batteries on passenger cars, such as 61-4179 built by the Tver Carriage Works, which have been in real operation in the Southern and Northern directions for two years, have shown their stable operation while ensuring full power supply to all electric consumers without limiting their operating time ( discharge) both in flights and in sludge points, when the outdoor temperature changes from -45 to 45 ° C. In this case, a one-time preliminary charge cycle before installation on cars with a current of 77A for 5 hours (110% of the value of its 5-hour discharge current), and then 30A for 5 hours (55% of the value of its 5-hour discharge current) provided a set of nominal battery capacity. Changes in the initial electrochemical indices on no operating battery took place after two years of regular operation. At the same time, the operation of batteries with a high electrolyte density in the region of extremely low temperatures precluded the possibility of another important drawback of lead batteries - sulfation of the electrodes, which previously led to mass failure in the northern climatic zones of Russia in 2-3 years of operation. Providing a low level of charging voltages on wagons during the summer period of operation excluded the frequent replenishment of new type batteries with distilled water, and also reduced the energy consumption for their charge. The development and research carried out made it possible for almost the first time to use the cheapest and most powerful lead batteries in the entire fleet of passenger cars operating in all climatic zones of Russia, while at the same time reducing the operational costs of their maintenance and purchase by railway units.

Claims (4)

1. Lead acid battery for operation at low temperatures, consisting of positive and negative electrodes based on a support grid of lead alloys and active masses pressed onto it in the form of a lead paste with activating substances, separators and electrolyte, characterized in that in quality activating substances used antimony, calcium oxides and tin in the ratio to the total volume of the paste of negative electrodes, respectively, from 2.5 to 3%, from 0.4 to 0.5% and 0.07 to 0.08%. 2. The lead battery according to claim 1, characterized in that the active mass paste of all components of the positive and negative electrodes is pre-crushed to a finely dispersed state of the particles, followed by dry mixing. 3. The method of charging a lead battery according to claim 1, characterized in that the charge in operating conditions on the vehicle passes a constant current value of 110% from its value of a five-hour discharge current to the value of the final voltage with a ratio of its value at extreme negative ambient temperatures to it value at extreme positive ambient temperatures of 1.15. 4. The method of charging a lead battery according to claim 1, characterized in that the cycle of its charge before commissioning is carried out at normal ambient temperature for 5 hours with a current of 110% of its five-hour discharge current, and then with a current of 55% of the current value of its five-hour discharge.