Щелочные аккумуляторы

Comparison of asymmetric current parameters influence on nickel-cadmium accumulators forming time is performed. According to the results of capacity forming of NKM-22 accumulators with thin pressed cadmium and metal-ceramic electrodes, the perspective of application of asymmetric current with parameters chosen during experiments and used in this paper is established. Waveforms giving the biggest increase of capacity comply with the most economical parameters defined om models during experiments.

It is shown from analysis of charging current and voltage change on the terminals of sealed Ni-Cd battery at thermal runaway, that thermal runaway is accompanied by a new high-power electrochemical reaction, going at battery voltage of approximately 0.55 V.

For nickel-cadmium batteries of stationary application, a global empiric correlation C(i) describing the dependency of released capacitance by the batteries at different discharge currents was suggested, which is true for batteries of any capacitance and any mode of discharge (H, M, L). The global correlation C(i) can be described by generalized Peukert's equation, Korovin-Skundin's equation, probability integral, and porous electrode equation with accuracy sufficient for practical application.

The comparative results of nickel cadmium storage batteries capacity regeneration with asymmetrical and direct currents after their exploitation on the electric locomotives in the conditions of constant floating with current impulses are represented. The capacity regeneration with asymmetrical current was carried out rapidly, the battery was restored with charging capacity numerically equal to 1.2C_nom.

It is shown by experiments that probability of thermal runway in nickel-cadmium batteries with sintered oxide-nickel electrodes is higher, than in the batteries with extruded and pasted electrodes. Besides, it is shown that the probability of thermal runaway decreases with decrease of battery capacitance.

Electrochemical activity of anodes on the basis of a nickel mesh grid for water electrolysis is investigated. Activation of anodes was made by three ways:
1) chemical covering sulfur-containing compounds of nickel and iron;
2) immersing in solution Na₂S₂O₃ + H₂SO₄ (till pH=3);
3) immersing in solution Na₂S + H₂SO₄ (till pH=3).

Electrochemical activity of cathodes with Pt or Pt-Pd-electrocatalysts was studied by voltammetry method under galvanostatic conditions. The dependence of the overvoltage of hydrogen evolution reaction on the logarithm of current density and on the test time of the cathode with Pt-Pd-electrocatalysts are defined. It is shown that the electrochemical activity of cathode with Pt-Pd-electrocatalyst is two times higher than with Pt-electrocatalyst at the hydrogen evolution reaction in 30% KOH solution at 90°C.

The results of nickel-cadmium accumulators formation with asymmetric current, in the mode providing long life of the first cycle till the accumulator stress stops to grow, are represented. The possibility of using stress on the accumulator as criterion of charge completion is proved. Research shows efficiency of mode applying chosen criterion – consedirable decrease of charge-discharge cycles of formation while preserving given working characteristics.

It was shown by experiments for SAFT batteries of stationary application and medium rate of discharge, that empirical equations Korovin-Skundin's, Peukert's generalized equation, probability integral, porous electrode equation allow to describe the dependence capacitance C(f), given by nickel-cadmium batteries, from discharge current with the accuracy sufficient for practical needs (5-6%) on all the range of discharge currents.

Comparison of influence of asymmetric current parameters on nickel-cadmium accumulators formation process time is carried out. According to the results of capacity formation of accumulators types NKPLHC-0,5 with thin extruded electrodes, we established good perspective for application of asymmetric current with parameters chosen during experiments and applied in this paper. Current waveform which gave the biggest capacity increase, has long charging impulse and short, with wide range, discharge impulse.