Types of chemical power sources
Galvanic cells and accumulators belong to chemical sources of electrical energy. In them the chemical eneryogiya of oxidation-reduction processes will be transformed to electrical energy of the direct current.
Without going into detail of the device of chemical sources and the chemical reactions proceeding in them, we will stop on ekspluatatsionyony indicators of their most widespread types.
Manganese-zinc elements with alkaline or salt electrolyte are issued the industry in two constructive versions: stakanchikovy (cylindrical) and in the form of the parallelepiped or the disk (disk). They differ in the small cost, broad temperature range and dlitelyyony storage life.
These elements, as well as all other chemical elements, разового actions.
Mercury-zinc elements have the high mechanical strength, small level of the self-discharge (3-5% in the month), storage life more than 18 months, are harmless to service personnel, but in their production very harmful veyoshchestvo are applied. The cost of these elements is 12-17 times higher, than manganese-zinc.
Copper-magnesium elements because of the big samoyorazryad are applied as reserve. They are put in action by introduction of the special activator just before the upotrebyoleniye. After activation their storage life of less than a day. The discharge of these elements is followed by self-heating that allows them to work at very low temperatures, but activation has to be made at the positive temperature. The cost of such elements is nearly 20 times higher, than manganese-zinc.
Accumulators differ from galvanic cells in the fact that oxidation-reduction processes in them are reversible. Therefore they are suitable for repeated use. Promyshyolennostyyu different types of accumulators which are classified by the form electrolyte on acid and shchelochyony, by material of electrodes on lead, cadmium-nickel, silver-zinc, etc., by the design on lamellar, bezlamelny, pressurized, etc. are issued.
The alkaline cadmium-nickel lamellar (KN) and bezlamelny (KBN) accumulators (opened, not spilled and pressurized) are easy-to-work, have service life of 50-1000 cycles the charge — discharge, have the most vysoyoky mechanical durability from all chemical current sources, the self-discharge does not exceed them 20% in the month, safety in the filled-in state more than two years. These accumulators work with the broad range of temperatures with rather small decrease in udelyyony indicators. The cost of hermetic cadmium-nickel accumulators is almost a hundred times higher, than the manganese-zinc element of the same capacity, but bigger service life reduces power source cost with such accumulator at the long ekspluyoatation.
Silver cells oblayodat the best specific characteristics. However they maintain only 50-100 cycles of the recharge. The self-discharge makes them 5-10% in the month. They remain without electrolyte of 5 years, and with electrolyte only 6 months.Top