Types of accumulator batteries
The most commonly used in mobile phones and radio communications are the following types of batteries:
• nickel-cadmium (Ni-Cd)
• Nickel-metal hydride (Ni-MH)
• Lithium-ion (Li-Ion)
• Hermetic Lead-Acid (SLA)
• lithium polymer (Li-polymer)
Different types of batteries have not only different cost, but also differ in the main parameters: the number of cycles of recharging, the maximum shelf life, the capacity given, the size, the temperature range of work, the possibilities of accelerated charging, etc.
Batteries are executed both in the form of one element, as well as several, sequentially included and decorated in one case elements - batteries. Some battery models include electronic controls that control charge mode and protect the battery from malfunctioning.
As a rule, each manufacturer uses the original production technology, and, accordingly, their own designs on the design of those or other models. Nevertheless, there are several general approaches to the design of different types of batteries.
For example, a lead acid battery consists of, as a rule, two plates (electrodes), placed in an electrolyte (aqueous solution of sulfuric acid).
In the nickel-cadmium element, the negative and positive plates are rolled together and placed in a metal cylinder. The positive plate consists of nickel hydroxide, and the negative - from cadmium hydroxide. The two plates are insulated with a separator, which is electrolyte-moistened.
Nickel-metal hydride battery is constructively similar to nickel-cadmium battery, but has a different chemical composition of the electrolyte and electrodes. In a lithium-ion battery, electrodes and a separator (separator) are placed in an electrolyte of lithium salt.
Capacity expressed in ampere-hours (A • h, mAh) or watt-hours (W / h) is the amount of energy that the battery can give to the load in one hour.
In practice, the battery capacity is usually measured by the battery analyzer. For example, a battery with a nominal capacity of 1200 mAh gives a load of 1200 mA for one hour.
According to the idea, the energy consumption in the shorter time should be the same as in the case of a slower discharge, since the same amount of energy is given, only for a shorter time - but in practice this is not the case, mainly because of the final value of the internal resistance of the battery . When discharging the battery installed in the analyzer, which allows you to adjust the different discharge currents, higher energy will be given in the event that the battery is discharged by lower current.
Nickel-cadmium (Ni-Cd) batteries
Nickel-cadmium batteries are manufactured in different countries around the world since about 1950. To date, more than 50% of all portable accumulators are nickel-cadmium.
The main advantages of this type of battery are:
• low cost;
• high resistance to temperature fluctuations;
• good resistance to large currents of charge and discharge, since small internal resistance allows large currents to pass (other types of batteries do not suit it);
• large number of "charge-discharge" cycles.
Among all types of batteries, nickel-cadmium is the only one that bestows the maximum capacity, provides a large number of charge cycles, discharge, if periodic deep discharges occur (up to 1 V per element).
Disadvantages of Nickel-Cadmium Battery:
• the presence of so-called "memory effect";
• This type of battery is environmentally contaminated, since cadmium is a highly toxic substance. Also, there are additional problems with its processing;
• relatively low specific capacity, although not in all cases it is critical.
Nickel-metal hydride (Ni-MH) batteries
Known in the market since the late 80's. The impetus for the development and production of these batteries appeared, mainly, their higher energy density compared to Ni-Cd.
Some of the distinctive advantages of today's Ni-MH battery as compared to Ni-Cd:
• high specific capacity (with the same overall dimensions of the capacity of 30% more), less weight;
• less prone to "memory effect";
• The battery contains less toxic metals and is currently considered environmentally friendly.
Unfortunately, the Ni-MH battery also has drawbacks over the Ni-Cd battery, namely:
• has a much smaller number of discharge cycle cycles;
• The Ni-MH price of a battery is higher than Ni-Cd, although it may not always be a major problem if the user prefers a small size and weight;
• The operating temperature is lower than that of the Ni-Cd battery.
• Compared to Ni-Cd and Li-Ion batteries, the Ni-MH battery has the lowest load capacity - it can not handle large currents;
• This type of battery is afraid of deep discharges, because the battery life is directly related to the discharge depth;
• self discharge is more than 1.5 times higher than that of a Ni-Cd battery, which is an important parameter when storing;
