The designer of the “batteries” (as they are commonly, although wrongly, referred to), which are still used until this day, is a French engineer Georges Leclanché, who built his cell (as it should be correctly called) in 1866. However, a cell should not be confused with rechargeable batteries, which are available in the same sizes but their principle of operation is different (the difference between batteries and rechargeable batteries will be explained at the end of this text). Since the need is the mother of the invention, the original Leclanché cell , with a rated voltage of about 1.5 V, was used to power telegraphs, bells, and first telephones. Today, after more than 150 years, such batteries are used to power small electrical equipment, i.e. toys, radios, audio players, flashlights, and others. Furthermore, more expensive lithium-based cells are becoming increasingly frequently used in common equipment.
The variety of powered equipment places various demands on the cells in terms of capacity, voltage or short circuit current. This is reflected in their dimensions and shape as well as in the design and type of electrode or electrolyte material used. What are the differences between “batteries” and how to use them correctly?
The disadvantage of the original Leclanché cell was the use of liquid electrolyte. It consisted of a vessel in which a zinc electrode and a container made of porous material were placed. Moist, powdered manganese dioxide mixed with carbon dust was poured into this container, and a carbon rod was placed in it. The outer container was filled with a concentrated solution of ammonium chloride. Manganese dioxide acted as a so-called carbon electrode depolarizer, absorbing hydrogen. Otherwise, the gas accumulated on the surface of the carbon rod would isolate it from the rest of the electrolyte and interrupt the current flow.
The design of the dry version of the cell had a great influence on the convenience of using this type of power supply. This was done in Germany in 1887 by Carl Gassner. He replaced the liquid ammonium chloride solution with a mixture of this salt and damp gypsum dust (nowadays starch glue or silica gel is usually used).
In the course of over 150 years of its development, theLeclanché cell (commonly known as a zinc battery) has undergone many modifications aimed at increasing its durability and capacity. One of the ways to extend the operating time is to add zinc chloride to the cup-filling paste – such cells are called Heavy Duty and are designed to power more demanding devices. Note that ammonium chloride is a salt of weak alkali and strong acid, and therefore it hydrolyses and produces an acidic solution which fills the cell. In such an environment, zinc continuously dissolves, even when no electricity is drawn from the system. In order to counteract this phenomenon, various techniques are used to minimize the use of metal in the battery's idle state. One of them is amalgamation, i.e. covering the inner surface of a zinc cup with mercury. Mercury forms a solution with zinc, and the zinc amalgam virtually does not react with acids, but retains all the electrochemical properties of pure metal. Due to environmental protection, this way of increasing the durability of the cells is used less and less frequently (mercury-free cells are labelled as “0% mercury” or “mercury free”). Modern zinc-carbon batteries have a theoretical energy density of 40 to 70 Wh/kg. The operating temperature range is -10...+50°C. The lifetime of zinc-carbon batteries is about 2 years.
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When using zinc-carbon cells, remember not to leave them in the device after the battery runs out because of the possibility of electrolyte leakage. It causes corrosion and may lead to damage to the equipment.
Alkaline Energizer batteries
A milestone in the field of disposable batteries was the year 1955 and the construction of the alkaline cell. This was accomplished by a Canadian engineer, Lewis Frederick Urry, an employee of a company that today is known as Energizer. His cell lacks a carbon cathode and a zinc cup. Both electrodes are moist, separated pastes. A mixture of manganese dioxide and carbon acts as the cathode, while the anode is made of zinc dust mixed with potassium hydroxide. Both mixtures are additionally supplemented with thickening agents. The metal is used only for the pole terminals.
Alkaline cells are characterized by much better performance and, most importantly, higher current carrying capacity and increased durability. They also have a higher energy density, which theoretically ranges from 80 to 100 Wh/kg and a wider operating temperature range of -30...+70°C. The lifetime of such batteries is 5 to 7 years. Alkaline cells are marked with the letter L, for example, a standard R6 cell (commonly known as a “penlite” battery) in the alkaline version is marked LR6.
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Lithium batteries, e.g. AA lithium batteries are, in fact, lithium-manganese batteries. Their rated voltage is 3 V. They are resistant to temperature fluctuations and have a high energy density – up to 270 Wh/kg. This means that AA lithium batteries store almost three times as much energy as equivalent AA alkaline batteries. They are used, for example, in household appliances – clocks, camcorders, cameras, as well as computers. They store energy even longer, up to 10 years.
The family of lithium batteries includes many subtypes whose common denominator is the use of lithium or its compounds as an anode. Compounds used as cathode material include manganese oxide, thionyl chloride, sulphur oxide, iodine, silver chromate and others. These types of batteries can produce voltages from 1.5 V to 3.7 V – depending on the chemicals used.
Lithium-manganese batteries have an extremely long operating time, so they are often used to power devices that require a long lifetime, such as pacemakers, hearing implants, watches, powering configuration memory in electronic equipment, etc. Their undoubted advantages include resistance to high current discharge and a wide range of operating temperatures (even from -40 to +65°C).
In the past, batteries of this type were very expensive and therefore rarely used. Today, in addition to equipment requiring a long lifetime, they are used even in some toys. One of the most popular types of lithium batteries are the so-called button cells, commonly known as “3 V flat batteries”. They owe their name to their button-like appearance and small dimensions. Other types of these batteries are also available on the market, but due to their relatively high price compared to alkaline ones, they are less frequently used.
Due to their high durability, batteries made on the basis of this type of cells often have welded terminals, which make it possible to solder a batter to a board. In practice, if we use such a battery to power a CMOS RAM static memory or an RTC clock system, we can enjoy a few years of service life without the need to replace the power source.
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The rated voltage of silver cells is 1.55 V. The cathode of this cell is made of silver oxide and the anode is made of zinc. The electrolyte is a solution of potassium hydroxide. Silver batteries were invented at the end of the 19th century, but their large-scale production did not start until the 1960s. They are often referred to as silver oxide or silver-zinc batteries.
Silver batteries are characterized by stable output voltage and flat discharge characteristics. The voltage at the terminals of the cell drops very quickly when it is discharged. The theoretical energy density is 130...150 Wh/kg. Silver batteries are designed for use in devices which are sensitive to voltage fluctuations and require a stable power supply, e.g. measuring instruments.
The lifetime of a silver battery is approximately 2 years. Its major disadvantages include the fact that zinc is subject to corrosion in the alkaline electrolyte, which causes degradation of the battery. Therefore, it should be borne in mind that most often after about 5 years they start leaking, and thus pose a threat to the natural environment.
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Designations and dimensions of popular batteries
Below you'll find the most popular battery designations and dimensions available on the market:
AA batteries (double-A, penlite batteries)
“AA” batteries, commonly referred to as “penlite batteries” are alternatively marked as R6 in the standard version and as LR6 in the alkaline version. An “AA” battery is 14 mm in diameter and 50 mm in height. Its rated voltage is 1.5 V. The currently offered “AA” batteries have a capacity from 1600 to about 2500 mAh.
AAA batteries (triple-A batteries)
“AAA” batteries, a smaller version of penlite batteries, are equally popular and bear the designation R03 in the regular version and LR03 in the alkaline version. They have the same voltage as “AA” batteries. An “AAA” battery has a diameter of 10 mm and a height of 44 mm. They also have a smaller capacity – from 800 mAh to about 1200 mAh.
LR61, R14, R20 and other batteries
Another variety of even smaller penlite batteries are LR61 alkaline batteries. Their dimensions are 8.3 mm in diameter and 42.5 mm in height. Their rated voltage is 1.5 V and their capacity reaches 650 mAh. If a larger capacity is needed, use cylindrical batteries marked R14 or larger - R20. The dimensions of R14 batteries are 23 mm in diameter and 50 mm in height. Their capacity can be up to 8000 mAh. The largest of the popular cylindrical batteries is R20. The dimensions of R20 batteries are 33 mm in diameter and 58 mm in height. Their capacity is up to 21000 mAh.
Batteries with a voltage other than 1.5 V are manufactured by connecting cells in series. For example, the so-called flat battery comprises of 3 R10 cells connected in series. Others, such as the popular 9 V 6F22 battery, comprises six F22 cells connected in series, measuring 25 mm×15 mm×8 mm, enclosed in a single cubic casing.
The above mentioned battery capacity should be treated as a guideline, because due to the constant technological progress and the huge demand for efficient energy sources, these products are continuously developed and their parameters change. The dimensions and type designations of popular zinc-carbon and alkaline batteries are shown in the table below.
|Battery designation||Battery dimensions||Battery rated voltage|
|N||R1||910A||-||L=30.2 mm; D=12 mm||1.5 V|
|AAAA||LR61||25A||MN2500||L=42 mm; D=8 mm||1.5 V|
|AAA||R03||24A||MN2400, AM4, UM4, HP16||L=44.5 mm; D=10.5 mm||1.5 V|
|AAAL||-||-||-||L=50 mm; D=10.5 mm||1.5 V|
|AA||R6||15A||MN1500, AM3, UM3, HP7||L=50 mm; D=14.2 mm||1.5 V|
|-||R10||-||-||L=34 mm; D=21 mm||1.5 V|
|-||2R10||-||-||L=68 mm; D=21 mm||3 V|
|C||R14||14A||UM2, MN1400, HP11||L=50 mm; D=23 mm||1.5 V|
|D||R20||13A||MN1300, UM1, HP2||L=58 mm; D=33 mm||1.5 V|
|F||-||-||-||L=87 mm; D=32 mm||1.5 V|
|J||-||-||-||L=150 mm; D=2 mm||1.5 V|
|-||3R12||-||GP312S, flat battery||Cuboid 67 mm × 22 mm × 67 mm||4.5 V|
|-||-||-||lantern, 996||Cuboid 68 mm×115 mm×68 mm||6 V|
|PP3||6LR61, 6F22, 6R61||1604A||MN1604, block||Cuboid 48 mm×25 mm×15 mm||9 V|
|-||6F25||-||-||Cuboid 48 mm×25 mm×25 mm||9 V|
|PP9||6F100||1603||-||Cuboid 51.6 mm×65.1 mm×80.2 mm||9 V|
|-||4R25X||908||MN908||Cuboid 110 mm×67.7 mm×67.7 mm||6 V|
|-||4R25||915A||-||Cuboid 110 mm ×67.7 mm×67.7 mm||6 V|
|-||4LR25-2||918A||MN918||Cuboid 127 mm×136.5 mm×73 mm||6 V|
|-||-||-||PC926||Cuboid 127 mm×136,5 mm×73 mm||12 V|
Designations of lithium button cells do not require learning their parameters by heart, as they all have a nominal voltage of 3 V, while the dimensions are coded in the battery designation as follows: CR<2 digits, diameter in mm><2 digits, thickness - value ×0.1 mm>. For example, the numbers contained in the symbol of the popular CR2032 battery mean 20mm diameter and 3.2mm thickness.
Unfortunately, the above statement applies only to common types of lithium-manganese batteries with a nominal voltage of 3 V. Among button cells there are also silver batteries, which are marked in a different way.
What is the difference between batteries and rechargeable batteries?
In short, a battery is a disposable cell that becomes useless when the electricity stored in it depletes, because it cannot be recharged (i.e. power cannot be accumulated again). Their opposite are rechargeable batteries, that is cells with the life span from several hundred to several thousand cycles of charging and discharging.
A brief summary of the most important information about batteries
This short article describes only the most popular types of zinc-carbon, alkaline and lithium-manganese batteries. It is impossible to summarize 150 years of technology development and experimentation with various substances. Therefore, it omits almost obsolete mercury batteries, which are being withdrawn from use due to the content of environmentally hazardous substances and other, less popular in everyday applications, such as zinc-air or silver batteries.
Finally, a note that applies to all types of disposable cells. Despite various attempts by many people, disposable cells are not suitable for regeneration and must not be charged! The chemical processes taking place in the electrolyte cannot be reversed by charging, while the gas emitted during current flow can cause the cell to burst and explode.