| Externally, modern autonomous power supply sources have little in common with the first battery device created by Alessandro Volta, but the basic principle remains unchanged. Each battery consists of three main elements - two electrodes, called anode and cathode and an electrolyte, located between the anode and cathode. The occurrence of an electric current is a by-product of the oxidation-reduction (redox) reaction, taking place between the electrodes. The output current, voltage and other parameters of the battery depend on the materials of the anode, cathode and electrolyte as well as on the design of the battery. All batteries can be divided into two classes - primary and secondary. In primary batteries, the chemical reactions are irreversible and in the secondary batteries, chemical reactions are reversible. Accordingly - secondary elements, which are known to us as storage batteries, can be restored (charged) and re-used.
One of the most important factors in the development of batteries (as well as any device using them) is to achieve a maximum specific capacitance for the given (minimum) size and weight of the element. Chemical reactions, taking place inside the element determine its capacity and physical size. In principle, the entire development history of batteries leads to the invention of new chemical systems and packing them in enclosure as small as possible.
Presently, different types of batteries are manufactured, some of which were developed in the 19th century and while others are barely decade old. Such diversity is explained by the fact that, each technology has its strengths.
Dry batteries:
The first commercially manufactured elements of power supply were dry. Heirs of the Leclanche invention, they are most prevalent in the world. Only one company Energizer sells more than 6 billion of such batteries annually. And this is despite the fact that they have the lowest specific capacity of all the many types. Such popularity is explained, firstly, because of them being inexpensive and secondly, that three different chemical systems are being called by this name: chlorine-zinc, alkaline zinc-manganese batteries (Leclanche elements). Their names give an indication of the chemical systems, based on which they were developed.
In dry elements, the carbon rod of a cathode current collector is located along the axis of the battery. The cathode itself is a system that includes manganese dioxide, carbon electrode and electrolyte. The zinc "cup" serves as an anode and forms the metal housing of the element. The electrolyte, in turn, is a mixture, which consists of ammonium chloride, manganese dioxide and zinc chloride.
Manganese - zinc and chlorine - the zinc elements differ by electrolyte. Manganese-zinc elements contain a mixture of ammonium chloride and zinc chloride, diluted with water. In chlorine – the zinc element, the electrolyte is zinc chloride by nearly 100%. The difference in the nominal voltage in them is minimal: 1.55 V and 1.6 V respectively.
Despite the fact that the chlorine-zinc elements have greater capacity as compared with the Leclanche elements, this advantage disappears at a low load. Therefore, "heavy-duty" is often written on the elements, i.e. high power elements. Whatever is the case, the effectiveness of all dry cells decreases considerably with the increase in load. That is why, it not worth using them in modern cameras since they are not intended for use in cameras.
No matter how much running around the pink bunnies do in advertising, alkaline batteries are the same carbon-zinc minerals of the 19th century. The only difference lies in a specially selected mixture of electrolyte, which allows increasing the capacity and shelf life of such batteries. What's the secret? This mixture is slightly more alkaline than the other two types.
If the chemical composition of alkaline batteries is a little different from the Leclanche element, then the design differences are significant. We can say that the alkaline battery is a dry cell, turned inside out. The outer enclosure of them is not an anode but a protective shell. Here, the anode is a jelly-like mixture of zinc powder mixed with an electrolyte (which, in turn, is an aqueous solution of potassium hydroxide). The cathode is a mixture of carbon and manganese dioxide, and envelops the anode and electrolyte. It is separated by a layer of non-woven fabric, such as polyester.
Depending on the area of use, alkaline batteries can last 4-5 times longer than conventional carbon-zinc batteries. This difference is especially noticeable in modes when short periods of high load are alternated with long inactive periods.
It is important to remember that alkaline batteries are not rechargeable, because the chemical processes, on which the batteries are based, are not reversible. If an attempt is made to charge the alkaline battery by fixing it in a charging device, then it will not behave like a rechargeable battery but more like a resistor. The alkaline battery will start heating up. If it is not removed from charging device, it may heat up enough to explode. |
Allesandro Volta, inventor of the first battery, was born on February 18, 1745. That's why February 18th is National Battery Day.
If you have a car, cell phone, computer, flashlight, or a wireless mouse, then you have batteries, and you may not realize how much they've improved in the past few centuries.
The next time you need batteries, choose rechargeables to help reduce the number of batteries that end up in our landfills.
