Batteries

A battery is a chemical device that stores electrical energy in the form of chemicals and uses an electrochemical reaction to convert stored chemical energy into direct current (DC) electrical energy. The 1st battery was invented by Italian physicist Alessandro Volta in 1800. The electrochemical reaction in a battery involves the transfer of electrons from one material to another (called electrodes) by electrical current.

Functions:

Even if the term battery is used frequently, the basic electrochemical unit that is responsible for storing energy is called a cell. A cell, as just mentioned, is the basic electrochemical unit that is the source of electrical energy produced by the conversion of chemical energy. In its basic form, a cell typically contains three main components: two electrodes and an electrolyte, and it also consists of connectors, a separator, and a container. Speaking of electrodes, there are two types of electrodes called anode and cathode. 

 

The anode is the negative electrode (also called the fuel electrode or reduction electrode). It loses electrons to the external circuit and is oxidized in the electrochemical reaction. The cathode, on the other hand, is the positive electrode (also called the oxidation electrode). It takes electrons from the eternal cycle and is reduced during the electrochemical reaction. Therefore, the conversion of energy in a battery is due to an electrochemical oxidation-reduction reaction.

The third component of a cell is the electrolyte. An electrolyte serves as the medium for the transfer of charge in the form of ions between the two electrodes. Therefore, the electrolyte is sometimes called an ion conductor. Here it is important that the electrolyte is not electrically conductive, but only ionically conductive. A battery often consists of one or more "cells" that are electrically connected in series or parallel to provide the necessary voltages and currents.

Main types:

Basically, all electrochemical cells and batteries are divided into two types: 

1) Primary (non-rechargeable) 

2) Secondary (rechargeable) 

Although there are several other classifications within these two types of batteries, these two are the basic types. Simply put, primary batteries are non-rechargeable batteries, that is, they cannot be charged electrically, while secondary batteries are rechargeable batteries, that is, they can be charged electrically.

Primary battery:

A primary battery is one of the simple and convenient power sources for various portable electronic and electrical devices such as lamps, cameras, watches, toys, radios, etc. Since they cannot be electrically charged, they are useful and when discharged they are discarded.

primary batteries are usually inexpensive, lightweight, small, and very convenient to use with relatively little or less maintenance. Most primary batteries used in Household applications are single-cell batteries and generally have a cylindrical configuration (although they are very easy to manufacture in various shapes and sizes).

Types:

Zinc anode batteries were the predominant primary battery types until the 1970s. In the 1940s, World War II, and after the war, zinc-carbon batteries have an average capacity of 50 Wh / kg. The most important development in battery technology took place between 1970 and 1990. 

During this time the famous zinc/alkaline manganese dioxide batteries were developed, which slowly replaced the older types of zinc-carbon as the main primary battery. Zinc-mercury oxide and cadmium-mercury oxide batteries were also used during this period, but due to environmental concerns related to the use of mercury, these types of batteries were gradually phased out.

 

During this time, the development of batteries with lithium as the active anode material began and is considered a great achievement due to the high specific energy and longer service life of lithium batteries compared to conventional zinc batteries. Lithium batteries are manufactured as button and button cell batteries for a specific application (such as watches, memory backup, etc.), while larger cylinder batteries are also available.

The following table shows different types of primary batteries with their properties and applications. 

 1) Zinc - carbon - Common, inexpensive, various sizes - Radios, toys, instruments 

 2) Magnesium (Mg / MnO2) - High capacity, long service life - Military, and aircraft radios 

 3) Mercury (Zn / HgO) - Very high capacity, long service life - Medicine (hearing aids, pacemakers) 

 4) Alkaline (Zn / Alkaline / MnO2) - Very popular, moderate costs, high performance - Most popular primary batteries 

 5) Silver/zinc (Zn / Ag2O) - Higher capacity, expensive, shallow discharge - Hearing aids, photography, Pager 

 6) Lithium / soluble cathode -  High energy density, good performance, wide temperature range - Wide range of applications with capacities between 1 - 10,000 Ah 

 7) Lithium / solid cathode - High density of energy, low-temperature performance, long service life -  Replacement for button and cylindrical batteries 

 8) Lithium / solid electrolyte - Low power consumption, extremely long life, -  memory circuits, medical electronics

Secondary battery:

A secondary battery is also called a rechargeable battery because it can be electrically charged after it has been discharged. The chemical state of electrochemical cells can be "charged" to its original state by passing a current through the cells against their discharge direction.

Types:

In principle, secondary batteries can be used in two ways, In the first category of application, secondary batteries are primarily used as energy storage devices, where they are electrically connected to and are also charged by the main power source and, if necessary, they also supply energy. Examples of such applications are Hybrid Electric Vehicles (HEV), Uninterruptible Power Supplies (UPS), etc. 

The second category of secondary battery applications is those where the battery is used as the primary battery and is discharged. If it is completely discharged (or almost completely discharged), the battery is not disposed of but is recharged using a suitable charging mechanism. Examples of such applications are all modern portable electronic devices like cell phones, laptops, electric vehicles, etc.

The energy density of secondary batteries is relatively lower than that of primary batteries, but it has other good properties such as high power density, flat discharge curves, high discharge rate, and low-temperature performance. There are several other types of secondary batteries, but the four main types are:

There are several other types of secondary batteries, but the four main types are: 

a) lead-acid batteries 

b) nickel-cadmium batteries 

c) nickel-metal hydride batteries 

d) lithium-ion batteries

Lead-acid batteries:

Lead-acid batteries are by far the most popular and widely used rechargeable batteries. lead-acid batteries that were developed in the late 1850s. They have been a successful product for more than a century. Lead-acid batteries are available in a variety of configurations, from small sealed cells with a capacity of 1 Ah to large cells with a capacity of 12,000 Ah. 

One of the main uses of lead-acid batteries is in the automotive industry since they are used mainly as SLI (Start, Lighting, and Ignition) batteries. The first and most widely used rechargeable batteries are called lead-acid batteries. They are based on the electrochemical pair lead-lead dioxide (Pb - PbO2). The electrolyte used in these types of batteries is very common sulfuric acid.

Other applications for lead-acid batteries are energy storage, emergency power, electric vehicles (including hybrid vehicles), communication systems, emergency lighting systems, etc. The wide range of applications for lead-acid batteries results from their wide voltage ranges, different shapes and sizes, low costs, and relatively easy maintenance. Compared to other secondary battery technologies, lead-acid batteries are the most cost-effective option for any application and offer very good performance. 

The electrical efficiency of lead batteries is between 75 and 80%. Due to this efficiency, they are suitable for energy storage (uninterruptible power supplies - UPS) and electric vehicles.

Nickel-cadmium batteries:

Nickel-cadmium batteries or simply NiCd batteries are one of the oldest types of batteries available today, along with lead-acid batteries. Which were developed at the beginning of the 20th century. Nickel-cadmium batteries. 

They have a very long service life and are very reliable and robust. The second type of battery is called nickel-cadmium battery. They are based on nickel oxide hydroxide (nickel oxide) as a positive electrode and a cadmium metal base as a negative electrode. An alkaline solution of potassium hydroxide is used as the electrolyte.

One of the main advantages of NiCd batteries is that they can be exposed to high discharge rates and operate in a wide range of temperatures. Also, the lifespan of NiCd batteries is very long. The basic cost per watt-hour of these batteries is higher than that of lead-acid batteries but lower than that of other types of alkaline batteries. 

 

As mentioned above, NiCd batteries use nickel oxyhydroxide (NiOOH) as the cathode and metallic cadmium (Cd) as the anode. Typical consumer batteries have a line voltage of 1.2 V. In industrial applications, NiCd is second only to lead-acid batteries due to its low-temperature properties, flat discharge voltage, long service life, low maintenance requirements, and excellent reliability.

Unfortunately, there is an important property of NiCd batteries, the "memory effect", which is their only drawback. When NiCd batteries are partially discharged and then recharged, they gradually lose, ie, H. Cycle by cycle, their capacity. "Conditioning" is the process by which the lost capacity of batteries can be restored. Cells are fully discharged to zero volts and then fully charged again.

Nickel-metal hydride batteries:

These are relatively new battery types, an expanded version of the nickel-hydrogen electrode batteries that were used exclusively in aerospace (satellite) applications. The positive electrode is nickel oxyhydroxide (NiOOH), while the negative electrode of the cell is a metal alloy in which hydrogen is reversibly stored. After the technology was invented in 1967, work on NiMH batteries began at the BattelleGeneva Research Center. In 1989, the first NiMH consumer cells were launched.

During charging, the metal alloy absorbs hydrogen to form a metal hydride, and during discharge, the metal hydride loses hydrogen. One of the main advantages of nickel-metal hydride batteries over NiCd batteries is their higher specific energy and energy density. Nickel metal hydride sealed batteries are commercially available as small cylindrical cells and are used in portable electronic devices.

Lithium-ion batteries:

The lithium-ion battery turned out to be innovative and with its high specific energy, it became commercially superior. The advent of lithium-ion batteries in recent decades has been phenomenal. More than 50% of the consumer market has adopted the use of lithium-ion batteries. In particular, laptops, cell phones, cameras, etc. are the most important uses for lithium-ion batteries.

 

 

Akira Yoshino developed a prototype Li-ion battery in 1985, based on previous research by John Goodenough, M. Stanley Whittingham, Rachid Yazami, and Koichi Mizushima in the 1970s to 1980s, and then a commercial Li-ion battery was manufactured by a company. the battery developed by Sony. and the Asahi Kasei team under the leadership of Yoshio Nishi in 1991.

 

lithium-ion batteries have a significantly high energy density, high specific energy, and longer service life. Other main advantages of lithium-ion batteries are their slow self-discharge and the wide operating temperature range.

Reference:

1) https://www.britannica.com/technology/battery-electronics

2) https://www.science.org.au/curious/technology-future/batteries

3) https://en.wikipedia.org/wiki/List_of_battery_types

4) https://depts.washington.edu/matseed/batteries/MSE/classification.html

5) https://en.wikipedia.org/wiki/Rechargeable_battery

6) https://byjus.com/physics/uses-of-battery/