Invention: According to most texts the "voltic pile," or electric battery, was invented in 1800 by the Count Alassandro Volta. Volta had observed that when two dissimilar metal probes were placed against frog tissue, a weak electric current was generated. Volta discovered he could reproduce this current outside of living tissue by placing the metals in certain chemical solutions. For this, and his other work with electricity, we commemorate his name in the measurement of electric potential called the volt.

However, the little ancient Battery discovered in a place called Khujut Rabu, just outside Baghdad suggests that Volta perhaps didn't invent the battery, but reinvented it. The jar was first described by German archaeologist Wilhelm Konig in 1938. The jars are believed to be about 2,000 years old and consist of an earthenware shell, with a stopper composed of asphalt. Sticking through the top of the stopper is an iron rod. Inside the jar the rod is surrounded by a cylinder of copper. Wilhelm Konig thought these things looked like electric batteries and published a paper on the subject in 1940.

A sketch of Bagdad Battery.

Understanding an Electric Battery: Electric Cell and Electric Battery:

A single unit of electro-chemical generator is known as Electrical Cell and when combination of several such units or electric cells connected electrically is known as a Battery. Several cells are combined and connected electrically in series or parallel to form a battery which have two main terminal electrodes one Positive and one Negative. The electrical potential difference between the two main electrodes depends upon the numbers of cells, types of cells and the types of combination used to form the battery.

In electronic circuits and diagrams an electrical battery is denoted by the following symbol:


Series Vs Parallel Connection of cells.

Series connection


Parallel connection

Difference between series and parallel connection of Batteries:

Battery in Series Connection: Cells can achieve higher operating voltages by connecting the positive terminal of one cell to the negative terminal of the other .When connecting our batteries in Series we are doubling the voltage while maintaining the same capacity rating (amp hours). This might be used in a scooter, Power Wheels kids’ vehicle, or other applications. We may just use a jumper wire between the negative of the first battery and the positive of the second battery.

Battery  in parallel connection, the capacity will be doubled but the voltage supply will be that of one of the individual batteries. In other words when batteries are hooked up in parallel, the voltage remains the same, but the power (or available current) is increased. This means that the batteries would last longer. In other words the two batteries would be able to power a 6 Volt device twice as long as a single battery.

How to connect batteries in series and parallel at the same time.

To join batteries in parallel, we are to use a jumper wire to connect both the positive terminals, and another jumper wire to connect both the negative terminals of both batteries to each other. Negative to negative and positive to positive. CAN connect our load to ONE of the batteries, and it will drain both equally.

Types of Battery:

Based on the electric properties batteries can be classified into two main groups:

Primary Battery:

Primary battery is the type of battery which is made up of primary cells (In a primary cell chemical reaction is irreversible). The energy is inherently present in the cells of Primary Battery. These kind of batteries are non-rechargeable and are for single time use. Batteries , used in hearing aids (zinc air type) are primary. All AAA, AA, and A type in torches, remote etc are also primary batteries.Examples of primary battery are: Leclanche  battery, zinc-chlorine battery, alkaline-maganese battery, metal air battery etc.

Secondary Battery:

Secondary Batteries or popularly known as ‘Rechargeable batteries’ find wide use everywhere. In our home inverter , mobiles , cars and trucks, in rechargeable torches also we use them.( Rechargeable batteries include lead-acid, nickel-cadmium, and lithium-ion batteries )

Secondary battery is the type of battery which is made up of secondary(  In a secondary cell chemical reaction is reversible.) cells. The energy is induced in the chemicals of the cells of the secondary battery by applying external energy or sources prior to using it. Examples of secondary battery are: lead-acid battery , nickel cadmium battery, nickle-iron battery etc.

Secondary cells are used in a variety of places due to it’s chemical and physical properties. The secondary batteries can also be classified into following types based on their use:

  1. Automotive / SLI / Portable Batteries.

These kind of batteries are used in automobiles and portable systems. The battery is used for Starting , Lighting & Ignition ( SLI ) in automobiles. Examples of Automotive or SLI or Portable batteries are: lead-acid batteries, nickel-cadmium batteries etc.

  1. Vehicle Traction / Motive Power / Industries Batteries.

These kind of batteries are used to power battery powered vehicles or to power various high power devices in industries. These kinds of batteries have high energy density in the range of 100-120 WattHour / Kilo Gram. Batteries like Lead-acid batteries, nickle-iron batteries silver-zinc batteries etc falls in this kind and also various high-temperature batteries are under development which also falls under this kind of batteries.

  1. Stationary Batteries.

These kinds of batteries are used in stationary systems, Such as standby power systems and load-leveling systems. These kind of batteries are used to store power when load is low or extra power is available and provide extra power to the system when load is very high or no power is available.

Cost Factor:

The price of rechargeable batteries is higher compared to that of non rechargeable ones. However, over the long term, using rechargeable batteries is more cost effective.

Non rechargeable batteries are cheaper compared to rechargeable ones.