What is a battery and how does it work?

The battery, battery or also known as an accumulator is a device capable of generating electrical energy that is used to operate electrical and / or electronic devices such as cell phones, tablets, toys, LEDs, direct current motors, etc.

One of the main characteristics of these electrical devices is that they are only capable of generating direct current.

What is the difference between battery and battery? 

These terms come from the invention of the device capable of generating electrical energy and were not as confusing as today since everything depended on the way the components were placed either in a battery one on top of another or in the form of a battery Next to each other. You could say that in the batteries the two poles are on the same face, while in the batteries we find them at different ends.

Many times these two terms are confused, thus calling batteries to devices that are not rechargeable and batteries to what they are, but in reality, this way of classifying it is given in primary cells and secondary cells.


Primary cells

They are those that can only produce electricity during a single cycle since the chemical reaction suffered by the poles cannot be regenerated and therefore once they end their cycle they become unusable, they cannot produce more electricity.

Primary cell

Secondary cells  

These cells are of a more modern generation and are characterized by having the ability to be recharged for many cycles to be used again. This is because the chemical process that the electrodes undergo can be reversed through an injection or recharge of electricity.

Secondary cell

Parts of a battery

Although the batteries may be composed of different materials depending on each type, the basic structure is the same. We can find elements that are common and each of these has a special function.

Within the construction we can find different cells, each one contains two poles (anode and cathode) of different materials, a conductive electrolyte, and a housing.


As for the poles there may be a little confusing and this is because in the batteries the poles are inverse of what is normally used, the anode is the negative pole and the cathode is the positive pole, this is because the anode is the one that generates the negative charges or electrons.


How does a battery work?

The operation of a battery is based on an electrochemical reaction called Redox (reduction-oxidation). This simple word reaction is about an exchange of electrons between two poles, causing a change in the oxidation states of the materials.

battery diagram

The two poles are submerged in an electrolytic solution and each one reacts in a different way:

    • While the anode or negative pole reacts in the form of oxidation (oxidizes) due to the release of electrons.
  • The cathode or positive pole undergoes a reduction in oxidation (it is reduced) due to the gain of electrons.


As we know, this release of electrons from the negative pole travels to the positive pole through the circuit or device that is connected.

When the poles reach their limit, the cathode is charged with electrons and reduced, while the anode loses them and becomes oxidized. This process can be reversed through an external energy source, since excess electrons travel to the positive side of the battery and the lack of these on the negative pole is covered by the battery.

The batteries have a specific charging time set by the manufacturers so that the materials do not exceed their natural state.


As for the primary cells or non-rechargeable batteries, other types of materials such as carbon and zinc are used that cannot reverse the chemical process they suffer.

Types of batteries

There are many ways to classify these devices either by their shape, if they are dry or wet, without being primary (disposable) or secondary (rechargeable) cells, etc. On this occasion we will classify them by their type of cells since the other forms are not so exact, for example:

    • Batteries or batteries  wet  are named for the electrolyte used is liquid and the two poles are immersed in this
  • The dry ones use an electrolyte in the form of paste moist enough to conduct electricity because in these batteries there is no possibility of a leak or spill of liquid they are the most used today.


Disposable batteries or batteries (primary cells)

These devices are characterized by having a longer duration than the others but as the main feature, they can only be used during a discharge cycle.


Zinc – Carbon

These are the oldest and cheapest, consequently they store a smaller amount of energy and as a result, they last less than alkaline ones, they can be used in virtually any electronic device such as toys, radios, controls, watches, etc.

carbon battery


These batteries are shielded to prevent spills, are long-lasting and their applications are given in electronic components such as toys, radios, flashlights, cameras, watches, etc. Within this type we can find a classification by its size: 
Alkaline batteries

Within this type of batteries, we can find different models that are classified by their size, we can find from the most common they are: AA, AAA, C, D, and 9v, although there are also batteries for special uses such as J, N, A23, 21-23, AAAA, etc.

battery types


Within these, we can find those of silver oxide and those of mercury oxide.

With respect to mercury oxide, they should be treated with great caution since they are the most toxic because of their 30% mercury content. Its applications are based on precision instruments, calculators, clocks, hearing aids, etc.

Silver oxide

Batteries or rechargeable batteries (secondary cells)

Lead – Acid 

We can find two different types:

  • The VLA where the electrodes are submerged in excess of liquid electrolyte
  • The VRLA  where the electrolyte is immobilized in an absorbent separator or in a gel

This type of battery is usually composed of six cells connected in series which is equivalent to an approximate 12v and is mainly used in the automotive as a starter battery of engines, whether in cars, windlasses, bow thrusters, etc.

acid lead


They were created mainly to replace lead and acid batteries, they are characterized by having half the weight with respect to those of lead, we can find some variations of materials each with different characteristics:

    • Nickel-Iron (Ni-Fe)  They are very common in everyday life since they are used in toys, radios, cameras, etc.
    • Nickel – Cadmium (Ni-Cd)  They are manufactured in different shapes and sizes, the practitioner is the most used since they can be used in cell phones, laptops, portable electronic equipment, toys, etc.
  • Nickel – Metallic hydride (Ni-MH) They are practically the new generation since they have the capacity to generate 50% more energy and their possible uses are given in electric propulsion vehicles, hybrids, and portable electronic devices.



These batteries are the highest performance, since being compared with those of lead they can generate 6 times more energy using the same battery size. These are used in electronic devices of constant use such as tablets, laptops, smartphones. Due to its performance, its dimensions and its weight.

Within this category we can find those of:

    • Lithium-ion (Li-ion) They have a high energy density, have a low memory effect and due to their high energy capacity and reduced weight are used in portable electronic devices.
  •  Lithium Polymer (Li-Po)  These are used in applications that require more than 1A, reduced weight and size



These types of batteries are the promise of the near future as they promise a longer life, be cheaper and have much greater durability. It is worth mentioning that this type of battery is still in development.