Battery is an electrical device which consists of two or more voltaic cells connected in series to provide constant DC voltage. Cells are made up of electrodes (Cathode and Anode) and electrolyte (Acid or Base).

Voltage  inside the battery is produced due to electrochemical reaction i.e. addition and removal of electrons from cathode or anode. Electrodes are immersed in an electrolyte, which forces an electric charge to separate in the form of ions and free electrons.

Rechargeable battery and Non-Rechargeable battery

Types of Battery

Primary Cell: A cell which is non- rechargeable. For example: A button cell.

Secondary Cell or Storage Cell: A cell which is rechargeable. For example: Mobile batteries.

Types of Primary cell

Carbon-zinc dry cell: It is one of widely use primary cells. AAA, AA, C and D are some example of carbon-zinc dry cell. Negative electrode of cell is made of zinc and positive electrode is made of carbon.

Alkaline cell: A primary cell has low internal resistance in which positive electrode is made of Zinc and Manganese Dioxide is a cathode. This is immersed in alkaline electrolyte. Efficiency of these cells is high.

Silver oxide cell: A primary cell which is a miniature button form consists of Zinc anode and silver oxide cathode. This is immersed in either Potassium or Sodium Hydroxide electrolyte. Use in cameras, watches, hearing aids and small devices.

Silver oxide batteries.jpg
By Lukas A, CZE - Own work, Public Domain, Link

Types of Secondary cell

Lead-Acid Wet Cell: A secondary cell which consist of positive electrode (Lead Peroxide) and negative electrode (spongy lead metal) immersed in Sulphuric Acid. This cell is mostly used in application where high values of load current are required like in vehicles.

Nickel Cadmium Cell (NiCd): A type of rechargeable battery has nickel oxide hydroxide and metallic cadmium as electrodes immersed in Potassium Hydroxide electrolyte. It can deliver high current and has capacity to store charge for long periods of time. Use in Portable power tools, Alarm systems, TV equipment, Trimmer and many more.

Nickel-Metal-Hydride cell: A type of secondary cell has positive electrode (Nickel Oxide Hydroxide) and negative electrode (Hydrogen absorbing alloy). Higher capacity than NiCd cell. Use many for high-end portable electrical or electronic products.

Nickel-Zinc cell or Edison Cell: A type of rechargeable cell has positive electrode (Nickel) and negative plates (Zinc). It have limited life cycles for charging. Use previously in some railway applications.

Fuel Cell: A fuel cell is an electrochemical device that converts chemical (Hydrogen and Oxygen) into water produces electricity in the process. It is used extensively in the space program as sources of DC power. It is very efficient and capable of providing hundreds of kilowatts or power.

Battery Connection

Series Connection: When batteries are connected in series than total voltage available across the battery of cells is equal to the sum of the individual values for each cell. So, Voltage capacity will increase by connection individual cell in series.

Note: Current Rating of each cell must be same.

Parallel Connection: When batteries are connected in parallel than total current capacity will increases.

Note: Voltage rating of each cell must be same.

Series-Parallel Combination: To provide a higher output voltage and more current capacity, cells are connected in series-parallel combination.

Series and Parallel connection of battery

Internal Resistance of battery

By using of voltage division rule we can easily calculate the internal resistance of the battery.

Ri =( Vnl – Vl)/Il, Where Ri = Internal resistance of battery, Vnl = Voltage of battery at No load, Vl = voltage of battery at load, Il = current at load.



Calculate the value of internal resistance

Calculate Amperes-Hours of Battery

Capacity = Time * Load Current

Suppose, I have 2500mAh battery and my device required i.e. load current is 2 Amperes. Time up to which my battery will supply is calculate by

2500mAh = Time * 2 A

Time = 1.25 h

So, my battery will run for 1.25 hours.


Ajay Kumar Bharti

Ajay is an electrical engineer and android developer which share knowledge on different concepts of electrical topics. He believe in Learning by Doing.