Depending on the way of generating electricity, batteries can be categorized into chemical battery, physical battery and biological battery, which has been a favorable research topic in recent years. Following is an introduction of these three kinds of batteries:

1. Chemical Battery

In the world of electrochemistry, chemical battery is also known as electrochemistry battery. Chemical battery is a device that transforms positive and negative electrode active materials into electricity through oxidation and reduction reaction. Depending on whether it’s rechargeable, it can be classified into two types: primary battery and secondary battery.

A) Primary Battery 

Including mercury battery, dry battery (zinc-carbon battery), alkaline battery (zinc-manganese battery)…etc.. They are a threat to the environment due to the fact they are not rechargeable.

B) Secondary Battery 

Including small batteries such as NiMH battery usually for the use of electric manual tools and li battery for 3C products; big batteries such as lead-acid battery for cars and motorcycles, NiMH battery for hybrid cars and li battery for electric cars. They are much more eco-friendly to the environment than primary batteries because they are rechargeable. 

Another kind of secondary battery is fuel battery. As the name suggests, it provides electricity for the device to use through adding fuel. Based on the current development of fuel battery, there are different kinds of fuel batteries including hydrogen-oxygen fuel battery, methanol fuel battery and zn-air fuel battery. 

2. Physical Battery 

Physical battery is a device that transforms thermal energy and light into electricity, including solar battery, heat battery and atomic battery. 

3. Biological Battery 

Biologists transform electricity produced in the bodies of animals into daily usage. For example, they generate electricity by incorporating oxygen with hydrogen produced by the reaction between carbohydrate and certain enzymes inside micro organisms. Due to the fact that hydrogen plays an important role in generating electricity, electricity can be successfully generated by using hydrogen which is produced by enzymes.