Types of Batteries: The Family Tree
Our body is a very sophisticated machine that elegantly breaks down the food we eat with the help of oxygen to release energy and gaseous carbon dioxide for our survival, and the process is called respiration. As to how respiration is related to batteries, the answer is simple — both are chemical reactions.
In other words, a battery does not magically produce energy to run the devices and hence, the technical definition of a battery is that it is a group of electrochemical cells used to supply DC power to various electrical devices. Read my post on Introduction to Batteries to better understand the technical definition and the parts of the battery.
Now that we are slightly more informed about batteries in general, it makes sense to ask — “What are the types of batteries?”, “How are they produced?”, “How did they become so popular?” and finally “What can we expect from them in future?”
The answers to all the above questions are directly (or indirectly) related to the answer of — what are the types of batteries? So, let’s find out…
Batteries are broadly classified into the following two categories:
Categories of Batteries
- Primary Batteries — Amongst all the types of batteries, it is probably the most popular one. These batteries are the “use and throw” type. Once completely exhausted, these batteries cannot produce any current for practical use and are discarded. Hence, they cannot be recharged. Zinc-carbon battery shown in Fig 1 is a popular example.
Another great example is this Wikipedia image, which shows a variety of commonly used primary batteries. - Secondary Batteries — These are rechargeable and are disposed of when they cannot provide current for practical use. The batteries are recharged when an external electric current is applied which reverses the chemical reaction.
To understand the chemistry in a simpler way, imagine yourself skiing from a 50 m high slope. When you ski down the slope you enjoy the easy ride downwards. To relive the thrilling experience, you walk up the entire 50 m slope against the gravity.
Like skiing downwards, the chemical reaction within the battery proceeds in (say) forward direction resulting in a discharging action (you expend the accumulated gravitational potential energy).
As you may have already guessed, the external electric current from the charger reverses the chemical reaction i.e. proceeds in the backward direction (thereby reversing the flow of electrons) to charge the battery which is analogous to walking up the slope against gravity (and accumulating gravitational potential energy).
Fig 2 shows a pack of nickel-cadmium rechargeable batteries along with a charger that charges (or applies external current to) the battery. To know more about the chemistry of rechargeable Ni-Cd batteries, visit here.
In the same skiing scenario, (say) after walking up the 50 m slope for over 10 times, you are exhausted and choose to walk only 20 m of the entire 50 m for the next round and eventually stop skiing. Similarly, after discharging and recharging multiple times, the chemical reaction does not proceed in either direction and the battery eventually dies.
Another very interesting similarity between the skiing analogy and the chemistry of secondary batteries is that just like how different people walk up and ski down at different rates, depending on the type of chemicals used, different secondary batteries charge and discharge at different rates. - Dry Cell — The only reason it is called “dry” because the electrolyte is not liquid wet, i.e. uses a dry paste (manganese dioxide, carbon powder and ammonium chloride in Fig 3) instead of a liquid electrolyte. The moisture content in the paste is just enough for conduction thereby negating the risk of direct contact with electrolyte due to spillage. Both zinc-carbon and nickel-cadmium batteries shown in Fig 1 and Fig 2 respectively are examples of primary dry cells.
On the other hand, their famous contemporaries — lithium ion and lithium polymer batteries are secondary (i.e. rechargeable) dry cells used in most of the modern day electronics. Carl Gassner was credited for this wonderful invention — truly, a unique variant of Leclanche Cell. - Wet Cell — As the name suggests, these types of batteries consist of a liquid electrolyte within the cell. Leclanche Cell is the one of the first wet cells ever developed. Like dry cells, they may be primary and secondary.
Most primitive cells like Daniell Cell, and Leclanche Cell were primary in nature and were used for lab experiments. Lead acid battery (shown in Fig 4) is one of the oldest examples of rechargeable batteries and is the most commonly used secondary wet cell as it lasts long and can be recharged multiple times. Thus, it is a customary power supply in automobiles.
In Fig 4, the liquid electrolyte is located within the protective physical container and can be accessed by opening the yellow coloured caps.
Fabrication
The next question that immediately follows is — “How are these batteries produced?”
Although, outlining the entire industrial production is beyond the scope of this article, the first principles can be illustrated by understanding the construction procedure of a dry cell in the patent — “ Method of manufacturing nickel zinc batteries “ by J. Philips and J. Zhao.
The patent describes methods of manufacturing a rechargeable battery. Refer to the “Claims” section in link to better understand the following explanation on identification battery components.
Remember, the first principles do not concern technicalities like chemicals involved, apparatus and the chemistry. Instead, it is focuses on identifying simple constituents involved in and affecting the working of a battery like :
- Positive and negative electrodes and materials used to fabricate them.
- Usage of particular chemicals (like dispersant in this case) to prevent or catalyze (here preventing the formation of zinc oxide) the formation of other unwanted or desired chemical substances respectively.
- Structure of the cell describing.winding and connection of electrodes.
- The separator sheet mentioned above is unique to this invention. Such accessories may or may not be used in other types depending on the application.
- The liquid or dry paste called the electrolyte to facilitate charge transfer for current generation.
For the curious bird — Try identifying the basic components in “Dry Battery” by M. Frank as an exercise.
Every battery has a few basic components without which it cannot be developed. The variants are built by playing with and tweaking them suitably depending on the applications, economics and principles of physics and chemistry.
Battery Buzz : Popularizing Types of Batteries
The story began in 1836, when J. F. Daniell invented the Daniell Cell followed by the invention of the dry cell in 1886 by Carl Gasner.
However, it was not until the invention of Columbia Dry Cell Battery, the first cylindrical dry cell in the last decade of the 19 thcentury by National Carbon Company (NCC) that commercial batteries really took off [6].
In simple words, it transformed the use of batteries from industrial power supplies to portable energy storage devices for consumers. As the Columbia Dry Cell Battery was a “dry cell”, it countered most problems faced by the wet Leclanche Cell like spillage and maintenance. (Click here to read more about Columbia Dry Cell Batteries).
Approximately, 50 years later in 1957, The Hamilton Electric 500 was the first electric watch ever produced followed by a flurry of new inventions like cell phone (just to be cautious, the word “cell” indicates cellular towers used to transmit electromagnetic waves for communication and not the electrochemical cell powering the device), Sony Walkman, portable gaming consoles and finally the fashionable electric cars.
It is fair to say that the National Carbon Company (NCC) was instrumental in reducing the size of batteries and driving them into our lives via various electrical devices.
Looking Ahead for the Different Types of Batteries
Undeniably, lithium batteries will be embedded in most consumer electronics and back up power supplies. On the contrary, paste based dry cells and liquid electrolyte based wet cells will not be wiped off because they are extraordinarily inexpensive.
Just like selecting “the right person for the right job” is an optimal solution, using “the right battery type for the right application” makes way for every viable type. The pros of using a cheap yet lasting primary dry cell in an electric torch outweighs the financial cons of using an expensive and rechargeable lithium battery. However, it is not wise to use a primary battery in a smartphone as the recurring costs may very well put a dent in your wallet.
Thank you everyone for your time.
References
[1] KhwajaDarbar, “Eveready Czn Battery Gold AA 1005 20P”, Amazon.in
[2] Envie, “Pack of 4, AA Ni-Cd Rechargeable Battery”, Amazon.in
[3] moXcel Store, Universal Battery Charger, Amazon.in
