Electric Car Batteries

Harrison Enright
November 30, 2016

Submitted as coursework for PH240, Stanford University, Fall 2016


Fig. 1: This is an example of what an electric car battery looks like, and where it could be stored in a car. (Source: Wikimedia Commons)

Electric car batteries are an alternative source of power for a car as compared to the traditional car battery. Battery Electric Vehicles, or BEVs, can make use of their battery to store electricity that can then be used to power the motor, which then turns the wheels, which then moves the car. This method is seen to be an effective alternative to using gas or diesel to power a car, since an electric car battery does the same job without producing any environmental tailpipe exhaust when the car is in use. These batteries are traditionally bigger than normal car batteries which is how they are able to store more energy, as can be seen in Fig. 1.

The Battery

There are many different types of batteries and vehicles, but the main one, the most efficient one, is lithium-ion. These batteries have 4 main components: a positive electrode, a negative electrode, a separator, and an electrolyte. [1] All batteries are generally similar in the way they work. When charging, the lithium ions from the positive electrode move through the electrolyte over to the negative electrode. It is here that the lithium ions stay until the battery is turned on and power is needed to power the car. Once the car is turned on, the lithium ions start moving back through the electrolyte from the negative electrode to the positive electrode. It is this process that creates energy which powers the battery for the car, thus powering the engine, which then in turn makes the car move. If the car is turned off, then the ions will cease to flow through the electrolyte at such a high rate that is necessary to power the car (some discharging will still occur, just at a much slower rate). Similarly, if the lithium ions all move over to the positive electrode side of the cell, and there are no more ions moving through the electrolyte, the battery will have no power and the car will shut off.


Electric car batteries have many clear advantages over normal car batteries. First of all, they don't use gas. It is estimated that electric car owners can save more than $1,500 annually of gas money. Additionally, electric cars have a very efficient way of storing and retaining their energy whilst driving. The battery will shut off when the car is stopped in order to save power, and while braking, the battery will actually recharge itself. This is called regenerative braking. Finally, the average driving range of BEVs on a single charge in this day and age is somewhere around 80-100 miles, which is more than enough for the majority of driver's daily use. [2] However, car manufacturers are attempting to develop batteries that can power cars for around 200 miles on a single charge, or even all the way up to 265 miles without dying. [2]


However many advantages there are for electric batteries, there are also disadvantages that have not been solved quite yet. First of all, the batteries potentially do not create zero emissions. They create zero exhaust emissions, and this is what most of the population believes to be the only emissions that matter, but the batteries also could produce heat-trapping gases in its manufacturing. And there is also the amount of pollution created during the extraction of fossil fuels in order to create the battery in the first place. So maybe these batteries aren't as clean as we may think. Additionally, these batteries are decently expensive to make. The Chevy Volt had a 16 kWh pack, and the battery pack cost about $500-$600 per kWh, so that would be around a minimum of $8,000 to manufacture. So it is not the cheapest way to make a car battery, but the goal is to have the number down to around $250 per kWh by 2020. [3] And finally, we have the disposal of the batteries when they finally die, which is an issue in its own that we are still trying to figure out a safe way to do so.


Currently, electric batteries are not the most popular choice for a battery nor are they anywhere near being the most common used in cars on the road. However, as they continue to get more efficient, cheaper, and easier to dispose of, they can become the most common car battery in our world. It is just a matter of time before it happens, as being environmentally friendly becomes more popular and necessary.

© Harrison Enright. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] E. Dyer, "5 Things To Know About Making Electric Car Batteries Better," Popular Mechanics, 30 May 16.

[2] B. Berman, "How Far (Literally) Can the Electric Car Go?," Popular Mechanics, 8 Feb 16.

[3] A. Dinger et al., "Batteries for Electric Cars: Challenges, Opportunities, and the Outlook to 2020," Boston Consulting Group, January 2010.