A question I get asked commonly is “What exactly is the difference between Li-po (Lithium Polymer) and Li-on (Lithium Ion) batteries?” and to that I generally say quite a bit really. However in an effort to make that information available to everyone I have decided to write this article.
Now when looking at the world of battery powered devices you will notice things like RC Vehicles and Mobile Phones use Li-Po Batteries where as devices like Flash Lights and Remote Controls use Li-On batteries. Why is this? Well it turns out the reasons are both for efficiency and economics.
Lithium Polymer Batteries
There are many pros to Li-Po batteries. They weight far less then their Li-On counter parts and are far more malleable. This means they can be squashed down into flatter shapes which allows the size of the devices that house them to be kept small.
They have less internal resistance. This allows for faster discharging and higher amperage. This means you can adjust the amount of power being taken from the battery with far more ease. This is fantastic for RC Devices and Mobile phones as it allows them to adjust how much power they need for any given action.
Finally Li-Po batteries has less self aging when not in use. This allows them to be used for a longer period of time before the battery has been exhausted. They are also less prone to exploding so a integrated circuit is not required.
There is however two large downsides to Lithium Polymer Batteries. Firstly they are much more expensive to manufacture. This in turn makes the price of them much higher. Secondly they have a less energy density. This means that they will hold less energy then a Li-On of the same size.
Lithium Ion Batteries
Lithium Ion Batteries are basically the opposite of Lithium Polymer batteries. They are much heavier then Li-po batteries and are forced in to much more rigid shapes. This is why there is a universal standard for many Li-On battery sizes.
They have more internal resistance. This means there is slower discharging times and lower amperage in Li-On batteries. This is good for devices that have the same amount of power being drawn out of the battery on a regular basis.
Lion batteries have greater aging even if they remain unused for over a year. This means they can be purchased in bulk however if they are not used for a long time they will often die before you can get through them all.
Li-On batteries are also more prone to explosions this is why they require an integrated circuit to keep them in check.
So we can conclude that Li-Po batteries are used in RC devices because of their lower weight and faster discharge rates. Also because they have more power and larger amperage. They are used in mobile phones because they are much flatter allowing the phone to be lighter weight.
Lions on the other hand are used in things like flashlights and remote controls for their greater energy density, longer run times and more economical pricing.