Things to Know Before Choosing a Lithium Ion Battery
Since lithium batteries were first rolled out onto the consumer market in the early 1990s, they have undergone a great deal of development. This is almost to a point where modern li-ion batteries bear little resemblance to the first ones which made everything from laptops to cell phones possible. This rapid development, however, has not been a simple successive list of improved li-ion batteries. Rather, the number of lithium-ion products has exploded in many different directions.
It is worth considering just how diverse these types of batteries are in order to get a sense of the options facing those trying to decide which li-ion battery to use with a particular device or energy system. Li-ion batteries are what you will find underneath the chassis of an electric vehicle; they can be large plane-like cells, or they can be tiny buttons inside a smart watch. There are countless kinds.
The Choice is Yours
Or is it? In fact, the majority of li-ion powered products will come with their own tailor-made batteries, which will be used by the vast majority of consumers. Some companies, like Apple, have made their iPhone batteries almost irreplaceable, at east canceling the warranty if you try to replace it. Other products, such as the USB rechargeable AA smart batteries produced by tech company Pale Blue Earth, are themselves the battery that is being purchased, so there is not really any choice here either.
Rather, the people looking to actually have to choose an li-ion battery are usually those looking to power some much larger installation, or who are looking for a means of storing energy which they themselves have generated. Accordingly, we are not really in the realm of consumer products.
Important Terms for Li-ion Batteries
There are some particularly important parameters for li-ion quality, each making use of standard industry terminology. This is important to know before purchase. These are:
This is the overall system voltage at which the battery is designed to operate. Inputs at higher voltages than the nominal voltage are dangerous. You should certainly consider what the power input for your battery is and ensure it is lower than this voltage (although the rated voltage is usually higher than the nominal voltage) just to give a margin of safety.
The cycle refers the complete charge and discharge time of the battery. Incorporated within this will be cycle time and the half-cycle time, all of which are important details you will need to know.
Closely related to the cycle time – or at least the parameter that should be considered alongside it – is the current rate. This will indicate whether the battery is fast charging or not.
This refers to how the battery will cope with temperature change. Thermal runaway refers to the phenomenon whereby an increase in temperature will change the chemistry of the battery, meaning it will heat up even further. The point at which thermal runaway will be reached is an important thing to know.
This does not refer to the capacity, but it is used to calculate it. It the amount of energy that can be stored per unit mass. It is measured in Wh/Kg, and so it is the size of the battery, in combination with the specific energy, which determines the capacity.
It would be impossible to give an exhaustive list of all the various kinds if li-ion batteries out there, but these are the main parameters that define their use and applicability. Therefore, these are the thigs every battery owner should know.