The Different Types of Lithium-Batteries and Their Limitations

 Batteries were once heavy, bulky, awkward things that could only deliver a small amount of current for their weight and size. But with the rapid improvements in battery technology, we now have high-power, capable lithium batteries that can provide all the power your appliances and devices need. The first commercial lithium-ion battery entered the marked almost 30 years ago, and has since seen a lot of development which has led to the proliferation of different types of battery and technologies depending on the materials and construction used. In order to get the most out of your lithium batteries, you need to know what type of battery you've got, what their limitations are and how to make sure they last for as long as possible.

Types of Lithium Batteries

Lithium-Ion (Li-Ion) Batteries

Lithium-ion batteries, also known as li-ion, refer to rechargeable lithium batteries, and to the traditional cells built in metal, cylindrical bodies, specifically. Such a cell is the venerable 18650, but when you're looking to buy lithium-ion batteries, you'll also find a range of sizes and types. The stout casings are what makes these cells popular for applications where toughness is needed.

Lithium-Polymer (Li-Po) Batteries

Lithium-polymer, also known as li-po batteries, are basically lithium-ion batteries that use a polymer electrolyte in place of a liquid electrolyte. This allows the construction of the pouch cells with different geometries, making them more flexible in terms of design. As a result, these batteries are useful for applications like tablets and smartphones, where you need a high-capacity battery with a flat form factor. These batteries are also popular in RC models due to their lightweight construction.

High Voltage Lithium (Lithium-HV) Batteries

These batteries are basically lithium polymer batteries, but instead, feature a special silicon-graphene additive on the positive terminal in order to resist damage at higher voltages. Most lithium batteries experience reduced lifespan and capacity loss when charged above 4.2V, but thanks to this additive, lithium-HV batteries can be charged to 4.35V without experiencing these negative effects. This provides about a 10% gain in energy density when compared to conventional li-po batteries.

Lithium-Iron-Phosphate (LiFePo4) Batteries

These batteries are an altered lithium-ion chemistry, and are capable of withstanding more charge cycles. However, they lose some of their energy density as a result. These batteries operate ideally in the 3V-3.65V range instead of the typical 3V-4.2V range of standard lithium-ion batteries. And the fact that they have a flat discharge voltage curve makes them a great replacement for 12V lead-acid batteries in a large range of applications where 4 cells are a suitable substitute for the original 6 cells. These batteries are more stable, and with lower rates of capacity loss and self-discharge over time.

Respecting the Battery's Limits

Unlike most other battery types, lithium cells aren't as tolerant of mistreatment. Discharging them below their voltage limits can lead to the formation of copper dendrites that can hinder their capacity or kill them completely. Overcharging them can lead to damaging the anode by lithium playing out of solution, resulting in lithium dendrites, leading to a full thermal runaway or short circuit of the battery. This can release smoke and potentially flames. 

Worth noting is that each cell in the battery pack must be kept at the same voltage as its surrounding cells to avoid premature damage. Lithium cells shouldn't be charged quickly, and ambient temperatures can also play a crucial role in their performance. These batteries don't like being in below-freezing temperatures, especially if they're fully charged. Charging them below 0 degrees Celsius is impractical, as metallic lithium can electroplate at the negative electrode, leading to significant damage or short-circuiting the cell. Damage will also occur if the batteries are charged at temperatures of over 45 degrees Celsius.

If you don't respect the battery's limits, you'll end up with a dead battery at best, or an explosion and fire at worst. These batteries also tend to outgas, swell up, or just become a hassle to deal with. While it may look difficult to maintain lithium batteries, it's actually quite easy if you're cautious and mindful.

Conclusion

Whether you decide to buy lithium-ion batteries, li-po batteries, lithium-HV or LiFePo4 batteries, you need to make sure you take proper care of them. The difference between the types is small in terms of cell chemistry, but even these small differences can play a huge role in the performance of your devices or equipment. That being said, before you decide on the best lithium battery for your application, make sure you understand the power requirements of your devices in order to ensure you make the right choice. Charging is a large part of the maintenance process, so make sure you get a suitable charger that's specifically meant for charging lithium batteries, otherwise, you risk overcharging them and shortening their lifespan significantly.