What is a Lithium Battery?

Compared to a lead acid battery, which true to its name contains heavy lead plates or glass matt barriers and liquid or gel acid, a lithium battery is in effect a box of electronics.

It comprises multiple lithium cells or cell packs, a battery management system (BMS) and some include a Bluetooth communications circuit board, all housed in various outer casings to ensure the internal components are protected at all times.

The job of the BMS is to protect the battery cells, manage the charge and discharge process in line with the manufactures specification and to prevent thermal runaway and other events that could damage the battery.

In all other respects a lithium battery looks and behaves very much like its lead acid cousin but with some crucial differences, which are noted below.

Different Lithium Chemistries

There are over 25 known types of lithium chemistry, but they share the common feature that they all contain an anode in the cell made from metallic lithium. All chemistry types have commercial usages for but the two most popular are Li-Mn – Lithium Manganese Dioxide and Li-FePO4 (most often referred to as LFP) – Lithium Iron Phosphate – this is where the Lifos company derived its name!!

Whilst each chemistry has its pros and cons, at Lifos we only work with LFP, which whilst being more expensive than others and being slightly larger in dimension, provides better long-term performance, is more stable and does not use Cobalt, which is mostly sourced from the Democratic Republic of Congo using unregulated labour.

LFP is becoming more widely used from utility scale storage right down to small personal charging equipment. Even Tesla has started to switch to LFP and many more in the EV world are following suit.

Packaging LFP Batteries

LFP batteries can be supplied in three main formats:

Tubular or cylindrical cells

These are similar to the AA type batteries we are all familiar with but are typically larger in dimension. The advantage of a tubular cell is that an entire battery pack can be created in any shape. The downside is that each battery must be connected to its neighbour by a metal tag and these connections can fail because of a dry joint or poor connection technique. A popular tubular cell specification is 18650 and typically 264 cells are needed to create a 12v/100A battery.

Pouch Cells

As the name suggests everything is housed in a pouch and this makes for a very slim line battery. Most commonly used in portable devices (phones and laptops) but the use is limited beyond these applications.

Cells Packs

These are individually a lot more powerful than a single tubular or pouch cell so significantly less of them are needed (typically 4 to create a 12v battery, 8 for 24v and 16 for 48v), thus the number of connections reduces massively – compare connecting 4 cells (for Cell Packs) to 264 (for Cylindrical Cells).

The Make Up of an LFP Cell Pack

Comprising of four components – a cathode, anode, electrolyte, and the separator:

Cathode - this determines the capacity and voltage of the battery and is where the lithium ions are generated.

Anode – allows electric current the flow through an external circuit – the lithium ions are stored in the anode

Electrolyte – salts, solvents and additives are the basis of the electrolyte and act as the channel for the lithium ions to flow between the cathode and anode

Separator – this is a physical barrier between the cathode and anode

Advantages of LFP

Longer service life. Typically, a lead acid battery will cycle 300 to 400 times before it needs replacing. Compare this to a Lifos battery that guarantees up to 2750 cycles (but many more can be expected), thus more than 6 times longer life than a lead acid battery.
Significantly smaller in dimension. Compare a lead acid battery at 100AH that has a useable capacity of 50% (50Ah) with a Lifos 105Ah battery that has a useable capacity of 90% (95Ah). In other words, almost 2 x 100Ah lead acid batteries would be needed to deliver the same useable power as 1 x Lifos 105 – in this case using Lifos virtually halves the space needed to store the battery
Low weight. LFP’s most famous advantage and what an advantage!! Take the example above – 2 x 100Ah lead acid batteries will weigh about 70kgs, compared to 1 x Lifos 105Ah at 11.9kgs – A whopping 58kgs weight saving!!
Safety. Unlike a lead acid battery, an LFP does not emit noxious gases so it can be used inside a living compartment, in a boat for example, without the fear of poisoning the occupants. In addition, LFP has a flash point of 2500 degrees C, can be used on its side and has no raw chemicals that could spill in the event on an accident.
Performance. Whilst a lead acid battery discharges on a steady downward curve signifying a reduction in battery voltage and current (appliances like lights get dimmer and radios get quieter), LFP batteries discharge without significant loss of voltage or current ensuring all appliances maintain optimum performance right up to the point where the LFP battery is fully discharged. The downside is that a conventional battery monitor will not give a truly accurate indication of the LFP battery’s state of charger. Therefore, most Lifos batteries have a built-in Bluetooth app that allows users to access important information about their battery on their smart device.
Cost. This could be described as a disadvantage because LFP batteries are significantly more expensive than lead acid and other lithium chemistries. However, when you calculate that your LFP will last 6+ times longer than a lead acid battery, it becomes clear why Lifos batteries are quickly becoming recognised as the new battery standard.

Disposal of Lithium

The world is waking up to the fact that by using more and more lithium powered products it is creating a problem of where will all these dead batteries eventually go. Landfill is not an option if we want to remove any possibility of soil contamination and water course pollution. At Lifos we are developing a second life program that encourages customers to return batteries to us at the end of their life where it will be stripped down, tested and repurposed to supply to low-income communities around the world with power, albeit sub optimal, for many more years.
Ultimately, once the cell pack is completely dead it needs to be stripped down to its granular level and each element either recycled or disposed of in a responsible and environmental way. At this time, there are several start-up companies who are focusing on this process and as soon as this service is commercially available, Lifos is committed to partnering with one or more organisations.