How Does A LiFePO4 Battery Works?

There are several lithium-ion batteries families in the market. Most of the consumers only know lithium batteries constructed from cobalt oxide, manganese oxide and nickel oxide, whose rated voltage is 3.7V.

However, there is a family of lithium iron phosphate batteries on the market, with a nominal voltage of 3.2V. These batteries are commonly called LiFe (lithium iron) or lithium iron phosphate (LiFePO4).

This new Lithium battery type is non-combustible that gives lower energy density. The LiFePO4 battery is not only safer to use but it has many other benefits that are not available in various lithium batteries, especially this battery can work well with high power applications.

If compared with other lithium and lead acid batteries, lithium iron batteries from Battle Born Battery have many more advantages such as high charging efficiency, long life, higher discharging, deep cycle capability, and high performance with maintenance. LiFePO4 batteries in the market are often higher in price, but due to longer lifespan, less maintenance charges, infrequent replacement make it worthy in this price tag.

In contrast, its lower rated voltage of 3.2V/cell reduces the specific energy below that of cobalt-based Li-Ion. Lithium iron battery is often used to replace lead acid battery used in automobiles. Four cells in series produce 12.80V, a voltage similar to six lead-acid cells in series that produce 12V. Vehicles charge lead-acid batteries up to 14.40V (2.40V/cell).

With four lithium iron cells in series, each cell with a maximum charging voltage of 3.60V, you have the same maximum charging voltage of lead-acid batteries, which is 14.40V.

The lithium iron battery is tolerant to some overload. However, keeping the voltage at 14.40V for an extended time, as most vehicles do on a long drive, can strain the battery.

Lithium iron battery has excellent safety and long life, but moderate specific energy and high self-discharge.

While lithium iron (LiFePO4) batteries aren’t exactly new, they’re just starting to gain traction in global commercial markets.

Li-ion batteries are called a “rocking chair” type of battery: they move ions, in this case lithium ions, from negative to positive when discharging, and back again when charging.

The red dots in cell are lithium ions, which move back and forth between the negative and positive electrodes.

On the left side of cell is the positive electrode, constructed from lithium-iron phosphate (LiFePO4). This explains the name of this type of battery. The iron and phosphate ions form a grid that traps the lithium ions. When the cell is being charged, these lithium ions are pulled through the polymer membrane in the middle, to the negative electrode on the right. The membrane is made of a type of polymer (plastic) with many tiny pores, making it easy for lithium ions to pass through. On the negative side, we find a lattice made of carbon atoms, which can trap and hold the lithium ions that pass through.

Battery discharge does the same in reverse: as electrons flow through the negative electrode, lithium ions move back across the membrane back into the iron-phosphate network. They are again stored on the positive side until the battery is charged again.

A fully charged battery would have these lithium ions all stored inside the negative electrode carbon.

In the real world, lithium-ion cells are made up of very thin layers of alternating aluminum-polymer-copper sheets, with the chemicals glued to them.

They are often rolled up like a swiss roll and placed in a steel bowl. 12-volt lithium-ion batteries are made up of many of these cells, connected in series and in parallel to increase voltage and ampere-hour capacity. Each cell is around 3.2 volts, so 4 of them in series make 12.8 volts.