Just look up and observe our surroundings, and it is not difficult to find that batteries are everywhere. Their invention has had a profound impact on our lives. They apply in every aspect of life, from some of the most common electronics such as cell phones, computers, and headphones, to cars, golf carts, and electric wheelchairs. Some batteries seem so small and insignificant that we can easily overlook them. But if we dig a little deeper, we see that each battery is a chemical experiment tank in which a chemical reaction is quietly taking place inside. Different types of batteries have different chemical reactions. In this article, we chose the newest member of the lithium-ion battery - lithium iron phosphate battery to find out what chemical reactions are happening inside it. First, we will look at the components of the LFP battery, then how it works, and finally introduce its advantages and disadvantages to give you an overall understanding of it. If you are an RV owner, off-grid enthusiast, or want to learn about lithium iron phosphate batteries, this article may be helpful to you.

What Is a LiFepo4 Battery?

Let's start with some basic battery concepts. A battery is generally a battery pack consisting of one or more small cells. One battery has three main parts: the positive electrode, the negative electrode, and the electrolyte. Although the materials used for the electrodes and electrolytes are different, the general principle of how a battery works is pretty much the same. Batteries generally use distinct materials as electrodes. One electrode loses electrons, and another electrode receives electrons. The electrode that loses electrons is usually the negative electrode. It produces positive ions and electrons. Positive ions flow into the electrolyte and react (move in or out). At the same time, electrons flow from the negative electrode to the positive electrode through the external circuit, supplying power to the devices on the wires. The electrode that receives electrons is usually the positive electrode. At the positive electrode, the electrons flowing through the external circuit to the positive electrode recombine with the ions coming out of the electrolyte to complete the chemical reaction. In a nutshell, a battery breaks down chemicals and converts them into electricity for our use.

Batteries divide into primary batteries and rechargeable batteries. Primary batteries are non-rechargeable and can only have a unidirectional chemical reaction. Once the internal chemicals deplete, they can no longer produce positive ions and electrons, and the battery is dead. Rechargeable batteries are reusable because the chemical reactions happening inside are reversible. They can be both charged and discharged. In theory, rechargeable batteries can continuously charge and discharge. However, in practice, they also will degrade over time and eventually become unusable.

Lithium iron phosphate (LiFePO4) batteries are subject to lithium-ion (Li-Ion) rechargeable batteries. LFP batteries generally use lithium iron phosphate as the positive electrode material and graphite as the negative electrode material. Lithium ions move back and forth from the positive electrode to the negative electrode through the electrolyte, providing energy storage and release. The nominal voltage of LFP cells is 3.2 volts, and usually, four lithium iron phosphate cells are connected in series as LFP batteries, as ideal 12-volt batteries.

How Does a Lithium Iron Phosphate Battery Work?

Lithium iron phosphate (LiFePO4) battery works on the same general principle as the battery chemistry mentioned above, except for the additional charging process. When the LFP battery is charging, the positive electrode of the LFP battery releases lithium ions and electrons. The lithium ions move to the negative graphite electrode through the electrolyte and then stay there. Electrons move along an external circuit from the positive to the negative electrode. After arriving, they will combine with the lithium ions retained there, depositing lithium there. When the battery is fully charged, the electrons stop moving, and the ions no longer pass through the electrolyte. When the LFP battery discharges, lithium ions move from the negative to the positive electrode through the electrolyte. The electrons move along an external circuit from the negative to the positive terminal, powering an external device. The ions and electrons then recombine at the positive electrode, depositing lithium. When the LFP battery is fully discharging, the electrons stop moving, and so do the lithium ions.

Pros and Cons Of LFP Battery

Pros

Lithium iron phosphate batteries have a high energy density and store more energy per unit weight or space. It is very suitable for people who have a requirement to occupy space. In addition, it has a long lifetime and long cycle life, generally can be used for 5-10 years, do not need us to replace often. The charging and discharging requirements are not as much as other types of batteries. It can completely discharge without affecting its performance. Non-flammable and heat-resistant features significantly reduce the possibility of fire and explosion.

Cons

Lithium iron phosphate batteries have higher upfront costs. In addition, they need to charge according to the manufacturer's recommendations, so you will need to purchase a new unit to charge. If you use a conventional charging device (such as a car's alternator) to charge it, the charging device will be damaged.